JP5510701B2 - Adhesive composition - Google Patents

Description

  The present invention relates to an adhesive composition that cures by a radical polymerization reaction and exhibits strong adhesive strength.

  Two-component adhesives have high adhesive strength, and the adhesive itself can be designed in a variety of ways from flexible to high-strength, so it can be used in various applications such as sealing materials, general-purpose adhesives, and structural adhesives. It is used.

  As two-component adhesives, polyurethane adhesives with isocyanate prepolymer as the main component and polyether polyol as the curing agent, epoxy resin adhesives with epoxy resin as the main component and polyamine compound, dicyan compound, imidazole, etc. as the curing agent Radical curable adhesives containing acrylic monomers and oligomers are known. A radical-curing type adhesive that can be cured at a low temperature and has a high curing rate has attracted attention.

  As is well known in the industry where polymers are produced by radical polymerization such as acrylic resin, polystyrene resin, unsaturated polyester resin, vinyl ester resin, or curing reaction is carried out, acrylic monomer, unsaturated polyester resin, vinyl When a compound having an acrylic unsaturated double bond, a compound having a vinyl unsaturated double bond, styrene, or the like is contained in a molecule or composition such as an ester resin, these compositions are, for example, peroxidized. When these compositions come into contact with an oxidizing agent such as benzoyl, for example, a reducing agent such as cobalt octylate, radical polymerization is initiated, that is, a curing reaction proceeds, causing a high molecular weight and a three-dimensional crosslinking reaction to cause gelation. It is known to wake up.

  Furthermore, the combination of a strong oxidizing agent and a reducing agent, which is generally well known as a redox curing system, greatly reduces the activation energy related to the initiation reaction of radical polymerization, and the curing reaction can be completed at a low temperature in a short time. well known. In general, methyl ethyl ketone peroxide, benzoyl peroxide, etc. are known as strong oxidizing agents blended in the main agent, and cobalt naphthenate, iron, N, N-dimethylparatoluidine, etc. are blended as reducing agents in the curing agent. well known.

  On the other hand, it is well known that the radical polymerization reaction is easily affected by oxygen, and is practically prohibited from polymerization in the presence of oxygen, or the desired performance cannot be obtained by telomerization. This suggests that, for example, an adhesive is often insufficiently cured at an interface with air, an interface with an adherend, and the like.

  A radical curable adhesive is an adhesive that uses radical polymerization of a vinyl compound that undergoes a curing reaction even at a low temperature and has a high curing rate. Generally, it is divided into a primer type and a two-component mixed type (two-component main agent type, also called SGA (second generation type adhesive)).

  The primer type is a type in which the main agent and the primer (curing accelerator) are separately applied to the adherend. In order to suppress curing failure and prevent peeling at the adherend interface, it is common to apply a thick base agent containing a curing agent and thinly apply a primer containing a curing accelerator. The rate at which the curing accelerator diffuses from the thinly applied primer to the entire adhesive tends to be insufficient, or it is physically impossible to expect the diffusion of the curing accelerator from the primer applied to a thin film. In addition, there is a defect in that insufficient curing and poor curing are caused at the adherend interface, and adhesion failure (interfacial peeling) easily occurs at the adherend interface.

  A technique for improving the coating workability of a two-component mixed type (radical curable adhesive) is disclosed. (See Patent Document 1) A polymer compound having a special structure is added to an adhesive to give thixotropy, thereby improving liquid breakage during coating. Here, as is well known, thixotropic property means that the viscosity changes with respect to the shear rate, and as a phenomenon observed, the viscosity decreases as the shear rate (or shear rate) increases. Even in the proposed technology, thixotropy is evaluated according to JIS. In the proposed technology, thixotropy is high, so when two liquids (main agent, curing agent) are applied separately, that is, sufficient diffusion and mixing of the main agent and curing agent do not occur only by contact of the two components. As a result, there is a concern that poor curing will occur, so the two liquids are mixed before bonding.

  The technique proposed in Patent Document 1 does not consider the curability of the adhesive near the adherend, and the adhesive has high thixotropic properties (that is, a high contact angle to the adherend). In addition, paraffin wax is blended to alleviate the inhibition of curing by oxygen, and the adhesion of the adhesive to the adherend, insufficient wettability, the adherend interface In this case, it is presumed that a large amount of paraffin wax having poor adhesiveness is distributed, and it is presumed that adhesion failure and interfacial peeling are likely to occur due to impact, alternating load or the like.

  The two-component mixed type exhibits good performance, but has a drawback that the pot life is shortened to within a few minutes because the curing is too early and the workability is deteriorated. A technique for solving this is disclosed (see Patent Document 2). The technique proposed in Patent Document 2 uses a curing accelerator having a slightly longer induction period. As can be easily understood from the improvement of pot life, the technique proposed in Patent Document 2 is applied to an adherend after the two main agents are mixed and then bonded.

  In the technique proposed in Patent Document 2, although consideration is given to pot life, no consideration is given to the interface with the adherend, and a specific curing accelerator for extending pot life is an interface. It is feared that insufficient curing and poor curing are likely to occur in the vicinity, and it is presumed that adhesion failure and interfacial peeling are likely to occur due to impact, alternating load, or the like.

  Technology relating to a room temperature fast-curing two-component acrylic composition comprising a main agent to which a radical polymerization initiator is added and a specific polymerization accelerator, that is, a curing agent to which 2-mercaptobenzimidazole and a divalent copper compound are added Has been proposed (see Patent Document 3). According to the proposed technology, the two liquids of the main agent and the curing agent are premised to be mixed immediately before use, but each of the adherends is coated with a curing agent containing the main agent and a specific curing accelerator. It is said that it can be cured just by bonding. Also, the proposed technique has been shown to exhibit a cure reaction rate that exceeds the induction period found in radical polymerization reactions. In this proposal, since the curing speed is abnormally high, it is presumed that the adhesive does not have time to adjust to the adherend, the wetting property to the adherend deteriorates, and the adhesive strength itself decreases.

JP 2005-179548 A JP 2003-221914 A JP 2003-2915 A

  In the present invention, the curing reaction occurs even when the main component and the curing agent of the two-component adhesive are simply mixed, or the main agent and the curing agent are in contact with each other, and the curing reaction proceeds to the deep part of the adhesive, resulting in a strong adhesive force. It is an object to provide an adhesive that develops.

  The present invention relates to (a) a chemical structure (a1) represented by the following structural formula in the molecular main chain:

(Where R1 is a hydrogen atom or a methyl group, R2 is a hydrogen atom, an alkyl group having 2 to 12 carbon atoms, a hydroxyalkyl group having 2 to 6 carbon atoms in the alkyl group, or an alkyl group) (It is a methoxyalkyl group having 2 to 6 carbon atoms, and x represents a mole fraction and is 0.40 to 0.998.)
And a chemical structure (a2) represented by the following structural formula:

(Where R3 represents a hydrogen atom or a methyl group, and W is a chemical structure represented by the following structural formula.

(Here, R4 represents an alkyl group having 2 to 6 carbon atoms, R5 represents an alkyl group having 2 to 4 carbon atoms, and R6 represents a hydrogen atom or a methyl group.)
Or the chemical structure shown by the following structural formula

(Here, R7 represents a hydrogen atom or a methyl group.)
Y represents a mole fraction and is 0.002 to 0.60. )
Including
(B) Poly (meth) acrylic acid alkyl ester branched polymer represented by the following structural formula in the side chain of the molecule

(Here, R8 is a hydrogen atom or a methyl group, R9 is an alkyl group having 1 to 8 carbon atoms, and p represents the degree of polymerization and is an integer of 20 to 500.)
It is a two-component adhesive composition containing an acrylic resin having

  The adhesive composition of the present invention develops a strong adhesive force by proceeding with a curing reaction at a low temperature and in a short time just by applying the adhesive and the adhesive application surface after coating the main agent and the curing agent on the adherend. To do.

  The adhesive composition of the present invention is less susceptible to polymerization inhibition by oxygen and exhibits excellent curing reactivity at a relatively low temperature (room temperature to 60 ° C.).

  In the adhesive composition of the present invention, the curing reaction proceeds to the deep part of the adhesive only by contacting the main agent of the adhesive and the curing agent, that is, the curability is excellent even at the adherend interface, plastic, Strong adhesion is developed regardless of the type of adherend such as metal.

  By using the adhesive composition of the present invention, it becomes possible to separately apply the main agent and the curing agent to the adherend, which has been impossible in the past due to poor deep-curing properties. It is freed from troublesome matters such as mixing with a curing agent, defoaming of entrained foam caused by mixing, and short pot life, and the adhesion workability can be greatly improved.

