JPH09309169A - Composite sheet, article of absorption characteristics and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite sheet of high bonding strength for which the generation of blocking is prevented. SOLUTION: A composite sheet 20 is formed by bonding a sheet 21 with a non-woven cloth 22 by a bonding agent 23, and the sheet 21 is a liquid non- permeable sheet of thickness of 15-40μm, and the non-woven cloth 22 is provided with the fiber diameter of 1.5-3.5 denier and the basis weight of 10-35g/m<2> , and amorphous polyalphaolefin(APAO) of 20wt.% or more is contained as a constituent in the bonding agent 23, and its melting viscosity is 500-10,000 CPS at 180 deg.C, and its coating quantity is 0.5-7g/m<2> .

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a composite sheet useful as a back sheet for absorbent articles such as disposable diapers. The present invention also relates to an absorbent article using the composite sheet and a method for manufacturing the absorbent article.

[0002]

2. Description of the Related Art In recent years,
In an absorbent article such as a disposable diaper, in order to prevent stuffiness inside the absorbent article and to improve texture and touch, a moisture permeable sheet and a non-woven fabric are formed on the back surface material as the outermost layer, SIS (styrene-isoprene-). Styrene) and SB
A composite sheet in which S (styrene-butadiene-styrene) or a mixture thereof is used as a base and is joined by a so-called rubber-based hot-melt adhesive is used.

When a disposable diaper is manufactured using the composite sheet, for example, the disposable diaper is generally manufactured while unrolling the rolled composite sheet. In this case, in consideration of the texture such as the softness and touch of the disposable diaper, if a thin and coarse non-woven fabric is used as the non-woven fabric in the composite sheet, when the composite sheet is in a roll state, the pressure is applied to the composite diaper. There is a problem that the adhesive oozes out onto the surface of the non-woven fabric and adheres to the adjacent composite sheet in the roll, that is, the problem of blocking occurs. When the composite sheet is unwound in the state where blocking occurs, the composite sheet may be broken or entangled with the roll without unwinding.

On the other hand, if the coating amount of the adhesive is reduced in order to avoid the problem of blocking, the adhesive strength between the moisture permeable sheet and the non-woven fabric is reduced, and the backing material for absorbent articles such as disposable diapers. Will be unsuitable as

Accordingly, it is an object of the present invention to provide a composite sheet having high adhesive strength and preventing the occurrence of blocking. Another object of the present invention is to provide an absorbent article in which stuffiness is prevented and the texture such as softness and touch are improved. Further, the object of the present invention is to
An object of the present invention is to provide a method for producing an absorbent article in which the adhesive strength of the composite sheet is improved and unwinding trouble due to the occurrence of blocking of the composite sheet is prevented.

[0006]

Means for Solving the Problems As a result of intensive studies by the present inventors, a composite sheet obtained by joining a sheet having specific physical properties and a non-woven fabric having specific physical properties with an adhesive having specific physical properties is described above. It was found that the purpose could be achieved.

The present invention has been made based on the above findings, and in a composite sheet in which a sheet and a non-woven fabric are joined with an adhesive, the sheet has a thickness of 15 to 40 μm.
m is a liquid impermeable sheet, and the nonwoven fabric has a fiber diameter of 1.5 to 3.5 denier and a basis weight of 10 to 10.
35 g / m ² , and the adhesive has amorphous polyalphaolefin (APA) as its constituent component.
O) is contained in an amount of 20% by weight or more, and its melt viscosity is 180 ° C.
It is 500-10,000 cps and the coating amount is 0.5-7 g / m < ² >, and the said objective was achieved by providing the composite sheet characterized by the above-mentioned.

Further, the present invention provides an absorbent article comprising a liquid-permeable surface material, a liquid-impermeable back material, and an absorber interposed between the surface material and the back material. It is intended to provide an absorbent article characterized by using the above composite sheet as a backing material.

The present invention also provides a method for manufacturing an absorbent article using a composite sheet obtained by joining a sheet and a non-woven fabric with an adhesive as a backing material, wherein the sheet has a liquid impermeability of 15 to 40 μm. The nonwoven fabric is a sheet, and the nonwoven fabric has a fiber diameter of 1.5 to 3.0 denier and a basis weight of 10 to 35 g / m ² , and the adhesive has an amorphous polyalphaolefin ( APAO) in an amount of 20% by weight or more, the melt viscosity at 180 ° C. is 500 to 10,000 cps, the coating amount is 0.5 to 7 g / m ² , and the adhesive is placed on the sheet. The present invention provides a method for producing an absorbent article, which comprises coating and laminating the non-woven fabric on the coated surface, and then joining the sheet and the non-woven fabric by a predetermined joining means.

Further, in the present invention, in the method for producing a composite sheet in which a sheet and a non-woven fabric are joined with an adhesive, the above-mentioned sheet is a liquid impermeable sheet having a thickness of 15 to 40 μm, and the above-mentioned non-woven fabric is obtained by Fiber diameter is 1.5-3.
The denier is 0 denier, the basis weight is 10 to 35 g / m ² , and the adhesive contains 20% by weight or more of amorphous polyalphaolefin (APAO) as its constituent component, and its melt viscosity is 500 at 180 ° C. ~ 10,000
cps, the coating amount is 0.5 to 7 g / m ² , and the adhesive is coated on the sheet, and the nonwoven fabric is bonded on the coated surface, and then by a predetermined joining means. The present invention provides a method for producing a composite sheet, which comprises joining the sheet and the non-woven fabric.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the composite sheet of the present invention will be described below with reference to the drawings. Here, FIG. 1 is a schematic cross-sectional view showing the structure of a preferred embodiment of the composite sheet of the present invention.

