JP2020084152A - Polyurethane elastomer and method for producing the same - Google Patents

Abstract

To provide a polyurethane elastomer excellent in flexibility, durability and stress relaxation.SOLUTION: The polyurethane elastomer is obtained by reacting a compound having a plurality of isocyanate groups, at least one chain extender selected from the group consisting of polyols and polyamines, a polycarbonate diol having a repeating unit represented by formula (A) and a repeating unit represented by formula (B), and a polyalkylene ether glycol. (In the formula (A), p is an integer of 2-20, and n is an integer of 3-50. In the formula (B), m is an integer of 1-50, and Ris a C3-20 alkylene group containing a branched chain.)SELECTED DRAWING: None

Description

The present invention relates to a polyurethane elastomer having excellent flexibility and durability and a method for producing the polyurethane elastomer.

Polyurethane elastomers include a thermoplastic polyurethane elastomer (TPU) that softens when heated and then hardens when cooled, and a thermosetting polyurethane elastomer (TSU) that hardens by heating, but both have excellent elasticity and mechanical strength. , Low temperature characteristics, abrasion resistance, weather resistance, oil resistance, excellent workability, and easy to process into various shapes. Therefore, industrial parts such as rolls and casters, automobiles such as solid tires and belts. In addition to parts, paper feed rolls, copier rolls, and other OA equipment parts, they are widely used in 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. Has proposed a two-component thermosetting polyurethane elastomer having improved mechanical strength (tensile strength, elongation), low compression strain, low impact resilience, water resistance and the like.

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

Patent Document 3 proposes a polyurethane foam in which a polycarbonate diol and a polyether polyol are used in combination as a polyol to be reacted with polyisocyanate, and as the polycarbonate diol, 3-methyl-1,5-pentanediol and 1,6- Those using hexamethylene diol as a raw material are described.

Patent Document 4 describes that the polyurethane using the polycarbonate diol used in the present invention is excellent in strength, hardness, heat resistance, abrasion resistance and workability.

JP, 2013-163778, A JP, 2005-081278, A JP, 2016-044238, A JP, 2017-222854, A

With respect to the polyurethane elastomer, further improvement in flexibility and durability is desired in its application, but in the conventional polyurethane elastomers proposed in Patent Documents 1 and 2, compatibility of flexibility and durability is achieved. However, the stress relaxation property was poor.
That is, in the conventional polyurethane elastomer, the physical properties of the obtained polyurethane elastomer molded product were insufficient in the solvent-free system due to the effect of mass transfer due to the low compatibility of the polyol during the urethanization reaction. For example, in the polyurethane elastomer synthesized by the method proposed in Patent Document 1, since the compatibility of the polyols is poor, a polycarbonate diol is previously reacted with an isocyanate compound to form a prepolymer, and then polytetramethylene glycol or the like is used. It was necessary to mix with a curing agent, and the resulting polyurethane elastomer had an insufficient balance of physical properties of durability and flexibility.

Patent Document 3 describes a combined use of a polycarbonate diol having a repeating unit (A) and a repeating unit (B) described below used in the present invention and a polyalkylene ether glycol. However, Patent Document 3 discloses a foamed polyurethane foam. There is no description suggesting that the combined use of these improves the flexibility, durability and stress relaxation as a polyurethane elastomer.

Patent Document 4 does not disclose a polyurethane elastomer in which a polycarbonate diol and a polyalkylene ether glycol are used in combination.

An object of the present invention is to provide a polyurethane elastomer having excellent flexibility, durability and stress relaxation.

As a result of earnest studies to solve the above problems, the present inventor can solve the above problems by producing a polyurethane elastomer by using a specific polycarbonate diol and a polyalkylene ether glycol as a polyol raw material in combination. I found that I could do it.

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

[1] A compound having a plurality of isocyanate groups, at least one chain extender selected from the group consisting of polyols and polyamines, a repeating unit represented by the following formula (A), and a repeating unit represented by the following formula (B). A polyurethane elastomer obtained by reacting a polycarbonate diol having a repeating unit and a polyalkylene ether glycol.

(In the formula (A), p is an integer of 2 to 20 and n is an integer of 3 to 50. In the formula (B), m is an integer of 1 to 50 and R ¹ is a branched chain. Is an alkylene group having 3 to 20 carbon atoms including.

[2] The polyurethane elastomer according to [1], wherein the ratio of the polycarbonate diol to the total of the polycarbonate diol and the polyalkylene ether glycol is 25 to 90% by weight.

[3] The molar ratio of the repeating unit represented by the formula (B) to the repeating unit represented by the formula (A) contained in the polycarbonate diol is 0.03 to 10 [1] or [2]. The polyurethane elastomer according to.

[4] The polyurethane elastomer according to any one of [1] to [3], wherein p in the formula (A) is an integer of 4 to 6.

[5] The ratio of the number of carbon atoms of the branched chain in R ¹ of the formula (B) is 0.05 to 0.5 with respect to the total number of carbon atoms in R ¹ , [1] to [4]. Polyurethane elastomer.

[6] The repeating unit represented by the formula (B) contained in the polycarbonate diol includes neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol and 2- The polyurethane elastomer according to any one of [1] to [5], which is derived from at least one selected from the group consisting of methyl-1,4-butanediol.

[7] The polyurethane elastomer according to any one of [1] to [6], wherein the polyalkylene ether glycol has a molecular weight of 200 to 5,000 based on a hydroxyl value.

[8] The polyalkylene ether glycol is polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, copolymerization polytetramethylene ether glycol of 3-methyltetrahydrofuran and tetrahydrofuran, copolymerization polyether polyol of neopentyl glycol and tetrahydrofuran, ethylene oxide The polyurethane elastomer according to any one of [1] to [7], which is at least one selected from the group consisting of a copolymerized polyether polyol of propylene oxide and tetrahydrofuran, and a copolymerized polyether glycol of propylene oxide and tetrahydrofuran.

[9] The difference between the hydrogen bond term δH of the Hansen's solubility parameter of the polycarbonate diol and the hydrogen bond term δH of the Hansen's solubility parameter of the polyalkylene ether glycol is 3 or less, and the polycarbonate diol and the polyalkylene ether glycol are dissolved spheres. The polyurethane elastomer according to any one of [1] to [8], each having a radius R of 8 or more.

[10] The polyurethane elastomer according to any one of [1] to [9], wherein the compound having a plurality of isocyanate groups is an aromatic diisocyanate compound.

[11] The polyurethane elastomer according to [10], wherein the aromatic diisocyanate compound is at least one selected from the group consisting of 1,4-diphenylmethane diisocyanate, toluene diisocyanate and xylylene diisocyanate.

[12] The polyurethane according to any one of [1] to [11], wherein the chain extender is at least one selected from the group consisting of ethylene glycol, 1,4-butanediol and 1,6-hexanediol. Elastomer.

[13] The polyurethane elastomer according to any one of [1] to [12], wherein the polyurethane elastomer is a thermoplastic elastomer.

[14] A method for producing the polyurethane elastomer according to any one of [1] to [13], comprising the compound having a plurality of isocyanate groups, the chain extender, the polycarbonate diol, and the polyalkylene ether glycol. A method for producing a polyurethane elastomer, wherein the reaction is carried out without using a solvent.

According to the present invention, a polyurethane elastomer having excellent flexibility and durability is provided.
In the present invention, "durability" means chemical resistance, weather resistance, and resistance performance against various other chemical and physical influences.

Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to the following embodiments, and various modifications can be carried out within the scope of the gist thereof.

[Polyurethane elastomer]
The polyurethane elastomer of the present invention is a compound having a plurality of isocyanate groups (hereinafter sometimes referred to as “polyisocyanate compound”), at least one chain extender selected from the group consisting of polyols and polyamines, and the following formula: A repeating unit represented by (A) (hereinafter sometimes referred to as "repeating unit (A)") and a repeating unit represented by the following formula (B) (hereinafter referred to as "repeating unit (B)") In some cases) and a polyalkylene ether glycol.

(In the formula (A), p is an integer of 2 to 20 and n is an integer of 3 to 50. In the formula (B), m is an integer of 1 to 50 and R ¹ is a branched chain. Is an alkylene group having 3 to 20 carbon atoms including.

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

For example, tetramethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate and dimerisocyanate obtained by converting the carboxyl group of dimer acid into an isocyanate group. Aliphatic diisocyanate compound; 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 can be used. These may be used alone or in combination of two or more.

Among these, aromatic polyisocyanate compounds are preferable because of their reactivity with polyols and high curability of the resulting polyurethane elastomer, and 4,4′-diphenylmethane is particularly preferable because they are industrially inexpensive and available in large amounts. Diisocyanate (hereinafter sometimes referred to as “MDI”), toluene diisocyanate (TDI), and xylylene diisocyanate are preferable.

