Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Nonwoven fabric – Including an additional nonwoven fabric
Reexamination Certificate
1999-03-04
2001-02-13
Edwards, N. (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Nonwoven fabric
Including an additional nonwoven fabric
C442S364000, C442S361000
Reexamination Certificate
active
06187699
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a laminated nonwoven fabric and to a method of manufacturing the same. More specifically, the present invention relates to a nonwoven fabric of multi-layer structure comprising a composite spun bonded nonwoven fabric laminated on a composite meltblown extra-fine-fiber nonwoven fabric. The laminated nonwoven fabric is preferably used as surface material for absorptive products such as disposable diapers and sanitary napkins.
BACKGROUND ART
Spun bonded nonwoven fabrics have been used as surface material for absorptive products such as disposable diapers, because they are hardly napped or fluffed and have excellent fiber detachment resistance. However, continuous fibers (filaments or long fibers) that form the spun bonded nonwoven fabrics are difficult to make finer. Thus, the spun bonded nonwoven fabrics are difficult to provide a soft texture like that of meltblown nonwoven fabrics composed of extra-fine fibers. In addition, the spun bonded nonwoven fabrics have another drawback in that when their constituent fibers are made finer, more single fibers are cut short and thus more fibers of a larger fineness are mixed, leading to deterioration in texture.
Laid-open Japanese Patent Publication No. Sho 54-134177 discloses a meltblown nonwoven fabric composed of extra-fine polypropylene fibers, and Laid-open Japanese Patent Publication Nos. Sho 62-299501 and Hei 3-75056 disclose a disposable diaper employing a meltblown nonwoven fabric as its surface material. Meltblown nonwoven fabrics are advantageous in that they provide a soft texture due to their small fiber diameter. However, meltblown nonwoven fabrics have inherent drawbacks, including weak nonwoven fabric strength, generation of naps or fluffs, and tendency of permitting fiber detachment. In addition, they have such drawbacks that polymer particles are likely to be formed at the time of spinning, thus imparting the fabrics rough hand feeling, and the fabrics irritate the skin, making it unsuitable for disposable diapers for newborn babies. In order to improve the strength of meltblown nonwoven fabrics and to prevent fiber detachment, the meltblown nonwoven fabrics are being subjected to pressing with heated calender rolls or heated emboss rolls. However, the heat pressing must be performed under severe temperature and pressure conditions, leading to increase in the apparent density of the nonwoven fabrics and deterioration in the texture thereof.
Japanese Patent Publication No. Sho 60-11148 and Laid-open Japanese Patent Publication Nos. Hei 2-112458 and Hei 2-234967 disclose a laminated nonwoven fabric wherein a spun bonded nonwoven fabric is laminated on a meltblown nonwoven fabric, and the two layers are thermally fused to each other by the use of heated calender rolls, heated emboss rolls, or the likes. The resultant nonwoven fabric has improved strength as compared with that of conventional single-layer nonwoven fabrics. However, the nonwoven fabric has drawbacks, including unsatisfactory fusion between layers, poor fiber detachment resistance, and insufficient delamination strength, since regular fibers are used as continuous fibers that compose the spun bonded nonwoven fabric. In addition, in order to press the spun bonded nonwoven fabrics with heated emboss rolls, severe heating and pressing conditions are required, leading to drawbacks such as high apparent density and deterioration in texture.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a laminated nonwoven fabric which has a high strength, soft texture, and excellent fiber detachment resistance, is not rough to the touch, and causes no irritation to the skin. Another object of the present invention is to provide a method of manufacturing the laminated nonwoven fabric.
The present invention for achieving the above objects is summarized as follows:
(1) A laminated nonwoven fabric of multi-layer structure comprising a composite spun bonded nonwoven fabric laminated on a composite meltblown extra-fine-fiber nonwoven fabric having an average fiber diameter of 10 &mgr;m or less; wherein
the composite spun bonded nonwoven fabric comprises a composite continuous fiber composed of a low melting point resin and a high melting point resin, the difference in melting point between the low melting point resin and the high melting point resin being at least 10° C., the low melting point resin forming at least a portion of the surface of the fiber, and the composite spun bonded nonwoven fabric being a partial thermal fusion product of the composite continuous fibers by the mediation of the low melting point resin,
the composite meltblown extra-fine-fiber nonwoven fabric comprises composite meltblown extra-fine fibers composed of a low melting point resin and a high melting point resin, the difference in melting point between the low melting point resin and the high melting point resin being at least 10° C., the low melting point resin forming at least a portion of the surface of the fiber, and the composite meltblown extra-fine-fiber nonwoven fabric being a partial thermal fusion product of the extra-fine fibers by the mediation of the low melting point resin; and
the composite spun bonded nonwoven fabric and the composite melt-blown extra-fine-fiber nonwoven fabric are integrated by fusion of the low melting point resin of the composite spun bonded nonwoven fabric and/or the low melting point resin of the composite meltblown extra-fine-fiber nonwoven fabric.
(2) A laminated nonwoven fabric as described in (1), wherein
the composite spun bonded nonwoven fabric comprises composite continuous fibers having a fineness of 0.5-10 d/f,
the composite meltblown extra-fine-fiber nonwoven fabric comprises extra-fine fibers having a fiber diameter of 0.1-10 &mgr;m, has 10/m
2
or less of polymer particles having a diameter of at least 0.1 mm, and has an apparent density of 0.02-0.20 g/cm
3
; and
the laminated nonwoven fabric has a strength in the lateral direction of 0.6 kg/5 cm or more, uniformity index of 0.6 or less, and a delamination strength between the two layers of 6 g/5 cm or more.
(3) An absorptive product comprising a laminated nonwoven fabric as described in (1) or (2) as at least one component of the product.
(4) An absorptive product as described in (3) wherein the product comprises a nonwoven fabric of double-layer structure composed of a composite spun bonded nonwoven fabric and a composite meltblown extra-fine-fiber nonwoven fabric; or a nonwoven fabric of multi-layer structure comprising at least three layers, composed of a composite spun bonded nonwoven fabric and a composite meltblown extra-fine-fiber nonwoven fabric, and having the composite meltblown extra-fine-fiber nonwoven fabric laminated on at least one side of the laminated nonwoven fabric.
(5) A method of manufacturing a laminated nonwoven fabric comprising the steps of:
spinning composite continuous fibers from a low-melting point resin and a high melting point resin so that at least a portion of the fiber surface is formed by the low-melting point resin, the difference in melting point between the low melting point resin and the high melting point resin being at least 10° C., and forming a spun bonded web by a composite spun bonding method; or heating the resultant fiber web at a temperature not lower than a thermal fusion temperature thereby to form a nonwoven fabric in which some parts of the fibers are thermally fused;
spinning composite meltblown extra-fine-fibers having an average fiber diameter of 10 &mgr;m or less, and comprising a low-melting point resin and a high melting point resin, the difference in melting point between the low melting point resin and the high melting point resin is at least 10° C., in such a fashion that the low-melting point resin forms at least a portion of the fiber surface, and forming a composite extra-fine-fiber web which does not include thermally fused portions by self-heating at the time of spinning, or forming a nonwoven fabric which includes portions thermally fused by self-heating at the
Horiuchi Shingo
Ogata Satoshi
Terakawa Taiju
Chisso Corporation
Edwards N.
Fay Sharpe Fagan Minnich & McKee LLP
LandOfFree
Laminated nonwoven fabric and method of manufacturing same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Laminated nonwoven fabric and method of manufacturing same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Laminated nonwoven fabric and method of manufacturing same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2597868