JP2020125428A - Polyurethane elastomer and method for producing the same - Google Patents

Abstract

To provide a polyurethane elastomer which has high transparency and is excellent in flexibility and durability.SOLUTION: The polyurethane elastomer is obtained by reacting: an aromatic compound having a plurality of isocyanate groups; at least one compound selected from the group consisting of polyols and polyamines; and a polyether polycarbonate diol represented by the following formula (A) and having a number average molecular weight of 600 or more. The ratio of a structural unit derived from the polyether polycarbonate diol represented by the following formula (A) to a structural unit derived from the aromatic compound having a plurality of isocyanate groups is 15-40 mol%. (R represents a C2-10 divalent hydrocarbon group; n represents an integer of 2-30; and m represents an integer of 1-20.)SELECTED DRAWING: None

Description

The present invention relates to a polyurethane elastomer having high transparency and excellent in flexibility, elastic modulus and durability, and a method for producing this 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 thermoplastic polyurethane elastomer obtained by reacting a polyisocyanate and a polyether carbonate diol as a thermoplastic polyurethane elastomer having oil lubrication resistance, tensile strength, and optical characteristics.

Patent Document 4 proposes a thermoplastic polyurethane resin for optical members, which is obtained by reacting a polyether/polycarbonate polyol composition, a chain extender, and an organic diisocyanate.

JP, 2013-163778, A JP, 2005-081278, A JP-A-4-214713 JP, 2005-017183, A

With regard 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, the flexibility, elastic modulus and durability are improved. It was difficult to achieve compatibility between the properties, and the transparency was poor.
That is, in conventional polyurethane elastomers, a combination of a polyether polyol and a 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, However, in the solvent-free system, it was not sufficient to obtain the design properties such as physical properties and transparency of the obtained polyurethane elastomer molded product. For example, in the polyurethane elastomer synthesized by the method proposed in Patent Document 1, since the compatibility of the polyols is poor, the 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 insufficient balance of physical properties such as durability, flexibility and elastic modulus.

Patent Document 3 describes the polyether polycarbonate diol used in the present invention, but the isocyanate composition ratio is high and sufficient flexibility cannot be obtained. Further, the optimum ratio and composition of the polyol for obtaining flexibility and elastic modulus have not been examined.

Patent Document 4 also describes a polyether polycarbonate diol used in the present invention, which is a combination of an aliphatic isocyanate and a chain extender of a side chain diol, and an aromatic isocyanate is used. There is no disclosure of polyurethane elastomers.

An object of the present invention is to provide a polyurethane elastomer having high transparency and excellent in flexibility, elastic modulus and durability.

The present inventor has conducted extensive studies in order to solve the above problems, and as a result, while using an aromatic isocyanate compound as an isocyanate raw material, a polyurethane elastomer is obtained by using a specific polyether polycarbonate diol as a polyol raw material at a predetermined ratio. It was found that the above problems can be solved by manufacturing.

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

[1] A structural unit derived from an aromatic compound having a plurality of isocyanate groups, a structural unit derived from at least one compound selected from the group consisting of polyols and polyamines, and a compound represented by the following formula (A): Which is a polyurethane elastomer containing a structural unit derived from a polyether polycarbonate diol having a number average molecular weight of 600 or more determined from a hydroxyl value, wherein the structural unit derived from an aromatic compound having a plurality of isocyanate groups is A polyurethane elastomer in which the proportion of structural units derived from the polyether polycarbonate diol represented by formula (A) is from 15 mol% to 40 mol %.

(In the above formula (A), R 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. Note that the formula (A ), plural Rs may be the same or different.)

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

[3] The polyurethane elastomer according to [1] or [2], wherein m in the formula (A) is an integer of 2 to 6.

[4] Any of [1] to [3], wherein the aromatic compound having a plurality of isocyanate groups is at least one selected from the group consisting of 1,4-diphenylmethane diisocyanate, toluene diisocyanate and xylylene diisocyanate. The polyurethane elastomer according to claim 1.

[5] At least one compound selected from the group consisting of the polyol and the polyamine 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 [4].

