JP2021187909A - Epoxy resin composition - Google Patents

Abstract

To provide an epoxy resin composition which includes an epoxy resin and an imidazole adduct type hardening accelerator, and has a good pot-life.SOLUTION: An epoxy resin composition is provided, including epoxy resin (A) and an imidazole adduct type hardening accelerator (B), and not including a phenolic hardening agent, and having a chlorine content of 1,350 mass ppm or more.SELECTED DRAWING: None

Description

The present invention relates to an epoxy resin composition.

Epoxy resin is applied to various applications such as fiber reinforced plastics, electronic parts, adhesives, paints, etc. because its cured product has excellent heat resistance, strength, chemical resistance, adhesiveness, etc. ing.
In various applications, a composition containing an epoxy resin (hereinafter referred to as "epoxy resin composition") usually contains a curing agent for curing the composition, and may further contain a curing accelerator [for example,. , Japanese Patent Application Laid-Open No. 2015-083634 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2013-032510 (Patent Document 2)].

Japanese Unexamined Patent Publication No. 2015-083634 Japanese Unexamined Patent Publication No. 2013-032510

The epoxy resin composition may be prepared as a two-component type. An example of a two-component epoxy resin composition comprises a first liquid containing a curing accelerator and a second liquid containing a curing agent, and at least one of the first liquid and the second liquid contains an epoxy resin. It is a thing.

An object of the present invention is to provide an epoxy resin composition which is applicable as the first agent and contains an epoxy resin and an imidazole adduct-type curing accelerator, and has a good pot life.

The present invention provides an epoxy resin composition and a two-component curable epoxy resin composition shown below.
[1] An epoxy resin composition containing an epoxy resin (A) and an imidazole adduct-type curing accelerator (B) and not containing a phenolic curing agent.
An epoxy resin composition having a chlorine content of 1350 mass ppm or more.
[2] An epoxy resin composition containing an epoxy resin (A) and an imidazole adduct-type curing accelerator (B) and not containing a phenolic curing agent.
An epoxy resin composition having a chlorine content of 1450 mass ppm or more in the epoxy resin (A).
[3] The epoxy resin composition according to [1] or [2], which comprises the epoxy resin (A) and the imidazole adduct-type curing accelerator (B).
[4] Any of [1] to [3], wherein the content of the imidazole adduct-type curing accelerator (B) is 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the epoxy resin (A). Epoxy resin composition described in Crab.
[5] The epoxy resin composition according to any one of [1] to [4], wherein the epoxy resin (A) contains an epoxy resin having two epoxy groups in the molecule.
[6] A two-component curable epoxy resin composition comprising a first liquid which is the epoxy resin composition according to any one of [1] to [5] and a second liquid containing a phenolic curing agent.

It is possible to provide an epoxy resin composition containing an epoxy resin and an imidazole adduct-type curing accelerator and not containing a phenol-based curing agent, which has a good pot life.

<Epoxy resin composition>
The epoxy resin composition according to the present invention (hereinafter, also referred to as “epoxy resin composition”) contains an epoxy resin (A) and an imidazole adduct-type curing accelerator (B). The epoxy resin composition does not contain a phenolic curing agent.

Hereinafter, the epoxy resin composition will be described in detail. Unless otherwise specified, the compounds exemplified as the components contained in or may be contained in the epoxy resin composition in the present specification may be used alone or in combination of two or more.

In the present specification, a composition containing an epoxy resin (A), an imidazole adduct-type curing accelerator (B), and a curing agent (C) is also referred to as a "curable epoxy resin composition". The curable epoxy resin composition may be a two-component type. Unless otherwise specified, the compounds exemplified as the components contained in or may be contained in the curable epoxy resin composition in the present specification may be used alone or in combination of two or more.

[1] Epoxy resin (A)
The epoxy resin (A) is not particularly limited as long as it has one or more epoxy groups in the molecule, but is preferable from the viewpoint of curability of the curable epoxy resin composition and heat resistance and strength of the cured product. It contains an epoxy resin having two or more epoxy groups in the molecule, and more preferably contains an epoxy resin having two epoxy groups in the molecule.

Examples of the epoxy resin having two or more epoxy groups in the molecule include, for example.
Obtained by reacting a polyhydric phenol compound such as bisphenol A, bisphenol F, bisphenol AD, bisphenol S, biphenyldiol, naphthalenediol, novolak resin obtained by condensing or cocondensing phenols with aldehydes, and epichlorohydrin. Aromatic glycidyl ether type epoxy resin that can be used;
An aliphatic glycidyl obtained by reacting a polyhydric alcohol compound such as 1,4-butanediol, 1,6-hexanediol, polyethylene glycol, polypropylene glycol, neopentyl glycol, glycerin, pentaerythritol, and sorbitol with epichlorohydrin. Ether type epoxy resin;
A glycidyl ester type epoxy resin that can be obtained by reacting a polybasic acid such as phthalic acid, hexahydrophthalic acid, or dimer acid with epichlorohydrin;
A glycidylamine type epoxy resin obtained by reacting amines such as aniline, toluidine, diaminodiphenylmethane, p-aminophenol, and p-aminocresol with epichlorohydrin;
Olefin compounds having two or more unsaturated bonds in the molecule such as soybean oil and polybutadiene, inden, 4-vinyl-1-cyclohexene, 3-cyclohexene-1-carboxylic acid (3-cyclohexenyl) methyl and the like. Examples thereof include an alicyclic epoxy resin obtained by oxidizing a cyclic olefin compound having two or more unsaturated bonds in a molecule with a peracid (peracetic acid or the like).
The above-exemplified epoxy resin can be an epoxy resin having two epoxy groups in the molecule.

