JP2002317113A - Method for preparing polyurethane resin solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for preparing a polyurethane resin solution suitable for use in various ways, transparent and high in adhesion stability, free of discoloring or thickening, and not suffering thermal depolymerization. SOLUTION: The method is characterized in that a phenol compound having a number-average molecular weight of 600 or more is added upon completion of a reaction in an organic solvent among (a) an organic diisocyanate, (b) a high-molecular diol having a molecular weight of 500-5,000, (c) a low-molecular diol having a molecular weight of 300 or less, and (d1) a monohydric alcohol having a molecular weight of 200 or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a polyurethane resin solution.

More specifically, the present invention relates to a method for producing a polyurethane resin solution by a batch method, which has excellent solution stability,
The present invention relates to a method for producing a polyurethane resin solution that can be suitably used for various applications.

[0003]

2. Description of the Related Art Conventionally, a polyurethane resin solution having substantially no cross-linking structure is used to prepare elastic fibers, elastic films, various elastomer-like molded articles, surface coatings such as artificial leather surface films and various paints, and impregnating agents. Various articles having excellent rubber-like elasticity have been manufactured. This polyurethane resin solution is generally produced by reacting an organic diisocyanate with a relatively high molecular weight diol and a chain extender in a polar solvent, and thereafter, a molded article is produced by removing the solvent.

However, the instability of the polyurethane resin solution, such as depolymerization and the decrease in viscosity when the solution is heated or stored for a long period of time after the production of the polyurethane resin solution, is caused by the moldability and physical properties of the subsequent molded product. There are various problems to be solved in order to industrially produce products efficiently, such as reducing the water content and limiting the pot life of the polyurethane resin solution.

[0005] In order to solve these problems, as a method for stabilizing the viscosity of a polyurethane resin solution, for example,
Japanese Patent Publication No. 41-3472 discloses a method of adding an amine and an organic acid or an amine salt of an organic acid, and Japanese Patent Publication No. 44-23211 discloses a chain extension reaction in a polar solvent containing water. Is disclosed, and Japanese Patent Publication No. Sho 4
JP-A-9-40006 discloses a method using an alicyclic diamine, aromatic dimethylamine, and a substituted iminobisaliphatic amine, and JP-A-47-15498 discloses a method using metal acetylacetone. JP 4
JP-A-8-12347 discloses a method using lithium formate, sodium acetylacetone or the like.
JP-139514 discloses a method using a lithium salt, an aliphatic or alicyclic chain terminator.
-279415 discloses a method using a symmetric diamine and an asymmetric diamine.
Japanese Patent Publication No. 98 discloses a method for specifying conditions for adding a hydrazine or diamine solution. However, although these methods slightly improve the stability of viscosity, they have not yet reached a satisfactory level.

The stabilization of the viscosity of a polyurethane resin solution during heating is described in Japanese Patent Publication No. 47-35317.
A method is disclosed in which the amount of a chain extender is set to be equal to or less than the equivalent of an isocyanate (hereinafter, abbreviated as NCO) group, and the remainder is chain-extended with water, but the viscosity decreases until the viscosity becomes stable,
There is a disadvantage that the stabilized viscosity is about half of the viscosity immediately after synthesis, and it is hardly satisfactory.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyurethane resin solution which is transparent, has good viscosity stability and does not depolymerize even when heated or stored for a long period of time, which can be suitably used for various applications. It is an object of the present invention to provide a method for producing the same.

[0008]

The method for producing a polyurethane resin solution of the present invention employs the following means to solve the above-mentioned problems.

That is, an organic diisocyanate (a),
After reacting a high molecular diol (b) having a number average molecular weight of 500 or more and 5000 or less and a low molecular diol (c) having a molecular weight of 300 or less in an organic solvent, a phenolic compound (d) is added. This is a method for producing a polyurethane resin solution.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the organic diisocyanate (a) is an aromatic diisocyanate having 6 to 20 carbon atoms (excluding the carbon in the NCO group, the same applies hereinafter) and an aliphatic diisocyanate having 2 to 18 carbon atoms. , Carbon number 4-1
Preferred are an alicyclic diisocyanate of 5, an araliphatic diisocyanate having 8 to 15 carbon atoms, modified products of these diisocyanates (carbodiimide modified products, urethane modified products, uretdione modified products, etc.), and mixtures of two or more of these.

