JP2002080553A - Method for producing polyurethane resin solution - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyurethane resin solution favorably usable widely in various applications, which is transparent and high in viscosity stability, getting neither discolored nor thickened, and also causes no depolymerization thereof. SOLUTION: This method for producing a polyurethane resin solution comprises reaction in an organic solvent among (a) an organic diisocyanate, (b) a high-molecular diol 500-5,000 in number-average molecular weight, (c) a low-molecular diol <=300 in molecular weight and (d1) a monohydric alcohol <=200 in molecular weight, wherein the amount of the monohydric alcohol (d1) is 0.001-0.03 equivalent based on the total of the high-molecular diol (b) and the low-molecular diol (c), and a monohydric alcohol (d2) is added to the reaction system at a point when the free isocyanate group content per resin comes to 0.01-0.1 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

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.

[0003] However, after the polyurethane resin solution is produced, the instability of the polyurethane resin solution is such that the transparent solution becomes cloudy, the viscosity increases, and when the solution is heated, depolymerization occurs and the viscosity decreases. ,
There are various problems to be solved in order to industrially produce products efficiently, such as lowering the moldability and physical properties of the subsequent molded product and limiting the pot life of the polyurethane resin solution.

[0004] In order to solve these problems, as a method for stabilizing the viscosity of a polyurethane resin solution, for example,
A method of adding an amine and an organic acid or an amine salt of an organic acid (Japanese Patent Publication No. 41-3472), a method of conducting a chain extension reaction in a polar solvent containing water (Japanese Patent Publication No. 44-22)
No. 311), a method for producing a polyurethane polymer solution using an alicyclic diamine, an aromatic dimethylamine and a substituted iminobisaliphatic amine (Japanese Patent Publication No. 49-40006), a method for producing a polyurethane polymer solution using metal acetylacetone. Manufacturing method (JP-A-47-15498);
A method of stabilizing a polyurea elastomer solution by adding lithium formate, sodium acetylacetone or the like (JP-A-48-12347), a polyurethane urea elastomer using a lithium salt, an aliphatic or alicyclic chain stopper, JP-A-3-139514), a polyurethane elastic fiber using a symmetric diamine and an asymmetric diamine (JP-A-3-279415), and a method for producing a polyurethane resin solution by specifying conditions for adding hydrazine and a diamine solution ( Japanese Patent Application Laid-Open No. 50-78698) is known, but although these methods slightly improve viscosity stability and hue, they have not yet been satisfied.

For stabilizing the viscosity of a polyurethane resin solution during storage under heat, Japanese Patent Publication No. 47-35317 discloses that the amount of a chain extender is equal to or less than the equivalent of an isocyanate (hereinafter abbreviated as NCO) group and the remainder is water. However, there is a drawback that the viscosity decreases until the viscosity is stabilized, and the stabilized viscosity is about half of the viscosity immediately after the synthesis. hard.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems and is transparent, has good viscosity stability, has no coloring or thickening, and can be suitably used for various applications. An object of the present invention is to provide a method for producing a polyurethane resin solution capable of obtaining a polyurethane resin solution that does not cause depolymerization.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, a decrease in physical properties of a solution such as coloring, thickening, and a decrease in thermal stability occurs simultaneously with a urethanization reaction. A side reaction, namely, an allophanate bond or a urea bond formed by reacting an NCO group with a urethane bond
It has been found that the formation of burette bonds generated by the reaction of the CO group causes an increase in viscosity during storage of the polyurethane resin solution and a decrease in stability during storage under heating. Furthermore, as a result of intensive studies on a method for reducing these side reactions, it was found that during the urethanization reaction, the NCO group undergoes a urethanization reaction in the presence of a specific amount of monohydric alcohol, and the NCO remaining in the reaction system at the end of the reaction. By terminating the reaction by adding an excess amount of monohydric alcohol or monoamine to the group, there is no decrease in solution physical properties such as coloring, thickening, heat stability, etc. The inventors have found that a polyurethane resin solution having no deterioration in physical properties can be obtained, and have reached the present invention.

That is, the process for producing a polyurethane resin solution of the present invention comprises the steps of: preparing an organic diisocyanate (a), a high molecular diol (b) having a number average molecular weight of 500 to 5,000, a low molecular diol (c) having a molecular weight of 300 or less; Molecular weight 2
When reacting a monohydric alcohol (d1) of not more than 00 in an organic solvent, the monohydric alcohol (d1) is 0 with respect to the total of the high molecular diol (b) and the low molecular diol (c). 0.001 to 0.03 equivalents, and the free isocyanate group content per resin
At the stage when the amount becomes 1 to 0.1% by weight, the monohydric alcohol (d
A method for producing a polyurethane resin solution, characterized by adding 2).

