JP4466006B2 - Polyurethane elastomer-forming composition, polyurethane elastomer molded product and method for producing the same - Google Patents

Description

  The present invention relates to a polyurethane elastomer-forming composition, a polyurethane elastomer molding and a method for producing the same, and more specifically, a two-component curable novel polyurethane elastomer-forming composition, which is obtained by this polyurethane elastomer-forming composition. The present invention relates to a polyurethane elastomer molded article having excellent mechanical properties under high temperature conditions, and a method for producing the polyurethane elastomer molded article.

  Thermoplastic polyurethane elastomer moldings are suitably used as parts for industrial equipment that require elasticity.

  The thermosetting polyurethane elastomer molding is prepared by mixing the main component consisting of the isocyanate component and the curing agent consisting of the active hydrogen component with the mixing head of the casting machine, and injecting the resulting mixture into the mold. It can manufacture by carrying out heat hardening (urethanization reaction) of the said liquid mixture within.

  Here, as an isocyanate component for forming a thermosetting polyurethane elastomer, an isocyanate group (NCO group) -terminated urethane prepolymer obtained by reacting diphenylmethane diisocyanate (MDI) and a polyol is suitably used. As the active hydrogen component, a mixture of 1,4-butanediol (1,4-BD) and trimethylolpropane (TMP) [mixing ratio = 75: 25 to 55:45 (mass)] is preferably used. .

  However, since the molded product obtained as described above does not have sufficient mechanical strength (tensile strength, tear strength) and wear resistance, when it is used as a part of industrial equipment, it is relatively short-term. In the meantime, the parts are broken due to breakage, cracks, wear, etc., and the parts need to be replaced.

  In order to solve the above problems, the present inventors have obtained an NCO group terminal obtained by reacting an adipate-based polyester polyol with MDI as an isocyanate component (main agent) for forming a thermosetting polyurethane elastomer. By using a mixture of urethane prepolymer and isocyanurate ring-containing modified product of hexamethylene diisocyanate (HDI), polyurethane elastomer with high mechanical strength (tensile strength and tear strength) and excellent wear resistance It has been found that a molded product can be obtained, and this has been introduced (see Patent Document 1 below).

  With recent high-speed processing of industrial equipment, etc., the components constituting this have good mechanical properties (tensile) not only at room temperature (5-30 ° C) but also at high temperatures (40-80 ° C). Strength, tear strength, and elongation) are required to be expressed.

  However, conventionally known polyurethane elastomer molded products, including those described in Patent Document 1, cannot exhibit sufficient mechanical properties under high temperature conditions (40 to 80 ° C.). For this reason, when the polyurethane elastomer molded product is mounted on industrial equipment as a component used under such high temperature conditions, defects due to breakage, cracks, wear, etc. occur in a very short time due to the influence of heat. Not only is it necessary to replace the part, but it is impossible or extremely difficult to exhibit the performance required for the part (for example, the desired elasticity).

  As described above, conventionally known polyurethane elastomer moldings cannot be used as components of industrial equipment used under high temperature conditions (parts to which heat is applied from the outside or heat is generated by friction, etc.). Currently.

  In order to improve the mechanical properties (tensile strength, tear strength, elongation) of the molded product under high temperature conditions (40 to 80 ° C.), a curing agent (1,4-BD and In the mixture with TMP), the mixing ratio of TMP (trifunctional) is set small [for example, 1,4-BD: TMP = 100: 0 to 80:20 (mass)], and the crosslinking density of the molded product is set to It can also be lowered.

However, the polyurethane elastomer molded product thus formed cannot have the shape restoration properties (low compression set and low permanent elongation) required for the components of industrial equipment, and such molded product. Is necessary to change the design of industrial equipment, and is not realistic.
JP 2002-356536 A

  The present invention has been made based on the above situation.

  The first object of the present invention is superior in mechanical properties and abrasion resistance under a high temperature condition (40 to 80 ° C.) as compared with a conventionally known polyurethane elastomer molding, and equivalent to a conventionally known polyurethane elastomer molding. It is an object of the present invention to provide a composition capable of forming a polyurethane elastomer constituting a molded product having a shape restoring property (low compression set / low permanent elongation).

  The second object of the present invention is superior in mechanical properties and abrasion resistance under a high temperature condition (40 to 80 ° C.) as compared with a conventionally known polyurethane elastomer molding, and equivalent to a conventionally known polyurethane elastomer molding. An object of the present invention is to provide a polyurethane elastomer molded article having shape restoring properties (low compression set / low permanent elongation).

  The third object of the present invention is to provide a method for producing a polyurethane elastomer molded product capable of producing a molded product having the excellent characteristics as described above.

