JP2018095766A - Polyurethane elastomer forming composition, and industrial machinery component therewith - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermosetting polyurethane elastomer forming composition for obtaining amorphous thermosetting polyurethane elastomer having JIS-A hardness of 75 to 90 without using 4,4'-diamino-3-3'-dichlorodiphenylmethane and aromatic amine and irrespective of a molding temperature.SOLUTION: A thermosetting polyurethane elastomer forming composition contains isocyanate group-terminated urethane prepolymer (A) and hydroxyl group-terminated curing agent and (B) and satisfies all conditions of the following (1) to (4). (1) The hydroxyl group-terminated curing agent (B) contains diol (B1) having a number-average molecular weight of 60 to 200, and triol (B2) having the number average molecular weight of 700 to 1500, (2) an amount of the diol (B1) having the number average molecular weight of 60 to 200 contained in the thermosetting polyurethane elastomer composition is 0.40 to 0.55 mmol/g, (3) an amount of the triol (B2) having the number average molecular weight of 700 to 1500 contained in the thermosetting polyurethane elastomer composition is 0.1 mmol/g or larger, and (4) when the isocyanate group-terminated urethane polymer (A) and the hydroxyl group-terminated curing agent (B) are blended, the isocyanate groups are excessively blended by 0.05 to 0.3 mmol/g relative to the hydroxyl groups.SELECTED DRAWING: None

Description

  The present invention relates to a thermosetting polyurethane elastomer-forming composition used for members of industrial machine parts.

  Thermosetting polyurethane elastomers have very high durability because of high modulus, high breaking strength, low wear, and low strain, and are suitably used as members of industrial machine parts.

  Generally, a thermosetting polyurethane elastomer used for a member of an industrial machine component was obtained by mixing a main agent composed of an isocyanate group-containing component and a curing agent composed of an active hydrogen group-containing component with a mixing head of a casting machine. It can be manufactured by pouring the mixed solution into a mold and heating and curing (urethanization reaction) of the mixed solution in the mold.

  As a component forming a composition for molding a thermosetting polyurethane elastomer, an isocyanate group-terminated urethane prepolymer (hereinafter abbreviated as “NCO group-terminated urethane prepolymer”) composed of isocyanate and polyol, polyol and polyamine are used. Generally, a method in which an active hydrogen group terminal curing agent composed of the above is mixed and heat-cured is used.

  When obtaining a thermosetting polyurethane elastomer having a JIS-A hardness of 65 to 75 degrees, for example, diphenylmetadiisocyanate (hereinafter abbreviated as “MDI”) and isocyanate as butylenadipate (hereinafter abbreviated as “PBA”) as the isocyanate component. NCO group-terminated urethane prepolymer and a polyol component, 1,4-butanediol (hereinafter abbreviated as “1,4-BG”), trimethylolpropane (hereinafter abbreviated as “TMP”) and PBA were mixed. A hydroxyl group terminal curing agent using a hydroxyl group as an active hydrogen group (hereinafter abbreviated as “OH group terminal curing agent”) is preferably used. When obtaining a thermosetting polyurethane elastomer having a JIS-A hardness of 70 to 98 degrees, for example, an NCO group comprising tolylene diisocyanate (hereinafter abbreviated as “TDI”) and polytetramethylene glycol (hereinafter abbreviated as “PTMG”). An amino group terminal curing agent (hereinafter referred to as “NH2 group terminal curing”) using an amino group such as a terminal urethane prepolymer and 4,4′-diamino-3,3′-dichlorodiphenylmethane (hereinafter abbreviated as “MOCA”) as an active hydrogen group. (Abbreviated as “agent”) is preferably used.

However, the thermosetting polyurethane elastomer molded product obtained as described above is selectively used depending on the hardness required as a member of industrial machine parts. Until now, especially when a hardness of JIS-A hardness of 75 degrees or more is required, for example, an NCO group-terminated urethane prepolymer composed of TDI and PTMG described later and MOCA as a NH ₂ group-end curing agent may be used. It was mainstream. However, it became pointed out about the carcinogenicity of MOCA, and aromatic diamines such as diethyltoluenediamine, diisopropyltoluenediamine, and dimethylthiotoluenediamine were proposed as prescriptions using alternative NH ₂ group terminal curing agents. (Patent Documents 1 and 2). In addition, for example, using the above-mentioned NCO group-terminated urethane prepolymer composed of MDI and polyol and OH group-end curing agent mainly composed of 1,4-BG and TMP, the blending weight ratio of 1,4-BG and TMP Has been proposed in the range of 60/40 to 98/2 (Patent Documents 3 and 4).
However, the aromatic diamine used as an alternative to the above-mentioned MOCA is not only expensive but also has insufficient properties for the resulting elastomer. Further, when the blending weight ratio of 1,4-BG and TMP is in the range of 60/40 to 98/2, the hardness increases as the blending ratio of 1,4-BG increases, but the resulting elastomer May crystallize and become cloudy. Crystallization is easily affected by the curing temperature, and unevenness in hardness (difference in hardness in the same elastomer) occurs due to the difference in crystallinity. Even if the mold temperature is adequately controlled, the crystallinity differs due to the difference in the amount of heat stored in the reaction heat due to the difference in thickness from the shape of the molded product, causing unevenness in hardness and high demands required for industrial machine parts There are many cases where I cannot answer.