Alternatively, an organic diisocyanate (a), a high molecular diol (b) having a number average molecular weight of 500 to 5,000, a low molecular diol (c) having a molecular weight of 300 or less, and a monohydric alcohol (d1) having a molecular weight of 200 or less are used. When reacting in an organic solvent, the monohydric alcohol (d
1) in an amount of 0.001 to 0.03 equivalents relative to the total of the high molecular diol (b) and the low molecular diol (c), and the free isocyanate group content per resin is 0.1. A method for producing a polyurethane resin solution, wherein a monoamine (d3) is added at a stage where the content of the polyurethane resin becomes from 0.1 to 0.1% by weight.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, as the organic diisocyanate (a), those which have been conventionally used for producing polyurethane can be used. Such organic diisocyanates include aromatic diisocyanates having 6 to 20 carbon atoms (excluding carbon in the NCO group, the same applies hereinafter), and 2 to 2 carbon atoms.
To 18 aliphatic diisocyanates, alicyclic diisocyanates having 4 to 15 carbon atoms, araliphatic diisocyanates having 8 to 15 carbon atoms, modified products of these diisocyanates (modified carbodiimide, modified urethane, modified uretdione, etc.) and A mixture of two or more of these is included.

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,
Examples include 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 Proate, bis (2-isocyanatoethyl) carbonate, 2-isocyanatoethyl-2,6-diisocyanatohexanoate and the like can be mentioned.

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-
Examples include norbornane diisocyanate and 2,6-norbornane diisocyanate.

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

Of these, aromatic diisocyanates are preferred from the viewpoint of improving the strength of the final product and obtaining excellent heat resistance in various applications, and MDI is particularly 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
It is preferably from 500 to 5,000, more preferably from 700 to 4,500, and still more preferably from 1,000
0 to 4,000.

Polyalkylene ether diol (b1)
Examples thereof include 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 preferably used. It is also preferable to use two or more dihydric alcohols in combination.

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
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 kinds, a block type or a random type such as a chip type, a balance type, and an active secondary type may be added, 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 arbitrarily distributed in the molecule, preferably 0 to 30% by weight, more preferably 5 to 25% by weight of ethylene oxide. Oxide chains may be chipped at molecular ends.

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, THF / 3M-THF copolymer diol And the like. Among these, PTMG, T
HF / EO copolymerized diol and THF / 3M-THF
And copolymerized diols.

The addition of AO to the dihydric alcohol can be carried out by a conventional method, and can be carried out without a catalyst or in the presence of a catalyst (such as an alkali catalyst, an amine-based 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)
The number average (calculated from the OH value) molecular weight of
0 to 5,000, more preferably 700 to 4.5.
00, more preferably 1,000 to 4,000.

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 polyether obtained by ring-opening polymerization of a lactone. It is preferable to include lactone diol, a polycarbonate diol obtained by reacting a dihydric alcohol with a carbonic acid diester of a lower alcohol (such as methanol), and the like.

Examples of the dihydric alcohol include those similar to the dihydric alcohol exemplified as the starting material for the above-mentioned polyalkylene ether diol (b1).

Examples of the polyalkylene ether diol having a molecular weight of 1,000 or less include polytetramethylene ether glycol, polypropylene glycol, polyethylene glycol, and a mixture of two or more thereof.

The dicarboxylic acids include succinic acid,
C2-C12 aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and dodecanoic acid, terephthalic acid, isophthalic acid, and phthalic acid-containing 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.

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 1,000 or less with a dicarboxylic acid or an ester-forming derivative thereof, or an anhydride thereof and AO (for example, EO and / or PO), Alternatively, it can be produced by a method of adding a lactone to an initiator (a low molecular weight diol and / or a polyether diol having a molecular weight of 1,000 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 can be given.

The number average (calculated from the OH value) molecular weight of the polyester diol (b2) is preferably 500 to 5,
000, more preferably 700 to 4,500, and still more preferably 1,000 to 4,000.

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. No. 1,
The ratio between the 2-vinyl structure and the 1,4-trans structure can be variously changed.
0: 0 to 0: 100. The polybutadiene glycol (b3) also includes homopolymers and copolymers (styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, and the like), and hydrogenated products thereof. The hydrogenation rate of the 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 preferably 500 to 5,
000, more preferably 700 to 4,500, and still more preferably 1,000 to 4,000.

