T 1164/04 04-04-2006

1. The appeal is admissible.

2. Main request - patent as granted

2.1 Novelty

2.1.1 Using the wording of claim 1 of the patent in suit, D1 discloses a water dispersible and flushable absorbent article (see page 3, last paragraph to page 4, first paragraph), the absorbent article comprising (reference is made to the nappy shown in the embodiment of Fig. 8; see also page 22, lines 17 to 27): a liquid pervious topsheet (cover layer 8), a liquid impervious backsheet (2) disposed beneath said topsheet and an absorbent core (5) disposed between said topsheet and said backsheet, said topsheet (8) comprising a first fibrous assembly having a wet strength resin incorporated therein (see page 22, lines 1 to 3: the resin is a biodegradable thermoplastics such as Biopol®), said backsheet (2) being coated on the topsheet (8) facing surface with a second resinous material (3) wherein said second resinous material is water resistant (see page 19, lines 12 to 16), and said topsheet (8) and said backsheet (2) being joined using a water soluble adhesive in at least an area of peripheral bonding to encapsulate said absorbent core there between (water soluble adhesive 10 and water soluble adhesive strips 11 and 12 are at least in a peripheral portion of the absorbent article, see page 22, lines 20 to 27).

2.1.2 In accordance with the view expressed by the Opposition Division in the decision under appeal, the appellant submitted that the resin Biopol® incorporated in the fibrous assembly of the topsheet was biodegradable but not a temporary wet strength resin, i.e. a resin which underwent rapid decomposition in water.

Although the skilled person generally knows that a "wet strength resin" is a resin that imparts strength to paper when wet, he cannot derive from common general knowledge what specific properties a "temporary wet strength resin" must have. It is noted that in the absence of any evidence in this respect, the appellant´s submission that the skilled person would know what a "temporary wet strength resin" is, must be regarded as an unsubstantiated allegation. Accordingly, as confirmed by the Opposition Division (see page 5, 2nd paragraph, of the decision under appeal), the skilled person would turn to the description for interpreting this expression. However, the Board´s view diverges from that of the Opposition Division as regards the indications given by the description in this respect, for the following reasons. A definition of "temporary wet strength resin" is given only in paragraph [0054] of the patent in suit. There it is stated that "a temporary wet strength resin helps the topsheet 24 maintain its mechanical integrity during use of the sanitary napkin 20 yet does not interfere with the dispersibility of the topsheet when the used sanitary napkin 20 is flushed". In this passage there is no reference to any properties of the resin to rapidly decompose in water. Nor is such reference found in the subsequent passage, which refers to examples of suitable resins. In particular, the passage stating that "when Parez® 631 NC is used at a level between about 0.5% and about 1.0% in the wet laid apertured tissue, the topsheet 24 has a satisfactory balance of mechanical integrity during use and dispersibility during disposal" makes clear that the quantity of resin, and not only its nature, plays a role in conferring a temporary wet strength to the topsheet. It remains to examine what properties of the resin are implied by the statement that it does not "interfere with the dispersibility of the topsheet when the used sanitary napkin is flushed". In this respect, the appellant specifically referred to par. [0047] of the patent in suit, according to which "the coated webs [...] rapidly lose mechanical integrity and dissociate into fragments on immersion in water". Having regard to the additional disclosure, in the same paragraph, of the backsheet dispersing into fragments under "the mild agitation conditions encountered when a conventional toilet is flushed", and to the disclosure in the above-mentioned paragraph [0054] referring to the dispersibility of the topsheet when flushed, it is clear that "dispersibility" implies the loss of mechanical integrity and dissociation into fragments of the fibrous assembly when flushed. However, there is no disclosure of the number and dimensions of fragments. Furthermore, the patent in suit discloses (see par. [0047] and [83]) that the backsheet and the topsheet behave substantially the same as a sample of a commercially available Charmin® toilet tissue, in that they disperse into smaller particles (page 13, lines 46,47). Since the fibrous assembly loses mechanical integrity when wet, the topsheet may dissociate into fragments due to the mechanical action of water agitation. In order not to interfere with dispersibility, the resin present in the fibrous assembly must therefore be such to allow the topsheet to dissociate into fragments under the mechanical action of water agitation. For this to happen, it is not necessary that the resin decomposes when immersed in water. It is sufficient that the resin´s presence (in particular its quantity, distribution, or strength, etc.) is such that it does not resist fragmentation of the fibrous assembly on flushing. Therefore, the expression "temporary wet strength resin" can only be understood in the light of the description of the patent in suit as referring to a resin that imparts strength to a fibrous assembly when wet but which at the same time allows the fibrous assembly to disperse when flushed.

Document D1 clearly discloses that the topsheet (cover layer 8) must be capable of disintegration or degradability, and dispersion by the action of the water flow in the lavatory (see page 15, lines 31 to 3 and page 23, lines 27 to 30). Accordingly, the Biopol® resin can only be such as to allow the fibrous assembly of the topsheet to disperse when flushed. It is, therefore, a temporary wet strength resin within the meaning of the patent in suit.

In this respect it is noted that, since dispersion does not necessarily result from the decomposition of the resin, the fact that the Biopol® resin is biodegradable (i.e. that it decomposes after a relatively long period of time) does not exclude that it allows the fibrous assembly to disperse when flushed.