  As a result of intensive studies by the present inventors in order to achieve the above object, an NCO group-terminated urethane prepolymer obtained by reacting MDI with an adipate polyester polyol and HDI are modified with a short-chain diol ( A urethane prepolymer mixture is prepared by mixing the HDI modified product obtained by prepolymerizing HDI) in a specific ratio, and NCO groups present in the urethane prepolymer mixture in a specific ratio; By subjecting the hydroxyl group of the hydroxyl group-containing compound to a urethanization reaction, it has mechanical strength (particularly high temperature conditions) while having shape recovery properties (low compression set / low permanent elongation) equivalent to those conventionally known. A polyurethane elastomer molded product with significantly improved mechanical strength and abrasion resistance is obtained. Heading, which resulted in the completion of the present invention based on this finding.

The polyurethane elastomer-forming composition according to claim 1 is obtained by reacting (A1) MDI with an adipate-based polyester polyol (hereinafter referred to as “specific NCO group-terminated urethane prepolymer (A1)”). 100 parts by mass and (A2) HDI obtained by prepolymerizing a short-chain diol having 1 to 15 carbon atoms and a number average molecular weight of 300 or less, and substantially uretdione ring and 2 to 30 parts by mass of an HDI modified product comprising an isocyanate group-terminated urethane prepolymer not containing an isocyanurate ring (hereinafter referred to as “specific HDI modified product (A2)”) , and the NCO content in this mixture A main agent (A) composed of a urethane prepolymer mixture having a weight ratio of 4.0 to 20.0% by mass; Characterized by comprising from the one of a hydroxyl group-containing compound containing curing agent (B) even without.

  The polyurethane elastomer-forming composition according to claim 2 comprises a diol (B1) having a number average molecular weight of 300 or less and a triol (B2) having a number average molecular weight of 500 or less as a hydroxyl group-containing compound constituting the curing agent (B). It is characterized by containing.

  The polyurethane elastomer-forming composition according to claim 3 includes a diol (B1) having a number average molecular weight of 300 or less and a triol (B2) having a number average molecular weight of 500 or less as a hydroxyl group-containing compound constituting the curing agent (B), It contains an adipate-based polyester polyol (B3).

  A polyurethane elastomer molded product according to claim 4 is obtained by thermosetting the polyurethane elastomer-forming composition according to any one of claims 1 to 3 in a mold.

  The production method according to claim 5 is a method of preparing the polyurethane elastomer-forming composition according to any one of claims 1 to 3 by mixing the main agent (A) and the curing agent (B); It is characterized by including a step of injecting the obtained composition into a mold and a step of curing the composition by heating in the mold.

  According to the composition of the present invention, the main component (A) and the curing agent (B) constituting the composition are mixed and cured, so that the temperature is higher than that of a conventionally known polyurethane elastomer molded product (40 to 80). Forms a polyurethane elastomer that forms a molded product that has excellent mechanical properties and abrasion resistance at ℃), and has a shape restoration property (low compression set and low permanent elongation) that is equal to or better than that of conventionally known polyurethane elastomer molded products. can do.

  The molded product of the present invention is superior in mechanical properties and wear resistance under a high temperature condition (40 to 80 ° C.) than a conventionally known polyurethane elastomer molded product, and has a shape equal to or more than that of a conventionally known polyurethane elastomer molded product. It has resilience (low compression set / low permanent elongation).

  According to the production method of the present invention, the mechanical properties and wear resistance under high temperature conditions (40 to 80 ° C.) are superior to those of conventionally known polyurethane elastomer moldings, and are equivalent to conventionally known polyurethane elastomer moldings. A molded product having the above shape restoring properties (low compression set and low permanent elongation) can be reliably produced.

Hereinafter, the present invention will be described in detail.
<Polyurethane elastomer forming composition>
The polyurethane elastomer-forming composition of the present invention is a casting composition used for forming a thermosetting polyurethane elastomer (molded product), and comprises a main agent (A), a curing agent (B), Is a two-component curable composition.
<Main agent (A)>
The main agent (A) constituting the composition of the present invention comprises a urethane prepolymer mixture in which a specific NCO group-terminated urethane prepolymer (A1) and a specific HDI modified product (A2) are mixed.

In this urethane prepolymer mixture, MDI used for obtaining a specific NCO group-terminated urethane prepolymer (A1) may be contained.
(1) Specific NCO group-terminated urethane prepolymer (A1):
The specific NCO group-terminated urethane prepolymer (A1) constituting the urethane prepolymer mixture is a reaction product of MDI and an adipate-based polyester polyol.

