JP7286958B2 - Thermosetting polyurethane elastomer-forming composition, thermosetting polyurethane elastomer, industrial machine part, and method for producing industrial machine part - Google Patents

Description

The present disclosure relates to thermoset polyurethane elastomer-forming compositions, thermoset polyurethane elastomers, industrial machine parts and methods of making industrial machine parts.

A thermosetting polyurethane elastomer-forming composition has a high modulus, a high breaking strength, a low wear and a low strain, and thus has a very high durability, and is suitably used as a component member of industrial machinery. . However, under severe conditions such as continuous operation, the parts and members of this industrial machine generate heat under the influence of friction, and the heat accumulates, resulting in a high temperature. When the temperature becomes high, the characteristic values of the hardened material of the parts and members of the industrial machinery change greatly, and the desired performance may not be exhibited.

Therefore, Patent Document 1 describes a polyurethane resin mixed with a lubricant consisting of a single or a mixture of two or more selected from the group of graphite, ethylene tetrafluoride, resin powder, paraffin, molybdenum disulfide, and Japanese wax. A formed wear resistant power transmission belt is disclosed.
Further, Patent Document 2 discloses a transmission belt using a composition in which a fatty alcohol ester is added to a polyurethane elastomer.
Furthermore, Patent Document 3 discloses a power transmission belt containing polyurethane into which stearic acid having a hydroxyl group or an amino group, or an oleic acid-based ester or the like is introduced.

Japanese Utility Model Laid-Open No. 57-194946 JP-A-3-346 JP-A-11-51122

However, in the power transmission belts according to Patent Documents 1 and 2, a lubricant that does not react with polyurethane is mixed with the polyurethane elastomer-forming composition, so the compatibility between these lubricants and the polyol component and/or the isocyanate component is low. Unfortunately, a non-uniform polyurethane elastomer molded product (cured product) is obtained. Furthermore, in the transmission belts of Patent Documents 1 and 2, the lubricant component may bleed or bloom, and especially when used for precision industrial machinery parts, contamination by these lubricant components may cause problems in the industrial machinery. It can occur and become a problem.
In addition, in the transmission belt according to Patent Document 3, due to the lack of carbon number in the lubricant component and the inhibition of the degree of freedom, the lubricant cannot sufficiently migrate to the surface of the polyurethane elastomer molded product, and the friction reduction is insufficient or sustained. There are many cases where you don't.

Accordingly, one aspect of the present disclosure is directed to providing a thermosetting polyurethane elastomer-forming composition that contributes to the formation of a thermosetting polyurethane elastomer having excellent durability and reduced frictional force.
Other aspects of the present disclosure are directed to providing thermosetting polyurethane elastomers with excellent durability and reduced friction, industrial machine parts, and methods of making industrial machine parts.

Each aspect of the present disclosure is shown in (1) to (4) below.
(1): an isocyanate group-terminated urethane prepolymer (A);
and a hydroxyl group terminal curing agent (B),
The isocyanate group-terminated urethane prepolymer (A) is
diphenylmethane diisocyanate (C); and
and a polyol (D) having an ether unit,
The hydroxyl value of the polyol (D) is 30 KOHmg/g or more and 90 KOHmg/g or less,
The hydroxyl group-terminated curing agent (B) contains a polyol (E) having an ester unit,
The hydroxyl value of the polyol (E) is 30 KOHmg/g or more and 310 KOHmg/g or less.
A thermosetting polyurethane elastomer-forming composition.

(2): A thermosetting polyurethane elastomer comprising a cured product of the thermosetting polyurethane elastomer-forming composition according to (1) above.

(3): including a cured product of the thermosetting polyurethane elastomer-forming composition according to (1) above,
The cured product is
JIS-A hardness is 70 ° or more and 98 ° or less,
An industrial machine part having a coefficient of dynamic friction of 0.8 or less.

(4): A method for producing an industrial machine part, comprising curing the thermosetting polyurethane elastomer-forming composition according to (1) above at 90° C. or higher and 150° C. or lower to obtain a cured product.

One aspect of the present disclosure can provide a thermosetting polyurethane elastomer-forming composition that contributes to the formation of a thermosetting polyurethane elastomer having excellent durability and reduced frictional force. Further, another aspect of the present disclosure can provide a thermosetting polyurethane elastomer having excellent durability and reduced frictional force, an industrial machine part, and a method for manufacturing the industrial machine part.

DETAILED DESCRIPTION Exemplary modes for carrying out the invention are described in detail below.

[Thermosetting polyurethane elastomer-forming composition]
A thermosetting polyurethane elastomer-forming composition according to one aspect of the present invention comprises an isocyanate group-terminated urethane prepolymer (A),
and a hydroxyl group terminal curing agent (B),
The isocyanate group-terminated urethane prepolymer (A) is
diphenylmethane diisocyanate (C); and
and a polyol (D) having an ether unit,
The hydroxyl value of the polyol (D) is 30 KOHmg/g or more and 90 KOHmg/g or less,
The hydroxyl group-terminated curing agent (B) contains a polyol (E) having an ester unit,
The hydroxyl value of the polyol (E) is 30 KOHmg/g or more and 310 KOHmg/g or less.
A thermosetting polyurethane elastomer-forming composition.

The thermosetting polyurethane elastomer-forming composition according to this embodiment is made by mixing and stirring the isocyanate group-terminated urethane prepolymer (A) and the hydroxyl group-terminated curing agent (B), and reacting (polymerizing) them to achieve compatibility. As a result, the appearance of the obtained molding becomes cloudy, and the frictional force can be reduced. This reduction in frictional force is due to the microphase separation of each component when the molding is made into a molded product, which results in the formation of fine unevenness on the contact surface of the thermosetting polyurethane elastomer molded product, and the contact between the molded product and the contact object. The inventor presumes that the area is reduced and low friction is achieved.

Next, the constituent components of the thermosetting polyurethane elastomer-forming composition according to this embodiment will be described in more detail.

<Isocyanate group-terminated urethane prepolymer (A)>
The isocyanate group-terminated urethane prepolymer (A) contains diphenylmethane diisocyanate (C) and a polyol (D) having an ether unit.

