JPH08253545A - Production of crosslinkable urethane resin and crosslinkable urethane resin composition - Google Patents

Abstract

PURPOSE: To obtain a urethane resin not emitting any harmful isocyanate compound, and therefore not deleterious to the working environment and being capable of exhibiting excellent wet-process crosslinkability by reacting a starting material component essentialy consisting of a compound (A) having two functional groups having active hydrogen atoms in the molecule and having a hydrolyzable silyl group, a long-chain polyhydroxy compound (B) and an organic polyisocyanate (C). CONSTITUTION: It is preferable that component A is N-β-(aminoethyl)-γ- aminopropyltrimethoxysilane, component B is a polyester polyol or polyether polyol having a molecular weight of 1000-3000, and component C is phenylene diisocyanate. The mixing ratio among these components is such that the component A is used in an amount of 0.1-30wt.% based on the total weight of the starting material components, and the component C is used in an amount of 0.9-1.1 equivalents per equivalent of the total active hydrogen atoms of components other than component C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel method for producing a polyurethane resin capable of forming a strong cured product by a crosslinking reaction due to moisture and a crosslinkable urethane resin composition containing the same, which can be used for artificial leather and synthetic leather. , Adhesives, sealing agents, coating agents, films, sheets and the like.

[0002]

Polyurethane resins, which are general-purpose resins, are used in a very wide range of applications such as artificial leather, synthetic leather, adhesives, sealing agents, coating agents, films and sheets. In these applications, attempts have been made to improve the strength, adhesive strength, durability, and solvent resistance by causing a crosslinking reaction during use, and various crosslinking methods have been proposed.

Specifically, for example, a urethane resin obtained by a conventional method is used as a urethane prepolymer, and a polyisocyanate compound is used as a crosslinking agent together with the urethane prepolymer to cause a crosslinking reaction to obtain a cured product. When the urethane prepolymer is produced, the raw polyisocyanate compound is used in a large excess to carry out the reaction, and a prepolymer having isocyanate groups at both ends of the polyurethane resin is prepared.
A method of crosslinking with water in the air can be mentioned.

[0004]

However, the method of using the above polyisocyanate compound as a crosslinking agent or the method of leaving an isocyanate group in the urethane prepolymer is not limited to the isocyanate compound which is a poisonous substance in the composition. However, there is a problem in that the compound is volatilized during use, and safety for workers cannot be ensured.

The problem to be solved by the present invention is to prevent the harmful isocyanate compound from volatilizing during use.
Another object of the present invention is to provide a urethane resin that exhibits excellent wet crosslinkability, and a crosslinkable urethane resin composition that is excellent in worker safety and has excellent curability and a strong crosslinked cured product.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a urethane resin having a hydrolyzable silyl group introduced into its molecular side chain is formed into a wet film. It was discovered that the formation of a strong network structure by the hydrolysis of the hydrolyzable silyl group and the crosslinking by the condensation reaction significantly improves the strength, adhesive strength, durability, solvent resistance, heat resistance and toluene resistance of the urethane resin. The present invention has been completed.

That is, the present invention provides a compound (A) having two functional groups having active hydrogen atoms per molecule and a hydrolyzable silyl group, and a long-chain polyhydroxy compound (B). A method for producing a crosslinkable urethane resin, which comprises reacting an organic polyisocyanate (C) as an essential raw material component, and a urethane resin having a hydrolyzable silyl group in a side chain and an organic solvent. The present invention relates to a crosslinkable urethane resin composition, which comprises and as essential components.

The compound (A) used in the present invention is not particularly limited as long as it has two functional groups having active hydrogen atoms per molecule and a hydrolyzable silyl group. Although not limited to these, examples of the functional group having an active hydrogen atom include an amino group and a hydroxyl group. Of these, an amino group is preferable because it is highly reactive with an isocyanate group. On the other hand, the hydrolyzable silyl group includes a silyl group that is easily hydrolyzed, such as a halosilyl group, an alkoxysilyl group, an acyloxysilyl group, a phenoxysilyl group, an iminooxysilyl group or an alkenyloxysilyl group. More specifically, those represented by the following general formula (1) can be mentioned.

