JP2764431B2 - Polyurethane and its manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyurethane having good elasticity and a method for producing the same.

In particular, the polyurethanes of the present invention have high elongation at break,
A polyurethane with good elasticity, showing small stress fluctuations due to deformation strain during elongation, small hysteresis loss of stress during elongation, small residual strain after elongation under cryogenic conditions, and excellent dyeability. is there.

Further, the polyurethane of the present invention can exhibit these various properties and can be widely used for foams, elastomers, paints, fibers, adhesives, flooring materials, sealants, medical materials, artificial leathers, and the like.

(Prior Art) In recent years, polyurethanes have been used in a wide variety of fields, and further improvements in various elastic functions are desired.

That is, as the elastic function at room temperature, high elongation at break,
It is desired that the stress fluctuation with respect to the deformation strain is small, and that the hysteresis loss of the stress at the time of expansion and contraction is small.

Attempts to suppress the crystallinity of the soft segment in polyurethane using various low-melting diols for the purpose of improving these elastic functions have been actively made, but the above-mentioned elastic functions are still insufficient. It has not yet reached a level that is satisfactory.

For example, a polyurethane using a copolymerized ether ester diol as a low melting point diol component (Japanese Patent Application Laid-Open No.
JP-A-55-160016 and JP-A-58-59213) have poor durability such as hydrolysis resistance and mold resistance due to the presence of an ester bond group in the diol component. Limited.

Also, a diol obtained by adding ethylene oxide or propylene oxide to polytetramethylene glycol (hereinafter, PTMG) having an ether bonding group as a diol component, or a copolymerized polyalkylene ether of tetrahydrofuran (hereinafter, THF) and the above-mentioned alkylene oxide Polyurethanes using diols and the like have a drawback that durability such as water resistance and light resistance is significantly reduced as compared with polyurethanes using only PTMG.

Further, examples of polyurethanes using a polyalkylene ether diol copolymerized with THF and a low molecular weight cyclic ether compound, i.e., JP-A-58-125718, JP-A-60-1985.
No. 26021, JP-A-63-235320, JP-A-61-120
No. 830 has also been proposed, but its elastic function is far inferior to the polyurethane according to the invention.

Also, JP-A-61-120830, U.S. Pat.
No. 5 describes the use of copolymer type polyether polyols, polyurethanes, polyesters, and polyamides as soft segments. In addition, JP
JP-120830 describes a polyether glycol in which neopentyl glycol groups are copolymerized at 4.2 mol%, and U.S. Pat. No. 4,658,065 describes a polyurethane using 3.4 mol% copolymerized polyether glycol, respectively. However, there is no disclosure of polyurethanes which have a low copolymerization ratio and, when molded into fibers or films, have remarkably improved elastic functions such as high elongation, stress fluctuation, hysteresis loss and residual strain.

SUMMARY OF THE INVENTION The present invention provides excellent elasticity functions, namely, high elongation at break, small stress fluctuation with respect to strain during elongation, and stress during expansion and contraction, without causing the above problems in the prior art. The present invention provides a polyurethane having a small hysteresis loss, a small residual strain after expansion and contraction under cryogenic conditions, excellent dyeing properties, and excellent elasticity, and a process for producing the same.

(Means for Solving the Problems) As a result of intensive studies to solve the problems, the present inventors have found that a specific polyalkylene having a specific number of methyl groups in a specific side chain of a specific alkylene group. It has been found that when ether diol is used, a polyurethane having excellent elasticity can be obtained, and the present invention has been achieved.