Examples of the aromatic glycidyl ether type epoxy resin having two epoxy groups in the molecule include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin, bisphenol S type epoxy resin, and biphenyldiol type epoxy resin. , Naphthalene diol type epoxy resin can be mentioned.
Examples of the aliphatic glycidyl ether type epoxy resin having two epoxy groups in the molecule include hydrogenated bisphenol A type epoxy resin, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and polyethylene. Examples thereof include glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and neopentyl glycol diglycidyl ether.
Examples of the glycidyl ester type epoxy resin having two epoxy groups in the molecule include phthalic acid diglycidyl ester, hexahydrophthalic acid diglycidyl ester, and dimer acid diglycidyl ester.
Examples of the glycidylamine type epoxy resin having two epoxy groups in the molecule include glycidylaniline and glycidyltoluidine.

The epoxy resin (A) is preferably aromatic from the viewpoints of the viscosity of the epoxy resin, the viscosity of the epoxy resin composition, the viscosity and curability of the curable epoxy resin composition, and the heat resistance and strength of the cured product. It contains a glycidyl ether type epoxy resin, more preferably a bisphenol type epoxy resin, and further preferably a bisphenol A type epoxy resin.

The epoxy resin (A) preferably contains a liquid epoxy resin, and more preferably, when the epoxy resin (A) contains one or more kinds of epoxy resins, the epoxy resin (A) as a whole is liquid. ..
As used herein, the term "liquid" means to exhibit fluidity at 25 ° C. Substances that are "liquid" in the present specification usually show viscosity, and the viscosity is measured by an E-type viscometer in a viscosity range that cannot be measured by a viscometer (EMS viscometer) using an electromagnetic spinning method or an EMS viscometer. The viscosity at 25 ° C. may be 0.0001 Pa · s to 1000 Pa · s and may be 0.001 Pa · s to 500 Pa · s.
When it is "liquid", it includes a state in which one or more components are dispersed in other components.

Examples of the case where the epoxy resin (A) is liquid as a whole include the following cases.
a) When the epoxy resin (A) is made of one kind of liquid epoxy resin b) When the epoxy resin (A) is a mixture of two or more kinds of liquid epoxy resins c) When the epoxy resin (A) is one or more kinds of liquid When the epoxy resin is a mixture of one or more kinds of solid epoxy resins and the mixture is liquid d) When the epoxy resin (A) is a mixture of two or more kinds of solid epoxy resins and the mixture is liquid

Therefore, the epoxy resin (A) may include a solid epoxy resin. As used herein, the term "solid" means a solid at 25 ° C. The solid epoxy resin may be dissolved or dispersed in the liquid epoxy resin. In order to carry out the curing reaction uniformly, it is preferable that the solid epoxy resin is uniformly dissolved.

From the viewpoint of adjusting the viscosities of the epoxy resin composition and the curable epoxy resin composition to a preferable range, the viscosity of the epoxy resin (A) (when two or more kinds of epoxy resins are contained, the two or more kinds of epoxy resins are used. The viscosity as a mixture) is the viscosity at 25 ° C. by an EMS viscometer, preferably 50 Pa · s or less, more preferably 40 Pa · s or less, and further preferably 20 Pa · s or less.
The viscosity of the epoxy resin (A) at 25 ° C. is usually 0.01 Pa · s or more, may be 0.1 Pa · s or more, or may be 1 Pa · s or more.
The viscosity of the epoxy resin (A) is the viscosity at 25 ° C. by an EMS viscometer, preferably 0.01 Pa · s or more and 50 Pa · s or less, more preferably 0.1 Pa · s or more and 40 Pa · s or less, and 1 Pa · s. More than 20 Pa · s or less is more preferable.

As the epoxy resin having two or more epoxy groups in the molecule, only one type may be used, or two or more types may be used in combination.
The combined use of the bisphenol A type epoxy resin and the biphenyl type epoxy resin is preferable because it may be advantageous in achieving both good heat resistance and good tensile properties in the cured product of the curable epoxy resin composition.

The epoxy resin (A) preferably contains an epoxy resin having two epoxy groups in the molecule.
The epoxy resin (A) is selected from the group consisting of an epoxy resin having two epoxy groups in the molecule, an epoxy resin having one epoxy group in the molecule, and an epoxy resin having three or more epoxy groups in the molecule. It may contain one or more epoxy resins.
The content of the epoxy resin having two epoxy groups in the molecule of the epoxy resin (A) is, for example, 50 parts by mass or more in 100 parts by mass of the epoxy resin (A), and the characteristics of the cured product of the epoxy resin composition ( From the viewpoint of heat resistance and / or tensile properties, etc.), it is preferably 60 parts by mass or more, more preferably 70 parts by mass or more, still more preferably 80 parts by mass or more, still more preferably 90 parts by mass. As mentioned above, it may be 100 parts by mass.

