JPH0873558A - Production of epoxy resin - Google Patents

Abstract

PURPOSE: To obtain an epoxy resin excellent in impact resistance, heat resistance, water resistance and adhesion by reacting an acrylic polymer comprising isopropenylphenol as a component with a phenolic resin and epichlorohydrin. CONSTITUTION: This epoxy resin is obtained by reacting an acrylic polymer comprising isopropenylphenol as a component with a phenolic resin and epichlorohydrin. In this way, the acrylic polymer is uniformly dispersed in the form of fine particles in the epoxy resin. It is desirable that the content of the isopropenylphenol of the acrylic polymer is 1-80wt.%. This resin is mixed with a curing agent and a cure accelerator to form an epoxy resin composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an epoxy resin and a method for producing an epoxy resin composition. More specifically, the present invention relates to a method for producing an epoxy resin, which is excellent in impact resistance, heat resistance, water resistance, adhesiveness, etc. and does not cause mold stains during molding, and a method for producing an epoxy resin composition.

[0002]

2. Description of the Related Art Epoxy resins have a well-balanced performance in terms of thermal, mechanical and electrical characteristics, and therefore have been used in electrical and electronic component materials, adhesives, paints, civil engineering and construction materials, etc. Widely used. However, epoxy resin has the disadvantage that it is essentially brittle,
As a method for improving it, a method of blending a plasticizing component, a method of reducing a crosslinking density by using a monofunctional epoxy compound in combination, and the like have been studied.

However, in these methods, the heat resistance of the epoxy resin is remarkably lowered by the presence of the plasticizing component, so that a fundamental solution has not been reached. On the other hand, JP-A-61-69827 and JP-A-2-117948 disclose compositions in which rubber particles are directly dispersed in an epoxy resin. However, in any of these methods, the rubber particles are heated rolls, by a mechanical means such as a mixer, a method of mixing with an epoxy resin, or rubber particles are dispersed in an organic solvent, after mixing this with an epoxy resin, Since this method is a method of removing the solvent, the rubber particles are unevenly distributed and do not disperse in fine particles. Therefore, the effect of modifying impact resistance and the like is poor relative to the amount added, and the heat resistance also decreases. Further, during molding with these rubber-modified epoxy resin and curing agent, bleeding of the rubber component causes stains on the molding die, which hinders continuous production.

JP-A-59-12920 discloses a thermosetting resin composition obtained by blending an epoxy resin with a phenol novolac resin as a curing agent and a copolymer containing isopropenylphenol as one component. Has been done. However, this composition induces mold fouling during molding.

Japanese Unexamined Patent Publication (Kokai) No. 62-106948 discloses an IC encapsulant composition comprising 100 parts by weight of a novolac type phenol resin and 5 to 100 parts by weight of a polymer having alkenylphenol as one component. It is also disclosed that it can form a cross-linking bond between epoxy resins. However, this composition is disclosed in
As in Japanese Patent No. 12920, it induces mold stains during molding.

In any case, under the limited conditions during molding,
Bleeding occurred due to insufficient cross-linking between the copolymer containing alkenylphenol as a component and the epoxy resin.The haze of the appearance of the molded product due to the bleeding of these polymers, the molding die Contamination occurs and productivity is greatly impaired.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its purpose is to disperse an acrylic polymer finely and uniformly in an epoxy resin. , Shows excellent impact resistance, heat resistance, water resistance, and adhesiveness as a whole epoxy resin, various molding materials, adhesives,
An object of the present invention is to provide a method for producing an epoxy resin suitable for paints, sealants, etc., and a method for producing an epoxy resin composition obtained by this method.

[0008]

DISCLOSURE OF THE INVENTION The present inventors have paid attention to the current state of the art as described above, and have been keen on a composition in which an acrylic polymer particle is dispersed in an epoxy resin as a component for improving brittleness. I have been considering. As a result, an acrylic polymer containing isopropenylphenol as one component,
In the epoxy resin obtained by reacting phenolic resin and epichlorohydrin in the presence of a catalyst, it is possible to disperse the acrylic polymer into fine particles, and to improve impact resistance without impairing other properties. It has been found that it is possible to greatly improve the sex.

