JP5200805B2 - One-component thermosetting epoxy resin composition - Google Patents

Description

  The present invention relates to a one-component thermosetting epoxy resin composition.

Conventionally, a composition using a thiol compound and a latent amine compound in combination as a curing agent for an epoxy resin has been proposed (for example, Patent Document 1). A composition using a thiol compound and a latent amine compound in combination as a curing agent for an epoxy resin is excellent in low-temperature curability and has a good pot life.
In addition, the applicant of the present application is a curable resin composition using an epoxy-silica hybrid body, which has better heat resistance than a conventional composition, and particularly changes in storage elastic modulus (G ′) from low temperature to high temperature. In addition, for the purpose of providing a curable resin composition that is excellent in low-temperature curability and easy to handle, 100 parts by mass of an epoxy resin and an alkoxysilane containing at least a mercapto group-containing alkoxysilane are hydrolyzed and condensed. A curable resin composition containing 20 to 200 parts by mass of a mercapto group-containing silicone compound obtained in this manner was proposed (Patent Document 2).

JP 2000-230112 A JP 2006-22146 A

However, when the present inventor uses a thiol compound as a curing agent for an epoxy resin to form a one-component composition, such a composition has poor storage stability, and the resulting cured product has a low glass transition temperature. For this reason, it discovered that a use was limited in many cases.
Then, an object of this invention is to provide the one-pack type thermosetting epoxy resin composition which is excellent in storage stability and can become a hardened | cured material with a high glass transition temperature.

  As a result of intensive studies to solve the above problems, the present inventor has found that an epoxy resin (A), a mercapto group-containing silicone (B) having two or more mercapto groups in the molecule, an amine adduct-based latent curing agent ( The one-pack type thermosetting epoxy resin composition containing C) was found to be a cured product having excellent storage stability and a high glass transition temperature, and the present invention was completed.

That is, this invention provides the following 1-6.
1. A one-component thermosetting epoxy resin composition comprising an epoxy resin (A), a mercapto group-containing silicone (B) having two or more mercapto groups in the molecule, and an amine adduct latent curing agent (C).
2. The one-component thermosetting epoxy resin composition according to the above 1, further comprising a boric acid ester and / or a sulfonium salt.
3. The one-pack type thermosetting epoxy resin composition according to the above 1 or 2, wherein the mercapto group-containing silicone (B) is represented by the following formula (1).

(In the formula, R ¹ is an alkyl group, R is an alkylene group, R ² is an alkyl group or an alkoxy group, R ³ is an alkyl group, and n is an integer of 2 or more.)
4). One of said 1-3 whose said amine adduct type | system | group latent hardening | curing agent (C) is an adduct body of at least 1 compound chosen from the group which consists of an epoxy resin, an isocyanate compound, and a urea compound, and an amine. Liquid type thermosetting epoxy resin composition.
5. Any one of the above items 2 to 4, wherein the borate ester is at least one selected from the group consisting of trimethyl borate, triethyl borate, triphenyl borate, triisopropyl borate, tri-n-butyl borate and tripentyl borate. One-component thermosetting epoxy resin composition.
6). The ratio of the mercapto group to the epoxy group of the epoxy resin (A) (number of moles of the mercapto group / number of moles of the epoxy group) is 0.5 to 1.2, and the amine adduct latent curing is performed. The amount of the agent (C) is 1 to 30 parts by mass with respect to 100 parts by mass of the epoxy resin (A), and the amount of the boric acid ester and / or the sulfonium salt is 100 parts by mass of the epoxy resin (A) 100. The one-component thermosetting epoxy resin composition according to any one of 2 to 5, which is 0.1 to 10 parts by mass with respect to part by mass.

  The one-component thermosetting epoxy resin composition of the present invention can be a cured product having excellent storage stability and a high glass transition temperature.

The present invention will be described in detail below.
The one-component thermosetting epoxy resin composition of the present invention is
A composition comprising an epoxy resin (A), a mercapto group-containing silicone (B) having two or more mercapto groups in the molecule, and an amine adduct-based latent curing agent (C).
The one-component thermosetting epoxy resin composition of the present invention may be hereinafter referred to as “the composition of the present invention”.