The epoxy equivalent of the epoxy resin (A) (in the case of containing two or more kinds of epoxy resins, the epoxy equivalent as a mixture of the two or more kinds of epoxy resins) is the tensile property of the cured product of the curable epoxy resin composition. From the viewpoint of heat resistance, strength and the like, it is preferably 30 g / eq or more and 500 g / eq or less, more preferably 40 g / eq or more and 400 g / eq or less, and further preferably 50 g / eq or more and 300 g / eq or less. Even more preferably, it is 50 g / eq or more and 250 g / eq or less.
The epoxy equivalent of the epoxy resin can be measured according to JIS K 7236.

[2] Imidazole adduct-type curing accelerator (B)
As used herein, the term "curing accelerator" refers to an agent having a function of accelerating a curing reaction. The term "promotion" as used herein includes the case of initiating a curing reaction.
In the present invention, the imidazole adduct-type curing accelerator (B) is used among the curing accelerators. The use of the imidazole adduct-type curing accelerator (B) may be advantageous in achieving both the pot life of the curable epoxy resin composition and the curability (fast curing, etc.). This is because the imidazole adduct-type curing accelerator (B) can effectively initiate and / or accelerate the curing reaction in the presence of the curing agent (C), and the imidazole adduct-type curing accelerator (B) can be used. It is presumed that this is because it generally has a potential and therefore works favorably for extending the pot life of the curable epoxy resin composition.

Further, using the imidazole adduct-type curing accelerator (B) as the curing accelerator is advantageous in enabling the curing reaction at a relatively low temperature, and also improves the storage stability of the curable epoxy resin composition. It is also advantageous for enhancing.
As the imidazole adduct type curing accelerator (B), only one kind may be used, or two or more kinds may be used in combination.

"Potential" means that the product can be stably stored at room temperature (25 ° C.) even in the presence of an epoxy resin or an epoxy resin and a curing agent, while promoting the curing reaction by heat, light, pressure, or the like. A property that can express a function.
The imidazole adduct-type curing accelerator (B) used in the present invention preferably has a property (thermal potential) capable of exhibiting a function of accelerating the curing reaction by heat.

The imidazole adduct-type curing accelerator (B) is a compound in which an adduct is added to the imidazole compound. The addition of the adduct gives the potential. The adduct is, for example, a compound that can be bonded to the N atom of the imidazole ring, preferably the N atom at the 1-position, by reacting with the imidazole compound. The bond is usually a covalent bond.
The adduct is preferably a compound that can impart good potential, and examples thereof include epoxy compounds, isocyanate compounds, (meth) acrylic compounds, and urea compounds.

The imidazole adduct-type curing accelerator (B) is preferably a polymer compound obtained by reacting the imidazole compound with the above adduct.
Further, the adduct may be further made into a solid solution with a phenol resin or the like, or may be surface-treated with an organic acid, a boric acid compound or the like.
The imidazole adduct-type curing accelerator (B) thus produced is usually pulverized to a particle size of about 0.5 to 50 μm and dispersed in an epoxy resin for use.
Since the imidazole adduct-type curing accelerator (B) generally has low solubility in an epoxy resin at room temperature, the imidazole adduct-type curing accelerator (B) mixed with the epoxy resin often exhibits thermal potential.

The imidazole adduct-type curing accelerator (B) is described in known patent documents, for example, JP-A-59-053526, JP-A-60-004524, JP-A-60-072917, JP-A-2005-206744. It can be produced by the methods described in JP-A-06-0731556, JP-A-06-172495, JP-A-2008-214567, JP-A-2014-177525, and the like.

A commercially available product may be used as the imidazole adduct-type curing accelerator (B). The commercially available products of the imidazole ADEKA duct type curing accelerator (B) are all trade names, "Fujicure FXR-1020", "FXR-1030", "FXR-1032", "FXR-1081", and "Fujicure FXR-1020". FXR-1121 "," FXR-1131 "(above, manufactured by T & K TOKA Corporation);" Adeka Hardener EH-5011S "," EH-5046S "(above, manufactured by ADEKA Corporation);" Cure Duct P- 0505 "(manufactured by Shikoku Kasei Kogyo Co., Ltd.);" Amicure PN-23 "," PN-23J "," PN-31 "," PN-31J "," PN-40 "," PN- 40J ”,“ PN-50 ”,“ PN-F ”,“ PN-H ”(above, manufactured by Ajinomoto Fine-Techno Co., Ltd.) and the like.

The epoxy resin composition may contain one or more curing accelerators other than the imidazole adduct-type curing accelerator (B) as long as the effects of the present invention are not impaired.
The other curing accelerator is not particularly limited, and is, for example, a tertiary amine compound and a salt thereof, an imidazole compound (non-adduct type), an imidazolium salt, a phosphorus compound such as triphenylphosphine or a phosphonium salt, and a metal carboxylate. Examples thereof include salts, 2,3-dihydro-1H-pyrrolo [1,2-a] benzimidazole (TBZ) and the like.

