JP2653710B2 - Polyurethane, production method thereof, and polyester diol used therefor - Google Patents

Description

The present invention relates to a novel polyurethane, a method for producing the same, and a polyester diol used as a raw material of the polyurethane.

The polyurethane provided by the present invention has excellent heat resistance and injection moldability, and is also excellent in water resistance, cold resistance and mechanical performance, and thus is useful as a material for various molded articles.

[Conventional technology]

Conventionally, polyurethane has a high elastic modulus, and has many features such as excellent abrasion resistance and oil resistance, so it has been attracting attention as an alternative material to rubber and plastic,
It has been increasingly used in a wide range of applications as a molding material to which ordinary plastic molding methods can be applied. Polyurethane is produced by mixing and polymerizing a chain extender such as a polymer diol, diisocyanate and 1,4-butanediol. It is known that in order to produce a homogeneous polyurethane, it is preferable to mix and polymerize the raw materials in a molten state.

As polyurethane, polyester-based polyurethane,
Polyether-based polyurethane, polycarbonate-based polyurethane, and the like are known, and these polyurethanes are used for various purposes according to their characteristics.
For example, polyether-based polyurethane is used for applications where hydrolysis resistance is particularly required, polyester-based polyurethane is used for applications where mechanical performance, oil resistance and abrasion resistance are particularly required, and polycarbonate-based polyurethane is used for polyester-based polyurethane. It is used for applications that require durability in addition to its features.

Among polyester-based polyurethanes, poly (butylene adipate) -based polyurethanes are relatively inexpensive and generally have relatively good properties.
Poly (hexamethylene adipate) -based polyurethane and the like are widely used. However, these general-purpose polyester-based polyurethanes have poor heat resistance, have a long cycle time of injection molding, are inferior in productivity, have problems in injection moldability such as generation of sink marks, and have water resistance and cold resistance. Because of poor properties, it is often impossible to satisfy the performance required in terms of use or product. Accordingly, there is a strong need for these improvements.

As polyester-based polyurethanes having improved water resistance and cold resistance, 1,9-nonanediol and 3-methyl-
Polyester polyol obtained by reacting a specific diol having a side chain of a methyl group such as 1,5-pentanediol, 2-methyl-1,3-propanediol, neopentyl glycol and a dicarboxylic acid with a polymer diol Polyester-based polyurethane (see JP-A-61-185520) and 2-methyl-1,8-
Polyester polyurethane produced by using octanediol or a mixture thereof with a linear alkylene glycol having 6 to 9 carbon atoms with a dicarboxylic acid as a polymer polyol (Japanese Patent Application Laid-Open No. 62-22817). Reference) has been proposed. Japanese Patent Application Laid-Open No. 61-185520 discloses that, in the production of polyester polyol, if the amount is 5% by weight or less based on a mixture of 1,9-nonanediol and a diol having a methyl group side chain. It is stated that ethylene glycol, propylene glycol or 1,4-butanediol may be used. Further, the above-mentioned JP-A-62-2281
No. 7 discloses that a straight chain alkylene glycol having 6 to 9 carbon atoms is replaced with a diol having 5 or less carbon atoms in 2-methyl-1,
It is described that hydrolysis resistance and low-temperature flexibility of polyester-based polyurethane produced using a polyester polyol obtained by reacting a dicarboxylic acid with 8-octanediol are greatly reduced.

[Problems to be solved by the invention]

JP-A-61-185520 and JP-A-62-222817.
The inventors of the present invention have studied that two types of polyester polyurethanes having improved water resistance and cold resistance as proposed in Japanese Patent Application Laid-Open Publication No. H10-133, respectively, may also improve the injection moldability. However, it was found that the improvement in heat resistance was not always sufficient.

One object of the present invention is to provide a high-performance polyester-based polyurethane having excellent heat resistance and injection moldability, and also excellent water resistance, cold resistance and mechanical performance.

Another object of the present invention is to provide a method for producing the above-mentioned high-performance polyester-based polyurethane.

Still another object of the present invention is to provide a polyester diol which provides the above-mentioned high-performance polyester-based polyurethane.

