JPH0366719A - Resin composition for gel coat and preparation of molded product having gel coat layer - Google Patents

Abstract

PURPOSE:To provide the subject composition having excellent coating workability and film formability and giving molded products having excellent surface hardness and mar resistance by compounding a polymer having (meth) acryloyl groups at the side chains thereof, styrene (derivative) and a polyfunctional (meth)acrylic monomer in a specific ratio. CONSTITUTION:10-15 pts.wt. of a polymer having (meth)acryloyl groups at the side chains thereof, 10-60 pts.wt. of styrene (derivative) and 10-70 pts.wt. of a multifunctional (meth)acrylic monomer [e.g. trimethylolpropanetri(meth) acrylate] are compounded to provide the objective composition suitable for forming surface-protecting layers for artificial marble counters, etc. For the prevention of the surface of a molded product a fiber-reinforced plastic layer or resin layer is preferably formed on the gel coat layer using the composition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resin composition for gel coats, and more particularly to a resin composition for gel coats that has excellent film-forming properties and abrasion resistance of molded articles.

[Conventional technology]

Gel coat resin is applied to the surface of a mold to a thickness of about 0.1 to 0.5 mm and cured, and then a composition made of unsaturated polyester resin and glass fiber is laminated thereon, and then removed from the mold. After the FRPlv is carved or a composition consisting of unsaturated polyester resin and various fillers is cast,
It is demolded and made into artificial marble moldings, which are used to decorate, protect, and improve the beauty of various molded products. However, since unsaturated polyester resin is generally used as the gel coat resin, the surface hardness of the gel coat layer is low, being 3 to 4 H or less in pencil hardness, and has the disadvantage of poor scratch resistance.

For this reason, molded products that require surface hardness are coated with acrylic, silicone, or other paints called hard coat agents and cured to improve scratch resistance. However, the hard coating agent must be cured by ultraviolet rays or electron beam curing, and the irradiation equipment for these active energy rays is expensive, and the hard coating agent is applied in a film thickness of 0.1 mm or less. At present, it is not widely used because of the need to turn the entire workplace into a clean room to avoid the presence of foreign objects and dirt, and because it adds one step to the work process.

Further, as shown in Japanese Patent Application Laid-open No. 63-108055, studies have been made to harden gel coat layers by combining unsaturated polyester, styrene monomer and polyfunctional acrylic compounds. However, sufficient surface hardness of the gel coat layer has not yet been obtained.

[Problem to be solved by the invention]

An object of the present invention is to provide a gel coat resin composition that solves the problems of the prior art, has excellent coating workability and film-forming properties, and can increase the surface hardness of molded products and improve the scratch resistance. It's about doing.

[Means to solve the problem]

The present invention provides an acryloyl group or a methacryloyl group (hereinafter referred to as
10 to 50 parts by weight of a polymer having (simply abbreviated as (meth)acryloyl group), (B) 10 to 60 parts by weight of styrene or a styrene derivative, and (C) a polyfunctional acrylic monomer or polyfunctional methacrylic monomer (hereinafter referred to as (simply abbreviated as (meth)acrylic monomer) is 10 to 70
The present invention relates to a resin composition for a gel coat comprising parts by weight, and a method for producing a molded article having a gel coat layer using the resin composition for a gel coat.

The polymer (A) having a (meth)acryloyl group in the side chain used in the present invention is composed of a polymerizable monomer (1) forming the main chain of the polymer, a functional group for introducing a (meth)acryloyl group, and a polymerizable double A polymerizable monomer (2) having a bond, and a compound (3) having a (meth)acryloyl group and a reactive group that reacts with the functional group of the polymerizable monomer (2).
Obtained by reacting with.

The polymerizable monomers (1) and (2) preferably have a homopolymer of each monomer having a glass transition temperature of 20'C or higher, from the viewpoint of improving the hardness of the reaction product.

As the polymerization monomer (1) forming the main chain of the polymer, c.
Examples include evastyrene, vinyltoluene, chlorostyrene, acrylic esters, methacrylic esters, acrylonitrile, vinyl chloride, vinyl acetate, and the like.

Examples of the polymerizable monomer (2) having a functional group for introducing a (meth)acryloyl group and a polymerizable double bond include acrylic acid, methacrylic acid, maleic anhydride, itaconic anhydride, 2-hydroxyethyl acrylate, 2-hydroxy Ethyl methacrylate, glycidyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, etc. are used.

The compound (3) having a (meth)acryloyl group and a reactive group that reacts with the functional group of the polymerizable monomer (2) is a compound (3) having a (meth)acryloyl group and reacting with the functional group of the monomer (2).
) may be used, as long as it reacts with the functional group of (meth)acryloyl group among the polymerizable monomers (2), or a reaction product of a diisocyanate and an unsaturated alcohol having a (meth)acryloyl group. Compounds in which NGO groups remain are used.