From the viewpoint of more effectively exhibiting the above effects, the content of the other curing accelerator in the curing accelerator is preferably 20 parts by mass or less, more preferably 20 parts by mass or less, when the total amount of the curing accelerator is 100 parts by mass. It is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, still more preferably 1 part by mass or less (for example, 0 parts by mass).

The content of the imidazole adduct-type curing accelerator (B) in the epoxy resin composition is, for example, 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the epoxy resin (A). From the viewpoint of enhancing curability, it is preferably 10 parts by mass or more and 50 parts by mass or less, more preferably 10 parts by mass or more and 45 parts by mass or less, and further preferably 10 parts by mass or more and 40 parts by mass or less.

[3] Other compounding components that can be contained in the epoxy resin composition The epoxy resin composition may further contain other compounding components other than the above-mentioned components.
Other compounding components include, for example, rubber particles, inorganic particles (particles composed of a metal such as aluminum and a metal compound such as calcium carbonate and silica), a flame retardant, a surface treatment agent, a mold release agent, an antibacterial agent, and a leveling agent. Examples thereof include defoaming agents, rocking agents, heat stabilizers, light stabilizers, ultraviolet absorbers, colorants, coupling agents, surfactants, metal alkoxides, thermoplastic resins, diluents and the like.
As the other compounding ingredients, only one kind may be used, or two or more kinds may be used in combination.

The addition of the rubber particles makes it possible to improve the toughness of the cured product of the curable epoxy resin composition while maintaining good heat resistance.

Examples of the rubber particles include core-shell type acrylic rubber particles, surface-modified acrylic rubber particles, crosslinked NBR particles, silicone rubber particles, and the like. These rubber particles may be conventionally known.
The average particle size of the rubber particles is, for example, 0.05 μm or more and 1 μm or less, preferably 0.2 μm or more and 0.5 μm or less.
Only one type of rubber particles may be used, or two or more types may be used in combination.

A commercially available product may be used as the rubber particles, or a dispersed product in which the rubber particles are dispersed in an epoxy resin in advance may be used. As commercial products of rubber particles or the dispersed products, all of them are trade names, "Acryset BPA328" (manufactured by Nippon Catalyst Corporation); "Kaneace MX-153", "MX-154", "MX-257". , "Same MX-960" (above, Kaneka Co., Ltd.); "Staphyroid AC" series (Aika Kogyo Co., Ltd.); "Paraloid EXL" series (Dow); "Metabren" (Mitsubishi Chemical Co., Ltd.) ); "XER-91" (manufactured by JSR Corporation); "GENIOPERL P52" (manufactured by Asahi Kasei Wacker Silicone Co., Ltd.) and the like.

The content of the rubber particles is, for example, 1% by mass or more and 50% by mass or less with respect to the entire curable epoxy resin composition, and is preferably 2% by mass or more and 30% by mass from the viewpoint of more effectively exhibiting the above effects. % Or less, more preferably 2% by mass or more and 20% by mass or less.

The epoxy resin composition does not contain a phenolic curing agent (Cf), which is a kind of curing agent (C). In the present specification, the curing agent (C) refers to a compound capable of cross-linking and curing the epoxy resin (A), and the phenolic curing agent (Cf) refers to a compound capable of cross-linking and curing the epoxy resin (A). A compound having two or more phenolic hydroxyl groups in the molecule. Examples of the phenolic curing agent (Cf) include compounds represented by the formula (C-1) described later (hereinafter, also referred to as “compound (C-1)”).

The epoxy resin composition preferably does not contain the curing agent (C). In this case, the epoxy resin composition may contain other compounding components other than the epoxy resin (A), the imidazole adduct-type curing accelerator (B), and the curing agent (C).
The epoxy resin composition more preferably comprises an epoxy resin (A) and an imidazole adduct-type curing accelerator (B).

[4] Chlorine content The epoxy resin composition satisfies either or both of the following (I) and (II) with respect to the chlorine content.
(I) The chlorine content of the epoxy resin composition is 1350 mass ppm (mg / kg) or more.
(II) The chlorine content of the epoxy resin (A) is 1450 mass ppm (mg / kg) or more.

An epoxy resin composition that satisfies either or both of (I) and (II) can have an excellent pot life as compared with an epoxy resin composition that does not satisfy both (I) and (II). The epoxy resin composition preferably satisfies both (I) and (II).
The chlorine content means the total chlorine content according to JIS K 7243-3: 2005, and is measured according to the same standard.

