JP2015093887A - Epoxy resin composition and cure product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition which is excellent in easy curability at a low temperature (low temperature curability) and excellent in hardness after curing, and to provide a cured product having high hardness produced by using the epoxy resin composition.SOLUTION: There is provided an epoxy resin composition which comprises an epoxy resin having two or more epoxy groups in the molecule, a thiol compound having two or more mercapto groups in the molecule and a solid dispersion-type amine adduct-based latent curing accelerator, where the mixture ratio of the epoxy resin and the thiol compound is 0.10 or more and 0.45 or less at a ratio (X/X) of the number of SH equivalents (X) of the thiol compound to the number of epoxy equivalents (X) of the epoxy resin.

Description

  The present invention relates to an epoxy resin composition and a cured product.

  Epoxy resin compositions are widely used in encapsulants (sealing agents), adhesives, sealing agents, casting materials, etc., because they are excellent in water resistance, chemical resistance, dimensional stability, etc. of cured products. .

  Some epoxy resin compositions have improved ease of curing at low temperatures (low temperature curability) (see, for example, Patent Document 1). However, the epoxy resin composition with improved low-temperature curability has a problem that the hardness of the cured product cannot be made sufficiently excellent.

Japanese Patent No. 3367531

  An object of the present invention is to provide an epoxy resin composition having excellent ease of curing at low temperatures (low temperature curability) and excellent hardness after curing, and also produced using the epoxy resin composition An object of the present invention is to provide a cured product having high hardness.

Such an object is achieved by the present invention described in the following (1) to (14).
(1) an epoxy resin having two or more epoxy groups in the molecule;
A thiol compound having two or more mercapto groups in the molecule;
A solid dispersion type amine adduct-based latent curing accelerator,
The mixing ratio of the epoxy resin to the thiol compound is 0.10 or more in terms of the ratio of the SH equivalent number (X _SH ) of the thiol compound to the epoxy equivalent number (X _EP ) of the epoxy resin (X _SH / X _EP ). An epoxy resin composition characterized by being 0.45 or less.

  Thereby, the epoxy resin composition which is excellent in the ease of hardening at low temperature (low temperature curability) and excellent in hardness after curing can be provided.

  (2) The epoxy resin composition according to (1), wherein the heating time until the degree of cure reaches 65% is 30 seconds or less when heated at 120 ° C.

  Thereby, the low temperature curability of the epoxy resin composition can be made particularly excellent. As a result, a cured product having sufficient hardness can be efficiently produced in a shorter time.

(3) a preliminary curing step performed at a heating temperature of 80 ° C. or higher and 120 ° C. or lower;
The epoxy resin composition according to (1) or (2), which is used in a method having a main curing step performed at a heating temperature of 80 ° C. or higher and 150 ° C. or lower.

  Thereby, the hardness, durability, etc. of the cured product can be made particularly excellent. Further, a cured product excellent in hardness, durability and the like can be efficiently produced in a shorter time.

(4) The epoxy resin composition according to any one of (1) to (3) above, wherein a glass transition temperature (Tg) of a cured product obtained by curing the epoxy resin composition to a curing degree of 90% is 70 ° C. or higher. object.
Thereby, the hardness, durability, etc. of the cured product can be made particularly excellent.

  (5) The thiol compound includes dipentaerythritol hexakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate) and tris- [ The epoxy resin composition according to any one of the above (1) to (4), comprising one or more selected from the group consisting of (3-mercaptopropionyloxy) -ethyl] -isocyanurate.

  Thereby, the low temperature curability of the epoxy resin composition and the hardness of the cured product can be made particularly excellent.

  (6) The epoxy resin composition according to any one of (1) to (5), wherein the epoxy resin composition further contains a phenol resin.

  Thereby, the low temperature curability of the epoxy resin composition and the hardness of the cured product can be made particularly excellent.

  (7) The epoxy resin: The epoxy resin composition according to (6), wherein a content of the phenol resin with respect to 100 parts by weight is 5 parts by weight or more and 10 parts by weight or less.

  Thereby, the sclerosis | hardenability of an epoxy resin composition, the hardness of a hardened | cured material manufactured using an epoxy resin composition, durability, etc. can be made further excellent.

  (8) The epoxy resin composition according to any one of (1) to (7), wherein the epoxy resin composition further contains a borate ester compound.

  Thereby, the viscosity change at the time of storage can be made smaller. Moreover, the permeability at the time of hardening of an epoxy resin composition can be improved.

  (9) The epoxy resin composition according to (8), wherein the content of the boric acid ester compound with respect to 100 parts by weight is 0.1 parts by weight or more and 1.5 parts by weight or less.

  Thereby, the sclerosis | hardenability of an epoxy resin composition, the hardness of a hardened | cured material manufactured using an epoxy resin composition, durability, etc. can be made especially excellent.

  (10) The epoxy resin composition according to any one of (1) to (9), wherein the epoxy resin contains bisphenol A and bisphenol F.

