JP2003212856A - Photobase generator, curable composition and method for curing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photobase generator capable of maintaining characteristics of a conventional photocuring technique, having high efficiency of catalyst production and a catalytic activity and excellent pot life, a curable composition and a method for curing. <P>SOLUTION: This photobase generator is an imidazolium salt compound represented by general formula (1) or (2) and generating a base by irradiation with light of 150-750 nm. The curable composition comprises at least an epoxy resin and the imidazolium salt compound. The method for curing comprises carrying out only irradiation with light or simultaneous irradiation with light and heating or heating after the irradiation with light and thereby providing a cured product. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to 150 to 750n
The present invention relates to a photobase generator that generates a base upon irradiation with light of m, a curable composition using the same, and a curing method.

[0002]

2. Description of the Related Art Photo-curing technology is applied to coatings, resists, etc. by taking advantage of its characteristics such as low-temperature curing, process shortening, short-time curing, and microfabrication as compared with conventional heat curing technology. . Curing systems mainly used for photocuring are roughly classified into radical curing and cationic curing. In the case of radical curing, with photo radical generator (meta)
Acrylate resin is the main component, and the photo-radical generator generates radicals through processes such as cleavage and hydrogen abstraction during light irradiation to cure the (meth) acrylate resin, enabling rapid curing. It is a feature. In the case of cation curing, it is composed of a photo-acid generator and a cationically polymerizable epoxy resin, oxetane resin, vinyl ether resin, etc., and the photo-acid generator generates an acid upon light irradiation to cure the cation-polymerizable resin. It is a system and has the characteristic of low cure shrinkage during curing. In addition, these photo-curing systems are characterized by having an excellent pot life by shielding light. However, in the case of a radical curing system, a low adhesive force is obtained, and in the case of a cation curing system, a strong acid remains in the system, so that there is a problem that corrosion is caused when an adherend made of a metal or an inorganic material is used. Conventionally, for applications such as adhesives, a thermal latent catalyst having a basic group such as imidazole or dicyandiamide and an epoxy resin, or a carboxyl group, a mercapto group, an amino group, a phenolic hydroxyl group, etc. which are reactive with the epoxy resin. A combined heat curing system is used. This system has high adhesion to adherends such as inorganic materials, metal materials, organic materials, etc., and also has excellent moisture resistance, weather resistance, and heat resistance, so it can be used for construction materials, electrical / electronic materials, and semiconductor materials. It is used in a wide range of applications. However, when the latent curing agent is used,
Generally, a curing temperature of 170 ° C or higher is required, and 170 ° C
When curing at the temperatures below, it is difficult to build a curing system that also has a pot life. Considering pot life and low-temperature curability, studies on photobase generators that generate basic compounds by light irradiation have been conducted in recent years. Examples of such a photobase generator include, for example, Chemistry & Te.
chnology of UV & EBFormul
ation for Coatings, Inks
& Paints, Ed. by G.A. Bradle
y, John Wiley and Sons Ltd.
(1998), p479 to p545, carbamate derivatives and oxime ester derivatives are generally known. However, most of these compounds have low generation efficiency, and since the basic compound generated by light irradiation is a primary or secondary amine, they have low basicity and have a catalytic activity for sufficiently curing an epoxy resin. There is no problem. Some compounds that generate a strong base upon irradiation with light have been reported, for example, JP-A-55-
Carboxylic acid ammonium salts described in JP-A-22669 and α-described in JP-A-11-71450
An aminoacetophenone derivative is mentioned.

[0003]

However, in the case of an ammonium carboxylic acid salt, the bond between the carboxylic acid and the tertiary amine is an ionic bond. Therefore, when dissolved in the epoxy curable composition, dissociation proceeds and the pot It has the disadvantage of inferior life. Further, in the case of α-aminoacetophenone derivative, although the catalyst is inactivated by steric hindrance in the molecule, when dissolved in the epoxy curable composition, free rotation in the molecule becomes possible, resulting in pot life. I know it's inferior.

The present invention provides a photobase generator, a curable composition, and a curing method which maintain the characteristics of conventional photocuring technology, have high catalyst generation efficiency, have catalytic activity, and have excellent pot life. To do.

[0005]

Means for Solving the Problems The inventors of the present invention have made earnest studies in view of the above circumstances, and as a result, the imidazolium salt compound has an excellent pot life and generates imidazole which is a strong base upon irradiation with light to give 170 ° C. It has been found that the epoxy resin can be cured at the following low temperatures. The present invention is 150 to 7
The present invention relates to an imidazolium salt compound represented by the general formula (1) or (2), which is characterized by generating a base upon irradiation with light of 50 nm.

[0006]

[Chemical 5] (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are independently hydrogen and carbon number 1
~ 8 alkyl group, C1-8 alkoxy group, C1-8 alkylidene group, C4-8 cycloalkyl group, C4-8 cycloalkenyl group, C1
To C6 phenoxyalkyl group, C1 to C6 phenylalkyl group, C1 to C6 cyanoalkyl group, C1 to C6 hydroxyalkyl group, phenyl group, electron donating group and / or electron withdrawing property A phenyl group substituted with a group, a benzyl group, a benzyl group substituted with an electron-donating group and / or an electron-withdrawing group, a nitro group, a cyano group, a mercapto group, a thiomethyl group, fluorine, bromine, chlorine, or iodine.

