Strand, London, WC2A 2LL
B e f o r e :
| (1) MVF3 APS (FORMERLY VESTERGAARD FRANDSEN A/S)
(2) VESTERGAARD FRANDSEN SA
(3) DISEASE CONTROL TEXTILES SA
|- and -
|(1) BESTNET EUROPE LIMITED
(2) 3T EUROPE LIMITED
(3) INTECTION LIMITED
(4) INTELLIGENT INSECT CONTROL LIMITED
(5) TORBEN HOLM LARSEN
(6) TRINE ANGELINE SIG
Martin Howe QC and George Hamer (instructed by McGuireWoods London LLP) for the First, Second, Fifth and Sixth Defendants
Hearing dates: 22-24 February 2011
Crown Copyright ©
MR. JUSTICE ARNOLD :
|Proceedings at first instance||4-26|
|Proceedings in the Court of Appeal||27-37|
|The effect of the Court of Appeal's order dated 24 November 2010||43-60|
|Should VF have disclosed the Documents before?||61|
|The role of the expert evidence at this hearing||62|
|Professor Stevens' evidence||63-68|
|Should an adverse inference be drawn from VF's failure to call factual witnesses?||69-70|
|The PCT Application||71-90|
|Z617 trial (October-November 2006)||93|
|R3 trial (December 2006-January 2007)||94-97|
|R4 and R7 trials (February-March 2007)||98-113|
|R12 trial (May 2007)||114-123|
|R15 trial (June 2007)||124-127|
|R16 trial (June 2007)||128|
|R25 trial, Phase 1 (October 2007)||129-132|
|R25 trial, Phase II (May 2008)||133-135|
|R25 trial, Phase III (July 2008)||136-138|
"There be remitted for determination by the Chancery Division before Arnold J the following questions of fact, namely:
(i) how strongly the migration rate of deltamethrin is affected by the addition of LDPE to the polymer mix;
(ii) how that effect (if any) compares to the effect of the three additives referred to in paragraphs 121(i)-(iii) of the judgment of Arnold J dated 3 April 2009;
(iii) whether the outcome of issues (i) and (ii) above renders the Fence results not useful for the formulation of the Defendants' product."
Proceedings at first instance
"3. This report will show that in my professional opinion the information used to achieve the Netprotect product could all have been obtained from the public domain and from industrial information sources which are not secret. Such information is made available by both polymer and additives manufactures [sic].
4. I conclude that the two products are significantly different in respect of the polymer blend used, the additives and additive concentrations used, the absence of certain additives in the Claimant's product which only appear in Netproduct including the [ADDITIVE M] processing additive which enables the polymer melt to be extruded at lower temperatures. I consider the final Netprotect product to be an independent development and one that has distinct process differences to that of the Claimant's product.
5. I further conclude that it is possible that the experience and knowledge gained by the Defendants when working for the Claimant may have contributed to the selection of additives in the early exploratory phase of the Netprotect development. However, it is clear that this same starting position could have been obtained from the public literature and that the final product developed is significantly different to both the Claimant's product and the initial trial materials produced by the Defendant's [sic] in their own development. I conclude the final product developed by the Defendants is original and of independent design."
"The benefits of plastics additives are not marginal – they make the difference between success and failure in plastics technology."
"75. The interaction between insecticide in the polymer matrix is complex and difficult to predict. A change in the polyethylene matrix will make a big difference to the retention and migration of the insecticide within the polyethylene. The complexity relates to the change in the matrix acidity that the insecticide may introduce, which may affect polymer degradation, and to insecticide induced changes in crystallisation behaviour and morphology development from the melt following extrusion all of which may affect insecticide retention and loss rates. Insecticides may also interfere with the action of polymer additives and additives may also confer protection to the insecticide, such as improving heat stability and reducing the potential for oxidation.
76. Laboratory and experimental studies have explored relations between host polymer, insecticide, formulation, dosage, and effect. Durability also varies for different polymer hosts. The role of additives and polymer morphology in assisting the dispersion, retention and appropriate release of the insecticide are therefore key factors and it is clear that this is a poorly understood area where more research is needed is a design approach to formulation is to be adopted in the future. In most cases reliable formulations at [sic] arrived at by trial and error following initial guidance from polymer and additive manufacturers with experience in related applications (e.g. agricultural films)."
"The bases [sic] polyethylene compositions of the VF and Netprotect products are very different. The Fence recipe 65.F.0 304.5 gives a polyethylene matrix that is [REDACTED]% HDPE, [REDACTED]% LDPE with the balance in additives. The Netprotect recipe [NPT details.doc] provides a polyethylene matrix that is [REDACTED]% HDPE, [REDACTED]% MDPE, [REDACTED]% LLDPE, [REDACTED]% LDPE, with the balance in additives. These are very different polymer compositions which require different additive combinations."
