JP3311955B2 - Composite sheet and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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 producing 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 feel, a back permeable material and a nonwoven fabric are used as an outermost layer, and SIS (styrene-isoprene- Styrene) and SB
Composite sheets joined by a so-called rubber-based hot melt adhesive based on S (styrene-butadiene-styrene) or a mixture thereof are used.

In the case of manufacturing a disposable diaper using the composite sheet, for example, it is general to manufacture the disposable diaper while unwinding the roll-shaped composite sheet. In this case, in consideration of the texture and feel of softness and the like in the disposable diaper, when a thin and coarse non-woven fabric is used as the non-woven fabric in the composite sheet, the roll pressure of the composite sheet during the roll state of the composite sheet causes The adhesive oozes out on the surface of the nonwoven 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 a state where blocking has occurred, the composite sheet is torn or entangled with the roll without unwinding.

On the other hand, if the coating amount of the adhesive is reduced to avoid the problem of occurrence of blocking, the adhesive strength between the moisture-permeable sheet and the nonwoven fabric is reduced, and the back material of an absorbent article such as a disposable diaper is reduced. Would be unsuitable for

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

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a composite sheet in which a sheet having specific physical properties and a non-woven fabric having specific physical properties are joined by an adhesive having specific physical properties is obtained. It has been found that the purpose can be achieved.

The present invention has been made based on the above findings. In a composite sheet in which a sheet and a nonwoven fabric are bonded by an adhesive, the sheet has a thickness of 15 to 40 μm.
m, a liquid-impermeable sheet having a fiber diameter of 1.5 to 3.5 denier and a basis weight of 10 to 3.5 denier.
35 g / m ² , and the adhesive used as the base polymer was amorphous polyalphaolefin (AP
AO) in an amount of at least 20% by weight and a melt viscosity of 180
℃ In a 500～10,000Cps, the coating amount 0.5 to 5 g / m are ^two der, is wound into a roll state
Is obtained by achieving the above objects by providing a have composite sheet, characterized in Rukoto.

[0008]

[0009]

The present invention also relates to a method for producing a composite sheet in which a sheet and a nonwoven fabric are joined by an adhesive, wherein the sheet is a liquid-impermeable sheet having a thickness of 15 to 40 μm, Fiber diameter is 1.5-3.
0 denier, the basis weight is 10 to 35 g / m ² , the adhesive contains 20% by weight or more of amorphous polyalphaolefin (APAO) as a base polymer, and its melt viscosity is 500 to 500 ° C at 180 ° C. 10,000
0 cps, the coating amount is 0.5 to 5 g / m ² , and the adhesive is coated on the sheet, and the nonwoven fabric is bonded on the coated surface. The sheet and the nonwoven fabric are joined and then rolled
Take-there is provided a method of manufacturing a composite sheet according to claim Rukoto.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 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 nonwoven 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. - non-woven fabric 22, the fiber diameter of 1.5 to 3.5 deniers, a basis weight of 15 to 35 g / m ^2. The adhesive 23 has an amorphous polyalphaolefin (hereinafter referred to as “APAO”) as a constituent component thereof.
At a melting viscosity of 180 ° C.
00 to 10,000 cps and the coating amount is 0.5
７7 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 thickness is preferably used. As the sheet 21, any of a moisture permeable sheet and a non-moisture permeable sheet can be used. Among these sheets, the moisture permeable sheet easily emits water vapor, so if the composite sheet 20 having the moisture permeable sheet is used as a back sheet of a disposable diaper as described later, the moisture inside the diaper and the wear of the wearer associated therewith are reduced. Skin irritation is effectively prevented. Hereinafter, these moisture permeable sheets and non-moisture permeable sheets will be described respectively.

[(1) -1 Moisture permeable sheet] The above sheet 2
The moisture permeable sheet used as 1 preferably has a moisture permeability of 0.5 to 4 g / (100 cm ² · h), more preferably 1.0 to 2.5 g / (100 cm ^2.
H) is used. The moisture permeability is 0.5 g
If it is less than / (100 cm ² · h), when the composite sheet 20 is used as a back sheet of an absorbent article such as a disposable diaper as described later, the inside of the diaper and the accompanying skin irritation of the wearer are not affected. It cannot be sufficiently prevented, and if it exceeds 4 g / (100 cm ² · h), leakage of liquid such as urine is concerned. In addition, the above-mentioned moisture permeability is JIS
It is a value measured according to Z0208.

