T 1321/05 14-05-2008

I. Mention of the grant of European patent No. 0 883 658 in respect of European patent application No. 97 902 947.7 filed on 16 January 1997 as International application PCT/US97/00626 (WO 97/31077) in the name of Minnesota Mining and Manufacturing Company was announced on 15 November 2000 (Bulletin 2000/46).

II. The patent, entitled "Graphic marking films comprising pressure sensitive adhesive" was granted with eleven claims. Claims 1 and 11 read as follows:

"1. A graphic marking film comprising:

(a) a film sheet having first and second surfaces; and

(b) an acrylate copolymer pressure sensitive adhesive system applied to one of the first and second surfaces, the acrylate copolymer pressure sensitive adhesive composition comprising:

(i) 100 parts by weight of an acrylate copolymer pressure sensitive adhesive comprising:

1) from 70-98% by weight of one or more monofunctional acrylates having nontertiary alkyl groups with between 1 and 14 carbon atoms; and

2) from 30-2% by weight of a polar monomer;

(ii) 1-10 parts dry weight of a plasticizer; and

(iii) optionally, a crosslinking agent for the adhesive."

"11. A method of applying the graphic marking films of any of claims 1-10 to a surface at a temperature below 40ºF (4.4ºC).

Claims 2 to 10 were, either directly or indirectly, dependent on Claim 1.

III. On 15 August 2001 opposition against the patent was filed by

Avery Dennison Corporation.

The opposition was based on the opposition grounds according to Articles 100(a) and 100(b) EPC.

The Opponent requested revocation of the patent in its entirety because the subject-matter claimed was not novel and lacked an inventive step (contrary to Articles 54 and 56 EPC) and the invention was insufficiently disclosed (contrary to Article 83 EPC).

The Opponent based its objections as to lack of novelty and lack of inventive step inter alia on the following documents:

D1 US-A 4 985 488

D2 US-A 5 049 608

D6 US-A 5 229 207.

Furthermore, the Opponent alleged that the four products "FasCal 900 Containerfilm", "FasCal 1900 SST Repositionable Construction", "FasCal 4900-AP Construction" and "FasCal CT-5900" comprising a film sheet and a pressure sensitive adhesive system as claimed were available on the market before the effective priority date of 26 February 1996. Numerous exhibits marked "B", "E" and "N" were filed as evidence.

IV. The Patent Proprietor defended the patent as granted and filed, with the letter dated 27 September 2004, sets of claims as bases for auxiliary requests 1 to 6.

In the oral proceedings before the Opposition Division, which were held on 13 July 2005, the Proprietor submitted an amended auxiliary request 1 consisting of twenty six claims. The set of claims according to this request differed considerably from the granted claims in that two new independent Claims 9 (with Claims 10 to 17 dependent thereon) and 18 (with Claims 19 to 26 dependent thereon) were added.

Claim 1 of the amended auxiliary request 1 corresponded to Claim 1 as granted with the amendment

- that the film sheet was limited to "a film sheeting selected from the group consisting of plasticized flexible polyvinyl chloride, polyacrylates, polyurethanes, perfluoropolymers, polycarbonates and retroreflective sheeting" and

- that the plasticizer was limited to a plasticizer "selected from the group consisting of polyoxyethylene aryl ethers, adipate esters, 2-ethylhexyl diphenyl phosphate, t-butylphenyl diphenyl phosphate, toluene sulfonamide, dipropylene glycol dibenzoate, polyethylene glycol dibenzoate, polyoxypropylene aryl ethers, and dibutoxyethoxyethyl formate".

Claim 9 was directed to a method of applying a graphic marking film to an irregular surface, wherein the film sheeting and the plasticizer were limited as in Claim 1 above.

Claim 18 was directed to a graphic marking film bonded to a vehicle,

- wherein the film sheeting was unlimited, as in Claim 1 as granted and

- wherein the plasticizer was limited as in Claim 1 above.

V. With its interlocutory decision announced in the oral proceedings and issued in writing on 20 September 2005, the Opposition Division maintained the patent on the basis of the above amended auxiliary request 1.

The main request was considered to be not allowable because, in the Opposition Division's view, the subject-matter of Claim 1 as granted lacked novelty over D1.

