Isocyanate composition, two-component urethane resin-forming composition, composition for adhesives, and adhesive

Abstract

To provide an isocyanate composition, a two-pack urethane resin formative composition, a composition for an adhesive, and an adhesive which can exhibit an excellent adhesive strength at room temperature and high temperature.SOLUTION: An isocyanate composition contains diphenylmethane diisocyanate (a1), and an isocyanurate-modified body (a2), in which the isocyanurate-modified body (a2) is composed of at least one skeleton selected from the group consisting of 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 4,4'-diphenylmethane diisocyanate, and a content of the 2,4'-diphenylmethane diisocyanate in the isocyanate composition is 10 mass% or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an isocyanate composition, a two-component urethane resin-forming composition, an adhesive composition, and an adhesive.

Background Art

[0002] In fields such as automobiles, building materials, ships, and aircraft, various adhesives are used to adhesively bond resins, glass, metals such as iron, aluminum, and stainless steel, ceramics, and the like. In recent years, in the fields of automobiles and aircraft, weight reduction has been promoted to improve fuel efficiency, the use ratio of materials made of plastic or fiber-reinforced plastic has been increased, and furthermore, there has been an active movement to replace metal from iron with lighter aluminum. Along with this, there is a demand for a high-performance adhesive that can firmly bond materials made of plastic or fiber-reinforced plastic and aluminum. For example, in the case of an automobile assembled by a flow operation, it is necessary to have room-temperature curability that can exhibit high adhesive strength after bonding materials at room temperature, withstand a painting process exposed to a high temperature exceeding 150°C thereafter, and finally maintain practical adhesiveness. Patent Document 1 discloses a two-component urethane adhesive composition including a polyisocyanate component obtained by adding a specific filler to a prepolymer obtained by reacting a polyisocyanate with a high-molecular-weight polyol, and a polyol component containing two types of polyols having different molecular weights. The two-component urethane adhesive composition according to Patent Document 1 can be cured at room temperature and has good adhesiveness to a steel plate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, Patent Document 1 does not mention anything about the adhesiveness at high temperatures, and further improvement of the adhesiveness at high temperatures is required. Therefore, one embodiment of the present disclosure is directed to providing an isocyanate composition, a two-component urethane resin-forming composition, an adhesive composition, and an adhesive that can exhibit excellent adhesive strength at room temperature and high temperatures.

Means for Solving the Problems

[0005] The isocyanate composition according to one embodiment of the present disclosure is a composition containing diphenylmethane diisocyanate (a1) and an isocyanurate-modified product (a2), and the isocyanurate-modified product (a2) is composed of at least one skeleton selected from the group consisting of 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 4,4'-diphenylmethane diisocyanate, and the content of 2,4'-diphenylmethane diisocyanate in the isocyanate composition is 10% by mass or more.

[0006] The two-component urethane resin-forming composition according to another embodiment of the present disclosure is composed of the above isocyanate composition and a polyol composition. The adhesive composition according to another embodiment of the present disclosure contains the above isocyanate composition or the above two-component urethane resin-forming composition. The adhesive according to another embodiment of the present disclosure contains the above adhesive composition.

Advantages of the Invention

[0007] According to one embodiment of the present disclosure, it is possible to provide an isocyanate composition, a two-component urethane resin-forming composition, an adhesive composition, and an adhesive that can exhibit excellent adhesive strength at room temperature and high temperature.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0009] Hereinafter, exemplary embodiments for carrying out the present disclosure will be described in detail. <First Embodiment (Isocyanate Composition)> A diphenylmethane diisocyanate (a1) and, an isocyanurate-modified product (a2), and an isocyanate composition containing the same, wherein the isocyanurate-modified product (a2) is composed of at least one skeleton selected from the group consisting of 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 4,4'-diphenylmethane diisocyanate, and the content of 2,4'-diphenylmethane diisocyanate in the isocyanate composition is 10% by mass or more.

