T 0210/08 12-02-2010

I. Mention of the grant of European Patent No. 0 952 993 with the title "Polymerisation Process" in the name of BP Chemicals Limited, later Ineos Europe Limited, in respect of European patent application No. 98900555.8, filed on 7 January 1998 as international application No. PCT/GB1998/000039, published as WO-A1-98/30605 on 16 July 1998, and claiming a priority date of 13 January 1997 from EP 97430001.4 was announced on 6 October 2004 (Bulletin 2004/41) on the basis of 14 claims.

Claim 1 read as follows:

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Claims 2 to 14 were dependent claims, directed to preferred embodiments of the process of claim 1.

II. A notice of opposition to the patent was filed on 5 July 2005 by Basell Polyolefine GmbH.

The grounds of opposition pursuant to Art. 100(a) EPC (lack of novelty, lack of inventive step), Art. 100(b) EPC (insufficiency of disclosure) and Art. 100(c) EPC (extension of the subject-matter of the patent beyond the content of the application as filed) were invoked. The following document was, inter alia cited in support of the opposition:

D1: WO-A-94/25497.

III. In a decision dated 21 November 2007 and posted on 29 November 2007 the opposition division revoked the patent on the grounds pursuant to Art. 100(c)/123(2) EPC.

The decision was based on the patent in the form as granted.

(a) The feature of claim 1 that the process was operated in a "non-condensed mode", which had been introduced into the claims during the examination procedure, was not explicitly disclosed in the application as filed.

(b) The disclosure of the processes at page 8, line 22 to page 9 line 5 of the original application, invoked by the patent proprietor as providing a basis for this amendment, would be understood by the skilled person as relating to operation in a condensed mode. Consequently the skilled reader would conclude that the process of the invention was carried out in the condensed mode rather than in the non-condensed mode.

(c) There was nothing in this passage nor elsewhere in the description which indicated that the process might be worked in a non-condensed mode or above the dew point of the gas mixture. The description did not permit it to be understood that the specific process (where the condensed mode was excluded) had ever been intended to be the invention.

(d) Examples 3 to 6 of the original application also could not serve as a basis for this amendment to claim 1. The examples were carried out as a batch process. Claim 1 however was directed to polymerisation processes in general (i.e. batch and continuous processes). Thus even if it were clear for the skilled person that the examples had been carried out in a non-condensed mode (because there was no mention of a liquid phase) the amendment to claim 1 resulted in an inadmissible generalisation.

(e) Since the main request did not meet the requirements of Art. 123(2) EPC the patent was revoked.

(f) The decision (and minutes) further records that at the oral proceedings before the opposition division the patent proprietor had been asked if it wished to file a further request and stated that it did not.

IV. A notice of appeal against the decision was filed by the patent proprietor on 28 January 2008, the prescribed fee being paid on the same day.

V. The statement of grounds of appeal was filed on 25 March 2008.

The arguments advanced can be summarised as follows:

(a) Although the expression "operating in a non-condensed mode" was not present word for word (emphasis of the appellant/patent proprietor) in the application as filed the skilled person would readily understand the meaning of the expression which was also derivable from a reading of the application as filed.

(b) The phrase "operating in a non-condensed mode" merely limited the protection for the subject matter of the claims by removing part of the protection conferred by the application as filed since gas phase processes which operated in a condensed mode were not/no longer covered by the claims of the patent, reference being made to G 1/93 (OJ EPO 1994, 541).

(c) The disclosure implicit in the patent application, i.e. what any skilled person would consider as necessarily implied by the patent application as a whole in view of basic scientific laws, was relevant for the requirements of Art. 123(2) EPC, reference being made to the findings of T 860/00 (28 September 2004, not published in the OJ EPO).

The application as filed disclosed that the process could be carried out in any suitable gas phase process and included specific descriptions of processes which were known as condensed phase processes, reference being made to four patent documents in the application (EP 89 691, EP 699 212, EP 784 637 and WO 94/28032).

(d) A further disclosure of condensed mode operation was to be found in D1 which disclosed at page 2 lines 1-5 that "the process of purposefully introducing a recycle stream having a liquid and a gas phase into a reactor such that the weight percent of liquid based on the total weight of the recycle stream is greater than about 2.0 weight percent is defined to be operating a gas phase polymerisation process in a condensed mode".

(e) From all these publications it was clear that a condensed mode of operation had to comprise mandatorily the following elements:

- gas phase;

- fluidised bed;

- continuous process;

- cooled recycle stream;

- gas and liquid phase;

- liquid recycled to the reactor.

As was apparent from the four documents mentioned in the description of the application and patent in suit there could also be variants within this definition.

