JPH04139256A - Epoxy resin composition and cured material - Google Patents

Abstract

PURPOSE:To obtain an epoxy resin composition suitable for various materials in a civil engineering and building fields, etc., having excellent fluidity and resistance to alkali by mixing the epoxy resin with a filler comprising mixed powder of a curing agent, silica and alumina spherical granules. CONSTITUTION:An epoxy resin is mixed with a filler composed of a mixed powder of a curing agent (e.g. carboxylic acid-based anhydride or amine-based compound), silica and alumina spherical granules obtained by explosion of aluminum powder. As the alumina spherical granules, globular granules having 0.3-5 micron averaged granular diameter and 8-20m<2>/g specific surface area are preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION The industrial invention provides an epoxy resin composition that provides a cured product with good fluidity and excellent alkali properties, and is useful as various materials in the civil engineering and architectural fields, electrical and electronic fields, etc. It relates to a product and its cured product.

Epoxy resin compositions that stretch easily are used in large quantities as insulating materials for electrical and electronic applications, but recently they are also often used in the civil engineering and construction fields. Characteristics different from those required for use in the field have come to be required.

That is, in the civil engineering and construction fields, epoxy resin compositions are used as adhesives for ALC and concrete, or as casting materials in concrete frames, but in this case, since concrete itself is alkaline, the epoxy resin composition is There is a problem in that the cured epoxy resin product deteriorates due to alkali when the cured resin product is in contact with the resin for a long time. Therefore, it has been desired to improve the alkali resistance of cured epoxy resin products.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide an epoxy resin composition that provides a cured product with good fluidity and excellent alkali resistance, and a cured product thereof.

In order to achieve the above object, the inventor of the present invention has made intensive studies and found that silica and aluminum powder are deflagrated as fillers for an epoxy resin composition containing an epoxy resin, a hardening agent, and a filler. The VMC method (Vaporized
A mixed powder with alumina spherical particles obtained by the metal combing method) is used, and preferably the alumina spherical particles are blended so that the specific surface area of the alumina spherical particles accounts for 50% or more of the specific surface area of the entire filler. 2. The alkali resistance of the cured product is dramatically improved without impairing the fluidity of the epoxy resin composition. Therefore, in addition to good fluidity, it has excellent alkali resistance, as well as crank resistance and thermal conductivity. Provides a cured product with excellent properties,
We have discovered that epoxy resin compositions useful as various materials such as adhesives, casting materials, insulating materials, and sealing materials can be obtained in the civil engineering and architectural fields, electrical and electronic fields, etc., and have come to form the present invention. Ta.

Therefore, the present invention provides an epoxy resin composition containing an epoxy resin, a curing agent, and a filler, in which a mixed powder of silica and alumina spherical particles obtained by deflagrating aluminum powder is blended as a filler. The present invention provides an epoxy resin composition and a cured product obtained by curing this composition.

The present invention will be explained in more detail below.

The epoxy resin composition of the present invention is composed of an epoxy resin, a curing agent, a filler, and, if necessary, a curing accelerator, a mold release agent, a silane coupling agent, and the like.

Here, as the epoxy resin used in the present invention, any type of general-purpose epoxy resin can be used,
For example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, cresol novolak type epoxy resin, phenol novolac type epoxy resin, glycidyl ether type epoxy resin, glycidyl ester type epoxy resin, glycidylamine type epoxy resin, aliphatic epoxy resin, Examples include cyclic epoxy resins, heterocyclic epoxy resins, halogenated epoxy resins, hydantoin type epoxy resins, and the like. The above epoxy resins may be used alone or in combination of two or more.

Further, as the curing agent, carboxylic acid anhydrides, amine compounds, compounds having a phenolic hydroxyl group, and the like are preferably used. In this case, examples of the carboxylic anhydride include phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, nadic anhydride, methylnadic anhydride, succinic anhydride, trimellitic anhydride, and pyromellitic anhydride. , 3.3', 4.4'-benzophenonetetracarboxylic anhydride, chlorendic acid anhydride, etc.
In addition, examples of amine compounds include meta-phenylene diamine, para-phenylene diamine, 2,6-diamitupyridine, 1,4-naphthylene diamine, 2,6-naphthylene diamine, 4,4'-diaminodiphenylmethane, , 4'-diaminodiphenyl ether and the like. Furthermore, examples of the compound having a phenolic hydroxyl group include phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, and the like. These curing agents may be used alone or in combination of two or more.

The amount of the curing agent to be blended is not particularly limited, but the amount of curing agent such as phenol resin or acid anhydride is 30 to 120 parts, especially 40 to 120 parts, per 100 parts (by weight, same hereinafter) of the epoxy resin.
100 parts, and 30 to 70 parts, especially 30 to 50 parts of an amine curing agent such as an aromatic amine.

