T 1071/17 30-01-2020

I. The opponent lodged an appeal against the interlocutory decision of the opposition division on the version in which European patent no. 2 632 689 meets the requirements of the European Patent Convention.

II. During the opposition proceedings, the opponent had raised the grounds for opposition according to Article 100(a) EPC in conjunction with Articles 54 and 56 EPC (lack of novelty and lack of inventive step).

III. Oral proceedings were held before the board of appeal on 30 January 2020.

IV. The appellant (opponent) requested that the decision under appeal be set aside and that the patent be revoked.

V. The respondent (patent proprietor) requested that the appeal be dismissed. In the alternative, it requested that the decision under appeal be set aside and that the patent be maintained on the basis of the claims according to any of auxiliary requests I, II or III, all filed on 21 November 2017 together with the reply to the statement setting out the grounds of appeal.

VI. The documents referred to in the appeal proceedings included the following:

E1: WO 2005/052049 A1

E2: WO 2006/018777 A1

E5: WO 2010/009832 A2

E11: Technical data sheet "Budit LM 16", Chemische Fabrik Budenheim KG, Budenheim, October 2008

E12: Safety data sheet "Iriotec", Merck KgaA, Darmstadt, 30 April 2015

E13: Safety data sheet "Copper(II) hydroxide phosphate", Sigma-Aldrich Chemie GmbH, Steinheim, 8 April 2013

E15: Material safety data sheet "Copper(II) phosphate", Alfa Aesar, Ward Hill (MA), 16 June 2009

E16: Excerpt from "Product Range", Chemische Fabrik Budenheim KG

VII. Claim 1 according to the main request reads as follows:

"Injection stretch blow molding process for preparing polyolefin containers, comprising the following steps:

1) preparing a preform by injection molding a polyolefin composition comprising a polymer (A) selected from ethylene polymers, propylene polymers and mixtures thereof, and a heat absorber (B);

2) supplying heat to reheat the preform prepared in step 1) and stretch blow molding said preform; characterized in that the heat absorber (B) is Cu2(OH)PO4."

VIII. Compared to the main request, claim 1 of auxiliary request I is amended as follows:

"Injection stretch blow molding process for preparing polyolefin containers, comprising the following steps:

1) preparing a preform by injection molding a polyolefin composition comprising an ethylene homopolymer or copolymer having density equal to or greater than 0.945 g/cm**(3) [deleted: a polymer (A) selected from ethylene polymers, propylene polymers and mixtures thereof], and a heat absorber (B);

2) supplying heat to reheat the preform prepared in step 1) and stretch blow molding said preform; characterized in that the heat absorber (B) is [deleted: Cu]2[deleted: (OH)PO]4 a copper hydroxide phosphate."

IX. In comparison with the main request, claim 1 of auxiliary request II is amended as follows:

"Injection stretch blow molding process for preparing polyolefin containers, comprising the following steps:

1) preparing a preform by injection molding a polyolefin composition comprising an ethylene homopolymer or copolymer having density equal to or greater than 0.945 g/cm**(3)and having F/E ratio values equal to or greater than 60 [deleted: a polymer (A) selected from ethylene polymers, propylene polymers and mixtures thereof], and a heat absorber (B);

2) supplying heat to reheat the preform prepared in step 1) and stretch blow molding said preform; characterized in that the heat absorber (B) is [deleted: Cu]2[deleted: (OH)PO]4 a copper hydroxide phosphate."

X. Compared to the main request, claim 1 of auxiliary request III is amended as follows:

"Injection stretch blow molding process for preparing polyolefin containers, comprising the following steps:

1) preparing a preform by injection molding a polyolefin composition comprising an ethylene homopolymer or copolymer having density equal to or greater than 0.945 g/cm**(3)**()[deleted: a polymer (A) selected from ethylene polymers, propylene polymers and mixtures thereof], and a heat absorber (B);

2) supplying heat to reheat the preform prepared in step 1) and stretch blow molding said preform; characterized in that the heat absorber (B) is Cu2(OH)PO4."

