JP7255606B2 - Method for producing 2-cyanoacrylate compound and method for producing photocurable adhesive composition - Google Patents

Description

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 initiates polymerization with a minute amount of moisture present 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. And because of its strong adhesive strength, it is used as a main component of instant adhesives in a wide range of fields such as electrical, electronic, machine parts, precision machinery, household goods and medical care.

As conventional methods for producing 2-cyanoacrylate compounds, 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 liquid in a depolymerization reactor having a stirrer is changed during the reaction. A process for the production of 2-cyanoacrylate is described, characterized in that the depolymerization reaction is carried out while keeping constant.

Further, in Patent Document 2, in depolymerizing a condensate of cyanoacetate and formaldehyde in the presence of a polymerization inhibitor, from the fraction obtained by depolymerization, a high boiling point fraction that condenses above the boiling point of 2-cyanoacrylate A process for the production of 2-cyanoacrylate is described, characterized in that the components are returned to the depolymerization reaction and depolymerized.

Further, Patent Document 3 discloses a method for producing 2-cyanoacrylate, which includes a step of depolymerizing a condensate of cyanoacetate and formaldehyde, and a step of purifying the obtained crude 2-cyanoacrylate by distillation, wherein the depolymerization A method for producing 2-cyanoacrylate, characterized in that the temperature of the partial condenser in the process is 10° C. or more higher than the boiling point of 2-cyanoacrylate at that pressure, and the high boiling point acid content is partially removed at 50° C. or less. Are listed.

Furthermore, in Patent Document 4, a step of introducing a cyanoacetic ester and formalin into a reaction tank to perform a polycondensation reaction, a step of introducing the obtained polycondensation reaction liquid into a dehydration tank and dehydrating it, and a dehydrated polycondensation A step of continuously introducing the reaction solution into the thin film evaporator for desolubilization and a step of continuously introducing the desolubilized polycondensate into the thin film evaporator for depolymerization are continuously carried out. , The dehydration tank is divided into two or more dehydration tanks connected in series, and after introducing the polycondensation reaction liquid into the first dehydration tank among the plurality of connected dehydration tanks, a solvent is added to perform azeotropic dehydration. A method for continuous production of 2-cyanoacrylate is described, which is characterized by performing

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

A 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 manufacturing method of
Another problem to be solved by the present invention is to provide a method for producing a photocurable adhesive composition using the 2-cyanoacrylate compound obtained by the method for producing the 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 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. a depolymerization step;
a distillation purification step of distilling the crude 2-cyanoacrylate monomer to obtain a purified 2-cyanoacrylate monomer;
A 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 each independently represent a hydrogen atom or a substituent other than a hydroxy group (excluding a phenolic hydroxy group), which may be combined to form a ring. show.

<3> The 2-cyanoacrylate compound according to <1> or <2>, including a polymerization inhibitor post-addition step of adding a radical 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 polymerization inhibitor post-adding step 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 polymerization inhibitor post-adding step is a radical polymerization inhibitor having a hydroquinone structure. .
<6> Any one of <3> to <5>, wherein the addition amount of the radical polymerization inhibitor in the polymerization inhibitor post-adding step is 10 ppm to 1,000 ppm in the resulting 2-cyanoacrylate compound. A method for producing a 2-cyanoacrylate compound according to .
<7> A photocurable adhesive comprising 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 of making the composition.

According to the present invention, 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 is provided. can provide.
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 representative embodiments of the present invention, but the present invention is not limited to such embodiments. In the specification of the present application, the term "~" is used to mean that the numerical values before and after it are included as the lower limit and the upper limit.
In the numerical ranges described stepwise in this specification, the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit of the numerical range described in other steps. good. Moreover, in the numerical ranges described in this specification, the upper and lower limits of the numerical ranges may be replaced with the values 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 otherwise specified when there are multiple substances corresponding to each component in the composition. do.
In the present invention, the term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved.
In the present invention, "% by mass" and "% by weight" are synonymous, and "parts by mass" and "parts by weight" are synonymous.
Moreover, in the present invention, a combination of two or more preferred aspects is a more preferred aspect.
Moreover, in this specification, "(meth)acryloyl" represents both or either of acryloyl and methacryloyl, and "(meth)acryloxy" represents both or either of acryloxy and methacryloxy.
Furthermore, in some of the compounds herein, the hydrocarbon chain may be represented by a simplified structural formula that omits the symbols for carbon (C) and hydrogen (H).
The contents of the present invention will be described in detail below.

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

In conventional methods 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 found that when a compound having a hydroquinone structure is used in depolymerization, the compound having a hydroquinone structure is oxidized by the action of impurities and decomposed products, and a compound having a benzoquinone structure is produced, albeit in a very small amount. 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, the 2-cyanoacrylate having excellent storage stability of the 2-cyanoacrylate compound obtained by using only a compound having no hydroquinone structure as the polymerization inhibitor in the depolymerization step We have 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. A compound represented by the following formula (C) is preferred.

