JP2003191381A - Moisture-permeable film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moisture-permeable film with flexibility and excellent moisture permeability and with a small dimensional change during immersion in water and excellent resistance to water permeability. <P>SOLUTION: The moisture-permeable film is made into a laminated body constitution of a layer (I) comprising a moisture-permeable resin and a layer (II) comprising a thermoplastic resin which has a different composition from the moisture-permeable resin and exhibits a dimensional change of at most 10% when it is immersed in water for 24 hr and is a resin except polyolefin resins. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible moisture-permeable film having excellent dimensional stability and water permeation resistance, and is particularly suitable for desiccant, sanitary, medical and clothing. Regarding

[0002]

2. Description of the Related Art Conventionally, attention has been paid to materials having excellent moisture permeability in the sanitary field or the clothing field. As such a material, there is known one in which an inorganic filler is mixed with polypropylene or polyethylene to form a film, which is then stretched to form micropores.
However, it has been difficult to achieve a high level of both moisture permeability and water resistance in such materials.

In order to improve the water permeation resistance of the above microporous film, Japanese Unexamined Patent Publication (Kokai) No. 4-90337 discloses a microporous membrane layer made of polyolefin and a water-impermeable polyester elastomer layer having a specific moisture permeability. Has been proposed. However, since this laminated body still contains a layer made of polyolefin, there is a problem in that it is inferior in flexibility and has a rough feeling, and thus the wearing feeling is not good.

As a moisture-permeable material excellent in water resistance, JP-A-59-111847 proposes a "flexible laminated substance" made of a non-porous material. With such a laminated material, a material having excellent moisture permeability can be obtained by specifying the composition and amount of the soft segment. Also,
As a material having excellent moisture permeability, Japanese Patent Laid-Open No. 62-290714
The publication discloses a "method for producing a non-porous moisture-permeable polyurethane film".

However, the above-mentioned materials still have insufficient moisture permeability for use in the intended use of the present invention, and further improvement is desired. Generally, in order to improve the moisture permeability, it is necessary to increase the hydrophilicity, but by increasing the hydrophilicity, the dimensional change rate when immersed in water is also increased at the same time, so the dimensional stability deteriorates, It cannot be put to practical use.

[0006]

SUMMARY OF THE INVENTION In view of the above problems, the present invention has an object of having flexibility and excellent moisture permeability, a small dimensional change rate when immersed in water, and water resistance. To provide an excellent moisture permeable film.

[0007]

The moisture-permeable film of the present invention has a layer (I) made of a moisture-permeable resin and a composition different from that of the moisture-permeable resin, and has a dimensional change rate of 10% when immersed in water for 24 hours. A moisture-permeable film, which is a laminate with the following layer (II) made of a thermoplastic resin other than a polyolefin resin, and has a moisture permeability of 3000 (g / m ² ···) measured according to JIS Z 0208. 24 hours) or more, the dimensional change rate when immersed in water for 24 hours is 10% or less, and the water resistance measured according to JIS L 1092 is 200 kPa or more.

The present invention will be described in detail below. The moisture-permeable film of the present invention includes a layer (I) made of a moisture-permeable resin.
And a layer (II) made of a thermoplastic resin other than the polyolefin resin is used. In the above-mentioned laminated body, it is preferable that the layer (II) is the outermost layer in order to improve dimensional stability and reduce stickiness of the film surface when wet. Therefore, when the above-mentioned laminated body is a three-layered laminated body, a constitution of layer (II) / layer (I) / layer (II) is preferable.

If an adhesive is used between the layer (I) and the layer (II) in the above laminate, the moisture permeability of the moisture permeable film may be adversely affected, which is not preferable. In the present invention, by using a thermoplastic resin having a functional group as the layer (II), the layer (I) and the layer (II) can be laminated without using an adhesive.

JIS Z 0208 of the moisture permeable film
The water vapor permeability measured according to the standard of 3000 (g / m ² ·
24 hours) or more, preferably 5000 (g /
m ² · 24 hours) or more. Water vapor transmission rate is 3000 (g
/ M ² · 24 hours), the water vapor permeability is insufficient, and when used for clothing, for example, it causes discomfort due to unevenness or stickiness.

The dimensional change rate of the moisture permeable film when immersed in water for 24 hours is limited to 10% or less, preferably 5% or less. If the dimensional change rate is larger than 10%, the dimensional change rate of the portion in contact with water becomes large, which may cause wrinkles. The occurrence of such wrinkles not only impairs the appearance, but also weakens the resistance to tearing.

[0012] JIS L 1092 of the moisture permeable film
The water resistance measured according to the above is limited to 200 kPa or more, and preferably 300 kPa or more. If the water resistance is less than 200 kPa, the water resistance becomes insufficient and water leakage such as rain is likely to occur when used as waterproof clothing.

