JP7172684B2 - Polyurethane elastomer and its manufacturing method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polyurethane elastomer excellent in transparency, flexibility, mechanical strength and durability, and a method for producing this polyurethane elastomer.

Polyurethane elastomers include thermoplastic polyurethane elastomer (TPU), which softens when heated and then hardens when cooled, and thermosetting polyurethane elastomer (TSU), which hardens when heated, both of which have excellent elasticity and mechanical strength. , low-temperature properties, abrasion resistance, weather resistance, oil resistance, excellent processability, and can be easily processed into various shapes. In addition to OA equipment parts such as parts, paper feed rolls, rolls for copying machines, it is widely used for sports and leisure goods.

In Patent Document 1, diphenylmethane diisocyanate is used as a polyisocyanate compound, polycarbonate diol is used as a polyol, and three components having a specific molecular weight range of a diol, a polyether polyol, and a propylene oxide adduct of glycerin are used together as a curing agent. have proposed a two-liquid thermosetting polyurethane elastomer with improved mechanical strength (tensile strength, elongation), low compression strain, low impact resilience, water resistance, and the like.

Patent Document 2 describes a polyurethane elastomer with improved flexibility, strength, and water resistance, which is obtained by reacting a main agent obtained by reacting a polycarbonate polyol, a polyether polyol, and a polyisocyanate compound, and a curing agent such as 1,4-butanediol. A polyurethane elastomer using is proposed.

Patent Document 3 proposes a thermoplastic polyurethane elastomer obtained by reacting polyisocyanate and polyether carbonate diol as a thermoplastic polyurethane elastomer having oil lubrication resistance, tensile strength and optical properties.

JP 2013-163778 A JP 2015-081278 A JP-A-4-214713

Further improvements in flexibility and durability are desired for polyurethane elastomers in their uses. However, it is difficult to achieve compatibility between the two properties, and furthermore, the transparency is inferior.
That is, in conventional polyurethane elastomers, a combination of polyether polyol and polycarbonate diol has been proposed in order to impart flexibility, but due to the effect of mass transfer due to the low compatibility of the polyol during the urethanization reaction, In the solvent-free system, it was insufficient to obtain physical properties and design properties such as transparency of the obtained polyurethane elastomer molded article. For example, in the polyurethane elastomer synthesized by the method proposed in Patent Document 1, since the compatibility between polyols is poor, a polycarbonate diol is reacted with an isocyanate compound in advance to form a prepolymer, and then polytetramethylene glycol or the like is used. It had to be mixed with a curing agent, and the resulting polyurethane elastomer had an insufficient balance of physical properties among durability, flexibility and mechanical strength.

Patent Document 3 does not disclose a polyurethane elastomer using a combination of polyether polycarbonate diol and polycarbonate diol or polyalkylene ether glycol used in the present invention.

An object of the present invention is to provide a polyurethane elastomer excellent in transparency, flexibility, mechanical strength and durability.

As a result of intensive studies aimed at solving the above problems, the present inventors have found that by producing a polyurethane elastomer using a combination of a specific polyether polycarbonate diol and a polycarbonate diol or a polyalkylene ether glycol as polyol raw materials, the above-mentioned I found that the problem can be solved.

The present invention has been achieved based on such findings, and the gist thereof is as follows.

[1] A structural unit derived from a compound having multiple isocyanate groups, a structural unit derived from at least one compound selected from the group consisting of polyols and polyamines, and a polyether carbonate diol represented by the following formula (A) and a polycarbonate diol having at least a repeating unit represented by the following formula (B) and a repeating unit represented by the following formula (C) and/or a repeating unit represented by the following formula (D) and a structural unit derived from a polyalkylene ether glycol having a repeating unit represented by the following formula (E).

(In the above formula (A), R ¹ represents a divalent hydrocarbon group having 2 to 10 carbon atoms, n is an integer of 2 to 30, and m is an integer of 1 to 20. The formula ( In A), a plurality of R ¹ may be the same or different.)

（上記式（Ｂ）において、Ｒ^２は炭素数２～２０の二価の炭化水素基を表し、ｐは３～５０の整数であり、上記式（Ｃ）においてＲ^３はＲ^２とは異なるものであり、炭素数３～２０の二価の炭化水素基を表し、又は、脂環式構造若しくは複素環式構造を含む炭素数３～２０の二価の炭化水素基を表し、ｑは０～５０の整数である。
上記式（Ｄ）において、Ｒ^４は炭素数２～２０のアルキレン基、ｒは３～５０の整数であり、上記式（Ｅ）においてＲ^５はＲ^４とは異なるものであり、炭素数３～２０の二価の炭化水素基、又は、脂環式構造若しくは複素環式構造を含む炭素数３～２０の二価の炭化水素基を表し、ｓは０～５０の整数である。）

(In formula (B) above, R ² represents a divalent hydrocarbon group having 2 to 20 carbon atoms, p is an integer of 3 to 50, and R ³ is different from R ² in formula (C) above. represents a divalent hydrocarbon group having 3 to 20 carbon atoms, or represents a divalent hydrocarbon group having 3 to 20 carbon atoms containing an alicyclic structure or a heterocyclic structure, q is 0 ~50 integers.
In the above formula (D), R ⁴ is an alkylene group having 2 to 20 carbon atoms, r is an integer of 3 to 50, and in the above formula (E), R ⁵ is different from R ⁴ and has 3 carbon atoms. represents a divalent hydrocarbon group of up to 20 or a divalent hydrocarbon group of 3 to 20 carbon atoms containing an alicyclic structure or heterocyclic structure, and s is an integer of 0 to 50; )

[2] The ratio of the structural unit derived from the polyether polycarbonate diol to the total of the structural units derived from the polycarbonate diol and the structural units derived from the polyalkylene ether glycol is 10% by weight to 90% by weight [1] Polyurethane elastomer according to.

[3] The polyurethane elastomer according to [1] or [2], wherein R ¹ in formula (A) is an n-butylene group and/or a 2-methylbutylene group.

[4] Any one of [1] to [3], wherein the molar ratio of the repeating unit represented by the formula (C) to the repeating unit represented by the formula (B) is 0.03 to 10. polyurethane elastomer.

[5] The polyurethane elastomer according to any one of [1] to [4], wherein R ² in formula (B) is a divalent hydrocarbon group having 3 to 6 carbon atoms.

[6] The polyurethane elastomer according to any one of [1] to [5], wherein R ³ in formula (C) is a divalent hydrocarbon group having 4 to 12 carbon atoms.

[7] The structural unit derived from formula (C) is neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol and 2-methyl-1,4-butane The polyurethane elastomer according to any one of [1] to [5], which is a structural unit derived from at least one selected from the group consisting of diols.

[8] The structural unit derived from formula (C) is a structural unit derived from at least one selected from the group consisting of isosorbide, isomannide, isoidide, and 1,4-cyclohexanedimethanol [1] to The polyurethane elastomer according to any one of [5].

[9] The polyurethane elastomer according to any one of [1] to [8], wherein the structural unit derived from the polyalkylene ether glycol has a number average molecular weight of 200 to 5000 based on the hydroxyl value.

[10] The polyalkylene ether glycol is polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, copolymerized polytetramethylene ether glycol of 3-methyltetrahydrofuran and tetrahydrofuran, copolymerized polyether polyol of neopentyl glycol and tetrahydrofuran, ethylene The polyurethane elastomer according to any one of [1] to [9], which is at least one selected from the group consisting of copolymerized polyether polyols of oxide and tetrahydrofuran and copolymerized polyether glycols of propylene oxide and tetrahydrofuran.

[11] The polyurethane elastomer according to any one of [1] to [10], wherein the compound having a plurality of isocyanate groups is an aromatic diisocyanate compound.

[12] The polyurethane elastomer according to [11], wherein the aromatic diisocyanate compound is at least one selected from the group consisting of 4,4' -diphenylmethane diisocyanate, toluene diisocyanate and xylylene diisocyanate.

[13] wherein at least one compound selected from the group consisting of polyols and polyamines is at least one compound selected from the group consisting of ethylene glycol, 1,4-butanediol and 1,6-hexanediol; The polyurethane elastomer according to any one of [1] to [12].

[14] The polyurethane elastomer according to any one of [1] to [13], wherein the polyurethane elastomer is a thermoplastic elastomer.

[15] A method for producing a polyurethane elastomer according to any one of [1] to [14], wherein at least one selected from the group consisting of the compound having a plurality of isocyanate groups, the polyol and the polyamine A method for producing a polyurethane elastomer, wherein the addition polymerization reaction of the compound, the polycarbonate diol and/or the polyalkylene ether glycol is carried out without a solvent.

ADVANTAGE OF THE INVENTION According to this invention, the polyurethane elastomer excellent in transparency, flexibility, and durability is provided.
In the present invention, "durability" means chemical resistance, weather resistance, and resistance to various chemical and physical influences.

Embodiments of the present invention will be described in detail below, but the present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention.

[Polyurethane elastomer]
The polyurethane elastomer of the present invention comprises at least one compound (hereinafter referred to as "chain , a polyether polycarbonate diol having a structure represented by the following formula (A) (hereinafter sometimes referred to as a "polyether polycarbonate diol (A)"), and at least the following A repeating unit represented by the formula (B) (hereinafter sometimes referred to as "repeating unit (B)") and a repeating unit represented by the following formula (C) (hereinafter referred to as "repeating unit (C)") and/or a repeating unit represented by the following formula (D) (hereinafter sometimes referred to as “repeating unit (D)”) and a repeating unit represented by the following formula (E): (hereinafter sometimes referred to as "repeating unit (E)"). , a polyether polycarbonate diol (A), a polycarbonate diol having a repeating unit (B) and a repeating unit (C) and/or a polyalkylene ether glycol having a repeating unit (D) and a repeating unit (E) are used as raw materials. manufactured by

(In the above formula (A), R ¹ represents a divalent hydrocarbon group having 2 to 10 carbon atoms, n is an integer of 2 to 30, and m is an integer of 1 to 20. The formula ( In A), a plurality of R ¹ may be the same or different.)