The chlorine content of the epoxy resin composition is preferably 1400 mass ppm or more, more preferably 1500 mass ppm or more, still more preferably 1600 mass ppm or more, and further preferably 1600 mass ppm or more, from the viewpoint of further improving the pot life. It is preferably 1700 mass ppm or more, particularly preferably 2000 mass ppm or more, and most preferably 2200 mass ppm or more (for example, 2500 mass ppm or more).
The chlorine content of the epoxy resin composition is preferably 10000 mass ppm or less, more preferably 8000 mass ppm or less, still more preferably 8000 mass ppm or less, from the viewpoint of suppressing corrosion of the object to which the epoxy resin composition is applied. It is 5000 mass ppm or less, and more preferably 4000 mass ppm or less.
The chlorine content of the epoxy resin composition is preferably 1400 mass ppm or more and 10000 mass ppm or less, more preferably 1500 mass ppm or more and 8000 mass ppm or less, further preferably 1600 mass ppm or more and 5000 mass ppm or less, and 1700 mass ppm or more and 4000 mass ppm or less. It is even more preferable to have a mass of ppm or less, and particularly preferably 2200 mass ppm or more and 4000 mass ppm or less.

The chlorine content of the epoxy resin (A) is preferably 1500 mass ppm or more, more preferably 1600 mass ppm or more, still more preferably 1700 mass ppm or more, and even more preferably, from the viewpoint of further improving the pot life. It is preferably 1800 mass ppm or more, particularly preferably 2000 mass ppm or more, and most preferably 2500 mass ppm or more (for example, 3000 mass ppm or more).
The chlorine content of the epoxy resin (A) is preferably 10,000 mass ppm or less, more preferably 8,000 mass ppm or less, still more preferably, from the viewpoint of suppressing corrosion of the object to which the epoxy resin composition is applied. Is 5000 mass ppm or less, and more preferably 4000 mass ppm or less.
The chlorine content of the epoxy resin (A) is preferably 1500 mass ppm or more and 10000 mass ppm or less, more preferably 1600 mass ppm or more and 8000 mass ppm or less, further preferably 1700 mass ppm or more and 5000 mass ppm or less, and 1800 mass ppm or more and 4000 mass ppm or less. It is even more preferably mass ppm or less, and particularly preferably 2000 mass ppm or more and 4000 mass ppm or less.

[5] Viscosity and Pot Life of Epoxy Resin Composition The epoxy resin composition is preferably liquid. The meaning of "liquid" is as described above.
In the liquid epoxy resin composition, all the components contained therein may be in a dissolved state, or one or more components may be dispersed in other components.

Immediately after the preparation of the liquid epoxy resin composition, the viscosity at 25 ° C. by an E-type viscometer (for example, device name DV2T manufactured by Brooks Field) is preferably 60 Pa · s or less. It is more preferably 50 Pa · s or less, further preferably 45 Pa · s or less, still more preferably 40 Pa · s or less, and particularly preferably 35 Pa · s or less. The viscosity is usually 8 Pa · s or more, may be 10 Pa · s or more, or may be 15 Pa · s or more.
Immediately after the preparation of the liquid epoxy resin composition, the viscosity at 25 ° C. by an E-type viscometer is preferably 8 Pa · s or more and 60 Pa · s or less, preferably 10 Pa · s or more and 50 Pa · s or less. Is more preferable, 15 Pa · s or more and 45 Pa · s or less is further preferable, 15 Pa · s or more and 40 Pa · s or less is still more preferable, and 15 Pa · s or more and 35 Pa · s or less is particularly preferable.

As described above, the epoxy resin composition according to the present invention can have an excellent pot life as compared with the epoxy resin composition which does not satisfy both (I) and (II). The pot life can be evaluated, for example, by the slope of a graph whose horizontal axis is the number of days of storage since the preparation of the epoxy resin composition and the vertical axis is the viscosity of the composition at 25 ° C. by an E-type viscometer. .. It can be said that the smaller this inclination is, the better the pot life is.
More specifically, the pot life is, for example, the following formula:
Viscosity ratio = (viscosity after X days of storage from epoxy resin composition preparation) / (viscosity immediately after epoxy resin composition preparation)
Can be evaluated by. X is an integer of 1 or more. It can be said that the smaller the viscosity ratio, the better the pot life. Each viscosity in the above formula is the viscosity at 25 ° C. by an E-type viscometer. The above storage is carried out at 25 ° C.

The epoxy resin composition according to the present invention has a viscosity ratio of preferably less than 1.2, more preferably 1.1 or less at X = 6 (day). The viscosity ratio may be 1.0 or more. Further, the epoxy resin composition according to the present invention has a viscosity ratio of preferably 1.5 or less, more preferably 1.3 or less, at X = 14 (day). The viscosity ratio may be 1.0 or more.

<Curable epoxy resin composition>
The curable epoxy resin composition according to the present invention contains an epoxy resin (A), an imidazole adduct-type curing accelerator (B), and a curing agent (C).
The curable epoxy resin composition preferably contains a first liquid which is the epoxy resin composition according to the present invention and a second liquid containing a curing agent (C). The curable epoxy resin composition more preferably contains a first liquid which is the epoxy resin composition according to the present invention and a second liquid containing a curing agent (C), and the curing agent (C) is used. Contains a phenolic curing agent (Cf). The curable epoxy resin composition further preferably contains a first liquid which is the epoxy resin composition according to the present invention and a second liquid containing a curing agent (C), and the curing agent (C) is contained. Contains compound (C-1).