Ar ₁ is an aromatic group represented by the general formula (I) to (XIV),

[Chemical 6] In the formula, R _{5 to} R ₂₈ are independently hydrogen, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkylthio group having 1 to 8 carbon atoms, an alkylidene group having 1 to 8 carbon atoms, and carbon. Cycloalkyl group having 4 to 8 carbon atoms, cycloalkenyl group having 4 to 8 carbon atoms, amino group, alkylamino group having 1 to 6 carbon atoms, dialkylamino group having 1 to 3 carbon atoms, morpholino group, mercapto group, hydroxyl group, Hydroxyalkyl group having 1 to 6 carbon atoms, halogen such as fluorine, chlorine and bromine, carbon number
1-6 ester group, carbonyl group having 1-6 carbon atoms, aldehyde group, cyano group, trifluoromethyl group, cyano group, nitro group, phenyl group, electron-donating group and / or electron-withdrawing group substituted A benzyl group substituted with a phenyl group, an electron-donating group and / or an electron-withdrawing group. Further, in the formula, A to F represent any of carbon, nitrogen, oxygen and sulfur atoms. Ar ₂ is represented by the following formulas (XV) to (XXII
An aromatic group represented by I),

[0008]

[Chemical 7] R _{29 to} R ₃₆ are independently hydrogen, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkylthio group having 1 to 8 carbon atoms, an alkylidene group having 1 to 8 carbon atoms, and 4 carbon atoms. ~ 8 cycloalkyl group, C4-8 cycloalkenyl group, amino group, C1-6 alkylamino group, C1-3 dialkylamino group, morpholino group, mercapto group, hydroxyl group, carbon number 1 to 6 hydroxyalkyl group, halogen such as fluorine, chlorine and bromine, ester group having 1 to 6 carbon atoms, carbonyl group having 1 to 6 carbon atoms, aldehyde group, cyano group, trifluoromethyl group, cyano group, nitro A phenyl group, a phenyl group, a phenyl group substituted with an electron-donating group and / or an electron-withdrawing group, and a benzyl group substituted with an electron-donating group and / or an electron-withdrawing group. Further, in the formula, A to D are independently any of carbon, nitrogen, oxygen and sulfur atoms, and they are carbon, nitrogen and carbon number 1
You may combine with the alkyl group of -6, oxygen, and sulfur. X- is a dialkyldithiocarbamic acid having 1 to 6 carbon atoms, thiocyanate, or boric acid represented by the following formula (XXIV).

[Chemical 8] R _{37 to} R ₄₀ are independently hydrogen, fluorine, and 1 to 6 carbon atoms.
Is an alkyl group, a phenyl group, a fluorophenyl group in which at least one of fluorine is substituted, or an imidazole group.

Examples of the alkyl group having 1 to 8 carbon atoms include methyl group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, sec-butyl group, tert-butyl group,
Examples thereof include a pentyl group, iso-pentyl group, neo-pentyl group, hexyl group, heptyl group and octyl group. Carbon number 1
As the alkoxy group of ~ 8, methoxy group, ethoxy group, n-propoxy group, iso-propoxy group, n-butoxy group, sec-butoxy group, pentyloxy group, iso-pentyloxy group, neo-pentyloxy group, Examples thereof include a hexyloxy group, a heptyloxy group and an octyloxy group. Examples of the alkylidene group having 1 to 8 carbon atoms include, for example,
Methylidene group, ethylidene group, n-propylidene group, is
Examples thereof include o-propylidene group, n-butylidene group, sec-butylidene group, tert-butylidene group, pentylidene group, iso-pentylidene group, neo-pentylidene group, hexylidene group, heptylidene group and octylidene group. 4 to 4 carbon atoms
Examples of the cycloalkyl group of 8 include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group. Carbon number 4-8
Examples of the cycloalkenyl group include a cyclobutenyl group, a cyclopentenyl group, a cyclohexenyl group, a cycloheptynyl group, and a cyclooctenyl group. As the phenoxyalkyl group having 1 to 6 carbon atoms, for example,
Phenoxymethyl group, phenoxyethyl group, phenoxy-n-propyl group, phenoxy-iso-propyl group, phenoxy-n-butyl group, phenoxy-sec-butyl group, phenoxy-tert-butyl group, phenoxypentyl group, phenoxy-iso group -Pentyl group, phenoxy-neo-pentyl group,
A phenoxyhexyl group may be mentioned. Examples of the phenylalkyl group having 1 to 6 carbon atoms include phenylmethyl group, phenylethyl group, phenyl-n-propyl group, phenyl-iso-propyl group, phenyl-n-butyl group, phenyl-sec-butyl group, Phenyl-tert-butyl group, phenylpentyl group, phenyl-iso-pentyl group, phenyl-
Examples thereof include neo-pentyl group and phenylhexyl group. Examples of the cyanoalkyl group having 1 to 6 carbon atoms include cyanomethyl group, cyanoethyl group, cyano-n-propyl group,
Cyano-iso-propyl group, cyano-n-butyl group, cyano-sec-butyl group, cyano-tert-butyl group, cyanopentyl group, cyano-iso-pentyl group, cyano-neo-pentyl group, cyanohexyl group Can be mentioned. 1 to 6 carbon atoms
Examples of the hydroxyalkyl group include hydroxymethyl group, hydroxyethyl group, hydroxy-n-propyl group, hydroxy-iso-propyl group, hydroxy-n-butyl group, hydroxy-sec-butyl group, hydroxy-tert-group.
-Butyl group, hydroxypentyl group, hydroxy-iso-
Examples thereof include a pentyl group, a hydroxy-neo-pentyl group and a hydroxyhexyl group. Examples of the alkylthio group having 1 to 8 carbon atoms include methylthio group, ethylthio group, n-
Examples thereof include propylthio group, iso-propylthio group, n-butylthio group, sec-butylthio group, tert-butylthio group, pentylthio group, iso-pentylthio group, neo-pentylthio group, hexylthio group, heptylthio group and octylthio group. Examples of the alkylamino group having 1 to 6 carbon atoms include, for example, aminomethyl group, aminoethyl group, amino-n-propyl group, amino-iso-propyl group, amino-n-butyl group, amino-sec-butyl group, Amino-tert-butyl group,
Examples thereof include an amino-pentyl group, an amino-iso-pentyl group, and an amino-neo-pentyl group. Examples of the dialkylamino group having 1 to 3 carbon atoms include a dimethylamino group, a diethylamino group, a di-n-propylamino group and a di-iso-propylamino group. Examples of the electron donating group include an amino group, a hydroxyl group, halogen (chlorine, bromine, iodine, etc.), an alkyl group and the like. Examples of the electron-withdrawing group include a nitro group, a carbonyl group, a carboxyl group, a nitrile group and the like.

