JPS6320850B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a novel vinyl ester resin which is dissolved in a vinyl monomer and whose cured product has high heat resistance and flexibility, and a method for producing the same. [Prior art and problems to be solved by the invention] In recent years, unsaturated epoxy ester resins (vinyl ester resins), which are made by dissolving a reaction product of an epoxy resin and an unsaturated monobasic acid in a polymerizable monomer such as styrene, have been developed. However, it is steadily being used in the market as it combines the performance of epoxy resin with the workability and curing properties of unsaturated polyester resin. Similar to unsaturated polyester resins, vinyl ester resins are used in a wide range of applications, including corrosion-resistant reinforced plastic materials, lining materials, coating materials, impregnation materials, adhesives, and casting materials. Moreover, this vinyl ester resin can be made to have a wide variety of performances by selecting epoxy compounds having different types and degrees of polymerization as the ester component, or by blending these. The vinyl ester resin is produced by ring-opening the epoxy group of an epoxy compound with the carboxyl group of an unsaturated monobasic acid such as acrylic acid, methacrylic acid, etc.
It is produced by a reaction that involves esterification to produce an epoxy ester. As the epoxy resin used for the most general vinyl ester resin, a diglycidyl ether type of bisphenol A is used. However, these vinyl ester resins made from diglycidyl ether type epoxy of bisphenol A have poor acid resistance and alkali resistance.
Although it has dramatically higher performance than general unsaturated polyester resin, its heat distortion temperature is only
Use at high temperatures of around 110°C is severely restricted. In addition, conventionally commercially available epoxy acrylate resins having a novolac skeleton are produced by reacting epichlorohydrin with novolac obtained by reacting a phenol compound and formalin to obtain the following formula []
Novolac type epoxy resin shown by [In the formula, R is H or _CH3 , and n represents an integer of 0 to 10. ] and reacts this with acrylic acid and/or methacrylic acid in the presence of a vinyl monomer solvent such as styrene or methyl methacrylate to produce a vinyl monomer solution of the resin. This epoxy acrylate resin (vinyl ester resin) having a novolak skeleton is represented by the following formula []. [In the formula, R is H or CH ₃ , and ExAc is

[Means for solving problems]