The epoxy resin (A) will be described below.
The epoxy resin (A) contained in the composition of the present invention is not particularly limited as long as it is a compound having an average of 2 or more epoxy groups in one molecule. For example, polyglycidyl ethers obtained by reacting polychlorophenols such as bisphenol A, bisphenol F, bisphenol AD, catechol, resorcinol, polyhydric alcohols such as glycerin and polyethylene glycol and epichlorohydrin; p-hydroxybenzoic acid, Glycidyl ether ester obtained by reacting a hydroxycarboxylic acid such as β-hydroxynaphthoic acid with epichlorohydrin; a polyglycol obtained by reacting a polycarboxylic acid such as phthalic acid or terephthalic acid with epichlorohydrin Glycidyl ester; epoxidized phenol novolak resin, epoxidized cresol novolak resin, epoxidized polyolefin, cycloaliphatic epoxy resin, urethane-modified epoxy resin, dicyclopentadiene type epoxy resin, 4 4 diaminodiphenylmethane and m- aminophenol such as glycidyl amine type epoxy resins obtained from naphthalene type epoxy resins, biphenyl type epoxy resins, and the like.
The epoxy resin (A) is superior in storage stability, can be a cured product having a higher glass transition temperature, and is excellent in rapid curability from the viewpoint of bisphenol A, dicyclopentadiene type epoxy resin, glycidylamine type. Epoxy resins are preferred.
An epoxy resin (A) can be used individually or in combination of 2 types or more, respectively.

The mercapto group-containing silicone (B) will be described below.
The mercapto group-containing silicone (B) contained in the composition of the present invention is a compound having two or more mercapto groups (—SH) in the molecule, and the main chain is a silicone skeleton.
In the present invention, the mercapto group-containing silicone (B) is used as a curing agent for the epoxy resin (A).

The number of mercapto groups contained in one molecule of the mercapto group-containing silicone (B) is excellent in storage stability, can be a cured product having a higher glass transition temperature, and is excellent in curability from the viewpoint of being excellent in curability. The number is preferably one, and more preferably 6 to 8.
The mercapto group can be directly bonded to the main chain of the mercapto group-containing silicone (B). The mercapto group can be bonded to the main chain of the mercapto group-containing silicone (B) via an organic group.

  The organic group through the mercapto group and the main chain of the mercapto group-containing silicone (B) is not particularly limited as long as it is a divalent hydrocarbon group. The divalent hydrocarbon group can have a hetero atom such as an oxygen atom, a nitrogen atom, or a sulfur atom. Examples of the divalent hydrocarbon group include an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, and a hydrocarbon group formed by a combination thereof. Especially, an aliphatic hydrocarbon group is preferable from a viewpoint that the glass transition temperature (glass transition point) of hardened | cured material is higher, and it is excellent in quick curability and storage stability. Examples of the aliphatic hydrocarbon group include those having 2 to 6 carbon atoms. Specific examples include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group.

  The main chain of the mercapto group-containing silicone (B) can have, for example, an alkoxy group such as a methoxy group and an ethoxy group; an alkyl group such as a methyl group and an ethyl group in addition to the mercapto group.

As a mercapto group containing silicone (B), the compound represented by following formula (1) is mentioned, for example. The mercapto group-containing silicone (B) is a compound represented by the formula (1) from the viewpoint that it is excellent in storage stability, can be a cured product having a higher glass transition temperature, and is excellent in rapid curability. Is preferred.

In the formula, R ¹ is an alkyl group, R is an alkylene group, R ² is an alkyl group or an alkoxy group, R ³ is an alkyl group, and n is an integer of 2 or more.

Examples of the alkyl group include a methyl group and an ethyl group.
Examples of the alkylene group include those having 2 to 6 carbon atoms, and specific examples include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group.
Examples of the alkyl group or alkoxy group represented by R ² include a methyl group and a methoxy group. Examples of the alkyl group as R ³ include a methyl group.
n is an integer greater than or equal to 2, and it is preferable that it is 5-10 from a viewpoint that the glass transition temperature (glass transition point) of hardened | cured material is higher, and it is excellent in quick curability and storage stability, and is 6-8. More preferably.