  Thereby, it is low viscosity and can make the viscosity change at the time of storage smaller. Moreover, the curability of the epoxy resin composition can be made particularly excellent.

  (11) The epoxy resin composition according to any one of (1) to (10), wherein the content of the epoxy resin is 50% by weight or more and 85% by weight or less.

  Thereby, the low temperature curability of the epoxy resin composition, the hardness, durability, etc. of the cured product produced using the epoxy resin composition can be made particularly excellent.

  (12) The epoxy resin composition according to any one of (1) to (11), wherein an average particle size of the solid dispersion type amine adduct latent curing accelerator is 2 μm or more and 20 μm or less.

  Thereby, the reactivity of the curing reaction of the epoxy resin composition during heating can be made particularly excellent while the storage stability of the poxy resin composition is sufficiently excellent.

  (13) The epoxy resin composition according to any one of (1) to (12), wherein a content of the solid dispersion type amine adduct-based latent curing accelerator is 5% by weight or more and 30% by weight or less.

  Thereby, the sclerosis | hardenability of an epoxy resin composition, the hardness of a hardened | cured material manufactured using an epoxy resin composition, durability, etc. can be made especially excellent.

(14) A cured product obtained by curing the epoxy resin composition according to any one of (1) to (13).
Thereby, the hardened | cured material of high hardness can be provided.

  According to the present invention, an epoxy resin composition having excellent ease of curing at low temperature (low temperature curability) and excellent hardness after curing is provided, and also produced using the epoxy resin composition Can be provided.

Hereinafter, preferred embodiments of the present invention will be described in detail.
<< Epoxy resin composition >>
First, a preferred embodiment of the epoxy resin composition of the present invention will be described in detail.

  Epoxy resin compositions are widely used in encapsulants (sealing agents), adhesives, sealing agents, casting materials, etc., because they are excellent in water resistance, chemical resistance, dimensional stability, etc. of cured products. .

  Some epoxy resin compositions have improved ease of curing at low temperatures (low temperature curability). However, the conventional epoxy resin composition with improved low-temperature curability has a problem that the hardness of the cured product cannot be made sufficiently excellent.

Therefore, the present inventor has intensively studied for the purpose of solving the above problems, and has arrived at the present invention. That is, the epoxy resin composition of the present invention comprises an epoxy resin having two or more epoxy groups in the molecule, a thiol compound having two or more mercapto groups in the molecule, and a solid dispersion type amine adduct-based latent curing accelerator. The mixing ratio of the epoxy resin and the thiol compound is a ratio (X _SH / X _EP ) of the SH equivalent number (X _SH ) of the thiol compound to the epoxy equivalent number (X _EP ) of the epoxy resin. It is 0.10 or more and 0.45 or less. Thereby, the epoxy resin composition which is excellent in the ease of hardening at low temperature (low temperature curability) and excellent in hardness after curing can be provided. In addition, according to the present invention, the storage stability as a one-pack type (non-mixed type) epoxy resin composition can be excellent, and it is suitable for long-term storage in a state where each component is mixed. Yes.

  On the other hand, when the above conditions are not satisfied, the above excellent effects cannot be obtained.

  For example, when the epoxy resin composition does not contain a thiol compound, or when the content of the thiol compound relative to the epoxy resin is less than the lower limit value even if it contains a thiol compound, the epoxy resin composition The curing reaction of the epoxy resin composition (reaction rate at the initial stage of the reaction), especially the curing reaction at low temperatures cannot be made sufficiently fast, and the low-temperature curability of the epoxy resin composition is sufficiently excellent Can not be.

  Moreover, when the content rate of the thiol compound with respect to an epoxy resin exceeds the said upper limit, the hardness of the hardened | cured material manufactured using an epoxy resin composition cannot be made high enough.

  Moreover, when the epoxy resin composition does not contain a solid dispersion type amine adduct-based latent curing accelerator, the curability of the epoxy resin composition is significantly lowered. In addition, a solid dispersion type amine adduct latent curing accelerator is not used, and instead, other curing accelerators (for example, imidazole curing agents such as 2-phenyl-4-methyl-5-hydroxymethylimidazole, tris When a tertiary amine curing agent such as (dimethylaminomethyl) phenol is used, the storage stability of the epoxy resin composition cannot be made sufficiently excellent, and the epoxy resin composition during storage Unintentional curing reaction of things cannot be sufficiently prevented or suppressed.

<Epoxy resin>
The epoxy resin composition of the present invention contains an epoxy resin having two or more epoxy groups in the molecule. Such an epoxy resin is advantageous in increasing the reactivity of the curing reaction and the hardness after curing among various curable resins. Moreover, such an epoxy resin is an advantageous material from the viewpoints of heat resistance and dimensional accuracy of a cured product among various curable resins.

