WO2018221564A1

WO2018221564A1 - Adhesive and structure

Info

Publication number: WO2018221564A1
Application number: PCT/JP2018/020704
Authority: WO
Inventors: 公二西口; 耀平大古田
Original assignee: 日立化成株式会社
Priority date: 2017-05-31
Filing date: 2018-05-30
Publication date: 2018-12-06
Also published as: TWI787274B; JPWO2018221564A1; CN110546223B; CN110546223A; TW201903102A

Abstract

One embodiment of the present invention relates to an adhesive comprising a polymer which includes a structural ethylene unit (A) having an aromatic ring group having two adjacent hydroxyl groups and a structural ethylene unit (B) having no aromatic ring group having two adjacent hydroxyl groups.

Description

Adhesives and structures

The present disclosure relates to an adhesive and a structure.

In recent years, adhesive materials that satisfy high demands such as adhesion, storage stability, rust prevention, heat resistance, and weather resistance have been demanded in various fields including the automobile field. In particular, with respect to adhesiveness, improvement of adhesive strength to difficult-to-adhere materials such as metal, glass and polyimide is required.

There are a wide variety of resins used as adhesives, such as acrylic resins, urethane resins, and epoxy resins (see, for example, Patent Documents 1 and 2).

Special Table 2007-521388 Japanese Patent Laying-Open No. 2015-229738

For example, acrylic resin is excellent in transparency and weather resistance, and demand is steadily increasing as an adhesive. However, depending on the application, the adhesive strength to metal, glass, polyimide, etc. was insufficient.

Therefore, the present disclosure provides an adhesive having excellent adhesive force. The present disclosure also provides a structure having excellent strength.

The present invention includes various embodiments. Examples of embodiments are listed below. The present invention is not limited to the following embodiments.

One embodiment is a polymer comprising an ethylene structural unit (A) having an aromatic ring group having two adjacent hydroxyl groups and an ethylene structural unit (B) not having an aromatic ring group having two adjacent hydroxyl groups The present invention relates to an adhesive containing

According to an embodiment, the proportion of the ethylene structural unit (A) contained in the polymer is 0.05 to 55 mol% based on the total of structural units other than the ethylene structural unit (A). preferable.

According to an embodiment, the polymer preferably has a weight average molecular weight of 70,000 or more.

According to one embodiment, the aromatic ring group having two adjacent hydroxyl groups preferably includes a group represented by the following formula (a1).

(In the formula, Ar represents an aromatic ring, R represents a substituent, l represents an integer of 0 or more, and represents the number of R. When l is 2 or more, a plurality of Rs are the same as each other. ("*" Represents a bonding position with another atom.)

According to one embodiment, the ethylene structural unit (A) preferably includes a structural unit represented by the following formula (A1).

(In the formula, A represents an aromatic ring group having two adjacent hydroxyl groups, X represents a divalent linking group, m represents an integer of 0 or 1, and R ^a1 to R ^a3 each independently represents hydrogen. Represents an atom or a substituent, and “*” represents a bonding position with another atom.)

According to one embodiment, the ethylene structural unit (B) preferably includes a structural unit represented by the following formula (B1).

(In the formula, R ^b1 to R ^b4 each independently represent a hydrogen atom or a substituent. “*” Represents a bonding position with another atom.)

According to one embodiment, the polymer is preferably a polymer represented by the following formula (P1).

(Where
A represents an aromatic ring group having two adjacent hydroxyl groups, X represents a divalent linking group, m represents an integer of 0 or 1, and R ^a1 to R ^a3 each independently represent a hydrogen atom or a substituent. Represents.
R ^b1 to R ^b4 each independently represents a hydrogen atom or a substituent.
“*” Represents a bonding position with another atom.
a and b satisfy 0.05 ≦ [a / b (mol / mol)] × 100 ≦ 55. )

According to one embodiment, the polymer includes an aromatic ring group having two adjacent hydroxyl groups and a monomer (A) having an ethylenically unsaturated group, and an aromatic ring group having two adjacent hydroxyl groups. It is preferable that it is a copolymer of the monomer containing the monomer (B) which has no ethylenically unsaturated group.

According to one embodiment, the adhesive may further contain a solvent.

Another embodiment includes an adherend (1), an adhesive layer, and an adherend (2), and the adherend (1) and the adherend (2) form the adhesive layer. And the adhesive layer contains any one of the adhesives.

According to one embodiment, the adherend (1) preferably includes at least one selected from the group consisting of stainless steel, copper, aluminum, magnesium, glass, and polyimide.

According to one embodiment, the adherend (2) preferably includes at least one selected from the group consisting of stainless steel, copper, aluminum, magnesium, glass, and polyimide.

According to the present disclosure, an adhesive having an excellent adhesive force is provided. Moreover, according to this indication, the structure which has the outstanding intensity | strength is provided.

FIG. 1 is a ¹ H-NMR spectrum of an adhesive polymer contained in the adhesive of Example 3.

An embodiment of the present invention will be described. The present invention is not limited to the following embodiments.
<Adhesive>
In one embodiment, the adhesive comprises an ethylene structural unit (A) having an aromatic ring group having two adjacent hydroxyl groups and an ethylene structural unit (B) having no aromatic ring group having two adjacent hydroxyl groups. (Hereinafter, this polymer may be referred to as “adhesive polymer”). The adhesive may contain arbitrary components such as a solvent and an additive.

