WO2020085335A1 - Production method for 2-cyanoacrylate compound and production method for photocurable adhesive composition - Google Patents

Abstract

This production method for a 2-cyanoacrylate compound includes: a depolymerization step for depolymerizing a 2-cyanoacrylate polycondensate that is a condensate of a cyanoacetic acid ester compound and a formaldehyde compound in the presence of a polymerization inhibitor and under heat and reduced pressure to obtain a crude 2-cyanoacrylate monomer; and a distillation purification step for distilling the crude 2-cyanoacrylate monomer to obtain a purified 2-cyanoacrylate monomer. The polymerization inhibitor used in the depolymerization step is a compound that does not have a hydroquinone structure.

Description

Method for producing 2-cyanoacrylate compound and method for producing photocurable adhesive composition

The present invention relates to a method for producing a 2-cyanoacrylate compound and a method for producing a photocurable adhesive composition.

The 2-cyanoacrylate compound rapidly starts polymerization due to a small amount of water existing near the surface of the adherend, and adheres almost all adherends made of various materials in an extremely short time of several seconds to several minutes. Since it has a strong adhesive force, it is used as a main component of an instant adhesive in a wide range of fields such as electric, electronic, mechanical parts, precision machinery, household products and medical care.

As a conventional method for producing a 2-cyanoacrylate compound, the methods described in Patent Documents 1 to 4 are known.
In Patent Document 1, in a method for producing 2-cyanoacrylate by depolymerizing a condensate of cyanoacetate and formaldehyde, the concentration of a depolymerization catalyst in a reaction solution in a depolymerization reactor having a stirrer is adjusted during the reaction. There is described a method for producing 2-cyanoacrylate, which is characterized by carrying out a depolymerization reaction while keeping it constant.

Further, in Patent Document 2, in depolymerizing a condensate of cyanoacetate and formaldehyde in the presence of a polymerization inhibitor, a high-boiling point fraction condensed from the fraction obtained by depolymerization at a boiling point of 2-cyanoacrylate or higher. A method for producing 2-cyanoacrylate is described, which comprises depolymerizing by returning the components to the depolymerization reaction.

Further, Patent Document 3 discloses a method for producing 2-cyanoacrylate, which comprises a step of depolymerizing a condensate of cyanoacetate and formaldehyde, and a step of distilling and purifying the obtained crude 2-cyanoacrylate. A method for producing 2-cyanoacrylate, characterized in that the temperature of the dephlegmator in the step is 10 ° C. or more higher than the boiling point of 2-cyanoacrylate at that pressure and the high-boiling acid component is decondensed and removed at 50 ° C. or less. Have been described.

Further, in Patent Document 4, a step of introducing a cyanoacetic acid ester and formalin into a reaction tank to carry out a polycondensation reaction, a step of introducing the obtained polycondensation reaction solution into a dehydration tank to dehydrate, and a dehydrated polycondensation The step of continuously introducing the reaction solution into the thin film evaporator for desolvation and the step of continuously introducing the decondensed polycondensate into the thin film evaporator for depolymerization are carried out continuously. The dehydration tank is divided into two or more dehydration tanks connected in series, and after introducing the polycondensation reaction solution into the first dehydration tank of the dehydration tanks connected in series, a solvent is added to carry out azeotropic dehydration. The continuous production method of 2-cyanoacrylate is described.

Patent Document 1: Japanese Patent No. 3475780 Patent Document 2: Japanese Patent No. 3804396 Patent Document 3: Japanese Patent No. 3965909 Patent Document 4: Japanese Patent No. 5311272

The problem to be solved by the present invention is a 2-cyanoacrylate compound capable of improving the storage stability of a photocurable adhesive composition containing a Group 8 transition metal metallocene compound and a 2-cyanoacrylate compound. Is to provide a method for manufacturing the same.
Another problem to be solved by the present invention is to provide a method for producing a photocurable adhesive composition using a 2-cyanoacrylate compound obtained by the method for producing a 2-cyanoacrylate compound.

Means for solving the above problems include the following aspects.
<1> A 2-cyanoacrylate polycondensate, which is a condensate of a cyanoacetic acid ester compound and a formaldehyde compound, is depolymerized in the presence of a polymerization inhibitor under heating and reduced pressure conditions to obtain a crude 2-cyanoacrylate monomer. Depolymerization process,
A step of distilling the crude 2-cyanoacrylate monomer to obtain a purified 2-cyanoacrylate monomer,
The method for producing a 2-cyanoacrylate compound, wherein the radical polymerization inhibitor used as the polymerization inhibitor in the depolymerization step is a compound having no hydroquinone structure.
<2> The method for producing a 2-cyanoacrylate compound according to <1>, wherein the radical polymerization inhibitor contains a compound represented by the following formula (1).

In formula (1), R ₁ to R ₅ are each independently a hydrogen atom or a substituent other than a hydroxy group (excluding a phenolic hydroxy group) which may combine with each other to form a ring. Represent

<3> The 2-cyanoacrylate compound according to <1> or <2>, which includes a post-addition step of adding a polymerization inhibitor to the purified 2-cyanoacrylate monomer after the distillation purification step. Production method.
<4> The method for producing a 2-cyanoacrylate compound according to <3>, wherein the radical polymerization inhibitor added in the post-addition step of the polymerization inhibitor is a phenolic radical polymerization inhibitor.
<5> The method for producing a 2-cyanoacrylate compound according to <3> or <4>, wherein the radical polymerization inhibitor added in the post-addition step of the polymerization inhibitor is a radical polymerization inhibitor having a hydroquinone structure. .
<6> Any one of <3> to <5>, wherein the amount of the radical polymerization inhibitor added in the post-addition step of the polymerization inhibitor is 10 ppm to 1,000 ppm in the obtained 2-cyanoacrylate compound. The method for producing a 2-cyanoacrylate compound according to 1.
<7> A photocurable adhesive including a mixing step of mixing a 2-cyanoacrylate compound obtained by the production method according to any one of <1> to <6> and a Group 8 transition metal metallocene compound A method for producing a composition.

According to the present invention, there is provided a method for producing a 2-cyanoacrylate compound capable of improving the storage stability of a photocurable adhesive composition containing a Group 8 transition metal metallocene compound and a 2-cyanoacrylate compound. Can be provided.
Further, according to the present invention, it is possible to provide a method for producing a photocurable adhesive composition using the 2-cyanoacrylate compound obtained by the method for producing a 2-cyanoacrylate compound.

The description of the constituent elements described below may be made based on a typical embodiment of the present invention, but the present invention is not limited to such an embodiment. In the present specification, “to” is used to mean that the numerical values described before and after it are included as the lower limit value and the upper limit value.
In the numerical ranges described stepwise in the present specification, the upper limit value or the lower limit value described in one numerical range may be replaced with the upper limit value or the lower limit value of another stepwise described numerical range. Good. Further, in the numerical range described in the present specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples.
In the present invention, the amount of each component in the composition means the total amount of the plurality of substances present in the composition, unless a plurality of substances corresponding to each component are present in the composition, unless otherwise specified. To do.
In the present invention, the term “step” is included in this term as long as the intended purpose of the step is achieved, not only when it is an independent step but also when it cannot be clearly distinguished from other steps.
In the present invention, “mass%” and “weight%” have the same meaning, and “mass part” and “weight part” have the same meaning.
Further, in the present invention, a combination of two or more preferable aspects is a more preferable aspect.
Moreover, in this specification, "(meth) acryloyl" represents both acryloyl and methacryloyl, or either, and "(meth) acryloxy" represents both acryloxy and methacryloxy.
Further, in some of the compounds in the present specification, the hydrocarbon chain may be described by a simplified structural formula in which the symbols of carbon (C) and hydrogen (H) are omitted.
Hereinafter, the content of the present invention will be described in detail.

(Method for producing 2-cyanoacrylate compound)
The method for producing a 2-cyanoacrylate compound of the present invention (hereinafter, also simply referred to as “production method of the present invention”) comprises Depolymerization step in the presence of a polymerization inhibitor under heating and reduced pressure conditions to obtain a crude 2-cyanoacrylate monomer, and distillation of the crude 2-cyanoacrylate monomer to obtain a purified 2-cyanoacrylate monomer And a distillation purification step, and the polymerization inhibitor used in the depolymerization step is a compound having no hydroquinone structure.

