A sweat-absorbent sheet includes a first surface layer, a second surface layer lying on the opposite side of the first surface layer and an intermediate layer sandwiched between these two layers. Each of the first and second surface layers comprises a mixture layer of first and second hydrophobic fibers made of thermoplastic synthetic resin as main constituent and first and second hydrophilic fibers. The intermediate layer comprises third hydrophilic fibers extending into at least one of the first and second hydrophobic fibers. The first and second hydrophobic fibers are bonded to the crimped to hydrophobic composite fibers mixed in the respective layers. The first, second and third hydrophilic fibers are impregnated with antibacterial or bactericidal medicinal ingredient and such medicinal ingredient is left behind on these hydrophilic fibers after these hydrophilic fibers have been dried.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view of sweat-absorbent sheet;
FIG. 2 is a partially cutaway plan view of disposable diaper; and
FIG. 3 is a diagram illustrating a process for making sweat-absorbent sheet.
Claims
1. A sweat-absorbent sheet including hydrophilic fibers which comprises:
said sweat-absorbent sheet having a first surface layer and a second surface layer lying on an opposite side of said first surface layer;each of said first and second surface layers comprising a mixture layer of said hydrophobic fibers as a main constituent made of thermoplastic synthetic resin and said hydrophilic fibers;said first and second surface layers sandwiching therebetween an intermediate layer formed by said hydrophilic fibers, into which said hydrophobic fibers constituting at least one of said first and second surface layers extends;said hydrophobic fibers in said first and second surface layers being welded to crimped hydrophobic composite fibers mixed in said first surface layer, said second surface layer and said intermediate layer; andsaid hydrophilic fibers being impregnated with medicinal ingredient and left behind on said hydrophilic fibers after said hydrophilic fibers have been dried.
2. The sweat-absorbent sheet defined by claim 1, wherein said hydrophilic fibers are fibers selected from the group consisting of rayon, cotton and pulp fibers.
3. The sweat-absorbent sheet defined by claim 2, wherein said rayon fibers are used to form said first surface layer and said second surface layer while said pulp fibers are used to form said intermediate layer.
4. The sweat-absorbent sheet defined by claim 1, wherein, as the medicinal ingredient, one or more quaternary ammonium salts may be selected from the group consisting of alkylpyridinium salt, alkyltrimethylammonium salt, alkylbenzylmethylammonium salt (benzalkonium chloride), dialkyldimethylammonium salt and benzethonium chloride.
5. The sweat-absorbent sheet defined by claim 1, wherein said sweat-absorbent sheet constitutes at least a part of the surface of a disposable wearing article destined to come in contact with a user's skin.
6. The sweat-absorbent sheet defined by claim 5, wherein said disposable wearing article is a disposable diaper and said sweat-absorbent sheet is attached to an inner surface of said disposable diaper in its rear waist region.
7. A process for making the sweat-absorbent sheet defined by claim 1, said process comprises the steps of:
a. feeding a first web in a machine direction, said first web having a basis weight in a range of 7 to 20 g/m2 and comprising first hydrophobic fibers made of thermoplastic synthetic resin constituting 60 to 80% by weight of said first web and first hydrophilic fibers selected from the group consisting of rayon, cotton and pulp fibers constituting 40 to 20% by weight of said first web;b. feeding a second web in said machine direction and placing this second web on said first web, said second web having a basis weight in a range of 7 to 20 g/m2 and comprising first hydrophilic fibers selected from the group consisting of rayon, cotton and pulp fibers;c. feeding a third web in said machine direction and placing this third web on said second web, said third web having a basis weight in a range of 5 to 12 g/m2 and comprising sheath/core type hydrophobic composite fibers consisting of polyethylene as the sheath and thermoplastic synthetic resin having a melting temperature higher than that of polyethylene as the core;d. feeding a fourth web in said machine direction and placing this fourth web on said third web so as to obtain a first composite web comprising said first, second, third and fourth webs placed one on another, said fourth web having a basis weight in a range of 5 to 12 g/m2 and comprising a mixture of second hydrophobic fibers made of thermoplastic synthetic resin constituting 60 to 80% by weight of said fourth web and third hydrophilic fibers selected from the group consisting of rayon, cotton and pulp fibers constituting 40 to 20% by weight of said fourth web;e. subjecting said first composite web to treatment with columnar water jet of 10 to 100 kg/cm2 targeting said first web or said fourth web to entangle component fibers of said first composite web together and thereby to obtain a second composite web;f. drying said second composite web;g. heating said second composite web up to a temperature at which polyethylene in said hydrophobic composite fibers are molten and welding said hydrophobic composite fibers to fibers entangled with said hydrophobic composite fibers;h. immersing said third composite web in aqueous solution of antibacterial or bactericidal medicinal ingredient to obtain a fourth composite web; andi. drying said fourth composite web impregnated with said aqueous solution to obtain said sweat-absorbent sheet.
8. The process defined by claim 7 wherein web having a basis weight in a range of 5 to 12 g/m2 and comprising fourth hydrophilic fibers selected from the group consisting of rayon, cotton and pulp fibers constituting 0 to 50% by weight of this web and said composite fibers constituting 100 to 50% by weight of this web is used as said third web.
9. The process defined by claim 7 wherein one or more quaternary ammonium salts selected from the group consisting of alkylpyridinium salt, alkyltrimethylammonium salt, alkylbenzylmethylammonium salt, dialkyldimethylammonium salt and benzethonium chloride is or are used as said medicinal ingredient.
Patent Application
20070149933