[Adhesive polymer]
In one embodiment, the adhesive polymer includes an ethylene structural unit (A) and an ethylene structural unit (B). The adhesive polymer may have any structural unit other than the ethylene structural unit (A) and the ethylene structural unit (B).

(Ethylene structural unit (A))
The ethylene structural unit (A) is a structural unit having at least one aromatic ring group having an ethylene structure serving as a polymer skeleton and having two adjacent hydroxyl groups in the structural unit. An aromatic ring group is a substituent derived from an aromatic ring, and is bonded to the ethylene structure directly or via a divalent linking group. Examples of the aromatic ring include an aromatic hydrocarbon ring and an aromatic heterocyclic ring. The aromatic ring is preferably an aromatic hydrocarbon ring, and more preferably a benzene ring.

“Aromatic ring group having two adjacent hydroxyl groups” refers to an aromatic ring group in which hydrogen atoms bonded to two adjacent atoms constituting the aromatic ring are each substituted by a hydroxyl group (hereinafter, the aromatic group). The ring group may be referred to as a “dihydroxyaryl group”. Specifically, when the aromatic ring group is a phenyl group, it means a phenyl group in which each hydrogen atom bonded to two adjacent carbon atoms constituting the benzene ring is substituted with a hydroxyl group (hereinafter, the phenyl group). May be referred to as a “catechol group”). Examples include 2,3-dihydroxyphenyl group and 3,4-dihydroxyphenyl group. From the viewpoint of obtaining excellent adhesive strength, 3,4-dihydroxyphenyl group is preferred.

Examples of the dihydroxyaryl group include a group represented by the following formula (a1).

In the formula, Ar represents an aromatic ring, R represents a substituent, l is an integer of 0 or more, and represents the number of R. The upper limit of l is determined according to the structure of Ar. In the present disclosure, “*” represents a bonding position with another atom. The same applies hereinafter. When l is 2 or more, the plurality of R may be the same as or different from each other.
R is preferably a substituent other than a hydroxyl group, and examples thereof include an alkyl group having 1 to 4 carbon atoms.

Preferably, examples of the dihydroxyaryl group include a group represented by the following formula (a2).

In the formula, R represents a substituent, l is an integer of 0 to 3, and represents the number of R. l is preferably 0. When l is 2 or 3, a plurality of R may be the same as or different from each other.
R is preferably a substituent other than a hydroxyl group, and examples thereof include an alkyl group having 1 to 4 carbon atoms.

More preferably, examples of the dihydroxyaryl group include a group represented by the following formula (a3).

The dihydroxyaryl group is bonded to the ethylene structure directly or via a divalent linking group. Examples of the divalent linking group include a divalent group containing an amide bond (—NH—CO—) and a divalent group containing an ester bond (—O—CO—).

Examples of the divalent group include a group represented by the following formula (x1) and a group represented by the following formula (x2).

In the formula, n represents an integer of 0 to 10. From the viewpoint of improving adhesive strength, n is preferably 1 or more. Moreover, 6 or less is preferable from a viewpoint of suppressing adhesiveness, 4 or less is more preferable, and 3 or less is still more preferable.

Examples of the ethylene structural unit (A) include a structural unit represented by the following formula (A1).

In the formula, A represents a dihydroxyaryl group, X represents a divalent linking group, m represents an integer of 0 or 1, and R ^a1 to R ^a3 each independently represent a hydrogen atom or a substituent. The substituent is preferably a group other than a dihydroxyaryl group, and examples thereof include an alkyl group having 1 to 4 carbon atoms.

A is preferably a group represented by the formula (a1), more preferably a group represented by the formula (a2), and still more preferably a group represented by the formula (a3).
X is preferably a group represented by the formula (x1) or a group represented by the formula (x2), and more preferably a group represented by the formula (x1).
m is preferably 1.
R ^a1 and R ^a2 are preferably hydrogen atoms.
R ^a3 is preferably a hydrogen atom or a methyl group, and more preferably a methyl group.

(Ethylene structural unit (B))
An ethylene structural unit (B) is a structural unit which has an ethylene structure used as a polymer skeleton in a structural unit, and does not have a dihydroxyaryl group.

Examples of the ethylene structural unit (B) include a structural unit represented by the following formula (B1).

Wherein each ^represent R b1 ^{~ R b4} are independently a hydrogen atom or a substituent. The substituent is a group other than a dihydroxyaryl group. Examples of the substituent include an alkyl group having 1 to 4 carbon atoms, a monovalent group containing an ester bond, and a monovalent group containing an amide bond.

R ^b1 and ^{R b2} are preferably a hydrogen atom.
R ^b3 is preferably a hydrogen atom or a methyl group, and more preferably a methyl group.
R ^b4 is preferably a monovalent group containing an ester bond or a monovalent group containing an amide bond, an alkyloxycarbonyl group (R—O—CO— group (R is alkyl)), monoalkylaminocarbonyl Group (R—NH—CO— group (R is alkyl)) or dialkylaminocarbonyl group (R—NR′—CO— group (R and R ′ are alkyl)), preferably an alkyloxycarbonyl group or A dialkylaminocarbonyl group is more preferable, and an alkyloxycarbonyl group is still more preferable. The number of carbon atoms in the alkyl here is preferably 1 to 4.