The composite sheet 20 shown in FIG.
And the non-woven fabric 22 are joined by an adhesive 23. As the sheet 21, the nonwoven fabric 22, and the adhesive 23 in the composite sheet 20, those having the following physical properties are used. The sheet 21 is a liquid impermeable sheet having a thickness of 15 to 40 μm. The nonwoven fabric 22 has a fiber diameter of 1.5 to 3.5 denier and a basis weight of 15 to 35 g / m ² . -Amorphous polyalphaolefin (hereinafter referred to as "APAO") as a constituent component of the adhesive 23.
Is contained in an amount of 20% by weight or more, and its melt viscosity is 180 ° C.
00-10,000 cps and the coating amount is 0.5
~ 7 g / m ² . Hereinafter, (1) the sheet 21, (2) the nonwoven fabric 22 and (3) the adhesive 23 will be described in detail.

[(1) Sheet] As the sheet 21, a liquid-impermeable film-like sheet having the above-mentioned thickness is preferably used. As the sheet 21, either a moisture-permeable sheet or a moisture-impermeable sheet can be used. Of these sheets, the moisture permeable sheet is likely to emit water vapor, and therefore, when the composite sheet 20 having the moisture permeable sheet is used as a back sheet of a disposable diaper as described later, stuffiness inside the diaper and the wearer associated therewith Skin irritation is effectively prevented. The moisture-permeable sheet and the moisture-impermeable sheet will be described below.

[(1) -1 Moisture Permeation Sheet] The above sheet 2
The moisture permeable sheet used as a 1, its moisture permeation amount preferably ^{0.5~4g / (100cm 2 · h)} , more preferably 1.0 to 2.5 g / (100 cm ²
• What is h) is used. The moisture vapor transmission rate is 0.5g
When the composite sheet 20 is used as a back sheet of absorbent articles such as disposable diapers as described below, the stuffiness inside the diaper and the skin irritation of the wearer accompanying it are not satisfied when the composite sheet 20 is less than / (100 cm ² · h). It cannot be sufficiently prevented, and if it exceeds 4 g / (100 cm ² · h), leakage of liquid such as urine may occur. In addition, the above-mentioned moisture permeability is based on JIS
It is a value measured according to Z 0208.

As described above, the moisture permeable sheet has a thickness of 15 to 40 μm, more preferably 20 to 40 μm.
It is 35 μm. If the thickness is less than 15 μm, it may be difficult to control the thickness during the production of the moisture-permeable sheet. Further, it is likely to be broken when it is bonded to the nonwoven fabric 22 or when manufacturing an absorbent article such as a disposable diaper. On the other hand, when the thickness is more than 40 μm, the texture such as softness and touch of the composite sheet 20 may be deteriorated.

The basis weight of the moisture-permeable sheet is not particularly limited, but it is preferably 15 to 40 g / m ² from the viewpoint of difficulty in controlling the thickness at the time of production, and the feel and touch, and preferably 20 to 35 g. / M ² is more preferable.

The moisture permeable sheet is preferably a porous sheet having a large number of fine holes. The porous sheet can be obtained by a method known in the art, for example, by kneading a polyolefin resin with a filler and subjecting the film or sheet obtained by melt molding to uniaxial or biaxial stretching.

As the above-mentioned polyolefin resin, for example, one containing a monoolefin polymer or copolymer such as ethylene, propylene or butene as a main component is used.
For example, examples of the polyolefin resin include high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polypropylene, crystalline ethylene-propylene block copolymer, polybutene, ethylene-vinyl acetate copolymer, and mixtures thereof. Among them, linear low-density polyethylene is desirable because it is flexible and tough.

As the filler, inorganic and organic fillers are used. As the inorganic filler, calcium carbonate, gypsum, talc, carbon black, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, barium carbonate, magnesium sulfate, barium sulfate, calcium sulfate, calcium phosphate, aluminum hydroxide, zinc oxide, hydroxide. Magnesium, calcium oxide, magnesium oxide, titanium oxide, alumina, mica, asbestos powder, shirasu balloon, zeolite, silicate clay, cement, silica fume, mica powder and the like are preferable. On the other hand, as the organic filler, wood powder, coal powder, pulp powder or the like is used. These fillers may be used alone or as a mixture.

The average particle size of the filler is preferably 30 μm or less, more preferably 10 μm or less, most preferably 0.5 μm to 5 μm. The filler is preferably surface-treated from the viewpoint of uniform dispersibility in the polyolefin resin. For the surface treatment, a fatty acid or a metal salt thereof that can make the surface hydrophobic is preferably used. The mixing ratio of the filler is preferably 50 to 250 parts by weight with respect to 100 parts by weight of the polyolefin resin.

The polyolefin resin may contain various third components for the purpose of improving various properties of the porous sheet. For example, for the purpose of improving the tear strength in the stretching direction and the tensile stress in the transverse direction of the porous sheet, an olefinic low melting point polymer, a liquid or waxy hydrocarbon polymer, a rubber-like material (for example, natural rubber, isoprene). Rubber, butadiene rubber, etc.), olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, or plasticizer can be added.