(In formula (B) above, R ² represents a divalent hydrocarbon group having 2 to 20 carbon atoms, p is an integer of 3 to 50, and R ³ is different from R ² in formula (C) above. represents a divalent hydrocarbon group having 3 to 20 carbon atoms, or represents a divalent hydrocarbon group having 3 to 20 carbon atoms containing an alicyclic structure or a heterocyclic structure, q is 0 ~50 integers.
In the above formula (D), R ⁴ is an alkylene group having 2 to 20 carbon atoms, r is an integer of 3 to 50, and in the above formula (E), R ⁵ is different from R ⁴ and has 3 carbon atoms. represents a divalent hydrocarbon group of up to 20 or a divalent hydrocarbon group of 3 to 20 carbon atoms containing an alicyclic structure or heterocyclic structure, and s is an integer of 0 to 50; )

<Polyisocyanate compound>
The polyisocyanate compound used as a raw material for producing the polyurethane elastomer of the present invention may have two or more isocyanate groups, and includes various known aliphatic, alicyclic or aromatic polyisocyanate compounds.

For example, tetramethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate and dimer diisocyanate obtained by converting the carboxyl group of dimer acid to an isocyanate group. Aliphatic diisocyanate compounds; 1,4-cyclohexane diisocyanate, isophorone diisocyanate, 1-methyl-2,4-cyclohexane diisocyanate, 1-methyl-2,6-cyclohexane diisocyanate, 4,4′-dicyclohexylmethane diisocyanate and 1,3- Alicyclic diisocyanate compounds such as bis(isocyanatomethyl)cyclohexane; xylylene diisocyanate, 4,4'-diphenyl diisocyanate, toluene diisocyanate (2,4-toluene diisocyanate, 2,6-toluene diisocyanate), m-phenylene diisocyanate, p -phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, 3, aromatic diisocyanate compounds such as 3'-dimethyl-4,4'-biphenylene diisocyanate, polymethylene polyphenyl isocyanate, phenylene diisocyanate and m-tetramethylxylylene diisocyanate; These may be used individually by 1 type, and may use 2 or more types together.

Among these, aromatic polyisocyanate compounds are preferred because of their high reactivity with polyols and the curability of the resulting polyurethane elastomer. Diisocyanate (hereinafter sometimes referred to as "MDI"), toluene diisocyanate (TDI), and xylylene diisocyanate are preferred.

<Chain extender>
The chain extender used as a raw material for producing the polyurethane elastomer of the present invention is a low-molecular-weight compound having at least two active hydrogens that react with isocyanate groups, and is selected from polyols and polyamines.

Specific examples include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol and 1,9-nonanediol. , 1,10-decanediol, 1,12-dodecanediol, and other linear diols; 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl -1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, 2,4-heptanediol, 1,4-dimethylolhexane, 2-ethyl-1,3-hexanediol, 2 ,2,4-trimethyl-1,3-pentanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, dimer diol, and other branched diols diols having an ether group such as diethylene glycol and propylene glycol; diols having an alicyclic structure such as 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and 1,4-dihydroxyethylcyclohexane; xylylene glycol; Diols having aromatic groups such as 1,4-dihydroxyethylbenzene and 4,4′-methylenebis(hydroxyethylbenzene); Polyols such as glycerin, trimethylolpropane and pentaerythritol; N-methylethanolamine and N-ethylethanol hydroxyamines such as amine; ethylenediamine, 1,3-diaminopropane, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, 4,4'-diaminodicyclohexylmethane, 2-hydroxyethylpropylenediamine, di-2-hydroxy ethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, 4,4′-diphenylmethanediamine, methylenebis(o-chloroaniline), xylylenediamine, diphenyldiamine, tri polyamines such as diamine, hydrazine, piperazine, N,N'-diaminopiperazine;

One of these chain extenders may be used alone, or two or more thereof may be used in combination.

Among them, ethylene glycol, 1, 4-butanediol and 1,6-hexanediol are preferred.

<Polyether polycarbonate diol (A)>
The polyether polycarbonate diol (A) used as a raw material for producing the polyurethane elastomer of the present invention is represented by the following formula (A).
In the following formula (A), when m = 1, it is called "polyether carbonate diol" instead of "polyether polycarbonate diol", but in the present invention, it is represented by formula (A) The term "polyether polycarbonate diol (A)" also includes polyether carbonate diols.

(In the above formula (A), R ¹ represents a divalent hydrocarbon group having 2 to 10 carbon atoms, n is an integer of 2 to 30, and m is an integer of 1 to 20. The formula ( In A), a plurality of R ¹ may be the same or different.)

In the above formula (A), R ¹ is preferably a linear or branched alkylene group having 2 to 10 carbon atoms, more preferably 3 to 6 carbon atoms, and particularly preferably a butylene group having 4 carbon atoms or a A 2-methylbutylene group, particularly preferably an n-butylene group. That is, R ¹ —O— in formula (A) is preferably derived from polytetramethylene ether glycol from the viewpoint of industrial availability and excellent physical properties of the obtained polyurethane elastomer.

In the above formula (A), when n is less than 2, the flexibility of the resulting polyurethane elastomer tends to be poor. , the compatibility with other polyols deteriorates, and the obtained polyurethane elastomer tends to have low transparency. Therefore, n is 2-30, preferably 3-25, more preferably 3-20.

In the above formula (A), if m is less than 1, the durability of the polyurethane elastomer tends to be poor. Therefore, m is 1-20, preferably 2-10, more preferably 2-6.

Polyether polycarbonate diol (A) can be produced by polymerizing polyoxyalkylene glycol and a carbonate compound in the presence of a catalyst according to a conventional method.

Polyoxyalkylene glycols used in the production of polyether polycarbonate diol (A) include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, polytetramethylene ether glycol copolymerized with 3-methyltetrahydrofuran and tetrahydrofuran, neopentyl glycol and tetrahydrofuran. from the viewpoint of the mechanical strength of the resulting polyurethane elastomer, and polytetramethylene ether glycol (PTMG ) is more preferred.
In addition, said polyoxyalkylene glycol may use only 1 type, and may use 2 or more types together.

The number average molecular weight (Mn) determined from the hydroxyl value of the polyoxyalkylene glycol used for producing the polyether polycarbonate diol (A) is preferably 150 to 2000, more preferably 200 to 1500, still more preferably 250 to 1200. . If the molecular weight is less than 300, the flexibility of the resulting polyurethane elastomer tends to be poor. The transparency of the resulting polyurethane elastomer tends to be low due to poor compatibility with the polymer. The number average molecular weight (Mn) determined from the hydroxyl value is specifically measured by the method described in the section of Examples below.

Carbonate compounds that can be used in the production of the polyether polycarbonate diol (A) are not limited as long as they do not impair the effects of the present invention, and include dialkyl carbonates, diaryl carbonates, and alkylene carbonates. These may be of one type or plural types. Of these, dialkyl carbonates and alkylene carbonates are preferred from the viewpoint of reactivity.

Specific examples of carbonate compounds include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, diphenyl carbonate, ethylene carbonate and the like, with dimethyl carbonate and ethylene carbonate being preferred.

When producing the polyether polycarbonate diol (A), a transesterification catalyst can be used as necessary to promote polymerization.
As the transesterification catalyst, any compound generally considered to have transesterification ability can be used without limitation.

Examples of transesterification catalysts include compounds of long period periodic table (hereinafter simply referred to as "periodic table") Group 1 metals (excluding hydrogen) such as lithium, sodium, potassium, rubidium, and cesium; Compounds of Group 2 metals of the periodic table such as magnesium, calcium, strontium and barium; compounds of Group 4 metals of the periodic table such as titanium and zirconium; compounds of Group 5 metals of the periodic table such as hafnium; Group 9 metal compounds; periodic table group 12 metal compounds such as zinc; periodic table group 13 metal compounds such as aluminum; periodic table group 14 metal compounds such as germanium, tin, lead; antimony, bismuth, etc. compounds of Group 15 metals of the periodic table; and compounds of lanthanide metals such as lanthanum, cerium, europium, and ytterbium. Among these, from the viewpoint of increasing the transesterification reaction rate, periodic table group 1 metal compounds (excluding hydrogen), periodic table group 2 metal compounds, periodic table group 4 metal compounds, periodic table 5 Group metal compounds, periodic table group 9 metal compounds, periodic table group 12 metal compounds, periodic table group 13 metal compounds, periodic table group 14 metal compounds are preferred, and periodic table group 1 metals ( excluding hydrogen) and compounds of metals of Group 2 of the periodic table are more preferred, and compounds of metals of Group 2 of the periodic table are even more preferred. Among the compounds of Group 1 metals (excluding hydrogen) of the periodic table, lithium, potassium and sodium compounds are preferred, lithium and sodium compounds are more preferred, and sodium compounds are even more preferred. Among the compounds of Group 2 metals of the periodic table, compounds of magnesium, calcium and barium are preferred, compounds of calcium and magnesium are more preferred, and compounds of magnesium are even more preferred. These metal compounds are mainly used as hydroxides, salts and the like. Examples of salts when used as salts include halide salts such as chlorides, bromides and iodides; carboxylates such as acetates, formates and benzoates; inorganic acid salts such as carbonates and nitrates. sulfonates such as methanesulfonic acid, toluenesulfonic acid and trifluoromethanesulfonic acid; phosphorus-containing salts such as phosphates, hydrogen phosphates and dihydrogen phosphates; acetylacetonate salts; Catalyst metals can also be used as alkoxides such as methoxides and ethoxides.

Among these, preferably, at least one metal selected from group 2 metals of the periodic table, such as acetate, nitrate, sulfate, carbonate, phosphate, hydroxide, halide, acetylacetonate salt, Alkoxides are used, more preferably acetates, carbonates, hydroxides and acetylacetonate salts of Group 2 metals of the periodic table, more preferably acetates, carbonates and hydroxides of magnesium and calcium, Acetylacetonate salts are used, particularly preferably magnesium, calcium acetate and acetylacetonate salts, most preferably magnesium acetylacetonate.