(Ratio of structural units)
In one embodiment, from the viewpoint of improving adhesive strength, the ratio of the structural unit (A) is preferably 0.05 mol% or more based on the total of other structural units in the adhesive polymer. More preferably, it is 1 mol% or more, more preferably 1 mol% or more, and particularly preferably 1.5 mol% or more. Similarly, from the viewpoint of improving the adhesive strength, the ratio of the structural unit (A) is preferably 55 mol% or less with respect to the total of other structural units in the adhesive polymer, and is preferably 10 mol% or less. More preferably, it is more preferably 7.5 mol% or less, and particularly preferably 3 mol% or less. When the ratio of the structural unit (A) is within the above range, the adhesive force is easily improved. As one of the presumed reasons, when the ratio of the structural unit (A) is 55 mol% or less, the structural unit (which contributes to the improvement of the adhesive strength with the adherend due to the interaction in the polymer) It is mentioned that the substantial amount of A) increases. The ratio of the structural unit (A) can be determined by nuclear magnetic resonance spectroscopy (NMR spectroscopy). The “other structural unit” is a structural unit other than the structural unit (A).

(Weight average molecular weight)
According to one embodiment, from the viewpoint of improving adhesive strength, the weight average molecular weight is preferably 70,000 or more, more preferably 80,000 or more, and further preferably 100,000 or more. 120,000 or more is particularly preferable. Similarly, from the viewpoint of improving adhesive strength, the weight average molecular weight is preferably 200,000 or less, more preferably 180,000 or less, and still more preferably 160,000 or less.

(Number average molecular weight)
According to one embodiment, from the viewpoint of improving adhesive strength, the number average molecular weight is preferably 18,000 or more, more preferably 20,000 or more, and further preferably 25,000 or more. . Similarly, from the viewpoint of improving adhesive strength, the number average molecular weight is preferably 40,000 or less, more preferably 35,000 or less, and further preferably 33,000 or less.

(Dispersity (PDI = Mw / Mn))
According to one embodiment, from the viewpoint of improving adhesive strength, PDI is preferably 6 or less, more preferably 5 or less, and even more preferably 4 or less. Although a minimum is not specifically limited, Usually, it is 1 or more.

In the present disclosure, the weight average molecular weight and the number average molecular weight can be measured by size exclusion chromatography. Specifically, it can obtain | require by converting the measured value by a gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

(Specific examples of adhesive polymer)
In one embodiment, the adhesive polymer can be represented by the following formula (P1).

Where
A represents a dihydroxyaryl group, X represents a divalent linking group, m represents an integer of 0 or 1, and R ^1a to R ^3a each independently represents a hydrogen atom or a substituent.
R ^1b ~ ^{R 4b} each independently represents a hydrogen atom or a substituent.
a and b satisfy 0.05 ≦ [a / b (mol / mol)] × 100 ≦ 55.

The molar ratio [a / b] of the two structural units can be determined by nuclear magnetic resonance spectroscopy (NMR spectroscopy). Moreover, the terminal of an adhesive polymer is not specifically limited, Usually, the structure derived from a monomer, a polymerization initiator, etc. is contained.

From the viewpoint of obtaining high adhesive strength, 0.1 ≦ [a / b] is preferable, 1 ≦ [a / b] is more preferable, and 1.5 ≦ [a / b] is satisfied. Further preferred. Similarly, from the viewpoint of obtaining high adhesive strength, [a / b] ≦ 10 is preferable, [a / b] ≦ 7.5 is more preferable, and [a / b] ≦ 3. More preferably it is.

In one embodiment, the adhesive polymer includes a monomer (A) having a dihydroxyaryl group and an ethylenically unsaturated group, and a monomer (B) having no dihydroxyaryl group and having an ethylenically unsaturated group. ) -Containing monomer copolymer. A monomer (A), a monomer (B), etc. are mentioned later. The adhesive polymer may be a monomer copolymer composed of the monomer (A) and the monomer (B).

(Production method)
In one embodiment, the adhesive polymer is obtained by polymerizing at least two types of monomers having an ethylenically unsaturated group. The two types of monomers are a monomer (A) having a dihydroxyaryl group and an ethylenically unsaturated group, and a monomer (B) having no dihydroxyaryl group and having an ethylenically unsaturated group. Therefore, one embodiment of the method for producing an adhesive polymer includes copolymerizing a monomer containing the monomer (A) and the monomer (B).

The method for copolymerizing at least two types of monomers is not particularly limited. Methods such as radical polymerization, anionic polymerization, and cationic polymerization can be used. The polymerization method may be any of solution polymerization, suspension polymerization, emulsion polymerization and the like.

(Monomer (A))
There are at least two types of monomers having an ethylenically unsaturated group used in the method for producing an adhesive polymer, and one type of monomer is the monomer (A). The monomer (A) has at least one dihydroxyaryl group and at least one ethylenically unsaturated group in the molecule.

The dihydroxyaryl group is as described above. The monomer (A) may have an ethylenically unsaturated group as a “group containing an ethylenically unsaturated group”. Examples of the group containing an ethylenically unsaturated group include a vinyl group, an allyl group, and an acryloyl group. Methacryloyl group, acryloyloxy group, methacryloyloxy group, acrylamino group, and methacryloylamino group, and methacryloylamino group is preferable.

Examples of the monomer (A) include a vinyl compound having a catechol group, a (meth) acrylic acid ester compound having a catechol group, and a (meth) acrylamide compound having a catechol group.

Specific examples of the monomer (A) include compounds represented by the following formula (A2).

The symbols in the equation are as described in the equation (A1).

Preferably, examples of the monomer (A) include a compound (1) represented by the following formula.

(Monomer (B))
One other monomer among at least two monomers used in the method for producing an adhesive polymer is the monomer (B). The monomer (B) does not have a dihydroxyaryl group and has at least one ethylenically unsaturated group in the molecule. The dihydroxyaryl group and the ethylenically unsaturated group are as described above.