In formula (C), R is a saturated or unsaturated linear 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.
provided, however, that when R contains an ether bond, either or both of the ether-bonded hydrocarbon residues are saturated or unsaturated straight hydrocarbon chains having 5 to 20 carbon atoms which may have a halogen atom. A chain hydrocarbon group, a branched chain hydrocarbon group, a cyclic hydrocarbon group, or an aromatic group having 5 to 20 carbon atoms which may have a halogen atom.

Specific examples of 2-cyanoacrylate compounds include methyl, ethyl, chloroethyl, n-propyl, i-propyl, allyl, propargyl, n-butyl, i-butyl, n-pentyl and n-hexyl of 2-cyanoacrylate. , 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-dimethylcyclohexyl, 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, 2-hexyloxyethyl, 2-cyclohexyloxyethyl, 2-(2-ethylhexyloxy)ethyl, and ester compounds such as 2-phenoxyethyl. Moreover, these are preferably used as a main component or a subcomponent of a cyanoacrylate adhesive.

Among these, 2-cyanoacrylate compounds include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, cyclohexyl, phenyl, tetrahydrofurfuryl, 2-ethylhexyl, 2-cyanoacrylate, n-octyl, 2-octyl, 2-methoxyethyl, 2-ethoxyethyl ester or 1-(2-methoxy-1-methylethoxy)propyl are preferred.

From the viewpoint of storage stability, 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 the content of a compound having a benzoquinone structure is It is preferably greater than 0 ppm and less than 4 ppm.
Compounds 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, 3-dichloro-5,6-dicyanobenzoquinone, 2-hydroxy-1,4-naphthoquinone, 2-methyl-1,4-naphthoquinone, 2-chloro-1,4-naphthoquinone, 1,4-dihydroxyanthraquinone, etc. be done.

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

In the depolymerization step, a 2-cyanoacrylate polycondensate, which is a condensate of a cyanoacetic ester compound and a formaldehyde compound, is used. Also, the 2-cyanoacrylate polycondensate in the present disclosure is depolymerized to produce a 2-cyanoacrylate monomer (2-cyanoacrylate compound).
The cyanoacetic 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 compounds include formaldehyde gas, formalin aqueous solution, reaction products of formaldehyde and alcohol, paraformaldehyde, trioxane, and the like.
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), A compound represented by the following formula (2) is particularly preferred.

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

In formula (1), from the viewpoint of storage stability, at least one of R ₁ to R ₅ is preferably the above substituent, more preferably at least R ₁ and R ₅ are the above substituents, and R ₁ , R ₃ and R ₅ are particularly preferably 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 An alkyl group having a structure is more preferred, and _R1 is a linear or branched alkyl group, and _R5 is particularly preferably an alkyl group having a (meth)acryloxyphenyl structure.
From the viewpoint of storage stability, R ₃ in 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 even more 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 an alkyl group having 1 to 6 carbon atoms. It is more preferably 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, and a methyl group, a t-butyl group, or 2 -methyl-2-butyl group is particularly preferred.
The alkyl group may be linear, branched, or have a cyclic structure, and may have a substituent.
Examples of the substituent include a halogen atom, an alkoxy group, an aryl group, and the like, as long as the group does not lose the ability to inhibit polymerization. Also, the substituent may be further substituted with at least one 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, 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, more preferably a hydrogen atom or a methyl group.
From the viewpoint of storage stability, R ₇ and R ₁₀ in formula (2) are preferably tertiary alkyl groups, more preferably tertiary alkyl groups having 4 to 8 carbon atoms, and t- A butyl group or a 2-methyl-2-butyl group is particularly preferred.
From the viewpoint of storage stability, R ₈ and R ₉ in formula (2) are preferably alkyl groups having 1 to 8 carbon atoms, such as methyl group, t-butyl group, 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.

In addition, the 5% weight loss temperature under a nitrogen atmosphere of the polymerization inhibitor used in the depolymerization step is in the range of −150° C. to +50° C. relative to the boiling point of the 2-cyanoacrylate compound used. is preferred.

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( 4,6-di-tert-amylphenol) monoacrylate (253° C.) and at least selected from the group consisting of 2,2′-methylenebis(6-(1-methylcyclohexyl)-p-cresol) (285° C.) A single compound is preferred. The temperatures in parentheses are all 5% weight loss temperatures.

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

In the depolymerization step, depolymerization is preferably performed in the presence of a depolymerization catalyst from the viewpoint of depolymerization speed and depolymerization yield.
Preferred examples of the depolymerization catalyst include diphosphorus pentoxide, phosphoric acid, polyphosphoric acid, p-toluenesulfonic acid, and the like, from the viewpoint of depolymerization rate and depolymerization yield. Diphosphorus is more preferred.
Moreover, the depolymerization catalyst may have an ability to inhibit polymerization. For example, diphosphorus pentoxide, phosphoric acid, polyphosphoric acid, and p-toluenesulfonic acid are depolymerization catalysts with the ability to inhibit polymerization. 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 amount of the depolymerization catalyst used in the depolymerization step is, from the viewpoint of the depolymerization rate and the depolymerization yield, 0.5 parts per 100 parts by mass of the 2-cyanoacrylate polycondensate used. 05 parts by mass to 20 parts by mass, more preferably 0.1 parts by mass to 10 parts by mass, and particularly preferably 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, diphenylphenyl phosphonate, etc. may be added in order to reduce the viscosity in the reaction vessel during depolymerization.
In the depolymerization step, one type of the high boiling point solvent may be used alone, or two or more types may be used.
In addition, the amount of the high boiling point solvent used in the depolymerization step is 0.5 parts per 100 parts by mass of the 2-cyanoacrylate polycondensate used, from the viewpoint of depolymerization rate and depolymerization yield. It is preferably from 1 part by mass to 50 parts by mass, more preferably from 1 part by mass to 30 parts by mass, and particularly preferably from 2 parts by mass to 20 parts by mass.