[0009]

Embedded image (However, R 1 in the formula is a hydrogen atom or an alkyl group,
A monovalent organic group consisting of an aryl group or an aralkyl group,
R2 represents a halogen atom or an alkoxyl group, an acyloxy group, a phenoxy group, an iminooxy group or an alkenyloxy group, and a represents 0 or an integer of 1 or 2. )

Among such hydrolyzable silyl groups, especially trimethoxysilyl group, triethoxysilyl group,
A (methyl) dimethoxysilyl group and a (methyl) diethoxysilyl group are preferable because crosslinking easily proceeds.

The molecular structure of the compound (A) is not particularly limited as long as it is a compound having the above-mentioned functional group, but more specifically, N-β (aminoethyl) γ.
-Aminopropyltrimethoxysilane, N-β (hydroxylethyl) γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropyltriethoxysilane, N-β (hydroxylethyl) γ-aminopropyltriethoxy Silane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-
Examples include β (aminoethyl) γ-aminopropylmethyldiethoxysilane, N-β (hydroxylethyl) γ-aminopropylmethyldimethoxysilane, and N-β (hydroxylethyl) γ-aminopropylmethyldiethoxysilane.

The above-mentioned compound (A) contains 1
The functional group having two active hydrogen atoms per molecule reacts with the isocyanate group in the polyisocyanate compound (C) described later to form a urethane bond or a urea bond, and the urethane resin finally obtained A structure in which a hydrolyzable silyl group is suspended on a polymer side chain is formed.

Next, the long-chain polyhydroxy compound (B) used in the present invention is not particularly limited,
Examples thereof include polyester diols or polyether diols, or mixtures or copolymers thereof.

Examples of polyester diols include ethylene glycol, 1,2-propylene glycol,
1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentane Diol, 1,8
-Octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol,
One or more diols such as cyclohexane-1,4-dimethanol and succinic acid, maleic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid Examples thereof include an acid and a condensate with one or more dicarboxylic acids such as hexahydroisophthalic acid. In addition, ring-opening polymerization products such as γ-butyrolactone and ε-caprolactone which use the above-mentioned glycol component as an initiator can also be used.

On the other hand, as the polyether diol,
Ethylene glycol, 1,2-propylene glycol,
1,3-propylene glycol, 1,3-butylene glycol, 1,4-butylene glycol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 3-methyl-1,5-pentane Diol, 1,8
-Octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol,
A glycol component such as cyclohexane-1,4-dimethanol, or ethylene oxide, propylene oxide, butylene oxide, or styrene oxide, which uses the polyester polyol as an initiator, or 2
Examples include ring-opening polymers of at least one kind and ring-opening polymers of tetrahydrofuran. Further, ring-opening addition polymers such as γ-butyrolactone and ε-caprolactone to these polyether diols can also be used.

Furthermore, known polyhydric alcohols such as diethylene glycol, triethylene glycol, 1,
5-pentanediol, 1,6-hexanediol, dimethyl-1,5-pentanediol, dimethyl-1,6
-Hexanediol, 1,8-octanediol, cyclohexane-1,4-diol, cyclohexane-1,
Also included are poly (alkylene carbonate) diols obtained by condensation of 4-dimethanol and the like with diaryl carbonate, dialkyl carbonate, or alkylene carbonate.

Among these long-chain polyhydroxy compounds (B), polyester-based diols are preferable from the viewpoint that the adhesive strength is extremely good, especially for adhesive applications.

The long-chain polyhydroxy compound (B) is not particularly specified in its molecular weight, but it usually has a molecular weight of 500 to 5,000, and particularly 1,
It is preferably from 000 to 3,000 from the viewpoint of good adhesion.

The organic polyisocyanate (C) of the present invention is not particularly limited, but for example, aromatic diisocyanates such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate and naphthalene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, Aliphatic or alicyclic diisocyanates such as cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethylxylylene isocyanate are listed. Among these, aromatic diisocyanates are particularly preferable from the viewpoint of adhesive strength, and aliphatic or alicyclic diisocyanates are preferable from the viewpoint of durability and light resistance.