(f) The skilled person would therefore have no doubt as to the meaning of the term "condensed mode operation" and consequently would clearly understand operation in "non-condensed mode" as required by the claims of the patent in suit.

(g) The phrase "operating in a non-condensed mode" was thus implicitly derivable from the application as filed in a clear and unambiguous manner.

(h) Submissions were also made with respect to novelty and inventive step, which however are not of relevance to the present decision.

(i) An auxiliary request was also submitted, claim 1 of which read as follows:

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VI. The opponent - now the respondent - replied with a letter dated 6 October 2008 and argued essentially as follows:

(a) The expression "said process operating in a non-condensed mode" lacked full support in the application as filed.

(b) This feature could not be deduced directly and unambiguously from the implicit disclosure of the application as filed (with reference to T 860/00, cited in the statement of grounds of appeal).

(c) The argument of the appellant that the passage starting at page 8 and continuing onto page 9 of the application as filed would describe a process known as "condensed mode operation" was disputed.

There was no way that the meaning of "condensed mode operation" could be unambiguously construed from the application as filed.

The passage invoked by the appellant/patent proprietor stated that the process could be carried out in any suitable gas phase process and referred to two particular types of fluidised bed processes.

The first type entailed cooling of the recycled gas stream and returning the cooled recycled stream containing entrained liquid to the fluidized bed beneath the fluidization grid. The second type entailed cooling of the recycled gas stream, separating the entrained liquid and feeding it directly to the fluidised bed. The appellant/patent proprietor had artificially clustered these two types of processes to form a homogeneous group having a number of features (see section V.(e), above).

Reference to D1 would exclude the second type of process, i.e. wherein the liquid was separated and then reintroduced to the reactor. In any case in view of D1 the skilled person would be uncertain whether a process employing a weight of recycle stream of lower than 2.0 weight percent would qualify as condensed mode or not.

(d) The lack of direct and unambiguous support was even more pronounced when it came to the language in question, namely "operating in a non-condensed mode" (emphasis of the respondent/opponent). By referring to the definition of condensed mode operation given by the appellant/patent proprietor a polymerisation process in non-condensed mode would be intended as a gas phase fluidised bed continuous polymerisation process wherein the cooling of the gaseous recycle stream before reintroducing it into the reactor was made by maintaining the temperature above its dew point, i.e. without having condensation of part of the recycle stream. This was however neither explicitly or implicitly disclosed.

(e) Further the skilled person was faced with the ambiguity of deducing from the application as filed whether the definition "operating in a non-condensed mode" would include or exclude stirred bed and discontinuous processes. In the former case there would be an inadmissible generalisation of the condensed mode feature since it had been at most disclosed in association with fluidised bed continuous processes; in the latter case the limitation "non-condensed mode" would be rendered senseless and would result in all working examples not supporting the invention.

(f) The respondent/opponent disputed the arguments of the appellant/patent proprietor with respect to G 1/93.

According to T 384/91 (OJ EPO 1995, 745) a feature should not be considered as merely limiting the protection conferred (i.e. without providing a technical contribution) if it interacted with the remaining features of the claim so influencing the solution of the technical problem derivable from the application as originally filed. In view of the problem as set out at page 2 lines 12-14 of the application as filed, namely improving catalytic activity of the metallocene catalyst systems in gas phase processes, it followed that an evident interaction existed between the added limitation (operation in the non-condensed phase) and the solution represented by the injection of an inert liquid (emphasis of the respondent/opponent) into the reactor. Addition of a liquid would clearly produce different results in a gaseous environment (non-condensed mode) than if a liquid was already present (condensed mode).

(g) Objections were also raised with respect to the auxiliary request which are however not of relevance to the present decision.

VII. On 17 November 2009 the Board issued a summons to attend oral proceedings.

VIII. Oral proceedings were held before the Board on 12 February 2010.

(a) At the commencement of the oral proceedings the appellant/patent proprietor withdrew the auxiliary request filed together with the statement of grounds of appeal (see section V.(i), above) and announced that a new auxiliary request would be presented in the course of the oral proceedings.

(b) With respect to the main request the appellant/patent proprietor essentially reiterated the submissions made in the statement of grounds of appeal.

Whilst the disputed wording - "non-condensed mode" - was not present in the application as filed the skilled person would understand the meaning thereof, this being derivable from the application as filed.

In particular, the reference to a recycle line at page 8 lines 25-30 of the application as filed would be understood implicitly to relate to the non-condensed mode of operation with no cooling below the dew point of the gaseous diluent stream. The examples were provided to demonstrate the improved effect of the invention in the context of standard laboratory scale apparatus and conditions representative of larger scale processes, but not to provide support for the full possible scope thereof.