Specific examples of the monomer (B) include compounds represented by the following formula (B2).

The symbols in the formula are as described in the formula (B1).

Monomer (B) is, for example, styrene (vinyl benzene); acrylamide, methacrylamide; alkyl-substituted acrylamide or alkyl-substituted methacrylamide such as dimethylacrylamide and dimethylmethacrylamide; methyl acrylate, methyl methacrylate, ethyl acrylate, methacrylic acid Ethyl, n-butyl acrylate, n-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, t-butyl acrylate, t-butyl methacrylate, hexyl acrylate, hexyl methacrylate, 2-ethylhexyl acrylate, methacrylic acid Acrylic acid alkyl esters such as 2-ethylhexyl, n-octyl acrylate, n-octyl methacrylate, lauryl acrylate and lauryl methacrylate, and alkyl methacrylate Diacetone (meth) acrylamide; dicyclopentanyl (meth) acrylate; dicyclopentenyl (meth) acrylate; tetrahydrofurfuryl (meth) acrylate; benzyl (meth) acrylate; 1,2,2,6,6-penta Examples include methylpiperidinyl (meth) acrylate; 2,2,6,6-tetramethylpiperidinyl (meth) acrylate and the like.

As the monomer (B), a monomer containing a reactive functional group in the molecule can be used. Examples of the reactive functional group include a hydroxyl group, a carboxyl group, an epoxy group, and a halogen group. For example, as a monomer containing a reactive functional group, a compound in which a reactive functional group is substituted on the alkyl group of the above-mentioned alkyl-substituted acrylamide, alkyl-substituted methacrylamide, alkyl acrylate ester, or alkyl methacrylate ester can be given. Specific examples include (meth) acrylic acid esters having a hydroxyl group such as (meth) acrylic acid-2-hydroxyethyl and (meth) acrylic acid-4-hydroxybutyl.

Urethane (meth) such as a reaction product of tolylene diisocyanate and 2-hydroxyethyl (meth) acrylate, a reaction product of trimethylhexamethylene diisocyanate, cyclohexanedimethanol and 2-hydroxyethyl (meth) acrylate, etc. Acrylate may be used.

From the viewpoint of sufficiently obtaining the effect of the monomer (A), or from the viewpoint of obtaining excellent storage stability, the monomer (B) is composed of alkyl-substituted acrylamide, alkyl-substituted methacrylamide, alkyl acrylate ester, and alkyl methacrylate ester. It is preferable to include one or more selected, and more preferable to include one or more selected from alkyl-substituted methacrylamide and alkyl methacrylate. As the alkyl-substituted methacrylamide, dimethylacrylamide is preferable, and as the methacrylic acid alkyl ester, methyl methacrylate, n-butyl methacrylate and the like are preferable.

In one embodiment, the ratio of the monomer (A) used when synthesizing the adhesive polymer is 0.05 mol% or more with respect to the total of the monomers other than the monomer (A) in the monomer. preferable. Moreover, it is preferable that the ratio of a monomer (A) is 55 mol% or less with respect to the sum total of monomers other than the monomer (A) in a monomer. The adhesive polymer obtained by polymerizing the monomer composition containing the monomer (A) in the above range expresses higher adhesive strength to various adherends. From the viewpoint of adhesive strength, the ratio of the monomer (A) is more preferably 0.1 mol% or more, further preferably 1 mol% or more, and particularly preferably 1.5 mol% or more. . Similarly, the ratio of the monomer (A) is more preferably 10 mol% or less, further preferably 7.5 mol% or less, and particularly preferably 3 mol% or less.

In one embodiment, the total ratio of one or more selected from alkyl-substituted acrylamide, alkyl-substituted methacrylamide, alkyl acrylate, and alkyl methacrylate in monomer (B) is the total monomer (B), It is preferably 50 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol% or more. When the said range is satisfy | filled, the outstanding adhesive strength and storage stability are obtained. The upper limit can be 100 mol%.

(Radical polymerization initiator)
In obtaining the adhesive polymer, it is preferable to use a radical polymerization initiator in order to polymerize the monomer. The radical polymerization initiator is not particularly limited, and a normal radical polymerization initiator can be used. For example, azo compounds and peroxides are preferred. Specifically, azo radical initiators and organic peroxides that generate free radicals by heat are preferred.

Examples of the azo radical initiator include azobisisobutyronitrile (AIBN, trade name V-60, manufactured by Wako Pure Chemical Industries, Ltd.), 2,2′-azobis (2-methylisobutyronitrile). (Trade name V-59, manufactured by Wako Pure Chemical Industries, Ltd.), 2,2′-azobis (2,4-dimethylvaleronitrile) (trade name V-65, manufactured by Wako Pure Chemical Industries, Ltd.), dimethyl -2,2'-azobis (isobutyrate) (trade name V-601, manufactured by Wako Pure Chemical Industries, Ltd.), 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile) (trade name V -70, manufactured by Wako Pure Chemical Industries, Ltd.).

Examples of organic peroxides include isobutyl peroxide, α, α'-bis (neodecanoyl peroxyisopropyl) benzene, cumyl peroxyneodecanoate, di-n-propyl peroxydicarbonate, lauroyl peroxide. , Stearoyl peroxide, t-butylperoxybenzoate, n-butyl-4,4-bis (t-butylperoxy) valerate, di-t-butylperoxyisophthalate, α, α'-bis (t-butyl Peroxyisopropyl) benzene, cumene hydroperoxide, t-hexyl hydroperoxide, t-butyl hydroperoxide and the like.

