JP2008222750A - Thermosetting urethane elastomer forming composition and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that in mechanical component parts of industrial apparatuses such as an automobile glass run, a small-sized roll represented by a paper feed roll, etc., component parts having an excellent impact resilience, permanent set and permanent compression set are demanded, however, a conventional casting polyurethane elastomer composition does not satisfy all of impact resilience, permanent set and permanent compression set. <P>SOLUTION: The casting polyurethane elastomer forming composition comprises an isocyanate group terminal prepolymer, a hydroxy group-containing polymer polyol as a curing agent, a polyester polyol having a molecular weight of 500-2,500 and a nominal average functional group number of 3, a difunctional glycol having a molecular weight of <150 and a triol having a molecular weight of <500. The casting polyurethane elastomer composition has an excellent impact resilience, permanent set and permanent compression set. As a result, the casting polyurethane elastomer forming composition is used for the automobile glass run, a roll member, etc. <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, a polyester polyurethane elastomer composition having a JIS-A hardness of 60 to 80 degrees using 1,4-butanediol (1,4-BD) / trimethylolpropane (TMP) as a chain extender conventionally used. The product has a rebound resilience of 30% or less and cannot satisfy the required properties (Comparative Example 9 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 10 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 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 for casting from a mixture of a polyester polyol having a nominal average functional group number of 3 to 500 to 2500, a glycol having a molecular weight of less than 150, and a triol having a molecular weight of less than 500, the impact resilience, permanent elongation, and compression are obtained. A polyurethane elastomer composition for casting having good permanent set can be obtained. The headline was led to the present invention.

That is, the present invention is the following I to IX.
I. A polyurethane resin-forming composition comprising an isocyanate prepolymer (A) and a curing agent (B), wherein (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 molecular weight of 300 or less. A mixture of a polyester polyol (b2) having a nominal average functional group number of 3 having a molecular weight of 500 to 2,500, a glycol (b3) having a molecular weight of less than 150, and a triol (b4) having a molecular weight of less than 500. The content of the organic polyisocyanate (a1) in the resin obtained from (A) and (B) Polyurethane elastomer-forming composition for casting, characterized in that it is 0.8 to 1.2 mmol / g and the crosslinking agent concentration is 0.11 to 0.16 mmol / g, and has high resilience and low strain. .
II. The polyurethane elastomer-forming composition for casting according to I, 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 object.
III. The polyurethane elastomer-forming composition for casting according to I, 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 The polyurethane elastomer-forming composition for casting according to I, comprising a polyester polyol having a nominal average functional group number of 3 consisting of an acid.
V. The molar ratio of (b2) in the curing agent (B) to the triol (b4) having a molecular weight of less than 500 is (b2) / (b4) = 60/40 to 99/1, A polyurethane elastomer-forming composition for casting.
VI. The polyurethane elastomer-forming composition for casting according to any one of I to V, wherein the triol (b4) having a molecular weight of less than 500 is trimethylolpropane.
VII. A roll member comprising the polyurethane elastomer for casting according to any one of I to VI.
VIII. An automotive glass run comprising the polyurethane elastomer for casting according to any one of I to VI.
IX. A method for producing a polyurethane elastomer for casting according to any one of I to VI.

  The cast polyurethane elastomer composition obtained by the present invention has a rebound resilience of 35% or more, a permanent elongation of 1.0% or less, and a compression set of 1.5% or less. The polyurethane elastomer 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 An alicyclic polyisocyanate [xylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI), etc.]; an aromatic aliphatic polyisocyanate having 8 to 15 carbon atoms; 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 300 to 5,000. Among them, a number average molecular weight of 400 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 Chlo [22.0] octane, 1,4-diazacyclo [2.2.2] octane (Dabco) and alkanolamine compounds (eg, triethanolamine, triisopropanolamine, N-methyl- and N-ethyldiethanolamine) ), Dimethylaminoethanol, 2- (N, N-dimethylaminoethoxy) ethanol, N, N ′, N-tris (dialkylaminoalkyldialkylaminoalkyl) hexahydrotriazine (eg, N, N ′, N-tris ( Dimethylaminopropyl) -s-hexahydrotriazine), iron (II) chloride, zinc chloride, lead octoate, and tin salts (eg, tin dioctoate, tin diethylhexoate, dibutyltin dilaurate and / or dibutyldilauryl tin) Lucaptide) 2,3-dimethyl-3,4,5,6-tetrahydropyrim , Tetraalkylammonium hydroxide (eg, tetramethylammonium hydroxide), alkali metal hydroxide (eg, sodium hydroxide), alkali metal alkoxide (eg, sodium methoxide and potassium isopropoxide), and / or 10 1 type of quaternary ammonium salts such as alkali metal salts of -20 carbon atoms and, if necessary, long chain fatty acids having pendant OH groups, benzyltrimethylammonium chloride, phenyltributylammonium chloride, benzyltrimethylammonium chloride Or the mixture of 2 or more types is mentioned.