  Examples of epoxy resins include polyglycidyl ethers obtained by reacting polychlorophenols such as bisphenol A, bisphenol F, bisphenol AD, catechol, and resorcinol, polyhydric alcohols such as glycerin and polyethylene glycol, and epichlorohydrin; -Glycidyl ether ester obtained by reacting a hydroxycarboxylic acid such as hydroxybenzoic acid or β-hydroxynaphthoic acid with epichlorohydrin; by reacting a polycarboxylic acid such as phthalic acid or terephthalic acid with epichlorohydrin Polyglycidyl ester obtained; Epoxidized phenol novolak resin, Epoxidized cresol novolak resin, Epoxidized polyolefin, Cyclic aliphatic epoxy resin, etc. Urethane-modified epoxy resins.

  Among these, those containing bisphenol A and bisphenol F are preferable. Thereby, it is low viscosity and can make the viscosity change at the time of storage smaller. Moreover, the curability of the epoxy resin composition can be made particularly excellent.

  The content of the epoxy resin in the epoxy resin composition is preferably 50% by weight or more and 85% by weight or less, more preferably 55% by weight or more and 80% by weight or less, and 60% by weight or more and 75% by weight or less. More preferably. As a result, the functions of the epoxy resin can be surely exhibited while the functions of other components constituting the epoxy resin (for example, thiol compounds, solid dispersion type amine adduct latent curing accelerators, etc.) are also reliably exhibited. The low temperature curability of the epoxy resin composition and the hardness and durability of the cured product produced using the epoxy resin composition can be made particularly excellent. In addition, when using in combination of 2 or more types of components as an epoxy resin, the sum of the content rate of these components shall be employ | adopted as a content rate of an epoxy resin.

<Thiol compound>
The epoxy resin composition of the present invention contains a thiol compound having two or more mercapto groups in the molecule. Such a thiol compound exhibits functions of lowering the viscosity of the entire composition and uniform curability in the epoxy resin composition of the present invention.

  Examples of the thiol compound include dipentaerythritol hexakis (3-mercaptopropionate), trimethylolpropane tris (thioglycolate), pentaerythritol tetrakis (thioglycolate), ethylene glycol dithioglycolate, trimethylolpropane tris. (Β-thiopropionate), pentaerythritol tetrakis (β-thiopropionate), dipentaerythritol poly (β-thiopropionate) and other thiol compounds obtained by esterification reaction of mercapto organic acid, etc. Alkyl thiol compounds such as 1,4-butanedithiol, 1,6-hexanedithiol, 1,10-decanedithiol; terminal mercapto group-containing polyether; terminal mercapto group-containing polythioether A thiol compound obtained by reaction of an epoxy compound with hydrogen sulfide or the like; a thiol compound having a terminal mercapto group obtained by reaction of a thiol compound with an epoxy compound or the like.

  Among them, dipentaerythritol hexakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate) and tris-[(3-mercaptopropionyloxy) It preferably contains one or more selected from the group consisting of -ethyl] -isocyanurate, and more preferably contains dipentaerythritol hexakis (3-mercaptopropionate). Thereby, the low temperature curability of the epoxy resin composition and the hardness of the cured product can be made particularly excellent.

As described above, in the epoxy resin composition of the present invention, the mixing ratio of the epoxy resin and the thiol compound is such that the ratio of the SH equivalent number (X _SH ) of the thiol compound to the epoxy equivalent number (X _EP ) of the epoxy resin (X _SH ). _SH is / _{X EP)} at 0.10 to _0.45, the value of X SH _{/ X EP} is preferably 0.15 or more 0.35 or less, at 0.20 to 0.30 More preferably. Thereby, the effect by this invention as mentioned above is exhibited more notably.

  The content of the thiol compound in the epoxy resin composition is preferably 5% by weight to 30% by weight, more preferably 8% by weight to 25% by weight, and more preferably 12% by weight to 20% by weight. More preferably. Thereby, the effect by this invention as mentioned above is exhibited more notably. In addition, when using in combination of 2 or more types as a thiol compound, the sum of the content rate of these components shall be employ | adopted as a content rate of a thiol compound.

  In the epoxy resin composition of the present invention, the content of the thiol compound with respect to 100 parts by weight of the epoxy resin is preferably 10 parts by weight or more and 45 parts by weight or less, and 7 parts by weight or more and 40 parts by weight or less. Is more preferably 15 parts by weight or more and 40 parts by weight or less. Thereby, the effect by this invention as mentioned above is exhibited more notably.

<Solid dispersion type amine adduct-based latent curing accelerator>
The epoxy resin composition of the present invention contains a solid dispersion type amine adduct-based latent curing accelerator (hereinafter, also simply referred to as “latent curing accelerator”).

  In the present invention, the solid dispersion type amine adduct-based latent curing accelerator is a solid that is insoluble in an epoxy resin at room temperature (25 ° C.) and is solubilized by heating and functions as a curing accelerator. It refers to the reaction product of a compound. Such a solid dispersion-type amine adduct-based latent curing accelerator is used in the epoxy resin composition of the present invention to prevent unintentional reaction of the epoxy resin during storage, and when necessary, by heating the epoxy resin. It has a function of promoting the curing reaction.