The amount of radical polymerization initiator used can be appropriately selected according to the type of monomer, and is used in a general amount. Specifically, the content is preferably 0.01 to 2% by mass and more preferably 0.1 to 1% by mass with respect to the total amount of monomers.

(Reaction solvent)
When obtaining an adhesive polymer, it is preferably synthesized by solution polymerization using a reaction solvent. The reaction solvent is preferably an organic solvent, and the organic solvent is not particularly limited as long as the monomer dissolves. From the viewpoint of solubility of the monomer (A), it is preferable to use ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, or N, N-dimethylformamide (DMF).

The amount of the reaction solvent is not particularly limited, and may be determined from the viewpoint of polymerization rate, polymer molecular weight after polymerization, and the like. For example, when the polymer molecular weight (Mw) after polymerization is about 100,000, the total amount of monomers is preferably 15 to 60% by mass with respect to the solvent.

(Polymerization temperature)
The temperature at which the adhesive polymer is synthesized is not particularly limited and may be determined in consideration of the type of monomer used, the boiling point of the solvent, the half-life temperature of the polymerization initiator, and the like. For example, when polymerization is performed using azobisisobutyronitrile (AIBN) as a polymerization initiator, the reaction temperature is preferably 60 to 70 ° C.

(Post-processing)
When the adhesive polymer is obtained by solution polymerization, the adhesive polymer can be taken out as it is as a polymer solution after the reaction, but may be purified by precipitation. For example, the unreacted monomer remaining in the polymer solution can be removed by dropping the polymer solution after the reaction into a poor solvent for the adhesive polymer to obtain the adhesive polymer as a precipitate. Specifically, when two types of monomers, compound (1) and methyl methacrylate, are polymerized using N, N-dimethylformamide (DMF), the polymer solution is placed in water that becomes a poor solvent for the adhesive polymer after the reaction. It is possible to remove the unreacted monomer component by dropping and obtaining a precipitate.

However, the method for producing the adhesive polymer is not limited to the method described above. It is also possible to produce an adhesive polymer by a method of introducing a dihydroxyaryl group into a polymer containing an ethylene structural unit.

[Optional ingredients]
In addition to the adhesive polymer, the adhesive may contain any component such as a solvent, an additive, another polymer, and other adhesive components. The solvent is preferably an organic solvent, and specifically, the solvents mentioned as the reaction solvent can be used. Examples of the additive include an antioxidant, an ultraviolet absorber, a light stabilizer, a polymerization inhibitor, and a surfactant.

[Content]
There is no restriction | limiting in particular in content of the adhesive polymer in an adhesive agent. From the viewpoint of obtaining better adhesive strength, the content of the adhesive polymer is based on the total amount of the adhesive (however, when the adhesive includes a solvent, the total mass of the solid content excluding the mass of the solvent), for example, 80 to 100% by mass. When bonding an adherend using an adhesive, the adhesive preferably contains a solvent because the adhesive can be easily applied to the adherend by a coating method. In this case, the content of the adhesive polymer is, for example, 5 to 30% by mass based on the total amount of the adhesive (the total mass including the mass of the solvent).

[Adhesion method]
There is no restriction | limiting in particular about the adhesion | attachment method using an adhesive agent. For example, after applying an adhesive containing a solvent, it may be adhered by a method of drying the solvent, or may be adhered by a method of solidifying after applying and melting the adhesive by heating.

In one embodiment, the adhesive may be used for repair use, reinforcement use, or the like. Examples of objects used for repairing and reinforcing purposes include building floors, building materials such as walls, and concrete. Examples of the material to be used include metal, glass, plastic, and concrete.

<Structure>
In one embodiment, the structure includes an adherend (1), an adhesive layer, and an adherend (2), and the adherend (1) and the adherend (2) are interposed via the adhesive layer. And the adhesive layer contains the adhesive of the above embodiment. Since the adherend (1) and the adherend (2) are bonded to each other with an adhesive having high adhesive strength, the structure has excellent strength.

Examples of adherend (1) and adherend (2) include metal, glass, plastic, and concrete, and the types of metal, glass, plastic, and concrete are not particularly limited. Examples of the plastic include engineering plastics such as polyimide, polyamideimide, and polyamide. Either or both of the adherend (1) and the adherend (2) may be at least one selected from the group consisting of stainless steel, copper, aluminum, magnesium, glass, and polyimide. .

The structure can be obtained using, for example, an adhesive containing a solvent. According to one embodiment, the structure is formed by applying an adhesive to both the adherend (1) and the adherend (2), or one of the adherend (A) and the adherend ( It can be produced by bonding B) and removing the solvent. Examples of the coating method include a potting method, a dipping method, a spray method, and a roll coating method. Examples of the solvent removal include a method of drying by heating, reduced pressure, a combination thereof or the like.

Examples of structures include automobile parts, household appliance parts, display devices, portable terminals, electronic parts, building materials, concrete, and the like.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

<Production and Evaluation 1 of Adhesive>
Adhesives containing an adhesive polymer were prepared and evaluated for adhesive strength and storage stability.