Furthermore, it is preferable to add a curing accelerator to the composition of the present invention in order to promote the reaction between the epoxy resin and the curing agent. As the curing accelerator, compounds commonly used for curing epoxy resins, such as 3R amines, imidazoles, organic phosphines, and cycloamidines, are used. Note that the amount of the curing accelerator used is not particularly limited, and may be a normal amount.

The epoxy resin composition of the present invention contains an epoxy resin and a curing agent as essential components, and is obtained by adding a curing accelerator as necessary. Blend the mixed powder with the alumina spherical particles obtained in .

Various types of silica can be used, but
For example, fused silica obtained by melting crushed stone and naturally occurring crystalline silica powder are preferably used, and the silica powder may be dry-pulverized using a ball mill or vibration mill, or wet-pulverized. However, either one can be used.

Furthermore, any shape of silica, such as crushed type or spherical type, may be used, and these may be used as a blend.

Note that the average particle size of silica is preferably 0.1 to 10 microns, particularly 0.3 to 5 microns in order to prevent sedimentation.

Next, the alumina spherical particles used together with the silica in the present invention are produced by deflagration of aluminum powder (VMC method:
Vaporized Metal Combustio
n method).

Such alumina spherical particles are disclosed in, for example, Japanese Patent Application Laid-Open No. 60-255.
It can be produced by the VMC method described in Japanese Patent No. 602. That is, first, a reaction vessel is filled with a reaction gas containing oxygen, and aluminum powder is dispersed in this reaction gas to form a highly concentrated dust cloud. Next, when this aluminum dust cloud is ignited, thermal energy is imparted to the aluminum surface, the surface temperature of the aluminum powder increases, and aluminum vapor spreads from the aluminum surface to the surrounding area.

This aluminum vapor mixes with the reactant gas to create an ignited flame. The resulting aluminum vapor and reaction gas are then mixed, causing a chain reaction of ignition, but at this time the aluminum powder itself also ruptures and scatters, promoting the spread of the flame. After combustion, the alumina gas is naturally cooled,
Alumina particles grow, usually with an average particle size of 0.01~2o
Micron spherical particles can be obtained.

Since the alumina spherical particles obtained by the VMC method are particles grown during the natural cooling process, they are said to have higher surface activity than conventional spherical particles that are melted and spheroidized at high temperatures. By mixing these alumina spherical particles with a silica filler and adding them to an epoxy resin composition, the alkali resistance of the cured epoxy resin product can be significantly improved.

In the present invention, among the alumina spherical particles obtained by the above VMC method, true spherical alumina particles having an average particle size of 0.1 to 10 microns, particularly 0.3 to 5 microns are preferably used. If the average particle size is less than 0.1 micron, the flow characteristics of the epoxy resin composition may deteriorate, and if it exceeds 10 microns, the filler will easily settle when the composition is used for casting. There are cases.

Also, the specific surface area of alumina spherical particles is 5 to 30rr? /
g, especially preferably 8 to 20 m/g,
If the specific surface area is less than 5 m/g, a large amount of alumina particles must be added to improve the alkali resistance of the composition, and the particle size of particles with this kind of specific surface area is generally smaller than the average particle size. may become larger than 5 microns and cause sedimentation, and -force specific surface area is 30r.
If it exceeds rr/g, the particle size of the alumina particles becomes too fine, which may increase the viscosity of the composition and reduce workability such as casting.

Furthermore, as the alumina spherical particles, alumina particles 5
The acidity (pH) of the extracted water when extracting g in 50 mQ of pure water at 121°C and 2.1stm for 20 hours.
is preferably 3 to 5, especially 4 to 5, and acidity (p
If H) is less than 3, the acidity is too strong and the epoxy resin and alumina particles may thicken or gel when mixed. If it exceeds 5, even if alumina particles are mixed with the epoxy resin, It may not be sufficiently effective in improving alkali resistance.

Furthermore, the amount of the alumina spherical particles blended is such that the specific surface area of the alumina spherical particles is 50% or more, particularly 60 to 80% of the specific surface area of the total filler filled in the epoxy resin composition. Therefore, it is desirable to increase the filling rate of the alumina spherical particles so that the above-mentioned amount is achieved, or to use alumina spherical particles with a large specific surface area. The content of alumina spherical particles has a specific surface area of 5
If the amount is less than 0%, the alkali resistance may not be improved and the object of the present invention may not be achieved.

It is preferable that the above-mentioned silica or alumina spherical particles blended as a filler are surface-treated in advance with a coupling agent such as silane, aluminum, or titanium before use. In this case, the amount of the coupling agent blended is preferably 0.2 to 3 parts per 100 parts of the filler, and if it is less than 0.2 parts, the effect of improving wettability with the resin may not be obtained. However, if the amount exceeds 3 parts, the effect proportional to the amount added may not be obtained.

