JP2008133413A - Thermosetting urethane elastomer-forming composition and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that the conventional casting polyurethane elastomer compositions have not satisfied rebound resilience, tension set, and compression set at the same time although good rebound resilience, tension set, and compression set are required in constituting parts of an industrial device such as a compact roll represented by an automotive glass run and a paper feed roll. <P>SOLUTION: The resultant casting polyurethane elastomer composition can possess excellent rebound resilience and tension set by using a casting polyurethane elastomer composition comprising an isocyanate group-terminated prepolymer, a hydroxyl group-containing polymeric polyol as a curing agent, a polyesterpolyol having a molecular weight of 500-2,500 and a nominal average number of functional groups of 3, and a bifunctional glycol having a molecular weight of less than 150. This composition can be used in an automotive glass run, a roll member and the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a polyurethane elastomer composition for casting and a method for producing a polyurethane elastomer using the composition.

Polyurethane elastomer compositions for casting are used for automotive glass runs, small rolls typified by paper feed rolls, and various industrial equipment due to their excellent physical properties, versatility for various applications, economy and adaptability to environmental problems. It can be suitably used as a component.

The polyurethane elastomer composition for casting is required to have high rebound resilience and good permanent elongation and compression set so as to withstand long-term use as the industrial equipment application. However, the polyester polyurethane elastomer composition using 1,4-butanediol (1,4-BD) / trimethylolpropane (TMP) as a chain extender conventionally used has a rebound resilience of 30% or less. Therefore, the required characteristics cannot be satisfied (Comparative Example 7 described later). Further, if the amount of TMP added is reduced for the purpose of improving the resilience, the resilience is improved, but the permanent elongation is deteriorated (Comparative Example 8 described later). Therefore, the 1,4-BD / TMP-based polyurethane elastomer for casting does not satisfy the characteristics required as a subject of the present invention.

Further, as a polyurethane elastomer composition for casting, a rebound resilience of 60 using a curing agent composed of an isocyanate group-terminated prepolymer, a bifunctional polymer polyol, a trifunctional or higher polymer polyol, and a linear low molecular diol is used. Patent document 1 exists as a prior art regarding a cleaning blade of% or more.
However, since the lactone polyol is used as the trifunctional polyol component in the prior art, the impact resilience characteristics are satisfied, but the permanent elongation is poor and the characteristics required for the glass run for automobiles cannot be satisfied. Furthermore, the compression set is also poor, making it difficult to use in the field of small rolls typified by paper feed rolls.

JP 2001-255801 A

  The present invention has been made in view of the above circumstances, and has excellent physical properties such as rebound resilience, permanent elongation, and compression set required in the field of industrial equipment such as automotive glass runs and paper feed rolls. An object is to provide a polyurethane elastomer composition for a mold.

As a result of intensive studies to achieve the above object, the present inventors have satisfied characteristics required as components of industrial equipment such as a glass run for automobiles and a small roll represented by a paper feed roll. Further, a molecular weight comprising an isocyanate group-terminated prepolymer, a polyester polyol having a nominal average functional group number of 2 having a molecular weight of 500 to 2,500, a dibasic acid, a triol having a molecular weight of 500 or less, and a glycol having a molecular weight of 300 or less as a curing agent. By obtaining a polyurethane elastomer composition for casting from a mixture of a polyester polyol having a nominal average functional group number of 3 to 500 to 2500 and a glycol having a molecular weight of less than 150, the resilience, permanent elongation and compression set are good. The inventors have found that a polyurethane elastomer composition for casting is obtained and have reached the present invention.

