JP3341274B2 - Two-component polyurethane elastomer composition for casting and method for producing polyurethane elastomer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a two-component polyurethane elastomer composition for casting and a method for producing a polyurethane elastomer. More specifically, the present invention relates to a polyurethane elastomer composition for two-pack casting comprising a polyester-based isocyanate group-terminated prepolymer and a specific polyol mixture as a curing agent, and which has excellent physical strength and weather resistance.

[0002]

2. Description of the Related Art In general, a polyurethane elastomer for casting is prepared by reacting, for example, tolylene diisocyanate with a polyol to form an NCO-terminated prepolymer, and then using 4,4'-methylenebis (2-chloroaniline), 4,4'-diaminodiphenylmethane, 4,4 '
-Diaminodiphenyl ether or the like is used. Polyurethane elastomer obtained using such a composition has discoloration due to light due to aromatic polyisocyanate, while amine of curing agent is in contact with air due to insufficient storage and handling. Oxidation and decomposition by heating and melting proceed to increase the degree of coloration, which greatly affects the color tone and degree of coloration of the molded product, and its use is restricted. JP-A-6-3
In JP 06141, dicyclohexylmethane diisocyanate is used as a part of polyisocyanate and reacted with polyether polyol to form an NCO-terminated prepolymer. The object of the present invention is to improve workability and obtain excellent physical properties, but has not yet improved weather resistance.

[0003]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies to improve weather resistance in the conventional casting technique, and as a result, as a polyisocyanate for a polyester-based NCO-terminated prepolymer. Hexamethylene diisocyanate isocyanurate ring-containing modified product (hereinafter referred to as HD
I), or a polyester-based NCO-terminated prepolymer comprising a uretdione ring and isocyanurate ring-containing modified hexamethylene diisocyanate (hereinafter abbreviated as uretdione / nurate modified HDI) and a polyester polyol. The present invention was found to be able to be improved by using a specific polyol mixture as a polymer component and a curing agent, and reached the present invention.

[0004]

That is, the present invention relates to a polyurethane elastomer composition comprising (A) a polyester-based NCO-terminated prepolymer component comprising a HDR-nurate-modified polyisocyanate and a polyester polyol as a polyisocyanate; ) 1,4-bis (2
-Hydroxyethoxy) benzene (hereinafter abbreviated as BHEB) and trimethylolpropane (hereinafter abbreviated as TMP)
And a polyurethane elastomer composition for two-pack casting. The present invention relates to a polyurethane elastomer composition comprising (A) a polyester-based isocyanate-terminated prepolymer component comprising a uretdione / nurate modified product of HDI as a polyisocyanate and a polyester polyol, and (B) BH as a curing agent.
A two-component cast polyurethane elastomer composition comprising EB and TMP. The present invention
Using a polyurethane elastomer composition for liquid casting,
The components (A) and (B) are mixed with stirring at a molar ratio of NCO group / active hydrogen group of 0.8 to 1.2, and injected into a mold.
A method for producing a polyurethane elastomer, which is characterized by molding.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As the polyisocyanate constituting the polyester-based NCO group-terminated prepolymer, which is the component (A) of the present invention, a modified HDI of HDI or H
A uretdione / nurate modified form of DI is used in combination. As other polyisocyanates, isophorone diisocyanate, xylylene diisocyanate, lysine diisocyanate, tetramethyl xylylene diisocyanate and the like, and modified products thereof can be used in combination. These can be used alone or as a mixture of two or more.
The uretdione ring-containing compound of HDI may be used alone or in combination.

The modified HDR of HDI constituting the component (A) of the present invention is hexamethylene diisocyanate (hereinafter abbreviated as HDI) or a polyol adduct of HDI in which a part of the NCO group of HDI is polyol-added. , And an isocyanurate-forming catalyst and, if necessary, a co-catalyst, and then an isocyanurate-forming reaction at about 50 to 100 ° C. In this case, not more than 20% by weight of the NCO group of HDI was reacted with the polyol to obtain a polyol adduct of HDI. The polyol for obtaining the polyol adduct of HDI has a molecular weight of 3000.
Hereinafter, those having a functionality of 2 to 3, for example, 1,3-butanediol, dipropylene glycol, 1,6-hexane glycol, 3-methyl-1,5-pentanediol, neopentyl glycol (hereinafter abbreviated as NPG) ), 2, 2
-Diethyl-1,3-propanediol, 2-ethyl-
Examples thereof include 1,3-hexanediol, 2-n-butyl-2-ethyl-1,3-propanediol (hereinafter abbreviated as 2-BEPG), polyester polyol, and polyether polyol. These can be used alone or as a mixture of two or more.