"47. Polyethylene is a simple polymer chain that can pack in a variety of different ways, dependent on the side groups attached to the chain. These prevent the chain 'packing' in a regular manner - crystallisation - and leave room for small molecules to impregnate these voids. The polyethylene is a mixture of tightly packed crystallites and amorphous regions, with high-density polyethylene being the most densely packed (density greater than 941 kg/m3 - giving high tensile strength), medium density polyethylene being intermediate (density between 926 and 940 kg/m3 - good stress crack resistance), and low density polyethylene being much less densely packed (density between 910 and 925 kg/m3 - good stress crack resistance). …
48. The polyethylene blend composition has a profound effect on the retention and storage of the active ingredient in the final product. The additives will tend to be excluded from the crystalline parts of the polyethylene and will segregate to the less ordered and amorphous phase. It is the form and distribution of the crystalline phase in the amorphous phase (the so-called microstructure) that affects the distribution, entrapment and movement of the additives in the polymer matrix. The arising microstructure will be influenced by both the precise nature of the polymer blend and also the nature of the additives and active ingredients present in the hot polymer melt before extrusion and cooling.
49. The rate of release of additives from the polymeric material will be controlled by the distribution of these crystalline and amorphous phases, and their connectivity. This distribution is particularly sensitive to the temperature and mechanical processing of the polymer but also by the type and concentration of the additive."
"63. Within a range of PE materials, migration rates would be expected to increase as the density of the PE material decreases, as the degree of crystallinity reduces and the free volume of the material increases (LDPE can be thought of as having a more 'open' structure than HDPE). …
364. … Furthermore, I would expect the addition of LDPE [to samples in the Defendants' October 2004 trials] to open the structure of the material slightly and increase the migration rate of the insecticide. …
513. … Both the reduced deltamethrin content and the removal of LDPE [in the Defendants' 'test i marts 2006' recipes] would be expected to slightly reduce the migration rate, potentially counteracting the [ADDITIVE C] reduction."
"119. … The results of a linear regression analysis on the Netprotect 'Screening round 2' samples are shown in Tables 3, 3b, 3B and 3C of the Defendants' disclosure document 137 [S5/1456-1458]. The conclusion drawn in this document is that 'only the impact of [ADDITIVE C] is sure'. The analysis does not show that LDPE has an overriding effect on wash test performance.
120. I agree with OS that the migration performance of insecticide-incorporated PE nets will be affected by the base polymer type used. However, the additives do influence the migration of insecticide as described Section 3.3.3 (starting at page 64) of my First Report [K/1/64-70].
121. At the end of paragraph 152 of his Seventh Witness Statement [D/6/131], OS refers to test conducted in Benin where 'two identical formulations were tested with and without extra MDPE and LDPE [see pages 65- 68 of OS7]'. However, from the information contained in pages 65-68 of exhibit O7 [E/5/335-337], it is not clear what the formulations of the samples are. Therefore I can make no comment on the performance of these samples."
"Q. If you then change the plastic as well, the polymer, because it is for a different purpose, one is for a bed net an[d] one is for a fencing net, you might want to have a different mix of polymers.
A. Yes. If you check, it is not different like if you change from polyethylene to polyester or polypropylene to propylene but even in polyethylene they are different, many time different grades. So of course when you change the diameter, the process, we would look for the best performance polyethylene, the same polyethylene but different grade, so we call it like more optimizing.
Q. So that changes the nature of the net because it may be softer for a bed net but it also changes the whole characteristics of migration within the plastic, does it not?
A. It is; changes the migration to some extent."
"I find that, when devising the initial recipes for Netprotect, Dr Skovmand started from the Fence formulations which had been bioassayed and found to give good results, namely samples 7-16 and in particular samples 8, 9 and 13. … He expected success with one of these formulations, or a variant of those formulations."
"604. (3) It was said that the reason why Netprotect was successful was not due to its additives, but due its polymer composition and manufacturing process. In particular, the Defendants relied on the contention that Netprotect contained LLDPE and MDPE, but the Fence samples did not, enabling a lower extrusion temperature to be employed. As to this, the evidence not only of Mr Howe but also of the Defendants' expert Professor Stevens was that additives play an important role in polymer processing. Thus in his report made in support of the Defendants' application to strike out the claim Professor Stevens said:
'The benefits of plastics additives are not marginal – they make the difference between success and failure in plastics technology.'
Furthermore, it is clear from the evidence in this case that the choice and concentration of the additives makes a difference to the performance of the product, in particular so far as migration of deltamethrin is concerned.
605. I accept that polymer composition and manufacturing process are also relevant factors, but as discussed above the Defendants' production runs of Netprotect have not always included LLDPE or MDPE, or even LDPE. I would also observe that the Netprotect database shows that, contrary to the Defendants' claim to employ an extrusion temperature of [TEMPERATURE 3], the more recent samples were extruded at [TEMPERATURE 4]. In any event, however, I consider that the relevance of these factors is not to the question of the source of the early Netprotect recipes, but to another issue which I will consider below."
"(4) It was said that the migration rate was strongly affected by the polymer composition and so the Fence results were useless in principle. This submission was unsupported by evidence. To the contrary, Mr Howe gave unchallenged evidence that the available data does not enable any such conclusion to be drawn."