The above reaction includes (1) a method in which a polymer having an acid anhydride structure in the main chain is reacted with an alcohol having a (meth)acryloyl group, and (2) a method in which a polymer having an OH group in the main chain is reacted with an isocyanate group in the molecule. A method of reacting with an unsaturated isocyanate compound containing a (meth)acryloyl group, (3
) This can be carried out by a method in which a polymer having a carboxyl group in the main chain is reacted with an epoxy compound having a (meth)acryloyl group. Of these methods,
From the viewpoint of improving the discoloration and hardness of the obtained polymer, (1
) and (3) are preferred.

(A), (B) and (C) in the present invention include:
The parts by weight within the above range are used so that the total weight is 100 parts by weight.

The polymer (A) having a (meth)acryloyl group in its side chain is used in an amount of 10 to 50 parts by weight.

If the amount used is less than 10 parts by weight, the curability, film-forming properties and thixotropy of the composition will be reduced, and if it exceeds 50 parts by weight, the viscosity of the composition will be high and workability will be poor.

Styrene and styrene derivatives (B
) include styrene, vinyltoluene, α-methylstyrene, chlorostyrene, divinylbenzene, and the like. = styrene and styrene derivatives are 10-
It is used in a range of 60 parts by weight. If the amount used is less than 10 parts by weight, the viscosity of the composition will become too high and the curability and chemical resistance will decrease. Moreover, if it exceeds 60 parts by weight, a highly hard film cannot be obtained.

(Meth)acrylic monomer (C) used in the present invention
They include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, trimethylolmethane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta (meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1°6 hexanediol di(meth)acrylate, 1°3 butanediol di(meth)acrylate Examples include acrylate, diethylene glycol di(meth)acrylate, and the like. These may be used in combination.

The monomer (C) is used in an amount of 10 to 70 parts by weight. If the amount used is less than 10 parts by weight, a highly hard film will not be obtained, and if it exceeds 70 parts by weight, workability will be poor and the coating film will be brittle and cause cracks.

Polymerization inhibitors such as hydroquinone, pyrocatechol, and 2,6-di-tert-butylvalacresol are added to the gel coat resin composition of the present invention, if necessary.
It is cured using organic peroxide catalysts such as methyl ethyl ketone peroxide, benzoyl peroxide, cumene hydroperoxide, and lauroyl peroxide.

In this case, metal soaps such as cobalt naphthenate and cobalt octenoate, quaternary ammonium salts such as dimethylbenzylammonium chloride, β-diketones such as acetylacetone, dimethylaniline, N-ethyl metatoluidine, triethanol, etc. A curing accelerator such as amines such as amines can be used in combination.

The composition of the present invention comprises a photopolymerization initiator, such as diphenyl disulfide, benzoin, benzoin methyl ether,
Benzoin ethyl ether, benzoin-n-propyl ether, benzoin isopropyl ether, benzoin-5ec-7'thyl ether, benzoin-2-pentyl ether, benzoin cyclohexyl ether,
Photocuring can also be carried out using dimethylbenzyl ketal or the like. These photopolymerization initiators and the organic peroxide may be used in combination.

The composition of the present invention may also contain dyes, plasticizers,
In addition to ultraviolet absorbers, various additives and additives such as silica powder, asbestos powder, hydrogenated castor oil, fatty acid amide, and other known thixotropic agents, fillers, stabilizers, antifoaming agents, and leveling agents are blended. You can.

A gel coat layer is formed by a known method using the gel coat resin composition of the present invention, and a fiber reinforced plastic layer or a resin layer is formed thereon to obtain a molded article having a gel coat layer.

A resin composition containing a curing agent, filler, etc. is used as the resin layer.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

Note that parts in the examples mean parts by weight.

Examples 1.2 and 3 1) Synthesis of polymer (A) having (meth)acryloyl group in the side chain containing styrene (B) If equipped with a stirrer, reflux condenser, thermometer, gas introduction tube and dropping funnel 400 toluene in a Yotsuro flask
methyl methacrylate 3 and 1.0 g of azobisisobutylnitrile at 100°C under a nitrogen gas stream.
00g, 104g styrene and 98g maleic anhydride
A mixed solution of was added dropwise. After finishing the dripping and keeping it warm for 6 hours,
0.1 g of hydroquinone was added and kept warm for 2 hours.

Next, 130 g of 2-hydroxyethyl methacrylate and 1.5 g of dibutyltin oxide were added, and the mixture was heated at 110°.
The mixture was heated at C for 5 hours.

Next, change the reflux condenser to a fractionation condenser to distill out 200 g of toluene, add 270 g of styrene to this, and reduce the temperature inside the flask to 70'C under reduced pressure of about 200 asHg.
Toluene was selectively distilled out while maintaining the temperature. The obtained distillate is referred to as Resin A.

2) Formation of Gel Coat Layer and Evaluation of Physical Properties of Coating Film Using the obtained resin A, a resin composition for gel coat was prepared with the formulation and amount shown in Table 1.

