Adhesive set and adhesive

Abstract

To provide a two-pack type adhesive which has sufficient curability at room temperature even in the presence of oxygen, and suppresses liquid sagging when being coated onto the adherend.SOLUTION: An adhesive set includes a first liquid containing one or more kinds of acrylic monomers having two or more (meth)acryloyl groups, and an epoxy resin having two or more epoxy groups, and a second liquid containing a curing agent containing a compound having a nucleophilic reactive group reactive with both the epoxy group and the (meth)acryloyl groups. The acrylic monomer contains a bifunctional acrylic monomer having two (meth)acryloyl groups. A ratio of the bifunctional acrylic monomer to the total mass of the acrylic monomer is 75 mass% or more.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an adhesive set and an adherent body.

Background Art

[0002] Conventionally, as one type of adhesive, a two-component adhesive using a (meth)acrylic monomer has been known (for example, Patent Document 1). In the case of a conventional two-component adhesive using a (meth)acrylic monomer, generally, the polymerization of the (meth)acrylic monomer proceeds by a redox catalyst system formed by a polymerization initiator and a reducing agent, and as a result, the adhesive cures.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] One aspect of the present invention provides a two-component adhesive that has sufficient curability at room temperature even in the presence of oxygen and suppresses dripping when applied to an adherent body.

Means for Solving the Problems

[0005] One aspect of the present invention provides an adhesive set including a first liquid containing one or more acrylic monomers having two or more (meth)acryloyl groups and an epoxy resin having two or more epoxy groups, and a second liquid containing a curing agent including a compound having a nucleophilic reactive group that reacts with both an epoxy group and a (meth)acryloyl group. The acrylic monomer includes a bifunctional acrylic monomer having two (meth)acryloyl groups, and the ratio of the bifunctional acrylic monomer to the total mass of the acrylic monomer is 75% by mass or more.

Effects of the Invention

[0006] According to one aspect of the present invention, a two-component adhesive is provided that has sufficient curability at room temperature even in the presence of oxygen, and that suppresses dripping when applied to a substrate. The adhesive set according to one aspect of the present invention may also have excellent properties in terms of good discharge from a nozzle, etc., and a sufficiently long pot life. [Brief explanation of the drawing]

[0007] [Figure 1] This is a cross-sectional view showing one embodiment of the adhesive. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below. However, the present invention is not limited to the following embodiments. In this specification, (meth)acryloyl means acryloyl or methacryloyl, and the same applies to other similar expressions.

[0009] An adhesive set according to one embodiment is a two-component adhesive consisting of a first liquid and a second liquid. The first liquid contains one or more acrylic monomers having two or more (meth)acryloyl groups, and an epoxy resin having two or more epoxy groups. The second liquid contains a curing agent containing a compound having a nucleophilic reactive group that reacts with both epoxy groups and (meth)acryloyl groups.

[0010] Acrylic monomers are difunctional or multifunctional compounds having an acryloyl group, a methacryloyl group, or both. The number of (meth)acryloyl groups in an acrylic monomer may be 2 to 4.

[0011] The acrylic monomer contained in the first solution mainly consists of a difunctional acrylic monomer having two (meth)acryloyl groups. Specifically, the ratio of the difunctional acrylic monomer to the total mass of the acrylic monomer contained in the first solution is 75% by mass or more. The ratio of the difunctional acrylic monomer to the total mass of the acrylic monomer may be 76% by mass or more, 77% by mass or more, 78% by mass or more, 79% by mass or more, 80% by mass or more, 81% by mass or more, 82% by mass or more, 83% by mass or more, 84% by mass or more, 85% by mass or more, 86% by mass or more, 87% by mass or more, 88% by mass or more, 89% by mass or more, 90% by mass or more, 91% by mass or more, 92% by mass or more, 93% by mass or more, 94% by mass or more, 95% by mass or more, 96% by mass or more, 97% by mass or more, 98% by mass or more, 99% by mass or more, or 100% by mass, from the viewpoint of a long pot life, etc.

