T 0353/06 16-07-2008

Summary of Facts and Submissions

I. The appeal is against the decision of the Opposition Division posted 20 January 2006 revoking European patent No. 0 805 009 on the grounds that the subject-matter of independent claim 1 of the main request of the appellants (patent proprietors), ie claim 1 as granted, was not new, Article 54 EPC, with respect to the alleged prior use "Hüls AG" and that the subject-matter of the corresponding claim of the auxiliary request did not involve an inventive step, Article 56 EPC.

II. Oral proceedings were held before the Board of Appeal on 16 July 2008.

III. The appellants requested that the decision under appeal be set aside and the patent be maintained as granted (main request), or on the basis of claims 1 and 2 filed as "auxiliary request" on 30 May 2006 (hereinafter this request is denoted as first auxiliary request), or on the basis of either the second or third auxiliary request filed on 16 June 2008. If the Board should decide the subject-matter of the patent to be novel, the appellants requested that the case be remitted to the first instance for further prosecution.

The respondent (opponent) requested that the appeal be dismissed.

IV. The following documents were inter alia referred to in the appeal proceedings:

E2 Offer of Werner & Pfleiderer GmbH to Hüls AG dated 10 March 1993 concerning "Modification parts and accessory aggregates for your ZSK 120 / UG 200 A for manufacturing polypropylene mini granules"

E3 Order No. 31 985 290 of Hüls AG to Werner & Pfleiderer GmbH dated 30 March 1993

E4 Order confirmation No. 545060 - 002 and 545060 - 003 of Werner & Pfleiderer GmbH to Hüls AG dated 25 June 1993

E8 Reisebericht (Service Report) of Mr Winkler dated 23/12/93 including "Maschinendatenblatt ZSK 120/UG200A, Hüls AG / Marl 1993"

E12 Plastics Extrusion Technology, Edited by Hensen, F. et al., Carl Hanser Verlag, München 1988, pages 430 to 433 (filed as "Anlage E13").

E14 Unterwassergranulierung - Bauart Werner & Pfleiderer, Pfaff, G., in "Granulieren von thermoplastischen Kunststoffen", VDI-Verlag GmbH, Düsseldorf, 1974, pages 171 to 181.

E16 Lexikon Werkstofftechnik, edited by Gräfen, H., VDI-Verlag GmbH, Düsseldorf, 1993, pages 779 to 785.

V. Claims 1 to 3 of the main request (ie of the patent as granted) read as follows:

"1. A method for producing polyolefin resin granules which comprises the steps of:

extruding by using a kneading extruder a polyolefin resin from a die nozzle into water, and

cutting the extrudate with a cutter blade in the water,

characterized in that

the kneading extruder is a homodirectional twin-screw kneading extruder,

the die nozzle has a die nozzle hole having a diameter of less than 2 mm and a discharge amount per die nozzle hole of 2 - 8 Kg/hr,

the water has a temperature of 5 - 90 ºC which is lower than the temperature of the resin by 140 - 220 ºC, and

the peripheral speed of the cutter blade is 13 - 27 m/sec."

"2. A method as claimed in Claim 1, wherein the polyolefin resin contains talc as a nucleating agent."

"3. A method for producing polyolefin pre-foamed beads, which comprises pre-foaming the resin granules obtained in Claim 1 or 2."

Claim 1 of the first auxiliary request differs from claim 1 of the main request in that the feature "wherein the polyolefin resin contains talc as a nucleating agent" is added at the end of the claim, ie said claim corresponds to claim 2 as granted.

Claim 1 of the second auxiliary request differs from claim 1 of the main request in that the expression "A method for producing polyolefin resin granules which comprises" is replaced by the expression "A method for producing polyolefin pre-foamed beads, which comprises pre-foaming the resin granules obtained by the process comprising", ie said claim corresponds to the alternative of claim 3 as granted which refers to "obtained in Claim 1 [deleted: or 2 ]".

Claim 1 of the third auxiliary request differs from claim 1 of the second auxiliary request in that the feature "wherein the polyolefin resin contains talc as a nucleating agent" is added at the end of the claim, ie said claim corresponds to the alternative of claim 3 as granted which refers to "obtained in Claim [deleted: 1 or ]2".

