The Hon Mr Justice Kitchin:
Introduction
- This patent action concerns patient slide sheets. These are sheets used to reposition patients or transfer them from one surface to another, for example from bed to trolley to operating table. One surface of the sheet is suitable for engaging with the patient and the other surface is slippery and often covered with a low friction coating. The sheet is then folded over or sewn into a loop so as to form two inwardly facing slippery surfaces which engage with each other. The patient is placed on top of the folded or looped sheet and pushed in the required direction. The two inwardly facing surfaces of the sheet slide easily over each other so permitting the patient to be repositioned or transferred without having to be lifted.
- The claimant ("Select") claims to be the exclusive licensee of UK Patent No. GB 2 433 244 B. The second defendant ("Proto Magic") is the proprietor of the Patent. The application was filed on 13 December 2005 and the Patent was granted on 20 August 2008. It is a very short document with two claims, only the first of which is in issue in these proceedings.
- Select alleges that the first defendant ("Cromptons") has infringed the Patent by importing and selling a patient slide sheet called Poly-Glide. Cromptons denies that Select is an exclusive licensee under the Patent and also denies that Poly-Glide falls within its scope. It has counterclaimed for revocation for the Patent on the grounds of obviousness, insufficiency and added matter. In support of its allegation of obviousness it relies upon common general knowledge and the following two publications:
i) US Patent No 4,051,565 entitled "Mat Conveyor" published on 4 October 1977 ("Berge 2").
ii) US Patent Application No 2004/0172751 A1 entitled "Disposable Transport and Mat" published on 9 September 2004 ("Berge").
The expert witnesses
- Each side called one expert. For Select, I heard evidence from Mr Julian Ellis and for Cromptons, I heard evidence from Dr Peter Lofts.
- Mr Ellis has been employed in the textile industry for 43 years and for much of that time has specialised in technical aspects of yarn, fabric and garment manufacture. He is a Fellow of the Textile Institute. Cromptons suggested he lacked objectivity and was inclined to argue the case and that, as a result, I should treat his evidence with caution. I accept that Mr Ellis qualified some of his written evidence in the course of his cross examination but in my judgment he did no more than give ground when it was reasonable to do so in the face of questions put to him. On other occasions he maintained his opinions but I do not accept, as was suggested, that he was "on a mission to find infringement" or that he deliberately failed to address key issues. Overall, I believe he was doing his best to assist the court. I found him to be a knowledgeable and fair witness and his evidence was of considerable assistance.
- Dr Lofts is an expert in textile chemistry. He was in charge of research and development of nonwoven and related fibrous products for Johnson & Johnson from 1964 to 1987; Lantor (then part of the Tootal Group) from 1987 to 1992; and finally P&S Filtration from 1992 to 1996. He sat on the technical committee of EDANA (the European and Disposable and Nonwovens Association) and was for some time chair of the BNMA (British Nonwovens Association) technical committee. He retired from the textile industry in 2003. Dr Lofts gave his evidence in a careful, considered and entirely objective way, and I found it very helpful.
The skilled addressee
- The Patent is addressed to persons likely to have a practical interest in patient slide sheets. I therefore understand it to be addressed primarily to manufacturers and developers of such sheets and, in particular, to a team of persons with practical experience in the field of textile technology and the manufacture of woven and nonwoven fabrics. The team would also include somebody with practical experience of the use of patient slide sheets.
Common general knowledge
- The common general knowledge is all the knowledge which is generally known and generally regarded as a good basis for further action by the bulk of those engaged in the art to which the invention relates. It also includes all that material in the field in which the skilled person is working which he knows exists, which he would refer to as a matter of course if he cannot remember it and which he understands is generally regarded as sufficiently reliable to use as a foundation for further work or to help understand the pleaded prior art.
- The experts were largely in agreement as to the common general knowledge in this case. I begin with nonwoven fabrics. These are fabrics made of a web of fibres which has been strengthened by bonding using any of a variety of techniques such as chemicals, mechanical entanglement, plasticising solvents, or heat and pressure.
- One of the common ways of producing a nonwoven fabric is pin bonding. A web comprising thermoplastic fibres is passed between two heated rollers set very close to each other. One (the anvil roller) has a smooth surface. The other (the embossing roller) has metallic projections. These are called "pins" though they are not pointed. Instead, they have flat ends and their cross section is usually faceted, often in the shape of a diamond or square. In pin bonding, careful control of the temperature causes the sections of fibres pressed by the pins to fuse together. As they fuse, they shrink and lose much of their fibrous nature. The resultant regions are compact relative to the unfused areas and produce an overall dimpling effect on the fabric surface. Each dimple corresponds to a pin and typically has a diameter of about 0.6mm
- If the embossing roller is replaced by a smooth roller, the web is fused over all of its area. An example of such a web made of polyethylene is Tyvek. Nonwovens produced by smooth or pinned rollers are called "spunbonds", but only those produced by pinned rollers are called "pinbonds".
- There was also no dispute that the skilled person would have known:
i) of the existence and properties of commercially available spunbonds such as Tyvek;
ii) that spunbonds could be used in place of more costly woven materials for a broad range of applications in the medical field;
iii) that spunbonds (including pinbonds) could be fabricated into slide sheets for use in hospitals and elsewhere;
iv) that it was desirable to reduce friction between the sliding surfaces of slide sheets and this could be achieved by the use of lubricants such as silicone or a low friction, film-forming polymer such as polyethylene.