Specific examples of the aromatic diisocyanate include 1,3-phenylene diisocyanate and 1,4-phenylene diisocyanate.
Phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,
4'-diphenylmethane diisocyanate, 4,4'-
Diphenylmethane diisocyanate (hereinafter abbreviated as MDI), 4,4′-diisocyanatobiphenyl,
Preferred are 3'-dimethyl-4,4'-diisocyanatobiphenyl, 3,3'-dimethyl-4,4'-diisocyanatodiphenylmethane, 1,5-naphthylene diisocyanate and the like.

Specific examples of the aliphatic diisocyanate include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and 2,6-diisocyanatomethyl Preferred are proate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate and the like.

Specific examples of the alicyclic diisocyanate include isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, and bis (2-isocyanatoethyl) -4-cyclohexylene-isocyanate. 1,2-dicarboxylate, 2,5-
Norbornane diisocyanate, 2,6-norbornane diisocyanate and the like are preferred.

Specific examples of the araliphatic diisocyanate include m-xylylene diisocyanate, p-xylylene diisocyanate, and α, α, α ′, α′-tetramethylxylylene diisocyanate.

Of these, aromatic diisocyanates are particularly preferred from the viewpoint of improving the strength of the final product and obtaining excellent heat resistance in various applications, and particularly, MDI.
Is preferred.

The polymer diol (b) used in the present invention
For example, polyalkylene ether diol (b1), polyester diol (b2), polybutadiene diol (b3), and a mixture of two or more thereof are preferably used.

The number average molecular weight of the high molecular diol (b) is
500-5000. Preferably 700-4500
And more preferably from 1,000 to 4,000.

Polyalkylene ether diol (b1)
Preferred are compounds having a structure in which an alkylene oxide (hereinafter abbreviated as AO) is added to a dihydric alcohol, and a mixture of two or more of these.

Examples of the dihydric alcohol include ethylene glycol (hereinafter abbreviated as EG), propylene glycol, 1,3-butylene glycol, 1,4-
Butanediol (hereinafter abbreviated as 14BG), 1,6
-Hexanediol, diethylene glycol (hereinafter referred to as D
EG), an aliphatic dihydric alcohol having 2 to 12 carbon atoms such as neopentyl glycol and dodecanediol, or a 6 to 10 carbon atom such as 1,4-cyclohexanediol and bis (hydroxymethyl) cyclohexane. Alicyclic dihydric alcohol, or, for example, xylylene glycol, bis (hydroxyethyl)
An aromatic ring-containing dihydric alcohol having 8 to 20 carbon atoms, such as benzene, bis (hydroxyethoxy) benzene, and an ethylene oxide adduct of bisphenol A, is preferred. 2
It is also preferable to use two or more kinds of the hydric alcohols.

The AO to be added to the dihydric alcohol includes
Ethylene oxide (hereinafter abbreviated as EO), propylene oxide (hereinafter abbreviated as PO), 1,2-butylene oxide, 2,3-butylene oxide,
3-butylene oxide, tetrahydrofuran (hereinafter, referred to as
Preferred are THF, which is abbreviated as THF), 3-methyltetrahydrofuran (hereinafter, abbreviated as 3M-THF), styrene oxide, α-olefin oxide, epichlorohydrin, and the like.

AO may be used alone or in combination of two or more.
In the case of a combination of two or more, a chip type, a balance type, an active secondary type or the like may be added with a block or a random addition, or a mixed system of a block addition and a random addition may be used. , That is, preferably 0 to 50% by weight, more preferably 5 to 40% by weight of ethylene oxide chains are randomly distributed in the molecule, preferably 0 to 30% by weight, more preferably 5 to 25% by weight. An ethylene oxide chain may be capped at the molecular terminal.

Among these AOs, in various applications, the elongation of the final product is increased and the flexibility is high.
From the viewpoint of enhancing the recoverability, especially, only THF alone, E
The combination of O and THF and the combination of THF and 3M-THF (in the case of combination, random addition, block addition, or a mixture of both) are preferred.