<<Diphenylmethane diisocyanate (C)>>
Diphenylmethane diisocyanate (C) includes 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 2,2'-diphenylmethane diisocyanate, and one or more of these can be used. Diphenylmethane diisocyanate (C) is not particularly limited, but 4,4'-diphenylmethane diisocyanate is particularly preferred from the viewpoint of suppressing deterioration of mechanical properties at high temperatures.
Diphenylmethane diisocyanate (C) can also be used in combination with other polyisocyanates. However, the content of diphenylmethane diisocyanate (C) in the isocyanate group-terminated urethane prepolymer (A) is preferably 60% by mass or more with respect to the total amount of isocyanate in the isocyanate group-terminated urethane prepolymer (A). , and more preferably 80% by mass or more.

<<Other polyisocyanates>>
Other polyisocyanates include, for example, hexamethylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, cyclohexyl diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated trimethylxylylene diisocyanate, and 2-methylpentane-1. ,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, 2,4,4-trimethylhexamethylene-1,6-diisocyanate and other aliphatic and cycloaliphatic diisocyanates; polymethylene polyphenyl polyisocyanate, 4, aromatic diisocyanates such as 4′-diphenyldimethylmethane diisocyanate, 4,4′-dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, paraphenylene diisocyanate, tolylene-2,4-diisocyanate and tolylene-2,6-diisocyanate; Non-yellowing diisocyanates such as ortho-xylylene diisocyanate, meta-xylylene diisocyanate, para-xylylene diisocyanate, tetramethylxylylene diisocyanate; these urethane-modified, urea-modified, carbodiimide-modified, uretonimine-modified, uretdione-modified, isocyanate modified nurate, modified allophanate; and the like.

<<polyol (D) having an ether unit>>
The polyol (D) having an ether unit has a hydroxyl value of 30 KOHmg/g or more and 90 KOHmg/g or less. The polyol (D) is not particularly limited, but from the viewpoint of the properties and quality of the resulting isocyanate group-terminated urethane prepolymer (A), the hydroxyl value is 30 KOHmg/g or more and 90 KOHmg/g or less, and , and polyols having an average number of functional groups of 2 to 3.

When the hydroxyl value is less than 30 KOH mg/g, the viscosity of the polyol itself is high, and as a result, the viscosity of the resulting isocyanate group-terminated urethane prepolymer (A) becomes too high, and castability into molds deteriorates. and difficult to use.
If the hydroxyl value exceeds 90 KOHmg/g, the appearance of the obtained molded product becomes difficult to become cloudy, and the frictional force cannot be sufficiently reduced.

When two or more polyols are used, the average hydroxyl value X _av (KOHmg/g) according to the blending ratio of the two or more polyols is used as the hydroxyl value of the polyol (D).
For example, when two types of polyol (d1) and polyol (d2) are used as the polyol (D), the hydroxyl value of the polyol (d1) is X ₁ (KOHmg/g), the blending ratio is m ₁ , and the polyol (d2) is The average hydroxyl value X _av (KOH mg/g) of polyol (D) is expressed by the following formula, where X 2 (KOH mg/g) _is the hydroxyl value and m ₂ is the compounding ratio.
Average hydroxyl value X _av = X ₁ × (m ₁ /(m ₁ + m ₂ )) + X ₂ × (m ₂ /(m ₁ + m ₂ ))

Specific examples of the polyol (D) include the following polyether polyols (d-1) and (d-2).

<<<polyol (d-1)>>>
Ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexane Diol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4 -low-molecular-weight polyols such as diol, cyclohexane-1,4-dimethanol, dimer acid diol, bisphenol A, bis(β-hydroxyethyl)benzene, xylylene glycol, glycerin, trimethylolpropane, pentaerythritol; ethylenediamine, propylene Low-molecular-weight polyamines such as diamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine, etc.; Polyether polyols obtained by addition polymerization of alkylene oxides such as propylene oxide and butylene oxide.

<<<polyol (d-2)>>>
Polyether polyols obtained by ring-opening polymerization of alkyl glycidyl ethers such as methyl glycidyl ether; aryl glycidyl ethers such as phenyl glycidyl ether; cyclic ether monomers such as tetrahydrofuran;

Further, the polyol (D) may be a polyolefin polyol, an acrylic polyol, a silicone polyol, a castor oil-based polyol, a fluorine-based polyol, or a monomer polyol, either alone or in combination of two or more, as long as the performance is not lowered. These polyols are described later.

<<Reaction control agent (G)>>
The isocyanate group-terminated prepolymer (A) is not particularly limited as long as it can be prepared from diphenylmethane diisocyanate (C) and polyol (D). Further, a reaction inhibitor (G) may be added to the isocyanate group-terminated prepolymer (A) as necessary.

The reaction inhibitor (G) is not particularly limited. Examples of the reaction inhibitor (G) include phosphite-based, acidic phosphate-based, polyoxyethylene alkyl ether phosphate-based, and the like.
Examples of the phosphite ester include triphenyl phosphate, tridecyl phosphate, dibutyl hydrogen phosphate, and the like.
Acidic phosphates include butyl acid phosphate, 2-ethylhexyl acid phosphate, isodecyl acid phosphate and the like.
Polyoxyethylene alkyl ether phosphates include di(C12-15) pareth-2 phosphate, di(C12-15) pareth 4 phosphate, di(C12-15) pareth 6 phosphate, di(C12 -15) -Paleth 8 phosphate, di(C12-15)-Paleth 10 phosphate, phosphoric acid (mono, di) polyethylene glycol (3EO) C10-14 alcohol, polyoxyethylene tridecyl ether phosphate, phosphorus Acid (mono, di) polyethylene glycol (4EO) 4-nonylphenyl and the like.

<<NCO content>>
The NCO content of the isocyanate group-terminated urethane prepolymer (A) is preferably 5% by mass or more and 25% by mass or less. When the NCO content is 5% by mass or more and 25% by mass or less, it is possible to highly suppress the viscosity of the prepolymer from becoming excessively high, and the flowability during casting is improved, and during storage and use. Since the property stability becomes better, it becomes easier to obtain stable industrial machine parts, and the occurrence of molding defects can be further suppressed.

<Method for producing isocyanate group-terminated urethane prepolymer (A)>
The method for producing the isocyanate group-terminated urethane prepolymer (A) is not particularly limited, but the following production method is preferred.
After charging diphenylmethane diisocyanate (C) and reaction inhibitor (G) into a stirring container and stirring, the polyol (D) is added and stirred while maintaining the temperature in the container at 40 to 70°C. Further, if necessary, an antioxidant and an antifoaming agent are added and stirred. Subsequently, while maintaining the temperature in the stirring vessel at 70 to 90° C., the urethanization reaction proceeds for about 2 to 5 hours, whereby an isocyanate group-terminated urethane prepolymer (A) can be obtained.