In the present invention, the desired urethane resin can be obtained by reacting each of the above-mentioned components (A) to (C), and a chain extender (D) is further added to each of the above-mentioned raw material components. It is possible to react in combination.

As the chain extender (D), for example, ethylene glycol, 1,2-propylene glycol, 1,3-
Propylene glycol, 1,3-butylene glycol,
1,4-butylene glycol, 2,2-dimethyl-1,
3-propanediol, 1,6-hexanediol, 3
-Methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol and other diols , Ethylenediamine, 1,3-propylenediamine, 1,2-
Propylenediamine, hexamethylenediamine, hydrazine, piperazine, N, N'-diaminopiperazine, 2
1-diamines such as methylpiperazine, 4,4'-diaminodicyclohexylmethane and isophoronediamine
Seed or a mixture of two or more species.

The ratio of the above components to be used in the reaction is not particularly limited, but it has two functional groups having active hydrogen atoms per molecule and has a hydrolyzable silyl group. It is preferable that the compound (A) is used in a proportion of 0.1 to 30% by weight with respect to the total weight of the raw material components for the reaction so that the degree of crosslinking is in an appropriate range.

Further, in the present invention, the amount of the organic polyisocyanate (C) used is usually 0.9 to 1 when the total active hydrogen of (A), (B) and (D) is 1 equivalent.
When it is used in a ratio of 1.1 equivalents, the effect of improving safety due to volatilization of the isocyanate compound becomes remarkable.

The components (A), (C) and (B) (and optionally the component (D)) can be reacted by a conventionally known method. For example, it is suitable to carry out at a reaction temperature of 30 to 250 ° C. in a solventless or organic solvent.
In the case of solution reaction, organic solvents such as ethyl acetate, butyl acetate, methyl ethyl ketone, toluene, tetrahydrofuran, isopropanol, cyclohexanone, dimethylformamide (DMF), cellosolve, cellosolve acetate are used at the beginning of the reaction, during the reaction, at the end of the reaction and at the end of the reaction. It can be added at any of these stages.

In producing the polyurethane resin, if necessary, a monoalcohol, a trifunctional or higher functional alcohol,
Organic monoamines, trifunctional or higher functional amines, organic monoisocyanates, and trifunctional or higher functional polyisocyanates may be used.

In this reaction, if necessary, a catalyst and a stabilizer can be used. These catalysts and stabilizers can be added at any stage.

As the catalyst, for example, triethylamine,
Examples thereof include nitrogen-containing compounds such as triethylenediamine and morpholine, metal salts such as potassium acetate, zinc stearate and tin octylate, and organometallic compounds such as dibutyltin dilaurate.

As the stabilizer, a stabilizer against ultraviolet rays such as substituted benzotriazoles and a stabilizer against thermal oxidation such as phenol derivatives can be added.

The polyurethane resin thus obtained is not particularly limited and usually has a number average molecular weight of 5,000 to 500,000. From 5,000 to 1
It is preferably 10,000, and in the use of artificial leather and synthetic leather, it is preferably 10,000 to 100,000 from the viewpoint of impregnation into a nonwoven fabric and toluene resistance.

The content of the hydrolyzable silyl group for carrying out the crosslinking reaction of the urethane resin is not particularly limited, but the content of the hydrolyzable silyl group in the urethane resin is An average of 0.8 to 50 is preferable because the degree of crosslinking is in an appropriate range.

The crosslinkable urethane resin composition of the present invention contains the above-mentioned crosslinkable urethane resin and an organic solvent as essential components, and the organic solvent which can be used is not particularly specified. In order to facilitate wet cross-linking, an organic solvent that is soluble in water is usually preferable.

