Reactive adhesive, laminate, and insulator for motor

Abstract

To provide an adhesive which has good adhesion performance, and excellent durability against heat of an oil injection type motor, dissolution in an automatic transmission fluid and moisture in the automatic transmission fluid, a laminate using the adhesive, and an insulator for a motor.SOLUTION: A reactive adhesive contains acryl polyol (A) and polyisocyanate (B), wherein the acryl polyol (A) includes a constitutional unit derived from n-butyl methacrylate and a constitutional unit derived from n-butyl acrylate, based on the total amount of the total constitutional units of the acryl polyol (A), the constitutional unit derived from the n-butyl methacrylate is 50 mass% or more, and the constitutional unit derived from the n-butyl acrylate is 30 mass% or more, and the polyisocyanate (B) has at least one ring structure selected from an isocyanurate ring and an aromatic ring derived from aromatic polyisocyanate.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a reactive adhesive, which is suitable for use as an insulator for motors. [Background technology]

[0002] Motor generators that selectively function as electric motors and generators are installed in electric vehicles, hybrid vehicles, compressors, etc. The motor generators generate heat when the vehicle is accelerated or decelerated, and can reach high temperatures of over 100°C. The motor stator that constitutes the motor generator is generally composed of a core material and a winding, and insulating paper is used to insulate the core material from the winding or between different phase windings. Fixing devices for fixing the windings to prevent them from protruding, called wedges, interphase paper, and insulating caps, are also included in motor insulators, just like the insulating paper. In motor stators, which become hot due to heat generation, the insulating paper is also required to be heat resistant.

[0003] Conventionally, insulation materials for motors have been made of substrates such as polyester film, which has excellent electrical insulation and mechanical strength, aramid nonwoven fabric, which has improved properties such as heat resistance and chemical resistance, and polyphenylene sulfide film, or laminates made by laminating these substrates with an adhesive. However, in recent years, the operating temperature has risen further due to the miniaturization and high output of motors, and there is a demand for adhesives in the insulator to have improved durability in high-temperature environments. In addition, as the operating temperature rises, there is an increase in oil-cooled motors that cool the motor by pouring oil called automatic transmission fluid (ATF) over the motor, and there is a demand for adhesives in the insulator to have improved durability (heat and oil resistance) against automatic transmission fluid. In addition, automatic transmission fluid contains a small amount of moisture, so there is a demand for adhesives to have moisture and heat resistance, and various studies are being conducted.

[0004] In the above situation, for example, Patent Document 1 relates to an insulating paper for motors formed using a laminate sheet in which multiple sheet materials are laminated and bonded with a thermosetting adhesive, and describes that a thermosetting resin composition containing an epoxy resin component, a phenolic resin component, an acrylic resin component, and an imidazole-based curing agent component is used as the thermosetting adhesive, that the composition requires an epoxy resin component as an essential component, that bisphenol A-type epoxy resin is preferably used, and that the proportion of the epoxy resin component in the resin components contained in the thermosetting resin composition is 20 to 60 mass %.

[0005] Patent Document 2 also describes an acrylic adhesive composition used in the manufacture of a solar cell back surface protective sheet, which contains an acrylic polyol having a number average molecular weight of 10,000 to 100,000, a hydroxyl value of 1 to 100 mgKOH / g, and a glass transition temperature of more than -40°C and not more than 10°C, and a polyisocyanate, in which the equivalent ratio NCO / OH between the hydroxyl groups derived from the acrylic polyol and the isocyanate groups derived from the polyisocyanate is 0.1 to 3. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2008-178197 A [Patent Document 2] JP 2012-214703 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, the thermosetting resin composition described in Patent Document 1 contains a relatively large proportion of a bisphenol A-type epoxy resin component that contains bisphenol A, an environmental hormone, as an impurity, and cannot solve the safety issue. The acrylic adhesive described in Patent Document 2 does not combine butyl methacrylate and butyl acrylate, and there is no description or suggestion of the solution to the ATF durability problem by using such a combination. Therefore, an object of the present invention is to provide an adhesive that has good adhesive performance and further has excellent durability against the heat of an oil-cooled motor, against dissolution in automatic transmission fluid, and against the moisture in automatic transmission fluid, a laminate using the adhesive, and an insulator for a motor. [Means for solving the problem]

[0008] <1> A reactive adhesive containing an acrylic polyol (A) and a polyisocyanate (B), wherein the acrylic polyol (A) contains a structural unit derived from n-butyl methacrylate and a structural unit derived from n-butyl acrylate, the content of the structural units derived from n-butyl methacrylate being 50 mass% or more based on the total amount of all structural units of the acrylic polyol (A), and the content of the structural units derived from n-butyl acrylate being 30 mass% or more based on the total amount of all structural units of the acrylic polyol (A), and the polyisocyanate (B) having at least one ring structure selected from the group consisting of an isocyanurate ring and an aromatic ring derived from an aromatic polyisocyanate.

[0009] <2> The elastic modulus of a cured product obtained by curing the reactive adhesive at 250°C is 1.0 to 5.0 MPa. <1> The reactive adhesive according to claim 1.

[0010] <3> Contains 0.1 to 5 mass% of acetylacetone based on the mass of the reactive adhesive; <1> or <2> The reactive adhesive according to claim 1.