The catalyst for obtaining the modified HDI includes propionic acid, butyric acid, valeric acid, caproic acid, heptanoic acid, caprylic acid, pelargonic acid, capric acid, undecylic acid and potassium or sodium salts of these branched fatty acids. Is mentioned. As a co-catalyst that can be used in combination with the catalyst, a phenolic hydroxy compound (phenol, cresol, etc.), an alcoholic hydroxy compound (ethanol, cyclohexanol, etc.), or a tertiary amine (triethylamine, methylpiperidine, etc.) is used. be able to. The reaction proceeds easily with this co-catalyst. The amount of the catalyst used is 0.001 to 0.25% by weight based on the polyisocyanate,
0.2% by weight. In addition, a reaction terminator can be used. As the terminating agent, for example, phosphoric acid, sulfuric acid, or the like can be used, and the used amount is 0.5 to 5.0 times the catalyst equivalent.

The uretdione / nurate modified form of HDI used in the present invention can be obtained by converting HDI or a part of the NCO group of HDI into a polyol adduct as required, followed by isocyanuration. This HDI polyol adduct is obtained by converting a part (20% by weight or less) of all NCO groups into a polyol adduct, and then uretdione-formation and isocyanuration-formation. The polyols that can be used here are
The polyol used for obtaining the nurate-modified HDI can be used. Effective catalysts for obtaining a uretdione / nurate modified form of HDI include triethylphosphine, dibutylethylphosphine, tri-n
-Phosphines such as propylphosphine, trioctylphosphine, and triamylphosphine. The reaction can be carried out in the same manner as in the isocyanuration. The reaction mixture thus obtained is obtained, for example, by removing unreacted HDI by thin-film distillation.
The uretdione / nurate modified form of HDI has a ratio of the isourenurate cyclic trimer of 11 to 40% by weight to the uretdione dimer content of 20 to 60% by weight.
The NCO group content is 17 to 25% by weight. In addition, the uretdione dimer content and the isouannulate cyclic trimer content were determined from a calibration curve based on the area percentage of each peak obtained by gel permeation chromatography using differential refractometer detection.

[0009] As described above, the nurate modified form of HDI and HD
By adding a polyol to HDI, the uretdione / nurate compound of I allows the isocyanurate, uretdione, isocyanurate, etc. reaction to proceed easily. In addition, by using such a polyisocyanate, the compatibility of all components for obtaining an elastomer is improved, and a molded article exhibiting more excellent performance can be obtained.

Preferred polyisocyanates used for obtaining the component (A) of the present invention include compounds obtained by adding a polyol to HDI to contain an isocyanurate ring.
Or a compound obtained by adding a polyol to HDI to contain a uretdione ring and an isocyanurate ring.

As the polyester polyol constituting the polyester-based isocyanate group-terminated prepolymer which is the component (A) of the present invention, ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl -1,5-pentanediol, 1,6-hexanediol, neopentyl glycol (hereinafter abbreviated as NPG), diethylene glycol,
One or more kinds of 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, decamethylene glycol and the like, and malonic acid, maleic acid, succinic acid, adipic acid, glutaric acid, pimelic acid, sebacic acid, oxalate Examples thereof include polyester polyols from one or more of acids, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, and the like, and polycaprolactone polyols obtained by ring-opening polymerization of lactones. Preferred polyester polyols are poly (ethylene adipate) diol, poly (butylene adipate) diol, poly (ethylene butylene adipate) diol having a molecular weight of 800-3500, and preferably having a molecular weight of 1000-3000, and the like.

The preparation of the polyester-based NCO group-terminated prepolymer, which is the component (A) of the present invention, is carried out at a molar ratio of NCO group / hydroxyl group within the range of 1.3 to 10.0. Preferably, it is 1.6 to 6.0. The reaction between the polyisocyanate and the polyester polyol is carried out at a reaction temperature of 50 to 1
Polyester NC at 00 ° C., reaction time 2.5 to 6 hours
An O-group terminated prepolymer can be obtained. The NCO group content of the prepolymer is between 3.0 and 8.0% by weight.