JP 7-292237 A JP 2013-159859 A JP 2007-11047 A JP 2010-247934 A

  The present invention has been made based on the circumstances as described above, and the object thereof is not dependent on the molding temperature without using MOCA and aromatic amine, and has a JIS-A hardness of 75 to 90, and non- It is to provide a thermosetting polyurethane elastomer-forming composition for obtaining a crystalline thermosetting polyurethane elastomer.

  As a result of repeated investigations by the present inventors, the thermosetting polyurethane elastomer-forming composition containing the isocyanate group-terminated urethane prepolymer (A) and the hydroxyl group-terminated curing agent (B) and satisfying a specific condition, It was found that the problem can be solved, and the present invention has been achieved.

  That is, the present invention includes the following embodiments “I” to “VI”.

"I" is a thermosetting polyurethane elastomer-forming composition comprising an isocyanate group-terminated urethane prepolymer (A) and a hydroxyl group-terminated curing agent (B), all of the following conditions (1) to (4) A thermosetting polyurethane elastomer-forming composition characterized by satisfying.
(1) The hydroxyl group terminal curing agent (B) contains a diol (B1) having a number average molecular weight of 60 to 200 and a triol (B2) having a number average molecular weight of 700 to 1500. (2) Thermosetting polyurethane elastomer forming property. The amount of diol (B1) having a number average molecular weight of 60 to 200 contained in the composition is 0.40 to 0.55 mmol / g. (3) Number average contained in the thermosetting polyurethane elastomer-forming composition The amount of triol (B2) having a molecular weight of 700 to 1500 is 0.1 mmol / g or more,
(4) When the isocyanate group-terminated urethane prepolymer (A) and the hydroxyl group-end curing agent (B) are blended, the isocyanate group is blended in an excess of 0.05 to 0.3 mmol / g with respect to the hydroxyl group.

  “II” The thermosetting polyurethane elastomer-forming composition as described in “I” above, wherein the triol (B2) having a number average molecular weight of 700 to 1500 is a solid at room temperature.

  The “III” thermosetting polyurethane elastomer-forming composition further contains a triol (B4) other than (B2), and the total amount of (B2) and (B4) is 0.1 to 0.2 mmol / The thermosetting polyurethane elastomer-forming composition as described in "I" or "II" above, which is g.

  “IV” is a cured product of the thermosetting polyurethane elastomer-forming composition according to any one of “I”, “II”, and “III”, and has a JIS-A hardness of 75 to 90 degrees, and A thermosetting polyurethane elastomer characterized by being amorphous.

  "V" Industrial machine parts using the thermosetting polyurethane elastomer described in "VI" above.

  “VI” The thermosetting polyurethane elastomer-forming composition described in “I”, “II” or [III] is heat-cured at 90 to 150 ° C., and has a JIS-A hardness of 75 to A method for producing a thermosetting polyurethane elastomer that is 90 degrees and is amorphous.

  In addition, the normal temperature in this invention means 5-35 degreeC.

  By using the thermosetting polyurethane elastomer-forming composition of the present invention as a member of an industrial machine part, it has both the work safety that could not be achieved in the past and the necessary and sufficient hardness, and the properties of an OH group terminal curing agent ( The thermosetting polyurethane elastomer for members of industrial machine parts having stable characteristics can be obtained without impairing the compatibility) and without causing unevenness in hardness.

The thermosetting polyurethane elastomer-forming composition of the present invention is a thermosetting polyurethane elastomer-forming composition containing an NCO group-terminated urethane prepolymer (A) and an OH group-terminal curing agent (B), It is characterized by satisfying all the conditions (1) to (4).
(1) The hydroxyl group terminal curing agent (B) contains a diol (B1) having a number average molecular weight of 60 to 200 and a triol (B2) having a number average molecular weight of 700 to 1500. (2) Thermosetting polyurethane elastomer forming property. The amount of diol (B1) having a number average molecular weight of 60 to 200 contained in the composition is 0.40 to 0.55 mmol / g. (3) Number average contained in the thermosetting polyurethane elastomer-forming composition The amount of triol (B2) having a molecular weight of 700 to 1500 is 0.1 mmol / g or more,
(4) When the isocyanate group-terminated urethane prepolymer (A) and the hydroxyl group-end curing agent (B) are blended, the isocyanate group is blended in an excess of 0.05 to 0.3 mmol / g with respect to the hydroxyl group.

  The NCO group-terminated urethane prepolymer (A) used in the present invention is not particularly limited as long as it can be prepared from the polyisocyanate (A1) and the polyol (A2). Moreover, you may add reaction inhibitor etc. as needed. The NCO content of the NCO group-terminated urethane prepolymer (A) is preferably 5 to 25% by weight, particularly preferably 7 to 12% by weight. When the NCO content is lower than 5% by weight, the viscosity of the prepolymer is mainly increased, and the flowability of the urethane resin may be remarkably deteriorated during casting. If it is higher than 25% by weight, the stability of properties during storage and use will be extremely poor, and it will be difficult to obtain stable industrial machine parts, leading to defective molding. There is a risk of becoming unsuitable as a terminal urethane prepolymer.

