JPH03239734A - Production of porous sheet material - Google Patents

Abstract

PURPOSE:To obtain a porous sheet material having good heat, scratch and weathering resistances by using a polyurethane emulsion comprising water and a polyurethane dispersion prepared by dispersing a polyurethane urea formed from an NCO-terminated urethane prepolymer and a cyclic diamine in a solution of a polyurethane resin in an organic solvent. CONSTITUTION:A process for producing a porous sheet material by coating or impregnating a substrate with a W/O polyurethane emulsion comprising a polyurethane polymer, an organic solvent and water and drying the substrate, wherein said emulsion comprises water and a polyurethane dispersion prepared by dispersing a polyurethane urea formed from an NCO-terminated urethane prepolymer A formed from an organic polyisocyanate, a polymer polyol and optionally a low-molecular polyol and a cyclic diamine B having an amino equivalent of at least 54 in a solution of a polyurethane resin C in an organic solvent. The polyurethane dispersion is desirably formed by reacting the prepolymer A with the diamine B in the solution of the resin C.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a method for manufacturing porous sheet materials.

[Prior Art] Many methods have been known to obtain porous sheet materials from polyurethane polymer solutions as substitutes for natural leather, and these methods can be broadly classified into wet methods and dry methods. Both methods have their advantages and disadvantages. The dry method is superior in terms of productivity. As such a dry method, a porous sheet material is known from a polyurethane emulsion made by reacting ethylene glycol and diphenylmethane diisocyanate (MDI) in a polyurethane resin solution (for example, JP-A-Sho E.
32-273236).

[Problems to be Solved by the Invention] However, the porous sheet material made from the above polyurethane emulsion has a problem of poor heat resistance, scratch resistance and weather resistance.

[Means for Solving the Problems] The present inventors have intensively studied porous sheet materials that are excellent in heat resistance, scratch resistance, and weather resistance, and as a result, have arrived at the present invention.

That is, the present invention provides a method for producing a porous sheet material in which a water-in-oil type polyurethane emulsion consisting of a polyurethane polymer, an organic solvent, and water is applied or impregnated onto a substrate and then dried. A urethane prepolymer (A) having a terminal NCO group made from a polyisocyanate, a high molecular polyol, and optionally a low molecular polyol, and an amine 7 group equivalent of at least 5
A porous material characterized by using a polyurethane dispersion obtained by dispersing and containing a polyurethaneurea from a cyclic diamine (B) having a polyurethane resin (B) in an organic solvent solution of a polyurethane resin (C), and a polyurethane emulsion consisting of water. This is a method for manufacturing sheet materials.

In the urethane prepolymer (A) having a terminal NCO group used in the present invention, the organic polyisocyanate is an aliphatic polyisocyanate such as hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1.6.11-undecanetri Isocyanate, 2.2.4-trimethylhexamethylene diisocyanate, lysine diisocyanate), 2J-diisocyanate methyl caproate, bis(2-isocyanateethyl) fumarate, bis(2-isocyanateethyl)carbonate, 2-incyanate Ethyl-2,6-
aqueous modified products of HDI and trimerized products of MDI; alicyclic polyisocyanates, such as 1-isocyanate-3-isocyanate methyl-3°5.5-)limethylcyclohexane (IPD);
I), cyclohexylmethane-4,4-diincyanate (hydrogenated MD I ), cyclohexylene diisocyanate), 1,3-diisocyanate methylcyclohexane (hydrogenated XDI), trimerized and hydrogenated IPDI M
Trimerized products of DI, etc.; Aroaliphatic polyisocyanates,
For example, xylylene diisocyanate, tetramethylxylylene diisocyanate, diethylbenzene diisocyanate, etc.; aromatic polyisocyanates, such as tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MD I )'t naphthylene diisocyanate, etc.; and modified products of these polyisocyanates. (carposiimide group, uretdione group, uretdione group, biuret group and/or incyanurate group-containing modified products, etc.) can be used. Among these, preferred are alicyclic polyisocyanates. Particularly preferred among the alicyclic polyisocyanates are IPDI and hydrogenated MDI.

