WO2018199268A1 - 2-cyanoacrylate-based adhesive composition - Google Patents

Abstract

This 2-cyanoacrylate adhesive composition contains a 2-cyanoacrylate-based compound (A), and a thermoplastic elastomer (B), wherein the thermoplastic elastomer (B) is a block copolymer having a block (a) and a block (b), and the glass transition temperature of the block (a) is 80°C or higher, and the glass transition temperature of the block (b) is 20°C or lower.

Description

2-cyanoacrylate adhesive composition

The present invention relates to a 2-cyanoacrylate adhesive composition.

The adhesive composition containing a 2-cyanoacrylate compound is polymerized by a weak anion such as a slight amount of water adhering to the adherend surface due to the unique anionic polymerization property of the 2-cyanoacrylate compound as the main component. It is possible to bond various materials firmly in a short time. Therefore, it is used as a so-called instant adhesive in a wide range of fields such as industrial use, medical use, and home use.

However, an adhesive composition containing a 2-cyanoacrylate compound is hard and brittle and does not have a cross-linked structure. Therefore, it has excellent shear bond strength, but it has excellent peel bond strength and impact bond strength. And has a problem that heat resistance is low.
Conventionally, in order to solve these problems, methods for blending various modifiers have been proposed. However, general modifiers are not dissolved in 2-cyanoacrylate compounds, or 2-cyanoacrylate by mixing. Since the compound is anionically polymerized, the modifiers that can be incorporated into the 2-cyanoacrylate compound are limited. Examples of adhesive compositions containing such modifiers include those described in Patent Documents 1 to 3.
Patent Document 1 includes a cyanoacrylate monomer (a), a rubbery polymer core, and a glassy polymer shell, wherein the core crosslinking monomer is 0.2 to 4.0% by weight based on the core, and the graft monomer is A cyanoacrylate-based adhesive composition characterized by containing a core-shell polymer (b) in a range of 0.2 to 5.0% by weight based on the core is described.
Patent Document 2 discloses (a) a cyanoacrylate component, and (b) a reaction product of a combination of monomers substantially having (a) ethylene, methyl acrylate and a carboxylic acid curing site, and (b) ethylene. And a copolymer of methyl acrylate and a rubber toughening agent substantially selected from the combination of (a) and (b) and substantially free of mold release agent, antioxidant, stearic acid and / or polyethylene glycol ether wax A rubber toughened cyanoacrylate adhesive composition is described.
Patent Document 3 contains (a) 2-cyanoacrylic acid ester, (b) a polymer having a hydrolyzable silyl group, (c) an elastomer, and (d) an acid catalyst. When the content of the components (b), (c) and (d) is 100 parts by mass of the component (a), the component (b) is 5 to 200 parts by mass, and the component (c) is 5 to 50 parts. An adhesive composition characterized in that the component (d) is 0.0005 to 0.5 parts by mass is described.

Japanese Unexamined Patent Publication No. 7-331186 International Publication No. 2007/008971 International Publication No. 2015/033738

As a result of detailed studies, the present inventors have found that an adhesive composition containing a conventional 2-cyanoacrylate compound is resistant to repeated thermal changes, particularly between cold and heat cycle resistance, particularly between different types of adherends. It has been found that it has a problem that it is inferior in cold-heat cycle resistance.
However, the present inventors have found that, although the impact resistance is improved by the method described in Patent Document 1, the thermal cycle resistance is not sufficiently satisfactory.
Furthermore, in the method described in Patent Document 2, the present inventors have found that the elastomer used is non-crosslinkable, and is inferior in heat resistance and heat cycle resistance including a high temperature environment.

The problem to be solved by the present invention is to provide a 2-cyanoacrylate-based adhesive composition that is excellent in storage stability and cold-heat cycle resistance after curing.

Means for solving the problems include the following aspects.
<1> A block copolymer containing a 2-cyanoacrylate compound (A) and a thermoplastic elastomer (B), wherein the thermoplastic elastomer (B) has a block (a) and a block (b). A 2-cyanoacrylate adhesive composition in which the glass transition temperature of the block (a) is 80 ° C. or higher and the glass transition temperature of the block (b) is 20 ° C. or lower.
<2> The 2-cyanoacrylate adhesive composition according to <1>, wherein the block (a) has at least a structural unit derived from a maleimide compound.
<3> The 2-cyanoacrylate adhesive composition according to <1> or <2>, wherein the block (a) includes at least a structural unit represented by the following formula (1).

In the formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or —Ph—R ² , Ph represents a phenylene group, R ² represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms , A hydroxy group, an alkoxy group having 1 or 2 carbon atoms, an acetyl group, or a halogen atom.

<4> The 2-cyano according to any one of <1> to <3>, wherein the block (a) has at least a structural unit derived from a maleimide compound and a structural unit derived from a styrene compound. Acrylate adhesive composition.
<5> The 2-cyanoacrylate according to any one of <1> to <4>, wherein the solubility parameter of the block (a) is 10.0 (cal / cm ³ ) ^1/2 or more. Adhesive composition.
<6> The 2-cyanoacrylate adhesive composition according to any one of <1> to <5>, wherein the block (b) is an acrylic polymer block.
<7> The 2-cyanoacrylate adhesive composition according to any one of <1> to <6>, wherein the thermoplastic elastomer (B) has a number average molecular weight of 10,000 to 500,000. object.
<8> The above <1> to <7, wherein the content of the thermoplastic elastomer (B) is 1 to 100 parts by mass with respect to 100 parts by mass of the 2-cyanoacrylate compound (A). > The 2-cyanoacrylate adhesive composition according to any one of the above.
<9> The 2-cyanoacrylate adhesive according to any one of <1> to <8>, wherein the thermoplastic elastomer (B) is a block copolymer produced by a living radical polymerization method. Composition.
<10> The thermoplastic elastomer (B) according to any one of <1> to <9>, wherein the thermoplastic elastomer (B) is a block copolymer produced by a reversible addition-cleavage chain transfer polymerization method. Cyanoacrylate adhesive composition.

According to the present invention, it is possible to provide a 2-cyanoacrylate-based adhesive composition that is excellent in storage stability and cold-heat cycle resistance after curing.

The description of the constituent elements described below may be made based on typical embodiments of the present invention, but the present invention is not limited to such embodiments. In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
In the present invention, “mass%” and “weight%” are synonymous, and “part by mass” and “part by weight” are synonymous.
In the present invention, a combination of two or more preferred embodiments is a more preferred embodiment.
Hereinafter, the contents of the present invention will be described in detail.

(2-cyanoacrylate adhesive composition)
The 2-cyanoacrylate adhesive composition of the present invention (hereinafter also simply referred to as “adhesive composition”) contains a 2-cyanoacrylate compound (A) and a thermoplastic elastomer (B), The thermoplastic elastomer (B) is a block copolymer having a block (a) and a block (b), the glass transition temperature of the block (a) is 80 ° C. or higher, and the block (b) The glass transition temperature is 20 ° C. or lower.

As a result of intensive studies by the present inventors, it has been found that by adopting the above-described configuration, it is possible to provide a 2-cyanoacrylate adhesive composition that is excellent in storage stability and cold-heat cycle resistance after curing.
Although the mechanism of the excellent effect by this is not clear, it is estimated as follows.
In the thermoplastic elastomer (B), the block (a) having a glass transition temperature of 80 ° C. or higher functions as a hard segment, and the block (b) having a glass transition temperature of 20 ° C. or lower functions as a soft segment. Presumed.
The thermoplastic elastomer (B) is physically cross-linked in the composition after being cured by the hard segment, so that it has excellent cold-heat cycle resistance and has both a hard segment and a soft segment. It is presumed that the compatibility with the 2-cyanoacrylate compound can be blended without any problem and the storage stability of the adhesive composition containing the 2-cyanoacrylate compound is excellent.
Further, the 2-cyanoacrylate adhesive composition of the present invention is excellent in cold and heat cycle resistance after curing even when used for adhesion between different types of adherends (for example, between a metal and a resin). .