[Synthesis of adhesive polymer]
The adhesive polymer was synthesized by changing the ratio of the monomer (A) and the monomer (B), and the molecular weight and composition ratio were determined.
Example 1
In a 50 mL two-necked eggplant type flask, 100 mg of compound (1) ((N- (3,4-dihydroxyphenylethyl) methacrylamide)), 75 mg of azobisisobutyronitrile (AIBN), and a rotor were placed. A reflux tube and a nitrogen inlet tube were attached. After deaeration of the system and replacement with nitrogen, 9.1 g of methyl methacrylate (MMA) and 17.0 g of N, N-dimethylformamide (DMF) were added, and the mixture was stirred at 100 rpm using a magnetic stirrer. 1) and AIBN were dissolved. Nitrogen was introduced at 20 mL / min, and after bubbling for 30 minutes, the nitrogen introduction tube was raised from the liquid level, nitrogen introduction was continued, and the temperature was raised to 65 ° C. The reaction was started when the temperature reached 65 ° C., and the reaction was continued for 10 hours. Then, in order to deactivate AIBN, the temperature was raised to 75 ° C. and held for 30 minutes, and then cooled to room temperature to obtain a polymer solution. 1,000 g of pure water was put into a 2 L beaker, and the polymer solution was dropped into water using a dropping funnel while stirring and putting a rotor. After stirring for 30 minutes, the precipitate was collected by filtration and dried at 80 ° C. for 8 hours to obtain a solid adhesive polymer in a yield of 92% by mass.

(Measurement of molecular weight of adhesive polymer)
0.05 g of the adhesive polymer was dissolved in 5 g of tetrahydrofuran (THF), and gel permeation chromatography (“CHROMASTER” manufactured by Hitachi High-Technologies Corporation), columns: GL-A130S, GL-A150S, GL-A160 (3-connected, (All manufactured by GL Sciences Inc.), detector: RI, eluent: THF, flow rate: 1.0 mL / min, column temperature: 35 ° C., injection amount: 70 μL), weight average molecular weight, number average of adhesive polymer Molecular weight and molecular weight distribution (Mw / Mn) were measured. The results are shown in Table 1.

(Composition analysis of adhesive polymer)
10 mg of adhesive polymer is dissolved in 0.8 mL of deuterated dimethyl sulfoxide, nuclear magnetic resonance apparatus (“AV400M” manufactured by Bruker BioSpin Co., Ltd., frequency: 400 MHz, integration frequency: 16, temperature: 25 ° C., reference substance : Tetramethylsilane (TMS)) was used for ¹ H-NMR measurement. From the proton ratio of the obtained spectrum, the ratio of structural units contained in the adhesive polymer was calculated. The results are shown in Table 1.

(Example 2)
In the synthesis of the adhesive polymer, the adhesive polymer was synthesized in the same manner as in Example 1 except that the compound (1) was 200 mg, AIBN 75 mg, MMA 9.1 g, and DMF 17.2 g, and the molecular weight and composition ratio were determined. The yield was 86% by mass.

(Example 3)
In the synthesis of the adhesive polymer, the adhesive polymer was synthesized in the same manner as in Example 1 except that the compound (1) was 400 mg, AIBN 76 mg, MMA 9.1 g, and DMF 17.6 g, and the molecular weight and composition ratio were determined. The yield was 89% by mass. FIG. 1 shows the ¹ H-NMR spectrum.

Example 4
In the synthesis of the adhesive polymer, the adhesive polymer was synthesized in the same manner as in Example 1 except that the compound (1) was 900 mg, AIBN 70 mg, MMA 8.1 g, and DMF 16.8 g, and the molecular weight and composition ratio were determined. The yield was 83% by mass.

(Example 5)
In the synthesis of the adhesive polymer, the adhesive polymer was synthesized in the same manner as in Example 1 except that the compound (1) was 1.7 g, AIBN 69 mg, MMA 7.7 g, and DMF 17.4 g, and the molecular weight and composition ratio were determined. It was. The yield was 83% by mass.

(Example 6)
In the synthesis of the adhesive polymer, the adhesive polymer was synthesized in the same manner as in Example 1 except that the compound (1) was 5.0 g, AIBN 56 mg, MMA 4.5 g, and DMF 17.7 g, and the molecular weight and composition ratio were obtained. It was. The yield was 93% by mass.

(Comparative Example 1)
In the synthesis of the adhesive polymer, an adhesive polymer was synthesized in the same manner as in Example 1 except that 62 mg of AIBN, 7.5 g of MMA, and 14.5 g of DMF were used, and the molecular weight and the composition ratio were determined. The yield was 84% by mass.

(Comparative Example 2)
In the synthesis of the adhesive polymer, an adhesive polymer was synthesized in the same manner as in Example 1 except that the compound (1) was 6.0 g, AIBN 22 mg, and DMF 11.1 g. The yield was 84% by mass. Since the adhesive polymer was not dissolved in tetrahydrofuran, the molecular weight could not be measured.

(Comparative Example 3)
In the synthesis of the adhesive polymer, the adhesive polymer was synthesized in the same manner as in Example 1 except that AIBN was 115 mg, MMA 13.9 g, acrylic acid (AA) 100 mg, and DMF 26.0 g, and the molecular weight and composition ratio were determined. . The yield was 84% by mass.

[Evaluation of adhesive strength]
The adhesive strengths of the adhesive polymers (adhesives) of Examples 1 to 6 and Comparative Examples 1 to 3 were evaluated. The results are shown in Table 1.

(Preparation of polymer solution)
Into a 20 cc sample tube, 1.5 g of the prepared adhesive polymer and 10 g of ethyl acetate are put, and ultrasonic irradiation is performed for 10 minutes, and then mixed for 30 minutes using a mix rotor, and a polymer solution having a solid content of 15% by mass (application) Adhesive).