"The Defendants again contend that I misdirected myself since there was evidence that the migration rate [was] affected [by] the polymer composition. I am perhaps guilty of having expressed myself insufficiently precisely in . It is true that there was evidence that the migration performance of insecticide-incorporating PE nets is affected by the base polymer type used, but the question is whether the addition of LDPE in the quantities used by the Defendants had an important effect. Mr Howe's unchallenged evidence was that the available data did not establish this. Mr Howe also pointed out that it was unclear what polymer blends the Defendants had used when or how they had been developed. This again is a matter I have dealt with elsewhere in the main judgment."
Proceedings in the Court of Appeal
"(i) on the hearing of the Appeal, the Defendants be entitled to rely upon additional evidence, that evidence being the VF polymer specification (WO 2010/015256 A2); and
(ii) should any further disclosure be obtained as a result of (iii) below, the Defendants be at liberty to rely upon those documents if relevant;
(iii) the Claimants be ordered to give further disclosure of any additional documents allied to the specification mentioned above and the research upon which the specification was based or which has taken place after the applications leading to the specification was filed, as more particularly set out in the draft Order attached;
because the specification supports a key element of the Defendants' case which was rejected by the Trial Judge on the basis of lack of evidence."
"the Claimants do disclose to the Defendants Patent Specification No. WO2010/015256 and all documents recording the results of the studies, trials and experiments referred to in the passage from page 11 line 11 to page 12 line 11 of the said specification."
"the Defendants have permission to adduce in evidence and rely upon the report of Professor Gary Stevens for the Court of Appeal dated 12 November 2010 because it has been prepared to assist the Court in understanding the relevance to the appeal of technical documents disclosed by the Claimant [sic] pursuant to the Order of the Court of Appeal made on 8 October 2010."
"2. The Defendants have permission to adduce before the Chancery Division for the purposes of said determination the following evidence:
(i) PCT Application WO 2010/015256.
(ii) Professor Stevens' expert report dated 12 November 2010.
(iii) The four documents numbered 16, 43, 52 and 58 disclosed by the Claimants pursuant to the order of the Court of Appeal dated 8 October 2010.
(iv) The other documents disclosed by the Claimants pursuant to the order of the Court of Appeal dated 8 October 2010 that are referred to in said report of Professor Stevens.
3. The Claimants have permission to adduce before the Chancery Division for the purposes of such determination the following evidence:
(i) An expert report from Mr Gary Howe.
(ii) One or more witness statements containing any factual evidence on which they wish to rely relating to the statements in the documents set out in paragraph 2(iii) above.
7. The hearing of the appeal be adjourned to be re-listed to take place as soon as reasonably practicable after the said determination by Arnold J …"
The effect of the Court of Appeal's order dated 24 November 2010
"(2) The appeal court has power to-
(b) refer any claim or issue for determination by the lower court;
"The additional matter to which Mr Livesey has drawn our attention is CPR r 52.10(2)(b), which gives the appeal court power to refer any claim or issue for determination by the lower court. It seems to me that normally that is likely to arise where the appeal court has taken a view that a particular issue is necessary for decision, but that it could be better for it to be decided at first instance. That may be, of course, on allowing an appeal but it seems to me that the power is defined in sufficiently general terms to allow in a case where it appears to be just and convenient for a point to be referred back for determination by the lower court, even if it is only contingently relevant in the context of an appeal that is still pending. That is exactly this case."
"17. It also seems to me that, at any rate, in circumstances in which the judge has the matter fresh in mind, the hearing having been in the course of March, and has indicated that he would be willing to proceed in this way and in which, as I understand it, it is at least contended that he had before him in the course of the trial, so that it would be reflected in the bundles and in the transcript, all the evidence that would be necessary for him to determine any factual issues, that it would be appropriate and conducive to the overriding objective to allow, and indeed direct, that the judge should address the points that contingently arise in relation to the point on which permission to appeal has now been granted.
18. I should say one or two other things arising consequentially. If the matter does go back to the judge, as I would wish that it should, it will go back on the basis of his indication of willingness to proceed in this way, on the basis of some simple directions with a timetable for written submissions and on the basis that otherwise the rest of the procedure is for him to decide on. He will receive written submissions but he should not receive oral submissions unless he invites them. For my part I do not anticipate that he will need to, or indeed that it will be appropriate for him to, receive additional evidence, but I would not wish to preclude either him or the parties from considering whether additional evidence is necessary on any point.
19. The only other thing I would say in that respect is that, because the appeal is due for hearing in mid-December, it is highly desirable that his judgment should be available in good time before that date, not least because one or other or indeed possibly both parties may wish to take exception with points that he does decide in the course of the supplemental judgment. As I see it, the status of his decision will be that it is, in effect, a supplement to his original judgment so that if there are points in it with which either party is discontented, and on which an appeal can properly be launched, the relevant party can then seek permission to add relevant points to the appellant's notice or the respondent's notice, as the case may be. Of course it may be necessary that further directions are sought from the Court of Appeal in terms of the future conduct of the appeal."