<2-Cyanoacrylate compound (A)>
The adhesive composition of the present invention contains a 2-cyanoacrylate compound (A).
As the 2-cyanoacrylate compound, a 2-cyanoacrylate compound generally used in this type of adhesive composition can be used without any particular limitation. Examples of the 2-cyanoacrylate compounds include methyl, ethyl, chloroethyl, n-propyl, i-propyl, allyl, propargyl, n-butyl, i-butyl, n-pentyl, n-hexyl and cyclohexyl 2-cyanoacrylate. , Phenyl, tetrahydrofurfuryl, heptyl, 2-ethylhexyl, n-octyl, 2-octyl, n-nonyl, oxononyl, n-decyl, n-dodecyl, methoxyethyl, methoxypropyl, methoxyisopropyl, methoxybutyl, ethoxyethyl, Ethoxypropyl, ethoxyisopropyl, propoxymethyl, propoxyethyl, isopropoxyethyl, propoxypropyl, butoxymethyl, butoxyethyl, butoxypropyl, butoxyisopropyl, butoxybutyl, 2,2,2-tri Ruoroechiru and esters, such as hexafluoro isopropyl.
Of these 2-cyanoacrylate compounds, alkyl 2-cyanoacrylate or alkoxyalkyl 2-cyanoacrylate is preferable, and ethyl 2-cyanoacrylate or ethoxyethyl 2-cyanoacrylate is more preferable because of excellent curability. Furthermore, alkyl 2-cyanoacrylate is preferable from the viewpoint of curability and versatility, and alkoxyalkyl 2-cyanoacrylate is preferable from the viewpoint of heat and cold resistance after curing.

The 2-cyanoacrylate compound used in the adhesive composition of the present invention may be used alone or in combination of two or more.
The content of the 2-cyanoacrylate compound in the adhesive composition of the present invention is preferably 40% by mass or more and 100% by mass or less with respect to the total mass of the adhesive composition from the viewpoint of adhesiveness and curability. 50 mass% or more and 99.9 mass% or less is more preferable, 70 mass% or more and 99.5 mass% or less is further more preferable, and 80 mass% or more and 99.5 mass% or less is particularly preferable. preferable.

<Thermoplastic elastomer (B)>
The adhesive composition of the present invention contains a thermoplastic elastomer (B).
The thermoplastic elastomer (B) used in the present invention is a block copolymer having a block (a) and a block (b), and the glass transition temperature (Tg) of the block (a) is 80 ° C. or higher. Yes, the glass transition temperature of the block (b) is 20 ° C. or less.
The block (a) is also referred to as a polymer block (a), and the block (b) is also referred to as a polymer block (b).
The thermoplastic elastomer in the present invention is a block copolymer having a block (a) (hard segment) having a glass transition temperature of 80 ° C. or higher and a block (b) (soft segment) having a glass transition temperature of 20 ° C. or lower. It is a polymer.

The Tg of the block (a) that can be a hard segment is 80 ° C. or higher, preferably 120 ° C. or higher, more preferably 150 ° C. or higher, and particularly preferably 200 ° C. or higher. The Tg of the hard segment may be 80 ° C. or higher, which is the heat resistance temperature of general 2-cyanoacrylate adhesives, but the higher the Tg, the more the physical crosslinks even in a high temperature environment (eg 60 ° C. or 80 ° C.) Therefore, the heat resistance after curing and the thermal cycle resistance are improved.
The Tg of the block (a) is preferably 350 ° C. or less, and more preferably 300 ° C. or less.

The Tg of the block (b) that can be a soft segment is 20 ° C. or less, preferably 0 ° C. or less, and more preferably −20 ° C. or less. If the Tg of the soft segment is 20 ° C. or lower, flexibility is exhibited even at room temperature (25 ° C.). However, the lower the Tg of the soft segment, the greater the flexibility is ensured even in a low temperature environment. improves.
The Tg of the block (b) is preferably −100 ° C. or higher, and more preferably −80 ° C. or higher.

In addition, the value of Tg can be obtained by differential scanning calorimetry (DSC) as described in Examples described later.

The thermoplastic elastomer (B) may have two or more blocks (a) or two or more blocks (b), and the structure of each block (a) or block (b). May be the same or different.
The structure of the block copolymer in the thermoplastic elastomer (B) is not particularly limited, and various linear or branched block copolymers such as an AB type diblock polymer or ABA type and ABC type triblock polymer. Coalescence can be used. In view of obtaining good performance as an elastomer material, those having an A- (BA) _n- type structure such as an ABA triblock copolymer composed of block (a) -block (b) -block (a) are preferable. .

The contents of the block (a) and the block (b) in the thermoplastic elastomer (B) are based on the total mass of the thermoplastic elastomer (B) from the viewpoints of storage stability and cold cycle resistance after curing. 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more. Moreover, it is preferable that the said thermoplastic elastomer (B) is a block copolymer which consists of a block (a) and a block (b).
In addition, the total number of blocks (a) and blocks (b) in the thermoplastic elastomer (B) is preferably 2 or more and 7 or less from the viewpoint of storage stability and cold cycle resistance after curing, 2 or more and 5 or less are more preferable, and 3 is still more preferable.
Further, the thermoplastic elastomer (B) is a triblock copolymer having a structure of block (a) -block (b) -block (a) from the viewpoints of storage stability and resistance to thermal cycle after curing. Particularly preferred is a coalescence.

-Block (a)-
The thermoplastic elastomer (B) used in the present invention has at least a block (a) having a glass transition temperature of 80 ° C. or higher.
The block (a) is preferably a block containing a structural unit derived from a maleimide compound from the viewpoints of compatibility with a 2-cyanoacrylate compound, storage stability, and resistance to thermal cycle resistance after curing. A block including a structural unit derived from a maleimide compound and a structural unit derived from a styrene compound is more preferable.

The maleimide compound includes maleimide and N-substituted maleimide compounds. Examples of N-substituted maleimide compounds include N-methylmaleimide, N-ethylmaleimide, Nn-propylmaleimide, N-isopropylmaleimide, Nn-butylmaleimide, N-isobutylmaleimide, N-tert-butylmaleimide N-alkyl substituted maleimide compounds such as N-pentylmaleimide, N-hexylmaleimide, N-heptylmaleimide, N-octylmaleimide, N-laurylmaleimide, N-stearylmaleimide; N-cyclopentylmaleimide, N-cyclohexylmaleimide, etc. N-cycloalkyl substituted maleimide compounds; N-phenylmaleimide, N- (4-hydroxyphenyl) maleimide, N- (4-acetylphenyl) maleimide, N- (4-methoxyphenyl) maleimide, N- (4- N-aryl-substituted maleimide compounds such as toxiphenyl) maleimide, N- (4-chlorophenyl) maleimide, N- (4-bromophenyl) maleimide, N-benzylmaleimide, etc., and one or two of them The above can be used. By polymerizing a monomer containing a maleimide compound, a structural unit derived from the maleimide compound can be introduced into the block (a).

Among these, the block (a) has at least a structural unit represented by the following formula (1) as a structural unit derived from the maleimide compound, from the viewpoints of storage stability and cold-heat cycle resistance after curing. It is more preferable.

In formula (1), R ¹ represents a hydrogen atom, an alkyl group or an aryl group.

The alkyl group for R ¹ in the formula (1) preferably has 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, and still more preferably 1 to 3 carbon atoms. In addition, the alkyl group may be linear, branched, or a ring structure, and may have the following substituents.
Examples of the substituent include a hydroxy group, an alkoxy group, an acetyl group, a halogen atom, and an aryl group.
The aryl group in R ¹ of the formula (1) preferably has 6 to 20 carbon atoms, more preferably 6 to 10 carbon atoms, and still more preferably 6 to 8 carbon atoms. The aryl group may have the following substituents.
Examples of the substituent include a hydroxy group, an alkoxy group, an acetyl group, a halogen atom, an alkyl group, and an aryl group.
In addition, the aryl group in R ¹ of the formula (1) is preferably —Ph—R ² . Ph represents a phenylene group, and R ² represents a hydrogen atom, an alkyl group, a hydroxy group, an alkoxy group, an acetyl group, or a halogen atom.

R ¹ in the formula (1) is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or —Ph—R ² , and preferably an alkyl group having 1 to 3 carbon atoms or —Ph—R ^2. Is more preferred and —Ph—R ² is even more preferred.
R ² is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, a hydroxy group, an alkoxy group having 1 or 2 carbon atoms, an acetyl group, or a halogen atom, and more preferably a hydrogen atom.