The Patent
- The Patent explains that patient slide sheets are commonly made from a woven material and are expected to have a life of years. However, to avoid cross contamination between patients, they must be washed each time they are used. Moreover, their cost is such that it is not cost effective to discard them after a single use.
- Against this background, the specification explains that the invention relates to the use of a nonwoven material to produce a patient slide sheet. The advantage of such a sheet is said to be that its cost is such that it can be used for one patient and then discarded. The specification continues:
"Non woven fabric is commonly produced from a plastic base material and can have various surface finishes such as smooth, pimpled, pin bonded or other effects. Some materials do not slide on themselves with a low co-efficient of friction. The friction in such sliding action can be reduced by adding a coating of silicone or other low friction material to the sliding surfaces."
- Claim 1 is in these terms:
"A flat patient slide sheet made from non woven material, one side of said non woven material having a pimpled finish and being coated with silicone or other low friction material, and said flat patient slide sheet being of such dimensions that it can be folded such that an area of the coated surface is in contact with another area of the coated surface and approximately half of the non coated surface is facing upwards, whilst the remainder of the non coated surface is facing downwards."
Construction
- It is well established that a patent specification must be given a purposive construction rather than a purely literal one. The question is always what the person skilled in the art would have understood the patentee to be using the language of the claim to mean. He reads the patent specification on the assumption that its purpose is both to describe and to demarcate an invention, that is to say a practical idea which the patentee has had for a new product or process. Further, it must be recognised that the patentee is trying to describe something which, at any rate in his opinion, is new; which has not existed before and of which there may be no generally accepted definition.
- There was no dispute that claim 1 of the Patent requires:
i) a nonwoven material with, on one side, a pimpled finish;
ii) the nonwoven material with the pimpled finish to be coated with a silicone or other low friction material.
However, the parties were unable to agree as to the meaning of either of these features.
- As for the expression "pimpled finish", both Mr Ellis and Dr Lofts agreed that this is not a term of art. Nevertheless, they both expressed views as to its meaning which at least served the purpose of articulating the parties' respective cases. Mr Ellis explained that, to his mind, the idea is that the frictional characteristics of the mating surfaces should be reduced by the inclusion of protuberances of some sort. He recognised that not every kind of protuberance will reduce friction. Accordingly, he said, the protuberances must have a size and smoothness and be distributed in such a way as to achieve a friction reducing effect.
- Dr Lofts, on the other hand, considered that the skilled person would understand that the pimpled finish should be deliberate and comprise protuberances having a generally circular base and a conical or cylindrical shape. Further, the protuberances must be distributed regularly over the entire surface, rise above a common surface and be discernible by the naked eye. But, he continued, the Patent provides no explanation as to why a pimpled finish, as opposed to a smooth, pin bonded or other effect or finish is desirable and the skilled person would consider the choice of a pimpled finish to be entirely arbitrary.
- In my judgment, it is clear from the body of the specification that the patentee was aware of a variety of nonwoven fabrics which were available at the date of the Patent including those which had smooth, pimpled and pin bonded surface finishes, some of which slide on themselves with a low co-efficient of friction. The particular wording of claim 1 indicates that the patentee has selected from amongst these possible finishes, and has chosen a pimpled finish. The skilled person would therefore recognise the pimpled finish to be an essential requirement of the claim and that the patentee has intentionally excluded a pin bonded finish from what is claimed. Subject to that, it seems to me that the interpretation favoured by Mr Ellis is broadly correct. I believe the skilled person would understand the expression "pimpled finish" to mean the surface of the nonwoven material must have an array of protuberances which rise above the common surface and, consistent with the purpose of the invention, promote friction reduction. But there is no reason to limit the expression to those having the precise geometric shapes described by Dr Lofts, nor is there any reason to limit it to protuberances which are discernible by the unaided eye.
- The second dispute concerned the meaning of the word "coated" and whether it extends to a very thin layer of low friction material which is mixed into the material said to have the pimpled finish, and then migrates to the surface. Select contended that the claim extends to any covering layer of low friction material irrespective of how it gets there. Cromptons argued that the claim requires a distinct manufacturing step which involves the application of the low friction material on top of the surface which has the pimpled finish.
- Once again, I prefer Select's interpretation. I recognise that the specification describes the addition of a coating of silicone or other low friction material to the sliding surfaces but the skilled person would appreciate that the claim is directed to a product rather than a process. He would also understand that the purpose of this feature of the claim is the provision of a covering layer which reduces friction. He would know this effect will be achieved by a suitable coating irrespective of how the coating is created.
Infringement
- The Poly-Glide product which is alleged to infringe is described in the Amended Product Description. It reads so far as relevant:
"The Poly-Glide single use slide sheet product code LP021-0003 is a flat patient slide sheet made from non woven polypropylene material, one side of said non woven material having a dimpled surface which is coated with low friction polyethylene material. The said low friction polyethylene material is comprised of a homogenous mixture of polyethylene and an additive."
