T 0359/96 16-06-1998

Reasons for the Decision

1. The appeal complies with the formal requirements of Articles 106 to 108 and Rules 1(1) and 64 EPC. It is therefore admissible.

2. The original application (subsequent page references are to the published A-document) begins with an exposition of the characteristics required of a refillable plastics bottle, in particular the necessity for the bottle to retain certain properties, especially fill level volume, impact breakage resistance and transparency, over at least five re-use cycles. It is then indicated that of potentially usable commercially available polymers polyethylene terephalate (PET) is considered the best. There follows an explanation in general terms as to why conventional methods for making non-returnable PET beverage containers cannot be used to make returnable containers.

The fairly extensive particular description of the application is somewhat unusual, at least for this area of technology, in that it resembles a scientific research report setting out the various stages of development on the route towards a commercially and functionally viable returnable PET container. Original claim 1 is also unusual in that it is directed to any polyester container of conventional blow-moulded form which is capable of maintaining viability over a minimum of five usage loops comprising the steps of caustic washing, product filling, storage, distribution, end use and return, the claim however not specifying any technical features by which this goal is to be achieved.

To a certain extent it is undoubtedly the nature of original claim 1 which has led to the plethora of objections of added subject-matter in the present case since, in the course of the examination proceedings, it was necessary to fill the essentially empty vessel of that claim with technical content by the incorporation of various features, the original basis for many of which has given rise to dispute.

Some of the areas of dispute with respect to granted claim 1 have been dealt with by amendment. Two of these amendments are wholly uncontentious. These concern the elimination of the broadening term "on the order of" from before the given range of 0.72 to 0.84 of the intrinsic viscosity of the PET and the ratio of 7 to 9 between the preform body wall thickness and the container body thickness. The third amendment concerns the replacement in granted claim of the reference to a "bottom wall (34)" by a reference to a "champagne-type base (34)", this base being further defined in the preamble of the claim as "including a chime area (40) having a peripheral contact radius and an unoriented recessed central portion". This amendment has given rise to an objection under Article 123(3) EPC to the effect that it was not clear that the bottom wall and the champagne-type base were necessarily one and the same part of the container. In this context the Board notes that the term "bottom wall" does not as such appear in the original disclosure and appears to have been generalised from the only form of container base actually illustrated there, which was of the champagne-type. Furthermore, granted dependent claim 5 states that "said container bottom (34) has a champagne-type base (34) including a peripheral contact radius (32) and an unoriented recessed central portion". From a consideration of the above it is apparent that the champagne-type base now defined in the amended main claims is a preferred embodiment of the bottom wall defined in granted claim 1, so that the replacement of the latter term by the former cannot constitute an inadmissible extension of the scope of protection contrary to Article 123(3) EPC. The more complex question of whether the references in the amended claims to the degree of orientation of the champagne-type base conform with the requirements of Article 123(2) EPC is dealt with in more detail below.

3. The three aspects of claim 1 of the main request which have been the most contentious as regards the question of added subject-matter are the requirement that the base of the container be "rigid" and the sidewall "flexible", the requirement that the base have "a low orientation and the requirement that the sidewall has "up to 30% crystallisation".

3.1. Turing first to the issue of the rigidity of the base of the container, it is clear from the original application that the purpose of the form of the base disclosed, which is of a relatively thick "champagne-type" shape, is to provide a firm footing for the container when this is standing upright. To achieve this it is evident to the person skilled in the art that the base must be "rigid" as this term would be understood in the field of blow moulding PET containers.

As regards the flexibility of the sidewall of the container it is necessary to draw a distinction between two different lines of argument of the appellants. The first, which was dominant in the Statement of Grounds of Appeal but which has now slipped somewhat into the background, is that the term "flexible" would be comprehended by the person skilled in the art as meaning capable of being readily deflected inwardly by manual squeezing when the container is in an unfilled state and that there was an implicit teaching of this in the original application. Here, the appellants relied to a large extent on the dimensions of the 1.5 litre bottle portrayed as the preferred embodiment of the invention. The second line of argument, advanced forcefully in the submissions of the appellants dated 12. May 1998 and at the oral proceedings, is that the flexibility of the sidewall has to be judged in relation to the rigidity of the base.