<Hydroxyl Terminal Curing Agent (B)>
A hydroxyl-terminated curing agent (B) contains a polyol (E) having an ester unit. The polyol (E) has a hydroxyl value of 30 mg KOH/g or more and 310 mg KOH/g or less.
Preferably, the hydroxyl group-terminated curing agent (B) further contains a monomer polyol (F) having a molecular weight of 300 or less.

<<polyol (E) having an ester unit>>
The polyol (E) has a hydroxyl value of 30 mg KOH/g or more and 310 mg KOH/g or less.
When the hydroxyl value is less than 30 KOH mg/g, the viscosity of the polyol itself is high, and the resulting hydroxyl terminal curing agent (B) becomes too viscous, resulting in deterioration of castability into molds and the like, making it difficult to use. it gets harder. Furthermore, in the case of the hydroxyl value terminal curing agent (B) used in combination with the monomer polyol (F) having a polyol molecular weight of 300 or less, if the hydroxyl value is less than 30 KOHmg/g, the compatibility deteriorates and becomes uneven. However, there are problems such as separation over time.
On the other hand, when the hydroxyl value exceeds 310 KOHmg/g, the appearance of the obtained molded product becomes difficult to become cloudy, and the frictional force cannot be sufficiently reduced.

When two or more polyols are used, the average hydroxyl value Y _av (KOHmg/g) according to the compounding ratio is used as the hydroxyl value of the polyol (E).
For example, when using two types of polyol (e1) and polyol (e2) as the polyol (E), the hydroxyl value of the polyol (e1) is Y ₁ (KOHmg/g), the blending ratio is n ₁ , and the polyol (e2) is The average hydroxyl value _Yav (KOHmg/g) of the polyol (E) is represented by the following formula, where the hydroxyl value is _Y2 (KOHmg/g) and the compounding ratio is _n2 .
Average hydroxyl value Y _av = Y ₁ ×(n ₁ /(n ₁ +n ₂ )) + Y ₂ ×(n ₂ /(n ₁ +n ₂ ))

The polyol (E) is not particularly limited, but from the viewpoint of the properties and quality of the hydroxyl terminal curing agent (B) and low friction, the hydroxyl value is 30 KOHmg / g or more and 310 KOHmg / g or less, and , and polyols having an average number of functional groups of 2 to 3.

Specific examples of the polyol (E) include the following polyester polyols (e-1), polycaprolactone polyols (e-2), and polycarbonate polyols (e-3).

<<<polyester polyol (e-1)>>>
Examples of the polyester polyol (e-1) include phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, succinic acid, tartaric acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and glutaconic 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 dicarboxylic acids such as; or anhydrides thereof; 4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylol Heptane, 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, trimethylolpropane, pentaerythritol; and one or more low-molecular-weight polyols having a molecular weight of 500 or less;
Polyester-amide polyols obtained by replacing part of the low-molecular-weight polyol with low-molecular-weight polyamines such as hexamethylenediamine, isophoronediamine and monoethanolamine or low-molecular-weight aminoalcohols can also be used.

<<<polycaprolactone polyol (e-2)>>>
Polycaprolactone polyol (e-2) includes, 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, xyl ε-caprolactone, β-butyrolactone, γ-butyrolactone, γ-valerolactone using one or more polyols selected from low-molecular-weight polyols having a molecular weight of 500 or less, such as lenglycol, glycerin, trimethylolpropane, and pentaerythritol, as an initiator. Polycaprolactone polyols obtained by ring-opening addition of cyclic esters such as , δ-valerolactone can be used.

<<<polycarbonate polyol (e-3)>>>
A polycarbonate polyol (e-3) can also be used as the polyol (E).
Examples of the polycarbonate polyol (e-3) 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, di Propylene 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 One or more of low-molecular-weight polyols such as glycol, glycerin, trimethylolpropane, and pentaerythritol, and dialkyl carbonates such as dimethyl carbonate and diethyl carbonate; alkylene carbonates such as ethylene carbonate and propylene carbonate; diphenyl carbonate, dinaphthyl carbonate, Diaryl carbonates such as dianthryl carbonate, diphenanthryl carbonate, diindanyl carbonate and tetrahydronaphthyl carbonate;

In addition, polyolefin polyols, acrylic polyols, silicone polyols, castor oil-based polyols, fluorine-based polyols, and monomer polyols can be used singly or in combination of two or more as the polyol (E) as long as the performance is not lowered. .

<<Polyolefin Polyol>>
Examples of polyolefin polyols include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene.

<<Acrylic Polyol>>
Examples of acrylic polyols include acrylic monomers such as acrylic acid esters and/or methacrylic acid esters [hereinafter referred to as (meth)acrylic acid esters], and acrylic acid hydroxy compounds having one or more hydroxyl groups that can serve as reaction points in the molecule and/or Alternatively, a methacrylic acid hydroxy compound (hereinafter referred to as a (meth)acrylic acid hydroxy compound) and an acrylic monomer are copolymerized. Copolymerization of acrylic monomers can be carried out by using a polymerization initiator and applying heat energy, light energy such as ultraviolet rays or electron beams, or the like.

<<<(meth)acrylic acid ester>>>
Examples of (meth)acrylic acid esters include alkyl esters having 1 to 20 carbon atoms. Examples of such (meth)acrylate esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, pentyl (meth)acrylate, ( (Meth)acrylic acids such as hexyl methacrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate and dodecyl (meth)acrylate alkyl esters; esters of (meth)acrylic acid with alicyclic alcohols such as cyclohexyl (meth)acrylate; allyl (meth)acrylate esters such as phenyl (meth)acrylate and benzyl (meth)acrylate; can be done. Such (meth)acrylic acid esters can be used alone or in combination of two or more.

<<<(meth)acrylic acid hydroxy compound>>>
(Meth)acrylic acid hydroxy compounds include, for example, those having one or more hydroxyl groups in the molecule, which can be reaction sites with polyisocyanates such as diphenylmethane diisocyanate (C). Specifically, hydroxy acrylic compounds such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 3-hydroxy-2,2-dimethylpropyl acrylate, pentaerythritol triacrylate; 2-hydroxyethyl hydroxy methacrylate compounds such as methacrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl methacrylate, 3-hydroxy-2,2-dimethylpropyl methacrylate, and pentaerythritol trimethacrylate; These hydroxy acrylate compounds and/or hydroxy methacrylate compounds can be used alone or in combination of two or more.