In the production of the polyether polycarbonate diol (A), the amount of the carbonate compound used is not particularly limited. 50, more preferably 0.60, and the upper limit is preferably 1.00, more preferably 0.98, still more preferably 0.97. If the amount of the carbonate compound used exceeds the above upper limit, the proportion of polyether polycarbonate diols (A) whose terminal groups are not hydroxyl groups may increase, or the molecular weight may not fall within the predetermined range. Polymerization may not proceed until

When the transesterification catalyst described above is used in the production of the polyether polycarbonate diol (A), it is preferably used in an amount that does not affect the performance even if it remains in the resulting polycarbonate diol.

The upper limit of the amount of the transesterification catalyst used is preferably 500 ppm by weight, more preferably 100 ppm by weight, and more preferably 50 ppm by weight, as the weight ratio of the metal to the weight of the raw material polyoxyalkylene glycol. More preferably, 10 ppm by weight is particularly preferable. On the other hand, the lower limit is preferably 0.01 ppm by weight, more preferably 0.1 ppm by weight, and even more preferably 1 ppm by weight, as the amount at which sufficient polymerization activity can be obtained.

The reaction temperature for the transesterification reaction can be arbitrarily adopted as long as it is a temperature at which a practical reaction rate can be obtained. The lower limit of the normal reaction temperature is preferably 70°C, more preferably 100°C, and even more preferably 130°C. The upper limit of the reaction temperature is generally preferably 250°C, more preferably 230°C, and even more preferably 200°C. By setting the reaction temperature to the upper limit or lower, it is possible to prevent quality problems such as coloring of the obtained polyether polycarbonate diol (A) and generation of an ether structure.

Furthermore, the reaction temperature is preferably 180° C. or lower, more preferably 170° C. or lower, and further preferably 160° C. or lower throughout the entire transesterification process for producing the polyether polycarbonate diol (A). preferable. By keeping the reaction temperature at 180° C. or lower throughout the entire process, it is possible to prevent coloration from occurring depending on the conditions.

Although the transesterification reaction can be carried out under normal pressure, the transesterification reaction is an equilibrium reaction, and the reaction can be biased toward the production system by distilling off the low-boiling components to be produced out of the system. Therefore, in the latter half of the reaction, it is usually preferable to adopt reduced pressure conditions and carry out the reaction while distilling off the low-boiling components. Alternatively, it is also possible to carry out the reaction while gradually lowering the pressure from the middle of the reaction to distill off the low-boiling components produced. In particular, it is preferable to carry out the reaction by increasing the degree of pressure reduction in the final stage of the reaction, because by-products such as monoalcohols, phenols and cyclic carbonates can be distilled off.
In this case, the upper limit of the reaction pressure at the end of the reaction is preferably 10 kPa, more preferably 5 kPa, and even more preferably 1 kPa.
In order to effectively distill off the light-boiling components, the reaction can be carried out while passing an inert gas such as nitrogen, argon and helium through the reaction system.

When a low-boiling carbonate compound is used in the transesterification reaction, the initial reaction is carried out near the boiling point of the carbonate compound, and as the reaction progresses, the temperature is gradually raised to allow the reaction to proceed further. methods can also be employed. By doing so, it is possible to prevent the unreacted carbonate compound from being distilled off in the initial stage of the reaction.

Furthermore, in order to prevent these raw materials from being distilled off, it is possible to attach a reflux pipe to the reactor and carry out the reaction while refluxing the carbonate compound. can be adjusted to

The polymerization reaction can be carried out in a batch system or a continuous system, but is preferably carried out in a continuous system from the viewpoint of product stability and the like. The apparatus to be used may be of any type of tank type, tubular type or tower type, and known polymerization tanks equipped with various stirring blades and the like can be used. The atmosphere during heating of the device is not particularly limited, but from the viewpoint of product quality, it is preferable to carry out the heating in an inert gas such as nitrogen gas under normal pressure or reduced pressure.

The polymerization reaction is terminated when the target molecular weight is reached while measuring the molecular weight of the polyether polycarbonate diol (A) to be produced. The reaction time required for polymerization varies greatly depending on the polyoxyalkylene glycol used, the carbonate compound, and the presence or absence and type of catalyst used. It is more preferably 30 hours or less, and even more preferably 20 hours or less.

When a catalyst is used in the polymerization reaction, the catalyst usually remains in the obtained polyether polycarbonate diol (A), and the remaining catalyst may make it impossible to control the polyurethane formation reaction. In order to suppress the influence of this remaining catalyst, it is preferable to add a catalyst deactivator such as a phosphorus-based compound in a molar amount substantially equal to that of the transesterification catalyst used to deactivate the transesterification catalyst. Furthermore, after adding the catalyst deactivator, the transesterification catalyst can be efficiently deactivated by heat treatment or the like as described later.

Phosphorus compounds used to inactivate transesterification catalysts include, for example, inorganic phosphoric acids such as phosphoric acid and phosphorous acid, dibutyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, Examples thereof include organic phosphates such as triphenyl phosphate. These may be used individually by 1 type, and may use 2 or more types together.

The amount of the phosphorus-based compound used is not particularly limited, but may be approximately equimolar to the used ester exchange catalyst. Specifically, the upper limit is preferably It is 5 mol, more preferably 2 mol, and the lower limit is preferably 0.8 mol, more preferably 1.0 mol. If the phosphorus-based compound is used in an amount less than this, the deactivation of the transesterification catalyst in the reaction product is insufficient, and the obtained polyether polycarbonate diol (A) is used as a raw material for producing a polyurethane elastomer. In some cases, the reactivity of the polyether polycarbonate diol (A) with respect to isocyanate groups cannot be sufficiently lowered. Also, if a phosphorus compound exceeding this range is used, the obtained polyether polycarbonate diol (A) may be colored.

Deactivation of the transesterification catalyst by adding a phosphorus-based compound can be performed at room temperature, but is more efficient with heat treatment. The temperature of this heat treatment is not particularly limited, but the upper limit is preferably 180° C., more preferably 150° C., still more preferably 120° C., particularly preferably 100° C., and the lower limit is preferably 50° C., more preferably 50° C. is 60°C, more preferably 70°C. If the temperature is lower than this, deactivation of the transesterification catalyst takes a long time and is not efficient, and the degree of deactivation may be insufficient. On the other hand, at temperatures exceeding 180°C, the obtained polyether polycarbonate diol (A) may be colored. Although the reaction time with the phosphorus compound is not particularly limited, it is usually 1 to 5 hours.

The amount of the catalyst remaining in the polyether polycarbonate diol (A) is preferably 100 ppm by weight or less, particularly 10 ppm by weight or less in terms of metal, from the viewpoint of controlling the polyurethane formation reaction. On the other hand, it is preferable that the required amount of catalyst is 0.01 weight ppm or more, particularly 0.1 weight ppm or more, and particularly 5 weight ppm or more in terms of metal.

In the polyether polycarbonate diol (A), the carbonate compound used as a raw material during production may remain. The amount of the carbonate compound remaining in the polyether polycarbonate diol (A) is not limited, but is preferably as small as possible. , more preferably 1% by weight. If the content of the carbonate compound in the polyether polycarbonate diol (A) is too high, the reaction during polyurethane formation may be inhibited. On the other hand, the lower limit is not particularly limited, but is preferably 0.1% by weight, more preferably 0.01% by weight, and still more preferably 0% by weight.

Polyoxyalkylene glycol used during production may remain in the polyether polycarbonate diol (A). The amount of polyoxyalkylene glycol remaining in the polyether polycarbonate diol (A) is not limited, but is preferably as small as possible. is 0.1% by weight or less, more preferably 0.05% by weight or less. If the residual amount of polyoxyalkylene glycol in the polyether polycarbonate diol (A) is large, the molecular length of the soft segment portion of the polyurethane elastomer may be insufficient, and desired physical properties may not be obtained.

The lower limit of the hydroxyl value of the polyether polycarbonate diol (A) is usually 22.4 mg-KOH/g, preferably 28.1 mg-KOH/g, more preferably 37.4 mg-KOH/g, and the upper limit is usually 187.0 mg. -KOH/g, preferably 140.3 mg-KOH/g, more preferably 112.2 mg-KOH/g. If the hydroxyl value is less than the above lower limit, the viscosity becomes too high and handling may become difficult during polyurethane formation. If the above upper limit is exceeded, the flexibility of the obtained polyurethane elastomer may be insufficient.
Specifically, the hydroxyl value of the polyether polycarbonate diol (A) is measured by the method described in the Examples section below.

The lower limit of the number average molecular weight (Mn) obtained from the hydroxyl value of the polyether polycarbonate diol used in the present invention is preferably 600, more preferably 800, still more preferably 1,000. On the other hand, the upper limit is preferably 5,000, more preferably 4,000, still more preferably 3,000. If the Mn of the polyether polycarbonate diol is less than the above lower limit, the resulting polyurethane elastomer may not have sufficient flexibility. On the other hand, when the above upper limit is exceeded, the viscosity increases, which may impair the handling during polyurethane formation.

<Polycarbonate Diol>
The polycarbonate diol used as a raw material for producing the polyurethane elastomer of the present invention (hereinafter sometimes referred to as the "polycarbonate diol of the present invention") comprises repeating units (B) represented by the following formula (B) and ) has a repeating unit (C). In formula (C), when q is 0, the repeating unit (C) does not exist in the polycarbonate diol of the present invention.

(In formula (B) above, R ² represents a divalent hydrocarbon group having 2 to 20 carbon atoms, p is an integer of 3 to 50, and R ³ is different from R ² in formula (C) above. represents a divalent hydrocarbon group having 3 to 20 carbon atoms, or represents a divalent hydrocarbon group having 3 to 20 carbon atoms containing an alicyclic structure or a heterocyclic structure, q is 0 It is an integer from ~50.)