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

Specifically, the depolymerization step can be suitably performed by, for example, the following method.
A 2-cyanoacrylate polycondensate, which is a condensate of cyanoacetate and formaldehyde, is introduced into a reactor equipped with a cooler for cooling the fraction, and the temperature is gradually raised under reduced pressure. When the inside of the reactor reaches the temperature at which the depolymerization reaction starts, 2-cyanoacrylate monomer gas begins to come out, and the inside temperature of the reactor is kept higher than the reaction-initiating temperature to continue depolymerization.
The cooler maintains a temperature at which the gas produced by depolymerization can be condensed. In this case, the temperature of the cooler is preferably a temperature below the boiling point of the 2-cyanoacrylate monomer under partial condensation pressure conditions, for example, preferably in the range of -30°C to 50°C.
Condensed by the cooler, the condensed fraction is recovered to obtain crude 2-cyanoacrylate monomer.
Moreover, in the depolymerization step, it is also preferable to perform the depolymerization while refluxing.
Furthermore, 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 condensed above the boiling point of the 2-cyanoacrylate monomer is used. The fraction may be returned to the depolymerization reaction for depolymerization.
Although the above example describes a batch-type depolymerization apparatus, a continuous depolymerization apparatus can also be applied to the present invention.

<Distillation purification 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 purification step, trace amounts of water remaining in the crude 2-cyanoacrylate monomer and impurities such as polymers can be removed to obtain a purified 2-cyanoacrylate monomer.
When the crude 2-cyanoacrylate monomer contains an organic solvent, it is preferable to distill off the organic solvent before carrying out the main distillation to obtain the purified 2-cyanoacrylate monomer.
The pressure during the distillation in the distillation purification step is not particularly limited, and may be appropriately selected depending on the heating temperature and the boiling point of the 2-cyanoacrylate monomer, etc., but it is preferably under reduced pressure, 10 Pa to 13 Pa, 300 Pa is more preferable.
In addition, the heating temperature during the distillation in the distillation purification step is not particularly limited, and may be appropriately selected according to the pressure during distillation and the boiling point of the 2-cyanoacrylate monomer, etc., but it is 30 ° C. to 150 ° C. is preferred, and 40°C to 100°C is more preferred.

Moreover, 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.
Preferred examples of the polymerization inhibitor added in the distillation purification step include anionic polymerization inhibitors such as diphosphorus pentoxide, SO ₂ , p-toluenesulfonic acid, methanesulfonic acid, propanesultone, and BF ₃ complex. As the BF ₃ complex, ether complexes, alcohol complexes, carboxylic acid complexes and the like are preferably mentioned.
Among them, the polymerization inhibitor added in the distillation purification step preferably contains diphosphorus pentoxide from the viewpoint of yield and storage stability.
In addition, the radical polymerization inhibitor added as the polymerization inhibitor in the distillation purification step is preferably a compound that does not have a hydroquinone structure from the viewpoint of storage stability when the photocurable adhesive composition is prepared. preferable.

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

Distillation in the distillation purification step can be performed by a known method.
The crude 2-cyanoacrylate monomer obtained by the depolymerization step can be directly introduced to the distillation purification step, and the distillation purification step can be continuously performed at the same time as the depolymerization step.

In addition, the method for producing a 2-cyanoacrylate compound of the present invention is preferably carried out in an atmosphere with no or little moisture and oxygen (for example, 0.01% by volume or less), more preferably in an inert gas atmosphere. preferable.
Nitrogen, argon, etc. are mentioned as an inert gas.

<Polymerization inhibitor post-addition process>
From the viewpoint of storage stability, the method for producing a 2-cyanoacrylate compound of the present invention preferably includes a polymerization inhibitor post-addition step of adding a polymerization inhibitor after the distillation purification step.
After the distillation 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, resulting in excellent storage stability.
From the viewpoint of storage stability, the polymerization inhibitor added in the polymerization inhibitor post-adding step is preferably a phenol-based radical polymerization inhibitor. Examples of the phenolic 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 species selected from the group consisting of hydroquinone, methylhydroquinone, methoxyhydroquinone, 2,6-dimethylhydroquinone and 2,6-di-tert-butylhydroquinone, which are radical polymerization inhibitors having a hydroquinone structure. At least one is particularly preferred.

