- The claimant,
Rohm & Haas Company, is the registered proprietor of European Patent EP
0 484 147 B1 ("the patent in suit") filed on 30th October 1991, granted on
26th August 1998. Its brief description is "propanil dispersible granule formulation".
It teaches a process for manufacturing water-dispersible granules containing
propanil, which is a herbicide used in agriculture. It claims a priority date
of 31st October 1990.
- The defendant,
Collag Ltd, has employed two different processes for manufacturing herbicide
granules. For convenience, these processes have been referred to as "Process
A" and "Process B". The present proceedings were initiated by the claimant,
whose claim alleges that Process A infringes the patent in suit. In its defence,
the defendant not only denies that Process A infringes, but it also counterclaims
for revocation of the patent in suit, and for a declaration that Process B
does not infringe. In relation to both Process A and Process B, the defendant
denies infringement on the grounds that neither process involves the formation
of a paste prior to extrusion. In relation to Process B only, the defendant
raises an additional ground for justifying non-infringement of the patent
in suit.
- With a view
to being able to manufacture propanil granules by Process B and to market
the resultant product, without having to wait for a determination as to the
validity of the patent in suit or as to whether the fact that both processes
involve the formation of a paste prior to extrusion renders them non-infringing,
the defendant applied for the determination of a preliminary point. That application
came before Laddie J on 24th February 2000, and, over the objection of the
claimant, he ordered the following issues to be tried:
Whether Process
B comprises the step of combining one or more surfactants with propanil and
milling to particle size of less than 20 microns to form a premix; and if
not
Whether by reason
of the absence of the said step, the use of Process B (and accordingly any
dispersible granules produced by such process) does not infringe any claim
of the patent in suit.
- These preliminary
issues now comes before me for determination.
TECHNICAL BACKGROUND
- Depending on
factors such as the physical and chemical properties of the active ingredient,
the method of application and the mode of action, agrochemicals are manufactured
in a number of different formulations. Thus, some are supplied in liquid form,
such as solutions, emulsions or suspensions, and others in solid form, such
as powders or granules.
- A problem in
the field of solid agrochemicals has been how to manufacture formulations
which are not only convenient and safe, but which also contain a high concentration
of active ingredient which will efficiently disperse in water before being
sprayed onto crops. Where that ingredient is milled into very fine particles,
normally in order to ensure efficient dispersion, this can create a number
of problems. In the case of powders, the product can be difficult to handle,
and can also be liable to "pack" during carriage, which can lead to inconsistent
dosing levels. In the case of granules, the product can often be difficult
to disperse in water.
- As at 31st October
1990, water dispersible granules containing agrochemicals were well known;
they were made by mixing the ingredients in powder form and then granulating.
Mixing could be effected by blending and/or milling, for instance, by an air
mill using jets of air to break up particles to a smaller size. Granulating
could also be effected by a number of techniques, one of which was extrusion
granulation, which involves making a wet paste from powdered ingredients and
forcing it through an extrusion machine, followed by drying.
- An essential
ingredient of such water-dispersible granules was a surfactant (a shortening
of the expression Surface Active Agent). Surfactants were known to act as
wetting agents and as dispersing agents. A wetting agent, when added to liquid,
increases the spreading or penetrating power of the liquid by reducing interfacial
tension between the liquid and the surface on which it spreads. A dispersing
agent adsorbs on to the surface of particles in a liquid medium, and helps
to prevent their reaggregation.
- To act as a
wetting agent, at least in water, a substance must be amphiphilic in nature.
A substance is amphiphilic if it consists of molecules having both hydrophilic
(water loving) and hydrophobic (water hating) ends. Such molecules orientate
themselves at a surface and effectively reduce surface tension.
- A number of
other ingredients were frequently included in water dispersible granules.
Anti-foaming agents were, as their name suggests, added to prevent excess
foaming. These were often themselves surfactants. Flow aids, milling aids,
fillers and carriers such as clays, silica particles or starch were often
included in the process to stop the particles sticking together, to soak up
the moisture, to assist the flow, and to adjust the composition. Disintegrants,
such as starch, sugar or inorganic salts were also used to break up the granules
on the addition of water.
- As mentioned
above, propanil is a herbicide, i.e. a weedkiller. Its chemical name is N-(3,
4-dichlorophenyl) propionamide. It is solid at room temperature, but melts
at around 92ºC. Accordingly, any processing of propanil involving heat or
pressure can run in to the risk of the particles becoming sticky; if that
happens, they tend to agglomerate.
THE PATENT IN SUIT
- Having explained
that the claimed invention "relates to a process for preparing dispersible
propanil granules", and having described two earlier patents, the specification
continues at page 2, lines 14-23:
"In attempts
at making pesticide granules, it has often been found that granules or agglomerates
prepared from the formulated wettable powders of the art using well-known
agglomerating techniques and using water as the agglomerating agent, are not
easily dispersible in water. On the other hand, agglomerates which are readily
water-dispersible are often not sufficiently resistant to attrition and form
a fine dust fraction upon handling and shipping. If conventional binders are
added to make the granules strong, then they are not dispersible in water.
[Certain techniques which have already been discovered] have also been used
to form granules containing up to 50% of active pesticide, but the resulting
granules are not rapidly or completely water dispersible and are not suitable
for use in preparing sprayable suspensions."
- After referring
to propanil, there is this at page 2, lines 27-30:
"A ... herbicide
composition designed for dispersion in a liquid carrier should ideally have
a high content of active material, should be readily dispersible in the carrier,
and should then form a dispersion which is as stable as possible, requiring
the minimum of subsequent agitation for homogeneity. The liquid carrier will,
of course, for convenience normally be water."
- Immediately
afterwards, at page 2 lines 31-35 the specification continues:
"Low-melting
solids such as propanil present an especially difficult problem in the preparation
of a dispersible granule formulation. The low-melting solid, herein defined
as melting below 100º C, tends to melt or become sticky during or subsequent
to the grinding process which is a necessary step in preparing dispersible
granules. [An earlier patent] requires micro-encapsulation [which] involved
additional pressing steps and adds to the cost of the overall formulation."
- At lines 36-41
of page 2, the specification continues:
"[An earlier
patent] discloses a process for the preparation of water dispersible granules
comprising admixing the desired ingredients of the granules into an extrudable
form, extruding the mix and then rolling the extrusions and optionally drying
the extrusions. The desired ingredients may comprise propanil.
In the case of
the herbicide propanil, it has not heretofore been possible to produce a dispersible
granular product which combines the features of a high active ingredient content
and good suspensibility and dispersant properties, as well as resistance to
attrition - thereby avoiding the formation of a dust."
- At page 2 lines
45-48 there is this:
"We have now
discovered a process for producing dispersible granule formulations of propanil
herbicide. The process can provide granules which contain more than 60% active
ingredient, which also have good suspensibility and dispersability characteristics,
and which resist attrition."
- The invention
is then summarised in precisely the same words as are to be found in Claim
1, which I will set out below.
- On page 3, the
specification contains a number a statements and definitions upon which either
or both of the parties rely. Thus, the expression "granular form" is described
as meaning "granules substantially or which have a mean particle size of at
least 1mm ...". At page 3 lines 10-11 one finds this:
"In addition
to the active ingredient, propanil, the mixture to be formed into dispersible
granules contains one or more surfactants and, optionally, flow enhancing
agents, dispersants, wetting agents and defoaming agents".
- At lines 18-20
of page 3, the specification explains how to measure dispersability, and at
lines 21-22 the term "attrition" is explained. At page 3, lines 25-28, there
is this:
"The term "surfactant"
is used in the broad sense, to include materials which may be referred to
as emulsifying agents, dispersing agents and wetting agents, and the surfactant
component may comprise one or more surfactants selected from the anionic,
cationic and non-ionic type".
- At page 3 lines
42-43, the specification continues:
"In the context
of this specification a dispersing agent is a surfactant which facilitates
the dispersion of the pesticide particles when the product is added to a liquid,
for example water."
Examples of surfactants
which are wetting agents are given at lines 47-49.
- At page 3, line
50, the specification contains this:
"All surfactants
act as dispersing agents to some degree, and also to some degree as wetting
agents ...".
- At page 3, lines
53-57 one finds the following:
"Small particles
of a low-melting solid such as propanil often stick together thereby causing
flow problems in processing the material. Flow aids such as clays or silica
particles may be used to minimize these problems. Flow aids preferred for
the propanil dispersible granule include [certain specified proprietary brands].
The flow aid content of the dispersible granule may vary from 0 to 10%...."
- On page 4 of
the specification, there is this at lines 3-8:
"Disintegrants,
which are water soluble, organic compounds such as starch or sugar or inorganic
salts such as sodium acetate or sodium bicarbonate, are sometimes used in
dispersible granule formations. ... We have found these disintegrants have
adverse effects on the propanil dispersible granules prepared according to
this invention. ... Consequently, granules prepared according to the present
invention are preferably substantially free of disintegrants."
- The final part
of the specification to which I should refer is at page 4, lines 12 and 13:
"Dust content
and resistance to attrition of the propanil dispersible granules prepared
according to this invention are minimised by forming the granules by the preferred
mode of extrusion".
- Page 5 of the
specification contains a table setting out certain proprietary dispersants,
wetting agents, flow aids and defoaming agents. There then follow a six pages
of "Examples" and experiments. On pages 12-13 of the patent in suit, there
are the Claims. Claim 1, which as I have mentioned, is effectively reproduced
in the specification, is in these terms:
"Process for
producing a dispersible propanil granule comprising:
a) combining
one ore more surfactants with propanil and milling to a particle size of less
than 20 microns to form a pre-mix;
b) adding less
than 25 per cent by weight water and optionally a wetting agent to the said
pre-mix and mixing until a paste is obtained;
c) granulating
said paste thereby producing granules; and
d) drying said
granules to a moisture content of less than 2 per cent by weight."
