JPH0148290B2 - - Google Patents

Description

[Detailed description of the invention]

A so-called epoxy acrylate resin obtained by adding acrylic acid and/or methacrylic acid [generally referred to as "(meth)acrylic acid" in the following description] to an epoxy resin is known, and this epoxy acrylate resin can be used as desired. It is practically used as a polymerizable curable resin that dissolves in liquid polymerizable monomers to give a cured product that exhibits excellent corrosion resistance, and is used as a material for corrosion-resistant equipment and linings, or to improve mechanical properties. The scope of its application is expanding as automotive parts that take advantage of this. When epoxy acrylate resin is used for the above-mentioned purposes, it is an important requirement that it have a viscosity suitable for workability in the molding process. Possible methods include changing the type and amount of the liquid polymerizable monomer or adjusting the molecular weight of the raw material epoxy resin. In the former method, the physical properties of the target cured product vary significantly, and if a large amount of polymerizable monomer is used, corrosion resistance may be significantly impaired. Therefore, it is generally desirable to adjust the viscosity of the epoxy acrylate resin by adjusting the molecular weight of the raw material epoxy resin. Therefore, the method of adjusting the molecular weight of the raw material epoxy resin is to obtain an epoxy resin having a desired molecular weight, or to mix a low molecular weight epoxy resin and a high molecular weight epoxy resin to prepare an epoxy resin with a desired viscosity. There are three possible methods: or, modifying a low molecular weight epoxy resin with a compound having a phenolic hydroxyl group to prepare a modified epoxy resin having a desired viscosity. but,
Method (2) requires preparing epoxy resins according to the number of types of epoxy acrylate resin, and all epoxy resins used have high viscosity, making handling difficult. It takes a lot of time and heat to mix the epoxy resins together under heating, which ultimately lengthens the total manufacturing time of the epoxy acrylate resin, and therefore, none of these methods are practical. Taking these circumstances into consideration, the above-mentioned method is recommended as a practically desirable means for adjusting the molecular weight of the raw material epoxy resin. By the way, in the reaction of modifying a low molecular weight epoxy resin with a compound having a phenolic hydroxyl group,
It is known to use tertiary amines and quaternary ammonium salts as catalysts, but when these catalysts are used, they can suppress the remaining unreacted phenolic hydroxyl groups in the modified epoxy resin, and It is not necessarily effective in suppressing side reactions such as ring opening of groups and reactions between epoxy groups and alcoholic hydroxyl groups. Incidentally, if the reaction time is short, even if side reactions can be prevented, phenolic hydroxyl groups will remain, and the phenolic hydroxyl groups remaining in the modified epoxy resin may adversely affect the properties of the cured epoxy acrylate resin or cause foaming during curing. In addition, if the reaction time is long, even if the residual phenolic hydroxyl group can be suppressed, the side reactions described above will occur, which will induce an undesirable increase in the molecular weight and increase the viscosity of the epoxy acrylate resin. This is also extremely inconvenient in terms of product quality control. Therefore, when using the above catalysts, a compromise method is adopted to adjust the reaction time to balance the amount of residual phenolic hydroxyl groups and the amount of side reaction products, and the gelation time and viscosity may vary depending on the product number. Fluctuations are unavoidable, which is a major drawback in production management. The present inventors have conducted extensive research to find a method for stably producing a high-quality epoxy acrylate resin by eliminating the drawbacks of such conventional methods, and have completed the present invention. That is, in the present invention, an epoxy resin (a) and a compound (b) having a phenolic hydroxyl group are reacted to obtain a modified epoxy resin, and then the modified epoxy resin and (meth)acrylic acid are reacted with a polymerization inhibitor. In the method of producing a polymerizable curable resin by reacting in the presence of a polyurethane resin, the side reaction to suitably carry out the reaction for producing the modified epoxy resin is suppressed, and unreacted phenolic hydroxyl groups substantially remain. The present invention