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

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

The method for adding the polymerization inhibitor in the polymerization inhibitor post-adding step is not particularly limited, and the polymerization initiator may be added to the purified 2-cyanoacrylate monomer. A method of previously adding the purified 2-cyanoacrylate monomer to a vessel for collecting it, or a method of adding it after completion of distillation may be mentioned.
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 at the same time as the distillation purification step. It is also possible to

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

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

The said basic catalyst may be used individually by 1 type, or may use 2 or more types together.
The amount of the basic catalyst added in the polycondensation step is not particularly limited, but from the viewpoint of reactivity and yield, it is 0.0001 part by mass to 0.01 part by mass with respect to 100 parts by mass of the cyanoacetic ester compound. is preferably

A solvent is preferably used in the polycondensation step.
Solvents used in the polycondensation step include toluene, xylene, benzene, trichlorethylene, cyclohexane, ethyl acetate, methanol, ethanol, isopropanol, tricresyl phosphate, dioctyl phthalate, diphenylphenyl phosphonate and the like.
The solvents may be used singly or in combination of two or more.
Moreover, the amount of the solvent to be used is not particularly limited, and may be appropriately selected as desired.

In addition, the 2-cyanoacrylate polycondensate obtained by the polycondensation step is subjected to a known appropriate pretreatment so that it can be decomposed well into 2-cyanoacrylate monomers in the subsequent depolymerization step. may be
As the pretreatment, for example, water contained in the raw material or water generated during the condensation step is removed by azeotropy when a solvent that forms an azeotropic mixture with water is used, otherwise A treatment of distilling off is preferred. The basic catalyst used is preferably subjected to a treatment such as inactivation with an acidic substance, removal by washing with water, or removal 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 the 2-cyanoacrylate compound obtained by the production method of the present invention, and the 2-cyanoacrylate compound obtained by the production method of the present invention and Group 8 and a transition metal metallocene compound.
Further, the method for producing a 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 the 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 respective components described above and below, but there is no or little moisture and oxygen (for example, 0.01% by volume or less). ) atmosphere, more preferably in an inert gas atmosphere.
Nitrogen, argon, etc. are mentioned as an inert gas.
Moreover, the method for producing the photocurable resin composition of the present invention is preferably carried out under light shielding conditions.
The mixing method is not particularly limited, and known mixing methods 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. Preferably, it does not contain a compound with a benzoquinone structure, or the content of a compound with a benzoquinone structure is more preferably more than 0 ppm and 3 ppm or less, and it does not contain a compound with a benzoquinone structure, or has a benzoquinone structure. It is more preferable that the content of the compound having the compound is more than 0 ppm and 1.5 ppm or less.
When the photocurable adhesive composition of the present invention contains two or more compounds having a benzoquinone structure, the content is the total content of the two or more compounds having a benzoquinone structure.

<Group 8 transition metal metallocene compound>
The photocurable adhesive composition of the present invention preferably contains a Group 8 transition metal metallocene compound.
The Group 8 transition metal metallocene compound is presumed to function as a photopolymerization initiator. Furthermore, since the light absorption wavelength of the Group 8 transition metal metallocene compound is also on the long wavelength side of 500 nm or longer, the photocurable adhesive composition of the present invention can be used in a wider wavelength range, that is, in the ultraviolet range and the visible range. Photocuring is possible even with light in the optical range.

Examples of the Group 8 transition metal metallocene compound include ferrocene compounds in which the transition metal is iron, osmocene compounds in which the transition metal is osmium, ruthenocene compounds in which the transition metal is ruthenium, cobaltocene compounds in which cobalt is used, and nickelocene compounds in which the transition metal is nickel. Mention may be made of metallocene compounds having Group 8 transition metal elements 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 ferrocene, ethylferrocene, n-butylferrocene, benzoylferrocene, acetylferrocene, t-amylferrocene, 1,1′-dimethylferrocene, and 1,1′. -di-n-butylferrocene, 1,1'-dibenzoylferrocene, 1,1'-di(acetylcyclopentadienyl)iron, bis(pentamethylcyclopentadienyl)iron, bis(cyclopentadienyl) Examples include osmium, bis(pentamethylcyclopentadienyl)osmium, ruthenocene (bis(cyclopentadienyl)ruthenium), and bis(pentamethylcyclopentadienyl)ruthenium.
As the Group 8 transition metal metallocene compound, a transition metal metallocene compound of Group 8 of the periodic table having an aromatic electronic 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. and particularly preferably at least one compound selected from the group consisting of ferrocene and ruthenocene.

The photocurable adhesive composition of the present invention may contain one group VIII transition metal metallocene compound alone, or may contain two or more 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 10 ppm to 10 ppm, from the viewpoint of photocurability and storage stability. ,000 ppm, and particularly preferably between 20 ppm and 2,000 ppm.

<2-cyanoacrylate compound>
The photocurable adhesive composition of the invention contains a 2-cyanoacrylate compound obtained by the production method of the invention.
The photocurable adhesive composition of the present invention may contain one type of 2-cyanoacrylate compound alone, or may contain 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 60% by mass or more, from the viewpoint of curability, adhesion speed, and adhesion strength. It is more preferable to have

<Photoradical 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 for photopolymerizing a radically polymerizable compound can be used.
Examples of photoradical generators include acylgermane-based compounds, acylphosphine oxide-based compounds, acetophenone-based compounds having no hydroxyl group, nitrogen atom and thioether bond, and benzoin-based compounds having no hydroxyl group, nitrogen atom and thioether bond. be done.
Among them, acylgermane-based compounds are preferable as the photoradical generator from the viewpoint of photocurability, adhesion speed, and storage stability.

