TWI573823B - Cationic polymerization initiator, curing agent composition and epoxy resin composition - Google Patents

Description

Cationic polymerization initiator, hardener composition and epoxy resin composition

The present invention relates to a cationic polymerization initiator, a hardener composition containing the cationic polymerization initiator, and an epoxy resin composition containing the same.

Conventionally, as a curing agent for an epoxy resin, a cationic polymerization initiator such as a phosphonium salt compound is known (for example, Patent Document 1).

[Practical Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2011-168574

The inventors of the present invention conducted research on an epoxy resin composition containing a cationic polymerization initiator as described in Patent Document 1 as a curing agent. After the discussion, it was found that although the hardenability was good, the storage stability was poor.

Accordingly, an object of the present invention is to provide a cationic polymerization initiator which, when used as a hardener component of an epoxy resin composition, can improve the storage stability of the epoxy resin composition without impairing the hardenability of the epoxy resin composition.

The inventors of the present invention actively reviewed the above objectives. As a result, it has been found that when a cationic polymerization initiator having a specific structure of an onium salt compound is used as a hardener component of the epoxy resin composition, the hardenability of the epoxy resin composition is not impaired, and storage stability is excellent, thereby completing this invention.

That is, the present invention provides the following (I) to (V).

(I) A cationic polymerization initiator which is an onium salt compound represented by the formula (1) described later.

(II) A curing agent composition comprising the cationic polymerization initiator according to the above (I) and a stabilizer of the compound represented by the formula (6) below.

(III) The hardener composition according to the above (II), wherein the stabilizer content is 0.001 to 20% by mass based on the cationic polymerization initiator.

(IV) An epoxy resin composition comprising an epoxy resin and a hardener component, wherein the hardener component is a cationic polymerization initiator of the above (I) or a hardener of the above (II) or (III) Things.

(V) The epoxy resin composition according to the above (IV), wherein the hardener component is 0.1 to 20 in terms of 100 parts by mass of the epoxy resin Quantities.

According to the present invention, it is possible to provide a cationic polymerization initiator which, when used as a hardener component of an epoxy resin composition, can improve the storage stability of the epoxy resin composition without impairing the hardenability of the epoxy resin composition.

<Cationic polymerization initiator>

The cationic polymerization initiator of the present invention is a cationic polymerization initiator of the onium salt compound represented by the following formula (1), and an epoxy resin composition using the cationic polymerization initiator of the present invention together with an epoxy resin. It has excellent storage stability. At this time, the hardenability is also not lost.

The reason may be that R ² (alkyl group having 1 to 6 carbon atoms) or R ³ (hydrogen atom or alkyl group having 1 to 6 carbon atoms) in the following formula (1) causes steric hindrance, making it difficult to form an epoxy resin. Close to the sulfur cations, thus improving storage stability.

Hereinafter, the cationic polymerization initiator of the present invention will be described in detail.

The cationic polymerization initiator of the present invention is a cationic polymerization initiator which is an onium salt compound represented by the following formula (1).

In the formula (1), R ¹ represents a hydroxyl group or a group represented by any one of the following formulas (2) to (5), R ² represents an alkyl group having 1 to 6 carbon atoms, and R ³ represents a hydrogen atom or a carbon number. An alkyl group of 1 to 6, R ⁴ represents an alkyl group having 1 to 6 carbon atoms, and R ⁵ represents an unsaturated hydrocarbon group which may have a substituent.

In the formulae (2) to (5), R ⁶ each independently represents an aromatic or aliphatic hydrocarbon group which may have a substituent which may contain a hetero atom. Further, examples of the hetero atom include an oxygen atom, a sulfur atom, and a nitrogen atom.

From the viewpoint of adjusting the curability of the epoxy resin composition, R ⁶ in the formulae (2) to (5) may be selected from various substituents, and is not particularly limited, and may have a hetero atom as shown by R ⁶ . Examples of the aromatic hydrocarbon group of the substituent include an aryl group having 6 to 18 carbon atoms such as a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, a fluorenyl group, and a tosyl group; a benzyl group and a phenyl group; An arylalkyl group such as a styrene group; an arylalkenyl group such as a styryl group or a cinnamyl group; and the like.

