JPH0257254A - Liquid leakproof sheet - Google Patents

Abstract

PURPOSE:To obtain a flexible liquid leakproof sheet generating no local liquid sump because of high leakproofness and good liquid diffusibility and having no feeling of physical disorder by constituting one surface of a liquid impermeable sheet or film of a hydrophilic fine fiber composed of a thermoplastic polymer. CONSTITUTION:A liquid impermeable sheet 1 or film constituting a leakproof sheet is composed of an unperforated sheet or film obtained by the melt-molding of a thermoplastic polymer or a sheet 3 or film having fine pores. Further, it is necessary to impart hydrophilicity to a nonwoven fabric 2. Therefore, a hydrophilic polymer is used in the polymer constituting the fiber of said fabric 2 or, when a hydrophobic polymer is used, a hydrophilic or a water- absorbable substance is preliminarily compounded with the polymer to be used or a water-absorbable polymer is applied to the melting or spinning system of the polymer. Next, the nonwoven fabric 2 and the liquid impervious sheet 1 or film are laminated and integrated at least partially by heat-treatment, high frequency treatment or ultrasonic treatment to obtain a required sheet.

Description

[Detailed Description of the Invention] [Industrial Application Fields] The present invention is applicable to sanitary napkins, paper diapers, bats for incontinence,
This invention relates to a liquid-impermeable leak-proof sheet for sanitary products that covers the outside or back side of absorbent articles that mainly absorb liquid, such as postpartum vats and breast milk vats.

[Prior Art] Conventionally, many products have been developed as sanitary products for absorbing body fluids. Sanitary products have various performance requirements depending on their use, but the surface that comes into contact with the skin is particularly rigorously evaluated in terms of feel, texture, and wearability, so many proposals have been made for facing materials for sanitary products. . However, the liquid-impermeable leak-proof sheet that covers the outside of sanitary products, that is, the back sheet, only has the function of preventing liquid leakage, so it is generally made of plastic film such as polyethylene, nonwoven fabric, or paper and polyethylene film. Laminated products are used.

For example, JP-A-56-15743, JP-A-6311
It is described in Publication No. 7753.

[Problem to be solved by the invention] Conventionally, liquid leak proof sheets for sanitary products have poor affinity with liquids, so liquid accumulates locally on the leak proof sheet surface and flows from the leak proof sheet surface to absorbent substances. The diffusion and absorption of liquid is poor. In addition, with leak-proof sheets made by laminating liquid-impermeable sheets or films and liquid-diffusing sheets such as valve paper, there is a limit to manufacturing thin leak-proof sheets due to the processability of the leak-proof sheets. The weight of the leak-proof notebook in the product cannot be ignored.

An object of the present invention is to provide a liquid leak-proof sheet for sanitary products that has high leak-proof properties and good liquid dispersibility, does not cause local accumulation of liquid, and is flexible. Furthermore, by laminating the liquid diffusion sheets in advance, it is possible to rationalize product manufacturing.

[Means for Solving the Problems] The present invention provides a liquid-impermeable sheet or film with:
A laminated sheet in which nonwoven fabrics made of hydrophilic fine fibers made of a thermoplastic polymer and/or fine fibers imparted with a hydrophilic agent, at least a portion of which is in contact with the fibers are fused, are laminated and at least a portion of which is integrated. This is a liquid leak-proof sheet for sanitary products characterized by:

Furthermore, the present invention has a moisture permeability of at least 200 g/m".2
A nonwoven fabric composed of hydrophilic fine fibers made of a thermoplastic polymer and/or fine TA fibers imparted with a hydrophilic agent is laminated on one side of a liquid-impermeable sheet or film that is 4 hours, and at least a portion thereof is integrated. This liquid leak-proof sheet for sanitary products is characterized by being a laminated sheet.