<<<polymerization initiator>>>
The polymerization initiator can include thermal polymerization initiators and photopolymerization initiators, and is appropriately selected depending on the polymerization method.

Examples of thermal polymerization initiators include peroxydicarbonates such as di-2-ethylhexylperoxydicarbonate; t-butyl peroxybenzoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxyisopropyl carbonate, t - peroxyesters such as hexylperoxyisopropyl carbonate; di(t-butylperoxy)-2-methylcyclohexane, di(t-butylperoxy)3,3,5-trimethylcyclohexane and di(t-butylperoxy)cyclohexane peroxyketals; and the like.

Examples of photopolymerization initiators include acetophenone, methoxyacetophenone, 2,2-diethoxyacetophenone, p-dimethylaminoacetophenone, 2,2-dimethoxy-2-phenylacetophenone, α-hydroxy-α,α'-dimethylacetophenone. , 2-hydroxy-2-cyclohexylacetophenone, 2-methyl-1[4-(methylthio)phenyl]-2-monforinopropanone-1 and other acetophenones; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl Benzoin ethers such as butyl ether, benzophenone, 2-chlorobenzophenone, p,p'-dichlorobenzophenone, N,N'-tetramethyl-4,4'-diaminobenzophenone, 4-(2-hydroxyethoxy)phenyl(2- hydroxy-2-propyl)ketones; thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone; phosphine oxides, such as bisacylphosphine oxide and benzoylphosphine oxide; benzyl dimethyl ketal, etc. ketals; quinones such as camphane-2,3-dione and phenanthrenequinone; and the like.

<<Silicone Polyol>>
Examples of silicone polyols include vinyl group-containing silicone compounds obtained by polymerizing γ-methacryloxypropyltrimethoxysilane and the like, and α,ω-dihydroxypolydimethylsiloxane, α,ω having at least one terminal hydroxyl group in the molecule. - Polysiloxanes such as dihydroxypolydiphenylsiloxane.

<<castor oil-based polyol>>
Castor oil-based polyols include, for example, linear or branched polyester polyols obtained by reacting castor oil fatty acids with polyols. Dehydrated castor oil, partially dehydrated castor oil, and hydrogenated castor oil to which hydrogen is added can also be used.

<<fluorinated polyol>>
The fluorine-based polyol is, for example, a linear or branched polyol obtained by a copolymerization reaction of a fluorine-containing monomer and a monomer having a hydroxyl group as essential components. Here, the fluorine-containing monomer is preferably a fluoroolefin such as tetrafluoroethylene, chlorotrifluoroethylene, trichlorofluoroethylene, hexafluoropropylene, vinylidene fluoride, vinyl fluoride, trifluoromethyltrifluoroethylene. etc. Examples of monomers 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; vinyl hydroxyalkyl crotonates; hydroxyl group-containing vinyl carboxylates, such as; monomers having hydroxyl groups, such as allyl esters; and the like.

<<monomer polyol (F)>>
When the monomer polyol (F) and the polyol (E) are used together as the hydroxyl group-terminated curing agent (B), aggregation of hard segments composed of the monomer polyol (F) and diphenylmethane diisocyanate (C) occurs. The present inventors speculate that this aggregation facilitates microphase separation, which is advantageous due to low friction. When the monomer polyol (F) and the polyol (E) are used together as the hydroxyl terminal curing agent (B), the appearance of the obtained thermosetting polyurethane elastomer molding becomes more cloudy, and friction can be reduced. .

Examples of the monomer polyol (F) 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 etc. Among these, it is preferable to use ethylene glycol as the monomer polyol (F) from the viewpoint of easiness of clouding.

<<catalyst (H)>>
A catalyst (H) may be added to the hydroxyl group-terminated curing agent (B) as necessary. Although the catalyst (H) is not particularly limited, the urethanization catalyst for polyurethane (H1) is preferable from the viewpoint of improving mechanical properties and moldability.
Incidentally, if necessary, the polyurethane nurate catalyst (H2) and the polyurethane allophanat catalyst (H3) can be used together or singly.

<<<urethane catalyst for polyurethane (H1)>>>
The urethanization catalyst (H1) for polyurethane used in the urethanization reaction can be appropriately selected from conventionally known catalysts and used. metal-based catalysts, and the like.

Examples of amine catalysts include 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″-penta Methyldipropylenetriamine, N,N,N',N'-tetramethylhexamethylenediamine, bis(2-dimethylaminoethyl)ether, dimethylethanolamine, dimethylisopropanolamine, dimethylaminoethoxyethanol, N,N-dimethyl- N'-(2-hydroxyethyl)ethylenediamine, N,N-dimethyl-N'-(2-hydroxyethyl)propanediamine, bis(dimethylaminopropyl)amine, bis(dimethylaminopropyl)isopropanolamine and the like.

Examples of imidazole-based catalysts include 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethylaminopropylimidazole, N,N-dimethylhexanolamine, and 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.

Examples of diazacycloamine salt-based catalysts include 1,8-diazabicyclo(5,4,0)-undecene-7 or 1,5-diazahicyclo(4,3,0)-nonene-5, octylic acid, Examples include diazacycloamine salts composed of oleic acid, p-toluenesulfonic acid, formic acid, phenolic acid, orthophthalic acid, acetic acid, maleic acid, or boric acid.

Examples of metal-based catalysts include organic tins such as stannus diacetate, stannus dioctoate, stannus dioleate, stannus dilaurate, dibutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, and dioctyltin dilaurate. catalysts, nickel octylate, nickel naphthenate, cobalt octylate, cobalt naphthenate, bismuth octylate, bismuth naphthenate and the like.

In addition, these polyurethane urethanization catalysts (H1) can be used alone or in combination of two or more. The amount of the urethanization catalyst for polyurethane (H1) used is 0.001% by mass or more and 0.5% by mass with respect to the total mass of the isocyanate group-terminated urethane prepolymer (A) and the hydroxyl group-terminated curing agent (B). % or less, and more preferably 0.005% by mass or more and 0.10% by mass or less from the viewpoint of ease of reaction control.

