JP2002316388A - Moisture permeable film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moisture permeable film which is excellent in waterproof properties and germproof properties, is heat-sealable with a polyolefin base material, and is inexpensive. SOLUTION: A laminate in which a film layer (I) containing a polyolefin resin and an inorganic substance, a film layer (II) containing an acid-modified polyolefin resin and an inorganic substance, and a film layer (III) formed from at least one selected from a thermoplastic polyurethane elastomer, a polyester elastomer, and a polyamide elastomer are laminated in turn and which is oriented uniaxially or biaxially is used as the moisture permeable film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moisture-permeable film, and more particularly, to a moisture-permeable film that can be used as a dehumidifier packaging material, a sanitary material such as a napkin for women, a diaper, and a medical material.

[0002]

2. Description of the Related Art As a moisture-permeable film, a microporous film obtained by uniaxially or biaxially stretching an unstretched film composed of a polyolefin-based resin and a highly filled inorganic filler, and a hydrophilic film are featured. Films made of polyurethane elastomers, polyester elastomers, polyamide elastomers, and the like are known.

The above microporous film is disclosed in
As disclosed in Japanese Patent Publication No. 438, the main component of the inorganic filler used is calcium carbonate, and the dispersion of the particle size distribution of the inorganic filler causes a variation in the microporous diameter. There have been problems such as leakage of liquid from the portion and passage of bacteria.

Accordingly, in the above-mentioned applications, a film made of a non-porous thermoplastic polyurethane elastomer, polyester elastomer, or polyamide elastomer has been used in some cases. For this reason, there has been proposed a method of using an adhesive or applying a urethane resin liquid to a nonwoven fabric as described in JP-A-63-179731. However, there is a problem that since the processing steps are complicated, the manufacturing cost is high, and it can be applied only to special products.

[0005]

SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide an inexpensive moisture-permeable film which is excellent in waterproofness and antibacterial properties, can be heat-sealed with a polyolefin substrate, and is inexpensive. Is to do.

[0006]

The invention according to claim 1 of the present invention (hereinafter referred to as the first invention) comprises a film layer (I) containing 30 to 60% by weight of a polyolefin resin and 70 to 40% by weight of an inorganic substance. ), A film layer (II) containing 40 to 60% by weight of an acid-modified polyolefin resin and 60 to 40% by weight of an inorganic substance, and at least one selected from thermoplastic polyurethane elastomers, polyester elastomers and polyamide elastomers. A laminate in which film layers (III) are laminated in this order, which is stretched in a uniaxial or biaxial direction.

The invention according to claim 2 of the present invention (hereinafter referred to as “second
The invention comprises a film layer (I) containing 30 to 60% by weight of a polyolefin-based resin and 70 to 40% by weight of an inorganic substance, and an acid-modified polyolefin-based resin 40 to 60%.
Film layer containing at least one selected from thermoplastic polyurethane elastomer, polyester elastomer and polyamide elastomer (III), acid-modified polyolefin resin 40 to 60% by weight and inorganic substance 6
A film layer (IV) containing 0 to 40% by weight, and
30-60% by weight of polyolefin resin and inorganic substance 70
A moisture-permeable film characterized in that a laminate in which film layers (V) each containing up to 40% by weight are laminated in this order is stretched in a uniaxial or biaxial direction.

Hereinafter, the present invention will be described in detail. As the moisture-permeable film of the first invention, a three-layer laminate in which a film layer (I), a film layer (II) and a film layer (III) are laminated in this order, which is uniaxially or biaxially stretched is used. Can be

As the film layer (I), a film composed of 30 to 60% by weight of a polyolefin resin and 70 to 40% by weight of an inorganic substance is used. Examples of the polyolefin-based resin include polyethylene and polypropylene, and examples of the inorganic substance include calcium carbonate and talc. In order to enhance the dispersibility of the calcium carbonate, a dispersant may be added, or the calcium carbonate may be subjected to a surface treatment.