[6] The polyurethane elastomer according to any one of [1] to [5], wherein the polyurethane elastomer is a thermoplastic elastomer.

[7] An aromatic compound having a plurality of isocyanate groups, at least one compound selected from the group consisting of polyols and polyamines, and a number average molecular weight determined from a hydroxyl value represented by the following formula (A): Is a method for producing a polyurethane elastomer by subjecting a polyether polycarbonate diol of 600 or more to an addition polymerization reaction, wherein the addition polymerization reaction is carried out without a solvent.

(In the above formula (A), R 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. Note that the formula (A ), plural Rs may be the same or different.)

According to the present invention, a polyurethane elastomer having high transparency and excellent in flexibility, elastic modulus 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 selected from the group consisting of a structural unit derived from an aromatic compound having a plurality of isocyanate groups (hereinafter sometimes referred to as “aromatic polyisocyanate compound”), a polyol and a polyamine. A structural unit derived from at least one compound (hereinafter sometimes referred to as “chain extender”), and a number average molecular weight of 600 or more, which is represented by the following formula (A) and is determined from a hydroxyl value. A polyurethane elastomer containing a structural unit derived from a polyether polycarbonate diol, which is obtained from a hydroxyl value represented by the following formula (A) with respect to a structural unit derived from an aromatic compound having a plurality of isocyanate groups. The ratio of structural units derived from a polyether polycarbonate diol having a number average molecular weight of 600 or more (hereinafter sometimes referred to as “polyether polycarbonate diol (A)”) (hereinafter, this ratio is referred to as “PEPCD/aromatic isocyanate ratio”). May be referred to as ".") is 15 mol% to 40 mol%, and the aromatic polyisocyanate compound and the chain extender and the polyether polycarbonate diol (A) are used as raw materials. It is produced by adjusting the use ratio of the aromatic polyisocyanate compound and the polyether polycarbonate diol (A) so that the PEPCD/aromatic isocyanate ratio of the obtained polyurethane elastomer becomes a predetermined ratio.

(In the above formula (A), R 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. Note that the formula (A ), plural Rs may be the same or different.)

In the polyurethane elastomer of the present invention, the PEPCD/aromatic isocyanate ratio of 15 mol% to 40 mol% is an important constitutional requirement, and the polyether polycarbonate diol (when the PEPCD/aromatic isocyanate ratio is less than 15 mol% is The effect of improving the transparency and durability due to the inclusion of the structural unit derived from A) cannot be sufficiently obtained, and if it exceeds 40 mol %, the flexibility decreases. From the viewpoint of the balance of transparency, flexibility and durability, the PEPCD/aromatic isocyanate ratio of the polyurethane elastomer of the present invention is preferably 15 mol% to 40 mol %, and 20 mol% to 35 mol %. Is more preferable.

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

For example, 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, 3,3'-dimethyl-4,4'-biphenylene diisocyanate , Aromatic methylene diisocyanate compounds such as polymethylene polyphenyl isocyanate, phenylene diisocyanate and m-tetramethylxylylene diisocyanate. These may be used alone or in combination of two or more.

Among these, 4,4′-in terms of reactivity with a chain extender or a polyether polycarbonate diol (A), high curability of the resulting polyurethane elastomer, and industrial availability at a large amount at low cost. Diphenylmethane 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, and is selected from polyols 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 a branched chain 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 and N,N′-diaminopiperazine;

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

Among these, ethylene glycol, 1, in terms of excellent flexibility and elastic recovery due to excellent phase separation of the soft segment and hard segment of the polyurethane elastomer obtained, and industrially inexpensively available in large quantities, 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 referred to as “polyether carbonate diol” instead of “polyether polycarbonate diol”, but in the present invention, it is represented by formula (A). Such polyether carbonate diol is also referred to as "polyether polycarbonate diol (A)".

(In the above formula (A), R 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. Note that the formula (A ), plural Rs may be the same or different.)

In the above formula (A), R 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 2 having 5 carbon atoms. -Methylbutylene group, particularly preferably n-butylene group. That is, it is preferable that R-O- in the formula (A) is derived from polytetramethylene ether glycol, from the viewpoints of industrial availability and excellent physical properties of the resulting polyurethane elastomer.

