Wednesday 23 November 2011

T 1508/08 – Correctional Facilities


As we have seen in an earlier post, drafters of applications dealing with monomers and polymers have to be careful because it is easy to mix up these terms … and difficult to correct the resulting errors.

The present appeal was filed after the Opposition Division (OD) had revoked the opposed patent. The decision in itself is not very surprising but it reminds us of the rules that govern corrections.

Claims 1, 7 and 9 of the patent as filed read (in English translation):
1. A process for the production of conducting wires coated with cross-linked polyethylene, in which process a granulate made of polyethylene is coated with a fluid cross-linking agent, the coated granulate is melted in an extruder and extruded onto the electrical conducting wire, and the extruded layer is cross-linked by heating to a temperature above the decomposition temperature of the cross-linking agent, characterized in that a mixture of granulate, meal, or powder made of a polyethylene homopolymer and a polyethylene copolymer is coated together with the cross-linking agent and stabilizer, wherein the portion of copolymer in the coating on the cable is between 1 and 8% by weight.

7. A process according to claim 1 to 6, characterized in that a polyethylene copolymer having a portion of copolymer of over 16% is used.

9. A process according to any one of claims 1 to 8, characterized in that ethylene vinyl acetate (EVA), ethylene butyl acrylate (EBA), ethylene ethyl acrylate (EEA), and/or ethylene methyl acrylate (EMA), with a portion of copolymer being from 10 to 30% by weight, is used as polyethylene copolymer. (my emphasis)
Claim 1 of the main request before the Board read (in English translation):
1. A process for the production of a cable consisting in conducting wire coated with cross-linked polyethylene, in which process a granulate made of polyethylene is coated with a fluid cross-linking agent, the coated granulate is melted in an extruder and extruded onto the electrical conducting wire, and the extruded layer is cross-linked by heating to a temperature above the decomposition temperature of the cross-linking agent, characterized in that a granulate, meal, or powder made of a polyethylene homopolymer and a polyethylene copolymer is mixed together in a tumbler mixer at an elevated temperature, which temperature is below the melting point of the polyethylene homopolymer and/or polyethylene copolymer and is simultaneously coated with a fluid mixture of cross-linking agent and stabilizer, wherein the polyethylene copolymer is chosen from among ethylene vinyl acetate (EVA), ethylene butyl acrylate (EBA), ethylene ethyl acrylate (EEA), and/or ethylene methyl acrylate (EMA), with a portion of comonomer from 10 to 30% by weight, and wherein the portion of comonomer in the coating on the cable is between 1 and 8% by weight. (my emphasis)
*** Translation of the German original ***

[3.1] The parties did not agree on whether the comonomer portion mentioned in claims 1 to 4 and 7 of the main request complied with the requirements of A 123(2).

The passages of claims 1 to 4 and 7 of the main request read (emphasis by the Board):
  • “wherein the portion of comonomer in the coating on the cable is between 1 and 8% by weight” (claims 1 to 4)
  • “wherein the polyethylene copolymer is chosen from among ethylene vinyl acetate (EVA), ethylene butyl acrylate (EBA), ethylene ethyl acrylate (EEA), and/or ethylene methyl acrylate (EMA), with a portion of comonomer from 10 to 30% by weight” (claims 1 to 4)
  • “a polyethylene copolymer having a portion of comonomer of above 16% by weight” (claim 7).
[3.2] These passages are derived from the following passages of original claims 1, 7 and 9 (emphasis by the Board):
  • “wherein the portion of copolymer in the coating on the cable is between 1 and 8% by weight” (original claim 1)
  • “wherein ethylene vinyl acetate (EVA), ethylene butyl acrylate (EBA), ethylene ethyl acrylate (EEA), and/or ethylene methyl acrylate (EMA), with a portion of copolymer from 10 to 30% by weight are used as polyethylene copolymer” (original claim 9)
  • “a polyethylene copolymer having a portion of copolymer of above 16% by weight” (original claim 7).
The passages of the original claims 1, 7, and 9 do not disclose a portion of comonomer but exclusively refer to a portion of copolymer (see emphasis by the Board).