[0011] <4> A laminate in which a first substrate, an adhesive layer, and a second substrate are laminated in this order, the adhesive layer being: <1> ~ <3> A laminate which is a cured product of the reactive adhesive described in any one of claims 1 to 4.

[0012] <5> The laminate comprises a first substrate, a first adhesive layer, a second substrate, a second adhesive layer, and a third substrate laminated in this order, and the first adhesive layer and the second adhesive layer each independently comprise: <1> ~ <3> An insulator for a motor, which is a cured product of the reactive adhesive according to any one of claims 1 to 4.

[0013] <6> The first substrate and the third substrate are each independently at least one substrate selected from the group consisting of an aromatic polyamide fiber sheet and a polyphenylene sulfide film. <5> The motor insulation material according to claim 1 . Effect of the Invention

[0014] The present invention can provide an adhesive that has good adhesive performance, and further has excellent durability against the heat of an oil-cooled motor, against dissolution in automatic transmission fluid, and against the moisture in automatic transmission fluid, and that combines heat resistance and ATF resistance, as well as a laminate using the adhesive, and a motor insulator. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] <Reactive adhesive> The reactive adhesive of the present invention contains an acrylic polyol (A) and a polyisocyanate (B), the acrylic polyol (A) contains structural units derived from n-butyl methacrylate and structural units derived from n-butyl acrylate, the content of the structural units derived from n-butyl methacrylate is 50 mass% or more based on the total amount of all structural units of the acrylic polyol (A), and the content of the structural units derived from n-butyl acrylate is 30 mass% or more based on the total amount of all structural units of the acrylic polyol (A), and the polyisocyanate (B) has at least one ring structure selected from the group consisting of an isocyanurate ring and an aromatic ring derived from an aromatic polyisocyanate. The above-mentioned composition improves the wettability to the substrate and also increases the elastic modulus of the cured product at high temperatures, for example, at about 250°C, thereby providing excellent heat resistance and ATF resistance. In other words, the reactive adhesive of the present invention has a synergistic effect based on the following characteristics: the proportion of structural units derived from n-butyl methacrylate is 50% by mass or more, the proportion of structural units derived from n-butyl acrylate is 30% by mass or more, and the polyisocyanate (B) is a polyisocyanate having at least one ring structure selected from the group consisting of an isocyanurate ring and an aromatic ring derived from an aromatic polyisocyanate, and the effects of these characteristics work together to achieve excellent adhesive performance, heat resistance, and ATF resistance. The laminate of the present invention will now be described.

[0016] <Acrylic polyol (A)> The acrylic polyol (A) in the present invention has two or more hydroxyl groups in one molecule and contains a structural unit derived from n-butyl methacrylate and a structural unit derived from n-butyl acrylate. It is important that the content of the structural unit derived from n-butyl methacrylate is 50% by mass or more based on the total amount of all structural units of the acrylic polyol (A), and that the content of the structural unit derived from n-butyl acrylate is 30% by mass or more based on the total amount of all structural units of the acrylic polyol (A). The acrylic polyol (A) is preferably a copolymer of a hydroxyl group-containing mono(meth)acrylate and a hydroxyl group-free mono(meth)acrylate, including n-butyl methacrylate and n-butyl acrylate.

[0017] [Hydroxyl group-containing mono(meth)acrylate] The hydroxyl group-containing mono(meth)acrylate is a monomer that contains one (meth)acryloyl group and one or more hydroxyl groups in one molecule, and examples thereof include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, glycerol mono(meth)acrylate, 4-hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, allyl alcohol, (poly)ethylene glycol mono(meth)acrylate, ε-caprolactone-modified (meth)acrylate, and 2,3-dihydroxypropyl (meth)acrylate.

[0018] [Mono(meth)acrylates not containing hydroxyl groups] The acrylic polyol (A) in the present invention contains 50% by mass or more of structural units derived from n-butyl methacrylate and 30% by mass or more of structural units derived from n-butyl acrylate. It is presumed that the acrylic polyol (A) contains a high ratio of 80% by mass or more in total of n-butyl methacrylate and n-butyl acrylate, both of which have the same number of carbon atoms in the side chains bonded via ester bonds and the same solubility parameter δt value of 8.51, so that the entanglement of the side chains in the adhesive becomes uniform, a high elastic modulus can be maintained even in a high temperature range where molecules are easily mobile, and excellent resistance (heat resistance and ATF resistance) can be exhibited. In addition, since the acrylic polyol (A) in the present invention has a ratio of structural units derived from n-butyl methacrylate of 50% by mass or more, structural units derived from n-butyl methacrylate form a partial structure adjacent to each other in the copolymer. This partial structure allows the properties of a homopolymer of n-butyl methacrylate, which has a glass transition point of about 20°C in the room temperature range, to be expressed, improving the wettability of the adhesive to the substrate when applied. It is presumed that this allows good adhesive performance to be maintained even in high temperature ranges, and provides excellent heat resistance and ATF resistance.

[0019] The glass transition temperature (Tg) and solubility parameter (δt) of homopolymers of n-butyl acrylate and n-butyl methacrylate are as follows: n-butyl acrylate (Tg: -48°C, δt: 8.51 (cal / cm 3 ) 1 / 2 ), n-butyl methacrylate (Tg: 20°C, δt: 8.51 (cal / cm 3 ) 1 / 2 ).