The present invention has been made to solve these problems, and the present invention has the following general formula [] [In the formula, R is a methyl group or a hydrogen atom, n is 0-
Indicates 15 integers. ] The present invention provides a novel vinyl ester resin shown in the following and a method for producing the same. The novel vinyl ester resin of the present invention represented by the above general formula [] is characterized in that it is dissolved in a vinyl monomer and the cured product thereof has high heat resistance and flexibility. In addition, the new vinyl ester resin of the present invention represented by the general formula [] is the following general formula [] [In the formula, R is a methyl group or a hydrogen atom, n is 0-
Indicates 15 integers. ] It is obtained by reacting the dicyclopentadiene-modified epoxy resin represented by acrylic acid or a reactive derivative of acrylic acid. In the present invention, the dicyclopentadiene-modified epoxy resin represented by the above general formula [] is obtained by polymerizing dicyclopentadiene and phenols (phenol, orthocresol, valaclesol, isopropylphenol, etc.) in a Lewis acid catalyst. It can be obtained by reacting dicyclopentadiene-modified phenolic resin with epichlorohydrin. In the esterification reaction between the dicyclopentadiene-modified epoxy resin represented by the above general formula [] and acrylic acid, acrylic acid is added per equivalent of epoxy group.
Mix at a ratio of 0.5 to 1.8 equivalents, preferably 0.7 to 1.1 equivalents, in the presence of an esterification catalyst at a temperature of 70 to 180°C, preferably 90 to 130°C, so that the resulting resin has an acid value of 1 to 16. It can be suitably produced by reacting until the Such ester reaction is preferably carried out in an oxygen or air atmosphere. Generally the reaction time is 2 to 16 hours, preferably 4 to 16 hours.
It is 8 hours. As the reaction solvent, any solvent that does not inhibit the esterification reaction can be used as necessary. In order to obtain a cured product without distilling off the solvent, it is convenient to use a vinyl monomer such as styrene or divinylbenzene that is copolymerizable with the vinyl ester resin to be produced. It is not preferable to use an excessive amount of acrylic acid because it reduces the rate of esterification reaction with the epoxy resin and significantly deteriorates the alkali resistance of the cured product obtained. Further, a part of the acrylic acid may be replaced with a saturated monobasic acid, a saturated dibasic acid, or an unsaturated dibasic acid. These acids are based on the total acid component used.
It is advisable to use amounts up to 80% by weight, preferably from 10 to 60% by weight. Examples of acids that can be used in place of some of the above acrylic acids include propionic acid, benzoic acid, phthalic acid, terephthalic acid, tetrahydrophthalic anhydride, succinic acid, adivic acid, fumaric acid,
Examples include maleic anhydride. As the esterification catalyst used in the present invention,
For example, (1) N,N-dimethylaniline, pyridine, triethylamine, hexamethylenediamine, etc.
amines and their salts with inorganic acids such as hydrochloric acid or with organic acids such as acetic acid. (2) 4 such as tetramethylammonium bromide, trimethylbenzylammonium chloride, etc.
grade ammonium salt. (3) Sulfonic acids and sulfonium salts such as para-toluenesulfonic acid and triphenylsulfonium chloride. (4) Sulfonium salts such as trimethylsulfonium chloride and dimethylphenylsulfonium chloride. (5) Phosphonium salts such as phosphonium iodide. (6) Metal halides such as lithium chloride, lithium bromide, stannous chloride, and zinc chloride. (7) Metal hydroxides such as potassium hydroxide and lithium hydroxide. Among these esterification catalysts, tetraethylammonium bromide has much better compatibility with dicyclopentadiene-modified epoxy resin than other catalysts, provides a fast reaction rate, and is capable of achieving a high reaction rate. This is preferable because it can be done. These esterification catalysts are used in a proportion of 0.005 to 3 parts by weight based on 100 parts by weight of the mixture of epoxy resin and acid component. Furthermore, the ester reaction is preferably carried out in the presence of a polymerization inhibitor, and such polymerization inhibitors include:
For example, p-hydroquinone, naphthoquinone, benzoquinone, ditertiarybutyl hydroxytoluene, hydroquinone monomethyl ether,
Examples include mono- or polyhydric phenols such as tertiary-butylcatechol, and quinones. The amount used is about 0.001 to 1.0 parts by weight, preferably 0.005 to 0.5 parts by weight, based on 100 parts by weight of the reaction mixture. Although the vinyl ester resin produced by the practice of the present invention can be cured alone in the presence of a polymerization initiator, the vinyl ester resin can be dissolved in a vinyl monomer copolymerizable with it to form a low viscosity resin. It is easier to handle if it is in liquid form. At this time, the vinyl monomer is a vinyl ester resin.
30 to 120 parts by weight, preferably 40 parts by weight per 100 parts by weight
It is used in a proportion of ~80 parts by weight. Examples of such vinyl monomers include styrene,
Examples include methyl acrylate, methyl methacrylate, vinyltoluene, chlorostyrene, vinylbenzene, acrylonitrile, methacrylonitrile, cyclopentadiene, cyvinylbenzene, vinylpyridine, vinyl acetate, diacrylphthalate, glycidyl methacrylate, etc. The above can also be used together. After the reaction is completed, polyacrylate is precipitated by adding a poor solvent for polyacrylate, such as water, and separated from the solvent. Additionally, by adding a poor solvent for organic acids and a good solvent for polyacrylate, such as methyl isobutyl ketone, toluene, xylene, chloroform, methyl ethyl ketone, etc., the polyacrylate is transferred from the organic acid layer to these solvent layers, and the organic acid After separating the layers, these solvents are distilled off to separate the polyacrylate. The polyacrylate thus obtained is dissolved together with a polymerization initiator in an organic solvent such as acetone, toluene, chloroform, or methyl acetate, or in a vinyl monomer such as methyl methacrylate or styrene.
Used in paints and prepregs. The liquid vinyl ester resin diluted with the vinyl monomer is then cured at room temperature in the presence of a polymerization initiator such as a combination of methyl ethyl ketone peroxide and cobalt salt, similar to the liquid unsaturated polyester resin composition. It is also possible to cure at a high temperature by adding a high temperature decomposition polymerization initiator such as benzoyl peroxide. [Example] The present invention will be further explained with reference to Examples below.
In the examples, parts and percentages are by weight unless otherwise specified. Example 1 500 parts of dicyclopentadiene-modified epoxy resin (DCE-400, epoxy equivalent 280 g/eq),
150 parts of acrylic acid, 3.0 parts of tetramethylammonium bromide, 0.3 parts of hydroquinone, and 1500 parts of toluene were placed in a flask equipped with a stirring blade and a condenser, and the reaction was carried out by heating to 100°C on an oil solution. After 3 hours, the acid The price was almost unbearable. Add 10% sodium hydrogen carbonate aqueous solution to this reaction solution.
Excess acrylic acid was removed by adding 200 ml and 1000 ml of distilled water, and after extraction and washing three times with 1000 ml of distilled water, the organic layer was separated and the organic solvent was distilled off to obtain 593 g of the desired new vinyl ester resin. . The analysis results are shown in Table 1. To 100 parts of this reaction product, 54 parts of styrene was added and mixed to obtain a viscous solution with a Gardner hue of 7 to 8 and a viscosity of 3.5 voids at 25°C. Example 2 A target resin was obtained under the same conditions as in Example 1 except that 2.5 parts of triethylbenzylammonium bromide was used as the esterification catalyst. The analysis results are shown in Table 1.

【table】 [Brief explanation of the drawing]

Figure 1 is a chart showing the infrared absorption spectrum of the vinyl ester resin of Example 1 of the present invention, Figure 2 is a chart showing the GPC (ultrafiltration chromatograph) of the same resin, and Figure 3 is a chart showing the infrared absorption spectrum of the vinyl ester resin of Example 1 of the present invention. FIG. 4 is a chart showing the GPC of the vinyl ester resin of Example 2, and FIG. 4 is a chart showing the nuclear magnetic resonance spectrum of the present invention.

Claims (1)

[Claims] 1. The following general formula [] [In the formula, R is a methyl group or a hydrogen atom, n is 0 to 15
indicates an integer. ] A new vinyl ester resin. 2 General formula [] [In the formula, R is a methyl group or a hydrogen atom, n is 0 to 15
indicates an integer. ] A method for producing a novel vinyl ester resin represented by the following general formula [ ], which comprises reacting a dicyclopentadiene-modified epoxy resin represented by the formula with acrylic acid or a reactive derivative of acrylic acid. [In the formula, R is a methyl group or a hydrogen atom, n is 0 to 15
indicates an integer. ]