JP2002307614A - Multilayered flexible film or sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multilayered flexible film or sheet having flexibility and excellent moisture permeability, reduced in dimensional change ratio at the time of immersion in water and excellent in water impermeability. SOLUTION: The multilayered flexible film or sheet is constituted by laminating a layer comprising a thermoplastic resin other than an elastomer on at least one surface of an elastomer layer, and the moisture permeability and dimensional change ratio thereof are respectively set to specific ranges.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a multilayer flexible film or sheet suitably used in the fields of medical care, hygiene, medicine, food, clothing and the like.

[Prior art]

[0002] In the field of sanitary and clothing, a material having excellent moisture permeability has been attracting attention. As such a material, a material in which an inorganic filler is mixed with polypropylene or polyethylene, formed into a film, and then stretched to form microporous material is known. However, it is difficult to make such a material compatible with moisture permeability and water resistance at a high level, and there is a drawback that it is inferior in flexibility.

[0003] Non-porous materials are examples of moisture-permeable materials having excellent resistance to water penetration. As such a material, for example, a "flexible laminated material" is proposed in JP-A-59-111847. By specifying the composition and amount of the soft segment, a material excellent in moisture permeability can be obtained from this laminated material. As a material having excellent moisture permeability, Japanese Patent Application Laid-Open No. 62-290714 proposes "a method for producing a nonporous moisture-permeable polyurethane film".

[0004] However, these materials have insufficient moisture permeability, and further improvement is desired. Generally, it is necessary to increase the hydrophilicity in order to improve the moisture permeability. However, when the hydrophilicity is increased, there is a problem that the expansion coefficient when immersed in water is also increased.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a multilayer flexible film or sheet having flexibility, excellent moisture permeability, small dimensional change upon flooding, and excellent water resistance. is there.

[0006]

Means for Solving the Problems The multilayer flexible film or sheet of the present invention is a multilayer flexible film or sheet comprising a thermoplastic resin layer other than the elastomer laminated on at least one surface of an elastomer layer.
08 is 3,000 (g / m
Is ^2, 24 hours) or more, and dimensional change rate when immersed in water for 24 hours is equal to or less than 10%.

In the multilayer flexible film or sheet of the present invention (hereinafter simply referred to as multilayer flexible film), a thermoplastic resin layer other than the elastomer (hereinafter simply referred to as thermoplastic resin layer) is laminated on at least one surface of the elastomer layer. The laminated body used is used.

[0008] JIS Z 02 of the above multilayer flexible film
08 is 3,000 (g / m2).
It is limited to ² · 24 hours) or more, preferably 5,000
(G / m ² · 24 hours) or more. The moisture permeability is 3,000
If it is less than 0 (g / m ² · 24 hours), sufficient air permeability cannot be obtained. For example, when used for clothing, water vapor will condense. May cause pleasure.

Further, the dimensional change when the multilayer flexible film is immersed in water for 24 hours is limited to 10% or less,
Preferably it is 5% or less. When the dimensional change rate exceeds 10%, the dimensional change rate of the portion that comes into contact with water increases, which causes wrinkles. The occurrence of such wrinkles not only impairs the appearance but also reduces the resistance to tearing.

The measurement of the dimensional change rate is calculated by the following method. First, 100 μm is applied to the surface of the multilayer flexible film of the present invention.
Draw a square of square mm, and put this multilayer flexible film in 2
After being immersed in water at 3 ° C. for 24 hours, it is taken out of the water, and the length of the diagonal line of the square immediately after being taken out is measured. The dimensional change rate is calculated by substituting the average value L of the lengths of the diagonal lines into the following equation. Dimensional change rate (%) = [(L-141.4) / 141.
4)] × 100

The thermoplastic resin constituting the thermoplastic resin layer is not particularly limited as long as it satisfies the physical properties described above. However, in order not to impair the flexibility, ester-based elastomers, amide-based elastomers, and urethane-based elastomers can be used. It is preferable to use a thermoplastic resin elastomer such as a system elastomer.

