JPS6349158A - Surface material of absorbable article - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a surface material for absorbent articles such as disposable diapers and sanitary napkins.

[Conventional technology]

BACKGROUND ART Absorbent articles such as disposable diapers that are currently widely used are made of three layers: a surface material, an absorbent material, and a backing material from the side that comes into contact with the skin when worn. In addition to strength and flexibility, the surface material has water permeability to quickly transfer the liquid to be absorbed to the absorbent material, and has absorbency that prevents absorbed bodies from returning to the skin and provides a dry feel to the skin. There is a need for dry touch properties that give
No. 269, No. 4041951 and No. 4391869
Nonwoven fabrics made of hydrophobic fibers are often used, as proposed in No. If the nonwoven fabric is made highly hydrophobic, the dry touch properties of the surface material using it will improve, but the water permeability will decrease, so in order to achieve both properties, it is necessary to add a surfactant to the surface of the hydrophobic fiber. There have been attempts to make it adhere, but satisfactory performance has not been achieved.

[Problem that the invention seeks to solve]

In recent years, demands on absorbent articles have diversified, and those intended for use at night must have appropriate water permeability and dry touch even after absorbing liquid several times. is required. In response to these demands, surface materials using nonwoven fabrics with surfactants attached to the hydrophobic fibers mentioned above lose their surfactant and rapidly decrease water permeability after absorbing liquid for one or two times. There is a drawback. The object of the present invention is to eliminate the drawbacks of conventional surface materials and to provide a surface material for absorbent articles that has both adequate water permeability and dry touch properties even after repeated liquid absorption.

[Failure to solve the problem]

As a result of intensive research to improve the shortcomings of such conventional surface materials, the present inventors found that a hydrophobic resin containing a wetting agent of 0.005 to 10.0% by weight forms a fiber surface with a coefficient of 50 or more. A mixture of sorbitan monooleate and polyoxyethylene sorbitan monooleate in a weight ratio of 1:1 to 9:1 was applied as a finishing agent to a nonwoven fabric made of fibers made of 0.1 to 1.0% of the weight of the nonwoven fabric. The present invention was completed based on the knowledge that the present invention has favorable properties.

In the present invention, the hydrophobic resin refers to a resin having an equilibrium moisture content of 0.5% or less, and specific examples include various polyethylenes, polypropylenes, polyesters, ethylene-vinyl acetate copolymers, and the like. These hydrophobic resins can be used alone or as a mixture.

Wetting agents to be contained in the hydrophobic resin include anionic surfactants such as higher alcohol sulfate ester salts, alkylbenzene sulfonates, higher alcohol phosphate ester salts, and cationic surfactants such as alkyl amine salts and quaternary amine salts. or nonionic surfactants such as polyoxyethylenes, polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters a, polyhydric alcohol alkyl esters, etc., and use them alone or as a mixture. Can be done.

Examples of preferable wetting agents evaluated based on thermal stability during spinning and ability to impart hydrophilicity to hydrophobic resins include general formula (1) C), 1. (OR,)CH(01(2)CI(
2(OI'L, ) (in the formula, OIL, , OR, independently represents a hydroxy group or a fatty acid ester group,
However, at least one is a saturated or unsaturated fatty acid ester, and fatty acids preferably have 12 to 18 carbon atoms) and fatty acid glycerides represented by the general formula (n
) HOCH2CH, (0CH2CH2)nOR4 (in the formula, OR is a saturated or unsaturated fatty acid ester group having 12 to 18 carbon atoms, n is a numerical value of 10 to 55), and a group of these compounds It is possible to indicate a mixture selected from the following.

A method for incorporating the above-mentioned wetting agent into the hydrophobic resin may be the usual heating cross-fertilization method, and a method using an extruder during spinning is simple. The amount of wetting agent contained in the resin is preferably 0.05 to 10.0% by weight.

If it is less than 0.05%, the effect of imparting hydrophilicity is insufficient;
If it exceeds 0.0%, thread breakage occurs during spinning or drawing, and the dry touch properties of the surface material deteriorate, which is not preferable.

The hydrophobic resin containing a wetting agent can be spun by itself or in combination with other resins. As other resins to be combined, it is also possible to use hydrophilic resins such as polyamide in addition to hydrophobic resins that do not contain a wetting agent. In order to perform composite spinning so that the hydrophobic resin containing a wetting agent forms 50% or more of the fiber surface, it is sufficient to place the resin on the sheath component side in the case of a sheath-core type, and in the case of a parallel type. determines the preferred composite ratio by trial and error. Composite has a melting point difference of 20
In the case of a parallel type or sheath-core type composite in which two components having a temperature of ℃ or higher are combined so that the low melting point component occupies 5096 or more of the fiber surface, the resulting composite can be easily dried using a fiber sorption dryer or hot roll. This is preferable because it can be made into a thin and strong nonwoven fabric.