relates to a catalyst for producing a modified epoxy resin that does not have a modified epoxy resin, and a method for suitably carrying out the reaction. Hereinafter, aspects of the method of the present invention will be specifically explained. In the method of the present invention, a phosphine compound represented by the following general formula is used as a catalyst for the reaction between the epoxy resin (a) and the compound (b) having a phenolic hydroxyl group. (In the formula, R ₁ , R ₂ and R ₃ are a hydrogen atom, a halogen atom, an alkyl group having 1 to 7 carbon atoms, a cycloalkyl group, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted aralkyl group, and may be the same or different.) is used. The amount of phosphine compound used is based on raw material (a)
It is selected in a range of 0.001 to 1.0% by weight based on the sum of component and component (b). Using this catalyst, the above (a) and
By reacting (b) with
The reaction substantially proceeds down to 5 ppm or less. In addition, side reactions such as ring opening of epoxy groups and reactions between epoxy groups and alcoholic hydroxyl groups are suppressed.
This prevents undesirable high molecular weight build-up. In this way, it has become possible to produce a modified epoxy resin that always has a stable molecular weight depending on the blending ratio of the epoxy resin and the compound having a phenolic hydroxyl group. The phosphine compounds used here are:
In relation to the reaction conditions, it is necessary to have a boiling point of 100°C or higher at 760 mmHg. Phosphine; triphenylphosphine,
Specific examples include tertiary phosphine such as tricyclohexylphosphine and phenyldichlorophosphine. Furthermore, the present inventors have found that the catalytic activity of the phosphine compound can be effectively maintained by maintaining the reaction system in an inert gas atmosphere. That is, by keeping the reaction system under an inert gas atmosphere, the decomposition of the phosphine compound is suppressed, which not only contributes to completing the desired reaction with a given amount of catalyst, but also contributes to the completion of the desired reaction with a predetermined amount of catalyst. This provides advantages such as allowing the use of large amounts of catalyst. Incidentally, phosphine compounds may cause coloring of modified epoxy resins or curable resins obtained by reacting them with (meth)acrylic acid, and therefore the amount of phosphine compounds used should be smaller. desirable. Inert gases used here include nitrogen gas, helium,
Examples include argon and carbon dioxide gas, and by continuously introducing these inert gases into the reaction system, the intended purpose can be achieved.
When the desired reaction is carried out by maintaining the reaction system in an inert gas atmosphere, the catalytic phosphine compound is
Based on the sum of component (a) and component (b), preferably
Used in amounts ranging from 0.01 to 0.2% by weight. Incidentally, when the reaction system is not carried out under an inert gas atmosphere, the phosphine compound is desirably selected in a larger amount of 0.05 to 0.5% by weight. In the method of the present invention, when the modification reaction of the epoxy resin with a compound having a phenolic hydroxyl group is carried out in an inert gas atmosphere, after the reaction is completed, the reaction system contains oxygen or an oxygen-containing compound represented by air. By introducing gas, the phosphine compound used as a catalyst in the modification reaction is deactivated. Immediately after the modification reaction of the epoxy resin with a compound having a phenolic hydroxyl group by deactivating the phosphine compound, a phenolic polymerization inhibitor represented by hydroquinone is added to carry out the reaction with (meth)acrylic acid. be able to. By deactivating the phosphine compound, the reaction between the epoxy group of the modified epoxy resin and the phenolic hydroxyl group of the phenolic polymerization inhibitor can be suppressed. In the present invention, the deactivation of the phosphine compound is to eliminate factors that inhibit the reaction between the modified epoxy resin and (meth)acrylic acid, and is not particularly limited to the use of a phenolic polymerization inhibitor. Examples of the epoxy resin used in the method of the present invention include those commonly called epoxy resins having at least 1.8 epoxy groups in one molecule, and among them, bis(4-hydroxyphenyl)methane, 2 Epoxy resins obtained by reacting compounds having polyvalent phenolic hydroxyl groups such as , 2-bis(4-hydroxyphenyl)propane and phenol novolak with epihalohydrin such as epichlorohydrin and