  Although there is no restriction | limiting in particular as a manufacturing method of the NCO group terminal urethane prepolymer (A) used for this invention, The following manufacturing methods are preferable. The polyisocyanate (A1) and the reaction inhibitor are charged into the stirring vessel and stirred, and then the polyol (A2) is charged and stirred while maintaining the temperature in the vessel at 40 to 70 ° C. Subsequently, the isocyanate group-terminated urethane prepolymer (A) can be obtained by proceeding with the urethanization reaction for about 2 to 5 hours while keeping the temperature in the stirring vessel at 70 to 90 ° C.

  The polyisocyanate (A1) used for this invention will not be specifically limited if there exists an effect of this invention. From the viewpoint of mechanical properties and reaction control, at least one kind is preferably selected from aromatic diisocyanates, and 4,4'-diphenylmethane diisocyanate is particularly preferable.

<Polyisocyanate>
Specific examples of the polyisocyanate include aliphatic diisocyanate, alicyclic diisocyanate, aromatic diisocyanate, and araliphatic diisocyanate.

  Examples of the aliphatic diisocyanate include hexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, 2,2,4-trimethylhexamethylene-1,6- Examples include diisocyanate and 2,4,4-trimethylhexamethylene-1,6-diisocyanate.

  Examples of the alicyclic diisocyanate include isophorone diisocyanate, cyclohexyl diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated trimethylxylylene diisocyanate.

  Aromatic diisocyanates include 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 4,4′-dibenzyl diisocyanate, 1 , 5-naphthylene diisocyanate, paraphenylene diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate and the like.

  Examples of the araliphatic diisocyanate include orthoxylylene diisocyanate, metaxylylene diisocyanate, paraxylylene diisocyanate, and tetramethylxylylene diisocyanate.

  In addition, urethane-modified products, urea-modified products, carbodiimide-modified products, uretonimine-modified products, uretdione-modified products, isocyanurate-modified products, allophanate-modified products, etc. can be used.

  The polyol (A2) used in the present invention is not particularly limited as long as the effects of the present invention are exhibited. However, from the viewpoint of mechanical properties and glass transition temperature, the average functional group number is 2.0 to 2.2, the number It is preferable that at least one selected from polyester polyols having an average molecular weight of 250 to 5000, polycaprolactone polyols, polyether polyols, and polycarbonate polyols. In addition, a monomer polyol can also be used together as needed. The monomer polyol in the present invention is a compound having less than 2 bonding groups such as an ester bond, an ether bond, and a carbonate bond.

<Polyester polyol>
Specific examples of the polyester polyol include, for example, phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, succinic acid, tartaric acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, glutaconic acid, and azelaic acid. , Sebacic acid, 1,4-cyclohexyl dicarboxylic acid, α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethylglutaric acid, α, β-diethylsuccinic acid, maleic acid, fumaric acid, etc. An acid or one of these anhydrides, and the like, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol , Dimer acid diol, bisphenol A ethylene oxide and propylene oxide adducts, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc. What is obtained from the polycondensation reaction with the above can be mentioned. In addition, a polyester-amide polyol obtained by replacing a part of the low molecular polyol with a low molecular polyamine such as hexamethylene diamine, isophorone diamine or monoethanolamine or a low molecular amino alcohol can also be used.

<Polycaprolactone polyol>
Specific examples of the polycaprolactone polyol include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1, 5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol , Neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, ethylene oxide and propylene oxide adducts of bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol, Glycerin, One or more types of low molecular weight polyols having a molecular weight of 500 or less such as dimethylolpropane and pentaerythritol are used as initiators, such as ε-caprolactone, β-butyrolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, etc. Mention may be made of polycaprolactone polyols obtained by ring-opening addition of cyclic esters.

<Polyether polyol>
Specific examples of the polyether polyol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1, 5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol , Neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin, trimethylolpropane, pentaerythritol Small molecules such as Initiates compounds having 2 or more, preferably 2-3 active hydrogen groups such as diols or low molecular weight polyamines such as ethylenediamine, propylenediamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine, etc. As an agent, polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, etc., or alkyl glycidyl ethers such as methyl glycidyl ether, aryl glycidyl ethers such as phenyl glycidyl ether And polyether polyols obtained by ring-opening polymerization of cyclic ether monomers such as tetrahydrofuran.

<Polycarbonate polyol>
Specific examples of the polycarbonate polyol include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5 -Pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, Neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, ethylene oxide or propylene oxide adduct of bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin The One or more kinds of low molecular polyols such as methylolpropane and pentaerythritol, dialkyl carbonates such as dimethyl carbonate and diethyl carbonate, alkylene carbonates such as ethylene carbonate and propylene carbonate, diphenyl carbonate, dinaphthyl carbonate, dianthryl carbonate, di Examples thereof include those obtained from a dealcoholization reaction or a dephenol reaction with diaryl carbonates such as phenanthryl carbonate, diindanyl carbonate, and tetrahydronaphthyl carbonate.

  In addition, the polyol (A2) can be used alone or in combination of two or more of polyolefin polyol, acrylic polyol, silicone polyol, castor oil-based polyol, fluorine-based polyol, and monomer polyol as long as the performance does not deteriorate.

<Polyolefin polyol>
Specific examples of the polyolefin polyol include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene and the like.

<Acrylic polyol>
Examples of the acrylic polyol include acrylic acid ester and / or methacrylic acid ester (hereinafter referred to as (meth) acrylic acid ester), acrylic acid hydroxy compound having at least one hydroxyl group in the molecule and / or methacrylic acid which can be a reaction point. Examples include an acid hydroxy compound (hereinafter referred to as a (meth) acrylic acid hydroxy compound) and a polymerization initiator, which are copolymerized with an acrylic monomer using thermal energy, light energy such as ultraviolet rays or electron beams, and the like.