Further, the aliphatic hydrocarbon group which may have a substituent which may contain a hetero atom represented by R ^{6 is} exemplified by a saturated or unsaturated chain hydrocarbon group having 1 to 12 carbon atoms such as an alkyl group, an alkenyl group or an alkynyl group. For example, listed as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, tert-butyl, pentyl, isopentyl, neopentyl, third amyl, Hexyl, isohexyl, 2-ethylhexyl, heptyl, octyl, decyl, decyl, undecyl, dodecyl, vinyl, allyl, isopropenyl, -CH=CH- ( CH ₂ ) ₈ -yl, ethynyl and the like.

In the above, the base represented by R ^{6 is} preferably an aromatic hydrocarbon group which may have a substituent which may contain a hetero atom, and more preferably has a carbon number of 6 to 18, for the reason that the epoxy resin composition is excellent in curability. The aryl group is more preferably p-toluenesulfonyl.

The group represented by R ¹ in the formula (1) is not particularly limited as long as it is a hydroxyl group or a group represented by any one of the formulas (2) to (5), but is based on the curability of the epoxy resin composition. The reason for the superiority is preferably a hydroxyl group or a group represented by the formula (4).

The alkyl group having 1 to 6 carbon atoms represented by R ² in the formula (1) is exemplified by, for example, a methyl group, an ethyl group, a n-propyl group, a n-butyl group, a n-pentyl group, a n-hexyl group or the like. It is a methyl group or an ethyl group.

The alkyl group having 1 to 6 carbon atoms represented by R ³ in the formula (1) is exemplified by, for example, a methyl group, an ethyl group, a n-propyl group, a n-butyl group, a n-pentyl group, a n-hexyl group, etc., preferably A. Base, ethyl.

The group represented by R ³ in the formula (1) is not particularly limited as long as it is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, but is preferably a hydrogen atom from the viewpoint of easy availability.

Here, the group represented by R ¹ to R ³ corresponds to a substituent substituted with a hydrogen atom of a benzene ring in the formula (1), and the position thereof is not particularly limited, but is relative to the sulfur bonded to the benzene ring. The atom, the group represented by R ² and R ³ , is preferably located in the ortho position. Accordingly, for an epoxy resin close to a sulfur cation, it will be more steric hindrance, and the storage stability is more excellent.

Further, the position of the group represented by R ¹ is not particularly limited, and is exemplified by, for example, a position opposite to a sulfur atom bonded to a benzene ring.

The alkyl group having 1 to 6 carbon atoms represented by R ⁴ in the formula (1) is exemplified by, for example, a methyl group, an ethyl group, a n-propyl group, a n-butyl group, a n-pentyl group, a n-hexyl group or the like. It is a methyl group or an ethyl group.

The unsaturated hydrocarbon group which may have a substituent represented by R ⁵ in the formula (1) is, for example, an aromatic hydrocarbon group which may have a substituent, and specific examples thereof include a phenyl group, a naphthyl group, a biphenyl group, and an anthracene. An aryl group having 6 to 18 carbon atoms such as a thiol group, a fluorenyl group or a tosyl group; an arylalkyl group such as a benzyl group or a phenethyl group; an arylalkenyl group such as a styryl group or a cinnamyl group; Wait.

In the case where the epoxy resin composition is excellent in the curability of the epoxy resin composition, the group represented by R ^{5 is} preferably an aryl group or an arylalkenyl group having 6 to 18 carbon atoms, more preferably a naphthyl group or a styrene group. base.

(Method for producing cationic polymerization initiator)

The method for producing the onium salt compound represented by the formula (1) of the cationic polymerization initiator of the present invention is not particularly limited.

For example, the compound represented by the following formula (a1) and the compound represented by the following formula (a2) are first introduced into methanol of an organic solvent at a room temperature of 1.0:1.0 molar ratio at room temperature. The mixture was allowed to react for about 24 hours, and a chloride intermediate represented by the following formula (a3) was obtained.