<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 an isocyanate group in the case of producing a prepolymer having an isocyanate group described later, and a polyol And polyamines.

Specific examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol and 1,9-nonanediol. , Linear diols such as 1,10-decanediol and 1,12-dodecanediol; 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 diols having branched chains 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 an aromatic group such as 1,4-dihydroxyethylbenzene and 4,4′-methylenebis(hydroxyethylbenzene); polyols such as glycerin, trimethylolpropane and pentaerythritol; N-methylethanolamine, N-ethylethanol Hydroxyamines such as amines; 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; and the like can be mentioned.

These chain extenders may be used alone or in combination of two or more.

Among these, 1,4-butane is excellent in flexibility and elastic recovery due to excellent phase separation between the soft segment and the hard segment of the polyurethane elastomer obtained, and in that it is industrially available in large quantities at low cost. Diol, 1,5-pentanediol and 1,6-hexanediol are preferred.

<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”) includes the repeating unit (A) represented by the following formula (A) and the following formula (B). ) Having the repeating unit (B).

(In the formula (A), p is an integer of 2 to 20 and n is an integer of 3 to 50. In the formula (B), m is an integer of 1 to 50 and R ¹ is a branched chain. Is an alkylene group having 3 to 20 carbon atoms including.

By using the polycarbonate diol having the repeating unit (A) and the repeating unit (B), it is possible to produce a polyurethane elastomer having excellent balance of flexibility, durability and stress relaxation.

In the repeating unit (A), p is preferably 3 to 12, more preferably 3 to 6, and particularly preferably 4 or 6, and the repeating unit (A) is 1,4-butanediol (p=4), 1 ,5-pentanediol (p=5) and 1,6-hexanediol (p=6) are preferable, from the viewpoints of industrial availability and excellent physical properties of the resulting polyurethane elastomer, in particular - _{(CH 2) P} - is n- butylene, n- hexylene group is preferable.

The repeating unit (A) can be introduced into the polycarbonate diol by using a linear aliphatic dihydroxy compound having 2 to 20 carbon atoms as a raw material diol of the polycarbonate diol.

In the repeating unit (A), when n is less than 3, the flexibility of the obtained polyurethane elastomer tends to be poor, and when it exceeds 50, the viscosity of the obtained polycarbonate diol tends to be high and the handleability tends to be poor. Therefore, n is 3 to 50, preferably 3 to 40, and more preferably 5 to 30.

On the other hand, in the repeating unit (B), R ¹ is an alkylene group having a branched chain and having 3 to 20 carbon atoms, and from the viewpoint of compatibility with the polyalkylene polyol, preferably, the number of carbon atoms of the branched chain in R ¹ is A branched alkylene group having a ratio of 0.05 to 0.5 with respect to the total number of carbon atoms of R ¹ . Such branched alkylene groups include those derived from neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol and 2-methyl-1,4-butanediol. Can be mentioned.

In the repeating unit (B), when m is less than 1, the compatibility with the polyalkylene polyol tends to be low, and the flexibility and durability of the resulting polyurethane elastomer tend to be poor, and when it exceeds 50, the abrasion resistance tends to be poor. is there. Therefore, m is 1 to 50, preferably 2 to 50, more preferably 2 to 40, and further preferably 2 to 30.

The polycarbonate diol of the present invention may contain only one type of repeating unit (A) or may contain two or more types thereof. Further, the repeating unit (B) may contain only one kind or two or more kinds. Further, repeating units other than the repeating unit (A) and the repeating unit (B) may be contained in, for example, 5.0 mol% or less in all the repeating units, as long as the effects of the present invention are not impaired.

The molar ratio of the structural unit (B) to the structural unit (A) contained in the polycarbonate diol of the present invention (structural unit (B)/structural unit (A), sometimes referred to as “molar ratio (B)/(A)”). Is preferably 0.03 to 10, particularly preferably 0.05 to 4, and particularly preferably 0.10 to 1.00. When the amount of the structural unit (A) is larger and the amount of the structural unit (B) is smaller than the above range, the compatibility with other polyols tends to decrease, and conversely, the structural unit (A) is small and the structural unit (B) is When the amount is large, the flexibility of the obtained polyurethane elastomer tends to be lowered, especially the flexibility at low temperature and the chemical resistance.
The molar ratio (B)/(A) of the polycarbonate diol is measured by the method described in the section of Examples below.

The polycarbonate diol of the present invention is a linear aliphatic dihydroxy compound having 2 to 20 carbon atoms, preferably 4 to 6 carbon atoms for introducing the structural unit (A), specifically 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, One or two kinds of 1,14-tetradecanediol, 1,16-hexadecanediol, 1,18-octadecanediol, preferably 1,4-butanediol, 1,5-pentadiol, 1,6-hexanediol and the like. In addition to the above, a branched aliphatic dihydroxy compound having 3 to 20 carbon atoms for introducing the structural unit (B), preferably neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3- One or more kinds of propanediol, 2-methyl-1,4-butanediol and the like are used as a raw material dihydroxy compound so as to have the above-mentioned suitable structural unit (B)/structural unit (A) molar ratio. Can be produced by polymerizing the dihydroxy compound and the polycarbonate compound according to a conventional method in the presence of a catalyst.

The carbonate compound that can be used for producing the polycarbonate diol of the present invention is not limited as long as the effects of the present invention are not impaired, and examples thereof include dialkyl carbonate, diaryl carbonate, and alkylene carbonate. These may be one kind or plural kinds. Of these, diaryl carbonate is preferable from the viewpoint of reactivity.

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

In the case of producing a polycarbonate diol, a transesterification catalyst can be used if necessary to accelerate the polymerization.
As the transesterification catalyst, any compound generally known to have transesterification ability can be used without limitation.

Examples of transesterification catalysts include long-periodic periodic tables (hereinafter simply referred to as "periodic table") such as lithium, sodium, potassium, rubidium, and cesium, and compounds of Group 1 metals (excluding hydrogen); Compounds of Group 2 metals of the periodic table such as magnesium, calcium, strontium, 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; compounds of the periodic table such as cobalt Compounds of Group 9 metals; compounds of Group 12 metals of the periodic table such as zinc; compounds of Group 13 metals of the periodic table such as aluminum; compounds of Group 14 metals of the periodic table such as germanium, tin, lead; antimony, bismuth, etc. Compounds of Group 15 metals of the periodic table of lanthanides; compounds of lanthanide-based metals such as lanthanum, cerium, europium, and ytterbium. Among these, from the viewpoint of increasing the transesterification reaction rate, compounds of Group 1 metals (excluding hydrogen) of the periodic table, compounds of Group 2 metals of the periodic table, compounds of Group 4 metals of the periodic table, and Group 5 of the periodic table. A compound of a group metal, a compound of a group 9 metal of the periodic table, a compound of a group 12 metal of the periodic table, a compound of a group 13 metal of the periodic table, a compound of a group 14 metal of the periodic table is preferable, and a group 1 metal of the periodic table ( Compounds other than hydrogen) and compounds of Group 2 metals of the periodic table are more preferable, and compounds of Group 2 metals of the periodic table are further preferable. Among the compounds of Group 1 metals (excluding hydrogen) of the periodic table, compounds of lithium, potassium and sodium are preferable, compounds of lithium and sodium are more preferable, and compounds of sodium are further preferable. Among the compounds of Group 2 metals of the periodic table, the compounds of magnesium, calcium and barium are preferable, the compounds of calcium and magnesium are more preferable, and the compounds of magnesium are further preferable. These metal compounds are mainly used as hydroxides and salts. When used as a salt, examples of the salt include halide salts such as chloride, bromide and iodide; carboxylates such as acetate, formate and benzoate; inorganic salts such as carbonate and nitrate. Sulfonic acid salts such as methanesulfonic acid, toluenesulfonic acid and trifluoromethanesulfonic acid; phosphorus-containing salts such as phosphates, hydrogen phosphate and dihydrogen phosphate; acetylacetonate salts; The catalyst metal can also be used as an alkoxide such as methoxide or ethoxide.

Among these, preferably, acetate, nitrate, sulfate, carbonate, phosphate, hydroxide, halide and alkoxide of at least one metal selected from Group 2 metals of the periodic table are used, More preferably, acetates, carbonates and hydroxides of metals of Group 2 of the periodic table are used, more preferably acetates, carbonates and hydroxides of magnesium and calcium are used, and particularly preferably magnesium and calcium are used. Acetate is used, most preferably magnesium acetate.

