JPH03243610A - Stabilization of vinyl ester resin - Google Patents

Abstract

PURPOSE:To obtain a resin composition having excellent high-temperature stability and improved stability in reaction and storage and useful for coating material, adhesive, corrosion-resistant FRP, high-strength FRP, UV curable material, etc., by adding a specific amount of a specific nitroso compound to a vinyl ester resin. CONSTITUTION:The objective composition can be produced by adding 0.01-5.0 pts.wt. of a nitroso compound of formula (R is 1-6C alkyl, phenyl or its alkyl derivative) (e.g. N-methyl-N-nitrosoaniline or N-phenyl-N-nitrosoaniline) to 100 pts.wt. of a vinyl ester resin (e.g. produced by reacting an epoxy resin with an unsaturated monobasic acid at 90-150 deg.C).

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is applicable to paints, adhesives, corrosion-resistant FRP, high-strength FRP,
This article relates to the composition of vinyl ester resins useful for various uses such as ultraviolet curing and electron beam curing.

(Prior Art) Currently, as a method for stabilizing vinyl ester resins, a method of adding a polymerization inhibitor such as hydroquinones or quinones is used.

On the other hand, vinyl ester resins are cured by radical polymerization by adding curing catalysts, curing accelerators, etc. during use, so if a large amount of polymerization inhibitor is added to stabilize the resin, it will take a long time to cure during use. There may be cases where it is necessary or the case is not cured. Therefore, restrictions are naturally placed on the amount of polymerization inhibitor added. Such practical vinyl ester resins have extremely poor high temperature stability and gelation occurs when they are dissolved in polymerizable monomers during or after the reaction. In order to prevent gelation, a method of blowing a gas containing oxygen, such as air, into the system has been adopted, but this may require an air blowing device in the reaction equipment, or the high temperature stability of the resin may be insufficient. There are drawbacks.

(Problem to be solved by the invention) As mentioned above, when trying to improve the stability of vinyl ester resin by adding hydroquinones or quinones, the amount of polymerization inhibitor added increases, resulting in extreme curability during use. The disadvantage is that it is slow.

An object of the present invention is to improve the stability during reaction and storage without adversely affecting the curability of vinyl ester resins during use.

(Means for Solving the Problems) As a result of intensive research on methods for stabilizing vinyl ester resins, the present inventor found that when a nitroso compound represented by general formula (I) is added during or after vinyl ester synthesis, vinyl ester resins It has been discovered that this method improves the high-temperature stability of the compound and does not adversely affect the curability during use.

Representative examples of the nitroso compound represented by the general formula (I) used in the present invention include N-methyl-N-nitrosoaniline and N-phenyl-N-nitrosoaniline, but the effects of the present invention are The compound is not limited to. In addition, the amount added is 0.01 to 5.0 parts by weight per 100 parts by weight of the vinyl ester resin; if it is less than 0.01 parts by weight, the stabilizing effect will decrease, and if it is more than 5.0 parts by weight, the stabilizing effect will not be effective. Although it improves, the curing properties may be delayed and complete curing may not be achieved.

The epoxy compound, unsaturated basic acid, esterified IvlJIc, polymerization inhibitor, and polymerizable monomer used in the vinyl ester resin of the present invention are not particularly limited, and all known ones can be used.

Epoxy compounds include bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, phenol novolak glycidyl ether, gresol novolanoglycidyl ether, polyethylene glycol diglycidyl ether, phthalic acid diglycidyl ester, adipic acid diglycidyl ester, Hexahydrophthalic acid diglycidyl ester, epoxidized polybutadiene, and the like are used alone or in combination.

In addition, the above-mentioned epoxy resin can be used with polyhydric alcohols such as bisphenol A, ethylene glycol, diethylene glycol, and polyethylene glycol, and organic polybasic acids such as phthalic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, and terminally carboxylated polybutadiene, or their like. Pre-denatured anhydrides can also be used.

As the unsaturated basic acid, acrylic acid, methacrylic acid, etc. can be used. Examples of the esterification S medium include quaternary ammonium salts such as trimethylbenzylammonium chloride, tertiary amines such as dimethylbenzylamine, and phosphines such as triphenylphosphine. As a polymerization inhibitor, P-butylcatechol,
2,5-di-t-butylhydroquinone, monobutylhydroquinone, hydroquinone, toluhydroquinone, p-benzoquinone, naphthoquinone, methoxyhydroquinone, phenothiazine, etc. can be used alone or in combination. The amount added is preferably 0.01 to 0.1% in consideration of curability. As the polymerizable monomer, styrene monomer, methyl methacrylate, trimethylolpropane tri(meth)acrylate, 2-
Examples include hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and triethylene glycol di(meth)acrylate, which can be used alone or in combination.