That is, the present invention provides: (1) (i) an organic polyisocyanate compound, which comprises a structural unit represented by the following structural formula (A) and structural formulas (B) and / or (C); _{formula: 0.08 ≦ (M B + M} C) / (M a + M B + M C) having a composition satisfying the ≦ 0.85, polyalkylene ether diol having a molecular weight of 300 to 30,000, (where, M _X is, X = a, B and C are the total number of the structural units X present in the polyalkylene ether diol, and the structural units (A), (B) and / or (C) are in random form in the polyalkylene ether diol. or may be present in either _{block-like.) CH 2 4 O- ··· (} a) And (ii) the total of the hydroxyl group of the polyalkylene ether diol and the active hydrogen group of the active hydrogen-containing compound is 1.01 equivalent to the isocyanate group of the organic polyisocyanate compound. Provide a polyurethane that is less than. Moreover, the range of (2) the _{(M B + M C) /} (M A + M B + M C) 0.10~
Another characteristic is that it is 0.45. (3) The following structural formula (A), structural formula (B) and / or
Or made of a structural unit represented by structural formula (C), and the following _{equation: 0.08 ≦ (M B + M} C) / having a composition satisfying the _{(M A + M B + M} C) ≦ 0.85, molecular weight 300 to 30,000 a polyalkylene ether diol, (where, M _X is, X = a, B, in C, and the total number of structural units X present in the polyalkylene ether diol, and (a) (B) and / or structural units (C) is present in the polyalkylene ether diol may be present in either a random form or block _{form.) CH 2 4 O- ··· (} a) An organic polyisocyanate compound, and an active hydrogen-containing compound that reacts with an isocyanate group, the total of the hydroxyl group of the polyalkylene ether diol and the active hydrogen group of the active hydrogen-containing compound is 1.01 equivalent to the isocyanate group of the organic polyisocyanate compound. A process for producing a polyurethane. Moreover, the range of (4) above _{(M B + M C) /} (M A + M B + M C) 0.10~
Another characteristic is that it is 0.45.

 Hereinafter, the present invention will be described in detail.

The polyurethane of the present invention is an organic polyisocyanate; R ₁ NCO) _X (R ₁ is an organic residue, and x is an integer of 2 or more)
...... (i) polyalkylene ether _{diol: HO-R 2 -OH (R} 2 is the residue of Po real ether diol of the present invention.) ...... (ii) an active hydrogen-containing compound: H-R ₃ - H and / or R ₄ —H (R ₃ and R ₄ are the residues of an active hydrogen-containing compound.)... (Iii) (Where L and N are integers of 1 or more) having a structure represented by repetition of the structural units (iv) and (v), and the structural unit (iv):
According to the number of functional groups of the organic polyisocyanate compound constituting the skeleton of (v), the urethane-bonded portion or the urea-bonded portion bonded to the R ₁ group may be increased or decreased. The terminal is -R _3-
H or may be -R _4.

Polyalkylene ether diol used in the present invention,
The need to include segments 8 mol% or more and 85 mol% or less with a defined side-chain methyl groups in the formula (I), i.e., the _{0.08 ≦ (M B + M C} ) / (M A + M B + M _C ) ≦ 0.85
It is necessary to have the relationship

In the above case, when the segment having a methyl group in the side chain contains less than 8 mol% or more than 85 mol%, various elastic functions of the obtained polyurethane polymer such as elongation at break and cryogenic properties are obtained. Decrease. Preferably comprises 10 mol% to 45 mol%, i.e., in the range of _{(M B + M C) /} (M A + M B + M C) 0.10~0.45
Is more desirable.

This particular polyalkylene ether diol comprises tetrahydrofuran and the low molecular weight diol,
Neopentyl glycol, 3-methyl-1,5-pentanediol, or a dehydrated cyclic low molecular weight compound thereof, for example,
It is produced by reacting 3,3-dimethyloxetane with a heteropolyacid having a controlled hydration number as a catalyst in accordance with the method described in JP-A-61-123628. The copolymerized diol can be easily produced by variously changing the reaction method and conditions so as to have a predetermined molecular weight, a copolymer component constitution and a copolymerization ratio.

The neopentyl unit or 3-methyl-1,5-pentylene unit constituting the diol may be distributed in a random or block manner with respect to the tetramethylene unit. The diol can be distributed in any shape or random, and the crystallinity of the diol can be changed in various ways effectively, and a diol having each crystallinity can be produced according to the characteristics of the polyurethane.

Further, the number average molecular weight of the polyalkylene ether diol used in the present invention is 300 to 30,000, preferably 500
Between 5,000 and even more preferred is between 1,000 and 4,000.

