JP2928905B2 - Method for producing water-repellent polyurethane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a water-repellent polyurethane.

[0002]

2. Description of the Related Art Conventionally, water-repellent polyurethane has been used as a polyurethane foam for a water-blocking sealing material, a polyurethane elastomer for a sealing material or a roll material which requires a small change in water absorption dimension, and the like. As the polyurethane foam, those obtained by impregnating and adhering a hydrophobic substance such as asphalt to a foam (for example, JP-A-59-213786, JP-A-61-291873)
No. JP-A-63-221186); those obtained by reacting and foaming a hydrophobic skeleton polyol such as polybutadiene polyol, castor oil, and dimer acid-modified polyol with an organic polyisocyanate (for example, JP-A-57-102978).
And polyolefin polyols, hydrogenated polybutadiene polyols, and the like and organic polyisocyanates, and the like (for example, JP-A-63-27583 and JP-A-2-298574). It has been known. Examples of the polyurethane elastomer include those obtained by adding a plasticizer such as dioctyl phthalate, process oil or soybean oil when reacting an organic polyisocyanate with polybutadiene polyol, hydrogenated polybutadiene polyol, castor oil or the like (for example, see Japanese Unexamined Patent Publication No.
No. 7-3835, JP-A-5-247169);
Those obtained by reacting a polyol or an organic polyisocyanate having a fluorine or silicon atom in the molecular structure (JP-A-62-115020, JP-A-63-6025, JP-A-2-258821) are known. ing.

[0003]

However, the above polyurethane foam cures with time and deteriorates in performance; however, the polyurethane foam has carbon-carbon in its molecular structure.
Poor weather resistance due to the presence of carbon double bonds; polyurethane foam has a viscosity of about 100,000 cps
(30 ° C.), which is difficult to handle; polyurethane elastomers bleed out of the plasticizer over time after curing; polyurethane elastomers have a high material cost and lack economical efficiency, which limits their use. there were.

[0004]

Means for Solving the Problems The present inventors have solved these problems, have no performance deterioration over time, have a low viscosity polyol, and are easy to handle.
As a result of intensive studies on a method for producing a polyurethane having excellent water repellency, the present invention has been reached. That is, the present invention relates to a method for producing a water-repellent polyurethane using a water-repellent polyol (A) and an organic polyisocyanate (B) as essential components, wherein (A) is a polyether polyol (a1), HLB of ~ 3 and 400
An ethylenically unsaturated monomer (co) polymer (a2) having a weight average molecular weight of ~ 5000, wherein the weight ratio of (a1) and (a2) is (95-20): (5-80), A process for producing a water-repellent polyurethane, which comprises using a water-repellent polyol in which (a1) and (a2) are substantially compatible.

The ethylenically unsaturated monomer (co) polymer (a2) used in the present invention is obtained by (co) polymerizing at least one of the following ethylenically unsaturated monomers. Examples of the ethylenically unsaturated monomer include unsaturated carboxylic acid esters [alkyl (meth) acrylate having 4 to 30 carbon atoms, fumaric acid ester, maleic acid ester, etc.], aromatic vinyl (styrene, alkylstyrene, etc.), Vinyl halide (vinyl chloride, vinylidene chloride, etc.), organic acid vinyl ester (vinyl acetate, vinyl propionate, etc.), unsaturated nitrile [(meth) acrylonitrile, etc.), unsaturated amide [(meth) acrylamide, etc.), unsaturated carboxylic acid Acid [(meth) acrylic acid, crotonic acid, itaconic acid, etc.],
Unsaturated carboxylic anhydrides (such as maleic anhydride), vinyl ethers (such as vinyl methyl ether), and hydroxyl group-containing unsaturated monomers [such as hydroxyalkyl (meth) acrylate, allyl alcohol, and monoallyl ether of polyhydric alcohols]. . Among these, preferred are alkyl (meth) acrylates having 4 to 30 carbon atoms,
Styrene, (meth) acrylonitrile, allyl alcohol and hydroxyethyl (meth) acrylate.

The HLB (HYDROPHILE) of (a2)
-LIPOPHILE BALANCE) is usually 0 to
3, preferably 0 to 2. When HLB exceeds 3,
The resulting polyurethane cannot have sufficient water repellency. The HLB used here is the method of Oda et al. [Source: Oda, Teramura "Synthesis of Surfactant and Its Application" 501
Page, published by Maki Shoten (1957)]. HLB is used as a numerical value representing hydrophilicity, and is indicated by a numerical value in the range of 0 to 40, and the larger the numerical value, the higher the hydrophilicity.