The present invention is also a curable composition containing at least an epoxy resin and an imidazolium salt compound represented by the above general formula (1) or (2). Further, the present invention is a curable composition comprising an epoxy resin, an imidazolium salt compound represented by the general formula (1) or (2), and a compound having two or more functional groups reactive with the epoxy resin in the molecule. Is. Further, the present invention is the above curable composition, wherein the functional group reactive with the epoxy resin is a carboxyl group, a mercapto group, a phenolic hydroxyl group, a primary or secondary aromatic amino group. The present invention also includes a compound having two or more isocyanate groups in the molecule, an imidazolium salt compound represented by the general formula (1) or (2), and a compound having two or more hydroxyl groups in the molecule. It is a curable composition. Further, the present invention is a curing method for obtaining a cured product by curing only the light-curable composition, or heating the composition at the same time or after the light-irradiation.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The imidazolium salt compound used in the present invention is represented by the above general formula (1) or (2), wherein R ₁ , R ₂ , R ₃ and R ₄ are independently hydrogen or carbon. An alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkylidene group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 8 carbon atoms, a cycloalkenyl group having 4 to 8 carbon atoms, and 1 to 1 carbon atoms 6-phenoxyalkyl group, C1-C6 phenylalkyl group, C1-C6 cyanoalkyl group, C1-C6 hydroxyalkyl group, phenyl group, electron-donating group and / or electron-withdrawing group Represents a phenyl group substituted with benzyl, a benzyl group, a benzyl group substituted with an electron-donating group and / or an electron-withdrawing group, a nitro group, a cyano group, a mercapto group, a thiomethyl group, fluorine, bromine, chlorine or iodine. Ar ₁ in the general formula (1) is represented by the general formula (I) to
(XIV) is an aromatic group,

[Chemical 9] In the formula, R _{5 to} R ₂₈ are independently hydrogen, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkylthio group having 1 to 8 carbon atoms, an alkylidene group having 1 to 8 carbon atoms, and carbon. Cycloalkyl group having 4 to 8 carbon atoms, cycloalkenyl group having 4 to 8 carbon atoms, amino group, alkylamino group having 1 to 6 carbon atoms, dialkylamino group having 1 to 3 carbon atoms, morpholino group, mercapto group, hydroxyl group, Hydroxyalkyl group having 1 to 6 carbon atoms, halogen such as fluorine, chlorine and bromine, ester group having 1 to 6 carbon atoms, carbonyl group having 1 to 6 carbon atoms, aldehyde group, cyano group, trifluoromethyl group, cyano group , A nitro group, a phenyl group, a phenyl group substituted with an electron-donating group and / or an electron-withdrawing group, and a benzyl group substituted with an electron-donating group and / or an electron-withdrawing group. Further, in the formula, A to F are any of carbon, nitrogen, oxygen and sulfur atoms. Ar ₂ in the general formula (2) is
An aromatic group represented by the following formulas (XV) to (XXIII),

[Chemical 10] R _{29 to} R ₃₆ are independently hydrogen, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkylthio group having 1 to 8 carbon atoms, an alkylidene group having 1 to 8 carbon atoms, and 4 carbon atoms. ~ 8 cycloalkyl group, C4-8 cycloalkenyl group, amino group, C1-6 alkylamino group, C1-3 dialkylamino group, morpholino group, mercapto group, hydroxyl group, carbon number 1 to 6 hydroxyalkyl group, halogen such as fluorine, chlorine and bromine, ester group having 1 to 6 carbon atoms, carbonyl group having 1 to 6 carbon atoms, aldehyde group, cyano group, trifluoromethyl group, cyano group, nitro A phenyl group, a phenyl group, a phenyl group substituted with an electron-donating group and / or an electron-withdrawing group, and a benzyl group substituted with an electron-donating group and / or an electron-withdrawing group. Further, in the formula, A to D are independently any of carbon, nitrogen, oxygen and sulfur atoms, and they are carbon, nitrogen and carbon number 1
You may combine with the alkyl group of -6, oxygen, and sulfur. Further, X − in the general formulas (1) and (2) is a dialkyldithiocarbamic acid having 1 to 6 carbon atoms, thiocyanate, or boric acid represented by the following formula (XXIV).

[Chemical 11] R _{37 to} R ₄₀ are independently hydrogen, fluorine, and 1 to 6 carbon atoms.
Is an alkyl group, a phenyl group, a fluorophenyl group in which at least one of fluorine is substituted, or an imidazole group.

A known method can be used for the synthesis of the imidazolium salt compound. Considering the convenience and safety of the synthesis, as shown in the formula below, the halogenated alkyl ketone derivative and the imidazole derivative are
After synthesizing the halogen salt, by anion exchange reaction,
A method of synthesizing an imidazolium salt is preferred.

[Chemical 12] The synthesis temperature and the synthesis time are not particularly limited as long as the starting materials used are not decomposed, but generally 0 to
The desired imidazolium salt compound can be obtained by stirring at 100 ° C. for 30 minutes to 7 days.

A compound (epoxy resin) having at least two epoxy groups in the molecule used in the present invention
There is no particular limitation as long as it has two or more epoxy groups in the molecule, and known ones can be used. Among the compounds having an epoxy group used in the present invention, examples of the compound having two epoxy groups in one molecule include the compounds shown below (Me is a methyl group, and the broken line is a methylene group in some cases). .

[0014]

[Chemical 13]

[0015]

[Chemical 14]

Among the compounds having an epoxy group used in the present invention, examples of the compound having three epoxy groups in one molecule include the compounds shown below (Me
Represents a methyl group, Et represents an ethyl group, and a broken line represents a methylene group in some cases).

