JPH059256A - Method for producing polyurethane - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method for producing polyurethane, which is excellent in flexibility, cold resistance, heat resistance, hydrolysis resistance, and light resistance and is suitable for synthetic leather and artificial leather. [Structure] The number average molecular weight selected from the group consisting of polyester, polycarbonate and polylactone is 400 to 3
000 polymer diol and organic diisocyanate are reacted in a quantitative relationship such that the equivalent ratio of NCO / OH is 0.3 to 0.97, and an intermediate diol having an end OH is obtained,
Diphenylmethane 4,4'-diisocyanate and a low molecular chain extender are reacted.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel method for producing a polyurethane resin. More specifically, by blending the specific components that make up the polyurethane resin in a specific formulation in a specific order and reacting, the various physical properties such as mechanical properties and light resistance are excellent, and it is suitable for synthetic leather and artificial leather. A novel manufacturing method for providing a polyurethane resin

[0002]

2. Description of the Related Art Polyurethane resins obtained by reacting a polymer diol selected from the group consisting of polyester, polycarbonate and polylactone, a low molecular chain extender and an organic diisocyanate are molded products, paints, coating agents, Widely used for adhesives, synthetic / artificial leather, printing ink, etc.

In producing a polyurethane resin, a so-called one-shot method in which necessary raw materials are simultaneously added is often used. However, in the polyurethane resin obtained by this method, the components used in the production are arranged in a statistical distribution according to their reactivity ratios and feed composition ratios. When the heat resistance is poor, or the resin composition with good durability has poor flexibility and cold resistance, or the resin composition with good wet solidification has poor light resistance, the above application characteristics cannot be sufficiently satisfied. Often occur and many proposals for improvement have been made.

A low molecular chain extender and an organic diisocyanate are added to an isocyanate-terminated intermediate diisocyanate obtained by reacting a polymer diol or a mixture of a polymer diol and a low molecular chain extender with a stoichiometric excess of organic diisocyanate. A large number of so-called prepolymer methods have been proposed in which a polyurethane resin is obtained by reacting with. By controlling the arrangement of each component by the prepolymer method,
Although we are seeing a certain improvement effect in improving the application characteristics,
The resulting isocyanate-terminated intermediate diisocyanate is highly reactive and often causes side reactions.
In many cases, the initial purpose cannot be achieved. Not only that, when a diisocyanate of a species whose reactivity is greatly different from that used as the intermediate diisocyanate in the next step is added, there are drawbacks such as difficulty in obtaining a smooth reaction, and there are limitations on the polymerization method. Due to reasons such as the above, the above-mentioned application characteristics often cannot be sufficiently satisfied, and further improvement is desired.

In Japanese Examined Patent Publication No. 38-14048, instead of a hexanediol polyester, each component is a polyester obtained from a glycol having at least 5 carbon atoms and a dicarboxylic acid.
Produced by reacting ~ 0.7 mol, the molecular weight is about 900
It has been shown that the urethane elastomer obtained by the method using a diester urethane in the range of up to 1200 is extremely hard and has insufficient hydrolysis resistance and product elasticity. It is impossible to obtain a polyurethane resin that is suitable for use in bowls, synthetic leather and artificial leather.

Japanese Patent Publication No. 63-4866 discloses a molecular weight of 50.
A high molecular weight diol comprising at least one polyester polyol having a molecular weight of 0 to 5,000 or a polyether polyol having a molecular weight of 600 to 3,000, and a molecular weight of 60 to
A polyol mixed with 250 low molecular weight diols and / or diamines was reacted with 70 to 79 mol% of diphenylmethane-4,4'-diisocyanate to synthesize an active hydrogen-terminated urethane prepolymer, and then 5
Urethane elastomers obtained by reacting with ~ 30 mol% of non-aromatic diisocyanates are disclosed.

The publication shows that the porous film obtained from the polyurethane solution has little discoloration, and asserts its superiority. Further, in this publication, the order of the reaction is changed, and first, a non-aromatic diisocyanate is reacted with a polyol,
Next, it is claimed that the polyurethane elastomer obtained by reacting with diphenylmethane-4,4'-diisocyanate is not preferable because not only discoloration is poor but also wet coagulation property is deteriorated.