As a compound represented by Formula (1), the compound represented by following formula (2) is mentioned, for example. The compound represented by the formula (1) is excellent in storage stability, can be a cured product having a higher glass transition temperature, and is a compound represented by the formula (2) from the viewpoint of excellent rapid curability. Is preferred.

In the formula, R ¹ is an alkyl group, R ² is an alkyl group or an alkoxy group, R ³ is an alkyl group, and n is an integer of 2 or more. R ¹ , R ² , R ³ , and n are as defined above.
The mercapto group-containing silicone (B) can be used alone or in combination of two or more.

The mercapto group-containing silicone (B) is not particularly limited for its production. For example, it can be produced by condensing a mercapto group-containing alkoxysilane compound.
The mercapto group-containing alkoxysilane compound is a silane compound having at least one mercapto group and at least two alkoxy groups. The mercapto group-containing alkoxysilane compound can have an alkyl group such as a methyl group or an ethyl group in addition to the mercapto group and the alkoxy group.
A mercapto group can be bonded to a silicon atom via an organic group. The organic group is as defined above.

As a mercapto group containing alkoxysilane compound, the compound represented by following formula (3) is mentioned, for example.

In the formula, R ¹ and R ⁴ are each independently an alkyl group, R is an alkylene group, m is 2 or 3, n is 1 or 2, and m + n is 3 or 4.
R ¹ and R are as defined above. Examples of the alkyl group as R ⁴ include a methyl group and an ethyl group.

  Examples of mercapto group-containing alkoxysilane compounds include 3-mercaptopropyltrimethoxysilane and 3-mercaptopropyltrialkoxysilane such as 3-mercaptopropyltriethoxysilane; 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropylmethyl. Examples include 3-mercaptopropylalkyldialkoxysilanes such as diethoxysilane.

The method for condensing the mercapto group-containing alkoxysilane compound is not particularly limited. For example, a method of hydrolyzing and condensing a composition containing at least a mercapto group-containing alkoxysilane compound can be mentioned.
The composition containing at least the mercapto group-containing alkoxysilane compound can contain an alkoxysilane other than the mercapto group-containing alkoxysilane. Alkoxysilanes other than mercapto group-containing alkoxysilanes are not particularly limited. For example, a conventionally well-known thing is mentioned.

  The amount of the mercapto group-containing silicone (B) is superior to the storage stability, can be a cured product having a higher glass transition temperature, and is excellent in curability, with respect to the epoxy group of the epoxy resin (A). The mercapto group ratio (number of moles of mercapto group / number of moles of the epoxy group) of the mercapto group-containing silicone (B) is preferably 0.5 to 1.2, preferably 0.7 to More preferably, it is 0.9.

The amine adduct-based latent curing agent (C) will be described below.
The amine adduct-based latent curing agent (C) contained in the composition of the present invention is an amine adduct, a solid that is insoluble in an epoxy resin at room temperature, and is solubilized by heating and functions as a curing agent. is there.
The amine adduct-based latent curing agent (C) can be dissolved at 80 to 150 ° C.
In the present invention, the amine adduct latent curing agent (C) is used as a curing accelerator.

As an amine adduct type | system | group latent hardening | curing agent (C), the adduct body of an amine and at least 1 compound chosen from the group which consists of an epoxy resin, an isocyanate compound, and a urea compound is mentioned, for example.
The amine adduct-based latent curing agent (C) is an amine and at least one compound selected from the group consisting of an epoxy resin, an isocyanate compound, and a urea compound from the viewpoint of excellent storage stability and excellent quick curability. An adduct body is preferred.