Polyalkylene ether diol (b1)
Specific examples of polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol (hereinafter abbreviated as PTMG), poly-3-methyltetramethylene ether glycol, THF / EO copolymer diol, and THF / 3M-THF copolymer diol Are preferred. Of these, PTMG, THF / EO copolymer diol, THF / 3M-THF copolymer diol, and the like are particularly preferable.

The addition of AO to the dihydric alcohol can be carried out by a usual method, and can be carried out without a catalyst or in the presence of a catalyst (such as an alkali catalyst, an amine catalyst, or an acidic catalyst) (particularly in the latter half of the AO addition). ) Is preferably carried out in one or more stages under normal pressure or under pressure.

Polyalkylene ether diol (b1)
Number average molecular weight (calculated from OH value) of 500 to 500
0. Preferably it is 700-4500, More preferably, it is 1000-4000.

The primary hydroxyl group content of the polyalkylene ether diol (b1) is preferably from the viewpoint of improving reactivity even when a catalyst is not used and preventing problems such as residual catalyst due to addition of a catalyst. 0 to 100%, more preferably 30 to 100%, still more preferably 50 to 100%, and most preferably 70 to 100%.
100%.

The polyester diol (b2) includes a condensed polyester diol obtained by reacting a dihydric alcohol and / or a polyalkylene ether diol having a molecular weight of 1,000 or less with a dicarboxylic acid, and a polylactone diol obtained by ring-opening polymerization of a lactone. It is preferable to include a polycarbonate diol obtained by reacting a dihydric alcohol with a carbonic acid diester of a lower alcohol (such as methanol).

The dihydric alcohol is preferably the same as the dihydric alcohol exemplified as the starting material for the polyalkylene ether diol (b1).

The polyalkylene ether diol having a molecular weight of 1,000 or less is preferably polytetramethylene ether glycol, polypropylene glycol, polyethylene glycol, or a mixture of two or more of these.

The dicarboxylic acids include succinic acid,
C2 to C12 aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and dodecanoic acid, terephthalic acid, isophthalic acid, and phthalic acid such as aromatic dicarboxylic acids having 8 to 115 carbon atoms; Ester-forming derivatives (acid anhydrides, lower alkyl esters having 1 to 4 carbon atoms, etc.) and mixtures of two or more of these. Lactones include ε-caprolactone, γ
-Butyrolactone, γ-valerolactone, and mixtures of two or more thereof are preferred.

The polyesterification is carried out in a conventional manner, for example,
A method of reacting (condensing) a dihydric alcohol and / or a polyether diol having a molecular weight of 1000 or less with a dicarboxylic acid or an ester-forming derivative thereof, or an anhydride thereof and AO (for example, EO and / or PO), or It can be achieved by a method of adding a lactone to an agent (low molecular diol and / or polyether diol having a molecular weight of 1000 or less).

Specific examples of these polyester diols (b2) include polyethylene adipate diol, polybutylene adipate diol, polyhexamethylene adipate diol, polyneopentyl adipate diol, polyethylene propylene adipate diol, polyethylene butylene adipate diol, and polybutylene hexade. Methylene adipate diol, polydiethylene adipate diol, poly (polytetramethylene ether)
Adipate diol, polyethylene azelate diol, polyethylene sebacate diol, polybutylene azelate diol, polybutylene sebacate diol,
Polycaprolactone diol, polyester diol synthesized from 3 methylpentanediol and an aliphatic dicarboxylic acid having 2 to 20 carbon atoms, polyhexamethylene carbonate diol, and the like are preferable.

The number average (calculated from the OH number) molecular weight of the polyester diol (b2) is from 500 to 5,000. Preferably it is 700-4500, More preferably, it is 1000-4000.

Examples of the polybutadiene diol (b3) include those having a 1,2-vinyl structure, those having a 1,2-vinyl structure and a 1,4-trans structure, and those having a 1,4-trans structure. preferable. 1,2
It is also preferred that the ratio between the -vinyl structure and the 1,4-trans structure be varied, for example, preferably 10 mol
0: 0 to 0: 100. The polybutadiene glycol (b3) also includes homopolymers and copolymers (such as styrene-butadiene copolymer and acrylonitrile-butadiene copolymer), and hydrogenated products thereof. The hydrogenation rate of such a hydrogenated product is preferably 20 to 100%. It is.

