JPH09201909A - Moisture-permeable composite sheet and absorbent article using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the adhesive strength while high moisture permeability is kept by laminating a non-porous sheet consisting of a urethane and/or an ester elastomer and a polyolefin thermoplastic resin on a fiber assembly. SOLUTION: This moisture permeable composite sheet 1 is formed of a non-porous sheet 2 and a fiber assembly 3. The non-porous sheet 2 is formed by at first melting and kneading a mixture of a specified amt. of a urethane and/or an ester elastomer, a polyolefin thermoplastic resin and if necessary, another resin by means of an extruder and then, extruding the melted and kneaded article from a slit of a T-die and melt-molding it. The melt-molded non-porous sheet 2 is laminated on a fiber assembly 3 being prepd. separately from this or the non-porous sheet 2 is laminated just after the fiber assembly 3 is made into a sheet as a card web to obtain a moisture-permeable composite sheet 1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a moisture-permeable composite sheet and an absorbent article using the same, and more particularly to a moisture-permeable composite sheet having improved adhesive strength and an absorbent article using the same.

[0002]

2. Description of the Related Art A moisture permeable sheet is known in which a urethane or ester elastomer sheet is laminated on a non-woven fabric or the like. For example, JP-A-51-111290 discloses a film sheet made of a copolyester elastomer containing short chain ester units and long chain ester units as a polyester film sheet having excellent moisture permeability. The gazette states that
It is described that such a film sheet can be reinforced and used with a synthetic fiber woven fabric such as nylon or polyester.

Further, JP-A-6-134000 and JP-A-7-70936 produce a non-porous moisture permeable polyurethane film using a polyurethane resin synthesized mainly with polyethylene glycol and polyisocyanate, and at least Disclosed is a stretchable moisture-permeable waterproof sheet having a stretchable nonwoven fabric laminated on one surface thereof. And it is described that such a waterproof sheet is used as a back sheet of a diaper.

However, the urethane-based and ester-based elastomers used in the sheets described in the above publications do not have sufficient adhesive strength (laminate strength) when they are laminated on a non-woven fabric or the like, resulting in a laminated composite. Was difficult. Moreover, when trying to increase the adhesive strength, a decrease in the drape property (flexibility) of the sheet cannot be avoided.

Therefore, an object of the present invention is to provide a flexible moisture-permeable composite sheet having improved adhesive strength while maintaining high moisture permeability. Another object of the present invention is to provide an absorbent article which prevents stuffiness and has an excellent texture.

[0006]

Means for Solving the Problems As a result of intensive investigations by the present inventors, a non-porous sheet obtained by adding a polyolefin-based thermoplastic resin to a urethane-based and / or ester-based elastomer is applied to a non-woven fabric or the like. It has been found that a moisture-permeable composite sheet that can achieve the above object can be obtained by stacking the layers.

The present invention has been made on the basis of the above findings, and comprises a non-porous sheet made of a urethane-based and / or ester-based elastomer and a polyolefin-based thermoplastic resin laminated on a fiber assembly. The above object has been achieved by providing a characteristic moisture-permeable composite sheet.

The present invention also provides an absorbent article using the moisture-permeable composite sheet as a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retaining absorbent sheet interposed between these sheets. In an absorbent article comprising a body,
An absorbent article characterized by using, as the back sheet, a moisture-permeable composite sheet obtained by laminating a non-porous sheet made of a urethane-based and / or ester-based elastomer and a polyolefin-based thermoplastic resin on a fiber assembly. Is provided.

The present invention also provides a urethane-based and / or urethane-based compound as a preferred method for producing the moisture-permeable composite sheet.
Alternatively, the present invention provides a method for producing a moisture-permeable composite sheet, which comprises melt-forming a mixture of an ester-based elastomer and a polyolefin-based thermoplastic resin into a sheet, and then melt-laminating the mixture on a fiber assembly.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the moisture-permeable 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 moisture-permeable composite sheet of the present invention.

The moisture-permeable composite sheet 1 of the embodiment shown in FIG.
Is a non-porous sheet 2 made of a urethane-based and / or ester-based elastomer and a polyolefin-based thermoplastic resin, which is laminated on the fiber assembly 3. Hereinafter, the non-perforated sheet 2 and the fiber assembly 3 which constitute the moisture-permeable composite sheet 1 will be described respectively.