  The present invention relates to (a) a chemical structure (a1) represented by the following structural formula in the molecular main chain:

(Where R1 is a hydrogen atom or a methyl group, R2 is a hydrogen atom, an alkyl group having 2 to 12 carbon atoms, a hydroxyalkyl group having 2 to 6 carbon atoms in the alkyl group, or an alkyl group) (It is a methoxyalkyl group having 2 to 6 carbon atoms, and x represents a mole fraction and is 0.40 to 0.998.)
And a chemical structure (a2) represented by the following structural formula:

(Where R3 represents a hydrogen atom or a methyl group, and W is a chemical structure represented by the following structural formula.

(Here, R4 represents an alkyl group having 2 to 6 carbon atoms, R5 represents an alkyl group having 2 to 4 carbon atoms, and R6 represents a hydrogen atom or a methyl group.)
Or the chemical structure shown by the following structural formula

(Here, R7 represents a hydrogen atom or a methyl group.)
Y represents a mole fraction and is 0.002 to 0.60. )
Including
(B) Poly (meth) acrylic acid alkyl ester branched polymer represented by the following structural formula in the side chain of the molecule

(Here, R8 is a hydrogen atom or a methyl group, R9 is an alkyl group having 1 to 8 carbon atoms, p represents the degree of polymerization, and is an integer of 20 to 500.)
It is a two-component adhesive composition containing an acrylic resin having

  In the adhesive composition of the present invention, (a) a chemical structure (a1) represented by the following structural formula contained in the molecular main chain:

(Where R1 is a hydrogen atom or a methyl group, R2 is a hydrogen atom, an alkyl group having 2 to 12 carbon atoms, a hydroxyalkyl group having 2 to 6 carbon atoms in the alkyl group, or a carbon atom in the alkyl group) (It is a methoxyalkyl group having 2 to 6 atoms, and x represents a mole fraction and is 0.40 to 0.998.)
The molar fraction x is 0.40 to 0.998, preferably 0.80 to 0.998, and more preferably 0.85 to 0.998. In the adhesive composition of the present invention, the molar fraction x is most preferably 0.90 to 0.995, and a tendency to improve the curability and adhesiveness of the adhesive is observed. In the adhesive composition of the present invention, when the molar fraction x is less than 0.40, the adhesive becomes brittle and adhesive strength is not exhibited. When the molar fraction exceeds 0.998, the curability of the adhesive is deteriorated and the mechanical strength and adhesive strength of the adhesive are not exhibited.

  In the adhesive composition of the present invention, (a) in the chemical structure (a1) contained in the molecular main chain, R2 is preferably a hydrogen atom, an alkyl group having 2 to 8 carbon atoms, or a carbon atom of the alkyl group. A hydroxyalkyl group having 2 to 4 carbon atoms or a methoxyalkyl group having 2 to 4 carbon atoms of the alkyl group;

  In the adhesive composition of the present invention, (a) the chemical structure (a1) represented by the following structural formula contained in the molecular main chain is:

(Where R1 is a hydrogen atom or a methyl group, R2 is a hydrogen atom, an alkyl group having 2 to 12 carbon atoms, a hydroxyalkyl group having 2 to 6 carbon atoms in the alkyl group, or an alkyl group) (It is a methoxyalkyl group having 2 to 6 carbon atoms, and x represents a mole fraction and is 0.40 to 0.998.)
At the time of acrylic resin production, for example, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, tertiary butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, isobornyl acrylate, ethyl methacrylate, methacryl (Meth) acrylic acid alkyl monomers such as n-butyl acid, isobutyl methacrylate, tertiary butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, isobornyl methacrylate, acrylic acid, methacrylic acid, etc. Carboxyl group-containing acrylic monomers, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, methacrylate Hydroxyl group-containing acrylic monomers such as 2-hydroxypropyl phosphate, 4-hydroxybutyl methacrylate, 2-methoxyethyl acrylate, 3-methoxypropyl acrylate, 4-methoxybutyl acrylate, 2-methoxyethyl methacrylate, It can be produced by using an alkoxyalkyl group-containing acrylic monomer such as 3-methoxypropyl methacrylate or 4-methoxybutyl methacrylate. In the adhesive composition of the present invention, these acrylic monomers may be used alone or in a mixture of two or more.

  In the adhesive composition of the present invention, among these acrylic monomers, the number of carbon atoms of an alkyl group such as ethyl acrylate, n-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, or the like is preferable. 2 to 8 (meth) acrylic acid alkyl esters, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxyethyl methacrylate, 4-hydroxybutyl methacrylate and the like have 2 carbon atoms ~ 4 hydroxyl group-containing acrylic monomer, carboxyl group-containing acrylic monomer as methacrylic acid, methoxyalkyl group-containing acrylic monomer as 2-methoxyethyl acrylate having 2 to 4 carbon atoms in alkyl group, etc. Is recommended. In the adhesive composition of the present invention, these acrylic monomers may be used alone or in a mixture of two or more. In the adhesive composition of the present invention, when these acrylic monomers are used, it is easy to produce an acrylic resin, and there is a tendency that an adhesive that is tough and excellent in impact resistance is produced.

  In the adhesive composition of the present invention, in addition to these acrylic monomers, preferably, (meth) acrylic acid alkyl esters such as methyl acrylate, stearyl acrylate, methyl methacrylate, stearyl methacrylate, dicyclopenta Nyl acrylate, dicyclopentenyloxyethyl acrylate, dicyclopentanyl methacrylate, dicyclopentenyloxyethyl methacrylate and other cyclopentadienyl (meth) acrylates, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) Hydroxyl group-containing acrylic monomers such as acrylate, N, N-dimethylaminoethyl acrylate, N, N-diethylaminoethyl acrylate, N, N-dimethylaminoethyl methacrylate, N, N methacrylate Amino group-containing acrylic monomers such as diethylaminoethyl, acrylamide, N, N-dimethylacrylamide, methacrylamide, N, N-dimethylmethacrylamide, amide group-containing acrylic monomers such as diacetone acrylamide, γ-methacryloyloxypropyl An acrylic monomer such as an alkoxysilane group-containing acrylic monomer such as trimethoxysilane or γ-methacryloyloxypropyltriethoxysilane may be used. In the adhesive composition of the present invention, these acrylic monomers may be used alone or in a mixture of two or more.

  In the adhesive composition of the present invention, (a) a chemical structure (a2) represented by the following structural formula in the molecular main chain:

(Where R3 represents a hydrogen atom or a methyl group, and W is a chemical structure represented by the following structural formula.

(Here, R4 represents an alkyl group having 2 to 6 carbon atoms, R5 represents an alkyl group having 2 to 4 carbon atoms, and R6 represents a hydrogen atom or a methyl group.)
Or the chemical structure shown by the following structural formula

(Here, R7 represents a hydrogen atom or a methyl group.)
Y represents a mole fraction and is 0.002 to 0.60. )
Is included.

  In the chemical structure (a2) of the adhesive composition of the present invention, preferably, R4 is an alkyl group having 2 to 4 carbon atoms, and y is 0.005 to 0.10.

  (A) The chemical structure (a2) contained in the molecular main chain is a chemical structure (a2-1) represented by the following structural formula,

(Where R3 is a hydrogen atom or a methyl group, R4 is an alkyl group having 2 to 6 carbon atoms, R5 is an alkyl group having 2 to 4 carbon atoms, R6 is a hydrogen atom or a methyl group, y represents a mole fraction and is 0.002 to 0.60.)
Or a chemical structure represented by the following structural formula (a2-2)

(Here, R3 represents a hydrogen atom or a methyl group, and R7 represents a hydrogen atom or a methyl group.)
It is.

  In the adhesive composition of the present invention, the chemical structure (a2-1) represented by the following structural formula is

(Where R3 is a hydrogen atom or a methyl group, R4 is an alkyl group having 2 to 6 carbon atoms, R5 is an alkyl group having 2 to 4 carbon atoms, R6 is a hydrogen atom or a methyl group, y represents a mole fraction and is 0.002 to 0.60.)
Preferably, an acrylic resin having a hydroxyl group in the molecular side chain, and preferably an isocyanate group-containing acrylic monomer represented by the following structural formula

(Here, R5 represents an alkyl group having 2 to 4 carbon atoms, and R6 represents a hydrogen atom or a methyl group.)
It is manufactured by addition reaction with.

  In the adhesive composition of the present invention, the isocyanate group-containing acrylic monomer preferably used in the present invention is preferably 2-isocyanatoethyl acrylate, 3-isocyanatopropyl acrylate, 4-isocyanatobutyl acrylate, Examples include 2-isocyanatoethyl methacrylate, 3-isocyanatopropyl methacrylate, 4-isocyanatobutyl methacrylate and the like. In the adhesive composition of the present invention, these isocyanate group-containing acrylic monomers may be used alone or in a mixture of two or more.