The layer (II) according to the present invention is formed of a thermoplastic resin other than the polyolefin resin. When a polyolefin resin such as polyethylene or polypropylene that has been conventionally used in a microporous film is used as the thermoplastic resin, the flexibility of the resulting moisture-permeable film is reduced,
It causes a stiff feeling and makes it uncomfortable to wear. In addition, when a highly flexible material is selected among polyolefin resins such as LLDPE (linear low-density polyethylene) polymerized with a metallocene catalyst and EVA (ethylene-vinyl acetate copolymer), the strength of the film itself decreases. However, it cannot be put to practical use. Further, when immersed in water, peeling may occur at the interface between the layer (I) and the layer (II) due to the difference in the polarities of the materials.

The thermoplastic resin used in the layer (II) has an ester bond (-COO-), an amide bond (-NHCO-) and a urethane bond (-NHCO) in the molecule.
Those containing at least one functional group selected from O-) are preferable. By using the thermoplastic resin containing the above functional group, sufficient adhesion is obtained with the layer (I), and both layers undergo interfacial peeling when immersed in water as in the case of using a polyolefin resin. Such problems disappear.

The thermoplastic resin used in the layer (II) is, for example, an ester type elastomer having an ester bond (-COO-) or an amide bond (-NH).
Examples of those having CO-) include amide elastomers, and those having urethane bonds (-NHCOO-) include urethane elastomers. In the layer (II), these elastomers may be used alone or in combination of two or more kinds.

Further, it is preferable to use a layer made of a porous resin as the layer (II). The layer made of such a porous resin can be obtained by stretching a thermoplastic resin containing a water-repellent filler made of an organic compound having an average particle size of 1 to 10 mμ.

By using the water-repellent filler in the layer (II), the interfacial peeling property between the thermoplastic resin and the filler is improved, and the hole forming property by stretching is improved. When an inorganic compound such as calcium carbonate, which is generally used, is used as a filler for forming the above-described micropores, pores are not formed by stretching because of high affinity with the thermoplastic resin. Although a surface of an inorganic compound is treated with a higher fatty acid such as stearic acid, silicone oil, or a silane compound, a water-repellent filler can be obtained.
It is not possible to form enough holes.

As the organic compound constituting the water-repellent filler, for example, one made of a water-repellent polymer material such as polytetrafluoroethylene or ultra-high molecular polyethylene is used, and as a commercially available product, for example, manufactured by Clariant Co., Ltd. Examples thereof include “Ceridust” and “Miperon” manufactured by Mitsui Chemicals, Inc.

When the average particle diameter of the water-repellent filler is less than 1 mμ, the dispersibility in the layer (II) is lowered, the uniformity of the resulting moisture-permeable film is lowered, and the film is easily broken during stretching. Moldability is also reduced and sufficient moisture permeability cannot be obtained. Also, the average particle size is 10 m
If it is larger than μ, the film tends to be broken during stretching and the formability is deteriorated. It is preferably 5 to 10 mμ.

Two of the thermoplastic resins constituting the above layer (II)
The storage elastic modulus at 3 ° C. is preferably 1 to 100 MPa, more preferably 10 to 100 MPa. If the storage elastic modulus is less than 1 MPa, the strength of the moisture-permeable film obtained will be insufficient, and if it exceeds 100 MPa, the flexibility of the moisture-permeable film obtained will decrease, and the feeling of wearing when used for clothing may deteriorate. There is.

The layer (I) according to the present invention is made of a moisture-permeable resin.
It is formed. As the moisture-permeable resin, a polyether compound is used.
Thermoplastic Elastomer Containing Minute (A) as a Constituent Component
Is preferably used, and the polyether component (A)
Is a C / O (carbon / oxygen) atomic ratio of 2 to 2.5.
Lioxyalkylene (-C_nH _2nO-)
Those are preferable. The C / O atomic ratio is greater than 2.5
The affinity of the resulting thermoplastic elastomer with water
And the moisture permeability is reduced.

As the above-mentioned polyether component (A), polyethylene glycol in which the C / O atomic ratio of polyoxyalkylene is 2 is preferable. The polyether component (A) is a mixture of polyethylene glycol and polyoxyalkylene having a C / O atomic ratio of 3 or more,
You may use what was adjusted so that C / O atomic ratio might be 2.5 or less.

Examples of the polyether component (A) in which the C / O atomic ratio of the polyoxyalkylene is 3 or more include polypropylene glycol, polyhexamethylene glycol, poly (ethylene glycol-tetramethylene glycol) copolymer, Examples thereof include poly (ethylene glycol-propylene glycol) copolymers.