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 And ring-containing diols. From the viewpoint of obtaining a high-strength, heat-resistant, light-resistant, high-performance end product with high physical properties, preferred among these are aliphatic glycols, and more preferred are EG,
DEG, 14BG, 3G, and more preferably, EG, 14BG, 3G.

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

In the present invention, one compound having a molecular weight of 200 or less is used.
Examples of the dihydric alcohol (d1) include alkanols such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, and octyl alcohol; for example, cellosolves such as ethyl cellosolve and butyl cellosolve; For example, C1-C1 such as carbitols such as ethyl carbitol and butyl carbitol
10 aliphatic monohydric alcohols, for example, C6-C10 alicyclic monohydric alcohols such as cyclohexanol, for example, tertiary amino group-containing 1 such as N, N-dimethylaminoethanol, N-hydroxyethylmorpholine, etc. Polyhydric alcohols, for example, having 7 to 7 carbon atoms such as benzyl alcohol
And 15 aromatic ring-containing monohydric alcohols, for example, AO (for example, EO and / or PO) adducts of monohydric phenols such as phenol and cresol. Of these, preferred are aliphatic monohydric alcohols, and particularly preferred are alkanols, especially n.
-Propyl alcohol, isopropyl alcohol, n-
Butyl alcohol and isobutyl alcohol.

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,
Examples thereof include aromatic solvents such as xylene and the like, and mixtures of two or more thereof. Among these, preferred are amide solvents, and particularly preferred are DMF and DMAC.

As the reaction terminator used in the present invention, 1
The monohydric alcohol (d2) is the monohydric alcohol (d2) described above.
The same thing as 1) is preferable.

The monoamine (d3) as a reaction terminator used in the present invention includes, for example, ethylamine, n-propylamine, isopropylamine, n-butylamine,
Diethylamine, di-n-propylamine, diisopropylamine, mono- or dialkylamines having 1 to 8 carbon atoms in an alkyl group such as di-n-butylamine, for example, alicyclic monoamines having 6 to 10 carbon atoms such as cyclohexylamine, For example, aniline or the like having 6 to 10 carbon atoms
Aromatic monoamines, for example, monoethanolamine,
C2 of alkanol group such as monoisopropanolamine, diethanolamine and disopropanolamine
And 4 mono- or dialkanolamines, for example, heterocyclic monoamines such as morpholine and the like, and mixtures of two or more thereof. Of these, preferred are dialkylamines.

In the production of the polyurethane resin solution of the present invention, from the viewpoint of easily obtaining a resin having a desired viscosity and molecular weight, improving the viscosity stability of the solution, and improving the strength of the obtained resin. The equivalent ratio of the organic diisocyanate (a) to the active hydrogen group-containing compound comprising the high molecular diol (b), the low molecular diol (c) and the monohydric alcohol (d1) is preferably 0.95: 1 to 0.95: 1.
1.1, more preferably 0.97: 1 to 1.0
5: 1.

The equivalent ratio of the high molecular diol (b) to the low molecular diol (c) is preferably from 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.

In the present invention, the sum of the high molecular diol (b) and the low molecular diol (c) and the monohydric alcohol (d1)
It is important that the equivalent ratio is 1: 0.001 to 1: 0.03.

The ratio of the monohydric alcohol (d1) is 0.00
If it is less than 1, there is a problem that the viscosity stability of the resin solution becomes poor.

If the ratio of the monohydric alcohol (d1) exceeds 0.03, the desired viscosity and molecular weight cannot be obtained, resulting in a problem of poor resin strength.

The equivalent ratio of the sum of the high molecular diol (b) and the low molecular diol (c) to the monohydric alcohol (d1) is preferably from 1: 0.002 to 1: 0.02.

The number average molecular weight (GPC) of the polyurethane resin
Method) is preferably 20,000 from the viewpoint of improving the resin strength and improving the viscosity stability.
~ 200,000, more preferably 40,000
１５０150,000.

The amount of the monohydric alcohol (d2) used as the reaction terminator is determined based on the amount of free NCO groups remaining in the reaction system from the viewpoint of preventing the solution from thickening over time and obtaining good viscosity stability. It is preferably 3 to 50 times equivalent, more preferably 5 to 30 times equivalent.