The second liquid may contain one kind of curing agent (C) or two or more kinds. The curing agent (C) may contain one kind of phenolic curing agent (Cf), or may contain two or more kinds. The curing agent (C) may contain one kind of compound (C-1) or two or more kinds.

The second liquid can further contain the epoxy resin (A). The second liquid can further contain other compounding components other than the epoxy resin (A) and the curing agent (C). Examples of other compounding ingredients are similar to those described above. As the epoxy resin (A) and other compounding components, only one kind may be used, or two or more kinds may be used in combination.

The compound (C-1) has the following formula (C-1):

で表される化合物である。

It is a compound represented by.

In the above formula (C-1), R ¹ represents a hydrogen atom, a halogen atom, a methoxy group or a hydrocarbon group having 1 to 12 carbon atoms.
Examples of the halogen atom in R ¹ include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
The hydrocarbon group having 1 to 12 carbon atoms in R ¹ includes an aliphatic group (alkyl group, etc.), an alicyclic group group (cycloalkyl group, etc.), an aromatic group, and a combination of an alicyclic group and an alicyclic group. Examples thereof include a hydrocarbon group composed of, and a hydrocarbon group composed of a combination of an aromatic group and an aliphatic group and / or an alicyclic group.
The hydrocarbon group preferably has 1 to 8 carbon atoms. From the viewpoint of the viscosity of the epoxy resin composition, the hydrocarbon group is a methyl group or a 1-phenylethyl group.
R ¹ is preferably a hydrogen atom or a hydrocarbon group, and more preferably a hydrogen atom.

The positional relationship between the two OH groups of the compound (C-1) may be in the ortho position, the meta position, or the para position, but from the viewpoint of reducing the viscosity of the curable epoxy resin composition and the curable epoxy. From the viewpoint of suppressing crystal precipitation in the resin composition, it is preferably in the ortho position or the meta position, and more preferably in the meta position.

The compound (C-1) has a viewpoint of reducing the viscosity of the curable epoxy resin composition, a viewpoint of suppressing crystal precipitation in the curable epoxy resin composition, and dissolution when preparing the curable epoxy resin composition. From the viewpoint of lowering the temperature, a compound having a melting point of 150 ° C. or lower is preferable, and a compound having a melting point of 130 ° C. or lower is more preferable.

Examples of the compound (C-1) having a melting point of 150 ° C. or lower include catechol (1,2-dihydroxybenzene), resorcin (1,3-dihydroxybenzene), 4-fluoro-1,3-dihydroxybenzene, 2-. Chloro-1,3-dihydroxybenzene, 4-chloro-1,3-dihydroxybenzene, 2-methoxy-1,3-dihydroxybenzene, 4-methoxy-1,3-dihydroxybenzene, 5-methoxy-1,3- Dihydroxybenzene, 4-methyl-1,3-dihydroxybenzene, 5-methyl-1,3-dihydroxybenzene, 2-ethyl-1,3-dihydroxybenzene, 4-ethyl-1,3-dihydroxybenzene, 5-ethyl Examples thereof include -1,3-dihydroxybenzene and 4- (1-phenylethyl) -1,3-dihydroxybenzene.
In the curable epoxy resin composition according to one preferred embodiment, compound (C-1) comprises 1,3-dihydroxybenzene.

The inclusion of the compound (C-1) in the curing agent (C) is advantageous in improving the properties (heat resistance and / or tensile properties, etc.) of the cured product of the curable epoxy resin composition.
The second liquid may further contain a compound having three or more phenolic hydroxyl groups. By containing the compound, the properties (heat resistance and / or tensile properties, etc.) of the cured product of the curable epoxy resin composition may be improved.

Examples of the compound having three or more phenolic hydroxyl groups include a compound in which one of the hydrogen atoms directly bonded to the benzene ring of the compound (C-1) is replaced with a hydroxyl group, a phenol resin, a novolak resin and the like.

Further, the second liquid may contain a compound having one phenolic hydroxyl group. Examples of the compound having one phenolic hydroxyl group include phenol, cresol, xylenol, t-butylphenol and the like.

The molar ratio of the phenolic hydroxyl group content to the epoxy group content in the curable epoxy resin composition is, for example, 0.20 or more and 0.75 or less, and the properties of the cured product (heat resistance and / or tensile properties, etc.) can be determined. From the viewpoint of improvement, it is preferably 0.25 or more and 0.67 or less, more preferably 0.3 or more and 0.6 or less, still more preferably 0.35 or more and 0.55 or less, and even more preferably. It is 0.4 or more and 0.5 or less.

The "epoxy group content in the curable epoxy resin composition" refers to the number (number of moles) of epoxy groups contained in the epoxy resin (A) contained in the curable epoxy resin composition.
The "phenolic hydroxyl group content" is the phenolic hydroxyl group content in the curable epoxy resin composition, and refers to the total number of moles of the phenolic hydroxyl group contained in the phenolic compound having the phenolic hydroxyl group.

The curing agent (C) has the following formula (C-2):

で表される化合物（以下、化合物（Ｃ−２）ともいう。）をさらに含んでいてもよい。
硬化剤（Ｃ）は、化合物（Ｃ−２）を１種含んでいてもよいし、２種以上含んでいてもよい。

It may further contain a compound represented by (hereinafter, also referred to as compound (C-2)).
The curing agent (C) may contain one kind of compound (C-2) or two or more kinds.