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

The basis weight of the moisture-permeable sheet is not particularly limited, but is preferably 15 to 40 g / m ² from the viewpoint of difficulty in controlling the thickness at the time of production and the feeling and texture, 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, a resin mainly containing a monoolefin polymer and a copolymer such as ethylene, propylene and butene is used.
For example, as the polyolefin resin, 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. Inorganic fillers include 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 Preferred are magnesium, calcium oxide, magnesium oxide, titanium oxide, alumina, mica, asbestos powder, shirasu balloon, zeolite, silicate clay, cement, silica fume, mica powder and the like. On the other hand, as the organic filler, wood powder, coal powder, pulp powder and the like are 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, and most preferably 0.5 μm to 5 μm. The filler is preferably surface-treated from the viewpoint of uniform dispersibility in the polyolefin resin. What can hydrophobize a surface, such as a fatty acid or its metal salt, is preferably used for this surface treatment. The mixing ratio of the filler is preferably 50 to 250 parts by weight based on 100 parts by weight of the polyolefin resin.

Various third components can be added to the polyolefin resin for the purpose of improving various performances of the porous sheet. For example, in order to improve the tear strength in the stretching direction and the tensile stress in the transverse direction of the porous sheet, an olefin-based low-melting polymer, a liquid or waxy hydrocarbon polymer, a rubbery substance (for example, natural rubber, isoprene) Rubber, butadiene rubber), an olefin-based thermoplastic elastomer, a styrene-based thermoplastic elastomer, or a plasticizer.

For the purpose of improving the sheet strength of the porous sheet and forming continuous holes in the porous sheet even at a low stretching ratio, triglyceride is preferably added to 100 parts by weight of the polyolefin resin. -100 parts by weight can be blended. The fatty acid constituting the triglyceride is preferably a saturated or unsaturated fatty acid having 2 to 30 carbon atoms. For the same purpose,
Chlorinated paraffins can also be used as the third component.
In this case, the chlorine content is preferably 1 to 65% by weight.
Of paraffin chloride, more preferably 35 to 55% of paraffin chloride. Such chlorinated paraffins
It is manufactured by a known method, for example, by passing chlorine gas through a solution of molten solid paraffin, n-paraffin or solid paraffin in carbon tetrachloride. The proportion of the chlorinated paraffin is 1 to 100 parts by weight of the 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 monoester include an ester obtained by dehydration condensation from a monobasic acid such as a monocarboxylic acid having 10 or more carbon atoms and a monohydric alcohol such as a monoalcohol having 10 or more carbon atoms, but preferably, Monoesters having a molecular weight of 240 or more, more preferably monoesters having a carbon number of 20 or more and containing a branched hydrocarbon chain are used. On the other hand, as the polyester, for example, dicarboxylic acids, polybasic acids such as tricarboxylic acids or tetracarboxylic acids and diols, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol or polyhydric alcohols such as sucrose Examples of the polyester obtained by dehydration condensation include those having 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 based on 100 parts by weight of the polyolefin resin. The monoester contributes to the improvement of the moisture permeability and the vertical tear strength of the obtained porous sheet, and the polyester contributes to the improvement of the moisture permeability and the appearance. Furthermore, for the same purpose, it is possible to use a mixture of a polyester A comprising a polybasic acid and a monohydric alcohol and a polyester B comprising a polybasic acid and a polyhydric alcohol. The polyester A is, for example, a diester, a triester or a tetraester obtained by dehydrating and condensing a polybasic acid such as dicarboxylic acid, tricarboxylic acid or tetracarboxylic acid with a monohydric alcohol and having a total carbon number of 30. The above are 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, as the polyester B, 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, From a polyester obtained by dehydration condensation and having a total carbon number of 50
The above are 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 tearing strength while maintaining a supple feel and good moisture permeability and leakproofness of the porous sheet, the porous sheet is a monoester having a total carbon number of 38 or more. Those in which at least one of the acid and alcohol constituting the ester is branched can be used. Specific examples of monoesters include 2-decyltetradecylstearate, 2-octadecylbehenate, and esters of α-branched fatty acids (C18 to C40) with monoalcohols (C6 to C36) (total carbon number of 38 or more) ) And the like. The mixing ratio of the above monoester,
5 to 50 with respect to 100 parts by weight of the polyolefin resin
It is preferably in parts by weight. In addition, a mixture of a hydrocarbon polymer having a side chain and a polyester can be used for the above purpose and for the purpose of improving the sheet appearance. The hydrocarbon polymer having a side chain is preferably a poly-α-olefin having an oligomer region having a side chain having 4 or more carbon atoms. In addition, copolymers of ethylene and propylene, such as Lucant and its maleic acid derivative manufactured by Mitsui Petrochemical Industry Co., Ltd., and polymers of isobutylene, such as Polybutene HV manufactured by Idemitsu Petrochemical Industry Co., Ltd. It is also possible to use an oligomer of -100 or butadiene or isoprene and a hydrogenated product thereof, or a derivative derived therefrom. On the other hand, as the polyester, for example, a polyester containing a polybasic acid or a polyhydric alcohol as a component is used. Examples of preferred 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 compounding weight ratio of the hydrocarbon polymer having a side chain to the polyester is preferably 3/7 to 7/3, but 1/9 to 7/9 depending on the desired level of moisture permeability, vertical tear strength, and appearance according to the application.
It can be freely selected in the range of 9/1. The mixing ratio of the mixture of the hydrocarbon polymer having a side chain and the polyester is preferably 5 to 50 parts by weight based on 100 parts by weight of the polyolefin resin.