" … This court made it clear that they did not consider it appropriate to try any question of fact as to whether the court had been misled: it is trite law that if a person seeks to show that a judgment has been obtained by fraud, he can proceed by way of an appeal or alternatively by way of a fresh action but that he must proceed in the latter way if there are disputed questions of fact. In this instance, this court proposed a third way to obviate the need for a fresh action to resolve disputed issues of fact. That third way was the remission by this court of an issue to the Chancery Division. CPR 52.10(2)(b) provides that this court can remit any claim or issue for determination by the lower court. After Mr Koshy had obtained permission to appeal, DEG had made an application for permission to file fresh evidence thus demonstrating that there were disputed issues of fact. This court therefore proposed the idea of the remission by this court of an issue to the Chancery Division. This court was not bound to do this, especially if no such relief had been claimed in the notice of appeal, but no doubt felt that it would be appropriate to do so since DEG consented to this course at that stage. But what the court was also entitled to do was to prevent the time of the court being wasted by hearing and determining an appeal on a very limited basis only to be faced at the end of the hearing with an application for the remission of an issue to the Chancery Division. Accordingly, as a matter of case management, this court was entitled to offer the option at that stage. If the offer was refused, the appeal would have to be argued on the basis that Mr Koshy would have to convince this court that this court could grant the relief without hearing fresh evidence that DEG sought to produce."
"I would propose that, for the present, the appeal should be allowed to the extent that the issue of fraud should be referred for trial by a High Court judge. If the judge rejects the allegation of fraud, the original award will stand. If the judge finds that fraud is proved, he should make a reassessment of the damages."
i) In essence, the Court of Appeal's order dated 24 November 2010 required this court to reconsider the conclusion contained in the main judgment at  as refined in the remedies judgment at  ("the Disputed Paragraphs") in the light of new evidence, namely the PCT Application and the Documents, interpreted with the assistance of the expert evidence.
ii) As a matter of necessary implication, the Court of Appeal's order dated 24 November 2010 should be taken to have set aside the issue estoppel that would otherwise arise out of the main judgment and the remedies judgment to the extent necessary to enable that task to be performed.
i) the work reported in the Documents was carried out by VF during the period October 2006 to July 2008, that is to say, approximately 2-4 years after Dr Skovmand devised the initial recipes for Netprotect that were used by the Defendants in their October 2004 trials, and consequently it cannot be suggested that either VF or Dr Skovmand were aware of the work at that time;
ii) as explained below, some of the Defendants' trial formulations and production runs of Netprotect did not include LDPE;
iii) [ADDITIVE A], [ADDITIVE B] and [ADDITIVE C] were included in VF's and the Defendants' formulations not only because of their effect on deltamethrin migration, but also for other reasons, in particular to provide protection against UV light (see the main judgment at , -, -), -, , , , -, , , ,  and ); and
iv) my conclusion that Dr Skovmand used the information in the Fence database as his starting point when devising the initial Netprotect formulations was based upon a variety of considerations, including the fact that I concluded that Dr Skovmand was not a witness of truth (see the main judgment at ), and not solely upon my rejection of the fourth of the seven improbabilities.
Should VF have disclosed the Documents before?
The role of the expert evidence at this hearing
Professor Stevens' evidence
Should an adverse inference be drawn from VF's failure to call factual witnesses?
The PCT Application
"In connection with insecticide control, it is well known that insecticides can be integrated in polymer material in order to prevent insects to work their way through the material. However, when it comes to the control of release rates of insecticides in a polymer matrix, this is regarded as a difficult issue, because a release that is too rapid exhausts the matrix quickly with regard to insecticidal effect, and a too slow release does not have the desired efficiency or suitable regeneration properties in case the insecticide falls off or is removed, for instance, by washing."
Thus the problem identified by the specification is to control the release of insecticide incorporated in a polymer matrix so that it is neither too fast nor too slow.
"Apart from the difficulty of achieving a suitable migration speed of insecticide in polymer matrices, the combination of an insecticide, for example DM (Deltamethrin), and a synergist, for example PBO (piperonyl butoxide), incorporated in a polymer matrix implies additional challenges. Despite the fact that incorporation of a pyrethroid and PBO has been reported in connection with pet collars, for example in International patent application WO 00/40084 or WO 06/127407, the migration speed for long lasting insecticidal nets (LLIN) or fabrics is still an unresolved problem in practice. This is due to the fact that several parameters have to be fitted together to yield a product that is satisfactory. The parameters have to be found such that, firstly, the insecticidal dose on the surface of the material should be sufficiently high for killing insects, secondly, the release should last for more than a year in the case of LLIN, and should allow regeneration of the net's activity in case of washing of the net, and thirdly, the overall content of the insecticide and synergist should be low in order to keep the cost for LLIN at a minimum, as well as to minimize the potential exposure of an end-user to the active ingredients contained in the net. The latter are important factors, because the largest markets for LLIN are regions with low income, and the primary end-users are infants and young children."
"It is the object of the invention to provide an insecticidal polymer matrix containing HDPE and LDPE with optimised migration capabilities for DM, and, especially, a polymer matrix for producing insecticidal fibres for LLIN and other insecticidal fabrics."