The weight average molecular weight of (a2) is usually from 400 to 5,000, preferably from 400 to 2,000. If the weight average molecular weight is less than 400, a bleed-out phenomenon from the polyurethane tends to occur, and if it exceeds 5000, the compatibility with the polyether polyol (a1) is reduced.

The polyether polyol (a1) used in the present invention is an alkylene oxide adduct of the following active hydrogen atom-containing compound. Examples of the compound containing an active hydrogen atom include polyhydric alcohols (ethylene glycol, propylene glycol, 1,4-butanediol, glycerin, trimethylolpropane, pentaerythritol, sorbitol, sucrose, etc.); ammonia; , Monoamines (butylamine, etc.), aliphatic polyamines (ethylenediamine, triethylenediamine, diethylenetriamine, etc.), alicyclic polyamines (piperazine, N-aminoethylpiperazine, etc.), aromatic polyamines (phenylenediamine, tolylenediamine, xylylenediamine) , Diphenylmethanediamine, polyphenylmethanepolyamine, etc.) and alkanolamines (monoethanolamine, diethanolamine, triethanolamine, etc.)]; polyhydric phenols [ Polyphenols (such as pyrogallol and hydroquinone) and bisphenols (such as bisphenol A); polycarboxylic acids [aliphatic polycarboxylic acids (such as succinic acid and adipic acid), and aromatic polycarboxylic acids (phthalic acid, terephthalic acid, and tricarboxylic acid). And a mixture of two or more of these. Examples of the alkylene oxide include ethylene oxide (EO), propylene oxide (PO), 1,2-, 1,4- or 2,3-butylene oxide, styrene oxide, an α-olefin oxide having 5 to 30 carbon atoms, and these. Two or more of them may be used in combination. The addition method of the alkylene oxide may be a conventional method, and when used in combination, the addition form may be either block or random.

The polyether polyol (a1) is preferably a polyhydric alcohol containing PO alone or PO.
And EO in combination, particularly preferably ethylene glycol, propylene glycol,
A compound obtained by adding PO alone or a combination of PO and EO to at least one of glycerin, trimethylolpropane, and pentaerythritol.
The average number of functional groups of (a1) is usually 2 to 5, preferably 2 to
4. The average hydroxyl value is usually from 10 to 1,000, preferably from 15 to 400. When the average functional group number is less than 2 or the average hydroxyl value is less than 10, when used for polyurethane foam, the compression set and wet heat compression set become large, and when used for polyurethane elastomer, the reactivity is low and the curability is low. Will be insufficient. On the other hand, when the average number of functional groups exceeds 5 or the average hydroxyl value exceeds 1000,
When used for polyurethane foam, the polymer forming the foam is rigid and the polyurethane foam becomes brittle,
When used for polyurethane elastomer, elongation is small.

The weight ratio of (a1) to (a2) in the water-repellent polyol (A) used in the present invention is usually (95-20) :( 5-80), preferably (95-5).
0): (5 to 50). When the ratio of (a2) is less than 5, the obtained polyurethane cannot have sufficient water repellency, and when it exceeds 80, the obtained polyurethane has an adverse effect on various properties such as elongation and compression set.

As a method of substantially compatibilizing (a1) and (a2) constituting (A), (a1) includes (a)
A method of heating and dissolving 2) and a method of (co) polymerizing an ethylenically unsaturated monomer in (a1) may be mentioned, but the method is preferably. The above method is a method of synthesizing a conventionally known polymer polyol (for example,
JP-B-39-24737, JP-B-47-47999
No., JP-A-50-15894 and U.S. Pat. No. 3,383,351).

In (A) used in the present invention, (a1)
It is sufficient that (a2) is substantially compatible with (a2), and complete dissolution is preferable. However, a part of (a2) (usually 40% by weight or less,
(Preferably 20% by weight or less) may be dispersed in (a1). If the insoluble portion of (a2) in (a1) exceeds 40% by weight, sufficient water repellency cannot be obtained when used for polyurethane foam, and sufficient water repellency can be obtained when used for polyurethane elastomer. In addition, the surface smoothness of the polyurethane elastomer deteriorates, which is not suitable as a sealing material or a roll material.