Further, as the porous sheet, a) a crystalline polyolefin resin; and b) a crystallization temperature of the crystalline polyolefin resin which is miscible with the crystalline polyolefin resin while the crystalline polyolefin resin is molten. In the following, a porous sheet obtained by forming a sheet from a mixture containing an organic compound that undergoes phase separation and stretching the sheet in at least one axial direction can also be preferably used.

The crystalline polyolefin resin includes:
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 amounts of the crystalline polyolefin resin and the organic compound are preferably 50 to 90 parts by weight of the crystalline polyolefin resin and 50 to 10 parts by weight of the organic compound. It is also preferable to add various additives such as a crystal nucleating agent to the porous sheet. The additive is preferably incorporated 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.
More preferably, 5 to 1 part by weight is blended.

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

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

[(2) Non-woven fabric] The non-woven 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 feel such as softness and the like in 2 are improved, the production becomes difficult and the cost is increased.
On the other hand, if the fiber diameter exceeds 3.5 denier, the texture and feel of the nonwoven fabric 22 such as softness become poor.

The fibers constituting the nonwoven fabric 22 include:
There are no particular restrictions on the type of fiber as long as the fiber diameter is within the above range, and either long fiber continuous filaments or short fiber staple fibers can be used. There is no particular limitation on the type of fiber. For example, thermoplastic synthetic fibers such as polyethylene, polypropylene, polyester and polyamide, natural fibers such as cotton, hemp and wool, and recycled fibers such as rayon and acetate are used. Can be.

The nonwoven fabric 22 has a basis weight of 10 to 35 g / m ^{2 as} described above, preferably 15 to 35 g / m ^2.
a g / m ^2, more preferably from 18-25 g / m ^2. When the grammage is less than 10 g / m ² , the texture and feel such as softness of the nonwoven fabric 22 are improved, but (a) the strength is reduced, and (b) the texture is deteriorated and the degree of occurrence of blocking is caused. And (c) the productivity decreases. On the other hand, when the grammage is 35
If it exceeds g / m ² , the texture and feel of the nonwoven fabric 22 such as softness and the like become poor.

The method of producing the nonwoven fabric 22 is not particularly limited. Examples of the nonwoven fabric 22 include a suction heat bonding method using a card machine, a spun bonding method, a melt blown method, a spunlace method, and a needle punching method. Can be used. In addition, the nonwoven fabric 22 is not particularly limited in its thickness, but in terms of texture and touch such as softness, a problem of occurrence of blocking due to deterioration of formation, and productivity,
The thickness under a load of 0.5 g / cm ² is 0.1 to ² mm
Is preferably, and more preferably, 0.3 to 1.0 mm.

