JP2020164625A - Polyurethane elastomer - Google Patents

Abstract

To provide a polyurethane elastomer excellent in mechanical strength.SOLUTION: The polyurethane elastomer contains: a reaction product of a polyisocyanate component and a polyol component containing a polyester polyol; and a hydrocarbon-based synthetic oil. The polyester polyol is a reaction product of a polybasic acid containing succinic acid and a polyhydric alcohol. The blending ratio of the hydrocarbon-based synthetic oil is 0.001 pt.mass or more and 0.2 pt.mass or less based on 100 pts.mass of the polyester polyol.SELECTED DRAWING: None

Description

The present invention relates to a polyurethane elastomer, and more particularly to a polyurethane elastomer used as a member of various industrial equipment.

Polyurethane elastomer is used as a member of various industrial equipment because it has excellent mechanical strength and abrasion resistance and is easy to process.

In particular, polyurethane elastomers using polyester polyol, which is a reaction product of succinic acid and polyhydric alcohol, are used as squeegees for screen printing because of their excellent solvent resistance.

Specifically, a polyester polyol composition containing a polyester polyol obtained by reacting a glycol component with a polycarboxylic acid component essentially containing succinic acid, and a polyurethane elastomer composition containing a polyisocyanate are thermoset. There is known a screen printing squeegee obtained by (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-168690

On the other hand, a polyurethane elastomer using a polyester polyol which is a reaction product of succinic acid and a polyhydric alcohol may be required to have even higher mechanical strength.

An object of the present invention is to provide a polyurethane elastomer having excellent mechanical strength.

The present invention [1] contains a reaction product of a polyisocyanate component and a polyol component containing a polyester polyol, and a hydrocarbon-based synthetic oil, and the polyester polyol is a reaction product of a polybasic acid and a polyhydric alcohol. The polybasic acid contains succinic acid and is a product.
A polyurethane elastomer in which the blending ratio of the hydrocarbon-based synthetic oil is 0.001 part by mass or more and 0.2 part by mass or less with respect to 100 parts by mass of the polyester polyol.

In the present invention [2], the hydrocarbon-based synthetic oil contains the polyurethane elastomer according to the above [1], which is an ethylene-propylene copolymer.

The present invention [3] includes the polyurethane elastomer according to the above [1] or [2], wherein the hydrocarbon-based synthetic oil has a kinematic viscosity of 150 mm ² / s or less at 100 ° C.

In the present invention [4], the polyurethane elastomer according to any one of the above [1] to [3], wherein the polyol component contains 1,4-bis (2-hydroxyethoxy) benzene.

The polyurethane elastomer of the present invention contains a reaction product of a polyisocyanate component and a polyol component containing a polyester polyol which is a reaction product of a polybasic acid containing succinic acid and a polyhydric alcohol.

Therefore, the solvent resistance can be improved.

In addition, this polyurethane elastomer contains a predetermined ratio of hydrocarbon-based synthetic oil.

Therefore, the mechanical strength (specifically, the tensile strength and the elongation at the time of cutting) can be improved.

The polyurethane elastomer of the present invention contains a reaction product of a polyisocyanate component and a polyol component including a polyester polyol.

Examples of the polyisocyanate component include polyisocyanates such as aromatic polyisocyanates, aromatic aliphatic polyisocyanates, alicyclic polyisocyanates, and aliphatic polyisocyanates.

Examples of the aromatic polyisocyanate include 4,4'-, 2,4'-or 2,2'-diphenylmethane diisocyanate or a mixture thereof (MDI), 2,4- or 2,6-tolylene diisocyanate or a mixture thereof. (TDI), 4,4'-toluidine diisocyanate (TODI), 1,5-naphthalenediocyanate (NDI), m- or p-phenylenediocyanate or a mixture thereof, 4,4'-diphenyl diisocyanate, 4,4'-diphenyl ether Examples include aromatic diisocyanates such as diisocyanates.

Examples of the aromatic aliphatic polyisocyanate include 1,3- or 1,4-bis (isocyanatomethyl) benzene (also known as 1,3- or 1,4-xylene diisocyanate) or a mixture thereof (XDI), 1. , 3- or 1,4-tetramethylxylene diisocyanate or a mixture thereof (TMXDI), aromatic aliphatic diisocyanates such as ω, ω'-diisocyanate-1,4-diethylbenzene and the like.