Examples of high-molecular polyols include polyether polyols (low-molecular polyols (trifunctional polyols, evapoethylene glycol, propylene glycol, 1.3- or 1.
4-butanediol, 3-methylbentanediol, 1
．． 6-hexanediol, neopentyl glycol, diethylene glycol and cyclohexylene glycol: trifunctional or higher functional polyols such as glycerin, trimethylolpropane, pentaerythritol, sorbitol and sucrose), alkylene oxides of polyhydric phenols (bisphenols such as bisphenol A) [Alkylene oxide having 2 to 4 carbon atoms, such as one or more of ethylene oxide, propylene oxide, butylene oxide (random and/or block)] adduct, ring-opening polymer of alkylene oxide (such as polytetramethylene ether glycol) ), polyester polyols (polycarboxylic acids such as adipic acid, succinic acid, cepacic acid, azelaic acid, phthalic acid,
isophthalic acid and terephthalic acid) and low-molecular polyol or polyether polyol (such as the low-molecular polyol, triethylene glycol-polyethylene glycol, etc.). Polyester polyols, bolicaprolactone polyols, and polycarbonate polyols whose terminal ends are hydroxyl groups , polybutadiene polyols, hydrogenated polybutadiene polyols, acrylic polyols, polymer polyols [polyols made by polymerizing vinyl monomers (acrylonitrile, styrene, etc.) in polyols (such as the above-mentioned polyether polyols and polyester polyols)], and A mixture of two or more of these may be used.

Among the polymer polyols, preferred are polyether polyols, polyester polyols, polycaprolactone polyols and polycarbonate polyols.

The OH equivalent of the polymer polyol is usually 200 to 3000,
Preferably it is 250-2000.

Examples of the low-molecular polyol include those similar to the low-molecular polyols explained in the section on polyether polyols. The preferred low-molecular polyol is ethylene glycol! , 4-butanediol and bisphenol A with ethylene oxide and/or propylene oxide 2
~4 molar adduct.

The weight ratio of high molecular weight polyol and low molecular weight polyol is usually I
:0 to 1:5, preferably 1:0 to I:3.

When it exceeds 5, the porous sheet becomes hard and its scratch resistance deteriorates. Average OH of high molecular polyol and low molecular polyol
The equivalent is usually 150 to 2000, preferably 200 to 15
It is 00.

The average number of functional groups in the high-molecular polyol and low-molecular polyol is usually 2 to 3, preferably 2 to 2.5.

For producing polyurethane prepolymer (A),
The ratio of organic polyisocyanate to high-molecular polyol and, if necessary, low-molecular polyol can be varied, but the equivalent ratio of NCO to OH groups is usually 1.1:In2O.
:1, preferably 1.5:1 to 25:1.

In producing the urethane prepolymer, the organic polyisocyanate, the polymer polyol, and if necessary, the low molecular polyol may be reacted at once, or the reaction may be carried out in stages [a part of the polyol (for example, the polymer polyol) ) and an organic polyisocyanate, and then the remainder of the polyol (for example, a low-molecular-weight polyol)
A method in which a polyol and a part of an organic polyisocyanate are reacted to form a 08M-terminated prepolymer and then the remainder of the organic polyisocyanate is reacted, a method that combines these methods, etc.] You may.

The prepolymer formation reaction is usually carried out at 40 to 140°C, preferably εG-120°C.

The reaction may be carried out in a solvent (eg toluene, xylene, methyl ethyl ketone, etc.), and the solvent may be added during or after the reaction.

The total NCO group content of the urethane prepolymer (A) is usually 0.
It is 5 to 30%, preferably 1 to 25%.

The equivalent amount per active hydrogen (NH2, NH) that reacts with the amine 7 group equivalent CNC0 group used in the present invention] is at least 5
Examples of the cyclic diamine (B) having 4 include aromatic diamines (diphenylmethanediamine, dichlorodiphenylmethanediamine, tolylenediamine, diethyltolylenediamine, benzidine, phenylenediamine, etc.), alicyclic diamines [dicyclohexylmethane-4,4- diamine C hydrogenated MBA), 1,4-diaminocyclohexane,
4.4-Diamino-3,3'-dimethylcyclohexylmethane, l-amino-3-aminomethyl-3,5,5
-)limethylcyclohexane (IPDA), etc.], aromatic aliphatic diamines (xylylene diamine, tetramethylxylylene diamine, etc.), and mixtures of two or more of these. Among these, alicyclic diamines are preferred. Particularly preferred among the alicyclic diamines are hydrogenated MDI, 1,4-diaminocyclohexane and IPDI. If an amine other than the cyclic diamine (B) is used, such as a cyclic amine having an amine 7 equivalent of less than 54 (eg, piperazine), the porous sheet will become hard and the scratch resistance will deteriorate. In addition, when using a non-cyclic aliphatic amine (for example, hexamethylene diamine), the resulting porous sheet has a low melting point and poor heat resistance.