- It is necessary,
for the purpose of dealing with the arguments raised in these proceedings,
also to set out Claims 4, 5 and 10:
"4. Process
according to any preceding claim wherein one or more of a dispersant, a flow
aid and a defoaming agent are added during step (b).
5. Process
according to any preceding claim comprising the steps of:
a) milling a
mixture of propanil dispersant and flow aid to a particle size between 3 and
15 microns;
b) adding a wetting
agent dissolved in 12-20 per cent by weight water to the milled mixture of
step (a) and mixing until a homogeneous, extrudable paste is obtained;
c) extruding
said paste to form granules; and
d) drying said
extruded granules ...
...
10. A dispersible
granule according to any one of claims 6 to 9 [which by virtue of claim 6
includes claims 1 to 5] which is substantially free of disintegrant."
THE
ISSUES BETWEEN THE PARTIES
- Arising out
of Laddie J's order, there are two substantive disputes between the parties.
The first dispute concerns the meaning "surfactant" as that expression is
used in the patent in suit, and in particular the meaning of the expression
"one or more surfactants" in claim 1(a). The defendant contends that the expression
is limited to amphiphiles, that it is limited to substances which perform
their function in relation to two media, at least one of which is liquid.
The claimant, on the other hand, argues that the expression "surfactant" can
and, in the context of the patent in suit, does include non-amphiphiles and
that it extends to any substance which is active at the interface of two phases
to modify the surface energy of the substrate.
- Whoever succeeds
on the first issue, it is still necessary to consider the second issue, namely
whether Process B infringes the patent in suit. It is true that if the defendant
succeeds on the first issue, Process B does not, at any rate at first sight,
infringe the patent in suit, because it does not involve the addition of a
surfactant (on the defendant's definition) at the stage identified in paragraph
(a) of Claim 1. However, the issue of infringement still nonetheless arises.
Equally, if the claimant succeeds on the first issue, the defendant still
contends that Process B does not infringe, and the second issue falls to be
resolved.
- There is another
issue between the parties, namely as to which of them has the burden of proof.
I shall deal with that issue first, and I will then turn to the substantive
issues which divide the parties.
THE BURDEN OF PROOF
- The claimant's
case is simple. The preliminary issues ordered by Laddie J, and which I am
determining, both arise out of the defendant's counterclaim which seeks a
declaration that, irrespective of the validity of the patent in suit and irrespective
of the question of whether Process A infringes or not, Process B does not
infringe. Accordingly, runs the claimant's argument, given that it is the
defendant who is seeking that relief, the burden of proof lies on the defendant.
- In the absence
of special circumstances, which, he contends, exist in the present case, Mr
Christopher Floyd QC (who appears with Mr James St Ville for the defendant)
accepts that the claimant's argument would be correct. In other words, where
a person (whether claimant or defendant) seeks a declaration that a particular
process or product does not infringe a patent, the onus lies on him to establish
that he is entitled to the relief he seeks, even though it is in effect a
negative declaration, rather than on the patentee. The correctness of this
concession seems to me to be supported by what was said by Scarman LJ in Mallory
Metallurgical Products Limited -v- Black Sivalls & Brison Incorporated
[1977] RPC 321. In that case, the plaintiff was seeking a declaration of non-infringement
under Section 66 of the Patents Act 1949, and, at 345 lines 28-30, one finds
this:
"The burden of
proving the absence of infringement rests, in my judgment, upon the plaintiff.
If there be a lack of clarity or precision, the court is not in a position
to grant the declaration sought."
- In the present
case, the claimant, in its original pleading, contended that the defendant's
product, which was in fact manufactured sometimes by Process A and sometimes
by Process B, infringed the patent in suit. However, at that time, Mr Henry
Carr QC (who appears with Mr Piers Acland for the claimant) says, and I accept,
that the claimant was unaware that the defendant employed two different processes
for manufacturing its product. It was only on 9th December 1999, that the
defendant alleged for the first time that it had been using two different
processes. Shortly thereafter, the defendant asked for acknowledgement from
the claimant that Process B did not infringe, and the claimant refused to
grant it. It was for this reason that the defendant counterclaimed for a declaration
of non-infringement in relation to Process B.
- It seems to
me that the thrust of the pleadings and correspondence is as follows. The
claimant did not distinguish between Process A and Process B in its allegation
of infringement against the defendant, because it was unaware that the defendant
employed more than one process to manufacture its product. Once the defendant
made it clear to the claimant that there were two separate processes, the
parties proceeded on the basis that the claimant would be contending that
Process A infringed, and was prepared to leave it to the defendant to decide
whether to seek a declaration that Process B did not infringe. The defendant
decided that it did wish to ask for such a declaration, and accordingly it
counterclaimed appropriately. It is pursuant to that counterclaim that the
preliminary issues ordered by Laddie J arose.
- From this, and
from the terms of the correspondence (which I do not propose to discuss in
any detail, not least because to do so would add unnecessarily to what is
to be an over-long judgment) I extract the following two conclusions. First,
it is solely the defendant's counterclaim for a declaration of non-infringement
from which the instant preliminary issues are derived. Secondly, the claimant
has been playing the system, in that, having first brought these proceedings,
in relation to the defendant's product and its Process A, it is now leaving
it to the defendant to decide whether to seek a declaration of non-infringement
as to Process B.
- In the absence
of the second conclusion, it seems to me that it would follow that the burden
of proof is on the defendant, in light of Mr Floyd's concession, which is
probably inevitable following Mallory (on the basis that the principle
is no different under the current Patents Act). Although the claimant's attitude
to Process B in these proceedings might be thought, according to taste, to
be unattractive, tactical, canny or commercial, it is certainly not an abuse
of the process of the court. Indeed, the very existence of the present preliminary
issue shows that it cannot even be said that Process A and Process B have
to be considered together. In those circumstances, if the worst that can be
said about the claimant is that it is playing the system, I do not see that
as a valid reason for a different result as to where the burden of proof lies
in the absence of the claimant being open to such a charge.
- It is true that
the claimant has not amended its original formal allegation of infringement
against the defendant, which can therefore be fairly said to extend to Process
B. However, it seems to me that, on a fair reading of the correspondence,
the claimant made it clear to the defendant that, as soon as the claimant
was told that the defendant had two processes, it was only Process A which
was said to infringe. That the defendant accepted this is supported by the
very existence and terms of its counterclaim, which only refers to Process
B.
- In these circumstances,
I am of the view that the burden of proof in relation to the preliminary issues,
which I have to consider, lies on the defendant.
PRINCIPLES
OF CONSTRUCTION AND THE EXPERT EVIDENCE
The
approach to construction
- The first issue
(and indeed, arguably, the second issue) between the parties is ultimately
one of pure construction for the court. In many, indeed most, cases of construction
of a patent, expert evidence is not admissible - see for instance Lubrizol
Corporation -v- Esso Petroleum Co. Ltd [1998] RPC 727 where the point
is summarised in the headnote at 730, paragraph (4). However, in the present
case, each party has called two expert witnesses. The reason is that the word
"surfactant" has a technical meaning, and therefore expert evidence is admissible.
The claimant called Michael Hounslow, Professor of Chemical Engineering, and
Head of the Particle Products Group at the Department of Chemical and Process
Engineering, at the University of Sheffield, and Anthony Ryan, Professor of
Physical Chemistry, and Head of the Department of Chemistry, at the University
of Sheffield. The defendant called Paul Luckham, Professor in the Department
of Chemical Engineering and Chemical Technology at the Imperial College of
Science, Technology and Medicine, London, and Mr Alan Knowles, who is, and
has been since 1992, principal of his own consultancy offering advice and
training in the area of environmentally friendly pesticide formulations, having
previously worked for 22 years in the agrochemical division of ICI.
- The correct
approach to construction of patents has been laid down in a number of cases,
including two recent decisions of the Court of Appeal, Hoechst Celanese
Corporation -v- BP Chemicals Ltd [1999] FSR 319 and Cartonneries de
Thulin SA -v- CTP White Knight Ltd (unreported, 25th May 2000). In the
former case, Hoechst [1999] FSR 319, the headnote, at holding (2) on
page 320, summarises the correct approach as being:
"Purposive construction,
namely the ascertainment of meaning having regard to the purpose of the words.
The close analysis of the words in the specification carried out by the parties
amounted to the literal analysis which had been rejected as wrong."
- In the latter
case, Cartonneries (unreported), the Court of Appeal, through Robert
Walker LJ, referred to "an inadmissible attempt to use other parts of the
specification to put a gloss on the clear language of the claim" (page 12)
and considered, at page 37, that the right approach was to consider "the ordinary
meaning of the words used in [a] claim" and then consider whether there was
anything to "indicate a narrower [or indeed a different] construction". As
was said by Mr. Carr, the cases show that the court must avoid the extremes
of the strict literal construction on the one hand, and, on the other hand,
an approach to the claims which treat them merely as a guideline. The court
must strive to adopt an approach which leads to fair protection for the patentee
and reasonable certainty for the public - see e.g. per Hoffmann J in Improver
Corporation -v- Remington Consumer Products Ltd [1990] FSR 181 at 189-190
referring to Article 69 of the European Patents Convention.
- If the defendant
wins on the first issue, the second issue will involve considering whether,
given that the defendant's Process B involves a literal departure from the
process claimed in the patent in suit, that departure is sufficient to prevent
Process B infringing the patent in suit. In this connection, the proper approach
is that laid down by Hoffmann J in Improver, applying the reasoning
in the speech of Lord Diplock in Catnic Components Limited -v- Hill &
Smith Limited [1982] RPC 183 at 243. In Improver [1990] FRS 181
at 189, Hoffmann J said that, where "a feature embodied in an alleged infringement...
fell outside the primary, literal or acontextual meaning of a descriptive
word or phrase in the claim ("a variant")" then "the court should ask itself
the following three questions", and those questions ("the Improver
questions") were:
"(1) Does the
variant have a material effect upon the way the invention works? If yes, the
variant is outside the claim. If no-
(2) Would
this (i.e. that the variant had no material effect) have been obvious at the
date of publication of the patent to a reader skilled in the art. If no, the
variant is outside the claim. If yes-
(3) Would
the reader skilled in the art nevertheless have understood from the language
of the claim that the patentee intended that strict compliance with the primary
meaning was an essential requirement of the invention. If yes, the variant
is outside the claim."