The number average molecular weight of the polyether component (A) is preferably 500 to 3000, more preferably 1000 to 2000. Number average molecular weight is 500
When it is smaller, the flexibility and moisture permeability of the resulting thermoplastic elastomer may be reduced. When the number average molecular weight is more than 3,000, the compatibility with the polyester component (B) described later is lowered, the degree of polymerization of the thermoplastic elastomer obtained does not increase, and sufficient mechanical strength may not be imparted. The number average molecular weight of the polyether component (A) is a numerical value corresponding to the average molecular weight of the polyether (a) usually used as a raw material.

The content of the polyether component (A) in the thermoplastic elastomer is preferably 50 to 95% by weight, more preferably 60 to 90% by weight. When the content of the polyether component (A) is less than 50% by weight, the flexibility of the thermoplastic elastomer decreases and
Since the component with high molecular mobility decreases, the moisture permeability also decreases. Further, if the content of the polyether component (A) is more than 90% by weight, it becomes impossible to impart sufficient mechanical strength to the thermoplastic elastomer.

The glass transition temperature of the thermoplastic elastomer is preferably -20 ° C or lower, more preferably -30 ° C.
It is the following. When the glass transition temperature is higher than −20 ° C., sufficient rubber elasticity cannot be obtained at low temperature, molecular mobility is lowered, and moisture permeability is also lowered.

The above-mentioned glass transition temperature means a temperature at which, among the maximum values of the loss tangent (tan δ) obtained by viscoelasticity measurement, the maximum values due to the micro Brownian motion of the thermoplastic elastomer appear. This glass transition temperature is measured by a viscoelastic spectrometer.

The thermoplastic elastomer preferably contains the polyether component (A) and the polyester component (B) described below as constituent components. As the polyester component (B), 50 to 100% by weight of a short-chain polyester component represented by the following general formula (1) and 50 to 0% by weight of a long-chain polyester component represented by the following general formula (2).
Those consisting of are preferred. ^{-CO-R 1 -CO-O-} R 2 -O- ····· (1) -CO-R 3 -CO-O-R 4 - ····· (2) wherein, R ¹ and R ³ represents a divalent aromatic hydrocarbon group having 6 to 12 carbon atoms, R ² represents an alkylene group having 2 to 8 carbon atoms, and R ⁴ represents —R—O— (wherein R represents 2 carbon atoms. ??? 8 represents an alkylene group).

When the content of the short-chain polyester component in the polyester component (B) is less than 50% by weight, the melting point of the polyester component (B) becomes low, which adversely affects the mechanical strength of the resulting thermoplastic elastomer at high temperatures. There is.

The short-chain polyester component is obtained, for example, by reacting an aromatic dicarboxylic acid or its ester with a low molecular weight diol. The long-chain polyester component is obtained, for example, by reacting an aromatic dicarboxylic acid or its ester with a high molecular weight diol.

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid, paraphenylenedicarboxylic acid,
Dimethyl terephthalate, dimethyl isophthalate, dimethyl orthophthalate, dimethyl naphthalene dicarboxylate,
Examples include dimethyl paraphenylene dicarboxylate and the like, and these may be used alone or in combination of two or more kinds.

Examples of the low molecular weight diol include aliphatic chain diols and aliphatic cyclic diols, and examples of the aliphatic chain diols include ethylene glycol and
1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene Examples thereof include glycol, and these may be used alone or in combination of two or more kinds.
Examples of the aliphatic cyclic diol include, for example, 1,
4-cyclohexane dimethanol, 1,2-cyclohexane diol, 1,4-cyclohexane diol, etc. are mentioned, and these may be used individually and may use 2 or more types together.

Examples of the above-mentioned high molecular weight diols include:
Polyethylene glycol, polypropylene glycol,
Examples thereof include polytetramethylene glycol, polyhexamethylene glycol, poly (ethylene oxide / tetramethylene oxide) copolymer, and poly (ethylene oxide / propylene oxide) copolymer.

The number average molecular weight of the polyester component (B) is preferably 500 to 5,000, more preferably 5
It is 00 to 2000. When the number average molecular weight is less than 500, the blocking property of the polyester component (B) may be lowered, the melting point may be lowered, and the mechanical strength of the obtained thermoplastic elastomer at high temperature may be lowered. Further, when the number average molecular weight exceeds 5,000, the compatibility with the polyether component (A) becomes low, and thus the thermoplastic elastomer obtained does not have a high degree of polymerization and may not be able to have sufficient mechanical strength. . The number average molecular weight of the polyester component (B) is a numerical value corresponding to the average molecular weight of the polyester (b) usually used as a raw material.

The thermoplastic elastomer containing the above polyether component (A) as a constituent can be obtained by a known method. For example, an aromatic dicarboxylic acid or its ester can be added in an excess amount of a low molecular weight diol and, if necessary, a high molecular weight. The transesterification reaction is carried out by heating at 160 to 200 ° C. in the presence of a catalyst such as tetrabutyl titanate together with a diol, and subsequently, at a reduced pressure of 240 to 250
A thermoplastic elastomer can be obtained by carrying out a polycondensation reaction at ° C.