In the above formula (C-2), R ² represents a hydrogen atom, a halogen atom, a methyl group or a methoxy group.
Examples of the halogen atom in R ² include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.
R ^2, from the viewpoint of the melting point, preferably a hydrogen atom, a methyl group or a methoxy group, more preferably a hydrogen atom.

Incorporating the compound (C-2) into the curable epoxy resin composition may be advantageous in reducing the viscosity of the curable epoxy resin composition.
Further, the inclusion of the compound (C-2) in the curable epoxy resin composition may be advantageous in enhancing the tensile properties in the cured product of the curable epoxy resin composition. At this time, the breaking elongation property can be improved without lowering the heat resistance of the cured product.

In the curable epoxy resin composition according to one preferred embodiment, compound (C-1) contains 1,3-dihydroxybenzene, and the curable epoxy resin composition further contains compound (C-2), and Compound (C-2) contains dihydrocoumarin (R ² : hydrogen atom).

When the curable epoxy resin composition contains the compound (C-2), the content of the compound (C-2) in the curable epoxy resin composition is, for example, 0. It is 1 part by mass or more, preferably 1 part by mass or more, and more preferably 2 parts by mass or more from the viewpoint of more effectively exhibiting the above effect.

If the content of the compound (C-2) in the curable epoxy resin composition is excessively large, the curable epoxy resin composition may be insufficiently cured. Therefore, when the curable epoxy resin composition contains the compound (C-2), the content of the compound (C-2) in the curable epoxy resin composition is preferably 100 parts by mass of the epoxy resin (A). Is 50 parts by mass or less, more preferably 40 parts by mass or less, still more preferably 30 parts by mass or less.

When the curable epoxy resin composition contains the compound (C-2) together with the compound (C-1), the compound (C-1) in the curable epoxy resin composition is considered from the viewpoint of curability of the curable epoxy resin composition. The ratio of the content of the compound (C-2) to the content of the compound (C-2) is preferably 0.20 or more and 0.95 or less, more preferably 0.20 or more and 0.75 or less, still more preferably, in terms of mass ratio. Is 0.20 or more and 0.50 or less.

The curable epoxy resin composition may further contain a curing agent for epoxy resins other than those described above. The other curing agent for epoxy resin may be a conventionally known curing agent.
However, from the viewpoint of the viscosity or pot life of the curable epoxy resin composition and the characteristics of the cured product (heat resistance and / or tensile characteristics, etc.), the content of the curing agent for other epoxy resins in the curing agent (C) is determined. When the total amount of the curing agent (C) is 100 parts by mass, it is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, still more preferably 5 parts by mass or less, still more preferably 1 part. It is less than or equal to parts by mass (for example, 0 parts by mass).

The curable epoxy resin composition is preferably liquid. The meaning of "liquid" is as described above. In the liquid curable epoxy resin composition, all the components contained therein may be in a dissolved state, or one or more components may be dispersed in other components.

The liquid curable epoxy resin composition can have a relatively low viscosity. The relatively low viscosity can improve the productivity and workability of products using the curable epoxy resin composition.
The viscosity of the curable epoxy resin composition is the viscosity at 25 ° C. by an EMS viscometer, preferably 50 Pa · s or less, more preferably 40 Pa · s or less, still more preferably 30 Pa · s or less. Even more preferably, it is 25 Pa · s or less, and particularly preferably 20 Pa · s or less. The viscosity of the curable epoxy resin composition at 25 ° C. is usually 0.01 Pa · s or more, may be 0.1 Pa · s or more, or may be 1 Pa · s or more.
The viscosity of the curable epoxy resin composition is preferably 0.01 Pa · s or more and 50 Pa · s or less, more preferably 0.1 Pa · s or more and 40 Pa · s or less, and 1 Pa · s. It is more preferably s or more and 30 Pa · s or less, further preferably 1 Pa · s or more and 25 Pa · s or less, and particularly preferably 1 Pa · s or more and 20 Pa · s or less.

The curable epoxy resin composition can exhibit good curability. That is, the curable epoxy resin composition can be sufficiently cured in a relatively short thermosetting time and / or at a relatively low temperature.

<Curing product>
The cured product is obtained by curing the above-mentioned curable epoxy resin composition. The cured product can have good heat resistance or even better tensile properties.

The cured product can exhibit a glass transition temperature of, for example, 110 ° C. or higher, 115 ° C. or higher, 120 ° C. or higher, and 125 ° C. or higher.
The cured product has a breaking elongation of, for example, 4.5% or more, further 5.5% or more, and further 6.5% or more in tensile properties conforming to JIS K 7161-1 and JIS K 7161-2. Further, it may be 7.0% or more, and further may be 7.5% or more.

The curable epoxy resin composition and the cured product thereof according to the present invention can be applied to various uses, and can be used, for example, as an adhesive, a resin composition for encapsulating electronic parts, and a resin composition for impregnating fibers. can.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In the examples,% and parts representing the content or the amount used are based on mass unless otherwise specified.