The
addressee of the patent in suit
- It is convenient
to consider at this juncture the person to whom the patent in suit should
be treated as addressed. For the claimant, Mr Carr contends that it is a team
assembled by a chemical company, including a formulation scientist in the
agrochemical field and a physical chemist (i.e. essentially the two types
of expert witness called by each party). Mr Floyd argues for the defendant
that the addressee would be a formulation scientist in the agrochemical field
(e.g. Mr Knowles) and not a physical chemist (such as Professor Ryan or Professor
Luckham). The difference between the parties on this issue could be slight,
in the sense that, even if Mr Floyd is correct, it might nonetheless be that
his addressee, or the employer of his addressee, may think it right to consult
a physical chemist. However, the difference may be of some significance in
relation to the issues which I have to determine.
- In my judgment,
the contention on behalf of the defendant is correct. In Richardson Vicks'
Patent [1997] RPC 888 at 895, Aldous LJ said:
"There is no
basis in law or in logic for including within the concept of "a person skilled
in the art" a person who is not directly involved in producing the product
described in the patent or in carrying out the process of production."
- It cannot be
doubted but that the patent in suit is addressed to a formulation scientist
in the agrochemical field. Having considered the patent, in the context of
the technical background, which in the main is agreed, it seemed to me unlikely
that the addressee would also include a physical chemist, particularly in
light of what Aldous LJ said in the passage I have quoted. That provisional
view received support, in my judgment, from the evidence. In relation to the
main issue which requires to be determined, namely the meaning of "surfactant",
the relevant evidence on this point was as follows. Professor Ryan had never
been consulted about the practical side of operating a process for making
herbicides (apart from the instant case); Professor Luckham thought it unlikely
that he would be consulted on the choice of a surfactant; Mr Knowles said
he would not find it necessary to consult another chemist for the purpose
of deciding whether a particular substance was a surfactant. It was suggested
on behalf of the claimant that the addressee would include a physical chemist
because such a person would be needed to understand how the invention described
by the patent in suit works. I find that unconvincing: not only does the patent
in suit not describe how the invention works, but I do not see why it is necessary
to understand how it works in order to put it into practice.
- The view that
the addressee of the patent is a formulation scientist in the relevant field,
namely that of agrochemicals, and, indeed, that such a scientist would not
need to consult any other specialist is supported by a statement in the specification
upon which Mr Floyd understandably relies on behalf of the defendant. At page
3 lines 51-52, one finds this:
"The worker
of ordinary skill in the formulation art can select a surfactant most suitable
for the purpose in view."
- Perhaps rather
unusually, therefore, the draftsman of this patent has, at least for one purpose,
identified the type of addressee he has in mind and indicated that he is expected
to be able to act without having to consult experts in other fields. Of course,
that may not be conclusive, in the sense that such addressees might all agree
that they would need to consult an expert in another field; however, that
is not the case here. Further, the fact that one part of a patent appears
to be expressly directed to a specific category of expert does not necessarily
mean that the whole of the patent should be treated as directed to that type
of expert alone. However (1) the sentence I have just quoted from the patent
in suit is directed towards the selection of the surfactant, (2) the issue
in the present case is what is meant, and would be understood, by the term
"surfactant" and (3) it is common ground that expert evidence is appropriate
on that issue. Accordingly, it appears to me that the sentence is of significance
in relation to the question of the addressee of the patent in suit.
- Of the four
witnesses from whom I heard, it appears to me clear that Mr Knowles is closest,
possibly by quite a long way, to the notional addressee of the patent in suit.
Professor Hounslow, and the group which he heads at Sheffield University,
have particular expertise in granulation, but he very frankly accepted that
questions such as whether clay and starch are surfactants in the solid phase
was not something upon which he felt qualified to give evidence. Indeed, until
he was instructed in this case, Professor Hounslow had not been involved in
water-dispersible granules.
- The claimant
instructed Professor Ryan as an additional expert witness when it became apparent
that it might be somewhat vulnerable in relying on Professor Hounslow alone.
Nonetheless, Professor Ryan is not a formulation scientist, but a physical
chemist. In cross examination he accepted that he was "a very long way away
from the herbicide formulation scientist". Further, when discussing the way
in which the patent in suit was drafted, he said that he was "not sure that
the person who wrote the patent was approaching this problem in the same way
that I am approaching the problem...".
- Although Professor
Luckham has had contacts with the agrochemical industry, and has worked on
water-dispersible granules, he is not the sort of person to whom the patent
in suit is addressed. Indeed, Mr Floyd does not suggest that he does fall
within that category; he was called by the defendant essentially for defensive
purposes, when the claimant decided to call Professor Ryan in addition to
Professor Hounslow. At the priority date, Mr Knowles had been a formulation
scientist in the field of agrochemicals for 20 years. He has also been involved
with pilot and commercial scale operations. He gave evidence as to what he
and experts in the agrochemicals business understood by the term "surfactant",
and I see no reason to conclude that an agrochemical formulation scientist
of ordinary skill would need to consult a physical chemist as to what was
meant by "one or more surfactants" in Claim 1(a).
- As Mr Floyd
submitted, the notional addressee is an ordinary, albeit reasonably well qualified
and experienced, herbicide formulation scientist. While not suggesting that
Mr Knowles is, in any derogatory sense, "ordinary", it seems to me clear that,
particularly when compared with the other three witnesses, he is the only
one who could fairly be said to fall within that category. So far as the general
content of his evidence was concerned, it was internally consistent, as well
as being consistent with the evidence as a whole (although there were, inevitably,
differences of opinion and emphasis on various points between the expert witnesses).
His demeanour in the witness box and the way in which he dealt with the questions
put to him did nothing to displace my impression that he was a witness who
was doing his best to help the court rather than his client.
THE
FIRST ISSUE: THE MEANING OF "SURFACTANT" IN THE PATENT IN SUIT
Introduction
- As already mentioned,
the defendant contends that the word "surfactant", at least in the context
of the patent in suit, has a more limited meaning than that argued for by
the claimant. It is common ground that a surfactant works by reducing the
energy at an interface between two materials. The claimant contends that the
term "surfactant" extends to any molecule which is active at the interface
of two phases to modify the surface energy of the substrate, and whether something
is a surfactant depends upon the system in which it is used. The claimant
accepts that most surfactants are amphiphiles because they are used in the
presence of water, but that a surfactant does not have to be amphiphilic (or,
as it is sometimes called amphipathic), particularly if it is used in the
absence of water. The defendant contends that, at least in the context of
the patent in suit, the reference in Claim 1(a) to "one or more surfactants"
is limited to materials whose molecules are amphiphilic in nature.
- A number of
different factors were put forward in evidence and argument as being relevant
to the first issue. It can be dangerous to over-analyse or over-compartmentalise
the various possibly relevant factors advanced on an issue of construction;
it can involve the risk of not seeing the wood for the trees. However, it
is not really possible to do justice to the arguments or to explain the reasons
for reaching my conclusion on the first issue, if I do not identify, separate
and discuss the various different strands of the expert evidence and argument
which were advanced during the hearing.
- As Mr Carr pointed
out, the first step - that is the first of the four steps in Claim 1, i.e.
Claim 1(a) - which is referentially included in every subsequent Claim, requires
the addition of one or more surfactant. That is not an optional aspect of
the teaching; it is a mandatory aspect. The nature of the first issue between
the parties prompts the obvious question whether it is possible to discern
from the patent in suit, and, to the extent that it is admissible on this
point, from the expert evidence, the purpose of adding one or more surfactants
at the first step.
- The claimant's
case is that Claim 1 requires one or more surfactants to be added at the first
step in order to coat the material, and thereby to overcome the problem of
stickiness and melting, identified at page 2 lines 31-35 and page 3 lines
53-55 of the specification. The defendant, on the other hand, argues that
the purpose of adding one or more surfactant at the first step is to achieve
intimate mixing of the surfactant or surfactants (which, on this assumption,
are, of course, amphiphilic) so that the surfactant or surfactants operate
more effectively at the next stage, namely that described in Claim 1(b) of
the patent in suit ("the second step"). Each of these explanations is open
to attack.
The
reason for adding one or more surfactant: the claimant's explanation
- Three points
can be made against the claimant's interpretation. First, there is no relevant
teaching, indeed no suggestion of any teaching anywhere in the specification,
that deals with solving the "sticky propanil" problem. Indeed, the first passage
dealing with the problem mentions micro-encapsulation as a possible solution,
and the second passage simply asserts that "[f]low aids such as clays or silica
particles may be used to minimise these problems" and goes on to suggest certain
proprietary flow aids.
- The second problem
with the claimant's explanation as to why surfactant is added at the first
step is the claimed discovery at page 2 lines 45-47 of the patent in suit,
which appears to encapsulate the alleged inventive concept. It is "a process
for producing dispersible granule formulations" which have "good suspensibility
and dispersibility characteristics, and which resist attrition".
Thus, there is, at least in express terms, no suggestion of the discovery
involving a new method of overcoming the "sticky propanil" problem. The focus
of the alleged discovery is good suspensibility dispersibility and attrition
characteristics.
- Thirdly, if
the claimant is right, it is a little difficult to understand why the patent
in suit limits the substances which assist in the milling process to surfactants.