VI. The relevant arguments of appellants, in writing and during the oral proceedings, were as follows:

Admissibility of the opposition

The Opposition Division held the opposition to be admissible on the ground that the respondent had indicated in its notice of opposition the date on which the alleged prior use occurred, what had been used and all the circumstances relating to the use, "ie that Werner & Pfleiderer had sold and delivered machine parts to Hüls AG for the modification of an extruder ZSK 120, and had done the modification and the start-up of the modified machine" (see Reasons 1.2, last paragraph, of the decision under appeal). However, claim 1 of the patent in suit was directed to a method, not to an apparatus. Werner & Pfleiderer had delivered hardware, not a method to produce granules using that hardware. A crucial piece of information was therefore missing in the notice of opposition, namely who had provided the process parameters used during the start-up test runs as indicated in document E8: Werner & Pfleiderer, or Hüls AG. Without this information, the alleged prior use was not sufficiently substantiated. The opposition was therefore to be rejected as inadmissible, cf. Rule 55(c) EPC 1973.

Prior use "Hüls AG"

Hüls AG had taken the initiative in 1993 to contact Werner & Pfleiderer with a view to produce mini PP granules on its existing extruder of the type ZSK 120 which had to be modified for that purpose. Hüls AG had merely sub-contracted out the manufacture of machine parts, designed to their own specifications, to Werner & Pfleiderer. At best Hüls AG and Werner & Pfleiderer had to be considered as two companies jointly developing a new apparatus. According to the case law of the boards of appeal of the EPO an implicit secrecy obligation had to be assumed in such cases (sub-contractor or joint development). As regards the modified machine, Hüls AG was therefore not a member of the public.

The start-up test runs on the modified machine took place at the premises of Hüls AG. The polypropylene resin, which determined the process parameters for manufacturing granules from said resin, and the throughput were provided by Hüls AG. In other words, the method for producing polypropylene resin granules used during the start-up test runs was provided by Hüls AG. Since Werner & Pfleiderer did not "own" the inventive method to perform the test runs - Hüls AG did -, there was no "making available" of the method to Hüls AG, and there was no "public". The alleged prior use "Hüls AG" was therefore not proved as far as it concerned the method.

Objection of lack of novelty

The objection of lack of novelty was raised only with respect to the alleged prior use "Hüls AG". Since the alleged prior use of the method was not proved, the subject-matter of claim 1 of the main request was novel.

Objection of lack of inventive step, a fresh ground for opposition?

The opposition had been solely based on an alleged prior use, and only the single legal ground for opposition "lack of novelty" had been substantiated in the notice of opposition. The objection of lack of inventive step was thus a fresh ground for opposition. No permission was given to the Board to examine this ground. The present case had to be distinguished from the case whereby an opposition was solely based on lack of novelty with respect to a prior document. In the latter case the opponent could switch to lack of inventive step with respect to the same prior document if the subject-matter of a claim was found to be novel after all, see T 131/01 (OJ EPO 2003, 115). In the former case, if the alleged prior use was not proved, the opponent should not be allowed to switch to lack of inventive step with respect to the same unproved prior use.

Remittal to the first instance?

The objection of lack of inventive step against claim 1 of the main request was never examined by the Opposition Division. A new objection under Article 100(a) EPC (lack of inventive step, Article 56 EPC) against said claim based on document E14 was raised by the respondent for the first time during the appeal proceedings. The case should be remitted to the first instance in order to allow the appellants to have their case decided at two instances.

Added subject-matter, a fresh ground for opposition?

All claims of the first to third auxiliary requests had exact counterparts in claims as granted. The "amendments" with respect to the claims as granted, which merely consisted in deleting certain claims from the set of claims as granted, were no substantive amendments in the sense of Article 123(2) EPC. The ground for opposition under Article 100(c) EPC had not been raised during the opposition proceedings against the granted claims. No consent was given to the Board to examine this fresh ground for opposition.