  Examples of the amine used in the production of the amine adduct-based latent curing agent (C) include one or more active hydrogens that can undergo an addition reaction with an epoxy group, a phenol group, or an isocyanate group, and What is necessary is just to have at least 1 sort (s) chosen from the group which consists of a primary amino group, a secondary amino group, and a tertiary amino group in 1 molecule. Specifically, for example, 2-methylimidazole, N-methylimidazole, 2-ethyl-4-methylimidazole, N-methylpiperazine, 2,4,6-tris (dimethylaminomethyl) phenol, 2-dimatilaminoethanol, Examples include 2-undecylimidazole, 2-phenylimidazole, and 2-octadecylimidazole.

  The epoxy resin used in the production of the amine adduct latent curing agent (C) is not particularly limited. For example, polyglycidyl ethers obtained by reacting polychlorophenols such as bisphenol A, bisphenol F, bisphenol AD, catechol, resorcinol, polyhydric alcohols such as glycerin and polyethylene glycol and epichlorohydrin; p-hydroxybenzoic acid, Glycidyl ether ester obtained by reacting a hydroxycarboxylic acid such as β-hydroxynaphthoic acid with epichlorohydrin; a polyglycol obtained by reacting a polycarboxylic acid such as phthalic acid or terephthalic acid with epichlorohydrin Glycidyl ester; epoxidized phenol novolak resin, epoxidized cresol novolak resin, epoxidized polyolefin, cycloaliphatic epoxy resin, urethane-modified epoxy resin, 4,4 diaminodiphenylmethane and m-a Glycidylamine epoxy resins obtained from such Bruno phenol.

  The isocyanate compound used in the production of the amine adduct latent curing agent (C) is not particularly limited. For example, monofunctional isocyanate compounds such as n-butyl isocyanate, phenyl isocyanate, hexamethylene diisocyanate; hexamethylene diisocyanate, toluylene diisocyanate, 1,5-naphthalene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, 1,3,6-hexa A polyfunctional compound such as methylene triisocyanate is exemplified.

  The urea compound used in the production of the amine adduct-based latent curing agent (C) is not particularly limited as long as it is a compound having at least one selected from the group consisting of a ureido bond, a ureylene bond, and NH—CO—N. For example, urea, urea phosphate, urea oxalate, urea acetate, diacetylurea, dibenzoylurea, and trimethylurea are listed.

The amine adduct-based latent curing agent (C) is not particularly limited for its production. For example, a conventionally well-known thing is mentioned.
The amine adduct-based latent curing agent (C) can be used alone or in combination of two or more.

  The amount of the amine adduct-based latent curing agent (C) is 1 to 30 parts by mass with respect to 100 parts by mass of the epoxy resin (A) from the viewpoint of excellent storage stability and excellent quick curing. It is preferably 20 to 30 parts by mass.

The composition of the present invention preferably further contains a boric acid ester and / or a sulfonium salt from the viewpoint that it is excellent in storage stability and can be a cured product having a higher glass transition temperature.
In the composition of the present invention, borate ester and / or sulfonium salt is used as a storage stabilizer for amine adduct-based latent curing agent, mercapto group-containing silicone.

  Examples of the boric acid ester that can be contained in the composition of the present invention include trimethyl borate, triethyl borate, tri-n-propyl borate, triisopropyl borate, tri-n-butyl borate, tripentyl borate, trihexyl borate, Trioctyl borate, trinonyl borate, tridecyl borate, tridodecyl borate, trihexadecyl borate, trioctadecyl borate, bis (1,4,7,10-tetraoxaundecyl) (1,4,7,10,13 -Borate esters having saturated aliphatic hydrocarbon groups such as pentaoxatetradecyl) (1,4,7-trioxaundecyl) borane, tris (2-ethylhexyloxy) borane; such as triallyl borate Boric acid ester having unsaturated aliphatic hydrocarbon group A boric acid ester having an alicyclic aliphatic hydrocarbon group such as tricyclohexyl borate; an aromatic hydrocarbon group such as tribenzyl borate, triphenyl borate, tri-o-tolyl borate, tri-m-tolyl borate Boric acid ester having a triethanolamine borate.