In the conventional method for producing 2-cyanoacrylate, a compound having a hydroquinone structure such as hydroquinone is often used as a polymerization inhibitor during depolymerization.
However, the present inventors have found that when a compound having a hydroquinone structure is used during depolymerization, the compound having a hydroquinone structure is oxidized by the action of impurities or decomposed products, and a small amount of a compound having a benzoquinone structure is produced. I found it.
Furthermore, the present inventors have found that a compound having a benzoquinone structure greatly contributes to the storage stability of the 2-cyanoacrylate compound.
As a result of intensive studies by the present inventors, in the depolymerization step, a 2-cyanoacrylate compound obtained by using only a compound having no hydroquinone structure as a polymerization inhibitor has excellent storage stability. It has been found that a method for producing a compound can be provided.

The present invention will be described in detail below.

<2-cyanoacrylate compound>
The 2-cyanoacrylate compound (also referred to as “2-cyanoacrylate monomer”) produced by the method for producing a 2-cyanoacrylate compound of the present invention is not particularly limited as long as it is a monomer (monomer). The compound represented by the following formula (C) is preferable.

In formula (C), R is a saturated or unsaturated, straight-chain hydrocarbon group, branched chain hydrocarbon group or cyclic hydrocarbon group having 1 to 20 carbon atoms, which may have a halogen atom, or Represents an aromatic hydrocarbon group having 1 to 20 carbon atoms, which may have a halogen atom.
However, in the case where R contains an ether bond, either or both of the ether-bonded hydrocarbon residual chains may be a saturated or unsaturated C5 to C20 straight chain which may have a halogen atom. It is a chain hydrocarbon group, a branched chain hydrocarbon group or a cyclic hydrocarbon group, or an aromatic group having 5 to 20 carbon atoms which may have a halogen atom.

Specific examples of the 2-cyanoacrylate compound include 2-cyanoacrylic acid methyl, ethyl, chloroethyl, n-propyl, i-propyl, allyl, propargyl, n-butyl, i-butyl, n-pentyl and n-hexyl. , Amyl, 2-methyl-3-butenyl, 3-methyl-3-butenyl, 2-pentenyl, 6-chlorohexyl, cyclohexyl, phenyl, tetrahydrofurfuryl, 2-hexenyl, 4-methylpentenyl, 3-methyl-2 -Cyclohexenyl, norbornyl, heptyl, cyclohexanemethyl, cycloheptyl, 1-methylcyclohexyl, 2-methylcyclohexyl, 3-methyl-cyclohexyl, 2-ethylhexyl, n-octyl, 2-octyl, cyclooctyl, cyclopentanemethyl, 2 , 3-dimethyl Lohexyl, n-nonyl, isononyl, oxononyl, n-decyl, isodecyl, n-dodecyl, 2-methoxyethyl, 2-ethoxyethyl, 2-ethoxy-2-ethoxyethyl, butoxyethoxyethyl, 1- (2-methoxy- 1-methylethoxy) propyl, 2,2,2-trifluoroethyl, hexafluoroisopropyl, lauryl, isotridecyl, myristyl, cetyl, stearyl, oleyl, behenyl, hexyldecyl, octyldodecyl, benzyl, chlorophenyl, 2-pentyloxyethyl And ester compounds such as 2-hexyloxyethyl, 2-cyclohexyloxyethyl, 2- (2-ethylhexyloxy) ethyl, and 2-phenoxyethyl. Further, these are preferably used as a main component or a sub-component of the cyanoacrylate adhesive.

Among these, 2-cyanoacrylate compounds include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, cyclohexyl, phenyl, tetrahydrofurfuryl, 2-ethylhexyl of 2-cyanoacrylic acid, Preferable examples include n-octyl, 2-octyl, 2-methoxyethyl, 2-ethoxyethyl ester, and 1- (2-methoxy-1-methylethoxy) propyl.

The 2-cyanoacrylate compound obtained by the method for producing a 2-cyanoacrylate compound of the present invention does not contain a compound having a benzoquinone structure or has a content of a compound having a benzoquinone structure from the viewpoint of storage stability. It is preferably more than 0 ppm and less than 4 ppm.
Examples of the compound having a benzoquinone structure include 1,4-benzoquinone, 1,2-benzoquinone, 1,4-naphthoquinone, 9,10-anthraquinone, p-xyloquinone, 2,6-dimethyl-1,4-benzoquinone, 2, Examples include 3-dichloro-5,6-dicyanobenzoquinone, 2-hydroxy-1,4-naphthoquinone, 2-methyl-1,4-naphthoquinone, 2-chloro-1,4-naphthoquinone, and 1,4-dihydroxyanthraquinone. To be

<Depolymerization process>
In the method for producing a 2-cyanoacrylate compound of the present invention, a 2-cyanoacrylate polycondensate which is a condensate of a cyanoacetic acid ester compound and a formaldehyde compound (also referred to as “2-cyanoacrylate depolymerization precursor”), A compound in which the polymerization inhibitor used in the depolymerization step does not have a hydroquinone structure, including a depolymerization step of obtaining a crude 2-cyanoacrylate monomer by depolymerization under the presence of a polymerization inhibitor and under heating and reduced pressure conditions. Is.

In the depolymerization step, a 2-cyanoacrylate polycondensate which is a condensate of a cyanoacetic acid ester compound and a formaldehyde compound is used. In addition, the 2-cyanoacrylate polycondensate in the present disclosure is one that produces a 2-cyanoacrylate monomer (2-cyanoacrylate compound) by depolymerization.
The cyanoacetic acid ester compound is not particularly limited, and a compound corresponding to the 2-cyanoacrylate compound to be produced can be selected.
The formaldehyde compound is not particularly limited, but specific examples thereof include formaldehyde gas, formalin aqueous solution, a reaction product of formaldehyde and alcohol, paraformaldehyde and trioxane.
Moreover, these can be used individually by 1 type or in mixture of 2 or more types.
Among them, paraformaldehyde is preferable as the formaldehyde compound.

The polymerization inhibitor used in the depolymerization step is a compound having no hydroquinone structure.
From the viewpoint of storage stability, the polymerization inhibitor used in the depolymerization step preferably contains a compound having a phenolic hydroxy group, more preferably a compound represented by the following formula (1), The compound represented by the following formula (2) is particularly preferable.

In formulas (1) and (2), R ₁ to R ₅ are each independently a hydrogen atom or a hydroxy group (excluding a phenolic hydroxy group), which is bonded to each other to form a ring. Represents a substituent, R ₆ represents a hydrogen atom or an alkyl group, R ₇ to R ₁₀ each independently represents an alkyl group, a cycloalkyl group or an alkenyl group, and R ₁₁ represents a hydrogen atom, or Represents a (meth) acryloyl group.

In the formula (1), from the viewpoint of storage stability, at least one of R ₁ to R ₅ is preferably the above-mentioned substituent, and R ₁ and R ₅ are more preferably at least the above-mentioned substituents, R ₁ It is particularly preferable that ₁ , R ₃ and R ₅ are at least the above substituents.
R ₁ and R ₅ in formula (1) are each independently a linear or branched alkyl group, a cycloalkyl group, an alkyl group having a structure having a phenolic hydroxy group, or (meth) from the viewpoint of storage stability. An alkyl group having an acryloxyphenyl structure is preferable, R ₁ is a linear or branched alkyl group, and R ₅ is an alkyl group having a structure having a phenolic hydroxy group, or (meth) acryloxyphenyl It is more preferably an alkyl group having a structure, R ₁ is a linear or branched alkyl group, and R ₅ is particularly preferably an alkyl group having a (meth) acryloxyphenyl structure.
From the viewpoint of storage stability, R ₃ in the formula (1) is preferably a hydrogen atom, an alkyl group or an alkoxy group, and is a linear or branched alkyl group, a cycloalkyl group or an alkoxy group. Is more preferable, and a linear or branched alkyl group or an alkoxy group is further preferable.
The alkyl group for R ₁ , R ₃ and R ₅ is preferably an alkyl group having 1 to 8 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and more preferably 1 to 6 carbon atoms. A linear or branched alkyl group, a cycloalkyl group having 1 to 6 carbon atoms, a t-butyl group, or a 2-methyl-2-butyl group is more preferable, and a methyl group, a t-butyl group, or 2 It is particularly preferably a methyl-2-butyl group.
The alkyl group may be linear, may have a branch, may have a ring structure, and may have a substituent.
The substituent may be a group that does not lose its ability to inhibit polymerization, and examples thereof include a halogen atom, an alkoxy group, and an aryl group. Further, the substituent may be further substituted with at least one kind of group selected from the group consisting of the substituent and an alkyl group.
In formula (1), R ₂ and R ₄ are each independently preferably a hydrogen atom or an alkyl group, and more preferably a hydrogen atom.

