JP2015101633A - Epoxy resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an epoxy resin composition which uses a polythiol compound as a curing agent, has a high glass transition point, and is quickly cured.SOLUTION: An epoxy resin composition comprises (A)-(D) components, (B) component present dispersed in (A) component. The (A) component is: epoxy resin not comprising (B) component and liquid at 25°C, the (B) component is: a compound solid at 25°C, having a triazine skeleton in a molecule and 3 or more epoxy groups, the (C) component is: a polythiol compound liquid at 25°C, and the (D) component is: curing agent.

Description

The present invention relates to an epoxy resin composition having a high glass transition point and fast curing.

Patent Document 1 describes an invention of an epoxy resin composition containing an epoxy resin, a polythiol compound, and an amine adduct curing accelerator. However, the pot life is very short. Although not described in Patent Document 1, a cured product of an epoxy resin composition using a polythiol compound as a curing agent has a lower glass transition point than an epoxy resin composition using another curing agent. There is a tendency to become. In a reliability test (in an atmosphere of 80 ° C. or an atmosphere of 85 ° C. × 85% RH), the glass transition point is always exceeded and there is a risk that strength will be reduced.

JP-A-6-211969

Conventionally, it has been difficult to increase the glass transition point of an epoxy resin using a polythiol compound as a curing agent.

As a result of intensive studies to achieve the above object, the present inventors have completed the present invention relating to an epoxy resin composition that increases the glass transition point.

The gist of the present invention will be described next. The first embodiment of the present invention is an epoxy resin composition that includes the components (A) to (D), and the component (B) is present dispersed in the component (A).
Component (A): Epoxy resin that is liquid at 25 ° C. without component (B) Component: Compound (C) that is solid at 25 ° C. and has a triazine skeleton in the molecule and has 3 or more epoxy groups (C) Component: 25 Polythiol compound (D) component liquid at ℃: Curing agent

2nd embodiment of this invention is an epoxy resin composition as described in 1st embodiment whose (B) component is a compound of Formula 1.

A third embodiment of the present invention is the epoxy resin composition according to any one of the first and second embodiments, wherein the component (D) contains an amine adduct type curing agent.

The fourth embodiment of the present invention is the epoxy resin according to any one of the first to third embodiments, which contains tributyl borate and / or 2,4,6-trimethoxyboroxine as component (E). It is a composition.

The present invention enables an epoxy resin composition having a high glass transition point of a cured product and capable of rapid curing but good storage stability.

Details of the present invention will be described below. The component (A) that can be used in the present invention is an epoxy resin that does not contain the following component (B). A compound having two or more epoxy groups in one molecule is preferable. One type or a mixture of two or more types may be used. If it is liquid at 25 ° C, use a solid epoxy resin dissolved at 25 ° C in a liquid epoxy resin at 25 ° C. Also good. The chlorine ion concentration is preferably such that the total chlorine content is 1000 ppm or less, more preferably 700 ppm or less. Storage stability can be maintained as it is 1000 ppm or less.

Specific examples of the component (A) include those obtained by condensation of epichlorohydrin with polyhydric phenols such as bisphenols and polyhydric alcohols, such as bisphenol A type, brominated bisphenol A type, hydrogenated bisphenol A type, Glycidyl ethers such as bisphenol F type, bisphenol S type, bisphenol AF type, biphenyl type, naphthalene type, fluorene type, novolak type, phenol novolak type, orthocresol novolak type, tris (hydroxyphenyl) methane type, tetraphenylolethane type A type epoxy resin can be exemplified. Other glycidyl ester type epoxy resins obtained by condensation of epichlorohydrin with carboxylic acids such as phthalic acid derivatives and fatty acids, glycidyl amine type epoxy resins obtained by reaction of epichlorohydrin with amines, cyanuric acids, hydantoins, and various Examples thereof include, but are not limited to, epoxy resins modified by the method.

Examples of commercially available epoxy resins include 827 and 828EL manufactured by Mitsubishi Chemical Corporation, and EPICLON 830 and EXA-835LV manufactured by Dainippon Ink Industries, Ltd. Examples include Etoto YD-128 and YDF-170 manufactured by Toto Kasei Co., Ltd., but are not limited thereto. Considering the price, an epoxy resin having a bisphenol A skeleton and a bisphenol F skeleton is preferable.