Among these, trimethyl borate, triethyl borate, triphenyl borate, triisopropyl borate, tri-n-butyl borate, and tripentyl from the viewpoint of being excellent in storage stability and capable of being a cured product having a higher glass transition temperature. Borate is preferred.
Boric acid esters can be used alone or in combination of two or more.

The sulfonium salt that can be contained in the composition of the present invention is not particularly limited. For example, the compound represented by following formula (4) is mentioned.

In the formula, R ¹ , R ² and R ³ each independently represent a hydrocarbon group. The hydrocarbon group is not particularly limited.
X ⁻ which is an anionic species is not particularly limited. Examples thereof include CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , PF ₆ ⁻ and SbF ₆ ⁻ .

Among these, SbF ₆ ⁻ is preferable from the viewpoint of excellent storage stability and a cured product having a higher glass transition temperature.
Examples of commercially available compounds represented by the formula (4) where X ⁻ is SbF ₆ ^— include trade names Sun-Aid SI-60L and Sun-Aid SI-100L (manufactured by Sanshin Chemical Industry Co., Ltd.).
The sulfonium salts can be used alone or in combination of two or more.

  The amount of the borate ester and / or the sulfonium salt is better than the storage stability, and can be a cured product having a higher glass transition temperature, with respect to 100 parts by mass of the epoxy resin (A). It is preferable that it is 1-10 mass parts, and it is more preferable that it is 0.5-5 mass parts.

  In addition to the epoxy resin (A), the mercapto group-containing silicone (B), the amine adduct-based latent curing agent (C), and the boric acid ester and / or sulfonium salt, the composition of the present invention is added as necessary. An agent can be included. Examples of the additive include a filler (for example, silica, calcium carbonate, etc.), a diluent, a solvent, a pigment, a flexibility imparting agent, a coupling agent, an antioxidant, a thixotropic property imparting agent, and a dispersing agent. .

  The composition of the present invention is not particularly limited for its production. For example, epoxy resin (A), mercapto group-containing silicone (B), amine adduct-based latent curing agent (C), and borate ester and / or sulfonium salt, additives that can be used as necessary By mixing uniformly using a stirrer, it can be produced as a one-pack type epoxy resin composition.

The composition of the present invention is thermosetting, and the composition of the present invention can be cured under conditions of 80 to 200 ° C. When the composition of the present invention is heated, the amine adduct latent curing agent (C) is dissolved, and the dissolved amine adduct latent curing agent (C) activates the mercapto group of the mercapto group-containing silicone (B). By reacting with the epoxy resin (A), the composition of the present invention can be cured.
Moreover, since the composition of this invention can be hardened | cured at the above temperatures, it is excellent in low temperature curability.

The composition of the present invention can be used, for example, for adhesives, paints, civil engineering and construction, electricity, transportation equipment, medical use, packaging use, textile use, and sports / leisure use.
Examples of the adherend to which the composition of the present invention can be applied include metal, glass, plastic, mortar, concrete, rubber, wood, leather, cloth, and paper.

Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these.
1. Evaluation About the composition obtained as follows, glass transition temperature, storage stability, and sclerosis | hardenability were evaluated by the method shown below. The results are shown in Table 1.
(1) Glass transition temperature The composition obtained as described below was cured in an oven at 150 ° C. for 1 hour, and the cured product was subjected to dynamic mechanical analysis (Dynamic Mechanical Analysis) with a strain of 0.01%, a frequency of 10 Hz, and an increase. The storage elastic modulus (G ′) was measured by forced stretching and excitation in the temperature range from room temperature to 200 ° C. under a temperature rate of 5 ° C./min.

(2) Storage stability The composition obtained as described below was stored in a thermostatic bath at 25 ° C., and the number of days until the composition was no longer fluid was measured.
(3) Curability
According to the hot plate method of JIS C2161: 1997, the gel time at 100 ° C. and 150 ° C. was measured on a hot plate.

