JP2002121425A - Resin composition for gel coat and method for producing molding using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin composition for a gel coat comprising a (meth) acrylic polymer and a monomer component, capable of sufficiently improving both of formation characteristics in formation of a gel coat layer by coating especially with a spray and properties of the gel coat layer after the formation. SOLUTION: This resin composition for a gel coat comprises a resin component composed of a polymer and a monomer as a main component. When the amount of the resin component is 100 wt.%, 5-<=30 wt.% of the component A of a (meth)acrylic polymer, 20-<=60 wt.% of the component B of methyl methacrylate and 30-<=70 wt.% of the component C of a high-boiling monomer having >=140 deg.C boiling point are contained in the resin component. Consequently both formation characteristics of the gel coat layer and properties of the gel coat layer can be sufficiently improved.

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 a gel coat suitably used for a gel coat formed as an outer layer in order to improve the surface characteristics of a molded article, and a method for producing a molded article using the same. And especially (meta)
The present invention relates to a gel coat resin composition which contains an acrylic polymer, is excellent in sprayability when forming a gel coat, and can improve the physical properties of the obtained gel coat layer, and a method for producing a molded article using the same. It is.

[0002]

2. Description of the Related Art Conventionally, a gel coat is a resin layer formed as an outer layer on the surface of various molded articles, and has excellent design properties, moldability, or chemical, physical, mechanical, and electrical properties. It is used for various purposes to have. Its main uses are bathtubs, unit baths, boats, fishing boats,
There are FRP applications such as tanks, vehicles, housings, etc., and non-FRP applications such as artificial marble molded products that improve the decoration, protection and aesthetics of various molded products by utilizing their high designability and moldability.

[0003] The gel coat is formed into a film (gel coat layer) by coating a resin composition for gel coating, usually by spray coating. Here, generally, in the painting process,
Bubbles remain on the gel coat layer and cracks (interface) on the surface
It is not preferable that unevenness occurs. Therefore, the resin composition for gel coating is required to have various physical properties such as bubble removal properties in which bubbles disappear immediately upon spray coating and film-forming properties in which the surface is smooth without cracks. Particularly, in order to form a high quality gel coat layer, film forming properties are very important physical properties.

[0004] However, for example, in exterior wall painting, etc.
This is not the case in applications in which foams, cracks, irregularities, etc. are intentionally formed to give the surface a unique decorativeness or aesthetics.

Further, in order to produce a molded article having a gel coat layer using the resin composition for gel coat, it is necessary to cure the previously formed gel coat layer in a state called tack-free (not completely cured but until there is no stickiness). ), And then a back layer such as artificial marble or fiber reinforced plastic (FRP) must be laminated. If the gel coat layer is not tack-free, the uniform state of the gel coat layer is disturbed due to the curing shrinkage after the formation of the back layer, and the quality of the gel coat layer is greatly reduced.

[0006] Therefore, if the time required to reach tack-free after the application of the gel coat resin composition is long, the production efficiency of the gel coat layer and the molded article provided with the gel coat layer will be reduced. Is also required to be tack-free.

[0007] In other words, the resin composition for gel coating is required to have two large forming characteristics in forming the gel coat layer, that is, spraying properties including film forming properties and bubble removal properties, and tack-free properties.

[0008] In addition, the gel coat layer formed from the above-mentioned gel coat resin composition has an appropriate surface hardness (scratch resistance), heat resistance, water resistance, solvent resistance, and / or Also, various physical properties such as durability properties such as weather resistance (hereinafter referred to as physical properties after formation) are required.

As the resin contained in the resin composition for gel coating, an unsaturated polyester resin is used in the conventional general technology. However, this unsaturated polyester resin does not provide sufficient surface hardness when a gel coat layer is formed, and is inferior in abrasion resistance characteristics.In addition, in some situations, even the durability characteristics may be impaired, and the physical properties after formation are insufficient. There is a problem that there is.

[0010] Therefore, a technique relating to a resin composition for gel coating without using an unsaturated polyester resin has been proposed. Specifically, for example, there are various techniques disclosed in JP-A-3-66719 and JP-A-6-155664.

In the first technique, as a resin composition for gel coating, a resin composition containing a polymer having a (meth) acryloyl group in a side chain, styrene or a styrene derivative, and a polyfunctional (meth) acrylic monomer is used. Used. In another technique, an acrylic syrup, a curing agent (radical polymerization initiator), and a thickener (polyvalent metal oxide) are used to produce a (meth) acrylic resin material sheet that can be used for compressed air and / or vacuum forming. , A hydroxide and a polyvalent isocyanate compound) to form a gel coat layer.

