JP2013072012A - One-pack epoxy resin composition, and cured product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a one-pack epoxy resin composition highly compatible in both stability in storage and curability, and its cured product.SOLUTION: This one-pack epoxy resin composition contains epoxy resin that is in a liquid state at 25°C, a curing agent of acid anhydride base, and a curing catalyst. When the one-pack epoxy resin composition is stored for 14 days at 40°C and 60% RH, the bodying up magnification of viscosity at 25°C and 50 rpm measured by using an E type viscometer before and after the storage is 2.9 or less. The cured product is obtained by curing the one-pack epoxy resin composition by heating.

Description

  The present invention relates to a one-part epoxy resin composition and a cured product.

  Epoxy resins have a wide range of insulating materials, paints, adhesives, etc. for electronic and electrical parts because their cured products have excellent performance in terms of electrical properties, mechanical properties, heat resistance, adhesiveness, etc. Used for applications.

  Moreover, in the generally used liquid epoxy resin composition, when an acid anhydride compound is used as a curing agent, it is particularly excellent in insulation and moisture resistance, and is used for electrical parts and the like. Many liquid epoxy resin compositions using these acid anhydrides as curing agents are called so-called two-component epoxy resin compositions in which an epoxy resin component and a curing agent component are uniformly mixed immediately before use. The two-part epoxy resin composition can be cured at room temperature or lower temperature conditions, but the epoxy resin component and the curing agent component are stored separately and the two components are accurately stored immediately before use. Therefore, storage and handling thereof are complicated because it is necessary to weigh and mix uniformly. In addition, the two-component liquid epoxy resin composition has a limited pot life and cannot be premixed in large quantities, so the frequency of blending increases each time it is used, and a reduction in work efficiency is avoided. Absent.

  In order to solve the problems of such a two-part epoxy resin composition, several one-part epoxy resin compositions have been proposed so far. Therefore, examples of latent curing agents include amine adduct type and microcapsule type curing catalysts, and various latent curing agents have been designed (see, for example, Patent Documents 1 and 2).

JP-A-3-296525 JP 2010-053353 A

  Conventionally, when a latent curing agent is used, those having excellent storage stability have low curability, and those having excellent curability have poor storage stability, that is, both have a trade-off relationship. In particular, in the recent globalized society, there is a strong demand for storage stability from the viewpoint of transportation costs and curability from the viewpoint of productivity, and the storage stability and curability of a one-part epoxy resin composition are further increased. There is a need for improvement.

  Then, an object of this invention is to provide the one-component epoxy resin composition which can make storage stability and curability highly compatible, and its hardened | cured material.

Such an object is achieved by the following present inventions (1) to (9).
(1) A one-part epoxy resin composition containing an epoxy resin that is liquid at 25 ° C., an acid anhydride-based curing agent, and a curing catalyst, and the resin composition was stored at 40 ° C. and 60% RH for 14 days. A one-part epoxy resin composition having a viscosity increase ratio of 2.9 or less at 25 ° C. and 50 rpm measured with an E-type viscometer before and after storage.
(2) Gelation time at 150 ° C. of the epoxy resin composition is 300 seconds or less (1
The one-component epoxy resin composition described in 1.).
(3) The one-component epoxy resin composition according to (1) or (2), wherein the curing catalyst is a treatment curing catalyst obtained by heat-treating a mixture containing a microcapsule-type latent curing catalyst and an acid anhydride. object.
(4) The one-component epoxy resin composition according to (3), wherein the temperature of the heat treatment for obtaining the treatment curing catalyst is lower than the melting point of the surface membrane component of the microcapsule-type latent curing catalyst. object.
(5) The mixing ratio of the microcapsule-type latent curing catalyst and the acid anhydride when obtaining the treatment curing catalyst is 1 mass of the acid anhydride with respect to 100 parts by mass of the microcapsule-type latent curing catalyst. One part liquid epoxy resin composition as described in (3) or (4) which is more than 1000 parts by weight.
(6) The one-component epoxy resin composition according to any one of (3) to (5), wherein a melting point of a surface film component of the treatment curing catalyst is 70 ° C. or higher.
(7) The one-component epoxy resin composition according to any one of (3) to (6), wherein the microcapsule-type latent curing catalyst is an imidazole microcapsule-type latent curing catalyst.
(8) (3) thru | or (7) which contains the said process hardening catalyst in the ratio used as 1 mass part or more and 20 mass parts or less as a net quantity of the said microcapsule type | mold latent curing catalyst with respect to 100 mass parts of said epoxy resins. The one-component epoxy resin composition according to any one of 1).
(9) A cured product obtained by curing the one-component epoxy resin composition according to any one of (1) to (8) by heating.