That is, the present invention is the following I to VII.
I. A polyurethane resin-forming composition comprising an isocyanate prepolymer (A) and a curing agent (B),
(A) is an isocyanate group-terminated prepolymer comprising an organic polyisocyanate (a1) and a hydroxyl group-containing compound (a2),
(B) is a polyester polyol (b1) having a nominal average functional group number of 2 having a molecular weight of 500 to 2,500, a dibasic acid (b21), a triol (b22) having a molecular weight of 500 or less, and a glycol (b23 having a molecular weight of 300 or less) A polyester polyol (b2) having a molecular weight of 500 to 2,500 and a nominal average functional group number of 3 and a glycol (b3) having a molecular weight of less than 150,
The content of the organic polyisocyanate (a1) in the resin of the composition obtained from (A) and (B) is 1.06-1.17 mmol / g, and the crosslinking agent concentration is 0.11-0. A polyurethane elastomer-forming composition for casting, having a high resilience and a low strain of 16 mmol / g.
II. Formation of polyurethane elastomer for casting according to I above, wherein (b2) is a polyester polyol having a nominal average functional group number of 3 consisting of trimethylolpropane, 3-methyl-1,5-pentanediol, and adipic acid Sex composition.
III. The polyurethane elastomer-forming composition for casting according to I above, wherein (b2) is a polyester polyol having a nominal average functional group number of 3 consisting of trimethylolpropane, 1,4-butanediol, and adipic acid.
IV. (B2) is a polyester polyol having a nominal average functional group number of 3 consisting of trimethylolpropane, 3-methyl-1,5-pentanediol and adipic acid, and trimethylolpropane, 1,4-butanediol and adipine A polyurethane elastomer-forming composition for casting according to the above I comprising a polyester polyol having a nominal average functional group number of 3 consisting of an acid.
V. A roll member comprising the polyurethane elastomer composition for casting according to any one of I to IV.
VI. A glass run for automobiles comprising the polyurethane elastomer composition for casting according to any one of I to IV above.
VII. The manufacturing method of the polyurethane elastomer formation composition for casting in any one of said I to IV.

The cast polyurethane elastomer composition obtained by the present invention has a rebound resilience of 40% or more, a permanent elongation of 1.3% or less, and a compression set of 2.0% or less. The polyurethane elastomer composition for a mold can be suitably used as a component for industrial equipment such as a glass run for automobiles and a small roll represented by a paper feed roll.

  As means for solving the problems of the present invention, the above-described embodiments of the present invention will be described in detail below.

  The isocyanate group-terminated prepolymer (A) in the present invention is charged with an organic polyisocyanate (a1) and a hydroxyl group-containing compound (a2) at a ratio of isocyanate group / hydroxyl group (molar ratio) of 1.6 to 20, By reacting this system at a temperature of 50 to 100 ° C. for 1 to 5 hours, a specific isocyanate group-terminated urethane prepolymer (A) can be obtained.

As the organic polyisocyanate (a1) in the present invention, those conventionally used can be used. Examples of such organic polyisocyanates include aromatic polyisocyanates having 6 to 20 carbon atoms [1,3- and / or 1,4-phenylene diisocyanate, 2,4- and / or 2,6-tolylene diisocyanate ( TDI), 2,4′- and / or 4,4′-diphenylmethane diisocyanate (MDI) and the like]; aliphatic polyisocyanate having 2 to 18 carbon atoms [ethylene diisocyanate, hexamethylene diisocyanate and the like]; 4 to 15 carbon atoms Alicyclic polyisocyanates [xylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI), etc.]; araliphatic polyisocyanates having 8 to 15 carbon atoms; and these two The above mixture is mentioned. Among these, aromatic polyisocyanates having 6 to 20 carbon atoms are preferable, and 2,4- and / or 2,6-tolylene diisocyanate (TDI), 2,4′- and / or 4,4 ′ are more preferable. -Diphenylmethane diisocyanate, the most suitable being 4,4'-diphenylmethane diisocyanate.

Examples of the hydroxyl group-containing compound (a2) in the present invention include one or a mixture of two or more of polyether polyol, polyester polyol, polycarbonate diol, etc. Among them, polyester polyol is preferable. These molecular weights have an average molecular weight of 50 to 5,000, among which a number average molecular weight of 300 to 4,000 is preferable, and a number average molecular weight of 500 to 3,000 is more preferable.

Examples of the polyether glycol include poly (ethylene ether) glycol, poly (propylene ether) glycol, and poly (tetramethylene ether) glycol (hereinafter abbreviated as “PTMG”). These are ethylene glycol (hereinafter abbreviated as “EG”), 1,3-butanediol (hereinafter abbreviated as “1,3-BD”), 1,4-butanediol (hereinafter abbreviated as “1,4-BD”). ), Diethylene glycol, dipropylene glycol, 1,2-propylene glycol (hereinafter abbreviated as “1,2-PG”), 1,3-propylene glycol (hereinafter abbreviated as “1,3-PG”), etc. Is a polyether polyol from one or more of polyethers and the like produced by ring-opening polymerization of cyclic ethers such as ethylene oxide, propylene oxide, trimethylene oxide and tetrahydrofuran. Among these, poly (tetramethylene ether) glycol is preferable.