As the organic solvent which is soluble in water,
Non-limiting examples include dimethylformamide, diethylformamide, dimethylacetamide, formylmorpholine, hexamethylphosphoramide, dimethylsulfoxide and the like. All of these organic solvents may be used at the beginning of the urethanization reaction, or a part thereof may be divided and used during the reaction, or may be further added after the production of the crosslinkable urethane resin.

The concentration of the polyurethane resin solution is not limited, but usually 15 to 40% is applied in consideration of economy and workability. Further, the wet film forming conditions are not limited, but usually a polymer solution coating layer at 0 to 100 ° C., preferably room temperature to 70 ° C., using water or a mixed solution of water and a solvent of polyurethane resin as a coagulating liquid. Is immersed in a coagulating liquid for a predetermined time to form a film. The higher the concentration of the solvent in the coagulation bath, the more advantageous the recovery of the polyurethane resin solvent after the coagulation treatment, and the polyurethane resin solution obtained by the present invention has good film formation even at a high solvent concentration (more than 20%). Maintain sex.

The polyurethane resin composition of the present invention may contain stabilizers such as antioxidants, lubricants, non-solvents, pigments, fillers, antistatic agents and other additives. The crosslinkable urethane resin composition of the present invention does not necessarily require the addition of a curing catalyst, and therefore, even if no such curing catalyst is added, it has good curability, but When it is necessary to improve the curability, for the hydrolysis of the hydrolyzable silyl group,
Then, it is preferable to use a catalyst which is a condensation catalyst.

As such catalysts, if only representative ones are exemplified, various basic compounds such as lithium hydroxide, sodium hydroxide, potassium hydroxide or sodium methylate; tetraisopropyl titanate , Tetra-n-butyl titanate, tin octylate,
Lead octylate, cobalt octylate, zinc octylate,
Various metal-containing compounds such as calcium octylate, zinc naphthenate, cobalt naphthenate, di-n-butyltin diacetate, di-n-butyltin dioctoate, di-n-butyltin dilaurate or di-n-butyltin maleate; Or p-toluenesulfonic acid, trichloroacetic acid,
Examples thereof include various acidic compounds such as phosphoric acid, monoalkylphosphoric acid, dialkylphosphoric acid, monoalkylphosphorous acid and dialkylphosphorous acid.

In addition, in the crosslinkable urethane resin composition of the present invention, a compound having a hydrolyzable silyl group including the compound (A) may be used, if necessary.

Examples of this type of compound include various ethyl silicates such as tetraethyl silicate.
Examples thereof include isopropyl derivatives, isopropyl silicate derivatives or methyl silicate derivatives, and compounds generally called silane coupling agents. Also,
Specific examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4epoxycyclohexyl) ethyltrimethoxysilane, γ-methacryloxy. Propyltrimethoxysilane, γ-aminopropyltrimethoxysilane, N-β (aminoethyl)
γ-aminopropyltrimethoxysilane, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, γ- Examples include chloropropyltrimethoxysilane and the like.

The crosslinkable urethane resin composition of the present invention comprises
Since the crosslinking reaction easily progresses due to the water content and a strong crosslinked cured product is produced, it can be used in various applications such as artificial leather, synthetic leather, adhesives, sealing agents, coating agents, films and sheets. . In particular, it has excellent adhesive strength and durability in adhesive applications, and in the application of artificial leather or synthetic leather, the resin does not elute in the toluene extraction treatment step and the artificial appearance is extremely good. Leather or synthetic leather is obtained. Further, in the present invention, it is not necessary to leave an isocyanate group in the resin or use an isocyanate compound as a cross-linking agent, so that the problem of toxicity during work can be completely avoided, and a composition with very good safety and In addition, since the crosslinkability is dramatically improved as compared with the conventional one, the composition is extremely useful in practice.

[0039]

EXAMPLES The embodiments of the present invention will now be described with reference to specific examples, but the present invention is not limited to these examples. The parts and% in the examples relate to weight unless otherwise specified.

[Method of forming a film] The polyurethane resin solution or the compound was cast on a release paper and dried at 80 ° C for 30 minutes to form a film having a thickness of about 50 µm.