[0017]

[Chemical 15]

Further, among the compounds having an epoxy group used in the present invention, examples of the compound having four epoxy groups in one molecule include the compounds shown below.

[Chemical 16]

As the compound having an epoxy group used in the present invention, a compound represented by the general formula (3) can also be used.

[Chemical 17] In the general formula (3), R ^{8 to} R ¹¹ each independently represents a hydrogen atom, a halogen atom such as fluorine, chlorine, bromine or iodine, or a monovalent group. Examples of the monovalent group include amino groups, ester groups such as carbomethoxy groups, amide groups such as carboaminomethyl groups, carbamino groups such as aminocarboxymethyl groups, substituted or unsubstituted methyl groups, ethyl groups and propyl groups. Examples thereof include an alkyl group such as a butyl group, a hexyl group, and a heptyl group or a substituted or unsubstituted phenyl group, a vinyl group, a 1-propenyl group, an alkenyl group such as a 1-butenyl group, and a silyl group.

As the compound having an epoxy group in the present invention, a compound having an epoxy group having an epoxy equivalent of 43 to 10,000 may be used. If the epoxy equivalent is 43 or less, the crosslink density tends to decrease, and if it exceeds 10,000, the reaction rate tends to decrease. Also,
At this time, when not only a single molecule but also an oligomer having a distribution in the number of repeating units (z) as shown below is used, the crystallinity of the composition is lowered and the storage stability is excellent. Therefore, 0 <z is preferable, 0.5 ≦ z is more preferable, and
1 ≦ z is most preferable.

[0021]

[Chemical 18]

The compound having at least two epoxy groups in the molecule is bisphenol A.
Type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol F novolac type epoxy resin, alicyclic epoxy resin, glycidyl ester Type epoxy resin, glycidyl amine type epoxy resin, hydantoin type epoxy resin, isocyanurate type epoxy resin, aliphatic chain epoxy resin, etc., and these epoxy resins may be halogenated or hydrogenated. Good. Two or more of these epoxy resins may be used in combination. Among these, bisphenol type epoxy resins are preferable because grades having different molecular weights are widely available as compared with other various epoxy compounds, and adhesiveness, reactivity and the like can be arbitrarily set.

The imidazolium salt compound can be generally used as a curing catalyst for an epoxy resin, and the amount of the imidazolium salt compound used is 0.
The amount is preferably 01 to 50 parts by weight, and 0.1 to 30
It is more preferable to set it as a weight part. This amount is 0.01
If it is less than parts by weight, the curing acceleration effect tends to be insufficient, and if it exceeds 50 parts by weight, the compatibility tends to decrease.

In the present invention, the epoxy resin and the imidazolium salt compound may be used in combination with a compound having two or more functional groups reactive with the epoxy resin in the molecule. As the functional group having reactivity with the epoxy resin, a carboxyl group, a mercapto group, a phenolic hydroxyl group, a primary or secondary aromatic amino group known to react with the epoxy resin can be used. . Considering three-dimensional curability, it is essential that two or more of these functional groups be contained in one molecule. Further, a polymer having a weight average molecular weight of 10,000 or more and a functional group introduced into a side chain may be used.

The amount of the compound having two or more functional groups reactive with the epoxy resin in the molecule is 0.5 based on the total amount of the functional groups / the total amount of the epoxy groups (equivalent ratio) with respect to the epoxy resin. /1.5 to 1.5 / 0.5 is preferable, and 0.8 / 1.2 to 1.2 /
It is more preferable that the ratio is 0.8. If this ratio is less than 0.5 / 1.5 and 1.5 / 0.
When it exceeds 5, a large amount of unreacted epoxy groups and functional groups remain in the cured product, which tends to deteriorate the mechanical properties of the cured product.

The present invention can also be applied as a curable composition composed of a compound having an isocyanate group, a compound having a hydroxyl group, and the imidazolium salt compound. The compound having an isocyanate group (hereinafter referred to as an isocyanate resin) used in the present invention is not particularly limited as long as it has two or more isocyanate groups in the molecule, and known compounds can be used. Such compounds include p-phenylene diisocyanate, 2,
4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,5-naphthalene diisocyanate,
In addition to a low molecular weight compound represented by hexamethylene diisocyanate, a polymer having a weight average molecular weight of 3,000 or more and an isocyanate group at the side chain or terminal may be used.

The compound having an isocyanate group is usually used in combination with a compound having a hydroxyl group in the molecule. Such an isocyanate resin is not particularly limited as long as it has two or more hydroxyl groups in the molecule,
Known ones can be used. Such compounds include:
In addition to low molecular weight compounds such as ethylene glycol, propylene glycol, glycerin, diglycerin, and pentaerythritol, those having a hydroxyl group at the side chain or terminal of a polymer having a weight average molecular weight of 3,000 or more may be used.

The amount of the compound having two or more hydroxyl groups in the molecule is 0.5 / total amount of hydroxyl groups / total amount of isocyanate groups (equivalent ratio) with respect to the above isocyanate resin.
The ratio is preferably 1.5 to 1.5 / 0.5, and more preferably 0.8 / 1.2 to 1.2 / 0.8. This ratio is 0.5
When it is less than /1.5 and exceeds 1.5 / 0.5, a large amount of unreacted epoxy groups and functional groups remain in the cured product, which tends to deteriorate the mechanical properties of the cured product. is there.

The amount of the imidazolium salt compound used as a curing catalyst for the isocyanate resin and the compound having a hydroxyl group is 0.01 to 50 parts by weight based on 100 parts by weight of the total amount of the compound having an isocyanate group and the compound having a hydroxyl group. It is preferable that it is 0.1 to 30 parts by weight. If this amount is less than 0.01 parts by weight,
The curing acceleration effect tends to be insufficient, and if it exceeds 50 parts by weight, the compatibility tends to decrease.