The non-porous sheet 2 is made of urethane-based and / or ester-based elastomer and polyolefin-based thermoplastic resin as described above. The urethane-based and ester-based elastomers can be used without particular limitation as long as they can exhibit moisture permeability when formed into a sheet. The urethane-based elastomer preferably used includes, for example, a block having a urethane bond as a hard segment, a polycarbonate-based polyol as a soft segment, an ether-based polyol, and a caprolactone-based polyester,
Alternatively, a thermoplastic elastomer including a block having an adipate polyester or the like can be used. Further, JP-A-7-70936, JP-A-6-134000, JP-B-6-67604, and JP-A-1-141.
It is also possible to use the urethane-based elastomers described in Japanese Patent No. 669 and Japanese Patent Publication No. 52-21042. On the other hand, those preferably used as the ester-based elastomer include, for example, a thermoplastic elastomer comprising a block having an aromatic polyester as a hard segment and an aliphatic polyether or a block having an aliphatic polyester as a soft segment. Is mentioned. Further, the ester-based elastomer described in JP-A-51-111290 can be used.

The urethane-based elastomer and the ester-based elastomer may be used alone,
Alternatively, both may be used in combination. When both are used in combination, there are no particular restrictions on the respective blending proportions, but when the urethane elastomer is used for the main blending or when a blocking prevention effect is imparted, the ester elastomer Select the hardness and blend.

As the olefinic thermoplastic resin which is the other component constituting the non-porous sheet 2, homopolymers such as ethylene and propylene and copolymers of ethylene and propylene with other polymerizable monomers are used. It can be used, but is not limited thereto. As the polymerizable monomer, for example, acrylic acid, acrylic acid ester, vinyl alcohol, maleic anhydride, methacrylic acid, methacrylic acid ester, glycidyl methacrylate, vinyl acetate and the like can be used. Preferred examples of the olefin-based thermoplastic resin include copolymers of ethylene with acrylic acid, ethyl acrylate, vinyl alcohol maleic anhydride or vinyl acetate.

The above olefinic thermoplastic resins may be used alone or in combination of two or more kinds. When two or more kinds of the above olefinic thermoplastic resins are used in combination, low density polyethylene (L
It is preferable to use DPE) and an olefin-based copolymer (for example, ethylene / ethyl acrylate copolymer) because the flowability and adhesiveness of the melt at the time of molding the non-porous sheet 2 are improved.

The non-porous sheet 2 is made of the elastomer 9
It is preferably composed of 9 to 51 parts by weight and 1 to 49 parts by weight of the above-mentioned polyolefin-based thermoplastic resin. If the content of the elastomer exceeds 99 parts by weight or the content of the polyolefin-based thermoplastic resin is less than 1 part by weight, the adhesive effect to the fiber assembly is low, and the content of the elastomer is 51 parts by weight. If the content is less than the above or the content of the above-mentioned polyolefin-based thermoplastic resin exceeds 49 parts by weight, the moisture permeability of the above-mentioned elastomer may be impaired, so the content is preferably in the above range. More preferably, the non-perforated sheet 2 is the elastomer 99.
-60 parts by weight, the above-mentioned polyolefin-based thermoplastic resin 1-
It consists of 40 parts by weight.

As described above, the non-porous sheet 2 is composed of the elastomer and the polyolefin thermoplastic resin, but may contain other resins in addition to these. Examples of such a resin include a resin that acts as a compatibilizing agent between the elastomer and the polyolefin-based thermoplastic resin. Such other resin can be preferably mixed in an amount of 0.1 to 10 parts by weight with respect to 100 parts by weight of the elastomer. In addition, various additives such as a lubricant, an antiblocking agent, a heat / light stabilizer, an antistatic agent, and a colorant may be added to the non-porous sheet 2 as necessary.

The non-perforated sheet 2 is liquid impermeable. At the same time, the non-perforated sheet 2 exhibits moisture permeability not in the form of fine pores but in the form of taking in, diffusing and releasing water vapor of the elastomer. The thickness of the non-perforated sheet 2 is not particularly limited, but is preferably 5 to 50 μm, and more preferably 5 to 30 μm from the viewpoint of drapeability (flexibility) as a composite sheet, texture and the like. preferable.