The amendment was further in line with the findings of G 1/93 since the feature "non-condensed mode" merely excluded protection for part of the original scope and conferred no advantage on the patent proprietor.

(c) The opponent/respondent emphasised that there was no disclosure of non-condensed mode operation in the application as filed and maintained the position as set out in the written submissions that there was no clear definition either in the application as filed or on the basis of common general knowledge of what was to be understood by "condensed mode operation" (see section VI.(c), above).

Even if the disclosure of the application as filed would be understood by the skilled person as relating to operation in the condensed mode it was not clear how the further step to a non-condensed mode could be made on the basis of these disclosures nor what this would mean.

According to the logic of the appellant/patent proprietor (see section V.(e), above) the term "condensed mode" related to a process exhibiting a certain combination of parameters. Following this reasoning, any process lacking a single one of these parameters would have to be considered as "non-condensed mode".

However even following this logic the examples still would not provide support for the claims since they lacked all indicated features from pages 8-9 of the application as filed except for gas phase operation.

The objections raised with respect to decision G 1/93 were reiterated (See section VI.(f), above).

(d) The appellant/patent proprietor emphasised that there was no ambiguity concerning what was meant by "condensed mode" operation. Although this had variations, as shown by the passage on Page 8-9 of the application it nevertheless had a set number of features. It was necessary to employ commonsense and focus on these features.

With respect to G 1/93 it was submitted that there was no evidence that the effect of the addition of alkane would be different depending on the environment within the reactor. It was in any case known that in condensed mode operations addition of liquid provided certain advantages - namely improved productivity as the liquid cooled the bed improving the output.

The invention related generally to gas phase systems and showed that addition of alkane improved catalyst activity which, it was stressed, did not necessarily mean that the production rate was improved. The technical effect relied upon arose solely due to the addition of lower alkane into the reactor. Once in the reactor this became gaseous - regardless of the form in which it had been introduced. Thus the effect of the invention arose from introduction of the alkane per se and was not associated with the mode in which the reactor was operated (condensed or non-condensed mode) or with the form in which the alkane was introduced.

The examples together with the teaching on page 8 of the application showed that operation in a non-condensed mode was clearly intended since certain of the embodiments disclosed on page 8 would be understood as operating in the non-condensed mode. The absence of any evidence to support this position was due to the fact that at the time of filing the application the invention was not focussed on this point.

(e) The opponent disputed that adding inert liquid to the reactor would not interact with the remaining features of the claim. It was clear that adding liquid into an environment with no liquid would have an effect different from that in an environment where liquid was already present. Neither "non-condensed mode" nor the requirement that the temperature of the recycle stream be kept above the dew point was explicitly or implicitly disclosed in the application as filed.

(f) Following conclusion of discussion on the main request, the new auxiliary request, announced at the commencement of the oral proceedings (see section VIII.(a), above) was submitted.

This request consisted of 13 claims.

The appellant/patent proprietor explained that claim 1 had been amended by incorporation of the features of original claim 10 thus restricting the scope of the claims to fluidised bed polymerisation.

Claim 1 of this request thus read as follows:

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This request had only been filed at the oral proceedings before the Board because instructions had only very recently been received.

It had not been filed in direct response to any action of the respondent/opponent during the appeal proceedings, but to take account of submissions made in the opposition proceedings and comments of the opposition division that claim 1 was an over-generalisation.

The amendment was straightforward in particular as much of the debate concerning the main request related to the aspects of fluidised bed reactors and condensed/non condensed modes.

(g) The respondent/opponent apart from disputing that this request was allowable objected to this as late filed. The appellant/patent proprietor had had ample time to submit such a request. As followed from the decision under appeal the patent proprietor had at the oral proceedings before the opposition division been given the opportunity to submit a further request but declined to do so (see section III.(f), above). A new request had however been filed with the statement of grounds of appeal, which request had been dealt with in the rejoinder to the statement of grounds of appeal. The appellant/patent proprietor should have submitted the new auxiliary request at least one month before the oral proceedings in order to give the respondent/opponent the opportunity at least to carry out a formal check.

The respondent/opponent indicated that it would require time to consider the request in detail and to prepare its response.

IX. The appellant (patent proprietor) requested that the decision under appeal be set aside and the patent be maintained as granted, or, in the alternative, that the patent be maintained on the basis of the Auxiliary Request (claims 1-13) filed at the oral proceedings.

The respondent (opponent) requested that the appeal be dismissed, or, in the case that the decision under appeal is set aside, that the case be remitted to the first instance for further prosecution.