In the above formula (A), when n is less than 2, the flexibility of the obtained polyurethane elastomer tends to be poor, and when it exceeds 30, the viscosity and crystallinity of the obtained polyether polycarbonate diol are high and the handleability is deteriorated. The resulting polyurethane elastomer tends to have low transparency. Therefore, n is 2 to 30, preferably 3 to 25, and more preferably 5 to 20.

Further, in the above formula (A), when m is less than 1, the resulting polyurethane elastomer tends to be inferior in durability, and when it exceeds 20, the viscosity is increased and handling during polyurethane conversion may be impaired. Therefore, m is 1 to 20, preferably 2 to 10, and more preferably 2 to 6.

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

The polyoxyalkylene glycol used for producing the polyether polycarbonate diol (A) includes polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, copolymerization of 3-methyltetrahydrofuran and tetrahydrofuran, polytetramethylene ether glycol, neopentyl glycol and tetrahydrofuran. From the viewpoint of the mechanical strength of the obtained polyurethane elastomer, polytetramethylene ether glycol (PTMG) is preferable, for example, a copolymerized polyether polyol of, a copolymerized polyether polyol of ethylene oxide and tetrahydrofuran, and a copolymerized polyether glycol of propylene oxide and tetrahydrofuran. ) Is more preferable.
The polyoxyalkylene glycols may be used alone or in combination of two or more.

The number average molecular weight (Mn) obtained from the hydroxyl value of the polyoxyalkylene glycol used for producing the polyether polycarbonate diol (A) is preferably 300 to 2000, more preferably 400 to 1500, and further preferably 500 to 1200. .. When the molecular weight is less than 300, the flexibility of the obtained polyurethane elastomer tends to be inferior, and when it exceeds 2000, the viscosity and crystallinity of the obtained polyether polycarbonate diol (A) become high, resulting in poor handleability and the obtained polyurethane elastomer. Transparency tends to be low. The number average molecular weight (Mn) obtained from the hydroxyl value is specifically measured by the method described in the section of Examples below.

The carbonate compound that can be used for producing the polyether polycarbonate diol (A) 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, dialkyl carbonate and alkylene carbonate are 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. Dimethyl carbonate and ethylene carbonate are preferable, and ethylene carbonate is more preferable.

When producing the polyether polycarbonate diol (A), an ester exchange catalyst can be used if necessary in order 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-period type 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 lanthanide; compounds of lanthanide-based metals such as lanthanum, cerium, europium, and ytterbium. Among these, from the viewpoint of increasing the transesterification 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 preferred, and compounds of Group 2 metals of the periodic table are even more preferred. Among 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. Sulfonates 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.

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

In the production of the polyether polycarbonate diol (A), the amount of the carbonate compound to be used is not particularly limited, but the lower limit is usually 0.35, more preferably 0. 50, more preferably 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 proportion of the obtained polyether polycarbonate diol (A) in which the terminal group is not a hydroxyl group may increase, or the molecular weight may not fall within the predetermined range. The polymerization may not proceed until.

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

As for the amount of the transesterification catalyst used, the upper limit of the weight ratio of the metal to the weight of the raw material polyoxyalkylene glycol is preferably 500 ppm by weight, more preferably 100 ppm by weight, and more preferably 50 ppm by weight. More preferably, it is particularly preferably 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 further preferably 1 ppm by weight, as an amount capable of obtaining sufficient polymerization activity.

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 quality problems such as coloring of the obtained polyether polycarbonate diol (A) and formation 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 setting the reaction temperature to 180° C. or lower throughout all the steps, it becomes possible to prevent the coloring from becoming easy depending on the conditions.

The transesterification reaction can be carried out at normal pressure, but the transesterification reaction is an equilibrium reaction, and the light-boiling component produced can be distilled out of the system to bias the reaction to the production 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 component and to react. Alternatively, it is possible to gradually lower the pressure from the middle of the reaction to distill away the light-boiling component that is produced and to carry out the reaction. Particularly, it is preferable to carry out the reaction by increasing the degree of reduced pressure at the end of the reaction, because 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 is used in the transesterification reaction, the reaction is carried out near the boiling point of the carbonate compound in the initial stage of the reaction, and as the reaction proceeds, the temperature is gradually raised to further advance the reaction. A method 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.