[0010] [Isocyanate Composition (A)] The isocyanate composition (A) contains diphenylmethane diisocyanate (a1) and an isocyanurate-modified product (a2). The isocyanurate-modified product (a2) is 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and It is composed of at least one skeleton selected from the group consisting of 4,4'-diphenylmethane diisocyanate. The content of 2,4'-diphenylmethane diisocyanate in the isocyanate composition (A) is 10% by mass or more. The isocyanate composition (A) is preferably liquid at room temperature for ease of handling.

[0011] [[Diphenylmethane diisocyanate skeleton diisocyanate]] Examples of the diisocyanate containing a diphenylmethane diisocyanate skeleton include 4,4'-diphenylmethane diisocyanate; 2,4'-diphenylmethane diisocyanate; 2,2'-diphenylmethane diisocyanate; 2,4'-diphenylmethane diisocyanate / 4,4'-diphenylmethane diisocyanate mixture; and the like. Among these, from the viewpoint of achieving both excellent fluidity and physical properties, it is preferable to use a 2,4'-diphenylmethane diisocyanate / 4,4'-diphenylmethane diisocyanate mixture. This may contain a trace amount (5% by mass or less) of 2,2'-diphenylmethane diisocyanate.

[0012] The content of 2,4'-diphenylmethane diisocyanate in the isocyanate composition (A) is 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more. When the content of 2,4'-diphenylmethane diisocyanate is less than 10% by mass, the target product becomes solid or gel-like at room temperature, making it very difficult to handle substantially at room temperature.

[0013] The content of 2,4'-diphenylmethane diisocyanate is measured by gas chromatography (GC). Examples of the GC measurement conditions are as follows. GC measurement conditions Equipment used: GC-2025 (manufactured by Shimadzu Corporation) Column used: HP-50+ (manufactured by Agilent Technologies) Column oven temperature: 150°C to 280°C (10°C / min)

[0014] [Content of isocyanurate-modified product (a2) composed of diphenylmethane diisocyanate skeleton] The content of the isocyanurate-modified product (a2) composed of the diphenylmethane diisocyanate skeleton in the isocyanate composition (A) is 1% or more and 60% or less, preferably 10% or more and 60% or less, more preferably 20% or more and 60% or less, in terms of peak area % in gel permeation chromatography (Gel Permeation Chromatography: GPC) measurement using polystyrene as a calibration curve. Examples of the GPC measurement conditions include the following.

[0015] GPC measurement conditions Equipment used: HLC-8220 (manufactured by Tosoh Corporation) Column used: TSK guardcolumnMP (manufactured by Tosoh Corporation) TSK G3000H (manufactured by Tosoh Corporation) TSK G2000H (manufactured by Tosoh Corporation) TSK G1000H (manufactured by Tosoh Corporation) Eluent: THF Evaluation is based on the total value of the peak area % (IR) of the isocyanurate ring and its polynuclear bodies in the vicinity of the retention time of 17 minutes to 21 minutes.

[0016] [Solvent] The isocyanate composition (A) may contain a solvent, but the content of the solvent is preferably 1% by mass or less, and it is particularly preferred that it is a solvent-free type that substantially does not contain a solvent. The solvent-free type that substantially does not contain a solvent includes cases where a solvent component is contained as an impurity and cases where a solvent component in an amount that cannot be removed even by purification is contained. When the content of the solvent in the isocyanate composition (A) is 1% by mass or less, it is possible to further suppress the occurrence of dripping due to too low viscosity.

[0017] [Method for Producing Isocyanate Composition (A)] The method for producing the isocyanate composition (A) is not particularly limited, and publicly known and commonly used methods can be applied. For example, after charging a 4,4'-diphenylmethane diisocyanate / 2,4'-diphenylmethane diisocyanate mixture into a stirring container, while maintaining the temperature in the container at 60°C, a trimerization catalyst (e.g., dimethylaminomethylphenol, etc.) is added, and the nurate reaction is allowed to proceed for about 2 to 5 hours, and the catalyst is deactivated with a suitable terminator (e.g., benzoyl chloride, etc.) to obtain the isocyanate composition (A).