- I heard evidence from Mr Martin Calhoun, the managing director of Cromptons, who explained to me that Poly-Glide is made in China at a manufacturing plant which he visited in March 2009. To the best of his knowledge, Poly-Glide is made from a sheet of nonwoven polypropylene material coated with low friction polyethylene which contains an additive. He therefore believes Poly-Glide to be a two layered product comprising a nonwoven sheet and a low friction coating comprising polyethylene and the additive. He has never asked for the product to have any additional layer and, to the best of his understanding, no additional layer has ever been applied. Further, he has never asked for the product to have pimples, pimpling or a pimpled finish and he does not understand the value of such a feature. During the course of his visit, he was shown a machine which he was told was used to apply the coating to the nonwoven polypropylene material. He could see that the machine had a row of spray nozzles situated just above a pair of rollers and a hopper containing material which was fed through the nozzles. The basic operation of the machine was explained to him. The nozzles sprayed a coating material on to one side of the sheeting which was fed between the rollers and then, in a continuous operation, onto a roll.
- Select's case on infringement has developed as these proceedings have progressed. On 4 November 2010 it served a statement of case in the following terms:
"The claimant states that its case of infringement is that it contends that the non woven fabric of the First Defendants' product is subjected to a finishing process which causes the non woven fabric to have a pimpled finish; the said pimpled finish arises before the coating of any silicone or other low friction material and that the finishing process comprises the addition of a high density polyethylene layer or layer of like material."
- Cromptons says that this case fails for two reasons: first, Poly-Glide does not have a pimpled finish; and second, no coating of silicone or other low friction material is added to what is said to constitute the pimpled finish. Poly-Glide only comprises two layers, namely the nonwoven polypropylene sheet which is pin bonded, and a coating of low friction polyethylene material which comprises a homogenous mixture of polyethylene and additive.
- In his second witness statement, Mr Ellis suggested that Poly-Glide has a second coating of paraffin wax, approximately 1 micron thick, which lies on top of the polyethylene. As I shall explain, this contention has now been abandoned in light of certain experiments carried out by Cromptons. However, in his third witness statement, Mr Ellis advanced a new allegation that the additive mixed with the polyethylene prior to its application contains an amide which migrates from within the body of the polyethylene after it has been applied to form a layer on its surface which may properly be described as a coating.
- Two issues therefore arise: first, whether Poly-Glide has a pimpled finish; and second, whether it is coated with a low friction material.
Pimpled finish
- Mr Ellis relied in his written evidence upon various photographs and micrographs of the Poly-Glide product; the photographs were taken with a Maplin lower power digital microscope and the electron micrographs using a focussed beam scanning electron microscope.
- The photographs taken with the digital microscope are exhibited to the second witness statement of Mr Ellis as JGE1. One was taken of each side of the sheet. The uncoated side is referred to as the "printed" side and is shown in photograph 1, and the coated side is referred to as the "unprinted" side and is shown in photograph 2. Mr Ellis focused on photograph 2 upon which he circled various areas which he said appeared to him to be pimples. I think it tolerably clear that two patterns can be seen in this photograph. One comprises a grid of dark shapes and the other comprises a second grid of diamond shapes with light edges which appears to overlie the first grid. The various areas circled by Mr Ellis comprise sections of these light edges.
- Some electron micrographs were also exhibited to the first witness statement of Mr Ellis and are comprised in JGE 1; others were obtained upon a repeat of Select's notice of experiments. In his witness statements Mr Ellis did not highlight any particular parts of these micrographs as revealing pimples, as he had with the photographs. However, in the course of his evidence in chief, he drew attention to 15 regions in four of the micrographs obtained on the repeat (X, tab 3, pages 1-4) which he also circled and suggested these were, or at least contained, pimples. When asked why he had not done this earlier, he responded that he thought they were self evident.
- Dr Lofts gave particular consideration to photograph 2 and the electron micrographs in his reply report. He explained that he could see no evidence of pimples on any of them. He was also rather puzzled by the grid patterns to which I have referred. He deduced that the dark shapes comprising the first grid had a width of approximately 0.6 mm and were caused by the pin bonding process whereas the diamond shapes with the light edges enclosed depressions with a width of only about 0.33 mm. He expressed the view that these must he the result of some other process and that the most likely candidate was an embossing process which took place immediately after the spraying of the polyethylene onto the pin bonded polypropylene sheet. Dr Lofts explained that this embossing process would involve passing the sprayed sheet through a second set of rollers whilst the polyethylene layer was still warm and semi-molten, and that one of these rollers would have an embossing pattern on its surface. This, continued Dr Lofts, would secure the coating onto the sheet, making the lamination stronger. In effect, such a process is similar to a pin bonding process and, like a pin bonding process, it produces dimples.
- When this theory was put to Mr Ellis, he agreed. The experts were therefore of one mind that the pattern on the unprinted surface of Poly-Glide is the result of two processes: first, the pin bonding of the polypropylene sheet; and second, the embossing of the polyethylene sheet onto the polypropylene sheet. In the course of his oral evidence Mr Ellis accepted these were similar processes and different from pimpling.