Further, the thermoplastic resin layer includes, for example,
Medical polyurethane, polyester, polyolefin,
A resin such as polystyrene may be used.

The thermoplastic resin is characterized by a small dimensional change when immersed in water for 24 hours. However, since it has a low affinity for water, it can be used as a non-porous film as a thermoplastic resin layer. Since a multilayer flexible film having high moisture permeability cannot be obtained, the thermoplastic resin layer is preferably formed as a microporous layer (microporous film).

The thermoplastic resin layer may be formed of a thermoplastic resin containing an inorganic substance, and the content of the inorganic substance is preferably 20 to 70% by weight, more preferably 30 to 5% by weight.
0% by weight. When the content of the inorganic substance is less than 20% by weight, the moisture permeability of the thermoplastic resin layer becomes too low.
The resulting multilayer flexible film may have a low moisture permeability. On the other hand, when the content of the inorganic substance exceeds 70% by weight, the thermoplastic resin layer becomes brittle and may not be stretched sufficiently, or may have poor appearance.

Examples of the inorganic substances include calcium oxide, calcium carbonate, calcium hydroxide, magnesium oxide, magnesium carbonate, magnesium hydroxide, barium oxide, barium carbonate, aluminum oxide, aluminum hydroxide, titanium oxide, and zirconium oxide. No. The surface of these inorganic substances may be treated with a fatty acid in order to improve the dispersibility in the thermoplastic resin.

The above-mentioned elastomer contains a polyether component (A) as a structural unit, and a polyoxyalkylene group (—C _n ) constituting the polyether component (A).
_H2nO- ) having a carbon / oxygen atomic ratio of 2.0 to 2.5 is preferred. When the carbon / oxygen atom ratio is smaller than 2.0, the crystallinity of the polyether component (A) increases,
The flexibility of the obtained elastomer is reduced. When the carbon / oxygen atomic ratio is larger than 2.5, the affinity between the obtained elastomer and water is reduced, and the moisture permeability is also reduced. As a result, steam sterilization may be deteriorated.

As such a polyether component (A), polyethylene glycol having a carbon / oxygen atom ratio of 2.0 is more preferable, and polyethylene glycol having a carbon / oxygen atom ratio of 3.0 or more is preferred. The components may be mixed to adjust the carbon / oxygen atomic ratio in the range of 2.0 to 2.5.

Examples of the polyether component having a carbon / oxygen atomic ratio of 3.0 or more include, for example, polypropylene glycol, polyhexamethylene glycol, poly (ethylene glycol-tetramethylene glycol) copolymer, and poly (ethylene glycol-propylene). Glycol) copolymer.

The number average molecular weight of the polyether component (A) is preferably from 500 to 3,000, more preferably from 1,000 to 2,000. Number average molecular weight is 500
If it is less than 10, the flexibility of the obtained elastomer may decrease, and the moisture permeability may further decrease. On the other hand, when the number average molecular weight exceeds 3,000, the compatibility with the polyester component (B) described below is reduced, the degree of polymerization of the obtained elastomer is not increased, and sufficient mechanical strength may not be obtained. The number average molecular weight of the polyether component (A) is a numerical value corresponding to the average molecular weight of the polyether (a) described later.

The proportion of the polyether component (A) in the elastomer is preferably from 50 to 95% by weight, more preferably from 60 to 90% by weight. When the proportion of the polyether component (A) is less than 50% by weight, flexibility may be reduced, and components having high molecular mobility may be reduced, so that moisture permeability may also be reduced. If the proportion of the polyether component (A) is more than 95% by weight, sufficient mechanical strength may not be obtained.

The glass transition temperature of the above elastomer is -2.
0 ° C. or lower, more preferably −30 ° C.
It is below ° C. If the glass transition temperature is higher than −20 ° C., it is difficult to obtain sufficient rubber elasticity at a low temperature, and the molecular mobility and the moisture permeability may be reduced. The glass transition temperature is determined by the loss tangent (t) obtained by the viscoelasticity measurement.
An δ) means the temperature at which the maximum due to the micro-Brownian motion of the elastomer appears. This glass transition temperature is a value measured by a viscoelastic spectrometer.