[0020] In the present invention, the content of the structural unit derived from n-butyl methacrylate is preferably 65% ​​by mass or more from the viewpoint of forming a partial structure in which n-butyl methacrylate monomers are arranged in the acrylic polyol (A). Also, it is preferably 70% by mass or less. Also, the content of the structural unit derived from n-butyl acrylate is preferably 50% by mass or less, more preferably 45% by mass or less.

[0021] As the (meth)acrylate not containing a hydroxyl group other than n-butyl acrylate and n-butyl methacrylate, conventionally known radical polymerizable monomers can be appropriately selected and used. Examples of such monomers include alkyl (meth)acrylates such as methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, isobutyl acrylate, isobutyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, n-octyl acrylate, n-octyl methacrylate, lauryl acrylate, lauryl methacrylate, n-decyl acrylate, n-decyl methacrylate, stearyl acrylate, and stearyl methacrylate; (meth)acrylic acid, maleic acid, and maleic anhydride, and carboxyl group-containing (meth)acrylates and their anhydrides; and the above may be used in combination. The acrylic polyol (A) may be copolymerized with a vinyl monomer such as acrylonitrile or styrene.

[0022] In the present invention, the weight average molecular weight of the acrylic polyol (A) is preferably 10,000 or more, more preferably 30,000 or more, from the viewpoint of heat resistance and ATF resistance. Also, from the viewpoint of laminate strength, it is preferably 250,000 or less, more preferably 100,000 or less. The weight average molecular weight of the acrylic polyol (A) may be, for example, 10,000 to 250,000, or 30,000 to 100,000.

[0023] In the present invention, the weight average molecular weight is a value determined by gel permeation chromatography (GPC) and converted into polystyrene equivalent.

[0024] The hydroxyl value of the acrylic polyol (A) is determined by the content of the hydroxyl group-containing mono(meth)acrylate, and is preferably 50 mgKOH / g or less, more preferably 15 mgKOH / g or less, from the viewpoint of laminate strength and wet heat resistance. Also, it is preferably 1 mgKOH / g or more. The hydroxyl value of the acrylic polyol (A) may be, for example, 1 to 50 mgKOH / g, or 1 to 15 mgKOH / g.

[0025] In the present invention, the glass transition point (Tg) of the acrylic polyol (A) is preferably −20° C. or higher, more preferably −15° C. or higher, in terms of the balance between adhesive strength and durability such as heat resistance, moist heat resistance, heat resistance, and oil resistance, and is preferably 5° C. or lower, more preferably 0° C. or lower, and even more preferably −2° C. or lower.

[0026] In the present invention, the glass transition temperature (Tg) of the acrylic polyol (A) is a value calculated based on the following formula (1) (Fox formula). 1 / Tg=W1 / Tg1+W2 / Tg2+ +Wn / Tgn (Formula 1) The above formula (1) is a calculation formula when the acrylic polyol (A) is composed of n types of monomer components, namely, monomer 1, monomer 2, . . . , monomer n.

[0027] In formula (1), Tg is the Tg (unit: K) of the acrylic polyol (A), Tgi (i = 1, 2, ... n) is the Tg (unit: K) when the radical polymerizable monomer i forms a homopolymer, and Wi (i = 1, 2, ... n) is the mass fraction of the radical polymerizable monomer i in the total monomer components. The Tg of the homopolymers of the main monomers used in the calculation are shown below.

[0028] 2-Hydroxyethyl acrylate: -15℃ 2-Hydroxyethyl methacrylate: 55℃ 2-Hydroxypropyl methacrylate: 26℃ 4-Hydroxybutyl acrylate: -60℃ Methyl acrylate: 6℃ Methyl methacrylate: 105℃ Ethyl acrylate: -24℃ Ethyl methacrylate: 65℃ n-Butyl acrylate: -48℃ n-Butyl methacrylate: 20℃ Isobutyl acrylate: -40℃ Isobutyl methacrylate: 48℃ tert-Butyl acrylate: 14℃ tert-Butyl methacrylate: 107℃ 2-Ethylhexyl acrylate: -50℃ 2-Ethylhexyl methacrylate: -10℃ n-Octyl acrylate: -65℃ n-Octyl methacrylate: -20℃ Lauryl acrylate: -3℃ Lauryl methacrylate: -65℃ n-Decyl acrylate: -65℃ n-Decyl acrylate: -80℃ n-Decyl methacrylate: -70℃ Stearyl acrylate: -100℃ Stearyl methacrylate: 38℃

[0029] For monomers other than those mentioned above, use the homopolymer Tg of the monomers listed in "Polymer Data Handbook - Basic Edition - First published in 1986."

[0030] <Polyisocyanate (B)> It is important that the polyisocyanate (B) in the present invention has at least one ring structure selected from the group consisting of an isocyanurate ring and an aromatic ring derived from an aromatic polyisocyanate. By using such a polyisocyanate, the elastic modulus of the cured coating film after crosslinking in the high temperature range is improved, and therefore excellent heat resistance, heat resistance, oil resistance, and moist heat resistance can be achieved.

[0031] [Polyisocyanate having an isocyanurate ring] Examples of polyisocyanates having an isocyanurate ring include nurates derived from diisocyanates. For example, nurates of alicyclic diisocyanates such as isophorone diisocyanate and methyl-2,6-cyclohexane diisocyanate; nurates of aliphatic diisocyanates such as hexamethylene diisocyanate and pentamethylene diisocyanate; and nurates of aromatic diisocyanates such as 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), xylylene diisocyanate (XDI), diphenylmethane diisocyanate (MDI), and 1,5-naphthalene diisocyanate can be used.