Furthermore, 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.In this case, the raw materials charged are not lost and the amount ratio of the reagents is accurate. 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 of a tank type, a tube type and a tower type, and a known polymerization tank equipped with various stirring blades may be used. The atmosphere during the temperature rise of the apparatus is not particularly limited, but from the viewpoint of the quality of the product, 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 polyether polycarbonate diol (A) is measured and the target molecular weight is reached. The reaction time required for the polymerization varies greatly depending on the presence and type of the polyoxyalkylene glycol, carbonate compound, and catalyst used, and therefore cannot be unconditionally specified, but it is usually preferably 50 hours or less, It is more preferably 30 hours or less, further preferably 20 hours or less.

When a catalyst is used during 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-forming reaction. In order to suppress the influence of the remaining catalyst, it is preferable to deactivate the transesterification catalyst by adding a catalyst deactivator such as a phosphorus compound in approximately equimolar amount 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, inorganic phosphoric acid such as phosphoric acid and 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-based 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 the obtained polyether polycarbonate diol (A) is used as a raw material for producing a polyurethane elastomer. At times, the reactivity of the polyether polycarbonate diol (A) with respect to isocyanate groups may not be sufficiently reduced. Further, when 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 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, at a temperature higher than 180°C, the obtained polyether polycarbonate diol (A) may be colored. The reaction time with the phosphorus compound is not particularly limited, but is usually 1 to 5 hours.

The amount of 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 reaction. On the other hand, it is preferable that the required amount of the 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. Although the residual amount of the carbonate compound in the polyether polycarbonate diol (A) is not limited, it is preferably small, and the upper limit of the weight ratio to the polycarbonate diol (A) is preferably 5% by weight, more preferably 3% by weight. , And more preferably 1% by weight. If the content of the carbonate compound in the polyether polycarbonate diol (A) is too large, 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 polyoxyalkylene glycol used during production may remain in the polyether polycarbonate diol (A). The residual amount of the polyoxyalkylene glycol in the polyether polycarbonate diol (A) is not limited, but is preferably as small as possible, and the weight ratio to the polyether polycarbonate diol (A) is preferably 1% by weight or less, more preferably Is 0.1% by weight or less, more preferably 0.05% by weight or less. If the amount of remaining polyoxyalkylene glycol in the polyether polycarbonate diol (A) is large, the molecular length of the soft segment portion in the case 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) of the present invention is usually 28.1 mg-KOH/g, preferably 37.4 mg-KOH/g, and the upper limit thereof is usually 187.0 mg-KOH/g, preferably 140. It is 0.3 mg-KOH/g, more preferably 112.2 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 polyether polycarbonate diol (A) 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 polyether polycarbonate diol (A) used in the present invention is 600, preferably 800, more preferably 1000, and even more preferably 1500. On the other hand, the upper limit is preferably 5,000, more preferably 4,000, further preferably 3,000. If the Mn of the polyether polycarbonate diol (A) is less than the lower limit, the polyurethane elastomer may not have sufficient flexibility. On the other hand, if the above upper limit is exceeded, the viscosity may increase and the handling during polyurethane conversion may be impaired.

[Method for producing polyurethane elastomer]
The polyurethane elastomer of the present invention is a polyurethane elastomer obtained by using a polyether polycarbonate diol (A), an aromatic polyisocyanate compound and the above chain extender to obtain a polyether polycarbonate diol (A) and an aromatic polyisocyanate compound. Can be produced by an ordinary polyurethane-forming reaction except that it is charged so as to satisfy the above PEPCD/aromatic isocyanate ratio.
Here, when a solvent is used in the production of the polyurethane elastomer of the present invention, a step of removing the solvent at the time of 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 specific polyether polycarbonate diol (A), it is possible to obtain a polyurethane elastomer that is excellent in homogeneity of the urethane reaction and that is uniform and has excellent physical property balance even under the solvent-free condition.

