JPH0453842A - Production of porous sheet-like substance with low water absorption capacity - Google Patents

Abstract

PURPOSE:To obtain a porous sheet-like substance with a lower water absorption capacity by impregnating and/or coating a fibrous base with a water-in-oil type organic solvent/water dispersion of polyurethane, followed by specific procedures. CONSTITUTION:A fibrous base is impregnated and/or coated with a water-in-oil type organic solvent/water dispersion of polyurethane (e.g. a mixture of a reaction product of polytetramethylene glycol, ethylene glycol and diphenylmethane diisocyanate and a product obtained by reacting polypropylene glycol and diphenylmethane diisocyanate, followed by a reaction with ethylene glycol). The organic solvent is distilled off from the dispersion to gel the dispersion to thereby obtain a porous sheet-like substance. In the above process, as a dispersion, use is made of one that contains a water-and oil--repellent [e.g. one obtained from CF3(CF2)nCH2CH2OCOCH=CH2 (where n is 5 to 11; 9 on average), stearyl acrylate and N--methylolacrylamide].

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing a porous sheet material with low water absorption.

[Conventional technology]

As a highly productive method for manufacturing porous sheet materials,
A generally known method is to impregnate and/or apply a water-in-oil organic solvent-water dispersion of polyurethane onto a fiber base material, and then evaporate the organic solvent from the dispersion to form a gel. JP-A-48-4380, JP-A-54-6
6961, JP 54-68498, JP 58-194926, JP 61-72032
(Japanese Patent Application Laid-open No. 61-72033).

[Problem to be solved by the invention]

However, in the above production method, no porous sheet-like material having a significantly low water absorption rate has been obtained.

[Means to solve the problem]

Therefore, in view of the above circumstances, the inventors of the present invention have conducted intensive studies on a method for obtaining a porous sheet-like material with a significantly low water absorption rate. It was discovered that a porous sheet-like material obtained by the above method using a water-in-oil type organic solvent-water dispersion of polyurethane contained therein had a significantly low water absorption rate, and the present invention was completed.

That is, the present invention impregnates and/or coats a fiber base material (B) with a water-in-oil organic solvent-water dispersion of polyurethane (A), and then evaporates the organic solvent (C) from the dispersion. A method for producing a porous sheet-like material by at least gelling the material, characterized in that a dispersion containing a water- and oil-repellent (D) is used as the dispersion; and hydrophilic polyurethane polymer (A1)
Or polymer (AI) and hydrophobic polyurethane polymer (A
After impregnating and/or coating the fiber base material (B) with a water-in-oil type organic solvent-water dispersion of the mixture with 2), the organic solvent (C) is evaporated from the dispersion to form a gel. The present invention provides a method for producing a porous sheet-like material, characterized in that a dispersion containing a water- and oil-repellent (D) is used as the dispersion. be.

The water and oil repellent (D) that can be used in the present invention is not particularly limited (any known and commonly used agent can be used. The water and oil repellent CD) is usually fluorine-based. Examples of the water and oil repellent (D) include esters and polyesters obtained from TLF perfluoroalkyl group-containing alcohols or perfluoroalkylene group-containing polyhydric alcohols and carboxylic acids, and perfluoroalkyl group-containing alcohols or perfluoroalkylene groups. Urethane and polyurethane obtained from polyhydric alcohol and incyanate,
Examples include polymers and copolymers of ethylenically unsaturated monomers containing perfluoroalkyl groups or ethylenically unsaturated monomers containing perfluoroalkylene groups.

For example, general formula (I) R,A-OCC=CH, (I) R3 However, R is a perfluoroalkyl group having 4 to 20 carbon atoms, R3 is -H or -CH, A is -Q- -CON(Rx)-Q- -30. N(R,)-Q (However, -〇- is an alkylene group having 1 to 1 degrees of carbon atoms, and R2 is an alkyl group having 1 to 4 carbon atoms.) Examples include homopolymers of unsaturated monomers and copolymers of ethylenically unsaturated monomers containing perfluoroalkyl groups and ethylenically unsaturated monomers containing no perfluoroalkyl groups.