"This purpose is achieved with an insecticidal polymer matrix containing HDPE (high density polyethylene) and LDPE (low density polyethylene). The matrix also contains an insecticide as part of the material of the matrix, that is, the insecticide is incorporated into the material. The insecticide is arranged for migration from inside the material to the surface of the matrix. Further, the ratio of the contents of HDPE and LDPE is between 3 and 30, preferably between 5 and 20, rather higher than 5 and lower than 12, such as between 5 and 11 or 5 and 10, or even between 8 and 10. The insecticide is, preferably, an insecticide different from permethrin, and most preferably, the insecticide is deltamethrin (DM)."
"Preferably, the matrix contains PBO (Piperonyl Butoxide) and DM (Deltamethrin) as part of the material of the matrix.
As experiments have shown, the amount of LDPE in a polymer matrix with HDPE should not be too high, in order to assure an optimal migration rate of the PBO and the DM, whilst concomitantly achieving optimal mechanical properties of the polymer matrix. In this case, both substances migrate to the surface of the material, preferably a mosquito net, and expose the insect to PBO and DM instantaneously."
"Experimentally, the ratios between PBO and DM were found advantageous in connection with a polymer matrix consisting of HDPE and LDPE, especially for a polymer matrix, where the ratio between HDPE and LDPE is between 5 and 11 or 5 and 10, such as 8 and 10. However, it seems that this is valid as well for polymer matrices, where other polymers are added to HDPE and LDPE."
"The surface content of PBO and DM on the surface of a polymer matrix depends on the migration rate of PBO and DM in the polymer as well as on the thickness of the polymer substrate (i.e. the distance to the surface). The migration rate is influenced by, amongst other factors, the proportion of amorphous phase in the polymer (i.e. the percentage of crystallinity), the diffusion coefficient, which, in turn, is affected by the temperature and the degree of affinity between the additives and the polymer. Therefore, the surface content of DM and PBO at any moment in time is determined by a combination of various thermodynamic effects but also by the shape of the polymeric substrate being in the form of a yarn, a foil, or a bulk product. The above ratios were verified as being useful for an insecticidal matrix in the form of a fully drawn monofilament yarn with a diameter of between 0.05 mm and 0.3 mm, preferably between 0.1 mm and 0.15 mm. Especially, the HDPE and LDPE ratio of between 5 and 10, or rather between 8 and 10, was suitable for such filaments. However, the above figures are also useful for multifilaments having a linear density in the same range."
"In addition, special migration promotors [sic] or inhibitors may be used to adjust the migration speed. For example, some promotors or inhibitors may work more or less on DM than on PBO, by which the migration speed of these two components can be adjusted relatively."
There is nothing in the specification to indicate what "migration promotors or inhibitors" the inventors have in mind.
"The path leading to the invention did comprise a number of intermediate steps, in as much as the solution, despite its simplicity is not straightforward.
In the teaching in the field of insecticidal nets, it has hitherto been assumed that PBO has to be transferred to the mosquito well in advance to the exposure to DM, because the PBO was believed to need a certain time in the mosquito before it temporarily breaks down the resistance mechanism."
"One of the corner stones of the invention is the fact that experiments revealed that the bioefficacy of PBO and DM treatment is highest when mosquitoes were exposed to PBO and DM simultaneously. As described above, this is against the teaching in the field of insecticidal nets. A proof for this is illustrated in FIG. 1, showing that for different dosages, there was a remarkable increase in efficacy when DM and PBO were provided to the mosquito at the same time.
Having recognised this, there was a new motivation for providing a polymer matrix containing PBO and DM, where both can be found on the surface of the matrix and migrate at a similar rate so as to replenish the surface after depletion (by washing, for instance) in order to expose insects to DM and PBO at the same time. As long as there is a steady release of these two substances, the efficacy against mosquitoes is optimal. Of course, this is compounded by the added constraint for LLINs that the said polymer matrix, once knitted into a netting material, should have suitable migration properties so that PBO and DM be regenerated at the surface of the yarn/fabric following washing."
"The question then arises, which material should be chosen for the matrix. Studies revealed that polyester has a very slow migration rate, which was not sufficient to release enough DM and PBO through migration of polyester yarn of 100 Denier, even when used a multifilament with 35 filaments. HDPE had a release rate which was higher than for polyester, but not high enough for sufficient insecticidal efficacy or regeneration at a rate suitable for mosquito netting materials, despite good mechanical properties making it suitable for knitting into netting material. On the other hand, LDPE has a migration rate, which is far too high for a LLIN, and yarns made of pure LDPE have low mechanical properties that make them unsuitable for knitting into netting material. Thus, according to the invention, a mixture of LDPE and HDPE was envisaged, and it was found empirically, that for sufficient but also long lasting release of DM and PBO, a mixture of HDPE and LDPE was optimum, where the weight ratio between HDPE and LDPE was between 30 and 3 and rather between 20 and 5. The ratio depends on the thickness of the matrix. For monofilament yarns with a thickness of 0.06 mm, the HDPE/LDPE weight ratio was best between 15 and 25 and for yarns with a thickness of 0.25 mm, the ratio was best between 4 and 7. For yarn thickness in between these two numbers, the ratio may be interpolated. These parameters seem to give the said monofilament yarns adequate crystallinity at a given draw ratio and therefore an appropriate migration rate at the typical temperature these products are used.
