CASELAW-EPO - reviews of EPO Boards of Appeal decisions

T 1111/21 – A board not sticking to the letter of Art 12(4) and 13(2) RPBA

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The patent relates to a method for manufacturing a ZnAlMg coated sheet comprising the application of an acid solution and a corresponding sheet.

Brief outline of the procedure

The opposition was revoked and the opponent appealed.

The board held that that claim 1 as granted and claim 1 of AR 2 lacked IS over D3+D16. D3 related to ZnAIMg and was disclosed proceedings of a conference. D16 represented common general knowledge.

Claim 1 of AR 1 and 3 lacked IS over D3+D25. D25 was disclosing the proceedings of a conference.

The patent was thus revoked.

The opponent’s point of view

The objection based on D3+D6 should be admitted in the procedure.

The only distinguishing feature in relation to D3 is feature [1.5]. The failure tests reported in D3 show that adhesive failure occurred for a ZnAlMg coating. It follows from general knowledge that adhesive failure can be reduced by acid pre-treatment. The choice of the claimed pH range is also arbitrary and has no technical effect demonstrated in the patent. Moreover, this range is common in the state of the art.

The objection based on D3+D25 should be admitted in the procedure.

This objection is a reaction to the argument concerning the effect of selecting the range of duration of the acid treatment, put forward for the first time with proprietor’s reply to the  grounds of appeal.

D25 proposes the same solution, acid pre-treatment, to improve the adhesion of an adhesive to a ZnAlMg coating, as suggested by general knowledge. In addition, it is shown that only the very thin oxide layer needs to be removed by acid, resulting in short treatment times. The range of treatment times chosen is also arbitrary because, as confirmed by the proprietor, different results are to be expected for each combination of materials within the scope of claim 1.

The proprietor’s point of view

The proprietor requested not to admit in the procedure the objections based on D3+D16 as being late filed.

Moreover, the skilled person would have chosen the GI coating also disclosed in D3. Furthermore, D16 does not address ZnAlMg coatings and discloses different pre-treatment alternatives. The choice of pH range is also not suggested by general knowledge. Claim 1 is thus inventive over D3+D16.

The proprietor requested not to admit in the procedure the objections based on D3+D25 as being late filed.

Moreover, the patent shows in Table 1 the surprising effect that short acid treatment times improve adhesion properties. This is not apparent in D25. In addition, D25 uses a different coating composition and adhesive. Therefore, the results of D25 are not applicable to the material combination disclosed in D3.

The board’s decision

The board held that D3 discloses three types of zinc coating obtained on both surfaces of a steel substrate by dipping in a hot bath:

  • a ‘GI’ ‘galavanised’ type coating, hot zinc bath
  • a ‘GA’ ‘galvanealed’ coating, hot zinc bath; the coating being annealed after galvanising
  • an ‘MZ’ ‘hot dip ZnAlMg coating’, a hot bath of zinc with aluminium and magnesium

D3 sets out the different properties of zinc coatings obtained by these different processes.

As contended by both parties, D3 discloses all of the features of claims 1 and 15 in combination, with the exception of feature [1.5].

Admittance of the objection based on D3+D16

The opponent claimed that it is common general knowledge to pre-treat metal surfaces with acid to improve adhesive properties with epoxy adhesives.

This general knowledge had already been presented in the statement of grounds for opposition and had also been raised in an objection for lack of inventive step in relation to D3.

Thus, the objection was raised from the outset of the opposition proceedings and was upheld in appeal. The only difference is that the common general knowledge is proved by different documents; in the contested decision, D10 and D24; in the grounds of appeal, D16.

Although the reference to document D16 as evidence of general knowledge constitutes an amendment under Art 12(4) RPBA, it does not entail a fundamental change in the objection and does not undermine the principle of procedural economy.

Consequently, the board admitted the objection by exercising its discretion in accordance with Article 12(4) RPBA.

Admittance of the objection based on D3+D25

AR 1 and 3 had already been submitted during opposition proceedings. However, it was only in its response to the communication under Art 15 (1) RPBA that the proprietor first mentioned the effect of the choice of acid treatment time and the technical problem solved with this additional feature.

The opponent responded to this late argument by putting forward additional arguments concerning the objection for lack of IS raised in the statement of grounds of appeal, having regard to document D3 in combination with document D25.

There is no information on the duration of acid treatment in document D16. However, there is at least one indirect indication on this subject in document D25.

The bord thus held that exceptional circumstances existed, so that the objection based on D3+D25 was admitted under Art 13(2) RPBA.

The opponent reacted to the reasons given belatedly by the proprietor concerning the effect resulting from feature [1.5′].

Apart from this, there was no substantial change to the argument developed in the appeal.


Change of document representing CGK

In the appealed decision, D10 and D24; were representing CGK. In the grounds of appeal, D16 was representing CGK. In spite of the change of CPA represented an amendment, the board admitted the new objection as it did not entail a fundamental change in the objection and did not undermine the principle of procedural economy.

Objection based on D3+D25

It was only in reaction to the communication under Art 15(1) RPBA that the proprietor came with a new argument. The board could have decided not to take it into account under Art 13(2) RPBA. Not only the argument was admitted, but also the reaction of the opponent to this late submission. The reaction could also not have been taken into account under Art 13(2).


Contrary to certain boards, which have very set views and stick to the letter of  Art 12(4) and/or 13(2) RPBA and therewith stifle in the bud any discussion on those amended or late filed submissions, the present board did a good job and revoked a patent which had manifestly no raison d’être.

This is worth being noted.

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