[0012] In the above-mentioned technique relating to the resin composition for gel coating, the type and the content of the monomer component contained in addition to the resin are particularly considered from the viewpoint of improving the formation characteristics. Also needs to be appropriately selected. For example, the above technique discloses the use of a polyfunctional (meth) acrylic monomer as a monomer component and styrene and a derivative thereof as a monofunctional monomer. It discloses the use of monofunctional (monofunctional) (meth) acrylic monomers and crosslinkable polyfunctional monomers as components.

[0013]

However, the above-mentioned conventional technique has a problem that it is not possible to sufficiently improve both the forming characteristics of the resin composition for gel coating and the physical properties after forming the gel coating layer. ing.

For example, in the above technique, although a certain surface hardness can be ensured, it cannot be said that the surface hardness of the obtained gel coat layer is sufficiently improved. In addition, in this technique, the main purpose is to improve the surface hardness and the forming characteristics among the physical properties after formation, so that the durability properties among the physical properties after formation are extremely low. Furthermore, in this technique, depending on the monomer component contained in the resin composition, the film-forming property may be lacking, and further no improvement in tack-free property is disclosed. I can't say that.

Further, in the above-mentioned technique, the gel coat layer is not formed by a general spray method, and there is no disclosure or suggestion of improvement in sprayability. Furthermore, in this technique, since the gel coat layer is thickened by a thickener such as MgO and then the back layer is laminated, it is different from the general manufacturing method of a molded article having a gel coat layer, and has a tack-free property. There is no need to improve. That is, with the monomer component contained in the resin composition of this technique, neither the spray property nor the tack-free property can be sufficiently improved, and the forming properties are insufficient. Further, the physical properties after formation are not sufficiently improved.

In recent years, in the resin composition for gel coating, from the viewpoint that the obtained gel coating shows excellent physical properties,
As a resin to be used, instead of the unsaturated polyester resin, a (meth) acrylic resin ((meth) acrylic syrup) containing a (meth) acrylic polymer and a (meth) acrylic monomer has attracted attention. . However, in a conventional resin composition for gel coating using a (meth) acrylic resin ((meth) acrylic syrup), it was not known at all to sufficiently improve both the forming properties and the physical properties after forming the gel coat. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide both the formation characteristics when forming a gel coat layer, particularly by spray coating, and various physical properties of the gel coat layer after formation. It is an object of the present invention to provide a gel coat resin composition capable of sufficiently improving the viscosity, and a method for producing a molded article using the same.

[0018]

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, as a component of the resin composition for gel coating, a (meth) acrylic polymer, methyl methacrylate and By using a high-boiling monomer having a boiling point of 140 ° C. or higher, it is possible to sufficiently improve both the formation characteristics when forming a gel coat layer by coating and various physical properties of the gel coat layer after formation, and The present inventors have found that a molded article having a quality gel coat can be manufactured, and have completed the present invention.

That is, the resin composition for gel coating according to the present invention is used for a gel coating formed as an outer layer on the surface of a molded product, and comprises a resin component comprising a polymer and a monomer, in order to solve the above-mentioned problems. When the resin component is 100% by weight, component A: (meth) acrylic polymer is in the range of 5% by weight or more and 30% by weight or less as a polymer in the resin component. And as a monomer, component B: methyl methacrylate in the range of 20% by weight or more and 60% by weight or less, and component C: 30% by weight of a high boiling monomer having a boiling point of 140 ° C. or more. It is characterized in that it is contained within the range of 70% by weight or less.

Further, the above component C: a high-boiling monomer includes:
When the component C is 100% by weight, it is preferable that the polyfunctional monomer is further contained in a range of 1% by weight or more and 50% by weight or less. It is more preferred that the union has a polymerizable double bond in the molecule, and the curing agent has a 10-hour half-life of 80 hours.
It is particularly preferable that an organic peroxide having a temperature of not higher than ° C is contained.

According to the above-mentioned constitution, by using the component C: a monomer having a high boiling point within the above range, it is possible to ensure a very excellent spraying property, and further, the component B: a methyl methacrylate (M
By using MA) within the above range, it is possible to improve the tack-free property by shortening the time until the gel coat is tack-free and to improve the physical properties after molding without impairing the spray property. In addition, the physical properties of the gel coat layer after formation become very excellent by using the component A: (meth) acrylic polymer.