  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. 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 an 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. Consists of a polyester polyol (b2) having a nominal average functional group number of 3 having a molecular weight of 500 to 2,500 consisting of the following glycol (b23), a glycol (b3) having a molecular weight of less than 150, and a triol having a molecular weight of less than 500 (b4). Is done.
Here, the “nominal average functional group number” refers to the functional group number described in the manufacturer's production guide or the like.

  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 group-terminated 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), trimethylolpropane, glycerin, 1,1 ′, 1 ″ -nitrilotri-2propanol, 2,2 ′, 2 ″ -nitrilotriethanol, hydroxypropyldiethanolamine and the like are generally used. Triols having a molecular weight of 500 or less 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.

  Examples of the triol (b4) having a molecular weight of less than 500 of the present invention include trimethylolpropane, glycerin, 1,1 ′, 1 ″ -nitrilotri-2propanol, 2,2 ′, 2 ″ -nitrilotriethanol, hydroxypropyldiethanolamine and the like. The generally used triol having a molecular weight of 500 or less can be used. Of these, trimethylolpropane is preferred.

In the resin composition obtained by the present invention, the content of the organic polyisocyanate (a1) relative to the entire resin must be in the range of 0.8 to 1.2 mmol / g, preferably 0.9 to 1. It is 2 mmol / g, More preferably, it is the range of 1.0-1.1 mmol / g. When the content of the organic polyisocyanate (a1) is less than 0.8 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 1.2 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)
a1Mn: Molecular weight of organic polyisocyanate (a1) A: Blending amount of isocyanate group-terminated prepolymer (A) (g)
B: Blending amount (g) of curing agent (B)


In addition, the resin composition obtained by the present invention must have a trifunctional polyol component content (crosslinker concentration) in the range of 0.11 to 0.16 mmol / g based on the entire resin. Preferably, it is 0.12-0.15 mmol / g, More preferably, it is 0.13-0.14 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 + b4) × B / (b2Mn)} + {b4 / (b1 + b2 + b3 + b4) × B / b4Mn}] / (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)
b4: Blending amount (g) of triol (b4) having a molecular weight of less than 500 in the curing agent (B)
b2Mn: number average molecular weight of trifunctional polyester polyol (b2) b4Mn: molecular weight of triol (b4) having a molecular weight of less than 500 A: blending amount (g) of isocyanate group-terminated prepolymer (A)
B: Blending amount (g) of curing agent (B)