Further, cyclic diamine (B) and amines other than (B) can be used in combination, but it is preferably less than 50% of (B). 50%
If it exceeds this, the scratch resistance or heat resistance of the porous sheet will deteriorate. In addition, monoalcohols (
Methanol, ethanol, n-butamel) and monoamines (ethylamine, n-butylamine, di-n-butylamine, monoethanolamine, jetanolamine, etc.) can also be used.

Examples of the polyurethane resin (C) used in the present invention include linear polyurethanes made from organic diisocyanates, polymeric diols, low-molecular diamines, and, if necessary, low-molecular diols.

Examples of organic diisocyanates include aliphatic diisocyanates such as hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 2.2.4-)dimethylhexamethylene diisocyanate, lysine diisocyanate, etc.; alicyclic diisocyanates such as IPDI
, hydrogenated MDL cyclohexylene diisocyanate, hydrogenated XDI, etc.; aromatic aliphatic diisocyanates such as xylylene diisocyanate, tetramethylxylylene diisocyanate, etc.; aromatic diisocyanates such as TDLMDL naphthylene diisocyanate, etc.)
can be used. Among these, preferred are alicyclic diisocyanates. Particularly preferred among the alicyclic diisocyanates are hydrogenated MDI and IPDI.

Polyether diols (low molecular diols such as ethylene glycol, propylene glycol, 1,3- or 1,4-butanediol,
- Alkylene oxides of methylbentanediol, 1-6-hexanediol, neopentyl glycol, diethylene glycol and cyclohexylene glycol (bisphenols such as bisphenol A) [alkylene oxides having 2 to 4 carbon atoms such as ethylene oxide, propylene oxide, and butylene oxide] or two or more types (random and/or block)] adducts, ring-opening polymers of alkylene oxides (polytetramethylene ether glycol, etc.), polyester diols (dicarboxylic acids such as adipic acid, succinic acid, cepatic acid, azelaic acid) polyester diol, polycaprolactone diol, whose terminal end is a hydroxyl group obtained by the reaction of a low-molecular-weight diol or a polyether diol (such as the above-mentioned low-molecular diol, polyethylene glycol, etc.);
polycarbonate diol, polybutadiene diol,
Examples include hydrogenated polybutadiene diol and mixtures of two or more thereof.

Preferred among the polymeric diols are polyether diol, polyester diol, polycaprolactone diol and polycarbonate diol.

The molecular weight of the polymeric diol is usually 200 to 4,000, preferably 250 to 3,000.

Examples of low-molecular diamines include aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and alicyclic diamines (hydrogenated MBA, 1,4-diaminocyclohexane, 4,4'-diamino-3,3-dimethylcyclohexyl). methane, IPDA), aromatic aliphatic diamines (xylylene diamine, tetramethylxylylene diamine, etc.), aromatic diamines (diphenylmethane diamine, dichlorodiphenylmethane diamine, tolylene diamine, diethyl tolylene diamine, phenylene diamine, etc.), and mixtures of two or more thereof. Among these, alicyclic diamines are preferred. Particularly preferred among the alicyclic diamines are hydrogenated MBA and IPDA.

Low molecular weight diols used if necessary include ethylene glycol, propylene glycol, 1°3-ma or 14-
Butanediol, 3-methylpencunediol, 1.6
-hexanediol, neopentyl glycol, diethylene glycol and cyclohexylene glycol and mixtures of two or more thereof.

Furthermore, monoalcohols (methanol, ethanol, n-butanol, etc.) and monoamines (ethylamine, n-butylamine, di-n-butylamine, monoethanolamine-1-jetanolamine, etc.) can also be used as molecular weight modifiers.

The equivalent ratio of high molecular diol to low molecular diamine and/or low molecular diol is usually 1:0.1 to 1:1O1, preferably 1:0.2 to 1:5. The average active hydrogen (OH, NH2, NH) 5 position of the polymer diol, low-molecular diamine and/or low-molecular diol as a whole is usually 70~
2000, preferably 100-1300.