- As for the circled areas on photograph 2 and the micrographs at X, tab 3, pages 1-4, Mr Ellis maintained in cross examination that these were pimples because they were areas which were "raised above the general surface of the fabric". But he also accepted that they might simply be a consequence of the pin bonding or embossing processes.
- Dr Lofts was also cross examined about the areas which Mr Ellis had circled on the photographs and micrographs but, with one exception, was unable to identify any raised areas at all. He maintained that the surface was dimpled but not pimpled.
- I found the evidence of Dr Lofts very persuasive and, overall, I have reached the clear conclusion that Cromptons are correct on this point and that Poly-Glide does not have a pimpled finish as called for by claim 1. I reach this conclusion for the following reasons. First, the experts could see no evidence of the use of any pimpling process in the course of the manufacture of Poly-Glide. It was their common opinion that its appearance is attributable to pin bonding and embossing, both of which produce dimples rather than pimples. This is entirely consistent with the evidence of Mr Calhoun.
- Second, for the reasons I have given, the skilled person would understand that the patentee has selected a pimpled finish from amongst the other possible possible finishes, including those produced by pin bonding and other similar processes such as embossing.
- Third, I was wholly unpersuaded by Mr Ellis that the photographs or electron micrographs reveal anything that can sensibly be described as a pimpled finish in any event. On this issue, I preferred the evidence of Dr Lofts. The areas which Mr Ellis sought to characterise as pimples were simply regions around the outside of the dimples and, in so far as they may, on occasion, have risen very slightly above the common surface this was, as Mr Ellis accepted, very possibly the consequence of forcing the pins into the softened surface. This, I am entirely satisfied, does not meet the requirement of a pimpled finish as called for by claim 1.
- Finally, there was no evidence that the areas Mr Ellis described as pimples would have any friction reducing effect.
Low friction coating
- Select originally sought to establish the presence of a low friction coating by two experiments. I will address them in turn.
- Mr Ellis exhibited to his second witness statement an electron micrograph of a cross-section of the polyethylene layer of Poly-Glide (photograph 8 of JGE1) and suggested that this revealed a thin top layer approximately 1 micron thick. He thought this comprised a low friction material, probably paraffin wax. Dr Lofts was concerned by what he described as a "nebulous" image and accordingly Cromptons requested Select to carry out a repeat. This was done by Dr Christopher Parmenter at Nottingham University. It was witnessed by Dr Lofts who explained that it could not be repeated. Further, he explained that the cutting was carried out by a process called ion milling which tends to produce a "stepped" profile because material which is cut away is re-deposited at the cutting site. He concluded that there was no evidence of an outermost layer, or indeed of any structure whatsoever to the polyethylene film. I do not believe that Dr Lofts was ever effectively challenged upon this evidence.
- Mr Ellis was asked in cross-examination whether the cutting process might result in the re-deposition of degraded material at the cut site and agreed that that was a possibility. He was also asked whether the cutting process might produce a stepped profile and agreed that this too was a possibility. In light of this evidence of Mr Ellis and the firm opinion expressed by Dr Lofts I am satisfied that no weight can be attached to the electron micrograph upon which Select relied.
- The second experiment involved the use of a technique called X-ray photoelectron spectroscopy ("XPS"). This is a surface technique which probes the top layer of the surface of a material. The results of the XPS experiment were said by Select to show that the material on the surface of the unprinted side of Poly-Glide is paraffin wax. However, Dr Lofts pointed out that the conclusion was unfounded on the evidence and, indeed, contradicted by the results of the XPS experiment which revealed the presence of oxygen and nitrogen in the coated surface whereas paraffin wax contains only carbon and hydrogen. In his fourth witness statement, Mr Ellis accepted this to be correct.
- Nevertheless, faced with this experimental evidence, Cromptons carried out two sets of experiments itself. The first involved Fourier Transform Infrared Spectroscopy ("FT-IR"); and the second, Differential Scanning Calorimetry ("DSC"). In order to carry out these experiments Cromptons acquired samples of the raw material used to manufacture Poly-Glide and, in particular:
i) polypropylene pellets used to manufacture the nonwoven material;
ii) polyethylene pellets used to coat the nonwoven material;
iii) additive material pellets, which are mixed in and melted together with the polyethylene pellets prior to coating.
- There was no dispute as to the nature of FT-IR. It is a solid state technique which probes the top micron or so of the material under investigation and produces a spectrum or "finger-print" of the material being analysed. It was used to scan both sides of the Poly-Glide sheet and the spectra obtained were compared with the spectra of the raw materials. Dr Lofts explained that the FT-IR spectrum of the uncoated (printed) surface was consistent with the FT-IR spectrum of the polypropylene raw material, as expected. As for the coated (unprinted) surface, the FT-IR spectrum was consistent with the FT-IR spectrum of the polyethylene raw material and the library spectrum of polyethylene identified by the investigator's software. But it also contained a number of additional peaks not present in the raw material and library spectra. All these further peaks were, however, present in the FT-IR spectrum of the additive raw material. Three peaks, in particular, were consistent with the presence of an amide.
- Dr Lofts concluded that the presence of peaks corresponding to polyethylene and additive showed that they are all present on the surface of Poly-Glide and that the polyethylene is not completely covered with additive.