In the block (a), the proportion of the structural unit derived from the maleimide compound is 30% by mass or more based on the total mass of the block (a) from the viewpoint of storage stability and resistance to thermal cycle after curing. It is preferably 99% by mass, more preferably 30% by mass to 95% by mass, still more preferably 30% by mass to 90% by mass, and particularly preferably 40% by mass to 80% by mass. .

The styrene compound includes styrene and its derivatives. Specific compounds include styrene, α-methyl styrene, β-methyl styrene, vinyl toluene, vinyl xylene, vinyl naphthalene, o-methyl styrene, m-methyl styrene, p-methyl styrene, o-ethyl styrene, m- Ethyl styrene, p-ethyl styrene, pn-butyl styrene, p-isobutyl styrene, pt-butyl styrene, o-methoxy styrene, m-methoxy styrene, p-methoxy styrene, o-chloromethyl styrene, p- Examples include chloromethylstyrene, o-chlorostyrene, p-chlorostyrene, o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, divinylbenzene and the like, and one or more of these may be used. it can. By polymerizing a monomer containing a styrene compound, a structural unit derived from the styrene compound can be introduced into the block (a).
Among these, from the viewpoint of polymerizability, from the group consisting of styrene, α-methylstyrene, o-methoxystyrene, m-methoxystyrene, p-methoxystyrene, o-hydroxystyrene, m-hydroxystyrene, and p-hydroxystyrene. At least one selected compound is preferred.

Especially, the said block (a) has at least the structural unit represented by following formula (2) as a structural unit derived from the said styrene compound from a viewpoint of storage stability and the cold-heat cycle property after hardening. It is preferable.

In Formula (2), R ^S1 represents a hydrogen atom or a methyl group, R ^S2 independently represents an alkyl group, an alkoxy group, a hydroxy group, or a halogen atom, and sn represents an integer of 0 to 5.

R ^S2 in formula (2) is preferably each independently an alkyl group, an alkoxy group, a hydroxy group or a chlorine atom, and an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a hydroxy group or More preferably, it is a chlorine atom.
In formula (2), sn is preferably an integer of 0 to 2, more preferably 0 or 1, and particularly preferably 0.

In the block (a), the proportion of the structural unit derived from the styrene compound is 1% by mass to the total mass of the block (a) from the viewpoints of storage stability and cold cycle resistance after curing. It is preferably 70% by mass, more preferably 5% by mass to 70% by mass, still more preferably 10% by mass to 70% by mass, and particularly preferably 20% by mass to 60% by mass. .

The block (a) may have a structural unit derived from another monomer in addition to the structural unit derived from the maleimide compound and the structural unit derived from the styrene compound.
Examples of other monomers include (meth) acrylic acid ester compounds, amide group-containing vinyl compounds, amino group-containing vinyl compounds, unsaturated carboxylic acids, unsaturated acid anhydrides, and hydroxy group-containing vinyl compounds. These compounds may be used alone or in combination of two or more.
Among these, an amide group-containing vinyl compound is preferable from the viewpoint of compatibility with the 2-cyanoacrylate compound.
In the block (a), when having a structural unit derived from the other monomer, the proportion of the structural unit derived from the other monomer is 1 mass relative to the total mass of the block (a). % To 50% by mass, preferably 5% to 45% by mass, more preferably 10% to 40% by mass.

Specific examples of the (meth) acrylic acid alkyl ester compound include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, and (meth) acrylic acid n. -Butyl, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate (Meth) acrylic acid alkyl ester compounds such as n-nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate and dodecyl (meth) acrylate;
(Meth) acrylic acid cyclohexyl, (meth) acrylic acid methyl cyclohexyl, (meth) acrylic acid tert-butylcyclohexyl, (meth) acrylic acid cyclododecyl, (meth) acrylic acid isobornyl, (meth) acrylic acid adamantyl, (meth) Aliphatic cyclic ester compounds of (meth) acrylic acid such as dicyclopentenyl acrylate and dicyclopentanyl (meth) acrylate;
Methoxymethyl (meth) acrylate, ethoxymethyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, n-propoxyethyl (meth) acrylate, n-butoxy (meth) acrylate Ethyl, methoxypropyl (meth) acrylate, ethoxypropyl (meth) acrylate, n-propoxypropyl (meth) acrylate, n-butoxypropyl (meth) acrylate, methoxybutyl (meth) acrylate, (meth) acryl And (meth) acrylic acid alkoxyalkyl ester compounds such as ethoxybutyl acid, n-propoxybutyl (meth) acrylate, and n-butoxybutyl (meth) acrylate.

Examples of amide group-containing vinyl compounds include (meth) acrylamide, tert-butyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, and N-isopropyl (meth) acrylamide. , N, N-dimethylaminopropyl (meth) acrylamide and (meth) acrylamide derivatives such as (meth) acryloylmorpholine; and N-vinylamide series such as N-vinylacetamide, N-vinylformamide and N-vinylisobutyramide Examples include masses.

Examples of the amino group-containing vinyl compound include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate and N, N-dimethylaminopropyl (meth) acrylate.

Examples of unsaturated carboxylic acids include (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, citraconic acid, cinnamic acid, and monoalkyl esters of unsaturated dicarboxylic acids (maleic acid, fumaric acid, itaconic acid). Acid, citraconic acid, maleic anhydride, itaconic anhydride, monoalkyl esters such as citraconic anhydride) and the like. These compounds may be used alone or in combination of two or more.

Examples of the unsaturated acid anhydride include maleic anhydride, itaconic anhydride, citraconic anhydride, and the like.

Hydroxy group-containing vinyl compounds include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (meth ) 3-hydroxybutyl acrylate, 4-hydroxybutyl (meth) acrylate, and mono (meth) acrylates of polyalkylene glycols such as polyethylene glycol and polypropylene glycol.

The solubility parameter of the block (a) (SP value, unless otherwise specified (cal / cm ³ ) ^1/2 ) is 10. from the viewpoint of storage stability and oil resistance after curing. It is preferably 0 (cal / cm ³ ) ^1/2 or more, more preferably 11.0 (cal / cm ³ ) ^1/2 or more, and 12.0 (cal / cm ³ ) ^1/2 or more. More preferably. The upper limit of the SP value of the block (a) is not particularly limited, but is preferably 30 (cal / cm ³ ) ^1/2 or less.

For SP values in the present invention, R.D. F. It can be calculated by the calculation method described in “Polymer Engineering and Science” 14 (2), 147 (1974) written by Fedors. Specifically, it is based on the calculation method shown in Formula (3).

δ: SP value ((cal / cm ³ ) ^1/2 )
ΔEvap: heat of vaporization of each atomic group (cal / mol)
V: molar volume of each atomic group (cm ³ / mol)

-Block (b)-
The thermoplastic elastomer (B) used in the present invention has at least a block (b) having a glass transition temperature of 20 ° C. or lower.
The block (b) is not particularly limited as long as it has a Tg of 20 ° C. or less and can be synthesized, but is compatible with a 2-cyanoacrylate compound, storage stability, and resistance to cold and heat cycles after curing. From this point of view, an acrylic polymer block is preferable.
The acrylic polymer block in the present invention is a block containing 50% by mass or more of the structural unit derived from the acrylic compound with respect to the total mass of the block, and the structural unit derived from the acrylic compound is based on the total mass of the block. , Preferably a block containing 80% by mass or more, more preferably a block containing 90% by mass or more of a structural unit derived from an acrylic compound with respect to the total mass of the block, from a structural unit derived from an acrylic compound It is particularly preferable that the block is

The difference (absolute value) between the SP value of the block (a) and the SP value of the block (b) is 0.3 (cal / cm ³ ) ^1/2 or more from the viewpoint of the thermal cycle resistance after curing. It is preferably 0.5 (cal / cm ³ ) ^1/2 or more, more preferably 0.8 (cal / cm ³ ) ^1/2 or more, and 1.0 ( (cal / cm ³ ) ^1/2 or more is particularly preferable. Further, from the viewpoint of compatibility with the 2-cyanoacrylate compound, the difference between the SP value of the block (a) and the SP value of the block (b) is 5.0 (cal / cm ³ ) ^1/2 or less. Is preferred. It is 2.0455 (cal / cm ³ ) ^1/2 = 1 (cal / cm ³ ) ^1/2 = 1 MPa ^1/2 .