[0018] As the trimerization catalyst, publicly known trimerization catalysts can be used. Examples thereof include amine compounds such as 2-dimethylaminomethylphenol, 2,4,6-tris(dimethyl)phenol, 2,4-bis(dimethylaminomethyl)phenol, 2,4,6,-tris(dialkylaminoalkyl)hexahydro-S-triazine, alkali metals of carboxylic acids having 2 to 12 carbon atoms such as potassium acetate, potassium 2-ethylhexanoate, potassium octylate, and quaternary ammonium salts of carboxylic acids, etc.

[0019] The composition according to the above first embodiment has fluidity at room temperature. In this embodiment and the second embodiment described later, room temperature means 15°C or higher and 35°C or lower, and in particular, 20°C or higher and 30°C or lower. Also, in the examples described later, room temperature was set to 23°C.

[0020] <Second Embodiment (Two-Component Urethane Resin Forming Composition)> The two-component urethane resin forming composition according to an embodiment of the present disclosure is the above isocyanate composition (A) and a polyol composition (B), and consists of these. The two-component urethane resin forming composition may contain a filler (C).

[0021] The two-component urethane resin-forming composition according to this embodiment is identical to the isocyanate composition according to the above-described first embodiment, except for the polyol composition (B) and the filler (C) which may optionally be included. Therefore, in the composition according to this embodiment, the description of the parts common to the above-described first embodiment will be omitted.

[0022] [Polyol composition (B)] The polyol composition (B) contains a polyol (b1). The polyol (b1) preferably contains a polyol having an average functionality of 2 or less and a polyol having an average functionality of 3 or more. Further, the polyol composition (B) may contain additives such as a catalyst in addition to the polyol (b1).

[0023] [Polyol (b1)] Examples of the polyol (b1) include a polyol having an average functionality of 2 or less and a polyol having an average functionality of 3 or more. Examples of the polyol having an average functionality of 2 or less include polyol having two or less types of carbonate bonds, ester bonds, ether bonds, etc., such as polymer polyol, polycarbonate polyol, polyester polyol, polyether polyol, etc. Among these, from the viewpoints of strength, heat resistance, weather resistance, and durability, polycarbonate polyol is preferable, and more preferably a liquid polycarbonate polyol that can be handled at room temperature. Although the details are not clear, the reason why polycarbonate polyol is excellent in strength, heat resistance, weather resistance, and durability is presumed by the present inventors to be superior compared to the case of using polyether polyol or polyester polyol due to the high cohesive force of the carbonate bond.

[0024] Examples of the polycarbonate polyol include one or more polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, ethylene oxide or propylene oxide adducts of bisphenol A, bis(β-hydroxyethyl)benzene, xylylene glycol; and one or more carbonates such as dialkyl carbonates like dimethyl carbonate and diethyl carbonate, alkylene carbonates like ethylene carbonate and propylene carbonate, and carbonates like diphenyl carbonate, dinaphthyl carbonate, dianthryl carbonate, diphenanthryl carbonate, diindanyl carbonate; obtained from a dealcoholation reaction or a dephenolation reaction. These may contain one kind or two or more kinds.

[0025] Examples of the polyester polyol include those obtained from a polycondensation reaction of one or more of dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, succinic acid, tartaric acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, glutaconic acid, azelaic acid, sebacic acid, 1,4-cyclohexyl dicarboxylic acid, α-hydroxymuconic acid, β-hydroxymuconic acid, α-butyl-α-ethyl glutaric acid, α,β-diethyl succinic acid, maleic acid, fumaric acid or anhydrides thereof; and one or more of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, cyclohexane-1,4-diol, cyclohexane-1,4-dimethanol, dimer acid diol, ethylene oxide or propylene oxide adducts of bisphenol A, bis(β-hydroxyethyl)benzene, xylylene glycol, etc. Further, polyester-amide polyols obtained by replacing a part with low molecular polyamines such as hexamethylenediamine, isophoronediamine, monoethanolamine or low molecular amino alcohols can also be used. These may contain one kind or two or more kinds.