Further, for the purpose of improving the sheet strength of the porous sheet and forming continuous pores in the porous sheet even at a low draw ratio, triglyceride is preferably added to 100 parts by weight of the polyolefin resin. -100 parts by weight can be added. The fatty acid forming the triglyceride is preferably a saturated or unsaturated fatty acid having 2 to 30 carbon atoms. For the same purpose,
Paraffin chloride can also be used as the third component.
In this case, the chlorine content is preferably 1 to 65% by weight
Of chlorinated paraffins, more preferably 35 to 55% of chlorinated paraffins are used. Such chlorinated paraffin is
It is produced by a known method, for example, by passing chlorine gas through molten solid paraffin, n-paraffin or a carbon tetrachloride solution of solid paraffin. The mixing ratio of chlorinated paraffin is 1 to 100 parts by weight of the above-mentioned polyolefin resin.
Preferably it is 100 parts by weight. For the same purpose, a mixture of a monoester composed of a monobasic acid and a monohydric alcohol and a polyester composed of a polybasic acid and a polyhydric alcohol can be used. Examples of the above-mentioned monoester include esters obtained by dehydration condensation from monobasic acids such as monocarboxylic acids having 10 or more carbon atoms and monohydric alcohols such as monoalcohols having 10 or more carbon atoms. A monoester having a molecular weight of 240 or more, and more preferably a monoester having a branched hydrocarbon chain and having 20 or more carbon atoms is used. On the other hand, as the polyester, for example, a polybasic acid such as dicarboxylic acid, tricarboxylic acid or tetracarboxylic acid, and a polyhydric alcohol such as diols, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol or sucrose. Examples of the polyester obtained by dehydration condensation have a total carbon number of 50 or more.
The mixing ratio of the mixture of the monoester and the polyester is preferably 5 to 50 parts by weight with respect to 100 parts by weight of the polyolefin resin. It is considered that the monoester contributes to the improvement of the moisture permeability and the vertical tear strength of the resulting porous sheet, and the polyester contributes to the improvement of the moisture permeability and the appearance. Further, for the same purpose, a mixture of polyester A composed of a polybasic acid and a monohydric alcohol and polyester B composed of a polybasic acid and a polyhydric alcohol can be used. The polyester A is, for example, a diester, triester or tetraester obtained by dehydration condensation of a polybasic acid such as dicarboxylic acid, tricarboxylic acid or tetracarboxylic acid and a monohydric alcohol and has a total carbon number of 30. The above is mentioned. Of these, the saponification value is 230
The following diesters are preferable, and diesters containing a branched monohydric alcohol having 16 or more carbon atoms are more preferable.
On the other hand, examples of the polyester B include polybasic acids such as dicarboxylic acid, tricarboxylic acid or tetracarboxylic acid, and polyhydric alcohols such as diols, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol or sucrose. Is a polyester obtained by dehydration condensation and has a total carbon number of 50
The above is mentioned. The mixing ratio of the mixture of the polyester A and the polyester B is preferably 5 to 50 parts by weight based on 100 parts by weight of the polyolefin resin.

Further, in order to improve the bamboo tear strength while maintaining the supple texture and the good moisture-permeable leakproof property in the porous sheet, the monoester having a total carbon number of 38 or more is used. At least one of the acid and alcohol forming the ester may be branched. Specific examples of the monoester include 2-decyl tetradecyl stearate, 2-octadecyl behenate, and an ester of α-branched fatty acid (C18-40) and monoalcohol (C6-36) (total carbon number of 38 or more). ) And the like. The mixing ratio of the above monoester is
5 to 50 relative to 100 parts by weight of the polyolefin resin
It is preferably in parts by weight. Further, for the above purpose and the purpose of improving the appearance of the sheet, a mixture of a hydrocarbon polymer having a side chain and a polyester can be used. As the above-mentioned hydrocarbon polymer having a side chain, polyα-olefins having an oligomer region having a side chain having 4 or more carbon atoms are preferable. In addition, ethylene-propylene copolymers such as Lucant or a maleic acid derivative thereof manufactured by Mitsui Petrochemical Industry Co., Ltd., or isobutylene polymers such as polybutene HV manufactured by Idemitsu Petrochemical Industry Co., Ltd. It is also possible to use -100, or an oligomer of butadiene or isoprene, a hydrogenated product thereof, or a derivative derived from these. On the other hand, as the polyester, for example, polyester having a polybasic acid or a polyhydric alcohol as a constituent component is used. Examples of preferable polyesters include castor oil, hydrogenated castor oil, ethylene oxide adduct of hydrogenated castor oil, polyester of glycols and dimer acid, hexaester obtained from trimethylolpropane / dimer acid / stearic acid, trimethylolpropane / Hexaester obtained from adipic acid / stearic acid and the like can be mentioned. The blending weight ratio of the above-mentioned hydrocarbon polymer having a side chain and the above polyester is preferably 3/7 to 7/3, but 1/9 to 10 depending on the desired level of moisture permeability, vertical tear strength, and appearance depending on the application.
You can choose freely within the range of 9/1. The blending ratio of the mixture of the hydrocarbon polymer having a side chain and the polyester is preferably 5 to 50 parts by weight with respect to 100 parts by weight of the polyolefin resin.

As the porous sheet, a) a crystalline polyolefin resin and b) a crystalline polyolefin resin which is miscible with the crystalline polyolefin resin under melting and has a crystallization temperature of the crystalline polyolefin resin. In the following, a porous sheet obtained by forming a sheet from a mixture containing a phase-separated organic compound and stretching the sheet in at least a uniaxial direction can also be preferably used.

As the above crystalline polyolefin resin,
Polypropylene, a blend of polypropylene and a propylene-ethylene copolymer, or a blend of polypropylene and polyethylene can be preferably used.
Further, as the organic compound, mineral oil, synthetic lubricating oil,
Paraffin wax or an ester of an aliphatic carboxylic acid and a polyhydric alcohol can be preferably used.

The crystalline polyolefin resin and the organic compound are preferably compounded in amounts of 50 to 90 parts by weight of the crystalline polyolefin resin and 50 to 10 parts by weight of the organic compound, respectively. It is also preferable to add various additives such as a crystal nucleus forming agent to the porous sheet. The additive is preferably added in an amount of 0.01 to 3 parts by weight based on 100 parts by weight of the mixture of the crystalline polyolefin resin and the organic compound, and 0.0
It is more preferable to add 5 to 1 part by weight.

The stretching ratio at the time of stretching the sheet formed from the mixture containing the crystalline polyolefin resin and the organic compound is preferably 1.
2 to 5 times (area ratio), more preferably 1.2 to 3 times
It is twice.

[(1) -2 Non-moisture permeable sheet] Next, the non-moisture permeable sheet used as the sheet 21 will be described. Regarding the non-moisture permeable sheet, only the points different from the moisture permeable sheet will be described, and as for points that are not particularly described, the detailed description of the moisture permeable sheet will be applied as appropriate. As the non-moisture permeable sheet, a non-moisture permeable and liquid obtained by using a polyolefin resin as a main component, mixing a pigment or a filler with the polyolefin resin and mixing them, and forming a film by a T die molding machine or an inflation molding machine. Examples include general sheets that are impermeable. The non-moisture permeable sheet is preferably based on polyethylene resin and has a basis weight of 1
It is preferably from 0 to 50 g / m ² .