In the experiments, no other polymers were introduced into the matrix. The above ratios corresponded in these experiments to a LDPE weight content of between 3.5% and 35% in the HDPE/LDPE matrix, whereas, however, the preferred content of LDPE in terms of weight was between 5% and 17%, better between 8% and 12%.
A successful monofilament yarn with a diameter of 0.10 mm to 0.15 mm, for example around 0.12 mm, the content of HDPE and LDPE in terms of weight was at a ratio between 8 and 10, rather around 9, corresponding to an LDPE content of around 10%, when no other polymers were introduced.
However, as it turned out, not only the ratio between the content of HDPE and LDPE could be used to optimise the yarn with respect to long lasting high efficiency. Also the content of the PBO content relative to the DM content proves to be crucial."
"Examples of successful yarns had diameters of between 0.10 mm and 0.15 mm, for example around 0.12 mm, containing 4g DM per kg polymer and 25g PBO per kg polymer. For example, the content of HDPE and LDPE in terms of weight at a ratio is between 8 and 10, for example around 9. Due to necessary initial migration before a sufficient content is reached at the surface of the matrix, the yarn, advantageously, can be stored for a certain time to reach sufficient efficacy, for example a week to reach 80% efficacy."
"The monofilament polyethylene yarns may successfully be used for bed nets, where the entire net is provided with such material. However, in case that the side walls of the nets are preferred to be produced in polyester multifilament due to the relatively higher softness and cotton like feeling, the extruded HDPE/LDPE monofilament yarn may be used for the top part of the net. The efficacy will in most cases still be high, because mosquitoes typically attack their potential victims from above and tend to land on the roof of bed nets, especially rectangular bed nets.
As a further addition, migration promoters may be included in the molten matrix prior to extrusion of the insecticidal polyethylene blend."
Again, there is nothing in the specification to indicate what "migration promoters" the inventors had in mind.
"An insecticidal polymer matrix made of a material containing high density polyethylene (HDPE) and low density polyethylene (LDPE), and deltamethrin (DM), wherein the DM is part of the material and arranged for migration from inside the material to the surface of the matrix, wherein the ratio of the content of HDPE to LDPE is between 5 and 20 in terms of weight."
i) Retention index. This is a measure of the loss of active ingredient following an exposure condition (typically a wash cycle). It is commonly expressed as percentage after n washes (where n is often 1), such that retention index = (active ingredient after n washes/active ingredient after zero washes) x 100.
ii) Release index. This is a measure of the change in surface concentration of an active ingredient. In this test the surface concentration is first determined (surface extractable 1 or SE1), then the surface is cleaned and the sample allowed to regenerate and the surface concentration determined again (SE2) and then that process is repeated (SE3). The release index is the ratio SE2/SE3.
iii) Bioassay tests. These test the effectiveness of a formulation in terms of its main function of killing mosquitoes as a function of storage time and/or temperature. The insecticidal effect depends on the surface concentration of deltamethrin. Good bio-efficacy requires a moderate rate of migration of deltamethrin to the surface of the yarn or fabric: too high a migration rate leads to rapid depletion of deltamethrin, while too low a migration rate results in poor surface regeneration of deltamethrin after it has been lost due to evaporation and/or washing.
iv) Storage stability tests. VF was interested in two aspects of storage stability at elevated temperatures. The first concerned loss of active ingredients due to evaporation from the surface. The second concerned isomerisation of deltamethrin to the inactive R-isomer (see the main judgment at ). The latter aspect is not relevant to the issues presently before me.
Z617 trial (October-November 2006)
R3 trial (December 2006-January 2007)
"PBO was successfully incorporated by the new extrusion method into the PE yarn. We were able to get a product after production with 100% FM towards Culex, EVEN with DM level of 1/10 of the normal used concentration.
This means we have a product that works 100% against Culex, with a very low DM level under the condition that is not washed.
After 3 washes the mortality against Culex drops significant and after 5 W mortality drops to 32% even against susceptible mosquitoes. I.e. the migration of PBO and DM is too fast.
Main issue is to slow down migration rate. This can be done by lowering the migration enhancer and introduce, if needed, a migration inhibitor. Two chemistries are identified to do this and a new test matrix has been agreed upon. Deadlines put very tight."
"The migration rate of DM and PBO in PE may be different. We assume PBO migrates faster than DM.
[ADDITIVE A]: Acts as a migration enhancer
[ADDITIVE C]: Act as a migration inhibitor".
R4 and R7 trials (February-March 2007)
"A too slow migration HDPE drops in bio-efficacy shortly, even still containing more than [REDACTED]% of DM, too fast migration PES coating empties the storehouse very soon at 20W, with about [REDACTED]% DM left. A moderate migration in PE incorporated (Netprotect) is bio-effective upto 35W with [REDACTED]% of DM in storehouse."