The present invention will be described in detail below. The acrylic polymer comprises isopropenylphenol and one or more acrylic polymerizable monomers. Isopropenylphenol includes orthoisopropenylphenol, metaisopropenylphenol, paraisopropenylphenol,
Alternatively, it is a mixture thereof, or a dimer or oligomer thereof. The content of isopropenylphenol in the acrylic polymer is preferably 1 to 80% by weight.

As the acrylic polymerizable monomer, styrene, vinyltoluene, acrylonitrile, methacrylonitrile, acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, Examples thereof include hydroxyethyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hydroxyethyl methacrylate, diethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, glycidyl methacrylate and the like. These monomers can be used alone or in combination.

The acrylic polymer can be polymerized by radical polymerization, ionic polymerization, charge transfer polymerization or the like, and as the reaction form, emulsion polymerization, suspension polymerization, solution polymerization or the like. Radical polymerization using a radical polymerization initiator is excellent in terms of ease of reaction control. As the radical polymerization initiator, azo-based initiators such as azobisisobutyronitrile, azobisisovaleronitrile, and azobiscyclohexanecarbonitrile, benzoyl peroxide, lauroyl peroxide, acetyl peroxide, cumene hydroperoxide, t- There are peroxide initiators such as butyl hydroperoxide, redox initiators such as benzoyl-N, N-dimethylaniline peroxide, peroxodisulfate-sodium bisulfite and the like.

Further, a solvent may be used in producing the acrylic polymer. Examples of the solvent include methyl ethyl ketone, ethyl acetate, dioxane and the like. Usually, the reaction temperature is 30 to 180 ° C., the reaction pressure is atmospheric pressure, and the reaction time is 1 to 10 hours.

Examples of the phenol resin include phenols such as phenol, cresol, xylenol, resorcinol, bisphenol A, paratertiary butylphenol, paraoctylphenol and paranonylphenol, and an aqueous formaldehyde solution, paraformaldehyde,
There is a novolak type resin obtained by reacting with formaldehydes such as trioxane using an acidic catalyst. Examples of commercially available products include Orsocresol Novolac OCN-100 manufactured by Meiwa Kasei Co., Ltd., Novolac # 3000 and VR-9300 manufactured by Mitsui Toatsu Chemicals, Inc. Further, there are phenol aralkyl resins derived from phenols and para-xylylene dihalides such as para-xylene dichloride, and phenols and para-xylylene dialkyl ethers such as para-xylylene dimethyl ether. As an example of a commercially available product, Mirex X manufactured by Mitsui Toatsu Chemicals, Inc.
The L-225 series is an example. Two or more of these phenolic resins may be used in combination.

The amount of the acrylic polymer used is 1 to 100 parts by weight, preferably 2 to 80 parts by weight, based on 100 parts by weight of the phenol resin.

The acrylic polymer and the phenol resin are easy to handle if the acrylic polymer is melt-mixed in a pot after the phenol resin is produced and before discharge.

The epoxy resin is a one-step method for simultaneously carrying out an addition reaction of an acrylic polymer, a phenol resin, and an excess of epichlorohydrin in the presence of an alkali metal hydroxide and a ring-closing reaction to form an epoxy ring, and the presence of a basic catalyst. It can be produced by a two-step method or the like in which an addition reaction is performed below, and then an alkali metal hydroxide is added to carry out a ring-closing reaction.

First, the one-step method will be described. In the one-step method, after mixing the acrylic polymer, the phenol resin, and epichlorohydrin, the reaction temperature is 50 to 150 ° C. and the pressure is 1
The alkali metal hydroxide is continuously or dividedly added in the range of 00 mmHg to atmospheric pressure, and the epoxidation reaction is performed for 1 to 10 hours. After completion of the reaction, excess epichlorohydrin is recovered, then an organic solvent is added to form a solution, the by-produced alkali metal salt is removed by washing or filtration, and the organic solvent is recovered to obtain the epoxy resin of the present invention. Here, the conditions of the acrylic polymer and the phenol resin are in accordance with the above-mentioned conditions.