[0026] Examples of polyether polyols include low molecular weight polyols such as 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; or low molecular weight polyamines such as ethylenediamine, propylenediamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, xylylenediamine; polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide using a compound having two active hydrogen groups as an initiator, or polyether polyols obtained by ring-opening polymerization of alkyl glycidyl ethers such as methyl glycidyl ether, aryl glycidyl ethers such as phenyl glycidyl ether, and cyclic ether monomers such as tetrahydrofuran. These may contain one type or two or more types.

[0027] In addition, polyether polyols obtained by ring-opening polymerization of cyclic ether monomers such as 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, alkyl glycidyl ethers such as methyl glycidyl ether, and aryl glycidyl ethers such as phenyl glycidyl ether, and tetrahydrofuran can be mentioned.

[0028] Examples of polyols having an average functionality of 3 or more include glycerin, trimethylolpropane, pentaerythritol, N,N-bishydroxypropyl-N-hydroxyethylamine, triethanolamine, triisopropanolamine, monomer polyols of ethylene diamine propylene oxide modified products, monomer polyols of trimethylolpropane propylene oxide modified products, pentaerythritol propylene oxide modified products; and polycaprolactone polyols obtained by ring-opening addition of cyclic esters such as ε-caprolactone, β-butyrolactone, γ-butyrolactone, γ-valerolactone, δ-valerolactone using polyols such as glycerin, trimethylolpropane, and pentaerythritol as initiators. These may be used alone or in combination of two or more.

[0029] [Filler (C)] Examples of the filler (C) include known fillers, such as inorganic fillers and organic fillers. The filler (C) preferably contains an inorganic filler.

[0030] Examples of the inorganic filler include, but are not limited to, talc, zeolite, silica, microballoon, clay, glass balloon, carbon black, etc. These can be used alone or in combination of two or more. Among them, the combination of zeolite and talc is preferred. Zeolite has an effect of suppressing foaming, and talc has an effect of preventing dripping.

[0031] Examples of the organic filler include polyamide particles, acrylic particles, carbon nanotubes, starch, natural organic fibers, synthetic fibers, etc.

[0032] The content of the filler (C) is preferably 70% by mass or less, and more preferably 10% by mass or more and 50% by mass or less in the two-component urethane resin-forming composition. When the content of the filler (C) is 70% by mass or less, the filler (C) and other components are more uniformly mixed, and better adhesion strength and coatability can be obtained.

[0033] As a method of kneading the filler (C) and other composition components, they can be easily mixed with a three-roll mill, a planetary mixer, a revolution and rotation stirrer, etc. At this time, it is preferably carried out under a nitrogen atmosphere for the purpose of preventing moisture mixing due to the outside air.

[0034] [Solvent] The two-component urethane resin-forming composition may contain a solvent, but the content of the solvent is preferably 1% by mass or less, and a solvent-free type that substantially does not contain a solvent is particularly preferred. The solvent-free type that substantially does not contain a solvent includes cases where a solvent component is contained as an impurity and cases where a solvent component in an amount that cannot be removed even by purification is contained. When the content of the solvent in the two-component urethane resin-forming composition is 1% by mass or less, it is possible to further suppress the occurrence of dripping due to too low viscosity.

[0035] [Catalyst] A catalyst can also be used for the purpose of accelerating the reaction between the isocyanate composition (A) and the polyol composition (B). When the catalyst content is 0.05% by mass or less in the two-component urethane resin-forming composition, the decrease in the elastic modulus of the resin at high temperatures (150 to 200 °C) can be further suppressed, and it is particularly preferable in order to exhibit more excellent high-temperature adhesiveness. Examples of the catalyst include isocyanuration catalysts, urethanization catalysts, etc., and specific examples are as shown below.