<Silicone polyol>
Specific examples of silicone polyols include, for example, a vinyl group-containing silicone compound obtained by polymerizing γ-methacryloxypropyltrimethoxysilane and the like, and α, ω-dihydroxypolydimethylsiloxane having at least one terminal hydroxyl group in the molecule, α And polysiloxanes such as ω-dihydroxypolydiphenylsiloxane.

<Castor oil-based polyol>
Specific examples of the castor oil-based polyol include linear or branched polyester polyols obtained by a reaction between a castor oil fatty acid and a polyol. Dehydrated castor oil, partially dehydrated castor oil partially dehydrated, hydrogenated castor oil added with hydrogen, and the like can also be used.

<Fluorine-based polyol>
Specific examples of the fluorine-based polyol include linear or branched polyols obtained by a copolymerization reaction using a fluorine-containing monomer and a monomer having a hydroxy group as essential components. Here, the fluorine-containing monomer is preferably a fluoroolefin, for example, tetrafluoroethylene, chlorotrifluoroethylene, trichlorofluoroethylene, hexafluoropropylene, vinylidene fluoride, vinyl fluoride, trifluoromethyl trifluoroethylene. Etc. Examples of the monomer having a hydroxyl group include hydroxyalkyl vinyl ethers such as hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether and cyclohexanediol monovinyl ether, hydroxyalkyl allyl ethers such as 2-hydroxyethyl allyl ether, and hydroxyalkyl vinyl crotonates. Examples thereof include hydroxyl group-containing vinyl carboxylates such as, monomers having hydroxyl groups such as allyl esters, and the like.

<Monomer polyol>
Specific examples of the monomer polyol include, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5- Pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neo Pentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc. Can be mentioned.

  The reaction inhibitor used in the present invention is not particularly limited as long as the effects of the present invention are exhibited. Specific examples of the reaction inhibitor include phosphite esters, acidic phosphate esters, polyoxyethylene alkyl ether phosphates, and the like. Examples of phosphite esters include triphenyl phosphate, tridecyl phosphate, and dibutyl hydrogen phosphate. Examples of the acidic phosphate ester include butyl acid phosphate, 2-ethylhexyl acid phosphate, and isodecyl acid phosphate. Examples of the polyoxyethylene alkyl ether phosphoric acid system include di (C12-15) pares-2 phosphoric acid, di (C12-15) -pares tetraphosphoric acid, di (C12-15) -palace 6 phosphoric acid, di (C12 -15) -Palace 8-phosphate, di (C12-15) -Palace 10-phosphate, phosphoric acid (mono, di) polyethylene glycol (3EO) C10-14 alcohol, polyoxyethylene tridecyl ether phosphate, phosphorus Acid (mono, di) polyethylene glycol (4E0) 4-nonylphenyl and the like.

  The OH group terminal curing agent (B) used in the present invention can be prepared from at least one kind of diol (B1) having a number average molecular weight of 60 to 200 and at least one kind of triol (B2) having a number average molecular weight of 700 to 1500. There are no restrictions. Also, a diol (B3) other than the number average molecular weight 60 to 200 and a triol (B4) other than the number average molecular weight 700 to 1500 can be used in combination. In addition, you may add a catalyst etc. as needed.

  The amount of the diol (B1) having a number average molecular weight of 60 to 200 contained in the thermosetting polyurethane elastomer-forming composition is 0.40 to 0.55 mmol / g, and the triol (B2) having a number average molecular weight of 700 to 1500. Is 0.1 mmol / g or more. Moreover, when using triol (B4) other than number average molecular weight 700-1500 together, it is preferable that the quantity of all the triol components (B2 + B4) is 0.1-0.2 mmol / g.

  When the amount of the diol (B1) having a number average molecular weight of 60 to 200 contained in the thermosetting polyurethane elastomer-forming composition is less than 0.40 mmol / g, the hardness of the resulting cured product is reduced to 0.55 mmol. When it exceeds / g, although the hardness of the obtained cured product is high, it is crystallized (white turbidity) and deviates from the object of the present invention. When the amount of triol (B2) having a number average molecular weight of 700 to 1500 contained in the thermosetting polyurethane elastomer-forming composition is less than 0.1 mmol / g, the resulting cured product crystallizes (white turbidity). When the content of all triol components exceeds 0.2 mmol / g, the resulting hardness is low, which is not the object of the present invention.

  Diol (B1) having a number average molecular weight of 60 to 200, triol (B2) having a number average molecular weight of 700 to 1500, diol (B3) other than the number average molecular weight of 60 to 200, and triol (B4) other than the number average molecular weight of 700 to 1500 Can be arbitrarily selected from the aforementioned polyols (A2).

  Among them, the triol (B2) having a number average molecular weight of 700 to 1500 is particularly preferably a solid at room temperature. In the case of a normal temperature solid, the OH group terminal curing agent obtained by mixing a diol (B1) having a number average molecular weight of 60 to 200 is solid at normal temperature and has excellent storage stability. When the triol (B2) having a number average molecular weight of 700 to 1500 is liquid at room temperature, the triol (B2) is liquid at room temperature, but the compatibility with the diol (B1) having a number average molecular weight of 60 to 200 is deteriorated, resulting in clouding or phase separation. In use, stirring and mixing are required in addition to heating and melting, and handling may be difficult.