The amount of epichlorohydrin used is 1 equivalent of the hydroxyl group of the phenolic resin containing the acrylic polymer.
3 to 10 equivalents are preferred.

The amount of the alkali metal hydroxide used is preferably 0.9 to 1.1 equivalents relative to 1 equivalent of the hydroxyl group of the phenol resin. As the alkali metal hydroxide, sodium hydroxide, potassium hydroxide and the like are used, and they can be used as they are in a solid state, but it is convenient in handling to use them as an aqueous solution of 20 to 50% by weight, and preferably 40
Used as an aqueous solution of ~ 50% by weight.

Methyl isobutyl ketone, toluene and xylene are used as organic solvents.

Next, the two-step method will be described. In the two-step method, after the acrylic polymer, the phenol resin, the epichlorohydrin and the basic catalyst are mixed, the reaction temperature is 50 to 15
The addition reaction is carried out at 0 ° C. and atmospheric pressure for 1 to 10 hours. Furthermore, reaction temperature 50 to 150 ° C., pressure 100 mm
The alkali metal hydroxide is continuously or dividedly added in the range of Hg to atmospheric pressure, and the ring-closing reaction is carried out for 1 to 10 hours. After the reaction was completed, excess epichlorohydrin was recovered,
Next, an organic solvent is added to form a solution, and the by-produced alkali metal salt is washed or filtered to remove the organic solvent, whereby the epoxy resin of the present invention is obtained. Here, the conditions of the acrylic polymer and the phenol resin are in accordance with the above-mentioned conditions.

The amount of epichlorohydrin used is based on 1 equivalent of the hydroxyl group of the phenolic resin containing the acrylic polymer.
3 to 10 equivalents are preferred.

The amount of the basic catalyst used is preferably 0.0002 to 0.3 equivalent with respect to 1 equivalent of the hydroxyl group of the phenol resin. As the basic catalyst, tetramethylammonium chloride, tetramethylammonium bromide, tetraethylammonium chloride, tetraethylammonium bromide, tetrabutylammonium chloride,
Quaternary ammonium salts such as tetrabutylammonium bromide, trimethylbenzylammonium chloride, triethylbenzylammonium chloride are used.

The amount of the alkali metal hydroxide used is preferably 0.9 to 1.1 equivalents relative to 1 equivalent of the hydroxyl group of the phenol resin. The type, form, etc. are the same as in the one-step method.

The above-mentioned phenol resin can be used as a curing agent. The mixing ratio of the curing agent is preferably such that the hydroxyl group equivalent of the curing agent is 0.8 to 1.2 with respect to the epoxy equivalent of the epoxy resin.

The curing accelerator is usually a commercially available catalyst and is not particularly limited. Examples of the curing accelerator include triphenylphosphine, tris-2,6 dimethoxyphenylphosphine, tri-p-tolylphosphine, phosphorus compounds such as triphenylphosphite, 2-methylimidazole, 2-phenylimidazole, and 2-ethyl. Examples thereof include imidazoles such as -4-methylimidazole, and tertiary amines such as 2-dimethylaminomethylphenol and benzyldimethylamine. The amount of the curing accelerator compounded is
The amount is preferably 0.1 to 3.0% by weight based on the epoxy resin of the present invention.

In the present invention, in addition to the above-mentioned components, various compounds may be blended as required. For example, a filler, a surface treatment agent for treating the surface of the filler, a flame retardant, a release agent, and a coloring agent. The filler is not particularly limited, and examples thereof include crystalline silica, fused silica, alumina, talc, calcium silicate, clay and the like. Examples of the surface treatment agent include silane coupling agents and titanate coupling agents. Examples of the flame retardant include antimony trioxide, antimony pentoxide, phosphate and bromide. Examples of the release agent include waxes such as carnauba wax, and examples of the colorant include carbon black.

According to the method for producing an epoxy resin of the present invention, the difference in solubility between the acrylic polymer and the epoxy resin due to the progress of epoxidation from the state where the acrylic polymer is uniformly dissolved in the phenol resin. By utilizing, it is possible to uniformly disperse a fine-grained acrylic polymer having a maximum particle size of 0.2 μm or less in the epoxy resin. This effect cannot be obtained simply by mixing the epoxy resin with the acrylic polymer.

