T 0355/07 28-11-2008

I. The firm Andritz Küsters GmbH & Co. KG (henceforth appellant), alleged successor in title to the original opponent Eduard Küsters Maschinenfabrik GmbH & Co. KG as from 11 May 2006, lodged an appeal on 26 February 2007 against the decision of the Opposition Division posted on 3 January 2007 rejecting the opposition against European patent No. 1 105 570, based on Article 100(a) EPC (lack of novelty, Article 54 EPC, lack of inventive step, Article 56 EPC). A statement setting out the grounds for appeal was filed on 28 April 2007. The appellant changed its name into Andritz Küsters GmbH as from 27 August 2007.

II. Oral proceedings were held before the Board of Appeal on 28 November 2008.

III. The appellant requested that the decision under appeal be set aside and that the patent in suit be revoked.

The respondent (patent proprietor) requested:

(i) as a main request, that the appeal be rejected as inadmissible; or

(ii) as first auxiliary request, that the appeal be dismissed as not allowable; or

(iii) as second to eighth auxiliary request, that the decision under appeal be set aside and the patent in suit be maintained on the basis of the sets of claims filed as second to eighth auxiliary request, respectively, on 25 September 2007.

As a further auxiliary measure, the respondent requested to amend the fourth to eighth auxiliary requests by cancelling the amendment (underlined) in "the paper manufactured is SC paper of at least SC-A, SC-B or SC-C paper grade".

IV. The following documents were inter alia referred to in the appeal proceedings:

D2 DE 298 13 663 U1

D4 Calendering of a moistened woodfree uncoated paper, Granberg, A. et al., Nordic Pulp and Paper Research Journal no. 3/1996, pages 132 to 136, 140.

D6 The Role of Nip Temperature and Surface Moisture in the Calendering and Supercalendering Processes, Jackson, M. and Gavelin, G., Svensk Papperstidning 1966, No. 5, pages 131 to 138.

D13 DE 43 01 023 C2

D15 Hard-nip and soft-nip calendering of uncoated groundwood papers, Crotogino, R. and Gratton, M., Pulp & Paper Canada 88:12, 1987, pages 208 to 216.

D17 US-A 5,378,497

V. Claim 1 of the patent as granted (first auxiliary request) reads as follows (labelling of the features by the letters a) through g), j) and k) by the Board):

a) "1. Method for manufacturing calendered paper, in which paper (w) is calendered after drying, wherein the method comprises the following stages:

b) - drying (d) of the paper down to a moisture of under 7% lower than the target moisture of calendering,

c) - wetting (1) of the paper after drying to the target moisture of calendering of over 7,5%, and

d) - multi-nip calendering of the paper in the target moisture when the paper runs via wetting to a multi-nip calender (c)

e1) - at least one of the surface layers of the paper is wetted in the wetting by metering moistening water in such a way that the moistening water is absorbed in the surface layer (W1, W2) of the paper

e2) while the central layer remains substantially in the moisture to which the paper was dried,

characterized in that

f) - the paper manufactured is SC paper grade,

g) - from the paper wetted at least on one of its sides, gradient SC paper is manufactured by means of gradient multi-nip calendering, having over 4 nips and being of the type where successive nips are formed between rolls superimposed in a stack of calender rolls including rolls with metal and polymer surfaces,

j1) by restricting the paper-moulding effect of the multi-nip calender to the wetted surface layer (W1, W2) in such a way that the central layer of the paper is elastically restored substantially in its original state,

j2) and a density difference in the thickness direction is attained in the SC paper while the central layer remains in a density lower than that of the surface layer (W1, W2),

k) - the obtained gradient SC paper is reeled (r)."

VI. The arguments of the appellant, in writing and during the oral proceedings, can be summarized as follows:

Admissibility of the appeal

The findings in the decision T 163/05 of Board of Appeal 3.2.07 dated 8 April 2008, wherein it was held that the final appellant in that case, Andritz Küsters GmbH, resulting from transfers, changes of name and conversions during the appeal proceedings, was the successor in title to the original opponent in that case, Eduard Küsters Maschinenfabrik GmbH & Co. KG (see point 1 of the Reasons) applied to the present case. The appeal was thus admissible.

German utility model (document D2)

Document D2 was a specification of a German utility model registered on 26 November 1998. German utility models were considered publicly available as of their date of entry in the Register so that document D2 represented prior art in terms of Article 54(2) EPC.

