JPH0430847A - Expandable composite sheet - Google Patents

Abstract

PURPOSE:To obtain a sheet for a steam-free and disposable diaper with no urine leakage by a method wherein a non-expandable unwoven cloth is thermocompression bonded on the surface and rear of an intermediate layer comprising a bare polyurethane resin elastic yarn well trimmed and with density of the elastic yarn specified, the non-expandable unwoven cloth is drawn in a direction of orienting the elastic yarn to form a gathering. CONSTITUTION:Bare polyurethane elastic yarn is not covered with a nylon yarn or the like and the size thereof is preferably 100-500 denier. Density of the elastic yarn is 1-10 pieces per cm. A non-expandable unwoven cloth is composed of synthetic fibers such as polyester, nylon, and cellulose such as rayon, cotton. The elastic yarn 1 is arranged as intermediate layer being stretched and kept in a form of a final composite sheet. Then, it is released from the stretching. The non-expandable unwoven cloths 2 and 3 are thermocompression bonded on the surface and rear of the intermediate layer with a heating emboss roll, for instance. A sheet can be produced simply with varied elongation and stretching stress by varying conditions of the elastic yarn. When this sheet is used for an opening of a disposable diaper, it excels in mobility and fitness with no steaming.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a stretchable composite sheet.

More specifically, the present invention relates to a stretchable composite sheet useful for the opening or abdomen of a disposable diaper.

[Conventional technology]

Conventionally, stretchability has been imparted to nonwoven fabrics used in disposable diapers. For example, the diaper disclosed in Japanese Unexamined Patent Publication No. 58-18060 has a top sheet made of nonwoven fabric or the like,
Rubber thread is glued between the pack sheet made of plastic film, etc. However, since this diaper uses a plastic film, it has the disadvantage of becoming stuffy.

Furthermore, in the stretchable composite sheet disclosed in JP-A No. 62-2845'6, since the elastic body is a web made of elastic fibers, the stretchability cannot be set appropriately, and it cannot be adjusted to fit each infant. It was not possible to obtain an elastic part for disposable diapers.

[Problem to be solved by the invention]

The present invention aims to overcome the above-mentioned drawbacks of the stretchable composite sheets used in conventional diapers, and to provide a stretchable composite sheet that fits each infant perfectly, does not leak urine, and does not get stuffy.

[Means to solve the problem]

The present invention is a composite sheet in which an intermediate layer made of aligned bare polyurethane elastic threads and a non-stretchable nonwoven fabric are integrated by thermocompression bonding on both sides of the intermediate layer, and the density of the polyurethane elastic threads is 1 to 10 threads/cm, and is characterized in that the non-stretchable nonwoven fabric is formed with gears drawn in the direction in which bare polyurethane elastic threads are arranged.

Here, the bare polyurethane elastic thread used in the present invention refers to one that is not covered with nylon thread or the like. The thickness is preferably from 100 deniers to 500 deniers.

Density of bare polyurethane elastic yarn used in the present invention is 1~
10 lines/cm. If it is less than 1 thread/cm, the fit will be poor and wetting will not be prevented, and the pitch of the gears will be too thick (too much, and the appearance will be bad). be.

In the stretchable composite sheet of the present invention, the thickness and number of the bare polyurethane elastic threads are appropriately set according to the age, age, body shape, and gender-specific stretchability, stretch stress, and stretch recovery power of the stretchable part of the infant. However, by changing the elongation rate when flattening, it is possible to accommodate any elongation, elongation stress, and elongation recovery force.

The non-stretchable nonwoven fabric as used in the present invention refers to a fabric made of synthetic fibers such as polyester, nylon, polypropylene, and acrylic, as well as rayon and linear cellulose.

In the stretchable composite sheet of the present invention, the non-stretchable nonwoven fabrics that are thermocompression bonded to both the front and back surfaces of the intermediate layer made of polyurethane elastic threads may be the same material or different materials, as long as at least one of them is thermocompression bondable.

The stretchable composite sheet of the present invention is made by integrating bare polyurethane elastic threads and non-stretchable nonwoven fabric by thermocompression bonding. The thermocompression bonding may be partial compression bonding or full pressure bonding. The temperature required for thermocompression bonding can range from 50°C lower than the melting point of the low melting point synthetic fiber of the non-stretchable nonwoven fabric to the melting point.