Examples of the alicyclic polyisocyanate include 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate (isophorone diisocyanate, IPDI), 4,4'-, 2,4'-or 2,2'-methylenebis. (Cyclohexyl isocyanate) or a mixture thereof (H ₁₂ MDI), 1,3- or 1,4-bis (isocyanatomethyl) cyclohexane or a mixture thereof (H ₆ XDI), bis (isocyanatomethyl) norbornan (NBDI), 1 , 3-Cyclopentene diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate and other alicyclic diisocyanates.

Examples of the aliphatic polyisocyanate include hexamethylene diisocyanate (hexane diisocyanate) (HDI), pentamethylene diisocyanate (pentane diisocyanate) (PDI), tetramethylene diisocyanate, trimethylene diisocyanate, 1,2-, 2,3- or 1 , 3-Burine diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate and other aliphatic diisocyanates.

Examples of the polyisocyanate include aromatic diisocyanates, and more preferably diphenylmethane diisocyanates, from the viewpoint of solvent resistance.

The polyisocyanate includes a polyisocyanate derivative, for example, a multimer of the above-mentioned polyisocyanate (for example, a dimer or a trimeric (for example, an isocyanurate derivative or an iminooxadiazinedione derivative), a pentamer, or 7). Allophanate derivatives (eg, allophanate derivatives produced by the reaction of the above-mentioned polyisocyanates with monovalent alcohols or dihydric alcohols), polyol derivatives (eg, polyisocyanates and trihydric alcohols (eg, trimethylol)). Polyol derivatives (alcohol adducts) produced by reaction with propane etc.), biuret derivatives (eg biuret derivatives produced by reaction of the above-mentioned polyisocyanates with water or amines), urea derivatives (eg) Urea derivatives produced by the reaction of the above-mentioned polyisocyanate and diamine), oxadiazine trione derivatives (for example, oxadiazine trione produced by the reaction of the above-mentioned polyisocyanate with carbon dioxide gas), carbodiimide derivatives (the above-mentioned Carbodiimide derivatives produced by the decarbonate condensation reaction of polyisocyanates), uretdione derivatives, uretonimine derivatives and the like can also be mentioned.

The polyisocyanate derivative is preferably a carbodiimide derivative.

Examples of the polyisocyanate component include a polyisocyanate derivative, more preferably a carbodiimide derivative of polyisocyanate, further preferably a carbodiimide derivative of aromatic diisocyanate, and particularly preferably a carbodiimide derivative of diphenylmethane diisocyanate (liquid diphenylmethane diisocyanate). Be done.

The polyisocyanate component is also available as a commercially available product, and more specific examples thereof include Cosmoate LSI-990 (liquid diphenylmethane diisocyanate) manufactured by Mitsui Chemicals, Inc.

The isocyanate group concentration of the polyisocyanate component is, for example, 4% by mass or more, preferably 20% by mass or more, and for example, 50% by mass or less, preferably 49% by mass or less.

The polyisocyanate component can be used alone or in combination of two or more.

The polyol component includes a polyester polyol as an essential component.

The polyester polyol can be obtained by a known esterification reaction, that is, a condensation reaction between a polybasic acid and a polyhydric alcohol, an ester exchange reaction between an alkyl ester of a polybasic acid and a polyhydric alcohol, and the like. That is, the polyester polyol is a reaction product of a polybasic acid (including an alkyl ester of a polybasic acid) and a polyhydric alcohol.

The polybasic acid contains succinic acid as an essential component and other polybasic acids as an optional component.

If the polybasic acid contains succinic acid, the solvent resistance can be improved.

Other polybasic acids include, for example, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid, dodecanedioic acid and dimer acid, and alicyclic dicarboxylic acids such as hexahydrophthalic acid and tetrahydrophthalic acid. For example, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, dialkyls thereof (for example, C1-6 alkyl esters), or mixtures thereof.

Other polybasic acids can be used alone or in combination of two or more.

The polybasic acid preferably contains only succinic acid.

Examples of the polyhydric alcohol include those similar to those of low molecular weight polyols described later, and preferably dihydric alcohols.

The polyhydric alcohol can be used alone or in combination of two or more.