XI. The arguments of the appellant in the written and oral proceedings can be summarised as follows:

Main request, added subject-matter

The fact that the feature of claim 1 defining that the heat absorber (B) was Cu2(OH)PO4 did not make any reference to the specific product trademark "Budit LM16" was contrary to the requirements of Article 123(2) EPC. In the original application as filed it was not directly and unambiguously disclosed that this reference could be omitted. Rather, it required some considerations by the skilled person to realise that any Cu2(OH)PO4 could be used in the process of claim 1. In fact, as could be seen from documents E11, E12 and E13, Cu2(OH)PO4 sold under the name of "Budit LM16" differed from other Cu2(OH)PO4 products in its particle size distribution and purity, both of which had an important influence on the heat absorption properties relevant for the present invention. Moreover, documents E15 and E16 showed that, at the relevant date, not only Cu2(OH)PO4 but all three copper compounds mentioned on page 2 of the application as filed were commercially available, inter alia, from Budenheim. Finally, it was noted that also for examples 1 and 2 given in the patent application Cu2(OH)PO4 of the "Budit LM16"-type was used (see page 8 of the original application). In view of that, and according to the established case law of the boards of appeal, generalising this specific teaching to any Cu2(OH)PO4 product constituted an intermediate generalisation which went beyond what was directly and unambiguously disclosed in the application as filed.

Main request, inventive step

Document E2 was the closest prior art from which the subject-matter of claim 1 differed in that Cu2(OH)PO4 was used as heat absorber instead of carbon black. The problem solved by this difference resided in avoiding a dark coloration of the final articles (see contested patent, paragraph [0007]). The further advantages of an improved wall thickness distribution and a wider processing window constituted bonus effects. The claimed solution of using Cu2(0H)PO4 as heat absorber instead of carbon black and its advantages (very good heat absorption properties, preventing coloration of the moulded articles) was generally known from the prior art. In particular, document E1 (see page 2, lines 7 to 14 and 15 to 19, example 4 and Figure 2) disclosed that an heat absorber of the Mex(PO4)y(OH)z-type had outstanding heat absorption properties (thereby also allowing for a more energy efficient heating of the preforms) and avoided a dark coloration of the moulded articles (see E1, page 3, lines 1 to 12). Among the Mex(PO4)y(OH)z-type heat absorbers, Cu2(OH)PO4 was presented as the preferred choice (see E1, page 4, first paragraph and claim 5). In fact, all examples in document E1 were directed to Cu2(OH)PO4. This was a clear hint pointing the skilled person to the claimed solution. Moreover, document E1 (see page 3, lines 13 to 19 and claims 2 and 3) contained a list of polymers, including polyethylene and polypropylene, for which Cu2(OH)PO4 could be used as an heat absorber; this teaching was not altered by example 4, where Cu2(OH)PO4 was combined with PET for establishing the material properties in a standardised set-up. The fact that polypropylene had a particularly low heat absorption when compared to PET (see document E2, page 1, third paragraph) provided a further incentive for choosing Cu2(OH)PO4 as heat absorbing additive. In view of the teaching of document E1, a combination of documents E2 and E1 would (and not only could) guide the skilled person to the claimed invention.

Auxiliary requests I and II, admissibility

Compared with the request considered allowable by the opposition division, the last feature of claim 1 of the respondent's auxiliary requests I and II was generalised from "the heat absorber (B) is Cu2(OH)PO4" to "the heat absorber (B) is a copper hydroxide phosphate". This was contrary the principle of prohibition of reformatio in peius. Therefore, auxiliary requests I and II were inadmissible.

Auxiliary request III, admission

Auxiliary request III should not be admitted into the appeal proceedings. According the jurisprudence of the boards of appeal, convergence was a requirement for admitting amended claim requests into the appeal proceedings. This condition was not met for auxiliary request III.