Then, the obtained chloride intermediate and sodium salt of ruthenium (pentafluorophenyl)borate are mixed in an aqueous solvent at room temperature to form a molar ratio of 1.0:1.0 to 1.0:1.1. In the hour, the onium salt compound represented by the above formula (1) is obtained.

Further, ~ (a3) of, R ¹ ~ R ⁵ and (1) R ¹ ~ R ⁵ same meaning as the following formula (a1) above formula, description thereof is omitted.

As described above, specific examples of the onium salt compound represented by the formula (1) include the onium salt compound represented by the following formula (1A).

<hardener composition>

The hardener composition of the present invention contains the above-described cationic polymerization initiator of the present invention and a stabilizer composition of a stabilizer of the compound represented by the following formula (6).

As described above, the epoxy resin composition used in the cationic polymerization initiator of the present invention together with the epoxy resin is excellent in storage stability, but by further containing the stabilizer, storage stability is further improved.

The reason for this is that, for example, when the stabilizer is a compound represented by the following formula (6A), the methyl group of the electron-donating group is introduced into the ortho position to increase the nucleophilicity of the sulfide, thereby improving storage stability.

Further, it can be considered that, for example, when the stabilizer is expressed by the following formula (6B) In the case of the compound, in addition to the nucleophilicity of the sulfide, the structure in which the carbonyl oxygen of the carboxyl group is coordinated to the onium salt can be obtained, and thus the storage stability can be improved by such an effect.

Hereinafter, the stabilizer contained in the hardener composition of the present invention will be described first.

(stabilizer)

The stabilizer contained in the hardener composition of the present invention is a compound represented by the following formula (6).

In the formula (6), R ⁷ represents a hydroxyl group, a carboxyl group or a group represented by the following formula (7), R ⁸ represents an alkyl group having 1 to 6 carbon atoms, and R ⁹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. . Here, when R ⁹ represents a hydrogen atom, R ⁷ represents a carboxyl group.

[6] R ¹⁰ O- (7)

In the formula (7), R ¹⁰ represents an alkyl group having 1 to 6 carbon atoms or an aromatic hydrocarbon group which may have a substituent.

The alkyl group having 1 to 6 carbon atoms represented by R ¹⁰ in the formula (7) is exemplified by, for example, a methyl group, an ethyl group, a n-propyl group, a n-butyl group, a n-pentyl group, a n-hexyl group or the like. Methyl, ethyl.

Further, the aromatic hydrocarbon group which may have a substituent represented by R ¹⁰ in the formula (7) is exemplified by, for example, a phenyl group, a naphthyl group, a biphenyl group, a fluorenyl group, a fluorenyl group, a tosyl group. An aryl group having 6 to 18 carbon atoms; an arylalkyl group such as a benzyl group or a phenethyl group; an arylalkenyl group such as a styryl group or a cinnamyl group; and the like.

The group represented by R ⁷ in the formula (6) is preferably a hydroxyl group or a carboxyl group, for the reason that the storage stability of the epoxy resin composition is more excellent.

The alkyl group having 1 to 6 carbon atoms represented by R ⁸ in the formula (6) is exemplified by, for example, a methyl group, an ethyl group, a n-propyl group, a n-butyl group, a n-pentyl group, a n-hexyl group or the like. It is a methyl group or an ethyl group.

The alkyl group having 1 to 6 carbon atoms represented by R ⁹ in the formula (6) is exemplified by a methyl group, an ethyl group, a n-propyl group, a n-butyl group, a n-pentyl group, a n-hexyl group, or the like. It is preferably methyl or ethyl.

The group represented by R ⁹ in the formula (6) is not particularly limited as long as it is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, but it is more excellent in storage stability of the epoxy resin composition. It is preferably an alkyl group having 1 to 6 carbon atoms.

As described above, specific examples of the compound represented by the formula (6) include compounds represented by the following formula (6A) or (6B).