- Migration in LDPE is too fast, consequently, LDPE composition in mixture with HDPE is expected to be the KEY factor in driving migration.
PES incorporated is also a deadlock of DM and PBO in terms of migration. By any mean-time storage or heat up, we could not get PES incorporated sample to be bio-active. …
D. HDPE incorporated
14 different formulations were made by Gopi/VKA in Mar. 07. These formulation is monofilament, d=[REDACTED] mm, prepared in different colors in groups.
Data on these different 14 different formulations renders the following observations:
1. Slow migration of both DM and PBO in 100% HDPE netting. This fact is going to be fixed by controlling LDPE percentage.
5. UV stabilisers, [ADDITIVE A] and [ADDITIVE C] show positive role in UV protection of DM, while no clear interaction/protection with VF30. [ADDITIVE B] presents in all samples, therefore the role of [ADDITIVE B] remains are unknown. The fact that samples were in different colors makes any conclusion on UV protections quite shaky.
6. UV stabilisers, [ADDITIVE A] in theory is migration accelerator under [this sentence appears to be unfinished]".
"Outcome of recent study on PE PermaNet 3.0, especially from co-incident LDPE sample made at Aachen: by controlling LDPE/HDPE ratio we can control/speed up the migration of DM and VF30 in PermaNet 3.0.
Please come up with a matrix for PermaNet 3.0 based on the direction of LDPE/HDPE mixture."
This is evidently a deduction from the existing data combined with a proposal to test that deduction.
"15 recipes S1-S15 was set up based on the picture of R3 – where VF30 was assumed to play bleeding effect in PE. We learn after receiving samples from you (S1-S3) that smt wrong with this hypothesis and only by then we knew that R3 is LDPE.
Not VF30 or any other additatives [sic], but LDPE plays key role in migration. It turns the trial to new direction.
S1-S15, based on pure HDPE, we are trying to grasp as much as possible information out of this. Most focusing on
(1) additatives' role in driving migration
(2) UV protection
Pls. do not worry, your work on S1-S15 is not a waste at all. Testing is still running. But most likely none of them is qualified for PermaNet 3.0 due to generally slow migration. We do not know yet at the moment.
If you face time and stock issue, pls. consider go ahead first with PE5 to PE9. This group tackles the right percentage of LDPE I the mixture. And if we can optimise the LDPE percentage, we can play better with two other groups, PE1-PE4 and, PE10-PE13.
Keyword for this phase is: LDPE percentage:-))).
For [REDACTED]% LDPE, if we can stretch to that far, it is good to have one more point in the curve. 100% LDPE gives RI = [REDACTED]% , 100% HDPE RI = [REDACTED]%."
"PE incorporation – LDPE
Migration in LDPE is too fast
1. High RI under washing
2. Higher LDPE, faster loss to air
LDPE percentage is considered as key driving factor in controlling migration in PE bednet."
R12 trial (May 2007)
"A. PE1 with [REDACTED]% LDPE is quite comparable with Netprotect in terms of chemical assay.
(1) RI/DM of PE1 = [REDACTED]%.
(2) Surface content development
PE 1 behaves quite poor in bioassay with aedes, with far from saturated surface at the beginning. This fact requires verification.
B. PE5 and PE7, the only difference is [REDACTED]% and [REDACTED]% LDPE respectively. Higher LDPE, faster surface development.
(1) Lower RI of both VF30 and [ADDITIVE A] observed in PE7 and higher surface content development along SE1, SE2, SE3 in chemical assay
(2) PE7 has higher bio-efficacy at 0W, thanks to [REDACTED]% LDPE. After 1W, faster migration in PE 7 does not compensate for the higher loss during washing, therefore bio-efficacy at 1W is poorer compared to PE5
This point, as Huyen commented in another separate e-mail, [REDACTED]% LDPE might be an extreme for migration.
Let see the balance between migration-loss to wash slide versus number of wash.
C. Compare PE5, PE7 with a group of R7 sample with LDPE = 0%, higher LDPE, higher surface content development relatively.
A,B,C: confirm LDPE drives migration significantly and dominantly.
E. Bio-efficacy with culex at 0W and 1W was made with abundant DM source provided by PN 2.0. Data would be compromised if tested with limited DM source as seen in PE1
>>>Even with high VF30 ([REDACTED] g/kg) and 10% LDPE, bio-efficacy against culex is still an issue to pass 80% FM. Defining a proper goal/text for bio-efficacy against culex is an important task. So far, we can reach 100% FM on Culex only on LDPE 100% sample and few coating samples.
"1. Higher VF 30 and/or higher LDPE, faster migration seen by chemical assay
PE7 against PE5: [REDACTED]% LDPE is faster migration than [REDACTED]% LDPE
PE8 against PE5: Higher VF30, faster migration".
"Too few data to make a conclusion, especially with famously high method uncertainty as bioassay. Statistically, no difference in bio-efficacy between three formulations."
R15 trial (June 2007)
"An HDPE/LDPE ratio of [REDACTED] gives a [REDACTED] mm diameter yarn with good migration properties, albeit perhaps a tad slow. A ratio of [REDACTED] is difficult to extrude. It is possible that the optimal ratio be slightly underneath [REDACTED], i.e. perhaps [REDACTED]."