For example, the polyurethane elastomer of the present invention can be produced by reacting the polyether polycarbonate diol (A) with an aromatic polyisocyanate compound and a chain extender in the range of room temperature to 200°C.
In addition, the polyether polycarbonate diol (A) is first reacted with an excess of an aromatic polyisocyanate compound to produce a prepolymer having an isocyanate group at a terminal, and a chain extender is used to increase the degree of polymerization to obtain the present invention. Polyurethane elastomers of

<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-based catalysts such as triethylamine, N-ethylmorpholine and triethylenediamine, or acid-based catalysts such as acetic acid, phosphoric acid, sulfuric acid, hydrochloric acid and sulfonic acid, trimethyltin laur It is also possible to use known urethane polymerization catalysts 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 polyether polycarbonate diol (A)>
In the polyurethane-forming reaction for producing the polyurethane elastomer of the present invention, the polyether polycarbonate diol (A) may be used in combination with other polyols if necessary. Here, the polyol other than the polyether polycarbonate diol (A) 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. Here, the weight ratio of the polyether polycarbonate diol (A) to the combined weight of the polyether polycarbonate diol (A) and other polyols is preferably 30% or more, more preferably 50% or more. If the weight ratio of the polyether polycarbonate diol (A) is small, the flexibility and durability of the polyurethane elastomer, which is a feature of the present invention, may be lost.

<Method for producing polyurethane elastomer>
As a method for producing the polyurethane elastomer of the present invention using the above-mentioned reaction agent, a production method that is generally used experimentally or industrially can be used.
As an example thereof, a method in which a polyether polycarbonate diol (A), a polyol other than that used as necessary, an aromatic polyisocyanate compound, and a chain extender are mixed and reacted at once (hereinafter, referred to as “one-step method”) May be referred to) or first, a polyether polycarbonate diol (A), a polyol other than that optionally used and an aromatic polyisocyanate compound are reacted to prepare a prepolymer having isocyanate groups at both ends, There is a method of reacting a prepolymer with a chain extender (hereinafter sometimes referred to as "two-step method") and the like.

In the two-step method, the polyether polycarbonate diol (A) and a polyol other than the polyether polycarbonate diol (A) are reacted in advance with 1 equivalent or more of an aromatic polyisocyanate compound to give an isocyanate intermediate at both ends at a portion corresponding to the soft segment of polyurethane. It goes through the step 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 reaction is carried out by charging the polyether polycarbonate diol (A), the other polyol, the aromatic polyisocyanate compound and the chain extender all at once.
The amount of the aromatic polyisocyanate compound used in the one-step method is not particularly limited, but is the total number of hydroxyl groups of the polyether polycarbonate diol (A) and the other polyols, and the total number of hydroxyl groups and amino groups of the chain extender. Is 1 equivalent, the lower limit is preferably 0.7 equivalent, more preferably 0.8 equivalent, further preferably 0.9 equivalent, particularly preferably 0.95 equivalent, and the upper limit is preferably 3. It is 0 equivalent, more preferably 2.0 equivalents, further preferably 1.5 equivalents, and particularly preferably 1.1 equivalents.

If the amount of the aromatic polyisocyanate compound used is too large, unreacted isocyanate groups cause a side reaction, and the viscosity of the resulting polyurethane elastomer becomes too high, making it difficult to handle or tending to impair flexibility. However, 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 when the total number of hydroxyl groups of the polyether polycarbonate diol (A) and other polyols is subtracted from the number of isocyanate groups of the aromatic polyisocyanate compound, the amount is 1 equivalent. The lower limit is preferably 0.7 equivalent, more preferably 0.8 equivalent, further preferably 0.9 equivalent, particularly preferably 0.95 equivalent, and the upper limit is preferably 3.0 equivalent, more preferably 2 equivalent. 0.0 equivalents, more preferably 1.5 equivalents, 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 resulting polyurethane elastomer is too soft and has sufficient strength, hardness, and elastic recovery performance. In some cases, elastic retention performance may not be obtained, or in some cases, heat resistance may deteriorate.