The number average (calculated from the OH value) molecular weight of the polybutadiene diol (b3) is from 500 to 5,000. Preferably it is 700-4500, More preferably, it is 1000-4000.

Preferred as the polymer diol (b) is a polyalkylene ether diol (b1), and particularly preferred are PTMG, a THF / EO copolymerized diol and a THF / 3M-THF copolymerized diol.

The low molecular weight diol (c) used in the present invention
As, for example, EG, propylene glycol, 1,
3-propanediol (hereinafter abbreviated as 3G), 1,
Aliphatic glycols having 2 to 8 carbon atoms such as 3-butylene glycol, 14BG, 1,6-hexanediol, DEG, neopentyl glycol, and the like, for example, 1,4-cyclohexanediol, 1,4-bis (hydroxymethyl)
An alicyclic diol having 6 to 10 carbon atoms such as cyclohexane, for example, an aromatic compound having 8 to 20 carbon atoms such as xylylene glycol, bis (hydroxyethyl) benzene, bis (hydroxyethoxy) benzene, and an ethylene oxide adduct of bisphenol A Ring-containing diols and the like are preferred. Among these, aliphatic glycols are preferable, and EG, DEG, and 1 are more preferable, from the viewpoint of obtaining a final product having high strength and high physical properties excellent in heat resistance, light resistance, and the like.
4BG, 3G, and more preferably EG, 14
BG and 3G.

The molecular weight of the low molecular weight diol (c) is 300
The following is preferred, and more preferably 62 to 120.

The present invention relates to a method wherein the organic diisocyanate (a), the high molecular diol (b) and the low molecular diol (c) are reacted in an organic solvent, and then a phenolic compound (d) is added. It is.

If the phenolic compound (d) is not added after the organic diisocyanate (a), the high molecular diol (b) and the low molecular diol (c) are reacted in an organic solvent, a urethane bond is formed. When a side reaction such as an allophanate bond or a urea bond generated by the reaction of an NCO group and a buret bond generated by a reaction of the NCO group with the urea bond occurs simultaneously with the urethanization reaction, when the polyurethane resin solution is heated or stored for a long period of time, Problems such as a decrease in the viscosity and a decrease in the molecular weight of the polyurethane resin solution become a problem, and the yield decreases when the solvent is removed from the polyurethane resin solution to produce a molded product, and the quality of the obtained molded product becomes poor. There's a problem.

Examples of the phenolic compound (d) used in the present invention include "Sumilyzer" (registered trademark) GA80 manufactured by Sumitomo Chemical Co., Ltd. and "Cyanox" (registered trademark) 179 manufactured by Scitech Japan Limited.
0, a copolymer of divinylbenzene and p-cresol and the like are preferred.

In the present invention, the molecular weight of the phenolic compound is preferably 600 or more from the viewpoint of preventing volatilization in the subsequent heating and drying step.

Further, in the present invention, a tertiary amine compound (e) is preferably added. The tertiary amine is preferably added after the organic diisocyanate (a), the high molecular diol (b) and the low molecular diol (c) are reacted in an organic solvent. The addition of the tertiary amine compound (e) may be simultaneous with, or before or after the addition of the phenolic compound.

The molecular weight of the tertiary amine compound (e) is preferably 280 or more from the viewpoint of obtaining stability against coloring.

As the organic solvent used in the present invention, for example, N, N-dimethylformamide (hereinafter abbreviated as DMF), N, N-dimethylacetamide (hereinafter D)
MAC), amide solvents such as N-methylpyrrolidone, sulfoxide solvents such as dimethyl sulfoxide, ketone solvents such as methyl ethyl ketone, ether solvents such as dioxane and THF, methyl acetate, ethyl acetate, butyl acetate and the like. Ester solvents, toluene,
Aromatic solvents such as xylene and the like and mixtures of two or more thereof are preferred. Of these, preferred are amide solvents, and particularly preferred is DMF or DMAC, or a mixture of DMF and DMAC.

In the present invention, from the viewpoints of easily obtaining a resin having a desired viscosity and molecular weight, improving the viscosity stability of the polyurethane resin solution, and improving the strength of the obtained resin, the organic diisocyanate ( a) and
The equivalent ratio with the active hydrogen group-containing compound composed of the high molecular diol (b) and the low molecular diol (c) is preferably 0.9.
5: 1 to 1.1, more preferably 0.97: 1 to 1
1.05: 1.