  Examples of the adipate-based polyester polyol used for obtaining the specific NCO group-terminated urethane prepolymer (A1) include a polyester polyol obtained by polycondensation of a short-chain diol and adipic acid.

  Here, as the short-chain diol subjected to the polycondensation reaction with adipic acid, ethylene glycol (EG), 1,2-propylene glycol (1,2-PG), 1,3-propylene glycol (1, 3-PG), 1,3-butanediol (1,3-BD), 1,4-butanediol (1,4-BD), neopentyl glycol (NPG), 1,6-hexamethylene glycol (1, 6-HG) and the like, and these compounds can be used alone or in combination of two or more.

  The number average molecular weight of the adipate-based polyester polyol is preferably 500 to 4,000, and more preferably 1,000 to 3,000.

  In the specific NCO group-terminated urethane prepolymer (A1), the molar ratio of the NCO group of the former to the hydroxyl group of the latter (NCO group / hydroxyl group) of MDI and adipate polyester polyol is 1.6 to 10. The system can be prepared by reacting at a temperature of 50 to 100 ° C. for 1 to 5 hours.

  The number average molecular weight of the specific NCO-terminated urethane prepolymer (A1) is preferably 420 to 2,000.

Moreover, it is preferable that the NCO content of a specific NCO terminal urethane prepolymer (A1) is 4.2-20.0 mass%.
(2) Specific HDI modified product (A2):
The specific modified HDI (A2) constituting the urethane prepolymer mixture is substantially free of uretdione ring and isocyanurate ring obtained by modifying HDI with a short-chain diol (prepolymerizing HDI). It is a modified product (NCO group-terminated urethane prepolymer).

  A specific HDI modified product (A2) is prepared by reacting an excess amount of HDI with a short-chain diol at a temperature of 70 to 150 ° C. for 1 to 10 hours in the absence of a uretdioneization catalyst and an isocyanuration catalyst. can do. The unreacted HDI remaining in the reaction product is preferably removed by distillation or extraction.

  Suitable short-chain diols that are subjected to reaction with HDI include diols having 1 to 15 carbon atoms. The number average molecular weight of this short chain diol is preferably 300 or less, more preferably 250 or less.

  Specific examples of such short-chain diols include ethanediol, propanediol (including various isomers), butanediol (including various isomers), pentanediol (including various isomers), and hexanediol (including various isomers). ), Heptanediol (including various isomers), octanediol (including various isomers), nonanediol (including various isomers), decanediol (including various isomers), diethylene glycol, hydrogenated bisphenol A, etc. Can be mentioned. Of these, an aliphatic diol having 2 to 6 carbon atoms is particularly preferable.

  When the HDI is modified with a long-chain diol (for example, a diol having 16 or more carbon atoms and a number average molecular weight exceeding 300) in place of the short-chain diol, the finally obtained polyurethane elastomer molded product becomes room temperature. It does not have sufficient mechanical properties (particularly tensile properties) under any of the lower and high temperature conditions (see Comparative Example 5 described later).

The specific HDI modified product (A2) is substantially free of uretdione ring and isocyanurate ring. By using such a specific HDI modified product (A2), compared with the case of using an HDI modified product containing a uretdione ring and / or an isocyanurate ring, the polyurethane elastomer molded product finally obtained has a higher temperature. Mechanical properties (especially tensile properties) under conditions are significantly improved.
(3) Preparation method of urethane prepolymer mixture:
The urethane prepolymer mixture is prepared by mixing the specific HDI modified product (A2) at a ratio of 2 to 30 parts by mass with respect to 100 parts by mass of the specific NCO group-terminated urethane prepolymer (A1).

  When the mixing ratio of the specific HDI modified product with respect to 100 parts by mass of the specific NCO group-terminated urethane prepolymer is less than 2 parts by mass, the finally obtained polyurethane elastomer molded product has mechanical properties under high temperature conditions. The improvement effect and the improvement effect of wear resistance cannot be sufficiently provided. On the other hand, when the mixing ratio exceeds 30 masses, the hardness and mechanical strength of the finally obtained polyurethane elastomer molded product are significantly reduced (see Comparative Example 4 described later).

MDI and a specific HDI modified product (A2) are mixed, an adipate polyester polyol is added to the mixture, and MDI and an adipate polyester polyol are added in the presence of the specific HDI modified product (A2). A urethane prepolymer mixture can also be prepared by a reaction (a formation reaction of a specific NCO group-terminated urethane prepolymer (A1)).
(4) NCO content of urethane prepolymer mixture:
The NCO content of the urethane prepolymer mixture is 4.0 to 20.0% by mass, and preferably 6.0 to 18.0% by mass.