In the present invention, if necessary, other known polyols may be used together with the water-repellent polyol (A) as the polyol component. Other polyols that can be used in combination include known polyols commonly used for polyurethanes, and specific examples thereof include high molecular weight polyols having two or more hydroxyl groups at molecular terminals (for example, polyether polyols, polyester polyols, polyester polyamides). Polyols, polycarbonate polyols, polycaprolactone polyester polyols, polybutadiene polyols, hydrogenated polybutadiene polyols, polypentadiene polyols, castor oil-based polyols, etc.);
Low molecular weight polyols (eg, trimethylolpropane, glycerin, sorbitol, mannitol, dulcitol, etc.). Of these, preferred are polyether polyols, polybutadiene polyols and hydrogenated polybutadiene polyols. These other polyols are used in combination such that the average number of functional groups of all polyol components is usually 2 to 5, preferably 2 to 4.

As the organic polyisocyanate (B),
Known ones usually used for polyurethane, for example, aromatic polyisocyanates having 6 to 20 carbon atoms (excluding the number of carbon atoms in the NCO group) [2,4- or 2,6-tolylene diisocyanate (TDI), crude TDI , 2,4'- or 4,4'-diphenylmethane diisocyanate (MD
I), crude MDI, polyaryl polyisocyanate (PAPI), etc.]; aliphatic isocyanates having 2 to 18 carbon atoms (hexamethylene diisocyanate, lysine diisocyanate, etc.); alicyclic polyisocyanates having 4 to 18 carbon atoms (isophorone diisocyanate, Dicyclohexyl diisocyanate, etc.); modified products of these polyisocyanates (urethane group, carbodiimide group, allophanate group, urea group, uretdione group, buret group,
Uretonimine groups, isocyanurate groups, oxazolidone group-containing modified products, etc.); and mixtures of two or more of these.

In the present invention, if necessary, known catalysts usually used for producing polyurethane can be used. Examples of the catalyst include metal salts of carboxylic acids [sodium acetate, potassium octylate, lead octylate, zinc octylate, cobalt naphthenate, stannas octoate, etc.]; alkoxides or phenoxides of alkali metals or alkaline earth metals [sodium Methoxide,
Tertiary amines [triethylamine, triethylenediamine, N-methylmorpholine, dimethylaminomethylphenol, etc.]; quaternary ammonium salts [tetraethylammonium hydroxide, etc.]; imidazoles [imidazole, 2-ethyl-
4-methylimidazole and the like]; organometallic compounds containing metals such as tin and antimony [tetraphenyltin, tributylantimony oxide and the like]. Of these, preferred are tertiary amines, metal salts of carboxylic acids containing tin or lead, organometallic compounds, and combinations of two or more of these.

In the present invention, a foam stabilizer can be used if necessary. Specific examples include SZ-1306, L-5309, and L-52 manufactured by Nippon Unicar Co., Ltd.
0, L-540, L-5420, L-580 and SZ
-1127; Dow Corning Toray Silicone Co., Ltd.
SH-190, SH-193, SF-8427, S
RX-294A and SRX-274C dimethylsiloxane-based foam stabilizers.

In the present invention, a chain extender and / or a crosslinking agent can be used if necessary. As the chain extender and / or the cross-linking agent, those which can be generally used for polyurethane are used. Specific examples include ethylene glycol, diethanolamine, triethanolamine,
PO and / or EO such as glycerin, trimethylolpropane, D-sorbitol, or diethanolamine, triethanolamine, diethylenetriamine, etc.
And adducts.

In the present invention, a foaming agent can be used if necessary. As the blowing agent, water alone is mainly used, but if necessary, a low boiling point blowing agent such as methylene chloride can be used in combination.

The polyurethane can be produced by a conventionally known method, and any one of a one-shot method, a prepolymer method and a quasi-prepolymer method can be applied. The production method may be a conventionally known method, and may be a slab method, a hot cure method, a cold cure method, a RIM method, molding by an open mold, integral molding with a composite material, an on-site construction method, a spray method, a casting method, pouring, and coating. ,
Any of impregnation and the like can be applied. Specifically,
No. 24737, JP-B-47-15108, JP-A-Showa 4
6-5750, JP-A-55-133417, etc .;
JP-A-50-23497, JP-A-53-1679
No. 6, JP-A-53-42294, etc. can be used, and the catalysts, surfactants and other auxiliaries, equivalent ratios, addition amounts, etc. described in these can be used. Things can be used.

