WO2020202777A1

WO2020202777A1 - Epoxy curing compound and epoxy resin composition

Info

Publication number: WO2020202777A1
Application number: PCT/JP2020/004279
Authority: WO
Inventors: 中　建介; 松川公洋; 川崎徳明; 池下真二; 竹綱啓尚
Original assignee: 堺化学工業株式会社
Priority date: 2019-03-29
Filing date: 2020-02-05
Publication date: 2020-10-08
Also published as: TW202102568A; JP2020164631A

Abstract

[Problem] To provide an epoxy curing compound that makes it possible to obtain an epoxy resin composition having high heat resistance, flexibility, water resistance, and transparency. [Solution] An epoxy curing compound characterized by being represented by general formula (1) or general formula (2). (In general formula (1), A is an optionally substituted C2-50 linear or branched hydrocarbon group optionally having a functional group that contains a hetero atom in the main chain and/or a side chain. A and S are connected without the intervention of an atom. a represents an integer of 2-6.) (In general formula (2), Rs is a hydrogen or a methyl group. R has a C2-28 linear or branched or cyclic structure optionally having a functional group that contains a hetero atom. R' represents at least one selected from hydrogen atoms, C1-8 alkyl groups, thiol groups, and functional groups represented by general formula (5). b is an integer, including 0, and c is an integer from 1 to 6, such that b + c = 2-6.) In general formulas (1) and (2), Rx are the same or different and represent hydrogen or a structure selected from the group consisting of [chemical formula 3] and [chemical formula 4] (in general formulas (3) and (4), R₁-R₁₀ are the same or different and represent a hydrogen atom or a linear or branched C1-4 alkyl group. The wavy line represents a bonding site.), and one or more Rx is a structure represented by general formula (3) or (4). (In general formula (5), R₁₁ and R₁₂ are different; R₁₁ represents a thiol group or a methyl group, and R₁₂ represents a hydrogen atom or a thiol group. The wavy line represents a bonding site.)

Description

Epoxy curing compound and epoxy resin composition

The present invention relates to an epoxy curing compound that can be used as an epoxy curing agent, a method for producing the same, and an epoxy resin composition containing the same.

In recent years, the output of optical semiconductor devices has been increasing, and they have water resistance and transparency while maintaining high heat resistance and flexibility, and are durable under high temperature and high temperature and high humidity of optical semiconductor devices. There is a demand for a cured product having properties. An epoxy compound is often used as a raw material for a cured product, and in order to cure the epoxy compound, a compound called an acid anhydride obtained by dehydrating and condensing a polyvalent carboxylic acid compound is used as a curing agent. For example, a liquid epoxy resin composition has been proposed as a sealing agent for forming a sealing material having high heat resistance, and norbornane-2,3-dicarboxylic acid anhydride or a derivative thereof is used as a curing agent. (Patent Document 1 etc.).

Patent Document 2 describes a resin composition composed of an epoxy resin, a thiol, and a curing agent (acid anhydride, amine-based curing agent, etc.), and tetrahydrophthalic anhydride is described as an acid anhydride.

Patent Document 3 describes an epoxy resin composition containing a compound having two or more epoxy groups, an acid anhydride, a branched polyfunctional thiol compound, and a curing accelerator, and the acid anhydride is a tri. Alkyltetrahydrophthalic anhydrides have been described.

As described above, the epoxy resin composition is used in various applications other than the sealing agent, but one having flexibility and durability at a high temperature is not known, and further. There was still room for improvement in transparency and colorability. Therefore, if these performances are improved, it is expected to be applied in many applications.

Japanese Unexamined Patent Publication No. 2003-2951 Japanese Patent No. 5224734 JP-A-2017-82124

An object of the present invention is to provide an epoxy curing compound capable of solving the above problems and obtaining an epoxy resin composition having high transparency while maintaining high heat resistance and flexibility.

The present invention is an epoxy curing compound characterized by being represented by the following general formula (1) or general formula (2).

(In the general formula (1), A may have a substituent and may have a functional group containing a hetero atom in the main chain and / or the side chain, and has 2 to 50 carbon atoms. A and S are connected without intervening atoms. A represents an integer of 2 to 6).

(In the general formula (2), Rs is a hydrogen or a methyl group. R has a linear or branched or cyclic structure having 2 to 28 carbon atoms which may have a functional group containing a hetero atom. R'represents at least one selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a thiol group, and a functional group represented by the following general formula (5). B and c are b + c. = 2 to 6, b is an integer including 0, and c is an integer of 1 to 6.) In the general formulas (1) and (2), Rx is the same or different, hydrogen.

as well as

(In the general formulas (3) and (4), R ₁ to R ₁₀ represent hydrogen atoms or linear or branched alkyl groups having 1 to 4 carbon atoms, which are the same or different, and wavy lines indicate binding sites. It is a structure selected from the group consisting of (the same applies hereinafter), and one or more of Rx is a structure represented by the general formula (3) or (4).

(In the general formula (5), R ₁₁ and R ₁₂ are different, R ₁₁ represents a thiol group or a methyl group, and R ₁₂ represents a hydrogen atom or a thiol group.)

In the above general formula (2), R preferably has any of the structures represented by the following general formulas (6) to (10).

(N indicates an integer from 1 to 10.)

The present invention is an epoxy resin composition containing at least an epoxy compound (A) and a curing agent (B), wherein the curing agent (B) is the above-mentioned epoxy curing compound. It is also a thing. The epoxy resin composition may further contain a curing accelerator (C).

The present invention represents an acid anhydride compound represented by the following general formula (11) and / or an acid anhydride compound represented by the following general formula (12) and the following general formula (13) or general formula (14). It is also a method for producing the above-mentioned epoxy curing compound, which comprises a step (1) for forming a sulfide bond by an enthiol reaction with a composition containing the thiol compound to be obtained.