Further, the above-mentioned thermoplastic elastomer is obtained by binding the polyether component (A) with the polyisocyanate component (C), or the polyether component (A).
It is preferred that the polyester component (B) and the polyester component (B) are bound by the polyisocyanate component (C).

The polyisocyanate component (C) is preferably a diisocyanate component represented by the following general formula (3). —O—CO—NH—R ⁵ —NH—CO—O— (3) In the formula, R ⁵ is an alkylene group having 2 to 15 carbon atoms, a phenylene group, or a phenylene group and a methylene group. Represents a group bonded with.

As the thermoplastic elastomer containing the urethane-bonding component represented by the above general formula (3), those obtained by polyaddition reaction of a compound having a hydroxyl group at the molecular end and an isocyanate compound can be used,
Examples thereof include thermoplastic polyurethane elastomers and polyether ester elastomers chain-extended with an isocyanate compound; polyesters (b) and polyethers (a) reacted with polyisocyanates (c).

The structure of the polyisocyanate component (C) is not particularly limited as long as it has two or more isocyanate groups in the same molecule, but the average number of isocyanate groups per molecule is 2 to 2.2. Those in the range are preferred. Examples of the polyisocyanate compound (c) having an average number of isocyanate groups per molecule of 2 include, for example, aromatic diisocyanates such as 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate and naphthalene diisocyanate; 1,2-ethylene. Diisocyanate, 1,
3-propylene diisocyanate, 1,4-butane diisocyanate, 1,6-hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3
Examples thereof include cyclohexane diisocyanate, isophorone diisocyanate, and aliphatic diisocyanates such as hydrogenated 4,4′-phenylmethane diisocyanate.

The polyisocyanate compound (c) having an average number of isocyanate groups per molecule of more than 2.2
Alternatively, the polyisocyanate compound (c) having an average number of isocyanate groups of 2 may be mixed to adjust the average number of isocyanate groups per molecule to a range of 2 to 2.2 for use.

A typical example of the polyisocyanate compound (c) having an average number of isocyanate groups per molecule of more than 2.2 is polymeric MDI. Examples of commercially available products include "Millionate MR" manufactured by Nippon Polyurethane Co., Ltd.
200 "(average isocyanate group number 2.8), triphenylmethane triisocyanate (average isocyanate group number 3.0), tris (isocyanatophenyl) thiophosphate (average isocyanate group number 3.0), hexamethylene triisocyanate (average isocyanate group number 3) .0)) and the like.

The molar amount of the isocyanate group contained in the above polyisocyanate compound (c) is the group containing active hydrogen contained in the polyether (a) and polyester (b) used in the present invention (which can react with the isocyanate group. The molar amount of (group) is preferably 0.8 to 1.05 times, and more preferably 0.9 to 1.01 times. The above-mentioned polyether (a), polyester (b) and polyisocyanate compound (c) are mentioned above in the explanation of the polyether component (A), polyester component (B) and polyisocyanate component (C), respectively. Compounds similar to those used are used.

The molar ratio of the above isocyanate groups is 0.
When it is smaller than 8, the molecular weight of the obtained thermoplastic elastomer becomes low, and sufficient mechanical strength may not be obtained. Further, the molar ratio of the number of isocyanate groups,
When it is more than 1.05, the amount of side reaction products containing an unstable allophanate group or buret group in the resulting thermoplastic elastomer increases, resulting in deterioration of moldability and deterioration of physical properties of the resulting elastomer over time. May be noticeable.

The thermoplastic elastomer formed by combining the polyether component (A) and the polyester component (B) with the polyisocyanate component (C) comprises the polyether (a) and the polyisocyanate compound (c). To give a prepolymer having both ends isocyanated, and a second step of reacting the prepolymer with a polyester (b) having hydroxyl groups at both ends. It is preferable to manufacture it after this.

In the first step, the molar amount of the isocyanate group contained in the polyisocyanate compound (c) is 1. The molar amount of the group containing active hydrogen capable of reacting with the isocyanate group contained in the polyether (a) is 1. It is preferably 1 to 2.2 times, and more preferably 1.2 to 2 times.

When the molar amount ratio is less than 1.1, both ends of the prepolymer to be produced are completely isocyanated, which may hinder the reaction in the second step. On the other hand, when the molar ratio exceeds 2.2, the unreacted polyisocyanate compound (c) remains, so that it causes a side reaction during the reaction in the second step and contains an allophanate group or a buret group. The amount of side reaction products increases, which may result in deterioration of moldability and physical properties of the resulting thermoplastic elastomer.