[0020]

The present invention will be described in more detail with reference to the following examples, which, however, are not intended to limit the scope of the present invention. In addition, the numerical value of the foaming prescription column in an Example and a comparative example shows a weight part. [Explanation of Symbols of Raw Materials Used] Polyether polyol (a1) a1-1: PO adduct of glycerin, hydroxyl value = 56 a1-2: PO adduct of propylene glycol, hydroxyl value = 56 ethylenically unsaturated monomer (co ) Polymer (a2) a2-1: "Hymer SB-7" manufactured by Sanyo Chemical Industries, Ltd.
5 "(styrene polymer, weight average molecular weight 2000) a2-2:" Hymer ST-12 "manufactured by Sanyo Chemical Industries, Ltd.
0 "(styrene polymer, weight average molecular weight 10,000) a2-8:" PP401-B "(styrene oligomer, number average molecular weight 306) manufactured by Kawasaki Steel Corporation Organic polyisocyanate (B) B-1: Nippon Polyurethane Industry ( "Coronate T-80" (TDI-80, NCO% = 48.3) B-2: "Millionate MT" (MDI, NCO% = 33.6) manufactured by Nippon Polyurethane Industry Co., Ltd. Other auxiliaries Catalyst-1: "Minicoil L-10" manufactured by Active Materials Chemical Co., Ltd.
20 "(33% dipropylene glycol solution of triethylenediamine) Catalyst-2:" Neostan U-28 "manufactured by Nitto Kasei Corporation
(Stannas dioctoate) Catalyst-3: Lead octylate Foam stabilizer: Nippon Unicar Co., Ltd. "L-520" (dimethylsiloxane foam stabilizer) Crosslinker: Glycerin Chain extender: 1,4-butylene glycol

Production Example 1 Kolben was added to polyether polyol (a1-1) 300
After the temperature was increased to 140 ° C. while stirring, 30 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) was added to 500 parts by weight of (a1-1) and 200 parts by weight of styrene. The solution was added dropwise over 4 hours. After dropping, the mixture was aged at the same temperature for 1 hour, and then the unreacted monomer was stripped to remove the water-repellent polyol (A-
1) [Viscosity 1500 cps (25 ° C.), weight average molecular weight of styrene polymer 1200, HLB = 0.9] was obtained.

Production Example 2 Kolben was added to polyether polyol (a1-1) 150
After the temperature was increased to 140 ° C. while stirring, 60 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) was added to 250 parts by weight of (a1-1) and 400 parts by weight of styrene. The solution was added dropwise over 6 hours. After dropping, the mixture was aged at the same temperature for 1 hour, and then the unreacted monomer was stripped to remove the water-repellent polyol (A-
2) [Viscosity 6200 cps (25 ° C.), weight average molecular weight of styrene polymer 2000, HLB = 0.9] was obtained.

Production Example 3 Polyether polyol (a1-1) 300 was added to Kolben.
After the temperature was increased to 140 ° C. while stirring, 500 parts by weight of (a1-1), 146 parts by weight of styrene, and 50 parts of linear alkyl acrylate having 14 to 16 carbon atoms were used.
A solution of 30 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) in 4 parts by weight of 2-hydroxyethyl acrylate and 4 parts by weight of 2-hydroxyethyl acrylate was added dropwise over 4 hours. After dropping, the mixture was aged at the same temperature for 1 hour, and then the unreacted monomer was stripped to remove the water-repellent polyol (A-
3) [Viscosity 1200 cps (25 ° C.), weight average molecular weight of ethylenically unsaturated monomer copolymer 1000, HLB
= 1.4].

Production Example 4 1000 parts by weight of dehydrated toluene, 10 parts by weight of acetic anhydride, and 6 parts by weight of boron trifluoride diethyl ether complex were charged in a Kolben, and the mixture was heated to reflux temperature with stirring.
A mixture of 700 parts by weight of styrene and 300 parts by weight of a linear alkyl acrylate having 14 to 16 carbon atoms was added dropwise over 4 hours. After dropping, the mixture was aged for 1 hour while continuing to reflux, and then the solvent was distilled off to obtain an ethylenically unsaturated monomer copolymer (a2-3) [weight average molecular weight of copolymer: 1000, H
LB = 1.1].