As the perfluoroalkyl group-containing ethylenically unsaturated monomer, for example, A-1: CFs(CFi)-CHaCHzOCOCH
=CH2 (n=5-11.Average of n=9) A-2: CF, (CF, ), CH, CH, 0COC (
CHI)=CH.

A-3: CFs(CFi)icHscHzOcOc(
CHs)=CH2A-4: (CFx)zcF(CFz
)s(CHz)sOcOctocHzA-5: (CFi
)zcF(CFz)to(CHz)xOcOcH=cH
zA-6: CF, (CF2)? 502N (C, H?)
CH, CH20COCH=CH.

A-7: CF3(CFri, S0.N(CH,)CH
ICH20COC(CHI)=CHIA-8: CF
s(CFi)ysOJ(CHx)CHzCH*0COC
H=CHxA 9: CF=(CFi)-(C
Hi) 40COCH=CH-A-10: CF, (C
F, ), COOCH=CH.

A-11: CFs (CFri7SOJ(C4HI)(
CHI), 0COCH=CH2A-12: CF, (
CF,)ycH,cH(OH)CH,0COCH=CH
.

A-13: CF, (CFri, C0N(C,H,)C
H,CH,0COC(CHI)=CH2A-14:
CFm(CFz)7CON(CJs)CHzCHzOC
Examples include monomers such as OCH=C)lx.

Ethylenically unsaturated monomers containing no perfluoroalkyl group are not particularly limited, but include, for example, ethylene, propylene, vinyl chloride, vinylidene chloride, styrene, α-methylstyrene, vinyl acetate, methyl (meth)acrylate,
Ethyl (meth)acrylate, n-butyl (meth)acrylate, 1so-butyl (meth)acrylate, te
rt-butyl (meth)acrylate, hexyl (meth)
Acrylate, n-octyl (meth)acrylate, 2
- Ethyl to bovine syl (meth)acrylate, stearyl (
meth)acrylate, benzyl(meth)acrylate,
Cyclohesyl (meth)acrylate, inbornyl (
meth)acrylate, dicyclopentanyl (meth)acrylate, dicyclopentenyl (meth)acrylate,
Methyl vinyl ether, propyl vinyl ether, octyl vinyl ether, butadiene, isoprene, chloroprene, 2-hydroxyethyl (meth)acrylate,
(meth)acrylic acid, (meth)acrylamide, N
-methylol(meth)acrylamide, 3-chloro-2
- Monomers such as hydroxy (meth)acrylate and diacetone acrylamide are exemplified.

If an ethylenically unsaturated monomer containing a higher alkyl group such as stearyl (meth)acrylate or isostearyl (meth)acrylate is used in combination with an ethylenically unsaturated monomer that does not contain a perfluoroalkyl group, water repellency can be further improved. There is a tendency that when an ethylenically unsaturated monomer containing a blocked incyanate group is used in combination, the abrasion resistance of the water and oil repellent effect is improved.

When the perfluoroalkyl group-containing ethylenically unsaturated monomer used in the present invention is copolymerized with the perfluoroalkyl group-free ethylenically unsaturated monomer, the copolymerization ratio of the monomers on both sides is Although not particularly limited, when the total of the normal side monomers is 100 parts by weight, the amount of the perfluoroalkyl group-containing ethylenically unsaturated monomer used is 30 to 9 parts by weight.
0 parts by weight, preferably 50 to 90 parts by weight.

Further, as another example of the water and oil repellent (D) that can be used in the present invention, for example, general formula (II) (R, -A-OCN), -U- where R1 has 4 carbon atoms ~20 perfluoroalkyl groups, A is -Q-C0N(Ra) Q- -3o, N(R1)-Q-1 (however, -Q- is an alkylene group having 1 to 10 carbon atoms, R2 is a carbon R1 is an alkyl group having 1 to 20 carbon atoms, a is an integer of 1 to 4, and b is an integer of 2 to 4.