However, in the coexistence of the high molecular weight diol and the low molecular weight diol and / or diamine, they are reacted with diphenylmethane-4,4'-diisocyanate all at once, so that the respective components are statistically arranged and non-aromatic in the next step. Although it is reacted with diisocyanate, not only the above-mentioned application characteristics cannot be sufficiently satisfied, but also the effect of improving discoloration is not sufficient, probably because the statistical component arrangement is relieved. In the next step, it is reacted with a non-aromatic diisocyanate, but most of the active hydrogen groups are consumed in the first step, and the active hydrogen group concentration is reduced. The non-aromatic diisocyanate is diphenylmethane-4,4'-
Combined with the fact that the reactivity is significantly inferior to that of diisocyanate, it takes a long time to manufacture and is extremely difficult to carry out industrially.

JP-A-60-161415 discloses a method for producing a polyurethane by reacting an organic polyisocyanate with a polyol, if necessary, in the presence of a foaming agent. In the method, at least a part of the polyol is an organic polyisocyanate (a). ), A polyether polyol (b) having an OH value of 20 to 120, and a primary OH-containing low-molecular diol (c) are used as an OH-terminated urethane prepolymer, and a method for producing a polyurethane is disclosed.

[0010] This publication discloses that O obtained from polyether polyol, low molecular weight diol, and organic polyisocyanate.
It shows that when an OH-terminated prepolymer having an H value of 20 to 50 is used in an amount of 20 to 50% by weight based on the polyol, a polyurethane excellent in curing property and water resistance can be obtained in RIM application, and the superiority is claimed. Further, it is shown that, as an application of the method of the present invention, excellent effects are exhibited in a polyurethane production method that requires a large amount of catalyst and a polyurethane production method using a crosslinking agent.

However, the above-mentioned synthetic leather,
A polyurethane resin having various physical properties suitable for artificial leather can be produced substantially without using a catalyst and without using a cross-linking agent, and cannot be estimated by analogy with the method of the publication. .

Japanese Unexamined Patent Publication (Kokai) No. 2-140217 discloses a method for producing a polyisocyanate component, a polyol component and a polyurethane (A) a compound having an isocyanate group at the terminal obtained from an organic polyisocyanate and a derivative thereof, and (B) one. Polyol having a molecular weight of 500 to 10,000 containing two or more active hydrogen groups in the molecule, (C)
Polyol containing urethane bond, (D) molecular weight 50
A method for producing a polyurethane, which comprises reacting with a chain extender of 0 or less, (E) a polyvalent amine having a molecular weight of 100 to 5000, and (F) a catalyst, a foaming agent, and other additives as required. Is disclosed.

In the publication, it is preferable that the component (C) has a molecular weight of from 500 to 500 to which polyisocyanate, polyether diol, polyether triol, a mixture thereof and a small amount of a tetravalent or higher polyether polyol are added.
2000 polyol and the equivalent ratio of NCO group / active hydrogen group is 0.4 to 0.6, and the polyol containing a urethane bond obtained at a reaction temperature of 60 to 85 ° C. is 1 to 100 parts by weight of the component (B). Bending resistance by using 200 parts by weight,
It has been shown to improve wear resistance and the like, and particularly to exhibit excellent performance when used for shoe soles, and asserts its significance. Although it is described that it is also useful for synthetic leather, automobile parts, furniture, etc., it is shown that it is not useful when polyester polyol is used as the polyol, and when polycarbonate diol, polyester diol, etc. are used, The fact that a polyurethane resin useful for synthetic leather and artificial leather as described above can be obtained by analogy with the method described in the publication.

JP-A-54-127500 discloses a non-yellowing type isocyanate as a polyisocyanate component of a urethane polymer and about 0.05 to 0.85 mol of an aromatic polyisocyanate per mol of the polyisocyanate. Disclosed is a stabilized non-yellowing type urethane polymer characterized by using and.