(In the general formulas (11) and (12), R ₁ to R ₁₀ represent hydrogen atoms or linear or branched alkyl groups having 1 to 4 carbon atoms, which are the same or different.)

(In the general formula (13), A may have a substituent and may have a functional group containing a heteroatom in the main chain and / or the side chain, and has 2 to 50 carbon atoms. A and S are connected without intervening atoms. D represents an integer of 2 to 6).

(In the general formula (14), Rs is a hydrogen or methyl group. R has a linear, branched or cyclic structure having 2 to 28 carbon atoms which may have a functional group containing a hetero atom. R ″ indicates at least one selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a thiol group, and a functional group represented by the following general formula (5). E and f are. e + f = 2 to 6, e is an integer including 0, and f is an integer of 1 to 6).

The above step (1) is preferably performed in the presence of the epoxy compound (A). It is more preferable that the above step (1) is carried out in the presence of an acid anhydride compound composed of the general formula (15), the general formula (16) or a mixture thereof.

The epoxy resin composition using the compound of the present invention as a curing agent has high thermal decomposition temperature and bending elasticity, so that it has excellent heat resistance and flexibility, high transparency, and a cured product having a good hue. be able to.

It is a figure which shows the chart of each ¹ H-NMR of PEMP, MHAC-P which is a raw material of Example 1, and the compound obtained by Example 1. FIG. It is a figure which shows the chart of each ^{1 1} H-NMR of the compound obtained by a liquid MH-700, a MHAC-P, an Example 2 and an Example 3 which are raw materials of Examples 2 and 3. It is a figure which shows the chart of each ^{1 1} H-NMR of the compound obtained by the liquid MH-700, MHAC-P which is the raw material of Examples 4 and 5, and the compounds obtained by Example 4 and Example 5.

The compound of the present invention is a compound represented by the following general formula (1) or general formula (2).

The general formulas (1) and (2) have the following structures.

as well as

(In the general formulas (3) and (4), R ₁ to R ₁₀ represent the same or different hydrogen atoms or linear or branched alkyl groups having 1 to 4 carbon atoms.) Selected from the group. One or more of Rx is a structure represented by the general formula (3) or (4).

(In the general formula (5), R ₁₁ and R ₁₂ are different, R ₁₁ represents a thiol group or a methyl group, and R ₁₂ represents a hydrogen atom or a thiol group.) That is, the epoxy curing compound of the present invention. Is a compound having one or more of the above-S-Rx groups in the molecule.

When the acid anhydride represented by the formulas (11) and (12) as a curing agent and the thiol compound are mixed with the epoxy compound and cured, or when the general formula (1) or (2) is used as in the present invention. The performance as an epoxy curing agent is different from the case where the compound is as represented and then mixed with an epoxy compound and cured. The present inventors have found that an epoxy resin composition using a compound represented by the general formula (1) or (2) as a curing agent has high transparency and good flexibility while maintaining high heat resistance and flexibility. The present invention was completed by finding that it has a hue. Such excellent effects can be obtained by increasing the crosslink density with the polyfunctional acid anhydride of the compound represented by the general formula (1) or (2), and as a result, heat resistance. It is presumed that this is because flexibility is imparted by introducing a sulfide bond into the skeleton in addition to maintaining the above.

The epoxy curing agent of the present invention is a compound having a structure represented by the above general formula (1) or (2).

In the following description, the Rx group, which is a structural unit represented by the general formula (3) or the general formula (4), will be described in detail, and then the structure represented by the general formula (1) and the general formula (2). Will be described in detail.

The Rx group includes a structural unit represented by the general formula (3) or the general formula (4) as described above. The structural unit represented by the general formula (3) is a structural unit derived from 5-norbornene-2,3-dicarboxylic acid anhydride or a derivative thereof. The structural unit represented by the general formula (3) is preferably a compound in which 0 to 4 (particularly 0 to 2) of R ₁ to R ₆ are methyl groups, from the viewpoint of heat resistance of the cured product. Methylnorbornene 2,3-dicarboxylic acid anhydride and norbornene 2,3-dicarboxylic acid anhydride are preferable.

In the norbornene skeleton of the structural unit represented by the general formula (3), stereoisomers of exo and end forms are present. In the compound represented by the general formula (3), when the abundance ratio of the exo form increases, it tends to become liquid at room temperature, so that it tends to be easy to handle. Therefore, it is preferable that the constituent unit represented by the general formula (3) contains the exo form as an essential component. More specifically, the abundance ratio of the exo body in the compound represented by the general formula (3) [exo body / (exo body + end body)] is preferably 40% by weight or more, more preferably 50% by weight or more. is there. If the abundance ratio of the exo form is less than 40% by weight, the compound represented by the formula (3) tends to become a solid at room temperature, which may make handling difficult. The method for setting the abundance ratio of the exo form to 40% by weight or more is not particularly limited, but as described in the specific example below, isomerization to the exo form is promoted in the structural unit represented by the formula (3). There is a method of putting it.

The above-mentioned "methylnorbornene 2,3-dicarboxylic acid anhydride" in the present specification is a general term for each isomer having a different bond position of a methyl group on the norbornene ring. Typical examples of methylnorbornene 2,3-dicarboxylic acid anhydride include 5-methylnorbornene 2,3-dicarboxylic acid anhydride.

The chemical structure represented by the general formula (4) is a chemical structure derived from 1,2,3,6-tetrahydrophthalic anhydride or a derivative thereof. Examples of the derivative include various alkyl substitutions. For example, methyltetrahydrophthalic anhydride (4-methyltetrahydrophthalic anhydride, 3-methyltetrahydrophthalic anhydride, etc.) and the like can be mentioned. Examples of commercially available products of such compounds include trade names "HN-2200" and "HN-2000" (all manufactured by Hitachi Chemical Co., Ltd.).