The urethane prepolymer mixture having an NCO content of less than 4.0% by mass has an excessive viscosity, and the flow of the composition during casting of the elastomer-forming composition (mixed solution with a curing agent) containing the urethane prepolymer mixture is low. The properties are significantly reduced, leading to poor defoaming and molding defects. On the other hand, a urethane prepolymer mixture having an NCO content of more than 20.0% by mass significantly deteriorates the property stability during storage and use, resulting in poor molding. When the NCO content of the urethane prepolymer mixture is 4.0 to 20.0% by mass, a molded product suitable as a component for industrial equipment can be obtained.
<Curing agent (B)>
The curing agent (B) constituting the composition of the present invention contains at least one hydroxyl group-containing compound.

  In the curing agent (B), a diol (B1) having a number average molecular weight of 300 or less and a triol (B2) having a number average molecular weight of 500 or less are preferably used as the hydroxyl group-containing compound.

  Examples of the diol (B1) having a number average molecular weight of 300 or less constituting the curing agent (B) include ethylene glycol (EG), diethylene glycol (DEG), 1,2-propylene glycol (1,2-PG), 1,3. -Propylene glycol (1,3-PG), 1,3-butanediol (1,3-BD), 1,4-butanediol (1,4-BD), neopentylglycol (NPG), 1,6 -Hexamethylene glycol (1,6-HG), hydrogenated bisphenol A, etc. can be mentioned, These can be used individually or in combination of 2 or more types. Of these, 1,4-BD is particularly preferred.

  Examples of the triol (B2) having a number average molecular weight of 500 or less constituting the curing agent (B) include glycerin, trimethylolpropane (TMP), hexanetriol, and the like. These may be used alone or in combination of two or more. Can be used. Of these, TMP is particularly preferred.

  Furthermore, you may comprise a hardening | curing agent (B) using a long-chain polyol with the said diol (B1) and the said triol (B2) as a semi one shot prescription.

  As the long-chain polyol constituting the curing agent (B), the adipate-based polyester polyol described above as used for the synthesis of the specific NCO group-terminated urethane prepolymer (A1) is preferable.

  In the curing agent (B), the mass ratio of the diol (B1) to the triol (B2) is usually 75/25 to 55/45.

Moreover, the mass ratio of the total amount of the diol (B1) and the triol (B2) to the long-chain polyol is usually 100/0 to 5/95.
<Polyurethane elastomer molding and production method>
The polyurethane elastomer molded article of the present invention is obtained by thermally curing the composition of the present invention, which is a mixed liquid of the main agent (A) and the curing agent (B), in a mold.

  The production method of the present invention comprises a step of preparing the composition of the present invention by mixing the main agent (A) and the curing agent (B), a step of injecting the obtained composition into a mold, and the composition Curing the product by heating it in a mold.

Hereinafter, specific steps of the production method of the present invention will be described.
(1) Mixing process:
In this step, the main agent (A) and the curing agent (B) are uniformly mixed to prepare the composition of the present invention, which is degassed to remove air (bubbles) entrained during mixing. To do.

  The mixing ratio of the main agent (A) and the curing agent (B) is preferably such that the NCO group / hydroxyl molar ratio is 1.0 to 1.3.

  Moreover, you may mix a urethanization catalyst and an additive with a main ingredient (A) and a hardening | curing agent (B) as needed.

  Here, the urethanization catalyst is not particularly limited, and conventionally known metal catalysts (for example, dibutyltin dilaurate), amine catalysts (for example, triethylenediamine) and the like can be exemplified.

  Examples of the additive include an antioxidant, a defoaming agent, an ultraviolet absorber, and a reaction modifier.

Examples of the mixing method include a mixing method using a mixing head of a casting machine. (2) Casting process:
In this step, a mixed liquid (the composition of the present invention) of the main agent (A) and the curing agent (B) is poured into a mold.

The mold into which the mixed liquid is injected is preferably preheated to about 40 to 150 ° C.
(3) Curing process:
In this step, the mixed liquid (the composition of the present invention) injected into the mold is heated with a urethanization reaction to be cured.

The reaction conditions are a temperature of 40 to 150 ° C. and a time of 2 to 60 minutes.
(4) Demolding process:
In this step, the molded product (molded product of the present invention) obtained by curing is taken out of the mold.

  The molded product thus obtained (polyurethane elastomer molded product of the present invention) has a higher tensile strength, tear strength and higher strength than conventional known molded products, as is apparent from the results of Examples described later. It has high elongation and excellent mechanical properties, as well as excellent wear resistance and shape recovery (low compression set).