In producing the polyurethane resin (C), the ratio of organic diisocyanate to polymeric diol, low-molecular diamine and/or active hydrogen compound such as low-molecular diamine is determined by NC.
The equivalent ratio of O to active hydrogen groups (OHlN, HhNH, etc.) is usually 1:0.90 to 1:1.11, preferably 1:0.95 to 1:1.05.

In producing the polyurethane resin (C), the organic diisocyanate and the polymeric diol, the low-molecular diamine, and/or the low-molecular diol if necessary may be reacted all at once, or may be produced by a stepwise reaction method [active hydrogen Produced by reacting a part of the containing compound (for example, a high molecular diol) with an organic diisocyanate to form an NCO-terminated prepolymer, and then reacting the remainder of the active hydrogen-containing compound (for example, a low molecular diamine and/or a low molecular diol). method, etc.).

The polyurethane forming reaction is usually carried out at a temperature of 40 to 140°C, preferably 60 to 120°C (however, when reacting with a diamine, it is usually carried out at a temperature of 80°C or lower, preferably 0 to 70°C).

Examples of solvents include ketone solvents (methyl ethyl ketone, methyl isobutyl ketone, etc.), aromatic solvents (toluene,
xylene, etc.), ester solvents (ethyl acetate, butyl acetate, etc.), alcohol solvents (isopropyl alcohol, t-butyl alcohol, etc.), and the like can be used. The solvent may be added before, during or after the reaction.

The resin concentration of the solvent solution of polyurethane resin (C) is usually 5
-70%, preferably 10-50%. The molecular weight of the polyurethane resin is usually 5000 or more, preferably 1000
It is 0-200000.

In producing the polyurethane dispersion of the present invention, the solid content weight ratio of urethane prepolymer (A), cyclic diamine (B) and polyurethane resin (C) [(A)+(B)
2(C)] is 10:100-300:100.
Preferably it is 20:10G to 200:100.

When reacting the urethane prepolymer (A) and the cyclic diamine (B) in a solvent solution of the polyurethane resin (C), the equivalent ratio of the NCO group of A) to the amine 7 group of (B) is arbitrary, but it is 1 :0.7 to 1:1.2. Preferably 1
:0.8 to 1:1.1. The reaction temperature is usually 80°C or lower, preferably 0 to 70°C.

The polyurethane emulsion used in the present invention is prepared by adding an appropriate amount of a water-in-oil surfactant to the above-mentioned polyurethane dispersion as needed, and adding a saturated amount of water or less to the polyurethane emulsion while stirring. It can be obtained by adding about 30 to 400 parts by weight of water per 100 parts by weight of the solid content of the polymer.

As the surfactant, any conventionally known water-in-oil type surfactants can be used, such as nonionic type surfactants [
Polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene fatty acid ester, polyoxyethylene polyhydric alcohol fatty acid ester (twin type), polyhydric alcohol fatty acid ester (span type), polyoxyethylene propylene polyol (pluronic type) , alkylolamide type, etc.], anionic surfactants (alkyl sulfate salts, alkylphenol sulfonate salts,
sulfosuccinic acid ester salts, etc.), cationic surfactants (alkyltrimethylammonium salts, etc.), amphoteric surfactants (alkyl betaines, alkylimidacillins, etc.), resin activators [polyoxyethylene group-containing urethanes,
urethanes containing carboxylic acid groups (sodium carboxylate, etc.), urethanes containing quaternary ammonium groups (alkyltrimethylammonium salts, etc.)], and mixtures of two or more of these. Preferred is a resin activator (urethane containing a polyoxyethylene group, urethane containing a carboxylic acid group (such as sodium carboxylate), urethane containing a quaternary ammonium group (such as an alkyltrimethylammonium salt)). Particularly preferred is polyoxyethylene group-containing urethane. The amount r of the surfactant added is preferably about 1 to 50 parts by weight per 100 parts by weight of the solid content of the polyurethane polymer.

The polyurethane emulsions used in this invention can contain auxiliary ingredients.

For example, coloring agents such as dyes and pigments for decorative coloring, inorganic fillers such as calcium carbonate and glass fiber, organic modifiers such as AS resin and PVC resin, and various materials for improving light resistance and heat resistance. Stabilizers, water-repellent oil agents, plasticizers, foam stabilizers, antifoaming agents, incyanate crosslinking agents for improving strength, and other additives can be used on the substrate to which the method of the present invention is applied. Examples include knitted fabrics, woven fabrics,
Various materials can be used, such as nonwoven fabric, glass plate, metal plate, paper, plastic, and film.