If the content of the inorganic substance in the film layer (I) exceeds 70% by weight, the melt-formed film may become brittle and may not be stretched sufficiently, and the heat sealing strength with the polyolefin substrate may be insufficient. In addition, 3
If the amount is less than 0% by weight, sufficient air permeability cannot be provided, and it becomes difficult to obtain a required moisture permeability.

The film layer (I) may contain a pigment, an antioxidant, an antistatic agent, an ultraviolet absorber and the like.

The film layer (II) functions as an adhesive layer, and comprises a film layer (II) containing 40 to 60% by weight of an acid-modified polyolefin resin and 60 to 40% by weight of an inorganic substance. Is used. If the content of the inorganic substance in the film layer (II) exceeds 60% by weight, the melt-formed film may become brittle and may not be stretched sufficiently, and the heat sealing strength with the polyolefin substrate may be insufficient. On the other hand, when the amount of the inorganic substance is less than 40% by weight, sufficient air permeability cannot be provided, and it becomes difficult to obtain a required moisture permeability.

The acid-modified polyolefin resin is preferably one in which 0.1 to 1% by weight of the polyolefin resin is modified with maleic acid. If the ratio of maleic acid modification is less than 0.1% by weight, sufficient adhesion cannot be obtained, and if it exceeds 1% by weight, the film layer (I
The heat resistance of I) decreases. As the polyolefin-based resin, the same one as in the film layer (I) is used.

As the film layer (III), a film comprising at least one selected from thermoplastic polyurethane elastomers, polyester elastomers and polyamide elastomers is used.

Examples of the thermoplastic polyurethane elastomer include polytetramethylene glycol (PT)
MG), a polyol such as polypropylene glycol (PPG) or polyethylene glycol (PEG);
4'-diphenylmethane diisocyanate (MDI),
4,4'-dicyclohexylmethane diisocyanate (H
₁₂ MDI) and other isocyanates as chain extenders
Those reacted with 4-butanediol adipate are preferably used.

The above polyester elastomer includes:
A hard segment composed of polybutylene terephthalate (PBT) and a soft segment composed of PTMG or PEG are preferably used. As the polyamide elastomer, the hard segment is composed of 12-nylon, and the soft segment is PTMG or PE.
Those consisting of G are preferably used.

The film layer (I) and the film layer (II)
The method for producing the three-layer laminate in which the film layer (III) is laminated in this order is not particularly limited. After forming each layer by a T-die method, an inflation method, or the like, a feed block method, a multi-manifold And a method of laminating three layers by a multi-throttle die method or the like.

By stretching the three-layer laminate in a uniaxial or biaxial direction, the moisture-permeable film of the first invention is obtained. By stretching, the inorganic-containing film layers (I) and (II) become microporous layers and exhibit moisture permeability.

The moisture-permeable film of the second invention comprises a five-layer structure in which a film layer (I), a film layer (II), a film layer (III), a film layer (IV) and a film layer (V) are laminated in this order. A laminate obtained by stretching the laminate in a uniaxial or biaxial direction is used.

For the film layer (I), the film layer (II) and the film layer (III), the same compound as in the first invention is used. The film layer (IV) uses the same composition as the film layer (II), and the film layer (V) uses the same composition as the film layer (I).

The method for manufacturing the five-layer laminate according to the second invention is not particularly limited, and after forming each layer by a T-die method, an inflation method, or the like, a feed block method, a multi-manifold method, a multi-throttle die And a method of laminating five layers by a method.

By stretching the above five-layered laminate uniaxially or biaxially, the moisture-permeable film of the second invention is obtained. By stretching, the inorganic-containing film layers (I), (II), (IV) and (V) become microporous layers and exhibit moisture permeability.

When stretching the above three-layer or five-layer laminate,
The stretching ratio is preferably 1.1 to 2.5 times, more preferably 1.5 to 2 times. If the stretching ratio is less than 1.1 times, a microporous film cannot be obtained, so that sufficient moisture permeability cannot be exhibited. And it is difficult to obtain a good product.