The content of free NCO groups remaining in the reaction system sealed by the monohydric alcohol (d2) is preferably from 0.01 to 0.1% by weight, based on the solid content of the resin.
More preferably, it is 2 to 0.06% by weight.

When the reaction terminator is a monoamine (d3), the amount used is preferably 1 to 1.5 equivalents, more preferably 1 to 1.1 equivalents, based on the remaining free NCO groups. .

The polyurethane resin solution is prepared by reacting an organic diisocyanate (a), a high molecular diol (b), a low molecular diol (c) and a monohydric alcohol (d1) in the presence of an organic solvent by a one-shot method. At least, the remaining N
When the CO group reaches a specific amount, the NCO group is terminated with a monohydric alcohol (d2) or a monoamine (d3).

The concentration of the resin component in the polyurethane resin solution is adjusted to the target solution viscosity, to prevent the viscosity from increasing over time to prevent the viscosity stability from becoming poor, and to obtain versatility of use, storability, and delivery. Therefore, it is preferably 30 to 50% by weight, more preferably 37 to 45% by weight.

The reaction temperature may be the same as the temperature usually employed for the polyurethane-forming 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 500 ° C. from the viewpoints of variety of uses, storability, delivery properties and viscosity stability.
It is 1,500,000 mPa · s, more preferably 600,000 to 1,300,000 mPa · s.

In order to accelerate the reaction, it is 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.

The polyurethane resin solution obtained by the production method of the present invention may optionally contain a coloring agent such as titanium oxide,
It is preferable to include various stabilizers such as an ultraviolet absorber and an antioxidant, an inorganic filler, an organic modifier, and other additives.

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.

[0062]

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. In the examples, the viscosity, solution viscosity stability, number average molecular weight of the resin, preparation of the film, evaluation of the physical properties of elasticity and elasticity of the film and evaluation of the elastic recovery were performed according to the following methods.

(1) Viscosity The temperature of the sample (polyurethane resin solution) was controlled in a thermostat at 20 ° C. for 5 hours, and then measured with a B-type viscometer [BH-type viscometer manufactured by Toki Sangyo Co., Ltd.].

(2) Solution Viscosity Stability A sample (polyurethane resin solution) was placed in a thermostat at 40 ° C. for 20 minutes.
After storage for a day, the temperature was adjusted to 20 ° C. after storage, 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 a mold release treatment.
It was applied to a thickness of 7 mm, dried for 3 hours with a circulating drier at 70 ° C., and peeled off from the glass plate to form a film having a thickness of about 0.2 mm.

(5) Tensile properties The film to be subjected to the measurement was left 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 is cut into 1 cm × 9 cm, and marked lines are drawn at intervals of 5 cm in the length direction to obtain test samples. Next, the sample was stretched by 300% at a pulling speed of 200 mm / min and held for 2 minutes using an autograph AGS-500D manufactured by Shimadzu Corporation, and then the tension was removed and the elastic recovery rate was measured.

Example 1 A four-necked flask equipped with a stirrer and a thermometer was charged with 230 parts of PTMG having a number average molecular weight (calculated from the OH value) of 2,300 and 14BG having a molecular weight of 90.
21.1 parts, 84.5 parts of MDI, 2.03 parts of n-propyl alcohol and 503 parts of DMAC were charged, reacted at 70 ° C. for 5 hours under a dry nitrogen atmosphere, and then 3.4 parts of n-propyl alcohol was added. [The free NCO content in the reaction system at this time was 0.038% (in terms of resin solid content)] The terminal termination reaction was carried out for 1 hour, and the resin concentration was 40%.
A polyurethane resin solution (A1) having a viscosity of 700,000 mPa · s / 20 ° C. and a number average molecular weight of 65,000 was obtained.
The obtained polyurethane resin solution (A1) was heated at 40 ° C. for 20 minutes.
After storage for days, no particular change in viscosity or turbidity occurred. The polyurethane resin solution is coated on glass, and 7
After drying at 0 ° C. for 3 hours, a film was formed. Table 1 shows the physical properties of the obtained film. The surface had good characteristics without irregularities.