Examples of the polyester polyol include ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, One or more of neopentyl glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, decamethylene glycol, bisphenol A, hydrogenated bisphenol A, malonic acid, malein Polyester polyols from one or more of acids, succinic acid, adipic acid, glutaric acid, pimelic acid, sebacic acid, oxalic acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid and the like. Among these, a polyester polyol of adipic acid and 1,4-butanediol is preferable.

Examples of the polycarbonate diol include those obtained by polycondensation from the above-mentioned short chain diol and low molecular carbonates such as diphenyl carbonate, diethyl carbonate, and ethylene carbonate. Mixtures of these polycarbonates can also be used.

If necessary, a catalyst for promoting the NCO / OH reaction can be added during the preparation of the prepolymer. Suitable catalysts include known amine compounds or organometallic compounds or quaternary ammonium salts.
As examples, the following compounds can be used as catalysts: triethylamine, tributylamine, dimethylbenzylamine, dicyclohexylmethylamine, dimethylcyclohexylamine, N, N, N ′, N′-tetramethyldiaminodiethyl ether, bis ( Dimethylaminopropyl) urea, N-methyl- and N-ethylmorpholine, N, N′-dimorpholinodiethyl ether (DMDEE), N-cyclohexylmorpholine, N, N, N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetramethylbutanediamine, N, N, N ′, N′-tetramethylhexane-1,6-diamine, pentamethyldiethylenetriamine, dimethylpiperazine, N-dimethyl-aminoethyl-piperidine, 1 , 2-dimethylimidazole, N-hydroxypropylimidazole, 1-azashi Black [22.0] octane, 1,
4-diazacyclo [2.2.2] octane (Dabco) and alkanolamine compounds (
For example, triethanolamine, triisopropanolamine, N-methyl- and N-ethyldiethanolamine), dimethylaminoethanol, 2- (N, N-dimethylaminoethoxy) ethanol, N, N ′, N-tris (dialkylaminoalkyl) Dialkylaminoalkyl) hexahydrotriazine (eg N, N ′, N-tris (dimethylaminopropyl)-
s-hexahydrotriazine), iron chloride (II), zinc chloride, lead octoate and tin salts (eg, tin dioctoate, tin diethylhexoate, dibutyltin dilaurate and / or dibutyldilauryltin mercaptide), 2 , 3-dimethyl-3,4,5,6-tetrahydropyrimidine, tetraalkylammonium hydroxide (eg, tetramethylammonium hydroxide), alkali metal hydroxide (eg, sodium hydroxide), alkali metal alkoxide (eg, Sodium methoxide and potassium isopropoxide), and / or alkali metal salts of long chain fatty acids having 10 to 20 carbon atoms and optionally pendant OH groups, benzyltrimethylammonium chloride, phenyltributylammonium Examples thereof include one kind or a mixture of two or more kinds of quaternary ammonium salts such as muchloride and benzyltrimethylammonium chloride.

Further, if necessary, existing antioxidants, defoaming agents, ultraviolet absorbers, reaction modifiers and the like can be added during the production of the prepolymer.

The NCO content of the isocyanate group-terminated prepolymer is preferably 5.0-25.0% by mass, more preferably 8.0-20.0% by mass, and most preferably 10.0-18. 0% by mass.
The isocyanate group-terminated prepolymer having an NCO content of less than 5.0% by mass has a high viscosity and is inferior in fluidity, and it becomes difficult to perform a casting operation of a composition containing this as a main component. On the other hand, an isocyanate group-terminated prepolymer having an NCO content exceeding 25.0% by mass is excessively reactive with an active hydrogen compound (curing agent), and a composition comprising this as a main component (mixture with a curing agent). In this case, the fluidity is drastically lowered and the casting operation becomes difficult. In addition, there is a problem that stability is significantly lowered during storage and use, and molding defects are likely to occur.