[0012] The difunctional acrylic monomer may be, for example, a poly(meth)acrylate of an aliphatic polyol. Examples of poly(meth)acrylates of aliphatic polyols include diethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and polyethylene polypropylene glycol di(meth)acrylate. Other examples of difunctional acrylic monomers include 2,2'-di(meth)acryloyloxydiethyl phosphate, ethylene oxide-modified phosphate di(meth)acrylate, urethane acrylate, and epoxy acrylate. An example of a commercially available urethane acrylate is EBECRYL230 (Daicel Ornex). An example of a commercially available epoxy acrylate is EBECRYL230 (Daicel Ornex). These difunctional acrylic monomers can be used individually or in combination of two or more.

[0013] An acrylic monomer may have two or more (meth)acryloyl groups and an epoxy group. In this specification, compounds having two or more (meth)acryloyl groups and one or more epoxy groups are classified as difunctional or polyfunctional acrylic monomers based on the number of (meth)acryloyl groups. A difunctional acrylic monomer may be a compound having two (meth)acryloyl groups and no epoxy group.

[0014] The first solution may further contain, in addition to the difunctional acrylic monomer, a polyfunctional acrylic monomer having three or more (meth)acryloyl groups. Examples of polyfunctional acrylic monomers include trifunctional (meth)acrylic monomers such as trimethylolpropane tri(meth)acrylate and pentaerythritol tri(meth)acrylate, and tetrafunctional (meth)acrylic monomers such as ditrimethylolpropanetetra(meth)acrylate.

[0015] The first solution may further contain a monofunctional acrylic monomer having one (meth)acryloyl group. The proportion of the monofunctional acrylic monomer may be 0-10% by mass, 0-5% by mass, 0-2% by mass, or 0-1% by mass relative to the total amount of the difunctional acrylic monomer and the polyfunctional acrylic monomer.

[0016] The epoxy resin can be any bifunctional or multifunctional epoxy resin. The number of epoxy groups in the epoxy resin may be 2 to 4.

[0017] Examples of epoxy resins include diglycidyl ether type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD ​​type epoxy resin, bisphenol S type epoxy resin, and hydrogenated bisphenol A type epoxy resin; novolac type epoxy resins such as phenol novolac type epoxy resin and cresol novolac type epoxy resin; biphenyl type epoxy resins such as biphenyl type epoxy resin and biphenyl aralkyl type epoxy resin; glycidyl ester type epoxy resins which are reaction products of polybasic acids (e.g., phthalic acid, dimer acid) and epichlorohydrin; glycidylamine type epoxy resins which are reaction products of amine compounds (e.g., p-aminophenol, diaminodiphenylmethane, isocyanuric acid) and epichlorohydrin; and aliphatic epoxy resins.

[0018] The epoxy resin may further have (meth)acryloyl groups. In this specification, a compound having two or more epoxy groups and one (meth)acryloyl group is classified as an epoxy resin. The epoxy resin may also be a compound having two or more epoxy groups but no (meth)acryloyl group.

[0019] The first liquid may further contain a monofunctional acrylic monomer having one (meth)acryloyl group, a monofunctional epoxy resin having one epoxy group, or both.

[0020] The content of acrylic monomers having two or more (meth)acryloyl groups in the first liquid may be 10-90% by mass, 20-80% by mass, 30-70% by mass, or 40-60% by mass, relative to the total amount of acrylic monomers having two or more (meth)acryloyl groups and epoxy resin having two or more epoxy groups. The total amount of acrylic monomers having two or more (meth)acryloyl groups and epoxy resin having two or more epoxy groups may be 50-100% by mass, 60-100% by mass, 70-100% by mass, 80-100% by mass, 85-100% by mass, or 90-100% by mass, relative to the amount of the first liquid.

[0021] The curing agent contained in the second liquid is a component that cures the mixture (adhesive) of the first liquid and the second liquid by reacting with an epoxy resin, an acrylic monomer, or both. The curing agent includes at least a compound having a nucleophilic reactive group that reacts with both an epoxy group and a (meth)acryloyl group. This compound may have 2 to 4 or 2 to 3 nucleophilic reactive groups.