In the production of the polycarbonate diol of the present invention, the amount of the carbonate compound used is not particularly limited, but the lower limit is usually 0.35, more preferably 0.50, and further preferably the molar ratio to the total of 1 mol of dihydroxy compounds. Is 0.60, and the upper limit is preferably 1.00, more preferably 0.98, and further preferably 0.97. If the amount of the carbonate compound used exceeds the above upper limit, the ratio of the obtained polycarbonate diol whose terminal group is not a hydroxyl group may increase, or the molecular weight may not fall within a predetermined range. If the amount is less than the above lower limit, the polymerization does not proceed to a predetermined molecular weight. There are cases.

When the above-mentioned transesterification catalyst is used in the production of the polycarbonate diol of the present invention, the amount used is preferably an amount that does not affect the performance even if it remains in the obtained 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 further preferably 50 ppm by weight as a weight ratio of the metal to the weight of the starting dihydroxy compound. Particularly preferred is 10 ppm by weight. 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 an amount at which sufficient polymerization activity is obtained.

The reaction temperature in the transesterification reaction can be arbitrarily selected as long as it is a temperature at which a practical reaction rate can be obtained. Usually, the lower limit of the reaction temperature is preferably 70°C, more preferably 100°C, and further preferably 130°C. The upper limit of the reaction temperature is usually preferably 250°C, more preferably 230°C, and further preferably 200°C. By setting the reaction temperature to the above upper limit or less, it is possible to prevent problems such as coloring of the obtained polycarbonate diol and formation of an ether structure from occurring in quality.

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 process of transesterification reaction for producing a polycarbonate diol. By setting the reaction temperature to 180° C. or lower in all the steps, it becomes possible to prevent the coloring from becoming easy depending on the conditions.

Although the reaction can be carried out under normal pressure, the transesterification reaction is an equilibrium reaction, and the reaction can be biased to the production system by distilling the produced light-boiling component out of the system. Therefore, in the latter half of the reaction, it is usually preferable to employ a reduced pressure condition to distill away the light-boiling components and carry out the reaction. Alternatively, it is possible to gradually lower the pressure from the middle of the reaction to distill off the light-boiling component that is produced and to carry out the reaction. In particular, it is preferable to carry out the reaction by increasing the degree of reduced pressure at the end of the reaction, since by-products such as monoalcohol, phenols and cyclic carbonate can be distilled off.
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 the light-boiling component, the reaction can be carried out while flowing an inert gas such as nitrogen, argon and helium into the reaction system.

When a low boiling carbonate compound or a dihydroxy compound is used in the transesterification reaction, the reaction is carried out near the boiling point of the carbonate compound or the dihydroxy compound in the initial stage of the reaction, and the temperature is gradually raised as the reaction proceeds, A method of advancing the reaction can also be adopted. By doing so, it is possible to prevent the unreacted carbonate compound from being distilled off at the initial stage of the reaction.

Further, in order to prevent the distillation of these raw materials, it is possible to attach a reflux tube to the reactor and carry out the reaction while refluxing the carbonate compound and the dihydroxy compound. In this case, the charged raw materials are not lost and the amount of the reagent is increased. The ratio can be adjusted exactly.

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

The polymerization reaction is terminated when the molecular weight of the produced polycarbonate diol is measured and when the target molecular weight is reached. The reaction time required for the polymerization is largely different depending on the presence or absence and type of the dihydroxy compound, the carbonate compound, and the catalyst used, and therefore cannot be unconditionally specified, but it is usually preferably 50 hours or less, The time is more preferably less than or equal to the time, more preferably less than or equal to 10 hours.

When a catalyst is used during the polymerization reaction, the catalyst usually remains in the obtained polycarbonate diol, and the remaining catalyst may make it impossible to control the polyurethane-forming reaction. In order to suppress the influence of the remaining catalyst, it is preferable to inactivate the transesterification catalyst by adding a catalyst deactivator such as a phosphorus compound in approximately equimolar to the used transesterification catalyst. Furthermore, after the catalyst deactivator is added, the transesterification catalyst can be efficiently deactivated by a heat treatment or the like as described later.

Examples of the phosphorus-based compound used for deactivating the transesterification catalyst include, for example, phosphoric acid, inorganic phosphoric acid such as phosphorous acid, dibutyl phosphate, tributyl phosphate, trioctyl phosphate, triphenyl phosphate, and phosphite. Examples thereof include organic phosphoric acid esters such as triphenyl phosphate. These may be used alone or in combination of two or more.

The amount of the phosphorus compound used is not particularly limited as long as it is almost equimolar to the transesterification catalyst used, and specifically, the upper limit is preferably 1 mol per transesterification catalyst used. It is 5 mol, more preferably 2 mol, and the lower limit is preferably 0.8 mol, more preferably 1.0 mol. When a phosphorus compound in an amount smaller than this is used, the inactivation of the transesterification catalyst in the reaction product is not sufficient, and when the obtained polycarbonate diol is used as a raw material for producing a polyurethane elastomer, the polycarbonate diol is In some cases, the reactivity with respect to the isocyanate group cannot be sufficiently reduced. Further, when a phosphorus compound exceeding this range is used, the obtained polycarbonate diol may be colored.

Deactivation of the transesterification catalyst by adding a phosphorus compound can be performed at room temperature, but heat treatment is more efficient. The temperature of this heat treatment is not particularly limited, but the upper limit is preferably 180° C., more preferably 150° C., further preferably 120° C., particularly preferably 100° C., and the lower limit is preferably 50° C., more preferably Is 60° C., more preferably 70° C. If the temperature is lower than this, it takes time to inactivate the transesterification catalyst, which is not efficient, and the degree of inactivation may be insufficient. On the other hand, if the temperature exceeds 180°C, the obtained polycarbonate diol may be colored.
The reaction time with the phosphorus compound is not particularly limited, but is usually 1 to 5 hours.

The amount of the catalyst remaining in the polycarbonate diol is preferably 100 ppm by weight or less, and more preferably 10 ppm by weight or less in terms of metal, from the viewpoint of controlling the polyurethane-forming reaction. On the other hand, the required amount of the catalyst is preferably 0.01 weight ppm or more, particularly 0.1 weight ppm or more, and especially 5 weight ppm or more in terms of metal.

The reaction product is purified for the purpose of removing impurities having no hydroxyl group at the polymer terminal, phenols, raw material dihydroxy compound, carbonate compound, by-produced light boiling cyclic carbonate, added catalyst and the like in the reaction product. be able to.

For the purification at that time, a method of distilling a light boiling compound by distillation can be adopted. The distillation method is not particularly limited in its form such as vacuum distillation, steam distillation and thin film distillation, and any method can be adopted. Among them, thin film distillation is effective.

The thin film distillation conditions are not particularly limited, but the upper limit of the temperature during thin film distillation is preferably 250°C, and more preferably 200°C. 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 the 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, the effect of removing the light-boiling component can be sufficiently obtained.

The upper limit of the temperature for keeping the polycarbonate diol immediately before thin film distillation is preferably 250°C, more preferably 150°C. The lower limit is preferably 80°C, more preferably 120°C.
By setting the temperature for keeping the temperature of the polycarbonate diol immediately before thin film distillation to the above lower limit or more, it is possible to prevent the fluidity of the polycarbonate diol immediately before thin film distillation from decreasing. On the other hand, when the content is not more than the above upper limit, the polycarbonate diol obtained after thin film distillation can be prevented from being colored.

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

When a diaryl carbonate such as diphenyl carbonate is used as a raw material, phenols are by-produced during the production of polycarbonate diol. Since phenols are monofunctional compounds, they may be an inhibitory factor in the production of polyurethane elastomers, and the urethane bond formed by phenols has a weak bonding force, so the heat generated in subsequent steps May cause dissociation, and isocyanate and phenols may be regenerated and cause problems. Further, since phenols are also stimulants, it is preferable that the residual amount of phenols in the polycarbonate diol is smaller. 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 particularly preferably 100 ppm or less, as a weight ratio to the polycarbonate diol. In order to reduce the phenols in the polycarbonate diol, as described above, the pressure of the polymerization reaction of the polycarbonate diol is set to a high vacuum of 1 kPa or less in absolute pressure, or thin film distillation or the like is performed after the polymerization reaction of the polycarbonate diol. Is effective.

The carbonate compound used as a raw material during production may remain in the polycarbonate diol. The residual amount of the carbonate compound in the polycarbonate diol is not limited, but is preferably as small as possible, and the upper limit of the weight ratio to the polycarbonate diol is preferably 5% by weight, more preferably 3% by weight, further preferably 1% by weight. is there. If the content of the carbonate compound in the polycarbonate diol is too high, the reaction at the time of forming a polyurethane may be hindered. 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 further preferably 0% by weight.