As the curing agent of the component (B) of the present invention, B
Use HEB and TMP. The usage ratio of BHEB to TMP is from 95: 5 to 10:90 (molar ratio), preferably from 90:10 to 20:80 (molar ratio). This ratio affects various properties of the elastomer such as hardness, tensile strength, and compression strain. Therefore, by freely changing the ratio, it is possible to obtain an elastomer that meets the required characteristics.

A catalyst can be added to BHEB and TMP constituting the component (B) of the present invention, if necessary. Examples of the catalyst include tertiary amines such as triethylenediamine and dimethylethanolamine, and metal compounds such as dibutyltin dilaurate.

The components (A) and (B) of the present invention have an NCO group contained in the urethane prepolymer and an active hydrogen group concentration of the component (B) in a molar ratio of NCO group / active hydrogen group of 0.8.
１．２1.2. If necessary, a reaction catalyst, an additive, and the like may be used. For casting, the (A) / (B) mixture is poured into a preheated mold, and primary crosslinking is performed at a temperature of 70 to 160 ° C. Next, if necessary, secondary crosslinking is performed at 100 to 170 ° C., and after aging, a urethane elastomer is obtained. The resulting urethane elastomer can be used in various fields,
For example, it is particularly useful for rolls, tires, pipes, and the like.

[0016]

EXAMPLES The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples. “Parts” and “%” in the examples indicate “parts by weight” and “% by weight”, respectively.

Reference Example 1 (Synthesis of HDI Modified Product)
Using 0.1 part of potassium caprate and 0.1 part of phenol as a co-catalyst, an isocyanuration reaction was carried out at 50 ° C. for 5 hours, and 0.07 part of phosphoric acid was added as a terminator,
The reaction was completed. Next, unreacted HDI is distilled off to remove HDI.
Was obtained. NCO group content 22.0%, viscosity 195
It was 0 cPs / 25 ° C.

Reference Example 2 (Synthesis of HDI Modified Product) 2-BEPG was added to 100 parts of HDI.
1.0 part was added and reacted at 90 ° C. for 3 hours to obtain a polyol adduct of HDI. Next, 0.1 part of potassium caprate and 0.1 part of phenol as a co-catalyst were used.
The isocyanurate-forming reaction was carried out for an hour, and 0.07 parts of phosphoric acid was added as a terminator to terminate the reaction. Next, unreacted HDI was distilled off to obtain a modified HDI. The NCO group content was 21.1% and the viscosity was 2850 cPs / 25 ° C.

Reference Example 3 (Synthesis of modified uretdione / nurate of HDI) HD
To 300 parts of I, 0.3 parts of triblephosphine was added, and the reaction was carried out at 90 ° C. for 3 hours. 0.33 parts of methyl paratoluenesulfonate was added as a terminator to terminate the reaction. Next, unreacted HDI was distilled off to obtain a modified uretdione / nurate HDI. NCO group content 22.0%, viscosity 10
It was 0 cPs / 25 ° C. HDI dimer content 43
% And the HDI trimer content was 31%.

Reference Example 4 (Synthesis of uretdione / nurate modified form of HDI) HD
The reaction was carried out in the same manner as in Reference Example 2 using 300 parts of IPG, 6.4 parts of NPG, and 0.4 part of tributylphosphine.
The reaction was terminated by adding 0.33 parts of methyl paratoluenesulfonate as a terminator. Next, unreacted HDI was distilled off to obtain a modified uretdione / nurate HDI.
The NCO content was 21.1% and the viscosity was 150 cPs / 25 ° C. HDI dimer was 32%, and HDI trimer was 28%.

Examples 1-2 Preparation of Polyurethane Elastomer Composition and Elastomer As a polyisocyanate, the HDR-nullated modified product of Reference Example 1 and poly (ethylene adipate) diol (average molecular weight 1500, hydroxyl value 74.8) were used. An elastomer composition comprising a polyester-based NCO group-terminated prepolymer component and BHEB and TMP as curing agents was obtained.