[Means for solving the problem]

According to the present invention, one of the above-mentioned objects is that the main chain is composed of a polyester diol unit and the following structural unit (VII), and the polyester diol unit has the following structural units (I) and (II) And one or three structural units selected from (III) and the following structural units (IV) and (V)
Wherein the sum of the molar fractions of the structural units (I), (II), (III) and (IV) is equal to the molar fraction of the structural unit (V), and the structural units (I) and (II) The sum of the mole fractions is 10% or more of the sum of the mole fractions of the structural units (I), (II), (III) and (IV), and the structural units (II) and (III)
Is at least 10% of the sum of the molar fractions of the structural units (I), (II), (III) and (IV), and the molar fraction of the structural unit (IV) is Structural units (I), (I
30% based on the sum of the mole fractions of I), (III) and (IV)
The above is achieved by providing a polyurethane having a logarithmic viscosity of 0.3 to 2.0 dl / g.

(I): —OCH ₂ ) _m —O— (wherein, m represents an integer of 8 to 10.) (III): - O-R 1 -O- (IV) ( wherein, R ¹ represents a primary glycol residue having 4 to 8 carbon atoms having a side chain.): - OCH _{2 4} -O- (In the formula, n represents an integer of 4 to 8.) (Wherein, R ² represents a divalent saturated aliphatic hydrocarbon group, a saturated alicyclic hydrocarbon group or an aromatic hydrocarbon group.) Another object of the present invention is to provide a structural unit (I), ( Consisting of one to three types of structural units selected from II) and (III) and structural units (IV) and (V), the moles of the structural units (I), (II), (III) and (IV) The sum of the fractions is equal to the molar fraction of the structural unit (V), and the structural unit (I)
And the sum of the molar fractions of (II) is the structural unit (I), (II),
10% or more with respect to the sum of the mole fractions of (III) and (IV), and the sum of the mole fractions of the structural units (II) and (III) corresponds to the structural units (I), (II) and (III) ) And (IV) is at least 10% with respect to the sum of the mole fractions, and the mole fraction of the structural unit (IV) is
Is a chain extension of a polyester diol having a number average molecular weight of 600 to 5,000 and a diisocyanate in which at least 30% of the molecular terminals have the following structural unit (VI) with respect to the sum of the mole fractions of This is attained by providing a method for producing the above polyurethane, which is characterized by performing melt polymerization in the presence or absence of an agent.

_{(VI): - OCH 2 4} OH Still another object of the above is by connexion achieved to provide a polyester diol of the above.

The above structural units (I), (II), (III), (IV),
(V), (VI) and (VII) will be described in detail below.

The structural unit (I) is derived from 1,8-octanediol, 1,9-nonanediol or 1,10-decanediol. In view of the heat resistance of polyurethane, the structural unit (I) is
It is preferably a unit derived from 1,9-nonanediol or 1,10-decanediol. In addition, from the viewpoint of giving polyurethane excellent in both heat resistance and cold resistance,
Most preferred are units derived from 9-nonanediol.

The structural unit (II) is derived from 2-methyl-1,8-octanediol.

4 carbon atoms having a side chain represented by R ¹ in the structural unit (III)
The primary glycol residue having a carbon number of 4 to 8 is
2 of the form in which two hydroxyl groups have been removed from the primary glycol
Is a monovalent hydrocarbon group. In this specification,
“Primary glycol” means a glycol having two hydroxymethyl groups in a molecule. The structural unit (III) is derived from a primary glycol having 4 to 8 carbon atoms having a side chain, and the side chain is preferably an alkyl group having 1 to 3 carbon atoms. Examples of the primary glycol include 3-methyl-1,5-pentanediol, neopentyl glycol, 2-methyl-1,3-propanediol, and 4-methyl-1,7-heptanediol. In view of the heat resistance of the polyurethane, the structural unit (III) is derived from a primary glycol having 6 to 8 carbon atoms having a side chain such as 3-methyl-1,5-pentanediol and 4-methyl-1,7-heptanediol. It is preferably a derived unit.

Structural unit having side chain (II) and structural unit (III)
By adjusting the molar fraction of the polyurethane, cold resistance, flexibility and elastic recovery can be imparted to the polyurethane.

The structural unit (IV) is derived from 1,4-butanediol. When the structural unit (IV) is replaced with a unit derived from an alkanediol other than 1,4-butanediol such as ethylene glycol and 1,5-pentanediol, the resulting polyurethane has poor heat resistance and moldability. The high-performance polyurethane aimed at by the present invention cannot be obtained because it is insufficient, and furthermore, the cold resistance and the water resistance are sometimes insufficient.