As the acylgermane compound, monoacylgermane compounds and bisacylgermane compounds are preferred, and bisacylgermane compounds are more preferred.
Preferred examples of acylgermane compounds include Ivocerin (manufactured by Ivoclar Vivadent).

As acylphosphine oxide compounds, monoacylphosphine oxide compounds and bisacylphosphine oxide compounds are preferred, and bisacylphosphine oxide compounds are more preferred.
Preferred monoacylphosphine oxide compounds 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 of 1 to represents a phenyl group substituted with an alkyl group of 8 or an alkoxy group of 1 to 8 carbon atoms, and R ^A3 is a linear or branched alkyl group of 1 to 18 carbon atoms which is unsubstituted or substituted by 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 unsubstituted or substituted with a halogen atom; or the following formula (A-2) represents the group represented.

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

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, methylacylphenylphosphonate, isobutyroyldiphenylphosphine oxide, 2-methylhexanoyl diphenylphosphine oxide, o-toluyldiphenylphosphine oxide, pt-butylbenzoyldiphenylphosphine oxide, 3-polydylcarbonyldiphenylphosphine oxide, acryloyldiphenylphosphine oxide, benzoyldiphenylphosphine oxide, adiboylbis(diphenylphosphine oxide) and the like. .

As the bisphosphine oxide-based compound, a compound represented by the following formula (A-3) is preferable.

R ^p in formula (A-3) is unsubstituted, 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 may be the same can be different.

The alkyl group having 1 to 12 carbon atoms in R ^p in formula (A-3) may be linear or branched, for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl , tert-butyl, pentyl, isopentyl, hexyl, heptyl, octyl, nonyl, decyl or dodecyl groups. An alkyl group having 1 to 6 carbon atoms is preferable, and an alkyl group having 1 to 4 carbon atoms is more preferable.
The alkylthio group having 1 to 8 carbon atoms in R ^p in formula (A-3) may be linear or branched, such as methylthio, ethylthio, propylthio, isopropylthio, butylthio, tert-butylthio, Hexylthio or octylthio may be mentioned. Among them, methylthio is preferred.
Halogen atoms include, for example, chlorine, bromine, and iodine atoms. Among them, a chlorine atom is preferred.

Bisacylphosphine oxide compounds include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide.

Acetophenone compounds include 4-phenoxydichloroacetophenone, 4-t-butyldichloroacetophenone, 4-t-butyltrichloroacetophenone, diethoxyacetophenone and the like.
Benzoin compounds include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl methyl ketal and the like.

Among these, the photoradical generator is dibenzoyldiethylgermanium, bis(4-methoxybenzoyl)dimethylgermanium, bis(4-methoxybenzoyl)diethylgermanium from the viewpoint of photocurability, adhesion speed, 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, dibenzoyldiethylgermanium, bis(4-methoxybenzoyl)dimethylgermanium, bis(4-methoxybenzoyl)diethylgermanium, bis(4-methylbenzoyl)diethylgermanium, bis(4-methylbenzoyl)dimethylgermanium and dibenzoyl More preferably, it is at least one compound selected from the group consisting of dibutyl germanium.

The photocurable adhesive composition of the present invention may contain one kind of photoradical generator alone or two or more kinds thereof.
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. 0.01% to 5% by mass, more preferably 0.05% to 2% by mass, and particularly preferably 0.05% to 1% by mass.

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

Preferred examples of the polymerization inhibitor include anionic polymerization inhibitors having no hydroquinone structure, such as diphosphorus pentoxide, SO ₂ , p-toluenesulfonic acid, methanesulfonic acid, propanesultone, and BF ₃ complex.

As the polymerization inhibitor, a polymerization inhibitor having no hydroquinone structure, such as the compound represented by the formula (1) or (2), is preferably used.
Polymerization inhibitors having no hydroquinone structure include, from the viewpoint of storage stability, mekinol, 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) is preferably at least one selected from the group consisting of.

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

The addition of the radical polymerization inhibitor having a hydroquinone structure is more preferably during the preparation of the photocurable adhesive composition or after distillation purification during the production of the raw material 2-cyanoacrylate compound. More preferably during preparation of the curable adhesive composition.

The photocurable adhesive composition of the present invention may contain one type of polymerization inhibitor alone, or may contain two or more types. Among them, from the viewpoint of storage stability, it is preferable to contain an anionic polymerization inhibitor that does not have a hydroquinone structure, and it is more preferable to contain a radical polymerization inhibitor that does not have a hydroquinone structure and an anionic polymerization inhibitor that does not have a 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, more preferably 20 ppm to 5,000 ppm, based on the total mass of the photocurable adhesive composition.
The content of the radical polymerization inhibitor having a hydroquinone structure is preferably 10 ppm or more and 1000 ppm or less, more preferably 20 ppm or more and 500 ppm or less.