The dihydroxy compound used during production may remain in the polycarbonate diol. The residual amount of the dihydroxy compound in the polycarbonate diol is not limited, but is preferably small, and the weight ratio to the polycarbonate diol is preferably 1% by weight or less, more preferably 0.1% by weight or less, and further preferably Is 0.05% by weight or less. If the amount of the dihydroxy compound remaining in the polycarbonate diol is large, the molecular length of the soft segment portion in the case of using the polyurethane elastomer may be insufficient and desired physical properties may not be obtained.

The polycarbonate diol may contain a cyclic carbonate (cyclic oligomer) produced as a by-product during the production. For example, when 2,2-dialkyl-1,3-propanediol is used as the starting dihydroxy compound of the repeating unit (B), 5,5-dialkyl-1,3-dioxan-2-one or two or more molecules of these are used. If it is more than that, a product such as a cyclic carbonate may be produced and 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 two or more of these molecules are cyclic carbonates. And the like may be generated and contained in the polycarbonate diol. These compounds may cause a side reaction in the polyurethane reaction and cause turbidity. Therefore, the pressure of the polymerization reaction of the polycarbonate diol is set to a high vacuum of 1 kPa or less as an absolute pressure, or the synthesis of the polycarbonate diol is performed. It is preferable to remove as much as possible by performing thin film distillation or the like later. The content of 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 lower limit of the hydroxyl value of the polycarbonate diol of the present invention 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 448.8 mg-. 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 may be too high, which may make it difficult to handle when converting into a polyurethane. If the hydroxyl value exceeds the above upper limit, the flexibility of the obtained polyurethane elastomer may be insufficient.
The hydroxyl value of the polycarbonate diol is specifically measured by the method described in the section of Examples below.

The lower limit of the number average molecular weight (Mn) obtained from the hydroxyl value of the polycarbonate diol used in the present invention is preferably 250, more preferably 300, and further preferably 400. On the other hand, the upper limit is preferably 5,000, more preferably 4,000, further preferably 3,000. If the Mn of the polycarbonate diol is less than the above lower limit, the polyurethane elastomer may not have sufficient flexibility. On the other hand, when the content exceeds the upper limit, the viscosity is increased, which may impair the handling at the time of conversion to polyurethane.
The number average molecular weight (Mn) obtained from the hydroxyl value of the polycarbonate diol is specifically measured by the method described in the section of Examples below.

As the polycarbonate diol of the present invention as a raw material for producing the polyurethane elastomer of the present invention, only one kind may be used, or two or more kinds having different repeating units, their molar ratios, physical properties and the like may be used.

<Polyalkylene ether glycol>
Polyalkylene ether glycol is usually a polyhydroxy compound having one or more ether bonds in the main skeleton in the molecule.

As the repeating unit in the main skeleton of the polyalkylene ether glycol, for example, 1,2-ethylene glycol unit, 1,2-propylene glycol unit, 1,3-propanediol (trimethylene glycol) unit, 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 unit, 1 1,9-nonanediol units, 1,10-decanediol units, 1,4-cyclohexanedimethanol units, and other saturated hydrocarbon groups having 1 to 20 carbon atoms, and a single repeating unit forms a polyalkylene ether glycol. Or may form a copolymerized polyalkylene ether glycol with two or more kinds of repeating units.

The polyalkylene ether glycol used in the present invention includes polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, and copolymerized polytetrahydrofuran of 3-methyltetrahydrofuran and tetrahydrofuran among 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 and the like are preferred from the viewpoint of mechanical strength of the resulting polyurethane elastomer. Polytetramethylene ether glycol (PTMG) is more preferable.

In the present invention, the molecular weight of the polyalkylene ether glycol used as a raw material for the polyurethane elastomer is a hydroxyl value, and the lower limit is usually 200 or more, preferably 300 or more, more preferably 400 or more, further preferably 500 or more, and the upper limit. Is usually 5000 or less, preferably 4000 or less, more preferably 3500 or less, and further 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 handling property during polyurethane formation is not impaired, while the molecular weight of the polyalkylene ether glycol is set to the above lower limit or more, polyurethane This is preferable because it gives sufficient flexibility when used as an elastomer.
The hydroxyl group-based molecular weight of the polyalkylene ether glycol is usually specifically measured by the method described in the section of Examples below.

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

<Hansen solubility parameter>
The polycarbonate diol of the present invention and the above-mentioned polyalkylene ether glycol preferably have a hydrogen bond term δH difference of 3 or less in the Hansen solubility parameter (HPS). Further, it is preferable that each of the interaction hemispheres R showing the affinity with the solvent is 8 or more.
If the difference between the Hansen solubility parameter of the polycarbonate diol of the invention and the Hansen solubility parameter of the polyalkylene ether glycol, δH, which is one of the solubility indices, is 3 or less, the compatibility between the two is high and they are easily dissolved. Indicates. On the other hand, when the δH difference exceeds 3, the compatibility becomes low and the resulting polyurethane elastomer has insufficient physical properties.
The δH difference between the polycarbonate diol of the present invention and the polyalkylene ether glycol is particularly preferably 2 or less.

In order to satisfy such a δH difference, the δH of the polycarbonate diol of the present invention is preferably 7 or more, particularly 8 or more, especially 10 or more, and the δH of the polyalkylene ether glycol is 8 or more, especially 9 or more, especially 11 The above is preferable.

Here, the Hansen solubility parameter (HSP) is an index representing the solubility of a substance to another substance. HSP is a three-dimensional space in which a solubility parameter introduced by Hildebrand is divided into three components, a dispersion term δD, a polar term δP, and a hydrogen bond term δH. The dispersion term δD represents the effect of the dispersive force, the polar term δP represents the effect of the interdipole force, and the hydrogen bond term δH represents the effect of the hydrogen bond force.
δD: Energy derived from intermolecular dispersive force δP: Energy derived from intermolecular polar force δH: Energy derived from intermolecular hydrogen bonding force. (Here, each unit is MPa ^0.5 .)
The definition and calculation of HSP are described in the following documents.
Charles M. Hansen, Hansen Solubility Parameters: A Users Handbook (CRC Press, 2007).

The dispersion term reflects the van der Waals force, the polar term reflects the dipole moment, and the hydrogen bond term reflects the action of water and alcohol. Then, it is possible to determine that those having similar vectors by HSP have high solubility, and the similarity of vectors can be determined by the distance (HSP distance) of the Hansen solubility parameter. In addition, the Hansen solubility parameter can be an index not only for determining the solubility but also for determining how easily a certain substance is present in another certain substance, that is, how good the dispersibility is.

In the present invention, HSP [δD, δP, δH] can be easily estimated from its chemical structure by using, for example, computer software Hansen Solubility Parameters in Practice (HSPiP). Specifically, it is obtained from the chemical structure by the Y-MB method mounted on HSPiP. When the chemical structure is unknown, it is obtained by the sphere method implemented in HSPiP from the results of dissolution tests using a plurality of solvents.

HSP distance (Ra) is, for example, a solute (polycarbonate diol in the present invention, polyalkylene ether glycol) and the HSP and _{(δD 1, δP 1, δH} 1), the solvent (cyclohexane in the present invention, toluene, chloroform, chlorobutane, acetate HSP of butyl, methyl ethyl ketone, 1-nitropropane, n-heptane, tetralin, chlorobenzene, 1-bromonaphthalene, 1,2,4-trichlorobenzene, diiodomethane, methanol, ethyl acetate, N,N-dimethylformamide) (δD ₂ , δP ₂ , δH ₂ ) can be calculated by the following formula.
HSP distance (Ra)=
_{{4 × (δD 1 -δD 2} ) 2 + (δP 1 -δP 2) 2 + (δH 1 -δH 2) 2} 0.5

Further, it is shown that the larger the sphere radius R of the Hansen solubility parameter is, the more the solvents having the higher affinity are, and the higher the compatibility is. Therefore, the sphere radius R of the Hansen solubility parameters of the polycarbonate diol of the present invention and the above-mentioned polyalkylene ether glycol is preferably 8 or more, and more preferably 9 or more.

Here, the radius R of the dissolving sphere indicates the distance from the central coordinate where the polycarbonate diol or the polyalkylene ether glycol exhibits solubility when the coordinate of the Hansen solubility parameter of the polycarbonate diol or the polyalkylene ether glycol is the central coordinate. The radius R of the dissolving sphere is usually determined by conducting a solubility test in which the polycarbonate diol or the polyalkylene ether glycol is dissolved in various solvents in which the Hansen solubility parameter is established.
Specifically, when the Hansen solubility parameter coordinates of all the solvents used in the solubility test are plotted in the Hansen space, the coordinates of the solvent in which the polycarbonate diol or polyalkylene ether glyco is dissolved are inside the sphere, and the solvent that does not dissolve A sphere whose coordinates are outside the sphere (dissolving sphere) is searched for, and the radius of the dissolving sphere is defined as a polycarbonate diol or polyalkylene ether glycol dissolving sphere radius R.