Further, the polyester polyol is also available as a commercially available product, and more specific examples thereof include Takelac U-6230 manufactured by Mitsui Chemicals, Inc.

The average hydroxyl value (OH value) of the polyester polyol is, for example, 22 mgKOH / g or more, and for example, 112 mgKOH / g or less.

In addition, the polyol component includes other polyols as optional components.

Examples of other polyols include high molecular weight polyols (excluding polyester polyols), low molecular weight polyols, and the like.

The high molecular weight polyol is a compound having two or more hydroxyl groups and having a number average molecular weight of 400 or more and 10,000 or less, and is, for example, a polyether polyol (for example, a polyoxyalkylene polyol such as polypropylene glycol, a polytetramethylene ether polyol, etc.). , Polycarbonate polyol, polyurethane polyol (for example, a polyol obtained by urethane-modifying a polyether polyol, a polycarbonate polyol, etc. with polyisocyanate), an epoxy polyol, a vegetable oil polyol, a polyolefin polyol, an acrylic polyol, a vinyl monomer-modified polyol, and the like.

The low molecular weight polyol is a compound having two or more hydroxyl groups and having a number average molecular weight of 40 or more and less than 400, preferably 300 or less, and examples thereof include dihydric alcohols and trihydric alcohols.

Examples of the dihydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butylene glycol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol and the like. Examples of aliphatic diols include alicyclic diols such as cyclohexanediol and hydride bisphenol A, and aromatic diols such as bisphenol A and 1,4-bis (2-hydroxyethoxy) benzene.

Examples of the trihydric alcohol include glycerin, trimethylolpropane, triisopropanolamine and the like.

Other polyols are preferably low molecular weight polyols, more preferably dihydric alcohols, even more preferably aromatic diols (aromatic ring-containing diols), and particularly preferably 1,4-bis (2-hydroxyethoxy) benzene. Can be mentioned.

If the polyol component contains 1,4-bis (2-hydroxyethoxy) benzene, the mechanical strength (specifically, the tensile strength and the elongation at the time of cutting) can be improved.

Other polyols can be used alone or in combination of two or more.

When the polyol component contains a polyester polyol and another polyol, the mixing ratio of the other polyol is, for example, 1 part by mass or more, preferably 5 parts by mass or more with respect to 100 parts by mass of the polyester polyol. Further, for example, it is 20 parts by mass or less, preferably 15 parts by mass or less.

Further, if necessary, a urethanization catalyst can be added to the polyol component.

Examples of the urethanization catalyst include known urethanization catalysts such as amines and organometallic compounds (for example, dibutyltin dilaurate).

The blending ratio of the urethanization catalyst is, for example, 1 ppm or more, and for example, 500 ppm or less with respect to the polyester polyol.

In addition, the polyurethane elastomer contains a hydrocarbon-based synthetic oil as an essential component.

The hydrocarbon-based synthetic oil is a copolymer of ethylene and an α-olefin having 3 or more carbon atoms.

Examples of α-olefins having 3 or more carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, and 1-tetradecene. , 1-Hexadecene, 1-octadecene, 1-eicocene and the like, preferably propylene.

That is, the hydrocarbon-based synthetic oil is preferably an ethylene-propylene copolymer.

If the hydrocarbon-based synthetic oil is an ethylene-propylene copolymer, the mechanical strength (specifically, the tensile strength and the elongation at the time of cutting) can be improved.

Hydrocarbon-based synthetic oils are also available as commercial products. More specifically, for example, the Lucant series (ethylene propylene copolymer) manufactured by Mitsui Chemicals, and Disparon P- manufactured by Kusumoto Kasei Co., Ltd. For example, 450.

The kinematic viscosity of the hydrocarbon-based synthetic oil at 100 ° C. (based on JIS K-2283 (2000)) is, for example, 2500 mm ² / s or less, preferably 1500 mm ² / s or less, more preferably 1000 mm ² / s. Hereinafter, it is more preferably 300 mm ² / s or less, particularly preferably 150 mm ² / s or less, most preferably 120 mm ² / s or less, and for example, from the viewpoint of suppressing bleeding on the surface of the polyurethane elastomer. It is 20 mm ² / s or more, preferably 40 mm ² / s or more.

Hydrocarbon-based synthetic oils can be used alone or in combination of two or more.