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

Examples of anionic polymerization accelerators include polyalkylene oxides, crown ethers, silacrown ethers, calixarenes, cyclodextrins and pyrogallol-based cyclic compounds. Polyalkylene oxides are polyalkylene oxides and derivatives thereof, for example, JP-B-60-37836, JP-B-1-43790, JP-A-63-128088, JP-A-3-167279 Publications, US Pat. No. 4,386,193, US Pat. No. 4,424,327 and the like are disclosed. Specifically, (1) polyalkylene oxides 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 and diethylene glycol. Derivatives of polyalkylene oxide such as dialkyl ether, dipropylene glycol monoalkyl ether, dipropylene glycol dialkyl ether, and the like are included. Examples of crown ethers include those disclosed in JP-B-55-2236, JP-A-3-167279, and the like. 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-decaryl-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-5 and the like. Examples of silacrown ethers include those disclosed in JP-A-60-168775. Specific examples include dimethylsila-11-crown-4, dimethylsila-14-crown-5, dimethylsila-17-crown-6 and the like. Examples of calixarenes include those disclosed in JP-A-60-179482, JP-A-62-235379 and JP-A-63-88152. Specifically, 5,11,17,23,29,35-hexa-tert-butyl-37,38,39,40,41,42-hexahydroxycalix[6]allene, 37,38,39, 40,41,42-hexahydroxycalix[6]allene, 37,38,39,40,41,42-hexa-(2-oxo-2-ethoxy)-ethoxycalix[6]allene, 25,26, 27,28-tetra-(2-oxo-2-ethoxy)-ethoxycalix[4]allene, tetrakis(4-t-butyl-2-methylenephenoxy)ethyl acetate and the like. Cyclodextrins include, for example, those disclosed in Japanese Patent Publication No. 5-505835. Specific examples include α-, β- or γ-cyclodextrin. Examples of pyrogallol-based cyclic compounds include compounds disclosed in JP-A-2000-191600. 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. One of these anionic polymerization accelerators may be used alone, or two or more thereof may be used in combination.

A plasticizer can be contained as long as the effects of the present invention are not impaired.
Examples of this plasticizer include acetyl triethyl citrate, acetyl tributyl citrate, dimethyl adipate, diethyl adipate, dimethyl sebacate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisodecyl phthalate, dihexyl phthalate, 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 cyclohexyl carboxylate, diisobutyl fumarate, diisobutyl maleate, caproic acid triglyceride, 2-ethylhexyl benzoate, dipropylene glycol dibenzoate and the like. Among these, acetyl tributyl citrate, dimethyl adipate, dimethyl phthalate, 2-ethylhexyl benzoate, and dipropylene glycol are preferred because of their good compatibility with 2-cyanoacrylate and high plasticization efficiency. Dibenzoates are 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, it is preferably 3 parts by mass to 50 parts by mass, more preferably 10 parts by mass to 45 parts by mass. , 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 thermal cycle test.

Furthermore, as thickeners, polymethyl methacrylate, copolymers of methyl methacrylate and acrylic acid esters, copolymers of methyl methacrylate and other methacrylic acid esters, acrylic rubber, polyvinyl chloride, polystyrene, Cellulose esters, polyalkyl-2-cyanoacrylic acid esters, ethylene-vinyl acetate copolymers, and the like. These thickeners may be used alone or in combination of two or more.

The photocurable adhesive composition of the present invention can also contain fumed silica.
The fumed silica is ultrafine anhydrous silica (preferably having a primary particle size of 500 nm or less, particularly preferably 1 nm to 200 nm). An ultrafine anhydrous silica (preferably having a primary particle size of 500 nm or less, particularly preferably 1 nm to 200 nm) produced due to oxidation in a gas phase state, a highly hydrophilic hydrophilic silica, and a hydrophobic with highly hydrophobic silica. Any of these fumed silicas can be used, but hydrophobic silicas are preferred from the viewpoint of good dispersibility in the 2-cyanoacrylate compound.

As the hydrophilic silica, various commercially available products can be used, for example, Aerosil 50, 130, 200, 300 and 380 (these are trade names, 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 and 380±30 m ² /g, respectively. As commercially available hydrophilic silica, Rheolosil QS-10, QS-20, QS-30 and QS-40 (the above are trade names, manufactured by Tokuyama Co., Ltd.) 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, commercially available hydrophilic silica such as manufactured by CABOT can also be used.

Furthermore, as the hydrophobic silica, a compound capable of reacting with a hydroxyl group present on the surface of the hydrophilic silica to form a hydrophobic group, or a compound adsorbed on the surface of the hydrophilic silica and capable of forming a hydrophobic layer on the surface. Products produced by contacting a compound with hydrophilic silica in the presence or absence of a solvent, preferably by heating, and treating the surface of hydrophilic silica can be used.

Compounds used to surface-treat hydrophilic silica to make it hydrophobic include various alkyl, aryl, and aralkyl silane coupling agents having hydrophobic groups such as n-octyltrialkoxysilane, methyltrichlorosilane, dimethyldichlorosilane, Examples 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, products hydrophobized using any compound may be used.