<<<Polyurethane nurate catalyst (H2)>>>
As the nurating catalyst (H2) for polyurethane used in the nurating reaction, it can be appropriately selected from conventionally known catalysts and used. Examples include ammonium carbonate, hydroxyalkylammonium hydroxide, and alkali metal salts of carboxylic acids.

Tertiary amines include, for example, triethylamine, N-ethylpiperidine, N,N'-dimethylpiperazine, N-ethylmorpholine, Mannich bases of phenol compounds, and the like.

Examples of quaternary ammonium hydrogencarbonates include tetramethylammonium hydrogencarbonate, methyltriethylammonium hydrogencarbonate, ethyltrimethylammonium hydrogencarbonate, propyltrimethylammonium hydrogencarbonate, butyltrimethylammonium hydrogencarbonate, and pentyltrimethylammonium. Bicarbonate, hexyltrimethylammonium hydrogencarbonate, heptyltrimethylammonium hydrogencarbonate, octyltrimethylammonium hydrogencarbonate, nonyltrimethylammonium hydrogencarbonate, decyltrimethylammonium hydrogencarbonate, undecyltrimethylammonium hydrogencarbonate, dodecyltrimethylammonium Hydrogen carbonate, tridecyltrimethylammonium hydrogen carbonate, tetradecyltrimethylammonium hydrogen carbonate, heptadecyltrimethylammonium hydrogen carbonate, hexadecyltrimethylammonium hydrogen carbonate, heptadecyltrimethylammonium hydrogen carbonate, octadecyltrimethylammonium hydrogen carbonate , (2-hydroxypropyl)trimethylammonium hydrogencarbonate, hydroxyethyltrimethylammonium hydrogencarbonate, 1-methyl-1-azania-4-azabicyclo[2.2.2]octanium hydrogencarbonate, 1,1-dimethyl- 4-methylpiperidinium hydrogen carbonate and the like.

Examples of quaternary ammonium carbonates include tetramethylammonium carbonate, methyltriethylammonium carbonate, ethyltrimethylammonium carbonate, propyltrimethylammonium carbonate, butyltrimethylammonium carbonate, pentyltrimethylammonium carbonate, and hexyltrimethylammonium carbonate. carbonate, heptyltrimethylammonium carbonate, octyltrimethylammonium carbonate, nonyltrimethylammonium carbonate, decyltrimethylammonium carbonate, undecyltrimethylammonium carbonate, dodecyltrimethylammonium carbonate, tridecyltrimethylammonium carbonate, tetradecyltrimethyl ammonium carbonate, heptadecyltrimethylammonium carbonate, hexadecyltrimethylammonium carbonate, heptadecyltrimethylammonium carbonate, octadecyltrimethylammonium carbonate, (2-hydroxypropyl)trimethylammonium carbonate, hydroxyethyltrimethylammonium carbonate, 1 -methyl-1-azania-4-azabicyclo[2,2,2]octanium carbonate, 1,1-dimethyl-4-methylpiperidinium carbonate, and the like.

Hydroxyalkylammonium hydroxides include, for example, hydroxides such as trimethylhydroxypropylammonium, trimethylhydroxypropylammonium and triethylhydroxyethylammonium.

Examples of alkali metal salts of carboxylic acids include alkali metal salts of carboxylic acids such as acetic acid, propionic acid, butyric acid, caproic acid, capric acid, valeric acid, octylic acid, myristic acid and naphthenic acid. Alkali metals used for these include lithium, sodium, potassium, rubidium, cesium, francium, and the like.

Potassium salts and quaternary ammonium salts are preferred as the polyurethane nurating catalyst (H2).

In addition, these polyurethane nurating catalysts (H2) can be used alone or in combination of two or more. The amount of the nurating catalyst (H2) used is 0.001% by mass or more and 0.5% by mass or less with respect to the total mass of the isocyanate group-terminated urethane prepolymer (A) and the hydroxyl group-terminated curing agent (B). Among them, from the viewpoint of easiness of reaction control, the range of 0.005% by mass or more and 0.10% by mass or less is more preferable.

<<<Polyurethane allophanatization catalyst (H3)>>>
The polyurethane allophanatization catalyst (H3) used in the allophanatization reaction can be appropriately selected from conventionally known catalysts, and for example, metal salts of carboxylic acids and alkanolamines can be used.

Examples of the carboxylic acid constituting the metal salt of carboxylic acid include monocarboxylic acids and polycarboxylic acids.
Monocarboxylic acids include saturated aliphatic carboxylic acids such as acetic acid, propionic acid, butyric acid, caproic acid, octylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, and 2-ethylhexanoic acid; cyclohexanecarboxylic acid, cyclopentane saturated monocyclic carboxylic acids such as carboxylic acids; saturated multicyclic carboxylic acids such as bicyclo(4.4.0)decane-2-carboxylic acid; mixtures of the aforementioned carboxylic acids such as naphthenic acid; oleic acid, linoleic acid, linolene acids, unsaturated aliphatic carboxylic acids such as soybean oil fatty acids and tall oil fatty acids; araliphatic carboxylic acids such as diphenylacetic acid; aromatic carboxylic acids such as benzoic acid and toluic acid;
Polycarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, succinic acid, tartaric acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, curtaconic acid, azelaic acid, and 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, pyro Merritt acid and the like can be mentioned.

Examples of metals constituting metal salts of carboxylic acids 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, transition metals such as cobalt, nickel, copper, zinc, and zirconium;

Specific examples of alkanolamine include N,N,N,N'-trimethylaminoethylethanolamine and N,N-dimethylaminoethoxyethanol.

N,N,N,N'-trimethylaminoethylethanolamine and N,N-dimethylaminoethoxyethanol are preferred as the allophanatization catalyst (H3) for polyurethane.

These polyurethane allophanatization catalysts (H3) can be used alone or in combination of two or more. The amount of the allophanatization catalyst (H3) used is 0.001% by mass or more and 0.5% by mass or less with respect to the total mass of the isocyanate group-terminated urethane prepolymer (A) and the hydroxyl group-terminated curing agent (B). Among them, from the viewpoint of easiness of reaction control, the range of 0.005% by mass or more and 0.10% by mass or less is more preferable.

<Other ingredients>
The thermosetting polyurethane elastomer-forming composition according to this aspect may further contain additives such as antioxidants, antifoaming agents, and ultraviolet absorbers, if necessary.

