JP2021098824A - Adhesive composition, and laminate - Google Patents

Abstract

To provide an adhesive composition which has sufficient adhesive force, flexibility and base material adhesion and is suitable for fields such as an automobile, a housing material, a vessel and an aircraft, and a laminate formed of the composition.SOLUTION: An adhesive composition contains a urethane-acryl composite resin (C) in which a urethane unit (A) and a (meth)acryloyl unit (B) are connected to each other by a chain transfer agent residue, a crosslinking agent (D), and a reactive diluent (E). The (meth)acryloyl unit (B) has a structural unit derived from a (meth)acryl monomer (b1) having a hydroxyl group and a structural unit derived from an ethylenically unsaturated monomer (b2) having at least one group selected from the group consisting of a ketone group and an aldehyde group.SELECTED DRAWING: None

Description

The present invention relates to an adhesive composition suitable for the fields of automobiles, building materials, ships, aircraft, etc., which has sufficient adhesive strength, flexibility, and substrate adhesion, and a laminate formed from the composition.

In the fields of automobiles, building materials, ships, aircraft, etc., various structural adhesives are used to bond and fix metals such as resin, glass, iron, aluminum, and stainless steel, and ceramics. In recent years, in the fields of automobiles and aircraft, weight reduction has been promoted to improve fuel efficiency, the ratio of materials made of plastic and fiber reinforced plastic (hereinafter referred to as FRP) has been increased, and the metal is made of iron, which is lighter than aluminum. There is an active movement to replace them with, and there is a demand for an adhesive that can firmly bond these. Further, from the viewpoint of workability and reduction of environmental load, an adhesive containing no volatile organic compounds is required.

However, for example, when a metal such as aluminum and a material having a different linear expansion coefficient such as FRP are bonded, a high stress is applied to the adhesive layer due to the difference in expansion coefficient between the materials caused by the temperature change in the manufacturing process or the operating temperature environment. , There is a problem of accelerating the destruction or deterioration of the adhesive layer.

In response to such problems, for example, in Patent Documents 1 to 3, there is a method of adding long-chain polyamines, nano-dispersed rubber-like particles, or the like to an epoxy compound having high adhesiveness to metals or FRP for the purpose of stress relaxation. Proposed. However, although these methods can impart a certain degree of flexibility, the obtained adhesive layer is still hard and brittle, and the effect is not sufficient.

Special Table 2018-506635 International Publication No. 2007/025007 Japanese Unexamined Patent Publication No. 2015-182248

The present invention provides an adhesive composition suitable for the fields of automobiles, building materials, ships, aircraft, etc., which has sufficient adhesive strength, flexibility, and substrate adhesion, and a laminate formed from the composition. The purpose is to do.

As a result of diligent studies to solve the above problems, it was found that the above problems can be solved by the following embodiments, and the present invention has been completed.

In the embodiment of the present invention, a urethane-acrylic composite resin (C) in which a urethane unit (A) and a (meth) acryloyl unit (B) are linked by a chain transfer agent residue, a cross-linking agent (D), and a reactive dilution are used. An adhesive composition containing an agent (E), wherein the (meth) acryloyl unit (B) is a structural unit derived from a (meth) acrylic monomer (b1) having a hydroxyl group, and a ketone group and an aldehyde group. The present invention relates to an adhesive composition having a structural unit derived from an ethylenically unsaturated monomer (b2) having at least one group selected from the group consisting of.

Another embodiment of the present invention relates to the above-mentioned adhesive composition in which the urethane unit (A) and the (meth) acryloyl unit (B) are linked by a residue of a chain transfer agent having an amino group.

In another embodiment of the present invention, the content of the structural unit derived from the (meth) acrylic monomer (b1) having a hydroxyl group is 15 to 60 parts by mass in 100 parts by mass of the (meth) acryloyl unit (B). The content of the structural unit derived from the ethylenically unsaturated monomer (b2) having at least one group selected from the group consisting of a ketone group and an aldehyde group in the molecule is 5 to 30 parts by mass. Regarding adhesive compositions.

Another embodiment of the present invention relates to the above-mentioned adhesive composition in which the content of the urethane unit (A) is 60 to 85 parts by mass in 100 parts by mass of the urethane-acrylic composite resin (C).

In another embodiment of the present invention, the ethylenically unsaturated monomer (b2) having at least one group selected from the group consisting of a ketone group and an aldehyde group in the molecule has a β-diketone structure. Regarding the adhesive composition.

Another embodiment of the present invention relates to the above-mentioned adhesive composition in which the urethane-acrylic composite resin (C) has a number average molecular weight of 9,000 to 50,000.

Another embodiment of the present invention relates to a laminate having an adhesive layer formed from the above-mentioned adhesive composition on a base material.

INDUSTRIAL APPLICABILITY The present invention provides an adhesive composition suitable for the fields of automobiles, building materials, ships, aircraft, etc., which has sufficient adhesive strength, flexibility, and substrate adhesion, and a laminate formed from the composition. can do.

The adhesive composition of the present invention comprises a urethane-acrylic composite resin (C) in which a urethane unit (A) and a (meth) acryloyl unit (B) are linked by a chain transfer agent residue, a cross-linking agent (D), and a reaction. The (meth) acryloyl unit (B) containing the sex diluent (E) is composed of a structural unit derived from the (meth) acrylic monomer (b1) having a hydroxyl group, and a ketone group and an aldehyde group in the molecule. It is characterized by having a structural unit derived from an ethylenically unsaturated monomer (b2) having at least one group selected from the group.
The present invention will be described in detail below.

<Urethane / acrylic composite resin (C)>
The urethane-acrylic composite resin (C) of the present invention may have a structure in which the urethane unit (A) and the (meth) acryloyl unit (B) are linked by a chain transfer agent residue, and the production method thereof is as long as it has a structure. Although not limited, it can be preferably produced by the following method.
First, a urethane unit (A) having isocyanate groups at both ends, which is obtained by reacting a polyol and polyisocyanate, is formed (hereinafter, step 1). Next, a chain transfer agent and a reactive diluent (E) are added to synthesize a urethane prepolymer having chain transfer agent residues at both ends of the urethane unit (A) (hereinafter, step 2). Then, using the chain transfer agent residue of the obtained urethane prepolymer, at least one selected from the group consisting of a (meth) acrylic monomer (b1) having a hydroxyl group, a ketone group and an aldehyde group in the molecule. The ethylenically unsaturated monomer containing the ethylenically unsaturated monomer (b2) having the group of is chain-transfer polymerized in the presence of a polymerization initiator to form a (meth) acryloyl unit (B) (hereinafter,). , Step 3).
In this way, the urethane unit (A) and the (meth) acryloyl unit (B) having at least one group selected from the group consisting of a hydroxyl group and a ketone group and an aldehyde group in the molecule are linked transfer agent residues. The urethane / acrylic composite resin (C) connected by the above can be obtained. All of these reactions may be carried out using a solvent, but it is preferable to produce without using a solvent from the viewpoint of odor and workability. When a solvent is used, it is preferable to remove the solvent under reduced pressure or normal pressure in the middle of the reaction or after the reaction is completed.