The reaction temperature in the first step is 100 to 24.
0 degreeC is preferable, More preferably, it is 160-220 degreeC. If the reaction temperature is less than 100 ° C, the reaction may not proceed sufficiently, and if it exceeds 240 ° C, the polyether (a) may be decomposed, resulting in marked coloring of the thermoplastic elastomer.

In the second step, the prepolymer produced in the first step is reacted with the polyester (b). Here, the molar amount of the isocyanate group contained in the polyisocyanate compound (c) is the same as that of the group containing active hydrogen contained in the polyether (a) and the group containing active hydrogen contained in the polyester (b). It is preferably 0.8 to 1.05 times, and more preferably 0.9 to 1.01 times the total molar amount with the molar amount. By selecting such a molar amount range, it becomes difficult for a side reaction to occur, the resulting thermoplastic elastomer has a large molecular weight, and the physical properties are excellent.

The reaction temperature in the second step is 100 to 24.
0 degreeC is preferable, More preferably, it is 160-220 degreeC. If the reaction temperature is less than 100 ° C, the reaction may not proceed sufficiently, and if it exceeds 240 ° C, the prepolymer may be decomposed, and a thermoplastic elastomer having sufficient strength may not be obtained. Here, the polyester (b) may be separately melted by heating and added to the prepolymer by using a pump, or the prepolymer may be added after the polyester (b) is heated and melted by an extruder. .

It is preferable to use a bulk reaction as the reaction at the time of producing the above-mentioned thermoplastic elastomer because the reactivity in the second step is improved. The reaction equipment is not particularly limited, but it is preferable to use a single-screw or twin-screw extruder.
In particular, considering the good efficiency of stirring and mixing, among the extruders, a co-rotating twin screw extruder or a different rotating twin screw extruder is more preferable, and a co-rotating meshing twin screw extruder is more preferable. is there. By using such a reaction equipment, the reactivity is improved particularly in the second step. Moreover, since the reaction of the first step and the second step is continuously performed,
It is preferable to use a tandem type extruder.

A catalyst can be used when stirring and mixing the above-mentioned polyether (a), polyester (b) and polyisocyanate compound (c). Examples of the catalyst include diacyl stannous tin, tetraacyl stannic tin,
Dibutyltin oxide, dibutyltin dilaurate, dimethyltin malate, tin dioctanoate, tin tetraacetate, triethyleneamine, diethyleneamine, triethylamine, naphthenic acid metal salt, octylic acid metal salt, triisobutylaluminum, tetrabutyl titanate,
Examples thereof include calcium acetate, germanium dioxide, antimony trioxide and the like, and these may be used alone or in combination of two or more kinds.

As described above, the prepolymer obtained by reacting the polyether (a) with the polyisocyanate compound (c) and having both ends isocyanated is reacted with the polyester (b) having hydroxyl groups at both ends. By so doing, the polyether component (A) and the polyester component (b) are not chain-extended by the polyisocyanate compound (c) alone, and the polyether component (A) and the polyester component (B) are surely separated from each other by the polyisocyanate component (C). A thermoplastic elastomer consisting of a block copolymer bound by (1) is obtained. Further, the prepolymer and the polyester (b) are partially reacted to serve as a compatibilizing agent for the polyether (a) and the polyester (b), and the compatibility between the polyether (a) and the polyester (b). Polymerization is possible even when the ratio is poor.

Further, as compared with the case of polycondensation, the thermal history given to the polyether (a) at the time of polymerization is reduced, so that the decomposition and deterioration of the polyether (a) can be suppressed. Furthermore, by using the polyisocyanate compound (c), it is possible to reduce the acid generated in the polymerization system.

Further, by controlling the equivalence of the polyether (a), the polyester (b) and the polyisocyanate compound (c), for example, in the second step, excess polyester (b) relative to the prepolymer (b) can be obtained. It is possible to use the polyester component (B) at the molecular end of the obtained thermoplastic elastomer by reacting As a result, the melting point can be increased, and the moldability and high temperature physical properties of the thermoplastic elastomer are improved.

Layer (I) constituting the moisture-permeable film of the present invention
A stabilizer may be used for (II) during or after its production. Examples of the stabilizer include pentaerythritol tetrakis [3- (3,5-di-t-butyl-4].
-Hydroxyphenyl) propionate, octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N'-hexane-1,6-diylbis [3- (3,5-di- Hindered phenolic antioxidants such as t-butyl-4-hydroxyphenylpropionemide, diethyl {[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl} phosphonate; Tris ( 2,4-di-t-butylphenyl) phosphite, bis [2,4-bis (1,1-
Dimethylethyl) -6-methylphenyl] ethyl ester phosphorous acid, tetrakis (2,4-di-t-butylphenyl) [1,1-biphenyl] -4,4'-diylbisphosphonite, bis (2 , 4-Di-t-butylphenyl) pentaerythritol diphosphite, 4,4'-
Butylidene-bis (3-methyl-6-t-butylphenyl-di-tridecyl) phosphite, bis (2,6-
A phosphorus-based stabilizer such as di-t-butyl-4-methylphenyl) pentaerythritol-di-phosphite; 3-hydroxy-5,7-di-t-butyl-furan-2-one and o-xylene Examples include lactone-based heat stabilizers such as reaction products (for example, "HP-136" manufactured by Ciba Specialty Chemicals).

