T 0847/20 22-06-2021

Summary of Facts and Submissions

I. The appeal by the patent proprietor lies against the decision of the opposition division posted on 10 February 2020 revoking European patent No. 2 705 073.

II. A notice of opposition had been filed against the patent, requesting the revocation of the patent in its entirety.

III. The contested decision was based on:

- a main request and auxiliary requests 1-34 as filed with letter of 1 March 2019,

- auxiliary requests 1A and 1B filed during oral proceedings.

IV. Claims 1 and 2 of the patentee's main request read as follows:

"1. A macro initiator comprising one or two hydrophobic segments in a molecule, wherein a molecular weight of the hydrophobic segments is 400 to 1500, wherein the hydrophobic segment is a segment made from polysiloxane, and wherein the macro initiator is expressed by formula (a0) or (a1):

FORMULA/TABLE/GRAPHIC

(wherein in (a0) and (a1),

R**(1) is one type of group selected from an alkyl group or an alkoxy group;

R**(2) is one type of group selected from (CH2)n and (CH2)m-O(CH2)n;

m is from 1 to 16; n is from 2 to 5; a is from 4 to 19; b is from 1 to 6, and X is one type of group selected from O, NH, and S)."

"2. A block copolymer comprising one hydrophobic segment and one hydrophilic segment, wherein a molecular weight of the hydrophobic segment is 400 to 1500, wherein the hydrophobic segment is a segment made from polysiloxane, wherein the block copolymer is expressed by formula (b1) or (b2).

Formula:

FORMULA/TABLE/GRAPHIC

(wherein in (b1) and (b2),

R**(1) is one type of group selected from an alkyl group or an alkoxy group;

R**(2) is one type of group selected from (CH2)n and (CH2)m-O(CH2)n;

m and n are independent, ranging from 1 to 16; a is from 4 to 19; b is from 1 to 6, c is from 1 to 10,000, X is one type of group selected from O, NH, and S; and R**(3) and R**(4) represent groups made of monomers with hydrophilicity wherein a monomer is expressed by general formula (n)).

FORMULA/TABLE/GRAPHIC"

The remaining claims of that request are not relevant to the present decision.

V. The following document was inter alia cited in the decision under appeal:

Declaration of Mr. Nakamura (inventor) dated 27 February 2019 (filed with letter of 1 March 2019)

VI. In that decision the opposition division held in summary that:

- The main request did not comply with Article 123(2) EPC;

- Auxiliary requests lA and lB were not admitted into the proceedings;

- Auxiliary requests 1 and 2-34 did not comply with Article 123(2) EPC.

Therefore, the patent was revoked.

VII. The patent proprietor (appellant) appealed the above decision. With the statement setting out the grounds of appeal the appellant requested that the contested decision be set aside and that the case be remitted to the opposition division for further prosecution in respect of the opponent's attacks under Article 100(a) and 100(b) EPC on the basis of the main request (MR) or auxiliary requests 1-42 (AR1-AR42) all filed with the statement of grounds of appeal.

The following table was inserted by the patent proprietor in the statement of grounds to provide concordance with the requests on file before the department of first instance (no request was indicated in the second column for new requests in appeal):

New ID: Appeal|Old ID: Opposition|

MR |MR |

AR1 |- |

AR2 |AR7 |

AR3 |AR1A |

AR4 |AR1B |

AR5 |- |

AR6 |AR5 |

AR7 |- |

AR8 |AR20 |

AR9 |- |

AR10 |- |

AR11 |- |

AR12 |AR1 |

AR13 |AR2 |

AR14 |AR3 |

AR15 |AR4 |

AR16 |AR6 |

AR17 |AR8 |

AR18 |AR9 |

AR19 |AR10 |

AR20 |AR11 |

AR21 |AR12 |

AR22 |AR13 |

AR23 |AR14 |

AR24 |AR15 |

AR25 |AR16 |

AR26 |AR17 |

AR27 |AR18 |

AR28 |AR19 |

AR29 |AR21 |

AR30 |AR22 |

AR31 |AR23 |

AR32 |AR24 |

AR33 |AR25 |

AR34 |AR26 |

AR35 |AR27 |

AR36 |AR28 |

AR37 |AR29 |

AR38 |AR30 |

AR39 |AR31 |

AR40 |AR32 |

AR41 |AR33 |

AR42 |AR34 |

In auxiliary request 1 claims 1 and 2 were amended with respect to the main request by adding the expression "wherein the hydrophobic segment is formed from reaction of a reactive polysiloxane".