<Urethane unit (A)>
The urethane-acrylic composite resin (C) in the present invention has a structure in which a urethane unit (A) and a (meth) acryloyl unit (B) are linked by a chain transfer agent residue, and the urethane unit is , Polyol can be formed by reacting with polyisocyanate.

<Polyol>
Examples of the polyol constituting the urethane unit include polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, vegetable oil-based polyols, and other polyols. These may be used individually by 1 type, and may be used in combination of 2 or more type.

(Polyether polyol)
Examples of the polyether polyol include polymers such as methylene oxide, ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran, or copolymers such as polyethylene glycol, polypropylene glycol, poly (ethylene / propylene) glycol, and polytetramethylene glycol. Glycols; hexanediol, methylhexanediol, heptanediol, octanediol or condensates of mixtures thereof; compounds having two or more active hydrogen groups, such as methylene oxide, ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, Alternatively, a polyol obtained by adding an alkylene oxide such as polyoxytetramethylene oxide; and the like can be mentioned.

Examples of the compound having two or more active hydrogen groups include low molecular weight polyols, aliphatic amine compounds, aromatic amine compounds, alkanolamines and bisphenols.

Examples of the low molecular weight polyol include bifunctional low molecular weight polyols and trifunctional or higher functional low molecular weight polyols.

The bifunctional low molecular weight polyol is not particularly limited, and is, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4. -Butanediol, neopentyl glycol, pentandiol, hexanediol, octanediol, nonanediol, dipropylene glycol, diethylene glycol, triethylene glycol, 3-methyl-1,5-pentanediol, 2-butyl-2-ethyl-1 , 3-Propanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, polyoxyethylene glycol (additional moles: 10 or less), polyoxypropylene glycol (additional moles: 10 or less) ), Cyclohexanediol, Cyclohexanedimethanol, Tricyclodecanedimethanol, Cyclopentadienedimethanol, Dimerdiol, Bisphenol A, N, N-bis (2-hydroxypropyl) aniline, Dimethylolacetic acid, Dimethylolpropionic acid, Dimethylolbutane Acids, 2,2-dimethylolbutyric acid, 2,2-dimethylolpentanoic acid, dihydroxysuccinic acid, dihydroxypropionic acid, dihydroxybenzoic acid and the like can be mentioned.

The trifunctional or higher functional low molecular weight polyol is not particularly limited, and is, for example, trimethylolethane, trimethylolpropane, 1,1,1-trimethylolbutane, 1,2,3-butanetriol, 1,2,4-. Butantriol, 1,2,6-butanetriol, trimethylolpropane, trimethylolpentene, trimethylolhexene, trimethylolhepten, trimethylolocten, trimethylolnonen, trimethylolpropane, trimethylolpropane, trimethylolpropane , Trimethyloltrydecene, trimethylolpentadecene, trimethylolhexadecene, trimethylolheptadecene, trimethyloloctadecene, 1,1,1-trimethylol-2-methyl-hexane, 1,1,1-trimethylol-3 -Methyl-hexane, 1,1,1-trimethylol-2-ethyl-hexane, 1,1,1-trimethylol-3-ethyl-hexane, trimethylolhexene, 1,2,3-octanetriol, 1, 3,7-octanetriol, 3,7-dimethyl-1,2,3-octanetriol, 1,1,1-, 1,1,1-trimethylolpropane, 1,2,10-decantryol, 1, 1,1-Trimethylolisoheptadecane, 1,1,1-trimethylol-sec-butane, 1,1,1-trimethylol-tert-pentane, 1,1,1-trimethylol-tert-nonan, 1 , 1,1-trimethylol-tert-tridecane, 1,1,1-trimethylol-tert-heptadecane, 1,1,1-trimethylol-2-methyl-hexane, 1,1,1-trimethylol-3 -Methyl-hexane, 1,1,1-trimethylol-2-ethyl-hexane, 1,1,1-trimethylol-3-ethyl-hexane, 1,1,1-trimethylolisoheptadecane, 1,2 , 3,4-Butanetetraol, pentaerythritol, dipentaerythritol, tripentaerythritol, glycerin, diglycerin, triglycerin, polyglycerin, trimethylolethane, dimethylolpropane, tris (2-hydroxyethyl) isocyanurate, benzene -1,3,5-triol, benzene-1,2,3-triol, stilben-3,4', 5-triol, shoe claus, inositol, sorbitan, sorbitol, mannitol, saccharose, cellulose, xylyl Thor can be mentioned.

Examples of the aliphatic amine compounds include ethylenediamine, triethylenetetramine, diethylenetriamine, and triaminopropane. Examples of aromatic amine compounds include toluenediamine and diphenylmethane-4,4-diamine. Examples of alkanolamines include ethanolamine and diethanolamine. Examples of bisphenols include bisphenol A, bisphenol AP, bisphenol B, bisphenol C, bisphenol E, and bisphenol F.

(Polyester polyol)
Examples of the polyester polyol include the polyester polyol in which the above-mentioned low molecular weight polyol and the dibasic acid component are condensed and reacted.
Dibasic acid components include terephthalic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, hydrogenated dimer acid, phthalic anhydride, isophthalic acid, trimellitic acid, glutaric acid, pimeric acid, suberic acid, sebacic acid, etc. The aliphatic or aromatic dibasic acids of the above, and their anhydrides are mentioned.

Further, as the polyester polyol, a polyester polyol obtained by ring-opening polymerization of a cyclic ester compound of lactones such as ε-caprolactone, poly (β-methyl-γ-valerolactone) and polyvalerolactone may be used.

(Polycarbonate polyol)
Examples of the polycarbonate polyol include those obtained by reacting the above-mentioned low molecular weight polyol with a carbonate compound such as a dialkyl carbonate, an alkylene carbonate, or a diaryl carbonate.
As the dialkyl carbonate, dimethyl carbonate or diethyl carbonate or the like can be used, as the alkylene carbonate, ethylene carbonate or the like can be used, and as the diaryl carbonate, diphenyl carbonate or the like can be used.

(Polyolefin polyol)
Examples of the polyolefin polyol include hydroxyl group-containing polybutadiene, hydrogenated hydroxyl group-containing polybutadiene, hydroxyl group-containing polyisoprene, hydrogenated hydroxyl group-containing polyisoprene, hydroxyl group-containing chlorinated polypropylene, and hydroxyl group-containing chlorinated polyethylene.

