JPH10176034A - Epoxy resin, epoxy resin composition and cured product of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an epoxy resin composition having a high refractive index and capable of giving an excellent cured product by incorporating an epoxy resin having a specific molecular structure. SOLUTION: This composition comprises an epoxy resin shown by the formula ((n) is an average positive number of 0-10; and G is glycidyl). It also contains, in addition to the above epoxy resin, a curing agent (e.g. diaminodiphenylmethane, diethylenetriamine, phthalic anhydride or imidazole), and further, curing accelerator (e.g. 2-methylimidazole), preferably at 0.7 to 1.2 equivalents per equivalent of the epoxy group in the epoxy resin and 0.1 to 5.0 pts.wt. per 100 pts.wt. of the epoxy resin, respectively. Thus, the cured product obtained from this composition is extremely useful for diversified purposes, e.g. plastic lenses for glasses and Fresnel lenses.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an epoxy resin having a high refractive index and excellent water resistance, an epoxy resin composition, and a cured product thereof.

[0002]

2. Description of the Related Art Organic optical materials are widely used as various materials in recent years because they are lightweight and easy to handle as compared with glass and the like. As such resins for organic optical materials, polystyrene resins, polymethyl methacrylate resins, polycarbonate resins, diethylene glycol diallyl carbonate resins, and the like have been widely used.

[0003] However, such conventional resins for organic optical materials have drawbacks such as low refractive index, large birefringence, and high water absorption, and are inferior in heat resistance and impact resistance. Was. In particular, diethylene glycol allyl carbonate resin used as a material for lenses has a low refractive index of 1.50, so when used for lenses, the edge thickness and center thickness are large,
There are drawbacks in that the appearance of the lens deteriorates and the weight increases.

[0004] In order to solve these drawbacks, various methods for mainly improving the refractive index have been studied. For example, JP-A-5-4404 discloses a resin in which a halogen is introduced into an aromatic ring. However, although the resin obtained by this technique has a high refractive index of 1.60, it has a high specific gravity of 1.37 and is not satisfactory in terms of the lightness of the lens, which is a characteristic of plastic lenses.

[0005]

The above-mentioned resins have any problems in terms of refractive index, specific gravity, water resistance and the like, and the appearance of a resin which can solve these problems at the same time is awaited. ing.

[0006]

In view of these circumstances, the present inventors have found that an epoxy resin having a molecular structure represented by the above formula (1) has a high refractive index and is excellent in a cured product of the composition. It has been found that the present invention exhibits excellent water resistance, and the present invention has been completed.

That is, the present invention provides:

[0008]

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(2) (a) an epoxy resin according to the above (1), wherein n is an average value and represents a positive number from 0 to 10, and G represents a glycidyl group. Resin (b) an epoxy resin composition containing a curing agent, (3) an epoxy resin composition according to the above (2), which contains a curing accelerator, and (4) an epoxy resin according to the above (2) or (3). The present invention relates to a cured product obtained by curing a resin composition.

The epoxy resin represented by the formula (1) is, for example, a compound represented by the formula (2)

[0011]

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The reaction of the compound represented by the formula with epihalohydrin can be carried out in the presence of an alkali metal hydroxide.

As a method for obtaining the epoxy compound of the present invention from the compound represented by the formula (2), a known method can be adopted. For example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is added to a dissolved mixture of the compound represented by the formula (2) and an excess epihalohydrin such as epichlorohydrin or epibromhydrin, or
The epoxy resin of the present invention can be obtained by reacting at 0 to 120 ° C. for 0.5 to 10 hours.

In the reaction for obtaining the epoxy resin of the present invention, an aqueous solution of the alkali metal hydroxide may be used. In this case, the aqueous solution of the alkali metal hydroxide is continuously added to the reaction system. A method may be employed in which water and epihalohydrin are continuously flowed out under reduced pressure or normal pressure, liquids are separated, water is removed, and epihalohydrin is continuously returned into the reaction system.

A quaternary ammonium salt such as tetramethylammonium chloride, tetramethylammonium bromide or trimethylammonium chloride is added to a dissolved mixture of the compound represented by the formula (2) and epihalohydrin as a catalyst. A solid or aqueous solution of an alkali metal hydroxide is added to the halohydrin etherified product of the compound of the formula (2) obtained by reacting for 0.5 to 5 hours, and the reaction is performed again at 20 to 120 ° C. for 0.5 to 10 hours. A method of dehalogenating (ring closing) may be used.