The isocyanate group-terminated prepolymer obtained by the present invention has a dynamic viscosity at 75 ° C. of preferably 50 to 3,000 mm 2 / s, more preferably 100 to 2,500 mm 2 / s.
The isocyanate group-terminated prepolymer having a viscosity of less than 50 mm <2> / s has a problem that the viscosity difference from the curing agent is large and the liquid is not easily mixed well during mixing. On the other hand, an isocyanate group-terminated prepolymer having a viscosity exceeding 3,000 mm2 / s has a high initial viscosity, and its fluidity is drastically lowered due to the reaction with the active hydrogen compound (curing agent), making the casting operation difficult.

The curing agent (B) in the present invention comprises a polyester polyol (b1) having a molecular weight of 500 to 2,500 and a nominal average functional group number of 2, a dibasic acid (b21), a triol (b22) having a molecular weight of 500 or less, and a molecular weight of 300. The polyester polyol (b2) having a nominal average functional group number of 3 having a molecular weight of 500 to 2,500 comprising the following glycol (b23) and a glycol (b3) having a molecular weight of less than 150.
Here, the “nominal average functional group number” is the number of functional groups described in the manufacturer's production guide or the like. Or it is the number of functional groups calculated | required by calculating from preparation amount.

  As the polyester polyol (b1) of the present invention, among the polyester polyols used in the above (a2), a polyester polyol having a molecular weight of 500 to 2,500 and a nominal average functional group number of 2 can be suitably used. It is preferable to use the same polyester polyol as (a2) used in the isocyanate prepolymer.

The polyester polyol (b2) having a nominal average functional group number of 3 of the present invention comprises a dibasic acid (b21), a triol (b22) having a molecular weight of 500 or less, and a glycol (b23) having a molecular weight of 300 or less. Of these, as (b21), malonic acid, maleic acid, succinic acid, adipic acid, glutaric acid, pimelic acid, sebacic acid, oxalic acid, phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, etc. 1 type or the mixture of 2 or more types of the dibasic acids currently used for is mentioned. As (b22), generally used triols having a molecular weight of 500 or less such as trimethylolpropane and glycerin can be used. (B23) includes ethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 2-methyl-1, Such as 3-propanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, decamethylene glycol, bisphenol A, hydrogenated bisphenol A, etc. One kind or a mixture of two or more kinds may be mentioned. The polyester polyol (b2) obtained by dehydration condensation of (b21), (b22), and (b23) preferably has a number average molecular weight of 500 to 2,500, and more preferably 1,000 to 2,000. When the number average molecular weight is less than 500, there is a problem that the impact resilience of the resulting elastomer composition for casting becomes low and the intended effect cannot be achieved. Poor solubility causes the appearance of the molded product to become cloudy and causes problems such as non-uniform physical properties.
Preferred as (b2) is a polyester polyol composed of trimethylolpropane and 3-methyl-1,5-pentanediol and / or 1,4-butanediol and adipic acid, and most preferred is trimethylolpropane and 3 -Polyester polyol composed of methyl-1,5-pentanediol and adipic acid.

  Examples of the diol (b3) having a molecular weight of less than 150 of the present invention include ethylene glycol, propylene glycol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, and 1,5-pentanediol. , 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and the like. These can be used alone or in combination of two or more. In the present invention, 1,4-butanediol is particularly preferable among these from the viewpoint that suitable hardness and mechanical properties can be obtained in the molded product desired in the present invention.

In the resin composition obtained by the present invention, the content of the organic polyisocyanate (a1) with respect to the whole resin must be in the range of 1.06 to 1.17 mmol / g, preferably 1.07 to 1. The range is 15 mmol / g, more preferably 1.10 to 1.13 mmol / g. When the content of the organic polyisocyanate (a1) is less than 1.06 mmol / g, permanent elongation and compression set are deteriorated, and other physical properties are also lowered. When the content of the organic polyisocyanate (a1) exceeds 1.17 mmol / g, the impact resilience, permanent elongation, and compression set are all deteriorated, resulting in problems such as the resin becoming brittle.
-Content of the organic polyisocyanate (a1) in resin is represented by following Formula.