  In the adhesive composition of the present invention, as the isocyanate group-containing acrylic monomer, for example, “Karenz MOI (2-isocyanatoethyl methacrylate)” (a product of Showa Denko) or the like is arbitrarily used. can do.

  In the adhesive composition of the present invention, the molar fraction y is 0.002 to 0.60, preferably 0.002 to 0.20, and more preferably 0.002 to 0.15. Is desirable. In the adhesive composition of the present invention, when the molar fraction y is less than 0.002, the curability of the adhesive deteriorates, and at the same time, the crosslink density is insufficient, so that the mechanical strength of the adhesive is sufficiently reduced. Adhesive strength is not demonstrated. Even when the molar fraction y exceeds 0.60, the curability of the adhesive is deteriorated, and at the same time, the crosslinking density is insufficient, so that the mechanical strength of the adhesive is lowered and sufficient adhesive strength is not exhibited. In the adhesive composition of the present invention, it is most desirable that the molar fraction y is 0.005 to 0.10, the storage stability and curability of the adhesive are balanced, the mechanical strength is high, and the strong adhesion There is a tendency to exert power.

  Here, in the adhesive composition of the present invention, the molar fraction y is a hydroxyl group content consumed by an addition reaction with an isocyanate group-containing acrylic monomer from the total number of moles of acrylic monomers used in the acrylic resin. When the total number of moles of the acrylic monomer mole number obtained by subtracting the mole number of the acrylic monomer and the isocyanate group-containing acrylic monomer used for the addition reaction is 1.000 moles, It represents the proportion of the isocyanate group-containing acrylic monomer. For example, n-butyl acrylate (molecular weight 128) 81 g / 2-methoxyethyl acrylate (molecular weight 130) 10 g / methacrylic acid 2-hydroxyethyl (molecular weight 130) 7.5 g / methacrylic acid (molecular weight 86) 5 g acrylic resin (molar fraction: n-butyl acrylate 0.806 / acrylic acid 2-methoxyethyl 0.098 / methacrylic acid 2-hydroxyethyl 0.0735 / methacrylic acid 0.022) and methacrylic acid If 2.7 g of 2-isocyanatoethyl (molecular weight 155) (30 mol% of 2-hydroxyethyl methacrylate) is subjected to an addition reaction, the molar fraction of the acrylic resin after the addition reaction is n-butyl acrylate 0.806 / acrylic Acid 2-methoxyethyl 0.098 / methacrylic acid 2-hydroxyethyl 0.051 / methacrylic acid The acid 0.022 / y = 0.022.

  In the adhesive composition of the present invention, (a) the chemical structure (a2-2) represented by the following structural formula contained in the molecular main chain is:

(Here, R3 represents a hydrogen atom or a methyl group, and R7 represents a hydrogen atom or a methyl group.)
Preferably an acrylic resin having a carboxyl group in the molecular side chain, and preferably an epoxy group-containing acrylic monomer represented by the following structural formula

(Here, R7 represents a hydrogen atom or a methyl group.)
It is manufactured by addition reaction with.

  In the adhesive composition of the present invention, examples of the epoxy group-containing acrylic monomer preferably used in the present invention include glycidyl acrylate and glycidyl methacrylate. In the adhesive composition of the present invention, these epoxy group-containing acrylic monomers may be used alone or in a mixture of two or more.

  In the adhesive composition of the present invention, the molar fraction y is desirably 0.002 to 0.60, preferably 0.002 to 0.20, and more preferably 0.002 to 0.15. . In the adhesive composition of the present invention, when the molar fraction y is less than 0.002, the curability of the adhesive deteriorates, and at the same time, the crosslink density is insufficient, so that the mechanical strength of the adhesive is sufficiently reduced. Adhesive strength is not demonstrated. Even when the molar fraction y exceeds 0.60, the curability of the adhesive is deteriorated, and at the same time, the crosslinking density is insufficient, so that the mechanical strength of the adhesive is lowered and sufficient adhesive strength is not exhibited. In the adhesive composition of the present invention, it is most desirable that the molar fraction y is 0.005 to 0.10, the storage stability and curability of the adhesive are balanced, the mechanical strength is high, and the strong adhesion There is a tendency to exert power.

  Here, in the adhesive composition of the present invention, the molar fraction y is a carboxyl epoxy consumed by the addition reaction with the epoxy group-containing acrylic monomer from the total number of moles of the acrylic monomer used in the acrylic resin. When the total number of moles of the acrylic monomer mole number obtained by subtracting the mole number of the group-containing acrylic monomer and the epoxy group-containing acrylic monomer used for the addition reaction is 1.000 moles, It represents the ratio of the epoxy group-containing acrylic monomer to this. For example, acrylics consisting of 82 g of n-butyl acrylate (molecular weight 128), 10 g of 2-methoxyethyl acrylate (molecular weight 130), 5 g of 2-hydroxyethyl methacrylate (molecular weight 130), 3 g of methacrylic acid (molecular weight 86). Resin (molar fraction: n-butyl acrylate 0.810 / 2-methoxyethyl acrylate 0.0972 / methacrylic acid 2-hydroxyethyl 0.0486 / methacrylic acid 0.0441) and glycidyl methacrylate (molecular weight 142) ) 2.5 g (50 mol% of 2-hydroxyethyl methacrylate) is subjected to an addition reaction, the molar fraction of the acrylic resin after the addition reaction is 0.810 n-butyl acrylate / 0.2-methoxyethyl acrylate. 0972 / 2-hydroxyethyl methacrylate 0.0486 / methacrylic acid 0.022 The /z=0.0221.

  In the adhesive composition of the present invention, (a) a chemical structure (a2) represented by the following structural formula contained in the molecular main chain:

(Where R3 represents a hydrogen atom or a methyl group, and W is a chemical structure represented by the following structural formula.

(Here, R4 represents an alkyl group having 2 to 6 carbon atoms, R5 represents an alkyl group having 2 to 4 carbon atoms, and R6 represents a hydrogen atom or a methyl group.)
Or the chemical structure shown by the following structural formula

(Here, R7 represents a hydrogen atom or a methyl group.)
Y represents a mole fraction and is 0.002 to 0.60. )
Among them, the chemical structure (a2-2) represented by the following structural formula

(Here, R3 represents a hydrogen atom or a methyl group, R7 represents a hydrogen atom or a methyl group, and y represents a molar fraction, and is 0.005 to 0.10.)
It is recommended that In the adhesive composition of the present invention, the acrylic resin has a chemical structure (a2-2) represented by the following structural formula in the molecular main chain.

(Here, R3 represents a hydrogen atom or a methyl group, R7 represents a hydrogen atom or a methyl group, and y represents a molar fraction, and is 0.005 to 0.10.)
By having this, the adhesive force to metals, such as aluminum, iron, copper, and a titanium alloy, improves, and the tendency to exhibit strong interface adhesive force and mechanical strength is seen.

  In the adhesive composition of the present invention, the chemical structure (a2) is more preferably a chemical structure represented by the following structural formula:

(Here, y represents a mole fraction and is 0.005 to 0.10.)
It is.

  In the adhesive composition of the present invention, the acrylic resin is a poly (meth) acrylic acid alkyl ester branched polymer represented by the following structural formula in the molecular side chain.

(Here, R8 is a hydrogen atom or a methyl group, R9 is an alkyl group having 1 to 8 carbon atoms, and p represents the degree of polymerization and is an integer of 20 to 500.)
Have

  In the adhesive composition of the present invention, the poly (meth) acrylic acid alkyl ester branch polymer is preferably produced by using a poly (meth) acrylic acid alkyl ester macromonomer, preferably at the time of acrylic resin production. . In the adhesive composition of the present invention, the poly (meth) acrylic acid alkyl ester macromonomer preferably used in the production of the acrylic resin includes a poly (n-butyl acrylate) macromonomer, a polymethyl methacrylate macromonomer, and a polymethacrylic acid n. -A butyl macromonomer etc. are illustrated. In the adhesive composition of the present invention, the (meth) acrylic acid alkyl ester macromonomer preferably used in the present invention may be used alone or in a mixture of two or more. In the adhesive composition of the present invention, in addition to the poly (meth) acrylic acid alkyl ester macromonomer, a polystyrene macromonomer, a polyacrylonitrile macromonomer, or the like may be used in combination for improving the physical properties of the adhesive or compatibilization. it can.

  In the adhesive composition of the present invention, those that are marketed as the poly (meth) acrylic acid alkyl ester macromonomer preferably used in the present invention include “Aron Macromer AA-6” and “Aron Macromer AB-6”. (The above is a product of Toagosei Co., Ltd.). Examples of polystyrene macromonomer that can be used to improve adhesive properties and compatibilization include "Aron Macromer AS-6", and polyacrylonitrile macromonomer "Aron Macromer AN-6" (above, Toagosei products). Is done.