The blending ratio of the hydrocarbon-based synthetic oil is 0.001 part by mass or more, preferably 0.005 part by mass or more, more preferably 0.01 part by mass or more, and more preferably 0.01 part by mass or more, based on 100 parts by mass of the polyester polyol. , 0.2 parts by mass or less, preferably 0.11 parts by mass or less, more preferably 0.08 parts by mass or less, still more preferably 0.04 parts by mass or less, and particularly preferably 0.02 parts by mass or less. Is.

When the blending ratio of the hydrocarbon-based synthetic oil is at least the above lower limit, the mechanical strength (specifically, the tensile strength and the elongation at the time of cutting) can be improved.

On the other hand, if the blending ratio of the hydrocarbon-based synthetic oil is less than the above lower limit, the mechanical strength (specifically, the tensile strength and the elongation at the time of cutting) decreases.

Further, when the blending ratio of the hydrocarbon-based synthetic oil is not more than the above upper limit, the mechanical strength (specifically, the tensile strength and the elongation at the time of cutting) can be improved.

On the other hand, if the blending ratio of the hydrocarbon-based synthetic oil exceeds the above upper limit, the mechanical strength (specifically, the tensile strength and the elongation at the time of cutting) decreases.

When the above kinematic viscosity of the hydrocarbon-based synthetic oil exceeds 150 mm ² / s, the compounding ratio of the hydrocarbon-based synthetic oil is, for example, 0.02 parts by mass or less, preferably 0.01. By setting the content to parts by mass or less, bleeding on the surface of the polyurethane elastomer can be suppressed.

Then, in order to produce the polyurethane elastomer, first, a polyol composition is prepared.

To prepare the polyol composition, the polyol component and the hydrocarbon-based synthetic oil are mixed and heated.

As the heating conditions, the heating temperature is, for example, 110 ° C. or higher, and for example, 150 ° C. or lower. When the polyol component contains 1,4-bis (2-hydroxyethoxy) benzene, the heating temperature is, for example, 120 ° C. from the viewpoint of melting 1,4-bis (2-hydroxyethoxy) benzene. It is above, and for example, it is 150 degreeC or less.

As a result, the polyol composition is prepared.

Then, the polyurethane elastomer composition is prepared by mixing and stirring the polyol composition and the polyisocyanate component while continuing heating.

Specifically, the equivalent ratio (isocyanate group / hydroxyl group) of the isocyanate group of the polyisocyanate component to the hydroxyl group in the polyol composition is, for example, 0.7 or more, preferably 0.9 or more, and for example. The polyol composition and the polyisocyanate component are mixed so as to be 1.1 or less, preferably less than 1.0.

As a result, the polyurethane elastomer composition is prepared.

Then, if necessary, defoaming is performed, and this polyurethane elastomer composition is injected into a preheated mold (for example, preheated to 90 ° C. or higher and 120 ° C. or lower), and a curing reaction (primary curing) (polyisocyanate component) is performed. Reaction with the polyol component).

As the primary curing conditions, the primary curing temperature is, for example, 100 ° C. or higher, and for example, 130 ° C. or lower, and the primary curing time is, for example, when a urethanization catalyst is blended with the polyol component. , 0.5 hours or more and 2 hours or less, and when the urethanization catalyst is not added to the polyol component, for example, 3 hours or more and 24 hours or less.

Then, after the primary curing, the mold is removed and the secondary curing is performed.

As the secondary curing conditions, the secondary curing temperature is, for example, 100 ° C. or higher, and for example, 130 ° C. or lower, and the secondary curing time is the sum of the primary curing time and the secondary curing time. For example, it is adjusted to be 15 hours or more and 16 hours or less, specifically, 6 hours or more, and for example, 16 hours or less.

Thereby, a polyurethane elastomer molded into a desired shape can be obtained.

Further, after the secondary curing, if necessary, it can be aged at room temperature (25 ° C.) for, for example, 72 hours or more, and usually 168 hours or less.

If necessary, the polyurethane elastomer may contain known additives such as plasticizers, blocking inhibitors, heat-resistant stabilizers, weather-resistant stabilizers (light-resistant stabilizers), antioxidants, ultraviolet absorbers, and mold release agents. , A catalyst, and further, a pigment, a dye, a lubricant, a filler, an antioxidant, a flame retardant, and the like can be blended in an appropriate ratio. These additives may be added to each component, may be added at the time of mixing / dissolving each component, or may be added after mixing.