  According to the present invention, it is possible to obtain a one-part epoxy resin composition that can achieve both high storage stability and curability, and a cured product thereof.

  The one-part epoxy resin composition of the present invention is a one-part epoxy resin composition containing an epoxy resin that is liquid at 25 ° C., an acid anhydride-based curing agent, and a curing catalyst. It is a one-component epoxy resin composition excellent in storage stability.

  Here, the storage stability is a viscosity increase at 25 ° C. and 50 rpm measured using an E-type viscometer before and after storage when the resin composition was stored at 40 ° C. and 60% RH% for 14 days. In the one-component epoxy resin composition of the present invention, it is preferable that this thickening factor is 2.9 or less. Exceeding this range is not preferred because the thickened width of the material after storage is so large that it cannot be used. In order that the material after thickening can be used reliably, the thickening factor is more preferably 2.0 or less. Moreover, although it does not specifically limit about the lower limit of thickening magnification, It is preferable that it is 1.0 or more. Below this range, a decrease in viscosity due to moisture absorption is considered, and the physical properties of a cured product obtained by curing the resin composition may be decreased.

The one-component epoxy resin composition of the present invention preferably has a gelation time at 150 ° C. of 300 seconds or less. Storage stability and curability are in a trade-off relationship. For example, if the amount of catalyst is reduced, storage stability can be improved, but curability will be reduced. When the gelation time at 150 ° C. exceeds the above upper limit, the curability is lowered and the heating time at the time of curing is extended, so that the working efficiency is lowered. It is preferable to shorten the gel time from the viewpoint of work efficiency, and it is more preferable that the gel time is 210 seconds or less. Moreover, although it does not specifically limit about the lower limit of gelation time, It is preferable that it is 30 second or more. When the gelation time is less than the lower limit, curing of the resin composition proceeds non-uniformly, and physical properties of the obtained cured product may be reduced. In addition, the measurement of gelation time is "JIS C
It can be measured according to “2105 Test method for solvent-free liquid resin for electrical insulation”.

  In the one-component epoxy resin composition of the present invention, the type and blending ratio of the epoxy resin that is liquid at 25 ° C., the kind and blending ratio of the acid anhydride-based curing agent, and the kind and blending ratio of the curing catalyst are adjusted. Thus, the storage stability and gelation time can be within the preferred ranges described above. Among these, the adjustment of the type and blending ratio of the curing catalyst is particularly important.