Commercially available hydrophobic silicas include, for example, Aerosil RY200 and R202 surface-treated and hydrophobized with silicone oil, Aerosil R974, R972 and R976 surface-treated and hydrophobized with a dimethylsilylating agent, Aerosil R805 surface-treated with methoxysilane and hydrophobized, Aerosil R811 and R812 surface-treated with a trimethylsilylating agent and hydrophobized (these are trade names, manufactured by Nippon Aerosil Co., Ltd.) and methyl tri Reolosil MT-10 (trade name, Tokuyama Co., Ltd.) surface-treated with chlorosilane to make it hydrophobic, and the like. 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.

A preferable content of fumed silica in the photocurable adhesive composition of the present invention is 1 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 fumed silica, etc., but is 1 part by mass to 25 parts by mass, and a particularly preferred content is 2 parts by mass to 20 parts by mass. Department. If the content of the fumed silica is 1 part by mass to 30 parts by mass, the adhesive composition can be made to have good workability without impairing the curability and adhesive strength of the photocurable adhesive composition. can.

The method for curing the photocurable adhesive composition of the present invention is not particularly limited as long as the 2-cyanoacrylate compound can be polymerized and cured. good.
When the photocurable adhesive composition of the present invention is cured by light, it is possible to irradiate ultraviolet rays or visible rays 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 by

The photocurable adhesive composition of the present invention may be stored by a known storage method. mixing is preferred, and mixing in an inert gas atmosphere is more preferred.
Nitrogen, argon, etc. are mentioned as an inert gas.
Moreover, 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 or as a photocurable adhesive composition.
For example, it can be used as a so-called instant adhesive, or it can be used as a photocurable instant adhesive.
INDUSTRIAL APPLICABILITY The photocurable adhesive composition of the present invention is photocurable and moisture-curable and has excellent storage stability. .
Specifically, for example, sealing of electronic parts, attachment of reel seats and threading guides to fishing rods, fixing of wire materials such as coils, fixing of magnetic heads to pedestals, fillings used in dental treatment It can be suitably used for bonding or fixing between articles of the same or different types, such as adhesive agents, artificial nails, or decoration, or for coating.

EXAMPLES The present invention will be specifically described below based on examples. It should be noted that the present invention is not limited by these examples. Further, hereinafter, "parts" and "%" mean "mass parts" 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. 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 in the depolymerization reactor under a reduced pressure of 1,000 Pa or less while maintaining the internal temperature at 150°C to 200°C. The fraction was condensed with a condenser and crude 2-OctCA was collected in a collection receiver. Depolymerization was terminated when crude 2-OctCA ceased to distill.

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

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

(Example 2)
<Production of 2-ethoxyethyl ester of 2-cyanoacrylic acid (EtOEtCA)>
A depolymerization reactor equipped with a cooler 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. 3.5 parts by mass of GS was added to 100 parts by mass of the condensate.

Depolymerization was carried out in the depolymerization reactor under a reduced pressure of 1,000 Pa or less while maintaining the internal temperature at 150°C to 200°C. The fractions were condensed by a condenser and crude EtOEtCA was collected in a collection receiver. The depolymerization was terminated when no more crude EtOEtCA was distilled.

To the obtained 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 are added per 100 parts by mass of crude EtOEtCA and distilled to remove impurities with low boiling points. Purified EtOEtCA was obtained after distilling off as .
To the obtained purified EtOEtCA, 20 ppm of BF ₃ ·methanol complex and 1,000 ppm of MDP-S (the compound described below) were added to the whole.
The total yield from the condensate was 35%.
The acid content (acid content (μg equivalent)) per 1 g of purified EtOEtCA obtained was 0.12 μg.

<Production of photocurable adhesive composition>
In the same manner as in Example 1, except that purified EtOEtCA to which BF ₃ ·methanol complex and sumilizer MDP-S were added was used instead of purified 2-OctCA to which BF ₃ ·methanol complex and sumilizer MDP-S were added. , the photocurable adhesive composition of Example 2 was prepared.

(Example 3)
<Production of 2-cyanoacrylic acid isobutyl ester (iBuCA)>
A depolymerization reactor equipped with _a cooler and a stirrer was charged with 100 parts by mass of a condensate of isobutyl cyanoacetate and _{paraformaldehyde} . 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 in the depolymerization reactor under a reduced pressure of 1,000 Pa or less while maintaining the internal temperature at 150°C to 200°C. The fraction was condensed by a condenser and crude iBuCA was collected in a collection receiver. Depolymerization was terminated when crude iBuCA ceased to distill.

To the obtained crude iBuCA, 0.5 parts by mass of diphosphorus pentoxide and 1.0 part by mass of MDP-S were added per 100 parts by mass of crude iBuCA and distilled to remove impurities with low boiling points as initial distillation. , to obtain purified iBuCA.
To the obtained purified iBuCA, 20 ppm of BF ₃ ·methanol complex and 1,000 ppm of MDP-S (the compound described below) were added to the whole.
The total yield from the condensate was 40%.
The acid content (acid content (μg equivalent)) per 1 g of purified iBuCA obtained was 0.19 μg.