As regards amended auxiliary request 1, its subject-matter was considered to be new, inter alia over D2, because the list of plasticizers was not disclosed in this document.

The Opposition Division also acknowledged inventive step of this subject-matter over a combination of D2 as the closest prior art and D6. In its view, the problem to be solved according to D2, namely to overcome blistering and film lifting, was different from the problem to be solved according to the invention, and D6 did not disclose the claimed plasticizers as a component of an adhesive system.

There was also no reason to combine D2 with other documents, like D1, in order to arrive at the low temperature effect of the claimed graphic marking film demonstrated in the patent with the polyoxyethylene aryl ether plasticizer Pycal® 94.

The alleged prior public use was considered to be not relevant.

The Opposition Division also acknowledged that the invention claimed in amended auxiliary request 1 was sufficiently disclosed in accordance with Article 83 EPC.

Furthermore, the limitation of the film sheeting/plasticizer and the addition of the new Claims 9 and 18 were considered allowable under Articles 123(2) and 123(3) EPC.

VI. Appeals against the decision of the Opposition Division were filed:

- by the Opponent on 15 August 2005 (ie before issuance of the decision in writing); - the Statement of the Grounds of Appeal was filed on 25 January 2006;

- by the Patent Proprietor on 28 November 2005; - the Statement of the Grounds of Appeal was filed on 30 January 2006.

VII. The Appellant/Opponent reiterated its objections as to lack of novelty, lack of inventive step and insufficiency of disclosure and further submitted that Claims 18 to 26 of the claim-set as allowed by the Opposition Division lacked clarity, contrary to Article 84 EPC, extended the scope of the patent, contrary to Article 123(3) EPC, and were not occasioned by an opposition ground, contrary to Rule 57(a) EPC 1973 (corresponding to Rule 80 EPC). Furthermore, the objection was raised that the introduction of the list of plasticizers into Claim 1 was an amendment which had no support in the application as filed, contrary to Article 123(2) EPC.

VIII. The Appellant/Proprietor defended, as a main request, the patent as granted, alternatively maintenance of the patent on the basis of auxiliary request 1 as allowed by the Opposition Division, and filed, with its letter dated 18 September 2006, further sets of claims as bases for auxiliary requests 2 to 6.

In the oral proceedings held on 14 May 2008 the Appellant/Proprietor replaced auxiliary requests 1 to 6 by new auxiliary requests 1 to 5, after the Board had expressed its opinion that a number of amendments to the claims were not occasioned by an opposition ground, contrary to Rule 80 EPC.

Claim 1 according to the new auxiliary request 1 reads as follows:

"1. A graphic marking film comprising:

(a) a film sheeting selected from the group consisting of plasticized flexible polyvinyl chloride, polyacrylates, polyurethanes, perfluoropolymers, polycarbonates and retroreflective sheeting,

the film sheeting having first and second surfaces; and

(b) an acrylate copolymer pressure sensitive adhesive system applied to one of the first and second surface, the acrylate copolymer pressure sensitive adhesive composition comprising:

(i) 100 parts by weight of an acrylate copolymer pressure sensitive adhesive comprising:

1) from 70-98% by weight of one or more monofunctional acrylates having nontertiary alkyl groups with between 1 and 14 carbon atoms; and

2) from 30-2% by weight of a polar monomer;

(ii) 1-10 parts dry weight of a plasticizer; and

(iii) optionally, a crosslinking agent for the adhesive,

wherein the plasticizer is selected from the group consisting of polyoxyethylene aryl ethers, adipate esters, 2-ethylhexyl diphenyl phosphate, t-butylphenyl diphenyl phosphate, toluene sulfonamide, dipropylene glycol dibenzoate, polyethylene glycol dibenzoate, polyoxypropylene aryl ethers, and dibutoxyethoxyethyl formate."

Independent Claim 9 of this request is directed to a method of applying a graphic marking film comprising applying the graphic marking film to an irregular surface at a temperature below 4.4ºC (40ºF). The graphic marking film is characterized as in Claim 1.

Auxiliary request 2 differs from auxiliary request 1 in that the crosslinking agent (iii) is mandatory.

Claim 1 of auxiliary request 3 is directed to a graphic marking film bonded to a vehicle. The graphic marking film is characterized as in auxiliary request 1 except that the film sheeting material is not limited.