[0032] [Polyisocyanates having aromatic rings derived from aromatic polyisocyanates] Examples of polyisocyanates having an aromatic ring derived from an aromatic polyisocyanate include compounds derived from aromatic diisocyanates. Examples of usable polyisocyanates include trimethylolpropane adducts of aromatic diisocyanates, biuret types, prepolymers having an isocyanate residue (low polymers obtained from diisocyanates and polyols), uretdione types having an isocyanate residue, allophanate types, and complexes thereof. Examples of the aromatic diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, and 1,5-naphthalene diisocyanate. These polyisocyanates (B) may be used alone or in combination of two or more kinds.

[0033] In the present invention, from the viewpoint of improving the elastic modulus in the high temperature range, the polyisocyanate (B) is preferably a nurate of an alicyclic diisocyanate, a nurate of an aliphatic diisocyanate, or a trimethylolpropane adduct of an aromatic diisocyanate, and more preferably a nurate of an aliphatic diisocyanate.

[0034] <Storage modulus (Er) of cured product at 250℃> The reactive adhesive of the present invention preferably has a storage modulus value of 1.0 to 5.0 MPa at 250°C of the cured product obtained by curing the adhesive. By having a storage modulus value in the above range, the adhesive can maintain its cohesive force even in high temperature ranges and exhibit excellent durability in high temperature ranges. In detail, when the storage modulus of the cured product at 250°C is 1.0 MPa or more, durability against heat, moist heat, and hot oil is improved. When the storage modulus of the cured product at 250°C is 5.0 MPa or less, adhesion to substrates under conditions of heat, moist heat, and hot oil is improved. The storage modulus value varies depending on the types and amounts of polyol (A), polyisocyanate (B), additives, etc., and can be adjusted to bring the storage modulus value at 250°C into the above range by adjusting these conditions. From the viewpoint of achieving both adhesive strength and durability at high temperatures, the storage modulus of the cured product at 250° C. is more preferably 1.2 MPa or more, more preferably 4.5 MPa or less, and even more preferably 4.0 MPa or less. The storage modulus of the cured product at 250° C. may be, for example, 1.0 to 4.5 MPa, 1.0 to 4.0 MPa, 1.2 to 5.0 MPa, 1.2 to 4.5 MPa, or 1.2 to 4.0 MPa.

[0035] The storage modulus can be determined by the following method based on JIS K 7244. The reactive adhesive is spread thinly onto a non-corona treated CPP film to a thickness of 10-20 μm using an applicator, and left to stand in an 80°C environment for 2 weeks to cure the adhesive. The laminate is then cut into a length of 20 mm and a width of 5 mm, and the CPP film is peeled off to obtain a cured product with a length of 20 mm, a width of 5 mm, and a thickness of 10-20 μm. The cured product is measured using a dynamic viscoelasticity measuring device (IT Measurement and Control Co., Ltd.'s "DVA-200") at a temperature of -30°C to 300°C, a frequency of 10 Hz, and a temperature rise rate of 10°C / min to determine the viscosity.

[0036] <Silane coupling agent> From the viewpoint of improving the adhesive strength to the substrate, the reactive adhesive of the present invention preferably contains a silane coupling agent. Examples of the silane coupling agent include, but are not limited to, vinyl silanes such as vinyltris(β-methoxyethoxy)silane, vinylethoxysilane, and vinyltrimethoxysilane; (meth)acryloxysilanes such as γ-(meth)acryloxypropyltrimethoxysilane, γ-(meth)acryloxypropyltriethoxysilane, and γ-(meth)acryloxypropyldimethoxymethylsilane; β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, β-(3,4-epoxycyclohexyl)methyltrimethoxysilane, β-(3,4-epoxycyclohexyl)ethyltriethoxysilane, and β-(3,4-epoxycyclohexyl)methyltriethoxysilane. Examples of the epoxy silanes include γ-glycidoxypropyl trimethoxysilane, γ-glycidoxypropyl triethoxysilane, etc.; amino silanes such as N-β(aminoethyl) γ-aminopropyl trimethoxysilane, N-β(aminoethyl) γ-aminopropyl triethoxysilane, N-β(aminoethyl) γ-aminopropyl methyl diethoxysilane, γ-aminopropyl triethoxysilane, γ-aminopropyl trimethoxysilane, N-phenyl-γ-aminopropyl trimethoxysilane, N-phenyl-γ-aminopropyl triethoxysilane, etc.; thio silanes such as γ-mercaptopropyl trimethoxysilane, γ-mercaptopropyl triethoxysilane, etc. These may be used alone or in combination of two or more.

[0037] The amount of the silane coupling agent to be added is preferably 0.1 to 5 mass %, more preferably 1 to 3 mass %, based on 100 mass % of the acrylic polyol (A) from the viewpoint of adhesive strength to a substrate.

[0038] <Phosphate compounds> To improve adhesion to substrates, the reactive adhesive of the present invention may contain added phosphoric acid compounds such as phosphoric acid, metaphosphoric acid, pyrophosphoric acid, phosphorous acid, and esters thereof.