The amount of epihalohydrin used in these reactions is usually 1 to 20 mol, preferably 2 to 10 mol, per 1 equivalent of the hydroxyl group of the compound represented by the formula (2). The amount of the alkali metal hydroxide used is 0.8 to 1.5 with respect to 1 equivalent of the hydroxyl group in the compound represented by the formula (2).
Mole, preferably 0.9 to 1.1 mole. In order to make the reaction proceed smoothly, it is preferable to add an aprotic polar solvent such as dimethyl sulfone and dimethyl sulfoxide in addition to alcohols such as methanol, ethanol and isopropanol to carry out the reaction.

When alcohols are used, they are used in an amount of usually 2 to 50% by weight, preferably 4 to 40% by weight, based on the amount of epihalohydrin. When an aprotic polar solvent is used, it is usually 5 parts by weight based on the amount of epihalohydrin.
It is about 150% by weight, preferably 10 to 140% by weight.

After the reaction product of the epoxidation reaction is washed with water or without water washing, under reduced pressure at 100 to 150 ° C.
At a pressure of 10 mmHg or less, epihalohydrin and aprotic polar solvent are removed. In order to further reduce the amount of hydrolyzable halogenated epoxy compound, the recovered epoxy resin is dissolved again in a solvent such as toluene, methyl isobutyl ketone, methyl ethyl ketone, and an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide. An aqueous solution can be added for further reaction to ensure ring closure. In this case, the amount of the alkali metal hydroxide used is usually 0.01 to 0.3 mol, preferably 0.05 to 1 equivalent of the hydroxyl group of the compound of the formula (2) used for the epoxidation.
０．２0.2 mol. The reaction temperature is 50 to 120 ° C, and the reaction time is usually 0.5 to 2 hours.

After completion of the reaction, the formed salt is removed by filtration, washing with water, and the like, and the solvent such as toluene, methyl isobutyl ketone and methyl ethyl ketone is distilled off under reduced pressure under heating to obtain the epoxy resin of the present invention.

Hereinafter, the epoxy resin composition of the present invention will be described. In the epoxy resin composition according to the above (2) or (3), the epoxy resin of the present invention can be used in combination with another epoxy resin. When used in combination, the proportion of the epoxy resin of the present invention in the total epoxy resin is 3
It is preferably at least 0% by weight, particularly preferably at least 40% by weight.

Other epoxy resins which can be used in combination with the epoxy resin of the present invention include novolak type epoxy resins, bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, and the like. Or two or more of them may be used in combination.

As the curing agent used in the epoxy resin composition of the present invention, for example, an amine compound, an acid anhydride compound, an amide compound, a phenol compound and the like can be used. Specific examples of the curing agent that can be used include diaminodiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, dicyandiamide, a polyamide resin synthesized from a dimer of linolenic acid and ethylenediamine, phthalic anhydride, and trianhydride. Melitic acid, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride,
Methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, methylhexahydrophthalic anhydride, phenol novolak, and modified products thereof, imidazole, BF ₃ -amine complex, guanidine derivative and the like. It is not limited to these. These may be used alone or in combination of two or more.

The amount of the curing agent used in the epoxy resin composition of the present invention is preferably from 0.7 to 1.2 equivalents to 1 equivalent of the epoxy group of the epoxy resin. If the amount is less than 0.7 equivalents or more than 1.2 equivalents with respect to 1 equivalent of epoxy group, curing may be incomplete and good cured physical properties may not be obtained.

When the above curing agent is used, a curing accelerator may be used in combination. Specific examples of the curing accelerator that can be used include imidazoles such as 2-methylimidazole, 2-ethylimidazole, 2-ethyl-4-methylimidazole, 2- (dimethylaminomethyl) phenol, and 1,8-diaza. Tertiary amines such as -bicyclo (5,4,0) undecene-7; phosphines such as triphenylphosphine; and metal compounds such as tin octylate. The curing accelerator is used in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the epoxy resin as required.

The epoxy resin composition of the present invention may optionally contain additives such as an antioxidant, a coloring inhibitor, a release agent, an antifoaming agent, a bluing agent and a fluorescent dye.

The epoxy resin composition of the present invention can be obtained by uniformly mixing the components. The epoxy resin composition of the present invention can be easily made into a cured product by a method similar to a conventionally known method. For example, the epoxy resin of the present invention and a curing agent, and if necessary, a curing accelerator and other compounding materials are sufficiently mixed by using an extruder, a kneader, a roll, or the like, if necessary, to obtain an epoxy resin. A resin composition is obtained, and the epoxy resin composition is melted and then molded using a casting or transfer molding machine.
The cured product of the present invention can be obtained by heating at 00 ° C. for 2 to 10 hours.