Examples include perfluoroalkyl group-containing urethane adducts represented by:

Examples of such perfluoroalkyl group-containing urethane adducts include: U-4: CsF 1tS(hN(CJs)CHzC)Iz-°0
°NH(□1″“ゞ”C00CH, Su MH, CH・0”
・And so on.

The form of the water and oil repellent (D) is not particularly limited, and may include an organic solvent solution, an organic solvent dispersion, an aqueous solution, an aqueous dispersion,
Any form of organic solvent-water dispersion can be used. However, even if the same weight of water and oil repellent (D) is used as an oil-in-water emulsion and as an organic solvent solution, the oil-in-water emulsion is better than the oil-in-water emulsion, even if the same weight is used per solid content of polyurethane.
This is preferable because the resulting porous sheet-like material has a lower water absorption rate. Water and oil repellent (as an oil-in-water emulsion)
If you want to obtain the same level of water absorption as the porous sheet-like material obtained using D) using the water and oil repellent (D) as an organic solvent solution, the water and oil repellent used as an oil-in-water emulsion should be used. It is necessary to use a water and oil repellent (D) with a solid content weight that is 2 to 3 times the solid content weight of the oil agent (D).

Any conventionally known method can be used to form the water and oil repellent (D) into an oil-in-water emulsion.

For example, a method of emulsion polymerization of a perfluoroalkyl group-containing ethylenically unsaturated monomer in the presence of an emulsifier, or a method of pre-producing a monomer of perfluoroalkyl group-containing ethylenically unsaturated monomers or a perfluoroalkyl group-containing urethane adduct. Then, a method of forcibly emulsifying it in water using an emulsifier can be mentioned.

The amount of the water and oil repellent (D) used in the present invention is not particularly limited, but the solid content of the water and oil repellent (D) is usually 0 per 100 parts by weight of the solid content of the polyurethane (A) described below.
．． It is preferably 0.1 to 10 parts by weight, especially 0.1 to 3 parts by weight when added as an emulsion.
When added as an organic solvent solution, 0.3 to Qfi parts is more preferable.

The present invention provides water-in-oil organic solvents for polyurethane (A).
A method for manufacturing a porous sheet-like material by impregnating and/or applying an aqueous dispersion onto a fiber base material (B), and then evaporating the organic solvent (C) from the dispersion to gel it. This is a method for producing a porous sheet material, characterized in that a dispersion containing a water and oil repellent (D) is used as a dispersion.

The water-in-oil organic solvent-water dispersion of polyurethane (A) that can be used in the present invention is not particularly limited, but is usually prepared by adding water to an organic solvent solution of polyurethane (A) and dispersing it. is used.

In the present invention, the polyurethane (A) is a hydrophilic polyurethane polymer (A1) and a hydrophobic polyurethane polymer (A1).
It is preferable that polyurethane (A) has a hydrophilic polyurethane polymer (A1) as an essential component. ), and the polymer (A1) and the polymer (A2
) and the total amount is 100 parts by weight, the polymer (Al)
Particularly preferred is a mixture of 10 to 90 parts by weight and 90 to 10 parts by weight of polymer (A2).

As the polyurethane (A), any known and commonly used polyurethane can be used. Polyurethane (A) can be easily obtained by using, for example, a diol and a diisocyanate as essential components, and optionally using a trifunctional or higher functional alcohol, a monoalcohol, a trifunctional or higher functional isocyanate, a monoisocyanate, or the like.

The method for producing polyurethane (A) is not particularly limited, but examples include: (1) reacting a diisocyanate and a diol; (2) reacting a diisocyanate and a diol to produce a urethane prepolymer with terminal isocyanate groups; Alternatively, a method of reacting with a diamine can be mentioned.