The content of the stabilizer is preferably from 0.001 to 20% by mass, more preferably from 0.01 to 10% by mass, still more preferably from 0.05 to 10% by mass, based on the cationic polymerization initiator of the present invention.

When the stabilizer content is in this range, the storage stability can be more excellent in the epoxy resin composition using the hardener composition of the present invention.

The method for producing the curing agent composition of the present invention is not particularly limited, and examples thereof include a method in which the cationic polymerization initiator and the stabilizer of the present invention are sufficiently kneaded and uniformly dispersed under reduced pressure or an inert gas atmosphere.

Further, the method for producing the epoxy resin composition of the present invention described later may also serve as a method for producing the curing agent composition of the present invention.

<Epoxy Resin Composition>

Next, the epoxy resin composition of the present invention will be described. The epoxy resin composition of the present invention contains an epoxy resin composition of an epoxy resin and a hardener component, and the hardener component is the cationic polymerization of the present invention described above. A starter or a hardener composition of the present invention.

Since the epoxy resin composition of the present invention contains the cationic polymerization initiator of the present invention or the hardener composition of the present invention as a hardener component of the epoxy resin, the storage stability can be excellent without loss of curability.

In this case, the content of the curing agent component is preferably from 0.1 to 20 parts by mass, more preferably from 0.5 to 10 parts by mass, per 100 parts by mass of the epoxy resin. When the content of the above-mentioned hardener component is within this range, the epoxy resin composition of the present invention is more excellent in storage stability, and a cured product having a high glass transition point can be obtained.

(epoxy resin)

The epoxy resin contained in the epoxy resin composition of the present invention is not particularly limited as long as it has two or more epoxy groups, and can be used, for example, as a bisphenol A type epoxy resin or a bisphenol F. Type epoxy resin, dicyclopentadiene type epoxy resin, diaminodiphenylmethane type epoxy resin, aminophenol type epoxy resin, naphthalene type epoxy resin, phenol novolak type epoxy resin, joint Benzene type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated bisphenol type epoxy resin, polyalkylene glycol type epoxy resin, alicyclic epoxy resin, etc. One type may be used alone or two or more types may be used at the same time.

Commercially available products can be used for these epoxy resins. For example, the bisphenol A type epoxy resin is exemplified by, for example, Epikote 828 (manufactured by JER Co., Ltd.) and EP4100E (manufactured by Adeka Co., Ltd.), and examples of the polyalkylene glycol type epoxy resin are, for example, EP4000S and EP4010S (all are ADEKA Corporation). system Illustratively, the alicyclic epoxy resin is exemplified by CELLOXIDE 2021P (manufactured by Daicel Chemical Co., Ltd.).

(additive)

The epoxy resin composition of the present invention may contain, for example, a filler, a reaction retarder, an anti-aging agent, an antioxidant, a pigment (dye), a plasticizer, a shake imparting agent, etc., as needed within the scope of the object of the present invention. Various additives such as a UV absorber, a flame retardant, a solvent, a surfactant (including a leveling agent), a dispersing agent, a dehydrating agent, an adhesion-imparting agent, and an antistatic agent are also not particularly limited.

The method for producing the epoxy resin composition of the present invention is not particularly limited, and examples thereof include a method of using an apparatus such as a ball mill under a reduced pressure or an inert gas atmosphere, and the epoxy resin, the hardener component, and the like. The additives to be used are thoroughly kneaded and uniformly dispersed.

Further, the method for producing an epoxy resin composition of the present invention may also serve as a method for producing the above-described hardener composition of the present invention.

Since the epoxy resin composition of the present invention is excellent in storage stability, it can be used as a one-liquid type. When the epoxy resin composition of the present invention is a one-liquid type, the epoxy resin composition of the present invention can be placed in a container and sealed, and then stored at room temperature or lower (for example, -20 to 25 ° C).

Further, since the epoxy resin composition of the present invention is excellent in storage stability, thickening can be suppressed even under a relatively high temperature condition, and specifically, it can be stored, for example, at about 30 to 75 °C.