Objection of lack of inventive step

Main request (independent claims 1 and 3 as granted) and second auxiliary request (claim 3 as granted)

The problem the invention sought to solve was to provide a method for producing mini polyolefin resin granules (cf. claim 1) having a high homogeneity of the dispersed compounding agents and having a desired shape, and a method for producing polyolefin pre-foamed beads (cf. claim 3) having a desired shape and an uniform cell density. Claim 1 of the main request listed four essential parameters each of which were necessary to obtain mini granules having the required properties, namely (i) a discharge amount per die nozzle hole of 2 - 8 Kg/hr, (ii) a water temperature of 5 - 90 ºC, (iii) said water temperature being lower than the temperature of the resin by 140 - 220ºC, and (iv) a peripheral speed of the cutter blade of 13 - 27 m/sec. The comparative Examples listed in Tables 1 and 2 of the patent in suit showed that small deviations of only one parameter outside its claimed range resulted in a failure to produce granules (eg clogging of nozzle) or in defective granules or pre-foamed beads. Document E14 was silent about the use of a homodirectional twin-screw kneading extruder and did not relate to a method for producing mini polyolefin resin granules, ie using die nozzle holes having a diameter of less than 2 mm. This document was also silent about the relative temperature of the water with respect to the resin temperature. The method claimed in claims 1 or 3 as granted was neither disclosed nor rendered obvious by the prior use machine "Hüls AG" and/or prior art documents.

First and third auxiliary requests

The use of a polyolefin resin containing talc as a nucleating agent with the method of claim 1 or 3 as granted was neither disclosed nor rendered obvious by the prior art. The combination of features according to the first auxiliary request was particularly advantageous due to the effects discussed, eg in paragraphs [0012] to [0014] as well as [0020] of the patent in suit. The experiments performed by the appellants submitted on 30 May 2006 showed that foaming pre-foamed beads containing a small amount of talc produced more uniform cells when a homodirectional twin-screw kneading extruder was used for producing said pre-foamed beads, than when a single-screw extruder was used. Moreover, the average cell diameter was particularly large when talc was used, as compared to other kinds of nucleating agents. Document E12 related to the extrusion of foamed intermediate products with single-screw extruders. Talc was only disclosed in this document as a nucleating agent for use in single-screw extruders, not for twin screw extruders, and it was not obvious to the person skilled in the art to select a particular nucleating agent out of several possibilities.

VII. The respondent's arguments, in writing and during the oral proceedings, were as follows:

Admissibility of the opposition

In the notice of opposition it had been made credible that Werner & Pfleiderer had sold and delivered machine parts to Hüls AG for the modification of the extruder ZSK 120 without any secrecy obligation and that the method used during the subsequent start-up runs on the modified machine, which also were performed without any secrecy obligation, had become part of the prior art (see point 3 of the notice of opposition). Eight documents had been submitted as evidence for the alleged prior use. Whether these documents and the further submissions in the notice of opposition proved the alleged prior use was a matter of merit, not of admissibility.

Prior use "Hüls AG"

Werner & Pfleiderer had sold and delivered machine parts to Hüls AG for the modification of an extruder ZSK 120 in 1993. The main modification was replacing the existing die plate with a die plate having 384 holes with a diameter of 0.8 mm. Werner & Pfleiderer was a leading manufacturer in the field of extruders for industrial use. The delivery of machine parts to Hüls AG was an ordinary sale of replacement parts. It was a normal sale from a seller to a customer, not a cooperation between the seller and the customer. According to the case law of the Boards of appeal of the EPO a single sale to a single customer not subject to a secrecy agreement sufficed to prove a public prior use.

The test runs were part of a normal (paid) after-sale service programme, whereby Hüls AG had an interest to learn from the revised start-up procedure in view of the fact that earlier start-up procedures had failed. Employees of Hüls AG had been present during the test runs. The machine parameters with which the test runs were performed were documented on the last page (titled "Maschinendatenblatt") of document E8. It followed that not only the modified apparatus but also the method of running that apparatus was made available to the public.

Objection of lack of novelty

The test runs, which were performed without any secrecy obligation, constituted the act of prior use of a method having all the features of claim 1 of the main request. Consequently, the claimed method was not new.