Even on the claimant's wider meaning of the word, there would be materials
which would assist in the milling of propanil which are not surfactants. This
was clear from Professor Ryan's evidence in cross-examination. The effect
of his evidence was that not all dispersants in the milling at the first step
are surfactants. If that is so, why, one asks rhetorically, did the draftsman
limit the materials added to the propanil at the first step to surfactants,
if their function is as contended for by the claimant.
- I do not consider
that it can be fairly contended that, because the specification mentions the
"sticky propanil" problem, it must be assumed to claim to solve it. Unlike
many patents, there is no contention, or even suggestion, in the patent in
suit that the alleged discovery overcomes all the problems identified in the
specification. Thus, there is no sensible way in which the patent in suit
can be read as even contributing anything new towards dealing with the "dust
problem" identified in the course of the passage at lines 14-23 on page 2
of the patent in suit: all that is said in that connection is at page 4 lines
12-13, which refers to "the preferred method of extrusion", as to which the
patent in suit contains no teaching or claims.
- This also impinges
on the possible explanation why, on the claimant's case, the materials at
the first step are limited to surfactants. It may be said that the innovative
concept, on the claimant's case, was the use of surfactants, as opposed to
substances which keep the milled propanil particles apart in some other way,
at the first step. If that were correct, one would have expected some express
suggestion, indeed some teaching, on that aspect. Yet there is none.
- The claimant
also suggests that, on its case as to the purpose of adding surfactant at
the first step, the surfactant is acting as a flow aid or as a dispersant
or as a disintegrant at that stage. I do not believe that is supported by
the terms of the patent in suit or, at least on my view, by the expert evidence.
- First, flow
aids. At least in the context of the specification, the contention that surfactants
are, or can include, flow aids, is not a happy one. As I have mentioned, at
lines 25-26 of page 3 of the specification, the draftsman tells one that "surfactant"
is used in the patent in suit "to include materials which may be referred
as emulsifying agents, dispersing agents and wetting agents". Further, in
the course of the specification, the draftsman appears to have been tolerably
careful in distinguishing between dispersing agents, wetting agents, flow
aids, defoaming agents and disintegrants. Obviously, as the draftsman plainly
contemplates, some substances can and will fall within more than one of those
categories, but I do not think that significantly detracts from the force
of the point.
- Although Professor
Ryan suggested in his evidence in chief that "one or more surfactants" were
added at the first step to assist the milling of the propanil, he accepted
that, when looking at the specification, this view is difficult to marry up
with the reference to "flow aids such as clays or silica particles" at page
3 line 54. As I have said, flow aids are treated as different from surfactants
in the specification (compare page 3 lines 25-28, explaining surfactants,
with page 3 lines 53-57, discussing flow aids). Indeed it was in connection
with this point that Professor Ryan said that he was not sure that the draftsman
of the patent "was approaching this problem in the same way that I am approaching
the problem..."
- The attempt
on behalf of the claimant to suggest that flow aids, at least as that term
is used in the patent in suit, can include surfactants runs into a further
difficulty. At least until they were instructed in this case, neither of the
claimant's experts, Professor Hounslow and Professor Ryan, had heard use of,
or had used, the term "surfactant" in relation to particulate materials in
the dry state; the flow aids referred to in the patent in suit are, of course,
such materials.
- As to dispersing
agents, it is true that the patent in suit states that "surfactant" could
include "dispersing agents" (page 3 lines 25-26). However, I do not consider
that this points to the conclusion that the addition of a surfactant or surfactants
at the first step was as a dispersing agent in an anhydrous dry medium to
keep the "sticky propanil" particles apart. Although both the claimant's experts
gave evidence which could be said to support this reading of the patent in
suit, I was not persuaded by it. The persuasiveness of their evidence on this
aspect was not assisted by the fact there was a difference between them. Professor
Hounslow described a surfactant as a material which "operates by energetic
interactions at an interface", whereas Professor Ryan thought that any material,
even if particulate, would be a surfactant if, at any rate for the purposes
of the first step, it kept the particles of propanil from agglomerating; according
to him, it would not matter how the material worked, whether it was particulate,
provided it performed this function it was a surfactant. On this basis, the
flow aids referred to in the specification were surfactants, and he accepted
that, on this basis, oil would be a surfactant as well. Indeed, even the micro-encapsulation
referred to at page 2 lines 31-35 of the specification would involve a surfactant.
On this basis also, as Mr Floyd points out, gas absorbing onto a metal surface,
indeed water absorbing onto propanil particles, would be a surfactant activity,
which suggest a far wider concept of surfactant than that envisaged by the
patent in suit, particularly in light of the evidence of Professor Luckham
and Mr Knowles.
- In his cross-examination,
Professor Luckham said that, at least in his view and experience, while a
material could be capable of acting as a surfactant other than in a liquid
phase, it could not act as a dispersing agent other than in a liquid phase.
He said that he would be surprised if people in industry thought of dispersing
agents as materials acting in anything other than the liquid phase. Mr Knowles
said that:
"Dispersing agents
are substances which absorb onto the surface of particles in aqueous media
and helped to preserve the state of dispersion of the particles preventing
them from reaggregating. ....Again it is clear to me from the patent that
the intention of [the draftsman] was to use the term dispersing agents in
this way."
- Further, Mr
Knowles knew nothing of the idea of powdered ingredients or particles acting
as dispersants in the dry state from his long experience in the agrochemical
industry. He agreed with Professor Luckham, and said that "they work[ed] from
a solution in water and only in the molecular state by absorption onto surfaces";
he immediately went on to correct that by expanding the reference to water
to "other liquids, but certainly not in the dry state". However, he went on
to say that, in the context of subject matter of the patent in suit, concerned
with water-dispersible granules, it was "inconceivable" that the liquid medium
"could be anything other than water". When dealing with what he understood
by dispersants or dispersing agents, he made what amounted to the same point.
In the context of the agrochemical industry, dispersants were understood to
be substances which acted in that capacity in "any liquid system, ... but
not a dry system" but he had "got [his] mind on the patent in suit, which
is an aqueous system".
- I have little
hesitation in preferring the evidence of Mr Knowles and Professor Luckham
on this issue. As already mentioned, of the four expert witnesses who gave
evidence in this case, I consider that Mr Knowles is the closest to the notional
addressee of the patent in suit.
- Quite apart
from this, the dispersion with which the patent in suit is concerned appears
to me to be dispersion in water, and that suggests that the dispersing agents
which the draftsman had in mind were dispersing agents in water, and, in my
view, they must amphiphilic. Indeed, that was accepted by Professor Ryan,
the claimant's expert physical chemist, when he said:
"I agree that
surfactants are needed for the purpose of enabling wetting of the milled propanil
and to disperse the final product when it is added to water. These surfactants
which function as wetting and dispersing agents must be amphiphiles."
- Although Mr
Carr nonetheless seeks to argue that, in the context of the patent in suit,
dispersing agents were not so limited, it seems to me that his argument (and
the evidence of Professor Ryan) faces a further difficulty from another passage
in the specification, at page 3 lines 42-43:
"In the context
of this specification a dispersing agent is a surfactant which facilitates
the dispersion of the pesticide particles when the product is added
to a liquid, for example water."
- I do not think
that the words "for example" assist the claimant in this connection, because
the only liquid mentioned in the specification, and the only liquid mentioned
in the claims, is water. Anyway, this passage fairly plainly limits dispersants
to those which act as such in liquids, not in the dry phase, as is involved
at the first step. Accordingly, the claimant's notion that the reference to
"one or more surfactants" in the first step is to one or more dispersing agents
which act as such in a non-liquid phase is inconsistent with the definition
of dispersing agent in the patent in suit itself.
- Before concluding
on the issue of dispersants and dispersing agents, it is right to mention
three subsidiary matters. Reference was made by Professor Hounslow to work
that had been done on the interaction of clay with sodium pentaborate. However,
they had only been studied in recent months, and cannot therefore conceivably
have been in the mind of the addressee of the patent in suit at its claimed
priority date. Reference was also made in the cross-examination of Professor
Luckham to dispersants with only hydrophilic ends, in the ceramics industry.
However, it seems to me that the course of that cross-examination is a good
illustration of how important it is to construe words in their context, in
this case the words "surfactant" and "dispersants" in the context of the patent
in suit. Two examples from the cross examination will suffice:
"Reasonable people
in this art may differ about whether types of dispersants are to be regarded
as surfactants?
In the surfactant
art, yes, but not in the agrochemical art.
...
Are you suggesting
that dispersant has a special meaning in the agrochemical industry?
No. I am suggesting
that it [means] something a bit different in the ceramics industry. ...
People in the
ceramics industry would not regard a dispersant as a surfactant because they
are not amphiphiles, whereas people in the agrochemical industry... would,
because there the materials they are using for dispersants are amphiphiles."
There was also
reference to titania particles which stabilised so-called Pickering emulsions:
that was not concerned with dispersing solid pesticides, but with stabilising
existing dispersions.
- I turn to the
suggestion of the claimant that a disintegrant could be a surfactant. For
the purpose of the patent in suit, it seems to me that the two concepts are
very different. First, disintegrants are not included in the type of substances
which are mentioned in the patent in suit as being within the category of
surfactants ("emulsifying agents, dispersing agents, wetting agents" - lines
26-27 page 3). Secondly, there is the observation that the recommended disintegrants
"have adverse effects on the propanil granules", a rather odd observation
if they were intended to be included as surfactants. Thirdly, the Example
on pages 10-11 of the patent in suit shows that the addition of increasing
amounts of specified disintegrants has an adverse effect on the beneficial
effect of a surfactant, as Professor Hounslow accepted. Further, disintegrants
are said to be "water soluble" (page 4 line 3 of the patent in suit); that
does not suggest that the draftsman had in mind materials which would be used
at the first step, which involves air milling and is anhydrous.