Examples of diisocyanates that can be used in producing the polyurethane (A) that can be used in the present invention include 2,4-1-lylene diisocyanate, 2,6-lylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate,
4. 4'-diphenylmethane diisocyanate, 2
, 4''-diphenylmethane diisocyanate, 2.
2'-diphenylmethane diisocyanate, 3. 3
'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dimethoxy-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4,4
'-biphenylene diisocyanate, 1. 5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1, 3-cyclohexylene diisocyanate, l.

4-cyclohexylylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate), 4.
4'-dicyclohexylmethane diisocyanate, 3
．． Examples include 3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate.

For convenience, the diol used in the production of the polyurethane (A) used in the present invention has an average molecular weight of j1300 to 1.
It is divided into high molecular weight diols having a molecular weight of 0,000, preferably 500 to 5,000, and low molecular weight diols having a molecular weight of 300 or less.

Examples of the polymer diol include polyester diol, polyether diol, polycarbonate diol, polyacetal diol, polyacrylate diol, polyester amide diol, polythioether diol, and the like.

As polyester diol, ethylene glycol,
Propylene glycol, 1,3-propanediol, 1
, 4-butanediol, 1,5-pentanediol, 3
-Methyl-1,5-bentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol (molecular weight 300-6.
000), dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-
Cyclohexanediol, 1゜4-cyclohexane dimetatool, bisphenol A1, hydrogenated bisphenol A1, glycol components such as hydroquinone and their alkylene oxide adducts, succinic acid, adipic acid,
Azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1. 3-cyclopencune dicarboxylic acid, 1. 4-cyclohexane dicarbonic acid,
Terephthalic acid, isophthalic acid, phthalic acid, 1. 4-naphthalene dicarboxylic acid, 2,5-naphthalene dicarboxylic acid, 2,6-naphthalene dicarboxylic acid, naphthalic acid, biphenyl dicarboxylic acid, 1,2-bis(phenoxy)ethane-p, p' dicarboxylic acid and these dicarboxylic acids Anhydride or ester-forming derivative; polyester obtained by dehydration condensation reaction with an acid component such as p-hydroxybenzoic acid, p-(2-hydroxyethoxy)benzoic acid, and ester-forming derivatives of these hydroxycarboxylic acids. Other examples include polyesters obtained by ring-opening polymerization of cyclic ester compounds such as ε-caprolactone, and copolyesters thereof.

Examples of polyether diol include ethylene glycol,
Diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-
Butanediol, 1,4-butanediol, 19.6-
2 active hydrogen atoms such as hegyosandiol, neopentyl glycol, ethylenediamine, dihydroxybenzoic acid, etc.
Ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin,
Examples include those obtained by addition polymerization of one or more monomers such as tetrahydrofuran and cyclohexylene by a conventional method.

Examples of the polycarbonate diol include compounds obtained by reacting glycols such as 1.4-butanediol, 1.6-hexanediol, and diethylene glycol with diphenyl carbonate and phosgene.

The diols and diamines used in the method for producing polyurethane in (2) above include diols with a molecular fi of 300 or less, such as the glycol component used as a raw material for polyester diol, ethylenediamine, 1,6-hexamethylenediamine, piperazine, 2. 5-dimethylpiperazine, isophoronediamine, 4. 4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-
Amine compounds such as dicyclohexylmethanediamine, 1,4-cyclohexanediamine, 1,2-propanediamine, hydrazine, diethylenetriamine, and triethylenetetramine are mentioned.