To 100 parts of the gel coat resin composition, 2.5 parts of Aerosil #200 (silica powder, manufactured by Nippon Aerosil Co., Ltd.) and 0.1 part of cobalt naphthenate (metal content 6% by weight) were added to prepare a gel coat resin, and gel coat resin 1
Permec N (55% by weight methyl ethyl ketone peroxide, manufactured by NOF Corporation) as a curing catalyst.
After adding and mixing 1.0 parts, a film thickness of 0.2-0.
The glass was temporarily coated to a thickness of 3 m. This is 60°C
After curing for 2 hours, it was allowed to cool to room temperature. An unsaturated polyester resin (Polyset 5595APT) was applied on the resulting film.
, manufactured by Hitachi Chemical Co., Ltd.) and glass fibers to form a glass fiber-reinforced plastic layer, and after curing, the mold was removed from the glass plate to obtain a molded product having a gel coat resin layer.

The physical properties of the gel coat layer of this molded article were investigated, and the results are shown in Table 1.

The viscosity and thixotropy were measured for the gel coat resin, and the others were measured for the gel coat resin with a curing agent added or the molded product. Table 2 shows (3) Pencil hardness: According to JIS K5400 paint general test method.

(4) Scratch hardness: Based on the Japanese Agricultural Standards (Ministry of Agriculture and Forestry Notification No. 1373) (the same applies below).

Examples 4.5 and 6 1) Synthesis of polymer (A) having (meth)acryloyl group in side chain containing styrene (B) 11 equipped with a stirrer, reflux condenser, thermometer, gas introduction tube and dropping funnel 400 toluene in a Yotsuro flask
g and azobisisobutylnitrile (1.0 g), and methyl methacrylate (methyl methacrylate) 3 was prepared at 100"C under a nitrogen gas stream.
A mixed solution of 00 g and 86 g of methacrylic acid was added dropwise.
After the completion of dripping, after keeping warm for 6 hours, add hydroquinone 0.1
g was added and kept warm for 2 hours.

Next, 142 g of glycidyl methacrylate and 0.5 g of dimethylbenzyldodecylammonium chloride were added and heated at 110°C for 5 hours.

Next, the reflux condenser was changed to a fractional distillation condenser to distill out 200 g of toluene, and 220 g of styrene was added thereto, and toluene was selectively distilled off under reduced pressure of about 200 saHg while maintaining the temperature inside the flask at 70°C. The obtained distillate is referred to as resin B.

2) Formation of Gel Coat Layer and Evaluation of Physical Properties of Coating Film Using the obtained resin B, a resin composition for gel coat was prepared with the formulation and amount shown in Table 2.

To 100 parts of the gel coat resin composition, 2.5 parts of Aerosil #200 (silica powder, manufactured by Nippon Aerosil Co., Ltd.) and 0.1 part of cobalt naphthenate (metal content 6% by weight) were added to prepare a gel coat resin, Furthermore, gel coat resin 1
00 parts, Vermec N (55% by weight methyl ethyl ketone peroxide, manufactured by NOF Corporation) was added as a curing catalyst.
After adding 1.0 parts of and mixing, use a spray gun with a diameter of 3 nn and apply an air pressure of 4 KG/d to a film thickness of 0.2 to 0.3 fi.
It was applied to a glass plate so that the amount of the solution was 1. This is 60'C
After curing for 2 hours, it was allowed to cool to room temperature. An unsaturated polyester resin (Polyset 5595APT) was applied on the resulting film.
After molding and curing a glass fiber-reinforced plastic layer using glass fibers (manufactured by Hitachi Chemical Co., Ltd.) and glass fibers, the molded product was removed from the glass plate to obtain a molded product having a gel coat resin layer.

The physical properties of the gel coat layer of this molded article were investigated, and the results are shown in Table 2.

Table 2 [Effects of the Invention] The gel coat resin m-acid of the present invention has excellent coating workability and film-forming properties, and can be coated and cured under the same conditions as conventional gel coat resin compositions.
Excellent surface hardness of the molded product can be obtained, and scratch resistance can be improved. The composition of the present invention is useful for forming surface protective layers of artificial marble counters, FRP molded products, and the like.

Claims (1)

Scope of Claims 1. (A) 10 to 50 parts by weight of a polymer having an acryloyl group or methacryloyl group in the side chain so that the total weight is 100 parts by weight; (B) 10 to 50 parts by weight of styrene or a styrene derivative; 60 parts by weight, and (C) a resin composition for gel coat comprising 10 to 70 parts by weight of a polyfunctional acrylic monomer or a polyfunctional methacrylic monomer. 2. A method for producing a molded article having a gel coat layer, in which the gel coat layer is molded using the gel coat resin composition according to claim 1, and a fiber-reinforced plastic layer or a resin layer is formed thereon.