From the viewpoint of storage stability, R ₆ in formula (2) is preferably a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and more preferably a hydrogen atom or a methyl group.
From the viewpoint of storage stability, R ₇ and R ₁₀ in the formula (2) are preferably a tertiary alkyl group, more preferably a C 4-8 tertiary alkyl group, and t- A butyl group or a 2-methyl-2-butyl group is particularly preferable.
From the viewpoint of storage stability, R ₈ and R ₉ in the formula (2) are preferably an alkyl group having 1 to 8 carbon atoms, such as a methyl group, a t-butyl group, a 2-methyl-2-butyl group, More preferably, it is a methoxy group, an ethoxy group, a propoxy group, or a butoxy group.
From the viewpoint of storage stability, R ₁₁ in formula (2) is preferably a hydrogen atom or a (meth) acryloyl group.

The 5% weight loss temperature of the polymerization inhibitor used in the depolymerization step in a nitrogen atmosphere includes a compound in the range of −150 ° C. to + 50 ° C. with respect to the boiling point of the 2-cyanoacrylate compound used. It is preferable.

Among them, from the viewpoint of storage stability, the polymerization inhibitor used in the depolymerization step is 2,2′-methylenebis (6-tert-butyl-p-cresol) (221 ° C.), 2,2′-methylenebis. (4-Ethyl-6-tert-butyl-phenol) (229 ° C), 2,2'-methylenebis (4-methyl-6-tert-butylphenol) monoacrylate (234 ° C), 2,2'-ethylenebis ( At least selected from the group consisting of 4,6-di-tert-amylphenol) monoacrylate (253 ° C.) and 2,2′-methylenebis (6- (1-methylcyclohexyl) -p-cresol) (285 ° C.) It is preferably one compound. The temperatures in parentheses are all 5% weight loss temperatures.

In the depolymerization step, the polymerization inhibitor may be used alone or in combination of two or more.
Further, the addition amount of the polymerization inhibitor used in the depolymerization step is 0 based on 100 parts by mass of the 2-cyanoacrylate polycondensate used, from the viewpoint of depolymerization yield and storage stability. It is preferably from 1 to 20 parts by mass, more preferably from 0.5 to 10 parts by mass, and particularly preferably from 1 to 5 parts by mass.

In the depolymerization step, it is preferable to carry out depolymerization in the presence of a depolymerization catalyst from the viewpoint of depolymerization rate and depolymerization yield.
As the depolymerization catalyst, diphosphorus pentoxide, phosphoric acid, polyphosphoric acid, p-toluenesulfonic acid and the like are preferably mentioned from the viewpoints of depolymerization rate and depolymerization yield. More preferred is diphosphorus.
Further, the depolymerization catalyst may have a polymerization inhibiting ability. For example, diphosphorus pentoxide, phosphoric acid, polyphosphoric acid, and p-toluenesulfonic acid are depolymerization catalysts having a polymerization inhibiting ability. It should be noted that these additives are treated as depolymerization catalysts in the present invention.

In the depolymerization step, the depolymerization catalyst may be used alone or in combination of two or more.
Further, the addition amount of the depolymerization catalyst used in the depolymerization step is 0. 0 from the viewpoint of depolymerization rate and depolymerization yield, with respect to 100 parts by mass of the 2-cyanoacrylate polycondensate used. It is preferably from 05 parts by mass to 20 parts by mass, more preferably from 0.1 parts by mass to 10 parts by mass, particularly preferably from 0.2 parts by mass to 5 parts by mass.

Further, in the depolymerization step, a high boiling point solvent such as tricresyl phosphate, dioctyl phthalate or diphenylphenylphosphonate may be added in order to reduce the viscosity in the reaction vessel during depolymerization.
In the depolymerization step, the high boiling point solvent may be used alone or in combination of two or more.
Further, the addition amount of the high boiling point solvent used in the depolymerization step is 0. 0, based on 100 parts by mass of the 2-cyanoacrylate polycondensate used, from the viewpoint of depolymerization rate and depolymerization yield. It is preferably 1 part by mass to 50 parts by mass, more preferably 1 part by mass to 30 parts by mass, and particularly preferably 2 parts by mass to 20 parts by mass.

The depolymerization temperature in the depolymerization step is not particularly limited, but is preferably 100 ° C. or higher, and more preferably 150 ° C. or higher and 320 ° C. or lower, from the viewpoint of depolymerization rate and depolymerization yield. preferable.
The pressure in the depolymerization step may be lower than 1 atm, but from the viewpoint of depolymerization rate and depolymerization yield, it is preferably 15,000 Pa or less, and 1 Pa to 10,000 Pa. More preferably, it is particularly preferably 10 Pa to 1,000 Pa.

Specifically, the depolymerization step can be suitably performed by the following method, for example.
A 2-cyanoacrylate polycondensate, which is a condensate of cyanoacetate and formaldehyde, is placed in a reactor equipped with a cooler for cooling the distillate, and the temperature is gradually raised under reduced pressure. When the temperature inside the reactor reaches the temperature at which the depolymerization reaction starts, the gas of the 2-cyanoacrylate monomer begins to be emitted, and the depolymerization is continued by keeping the temperature inside the reactor at a temperature higher than the temperature at which the reaction is started.
The cooler maintains a temperature at which the gas generated by depolymerization can be condensed. In this case, the temperature of the cooler is preferably a temperature equal to or lower than the boiling point of the 2-cyanoacrylate monomer under the pressure condition of partial condensation, for example, in the range of −30 ° C. to 50 ° C.
The crude 2-cyanoacrylate monomer is obtained by condensing with the condenser and collecting the condensed fraction.
In the depolymerization step, it is also preferable to carry out depolymerization while refluxing.
Further, in the depolymerization step, as described in Japanese Patent No. 3804396, a partial condenser and a total condenser are used as the cooler, and a high boiling point that condenses above the boiling point of the 2-cyanoacrylate monomer. The fraction may be returned to the depolymerization reaction for depolymerization.
Although the above example describes a batch type depolymerization apparatus, a continuous type depolymerization apparatus is also applicable to the present invention.

<Distillation and refining process>
The method for producing a 2-cyanoacrylate compound of the present invention includes a distillation purification step of distilling the crude 2-cyanoacrylate monomer to obtain a purified 2-cyanoacrylate monomer.
By the distillation and purification step, trace amounts of water remaining in the crude 2-cyanoacrylate monomer and polymer such as impurities can be removed, and a purified 2-cyanoacrylate monomer can be obtained.
When the crude 2-cyanoacrylate monomer contains an organic solvent, it is preferable to carry out main distillation to obtain a purified 2-cyanoacrylate monomer after distilling off the organic solvent.
The pressure during the distillation in the distillation purification step is not particularly limited and may be appropriately selected depending on the heating temperature, the boiling point of the 2-cyanoacrylate monomer, etc., but is preferably under reduced pressure, 10 Pa to 13, It is more preferably 300 Pa.
The heating temperature during the distillation in the distillation purification step is not particularly limited and may be appropriately selected depending on the pressure during the distillation, the boiling point of the 2-cyanoacrylate monomer, and the like, but is 30 ° C to 150 ° C. It is preferable that the temperature is 40 ° C. to 100 ° C.

In addition, in the distillation purification step, it is preferable to add a polymerization inhibitor to the crude 2-cyanoacrylate monomer from the viewpoint of yield and storage stability.
As the polymerization inhibitor added in the distillation and purification step, anionic polymerization inhibitors such as diphosphorus pentoxide, SO ₂ , p-toluenesulfonic acid, methanesulfonic acid, propanesultone, and BF ₃ complex are preferably mentioned. Preferred examples of the BF ₃ complex include an ether complex, an alcohol complex, a carboxylic acid complex and the like.
Among them, the polymerization inhibitor added in the distillation and purification step preferably contains diphosphorus pentoxide from the viewpoint of yield and storage stability.
Further, the radical polymerization inhibitor added as the polymerization inhibitor in the distillation purification step is a compound having no hydroquinone structure from the viewpoint of storage stability when a photocurable adhesive composition is prepared. preferable.

The polymerization inhibitor added in the distillation purification step may be used alone or in combination of two or more kinds.
The addition amount of the polymerization inhibitor in the distillation purification step is preferably 0.01 parts by mass to 5.0 parts by mass, and 0.05 parts by mass to 100 parts by mass of the crude 2-cyanoacrylate monomer. It is more preferably 1.0 part by mass.

Distillation in the distillation purification step can be performed by a known method.
It is also possible to introduce the crude 2-cyanoacrylate monomer obtained by the depolymerization step to the distillation purification step as it is, and continuously perform the distillation purification step simultaneously with the depolymerization step.

In addition, the method for producing a 2-cyanoacrylate compound of the present invention is preferably performed in an atmosphere free from or low in humidity and oxygen (eg, 0.01 vol% or less), and more preferably in an inert gas atmosphere. preferable.
Examples of the inert gas include nitrogen and argon.