The hydrophobic polyurethane polymer (A2) can be easily produced, for example, from the above raw materials. In addition to the above-mentioned raw materials, the hydrophilic polyurethane polymer (A1) may further contain an active hydrogen-containing compound that has a hydrophilic atomic group or an atomic group that can become hydrophilic through neutralization and that can react with isocyanate groups. It can be easily manufactured by Examples of active hydrogen-containing compounds that have such hydrophilic atomic groups or atomic groups that can become hydrophilic through neutralization and that can react with isocyanate groups include 2-oxyethanesulfonic acid, phenolsulfonic acid, and sulfobenzoic acid. acids, sulfonic acid-containing compounds such as sulfophuccinic acid, 5-sulfoisophthalic acid, sulfanilic acid, 1゜3-phenylenediamine-4,6-disulfonic acid, 2,4-diaminotoluene-5-sulfonic acid, and derivatives thereof. is a polyester polyol obtained by copolymerizing these; 2,2-dimethylolpropionic acid, 2
, 2-dimethylolbutyric acid, 2.2-dimethylolvaleric acid, dioxymaleic acid, 2.6-dioxybenzoic acid, 3
, 4-diaminobenzoic acid and other carboxylic acid-containing compounds and their derivatives, or polyester polyols obtained by copolymerizing these; containing at least 30% by weight or more of ethylene oxide repeating units, and containing at least one active unit in the polymer. Molecules containing hydrogen! Examples include nonionic group-containing compounds such as polyoxyethylene-polyoxyalkylene copolymers having a molecular weight of 300 to 10,000, or polyester polyether polyols obtained by copolymerizing these, which may be used alone or in combination. .

During the production of polyurethane (A) or
As the organic solvent used in preparing the water-in-oil type organic solvent-water dispersion, any known and commonly used organic solvent can be used. Examples of organic solvents include methyl ethyl ketone, methyl propyl ketone, methyl isobutyl ketone, dimethyl ketone, methyl formate, ethyl formate, propyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, acetone, tetrahydrofuran, dioxane, benzene, Examples include toluene, hexane, dichloroethane, etc., and these can be used alone or in combination of two or more. The organic solvent is preferably an organic solvent having a boiling point of 120° C. or less and a water solubility of 1 to 50 g per 100 g of organic solvent at 25° C., and methyl ethyl ketone is particularly preferable.

The amount of water used in preparing a water-in-oil organic solvent-water dispersion of polyurethane (A) is not particularly limited, but is usually 50 parts by weight or more per 100 parts by weight of solid content of polyurethane (A). Of course, the amount of water to be used is preferably selected appropriately depending on the solid content concentration of the water-in-oil organic solvent-water dispersion of polyurethane (A), the temperature and humidity of the atmosphere during sheet production, which will be explained later.

In addition to the above-mentioned water and oil repellent (D), the water-in-oil organic solvent-water dispersion of polyurethane (A) used in the present invention is used to further improve the abrasion resistance, tactile feel, and texture of the sheet. Other polymers or condensates may be added as necessary. Examples of such polymers and condensates include emulsions such as vinyl acetate, ethylene vinyl acetate, acrylic, and acrylic styrene; styrene/butadiene, acrylonitrile, and
Latexes such as butadiene type and acrylic/butadiene type; ionomers such as polyethylene type and polyolefin type; polyurethane, polyester, polyamide, epoxy type resin, cellulose acetate, ethyl cellulose, and butyl cellulose.

The present invention further requires additives such as dyes, pigments, surfactants, softeners, crosslinking agents, stabilizers, flame retardants, fillers, etc. to the water-in-oil organic solvent-water dispersion of polyurethane (A). It may be added and used depending on the situation.

In the method for producing a porous sheet material of the present invention, a water-in-oil organic solvent-water dispersion of polyurethane containing a water- and oil-repellent (D) is impregnated and/or applied to a fiber base material (B). Thereafter, the organic solvent (C) is evaporated from the dispersion to form a gel, thereby producing a porous sheet material. A porous sheet-like material is formed when the organic solvent evaporates and becomes a gel, so no further operations are required, but usually water is further evaporated after the organic solvent (C) is evaporated to form a sheet. is often dried.

The fiber substrate (B) to be impregnated and/or coated is
There are no particular limitations, but for example, known and commonly used knitted and woven fabrics, non-woven fabrics,
Examples include short fibers. These base materials may be subjected to water-repellent or oil-repellent treatment in advance.

The method of impregnating and/or coating the fiber base material (B) with a water-in-oil organic solvent-water dispersion of polyurethane (A) containing the water and oil repellent (D) is not particularly limited, but for example, Various conventional methods such as coating, spraying, dipping, etc. can be employed.