- Mr Ellis accepted in the course of his cross examination that these results showed that both polyethylene and the additive were on or near the surface. When asked whether or not this experiment established the additive did not form a coating, he responded that it depended on the thickness of the coating and how deeply into the surface the FT-IR technique penetrated, and this was not a subject upon which he had expertise.
- DSC is a technique used to study the thermal transition of materials on heating, and is ideal for observing the transition temperatures associated with polymeric materials. Samples are samples pre-weighed into an aluminium pan and crimped. This is then placed on top of a mini-heater within the DSC cell, with an empty pan being placed on the second heater as a reference. The sample and reference pans are then heated at a set temperature rate (in this case 10°C per minute) for the duration of the scan. The standard operating procedure ensures that the heating rate stays exactly the same throughout the experiment and, more importantly, ensures that the two separate pans heat at the same rate. When a transition occurs, for example, melting, the sample heater will have to input energy to ensure that it stays in equilibrium with the reference pan. It is this input of energy (or output in the case of an exothermic decomposition transition) that is measured in the DSC technique.
- The investigator used DSC to establish the melting points of the materials present on the two surfaces of Poly-Glide, and also those of the raw materials. As Dr Lofts explained, the melting point of the uncoated (printed) surface was 167°C, and that of the polypropylene raw material was essentially the same. The melting point of the coating on the unprinted surface was 128.9°C. The melting point of the polyethylene raw material was 110.7°C, consistent with its entry in the Merck index. That of the additive was 165.6°C.
- It can be seen that the melting point of the coating on the unprinted surface fell between that of the polyethylene raw material and the additive. It was therefore not consistent with the coating on the unprinted surface consisting of either of the individual raw materials but was consistent with a homogeneous mixture of the two. Dr Lofts was not directly challenged upon this evidence.
- Faced with this experimental evidence, Select's position developed and, in his third witness statement, Mr Ellis explained that although the additive, in the form of pellets, is mixed physically with the polyethylene and then the two are melted together, it was his opinion that the amide in the additive migrates to the surface of the melted product to form a coating so as to add a third layer on the surface of the product. Based upon the FT-IR data, he expressed the opinion that the additive contained erucamide and explained that this is a very common migratory slip agent.
- Mr Ellis was supported in this opinion by two papers written by Marvin Havens of the Cryovac Division of W R Grace & Co. The first, entitled Evaluation of Surface Concentration of Erucamide in LLDPE Films was published in the Journal of Vinyl & Additive Technology, June 2002, Vol 8, No 2 at 130. Mr Havens wrote:
"It is well known that additives are often required to modify the surface properties of polymer films (1-3). In a typical application, a prescribed amount of additive is compounded into a polymer and the compound extruded as a film. Over time the additive migrates and accumulates at the surface. For example, fatty amides are added in extrusion to reduce the co-efficient of friction for easier processing and handling of commercial film. Such fatty amide slip agents consist of a hydrophilic amide group on one end of a hydrophobic hydrocarbon chain. The dual nature of the fatty amide contributes to the additive diffusing or "blooming" to the polymer film-air interface.
In previous work using FTIR microspectroscopy, the concentration of erucamide across the thickness of compression-molded linear low-density polyethylene films was mapped. While the fatty amide is uniformly distributed throughout a freshly molded film, the additive segregates from the bulk and migrates to the surface over time."
- The second, entitled Inherently Static Dissipative Packaging Films, was published by Mr Havens at a symposium in 1991. It includes this passage:
"Plastic additives that provide antistatic properties are well known in the flexible packaging area. In a recent paper, the fundamental mechanisms for these traditional additives were discussed. In general, these additives are blended into or compounded with the plastic from which they exude or "bloom" to the surface over time. A "reservoir effect" is created by the additive amount and its modest affinity for the plastic matrix. Relative affinity is determined by the overall chemical similarity or molecular compatibility between the additive and the plastic. In addition to concentration and affinity, film thickness, additive volatility, etc., also affect the reservoir, the bloom rate and additive loss. Collectively, these determine the film's effective static dissipative lifetime."
- In the course of his cross-examination Mr Ellis maintained that the erucamide included in the additive mixed with the polyethylene to form the second layer of Poly-Glide does migrate to the surface where it forms a third layer.
- Mr Ellis was also asked to compare the DSC analysis of the additive and the unprinted surface of Poly-Glide. The DSC analysis of the additive revealed a component with a melting point of 82°C, consistent with the presence of erucamide. However, this was not present in the DSC analysis of the unprinted surface of Poly-Glide which, as I have said, had a melting point of 128.9°C. When it was suggested to Mr Ellis that this showed there was not enough of the amide for it to form a coating he did not accept that this was so. It was his view that it simply revealed that there was not enough of it for it to show up on a DSC analysis.
- Dr Lofts was also asked about the behaviour of the erucamide in the course of his cross-examination. It was put to him at day 2, page 296:
"Q. You have heard the theory that is put forward. The theory is that the additive blooms to the surface of the plastic that it is mixed with, howsoever it is mixed. We say that is what happens in this case. What do you say?
A. I think that is very probable."
- Dr Lofts also agreed with the explanation provided by Mr Havens as to how amide additives behave. Then, at page 306, line 7 to 307, line 20 he said this:
"Q. Do you or do you not think there is a layer of amide on the surface or are you simply not able to say one way or the other?