[0036] [Isocyanuration catalyst] Examples of the isocyanuration catalyst include tertiary amines such as triethylamine, N-ethylpiperidine, N,N'-dimethylpiperazine, N-ethylmorpholine, Mannich bases of phenolic compounds, and potassium acetate. These isocyanuration catalysts can be used alone or in combination of two or more.

[0037] [Urethanization catalyst] As the urethanization catalyst, it can be appropriately selected from known catalysts, and examples thereof include amine-based catalysts, imidazole-based catalysts, metal catalyst systems, etc.

[0038] [Amine-based catalyst] Examples of the amine-based catalyst 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"-pentamethyldipropylenetriamine, N,N,N',N'-tetramethylhexamethylenediamine, bis(2-dimethylaminoethyl)ether, etc.

[0039] [Imidazole-based catalyst] Examples of imidazole-based catalysts include 1-methylimidazole, 1,2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethylaminopropylimidazole, and the like.

[0040] [Metal-based catalyst] Examples of metal-based catalysts include organotin catalysts such as stannous diacetate, stannous dioctoate, stannous dioleate, stannous dilaurate, dibutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, dioctyltin dilaurate, and the like.

[0041] [Other additives] The composition may further contain, as additives, a reaction inhibitor, an antioxidant, an antifoaming agent, etc., if necessary.

[0042] The two-component urethane resin-forming composition according to the above-described second embodiment can exhibit excellent adhesive strength at room temperature and high temperature.

[0043] <Third Embodiment (Composition for Adhesive, Adhesive)> The composition for an adhesive according to an embodiment of the present disclosure contains the above-described composition (first embodiment, second embodiment). The composition for an adhesive may be the above-described composition itself, or may further contain other components. Also, the adhesive according to an embodiment of the present disclosure contains the above-described composition for an adhesive. The adhesive may be the above-described composition for an adhesive itself, or may further contain other components.

[0044] The adhesive according to an embodiment of the present disclosure can be used as an adhesive for various applications, and examples include the automotive field, the display field, the recording medium field, the electronic material field, the battery field, the optical component field, the construction field, the electronic device field, the aviation field, and the like. Examples of the automotive field include automotive structural parts, switch parts, headlamps, engine internal parts, electrical components, drive engines, brake oil tanks, and the like. Examples of the display field include liquid crystal displays, organic electroluminescence, light emitting diode display devices, and the like. Examples of the recording medium field include video disks, CDs, DVDs, MDs, pickup lenses, VCM magnets, spindle motors, hard disk peripheral members, Blu-ray disks, and the like. Examples of the electronic material field include electronic components, electric circuits, electrical contacts, or semiconductor elements, etc. Among these applications, more specifically, encapsulating materials, die bonding agents, conductive adhesives, anisotropic conductive adhesives, interlayer adhesives for multilayer substrates including build-up substrates, and the like can be mentioned. Examples of the battery field include lithium ion batteries, manganese batteries, alkaline batteries, nickel-based batteries, fuel cells, silicon-based solar cells, dye-sensitized solar cells, organic solar cells, and the like. Examples of the optical component field include around optical switches in optical communication systems, optical fiber materials around optical connectors, optical passive components, optical circuit components, around optoelectronic integrated circuits, and the like. Examples of the electronic device field include camera modules and the like.

Examples

[0045] The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[0046] (Example 1) Into a 2 L stirring container filled with nitrogen, a 2,4'-diphenylmethane diisocyanate / 4,4'-diphenylmethane diisocyanate mixture was charged, and after the liquid temperature was set to 60 °C, 2-dimethylaminomethylphenol was charged as a catalyst to proceed with the nuration reaction. A terminator (diphenyldichlorosilane) was charged at an appropriate timing to deactivate the catalyst, and an isocyanate composition (A) was obtained.