<Polyol (D) Having Ether Unit, Polyol (E) Having Ester Unit>
The ratio of the weight W _D of the polyol (D) to the weight W _E of the polyol (E) (W _D /W _E ) in the total amount of the thermosetting polyurethane elastomer-forming composition is 20/80 or more and 90/10. is preferably 30/70 or more and 80/20 or less is particularly preferable. When the ratio (W _D /W _E ) is within the predetermined range, the immiscibility can be improved more efficiently, and the frictional force can be further reduced.

[Thermosetting polyurethane elastomer]
Thermosetting polyurethane elastomers include cured products of the thermosetting polyurethane elastomer-forming compositions described above.

<Method for Producing Cured Product (Thermosetting Polyurethane Elastomer, Molded Product) of Thermosetting Polyurethane Elastomer Forming Composition>
In this embodiment, using the thermosetting polyurethane elastomer-forming composition described above, a curing treatment (specifically, a treatment for accelerating curing by heating) is performed in a mold to urethanize, and A thermoset polyurethane elastomer molding with nurated, allophanatized linkages is produced.
In this case, the method for producing the thermosetting polyurethane elastomer molding according to one aspect of the present invention using the thermosetting polyurethane elastomer-forming composition according to one aspect of the present invention includes the following (1 ) to (4) are preferred.

(1): An isocyanate group-terminated prepolymer (A) and a hydroxyl group-terminated curing agent (B) are uniformly mixed to prepare a thermosetting polyurethane elastomer-forming composition. However, when the catalyst (H) is not included in the hydroxyl terminal curing agent (B) in advance, the catalyst (H) is added separately. If air bubbles are found due to entrainment of air, the bubbles are removed by vacuum defoaming or the like. For these, it is preferable to use a dedicated polyurethane casting machine.

(2): Immediately after mixing the forming composition into the preheated mold, the forming composition is poured into the mold (casting), and the forming composition is cured in the mold (specifically, by heating hardening reaction). In this case, the temperature of the mold is preferably in the range of 90° C. or higher and 150° C. or lower from the viewpoint that the urethanization reaction, nurate formation, and allophanate formation reactions can be easily and reliably carried out.

(3): After the forming composition is cured, the cured product (that is, thermosetting polyurethane elastomer, molded product) is removed from the mold (mold removal). In this embodiment, the time required from casting to demolding is not particularly limited, but from the viewpoint of the productivity of the thermosetting polyurethane elastomer, the amount of catalyst and the preheating temperature of the mold are adjusted. and preferably in the range of 1 minute or more and 180 minutes or less.

(4): After curing, the thermosetting polyurethane elastomer molding (industrial machinery part) is removed from the mold and then aged at room temperature for one week. Here, the room temperature is not particularly limited as long as it is a general work environment, but it means, for example, 20° C. or more and 25° C. or less.

The molar ratio (OH group/NCO group) between the OH group content of the hydroxyl group-terminated curing agent (B) and the NCO group content of the isocyanate group-terminated urethane prepolymer (A) at the time of casting is determined by the selected catalyst species. can be selected according to the desired physical properties.
For example, when the urethanization catalyst (H1) is used alone, the molar ratio (OH group/NCO group) is preferably 0.8 or more and 1.0 or less. If it is 0.8 or more and 1.0 or less, sufficient molecular elongation can be performed, and the occurrence of problems such as insufficient curing and deterioration of physical properties can be further suppressed.
When using the polyurethane nurate catalyst (H2) or the polyurethane allophanat catalyst (H3), the molar ratio (OH group/NCO group) is preferably 0.2 or more and 0.8 or less. In this case, a urethanization catalyst (H1) can also be used together. When it is 0.2 or more and 0.8 or less, the amount of cross-linking points can be made more appropriate. That is, since it is possible to suppress an excessive increase in nurate formation and allophanat formation due to excess isocyanate, it is possible to suppress a significant decrease in tensile properties due to an increase in cross-linking points. In addition, since it is possible to suppress an extremely decrease in cross-linking points due to nurate formation or allophanate formation, it is possible to suppress an increase in the amount of deformation due to stress caused by a decrease in initial modulus (M100), and to further increase the strength against hardness. .

[Thermosetting polyurethane elastomer]
A thermosetting polyurethane elastomer according to one aspect of the present invention is a cured product obtained by curing the above-described thermosetting polyurethane elastomer-forming composition.

[Industrial Machinery Parts, Manufacturing Method of Industrial Machinery Parts]
An industrial machine part according to one aspect of the present invention is a cured product obtained by curing the thermosetting polyurethane elastomer-forming composition described above, and has a JIS-A hardness of 70° or more and 98° or less. And the dynamic friction coefficient is 0.8 or less. The JIS-A hardness is preferably 70° or more and 95° or less. Also, the coefficient of static friction is preferably 0.8 or less.
Specific examples of industrial machine parts include rolls, rollers, conductive belts, wipers, squeegees, and the like. In particular, suitable examples include industrial machinery articles that require low friction or that become hot due to temperature rise during continuous operation and that require excellent mechanical strength and durability.

A method for manufacturing an industrial machine part according to one aspect of the present invention includes curing the above-described thermosetting polyurethane elastomer-forming composition at 90° C. or higher and 150° C. or lower to obtain a cured product.

One aspect of the present invention is to use a conventional urethane raw material without using a lubricant or reducing the content of the lubricant, but by taking a specific combination, low friction is achieved, and heat generation and fatigue are reduced. By being reduced, it is possible to provide a thermosetting polyurethane elastomer-forming composition that contributes to the formation of a thermosetting polyurethane elastomer having excellent durability. In another aspect of the present invention, the thermosetting polyurethane elastomer-forming composition has excellent heat resistance and durability by reducing heat generation and fatigue by reducing friction, It is possible to provide a thermosetting polyurethane elastomer with reduced frictional force, an industrial machine part, and a method for producing the same.

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these. In Examples and Comparative Examples, "%" means "% by mass".

[Examples 1 to 6, Comparative Examples 1 to 5]
Various isocyanates (C), reaction inhibitors (G), and antioxidants were added and stirred in a 5-liter stirring vessel filled with nitrogen according to the compounding ratios (mass) shown in Tables 1 and 2. Then, various polyols (D) were added and stirred while maintaining the temperature in the stirring vessel at 40 to 70°C. Subsequently, an antifoaming agent was added and the urethanization reaction was allowed to proceed for about 2 to 5 hours while maintaining the temperature in the stirring vessel at 70 to 90° C., thereby obtaining various isocyanate group-terminated urethane prepolymers (A).