The component (B) that can be used in the present invention is a compound that is solid at 25 ° C., has a triazine skeleton in the molecule, and has 3 or more epoxy groups. In particular, the epoxy resin described in Formula 1 is preferable. In view of the influence on storage stability, the component (B) preferably has a high purity, and the chlorine ion concentration is preferably 1000 ppm or less, more preferably 700 ppm or less. Storage stability can be maintained as it is 1000 ppm or less.

In the present invention, the component (B) can be used by being uniformly dispersed in the component (A). Dispersion means kneading the pulverized component (B) into the component (A), or pulverizing the component (B) in the component (A). When pulverizing using a pulverizer or a high-speed stirrer, kneading or pulverization in the component (A) is possible using a twin-screw stirrer, high-speed stirrer, triple roll mill or the like. However, the present invention is not limited to these devices. (B) As an average particle diameter of a component, it is preferable that it is 100 micrometers or less. The component (B) can be dissolved in the heated component (A), but when cooled, the component (B) precipitates, and the deposited component (B) is in the form of a lump having a large average particle size and is uniformly dispersed. It will not be in a state. Furthermore, it is known from the structure of the triazine (isocyanuric acid) skeleton contained in the component (B) that the glass transition point, which is a physical property of the cured product, is increased. However, an epoxy resin having a triazine skeleton other than the component (B) cannot increase the glass transition point.

(B) It is preferable that a component is 50 mass% or less in the whole epoxy resin. When it is 50% by mass or less, thixotropy can be suppressed and fluidity can be maintained, and storage stability can be maintained.

The component (C) that can be used in the present invention is a polythiol compound that is liquid at 25 ° C. A compound having 2 to 6 thiol groups in the molecule is preferable. A compound having one thiol group in the molecule is also known, but it is difficult to use because it does not increase in molecular weight even when reacted. Specific polythiol compounds include tris-[(3-mercaptoproionyloxy) -ethyl] -isocyanurate, pentaerythritol tetrakis (3-mercaptopropionate), dipentaerythritol hexakis (3-mercaptopropio). Acid), trimethylolpropane tris (3-mercaptopropionate), trimethylolpropane tristhioglycolate, pentaerythritol tetrakisthioglycolate, and the like, but are not limited thereto. Specific products include, but are not limited to, TEMPIC, PEMP, DPMP, TMMP and the like of SC Organic Chemical Co., Ltd.

(C) It is preferable that 10-70 mass parts of (C) component is contained with respect to 100 mass parts of total epoxy resins. When the component (C) is more than 10 parts by mass, the curability is good. On the other hand, when the component (C) is less than 70 parts by mass, the storage stability can be maintained.

The component (D) that can be used in the present invention is a curing agent that cures the component (A) and the component (B), and a curing agent that promotes the reaction between the epoxy resin and the component (C). Specific examples of the curing agent include polyamine compounds (including dicyandiamide and hydrazide compounds), phenol compounds, polythiol compounds, acid anhydrides, and the like, and many are liquid at room temperature. In order to promote the reactivity of the curing agent, a tertiary amine compound or the like may be used as a curing accelerator. Curing accelerators are generally solid at room temperature, such as compounds having a solid imidazole skeleton or fine powder obtained by pulverizing an epoxy adduct compound in which a tertiary amine is added to an epoxy resin to stop the reaction in the middle Is used. Examples of commercially available epoxy adduct compounds include the Amicure series manufactured by Ajinomoto Fine Techno Co., Ltd., the Fujicure series manufactured by T & K TOKA Corporation, and the NovaCure series manufactured by Asahi Kasei Chemicals Corporation. Further, organic phosphorus compounds, organic amine compounds, imidazole derivative compounds, and the like are known as accelerators that are liquid at room temperature. In some cases, a curing accelerator can be used as a curing agent.

As for the addition amount of (D) component with respect to a total of 100 mass parts of an epoxy resin, 1-30 mass parts is preferable. When it is more than 1 part by mass, the curability is expressed, and when it is less than 30 parts by mass, the storage stability can be maintained.

In the present invention, a filler can be added, and the filler is classified into an inorganic filler and an organic filler. Examples of the inorganic filler include, but are not limited to, alumina powder, calcium carbonate powder, talc powder, and silica powder. By adding a filler, viscosity and thixotropy can be controlled and strength can be improved. Although there are no particular limitations on the powder characteristics such as the average particle diameter and shape, the average particle diameter is preferably 0.001 to 50 μm in consideration of ease of dispersion in the epoxy resin and nozzle clogging. Moreover, although addition amount can be adjusted suitably, it is preferable that it is 0.1-50 mass parts with respect to 100 mass parts of epoxy resin compositions.