[{A1 / (a1 + a2) × A} / (a1Mn)] / (A + B) × 1000

a1: Compounding amount (g) of the organic polyisocyanate (a1) in the isocyanate prepolymer (A)
a2: Compounding amount of the hydroxyl group-containing compound (a2) in the isocyanate prepolymer (A)
(G)
A: Blending amount (g) of isocyanate prepolymer (A)
B: Blending amount (g) of curing agent (B)
a1Mn: Molecular weight of organic polyisocyanate (a1)

In addition to this, in the resin composition obtained by the present invention, the content of the trifunctional polyol component with respect to the entire resin (in the present specification, described as the crosslinking agent concentration) is 0.11 to 0.16 mmol. / G, preferably 0.12 to 0.15 mmol / g, more preferably 0.13 to 0.14 mmol / g. When the concentration of the crosslinking agent is less than 0.11 mmol / g, permanent elongation and compression set are deteriorated, and when it exceeds 0.16 mmol / g, rebound resilience, permanent elongation and compression set are both deteriorated.
-The concentration of the crosslinking agent in the resin is expressed by the following formula.

{B2 / (b1 + b2 + b3) × B / (b2Mn)} / (A + B) × 1000

b1: Compounding amount (g) of the bifunctional polyester (b1) in the curing agent (B)
b2: Blending amount (g) of trifunctional polyester (b2) in the curing agent (B)
b3: Blending amount (g) of glycol (b3) in curing agent (B)
A: Blending amount (g) of isocyanate prepolymer (A)
B: Blending amount (g) of curing agent (B)
b2Mn: Molecular weight of trifunctional polyester (b2)

  The cast polyurethane elastomer molded product in the present invention is obtained by thermally curing a forming composition in the present invention, that is, a composition comprising the isocyanate group-terminated prepolymer (A) and the curing agent (B) in a mold. be able to.

  When the isocyanate group-terminated prepolymer (A) and the curing agent (B) are mixed, the aforementioned catalyst, existing antioxidant, defoaming agent, ultraviolet absorber, reaction modifier, etc. can be added in advance. It is preferable to add to the curing agent (B).

  The method for producing a two-liquid cast polyurethane elastomer molded product according to the present invention comprises the step of obtaining the forming composition of the present invention by mixing the isocyanate group-terminated prepolymer (A) and the curing agent (B) according to the present invention. A step of pouring the obtained composition into a mold and a step of curing the composition by heating in the mold.

  In the composition of the present invention, the mixing ratio (blending ratio R) of the isocyanate group-terminated prepolymer (A) and the curing agent (B) is an isocyanate group contained in the isocyanate component constituting the main agent (A); The molar ratio (isocyanate group / active hydrogen group) with the active hydrogen group of the polyol component constituting B) is preferably 0.8 to 1.6, more preferably 0.9 to The ratio is 1.4, and particularly preferably the ratio is 1.0 to 1.2.

The method for producing the polyurethane elastomer composition for casting of the present invention is not particularly limited. For example, a prepolymer method in which a urethane prepolymer composed of an organic polyisocyanate and a high molecular polyol and a chain extender such as a low molecular glycol are reacted; A semi-one shot method in which an isocyanate group-terminated prepolymer (A) in which a polymer polyol is incorporated on both the prepolymer side and the curing agent as in the present invention and a curing agent (B) are mixed and reacted; And the one-shot method of reacting.
Among these, the semi-one shot method is preferable in consideration of workability and heat generation during the reaction.

As a specific manufacturing procedure of the urethane elastomer molded article for casting of the present invention, the above-mentioned raw materials and molds are used, for example, as follows.
1. The isocyanate group-terminated prepolymer (A) and the curing agent (B) are uniformly mixed and defoamed. 2. The liquid is poured into a preheated mold (casting) and heated to cause a curing reaction. The temperature at this time is about 60-200 degreeC.
3. Leave it in a heated state for a while, and after the poured liquid has hardened, remove the cured product from the mold (demolding).
4). If necessary, the molded product after demolding may be post-heated.

Examples of the present invention will be described below, but the present invention should not be construed as being limited thereto. In the following description, “parts” and “%” mean “parts by mass” and “% by mass”, respectively.