[(2) Nonwoven Fabric] The nonwoven fabric 22 has a fiber diameter of 1.5 to 3.5 denier, preferably 1.5 to 3.0 denier, as described above. More preferably, it is 1.5 to 2.0 denier. If the fiber diameter is less than 1.5 denier, the nonwoven fabric 2
Although the texture and touch such as the softness in 2 are improved, the production thereof becomes difficult and the cost becomes high.
On the other hand, when the fiber diameter is more than 3.5 denier, the non-woven fabric 22 has poor texture such as softness and touch.

As the fibers constituting the non-woven fabric 22,
If the fiber diameter is within the above range, the type is not particularly limited, and both long fiber continuous filaments and short fiber staple fibers can be used. The type of fiber is not particularly limited, and for example, thermoplastic synthetic fibers such as polyethylene, polypropylene, polyester and polyamide, natural fibers such as cotton, hemp and wool, and regenerated fibers such as rayon and acetate can be used. You can

The nonwoven fabric 22 has a basis weight of 10 to 35 g / m ² , and preferably 15 to 35, as described above.
a g / m ^2, more preferably from 18-25 g / m ^2. If the basis weight is less than 10 g / m ² , the softness and texture of the non-woven fabric 22 and the touch are improved, but (a) the strength is lowered and (b) the texture is deteriorated and the degree of blocking occurs. Becomes large and (c) productivity drops. On the other hand, the basis weight is 35
When it exceeds g / m ² , the softness and texture of the non-woven fabric 22 and the touch are deteriorated.

The nonwoven fabric 22 is not particularly limited in its manufacturing method, and examples of the nonwoven fabric 22 include a suction heat bond method, a spun bond method, a melt blown method, a spun lace method, and a needle punch method using a card machine. It is possible to use those manufactured by the well-known method of. The thickness of the non-woven fabric 22 is not particularly limited, but in terms of texture such as softness and touch, the problem of blocking due to deterioration of texture, and productivity,
0.5g / cm ² 0.1-2mm thickness under load
Is preferable, and 0.3 to 1.0 mm is more preferable.

[(3) Adhesive] As described above, the adhesive 23 contains 20% by weight or more of APAO as its constituent component (based on the total amount of the adhesive 23), preferably 30 to 1
It contains 00% by weight. The adhesive containing 20% by weight or more of APAO has fluidity during coating, and thus penetrates between the fibers of the non-woven fabric 22 and is hard to flow at room temperature after solidification, resulting in less tackiness (stickiness). As a result, the adhesive strength when the sheet 21 and the non-woven fabric 22 are combined is increased, and the occurrence of blocking is effectively prevented.

APAO is used as a base polymer in the above-mentioned adhesive, and as the type thereof, conventionally known ones can be used without particular limitation. For example, as APAO, propylene / ethylene copolymer, propylene / butene-1 copolymer, propylene /
A hexene copolymer etc. can be used. These A
PAO is commercially available, for example, under the trade name of Ubetack manufactured by Ube Lexen Co., Ltd. and Eastflex manufactured by Eastman Kodak Company. Further, a propylene / ethylene / butene-1 terpolymer may be used as the APAO. The terpolymer is commercially available from Hürz under the trade name of Bestplast.

The adhesive 23 may be composed of 100% APAO, but in addition to APAO, it further contains one or more of a tackifier, a softening agent and an antioxidant as its constituent components. Good. As the above-mentioned tackifier, those which are solid at room temperature can be preferably used, and examples thereof include C5 petroleum resin, C9 petroleum resin, dicyclopentadiene petroleum resin, rosin petroleum resin, polyterpene resin, terpene phenol resin and the like. Is mentioned. Specific examples include hydrogenated terpene resins such as "Clearon" (trade name, manufactured by Yasuhara Chemical) and hydrogenated aromatic petroleum resins such as "Alcon" (trade name, manufactured by Arakawa Chemical). The compounding amount of the tackifier can be appropriately selected according to the compounding amount of the softening agent, but is usually 30 to 7 relative to the total amount of the adhesive.
It is selected from the range of 0% by weight. Examples of the softener component include a process oil having a softening point of 10 ° C. or lower and an average molecular weight of 200 to 700, mineral oil, various plasticizers,
Preference is given to polybutene, liquid tackifying resins and the like. Specifically, paraffin oils such as "Shelf Rex" (trade name, manufactured by Shell Chemical Co., Ltd.) and "PW-90" (trade name, manufactured by Idemitsu Kosan Co., Ltd.), tetraoctylpyromellitate, di-dodecyl phthalate and trioctyl trihydrate. Examples include ester oils such as melitate. The compounding amount of the softening agent is preferably 20% by weight or less based on the total amount of the adhesive. If the blending amount exceeds 20% by weight, the tackiness (stickiness) of the adhesive is increased, which may cause blocking between the composite sheets 20. Examples of the above-mentioned antioxidant include "Irganox 1010" [trade name, manufactured by Ciba-Geigy Co., Ltd.], "Irganox 1076" [trade name,
Ciba-Geigy Co., Ltd.] or "Sumilyzer GM"
[Trade name, manufactured by Sumitomo Chemical Co., Ltd.] and the like are preferable. The compounding amount of the above antioxidant is preferably 1 to 3 parts by weight with respect to 100 parts by weight of APAO. In addition to the above-mentioned components, the adhesive 23 may contain other components as required.

As described above, the adhesive 23 has a melt viscosity at 180 ° C. of 500 to 10,000 cps, preferably 1,000 to 8,000 cps, and more preferably 1,000 to 6,000 cps. is there. If the melt viscosity is less than 500 cps, the coating amount may be uneven in the width direction, or the adhesive 23 may drop. On the other hand, if it exceeds 10,000 cps, the coating property of the adhesive 23 may be deteriorated to cause unevenness on the coated surface, or the adhesive 23 may drop.