  As an epoxy compound used as a raw material for producing a latent curing accelerator, for example, a reaction between a polyhydric phenol such as bisphenol A, bisphenol F, bisphenol AD, catechol, resorcinol, or a polyhydric alcohol such as glycerin or polyethylene glycol and epichlorohydrin. Polyglycidyl ether obtained by, for example, glycidyl ether ester obtained by reacting hydroxycarboxylic acid such as p-hydroxybenzoic acid and β-hydroxynaphthoic acid with epichlorohydrin; polycarboxylic acid such as phthalic acid and terephthalic acid A polyglycidyl ester obtained by reacting chlorohydrin with epichlorohydrin, etc .; reacting 4,4′-diaminodiphenylmethane, m-aminophenol, etc. with epichlorohydrin Glycidylamine compounds obtained by, for example, polyfunctional epoxy compounds such as epoxidized phenol novolak resin, epoxidized cresol novolak resin, epoxidized polyolefin, and the like such as butyl glycidyl ether, phenyl glycidyl ether, and glycidyl methacrylate. A functional epoxy compound etc. are mentioned.

The amine compound used as a raw material for producing the latent curing accelerator is an amino group (—NH ₂ ) that can undergo an addition reaction with an epoxy group, or one or two of the active hydrogens that the amino group has is substituted with an alkyl group or the like. Any compound having a functional group (ie, primary amine, secondary amine, tertiary amine) may be used. Examples of such amine compounds include aliphatic amines such as diethylenetriamine, triethylenetetramine, n-propylamine, 2-hydroxyethylaminopropylamine, cyclohexylamine, and 4,4′-diamino-dicyclohexylmethane; Aromatic amine compounds such as 4'-diaminodiphenylmethane and 2-methylaniline, 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazoline, 2,4-dimethylimidazoline, piperidine, piperazine And nitrogen-containing heterocyclic compounds such as The amine compound as a raw material for producing the latent curing accelerator includes a urea compound (compound having a partial structure of NC (═O) N).

  Of the amine compounds, tertiary amine is a raw material that provides a latent curing accelerator having particularly excellent curing acceleration. Examples of such compounds include amines such as dimethylaminopropylamine, diethylaminopropylamine, di-n-propylaminopropylamine, dibutylaminopropylamine, dimethylaminoethylamine, diethylaminoethylamine, N-methylpiperazine and the like. Primary amine structure (amino group) with tertiary amine structure in the molecule such as compounds and imidazole compounds such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, etc. Or a secondary amine structure (tertiary amine, 2-dimethylaminoethanol, 1-methyl-2-dimethylaminoethanol, 1-phenoxymethyl-2-dimethylaminoethanol, 2-diethylaminoethanol, 1 Butoxymethyl-2-dimethylaminoethanol, 1- (2-hydroxy-3-phenoxypropyl) -2-methylimidazole, 1- (2-hydroxy-3-phenoxypropyl) -2-ethyl-4-methylimidazole, 1 -(2-hydroxy-3-butoxypropyl) -2-methylimidazole, 1- (2-hydroxy-3-butoxypropyl) -2-ethyl-4-methylimidazole, 1- (2-hydroxy-3-phenoxypropyl) ) -2-Phenylimidazoline, 1- (2-hydroxy-3-butoxypropyl) -2-methylimidazoline, 2- (dimethylaminomethyl) phenol, 2,4,6-tris (dimethylaminomethyl) phenol, N- β-hydroxyethylformoline, 2-dimethylaminoethanethiol, 2- Mercaptopyridine, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 4-mercaptopyridine, N, N-dimethylaminobenzoic acid, N, N-dimethylglycine, nicotinic acid, isonicotinic acid, picolinic acid, N, N- Alcohols having a tertiary amine in the molecule, such as dimethylglycine hydrazide, N, N-dimethylpropionic hydrazide, nicotinic hydrazide, isonicotinic hydrazide, phenols, thiols, carboxylic acids, hydrazides, etc. Can be mentioned.

  In addition, as the solid dispersion type amine adduct-based latent curing accelerator, for example, the surface of the reaction product of the amine compound and the epoxy compound as described above may be treated with an isocyanate compound or an acidic compound. Good.

  Among the solid dispersion-type amine adduct-based latent curing accelerators, commercially available products include, for example, “Fujicure FXR1081” (trade name of T & K Toka Co., Ltd.), “Amicure PN-23” (Ajinomoto Co., Inc.). ) Product name), "Amicure PN-H" (Ajinomoto Co., Ltd. product name), "Amicure MY-24" (Ajinomoto Co., Ltd. product name), "Hardner X-3661S" (AC Co., Ltd.) Product name), "Hardener X-3670S" (ARC Earl Co., Ltd. product name), "Novacure HX-3742" (Asahi Kasei Co., Ltd. product name), "Novacure HX-3721" (Asahi Kasei Co., Ltd. product) Name).