In the epoxy resin composition of the present invention, a colorant such as a pigment and a dye, a metal powder, calcium carbonate, fumed silica, an inorganic filler such as aluminum hydroxide, etc. An appropriate amount of additives such as an organic filler, a flame retardant, a plasticizer, an antioxidant, an antifoaming agent, a silane coupling agent, a leveling agent, and a rheology control agent may be blended. By these additions, a composition excellent in resin strength, adhesive strength, workability, storage stability and the like and a cured product thereof can be obtained.

EXAMPLES Next, although an Example is given and this invention is demonstrated further in detail, this invention is not limited only to these Examples. (Hereinafter, the epoxy resin composition is referred to as a composition.)

In order to prepare the composition, the following components were prepared.
(A) component: (B) component-free epoxy resin / bisphenol A-type and F-type mixed epoxy resin that is liquid at 25 ° C. (EXA-835LV, manufactured by Dainippon Ink Industries, Ltd.)
Component (B): a compound which is solid at 25 ° C. and has a triazine skeleton in the molecule and has 3 or more epoxy groups. Triglycidyl high-purity isocyanurate (TEPIC-S manufactured by Nissan Chemical Industries, Ltd.)
Component (B ′): Epoxy resin other than component (B) / Epoxy-modified triglycidyl isocyanurate (TEPIC-PAS B26, manufactured by Nissan Chemical Industries, Ltd.)
1,3-bis (oxiranylmethyl) -5-methyl-1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione (MeDGIC Shikoku Kasei Kogyo Co., Ltd.)
1,3-diallyl-5- (2,3-epoxypropan-1-yl) -1,3,5-triazine-2,4,6-trione (DA-MGIC, manufactured by Shikoku Chemicals)
1-allyl-3,5-bis (2,3-epoxypropan-1-yl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione (MA-DGIC Shikoku (Made by Kasei Kogyo Co., Ltd.)
Acrylic acid 2- (3,5-bisoxiranylmethyl-2,4,6-trioxy [1,3,5] triazin-1-yl) -ethyl ester (AcDGIC Shikoku Kasei Kogyo Co., Ltd.)
Component (C): Polythiol compound / pentaerythritol tetrakis (3-mercaptopropionate) in liquid form at 25 ° C. (manufactured by PEMP SC Organic Chemical Co., Ltd.)
Component (D): amine adduct type curing agent / epoxy resin curing agent (Amicure MY-24 Ajinomoto Fine Techno Co., Ltd.)
Inhibitor / Tributyl borate (reagent)
・ 2,4,6-Trimethoxyboroxine (reagent)
・ 2,2′-oxybis [5,5-dimethyl-1,3,2-dioxaborinane] (L-07N manufactured by Shikoku Chemicals Co., Ltd.)
・ Triethyl borate (reagent)
・ Trimethyl phosphate (reagent)
・ Tributyl phosphate (reagent)
・ Tris phosphate (reagent)
Filler / Calcium carbonate (Whiteon B Shiraishi Calcium Co., Ltd.)

Examples 1-5 and Comparative Examples 1-7 are adjusted. The mixture of the component (A) and the component (B) or the component (B ′) is adjusted according to the “state of the component (B) or component (B ′)” in Table 1. “The state of the component (B) or the component (B ′)” indicates how the component (B) or the component (B ′) is mixed with the component (A). “Dispersion” means that the pulverized component (B) is kneaded into the component (A). At that time, it may be dispersed by a three-roll mill or the like. “Dissolution” indicates a state in which the component (A) is heated or compatible at room temperature. When the temperature reaches room temperature, the mixture of the component (A) and the component (B) or the component (B), the component (C), and the inhibitor are weighed in a stirring vessel and stirred for 30 minutes while degassing. Further, component (D) is weighed in a stirring vessel and stirred for 30 minutes. Detailed preparation amounts follow Table 1, and all numerical values are expressed in parts by mass.

About Examples 1-5 and Comparative Examples 1-7, "viscosity measurement", "curability confirmation", and "DMA measurement (dynamic viscoelasticity measurement)" were performed, and the results are summarized in Table 2.