  Further, the hardness of the molded product is 45 to 98 ° as measured by a JIS-A type hardness meter, and this value is equivalent to the hardness of a molded product widely used as a part of industrial equipment.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. In the following, “parts” and “%” mean “parts by mass” and “% by mass”, respectively. In the following Examples and Comparative Examples, the following compounds were used as adipate polyester polyols.

(1) “PEA-2000”:
A polyester diol having a number average molecular weight of 2,000 obtained by polycondensation of ethylene glycol and adipic acid.

(2) “PBA-2000”:
A polyester diol having a number average molecular weight of 2,000 obtained by polycondensation of 1,4-BD and adipic acid.

(3) “PHA-2000”:
A polyester diol having a number average molecular weight of 2,000 obtained by polycondensation of 1,6-HG and adipic acid.
[Synthesis Example 1 (Synthesis of specific HDI modified product (A2))]
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas introduction tube, 880 parts of hexamethylene diisocyanate (HDI) and 120 parts of 1,3-butanediol (1,3-BD) were charged. Under a nitrogen atmosphere, the system was reacted at 110 ° C. for 3 hours.

Subsequently, unreacted HDI was removed from the obtained reaction solution by thin film distillation (150 ° C. 0.7 kPa) to obtain a specific HDI modified product (A2) having an NCO content of 19.7%. .
<Example 1>
According to the formulation shown in Table 1 below, 29.8 parts of diphenylmethane diisocyanate (MDI) and 70.1 parts of polyester diol “PEA-2000” are mixed and this system is heated and reacted at 75 ° C. for 3 hours. Thus, a specific NCO group-terminated urethane prepolymer (A1) was prepared. The reaction product [specific NCO group-terminated urethane prepolymer (A1)] is blended with 5.0 parts of the specific HDI modified product (A2) obtained in Synthesis Example 1 to form a urethane prepolymer mixture. The main agent (A) was prepared.

  Here, the NCO content of the specific NCO group-terminated urethane prepolymer (A1) was 7.0%, and the NCO content of the main agent (A) comprising the urethane prepolymer mixture was 7.6%.

  On the other hand, according to the formulation shown in Table 1 below, by mixing 60.0 parts of 1,4-BD, 40.0 parts of TMP, and 0.20 parts of triethylenediamine (catalyst), the hydroxyl value is 1245 KOHmg / g. A mixture of curing agent (B) and catalyst was prepared.

Subsequently, according to the prescription (blending ratio) shown in Table 1 below, the mixture of the main agent (A), the curing agent (B) and the catalyst is mixed with a two-component mixed urethane casting machine, thereby forming the polyurethane elastomer of the present invention. A polyurethane elastomer molding of the present invention is prepared by preparing a composition, injecting the composition into a mold for forming a 2 mm-thick flat sheet preheated to 130 ° C., and curing the composition at 130 ° C. for 1 hour. A product was manufactured, and the molded product was removed from the mold.
<Example 2>
According to the formulation shown in Table 1 below, 29.2 parts of diphenylmethane diisocyanate (MDI) and 70.8 parts of polyester diol “PBA-2000” are mixed and the system is reacted by heating at 75 ° C. for 3 hours. Thus, a specific NCO group-terminated urethane prepolymer (A1) was prepared. By blending 10.0 parts of the specific HDI modified product (A2) obtained in Synthesis Example 1 with this reaction product, a main agent (A) composed of a urethane prepolymer mixture was prepared.

  Here, the NCO content of the specific NCO group-terminated urethane prepolymer (A1) was 6.8%, and the NCO content of the main agent (A) comprising the urethane prepolymer mixture was 8.0%.

  On the other hand, according to the formulation shown in Table 1 below, by mixing 1,5-BD 65.0 parts, TMP 35.0 parts, and triethylenediamine (catalyst) 0.20 parts, the hydroxyl value is 1245 KOHmg / g. A mixture of curing agent (B) and catalyst was prepared.

Subsequently, according to the prescription (blending ratio) shown in Table 1 below, the mixture of the main agent (A), the curing agent (B) and the catalyst is mixed with a two-component mixed urethane casting machine, thereby forming the polyurethane elastomer of the present invention. A polyurethane elastomer molding of the present invention is prepared by preparing a composition, injecting the composition into a mold for forming a 2 mm-thick flat sheet preheated to 130 ° C., and curing the composition at 130 ° C. for 1 hour. A product was manufactured, and the molded product was removed from the mold.
<Example 3>
In accordance with the formulation shown in Table 1 below, 50.9 parts of diphenylmethane diisocyanate (MDI), 32.7 parts of polyester diol “PEA-2000”, and 16.4 parts of polyester diol “PHA-2000” were mixed. Was reacted at 75 ° C. for 3 hours to prepare a specific NCO group-terminated urethane prepolymer (A1). By blending 25.0 parts of the specific HDI modified product (A2) obtained in Synthesis Example 1 with this reaction product, a main agent (A) comprising a urethane prepolymer mixture was prepared.