  The average particle size of the solid dispersion type amine adduct-based latent curing accelerator is preferably 2 μm or more and 20 m or less, and more preferably 2 μm or more and 10 μm or less. Thereby, the reactivity of the curing reaction of the epoxy resin composition during heating can be made particularly excellent while the storage stability of the epoxy resin composition is sufficiently excellent. In the present specification, unless otherwise specified, the average particle diameter means a volume-based average particle diameter. The average particle size can be determined, for example, by measurement using a particle size distribution measuring device 1064L (manufactured by SILAS).

  The content of the solid dispersion type amine adduct-based latent curing accelerator in the epoxy resin composition is preferably 5% by weight to 30% by weight, and more preferably 8% by weight to 25% by weight. More preferably, it is 10 weight% or more and 20 weight% or less. Thus, the functions of other components (for example, epoxy resin, thiol compound, etc.) constituting the epoxy resin composition can be achieved while ensuring the functions of the solid dispersion type amine adduct-based latent curing accelerator as described above. Can be exhibited with certainty, and the curability of the epoxy resin composition and the hardness and durability of the cured product produced using the epoxy resin composition can be made particularly excellent. In addition, when using in combination of 2 or more types of components as a solid dispersion type amine adduct type | system | group latent hardening accelerator, as content rate of a solid dispersion type amine adduct type | system | group latent hardening accelerator, the content rate of these components is used. Shall be adopted.

  Further, the content of the solid dispersion type amine adduct latent curing accelerator with respect to 100 parts by weight of the epoxy resin is preferably 10 parts by weight or more and 35 parts by weight or less, and 15 parts by weight or more and 30 parts by weight or less. Is more preferably 18 parts by weight or more and 25 parts by weight or less. Thus, the functions of other components (for example, epoxy resin, thiol compound, etc.) constituting the epoxy resin composition can be achieved while ensuring the functions of the solid dispersion type amine adduct-based latent curing accelerator as described above. Can be exhibited with certainty, and the curability of the epoxy resin composition and the hardness and durability of the cured product produced using the epoxy resin composition can be made particularly excellent.

<Phenolic resin>
The epoxy resin composition of the present invention may contain, for example, a phenol resin in addition to the components described above. Thereby, the low temperature curability of the epoxy resin composition and the hardness of the cured product can be made particularly excellent.

  Examples of the phenol resin include novolak type phenol resins such as phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, resol type phenol resin, allylphenol / formaldehyde resin, 2,2′-diallyl-4,4′-isopropylate. Examples include redene and diphenol.

  Moreover, it is preferable that it is 2 to 10 weight part, and, as for the content rate of the phenol resin with respect to 100 weight part of epoxy resins, it is more preferable that it is 2 to 5 weight part. Thereby, other components constituting the epoxy resin composition (for example, epoxy resin, thiol compound, solid-dispersed amine adduct latent curing accelerator, etc.) while ensuring the functions of the phenol resin as described above are exhibited. ) Can be exhibited with certainty, and the curability of the epoxy resin composition and the hardness and durability of the cured product produced using the epoxy resin composition can be further improved. . In addition, when using in combination of 2 or more types of components as a phenol resin, the sum of the content rate of these components shall be employ | adopted as a content rate of a phenol resin.

  The content of the phenol resin in the epoxy resin composition is preferably 2% by weight or more and 10% by weight or less, and more preferably 2% by weight or more and 5% by weight or less. Thereby, other components constituting the epoxy resin composition (for example, epoxy resin, thiol compound, solid-dispersed amine adduct latent curing accelerator, etc.) while ensuring the functions of the phenol resin as described above are exhibited. ) Can be exhibited with certainty, and the curability of the epoxy resin composition and the hardness and durability of the cured product produced using the epoxy resin composition can be made particularly excellent.

<Boric acid ester compound>
The epoxy resin composition of the present invention may include, for example, a borate ester compound. Thereby, the storage stability of the epoxy resin composition can be made particularly excellent. Moreover, the viscosity change at the time of storage can be made smaller. Moreover, the permeability at the time of hardening of an epoxy resin composition can be improved.

  Examples of boric acid ester compounds include trimethyl borate, triethyl borate, tri-n-propyl borate, triisopropyl borate, tri-n-butyl borate, tripentyl borate, triallyl borate, trihexyl borate, tricyclohexyl borate, and tricyclohexyl borate. Octyl borate, trinonyl borate, tridecyl borate, tridodecyl borate, trihexadecyl borate, trioctadecyl borate, tris (2-ethylhexyloxy) borane, bis (1,4,7,10-tetraoxaundecyl) ( 1,4,7,10,13-pentaoxatetradecyl) (1,4,7-trioxaundecyl) borane, tribenzyl borate, triphenyl borate, tri-o-tolyl borate, tri-m-tolyl borate , Triethanolamine borate and the like.