Further, when the above components A, B and C are contained within the above range, only the above-mentioned organic peroxide is used as a curing agent, and it is not necessary to substantially use a curing accelerator.
Therefore, it is possible to avoid undesired coloring and deterioration in physical properties after formation of the cured gel coat layer by using a general curing accelerator, and to form a gel coat layer of excellent quality very efficiently. can do.

The method for producing a molded article according to the present invention comprises a gel coat layer forming step of applying the above gel coat resin composition to a mold, a gel coat layer curing step of curing the applied gel coat layer to a tack-free state, A laminating step of forming a back layer on the gel coat layer after the gel coat layer curing step.

According to the above method, after the gel coat is first cured to tack-free, a back layer such as a fiber reinforced plastic layer or an artificial marble layer is laminated on the gel coat layer. Here, the resin composition for gel coating is not only excellent in sprayability but also excellent in tack-free property as described above, so that the tack-free time in the gel coat layer curing step can be shortened. That is, it is possible to shorten the time required for performing the laminating step after the gel coat forming step as compared with the related art, thereby improving the manufacturing efficiency of the molded article having the gel coat layer.

Hereinafter, the present invention will be described in detail.

The resin composition for gel coating according to the present invention contains a resin component as a main component as described above,
The resin component contains the above component A: (meth) acrylic polymer, component B: methyl methacrylate (MMA), and component C: high boiling monomer having a boiling point of 140 ° C. or higher.

The term "main component" as used herein means that the resin component (see below) in the gel coating resin composition is in a range of 50% by weight or more and 100% by weight or less, preferably 60% by weight or less.
% By weight to 100% by weight, more preferably 70% by weight to 100% by weight, still more preferably 80% by weight to 100% by weight, and particularly preferably 90% by weight. It means that it is contained within the range of 100% by weight or less.

In the following description, a component composed of a polymer and a monomer will be referred to as a “resin component”, and the resin component is a component in which the above components A, B and C are essential. is there. Further, the composition of the components A to C in the resin composition for gel coating according to the present invention is represented by “% by weight” as “content” contained in the resin component. In the following description, the resin composition for gel coating may be simply referred to as a resin composition.

Further, the resin component contained in the resin composition for gel coating according to the present invention comprises the above component A, component B,
And the component C are essential, but other polymers and monomers (other polymers) may be used as long as the functions and effects of the resin composition for gel coating according to the present invention and the method for producing a molded article using the same are not hindered. Coalesce or other monomer)
Can be included.

The content of the other polymer or other monomer is in the range of 0 to 20% by weight, preferably 0 to 10% by weight, based on 100% by weight of the resin component.
% By weight, and more preferably within a range from 0% by weight to 5% by weight.

That is, in the resin composition according to the present invention, the total content of the components A, B, and C in the resin component is 80% by weight to 100% by weight.
Each component is blended so as to be within the following range. Preferably, the total content of the components A, B and C is 90%.
Each component is blended so as to be in the range of not less than 100% by weight and more preferably not more than 100% by weight.

The component A: (meth) acrylic polymer used in the resin composition for gel coating according to the present invention may be a crosslinkable or non-crosslinkable (meth) acrylic polymer.

The non-crosslinkable (meth) acrylic polymer is not particularly limited. For example, the polymer may be obtained by polymerizing a (meth) acrylic acid ester and, if necessary, other monomers. Obtained ones are listed. Examples of the other monomers include a carboxyl group-containing monomer, but this is not particularly limited.

The crosslinkable (meth) acrylic polymer is not particularly limited. For example, a polymerizable polymer may be prepared by using an unsaturated epoxy compound with respect to a (meth) acrylic polymer having a carboxyl group. (Meth) acrylic polymer obtained by introducing a polymerizable double bond using unsaturated acid to (meth) acrylic polymer having a heavy bond and (meth) acrylic polymer having a glycidyl group Polymers.

As the above (meth) acrylate used for the polymerization of the above (meth) acrylic polymer, specifically, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl ( Meth) acrylate, n-butyl (meth) acrylate,
Isobutyl (meth) acrylate, t-butyl (meth)
(Meth) acrylic acid alkyl esters such as acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate; (meth) acrylic acid cycloalkyl esters such as cyclohexyl (meth) acrylate; dimethylaminoethyl (meth) acrylate, diethylamino Basic (meth) acrylates such as ethyl (meth) acrylate; and the like, but are not particularly limited. These (meth) acrylates may be used alone or in combination of two or more.