The Board has little difficulty in accepting, given the overall size of the illustrated 1.5 litre bottle and the fact that the thickness of its sidewall is only slightly more than 0.6 mm, that this sidewall is indeed flexible in the sense put forward by the appellants. But this is not the decisive issue. The point is that the claim under consideration specifies neither the overall size of the container, nor the thickness of its sidewall and there is nothing to be found in the original application which could be seen as giving a clear teaching to the person skilled in the art that all containers falling within the ambit of the invention disclosed there should have such a flexible sidewall. The first line of argument of the appellants therefore fails. Their second line of argument is however more compelling. As explained on page 4, at lines 29 to 38, the container is blow moulded from a specially designed preform in such a way as to produce a continuously reinforced base which is relatively thick in comparison with the sidewall. It is also stated in this passage that although the actual thickness of the base and sidewall may be varied the thickness ratio (which in the embodiment of Figure 5 is of the order of seven to one) should remain constant. In the opinion of the Board the person skilled in the art would recognise from this, even taking into account other factors (higher orientation, higher crystallisation) which might increase the inherent stiffness of the material of the sidewall over that of the base, that the sidewall would be significantly more flexible than the rigid base (see above). This difference in flexibility would be wholly commensurate with the different roles the base and the sidewall are expected to play in the use of the container. To this extent, therefore, the Board has come to the conclusion that the requirement of claim 1 of the main request that the sidewall be flexible does not offend against Article 123(2) EPC.

3.2. The next objection to be considered under this heading is the requirement that the base has a low orientation. Here, in contrast to the objection to the terms rigid and flexible considered above, the problem lies not so much in the fact that the term "low orientation" does not appear in the original application, although that is indeed the case, but more in the fact that this term is arguably inconsistent with what is to be found there. In particular, the original application contains clear statements, for example in claim 8, that the recessed central portion of the champagne-type base is "unoriented" and furthermore the last paragraph on page 5 of the description, although somewhat unclear in its terms, could be interpreted as meaning that the whole of the base is "unoriented". However, the Board takes the view that such an interpretation of this passage would not be consistent with the technical realities of the stretch blow moulding process used to manufacture the container, which process must inevitably lead in regions of the base radially outside the recessed central portion to progressively increasing amounts of stretch in the material of the base and thus to its orientation. The amount of this orientation will however always be significantly less than that of the sidewall of the container. It is therefore apparent that, considered as a whole, the base of the container can be fairly said to have "low orientation", even though, as now clearly stated in claim 1 of the main request, (see point 2 above) its recessed central portion is unoriented. Thus also this objection under Article 123(2) EPC does not hold good.

3.3. The last issue to be considered in this section is the requirement of claim 1 of the main request that the sidewall have "up to 30% crystallisation". In the last two paragraphs of page 4 and in the passage at lines 1 to 18 of page 5 of the description of the original application there is a discussion of the need to reduce the container volume change to below ±1.5% and the step adopted to achieve this, namely the use of "recently developed technology" to produce containers with a 24-30% crystallinity level with improved thermal stability (i.e. resistance to shrinkage at elevated temperatures) in comparison with containers produced by conventional non-returnable PET bottle technology (page 5, lines 15 to 18). On page 6, at lines 24 to 33, there is then a discussion of an investigation as to whether there would be any advantage in increasing the crystallinity level above 30% and the conclusion drawn that there would not be. This is then followed by the statement that "under the circumstances, it is believed that 24-30% crystallinity is an optimum level". This range of sidewall crystallinity is the subject of original dependent claim 5.