[(3) Adhesive] As described above, the adhesive 23 contains APAO as a constituent component in an amount of 20% by weight or more (based on the total amount of the adhesive 23), preferably 30 to 1%.
It contains 00% by weight. An adhesive containing APAO in an amount of 20% by weight or more has fluidity at the time of coating, so that the adhesive penetrates between the fibers of the nonwoven fabric 22, and hardens to flow at room temperature after solidification, and the tackiness (stickiness) is reduced. As a result, the adhesive strength when the sheet 21 and the nonwoven 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 a conventionally known type can be used without particular limitation. For example, as APAO, propylene / ethylene copolymer, propylene / butene-1 copolymer, propylene /
Hexene copolymers and the like can be used. These A
PAO is commercially available under the trade names of Ube Tac manufactured by Ube Lexen Co., Ltd., and Eastflex manufactured by Eastman Kodak Co., Ltd. Also, a propylene / ethylene / butene-1 terpolymer can be used as the APAO. The terpolymer is commercially available from Hürz under the trade name Bestplast.

The adhesive 23 may be made of 100% APAO, but further contains one or more of a tackifier, a softener and an antioxidant as constituents in addition to APAO. Is also good. As the tackifier, those which are solid at room temperature can be preferably used. For example, C5 petroleum resin, C9 petroleum resin, dicyclopentadiene petroleum resin, rosin petroleum resin, polyterpene resin, terpene phenol resin, etc. 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 based on the total amount of the adhesive.
It is selected from the range of 0% by weight. Examples of the softener component include process oils having a softening point of 10 ° C. or lower and an average molecular weight of 200 to 700, mineral oil, various plasticizers,
Preferable examples include polybutene and a liquid tackifying resin. Specifically, paraffin oils such as "Shellflex" (trade name, manufactured by Shell Chemical), "PW-90" (trade name, manufactured by Idemitsu Kosan), tetraoctyl pyromellitate, di-dodecyl phthalate, and trioctyl tri Ester oils such as melitate and the like can be mentioned. The amount of the softener is preferably 20% by weight or less based on the total amount of the adhesive. When the compounding amount exceeds 20% by weight, the tackiness (stickiness) of the adhesive increases, which may cause blocking between the composite sheets 20. Examples of the antioxidant include “Irganox 1010” (trade name, manufactured by Ciba Geigy Co., Ltd.) and “Irganox 1076” (trade name,
Ciba-Geigy Co., Ltd.] or "Sumilyzer GM"
[Trade name, manufactured by Sumitomo Chemical Co., Ltd.] and the like. The amount of the antioxidant is preferably 1 to 3 parts by weight based on 100 parts by weight of APAO. In addition, in addition to the above components, other components may be added to the adhesive 23 as needed.

As described above, the adhesive 23 has a melt viscosity of 500 to 10,000 cps at 180 ° C., 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 becomes uneven in the width direction, or the adhesive 23 drops. On the other hand, if it exceeds 10,000 cps, there is a possibility that the coatability of the adhesive 23 is reduced and the coated surface becomes uneven or the adhesive 23 drops off.

As described above, the coating amount of the adhesive 23 is 0.5 to 5 g / m ² , preferably 0.5 to 3 g.
A / m ^2. If the coating amount is less than 0.5 g / m ² , the adhesive strength between the sheet 21 and the nonwoven fabric 22 is not sufficient. If it exceeds 5 g / m ² , the adhesive strength is sufficient. The texture of the composite sheet 20 decreases,
In addition, blocking occurs between the composite sheets 20.

The adhesive 23 may be applied entirely between the sheet 21 and the non-woven fabric 22 as shown in FIG. 1, but it may have a texture or the sheet 21 may be a moisture-permeable sheet. In this case, it is preferable to apply the coating intermittently from the viewpoint of maintaining the moisture permeability. Examples of the mode of the intermittent coating include a linear shape, a dot shape, a rectangular shape, a spiral shape, and the like. When the adhesive 23 is applied intermittently, the adhesive area ratio is set to 20 within the range of the above-mentioned coating amount.
It is preferable to apply so that the content is 〜60%. As a method for applying the adhesive 23, a so-called slot spray method, a curtain spray method, a melt blown method, a spiral spray method, a gravure method, and a method in which the adhesive 23 is applied in the form of a mist and in the form of a dot are used. 23 is applied in a linear manner.