In addition, the present invention melt-extrudes a hydrophilic polymer and/or a hydrophobic polymer that is a thermoplastic polymer, spins it into fine fibers that are not fiber bundles using a high-temperature, high-pressure gas flow, and aggregates them into a fiber web, and as needed. When obtaining a nonwoven fabric by pressure treatment with or without heating, at least a hydrophilic substance or a water-absorbing substance is added to the hydrophobic polymer or the melting system or spinning system of the hydrophobic polymer, and the melt-blowing process is performed. A nonwoven fabric made of hydrophilic fine fibers and/or hydrophilic agent-imparted fine fibers is produced by spinning, and a liquid-impermeable sheet or film is laminated on one side of the nonwoven fabric, and at least a portion thereof is integrated as necessary. This is a method for producing a liquid leak-proof sheet for sanitary products, characterized in that it is processed into a laminated sheet.

The liquid-impermeable sheet or film constituting the leak-proof sheet of the present invention is a nonporous sheet or film obtained by melt-molding a thermoplastic polymer, or a sheet or film having micropores. Also, as another method,
A sheet-like material having micropores obtained by heat-treating and/or hot press molding a spunbond fiber web obtained by spinning a thermoplastic polymer, a melt-blown fiber web, or a fiber web obtained by a dry method or a wet method. Alternatively, it is a film-like material, or a nonporous sheet-like material or film-like material. It is preferable that these sorts or films (hereinafter simply referred to as sheets or films) have thermal adhesive properties. Furthermore, it is preferred that the sheet or film is impermeable to liquids but permeable to vapors. That is, J as a sort or a film alone or as a leak-proof sheet of the present invention.
The moisture permeability measured according to IS Z-0208 (Moisture Permeability Test Method for Moisture-Proof Packaging Materials) is at least 500g/11"
・24hrs, preferably 8QOg/m' ・24hrs
It is preferable that it is s or more. A method of imparting moisture permeability is to use a sheet or film with a large number of micropores! However, such moisture-permeable sheets or films can be produced by heating, pressing with a roll with a rough surface or a roll with a smooth surface, high frequency or Processes such as ultrasonic irradiation, electrical discharge machining, needle punching, and stretching are performed. Another method is to perform foaming during the production of the sheet or film and transform it into micropores during the production of the laminated sheet. If liquid permeability occurs due to the formation of a large number of micropores, the size of the pores may be adjusted again by thermal imaging. Further, the thermoplastic polymer used in the present invention is not particularly limited as long as it is a thermoformable polymer, especially a polymer having thermal adhesive properties. Preferred polymers include polyolefins such as polyethylene, ethylene copolymers, polypropylene, polybutylene, and butylene copolymers, polyesters, vinyl chloride copolymers, polyamides, thermoplastic polyurethanes, etc. in view of product flexibility and ease of processing. At least one polymer selected from the following is used.

Next, the nonwoven fabric of the present invention is produced by melt-extruding a hydrophilic polymer and/or a hydrophobic polymer that is a thermoplastic polymer, spinning it into fine fibers that are not fiber bundles using a Toriya high-pressure gas flow, and consolidating them into a fiber web. A fibrous web is made using the melt blown method. Further, the nonwoven fabric of the present invention needs to be imparted with hydrophilicity. To this end, it is necessary to use a hydrophilic polymer as the polymer that makes up the fiber, or even if it is a hydrophobic polymer, it is necessary to add a hydrophilic substance or a water-absorbing substance to the polymer in advance, or to A hydrophilic substance or a water-absorbing substance is applied in the coalescing melting system or spinning system (at any stage such as in the spinning nozzle, in the gas flow, or in the ejected fiber stream). Alternatively, fibers to which a hydrophilic agent has been added can be obtained by treating the accumulated fiber web to impart a hydrophilic substance to the fiber web.