[0022] The nucleophilic reactive group may be, for example, an aliphatic amino group or a thiol group. From the perspective of reactivity with the (meth)acryloyl group, the nucleophilic reactive group may be an aliphatic amino group. Examples of compounds having an aliphatic amino group include aliphatic amine compounds having two or more primary aliphatic amino groups such as 1,3-bis(aminomethyl)cyclohexane and 1,6-hexanediamine. Examples of commercially available products of compounds having an aliphatic amino group include jER Cure 3080 (manufactured by Mitsubishi Chemical Corporation, trade name).

[0023] The curing agent contained in the second liquid may further contain a compound that reacts substantially only with an epoxy resin. Examples of such compounds include aromatic amine compounds.

[0024] The content of the compound having a nucleophilic reactive group in the second liquid may be 30 to 100% by mass, 40 to 100% by mass, 50 to 100% by mass, 60 to 100% by mass, 70 to 100% by mass, 80 to 100% by mass, 85 to 100% by mass, or 90 to 100% by mass based on the amount of the second liquid.

[0025] The first liquid, the second liquid, or both may further contain an inorganic filler. By blending an inorganic filler, dripping of the liquid when applied to the adherend can be more effectively suppressed. Examples of the inorganic filler include silica particles, calcium carbonate particles, and glass beads. The silica particles may be, for example, unmodified silica fillers or silica fillers chain-modified with an alkyl chain or a (meth)acryloyl group or the like.

[0026] The inorganic filler content in the first liquid may be 0-30% by mass, 0-20% by mass, or 0-15% by mass relative to the volume of the first liquid. The inorganic filler content in the second liquid may be 0-30% by mass, 0-20% by mass, or 0-15% by mass relative to the volume of the second liquid. The inorganic filler content in the first liquid and the inorganic filler content in the second liquid may be the same or different.

[0027] The first liquid, the second liquid, or both may further contain a silane coupling agent. The silane coupling agent may be, for example, a compound having a hydrolyzable silyl group and a functional group that reacts with at least one of an acrylic monomer, an epoxy resin, or a curing agent. The hydrolyzable silyl group is, for example, a group having a silicon atom and 1 to 3 alkoxy groups bonded to the silicon atom. The number of carbon atoms in the alkoxy group bonded to the silicon atom may be, for example, 1 to 4. Examples of functional groups that react with at least one of an acrylic monomer or an epoxy resin include amino groups such as primary and secondary amino groups, epoxy groups, mercapto groups, and (meth)acryloyl groups. In this specification, compounds having a hydrolyzable silyl group and a (meth)acryloyl group are classified as silane coupling agents.

[0028] Specific examples of silane coupling agents include 3-glycidyloxypropyltrimethoxysilane and 3-aminopropyltrimethoxysilane.

[0029] Commercially available silane coupling agents include, for example, KBM-303, KBM-402, KBM-403, KBE-402, KBE-403, KBM-4803, KBM-502, KBM-503, KBE-502, KBE-503, KBM-5103, KBM-5803, KBM-602, KBM-603, KBM-903, KBE-903, KBE-9103P, KBM-573, KBM-575, KBM-802, and KBM-803 (all manufactured by Shin-Etsu Chemical Co., Ltd., trade names).

[0030] The silane coupling agent content in the first solution may be 0 to 5% by mass, or 0 to 3% by mass, relative to the volume of the first solution. The silane coupling agent content in the second solution may be 0 to 5% by mass, or 0 to 3% by mass, relative to the volume of the second solution.

[0031] The first liquid, the second liquid, or both may further contain other components as needed. Examples of other components include pigments (e.g., carbon black, titanium dioxide particles) and elastomers.