  Here, the NCO content of the specific NCO group-terminated urethane prepolymer (A1) was 15.0%, and the NCO content of the main agent (A) comprising the urethane prepolymer mixture was 15.9%.

  On the other hand, according to the formulation shown in Table 1 below, 7.5 parts of 1,4-BD, 5.0 parts of TMP, 87.5 parts of polyester diol “PEA-2000”, and 0.02 part of triethylenediamine (catalyst) By mixing, a mixture of a curing agent (B) having a hydroxyl value of 205 KOH mg / g and a catalyst was prepared.

Subsequently, according to the prescription (blending ratio) shown in Table 1 below, the mixture of the main agent (A), the curing agent (B) and the catalyst is mixed with a two-component mixed urethane casting machine, thereby forming the polyurethane elastomer of the present invention. A polyurethane elastomer molding of the present invention is prepared by preparing a composition, injecting the composition into a mold for forming a 2 mm-thick flat sheet preheated to 130 ° C., and curing the composition at 130 ° C. for 1 hour. A product was manufactured, and the molded product was removed from the mold.
<Comparative Example 1>
In accordance with the formulation shown in Table 1 below, 31.4 parts of diphenylmethane diisocyanate (MDI) and 68.6 parts of polyester diol “PEA-2000” are mixed, and this system is heated at 75 ° C. for 3 hours to be reacted. Thus, a specific NCO group-terminated urethane prepolymer (A1) having an NCO content of 7.6% was prepared and used as a main agent.

  On the other hand, according to the formulation shown in Table 1 below, by mixing 60.0 parts of 1,4-BD, 40.0 parts of TMP, and 0.20 parts of triethylenediamine (catalyst), the hydroxyl value is 1245 KOHmg / g. A mixture of curing agent and catalyst was prepared.

Next, according to the prescription (blending ratio) shown in Table 1 below, a polyurethane elastomer-forming composition for comparison is prepared by mixing the mixture of the main agent and the curing agent and the catalyst with a two-component mixed urethane casting machine, This composition is poured into a mold for forming a flat sheet having a thickness of 2 mm, which is preheated to 130 ° C., and heated and cured at 130 ° C. for 1 hour to produce a comparative polyurethane elastomer molded product. The molding was removed from the mold.
<Comparative example 2>
In accordance with the formulation shown in Table 1 below, 32.1 parts of diphenylmethane diisocyanate (MDI) and 68.9 parts of polyester diol “PBA-2000” are mixed and heated to react at 75 ° C. for 3 hours. Thus, a specific NCO group-terminated urethane prepolymer (A1) having an NCO content of 7.9% was prepared and used as a main agent.

  On the other hand, according to the formulation shown in Table 1 below, 1,4-BD 95.0 parts, TMP 5.0 parts, and triethylenediamine (catalyst) 0.20 parts are mixed to give a hydroxyl value of 1245 KOHmg / g. A mixture of curing agent and catalyst was prepared.

Next, according to the prescription (blending ratio) shown in Table 1 below, a polyurethane elastomer-forming composition for comparison is prepared by mixing the mixture of the main agent and the curing agent and the catalyst with a two-component mixed urethane casting machine, This composition is poured into a mold for forming a flat sheet having a thickness of 2 mm, which is preheated to 130 ° C., and heated and cured at 130 ° C. for 1 hour to produce a comparative polyurethane elastomer molded product. The molding was removed from the mold.
<Comparative Example 3>
According to the formulation shown in Table 1 below, 58.9 parts of diphenylmethane diisocyanate (MDI), 27.4 parts of the polyester diol “PEA-2000”, and 13.7 parts of the polyester diol “PHA-2000” are mixed together. Was reacted at 75 ° C. for 3 hours to prepare a specific NCO group-terminated urethane prepolymer (A1) having an NCO content of 18.0%, which was used as a main agent.

  On the other hand, according to the formulation shown in Table 1 below, 1,4-BD 8.1 parts, TMP 4.4 parts, polyester diol "PBA-2000" 58.3 parts, and polyester diol "PHA-2000" 29.2 parts. And 0.02 part of triethylenediamine (catalyst) were mixed to prepare a mixture of a curing agent and a catalyst having a hydroxyl value of 205 KOH mg / g.