<Examples 1 to 4 and Comparative Examples 1 to 2>
(1) Preparation of Epoxy Resin Composition An epoxy resin composition was prepared by mixing each component shown in Table 1 below in the blending amount shown in Table 1 below. In Table 1, the unit of the blending amount of each component is a mass part. In all Examples and Comparative Examples, the resulting epoxy resin composition was liquid (fluid at 25 ° C.).

The details of each compounding ingredient shown in Table 1 are as follows.
[A] Epoxy resin 1: Liquid epoxy resin manufactured by ADEKA Co., Ltd. Product name "EP-4300" (bisphenol A type epoxy resin, epoxy equivalent: 180-200 g / eq, viscosity: 10.4 Pa · s (25 ° C))
[B] Epoxy resin 2: Liquid epoxy resin manufactured by Kokuto Kagaku, trade name "EPOKUKDO YD-128M" (bisphenol A type epoxy resin, epoxy equivalent: 184-196 g / eq, viscosity: 12-14 Pa · s (25 ° C)) )
[C] Epoxy resin 3: Liquid epoxy resin manufactured by Mitsubishi Chemical Co., Ltd. Product name "jER828" (bisphenol A type epoxy resin, epoxy equivalent: about 190 g / eq, viscosity: about 15 Pa · s (25 ° C.))
[D] Epoxy resin 4: Liquid epoxy resin manufactured by Kokuto Kagaku, trade name "EPOKUKDO YD-127" (bisphenol A type epoxy resin, epoxy equivalent: 180-190 g / eq, viscosity: 8-11 Pa · s (25 ° C)) )
[E] Epoxy resin 5: Liquid epoxy resin manufactured by Kokuto Kagaku, trade name "EPOKUKDO YD-128" (bisphenol A type epoxy resin, epoxy equivalent: 184-194 g / eq, viscosity: 11-15 Pa · s (25 ° C)) )
[F] Epoxy resin 6: Liquid epoxy resin manufactured by ADEKA Co., Ltd. Product name "EP-4300E" (bisphenol A type epoxy resin, epoxy equivalent: 185 g / eq, viscosity: 8 Pa · s (25 ° C.))
[G] Curing Accelerator 1: Imidazole Adduct-type Curing Accelerator manufactured by ADEKA Corporation Product name "ADEKA HANDNER EH-5011S" (potential)

(2) Measurement / Evaluation (2-1) Chlorine content of epoxy resin and epoxy resin composition The chlorine content of epoxy resin and epoxy resin composition was measured according to JIS K 7243-3: 2005, respectively. The results are shown in Table 1.

(2-2) Viscosity and Pot Life of Epoxy Resin Composition About 2 g of epoxy resin composition was added to each of the epoxy resin compositions immediately after preparation of the epoxy resin composition and stored in a constant temperature bath at 25 ° C. for a predetermined period. It was encapsulated in a sample tube together with a 0.7 mm aluminum spherical probe. This test tube was set in an E-type viscometer (device name DV2T manufactured by Brooks Field) set at 25 ° C., and the viscosity of the epoxy resin composition was adjusted under the conditions of a motor rotation speed of 1000 rpm, a measurement time of 2 minutes, and a measurement interval of 30 seconds. It was measured. The results are shown in Table 1. In Table 1, "-" means that the viscosity was not measured during the storage period.

The pot life of the epoxy resin composition is as follows:
Viscosity ratio = (viscosity after X days of storage from epoxy resin composition preparation) / (viscosity immediately after epoxy resin composition preparation)
Can be evaluated by. Table 1 shows the viscosity ratios at X = 6 (day) and X = 14 (day). It can be said that the smaller the viscosity ratio, the better the pot life.

The epoxy resin composition of Comparative Example 1 has a very high viscosity ratio at X = 14 (day) as compared with Examples. The epoxy resin composition of Comparative Example 2 had a high viscosity ratio at X = 9 (day) of about 2, and was inferior in pot life without measuring the viscosity ratio at X = 14 (day).

Claims (6)

An epoxy resin composition containing an epoxy resin (A) and an imidazole adduct-type curing accelerator (B) and not containing a phenolic curing agent.
An epoxy resin composition having a chlorine content of 1350 mass ppm or more. An epoxy resin composition containing an epoxy resin (A) and an imidazole adduct-type curing accelerator (B) and not containing a phenolic curing agent.
An epoxy resin composition having a chlorine content of 1450 mass ppm or more in the epoxy resin (A). The epoxy resin composition according to claim 1 or 2, which comprises the epoxy resin (A) and the imidazole adduct-type curing accelerator (B). The content of the imidazole adduct-type curing accelerator (B) is 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the epoxy resin (A), according to any one of claims 1 to 3. Epoxy resin composition. The epoxy resin composition according to any one of claims 1 to 4, wherein the epoxy resin (A) contains an epoxy resin having two epoxy groups in the molecule. A two-component curable epoxy resin composition comprising a first liquid which is the epoxy resin composition according to any one of claims 1 to 5 and a second liquid containing a phenolic curing agent.