In the repeating unit (B), R ² is preferably a linear or branched alkylene group having 3 to 12 carbon atoms, more preferably 3 to 6 carbon atoms, particularly preferably 4 or 6 carbon atoms, and the repeating unit (B ) is preferably derived from 1,4-butanediol, 1,5-pentanediol, or 1,6-hexanediol from the viewpoint of industrial availability and excellent physical properties of the resulting polyurethane elastomer. An n-butylene group and an n-hexylene group are particularly preferred.

In the repeating unit (B), when p is less than 3, the compatibility with other polyols tends to decrease, and the resulting polyurethane elastomer tends to have poor flexibility and durability. be. Therefore, p is 3-50, preferably 3-40, more preferably 5-30.

R ³ of the repeating unit (C) is a divalent hydrocarbon group having 3 to 20 carbon atoms, preferably 4 to 12 carbon atoms, and may be a linear alkylene group. By using a chain aliphatic dihydroxy compound, it can be introduced into a polycarbonate diol. Specific examples of the linear aliphatic dihydroxy compound include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, preferably 1,4-butane One or more of diols, 1,5-pentadiol, 1,6-hexanediol, and 1,10-decanediol can be used.

R ³ of the repeating unit (C) may also be an alkylene group having 3 to 20 carbon atoms, preferably 4 to 12 carbon atoms, including a branched chain. Such branched alkylene groups include neopentyl glycol, 3-methyl -1,5-pentanediol, 2-methyl-1,3-propanediol and 2-methyl-1,4-butanediol derived from one or more of them.

Furthermore, R ³ of the repeating unit (C) may be an aliphatic hydrocarbon group containing an alicyclic structure or a heterocyclic structure, specifically one of isosorbide, isomannide, isoidide and 1,4-cyclohexanedimethanol. Or those derived from two or more kinds.

In the repeating unit (C), when q is 0 and the polycarbonate diol of the present invention does not contain the repeating unit (C), the compatibility with other polyols is lowered, and the flexibility and durability of the resulting polyurethane elastomer are reduced. If it exceeds 50, the wear resistance tends to be poor. Therefore, m is preferably 1-50, more preferably 2-50, even more preferably 2-40, and particularly preferably 2-30.

The polycarbonate diol of the present invention may contain only one type of repeating unit (B), or may contain two or more types. In addition, only one kind of repeating unit (C) may be contained, or two or more kinds thereof may be contained. Moreover, the repeating unit (B) and the repeating unit (C) may have the same structure.

Further, the polycarbonate diol of the present invention contains repeating units other than the repeating unit (B) and the repeating unit (C), for example, 5.0 mol % or less in all repeating units, within a range that does not impair the effects of the present invention. It may be

The molar ratio of the repeating unit (C) to the repeating unit (B) contained in the polycarbonate diol of the present invention (repeating unit (C)/repeating unit (B), sometimes referred to as "molar ratio (C)/(B)") ) is preferably 0.03 to 10, particularly preferably 0.05 to 4, and most preferably 0.10 to 1.00. If the repeating unit (B) is more than the above range and the repeating unit (C) is less, the compatibility with other polyols tends to decrease. If it is too much, the flexibility of the obtained polyurethane elastomer, especially at low temperatures, and chemical resistance tend to decrease.
The molar ratio (C)/(B) of the polycarbonate diol is measured by the method described in Examples below.

The polycarbonate diol of the present invention is, for example, a linear aliphatic dihydroxy compound having 2 to 20 carbon atoms, preferably 3 to 6 carbon atoms, for introducing the repeating unit (B), specifically 1,3-propane. Diol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol or 2 or more, and a branched aliphatic dihydroxy compound having 3 to 20 carbon atoms, preferably 4 to 12 carbon atoms, for introducing the repeating unit (C), preferably neopentyl glycol, 3-methyl-1,5-pentane Diol, 2-methyl-1,3-propanediol, 2-methyl-1,4-butanediol, or alicyclic or heterocyclic structures such as isosorbide, isomannide, isoidide, 1,4-cyclohexanedimethanol and one or more of an aliphatic dihydroxy compound containing It can be produced by a polymerization reaction in the presence of a catalyst according to a conventional method.

The carbonate compound that can be used to produce the polycarbonate diol of the present invention is not limited as long as it does not impair the effects of the present invention, and includes dialkyl carbonate, diaryl carbonate and alkylene carbonate. These may be of one type or plural types. Among these, diaryl carbonate is preferable from the viewpoint of reactivity.

Specific examples of carbonate compounds include dimethyl carbonate, diethyl carbonate, dibutyl carbonate, diphenyl carbonate, ethylene carbonate and the like, with diphenyl carbonate being preferred.

The polycarbonate diol of the present invention is obtained by introducing a dihydroxy compound and repeating units (C) for introducing the repeating units (B) instead of polyoxyalkylene glycol in the above-described method for producing the polyether polycarbonate diol (A). It can be produced in the same manner except for using a dihydroxy compound for

The amount of the catalyst remaining in the polycarbonate diol of the present invention is preferably 100 ppm by weight or less, particularly 10 ppm by weight or less in terms of metal conversion, from the viewpoint of controlling the polyurethane formation reaction. On the other hand, it is preferable that the required amount of catalyst is 0.01 weight ppm or more, particularly 0.1 weight ppm or more, and particularly 5 weight ppm or more in terms of metal.

In the production of the polycarbonate diol of the present invention, the reaction products include impurities having no hydroxyl group at the polymer terminal in the product, phenols, raw material dihydroxy compounds, carbonate compounds, by-produced low-boiling cyclic carbonates, and added It can be purified for the purpose of removing catalysts and the like.

For the purification at that time, a method of distilling off light boiling compounds by distillation can be adopted. Specific methods of distillation include reduced-pressure distillation, steam distillation, thin-film distillation, and the like, and any method can be employed without particular limitation. Among them, thin-film distillation is most effective.

The conditions for thin film distillation are not particularly limited, but the upper limit of the temperature during thin film distillation is preferably 250°C, more preferably 200°C. Also, the lower limit is preferably 120°C, more preferably 150°C.
By setting the lower limit of the temperature during thin-film distillation to the above value, the effect of removing light-boiling components becomes sufficient. Further, by setting the upper limit to 250° C., it is possible to prevent the polycarbonate diol obtained after thin-film distillation from being colored.

The upper limit of the pressure during thin film distillation is preferably 500 Pa, more preferably 150 Pa, even more preferably 70 Pa, and particularly preferably 60 Pa. By setting the pressure during thin-film distillation to the above upper limit or less, a sufficient effect of removing light-boiling components can be obtained.

In addition, the upper limit of the temperature for keeping the polycarbonate diol immediately before thin film distillation is preferably 250°C, more preferably 150°C. Also, the lower limit is preferably 80°C, more preferably 120°C.
By setting the temperature at which the polycarbonate diol is kept warm just before the thin film distillation to be equal to or higher than the above lower limit, it is possible to prevent the fluidity of the polycarbonate diol from decreasing just before the thin film distillation. On the other hand, by making the amount equal to or less than the above upper limit, it is possible to prevent the polycarbonate diol obtained after thin-film distillation from being colored.

Also, in order to remove water-soluble impurities, washing may be performed with water, alkaline water, acidic water, a chelating agent-dissolved solution, or the like. In that case, the compound to be dissolved in water can be arbitrarily selected.

When a diaryl carbonate such as diphenyl carbonate is used as a starting material, phenols are by-produced during the production of polycarbonate diol. Since phenols are monofunctional compounds, they may become an inhibitory factor in the production of polyurethane elastomers. There is a possibility that the isocyanate and phenols will be regenerated and cause problems. Moreover, since phenols are also stimulating substances, it is preferable that the residual amount of phenols in the polycarbonate diol is as small as possible. Specifically, the residual amount of phenols in the polycarbonate diol is preferably 1000 ppm or less, more preferably 500 ppm or less, still more preferably 300 ppm or less, and most preferably 100 ppm or less as a weight ratio to the polycarbonate diol. In order to reduce the amount of phenols in the polycarbonate diol, as described above, the pressure for the polymerization reaction of the polycarbonate diol should be set to a high vacuum of 1 kPa or less in terms of absolute pressure, or thin film distillation or the like should be performed after the polymerization reaction of the polycarbonate diol. is valid.

A carbonate compound used as a raw material in manufacturing may remain in the polycarbonate diol. The amount of the carbonate compound remaining in the polycarbonate diol is not limited, but is preferably as small as possible. be. If the content of the carbonate compound in the polycarbonate diol is too high, the reaction during polyurethane formation may be inhibited. On the other hand, the lower limit is not particularly limited, but is preferably 0.1% by weight, more preferably 0.01% by weight, and still more preferably 0% by weight.

A dihydroxy compound used during production may remain in the polycarbonate diol. The amount of the dihydroxy compound remaining in the polycarbonate diol is not limited, but is preferably as small as possible. is 0.05% by weight or less. When the residual amount of the dihydroxy compound in the polycarbonate diol is large, the molecular length of the soft segment portion of the polyurethane elastomer becomes insufficient, and desired physical properties may not be obtained.

Polycarbonate diols sometimes contain cyclic carbonates (cyclic oligomers) that are by-produced during production. For example, when 2,2-dialkyl-1,3-propanediol is used as the starting dihydroxy compound for the repeating unit (B) or (C), 5,5-dialkyl-1,3-dioxan-2-one or further may form a cyclic carbonate with two or more molecules and be contained in the polycarbonate diol. More specifically, when 2,2-dimethyl-1,3-propanediol is used, 5,5-dimethyl-1,3-dioxan-2-one or a cyclic carbonate containing two or more molecules thereof and the like may be generated and contained in the polycarbonate diol. These compounds may cause side reactions in the polyurethane formation reaction and cause turbidity. It is preferable to remove as much as possible by performing thin film distillation or the like afterwards. The content of the cyclic carbonate such as 5,5-dialkyl-1,3-dioxan-3-one contained in the polycarbonate diol is not limited, but the weight ratio to the polycarbonate diol is preferably 3% by weight or less, more preferably It is 1% by weight or less, more preferably 0.5% by weight or less.