  Examples of commercially available boric acid ester compounds include “Cure Duct L-07N” (trade name of Shikoku Kasei Kogyo Co., Ltd.).

  Moreover, it is preferable that the content rate of the boric-ester compound with respect to 100 weight part of epoxy resins is 0.1 to 1.5 weight part, and is 0.2 to 1.0 weight part. More preferably, it is 0.3 to 0.7 parts by weight. As a result, other components constituting the epoxy resin composition (for example, epoxy resin, thiol compound, solid-dispersed amine adduct-based latent curing acceleration) while ensuring the functions of the borate ester compound as described above are exhibited. And the like, and the hardness of the cured product produced using the epoxy resin composition, the durability, etc. are particularly excellent. it can. In addition, when using in combination of 2 or more types of components as a borate ester compound, the sum of the content rate of these components shall be employ | adopted as a content rate of a borate ester compound.

  The content of the boric acid ester compound in the epoxy resin composition is preferably 0.05% by weight or more and 1.2% by weight or less, more preferably 0.1% by weight or more and 0.7% by weight or less. Preferably, it is more preferably 0.2% by weight or more and 0.5% by weight or less. As a result, other components constituting the epoxy resin composition (for example, epoxy resin, thiol compound, solid-dispersed amine adduct-based latent curing acceleration) while ensuring the functions of the borate ester compound as described above are exhibited. And the like, and the hardness of the cured product produced using the epoxy resin composition, the durability, etc. are particularly excellent. it can.

<Other ingredients>
The epoxy resin composition of the present invention may contain components other than the above (other components). Examples of such components include epoxy resins, resin components other than phenol resins (for example, resins having only one epoxy group in the molecule), compounds having only one mercapto group in the molecule, various fillers, UV absorbers, anti-aggregation agents, surfactants, various polymerization initiators, various polymerization accelerators, acid crosslinking agents, sensitizers, light stabilizers, luminescent materials, colorants, antifungal agents, antiseptics, antioxidants Etc.

  The content of other components in the epoxy resin composition is preferably 10% by weight or less, and more preferably 3% by weight or less. In addition, when using in combination of 2 or more types of components as another component, the sum of the content rate of these components shall be employ | adopted as the content rate of other components.

  When the epoxy resin composition of the present invention is heated at 120 ° C., the heating time until the degree of cure reaches 65% is preferably 30 seconds or less, more preferably 20 seconds or less. More preferably, it is 2 seconds or less, and most preferably 5 seconds or less. Thereby, the low temperature curability of the epoxy resin composition can be made particularly excellent. As a result, a cured product having sufficient hardness can be efficiently produced in a shorter time.

  In addition, the measurement of a cure degree can be performed using various apparatuses, such as DSC-60 (made by SHIMADZU).

  The epoxy resin composition of the present invention is used in a method having a preliminary curing step performed at a heating temperature of 80 ° C. or higher and 120 ° C. or lower and a main curing step performed at a heating temperature of 80 ° C. or higher and 150 ° C. or lower. Is preferred. Thereby, the hardness, durability, etc. of the cured product can be made particularly excellent. Further, a cured product excellent in hardness, durability and the like can be efficiently produced in a shorter time.

  The heating temperature in the preliminary curing step is preferably 80 ° C. or higher and 120 ° C. or lower, more preferably 90 ° C. or higher and 120 ° C. or lower, and further preferably 100 ° C. or higher and 120 ° C. or lower. Thereby, the effects as described above are more remarkably exhibited.

  The heating time in the preliminary curing step is preferably 5 seconds or longer and 30 seconds or shorter, and more preferably 5 seconds or longer and 20 seconds or shorter. Thereby, the effects as described above are more remarkably exhibited.

  The heating temperature in the main curing step is preferably 80 ° C. or higher and 150 ° C. or lower, more preferably 90 ° C. or higher and 140 ° C. or lower, and still more preferably 90 ° C. or higher and 120 ° C. or lower. Thereby, the effects as described above are more remarkably exhibited.

  The heating time in the main curing step is preferably 1 minute or more and 60 minutes or less, and more preferably 5 minutes or more and 30 minutes or less. Thereby, the effects as described above are more remarkably exhibited.

  In the present invention, the glass transition temperature (Tg) of a cured product obtained by curing the epoxy resin composition to a curing degree of 90% is preferably 70 ° C or higher, more preferably 75 ° C or higher and 120 ° C or lower. Preferably, it is 100 degreeC or more and 120 degrees C or less. Thereby, the hardness, durability, etc. of the cured product can be made particularly excellent.