  In the adhesive composition of the present invention, the polymerization degree p of the poly (meth) acrylic acid alkyl ester macromonomer is 20 to 500, preferably 30 to 250, and more preferably 30 to 200. In the adhesive composition of the present invention, when the degree of polymerization p is less than 20, the compatibility between the acrylic resin main chain (matrix) and the side chain (branch) is improved. And permeability are reduced. When the degree of polymerization p exceeds 500, the incompatibility is excessively increased, the thixotropic property of the adhesive becomes too strong, the wettability is deteriorated, and the adhesive force is reduced.

  In the adhesive composition of the present invention, an acrylic resin is a poly (meth) acrylic acid alkyl ester branched polymer whose molecular side chain is represented by the following structural formula:

(Here, R8 is a hydrogen atom or a methyl group, R9 is an alkyl group having 1 to 8 carbon atoms, and p represents the degree of polymerization and is an integer of 20 to 500.)
Have The adhesive composition of the present invention is preferably a two-component adhesive that cures by radical polymerization reaction, and the main agent and the curing agent are mixed even if the main agent and the curing agent are in a rough mixed state. Even if it is only applied to the adherend and the adhesive application surface of the adherend is pasted, that is, the main agent and the curing agent are only in contact with each other, but the adhesive is in contact with the adherend. It cures to the necessary and sufficient state up to the interface, that is, the deep part of the adhesive, and exhibits a strong adhesive force.

  This is because in the adhesive composition of the present invention, since the acrylic resin used in the adhesive of the present invention has a poly (meth) acrylic acid alkyl ester branch polymer in the molecular side chain, the adhesive composition of the present invention. This is presumably because the main agent and the curing agent exhibit functions that are presumed to be self-structuring, transport phenomenon and diffusion behavior, and the diffusion and mixing of the main agent and the curing agent are promoted. As a result, in the adhesive composition of the present invention, even when the main component and the curing agent of the two-component adhesive are separately applied to both the adherends, the diffusion and mixing of the main agent and the curing agent proceed smoothly, and the adhesion The deep-curing property of the agent is exhibited and a strong adhesive force is exhibited. In the adhesive composition of the present invention, since the acrylic resin used in the adhesive of the present invention has a poly (meth) acrylic acid alkyl ester branch polymer in the molecular side chain, the adhesive is applied to the adherend. There is a tendency that the conformability and wettability are greatly improved, the curability at the adherend interface is improved, and the adhesive force at the interface with the adherend is improved.

  In the adhesive composition of the present invention, the poly (meth) acrylic acid alkyl ester macromonomer preferably used in the present invention is preferably 0, based on the total amount of acrylic monomers used for acrylic resin production being 100% by weight. It is desirable to use 2 to 30% by weight, more preferably 0.5 to 20% by weight, and still more preferably 1.0 to 20% by weight. In the adhesive composition of the present invention, when the amount of poly (meth) acrylic acid alkyl ester macromonomer used is less than 0.2% by weight, the diffusion and mixing of the main agent and curing agent do not proceed smoothly, and There are cases where poor curing occurs at the interface of the bonded body. When the amount of the poly (meth) acrylic acid alkyl ester macromonomer used exceeds 30% by weight, the incompatibility inside the acrylic resin molecule becomes too strong, and the tendency for the adhesive force to decrease is observed.

  In the adhesive composition of the present invention, preferably, the adhesive strength can be further increased by having (a) the chemical structure (a3) represented by the following structure in the molecular main chain.

Here, z represents a mole fraction, preferably 0.001 to 0.50. At this time, the mole fraction x of the chemical structure (a1) is preferably 0.10 to 0.997. The molar fraction y of the chemical structure (a2) is preferably 0.002 to 0.40. The mole fraction z is more preferably 0.01 to 0.1. The chemical structure (a3) can be preferably added by using N-vinylpyrrolidone at the time of producing the acrylic resin, whereby the adhesive strength can be further improved. When the molar fraction z is 0.001 to 0.50, the effect of improving the adhesive strength is sufficient.

  In the adhesive composition of the present invention, the acrylic resin can be applied by a known polymerization method such as solution polymerization, suspension polymerization, emulsion polymerization, etc., but is preferably produced by bulk radical copolymerization. . In the adhesive composition of the present invention, when the acrylic resin is produced by bulk radical copolymerization, the amount of organic solvent and unreacted acrylic monomer which are unnecessary or undesirable as the adhesive contained in the acrylic resin is minimized. There is a tendency to positively affect the storage stability, curability and adhesive strength of the adhesive. In the adhesive composition of the present invention, from this viewpoint, it is recommended that the polymerization rate of the acrylic resin is preferably 90% or more, more preferably 95% or more, and still more preferably 97% or more. Here, in the adhesive composition of the present invention, bulk radical copolymerization refers to a composition (for example, “Radical Polymerization Handbook” (published by NTS, 1999, p. 6,491, 499, 505, 566). The method described in the above. That is, in the adhesive composition of the present invention, bulk radical copolymerization is one of the methods used when performing radical copolymerization of monomers having vinyl groups such as acrylic monomers and styrene monomers. Without using a solvent, polymerization is carried out by heating only a monomer having a vinyl group such as an acrylic monomer or a styrene monomer or by adding a polymerization initiator such as azobisisobutyronitrile or benzoyl peroxide. Is the method.

  In the adhesive composition of the present invention, a bulk radical copolymer preferably selected as a method for producing an acrylic resin is preferably an α-methylstyrene dimer represented by the following structural formula.

The polymerization initiator is preferably 0.1 to 1.0 mol, more preferably 0.2 to 0.85 mol, and still more preferably 0.25 to 0.84 mol with respect to 1 mol of It is recommended to be used in a range and bulk radical copolymerized. In the adhesive composition of the present invention, when the amount of the polymerization initiator used is in the range of 0.1 to 1.0 mol, it is easy to control the polymerization temperature at the time of bulk radical copolymerization, There is no runaway reaction, and there is a tendency that acrylic resins can be produced at industrially advantageous production temperatures and production times.

  In the adhesive composition of the present invention, organic initiators such as benzoyl peroxide, t-butyl-peroxy-2-ethylhexanoate, and t-butylperoxy-benzoate are preferably used as polymerization initiators preferably used for the production of acrylic resins. Peroxide, 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylvaleroisobutyronitrile), 2,2'-azobis (2-methylbutyronitrile), etc. And organic azo polymerization initiators. In the adhesive composition of the present invention, these polymerization initiators may be used alone or in a mixture of two or more. In the adhesive composition of the present invention, the polymerization initiator preferably used for the production of the acrylic resin is preferably 0.02 to 20 with the total amount of the acrylic monomers used for the acrylic resin being 100 parts by weight. Part by weight, more preferably 0.05 to 18 parts by weight, and still more preferably 0.05 to 16 parts by weight is used. In the adhesive composition of this invention, when the usage-amount of a polymerization initiator is 0.02-20 weight part, the tendency for the polymerization temperature control at the time of acrylic resin manufacture to become easy is seen.

  In the adhesive composition of the present invention, the weight average molecular weight of the acrylic resin is preferably 3000 to 200,000, the acid value is preferably 3.0 to 35 mgKOH, and the hydroxyl value is preferably 5 to 70 mgKOH. It is desirable.

  In the adhesive composition of the present invention, the weight average molecular weight of the acrylic resin is preferably 3000 to 200,000, more preferably 5000 to 160,000, and still more preferably 20,000 to 120,000. In the adhesive composition of the present invention, when the weight average molecular weight of the acrylic resin is 3000 to 200,000, the handling property of the adhesive and the tendency to slip on the adherend are observed, and the adhesive force is improved. Is seen. Here, in the adhesive composition of the present invention, the weight average molecular weight of the acrylic resin was measured using gel permeation chromatography (GPC) HLC-8220 GPC (test apparatus of Tosoh Corporation).

  In the adhesive composition of the present invention, the acid value of the acrylic resin is preferably 3.0 to 35 mgKOH, more preferably 5.0 to 30 mgKOH, and still more preferably 5.0 to 20 mgKOH. In the adhesive composition of the present invention, when the acid value of the acrylic resin is 3.0 to 35 mgKOH, a strong interaction is exerted with the adherend, and the tendency to improve the adhesive strength is observed. Here, in the adhesive composition of the present invention, the acid value of the acrylic resin was measured according to JIS K 5407: 1997.