Production Example 5 1000 parts by weight of dehydrated toluene, 10 parts by weight of acetic anhydride, and 6 parts by weight of boron trifluoride diethyl ether complex were charged in a Kolben, and the mixture was heated to the reflux temperature with stirring.
A mixture of 950 parts by weight of styrene and 50 parts by weight of acrylonitrile was added dropwise over 4 hours. After dropping, the mixture was aged for 1 hour while continuing to reflux, and then the solvent was distilled off to obtain an ethylenically unsaturated monomer copolymer (a2-4) [weight average molecular weight of copolymer: 1800, HLB = 1.7].

Production Example 6 Kolben was charged with 1000 parts by weight of dehydrated toluene, 10 parts by weight of acetic anhydride, and 6 parts by weight of a boron trifluoride diethyl ether complex.
A mixture of 730 parts by weight of styrene, 250 parts by weight of linear alkyl acrylate having 14 to 16 carbon atoms and 20 parts by weight of 2-hydroxyethyl acrylate was added dropwise over 4 hours. After dropping and aging for 1 hour while continuing to reflux,
The solvent is distilled off to obtain an ethylenically unsaturated monomer copolymer (a2
-5) [Weight average molecular weight of copolymer: 1200, HLB =
1.4] was obtained.

Production Example 7 1000 parts by weight of dehydrated toluene, 10 parts by weight of acetic anhydride and 6 parts by weight of boron trifluoride diethyl ether complex were charged into a kolben, and the mixture was heated to the reflux temperature with stirring.
A mixture of 996 parts by weight of a linear alkyl acrylate having 14 to 16 carbon atoms and 4 parts by weight of allyl alcohol was added dropwise over 4 hours. After dropping, the mixture was aged for 1 hour while continuing to reflux, and then the solvent was distilled off to obtain an ethylenically unsaturated monomer copolymer (a2-6) [weight average molecular weight of copolymer: 100
0, HLB = 2.0].

Production Example 8 1000 parts by weight of dehydrated toluene, 10 parts by weight of acetic anhydride, and 6 parts by weight of boron trifluoride diethyl ether complex were charged in a kolben, and the mixture was heated to the reflux temperature with stirring.
A mixture of 500 parts by weight of styrene and 500 parts by weight of acrylonitrile was added dropwise over 4 hours. After dropping, the mixture was aged for 1 hour while continuing to reflux, and then the solvent was distilled off to obtain an ethylenically unsaturated monomer copolymer (a2-7) [weight average molecular weight of copolymer: 2,000, HLB = 4.8].

Examples 1 to 9 and Comparative Examples 1 to 5 Slab foaming was carried out using a low-pressure foaming machine in accordance with the foaming formulations shown in Tables 1, 2 and 3. After standing overnight, the polyurethane foam was cut and its physical properties were measured. The results are shown in Tables 1, 2 and 3. [Physical property measurement method] Density: The apparent density of the polyurethane foam is shown (unit: kg / m ³ ). -Water stoppage: A U-shaped urethane foam sample having a width of 10 mm and a thickness of 15 mm is set on one acrylic plate, and further, a spacer for holding the U-shaped urethane foam sample at a predetermined compression ratio is applied, and the other is used. After stacking the acrylic plates, the two acrylic plates are tightened using bolts and nuts to compress and fix the U-shaped urethane foam sample to a predetermined compression ratio. Next, water is poured into the inside of the U-shaped urethane foam sample from the gap between the two acrylic plates so as to have a predetermined water level, and left. The test was started immediately after the injection, and the time until water leaked out of the U-shaped urethane foam sample was measured. Table 1, Table 2 and Table 3
Are measured at a compression ratio of 70% and a water height of 50 mm (unit is time).

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

Example 10 and Comparative Example 6 Slab foaming was performed using a low-pressure foaming machine according to the foaming recipe shown in Table 4. After standing overnight, the U-shaped urethane foam sample obtained by cutting the polyurethane foam was used for 100
The change in water stoppage (temporal change in water repellency) after heating at a constant temperature for 1 hour was measured. Table 4 shows the results.

[0034]

[Table 4]

Production Example 9 In a Kolben, polyether polyol (a1-1) 4
00 parts by weight, polyether polyol (a1-2) 40
A solution obtained by dissolving 200 parts by weight of an ethylenically unsaturated monomer polymer (a2-1) in 0 parts by weight of a mixture was charged with 257 parts by weight of an organic polyisocyanate (B-2), and heated at 80 ° C. under a nitrogen stream. The mixture was stirred and reacted for 6 hours to obtain [Prepolymer 1] having an NCO% of 4.0%.