[Viscosity measurement]
A cone plate type rotational viscometer (E type viscometer) adjusted to 25 ° C. using a circulating high-temperature bath is used. 0.4 cc of the composition is collected and discharged to the center of the sample cup. A sample cup is attached to the main body and measurement is performed to obtain “viscosity (Pa · s)”. Here, when the viscosity cannot be measured by recrystallization, it is described as “recrystallization”, and the curability confirmation and DMA measurement (dynamic viscoelasticity measurement) are set to “not measurable”. In consideration of workability, the viscosity is preferably 10 Pa · s or less.
Measurement conditions Cone rotor: 3 ° × R14
Rotation speed: 50rpm
Measurement time: 3 minutes

[Curability check]
The composition is dropped onto a hot plate set at 120 ° C., and a state in which a bar having a sharp tip is brought into contact with the composition without stringing, that is, the time until curing is measured with a timer. The curing time is defined as “curability (second)”. The curability is preferably shorter than 15 seconds.

[DMA measurement (dynamic viscoelasticity measurement)]
The composition is poured into a jig set so that the thickness of the composition is 0.5 mm and defoamed. Then, it hardens | cures at 120 degreeC x 30 minutes, a hardened | cured material is created, and it cuts out in strip shape of width 10mm, and produces a test piece. Attach to the device and measure the storage elastic modulus, loss elastic modulus, and tan δ. ”And the temperature at the maximum value of tan δ is expressed as“ tan δ (° C.) ”. E ″ is preferably 70 ° C. or higher, and tan δ is preferably 80 ° C. or higher.

From Examples 1 to 5, it can be seen that E ″ and tan δ vary depending on the amount of component (B) added. E ″ satisfies 70 ° C. or higher, and tan δ satisfies 80 ° C. or higher. On the other hand, Comparative Example 1 containing no component (B) has a low E ″ and tan δ, and in Comparative Example 2 in which the component (B) is dissolved in the component (A), the component (B) is recrystallized and tested. In Comparative Examples 3 to 7, the component (B ′) can be dissolved in the component (A), but E ″ and tan δ are low.

In order to adjust the references 1 to 7, the pulverized component (B) is kneaded into the component (A), the mixture of the component (A) and the component (B) is adjusted and returned to room temperature. Thereafter, the mixture of the component (A) and the component (B), the component (C) and the inhibitor are weighed in a stirring vessel and stirred for 30 minutes while degassing. Further, component (D) is weighed in a stirring vessel and stirred for 30 minutes. Detailed preparation amounts are in accordance with Table 3, and all numerical values are expressed in parts by mass. Moreover, the storage stability was confirmed about the reference 1-7, and the result was put together in Table 3.

[Conservation check]
A cone plate type rotational viscometer (E type viscometer) adjusted to 25 ° C. using a circulating high-temperature bath is used. 0.4 cc of the composition is collected and discharged to the center of the sample cup. A sample cup is attached to the main body, and “viscosity (Pa · s)” is measured. This is the initial viscosity. Thereafter, each composition is allowed to stand in an atmosphere of 25 ° C., and the viscosity is measured again after 7 days, 14 days, and 21 days. “OL” indicates that the upper limit of the viscometer has been exceeded, and “−” indicates unmeasured.
Measurement conditions Cone rotor: 3 ° × R14
Rotation speed: 10rpm
Measurement time: 3 minutes

Components (A) to (D) were tested in the same manner as in Example 4 to confirm the storage stability when the filler was added and the type of the inhibitor was changed. The curability, E ′, E ″ and tan δ are considered to be at the same level as in Example 4. However, it was found that Reference Examples 1 and 2 were less likely to thicken than other inhibitors and had good storage stability.

Electric and electronic parts and electrical appliances use various members, and heat resistance may be required depending on the field, but there is also a demand to avoid heating as much as possible. Epoxy resins having fast curability tend to have a low glass transition point, but the present invention keeps the glass transition point high and maintains the conventional fast curability, so that it is necessary to avoid heating. It can be used for bonding and can maintain resistance to reliability testing.

Claims (4)

The epoxy resin composition which contains (A)-(D) component and (B) component exists in the state disperse | distributed to (A) component.
Component (A): Epoxy resin that is liquid at 25 ° C. without component (B) Component: Compound (C) that is solid at 25 ° C. and has a triazine skeleton in the molecule and has 3 or more epoxy groups (C) Component: 25 Polythiol compound (D) component liquid at ℃: Curing agent The epoxy resin composition according to claim 1, wherein the component (B) is the following compound.
(D) The epoxy resin composition in any one of Claim 1 or 2 in which a component contains an amine adduct type hardening | curing agent. The epoxy resin composition according to any one of claims 1 to 3, further comprising tributyl borate and / or 2,4,6-trimethoxyboroxine as component (E).