Claim 1 of auxiliary request 4 corresponds to Claim 1 of auxiliary request 1 with the amendment that the following feature has been added at the end of the claim: "wherein the plasticizer-modified acrylic copolymer adhesive permits the application of the graphic marking film at a surface at a temperature as low as -1ºC (30ºF)".

Claim 1 of auxiliary request 5 is directed to the use of a film as graphic marking film for vehicles. The film is characterised as in Claim 1 of auxiliary request 2, ie the crosslinking agent (iii) is mandatory.

For the reasons set out below these newly amended requests were admitted into the proceedings.

IX. In the oral proceedings, the essential points of discussion were:

(a) novelty of the subject-matter according to the main request vis-à-vis D1 or D2;

(b) inventive step of the subject-matter according to auxiliary requests 1, 2, 4 and 5 with regard to a combination of D2 with D6;

(c) lack of clarity of the claims according to auxiliary request 3 and extension of the scope of protection by the claims;

(d) allowability of the limitation of the plasticizer (ii) within the provisions of Article 123(2) EPC.

A final decision on point (d) was not taken because this issue had no influence on the outcome of the proceedings. Discussion of this point in the following is therefore unnecessary.

Furthermore, the need to consider the Opponent's alleged prior public use based on the exhibits "B", "E" and "N" did not arise because, as will be shown below, none of the requests was allowable in view of the prior art represented by D1, D2 and D6 (main request, auxiliary requests 1, 2, 4, 5) or for formal reasons (auxiliary request 3).

X. The arguments of the Appellant/Opponent as regards points (a) to (c) above may be summarised as follows:

Main Request - Novelty (point (a))

A tape with a base sheet and an acrylate copolymer pressure sensitive adhesive system including a dioctyl phthalate (DOP) plasticizer, as set out in Claim 1, was disclosed in D1. According to column 4, lines 63 to 67 the adhesion of the tape to a decorative trim strip was tested. This implied that graphic markings could be made on top of the tape.

D1 was therefore novelty-destroying for the subject-matter of Claim 1.

D2 disclosed pressure sensitive adhesive sheets with a base sheet and a pressure-sensitive acrylate copolymer adhesive composition including an alkylphenoxy poly(ethyleneoxy) ethanol surfactant on one surface of the sheet. The acrylate copolymer contained desirably a polar comonomer in amounts of 5 to 20 wt.% and met the requirements (b)(i)(1) and (2) of Claim 1. The surfactant which was present in amounts as set out in feature (b)(ii) acted as a plasticizer under bond formation conditions. The sheet was inter alia suitable for paper label applications, which implied that the sheet surface could depict information in the form of graphic markings.

Therefore, D2 also anticipated the subject-matter of Claim 1.

Auxiliary Requests 1, 2, 4, 5 - Inventive Step (point (b))

The closest prior art for the subject-matter of these requests was represented by D2.

The film according to Claim 1 of auxiliary request 1 differed from the adhesive sheet described in D2 only by a specific film sheeting material. It was, however, known from D2 itself that synthetic resins were commonly used as film backing material and the specific backing resins as defined in Claim 1 were for instance disclosed in D6, column 3, lines 38 to 41.

Because no technical effect, caused by the specific film sheeting, was shown, the claimed subject-matter lacked an inventive step over a combination of D2 with D6.

Likewise, it was common general knowledge for a skilled person to crosslink acrylate-based pressure sensitive adhesives as required by Claim 1 of auxiliary request 2. This was inter alia indicated in D6, column 1, lines 52 to 56.

Thus, a combination of D2 with D6 also rendered the subject-matter of Claim 1 of auxiliary request 2 obvious.

The additional feature in Claim 1 of auxiliary request 4 that the plasticizer-modified acrylic adhesive permits the application of the claimed film at low surface temperatures was already disclosed in D2. Thus, the same observations made with regard to auxiliary request 1 also applied for the subject matter of auxiliary request 4.

Claim 1 of auxiliary request 5 pertained to the use of the film as graphic marking film for vehicles.