[Measurement Method of Adhesive Strength with Steel Plate] A polyurethane resin composition is applied by a bar coater onto a steel plate degreased with acetone (6 g / m ² ). It is heated in a dryer at 195 ° C. for 1 minute and then immediately passed through a hot roll at 120 ° C. to laminate a vinyl chloride sheet. After 24 hours, the peel strength of the PVC sheet is examined.

[Solubility in Tetrahydrofuran] The film prepared by the above method is cut into 5 cm squares, placed in a flask with 100 ml of tetrahydrofuran, and heated at 50 ° C. for 5 hours to observe the state.

[Tensile Strength of Film] The film produced by the above method was measured by the method according to JIS K-6505.

[Crosslinking Method Using Polyisosonate Crosslinking Agent] TDI based on 100 parts by weight of the urethane resin solution.
10 parts of a polyisoisoatenate-based cross-linking agent (Krisbon NX manufactured by Dainippon Ink and Chemicals, Inc.) and 3 parts of a catalyst (Krisbon Accel HM manufactured by Dainippon Ink and Chemicals, Inc.) were mixed and uniformly mixed before use.

[Detection Method of Free Isocyanate Monomer] 100 mg of a urethane resin solution was dissolved in 20 cc of THF, an excess amount of butylamine was added, and measurement was carried out by high performance liquid chromatography.

Example 1, Comparative Example 1 and Comparative Example 2 100 parts of sebacic acid / isophthalic acid / ethylene glycol / neopentyl glycol polyester diol having a molecular weight of 2,000, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane 3 Parts, diphenylmethane diisocyanate 49 parts, stannous octylate 0.0
After mixing 5 parts and 110 parts of toluene and reacting at 70 ° C. for 2 hours, 263 parts of methyl ethyl ketone and 8 parts of ethylene glycol are added and reacted at 70 ° C. for 12 hours, and further 3 parts of methanol are added and at 60 ° C. for 1 hour. By reacting, a polyurethane resin solution having a resin concentration of 30% and a viscosity of 7,000 centipoise was obtained. The content of the free isocyanate monomer in the resin solution was measured using a part of the obtained resin solution. Next, 0.5% by weight of dibutyltin dilaurate (DBTL) was added and mixed as a crosslinking catalyst to the polyurethane resin content, and the adhesive strength to the steel sheet and the solubility to tetrahydrofuran were examined by the above-mentioned method. A polyurethane resin having the same composition except that N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane was not used was synthesized and a comparative test was conducted (Comparative Example 1).
Further, a comparative test (Comparative Example 2) was conducted in which the polyurethane resin used in Comparative Example 1 was crosslinked with a TDI-based crosslinking agent.

[0047]

[Table 1]

From the above results, N-β (aminoethyl) γ
-The polyurethane resin using aminopropylmethyldimethoxysilane was insoluble in tetrahydrofuran because it had stronger adhesion to the steel sheet and was cross-linked as compared with the polyurethane resin not using it. Further, a polyurethane resin having a hydrolyzable silyl group in its side chain is superior in adhesive strength to a steel plate and is a highly toxic free isocyanate monomer as compared with a type using a normal polyurethane resin and a polyisosonate-based crosslinking agent. It was confirmed that the content was low.

Example 2, Comparative Example 3 and Comparative Example 4 Polyhexylene adipate diol 10 having a molecular weight of 2,000
After mixing 0 parts, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane 5 parts, diphenylmethane diisocyanate 36 parts, stannous octylate 0.04 parts toluene 83 parts and reacting at 70 ° C. for 2 hours,
370 parts of methyl ethyl ketone and 8 parts of 1,6 hexanediol were added and reacted at 70 ° C for 12 hours, and further 3 parts of methanol were added and reacted at 60 ° C for 1 hour to prepare a polyurethane resin solution having a resin concentration of 25% and a viscosity of 6,500 centipoise. Obtained. The content of the free isocyanate monomer in the resin solution was measured using a part of the obtained resin solution. Then, 0.5% by weight of dibutyltin dilaurate (DBTL) was added and mixed as a crosslinking catalyst to this polyurethane resin solution, and the adhesive strength to a steel plate and the solubility to tetrahydrofuran were examined by the above method. Further, a polyurethane resin having the same composition except that N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane was not used was synthesized and a comparative test was conducted (Comparative Example 3). Also, a comparative test in which the polyurethane resin used in Comparative Example 3 was cross-linked with a TDI-based cross-linking agent (Comparative Example 4).
I went. The results are shown in Table 2.