From the viewpoint of performance when used as an epoxy resin curing agent, the chemical structure represented by the general formula (3) has better performance than the chemical structure represented by the general formula (4). It is a more preferable compound.

A in the general formula (1) may have a functional group containing various heteroatoms that does not directly affect the enthiol reaction. The functional group may be present as a side chain or may be present in the main chain. That is, the chemical structure derived from any organic compound having two or more thiol groups can be represented by the general formula (1).

The hydrocarbon represented by A is not particularly limited, and is a hydrocarbon group having 2 to 50 carbon atoms which may have a cyclic group and has a substituent in the main chain or the side chain. There may be. The number of carbon atoms is more preferably 5 or more, and most preferably 14 or more. Further, the number of carbon atoms is more preferably 36 or less, and most preferably 28 or less. Examples of the substituent that may be present in A include an ether group, an ester group, a cyclic hydrocarbon structure, a uryl group, a heterocyclic structure, a sulfide group, an amino group, an amide group, a urethane group, and a ketone group. Can be mentioned. Of these, those having two or more structures may be used. Further, these functional groups may be those existing as side chain functional groups, or may be functional groups forming a part of the main chain.

The cyclic hydrocarbon structure as a functional group in A may be an aromatic group such as a benzene ring or a naphthalene ring, or an alicyclic group such as a cyclohexane ring. The heterocyclic structure may have any structure such as 1,3,5-triazine ring, 1,3,4,6-glycoluryl ring and the like. These cyclic structures may be present in the main chain or in the side chain.

The general formula (2) is a structure derived from the thiol compound represented by the general formula (14). Since the above general formula (2) is also an ester of a mercaptocarboxylic acid and a polyhydric alcohol, the compound of the present invention is obtained by sulfides a part or all of the thiol groups of the compound with a specific acid anhydride compound. Can be obtained.

In the general formula (2), R is a hydrocarbon group having a linear, branched or cyclic structure having 2 to 28 carbon atoms, which may have a functional group containing a hetero atom. Any functional group may be present in R as long as it does not adversely affect the reactivity. The functional group in R in the general formula (14) is not particularly limited, and for example, an ether group, an ester group, a cyclic hydrocarbon structure, a uryl group, a heterocyclic structure, a sulfide group, an amino group, an amide group, and the like. Examples thereof include a urethane group and a ketone group. Of these, those having two or more structures may be used.

The hydrocarbon group in R may be any of an aliphatic hydrocarbon, an aromatic hydrocarbon, and an alicyclic hydrocarbon, and may be a condensed product of a plurality of rings. Further, the aromatic hydrocarbon and the alicyclic hydrocarbon may be present in the main chain or in the side chain.

In the general formula (2), R is particularly preferably any of the functional groups represented by the following general formulas (6) to (10).

(N indicates an integer from 1 to 10.)

In the general formula (2), R'represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a thiol group, and a functional group represented by the following general formula (5).

The general formulas (1) and (2) are structures derived from a thiol compound, and specific examples of the thiol compound from which such a structure is derived include trimethylolpropanthris (3-mercaptopro). Pionate) (TMMP manufactured by SC Organic Chemistry Co., Ltd.), Tris-[(3-mercaptopropionyloxy) -ethyl] -isocyanurate (TMPIC manufactured by SC Organic Chemistry Co., Ltd.), pentaerythritol tetrakis (3-mercaptopropionate) (PEMP manufactured by SC Organic Chemistry Co., Ltd.), Tetraethylene glycol bis (3-mercaptopropionate) (EGMP-4 manufactured by SC Organic Chemical Co., Ltd.), Dipentaerythritol hexakis (3-mercaptopropionate) (SC organic) DPMP manufactured by Chemical Co., Ltd.) can be mentioned. Furthermore, pentaerythritol tetrakis (3-mercaptobutyrate), 1,4-bis (3-mercaptobutyryloxy) butane, 1,3,5-tris (3-mercaptobutyrate) sold by Showa Denko Co., Ltd. Lyloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, trimethylolpropane tris (3-mercaptobutyrate), trimethylolethanetris (3-mercaptobutyrate) ), Pentaerythritol poly (3-mercaptopropionate), 4- (mercaptomethyl) -3,6-dithiaoctane-1,8-dithiol, 4,8-bis (mercapto) sold by Mitsui Chemicals, Inc. Methyl) -3,6,9-trithiaundecane-1,11-dithiol Shikoku Kasei also sells 1,3,4,6-tetrakis (2-mercaptoethyl) glycoluryl (TS-G), etc. Can be used. In addition, ethanedithiol, propanedithiol, butanedithiol, hexamethylenedithiol, decamethylenedithiol, trilen-2,4-dithiol, xylenedithiol, diglycoldimercaptan, triglycoldimercaptan, polyoxypropylene glycol dimercaptan, tris- Known compounds such as (3-mercaptopropionyloxy) -ethyl] -isocyanurate and 1,3,5-trithiopropyl isocyanurate can also be used.

The compound of the present invention may be a single compound represented by the above general formula (1) or general formula (2), but is in the state of a mixture of a plurality of types of compounds represented by such a general formula. It may be the one used in. As a case where it is a mixture of a plurality of compounds, there is a case where it is a mixture of compounds having different reaction rates of thiol groups represented by the general formula (13) or the general formula (14) as a raw material.

The compounds represented by the general formulas (13) and (14), which are the origins of the structures represented by the general formulas (1) and (2) of the present invention, have a plurality of thiol groups. Then, by adjusting the molar ratio of the unsaturated group-containing acid anhydride to be reacted and the thiol group, an arbitrary ratio of the thiol groups in the raw material may have a sulfide group structure. Further, even if the thiol group remains, the remaining thiol group causes a curing reaction with the epoxy group, so that it does not adversely affect the effect of the present invention, but rather low-temperature curing by the thiol group. Can be expected.