<Addition step after polymerization inhibitor>
From the viewpoint of storage stability, the method for producing a 2-cyanoacrylate compound of the present invention preferably includes a post-addition step of a polymerization inhibitor that is added after the distillation purification step.
After the distillation and purification step, even if a compound having a hydroquinone structure is added as a polymerization inhibitor, the production of a compound having a benzoquinone structure is suppressed and the storage stability is excellent.
The polymerization inhibitor added in the post-addition step of the polymerization inhibitor is preferably a phenolic radical polymerization inhibitor from the viewpoint of storage stability. Examples of the phenol-based radical polymerization inhibitor include hydroquinone, mequinol, butylhydroxyanisole, di-tert-butylhydroxytoluene, methylhydroquinone, methoxyhydroquinone, 2,6-dimethylhydroquinone, 2,6-di-tert-butylhydroquinone, At least one selected from the group consisting of 4-tert-butylcatechol, tert-butylhydroquinone, 6-tert-butyl-4-xylenol, 2,6-di-tert-butylphenol and 1,2,4-trihydroxybenzene It is preferably a seed and is a radical polymerization inhibitor having a hydroquinone structure, such as hydroquinone, methylhydroquinone, methoxyhydroquinone, 2,6-dimethylhydroquinone and 2,6-di-ter. - and particularly preferably at least one selected from the group consisting of butyl hydroquinone.

Further, as the polymerization inhibitor in the post-addition step of the polymerization inhibitor, the polymerization inhibitor described in the depolymerization step and the distillation / purification step described above is also preferably exemplified.
Among these, anionic polymerization inhibitors such as diphosphorus pentoxide, SO ₂ , p-toluenesulfonic acid, methanesulfonic acid, propanesultone, and BF ₃ complex are preferable as these polymerization inhibitors.
From the viewpoint of storage stability, it is also preferable to use a radical polymerization inhibitor having a hydroquinone structure and an anionic polymerization inhibitor together as the polymerization inhibitor.

The polymerization inhibitor in the post-addition step of the polymerization inhibitor may be used alone or in combination of two or more kinds.
The amount of the polymerization inhibitor added in the post-addition step of the polymerization inhibitor is preferably 50 ppm to 1% by mass, and more preferably 20 ppm to 5,000 ppm in the resulting 2-cyanoacrylate compound.
The amount of the radical polymerization inhibitor added in the post-addition step of the polymerization inhibitor may be 50 ppm to 1% by mass in the obtained 2-cyanoacrylate compound, when it is used for other than the photocurable adhesive composition. When used in addition to the photocurable adhesive composition, it is preferably 20 ppm to 5,000 ppm within a range not exceeding the addition amount of the photoradical generator.
The amount of the anionic polymerization inhibitor added in the post-addition step of the polymerization inhibitor is preferably 2 ppm to 200 ppm, more preferably 5 ppm to 100 ppm in the obtained 2-cyanoacrylate compound.

The method of adding the polymerization inhibitor in the post-addition step of the polymerization inhibitor is not particularly limited, and the polymerization initiator may be added to the purified 2-cyanoacrylate monomer. For example, in the distillation purification step, Examples include a method in which the purified 2-cyanoacrylate monomer is added in advance to a container for collection, or a method after the distillation is completed.
Further, as described above, the purified 2-cyanoacrylate monomer obtained by the distillation purification step is directly introduced to the polymerization inhibitor post-addition step, and the polymerization inhibitor post-addition step is continuously performed simultaneously with the distillation purification step. It is also possible to do so.

<Polycondensation process>
In the method for producing a 2-cyanoacrylate compound of the present invention, before the depolymerization step, a cyanoacetic acid ester compound and a formaldehyde compound are condensed in an organic solvent in the presence of a basic catalyst to give a 2-cyanoacrylate compound. A polycondensation step of obtaining a condensate (2-cyanoacrylate depolymerization precursor) may be included.
The cyanoacetic acid ester compound and the formaldehyde compound in the polycondensation step are the same as the cyanoacetic acid ester compound and the formaldehyde compound described in the depolymerization step, respectively, and the preferred embodiments are also the same.

As the basic catalyst used in the polycondensation step, known ones can be used.
Specifically, for example, organic basic substances such as piperidine, morpholine, quinoline, isoquinoline, ethylamine, diethylamine, triethylamine, ethanolamine, pyridine acetate, and inorganic basic substances such as sodium hydroxide, potassium hydroxide, and ammonia can be used. Can be mentioned.

The basic catalysts may be used alone or in combination of two or more.
The addition amount of the basic catalyst in the polycondensation step is not particularly limited, but from the viewpoint of reactivity and yield, 0.0001 parts by mass to 0.01 parts by mass relative to 100 parts by mass of the cyanoacetic acid ester compound. Is preferred.

A solvent is preferably used in the polycondensation step.
Examples of the solvent used in the polycondensation step include toluene, xylene, benzene, trichloroethylene, cyclohexane, ethyl acetate, methanol, ethanol, isopropanol, tricresyl phosphate, dioctyl phthalate and diphenylphenylphosphonate.
The said solvent may be used individually by 1 type, or may use 2 or more types together.
The amount of the solvent used is not particularly limited and may be appropriately selected as desired.

The 2-cyanoacrylate polycondensate obtained by the polycondensation step is subjected to a known appropriate pretreatment so that the 2-cyanoacrylate polycondensate is decomposed into the 2-cyanoacrylate monomer in the subsequent depolymerization step. May be.
As the pretreatment, for example, water contained in the raw material or water generated in the condensation step is removed by azeotropy when a solvent that forms an azeotropic mixture with water is used, and if not, A treatment of distilling off is preferable. Further, the basic catalyst used is preferably deactivated with an acidic substance, washed with water, or removed with a solvent.

The method for producing a 2-cyanoacrylate compound of the present invention may include other known steps in addition to the steps described above.

(Photocurable adhesive composition and method for producing the same)
The photocurable adhesive composition of the present invention is a composition containing a 2-cyanoacrylate compound obtained by the production method of the present invention, and contains the 2-cyanoacrylate compound obtained by the production method of the present invention and a Group 8 compound. A composition containing a transition metal metallocene compound is preferable.
Further, the method for producing the photocurable adhesive composition of the present invention preferably includes a mixing step of mixing the 2-cyanoacrylate compound obtained by the production method of the present invention and a Group 8 transition metal metallocene compound. .

The method for producing the photocurable resin composition of the present invention is not particularly limited and may be produced by mixing the components described above and below, but there is little or no moisture and oxygen (for example, 0.01% by volume or less). ) Mixing under an atmosphere is preferable, and mixing under an inert gas atmosphere is more preferable.
Examples of the inert gas include nitrogen and argon.
Further, the method for producing the photocurable resin composition of the present invention is preferably carried out under light shielding.
The mixing method is not particularly limited, and a known mixing method can be used.

From the viewpoint of storage stability, the photocurable adhesive composition of the present invention does not contain a compound having a benzoquinone structure, or the content of the compound having a benzoquinone structure is more than 0 ppm and less than 4 ppm. It is preferable that the compound having a benzoquinone structure is not contained, or the content of the compound having a benzoquinone structure is more than 0 ppm and 3 ppm or less, and the compound having a benzoquinone structure is not contained, or the benzoquinone structure is not contained. The content of the compound contained is more preferably more than 0 ppm and 1.5 ppm or less.
In addition, when the photocurable adhesive composition of this invention contains the compound which has 2 or more types of benzoquinone structures, the said content is the total content of the compound which has 2 or more types of benzoquinone structures.

<Group 8 transition metal metallocene compound>
The photocurable adhesive composition of the present invention preferably contains a Group 8 transition metal metallocene compound.
It is estimated that the Group 8 transition metal metallocene compound functions as a photopolymerization initiator. Further, since the light absorption wavelength of the Group 8 transition metal metallocene compound is also on the long wavelength side of 500 nm or more, the photocurable adhesive composition of the present invention has a wider wavelength range, that is, an ultraviolet range and a visible range. Light curing is possible even with light in the light range.

Examples of the Group 8 transition metal metallocene compound include a ferrocene compound in which the transition metal is iron, an osmocene compound in which osmium is a ruthenocene compound in which ruthenium is a cobaltocene compound in which cobalt is a nickelocene compound. Mention may be made of metallocene compounds having a Group 8 transition metal element in the table.
Among these, at least one compound selected from the group consisting of ferrocene compounds and ruthenocene compounds is preferable from the viewpoint of photocurability and storage stability.