The composite sheet 20 shown in FIG. 1 is prepared by subjecting the sheet 21 and the nonwoven fabric 22 to predetermined bonding means, for example, hot embossing or heat roll processing, especially hot embossing after being bonded by the adhesive. Is preferred. That is, the composite sheet 20 is different from the sheet 21
It is particularly preferable that the nonwoven fabric 22 is bonded to the nonwoven fabric 22 by the adhesive 23 and hot embossing.
By the hot embossing, the texture and flexibility can be improved, or the feel of the composite sheet 20 and the adhesive strength between the sheet 21 and the nonwoven fabric 22 can be further improved. The sheet 21 and the nonwoven fabric 2
It is also possible to effectively prevent the composite sheet 20 from shrinking and wrinkling due to a difference in tension (elongation rate) at the time of bonding with the composite sheet 2. The embossed area ratio of the composite sheet 20 by the hot embossing is preferably 40% or less of the entire area of the composite sheet 20.
More preferably, it is 0 to 30%. If the emboss area ratio exceeds 40%, the composite sheet 20 becomes hard and the texture such as softness decreases, or the composite sheet 20
May decrease in moisture permeability. The details of the hot embossing conditions and the like will be described later.

In the composite sheet 20 shown in FIG. 1, since the above-mentioned sheet 21 and the above-mentioned non-woven fabric 22 are joined by the above-mentioned adhesive, the bonding strength between the sheet 21 and the non-woven fabric 22 is high, and furthermore, the 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 g / m.
25 mm or more, more preferably 100 g / 25 m
m or more. There is no particular upper limit on 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 even more preferably 10 g / 50 mm or less. The lower limit of the blocking strength is not particularly limited, and the lower the better, 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 surface material 2, a liquid-impermeable back material 3,
An absorbent body (not shown) interposed therebetween is provided, and the front surface member 2, the rear surface member 3, and the first elastic member interposed therebetween are provided on the abdominal waist portion 5 and the back waist portion 5 '. Waist gathers 7 and 7 ′ including the member 6 are provided. The abdominal waist part 5 and the back waist part 5 ′ are arranged so as to be located around the front and rear ends of the absorber.

On the leg portions on both sides in the longitudinal direction of the diaper 1, leg gathers 9 and 9 'each comprising the front surface member 2, the back surface member 3, and the second elastic member 8 interposed therebetween are formed. Have been.

A fastening tape 10 for fastening the abdominal waist portion 5 and the back waist portion 5 'when the diaper 1 is mounted is provided on both sides in the width direction of the back waist portion 5' of the diaper 1. , 10 'are provided. On the surface of the back material 3 at the abdominal waist portion 5 of the diaper 1, a landing tape 11 is provided as a portion to which the fastening tape 10, 10 'is adhered.
The fastening tapes 10 and 10 ′ are configured to be fixed to the landing tape 11.

The absorber has a narrowed portion corresponding to the crotch portion of the diaper, and is formed in an hourglass shape. In the abdominal waist portion 5 and the back waist portion 5 ′ and the left and right legs located around the absorber, the first elastic member 6 and the second elastic member 8 are respectively connected to the surface material 2 and the back surface. 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, 7 'and leg gathers 9, 9' as shown in FIG. It is configured to fit the inseam.

The members constituting the diaper 1 will be described. The surface material 2 is preferably a liquid-permeable sheet that allows excrement to pass through the absorber, and has a feeling similar to 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 agent or paraffin wax to the periphery of the surface material 2 or a method of applying a hydrophilic compound such as an alkyl phosphate ester on the entire surface in advance and washing the periphery with warm water. For example, a material in which the peripheral portion of the surface material 2 is subjected to a water-repellent treatment to prevent leakage due to bleeding of urine or the like at the peripheral portion can also be preferably used.