Also, the rest of the application as originally filed exclusively refers to portions of copolymers, wherein the following is disclosed:
  • “The essential advantage of the invention can be seen in that by the use of a mixture of polyethylene homopolymer and polyethylene copolymer with a limited amount of copolymer, the resistance of the cable insulation to the formation of water trees can be significantly increased.” (last paragraph of page 2)
  • Coating of a wire with a mixture of 20 parts of polyethylene copolymer, 80 parts of LDPE (polyethylene homopolymer), 2 parts of dicumyl peroxide and 0.2 parts of stabilizer, corresponding to a portion of polyethylene copolymer of 19.6%, based on the mix used for coating (Examples 1 and 2).
  • Coating of a wire with a mixture of 20 parts of polyethylene copolymer, 80 parts of LDPE (polyethylene homopolymer) and an undefined quantity of highly concentrated peroxide/stabilizer batch based on polymers (Example 3).
The application as originally filed, therefore, does not directly disclose the comonomer portions claimed in claims 1 to 4 and 7 of the main request.

[3.3] According to the [patent proprietor], the comonomer portions of claims 1 to 4 and 7 are obtained when the expression “portion of copolymer” in claims 1, 7, and 9 as originally filed is corrected to read “portion of comonomer”. This correction was allowable pursuant to R 139.

As mentioned in G 3/89 [2] the requirements for allowing a correction consist in that
(a) the incorrect information is objectively recognisable as such for the skilled person, and
(b) the correction that is carried out must correspond to the only possible correction which the skilled person would consider on the basis of the original disclosure of the opposed patent and his common general knowledge.

[3.4] As far as the first requirement is concerned, the Board agrees with the [patent proprietor] that the indications regarding the copolymer portions are contradictory in the application as filed. For instance, there is a contradiction between the portion of copolymer between 1 and 8% by weight in the coating according to original claim 1 and the portion of polyethylene copolymer of 19.6%, based on the mix used for coating in Examples 1 and 2. Moreover, there is a discrepancy between the portion of copolymer between 1 and 8% by weight in the coating mentioned in original claim 1 and the portions of copolymer above 16% from 10 to 30% by weight disclosed in claims 7 and 9. Finally, claims 7 and 9 of the application as originally filed are contradictory to each other because claim 7 requires a portion of copolymer of above 16% by weight whereas claim 9, which is dependent on claim 7, also appears to allow portions of copolymer that are below 16%.

Also, the wording of claims 7 and 9 of the application as originally filed “polyethylene copolymer having a portion of copolymer …” is objectively incorrect because a copolymer does not contain a portion of copolymer.

Therefore, the Board agrees with the [patent proprietor] that based on the whole disclosure of the originally filed application, it is obvious for the skilled person that the portions of copolymer mentioned in original claims 1, 7 and 9 are defective. Thus the first requirement for allowing a correction pursuant to A 139, as expressed in G 3/89, is fulfilled.

[3.5] On closer inspection, in order for the second requirement (b) mentioned in G 3/89 to be fulfilled, two things are required, i.e. that the skilled person, on the basis of the original disclosure of the opposed patent and taking into account his common general knowledge,
  • would consider the correction that has been carried out, and, if so,
  • would consider it to be the sole conceivable (in Frage kommend) correction.
[3.5.1] The Board will first examine whether the skilled person would consider the correction of the expression “portion of copolymer” to “portion of comonomer” […].

According to the [patent proprietor] it is clear for the skilled person that the desired effect of increasing the resistance to the formation of water trees [mentioned] on the last paragraph of page 2 of the originally filed application, can be obtained by limiting the portion of comonomer but not by limiting the portion of copolymer, as stated in this paragraph.

If this view was to be adopted, then one would expect the relevant portion of comonomer that is needed to obtain the desired effect to be given in the examples of the application – in the form of the erroneously used expression “portion of copolymer”. However, this is not the case. Quite to the contrary, the examples only contain indications regarding the content of copolymer (“20 parts of polyethylene copolymer” in Example 1 and “20 parts of PE copolymer” in Example 3) but do not make any statement of the comonomer contained therein, let alone its portion.