Specific examples of the Group 8 transition metal metallocene compound include, for example, ferrocene, ethylferrocene, n-butylferrocene, benzoylferrocene, acetylferrocene, t-amylferrocene, 1,1′-dimethylferrocene, 1,1 ′. -Di-n-butylferrocene, 1,1'-dibenzoylferrocene, 1,1'-di (acetylcyclopentadienyl) iron, bis (pentamethylcyclopentadienyl) iron, bis (cyclopentadienyl) Examples thereof include osmium, bis (pentamethylcyclopentadienyl) osmium, ruthenocene (bis (cyclopentadienyl) ruthenium), and bis (pentamethylcyclopentadienyl) ruthenium.
Further, as the Group 8 transition metal metallocene compound, a transition metal metallocene compound of Group 8 of the periodic table having an aromatic electron type ligand described in JP-A-2003-277422 can be preferably used.
Among these, the Group 8 transition metal metallocene compound is at least one selected from the group consisting of ferrocene, ethylferrocene, n-butylferrocene, benzoylferrocene, and ruthenocene, from the viewpoint of photocurability and storage stability. Are preferred, and at least one compound selected from the group consisting of ferrocene and ruthenocene is particularly preferred.

The photocurable adhesive composition of the present invention may contain one kind of Group 8 transition metal metallocene compound alone, or may contain two or more kinds thereof.
The content of the Group 8 transition metal metallocene compound in the photocurable adhesive composition of the present invention is preferably 1 ppm to 50,000 ppm, and preferably 10 ppm to 10 ppm, from the viewpoint of photocurability and storage stability. It is more preferably 2,000 ppm, particularly preferably 20 ppm to 2,000 ppm.

<2-cyanoacrylate compound>
The photocurable adhesive composition of the present invention contains the 2-cyanoacrylate compound obtained by the production method of the present invention.
The photocurable adhesive composition of the present invention may include one type of the 2-cyanoacrylate compound alone or may include two or more types.
The content of the 2-cyanoacrylate compound in the photocurable adhesive composition of the present invention is preferably 40% by mass or more, and more preferably 60% by mass or more, from the viewpoint of curability, adhesion speed, and adhesive strength. More preferably.

<Photo radical generator>
From the viewpoint of photocurability, the photocurable adhesive composition of the present invention preferably further contains a photoradical generator.
As the photo-radical generator, a known photo-radical generator used when photopolymerizing a radical-polymerizable compound can be used.
Examples of the photoradical generator include an acylgermane-based compound, an acylphosphine oxide-based compound, a hydroxy group, an acetophenone-based compound that does not have a nitrogen atom and a thioether bond, and a benzoin-based compound that does not have a hydroxy group, a nitrogen atom, and a thioether bond. To be
Among them, as the photoradical generator, an acylgermane compound is preferable from the viewpoint of photocurability, adhesion speed, and storage stability.

The acylgermane compound is preferably a monoacylgermane compound or a bisacylgermane compound, more preferably a bisacylgermane compound.
Preferable examples of the acylgermane compound include Ivocerin (manufactured by Ivoclar Vivadent).

As the acylphosphine oxide-based compound, monoacylphosphine oxide-based compounds and bisacylphosphine oxide-based compounds are preferable, and bisacylphosphine oxide-based compounds are more preferable.
Preferred examples of the monoacylphosphine oxide compound include compounds represented by the following formula (A-1).

In formula (A-1), R ^A1 and R ^A2 are each independently an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a phenyl group, or 1 to 3 carbon atoms having 1 to 3 carbon atoms. Represents an phenyl group substituted with an alkyl group having 8 or an alkoxy group having 1 to 8 carbon atoms, and R ^A3 is a linear or branched alkyl group having 1 to 18 carbon atoms, which is unsubstituted or substituted with an acetyloxy group. Or a cycloalkyl group having 3 to 12 carbon atoms; an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an aryl group which is unsubstituted or substituted by a halogen atom; or by the following formula (A-2) Represents a group represented.

In formula (A-2), R ^A4 and R ^A5 each independently represent an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a phenyl group, or 1 to 3 carbon atoms having 1 to 3 carbon atoms. 8 represents a phenyl group substituted by an alkyl group having 8 or an alkoxy group having 1 to 8 carbon atoms, and X ^A1 represents a p-phenylene group.

Examples of the acylphosphine oxide compounds include methylisobutyroylmethylphosphinate, methylisobutyroylphenylphosphinate, methylpivaloylphosphinate, methyl-2-ethylhexanoylphosphinate, and isopropyl-2-ethylhexanoylphenylphosphonate. , Methyl-p-tolylphenylphosphinate, methyl-o-tolyl-phenylphosphinate, methyl-2,4-dimethylbenzoylphenylphosphinate, methylacryloylphenylphosphonate, isobutyroyldiphenylphosphine oxide, 2-methylhexanoyl Diphenylphosphine oxide, o-toluyldiphenylphosphine oxide, pt-butylbenzoyldiphenylphosphine oxide, 3-polydylcarbonyldi E cycloalkenyl phosphine oxide, acryloyl-diphenyl phosphine oxide, benzoyl diphenylphosphine oxide, and the like Ajiboirubisu (diphenylphosphine oxide).

Preferred examples of the bisphosphine oxide-based compound include compounds represented by the following formula (A-3).

R ^p in the formula (A-3) is unsubstituted, is an alkyl group having 1 to 12 carbon atoms, an alkylthio group having 1 to 8 carbon atoms, or a halogen atom, and each R ^p is the same. It may be different.

The alkyl group having 1 to 12 carbon atoms in R ^p in formula (A-3) may be linear or branched, and is, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl. , Tert-butyl, pentyl, isopentyl, hexyl, heptyl, octyl, nonyl, decyl or dodecyl groups. It is preferably an alkyl group having 1 to 6 carbon atoms, more preferably 1 to 4 carbon atoms.
The alkylthio group having 1 to 8 carbon atoms in R ^p in formula (A-3) may be linear or branched, and examples thereof include methylthio, ethylthio, propylthio, isopropylthio, butylthio, tert-butylthio, Hexylthio or octylthio are mentioned. Of these, methylthio is preferable.
Examples of the halogen atom include chlorine atom, bromine atom, and iodine atom. Of these, chlorine atom is preferable.

Examples of the bisacylphosphine oxide compound include bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide and bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide.

Examples of the acetophenone compound include 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, 4-t-butyltrichloroacetophenone and diethoxyacetophenone.
Examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and benzyl methyl ketal.

Among these, the photoradical generators are dibenzoyldiethylgermanium, bis (4-methoxybenzoyl) dimethylgermanium, and bis (4-methoxybenzoyl) diethylgermanium from the viewpoints of photocurability, adhesion rate, and storage stability. , At least one compound selected from the group consisting of ferrocenylacylgermanium, benzoyldimethylgermanium, bis (4-methylbenzoyl) diethylgermanium, bis (4-methylbenzoyl) dimethylgermanium and dibenzoyldibutylgermanium. Are preferred, and dibenzoyldiethylgermanium, bis (4-methoxybenzoyl) dimethylgermanium, bis (4-methoxybenzoyl) diethylgermanium, bis (4-methylbenzoyl) diethylgermane Maniumu, more preferably bis (4-methylbenzoyl) at least one compound selected from the group consisting of dimethyl germanium and dibenzo dichloride butyl germanium.

The photocurable adhesive composition of the present invention may contain one type of photoradical generator alone, or may contain two or more types.
The content of the photoradical generator in the photocurable adhesive composition of the present invention is 0 with respect to the total mass of the photocurable adhesive composition from the viewpoint of photocurability, adhesion speed, and storage stability. The amount is preferably 0.01% by mass to 5% by mass, more preferably 0.05% by mass to 2% by mass, and particularly preferably 0.05% by mass to 1% by mass.

<Polymerization inhibitor>
The photocurable adhesive composition of the present invention preferably further contains a polymerization inhibitor from the viewpoint of storage stability.
As the polymerization inhibitor, a known polymerization inhibitor can be used.

Preferred examples of the polymerization inhibitor include diphosphorus pentoxide, SO ₂ , p-toluene sulfonic acid, methane sulfonic acid, propane sultone, BF ₃ complex and other anionic polymerization inhibitors having no hydroquinone structure.