<Production of photocurable adhesive composition>
In the same manner as in Example 1, except that purified iBuCA added with BF ₃ ·methanol complex and Sumilizer MDP-S was used instead of purified 2-OctCA added with BF ₃ ·methanol complex and Sumilizer MDP-S. , the photocurable adhesive composition of Example 3 was prepared.

Table 1 summarizes the details of the production methods of the 2-cyanoacrylate compounds in Examples 1 to 3.

(Example 4)
Example 4 was prepared in the same manner as in Example 1 except that hydroquinone was added to the purified 2-OctCA to which BF ₃ ·methanol complex and Sumilizer MDP-S were added so that the amount of hydroquinone was 40 ppm with respect to the entire composition. Purified 2-OctCA and the photocurable adhesive composition of Example 4 were obtained, respectively.

(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 as to be 40 ppm with respect to the entire composition. , and the photocurable adhesive composition of Example 5, respectively.

(Example 6)
The purified EtOEtCA of Example 6 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 as to be 100 ppm with respect to the entire composition. , and the photocurable adhesive composition of Example 6, respectively.

(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 the BF ₃ ·methanol complex and Sumilizer MDP-S were added so as to be 40 ppm with respect to the entire composition. , and the photocurable adhesive composition of Example 7, respectively.

(Example 8)
The purified iBuCA of Example 8 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 as to be 100 ppm with respect to the entire composition. , and the photocurable adhesive composition of Example 8, respectively.

<Storage stability evaluation in Examples 1 and 4>
The resulting photocurable adhesive composition was placed in a sealed container and stored in a constant temperature room at 60°C. were measured respectively.
Table 2 summarizes the evaluation results.

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

<Storage stability evaluation in Examples 2, 5 and 6>
The resulting photocurable adhesive composition was placed in a sealed container and stored in a constant temperature room at 60° C., and the viscosity was measured at the initial stage and at the time points of 2 days and 6 days after the lapse of time.
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 resulting 2-cyanoacrylate compounds (EtOEtCA) were mixed with conventional Group 8 transition metal metallocene compounds and 2- It has better storage stability than a photocurable adhesive composition containing a cyanoacrylate compound.

<Storage stability evaluation in Examples 3, 7 and 8>
The resulting photocurable adhesive composition was placed in a sealed container and stored in a constant temperature room at 60° C., and the viscosity was measured at the initial stage, and after 3 days and 24 days of elapsed time.
Table 4 summarizes the evaluation results.

As shown in Table 4, the photocurable adhesive compositions of Examples 3, 7 and 8 and the resulting 2-cyanoacrylate compounds (iBuCA) were mixed with 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 October 23, 2018 is incorporated herein by reference in its entirety.
All publications, patent applications and technical standards mentioned herein are to the same extent as if each individual publication, patent application or technical standard were specifically and individually noted to be incorporated by reference. , incorporated herein by reference.

Claims (8)

A depolymerization step of depolymerizing a 2-cyanoacrylate polycondensate, which is a condensate of a cyanoacetic ester compound and a formaldehyde compound, in the presence of a polymerization inhibitor under heating and reduced pressure conditions to obtain a crude 2-cyanoacrylate monomer. and,
a distillation purification step of distilling the crude 2-cyanoacrylate monomer to obtain a purified 2-cyanoacrylate monomer;
The radical polymerization inhibitor used as the polymerization inhibitor in the depolymerization step is one or more compounds selected from compounds represented by the following formula (2) having no hydroquinone structure: 2-cyanoacrylate compound manufacturing method.

In formula (2), R ₆ represents a hydrogen atom or an alkyl group, R ₇ to R ₁₀ each independently represent an alkyl group, a cycloalkyl group or an alkenyl group, R ₁₁ represents a hydrogen atom or ( meth) represents an acryloyl group. The radical polymerization inhibitor, the 5% weight loss temperature under nitrogen atmosphere, with respect to the boiling point of the 2-cyanoacrylate compound used, containing compounds in the range of -150 ° C. ~ +50 ° C., according to claim 1. A method for producing a 2-cyanoacrylate compound. The radical polymerization inhibitor is 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-methyl cyclohexyl)-p-cresol). 4. The 2-cyanoacrylate according to any one of claims 1 to 3 , comprising a polymerization inhibitor post-addition step of adding a radical polymerization inhibitor to the purified 2-cyanoacrylate monomer after the distillation purification step. A method for producing a compound. 5. The method for producing a 2-cyanoacrylate compound according to claim 4 , wherein the radical polymerization inhibitor added in the polymerization inhibitor post-adding step is a phenol-based radical polymerization inhibitor. 6. The method for producing a 2-cyanoacrylate compound according to claim 4 , wherein the radical polymerization inhibitor added in the polymerization inhibitor post-addition step is a radical polymerization inhibitor having a hydroquinone structure. The addition amount of the radical polymerization inhibitor in the polymerization inhibitor post-adding step is 10 ppm to 1,000 ppm in the resulting 2-cyanoacrylate compound, according to any one of claims 4 to 6 . A method for producing a 2-cyanoacrylate compound. 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 7 and a Group 8 transition metal metallocene compound Production method.