  A catalyst can be added to the OH group terminal curing agent (B) used in the present invention, if necessary. Although a catalyst will not be specifically limited if there exists an effect of invention, the catalyst which mainly accelerates | stimulates a urethanation reaction from a viewpoint of improving hardness and mechanical physical property is preferable. As the urethanization catalyst, for example, an amine catalyst, an imidazole catalyst, a metal catalyst, or the like can be used. In addition, if necessary, a catalyst for promoting the nucleation reaction and a catalyst for promoting the allophanatization reaction can be used in combination or alone.

<Urethane catalyst for polyurethane>
The urethane urethanization catalyst used in the urethanization reaction can be appropriately selected from known catalysts, and specific examples of the amine catalyst include, for example, triethylenediamine, 2-methyltriethylenediamine, N, N , N ′, N′-tetramethylethylenediamine, N, N, N ′, N′-tetramethylpropylenediamine, N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine, N, N, N ′, N ″, N ″ -pentamethyl- (3-aminopropyl) ethylenediamine, N, N, N ′, N ″, N ″ -pentamethyldipropylenetriamine, N, N, N ′, N′-tetramethylhexamethylenediamine Bis (2-dimethylaminoethyl) ether, dimethylethanolamine, dimethylisopropanolamine, dimethylaminoethoxy Ethanol, N, N-dimethyl-N ′-(2-hydroxyethyl) ethylenediamine, N, N-dimethyl-N ′-(2-hydroxyethyl) propanediamine, bis (dimethylaminopropyl) amine, bis (dimethylaminopropyl) ) Isopropanolamine and the like can be mentioned.

  Specific examples of the imidazole-based catalyst include, for example, 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethylaminopropylimidazole, N, N-dimethylhexanolamine, N-methyl- N ′-(2-hydroxyethyl) piperazine, 1- (2-hydroxyethyl) imidazole, 1- (2-hydroxypropyl) imidazole, 1- (2-hydroxyethyl) -2-methylimidazole, 1- (2- Hydroxypropyl) -2-methylimidazole and the like.

  As a specific example of the diazacycloamine salt system, for example, diazabicycloamine is 1,8-diazabicyclo [5.4.0] -undecene-7 or 1,5-diazabicyclo [4.3.0] -nonene. -5, and salts with octylic acid, oleic acid, phthalic acid, maleic acid, formic acid, acetic acid, boric acid, p-toluenesulfonic acid, phenol, triazole and the like can be used.

  Specific examples of the metal catalyst system include stannous diacetate, stannous dioctoate, stannous dioleate, stannous dilaurate, dibutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, dioctyltin dilaurate and the like. Examples thereof include an organic tin catalyst, nickel octylate, nickel naphthenate, cobalt octylate, cobalt naphthenate, bismuth octylate, and bismuth naphthenate.

<Nuration catalyst for polyurethane>
The polyurethane nurating catalyst used in the nurating reaction can be appropriately selected from known catalysts. Specific examples thereof include triethylamine, N-ethylpiperidine, N, N′-dimethylpiperazine, N -Tertiary amines such as ethyl morpholine, Mannich base of phenolic compounds, tetramethylammonium bicarbonate, methyltriethylammonium bicarbonate, ethyltrimethylammonium bicarbonate, propyltrimethylammonium bicarbonate, butyltrimethylammonium bicarbonate Salt, pentyltrimethylammonium hydrogencarbonate, hexyltrimethylammonium hydrogencarbonate, heptyltrimethylammonium hydrogencarbonate, octyltrimethylammonium hydrogencarbonate, nonyltrimethylammonium Bicarbonate, decyltrimethylammonium bicarbonate, undecyltrimethylammonium bicarbonate, dodecyltrimethylammonium bicarbonate, tridecyltrimethylammonium bicarbonate, tetradecyltrimethylammonium bicarbonate, heptadecyltrimethylammonium bicarbonate, Hexadecyltrimethylammonium bicarbonate, heptadecyltrimethylammonium bicarbonate, octadecyltrimethylammonium bicarbonate, (2-hydroxypropyl) trimethylammonium bicarbonate, hydroxyethyltrimethylammonium bicarbonate, 1-methyl-1-azania -4-azabicyclo [2.2.2] octanium bicarbonate, 1,1-dimethyl-4-methylpiperidinium bicarbonate, etc. Quaternary ammonium bicarbonate, tetramethylammonium carbonate, methyltriethylammonium carbonate, ethyltrimethylammonium carbonate, propyltrimethylammonium carbonate, butyltrimethylammonium carbonate, pentyltrimethylammonium carbonate, hexyltrimethylammonium carbonate, heptyltrimethyl Ammonium carbonate, octyltrimethylammonium carbonate, nonyltrimethylammonium carbonate, decyltrimethylammonium carbonate, undecyltrimethylammonium carbonate, dodecyltrimethylammonium carbonate, tridecyltrimethylammonium carbonate, tetradecyltrimethylammonium carbonate, hepta Decyltrimethylammonium carbonate, hexadecyltrimethylammonium Acid salt, heptadecyltrimethylammonium carbonate, octadecyltrimethylammonium carbonate, (2-hydroxypropyl) trimethylammonium carbonate, hydroxyethyltrimethylammonium carbonate, 1-methyl-1-azania-4-azabicyclo [2,2, 2] of octanium carbonate, quaternary ammonium carbonate such as 1,1-dimethyl-4-methylpiperidinium carbonate, hydroxyalkylammonium such as trimethylhydroxypropylammonium, trimethylhydroxypropylammonium, triethylhydroxyethylammonium Alkali metal salts of carboxylic acids such as hydroxide, weak organic acid salts, acetic acid, propionic acid, butyric acid, caproic acid, capric acid, valeric acid, octylic acid, myristic acid, naphthenic acid Etc.