<Two-step method>
The two-step method is also called a prepolymer method and mainly includes the following methods.
(A) The polyether polycarbonate diol (A), the other polyol, and the excess aromatic polyisocyanate compound are added in advance to the aromatic polyisocyanate compound/(polyether polycarbonate diol (A) and other polyol). A method for producing a polyurethane elastomer by producing a prepolymer having an isocyanate group at a molecular chain terminal by reacting at a reaction equivalent ratio of more than 1 to 10.0 or less, and then adding a chain extender to the prepolymer.
(B) Reaction of an aromatic polyisocyanate compound/(polyether polycarbonate diol (A) and other polyols) with an aromatic polyisocyanate compound and excess polyether polycarbonate diol (A) and other polyols in advance. An equivalent ratio of 0.1 to less than 1.0 is reacted to produce a prepolymer having a hydroxyl group at the molecular chain terminal, and then an aromatic polyisocyanate compound having an isocyanate group at the terminal is reacted as a chain extender. A method for producing a polyurethane elastomer.

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, an aromatic polyisocyanate compound is directly reacted with a polyether polycarbonate diol (A) 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, the aromatic polyisocyanate compound, the polyether polycarbonate diol (A) and the other polyol are reacted, and then a chain extension reaction is carried out.

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 aromatic polyisocyanate compound used in the two-step method (a) is not particularly limited, but is an isocyanate when the total number of hydroxyl groups of the polyether polycarbonate diol (A) and the other polyol is 1 equivalent. As the number of groups, the lower limit is preferably more than 1.0 equivalent, more preferably 1.2 equivalents, still more preferably 1.5 equivalents, and the upper limit is preferably 10.0 equivalents, more preferably 5.0 equivalents. The range is equivalent, more preferably 3.0 equivalent.

If the amount of this aromatic polyisocyanate compound used is too large, excess isocyanate groups tend to cause side reactions to make it difficult to reach the desired physical properties of the polyurethane elastomer, and if it is too small, the molecular weight of the resulting polyurethane elastomer is sufficient. However, the strength and thermal stability may decrease.
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 still more preferably 0 equivalent to 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 and alcohols may be allowed to coexist for the purpose of adjusting the molecular weight.
The amount of the aromatic 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 polyether polycarbonate diol (A) and other As for the number of isocyanate groups when the total number of hydroxyl groups of the polyol 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 preferable. It is 0.99 equivalents, more preferably 0.98 equivalents, still more preferably 0.97 equivalents.

If the amount of the aromatic 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 be low. The flexibility of the elastomer 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 polyether polycarbonate diol (A) used in the prepolymer and the other polyol is 1 equivalent, the amount of the isocyanate group used in the prepolymer is As a total equivalent 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 and alcohols may be allowed to 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 progress of the reaction may be slow, or the solubility of the raw materials or the polymer may be low, which may increase the production time.If it is too high, side reactions or 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 octoate, 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, distearylthiodipropionate, 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.
Also, a reaction inhibitor such as tris(2-ethylhexyl) phosphite can be used.

<Additive>
The polyurethane elastomer of the present invention includes various kinds of heat stabilizers, light stabilizers, colorants, fillers, stabilizers, ultraviolet absorbers, antioxidants, anti-adhesive agents, flame retardants, anti-aging agents, inorganic fillers and the like. 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 that can be used 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, particularly 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 the colorant 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 and 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 the flame retardant 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 lower limit of the amount of these additives added to the polyurethane elastomer is preferably 0.01% by weight, more preferably 0.05% by weight, further preferably 0.1% by weight, and the upper limit is preferably 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 it is too large, the polyurethane elastomer may be precipitated or turbidity may occur.

<Molecular weight>
The molecular weight of the polyurethane elastomer of the present invention is appropriately adjusted depending on 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, More preferably, it is 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>
The polyurethane elastomer of the present invention has high transparency, is excellent in flexibility and elastic modulus, durability, has good heat resistance and abrasion resistance, and is excellent in processability, and therefore, can be used in various applications. You can

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, solid tires such as automobiles new trams, trolleys, 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. Molded products of various shapes such as synthetic leather, shoe soles, automobile parts, escalator handrails, road marking members, and fibers can be manufactured.