Production of Elastomer The modified HDI nullite of Reference Example 1 was charged into a four-necked flask as a polyisocyanate under the conditions shown in Table 1 and then heated to 50 ° C.
Held. Next, the poly (ethylene adipate) diol was reacted under the conditions of Table 1 while stirring under a nitrogen stream to obtain a transparent and viscous prepolymer (A).
After adding BHEB and TMP as components (B) to the thus obtained prepolymer (A) and sufficiently stirring the mixture until the mixture becomes completely uniform, the mixture is defoamed at a reduced pressure of 10 Torr or less until the foaming stops. Was. This mixture was added to 130
Inject into a centrifugal molding machine preheated to
1 hour at 120 ° C., and the obtained plate-like polyurethane is heated to 120 ° C.
After secondary cross-linking for 2 hours, further aging at room temperature for 1 week,
An elastomer was obtained. The formulations and results are shown in Table 1.

Examples 3 to 4 Production of polyurethane elastomer composition and elastomer As the polyisocyanate, the HDR nurate modified product of Reference Example 2 and poly (ethylene adipate) diol (average molecular weight 3000, hydroxyl value 37.4) were used. An elastomer composition comprising a polyester-based NCO group-terminated prepolymer component and BHEB and TMP as curing agents was obtained. Production of Elastomer As a polyisocyanate, the nurate-modified HDI of Reference Example 2 was charged into a four-necked flask under the conditions shown in Table 1, and 50
C. was maintained. Next, the poly (ethylene adipate) diol was reacted under the conditions of Table 1 while stirring under a nitrogen stream to obtain a transparent and viscous prepolymer (A).
After adding BHEB and TMP as components (B) to the thus obtained prepolymer (A) and sufficiently stirring the mixture until the mixture becomes completely uniform, the mixture is defoamed at a reduced pressure of 10 Torr or less until the foaming stops. Was. This mixture was added to 130
Inject into a centrifugal molding machine preheated to
C. for 1 hour, and the obtained plate-like polyurethane was
After secondary cross-linking at 2 ° C. for 2 hours, the mixture was further aged at room temperature for 1 week to obtain an elastomer. The prescription and results are shown in Table 1.

Example 5 Production of Polyurethane Elastomer Composition and Elastomer Polyester comprising, as polyisocyanate, the nurate-modified HDI of Reference Example 2 and poly (butylene adipate) diol (average molecular weight: 3,000, hydroxyl value: 37.4) An elastomer composition comprising a system NCO-terminated prepolymer component and BHEB and TMP as a curing agent was obtained. Production of Elastomer As a polyisocyanate, the HDR nurate modified product of Reference Example 2 was charged into a four-necked flask under the conditions shown in Table 1, and 50
C. was maintained. Next, the poly (ethylene adipate) diol was reacted under the conditions of Table 1 while stirring under a nitrogen stream to obtain a transparent and viscous prepolymer (A).
After adding BHEB and TMP as components (B) to the thus obtained prepolymer (A) and sufficiently stirring the mixture until the mixture becomes completely uniform, the mixture is defoamed at a reduced pressure of 10 Torr or less until the foaming stops. Was. This mixed solution is
Inject into a centrifugal molding machine preheated to
C. for 1 hour, and the obtained plate-like polyurethane was
After secondary cross-linking at 2 ° C. for 2 hours, the mixture was further aged at room temperature for 1 week to obtain an elastomer. The formulations and results are shown in Table 2.

Examples 6 to 7 Production of polyurethane elastomer composition and elastomer As the polyisocyanate, the uretdione / nurate modified product of HDI of Reference Example 3 and poly (ethylene adipate)
An elastomer composition comprising a polyester-based NCO-terminated prepolymer component comprising diol (average molecular weight 1500, hydroxyl value 74.8) and BHEB and TMP as a curing agent was obtained. Production of Elastomer The modified uretdione / nurate of HDI of Reference Example 3 was charged into a four-necked flask as a polyisocyanate under the conditions shown in Table 2, and kept at 50 ° C. Next, poly (ethylene adipate) diol was reacted under stirring in a nitrogen stream under the conditions shown in Table 2 to obtain a transparent and viscous prepolymer (A). Prepolymer (A) thus obtained
After adding BHEB and TMP as components (B) and stirring sufficiently until the mixture becomes completely uniform, a vacuum pump 10 Torr
Defoaming was performed at the following degree of reduced pressure until the foaming stopped. This mixture was poured into a centrifugal molding machine preheated to 130 ° C., primary curing was performed at 130 ° C. for 1 hour, and the obtained plate-like polyurethane was secondarily crosslinked at 120 ° C. for 2 hours, and then further cured at room temperature for 1 hour. After aging for a week, an elastomer was obtained. The formulations and results are shown in Table 2.