methylepichlorohydrin are particularly suitable. used for. Compounds with phenolic hydroxyl groups used to modify epoxy resins include monocyclic polyhydric phenols represented by hydroquinone, resorcinol, catechol, etc.; bis(4-hydroxyphenyl)methane, 1,1- Bisphenols represented by bis(4-hydroxyphenyl)ethane and 2,2-bis(4-hydroxyphenyl)propane; polyhydric phenols such as phenol novolak obtained by the reaction of phenol and formaldehyde Compounds can be mentioned. Furthermore, monovalent phenols such as phenol and para-t-butylphenol may be used by mixing them with the multi-group phenol compound, and the average value is 1.8 or more phenols in one molecule. It is sufficient that a phenolic hydroxyl group is present. A modified epoxy resin obtained by reacting an epoxy resin with a compound having a phenolic hydroxyl group in the presence of a phosphine compound is reacted with (meth)acrylic acid in the presence of a polymerization inhibitor to form a so-called epoxy acrylate resin. It will be destroyed. According to the method of the present invention, it is possible to stably produce an epoxy acrylate resin that has excellent curing properties and has a desired viscosity. The epoxy acrylate resin can be dissolved in a liquid polymerizable monomer as desired, but it is also possible to react the modified epoxy resin with (meth)acrylic acid in the presence of a liquid polymerizable monomer. good. As the above-mentioned polymerizable monomer, any monomer that can be copolymerized with the epoxy acrylate resin can be used. For example, (meth)
Examples include acrylic esters, styrene and substituted derivatives thereof, divinylbenzene, vinyl acetate, diallyl phthalate, and the like. In addition, known polymerization inhibitors include hydroquinones such as hydroquinone and methylhydroquinone; benzoquinones such as rosebenzoquinone and paratoluquinone; catechols such as t-butylcatechol; and metal compounds such as copper naphthenate and triphenylstibine. Polymerization inhibitors can be used. The method of the present invention will be specifically explained below using Examples and Comparative Examples. Example 1 3 m ² equipped with stirrer, reflux condenser and thermometer
In a reaction vessel, 876 kg of bisphenol-based epoxy resin with an epoxy equivalent of 187 (manufactured by Ciba Geigy, trade name "Araldite #260") and bisphenol were added.
Add 187.6 kg of A and 1.06 kg of triphenylphosphine and react at 120°C for 1 hour.
A modified epoxy resin was obtained. Reaction product at 100℃
745 kg of styrene, 261.7 kg of methacrylic acid, 0.54 kg of hydroquinone and 2.6 kg of dimethylbenzylamine were added to this, and the temperature was raised to 120°C and reacted for 3 hours, resulting in an acid value of 10.5 mgKOH/g and a viscosity of
Epoxy acrylate resin (1) of 420 cps (25°C) was obtained. Example 2 In Example 1, triphenylphosphine was
2.12Kg is used, but the same raw materials are used in the same amount.
A modified epoxy resin having an epoxy equivalent of 354 was obtained by reacting at 150°C for 5 hours. Next, an epoxy acrylate resin was produced in the same manner as in Example 1. The obtained epoxy acrylate resin (2) has an acid value of 11.1 mg.
KOH/g, viscosity 427 cps (25°C). Example 3 In the same reactor as in Example 1, 875 kg of novolac-based epoxy resin with an epoxy equivalent of 175 (manufactured by Shell Chemical Co., trade name "Epicote #152"), 57 kg of bisphenol A, and triphenylphosphine were added.
0.9 kg was added and reacted at 130°C for 2 hours to obtain a modified epoxy resin with an epoxy equivalent of 235. The reaction product was cooled to 100℃, and 686 kg of styrene and acrylic acid were added.
288Kg, hydroquinone 0.4Kg and dimethylbenzylamine 2.44Kg were added and reacted at 120°C for 2 hours to obtain an epoxy acrylate resin (3) with an acid value of 16.7mgKOH/g and a viscosity of 190cps (25°C). Comparative Example 1 In Example 2, trimethylbenzylammonium chloride was used instead of triphenylphosphine.
Epoxy equivalent was determined using the same procedure except using 2.66Kg.
385 modified epoxy resin was obtained. reaction product 100
℃, 732Kg of styrene, 237.6Kg of methacrylic acid, 0.52Kg of hydroquinone, and 1.2Kg of dimethylbenzylamine were added, and the temperature was raised to 120℃ and reacted for 2.5 hours, resulting in an acid value of 14.1mgKOH/g and a viscosity of
Epoxy acrylate resin (4) of 590 cps (25°C) was obtained. The performance of each of the epoxy acrylate resins obtained in Examples 1 to 3 and Comparative Example 1 is shown below.
Shown in 1. From the results in Table 1, it can be seen that the modified epoxy resin obtained using the phosphine compound as a catalyst provides excellent performance to the epoxy acrylate resin.