(Vegetable oil-based polyol)
Examples of the vegetable oil-based polyol include castor oil derived from plants, dimer acid, and polyols made from soybean oil.

The polyol is preferably a polyether polyol, a polyester polyol, a polyolefin polyol or a polycarbonate polyol, and more preferably a polyether polyol.

The number average molecular weight of the polyol is preferably 500 or more and less than 5,000, and more preferably 700 or more and less than 3,500.

The polyol may contain other polyols other than the above, and the above-mentioned low molecular weight polyols can be used in combination for the purpose of adjusting the urethane bond concentration and introducing various functional groups.

<Polyisocyanate>
Examples of the polyisocyanate constituting the urethane unit (A) include aromatic, aliphatic or alicyclic diisocyanates. These may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the aromatic diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylenedi isocyanate, p-phenylenedi isocyanate, 4,4'-diphenylmethane diisocyanate, and 2,4-diphenylmethane diisocyanate, 2 , 2'-Diphenylmethane diisocyanate, 1,5-naphthalenediisocyanate, trizine diisocyanate, xylylene diisocyanate, m-tetramethylxylene diisocyanate, p-tetramethylxylene diisocyanate, 3,3'-dimethyl-4 , 4'-biphenylenediocyanate, 3,3'-dimethoxy-4,4'-biphenylenediocyanate, 3,3'-dichloro-4,4'-biphenylenediocyanate, 1,5-tetrahydronaphthalenediisocyanate.

Examples of the aliphatic diisocyanis include trimethylene diisocyanis, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanis, 2,3-butylenedisocyanate, 1,3-butylenedisisocyanis, dodecamethylene diisocyanis, and 2). , 4,4-trimethylhexamethylene diisocyanate, lysine diisocyanis, lysine ester triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate tetramethylene diisocyanate, pentamethylene diisocyanis, trimethylhexamethylene Diisocyanate can be mentioned.

Examples of the alicyclic diisocyanate include isophorone diisocyanate, 1,3-cyclopentane diisocyanate, 1,3-cyclohexanediisocyanate, 1,4-cyclohexanediisocyanate, methyl-2,4-cyclohexanediisocyanate, and methyl-2,6-cyclohexane. Examples thereof include diisocyanate, 4,4'-methylenebis (cyclohexylisocyanate), 1,4-bis (isocyanatemethyl) cyclohexane, hydrogenated xylylene diisocyanate, diisocyanate dimerate, and norbornene diisocyanate.

The reaction between the polyol and the polyisocyanate can be preferably carried out using a known urethanization reaction in the absence of a solvent, and by adding an excess of the polyisocyanate, a urethane unit having isocyanate groups at both ends can be obtained. it can. The molar ratio of isocyanate groups to hydroxyl groups during the reaction (number of moles of NCO / number of moles of OH) is preferably 1.05 to 2.00, more preferably 1.10 to 1.50.
In the urethanization reaction, a catalyst may be used for the purpose of adjusting the reactivity.

(catalyst)
As the catalyst, known metal-based catalysts, amine-based catalysts and the like can be used. Metallic catalysts include dibutyltin dilaurate, tin octoate, dibutyltin di (2-ethylhexoate), lead 2-ethylhexoate, 2-ethylhexyl titanate, titanium ethylacetate, 2-ethylhexoate. Examples thereof include iron, 2-ethylhexoate cobalt, zinc naphthenate, cobalt naphthenate, tetra-n-butyltin and the like. Examples of the amine-based catalyst include tertiary amines such as tetramethylbutanediamine. The amount of the catalyst used is preferably in the range of 0.05 to 1 mol% with respect to the polyol.

(Content of urethane unit (A))
The content of the urethane unit (A) is preferably 25 to 90 parts by mass, more preferably 45 to 90 parts by mass, and further preferably 60 to 85 parts by mass when the urethane / acrylic composite resin is 100 parts by mass. Is. When the content of the urethane unit (A) is 25 to 90 parts by mass, it is preferable because it is excellent in adhesive strength, flexibility, and adhesion.

<Chain transfer agent>
By reacting the urethane unit (A) and the chain transfer agent obtained above in the presence of the reactive diluent (E), the urethane prepolymer having the chain transfer agent residues at both ends and the reactive dilution A composition containing the agent (E) can be obtained. The chain transfer agent is not particularly limited, but preferably has a functional group capable of reacting with an isocyanate group and a sulfanil group. When the chain transfer agent is used, the terminal isocyanate group in the urethane unit (A) reacts with the functional group capable of reacting with the isocyanate group in the chain transfer agent to form a urethane prepolymer having sulfanyl groups at both ends. .. The chain transfer agent can be used alone or in combination of two or more from known chain transfer agents.

Examples of the functional group capable of reacting with the isocyanate group include a hydroxyl group or an amino group, and an amino group is preferable from the viewpoint of reactivity. Since the amino group is more reactive than the sulfanyl group, it preferentially reacts with the terminal isocyanate group of the urethane unit to form a urea bond, and the sulfanyl group can be efficiently introduced into the terminal of the urethane prepolymer.
The hydroxyl group in the reactive diluent described later may also react with the terminal isocyanate group of the urethane unit, but by using a chain transfer agent having an amino group that is more reactive than the hydroxyl group, a bifunctional or higher functional polyol can be obtained. It is preferable because the reaction of the urethane unit with the isocyanate group is suppressed and the sulfanyl group can be efficiently introduced into the terminal of the urethane prepolymer.

Examples of compounds having one amino group and one sulfanyl group in the molecule include 2-aminoethanethiol, 3-aminopropyl-1-thiol, 1-aminopropyl-2-thiol, 4-amino-1-. Examples thereof include aminoalkanethiols such as butanethiol; aminobenzenethiols such as 2-aminothiophenol, 3-aminothiophenol, and 4-aminothiophenol; Among them, aminoalkanethiols are preferable, and 2-aminoethanethiol is more preferable.

<Reactive diluent (E)>
The reactive diluent (E) may be a liquid substance having reactivity with the cross-linking agent (D) described later, and is preferably a compound having a bifunctional or higher functional hydroxyl group. When the adhesive composition contains the reactive diluent (E), the film formed by the composition becomes more strongly cured, and excellent adhesive strength can be obtained.
As the reactive diluent (E), for example, in addition to the various polyols mentioned in the above section of polyols, low molecular weight polyols used as raw materials thereof can be used. One of these may be used alone, or two or more thereof may be used. It is preferably a polyether polyol, more preferably polypropylene glycol and polyethylene glycol.
As described above, it is preferable that the urethane prepolymer in step 2 is mainly composed of the reaction product of the urethane unit and the chain transfer agent, and most of the reactive diluent remains unreacted.