<Prepolymer synthesis example>
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen seal tube, and a cooling tube was purged with nitrogen. To this, 544 parts of pure MDI (Millionate-MT, manufactured by Nippon Polyurethane Industry Co., Ltd.) and when the liquid temperature reached 50 ° C., polybutylene adipate having a number average molecular weight: Mn = 2,000: BA-2000 ( 456 parts of Nippon Polyurethane Industry Co., Ltd.) was added and reacted by stirring and mixing at 75 ° C. for 3 hours under a nitrogen atmosphere, and NCO content: 16.4%, viscosity: 200 mm 2 / s (75 ° C. ) Was obtained. Hereinafter, this is referred to as an isocyanate group-terminated prepolymer “P-1”.

<Preparation Example 1>
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen seal tube, and a cooling tube was purged with nitrogen. To this, 345 parts of polybutylene adipate BA-1000 having a number average molecular weight: Mn = 1,000 and 558 parts of trifunctional polyester polyol: F-2010 having a number average molecular weight: Mn = 2,000, 1,4, A curing agent was obtained by adding 97 parts of -BD and 0.2 part of TEDA and stirring and mixing at 70 ° C. for 3 hours in a nitrogen atmosphere. Hereinafter, this is referred to as a curing agent “B-1”.

<Preparation Example 2>
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen seal tube, and a cooling tube was purged with nitrogen. To this, 257 parts of BA-1000 and 376 parts of polybutylene adipate BA-2000 having a number average molecular weight: Mn = 2,000 and trifunctional polyester polyol: F-1010 having a number average molecular weight: Mn = 1,000 A curing agent was obtained by adding 279 parts, 88 parts of 1,4-BD, and 0.2 part of TEDA, and stirring and mixing at 70 ° C. for 3 hours in a nitrogen atmosphere. Hereinafter, this is referred to as a curing agent “B-2”.

<Preparation Example 3>
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen seal tube, and a cooling tube was purged with nitrogen. To this, 255 parts of BA-1000, 377 parts of BA-2000, 280 parts of trifunctional polyester polyol A having a number average molecular weight: Mn = 1,000, 88 parts of 1,4-BD, TEDA 0.2 part was added and the hardening | curing agent was obtained by stirring and mixing over 3 hours at 70 degreeC by nitrogen atmosphere. Hereinafter, this is referred to as a curing agent “B-3”.

<Preparation Example 4>
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen seal tube, and a cooling tube was purged with nitrogen. To this, 345 parts of BA-1000, 558 parts of trifunctional polylactone polyol PCL-320 having a number average molecular weight: Mn = 2,000, 97 parts of 1,4-BD, and 0.2 part of TEDA The resulting mixture was stirred and mixed at 70 ° C. for 3 hours under a nitrogen atmosphere to obtain a curing agent. Hereinafter, this is referred to as a curing agent “B-4”.

<Preparation Example 5>
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen seal tube, and a cooling tube was purged with nitrogen. To this, 35 parts of BA-1000, functional polyester polyol of number average molecular weight: Mn = 3,000: 840 parts of F-3010, 125 parts of 1,4-BD, and 0.2 part of TEDA are added. Then, a curing agent was obtained by stirring and mixing at 70 ° C. for 3 hours in a nitrogen atmosphere. Hereinafter, this is referred to as a curing agent “B-5”.

<Preparation Example 6>
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen seal tube, and a cooling tube was purged with nitrogen. 207 parts of BA-1000, 693 parts of F-2010, 100 parts of 1,4-BD and 0.2 part of TEDA were added thereto, and the mixture was stirred and mixed at 70 ° C. for 3 hours in a nitrogen atmosphere. To obtain a curing agent. Hereinafter, this is referred to as a curing agent “B-6”.

<Preparation Example 7>
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen seal tube, and a cooling tube was purged with nitrogen. To this, 435 parts of BA-1000, 70 parts of BA-2000, 408 parts of F-2010, 96 parts of 1,4-BD and 0.2 part of TEDA were added, and 70 parts in a nitrogen atmosphere. A curing agent was obtained by stirring and mixing at 3 ° C. for 3 hours. Hereinafter, this is referred to as a curing agent “B-7”.

<Preparation Example 8>
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen seal tube, and a cooling tube was purged with nitrogen. To this, 275 parts of BA-1000, 600 parts of F-2010, 125 parts of 1,4-BD and 0.2 part of TEDA were added and stirred and mixed at 70 ° C. for 3 hours in a nitrogen atmosphere. To obtain a curing agent. Hereinafter, this is referred to as a curing agent “B-8”.