  The viscosity at 25 ° C. of the epoxy resin composition (viscosity measured using a cone-type viscometer) is not particularly limited, but is preferably 1,000 mPa · s or more and 10,000 mPa · s or less, and preferably 2,000 mPa · s. More preferably, it is s or more and 5,000 mPa · s or less. When the viscosity of the epoxy resin composition is within the above range, the dispensing characteristics can be made particularly excellent. In addition, the measurement of the viscosity of an epoxy resin composition can be performed using a cone-type viscometer, for example, and can be especially performed based on JISZ8809.

  The epoxy resin composition of the present invention may be used for any purpose, but can be suitably applied to, for example, an encapsulant (sealing agent), an adhesive, a sealing agent, a casting material, and the like.

《Hardened product》
Next, the cured product of the present invention will be described.

  The cured product of the present invention is obtained by curing the epoxy resin composition of the present invention as described above. Such a cured product has high hardness and excellent shape stability.

  As mentioned above, although preferred embodiment of this invention was described, this invention is not limited to these.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

[1] Production of epoxy resin composition (Example 1)
Bisphenol A-type F-type mixed epoxy resin (835LV, manufactured by DC Corporation): 100 parts by weight (epoxy equivalent: 170), and Fujicure FXR1081 (T & K Toka as a solid dispersion type amine adduct-based latent curing agent) 22 parts by weight, dipentaerythritol hexakis (3-mercaptopropionate) as a thiol compound: 26 parts by weight (SH equivalent: 130), and cure duct L-07N (borate ester compound) Shikoku Kasei Kogyo Co., Ltd.): An epoxy resin composition was produced by mixing 0.5 parts by weight.

(Examples 2 to 7)
An epoxy resin composition was produced in the same manner as in Example 1 except that the components used as raw materials and the amounts used thereof were as shown in Table 1.

(Comparative Example 1)
An epoxy resin composition was produced in the same manner as in Example 1, except that the thiol compound was not used as a raw material and the amounts of each component used were as shown in Table 1.

(Comparative Example 2)
An epoxy resin composition was produced in the same manner as in Example 1 except that the solid dispersion type amine adduct latent curing accelerator was not used as a raw material, and the amounts of each component used were as shown in Table 1.

(Comparative Examples 3 and 4)
An epoxy resin composition was produced in the same manner as in Example 1 except that the amounts of components used as raw materials were as shown in Table 1.

(Comparative Example 5)
Instead of using a solid dispersion type amine adduct-based latent curing accelerator as a raw material, instead,
Using 2-phenyl-4-methyl-5-hydroxymethylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd.) as a curing accelerator other than the solid dispersion type amine adduct type latent curing accelerator, the amount of each component used is shown in Table 1. An epoxy resin composition was produced in the same manner as in Example 1 except that the composition was shown.

  Table 1 summarizes the compositions of the epoxy resin compositions of the above Examples and Comparative Examples. In the table, 835LV (manufactured by DIC Corporation) as a bisphenol A type F type mixed epoxy resin is indicated as “835LV”, and HP-4032D (manufactured by DIC Corporation) as a naphthalene epoxy resin is indicated. Fuji Cure FXR1081 (manufactured by T & K Toka Co., Ltd.) as a solid dispersion type amine adduct latent curing agent represented by “HP4032D” is denoted as “FXR1081” as a solid dispersion type amine adduct latent curing agent, and HX-3742 ( Asahi Kasei E-Materials Co., Ltd.) is indicated by “HX-3742”, dipentaerythritol hexakis (3-mercaptopropionate) as a thiol compound is indicated by “DPMP”, and pentaerythritol tetrakis (3- Mercaptopropionate) "P", cure duct L-07N (manufactured by Shikoku Kasei Kogyo Co., Ltd.) as a borate ester compound is represented by "L-07N", and MEH-8000H (manufactured by Meiwa Kasei Co., Ltd.) as a phenol resin is "MEH-8000H" And 2-phenyl-4-methyl-5-hydroxymethylimidazole (manufactured by Shikoku Kasei Kogyo Co., Ltd.) as an imidazole-based curing agent was represented by “2P4MHZ”.

Table 1 also shows the viscosity value at 25 ° C. of the epoxy resin composition measured using a cone-type viscometer (manufactured by HAKE, RV-1) in accordance with JIS Z8809. It was. In Table 1, the ratio of the SH equivalent number of the thiol compound to the epoxy equivalent number of the epoxy resin is indicated by (X _SH / X _EP . Further, as the value of the average particle diameter, 1064L (manufactured by CILAS) The value calculated | required by the measurement etc. using) was shown.

[2] Evaluation of epoxy resin composition [2.1] Storage stability The epoxy resin compositions of the respective examples and comparative examples were allowed to stand for 5 days in an environment of temperature: 25 ° C. and humidity: 60% RH. did.

  Then, about each epoxy resin composition, based on JISZ8809, the viscosity in 25 degreeC was measured using the cone-type viscometer (the product made by HAKE, RV-1), and the viscosity from immediately after manufacture (25 degreeC) The amount of change in viscosity was determined and evaluated according to the following criteria. It can be said that the smaller the amount of change in viscosity, the better the storage stability.