The number average molecular weight of the reactive diluent (E) is preferably 100 to 5,000, more preferably 150 to 2,000, and even more preferably 200 to 1,200.
The hydroxyl value of the bifunctional or higher functional polyol is preferably 10 to 1000 mgKOH / g, more preferably 40 to 750 mgKOH / g, and even more preferably 150 to 600 mgKOH / g.
It is preferable that the number average molecular weight and the hydroxyl value are within the above ranges because they are excellent in adhesive strength, flexibility, and substrate adhesion.

<(Meta) Acryloyl unit (B)>
The (meth) acryloyl unit (B) is an ethylenically unsaturated monomer having a structural unit derived from a (meth) acrylic monomer (b1) having a hydroxyl group in the molecule and one or more ketone groups in the molecule. Ethylene having a structural unit derived from (b2) and having a (meth) acrylic monomer (b1) having a hydroxyl group and at least one group selected from the group consisting of a ketone group and an aldehyde group in the molecule. It is a structure obtained by polymerizing an ethylenically unsaturated monomer containing a sex unsaturated monomer (b2) in the presence of a polymerization initiator.
Specifically, a composition containing a urethane prepolymer having chain transfer agent residues at both ends obtained in step 2 and a reactive diluent (E), and a (meth) acrylic single amount having a hydroxyl group in the molecule. Polymerization of the body (b1) and an ethylenically unsaturated monomer containing an ethylenically unsaturated monomer (b2) having at least one group selected from the group consisting of a ketone group and an aldehyde group in the molecule are started. A urethane-acrylic composite resin (C) in which a urethane unit (A) and a (meth) acryloyl unit (B) are linked by a chain transfer agent residue by polymerizing in the presence of an agent, and a reactive diluent. A resin composition containing (E) can be obtained.

((Meta) acrylic monomer having a hydroxyl group (b1))
The (meth) acrylic monomer having a hydroxyl group is not particularly limited, and is, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl ( Caprolactone of 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2-hydroxy-3-allyloxypropyl (meth) acrylate, 2- (meth) acryloyloxyethyl-2-hydroxypropylphthalate or these monomers Additives (additional moles 1 to 5), polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, glycerin mono (meth) acrylate, N- (2-hydroxyethyl) (meth) acrylamide, N-methylol ( Examples thereof include meta) acrylamide, N, N-di (methylol) acrylamide, and N-methylol-N-methoxymethyl (meth) acrylamide. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The content of the structural unit derived from the (meth) acrylic monomer (b1) having a hydroxyl group is preferably 5 to 95 parts by mass, more preferably 10 to 10 parts by mass, based on 100 parts by mass of the (meth) acryloyl unit (B). It is 80 parts by mass, more preferably 15 to 60 parts by mass. When the content is 5 to 95 parts by mass, it is preferable because it is excellent in adhesive strength, flexibility, and adhesion.

(Ethylene unsaturated monomer (b2) having at least one group selected from the group consisting of a ketone group and an aldehyde group in the molecule)

The ethylenically unsaturated monomer (b2) having at least one group selected from the group consisting of a ketone group and an aldehyde group in the molecule is not particularly limited, and can be appropriately selected from known monomers. These may be used individually by 1 type, and may be used in combination of 2 or more type.
Examples of ethylenically unsaturated monomers having one or more aldehyde groups in the molecule include acrolein, N-vinylformamide, formylstyrene, (meth) acrylamide pivalinaldehyde, butanediol-1,4-acrylate-acetyl. Examples include acetate, acrylamide methylanisaldehyde, and methacrylformamide.
Examples of the ethylenically unsaturated monomer having one or more ketone groups in the molecule include diacetone (meth) acrylamide, N-vinylacetamide, vinylmethylketone, vinylethylketone, and acetoxyethyl (meth) acrylate. Cyanacetoxyethyl (meth) acrylate, N- (cyanoacetoxyethyl) acrylamide, N- (propionylacetoxybutyl) acrylamide, N- (4-acetacetoxymethylbenzyl) acrylamide, N- (2-acetoacetylaminoethyl) acrylamide Can be mentioned.

Among them, the ethylenically unsaturated monomer (b2) preferably has two or more ketone groups, and more preferably has a β-diketone structure.
Examples of the ethylenically unsaturated monomer having a β-diketone structure include acetoacetoxymethyl (meth) acrylate, acetoacetoxyethyl (meth) acrylate, acetoacetoxypropyl (meth) acrylate, and acetoacetoxybutyl (meth) acrylate. Examples thereof include 2-acetoacetoxy-1-methylethyl (meth) acrylate and 2-ethoxymalonyloxyethyl (meth) acrylate.

The content of the structural unit derived from the ethylenically unsaturated monomer (b2) is preferably 5 to 95 parts by mass, more preferably 5 to 60 parts by mass, out of 100 parts by mass of the (meth) acryloyl unit (B). It is more preferably 5 to 30 parts by mass. When the content is 5 to 95 parts by mass, it is preferable because it is excellent in adhesive strength, flexibility, and adhesion.