[0032] The elastomer may be, for example, a triblock copolymer of methyl methacrylate-butyl acrylate-methyl methacrylate, a biterminal acrylate polymer, or a combination thereof. The elastomer content may be 10 to 50% by mass, or 20 to 40% by mass, based on the total amount of one or more acrylic monomers having two or more (meth)acryloyl groups, the epoxy resin, the compound having a nucleophilic reactive group that reacts with either the epoxy group or the (meth)acryloyl group, and the elastomer.

[0033] Either the first or second liquid may contain a pigment. Alternatively, both the first and second liquids may contain a pigment, in which case the pigment in the first liquid and the pigment in the second liquid may be different. When the adhesive set contains a pigment in this way, the mixing state of the first and second liquids can be visualized when they are mixed together. A mixture of the first and second liquids that is sufficiently and uniformly dispersed in the pigment tends to yield better adhesive strength.

[0034] The adhesive sets illustrated above are used to bond adherends together using an adhesive which is a mixture of a first liquid and a second liquid, in order to obtain a desired adhesive having two or more adherends and an adhesive layer that bonds them together. Figure 1 is a cross-sectional view showing one embodiment of the adhesive. The adhesive 30 shown in Figure 1 has two adherends 11 and 12 and an adhesive layer 20 interposed between the two adherends 11 and 12 to bond them together. The adhesive layer 20 can be a cured product formed from the adhesive set according to the above embodiment.

[0035] The adherend may be a molded body made of metal such as steel, iron, copper, tinplate, aluminum, or stainless steel, a resin, or carbon fiber reinforced plastic (CFRP). Two or more adherends may be molded bodies made of the same or different materials.

[0036] A method for obtaining an adhesive having two adherends using an adhesive set includes, for example, arranging the two adherends with a gap between them, injecting a first liquid and a second liquid into the gap between the two adherends, and curing the adhesive, which is a mixture of the first liquid and the second liquid. The first liquid and the second liquid may be mixed almost simultaneously with their injection into the gap between the two adherends, or they may be mixed before being injected between the two adherends. The first liquid and the second liquid, or a mixture thereof (adhesive), is injected between the two adherends, for example, using a mixing nozzle.

[0037] A method for obtaining an adhesive may include applying an adhesive mixture of a first liquid and a second liquid onto one of the adherends, bonding the two adherends together with the applied adhesive in between, and then curing the adhesive. When the adhesive hardens, an adhesive layer is formed between the two adherends, bonding them together.

[0038] The mixing ratio of the first and second liquids is adjusted to ensure proper curing of the adhesive, taking into consideration the stoichiometric ratio of the reaction between the acrylic monomer and epoxy resin contained in the first liquid and the curing agent contained in the second liquid. For example, the volume ratio of the first liquid to the second liquid may be 0.5 to 5.0.

[0039] The curing conditions are adjusted so that the adhesive cures properly. For example, the adhesive may be cured in an environment of 10-40°C. The curing time is adjusted, for example, between 1 hour and 1 week. The adhesive may also be heated, in which case the heating temperature may be, for example, 40-120°C. [Examples]

[0040] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples.

[0041] 1. Preparation of the adhesive set Using the following raw materials, the first and second solutions with the compositions shown in Table 1 or Table 2 were prepared. (1) Acrylic monomer (Bifunctional acrylic monomer) • 1,6-Hexanediol diacrylate (Product name: Viscoat 230, Shin-Nakamura Chemical Industry Co., Ltd.) (Trifunctional acrylic monomer) • Trimethylolpropane triacrylate (product name: TMPTA, Daicel Ornex Co., Ltd.) (Tetrafunctional acrylic monomer) • Ditrimethylolpropanetetraacrylate (Product name: EBECRYL140, Daicel Ornex Co., Ltd.) (2) Epoxy resin • Bisfer F-type epoxy resin (Product name: EPICLON830, DIC Corporation) (3) Hardener • 1,3-bisaminomethylcyclohexane • Aliphatic amine-based curing agent (Product name: jER Cure 3080, Mitsubishi Chemical Corporation) (4) Fillers (inorganic fillers) • Silica particles (Product name: Aerosil 200V, Aerosil Japan Co., Ltd.) (5) Silane coupling agents • 3-Glycidyloxypropyltrimethoxysilane (Product name: KBM-403, Shin-Etsu Chemical Co., Ltd.) • 3-Aminopropyltrimethoxysilane (Product name: KBM-903, Shin-Etsu Chemical Co., Ltd.) (6) Elastomer • Triblock copolymer of methyl methacrylate, butyl acrylate, and methyl methacrylate (Product name: Clarity LA3320 or LA2140, Kuraray Co., Ltd.) • Acrylate polymer at both ends (Product name: XMAP RC110C or RC310C, Kaneka Corporation)