Examples 8 to 9 Production of polyurethane elastomer compositions and elastomers As polyisocyanates, uretdione / nurate modified HDI of Reference Example 4 and poly (ethylene adipate)
An elastomer composition comprising a polyester-based NCO-terminated prepolymer component comprising diol (average molecular weight 3000, hydroxyl value 37.4) and BHEB and TMP as a curing agent was obtained. Production of Elastomer As a polyisocyanate, the uretdione / nurate modified HDI of Reference Example 4 was charged into a four-necked flask under the conditions shown in Table 2, and kept at 50 ° C. Next, poly (ethylene adipate) diol was reacted under stirring in a nitrogen stream under the conditions shown in Table 2 to obtain a transparent and viscous prepolymer (A). Prepolymer (A) thus obtained
After adding BHEB and TMP as components (B) and stirring sufficiently until the mixture becomes completely uniform, a vacuum pump 10 Torr
Defoaming was performed at the following degree of reduced pressure until the foaming stopped. This mixture was poured into a centrifugal molding machine preheated to 130 ° C., primary curing was performed at 130 ° C. for 1 hour, and the obtained plate-like polyurethane was secondarily crosslinked at 120 ° C. for 2 hours, and further at room temperature for 1 week. After aging, an elastomer was obtained. The formulations and results are shown in Table 2.

Example 10 Production of Polyurethane Elastomer Composition and Elastomer As the polyisocyanate, the uretdione / nurate modified product of HDI of Reference Example 4 and poly (butylene adipate) were used.
An elastomer composition comprising a polyester-based NCO-terminated prepolymer component comprising diol (average molecular weight 3000, hydroxyl value 37.4) and BHEB and TMP as a curing agent was obtained. Production of Elastomer As a polyisocyanate, the uretdione / nurate modified HDI of Reference Example 4 was charged into a four-necked flask under the conditions shown in Table 2, and kept at 50 ° C. Next, poly (butylene adipate) diol was reacted under stirring in a nitrogen stream under the conditions shown in Table 2 to obtain a transparent and viscous prepolymer (A). Prepolymer (A) thus obtained
After adding BHEB and TMP as components (B) and stirring sufficiently until the mixture becomes completely uniform, a vacuum pump 10 Torr
Defoaming was performed at the following degree of reduced pressure until the foaming stopped. This mixture was poured into a centrifugal molding machine preheated to 130 ° C., primary curing was performed at 130 ° C. for 1 hour, and the obtained plate-like polyurethane was secondarily crosslinked at 120 ° C. for 2 hours, and further at room temperature for 1 week. After aging, an elastomer was obtained. The formulations and results are shown in Table 2.

Example 11 Production of Polyurethane Elastomer Composition and Elastomer As the polyisocyanate, the uretdione / nurate modified HDI of Reference Example 3 and poly (ethylenebutylene adipate) diol (ethylene glycol: butylene glycol = 1: 1 mol, Average molecular weight 1500, hydroxyl value 7
4.8) to obtain an elastomer composition comprising a polyester-based NCO group-terminated prepolymer component consisting of BHEB and TMP as a curing agent. Production of Elastomer The modified uretdione / nurate of HDI of Reference Example 3 was charged into a four-necked flask as a polyisocyanate under the conditions shown in Table 2, and kept at 50 ° C. Next, a poly (ethylene butylene adipate) diol was reacted with stirring under a nitrogen stream under the conditions shown in Table 2 to obtain a transparent and viscous prepolymer (A). After adding BHEB and TMP as components (B) to the prepolymer (A) thus obtained and stirring the mixture thoroughly until it becomes completely uniform, the vacuum pump 10
Defoaming was performed at a reduced pressure of Torr or less until foaming stopped. This mixture was poured into a centrifugal molding machine preheated to 130 ° C., primary curing was performed at 130 ° C. for 1 hour, and the obtained plate-like polyurethane was secondarily crosslinked at 120 ° C. for 2 hours.
Further aging was performed at room temperature for one week to obtain an elastomer. The formulation is shown in Table 2 and the results are shown in Table 2. The formulations and results are shown in Table 2.