[0050]

[Table 2]

From the above results, N-β (aminoethyl) γ
-The polyurethane resin using aminopropylmethyldimethoxysilane was insoluble in tetrahydrofuran because it had stronger adhesion to the steel sheet and was cross-linked as compared with the polyurethane resin not using it. Further, a polyurethane resin having a hydrolyzable silyl group in its side chain is superior in adhesive strength to a steel plate and is a highly toxic free isocyanate monomer as compared with a type using a normal polyurethane resin and a polyisosonate-based crosslinking agent. It was confirmed that the content was low.

Example 3, Comparative Example 5 and Comparative Example 6 Polybutylene adipate diol 100 having a molecular weight of 2,000
Parts, N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane 5 parts, diphenylmethane diisocyanate 49 parts, stannous octylate 0.05 parts, and toluene 110 parts were mixed and reacted at 70 ° C. for 2 hours, 285 parts of methyl ethyl ketone and 8 parts of ethylene glycol were added and reacted at 70 ° C. for 12 hours, and further 3 parts of methanol were added and reacted at 60 ° C. for 1 hour to obtain a polyurethane resin solution having a resin concentration of 30% and a viscosity of 7,000 centipoise. The content of the free isocyanate monomer in the resin solution was measured using a part of the obtained resin solution. Then, 0.5 wt% of dibutyltin dilaurate (DBTL) was added and mixed as a crosslinking catalyst to this polyurethane resin solution, and the tensile strength of the film and the solubility in tetrahydrofuran were examined by the above-mentioned method. A polyurethane resin having the same composition except that N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane was not used was synthesized and a comparative test was conducted (Comparative Example 5). Further, a comparative test (Comparative Example 6) was conducted in which the polyurethane resin used in Comparative Example 5 was crosslinked with a TDI-based crosslinking agent. The tensile strength and solubility in tetrahydrofuran of the film obtained from this polyurethane resin solution were examined. The results are shown in Table 3.

[0053]

[Table 3]

From the above results, N-β (aminoethyl) γ
-The polyurethane resin using aminopropylmethyldimethoxysilane had higher tensile strength than the polyurethane resin not using it and was insoluble in tetrahydrofuran because it was crosslinked. From the above results, the polyurethane resin having a hydrolyzable silyl group in the side chain has a superior adhesive force to a steel plate and a highly toxic free release compared to the type using a normal polyurethane resin and a polyisosonate cross-linking agent. It was confirmed that the content of the isocyanate monomer was low.

Example 4 70 parts of adipic acid / 1,4BG polyester diol having a molecular weight of 2,000 and PTMG30 having a molecular weight of 2000
Parts, ethylene glycol 10 parts dimethylformamide (DMF) 394 parts, and N-β (aminoethyl) γ-aminopropyltrimethoxysilane 3 parts in a 1 L four-necked flask and uniformly dissolved. 56 parts of diphenylmethane diisocyanate was added with vigorous stirring, and the temperature was 70 ° C.
React for 10 hours at polyurethane solution (resin concentration 3
0.0%, viscosity 950 ps / 25 ° C.) was obtained. The content of the free isocyanate monomer in the resin solution was measured using a part of the obtained resin solution, but no free isocyanate monomer was detected.

Then, dimethylformamide was added to this polyurethane solution so that the resin concentration became 20%, and 0.5% by weight of dibutyltin dilaurate (DBTL) was added and mixed as a crosslinking catalyst to the polyurethane resin content.
It was cast on a polyethylene terephthalate (PET) sheet so that the thickness was about 1 mm. It was immersed in an aqueous solution containing 50% dimethylformamide at 50 ° C. for 20 minutes to be solidified. Then, after thoroughly washing in 40 ° C. warm water, it was dried in a 100 ° C. hot air dryer for 30 minutes to obtain a porous layer sheet.