Structural unit (I) constituting the polyurethane of the present invention,
(II), (III) and (IV) are structural units (I) and (I)
The sum of the mole fractions of (I) is the structural unit (I), (II), (III)
And 10% or more, preferably 15% or more, based on the sum of the mole fractions of the structural units (II) and (III). , (III) and (I
V) is at least 10% with respect to the sum of the mole fractions, and the mole fraction of the structural unit (IV) is
The relationship must be 30% or more, preferably 30 to 80%, more preferably 30 to 75% with respect to the sum of the mole fractions of I) and (IV). Structural units (I), (II), (III)
If (IV) and (IV) do not satisfy this relationship, the high-performance polyurethane intended in the present invention cannot be obtained.

The structural unit (V) is derived from a linear saturated aliphatic dicarboxylic acid having 6 to 10 carbon atoms. Examples of the dicarboxylic acid include adipic acid, pimelic acid, speric acid, azelaic acid and sebacic acid. In view of the heat resistance of the polyurethane, the structural unit (V) is preferably a unit derived from adipic acid or azelaic acid. The molar fraction of the structural unit (V) is determined by the structural units (I), (II),
Equal to the sum of the mole fractions of (III) and (IV).

The structural unit (VI) is derived from 1,4-butanediol. R ² in the structural unit (VI) is a divalent saturated aliphatic hydrocarbon group such as a hexamethylene group; a divalent saturated alicyclic group such as an isophoronediyl group or a dicyclohexylmethane-4,4′-diyl group. A hydrocarbon group; or a divalent aromatic hydrocarbon group such as diphenylmethane-4,4'-diyl group, p-phenylene group, methylphenylene group, 1,5-naphthylene group, xylene-α, α'-diyl group. Represent. Structural units (VII) has the general formula ^{O = C = N-R 2} -N = C = O ( wherein, R ² is as defined above.) Represented by the two isocyanate groups in the molecule It is derived from the aliphatic, cycloaliphatic or aromatic diisocyanates it contains. As the diisocyanate, for example, 4,4 '
-Diphenylmethane diisocyanate, p-phenylene diisocyanate, tolylene diisocyanate, 1,5-
Aromatic diisocyanates such as naphthylene diisocyanate; aliphatic diisocyanates such as xylylene diisocyanate and hexamethylene diisocyanate; and alicyclic diisocyanates such as isophorone diisocyanate and 4,4'-dicyclohexylmethane diisocyanate.

As described above, the main chain of the polyurethane of the present invention contains a specific polyester diol unit and a structural unit (VII), and in addition to these units, a small amount of a structural unit derived from a chain extender as described later. It may be contained. The content of the structural unit derived from such a chain extender is usually 20% by weight or less based on the polyurethane. For the purpose of obtaining a polyurethane having a particularly good thermoplasticity or a polyurethane particularly suitable as a material for synthetic leather, artificial leather, elastic fiber, etc., the polyurethane has a structural unit derived from a chain extender in an amount of 5 to 10% by weight based on the polyurethane. %.

As described above, the polyurethane of the present invention is produced by melt-polymerizing a specific polyester diol and a diisocyanate giving the structural unit (VII) in the presence or absence of a chain extender. As the polymerization conditions, those known in the art for the urethane formation reaction are applied, and the polymerization temperature is preferably in the range of 200 to 240 ° C. By maintaining the polymerization temperature at 200 ° C. or higher, a polyurethane having good moldability can be obtained. By maintaining the polymerization temperature at 240 ° C. or lower, a polyurethane having increased heat resistance can be obtained. As the polymerization method, it is particularly preferable to employ a continuous melt polymerization method using a multi-screw extruder.

As the chain extender, a chain growing agent commonly used in polyurethane production, that is, a low molecular weight compound having a molecular weight of 400 or less containing at least two hydrogen atoms capable of reacting with isocyanate in a molecule can be used. Glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanediol, 1,4-bis (β-hydroxyethoxy) benzene And diols such as bis (β-hydroxyethyl) terephthalate and xylylene glycol; diamines such as ethylenediamine, propylenediamine, xylylenediamine, isophoronediamine, piperazine, phenylenediamine and tolylenediamine; hydrazine;
Examples include dihydrazides such as adipic dihydrazide and isophthalic dihydrazide. As a chain extender
Most preferably, 1,4-butanediol or 1,4-bis (β-hydroxyethoxy) benzene is used. These compounds are used alone or in combination of two or more.