In the present invention, by using an acrylic polymer having isopropenylphenol as one component, the hydroxyl group of isopropenylphenol forms a crosslinked structure with the epoxy resin in the epoxidation reaction.

[0030]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples. In addition, the parts described in Examples and Comparative Examples, and%
Means parts by weight and% by weight unless otherwise specified. Production Examples 1 to 5 350 parts of methyl ethyl ketone was charged into a reactor equipped with a stirrer, a reflux condenser and a thermometer, and the temperature was raised with stirring. The temperature of the reactor was maintained at 80 to 90 ° C. from the start to the end of the polymerization in order to continue the reflux of methyl ethyl ketone. When the methyl ethyl ketone started to reflux, the monomer solution (a) having the composition shown in Table 1 and the catalyst solution (b) were simultaneously added dropwise. The dropping is completed in 3 hours and 1 more after the dropping.
After the polymerization for a period of time, the catalyst solution (c) was added dropwise for 15 minutes and further polymerized for 2 hours to obtain an acrylic polymer solution having a solid content concentration of 60% (polymer Nos. 1 to 5).

[0031]

[Table 1] AN: acrylonitrile n-BA: n-butyl acrylate n-BM: n-butyl methacrylate PIPE: p-isopropenylphenol MEK: methyl ethyl ketone ABIN: azobisisovaleronitrile

Production Examples 6 to 12 Acrylic polymer solutions and orthocresol novolac (trade name OCN, manufactured by Meiwa Kasei Co., Ltd.) according to the ratios shown in Table 2.
-100) was charged into a reactor, uniformly mixed with heating and dissolved, and then the solvent was removed under reduced pressure to obtain a mixture of an acrylic polymer and a phenol resin. (Resin No. 1
~ 7)

[0033]

[Table 2] OCN: Orthocresol Novolac

Examples 1 to 4 Mixtures of the acrylic polymers obtained in Production Examples 6 to 9 and phenolic resins (resin Nos. 1 to 1) in accordance with the proportions shown in Table 3.
4) was heated while being dissolved in epichlorohydrin with stirring to raise the temperature to 110 ° C. A 48% aqueous sodium hydroxide solution was continuously added dropwise thereto under atmospheric pressure for reaction for 3 hours. During this time, water generated by the reaction and water of the sodium hydroxide aqueous solution were azeotropically distilled with epichlorohydrin to continuously remove them out of the reaction system. After completion of the reaction, excess epichlorohydrin was removed by evaporation under atmospheric pressure and further evaporated at 150 ° C. under a reduced pressure of 20 mmHg. Methyl isobutyl ketone was added to and dissolved in the produced epoxy resin, water was further added and mixed, and then the mixture was allowed to stand and the lower layer aqueous sodium chloride solution was separated and removed. Methyl isobutyl ketone resin solution is removed by evaporating most of methyl isobutyl ketone under normal pressure and then removing
Evaporation was performed at 150 ° C. under reduced pressure of mHg to obtain an epoxy resin in which the acrylic polymer was finely dispersed. The dispersed particle size and dispersed state of the acrylic polymer in this resin were observed with a transmission electron microscope. The results are shown in Table 4.

[0035]

[Table 3] EP: epichlorohydrin Alkali: 48% NaOH aqueous solution

Example 5 50 parts of the acrylic polymer solution obtained in Production Example 2 and orthocresol novolac (trade name OCN-, manufactured by Meiwa Kasei Co., Ltd.)
100 parts of 100 parts and 648 parts of epichlorohydrin were charged into a reactor and heated while stirring and dissolving, and the temperature was raised to 70 ° C. A 48% aqueous sodium hydroxide solution was continuously added dropwise thereto under atmospheric pressure for reaction for 3 hours.
After the completion of the reaction, the produced water, water of sodium hydroxide aqueous solution, methyl ethyl ketone of the acrylic polymer solution, and excess epichlorohydrin are removed by evaporation under atmospheric pressure,
Further, an epoxy resin was obtained under the same conditions as in Examples 1 to 4 except that evaporation was performed at 150 ° C under a reduced pressure of 20 mmHg. The epoxy equivalent was 249 g / eq. The results are shown in Table 4.