The basis weight of the moisture-permeable film of the present invention is 20 to
200 g / m ² is preferred. If the basis weight is less than 20 g / m ² , uniform stretching becomes difficult, and if the basis weight is more than 200 g / m ² , the stiffness becomes too strong to use, resulting in poor practicality and economic efficiency.

The moisture permeability of the moisture-permeable film is governed by the thickness of the film layer (III) in which the nonporous film is used. The basis weight of the film layer (III) is 4 to 100 g /
m ² is preferred, and more preferably 10 to 50 g / m ² . If the basis weight is less than 4 g / m ² , molding becomes difficult, and if the basis weight exceeds 100 g / m ² , sufficient moisture permeability cannot be obtained.

The basis weight of the film layer (I) or (V) is 4
-100 g / m ² , more preferably 10-5
0 g / m ² . If the basis weight is less than 4 g / m ² , molding becomes difficult, and if the basis weight is more than 100 g / m ² , the stiffness becomes too strong, and the practicality and economic efficiency deteriorate.

The basis weight of the film layer (II) or (IV) is 4 to 100 g / m 2 for the same reason as the film layer (I).
² is preferred, and more preferably 10 to 50 g / m ² .

The moisture permeability of the moisture permeable film is 1,000
(G / m ² · 24 hours) or more, more preferably 3,000 (g / m ² · 24 hours) or more. When the moisture permeability is less than 1,000 (g / m ² · 24 hours),
Practicability deteriorates due to unevenness. The moisture permeability here is a value measured under the conditions of 40 ° C. and 90% relative humidity in accordance with JIS Z 0208.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail.
Examples will be described below, but the present invention is limited to these examples.
However, the present invention is not limited to this. (Example 1) Linear low density polyethylene as the first layer
(Density 0.920 g / cm^Three, MFR2.0g / 10
Min.) 45% by weight and fatty acid-treated calcium carbonate (flat
Composition comprising 55% by weight (average particle size: 2.5 μm), second layer
0.27% by weight of maleic acid-modified polypropylene
Pyrene (Mitsui Chemicals "Admer QF500") 50-fold
% And calcium carbonate treated with fatty acids (average particle size 2.
5 μm) a composition consisting of 50% by weight, and a third layer
And polyurethane elastomer (DIC Bayer
"Desmopan 8670" manufactured by Lupolymer, with polyol
PPG and PEG, MDI as isocyanate,
1,4-butanediol adipate used as chain extender
And co-extrusion using the T-die method.
A layer laminate was formed. Next, this three-layer laminate is
The film was stretched in the direction at a draw ratio of 1.8 times, and the basis weight was 35 g / m.^Two
Was obtained. After stretching, the first layer
Is the basis weight of 10g / m^Two, The basis weight of the second layer is 5 g / m ^Two,
The basis weight of the three layers is 20 g / m^TwoMet.

(Example 2) The first and fifth layers have the same composition as the first layer of the first embodiment, and the second and fourth layers have the same composition as the second layer of the first embodiment. As a layer, a polyamide elastomer ("PEBACS 10" manufactured by Atofina Japan)
74 ", a block copolymer of nylon-12 and PEG, melting point 160 ° C.), and coextruded by a T-die method to form a five-layer laminate. Next, this five-layer laminate was stretched in the longitudinal uniaxial direction at a stretch ratio of 2.0 times to obtain a moisture-permeable film having a basis weight of 50 g / m ² . After the stretching, the basis weight of the first and fifth layers was 10 g / m ² , the basis weight of the ^second and fourth layers was 5 g / m ² , and the basis weight of the third layer was 20 g / m ² .