Of the above-listed compounds, methyl methacrylate, ie, methyl methacrylate (MMA), and (meth) acrylate esters containing methyl methacrylate as a main component are particularly preferred. By using methyl methacrylate as a main component, various post-formation physical properties such as weather resistance, transparency, surface gloss, and surface hardness of the gel coat,
Appearance, safety, etc. can be further improved.

When a basic (meth) acrylate is used as the (meth) acrylate,
It is preferable to polymerize using a neutral (meth) acrylate at 100% by weight or more based on the basic (meth) acrylate. Examples of the neutral (meth) acrylate include the above-mentioned alkyl (meth) acrylate and cycloalkyl (meth) acrylate.

The other monomer may be any compound having a polymerizable double bond, and is not particularly limited. In the present invention, a crosslinkable (meth) acrylic polymer is obtained. Therefore, a monomer having a cross-linking structure, such as a monomer having a carboxyl group or a monomer having a glycidyl group, which will be described later, can be used as another monomer.

That is, in the (meth) acrylic resin composition according to the present invention, it is more preferable to use a crosslinkable (meth) acrylic polymer as the component A. By using a cross-linkable one, durability properties such as solvent resistance and weather resistance among the physical properties after formation are further improved as compared with a case where a non-cross-linkable one is used.

Therefore, in the present invention, the crosslinkable (meth)
In order to obtain an acrylic polymer, for example, a (meth) acrylic polymer having a carboxyl group is obtained, and then a polymerizable double polymer is added to the (meth) acrylic polymer using an unsaturated epoxy compound. After introducing a bond or obtaining a (meth) acrylic polymer having a glycidyl group, a polymerizable double bond is introduced into the (meth) acrylic polymer using an unsaturated acid. . The crosslinkable (meth) acrylic polymer is not limited to these.

The (meth) acrylic polymer having a carboxyl group is a monomer component containing a (meth) acrylic acid ester and a monomer having a carboxyl group (hereinafter referred to as a monomer component).
(Hereinafter simply referred to as a monomer component).

The monomer having a carboxyl group (hereinafter, referred to as a carboxyl group-containing monomer) may be any compound as long as it has a polymerizable double bond and a carboxyl group in the molecule. Not something. As the carboxyl group-containing monomer, specifically, for example,
Unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid and vinylbenzoic acid; unsaturated dicarboxylic acids such as maleic acid, fumaric acid, itaconic acid and citraconic acid; monoesters of these unsaturated dicarboxylic acids; And a long-chain carboxyl group-containing monomer such as a monoester. Examples of the monoester of the unsaturated dicarboxylic acid include, for example, monomethyl maleate, monoethyl maleate, monobutyl maleate, monooctyl maleate, monomethyl fumarate, monoethyl fumarate, monobutyl fumarate, monooctyl fumarate, citracone Monoethyl acid and the like.
Examples of the acid anhydride monoester include succinic acid monoester, phthalic acid monoester, and hexaphthalic acid monoester. One of these carboxyl group-containing monomers may be used alone, or two or more thereof may be used in combination.

The long-chain carboxyl group-containing monomer is
The (meth) acrylic acid ester having a hydroxyl group is obtained by esterifying the hydroxyl group with an acid anhydride. Specific examples of the above acid anhydride include succinic anhydride, phthalic anhydride, hexahydrophthalic anhydride and the like. Examples of the (meth) acrylate having a hydroxyl group include 2-hydroxyethyl (meth) acrylate,
An ε-caprolactone ring-opening adduct to -hydroxyethyl (meth) acrylate or a γ-butyrolactone ring-opening adduct to 2-hydroxyethyl (meth) acrylate can be used.

The amount of the carboxyl group-containing monomer to be used is not particularly limited, but when a crosslinkable (meth) acrylic polymer is obtained, 0.5% by weight to 0.5% by weight of the monomer component.
More preferably in the range of 50% by weight, even more preferably in the range of 1% to 20% by weight,
It is particularly preferred that it is in the range of 3% by weight to 10% by weight.