In this publication, as a preferred embodiment, it is necessary to prevent the aromatic polyisocyanate from reacting only through the chain extender, and the polyfunctional hydroxy compound and the chain extender are first treated to be yellow-free. We show that a polyurethane polymer with good solvent resistance, water resistance, hydrolysis resistance, and yellowing resistance can be obtained when reacted with a modified isocyanate and then with an aromatic polyisocyanate, and its superiority is claimed. ing.

However, in the case of synthetic leather and artificial leather, the aromatic polyisocyanate reacts only through the chain extender, so that it has excellent properties such as strength physical properties and coagulation property, and a polyurethane resin suitable for the intended use is obtained. What is obtained is that the polyurethane resin useful for synthetic leather and artificial leather as described above can be obtained by analogy with the method of the publication.

JP-B-55-19928 discloses a diisocyanate compound having an isocyanate group bonded to an aliphatic hydrocarbon in an amount of 30 to 45 mol% and a molecular weight of 500 to 30.
00 dihydroxy compound of 8 to 15 mol%, low molecular weight dihydroxy compound of 20 to 40 mol%, solution polymerization using a suitable solvent, and further 10 to 20 mol% of aromatic diisocyanate. And a low molecular weight dihydroxy compound in an amount of 10 to 20 mol% to carry out a chain extension reaction.

In the publication, as a preferred embodiment, a dihydroxy compound having a molecular weight of 500 to 3000 and a diisocyanate compound in which a low molecular weight dihydroxy compound is bound to an aliphatic hydrocarbon by an isocyanate group are used as a first step in an NCO / OH equivalent ratio. Of 1 or more are obtained, the aromatic diisocyanate and the low molecular weight dihydroxy compound are added as the second step, and a chain extension reaction is carried out to obtain a polyurethane excellent in dyeability and heat resistance. It shows that it is used for business and claims its superiority.

However, the low molecular weight dihydroxy compound used in the first step is not only inferior in flexibility, probably because it is a chain extender, but also the NCO / OH equivalent ratio is 1 or more, and the residual aliphatic compound remains. Isocyanate group combined with a hydrocarbon group is a reaction rate greatly different compared to the aromatic diisocyanate introduced in the second step, it is difficult to obtain a smooth reaction, industrially synthetic leather as described above, The fact that a polyurethane resin useful for artificial leather can be obtained is an analogy from the method disclosed in this publication.

[0020]

The present invention uses a polymer diol selected from the group consisting of polyesters, polycarbonates and polylactones as a main raw material, and has flexibility, cold resistance, heat resistance and durability suitable for synthetic leather and artificial leather. To produce a polyurethane resin having excellent properties, wet coagulation property, and light resistance.

[0021]

The present invention is a polyester,
Polymer diol (A) and organic diisocyanate (B) selected from the group consisting of polycarbonate and polylactone.
1) and NCO / 0H equivalent ratio of 0.3 to 0.97 in a quantitative relationship such that the intermediate diol (C) of the terminal OH and diphenylmethane 4,4'-diisocyanate ( B2) and a low molecular chain extender (D) are reacted, and a method for producing a polyurethane,
A polymer diol (A) selected from the group consisting of polyester, polycarbonate and polylactone and an aliphatic or alicyclic organic diisocyanate (B1) are used as NCO /
Intermediate diol (C) having terminal OH and diphenylmethane 4,4'-diisocyanate (B2) and low molecular chain obtained by reacting in a quantitative relationship such that an equivalence ratio of 0H is 0.3 to 0.97 A method for producing a polyurethane, which comprises reacting with a stretching agent (D).

The polymer diol (A) is polyester,
It is selected from the group consisting of polycarbonate and polylactone. The number average molecular weight of the degree of polymerization is preferably 400 to 3000, and more preferably 500 to 1500 is selected. If it is less than 400, the flexibility of the polyurethane resin tends to be lost, and if it exceeds 3000, the urethane group concentration inevitably decreases, probably because of the flexibility and cold resistance required for synthetic leather and artificial leather. Not only is it difficult to obtain a polyurethane having a well-balanced heat resistance, durability, and wet coagulation property, but there are also difficulties in industrial production of the polymer-diol.

