JPH08188628A - Resin composition for gel coat and production of gel-coated molding - Google Patents

Abstract

PURPOSE: To obtain a resin composition for a gel coat, excellent in film-forming properties and weather resistance. CONSTITUTION: This resin composition comprises a polymerizable monomer and an unsaturated polyester obtained by effecting the addition reaction of an unsaturated epoxy compound with the terminals of an unsaturated polyester oligomer obtained by reacting an acid component comprising an unsaturated dibasic acid and/or its anhydride and a cycloalkylenedicarboxylic acid and/or its anhydride with a polyhydric alcohol. A gel-coated molding is obtained by forming a gel coat of this composition and forming a fiber-reinforced plastic layer or a resin layer on the gel coat.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition for gel coat, and more particularly to a resin composition for gel coat excellent in film forming property and weather resistance and a method for producing a molded article having a gel coat layer using the same.

[0002]

2. Description of the Related Art FRP (fiber reinforced plastic) molded articles are usually formed by coating a resin composition for gel coating with a thickness of about 0.1 to 0.5 mm on the surface of a molding die and curing it to form a gel coating layer. Then, a composition composed of the unsaturated polyester resin for lamination and glass fiber is laminated on this layer, and after curing, it is obtained by demolding. Further, artificial marble is obtained by casting a composition comprising an unsaturated polyester resin and various fillers on the surface of the gel coat layer, and curing and demolding the composition. The gel coat layer is used for the purpose of decorating, protecting, and improving the aesthetic appearance of various molded products.

However, unsaturated polyester resins generally used as gel coat resins have a problem in weather resistance,
A decrease in gloss such as discoloration or chalking occurs in a short time. Further, a gel coat resin having better weather resistance has a drawback that swelling by the resin composition for lamination, that is, lifting is more likely to occur. Therefore, for molded articles that require weather resistance, a transparent coating such as urethane acrylate is applied to the surface of the gel coat resin layer to prevent discoloration and protection, and the surface is periodically polished to remove the deteriorated layer. The measures are taken. Further, as a lifting prevention measure, it can be improved by increasing the thickness of the gel coat resin layer, but on the other hand, the thicker the gel coat resin layer is, the more the color tends to change.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a resin composition for gel coat excellent in film-forming property and weather resistance, which solves the above-mentioned problems of the prior art, and a molded article having a gel coat layer using the composition. It provides a manufacturing method.

[0005]

In the present invention, an unsaturated dibasic acid and / or its acid anhydride and an acid component consisting of a cycloalkylene dicarboxylic acid and / or its acid anhydride are reacted with a polyhydric alcohol. To the terminal group of the unsaturated polyester oligomer obtained as described above, a gel coat resin composition containing an unsaturated polyester and a polymerizable monomer obtained by adding an unsaturated epoxy compound, and the gel coat resin composition The present invention relates to a method for producing a molded article having a gel coat layer and a gel coat layer on which a fiber reinforced plastic layer or a resin layer is formed.

The unsaturated polyester used in the present invention comprises an unsaturated dibasic acid and / or its acid anhydride and an acid component containing cycloalkylenedicarboxylic acid and / or its acid anhydride, and a polyhydric alcohol. It is obtained by adding an unsaturated epoxy compound to the terminal group of the unsaturated polyester oligomer obtained by the reaction by the method.
As the unsaturated dibasic acid and / or its acid anhydride,
Maleic acid, maleic anhydride, fumaric acid, itaconic acid, citraconic acid and the like are used. These may be used in combination of two or more. As the cycloalkylene dicarboxylic acid and / or its acid anhydride, hexahydrophthalic anhydride, hexahydrophthalic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid and the like are used. These may be used in combination of two or more. The compounding ratio of unsaturated dibasic acid and / or its acid anhydride and cycloalkylenedicarboxylic acid and / or its acid anhydride is usually 30 to 70 mol% for the former and 70 to 30 mol% for the latter.