Objection of lack of inventive step, a fresh ground for opposition?

On the Standard form EPO 2300 (Notice of Opposition to a European Patent), page 2, point VI (Grounds for opposition), the boxes indicating that the subject-matter of the European patent opposed is not new and does not involve an inventive step had been marked with a cross. In the decision under appeal it was found that claim 1 of the first auxiliary request did not involve an inventive step, Article 56 EPC (see point 4.4 of the Reasons). Lack of inventive step was thus not a fresh ground for opposition, and had to be examined by the Board even if the appellants did not agree.

Remittal to the first instance?

The patent application that matured into the patent in suit was filed in 1995. If the case were to be remitted to the first instance a further appeal by one or both of the parties could not be excluded, so that the legal uncertainty with respect to the status of the patent could possibly exist up to the end of its term.

Added subject-matter, a fresh ground for opposition?

Claim 1 of the first and third auxiliary requests differed from claim 1 as granted and from claim 3 as granted, respectively, in that the following feature had been added: "wherein the polyolefin resin contains talc as a nucleating agent". However, talc had only been disclosed as a nucleating agent in the amount of 0.01 parts by weight and only for an ethylene-propylene random copolymer, see page 3, lines 19 to 21, and page 4, lines 56 and 57, of the application as filed (published version). The subject-matter of claim 1 of the first and third auxiliary requests therefore extended beyond the contents of the application as filed, Article 123(2) EPC. Amendments of the claims in the course of opposition or appeal proceedings had to be fully examined as to their compatibility with the requirements of the EPC.

Objection of lack of inventive step

Main request (independent claims 1 and 3 as granted) and second auxiliary request (claim 3 as granted)

The object of the invention as stated in paragraph [0009] of the patent in suit, ie to provide a method for producing polyolefin resin granules having a higher uniformity of the dispersed compounding agents, was based on the use of a single-screw kneading extruder. The kneading extruder of the modified machine "Hüls AG" was a homodirectional twin-screw extruder which already solved the problems mentioned in said paragraph. The range claimed for the discharge amount per die nozzle hole of 2 - 8 Kg/hr was broad, since the minimum and maximum value differed by a factor of four, and encompassed all technically feasible throughputs. Document E14 disclosed a nozzle hole having a diameter of 2,2 mm, which was only 10% larger than the claimed maximum diameter of 2 mm, see page 179, last sentence. The given discharge amount per die nozzle hole of 6,8 Kg/hr was within the claimed range. The water temperature of an under water granulation cutter UG 200 was necessarily between 0 - 100ºC, since outside this range water was either solid (ice), or gas (vapour), and no longer liquid water. The range claimed for the water temperature of 5 - 90ºC was thus also broad. Document E14 disclosed a water temperature of 40 - 80ºC, ie within the claimed range. The range claimed for the difference between the water and resin temperatures was also broad, since a difference 140 - 220ºC meant that the resin temperature had to be in the range of 145 - 310ºC in order to fulfil said requirement. Since polypropylene had a melting temperature of about 160 to 165ºC (see eg document E16, page 781, upper Table, column "PP", row "Kristallitschmelztemp."), a person skilled in the art would select a temperature higher than the melting temperature and below the temperature at which the polypropylene was destroyed. The peripheral speed of the cutter blade for the under water granulation cutter UG 200 at 1500 rotations per minute was 15,7 m/s, ie within the claimed range. Producing pre-foamed beads of polyolefin resins for obtaining foamed articles was well-known in the art of extrusion of foamed products, see eg document E12, Section 13.2 on page 430, where foaming is mentioned as a consecutive production phase after extrusion, as is also acknowledged in eg paragraph [0002] and [0007] of the patent in suit. The subject-matter of claims 1 and 3 of the main request thus lacked an inventive step.

First and third auxiliary requests

Talc was a well-known nucleating agent in the art of extrusion of foamed products, see eg document E12, page 433, penultimate paragraph. The subject-matter of claim 1 of the first and third auxiliary requests therefore lacked an inventive step.