The
reason for adding one or more surfactant: the defendant's explanation
- The defendant's
explanation as to why the surfactant is added at the first step is, as I have
mentioned, to ensure that the surfactant is intimately mixed with the propanil
so as to enable it to perform its function at the second step. However, there
is no reference anywhere in the patent in suit to the need for intimate mixing
at the first step. That is true whether one looks at the specification or
at the Examples. Accordingly, there is obvious force in Mr Carr's point on
behalf of the claimant that the defendant's explanation as to the addition
of surfactant at the first step gets no support from anything in the specification
or Examples in the patent in suit, given that, on the defendant's construction,
the surfactant only operates at the second step.
- The claimant
also can derive some assistance from the fact that neither Professor Luckham
nor Mr Knowles said that, as at the claimed priority date, there was any perceived
problem at the second step which would be avoided by the intimate mixing of
propanil with a surfactant at the first step. However, Mr Knowles said in
his evidence:
"From my experience,
the purpose of what is taught in the patent, that is mixing and grinding the
surfactants with the active ingredient in a dry grinding process is to ensure
that a completely homogenous dry mixture has been obtained. Thus when water
is added prior to extrusion the surfactants are in intimate contact with active
ingredient particles and can prevent agglomeration of particles during extrusion
and drying. Both the wetting agent and the dispersing agent are often added
to the powder pre-mix before dry milling for this reason."
- He then went
on to expand on this in a little more detail both in his proof and in answers
to questions from Mr Floyd. He was cross examined about this view by Mr Carr,
but nothing which was put to him and nothing he said shook his evidence on
this point. Mr Carr correctly points out that the only documentary evidence
of any research suggesting the desirability of intimate mixing is in a book
edited by Mr Knowles, which was published in 1998. However, I have no reason
to think that the evidence I have quoted from Mr Knowles did not reflect what
was known to, and would have been appreciated by, the appropriately qualified
and experienced addressee as at the priority date.
- Mr Carr also
relied on some answers given by Mr Knowles in cross-examination which, he
suggested, showed a misunderstanding of Claim 1 in the patent in suit, because
Mr Knowles envisaged wetting agents or dispersing agents being added at the
second step, particularly if they were liquid, whereas the first step of Claim
1 made it clear that surfactants had to be added at that stage. I do not think
that is an entirely fair interpretation of Mr Knowles's evidence. To my mind
what he was saying was this. In so far as the dispersing agents or wetting
agents were liquid, they could not be added at the first step and would have
to be added at the second step. His evidence seems to have been to the effect
that some of the proprietary wetting agents identified in the specification
were liquids, whereas others were solids; however, all the dispersing agents
were solid. In those circumstances, as I read Claim 1 of the patent in suit,
in light of Mr Knowles's evidence that liquid surfactants could not be added
at the first step, any solid surfactant employed in the process described
in Claim 1 is required to be added at the first step, whereas any liquid surfactant
would be added at the second step. The absence of any reference to dispersing
agents at the second step is therefore explicable on Mr Knowles's evidence
by the fact that no liquid dispersing agents appear to have been included
in the examples, or were suggested by anyone in the evidence, so far as I
understood it. Further, the addition of an optional wetting agent is mentioned
at the second step, it is explicable by the fact that a liquid wetting agent
could not, as Mr Knowles explained, be added at the first step. In so far
as Mr Knowles's evidence was inconsistent with this conclusion, I do not think
he was right; however, it is fair to him to say that I do not read his evidence
as being inconsistent in this way.
The
specification: other indications
- It is inherent
in the forensic process that every aspect of the specification of the patent
in suit which appears to cast favourable light on a party's contention will
be put forward by its representatives as a factor to be taken into account
when determining the meaning of a Claim in that patent. That process can be
dangerous, not so much, perhaps, for the advocates, but for the tribunal deciding
the issue, because it inevitably involves careful consideration of every part
of the patent in suit, including the specification, which could be of relevance.
The process therefore encourages the court to adopt what Lord Diplock deprecated
as a "detailed semantic analysis" of the specification to see if one can tease
out of it features which appear to assist the resolution of the point in dispute.
While it is obviously right to construe the words of a claim in the context
of the whole of the patent in suit, including the specification, one must
avoid the trap of being too easily persuaded to invoke words in the specification
to cut down the natural and wide meaning of the words of the claim. Indeed,
that was the trap into which I fell in Cartonneries (unreported).
- In the present
case, it appears to me that the terms of the specification are of particular
significance at least in so far as they seek to define "surfactant" or to
indicate directly what the draftsman of the patent in suit had in mind when
using that term. Two passages are, in my judgment, of particular relevance.
The first is at page 3, lines 25-27, where, as I have mentioned, one finds
this:
"The term "surfactant"
is used in the broad sense to include materials which may be referred to as
emulsifying agents, dispersing agents and wetting agents and the surfactant
component may comprise one or more surfactants selected from the anionic cationic
and non-ionic type."
- Three points
may be made about this. The first is the fact that "surfactant" is expressly
stated to be "used in the broad sense". At least taken on its own, that suggests
that, if the word "surfactant" has a broader meaning (such as that, for instance,
intended for by the claimant) and a narrower meaning (such as that contended
for by the defendant) the draftsman has in mind the wider meaning. However,
one cannot stop with the words "broad sense". They must be seen in their context.
That brings me to the second point; the draftsman goes on to refer to the
fact that the term includes "materials which may be referred to as emulsifying
agents, dispersing agents and wetting agents". It is clear that all "wetting
agents" are amphiphiles. Initially, the claimant contended that not all "dispersing
agents" would be amphiphiles. However, it seems to me that, reading the patent
in suit as a whole, that contention cannot be right. For the reasons already
discussed, when the patent in suit refers to dispersing agents it is limited,
in my view, to amphiphiles (see especially the specification at page 3 lines
42-43).
- I have not so
far considered the effect of the reference to "emulsifying agents". I am bound
to say that that expression in the context of the patent in suit appears to
be somewhat mystifying. Mr Knowles said in his evidence that he regarded emulsifying
agents as surfactants which "emulsify oils into water and play a major role
in the stabilisation of pesticide formulations and impart good shelf life".
Two points can be made about that, both of which were expressed by Mr Knowles,
and which I accept. First, such emulsifying agents would be amphiphilic (because
again they are concerned with surfactant activity in water); secondly, they
are not relevant to the claims of the patent in suit because that is not concerned
with "forming emulsions [because] the particles are solid and not oily droplets",
to quote Mr Knowles again.
- The third point
to be made about the passage at page 3 lines 25-27 of the specification is
the statement that surfactants "may comprise one or more surfactant selected
from the anionic, cationic and non-ionic type". During cross examination,
Professor Ryan accepted that, even though, on his view, not every surfactant
was amphiphilic, any surfactant "selected from the anionic, cationic and non-ionic
type" would be amphiphilic. He accepted that "it would not be appropriate
to describe a surfactant which was not amphiphilic as being selected from
the anionic, cationic and non-ionic type".
- The other provision
of relevance in this context is at page 3 line 50 of the specification, where
it is stated that:
"All surfactants
act as dispersing agents to some degree and also to some degree as wetting
agents."
- As already indicated,
I am satisfied that, at least in the context of this patent in suit, all "dispersing
agents" and "wetting agents" are amphiphiles. If "all surfactants" within
the meaning of that expression in the patent in suit, act as dispersing agents
and as wetting agents, it must follow, in my judgment, that all surfactants,
as referred to in the patent in suit, are amphiphiles. As I have said, Professor
Ryan accepted that "surfactants which function as wetting and dispersing agents
must be amphiphiles".
- It is true that
Professor Hounslow appeared to suggest that this view may be called into question
in light of the use of the words "to some degree" but I am unpersuaded that
this takes matters any further. Some surfactants may act more effectively
as dispersing agents than as wetting agents, some may work more efficiently
as wetting agents than as dispersing agents, and some may not perform particularly
efficiently in either capacity. However, the words at page 3 line 50 appear
to me naturally to indicate that, when the draftsman refers to a surfactant,
he has in mind something which will act to some degree both as a dispersing
agent and as a wetting agent, which means that they must be amphiphilic.
Other cited
references to surfactants
- As is not uncommon
in a case involving issues such as the present, each party has referred to
definitions and uses of the word "surfactant" in published material available
at the priority date. Thus, in Atkin on "Physical Chemistry" one finds this:
"A surfactant
or surface-active agent is a species that is active at the interface
between two phases, such as the interface between hydrophilic and hydrophobic
phases. A surfactant accumulates at the interface and modifies the surface
tension."
- On the other
hand, in "Introduction to Colloid and Surface Chemistry" by Shaw, there is
this:
"The strong
adsorption on such materials at surface or interfaces in the form of an
orientated monomolecular layer (or monolayer) is termed surface
activity. Surface-active materials (or surfactants) consist of
molecules containing both polar and non-polar parts (amphiphilic)."
- Finally, I was
referred to the Royal Society of Chemistry's Handbook "Surfactants Europa"
which contains the following:
"Every surfactant
possesses the fundamental characteristic of having two essential portions,
one being water repellent, usually called hydrophobic (or lipophilic), the
other being hydrophilic (lipophobic)."
- While it would
be wrong to ignore definitions or uses of a particular word in text books
and other publications, it can obviously be dangerous to rely upon them in
a case such as this. The question which has to be determined is not what the
word "surfactant" means in abstract, let alone what it means in the context
of other publications directed to a different, or at any rate wider, class
of person than the person to whom the patent in suit is directed. The cases
to which I have referred emphasise the danger of trying to construe a word
or expression acontextually, that is outside the context of the patent in
which it is found. There can be even greater danger, I think, if one is seeking
to construe the meaning of a word in one context by reference to how it is
used in another context.
- Nonetheless,
where, as here, one party is seeking to give a word a significantly narrower
meaning than is suggested by the other party, some assistance may well be
found in passages such as those I have cited.