  Although it does not specifically limit as an epoxy resin used for the one-component epoxy resin composition of this invention, A liquid epoxy resin is preferable at 25 degreeC. Among the epoxy resins, polyvalent epoxy compounds are more preferable. For example, bisphenol A, bisphenol F, bisphenol AD, bisphenol S, tetramethyl bisphenol A, tetramethyl bisphenol F, tetramethyl bisphenol AD, tetramethyl bisphenol S, tetrabromobisphenol A Bisphenol type epoxy resin obtained by glycidylation of bisphenols such as tetrachlorobisphenol A and tetrafluorobisphenol A; other divalent phenols such as biphenol, dihydroxynaphthalene and 9,9-bis (4-hydroxyphenyl) fluorene Glycidylated epoxy resin; 1,1,1-tris (4-hydroxyphenyl) methane, 4,4- (1- (4- (1- (4-hydroxyphenyl)) Epoxy resin obtained by glycidylation of trisphenols such as 1-methylethyl) phenyl) ethylidene) bisphenol; epoxy resin obtained by glycidylation of tetrakisphenols such as 1,1,2,2, -tetrakis (4-hydroxyphenyl) ethane Phenolic novolac, cresol novolak, bisphenol A novolak, brominated phenol novolak, novolak type epoxy resin obtained by glycidylation of novolak such as brominated bisphenol A novolak, etc .; epoxy resin obtained by glycidylation of polyhydric phenols; glycerin and polyethylene glycol Aliphatic ether type epoxy resin obtained by glycidylation of polyhydric alcohol such as p-oxybenzoic acid, ether ester obtained by glycidylation of hydroxycarboxylic acid such as β-oxynaphthoic acid Type epoxy resin; ester type epoxy resin obtained by glycidylation of polycarboxylic acid such as phthalic acid and terephthalic acid; amine type such as glycidated product of amine compounds such as 4,4-diaminodiphenylmethane and m-aminophenol Examples thereof include glycidyl type epoxy resins such as epoxy resins; and alicyclic epoxides such as 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate. Among these, from the viewpoint of storage stability, an epoxy resin obtained by glycidylating bisphenol A and an epoxy resin obtained by glycidylating bisphenol F are preferable, and an epoxy resin obtained by glycidylating bisphenol A is more preferable.

The acid anhydride used in the one-component epoxy resin composition of the present invention is not particularly limited, and examples thereof include phthalic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methyl nadic anhydride, and hydrogenated methyl nadic. Acid anhydride, methylcyclohexene tetracarboxylic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, benzophenone tetracarboxylic anhydride, dodecenyl succinic anhydride, etc. Is mentioned. These acids may be used alone or in combination of two or more. From the viewpoint of reactivity with the microcapsule-type latent catalyst, the acid anhydride is preferably liquid at 25 ° C, and among them, methyltetrahydrophthalic anhydride and tetrahydrophthalic anhydride are more preferable.

Although it does not specifically limit as a curing catalyst used for the one-component epoxy resin composition of this invention, What is used with the conventional epoxy resin composition is applicable. Among these, a latent curing catalyst that does not react with an epoxy resin at room temperature but dissolves by heating and functions as a curing accelerator is preferable. Examples of latent curing catalysts include solid imidazole compounds, dicyandiamide, amine-epoxy adduct compounds, and imidazole-epoxy adduct compounds. From the viewpoint of storage stability, the surface of imidazole compounds and dicyandiamide is encapsulated. A microcapsule-type latent curing catalyst is more preferred. Specific compounds include NOVACURE HX-3742, HX-3721, HX-3722, HX-3088, HX-3741, HX-392HP, and HX-3941HP manufactured by Asahi Kasei E-Materials Corporation, which are commercially available products. Can be used alone or in combination. Among these, from the viewpoint of curability and storage stability, an imidazole microcapsule-type latent curing catalyst is particularly preferable. Specific examples of the compound include NOVACURE HX-3742, HX-3722, and HX-3088 manufactured by Asahi Kasei E-materials.

  The microcapsule-type latent curing catalyst may melt on the surface during long-term storage, and may react with the epoxy resin. Therefore, if the melting point of the surface is increased, storage stability is expected to improve. it can. From such a point of view, the curing catalyst used in the one-part epoxy resin composition of the present invention is a heat treatment of a mixture containing a microcapsule-type latent curing catalyst and an acid anhydride, thereby melting the surface membrane. It is more preferable to use a treatment curing catalyst having an improved slag. By using such a treatment curing catalyst, it is possible to obtain a one-component epoxy resin composition that can achieve both high storage stability and curability. In addition, as an acid anhydride which heat-processes with a microcapsule-type latent curing catalyst, the compound similar to the acid anhydride used for the one-component epoxy resin composition mentioned above can be used.