The hydroxyl value of the polycarbonate diol of the present invention has a lower limit of usually 22.4 mg-KOH/g, preferably 28.1 mg-KOH/g, more preferably 37.4 mg-KOH/g, and an upper limit of usually 448.8 mg-KOH/g. KOH/g, preferably 374.0 mg-KOH/g, more preferably 280.5 mg-KOH/g. If the hydroxyl value is less than the above lower limit, the viscosity becomes too high and handling may become difficult during polyurethane formation. If the above upper limit is exceeded, the flexibility of the obtained polyurethane elastomer may be insufficient.
Specifically, the hydroxyl value of the polycarbonate diol is measured by the method described in the Examples section below.

The lower limit of the number average molecular weight (Mn) obtained from the hydroxyl value of the polycarbonate diol of the present invention is preferably 250, more preferably 300, still more preferably 400. On the other hand, the upper limit is preferably 5,000, more preferably 4,000, still more preferably 3,000. If the Mn of the polycarbonate diol is less than the above lower limit, the resulting polyurethane elastomer may not have sufficient flexibility. On the other hand, when the above upper limit is exceeded, the viscosity increases, which may impair the handling during polyurethane formation.
Specifically, the number average molecular weight (Mn) determined from the hydroxyl value of the polycarbonate diol is measured by the method described in the Examples section below.

Only one type of polycarbonate diol may be used as a raw material for producing the polyurethane elastomer of the present invention, or two or more types having different repeating units, molar ratios thereof, physical properties, and the like may be used.

<Polyalkylene ether glycol>
The polyalkylene ether glycol (hereinafter sometimes referred to as "the polyalkylene ether glycol of the present invention") used as a raw material for producing the polyurethane elastomer of the present invention is a repeating unit (D) represented by the following formula (D). It has a repeating unit (E) represented by the following formula (E). In addition, in the formula (E), when s is 0, the repeating unit (E) does not exist in the polyalkylene ether glycol of the present invention.

(In the above formula (D), R ⁴ is an alkylene group having 2 to 20 carbon atoms, r is an integer of 3 to 50, and in the above formula (E), R ⁵ is different from R ⁴ , and the number of carbon atoms represents a divalent hydrocarbon group of 3 to 20, or a divalent hydrocarbon group of 3 to 20 carbon atoms containing an alicyclic structure or heterocyclic structure, and s is an integer of 0 to 50.)

A polyalkylene ether glycol is usually a polyhydroxy compound having one or more ether bonds in the main skeleton in the molecule, as in the repeating units (D) and (E).

From the viewpoint of industrial availability, R ⁴ in the repeating unit (D) is preferably an alkylene group having 2 to 4 carbon atoms, and r is preferably 3 to 100, particularly preferably 3 to 50.
From the viewpoint of compatibility with other polyols, in the repeating unit (E), R ⁵ is preferably a 2-butylene group or a neopentylene group, and s is preferably 0-30, particularly 0-20.

The molar ratio of the repeating unit (E) to the repeating unit (D) contained in the polyalkylene ether glycol of the present invention (repeating unit (E)/repeating unit (D), referred to as "molar ratio (E)/(D)" ) is preferably from 0 to 50, particularly preferably from 0 to 40, and most preferably from 0 to 30. If the repeating unit (E) is more than the above range, the viscosity may become too high, making it difficult to handle during polyurethane formation.
The molar ratio (E)/(D) of the polyalkylene ether glycol is measured by the same method as the method for measuring the molar ratio (B)/(A) of the polycarbonate diol described in the Examples section below. .

Examples of repeating units in the main skeleton of the polyalkylene ether glycol of the present invention include 1,2-ethylene glycol units, 1,2-propylene glycol units, 1,3-propanediol (trimethylene glycol) units, 2- methyl-1,3-propanediol unit, 2,2-dimethyl-1,3-propanediol unit, 1,4-butanediol (tetramethylene glycol) unit, 2-methyl-1,4-butanediol unit, 3 -methyl-1,4-butanediol unit, 3-methyl-1,5-pentanediol unit, neopentyl glycol unit, 1,6-hexanediol unit, 1,7-heptanediol unit, 1,8-octanediol Units, 1,9-nonanediol units, 1,10-decanediol units and 1,4-cyclohexanedimethanol units and other saturated hydrocarbon groups having 1 to 20 carbon atoms may be mentioned, and a single repeating unit is a polyalkylene ether. It may form a glycol, or two or more repeating units may form a copolymerized polyalkylene ether glycol.

The polyalkylene ether glycol used in the present invention includes polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, copolymerized polytetrahydrofuran of 3-methyltetrahydrofuran and tetrahydrofuran, among the polyalkylene ether glycols having the repeating unit in the main skeleton. Methylene ether glycol, neopentyl glycol-tetrahydrofuran copolymer polyether polyol, ethylene oxide-tetrahydrofuran copolymer polyether polyol, propylene oxide-tetrahydrofuran copolymer polyether glycol, etc. are preferable from the viewpoint of mechanical strength of the resulting polyurethane elastomer. , polytetramethylene ether glycol (PTMG) is more preferred.

The molecular weight of the polyalkylene ether glycol of the present invention is usually 200 or more, preferably 300 or more, more preferably 400 or more, still more preferably 500 or more, and the upper limit is usually 5000 or less, preferably 4000, based on the hydroxyl value. Below, more preferably 3500 or less, still more preferably 2500 or less.

By setting the molecular weight of the polyalkylene ether glycol to the above upper limit or less, the viscosity is suppressed and the handleability during polyurethane formation is not impaired. It is preferable because it provides sufficient flexibility when made into an elastomer.
The hydroxyl value-based molecular weight of the polyalkylene ether glycol is usually and specifically measured by the method described in the Examples section below.

These polyalkylene ether glycols may be used singly or in combination of two or more.

<Proportion of Use of Polyether Polycarbonate Diol (A) to Polycarbonate Diol of the Present Invention and/or Polyalkylene Ether Glycol of the Present Invention>
The ratio of the polyether polycarbonate diol (A) used for producing the polyurethane elastomer of the present invention to the polycarbonate diol (A) of the present invention and/or the polyalkylene ether glycol of the present invention is The ratio of the polyether polycarbonate diol (A) to the total of the polycarbonate diol of the present invention and the polyalkylene ether glycol of the present invention (hereinafter sometimes referred to as "PEPCD ratio") is 10% to 90% by weight. ratio. Either one or both of the polycarbonate diol of the present invention and the polyalkylene ether glycol of the present invention may be used.

When the PEPCD ratio is at least the above lower limit, the compatibility between the polyether polycarbonate diol (A) and the polycarbonate diol of the present invention and/or the polyalkylene ether glycol of the present invention is improved, resulting in high transparency and chemical resistance. If it is equal to or less than the above upper limit, excellent flexibility and mechanical strength can be obtained, and effects such as elastic recovery can be sufficiently obtained. The PEPCD proportion is preferably between 20% and 80% by weight, especially between 30% and 70% by weight.

[Method for producing polyurethane elastomer]
The polyurethane elastomer of the present invention comprises a polyether polycarbonate diol (A), the polycarbonate diol of the present invention and/or the polyalkylene ether glycol of the present invention (hereinafter, the polycarbonate diol of the present invention and the polyalkylene ether glycol of the present invention are referred to as " It may be referred to as "the diol of the present invention".), a polyisocyanate compound, and the above-described chain extender, but can be produced by a normal polyurethane reaction.
Here, if a solvent is used in the production of the polyurethane elastomer of the present invention, it is not industrially advantageous because it requires a step of removing the solvent during molding. Moreover, since a solvent has a large load on the environment, it is preferable to carry out the reaction without a solvent (in the absence of a solvent).
In the present invention, by using a polyether polycarbonate diol (A) that is highly compatible with both the polycarbonate diol and the polyalkylene glycol of the present invention such as polytetramethylene glycol, the effect of mass transfer is large under solvent-free conditions. However, it is possible to obtain a polyurethane elastomer that is uniform and has an excellent balance of physical properties.

For example, the polyurethane elastomer of the present invention can be produced by reacting the polyether polycarbonate diol (A) and the diol of the present invention with a polyisocyanate compound and a chain extender at a temperature ranging from room temperature to 200°C.
Alternatively, the polyether polycarbonate diol (A) and the diol of the present invention are first reacted with an excess polyisocyanate compound to produce a prepolymer having terminal isocyanate groups, and then a chain extender is used to increase the degree of polymerization. , the polyurethane elastomer of the present invention can be produced.

<Chain terminating agent>
When producing the polyurethane elastomer of the present invention, a chain terminating agent having one active hydrogen group can be used as necessary for the purpose of controlling the molecular weight of the resulting polyurethane.
These chain terminators include aliphatic monools having one hydroxyl group such as methanol, ethanol, propanol, butanol and hexanol, diethylamine, dibutylamine, n-butylamine, monoethanolamine and diethanolamine having one amino group. , morpholine, and other aliphatic monoamines.
These may be used individually by 1 type, and may use 2 or more types together.

<Catalyst>
In the polyurethane-forming reaction for producing the polyurethane elastomer of the present invention, an amine-based catalyst such as triethylamine, N-ethylmorpholine and triethylenediamine, or an acid-based catalyst such as acetic acid, phosphoric acid, sulfuric acid, hydrochloric acid and sulfonic acid, and trimethyltinlau are used. Known urethane polymerization catalysts typified by tin-based compounds such as dibutyltin dilaurate, dioctyltin dilaurate, and dioctyltin dineodecanate, and organic metal salts such as titanium-based compounds can also be used. A urethane polymerization catalyst may be used individually by 1 type, and may use 2 or more types together.