As the polymer-diol, polyester, polycarbonate and polylactone can be used alone or in a mixture at an arbitrary ratio. Further, there is no limitation to mix low molecular weight diols having a molecular weight of less than 400 so long as the object of the present invention is not impaired, but low molecular weight linear diols such as ethylene glycol, butanediol and hexanediol, xylylene and the like. It is preferable not to substantially include a component usually used as a chain extender such as an aromatic diol such as glycol in terms of flexibility and cold resistance.

The polyester diol used in the present invention can be obtained, for example, by reacting a dibasic acid with a diol. Examples of dibasic acids include aliphatic dibasic acids such as succinic acid, glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid, sebacic acid, and brassic acid, and aromatic dibasic acids such as isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid. It is possible to use one type of basic acid or a combination thereof. Among them, aliphatic dibasic acids, particularly dibasic acids having a methylene chain length of 3 to 8 such as glutaric acid, adipic acid, pimelic acid, speric acid, azelaic acid and sebacic acid are more preferably used. Aliphatic diols such as ethylene glycol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol and dodecanediol, which may be substituted with lower alcohols. Aliphatic diols such as diols, cyclohexanediols and hydrogenated xylyleneglycols, and aromatic diols such as xylyleneglycols are used alone or as a mixture of two or more thereof. Among them, aliphatic diols are
In particular, one or a mixture of two or more aliphatic diols having a carbon chain length of 4 to 9 such as butanediol, methylpentanediol, hexanediol, heptanediol, methyloctanediol and nonanediol is preferably used.

The polycarbonate diol can be obtained, for example, by reacting a carbonate compound with a diol. As the carbonate compound, dimethyl carbonate, diphenyl carbonate, ethylene carbonate and the like can be used. As the diol, ethylene glycol optionally substituted with a lower alcohol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol,
Aliphatic diols such as heptane diol, octane diol, nonane diol, decane diol and dodecane diol, alicyclic diols such as cyclohexane diol and hydrogenated xylylene glycol, and aromatic diols such as xylylene glycol and one or two. Mixtures of two or more species are used, among which aliphatic diols, especially butanediol, methylpentanediol, hexanediol, heptanediol, methyloctanediol, nonanediol, and other aliphatic diols having a carbon chain length of 4 to 9 are used. One kind or a mixture of two or more kinds is preferably used.

Polylactone diols are, for example, poly-
ε-caprolactone diol, poly-trimethyl-ε-
Examples thereof include caprolactone diol and poly-β-methyl-δ-valerolactone diol.

The organic diisocyanate (B1) is, for example, diphenylmethane-4,4'-diisocyanate,
Aromatic diisocyanates such as 2,4- or 2,6-tolylene diisocyanate, meta or paraphenylene diisocyanate, 1,5 naphthylene diisocyanate, isophorone diisocyanate, cyclohexane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, hydrogenated MDI, etc. A non-aromatic diisocyanate is used. Among them, as the organic diisocyanate (B1) capable of reacting with the polymer diol (A), asymmetric diisocyanates such as 2,4- or 2,6-tolylene diisocyanate and isophorone diisocyanate, and among them, isophorone diisocyanate is soft and is used for synthetic leather and artificial leather. Is more preferable because isophorone diisocyanate is more preferable because synthetic polyurethane having good flexibility and light resistance and polyurethane suitable for artificial leather can be obtained.

The terminal OH intermediate diol (C) reacts with the polymer diol (A) and the organic diisocyanate (B1) in a quantitative relationship such that the equivalent ratio of NCO / OH is 0.3 to 0.97. Obtained. If the equivalent ratio of NCO / OH is less than 0.3, the molecular weight of the polymer diol (A),
Depending on the type of organic diisocyanate (B1), the balance of flexibility, cold resistance, and heat resistance may be due to the fact that the amount of urethane bonds incorporated into the intermediate diol at the terminal OH is too small or the molecular weight is too small. It is difficult to obtain, and the effects of the present invention cannot be sufficiently obtained. Also NCO
If the equivalent ratio of / 0H exceeds 0.97, the amount will vary depending on the molecular weight of the polymer diol (A) and the type of organic diisocyanate (B1), but the amount of urethane bonds incorporated into the intermediate diol at the terminal OH is too large, Further, it is difficult to balance the flexibility, cold resistance, and heat resistance, probably because the molecular weight becomes too large, and the effect of the present invention cannot be sufficiently obtained.