The polyester diol used as a raw material of the polyurethane of the present invention comprises one or three structural units selected from the structural units (I), (II) and (III) described above, and structural units (IV) and (V). And at least 30% of the molecular terminals have the structural unit (VI). Structural unit (V
When a polyester diol having a content of I) of less than 30% of the molecular terminal is used, it is difficult to obtain a polyurethane having good heat resistance. The polyester diol is selected from the structural units (I), (II) and (III).
One or more diols that provide from three to three structural units;
Known amounts of polyethylene terephthalate, polybutylene terephthalate, and the like can be obtained from predetermined amounts of 1,4-butanediol that provides structural units (IV) and (VI) and linear saturated aliphatic dicarboxylic acid or its ester that provides structural unit (V). It is produced by performing a known transesterification reaction or direct esterification reaction followed by a melt polycondensation reaction employed in the production of the polyester. As a raw material of the polyurethane of the present invention, a polyester diol having a number average molecular weight in the range of 600 to 5,000 determined from a hydroxyl value and an acid value is used. When the number average molecular weight of the polyester diol is less than 600, the obtained polyurethane has poor low-temperature properties, and when it is more than 5,000, the resulting polyurethane has poor mechanical performance. From the viewpoint of low-temperature properties and mechanical performance of the obtained polyurethane, polyester diols having a number average molecular weight in the range of 800 to 4,000 are preferable.

The polyurethane obtained as described above has a concentration of 0.5 g
It has a logarithmic viscosity of 0.3-2.0 dl / g determined at 30 ° C. as a 100/100 ml dimethylformamide solution. Polyurethane having a logarithmic viscosity of 0.5 to 1.5 dl / g is preferred.

The polyurethane of the present invention is particularly excellent in molding processability such as injection moldability and heat resistance, and therefore can be easily molded by a commonly used injection molding machine, extrusion molding machine, blow molding machine or the like. Since the polyurethane of the present invention has excellent heat resistance, water resistance, cold resistance and mechanical performance, sheets, films, rolls, gears, solid tires, belts, hoses, tubes, packing materials, vibration insulators, shoe soles, It is used as a material for sports shoes and other laminated products, mechanical parts, automobile parts, sports equipment, elastic fibers, etc. Further, the polyurethane of the present invention is dissolved in a solvent and used for artificial leather, a fiber treatment agent, an adhesive, a binder, a paint, and the like. Further, the polyurethane of the present invention is a known filler, stabilizer, coloring agent, depending on the purpose,
A reinforcing agent or the like can be mixed and used.

〔Example〕

Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, the measurement of the number average molecular weight of the polyester diol, the identification and quantification of the terminal structure, and the measurement of the logarithmic viscosity of the polyurethane were carried out according to the following methods. The heat resistance, injection moldability, water resistance, cold resistance and mechanical performance of the polyurethane were evaluated according to the following methods. The "hard content" of a polyurethane refers to the weight percentage of segments based on diisocyanate and chain extender in the polyurethane.

(1) Number average molecular weight: determined from the hydroxyl value and acid value of the polyester diol.

(2) Identification and quantification of terminal structure: The terminal structure of polyester diol was identified and quantified using 500 MHz proton NMR [JNM-GX500, manufactured by JEOL Ltd.].

(3) Logarithmic viscosity: Polyurethane was dissolved in dimethylformamide and measured at 30 ° C. at a concentration of 0.5 g / 100 ml.

(4) Heat resistance: The vicat softening temperature (° C) was determined according to the method specified in JIS K7206, and the heat resistance was evaluated. That is, the vicat softening temperature is 1.00 to 1.05 kgf
The temperature at which a needle-shaped indenter having a flat tip and a round cross-sectional area of 1 mm ² penetrates into a test piece by 1 mm while applying a load of 1 and increasing the temperature at a rate of 50 ± 5 ° C./hour.

(5) Injection moldability: The injection moldability was evaluated based on the cycleability of injection molding and the occurrence of sink marks. Regarding cycleability, cycle time (sum of injection time and cooling time)
+++ for 50 seconds or less, +++ for 60-80 seconds
Those with seconds or more are indicated by +. Regarding the occurrence of sink marks, +++++ indicates the absence of sink marks, ++ indicates the occurrence of slight sink marks, + indicates the significant sink marks, and +++ indicates the intermediate state between +++ and ++.