[0047] (Examples 2 to 6, Comparative Examples 7 to 8) Furthermore, in Examples 2 to 6 and Comparative Examples 7 to 8, an isocyanate composition (A) was obtained in the same manner as in Example 1 according to the formulations shown in Table 1. However, the timing of adding the terminator to deactivate the catalyst was appropriately adjusted in each example and carried out at a timing different from that of Example 1.

[0048] For the isocyanate compositions (A) obtained in Examples 1 to 6 and Comparative Examples 7 to 8, the content (PA%) of the isocyanurate-modified product (a2) was measured according to the GPC measurement conditions described above. This was designated as "isocyanurate skeleton" (PA%) in Table 1. The content (%) of 2,4'-diphenylmethane diisocyanate was measured by GC according to the GC measurement conditions described above.

[0049] (Examples 9 to 14, Comparative Examples 15 to 16) Also, according to the blending ratios shown in Table 2, polyol (b1) was charged and stirred in a 5 L stirring container filled with nitrogen. While maintaining the temperature in the stirring container at 40 to 70°C, it was mixed and stirred for about 1 to 3 hours to obtain various polyol compositions (B).

[0050] Furthermore, in Examples 9 to 14 and Comparative Examples 15 to 16, a filler (C) was added to the isocyanate composition (A) or the polyol composition (B) according to the formulations shown in Table 2 and mixed using a planetary mixer (trade name: Kakuhunter, manufactured by Shashin Kagaku Co., Ltd.).

[0051] Next, according to the formulation shown in Table 2, a mixture consisting of the isocyanate composition (A), the polyol composition (B), and the filler (C) was mixed uniformly with a stainless steel spatula to prepare an adhesive. The obtained adhesive was uniformly applied to an aluminum plate (length 100 mm × width 25 mm × thickness 1 mm; A6061, T-Zr treated product) to prepare an adhesion test piece conforming to JIS K 6850:1999.

[0052] The abbreviations of the raw materials shown in Table 1 and Table 2 are as follows. [Raw materials] (1) Isocyanate composition (A) · "NM"; Millionate NM (manufactured by Tosoh Corporation) 4,4'-Diphenylmethane diisocyanate / 2,4'-Diphenylmethane diisocyanate mixture, NCO content = 33.5%, f = 2 · "MT"; Millionate MT (manufactured by Tosoh Corporation) 4,4'-Diphenylmethane diisocyanate NCO content = 33.5%, f = 2 · "PTMG850"; PTMG850 (manufactured by Mitsubishi Chemical Corporation), Polytetramethylene glycol, hydroxyl value 132 KOHmg / g, f = 2

[0053] (2) Polyol composition (B) · "PCD#500"; Kuraray Polyol C-590 (manufactured by Kuraray Co., Ltd.), Polycarbonate polyol, hydroxyl value = 224 KOHmg / g, f = 2 · "MA170"; Reocon MA-170 (manufactured by Lion Specialty Chemicals Co., Ltd.), N,N-Bishydroxypropyl-N-hydroxyethylamine, Hydroxyl value = 950 KOHmg / g, f = 3

[0054] (3) Filler (C) · "Zeolite"; Zeolam A-3 (manufactured by Tosoh Corporation) · "Talc"; Crown Talc R (manufactured by Matsumura Sangyo Co., Ltd.)

[0055]

Table 1

[0056] * Fluidity: When 10 cc of the isocyanate composition (A) is poured into a 30 cc vial, if it flows, it is rated as A; if it does not flow, it is rated as D.