The elastomer may contain the polyester component (B) as a constituent unit.
As the polyester component (B), those composed of a short-chain polyester component represented by the following general formula (1) and / or a long-chain polyester component represented by the following general formula (2) are preferable. —CO—R ¹ —CO—O—R ² —O— (1) —CO—R ¹ —CO—O—R ³ — (2) In the formula, R ¹ is the number of carbon atoms A divalent aromatic hydrocarbon group having 6 to 12 and R ² each represent an alkylene group having 2 to 8 carbon atoms. R ³ is composed of a repeating unit represented by — (R ⁴ —O) _n —, R ⁴ is an alkylene group having 2 to 8 carbon atoms, and n is a positive integer.

The polyester component (B) preferably comprises 50 to 100% by weight of the short-chain polyester component (1) and 50 to 0% by weight of the long-chain polyester component (2). When the content of the short-chain polyester component (1) is less than 50% by weight, the melting point of the polyester component (B) decreases,
High temperature mechanical strength of the resulting elastomer may be adversely affected.

The short-chain polyester component (1) is obtained by reacting an aromatic dicarboxylic acid or an ester thereof with a low molecular weight diol. The long-chain polyester component (2) is obtained by reacting an aromatic dicarboxylic acid or an ester thereof with a high molecular weight diol.

Examples of the aromatic dicarboxylic acids or esters thereof include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalene dicarboxylic acid, paraphenylenedicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate, dimethyl orthophthalate, and dimethyl naphthalene dicarboxylate. And dimethyl paraphenylenedicarboxylate. These may be used alone or in combination of two or more.

Examples of the low molecular weight diol include:
Examples thereof include aliphatic chain diols and aliphatic cyclic diols. Examples of the aliphatic chain diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5- Examples thereof include pentanediol, 1,6-hexanediol, diethylene glycol, and triethylene glycol, and these may be used alone or in combination of two or more. As the aliphatic cyclic diol, for example,
Examples thereof include 1,4-cyclohexanedimethanol, 1,2-cyclohexanediol, and 1,4-cyclohexanediol. These may be used alone or two or more of them may be used in combination.

Examples of the high molecular weight diol include, for example,
Polyethylene glycol, polypropylene glycol,
Examples include polytetramethylene glycol, polyhexamethylene glycol, poly (ethylene glycol-tetramethylene glycol) copolymer, and poly (ethylene glycol-propylene glycol) copolymer.

The number average molecular weight of the polyester component (B) is preferably from 500 to 5,000, more preferably from 5 to 5,000.
00 to 2000. When the number average molecular weight is less than 500, the blocking property of the polyester component (B) is reduced, the melting point is reduced, and the mechanical strength at a high temperature of the obtained elastomer may be reduced. On the other hand, if the number average molecular weight exceeds 5,000, the compatibility with the polyether component (A) decreases, the degree of polymerization of the obtained elastomer does not increase, and sufficient mechanical strength may not be obtained. The number average molecular weight of the polyester component (B) is a value corresponding to the average molecular weight of the polyester (b) described later.

The elastomer containing the polyether component (A) as a constitutional unit can be obtained by a known method. For example, an aromatic dicarboxylic acid or ester thereof may be combined with an excess of a low molecular weight diol in the presence of a catalyst such as, for example, tetrabutyl titanate, for example, at 160
It is obtained by conducting a transesterification reaction by heating to ~ 200 ° C and subsequently performing a polycondensation reaction by raising the temperature to 240 to 250 ° C under reduced pressure. If necessary, a high molecular weight diol may be added to the low molecular weight diol.

As the elastomer used in the present invention, in particular, a polyether component (A) bonded by a polyisocyanate component (C), or a polyether component (A) and a polyester component (B) are used. It is preferable to use those bonded by the isocyanate component (C).