As the chain extender (D), ethylene glycol optionally substituted with lower alcohol, propylene glycol, butanediol, neopentyl glycol, methylpentanediol, hexanediol, heptanediol, octanediol, nonanediol, decane. Aliphatic diols such as diol and dodecanediol, alicyclic diols such as cyclohexanediol and hydrogenated xylyleneglycol, aromatic diols such as xylyleneglycol, and one or a mixture of two or more such as diethylene glycol are used. Among them, aliphatic diols, especially ethylene glycol,
Butanediol is preferably used in terms of the balance of flexibility, cold resistance, heat resistance, wet coagulation and the like.

The amount of the low molecular chain extender (D) to be used is not particularly limited, but it usually varies depending on its molecular structure, the molecular weight of the polymer diol (A), the type of organic diisocyanate, and the NCO / OH equivalent ratio. For the polymer diol (A), the equivalent ratio of (D) / (A) is 0.5 to 5
Among them, polyurethane obtained from 1 to 3 is often suitable in terms of flexibility, cold resistance, heat resistance, and wet coagulation property.

The amount of diphenylmethane-4,4'-diisocyanate (B2) used is not particularly limited, and the viscosity of the polyurethane solution, the molecular weight of the polymer diol (A), the polymer diol (A) and the organic diisocyanate (B1).
NCO / OH equivalent ratio of, the reaction solvent, the polymer diol (A), the water contained in the low molecular chain extender (D), etc., but usually N from (B1) and (B2)
CO, polymer diol (A) and low molecular chain extender (D)
Equivalent ratio NCO / OH of hydroxyl groups from 0.95 to 1.2
Especially, it is often used at 0.97 to 1.1.

In the production method of the present invention, a catalyst is not always necessary, but catalysts used in the usual production of polyurethane, for example, metal compounds such as titanium tetraisopropoxide, dibutyltin dilaurate and tin octate, and tetramethylbutanediamine. A tertiary amine such as 1,4-diaza (2,2,2) bicyclooctane can be used.

As the solvent for the polyurethane obtained by the method of the present invention, for example, commonly used solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, toluene, ethyl acetate, methyl ethyl ketone, tetrahydrofuran and the like are used.

The polyurethane obtained by the method of the present invention is
Before use, it is possible to add various additives used in conventional polyurethane, such as flame retardants such as phosphorus compounds and halogen-containing compounds, antioxidants, ultraviolet absorbers, pigments, dyes, plasticizers, and surfactants. it can.

[0035]

The polyurethane of the present invention thus obtained is used as a sheet, film, belt, hose, anti-vibration material, shoe sole, artificial leather, synthetic leather, fiber treatment agent, paint, adhesive, waterproof material, elastic fiber. Although it is useful for various purposes such as flooring, it is excellent in flexibility, heat resistance, cold resistance, coagulation property, light resistance and the like, and is particularly useful for artificial leather and synthetic leather.

Although its mechanism of action is not clear, a terminal containing a urethane group obtained under the condition that the polymer diol (A) and the organic diisocyanate (B1) have a specific composition ratio and substantially no chain extender coexists. OH intermediate diol (C) in the presence of a chain extender (D) diphenylmethane-
A chain extender (D) which is considered to form a hard segment component with a OH intermediate diol (C) containing a urethane group which is considered to form a soft segment component by reacting with 4,4′-diisocyanate (B2). ) And diphenylmethane-4,4'-diisocyanate (B2) are in an appropriate microphase-separated state.

[0037]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

Examples 1 to 6 and Comparative Examples 1 to 7 (Production of Intermediates) Examples 1 to 7 and Comparative Examples 4 and 7 are
The polymer diol and diisocyanate shown in Table 1 were charged into a reactor and reacted under a nitrogen stream at the temperature and time shown in Table 1 to obtain an intermediate (C). After confirming that the isocyanate group was lost, the weight average molecular weight (in terms of polystyrene) of the intermediate (C) was measured by GPC, and the results are also shown in Table 1.