In addition, according to each blending ratio (mass) shown in Tables 1 and 2, various polyols (E) or (D), various catalysts (H), and antifoaming agents were added in a 5 L stirring vessel filled with nitrogen. The mixture was charged and stirred, and the mixture was stirred for about 1 to 3 hours while maintaining the temperature in the stirring vessel at 40 to 70°C to obtain various hydroxyl group terminal curing agents (B).

The abbreviations of raw materials used in Tables 1 and 2 are as follows.
"Diphenylmethane diisocyanate (C)"
(1) Monomeric MDI; Millionate MT (manufactured by Tosoh Corporation), 4,4'-MDI, NCO content = 33.6%
(2) Polymeric MDI; Millionate MR-400 (manufactured by Tosoh Corporation), polynuclear MDI, etc., NCO content = 30.0%

"Ether unit-containing polyol (D)"
(3) 2f_PPG-4000; Sannics PP-4000 (manufactured by Sanyo Chemical Industries, Ltd.), polyoxypropylene glycol, number of functional groups = 2, hydroxyl value = 28.1 KOHmg/g
(4) 2f_PPG-3000; Sannics PP-3000 (manufactured by Sanyo Chemical Industries, Ltd.), polyoxypropylene glycol, number of functional groups = 2, hydroxyl value = 37.4 KOHmg/g
(5) 2f_PTMG-2000; PTMG-2000 (manufactured by Mitsubishi Chemical Corporation), polytetramethylene glycol, number of functional groups = 2, hydroxyl value = 56.1 KOHmg/g
(6) 2f_PTMG-1300; PTMG-1300 (manufactured by Mitsubishi Chemical Corporation), polytetramethylene glycol, number of functional groups = 2, hydroxyl value = 86.3 KOHmg/g
(7) 2f_PTMG-1000; PTMG-1000 (manufactured by Mitsubishi Chemical Corporation), polytetramethylene glycol, number of functional groups = 2, hydroxyl value = 112.2 KOHmg/g

"Ester unit-containing polyol (E)"
(8) 2f_PCL-4000; Plaxel 240 (manufactured by Daicel), polycaprolactone diol, bifunctional, hydroxyl value = 28.1 KOHmg/g
(9) 2f_PCL-3000; Plaxel 230 (manufactured by Daicel), polycaprolactone diol, number of functional groups = 2, hydroxyl value = 37.4 KOHmg/g
(10) 3f_PCL-550; Plaxel 305 (manufactured by Daicel), polycaprolactone triol, number of functional groups = 3, hydroxyl value = 306.1 KOHmg/g
(11) 3f_PCL-300; Plaxel 303 (manufactured by Daicel), polycaprolactone diol, number of functional groups = 2, hydroxyl value = 561.1 KOHmg/g
(12) 2f_PBA-2000; NIPPOLAN 4010 (manufactured by Tosoh Corporation), polybutylene adipate, number of functional groups = 2, hydroxyl value = 56.1 KOHmg/g
(13) 2f_PBA-1000; NIPPOLAN 4009 (manufactured by Tosoh Corporation), polybutylene adipate, number of functional groups = 2, hydroxyl value = 112.2 KOHmg/g

"Monomer polyol (F) having a molecular weight of 300 or less"
(14) EG; ethylene glycol (manufactured by Mitsubishi Chemical Corporation), hydroxyl value = 1,808 KOHmg/g
(15) 1,4-BG; 1,4-butanediol (manufactured by Mitsubishi Chemical Corporation), hydroxyl value = 1,245 KOHmg/g
(16) TMP; trimethylolpropane (Mitsubishi Gas Chemical Co., Ltd.), hydroxyl value = 1,247 KOHmg/g

"Catalyst (H)"
(17) TEDA-L33E; TOYOCAT TEDA-L33E (manufactured by Tosoh Corporation), a mixture of triethylenediamine and ethylene glycol (18) TMR; DABCO TMR (manufactured by Air Products and Chemicals, Inc.), a quaternary ammonium salt catalyst and ethylene glycol A mixture of (19) RX-5; TOYOCAT RX-5 (manufactured by Tosoh Corporation), trimethylaminoethylethanolamine

"Others/Additives"
(20) PS-236; Phospholan PS-236 (reaction inhibitor, manufactured by Akzo Nobel), mono-di(C10-12) pareth-5 phosphate (21) I-1010; Irganox 1010 (antioxidant, BASF) pentaerythritol tetrakis [3-(3′,5′-di-t-butyl-4′-hydroxyphenyl)propionate]
(22) BYK-052; Defoamer, manufactured by BYK Additives & Instruments

According to each curing temperature shown in Tables 3 and 4, casting molds for producing flat sheets having a thickness of 2 mm and 3 mm are kept warm in a constant temperature bath previously set to the curing temperature.
Next, according to each compounding ratio (mass) shown in Tables 3 and 4, an isocyanate group-terminated urethane prepolymer (A) preheated at 70 to 90 ° C. and a hydroxyl group-terminated curing agent preheated at 40 to 60 ° C. A thermosetting polyurethane elastomer-forming composition according to one aspect of the present invention was prepared by mixing (B) with a two-liquid mixing urethane casting machine.
Immediately, this composition was injected (casting mold) into a casting mold for forming a flat sheet having a thickness of 2 mm and 3 mm, which had been preheated to each curing temperature, and subjected to each curing condition (temperature x hours), the molded product was removed from the mold (demolding) after heat curing. After that, it was cured in a constant temperature room at 25° C. for 1 week to obtain a polyurethane elastomer molding (sheet) according to one aspect of the present invention.

Tables 5 and 6 show the characteristic values of the obtained molded sheets. Moreover, the characteristic evaluation method is as follows.

(1) JIS-A hardness; measured according to JIS K7312: 1996 "7. Hardness test".

(2) Tensile strength (TB), elongation (EB); measured according to JIS K7312: 1996 "5. Tensile test".