The epoxy resin composition of the present invention is short under heating conditions After heating, it can be hardened. The heating temperature is preferably from 80 to 250 ° C, and is preferably from 80 to 200 ° C from the viewpoint of shortening the hardening time in production.

The adherend to which the epoxy resin composition of the present invention can be used is exemplified by, for example, a glass material, a plastic material, a metal, an organic-inorganic composite material, or the like.

The use of the epoxy resin composition of the present invention is not particularly limited, and examples thereof include a sealing material, a laminate, an adhesive, a sealing material, and a coating material. Further, since the epoxy resin composition of the present invention can be cured at a low temperature for a short period of time, the internal stress generated during curing can be reduced, and therefore, it can be suitably used, for example, in the field of electronic materials such as an anisotropic conductive film.

Example

Hereinafter, the present invention will be specifically described by way of examples. However, the invention is not limited thereto.

<Preparation of cationic polymerization initiator>

(Modulation of cationic polymerization initiator 1)

First, 176.64 g of 1-(chloromethyl)naphthalene and 154.23 g of 4-(methylthio)-m-cresol were reacted in methanol at room temperature for 24 hours to obtain a chloride intermediate. Then, 100 g of the obtained chloride intermediate and 2121 g of an aqueous solution of sodium salt of cerium (pentafluorophenyl)borate (solid content: 10%) were mixed at room temperature for 24 hours to obtain a compound. The obtained compound was analyzed (analyzed by ¹ H-NMR and HPLC, and the same applies hereinafter), and the sulfonium salt compound represented by the above formula (1A) was confirmed. The onium salt compound represented by the formula (1A) thus obtained was used as the cationic polymerization initiator 1.

(Modulation of cationic polymerization initiator 2)

The same preparation as the cationic polymerization initiator 1 except that 78.2 g of sodium hexafluoroantimonate (Na[SbF ₆ ]) and 700 g of water were used instead of the sodium salt solution of cerium (pentafluorophenyl)borate (solid content: 10%). , obtaining a compound. The result of the analysis of the obtained compound was confirmed to be an onium salt compound represented by the following formula (X1). The onium salt compound represented by the formula (X1) thus obtained is used as the cationic polymerization initiator 2.

(Modulation of cationic polymerization initiator 3)

First, 176.64 g of 1-(chloromethyl)naphthalene and 140.2 g of 4-(methylthio)phenol were reacted in methanol at room temperature for 24 hours to obtain a chloride intermediate. Then, 100 g of the obtained chloride intermediate and 2258 g of an aqueous solution of sodium salt of cerium (pentafluorophenyl)borate (solid content: 10%) were mixed at room temperature for 24 hours to obtain a compound. The result of analysis of the obtained compound, It was confirmed to be an onium salt compound represented by the following formula (X2). The onium salt compound represented by the formula (X2) thus obtained is used as the cationic polymerization initiator 3.

(Modulation of cationic polymerization initiator 4)

According to the method described in International Publication No. 2010/064648, an onium salt compound represented by the following formula (X3) is obtained. The obtained onium salt compound represented by the formula (X3) was used as the cationic polymerization initiator 4.

<Modulation of epoxy resin composition>

The components were blended so as to have the composition (unit: parts by mass) shown in Table 1 below, and then uniformly mixed using a blender (Conditioning Mixer MX-20, manufactured by THINKY Co., Ltd.), and also used as a curing hardener in some cases. The composition is used to prepare an epoxy resin composition.

<evaluation>

For each of the prepared epoxy resin compositions, the gelation time and the viscosity increase rate were measured by the following methods, respectively, thereby evaluating the hardenability and storage stability. The results are shown in Table 1 below.

(gelling time)

For each of the prepared epoxy resin compositions, the gelation time (unit: second) at 150 ° C was measured using an Yasuda gel time tester (manufactured by Yasuda Seiki Co., Ltd., No. 153 gel time tester).

In addition, the Yasuda gel time tester is a device that rotates the rotor in an oil bath and a test tube containing the sample. After the gelation is performed and a certain torque is applied, the rotor is dropped using a magnetic coupling mechanism. And stop the timer.