As the polyhydric alcohol, ethylene glycol, diethylene glycol, propylene glycol,
Dipropylene glycol, 1,3-butanediol,
1,4-butanediol, 2,3-butanediol,
Dihydric alcohols such as 1,5-pentanediol, 1,6-hexanediol, triethylene glycol and neopentyl glycol, trihydric alcohols such as glycerin and trimethylolpropane, and tetrahydric alcohols such as pentaerythritol are used. These may be used in combination of two or more. The reaction between the acid component and the polyhydric alcohol is carried out by a known method, mainly by advancing a condensation reaction, and a low molecule such as water generated when the both components react with each other is released to the outside of the system to proceed. The reaction ratio between the acid component and the polyhydric alcohol is not particularly limited, and is reacted with the unsaturated epoxy compound at the stage of having a carboxyl group at the terminal. The unsaturated polyester oligomer thus obtained has a carboxyl group at the terminal, and an unsaturated epoxy compound such as glycidyl methacrylate is added to this to give an unsaturated polyester.

The method for adding the unsaturated epoxy compound to the terminal carboxyl group of the unsaturated polyester oligomer is not particularly limited, but at 60 to 130 ° C. using a quaternary ammonium salt, metal soap, various amines, etc. as a catalyst. 1
It can be carried out by reacting for 4 hours. The addition reaction includes a method of dissolving an unsaturated polyester oligomer in a polymerizable monomer and then adding an unsaturated epoxy compound, and a method of directly adding an unsaturated epoxy compound to the unsaturated polyester oligomer. A method may be adopted. The amount of the unsaturated epoxy compound compounded is preferably 1.5 to 2.0 times the equivalent of the terminal carboxyl groups of the unsaturated polyester oligomer to be added.

Examples of the polymerizable monomer include styrene, p-methylstyrene, α-methylstyrene, vinyltoluene, divinylbenzene, chlorostyrene, dichlorostyrene, etc., each having one or more polymerizable double bonds in the molecule. Styrene derivative, monomethyl fumarate, dimethyl fumarate, monomethyl maleate, dimethyl maleate, monoethyl fumarate, diethyl fumarate, monoethyl maleate, diethyl maleate, monopropyl fumarate, dipropyl fumarate, monopropyl maleate,
Dipropyl maleate, monobutyl fumarate, dibutyl fumarate, monooctyl fumarate, dioctyl fumarate, monomethyl itaconate, dimethyl itaconate, diethyl itaconate, monoethyl itaconate, monobutyl itaconate, dibutyl itaconate, monopropyl itaconate, Α, β-Unsaturated polybasic acid alkyl ester such as dipropyl itaconate, acrylic acid, allyl acrylate, benzyl acrylate, butyl acrylate, ethyl acrylate, methyl acrylate, propyl acrylate,
Hydroxyethyl acrylate, methacrylic acid, methyl methacrylate, ethyl methacrylate, butyl methacrylate, propyl methacrylate, allyl methacrylate, benzyl methacrylate, hydroxyethyl methacrylate, dodecyl methacrylate, octyl methacrylate, pentyl methacrylate, trimethacrylate. Methylolpropane tri (meth) acrylate (indicates methacrylate or acrylate; hereinafter the same), ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate,
Propylene glycol di (meth) acrylate, 1,6
-Hexanediol di (meth) acrylate, 1,4-
Butanediol di (meth) acrylate, dicyclopentadiene (meth) acrylate, ethylene glycol mono (meth) acrylate, diethyl glycol mono (meth) acrylate, neopentyl glycol di (meth)
Acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolmethane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta ( Acrylic acid such as (meth) acrylate and dipentaerythritol hexa (meth) acrylate, methacrylic acid or a derivative thereof is used. These may be used in combination of two or more.
The amount of the polymerizable monomer is not particularly limited, but the amount of the polymerizable monomer 55 to the unsaturated polyester is 45 to 70% by weight.
A proportion of up to 30% by weight is preferred.