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 in various transmission mechanisms, spinning machines, packing machines, printing machines, and the like. Further, it can be used for heel tops and soles of footwear, device parts such as couplings, packings, pole joints, bushes, gears, rolls, sports goods, 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 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 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 method〕
The evaluation methods of the polyether polycarbonate diols and polyurethane elastomers obtained in the following Examples and Comparative Examples and the polyoxyalkylene glycols used are as follows.

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

[Evaluation 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. The dimethylacetamide solution was injected using a GPC device [manufactured by Tosoh Corporation, product name “HLC-8220” (column: TskgelGMH-XL, 2 tubes)], 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 higher the flexibility. In addition, a preferred range for achieving both flexibility and mechanical strength is Shore A hardness of 70 to 95.

<Tensile test>
In accordance with JIS K6301 (2010), a sheet-shaped polyurethane elastomer having a thickness of 1 mm obtained in Examples and Comparative Examples was cut into a strip-shaped test piece having a width of 10 mm and a length of 100 mm, and a tensile tester (Orientech Co., Ltd.) was used. Manufactured by Tensilon UTM-III-100)), a chucking distance of 50 mm, a pulling speed of 500 mm/min, a temperature of 23° C., and a relative humidity of 55%. And stress at 300% elongation: 100% modulus and 300% modulus were measured. Those having a 100% modulus of 5 MPa or more and a 300% modulus of 7 MPa or more have a high elastic modulus.

<Durability evaluation: oleic acid resistance>
A 3 cm×3 cm test piece was cut out from the sheet-shaped polyurethane elastomer having a thickness of 2 mm obtained in Examples and Comparative Examples, and the cut piece was put into a glass bottle having a capacity of 50 ml containing 10 ml of oleic acid as a test solvent, and then at 80° C. The state after standing for 18 hours was visually observed and evaluated as follows.
○: The shape of the film is maintained.
X: The film is damaged by swelling.

<Evaluation of transparency>
A 3 cm×3 cm test piece was cut out from the sheet-shaped polyurethane elastomer having a thickness of 2 mm obtained in Examples and Comparative Examples, and visually observed to determine transparency as follows.
◯: The entire film is transparent ×: The film is partially clouded.

[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 adjusting device, a distillation column containing 30 mmφ ordered packing, and a fractionator was used as a polytetramethylene ether glycol “PTMG#650” (number average molecular weight) manufactured by Mitsubishi Chemical Corporation. 655): 865 g (1.3 mol), ethylene carbonate (EC): 176 g (2.0 mol), and magnesium (II) acetylacetonate: 95 mg (0.43 mmol) were added, and the atmosphere was replaced with nitrogen gas. The internal temperature was raised to 150° C. with stirring 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 performed for 12 hours while removing ethylene glycol and ethylene carbonate with the azeotropic composition outside the system. Then, the reaction was performed at 150° C. to 170° C. while lowering the pressure to 1 kPa over 12 hours. It was confirmed by ¹ H-NMR that the number average molecular weight was about 1600, and a polyether polycarbonate diol-containing composition was obtained.
Then, 8.5 mL of phosphoric acid aqueous solution: 0.4 mL (0.4 mmol) was added to the polyether polycarbonate diol-containing composition to deactivate the catalyst. Then, the distillation column was removed, and residual monomers were removed at 0.5 kPa and 170° C. to obtain 815 g of a polyether polycarbonate diol-containing composition.

The obtained polyether polycarbonate diol-containing composition was sent to a thin film distillation apparatus at a flow rate of 20 g/min, and thin film distillation (temperature: 210° C., pressure: 53 Pa) was performed to obtain a polyether polycarbonate diol. As the thin film distillation apparatus, a molecular distillation apparatus MS-300 special model manufactured by Shibata Scientific Co., Ltd. with an internal condenser having a diameter of 50 mm, a height of 200 mm and an area of 0.0314 m ² and having a jacket 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 PEPCD1.