A. On the evidence of the literature and the XPS evidence, I would say there is additive of an amide nature in the surface.
Q. As a layer?
A. Well, it is a layer in molecular terms, not a layer in the sense of the film as we see it on the slide sheet material. We are talking of orders of magnitude lower. But yes, there is a layer of molecules of the additive.
Q. On the surface?
A. On the surface.
Q. You arrive at that conclusion because of your understanding of blooming?
A. Blooming, yes.
Q. Is that right?
A. Yes.
Q. What is the second matter that leads you to that conclusion?
A. That the x-ray photoelectron spectroscopy detected the presence of the elements of a group which was consistent with an amide.
Q. Why is that not equally consistent with it simply being present as part of an homogeneous mixture?
A. You cannot make the distinction.
Q. So that does not establish that there is a layer.
A. It does establish it is a layer. It depends whether you want to call a layer – if the entities composing the layer have to be continuous, if I scatter some [sand] over there but the individual grains did not touch each other, I think we could in common parlance say there is a layer of sand there, the particles would have to touch each other in order for it to be designated a layer. So the surface studded with the additive amide may have the molecules closely packed and continuous or they may not; but you might still want to call that surface layered with the additive…
Q. What would you call it?
A. I would call it layered with the additive."
- In my judgment the evidence of the experts on this particular point is consistent. Although the point emerged relatively late, I am satisfied that the additive includes an amide, probably erucamide, and this migrates to the surface of the polyethylene. Its purpose is to reduce friction and, in my judgment, it forms a coat, albeit a thin one. It follows that Poly-Glide is coated with a low friction material. This element of the claim is therefore satisfied.
Obviousness
- It is convenient to address the question of obviousness by using the structured approach explained by the Court of Appeal in Pozzoli v BDMO [2007] EWCA Civ 588; [2007] FSR 37. This involves the following steps:
(1) a. identify the notional "person skilled in the art".
b. identify the relevant common general knowledge of that person.
(2) Identify the inventive concept of the claim in question or, if that cannot be readily be done, construe it.
(3) Identify what, if any, differences exist between the matter cited as forming part of the "state of the art" and the inventive concept of the Claim or the Claim as construed.
(4) Ask whether, when viewed without any knowledge of the alleged invention as claimed: do those differences constitute steps which would have obvious to the person skilled in the art or do they require any degree of invention?
- I have identified the person skilled in the art and the common general knowledge earlier in this judgment. As for question (2), the inventive concept is defined in claim 1.
- That brings me to question (3). Berge 2 discloses tubular, disposable patient slide sheets described as tubular mats. It explains, in column 1, line 63 to column 2, line 11:
"The tubular mat is uniquely constructed of flexible material which preferably has a tough wear-resistant exterior surface engageable with the object to be moved and the undersupport therefor and preferably, presents relatively good frictional engagement with the object and the undersupport. The interior of the tube like mat is contrastingly provided with a slick or slippery surface, laminated, coated, impregnated or otherwise bonded over the interior of the tubular mat so as to present relatively friction-free opposing surfaces engageable with one another in the collapsed state of the mat. Movement of the object is accomplished by forcing the same laterally or transversely of the tubular axis of the mat so as to inter-engage the relatively friction-free inner surfaces and moving the same over one another, thereby to effect the desired transfer or transporting movement."
- Berge 2 does not specifically refer to nonwovens although, at column 3, lines 18-35, it refers to the use of plastic sheet material such as polypropylene, canvas, synthetic fibres, or the like, capable of providing a good wear-resistant frictional under surface which is productive of relatively good frictional engagement with the object of the mat's under support.
- Berge incorporates Berge 2 by reference and describes certain improvements including, in particular, the use of Tyvek as opposed to fabric. This is said not only to reduce the cost of material, but also to provide other options for assembly of the mat. It explains, at paragraph [0012]:
"Manufacturing is further simplified because both the inner and outer panels or surfaces of the transport mat may be made of the Tyvek material. Tyvek has a slick surface; therefore, a silicon spray is not required to provide necessary slickness of the interior surface. Nonetheless, Tyvek also readily accepts spray coatings of all types. Therefore, the inner surfaces may still be sprayed with silicon as desired, and the outer surfaces may be sprayed or coated with a thin film to increase frictional engagement…"
- Accordingly, the only difference between Berge and the inventive concept is the pimpled finish on the nonwoven material. This is the only possible invention disclosed by the Patent.
- That brings me to the crucial question, namely whether this difference constitutes a step which would be obvious to the skilled person or whether it involves any degree of invention. In assessing this question I must of course be wary of hindsight and this is particularly important where the invention is a simple one. As Laddie J said in Haberman v Jackel International Ltd [1999] FSR 683, at [29], the simpler a solution the easier it is to explain. The simpler it is to explain the more obvious it can appear. This is not always fair to inventors. Nevertheless, in my judgment the evidence on this issue is all one way.