The elastomer preferably contains a urethane binding component represented by the general formula (3) as the polyisocyanate component (C). —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 methylene group or an alkylene group and phenylene. Shows a compound bonded to a group.

Examples of the elastomer containing the urethane binding component represented by the above general formula (3) include those obtained by a polyaddition reaction between a compound having a hydroxyl group at a molecular terminal and an isocyanate compound. Examples thereof include urethane elastomers, polyetherester elastomers obtained by extending the chain with an isocyanate compound, and ester-based elastomers obtained by reacting polyether (a) and polyester (b) with polyisocyanate (c).

The structure of the polyisocyanate (c) is not particularly limited as long as it is a compound containing two or more isocyanate groups in the same molecule. As the polyisocyanate (c), those having an average number of isocyanate groups per molecule in the range of 2.0 to 2.2 are preferable.
Examples of the polyisocyanate (c) having an average number of isocyanate groups of 2.0 include aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, tolylene diisocyanate, phenylene diisocyanate, and naphthalene diisocyanate; 1,2-ethylene diisocyanate; 3-propylene diisocyanate, 1,4
-Butane diisocyanate, 1,6-hexamethylene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, isophorone diisocyanate, and aliphatic diisocyanates such as hydrogenated 4,4'-diphenylmethane diisocyanate.

Further, by mixing a polyisocyanate (c) having an average number of isocyanate groups of 2.0 with a polyisocyanate (c) having an average number of isocyanate groups exceeding 2.2, the average number of isocyanate groups per molecule is set to 2. It is preferable to use one having a range of 0 to 2.2.

A typical example of the isocyanate compound having an average number of isocyanate groups per molecule of more than 2.2 is polymeric MDI. As a commercial product, for example, "Millionate MR200" manufactured by Nippon Polyurethane Industries, Ltd.
(Average isocyanate group number 2.8), triphenylmethane triisocyanate (average isocyanate group number 3.
0), tris (isocyanatephenyl) thiophosphate (average number of isocyanate groups: 3.0), hexamethylene triisocyanate (average number of isocyanate groups: 3.0).
0) and the like.

To produce the above elastomer, the constituent components polyether (a), polyester (b) and polyisocyanate (c) are used. As these polyether (a), polyester (b) and polyisocyanate (c), those mentioned in the description of polyether component (A), polyester component (B) and polyisocyanate component (C) are used. Can be

The molar amount of the isocyanate group in the polyisocyanate (c) is a ratio of the molar amount of the active hydrogen-containing group (group capable of reacting with the isocyanate group) contained in the polyether (a) and the polyester (b). (Isocyanate group / group containing active hydrogen capable of reacting with isocyanate group) is preferably 0.8 to 1.05, more preferably 0.9 to 1.01. If the molar ratio is less than 0.8, the molecular weight of the obtained elastomer may decrease, and sufficient mechanical strength may not be obtained. On the other hand, if the molar ratio is more than 1.05, unstable by-products such as allophanate groups or burette groups are increased in the elastomer, and the moldability of the obtained elastomer is deteriorated, The decrease may be significant.

The above-mentioned elastomer, in which the polyether component (A) and the polyester component (B) are bound by the polyisocyanate component (C), is reacted at the both ends with the polyether (a) and the polyisocyanate (c). It is preferably produced by a two-step reaction including a first step of obtaining an isocyanated prepolymer and a second step of reacting the prepolymer with a polyester (b) having hydroxyl groups at both ends.

In the first step, the ratio of the molar amount of the isocyanate group contained in the polyisocyanate (c) to the molar amount of the group containing active hydrogen capable of reacting with the isocyanate group contained in the polyether (a) is , 1.1 to 2.2, more preferably 1.2 to 2.0. If the molar ratio is less than 1.1, both ends of the resulting prepolymer cannot be completely isocyanated, which may hinder the reaction in the second step. When the molar ratio exceeds 2.2, unreacted polyisocyanate (c) remains, so that a side reaction occurs during the reaction in the second step, and a secondary reaction such as an allophanate group or a burette group occurs. The amount of reaction products increases, which may cause a decrease in the moldability of the resulting elastomer or a decrease in physical properties over time.