The acrylic polymer block can be obtained by polymerizing a monomer containing an acrylic monomer. An acrylic monomer refers to an unsaturated compound having an acryloyl group such as acrylic acid and an acrylic ester compound.
Examples of the acrylate compound include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, hexyl acrylate, and 2-ethylhexyl acrylate. Alkyl acrylate compounds such as octyl acrylate, nonyl acrylate, decyl acrylate, lauryl acrylate, stearyl acrylate;
Aliphatic cyclic ester compounds of acrylic acid such as cyclohexyl acrylate, methyl cyclohexyl acrylate, tert-butyl cyclohexyl acrylate, cyclododecyl acrylate;
Methoxymethyl acrylate, ethoxymethyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, n-propoxyethyl acrylate, n-butoxyethyl acrylate, methoxypropyl acrylate, ethoxypropyl acrylate, n-propoxypropyl acrylate And acrylic acid alkoxyalkyl ester compounds such as n-butoxypropyl acrylate, methoxybutyl acrylate, ethoxybutyl acrylate, n-propoxybutyl acrylate, and n-butoxybutyl acrylate. In addition, an acrylate compound having a functional group such as an amide group, an amino group, a carboxy group, or a hydroxy group may be used.
Among these, an alkyl acrylate ester compound having an alkyl group having 1 to 12 carbon atoms or an alkoxyalkyl group having 2 to 8 carbon atoms is preferable in that a block copolymer having excellent flexibility can be obtained. Further, from the viewpoint of compatibility with the 2-cyanoacrylate compound, the acrylic monomer includes an acrylic acid alkyl ester compound having an alkyl group having 1 to 3 carbon atoms or an alkoxyalkyl group having 2 to 3 carbon atoms. More preferably.

In the block (b), the proportion of the structural unit derived from the acrylic monomer is based on the total mass of the block (b) from the viewpoints of storage stability, thermal cycle resistance after curing and mechanical properties. On the other hand, it is preferably 20% by mass to 100% by mass, more preferably 50% by mass to 100% by mass, further preferably 80% by mass to 100% by mass, and 90% by mass to 100% by mass. % Is particularly preferred.

As long as the effects produced by the present invention are not hindered, the block (b) may contain a structural unit derived from a monomer other than the acrylic monomer.
As monomers other than acrylic monomers, monomers having unsaturated groups other than acryloyl groups can be used, methacryloyl group-containing compounds such as methacrylic acid esters, alkyl vinyl esters, alkyl vinyl ethers and Examples thereof include aliphatic or aromatic vinyl compounds such as styrene compounds.

Further, the SP value of the block (b) is preferably 9.5 (cal / cm ³ ) ^1/2 or more from the viewpoint of storage stability and resistance to cold and heat cycle after curing, and is 9.7. It is more preferable that it is (cal / cm ³ ) ^1/2 or more.
The SP value of the block (b) is preferably 20 (cal / cm ³ ) ^1/2 or less as the upper limit from the viewpoint of the development of thermoplasticity.

The content of the block (a) in the thermoplastic elastomer (B) is from 10% by mass to the total mass of the thermoplastic elastomer (B) from the viewpoints of storage stability and resistance to cold and heat cycle after curing. 60% by mass is preferable, and 20% by mass to 50% by mass is more preferable.
Moreover, content of the block (b) in the said thermoplastic elastomer (B) is 40 mass with respect to the total mass of a thermoplastic elastomer (B) from a viewpoint of storage stability and cold-heat cycle resistance after hardening. % To 90% by mass is preferable, and 50% to 80% by mass is more preferable.

The number average molecular weight (Mn) of the thermoplastic elastomer (B) is 10,000 to 500,000 from the viewpoints of compatibility with the 2-cyanoacrylate compound, viscosity of the composition, and strength after curing. It is preferably 20,000 to 400,000, more preferably 50,000 to 200,000.
The molecular weight distribution (Mw / Mn) obtained by dividing the value of the weight average molecular weight (Mw) of the thermoplastic elastomer (B) by the value of the number average molecular weight (Mn) is as follows. From the viewpoint of compatibility, it is preferably 1.5 or less, more preferably 1.4 or less, still more preferably 1.3 or less, and particularly preferably 1.2 or less. The lower limit of the molecular weight distribution is 1.0.
In addition, the value of the number average molecular weight (Mn) and the weight average molecular weight (Mw) of the resin in the present invention can be obtained by gel permeation chromatography (GPC) as described in Examples described later.

The content of the thermoplastic elastomer (B) in the adhesive composition of the present invention is such that the content of the 2-cyanoacrylate compound (A) is 100 parts by mass from the viewpoint of storage stability and resistance to cold and heat cycle after curing. On the other hand, it is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and still more preferably 10 parts by mass or more. Moreover, it is preferable that it is 100 mass parts or less from a viewpoint of an adhesion rate, a viscosity, etc.

<< Method for Producing Thermoplastic Elastomer (B) (Block Copolymer) >>
The thermoplastic elastomer (B) is not particularly limited as long as a block copolymer having at least the block (a) and the block (b) is obtained, and a known production method can be adopted. Examples thereof include a method using various controlled polymerization methods such as living radical polymerization and living anion polymerization, a method of coupling polymers having functional groups, and the like. Among these, the living radical polymerization method is preferable from the viewpoint of easy operation, application to a wide range of monomers, and storage stability, and the RAFT polymerization method described later is more preferable. . Since the thermoplastic elastomer (B) obtained by RAFT polymerization does not contain a heavy metal catalyst, the storage stability of the adhesive composition can be most enhanced.

Living radical polymerization may employ any process such as a batch process, a semi-batch process, a dry continuous polymerization process, or a continuous stirred tank process (CSTR). The polymerization method can be applied to various modes such as bulk polymerization without using a solvent, solvent-based solution polymerization, aqueous emulsion polymerization, miniemulsion polymerization or suspension polymerization.
There is no particular limitation on the type of living radical polymerization method, and reversible addition-cleavage chain transfer polymerization method (RAFT polymerization method), nitroxy radical method (NMP method), atom transfer radical polymerization method (ATRP method), organic tellurium Various polymerization methods such as a polymerization method using a compound (TERP method), a polymerization method using an organic antimony compound (SBRP method), a polymerization method using an organic bismuth compound (BIRP method), and an iodine transfer polymerization method can be employed. Among these, the RAFT polymerization method, the NMP method, and the ATRP method are preferable, and the RAFT polymerization method is more preferable from the viewpoint of controllability of polymerization and ease of implementation.

In the RAFT polymerization method, controlled polymerization proceeds through a reversible chain transfer reaction in the presence of a specific polymerization controller (RAFT agent) and a general free radical polymerization initiator. As the RAFT agent, various known RAFT agents such as a dithioester compound, a xanthate compound, a trithiocarbonate compound, and a dithiocarbamate compound can be used.
As the RAFT agent, a monofunctional agent having only one active site may be used, or a bifunctional or more functional agent may be used. From the viewpoint of efficiently obtaining the A- (BA) _n- type block copolymer, it is preferable to use a bifunctional RAFT agent.
Moreover, the usage-amount of a RAFT agent is suitably adjusted with the monomer to be used, the kind of RAFT agent, etc.

As the polymerization initiator used in the polymerization by the RAFT polymerization method, known radical polymerization initiators such as azo compounds, organic peroxides, and persulfates can be used. An azo compound is preferable because side reactions are less likely to occur.
Specific examples of the azo compound include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (4-methoxy-2, 4-dimethylvaleronitrile), dimethyl-2,2′-azobis (2-methylpropionate), 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1- Carbonitrile), 2,2′-azobis [N- (2-propenyl) -2-methylpropionamide], 2,2′-azobis (N-butyl-2-methylpropionamide), and the like.
The radical polymerization initiator may be used alone or in combination of two or more.