The vinyl ester resin in the present invention can be obtained using a known reaction method. For example, an epoxy resin and an unsaturated basic acid are reacted at 90 to 150°C. If necessary, the reaction can be carried out by adding a known polymerization inhibitor or polymerizable monomer or by blowing air into the mixture. The effect of the nitroso compound of general formula (I) remains the same even if it is added at the start of the reaction, during the reaction, or at any time after the end of the reaction.

When the amount of polymerization inhibitor is reduced in order to make the vinyl ester resin harden quickly, gelation often occurs during the reaction, but gelation can be prevented by using the nitroso compound of general formula (I) in combination. I can do it. Furthermore, when a vinyl ester resin is reacted under an inert gas, it gels during the reaction, but gelation can be prevented by adding a nitroso compound of general formula (I) to the reaction.

(Examples) Examples will be described below to specifically explain the present invention, but it goes without saying that the present invention is not limited to the examples.

Example 1 374 g of bisphenol A epoxy resin (AER-331 manufactured by Asahi Kasei Corporation) with an epoxy equivalent of 187, 172 g of methacrylic RA, 1.6 g of triethylamine, and hydroquinone were placed in a flask equipped with a stirrer, a cooling tube, a gas introduction tube, and a thermometer. ○ Qg, add 58g of styrene monomer 1
While flowing air through the reaction system at a rate of 60 m (1/min),
React for 2 hours at 0 to 130°C with acid value 15KOH/
It was cooled at g. After that, the styrene monomer 17 was heated at 40°C.
6 g and 1.6 g of N-methyl-N-nitrosoaniline were added to obtain a vinyl ester resin (A).

Table 1 shows the 120°C storage stability and curing properties of this resin.

Example 2 A flask equipped with a stirrer, a cooling tube, a gas inlet tube, and a thermometer was charged with 1187 epoxy bisphenol A epoxy resin (M Kasei Co., Ltd.'M A E R-331) 374
g, methacrylic lol! 172g, triethylamine 1
．． 6g, hydroquinone 0.2g, styrene monomer 5
8g was added to the reaction system, and while air was flowing at a rate of 601Q/min, the reaction was carried out at 110-130℃ for 2 hours until the acid value was 15.
It was cooled with KOH/g.

Thereafter, 176 g of styrene monomer and 4.0 g of N-phenyl-N-nitrosoaniline were added at 40°C to obtain a vinyl ester resin (B).

Table 1 shows the 120°C storage stability and curing properties of this resin.

Example 3 374 g of bisphenol A type epoxy resin (manufactured by M Kasei Co., Ltd., AER~331) with an epoxy equivalent of 187, 172 g of methacrylic acid, and 1.6 g of triethylamine were placed in a flask equipped with a stirrer, a cooling tube, a gas introduction tube, and a thermometer. , 0.2 g of hydroquinone, 1.6 g of N-methyl-N-nitrosoaniline, and 58 g of styrene monomer were added, and while blowing air at 60 mQ 1 minute into the reaction system, 110 to 13
The mixture was reacted at 0° C. for 2 hours and cooled to an acid value of 14 KOH/g. Thereafter, 176 g of styrene monomer was added at 40°C to obtain vinyl ester resin (C).

Table 1 shows the 120°C storage stability and curing properties of this resin.

Example 4 A phenol novolak type epoxy resin (DOW Chemical Company DEN-438) 364 having an epoxy equivalent of 182 was placed in a flask equipped with a stirrer, a cooling tube, a gas inlet tube and a thermometer.
g, methacrylic acid 172g, triethylamine 1.6
g, 0.3 g of methylhydroquinone, and 76 g of styrene monomer were added, and while air was flowing through the reaction system at 60 mQ for 1 minute, the reaction was carried out at 110 to 130°C for 2 hours until the acid value was 12.
It was cooled with KOH/g. Thereafter, 154 g of styrene monomer and 1 N-methyl-N-nitrosoaniline were heated at 40°C.
．． 6 g was added to obtain vinyl ester resin (D). Table 1 shows the 120°C storage stability and curing properties of this resin.

Example 5 374 g of bisphenol A type epoxy resin (manufactured by M Kasei Co., Ltd., AER-331) with an epoxy equivalent of 187, 144 g of acrylic acid, and 1.6 g of triethylamine were placed in a flask equipped with a stirrer, a cooling tube, a gas introduction tube, and a thermometer. , hydroquinone 0.2 g, N-methyl-N-nitrosoaniline 1
．． 6g, trimethylolpropane triacrylate 58
g and allowed to react at 110 to 130°C for 2 hours while blowing air through the reaction system at a rate of 60 mQ/min until the acid value was 14 K.
It was cooled with OH■/g. Thereafter, 176 g of trimethylolpropane triacrylate was added at 40°C to obtain vinyl ester resin (E). Table 1 shows the storage stability of this resin at 120°C.