When the amount of the carboxyl group-containing monomer used is 0.
If the amount is less than 5% by weight, the number of polymerizable double bonds that can be introduced by reacting a carboxyl group-containing (meth) acrylic polymer with an unsaturated epoxy compound is limited. Therefore, the physical properties such as the strength at the time of heating of the obtained gel coat may be reduced. If the amount of the carboxyl group-containing monomer exceeds 50% by weight, the obtained gel coat may have reduced weather resistance and water resistance.

The above monomer component contains a vinyl compound (monomer) containing no carboxyl group as required. The vinyl compound is not particularly limited as long as it is a compound having a polymerizable double bond. As the vinyl compound, specifically, for example,
Styrene monomers such as styrene, α-methylstyrene, vinyltoluene and chlorostyrene; vinyl esters such as vinyl acetate; allyl compounds such as allyl alcohol, ethylene glycol monoallyl ether and propylene glycol monoallyl ether; (meth) acrylamide (Meth) acrylonitrile; N-alkoxy-substituted (meth) acrylamide such as N-methoxymethylacrylamide and N-ethoxymethylacrylamide; unsaturated basic monomer; N-phenylmaleimide, N-cyclohexylmaleimide, N-isopropylmaleimide And maleimide monomers. These vinyl compounds, if necessary, may be used alone,
Further, two or more kinds may be used in combination.

When the vinyl compound is mixed with the (meth) acrylic acid ester, the mixing ratio of the two, that is,
The content of the vinyl compound in the monomer component depends on the type of the vinyl compound and the combination with the (meth) acrylate, but is preferably 50% by weight or less.

When polymerizing the above monomer components, it is desirable to use a polymerization initiator. Specific examples of the polymerization initiator include azo compounds such as 2,2′-azobisisobutyronitrile and 2-phenylazo-2,4-dimethyl-4-methoxyvaleronitrile. However, there is no particular limitation. One of these polymerization initiators may be used alone, or two or more thereof may be used in combination. The amount of the polymerization initiator to be added to the monomer component is not particularly limited.

When the above monomer component is polymerized, it is more desirable to add a chain transfer agent to the monomer component in order to adjust the average molecular weight and the like of the polymer. The above chain transfer agent is not particularly limited, but a thiol compound is most suitable since the polymerization reaction of the monomer component can be controlled very easily. Specific examples of the thiol compound include alkyl mercaptans such as t-butyl mercaptan, n-octyl mercaptan, and n-dodecyl mercaptan; aromatic mercaptans such as thiophenol and thionaphthol; thioglycolic acid; Octyl acid, ethylene glycol dithioglycolate, trimethylolpropane tris- (thioglycolate), thioglycolic acid alkyl esters such as pentaerythritol tetrakis- (thioglycolate); β-mercaptopropionic acid; β-mercaptopropionic acid octyl, 1,4-butanediol di (β-thiopropionate), trimethylolpropane tris-
(Β-thiopropionate), β-mercaptopropionic acid alkyl esters such as pentaerythritol tetrakis- (β-thiopropionate); and the like, but are not particularly limited thereto. One of these chain transfer agents may be used alone, or two or more thereof may be used in combination. Note that, as the chain transfer agent, α-methylstyrene dimer, carbon tetrachloride, or the like can also be used.

The amount of the chain transfer agent to be used may be set according to the kind of the chain transfer agent, the combination with the (meth) acrylic acid ester and the like, and is not particularly limited. It is preferable that the amount is in the range of 0.1% by weight to 15% by weight based on the body component.

Examples of the polymerization method of the above monomer components include bulk polymerization (bulk polymerization), solution polymerization, suspension polymerization,
Known polymerization methods such as emulsion polymerization can be employed. For example, when suspension polymerization is employed, the monomer component may be suspended in a dispersion medium such as water using a dispersion stabilizer such as polyvinyl alcohol. Reaction conditions such as a reaction temperature and a reaction time for performing the above polymerization are not particularly limited, and for example, known reaction conditions can be adopted. Note that the above polymerization is more preferably performed in an atmosphere of an inert gas such as nitrogen gas.

By the above method, a reaction mixture containing a carboxyl group-containing (meth) acrylic polymer (non-crosslinkable) can be obtained. The average molecular weight of the carboxyl group-containing (meth) acrylic polymer is such that the weight average molecular weight (Mw) is
6.0 × 10 ³ to 1.0 × 10 ⁶ , number average molecular weight (Mn)
It is particularly preferably about 3.0 × 10 ³ to 5.0 × 10 ⁵ , but is not particularly limited.