(Preparation of test piece)
Each surface of a metal substrate (stainless steel (SUS304), copper, aluminum, magnesium) having a size of 20 mm × 70 mm and a thickness of 1 mm, and a glass substrate (float glass) having a size of 20 mm × 70 mm and a thickness of 8 mm, Acetone was poured to wash and dry thoroughly.
To one end of each substrate (metal substrate: 20 mm × 10 mm, glass substrate: 20 mm × 5 mm), 0.1 mL of a polymer solution prepared using a micropipette was dropped, and the liquid level was smoothed with a glass rod. Two base materials coated with the polymer solution for each type of base material were prepared, and after leaving for 10 minutes in a dryer at 80 ° C. to remove the solvent, the two base materials were coated with the polymer solution. They were superposed so that they were bonded together, fixed with clips, and allowed to stand in a dryer at 180 ° C. for 2 hours to obtain test pieces for evaluation of shear bond strength.
The adhesion width of the metal substrate was 10 mm, and the adhesion width of the glass substrate was 5 mm. In all the substrates, the thickness of the adhesive layer was about 60 μm.

(Evaluation of tensile shear bond strength)
A test piece prepared on an autograph tester (“AUTOGRAPH AGS-X” manufactured by Shimadzu Corporation) is attached, and the tensile speed is 10 mm / min, the angle is 180 ° (direction parallel to the bonding surface), and the temperature is 23 ° C. Tensile shear bond strength was measured.

In the measurement of the tensile shear adhesive strength using the metal substrates of Examples 1 to 6, cohesive failure occurred. In the measurement using the glass substrate of Examples 1 to 6, the substrate was broken. Further, in the measurements of Comparative Examples 1 to 3, the interface fracture occurred in any of the substrates.

As shown in Examples 1 to 6, the adhesive polymer containing the structural unit (A) and the structural unit (B) greatly improved the adhesion strength to various metals and glasses. In particular, the adhesive polymer having the structural unit (A) ratio of 2 mol% has the highest adhesive strength.

On the other hand, as shown in Comparative Examples 1 to 3, the adhesive polymer containing only the structural unit (A) (Comparative Example 2) and the adhesive polymer containing only the structural unit (B) (Comparative Examples 1 and 3) The adhesive strength was small.

[Evaluation of storage stability]
The storage stability of the adhesive polymers of Examples 2, 3 and 5 and Comparative Examples 1 to 3 was evaluated. The evaluation was performed by allowing the adhesive polymer to stand according to the

following condition

1 or 2 and then analyzing the composition ratio and comparing the composition ratio before and after standing. The results are shown in Table 2. It can be said that an adhesive polymer having a small variation in composition ratio is excellent in storage stability.

(Condition 1: Evaluation of heat resistance)
1 g of the produced adhesive polymer was put in a sample tube and allowed to stand at 60 ° C. for 30 days. After standing, the composition of the adhesive polymer was analyzed according to the method described above.
(Condition 2: Evaluation of solvent resistance)
The polymer solution prepared in the same manner as described above was allowed to stand at room temperature (25 ° C.) for 30 days. After standing, ethyl acetate as a solvent was removed by an evaporator, and vacuum-dried at 40 ° C. for 12 hours to recover an adhesive polymer. After recovery, the composition of the adhesive polymer was analyzed according to the method described above.

As shown in Table 2, the compositions of the adhesive polymers of Examples 2, 3 and 5 did not change after standing. According to the adhesive polymer containing the structural unit (A) and the structural unit (B), both high adhesive strength and excellent storage stability can be achieved.

On the other hand, the adhesive polymer of Comparative Example 3 was thought to have changed structure due to having a carboxyl group, and the proton ratio could not be accurately calculated in ¹ H-NMR analysis, making it impossible to analyze the composition.

<Production and Evaluation 2 of Adhesive>
An adhesive containing an adhesive polymer was prepared, and the adhesive strength was evaluated.

[Synthesis of adhesive polymer]
The amount of radical polymerization initiator used was changed to synthesize an adhesive polymer, and the molecular weight and composition ratio were determined.
(Example 7)
In the synthesis of the adhesive polymer, the adhesive polymer was synthesized in the same manner as in Example 1 except that the compound (1) was 400 mg, AIBN 28 mg, MMA 9.1 g, and DMF 17.6, and the molecular weight and composition ratio were determined. The yield was 86% by mass.

(Example 8)
In the synthesis of the adhesive polymer, the adhesive polymer was synthesized in the same manner as in Example 1 except that the compound (1) was 400 mg, AIBN 15 mg, MMA 9.1 g, and DMF 17.6 g, and the molecular weight and composition ratio were determined. The yield was 84% by mass.

[Evaluation of adhesive strength]
For the adhesive polymers (adhesives) of Examples 7 and 8, the adhesive strength was measured in the same manner as in Example 1. The results are shown in Table 3 together with the results of Example 3.

As shown in Table 3, the adhesive polymers of Examples 7 and 8 also showed high adhesive strength. In particular, the highest adhesive strength was obtained in the adhesive polymer of Example 7.

<Production and Evaluation of Adhesive 3>
An adhesive containing an adhesive polymer was prepared, and the adhesive strength was evaluated.