In addition, the surface membrane component of the microcapsule type latent curing catalyst is not particularly limited, but the treatment that increases the melting point of the surface membrane by heat-treating the mixture containing the microcapsule type latent curing catalyst and the acid anhydride. When a curing catalyst is used for the resin composition, a compound having a functional group capable of reacting with an acid anhydride is preferable. For example, a compound having at least one of a functional group such as an epoxy group, a hydroxyl group, an amino group, an isocyanate group, and a urethane bond can be given. In consideration of the reactivity between the surface membrane and the acid anhydride, a urethane compound is particularly preferable.
Examples of the compound having an epoxy group include a monoepoxy compound and a polyvalent epoxy compound. Examples of the compound having a hydroxyl group include cresols such as phenol, o-cresol, m-cresol, and p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, An aromatic compound having a hydroxyl group such as xylenol such as 3,4-xylenol and 3,5-xylenol, and a phenol novolac resin obtained by reacting an aromatic compound having such a hydroxyl group with an aldehyde. Examples of the compound having an amino group include an aromatic amine compound, a compound having a primary amino group and / or a secondary amino group and no tertiary amino group, and a compound having a tertiary amino group and an active hydrogen group. Etc. Examples of the compound having an isocyanate group include ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, ethylene diisocyanate, propylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylene diisocyanate, 1,5-naphthalene diisocyanate, and the like. Examples of the compound having a urethane bond include a urethane compound obtained by reacting the above-mentioned compound having an isocyanate group and a compound having a hydroxyl group. Here, the compound having a hydroxyl group that reacts with a compound having an isocyanate group may be a compound in which an epoxy group contained in the amine adduct of the core is ring-opened. Among these surface membrane components, a urethane compound is more preferable in consideration of the reactivity between the surface membrane and the acid anhydride.

The heat treatment temperature of the mixture containing the microcapsule type latent curing catalyst and the acid anhydride is not particularly limited, but the heat treatment is preferably performed at a temperature lower than the melting point of the surface membrane component of the microcapsule type latent curing catalyst. If the heat treatment is performed at a temperature equal to or higher than the melting point of the surface membrane component, the surface membrane may melt, and the potential of the curing catalyst may be lost. The reaction of the surface membrane component and the acid anhydride raises the melting point of the surface membrane, but when the processing temperature is low, the surface membrane component and the acid anhydride cannot react and the treatment effect may not be obtained. Accordingly, the heat treatment temperature is preferably 30 ° C. or more and 60 ° C. or less, and more preferably 35 ° C. or more and 50 ° C. or less.

  The acid anhydride used for the treatment curing catalyst is preferably in the range of 1 part by mass to 1000 parts by mass with respect to 100 parts by mass of the microcapsule type latent curing catalyst. If the amount of the acid anhydride is less than this range, the treatment effect cannot be obtained and the storage stability may not be improved. On the other hand, if it exceeds this range, the storage stability is improved, but the curability may be lowered. In order to achieve both storage stability and curability at a high level, the amount of acid anhydride with respect to 100 parts by mass of the microcapsule-type latent curing catalyst is preferably 5 parts by mass or more and 500 parts by mass or less. More preferably, it is at least 300 parts by mass.

  The higher the melting point of the surface curing component of the treatment curing catalyst, the better the storage stability, but the melting point is preferably 70 ° C. or higher. If the melting point is lower than this range, the storage stability may not be improved. In order to improve the storage stability, the temperature is more preferably 72 ° C or higher.

  If the melting point of the surface film component of the treatment curing catalyst is higher than the melting point of the surface film component of the microcapsule type latent curing catalyst used, the storage stability is improved. If the rise of the melting point is small, the effect of improving the storage stability may not be obtained, so the melting point is preferably 3 ° C. or higher. The increasing range of the melting point can be adjusted by the kind and amount of the surface layer component of the microcapsule type latent curing catalyst, the kind and amount of the acid anhydride, the heat treatment temperature and the heat treatment time, and the like.

  In the one-component epoxy resin composition of the present invention, the amount of the treatment curing catalyst when the treatment curing catalyst is used as the curing catalyst is the net amount of the microcapsule-type latent curing catalyst with respect to 100 parts by mass of the epoxy resin. It is preferable to contain in the ratio which becomes 1 to 20 mass parts. If the amount of catalyst is less than this range, curability may be significantly reduced. On the other hand, if it exceeds this range, sufficient curability can be obtained, but storage stability may be lowered. In order to achieve both high storage stability and curability, it is particularly preferable to include the net blending amount of the microcapsule type latent curing catalyst at a ratio of 2 parts by mass or more and 10 parts by mass or less.