Next, according to the prescription (blending ratio) shown in Table 1 below, a polyurethane elastomer-forming composition for comparison is prepared by mixing the mixture of the main agent and the curing agent and the catalyst with a two-component mixed urethane casting machine, This composition is poured into a mold for forming a flat sheet having a thickness of 2 mm, which is preheated to 130 ° C., and heated and cured at 130 ° C. for 1 hour to produce a comparative polyurethane elastomer molded product. The molding was removed from the mold.
<Comparative example 4>
According to the formulation shown in Table 1 below, 41.6 parts of diphenylmethane diisocyanate (MDI) and 58.4 parts of polyester diol “PEA-2000” are mixed, and this system is heated and reacted at 75 ° C. for 3 hours. Thus, a specific NCO group-terminated urethane prepolymer (A1) was prepared. By blending 50.0 parts of the specific HDI modified product (A2) obtained in Synthesis Example 1 with this reaction product, a main agent composed of a urethane prepolymer mixture was prepared.

  Here, the NCO content of the specific NCO group-terminated urethane prepolymer (A1) was 11.5%, and the NCO content of the main agent comprising the urethane prepolymer mixture was 14.2%.

  On the other hand, according to the formulation shown in Table 1 below, 7.5 parts of 1,4-BD, 5.0 parts of TMP, 87.5 parts of polyester diol “PEA-2000”, and 0.02 part of triethylenediamine (catalyst) By mixing, a mixture of a curing agent and a catalyst having a hydroxyl value of 205 KOH mg / g was prepared.

Next, according to the prescription (blending ratio) shown in Table 1 below, a polyurethane elastomer-forming composition for comparison is prepared by mixing the mixture of the main agent and the curing agent and the catalyst with a two-component mixed urethane casting machine, This composition is poured into a mold for forming a flat sheet having a thickness of 2 mm, which is preheated to 130 ° C., and heated and cured at 130 ° C. for 1 hour to produce a comparative polyurethane elastomer molded product. The molding was removed from the mold.

<Comparative Example 5>
In a reaction vessel equipped with a stirrer, thermometer, reflux condenser and nitrogen gas introduction tube, 600 parts of hexamethylene diisocyanate (HDI) and 400 parts of bifunctional polypropylene glycol (long chain diol) having a number average molecular weight of 400 were added. The system was charged and reacted at 110 ° C. for 3 hours under a nitrogen atmosphere.

  Subsequently, unreacted HDI was removed from the obtained reaction solution by thin film distillation (150 ° C. 0.7 kPa) to obtain an HDI modified product having an NCO content of 11.4%.

In accordance with the formulation shown in Table 2 below, instead of the specific HDI modified product (A2), 10.0 parts of the HDI modified product obtained above (HDI modified product with long chain diol) was used (specific NCO group-terminated urethane) A main component comprising a urethane prepolymer mixture was prepared in the same manner as in Example 1 except that it was blended with the prepolymer (A1), and a polyurethane elastomer-forming composition was prepared using this main component. Was used to produce polyurethane elastomer moldings.
<Comparative Example 6>
In a reaction vessel equipped with a stirrer, thermometer, reflux condenser and nitrogen gas introduction tube, 300 parts of hexamethylene diisocyanate (HDI), 0.05 part of potassium caprate (isocyanurate catalyst), and phenol (cocatalyst) 0.3 part) was charged, and this system was subjected to an isocyanuration reaction at 60 ° C. for 4.5 hours under a nitrogen atmosphere. Thereafter, 0.042 part of phosphoric acid (reaction terminator) was added, and a termination reaction was performed at 60 ° C. over 1 hour.

  Next, by removing unreacted HDI from the obtained reaction solution by thin-film distillation (150 ° C. 0.7 kPa), an isocyanurate ring-containing modified product of HDI having an NCO content of 22.0% (hereinafter, referred to as “HDI”) “Isocyanurate ring-containing modified product (i)” was obtained.

In accordance with the formulation shown in Table 2 below, instead of the specific HDI modified product (A2), 5.0 parts of the isocyanurate ring-containing modified product (i) obtained above was used (specific NCO group-terminated urethane prepolymer ( A main component comprising a urethane prepolymer mixture was prepared in the same manner as in Example 1 except that it was blended with A1), and a polyurethane elastomer-forming composition was prepared using this main component, and this composition was used. Thus, a polyurethane elastomer molded product was produced.
<Comparative Example 7>
In a reaction vessel equipped with a stirrer, thermometer, reflux condenser and nitrogen gas introduction tube, 880 parts of hexamethylene diisocyanate (HDI), 120 parts of 1,3-butanediol (1,3-BD), and capric acid 0.05 part of potassium (isocyanuration catalyst) and 0.02 part of phenol (cocatalyst) were charged, and this system was subjected to isocyanuration reaction at 60 ° C. for 4.5 hours in a nitrogen atmosphere. Thereafter, 0.042 part of phosphoric acid (reaction terminator) was added, and a termination reaction was performed at 60 ° C. over 1 hour.