The use of the paper labels according to D2 for adhering them to stainless steel at low temperatures was disclosed in example 1. Therefore, a skilled person starting from D2 was faced with the problem of finding a specific application for the pressure sensitive adhesive sheet. However, adhering a label to a vehicle and modifying the sheeting material in accordance with D6 was a matter of routine for a skilled person.

Auxiliary request 3 - Lack of clarity/Extension of scope (point (c))

Claim 1 of auxiliary request 3, which was directed to a graphic marking film bonded to a vehicle lacked clarity, contrary to Article 84 EPC, because it was not clear whether protection was sought for a film or a vehicle. In the latter case, an extension of the scope of the patent occurred, contrary to Article 123(3) EPC, because an aliud was claimed.

XI. The counter-arguments of the Appellant/Proprietor as to points (a) to (c) were as follows:

Main Request - Novelty (point (a))

The subject-matter according to Claim 1 was novel over D1 and D2 in that these documents did not disclose graphic marking films in the sense of the teaching of the patent.

D1 disclosed an acrylate-based pressure sensitive adhesive with excellent adhesion to plasticized vinyl substrates. Adhesive tapes were prepared for evaluating the adhesion capacity of the PSA to various substrates, inter alia a decorative trim strip. However, D1 contained no disclosure that graphic markings could be made on the tape surface.

D2 was concerned with the field of the paper label industry and all relevant examples were concerned with paper labels. There was no disclosure in D2 that these labels were suitable for outdoor applications such as the provision of vehicles, like trucks or trailers, with graphic markings.

Auxiliary Requests 1, 2, 4, 5 - point (b)

When considering D2 representative of the closest prior art, the subject-matter of Claim 1 of auxiliary request 1 differed from the labels according to D2 in that a specific polymeric film sheeting was used instead of a paper backing material.

The problem to be solved by this distinguishing feature was the avoidance of blistering due to entrapment of air and tenting around the areas of corrugations and rivets, especially on the surface of trucks or trailers. This problem could not be solved by the very stiff and inflexible paper backing material used for the labels according to D2.

There was no information in the prior art that would motivate a skilled person to combine a specific backing material with an acrylate adhesive component containing a specific plasticizer as claimed in order to solve the problem posed.

This situation was not changed when starting from D6 as the closest prior art. Although D6 disclosed an adhesive-backed film composite with a flexible sheeting and an acrylate adhesive component in accordance with Claim 1 for use on the surface of soft side truck coverings, the adhesive did not contain a plasticizer but rather required a heat-sensitive urethane latex as additional adhesive component, which was not foreseen in the PSA system of the claimed graphic marking film.

These arguments also applied to Claim 1 of auxiliary request 4 which was further limited by the feature that the plasticized acrylic copolymer adhesive had to be suitable for low-temperature applications.

It was shown in example 4 of the patent specification that the presence of a crosslinker in the acrylate PSA composition, which was mandatory according to Claim 1 of auxiliary request 2, led to a considerable reduction of film shrinkage without affecting its low temperature application performance. This was not obvious from the prior art.

D6, disclosing the use of adhesive-backed polymeric films for decorating soft side coverings of trucks, was representative of the closest prior art for the use of the film as graphic marking film for vehicles as claimed in Claim 1 of auxiliary request 5.

However, the adhesive composition described in D6 differed from that according to Claim 1 in two essential aspects, namely the absence of a plasticizer and the mandatory presence of a heat-activable urethane latex adhesive.

There was, however, no indication in the prior art, especially D2, which would give an incentive to a skilled person to modify the adhesive system of the films according to D6 by adding a specific plasticizer and removing the urethane latex in order to render the films usable as marking films for vehicles.

Auxiliary Request 3 - point (c)

It was clear from the wording of Claim 1 that protection was sought for a graphic marking film. The objections of the Appellant/Opponent as to lack of clarity were therefore unfounded.

The way of drafting the claim, which was now directed to a film bonded to a specific surface, led to a restriction of the scope which did not violate Article 123(3) EPC.

XII. The Appellant/Patent Proprietor requested that the decision under appeal be set aside and the patent be maintained as granted, alternatively on the basis of one of the auxiliary requests 1 to 5 filed on 14 May 2008.

XIII. The Appellant/Opponent requested that the decision under appeal be set aside and the patent be revoked.

It further requested that the new auxiliary requests be not admitted into the proceedings.