  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, 545 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 ( 453 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, 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, 509 parts of polybutylene adipate BA-2000 having a number average molecular weight: Mn = 2,000, 403 parts of trifunctional polyester polyol: F-2010 having a number average molecular weight: Mn = 2,000, 1,4 -81 parts of BD, 7 parts of TMP and 0.2 part of TEDA were added, and 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-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, 592 parts of BA-2000, 311 parts of F-2010, 83 parts of 1,4-BD, 14 parts of TMP and 0.2 part of TEDA were added, and 70 ° C. in a nitrogen atmosphere. The curing agent was obtained by stirring and mixing for 3 hours. 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, 691 parts of BA-2000, trifunctional polyester polyol with number average molecular weight: Mn = 1,000: 218 parts of F-1010, 84 parts of 1,4-BD, 7 parts of TMP, 0.2 part of TEDA was added, and a curing agent was obtained by stirring and mixing at 70 ° C. for 3 hours under a 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, 509 parts of BA-2000, 403 parts of trifunctional polylactone polyol PCL-320 having a number average molecular weight: Mn = 2,000, 81 parts of 1,4-BD, 7 parts of TMP, 0.2 part of TEDA was added, and a curing agent was obtained by stirring and mixing at 70 ° C. for 3 hours under a nitrogen atmosphere. 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, 333 parts of BA-2000, functional polyester polyol with number average molecular weight: Mn = 3,000: 583 parts of F-3010, 77 parts of 1,4-BD, 7 parts of TMP, 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-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. To this, 413 parts of BA-2000, 501 parts of F-2010, 77 parts of 1,4-BD, 9 parts of TMP and 0.2 part of TEDA were added, and 70 ° C. in a nitrogen atmosphere. The curing agent was obtained by stirring and mixing for 3 hours. 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, 614 parts of BA-2000, 295 parts of F-2010, 86 parts of 1,4-BD, 5 parts of TMP and 0.2 part of TEDA were added, and 70 ° C. in a nitrogen atmosphere. The curing agent was obtained by stirring and mixing 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, 653 parts of BA-2000, 256 parts of F-2010, 74 parts of 1,4-BD, 17 parts of TMP and 0.2 part of TEDA were added, and 70 ° C. in a nitrogen atmosphere. The curing agent was obtained by stirring and mixing for 3 hours. 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, 410 parts of BA-2000, 505 parts of F-2010, 85 parts of 1,4-BD and 0.2 parts of TEDA were added, and 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-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, 352 parts of polybutylene adipate BA-1000 with a number average molecular weight: Mn = 1,000, 503 parts of F-2010, 136 parts of 1,4-BD, 9 parts of TMP, 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-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. To this, 640 parts of BA-2000, 328 parts of F-2010, 26 parts of 1,4-BD, 6 parts of TMP and 0.2 part of TEDA were added, and 70 ° C. in a nitrogen atmosphere. The curing agent was obtained by stirring and mixing for 3 hours. Hereinafter, this is referred to as a curing agent “B-11”.

<Preparation Example 12>
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. By adding 874 parts of BA-2000, 88 parts of 1,4-BD, 38 parts of TMP, and 0.2 g of TEDA, and stirring and mixing at 70 ° C. for 3 hours in a nitrogen atmosphere. A curing agent was obtained. Hereinafter, this is referred to as a curing agent “B-12”.

<Preparation Example 13>
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. By adding 874 parts of BA-2000, 101 parts of 1,4-BD, 25 parts of TMP, and 0.2 g of TEDA, and stirring and mixing at 70 ° C. for 3 hours under a nitrogen atmosphere. A curing agent was obtained. Hereinafter, this is referred to as a curing agent “B-13”.

Tables 1 and 2 show curing agents B1 to B13 obtained in Adjustment Examples 1 to 13, respectively.

<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 nominal average functional group number of 2 and a number average molecular weight Mn of 1,000 (manufactured by Nippon Polyurethane Industry Co., Ltd.)
BA-2000: Polybutylene adipate having a nominal average functional group number of 2 and a number average molecular weight Mn of 2,000 (manufactured by Nippon Polyurethane Industry Co., Ltd.)
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 (Kuraray) consisting 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 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 1-10>
According to the composition described in Table 1, the isocyanate prepolymer P-1 and the curing agents B1 to B13 were 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 shown in Tables 3 and 4.

  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 (9)

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 having a nominal average functional group number of 3, a glycol (b3) having a molecular weight of less than 150, and a triol (b4) having a molecular weight of less than 500,
The content of the organic polyisocyanate (a1) in the resin obtained from (A) and (B) is 0.8 to 1.2 mmol / g, and the crosslinking agent concentration is 0.11 to 0.16 mmol / g. A polyurethane elastomer-forming composition for casting, characterized by having high resilience and low strain. 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. The molar ratio of (b2) and triol (b4) having a molecular weight of less than 500 in the curing agent (B) is (b2) / (b4) = 60/40 to 99/1. The polyurethane elastomer-forming composition for casting as described. Triol (b4) having a molecular weight of less than 500 is trimethylol.

The polyurethane elastomer-forming composition for casting according to any one of claims 1 to 5, which is propane. A roll member comprising the polyurethane elastomer for casting according to any one of claims 1 to 6. A glass run for automobiles comprising the polyurethane elastomer for casting according to any one of claims 1 to 6. The manufacturing method of the polyurethane elastomer for casting in any one of Claim 1 to 6.