Production Example 10 Polyether polyol (a1-1) 3
00 parts by weight, polyether polyol (a1-2) 30
A mixture prepared by dissolving 400 parts by weight of an ethylenically unsaturated monomer polymer (a2-1) in 0 parts by weight of a mixture was charged with 193 parts by weight of an organic polyisocyanate (B-2), and heated at 80 ° C. under a nitrogen stream. The mixture was stirred and reacted for 6 hours to obtain [Prepolymer 2] having an NCO% of 3.1%.

Production Example 11 Polyether polyol (a1-1) 4
00 parts by weight, polyether polyol (a1-2) 40
To a mixture obtained by dissolving 200 parts by weight of an ethylenically unsaturated monomer copolymer (a2-5) in 0 parts by weight of a mixture, 257 parts by weight of an organic polyisocyanate (B-2) was charged, and heated to 80 ° C. under a nitrogen stream. And react for 6 hours with stirring.
Yielded 3.8% of [Prepolymer 3].

Production Example 12 Polyether polyol (a1-1) 5 was added to Kolben.
00 parts by weight, polyether polyol (a1-2) 50
0 parts by weight and 322 parts by weight of the organic polyisocyanate (B-2) were charged and stirred and reacted at 80 ° C. for 6 hours under a nitrogen stream to obtain [Prepolymer 4] having an NCO% of 4.7%.

Production Example 13 In a Kolben, polyether polyol (a1-1) 5
0 parts by weight and a mixture of 50 parts by weight of the polyether polyol (a1-2) are mixed with an ethylenically unsaturated monomer polymer (a
2-1) A solution prepared by dissolving 900 parts by weight, 64 parts by weight of the organic polyisocyanate (B-2) is charged, and the mixture is stirred and reacted at 80 ° C. for 6 hours under a nitrogen stream to give an NCO% of 0.9.
% [Prepolymer 5] was obtained.

Examples 11 to 13 and Comparative Examples 7 to 9 After kneading according to the formulation shown in Table 5, 100
Cured at ℃ for 1 hour. After standing overnight, the physical properties of the polyurethane elastomer were measured. Table 5 shows the results. [Physical property measurement method] A hardness: Measured with a Shore A hardness meter. JIS K-63
01 compliant. -Elongation: Based on JIS K-6301 (unit is%).・ Water absorption: 25 ° C of polyurethane elastomer molded product
Calculated from the change in weight before and after immersion in water for 24 hours (unit:%).

[0041]

[Table 5]

[0042]

According to the method of the present invention, it is possible to produce a polyurethane having excellent water repellency without performance degradation over time. Further, the water-repellent polyol used has low viscosity and is easy to handle. Due to the above effects, the water-repellent polyurethane obtained by the method of the present invention is particularly useful for industrial applications such as a polyurethane foam for a waterproof sealing material, a roll material and a polyurethane elastomer for a sealing material requiring a small change in water absorption dimension. It is.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-16764 (JP, A) JP-A-60-76589 (JP, A) JP-A-58-57414 (JP, A) JP-A-58-574 11518 (JP, A) JP-A-51-111295 (JP, A) JP-A-62-104829 (JP, A) JP-A-51-111294 (JP, A) JP-A-61-115983 (JP, A) JP-A-54-85299 (JP, A) JP-A-61-200116 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08G 18/40-18/69

Claims (3)

(57) [Claims] 1. A method for producing a water-repellent polyurethane using a water-repellent polyol (A) and an organic polyisocyanate (B) as essential components, wherein (A) is a polyether polyol (a1), And an ethylenically unsaturated monomer (co) polymer (a2) having an HLB of from 3 to 3 and a weight average molecular weight of from 400 to 5000,
The weight ratio of (a1) and (a2) is (95-20): (5-
80), which comprises using a water-repellent polyol which is substantially compatible with (a1) and (a2). 2. The process according to claim 1, wherein (A) is a (co) polymerization of an ethylenically unsaturated monomer in (a1). 3. An ethylenically unsaturated monomer constituting (a2) is selected from the group consisting of alkyl (meth) acrylates having 4 to 30 carbon atoms, styrene, (meth) acrylonitrile, allyl alcohol and hydroxyethyl (meth) acrylate. 3. A method according to claim 1 or 2, wherein the HLB is at least one selected to give from 0 to 3 (co) polymers.