In addition, in the present invention, other fillers such as aluminum hydroxide, calcium silicate, calcium carbonate, magnesia, crystalline silica, clay, kaolin, talc, mica, silicon carbide, Silicon tinide, boron tinide, zinc white, titanium oxide, carbon black, antimony dioxide, etc. may also be blended.

In the present invention, the amount of filler blended is not particularly limited, but 5 parts per 100 parts of the total amount of epoxy resin and curing agent.
It is desirable to use 0 to 600 parts, especially 100 to 400 parts; if it is less than 50 parts, the expansion coefficient may increase, and if it exceeds 600 parts, the viscosity of the composition may increase and workability may decrease. be.

Various additives may be further added to the composition of the present invention if necessary, such as a mold release agent, a flame retardant, a coloring agent, etc., as appropriate to the extent that they do not impede the effects of the present invention. I can do it.

In addition, when producing the epoxy resin composition of the present invention, predetermined amounts of the above-mentioned components are uniformly stirred and mixed, and
It can be obtained by heating to 0 to 95°C, kneading with a kneader, roll, extruder, etc., cooling, and pulverizing. It is preferable to thoroughly knead the filler and epoxy resin under reduced pressure before adding the curing agent, then add the curing agent, curing accelerator, etc., and further knead thoroughly. By this method, it is possible to obtain a composition in which sedimentation hardly occurs.

As mentioned above, the epoxy resin composition of the present invention is suitable for civil engineering and
It can be effectively used in the construction field as an adhesive for ALC and concrete, and as a casting material in concrete frames. In this case, the molding temperature of the epoxy resin composition is 100-180°C, and the post-curing temperature is 150-180°C.
It is preferable to carry out the reaction at 80'C for 2 to 4 hours.

Highlights The epoxy resin composition of the present invention has good fluidity and provides a cured product having excellent alkali resistance.
Therefore, it can be widely used in the civil engineering and construction fields as an adhesive for ALC and concrete, as a casting material in concrete frames, and as a rim material and sealing material in the electrical and electronic fields.

EXAMPLES Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In addition, in the following examples, all parts are parts by weight.

[Examples 1 to 3, Comparative Examples 1 and 2] Epikote 828 (epoxidized bisphenol A, manufactured by Yuka Shell Epoxy Co., Ltd.) was used as the epoxy resin, and MH700 (methylhexahydrophthalic anhydride, manufactured by Shin Nihon Rika Co., Ltd.) was used as the curing agent. ), silica A shown in Table 1 as a filler,
Silica B, alumina A, alumina B, and alumina C are the second
Using the compounding composition shown in the table, the filler and epoxy resin were first thoroughly kneaded at 140'C under reduced pressure, then cooled, and a curing agent was added and kneaded to form an epoxy resin composition (Example 1). ~3, Comparative Examples 1 and 2) were obtained.

Next 2 The epoxy resin composition of 2 was cast and heated to 100°C.
A cured product was prepared by heating and curing at 150°C for 6 hours and then at 150°C for 10 hours. At this time, the casting workability and the alkali resistance of the cast product (cured product) were evaluated by the following methods.

The results are also listed in Table 2.

Table 0 γ-Glycidoxyprobyltrimethoxysilane**N
-β(aminoethyl)γ-aminopropyltrimethoxysilane*** 5g of sample was heated at 121°C with 5011112 water, 2.
Extraction was carried out at 1 atm for 20 hours.

Method for evaluating casting workability (1) Fluidity Each of the compositions shown in the Examples was heated at an angle of 45° at room temperature.
A fixed amount of the composition was dropped onto a glass plate tilted at an angle of 100 degrees, and the fluidity was measured by the distance the composition flowed down.

(2) Sedimentability Each of the compositions shown in the examples had a diameter of 3 an.

After pouring into a plastic container with a height of 10 a+t and leaving it for 5 hours at room temperature, the filler content in the upper and lower parts of the container was measured.

The superiority or inferiority of casting workability was determined based on the comprehensive evaluation of (1) and (2).

Evaluation of Alkali Resistance After immersing the cured product in a 0 or 5 normal alkaline aqueous solution at room temperature and leaving it for one week, the surface condition of the cured product was observed and evaluated according to the following criteria.

◎: No change at all O: Slight change △: Change The blended epoxy resin compositions (Examples 1 to 3) had good workability,
Moreover, it was confirmed that a cured product with excellent alkali resistance could be obtained.

Claims (1)

[Claims] 1. In an epoxy resin composition containing an epoxy resin, a curing agent, and a filler, a mixed powder of silica as a filler and alumina spherical particles obtained by deflagrating aluminum powder An epoxy resin composition characterized by containing the following. 2. A cured product obtained by curing the epoxy resin composition according to claim 1.