CASELAW-EPO - reviews of EPO Boards of Appeal decisions

T 1170/19 – Accidental anticipation?

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The patent relates to a foundry additive based on graphite.

Brief outline of the case

The proprietor appealed the decision of the OD to revoke the patent

The MR of the proprietor was rejection of the opposition.

Maintenance in amended form according to AR1 and 2 already filed in opposition was also requested.

Claim 1 as granted reads:  Foundry additive comprising finely milled microcrystalline or amorphous graphite which has an average particle size D50 of less than 100µm

The OD has decided that claim 1 as granted lacked N over D2=WO98/50181 which discloses a foundry additive of 74 µm (Mesh 200).

The OD has decided that claim 1 of AR1=claims 1+2 as granted was lacking N over D3=EP 2 233 226 corresponding to D3a=WO 2009/093621. Some examples of D3 mentioned an average particle diameter of respectively 56 µm, 29 µm and 30 µm.

The OD has decided that claim 2 of AR2 = claims 1+2+4 as granted, lacked IS over D1=DE 32 46 324 as CPA. D1 discloses particles with an average particle diameter of less than 150 µm.

The board held that claim 1 of the MR was lacking N over prior art under Art 54(2), D3a (on the basis of D3), which was not considered as an accidental anticipation.

The same applied to AR1.

AR2 was deemed lacking IS on the basis of D1 as CPA.

The revocation was thus confirmed, even if the grounds were partly different.

Lack of N of the MR=as granted

Relevant for the discussion on N during appeal of the MR is D3a=WO 2009/093621 published in Japanese and D3=EP 2 233 226 corresponding with D3a, but in an official language of the EPO.  D3a is prior art under Art 54(2) but reference is made to D3, prior art under Art 54(3), published after the filing date.

Particle sizes are determined according to D3 by means of laser diffraction. This measurement method is also used according to paragraph [0032] of the patent to determine the particle size D50.

In D3, the claimed average particle diameter was 80 to 3000 µm, cf. claim 8 as originally filed.

Some comparative examples in D3 had average particle diameters of respectively 56 µm, 29 µm and 30 µm.

For the board, even being considered as “negative examples”, some of the particles of D3 fulfil all the features of the foundry additive according to claim 1 as granted.

The proprietor argued that the results of a particle size determination can depend on the measuring method and that the indication of a mean particle size is not necessarily always synonymous with the indication of a particle size D50.

For the board this is irrelevant, since according to D3 the same measuring method is used as in the patent and the indication of the particle size also refers to a D50 value.

Accidental anticipation

The proprietor further argued that D3 constituted an accidental anticipation and was not to be taken into account in the assessment of N.

The board held that, even if D3 does not address the exact same problem in detail as the patent, it does not constitute a disclosure in a remote technical field.

Rather, D3 concerns exactly the same subject matter and generally the same objective as the patent, namely to provide a foundry additive. Thus, D3 does not constitute an accidental disclosure in the sense of established case law.

The board added that, even if one were to assume for the sake of argument that D3 is an accidental anticipation, the teaching of such documents would nevertheless has to be taken into account when assessing N. According to Art 54(2), any prior art must be taken into account for novelty.

For the board, even if the case law on accidental disclosure is dealt with in a subchapter on N, there is no indication in it that such documents should be disregarded.

Rather, case law shows in which cases it may be permissible to establish N. By delimiting a claim against an accidental anticipation under Art 54(2) N can be restored by means of non-disclosed disclaimers, cf. G 1/03.

Neither the EPC nor the case law on accidental disclosure therefore support the proprietor’s argument that accidental disclosure must be disregarded for N.


Some of the examples disclosed in D3 did not fall in the claimed range of D3; they nevertheless disclosed the ranges claimed in the patent.

Those examples in D3 and the corresponding description are in clear opposition with what is actually taught and claimed in D3. This is why the board considered them as “negative examples” in D3.

It can be inferred that the board considered that the “negative” examples in D3 suitable for the purpose dealt with in the present patent.

On the other hand, D3 clearly distinguishes two ranges: above and below 100 µm. Below 100 µm, the particles cannot, according to D3 be used as foundry additive.

D3 might belong to the same technical field as the patent, but D3 makes it clear that particles below 100 µm are not suitable to be used as foundry additives.

The argumentation of the board is therefore not absolutely convincing when one takes into account the non-suitability of the particles according to D3 as foundry additive.

It would have been possible to consider the particles disclosed in D3 as accidental anticipation.   

What do you think?

Further note

It is also interesting to note that the ISR established by the EPO mentioned no less than 10 A documents. Claims 1-10 were left untouched, claims 11-14 deleted so that the grant was direct.

None of the documents used in opposition were mentioned in the ISR. D3a is clearly PA under Art 54(2) and D3 PA under Art 54(3).

It is alas not the first time that the opponent brings forward prior art under Art 54(3).

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