The ester-based elastomer of the present invention contains fibers, inorganic fillers, flame retardants, and
You may add additives, such as a ultraviolet absorber, an antistatic agent, an inorganic substance, and a higher fatty acid salt.

Examples of the fibers include glass fibers,
Inorganic fibers such as carbon fibers, boron fibers, silicon carbide fibers, alumina fibers, amorphous fibers, and silicon / titanium / carbon fibers; organic fibers such as aramid fibers. Examples of the inorganic filler include calcium carbonate, titanium oxide, mica, talc and the like. Examples of the flame retardant include hexabromocyclododecane, tris- (2,3-dichloropropyl) phosphate, pentabromophenyl allyl ether, and the like.

Examples of the ultraviolet absorber include p-
t-butylphenyl salicylate, 2-hydroxy-4
-Methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5-trihydroxybutyrophenone and the like can be mentioned.

Examples of the antistatic agent include N, N
Examples thereof include bis (hydroxyethyl) alkylamine, alkylallyl sulfonate, and alkyl sulfanate. Examples of the inorganic material include barium sulfate,
Examples thereof include alumina and silicon oxide. Examples of the higher fatty acid salt include sodium stearate, barium stearate, sodium palmitate and the like.

The layers (I) and (II) constituting the moisture permeable film may be mixed with other thermoplastic resins and rubber components to modify their properties. Examples of the thermoplastic resin include polyolefin, modified polyolefin, polystyrene, polyvinyl chloride, polyamide, polycarbonate, polysulfone, polyester and the like.

Examples of the rubber component include natural rubber, styrene-butadiene copolymer, polybutadiene,
Polyisoprene, acrylonitrile-butadiene copolymer, ethylene-propylene copolymer (EPM, EPD
M), polychloroprene, butyl rubber, acrylic rubber,
Examples thereof include silicone rubber, urethane rubber, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, ester-based thermoplastic elastomer, and amide-based thermoplastic elastomer.

In the moisture-permeable film of the present invention, for example, the layer (I) and the layer (II) are formed into a film by a water-cooled or air-cooled coextrusion inflation method or a coextrusion T-die method, and then uniaxially or biaxially. Method for stretching: Method for laminating layer (I) consisting of microporous thermoplastic resin film with thermoplastic elastomer as layer (I) by extrusion lamination method: Method for dry laminating microporous thermoplastic resin film and thermoplastic elastomer film The layer (I)
And a laminate of layer (II). Among these, the method of forming a film by a water-cooled or air-cooled coextrusion inflation method or a coextrusion T-die method and then stretching the film in a uniaxial or biaxial direction allows the thickness of each layer to be controlled relatively freely. preferable.

In the moisture permeable film, the proportion of layer (I) in the total thickness of the laminate is preferably 30 to 70%. When the proportion of the layer (I) is less than 30%, the flexibility and water resistance of the resulting moisture-permeable film may be reduced, and when the proportion of the layer (I) is greater than 70%, the moisture-permeable film obtained. The dimensional stability when immersed in water may deteriorate, and the moisture permeability may decrease.

The moisture-permeable film of the present invention may be used alone or may be laminated with a cloth or the like. The type of cloth and the method of laminating are not particularly limited. The moisture-permeable film of the present invention includes sundry items such as dehumidifiers and fragrances; sanitary items such as diapers and sanitary items; medical items such as adhesive back sheets and drapes; moisture-permeable waterproof clothing, hospital bed covers, etc. It is preferably used in applications where moisture permeability is required.

(Function) The moisture-permeable film of the present invention comprises a laminate of a layer (I) made of a moisture-permeable resin and a layer (II) made of a thermoplastic resin having a small dimensional change rate when immersed in water. By being configured, dimensional stability becomes high when immersed in water. Since the layer (II) is composed of a specific thermoplastic resin and a filler, the layer (I) has excellent adhesion to the layer (I) and has excellent pore-forming properties by stretching, and thus has high moisture permeability and excellent flexibility. Express.

Further, since the thermoplastic elastomer constituting the layer (I) has the soft segment composed of the specific polyether component (A), the affinity with water is enhanced and the adsorption of water molecules is promoted. . Further, the layer (I) has a specific glass transition temperature and a certain amount of soft segment, whereby the molecular mobility of the thermoplastic elastomer is enhanced,
Promotes the diffusion of water molecules. Due to these molecular designs, since the layer (I) has a very high moisture permeability which has not been heretofore obtained, the resulting moisture permeable film is imparted with a very high moisture permeability.
Furthermore, since the layer (I) has no pores, the moisture-permeable film has high water resistance.