The curable composition of the present invention may be used in combination with a sensitizer for the purpose of high absorption of irradiation light and high sensitivity. As the sensitizer to be used, a known singlet sensitizer or triplet sensitizer can be used as long as it does not adversely affect the curable composition. For example, aromatic compound derivatives such as naphthalene, anthracene, and pyrene, carbazole derivatives, benzophenone derivatives, thioxanthone derivatives, and coumarin derivatives are preferably used. The amount of the sensitizer to be used needs to be based on the absorption wavelength and the molar extinction coefficient of the sensitizer, but is generally 0. 1 with respect to 1 part of the imidazolium salt compound.
01 to 5 parts, and 0.1 to 2 parts are particularly preferable. When the sensitizer is less than 0.01 part, the efficiency of light absorption becomes low,
If it is 5 parts or more, light may not reach the entire curable composition.

The curable composition of the present invention may optionally contain additives such as an adhesion improver such as a coupling agent, a leveling agent and an organic or inorganic filler.

Various polymers may be appropriately added to the curable composition of the present invention for the purpose of thickening or forming a film. The polymer to be used is not particularly limited, but it is essential that it does not adversely affect the curability. Examples of such polymers include general-purpose phenoxy resins such as polyimide, polyamide, bisphenol A-type phenoxy resin, bisphenol F-type phenoxy resin, and bisphenol A / bisphenol F copolymerization-type phenoxy resin, polymethacrylates, polyacrylates, polyimides. , Polyurethanes, polyesters, polyvinyl butyral, SB
S and its epoxy modified products, SEBS and its modified products, etc. can be used. These may be used alone or in combination of two or more. Furthermore, these polymers may contain a siloxane bond or a fluorine substituent. These can be suitably used as long as the resins to be mixed are completely compatible with each other, or microphase separation occurs to cause clouding. The molecular weight is not particularly limited, but as a general weight average molecular weight, 5,000 to 150,000 is preferable and 10,000
~ 80,000 is particularly preferred. This value is 5,000
If it is less than 15, the film formability tends to be inferior.
If it exceeds 50,000, the compatibility with other components tends to deteriorate. The amount used is preferably 20 to 320 parts by weight with respect to 100 parts by weight of the epoxy resin or the isocyanate resin.

The curable composition of the present invention has a room temperature (25 ° C.).
When it is liquid, it can be used as a paste. When it is solid at room temperature, it may be used by heating, or may be made into a paste by using a solvent. The solvent that can be used is not particularly limited as long as it does not adversely affect the curability and exhibits sufficient solubility, but a solvent having a boiling point of 50 to 150 ° C. under normal pressure is preferable. Boiling point is 50
If it is below ℃, it may volatilize if left at room temperature.
Limited use in open systems. If the boiling point is 150 ° C or higher, it may be difficult to remove the solvent.

The curable composition of the present invention can be used in the form of a film. A solution obtained by adding a solvent or the like to the curable composition is applied onto a releasable base material such as a fluororesin film, a polyethylene terephthalate film or a release paper, or a base material such as a non-woven fabric is impregnated with the solution. It can be used as a film by removing the solvent and the like by placing it on a peelable substrate. When used in the form of a film, it is even more convenient in terms of handleability.

The curable composition of the present invention can be cured by irradiation with light alone, simultaneous irradiation with light and heating, or heating after irradiation with light. Light irradiation is 150-7
Irradiation light in the wavelength range of 50 nm is preferable, and a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a xenon lamp, and a metal halide lamp are used for 0.1 to 100 J.
It can be cured at an irradiation dose of / cm ² . The heating temperature is not particularly limited as long as it is equal to or lower than the decomposition point of the epoxy resin to be used and the compound having a functional group reactive with the epoxy resin, but a temperature of 30 to 200 ° C. is preferable and 5
0-170 degreeC is more preferable. Further, the heating time is 1 second to 3 hours, preferably 30 seconds to 1 hour in order to sufficiently perform the curing.

The curable composition of the present invention comprises a paint, an adhesive,
It can be applied to a wide variety of applications such as inks, photoresists, coating materials, various automobile parts, electric / electronic materials, semiconductor materials, optical materials, optical fibers, adhesives for optical fibers, and optical waveguide materials. Especially regarding adhesives, in addition to adhesion of wood, building materials, plastics, leather, etc.
Used as anisotropic conductive adhesive, circuit paste such as silver paste, silver film, etc., and semiconductor element adhesive material such as flip chip anisotropic conductive material for connecting semiconductor elements such as flip chips and printed wiring boards. can do.

[0037]

EXAMPLES The present invention will be specifically described below based on examples, but the present invention is not limited thereto.

Example 1 Synthesis of imidazolium salt 1 Phenacyl bromide (2.00 g, 10.5 mmol)
Was dissolved in acetone (20 g) and acetone (5 g) was added to it.
1-benzyl-2-methylimidazole dissolved in
A solution of (1.73 g, 10.5 mmol) was slowly added, and then the mixture was stirred at room temperature (25 ° C.) for 2 hours, whereupon white crystals were precipitated. This is filtered and 2 with acetone
After washing twice, it was dried under vacuum at 60 ° C. for 5 hours to obtain imidazolium bromide salt 1 (yield 3.54).
g). The imidazole bromide salt 1 (2.00
g, 5.4 mmol) to methanol / water (15 g / 15
g) Sodium tetraphenylborate (1.84 g, 5.4 g) dissolved in a solution and dissolved in water (5.0 g).
4 mmol) solution was added slowly. Precipitation in the form of a white slurry was observed with the addition, and after the addition, the mixture was further stirred at room temperature for 5 hours. This precipitate was filtered, dissolved in acetone (20 g) and recrystallized to obtain the desired imidazolium / tetraphenylborate salt (imidazolium salt 1) (yield 2.86 g). ¹ H- of this compound
NMR is shown in FIG. Further, when the melting point and the thermal decomposition starting temperature in an oxygen atmosphere were measured by TG-DTA, the melting point was 187 ° C and the decomposition starting temperature was 224 ° C.