2.1.3 In the example of Figs. 7 and 8 of D1, the outer layer (2), which corresponds to the backsheet in accordance with the patent in suit, is made of a film of water soluble plastics material (see page 19, lines 11 to 12 in combination with page 22, lines 16 to 27). In the introductory portion of the description, D1 discloses that the outer layer can be made of any suitable material, for instance tissue, provided it loses its integrity when disposed of in a water flushing system (page 5, lines 24 to 30). This general teaching applies to the composite material consisting of a layer of soluble material and a liquid impervious barrier only (see page 5, lines 7 to 10). There is however no clear and unambiguous teaching in D1 that an outer layer made of tissue could replace the film of water soluble plastics material in the absorbent article specifically disclosed in Figs. 7 and 8, which comprises a plurality of layers, in particular an absorbent layer, and in which the solubility of the outer layer (2) in water is described as playing a role in the process of dispersion of the absorbent article as a whole (see page 23, last paragraph).

Therefore, D1 does not disclose the feature of claim 1 of the patent in suit according to which the backsheet comprises a second fibrous assembly having a temporary wet strength resin incorporated therein. In this respect it is additionally noted that the disclosure in D1 of paper such as paper for bags or tissue used for disposable handkerchiefs, table napkins and toilet tissue (page 5, last paragraph) cannot be regarded as an unambiguous disclosure of a fibrous assembly with a wet strength resin: although the use of a wet strength resin is well known and very diffused in these products, there is no evidence that these products only exist with a resin incorporated therein.

Therefore, the subject-matter of claim 1 is novel over D1.

2.2 Inventive step

2.2.1 The provision of a backsheet comprising a fibrous assembly, rather than a layer of plastics material, in the nappy of Fig. 8 of D1, has as a result an alternative construction of the backsheet which is still dispersible when disposed of by flushing (see page 5 of D1, lines 29, 30) but has improved softness.

Accordingly, the objective technical problem solved can be seen in providing an alternative construction of the backsheet which has improved softness.

2.3 The skilled person would consider the posing of this problem since the backsheet of a nappy comes into contact with the skin of the wearer (partially, in the crotch area). In studying document D1 the skilled person would find on page 5, last paragraph, the indication that the layer of soluble material for the composite material could consist of a layer of tissue used for disposable handkerchiefs, table napkins and toilet tissue, rather than a layer of plastics material. Knowing that a layer of tissue is generally softer than a layer of plastics, the skilled person would regard it as obvious to replace the outer layer (2) of plastics material in the nappy of D1 with a layer of tissue in order to solve the above-mentioned problem. In doing this, the skilled person would readily recognize that the tissue must be of the kind having a wet strength. Indeed, humid conditions are often present in use, and D1 discloses (see page 6, lines 11 to 15) that the outer layer must have strength and handling capability such that it does not tear easily and remains undamaged in normal use. Therefore, the skilled person would obviously consider the use of a generally known tissue having a wet strength resin incorporated therein. Since in accordance with the teaching of D1 (page 5, lines 28 to 30) such tissue must disintegrate and disperse when disposed of by flushing, the skilled person would only consider the use of resins which temporarily provide a wet strength, i.e. temporary wet strength resins. Therefore, the skilled person would arrive in an obvious manner to the subject-matter of claim 1.

2.4 Therefore, the appellant´s main request is not allowable for lack of inventive step (Articles 52(1), 56 EPC) of the subject-matter of claim 1.

3. First auxiliary request

3.1 Claim 1 of the first auxiliary request differs from claim 1 as granted in that it defines that each of the first and second fibrous assemblies is a wet laid tissue.

Although the application as filed discloses that the second fibrous assembly may be a wet laid tissue (see in particular original claim 1), there is no clear and unambiguous disclosure of the first fibrous assembly being, generally, a wet laid tissue. Indeed, the application as filed consistently refers, in connection with the first fibrous assembly, to a wet laid tissue in combination with the feature that the tissue is apertured (see original claim 1), or with the feature that the tissue is provided with fibrils (see original claim 14) or sufficient inherent porosity (see page 21, lines 1 to 25).

The appellant referred to paragraph [0051] of the patent in suit, according to which the topsheet may be manufactured from a wide range of materials such as air laid, wet laid, or carded nonwoven materials. However, this general reference to air laid (nonwoven) materials cannot be regarded as a specific disclosure of wet laid tissues.

3.2 Therefore, since the first fibrous assembly is disclosed in the application as filed as being a wet laid tissue only in combination with other features which are not present in claim 1, the amendments made constitute a generalization of the originally disclosed technical information and thereby introduce subject-matter extending beyond the content of the application as filed, contrary to the requirements of Article 123(2) EPC. As a consequence, the appellant´s first auxiliary request cannot be allowed.

4. Second auxiliary request

4.1 Claim 1 of the second auxiliary corresponds to claim 1 of the first auxiliary request with the only difference that the first fibrous assembly is defined to be a wet laid nonwoven rather than a wet laid tissue, which feature finds its basis in the passage on page 17, lines 9 to 17 of the application as filed, which corresponds to paragraph [0051] of the patent as granted. Since claim 1 is amended by way of introduction of additional features, the amendments made restrict the scope of protection.

Claims 2 to 7 are identical to claims 2 to 7 of the patent as granted.

Accordingly, the amendments made to the claims do not give rise to objections under Article 123(2) and (3) EPC.

4.2 However, the appellant has created a new set of facts by introducing in claim 1 features taken from the description of the patent in suit. Since this was requested by the appellant and the respondent did not object, and in order to give the parties the opportunity to prosecute their rights at two levels of jurisdiction, the Board makes use of its powers under Article 111(1) EPC to remit the case to the first instance for further prosecution on the basis of the claims in accordance with the second auxiliary request.