[0067]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in more detail below with reference to Examples, but the present invention is not limited to these Examples.

Synthesis of thermoplastic elastomer 100 parts by weight of dimethyl terephthalate, 102 parts by weight of 1,4-butanediol, 0.3 part by weight of tetrabutyl titanate as a catalyst, and 1,3,5-trimethyl-2 as a stabilizer. 0.3 parts by weight of 4,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene and 0.3 parts by weight of tris (2,4-di-t-butylphenyl) phosphite. In addition, the reaction system under nitrogen at 200 ℃
The temperature was maintained for 3 hours to carry out a transesterification reaction. The progress of the transesterification reaction was confirmed by measuring the amount of distilled methanol. After the transesterification reaction proceeded, the temperature was raised to 240 ° C. in 20 minutes, and depressurization operation was performed. The polymerization system reached a degree of reduced pressure of 266 Pa or less in 20 minutes. As a result of polycondensation reaction for 10 minutes in this state, 112 parts by weight of white polyester was obtained. This polyester has a number average molecular weight of 1,000 and an acid value and a hydroxyl value of 0 (μ
eq / g) and 2000 (μeq / g). This is referred to as polyester (b).

As the polyether (a), the number average molecular weight is 1000, the hydroxyl value is 2000 (μeq / g), and the acid value is 0.
(Μeq / g) of polyethylene glycol 300 parts by weight, and polyisocyanate compound (c) having an NCO value of 8
87.5 parts by weight of 000 (μeq / g) of 4,4′-diphenylmethane diisocyanate was supplied from the first barrel of a twin-screw extruder (L / D = 58 manufactured by Toshiba Machine Co., Ltd.), and 5 barrels to the Polyester (b) 100
200 parts after feeding parts by weight using a forced feeder
Was melt-kneaded to obtain pellets of a thermoplastic elastomer having a glass transition temperature of −30 ° C. and containing 62% by weight of a polyether component (A) having a C / O atomic ratio of 2.0.

The number average molecular weight, acid value and hydroxyl value of the polyester (b) were measured by the following methods. (A) Number average molecular weight gel permeation chromatography (“HLC 8 manufactured by Tosoh Corporation”
020 series ”). Two “HFIP 806M” manufactured by Shodex are used as columns, and hexafluoroisopropanol (0.005) is used as a solvent.
N sodium trifluoroacetate was added), and polymethyl methacrylate was used as a standard.

(B) Acid value A sample was dissolved in a benzyl alcohol / chloroform mixed solvent, and then neutralization titration was carried out using a phenol red indicator to determine the acid value. (C) A hydroxyl value sample and succinic anhydride are dissolved in a nitrobenzene / pyridine mixed solvent and reacted for 10 hours, the reaction solution is reprecipitated with methanol, and the acid value of the obtained reaction product is measured. The hydroxyl value was used.

(D) Using a glass transition temperature viscoelasticity spectrometer (“RSA-11” manufactured by Rheometric Scientific Effie), a temperature rising rate of 3 ° C./minute, a frequency of 1.61 Hz, and a strain of 0.05%.
It was measured at.

The acid value and the hydroxyl value of the polyether (a) and the isocyanate value (NCO value) of the polyisocyanate compound (c) are those guaranteed by the manufacturer.

(Example 1) The layer (I) was filled with the above thermoplastic elastomer, the layer (II) was filled with 50% by weight of an ester elastomer ("Hytrel 4067" manufactured by Toray Industries, Inc.) and polytetrafluoroethylene having an average particle size of 3 µm. Material (Clariant "Seridust 9202F") 50% by weight
The mixture of and is supplied to an extruder, respectively, and by the co-extrusion T-die method using a feed block die, Hytrel /
After forming a laminate having a three-layer structure of thermoplastic elastomer / Hytrel, the obtained laminate is vertically and uniaxially 3
Stretched twice to give a total thickness of 30 μm and a layer ratio of 3: 6: 3
A moisture permeable film having a layered structure was obtained. In addition, Hytrel 4
The storage elastic modulus and the dimensional change rate of 067 were measured on a film having a thickness of 100 μm obtained by press molding.

(Example 2) A moisture permeable film was obtained in the same manner as in Example 1 except that the layer ratio was changed to a three-layer structure of 3: 4: 3.

Example 3 Example 1 was repeated except that the filler used in the layer (II) was replaced with a polytetrafluoroethylene filler having an average particle size of 7 μm (“Cellidust 9205F” manufactured by Clariant). A moisture permeable film was obtained in the same manner.