Example 2 Synthesis of Imidazolium Salt 2 p-Nitrophenacyl Bromide (2.00 g, 8.2)
1,2-dimethylimidazole dissolved in acetone (20 g) and then dissolved in acetone (5 g)
A solution of (0.79 g, 8.2 mmol) was slowly added, and then the mixture was stirred at room temperature for 2 hours, whereupon white crystals were precipitated. This was filtered, washed twice with acetone, and then dried under vacuum at 60 ° C. for 5 hours to obtain imidazolium bromide salt 2 (yield 2.62 g). The imidazole bromide salt 2 (2.00 g, 5.8 mm
ol) was dissolved in a methanol / water (15 g / 15 g) solution, and tetraphenyl boric acid sodium salt (2.01 g, 5.8 mmol) was dissolved in water (5.0 g).
Was slowly added. Precipitation in the form of a white slurry was observed with the addition, and after the addition, the mixture was further stirred at room temperature for 5 hours. This was filtered, dissolved in acetone (20 g) and recrystallized to obtain the desired imidazolium tetraphenylborate (imidazolium salt 2) (yield 2.83 g). ¹ H-NMR of this compound is shown in FIG. Further, when the melting point and the thermal decomposition starting temperature in an oxygen atmosphere were measured by TG-DTA, the melting point was 165 ° C and the decomposition starting temperature was 195 ° C.

(Example 3) DER736 on epoxy resin
(Product name of Dow Chemical Co., epoxy equivalent 172):
1.00 g, pentaerythritol tetra (mercaptoacetate) as a mercapto compound (manufactured by Tokyo Chemical Industry Co., Ltd., SH group equivalent 108): 0.614 g, Example 1
Imidazolium salt of 1: 0.016 g was mixed at room temperature to form a uniform solution. 3 mg of this in the sample pan of DSC
Sampled so that
C was measured. The light irradiation is the UV irradiation device AEL 1B / M (365 nm illuminance: 21.5 mW / made by Fusion).
cm ² ), and 3 J / cm ² irradiation was performed.

Example 4 The DSC measurement was performed in the same manner as in Example 3 except that the imidazolium salt compound in Example 2 was used instead of the imidazolium salt compound.

(Comparative Example 1) The DSC measurement was performed in the same manner as in Example 3 except that the light irradiation was not performed.

(Comparative Example 2) The DSC measurement was carried out in the same manner as in Example 4 except that the light irradiation was not carried out.

The results of Examples 3 and 4 and Comparative Examples 1 and 2 are shown in Table 1. In addition, the reaction start temperature in the table was an Onset temperature indicating an exothermic start temperature.

The curable compositions of Examples 3 and 4 show that the curing reaction proceeds at a low temperature of 30 ° C. or higher as compared with Comparative Examples 1 and 2, and that the imidazolium salt compound becomes basic when exposed to light. It shows that a compound is generated and low temperature curing is possible.

[0046]

[Table 1]

(Example 5) Synthesis of imidazolium salt 3 Phenacyl bromide (2.00 g, 10.5 mmol)
Was dissolved in acetone (20 g) and acetone (5 g) was added to it.
1-benzyl-2-methylimidazole dissolved in
A solution of (1.73 g, 10.5 mmol) was slowly added, and then the mixture was stirred at room temperature for 2 hours, whereupon white crystals were precipitated. This was filtered, washed twice with acetone, and then dried under vacuum at 60 ° C. for 5 hours to obtain imidazolium bromide salt 3 (yield 3.54 g). The imidazole bromide salt 3 (2.00 g, 5.4 mm
ol) was dissolved in ethanol (50 g), and this was dissolved in ethanol (20 g) dithiocarbamic acid sodium salt dihydrate (1.33 g, 5.4 mmol).
Was slowly added. After the addition, the mixture was refluxed for 20 minutes to cause a reaction, and the solvent was distilled off, whereby a yellow powder was deposited. This was recrystallized three times with ethanol (20 g) to obtain the desired imidazolium dithiocarbamate salt (imidazolium salt 3) (yield 1.80 g). ¹ H-NMR of this compound is shown in FIG. Further, when the melting point and the thermal decomposition starting temperature in an oxygen atmosphere were measured by TG-DTA, the melting point was 181 ° C and the decomposition starting temperature was 168 ° C.

Example 6 0.14 g of the imidazolium salt 3 obtained in Example 5 and 1.00 g of polyglycidyl methacrylate (Mn: 138,000, Mw / Mn: 1.49) were weighed and weighed. 21. Mixed solvent adjusted to have a ratio of cyclohexanone / acetonitrile: 5/2.
It was dissolved in 7 g. After spin coating the above solution on a silicon wafer to a film thickness of 1 μm, UV irradiation was performed on the entire surface using a high pressure mercury lamp. Then, it was immersed in THF at room temperature for 3 minutes, and the residual film thickness on the silicon wafer was measured.

The results of Example 6 are shown in Table 2. The residual film rate in the table is defined as the film thickness after development × 100 / the film thickness after spin coating (1 μm).

Since the residual film rate increases with the increase of the UV irradiation amount, the imidazolium salt 3 is exposed by the UV irradiation.
Generated a base and promoted the crosslinking of polyglycidyl methacrylate.

[0051]

[Table 2]

Example 7 Synthesis of Imidazolium Salt 4 Phenacyl bromide (2.00 g, 10.5 mmol)
Was dissolved in acetone (20 g) and acetone (5 g) was added to it.
1-methylimidazole (0.82 g, 1 dissolved in
(0.5 mmol) was slowly added thereto, and then the mixture was stirred at room temperature for 2 hours, whereupon white crystals were precipitated.
This was filtered, washed twice with acetone, and then dried under vacuum at 60 ° C. for 5 hours to obtain imidazolium bromide salt 4 (yield 2.76 g). The above imidazole bromide salt 4 (2.76 g, 9.8 mmol) was dissolved in ethanol (20 g), and sodium thiocyanate (0.88 g, 9.9 mmol) was slowly added thereto. After the addition, the reaction was carried out at room temperature for 60 minutes and the solvent was distilled off, whereby a white powder was deposited. Add this to ethanol (2
Recrystallization was performed 3 times with 0 g) to obtain the desired imidazolium thiocyanate salt (imidazolium salt 4) (yield 1.71 g). ¹ H-NMR of this compound is shown in FIG. Further, the melting point in an oxygen atmosphere was measured and found to be 74-76 ° C.