The shore A hardness of such a polyurethane elastomer (according to JIS K7312 (1996)) is, for example, 60 A or more, preferably 60 A or more when the polyol component contains 1,4-bis (2-hydroxyethoxy) benzene. When it is 70 A or more and, for example, 95 A or less and the polyol component does not contain 1,4-bis (2-hydroxyethoxy) benzene, for example, 20 A or more, preferably 30 A or more, more preferably. Is 50 A or more, and is, for example, less than 60 A.

In addition, such a polyurethane elastomer contains a reaction product of a polyisocyanate component and a polyol component containing a polyester polyol which is a reaction product of a polybasic acid containing succinic acid and a polyhydric alcohol.

Therefore, the solvent resistance can be improved.

In addition, this polyurethane elastomer contains a predetermined ratio of hydrocarbon-based synthetic oil.

Therefore, the mechanical strength (specifically, the tensile strength and the elongation at the time of cutting) can be improved.

Specifically, the tensile strength of the polyurethane elastomer (based on JIS K7312 (1996)) is preferably, for example, 20 MPa or more when the polyol component contains 1,4-bis (2-hydroxyethoxy) benzene. Is 25 MPa or more, and usually 50 MPa or less, and when the polyol component does not contain 1,4-bis (2-hydroxyethoxy) benzene, for example, 10 MPa or more, and For example, it is less than 20 MPa.

The elongation at cutting of the polyurethane elastomer (according to JIS K7312 (1996)) is, for example, 500% or more, preferably 550% or more, and for example, 700% or less.

The tear strength of the polyurethane elastomer (according to JIS K7312 (1996)) is, for example, 50 N / mm or more when the polyol component contains 1,4-bis (2-hydroxyethoxy) benzene. Further, for example, when it is 70 N / mm or less and the polyol component does not contain 1,4-bis (2-hydroxyethoxy) benzene, it is, for example, 35 N / mm or more, and for example, 50 N. It is less than / mm.

Since such a polyurethane elastomer is excellent in solvent resistance and mechanical strength (specifically, tensile strength and elongation at cutting), it can be suitably used for, for example, a screen printing squeegee.

In the above description, the hydrocarbon-based synthetic oil is previously added to the polyol composition together with the polyol component, but the present invention is not limited to this, and for example, the hydrocarbon-based synthetic oil is previously added to the polyol composition. Instead, the polyol component, the isocyanate component, and the hydrocarbon-based synthetic oil may be mixed at the same time.

Specific numerical values such as the compounding ratio (content ratio), physical property values, and parameters used in the following description are the compounding ratios (content ratio) corresponding to those described in the above-mentioned "Form for carrying out the invention". ), Physical property values, parameters, etc., can be replaced with the upper limit value (value defined as "less than or equal to" or "less than") or the lower limit value (value defined as "greater than or equal to" or "excess"). it can. In addition, unless otherwise specified in the following description, "part" and "%" are based on mass.
1. 1. Details of Ingredients Each ingredient used in each Example and each Comparative Example is described below.
LSI-990: Carbodiimide derivative of diphenylmethane diisocyanate, trade name "Cosmonate LSI-990", isocyanate group concentration 29.5% by mass, U-6230 manufactured by Mitsui Chemicals, Inc .: Reaction product of succinic acid and polyhydric alcohol. Polyester polyol, OH value 37.3 mgKOH / g, trade name "Takelac U-6230", BHEB manufactured by Mitsui Chemicals, Inc .: 1,4-bis (2-hydroxyethoxy) benzene LX004: ethylene propylene copolymer, moving at 100 ° C. Viscosity 40 mm ² / s, trade name "Lucant LX004", Mitsui Chemicals LX010: ethylene propylene copolymer, kinematic viscosity at 100 ° C 100 mm ² / s, trade name "Lucant LX010", Mitsui Chemicals LX020: ethylene propylene Copolymer, kinematic viscosity at 100 ° C. 150 mm ² / s, trade name "Lucant LX020", Mitsui Chemicals Co., Ltd. LX100: ethylene propylene copolymer, kinematic viscosity at 100 ° C. 600 mm ² / s, trade name "Lucant LX100", Mitsui Chemicals Co., Ltd. LX200: Ethylene propylene copolymer, kinematic viscosity at 100 ° C. 1100 mm ² / s, trade name "Lucant LX200", Mitsui Chemicals Co., Ltd. P-450: hydrocarbon synthetic oil, trade name "Disparon P-450" , Kusumoto Kasei Co., Ltd. BYK-088: Antifoaming agent, trade name "BYK-088", manufactured by Big Chemie Japan Co., Ltd. 2. Production of Polyurethane Elastomer Example 1
6 parts by mass of BHEB, 100 parts by mass of U-6230 (polyester polyol which is a reaction product of succinic acid and polyhydric alcohol), and 0.01 part by mass of LX010 were mixed and heated at 120 ° C. After confirming that BHEB was completely dissolved, further stirring was performed to obtain a polyol composition.