  In the adhesive composition of the present invention, the hydroxyl value of the acrylic resin is preferably 5 to 70 mgKOH, more preferably 8 to 35 mgKOH, and still more preferably 10 to 30 mgKOH. In the adhesive composition of the present invention, when the hydroxyl value of the acrylic resin is 5 to 70 mg KOH, a strong interaction is exerted with the adherend, and the adhesive strength tends to be improved. Here, in the adhesive composition of the present invention, the hydroxyl value of the acrylic resin is based on the weight fraction (%) of the hydroxyl group-containing acrylic monomer in the acrylic monomer used in the acrylic resin. Calculation was performed by weight fraction (%) of acrylic monomer / molecular weight of hydroxyl group-containing acrylic monomer × 561.

  The adhesive composition of the present invention is preferably an adhesive composition, preferably a dicyclopentadienyl group-containing acrylic monomer having the following structural formula

(Here, R9 represents a hydrogen atom or a methyl group, and a represents 0 or an integer of 1 to 4.)
It is recommended to include

  In the adhesive composition of the present invention, the dicyclopentadienyl group-containing acrylic monomer preferably used in the adhesive composition of the present invention includes dicyclopentenyloxy acrylate, dicyclopentenyloxyethyl acrylate, and dicyclopentenyl. Examples thereof include oxymethacrylate and dicyclopentenyloxyethyl methacrylate. In the adhesive composition of the present invention, these preferably used dicyclopentadienyl group-containing acrylic monomers may be used alone or in a mixture of two or more. Examples of the dicyclopentadienyl group-containing acrylic monomer preferably used in the adhesive composition of the present invention include “FANCYL FA-511”, “FANCRYL FA-512M” (hereinafter referred to as Hitachi Chemical). Industrial products) and the like.

  In the adhesive composition of the present invention, the dicyclopentadienyl group-containing acrylic monomer preferably used in the present invention improves the curability of the adhesive, and further suppresses the inhibition of curing by oxygen, thereby reducing the iron and aluminum. There is a tendency to improve the adhesive strength to alloys, metals such as copper, and plastics such as polypropylene alloy, nylon and ABS resin.

  In the adhesive composition of the present invention, the dicyclopentadienyl group-containing acrylic monomer preferably used in the present invention is preferably used in an amount of 100 parts by weight of the acrylic resin, preferably 2 to 400 parts by weight, more preferably It is desirable to use 5 to 300 parts by weight, more preferably 10 to 250 parts by weight. In the adhesive composition of the present invention, when the amount of the dicyclopentadienyl group-containing acrylic monomer is 2 to 400 parts by weight, the adhesive property of the adhesive to the adherend is improved and the adhesive force is improved. Is seen.

  In the adhesive composition of the present invention, the adhesive composition is preferably an ethylene oxide-modified bisphenol A di (meth) acrylate having the following structural formula

(Here, R10 represents a hydrogen atom or a methyl group, R11 represents a hydrogen atom or a methyl group, and b and c represent an integer of 1 to 10.)
It is recommended to include

As ethylene oxide modified bisphenol A di (meth) acrylate preferably used in the adhesive composition of the present invention, for example, “NK ester BPE-100”, “NK ester BPE-200”, “ NK Ester BPE-300, NK Ester BPE-500, NK Ester BPE-1300N, NK Ester ABE-300, NK Ester A-BPE-4, NK Ester A-BPE-10 (Above, products of Shin-Nakamura Chemical), "Aronix M-210" (above, products of Toagosei), "FANCYL FA-321A", "FANCRYL FA-324A", "FANCRYL FA-320M", "FANCRYL FA- 321M "," FANCYL FA-3218M " Products), and the like of the Chemical Industry. In the adhesive composition of the present invention, these ethylene oxide-modified bisphenol A di (meth) acrylates may be used alone or in a mixture of two or more. In the adhesive composition of the present invention, the present The ethylene oxide-modified bisphenol A di (meth) acrylate preferably used in the invention improves the curability of the adhesive in the same manner as the dicyclopentadienyl group-containing acrylic monomer preferably used in the present invention. There is a tendency to improve the adhesive strength to aluminum alloys, metals such as copper, and plastics such as polypropylene alloy, nylon, and ABS resin.

  In the adhesive composition of the present invention, the ethylene oxide-modified bisphenol A di (meth) acrylate preferably used in the present invention is preferably 2 to 400 parts by weight, more preferably 100 parts by weight of the acrylic resin. 5 to 300 parts by weight, more preferably 10 to 200 parts by weight. In the adhesive composition of the present invention, when the amount of ethylene oxide-modified bisphenol A diacrylate is 2 to 400 parts by weight, the curability of the adhesive tends to be improved and the adhesive force tends to be improved.

  In the adhesive composition of the present invention, it is recommended to use a curing agent and a curing accelerator, preferably for three-dimensional crosslinking of the adhesive, to increase the mechanical strength of the adhesive and to improve the adhesive strength. Is done.

In the adhesive composition of the present invention, the use of an organic peroxide is recommended as the curing agent preferably used. In the adhesive composition of the present invention, preferably used organic peroxides are methyl ethyl ketone peroxide, cyclohexanone peroxide, methylcyclohexanone peroxide, 1,1-bis (t-hexylperoxy) 3, 3, 5 -Trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, cumene hydroperoxide, benzoyl peroxide and the like are exemplified. In the adhesive composition of the present invention, these organic peroxides may be used alone or in a mixture of two or more. (References on organic peroxides: Chemical products of 15308, Chemical Industry Daily (2008), p628-650)
In the adhesive composition of the present invention, the organic peroxide preferably used as the curing agent is preferably 0.02 to 20 parts by weight, more preferably 0.2 to 100 parts by weight of the adhesive composition. It is desirable to use 10 to 10 parts by weight, more preferably 0.1 to 10 parts by weight. In the adhesive composition of the present invention, when the amount of the organic peroxide preferably used as the curing agent is 0.02 to 20 parts by weight, the adhesive has good curability and is relatively low temperature (room temperature to 60 ° C. ), A tendency to exhibit practically sufficient adhesive strength in a short time (several minutes to 60 minutes) is observed.

  In the adhesive composition of the present invention, preferable examples of the adhesion promoter preferably include transition metal salts, urea compounds, saccharin, tertiary amine compounds such as N, N-dimethylparatoluidine, and the like. In the adhesive composition of the present invention, it is recommended to use an organometallic soap as the transition metal salt preferably used. In the adhesive composition of the present invention, the organometallic soap preferably used in the present invention includes cobalt naphthenate, manganese naphthenate, iron naphthenate, calcium naphthenate, zinc naphthenate, lead naphthenate, copper naphthenate, Examples include manganese naphthenate, vanadium naphthenate, cobalt octylate, manganese octylate, iron octylate, calcium octylate, zinc octylate, lead octylate, copper octylate, manganese octylate, and vanadium octylate. In the adhesive composition of the present invention, these organometallic soaps may be used alone or in a mixture of two or more. In the adhesive composition of the present invention, ethylene thiourea, trimethylthiourea and the like are exemplified as urea compounds that are preferably used. In the adhesive composition of the present invention, these urea compounds may be used alone or as a mixture of two or more. In the adhesive composition of the present invention, a compound such as N, N-dimethylacetamide or N, N-dimethylacetoacetamide may be used in combination with a transition metal salt or a urea compound in order to further improve curability. Good.

  In the adhesive composition of the present invention, the curing accelerator preferably used in the present invention is preferably 0.02 to 20 parts by weight, more preferably 0.2 to 0.2 parts by weight with respect to 100 parts by weight of the adhesive composition. It is desirable to use 10 parts by weight, more preferably 0.1 to 10 parts by weight. In the adhesive composition of the present invention, when the amount of the curing accelerator preferably used is 0.02 to 20 parts by weight, the adhesive has good curability and is relatively low temperature (room temperature to 60 ° C.) for a short time. There is a tendency to exhibit sufficient adhesive strength in (several minutes to 60 minutes). Moreover, the tendency which can reduce the hardening inhibition by air is seen.

  In the adhesive composition of the present invention, a polymerization inhibitor or an antioxidant can be preferably used in order to improve the storage stability of the adhesive. In the adhesive composition of the present invention, preferably used polymerization inhibitors and antioxidants include p-methoxyphenol, toluhydroquinone, t-butylcatechol, 4-benzoyl-2,2,6,6-tetramethyl. -Hindered amine compounds such as piperidine are exemplified. In the adhesive composition of the present invention, these polymerization inhibitors and antioxidants preferably used may be used alone or in a mixture of two or more.

  In the adhesive composition of the present invention, preferably used polymerization inhibitor and antioxidant are preferably 50 to 5000 ppm, more preferably 100 to 3000 ppm, and still more preferably 200 to 2000 ppm of the total amount of the adhesive. Is desirable. In the adhesive composition of the present invention, when 50 to 5000 ppm of a polymerization inhibitor and an antioxidant that are preferably used are used, it is desirable to balance the storage stability and curability of the adhesive.

  The manufacturing method of the adhesive composition of this invention and the adhesion | attachment method can be illustrated as follows.