<Use ratio of polycarbonate diol and polyalkylene ether glycol>
The ratio of the polycarbonate diol of the present invention and the polyalkylene ether glycol used for producing the polyurethane elastomer of the present invention is the ratio of the polycarbonate diol of the present invention to the total of the polycarbonate diol of the present invention and the polyalkylene ether glycol (hereinafter, referred to as “PCD ratio”). Is sometimes referred to as ".") is preferably 25 to 90% by weight.
When the PCD ratio is at least the above lower limit, the effect of the chemical resistance by using the polycarbonate diol of the present invention can be sufficiently obtained, and when it is at most the above upper limit, the flexibility by using the polyalkylene ether glycol in combination is obtained. And effects such as elastic recovery can be sufficiently obtained.
The PCD ratio is particularly preferably 35 to 80% by weight, particularly preferably 50 to 80% by weight.

[Method for producing polyurethane elastomer]
The polyurethane elastomer of the present invention can be produced by a general polyurethane reaction except that the polycarbonate diol of the present invention, the polyalkylene ether glycol, the polyisocyanate compound and the above-mentioned chain extender are used.
Here, when a solvent is used in the production of the polyurethane elastomer of the present invention, a step of removing the solvent during molding is required, which is not industrially advantageous. Since the solvent has a large load on the environment, it is preferable to carry out the reaction without a solvent (in the absence of the solvent).
In the present invention, by using the above-mentioned polycarbonate diol of the present invention, which has a high compatibility with polyalkylene glycol such as polytetramethylene glycol, the polyurethane elastomer is excellent in the physical property balance even under the solvent-free condition where the effect of mass transfer is large. Can be obtained.

For example, the polyurethane diol of the present invention can be produced by reacting the polycarbonate diol and polyalkylene ether glycol of the present invention with a polyisocyanate compound and a chain extender in the range of room temperature to 200°C.
Further, the polycarbonate diol and the polyalkylene ether glycol of the present invention are first reacted with an excess of a polyisocyanate compound to produce a prepolymer having an isocyanate group at the terminal, and a chain extender is used to increase the degree of polymerization, The polyurethane elastomers of the invention can be produced.

<Chain terminator>
When producing the polyurethane elastomer of the present invention, a chain terminator having one active hydrogen group can be used, if necessary, for the purpose of controlling the molecular weight of the obtained polyurethane.
These chain terminators include aliphatic monools having one hydroxyl group such as methanol, ethanol, propanol, butanol, and hexanol, diethylamine having one amino group, dibutylamine, n-butylamine, monoethanolamine, diethanolamine. And aliphatic monoamines such as morpholine.
These may be used alone or in combination of two or more.

<Catalyst>
In the polyurethane forming reaction for producing the polyurethane elastomer of the present invention, amine catalysts such as triethylamine, N-ethylmorpholine and triethylenediamine or acid catalysts such as acetic acid, phosphoric acid, sulfuric acid, hydrochloric acid and sulfonic acid, trimethyltin laur It is also possible to use a known urethane polymerization catalyst represented by tin compounds such as phthalate, dibutyltin dilaurate, dioctyltin dilaurate and dioctyltin dineodecanate, and organic metal salts such as titanium compounds. The urethane polymerization catalyst may be used alone or in combination of two or more.

<Polyols other than the polycarbonate diol and polyalkylene ether glycol of the present invention>
In the polyurethane forming reaction in producing the polyurethane elastomer of the present invention, the polycarbonate diol and polyalkylene ether glycol of the present invention may be used in combination with other polyols, if necessary. Here, the polyol other than the polycarbonate diol and the polyalkylene ether glycol of the present invention is not particularly limited as long as it is used in ordinary polyurethane production, and examples thereof include polyester polyol, polycaprolactone polyol, and polycarbonate polyol other than the present invention. Is mentioned. Here, the weight ratio of the polycarbonate diol and polyalkylene ether glycol of the present invention to the combined weight of the polycarbonate diol and polyalkylene ether glycol of the present invention and other polyols is preferably 70% or more, more preferably 90% or more. .. When the weight ratio of the polycarbonate diol and the polyalkylene ether glycol of the present invention is small, the flexibility and durability of the polyurethane elastomer, which is a feature of the present invention, may be lost.

In the present invention, the above-mentioned polycarbonate diol of the present invention may be modified and used in the production of the polyurethane elastomer. Examples of the modification method of the polycarbonate diol include a method of introducing an ether group by adding an epoxy compound such as ethylene oxide, propylene oxide or butylene oxide to the polycarbonate diol, or a cyclic lactone such as ε-caprolactone of the polycarbonate diol, adipic acid or succinic acid. , Sebacic acid, terephthalic acid and other dicarboxylic acid compounds, and a method of introducing an ester group by reacting them with an ester compound thereof. Ether modification is preferable for reasons such as handleability because the viscosity of the polycarbonate diol decreases due to modification with ethylene oxide, propylene oxide or the like. In particular, when the polycarbonate diol of the present invention is modified with ethylene oxide or propylene oxide, the crystallinity of the polycarbonate diol is reduced and the flexibility at low temperature is improved, and in the case of ethylene oxide modification, it is produced using an ethylene oxide modified polycarbonate diol. The water absorbency and moisture permeability of the obtained polyurethane elastomer may be improved. However, when the amount of ethylene oxide or propylene oxide added is increased, physical properties such as mechanical strength, heat resistance, and chemical resistance of the polyurethane elastomer produced using the modified polycarbonate diol are deteriorated. 5 to 50% by weight is suitable, preferably 5 to 40% by weight, more preferably 5 to 30% by weight. In addition, the method of introducing an ester group is preferable for reasons such as handleability because the viscosity of the polycarbonate diol decreases due to modification with ε-caprolactone. The amount of ε-caprolactone added to the polycarbonate diol is preferably 5 to 50% by weight, preferably 5 to 40% by weight, and more preferably 5 to 30% by weight. When the amount of ε-caprolactone added exceeds 50% by weight, the hydrolysis resistance and chemical resistance of the polyurethane elastomer produced by using the modified polycarbonate diol deteriorate.

<Method for producing polyurethane elastomer>
As a method for producing the polyurethane elastomer of the present invention using the above-mentioned reaction agent, a generally used experimental or industrial production method can be used.
As an example thereof, a method in which the polycarbonate diol and polyalkylene ether glycol of the present invention, other polyols used as necessary, a polyisocyanate compound, and a chain extender are mixed at once and reacted (hereinafter, referred to as “one-step method”) Or a polyalkylene ether glycol of the present invention, and other polyols and polyisocyanate compounds that are used if necessary are reacted to prepare a prepolymer having isocyanate groups at both ends. , A method of reacting the prepolymer with a chain extender (hereinafter sometimes referred to as "two-step method"), and the like.

In the two-step method, the polycarbonate diol and the polyalkylene ether glycol of the present invention and a polyol other than the above are reacted in advance with one or more equivalents of a polyisocyanate compound to form an isocyanate intermediate at both ends of a portion corresponding to the soft segment of polyurethane. Through the process of preparing. In this way, once the prepolymer is prepared and then reacted with a chain extender, it may be easier to adjust the molecular weight of the soft segment, and when it is necessary to reliably perform phase separation of the soft segment and the hard segment. Is useful.

<One-step method>
The one-step method is also called a one-shot method and is a method in which the polycarbonate diol and the polyalkylene ether glycol of the present invention, the other polyols, the polyisocyanate compound, and the 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 polycarbonate diol and polyalkylene ether glycol of the present invention and other polyols, the number of hydroxyl groups of the chain extender and the number of amino groups When the total is 1 equivalent, the lower limit is preferably 0.7 equivalents, more preferably 0.8 equivalents, further preferably 0.9 equivalents, particularly preferably 0.95 equivalents, and the upper limit is preferably 3 equivalents. 0.0 equivalents, more preferably 2.0 equivalents, further preferably 1.5 equivalents, particularly preferably 1.1 equivalents.

If the amount of the polyisocyanate compound used is too large, unreacted isocyanate groups cause side reactions, and the viscosity of the resulting polyurethane elastomer tends to be too high, making it difficult to handle or tending to impair flexibility. If the amount is too small, the molecular weight of the polyurethane elastomer does not become sufficiently large, and sufficient strength tends to be unobtainable.

The amount of the chain extender used is not particularly limited, but the number obtained by subtracting the total number of hydroxyl groups of the polycarbonate diol of the present invention, the polyalkylene ether glycol and the other polyols from the number of isocyanate groups of the polyisocyanate compound is 1 equivalent. In this case, 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 3.0 equivalents, more preferably The amount is 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 difficult to process, and if it is too small, the obtained polyurethane elastomer is too soft and has sufficient strength, hardness, and elastic recovery performance. In some cases, the elasticity retention performance may not be obtained, or the heat resistance may deteriorate.