In the mixture, a compound represented by the general formula (11), the general formula (12), the general formula (13) or the general formula (14) may remain as an unreacted raw material. , The composition in which such a raw material remains is also included in the present invention.

The compound of the present invention is not particularly limited as long as it has the above-mentioned structure, but examples of specific compounds are shown below.

Examples of the compound represented by the general formula (1) include the following.

Examples of the compound represented by the general formula (2) include the following.

Such a compound can be easily produced by an esterification reaction between a mercaptocarboxylic acid such as 3-mercaptopropionic acid or 3-mercaptobutanoic acid and a polyhydric alcohol such as pentaerythritol or trimethylolpropane (14). It is particularly preferable in that it is made from the compound represented by.

The compound represented by the general formula (1) or the general formula (2) includes the compound represented by the general formula (11) and / or the compound represented by the general formula (12) and the general formula (13). ) Or a composition containing the compound represented by the general formula (14), which can be obtained by a production method having a step (1) for forming a sulfide bond by an enthiol reaction.

Norbornene 2,3-dicarboxylic acid anhydride is obtained by the Diels-Alder reaction of cyclopentadiene and maleic anhydride. Normally, norbornene-2,3-dicarboxylic acid anhydride obtained by the Diels-Alder reaction of cyclopentadiene and maleic anhydride has an endo-form abundance ratio of 95% by weight or more, and therefore is heated to 150 ° C. or higher to form an exo-form. Norbornene 2,3-dicarboxylic acid anhydride having a large abundance ratio of exo (for example, norbornene 2,3-dicarboxylic acid anhydride having an exo abundance ratio of 30% by weight or more by isomerization (heat isomerization) Things) can be generated. Examples of commercially available products of the compound represented by the general formula (11) include 5-norbornene-2,3-dicarboxylic acid anhydride, trade name "MHAC-P" (manufactured by Hitachi Chemical Co., Ltd.) and the like. it can.

The method for forming a sulfide bond by the ential reaction is not particularly limited, and can be obtained by, for example, a step of performing ultraviolet irradiation or a radical reaction. Such a manufacturing method is also one of the present inventions. The general formula of such a reaction is shown below. The compound of the present invention is not limited to the compound synthesized by the following reaction formula.

An example of the reaction formula for the compound of the present invention represented by the general formula (2) is represented below.

The ultraviolet irradiation or radical reaction can be carried out in the state of an organic solvent solution. Examples of the organic solvent include compounds represented by the general formulas (1) and (2), compounds represented by the general formula (11) and / or compounds represented by the following general formula (12), and the above general formula (13). ) Or an organic solvent that dissolves the general formula (14), but is not particularly limited, and examples thereof include tetrahydrofuran.

In the above reaction, it is not necessary to react all the thiol groups in the raw material thiol compound with the compound represented by the general formula (11) and / or with the following general formula (12), and if necessary, with the thiol compound. The compound represented by the general formula (11) and / or the reaction ratio with the following general formula (12) may be adjusted to leave a thiol group.

For example, when 1 mol of a compound having 6 thiol groups in one molecule is reacted with 3 mol of an unsaturated group-containing acid anhydride, 50% of the thiol groups in the raw material are replaced with sulfide groups. .. In this case, not only 3 out of 6 thiol groups are obtained as a sulfide compound, but 50% of the thiol groups on average in the entire composition are replaced with sulfide groups. The result is a mixture of a plurality of compounds different only in the ratio of a or the ratio of b and c in the above general formula. Such a manufacturing method is also one of the present inventions.

The substitution rate of the thiol group ((number of sulfide groups) / (number of sulfide groups + number of thiol groups) in the compound represented by the general formula (1) or (2) is preferably 15 to 100%. Most preferably 70%.

The above-mentioned ultraviolet irradiation or radical reaction is carried out in an acid anhydride compound that does not correspond to the above-mentioned "acid anhydride having an unsaturated group" (hereinafter, this may be referred to as "other acid anhydride compound"). You can also do it. That is, "other acid anhydride compounds" that do not contribute to the above reaction can be used as the solvent. It is preferable to use "another acid anhydride compound" as a solvent in that when it is used as an epoxy resin curing agent, various problems due to solvent volatilization during curing can be suppressed. That is, when the epoxy resin is cured, volatilization of the solvent may cause bubbles, which may cause deterioration of the physical properties of the cured product. However, when an acid anhydride compound that does not correspond to "an acid anhydride having an unsaturated group" is used as the solvent, the acid anhydride compound acts as a curing agent and is incorporated into the resin chain of the cured product. It does not produce volatiles. This is preferable.

When the above step (1) is performed using a liquid "other acid anhydride compound" as a solvent, the "other acid anhydride compound" can also be used as an epoxy resin curing agent, so that the solvent is removed. Can be used without. Further, an epoxy resin curing agent having an arbitrary compound content represented by the general formula (1) or the general formula (2) can be obtained depending on the amount charged.

The "other acid anhydride compounds" are not particularly limited, but are Ricacid HH, Ricacid MH-700, Ricacid HNA-100 (above, manufactured by New Japan Chemical Co., Ltd.) ThreeBond2162G, ThreeBond2280C (above, Co., Ltd.). ThreeBond) and the like. Among these, it is most preferable to carry out the reaction in the presence of the above general formula (15) or general formula (16) or a mixture thereof.

The above ultraviolet irradiation can also be carried out in the epoxy compound (A). In the case of the above-mentioned reaction by irradiation with ultraviolet rays, even if an epoxy group is present in the system, an unsaturated bond and a sulfide group formation reaction due to a thiol group occur preferentially, so that in the presence of the epoxy compound (A) The compound represented by the above general formula (1) or general formula (2) can also be obtained by carrying out the reaction by irradiation with ultraviolet rays.

When the reaction is carried out in the epoxy compound (A), it is preferable to use a liquid epoxy compound because the epoxy compound also serves as a solvent.