- Dr Lofts referred in his report to the teaching of the Patent that nonwoven fabrics are commonly produced from a plastic base material and can have various surface finishes such as smooth, pimpled, pin bonded or other effects and he expressed the view that the skilled person would consider the choice of a pimpled finish to be entirely arbitrary. In the course of his cross examination he accepted that, although he knew of various pimpled materials and these formed part of the general knowledge, he was not aware of their use to reduce friction. However, the following matters also emerged. The skilled person would be aware that very smooth surfaces of, for example, polyethylene which are in intimate contact may adhere to each other and that in such a case it may be desirable to keep them apart. Further, if one were setting out to reduce friction, then one of the avenues to explore would be to consider the contribution made by pimples. In that regard he continued at page 283, line 18 to page 285, line 14:
"MR. JUSTICE KITCHIN: May I just ask, in connection with your last answer, do you think the skilled person would say that irrespective of the patent? In other words, without having read the patent.
A. Might very well do so, yes. Friction is taught in any number of schools and undergraduate courses and the notion that surfaces which we, at one level, regard as smooth are not smooth and have roughnesses and depressions and peaks. So I would expect people concerned with friction to have regard to that teaching, that common understanding.
MR. ROUGHTON: I am sorry, my Lord, I did not quite understand that. When you say "that teaching"?
A. That one should, when one is trying to understand what is happening when two surfaces move over each other, one is invited to think of going sub-microscopic into the fine structure of the material and to discover that there are peaks and toughs in the structure of almost everything. That is commonly taught. Certainly it was in my day. I can remember my physics master teaching me that. I had it rehearsed again when I was at university, so I am saying it is common knowledge.
MR. ROUGHTON: Thank you very much.
MR. JUSTICE KITCHIN: Would the skilled person understand that would prevent the very intimate contact of the kind that makes polythene bags stick together?
A. Yes. The skilled person would have that understanding.
MR. ROUGHTON: Would the skilled person know that in his mind or would one have to suggest, "Look, in order to reduce friction, you have got to have some degree of separation between the moving surfaces"?
A. I think, given the variety of human beings and what they know, you can find both examples.
MR. ROUGHTON: That is the problem, that we have one human being -- human person. If you cannot answer, so be it.
MR. JUSTICE KITCHIN: It is the skilled person in this field that we are talking about.
A. The skilled person in this field will know that causing surfaces to stand off from each other under right conditions of material and shape will reduce friction, yes."
- Then, a little later, he returned to this issue in response to a further question at page 301, line 21 to page 302, line 9:
"Q. I will not ask you to refer to that paper again. Can I take you back to one other thing, before we break off, which is that if you recall, you were asked some questions about the use of slide sheets with protrusions, call them pimples or raised areas, protrusions. One of the questions that you may want to ask yourself, if you wanted to reduce frictional effects, would be to somehow or other separate the two layers from each other in some way. Would you accept that as a fair summary?
A. Yes. One might well do that. It may be a lubricant, a fluid, or it may be a physical arrangement of the surfaces.
Q: You say it may be a physical arrangement of the surfaces?
A. i.e. things like pimples or other asperities."
- Dr Lofts was therefore very clear that the skilled person would have known that separation of two smooth layers would reduce friction between them and this separation could be achieved by the physical arrangement of their surfaces, including the use of pimples.
- Mr Ellis said in his third witness statement that pimpling is likely to give improved properties over Berge and that this was a non obvious approach. However, in his evidence directed to sufficiency, he explained that it would be a relatively simple matter for a skilled person to add a pimpled finish to a thermoplastic surface, and to achieve a satisfactory level of pimples through simple experimentation to arrive at a working slide sheet. He also said that the reason for using pimples in the patented invention was clearly to reduce friction.
- Further, in response to a question from the court in the course of his oral evidence, Mr Ellis painted a very different picture as to whether the idea of a pimpled finish was obvious (at page 187, line 12 to page 188, line 6):
"MR. JUSTICE KITCHIN: Does it come down to propositions which are as simple as this? You described to me yesterday that anybody knows, and certainly somebody interested in fabrics knows, that if you have a very smooth surface facing another very smooth surface, they can tend to stick ----
A. Umm hmm.
Q. -- just like plastic bags that we, in everyday use, have to open. If you were to put some sort of pimply surface, that might assist to prevent that happening.
A. Yes, because there would be more air between the surfaces of the bag.
Q. That would be self-evident to anybody in this field?
A. Yes.
Q. Just like it would be to a member of the public?
A. Yes.
Q. You say then, to put such a surface on to a sheet would be something which somebody in this field would have absolutely no difficulty in doing?
A. Yes."
- The experts were therefore of one mind. It was obvious to separate the layers by the use of protrusions or pimples. It follows that claim 1 is obvious over Berge and Berge 2.
Insufficiency
- Cromptons argued that the specification of the Patent does not disclose the invention clearly and completely enough for it to be performed by a person skilled in the art. Specifically it alleged in its pleaded case that if the claims of the Patent are construed to cover products in which the pimples are microscopic in size or sufficient in number, distribution and smoothness in order to produce the effect of friction reduction then, at the date of filing of the application for the Patent (13 December 2005), the skilled person could not have produced such a material as the Patent does not disclose how to create or apply the pimpled finish, nor how to select or obtain the correct size, number, distribution or smoothness of the pimples on the pimpled finish in order to produce the effect of friction reduction or ascertain whether a particular product falls within the scope of the claim.