Further, as the above-mentioned polymerization inhibitor, the above-mentioned polymerization inhibitor having no hydroquinone structure such as the compound represented by the formula (1) or the formula (2) is preferably exemplified.
As a polymerization inhibitor having no hydroquinone structure, from the viewpoint of storage stability, mequinol, butylhydroxyanisole, dibutylhydroxytoluene, di-tert-butylhydroxytoluene, 6-tert-butyl-4-xylenol, 2,6- Di-tert-butylphenol, 2,2'-methylenebis (6-tert-butyl-p-cresol), 2,2'-methylenebis (4-ethyl-6-tert-butyl-phenol), 2,2'-methylenebis (4-Methyl-6-tert-butylphenol) monoacrylate, 2,2'-ethylenebis (4,6-di-tert-amylphenol) monoacrylate and 2,2'-methylenebis (6- (1-methylcyclohexyl) ) -P-Cresol) It is preferable that the species.

From the viewpoint of storage stability, the polymerization inhibitor preferably contains a radical polymerization inhibitor having a hydroquinone structure, more preferably a radical polymerization inhibitor having a 1,4-hydroquinone structure.
The radical polymerization inhibitor having a hydroquinone structure is 1,4-hydroquinone, 1,2-hydroquinone, methylhydroquinone, 2,6-dimethylhydroquinone, 2,6-di-tert-butylhydroquinone from the viewpoint of storage stability. At least one compound selected from the group consisting of 1,4-dihydroxynaphthalene, 1,2-dihydroxynaphthalene, and 9,10-dihydroxyanthracene is preferable, and 1,4-hydroquinone, 1,2-hydroquinone, More preferably, it is at least one selected from the group consisting of methylhydroquinone, methoxyhydroquinone, 2,6-dimethylhydroquinone and 2,6-di-tert-butylhydroquinone, and hydroquinone, methylhydroquinone and methoxyha are preferred. It is particularly preferred from the group consisting of Dorokinon is at least one selected.

The radical polymerization inhibitor having a hydroquinone structure is preferably added after the distillation and purification at the time of preparing the photocurable adhesive composition or at the time of producing the 2-cyanoacrylate compound as a raw material. It is more preferable to prepare the curable adhesive composition.

The photocurable adhesive composition of the present invention may contain one type of polymerization inhibitor or two or more types of polymerization inhibitors. Among them, from the viewpoint of storage stability, it is preferable to contain an anionic polymerization inhibitor having no hydroquinone structure, and it is more preferable to contain a radical polymerization inhibitor having no hydroquinone structure and an anionic polymerization inhibitor having no hydroquinone structure. It is particularly preferable to contain a radical polymerization inhibitor having a hydroquinone structure, a radical polymerization inhibitor having no hydroquinone structure, and an anionic polymerization inhibitor having no hydroquinone structure.
The content of the polymerization inhibitor is preferably 50 ppm to 1% by mass, and more preferably 20 ppm to 5,000 ppm, based on the total mass of the photocurable adhesive composition.
Further, the content of the radical polymerization inhibitor having a hydroquinone structure is preferably 10 ppm or more and 1000 ppm or less, and more preferably 20 ppm or more and 500 ppm or less.

<Other additives>
The photocurable adhesive composition of the present invention may contain an additive other than the above-mentioned components.
Other additives are not particularly limited, and known additives can be used.
As other additives, for example, anionic polymerization accelerators, plasticizers, thickeners, fumed silica, particles, fillers, colorants, fragrances, solvents, strength improvers, etc., depending on the purpose, etc. An appropriate amount of the adhesive composition can be blended within a range that does not impair the curability and the adhesive strength of the adhesive composition.
The content of other additives is not particularly limited, but is preferably 20% by mass or less, and more preferably 10% by mass or less, based on the total mass of the photocurable adhesive composition.

Examples of anionic polymerization accelerators include polyalkylene oxides, crown ethers, silacrown ethers, calixarenes, cyclodextrins, and pyrogallol cyclic compounds. The polyalkylene oxides are polyalkylene oxides and derivatives thereof, and include, for example, JP-B-60-37836, JP-B-1-43790, JP-A-63-128088, and JP-A-3-167279. Examples thereof include those disclosed in the gazette, US Pat. No. 4,386,193, US Pat. No. 4,424,327 and the like. Specifically, (1) polyalkylene oxide such as diethylene glycol, triethylene glycol, polyethylene glycol and polypropylene glycol, (2) polyethylene glycol monoalkyl ester, polyethylene glycol dialkyl ester, polypropylene glycol dialkyl ester, diethylene glycol monoalkyl ether, diethylene glycol Examples include polyalkylene oxide derivatives such as dialkyl ether, dipropylene glycol monoalkyl ether, and dipropylene glycol dialkyl ether. Examples of the crown ethers include those disclosed in Japanese Examined Patent Publication No. 55-2236 and Japanese Patent Laid-Open No. 3-167279. Specifically, 12-crown-4, 15-crown-5, 18-crown-6, benzo-12-crown-4, benzo-15-crown-5, benzo-18-crown-6, dibenzo-18. -Crown-6, dibenzo-24-crown-8, dibenzo-30-crown-10, tribenzo-18-crown-6, asym-dibenzo-22-crown-6, dibenzo-14-crown-4, dicyclohexyl-24 -Crown-8, cyclohexyl-12-crown-4,1,2-decalyl-15-crown-5,1,2-naphtho-15-crown-5,3,4,5-naphthyl-16-crown-5 1,2-methylbenzo-18-crown-6,1,2-tert-butyl-18-crown-6,1,2-vinylbenzo-15-crown- Etc. The. Examples of silacrown ethers include those disclosed in JP-A-60-168775. Specific examples thereof include dimethylsila-11-crown-4, dimethylsila-14-crown-5, dimethylsila-17-crown-6 and the like. Examples of the calixarene include those disclosed in JP-A-60-179482, JP-A-62-235379, JP-A-63-88152 and the like. Specifically, 5,11,17,23,29,35-hexa-tert-butyl-37,38,39,40,41,42-hexahydrooxycalix [6] arene, 37,38,39, 40,41,42-hexahydrooxycalix [6] arene, 37,38,39,40,41,42-hexa- (2-oxo-2-ethoxy) -ethoxycalix [6] arene, 25,26, 27,28-tetra- (2-oxo-2-ethoxy) -ethoxycalix [4] arene, tetrakis (4-t-butyl-2-methylenephenoxy) ethyl acetate and the like can be mentioned. Examples of cyclodextrins include those disclosed in JP-A-5-505835. Specific examples include α-, β-, or γ-cyclodextrin. Examples of the pyrogallol cyclic compounds include compounds disclosed in JP 2000-191600 A and the like. Specifically, 3,4,5,10,11,12,17,18,19,24,25,26-dodecaethoxycarbomethoxy-C-1, C-8, C-15, C-22- Tetramethyl [14] -metacyclophane and the like can be mentioned. These anionic polymerization accelerators may be used alone or in combination of two or more.

The plasticizer can be contained within a range that does not impair the effects of the present invention.
Examples of the plasticizer include triethyl acetyl citrate, tributyl acetyl citrate, dimethyl adipate, diethyl adipate, dimethyl sebacate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisodecyl phthalate, dihexyl phthalate, and phthalic acid. Diheptyl, dioctyl phthalate, bis (2-ethylhexyl) phthalate, diisononyl phthalate, diisotridecyl phthalate, dipentadecyl phthalate, dioctyl terephthalate, diisononyl isophthalate, decyl toluate, bis (2-ethylhexyl) camphorate, 2- Ethylhexyl cyclohexylcarboxylate, diisobutyl fumarate, diisobutyl maleate, triglyceride caproate, 2-ethylhexyl benzoate, dipropylene glycol dibe Zoeto, and the like. Among these, tributyl acetyl citrate, dimethyl adipate, dimethyl phthalate, 2-ethylhexyl benzoate, and dipropylene glycol are well compatible with 2-cyanoacrylic acid ester and have high plasticization efficiency. Dibenzoate is preferred. These plasticizers may be used alone or in combination of two or more. The content of the plasticizer is not particularly limited, but when the content of the 2-cyanoacrylate compound is 100 parts by mass, preferably 3 parts by mass to 50 parts by mass, more preferably 10 parts by mass to 45 parts by mass. And more preferably 20 to 40 parts by mass. When the content of the plasticizer is 3 parts by mass to 50 parts by mass, it is possible to improve the retention rate of the adhesive strength after the cold and heat cycle test.

Further, as the thickener, polymethylmethacrylate, a copolymer of methylmethacrylate and an acrylate ester, a copolymer of methylmethacrylate and another methacrylate ester, acrylic rubber, polyvinyl chloride, polystyrene, Examples thereof include cellulose ester, polyalkyl-2-cyanoacrylic acid ester and ethylene-vinyl acetate copolymer. These thickeners may be used alone or in combination of two or more.