<Polyether polycarbonate diol (A) and polyol other than the diol of the present invention>
In the polyurethane-forming reaction when producing the polyurethane elastomer of the present invention, the polyether polycarbonate diol (A) and the diol of the present invention may be used in combination with other polyols, if necessary. Here, the polyether polycarbonate diol (A) and the polyol other than the diol of the present invention are not particularly limited as long as they are used in ordinary polyurethane production, and examples include polyester polyols, polycaprolactone polyols, and the polycarbonate of the present invention. Examples include polycarbonate polyols other than diols. Here, the weight ratio of the polyether polycarbonate diol (A) and the diol of the present invention with respect to the combined weight of the polyether polycarbonate diol (A), the diol of the present invention and other polyols is preferably 70% or more, preferably 90%. The above is more preferable. If the weight ratio of the polyether polycarbonate diol (A) and the diol of the present invention is too small, the flexibility and durability of the polyurethane elastomer, which are features of the present invention, may be lost.

In the present invention, the polycarbonate diol used in the present invention may be modified and used for the production of the polyurethane elastomer. Examples of modifying polycarbonate diol include a method of adding epoxy compounds such as ethylene oxide, propylene oxide and butylene oxide to polycarbonate diol to introduce ether groups, and a method of adding polycarbonate diol to cyclic lactone such as ε-caprolactone, adipic acid, and succinic acid. , sebacic acid, terephthalic acid, etc. and their ester compounds to introduce an ester group. Ether modification is preferable because modification with ethylene oxide, propylene oxide, or the like reduces the viscosity of the polycarbonate diol, and is therefore easy to handle. In particular, by modifying the polycarbonate diol of the present invention with ethylene oxide or propylene oxide, the crystallinity of the polycarbonate diol is lowered and the flexibility at low temperatures is improved. The water absorption and moisture permeability of the polyurethane elastomer may be improved. However, when the addition amount of ethylene oxide or propylene oxide is increased, various physical properties such as mechanical strength, heat resistance and chemical resistance of the polyurethane elastomer produced using the modified polycarbonate diol are lowered. 5% to 50% by weight is suitable, preferably 5% to 40% by weight, more preferably 5% to 30% by weight. Also, the method of introducing an ester group is preferable because modification with ε-caprolactone lowers the viscosity of the polycarbonate diol, and it is easy to handle. The amount of ε-caprolactone added to the polycarbonate diol is preferably 5% to 50% by weight, preferably 5% to 40% by weight, more preferably 5% to 30% by weight. When the amount of ε-caprolactone added exceeds 50% by weight, the hydrolysis resistance, chemical resistance, etc. of the polyurethane elastomer produced using the modified polycarbonate diol are lowered.

<Polyurethane elastomer manufacturing method>
As a method for producing the polyurethane elastomer of the present invention using the above-mentioned reaction reagents, a production method that is generally used experimentally or industrially can be used.
Examples thereof include a method of collectively mixing and reacting the polyether polycarbonate diol (A) and the diol of the present invention, other polyols used as necessary, a polyisocyanate compound and a chain extender (hereinafter referred to as "one step First, the polyether polycarbonate diol (A) and the diol of the present invention, other polyols and polyisocyanate compounds used as necessary are reacted to form a prepolymer having isocyanate groups at both ends. and then reacting the prepolymer with a chain extender (hereinafter sometimes referred to as "two-step method").

In the two-stage method, the polyether polycarbonate diol (A), the diol of the present invention, and other polyols are reacted in advance with 1 equivalent or more of a polyisocyanate compound to obtain isocyanate at both ends of the portion corresponding to the soft segment of the polyurethane. It goes through the process of preparing an intermediate. In this way, if the prepolymer is once prepared and then reacted with a chain extender, it may be easier to adjust the molecular weight of the soft segment portion, and it is useful when it is necessary to ensure phase separation between the soft segment and the hard segment. is useful.

<Single step method>
The one-step method, also called a one-shot method, is a method in which the polyether polycarbonate diol (A), the diol of the present invention, other polyols, a polyisocyanate compound, and a chain extender are charged all at once to carry out the reaction.
The amount of the polyisocyanate compound used in the one-step method is not particularly limited, but the total number of hydroxyl groups of the polyether polycarbonate diol (A) and the diol of the present invention and other polyols, the number of hydroxyl groups and the number of amino groups of the chain extender When the sum of the and is 1 equivalent, the lower limit is preferably 0.7 equivalents, more preferably 0.8 equivalents, still more preferably 0.9 equivalents, particularly preferably 0.95 equivalents, and the upper limit is preferably is 3.0 equivalents, more preferably 2.0 equivalents, still more preferably 1.5 equivalents, and particularly preferably 1.1 equivalents.

If the amount of polyisocyanate compound used is too large, unreacted isocyanate groups will cause side reactions, and the resulting polyurethane elastomer will tend to have too high a viscosity, making it difficult to handle or impairing its flexibility. If it is too small, the molecular weight of the polyurethane elastomer will not be sufficiently large, and there will be a tendency that sufficient strength cannot be obtained.

The amount of the chain extender used is not particularly limited, but one equivalent is obtained by subtracting the total number of hydroxyl groups of the polyether polycarbonate diol (A), the diol of the present invention, and other polyols from the number of isocyanate groups of the polyisocyanate compound. , the lower limit is preferably 0.7 equivalents, more preferably 0.8 equivalents, more preferably 0.9 equivalents, particularly preferably 0.95 equivalents, and the upper limit is preferably 3.0 equivalents, more It is preferably 2.0 equivalents, more preferably 1.5 equivalents, and particularly preferably 1.1 equivalents. If the amount of chain extender used is too large, the resulting polyurethane elastomer tends to be difficult to dissolve in the solvent and processing becomes difficult. In some cases, the elastic retention performance may not be obtained, or the heat resistance may be deteriorated.

<Two step method>
The two-step method, also called a prepolymer method, mainly includes the following methods.
(a) the polyether polycarbonate diol (A) and the diol of the present invention, other polyols, and an excess polyisocyanate compound are mixed in advance with the polyisocyanate compound/(polyether polycarbonate diol (A) and the diol of the present invention and polyol other than polyol) is reacted at a reaction equivalent ratio of more than 1 to 10.0 or less to produce a prepolymer having an isocyanate group at the molecular chain end, and then a chain extender is added to the prepolymer to produce a polyurethane elastomer. How to manufacture.
(b) a polyisocyanate compound, excess polyether polycarbonate diol (A), the diol of the present invention and other polyols are mixed in advance with the polyisocyanate compound/(polyether polycarbonate diol (A) and the diol of the present invention); A polyol other than polyol) is reacted at a reaction equivalent ratio of 0.1 or more to less than 1.0 to produce a prepolymer having a hydroxyl group at the molecular chain end, and then a polyisocyanate compound having an isocyanate group at the end as a chain extender is added to this. to produce a polyurethane elastomer.

The two-step method can be carried out without solvent or in the presence of solvent.
Polyurethane elastomer production by the two-step method can be carried out by any one of the methods (1) to (3) described below.
(1) Without using a solvent, the polyisocyanate compound and the polyether polycarbonate diol (A), the diol of the present invention and other polyols are directly reacted to synthesize a prepolymer, and the prepolymer is used as it is for the chain extension reaction. .
(2) A prepolymer is synthesized by the method of (1), then dissolved in a solvent and used for subsequent chain extension reaction.
(3) Using a solvent from the beginning, the polyisocyanate compound and the polyether polycarbonate diol (A), the diol of the present invention and other polyols are reacted, and then the chain extension reaction is carried out.

In the case of method (1), in the chain extension reaction, the polyurethane elastomer is allowed to coexist with the solvent by a method such as dissolving the chain extender in the solvent or dissolving the prepolymer and the chain extender in the solvent at the same time. Getting it in shape is important.
The amount of the polyisocyanate compound used in the two-step method (a) is not particularly limited, but the total number of hydroxyl groups of the polyether polycarbonate diol (A), the diol of the present invention, and other polyols is set to 1 equivalent. When the number of isocyanate groups in the It is in the range of 5.0 equivalents, more preferably 3.0 equivalents.

If the amount of the polyisocyanate compound used is too large, the excess isocyanate groups tend to cause side reactions, making it difficult to achieve the desired physical properties of the polyurethane elastomer. Strength and thermal stability may be reduced.
The amount of the chain extender used is not particularly limited, but the lower limit is preferably 0.1 equivalents, more preferably 0.5 equivalents, and still more preferably 0 equivalents per equivalent of the number of isocyanate groups contained in the prepolymer. 8 equivalents, and the upper limit is preferably 5.0 equivalents, more preferably 3.0 equivalents, and still more preferably 2.0 equivalents.

For the purpose of adjusting the molecular weight, monofunctional organic amines and alcohols may coexist during the chain extension reaction.
In the two-step method (b), the amount of the polyisocyanate compound to be used when preparing the prepolymer having a hydroxyl group at the end is not particularly limited, but the polyether polycarbonate diol (A) and the diol of the present invention As the number of isocyanate groups when the total number of hydroxyl groups of the other polyol is 1 equivalent, the lower limit is preferably 0.1 equivalent, more preferably 0.5 equivalent, still more preferably 0.7 equivalent, and the upper limit is preferably 0.99 equivalents, more preferably 0.98 equivalents, still more preferably 0.97 equivalents.

If the amount of the polyisocyanate compound used is too small, the subsequent chain elongation reaction takes a long time to obtain the desired molecular weight, and production efficiency tends to decrease. Flexibility may be reduced, and handling may be poor, resulting in poor productivity.
The amount of the chain extender used is not particularly limited. The lower limit is preferably 0.7 equivalent, more preferably 0.8 equivalent, still more preferably 0.9 equivalent, and the upper limit is preferably less than 1.0 equivalent, More preferably 0.99 equivalents, still more preferably 0.98 equivalents.

For the purpose of adjusting the molecular weight, monofunctional organic amines and alcohols may coexist during the chain extension reaction.
The chain extension reaction is usually carried out at 0° C. to 250° C., but this temperature varies depending on the amount of solvent, reactivity of raw materials used, reaction equipment, etc., and is not particularly limited. If the temperature is too low, the progress of the reaction slows down, and the production time may be lengthened due to the low solubility of the raw materials and polymer. . The chain extension reaction may be performed under reduced pressure while defoaming.