The reaction temperature in the first step is 100 to 2
40 ° C is preferable, and more preferably 160 to 220 ° C. If the reaction temperature is lower than 100 ° C., the reaction may not proceed sufficiently. If the reaction temperature is higher than 240 ° C., the polyether (a) may be decomposed.

In the second step, the prepolymer produced in the first step is reacted with the polyester (b). here,
The ratio of the molar amount of isocyanate groups contained in the polyisocyanate (c) to the total molar amount of groups containing active hydrogen capable of reacting with the isocyanate groups contained in the polyether (a) and the polyester (b) is 0. 0.8 to 1.05, more preferably 0.9 to 1.01. By setting the molar ratio in the above range, side reactions hardly occur, the molecular weight of the obtained elastomer is increased, and the physical properties are also excellent.

The reaction temperature in the second step is from 100 to 2
40 ° C is preferable, and more preferably 160 to 220 ° C. If the reaction temperature is lower than 100 ° C., the reaction may not proceed sufficiently. If the reaction temperature is higher than 240 ° C., the prepolymer may be decomposed and an elastomer having sufficient strength may not be obtained. Here, the polyester (b) may be separately melted by heating and then added to the prepolymer using a pump or the like, or the polyester (b) may be superheated and melted by an extruder, and then the prepolymer may be added. Good.

The reaction for obtaining the elastomer is preferably a bulk reaction because the reactivity in the second step is particularly improved. As the reaction equipment, a single-screw or twin-screw extruder is used, and a co-rotating twin-screw extruder or a different-rotating twin-screw extruder is preferred, and more preferably, from the viewpoint of efficiency such as stirring and mixing. Is a co-rotating meshing twin screw extruder. The use of this equipment improves the reactivity especially in the second step. In order to continuously perform the reaction between the first step and the second step, it is preferable to use a tandem type extruder.

A catalyst may be used at the time of the above stirring and mixing. , Triethyleneamine, diethyleneamine, triethylamine, metal salts of naphthenic acid, metal salts of octylic acid, triisobutylaluminum, tetrabutyltitanate, calcium acetate, germanium dioxide, antimony trioxide and the like. These may be used alone or in combination of two or more.

As described above, the prepolymer having both ends isocyanated, which is obtained by reacting polyether (a) with polyisocyanate (c), is reacted with polyester (b) having hydroxyl groups at both ends. The polyether component (A) and the polyester component (B) are surely linked to the polyisocyanate component (C) without the chain extension of the polyether (a) and the polyester (b) alone by the polyisocyanate (c). An elastomer comprising the linked block copolymer is obtained. Further, the polyether (a) and the polyester (b) are partially reacted with the prepolymer and the polyester (b).
An elastomer can be obtained even when the compatibility between the polyether (a) and the polyester (b) is poor.

By controlling the equivalent ratio of the polyether (a), the polyester (b) and the polyisocyanate (c), for example, in the second step, an excess polyester (b) is reacted with the prepolymer. Thereby, the terminal of the obtained elastomer can be changed to the polyester (b). Such a reaction makes it possible to increase the melting point, and improves the moldability and high-temperature properties of the obtained elastomer.

A stabilizer may be added to the elastomer. Examples of the stabilizer include 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-).
4-hydroxybenzyl) benzene, 3,9-bis @ 2
-[3- (3-tert-butyl-4-hydroxy-5-methylphenyl) -propionyloxy] -1,1-dimethylethyl {-2,4,8,10-tetraoxaspiro [5,
5] Hindered phenolic antioxidants such as undecane;
Tris (2,4-di-t-butylphenyl) phosphite, trilauryl phosphite, 2-t-butyl-α-
(3-t-butyl-4-hydroxyphenyl) -p-cumenylbis (p-nonylphenyl) phosphite, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, pentaery Heat stabilizers such as styryltetrakis (3-laurylthiopropionate) and ditridecyl 3,3'-thiodipropionate are exemplified.