Next, dibutyltin dilaurate was added to this polyol composition as a urethanization catalyst so as to be 10 ppm with respect to U-6230.

Next, while maintaining 120 ° C., LSI-990 (carbodiimide derivative of diphenylmethane diisocyanate) was added to the polyol composition so that the equivalent ratio (NCO / OH) was 0.95, mixed and stirred, and the polyurethane was mixed. An elastomer composition was obtained.

Then, this polyurethane elastomer composition was injected into a molding mold preheated to 110 ° C. in advance. Then, this molding was placed in a heating furnace and heated at 110 ° C. for 1 hour (primary curing). After heating, the mold was removed, and the mixture was further heated at 110 ° C. for 15 hours (secondary curing). As a result, a polyurethane elastomer was obtained.

Example 2 to Example 12, Comparative Example 1 to Comparative Example 4
A polyurethane elastomer was obtained by treating in the same manner as in Example 1 except that the formulation was changed according to the description in Table 1.

In Comparative Example 3, LX010 was phase-separated in U-6230.

Further, in Comparative Example 4, BYK-088 was phase-separated in U-6230.
3. 3. Evaluation The following evaluations were performed on the polyurethane elastomers of each example and each comparative example.

<Shore A hardness>
Shore A hardness was measured according to JIS K7312 (1996). The results are shown in Table 1.

<Tensile strength (MPa)>
According to the physical test method (JIS K7312 (1996)) of the thermosetting polyurethane elastomer molded product, the tensile strength was measured at a tensile speed of 500 mm / min using a No. 3 dumbbell-shaped test piece. The results are shown in Table 1.

<Elongation when cutting (%)>
According to the physical test method (JIS K7312 (1996)) of the thermosetting polyurethane elastomer molded product, the elongation at the time of cutting was measured at a tensile speed of 500 mm / min using a No. 3 dumbbell-shaped test piece. The results are shown in Table 1.

<Tear strength (N / mm)>
According to the physical test method (JIS K7312 (1996)) of the thermosetting polyurethane elastomer molded product, the tear strength was measured at a tear speed of 500 mm / min using an angle type test piece without a notch. The results are shown in Table 1.

<Presence / absence of bleed>
The presence or absence of bleeding on the surface of the polyurethane elastomer, which was removed from the mold having a size of about 30 cm × 10 cm × thickness 2 mm, was visually confirmed. The results are shown in Table 1.

Claims (4)

It contains a reaction product of a polyisocyanate component and a polyol component including a polyester polyol, and a hydrocarbon-based synthetic oil.
The polyester polyol is a reaction product of a polybasic acid and a polyhydric alcohol.
The polybasic acid contains succinic acid and contains
A polyurethane elastomer characterized in that the blending ratio of the hydrocarbon-based synthetic oil is 0.001 part by mass or more and 0.2 part by mass or less with respect to 100 parts by mass of the polyester polyol. The polyurethane elastomer according to claim 1, wherein the hydrocarbon-based synthetic oil is an ethylene-propylene copolymer. The polyurethane elastomer according to claim 1 or 2, wherein the kinematic viscosity of the hydrocarbon-based synthetic oil at 100 ° C. is 150 mm ² / s or less. The polyurethane elastomer according to any one of claims 1 to 3, wherein the polyol component contains 1,4-bis (2-hydroxyethoxy) benzene.