[Example 2] A PT having a number average molecular weight (calculated from the OH value) of 3,100 was placed in the same reaction vessel as in Example 1.
310 parts MG, 16.3 parts EG having a molecular weight of 62, MDI 9
1.5 parts, n-butyl alcohol 5.42 parts and DM
F577 parts were charged and reacted at 70 ° C. for 5 hours in a dry nitrogen atmosphere. Then, 7.0 parts of n-butyl alcohol was added [at this time, the free NCO content in the reaction system was calculated (in terms of resin solid content). 0.048%] for 1 hour, with a resin concentration of 42% and a viscosity of 1,000,000 mP.
A polyurethane resin solution (A2) having a · s / 20 ° C. and a number average molecular weight of 58,000 was obtained. The obtained polyurethane resin solution (A2) 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 in Example 1, a number average (calculated from OH value) TH having a molecular weight of 3,500 was prepared.
350 parts of F / 3M-THF (mol% ratio: 85/15) copolymerized diol, 24.8 parts of EG having a molecular weight of 62, MD
I126 parts, 1.82 parts of n-propyl alcohol and 784 parts of DMAC were charged and dried at 70 ° C. under a dry nitrogen atmosphere.
For 8 hours, then n-propyl alcohol 6.
4 parts were added [at this time, the free NCO content in the reaction system was 0.036% (in terms of resin solid content)], and a 1 hour terminal termination reaction was carried out. The resin concentration was 39%, and the viscosity was 800,00.
A polyurethane resin solution (A3) having 0 mPa · s / 20 ° C. and a number average molecular weight of 63,000 was obtained. The obtained polyurethane resin solution (A3) was stored at 40 ° C. for 20 days.
In particular, no 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 In the same reaction vessel as in Example 1, TH having a number average molecular weight (calculated from the OH value) of 2,900 was used.
290 parts of F / EO (mol% ratio: 90/10) copolymerized diol, 17.7 parts of EG having a molecular weight of 62, MDI 97.
5 parts, 1.73 parts of n-butyl alcohol and DMAC
583 parts were charged and reacted at 70 ° C. for 9 hours in a dry nitrogen atmosphere, and then 3.0 parts of n-butyl alcohol was added. [The free NCO content in the reaction system at this time (in terms of resin solid content) 0.041%] for 1 hour, with a resin concentration of 41% and a viscosity of 900,000 mPa · s.
/ 20 ° C, a polyurethane resin solution (A4) having a number average molecular weight of 56,000 was obtained. The obtained polyurethane resin solution (A4) 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 5] A PT having a number average molecular weight (calculated from the OH value) of 2,300 was placed in the same reaction vessel as in Example 1.
MG 230 parts, 21.1 parts of 14BG having a molecular weight of 90, MD
I8.5 parts, 0.20 parts of n-propyl alcohol and 503 parts of DMAC were charged, and dried under an atmosphere of dry nitrogen.
C. for 5 hours, then di-n-butylamine 0.1.
394 parts were added [the free NCO content in the reaction system at this time was 0.038% (in terms of resin solid content)], and a terminal termination reaction was carried out for 1 hour. The resin concentration was 40% and the viscosity was 710,0.
A polyurethane resin solution (A5) having 00 mPa · s / 20 ° C. and a number average molecular weight of 66,000 was obtained. The obtained polyurethane resin solution (A5) 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.

Comparative Example 1 In a reaction vessel similar to that of Example 1, 230 parts of PTMG having a number average molecular weight of 2,300, 14 parts
BG 21.1 parts, MDI 84.5 parts and DMAC50
3 parts were charged and reacted at 70 ° C. for 5 hours in a dry nitrogen atmosphere, and then 0.4 part of n-propyl alcohol was added. [The free NCO content in the reaction system at this time (in terms of resin solid content) 0.043%] for 1 hour, and a resin concentration of 40% and a viscosity of 720,000 mPa · s /
A polyurethane resin solution (H1) having a number average molecular weight of 65,000 at 20 ° C. was obtained. The obtained polyurethane resin solution (H1) was obtained. The obtained polyurethane resin solution (H
After storing 1) at 40 ° C. for 20 days, an attempt was made to form a film in the same manner as in Example 1. However, since the monohydric alcohol was not initially charged, the viscosity increased and the solution viscosity stability was poor. Fine irregularities were formed on the surface, and a good film could not be obtained.