[0057]

Table 2

[0058] <Preparation and Evaluation Criteria of Test Specimens> (1) Adhesion Strength at Room Temperature [Cured at 23°C for 16 hours → 180°C for 20 minutes (measured in 23°C environment)] Adhesive was applied to the surfaces of two aluminum plates (length 100 mm × width 25 mm × thickness 1 mm; A6061, T-Zr treated product), and they were adhered so that the overlapping area of the aluminum plates was length 12.5 mm × width 25 mm. After leaving it for 16 hours under the condition of 23°C, it was further cured at 180°C for 20 minutes to prepare an adhesion test specimen. At this time, glass beads were used to adjust the thickness of the adhesive layer to 0.25 mm, and an adhesion test specimen was obtained. Regarding the adhesion test specimen prepared as described above, the tensile shear strength of the adhesion part was measured by a tensile testing machine (product name: AutoCom universal testing machine AC-10kN-C, manufactured by T.S.E. Co., Ltd.). This measurement was carried out in accordance with the tensile shear adhesion strength of adhesives in JIS K6850:1999. The measurement conditions were a temperature of 23°C, a chuck distance of 111.5 mm, and a test speed of 10 mm / min.

[0059] (2) Adhesion Strength at High Temperature [180°C for 20 minutes (measured in 180°C environment)] In order to confirm the heat resistance of the test specimen (adhesive resin) after curing the adhesive at 23°C for 16 hours, after leaving it at 180°C for 20 minutes, the tensile shear strength of the adhesion part was measured in the same manner as in (1) above. However, the measurement condition was changed to a temperature of 180°C, and the rest was the same.

[0060] <Evaluation Results> In Examples 1 to 6, all contained 10% by mass or more of 2,4'-diphenylmethane diisocyanate, and had fluidity at room temperature and were good. On the other hand, in Comparative Examples 7 and 8, they did not contain 2,4'-diphenylmethane diisocyanate, were solid at normal temperature, and could not be used for resinification at normal temperature.

[0061] In Examples 9 to 14, an isocyanate composition containing an isocyanurate skeleton was used, and good adhesive strength was confirmed both at room temperature and at high temperature. On the other hand, in Comparative Examples 15 and 16, the isocyanurate skeleton was not contained in the isocyanate composition, and the adhesive strength at room temperature was good, but the adhesive strength at high temperature was not sufficient.

Claims

1. An isocyanate composition for an adhesive, comprising a diphenylmethane diisocyanate (a1) and an isocyanurate-modified product (a2), wherein the isocyanurate-modified product (a2) is composed of at least one skeleton selected from the group consisting of 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 4,4'-diphenylmethane diisocyanate, the content of 2,4'-diphenylmethane diisocyanate in the isocyanate composition is 10% by mass or more, the ratio of the isocyanurate-modified product (a2) in the isocyanate composition is in the range of 10% or more in terms of peak area% in gel permeation chromatography measurement using polystyrene as a calibration curve, and the isocyanate composition for an adhesive is solvent-free.

2. A two-component urethane resin-forming composition for an adhesive, comprising the isocyanate composition for an adhesive according to Claim 1 and a polyol composition.

3. A two-component urethane resin-forming composition comprising an isocyanate composition and a polyol composition, wherein the isocyanate composition contains a diphenylmethane diisocyanate (a1) and an isocyanurate-modified product (a2), the isocyanurate-modified product (a2) is composed of at least one skeleton selected from the group consisting of 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, and 4,4'-diphenylmethane diisocyanate, the content of 2,4'-diphenylmethane diisocyanate in the isocyanate composition is 10% by mass or more, the ratio of the isocyanurate-modified product (a2) in the isocyanate composition is in the range of 10% or more in terms of peak area% in gel permeation chromatography measurement using polystyrene as a calibration curve, and the content of the solvent is 1% by mass or less.

5. The two-component urethane resin-forming composition according to Claim 2, which is solvent-free.

6. The two-component urethane resin-forming composition according to any one of Claims 2 to 4, wherein the polyol composition contains a polycarbonate polyol.

6. ​ ​ An adhesive composition comprising the isocyanate composition for adhesives according to claim 1, the two-component urethane resin-forming composition for adhesives according to claim 2, or the two-component urethane resin-forming composition according to any one of claims 3 to 5.

7. An adhesive comprising the adhesive composition according to claim 6 and a filler.

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