<Two-step method>
The two-step method is also called a prepolymer method and mainly includes the following methods.
(A) Polycarbonate diol and polyalkylene ether glycol of the present invention, a polyol other than that, and an excess polyisocyanate compound are previously added to polyisocyanate compound/(polycarbonate diol of the present invention, polyalkylene ether glycol and other polyols. The reaction equivalent ratio of 1) is reacted from an amount exceeding 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 thereto to produce a polyurethane elastomer. ..
(B) The reaction equivalent of the polyisocyanate compound/(polycarbonate diol of the present invention, polyalkylene ether glycol and other polyols) to the polyisocyanate compound and excess polycarbonate diol, polyalkylene ether glycol and other polyols in advance. A ratio of 0.1 or more to less than 1.0 is reacted 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 is reacted as a chain extender to produce a polyurethane. how to.

The two-step method can be carried out with or without a solvent.
The polyurethane elastomer production by the two-step method can be carried out by any of the methods (1) to (3) described below.
(1) Without using a solvent, first, a polyisocyanate compound is directly reacted with a polycarbonate diol, a polyalkylene ether glycol and another polyol to synthesize a prepolymer, which is directly used for a chain extension reaction.
(2) A prepolymer is synthesized by the method of (1), then dissolved in a solvent and used in the subsequent chain extension reaction.
(3) Using a solvent from the beginning, a polyisocyanate compound is reacted with a polycarbonate diol, a polyalkylene ether glycol and other polyols, and then a chain extension reaction is performed.

In the case of the method (1), the polyurethane is coexistent with the solvent in the chain extension reaction by dissolving the chain extender in a solvent or simultaneously dissolving the prepolymer and the chain extender in the solvent. It is important to get at.
The amount of the polyisocyanate compound used in the method of the two-step method (a) is not particularly limited, but the amount of the isocyanate group when the total number of hydroxyl groups of the polycarbonate diol and the polyalkylene ether glycol and other polyols is 1 equivalent As the number, the lower limit is preferably more than 1.0 equivalent, more preferably 1.2 equivalents, further preferably 1.5 equivalents, and the upper limit is preferably 10.0 equivalents, more preferably 5.0 equivalents. More preferably, it is in the range of 3.0 equivalents.

If the amount of this polyisocyanate compound used is too large, excess isocyanate groups tend to cause side reactions to reach the desired physical properties of the polyurethane elastomer, and if it is too small, the molecular weight of the resulting polyurethane elastomer does not rise sufficiently. Strength and thermal stability may be reduced.
The amount of the chain extender to be used is not particularly limited, but the lower limit is preferably 0.1 equivalent, more preferably 0.5 equivalent, and further preferably 0 per 1 equivalent of the isocyanate group contained in the prepolymer. It is 0.8 equivalent, and the upper limit is preferably 5.0 equivalent, more preferably 3.0 equivalent, and further preferably 2.0 equivalent.

When carrying out the above chain extension reaction, monofunctional organic amines or alcohols may coexist for the purpose of adjusting the molecular weight.
The amount of the polyisocyanate compound used in preparing the prepolymer having a hydroxyl group at the terminal in the method of the two-step method (b) is not particularly limited, but the amount of the polycarbonate diol and the polyalkylene ether glycol and other polyols As for the number of isocyanate groups when the number of total hydroxyl groups is 1 equivalent, the lower limit is preferably 0.1 equivalent, more preferably 0.5 equivalent, further preferably 0.7 equivalent, and the upper limit is preferably 0. It is 99 equivalents, more preferably 0.98 equivalents, still more preferably 0.97 equivalents.

If the amount of this polyisocyanate compound used is too small, the process for obtaining the desired molecular weight in the subsequent chain extension reaction tends to be long and the production efficiency tends to decrease, and if it is too large, the viscosity of the polyurethane elastomer obtained will become too high. The flexibility may be reduced, or the handling may be poor and the productivity may be poor.
The amount of the chain extender used is not particularly limited, but when the total number of hydroxyl groups of the polycarbonate diol and polyalkylene ether glycol used in the prepolymer and other polyols is 1 equivalent, the amount of the isocyanate group used in the prepolymer is As the total equivalents including the equivalents, the lower limit is preferably 0.7 equivalents, more preferably 0.8 equivalents, still more preferably 0.9 equivalents, and the upper limit is preferably less than 1.0 equivalents, more preferably 0. The range is 99 equivalents, more preferably 0.98 equivalents.

When carrying out the above chain extension reaction, monofunctional organic amines or alcohols may coexist for the purpose of adjusting the molecular weight.
The chain extension reaction is usually carried out at 0° C. to 250° C., but this temperature varies depending on the amount of solvent, the reactivity of the raw materials used, the reaction equipment, etc. and is not particularly limited. If the temperature is too low, the reaction may proceed slowly or the production time may be long due to the low solubility of the raw materials and the polymer. If it is too high, side reactions and decomposition of the resulting polyurethane may occur. .. The chain extension reaction may be performed while defoaming under reduced pressure.

Further, a catalyst, a stabilizer and the like can be added to the chain extension reaction, if necessary.
Examples of the catalyst include compounds such as triethylamine, tributylamine, dibutyltin dilaurate, stannous octylate, acetic acid, phosphoric acid, sulfuric acid, hydrochloric acid, and sulfonic acid. One kind may be used alone, or two or more kinds may be used. You may use together. Examples of the stabilizer include 2,6-dibutyl-4-methylphenol, distearyl thiodipropionate, N,N'-di-2-naphthyl-1,4-phenylenediamine, tris(dinonylphenyl)phosphite and the like. Compounds may be used, and one kind may be used alone, or two or more kinds may be used in combination. When the chain extender is a highly reactive one such as a short chain aliphatic amine, it may be carried out without adding a catalyst.
Further, a reaction inhibitor such as tris(2-ethylhexyl) phosphite can also be used.

<Additive>
The polyurethane elastomer of the present invention includes various types of heat stabilizers, light stabilizers, colorants, fillers, stabilizers, ultraviolet absorbers, antioxidants, anti-adhesive agents, flame retardants, antioxidants, inorganic fillers, etc. Additives can be added and mixed within a range that does not impair the properties of the polyurethane elastomer of the present invention.

Examples of the compound usable as the heat stabilizer include phosphoric acid, aliphatic, aromatic or alkyl group-substituted aromatic esters of phosphorous acid, hypophosphorous acid derivatives, phenylphosphonic acid, phenylphosphinic acid, diphenylphosphonic acid, polyphosphonates and dialkyls. Phosphorus compounds such as pentaerythritol diphosphite and dialkylbisphenol A diphosphite; phenol derivatives, especially hindered phenol compounds; thioethers, dithioate salts, mercaptobenzimidazoles, thiocarbanilides, thiodipropionate esters, etc. Compounds containing sulfur; tin compounds such as tin malate and dibutyltin monoxide can be used.

Specific examples of the hindered phenol compound include "Irganox 1010" (trade name: manufactured by BASF Japan Ltd.), "Irganox 1520" (trade name: manufactured by BASF Japan Ltd.), "Irganox 245" (trade name: manufactured by BASF Japan Ltd.). ) And the like.
As the phosphorus compound, "PEP-36", "PEP-24G", "HP-10" (all are trade names: manufactured by ADEKA Corporation), "Irgafos 168" (trade name: manufactured by BASF Japan Ltd.), etc. Is mentioned.

Specific examples of the compound containing sulfur include thioether compounds such as dilauryl thiopropionate (DLTP) and distearyl thiopropionate (DSTP).
Examples of the light stabilizer include benzotriazole-based and benzophenone-based compounds, and specifically, "TINUVIN622LD", "TINUVIN765" (above, manufactured by Ciba Specialty Chemicals Co., Ltd.), "SANOL LS-2626". , "SANOL LS-765" (above, Sankyo Co., Ltd. make) etc. can be used.

Examples of the ultraviolet absorber include "TINUVIN328", "TINUVIN234" (above, manufactured by Ciba Specialty Chemicals Co., Ltd.) and the like.

Examples of colorants include direct dyes, acid dyes, basic dyes, metal complex dyes and other dyes; inorganic pigments such as carbon black, titanium oxide, zinc oxide, iron oxide and mica; and coupling azo-based, condensed azo-based dyes. Examples thereof include anthraquinone-based, thioindigo-based, dioxazone-based, phthalocyanine-based organic pigments and the like.

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

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

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

The amount of these additives added 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 0.01% by weight as a weight ratio to the polyurethane elastomer. It is 10% by weight, more preferably 5% by weight, still more preferably 1% by weight. If the addition amount of the additive is too small, the effect of the addition cannot be sufficiently obtained, and if the addition amount is too large, precipitation or turbidity may occur in the polyurethane elastomer.