In auxiliary request 2 claims 1 and 2 were amended with respect to the main request by adding the expression "wherein the macro initiator is formed by reacting a reactive linear polysiloxane having a functional group on at least one terminus with an azo-type initiator having a carboxy group".

In auxiliary request 3 claims 1 and 2 were amended with respect to the main request in that the hydrophobic segment was defined as being "a segment made from a reactive linear polysiloxane having a functional group selected from a hydroxyl group, and amino group, and a thiol group on at least one terminus, the macro initiator being formed by reacting the reactive linear polysiloxane with an azo-type initiator having a carboxy group".

In auxiliary request 4 claim 1 was deleted and claim 2 was amended with respect to the main request in that the hydrophobic segment was defined as "a polysiloxane segment", the polysiloxane segment was defined as being "a segment made from a reactive linear polysiloxane having a functional group selected from a hydroxyl group, and amino group, and a thiol group on at least one terminus, the reactive linear polysiloxane being reacted with an azo-type initiator having a carboxy group to form a hydrophobic segment containing macroinitiator" and the expression "the hydrophobic segment containing macroinitiator being reacted with at least one hydrophilic monomer to form the block copolymer" was added.

In auxiliary request 5 claims 1 and 2 were amended with respect to the main request in that the hydrophobic segment was defined as being "a segment made from a reactive linear polysiloxane expressed by the formula (p0), (p1) or (p2)", the formula being defined in the claims, and the expression "the macro initiator being formed by reacting the reactive linear polysiloxane with an azo-type initiator having a carboxy group" was added at the end of the claim.

Auxiliary request 6 included amendments indicated by the appellant to be related to an added matter issue with respect to formula (b2), which amendments are not relevant to the present decision.

Auxiliary requests 7-11 included the amendments in auxiliary requests 1-5 respectively together with further amendments which the appellant indicated to be related to an added matter issue with respect to formula (b2), which further amendments are not relevant to the present decision.

Auxiliary request 12-42 included amendments indicated by the appellant to be related to grounds under Article 100(a) and (b) EPC, which amendments are not relevant to the present decision.

VIII. In the rejoinder, the opponent (respondent) requested that the appeal be dismissed. The respondent further requested that the newly filed auxiliary requests 1, 5, 7 and 9-11 as well as re-filed auxiliary requests 3 and 4, which correspond to requests not admitted by the opposition division, not be admitted into the proceedings.

IX. By letter of 28 January 2021, the parties were summoned to oral proceedings to be held on 22 June 2021.

X. By letter of 29 April 2021 the appellant made further submissions and filed new auxiliary requests 5 and 11 to replace the corresponding requests on file.

XI. The board specified issues to be discussed at the oral proceedings in a communication dated 4 May 2021.

XII. With letter of 16 June 2021 the appellant made a further written submission.

XIII. With the explicit agreement of both parties, oral proceedings were held before the Board on 22 June 2021 by video conference.

During oral proceedings, the respondent further requested that auxiliary request 2 be not admitted into the proceedings.

XIV. The appellant's arguments, insofar as relevant to the decision, may be summarised as follows:

(a) Main request

(i) Article 123(2) EPC - Basis for the molecular weight range in claim 1

The molecular weight range of the hydrophobic segment ("400 to 1500") found basis on page 5, penultimate paragraph of the description as filed. Although said passage referred to the reactive linear polysiloxane (RLP), it was clear from the application as a whole that the molecular weight of the hydrophobic segment was identical to the molecular weight of the RLP.

In particular the application as filed provided a synthetic definition of the hydrophobic segment according to which the hydrophobic segment was formed "by reacting a reactive linear polysiloxane ... with an azo-type initiator" (see application as filed, page 5, first paragraph). Thus the skilled person would glean from the specification that (i) there is a direct link between the hydrophobic segment and the polysiloxane, and furthermore that (ii) the nature of the direct link is that RLP is the source of the polysiloxane. It would follow from this that the expression "wherein the hydrophobic segment is a segment made from polysiloxane" (as recited in claims 1-2 of the main request) would be understood by the skilled person to mean that the hydrophobic segment is synonymous with the RLP. This was furthermore confirmed by the examples of the application as filed wherein the molecular weight of the RLP (see example 1) and the molecular weight of the polysiloxane segment (see table 3) were identical. This understanding of the application as filed was corroborated by the declaration of Mr. Nakamura as inventor and skilled person in the present technical field.