[0039] <Epoxy resin> The reactive adhesive of the present invention preferably does not contain a bisphenol A type epoxy resin, but may contain an epoxy resin within a range that does not impair the effects of the present invention. The acrylic polyol (A) of the present invention may further contain an epoxy resin in order to improve durability under moist heat. The urethane cured product of the acrylic polyol (A) of the present invention may generate hydroxyl groups and amino groups by hydrolysis during moist heat resistance, but by containing an epoxy resin, the hydroxyl groups and amino groups react with the epoxy resin, and the moist heat resistance and durability can be further improved.

[0040] Examples of epoxy resins include bisphenol F type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins, polyglycerol polyglycidyl ether, 1,6-hexanediol diglycidyl ether, bisphenol F diglycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and polypropylene glycol diglycidyl ether. These epoxy resins may be used alone or in combination of two or more.

[0041] From the viewpoints of adhesiveness and durability, the epoxy resin preferably has a weight average molecular weight of 400 to 3000. When the epoxy resin is contained, the blending amount of the epoxy resin is preferably 1 to 30 mass % based on the solid content mass of the acrylic polyol (A) from the viewpoints of adhesiveness and durability.

[0042] <Reaction accelerator> The reactive adhesive of the present invention can be blended with known additives for adhesives without limitation within the scope of the present invention. For example, a reaction accelerator can be used, such as a tertiary amine catalyst such as triethylamine or dimethylaniline; or a metal catalyst such as tin, zinc, bismuth, zirconium, or titanium. Specific examples of the catalyst include metal catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, dibutyltin dimaleate, zirconium acetate, zirconium benzoate, zirconium naphthenate, dibutyltitanium dichloride, tetrabutyltitanate, tetrabutoxytitanate, tetraethyltitanate, tetraisopropyltitanate, zinc acetate, zinc oxalate, zinc naphthenate, zinc 2-ethylhexanoate, butoxytitanium trichloride, iron octylate, cobalt octylate, and zinc naphthenate; tertiary amines such as 1,8-diaza-bicyclo(5,4,0)undecene-7, 1,5-diazabicyclo(4,3,0)nonene-5, 6-dibutylamino-1,8-diazabicyclo(5,4,0)undecene-7, triethylamine, and triethylenediamine; and reactive tertiary amines such as triethanolamine. The reaction accelerators can be used alone or in combination of two or more.

[0043] <Acetylacetone> When the reactive adhesive of the present invention contains a reaction accelerator, the pot life may be shortened, but it is preferable to use acetylacetone in combination in order to improve the pot life of the adhesive. Also, when the reactive adhesive contains a reaction accelerator, hydrolysis may be accelerated, but by using acetylacetone in combination, hydrolysis can be suppressed and the wet heat resistance, heat resistance, and heat and oil resistance can be improved. The amount of acetylacetone blended, based on the mass of the reactive adhesive, is preferably 0.1 mass % or more from the viewpoint of improving pot life, and is preferably 7 mass % or less from the viewpoints of moist heat resistance, 150°C heat resistance, and ATF resistance, more preferably 5 mass % or less from the viewpoint of 150°C heat resistance, and is more preferably 3 mass % or less from the viewpoints of moist heat resistance and ATF resistance. The blending amount of acetylacetone may be, for example, 0.1 to 7 mass %, 0.1 to 5 mass %, or 0.1 to 3 mass %, based on the mass of the reactive adhesive.

[0044] <Leveling agents, defoamers> The reactive adhesive of the present invention may contain a known leveling agent or defoaming agent for the purpose of improving the appearance of the laminate. Examples of the leveling agent and defoaming agent include polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane, polyester-modified hydroxyl-containing polydimethylsiloxane, polyetherester-modified hydroxyl-containing polydimethylsiloxane, acrylic copolymer, methacrylic copolymer, polyether-modified polymethylalkylsiloxane, acrylic acid alkyl ester copolymer, methacrylic acid alkyl ester copolymer, lecithin, silicone resin, silicone solution, copolymer of alkyl vinyl ether, acrylic acid alkyl ester, and methacrylic acid alkyl ester, or mixtures thereof. When a leveling agent or defoaming agent is added, one type of compound may be used independently, or two or more types of compounds may be used in any combination.

[0045] <Other additives> In addition, known additives used in the present invention can include known phosphorus-based or phenol-based antioxidants, ultraviolet stabilizers, and metal deactivators for the purpose of further suppressing yellowing of the adhesive over time due to heat. These may be used alone or in any combination of two or more. The phosphorus-based or phenol-based antioxidants, ultraviolet stabilizers, and metal deactivators used in the present invention are preferably in the range of 0.05 to 5 mass% relative to 100 mass% of the solid content of the acrylic polyol (A), more preferably 0.1 to 1 mass%. When the amount added is 0.05 mass or more, a yellowing suppression effect is obtained, and when it is kept to 5 mass% or less, it is possible to achieve compatibility with adhesive strength.

[0046] The reactive adhesive of the present invention may contain known additives within the scope of the present invention, such as inorganic fillers such as silica, alumina, mica, talc, aluminum flakes, and glass flakes, layered inorganic compounds, stabilizers (UV absorbers, hydrolysis inhibitors, etc.), rust inhibitors, thickeners, plasticizers, antistatic agents, lubricants, antiblocking agents, colorants, fillers, crystal nucleating agents, and catalysts for adjusting the curing reaction.