The hydrophilic substances imparted to the fibers include, for example, ethylene oxide-added surfactants, nonionic surfactants,
Polyethylene oxide, polyvinyl alcohol, vinyl alcohol copolymers, higher alkyl phosphate ester salts, higher alcohols, fatty acid esters of polyhydric alcohols, etc., and water-absorbing organic polymers such as olefin-unsaturated carboxylic acid copolymer anhydrides, acrylics. A substance selected from resins or fine powders of hygroscopic inorganic materials is blended or attached. Another method is to use a mixture of polymers obtained by graft polymerizing hydrophilic groups.

Further, the hydrophilic polymer constituting the nonwoven fabric fibers is a polymer selected from, for example, polyvinyl alcohol, vinyl alcohol copolymer, polyethylene ethylene copolyester, and the like. Examples of hydrophobic polymers include polyolefins or olefin copolymers such as polyethylene, ethylene copolymers, polypropylene, and polybutylene, and nylon-6
, nylon-66, nylon-610, nylon-11
A spinnable polymer selected from polyamides such as , nylon-12, polyesters such as polyethylene terephthalate, ethylene terephthalate copolymers, polybutylene ethylene phthalate, and thermoplastic polyurethanes, and the polymers may be used singly or in combination. Spinning. The basis weight of the nonwoven fabric obtained by spinning varies depending on the desired sanitary product, and is generally in the range of 3 to 200 g/m'.

The hydrophilicity of the nonwoven fabric was determined by stacking 10 sheets of Gapaper (Product No. 5, manufactured by Toyo Gapaper Co., Ltd.) as a liquid absorber.
Place the nonwoven fabric to be measured on top of it, drop 1 mQ of physiological saline, and judge by the time it takes until there are no water droplets on the surface. rated it as.

The nonwoven fabric of the present invention is one that has an absorption time of physiological saline within 2 seconds.

Next, a laminated sheet is obtained by laminating a nonwoven fabric and a liquid-impermeable sheet or film, and at least a portion of which is integrated by heat treatment, high frequency treatment, or ultrasonic treatment. In addition, the nonwoven fabric is made by laminating and integrating multiple nonwoven fabrics with different hydrophilic properties.
For example, by laminating a highly hydrophilic nonwoven fabric on the absorbent side, micropores are made in a liquid-impermeable sheet or film to impart air permeability, making it suitable for making sanitary products that do not leak. be.

Next, the structure of the liquid leakage prevention sheet of the present invention will be explained with reference to the drawings. FIG. 1, FIG. 2, and FIG. 3 are schematic diagrams showing an example of a laminated deaf sheet of the leak-proof sheet of the present invention. Figure 1 is a schematic diagram of a leak-proof sort made by laminating a liquid-impermeable sheet and a non-woven fabric, and Figure 2 is a schematic diagram of a leak-proof sort made by laminating a liquid-impermeable sheet and two layers of non-woven fabric with different hydrophilic properties. FIG. 3 is a schematic diagram of leakage sorting, and FIG. 3 is a schematic diagram of a leakproof sheet made by laminating and integrating a liquid-impermeable notebook with micropores and a nonwoven fabric. and,
In the figure, 1 is a liquid-impermeable sheet, 2 is a hydrophilic nonwoven fabric, 2' is a hydrophilic nonwoven fabric with different degrees of hydrophilicity, and 3 is a micropore drilled in the liquid-impermeable notebook.

The liquid leak-proof sheet for sanitary products of the present invention includes sanitary napkins,
It is used as a leak-proof sheet for sanitary products that covers the back or outside of absorbent materials that mainly absorb liquid, such as disposable diapers, incontinent bats, postpartum bats, and breast milk bats.

[Example〕 Embodiments of the present invention will be explained below using specific examples.

In addition, parts and percentages in the examples refer to weight unless otherwise specified.