Furthermore, the assessment of added matter should be a forward looking holistic assessment, wherein the skilled person, in the light of their common general knowledge and with a mind willing to understand, would start with the application as filed and would examine, looking at the explicit and implicit content of the application as a whole, whether any new technical information has been added in the granted patent. This was not what the opposition division did, rather they undertook a backward looking literal assessment.

Applying the technical and legal framework set out in the preceding paragraphs to the feature in question, the opposition division would have found that the molecular weight feature did not add matter because it flowed naturally from the skilled person's understanding of the chemistry and of the disclosure of the application as filed. In particular, recognising the synthetic definition, the skilled person understood that the molecular weight of the hydrophobic segment was synonymous with the molecular weight of the RLP. Specifically, the explicit recitation of the RLP having a molecular weight of 400 to 1500 implicitly conveyed to the skilled person the information that the hydrophobic segment had a molecular weight of 400 to 1500. In view of this the skilled person was not presented with new technical information as a result of the amendment.

Furthermore, also the preliminary opinion of the Board did not apply the above holistic assessment, rather they undertook a narrow reading of isolated parts of the application. In reply to the question whether the RLP was entirely hydrophobic, the appellant considered that the RLP could include some hydrophilic parts, as long as it was hydrophobic overall. With regard to the leaving group of the RLP, the appellant argued that there would not be any support in the application as filed for a leaving group other than hydrogen. Besides, the skilled person's unimaginative understanding would not extend to higher molecular weight leaving groups. Furthermore, the change of 1 Da between the molecular weight of the RLP and the molecular weight (due to the loss of one hydrogen) would be de minimis in the context of polymer chemistry, where the molecular weights at issue are several orders of magnitude higher. This would be confirmed by the examples of the application as filed wherein the molecular weight of the RLP and the molecular weight of the polysiloxane segment are indicated as identical (see example 1 and table 3). In connection to the question whether the azo-initiator could contribute to the molecular weight of the hydrophobic segment, the appellant took the view that the skilled person would understand from the application as a whole that the hydrophobic segment corresponded to the section derived from the RLP and did not include any part of the azo-type initiator.

(b) Auxiliary requests 1, 5, 7 and 11

(i) Admittance into the proceedings

These requests were responsive to and sought to address the reasoning of the opposition division given in their written decision. It would therefore not have been possible to file the requests earlier. This was all the more relevant given the "change in the subject matter of proceedings" caused by the divergence of the opposition division from their preliminary opinion at oral proceedings. Furthermore, the amendments in the said requests served to explicitly recite the relationship between the hydrophobic segment and the RLP. Accordingly, auxiliary requests 1, 5, 7 and 11 should be admitted into the proceedings.

(c) Auxiliary request 2

(i) Admittance into the proceedings

Auxiliary request 2 corresponded to auxiliary request 7 filed in response to the notice of opposition and dealt with in the contested decision. In addition to original auxiliary request 7, granted claims 2 and 7 were amended as per claim 1. The amendments in said request served to explicitly recite the relationship between the hydrophobic segment and the RLP. On that basis, the request should be admitted into the proceedings.

(ii) Article 123(2) EPC - Basis for the molecular weight range in claim 1

The new feature of claim 1 provided a link between the RLP and the hydrophobic segment. Consequently, it was clear for the skilled person that the parts contributing to the molecular weight of the hydrophobic segment are those which are derived from the RLP. As a result the hydrophobic segment and the RLP were clearly synonymous and the requirements of Article 123(2) EPC were met.

(d) Auxiliary requests 3-4

(i) Admittance into the proceedings

The opposition division did not assess the relevance of auxiliary requests 3-4 (corresponding to auxiliary requests 1A and 1B of the opposition proceedings) on a prima facie basis but undertook a full examination. On that basis the requests were de facto admitted into the proceedings. Furthermore the departure of the opposition division from their preliminary opinion (which was in favour of the main request with respect to added matter) meant that auxiliary requests 3-4 ought to have been admitted on the grounds that the subject of the proceedings has changed.

(ii) Article 123(2) EPC - Basis for the molecular weight range in claim 1

Auxiliary requests 3-4 reflected more closely the language of the description. Claim 1 of said requests specified the identity of the RLP. Furthermore, the claim specified that the RLP reacts with an azo-type initiator having a carboxy group. This would emphasise that the azo-type initiator does not contribute to the molecular weight of the hydrophobic segment. As a result, the molecular weights of the hydrophobic segment and of the RLP were identical and the requirements of Article 123(2) EPC were met.