(6) Water resistance: 100 μm thick polyurethane film
The film was subjected to a jangle test in which the film was left standing at 70 ° C. and a relative humidity of 95% for 28 days. The tensile strength of the film before and after the test was compared, and the retention of the film was determined.

(7) Cold resistance: A test piece prepared from a polyurethane film having a thickness of 100 μm was measured using a dynamic viscoelasticity measuring device (DVE Rheospectral, manufactured by Rheology Co., Ltd.).
While increasing the temperature of the test piece at a frequency of 11 Hz, the temperature Tα at which the dynamic loss elastic modulus E ″ reaches a peak was measured, and thereby the cold resistance was evaluated.

(8) Mechanical performance: Evaluated according to the method specified in JIS K7311. That is, a dumbbell-shaped test piece made of a polyurethane film having a thickness of 100 μm (parallel portion width: 5 m
m; length of parallel part: 20 mm), and the breaking strength and the breaking elongation were measured at a tensile speed of 30 cm / min, and the mechanical performance was evaluated based on these.

Example 1 Preparation of Polyester Diol A mixture of 2-methyl-1,8-octanediol, 1,9-nonanediol and 1,4-butanediol (molar ratio = 1)
7:33:50) 1,600 g and adipic acid 1,460 g (molar ratio of diol to adipic acid = 1.3: 1.0) were charged to the reactor,
The esterification reaction was carried out under normal pressure while passing nitrogen gas through the system and distilling off water produced at about 220 ° C. out of the system. When the acid value of the polyester became 0.3 or less, the degree of vacuum was gradually increased by a vacuum pump to complete the reaction. The polyester diol thus obtained has a hydroxyl value of 56,
It had an acid number of 0.20 and a number average molecular weight of 2,000, and the terminal 48% was derived from 1,4-butanediol.

Examples 2 to 12 and Comparative Examples 1 to 12 Production of polyester diol The same procedures as in Example 1 except that the desired amounts of dicarboxylic acid to give the dicarboxylic acid component shown in Table 1 and diol to give the diol component shown in Table 2 were used, respectively. To carry out an esterification reaction to obtain corresponding polyester diols. The reaction time was appropriately changed in accordance with the desired molecular weight of the polyester diol.

With respect to the polyester diols obtained in Examples 1 to 12 and Comparative Examples 1 to 12, the dicarboxylic acid components and their ratios are shown in Table 1, the diol components and their ratios are shown in Table 2, and the number average molecular weight and the structural units at all terminals ( Table 3 shows the percentage of VI). In Tables 1 and 2, the dicarboxylic acid component and the diol component are indicated using the following abbreviations, respectively.

AD: adipic acid AZA: azelaic acid SBA: sebacic acid DA: 1,10-decanedicarboxylic acid OD: 1,8-octanediol ND: 1,9-nonanediol DD: 1,10-decanediol MOD: 2-methyl -1,8-octanediol MPD: 3-methyl-1,5-pentanediol MPG: 2-methyl-1,3-propanediol BD: 1,4-butanediol HD: 1,6-hexanediol PD: 1 , 5-pentanediol EG: ethylene glycol Example 13 Production and Performance Evaluation of Polyurethane A mixture of a polyester diol (A) and 1,4-butanediol (hereinafter abbreviated as BD) at a molar ratio of 1: 4 was heated to 30 ° C. and 50 ° C. 4, heated and melted
4'-diphenylmethane diisocyanate (hereinafter abbreviated as MDI) is rotated in the same direction by a metering pump in such an amount that the molar ratio of polyester diol (A) to MDI to BD is 1: 5: 4. A continuous melt polymerization reaction was carried out by continuously charging the twin-screw extruder.
When the inside of the twin-screw extruder was divided into three zones, a front portion, an intermediate portion and a rear portion, the highest temperature (polymerization temperature) of the intermediate portion was set to 220 ° C. The resulting polyurethane was continuously extruded into water in the form of a strand, and then formed into a pellet with a pelletizer. Further, the pellet was formed by hot pressing to obtain a sheet and a film, which were evaluated for heat resistance, water resistance, cold resistance and mechanical performance. The injection moldability was also evaluated using a pellet. Tables 5 and 6 show the evaluation results.