- "The migration speed of PBO and DM in a monofilament polyethylene yarn is very sensitive to the type of polyethylene. In HDPE, DM and PBO do not migrate. In LDPE, they migrate too fast. An HDPE/LDPE ratio of [REDACTED]seems like a good compromise between the issue of migration speed and that of physical integrity of the yarn. Some subsequent trials could include a ratio of [REDACTED], but probably not further.
- The yarn diameter seems to have a great impact on the migration speed of DM and PBO, with [REDACTED] mm yarn demonstrating better migration than [REDACTED] mm. Despite of the largest reservoir in the latter case, it is possible that the bulk of the polymer matrix to be crossed by the migrating ingredients be too important."
R16 trial (June 2007)
R25 trial, Phase I (October 2007)
4. Recommendation for the next scale up production
(i) Remove LDPE completely in order to slow down the migration
R25 trial, Phase II (May 2008)
"Explore the impact of [REDACTED] on the storage stability of DM-PBO combi yarns, with and without [REDACTED]. Explore the impact of varying the LDPE contents on one known recipe."
It appears from this Document that another goal was to try out a certain producer.
R25 trial, Phase III (July 2008)
"Confirm the impact of [REDACTED], especially at high levels of [REDACTED], on the storage stability of DM-PBO combi yarns. Explore the potential of using [REDACTED] as a [REDACTED], for DM-friendly light stablization. Explore the impact of varying the LDPE contents on one known recipe, at two different levels of [REDACTED]. Compare fabrics made of different yarns in the same color, in terms of stability to Neon light."
Question (i): how strongly the migration rate of deltamethrin is affected by the addition of LDPE to the polymer mix
i) Samples PE1 ([REDACTED]% LDPE and deltamethrin) and PE5 ([REDACTED]% LDPE and PBO) do not have significantly different retention indices than the corresponding 100% HDPE R4/R7 samples.
ii) By contrast, PE7 ([REDACTED]% LDPE and PBO) does have a significantly different retention index to PE5 ([REDACTED]% LDPE and PBO).
iii) PE7 and PE8 behave very similarly, although PE7 has 30% LDPE and PE8 has 10% LDPE, apparently because the difference in LDPE content is counteracted by the fact that PE8 has roughly double the PBO concentration to PE7.
i) Professor Stevens' analysis was based on five samples: R64 and R93 (0% LDPE), AY7 ([REDACTED]% LDPE), AY2 ([REDACTED]% LDPE) and AY8 ([REDACTED]% LDPE). But AY8 must be treated with caution, because the recovery data for this sample were abnormally low for no apparent reason. Worse, R64 and R93 are not comparable with AY7, AY2 and AY8, since R64 and R93 were reference samples containing no [REDACTED] whereas AY7, AY2 and AY8 did include [REDACTED].
ii) Figure 11 contained the wrong data, since Dr Herman had plotted [ADDITIVE B] retention data rather than PBO retention data.
iii) If one compares the AY7 data ([REDACTED]% LDPE) with the AY2 data ([REDACTED]% LDPE), there is no appreciable change in the retention of deltramethrin.
Question (ii): how that effect (if any) compares to the effect of [[ADDITIVE A], [ADDITIVE B] and [ADDITIVE C]]
i) [ADDITIVE A] acts, and was known to Dr Skovmand to act, as a migration enhancer: see , , -, -, , , , ,  ;
ii) [ADDITIVE C] acts, and was known to Dr Skovmand to act, as a migration inhibitor: see , , , ;
iii) The effect of [ADDITIVE A] can be seen even in a polymer matrix containing [REDACTED]% LDPE, which is one reason why Dr Skovmand reinstated it after experimenting with its removal from the Fence 65.F.0503.5 recipe (which contained [REDACTED]% LDPE) as Ciba had recommended, the other being its UV protective effect: see , , , . Apart from that, the relative effect of LDPE on the one hand and [ADDITIVE A]/[ADDITIVE B]/[ADDITIVE C] on the other hand on deltamethrin migration is unknown.
Question (iii): whether the outcome of issues (i) and (ii) above renders the Fence results not useful for the formulation of the Defendants' product
i) In general terms, the addition of LDPE to a polymer matrix otherwise consisting of pure HDPE would be expected to increase the migration rate of deltamethrin, with higher percentages of LDPE having a greater effect than lower percentages; but there is no evidence that the addition of LDPE in the quantities used by the Defendants (i.e. [REDACTED]% where present) has a significant effect on migration rate.
ii) [ADDITIVE A] acts, and was known to Dr Skovmand to act, as a migration enhancer. [ADDITIVE C] acts, and was known to Dr Skovmand to act, as a migration inhibitor. The effect of [ADDITIVE A] can be seen even in a polymer matrix containing [REDACTED]% LDPE. Apart from that, the relative effect of LDPE on the one hand and [ADDITIVE A]/[ADDITIVE B]/[ADDITIVE C] on the other hand on deltamethrin migration is unknown.