(Other ethylenically unsaturated monomers)
Examples of other ethylenically unsaturated monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth). Acrylate, tertiary butyl (meth) acrylate, isoamyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, cetyl (meth) acrylate, decyl (meth) acrylate, isodecyl ( Linear or branched alkylethylenic unsaturated monomers such as meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, isomyristyl (meth) acrylate, stearyl (meth) acrylate, and isostearyl (meth) acrylate. Cyclohexyl (meth) acrylate, tertiarybutylcyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentanyloxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl ( Cyclic alkyl (meth) acrylates such as meta) acrylates and isobornyl (meth) acrylates; trifluoroethyl (meth) acrylates, octafluoropentyl (meth) acrylates, perfluorooctylethyl (meth) acrylates, tetrafluoropropyl (meth) Fluoroalkyl ethylenically unsaturated monomers such as acrylates; Ethylene unsaturated monomers having a heterocycle such as tetrahydrofurfuryl (meth) acrylates and 3-methyl-3-oxetanyl (meth) acrylates; benzyl ( Fragrances such as meta) acrylate, phenoxyethyl (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, paracumylphenoxyethyl (meth) acrylate, paracumylphenoxypolyethylene glycol (meth) acrylate, or nonylphenoxypolyethylene glycol (meth) acrylate. (Meta) acrylates having a group ring; methoxypolyethylene glycol mono (meth) acrylate, octoxypolyethylene glycol polypropylene glycol mono (meth) acrylate, lauroxypolyethylene glycol mono (meth) acrylate, stearoxypolyethylene glycol mono (meth) acrylice Oxetane, phenoxypolyethylene glycol mono (meth) acrylate, phenoxypolyethylene glycol polypropylene glycol mono (meth) acrylate, polyethylene glycol monomethyl ether (meth) acrylate, lauroxypolyethylene glycol mono (meth) acrylate, nonylphenoxypolyethylene glycol mono (meth) Acrylic, nonylphenoxypolypolyglycol mono (meth) acrylate, nonylphenoxypolyethylene glycol polypropylene glycol mono (meth) acrylate, phenoxypolyethylene glycol mono (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, n-butoxyethyl (meth) acrylate, Ethylene unsaturated monomers having an alkyl ether group such as n-butoxydiethylene glycol (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate; 3- (acryloyloxymethyl) 3 -Methyloxetane, 3- (methacryloyloxymethyl) 3-methyloxetane, 3- (acryloyloxymethyl) 3-ethyloxetane, 3- (methacryloyloxymethyl) 3-ethyloxetane, 3- (acryloyloxymethyl) 3-butyl Ethylene unsaturated monomer having an oxetane group such as oxetane, 3- (methacryloyloxymethyl) 3-butyloxetane, 3- (acryloyloxymethyl) 3-hexyloxetane and 3- (methacryloyloxymethyl) 3-hexyloxetane Classes; ethylenically unsaturated monomers having a vinyl group such as styrene, α-methylstyrene, vinyl acetate, vinyl (meth) acrylate, or allyl (meth) acrylate; ethyl vinyl ether, n-propyl vinyl ether, isopropyl Ethylene unsaturated monomers having an ether group such as vinyl ether, n-butyl vinyl ether, or isobutyl vinyl ether; glycidyl (meth) acrylic acid, (meth) acrylic acid-3,4-epoxybutyl, (meth) acrylic acid -4,5-epoxypentyl, (meth) acrylic acid-6,7-epoxypentyl, (meth) acrylic acid-3,4-epoxycyclohexyl, lactone-modified (meth) acrylic acid-3,4-epoxycyclohexyl, vinyl Ethylene unsaturated monomers having an epoxy group such as cyclohexene oxide; a Minoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dibutylaminoethyl (meth) acrylate, dipropylaminoethyl (meth) acrylate, t-butylaminoethyl methacrylate, methylethylaminoethyl ( Meta) acrylate, N-aminoethyl (meth) acrylamide, (meth) allylamine, morpholinoethyl (meth) acrylate, 4-vinylpyridine, 2-vinylpyridine, crotylamine, N, N-dimethylaminostyrene, N, N-diethylamino Amino group-containing ethylenically unsaturated monomers such as styrene, methyl α-acetoaminoacrylate, vinyl imidazole, N-vinylthiopyrrolidone, N-vinylpyrrole, etc .; (meth) acrylonitrile, cyanostyrene, cyanoacrylate, nitro Ethyl unsaturated monomers containing cyano groups such as styrene; (meth) acrylamide, N-methyl (meth) acrylamide, N-butyl acrylamide, N-terrary-octyl acrylamide, N-methoxymethyl- (meth) acrylamide, N-ethoxymethyl- (meth) acrylamide, N-propoxymethyl- (meth) acrylamide, N-butoxymethyl- (meth) acrylamide, N-isobutoxymethyl- (meth) acrylamide, N-tershaly butoxymethyl- (meth) ) Ethyl, N-pentoxymethyl- (meth) acrylamide, N, N-dimethylacrylamide, N, N-dibenzylacrylamide, N-methyl N-vinylacetamide, N-vinylpyrrolidone, N, N-di (methoxymethyl) ) Ethyl, N-ethoxymethyl-N-methoxymethyl metaacrylamide, N, N-di (ethoxymethyl) acrylamide, N-ethoxymethyl-N-propoxymethyl metaacrylamide, N, N-di (propoxymethyl) acrylamide, N -Butoxymethyl-N- (propoxymethyl) metaacrylamide, N, N-di (butoxymethyl) acrylamide, N-butoxymethyl-N- (methoxymethyl) metaacrylamide, N, N-di (pentoxymethyl) acrylamide, Amid group-containing ethylenically unsaturated monomers such as N-methoxymethyl-N- (pentoxymethyl) metaacrylamide and cinnamic acid amide; trimethylammonioethyl (meth) acrylate chloride, methyldier Contains quaternary ammonium cations such as tylammonioethyl (meth) acrylate bromide, trimethylammonioethyl (meth) acrylamide metsulfate, benzyldiethylammonioethyl (meth) acrylamide carbonate, dimethyldialylammonium chloride, and trimethylallylammonium chloride. Ethylylated unsaturated monomers; (meth) acrylic acid, itaconic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyhexa Examples thereof include carboxy group-containing ethylenically unsaturated monomers such as hydrophthalic acid.
These may be used individually by 1 type, and may be used in combination of 2 or more type.

<Polymerization initiator>
As the polymerization initiator, known azo compounds and organic peroxides can be used. These may be used individually by 1 type, and may be used in combination of 2 or more type.
The azo compound is not particularly limited, and is, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), 1,1'-azobis (cyclohexane1-cyclohexane1-). Carbonitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), 2,2'-azobis (4-methoxy) -2,4-dimethylvaleronitrile), dimethyl 1,1'-azobis (1-cyclohexanecarboxylate), dimethyl 2,2'-azobis (2-methylpropionate), 4,4'-azobis (4) -Cyanovaleric acid), 2,2'-azobis (2-hydroxymethylpropionitrile), or 2,2'-azobis [2- (2-imidazolin-2-yl) propane].
The organic peroxide is not particularly limited, and is, for example, benzoyl peroxide, t-butylperoxy2-ethylhexaate, t-butylperbenzoate, cumenehydroperoxide, diisopropylperoxydicarbonate, di-n. -Propyl peroxydicarbonate, di (2-ethoxyethyl) peroxydicarbonate, t-butylperoxyneodecanoate, t-butylperoxyvivarate, (3,5,5-trimethylhexanoyl) peroxide, Examples thereof include dipropionyl peroxide and diacetyl peroxide.

The amount of the polymerization initiator used is preferably 0.001 to 15 parts by mass with respect to 100 parts by mass of the total ethylenically unsaturated monomer. A range of 0.001 to 15 parts by mass is preferable because chain transfer polymerization effectively proceeds.

(Number average molecular weight of urethane / acrylic composite resin (C))
The number average molecular weight of the urethane-acrylic composite resin (C) is not particularly limited, but is preferably 7,000 to 100,000, more preferably 8,000 to 70,000, and even more preferably 9,000 to 9000. It is 50,000. A value of 7,000 to 100,000 is preferable because it is excellent in adhesive strength, flexibility, and adhesion.