(Example 8) 0.13 g of imidazolium salt 4 obtained in Example 7 and 1.00 g of polyglycidyl methacrylate (Mn: 138,000, Mw / Mn: 1.49) were weighed and weighed. 21. Mixed solvent adjusted to have a ratio of cyclohexanone / acetonitrile: 5/2.
It was dissolved in 7 g. After spin coating the above solution on a silicon wafer to a film thickness of 1 μm, the entire surface was irradiated with UV using a high pressure mercury lamp and further heated on a hot plate at 60 ° C. for 10 minutes. Then, it was immersed in THF at room temperature for 3 minutes, and the residual film thickness on the silicon wafer was measured.

The results of Example 8 are shown in Table 3. The residual film rate in the table is defined as the film thickness after development × 100 / the film thickness after spin coating (1 μm).

[0055]

[Table 3]

Since the residual film rate increases with the increase of the UV irradiation amount, the imidazolium salt 4 is exposed to the UV irradiation.
Generated a base and promoted crosslinking of polyglycidyl methacrylate by heating at 60 ° C./10 minutes.

(Example 9) As an epoxy resin, a bisphenol A type epoxy resin (produced by Yuka Shell Epoxy Co., Ltd., trade name Epicoat 828, epoxy equivalent 184)
50 g was dissolved in methyl ethyl ketone in a weight ratio to prepare a solution having a solid content of 40% by weight, which was used. As polythiol, pentaerythrithiol (SH equivalent 50) 1
3.5 g was used. As the imidazolium salt, 2.0 g of the imidazolium salt 2 of Example 2 was used. As the silane coupling agent, 1.5 g of an epoxysilane compound (manufactured by Nippon Unicar Co., Ltd., trade name A187) was used.

As the phenoxy resin, 50 g of bisphenol A, F copolymer type phenoxy resin (average molecular weight 20,000) was prepared from bisphenol A, bisphenol F (1/1) and epichlorohydrin by a general method. Was dissolved in methyl ethyl ketone in a weight ratio to prepare a solution having a solid content of 40% by weight, which was used. As the conductive particles, on the surface of particles having polystyrene as a nucleus,
A nickel layer having a thickness of 0.2 μm is provided, a metal having a thickness of 0.02 μm is provided outside the nickel layer, and an average particle size is 10
Conductive particles having a μm and a specific gravity of 2.0 were prepared and used.

A solution containing the above components except for the conductive particles (50 g of solid epoxy resin, 13.5% polythiol)
g, 2.0 g of imidazolium salt 2, 1.5 g of epoxysilane compound, 50 g of phenoxy resin), 3% by volume of conductive particles are mixed and dispersed, and coated on a fluororesin film having a thickness of 80 μm using a coating device, A film made of the circuit-connecting composition having a thickness of 25 μm was formed on the fluororesin film by drying with hot air at 70 ° C. for 10 minutes.

A line width of 50 μm, a pitch of 100 μm, and a thickness of 1 were obtained using the film adhesive obtained by the above-mentioned manufacturing method.
Flexible circuit board (FPC) having 500 8 μm copper circuits and 0.2 μm indium oxide (ITO)
Glass with a thin layer (thickness 1.1 mm, surface resistance 2
0 Ω / □) was heated and pressed at 170 ° C. and 4 MPa for 60 seconds and connected over a width of 2 mm. At this time, the adhesive surface of the film-like circuit connecting material was preliminarily heated and pressed at 70 ° C. and 0.5 MPa for 5 seconds to temporarily connect to the ITO glass, and then the fluororesin film was peeled off to form the circuit connecting composition. 3.0 J / c by using an ultraviolet irradiation device (manufactured by Ushio Inc.) having a high pressure mercury lamp on the film surface.
It was irradiated with m ² of ultraviolet rays. Then, the other adherend was connected to FPC to obtain a connected body. When the resistance value between the adjacent circuits of this connection body was measured, the resistance value between the adjacent circuits was 15
The average of 0 points (x + 3σ; σ is standard deviation) was 2.7Ω, indicating good connection characteristics.

Also, the adhesive strength of this connector is determined by JIS-Z.
According to 0237, it was measured by the 90 degree peeling method and evaluated. Here, the measuring device of the adhesive strength is Tensilon UTM-4 (Peeling speed 50 mm / mi manufactured by Toyo Baldwin Co., Ltd.
n, 25 ° C.) was used. The adhesive strength of the connector obtained as described above was 600 N / m, showing a sufficient adhesive strength.

(Example 10) 0.672 g of hexamethylene diisocyanate (manufactured by Kanto Chemical Co., Inc.) as an isocyanate resin, and 1.00 g of polytetrahydrofuran (manufactured by BASF Japan, trade name polytetrahydrofuran 250) as a resin having a hydroxyl group. A uniform varnish consisting of 0.016 g of the imidazolium salt 1 of Example 1 was prepared. This was sampled in a sample pan of DSC to be 3 mg, and light irradiation was performed for 10 minutes,
DSC was measured (temperature was constant at 40 ° C). For light irradiation, spot cure manufactured by USHIO INC. Was used (3
65 nm, 53 mW / cm ² ). As a result, 92.4J /
Exothermic heat was obtained by the reaction between the isocyanate compound (g) and the compound having a hydroxyl group, and it was confirmed that the reaction was caused by light irradiation.