The compound of the present invention can be used as an epoxy resin curing agent. Therefore, in the case of an epoxy resin composition, the epoxy compound (A) is an essential component. When the above step (1) is performed using the liquid epoxy compound (A) as a solvent, the epoxy resin composition can be used as it is without the treatment of mixing the epoxy resin, which simplifies the step. Can be converted. This is preferable in that it can contribute to cost reduction at the time of practical use.

For the above-mentioned ultraviolet irradiation, as a light source, an ultra-high pressure, high-pressure and low-pressure mercury lamp, ultraviolet rays from a metal halide lamp, or the like are used.

When irradiating with ultraviolet rays, a light initiator can be used if necessary. Examples of the photoinitiator include benzophenone-based photopolymerization initiators such as benzophenone, methyl orthobenzoyl benzoate, 4-benzoyl-4'-methyldiphenylsulfide, acetophenone, benzyldimethylketal, 2-hydroxy-2-methyl-1-phenyl. Acetophenone-based photopolymerization initiators such as propane-1-one and 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl Examples thereof include benzoin ether-based photopolymerization initiators such as ether, thioxanthone such as isopropylthioxanthone and diethylthioxanthone, acylphosphine oxide, benzyl, phenylquinone, anthraquinone, and Michler ketone.

When the above step (1) is carried out by a radical reaction, it is preferable to use a radical initiator. The radical initiator is not particularly limited, and examples thereof include organic peroxides, azo compounds, redox initiators, sulfur compounds, dihalogens, triethylborane, and diethylzinc. Among them, organic peroxides, azo compounds and the like can be preferably used. Examples of organic peroxides include ketone peroxides, peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxyesters, and peroxydicarbonates. Among them, diacyl peroxides, peroxyesters and peroxyesters having a relatively low decomposition temperature are preferable. Examples of the azo compound include azonitriles, azo esters, azoamides, azoamidines, and azoimidazolines. Among them, oil-soluble azonitriles and azo esters are preferable because the decomposition temperature is relatively low.

The sulfide bond formation step (1) by the radical reaction can be carried out by stirring and mixing the raw material compounds containing the radical initiator and then heating. The reaction temperature is preferably 20 to 100 ° C, particularly preferably 40 to 80 ° C. The radical reaction can be carried out in various organic solvents and in the epoxy compound (A).

As described above, it is known that an acid anhydride and a thiol compound are used in combination as a curing agent for an epoxy resin. However, in the reaction of an acid anhydride having an unsaturated group with a thiol compound, in order to obtain a compound represented by the general formula (1) or (2), a step for forming a sulfide bond by an enethiol reaction ( For example, the above-mentioned addition reaction by irradiation with ultraviolet rays or a radical reaction) is required, and the compound represented by the above-mentioned general formula (1) or (2) cannot be obtained simply by mixing.

The compound of the present invention can be suitably used as an epoxy resin curing agent. Therefore, in the epoxy resin composition containing the epoxy compound (A) and the curing agent (B), a composition using the above-mentioned compound as the curing agent (B) is also one of the present inventions.

In the epoxy resin composition of the present invention, the epoxy compound (A) is a compound having at least one epoxy group. The epoxy compound (A) is not particularly limited, and a known general epoxy compound (A) can be used. Specific examples of the compound include epoxy compounds such as bisphenol A type, bisphenol F type, cresol novolac type, phenol novolac type, biphenyl type, and hydride bisphenol A type, and alicyclic epoxy compounds.

The epoxy compound (A) can be produced by a known or commonly used method, or a commercially available product can be used. For example, examples of the bisphenol A type include jER828, jER827, jER834 (above, manufactured by Mitsubishi Chemical Corporation), EPICLON850, EPICLON840 (above, manufactured by DIC Corporation), XNR6815 (manufactured by Nagase ChemteX Corporation), and the like. .. Examples of the bisphenol F type include jER806, jER807 (above, manufactured by Mitsubishi Chemical Corporation), EPICLON830, EPICLON835 (above, manufactured by DIC Corporation), and the like. Examples of the cresol novolak type include EPICLON N-695, EPICLON N-670 (above, manufactured by DIC Corporation), EOCN-102S, EOCN-103S (above, manufactured by Nippon Kayaku Co., Ltd.) and the like. Examples of the phenol novolac type include EPICLON N-770 (manufactured by DIC Corporation) and RE-306 (manufactured by Nippon Kayaku Co., Ltd.). Examples of the biphenyl type include jER YX-4000H (manufactured by Mitsubishi Chemical Corporation). Examples of the hydrogenated bisphenol A type include EPICLON EXA7015 (all manufactured by DIC Corporation) and the like. Examples of the alicyclic epoxy compound include celloxide 2021P (manufactured by Daicel Corporation) and the like.

The epoxy compound (A) may be a mixture of two or more kinds of various epoxy compounds. Further, as the epoxy compound (A), it is preferable to use a liquid compound. The use of a liquid compound is particularly preferable in that the epoxy resin composition can be made solvent-free. Further, as described above, it is also preferable that the process can be simplified by synthesizing the compound represented by the general formula (1) or the general formula (2) among the liquid epoxy compounds.

The content (blending amount) of the epoxy compound (A) in the epoxy resin composition of the present invention is not particularly limited, but is preferably 10 to 95% by weight with respect to the total amount (100% by weight) of the epoxy resin composition. The lower limit is more preferably 40% by weight, still more preferably 45% by weight. The upper limit is more preferably 90% by weight, still more preferably 85% by weight.

The epoxy resin composition of the present invention uses the above-mentioned compound as the curing agent (B), but in addition to the compound represented by the above general formula (1) or general formula (2), further It does not matter if a known curing agent is used in combination.

The curing agent that can be used in combination with the epoxy curing compound of the present invention is not particularly limited, and for example, acid anhydrides (acid anhydride-based curing agents), amines, imidazoles, polyethercaptans, phenols, etc. Examples thereof include polycarboxylic acids, dicyandiamides, and organic acid hydrazides.