The cured product thus obtained has a high refractive index,
Since it has excellent water resistance, it can be used in a wide range of fields requiring high refractive index and water resistance. Specifically, plastic lenses for glasses, Fresnel lenses, lenticular lenses, optical disc substrates, plastic optical fibers,
It is extremely useful as an optical material such as a prism sheet for an LCD or a light guide plate, a paint, an adhesive, and a sealing material, particularly as an optical material. The epoxy resin of the present invention can be acrylated and used as a photocurable material.

[0028]

EXAMPLES The present invention will be described below in more detail with reference to Examples and Comparative Examples. In the following, parts are by weight unless otherwise specified.

Example 1 145 parts of the compound represented by the formula (2) were dissolved in 555 parts of epichlorohydrin while purging the flask equipped with a thermometer, a dropping funnel, a cooling tube and a stirrer with nitrogen gas. The mixture was further heated to 70 ° C., 5 parts of tetramethylammonium chloride was added, and a chlorhydrination reaction was carried out with stirring for 1 hour. Thereafter, 40 parts of sodium hydroxide in the form of flakes were added in portions at 70 ° C. over 100 minutes, and then the mixture was further reacted at 70 ° C. for 2 hours. After the completion of the reaction, 150 parts of water was added, and after washing with water, excess epichlorohydrin was distilled off at 130 ° C. under reduced pressure by heating using a rotary evaporator, and 402 parts of methyl isobutyl ketone was added to the residue and dissolved.

Further, this solution of methyl isobutyl ketone was heated to 70 ° C., and a 30% by weight aqueous sodium hydroxide solution 1 was added.
After adding 0 parts and reacting for 1 hour, washing with water was repeated until the pH of the washing solution became neutral. Further, the water layer is separated and removed,
Using a rotary evaporator, methyl isobutyl ketone was distilled off from the oil layer under heating and reduced pressure to obtain 195 parts of the epoxy resin of the present invention represented by the above formula (1). The obtained epoxy resin is semi-solid and has an epoxy equivalent of 208 g / e.
q.

Example 2, Comparative Example 1 The epoxy resin (A) obtained in Example 1 as Example 2, and the liquid bisphenol A type epoxy resin (Epicoat 828, manufactured by Yuka Shell Epoxy Co., Ltd.) as Comparative Example 1 186 g / eq of epoxy equivalent), using hexahydrophthalic anhydride (Ricacid HH, manufactured by Shin Nihon Rika Co., Ltd.) as a curing agent and triphenylphosphine (TPP) as a curing accelerator. The resin composition was obtained by mixing at the ratios shown in the column. Next, the mixture was heated and mixed, and then cast to prepare a resin molded article, which was cured at 160 ° C. for 2 hours and further at 180 ° C. for 8 hours. Further, the above resin composition was dissolved in acetone, applied on a glass plate, similarly heated and cured to form a thin film having a thickness of 200 μm, and the refractive index was measured.

The results of measuring the physical properties of the cured product thus obtained are shown in Table 1 in the column of physical properties of the cured product. The numerical values in the column of the composition of the composition in Table 1 represent parts by weight. Refractive index 25 ° C using Abbe refractometer (4T type, manufactured by Atago)
Was measured. Water absorption Measured according to JIS K 6911.

[0033]

Table 1 Example 1 Comparative Example 21 1 Composition of the compound Epoxy resin (A) 100 Epicoat 828 100 Ricacid HH 7483 TPP 11 Physical properties of cured epoxy resin Refractive index 1.602 1.547 Water absorption (%) 0.28 0.34

Table 1 shows that the cured product of the epoxy resin of the present invention has a high refractive index and excellent water resistance.

[0035]

EFFECTS OF THE INVENTION The epoxy resin of the present invention can provide a cured product having a high refractive index and excellent water resistance as compared with epoxy resins which have been generally used in the past. Optical materials such as Fresnel lens, lenticular lens, optical disk substrate, prism sheet for LCD, light guide plate, molding material, casting material, laminated material,
It is extremely useful for a wide range of applications, such as paints, adhesives, and resists.

Claims (4)

[Claims] (1) Formula (1) (In the formula, n is an average value, represents a positive number of 0 to 10, and G represents a glycidyl group.) 2. An epoxy resin composition comprising (a) the epoxy resin according to claim 1 and (b) a curing agent. 3. The epoxy resin composition according to claim 2, further comprising a curing accelerator. 4. A cured product obtained by curing the epoxy resin composition according to claim 2 or 3.