As the absorber interposed between the front surface member 2 and the back surface member 3, a fibrous pulp as a main material and a polymer water-absorbing polymer in combination, a thermoplastic resin, a cellulose fiber, It is preferable to use a mixture of a high-molecular water-absorbing polymer and a heat-treated mixture. Also,
A mixture of a high-molecular-weight water-absorbing polymer and pulp may be used. In this case, the high-molecular-weight water-absorbing polymer may be present in any of the upper, middle and lower layers of the absorber. The high-molecular water-absorbing polymer is preferably in the form of particles having a holding performance capable of absorbing and holding a liquid 20 times or more its own weight and having a gelation performance. Examples of such a high molecular water-absorbing polymer include starch-acrylic acid (salt) graft copolymer, saponified starch-acrylonitrile copolymer, cross-linked sodium carboxymethyl cellulose, acrylic acid (salt) polymer And the like.

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' may be thread rubber, flat rubber, film-type rubber or film-like foam. Polyurethane or the like is preferably used.

Thus, 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 outward of the disposable diaper 1. As a result, the disposable diaper is
Due to the cloth-like texture of 2, the texture such as softness and the touch are improved. In addition, when a moisture-permeable sheet is used as the sheet 21 in the composite sheet 20, the vapor inside the diaper is released to the outside via the moisture-permeable sheet, so that the inside of the diaper has stuffiness and the wear of the wearer associated therewith. Skin irritation is prevented.

As described above, the composite sheet and the absorbent article according to the present invention have been described based on the preferred embodiments. However, the present invention is not limited to the above embodiments, but includes various modifications. . For example, in the composite sheet 20 of the embodiment shown in FIG. 1, the nonwoven fabric 2 is provided on the other surface of the sheet 21 bonded to the nonwoven fabric 22.
The same or different types of nonwoven fabrics or other sheets may be joined to form a three-layer composite sheet. In the composite sheet 20 of the embodiment shown in FIG.
The size of the sheet 21 and the size of the nonwoven fabric 22 may be the same or different. In addition, the above nonwoven fabric is 22
The sheet 21 may be continuously laminated or discontinuously laminated. In addition, the composite sheet can be used for applications requiring softness, texture and waterproofness, such as waterproof clothing, waterproof covers, and packaging materials, and particularly for applications requiring moisture permeability.

The embodiment shown in FIG. 2 is a deployable disposable diaper, but 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, and can be similarly applied to sanitary napkins, incontinence pads, and the like.

Next, a preferred method of 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 preferred method of manufacturing the disposable diaper of the embodiment shown in FIG.

In the disposable diaper 1 shown in FIG.
The composite sheet 20 as the backing material 3 is formed by applying the adhesive 23 having the above-mentioned physical properties on the above-mentioned sheet 21 having the above-mentioned physical properties at the above-mentioned coating amount, and then applying the above-mentioned physical properties on the coated surface. After the above-mentioned nonwoven fabric 22 having the above is bonded, it is preferably manufactured by hot embossing and joining. Note that the term “hot embossing” in the present specification refers to a case where the composite sheet is pre-heated and then embossed,
It means both the case where the composite sheet is embossed using the heated emboss.

The above-mentioned manufacturing method will be described in more detail with reference to FIG. 3. A melt blown coater 33 is provided on one surface of the sheet 21 unwound from the above-mentioned sheet winding 31.
The above-mentioned adhesive 23 is blown out in the form of a mist by using, and is applied in the above-described application amount in a dot-like application pattern. Next, the nonwoven fabric 22 unwound from the nonwoven fabric winding 32 is
The composite sheet is bonded to the coated surface to form a composite sheet, and the composite sheet is inserted between a pair of nip rolls 34, 34, thereby ensuring the adhesion between the sheet 21 and the nonwoven fabric 22. Subsequently, the composite sheet is hot-embossed by being inserted between a pair of embossing rolls 35, 35. The composite sheet 20 thus obtained is wound by a winder (not shown). In this case, instead of the embossing rolls 35, 35, a heat roll may be inserted between the heat rolls to increase the adhesive strength. The wound composite sheet is unwound and used in a usual process of manufacturing a disposable diaper, and the disposable diaper shown in FIG. 2 is manufactured.