A: The amount of change in viscosity is less than 25% of the initial value.
B: The amount of change in viscosity is 25% or more and less than 100% of the initial value.
C: The amount of change in viscosity is 100% or more and less than 200% of the initial value.
D: The amount of change in viscosity is 200% or more of the initial value.
E: The amount of change in viscosity is not measurable (including gelation).

[2.2] Low-temperature curability The epoxy resin compositions of the above Examples and Comparative Examples are allowed to stand in an environment at a temperature of 120 ° C., and the degree of cure required using DSC-60 (manufactured by SHIMADZU) is The time to 65% was obtained and evaluated according to the following criteria. It can be said that the shorter this time, the better the low-temperature curability.

A: The time until the curing degree reaches 65% is less than 5 seconds.
B: The time until the curing degree reaches 65% is 5 seconds or more and less than 10 seconds.
C: The time until the curing degree reaches 65% is 10 seconds or more and less than 20 seconds.
D: The time until the curing degree reaches 65% is 20 seconds or more and less than 30 seconds.
E: Time until the curing degree reaches 65% is 30 seconds or more.

[3] Evaluation of cured product [3.1] Glass transition temperature of cured product Heating temperature: 90 ° C., and cured product obtained by curing to a curing degree of 90%, using DMS-6100 (manufactured by SII). The glass transition temperature (Tg) was determined and evaluated according to the following criteria. It can be said that the higher the glass transition temperature (Tg), the better the hardness, heat resistance, etc.

A: Glass transition temperature (Tg) of hardened | cured material is 100 degreeC or more and 120 degrees C or less.
B: Glass transition temperature (Tg) of hardened | cured material is 80 degreeC or more and less than 100 degreeC.
C: Glass transition temperature (Tg) of hardened | cured material is 50 degreeC or more and less than 80 degreeC.
D: The glass transition temperature (Tg) of the cured product is less than 50 ° C.
These results are summarized in Table 2.

  As is clear from Table 2, excellent results were obtained in the present invention. Moreover, all the hardened | cured material of this invention had sufficient hardness. On the other hand, in the comparative example, a satisfactory result was not obtained.

Claims (14)

An epoxy resin having two or more epoxy groups in the molecule;
A thiol compound having two or more mercapto groups in the molecule;
A solid dispersion type amine adduct-based latent curing accelerator,
The mixing ratio of the epoxy resin to the thiol compound is 0.10 or more in terms of the ratio of the SH equivalent number (X _SH ) of the thiol compound to the epoxy equivalent number (X _EP ) of the epoxy resin (X _SH / X _EP ). An epoxy resin composition characterized by being 0.45 or less.   The epoxy resin composition according to claim 1, wherein when heated at 120 ° C., the heating time until the degree of cure reaches 65% is 30 seconds or less. A preliminary curing step performed at a heating temperature of 80 ° C. or higher and 120 ° C. or lower;
The epoxy resin composition according to claim 1 or 2, which is used in a method having a main curing step performed at a heating temperature of 80 ° C or higher and 150 ° C or lower.   The epoxy resin composition according to any one of claims 1 to 3, wherein a glass transition temperature (Tg) of a cured product obtained by curing the epoxy resin composition to a curing degree of 90% is 70 ° C or higher.   The thiol compounds include dipentaerythritol hexakis (3-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropionate), trimethylolpropane tris (3-mercaptopropionate) and tris-[(3- The epoxy resin composition according to any one of claims 1 to 4, comprising one or more selected from the group consisting of mercaptopropionyloxy) -ethyl] -isocyanurate.   The epoxy resin composition according to any one of claims 1 to 5, wherein the epoxy resin composition further contains a phenol resin.   The epoxy resin composition according to claim 6, wherein the content of the phenol resin with respect to 100 parts by weight of the epoxy resin is 2 parts by weight or more and 10 parts by weight or less.   The epoxy resin composition according to any one of claims 1 to 7, wherein the epoxy resin composition further contains a boric acid ester compound.   The epoxy resin composition according to claim 8, wherein the content of the boric acid ester compound with respect to 100 parts by weight of the epoxy resin is 0.1 parts by weight or more and 1.5 parts by weight or less.   The epoxy resin composition according to any one of claims 1 to 9, wherein the epoxy resin contains bisphenol A and bisphenol F.   The epoxy resin composition according to any one of claims 1 to 10, wherein the content of the epoxy resin is 50 wt% or more and 85 wt% or less.   12. The epoxy resin composition according to claim 1, wherein an average particle diameter of the solid dispersion type amine adduct latent curing accelerator is 2 μm or more and 20 μm or less.   The epoxy resin composition according to any one of claims 1 to 12, wherein a content of the solid dispersion type amine adduct-based latent curing accelerator is 5 wt% or more and 30 wt% or less.   A cured product obtained by curing the epoxy resin composition according to any one of claims 1 to 13.