The proportion of the radical polymerization initiator used is not particularly limited, but from the viewpoint of obtaining a polymer having a smaller molecular weight distribution, the amount of the radical polymerization initiator used relative to 1 mol of the RAFT agent is preferably 0.5 mol or less. More preferably, it is 2 mol or less. From the viewpoint of stably performing the polymerization reaction, the lower limit of the amount of the radical polymerization initiator used relative to 1 mol of the RAFT agent is 0.01 mol. Therefore, the amount of radical polymerization initiator used per 1 mol of RAFT agent is preferably in the range of 0.01 mol to 0.5 mol, and more preferably in the range of 0.05 mol to 0.2 mol.

The reaction temperature during the polymerization reaction by the RAFT polymerization method is preferably 40 ° C. to 100 ° C., more preferably 45 ° C. to 90 ° C., and further preferably 50 ° C. to 80 ° C. If reaction temperature is 40 degreeC or more, a polymerization reaction can be advanced smoothly. On the other hand, if reaction temperature is 100 degrees C or less, while being able to suppress a side reaction, the restrictions regarding the initiator and solvent which can be used are eased.

In the NMP method, a specific alkoxyamine compound having nitroxide or the like is used as a living radical polymerization initiator, and polymerization proceeds via a nitroxide radical derived therefrom. In the present invention, the type of nitroxide radical to be used is not particularly limited, but from the viewpoint of polymerization controllability when polymerizing an acrylate-containing monomer, a compound represented by the formula (4) may be used as the nitroxide compound. preferable.

In the formula (4), R ^N1 represents an ethyl group, a methyl group or a hydrogen atom, R ^N2 represents an ethyl group, a methyl group or a nitrile group, R ^N3 represents — (CH ₂ ) _m —, and m represents 0 Represents an integer of ˜2, and R ^N4 and R ^N5 each independently represents an alkyl group having 1 to 4 carbon atoms.

The nitroxide compound represented by the formula (4) is primarily dissociated by heating at about 70 ° C. to 80 ° C. to cause an addition reaction with the vinyl monomer. In this case, it is possible to obtain a polyfunctional polymerization precursor by adding a nitroxide compound to a vinyl monomer having two or more vinyl groups. Next, the vinyl monomer can be living polymerized by secondary dissociation of the polymerization precursor under heating.
In this case, since the polymerization precursor has two or more active sites in the molecule, a polymer having a narrower molecular weight distribution can be obtained. From the viewpoint of easily obtaining the A- (BA) _n- type block copolymer, it is preferable to use a bifunctional polymerization precursor having two active sites in the molecule.
Moreover, the usage-amount of a nitroxide compound is suitably adjusted with the kind etc. of the monomer to be used and a nitroxide compound.

When the thermoplastic elastomer (B) is produced by the NMP method, the nitroxide radical represented by the formula (5) ranges from 0.001 mol to 0.2 mol with respect to 1 mol of the nitroxide compound represented by the formula (4). The polymerization may be carried out by adding in the above.

In formula (5), R ^N4 and R ^N5 each independently represent an alkyl group having 1 to 4 carbon atoms.

Addition of 0.001 mol or more of the nitroxide radical represented by the formula (5) shortens the time for the concentration of the nitroxide radical to reach a steady state. As a result, the polymerization can be controlled to a higher degree, and a polymer with a narrower molecular weight distribution can be obtained. On the other hand, if the amount of the nitroxide radical added is too large, the polymerization may not proceed. A more preferable addition amount of the nitroxide radical with respect to 1 mol of the nitroxide compound is in a range of 0.01 mol to 0.5 mol, and a more preferable addition amount is in a range of 0.05 mol to 0.2 mol.

The reaction temperature in the NMP method is preferably 50 ° C. to 140 ° C., more preferably 60 ° C. to 130 ° C., further preferably 70 ° C. to 120 ° C., and more preferably 80 ° C. to 120 ° C. Is particularly preferred. If reaction temperature is 50 degreeC or more, a polymerization reaction can be advanced smoothly. On the other hand, if the reaction temperature is 140 ° C. or lower, side reactions such as radical chain transfer tend to be suppressed.

In the ATRP method, a polymerization reaction is generally performed using an organic halide as an initiator and a transition metal complex as a catalyst. As the organic halide as an initiator, a monofunctional one or a bifunctional or higher one may be used. From the standpoint of efficiently obtaining the A- (BA) _n- type block copolymer, it is preferable to use a bifunctional compound. Moreover, as a kind of halide, a bromide or a chloride is preferable.

The reaction temperature in the ATRP method is preferably 20 ° C. to 200 ° C., more preferably 50 ° C. to 150 ° C. If the reaction temperature is 20 ° C. or higher, the polymerization reaction can proceed smoothly.

When an A- (BA) _n- type structure such as an ABA triblock copolymer comprising block (a) -block (b) -block (a) is obtained by living radical polymerization, each block is polymerized sequentially. In this case, the target block copolymer may be obtained, but it is preferable that the target block copolymer is obtained more efficiently when it is produced by a method including the following two-stage polymerization process. For example, as a first polymerization step, an acrylic monomer is polymerized to obtain an acrylic polymer block (block (b)), and then as a second polymerization step, 30% to 99% by weight of maleimide compound and styrene A monomer mixture containing 1% by mass to 70% by mass of the compound is polymerized to obtain the block (a). Thereby, an ABA triblock copolymer composed of block (a) -block (b) -block (a) can be obtained. According to this method, a process can be simplified compared with the case where each block is polymerized in sequence. Moreover, a higher order block copolymer such as a tetrablock copolymer can be obtained by repeating the first polymerization step and the second polymerization step.
When employing the production method including the first polymerization step and the second polymerization step, it is preferable to use the bifunctional polymerization initiator or the polymerization precursor as the polymerization initiator.

In this invention, you may implement superposition | polymerization of a block copolymer in presence of a chain transfer agent as needed irrespective of the polymerization method.
As the chain transfer agent, known ones can be used. Specifically, ethanethiol, 1-propanethiol, 2-propanethiol, 1-butanethiol, 2-butanethiol, 1-hexanethiol, 2-hexane Thiol, 2-methylheptane-2-thiol, 2-butylbutane-1-thiol, 1,1-dimethyl-1-pentanethiol, 1-octanethiol, 2-octanethiol, 1-decanethiol, 3-decanethiol, 1-undecanethiol, 1-dodecanethiol, 2-dodecanethiol, 1-tridecanethiol, 1-tetradecanethiol, 3-methyl-3-undecanethiol, 5-ethyl-5-decanethiol, tert-tetradecanethiol, 1 -Hexadecanethiol, 1-heptadecanethiol and 1- Other alkylthiol compound having an alkyl group having 2 to 20 carbon atoms such as Kuta decane thiol, mercaptoacetic acid, mercaptopropionic acid, 2-mercaptoethanol, and the like.
A chain transfer agent can use 1 type (s) or 2 or more types.

In the present invention, a known polymerization solvent can be used in living radical polymerization. Specifically, aromatic compounds such as benzene, toluene, xylene and anisole; ester compounds such as methyl acetate, ethyl acetate, propyl acetate and butyl acetate; ketone compounds such as acetone and methyl ethyl ketone; dimethylformamide, acetonitrile, dimethyl sulfoxide, Examples include alcohol and water. Moreover, you may carry out by aspects, such as block polymerization, without using a polymerization solvent.

<Other ingredients>
The adhesive composition of the present invention may contain other components other than the 2-cyanoacrylate compound (A) and the thermoplastic elastomer (B).
Other components include stabilizers, curing accelerators, plasticizers, thickeners, particles, colorants, fragrances, and the like conventionally used in adhesive compositions containing 2-cyanoacrylate. An appropriate amount of a solvent, a strength improver, or the like can be blended depending on the purpose within a range that does not impair the curability and adhesive strength of the adhesive composition.

Stabilizers include (1) aliphatic sulfonic acids such as sulfur dioxide and methanesulfonic acid, aromatic sulfonic acids such as p-toluenesulfonic acid, trifluoride such as boron trifluoride methanol and boron trifluoride diethyl ether. Examples include anionic polymerization inhibitors such as boron complexes, HBF ₄ , and trialkyl borates, and (2) radical polymerization inhibitors such as hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, catechol, and pyrogallol. These stabilizers may be used alone or in combination of two or more.