The equivalent ratio of the high molecular diol (b) to the low molecular diol (c) is preferably 1: 0.5 to 1: 8 from the viewpoint of improving the resin strength and elongation.
More preferably, it is 1: 0.8 to 1: 5.

The concentration of the resin component in the polyurethane resin solution is set to the target solution viscosity, and it is possible to prevent the viscosity stability from being deteriorated due to aging and to obtain a variety of uses, storability and delivery property. Therefore, it is preferably 30 to 50% by weight, more preferably 37 to 45% by weight.

The reaction temperature may be the same as that usually used for the polyurethane reaction, preferably 20 to 100 ° C, more preferably 40 to 80 ° C.

The viscosity of the obtained polyurethane resin solution (2
0 ° C) is preferably 500,000 to 15 from the viewpoints of versatility of use, storability, delivery properties and viscosity stability.
00000 mPa · s, more preferably 6,000 mPa · s.
It is 00 to 1300000 mPa · s.

In order to accelerate the reaction, it is also preferable to use a catalyst which is usually used for a polyurethane reaction, if desired.

Preferred examples of the catalyst include amine catalysts such as triethylamine and triethylenediamine, and tin catalysts such as dibutyltin dilaurate and dioctyltin dilaurate.

The amount of the catalyst used is preferably 1% by weight or less based on the polyurethane resin.

In the present invention, the polyurethane resin solution may optionally contain a coloring agent such as titanium oxide, various stabilizers such as an ultraviolet absorber and an antioxidant, an inorganic filler, an organic modifier, and other additives. Preferably.

The polyurethane resin solution obtained by the production method of the present invention can be widely used for various uses.

Typical applications include artificial leather, synthetic leather, various coating materials, elastic fibers and the like.

[0057]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. Parts in Examples and Comparative Examples represent parts by weight, and% represents% by weight.

The viscosity, solution viscosity stability, and
The evaluation of the number average molecular weight of the resin, the production of the film, the physical properties of elasticity and elasticity of the film, and the elastic recovery were performed according to the following methods. (1) Viscosity After adjusting the temperature of the sample (polyurethane resin solution) in a thermostat at 20 ° C. for 5 hours, a B-type viscometer [Toki Sangyo Co., Ltd.
H-type viscometer]. (2) Solution viscosity stability A sample (polyurethane resin solution) was placed in a 40 ° C.
After the storage, the temperature was adjusted to 20 ° C. and the viscosity was measured. (3) Number average molecular weight HLC-8020 manufactured by Tosoh Corporation (column: Tosoh G)
MH-XL). (4) Preparation of Film A polyurethane resin solution was placed on a glass plate subjected to mold release treatment.
It was applied to a thickness of 7 mm, dried for 3 hours with a circulating drier at 70 ° C., and then peeled off from the glass plate to form a film having a thickness of about 0.2 mm. (5) Tensile properties After leaving the film to be measured at room temperature for 3 days,
The strength and elongation characteristics were measured according to SK-6301. (6) Elastic recovery rate After leaving the film to be measured at room temperature for 3 days, the film was cut into 1 cm x 9 cm, and marked lines were drawn at intervals of 5 cm in the length direction to obtain test samples.

Next, the sample was pulled using an Autograph AGS-500D manufactured by Shimadzu Corporation at a pulling speed of 200 mm / mm.
After stretching for 300 minutes and holding for 2 minutes, the tension was removed and the elastic recovery was measured.

Example 1 A four-necked flask equipped with a stirrer and a thermometer was charged with 310 parts of PTMG having a number average molecular weight (calculated from the OH value) of 3,100 and EG1 having a molecular weight of 62.
6.3 parts, 91.5 parts of MDI and 577 parts of DMAC were charged and reacted at 70 ° C. for 7 hours under a dry nitrogen atmosphere.
Next, 13.1 parts of n-butyl alcohol was added (the free NCO content in the reaction system at this time was (in terms of resin solid content)
After the end termination reaction was performed for 1 hour, 1 part of "Sumilyzer" (registered trademark) GA80 (molecular weight: 741) manufactured by Sumitomo Chemical Co., Ltd., t-butyldiethanolamine and methylene-bis Reaction product of-(4-cyclohexyl isocyanate) (number average molecular weight: 4
640) was added, and the resin concentration was 42%, the viscosity was 710,
000 mPa · s / 20 ° C., number average molecular weight 66,000
Was obtained. The obtained polyurethane resin solution was stored at 40 ° C. for 20 days, but no particular change in viscosity or turbidity occurred. The polyurethane resin solution was coated on glass and dried at 70 ° C. for 3 hours to form a film. Table 1 shows the physical properties of the obtained film.
The surface had good characteristics without irregularities.