The (meth) acrylic polymer having a glycidyl group can be obtained by polymerizing a monomer component containing a (meth) acrylate and a monomer having a glycidyl group. The monomer having a glycidyl group (hereinafter, referred to as a glycidyl group-containing monomer) may be a compound having a polymerizable double bond and a glycidyl group in a molecule, and is not particularly limited. Absent. Examples of the glycidyl group-containing monomer include the aforementioned unsaturated epoxy compounds.

The method for producing the glycidyl group-containing (meth) acrylic polymer and the reaction conditions thereof may be the same as the method for producing the carboxyl group-containing (meth) acrylic polymer described above and the reaction conditions.

The crosslinkable (meth) acrylic polymer in the present invention is obtained by introducing a polymerizable double bond into the carboxyl group-containing (meth) acrylic polymer using the unsaturated epoxy compound (a). Or (b) reacting the glycidyl group of the glycidyl group-containing (meth) acrylic polymer with the carboxyl group of the unsaturated acid (the glycidyl group is subjected to a ring-opening reaction). Are preferably used.

The unsaturated epoxy compound used in the above method (a) includes a carboxyl group-containing (meth) compound.
The compound is not particularly limited as long as it is a compound having an epoxy group capable of reacting with the carboxyl group of the acrylic monomer and a polymerizable double bond. Specific examples of the unsaturated epoxy compound include allyl glycidyl ether; glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate; and mono (meth) acrylate of epoxy resin.
These compounds may be used alone or in combination of two or more.

The amount of the unsaturated epoxy compound to be used may be set according to the kind of the unsaturated epoxy compound or the combination with the carboxyl group-containing (meth) acrylic polymer, and is not particularly limited. Is from 0.5 times mol to the carboxyl group-containing monomer used as a raw material of the carboxyl group-containing (meth) acrylic polymer.
It is more preferably in the range of 2 moles, and 0.8 mole to 1.
More preferably, it is within a range of 5 moles.

The catalyst for promoting the introduction of a polymerizable double bond into a carboxyl group-containing (meth) acrylic polymer using the above unsaturated epoxy compound is not particularly limited, but specific catalysts may be used. Include, for example, Zn, S
Examples include a catalyst containing at least one element selected from the group consisting of n and Zr, or a quaternary phosphonium salt. A method for introducing a polymerizable double bond using these catalysts will be described in a method for producing a crosslinkable (meth) acryl syrup described later.

Examples of the unsaturated acid used in the method (b) include a carboxyl group capable of reacting with the glycidyl group of the glycidyl group-containing (meth) acrylic polymer;
Any compound having a polymerizable double bond may be used, and there is no particular limitation. Examples of the unsaturated acid include the carboxyl group-containing monomers described above. The reaction conditions for the ring opening reaction of the glycidyl group are the same as the reaction conditions for the esterification reaction between the carboxyl group-containing (meth) acrylic polymer and the unsaturated epoxy compound.

The double bond equivalent of the crosslinkable (meth) acrylic polymer, that is, the molecular weight per polymerizable double bond is preferably in the range of 2.0 × 10 ² to 1.0 × 10 ^5. , More preferably in the range of 1.0 × 10 ³ to 1.0 × 10 ⁴ , most preferably in the range of 2.0 × 10 ³ to 8.0 × 10 ³ .

The double bond equivalent is determined by “molecular weight of (meth) acrylic polymer / number of polymerizable double bonds contained in one molecule of the polymer”. By setting the double bond equivalent of the (meth) acrylic polymer within the above range,
The post-formation properties such as solvent resistance of a gel coat formed using the resin composition according to the present invention can be improved.

If the double bond equivalent of the (meth) acrylic polymer is less than 2.0 × 10 ² , the resulting gel coat may have poor surface properties such as surface smoothness and gloss. On the other hand, if the double bond equivalent exceeds 1.0 × 10 ⁵ , the solvent resistance and hot strength of the gel coat may be reduced.

In the present invention, the non-crosslinkable or crosslinkable (meth) acrylic polymer may be a crosslinkable or noncrosslinkable (meth) acrylic syrup (liquid resin). That is, the (meth) acrylic syrup according to the present invention comprises the crosslinkable or non-crosslinkable (meth) acrylic polymer and another vinyl monomer.

The vinyl monomer is not particularly limited as long as it is a compound having a polymerizable double bond. Specific examples of the vinyl monomer include the above-mentioned (meth) acrylate, a carboxyl group-containing monomer, a glycidyl group-containing monomer, and a vinyl compound.