Any curing accelerator can be used as long as it promotes anionic polymerization of the 2-cyanoacrylate adhesive composition. Examples of the curing accelerator include polyether compounds, calixarenes, thiacalixallenes, pyrogallol allenes, and onium salts. These curing accelerators may be used alone or in combination of two or more.

Plasticizers include triethyl acetyl citrate, tributyl acetyl citrate, dimethyl adipate, diethyl adipate, dimethyl sebacate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisodecyl phthalate, dihexyl phthalate, phthalate Diheptyl acid, dioctyl phthalate, bis (2-ethylhexyl) phthalate, diisononyl phthalate, diisotridecyl phthalate, dipentadecyl phthalate, dioctyl terephthalate, diisononyl isophthalate, decyl toluate, bis (2-ethylhexyl) camphorate, 2 -Ethylhexyl cyclohexyl carboxylate, diisobutyl fumarate, diisobutyl maleate, triglyceride caproate, 2-ethylhexyl benzoate, dipropylene glycol Benzoate, and the like. Among these, tributyl acetyl citrate, dimethyl adipate, dimethyl phthalate, 2-ethylhexyl benzoate, and dipropylene glycol diethylene glycol are preferred because of their good compatibility with 2-cyanoacrylate compounds and high plasticization efficiency. Benzoate is preferred. These plasticizers may be used alone or in combination of two or more.

Thickeners include polymethyl methacrylate, copolymers of methyl methacrylate and acrylic esters, copolymers of methyl methacrylate and other methacrylate esters, acrylic rubber, polyvinyl chloride, polystyrene, cellulose esters And polyalkyl-2-cyanoacrylic acid ester and ethylene-vinyl acetate copolymer. These thickeners may be used alone or in combination of two or more.

The particles that may be blended in the adhesive composition are for adjusting the thickness of the adhesive layer when the adhesive composition is used.
The average particle diameter of the particles is preferably 10 μm to 200 μm, more preferably 15 μm to 200 μm, and still more preferably 15 μm to 150 μm.
The material of the particles is not particularly limited as long as it is insoluble in the 2-cyanoacrylate compound used and does not cause alteration such as polymerization. For example, thermoplastic resins such as polyethylene, polypropylene, polymethylpentene, polyvinyl chloride, polytetrafluoroethylene, polyethylene terephthalate, polybutylene terephthalate, polysulfone, and polyphenylene oxide; unsaturated polyester, divinylbenzene polymer, divinylbenzene-styrene copolymer Polymers, divinylbenzene- (meth) acrylic acid ester copolymers, crosslinked resins such as diallyl phthalate polymers; inorganic compounds such as spherical silica, glass beads and glass fibers; silicone compounds; organic polymer skeleton and polysiloxane skeleton And organic-inorganic composite particles.
Further, the content of the particles is not particularly limited, but when the content of the 2-cyanoacrylate compound is 100 parts by mass, it is preferably 0.1 parts by mass to 10 parts by mass, and 1 part by mass to 5 parts by mass. More preferably, it is more preferably 1 part by weight to 3 parts by weight. When the content is in the range of 0.1 to 10 parts by mass, the influence on the curing rate and the adhesive strength can be reduced.
The average particle diameter of the particles in the present invention is a volume-based average value measured by a laser diffraction particle size distribution measuring apparatus.

Hereinafter, the present invention will be specifically described based on examples. In addition, this invention is not limited by these Examples. In the following, “parts” and “%” mean “parts by mass” and “% by mass”, respectively, unless otherwise specified.
The SP value of the block in the thermoplastic elastomer was calculated by the method described above.

[1] Production of block copolymers A to J An analysis method for the polymers obtained in the production examples is described below.

<Molecular weight measurement>
The obtained polymer was subjected to gel permeation chromatography (GPC) measurement under the conditions described below to obtain a number average molecular weight (Mn) and a weight average molecular weight (Mw) in terms of polystyrene. Moreover, molecular weight distribution (Mw / Mn) was computed from the obtained value.
-Measurement condition-
Column: TSKgel SuperMultipore HZ-M x 4 manufactured by Tosoh Corporation Solvent: Tetrahydrofuran Temperature: 40 ° C
Detector: Differential refractometer (RI)
Flow rate: 600 μL / min

<Composition ratio of polymer>
The composition ratio of the obtained polymer was identified or calculated from ¹ H-NMR measurement.

<Glass transition temperature (Tg)>
The glass transition temperature (Tg) of the obtained polymer was determined from the intersection of the base line of the heat flux curve obtained using a differential scanning calorimeter and the tangent at the inflection point. The heat flux curve shows that about 10 mg of a sample was cooled to −50 ° C. and held for 5 minutes, then heated to 300 ° C. at 10 ° C./min, subsequently cooled to −50 ° C. and held for 5 minutes, then 10 ° C. / It was obtained under conditions where the temperature was raised to 350 ° C. in min.
Measuring instrument: DSC6220 manufactured by SII Nano Technology
Measurement atmosphere: under nitrogen atmosphere The polymer obtained in each production example was used as a sample for the Tg of the acrylic polymer block (b). Moreover, Tg of polymer block (a) is obtained (with Tg of acrylic polymer block (b)) by using the block copolymers obtained in Examples and Comparative Examples as samples.

<Synthesis of RAFT Agent: Synthesis of 1,4-bis (n-dodecylsulfanylthiocarbonylsulfanylmethyl) benzene>
To an eggplant-shaped flask, 1-dodecanethiol (42.2 g), 20% aqueous KOH solution (63.8 g), and trioctylmethylammonium chloride (1.5 g) were added, cooled in an ice bath, and carbon disulfide (15.9 g). ) And tetrahydrofuran (hereinafter also referred to as “THF”) (38 ml) were added and stirred for 20 minutes. A THF solution (170 ml) of α, α′-dichloro-p-xylene (16.6 g) was added dropwise over 30 minutes. After reacting at room temperature (25 ° C., the same applies hereinafter) for 1 hour, the mixture was extracted from chloroform, washed with pure water, dried over anhydrous sodium sulfate, and concentrated on a rotary evaporator. The obtained crude product is purified by column chromatography and then recrystallized from ethyl acetate to obtain 1,4-bis (n-dodecylsulfanylthiocarbonylsulfanylmethyl) benzene represented by the following formula (R). (Hereinafter also referred to as “DLBTTC”) was obtained in a yield of 80%. ^{From the 1} H-NMR measurement, the peak of the target product was confirmed at 7.2 ppm, 4.6 ppm, and 3.4 ppm.

<Manufacture of polymer 1>
In a 1 L flask equipped with a stirrer and a thermometer, the RAFT agent (DLBTC) (3.0 g) obtained in Synthesis Example 1 and 2,2′-azobis-2-methylbutyronitrile (hereinafter also referred to as “ABN-E”) .) (0.17 g), ethyl acrylate (EA, 456 g) and anisole (Anisole, 81.0 g) were sufficiently deaerated by nitrogen bubbling, and polymerization was started in a constant temperature bath at 60 ° C. After 3 hours and 30 minutes, the reaction was stopped by cooling to room temperature. The polymer solution obtained by stopping the reaction was purified by reprecipitation from hexane and dried in vacuo. The molecular weight of the obtained polymer 1 was Mn72,100, Mw78,600, and Mw / Mn was 1.09 from GPC (gel permeation chromatography) measurement (polystyrene conversion).

<Production of polymer 2>
In addition to ethyl acrylate, n-butyl acrylate (BA) was used, the amount of charge was changed as shown in Table 1, and the same operation as in the production of polymer 1 was carried out except that the reaction time was appropriately adjusted. A polymer 2 was obtained. The molecular weight of polymer 2 was measured and shown in Table 1. Further, the composition ratio of ethyl acrylate and n-butyl acrylate in the polymer was determined from ¹ H-NMR measurement and found to be ethyl acrylate / n-butyl acrylate = 25/75 (mass%). .