The gel coat resin composition of the present invention contains, if necessary, hydroquinone, pyrocatechol, 2,6
Polymerization inhibitors such as -t-butylparacresol, metal soaps such as cobalt naphthenate and cobalt octenoate,
Quaternary ammonium salts such as dimethylbenzylammonium chloride, β-diketones such as acetylacetone, curing accelerators such as amines such as dimethylaniline, N-ethyl-metatoluidine and triethanolamine, dyes, pigments, plasticizers, and UV absorption. Various additives such as agents, known thixotropic agents such as silica powder and asbestos powder, fillers, stabilizers, defoaming agents and leveling agents can be added. Moreover, you may mix | blend various organic peroxides with a resin composition as a hardening | curing agent. As the organic peroxide, there are methyl ethyl ketone peroxide, benzoyl peroxide, acetylacetone peroxide, bis-4-t-butylcyclohexanedicarbonate, t-butylperoxy-2-ethylhexanate, and the like, and two or more of them are used. You may use together.

A molded article having a gel coat layer according to the present invention is obtained by applying the gel coat resin composition of the present invention to one surface of a molding die by a known method, curing the same, and then laminating it together with glass fiber if necessary. Unsaturated polyester resin (for example, Polyset 5595AP manufactured by Hitachi Chemical Co., Ltd.)
It is obtained by stacking T) on the gel coat layer by a known method, curing it, and then removing from the mold. The unsaturated polyester resin for lamination used is not limited, and orthophthalic acid-based, isophthalic acid-based, vinyl ester-based resins or the like are used.
Examples of the glass fiber include chopped strand mat, spray roving, roving cloth, continuous strand mat, surfacing mat, preformable mat and chopped fiber direct preform. These may be used in combination of two or more. To cure the unsaturated polyester resin for lamination, the organic peroxide used in the resin composition for gel coat described above is used. These may be used in combination of two or more.

[0012]

The present invention will be described below with reference to examples. In the examples, parts and% represent parts by weight and% by weight, respectively. (1) Production of unsaturated polyester resin (A) A 2 liter four-necked flask equipped with a stirrer, a condenser, a nitrogen gas introducing tube and a thermometer was charged with 380 parts of propylene glycol, 624 parts of neopentyl glycol and 747 parts of isophthalic acid. After charging, the temperature was raised to 150 ° C. in 1 hour using a mantle heater while slowly flowing nitrogen gas, and further raised to 220 ° C. in 6 hours. The temperature was kept for 5 hours to obtain an intermediate having an acid value of 8. After cooling, 539 parts of maleic anhydride was charged therein, the temperature was raised to 150 ° C. in 1 hour, and the temperature was raised to 210 ° C. in 4 hours. The reaction was allowed to proceed while keeping the temperature at that temperature to obtain an unsaturated polyester having an acid value of 25. 60% of unsaturated polyester was added to styrene monomer in which 0.01% of hydroquinone was dissolved.
It melt | dissolved so that it might become, and the unsaturated polyester resin (A) was obtained.

(2) Manufacture of unsaturated polyester resin (B) 304 parts of propylene glycol, 456 parts of neopentyl glycol and hexahydroanhydrous in a 2-liter four-necked flask equipped with a stirrer, a condenser, a nitrogen gas introducing tube and a thermometer. Phthalic acid 493 parts, maleic anhydride 470
A portion was charged and the temperature was raised to 150 ° C. in 1 hour using a mantle heater while slowly flowing nitrogen gas, and further raised to 210 ° C. in 4 hours. Incubate at that temperature for 5 hours,
An unsaturated polyester oligomer having an acid value of 34 was obtained. This was cooled and, while maintaining the temperature at 120 ° C., 0.5 parts of quaternary ammonium salt of dimethylbenzylammonium chloride, 130 parts of glycidyl methacrylate methacrylate and 0.2 part of hydroquinone were charged and reacted for 1 hour. This was dissolved in styrene monomer in which 0.01% of hydroquinone was dissolved so that the unsaturated polyester content was 60% to obtain an unsaturated polyester resin (B).