[0039]

[Table 1]

The abbreviations in the table are: PNOA: a mixture of nonanediol and 2-methyloctanediol in a ratio of 65:35 (weight ratio) and adipic acid. Polyester diol having a number average molecular weight of 1000: PHC: number average molecular weight of 1000 Polyhexylene carbonate MDI: diphenylmethane-4,4'-diisocyanate TDI: tolylene diisocyanate (80/20 mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate) ) IPDI: isophorone diisocyanate EG: ethylene glycol DMF: N, N'-dimethylformamide.

(Production of Polyurethane) The intermediate or polymer diol obtained above was charged with diisocyanate having the composition shown in Table 2, ethylene glycol, and DMF as a solvent in a reactor, and the temperature and time shown in Table 2 under a nitrogen stream. The reaction was carried out, and the reaction mixture was cooled when no isocyanate group was observed. In addition, in Comparative Examples 3 and 4, 1 at 80 ° C.
After the reaction was continued for 2 hours, the isocyanate group remained, and the solution viscosity was extremely low. Therefore, 2 parts by weight of dibutyltin dilaurate was added as a polymerization catalyst, and 8
The reaction was continued at 0 ° C. for 14 to 16 hours and cooled when the isocyanate group disappeared to obtain a polyurethane solution.
The viscosity (poise) of the obtained polyurethane solution at 30 ° C. and the weight average molecular weight (converted to polystyrene) measured by GPC are shown in Table 2.

[0042]

[Table 2]

(Evaluation) The physical properties of a film having a thickness of 60 μ obtained by casting and drying these solutions by the following evaluation methods are shown in Table 3. -Flexibility (100% modulus): Using Shimadzu Autograph AG-100A, sample width 0.5 cm, chuck interval 4 cm, head speed 200 mm / min, ambient temperature 20
Measured at ℃ and 65% relative humidity. -Cold resistance (Tα): Rheovibron DDV-II-EP manufactured by Orientec Co., Ltd., sample width 0.4 cm, sample length 2.
Peak temperature of loss modulus of complex modulus measured at 5 cm, heating rate of 3 ° C./min, and frequency of 11 hertz. -Heat resistance (Tf): sample width 0.4 cm, sample length 2.5 cm,
The temperature when the sample was stretched by 0.5 cm at a heating rate of 3 ° C / min and a load of 2 g.・ Hydrolysis resistance (strength retention rate): 70 ° C, relative humidity 95
% Retention of sample breaking strength after 5 weeks exposure. For breaking strength, an autograph AG-100A manufactured by Shimadzu Corporation was used.
Sample width 0.5 cm, chuck spacing 4 cm, head speed 2
Measured at 00 mm / min, ambient temperature 20 ° C, relative humidity 65%. -Light yellowing resistance: Shimadzu Fade Tester CF-20S was used to perform carbon arc irradiation at 63 ° C, and a gray scale for discoloration / fading for JIS dyeing fastness test was used to see the time when the color difference of No. 4 was observed and the series It was judged. No.4 color difference in 20 hours No.4 color difference in 40 hours No.5 color difference No.4 in 60 hours No.6 color difference

[0044]

[Table 3]

Despite having the same composition in Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, and Example 3 and Comparative Example 3, (A) and (B1) were replaced with NCO / OH. The intermediates (C) and (D) and (B2) obtained by reacting in a quantitative relationship such that the equivalent ratio of Flexible (100% low modulus), cold resistance (low Tα), good heat resistance (high Tf) polyurethane is obtained, while (B1) and (B2) are obtained without passing through the intermediate (C). All of the conventional methods of reacting all at once have extremely poor cold resistance and heat resistance, and react (B1) and (B2) all at once to obtain a polyurethane resin without passing through the intermediate (C). The effect of the present invention is clear as compared with the known method.

In Comparative Example 2, the flexibility was good, but the cold resistance and heat resistance were extremely poor, and (B1) and (B2) were reacted together without passing through the intermediate (C). In this case, the effect of using the asymmetric diisocyanate is not obtained as in Example 2, and the effect of the present invention is clear as compared with the known method of reacting all at once to obtain a polyurethane resin.