Moreover, a catalyst, a stabilizer, etc. can also be added to a chain extension reaction as needed.
Examples of the catalyst include compounds such as triethylamine, tributylamine, dibutyltin dilaurate, stannous octoate, acetic acid, phosphoric acid, sulfuric acid, hydrochloric acid, and sulfonic acid. They may be used together. Examples of stabilizers include 2,6-dibutyl-4-methylphenol, distearylthiodipropionate, N,N'-di-2-naphthyl-1,4-phenylenediamine, tris(dinonylphenyl)phosphite and the like. and may be used singly or in combination of two or more. If the chain extender is highly reactive such as a short-chain aliphatic amine, the reaction may be carried out without adding a catalyst.
A reaction inhibitor such as tris(2-ethylhexyl) phosphite can also be used.

<Additive>
Various additives such as heat stabilizers, light stabilizers, colorants, fillers, stabilizers, UV absorbers, antioxidants, anti-adhesives, flame retardants, anti-aging agents, and inorganic fillers may be added to the polyurethane elastomer of the present invention. Additives can be added and mixed as long as the properties of the polyurethane elastomer of the present invention are not impaired.

Compounds that can be used as heat stabilizers include phosphoric acid, aliphatic, aromatic or alkyl-substituted aromatic esters of phosphorous acid, hypophosphorous acid derivatives, phenylphosphonic acid, phenylphosphinic acid, diphenylphosphonic acid, polyphosphonates, dialkyl Phosphorus compounds such as pentaerythritol diphosphite and dialkylbisphenol A diphosphite; phenol derivatives, especially hindered phenol compounds; Compounds containing sulfur; tin-based compounds such as tin malate, dibutyltin monoxide, and the like can be used.

Specific examples of hindered phenol compounds include "Irganox1010" (trade name: manufactured by BASF Japan Ltd.), "Irganox1520" (trade name: manufactured by BASF Japan Ltd.), "Irganox245" (trade name: manufactured by BASF Japan Ltd.). ) and the like.
Phosphorus compounds include "PEP-36", "PEP-24G", "HP-10" (all trade names: manufactured by ADEKA Corporation), "Irgafos 168" (manufactured by BASF Japan Ltd.), etc. is mentioned.

Specific examples of sulfur-containing compounds include thioether compounds such as dilaurylthiopropionate (DLTP) and distearylthiopropionate (DSTP).
Examples of light stabilizers include benzotriazole-based compounds and benzophenone-based compounds. ”, “SANOL LS-765” (manufactured by Sankyo Co., Ltd.) and the like can be used.

Examples of ultraviolet absorbers include "TINUVIN328" and "TINUVIN234" (manufactured by Ciba Specialty Chemicals Co., Ltd.).

Colorants include dyes such as direct dyes, acid dyes, basic dyes and metal complex dyes; inorganic pigments such as carbon black, titanium oxide, zinc oxide, iron oxide and mica; Organic pigments such as anthraquinone-based, thioindigo-based, dioxazone-based, and phthalocyanine-based pigments can be used.

Examples of inorganic fillers include short glass fibers, carbon fibers, alumina, talc, graphite, melamine, and clay.

Examples of flame retardants include additive and reactive flame retardants such as phosphorous and halogen containing organic compounds, bromine or chlorine containing organic compounds, ammonium polyphosphate, aluminum hydroxide, antimony oxide and the like.

These additives may be used alone, or two or more of them may be used in any combination and ratio.

Regarding the amount of these additives added, the lower limit is preferably 0.01% by weight, more preferably 0.05% by weight, still more preferably 0.1% by weight, and the upper limit is preferably 10% by weight, more preferably 5% by weight, and even more preferably 1% by weight. If the amount of the additive added is too small, the effect of the addition cannot be sufficiently obtained, and if it is too large, the polyurethane elastomer may precipitate or become cloudy.

<Molecular weight>
The molecular weight of the polyurethane elastomer of the present invention is appropriately adjusted according to its use, and is not particularly limited, but is preferably 50,000 to 500,000 as a polystyrene equivalent weight average molecular weight (Mw) measured by GPC. It is more preferably 100,000 to 300,000. If Mw is less than the above lower limit, sufficient strength and hardness may not be obtained.

<Application>
INDUSTRIAL APPLICABILITY The polyurethane elastomer of the present invention is excellent in transparency, flexibility and durability, has good heat resistance and abrasion resistance, and is excellent in workability, so that it can be used for various purposes.

For example, the polyurethane elastomers of the present invention can be used in cast polyurethane elastomers. Specific applications include rolling rolls, paper manufacturing rolls, office equipment, rolls such as pretension rolls, solid tires for forklifts, automobile vehicle nutrams, trolleys, trucks, casters, etc. Industrial products include conveyor belt idlers and guides. Rolls, pulleys, steel pipe linings, ore rubber screens, gears, connection rings, liners, pump impellers, cyclone cones, cyclone liners, etc. It can also be used for OA equipment belts, paper feed rolls, copying cleaning blades, snow plows, toothed belts, surf rollers and the like.

The polyurethane elastomer of the present invention also finds application as a thermoplastic elastomer. That is, by molding the thermoplastic polyurethane elastomer of the present invention, a molded article having excellent stretchability can be obtained. The method of molding the thermoplastic polyurethane elastomer of the present invention is not particularly limited, and various molding methods commonly used for thermoplastic polymers can be used. For example, any molding method such as injection molding, extrusion molding, press molding, blow molding, calender molding, casting molding, roll processing, etc. can be adopted, and resin plates, films, sheets, tubes, hoses, belts, rolls, etc. can be used. , synthetic leather, shoe soles, automobile parts, escalator handrails, road sign members, textiles, etc.

More specific applications of the thermoplastic polyurethane elastomer of the present invention include, for example, pneumatic equipment used in the food and medical fields, coating equipment, analytical equipment, physics and chemistry equipment, metering pumps, water treatment equipment, industrial robots, and the like. Can be used for tubes and hoses, spiral tubes, fire hoses, etc. In addition, it is used as a belt such as a round belt, a V belt, a flat belt, etc. in various transmission mechanisms, spinning machines, packing machines, printing machines, and the like. It can also be used for heel tops and soles of footwear, couplings, packings, pole joints, bushes, gears, machine parts such as rolls, sporting goods, leisure goods, watch belts and the like. Automobile parts include oil stoppers, gearboxes, spacers, chassis parts, interior parts, and tire chain substitutes. Also, it can be used for films such as keyboard films and films for automobiles, curled cords, cable sheaths, bellows, conveyor belts, flexible containers, binders, synthetic leathers, dipping products, adhesives and the like.

The polyurethane elastomers of the present invention can also be foamed polyurethane elastomers or polyurethane foams. Examples of methods for foaming or forming a polyurethane elastomer include chemical foaming using water and mechanical foaming such as mechanical flossing. Similarly, slabs, flexible foams obtained by molding, and the like can be mentioned.
Specific uses of foamed polyurethane elastomers or polyurethane foams include thermal insulation and vibration-proof materials for electronic devices and construction, automobile seats, automobile ceiling cushions, bedding such as mattresses, insoles, midsoles, shoe soles, and the like.

EXAMPLES The present invention will be described in more detail below with reference to examples , reference examples, and comparative examples, but the present invention is not limited to these examples as long as it does not exceed the scope of the invention.

〔Evaluation method〕
The evaluation methods for the polycarbonate diols and polyurethane elastomers obtained in the following Examples , Reference Examples and Comparative Examples and the polyalkylene ether glycol used are as follows.

[Evaluation method for polyether polycarbonate diol, polycarbonate diol, and polyoxyalkylene glycol]
<Hydroxyl value/number average molecular weight>
According to JIS K1557-1, hydroxyl values of polycarbonate diol, polyether polycarbonate diol, and polyoxyalkylene glycol were measured by a method using an acetylation reagent.
Also, from the hydroxyl value, the number average molecular weight (Mn) was determined by the following formula (I).
Number average molecular weight = 2 × 56.1 / (hydroxyl value × 10 ^-3 ) (I)

<Mole ratio of repeating unit (B) to repeating unit (C)>
Polycarbonate diol was dissolved in CDCl ₃ , 400 MHz ¹ H-NMR (AL-400 manufactured by JEOL Ltd.) was measured, and from the signal position of each component, the molar ratio of repeating unit (B) and repeating unit (C) ( C)/(B) was determined.

[Method for evaluating polyurethane elastomer]
<Molecular weight>
A polyurethane elastomer was dissolved in dimethylacetamide to prepare a dimethylacetamide solution having a concentration of 0.14% by weight. Using a GPC apparatus [manufactured by Tosoh Corporation, product name "HLC-8220" (column: TskgelGMH-XL, 2 columns)], the dimethylacetamide solution is injected, and the weight average molecular weight (Mw ) was measured.

<Tensile test>
According to JIS K6301 (2010), sheet-like polyurethane elastomers with a thickness of 1 mm obtained in Examples , Reference Examples and Comparative Examples were cut into strips with a width of 10 mm and a length of 100 mm. Orientec Co., Ltd., product name "Tensilon UTM-III-100"), the distance between chucks is 50 mm, the tensile speed is 500 mm / min, the temperature is 23 ° C., the tensile test is performed at a relative humidity of 55%. Stress at 100% elongation: 100% modulus was measured. Those having a 100% modulus of 5 MPa or more have a high elastic modulus. Also, the elongation and strength when the test piece was broken were measured. The higher the elongation and strength, the better the flexibility and mechanical strength.

<Evaluation of Durability: Resistance to Oleic Acid>
A 3 cm x 3 cm test piece was cut out from the 2 mm thick polyurethane elastomer sheets obtained in Examples , Reference Examples and Comparative Examples, and placed in a 50 ml glass bottle containing 10 ml of oleic acid as a test solvent. After standing at 80° C. for 18 hours, the state was visually observed and evaluated as follows.
◯: The shape of the sheet is maintained.
Δ: The sheet is partially swollen.
x: The sheet is damaged due to swelling.