<Allophanatization catalyst for polyurethane>
The allophanatization catalyst for polyurethane used in the allophanatization reaction can be appropriately selected from known catalysts, and for example, a metal salt of a carboxylic acid can be used.

  Specific examples of the carboxylic acid include, for example, acetic acid, propionic acid, butyric acid, caproic acid, octylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, 2-ethylhexanoic acid and other saturated aliphatic carboxylic acids, cyclohexanecarboxylic acid , Saturated monocyclic carboxylic acids such as cyclopentanecarboxylic acid, saturated polycyclic carboxylic acids such as bicyclo [4.4.0] decane-2-carboxylic acid, mixtures of the above-mentioned carboxylic acids such as naphthenic acid, oleic acid, linol Monocarboxylic acids such as acid, linolenic acid, unsaturated fatty carboxylic acid such as soybean oil fatty acid and tall oil fatty acid, aromatic aliphatic carboxylic acid such as diphenylacetic acid, aromatic carboxylic acid such as benzoic acid and toluic acid; phthalic acid , Isophthalic acid, terephthalic acid, naphthalene dicarboxylic acid, succinic acid, tartaric acid, oxalic acid, malonic acid, Phosphoric acid, adipic acid, pimelic acid, suberic acid, kurtaconic acid, azelaic acid, sebacic acid, 1,4-cyclohexyldicarboxylic acid, α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethylglutaric acid , Α, β-diethylsuccinic acid, maleic acid, fumaric acid, trimellitic acid, pyrocarboxylic acid and other polycarboxylic acids.

  Examples of the metal constituting the metal salt of carboxylic acid include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium, calcium and barium, other typical metals such as tin and lead, manganese, iron and cobalt , Transition metals such as nickel, copper, zinc and zirconium. These metal carboxylates can be used alone or in combination of two or more.

  In addition, examples of the alkanolamine include N, N, N, N′-trimethylaminoethylethanolamine and N, N-dimethylaminoethoxyethanol.

  The amount of the urethanization catalyst used is in the range of 0.001 to 0.5% by weight with respect to the total weight of the NCO group-terminated urethane prepolymer (A) and the OH group-end curing agent (B). From the viewpoint of easy reaction control, it is more preferably used in the range of 0.005 to 0.3% by weight.

  In the present invention, if necessary, an antioxidant, an antifoaming agent, an ultraviolet absorber and the like can be introduced and used as an additive in the forming composition.

  In the present invention, the blending ratio of the NCO group-terminated urethane prepolymer (A) and the OH group-end curing agent (B) is in the range of 0.05 to 0.3 mmol / g of isocyanate groups with respect to the hydroxyl groups contained therein. The ratio becomes excessive. When the excess amount of isocyanate groups is less than 0.05 mmol / g, physical properties and particularly heat resistance are reduced. On the other hand, if it exceeds 0.3 mmol / g, it is difficult to polymerize in a short time, and the mold release time is long, leading to a decrease in productivity, and the mold release hardness is deformed to serve as an industrial machine part. Absent.

  The thermosetting polyurethane elastomer of the present invention is a cured product of the above-described thermosetting polyurethane elastomer-forming composition of the present invention, and has a JIS-A hardness of 75 to 90 degrees and is amorphous. Is the feature.

  The thermosetting polyurethane elastomer of the present invention can be obtained by subjecting the above-described thermosetting polyurethane elastomer-forming composition of the present invention to a thermosetting treatment at 90 to 150 ° C.

  The thermosetting polyurethane elastomer of the present invention is suitably used for industrial machine parts.

  In the present invention, using the thermosetting polyurethane elastomer-forming composition described so far, a curing process (specifically, a process of promoting curing by heating) is performed as a process in the mold, A thermoset polyurethane elastomer molded article (industrial machine part) having urethanized, nurated and allophanated bonds is produced.

  In this case, as a method for producing a thermosetting polyurethane elastomer molded product according to the present invention using the forming composition according to the present invention, it is preferably produced by a method including the following steps. .

Step (1):
NCO group-terminated urethane prepolymer (A) and OH group-end curing agent (B). However, if the OH group-end curing agent (B) does not contain a catalyst in advance, the catalyst is added separately and mixed uniformly. A sex composition is prepared. In addition, when air is involved and bubbles are observed, the bubbles are removed by vacuum defoaming or the like. These steps are preferably performed using a dedicated polyurethane casting machine.

Step (2):
Immediately after mixing the formable composition into a preheated mold, the mold is poured into the mold (casting), and the formable composition is heat-cured in the mold (specifically, cured by heating). Reaction). In this case, the temperature of the mold is preferably in the range of 80 to 150 ° C. from the viewpoint that the urethanization reaction is an easy and reliable condition.