Next, the fiber assembly 3 in the moisture-permeable composite sheet 1 of the embodiment shown in FIG. 1 will be described. As the fiber assembly 3, a sheet-shaped fiber assembly, for example, a woven fabric or a nonwoven fabric of synthetic fibers can be used, and a nonwoven fabric is particularly preferably used. Preferred examples of the non-woven fabric include non-woven fabrics mainly composed of thermoplastic fibers,
For example, spunbonded non-woven fabric, card method non-woven fabric, melt blown non-woven fabric, spunlace non-woven fabric, needle punched non-woven fabric and the like are mentioned, but not limited to these.

In particular, it is preferable to use a polyolefin-based nonwoven fabric as the fiber assembly 3, and in particular, a core-sheath type in which a highly elastic resin is used as a core and a polyolefin resin having a low elasticity and / or a low melting point is used as a sheath. When the non-woven fabric formed by using the composite fiber of (1) is used, the texture of the resulting moisture-permeable composite sheet is further enhanced and the elasticity is high, and the adhesiveness between the non-woven fabric and the non-porous sheet 2 is also good. It is particularly preferable because it exists. The thickness of the fibers in the non-woven fabric is preferably as thin as possible from the viewpoint of flexibility and texture, and particularly preferably 3 denier or less. Although the lower limit of the thickness is not particularly limited, it is up to about 0.1 denier in actual production.

The thickness of the fiber assembly 3 is not particularly limited, but is 0.1 to 5 mm from the viewpoint of cost and texture.
(Under a load of 0.5 g / cm ² ) is preferable,
More preferably, it is 0.3 to 3 mm. Similarly, the basis weight of the fiber assembly 3 is not particularly limited, but is preferably 10 to 100 g / m ² , and more preferably 10 to 50 g / m ² from the viewpoint of cost and the like. .

The moisture-permeable composite sheet 1 of the embodiment shown in FIG.
Has moisture permeability as a whole, and its moisture permeability is preferably 0.5 g / [100 cm ² · hr] or more. The moisture permeability is 0.5 g / [100 cm ² · h
If it is less than r], the moisture-permeable composite sheet of the present invention may cause stuffiness when used as a back sheet of a disposable diaper or the like. The moisture-permeable composite sheet 1 is preferably impermeable to liquid in addition to having moisture permeability, and its water pressure resistance is preferably 50 cm or more,
More preferably, it is 100 cm or more. The water pressure resistance is 5
If it is less than 0 cm, it may not be possible to prevent leakage of urine and the like when the moisture-permeable composite sheet of the present invention is used as a back sheet of a disposable diaper or the like.

The moisture-permeable composite sheet 1 of the embodiment shown in FIG.
There is no particular limitation on the grammage, but if the grammage is increased too much, the cost becomes high, so that the grammage is 15 to 130 g / m 2.
It is preferably ² and more preferably 25 to 50 g / m ² .

The moisture-permeable composite sheet of the present invention is not limited to the embodiment shown in FIG. 1 and various modifications are possible. For example, when the moisture-permeable composite sheet of the present invention is used as a back sheet of a disposable diaper, a landing tape for attaching an adhesive fastening tape is provided at a predetermined position of the fiber assembly, or mechanically. You may provide the recessed material which can be engaged with the convex member of a fastener. Further, in the moisture-permeable composite sheet of the embodiment shown in FIG. 1, one or more layers of another fiber assembly or sheet may be laminated on the non-porous sheet 2. Similarly, the above fiber assembly 3
Another non-perforated sheet or another sheet may be laminated on the upper layer. In the moisture-permeable composite sheet of the embodiment shown in FIG. 1, the size of the non-perforated sheet 2 and the size of the fiber assembly 3 do not have to be the same, and for example, a predetermined size on the non-perforated sheet 2 may be used. The fiber assembly may be laminated only at the position.

Next, a preferred method for manufacturing the moisture-permeable composite sheet 1 of the embodiment shown in FIG. 1 will be described. The above-mentioned moisture-permeable composite sheet 1 is preferably produced by melt-laminating a mixture of urethane-based and / or ester-based elastomer and polyolefin-based thermoplastic resin on a fiber assembly during melt-forming into a sheet. .