Comparative Example 1 Production of Elastomer As a polyisocyanate, tolylene diisocyanate (hereinafter abbreviated as TDI) was charged into a four-necked flask and kept at 50 ° C. Then, poly (ethylene adipate) diol (average molecular weight 1500, hydroxyl value 74.
8) was reacted under a nitrogen stream with stirring under the conditions and conditions shown in Table 3 to obtain a transparent and viscous prepolymer (A). The prepolymer (A) thus obtained is added to (B)
After adding 4,4'-methylenebis (2-chloroaniline) (hereinafter abbreviated as MOCA) as a component and stirring sufficiently until the mixture becomes transparent, defoaming is performed at a reduced pressure of a vacuum pump of 10 Torr or less until foaming stops. Was. This mixture is
Inject into a centrifugal molding machine preheated to 30 ° C.
The reaction was carried out at 30 ° C. for 1 hour.
After secondary crosslinking at 0 ° C. for 2 hours, the mixture was further aged at room temperature for 1 week to obtain an elastomer. The formulations and results are shown in Table 3.

Comparative Example 2 Production of Elastomer In Comparative Example 1, diphenylmethane diisocyanate (hereinafter abbreviated as MDI) was used instead of TDI, and poly (ethylene adipate) diol (average molecular weight 150
Poly (ethylene adipate) diol (average molecular weight 3000, hydroxyl value 3)
7.4), and an elastomer was obtained in the same manner as in Comparative Example 1, except that 1,4-butanediol was used instead of MOCA. The formulations and results are shown in Table 3.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[Explanation of Table] (1) Heat resistance After heating the sample in a oven at 120 ° C. for 400 hours, a change in the state was observed and evaluated in five steps. Grade 5: No change at all on the surface Grade 4: Change slightly observed but not noticeable Grade 3: Change slightly but noticeable Class 2: Change slightly remarkable Class 1: Marked change (2 ) Weather Resistance Using a sunshine weatherometer, the discoloration state of the surface was observed after 400 hours (without rainfall conditions) while maintaining the temperature of the black panel at 80 to 83 ° C, and evaluated on a scale of 1 to 5. Grade 5: No change on the surface. Grade 4: A slight change is observed but not noticeable. Grade 3: A change is slight but noticeable. Grade 2: A change is slightly remarkable.

[0035]

The polyurethane elastomer obtained according to the present invention has good casting workability without deteriorating general physical properties such as hardness, tensile strength, elongation, and compression strain, and has heat resistance, Shows excellent performance such as weather resistance. Especially H
By containing an isocyanurate ring of DI, excellent heat resistance, weather resistance, and the like can be obtained.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-316618 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08G 18/10 C08G 18/28-18 / 32 C08G 18/65-18/66 C08G 18/79

Claims (3)

(57) [Claims] 1. A polyurethane elastomer composition comprising: (A) a polyester-based NCO-terminated prepolymer component comprising a modified isocyanurate ring-containing hexamethylene diisocyanate as a polyisocyanate and a polyester polyol; , 4-
A two-component polyurethane elastomer composition for casting comprising bis (2-hydroxyethoxy) benzene and trimethylolpropane. 2. A polyurethane elastomer composition comprising: (A) a polyester-based NCO-terminated prepolymer component comprising a polyester polyol comprising a modified uretdione ring and isocyanurate ring-containing hexamethylene diisocyanate as a polyisocyanate; and (B) curing. 1. A two-component polyurethane elastomer composition for casting comprising: 1,4-bis (2-hydroxyethoxy) benzene and trimethylolpropane as agents. 3. The polyurethane elastomer composition for two-component casting according to claim 1, wherein the molar ratio of NCO group / active hydrogen group of component (A) and component (B) is 0.8 to 3.
1.2. A method for producing a polyurethane elastomer, which comprises mixing, stirring and injecting into a mold, followed by molding.