(Hydroxyl value of urethane / acrylic composite resin (C))
The hydroxyl value of the urethane-acrylic composite resin (C) is preferably 1 to 400 mgKOH / g, more preferably 1 to 250 mgKOH / g, and even more preferably 5 to 100 mgKOH / g. When it is 1 to 400 mgKOH / g

<Solvent>
Examples of the solvent that can be used in producing the urethane / acrylic composite resin (C) include ethers such as dibutyl ether, dimethoxymethane, dimethoxyethane, propylene oxide, 1,3-dioxolane, 1,4-dioxane, and tetrahydrofuran. Esters such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, as well as toluene, methylcyclohexane and acetonitrile. These solvents may be used alone or in combination of two or more. The solvent used in the present invention is preferably removed under reduced pressure or normal pressure in the middle of the reaction or after the reaction is completed.

<Adhesive composition>
The adhesive composition of the present invention further contains a cross-linking agent (D).

<Crosslinking agent (D)>
The cross-linking agent (D) preferably has a functional group capable of reacting with the functional group of the urethane-acrylic composite resin or the reactive diluent contained in the adhesive composition, and is preferably polyisocyanate. Examples of the polyisocyanate include compounds having two or more isocyanate groups in the molecule, and biuret-forms, nurate-forms, adduct-forms, and other condensates thereof. As the cross-linking agent, one type may be used alone, or two or more types may be used in combination.

Examples of the biuret body include a hexamethylene diisocyanate biuret body (product name "Sumijour N-75", manufactured by Sumika Bayer Urethane Co., Ltd .; product name "Duranate 24A-100", manufactured by Asahi Kasei Chemicals Co., Ltd.).

Examples of the nurate form include a hexamethylene diisocyanate nurate form (product name "Sumijour N-3300", manufactured by Sumika Bayer Urethane Co., Ltd.) and an isophorone diisocyanate nurate form (product name "Death Module Z-4370", Sumika). Bayer Urethane Co., Ltd.), tolylene diisocyanate nurate (product name "Coronate 2030", manufactured by Nippon Polyurethane Industry Co., Ltd.) and the like.

As the adduct body, the aromatic, aliphatic or alicyclic diisocyanate described in the above-mentioned urethane unit section is reacted with the compound having two or more active hydrogen groups described in the above-mentioned polyol section. Examples of bifunctional or higher functional isocyanate compounds include hexamethylene diisocyanate adducts of trimethylolpropane (product name "Takenate D-160N", manufactured by Mitsui Chemicals, Inc.) and isophorone diisocyanate adducts of trimethylolpropane (products). Name "Takenate D-140N", manufactured by Mitsui Chemicals, Inc.), trimethylolpropane adduct compound of tolylene diisocyanate can be mentioned.

Examples of other condensates include polyfunctionals of the above-mentioned isocyanate group-containing compounds, carbodiimide-modified products, biuret-modified products, and allophanate-modified products. For example, polymethylene polyphenyl polyisocyanate (product name "PAPI27", Dow Co., Ltd.) , Hexamethylene diisocyanate biuret (product name "Takenate D-165N", manufactured by Mitsui Chemicals, Inc.), carbodiimide-modified diphenylmethane diisocyanate (product name "Isonate 143L", manufactured by Dow Co., Ltd.).

Among them, preferably as a cross-linking agent, a biuret form of hexamethylene diisocyanate, an isocyanurate form of hexamethylene diisocyanate, a trimethylolpropane adduct form of tolylene diisocyanate, a polymethylene polyphenyl polyisocyanate, a trimethylolpropane adduct form of xylylene diisocyanate, etc. It is a trifunctional isocyanate compound, diphenylmethane diisocyanate, or tolylene diisocyanate, and it is preferable to use these because high cohesive force can be obtained. More preferably, it is an isocyanurate form of hexamethylene diisocyanate, a trimethylolpropane adduct form of tolylene diisocyanate, polymethylene polyphenyl polyisocyanate, or diphenylmethane diisocyanate.

The molar ratio of the isocyanate groups in the cross-linking agent (D) to all the hydroxyl groups contained in the adhesive composition (number of moles of isocyanate groups / number of moles of hydroxyl groups) is preferably 0.2 to 5.0. More preferably, it is 0.5 to 3.0. A molar ratio of 0.2 to 5.0 is preferable because it is excellent in adhesive strength, flexibility, and adhesion.

<Other ingredients>
The adhesive composition further comprises a reaction accelerator, a silane coupling agent, a phosphoric acid or a phosphoric acid derivative, a leveling agent or an antifoaming agent, a filler, a propellant, a plasticizer, a superplasticizer, a wetting agent, a flame retardant, etc. Known additives such as viscosity modifiers, preservatives, stabilizers and colorants can be included.

Examples of the reaction accelerator include metal catalysts such as dibutyltin diacetate, dibutyltin dilaurate, dioctyltin dilaurate, and dibutyltin dimalate; 1,8-diazabicyclo (5,4,0) undecene-7,1,5. Tertiary amines such as −diazabicyclo (4,3,0) nonene-5,6-dibutylamino-1,8-diazabicyclo (5,4,0) undecene-7; reactive tertiary amines such as triethanolamine Can be mentioned. These may be used individually by 1 type, and may be used in combination of 2 or more type.

The amount of the reaction accelerator added is preferably 0.005 to 5 parts by mass with respect to 100 parts by mass of the urethane-acrylic composite resin in the adhesive composition.

Examples of the silane coupling agent include trialkoxysilane having a vinyl group such as vinyltrimethoxysilane and vinyltriethoxysilane, 3-aminopropyltriethoxysilane, and N- (2-aminoethyl) 3-aminopropyltrimethoxy. Trialkoxysilane having an amino group such as silane; glycidyl group such as 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane Examples thereof include trialkoxysilanes having an isocyanate group such as 3-isocyanatepropyltriethoxysilane; and trialkoxysilanes having a mercapto group such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoxysilane. .. These may be used alone or in combination of two or more.

The amount of the silane coupling agent added is preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the urethane-acrylic composite resin in the adhesive composition.

Among the phosphoric acid or phosphoric acid derivatives, the phosphoric acid may be any phosphoric acid having at least one free oxygen acid, for example, hypophosphoric acid, phosphoric acid, orthophosphoric acid, hypophosphoric acid and the like. Phosphoric acids, metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, ultraphosphoric acid and other condensed phosphoric acids can be mentioned. Examples of the phosphoric acid derivative include those in which the above-mentioned phosphoric acid is partially esterified with alcohols while leaving at least one free oxygen acid. Examples of these alcohols include fatty alcohols such as methanol, ethanol, ethylene glycol and glycerin, and aromatic alcohols such as phenol, xylenol, hydroquinone, catechol and fluoroglycinol. One type of phosphoric acid or a derivative thereof may be used alone, or two or more types may be used in combination.

The amount of phosphoric acid or a derivative thereof added is preferably 0.005 to 5 parts by mass with respect to 100 parts by mass of the urethane-acrylic composite resin in the adhesive composition.