Example 2 In the same reaction vessel as used in Example 1, a number average (calculated from OH value) molecular weight 3,
500 THF / 3M-THF (mol% ratio: 85/1)
5) EG2 having a copolymerized diol of 350 parts and a molecular weight of 62
4.8 parts, 126 parts of MDI and 784 parts of DMAC were charged and reacted at 70 ° C. for 8 hours under a dry nitrogen atmosphere. Then, 13.1 parts of n-butyl alcohol was added (the content of free NCO in the reaction system at this time). Is (in terms of resin solids)
After the end termination reaction was performed for 1 hour, 1 part of "CYANOX" (registered trademark) 1790 (molecular weight: 699) manufactured by Cytec Japan Limited and t-butyldiethanolamine and methylene-bis One part of the reaction product of-(4-cyclohexyl isocyanate) (number average molecular weight: 4640) was added, and the
A polyurethane resin solution having 9%, a viscosity of 700,000 mPa · s / 20 ° C. and a number average molecular weight of 63,000 was obtained. The obtained polyurethane resin solution was stored at 40 ° C. for 20 days, but no particular change in viscosity or turbidity occurred. The polyurethane resin solution was coated on glass and dried at 70 ° C. for 3 hours to form a film. Table 1 also shows the physical properties of the obtained film. The surface had good characteristics without irregularities.

Example 3 In the same reaction vessel as used in Example 1, a number average (calculated from OH value) molecular weight 2,
290 parts of a THF / EO (mol% ratio: 90/10) copolymerized diol of 900, 17.7 parts of EG having a molecular weight of 62,
97.5 parts of MDI and 583 parts of DMAC were charged and reacted at 70 ° C. for 9 hours under a dry nitrogen atmosphere. Then, 13.1 parts of n-butyl alcohol was added (the content of free NCO in the reaction system was (resin 0.041 (in terms of solid content)
%), 1 part of a condensation polymer of p-cresol and divinylbenzene (number average molecular weight: 1220) and t-butyldiethanolamine and methylene-bis- (4-cyclohexyl isocyanate). Of a reaction product (number average molecular weight: 4640) was added, and the resin concentration was 41% and the viscosity was 850,000 mPa ·
A polyurethane resin solution having a number average molecular weight of 56,000 at s / 20 ° C. was obtained. The obtained polyurethane resin solution was added to 40
After storage at 20 ° C. for 20 days, no particular change in viscosity or turbidity occurred. The polyurethane resin solution was coated on glass and dried at 70 ° C. for 3 hours to form a film. Table 1 also shows the physical properties of the obtained film. The surface had good characteristics without irregularities.

Example 4 A four-necked flask equipped with a stirrer and a thermometer was charged with 310 parts of PTMG having a number average molecular weight (calculated from the OH value) of 3,100 and EG1 having a molecular weight of 62.
6.3 parts, 91.5 parts of MDI and 577 parts of DMAC were charged and reacted at 70 ° C. for 7 hours under a dry nitrogen atmosphere.
Next, 13.1 parts of n-butyl alcohol was added (the free NCO content in the reaction system at this time was (in terms of resin solid content)
After the termination reaction for 1 hour, 1 part of a condensation polymer of p-cresol and divinylbenzene (number average molecular weight: 1220) and t-butyldiethanolamine and methylene-bis- (4- Reaction product of cyclohexyl isocyanate) (number average molecular weight: 46)
40) was added, and the resin concentration was 41% and the viscosity was 710,0.
A polyurethane resin solution having a number average molecular weight of 66,000 was obtained at 00 mPa · s / 20 ° C. The obtained polyurethane resin solution was stored at 40 ° C. for 20 days.
No turbidity was observed. The polyurethane resin solution was coated on glass and dried at 70 ° C. for 3 hours to form a film. Table 1 shows the physical properties of the obtained film. The surface had good characteristics without irregularities.