(3) Coefficient of static friction and coefficient of dynamic friction: Measured under the following conditions using a surface property measuring instrument TYPE: 38 (manufactured by Shinto Kagaku Co., Ltd.).
Test piece: Three rectangular (5 mm x 50 mm) dumbbell cutters (manufactured by Dumbbell Co., Ltd.) cut out from a 3 mm thick sheet, and the 3 mm thick surfaces cut out with a razor blade were used as test surfaces.
Measurement conditions; measurement jig = ball indenter (SUS, stainless steel), load = 100 g, table movement speed = 150 mm/min, table movement distance = 10 mm, number of reciprocations = 10 times, measurement atmosphere = temperature 23°C, humidity 50 RH%.
Test value: The average value of the static friction coefficient and the dynamic friction coefficient of 10 forward trips is taken as the value of one sample, and the average value of 3 samples is calculated.

According to Examples 1 to 6, with a specific isocyanate group-terminated urethane prepolymer and a specific hydroxyl group-terminated curing agent, existing urethane raw materials can be used without introducing a lubricant component with a risk of bleeding or blooming. It was possible to reduce the static friction coefficient and dynamic friction coefficient.

Comparative Example 1 is an example of using an isocyanate group-terminated urethane prepolymer (A) containing monomeric MDI (C) and polyoxypropylene glycol having an ether unit with a hydroxyl value of 28.1 KOHmg/g. is. Although the polyoxypropylene glycol has an ether unit, it has a hydroxyl value of less than 30 KOHmg/g. Therefore, the resulting isocyanate group-terminated urethane prepolymer (A) has a high kinematic viscosity of 2800 mm ² /s. rice field. The kinematic viscosity was measured at 75° C. using a Canon Fenske viscometer #500 (manufactured by Tokyo Glass Instruments Co., Ltd.).
Using this, a molded product was obtained by casting into a mold, but flowability was poor and a 2 mm thick sheet with a sufficient area could not be obtained. Therefore, measurement of tensile properties was stopped. Although the flowability of the 3 mm thick sheet was not sufficient, it was possible to cut it into a rectangle of 5 mm x 50 mm. As a result of confirming the coefficient of friction of the obtained test piece, both the coefficient of static friction and the coefficient of dynamic friction exceeded 0.8 and were not sufficient values.

Comparative Example 2 is an example of using an isocyanate group-terminated urethane prepolymer (A) containing monomeric MDI (C) and polytetramethylene glycol having an ether unit with a hydroxyl value of 112.2 KOHmg/g. be. Although the polytetramethylene glycol has an ether unit, since the hydroxyl value exceeds 90 KOHmg/g, the obtained thermosetting polyurethane elastomer-forming composition was transparent in appearance.
As a result of confirming the coefficient of friction of the obtained test piece, both the coefficient of static friction and the coefficient of dynamic friction exceeded 0.8 and were not sufficient values.

Comparative Example 3 contains polycaprolactone diol having an ester unit with a hydroxyl value of 28.1 KOHmg/g, 1,4-butanediol, which is a monomer polyol having a molecular weight of 300 or less, and trimethylolpropane. This is an example of using the agent (B). The polycaprolactone diol has an ester unit, but since the hydroxyl value is less than 30 KOHmg/g, the obtained hydroxyl value terminal curing agent (B) has poor compatibility and turbidity occurs, resulting in non-uniform storage stability. The quality was poor, and there was concern about the quality stability as an industrial machine part.
As a result of confirming the coefficient of friction of the obtained test piece, both the coefficient of static friction and the coefficient of dynamic friction exceeded 0.8 and were not sufficient values.

Comparative Example 4 uses a hydroxyl value terminal curing agent (B) containing polycaprolactone diol having an ester unit with a hydroxyl value of 561.1 KOHmg/g and 1,4-butanediol, which is a monomer polyol having a molecular weight of 300 or less. This is an example of using.
Although the polycaprolactone diol has an ester unit, it has a hydroxyl value of more than 310 KOHmg/g, so that the thermosetting polyurethane elastomer-forming composition obtained using these had a transparent appearance.
As a result of confirming the coefficient of friction of the obtained test piece, both the coefficient of static friction and the coefficient of dynamic friction exceeded 0.8 and were not sufficient values.

Comparative Example 5 is an isocyanate group-terminated urethane prepolymer (A) containing a monomeric MDI (C) and a polytetramethylene glycol (D) having an ether unit with a hydroxyl value of 56.1 KOHmg/g, and a hydroxyl group A hydroxyl terminal curing agent (B) containing polytetramethylene glycol having an ether unit with a molecular weight of 112.2 KOHmg/g, 1,4-butanediol, which is a monomer polyol having a molecular weight of 300 or less, and trimethylolpropane. This is an example of using.
The hydroxyl terminal curing agent (B) uses a polyol having an ether unit without using a polyol (E) having a hydroxyl value of 30 KOHmg/g or more and 310 KOHmg/g or less having an ester unit. The resulting thermosetting polyurethane elastomer-forming composition was transparent in appearance.
As a result of confirming the coefficient of friction of the obtained test piece, both the coefficient of static friction and the coefficient of dynamic friction exceeded 0.8 and were not sufficient values.

Claims (5)

an isocyanate group-terminated urethane prepolymer (A);
and a hydroxyl group terminal curing agent (B),
The isocyanate group-terminated urethane prepolymer (A) is
diphenylmethane diisocyanate (C); and
and a polyol (D) having an ether unit,
The hydroxyl value of the polyol (D) is 30 KOHmg/g or more and 90 KOHmg/g or less,
The hydroxyl group-terminated curing agent (B) contains a polyol (E) having an ester unit,
The hydroxyl value of the polyol (E) is 30 KOHmg/g or more and 310 KOHmg/g or less.
A thermosetting polyurethane elastomer-forming composition. The ratio (W D /W _E ) of the weight W _D of the polyol (D) to the weight W _E of the polyol (E) in the total amount of the thermosetting polyurethane elastomer- _forming composition is 20/80 or more and 90 10. The thermosetting polyurethane elastomer-forming composition according to claim 1, wherein the composition is 0/10 or less. 3. The thermosetting polyurethane elastomer-forming composition according to claim 1, wherein the hydroxyl terminal curing agent (B) further contains a monomer polyol (F) having a molecular weight of 300 or less. A thermosetting polyurethane elastomer comprising a cured product of the thermosetting polyurethane elastomer-forming composition according to any one of claims 1 to 3. A method for producing an industrial machine part, comprising curing the thermosetting polyurethane elastomer-forming composition according to any one of claims 1 to 3 at 90°C or higher and 150°C or lower to obtain a cured product.