The compounding of the stabilizer may be carried out at any stage during the production of the elastomer or during the formation of a film or sheet-like elastomer layer from the elastomer.

The elastomer layer may contain additives such as fibers, inorganic fillers, flame retardants, ultraviolet absorbers, antistatic agents, inorganic substances, and higher fatty acid salts, as long as practicality is not impaired.

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

As the above-mentioned ultraviolet absorber, for example, p-
t-butylphenyl salicylate, 2-hydroxy-4
-Methoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,4,5-trihydroxybutyrophenone, and the like. Examples of the antistatic agent include N, N-bis (hydroxyethyl). Examples thereof include an alkylamine, an alkyl allyl sulfonate, and an alkyl allyl sulfanate.

Examples of the inorganic substance include barium sulfate, alumina, and silicon oxide. Examples of the higher fatty acid salt include sodium stearate, barium stearate, and sodium palmitate.

Further, a thermoplastic resin, a rubber component and the like other than those described above may be added to the elastomer layer for the purpose of modification. Examples of the thermoplastic resin include polyolefin, modified polyolefin, polystyrene, polyvinyl chloride, polyamide, polycarbonate, polysulfone, and polyester. Examples of the rubber component include natural rubber, styrene-butadiene copolymer, polybutadiene, polyisoprene, acrylonitrile-butadiene copolymer, ethylene-propylene copolymer (EPM, EPDM), polychloroprene, butyl rubber, and acrylic rubber. And silicone rubber, urethane rubber, olefin-based thermoplastic elastomer, styrene-based thermoplastic elastomer, vinyl chloride-based thermoplastic elastomer, ester-based thermoplastic elastomer other than the above, and amide-based thermoplastic elastomer.

The multilayer flexible film or sheet of the present invention comprises:
For example, water-cooled or air-cooled co-extrusion inflation method,
After forming a film by a co-extrusion T-die method or the like, a method of stretching in a uniaxial or biaxial direction may be mentioned. When the thermoplastic resin layer is a microporous layer, a method of laminating the microporous thermoplastic resin film and the elastomer by an extrusion lamination method;
It can be obtained as a laminate of an elastomer layer and a microporous thermoplastic resin layer by, for example, a method of dry laminating the microporous thermoplastic resin film and the elastomer film. Among them, a method of stretching after forming a film by a water-cooled or air-cooled co-extrusion inflation method, a co-extrusion T-die method or the like is preferable because the thickness of each layer can be controlled relatively freely.

The multilayer flexible film or sheet of the present invention may be used alone, or may be used by laminating with a microporous film or cloth. The kind of the microporous film or the fabric is not particularly limited in the lamination method.

(Function) The multilayer flexible film or sheet of the present invention swells when immersed in water by providing at least one surface of the elastomer layer with a thermoplastic resin layer having a small coefficient of linear expansion when immersed in water. It becomes a film or sheet that is difficult to perform. By using a film having microporosity for the thermoplastic resin layer, high moisture permeability is imparted to the multilayer flexible film or sheet. In addition, the elastomer layer has a soft segment composed of a specific polyether component (A). Thereby, the affinity with water is increased, and the adsorption of water molecules is promoted. Further, when the elastomer has a specific glass transition temperature and a soft segment amount, the molecular mobility is enhanced, and the diffusion of water molecules is promoted. With such a molecular design, the elastomer layer has a very high moisture permeability, and the multilayer flexible film or sheet of the present invention is provided with a very high moisture permeability.

[0057]

Embodiments of the present invention will be described below. The number average molecular weight, acid value and hydroxyl value were measured by the following methods.・Number average molecular weight gel permeation chromatography (“HLC 80” manufactured by Tosoh Corporation)
20 series "). In addition, two "HFIP806M" manufactured by Shodex were used for the column.
Hexafluoroisopropanol (0.00
5N sodium trifluoroacetate) and polymethyl methacrylate as a standard.