Although the conditions for evaporating the organic solvent (C) are not particularly limited, it is preferable to evaporate the organic solvent (C) more selectively while leaving as much water as possible. The conditions for more selectively evaporating the organic solvent (C) are as follows:
It is preferable to select it appropriately depending on the boiling point, vapor pressure, etc.

For example, organic solvents with high vapor pressure and lower boiling points than water (
When C) is used, the organic solvent (C) may be evaporated at a temperature below the boiling point of water, and when an organic solvent (C) with a low vapor pressure and a relatively high boiling point is used, The organic solvent (C) may be evaporated in a high humidity atmosphere.

The temperature when evaporating the organic solvent (C) is -80℃ for boat fishing.
The temperature is preferably at least 10°C lower than the boiling point of the organic solvent (C) having the lowest boiling point in the water-in-oil organic solvent-water dispersion of the polyurethane (A) at a temperature of at least 10°C. Such a temperature is particularly preferable because not only can evaporation of water be easily suppressed and the organic solvent (C) can be selectively evaporated, but also a porous sheet-like material with small pore diameter and excellent surface condition can be obtained.

The time required to evaporate the organic solvent (C) is at least enough time for the polyurethane component in the water-in-oil organic solvent-water dispersion of the polyurethane (A) to coagulate.

The porous sheet-like material obtained by the production method of the present invention has an excellent low water absorption rate as it is because it contains a water and oil repellent (D), but if necessary, this sheet may be further added. A water and oil repellent (D) may be added.

The porous sheet-like material obtained by the production method of the present invention can be used as synthetic leather as it is or by bonding it to another base material. More specifically, clothing such as raincoats,
Various uses include shoes such as rain boots, bags, bicycle covers, waterproof fabrics for tents, filtration materials such as air conditioner filters and engine oil filters, wallpaper, flooring materials, canvas, and medical materials.

〔Example〕

Next, the present invention will be specifically explained with reference to Examples and Comparative Examples, where all parts and percentages are based on weight unless otherwise specified.

Synthesis example 1 Polyethylene adipate (molecule jll 710) 171
0 parts and 750 parts of diphenylmethane diisocyanate were allowed to react for 2 hours at IOO°C under a nitrogen stream, and then a mixture consisting of 170 parts of tetramethylene glycol, 3945 parts of methyl ethyl ketone, and 3.0 parts of triethylene diamine was added and reacted at 70°C for 10 hours. Further, 2198.7 parts of methyl ethyl ketone was added to obtain a polyurethane dispersion (PU-1) with a solid content of 30%.

Synthesis Example 2 Polytetramethylene glycol (molecular weight 1000) 10
00 parts, 93 parts of ethylene glycol and 625 parts of diphenylmethane diincyanate were added to 1 part of methyl ethyl ketone.
The reaction was completed for 8 hours at 60°C under a nitrogen stream, and then 2500 parts of methyl ethyl ketone was added to form a polyurethane dispersion (PU-2) with a solid content of 30%.
) was obtained.

Synthesis Example 3 1300 parts of polyethylene adipate (molecular weight 1625), 300 parts of polyethylene glycol (molecular weight 1500) and 750 parts of diphenylmethane diisocyanate were allowed to react at 100°C for 2 hours under a nitrogen stream, and then 170 parts of tetramethylene glycol and 3 parts of methyl ethyl ketone were added.
After adding a mixture of 780 parts and 3.0 parts of triethylenediamine and reacting at 70°C for 10 hours, 2107 parts of methyl ethyl ketone was further added to obtain a polyurethane dispersion (PU-3) with a solid content of 30%.

Synthesis example 4 Polypropylene glycol (molecular weight 2000) 4000
and 750 parts of diphenylmethane diisocyanate were allowed to complete the reaction at 80°C for 3 hours under a nitrogen stream, and then a mixture consisting of 2000 parts of polyethylene glycol (molecular weight 1000) and 2000 parts of methyl ethyl ketone was added,
After reacting at 70°C for 6 hours, 2500 parts of methyl ethyl ketone was further added to obtain a polyurethane solution (PU-4) with a solid content of 60%.