<Molecular weight>
The molecular weight of the polyurethane elastomer of the present invention is appropriately adjusted according to its application and is not particularly limited, but it 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, and if it is more than the above upper limit, handling properties such as workability tend to be impaired.

<Use>
INDUSTRIAL APPLICABILITY The polyurethane elastomer of the present invention is excellent in flexibility and durability, has good heat resistance and abrasion resistance, and is excellent in processability, and thus can be used for various applications.

For example, the polyurethane elastomer of the present invention can be used as a cast polyurethane elastomer. Specific applications include rolling rolls, papermaking rolls, office equipment, rolls such as pretension rolls, forklifts, automobile vehicle neutrams, solid tires such as trucks and carriers, casters, and industrial products such as 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 belts of OA equipment, paper feed rolls, cleaning blades for copying, snow plows, toothed belts, surfrollers, and the like.

The polyurethane elastomers of the present invention also find application in applications as thermoplastic elastomers. That is, a molded article having excellent elasticity can be obtained by molding the thermoplastic polyurethane elastomer of the present invention. The molding method of the thermoplastic polyurethane elastomer of the present invention is not particularly limited, and various molding methods generally used for thermoplastic polymers can be used. For example, any molding method such as injection molding, extrusion molding, press molding, blow molding, calendar molding, cast molding, and roll processing can be adopted, and resin plate, film, sheet, tube, hose, belt, roll can be adopted. It is possible to manufacture molded articles of various shapes such as synthetic leather, shoe soles, automobile parts, escalator handrails, road marking members, and fibers.
Specific examples of applications of the thermoplastic polyurethane elastomer of the present invention include food, pneumatic equipment used in the medical field, coating equipment, analytical equipment, physicochemical equipment, metering pumps, water treatment equipment, industrial robots, etc. It can be used for tubes, hoses, spiral tubes, fire hoses, etc. Further, it is used as a belt such as a round belt, a V-belt and a flat belt for various transmission mechanisms, spinning machines, packing machines, printing machines and the like. Further, it can be used for heel tops and soles of footwear, equipment such as couplings, packings, pole joints, bushes, gears, rolls, sports equipment, leisure goods, and belts for watches. Further, examples of automobile parts include oil stoppers, gear boxes, spacers, chassis parts, interior parts, tire chain substitutes and the like. Further, it can be used for films such as keyboard films and automobile films, curl cords, cable sheaths, bellows, conveyor belts, flexible containers, binders, synthetic leather, depinning products and adhesives.

The polyurethane elastomer of the present invention may further be a foamed polyurethane elastomer or polyurethane foam. As a method of foaming or foaming the polyurethane elastomer, for example, any of chemical foaming using water etc. or mechanical foaming such as mechanical floss may be used, and other spray foaming or slab, injection, hard foam obtained by molding, or the like. Similarly, slabs and flexible foams obtained by molding can be used.
Specific applications of the foamed polyurethane elastomer or polyurethane foam include heat insulating materials and vibration insulating materials for electronic devices and buildings, automobile seats, automobile ceiling cushions, bedding such as mattresses, insoles, midsoles and shoe soles.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded.

〔Evaluation methods〕
The evaluation method of the polyalkylene ether glycol used with the polycarbonate diol and the polyurethane elastomer obtained in the following Examples and Comparative Examples is as follows.

[Method for evaluating polycarbonate diol]
<Hydroxyl value/number average molecular weight>
According to JIS K1557-1, the hydroxyl value of the polycarbonate diol was measured by a method using an acetylating reagent.
Further, the number average molecular weight was calculated from the hydroxyl value by the following formula (I).
Number average molecular weight=2×56.1/(hydroxyl value×10 ⁻³ )... (I)

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

[Evaluation method of polyurethane elastomer]
<Molecular weight>
The polyurethane elastomer was dissolved in dimethylacetamide to obtain a dimethylacetamide solution having a concentration of 0.14% by weight. Using a GPC device [manufactured by Tosoh Corporation, product name "HLC-8220" (column: TskgelGMH-XL, 2 tubes)], the dimethylacetamide solution was injected, and the weight average molecular weight (Mw) of the polyurethane elastomer was calculated in terms of standard polystyrene. ) Was measured.

<Evaluation of flexibility: Shore A hardness>
In accordance with JIS K6253 (2012), three sheet-shaped polyurethane elastomers having a size of 4 cm×4 cm and a thickness of 2 mm obtained in Examples and Comparative Examples were stacked to form a test piece having a thickness of 6 mm. Using a rubber hardness meter [Model number "GS-719N (A-TYPE)" manufactured by Teflock Co., Ltd.], a pressure plate of the rubber hardness meter was brought into contact with the test piece, and a measured value after 10 seconds [Shore A hardness] ] Was read. The measurement was performed 5 times at the position where the contact point was separated by 6 mm or more, and the average value was calculated. The closer the Shore A hardness is to 0, the better the flexibility.

<Durability evaluation: Oleic acid resistance>
From the sheet-shaped polyurethane elastomers obtained in Examples and Comparative Examples, a test piece having a size of 3 cm×3 cm and a thickness of 2 mm was cut out, placed in a glass bottle having a capacity of 50 ml containing 10 ml of a test solvent, oleic acid, and heated at 80° C. It was left standing for 18 hours. After leaving still, the front and back of the test piece were lightly wiped with a paper wiper, and then the weight was measured, and the weight increase rate (wt%) from before the test was calculated by the following formula (II). The closer the weight increase rate (%) is to 0%, the better the oleic acid resistance.
Weight increase rate (% by weight)=[(weight after test/weight before test)-1]×100 (II)

[Production and evaluation of polycarbonate diol]
[Synthesis example 1]
In a 5 L glass separable flask equipped with a stirrer, a distillate trap, and a pressure adjusting device, 1,4-butanediol (hereinafter sometimes referred to as “1,4BD”): 908.20 g, neopentyl glycol (hereinafter "NPG" may be referred to): 565.16 g, diphenyl carbonate (hereinafter sometimes referred to as "DPC"): 2726.64 g, magnesium acetate tetrahydrate aqueous solution: 7.92 mL (concentration: 8.4 g/ L, magnesium acetate tetrahydrate: 66.50 mg) was added, and the atmosphere was replaced with nitrogen gas. While stirring, the internal temperature was raised to 160° C., and the contents were heated and dissolved. Thereafter, the pressure was reduced to 24 kPa over 2 minutes, and then the reaction was performed for 90 minutes while removing phenol out of the system. Then, the pressure was reduced to 9.3 kPa over 90 minutes, further reduced to 0.7 kPa over 30 minutes, and the reaction was continued. Then, the temperature was raised to 170° C. to remove phenol and unreacted dihydroxy compounds from the system. While reacting for 60 minutes, a polycarbonate diol-containing composition was obtained. Then, 0.85% phosphoric acid aqueous solution: 2.3 mL was added to deactivate magnesium acetate to obtain a polycarbonate diol-containing composition.

The obtained polycarbonate diol-containing composition was sent to a thin film distillation apparatus at a flow rate of about 20 g/min to perform thin film distillation (temperature: 170° C., pressure: 53 to 67 Pa). As the thin film distillation apparatus, an internal condenser with a diameter of 50 mm, a height of 200 mm and an area of 0.0314 m ² , and a molecular distillation apparatus MS-300 special model manufactured by Shibata Scientific Co., Ltd. were used.

The content of phenols in the polycarbonate diol-containing composition obtained by thin film distillation (measured by the method described below) was 100 ppm by weight or less. The magnesium content of the polycarbonate diol-containing composition (measured by the method described below) was 100 ppm by weight or less.
The polycarbonate diol produced in Synthesis Example 1 is referred to as "PCD1".
Table 1 shows the evaluation results of the properties and physical properties of this PCD1.

(Method for measuring the content of phenols)
The polycarbonate diol-containing composition was dissolved in CDCl ³ and 400 MHz ¹ H-NMR (manufactured by BRUKER, AVANCE400) was measured and calculated from the integrated value of the signal of each component. The detection limit at that time is 100 ppm as the weight of phenol.

(Measurement method of magnesium content)
About 0.1 g of the polycarbonate diol-containing composition was weighed and dissolved in 4 mL of acetonitrile, 20 mL of pure water was added to precipitate the polycarbonate diol, and the precipitated polycarbonate diol was removed by filtration. Then, the filtered solution was diluted with pure water to a predetermined concentration, and the metal ion concentration was analyzed by ion chromatography. The metal ion concentration of acetonitrile used as a solvent was measured as a blank value, and the value obtained by subtracting the metal ion concentration of the solvent was taken as the metal ion concentration of the polycarbonate diol-containing composition. The measurement conditions are as shown in Table 1 below. The magnesium ion concentration was determined using the analysis results and the calibration curve prepared in advance.