In the opinion of the Board the description of the original application, when read as a whole, gives the person skilled in the art the clear teaching that in order to achieve a functionally viable returnable PET container it is necessary to adopt special measure to achieve a certain minimum level of crystallinity in the sidewall, that minimum level being 24%. On the other hand, the passages on page 6 particularly relied upon by the appellants as demonstrating that the skilled person is merely instructed to keep the crystallinity level below 30% can only be seen as indicating that there was thought to be no point in going above this level. There is nothing here to support the contention of the appellants that the person skilled in the art would see in these passages a teaching that the previously discussed special measures for increasing crystallinity of the sidewall and hence thermal stability of the container were not in fact necessary.

The appellants have also argued that the appearance of the range of 24-30% crystallisation in a dependent claim indicates that this was only a preferred feature of the invention. There are no doubt cases where this argument might hold good but, given the nature of the original claim 1, see point 2 above, this does not appear to be one of them. In any case, even if the range of 24-30% crystallisation were indeed to be seen as being merely preferred rather than essential, this would not in itself provide a proper basis for the requirement of "up to 30%" crystallisation under consideration.

The Board has therefore come to the conclusion that claim 1 of the main request falls at this hurdle, so that the main request must be rejected in accordance with Article 123(2) EPC. The "alternative" main request, which differs from the main request only in respect of the limitation to the range of from 24 to 30% crystallisation, is however allowable in this regard.

4. Having dealt with the three most contentiously argued aspects of the conformity of the claims with Article 123(2) EPC it is still necessary to deal with the remaining objections.

The first of these is that the original application did not teach that the container as claimed was "transparent". There is however a clear statement on page 2, at line 17, than an ideal returnable container should be "transparent" and there can be no doubt that the containers produced according to the detailed instructions contained in the particular description of the application would indeed have this quality.

The second objection is that there was no teaching in the original application as to the stress crack resistance of the containers. However, the problem of stress cracking is discussed extensively on page 4 of the application, together with the measures taken to give the necessary stress crack resistance.

The last of the objections is to the use of the term "moderate" to qualify the value of the intrinsic viscosity of the PET, now stated to be between 0.72 to 0.84. Given the restriction to that range it seems substantially irrelevant to the Board whether the term "moderate" is appropriate to qualify it. Certainly, there can be no suggestion of an addition of subject-matter through the use of the term in this context.

5. Having regard to the above, the Board is of the opinion that claim 1 according to the alternative main request does not offend against Article 123(2) EPC.

Since the substantive issues of novelty, inventive step and sufficiency of disclosure have not yet been addressed by the Opposition Division the Board makes use of its power under Article 111(1) EPC to remit the case to the first instance for further prosecution.

For the avoidance of any doubt the Board emphasises that it has made no analysis of the appropriateness of the two-part form of the claim and that its approval of the claim as a basis of further prosecution is not intended to be taken as a confirmation of the fact, for example, that a flexible container sidewall is a distinguishing feature over the closest state of the art. In fact, the appellants have explicitly recognised that it may become necessary to adjust the two-part form of the claim one the closest state of the art has been identified and evaluated.

6. According to Article 112(1)(a) EPC a Board of Appeal shall, following a request from a party, refer any question to the Enlarged Board of Appeal if it considers that a decision is required in order to ensure uniform application of the law, or if an important point of law arises.

In the course of the oral proceedings the first appellants (opponents 01) requested that the question set out in section VI above be referred to the Enlarged Board of Appeal.

However, the question which has been formulated concerns not a question of law, but one of language, and furthermore is so closely associated with the specific details of the present case that is not of general interest. In any case, the premise on which the question is built, namely that certain features ("wording") were not originally disclosed, does not apply in the present case so that the Board does not need to have the question answered before it can take its decision. Thus none of the pre-requisites for a referral of a question to the Enlarged Board of Appeal are present and the request is therefore rejected.