  A predetermined amount of acrylic resin and, if necessary, a predetermined amount of a reactive diluent such as dicyclopentadienyl group-containing acrylic monomer, ethylene oxide-modified bisphenol A di (meth) acrylate, and a crosslinking agent in a mixing container Charge and mix until uniform. In the case of foaming, defoaming is performed with a defoaming device such as “Mazerustar KK-100” (Kurabo's stirring, mixing, defoaming device) to produce an adhesive resin.

  (1) Before applying the adhesive to the adherend, the adhesive resin and the curing agent are mixed, and if necessary, a predetermined amount of a curing accelerator is mixed, and the adhesive is applied to the adherend with a predetermined film thickness. A curing reaction is performed for a predetermined time at a temperature to perform adhesion.

  (2) In the adhesive composition of the present invention, an adhesive can also be produced and used as follows. An adhesive resin is produced as described above. This is divided into two, and a predetermined amount of curing agent is mixed in one (adhesive main agent A). A curing accelerator is mixed in the other adhesive resin (adhesive main agent B).

  2-1. Adhesive main agent A and adhesive main agent B are mixed before bonding, applied to the adherend, and the adhesive is cured by a predetermined reaction to complete the bonding.

  2-2. When adhesive main agent A is applied to one of the adherends with a predetermined film thickness (adhesive member A), and adhesive main agent B is applied to the other adherend with a predetermined film thickness (adhesive member B) for bonding The surfaces coated with the adhesive main agent A and the adhesive main agent B are pressure-bonded to each other and subjected to a curing reaction at a predetermined temperature for a predetermined time to perform bonding.

  In the adhesive composition of the present invention, since the acrylic resin is a graft copolymer, when the adhesive member A and the adhesive member B are pressure-bonded to the surface on which the adhesive agent A and the adhesive agent B are applied, Adhesive main agent A and adhesive main agent B are uniformly mixed by the transport phenomenon and diffusion action derived from the graft copolymer, and adhesion can be achieved at low temperature and in a short time without causing poor curing.

  In this bonding method, it is possible to independently produce the bonding member A and the bonding member B, and it is possible to arbitrarily set the bonding timing, which is advantageous in terms of production efficiency.

  In the adhesive composition of the present invention, in addition to these, various additives such as thickeners, thixotropic agents, antifoaming agents, nueles, various reinforcing fillers such as glass fibers, carbon fibers, montmorillonite, calcium carbonate , Titanium white, glass powder, silica particles, pigments such as alumina, extenders, silane coupling agents such as γ-glycidoxypropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, various adhesives and paints What is generally blended with can also be blended.

  Next, the example of the acrylic resin manufacturing method preferably selected with the adhesive composition of this invention is shown below.

[Examples of acrylic resin production]
A 2 L four-necked flask equipped with a reflux condenser, thermometer, stirrer, and inert gas inlet is blown with a nitrogen gas / air mixed gas (oxygen concentration: 3 vol%), and the oxygen concentration in the flask is reduced to 3 vol%. did. Thereafter, a mixture gas of nitrogen gas / air (oxygen concentration: 3 vol%) was blown during the polymerization of the acrylic resin. The oxygen concentration was measured with a digital oxygen concentration meter XO-326ALB (measurement device of Shin Cosmos Electric Co., Ltd.).

  780 g of n-butyl acrylate, 100 g of 2-methoxyethyl acrylate, 75 g of 2-hydroxyethyl methacrylate, 15 g of methacrylic acid, 30 g of “Aron Macromer AA-6” (polymethyl methacrylate macromonomer manufactured by Toagosei Co., Ltd.) 300 g of the monomer mixture (total amount: 1000 g) and 70 g of α-methylstyrene dimer (7 wt% of the total amount of acrylic monomers) were charged into a flask and heated to 92 ° C. over 30 minutes.

  24.3 g of 2,2′-azobisisobutyronitrile (0.5 mol when the number of moles of α-methylstyrene dimer is 1 mol) is dissolved in the remaining 700 g of the acrylic monomer mixture, In 3 hours. Thereafter, the polymerization was continued for 3 hours, the temperature was raised to 105 ° C., and an aging reaction was performed for 2 hours.

  The produced acrylic graft copolymer having a carboxyl group, a hydroxyl group, and polymethyl methacrylate in the molecular side chain has a weight average molecular weight of 56,000, an acid value of 9.8 mgKOH, a hydroxyl value of 32.4 mgKOH, a polymerization rate (heating) The balance) was 98.9%.

  After cooling to 85 ° C., a nitrogen gas / air mixture (oxygen concentration: 8 vol%) was blown to confirm that the oxygen concentration in the flask was 8-12 vol%.

1.03 g of p-methoxyphenol (polymerization inhibitor) and 2.06 g of dibutyltin dilaurate (addition reaction catalyst) were charged. Subsequently, 27 g of 2-isocyanatoethyl methacrylate was added dropwise over 30 minutes, and an addition reaction was carried out using a Fourier transform infrared spectrophotometer (FT-IR) until absorption at 2300 cm ⁻¹ based on the NCO group disappeared. .

  The produced acrylic resin having a carboxyl group, a hydroxyl group, a methacrylic unsaturated group, and polymethyl methacrylate in the molecular side chain has a weight average molecular weight of 63,000, an acid value of 9.8 mgKOH, a hydroxyl value of 22.1 mgKOH, a polymerization rate. (Heating residue) was 99.6%.

  Examples of the present invention will be described below with reference to examples.

  In the examples, tests, evaluation methods, etc. were carried out according to the following.

1) Oxygen concentration (vol%)
The measurement was performed using a digital oximeter XO-326ALB (a measuring device manufactured by Shin Cosmos Electric Co., Ltd.).

2) Weight average molecular weight (also called Mw)
It measured using the gel permeation chromatography (GPC) HLC-8220GPC (the test device of Tosoh Corporation).

3) Heating residue (%)
Measured according to JIS K 5407: 1997. However, the measurement temperature was 140 ° C. and the measurement time was 30 minutes.

4) Acid value It measured according to JISK5407: 1997.

5) Tensile shear strength (MPa)
In accordance with JIS K 6850: 1999, the thickness of the adhesive is 500 μm, left at 23 ° C. (23 ° C.), 80 ° C. for 10 days, and then performed at 23 ° C. (80 ° C.-23 ° C.), 80 ° C. (80 ° C.-80 ° C.). It was.

  The curing conditions for the adhesive were a curing temperature of 30 ° C. and a curing time of 30 minutes. An aluminum alloy (JIS A-2017P: 1999) was used as the adherend.

  In the examples, the composition ratio was weight ratio unless otherwise specified.

Example of production of acrylic resin Production Example of Acrylic Resin (1) Nitrogen gas is introduced into a 2 L four-necked flask having a nitrogen gas inlet tube, a reflux condenser, a stirring device, and an acrylic monomer charging port until the oxygen concentration in the flask becomes 5 vol% or less. During blowing and polymerization, blowing of a nitrogen gas / oxygen gas mixture adjusted to an oxygen concentration of 3 to 5 vol% was continued.

  780 g of n-butyl acrylate, 100 g of 2-methoxyethyl acrylate, 75 g of 2-hydroxyethyl methacrylate, 15 g of methacrylic acid / “Aron Macromer AA-6” (polymethyl methacrylate macromonomer made by Toagosei, weight average molecular weight 6000 (Polymerization degree z = 60)) 30 g (= 78/10 / 7.5 / 1.5 / 3) 300 g out of a total amount of 1000 g of acrylic monomer, and 70 g of α-methylstyrene dimer (acrylic monomer) 7 parts by weight when the total amount was 100 parts by weight) was charged into a flask and heated to 92 ° C.

  In the remaining 700 g of the acrylic monomer mixed solution, 24.3 g of 2,2′-azobisisobutyronitrile (polymerization initiator) (0.5 mol when α-methylstyrene dimer was 1 mol) was dissolved. The monomer solution was dropped into the flask in 3 hours. Thereafter, polymerization was performed at 92 ° C. for 3 hours, and the temperature was raised to 105 ° C., followed by further aging for 2 hours, and an acrylic copolymer having a carboxyl group, a hydroxyl group, and a polymethyl methacrylate branch polymer in the molecular side chain ( 1) was produced.

  Cooled to 85 ° C. Oxygen / air mixed gas (oxygen concentration 8 vol%) was blown in until the oxygen concentration in the flask became 12 vol% or lower, and oxygen / air mixed gas (oxygen concentration 8 vol%) was blown in continuously during the subsequent addition reaction. It is.