As the embossing roll, a pair of rolls generally composed of an engraving roll and a smoothing 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 smoothing roll, a paper roll, a rubber roll, a silicone rubber roll, a urethane rubber roll, a metal roll, or the like can be used. In the apparatus shown in FIG. 3, one or both of these rolls are heated and used to perform hot embossing. The heating temperature of the embossing roll is preferably set to a temperature lower by at least 10 ° C. than the melting point of the sheet 21 or the nonwoven fabric 22 which is in direct contact with the embossing roll to be heated. If the embossing roll is heated to a higher temperature than this, the composite sheet may adhere to the embossing roll, or the composite sheet may be shrunk or wrinkled by heat. Also,
When both rolls are heated, a temperature difference (for example, 10 to 30 ° C.) may be applied between the engraving roll and the smoothing roll to perform hot embossing, or the texture and flexibility of the obtained composite sheet may be reduced. It is preferred in that respect. In this case, the heating temperature of the engraving roll is preferably higher than the heating temperature of the smoothing roll. Examples of the pattern of the engraving roll include, for example, pins, dot dots, turtle shells, lattices, vertical stripes, horizontal stripes, stitches, patterns, and the like, and are not particularly limited to those 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, and the like, but as a general range, 10 to 150 kg / c.
m is preferable.

Note that the description of the conventional method of manufacturing disposable diapers is appropriately applied to the points that have not been described in detail with respect to the method of manufacturing disposable diapers.

[0057]

The following examples illustrate the effectiveness of the composite sheet and the absorbent article of the present invention. 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 Industries, 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 properties shown in Table 1 were added, and the mixture was kneaded with a twin-screw kneader to form a pellet. Produced. The obtained pellets are supplied to an inflation molding machine, and the thickness is 40 μm.
Was formed. The obtained sheet was stretched at a stretching temperature of 50 ° C. using a roll stretching machine at a stretching ratio of 2.
The film was stretched three times to obtain a porous moisture-permeable sheet. The thickness of the moisture permeable sheet is 20 μm, and the moisture permeability is 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, an 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 ) (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
The adhesive strength at a width of 5 mm and the blocking strength at 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 the preparation of the diaper, no blocking of the composite sheet was observed, and no breakage of the composite sheet and no entanglement with the roll occurred. Further, the obtained disposable diaper was one in which the stuffiness was prevented and the texture and feel such as softness were improved.

<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> The composite sheet is wound about 1000 m around a paper tube to form a roll, and stored in an atmosphere at 50 ° C. for one 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.
The composite sheet is cut out to have a width of 50 mm along the MD direction and a length of 100 mm along the MD direction, which is used as a test piece. Using a Tensilon tensile tester, a 180 ° peel test (tensile speed: 500
m / min at a measurement temperature of 20 ° C.) to measure the blocking strength.

Examples 2 to 6 The same procedures as in Example 1 were carried out except that the adhesive was applied under the conditions shown in Table 3 and the hot embossing was performed at the emboss 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. In addition, the conditions of the hot embossing were a heating temperature of the embossing roll of 90 ° C. and a linear pressure of 60 kg / cm. Also,
The disposable diaper shown in FIG. 2 was produced using the obtained composite sheet. During the preparation of the diaper, no blocking of the composite sheet was observed, and no breakage of the composite sheet and no entanglement with the roll occurred. Further, the obtained disposable diaper was one in which the stuffiness was prevented and the texture and feel such as softness were improved.

Comparative Example 1 A composite sheet was obtained in the same manner as in Example 1 except that an SIS-based 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. In addition, 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 the 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 bonded by an adhesive having specific physical properties (Example 1) Nos. To 6) have a higher adhesive strength and a lower blocking strength (that is, less likely to cause blocking) than the composite sheet obtained by using a conventional hot melt (Comparative Example 1). I understand.
In particular, a composite sheet obtained by laminating the moisture permeable sheet and the nonwoven fabric and then performing hot embossing (Example 4)
In Nos. To 6), the adhesive strength was extremely high.