[Reference example]
Polycarbonate diol (“Duranol (registered trademark)” manufactured by Asahi Kasei Chemicals Co., Ltd. grade: T-6001) produced from 1,6-hexanediol (1,6HD) as a raw material was used as the polycarbonate diol of Reference Example. This polycarbonate diol is referred to as "PCD2". Table 2 shows the evaluation results of the properties and physical properties of PCD2.

[Polyalkylene ether glycol]
As the polyalkylene ether glycol, a polytetramethylene ether glycol manufactured by Mitsubishi Chemical Corp., which is a commercially available polyalkylene ether glycol having a hydroxyl value-based molecular weight of 1,000, which is measured by a method using an acetylating reagent like polycarbonate diol, is used. PTMG#1000" was used. The melting sphere radius R measured for PTMG #1000 was 12.9.

[Production and evaluation of polyurethane elastomer]
[Example 1]
<Manufacture of polyurethane elastomer>
In a reactor equipped with a 300 mL SUS type stirrer preheated to 90° C., PCD 1: 52.5 g heated to 90° C., PTMG#1000:17.5 g and 4,4′-diphenylmethane diisocyanate heated to 90° C. (Hereinafter, it may be referred to as "MDI"): 36.3 g and tris(2-ethylhexyl) phosphite: 0.4 g as an inhibitor for the urethanization reaction were charged. Then, the reactor was covered and reacted under reduced pressure (10 toll or less) for about 90 minutes while stirring and mixing at 2000 rpm. After the reaction, when the exotherm subsided, 6.2 g of 1,4BD:6.2 g was gradually added to the reactor, stirred for 2 minutes, and then the lid of the reactor was removed. Fluorine resin sheet (fluorine tape Nitoflon 900, thickness 0.1 mm, Nitto Denko Corporation) is attached on the glass plate, and a silicon mold (dimensions: 10 cm x 10 cm, thickness 2 mm) is further installed on it. did. The reaction liquid was poured into the silicon mold, and the upper part of the silicon mold was covered with a glass plate having a fluororesin sheet attached to the lower side. Then, a 4.5 kg weight was placed on the glass plate on the upper part of the mold and inserted into the dryer. It was dried by heating (110° C.×1 hour) in a nitrogen atmosphere in the dryer.

<Melting>
The resulting polyurethane elastomer (size 10 cm×10 cm, thickness 2 mm) was left overnight and then removed from the silicone mold.
A fluororesin sheet and a mold for melt molding were placed in this order on a plate of a heating press machine (manufactured by Toyo Seiki Seisakusho, product name "Mini Test Press") which had been heated to 180°C in advance. As the mold for melt molding, one of two types of 4 cm×4 cm×thickness 2 mm and 10 cm×5 cm×thickness 1 mm was used depending on the application such as the evaluation of physical properties. A polyurethane elastomer was placed in the mold and further covered with a fluororesin sheet. The polyurethane elastomer was melted using a plate of a heat press (pressure: 1 MPa x temperature: 180°C x time: 5 minutes). After melting, the pressure setting of the heating press machine was gradually raised, and heating was performed at a maximum of 10 MPa for 5 minutes to mold. After that, lower the pressure of the heating press machine to remove the polyurethane elastomer molded product, install it on a cooling press machine (Toyo Seiki Seisakusho Co., Ltd., product name "Mini Test Press") that has been cooled by flowing cooling water in advance and quench it. (Pressure 10 MPa×time 2 minutes) to obtain a sheet-shaped polyurethane elastomer molded article. Table 3 shows the evaluation results of the physical properties of the polyurethane elastomer molded product.

[Examples 2 and 3]
A sheet-shaped polyurethane elastomer molded article was obtained in the same manner as in Example 1 except that the raw materials used were changed to the amounts shown in Table 3 and evaluated in the same manner. Table 3 shows the evaluation results of the physical properties of the polyurethane elastomer molded product.

[Comparative Examples 1 to 4]
A sheet-shaped polyurethane elastomer molded article was obtained in the same manner as in Example 1 except that the raw materials used were changed as shown in Table 3 and evaluated in the same manner. Table 3 shows the evaluation results of the physical properties of the polyurethane elastomer molded product.

The following can be seen from Table 3.
In Comparative Example 1 in which only PCD2 having no repeating unit (B) was used as the polyol and no polyalkylene ether glycol was used, the flexibility was poor because the “Shore A hardness” was large.
Even when PCD1 containing the repeating unit (A) and the repeating unit (B) was used, Comparative Example 2 in which the polyalkylene ether glycol was not used was inferior in flexibility because the “Shore A hardness” was large.
In Comparative Example 3 in which only the polyalkylene ether glycol was used without using the polycarbonate diol, the "weight increase rate (% by weight)" of the "oleic acid resistance" was large, and therefore the chemical resistance was poor.
Even if the polycarbonate diol and the polyalkylene ether glycol are used, Comparative Example 4 in which PCD2 having no repeating unit (B) is used in the polycarbonate diol has a large “Shore A hardness” value, and thus is inferior in flexibility.

On the other hand, in Examples 1 to 3 in which PCD1 having a repeating unit (A) and a repeating unit (B) were used together as a polyol, and a polyalkylene ether glycol, flexibility was good and chemical resistance and the like were good. Also has excellent durability.

Claims (14)

A compound having a plurality of isocyanate groups, at least one chain extender selected from the group consisting of polyols and polyamines, a repeating unit represented by the following formula (A) and a repeating unit represented by the following formula (B): A polyurethane elastomer obtained by reacting the polycarbonate diol and a polyalkylene ether glycol.

(In the formula (A), p is an integer of 2 to 20 and n is an integer of 3 to 50. In the formula (B), m is an integer of 1 to 50 and R ¹ is a branched chain. Is an alkylene group having 3 to 20 carbon atoms including. The polyurethane elastomer according to claim 1, wherein the ratio of the polycarbonate diol to the total of the polycarbonate diol and the polyalkylene ether glycol is 25 to 90% by weight. The polyurethane elastomer according to claim 1 or 2, wherein the molar ratio of the repeating unit represented by the formula (B) to the repeating unit represented by the formula (A) contained in the polycarbonate diol is 0.03 to 10. .. The polyurethane elastomer according to any one of claims 1 to 3, wherein p in the formula (A) is an integer of 4 to 6. The polyurethane elastomer according to any one of claims 1 to 4, wherein the ratio of the number of carbon atoms of the branched chain in R ¹ of the formula (B) is 0.05 to 0.5 with respect to the total number of carbon atoms of R ¹ . The repeating unit represented by the formula (B) contained in the polycarbonate diol includes neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol and 2-methyl-1. The polyurethane elastomer according to any one of claims 1 to 5, which is derived from at least one selected from the group consisting of 1,4-butanediol. The polyurethane elastomer according to any one of claims 1 to 6, wherein the molecular weight of the polyalkylene ether glycol is 200 to 5,000 based on the hydroxyl value. The polyalkylene ether glycol is polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, copolymerization polytetramethylene ether glycol of 3-methyltetrahydrofuran and tetrahydrofuran, copolymerization polyether polyol of neopentyl glycol and tetrahydrofuran, ethylene oxide and tetrahydrofuran. 8. The polyurethane elastomer according to claim 1, which is at least one selected from the group consisting of a copolymerized polyether polyol and a copolymerized polyether glycol of propylene oxide and tetrahydrofuran. The difference between the hydrogen bond term δH of the Hansen solubility parameter of the polycarbonate diol and the hydrogen bond term δH of the Hansen solubility parameter of the polyalkylene ether glycol is 3 or less, and the radius R of the melting sphere of the polycarbonate diol and the polyalkylene ether glycol is The polyurethane elastomer according to any one of claims 1 to 8, wherein each is 8 or more. The polyurethane elastomer according to any one of claims 1 to 9, wherein the compound having a plurality of isocyanate groups is an aromatic diisocyanate compound. The polyurethane elastomer according to claim 10, wherein the aromatic diisocyanate compound is at least one selected from the group consisting of 1,4-diphenylmethane diisocyanate, toluene diisocyanate and xylylene diisocyanate. The polyurethane elastomer according to any one of claims 1 to 11, wherein the chain extender is at least one selected from the group consisting of ethylene glycol, 1,4-butanediol and 1,6-hexanediol. The polyurethane elastomer according to any one of claims 1 to 12, wherein the polyurethane elastomer is a thermoplastic elastomer. A method for producing the polyurethane elastomer according to any one of claims 1 to 13,
A method for producing a polyurethane elastomer, wherein the reaction of the compound having a plurality of isocyanate groups, the chain extender, the polycarbonate diol, and the polyalkylene ether glycol is carried out without a solvent.