Further, as the curing agent (B), the compound represented by the general formula (11) and the compound represented by the general formula (12) may be used in combination. Even if such a compound is present in the system as a raw material remaining unreacted during the synthesis of the compound represented by the general formula (1) or the general formula (2), the composition can be prepared. It may be added at the time.

The blending ratio of the epoxy compound (A) and the curing agent (B) is not particularly limited, but 50 parts by weight to 200 parts by weight of the curing agent (B) is added to 100 parts by weight of the epoxy compound (A). It is preferable to mix in a ratio. It is preferable that the content is within the above range because good curing performance can be obtained. The above range is more preferably a ratio of 100 parts by weight to 150 parts by weight of the curing agent (B) with respect to 100 parts by weight of the epoxy compound (A).

The epoxy resin composition of the present invention may further contain a curing accelerator (C). The curing accelerator (C) in the epoxy resin composition of the present invention is a compound having a function of accelerating the reaction rate of the epoxy compound (A) when it reacts with the curing agent (B). As the curing accelerator (C), a known or commonly used curing accelerator can be used, and is not particularly limited, but for example, 1,8-diazabicyclo [5.4.0] undecene-7 (DBU) or a salt thereof (for example,). , Phenol salt, octylate, p-toluenesulfonate, formate, tetraphenylborate salt, etc.); 1,5-diazabicyclo [4.3.0] Nonen-5 (DBN) or a salt thereof (eg, phenol) Salts, octylates, p-toluene sulfonates, formates, tetraphenylborate salts, etc.); benzyl dimethylamine, 2,4,6-tris (dimethylaminomethyl) phenol, N, N-dimethylcyclohexylamine, etc. Tertiary amine; imidazole such as 2-ethyl-4-methylimidazole, 1-cyanoethyl-2-ethyl-4-methylimidazole; phosphate ester; phosphate such as ammonium phosphate; triphenylphosphine, tris (dimethoxy) Hosphins such as phosphine; phosphonium compounds such as tetraphenylphosphonium tetra (p-tolyl) borate; organic metal salts such as zinc octylate, tin octylate, zinc stearate; metal chelates such as aluminum acetylacetone complex and the like.

In the epoxy resin composition of the present invention, one type of curing accelerator (C) may be used alone, or two or more types may be used in combination. As the curing accelerator (C), the product names are "U-CAT SA 506", "U-CAT SA 102", "U-CAT 5003", and "U-CAT 18X" (all manufactured by Sun Appro Co., Ltd.). ); Product names "TPP-K", "TPP-MK" (above, manufactured by Hokuko Chemical Industry Co., Ltd.); Product name "PX-4ET" (manufactured by Nippon Chemical Industrial Co., Ltd.) You can also do it.

The content (blending amount) of the curing accelerator (C) in the epoxy resin composition of the present invention is not particularly limited, but is 0.01 to 5 with respect to 100 parts by weight of the epoxy compound (A) in the epoxy resin composition. Parts by weight are preferred. If it is less than 0.01 part by weight, the curing of curing promotion is difficult to be exhibited, and if it exceeds 5 parts by weight, no further effect of curing promotion is observed. It is more preferably 0.03 to 3 parts by weight, still more preferably 0.03 to 2 parts by weight. By setting the content of the curing accelerator (C) to 0.01 parts by weight or more, a more efficient curing promoting effect tends to be obtained. On the other hand, when the content of the curing accelerator (C) is 5 parts by weight or less, coloring is suppressed and a cured product having an excellent hue tends to be obtained.

The epoxy resin composition of the present invention may contain components (arbitrary components) other than the above-mentioned essential components. When a compound having a hydroxy group such as ethylene glycol, diethylene glycol, propylene glycol, or glycerin is contained as the additive, the curing reaction can be allowed to proceed slowly. In addition, silicone-based and fluorine-based defoaming agents, leveling agents, and silane coupling agents such as γ-glycidoxypropyltrimethoxysilane and 3-mercaptopropyltrimethoxysilane, as long as the viscosity and transparency are not impaired. , Surfactants, inorganic fillers such as silica and alumina, flame retardants, colorants, antioxidants, UV absorbers, ion adsorbents, pigments, phosphors (for example, YAG-based phosphor particles, silicate-based phosphors) Conventional additives such as inorganic phosphor fine particles such as fine particles), a mold release agent, and rubber particles (for example, rubber particles having a core-shell structure) can be used.

The epoxy resin composition of the present invention is not particularly limited, but can be prepared by stirring and mixing each of the above-mentioned components in a heated state, if necessary. The epoxy resin composition of the present invention can be used as a one-component composition in which each component is mixed in advance and used as it is. For example, two or more components stored separately can be used. Can also be used as a multi-component (for example, two-component) composition which is used by mixing in a predetermined ratio before use. The method of stirring / mixing is not particularly limited, and for example, known or conventional stirring / mixing means such as various mixers such as a dissolver and a homogenizer, a kneader, a roll, a bead mill, and a self-revolving stirring device can be used. Further, after stirring and mixing, defoaming may be performed under vacuum.

A cured product having high heat resistance and flexibility by curing the epoxy resin composition of the present invention (the cured product obtained by curing the epoxy resin composition of the present invention is referred to as "cured product of the present invention". In some cases) can be obtained.

As the curing means, known means such as heat treatment can be used. The temperature for curing by heating (curing temperature) is not particularly limited, but is preferably 45 to 200 ° C, more preferably 50 to 190 ° C, and even more preferably 55 to 180 ° C. The heating time (curing time) at the time of curing is not particularly limited, but is preferably 30 to 600 minutes, more preferably 45 to 540 minutes, and even more preferably 60 to 480 minutes. If the curing temperature and the curing time are lower than the lower limit of the above range, the curing becomes insufficient, and conversely, if it is higher than the upper limit of the above range, the resin component may be decomposed, which is not preferable. The curing conditions depend on various conditions, and can be appropriately adjusted, for example, by shortening the curing time when the curing temperature is high and lengthening the curing time when the curing temperature is low. Further, the curing can be performed in one step or in multiple steps of two or more steps.