(viscosity increase rate)

Put the prepared epoxy resin composition into an oven at 40 ° C or 60 ° C In the middle, the viscosity at the initial and after 2 hours was measured, and the increase rate was taken as the viscosity increase rate. The initial viscosity was measured using an E-type viscometer VISCONIC EHD type (manufactured by Toki Sangyo Co., Ltd.). Next, the obtained initial viscosity and the viscosity value after 2 hours were substituted into the following formula to calculate the viscosity increase rate.

(viscosity increase rate) = (viscosity after 2 hours) / (initial viscosity)

The details of each component shown in the above Table 1 are as follows.

̇Epoxy resin 1: bisphenol A type epoxy resin (EP4100E, manufactured by ADEKA)

Ruthenium cation polymerization initiator 1: bismuth salt represented by the above formula (1A) Compound

Ruthenium cation polymerization initiator 2: an onium salt compound represented by the above formula (X1)

Ruthenium cation polymerization initiator 3: an onium salt compound represented by the above formula (X2)

Ruthenium cation polymerization initiator 4: an onium salt compound represented by the above formula (X3)

̇Resin 1: A compound represented by formula (6A) (manufactured by Tokyo Chemical Industry Co., Ltd.)

̇ stabilizer 2: a compound represented by formula (6B) (manufactured by Tokyo Chemical Industry Co., Ltd.)

As a result of the above-described first table, it was found that Examples 1 to 5 using the cationic polymerization initiator 1 were lower in viscosity increase rate and superior in storage stability than Comparative Examples 2 or 4 in which these were not used.

Further, as a result, in Comparative Example 3 using the stabilizer 1, the viscosity increase rate was low at 40 ° C, but the viscosity increase rate was high at 60 ° C. On the other hand, in Examples 1 to 5, the viscosity increase rate at 60 ° C was also low, and the storage stability was excellent.

Further, with respect to Comparative Examples 2 to 4, the gelation times of Examples 1 to 5 were the same, and the curing property was not deteriorated and was good.

On the other hand, in Comparative Example 1 using the cationic polymerization initiator 2, although the storage stability was good, the gelation time was longer than that of Examples 1 to 5, and the hardenability was poor.

Claims (5)

A cationic polymerization initiator which is an onium salt compound represented by the following formula (1), (In the formula (1), R ¹ represents a hydroxyl group or a group represented by any one of the following formulas (2) to (5), R ² represents an alkyl group having 1 to 6 carbon atoms, and R ³ represents a hydrogen atom or a carbon number. An alkyl group of 1 to 6, R ⁴ represents an alkyl group having 1 to 6 carbon atoms, and R ⁵ represents an unsaturated hydrocarbon group which may have a substituent), (In the formulae (2) to (5), R ⁶ each independently represents an aromatic or aliphatic hydrocarbon group which may have a substituent which may contain a hetero atom). A hardener composition containing the cationic polymerization initiator of claim 1 and a stabilizer of a compound represented by the following formula (6), (In the formula (6), R ⁷ represents a hydroxyl group, a carboxyl group or a group represented by the following formula (7), R ⁸ represents an alkyl group having 1 to 6 carbon atoms, and R ⁹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. However, when R ⁹ represents a hydrogen atom, R ⁷ represents a carboxyl group, and R ⁴ O- (7) (in the formula (7), R ¹⁰ represents an alkyl group having 1 to 6 carbon atoms or may have a substituent. Aromatic hydrocarbon group). The hardener composition of claim 2, wherein the stabilizer is contained in an amount of from 0.001 to 20% by mass based on the cationic polymerization initiator. An epoxy resin composition comprising an epoxy resin and a hardener component, wherein the hardener component is the cationic polymerization initiator of claim 1 or the hardener composition of claim 2 or 3. The epoxy resin composition of claim 4, wherein the foregoing 100 parts by mass of the epoxy resin, and the content of the hardener component is 0.1 to 20 parts by mass.