(3) Manufacture of unsaturated polyester resin (C) 304 parts of propylene glycol and 456 parts of neopentyl glycol in a 2-liter four-necked flask equipped with a stirrer, a condenser, a nitrogen gas introducing tube and a thermometer.
Charge 550 parts of 4-cyclohexanedicarboxylic acid and use a mantle heater while slowly flowing nitrogen gas.
The temperature is raised to 150 ° C over a period of 5 hours and then 220 ° C.
The temperature was raised to. The temperature was kept for 5 hours to obtain an intermediate having an acid value of 9. After cooling, 470 parts of maleic anhydride was charged into this, the temperature was raised to 150 ° C. in 1 hour, and 2 hours were taken in 4 hours.
The temperature was raised to 10 ° C. The reaction was allowed to proceed while keeping the temperature at that temperature to obtain an unsaturated polyester oligomer having an acid value of 29. This was cooled and dissolved in styrene monomer in which 0.01% of hydroquinone was dissolved so that the content of unsaturated polyester oligomer was 70%, and the quaternary ammonium salt of dimethylbenzylammonium chloride was added while maintaining the temperature at 100 ° C.
5 parts, 130 parts of glycidyl methacrylate methacrylate and 0.2 part of hydroquinone were charged and reacted for 1 hour. Styrene monomer was added thereto so that the unsaturated polyester content was 60% to obtain an unsaturated polyester resin (C).

Examples 1 to 3 and Comparative Example 1 A glass plate having a length of 30 cm, a width of 30 cm, and a thickness of 10 mm was coated with a resin composition for gel coating prepared by the formulation shown in Table 1 by a spray gun (caliber 2.5 mm). Using thickness 0.10m
m, 0.15mm and 0.20mm to coat 5
The gel coat layer was formed by curing in a constant temperature bath at 0 ° C. for 40 minutes. Then, on this gel coat layer, 3 pieces of Nitto Boseki chopped strand mats (area weight 450 g / m ² ) of 30 × 30 cm were added to 100 parts of Polyset 5595 APT (Hitachi Chemical Co., Ltd., unsaturated polyester resin). , 8 parts of titanium oxide and 1 part of Permec N (trade name, manufactured by NOF CORPORATION, organic peroxide, 55% methyl ethyl ketone peroxide) were impregnated with the resin composition for lamination, and after curing at 50 ° C. for 40 minutes, FR by cooling and demolding
A P molded product was obtained.

The properties of the gel coat layer and the FRP molded product obtained were examined as follows, and the results are shown in Table 1. (1) Presence or absence of lifting: Visual observation was performed according to the thickness of the gel coat film. (2) Weather resistance: An accelerated test was conducted with a sunshine weatherometer (manufactured by Suga Test Instruments Co., Ltd.), and the occurrence of chalking and the color difference were examined as follows. i) Occurrence of choking: The time of occurrence of choking was confirmed by irradiating the sunshine weatherometer. ii) Color difference (△ E): 10 by sunshine weatherometer
The change in color when irradiated for 00 hours was measured with a color difference meter manufactured by Nippon Denshoku Industries Co., Ltd.

[0017]

[Table 1]

From Table 1, unsaturated polyester resin (B)
Alternatively, it is shown that excellent film-forming property and weather resistance can be obtained by using the resin composition for gel coating of the present invention containing (C).

[0019]

According to the present invention, the FRP installed outdoors
Since the deterioration of the appearance of the molded product can be prevented, it can be expected to reduce the number of molding processes, the number of repairs, and the associated cost reduction.
Further, since lifting is less likely to occur, the coating width of the gel coat can be widened and the defective rate can be reduced.

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Claims (2)

[Claims] 1. An unsaturated polyester oligomer obtained by reacting an acid component consisting of an unsaturated dibasic acid and / or its acid anhydride and a cycloalkylenedicarboxylic acid and / or its acid anhydride with a polyhydric alcohol. A gel coat resin composition comprising an unsaturated polyester obtained by adding an unsaturated epoxy compound to a terminal group and a polymerizable monomer. 2. A method for producing a molded article having a gel coat layer, which comprises forming a gel coat layer from the resin composition for gel coat according to claim 1 and forming a fiber reinforced plastic layer or a resin layer on the gel coat layer.