As described above, the adhesive 23 has a coating amount of 0.5 to 7 g / m ² , preferably 0.5 to 5 g.
/ M ^2, still more preferably from 0.5 to 3 g / m ^2. If the coating amount is less than 0.5 g / m ² , the adhesive strength between the sheet 21 and the non-woven fabric 22 is insufficient, and if it exceeds 5 g / m ² , the adhesive strength is sufficient, but The texture of the composite sheets 20 deteriorates, and blocking occurs between the composite sheets 20.

The adhesive 23 may be applied over the entire surface between the sheet 21 and the non-woven fabric 22 as shown in FIG. 1, but in terms of texture or the sheet 21 is a moisture permeable sheet. In this case, it is preferable to apply the resin intermittently from the viewpoint of maintaining the moisture permeability. Examples of the intermittent coating method include linear, dot, rectangular, and spiral shapes. When the adhesive 23 is applied intermittently, the adhesive area ratio is 20 within the range of the above-mentioned coating amount.
It is preferable that the coating be performed so that the amount becomes 60%. As a method for applying the adhesive 23, a so-called slot spray method, curtain spray method and meltblown method, spiral spray method, gravure method, and the above adhesive which apply the adhesive 23 in a mist form There is a method of applying 23 in a linear shape.

The composite sheet 20 shown in FIG. 1 is subjected to a predetermined joining means, for example, hot embossing or heat roll processing, particularly heat embossing, after the sheet 21 and the non-woven fabric 22 are bonded by the adhesive. Is preferred. That is, the composite sheet 20 is the sheet 21
It is particularly preferable that the non-woven fabric 22 and the non-woven fabric 22 are joined by the adhesive 23 and hot embossing.
By the heat embossing, the texture and flexibility can be improved, or the touch of the composite sheet 20 and the adhesive strength between the sheet 21 and the nonwoven fabric 22 can be further improved. In addition, the sheet 21 and the nonwoven fabric 2
It is also possible to effectively prevent the wrinkles of the composite sheet 20 from shrinking due to the difference in the tension (extension rate) at the time of laminating with 2. The embossed area ratio of the composite sheet 20 due to the hot embossing is preferably 40% or less of the total area of the composite sheet 20. 1
It is more preferably 0 to 30%. When the embossed area ratio exceeds 40%, the composite sheet 20 becomes hard and the texture such as softness decreases, or the composite sheet 20.
The moisture permeability of may decrease. The details of the conditions for the hot embossing will be described later.

In the composite sheet 20 shown in FIG. 1, the above-mentioned sheet 21 and the above-mentioned non-woven fabric 22 are joined by the above-mentioned adhesive, so that the adhesive strength between the sheet 21 and the non-woven fabric 22 is high, and moreover, blocking is achieved. Is effectively prevented. Specifically, the adhesive strength between the sheet 21 and the nonwoven fabric 22 in the composite sheet 20 is preferably 30 g / 25 mm or more, and more preferably 50 g /
25 mm or more, more preferably 100 g / 25 m
m or more. There is no particular upper limit to the adhesive strength, and the higher the better, the better. The blocking strength of the composite sheet is preferably 20 g / 50 mm or less, more preferably 15 g / 50 mm or less, and further preferably 10 g / 50 mm or less. The lower limit of the blocking strength is not particularly limited, and the lower the lower the better. The method for measuring the adhesive strength and the blocking strength will be described in detail in Examples described later.

Next, a preferred embodiment of the absorbent article of the present invention using the composite sheet 21 shown in FIG. 1 will be described with reference to FIG. Here, FIG. 2 is a perspective view showing a disposable diaper as a preferred embodiment of the absorbent article of the present invention.

The disposable diaper 1 of the embodiment shown in FIG.
Is a liquid permeable front material 2, a liquid impermeable back material 3,
An absorbent body (not shown) interposed therebetween is provided, and the front surface material 2 and the back surface material 3 and the first elastic material interposed therebetween are provided in the abdominal waist portion 5 and the back waist portion 5 ′. Waist gathers 7 and 7 ', which are composed of the member 6, are provided. The abdominal waist portion 5 and the back waist portion 5 ′ are arranged so as to be located around the front and rear end portions of the absorbent body.

Leg gathers 9 and 9'consisting of the front surface material 2, the back surface material 3 and the second elastic member 8 interposed therebetween are formed at the leg portions on both sides in the longitudinal direction of the diaper 1. Has been done.

Fastening tapes 10 for fastening the abdominal waist portion 5 and the back waist portion 5'when the diaper 1 is attached to both sides in the width direction of the back waist portion 5'of the diaper 1. 10 'are provided. Further, a landing tape 11 as an adhered portion of the fastening tapes 10 and 10 'is arranged on the surface of the back surface material 3 in the ventral waist portion 5 of the diaper 1.
The fastening tapes 10 and 10 ′ are configured to be fixed to the landing tape 11.

The above-mentioned absorber has a portion corresponding to the crotch portion of the diaper entangled, and is curved in an hourglass shape. Then, in the abdominal waist portion 5 and the dorsal waist portion 5 ′ and the left and right leg portions located around the absorber, the first elastic member 6 and the second elastic member 8 are the surface material 2 and the back surface, respectively. It is stretched between the material 3 and
The first elastic member 6 and the second elastic member 8 contract in a free state to form waist gathers 7 and 7'and leg gathers 9 and 9'as shown in FIG. It is designed to fit your crotch.