After the acid value sample was dissolved in a benzyl alcohol / chloroform mixed solvent, neutralization titration was performed using a phenol red indicator to determine the acid value. After dissolving the hydroxyl value sample and succinic anhydride in a nitrobenzene / pyridine mixed solvent and reacting for 10 hours, the reaction solution is reprecipitated with methanol, and the acid value of the obtained reaction product is measured in the same manner as above. Performed to obtain a hydroxyl value.

Using a glass transition temperature viscoelastic spectrometer (“RSA-11” manufactured by Rheometric Scientific Effey),
Heating rate 3 ° C / min, frequency 1.6Hz, strain 0.05%
It measured on condition of.

The acid value and hydroxyl value of the polyether and the isocyanate value (NCO value) of the isocyanate were the values guaranteed by the manufacturer.

Synthesis of Elastomer 100 parts by weight of dimethyl terephthalate, 102 parts by weight of 1,4-butanediol, 0.3 parts by weight of tetrabutyl titanate as a catalyst, and 1,3,5-trimethyl-2,2 as a stabilizer 0.3 parts by weight of 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 are added. After that, the reaction system was heated to 200 ° C under nitrogen.
For 3 hours to carry out a transesterification reaction. The progress of the transesterification reaction was confirmed by measuring the amount of methanol distilled off.

After the transesterification progresses, 240 minutes
The temperature was raised to 0 ° C., and a pressure reduction operation was performed. Reaction system is 2 in 15 minutes
The degree of pressure reduction reached 67 Pa or less. As a result of a polycondensation reaction for 10 minutes in this state, 112 parts by weight of white polyester was obtained. When the number average molecular weight, the acid value and the hydroxyl value of this polyester were measured by the above-described methods, the number average molecular weight was 2000, 5.0 (μeq / g) and 1 respectively.
000 (μeq / g). This is designated as polyester (b).

The polyether (a) has a number average molecular weight of 1
000, acid value 0 (μeq / g) and hydroxyl value 2000
(Μeq / g) 300 parts by weight of polyethylene glycol (all values guaranteed by the manufacturer) and 8,7.5 as a polyisocyanate (c) having an NCO value of 8000 (μeq / g) (4,4′-diphenylmethane diisocyanate guaranteed by the manufacturer). Parts by weight and a twin screw extruder (manufactured by Toshiba Machine Co., Ltd., L
/ D = 58) from the first barrel of the extruder.
100 parts by weight of the above polyester (b) is supplied from a barrel using a forced side feeder and melt-kneaded at 200 ° C., containing 62% by weight of a polyether component having a carbon / oxygen atomic ratio of 2.0, and a glass transition. An elastomer pellet having a temperature of −30 ° C. was obtained.

(Example 1) The elastomer synthesized above was used as the above-mentioned elastomer layer, and 50% by weight of a commercially available ester-based elastomer ("Hytrel 4067" manufactured by Du Pont-Toray Co., Ltd.) was used as the thermoplastic resin layer and the average particle size was 2.5 µm.
A mixture of 50% by weight of calcium carbonate surface-treated with a fatty acid of m is melt-kneaded by feeding to different extruders, and then co-extruded from a feed block die to form a film composed of three layers: Hytrel layer / elastomer layer / Hytrel layer A laminate was obtained. The film laminate was stretched three times in the longitudinal uniaxial direction to obtain a multilayer flexible film having a thickness of 30 μm and a layer ratio of each layer of 2: 6: 2.

Example 2 70% by weight of a commercially available ester-based elastomer ("Hytrel 4067" manufactured by Du Pont-Toray Co., Ltd.) as a thermoplastic resin layer and 30% by weight of calcium carbonate surface-treated with a fatty acid having an average particle size of 2.5 μm In the same manner as in Example 1 except that the mixture of the above was used, a multilayer flexible film having a stretching ratio of 3 in the longitudinal uniaxial direction, a thickness of 30 μm, and a layer ratio of each layer of 2: 6: 2 was obtained.