Inventive step

Document D2 represented the closest prior art. In the decision under appeal the Opposition Division held that only two features of claim 1 as granted (cf. features e2 and j2 of claim 1 of the auxiliary request) were not known from document D2. However, document D2 referred on page 5, line 27, to document D13. Document D13 taught (see column 2, lines 51 to 65, and column 10, lines 1 to 13) that the web was advantageously moistened just before it entered the calender nip 4, so that the moisture did not have time to enter the inner layer of the web when it was calendered, cf. features e2 and j2. The person skilled in the art, starting from the method for manufacturing calendered paper known from document D2, seeking to simplify the known method, would dispense with the first wetting step proposed by document D2, since the second wetting step and the subsequent multi-nip calendering ("gradient multi-nip calendering") alone improved the paper surface quality (gloss and smoothness) as taught by document D13, and he or she would thus arrive at the subject-matter of claim 1 of the auxiliary request without exercising inventive skills. The first wetting step merely served to homogenously wetting the web immediately after drying to the hygroscopic equilibrium value of the finished paper in ambient conditions during storage. The teaching of document D13, namely that during moisture gradient calendering the central layer remained substantially in the moisture to which the paper was dried, was also known from document D4 (see eg Table 1 on page 133, left column, whereby the moisture content was 3,7% in the as-received state) and D15 (see page 215, left column, lines 7 to 12). According to document D6 the paper had to be dried down to below 5% moisture, since the plasticity of the paper increased considerably at moisture contents in the range of from 8 to 12%, cf. page 138, right column, lines 9 to 13, and page 132, right column, lines 1 to 5. The purpose of step b) of the method according to claim 1 of the auxiliary request, viz. drying (d) of the paper down to a moisture of under 7% lower than the target moisture of calendering, was very similar to the purpose of the first wetting step in the method known from document D2, namely to give the central layer of the web a moisture content that was compatible with the hygroscopic equilibrium value of the paper in ambient conditions during storage. The person skilled in the art knew from document D17 that a paper web having about 3 to 20% moisture at the center of the web could be moisture gradient calendered. It followed that a combination of document D2 with either document D4 (plus document D15), document D6, or document D17 would also lead the person skilled in the art to the claimed invention.

VII. The respondent's arguments, in writing and during the oral proceedings, can be summarized as follows:

Admissibility of the appeal

The appellant could not be recognized as the successor in title to the original opponent, Eduard Küsters Maschinenfabrik GmbH & Co. KG, because the excerpt of the commercial register HRA 5348, Amtsgericht Krefeld, merely mentioned Eduard Küsters Maschinenfabrik GmbH & Co. KG as "Kommanditist" (silent or sleeping partner) of Küsters Technologie GmbH & Co. KG. In the present case the alleged transfer took place during the opposition proceedings, whereas in the case considered in the decision T 163/05 (loc. cit.) the alleged transfer took place during the appeal proceedings. Moreover, case T 163/05 concerned an opposition to a different patent. No evidence was filed that the partial businesses "Non-woven" and "Papier" were actually transferred from Eduard Küsters Maschinenfabrik GmbH & Co. KG via Jagenberg AG to the appellant, now Andritz Küsters GmbH, and no evidence was filed that the opponent status in the present case belonged to these partial businesses. The appeal filed on behalf of the appellant should therefore be rejected as inadmissible.

German utility model (document D2)

The German utility model was registered on 26 November 1998, just one day prior to the validly claimed priority date of the patent in suit. The date of registration was the date on which a list was laid open for inspection at the branch office of the German Patent and Trademark Office (DPMA) at Zweibrückenstraße 12 in Munich. It was practically impossible for a member of the public to get knowledge of the content of document D2 on said day, because (i) the list contained several hundred entries, (ii) the list merely indicated the IPC class and the DPMA file number of German utility models, and (iii) the files itself could only be inspected upon request at another branch office of the DPMA at Cincinattistr. 64 in Munich. It was not proved that a member of the public actually inspected the file corresponding to document D2 on that very day. Document D2 was not therefore state of the art for the patent in suit.

Inventive step

Document D2 was completely silent about the manufacturing of gradient paper according to feature g) of claim 1 of the auxiliary request. It was also silent about any reel up (cf. feature k), and silent about the overall moisture of the web before entering the calender nip (the range of 12 to 25% mentioned on page 12, lines 30 and 31 related only to a surface layer of the web). The subject-matter of claim 1 of the auxiliary request differed from the method for on-line manufacturing of calendered paper of SC-A paper grade known from document D2 in the features e2, g, j1, j2 and k. It was the object of the invention to provide an integrated manufacturing method for manufacturing gradient SC paper comprising low density, greater thickness and higher stiffness at the same surface quality. This object was achieved by the method for manufacturing calendered paper comprising the features of claim 1 of the auxiliary request. In particular, the web was wetted so that the central layer maintained the dryness or moisture which was produced in the drying step and water was absorbed in the surface layer(s) of the web only. Accordingly, the surface layer(s) were permanently compressed providing the required surface quality, whereas the dry central layer was elastically compressed and restored in its original state. The method known from document D2 required that the web was moistened completely by means of the steam moistener 7 in a first wetting step. The second wetting step performed by steam moisteners 19, 19' was not appropriate for significantly increasing the overall moisture content of the web (as explained in eg document D13, column 3, lines 24 to 30), its purpose was merely to establish a temperature gradient, see document D2, page 12, lines 8 to 20. It was therefore not obvious to the person skilled in the art starting from document D2 to omit the wetting device 7. Considering a combination of document D2 with any of the documents D4 (+ document D15) or D6 could not lead to a different conclusion. Document D4 was a report about test calendering of wood free uncoated paper in a pilot equipment (see page 132, left column, first paragraph of the Summary). The aim was to investigate how gradient moistening (water, not steam) just before the single calender nip operated at different speeds affected the paper properties, whereby homogenously wetted paper and unwetted paper having a moisture content of 10,5% and 3,7%, respectively, served as references (see table 1 on page 133, left column). Documents D6 was a report about investigations about the effect of web moisture content and web temperature during calendering on the physical, optical and printability properties of paper, see page 131, first paragraph. Document D6 did not concern SC paper, and the tests were carried out on a single nip laboratory calender, see Figure 1 on page 132, left column. Moreover, the passage on page 138, right column, lines 9 to 13, of document D6 cited by the appellant did not give any hint regarding the overall moisture after wetting.