Each member constituting the diaper 1 will be described. The surface material 2 is preferably a liquid permeable sheet that allows excrement to pass through to the absorbent body, and has a feeling close to that of underwear. As such a liquid permeable sheet, for example, a woven fabric, a nonwoven fabric, a porous film and the like are preferably mentioned. Further, a method of applying a hydrophobic compound such as a silicone oil or paraffin wax to the peripheral edge of the surface material 2, or a method of previously applying a hydrophilic compound such as an alkyl phosphate ester to the entire surface and washing the peripheral edge with warm water. It is also possible to preferably use a material in which the peripheral portion of the surface material 2 is subjected to a water repellent treatment so as to prevent the peripheral portion from leaking due to bleeding of urine or the like.

As the absorbent body interposed between the surface material 2 and the back surface material 3, a defibrated pulp as a main material and a high-molecular water-absorbing polymer in combination, a thermoplastic resin, a cellulose fiber, and It is preferable to use a mixture of high-molecular water-absorbing polymers that has been heat-treated. Also,
A mixture of a high-molecular water-absorbing polymer and pulp may be used. In this case, the polymer water-absorbing polymer may be present in any of the upper layer, the middle layer and the lower layer of the absorber. As the above-mentioned high molecular weight water-absorbing polymer, a particulate polymer having a retaining property capable of absorbing and retaining a liquid of 20 times or more its own weight and having a gelling property is preferable. Examples of such high-molecular water-absorbing polymers include starch-acrylic acid (salt) graft copolymers, saponified starch-acrylonitrile copolymers, sodium carboxymethylcellulose cross-linked products, acrylic acid (salt) polymers. And the like are preferable.

As the first elastic member 6 for the waist gathers 7 and 7'and the second elastic member 8 for the leg gathers 9 and 9 ', thread rubber, flat rubber, film type rubber or film-like foam. Polyurethane or the like is preferably used.

In the disposable diaper 1 of the embodiment shown in FIG. 2, the composite sheet is used as the back sheet. In the disposable diaper 1, the nonwoven fabric 22 side of the composite sheet 20 is used so as to face the outside of the disposable diaper 1. As a result, the disposable diaper has the non-woven fabric 2
Due to the cloth-like texture of No. 2, the texture such as softness and the touch are improved. Moreover, when a moisture permeable sheet is used as the sheet 21 in the composite sheet 20, steam inside the diaper is released to the outside through the moisture permeable sheet, so that the stuffiness inside the diaper and the wearer accompanying it Skin irritation is prevented.

Although the composite sheet and the absorbent article of the present invention have been described above based on the preferred embodiments thereof, the present invention is not limited to the above embodiments and includes various modifications. . For example, in the composite sheet 20 of the embodiment shown in FIG. 1, the nonwoven fabric 2 is formed on the other surface of the sheet 21 that is joined to the nonwoven fabric 22.
Nonwoven fabrics of the same type or different types as those of No. 2 or other sheets may be joined to form a composite sheet having a three-layer structure. Moreover, in the composite sheet 20 of the embodiment shown in FIG.
The sheet 21 and the non-woven fabric 22 may have the same size or different sizes. In addition, the non-woven fabric is 22
It may be continuously laminated on the sheet 21 or may be discontinuously laminated. The composite sheet can also be used for applications such as waterproof clothing, waterproof covers, and packaging materials that require touch, feel and waterproofness, and particularly applications where moisture permeability is required.

Although the embodiment shown in FIG. 2 is a deployable disposable diaper, the absorbent article of the present invention can be similarly applied to a pants-type disposable diaper. Further, the absorbent article of the present invention is not limited to disposable diapers, but can be similarly applied to sanitary napkins, incontinence pads and the like.

Next, a preferred method for manufacturing the disposable diaper of the embodiment shown in FIG. 2 will be described with reference to the drawings. Here, FIG. 3 is a schematic view showing an apparatus used in a preferable method for manufacturing the disposable diaper of the embodiment shown in FIG.

In the disposable diaper 1 shown in FIG. 2,
The composite sheet 20 as the backing material 3 is obtained by applying the adhesive 23 having the above-mentioned physical properties to the above-mentioned sheet 21 having the above-mentioned physical properties in the above-mentioned coating amount and applying the above-mentioned physical properties onto the coated surface. It is preferably manufactured by pasting the above-mentioned non-woven fabric 22 having the above and then performing hot embossing and joining. The term "hot embossing" used herein means a case where the composite sheet is preheated and then embossed,
Both when embossing the composite sheet with heated embossing.

The above-mentioned manufacturing method will be described in more detail with reference to FIG. 3. The melt-blown coating machine 33 is provided on one surface of the sheet 21 unwound from the sheet winding 31.
Is used to spray the adhesive 23 in a mist state, and a dot-shaped coating pattern is applied in the above-described coating amount. Then, the non-woven fabric 22 unwound from the non-woven fabric winding 32,
By sticking the composite sheet on the coated surface to form a composite sheet and inserting the composite sheet between the pair of nip rolls 34, 34, the adhesion between the sheet 21 and the nonwoven fabric 22 is ensured. Subsequently, the composite sheet is inserted between a pair of embossing rolls 35, 35 to perform hot embossing. The composite sheet 20 thus obtained is wound by a winder (not shown). In this case, instead of the embossing rolls 35, 35, a space between heat rolls may be inserted to enhance the adhesive strength. The wound-up composite sheet is unwound and used in a usual process for producing a disposable diaper to produce the disposable diaper shown in FIG.

As the embossing roll, a pair of rolls generally composed of an engraving roll and a smooth roll can be used. As the engraving roll, for example, an iron roll having various patterns engraved on its surface can be used. On the other hand, as the smooth roll, a paper roll, a rubber roll, a silicon rubber roll, a urethane rubber roll, a metal roll, or the like can be used. In the apparatus shown in FIG. 3, hot embossing is performed by heating and using one or both of these rolls. The heating temperature of the embossing roll is preferably 10 ° C. or more lower than the melting point of the sheet 21 or the nonwoven fabric 22 that is in direct contact with the heated embossing roll. When the embossing roll is heated to a temperature higher than this, the composite sheet may adhere to the embossing roll, the composite sheet may shrink due to heat, or wrinkles may occur. Also,
When both rolls are heated, heat embossing may be performed with a temperature difference (for example, 10 to 30 ° C.) between the engraving roll and the smooth roll to improve the texture and flexibility of the resulting composite sheet. It is preferable in terms. In this case, the heating temperature of the engraving roll is preferably higher than the heating temperature of the smooth roll. Examples of the pattern of the engraving roll include, for example, pins, dot dots, turtle shells, lattices, vertical stripes, horizontal stripes, stitches, and patterns, and are not particularly limited to the patterns. The linear pressure of the embossing roll during the hot embossing depends on the thickness and running speed of the composite sheet to be hot embossed, the heating temperature of the embossing roll, etc., but is generally 10 to 150 kg / c.
m is preferable.

