Surgery – Means and methods for collecting body fluids or waste material – Absorbent pad for external or internal application and...
Reexamination Certificate
1998-12-07
2001-05-01
Dawson, Glenn K. (Department: 3761)
Surgery
Means and methods for collecting body fluids or waste material
Absorbent pad for external or internal application and...
C604S367000, C604S358000, C604S385010
Reexamination Certificate
active
06225524
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to absorbent articles, in particular sanitary napkins and panty liners comprising compositions providing odour control benefits.
BACKGROUND OF THE INVENTION
Whilst the primary focus of absorbent articles remains the ability of these articles to absorb and retain fluids, another important area of development in this field is the control of odourous compounds contained within the absorbed fluids or their degradation products. There are a wide range of compounds which may be present in an absorbent article during use which result in the formation of malodourous. These compounds include fatty acids, ammonia, amines, sulphur containing compounds and ketones and aldehydes.
The art is replete with descriptions of various odour controlling agents for use in absorbent articles in order to address the problem of malodour formation. These agents can typically be classified according to the type of odour the agent is intended to combat. Odours may be classified as being acidic, basic or neutral. Acidic odour controlling agents have a pH greater than 7 and typically include inorganic carbonates, bicarbonates, phosphates and sulphates. Basic odour controlling agents have a pH of less than 7 and include compounds such as citric acid, boric acid and maleic acid.
Neutral odour controlling agents have a pH of approximately 7. Examples of these types of compounds include activated carbons, clays, zeolites, silicas and starches. Such neutral odour controlling agents are the most commonly utilised in absorbent articles.
For example EPO 348 978 discloses an absorbent article comprising an odour control system wherein the neutral odour controlling particles are selected from carbon, clays, silicas, zeolites and molecular sieves. EPO 510 619 relates to absorbent article comprising odour control complex including a combination of at least 2 agents selected form a group which includes zeolites and silica gels. Similarly, WO 91/12029, WO 91/11977 and WO 91/12030 disclose the combination of zeolites and absorbent gelling materials.
EPO 282 287 discloses a deodouriser suitable for use in a sanitary napkin which is non black comprising at least one compound selected from metal silicates and metal salts of aluminum containing silicates selected from certain transition metals and group II metals.
WO 81/01643 relates to the removal of nitrogenous irritants present in waste matter in diapers by the use of an inorganic aluminosilicate zeolite ammonium ion exchange material. In addition silica gel may be present to absorb additional water. Carbon is a preferred component of the system
Carbon has been noted in the art as being particularly effective over a broad spectrum of odours. However, it is not favoured due to its black appearance, which is considered unacceptable by consumers. Hence a currently preferred odour control agent is zeolite particularly the so-called intermediate and high ratio zeolites. Although zeolite does not have a negative aesthetic profile, its main drawback is its lack of effective odour control over a broad range of odour types and the expense of such materials.
Consequently, there still exists a need to provide an odour controlling agent or system which has an acceptable aesthetic profile such that it is light coloured and provides effective odour control over a wide range of malodourous compounds and which is not expensive.
It has now been observed that this need may be addressed by the use of the combination of zeolite with silica to effectively combat a wide range of odours which may be present within an absorbent article. Furthermore, the wide range odour control benefits are provided by a dual component system not a tri component system.
An additional advantage of the present invention is that the odour control system comprises components which are all light in colour and thus are not noticeable within the absorbent article and are therefore acceptable from a consumer standpoint.
None of the identified prior art has recognised that this specific combination of absorbent gelling materials and silica provides the above described benefits.
SUMMARY OF THE INVENTION
The present invention relates to an absorbent article comprising a liquid pervious topsheet, a backsheet and an absorbent core intermediate said topsheet and said backsheet, characterised in that said absorbent article comprises an odour control system comprising the combination of silica or a metal silicate excluding transition metals having a molecular weight of 136 or more with absorbent gelling material.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to absorbent disposable articles such as sanitary napkins, baby diapers, incontinence products and panty liners. The absorbent article of the present invention comprise the essential features of a liquid pervious topsheet a backsheet and an absorbent core intermediate the topsheet and the backsheet. The absorbent article further comprises as an essential component an odour control system.
Odour Control System
According to the present invention the absorbent article comprises as an essential feature an odour control system comprising the combination of an absorbent gelling material and silica, which is effective over a wide range of malodours.
Absorbent Gelling Materials
Thus according to the present invention the odour controlling system comprises as an essential component absorbent gelling material. As is well-known from recent commercial practice, absorbent gelling materials (sometimes referred to as “super-sorbers”) are becoming broadly used in absorbent articles. AGM's are materials which have fluid-absorbing properties. Such materials form hydrogels on contact with water (e.g., with urine, blood, and the like). One highly preferred type of hydrogel-forming, absorbent gelling material is based on polyacids, especially polyacrylic acid. Hydrogel-forming polymeric materials of this type are those which, upon contact with fluids (i.e., liquids) such as water or body fluids, imbibe such fluids and thereby form hydrogels. These preferred absorbent gelling materials will generally comprise substantially water-insoluble, slightly cross-linked, partially neutralized, hydrogel-forming polymer materials prepared from polymerizable, unsaturated, acid-containing monomers. In such materials, the polymeric component formed from unsaturated, acid-containing monomers may comprise the entire gelling agent or may be grafted onto other types of polymer moieties such as starch or cellulose. Acrylic acid grafted starch materials are of this latter type. Thus, the preferred absorbent gelling materials include hydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch, polyacrylates, maleic anhydride-based copolymers and combinations thereof. Especially preferred absorbent gelling materials are the polyacrylates and acrylic acid grafted starch.
Whatever the nature of the polymer components of the preferred absorbent gelling materials, such materials will in general be slightly cross-linked. Crosslinking serves to render these preferred hydrogel-forming absorbent materials substantially water-insoluble, and cross-linking also in part determines the gel volume and extractable polymer characteristics of the hydrogels formed therefrom. Suitable cross-linking agents are well known in the art and include, for example, (1) compounds having at least two polymerizable double bonds; (2) compounds having at least one polymerizable double bond and at least one functional group reactive with the acid-containing monomer material; (3) compounds having at least two functional groups reactive with the acid-containing monomer materials; and (4) polyvalent metal compounds which can from ionic cross-linkages. Cross-linking agents of the foregoing types are described in greater detail in Masuda et al; U.S. Pat. No. 4,076,663; Issued Feb. 28, 1978. Preferred cross-linking agents are the di- or polyesters of unsaturated mono-or polycarboxylic acids with polyols, the bisacrylamides and the di-or triallyl amines. Especially pref
Gagliardini Alessandro
Guarracino Mario
Cummings Theodore P.
Dawson Glenn K.
Fitzpatrick Matthew P.
Johnson Kevin C.
Kidwell Michele
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