2. Manufacture of a composition The components shown in Table 1 were used in the amounts (parts by mass) shown in the same table, stirred with a stirrer and mixed uniformly to prepare a composition.
In addition, the numerical value in the parenthesis of the mercapto group-containing silicone (B) is an equivalent ratio of the SH group (mercapto group) of the mercapto group-containing silicone (B) to the epoxy group of the epoxy resin (A).
The numerical value in the parenthesis of TMTG is the equivalent ratio of SH group (mercapto group) of TMTG to the epoxy group of the epoxy resin (A).
Moreover, the quantity of a filler is shown as mass% (wt%) in the obtained whole composition.

Each component shown in Table 1 is as follows.
Epoxy resin (A): Trade name EP4100E, ADEKA epoxy resin, epoxy equivalent 188 g / mol
Mercapto group-containing silicone (B): Product name Z6062H, manufactured by Toray Dow Corning Co., Ltd., condensate of mercapto group-containing silane compound represented by the following formula, SH equivalent 139 g / mol

In the formula, n is 6-8.
TMTG: Trimethylolpropane tristhioglycolate represented by the following formula, manufactured by Sakai Chemical Co., Ltd.

・ Amine adduct-based latent curing agent (C) 1: Trade name Amicure MY-H, amine adduct-type latent curing agent manufactured by Ajinomoto Fine Techno Co., Ltd. ・ Amine adduct-based latent curing agent (C) 2: Trade name Amicure PN23J, Ajinomoto Fine-Techno Co. amine adduct type latent curing agent, a sulfonium salt: trade name San-Aid SI100L, available from Sanshin Chemical Industry Co., Ltd., a boric acid ester: B (OEt) _3, Tokyo Kasei Co., Ltd., filler: silica ( (Product name SE5050, manufactured by Admatechs)

As is clear from the results shown in Table 1, Comparative Examples 1 to 4 containing a polythiol other than the mercapto group-containing silicone (B) are inferior in storage stability, and the glass transition temperature of the resulting cured product is less than 60 ° C. It was low.
On the other hand, Examples 1-4 and Reference Examples 1-4 were excellent in storage stability, the glass transition temperature of the hardened | cured material obtained was high, and all the glass transition temperatures were 90 degreeC or more.
In addition, Examples 1 to 3 and Reference Examples 1 to 3 have low-temperature curability equivalent to or better than that of the prior art.

Claims (6)

One-component thermosetting comprising an epoxy resin (A), a mercapto group-containing silicone (B) having two or more mercapto groups in the molecule, an amine adduct latent curing agent (C) , and a sulfonium salt Epoxy resin composition. The one-pack type thermosetting epoxy resin composition according to claim 1, wherein the mercapto group-containing silicone (B) is represented by the following formula (1).

(In the formula, R ¹ is an alkyl group, R is an alkylene group, R ² is an alkyl group or an alkoxy group, R ³ is an alkyl group, and n is an integer of 2 or more.) The one-pack type according to claim 1 or 2 , wherein the amine adduct-based latent curing agent (C) is an adduct body of at least one compound selected from the group consisting of an epoxy resin, an isocyanate compound, and a urea compound and an amine. Thermosetting epoxy resin composition. The ratio of the mercapto group to the epoxy group of the epoxy resin (A) (number of moles of the mercapto group / number of moles of the epoxy group) is 0.5 to 1.2, and the amine adduct latent curing is performed. the amount of agent (C) is, relative to the epoxy resin (a) 100 parts by mass of a 1 to 30 parts by weight, the amount of pre-Symbol sulfonium salt, relative to the epoxy resin (a) 100 parts by mass of, It is 0.1-10 mass parts, The one-component thermosetting epoxy resin composition in any one of Claims 1-3 . The one-component thermosetting epoxy resin composition according to any one of claims 1 to 4, wherein the sulfonium salt is a compound represented by the following formula (4).

(Wherein R ¹ , R ² , R ^Three Each independently represents a hydrocarbon group. X ^- Is CF _Three SO _Three ^- , (CF _Three SO ₂ ) ₂ N ^- , PF ₆ ^- Or SbF ₆ ^- It is. ) The one-component thermosetting epoxy resin composition according to any one of claims 1 to 5, which is cured under conditions of 80 to 200 ° C.