The description of the conventional method for producing a disposable diaper can be applied to the points not particularly described in detail regarding the method for producing a disposable diaper.

[0057]

EXAMPLES The effectiveness of the composite sheet and absorbent article of the present invention will be illustrated below with examples. However, such examples do not limit the scope of the invention in any way.

Example 1 Linear low-density polyethylene [Ultzex 2520F, manufactured by Mitsui Petrochemical Industry Co., Ltd.]
To 100 parts by weight and 150 parts by weight of surface-treated calcium carbonate (average particle size; 1 μm), 10 parts by weight of an ester having the composition and physical property values shown in Table 1 were added, and the mixture was kneaded with a twin-screw kneader to form pellets. It was made. The obtained pellets are supplied to an inflation molding machine and the thickness is 40 μm.
Inflation sheet was molded. The obtained sheet is stretched at a stretching temperature of 50 ° C. using a roll stretching machine and a stretching ratio of 2.
It was stretched 3 times to obtain a porous moisture permeable sheet. The moisture permeable sheet has a thickness of 20 μm and a moisture permeability of 1.8 g / (1
00 cm ² · h) and the basis weight was 20 g / m ² .

[0059]

[Table 1]

Using the apparatus shown in FIG. 3, the adhesive having the composition shown in Table 2 was melt-blown (hot air temperature 190 ° C., pressure 1.8 kg / c) on the moisture-permeable sheet.
m ² ) was applied in spots (coating amount 1.0 g / m ² , coating temperature 170 ° C., coating speed 200 m / min). A suction heat-bonded nonwoven fabric having a fiber diameter of 1.5 denier, a basis weight of 22 g / m ² , and a thickness of 0.5 mm under a load of 0.5 g / cm ² is applied on the coating surface. Combined into a composite sheet. About the obtained composite sheet, 2 by the following method
The adhesive strength in a width of 5 mm and the blocking strength in a width of 50 mm were measured. Table 3 shows the results. Moreover, the disposable diaper shown in FIG. 2 was produced using the obtained composite sheet. During production of the diaper, blocking of the composite sheet was not observed, and tearing of the composite sheet or entanglement with a roll did not occur. Further, the obtained disposable diaper had stuffiness prevented and improved texture such as softness and touch.

<Method of measuring adhesive strength> From the composite sheet,
A test piece having a width of 25 mm along the MD direction of the composite sheet and a length of 100 mm along the CD direction of the composite sheet was cut out. Using a Tensilon tensile tester, the test piece was peeled at 180 ° in the CD direction (with a tensile speed of 300).
mm / mim, measurement temperature 20 ° C.) to measure the adhesive strength. <Method of measuring blocking strength> A composite sheet is wound around a paper tube for about 1000 m to be in a roll state, and stored in an atmosphere of 50 ° C for 1 week. After the storage, a sufficient cooling time is allowed, and the composite sheet is placed in a state where two composite sheets are overlapped on a portion 30 mm radially outward from the paper tube in a state where the composite sheet is overlapped.
A piece having a width of 50 mm and a length of 100 mm along the MD direction of the composite sheet is cut out along the D direction to obtain a test piece. For this test piece, a 180 ° peel test (tensile speed 500
m / min, measurement temperature 20 ° C.) to measure the blocking strength.

[Examples 2 to 6] Example 1 except that the adhesive was applied under the conditions shown in Table 3 and hot embossing was performed at the embossed area ratio shown in Table 3 (Examples 4 to 6). A composite sheet was obtained by the same operation. The same measurement as in Example 1 was performed on the obtained composite sheet. Table 3 shows the results. The hot embossing conditions were a heating temperature of the embossing roll of 90 ° C. and a linear pressure of 60 kg / cm. Also,
The disposable diapers shown in FIG. 2 were produced using the obtained composite sheets. During production of the diaper, blocking of the composite sheet was not observed, and tearing of the composite sheet or entanglement with a roll did not occur. Further, the obtained disposable diaper had stuffiness prevented and improved texture such as softness and touch.

Comparative Example 1 A composite sheet was obtained in the same manner as in Example 1 except that SIS hot melt (conventional product) was used instead of the adhesive in Example 1. The same measurement as in Example 1 was performed on the obtained composite sheet. Table 3 shows the results. When the disposable diaper shown in FIG. 2 was produced using the obtained composite sheet, tearing and entanglement with the roll due to blocking of the composite sheet occurred during production of the diaper.

[0064]

[Table 2]

[0065]

[Table 3]

As is clear from the results shown in Table 3, the composite sheet of the present invention in which a sheet having specific physical properties and a nonwoven fabric having specific physical properties are joined with an adhesive having specific physical properties (Example 1) Nos. 6 to 6) have a higher adhesive strength and a lower blocking strength (that is, blocking is less likely to occur) than the composite sheet (Comparative Example 1) obtained by using a conventional hot melt. I understand.
In particular, a composite sheet obtained by laminating the moisture permeable sheet and the non-woven fabric and then hot embossing (Example 4)
In ~ 6), the adhesive strength was extremely high.