The flask was charged with 1.027 g of p-methoxyphenol and 2.05 g of dibutyltin dilaurate. 27 g of 2-isocyanatoethyl methacrylate (30 mol% of 2-hydroxyethyl methacrylate) was added dropwise over 30 minutes, and then 2300 cm ⁻ while tracing the reaction with a Fourier transform infrared spectrophotometer (FT-IR). ^The addition reaction was carried out until there was no absorption of NCO near ¹ . After cooling to room temperature, an acrylic resin (1) having a methacryloyl group derived from an isocyanate group-containing acrylic monomer in the molecular side chain was produced.

  The acrylic resin (1) had a weight average molecular weight of 62,000, a heating residue of 99.8%, an acid value of 9.5 mgKOH, and a hydroxyl value of 22.1 mgKOH.

2. Production Example of Acrylic Resin (2) Nitrogen gas is introduced into a 2 L four-necked flask having a nitrogen gas inlet tube, a reflux condenser, a stirring device, and an acrylic monomer charging port until the oxygen concentration in the flask becomes 5 vol% or less. During blowing and polymerization, blowing of a nitrogen gas / oxygen gas mixture adjusted to an oxygen concentration of 3 to 5 vol% was continued.

  790 g of n-butyl acrylate, 100 g of 2-methoxyethyl acrylate, 50 g of 2-hydroxyethyl methacrylate, 30 g of methacrylic acid / “Aron Macromer AA-6” (polymethyl methacrylate macromonomer made by Toagosei, weight average molecular weight 6000 (Degree of polymerization z = 60)) 30 g (= 79/10/5/3/3) 300 g out of a total amount of 1000 g of acrylic monomer, and 70 g of α-methylstyrene dimer (total amount of acrylic monomer is 100 wt. 7 parts by weight), and the temperature was raised to 92 ° C.

  In the remaining 700 g of the acrylic monomer mixed solution, 24.3 g of 2,2′-azobisisobutyronitrile (polymerization initiator) (0.5 mol when α-methylstyrene dimer was 1 mol) was dissolved. The monomer solution was dropped into the flask in 3 hours. Thereafter, polymerization was performed at 92 ° C. for 3 hours, and the temperature was raised to 105 ° C., followed by further aging for 2 hours, and an acrylic copolymer having a carboxyl group, a hydroxyl group, and a polymethyl methacrylate branch polymer in the molecular side chain ( 2) was produced.

  Cooled to 85 ° C. Oxygen / air mixed gas (oxygen concentration 8 vol%) was blown in until the oxygen concentration in the flask became 12 vol% or lower, and oxygen / air mixed gas (oxygen concentration 8 vol%) was blown in continuously during the subsequent addition reaction. It is.

  The flask was charged with 1.025 g of p-methoxyphenol and 2.05 g of N, N-dimethylbenzylamine. 25 g of glycidyl methacrylate (50 mol% of methacrylic acid) was added dropwise over 30 minutes, and then an addition reaction was performed until the acid value reached a predetermined value. After cooling to room temperature, an acrylic resin (2) having a methacryloyl group derived from glycidyl methacrylate in the molecular side chain was produced.

  The acrylic resin (2) had a weight average molecular weight of 67,000, a heating residue of 99.8%, an acid value of 9.5 mgKOH, and a hydroxyl value of 22.1 mgKOH.

3. Production Example of Acrylic Resin (3) Nitrogen gas is introduced into a 2 L four-necked flask having a nitrogen gas inlet tube, a reflux condenser, a stirrer, and an acrylic monomer charging port until the oxygen concentration in the flask becomes 5 vol% or less. During blowing and polymerization, blowing of a nitrogen gas / oxygen gas mixture adjusted to an oxygen concentration of 3 to 5 vol% was continued.

  910 g of 2-ethylhexyl acrylate, 30 g of acrylic acid, 30 g of N-vinylpyrrolidone / “Aron Macromer AA-6” (polymethyl methacrylate macromonomer manufactured by Toagosei Co., Ltd., weight average molecular weight 6000 (polymerization degree z = 60)) 30 g ( = 91/3/3/3) 300 g of 1000 g of the total amount of acrylic monomers and 2 g of α-methylstyrene dimer (0.2 parts by weight when the total amount of acrylic monomers is 100 parts by weight), The flask was charged and heated to 92 ° C.

  In the remaining 700 g of the acrylic monomer mixed solution, 0.35 g of 2,2′-azobisisobutyronitrile (polymerization initiator) (0.25 mol when α-methylstyrene dimer was 1 mol) was dissolved. The monomer solution was dropped into the flask in 3 hours. Thereafter, polymerization is carried out for 3 hours at 92 ° C., the temperature is raised to 105 ° C., and the mixture is further aged for 2 hours, whereby an acrylic copolymer having a carboxyl group and a polymethyl methacrylate branch polymer in the molecular side chain (3) Manufactured.

  Cooled to 85 ° C. Oxygen / air mixed gas (oxygen concentration 8 vol%) was blown in until the oxygen concentration in the flask became 12 vol% or lower, and oxygen / air mixed gas (oxygen concentration 8 vol%) was blown in continuously during the subsequent addition reaction. It is.

  A flask was charged with 0.5 g of p-methoxyphenol and 4 g of N, N-dimethylbenzylamine. 30 g of glycidyl methacrylate (50 mol% of acrylic acid) was added dropwise over 30 minutes, and then an addition reaction was performed until the acid value reached a predetermined value. After cooling to room temperature, an acrylic resin (3) having a methacryloyl group derived from glycidyl methacrylate in the molecular side chain was produced.

  The acrylic resin (3) had a weight average molecular weight of 200,000, a heating residue of 95.2%, and an acid value of 11.2 mgKOH.

4). Production Example of Acrylic Resin (4) Nitrogen gas is introduced into a 2 L four-necked flask having a nitrogen gas inlet tube, a reflux condenser, a stirrer, and an acrylic monomer charging port until the oxygen concentration in the flask becomes 5 vol% or less. During blowing and polymerization, blowing of a nitrogen gas / oxygen gas mixture adjusted to an oxygen concentration of 3 to 5 vol% was continued.

  820 g of n-butyl acrylate, 2-methoxyethyl acrylate 100 g, 2-hydroxyethyl methacrylate 50 g, methacrylic acid 30 g (= 82/10/5/3) 300 g out of a total amount 1000 g of acrylic monomers, and A flask was charged with 70 g of α-methylstyrene dimer (7 parts by weight when the total amount of acrylic monomers was 100 parts by weight), and the temperature was raised to 92 ° C.

  In the remaining 700 g of the acrylic monomer mixed solution, 24.3 g of 2,2′-azobisisobutyronitrile (polymerization initiator) (0.5 mol when α-methylstyrene dimer was 1 mol) was dissolved. The monomer solution was dropped into the flask in 3 hours. Thereafter, polymerization was carried out at 92 ° C. for 3 hours, and the temperature was raised to 105 ° C., followed by further aging for 2 hours to produce an acrylic copolymer (4) having a carboxyl group and a hydroxyl group in the molecular side chain.

  Cooled to 85 ° C. Oxygen / air mixed gas (oxygen concentration 8 vol%) was blown in until the oxygen concentration in the flask became 12 vol% or lower, and oxygen / air mixed gas (oxygen concentration 8 vol%) was blown in continuously during the subsequent addition reaction. It is.

  The flask was charged with 1.025 g of p-methoxyphenol and 2.05 g of N, N-dimethylbenzylamine. 25 g of glycidyl methacrylate (50 mol% of methacrylic acid) was added dropwise over 30 minutes, and then an addition reaction was performed until the acid value reached a predetermined value. After cooling to room temperature, an acrylic resin (4) having a methacryloyl group derived from glycidyl methacrylate in the molecular side chain was produced.

  The acrylic resin (4) had a weight average molecular weight of 62,000, a heating residue of 99.2%, an acid value of 10.2 mgKOH, and a hydroxyl value of 21.8 mgKOH.

5. Production Example of Acrylic Resin (5) Nitrogen gas is introduced into a 2 L four-necked flask having a nitrogen gas inlet tube, a reflux condenser, a stirrer, and an acrylic monomer charging port until the oxygen concentration in the flask becomes 5 vol% or less. During blowing and polymerization, blowing of a nitrogen gas / oxygen gas mixture adjusted to an oxygen concentration of 3 to 5 vol% was continued.

  940 g of 2-ethylhexyl acrylate, 30 g of acrylic acid, 30 g of N-vinylpyrrolidone (= 94/3/3) 300 g out of a total amount of 1000 g of acrylic monomer, and 2 g of α-methylstyrene dimer (total amount of acrylic monomer) Was 0.2 parts by weight with respect to 100 parts by weight), and the temperature was raised to 92 ° C.