In addition to the above-mentioned heat treatment method, known methods such as a needle punch method and a water needle method can be appropriately selected as a method for making the fibers obtained in this way into a nonwoven fabric.

Sorbitan monooleate and polyoxyethylene sorbitan monooleate used as finishing agents in the present invention are mixtures of various sorbitan monoesters represented by the following formulas (Ill) and (IV), respectively.

where R is C17H33 and Y+ % Y2.
Y, each independently represents a hydroxyl group or -0(CH2CH
20) I (but at least one is 10 (C
H2CH20). H, and n is a number ranging from 10 to 55.

These sorbitan monooleate and polyoxyethylene sorbitan monooleate are mixed in a weight ratio of 1:1 to 9:1, preferably 1:1 to 3:1, and are contained in the nonwoven fabric in an amount of 0.1 to 1.0% ( Heavy) Attach. Adhesion amount is 0.
If it is less than 1%, the water permeability will be insufficient, and if it exceeds 1.0%, the dry touch property will be insufficient. As a method for attaching the mixture to the nonwoven fabric, any known method can be used, such as attaching it to the surface of the fibers using an oiling roll or the like during spinning, or impregnating the nonwoven fabric.

〔Example〕

The present invention will be explained in more detail by Examples and Comparative Examples. The various fibers shown in Table 1 are manufactured using polyethylene, polypropylene, which is a hydrophobic resin, and 6-nylon, which is a hydrophilic resin, and after being mechanically crimped, the fibers are cut into fibers with a length of 56 mm to form a fabric. And so. In each of the above-mentioned fibers, the wetting agent was uniformly kneaded with the predetermined components by supplying it to a spinning extruder. These fabrics were made into webs using a 40-inch roller card, and the webs were repeatedly bound into nonwoven fabrics and tested for water permeability and dry touch properties using the method shown in Table 2. The finishing agent was applied using an oiling roll during spinning in the case of a nonwoven fabric produced by a suction dryer or a hot roll, and was applied by impregnating the nonwoven fabric in the case of a nonwoven fabric produced by a water heater.

Repeated water permeability test: A 20 cm x 20 cm test piece was placed on a door paper of the same size, and water was poured into the center of the test piece from the tip of the billet, which was placed at a height of 20 cm from the surface.
Drop for 5 seconds. After dropping, measure the time until the light reflection from the water droplets on the surface of the test piece disappears (water permeation time). Next, after drying this test piece at 40° C. for 1 hour, the water permeation time is measured again, and this operation is repeated until the water permeation time reaches 3 seconds, and the number of repetitions is displayed.

Place a test piece of dry touch property = 20crrL x 20crrL on the door paper of the same size, and add 1 liter of water to the center of the test piece.
At was dropped for 5 seconds, and after 1 minute, the area where water was dropped was pressed with a hand to test whether there was a wet feeling.

The test results are also shown in Table 2. The various abbreviations in Tables 1 and 2 are as follows.

PP: Polypropylene PE: Polyethylene 6-Nyln: 6-nylon A: Sorbitan monooleate B: Polyoxyethylene sorbitan monooleate (degree of polymerization 20) C Nilauryl phosphate with salt + nrubitan tallow acid ester (1+1 mixture) D Lauryl phosphate with salt + polyoxyethylene lauric acid ester (1+1 mixture, degree of polymerization 9) [Effect] As is clear from the results shown in Tables 1 and 2, the surface material of the present invention repeatedly shows water permeability. It has excellent softness and dry touch properties, and is extremely suitable as a surface material for disposable nighttime diapers that need to repeatedly absorb urine and the like.

that's all

Claims (5)

[Claims] (1) A surface material for an absorbent article made of nonwoven fabric,
This nonwoven fabric is made of fibers in which a hydrophobic resin containing 0.05 to 10.0% by weight of a wetting agent forms 50% or more of the fiber surface, and sorbitan monooleate and polyester are added as finishing agents to the weight of the nonwoven fabric. A mixture with oxyethylene sorbitan monooleate in a weight ratio of 1:1 to 9:1
．． A surface material for an absorbent article, characterized in that 1 to 1.0% of the surface material is deposited. (2) The surface of the absorbent article according to claim 1, wherein the wetting agent is one or more compounds selected from fatty acid monoglycerides, fatty acid diglycerides, fatty acid triglycerides, and polyoxyalkylene fatty acid esters. Material. (3) The surface material for an absorbent article according to claim 1, wherein the hydrophobic resin is polyethylene. (4) The surface material for an absorbent article according to claim 1, wherein the hydrophobic resin is polypropylene. (5) The surface material for an absorbent article according to claim 1, wherein the fiber is a composite fiber made of two or more types of hydrophobic resins having different melting points.