- The definition
of "surfactant" in Atkin is of some assistance to the claimant for two reasons.
First, it does not limit surfactant activity to the liquid phase; secondly,
it does not appear to limit surfactant to amphiphilic substances. However,
it is interesting to note that the one example given by Atkin is one which
would involve only an amphiphile as a surfactant, and would, I think, only
be likely to apply where one of the phases is liquid. Further, it does not
seem to me surprising that a term should have a substantially wider meaning
to physical chemists generally than it would have in the context of a specific
aspect of teaching in a patent directed specifically to the agrochemicals
industry. Quite apart from this, at least in the context of the patent in
suit, it is clear from the expert evidence that Atkin's definition would have
to be cut down by a functional qualification, namely keeping particles apart.
It is neither necessary nor appropriate for me to consider whether this qualification
should be imported into Atkin's definition. For all I know, the definition
may not need amendment, at least on one view of the meaning of "surfactant"
to physical chemists generally. I merely make the point in order to show how
a definition of a word in a text book may be too wide for the purpose of defining
how the word is used in another, more specialised, context, such as a patent.
- The definition
in Shaw is of help to the defendant. However, it can be said on behalf of
the claimant that the second sentence of the passage I have quoted from Shaw
may not have been intended to be exclusive. Even if that is right, however,
it does seem to me that the fact that a text book gives a narrower, rather
than a wider, definition of a word is of some assistance to the contention
that, when used in a specialist context, the word must have been intended
to have that narrower meaning. However, it would be wrong to suggest that
I think that that point, taken on its own, gets the defendant very far, particularly
in light of the definition in Atkin.
- The Royal Society
of Chemistry's publication is, I think, in principle, of rather greater assistance
than a text book, because it is intended to be a practical document, as is
the patent in suit, whereas a text book has a somewhat different purpose.
Mr Carr was able to point to Professor Luckham, who produced the extract I
have quoted from "Surfactants Europa", to one or two passages which rather
weakened the effect of the extract. In particular, there was the statement
that "there are many definitions of "surfactant" depending on personal preference
and field of usage". However, the extract referred to by Professor Luckham
is of some assistance to the defendant, in my judgment.
- In the end,
neither Mr Floyd nor Mr Carr places a great deal of weight on these definitions,
and, in my judgment, rightly. Nonetheless, they are of some limited assistance.
The
other Claims
- During the course
of argument, reference was made by Mr Carr to some of the other Claims of
the patent in suit, and in particular Claims 4, 5 and 10. Claim 4 narrows
Claim 1 (and Claims 2 and 3) to the extent of adding a dispersant at the second
step. Claim 5 is a variant in that it specifically involves the addition of
dispersant and flow aid at the first step, it involves a smaller particle
size at the first step, it involves adding less water at the second step,
it has a mandatory, rather than an optional, wetting agent at the second step,
and it requires the paste at the second step to be extruded. Claim 10 is a
variant on the preceding claims in that it requires the dispersible granule
to be "substantially free of disintegrant".
- While Mr Carr
places some reliance on the effect of these three later Claims to support
the claimant's construction of Claim 1, and in particular of the reference
to "one or more surfactants" in the first step, I do not find his arguments
convincing. His main point, at least in opening, was based on Claim 10. He
points out that the defendant's case is that disintegrants cannot be surfactants
for the purpose of the patent in suit in light of the passage at lines 3-8
on page 4 of the specification, which describes certain disintegrants as having
"adverse effects on the propanil dispersible granules". He argues that, given
that Claim 10 involves the addition of a disintegrant, the defendant's construction
cannot be right, and that it supports the view that a substance can be a disintegrant
and not a surfactant in one medium, such as water, but a surfactant in another
medium, such as the anhydrous air during the milling at the first step.
- First, it seems
to me that there is nothing in that argument which displaces the view that
the draftsman has distinguished between surfactants, which are desirable,
and disintegrants, which are undesirable, for dispersion purposes (compare
page 3 line 50 with page 4 lines 3-8 of the specification). Secondly, I consider
that Mr Floyd is correct in contending that Claim 10 has been included by
the draftsman for the normal reason, namely to protect the patentee if the
earlier claims are too wide. The draftsman has adopted the familiar scheme
of each successive claim being, at least generally, narrower than the previous
claim, with a view to giving a maximum potential protection for the patentee.
I do not see how the mere fact that the specific addition of disintegrant
in Claim 10 is of any real assistance to the issue of construction of Claim
1(a).
- So far as Claim
5 is concerned, it represents, as I have mentioned, really a narrowing down
of Claim 1 (and indeed of Claims 2 to 4) in a number of respects. As for Claim
4, at least if the defendant is correct, it is the first time that the problem
of "sticky propanil" has been addressed, namely by the express addition of
flow aid at the first step. Again, I do not see how they help on the issue
dividing the parties. On the claimant's case, flow aid could be within the
"one or more surfactants" at the first step of Claim 1, but it need not be.
On the defendant's case, flow aid might or might not be added at the first
step of Claim 1, but the draftsman has narrowed the ambit of the first step,
or, to put it another way, has been specific that flow aid has to be added
at the first step, when drafting Claim 5. In the same way the draftsman has
only specifically added a defoaming agent for the first time at Claim 4. Further,
the fact that the flow aid solution to one problem (which the specification
does not suggest is an inventive aspect of the claimed discovery) comes in
for the first time at Claim 5 is no more significant than extrusion coming
in for the first time at Claim 3.
The
expert evidence
- To a substantial
extent, I have already discussed the expert evidence relating to the first
issue in the preceding sections of this part of the judgment. Where, as here,
there is a dispute between the parties as to the meaning of a particular technical
word in a patent (or indeed in any other document), and each party leads expert
evidence to support its favoured construction, the net effect of that evidence
is often to confuse rather than enlighten. That is not meant to be critical
of such expert evidence in general, or of the expert evidence in this case
in particular. There are cases where an expert witness changes his mind, can
be shown to be proceeding on a false assumption, or can be shown simply to
be wrong. Where that does not happen, the court can be said to be faced with
the additional problem of resolving a dispute between reasonably credible
expert witnesses, in addition to having to resolve the centrally relevant
issue, namely the meaning of the word in question in the context of the particular
document in which it is found.
- Professor Luckham's
evidence was to the effect that the word "surfactant" was generally understood
in the field of physical chemistry as meaning an amphiphile. As Mr Carr said,
once one accepts that a surfactant must be an amphiphile, then the resolution
of the first issue between the parties is facile. In those circumstances,
unless "surfactant" must in all circumstances mean an amphiphile, and cannot
have the wider meaning contended for by the claimant, the rest of Professor
Luckham's evidence is of limited value: it puts the cart before the horse,
in that it decides what "surfactant" means generally and in the patent in
suit, and then proceeds to explain the patent in suit on that basis.
- Accordingly,
I regard Professor Luckham's evidence, in so far as it relates directly to
the meaning of the word "surfactant" in the patent in suit, as being of very
limited value. However, three further points should be made. First, as a physical
chemist, his view of the meaning of the word "surfactant" is of itself of
some significance. Secondly, as will be appreciated from observations made
earlier in this judgment, Professor Luckham gave useful evidence on various
other aspects, including the meaning of other technical words in the patent
in suit. Thirdly, as I have mentioned, Professor Luckham was not put forward
as the defendant's principal expert witness: he was an additional expert called,
as it were, to counter Professor Ryan, whom the claimant decided to call in
addition to its original expert witness, Professor Hounslow.
- Turning to the
evidence of Professor Hounslow, he was primarily concerned with the meaning
of the word "disintegrant" in the patent in suit. Having described the meaning
as "flexible", he, correctly in my view, went on to consider the meaning of
the word in the context of the patent in suit, and then turned to the question
of whether a disintegrant could be a surfactant. He had three or four years
working as a development officer for ICI's Australian operation in the early
1980s, but since then has held university posts. His particular expertise
is in granulation. Although I accept that he believed that, even in the context
of the patent in suit, disintegrants were, or at least could be, surfactants,
I consider that his evidence was of limited value, not least because, as Mr
Floyd argued, he is, and was at the priority date, far too skilled to be treated
as the addressee of the patent in suit. Furthermore, as I have also mentioned,
the reason the claimant decided to call Professor Ryan was because the question
of whether certain substances could be termed "surfactants" was not really
within Professor Hounslow's area of expertise.
- As to Professor
Ryan himself, I have already explained why he cannot fairly be said to be
the notional addressee of the patent in suit. I have also mentioned that,
at least in one important respect, he accepted that the draftsman of the patent
in suit did not appear to have approached the meaning of the word in the same
way as he does. His view as to the meaning of the word "surfactant", if approached
acontextually, was in accordance with the contention of the claimant, rather
than that of the defendant and its equivalent expert, Professor Luckham. It
is fair to say that, so far as his evidence in chief was concerned, Professor
Ryan appeared to approach the question of the meaning "surfactant" in the
patent in suit with a more open mind than did Professor Luckham. He concluded
that, in light of the passage at lines 25-28 on page 3 of the patent in suit,
the draftsman had used the word "surfactant" in the way in which Professor
Ryan would have understood it acontextually. However, as a result of his cross-examination,
I think that his evidence was as helpful, or as unhelpful, as that of Professor
Luckham. Each of them had a fairly clear idea as to what he thought "surfactant"
meant, and each of them approached the patent in suit with that thought very
much in mind.