Synthesis Example 5 In a glass reaction vessel (inner volume 500 m1), A-14
4g, stearyl acrylate 34.4g, N
- 1.6 g of methylol acrylamide, 0.8 g of dodecyl mercaptan, 276.8 g of deionized pure water,
Acetone 40g1C+sHsmN(CHs)icl
1,6 g and CsH+yC,H40(CHsCH
. The obtained copolymer emulsion had a solid content concentration of 20
．． It was 0%.

A copolymer emulsion according to the present invention was synthesized in a similar manner, and its copolymerization ratio is shown in Table 1 together with the copolymerization ratio in Synthesis Example 5. In addition, in the table, STA is stearyl acrylate, EHMA is 2-ethylhexyl methacrylate, EHA is 2-ethylhexyl acrylate, MMA
is methyl methacrylate, CPMA is 3-chloro-2-
Hydrobovine dipropyl methacrylate, VCI is vinyl chloride, N-MAM is N-methylolacrylamide, OT
A is 2-hydroxyethyl acrylate/2.4-1-
Luene diisocyanate/methyl ethyl ketoxime = 1
/1/1 (mol) indicates the adduct.

Table 1 Synthesis Example 6 Perfluoroalkyl group-containing urethane adduct (U=1
) of 50% solution of methyl isobutyl ketone 400 gSC
+iHxiN(CHm)scl 4. Og.

CIH17C, H40 (CH2CH20), H (n=8
) 6,0 g and 590 g of water were kept warm at 60°C and 1
By performing homomixer treatment at 0,000 revolutions, a perfluoroalkyl group-containing urethane adduct emulsion (F-7) with a solid content of 20.0% was obtained.

Synthesis Example 7 After reacting 500 parts of polybutylene adipate (molecular weight 500), 500 parts of diphenylmethane diisocyanate and 200 parts of methyl ethyl ketone at 70°C under a nitrogen stream for 3 hours, C=F+ySOJ(C-Hy)CJ40H1
170 parts was added and reacted at 70°C for 6 hours, and then 1970 parts of methyl ethyl ketone was added to reduce the solid content to 5.
A perfluoroalkyl group-containing urethane oligomer solution (F-8) having excellent compatibility or miscibility with 0% polyurethane polymer was obtained.

Synthesis Example 8 In a glass reaction vessel (inner volume 500 m1), A-75
6g, stearyl methacrylate 24g1 dodecyl mercaptan 0.2g.

1.1.1-Trichloroethane (119.8 g) was added, and azobisisobutylnitrile (0.4 g) was added, followed by a copolymerization reaction at 70° C. for 12 hours with stirring under a nitrogen atmosphere.

Add 20% of 1.1.1-trichloroethane to the resulting viscous solution.
0g of copolymer solution (F-9) with a solid content of 20.0%.
) was obtained.

Synthesis example 9 A-756g, stearyl methacrylate 24g1
A copolymer emulsion (F-10
) was obtained.

Examples 1 to 15 and Comparative Examples 1 to 2 Polyurethane of Synthesis Examples 1 to 4, copolymer emulsion of Synthesis Example 5, urethane adduct emulsion of Synthesis Example 6,
The urethane oligomer solution of Synthesis Example 7, the copolymer solution of Synthesis Example 8, the copolymer emulsion of Synthesis Example 9, an organic solvent, and water were mixed in the proportions shown in Table 2 and stirred with a homomixer to form a milky white repellent. A water-in-oil organic solvent-water dispersion of polyurethane containing a water and oil repellent was prepared. This dispersion was impregnated into a nonwoven fabric made of polyester single fibers, and the solvent was immediately selectively evaporated at 80°C for 10 minutes.
It was dried at 0°C for 5 minutes. The properties of the porous sheet material thus obtained are shown in Table 2.

In addition, the water absorption rate in the table was measured according to the method of JIS K-6505, and the water vapor permeability was measured according to the method of JIS L-0208.