According to the present invention, (a) an epoxy resin and an imidazolium salt compound are produced at a low temperature by performing light irradiation,
(B) Epoxy resin, imidazolium salt compound, compound having two or more functional groups reactive with epoxy resin in the molecule, (c) Compound having two or more isocyanate groups in the molecule, imidazolium salt A curable composition capable of low-temperature curing of a compound or a compound having two or more hydroxyl groups in the molecule can be provided.

[Brief description of drawings]

FIG. 1 ¹ H-NMR spectrum diagram of imidazolium salt 1 (solvent: CD ₃ CN, standard substance: TMS, * in the figure is an impurity)

FIG. 2 ¹ H-NMR spectrum diagram of imidazolium salt 2 (solvent: CD ₃ CN, standard substance: TMS, * in the figure is an impurity)

FIG. 3 is a ¹ H-NMR spectrum diagram of imidazolium salt 3 (solvent: CDCl ₃ , standard substance: TMS, * in the figure is an impurity).

FIG. 4 is a ¹ H-NMR spectrum diagram of imidazolium salt 4 (solvent: D ₂ O).

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 2H025 AB14 AB15 AB16 AB17 AB20                       AC01 AD01 BE00 CC20                 4J034 BA02 BA08 CA04 CA05 CB03                       CB04 CC01 DA01 DB04 HA01                       HA02 HA07 HC01 HC12 HC13                       HC52 HC61 KA01 KD11 KE02                       RA19 SA02                 4J036 AA01 AC01 AC02 AC12 AC13                       AC14 AC15 AC21 AD01 AD03                       AD08 AD21 DB05 DB14 DC03                       DC04 DC10 DD02 FA12 GA29                       JA09 KA01

Claims (6)

[Claims] 1. An imidazolium salt compound represented by the general formula (1) or (2), which generates a base upon irradiation with light of 150 to 750 nm. [Chemical 1] (In the formula, R ₁ , R ₂ , R ₃ and R ₄ are independently hydrogen and carbon number 1
~ 8 alkyl group, C1-8 alkoxy group, C1-8 alkylidene group, C4-8 cycloalkyl group, C4-8 cycloalkenyl group, C1
To C6 phenoxyalkyl group, C1 to C6 phenylalkyl group, C1 to C6 cyanoalkyl group, C1 to C6 hydroxyalkyl group, phenyl group, electron donating group and / or electron withdrawing property A phenyl group substituted with a group, a benzyl group, a benzyl group substituted with an electron-donating group and / or an electron-withdrawing group, a nitro group, a cyano group, a mercapto group, a thiomethyl group, fluorine, bromine, chlorine, or iodine. Ar ₁ is an aromatic group represented by the following formulas (I) to (XIV): In the formula, R _{5 to} R ₂₈ are independently hydrogen, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkylthio group having 1 to 8 carbon atoms, an alkylidene group having 1 to 8 carbon atoms, and carbon. Cycloalkyl group having 4 to 8 carbon atoms, cycloalkenyl group having 4 to 8 carbon atoms, amino group, alkylamino group having 1 to 6 carbon atoms, dialkylamino group having 1 to 3 carbon atoms, morpholino group, mercapto group, hydroxyl group, Hydroxyalkyl group having 1 to 6 carbon atoms, halogen such as fluorine, chlorine and bromine, carbon number
1-6 ester group, carbonyl group having 1-6 carbon atoms, aldehyde group, cyano group, trifluoromethyl group, cyano group, nitro group, phenyl group, electron-donating group and / or electron-withdrawing group substituted A benzyl group substituted with a phenyl group, an electron-donating group and / or an electron-withdrawing group. Further, in the formula, A to F represent any of carbon, nitrogen, oxygen and sulfur atoms. Ar ₂ is represented by the following formulas (XV) to (XXII
Which is an aromatic group represented by I): R _{29 to} R ₃₆ are independently hydrogen, an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkylthio group having 1 to 8 carbon atoms, an alkylidene group having 1 to 8 carbon atoms, and 4 carbon atoms. ~ 8 cycloalkyl group, C4-8 cycloalkenyl group, amino group, C1-6 alkylamino group, C1-3 dialkylamino group, morpholino group, mercapto group, hydroxyl group, carbon number 1 to 6 hydroxyalkyl group, halogen such as fluorine, chlorine and bromine, ester group having 1 to 6 carbon atoms, carbonyl group having 1 to 6 carbon atoms, aldehyde group, cyano group, trifluoromethyl group, cyano group, nitro A phenyl group, a phenyl group, a phenyl group substituted with an electron-donating group and / or an electron-withdrawing group, and a benzyl group substituted with an electron-donating group and / or an electron-withdrawing group. Further, in the formula, A to D are independently any of carbon, nitrogen, oxygen and sulfur atoms, and they are carbon, nitrogen and carbon number 1
You may combine with the alkyl group of -6, oxygen, and sulfur. X- is a dialkyldithiocarbamic acid having 1 to 6 carbon atoms, thiocyanate, or boric acid represented by the following formula (XXIV). [Chemical 4] R _{37 to} R ₄₀ are independently hydrogen, fluorine, and 1 to 6 carbon atoms.
Is an alkyl group, a phenyl group, a fluorophenyl group in which at least one of fluorine is substituted, or an imidazole group. 2. A curable composition comprising at least an epoxy resin and the imidazolium salt compound according to claim 1. 3. A curable composition comprising an epoxy resin, the imidazolium salt compound according to claim 1, and a compound having two or more functional groups reactive with the epoxy resin in the molecule. 4. The curable composition according to claim 3, wherein the functional group reactive with the epoxy resin is a carboxyl group, a mercapto group, a phenolic hydroxyl group, a primary or secondary aromatic amino group. 5. A curable composition containing a compound having two or more isocyanate groups in the molecule, an imidazolium salt compound, and a compound having two or more hydroxyl groups in the molecule. 6. A cured product is obtained by curing the curable composition according to any one of claims 2 to 5 by irradiating only light, or simultaneously performing irradiation with light and heating or after irradiation with light. Curing method.