<Preparation Example 9>
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen seal tube, and a cooling tube was purged with nitrogen. To this, 377 parts of BA-2000, 527 parts of F-2010, 96 parts of 1,4-BD, and 0.2 part of TEDA were added, and stirred and mixed at 70 ° C. for 3 hours in a nitrogen atmosphere. To obtain a curing agent. Hereinafter, this is referred to as a curing agent “B-9”.

<Preparation Example 10>
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen seal tube, and a cooling tube was purged with nitrogen. To this, add 874 parts of BA-2000, 88 parts of 1,4-BD, 38 parts of TMP and 0.2 part of TEDA, and stir and mix in a nitrogen atmosphere at 70 ° C. for 3 hours. To obtain a curing agent. Hereinafter, this is referred to as a curing agent “B-10”.

<Preparation Example 11>
The inside of a 2 L four-necked flask equipped with a thermometer, a stirrer, a nitrogen seal tube, and a cooling tube was purged with nitrogen. Add 874 parts of BA-2000, 101 parts of 1,4-BD, 25 parts of TMP and 0.2 part of TEDA to this, and stir and mix in a nitrogen atmosphere at 70 ° C. for 3 hours. To obtain a curing agent. Hereinafter, this is referred to as a curing agent “B-11”.

  Curing agents B1 to B11 obtained in Adjustment Examples 1 to 11 are shown in Tables 1 and 2.

<Description of Abbreviations for Raw Materials Used in the Present Invention>
Pure MDI: Diphenylmethane diisocyanate containing 99% or more of 4,4′-diphenylmethane diisocyanate isomer (Millionate MT, manufactured by Nippon Polyurethane Industry Co., Ltd.)
BA-1000: polybutylene adipate having a number average molecular weight Mn of 1,000 (manufactured by Nippon Polyurethane Industry Co., Ltd.)
BA-2000: polybutylene adipate having a number average molecular weight Mn of 2,000 (manufactured by Nippon Polyurethane Industry Co., Ltd.)
Polyol A: polyester obtained by reacting 337 parts of 1,4-butanediol, 116 parts of trimethylolpropane and 547 parts of adipic acid, having a number average molecular weight of 1,000 and a nominal average functional group number of 3. Polyol F-1010: Polyester polyol composed of 3-methyl-1,5-pentanediol, trimethylolpropane and adipic acid, having a nominal average functional group number of 3 and a number average molecular weight of 1,000 (Kuraray polyol F-1010 F-2010: Polyester polyol composed of 3-methyl-1,5-pentanediol, trimethylolpropane and adipic acid having a nominal average functional group number of 3 and a number average molecular weight of 2,000 Kuraray polyol F-2010, manufactured by Kuraray Co., Ltd.)
F-3010: Polyester polyol composed of 3-methyl-1,5-pentanediol, trimethylolpropane and adipic acid having a nominal average functional group number of 3 and a number average molecular weight of 3,000 (Kuraray polyol F-3010, PCL-320: polycaprolactone polyol having a number average molecular weight of 2,000 and a nominal average functional group number of 3 (Placcel PCL-320, manufactured by Daicel Chemical Industries, Ltd.)
TMP: Trimethylolpropane (Mitsubishi Gas Chemical Co., Ltd.)
1,4-BD: 1,4-butanediol (manufactured by Tosoh Corporation)
TEDA: Triethylenediamine (manufactured by Tosoh Corporation)

<Examples 1-3, Comparative Examples 1-8>
According to the composition described in Table 1, the isocyanate prepolymer P-1 and the curing agents B1 to B11 are heated to 80 ° C., mixed and stirred with an agitator for 30 seconds, then injected into a centrifugal molder, and reacted at 130 ° C. for 60 minutes. It was cured to obtain a sheet-like (thickness: 2 mm) polyurethane elastomer composition. The obtained sheet-like polyurethane elastomer composition was cured for one week at room temperature (25 ° C.), and then each physical property was measured. The results are listed in Table 3.
“Isocyanate content” in Table 3 is an abbreviation of “content of organic polyisocyanate (a1)” in the specification.