The obtained polyurethane had good heat resistance, injection moldability, water resistance, cold resistance and mechanical performance.

Examples 14 to 23 and Comparative Examples 13 to 22 Production and Performance Evaluation of Polyurethane In Example 13, the polyester diol shown in Table 4 was used in place of the polyester diol (A).
Polyester diol, MDI and BD were prepared in the same molar ratio except that the reaction and subsequent operations were performed in the same manner to obtain a polyurethane pellet, which was similarly molded into sheets and films, and various performances were evaluated. . Tables 5 and 6 show the evaluation results.

The polyurethanes obtained in the examples had good heat resistance, injection moldability, water resistance, cold resistance and mechanical performance.

In the polyurethane obtained by the comparative example, heat resistance,
There was no good polyurethane in all of the injection moldability, water resistance, cold resistance and mechanical performance.

Example 24 Production and Performance Evaluation of Polyurethane In Example 13, polyester diol (A), MD
The reaction and subsequent operations were carried out in the same manner except that I and BD were charged in such amounts that their molar ratio was 1: 5.5: 4.5 to obtain a pellet of polyurethane, which was similarly formed into sheets and films. And various performances were evaluated. The hard content of the resulting polyurethane was 47%. Tables 5 and 6 show the evaluation results.

The obtained polyurethane was good in all of heat resistance, injection moldability, water resistance, cold resistance and mechanical performance.

Comparative Example 23 Production and Performance Evaluation of Polyurethane In Example 13, polyester diol (S) was used in place of polyester diol (A), and polyester diol (S) was used so that the obtained polyurethane had a hard content of 47%. MDI and BD in a molar ratio of 1: 1.6 to 0.
The reaction and subsequent operations were performed in the same manner except for the preparation in step 6, to obtain a polyurethane pellet, which was similarly formed into a sheet and a film, and various performances were evaluated. Tables 5 and 6 show the evaluation results.

The obtained polyurethane had poor heat resistance, injection moldability and cold resistance.

Comparative Example 24 Production and Evaluation of Polyurethane In Example 13, polyester diol (T) was used in place of polyester diol (A), and polyester diol (T) was used so that the obtained polyurethane had a hard content of 32%. MDI and BD in a molar ratio of 1: 7.8 to 6.
The reaction and subsequent operations were carried out in the same manner except for charging in step 8 to obtain a polyurethane pellet, which was similarly formed into a sheet and a film, and various performances were evaluated. Tables 5 and 6 show the evaluation results.

The obtained polyurethane had poor heat resistance, water resistance and mechanical performance.

Example 25 Production of Polyurethane and Evaluation of Performance In Example 13, polyester diol (U) was used in place of polyester diol (A), and the molar ratio of polyester diol (U), MDI and BD was 1: 6.5 to 6.5. The reaction and subsequent operations were carried out in the same manner except that the mixture was charged in an amount of 5.5 to obtain a polyurethane pellet, which was similarly formed into a sheet and a film, and various performances were evaluated. The hard content of the obtained polyurethane was 42%. Table 5 and Table 6 show the evaluation results.
Shown in

The obtained polyurethane was good in all of heat resistance, injection moldability, water resistance, cold resistance and mechanical performance.

Example 26 Production and Performance Evaluation of Polyurethane In Example 13, BD was replaced with 1,1 as a chain extender instead of BD.
The reaction and subsequent operations were performed in the same manner except that a mixture of 4-bis (β-hydroxyethoxy) benzene having a molar ratio of 2: 1 was used to obtain a pellet of polyurethane, which was similarly formed into sheets and films. Then, various performances were evaluated. Tables 5 and 6 show the evaluation results.

The obtained polyurethane was good in all of heat resistance, injection moldability, water resistance, cold resistance and mechanical performance.