The photocurable adhesive composition of the present invention may contain fumed silica.
This fumed silica is an ultrafine powder (preferably having a primary particle size of 500 nm or less, particularly preferably 1 nm to 200 nm) anhydrous silica. For example, this anhydrous silica is made from silicon tetrachloride as a raw material and is heated in a flame at high temperature. An ultrafine powder (preferably having a primary particle size of 500 nm or less, particularly preferably 1 nm to 200 nm) anhydrous silica produced due to oxidation in a gas phase, which is hydrophilic silica having high hydrophilicity and hydrophobic silica With highly hydrophobic silica. Although any of these fumed silicas can be used, hydrophobic silicas are preferable because they have good dispersibility in a 2-cyanoacrylate compound.

As the hydrophilic silica, various commercially available products can be used, and examples thereof include Aerosil 50, 130, 200, 300 and 380 (these are trade names and manufactured by Nippon Aerosil Co., Ltd.). The specific surface areas of these hydrophilic silicas are 50 ± 15 m ² / g, 130 ± 25 m ² / g, 200 ± 25 m ² / g, 300 ± 30 m ² / g, 380 ± 30 m ² / g, respectively. Further, as the commercially available hydrophilic silica, Reorosil QS-10, QS-20, QS-30 and QS-40 (these are trade names, manufactured by Tokuyama Corporation) and the like can be used. The specific surface areas of these hydrophilic silicas are 140 ± 20 m ² / g, 220 ± 20 m ² / g, 300 ± 30 m ² / g, and 380 ± 30 m ² / g, respectively. In addition to these, commercially available hydrophilic silica manufactured by CABOT or the like can also be used.

Further, as the hydrophobic silica, a compound capable of reacting with a hydroxy group existing on the surface of the hydrophilic silica to form a hydrophobic group, or adsorbed on the surface of the hydrophilic silica to form a hydrophobic layer on the surface It is possible to use a product produced by treating the surface of the hydrophilic silica by bringing the compound into contact with the hydrophilic silica in the presence or absence of a solvent, preferably by heating.

Examples of the compound used for surface-treating hydrophilic silica to make it hydrophobic include alkyl-, aryl-, and aralkyl-based silane coupling agents having a hydrophobic group such as n-octyltrialkoxysilane, methyltrichlorosilane, and dimethyldisilane. Examples thereof include silylating agents such as chlorosilane and hexamethyldisilazane, silicone oils such as polydimethylsiloxane, higher alcohols such as stearyl alcohol, and higher fatty acids such as stearic acid. As the hydrophobic silica, a product hydrophobized with any compound may be used.

Examples of commercially available hydrophobic silica include Aerosil RY200 and R202, which are surface-treated with silicone oil and hydrophobized, and Aerosil R974, R972, R976, and n-octyltril, which are hydrophobized and surface-treated with a dimethylsilylating agent. Aerosil R805 surface-treated with methoxysilane and hydrophobized, Aerosil R811, R812 surface-treated with trimethylsilylating agent and hydrophobized (these are trade names, manufactured by Nippon Aerosil Co., Ltd.) and methyltri Examples include hydrophobically treated Reolosil MT-10 (trade name, manufactured by Tokuyama Corporation) and the like, which is surface-treated with chlorosilane. The specific surface areas of these hydrophobic silicas are 100 ± 20 m ² / g, 100 ± 20 m ² / g, 170 ± 20 m ² / g, 110 ± 20 m ² / g, 250 ± 25 m ² / g, 150 ± 20 m ^{2, respectively.} / G, 150 ± 20 m ² / g, 260 ± 20 m ² / g, 120 ± 10 m ² / g.

The preferable content of fumed silica in the photocurable adhesive composition of the present invention is 1 part by mass to 30 parts by mass when the content of the 2-cyanoacrylate compound is 100 parts by mass. The preferred content of the fumed silica depends on the type of the 2-cyanoacrylate compound, the type of the fumed silica, and the like, but 1 part by mass to 25 parts by mass, and particularly preferred content is 2 parts by mass to 20 parts by mass. It is a department. When the content of fumed silica is 1 part by mass to 30 parts by mass, it is possible to obtain an adhesive composition having good workability without impairing the curability and adhesive strength of the photocurable adhesive composition. it can.

The method for curing the photocurable adhesive composition of the present invention is not particularly limited as long as it can be polymerized and cured by a 2-cyanoacrylate compound, and it can be cured by light or moisture such as moisture. Good.
When the photocurable adhesive composition of the present invention is cured by light, it is necessary to irradiate ultraviolet rays or visible light using a high pressure mercury lamp, a halogen lamp, a xenon lamp, an LED (light emitting diode) lamp, sunlight or the like. Can be cured.

The method for storing the photocurable adhesive composition of the present invention may be carried out by a known storage method, for example, mixing in an atmosphere without or low in humidity and oxygen (for example, 0.01% by volume or less). It is preferable to mix, and it is more preferable to mix under an inert gas atmosphere.
Examples of the inert gas include nitrogen and argon.
Further, the photocurable adhesive composition of the present invention is preferably stored under light shielding.

The photocurable adhesive composition of the present invention can be used as a known 2-cyanoacrylate composition and as a photocurable adhesive composition.
For example, it can be used as a so-called instant adhesive, and can also be used as a photocurable instant adhesive.
The photocurable adhesive composition of the present invention has photocurability and moisture curability, and since it has excellent storage stability, it can be used in a wide range of fields such as general use, industrial use, and medical use. .
Specifically, for example, sealing of electronic components, attachment of reel seats and threading guides on fishing rods, fixing of wire materials such as coils, fixing of magnetic heads to pedestals, and filling used for tooth treatment It can be suitably used for adhesion or fixing between the same or different kinds of articles such as adhesive or artificial nail adhesion or decoration, or coating.

The present invention will be specifically described below based on examples. The present invention is not limited to these examples. Further, in the following, “part” and “%” mean “part by mass” and “mass%”, respectively, unless otherwise specified.

(Example 1)
<Production of 2-octyl ester of 2-cyanoacrylic acid (2-OctCA)>
A depolymerization reactor equipped with a cooler and a stirrer was charged with 100 parts by mass of a condensate of 2-octyl cyanoacetate and paraformaldehyde, and p-toluenesulfonic acid (PTS) was added in an amount of 0. 9 parts by mass, and 2.1 parts by mass of Sumilizer GS (GS, the following compound, manufactured by Sumitomo Chemical Co., Ltd.) were added to 100 parts by mass of the condensate.

Depolymerization was carried out under a reduced pressure of 1,000 Pa or less in the depolymerization reactor while keeping the internal temperature at 150 ° C to 200 ° C. The fraction was condensed by a cooler, and crude 2-OctCA was collected in a collection receiver. Depolymerization was terminated when the crude 2-OctCA was no longer distilled.

To the obtained crude 2-OctCA, 0.13 parts by mass of PTS and 0.5 parts by mass of GS were added per 100 parts by mass of crude 2-OctCA, and the mixture was distilled to remove impurities having a low boiling point as an initial distillation, followed by purification. 2-OctCA was obtained.
20 ppm of BF ₃ / methanol complex was added to the obtained purified 2-OctCA, and Sumilizer MDP-S (MDP-S, the following compound, manufactured by Sumitomo Chemical Co., Ltd.) (the following compound) was added to 1 of the whole. It was added so that the concentration would be 1,000 ppm.
The total yield from the condensate was 40%.
The acid content (acid content (μg equivalent)) per 1 g of the obtained purified 2-OctCA was 0.63 μg.
The acid content was measured by the neutralization titration method.

<Production of photocurable adhesive composition>
Ferrocene (photopolymerization initiator, manufactured by Wako Pure Chemical Industries, Ltd.) was added to the purified 2-OctCA containing BF ₃ · methanol complex and Sumilizer MDP-S at 600 ppm in the composition, and Ivocerin (photopolymerization start). Agent, the following compound, manufactured by Ivoclar Vivadent) were mixed so as to be 3,000 ppm to obtain a photocurable adhesive composition of Example 1.

(Example 2)
<Production of 2-Ethoxyethyl Ester of 2-Cyanoacrylic Acid (EtOEtCA)>
A depolymerization reactor equipped with a condenser and a stirrer was charged with 100 parts by mass of a condensate of 2-ethoxyethyl cyanoacetate and paraformaldehyde, and diphosphorus pentoxide (P ₂ O ₅ ) was added to 100 parts by mass of the condensate. 1.1 parts by mass and 3.5 parts by mass of GS were added to 100 parts by mass of the condensate.

Depolymerization was carried out under a reduced pressure of 1,000 Pa or less in the depolymerization reactor while keeping the internal temperature at 150 ° C to 200 ° C. The fraction was condensed by a cooler, and crude EtOEtCA was recovered in a recovery receiver. The depolymerization was terminated when the crude EtOEtCA was no longer distilled.