Auxiliary request III, inventive step

Document E1 related to injection stretch blow moulding of PET bottles (see E1, page 1, third paragraph) and represented the closest prior art for the subject-matter of claim 1 of auxiliary request III. The claimed subject-matter differed from document E1 only in that the polymer was specified as comprising an ethylene homopolymer or copolymer having a density equal to or greater than 0.945 g/cm**(3). Since polyethylene was both lighter and cheaper than the PET material used in document E1, the objective technical problem to be solved was to provide an injection stretch blow moulding process for producing containers having a reduced density and lower costs. The claimed solution was rendered obvious by document E5, which also belonged to the technical field of injection stretch blow moulding. In particular, document E5 discussed the disadvantages of using PET and PP for blow moulded containers in terms of recycling (see E5, page 1, line 32 to page 2, line 8) and wall thickness distribution (see E5, page 2, lines 17 to 22) and proposed a two-step injection blow moulding process using HDPE (see E5, page 3, lines 16 to 24) in order to reduce the weight of the moulded containers (see E5, page 4, lines 7 to 12) and to improve their recyclability. It was explicitly stated that PET and HDPE were comparable in terms of shrinkage (see E5, page 3, lines 29 to 35) and that the existing injection moulds for PET preforms could also be used for HDPE (see E5, page 3, lines 35 and 36). Changing the plastic material did thus not require any investment in new moulding equipment. Consequently, document E5 motivated the skilled person to replace the PET material used in the process of document E1 with HDPE without having to expect any difficulties. The additive Cu2(OH)PO4 used in the process of document E1 could be generally utilised as heat absorber independently of the type of polymer. The skilled person would therefore naturally combine it with the HDPE material proposed in document E5. For these reasons, the subject-matter of claim 1 of auxiliary request III was rendered obvious by a combination of documents E1 and E5.

XII. The respondent's written and oral submissions may be summarised as follows:

Main request, added subject-matter

The penultimate paragraph on page 2 of the application as filed listed three specific examples of an heat absorber and identified these chemical compounds by their respective CAS number. Further, the paragraph stated that one of these compounds, namely Cu2(OH)PO4, was sold by Budenheim under the trademark of "Budit LM16". The reader of the text was hence informed that one of these compounds was commercially available and one source for this compound was identified. Contrary to the appellant's assertions, this paragraph did not give the impression that the specific example was the product sold under the tradename "Budit LM16". The paragraph in question listed three chemical compounds and complemented the information with a purchase option for one of them. Accordingly, the amendment of claim 1 was directly and unambiguously derivable from the application as originally filed and did thus not introduce subject-matter which extended beyond the original content of the application.

Main request, inventive step

Document E2 represented the closest prior art, from which the subject-matter of claim 1 differed in that Cu2(OH)PO4 was used as an heat absorber. The objective technical problem was to find a process for producing polyolefin containers by an injection stretch blow moulding process in which the obtained containers had reduced variations in the wall thickness in combination with a large processing window, of course without having a dark coloration of the final articles. Documents E1 would not have prompted the skilled person to modify the disclosure of document E2 in a way to arrive at the subject-matter of claim 1, in the expectation of obtaining an improved injection stretch blow moulding process for ethylene polymers, propylene polymers or mixtures thereof which gave a better wall thickness distribution and had a wider processing window. Document E1 disclosed in its introductory portion that PET bottles could be prepared in an injection stretch blow moulding process. However, document E1 was silent on the wall thickness distribution, energy consumption and processing window, even for the PET process. In view of that, document E1 could clearly not point the skilled person to using Cu2(OH)PO4 as an heat absorber in ethylene polymers, propylene polymers or mixtures thereof. Moreover, the examples did not relate to injection stretch blow moulding. Example 4 of document E1 was directed to small plates prepared by injection moulding. Hence, a combination of documents E2 and E1 would not render obvious the subject-matter of claim 1.

Auxiliary requests I and II, admissibility

The respondent did not wish to comment on the appellant's objection of a violation of the principle of prohibition of reformatio in peius.

Auxiliary request III, inventive step

Document E5 was a reasonable starting point for examining the question of inventive step. Injection stretch blow moulding was customarily done with PET or PP, while processing HDPE in injection stretch blow moulding was difficult. Document E5 indicated a possibility of performing injection stretch blow moulding with a specific HDPE composition. This prior art teaching was reflected in comparative example 1 of the patent in suit (see Table 1 in paragraph [0058]) and had the disadvantage of a high scrap rate, i.e. a high percentage of defective bottles. The problem to be solved by the present invention thus was to improve the processing window and the cost effectiveness of injection blow moulding of HDPE containers. The claimed solution resided in adding Cu2(OH)PO4 as an heat absorber to the HDPE polymer. Document E5 did not contain any indication to that effect. Therefore, a combination of documents E1 and E5 could not render obvious the subject-matter of claim 1 of auxiliary request III.