  The one-part epoxy resin composition of the present invention includes a filler, a leveling agent, a lubricant, an anti-settling agent, a dispersant, a flame retardant, an adhesion promoter, and a pigment within a range that does not impair the effects of the present invention. Other additives may be added.

  The one-component epoxy resin composition of the present invention can be prepared by mixing each raw material component sufficiently uniformly using a mixer or the like, and further kneading using a kneader such as a kneader or roll. .

  Next, the cured product of the present invention will be described. The cured product of the present invention can be obtained by curing the one-component epoxy resin composition of the present invention by heating. More specifically, a cured product can be obtained by heating the one-component epoxy resin composition of the present invention at 80 to 200 ° C. for 10 minutes to 10 hours.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these Examples.

The raw materials used in Reference Examples, Comparative Reference Examples, Examples and Comparative Examples are as follows.
(1) Microcapsule type latent curing catalyst 1: “Novacure HX-3742” manufactured by Asahi Kasei E-materials (imidazole microcapsule, surface membrane component is urethane compound)
(2) Liquid epoxy resin 1: “DER-331J” (bisphenol A type epoxy resin) manufactured by Dow Chemical Japan
(3) Acid anhydride curing agent: “HN-5500” (3- or 4-methyl-hexahydrophthalic anhydride) manufactured by Hitachi Chemical Co., Ltd.

(Production of curing catalyst)
(Reference Example 1)
3 g of acid anhydride 1 and 3 g of microcapsule-type latent curing catalyst 1 were placed in 20 mL of a wide-mouthed polyvin and heat-treated at 40 ° C. for 3 days to obtain 6 g of treated curing catalyst 1.

(Reference Example 2)
20 mL of wide mouthed polybin is charged with 3 g of acid anhydride 1, 3 g of liquid epoxy resin 1 and 3 g of microcapsule type latent curing catalyst 1 and heat-treated at 40 ° C. for 3 days to obtain 9 g of treated curing catalyst 2 It was.

(Reference Example 3)
6g of the treatment curing catalyst 3 was obtained in the same manner as in Reference Example 1 except that the heat treatment condition was changed to 60 ° C for 1 day.

(Reference Example 4)
33 g of the treated curing catalyst 4 was obtained in the same manner as in Reference Example 1 except that the amount of the acid anhydride 1 was changed to 30 g.

(Comparative Reference Example 1)
The microcapsule-type latent curing catalyst 1 was used as it was without heat treatment.

(Comparative Reference Example 2)
3 g of the microcapsule-type latent curing catalyst 1 was placed in 20 mL of a wide-mouthed polyvin and heat-treated at 40 ° C. for 3 days to obtain 3 g of a treated curing catalyst 5.

(Characteristic evaluation as curing catalyst)
The melting points of the curing catalysts prepared in Reference Examples 1 to 4 and Comparative Reference Examples 1 and 2 were evaluated by the following methods. The evaluation results are shown in Table 1.

(Melting point)
About the curing catalyst, melting | fusing point was measured using the differential scanning calorimeter of Seiko Instruments Inc. DSC6100, temperature rising rate 10 degree-C / min, measurement temperature 30 degreeC-250 degreeC, and nitrogen atmosphere.

(Production of one-pack type epoxy resin composition)
(Examples 1-6, Comparative Examples 1 and 2)
The liquid epoxy resin 1, acid anhydride 1, and each curing catalyst prepared or prepared in Reference Examples 1 to 4 and Comparative Reference Examples 1 and 2 were blended in the proportions shown in Table 2, and three-one motor (manufactured by Shinto Kagaku Co., Ltd.). , BL1200Ft) and mixed uniformly for 5 minutes to obtain a one-pack type epoxy resin composition.

(Characteristic evaluation as a one-pack type epoxy resin composition)
The curability and storage stability of the epoxy resin compositions prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were evaluated by the methods shown below. The evaluation results are shown in Table 2.