[Examples 7 to 12] Low density polyethylene [Ultox 2080 manufactured by Mitsui Petrochemical Industry Co., Ltd.]
(Brand name)] 5 parts by weight of titanium oxide was added to 100 parts by weight and kneaded with a twin screw type kneader to prepare pellets. The obtained pellets were supplied to a T-die molding machine to obtain a moisture-impermeable sheet having a thickness of 20 μm. Using the obtained non-moisture permeable sheet, the same adhesive as in Example 1 was applied under the conditions shown in Table 4, and hot embossing was performed at the embossed area ratio shown in Table 4 (Examples 10 to 12). A composite sheet was obtained by the same operation as in Example 1 except for the above. The same measurement as in Example 1 was performed on the obtained composite sheet. The results are shown in Table 4. The conditions for hot embossing are as follows:
It was similar to 6. Moreover, the disposable diaper shown in FIG. 2 was each produced using the obtained composite sheet. During production of the diaper, blocking of the composite sheet was not observed, and tearing of the composite sheet or entanglement with a roll did not occur.

[0068]

[Table 4]

As is clear from the results shown in Table 4, the composite sheet of the present invention (Example 7) in which a sheet having specific physical properties and a nonwoven fabric having specific physical properties are joined by an adhesive having specific physical properties (Example 7) It can be seen that Nos. 12 to 12) have high adhesive strength and low blocking strength (that is, blocking is less likely to occur). Particularly, in the composite sheets (Examples 10 to 12) obtained by hot embossing after the non-moisture permeable sheet and the non-woven fabric were bonded together, the adhesive strength was extremely high.

[0070]

According to the present invention, a composite sheet having a high adhesive strength and preventing the occurrence of blocking can be obtained. Therefore, when an absorbent article is manufactured using the composite sheet of the present invention, breakage of the composite sheet and entanglement with a roll during manufacturing can be effectively prevented. Further, according to the absorbent article of the present invention, stuffiness is prevented and the texture such as softness and the touch are improved. Further, according to the method for manufacturing an absorbent article of the present invention, unwinding trouble due to occurrence of blocking is effectively prevented.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing the structure of a preferred embodiment of a composite sheet of the present invention.

FIG. 2 is a perspective view showing a disposable diaper as a preferred embodiment of the absorbent article of the present invention.

FIG. 3 is a schematic view showing an apparatus used in a preferable method for manufacturing the disposable diaper of the embodiment shown in FIG.

[Explanation of symbols]

 20 Composite Sheet 21 Sheet 22 Nonwoven Fabric 23 Adhesive

Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location B32B 27/00 C09J 201/00 JAP 27/12 D06C 23/04 B C09J 201/00 JAP A41B 13/02 F D06C 23/04 A61F 13/18 320 // D06M 17/00 D06M 17/00 K (72) Inventor Kazuo Fujita 2606 Akabane, Kaicho, Haga-gun, Tochigi Prefecture Kao Corporation Stock Research Institute

Claims (10)

[Claims] 1. A composite sheet obtained by joining a sheet and a non-woven fabric with an adhesive, wherein the sheet is a liquid impermeable sheet having a thickness of 15 to 40 μm, and the non-woven fabric has a fiber diameter of 1.5 to 3.5 denier, the basis weight is 10 to 35 g / m ² , and the adhesive contains 20% by weight or more of amorphous polyalphaolefin (APAO) as its constituent component,
Its melt viscosity at 180 ° C is 500-10,000 cps
And the coating amount thereof is 0.5 to 7 g / m ² . 2. The sheet according to claim 1, wherein the sheet has moisture permeability and the amount of moisture permeability is 0.5 to 4 g / (100 cm ² · h).
The composite sheet as described. 3. The composite sheet according to claim 1, wherein the adhesive further contains one or more of a tackifier, a softening agent and an antioxidant. 4. The melt viscosity of the adhesive is 180 ° C.
The composite sheet according to claim 1, wherein the composite sheet has a viscosity of 1,000 to 8,000 cps. 5. The composite sheet according to claim 1, wherein the composite sheet is heat-embossed. 6. The composite sheet according to claim 5, wherein the embossed area ratio by the hot embossing is 40% or less of the total area of the composite sheet. 7. The adhesive strength between the sheet and the non-woven fabric in the composite sheet is 30 g / 25 mm or more,
Blocking strength of the above composite sheet is 20 g / 50 mm
The composite sheet according to claim 1, wherein: 8. An absorbent article comprising a liquid-permeable front material, a liquid-impermeable back material, and an absorber interposed between the front material and the back material, wherein the back material is claimed as the back material. Item 2. An absorbent article using the composite sheet according to item 1. 9. A method for manufacturing an absorbent article, which uses a composite sheet obtained by joining a sheet and a nonwoven fabric with an adhesive as a backing material, wherein the sheet is a liquid impermeable sheet having a thickness of 15 to 40 μm, The non-woven fabric has a fiber diameter of 1.5 to 3.0 denier and a basis weight of 10 to 35 g / m ² , and the adhesive has 20 parts of amorphous polyalphaolefin (APAO) as its constituent component. The melt viscosity is 500% to 10,000c at 180 ° C.
ps, the coating amount is 0.5 to 7 g / m ² ,
Then, the adhesive is applied onto the sheet, the non-woven fabric is pasted onto the coated surface, and then the sheet and the non-woven fabric are joined by a predetermined joining means. . 10. A method for producing a composite sheet, which comprises a sheet and a nonwoven fabric bonded with an adhesive, wherein the sheet is a liquid impermeable sheet having a thickness of 15 to 40 μm, and the nonwoven fabric has a fiber diameter of 1 or less. 0.5 to 3.0 denier, the basis weight is 10 to 35 g / m ² , and the adhesive contains 20% by weight or more of amorphous polyalphaolefin (APAO) as its constituent component and has a melt viscosity. 500 to 10,000c at 180 ° C
ps, the coating amount is 0.5 to 7 g / m ² ,
A method for producing a composite sheet, which comprises applying the adhesive to the sheet, bonding the non-woven fabric to the coated surface, and then joining the sheet and the non-woven fabric by a predetermined joining means.