Comparative Example 2 A PT having a number average (calculated from OH value) molecular weight of 3,100 was placed in the same reaction vessel as in Example 1.
310 parts MG, 16.3 parts EG having a molecular weight of 62, MDI 9
1.5 parts and 577 parts of DMF were charged and reacted at 70 ° C. for 5 hours in a dry nitrogen atmosphere. Then, 13.1 parts of n-butyl alcohol was added [free N in the reaction system at this time].
The CO content was 0.036% (in terms of resin solids). The end termination reaction was carried out for 1 hour, the resin concentration was 42%, the viscosity was 610000 mPa · s / 20 ° C., and the number average molecular weight was 4
8,000 polyurethane resin solutions (H2) were obtained. The obtained polyurethane resin solution (H2) was stored at 40 ° C. for 20 days to form a film. Since no monohydric alcohol was initially charged, the solution viscosity stability was poor, and the resulting film had low strength, low elongation, and low recoverability.

[0076]

[Table 1]

As is clear from Table 1, the polyurethane resin solutions of Examples 1 to 5 of the present invention have remarkably good solution viscosity stability as compared with Comparative Examples 1 and 2, and the obtained films have high elongation properties. Is also at a high level. On the other hand, the polyurethane resin solutions of Comparative Examples 1 and 2 have poor solution viscosity stability and cannot be put to practical use.

[0078]

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.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshio Kobayashi 1 at 11-11 Hitotsubashi-Honcho, Higashiyama-ku, Kyoto-shi, Kyoto Inside Sanyo Chemical Industry Co., Ltd. (72) Inventor Mototaka Inagi 1-1-1, Hitotsubashi-Honcho, Higashiyama-ku, Kyoto-shi, Kyoto Inside Sanyo Chemical Industries Co., Ltd. (72) Inventor Hiroyuki Ogawa 11-11, Hitotsubashi-Honcho, Higashiyama-ku, Kyoto City, Kyoto Prefecture F-term (reference) 4J034 BA08 CA04 CB01 CB03 CC08 DA01 DB04 DB07 DG03 DG05 DG06 DG09 DG10 HA01 HA07 HA11 HC12 HC22 HC46 HC52 HC64 HC71 JA42 KA02 KA04 KD04 KD12 KE02 LB05 QA03 RA09

Claims (8)

[Claims] An organic diisocyanate (a), a high molecular diol (b) having a number average molecular weight of 500 to 5,000, a low molecular diol (c) having a molecular weight of 300 or less, and a molecular weight of 20
When reacting a monohydric alcohol (d1) of 0 or less in an organic solvent, the monohydric alcohol (d1) is reduced to 0 with respect to the total of the high molecular diol (b) and the low molecular diol (c). 0.001 to 0.03 equivalents, and the free isocyanate group content per resin
At the stage when the amount becomes 1 to 0.1% by weight, the monohydric alcohol (d
2. A method for producing a polyurethane resin solution, comprising adding 2). 2. The method for producing a polyurethane resin solution according to claim 1, wherein the monohydric alcohol (d2) is used in an amount equal to or more than three times the equivalent of the isocyanate group. 3. An organic diisocyanate (a), a high molecular diol (b) having a number average molecular weight of 500 to 5,000, a low molecular diol (c) having a molecular weight of 300 or less, and a molecular weight of 20.
When reacting a monohydric alcohol (d1) of 0 or less in an organic solvent, the monohydric alcohol (d1) is reduced to 0 with respect to the total of the high molecular diol (b) and the low molecular diol (c). 0.001 to 0.03 equivalents, and the free isocyanate group content per resin
At the stage when the amount of the monoamine reached 1 to 0.1% by weight, the monoamine (d3)
A method for producing a polyurethane resin solution, comprising: 4. The method for producing a polyurethane resin solution according to claim 3, wherein the monoamine (d3) is used in an amount of 1 to 1.5 equivalents based on the isocyanate group. 5. A polyurethane resin having a number average molecular weight of 20,
The method for producing a polyurethane resin solution according to any one of claims 1 to 4, wherein the concentration is from 000 to 200,000. 6. The method for producing a polyurethane resin solution according to claim 1, wherein the resin content of the solution is 30 to 50% by weight. 7. A solution having a viscosity of 500,000 to 1,500.
The method for producing a polyurethane resin solution according to any one of claims 1 to 6, wherein the temperature is set to 000 mPa · s / 20 ° C. 8. The organic diisocyanate (a) is diphenylmethane diisocyanate, and the polymer diol (b) is polytetramethylene ether glycol, tetrahydrofuran / ethylene oxide copolymerized diol, and tetrahydrofuran-3- The organic solvent is at least one selected from the group consisting of methyltetrahydrofuran copolymerized diol, and the organic solvent is N, N-dimethylformamide and / or N, N-dimethylacetamide. The method for producing a polyurethane resin solution according to any one of claims 1 to 7.