Further, a compound represented by the general formula (11) and / or a compound represented by the general formula (12), a compound represented by the general formula (13) or the general formula (14), an epoxy compound (A), curing. A compound represented by the general formula (11) and / or a compound represented by the following general formula (12) are obtained by molding the composition containing the auxiliary agent (C) into a predetermined shape and then irradiating with ultraviolet rays. An epoxy resin cured product can also be obtained by forming a curing agent (B) by the reaction of a compound represented by the following general formula (13) or the following general formula (14) and then performing thermosetting.

The epoxy resin composition of the present invention can be used for various purposes such as a sealant, an adhesive, a coating, an ink, and a paint.

Hereinafter, the present invention will be described in detail based on Examples, but the present invention is not limited to these Examples.

Example 1 30.0 g (0.06 mol) of PEMP (pentaerythritol tetrakis (3-mercaptopropionate) SC Organic Chemical Co., Ltd.) and 62 mL of tetrahydrofuran (THF) were charged in a reaction vessel and stirred at room temperature. Subsequently, 21.9 g (0.12 mol) of 5-norbornene-2,3-dicarboxylic acid anhydride (MHAC-P; manufactured by Hitachi Chemical Co., Ltd.) was added, and then UV was irradiated at a reaction temperature of 45 ° C. for 180 minutes. .. After confirming that the reaction was proceeding quantitatively by NMR, THF was distilled off under reduced pressure to obtain a desired curing agent as a residue.

In the implementation of Example 1, a ¹ H-NMR chart of the raw materials PEMP, MHAC-P and the compound obtained by the reaction is shown in FIG. From FIG. 1, it was observed that the vinylene peak (δ5.8 to 6.4 ppm) of MHAC-P disappeared by the reaction, and it is clear that the compound of the present invention was obtained.

Examples 2-3: (Reaction in acid anhydride) Using the thiol described in the table below as a raw material, tetrahydrofuran is used as Ricacid MH-700 (New Japan Chemical Co., Ltd .; 4-methylhexahydrophthalic anhydride / phthalic anhydride). The mixture was changed to acid = 70/30 mixture), and the production was carried out in the same manner as in Example 1 described above with the charged amounts shown in the table below, but the liquid anhydride was not distilled off under reduced pressure.

In addition, FIG. 2 shows the charts of ¹ H-NMR of Ricacid MH-700, MHAC-P, Example 2 and Example 3, respectively, so that they can be compared. From FIG. 2, it is clear that the vinylene peak (δ5.8 to 6.4 ppm) of MHAC-P disappeared also in the compositions of Examples 2 and 3, and the compound of the present invention was obtained. Is.

Examples 4 to 5: (Reaction in the epoxy compound) PEMP was used as a raw material as the thiol compound, the solvent was changed to the epoxy compound shown in the table below, and the charged amount shown in the table below was used with Example 1 described above. The production was carried out in the same manner, but the epoxy compound was not distilled off under reduced pressure.

In addition, FIG. 3 is shown so that the ¹ H-NMR charts of Ricacid MH-700, MHAC-P, Example 4 and Example 5 can be compared with each other. From FIG. 3, it is clear that the vinylene peak (δ5.8 to 6.4 ppm) of MHAC-P disappeared also in the compositions of Examples 4 and 5, and the compound of the present invention was obtained. Is. From the integrated value of the vinylene peak, it was clarified that the reaction rate was 92% in Example 4 and 96% in Example 5.

Examples 6 and 7: Epicron 850 Resin Composition Ammonium Phosphate (U-CAT 18X, San Apro Co., Ltd.) as a curing accelerator in a mixed solution of Epicron 850 and the acid anhydride compound solution of the compounds obtained in Examples 2 and 3 above. 1.0 wt% (manufactured by the company) was added, and stirring and defoaming were performed by Rentaro Awatori (manufactured by Shinky Co., Ltd.). The resin could be cured without any problem by pouring the obtained solution into a frame mold, heating at 135 ° C. for 5 hours, and then heating at 165 ° C. for 1 hour to cure.

Examples 8 to 11: Resin composition As shown in the table below, epoxy compounds (
A), ammonium phosphate (U-CAT 18X) as a curing accelerator (C) was added to a mixed solution composed of an acid anhydride compound as a curing agent (B) in the amount shown in the table below, and the same as in Example 6. The resin could be cured without any problem by the same operation.

Comparative Example 1: Epicron 850 resin composition (cured with general-purpose acid anhydride) 15.0 g of Epicron 850 and 13.5 g of Ricacid MH-700 were mixed, and stirred and defoamed by Rentaro Awatori (manufactured by Shinky Co., Ltd.). Was done. After the solution was made uniform, 0.130 g of ammonium phosphate (U-CAT 18X) was added, followed by stirring and defoaming with Awatori Rentaro. The obtained solution was poured into a frame mold, heated at 135 ° C. for 5 hours, and then heated at 165 ° C. for 1 hour to cure.

Comparative Example 2: Epicron 850 resin composition (cured with a thiol compound and an acid anhydride mixture) PEMP 3.4 g, MHAC-P 2.4 g, Ricacid MH-700 8.7 g and Epicron 850 15. 0 g was mixed, and the mixture was stirred and defoamed by Rentaro Awatori. After the solution was made uniform, 0.094 g of ammonium phosphate (U-CAT 18X) was added, followed by stirring and defoaming with Awatori Rentaro. The obtained solution was poured into a frame mold, heated at 135 ° C. for 5 hours, and then heated at 165 ° C. for 1 hour to cure.