Further, the polyalkylene ether diol represented by claim 1 used in the present invention is converted into another diol having a number average molecular weight of about 250 to 20,000, for example, polyoxyethylene glycol, polyoxypropylene glycol, polyoxytetramethylene glycol. , Polyoxypentamethylene glycol, polyoxypropylene tetramethylene glycol and other polyether diols; one or more dibasic acids such as adipic acid, sebacic acid, maleic acid, itaconic acid, azelaic acid, malonic acid and ethylene Glycol, 1,2-propylene glycol,
1,3-propylene glycol, 2,2-dimethyl-1,3-
Glycols such as propanediol, 1,4-butanediol, 2,3-butanediol, hexamethylene glycol, diethylene glycol, 1,10-decanediol, 1,3-cyclohexanedimethanol, and 1,4-cyclohexanedimethanol; Polyester diols such as polyester diols and poly-ε-caprolactone, polyvalerolactone, and the like obtained from at least one kind thereof, polyester amide diols, polyether-ester diols,
It may be used in combination with polycarbonate diol or the like at an arbitrary ratio or in combination.

In the present invention, the polyalkylene ether diol represented by claim 1 and the organic polyisocyanate compound according to claim 1, that is, a compound having at least two or more isocyanate groups in a molecule, for example, 2,4- Tolylene diisocyanate, 2,6-tolylene diisocyanate (TDI), 4,
4'-diphenylmethane diisocyanate (MDI), xylene diisocyanate, isophorone diisocyanate,
p-Phenylene diisocyanate, bis (3-methyl-
4. An active hydrogen-containing compound that reacts with an isocyanate group according to claim 1, such as (a) water, or (b) 4-isocyanatophenyl) methane, bis (4-isocyanatocyclohexyl) methane, hexamethylene diisocyanate, or the like. ) Ethylenediamine, propylenediamine, trimethylenediamine, hexamethylenediamine, hydrazine, carbodihydrazide, adipate dihydrazide, sebacate dihydrazide, N, N'-bis (γ-aminopropyl) -N, N-
Difunctional aliphatic diamines such as dimethylethylenediamine, or (c) monofunctional amino compounds such as monofunctional secondary amines, ie, dimethylamine, methylethylamine, diethylamine, methyl-n-propylamine, methyl-isopropylamine , Diisopropylamine, methyl-n-butylamine, methyl-isobutylamine, methylisoamylamine, or (d) diols such as ethylene glycol, propylene glycol, butylene glycol, and (e) used in the present invention. A polyalkylene ether diol having the indicated structure and (f) a known number average molecular weight of 250 to
Polyurethane can be produced by reacting in the presence of about 5,000 diols and (g) monohydric alcohols.

The organic polyisocyanate and the active hydrogen-containing compound used in the present invention may be used alone, or may be used by mixing them as needed.

For the operation of the polyurethane conversion reaction, a known polyurethane conversion reaction technique is used. For example, a polyalkylene ether diol and an organic polyisocyanate are reacted under an excess of an organic polyisocyanate compound at a ratio of 1: 1 to 1: 3.0, preferably 1: 1.3 to 1: 2.0 (equivalent ratio), and urethane is reacted. After synthesizing the prepolymer, an active hydrogen-containing compound that reacts with the isocyanate group can be added to the isocyanate group in the prepolymer and allowed to react, or an organic polyisocyanate compound, a polyalkylene ether diol, The reaction can also be performed by a one-shot polymerization method in which the hydrogen-containing compounds are simultaneously reacted in one step.

Regarding the operation of the polyurethane reaction, a solvent such as dimethylformamide, dimethylsulfoxide, dimethylacetamide, benzene, and toluene may be used as necessary.

The stoichiometric ratio of the various compounds used in the present invention is such that the sum of the hydroxyl groups of the polyalkylene ether diol having the structure represented by claim 1 and the active hydrogen of the active hydrogen-containing compound is an organic polyisocyanate. It is less than 1.01 equivalent to isocyanate groups of the compound.

Further, the polyurethane of the present invention, if desired, a gas yellowing inhibitor, a light stabilizer, an ultraviolet absorber, an antioxidant, calcium stearate, magnesium stearate, polytetrafluoroethylene, an anti-adhesive such as an organopolysiloxane, Inorganic fine particles such as titanium oxide, zinc oxide, and magnesium oxide, and other compounding agents can be appropriately compounded.

Hereinafter, the present invention will be described with reference to examples, but these do not limit the scope of the present invention.

(Example) The number average molecular weight, structure (composition ratio, terminal group analysis), melting point, and physical properties of the polyurethane in Examples and Comparative Examples were measured by the following method and apparatus. .

Hydroxyl (OH) value: Determined by the pyridine-phthalic anhydride method, from which the number average molecular weight was determined.