Example 3 As the third layer, a polyester elastomer ("Perprene GP550" manufactured by Toyobo Co., Ltd.)
Melting point 180 ° C, polybutylene terephthalate and PTMG
And a block copolymer with PEG, melting point 180 ° C.), except that a five-layer laminate was formed in the same manner as in Example 2. Next, this five-layer laminate is placed in a longitudinal uniaxial direction.
The film was stretched at a stretch ratio of 0 to obtain a moisture-permeable film having a basis weight of 50 g / m ² . After stretching, the basis weight of the first and fifth layers was 10 g / m ² , the basis weight of the ^second and fourth layers was 5 g / m ² ,
The basis weight of the layer was 20 g / m ² .

(Comparative Example 1) Only the composition used as the first layer in Example 1 was formed into a film by a T-die method, and then stretched in a longitudinally uniaxial direction at a stretch ratio of 2.0 times to obtain a basis weight of 40 g / m2. ^Two
Was obtained.

(Comparative Example 2) The same polyester elastomer as in Example 3 was formed into a film by the T-die method, and the basis weight was 40 g.
/ M ² .

With respect to the films obtained in the above Examples and Comparative Examples, the performance of the following items was evaluated, and the results are shown in Table 1. (1) Moisture permeability According to JIS Z 0208, 40 ° C., relative humidity 9
The moisture permeability was measured under the condition of 0%.

(2) Heat Sealability After heat-sealing with a polypropylene spun bond having a basis weight of 18 g / m ² , the film was peeled off by hand to evaluate the heat sealability. The heat seal was performed at a seal bar temperature of 17
The test was performed under the conditions of 0 ° C., a sealing pressure of 0.2 MPa, and a sealing time of 2 seconds.

(3) Water pressure test A tissue and a film sample were placed on a smooth glass plate, and a cylindrical glass was pressed, and 500 ml of water colored with aqueous red ink was poured from above, and after 10 minutes, the red color was applied to the tissue. The presence or absence of ink adhesion was visually observed.

[0037]

[Table 1]

[0038]

The moisture-permeable film of the present invention has the above-mentioned structure, is excellent in waterproofness and antibacterial properties, can be heat-sealed with a polyolefin substrate, and has good moisture-permeable properties. It can be suitably used as an agent packaging material, a napkin for women, a sanitary material such as a diaper, a medical material, and the like.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08J 5/18 CES C08L 23/26 C08K 3/00 A61F 13/18 320 C08L 23/26 F term (Reference) 4C003 CA06 4F071 AA10 AA14 AA78 AB21 AB26 AE17 AF08 BA01 BB06 BC01 4F100 AA00A AA00B AA00D AA00E AA08A AA08B AH02A AH02B AK03A AK03B AK03D AK03E AK07B AK41C AK46C AK51C AK63A AL09C BA05 BA07 BA10A BA10E CA13A CA13B CA13D CA13E GB15 GB66 GB72 JA20A JA20B JA20D JA20E JD04 YY00A YY00B YY00D YY00E 4J002 BB031 BB121 BB211 CF101 CK041 DE236 DJ046 FD016

Claims (3)

[Claims] 1 to 30% by weight of a polyolefin resin
And a film layer (I) containing 70 to 40% by weight of an inorganic substance, and an acid-modified polyolefin-based resin 40 to 60
A film layer (II) containing at least one selected from the group consisting of thermoplastic polyurethane elastomers, polyester elastomers and polyamide elastomers in this order. The laminated body stretched in a uniaxial or biaxial direction. 2. 30 to 60% by weight of a polyolefin resin
And a film layer (I) containing 70 to 40% by weight of an inorganic substance, and an acid-modified polyolefin-based resin 40 to 60
Film layer containing at least one selected from thermoplastic polyurethane elastomer, polyester elastomer and polyamide elastomer (III), acid-modified polyolefin resin 40 to 60% by weight and inorganic substance 6
A film layer (IV) containing 0 to 40% by weight, and
30-60% by weight of polyolefin resin and inorganic substance 70
A moisture-permeable film, wherein a laminate in which film layers (V) each containing up to 40% by weight are laminated in this order is stretched in a uniaxial or biaxial direction. 3. The moisture-permeable film according to claim 1, wherein the acid-modified polyolefin resin is a maleic acid-modified polyolefin resin.