  Next, by removing unreacted HDI from the resulting reaction solution by thin film distillation (150 ° C. 0.7 kPa), an isocyanurate ring-containing modified product of HDI having an NCO content of 18.3% (hereinafter, referred to as “HDI”). “Isocyanurate ring-containing modified product (ii)” was obtained.

In accordance with the formulation shown in Table 2 below, instead of the specific HDI modified product (A2), 8.0 parts of the isocyanurate ring-containing modified product (ii) obtained above was used (specific NCO group-terminated urethane prepolymer ( A main component comprising a urethane prepolymer mixture was prepared in the same manner as in Example 1 except that it was blended with A1), and a polyurethane elastomer-forming composition was prepared using this main component, and this composition was used. Thus, a polyurethane elastomer molded product was produced.

<Evaluation of molded product>
About each of the polyurethane elastomer moldings obtained in Examples 1 to 3 and Comparative Examples 1 to 7, the hardness (according to JIS-A type hardness meter), tensile strength, elongation, tear strength and compression set were measured according to JIS K 7312. Measured according to Here, the hardness test, the tensile test (tensile strength and elongation measurement) and the tear test were carried out in a constant temperature environment at a temperature of 23 ° C. and a temperature of 60 ° C., respectively. The compression conditions in the compression set test were set to a temperature of 70 ° C., a compression rate of 25%, and a compression time of 22 hours.

  Further, the wear resistance of each molded polyurethane elastomer product was evaluated by measuring the wear mass of the test piece with a frictron friction and wear tester (Orientec Co., Ltd.). Here, the measurement conditions were: test piece temperature = about 60 ° C., load = 2.0 kgf, sliding speed = 0.5 m / sec, wear time = 60 minutes, measurement (environment) temperature = 23 ° C.

  These results are shown in Table 3 below.

  The molded product according to the present invention can be suitably used as a component of various industrial equipments that require elasticity (flexibility), and by using the molded product according to the present invention, the durability of the component can be obtained. Can be significantly improved.

The molded product according to the present invention can be mounted on an industrial device as a component used under a high temperature condition, which cannot be handled by a conventionally known molded product, and an industrial device that performs high-speed processing (high temperature New performance can be imparted to industrial equipment that requires the use of elastic parts under conditions, and can contribute to high-speed processing of industrial equipment.

Claims (5)

A two-component curable polyurethane elastomer-forming composition comprising the following main agent (A) and a curing agent (B) containing at least one hydroxyl group-containing compound.
<Main agent (A)>
(A1) 100 parts by mass of an isocyanate group-terminated urethane prepolymer obtained by reacting diphenylmethane diisocyanate (MDI) with an adipate-based polyester polyol;
(A2) Hexamethylene diisocyanate (HDI) is obtained by prepolymerizing a short-chain diol having 1 to 15 carbon atoms and a number average molecular weight of 300 or less, and substantially uretdione ring and isocyanurate ring. 2 to 30 parts by mass of an HDI modified product composed of an isocyanate group-terminated urethane prepolymer not included,
The urethane prepolymer mixture whose NCO content in this mixture is 4.0-20.0 mass%.   The polyurethane elastomer-forming property according to claim 1, comprising a diol (B1) having a number average molecular weight of 300 or less and a triol (B2) having a number average molecular weight of 500 or less as the hydroxyl group-containing compound constituting the curing agent (B). Composition.   A diol (B1) having a number average molecular weight of 300 or less, a triol (B2) having a number average molecular weight of 500 or less, and an adipate polyester polyol (B3) as the hydroxyl group-containing compound constituting the curing agent (B). Item 2. The polyurethane elastomer-forming composition according to Item 1.   A polyurethane elastomer molded article obtained by thermosetting the polyurethane elastomer-forming composition according to any one of claims 1 to 3 in a mold.   The step of preparing the polyurethane elastomer-forming composition according to any one of claims 1 to 3 by mixing the main agent (A) and the curing agent (B), and the obtained composition in the mold A method for producing a molded polyurethane elastomer product, comprising a step of injecting into a mold and a step of curing the composition by heating in a mold.