Among the leveling agents or defoaming agents, examples of the leveling agent include polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane, polyester-modified hydroxyl group-containing polydimethylsiloxane, and polyether ester-modified hydroxyl group. Examples thereof include polydimethylsiloxane, acrylic copolymer, methacrylic copolymer, polyether-modified polymethylalkylsiloxane, acrylic acid alkyl ester copolymer, methacrylic acid alkyl ester copolymer, and lecithin.

Examples of the defoaming agent include known ones such as a silicone resin, a silicone solution, and a copolymer of an alkyl vinyl ether, an acrylic acid alkyl ester, and a methacrylic acid alkyl ester.

<Laminated body>
The laminate of the present invention is formed by using the adhesive composition of the present invention. The method for producing the laminate is not particularly limited, and for example, the adhesive composition is applied to one surface of the base material, and then the other base material is superposed on the uncured adhesive surface at about 20 to 150 ° C. A laminate can be obtained by curing the adhesive by heat treatment. The film thickness of the adhesive layer after curing is preferably 0.1 μm to 300 mm.

The adhesive composition of the present invention can be used for adhesion between various base materials. Suitable substrates include, for example, metals such as aluminum, thermoplastic polymers such as polyethylene, polylopylene, polyurethane, polyacrylate and polycarbonate and copolymers thereof, thermosetting polymers such as vulture rubber, urea-formaldehyde foam, melamine. Resins, woods, carbon fiber reinforced plastics, glass fiber reinforced plastics and other fiber reinforced plastics can be mentioned, and the base materials bonded via the adhesive layer may be the same or different.

The laminate of the present invention has excellent adhesive strength, flexibility, and substrate adhesion, and is a structural member (panel part, skeleton part, suspension part) of transportation equipment such as automobiles, building materials, ships, and aircraft. Etc.).

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples do not limit the scope of rights of the present invention at all. Unless otherwise specified, "parts" and "%" in the examples represent "parts by mass" and "% by mass", respectively.

[Number average molecular weight (Mn)]
The number average molecular weight is the polystyrene-equivalent molecular weight when a Shodex GPCLF-604 (manufactured by Shodex) and a GPC (manufactured by Shodex, GPC-104) equipped with an RI detector are used as columns and the developing solvent is THF. Using.

<Manufacturing of urethane / acrylic composite resin>
[Manufacturing Example 1]
100 parts of P-1000 (product name, generic name: bifunctional polypropylene glycol, hydroxyl value 110, manufactured by ADEKA) as a polyol, polyisocyanate in a reaction vessel equipped with a nitrogen gas introduction tube, a stirrer, a thermometer, and a recirculator. 28.3 parts of isophorone diisocyanate and 0.02 parts of titanium diisopropoxybiz (ethylacetoacetate) as a catalyst were charged and stirred uniformly, and then reacted at 110 ° C. for 5 hours in a nitrogen atmosphere to form isocyanate groups at both ends. A urethane unit to have was obtained.
The obtained product was cooled to 80 ° C., and used as a reactive diluent (E) was 70.6 parts of Adeka Polyether G-400 (product name, generic name: trifunctional polypropylene glycol, hydroxyl value 265, manufactured by ADEKA). , 4.3 parts of 2-aminoethanethiol as a chain transfer agent is added and reacted at 75 ° C. for 2 hours to prepare a composition containing a urethane prepolymer having a sulfanyl group at both ends and a reactive diluent (E). Obtained. The end point of the reaction was confirmed by FT-IR by disappearance of the peak derived from the isocyanate group ( ^{around 2270 cm -1).}
In the obtained composition, 6.4 parts of 2-hydroxyethyl methacrylate as the (meth) acrylic monomer (b1) having a hydroxyl group, and at least one group selected from the group consisting of a ketone group and an aldehyde group in the molecule. 6.4 parts of 2-acetoacetoxyethyl methacrylate as an ethylenically unsaturated monomer (b2) having an ethylenically unsaturated monomer (b2) and 19.2 parts of n-butyl methacrylate as another ethylenically unsaturated monomer were added and stirred uniformly. The temperature was raised to 75 ° C. in a nitrogen atmosphere. Next, 0.1 part of 2,2'-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was added in 13 portions every 30 minutes, and the reaction was carried out for another 2 hours after the addition of the polymerization initiator. A (meth) acryloyl unit (B) was formed, and a composition containing a urethane-acrylic composite resin (C-1) and a reactive diluent was obtained.
The content of the urethane unit (A) with respect to the sum of the urethane unit (A) and the (meth) acryloyl unit (B) of the obtained urethane-acrylic composite resin (C-1), in the (meth) acryloyl unit (B). Content of (meth) acrylic monomer (b1) having a hydroxyl group, content of ethylenically unsaturated monomer (b2) in (meth) acryloyl unit (B), urethane-acrylic composite resin (C-1) The number average molecular weight of) is as shown in Table 1.

[Production Examples 2 to 20, Comparative Production Examples 1 and 2]
The same operation as in Production Example 1 was carried out except that the composition was changed to that shown in Table 1, to obtain a composition containing a urethane-acrylic composite resin (C-2 to C-22) and a reactive diluent.

[Comparative Manufacturing Example 3]
The same operation as in Production Example 1 was carried out except that the reactive diluent (E) was not used, to obtain a urethane-acrylic composite resin (C-23) for comparison.

[Comparative Manufacturing Example 4]
100 parts of ADEKApolyether P-1000 (product name, generic name: bifunctional polypropylene glycol, hydroxyl value 110, manufactured by ADEKA), isophorone in a reaction vessel equipped with a nitrogen gas introduction tube, agitator, thermometer, and recirculator. 16.8 parts of diisocyanate and 0.02 part of titanium diisopropoxybiz (ethylacetoacetate) as a reaction accelerator were charged and stirred uniformly, and then reacted at 110 ° C. for 5 hours in a nitrogen atmosphere to have hydroxyl groups at both ends. Obtained a urethane unit.
To the obtained product, 50.0 parts of Adeka Polyether G-400 (product name, generic name: trifunctional polypropylene glycol, hydroxyl value 265, manufactured by ADEKA) was added, and the mixture was sufficiently stirred and mixed for comparison. A composition containing a urethane resin (C-24) and a reactive diluent was obtained.

[Comparative Manufacturing Example 5]
4.3 parts of ADEKApolyether G-400 (product name, generic name: trifunctional polypropylene glycol, hydroxyl value 265, manufactured by ADEKA) in a reaction vessel equipped with a nitrogen gas introduction pipe, a stirrer, a thermometer, and a recirculator. , 2.0 parts of 2-acetoacetoxyethyl methacrylate, 6.0 parts of n-butyl methacrylate and 2.0 parts of 2-hydroxyethyl methacrylate were added and stirred uniformly, and then the temperature was raised to 75 ° C. under a nitrogen atmosphere. Next, 0.1 part of 2,2'-azobis (2,4-dimethylvaleronitrile) as a polymerization initiator was added in 13 portions every 30 minutes, and after all the polymerization initiators were added, the reaction was carried out for another 2 hours. A composition containing a comparative acrylic resin (C-25) and a reactive diluent was obtained.