Methods for applying the polyurethane emulsion to the substrate include known methods such as the footing method and the dipping method.

The amount of coating and/or impregnation can be varied within a wide range depending on the purpose, usually from 1 to 2.000 g/-.

A very short drying step is sufficient to obtain porous sheet materials from polyurethane emulsions by the method of the invention. For example, after coating or impregnating the emulsion on the substrate, the emulsion is heated for 1 to 20 minutes at 50 to 100°C in a circulating air dryer.
1 to 20 minutes at 100 to 150°C as necessary.
Just let it dry for a minute. It is also possible to use a substrate that cannot be heated, and in this case, a porous sheet material can be obtained simply by air drying at room temperature.

The porous sheet material obtained in this way is useful for shoes, bags, furniture, clothing as a substitute for leather, moisture-permeable waterproof fabric or paint, building materials such as floors and walls, and applications such as air filters and filter media. be.

[Example] The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. Parts in Examples and Comparative Examples represent parts by weight.

The raw materials used in the examples and comparative examples are as follows.

(1) High molecular polyol PCL2000; Polycaprolactone diol (molecular weight 2000) PCL800; Polycaprolactone diol (molecular fi800) PBGlooO; Polytetramethylene glycol (molecular weight 1000) (2) Low molecular polyol BD; 1,4-butanediol BPE; 2.5 mol ethylene oxide adduct of bisphenol A (molecular weight 31O) (3) Amine compound HMBA; Hydrogenated MBA IPDA; Isophorone diamine DEA; Jetanolamine (4) Organic polyisocyanate I PD I; Isophorone diisocyanate HMDI
; Hydrogenated MDI MDI; Diphenylmethane diisocyanate (5)
Solvent toluene; Toluene MEK; Methyl ethyl ketone IPA; Isopropyl alcohol production example 1.2
．． 3 Urethane prepolymer (A-1), (A-2), (A-
3); NCO group-containing urethane prepolymer obtained by charging the raw materials shown in Table 1 into a four-bottle flask and reacting at 100°C for 6 hours in a nitrogen atmosphere.
It has the solid content, viscosity, and NCO content shown in .

Production Example 4.5.6 Polyurethane resin solution (C-1), (C-2), (C-
3); Charge the high-molecular diol, low-molecular diol, and diisocyanate shown in Table 2 into a four-bottle flask, react in a nitrogen atmosphere at 100°C for 5 hours to produce an NCO-terminated prepolymer, and then dilute by adding a solvent. After that,
This is a polyurethane resin solution obtained by adding and reacting an amine compound at room temperature, and has the solid content and viscosity shown in Table 2.

Production Example 7 Polyurethane resin solution (C-4); This is a polyurethane resin solution obtained by charging the raw materials shown in Table 2 into a four-loaf flask and reacting them at 70°C for 10 hours in a nitrogen atmosphere. It has solid content and viscosity.

Table 1 Table 2 Example 1 Four-loop flask shown in Tables 1 and 2 (C-1)
After charging 1500 parts, (^-1) 400 parts, MEK 522 parts and IPA 120 parts and stirring and mixing them uniformly, a solution of 42 parts HMBA dissolved in IPA 1211 parts was charged in advance, and the mixture was reacted at 40°C for 3 hours to obtain a solid content of 20%. ,
A white paste-like dispersion (1) was obtained.

100 parts of the obtained dispersion (1), 3.5 parts of surfactant (urethane containing polyethylene group), 38 parts of toluene,
A polyurethane emulsion (1) was prepared by stirring 38 parts of MEK and 20 parts of water using a homogenizer.

Example 2 1500 parts of (C-2) shown in Tables 1 and 2, (A
-2) After preparing and uniformly dissolving and mixing 400 parts of MEK, 543 parts of MEK, and 08 parts of IPAI,
Example 1 by preparing a solution in which 1 part was dissolved in 53 parts of IPAI.
In the same manner as above, a white paste-like dispersion with a solid content of 20% (
2) was obtained.

100 parts of the obtained dispersion (2), surfactant (*'!
114 diethylene group-containing urethane), 30 parts of toluene, MEK3O parts, and 20 parts of water were stirred in the same manner as in Example 1 to prepare a polyurethane emulsion (2).