The smoothness of the surface of the sheet is good,
The apparent specific gravity was 0.472, and when the sheet cross section was observed, it had uniformly dispersed fine pores. Further, the film-forming sheet was immersed in toluene at 90 ° C. for 1 hour as a toluene extraction treatment for producing ultrafine fiber artificial leather, then washed with hot water at 90 ° C. for 1 hour, and dried at 80 ° C. for 30 minutes. The surface condition is smooth, the weight loss after drying is 0.5%,
The area retention rate was 99.5%, and it had excellent performance as a urethane resin for artificial leather which was treated with hot toluene and made a nonwoven fabric an ultrafine fiber. It was confirmed that this sheet was insoluble in DMF and crosslinked.

Comparative Example 7 N-β (aminoethyl) γ-used in Example 4
A polyurethane solution was prepared in the same manner as in Example 1 except that 1 part of ethylene glycol was used instead of aminopropyltrimethoxysilane and the crosslinking catalyst DBTDL used in Example 1 was not used (resin concentration 30.0%,
A viscosity of 950 ps / 25 ° C.) was obtained. This polyurethane solution was wet-coated as in Example 1 to give an apparent specific gravity of 0.4.
A porous layer sheet having a smooth surface of No. 75 was obtained. Further, as a result of conducting a heat-resistant toluene test in the same manner as in Example 1, the weight loss was as large as 5.5% because it was not crosslinked, and the area retention rate was 96.5%. It could not be used for artificial leather which is treated with toluene and made a non-woven fabric into ultrafine fibers. This sheet was soluble in DMF.

[0059]

EFFECTS OF THE INVENTION According to the present invention, a urethane resin exhibiting excellent wet crosslinkability without volatilizing a harmful isocyanate compound at the time of use, and an excellent worker safety and strong crosslinkability It is possible to provide a crosslinkable urethane resin composition from which a cured product is obtained.

In particular, the composition of the present invention has extremely good cross-linking curability and is excellent in strength, adhesive strength, durability and solvent resistance of the cured product, so that artificial leather, synthetic leather, adhesives, sealing agents, It is extremely useful in applications such as coating agents, films and sheets.

Claims (10)

[Claims] 1. A compound (A) having two functional groups having active hydrogen atoms per molecule and having a hydrolyzable silyl group, and a long-chain polyhydroxy compound (B).
And the organic polyisocyanate (C) are reacted as an essential raw material component, which is a method for producing a crosslinkable urethane resin. 2. A compound (A) having two functional groups having active hydrogen atoms per molecule and having a hydrolyzable silyl group is added in an amount of 0.1 based on the total weight of the raw material components.
The method according to claim 1, wherein the reaction is carried out at a ratio of about 30% by weight. 3. The production method according to claim 1 or 2, wherein the reaction is further carried out by using a chain extender (D) in combination. 4. The production method according to claim 1, wherein the reaction temperature is 30 to 250 ° C. 5. The compound (A) having two functional groups having active hydrogen atoms per molecule and having a hydrolyzable silyl group is a hydrolyzable compound having two amino groups per molecule. It is a silyl group containing compound, The manufacturing method as described in any one of Claims 1-4. 6. The long-chain polyhydroxy compound (B) is
The production method according to claim 5, which is a polyester polyol or a polyether polyol. 7. A crosslinkable urethane resin composition comprising a urethane resin having a hydrolyzable silyl group in a side chain and an organic solvent as essential components. 8. The urethane resin has a number average molecular weight of 50,0.
The composition according to claim 7, which is from 00 to 500,000. 9. The content of hydrolyzable silyl groups in the urethane resin is 0.8 to 5 on average per one molecule of the urethane resin.
The composition according to claim 7 or 8, which is 0 in number. 10. The composition according to claim 7, 8 or 9, which further contains a condensation catalyst.