[Synthesis example 2]
The raw materials used are polytetramethylene ether glycol "PTMG#250" (number average molecular weight 247): 423 g (1.7 mol) manufactured by Mitsubishi Chemical Corporation, ethylene carbonate (EC): 176 g (2.0 mol), magnesium (II ) Acetylacetonate: A polyether polycarbonate diol was obtained by performing the same reaction as in Synthesis Example 1 except that the amount was changed to 62 mg (0.28 mmol). The polyether polycarbonate diol produced in Synthesis Example 2 is referred to as "PEPCD2".
Table 1 shows the evaluation results of the properties and physical properties of this PEPCD2.

[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., PEPCD 1:85.0 g and 4,4′-diphenylmethane diisocyanate (hereinafter sometimes referred to as “MDI”) heated to 90° C.: 39 0.4 g and tris(2-ethylhexyl phosphite): 0.86 g as an inhibitor for the urethanization reaction were charged. Then, the reactor was capped and reacted under reduced pressure (10 torr or less) for about 90 minutes while stirring and mixing at 2000 rpm. After the reaction, when heat generation stopped, 9.2 g of 1,4BD: 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 set on it. did. The reaction solution was poured into this 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 weight of 4.5 kg 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 "Minitest Press") which had been heated to 180°C in advance. As a 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 use such as the evaluation of physical properties. The mold was filled with polyurethane elastomer, 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 increased, 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 (manufactured by Toyo Seiki 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 2 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 to the amounts shown in Table 2 and evaluated in the same manner. Table 2 shows the evaluation results of the physical properties of the polyurethane elastomer molded product.

The following can be seen from Table 2.
In Example 1 in which the polyether polycarbonate diol (A) is used within the scope of the present invention, transparency, flexibility and durability are all excellent.
On the other hand, in Comparative Examples 1 and 3 using the polyether polycarbonate diol other than the polyether polycarbonate diol (A) according to the present invention, the balance between flexibility and elastic modulus is poor.
Even when the polyether polycarbonate diol (A) according to the present invention is used, Comparative Example 2 in which the usage ratio is too large with respect to the aromatic polyisocyanate compound also has a poor balance of flexibility and elastic modulus.
Comparative Example 4, which uses the raw material polytetramethylene ether glycol instead of the polyether polycarbonate diol (A) according to the present invention, is inferior in durability and transparency.

Claims (7)

A structural unit derived from an aromatic compound having a plurality of isocyanate groups, a structural unit derived from at least one compound selected from the group consisting of polyols and polyamines, and a hydroxyl group represented by the following formula (A): A polyurethane elastomer containing a structural unit derived from a polyether polycarbonate diol having a number average molecular weight of 600 or more determined from its valency,
A polyurethane elastomer in which the ratio of the structural unit derived from the polyether polycarbonate diol represented by the following formula (A) to the structural unit derived from the aromatic compound having a plurality of isocyanate groups is from 15 mol% to 40 mol %. ..

(In the above formula (A), R 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. Note that the formula (A ), plural Rs may be the same or different.) The polyurethane elastomer according to claim 1, wherein R in the formula (A) is an n-butylene group and/or a 2-methylbutylene group. The polyurethane elastomer according to claim 1 or 2, wherein m in the formula (A) is an integer of 2 to 6. The aromatic compound having a plurality of isocyanate groups is at least one selected from the group consisting of 1,4-diphenylmethane diisocyanate, toluene diisocyanate and xylylene diisocyanate. Polyurethane elastomer. The at least one compound selected from the group consisting of the polyol and the polyamine is at least one compound selected from the group consisting of ethylene glycol, 1,4-butanediol and 1,6-hexanediol. 4. The polyurethane elastomer according to any one of 4 above. The polyurethane elastomer according to any one of claims 1 to 5, wherein the polyurethane elastomer is a thermoplastic elastomer. An aromatic compound having a plurality of isocyanate groups, at least one compound selected from the group consisting of polyols and polyamines, and a number average molecular weight calculated from a hydroxyl value of 600 or more, which is represented by the following formula (A): A method for producing a polyurethane elastomer by subjecting the polyether polycarbonate diol of
A method for producing a polyurethane elastomer, wherein the addition polymerization reaction is carried out in the absence of a solvent.

(In the above formula (A), R 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. Note that the formula (A ), plural Rs may be the same or different.)