Example 3 1500 parts of (C-2) shown in Tables 1 and 2, (A
-1) 800 copies, M E K 80 copies and IPA2
After adding 1 part of HM and stirring and mixing it uniformly,
A solution prepared by dissolving 64 parts of B A in 149 parts of IPA was prepared in the same manner as in Example 1 to obtain a white paste-like dispersion (3) with a solid content of 20%.

100 parts of the obtained dispersion (3), 4 parts of a surfactant (urethane containing a polyoxyethylene group), 30 parts of toluene, 30 parts of MEK and 20 parts of water were stirred in the same manner as in Example 1 to form a polyurethane emulsion ( 3) was adjusted.

Example 4 1000 g of (C-3) shown in Tables 1 and 2, (A
-3) 320 parts, M E K 240 parts, toluene 2
After preparing 40 parts and 00 parts of IPAI and stirring and mixing them uniformly, a solution in which part HMBAGO was previously dissolved in 40 parts of IPAI was prepared and the solid content was 20% in the same manner as in Example 1.
A white paste-like dispersion liquid (4) was obtained.

The resulting dispersion (4 NOO parts, surfactant (*'
4 parts of cycin group-containing urethane, 30 parts of toluene,
30 parts of MEK and 20 parts of water were stirred as in Example 1,
A polyurethane emulsion (4) was prepared.

Comparative Example 1 1,000 parts of (C-4), 1,147 parts of MD, 53 parts of BD, and 800 parts of M E K shown in Table 2 were charged and reacted at 70°C for 8 hours in a nitrogen atmosphere to produce a solid content of 259A-white paste. A dispersion liquid (1) was obtained.

100 parts of the obtained comparative dispersion (1), surfactant (N).

4 parts of Rioquinedesine group-containing urethane), Tolue
730 parts of MEK, 30 parts of MEK, and 20 parts of water were stirred in the same manner as in Example 1 to prepare a comparative polyurethane emulsion (1).

Examples 1 to 4, Comparative Example 1 The polyurethane emulsions of Examples 1 to 4 and Comparative Example 1 were coated on a polypropylene plate so that the film thickness after drying was 100μ, and then heated at room temperature for 20 minutes and further at 60°C for 30 minutes. A porous sheet was obtained by drying for several minutes. Table 3 shows the strength and elongation properties of the sheet and the state of the porous membrane.

Table 3 Table-4 Thermal softening point: Measured using a micro-melting point measuring device manufactured by Yanagimoto Shoji Co., Ltd.

Scratch resistance: The degree of recovery of scratches from nail scratches was observed.

X: Significant yellowing was observed.

[Effects of the Invention] The porous sheet material obtained by the present invention has superior heat resistance, scratch resistance, and weather resistance compared to conventional materials. In addition, a porous sheet having fine pores is obtained, exhibiting a good texture and excellent air permeability. Furthermore, the surface of the porous sheet obtained is super matte and has an elegant appearance and feel. The porous sheet material thus obtained is suitable for shoes, bags, furniture, clothing as a substitute for leather, as a moisture-permeable waterproof fabric, or as a coating material for various base materials (cloth, paper, plastic, etc.).

O: The scar is healed and does not remain.

×: A scar remains and the wound does not recover.

Weather resistance: The degree of yellowing was observed after 50 hours of irradiation with an I-tometer.

O: No yellowing observed.

Claims (1)

[Scope of Claims] 1. A method for producing a porous sheet material in which a water-in-oil type polyurethane emulsion consisting of a polyurethane polymer, an organic solvent, and water is coated or impregnated onto a substrate and dried; As a suspension, a urethane prepolymer (A
) and a cyclic diamine (B) having an amino group equivalent of at least 54, and a polyurethane dispersion in which a polyurethaneurea (B) is dispersed in an organic solvent solution of a polyurethane resin (C), and a polyurethane emulsion consisting of water is used. A method for producing a porous sheet material, characterized by: 2. When the polyurethane dispersion is in an organic solvent solution of (C) (
The method according to claim 1, obtained by reacting A) and (B). 3. The method according to claim 1 or 2, wherein the organic polyisocyanate (A) is an alicyclic polyisocyanate. 4. The method according to any one of claims 1 to 3, wherein the cyclic diamine (B) is an alicyclic diamine. 5. Claims 1 to 5, wherein the polyurethane resin (C) is a polyurethane resin made from an alicyclic diisocyanate, a polymeric diol, an alicyclic diamine, and optionally a low-molecular diol.
4. The method described in any one of 4.