Example 1 A composition of 50% low-density, high-flow polyethylene and 50% hydrophilized polyethylene was melt-extruded using an extruder, spun into a fine fiber stream using a heated high-pressure air stream using a melt-blowing die, and captured. A fibrous web with an average basis weight of 18 g/m'' was made by accumulating it into an aggregate, and a nonwoven fabric with a part of the fiber contact area fused was obtained by calender pressing.The hydrophilicity of this nonwoven fabric was 0.9 seconds. .

Next, the nonwoven fabric was laminated with a polyethylene thin film and thermally bonded to create a leak-proof sheet. Using this leak-proof sheet, an absorbent material mainly made of pulp is placed on the non-woven fabric surface and covered with a fencing material to make a sanitary bat, and a dye-colored saline solution is dropped to check the state of penetration and diffusion of the liquid. Examined. As a result, the liquid that reached the back surface was transmitted through the nonwoven fabric layer and was absorbed by the absorbent material from the back side.

For comparison, a sanitary bat was made using a polyethylene film as a leak-proof sheet in the same manner as in Example 1, and the state of liquid penetration and diffusion was investigated in the same manner.As a result, there was almost no liquid diffusion from the back side, and the absorption The absorption rate of the liquid was rate-limiting.

Example 2 Composition (80:
17:3) is melted in an extruder, spun into a fine fiber stream using a heated high-pressure air stream using a melt-blowing die, and collected in a collecting body to obtain an average basis weight of 13 g/n''.
A fibrous web-1 was prepared. The hydrophilicity of this fiber web was 0.7 seconds.

Next, the fibrous web-I is laminated on a low-density polyethylene film, the polyethylene film is brought into contact with the finely uneven surface of the satin pattern, and then heated and embossed using an embossing device using a heating-cooling method to form fine ventilation holes on the film surface. At the same time, the film and the fiber web were integrated, and a part of the fiber contact area was fused to obtain a leak-proof sheet. The moisture permeability of this leak-proof sheet was 3560 g/I++"・24 hrs.

When this leak-proof sheet was used for the outer packaging of a breast milk vat,
It was flexible, had good conformability to the skin, and did not cause itchy feeling.

Example 3 The fibrous web-1 produced in Example 2 and the fibrous web-I were further treated with an ethylene oxide-added nonionic surfactant to produce a fibrous web-■ whose hydrophilicity was increased to 0.7 seconds or less. Laminate two IS webs and combine them to form a fiber web I
An ethylene copolymer film was placed on the side and fused together using ultrasonic treatment to create a leak-proof sheet.

When paper diapers were made using this leak-proof sheet, the liquid was quickly absorbed and diffused from the inside, and the amount of liquid backflow was approximately 43% lower than that of a product using only polyethylene film for the leak-proof notebook. A decrease in reflux flow was observed. Furthermore, since it was flexible, it felt good when worn.

[Effects of the Invention] The liquid leak-proof sheet for sanitary products of the present invention has good liquid dispersibility, so it does not cause local accumulation of liquid, reduces the amount of liquid backflow, and has a large number of fine particles. It is also possible to impart air permeability and moisture permeability using a sheet or film having holes, thereby reducing the feeling of stuffiness when worn. Furthermore, since it can be made with flexibility, sanitary products that are comfortable to touch can be obtained. Furthermore, by integrating the liquid leakage prevention sheet and the liquid diffusive sheet in advance, the manufacturing process can be streamlined.

[Brief explanation of the drawing]

FIGS. 1, 2, and 3 are schematic diagrams showing an example of a laminated state of a liquid-impermeable material and a nonwoven fabric constituting the leak-proof notebook of the present invention. Patent applicant RiRa 1no Co., Ltd.

Claims (1)

[Claims] (1) A nonwoven fabric composed of hydrophilic fine fibers made of a thermoplastic polymer and/or fine fibers imparted with a hydrophilic agent, and at least a portion of the fiber contact area is fused to one surface of a liquid-impermeable sheet or film. A liquid leak-proof sheet for sanitary products, characterized in that it is a laminated sheet in which at least a portion of the sheets are laminated and integrated.