[Comparative Example 1] A number average (calculated from OH value) molecular weight 3,
310 PTMG parts of 100, EG16.3 of molecular weight 62
, 91.5 parts of MDI and 577 parts of DMAC, and reacted at 70 ° C. for 7 hours in a dry nitrogen atmosphere. Then, 13.1 parts of n-butyl alcohol was added (at this time, the free NCO content in the reaction system was (In terms of resin solid content)
036%) for 1 hour and a polyurethane resin solution (H) having a resin concentration of 42%, a viscosity of 760,000 mPa · s / 20 ° C., and a number average molecular weight of 66,000.
2) was obtained. The obtained polyurethane resin solution (H2) was stored at 40 ° C. for 20 days to form a film. Since no phenolic compound was added at the beginning, the solution viscosity stability was poor, and the resulting film had low strength, low elongation, and low recoverability.

[0065]

[Table 1]

As is apparent from Table 1, the polyurethane resin solutions of Examples 1 to 4 of the present invention have remarkably good solution viscosity stability as compared with Comparative Example 1, and the obtained films also have high elongation properties. It was at the standard.

On the other hand, the polyurethane resin solution of Comparative Example 1 had poor solution viscosity stability and could not be put to practical use.

[0068]

The polyurethane resin solution obtained by the method of the present invention is excellent in solution viscosity stability, and retains almost the same solution properties even after storage for a long time as immediately after production.

The polyurethane resin solution obtained by the method of the present invention having the above effects can be used for various purposes, for example,
It is particularly useful as a raw material for artificial leather, synthetic leather, various coating materials, elastic fibers and the like.

Continued on the front page (72) Inventor Masao Umezawa 1-1-2 Sonoyama, Otsu City, Shiga Prefecture Toray Dupont Co., Ltd. EV207 GH01 HA05 4J034 BA08 CA04 CB03 CB07 CC03 CC12 CC26 CC45 CC61 CC62 CC67 DA01 DB03 DB04 DC02 DC12 DC35 DF01 DF02 DF11 DF12 DF15 DF20 DF21 DF22 DG02 HCDG HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC HC46 HC53 HC54 HC61 HC64 HC66 HC67 HC71 HC73 JA14 JA30 JA32 KC17 KD02 KD04 KD12 KE02 QA05 QC05 RA09

Claims (9)

[Claims] An organic diisocyanate (a), a high molecular diol (b) having a number average molecular weight of 500 or more and 5,000 or less, and a low molecular diol (c) having a molecular weight of 300 or less are reacted in an organic solvent, and then phenol is reacted. A method for producing a polyurethane resin solution, comprising adding a system compound (d). 2. The method for producing a polyurethane resin solution according to claim 1, wherein the phenolic compound (d) has a molecular weight of 600 or more. 3. The method for producing a polyurethane resin solution according to claim 1, wherein the phenolic compound (d) is a compound obtained by reacting divinylbenzene with p-cresol. 4. The method for producing a polyurethane resin solution according to claim 1, wherein a tertiary amine compound (e) is added. 5. A polyurethane resin solution having a resin concentration of 30.
The method for producing a polyurethane resin solution according to any one of claims 1 to 4, wherein the content is set to 50 to 50% by weight. 6. The viscosity of the polyurethane resin solution is 50,000.
The method for producing a polyurethane resin solution according to any one of claims 1 to 5, wherein the temperature is 0 to 1500000 mPa · s / 20 ° C. 7. The method for producing a polyurethane resin solution according to claim 1, wherein the organic diisocyanate (a) is diphenylmethane diisocyanate. 8. The polymer diol (b) is selected from the group consisting of polytetramethylene ether glycol, tetrahydrofuran / ethylene oxide copolymerized diol, and tetrahydrofuran / 3-methyltetrahydrofuran copolymerized diol. The method for producing a polyurethane resin solution according to any one of claims 1 to 7, wherein the polyurethane resin solution is at least one selected from the group consisting of: 9. The method for producing a polyurethane resin solution according to claim 1, wherein the organic solvent is N, N-dimethylformamide and / or N, N-dimethylacetamide. .