In Comparative Example 2, the composition of the raw material itself is the same as that in Example 2, but since ultraviolet irradiation is not performed, the structure of the compound represented by the general formula (1) of the present invention can be obtained. It is not.

The following evaluations were carried out on the cured products obtained in Examples 6 to 11, Comparative Example 1 and Comparative Example 2.

(1) Thermogravimetric-Differential Thermal Analysis (TG-DTA) A cured product using a thermogravimetric-differential thermal analyzer (Hitachi High Technology Co., Ltd. STA7300) by a method conforming to JIS K-7120. The temperature rise rate was set to 10 ° C./min., And the thermal weight loss under a nitrogen atmosphere was measured. The temperature when the weight was reduced by 5% was defined as the thermal decomposition temperature (Td ₅ ), and the temperature when the weight was reduced by 10% was defined as the thermal decomposition temperature (Td ₁₀ ).

(2) Bending modulus A test piece having a thickness of 3 mm, a width of 10 mm, and a length of 70 mm is cut out from the cured product, and JIS K-6911 is used with a precision universal testing machine (Autograph AGS-X manufactured by Shimadzu Corporation). The flexural modulus was calculated by performing a three-point bending test at a load rate of 1.5 mm / min by a method according to the above.

(3) Water absorption rate The cured product was placed in a flask, sufficiently immersed in water was added, and subjected to a water resistance test at 1 atm for 24 hours under reflux. It was appropriately allowed to cool to room temperature, taken out, wiped with water on the surface, weighed, and the water absorption rate was calculated.

(4) Regarding the cured hue, the sample piece under normal conditions and the sample piece after the water absorption rate measurement were measured using SQ2000 manufactured by Nippon Denshoku Industries Co., Ltd. and evaluated by the YI value.

(5) Transmittance The transmittance of the cured product was measured using a UV-Vis Spectrophotometer V-570 manufactured by JASCO Corporation.

The analysis results are shown in Table 4.

As shown in Table 4, the epoxy resin composition obtained in the present invention has excellent heat resistance and flexibility of 300 ° C. or higher, and also has high transmittance, water resistance, and high transparency. It is clear that it has. Therefore, the epoxy resin composition obtained in the present invention can be used in a wide range of applications, and can be particularly preferably used in optical applications.

The compound of the present invention can be used as a curing agent for epoxy resins. The epoxy resin composition using the compound of the present invention can be used in applications such as encapsulants, adhesives, coatings, inks, and paints. In particular, it can be suitably used in optical applications.

Claims

A compound for curing an epoxy, which is represented by the following general formula (1) or general formula (2).

(In the general formula (1), A may have a substituent and may have a functional group containing a hetero atom in the main chain and / or the side chain, and has 2 to 50 carbon atoms. A and S are connected without intervening atoms. A represents an integer of 2 to 6).

(In the general formula (2), Rs is a hydrogen or a methyl group. R has a linear or branched or cyclic structure having 2 to 28 carbon atoms which may have a functional group containing a hetero atom. R'represents at least one selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a thiol group, and a functional group represented by the following general formula (5). B and c are b + c. = 2 to 6, b is an integer including 0, and c is an integer of 1 to 6.) In the general formulas (1) and (2), Rx is the same or different, hydrogen.

as well as

(In the general formulas (3) and (4), R 1 to R 10 represent hydrogen atoms or linear or branched alkyl groups having 1 to 4 carbon atoms, which are the same or different, and wavy lines indicate binding sites. It is a structure selected from the group consisting of (represented), and one or more of Rx is a structure represented by the general formula (3) or (4).

(In the general formula (5), R 11 and R 12 are different, R 11 represents a thiol group or a methyl group, R 12 represents a hydrogen atom or a thiol group. Wavy lines represent bond sites.)
The epoxy curing compound according to claim 1, wherein R has any of the structures represented by the following general formulas (6) to (10).

(N indicates an integer from 1 to 10.)

(In the general formulas (6) to (10), the wavy line represents the binding site.)
An epoxy resin composition containing at least an epoxy compound (A) and a curing agent (B), wherein the curing agent (B) is the epoxy curing compound according to claims 1 and 2. Epoxy resin composition to be used.
The epoxy resin composition according to claim 3, further comprising a curing accelerator (C).
An acid anhydride compound represented by the following general formula (11) and / or an acid anhydride compound represented by the following general formula (12) and a thiol compound represented by the following general formula (13) or the general formula (14). The method for producing an epoxy curing compound according to claim 1 or 2, further comprising a step (1) for forming a sulfide bond by an enthiol reaction with a composition containing and.

(In the general formulas (11) and (12), R 1 to R 10 represent hydrogen atoms or linear or branched alkyl groups having 1 to 4 carbon atoms, which are the same or different.)

(In the general formula (13), A may have a substituent and may have a functional group containing a heteroatom in the main chain and / or the side chain, and has 2 to 50 carbon atoms. A and S are connected without intervening atoms. D represents an integer of 2 to 6).

(In the general formula (14), Rs is a hydrogen or methyl group. R has a linear, branched or cyclic structure having 2 to 28 carbon atoms which may have a functional group containing a hetero atom. R ″ indicates at least one selected from a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, a thiol group, and a functional group represented by the following general formula (5). E and f are. e + f = 2 to 6, e is an integer including 0, and f is an integer of 1 to 6).

(In the general formula (5), R 11 and R 12 are different, R 11 represents a thiol group or a methyl group, R 12 represents a hydrogen atom or a thiol group. Wavy lines represent bond sites.)
The production method according to claim 5, wherein the thiol compound is a compound represented by the general formula (14).
The production method according to claim 5 or 6, wherein the step (1) is performed in the presence of the epoxy compound (A).
The production method according to claim 5, 6 or 7, wherein the step (1) is performed in the presence of an acid anhydride compound composed of the general formula (15), the general formula (16), or a mixture thereof.