Comparative Examples 1 to 3 Epoxy resins were obtained under the same conditions as in Examples except that the phenol resin compositions obtained in Production Examples 10 to 12 were used according to the ratios shown in Table 3. The results are shown in Table 4.

Comparative Example 4 Epoxy resin (Nippon Kayaku Co., Ltd., trade name EOCN-1)
03S) 100 parts and 33 parts of the acrylic polymer solution (solid content 60%) obtained in Production Example 2 were charged into a reactor and uniformly mixed while heating, and then the solvent was removed under reduced pressure to remove the acrylic system. An epoxy resin containing a polymer was obtained. The epoxy equivalent was 260 g / eq. The results are shown in Table 4.

Comparative Example 5 An epoxy resin was obtained under the same conditions as in Comparative Example 4 except that the acrylic polymer solution obtained in Production Example 4 was used. The epoxy equivalent was 258 g / eq. The results are shown in Table 4.

[0040]

[Table 4] Detection limit 0.01 μm

Test Examples Epoxy resins and curing agents obtained in Examples and Comparative Examples (Mitsui Toatsu Chemical Co., Ltd., trade name XL-225, hydroxyl equivalent 176 g / eq) (however, epoxy equivalent and hydroxyl equivalent) And the equivalent ratio of 1: 1), and 1% by weight of triphenylphosphine with respect to the epoxy resin.
Section, fused silica (BF100 manufactured by Mitsubishi Metals Co., Ltd.) 72
Parts, antimony trioxide 2 parts, carbon black 0.5
And 0.5 parts of carnauba wax were dry-mixed for 60 seconds by a Henschel mixer, and further melt-mixed for 5 minutes by a hot roll at 80 to 90 ° C. After cooling and solidifying, it was pulverized to obtain an epoxy resin composition. Using this composition, a test piece for physical property test was obtained by transfer molding (175 ° C., 30 kg / cm ² , 3 minutes). These test pieces were post-cured at 175 ° C. for 5 hours and then subjected to various tests. The results are shown in Table 5, Table 6 and Table 7.

[0042]

[Table 5] The following notes apply to Table 5, Table 6, and Table 7. * 1: Measurement method JIS K691 * 2: Using a molded product insert-molded by embedding a 30 × 30 × 3 mm copper plate in the bottom surface of a 25 × 25 × 5 mm thick molded product, constant temperature of -40 ℃ and +250 ℃ Put each into the tank for 30 minutes, and inspect the resin part for cracks after repeating 15 cycles. * 3: A disk-shaped molded product having a thickness of 3 mm and a diameter of 50 mm was held in an oven at 85 ° C. and 85% RH for a humidification test for 168 hours, and the water absorption was determined by the following formula. * 4: After repeating molding 30 times with the same mold, visually inspect the stain on the mold surface.

[0043]

[Table 6]

[0044]

[Table 7]

[0045]

As is clear from the examples, the epoxy resin of the present invention has an acrylic polymer content of 0.2 μm or less as compared with a conventional epoxy resin in which an acrylic polymer is dispersed. Since it can be made into fine particles and dispersed uniformly, a cured product using this is excellent in impact resistance, heat resistance, and water resistance. Furthermore, since it has a functional group in a part of the acrylic polymer, since it cross-links with the epoxy resin, there is no bleeding of the acrylic polymer, so there is no mold fouling during molding and it is suitable for continuous production for a long time. It can be said to be an industrially useful invention.

Claims (4)

[Claims] 1. A method for producing an epoxy resin, which comprises reacting an acrylic polymer having isopropenylphenol as one component with a phenol resin and epichlorohydrin. 2. The method according to claim 1, wherein a mixture of an acrylic polymer containing isopropenylphenol as a component and a phenol resin is reacted with epichlorohydrin. 3. The method according to claim 1, wherein the content of isopropenylphenol in the acrylic polymer is 1 to 80% by weight. 4. A method for producing an epoxy resin composition, which comprises the epoxy resin obtained by the method according to claim 1 or 2, a curing agent, and a curing accelerator.