[0047] <Organic solvent> The reactive adhesive of the present invention may contain an organic solvent. Examples of such organic solvents include esters such as ethyl acetate, butyl acetate, and cellosolve acetate; ketones such as acetone, methyl ethyl ketone, isobutyl ketone, methyl isobutyl ketone, and cyclohexanone; ethers such as tetrahydrofuran and dioxane; aromatic hydrocarbons such as toluene and xylene; halogenated hydrocarbons such as methylene chloride and ethylene chloride; dimethyl sulfoxide and dimethyl sulfamide. The organic solvent may be used alone or in combination of two or more. The reactive adhesive of the present invention preferably has a non-volatile content (solid content) in the range of 10 to 50 mass %, and the solid content can be adjusted using an organic solvent such as those exemplified above.

[0048] The reactive adhesive of the present invention may be a two-liquid mixed type in which a base agent containing a polyol (A) and a curing agent containing a polyisocyanate (B) are mixed at the time of use, or a one-liquid type in which the polyol (A) and the polyisocyanate (B) are mixed in advance. In addition, the acrylic polyol (A) and the polyisocyanate (B) may each be independently used in combination of two or more kinds, or a polyol or polyisocyanate other than (A) and (B) may be used in combination. When the reactive adhesive is a two-liquid mixture type, the base agent and the curing agent may each independently contain an organic solvent, an additive, etc., in addition to the acrylic polyol (A) or the polyisocyanate (B). From the viewpoint of suppressing curing inhibition, it is preferable to blend the silane coupling agent and acetylacetone in the base agent containing the polyol (A).

[0049] <Laminate> The laminate of the present invention is formed by sequentially laminating a first substrate, an adhesive layer, and a second substrate, and the adhesive layer is a cured product of the reactive adhesive described above. That is, the first substrate and the second substrate are laminated via an adhesive layer formed from the reactive adhesive described above, and can be produced, for example, by applying and drying the reactive adhesive on the first substrate, laminating the second substrate, and then curing the adhesive by aging. The adhesive can be applied and laminated by known methods such as a comma coater, dry laminator, roll knife coater, die coater, roll coater, bar coater, gravure roll coater, reverse roll coater, blade coater, gravure coater, microgravure coater, etc. The aging temperature is preferably from room temperature to less than 120°C, and the coating amount of the adhesive after drying is preferably 1 to 30 g / m 2 That's about it. The laminate of the present invention may further have another substrate laminated thereon, and in that case, the reactive adhesive of the present invention may be used.

[0050] <Motor insulation applications> The laminate of the present invention has excellent heat resistance, moist heat resistance, and ATF resistance, and can be used as an insulating material for a motor. For example, the insulating material for a motor may have a structure in which a first substrate, a first adhesive layer, a second substrate, a second adhesive layer, and a third substrate are laminated in this order, and the first adhesive layer and the second adhesive layer may each independently be a cured product of the reactive adhesive described above. The method for producing the motor insulator is not particularly limited, and it can be produced, for example, by the following method. First, the adhesive of the present invention is applied and dried on a first substrate to form a first adhesive layer, and then a second substrate is laminated so as to be in contact with the first adhesive layer to produce an intermediate laminate. Next, the reactive adhesive of the present invention is applied and dried on the intermediate laminate to form a second adhesive layer. Next, a third substrate is laminated so as to be in contact with the second adhesive layer on the intermediate laminate, and the adhesive is then cured by aging to produce a laminate (motor insulator).

[0051] Examples of the substrate in the motor insulation material as described above include a sheet made of aromatic polyamide fiber, a polyphenylene sulfide film, a polyimide film, a polyethylene naphthalate film, and a polyethylene terephthalate film. Among them, the substrates (first substrate and third substrate) arranged on the outer layer side are preferably substrates having excellent heat resistance. As such a substrate having excellent heat resistance, at least one selected from the group consisting of a sheet made of aromatic polyamide fiber and a polyphenylene sulfide film is preferably used. The second substrate is preferably at least one selected from the group consisting of a polyphenylene sulfide film, a polyimide film, a polyethylene naphthalate film, and a polyethylene terephthalate film. EXAMPLES

[0052] The present invention will be described in more detail below with reference to examples and comparative examples. In the examples and comparative examples, "parts" and "%" mean "parts by mass" and "% by mass" unless otherwise specified.

[0053] <Weight average molecular weight> The weight average molecular weight was measured using a Showdex (manufactured by Showa Denko K.K.) and columns: KF-805L, KF-803L, and KF-802 (manufactured by Showa Denko K.K.), with the column temperature at 40°C, THF as eluent, a flow rate of 0.2 ml / min, detection by RI, and a sample concentration of 0.02 mass%, and the value was calculated in terms of standard polystyrene.

[0054] <Storage modulus of cured product at 250℃> The storage modulus was determined according to JIS K 7244 by the following method. First, the reactive adhesive was thinly spread on a non-corona treated CPP film to a thickness of 10 to 20 μm using an applicator, and the adhesive was cured by leaving it in an 80°C environment for 2 weeks to produce a laminate. Next, the laminate was cut into a length of 20 mm and a width of 5 mm, and the CPP film was peeled off to obtain a cured product with a length of 20 mm, a width of 5 mm, and a thickness of 10 to 20 μm. The obtained cured product was measured and determined using a dynamic viscoelasticity measuring device (IT Measurement and Control Co., Ltd. "DVA-200") under the conditions of a measurement temperature starting from -30°C to 300°C, a frequency of 10 Hz, and a temperature rise rate of 10°C / min.