<Production of polymer 3>
Production of polymer 1 except that n-butyl acrylate and 2-ethylhexyl acrylate (HA) were used in place of ethyl acrylate, the charge was changed as shown in Table 1, and the reaction time was appropriately adjusted. The same operation as in Example 1 was performed to obtain a polymer 3. The molecular weight of the polymer 3 was measured and shown in Table 1. The composition ratio of n-butyl acrylate and 2-ethylhexyl acrylate in the polymer was determined from ¹ H-NMR measurement. As a result, n-butyl acrylate / 2-ethylhexyl acrylate = 76/24 (mass%) )Met.

<Production of polymer 4>
The amount of DLBTTC used was as shown in Table 1, and the same operation as in the production of the polymer 3 was performed except that the reaction time was appropriately adjusted, whereby the polymer 4 was obtained. The molecular weight of the polymer 4 was measured and shown in Table 1. Further, the composition ratio of n-butyl acrylate and 2-ethylhexyl acrylate in the polymer was determined from ¹ H-NMR measurement. As a result, n-butyl acrylate / 2-ethylhexyl acrylate = 75/25 (mass%) )Met.

<Production of polymer 5>
In place of ethyl acrylate, methyl acrylate (MA) was used, the charge was changed as shown in Table 1, and the reaction time was appropriately adjusted. Combined 5 was obtained. The molecular weight of the polymer 5 was measured and shown in Table 1.

<Production of polymer 6>
Polymer 6 was obtained in the same manner as in the production of polymer 3 except that the charge amount was changed as described in Table 1 and the reaction time was appropriately adjusted. The molecular weight of the polymer 6 was measured and shown in Table 1. The composition ratio of n-butyl acrylate and 2-ethylhexyl acrylate in the polymer was determined from ¹ H-NMR measurement. As a result, n-butyl acrylate / 2-ethylhexyl acrylate = 25/75 (mass%) Met.

In addition, the unit of each component composition in Table 1 is g.

<Production Example 1: Production of block copolymer A>
In a 1 L flask equipped with a stirrer and a thermometer, 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid (0.70 g), ABN-E (0.11 g), N-phenylmaleimide (PhMI 23.9 g), styrene (St, 14.4 g) and anisole (78.3 g) were charged, sufficiently deaerated by nitrogen bubbling, and polymerization was started in a constant temperature bath at 70 ° C. After 2 hours, after cooling to room temperature and stopping the reaction, ethyl acrylate (193.5 g) and anisole (30.2 g) were charged, sufficiently deaerated by nitrogen bubbling, and polymerization was started in a constant temperature bath at 70 ° C. . After 6 hours, anisole (120.5 g) was charged and cooled to room temperature to stop the reaction. Then, N-phenylmaleimide (28.7 g), styrene (18.7 g) and anisole (19.4 g) were charged, and nitrogen was added. Deaeration was sufficiently performed by bubbling, and polymerization was started in a constant temperature bath at 70 ° C. After 8 hours, anisole (171.7 g) was charged and the reaction was stopped by cooling to room temperature. A block copolymer A was obtained by reprecipitation purification from methanol and vacuum drying of the polymerization solution which stopped the reaction. As a result of measuring the molecular weight of the obtained block copolymer A, Mn86,500, Mw124,000, and Mw / Mn were 1.43.

Block copolymer A was a triblock copolymer having a structure of polymer block (a) -polymer block (b) -polymer block (a). The composition ratio of N-phenylmaleimide and styrene in the polymer block (a) was determined from ¹ H-NMR measurement. As a result, N-phenylmaleimide / styrene = 61/39 (mass%). The composition ratio of a) to the polymer block (b) was block (a) / block (b) = 32/68 (mass%).

<Production Example 2: Production of block copolymer B>
To a 1 L flask equipped with a stirrer and a thermometer, 2-{[(2-carboxyethyl) sulfanylthiocarbonyl] sulfanyl} propanoic acid (0.70 g), ABN-E (0.11 g), N-phenylmaleimide (24 0.0 g), styrene (12.3 g), α-methylstyrene (αMeSt, 2.5 g) and anisole (78.4 g) were charged, sufficiently deaerated by nitrogen bubbling, and polymerization was started in a constant temperature bath at 70 ° C. . After 4.5 hours, the reaction was stopped by cooling to room temperature, and then ethyl acrylate (97.8 g), butyl acrylate (49.0 g), 2-methoxyethyl acrylate (C-1, 49.0 g) and Anisole (29.3 g) was charged, sufficiently deaerated by nitrogen bubbling, and polymerization was started in a constant temperature bath at 70 ° C. After 4.5 hours, anisole (122.0 g) was charged and cooled to room temperature to stop the reaction, and then N-phenylmaleimide (28.8 g), styrene (15.9 g), α-methylstyrene (3.2 g) ) And anisole (19.4 g) were thoroughly deaerated by nitrogen bubbling, and polymerization was started in a constant temperature bath at 70 ° C. Ten hours later, anisole (167.7 g) was charged and the reaction was stopped by cooling to room temperature. The block copolymer B was obtained by reprecipitation refinement | purification and the vacuum drying of the polymerization solution which stopped reaction. As a result of measuring the molecular weight of the obtained block copolymer B, Mn76,600, Mw122,000, and Mw / Mn were 1.59.

Block copolymer B was a triblock copolymer having a structure of polymer block (a) -polymer block (b) -polymer block (a). The composition ratio of N-phenylmaleimide, styrene, and α-methylstyrene in the polymer block (a) was determined from ¹ H-NMR measurement. As a result, N-phenylmaleimide / styrene / α-methylstyrene = 61/32 The composition ratio of ethyl acrylate, butyl acrylate, and 2-methoxyethyl acrylate in the polymer block (b) was determined to be ethyl acrylate / butyl acrylate / acrylic. The acid 2-methoxyethyl was 50/25/25 (mass%). The composition ratio of the polymer block (a) to the polymer block (b) was block (a) / block (b) = 31/69 (mass%).

<Production Example 3: Production of block copolymer C>
In a 1 L flask equipped with a stirrer and a thermometer, polymer 1 (100.0 g), ABN-E (0.05 g), N-phenylmaleimide (27.0 g), styrene (17.7 g) and anisole (391 g) Was sufficiently deaerated by nitrogen bubbling, and polymerization was started in a thermostatic bath at 75 ° C. After 3 hours, the reaction was stopped by cooling to room temperature. A block copolymer C was obtained by reprecipitation purification from methanol and vacuum drying of the polymerization solution which stopped the reaction.

<Production Examples 4, 5, 6, 8 and 9: Production of block copolymers D, E, F, H and I>
While changing the kind and amount of raw materials charged into the flask as described in Table 2, the same operations as in Production Example 3 were carried out except that the reaction time was appropriately adjusted, and the block copolymers D, E, F, H and I was obtained respectively.

<Production Example 7: Production of block copolymer G>
A 1 L flask equipped with a stirrer and thermometer was charged with polymer 1 (100.0 g), ABN-E (0.05 g), isobornyl acrylate (IBXA, 92.0 g) and anisole (102 g), and nitrogen bubbling was sufficient. After deaeration, polymerization was started in a thermostatic chamber at 75 ° C. After 6 hours, the reaction was stopped by cooling to room temperature. The block solution G was obtained by reprecipitation purification from methanol and vacuum drying of the polymerization solution.

<Production Example 10: Production of block copolymer J>
In a 1 L flask equipped with a stirrer and a thermometer, polymer 1 (100.0 g), ABN-E (0.05 g), isobornyl acrylate (55.5 g), ethyl acrylate (EA, 17.8 g) and anisole ( 179 g) was sufficiently deaerated by nitrogen bubbling, and polymerization was started in a constant temperature bath at 75 ° C. After 6 hours, the reaction was stopped by cooling to room temperature. The copolymer solution was purified by reprecipitation from methanol and vacuum-dried to obtain a block copolymer J.

In addition, the unit of each component composition in Table 2 is g.

The molecular weights of the block copolymers A to J obtained by the production examples, and the polymer block (a) (block (a)) and polymer block (b) (block (b)) by ¹ H-NMR measurement Table 3 shows the composition ratio, SP value, Tg, and the composition ratio of the polymer block (a) and the polymer block (b) in the block copolymer.