  In the remaining 700 g of the acrylic monomer mixed solution, 0.35 g of 2,2′-azobisisobutyronitrile (polymerization initiator) (0.25 mol when α-methylstyrene dimer was 1 mol) was dissolved. The monomer solution was dropped into the flask in 3 hours. Thereafter, polymerization was carried out at 92 ° C. for 3 hours, and the temperature was raised to 105 ° C., followed by further aging for 2 hours to produce an acrylic copolymer (5) having a carboxyl group in the molecular side chain.

  Cooled to 85 ° C. Oxygen / air mixed gas (oxygen concentration 8 vol%) was blown in until the oxygen concentration in the flask became 12 vol% or lower, and oxygen / air mixed gas (oxygen concentration 8 vol%) was blown in continuously during the subsequent addition reaction. It is.

  A flask was charged with 0.5 g of p-methoxyphenol and 4 g of N, N-dimethylbenzylamine. 30 g of glycidyl methacrylate (50 mol% of acrylic acid) was added dropwise over 30 minutes, and then an addition reaction was performed until the acid value reached a predetermined value. After cooling to room temperature, an acrylic resin (5) having a methacryloyl group derived from glycidyl methacrylate in the molecular side chain was produced.

  The acrylic resin (5) had a weight average molecular weight of 190,000, a heating residue of 96.2%, and an acid value of 11.3 mgKOH.

Table 1 shows the composition of the acrylic copolymer, and Table 2 shows the acrylic resin composition and characteristic values.
In Tables 1 and 2, * 1 is a chemical structure represented by the following structural formula

(Where R1 is a hydrogen atom or a methyl group, R2 is a hydrogen atom, an alkyl group having 2 to 12 carbon atoms, a hydroxyalkyl group having 2 to 6 carbon atoms in the alkyl group, or an alkyl group) A methoxyalkyl group having 2 to 6 carbon atoms, x represents a mole fraction, and is 0.40 to 0.998.)
And x is the molar fraction of the chain unit composed of the acrylic monomer.

  * 2 is a poly (meth) acrylic acid alkyl ester branched polymer represented by the following structural formula

(Here, R8 is a hydrogen atom or a methyl group, R9 is an alkyl group having 1 to 8 carbon atoms, and p represents the degree of polymerization and is an integer of 20 to 500.)
Represents
* 3 is the chemical structure shown by the following structural formula

(Where R3 represents a hydrogen atom or a methyl group, and W is a chemical structure represented by the following structural formula.

(Here, R4 represents an alkyl group having 2 to 6 carbon atoms, R5 represents an alkyl group having 2 to 4 carbon atoms, and R6 represents a hydrogen atom or a methyl group.)
Or the chemical structure shown by the following structural formula

(Here, R7 represents a hydrogen atom or a methyl group.)
Y represents a mole fraction and is 0.002 to 0.60. )
Y represents the mole fraction occupied by this chain unit;
* 4 is the chemical structure shown by the following structural formula

(Here, z represents a mole fraction and is 0.001 to 0.50.)

Examples 1-9
Table 3 shows the compositions of the adhesives 1 to 9 of Examples 1 to 9. In the table,
* 1) FANCYL FA-512M: dicyclopentenyloxyethyl methacrylate manufactured by Hitachi Chemical Co., Ltd. * 2) NK ester BPE-200: ethylene oxide modified bisphenol A dimethacrylate manufactured by Shin-Nakamura Chemical Co., Ltd.

  Each adhesive was produced by uniformly mixing the raw materials of the main agent A and the main agent B, and then defoaming with “Mazerustar KK-100” (Kurabo stirring, mixing and defoaming device).

  For adhesion, the main agent A and the main agent B were separately applied to an aluminum test piece as an adherend, and then the adhesive-coated surface was crimped and the adherend was sandwiched between clips, and cured under predetermined curing conditions.

Comparative Examples 1, 2, and 3
The compositions of the adhesives 10 and 11 of Comparative Example 1 and Comparative Example 2 are shown in Table 4. In the table,
* 3) is chlorosulfonated polyethylene: Tosoh chlorosulfone polyethylene TSM-340
Represents.

  In Comparative Examples 1 and 2, the main agent and the curing agent were mixed and then defoamed with “Mazerustar KK-100” (Kurabo's stirring, mixing, and defoaming device). After the adhesive was applied to both the adherends, the adhesive application surface was crimped, the adherend was sandwiched between clips, and cured under predetermined curing conditions. In Comparative Example 3, the adhesive 10 was used, and the main agent and the curing agent were separately applied to the aluminum test piece as the adherend, then the adhesive application surface was pressure-bonded, and the adherend was sandwiched between the clips, and predetermined curing was performed. Cured at conditions.

Comparative Examples 4-9
Table 5 shows adhesives 12 to 17 of Comparative Examples 4 to 9. In the table,
* 1) FANCYL FA-512M: dicyclopentenyloxyethyl methacrylate manufactured by Hitachi Chemical Co., Ltd. * 2) NK ester BPE-200: ethylene oxide modified bisphenol A dimethacrylate manufactured by Shin-Nakamura Chemical Co., Ltd.

  Each adhesive was produced by uniformly mixing the raw materials of the main agent A and the main agent B, and then defoaming with “Mazerustar KK-100” (Kurabo stirring, mixing and defoaming device).

  For adhesion, the main agent A and the main agent B were separately applied to an aluminum test piece as an adherend, and then the adhesive-coated surface was crimped and the adherend was sandwiched between clips, and cured under predetermined curing conditions.

  Table 6 shows the test results of the adhesives of the examples (adhesives 1 to 9) and the adhesives of the comparative examples (adhesives 10 to 17). As is apparent from Table 6, adhesives 1 to 9 were excellent in curability and exhibited good adhesive force and adhesive state. On the other hand, although the adhesives 10 and 11 exhibited the adhesive force at the initial stage, the adhesive force was greatly reduced after the heat resistance test. Further, the adhesion state was also interfacial peeling, which was not preferable as the adhesion state. Further, as seen in Comparative Example 3, the adhesive 10 was not cured by the method of coating the adherend similarly to the adhesives 1-6. Furthermore, as seen in Comparative Examples 4 to 9, the adhesives 12 to 14 using the acrylic resin (4) not using the polymethyl methacrylate macromonomer and the polymethyl methacrylate macromonomer are not used. However, all of the adhesives 15 to 17 using the acrylic resin (5) using N-vinylpyrrolidone had a poor adhesion state with interfacial peeling, and the adhesive strength was also lowered.

Claims (5)

(A) Chemical structure (a1) represented by the following structural formula in the molecular main chain

(Where R1 is a hydrogen atom or a methyl group, R2 is a hydrogen atom, an alkyl group having 2 to 12 carbon atoms, a hydroxyalkyl group having 2 to 6 carbon atoms in the alkyl group, or an alkyl group) (It is a methoxyalkyl group having 2 to 6 carbon atoms, and x represents a mole fraction and is 0.40 to 0.998.)
And a chemical structure (a2) represented by the following structural formula:

(Where R3 represents a hydrogen atom or a methyl group, and W is a chemical structure represented by the following structural formula.

(Here, R4 represents an alkyl group having 2 to 6 carbon atoms, R5 represents an alkyl group having 2 to 4 carbon atoms, and R6 represents a hydrogen atom or a methyl group.)
Or the chemical structure shown by the following structural formula

(Here, R7 represents a hydrogen atom or a methyl group.)
Y represents a mole fraction and is 0.002 to 0.60. )
Including
(B) Poly (meth) acrylic acid alkyl ester branched polymer represented by the following structural formula in the side chain of the molecule

(Here, R8 is a hydrogen atom or a methyl group, R9 is an alkyl group having 1 to 8 carbon atoms, and p represents the degree of polymerization and is an integer of 20 to 500.)
A two-component adhesive composition comprising an acrylic resin having In the chemical structure (a1) of the adhesive composition, R2 represents a hydrogen atom, an alkyl group having 2 to 8 carbon atoms, a hydroxyalkyl group having 2 to 4 carbon atoms in the alkyl group, or a carbon atom in the alkyl group. The two-component adhesive composition according to claim 1, which is a methoxyalkyl group having 2 to 4 atoms and x is 0.90 to 0.995. The two-component solution according to claim 1 or 2 , wherein in the chemical structure (a2) of the adhesive composition, R4 is an alkyl group having 2 to 4 carbon atoms, and y is 0.005 to 0.10. Mold adhesive composition. In the chemical structure (a2) of the adhesive composition, the chemical structure (a2) is

(Here, y represents a mole fraction and is 0.005 to 0.10.)
The two-component adhesive composition according to any one of claims 1 to 3. (A) Chemical structure (a3) represented by the following structural formula in the molecular main chain

(Here, z represents a mole fraction and is 0.001 to 0.50.)
The mole fraction x of the chemical structure (a1) is 0.10 to 0.997, and the mole fraction y of the chemical structure (a2) is 0.002 to 0.40. The two-component adhesive composition according to any one of -4.