- It is well established that the teaching of the specification must be sufficient to allow the invention to be performed over the whole scope of the claim. The specification need not set out every detail necessary for performance. The skilled man may be left to use his own skill to perform the invention and may be expected to carry out routine trials. In doing so, he must seek success. But he should not be required to carry out any prolonged research, enquiry or experiment.
- As the case developed, Cromptons suggested that the Patent fails to describe at least one way of carrying out the invention and leaves the skilled person to carry out experiments to ascertain the friction reducing characteristics of pimples and how to produce a satisfactory surface. This, it said, is a classic case of setting the skilled person a puzzle and calling it a specification.
- I rather think this argument was advanced by Cromptons as a squeeze, that is to say, if the Patent is not obvious then it must be insufficient because it contains no teaching of the purpose of the pimples or how they are to be made or arranged. Be that as it may, I am satisfied on the evidence that the skilled person would be able to implement the invention the teaching of the Patent without undue effort. It was suggested to Dr Lofts that the skilled person could adjust a number of variables such as pressure on the rollers and the temperature of the material. He agreed that a series of experiments would come to mind and that adjustment of various manufacturing conditions could be used to produce pimples and this would be "common sense". Mr Ellis too thought this was something the skilled person would have no difficulty in doing.
- The allegation of insufficiency therefore fails.
Added matter
- The added matter allegation is advanced as an alternative to the obviousness allegation. Cromptons contended that if pimpling is an inventive step over Berge on the basis that it is likely to give improved frictional properties then this is not disclosed in the application for the Patent and constitutes added matter.
- The test for added matter was explained by Aldous J in Bonzel v Intervention [1991] RPC 553 at 574:
"The decision as to whether there was an extension of disclosure must be made on a comparison of the two documents read through the eyes of a skilled addressee. The task of the Court is threefold:
(a) To ascertain through the eyes of the skilled addressee what is disclosed, both explicitly and implicitly in the application.
(b) To do the same in respect of the patent as granted.
(c) To compare the two disclosures and decide whether any subject matter relevant to the invention has been added whether by deletion or addition.
The comparison is strict in the sense that subject matter will be added unless such matter is clearly and unambiguously disclosed in the application either explicitly or implicitly."
- The essential task for the court is to consider the disclosure of the application and the Patent and to ask whether any subject matter relevant to the invention has been added.
- I can deal with this allegation very shortly in light of my finding on obviousness. The application describes the invention in the same way as the specification of the Patent. It also includes a claim to a patient slide sheet made from nonwoven material where the sliding surfaces are pimpled. The disclosure of the application and the Patent are therefore the same. No subject matter has been added.
Exclusive licence
- I have found the Patent is invalid. Therefore it is not strictly necessary for me to decide whether Select was ever granted an exclusive licence. Nevertheless, since I heard evidence and argument on the point, I will express my conclusions.
- An exclusive licence is defined in s.130(1) of the Patents Act 1977 in these terms:
""Exclusive licence" means a licence from the proprietor of or applicant for a patent conferring on the licensee, or on him and persons authorised by him, to the exclusion of all other persons (including the proprietor or applicant), any right in respect of the invention to which the patent or application relates, and "exclusive licensee" and "non-exclusive licence" shall be construed accordingly."
- Select's pleaded case is that it was granted an oral exclusive licence under the Patent on 23 July 2005 in the course of a face to face meeting attended by Mr Dale and Mr Ponting, the inventors and directors of Proto Magic, and Mr Paine, a director of Select.
- Both Mr Dale and Mr Paine gave evidence before me. Their witness statements appeared to confirm Select's pleaded case. However, it became clear in the course of their cross examination that they had no recollection of a specific meeting on 23 July 2005 and no explanation for the fact that this alleged meeting took place some five months before the application for the Patent was filed. Nor could they provide any explanation for the terms of a letter written by Mr Ponting to Mr Paine dated 8 January 2010 in which he referred to Select as Proto Magic's "sole licensee".
- In these circumstances Cromptons submitted that Select's case that it was granted an exclusive licence had simply not been made out. However, in the light of the evidence as a whole, I have come to the conclusion that there was indeed an agreement between Select and Proto Magic whereby Select was granted the exclusive right to exploit this Patent and other developments made by Proto Magic in return for the payment of royalties. Neither party was familiar with patent law or the importance of committing their relationship to writing. These were businesses run by practical men but they had a clear understanding that they had an agreement established over many years of dealings with each other that Select had the exclusive right to make and sell products developed by Proto Magic including, after the filing of the application, those covered by the Patent, in return for a royalty on sales. In the case of the Patent, the first sales of Select's product called Supa Slide were made in about January 2006 and royalties have been paid ever since. Mr Paine was not familiar with the term "sole licence" but he had no doubt that Proto Magic had agreed that Select was the only company entitled to work the Patent. Mr Dale's evidence was to like effect. He believed that Proto Magic had no right to make or sell products falling within the scope of the Patent because it had agreed that Select was the only company allowed to do so.
Conclusion
- It follows:
i) Poly-Glide does not fall within the scope of claim 1 of the Patent; and
ii) the Patent is invalid for obviousness.
- I will hear argument as to the precise form of order if it cannot be agreed.