Example 6 In a flask equipped with a stirrer, a cooling tube, a gas inlet tube, and a thermometer, 374 g of bisphenol A epoxy resin (AER-331 manufactured by Asahi Kasei Corporation) with an epoxy equivalent of 187, 172 g of methacrylic acid, 1.6 g of triethylamine, Add 0.2 g of hydroquinone, 1.6 g of N-methyl-N-nitrosoaniline, and 58 g of styrene monomer, and while flowing N2 gas into the reaction system at a rate of 60 mQ/min,
The mixture was reacted at 30° C. for 2 hours and cooled to an acid value of 13 KOH/g. Thereafter, a vinyl ester resin (F) to which 176 g of styrene monomer was added was obtained at 40°C.

Table 1 shows the 120°C storage stability and curing properties of this resin.

Comparative Example 1 In a flask equipped with a stirrer, a cooling tube, a gas inlet tube, and a thermometer, 374 g of bisphenol A type epoxy resin AER-331 (manufactured by CM Kasei C Co., Ltd.) having an epoxy equivalent of 187, 172 g of methacrylic acid, 1.6 g of triethylamine, Add 0.2 g of hydroquinone and 58 g of styrene monomer, and while blowing air into the reaction system at a rate of 6011 Q/min,
React at 10-130℃ for 2 hours to obtain acid value 15KOH/
It was cooled at g. After that, the styrene monomer 17 was heated at 40°C.
6 g was added to obtain vinyl ester resin (G).

Add 0.05 parts of hydroquinone to 100 parts of vinyl ester resin (G) to make vinyl ester resin (H).
I got it.

Table 1 shows the storage stability and curing properties of vinyl ester resins (G) and (H) at 120°C.

Comparative Example 2 A phenol novolac type epoxy resin (DEN-438 manufactured by Dow Chemical Company) 364 with an epoxy equivalent of 182 was placed in a flask equipped with a stirrer, a cooling tube, a gas inlet tube, and a thermometer.
g, methacrylic acid 172g, triethylamine 1.6g
, 0.3 g of methylhydroquinone and 76 g of styrene monomer were added, and while air was flowing through the reaction system at a rate of 60 mQ/min, the reaction was carried out at 110 to 130°C for 2 hours until the acid value was 12.
It was cooled with KOH/g. Thereafter, 154 g of styrene monomer was added at 40°C to obtain vinyl ester resin (I).

0.05 part of methylhydroquinone was added to 100 parts of vinyl ester resin (I).
J) was obtained.

Table 1 shows the 120°C storage stability and effectiveness of vinyl ester resins (I) and (J).

Comparative Example 3 In a flask equipped with a stirrer, a cooling tube, a gas inlet tube, and a thermometer, 374 g of epoxy F187 bisphenol A epoxy resin (AER-331 manufactured by M Kasei Co., Ltd.), 144 g of acrylic acid, and 1.6 g of triethylamine were added. , 0.2 g of hydroquinone and 58 g of trimethylolpropane triacrylate were added, and air was introduced into the reaction system at 60 raQ1.
The reaction mixture was allowed to react for 2 hours at 110 to 130 DEG C. and cooled to an acid value of 14 KOH/g. Thereafter, 176 g of trimethylolpropane triacrylate was added at 40°C to obtain a vinyl ester resin (K).

Table 1 shows the storage stability of this resin at 120°C.

Comparative Example 4 374 g of bisphenol A type epoxy resin (AER-331 manufactured by Asahi Kasei Corporation) with an epoxy equivalent of 187 was placed in a flask equipped with a stirrer, a cooling tube, a gas introduction tube, and a thermometer.
172 g of methacrylic acid, 1.6 g of triethylamine,
Add 0.2 g of hydroquinone and 58 g of styrene monomer, and react at 110 to 130°C while flowing N2 scum into the reaction system at a rate of 60 Q/min. After 30 minutes, the acid value is 8.
Gelled at 5 KOHag/g.

1 25℃ pot gel Measurement conditions 55% methyl ethyl ketone peroxide / 6% cobalt naphthenate = 1.510.5 Phr 120℃ Storage stability measurement method JIS 18■ test tube with resin A to the height of IOam
t. Leave it in an oil bath at 120°C and measure the time until the resin gels.

(Effects of the Invention) Although vinyl ester resins exhibit excellent properties such as corrosion resistance, mechanical properties, heat resistance, and photocurability, they are poor in stability and may gel during the reaction.

The method of the present invention has little effect on the curability of the resin and greatly improves its stability during reaction and storage, making it possible to safely produce the resin.

Claims (1)

[Claims] For 100 parts by weight of vinyl ester resin, the following general formula (
A resin composition having excellent high-temperature stability, characterized in that 0.01 to 5.0 parts by weight of a nitroso compound represented by I) is added. General formula (I) ▲ Numerical formulas, chemical formulas, tables, etc. are available▼ Here, R represents an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an alkyl derivative thereof.