(e) Auxiliary requests 6, 8-10 and 12-42

(i) Article 123(2) EPC - Basis for the molecular weight range in claim 1

Auxiliary requests 6 and 8-10 were filed to address a separate added matter issue to the above requests, concerning formula (b2) in claim 2. Likewise auxiliary requests 12-42 were filed as part of the appellant's defence to the attacks under Article 100(a) and 100(b) EPC. Nonetheless, the arguments brought forward with respect to the main request and auxiliary requests 2-4 equally applied to auxiliary requests 6, 8-10 and 12-42.

XV. The respondent's arguments, insofar as relevant to the decision, may be summarised as follows:

(a) Main request

(i) Article 123(2) EPC - Basis for the molecular weight range in claim 1

No clear and unambiguous basis was present in the application as filed for a molecular weight range of the hydrophobic segment of "400 and 1500". Said range appeared only once in the original application, namely in the context of the molecular weight of a RLP (see page 5). Contrary to the appellant's view, the "hydrophobic segment" and the RLP were not synonymous in the application as filed. Page 5 of the original description only related to the reactants needed to obtain the hydrophobic-containing macroinitiator (and more specifically to the RLP) while claim 1 of the main request (as well as page 8 of the application as filed) pertained to the structure of the macroinitiator. There was no direct correspondence between the structure of the macroinitiator and the RLP. Even the examples did not provide a basis for the contested amendment since the molecular weight of the hydrophobic segment was not mentioned (but only the molecular weight of a silicone portion). Furthermore, claim 1 of the main request did not reflect that a RLP is used and was not limited to a specific chemistry. Finally, the molecular weights of the RLP and of the hydrophobic segment could not be seen as identical at least in view of the leaving group of the RLP (reducing the molecular weight of the hydrophobic segment by at least 1 Da compared to the molecular weight of the RLP).

(b) Auxiliary requests 1, 5, 7 and 11

(i) Admittance into the proceedings

No explanation or proper justification was given as to why these requests were filed only at the appeal stage. Furthermore, they were not prima facie allowable. In fact, they gave rise to additional objections under Articles 84 and 123(2) EPC. Accordingly, auxiliary requests 1, 5, 7 and 11 should not be admitted into the proceedings.

(c) Auxiliary request 2

(i) Admittance into the proceedings

Auxiliary request 2 was not identical to auxiliary request 7 of the opposition proceedings and was therefore to be considered as a new request filed for the first time with the statement of grounds of appeal. The amendments of claim 2 of auxiliary request 2 raised new issues. Auxiliary request 2 should therefore not be admitted into the proceedings.

(ii) Article 123(2) EPC - Basis for the molecular weight range in claim 1

The added matter objections with regard to the main request were not addressed in auxiliary request 2. The new feature of claim 1 did not remove the deficiency of the main request. In particular the molecular weights of the hydrophobic segment and of the RLP remained different so that the requirements of Article 123(2) EPC were still not met.

(d) Auxiliary requests 3-4

(i) Admittance into the proceedings

The amendments made in auxiliary requests 3-4 were not suitable to overcome the added matter objections. Furthermore the appellant's reference to a change of the subject of the proceedings during the oral proceedings in opposition was not correct. The added matter objections had already been raised earlier during opposition proceedings. Consequently the decision of the opposition division not to admit these requests into the proceedings was correct and should be maintained.

(ii) Article 123(2) EPC - Basis for the molecular weight range in claim 1

The added matter objections with regard to the main request were not addressed in auxiliary requests 3-4. The new features of claim 1 did not remove the deficiency of the main request. In particular the molecular weights of the hydrophobic segment and of the RLP remained different so that the same conclusion applied.

(e) Auxiliary requests 6, 8-10 and 12-42

(i) Article 123(2) EPC - Basis for the molecular weight range in claim 1

The arguments brought forward with respect to the main request and auxiliary requests 2-4 equally applied to auxiliary requests 6, 8-10 and 12-42.

XVI. The appellant requested that the decision under appeal be set aside and that the case be remitted to the opposition division for further prosecution on the basis of the main request or any of auxiliary requests 1-42, whereby the main request and auxiliary requests 1-4, 6-10 and 12-42 were filed with the statement of grounds of appeal and auxiliary requests 5 and 11 were filed with the letter of 29 April 2021.

XVII. The respondent requested that the appeal be dismissed. The respondent further requested that the newly filed auxiliary requests 1, 2, 5, 7 and 9-11 as well as re-filed auxiliary requests 3 and 4, which correspond to requests not admitted by the opposition division, not be admitted into the proceedings. Should the Board come to the conclusion that a request fulfils the requirements of Articles 84 and 123(2) EPC, the respondent requested that the case be remitted to the department of first instance for further prosecution.