<Evaluation of transparency>
A 3 cm×3 cm test piece was cut out from the 2 mm thick polyurethane elastomer sheets obtained in Examples , Reference Examples, and Comparative Examples, and visually observed to determine transparency as follows.
◯: The sheet as a whole is transparent Δ: The sheet is partially cloudy.
x: The sheet is clouded as a whole.

[Production and Evaluation of Polyether Polycarbonate Diol]
[Synthesis Example 1]
A 2 L glass separable flask equipped with a stirrer, a distillate trap, a pressure regulator, a distillation column with a 30 mm diameter regular packing, and a fractionator was filled with polytetramethylene ether glycol PTMG#250 (number average molecular weight: 247) manufactured by Mitsubishi Chemical Corporation. 423 g (1.7 mol) of ethylene carbonate (EC), 176 g (2.0 mol) of ethylene carbonate (EC), and 62 mg (0.28 mmol) of magnesium (II) acetylacetonate were added, and the atmosphere was replaced with nitrogen gas. While stirring, the internal temperature was raised to 150° C. to heat and dissolve the contents. Then, after reacting at normal pressure for 1 hour, the pressure was lowered to 6 kPa, and the reaction was carried out for 12 hours while removing ethylene glycol and ethylene carbonate out of the system with an azeotropic composition. The reaction was then carried out at 150° C. to 170° C. while reducing the pressure to 1 kPa over 12 hours. A number average molecular weight of about 1000 was confirmed by ¹ H-NMR, and a polyether polycarbonate diol-containing composition was obtained.
Thereafter, 0.4 mL (0.4 mmol) of 8.5% aqueous phosphoric acid solution was added to the polyether polycarbonate diol-containing composition to deactivate the catalyst. After that, the distillation column was removed, and residual monomers were removed at 0.5 kPa and 170° C. to obtain a polyether polycarbonate diol-containing composition.

The obtained polyether polycarbonate diol-containing composition was fed to a thin film distillation apparatus at a flow rate of 20 g/min, and subjected to thin film distillation (temperature: 210°C, pressure: 53 Pa) to obtain a polyether polycarbonate diol. As the thin-film distillation apparatus, a molecular distillation apparatus MS-300 special type manufactured by Shibata Scientific Co., Ltd. with an internal condenser and a jacket having a diameter of 50 mm, a height of 200 mm and an area of 0.0314 m ² was used.
The polyether polycarbonate diol produced in Synthesis Example 1 is referred to as "PEPCD1".
Table 1 shows the evaluation results of the properties and physical properties of this PEPCD1.

[Polycarbonate Diol]
As the polycarbonate diol, 1,6-hexanediol homotype polycarbonate diol "T6001" manufactured by Asahi Kasei Corporation, which is a commercially available polycarbonate diol having a hydroxyl value-based number average molecular weight (Mn) of 1000 (hereinafter referred to as "T6001"). described.) was used.

[Polyalkylene ether glycol]
As the polyalkylene ether glycol, Mitsubishi Chemical Co., Ltd. polytetramethylene ether glycol "PTMG#1000" (hereinafter, "#1000 ) was used.

[Production and Evaluation of Polyurethane Elastomer]
[ Reference example 1]
<Production of Polyurethane Elastomer>
PEPCD1: 36.5 g, #1000: 36.5 g, and 4,4'-diphenylmethane diisocyanate (hereinafter "MDI ): 40.4 g, and tris(2-ethylhexyl) phosphite: 0.9 g as an inhibitor to the urethanization reaction. Then, the reactor was covered and reacted for about 90 minutes while being stirred and mixed at 2000 rpm under reduced pressure conditions (10 torr or less). After the reaction, 6.98 g of 1,4BD was gradually added to the reactor after the heat generation subsided, and after stirring for 2 minutes, the lid of the reactor was removed. A fluororesin sheet (fluorine tape Nitoflon 900, thickness 0.1mm, manufactured by Nitto Denko Co., Ltd.) is pasted on the glass plate, and a silicon mold (dimensions: 10cm x 10cm, thickness 2mm) is placed on it. did. The reaction solution was poured into this silicon mold, and the top of the silicon mold was covered with a glass plate having a fluororesin sheet attached to the lower side. A 4.5 kg weight was then placed on the glass plate on top of the mold and inserted into the dryer. It was dried by heating (110° C.×1 hour) in the dryer in a nitrogen atmosphere.

<Melt molding>
The resulting polyurethane elastomer (dimensions 10 cm x 10 cm, thickness 2 mm) was removed from the silicone mold after standing overnight.
A fluororesin sheet and a mold for melt molding were placed in this order on the plate of a heating press (manufactured by Toyo Seiki Seisakusho, product name "Mini Test Press") preheated to 180°C. Either of two molds of 4 cm×4 cm×2 mm in thickness and 10 cm×5 cm×1 mm in thickness was used as the mold for melt molding depending on the use such as the evaluation of physical properties. A polyurethane elastomer was placed in a mold, which was then covered with a fluororesin sheet. A plate of a hot press was used to melt the polyurethane laster (pressure: 1 MPa x temperature: 180°C x time: 5 minutes). After melting, the pressure setting of the heating press was gradually increased to a maximum of 10 MPa for 5 minutes for heating and molding. After that, the pressure of the heating press is lowered, the polyurethane elastomer molded product is removed, and it is placed in a cooling press (manufactured by Toyo Seiki Seisakusho, product name "Mini Test Press") that has been chilled by running cooling water in advance to rapidly cool it. (pressure 10 MPa×time 2 minutes) to obtain a sheet-like polyurethane elastomer molded article. Table 2 shows the evaluation results of the physical properties of the polyurethane elastomer molded article.

[Example 2, Comparative Examples 1 to 4]
A sheet-like polyurethane elastomer molded article was obtained in the same manner as in Reference Example 1 except that the amount of raw material used was changed to that shown in Table 2, and the evaluation was performed in the same manner. Table 2 shows the evaluation results of the physical properties of the polyurethane elastomer molded article.

Table 2 reveals the following.
Example 2 , in which the polyether polycarbonate diol (A) and PTMG and/or PCD are used in combination, is excellent in transparency, flexibility, mechanical strength and durability.
On the other hand, Comparative Example 1 using only the polyether polycarbonate diol (A) and not using PTMG and/or PCD in combination, and Comparative Examples 2 and 3 using only PTMG or PCD showed excellent flexibility and mechanical strength. Comparative Examples 1 and 2 do not have sufficient durability.
Even if PTMG and PCD are used in combination, in Comparative Example 4 in which the polyether polycarbonate diol (A) is not used, the compatibility when the polyol is mixed is poor, resulting in poor flexibility, mechanical strength, and transparency.

Claims (13)

A structural unit derived from a compound having multiple isocyanate groups, a structural unit derived from at least one compound selected from the group consisting of polyols and polyamines, and a polyether carbonate diol represented by the following formula (A): A polyurethane elastomer comprising a structural unit and a structural unit derived from a polycarbonate diol having at least a repeating unit represented by the following formula (B) and a repeating unit represented by the following formula (C).

(In the above formula (A), R ¹ represents a divalent hydrocarbon group having 3 to 10 carbon atoms, n is an integer of 2 to 30, and m is an integer of 1 to 20. The formula ( In A), a plurality of R ¹ may be the same or different.)

(In formula (B) above, R ² represents a divalent hydrocarbon group having 2 to 20 carbon atoms, p is an integer of 3 to 50, and R ³ is different from R ² in formula (C) above. represents a divalent hydrocarbon group having 3 to 20 carbon atoms, or represents a divalent hydrocarbon group having 3 to 20 carbon atoms containing an alicyclic structure or a heterocyclic structure, q is 0 It is an integer from ~50 .) 2. The polyurethane elastomer according to claim 1, wherein the ratio of the structural units derived from the polyether polycarbonate diol to the structural units derived from the polycarbonate diol is 10% by weight to 90% by weight. 3. The polyurethane elastomer according to claim 1, wherein R ¹ in formula (A) is an n-butylene group and/or a 2-methylbutylene group. 4. The polyurethane elastomer according to any one of claims 1 to 3, wherein the molar ratio of the repeating unit represented by the formula (C) to the repeating unit represented by the formula (B) is 0.03-10. 5. The polyurethane elastomer according to any one of claims 1 to 4, wherein R ² in the formula (B) is a divalent hydrocarbon group having 3 to 6 carbon atoms. 6. The polyurethane elastomer according to any one of claims 1 to 5, wherein R ³ in formula (C) is a divalent hydrocarbon group having 4 to 12 carbon atoms. The structural unit derived from the formula (C) consists of neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol and 2-methyl-1,4-butanediol. 6. The polyurethane elastomer according to any one of claims 1 to 5, which is a structural unit derived from at least one selected from the group. 6. Any one of claims 1 to 5, wherein the structural unit derived from formula (C) is a structural unit derived from at least one selected from the group consisting of isosorbide, isomannide, isoidide, and 1,4-cyclohexanedimethanol. 1. The polyurethane elastomer according to claim 1. 9. The polyurethane elastomer according to any one of claims 1 to 8 , wherein the compound having a plurality of isocyanate groups is an aromatic diisocyanate compound. 10. The polyurethane elastomer according to claim 9 , wherein the aromatic diisocyanate compound is at least one selected from the group consisting of 4,4' -diphenylmethane diisocyanate, toluene diisocyanate and xylylene diisocyanate. At least one compound selected from the group consisting of polyols and polyamines is at least one compound selected from the group consisting of ethylene glycol, 1,4-butanediol and 1,6-hexanediol. 11. The polyurethane elastomer according to any one of 1 to 10 . 12. The polyurethane elastomer according to any one of claims 1 to 11 , wherein said polyurethane elastomer is a thermoplastic elastomer. 13. A method for producing a polyurethane elastomer according to any one of claims 1 to 12 , wherein at least one compound selected from the group consisting of the compound having a plurality of isocyanate groups, the polyol and the polyamine, A method for producing a polyurethane elastomer in which an addition polymerization reaction of a polycarbonate diol is carried out without a solvent.