[0055] <Production of Acrylic Polyol (A)> (Synthesis Example 1) A four-neck flask equipped with a condenser, a nitrogen inlet tube, a dropping funnel, and a thermometer was charged with 100 parts of ethyl acetate and heated to 80°C. Next, a monomer liquid premixed with 18.2 parts of ethyl acrylate, 30.0 parts of n-butyl acrylate, 50.0 parts of n-butyl methacrylate, 1.8 parts of 2-hydroxyethyl methacrylate, and 1.0 parts of azobisisobutylnitrile was dropped from the dropping funnel over 2 hours. After that, the reaction was allowed to proceed for 1 hour, and then 0.1 parts of azobisisobutylnitrile was added and reacted for 1 hour until the monomer conversion rate reached 98% or more, and then the mixture was cooled. As additives, 1.0 part of acetylacetone, 0.45 parts of a glycidyl group-containing silane coupling agent ("KBM-403" manufactured by Shin-Etsu Chemical Co., Ltd.), and 0.01 parts of dioctyltin dilaurate ("Neostan U-810" manufactured by Nitto Kasei Co., Ltd.) were mixed, and the solid content was further adjusted to 50% with ethyl acetate to obtain an acrylic polyol (A1) solution.

[0056] (Synthesis Examples 2 to 22, Comparative Synthesis Examples 1 to 11) Acrylic polyol solutions (A2 to A22, S1 to S11) of Synthesis Examples 2 to 22 and Comparative Synthesis Examples 1 to 11 were obtained in the same manner as in Synthesis Example 1, except that the types and amounts of monomers used in the synthesis and the amount of acetylacetone were changed to those shown in Table 1.

[0057] [Table 1]

[0058] The abbreviations in Table 1 are as follows: EA: Ethyl acrylate BA: n-butyl acrylate EMA: Ethyl methacrylate BMA: n-Butyl methacrylate 2HEMA: 2-hydroxyethyl methacrylate

[0059] <Production of reactive adhesives> [Examples 1 to 30, Comparative Examples 1 to 15] The acrylic polyol solution and the polyisocyanate were mixed so that the solid content of the polyisocyanate relative to the solid content of the acrylic polyol solution was the curing agent blending ratio shown in Table 2, and then the solid content was adjusted to 30% with ethyl acetate to obtain a reactive adhesive.

[0060] <Evaluation of reactive adhesives> The reactive adhesive thus obtained was subjected to the following evaluations, and the results are shown in Table 2.

[0061] (Pot life) The solution viscosity of the resulting reactive adhesive at 25°C was measured immediately after mixing using a Brookfield viscometer. The reactive adhesive was then stored in an atmosphere at 25°C for 24 hours, and the solution viscosity at 25°C was then measured in the same manner using a Brookfield viscometer. The amount of change in viscosity due to storage at 25°C for 24 hours was determined and evaluated according to the following criteria. <Evaluation criteria> ◎ Excellent for practical use: Viscosity change is less than 100 mPa s ○ Practical range: Viscosity change is 100 mPa s or more but less than 200 mPa s △ Practical lower limit: Viscosity change is 200 mPa s or more but less than 400 mPa s × Not practical: Viscosity change is 400 mPa s or more

[0062] <Manufacture of laminates (insulators for motors)> The obtained reactive adhesive was applied to a polyphenylene sulfide film (Toray Industries, Torelina, thickness 50 μm) at a dry coating amount of 7 to 8 g / m 2 After the solvent was dried, the laminate was laminated with a polyester film (Toray Industries, Lumirror X-10S, thickness 50 μm) to obtain an intermediate laminate. Next, the reactive adhesive used above was applied to the polyester film side of the obtained intermediate laminate in a dry coating amount of 7 to 8 g / m. 2 After the solvent was dried, the resulting film was laminated with a polyphenylene sulfide film (Toray Industries, Inc., Torelina, thickness 50 μm) and aged at 60° C. for 6 days to obtain a laminate.

[0063] <Evaluation of laminates (insulation for motors)> The obtained laminate was subjected to the following evaluations, and the results are shown in Table 2.

[0064] (Laminate strength) The laminates were each cut into pieces measuring 200 mm x 15 mm, and a T-peel test was performed using a tensile tester to measure the peel strength (N / 15 mm width) between the polyphenylene sulfide film and the polyester film. The measurement was performed in an environment of 20°C and 65% RH at a loading speed of 300 mm / min, and the average value of three test pieces was used to evaluate according to the following criteria. ◎ Excellent for practical use: 3N / 15mm or more ○ Practical range: 2N / 15mm or more, less than 3N / 15mm △ Practical lower limit: 1N / 15mm or more, less than 2N / 15mm × Not practical: Less than 1N / 15mm

[0065] (Moisture and heat resistance) The laminates were each cut into pieces measuring 200 mm x 15 mm, and left to stand for 3000 hours in an environment of 85°C and 85% humidity. A T-peel test was then performed using a tensile tester to measure the peel strength (N / 15 mm width) between the polyphenylene sulfide film and the polyester film. The measurements were performed in an environment of 20°C and 65% RH, with a loading speed of 300 mm / min, and the average value of three test pieces was used to evaluate the results according to the following criteria. ◎ Excellent for practical use: 3N / 15mm or more ○ Practical range: 2N / 15mm or more, less than 3N / 15mm △ Practical lower limit: 1N / 15mm or more, less than 2N / 15mm × Not practical: Less than 1N / 15mm