As described above, according to the present invention, a porous sheet material with extremely low water absorption can be obtained.

[Effect]

Although it is unclear why the porous sheet material obtained by the method of the present invention has extremely low water absorption, it is possible to impregnate and/or coat a base material with a water-in-oil type organic solvent aqueous dispersion of polyurethane. In the method of obtaining a porous sheet-like material by this method, not only the water and oil repellent agent and its organic solvent solution, but especially when the water and oil repellent agent is used as an emulsion, as a result of the emulsion existing in the water layer part. The water- and oil-repellent agent adheres not only to the surface of the pores in the porous film that is formed in the process of water evaporation, but also to the fiber surface of the base material, making the painting area water repellent, resulting in particularly excellent low water absorption. It is presumed that this is due to the fact that sex is obtained.

〔Effect of the invention〕

After impregnating and/or applying the water-in-oil type organic solvent-water dispersion of the polyurethane of the present invention to a fiber base material, the organic solvent is evaporated from the dispersion to form a gel. The porous sheet material obtained by the method for producing a porous sheet material characterized by using a dispersion liquid in the method for producing the porous sheet material has extremely low hygroscopicity, and
It has a particularly remarkable effect of having sufficient moisture permeability.

Claims (1)

[Claims] 1. After impregnating and/or coating a fiber base material (B) with a water-in-oil organic solvent-water dispersion of polyurethane (A), the organic solvent (C ) in a method for producing a porous sheet-like material by evaporating and gelling,
A method for producing a porous sheet material, characterized in that a dispersion containing a water and oil repellent (D) is used as the dispersion. 2. The manufacturing method according to claim 1, wherein the water and oil repellent (D) is a fluorine-based water and oil repellent. 3. The manufacturing method according to claim 1, wherein the water and oil repellent (D) is a fluorine-based water and oil repellent emulsion. 4. The production method according to claim 1, wherein the water and oil repellent (D) is an emulsion of an acrylic polymer having a perfluoroalkyl group and a blocked isocyanate group in one molecule. 5. The water and oil repellent (D) contains 50 to 90% by weight of an ethylenically unsaturated monomer containing a perfluoroalkyl group and 10 to 50% by weight of an ethylenically unsaturated monomer containing no perfluoroalkyl group.
The method according to claim 1, which is a copolymer emulsion with % by weight. 6. The manufacturing method according to claim 1, 2, 3, 4 or 5, wherein the solid content of the water and oil repellent (D) is used in an amount of 0.1 to 3 parts by weight per 100 parts by weight of the solid content of the polyurethane (A). 7. A water-in-oil organic solvent-water dispersion of the hydrophilic polyurethane polymer (A1) alone or a mixture of the polymer (A1) and the hydrophobic polyurethane polymer (A2) is added to the fiber base material (
In a method of manufacturing a porous sheet-like material by impregnating and/or applying B) and then evaporating the organic solvent (C) from the dispersion to gel it, as the dispersion,
A method for producing a porous sheet-like material, comprising using a dispersion containing a water and oil repellent (D). 8. The manufacturing method according to claim 7, wherein the water and oil repellent (D) is a fluorine-based water and oil repellent. 9. The manufacturing method according to claim 7, wherein the water and oil repellent (D) is a fluorine-based water and oil repellent emulsion. 10. The production method according to claim 7, wherein the water and oil repellent (D) is an emulsion of an acrylic polymer having perfluoroalkyl groups and blocked isocyanate groups in one molecule. 11. The water and oil repellent (D) contains 50 to 90% by weight of an ethylenically unsaturated monomer containing a perfluoroalkyl group and 10 to 5% of an ethylenically unsaturated monomer containing no perfluoroalkyl group.
The method according to claim 7, which is a copolymer emulsion with 0% by weight. 12. Claims 7, 8 and 9 in which 0.1 to 3 parts by weight of water and oil repellent solids are used per 100 parts by weight of polyurethane solids.
, 10 or 11.