  The physical properties described in Table 1 were measured by the methods described below.

The number average molecular weight of the hydroxyl group-containing compound described in the present invention was calculated by the value described in the manufacturer's results table or the terminal hydroxyl group quantification method.

(Measurement method of hardness)
Using durometer type A defined in JIS-K6253, measurement was performed according to JIS-K7312.

(Measuring method of mechanical properties)
About each of the obtained urethane elastomer molding, based on JIS-K7312, tensile strength, breaking elongation, tear strength, and impact resilience were measured.
Here, the measurement of hardness, tensile strength, elongation at break, and tear strength was performed in a constant temperature and humidity environment at a temperature of 23 ° C. and a relative humidity of 50%.

(Permanent elongation measurement method)
Using a No. 1 dumbbell-shaped test piece shown in JIS-K7312, a 40 mm mark was attached to the center, stretched 100% for 10 minutes, opened, and allowed to stand for 10 minutes, and the distance between the marks was measured. . From this result, the residual strain ratio with respect to the first distance between the marked lines was calculated to obtain permanent elongation.

(Compression set)
Measurement was performed in accordance with JIS7312. Compressibility: 25%, left at 70 ° C. for 22 hours, then allowed to cool for 30 minutes in a constant temperature and humidity environment at a temperature of 23 ° C. and a relative humidity of 50%.

(Measurement method of storage modulus)
[Tan δ peak temperature]
First, the cured body constituting the elastomer composition was molded and measured to 50 mm × 5 mm × 2 mm to prepare a sample. Next, this sample was set so that the gap between the chucks of the tension jig was 38 mm, and an excitation amplitude of −25 μm to +25 μm, a minimum weight amplitude of 0 gf, a preload load of 50.0 gf, and a frequency of 11 Hz were applied, and − Tan δ (loss tangent) in the range of 50 ° C. to 150 ° C. was measured every 2 ° C. at a heating rate of 2 ° C./min. (Equipment: Orientec's DDV-25FP)

(Sheet appearance)
When the sheet was confirmed by visual inspection, a highly transparent sheet was marked with ◯, and a cloudy sheet was marked with x. If it becomes cloudy, the physical properties of the resulting sheet will be non-uniform.

Claims (7)

A polyurethane resin-forming composition comprising an isocyanate prepolymer (A) and a curing agent (B),
(A) is an isocyanate group-terminated prepolymer comprising an organic polyisocyanate (a1) and a hydroxyl group-containing compound (a2),
(B) is a polyester polyol (b1) having a nominal average functional group number of 2 having a molecular weight of 500 to 2,500, a dibasic acid (b21), a triol (b22) having a molecular weight of 500 or less, and a glycol (b23 having a molecular weight of 300 or less) A polyester polyol (b2) having a molecular weight of 500 to 2,500 and a nominal average functional group number of 3 and a glycol (b3) having a molecular weight of less than 150,
The content of the organic polyisocyanate (a1) in the resin of the composition obtained from (A) and (B) is 1.06-1.17 mmol / g, and the crosslinking agent concentration is 0.11-0. A polyurethane elastomer-forming composition for casting, having a high resilience and a low strain of 16 mmol / g. The polyurethane elastomer for casting according to claim 1, wherein (b2) is a polyester polyol having a nominal average functional group number of 3 consisting of trimethylolpropane, 3-methyl-1,5-pentanediol, and adipic acid. Sex composition. The polyurethane elastomer-forming composition for casting according to claim 1, wherein (b2) is a polyester polyol having a nominal average functional group number of 3 consisting of trimethylolpropane, 1,4-butanediol, and adipic acid. . (B2) is a polyester polyol having a nominal average functional group number of 3 consisting of trimethylolpropane, 3-methyl-1,5-pentanediol and adipic acid, and trimethylolpropane, 1,4-butanediol and adipine The polyurethane elastomer-forming composition for casting according to claim 1, comprising a polyester polyol having a nominal average functional group number of 3 consisting of an acid. A roll member comprising the polyurethane elastomer composition for casting according to any one of claims 1 to 4. An automotive glass run comprising the polyurethane elastomer composition for casting according to any one of claims 1 to 4. A method for producing a polyurethane elastomer-forming composition for casting according to any one of claims 1 to 4.