The above method will be described in detail. First, a mixture obtained by mixing a predetermined amount of the urethane-based and / or ester-based elastomer and the polyolefin-based thermoplastic resin with other resin as necessary is extruded. Melt and knead. Next, the melt-kneaded product is extruded from the slit of the T-die, melt-formed into a sheet, and directly melt-laminated on a fiber assembly separately manufactured.
In this case, the distance (that is, the air gap) between the fiber assembly and the slit of the T die can be melt-laminated with the fiber assembly in a molten state before the sheet-shaped melt-molded product is solidified. Such a distance. In addition, the forming speed (melt laminating speed) at this time is set to a speed at which film breakage or thickness unevenness of the non-porous sheet does not occur.

After the melt lamination, the laminate is inserted between a pair of heating rolls for thermocompression bonding, or by point bonding using a heating embossing roll or the like, the adhesion between the non-perforated sheet and the fiber assembly. May be further improved to obtain the moisture-permeable composite sheet.

In the above method, the melt-formed non-perforated sheet may be laminated on a prefabricated fiber assembly, or the non-perforated sheet may be formed into a sheet by using the fiber assembly as a card web. Immediately after lamination, it may be laminated. In addition, the lamination surface of the fiber assembly may be subjected to corona treatment or frame treatment prior to lamination to further improve the adhesiveness between the fiber assembly and the non-porous sheet.

The preferred method for producing the moisture-permeable composite sheet of the embodiment shown in FIG. 1 has been described above in detail. However, the method for producing the moisture-permeable composite sheet is not limited to the above method. For lamination with the fiber assembly, thermocompression-bonding lamination, frame lamination, or the like, or lamination using a hot melt adhesive, a liquid adhesive, or the like may be performed.

Next, an absorbent article using the moisture-permeable composite sheet of the embodiment shown in FIG. 1 will be described with reference to FIG. 2, taking a disposable diaper as an example. Here, FIG. 2 is a perspective view showing a disposable diaper as an example of an absorbent article using the laminated composite sheet of the embodiment shown in FIG.

The disposable diaper 10 shown in FIG. 2 comprises a liquid-permeable top sheet 11, a liquid-impermeable back sheet 12, and a liquid-retaining absorber (not shown) interposed between these sheets. Thus, the abdominal waistline portion 13 located on the abdominal side of the wearer and the back side waistline portion 14 located on the backside are formed when the wearer is in use. A pair of engaging portions 15, 15 made of a convex member of a mechanical fastener are provided on both sides of the back waistline portion 14. Such a configuration and the material for forming the topsheet 11 and the absorber are the same as the conventionally known configuration and material. Thus, FIG.
In the disposable diaper 10 shown in (1), the moisture-permeable composite sheet is used as the back sheet 12. As described above, since the moisture-permeable composite sheet has moisture permeability, the disposable diaper 10 using the moisture-permeable composite sheet as the back sheet effectively prevents stuffiness of the body fluid absorbed therein. be able to.

In the disposable diaper 10, the moisture permeable composite sheet used as the back sheet 12 is used so that the fiber assembly side thereof faces the outside of the disposable diaper 10. By using the moisture-permeable composite sheet in this manner, a cloth-like feel can be imparted to the disposable diaper 10 and a disposable diaper excellent in texture such as touch and appearance can be obtained.

Furthermore, in the disposable diaper 10, the fiber assembly in the moisture-permeable composite sheet is
It also serves as a recess member that can be engaged with the engaging portions 15 and 15. Therefore, the engaging portion 1 is provided on the back sheet 12.
It is not necessary to separately provide a recessed material that can be engaged with 5, 15,
The manufacturing process is simplified. In addition, the disposable diaper 1 described above
When 0 is rolled up and discarded, the engaging portions 15 and 15 can be engaged with any position of the back sheet 12 and discarded, which is extremely convenient.

Examples of the absorbent article of the present invention include the above-mentioned expandable disposable diapers, pants-type disposable diapers, sanitary napkins, incontinence pads, and the like. The moisture-permeable composite sheet is an absorbent article. It is used in a desired shape depending on the application.

[0035]

EXAMPLES The moisture-permeable composite sheet of the present invention will be described in more detail below with reference to examples. However, it goes without saying that the present invention is not limited to such an embodiment. In addition,
In the following description, “part” means part by weight unless otherwise specified.