As described above, since the present invention is integrated without using an adhesive, there is no risk of skin damage due to irritation from the adhesive, see-through, which makes the surface hard and irritates the skin, and odor.

Hereinafter, explanation will be given with reference to FIG. 1. After the bare polyurethane elastic yarn (1) is placed as an intermediate layer in an elongated state and maintains the form of the scarlet composite sheet, the elongation is removed. The non-stretchable nonwoven fabrics (2) and (3) are bonded by thermocompression bonding to both the front and back surfaces of the intermediate layer made of elastic thread. The part that is thermocompressed here is the part (4) between adjacent elastic systems, and the bare polyurethane elastic thread (1) and non-stretchable nonwoven fabric (2) and (3) are not bonded. may also be combined.

The thermocompression bonding method for the stretchable composite sheet of the present invention may be any method that applies heat and pressure. For example, you can easily heat and press the edges with a heated embossing roll.

An example of a manufacturing method includes a method in which aligned elastic threads are roughened and stretched, a non-stretchable nonwoven fabric is placed on both the front and back sides, and the fabric is passed through a heated embossing roll to be thermocompressed.

〔Example〕

Next, the present invention will be specifically explained with reference to Examples. The physical properties of the stretchable composite sheet were measured in accordance with JIS L1096.

Example 1 150% 420 denier bare polyurethane elastic yarn
The middle layer is made by elongating the fibers and aligning them at a density of 2 fibers/cm, and the basis weight is 23g/r+? A polypropylene nonwoven fabric made by a spunbond method was placed on both the front and back sides of the intermediate layer. Then, a stretchable composite sheet was obtained by thermocompression bonding by passing the pin roll through a heated embossing roll heated to 135°C and the smooth metal roll to 145°C. The thickness of the gears part of the obtained stretchable composite sort was 3.
5 mm, and the number of gears was 3 to 4 pieces/cm. In addition, the physical properties are: elongation 106%, elongation stress 0.3kg/S
crn width.

Example 2 200% 280 denier bare polyurethane elastic yarn
A polypropylene nonwoven fabric having a basis weight of 20 g/rrf and made by a spunbond method was placed on both the front and back sides of the intermediate layer. Then, by passing the pin roll through a heated embossing roll heated to 135°C and the smooth metal roll to 145°C, thermocompression bonding was performed to obtain a stretchable composite sheet. The obtained elastic composite sheet had a thickness of 1.5 mm at the gear portion, a number of gears of 10 to 14 pieces/cm, and physical properties of an elongation of 194% and an elongation stress of 1 to 0 kg/5 cm width.

Example 3 200% 420 denier bare polyurethane elastic yarn
A polypropylene nonwoven fabric made by a spunbond method and having a basis weight of 15 g/rrf was placed on both the front and back surfaces of the intermediate layer. The bottle roll was then thermocompressed by passing the 135°C smooth roll through a heated embossing roll heated to 145°C to obtain a stretchable composite sheet. The thickness of the geared portion of the obtained stretchable composite sheet was 1.5 mm, the number of gears was 10 to 14 pieces/cm, and the physical properties were elongation of 248%.
The elongation stress was 0.9 kg/5 cm width.

As described above in Examples 1 to 3, stretchable composite sheets having various elongations and elongation stresses can be easily produced by changing the conditions of the bare polyurethane elastic yarn.

When these stretchable composite sheets were used in the openings of disposable diapers, they were moderately tight, did not leak urine, and had good mobility.

〔Effect of the invention〕

When the stretchable composite sheet of the present invention is used in the opening of a disposable diaper, it follows body movements well, has excellent maneuverability and fit, prevents urine from leaking sideways, and is breathable and prevents stuffiness. Yes. In addition, it has various effects such as being thin and not bulky, and since no adhesive is used, there is no risk of skin damage due to irritation.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of the stretchable composite sheet of the present invention. 1-・--1--Bare polyurethane elastic system 2.3-
non-stretch non-woven fabric

Claims (1)

[Claims] 1. A composite sheet in which an intermediate layer consisting of aligned bare polyurethane elastic yarns and non-stretchable nonwoven fabrics are integrated on both the front and back sides of the intermediate layer by thermocompression bonding, and the density of the bare polyurethane elastic yarns is 1 to 1. 10 fibers/cm, and the non-stretchable nonwoven fabric is drawn in the direction of arrangement of bare polyurethane elastic threads to form gathers.