Thus, based on the original disclosure, and contrary to the arguments of the [patent proprietor], one has to assume that it is the portion of copolymer, and precisely not the portion of comonomer, that is relevant for obtaining the effect the application aims at. For this reason alone the skilled persons would not take into account the correction carried out by the [patent proprietor].

Moreover, this correction […] does not resolve the lack of clarity regarding the portions of copolymer in the application as originally filed in a technically meaningful way, as claimed by the [patent proprietor] […]. The correction of claim 7 leads to a portion of comonomer of above 16%, whereas corrected claim 9, which depends on claim 7, allows for portions of comonomer below 16%. Moreover, it is not clear whether the comonomers contained in LLDPE and VLLDPE are deemed to contribute to the portion of comonomers or if they may not be taken into account, because, according to original claim 8, LLDPE and VLLDPE are homopolymers, i.e. free from comonomers. Finally, it is not clear whether the polyethylene copolymers used in the examples have a portion of comonomer according to the claim and whether, therefore, the examples are consistent with the claims as corrected. Therefore, in this context, the Board cannot share the opinion of the [patent proprietor] according to which the portion of comonomer of the polyethylene copolymer in the examples is between 10 and 30% by weight, as indicated in original claim 9, because original claim 9 is a dependent claim and the portion of copolymer mentioned therein is not to be considered as an essential feature, i.e. a feature that is necessarily present in the examples.

Therefore, notwithstanding the correction, not only are there unresolved unclear issues, but there are even new ones added. For this reason also the skilled person would not consider the correction that has been made by the [patent proprietor].

[3.5.2] But even if one assumes, in favour of the [patent proprietor] that the skilled person would have considered the correction made by the [patent proprietor], this correction would not be the only possible correction.

For instance, the skilled person could keep the portion of copolymer of between 1 and 8% by weight mentioned in claim 1 and only correct the portions of copolymer mentioned in claims 7 and 9. Such a correction would indeed resolve the lack of compatibility between the portion of copolymer in claim 1 on the one hand and the one of claims 7 and 9 on the other hand and eliminate the objectively incorrect wording “polyethylene copolymer having a portion of copolymer …” in those claims.

As an alternative, the skilled person could keep all the portions of copolymer in the application and only insert the expression “…, based on the polymer mix” after the indication of the portions of copolymers. This would at least eliminate the objective incorrectness in claims 7 and 9 because then the portion of copolymer mentioned in those claims is not a portion of copolymer of the copolymer but of the polymer mix. Moreover, this would eliminate the contradiction between original claims 7 and 9 on the one hand and the examples on the other hand because then the portions of copolymer of the examples would then be encompassed by the ranges required in claims 7 and 9. Finally, the claims amended accordingly would be consistent with the last paragraph of page 2 of the description, which deals with the essential character of the portion of copolymer.

[3.5.3] Summing up, it can be said that the correction carried out by the [patent proprietor] would not be considered by the skilled person for the original claims 1, 7, and 9 and, if at all, would only be one of at least three conceivable corrections.

Thus the second requirement (b) for allowing a correction pursuant to R 139 is not fulfilled.

[3.6] The amendment of the expression “portion of copolymer” to “portion of comonomer” in the claims of the main request is not based on a correction that can be allowed pursuant to R 139. Therefore, this correction violates the requirements of A 123(2).

During the oral proceedings before the Board, the patent proprietor also filed auxiliary requests wherein the correction was retracted. The Board considered these requests, which had been withdrawn beforehand, to be new requests and refused to admit them into the proceedings:

[4.3.4] Summing up, it can be said that the [patent proprietor], by filing the new auxiliary requests, not only contradicts all his prior submissions, but also revives objections which had long been overcome by the preceding requests, at the latest possible moment of the appeal proceedings. The Board is of the opinion that this way of proceeding comes very close to an abuse of proceedings and, irrespective of that, in any case, does not comply with the requirement of procedural economy.

The appeal was dismissed.

To download the whole decision (in German), click here.

The file wrapper can be found here.

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