The abbreviations in Table 1 are shown below.
P-1000; Bifunctional polypropylene glycol, hydroxyl value 110, ADEKA PTG1000SN: Bifunctional polytetramethylene glycol, hydroxyl value 110, Hodoya Chemical Industry IPDI: Isophorone diisocyanate systemamine: 2-aminoethanethiol G-400: Trifunctional polypropylene glycol, hydroxyl value 397, ADEKA HEMA: 2-hydroxyethyl methacrylate HEAA: N- (2-hydroxyethyl) acrylamide AAEM: 2-acetoacetoxyethyl methacrylate DAAM: diacetoneacrylamide BMA: n-butyl methacrylate NIPAM : Isophorone HO-MS (N): 2-Methacryloxyethyl succinic acid

<Preparation of adhesive composition>
[Example 1] Adhesive composition (F-1)
An adhesive composition (F-1) was prepared by stirring and mixing 10 parts of a urethane-acrylic composite resin (C-1) and 4.7 parts of polymethylene polyphenyl polyisocyanate as a cross-linking agent (D) at room temperature.

[Examples 2 to 20 and Comparative Examples 1 to 7]
The same operation as in Example 1 was carried out except that the composition was changed to the composition shown in Table 2, and an adhesive composition (F2 to F-27) was prepared. The adhesive composition (F-24) had a high viscosity and it was difficult to uniformly stir and mix the adhesive composition, so that the adhesive composition could not be obtained.

<Evaluation of adhesive composition>
The obtained adhesive composition was evaluated as follows. The results are shown in Table 2. (F-24) could not be evaluated because an adhesive composition could not be obtained.

[Adhesive strength]
Each adhesive composition is applied onto an aluminum base material (length 100 mm, width 25 mm, thickness 2 mm) so as to have a width of 25 mm, a length of 10 mm, and a thickness of 0.1 mm, and a carbon fiber reinforced plastic base material (length 100 mm). , Width 25 mm, thickness 2 mm), and the adhesive was cured by curing at 80 ° C. for 1 day in a state of being pressure-bonded to maintain the thickness of 0.1 mm to obtain a test piece. The obtained test piece was measured for shear adhesive force using a tensile tester at a tensile speed of 1 mm / min under the conditions of a temperature of 25 ° C. and a relative humidity of 50%, and the adhesive force was judged according to the following evaluation criteria.
(Evaluation criteria)
S: Shear adhesive force is 13.0 MPa or more (very good)
A: Shear adhesive force is 11.5 MPa or more and less than 13.0 MPa (good)
B: Shear adhesive force is 10.0 MPa or more and less than 11.5 MPa (usable)
C: Shear adhesive force is less than 10.0 MPa (cannot be used)

[Fracture elongation (flexibility)]
Each adhesive composition was filled in a sheet-shaped mold having a thickness of 2 mm, the surface was prepared, cured at 80 ° C. for 1 day, and then punched with a dumbbell mold to prepare a dumbbell-shaped cured product. Using this dumbbell piece, a tensile test was conducted at a tensile speed of 50 mm / min, the elongation at break (%) was measured, and the elongation at break (flexibility) was determined according to the following criteria.
(Evaluation criteria)
S: Elongation rate at break is 150% or more (very good)
A: The elongation rate at break is 125% or more and less than 150% (good).
B: Elongation rate at break is 100% or more and less than 125% (usable)
C: Elongation rate at break is less than 100% (cannot be used)

[Adhesion to base material]
For the test piece after evaluating the above-mentioned adhesive strength, the ratio of the area where the cured product of the adhesive composition was peeled off from the base material was observed, and the base material adhesion was judged according to the following criteria. As the peeled area, the area of the base material having the larger peeling was used among the aluminum base material and the carbon fiber reinforced plastic base material.
S: The peeled area is less than 20% (very good)
A: The peeled area is 20% or more and less than 35% (good).
B: The peeled area is 35% or more and less than 50% (usable)
C: The peeled area is 50% or more (cannot be used)

The abbreviations in Table 2 are shown below.
Polymeric MDI: Polymethylene polyphenyl polyisocyanate

From the results shown in Table 2, the adhesive composition of the present invention gave good results in terms of adhesive strength, elongation at break (flexibility), and substrate adhesion. In particular, the content of the structural unit derived from the (meth) acrylic monomer (b1) and the ethylenically unsaturated monomer (b2), the content of the urethane unit (A), and the urethane-acrylic composite resin (C). Examples 1, 4 to 10, 17 and 18, in which the number average molecular weight is within a suitable range and the ethylenically unsaturated monomer (b2) has a β-diketone structure, are excellent in any of the evaluations. The result was.

Claims (7)

Contains a urethane-acrylic composite resin (C), a cross-linking agent (D), and a reactive diluent (E) in which the urethane unit (A) and the (meth) acryloyl unit (B) are linked by a chain transfer agent residue. Adhesive composition
The (meth) acryloyl unit (B) is ethylenically having a structural unit derived from a (meth) acrylic monomer (b1) having a hydroxyl group and at least one group selected from the group consisting of a ketone group and an aldehyde group. An adhesive composition having a structural unit derived from an unsaturated monomer (b2). The adhesive composition according to claim 1, wherein the urethane unit (A) and the (meth) acryloyl unit (B) are linked by a residue of a chain transfer agent having an amino group. In 100 parts by mass of the (meth) acryloyl unit (B), the content of the structural unit derived from the (meth) acrylic monomer (b1) having a hydroxyl group is 15 to 60 parts by mass, and the ketone group and the aldehyde are contained in the molecule. The adhesive according to claim 1 or 2, wherein the content of the structural unit derived from the ethylenically unsaturated monomer (b2) having at least one group selected from the group consisting of groups is 5 to 30 parts by mass. Composition. The adhesive composition according to any one of claims 1 to 3, wherein the content of the urethane unit (A) is 60 to 85 parts by mass in 100 parts by mass of the urethane-acrylic composite resin (C). Claim 1 to any one of claims 1 to 4, wherein the ethylenically unsaturated monomer (b2) having at least one group selected from the group consisting of a ketone group and an aldehyde group in the molecule has a β-diketone structure. The adhesive composition described. The adhesive composition according to any one of claims 1 to 5, wherein the urethane-acrylic composite resin (C) has a number average molecular weight of 9,000 to 50,000. A laminate having an adhesive layer formed from the adhesive composition according to any one of claims 1 to 6 on a base material.