To 100 parts by mass of the crude EtOEtCA, 1.5 parts by mass of diphosphorus pentoxide, 0.5 parts by mass of PTS and 3.0 parts by mass of MDP-S were added to the obtained crude EtOEtCA for distillation, and impurities having a low boiling point were initially distilled. As a result, purified EtOEtCA was obtained.
To the obtained purified EtOEtCA, BF ₃ / methanol complex was added at 20 ppm to the whole, and MDP-S (the following compound) was added at 1000 ppm to the whole.
The total yield from the condensate was 35%.
The acid content (acid content (μg equivalent)) per 1 g of the obtained purified EtOEtCA was 0.12 μg.

<Production of photocurable adhesive composition>
BF ₃ · methanol complex and Sumilizer MDP-S in place of the purified 2-OctCA added with, except for using purified EtOEtCA with added BF ₃ · methanol complex and Sumilizer MDP-S is in the same manner as described in Example 1 A photocurable adhesive composition of Example 2 was produced.

(Example 3)
<Production of isobutyl ester of 2-cyanoacrylic acid (iBuCA)>
A depolymerization reactor equipped with a condenser and a stirrer was charged with 100 parts by mass of a condensate of isobutyl cyanoacetate and paraformaldehyde, and phosphorous pentoxide (P ₂ O ₅ ) was added to 100 parts by mass of the condensate in an amount of 0. 5 parts by mass and 1.0 part by mass of MDP-S were added to 100 parts by mass of the condensate.

Depolymerization was carried out under a reduced pressure of 1,000 Pa or less in the depolymerization reactor while keeping the internal temperature at 150 ° C to 200 ° C. The fraction was condensed by a cooler, and the crude iBuCA was recovered in a recovery receiver. Depolymerization was terminated when the crude iBuCA was no longer distilled.

After adding 0.5 parts by mass of diphosphorus pentoxide and 1.0 part by mass of MDP-S to 100 parts by mass of the crude iBuCA, and distilling the obtained crude iBuCA, the low boiling point impurities were distilled off as an initial distillation. , Purified iBuCA were obtained.
To the obtained purified iBuCA, BF ₃ / methanol complex was added in an amount of 20 ppm to the whole, and MDP-S (the following compound) was added to the entire amount of 1,000 ppm.
The total yield from the condensate was 40%.
The acid content (acid content (μg equivalent)) per 1 g of the obtained purified iBuCA was 0.19 μg.

<Production of photocurable adhesive composition>
BF ₃ · methanol complex and Sumilizer MDP-S in place of the purified 2-OctCA added with, except for using purified iBuCA with added BF ₃ · methanol complex and Sumilizer MDP-S is in the same manner as described in Example 1 A photocurable adhesive composition of Example 3 was produced.

Table 1 summarizes the details of the method for producing the 2-cyanoacrylate compound in Examples 1 to 3.

(Example 4)
The same procedure as in Example 1 was repeated except that hydroquinone was added to the purified 2-OctCA containing BF ₃ · methanol complex and Sumilizer MDP-S so that the content of hydroquinone was 40 ppm. Purified 2-OctCA and the photocurable adhesive composition of Example 4 were obtained.

(Example 5)
Purified EtOEtCA of Example 5 was prepared in the same manner as in Example 2 except that hydroquinone was added to the purified EtOEtCA to which BF ₃ / methanol complex and Sumilizer MDP-S were added so that the content of hydroquinone was 40 ppm. , And the photocurable adhesive composition of Example 5 were obtained.

(Example 6)
Purified EtOEtCA of Example 6 was prepared in the same manner as in Example 2 except that hydroquinone was added to purified EtOEtCA to which BF ₃ / methanol complex and Sumilizer MDP-S were added so that the amount of hydroquinone was 100 ppm. , And the photocurable adhesive composition of Example 6 were obtained.

(Example 7)
The purified iBuCA of Example 7 was prepared in the same manner as in Example 3 except that hydroquinone was added to the purified iBuCA to which BF ₃ / methanol complex and Sumilizer MDP-S were added so that the amount of hydroquinone was 40 ppm. , And the photocurable adhesive composition of Example 7 were obtained.

(Example 8)
Purified iBuCA of Example 8 was prepared in the same manner as in Example 3 except that hydroquinone was added to purified iBuCA to which BF ₃ / methanol complex and Sumilizer MDP-S were added so that the amount of hydroquinone was 100 ppm. , And the photocurable adhesive composition of Example 8 were obtained.

<Evaluation of storage stability in Examples 1 and 4>
The obtained photocurable adhesive composition was placed in a hermetically sealed container and stored in a thermostatic chamber at 60 ° C., and the viscosity at the initial stage and after 4 days, 7 days, 14 days, 21 days and 28 days was elapsed. Was measured respectively.
The evaluation results are summarized in Table 2.

As shown in Table 2, the photocurable adhesive compositions of Examples 1 and 4 and the obtained 2-cyanoacrylate compound (2-OctCA) were prepared from conventional Group 8 transition metal metallocene compounds and 2- It has better storage stability than a photocurable adhesive composition containing a cyanoacrylate compound.

<Evaluation of storage stability in Examples 2, 5 and 6>
The obtained photocurable adhesive composition was placed in a sealed container and stored in a thermostatic chamber at 60 ° C., and the viscosities at the initial stage and at the elapsed time of 2 days and 6 days were respectively measured.
The evaluation results are summarized in Table 3.

As shown in Table 3, the photocurable adhesive compositions of Examples 2, 5 and 6 and the obtained 2-cyanoacrylate compound (EtOEtCA) were prepared from conventional Group 8 transition metal metallocene compounds and 2- It has better storage stability than a photocurable adhesive composition containing a cyanoacrylate compound.

<Evaluation of storage stability in Examples 3, 7 and 8>
The obtained photocurable adhesive composition was placed in a sealed container and stored in a thermostatic chamber at 60 ° C., and the viscosities at the initial stage and at the elapsed time of 3 days and 24 days were measured, respectively.
The evaluation results are summarized in Table 4.

As shown in Table 4, the photocurable adhesive compositions of Examples 3, 7 and 8 and the obtained 2-cyanoacrylate compound (iBuCA) were prepared from conventional Group 8 transition metal metallocene compounds and 2- It has better storage stability than a photocurable adhesive composition containing a cyanoacrylate compound.

The disclosure of Japanese Patent Application No. 2018-199573 filed on Oct. 23, 2018 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually noted to be incorporated by reference. Are incorporated herein by reference.

Claims (7)

1. A depolymerization step of depolymerizing a 2-cyanoacrylate polycondensate, which is a condensate of a cyanoacetic acid ester compound and a formaldehyde compound, under the presence of a polymerization inhibitor and under heating and reduced pressure conditions to obtain a crude 2-cyanoacrylate monomer. When,
   A step of distilling the crude 2-cyanoacrylate monomer to obtain a purified 2-cyanoacrylate monomer,
   The method for producing a 2-cyanoacrylate compound, wherein the radical polymerization inhibitor used as the polymerization inhibitor in the depolymerization step is a compound having no hydroquinone structure.
2. The method for producing a 2-cyanoacrylate compound according to claim 1, wherein the radical polymerization inhibitor contains a compound represented by the following formula (1).
   

   

   
   In formula (1), R ₁ to R ₅ are each independently a hydrogen atom or a substituent other than a hydroxy group (excluding a phenolic hydroxy group) which may combine with each other to form a ring. Represent
3. The method for producing a 2-cyanoacrylate compound according to claim 1 or 2, further comprising a step of adding a polymerization inhibitor after the step of adding a radical polymerization inhibitor to the purified 2-cyanoacrylate monomer after the distillation purification step.
4. The method for producing a 2-cyanoacrylate compound according to claim 3, wherein the radical polymerization inhibitor added in the post-addition step of the polymerization inhibitor is a phenolic radical polymerization inhibitor.
5. The method for producing a 2-cyanoacrylate compound according to claim 3 or 4, wherein the radical polymerization inhibitor added in the post-addition step of the polymerization inhibitor is a radical polymerization inhibitor having a hydroquinone structure.
6. 6. The amount of the radical polymerization inhibitor added in the post-addition step of the polymerization inhibitor is 10 ppm to 1,000 ppm in the obtained 2-cyanoacrylate compound, according to any one of claims 3 to 5. Method for producing 2-cyanoacrylate compound.
7. A photocurable adhesive composition comprising a mixing step of mixing a 2-cyanoacrylate compound obtained by the production method according to any one of claims 1 to 6 with a Group 8 transition metal metallocene compound. Production method.