Composition ratio and terminal group analysis: Determined by ¹ H. ¹³ C-NMR (JEOL-GX 400 manufactured by JEOL Ltd.).

Melting point: DSC (SSC580 / DSC-20 manufactured by Seiko Instruments Inc.)
Asked by.

Infrared spectrum: Determined by (Perkin Elmer FT-IR-1640).

Measurement of physical properties of polyurethane: Measured at 20 ° C. (Tensilon RTM-100 manufactured by Orientec Co., Ltd.). However,
The temperature of 0 ° C. and −20 ° C. used a constant temperature bath model TLF-III-1-40B-S for a tensile tester manufactured by Orientec Co., Ltd.

Reference Example 1 (Production example of polyalkylene ether diol) A container equipped with a stirrer and a reflux condenser is charged with 500 g of tetrahydrofuran and 68 g of neopentyl glycol. Three
Add 500 g of anhydrous phosphotungstic acid by heating at 40 ° C. for 3 hours and keeping at 60 ° C. in a dry nitrogen gas atmosphere.
After reacting with stirring for 10 hours, the mixture is allowed to stand at room temperature to separate into two phases. The upper layer was separated, and unreacted tetrahydrofuran and neopentyl glycol were removed by distillation to obtain 145 g of a transparent and viscous polyalkylene ether diol.

This product OH number, DSC measured by NMR measurement, the number average molecular weight of 2,000, with freezing point -20 ° C., the formula (I) is the _{(M B + M C) /} (M A + M B + M C) = 0.19 I understood that.

The infrared spectrum and ¹ H-NMR spectrum of this polyalkylene ether diol are shown in FIGS.

Reference Example 2 (Example of producing polyalkylene ether diol using dehydrated cyclic low molecular weight compound) A container equipped with a stirrer and a reflux condenser is charged with 500 g of tetrahydrofuran and 1.56 g of water. Add 250 g of anhydrous phosphotungstic acid by heating at 340 ° C. for 3 hours. Under an atmosphere of dry nitrogen gas, while maintaining at 60 ° C., 90 g of 3,3-dimethyloxetane was added dropwise at a rate of 0.75 g / min with stirring.
The reaction is carried out with stirring for 6 hours while maintaining the temperature at 0 ° C. When left at room temperature, it separates into two phases, and the unreacted TH
The F, 3,3-dimethyloxetane was removed to obtain 153 g of a transparent and viscous polyalkylene ether diol.

This product OH number, DSC measured by NMR measurement, the number average molecular weight of 2,000, of the formula (I) was found to be _{(M B + M C) /} (M A + M B + M C) = 0.32.

Example 1 2,000 g (1 mol) of the polyalkylene ether diol having a number average molecular weight of 2,000 of Reference Example 1 and 400 g (1.6 mol) of 4,4′-diphenylmethane diisocyanate (hereinafter abbreviated as MDI) were placed in a drying chamber. The reaction was carried out at 80 ° C. for 3 hours under stirring to obtain a prepolymer. After cooling to room temperature, 4,457 g of dimethylacetamide was added and dissolved with stirring at room temperature to obtain a uniform prepolymer solution.

On the other hand, 34.2 g (0.57 mol) of ethylenediamine and 4.38 g (0.06 mol) of diethylamine were added to dimethylacetamide 1,2
The solution dissolved in 33 g was added to the above prepolymer solution at a stretch under high speed stirring, and further reacted at room temperature for 1 hour to obtain a polyurethane. Cast this solution on a glass plate,
After drying at 60 ° C. for 24 hours, a dried film having a thickness of 100 μm was prepared and subjected to various physical property tests. Table 2 shows the physical properties.

Also, from this solution, 40d of polyurethane fiber was obtained by ordinary dry spinning. Table 3 shows the physical properties.

(Example 2) Using the polyalkylene ether diol of Reference Example 2,
In the same manner as in Example 1, the polyurethane solution, the dried film, and
After obtaining the polyurethane fiber of d, it was subjected to various physical property tests.

The physical properties of the dried film and the polyurethane fiber are shown in Tables 2 and 3, respectively.

(Examples 3 to 5) According to Reference Example 2, polyalkylene ether diols were produced at the composition molar ratios of the diols described in Examples 3 to 5 in Table 1 below. After obtaining a polyurethane solution, a dry film, and a 40d polyurethane fiber in the same manner as in Example 1 with the composition and reaction ratio of each example described in the above section, each was subjected to various physical property tests.