[Synthesis of adhesive polymer]
The type of monomer (B) was changed, an adhesive polymer was synthesized, and the molecular weight and composition ratio were determined.
Example 9
In the synthesis of the adhesive polymer, the adhesive polymer was synthesized in the same manner as in Example 1 except that the compound (1) was 400 mg, AIBN 75 mg, n-butyl methacrylate (BMA) 12.8 g, and DMF 17.6 g. The composition ratio was determined. The yield was 89% by mass.

(Comparative Example 4)
In the synthesis of the adhesive polymer, the adhesive polymer was synthesized in the same manner as in Example 1 except that AIBN was 75 mg, BMA 10.0 g, and DMF 18.6 g, and the molecular weight and composition ratio were determined. The yield was 88% by mass.

[Evaluation of adhesive strength]
For the adhesive polymers (adhesives) of Example 9 and Comparative Example 4, the adhesive strength was evaluated in the same manner as in Example 1. The results are shown in Table 4 together with the results of the adhesive polymer of Example 3.

As shown in Table 4, the adhesive polymer of Example 9 also showed high adhesive strength.

<Production and Evaluation of Adhesive 4>
The adhesive strength of the adhesive containing the adhesive polymer to the plastic was evaluated.

[Evaluation of adhesive strength]
About the polymer (adhesive agent) produced in Example 9 and Comparative Example 4, the adhesive strength to a polyimide base material was evaluated. The results are shown in Table 5.

(Preparation of polymer solution)
1 g of the polymer prepared in Example 9 and 4 g of methyl ethyl ketone were mixed using a mix rotor to obtain a polymer solution (adhesive for application).
(Preparation of test piece)
The polymer solution was applied to a polyimide film (“Kapton 200EN” manufactured by Toray DuPont Co., Ltd.) using a 100 μm applicator. After drying with an 80 ° C. dryer for 1 hour, the temperature was returned to room temperature to obtain a test piece.
(Cross cut test)
The adhesive layer of the test piece was cut into a cloth with a cutter to form 100 squares (1 mm × 1 mm). Cellophane tape was applied to 100 squares and peeled off at a stretch, and the presence or absence of peeling of the squares was confirmed (number of squares not peeled / 100 squares).

As shown in Table 5, the adhesive polymer containing the structural unit (A) and the structural unit (B) greatly improved the adhesive strength to polyimide.

From the above results, it can be seen that the adhesive polymer containing the structural unit (A) and the structural unit (B) exhibits excellent adhesive strength.

The disclosure of the present application is related to the subject matter described in Japanese Patent Application No. 2017-108374 filed on May 31, 2017, the entire disclosure of which is incorporated herein by reference.

Claims

An adhesive comprising a polymer comprising an ethylene structural unit (A) having an aromatic ring group having two adjacent hydroxyl groups and an ethylene structural unit (B) having no aromatic ring group having two adjacent hydroxyl groups Agent.
The adhesive according to claim 1, wherein a ratio of the ethylene structural unit (A) contained in the polymer is 0.05 to 55 mol% based on a total of structural units other than the ethylene structural unit (A). .
The adhesive according to claim 1 or 2, wherein the polymer has a weight average molecular weight of 70,000 or more.
The adhesive according to any one of claims 1 to 3, wherein the aromatic ring group having two adjacent hydroxyl groups includes a group represented by the following formula (a1).

(In the formula, Ar represents an aromatic ring, R represents a substituent, l represents an integer of 0 or more, and represents the number of R. When l is 2 or more, a plurality of Rs are the same as each other. ("*" Represents a bonding position with another atom.)
The adhesive according to any one of claims 1 to 4, wherein the ethylene structural unit (A) includes a structural unit represented by the following formula (A1).

(In the formula, A represents an aromatic ring group having two adjacent hydroxyl groups, X represents a divalent linking group, m represents an integer of 0 or 1, and R a1 to R a3 each independently represents hydrogen. Represents an atom or a substituent, and “*” represents a bonding position with another atom.)
The adhesive according to any one of claims 1 to 5, wherein the ethylene structural unit (B) includes a structural unit represented by the following formula (B1).

(In the formula, R b1 to R b4 each independently represent a hydrogen atom or a substituent. “*” Represents a bonding position with another atom.)
The adhesive according to any one of claims 1 to 6, wherein the polymer is represented by the following formula (P1).

(Where
A represents an aromatic ring group having two adjacent hydroxyl groups, X represents a divalent linking group, m represents an integer of 0 or 1, and R a1 to R a3 each independently represent a hydrogen atom or a substituent. Represents.
R b1 to R b4 each independently represents a hydrogen atom or a substituent.
“*” Represents a bonding position with another atom.
a and b satisfy 0.05 ≦ [a / b (mol / mol)] × 100 ≦ 55. )
The polymer has an aromatic ring group having two adjacent hydroxyl groups and a monomer (A) having an ethylenically unsaturated group, and has no aromatic ring group having two adjacent hydroxyl groups, and is ethylenic. The adhesive according to any one of claims 1 to 7, which is a copolymer of monomers containing a monomer (B) having an unsaturated group.
The adhesive according to any one of claims 1 to 8, further comprising a solvent.
An adherend (1), an adhesive layer, and an adherend (2) are provided, and the adherend (1) and the adherend (2) are bonded via the adhesive layer, A structure in which the adhesive layer contains the adhesive according to any one of claims 1 to 9.
The structure according to claim 10, wherein the adherend (1) includes at least one selected from the group consisting of stainless steel, copper, aluminum, magnesium, glass, and polyimide.
The structure according to claim 10 or 11, wherein the adherend (2) includes at least one selected from the group consisting of stainless steel, copper, aluminum, magnesium, glass, and polyimide.