【table】

[Table] Example 4 Epoxy equivalent weight 187 was placed in two four-necked flasks equipped with a stirrer, reflux condenser, thermometer and gas inlet tube.
687g of bisphenol-based epoxy resin (manufactured by Ciba Geigy, trade name "Araldide #260"),
147 g of bisphenol A and 0.42 g of triphenylphosphine were added and reacted at 130° C. for 1 hour while flowing nitrogen at a rate of 500 ml/min to obtain a modified epoxy resin with an epoxy equivalent of 350 and a Gardner color number of 2. Thereafter, air was flowed at a rate of 200 ml/min for 1 hour at the same temperature. The reaction product has a Gardner color number of 1
The color was decolored to below, and the catalytic activity of triphenylphosphine disappeared. Next, without cooling the reaction products, 0.42 g of hydroquinone, 612 g of styrene, 205 g of methacrylic acid and dimethylbenzylamine were added.
Add 2.1g and react at 120℃ for 3 hours, acid value 12.5
An epoxy acrylate resin (5) having mgKOH/g, viscosity 438 cps (25°C) and Gardner color number 4 was obtained. Example 5 Into the same reaction apparatus as in Example 4, 788 g of Novotic epoxy resin with an epoxy equivalent weight of 175 (manufactured by Shell Chemical Co., Ltd., trade name "Epicote #152"), 51 g of bisphenol A, and 0.17 g of tricyclohexylphosphine were added. A reaction was carried out at 150° C. for 0.5 hour while nitrogen was flowing at a rate of 500 ml/min to obtain a modified epoxy resin having an epoxy equivalent of 237 and a Gardner color number of 1 to 2. Thereafter, air was flowed at the same temperature for 0.5 hours at a rate of 500 ml/min to eliminate the catalytic activity of tricyclohexylphosphine. The Gardner color number of the resin at this time was 1. Next, without cooling the reaction products, hydroquinone 0.36g, styrene 617
g, 259 g of acrylic acid and 2.2 g of dimethylbenzylamine were added and reacted at 130°C for 1.5 hours to produce an epoxy acrylate resin (6) with an acid value of 14.7 mg KOH/g, a viscosity of 202 cps (at 25°C), and a Gardner color number of 3 to 4. I got it. Example 6 In the same reaction apparatus as in Example 4, 687 g of a bisphenol epoxy resin with an epoxy equivalent of 187 (manufactured by Ciba Guide Ghee, trade name "Araldite #260"),
Add 147 g of bisphenol A and 1.67 g of triphenylphosphine and react at 130°C for 1 hour.
After that, the temperature was raised to 150℃, and then 500ml of air was added at the same temperature.
The catalytic activity of triphenylphosphine was eliminated by flowing the mixture for 1.0 hour at an amount of min. The Gardner color number of the modified epoxy resin at that time was 1 to 2. Next, without cooling the reaction product, 0.42 g of hydroquinone, 612 g of styrene, 205 g of methacrylic acid and 2.1 g of dimethylbenzylamine were added, and the mixture was heated to 120°C.
Reacted for 2.5 hours, acid value 13.4mgKOH/g, viscosity
An epoxy acrylate resin (7) of 415 cps (25° C.) and Gardner color number 5 was obtained. Reference example 1 2 equipped with a stirrer, reflux condenser and thermometer
In a three-necked flask, 687 g of bisphenol-based epoxy resin with an epoxy equivalent of 187 (manufactured by Ciba Geigy, trade name "Araldite #260"), 147 g of bisphenol A, and 1.67 g of triphenylphosphine.
was added and reacted at 130°C for 1 hour, and the epoxy equivalent
351, a modified epoxy resin having a Gardner color number of 3 was obtained. Next, without cooling the reaction products, 0.42 g of hydroquinone, 612 g of styrene, and 205 g of methacrylic acid were added.
g and dimethylbenzylamine 2.1 g,
Reacted at 120℃ for 2.5 hours, acid value 13.1mgKOH/g,
An epoxy acrylate resin (8) with a viscosity of 421 cps (25° C.) and a Gardner color number of 7 was obtained. The performance of each of the epoxy acrylate resins obtained in Examples 4 to 6 and Reference Example 1 is shown below.
Shown in 2. From the results in Table 2, it can be seen that by applying the operating method of the present invention, an epoxy acrylate resin with excellent color tone and good stability can be obtained.

[Table] ** Same as above

Claims (1)

[Claims] 1. A modified epoxy resin is obtained by reacting an epoxy resin (a) with a compound (b) having a phenolic hydroxyl group, and then the modified epoxy resin and (meth)acrylic acid are reacted in the presence of a polymerization inhibitor. In the method for producing a polymerizable curable resin by reacting with a phosphine compound represented by the following general formula, the reaction for producing the modified epoxy resin is (In the formula, R ₁ , R ₂ and R ₃ are a hydrogen atom, a halogen atom, an alkyl group having 1 to 7 carbon atoms, a cycloalkyl group, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted aralkyl group, and may be the same or different). 2. The method according to claim 1, wherein the phosphine compound is used in an amount ranging from 0.001 to 1% by weight based on the sum of components (a) and (b). 3 The epoxy resin (a) and the compound (b) having a phenolic hydroxyl group are reacted to obtain a modified epoxy resin, and then the modified epoxy resin and (meth)acrylic acid are reacted in the presence of a polymerization inhibitor to polymerize. In the method for producing a curable resin, the reaction for producing the modified epoxy resin is carried out using a phosphine compound represented by the following general formula. (In the formula, R ₁ , R ₂ and R ₃ are a hydrogen atom, a halogen atom, an alkyl group having 1 to 7 carbon atoms, a cycloalkyl group, a substituted or unsubstituted phenyl group, or a substituted or unsubstituted aralkyl group, and may be the same or different) in an inert gas atmosphere, and after the reaction is completed, an oxygen-containing gas is blown into the reaction system. Production method.