- As with Professor
Luckham, the evidence of Professor Ryan was nonetheless of some help, taken
as a whole. In my judgment, Mr Floyd got further with Professor Ryan than
Mr Carr did with Professor Luckham, and I have in mind in particular the concession
by Professor Ryan, which I have already mentioned, that the draftsman of the
patent in suit did not appear to be approaching at least some of the technical
expressions in the same way as Professor Ryan would have done. Like Professor
Luckham, and indeed Professor Hounslow, Professor Ryan is not the sort of
person to whom the patent in suit should be treated as being addressed. At
best, each of them is the sort of person who might conceivably have been consulted
by the notional addressee, but, in light of the evidence of Mr Knowles (to
which I turn) and the way in which the patent in suit is drafted, I do not
think it likely that that would have happened.
- As I have mentioned,
Mr Knowles is within the scope of the notional addressee of the patent in
suit. Having explained the role of water dispersible granules in the agrochemicals
business, and the role of extrusion processes in that business, he proceeded
to describe what he understood the process described by the patent in suit.
He then went on to explain what he understood by the expressions "surfactants",
"wetting agents", and "dispersing agents", and explained why he considered
that the word "surfactant" in the context of the patent in suit was limited
to amphiphiles. It could be said that, in some respects, his testimony went
into areas on which evidence is strictly not admissible, but that is always
a danger in a case where expert evidence is admissible on a limited topic,
and it is fair to say that a similar point may be made in relation to the
other three experts. It should also be said that this is not intended to be
an adverse criticism of them as witnesses.
- However, dissecting
out the essence of Mr Knowles's admissible and centrally relevant evidence,
it seemed to me that, as a person representing the notional addressee of the
patent in suit, he was an honest witness, whose testimony as to how "surfactant"
in the context of the patent in suit would have been understood by the notional
skilled addressee was convincing. That evidence was to the effect that "surfactant"
would be understood to be referring to an amphiphile. As I have already mentioned,
it would be unfair to the claimant, and indeed on Mr Carr, to leave this topic
without mentioning that the expert evidence was not all one way. Although
they were not, by virtue of their disciplines and knowledge, as helpful witnesses
as Mr Knowles, Professor Hounslow and Professor Ryan did make some valid points,
and, as is probably clear from the earlier sections of this part of my judgment,
there are undoubtedly some factors which favour the claimant's case. Nonetheless,
principally because of his expertise and experience, Mr Knowles's evidence
was of more value than that of the other three expert witnesses. In sum, he
appears to have approached the issue in a helpful and correct way in his evidence,
and to have expressed a view on the central issue which was, in my judgment,
honestly held and reasonably convincing.
Conclusion
on the first issue
- With the exception
of the claimant's reliance on other Claims of the patent in suit, all the
other factors relied on by the parties appear to me to have some force. In
the end, while there are features of each factor upon which the claimant can
justifiably rely, it appears to me that the balance of advantage on each factor
lies with the defendant. So far as the body of the specification is concerned,
the claimant does get some assistance from the fact that the draftsman says
that the word "surfactant" is used in the patent in suit "in the broad sense".
However, the reference to surfactants being "dispersing agents and wetting
agents", particularly in light of the subsequent definitions and explanations
of those terms in the specification, significantly assists the defendant.
So too is the statement that the surfactant should be "selected from the anionic,
cationic and non-ionic type". The reference to surfactants acting as dispersing
agents, particularly in light of the definition and explanation of "dispersing
agents" in the patent in suit also supports the defendant's case.
- I consider that
the defendant's case is further assisted by the expert evidence. While not
in any way questioning the expertise of the other three witnesses, it appears
to me that Mr Knowles was the only witness who had the experience and discipline
of the notional addressee, whose identity is somewhat unusually expressly
suggested in the specification. He was an honest witness, whose evidence was
entirely consistent and stood up to cross examination. It would be unfair
on Mr Carr not to accept that he made some valid points to and about Mr Knowles,
but, viewing matters overall, they do not cause me to doubt his evidence as
to the understanding of formulation scientists in the agrochemical field of
the word "surfactant" and how that word would be understood at Claim 1(a)
of the patent in suit, namely as an amphiphile.
- The two text
books pointed in somewhat different directions, but, particularly when one
remembers the contents of the publication of the Royal Society of Chemists,
it seems to me that the balance is in favour of the defendant, albeit mildly,
on this score also. As I have already said, this is a comparatively minor
aspect.
- The question
as to why the surfactant is added at the first step is an important one, as
Mr Carr rightly says, because one is here concerned with the question of construction
of a document which is intended to have practical effect. If one confines
oneself, as a lawyer, to what is said in the patent in suit, then there is
considerable force in Mr Carr's point that it is difficult to discern the
purpose of adding one or more surfactants at the first step. For the reasons
already given, I am quite unpersuaded by the claimant's contention that it
is for the purpose of assisting at the milling stage. There is no teaching,
or even any claim to any discovery, to that effect anywhere in the patent.
On the other hand, in the absence of expert evidence, the idea that the purpose
is to assist intimate mixing of propanil and surfactant to optimise the second
step is the purest speculation, albeit not unreasonable speculation. However,
Mr Knowles, who seems to me to be close to the epitome of the notional addressee,
appears to have had no difficulty in understanding the purpose as being intimate
mixing, and while Mr Carr challenged him in cross-examination, and maintained
his challenge in his closing speech, I accept Mr Knowles's evidence on the
point.
- In all these
circumstances, I have come to the conclusion that the defendant succeeds on
the first issue, and, therefore, in order to be a surfactant for the purpose
of the patent in suit, a substance must be amphiphilic in nature.
THE
SECOND ISSUE: DOES PROCESS B INFRINGE THE PATENT IN SUIT?
Introductory
- As I have mentioned,
this question falls to be considered, irrespective of my conclusion on the
first issue. The defendant's Process B is confidential, and therefore I shall
only describe it to the extent strictly necessary for the purpose of explaining
my reasoning in relation to the second issue. Under Process B, propanil is
milled at the initial stage. The only material added to the propanil prior
to that milling stage are both or either of two proprietary substances marketed
as Paselli SA2 ("Paselli") and China Clay GTY ("China Clay"). Paselli is partially
hydrolysed potato starch, and China Clay is, as its name indicates, a naturally
occurring clay mineral deposit.
- On the defendant's
construction of the patent in suit, and in particular of the words "one or
more surfactants" in Claim 1(a), which I have accepted, a surfactant must
be amphiphilic in nature. Neither Paselli nor China Clay is amphiphilic, and
therefore their addition to the propanil at the first step of Process B does
not, at least on the face of it, involve the defendant infringing the patent
in suit. However, the claimant nonetheless contends that Process B infringes
the patent in suit, in that the addition of Paselli and/or China Clay at the
first stage, and the addition of surfactants at the second stage, of Process
B involves a variant which, on analysis, does not prevent Process B infringing.
If the
defendant is right on the first issue
- In the context
of this case, then, the variant between the allegedly infringing process and
the patent in suit is the use of a non-amphiphile in place of an amphiphile
in the first step, coupled with the use of an amphiphile at the second step.
In order to decide whether the claimant is right in contending that the variant
does not prevent Process B from being infringing, it is, of course, necessary
to ask the three Improver questions identified by Hoffmann J. I turn
to consider those questions.
- Does the variant
have a material effect on the way that the claimed invention works? Although
the evidence relevant to answering this question could have been more helpful,
I have reached the conclusion that the answer to the question is in the affirmative.
During the second half of 1995, in connection with opposition proceedings
in the EPO, and pursuant to a request from the EPO, the claimant carried out
an experiment, which it communicated to the EPO on 11th December 1995. That
experiment involved the preparation of three formulations. The first two formulations
involved milling propanil with chalk or clay, and then adding dispersants
with water. The third formulation (following the teaching of the patent in
suit) involved milling the propanil with clay and a dry dispersant, and then
adding water. The claimant then treated the formulations in the same way,
namely "mixing [them] to a consistency suitable for extrusion" and then extruding
them and drying them "in an identical manner". Having set out the results
in quantitative terms, the claimant justifiably described the result as "demonstrat[ing]
the unexpected advantages achieved by following the process of the [patent
in suit]".
- When this experiment
was put to Professor Hounslow, he said that he needed to know more details
of the experiments before he regarded them as helpful in connection with the
present case. However, he accepted that the second of the formulations in
the experiment was "very much akin to... Process B". He also accepted that
the result of the experiment showed not only "worse initial figures" for the
first two formulations as against the third formulation, but it also showed
relative deterioration in the products manufactured from the first two formulations
when compared with that from the third formulation. This, then, appears to
be evidence from the claimant's own experiment, to suggest that the answer
to the first Improver question is yes.
- The claimant
suggested that the fact that Process A and Process B both produce a saleable
product points strongly in favour of the answer to the first Improver
question being in the negative, because, of course, Process A does not contain
the variant in question. In my judgment, however, that will not do. The point
would obviously be powerful if it could be shown that the product of the two
processes was indistinguishable, but that was not the thrust of the claimant's
case. Even then, it would be conceivable that there was another difference
between the two processes which, as it were, cancelled out the difference.
I accept that that might be a fanciful notion, but, for the reasons I have
indicated, I do not have to consider it, because there is no evidence to show
that the products of the two processes are, in fact, identical.
- Accordingly,
I conclude that the answer to the first Improver question is in the
affirmative. That makes it strictly unnecessary to consider the remaining
two Improver questions, but, as they were fully argued, it is right
that I should do so.
- I turn to the
second question, namely whether it was obvious that the variant would have
no material effect. The principle expert witness whose evidence was relevant
on this point was Professor Ryan, one of the claimant's experts. While pointing
out that the question he had been asked in cross examination contained a double
negative he said that "it is not obvious to me that it [sc. the variant] will
not have any effect". I should say that the effect in question was the behaviour
of the pre-mix formed at the first step on the addition of water (and an optional
wetting agent) at the second step. In re-examination, he was a little less
sure, but the effect of what he said was that he was not sure whether there
would be a significant difference as a result of the variant, but he thought
that there probably would be.