In Example 3, since isophorone diisocyanate was used for the production of the intermediate (C), it was excellent in light yellowing resistance, good in hydrolysis resistance, flexible (100% small modulus) and cold resistance (low Tα), A polyurethane having good heat resistance (high Tf) was obtained, but Comparative Example 3 had cold resistance,
Not only the heat resistance is extremely poor, but also the hydrolysis resistance and the light yellowing resistance are poor, and isophorone diisocyanate is used as (B1) in the present invention which reacts intermediates (C) with (D) and (B2). The advantages of the invention used are clear.

Comparative Example 4 has an NCO / OH equivalent ratio of 1.1.
It is a reaction product of (D) and (B2) with an intermediate obtained by reacting in a quantitative relationship such as 7. However, not only cold resistance and heat resistance are extremely poor, but also water resistance is high. The degradability was poor. That is, the effect of the present invention in which the equivalent ratio of NCO / OH of (A) and (B1) in the production of the intermediate is 0.97 or less is obvious.

The compositions of Example 4 and Comparative Example 6 were the same,
Comparative Example 5 is different in diisocyanate, but Example 4 is
A polyurethane having good hydrolysis resistance, flexibility (100% modulus is small) and heat resistance (high Tf) was obtained, and Comparative Examples 5 and 6 were inferior in flexibility (particularly 1 of Example 5).
00% modulus is large), cold resistance is poor, and heat resistance is poor. (A) and (B1) have an NCO / OH equivalent ratio of 0.7.
Intermediate (C) obtained by reacting in a quantitative relationship such that
The effect of the present invention of reacting (D) and (B2) with each other and the effect of using an asymmetric diisocyanate for the production of the intermediate are obvious.

In Examples 5 and 6 and Comparative Example 7, (A) and (B1) in the production of the intermediate were changed so that the equivalent ratio of NCO / OH was decreased, but the equivalent ratio was 0. In Examples 5 and 6 of 5 or 0.35, a polyurethane having good hydrolysis resistance, softness (small 100% modulus) and cold resistance (low Tα), good heat resistance (high Tf), Intermediates (C), (D) and (B2) obtained by reacting (A) and (B1) in a quantitative relationship such that the equivalent ratio of NCO / OH is 0.5 or 0.35 are obtained. The effect of the present invention of reacting is clear. On the other hand, Comparative Example 7 having an equivalence ratio of 0.1 has poor flexibility and poor cold resistance,
When (D) and (B2) are reacted with an intermediate obtained by reacting (A) and (B1) in a quantitative relationship such that the heat resistance is poor and the equivalent ratio of NCO / OH is 0.1. The effect of the present invention was not clearly obtained.

In addition, considering in Comparative Example 4 that the NCO / OH equivalent ratio is 1.17, the effect of the present invention was not obtained at all.
The effect of the method of obtaining a polyurethane resin through the intermediate (C) obtained by reacting 1) with an NCO / OH equivalent ratio of 0.3 to 0.97 is clear.

[0052]

As described above, the polyurethane obtained by the method of the present invention has flexibility, heat resistance, cold resistance, coagulability, and
It has excellent light resistance and hydrolysis resistance, and is particularly useful for artificial leather and synthetic leather.

Claims (2)

[Claims] 1. A polymer diol (A) selected from the group consisting of polyesters, polycarbonates and polylactones and an organic diisocyanate (B1) are NCO / 0.
(C), diphenylmethane 4,4′-diisocyanate (B2), and a low molecular weight compound, which are obtained by reacting in a quantitative relationship such that the equivalent ratio of H is 0.3 to 0.97. A method for producing a polyurethane, which comprises reacting with a chain extender (D). 2. A polymer diol (A) selected from the group consisting of polyester, polycarbonate and polylactone and an aliphatic or alicyclic organic diisocyanate (B1) at an NCO / OH equivalent ratio of 0.3 to 0.97.
It is characterized by reacting the terminal OH intermediate diol (C), diphenylmethane 4,4′-diisocyanate (B2) and low molecular chain extender (D) obtained by reacting in a quantitative relationship such that And a method for producing a polyurethane.