[0042] 2. Evaluation The adhesive sets were evaluated using the following method. The evaluation results are shown in Tables 1 and 2. (1) Dripping The first and second liquids were mixed in a volume ratio of 2:1 using a static mixer, and the resulting adhesive was applied to a vertically positioned aluminum plate. The dripping of the adhesive mixture after application was observed, and the time until dripping of 1.0 mm or more occurred from the time of application was measured. Based on the measurement results, each adhesive set was evaluated according to the following evaluation criteria. A: More than 30 minutes B: More than 10 minutes but less than 30 minutes C: Within 10 minutes

[0043] (2) Room temperature curability The first and second liquids were mixed in a volume ratio of 2:1 using a static mixer, and the resulting adhesive was applied to an aluminum plate. The applied adhesive was cured for one day in an air environment at 25°C, and then visually inspected to see if it had hardened. Adhesives that showed signs of hardening were classified as "A," and those that did not show signs of hardening were classified as "C."

[0044] (3) Pot life The first and second liquids were mixed in a volume ratio of 2:1 using a static mixer, and the resulting adhesive was applied to an aluminum plate. The applied adhesive was left to stand at 25°C for 30 minutes. Then, the adhesive was sandwiched between another aluminum plate, and the resulting laminate was cured at 25°C for 3 days. After curing, the adhesive strength (shear strength) between the two aluminum plates was measured. A higher shear strength indicates a longer pot life. Based on the shear strength value, the pot life was determined according to the following criteria. A: Shear strength of 8 MPa or more B: Shear strength between 4 MPa and less than 8 MPa C: Shear strength less than 4 MPa

[0045] [Table 1]

[0046] [Table 2] [Explanation of Symbols]

[0047] 11,12...Adherent, 20...Adhesive layer, 30...Adhesive.

Claims

1. A first liquid containing one or more acrylic monomers having two or more (meth)acryloyl groups, and an epoxy resin having two or more epoxy groups, The second solution contains a curing agent containing a compound having a nucleophilic reactive group that reacts with both an epoxy group and a (meth)acryloyl group, The acrylic monomer comprises a difunctional acrylic monomer having two (meth)acryloyl groups, and the ratio of the difunctional acrylic monomer to the total mass of the acrylic monomer is 75% by mass or more. The first liquid comprises a silane coupling agent having an epoxy group, and the second liquid comprises a silane coupling agent having an amino group. Adhesive set.

2. The adhesive set according to claim 1, wherein the silane coupling agent having an epoxy group comprises 3-glycidyloxypropyltrimethoxysilane, and the silane coupling agent having an amino group comprises 3-aminopropyltrimethoxysilane.

3. The adhesive set according to claim 1 or 2, wherein the nucleophilic reactive group is an aliphatic amino group.

4. The adhesive set according to any one of claims 1 to 3, wherein at least one of the first liquid or the second liquid further contains an inorganic filler.

5. The adhesive set according to any one of claims 1 to 4, wherein only one of the first liquid or the second liquid further contains a pigment.

6. The adhesive set according to any one of claims 1 to 5, wherein the first liquid and the second liquid each further contain a pigment, and the pigment contained in the first liquid and the pigment contained in the second liquid are different.

7. It comprises two or more adherends and an adhesive layer for bonding the two or more adherends, An adhesive body wherein the adhesive layer is a layer formed by the adhesive set described in any one of claims 1 to 6.

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