Step (3):
After the forming composition is cured, the cured product (that is, the thermosetting polyurethane elastomer molded product) is taken out from the mold (demolding). In the present invention, the time required from casting to demolding is not particularly limited. However, from the viewpoint of productivity of the thermosetting polyurethane elastomer intended by the present invention, the amount of catalyst and molding It is preferable that the preheating temperature of the mold is adjusted to be in the range of 30 to 600 seconds.

Step (4):
After curing, it is preferable to perform an aging treatment at room temperature for one week after demolding the thermosetting polyurethane elastomer molded product (industrial machine part).

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited at all by these. In Examples and Comparative Examples, “%” means “% by weight” unless otherwise specified.

Examples 1-6, Comparative Examples 1-6
According to the weight ratio shown in Table 1 and Table 2, various polyisocyanates (A1), reaction inhibitors, and antioxidants were charged and stirred in a 5 L stirring vessel filled with nitrogen. Thereafter, various polyols (A2) were charged and stirred according to the weight ratio while maintaining the temperature in the stirring vessel at 40 to 70 ° C. Subsequently, an antifoaming agent is added according to the weight ratio, and various NCO group-terminated urethane prepolymers (A )

  Further, according to the weight ratios shown in Tables 1 and 2, various diols (B1, B3) and various triols (B2, B4) were charged and stirred in a 5 L stirring vessel filled with nitrogen. Then, while maintaining the temperature in the stirring vessel at 40 to 70 ° C., a catalyst and an antifoaming agent are added according to the weight ratio, and the various OH group terminal curing agents (B) are mixed and stirred for about 1 to 3 hours. Obtained.

  Next, according to the composition (weight ratio) shown in Table 1 and Table 2, the OH containing the NCO group-terminated urethane prepolymer (A) preliminarily kept at 70 to 90 ° C. and the catalyst preliminarily kept at 40 to 60 ° C. The thermosetting polyurethane elastomer-forming composition of the present invention was prepared by mixing the base terminal curing agent (B) with a two-component mixed urethane casting machine, and this composition was preheated to a curing temperature in advance. The mold was injected into a mold for sheet molding having a size of 180 mm in length, 250 mm in width, and 2 mm in thickness, and a mold for compression set having a size of 29.0 mm in diameter and 12.5 mm in thickness. The composition was heated and cured in a minimum time that could be taken out (demolded) in the mold, and the molded product was quickly demolded to obtain the polyurethane elastomer molded product of the present invention.

Abbreviations of raw materials used in Table 1 and Table 2 are as follows.

"Isocyanate (A1)"
(1) Millionate MT; 4,4′-MDI, NCO content = 33.5% (manufactured by Tosoh Corporation)
"Polyol (A2)"
(2) Nipponran 3027; polybutylene adipate, average number of functional groups = 2.0, hydroxyl value = 44.9 KOHmg / g (manufactured by Tosoh Corporation)
(3) Nipponran 4040; polyethylene adipate, average number of functional groups = 2.0, hydroxyl value = 56.1 KOHmg / g (manufactured by Tosoh Corporation)
(4) PTMG-1000; polytetramethylene glycol, average number of functional groups = 2.0, hydroxyl value = 112.0 KOHmg / g (manufactured by Mitsubishi Chemical Corporation).

"Diol (B1), (B3)"
(5) Ethylene glycol; ethylene glycol, hydroxyl value = 1,809 KOHmg / g (Mitsubishi Chemical Corporation)
(6) 1,4-butanediol; 1,4-butanediol, hydroxyl value = 1,245 KOHmg / g (manufactured by Mitsubishi Chemical Corporation)
(7) 1,6-hexanediol; 1,6-hexanediol, hydroxyl value = 950 KOHmg / g (manufactured by Ube Industries)
(8) Nipponran 4009; polybutylene adipate, average number of functional groups = 2.0, hydroxyl value = 112.0 KOHmg / g (manufactured by Tosoh Corporation).

"Triol (B2), (B4)"
(9) Plaxel 305; polycaprolactone polyol, average number of functional groups = 3.0, hydroxyl value = 306.1 KOHmg / g (manufactured by Daicel)
(10) Plaxel 308; polycaprolactone polyol, average number of functional groups = 3.0, hydroxyl value = 198.0 KOHmg / g (manufactured by Daicel)
(11) Plaxel 312; polycaprolactone polyol, average number of functional groups = 3.0, hydroxyl value = 134.7 KOHmg / g (manufactured by Daicel)
(12) Plaxel 320; polycaprolactone polyol, average number of functional groups = 3.0, hydroxyl value = 84.2 KOHmg / g (manufactured by Daicel)
(13) Kuraray polyol F-1010; polyester polyol (MPD / TMP / adipic acid), average number of functional groups = 3.0, hydroxyl value = 168.3 KOH mg / g, (manufactured by Kuraray Co., Ltd.)
(14) Trimethylolpropane; trimethylolpropane, hydroxyl value = 1,247 KOHmg / g (manufactured by Mitsubishi Gas Chemical Company).

"catalyst"
(15) TOYOCAT B41; diazacycloamine salt (manufactured by Tosoh Corporation).

"Others / Additives"
(16) Reaction inhibitor: Phospholan PS-236, mono-di (C10-12) palace-5 phosphate (manufactured by Akzo Nobel)
(17) Antioxidant; Irganox 1010, pentaerythritol tetrakis [3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] (manufactured by BASF Japan)
(18) Antifoaming agent; BYK-052 (manufactured by Big Chemie Japan).