[Effects of the Invention] Polyurethane provided by the present invention, as is apparent from the above examples, heat resistance, injection moldability, water resistance,
Excellent in all aspects of cold resistance and mechanical performance. The polyurethane is also excellent in oil resistance and bending resistance. According to the present invention, there is provided a method for producing a polyurethane having such excellent performance, and a polyester diol which provides the polyurethane.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-156820 (JP, A) JP-A-63-182330 (JP, A) JP-A-63-182387 (JP, A) JP-A-62 39613 (JP, A) JP-A-63-202610 (JP, A) JP-A-62-22817 (JP, A) JP-A-61-185520 (JP, A) JP-A-2-20514 (JP, A) JP-A-2-41379 (JP, A) WO 88/5447 (WO, A1)

Claims (4)

(57) [Claims] (1) a main chain comprising a polyester diol unit and the following structural unit (VII), wherein the polyester diol unit comprises the following structural units (I), (II) and (II):
It comprises one to three kinds of structural units selected from I) and the following structural units (IV) and (V), and the mole fraction of the structural units (I), (II), (III) and (IV) Is equal to the mole fraction of the structural unit (V), and the structural unit (I)
And the sum of the molar fractions of (II) is the structural unit (I), (II),
10% or more with respect to the sum of the mole fractions of (III) and (IV), and the sum of the mole fractions of the structural units (II) and (III) corresponds to the structural units (I), (II) and (III) ) And (IV) are at least 10% based on the sum of the mole fractions, and the mole fraction of the structural unit (IV) is at least one of the structural units (I), (II), (III) and (I).
Logarithmic viscosity of 30% or more based on the sum of the mole fractions of V)
0.3-2.0dl / g polyurethane. (I): - O- (CH 2) m -O- ( wherein, m represents an integer of 8-10.) (III): —O—R ¹ —O— (wherein, R ¹ represents a primary glycol residue having 4 to 8 carbon atoms having a side chain.) (IV): —O— (CH ₂ ) ₄ — O- (In the formula, n represents an integer of 4 to 8.) (In the formula, R ² represents a divalent saturated aliphatic hydrocarbon group, a saturated alicyclic hydrocarbon group or an aromatic hydrocarbon group.) 2. The polyurethane according to claim 1, wherein the main chain comprises the polyester diol unit, the structural unit (VII) and a structural unit derived from a chain extender. 3. The following structural units (I), (II) and (II)
It comprises one to three kinds of structural units selected from I) and the following structural units (IV) and (V), and the mole fraction of the structural units (I), (II), (III) and (IV) Is equal to the mole fraction of the structural unit (V), and the structural unit (I)
And the sum of the molar fractions of (II) is the structural unit (I), (II),
10% or more with respect to the sum of the mole fractions of (III) and (IV), and the sum of the mole fractions of the structural units (II) and (III) corresponds to the structural units (I), (II) and (III) ) And (IV) is at least 10% based on the sum of the mole fractions, and the mole fraction of the structural unit (IV) is at least one of the structural units (I), (II), (III) and (IV).
Is a chain extension of a polyester diol having a number average molecular weight of 600 to 5,000 and a diisocyanate in which at least 30% of the molecular terminals have the following structural unit (VI) with respect to the sum of the mole fractions of 3. The method for producing a polyurethane according to claim 2, wherein melt polymerization is carried out in the presence of an agent. (I): - O- (CH 2) m -O- ( wherein, m represents an integer of 8-10.) (III): —O—R ¹ —O— (wherein, R ¹ represents a primary glycol residue having 4 to 8 carbon atoms having a side chain.) (IV): —O— (CH ₂ ) ₄ — O- (In the formula, n represents an integer of 4 to 8.) (VI): —O— (CH ₂ ) ₄ —OH 4. The following structural units (I), (II) and (II)
It comprises one to three kinds of structural units selected from I) and the following structural units (IV) and (V), and the mole fraction of the structural units (I), (II), (III) and (IV) Is equal to the mole fraction of the structural unit (V), and the structural unit (I)
And the sum of the molar fractions of (II) is the structural unit (I), (II),
10% or more with respect to the sum of the mole fractions of (III) and (IV), and the sum of the mole fractions of the structural units (II) and (III) corresponds to the structural units (I), (II) and (III) ) And (IV) is at least 10% with respect to the sum of the mole fractions, and the mole fraction of the structural unit (IV) is
A polyester diol for producing polyurethane having a number average molecular weight of 600 to 5,000, in which at least 30% of the molecular terminals have the following structural unit (VI) based on the sum of the molar fractions of (I): - O- (CH 2) m -O- ( wherein, m represents an integer of 8-10.) (III): —O—R ¹ —O— (wherein, R ¹ represents a primary glycol residue having 4 to 8 carbon atoms having a side chain.) (IV): —O— (CH ₂ ) ₄ — O- (In the formula, n represents an integer of 4 to 8.) (VI): —O— (CH ₂ ) ₄ —OH