[2] Production of 2-cyanoacrylate adhesive composition (Example 1)
Ethyl 2-cyanoacrylate was blended with 20 ppm sulfur dioxide and 1000 ppm hydroquinone to obtain an ethyl 2-cyanoacrylate blend. Next, 20 parts of the block copolymer A (100 parts of the ethyl 2-cyanoacrylate blend was blended) was stirred at 23 ° C. overnight and dissolved to prepare an adhesive composition.

(Examples 2 and 3 and Comparative Examples 1 to 3)
An adhesive composition was produced in the same manner as in Example 1 except that the block copolymer A was changed to the compounding agents shown in Table 4.

Abbreviations in the table other than the block copolymer indicate the following materials.
PMMA: polymethyl methacrylate, molecular weight 400,000, ASA: resin containing core-shell type rubber particles, manufactured by UMG ABS, trade name “Dialac S510”, acrylonitrile / butadiene / butyl acrylate / styrene copolymer

Example 4
Ethoxyethyl 2-cyanoacrylate was blended with 20 ppm sulfur dioxide and 1,000 ppm hydroquinone to obtain an ethoxyethyl 2-cyanoacrylate blend. Next, 20 parts of the block copolymer A (100 parts of the ethoxyethyl 2-cyanoacrylate compound was added) were mixed and stirred overnight at 23 ° C., and dissolved to prepare an adhesive composition.

(Examples 5 to 8 and Comparative Examples 4 and 5)
An adhesive composition was produced in the same manner as in Example 4 except that the block copolymer A was changed to the compounding agents shown in Table 5.

Abbreviations in the table other than the block copolymer indicate the following materials.
Vamac: Thermoplastic elastomer, manufactured by DuPont Elastomer, trade name “Vacac G”, ethylene / methyl acrylate / acrylic acid random copolymer

Example 9
Isobutyl 2-cyanoacrylate was blended with 20 ppm sulfur dioxide and 1,000 ppm hydroquinone. Next, 20 parts of block copolymer A (containing 100 parts of the isobutyl 2-cyanoacrylate compound) was blended, stirred overnight at 23 ° C., and dissolved to prepare an adhesive composition.

(Examples 10 to 14 and Comparative Examples 6 to 8)
An adhesive composition was produced in the same manner as in Example 9, except that the type of 2-cyanoacrylate, the type of block copolymer, and the blending amount thereof were changed to those shown in Table 6.

[3] Evaluation of 2-cyanoacrylate adhesive composition <Cooling and heat cycle resistance>
An aluminum plate (material defined in JIS A6061P) and a test piece made of ABS resin (made by Shin-Kobe Electric Machinery Co., Ltd., trade name “ABS-N-WN” as ABS resin) were used in Examples 1 to No. 14 or the adhesive composition of Comparative Examples 1 to 8, and allowed to stand at 23 ° C. for 3 days to cure, and then measured the tensile shear adhesive strength according to JIS K 6661 (this was the initial Strength). In Examples 1 to 3 and 9 to 14 and Comparative Examples 1 to 3 and 6 to 8, after adhesion curing, it was held at −20 ° C. for 1 hour using a thermal shock tester, and then held at 60 ° C. for 1 hour. The tensile shear bond strength after 10 cycles was measured in the same manner as described above, assuming that the cooling cycle to be performed was 1 cycle (this is the strength after the test), and the retention rate was calculated as follows. In Examples 4 to 8 and Comparative Examples 4 and 5, after the adhesive curing, the tensile shear after 10 cycles, with 1 cycle being the cold cycle of holding at −40 ° C. for 1 hour and then holding at 80 ° C. for 1 hour The adhesive strength was measured in the same manner as described above (this is the strength after the test), and the retention rate was calculated.
Retention rate (%) = (strength after test / initial strength) × 100

<Storage stability>
The adhesive composition was filled in a polyethylene (PE) container, sealed with an aluminum pack, and observed when left in a 60 ° C. environment.
A: The viscosity value of the composition after 7 days at 60 ° C. was changed within 3 times the initial value. B: The viscosity value of the composition after 7 days at 60 ° C. exceeded 3 times the initial value. It was a change

In Table 7, * marks indicate base material destruction of ABS resin test pieces.

According to the results in Table 7, Examples 1 to 3 had high initial tensile shear adhesive strength and tensile shear adhesive strength after the thermal cycle, and were excellent in storage stability of the adhesive composition. On the other hand, Comparative Examples 1 and 2 were peeled off during the thermal cycle test. Although Comparative Example 3 was not peeled off in the cooling and heating cycle test, the strength after the test was significantly reduced.

In Table 8, * marks indicate base material destruction of ABS resin test pieces.

According to the results of Table 8, Examples 4 to 8 showed a retention of 50% or more even in a cooling cycle test in a wider temperature range, and were excellent in the storage stability of the adhesive composition. . On the other hand, Comparative Example 4 was peeled off during the cold cycle test. Although Comparative Example 5 was not peeled off in the cooling and heating cycle test, the strength after the test was significantly reduced.

* In Table 9, * indicates ABS base material destruction.

According to the results in Table 9, Examples 9 to 14 had high initial tensile shear adhesive strength and tensile shear adhesive strength after the thermal cycle, and were excellent in storage stability of the adhesive composition. On the other hand, Comparative Examples 6 and 8 were peeled off during the cooling / heating cycle test. Although the comparative example 7 was not peeled off in the thermal cycle test, the strength after the test was significantly reduced.

The adhesive composition of the present invention contains a 2-cyanoacrylate compound and can be used as a so-called instantaneous adhesive in a wide range of products and technical fields such as general households and medical fields, as well as various industries. it can. In particular, it is useful for bonding automobile parts, electrical parts, electronic parts, and various footwear.
In addition, the adhesive composition of the present invention can be suitably used for adhesion between different types of adherends (for example, between a metal and a resin).

The disclosure of Japanese Patent Application No. 2017-087409 filed on Apr. 26, 2017 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards described in this specification are the same as if each document, patent application, and technical standard were specifically and individually stated to be incorporated by reference. Which is incorporated herein by reference.

Claims (10)

1. 2-cyanoacrylate compound (A), and
   Containing a thermoplastic elastomer (B),
   The thermoplastic elastomer (B) is a block copolymer having a block (a) and a block (b),
   The glass transition temperature of the block (a) is 80 ° C. or higher,
   A 2-cyanoacrylate adhesive composition, wherein the block (b) has a glass transition temperature of 20 ° C. or lower.
2. The 2-cyanoacrylate-based adhesive composition according to claim 1, wherein the block (a) has at least a structural unit derived from a maleimide compound.
3. The 2-cyanoacrylate adhesive composition according to claim 1 or 2, wherein the block (a) has at least a structural unit represented by the following formula (1).
   

   

   
   In the formula (1), R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or —Ph—R ² , Ph represents a phenylene group, R ² represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms , A hydroxy group, an alkoxy group having 1 or 2 carbon atoms, an acetyl group, or a halogen atom.
4. The 2-cyanoacrylate adhesive according to any one of claims 1 to 3, wherein the block (a) has at least a structural unit derived from a maleimide compound and a structural unit derived from a styrene compound. Composition.
5. The 2-cyanoacrylate adhesive composition according to any one of claims 1 to 4, wherein the solubility parameter of the block (a) is 10.0 (cal / cm ³ ) ^1/2 or more. object.
6. The 2-cyanoacrylate adhesive composition according to any one of claims 1 to 5, wherein the block (b) is an acrylic polymer block.
7. The 2-cyanoacrylate adhesive composition according to any one of claims 1 to 6, wherein the number average molecular weight of the thermoplastic elastomer (B) is 10,000 to 500,000.
8. The content of the thermoplastic elastomer (B) is 1 part by mass to 100 parts by mass with respect to 100 parts by mass of the content of the 2-cyanoacrylate compound (A). 2. The 2-cyanoacrylate adhesive composition according to item 1.
9. The 2-cyanoacrylate adhesive composition according to any one of claims 1 to 8, wherein the thermoplastic elastomer (B) is a block copolymer produced by a living radical polymerization method.
10. The 2-cyanoacrylate-based adhesive according to any one of claims 1 to 9, wherein the thermoplastic elastomer (B) is a block copolymer produced by a reversible addition-cleavage chain transfer polymerization method. Agent composition.