  Tables 1 and 2 show general properties of the obtained NCO group-terminated urethane prepolymer, OH group-terminated curing agent, and characteristic values of the molded sheet. Each characteristic evaluation method is as follows.

"General property value"
(1) NCO content: measured according to JIS K1603-1.
(2) Hydroxyl value: measured according to JIS K1557-1.
(3) Turbidity: measured according to JIS K0101.
(4) Storage stability: OH group terminal curing agent kept at 60 ° C. was put in 180 g in a 200 ml glass container and left at room temperature for 1 week. Thereafter, the contents were confirmed visually and the presence or absence of separation was confirmed.

"Characteristic values of forming composition (cured product)"
(1) JIS-A hardness: measured using a type A hardness meter according to JIS K7312 using a cylindrical molded product having a thickness of 12.5 mm.
(2) Tensile strength (TB), elongation rate (EB): Measurement was performed according to JIS K7312 using a sheet-like molded product having a thickness of 2 mm.
(3) Appearance: Appearance was evaluated visually using a sheet-like molded product having a thickness of 2 mm. The transparency and the presence or absence of deformation were confirmed.

  According to Examples 1-6, although it is comprised with the composition which can ensure work safety, it has necessary and sufficient hardness increase, and it does not impair the property (compatibility) of an OH group terminal hardening | curing agent, and hardness unevenness. It was possible to obtain a thermosetting polyurethane elastomer free from the above.

  Comparative Example 1 is an example in the case where a conventional 1,4-butanediol and trimethylolpropane-based OH group terminal curing agent is used, and the occurrence of turbidity of the curing agent and the obtained molded product The hardness was low and the sheet was slightly cloudy.

  Comparative Example 2 is an example in which the introduction amount of a diol having a number average molecular weight of 60 to 200 is less than 0.40 mmol / g and the introduction amount exceeds 0.2 mmol / g using a triol having a number average molecular weight of less than 700. In addition, the OH group terminal curing agent was separated into two phases at room temperature, the storage stability was poor, and the hardness of the resulting molded product was low.

  Comparative Example 3 is an example where the excess amount of isocyanate groups relative to hydroxyl groups exceeds 0.3 mmol / g when the NCO group-terminated urethane prepolymer (A) and the OH group-terminated curing agent (B) are blended. Yes, the molded product was deformed without obtaining sufficient strength during demolding. Moreover, the hardness of the molded product obtained showed a low value.

  In Comparative Example 4, when the NCO group-terminated urethane prepolymer (A) and the OH group-end curing agent (B) were blended, the excess amount of isocyanate groups relative to the hydroxyl group was less than 0.05 mmol / g, and the number average molecular weight 60 This is an example in which the amount of diol -200 exceeds 0.55 mmol / g, and the resulting molded product has high hardness, but the sheet is cloudy.

  Comparative Example 5 is an example in which the amount of triol having a number average molecular weight of 700 to 1500 is less than 0.1 mmol / g. Although the resulting molded product has a high hardness, the molded product is deformed during demolding. Indicated.

  Comparative Example 6 is an example in the case of using a triol having a number average molecular weight of more than 1500, showing poor compatibility with a diol having a number average molecular weight of 60 to 200 and a very high turbidity. For this reason, hardening confirmation was not implemented.

Claims (6)

A thermosetting polyurethane elastomer-forming composition comprising an isocyanate group-terminated urethane prepolymer (A) and a hydroxyl group-terminated curing agent (B), which satisfies all the following conditions (1) to (4): A thermosetting polyurethane elastomer-forming composition characterized by the above.
(1) The hydroxyl group terminal curing agent (B) contains a diol (B1) having a number average molecular weight of 60 to 200 and a triol (B2) having a number average molecular weight of 700 to 1500. (2) Thermosetting polyurethane elastomer forming property. The amount of diol (B1) having a number average molecular weight of 60 to 200 contained in the composition is 0.40 to 0.55 mmol / g. (3) Number average contained in the thermosetting polyurethane elastomer-forming composition The amount of triol (B2) having a molecular weight of 700 to 1500 is 0.1 mmol / g or more,
(4) When the isocyanate group-terminated urethane prepolymer (A) and the hydroxyl group-end curing agent (B) are blended, the isocyanate group is blended in an excess of 0.05 to 0.3 mmol / g with respect to the hydroxyl group. The thermosetting polyurethane elastomer-forming composition according to claim 1, wherein the triol (B2) having a number average molecular weight of 700 to 1500 is a solid at room temperature. The thermosetting polyurethane elastomer-forming composition further contains a triol (B4) other than (B2), and the total amount of (B2) and (B4) is 0.1 to 0.2 mmol / g. The thermosetting polyurethane elastomer-forming composition according to claim 1, wherein the composition is a thermosetting polyurethane elastomer-forming composition. A cured product of the thermosetting polyurethane elastomer-forming composition according to any one of claims 1 to 3, wherein the JIS-A hardness is 75 to 90 degrees and non-crystalline. Thermosetting polyurethane elastomer. An industrial machine part using the thermosetting polyurethane elastomer according to claim 4. The thermosetting polyurethane elastomer-forming composition according to any one of claims 1 to 3, which is heat-cured at 90 to 150 ° C, has a JIS-A hardness of 75 to 90 degrees, and A method for producing a thermosetting polyurethane elastomer that is crystalline.