The physical properties of the dried film and the polyurethane fiber are shown in Tables 2 and 3, respectively.

(Example 6) According to Reference Example 1, instead of neopentyl glycol, 3-methyl-1,5-pentanediol was used to convert the molecular weight of 1,950 and 3-methyl-1,5-pentylene unit to the above (I). expression, to produce a polyalkylene ether diol comprising a _{(M B + M C) /} (M a + M B + M C) = 0.25. Using such a polyalkylene ether diol, a polyurethane solution, a dry film, and a 40d polyurethane fiber were obtained in the same manner as in Example 1 at the compositions and reaction ratios of the examples described in Table 1, and then various types were obtained. It was subjected to a physical property test.

The physical properties of the dried film and the polyurethane fiber are shown in Tables 2 and 3, respectively.

(Comparative Examples 1 to 3) According to Reference Example 2, polyalkylene ether diols were produced with the molar composition of the diols described in Comparative Examples 1 to 3 in Table 1 below, and the compositions described in Table 1 were obtained. After obtaining a polyurethane solution, a dried film, and a polyurethane fiber of 40d in the same manner as in Example 1 at a reaction ratio, they were subjected to various physical property tests.

The physical properties of the dried film and the polyurethane fiber are shown in Tables 2 and 3, respectively.

(Comparative Examples 4 and 5) According to Example 1 described in JP-A-60-26021,
Polyalkylene ether diols described in Comparative Examples 4 and 5 in Table 1 below were produced, and the polyalkylene ether diols were used to obtain the compositions and reaction ratios described in Comparative Examples 4 and 5 in Table 1 below. After obtaining a polyurethane solution, a dried film, and a 40d polyurethane fiber in the same manner as in Example 1, they were subjected to various physical property tests.

The physical properties of the dried film and the polyurethane fiber are shown in Tables 2 and 3, respectively.

(Comparative Example 6) According to Example 2 described in JP-A-63-235320,
A polyalkylene ether diol described in Comparative Example 6 in Table 1 below was produced, and this polyalkylene ether diol was used to obtain a composition and a reaction ratio described in Comparative Example 6 in Table 1 below. Similarly, after obtaining a polyurethane solution, a dry film, and a 40d polyurethane fiber, they were subjected to various physical property tests.

The physical properties of the dried film and the polyurethane fiber are shown in Tables 2 and 3, respectively.

In Table 1, * 1: The structural units in the table indicate combinations of ether structural units in the polyalkylene ether diol.

(In addition, in Comparative Examples 1 and 5, a polyalkylene ether diol consisting of a single diol unit was used. In Comparative Examples 4 and 6, () indicates 2-methyl-propylene relative to all structural units. Units and the ratio of 3-methyl-tetramethylene units are shown.) In Table 2, * 2: Breaking strength and breaking elongation when a tensile test was performed at 20 ° C. on a 5 cm long sample at a strain rate of 1,000% / min.

* 3: When the elongation and recovery up to 300% is repeated three times at a strain rate of 1,000% / minute at temperatures of 0 ° C and -20 ° C, the stress at the third recovery becomes zero in Fig. 3. Shows the residual strain.

* 4: In Fig. 3, when the elongation and recovery up to 300% at a strain rate of 1,000% / min were repeated three times at 20 ° C, the elongation with respect to the stress at the time of recovery at the third 200% strain It shows the retention of stress.

* 5: The ratio of the stress at 600% in FIG. 4 to the stress at 100% when the tensile test was performed at 20 ° C. and a strain rate of 1,000% / min.

FIG. 3 showing the relationship between the residual strain and the stress retention, which was created based on the experimental values shown in Tables 2 and 3,
In detail, a sample of 5 cm in length is used with tensilon for 1,000
It shows the third SS curve when the elongation and recovery up to 300% is repeated at a strain rate of% / min, and the strain when the stress at the time of recovery becomes 0 is the residual strain (%).
The ratio of the stress at the time of recovery at the time of 200% to the stress at the time of elongation: That is, stress retention = f _R / f _S × 100 (%).

In Table 3: * 6: All values in the table are measured in the same manner as in Table 2.

* 7: However, only the breaking strength is the value per denier before strain is applied.