Comparative Example 1 Example 1 was repeated except that only a commercially available ester elastomer (“Hytrel 4067” manufactured by Du Pont-Toray Co., Ltd.) was used as the thermoplastic resin layer.
In the same manner as above, the stretching ratio in the longitudinal uniaxial direction is 3 times, and the thickness is 30 μm.
m, and a multilayer flexible film having a layer ratio of 2: 6: 2 was obtained.

Comparative Example 2 A single-layer microporous film ("NF Sheet, NG Good" manufactured by Tokuyama Corporation) was used.

The multilayer flexible films and the single-layer films obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were evaluated for the following properties. The results are shown in Table 1.

(1) Dimensional change rate (%) A 100 mm square was written on the film surface, the film was immersed in water at 23 ° C. for 24 hours, taken out of the water, and the diagonal length of the square immediately after being taken out was measured. did. Next, the dimensional change rate is calculated by substituting the average value L of the lengths of the diagonal lines into the following equation. Dimensional change rate (%) = [(L-141.4) / 141.
4)] × 100 The dimensional change rate of the thermoplastic resin layer alone is Hytrel 4
067 was measured on a 100 μm thick film obtained by press molding.

(2) Moisture Permeability Measurement was performed on a multilayer flexible film and a single-layer film in accordance with JIS Z 0208.

(3) Water resistance The water resistance test according to JIS L 1092 (Method B) was conducted by visual observation under a constant water pressure of 0.2 MPa for the presence or absence of leakage in accordance with the high pressure method.

[0072]

[Table 1]

[0073]

The multilayer flexible film or sheet of the present invention has the above-mentioned constitution, and uses an elastomer having high affinity with water, excellent molecular mobility and good flexibility as the elastomer layer. Accordingly, it has good flexibility, very high moisture permeability and resistance to water penetration, and has a small dimensional change rate when immersed in water.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4C098 AA09 CC03 DD06 DD22 DD24 DD26 4F100 AA01B AA01C AK01B AK01C AK54A AL05B AL05C AL09A BA02 BA03 BA06 BA07 EH20 EH202 EJ38 EJ382 GB23 GB66 GB72 JA05A JB06J4 J04A04B DA01 DB04 DB07 DF01 DF16 DF21 DF22 DG02 DG03 DG04 DG06 DG08 DG09 HA01 HA02 HA07 HA08 HB03 HB15 HC03 HC12 HC13 HC17 HC22 HC46 HC52 HC61 HC64 HC65 HC67 HC71 HC73 JA42 KA01 KB02 KC07 KC13 KC16 K03Q18 Q18 K18 K18 Q18 K18 Q18 K18

Claims (4)

[Claims] 1. A multilayer flexible film or sheet in which a thermoplastic resin layer other than the elastomer is laminated on at least one surface of an elastomer layer.
Is 3,000 (g / m ² ·
24 hours) or more, and the dimensional change when immersed in water for 24 hours is 10% or less. 2. The thermoplastic resin layer other than the elastomer laminated on at least one surface of the elastomer layer has a dimensional change rate of 10% or less when immersed in water for 24 hours, and the thermoplastic resin layer is fine. The multilayer flexible film or sheet according to claim 1, wherein the multilayer flexible film or sheet is formed from a porous layer. 3. The multilayer flexible film according to claim 1, wherein the thermoplastic resin layer other than the elastomer laminated on at least one surface of the elastomer layer contains 20 to 70% by weight of an inorganic substance. Sheet. Wherein the elastomeric layer comprises a thermoplastic elastomer as constituent units polyether component, a polyoxyalkylene group constituting the polyether component (-C _n
H2nO- ) has a carbon / oxygen atom ratio of 2.0 to 2.5, a polyether component in the thermoplastic elastomer of 50 to 95% by weight, and a glass transition temperature of the thermoplastic elastomer of- The multilayer flexible film or sheet according to any one of claims 1 to 3, wherein the temperature is 20 ° C or lower.