Examples 7 to 12 Low-density polyethylene [Ultzex 2080 manufactured by Mitsui Petrochemical Industries, Ltd.]
(Trade name)] 5 parts by weight of titanium oxide was added to 100 parts by weight, and the mixture was kneaded with a twin-screw kneader to produce pellets. The obtained pellet was supplied to a T-die molding machine to obtain a moisture-impermeable sheet having a thickness of 20 μm. Using the obtained moisture-impermeable sheet, the same adhesive as in Example 1 is applied under the conditions shown in Table 4 and hot embossing is performed at the emboss area ratio shown in Table 4 (Examples 10 to 12). A composite sheet was obtained in the same manner as in Example 1 except for ()). The same measurement as in Example 1 was performed on the obtained composite sheet. Table 4 shows the results. In addition, the conditions of the hot embossing are described in Examples 4 to
Same as 6. In addition, disposable diapers shown in FIG. 2 were produced using the obtained composite sheets. During the preparation of the diaper, no blocking of the composite sheet was observed, and no breakage of the composite sheet and no entanglement with the roll occurred.

[0068]

[Table 4]

As is clear from the results shown in Table 4, the composite sheet of the present invention in which a sheet having specific physical properties and a non-woven fabric having specific physical properties were bonded by an adhesive having specific physical properties (Example 7) 12) indicate that the adhesive strength is high and the blocking strength is low (that is, the blocking hardly occurs). In particular, in the composite sheet (Examples 10 to 12) obtained by laminating the non-permeable sheet and the nonwoven fabric and then performing hot embossing, the adhesive strength was extremely high.

[0070]

According to the present invention, there can be obtained a composite sheet having high adhesive strength and preventing occurrence of blocking. Therefore, when an absorbent article is manufactured using the composite sheet of the present invention, the composite sheet is effectively prevented from being torn or entangled with the roll during the manufacture. Further, according to the absorbent article of the present invention, stuffiness is prevented, and texture such as softness and feel 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 the drawings]

FIG. 1 is a schematic sectional view showing a 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 preferred method of manufacturing the disposable diaper of the embodiment shown in FIG.

[Explanation of symbols]

 Reference Signs List 20 composite sheet 21 sheet 22 nonwoven fabric 23 adhesive

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification code FI B32B 27/00 A41B 13/02 F A61F 13/18 320 C09J 201/00 (72) Inventor Kazuo Fujita Kabanecho, Akigaicho, Haga-gun, Tochigi Prefecture 2606 Inside Kao Corporation Research Laboratory (56) References JP-A-2-86676 (JP, A) JP-A 2-155639 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 C09J 1/00-201/10 A61F 13/15-13/84

Claims (9)

(57) [Claims] 1. A composite sheet in which a sheet and a nonwoven fabric are joined by 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 1.5 to 3.5 denier, its basis weight is 10 to 35 g / m ² , and the adhesive contains 20% by weight or more of amorphous polyalphaolefin (APAO) as a base polymer, and its melt viscosity is 180 ° C. 500 ~ 10,000c
is ps, the coating amount Ri 0.5 to 5 g / m ² der, composite sheet characterized that you have been wound into a roll state. 2. The sheet according to claim 1, wherein the sheet has moisture permeability, and the 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 at least one of a tackifier, a softener, and an antioxidant. 4. The adhesive has a melt viscosity of 180 ° C.
2. The composite sheet according to claim 1, wherein the molecular weight is 1,000 to 8,000 cps. 5. The composite sheet according to claim 1, wherein said composite sheet is hot-embossed. 6. The composite sheet according to claim 5, wherein an emboss area ratio by the hot embossing is 40% or less of an area of the entire composite sheet. 7. An adhesive strength between the sheet and the nonwoven fabric in the composite sheet is 30 g / 25 mm or more;
The blocking strength of the composite sheet is 20 g / 50 mm
The composite sheet according to claim 1, which is: 8. A method for producing a composite sheet in which a sheet and a nonwoven fabric are joined 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 0.5 to 3.0 denier, the basis weight is 10 to 35 g / m ² , and the adhesive contains at least 20% by weight of amorphous polyalphaolefin (APAO) as a base polymer, and has a melt viscosity of at least 20% by weight. 500 to 10,000c at 180 ° C
ps, and the coating amount is 0.5 to 5 g / m ² ,
Then, after applying the adhesive on the sheet and bonding the nonwoven fabric on the coated surface, the sheet and the nonwoven fabric are joined by a predetermined joining means , and then wound into a roll.
The method of producing a composite sheet according to claim Rukoto preparative. 9. The composite sheet according to claim 1, wherein the adhesive is intermittently applied to join the sheet and the nonwoven fabric.