Similarly, FIG. 4 showing the stress fluctuation rate, which is created based on the experimental values shown in Tables 2 and 3,
FIG. 4 shows an SS curve when a sample having a sample length of 5 cm was stretched with a tensilon at a strain rate of 1000% / min until breaking, and is represented by a stress fluctuation rate = f ₂ / f ₁ (times). .

(Effect of the Invention) The polyurethane in the present invention is particularly useful as a fiber and a film.

That is, especially when used as a fiber, it has a high elongation, so that the working draft (covering draft) can be increased, which is economical, and furthermore, the yarn breakage in the warping process and the knitting process. Very few times.

In addition, since the initial stress at the time of initial elongation (100%) is higher than the conventional ester diol urethane elastic yarn,
There is little sticking of the yarn during aging and handling is easy.

Furthermore, it has an excellent elasticity function such that stress fluctuation during middle to high-stage elongation (100% to 600%) is small and hysteresis loss during expansion and contraction is small.

Further, when formed into a film or fiber, it exhibits excellent properties of elasticity and small residual strain, which are not seen in conventional polyurethane, under extremely low temperature conditions (-20 ° C or lower).

The polyurethane of the present invention has a lower hydrophilicity than a polyurethane made from a copolymer diol having excellent low-temperature properties comprising conventionally known THF and ethylene oxide or propylene oxide or 8-methyl THF. I have.

Furthermore, it was also found that the polyurethane of the present invention has improved dyeability since the mobility of the amorphous portion is increased.

[Brief description of the drawings]

FIG. 1 shows an infrared spectrum of the synthesized polyalkylene ether diol of Reference Example 1. FIG. 2 shows a ¹ H-NMR spectrum of the polyalkylene ether diol synthesized in Reference Example 1. FIG. 3 is a graph showing the relationship between the residual strain and the stress retention of the dry film and the fiber obtained according to the example (comparative example). FIG. 4 is a graph showing the stress fluctuation rate of the dry film and the fiber.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-235320 (JP, A) JP-A-60-135421 (JP, A) JP-A-60-26021 (JP, A) JP-A Sho 54- 163997 (JP, A) JP-A-61-123628 (JP, A) JP-A-61-120830 (JP, A) JP-A-58-125718 (JP, A) (58) Fields investigated (Int. ⁶ , DB name) C08G 18/48

Claims (4)

(57) [Claims] (I) An organic polyisocyanate compound, comprising a structural unit represented by the following structural formula (A) and structural formulas (B) and / or (C), and having the following formula: 0.08 ≦ _A polyalkylene ether diol having a composition satisfying (M _B + M _C ) / (M _A + M _B + M _C ) ≦ 0.85 and having a molecular weight of 300 to 30,000 (where M _X is X = A, B, C , The total number of structural units X present in the polyalkylene ether diol, wherein the structural units (A), (B) and / or (C) are in random or block form in the polyalkylene ether diol. both in may also be _{present.) CH 2 4 O- ··· (} A) And (ii) the total of the hydroxyl group of the polyalkylene ether diol and the active hydrogen group of the active hydrogen-containing compound is 1.01 equivalent to the isocyanate group of the organic polyisocyanate compound. Polyurethane. 2. The range of (M _B + M _C ) / (M _A + M _B + M _C )
The polyurethane according to claim 1, wherein the polyurethane is 0.10 to 0.45. 3. The following structural formula (A) and structural formula (B)
And / or a structural unit represented by the structural formula (C),
And the formula: 0.08 ≦ with _{(M B + M C) /} (M A + M B + M C) composition which satisfies ≦ 0.85, and polyalkylene ether diol having a molecular weight of 300 to 30,000, (where, M _X is, X = A, B, C, the total number of structural units X present in the polyalkylene ether diol, wherein the structural units (A), (B) and / or (C) are to, may be present in either a random form or block _{form.) CH 2 4 O- ··· (} a) An organic polyisocyanate compound, and an active hydrogen-containing compound that reacts with an isocyanate group, the total of the hydroxyl group of the polyalkylene ether diol and the active hydrogen group of the active hydrogen-containing compound is 1.01 equivalent to the isocyanate group of the organic polyisocyanate compound A method for producing a polyurethane, characterized in that the reaction is carried out in less than or equal to. 4. The range of (M _B + M _C ) / (M _A + M _B + M _C )
4. The process for producing a polyurethane according to claim 3, wherein the ratio is 0.10 to 0.45.