[0066] (Heat resistance) The laminates were each cut into pieces measuring 200 mm x 15 mm, and left to stand in an environment at 180°C for 250 hours. Then, a T-peel test was performed using a tensile tester to measure the peel strength (N / 15 mm width) between the polyphenylene sulfide film and the polyester film. The measurement was performed in an environment of 20°C and 65% RH, with a loading speed of 300 mm / min, and the average value of three test pieces was used to evaluate according to the following criteria. ◎ Excellent for practical use: 3N / 15mm or more ○ Practical range: 2N / 15mm or more, less than 3N / 15mm △ Practical lower limit: 1N / 15mm or more, less than 2N / 15mm × Not practical: Less than 1N / 15mm

[0067] (ATF resistance (heat and oil resistance)) The laminates were cut into pieces measuring 200mm x 15mm each, and immersed in a heat-resistant, pressure-resistant, and chemical-resistant container filled with Nissan genuine autofluid (Matic Fluid S) so that the entire sample was immersed in the autofluid. 0.5% by mass of water was added relative to the amount of autofluid, and the sealed container was left to stand at 150°C for 600 hours. A T-type peel test was then performed using a tensile tester to measure the peel strength (N / 15mm width) between the polyphenylene sulfide film and the polyester film. The measurement was performed in an environment of 20°C and 65% RH, with a loading speed of 300mm / min, and the average value of three test pieces was used to evaluate the results according to the following criteria. ◎ Excellent for practical use: 3N / 15mm or more ○ Practical range: 2N / 15mm or more, less than 3N / 15mm △ Practical lower limit: 1N / 15mm or more, less than 2N / 15mm × Not practical: Less than 1N / 15mm

[0068] [Table 2]

[0069] The abbreviations in Table 2 are as follows: HDI Nurate: BASF's "Basonate HI-100", hexamethylene diisocyanate nurate IPDI Nurate: Evonik's "VESTANAT T 1890 / 100", nurate form of isophorone diisocyanate TDI-TMP: Tosoh Corporation's "Coronate L", a trimethylolpropane adduct of tolylene diisocyanate HDI-TMP: Tosoh Corporation's "Coronate HL", a trimethylolpropane adduct of hexamethylene diisocyanate HDI allophanate: Tosoh Corporation's "Coronate 2793", an allophanate derivative of hexamethylene diisocyanate

[0070] From the results in Table 2, the reactive adhesive of the present invention, which contains an acrylic polyol using BMA and BA in a specified ratio as raw materials, and a polyisocyanate having a specific ring structure, exhibited a good elastic modulus at 250°C and an excellent balance between adhesive strength and durability at high temperatures. As a result, not only was the adhesive performance excellent, but it also exhibited durability against motor heat, dissolution in automatic transmission fluid, and moisture in automatic transmission fluid, and was excellent in moist heat resistance, 150°C heat resistance, and heat and oil resistance. In particular, when the storage modulus of the cured product at 250° C. was 1.0 to 5.0 MPa, both adhesive strength and durability in high temperature ranges were excellent (Examples 2, 25 to 27). Furthermore, when the blending amount of acetylacetone was 0.1 to 7 mass % based on the mass of the reactive adhesive, excellent moist heat resistance, 150° C. heat resistance, and ATF resistance were exhibited.

[0071] On the other hand, all of the comparative examples were poor in ATF resistance, and did not achieve both 150° C. heat resistance and ATF resistance.

Claims

1. A reactive adhesive comprising an acrylic polyol (A) and a polyisocyanate (B), The acrylic polyol (A) contains a structural unit derived from n-butyl methacrylate and a structural unit derived from n-butyl acrylate, the content of the structural units derived from the n-butyl methacrylate is 50 mass% or more based on the total amount of all structural units of the acrylic polyol (A), the content of the structural units derived from the n-butyl acrylate is 30 mass% or more based on the total amount of all structural units of the acrylic polyol (A), The polyisocyanate (B) has at least one ring structure selected from the group consisting of an isocyanurate ring and an aromatic ring derived from an aromatic polyisocyanate. Reactive adhesive.

2. The reactive adhesive according to claim 1, wherein the cured product of the reactive adhesive has an elastic modulus of 1.0 to 5.0 MPa at 250°C.

3. 2. The reactive adhesive of claim 1, comprising 0.1 to 5% by weight of acetylacetone, based on the weight of the reactive adhesive.

4. A laminate in which a first substrate, an adhesive layer, and a second substrate are laminated in that order, the adhesive layer being a cured product of the reactive adhesive according to claim 1.

5. 13. An insulator for a motor comprising a laminate in which a first substrate, a first adhesive layer, a second substrate, a second adhesive layer, and a third substrate are laminated in that order, and the first adhesive layer and the second adhesive layer are each independently a cured product of the reactive adhesive described in claim 1.

6. 6. The motor insulation material according to claim 5, wherein the first substrate and the third substrate are each independently at least one substrate selected from the group consisting of a sheet made of aromatic polyamide fiber and a polyphenylene sulfide film.

Images