Example 1 70 parts of an ester type elastomer (XG-830 manufactured by Nippon Synthetic Chemical Industry) and an olefin type thermoplastic resin (ethylene / ethyl acrylate copolymer, manufactured by Mitsui DuPont Polychemical Co., Ltd.) A702)
30 parts by weight are mixed with a Henschel mixer, the obtained resin mixture is melt-kneaded with a twin-screw extruder, and then extruded into a sheet form from a T-die (basis weight 16.9 g / m ² ) to prepare in advance. On a suction heat-bonded non-woven fabric made of polyethylene (weight 20 g / m ² ), molding speed 1
Melt lamination was performed at 00 m / min to produce a moisture permeable composite sheet. The air gap at this time is 120 mm.
Met. Further, the moisture permeability and the laminate strength of this moisture permeable composite sheet were measured by the following methods. Table 1 shows the results.

<Measurement of Moisture Permeability> The moisture permeability was measured according to JIS Z0208. <Measurement of Lamination Strength> After cutting the obtained moisture-permeable composite sheet into a test piece having a width of 25 mm and a length of 100 mm,
A T-peel test was performed with a tensile tester at a chuck distance of 40 mm, and an average of 5 peak values was obtained. The tensile speed was 300 mm / min, and measurement was performed in the MD direction (the sheet forming direction was the longitudinal direction of the test piece) and the TD direction (the direction perpendicular to the sheet forming direction was the longitudinal direction of the test piece).

Examples 2 to 4 The resin mixture shown in Table 1 was used in place of the resin mixture used in Example 1, and the molding processing conditions shown in Table 1 were used instead of the molding processing conditions in Example 1. A moisture-permeable 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 moisture-permeable composite sheet. Table 1 shows the results.

Comparative Example 1 A moisture permeable composite sheet was obtained by the same procedure as in Example 1 except that the thermoplastic polyolefin resin was not used and only 100 parts by weight of the ester elastomer was used. The same measurement as in Example 1 was performed on the obtained moisture-permeable composite sheet. Table 1 shows the results.

[0040]

[Table 1]

As is clear from the results shown in Table 1, the moisture-permeable composite sheets of the present invention (Examples 1 to 4) obtained by laminating a non-porous sheet containing a thermoplastic polyolefin resin and a non-woven fabric are laminated. The moisture-permeable composite sheet of Comparative Example 1 using a non-porous sheet containing no polyolefin-based thermoplastic resin had the same flexibility and higher adhesive strength.

[0042]

As described above, according to the present invention,
By laminating a non-porous sheet obtained by adding a polyolefin thermoplastic resin to a urethane-based and / or ester-based elastomer with a fiber assembly, a flexible moisture permeability with improved adhesive strength while maintaining high moisture permeability A composite sheet is obtained. In addition, the absorbent article using the moisture-permeable composite sheet as the back sheet has stuffiness prevented and excellent texture.

[Brief description of drawings]

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

FIG. 2 is a perspective view showing a disposable diaper as an example of an absorbent article using the laminated composite sheet of the embodiment shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Moisture permeable composite sheet 2 Non-porous sheet 3 Fiber assembly 10 Disposable diaper 11 Liquid permeable top sheet 12 Liquid impermeable back sheet

Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08L 75/04 NGG A41B 13/02 F (72) Inventor Ryohiko Gunji 2606 Kao Stocks Association Kakai-cho, Haga-gun, Tochigi Prefecture Company research institute

Claims (5)

[Claims] 1. A moisture-permeable composite sheet, comprising a non-porous sheet made of a urethane-based and / or ester-based elastomer and a polyolefin-based thermoplastic resin laminated on a fiber assembly. 2. The non-perforated sheet is the elastomer 9
The moisture-permeable composite sheet according to claim 1, which comprises 9 to 51 parts by weight and 1 to 49 parts by weight of the polyolefin-based thermoplastic resin. 3. A moisture vapor transmission rate of 0.5 g / [100 cm ² · h
r] or more and the water pressure resistance is 50 cm or more, The moisture-permeable composite sheet according to claim 1 or 2. 4. An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retaining absorber interposed between these sheets, wherein the back sheet is urethane. An absorbent article characterized by using a moisture-permeable composite sheet obtained by laminating a non-porous sheet composed of a system-based and / or ester-based elastomer and a polyolefin-based thermoplastic resin on a fiber assembly. 5. A moisture-permeable composite sheet, which comprises melt-forming a mixture of a urethane-based and / or ester-based elastomer and a polyolefin-based thermoplastic resin into a sheet, and then melt-laminating the mixture on a fiber assembly. Production method.