- Further, always
remembering that I am proceeding on the assumption that the defendant's contention
on the first issue is correct, the purpose of including a surfactant at the
first step of Claim 1 of the patent in suit is to obtain intimate mixing of
propanil and surfactant or surfactants. On that basis, the variant involved
in Process B must have a material effect, virtually by definition. On the
face of it, that could be said to be an unattractive point given that, as
I have mentioned, there is nothing in the patent in suit which claims, or
even suggests a claim, to the effect that any aspect of its inventive concept
is involved in the intimate mixing. However, assuming that the reference to
"one or more surfactants" in Claim 1(a) is to one or more amphiphiles, then,
at the very least, the purpose of adding surfactants at the first step must
be to assist at the second step. Accordingly, adding Paselli and/or China
Clay, and not having any amphiphile, at the first step, as is involved in
Process B, would, at least on the face of it, be perceived as having a material
effect on the way in which the invention claimed by the patent in suit works.
Taken together with Professor Ryan's evidence, this satisfies me that the
answer to the second Improver question is no.
- I turn then
to the third question (which can only sensibly be considered on the assumption
that I have answered the first two Improver questions differently,
namely to the effect that the variant does not have, and would at the priority
date have been perceived as not having, a material effect upon the way in
which the claimed invention works). The third question is whether the appropriate
addressee would nonetheless have understood that the patentee intended that
strict compliance with the primary meaning was an essential requirement of
the invention.
- In my view,
there is force in Mr Floyd's contention that, if the defendant can show that
a narrower construction involves a patent claiming a process which is exclusively
novel, whereas a wider construction would extend to processes which are not
novel, that is a powerful argument in favour of the narrower construction.
I think that that submission derives support from what was said in Improver
itself at [1990] FSR 181 at 197.
- In this connection,
both the claimant's experts, Professor Hounslow and Professor Ryan agreed
that it was "extremely well known" that materials such as clay or silica were
useful in stopping particles sticking together in a dry milling process. However,
Professor Ryan agreed in cross examination that "the suggestion of using an
amphiphilic surfactant as a milling aid" was "rather interesting" and "quite
different from the old milling aids everybody knows about".
- In these circumstances,
if the Claim is limited to amphiphiles, the draftsman of the patent in suit
is identifying a category of materials with a particular ability to interact,
because of their chemical properties (its constituent molecules having one
hydrophilic end and one hydrophobic end) which had apparently not been suggested
for that purpose previously. On the other hand, if the Claim is treated as
not so restricted, the category will extend to materials which would interact
with the propanil in the same way as known particulate materials, with the
result that, albeit only to that extent, nothing new is claimed by the patent
in suit.
- It follows that,
in my view, the answer to the third Improver question is favourable
to the defendant, even if, contrary to my view, the answers to the first two
questions are favourable to the claimant. It also follows that, if the defendant
is correct on the first issue, as I have concluded, then it also succeeds
on the second issue.
If
the claimant is right on the first issue
- What if the
claimant is right on the first issue, and "one or more surfactants" in Claim
1(a) is a reference to any material which adsorbs onto the surface of particles
of another material (in this case propanil) and, as a result, keeps the particles
apart during the milling stage? In that event, a question, essentially one
of fact, has to be determined, namely whether Paselli and/or China Clay do
so adsorb, and keep the propanil particles apart during the milling. In this
connection, it is important to bear in mind that, as I have already mentioned,
flow aids of a particulate nature, which do not act by adsorption onto the
surface of, in this case, propanil were well known as at the priority date.
Accordingly, the question whether Paselli and/or China Clay work by adsorption,
that is by making use of an energetic surface interaction with the propanil,
is the central issue for this purpose.
- The evidence
relating to the action of Paselli and China Clay if and when added to propanil
at the mixing stage (i.e. at the equivalent of the first step) was not very
satisfactory, as both parties and their respective experts appear to agree.
Thus, in order to reach a reasonably confident conclusion, considerably more
research would have to be done than has been carried out so far.
- So far as Paselli
is concerned, Professor Ryan said that he would expect propanil to form H-bonded
complexes with Paselli, which would be driven by the reduction in surface
energies associated with the formation of such bonds. He said that, if that
was right, Paselli would be acting as a surfactant (at least on the claimant's
interpretation of that expression). He had carried out experiments with Paselli
in an aqueous system, but the results were such that he frankly said that
they provided no assistance for his view on the point. Professor Luckham expressed
"serious doubt" whether Paselli would act in the way described by Professor
Ryan in aqueous solution. As I understood him, he went on to explain that
if Paselli was unlikely to act as a surfactant in an aqueous phase, it was
even less likely to act as a surfactant in a dry, anhydrous phase, such as
is involved in air milling. This was essentially based on the fact that the
H-bond mentioned by Professor Ryan represented short-range interactions. He
went on to explain:
"In the solid
state the molecules are severely hindered in their motion [and] there is no
way that sufficient numbers of H-bonds could form to hold the Paselli on the
surface of the propanil."
- Professor Luckham
also explained that the roughness and thickness of particles would mean that
they only touch each other in a few places, and that that would further reduce
the prospect of any H-bond formation. He also took the view that, because
of its low vapour pressure, individual molecules of Paselli would be unlikely
to be able sufficiently to detach themselves from a solid Paselli particle
and attach onto, or be adsorbed onto, a propanil particle, to any significant
extent. Perhaps not surprisingly, Professor Luckham considered that Professor
Ryan's limited tests on the performance of Paselli in an aqueous system assisted
his view, and he went into a little detail to explain why.
- If the evidence
had stopped there, I would have held that the defendant had established that
Paselli did not act as a surfactant (even on the claimant's definition) at
the milling stage. The claimant, however, relied on the proposition that,
at the milling stage, propanil is likely to be molten, and that, in those
circumstances, particles of Paselli would adhere to the surface of the propanil,
as Professor Luckham accepted. I did not find the evidence of Professor Luckham
in cross-examination on that issue entirely easy to follow; that is not meant
as a criticism either of him or of Mr Carr, who cross-examined him. It was
largely due, I think, to the fact that Professor Luckham was answering questions
on the basis that "surfactant" meant something different from that which he
believed, and on the basis of the assumption, of which he did not know, that
the propanil was molten. Nonetheless, it seems to me that the effect of his
evidence was that, in agreement with Professor Ryan, (a) if the propanil was
molten at the milling stage and (b) if the term "surfactant" had the meaning
contended for by the claimant, then Paselli would act as a surfactant. Accordingly
and (in light of the weak nature of the evidence on the point) unfortunately,
the issue resolves itself into the question of whether the propanil becomes
molten during milling.
- There is obvious
force in Mr Floyd's contention that there is no evidence that propanil would
be molten during the milling process, particularly as the suggestion comes
from the claimant, whose only directly relevant witness, Professor Ryan, has
never inspected inside a mill. However, the teaching of the patent in suit,
whose validity I am assuming for the purpose of this preliminary issue, does
suggest that propanil becomes "sticky" when being milled. It is clear that
milling must increase the temperature of the surface of the propanil particles,
and that propanil has a comparatively low melting point. Bearing in mind my
conclusion on the burden of proof, I have, with real diffidence, reached the
conclusion that Paselli would act as a surfactant at the milling stage because,
but only because, the propanil would be sticky, as two passages in the patent
in suit suggest.
- I turn, now,
to China Clay. In that connection, the evidence of Professor Ryan and Professor
Luckham was, respectively, very similar to that in relation to Paselli. Thus,
Professor Ryan said that there would be "preferential adsorption of clay onto
the propanil particle's surfaces". Professor Luckham identified the same problems
with this view as he considered existed in relation to Paselli. He also said
that if China Clay did attach to propanil by H-bonding, it would raise the
surface energy of the propanil, whereas, in order to act as a surfactant,
it should lower the surface energy. While accepting the result, Professor
Ryan did not agree with the conclusion: he said that it was not a requirement
of a surfactant that it lowered surface energy. I have seen nothing to suggest
that, in order to be a surfactant, a substance must lower the energy of the
surface onto which it is adsorbed, and, I accept Professor Ryan's view, in
preference to that of Professor Luckham, on this limited issue.
- Some micro-photographs
were put in by Professor Ryan; his view was that they supported the contention
that clay acted as a surfactant (within the claimant's meaning of that word)
at the milling process. It would be unfair on the defendant to give much weight
to these photographs, bearing in mind that they were put in late, but they
do tend to support the claimant's case with regard to China Clay. In particular,
they tend to indicate that propanil particles may well be at least sticky,
possibly molten, a point which, of course, is not only relevant for China
Clay, but also for Paselli. It is true that, while the photographs suggest
that there is some adhesion between China Clay and propanil particles, they
do not show whether the China Clay is acting as a surfactant, even within
the wider meaning of that term adopted by the claimant. However, there was
a difference in the photographs between the way in which the China Clay and
propanil particles adhered together before, and after, milling. Further, the
cross examination of Professor Luckham indicated, at least to me, that if
China Clay did adhere to an extent to the particles of propanil, it was acting
as a surfactant, always assuming the wider meaning of that term as adopted
by the claimant.
- In the result,
while, as Mr Floyd rightly said, the evidence on this aspect of the case particularly
unsatisfactory, I have reached the conclusion that, if, contrary to my view,
the claimant is right on the first issue, it succeeds on the second issue.
It is right to add that I might well have reached a different conclusion on
this issue if the burden of proof were on the claimant.
CONCLUSION
- In these circumstances,
I conclude the preliminary issue in favour of the defendant. On the basis
that the reference to "one or more surfactants" in Claim 1(a) of the patent
in suit is to one or more amphiphiles, as I believe to be correct, Process
B does not infringe. If I am wrong and "surfactants" has the wider meaning
contended for by the claimant, then I would have concluded, with some diffidence,
that Process B does infringe. Subject to further argument, I think that it
follows that the defendant is entitled to a declaration that Process B does
not infringe the patent in suit.