(Curable)
As a parameter indicating the curability of the one-part epoxy resin composition, the gel on a hot plate at 150 ° C. is used using “gelation time” described in “JIS C 2105 Test method for solvent-free liquid resin for electrical insulation”. The conversion time was measured.

(Storage stability)
As parameters indicating the storage stability of the one-pack type epoxy resin composition, the viscosity immediately after production of this composition (V ₀ ) and the viscosity after being left in an atmosphere of 40 ° C./60% RH for 14 days (V ₁₄ ) The ratio was used.
Storage stability (viscosity change rate) = V ₁₄ / V ₀ (1)
However, the viscosity was measured using an E-type viscometer (manufactured by Toki Sangyo), the rotor model was a 3 ° cone, the viscosity measurement temperature was 25 ° C., and the cone rotation speed was 50 rpm.

The treatment curing catalysts 1 to 4 produced in Reference Examples 1 to 4 are treatment curing catalysts, and the melting points of the surface films are all from the melting point of the surface film of the microcapsule-type latent curing catalyst 1 before the heat treatment. Was also higher by 7 ° C. or more and more than 70 ° C. Moreover, Examples 1-6 which are the one-component epoxy resin compositions produced using these process hardening catalysts are ones using the microcapsule type latent curing catalyst 1 before the heat treatment of Comparative Reference Example 1 as it is. Comparative Example 2 which is a one-part epoxy resin composition using a treatment curing catalyst 5 obtained by heating only the microcapsule type latent curing catalyst 1 of Comparative Example 1 and Comparative Reference Example 2 which are liquid epoxy resin compositions In comparison, although the gelation time was comparable, the storage stability was good. Therefore, it was confirmed that by using the treatment curing catalyst of the present invention, a one-part epoxy resin composition having a high level of storage stability and curability can be obtained.

According to the present invention, it is possible to obtain a one-part epoxy resin composition and a cured product thereof that can achieve both storage stability and curability at a high level, and therefore exports that require particularly long-term storage stability. Conductive materials for electronic and electrical parts, anisotropic conductive materials, insulating materials, thermal conductive materials, sealing materials, coating materials, paints, adhesives, bonding pastes, bonding films, prepregs for circuit boards, etc. Can be suitably used.

Claims (9)

  A one-part epoxy resin composition containing an epoxy resin that is liquid at 25 ° C., an acid anhydride-based curing agent, and a curing catalyst, when the resin composition is stored at 40 ° C. and 60% RH for 14 days, A one-component epoxy resin composition having a viscosity increasing ratio of 2.9 or less at 25 ° C. and 50 rpm measured with an E-type viscometer before and after storage.   The one-component epoxy resin composition according to claim 1, wherein the gelation time at 150 ° C of the epoxy resin composition is 300 seconds or less.   The one-pack epoxy resin composition according to claim 1 or 2, wherein the curing catalyst is a treatment curing catalyst obtained by heat-treating a mixture containing a microcapsule-type latent curing catalyst and an acid anhydride.   The one-component epoxy resin composition according to claim 3, wherein a temperature of the heat treatment for obtaining the treatment curing catalyst is lower than a melting point of a surface film component of the microcapsule type latent curing catalyst.   The mixing ratio of the microcapsule-type latent curing catalyst and the acid anhydride when obtaining the treatment curing catalyst is 1 part by mass or more of the acid anhydride with respect to 100 parts by mass of the microcapsule-type latent curing catalyst, The one-component epoxy resin composition according to claim 3 or 4, which is 1000 parts by mass or less.   The one-component epoxy resin composition according to any one of claims 3 to 5, wherein a melting point of a surface film component of the treatment curing catalyst is 70 ° C or higher.   The one-component epoxy resin composition according to any one of claims 3 to 6, wherein the microcapsule-type latent curing catalyst is an imidazole microcapsule-type latent curing catalyst.   8. The method according to claim 3, wherein the treatment curing catalyst is included in a ratio of 1 part by mass or more and 20 parts by mass or less as a net amount of the microcapsule type latent curing catalyst with respect to 100 parts by mass of the epoxy resin. The one-component epoxy resin composition according to Item. A cured product obtained by curing the one-component epoxy resin composition according to any one of claims 1 to 8 by heating.