Example 4 Example 4 was repeated except that an amide elastomer (“Pebax MV1041” manufactured by Atofina) was used as the layer (II) instead of the ester elastomer (“Hytrel 4067” manufactured by Toray). A moisture permeable film was obtained in the same manner as in 1.

(Comparative Example 1) Except that the filler used in the layer (II) was replaced with ultrahigh molecular weight polyethylene having an average particle size of 25 μm (“Miberon XM221U” manufactured by Mitsui Chemicals, Inc.)
When a film was formed and stretched in the same manner as in Example 1, the film was cut during stretching and a moisture permeable film could not be obtained. (Comparative Example 2) As the layer (II), linear low-density polyethylene (“Ultra Zex 1520L” manufactured by Mitsui Chemicals, Inc.) 5
0% by weight and fatty acid surface-treated calcium carbonate having an average particle size of 3 μm (“PO-150-B-1” manufactured by Shiraishi Calcium Co., Ltd.
0 ") A film was formed and stretched in the same manner as in Example 1 except that a mixture of 50% by weight was used.
At the time of stretching, peeling occurred between layers (I) and (II), and a moisture permeable film could not be obtained.

With respect to the moisture-permeable films obtained in the above Examples and Comparative Examples, the performance evaluation of the following items was conducted, and the results are shown in Tables 1 and 2. (1) Moisture permeability Measured according to JIS Z 0208. (2) Dimensional change rate Write a 100 mm square on the surface of the moisture-permeable film,
After soaking in water at 23 ° C for 24 hours, remove from the water,
The length of the diagonal line of the square immediately after taking out was measured, and the dimensional change rate was calculated from the following formula. Dimensional change rate (%) = [(L-141.4) / 141.
4] × 100 Here, L represents the average value of the lengths of the diagonal lines.

(3) Water resistance The water resistance test of JIS L 1092 (method B) was carried out, and the pressure at which water leaked was measured according to the high pressure method. The evaluation was carried out by using a plate and sandwiching a polyester non-woven fabric having a basis weight of 40 g between the film and the plate.

(4) Storage elastic modulus Using a viscoelasticity spectrometer (“RSA-11” manufactured by Rheometric Scientific Effie), temperature rising rate 3 ° C./min, frequency 1.61 Hz, strain 0.05%
It was measured at.

[0082]

[Table 1]

[0083]

[Table 2]

[0084]

EFFECT OF THE INVENTION The moisture-permeable film of the present invention has the above-mentioned constitution, has good flexibility, extremely high moisture permeability and water permeability, and has a small dimensional change rate when immersed in water.
Therefore, it can be suitably used as a moisture permeable film for desiccant, sanitary, medical and clothing.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F100 AH00B AH00H AK01A AK01B                       AK41B AK46B AK54A AL09A                       BA02 BA25 CA23B DE01B                       DE01H EJ37 GB15 GB66                       GB72 JA20 JA20B JB16A                       JB16B JD04 JD04A JD05                       JK07B JK13 JK17 YY00                       YY00B

Claims (6)

[Claims] 1. A layer (I) comprising a moisture-permeable resin, and the moisture-permeable layer.
Of different composition from water-soluble resin and size when immersed in water for 24 hours
Other than polyolefin resin with a rate of change in method of 10% or less
Of the thermoplastic resin and layer (II)
Wet film, conforming to JIS Z 0208
The measured water vapor transmission rate is 3000 (g / m ²・ 24 hours or more
Above, dimensional change rate of 10% when immersed in water for 24 hours
Below, and measured according to JIS L 1092
The water resistance is 200 kPa or more.
A moisture permeable film. 2. A moisture-permeable resin constituting the layer (I) is a thermoplastic elastomer containing a polyether component (A) as a constituent, and a polyoxyalkylene (constituting the polyether component (A) ( -C _n H _2n O-) of C /
O atomic ratio is 2 to 2.5, and the content of the polyether component (A) in the thermoplastic elastomer is 45 to 95% by weight.
And the glass transition temperature of the thermoplastic elastomer is −20 ° C. or less, The moisture permeable film according to claim 1. 3. The thermoplastic resin constituting the layer (II) comprises an ester bond (—COO—) and an amide bond (—NHCO).
-) And urethane bond (-NHCOO-) at least 1 sort (s) or more functional group is contained, The moisture permeable film of Claim 1 or 2 characterized by the above-mentioned. 4. The layer (II) comprises a porous resin layer obtained by stretching a thermoplastic resin containing a water-repellent filler made of an organic compound and having an average particle size of 1 to 10 μm. Item 4. The moisture-permeable film according to any one of items 1 to 3. 5. A thermoplastic resin constituting the layer (II).
Storage elastic modulus in ° C is 1-100 MPa, The moisture permeable film according to any one of claims 1 to 4 characterized by things. 6. The moisture permeable film according to claim 1, wherein the proportion of the layer (I) is 30 to 70% of the total thickness of the laminate.