Among these compounds, alkyl methacrylate and styrene monomers are more preferred. Further, among the alkyl methacrylates, methyl methacrylate (methyl methacrylate), ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, and t-butyl methacrylate are more preferable, and methyl methacrylate (MMA) Is particularly preferred. Of the styrene monomers, styrene is particularly preferred. This MMA corresponds to Component B and styrene corresponds to Component C: high boiling monomer.

These vinyl monomers may be used alone or in combination of two or more. As a result, various post-formation physical properties such as weather resistance, transparency, and surface gloss, appearance, and safety of the obtained gel coat can be further improved.

The above-mentioned vinyl monomer may be the same as or different from the above-mentioned monomer components. A reaction mixture containing an unreacted monomer component obtained by partial polymerization of the monomer component can be suitably used as a (meth) acryl syrup. The (meth) acrylic syrup in which the vinyl monomer is different from the monomer component is prepared, for example, by mixing the (meth) acrylic polymer isolated from the reaction mixture with the vinyl monomer. Obtainable.

The ratio (ratio) of the (meth) acrylic polymer and the vinyl monomer in the (meth) acrylic syrup according to the present invention is defined assuming that the total amount of both is 100% by weight.
It is preferable to adjust the amount of the (meth) acrylic polymer to be in the range of 7% by weight to 80% by weight and the amount of the vinyl monomer to be in the range of 93% by weight to 20% by weight. If necessary, other components such as various additives may be contained in addition to the (meth) acrylic polymer and the vinyl monomer.

The method for producing the above (meth) acrylic syrup is not particularly limited, but the above-mentioned component A:
In the process of polymerizing the (meth) acrylic polymer, a method of stopping the polymerization of the monomer component in the middle, that is, a partial polymerization can be preferably used. Thereby, a (meth) acrylic polymer having a carboxyl group (carboxyl group-containing (meth) acrylic polymer),
Since a mixture with an unreacted monomer component is obtained, a (meth) acryl syrup comprising a carboxyl group-containing (meth) acrylic polymer and a monomer can be produced in one step.

The method for producing a crosslinkable (meth) acrylic syrup according to the present invention comprises the above-mentioned component A: (meth)
This will be described more specifically by taking partial polymerization of an acrylic polymer as an example.

As a specific method for producing the above-mentioned crosslinkable (meth) acrylic syrup, for example, a non-crosslinkable (meth) acrylic syrup consisting of the above-mentioned carboxyl group-containing (meth) acrylic polymer and monomer, Existence of a catalyst containing at least one element selected from the group consisting of Zn, Sn and Zr, or a quaternary phosphonium salt as a catalyst for promoting the introduction of a polymerizable double bond with a saturated epoxy compound The following reaction method can be used.

That is, the carboxyl group of the carboxyl group-containing (meth) acrylic polymer is subjected to a ring-opening reaction with the epoxy group of the unsaturated epoxy compound, that is, the carboxyl group of the (meth) acrylic polymer is subjected to an esterification reaction. A polymerizable double bond can be introduced into the group-containing (meth) acrylic polymer.

The above catalyst is an esterification catalyst, and Zn,
Metal compounds containing at least one element selected from the group consisting of Sn and Zr (hereinafter simply referred to as metal compounds), and quaternary phosphonium salts. The above metal compounds and quaternary phosphonium salts have high catalytic activity and can mainly promote the reaction between the carboxyl group of the carboxyl group-containing (meth) acrylic polymer and the unsaturated epoxy compound. That is, the catalyst can promote the introduction of a polymerizable double bond into the carboxyl group-containing (meth) acrylic polymer.

The metal compound and the quaternary phosphonium salt do not color the (meth) acrylic syrup and the resin composition according to the present invention containing the syrup. Further, by using the metal compound and the quaternary phosphonium salt, a decrease in storage stability of the (meth) acrylic resin composition caused by a conventional (general) catalyst can be suppressed.

The metal compound includes an inorganic metal compound containing at least one element selected from the group consisting of Zn, Sn and Zr, a metal oxo acid salt, a metal polyoxo acid salt, an organic metal compound, a metal organic acid salt, Metal complex salts and the like.

The inorganic metal compounds include Zn, Sn
Metal halides such as metal fluorides, metal chlorides, metal bromides, and metal iodides of at least one metal selected from the group consisting of Zr and Zr; metal chalcogenides such as metal oxides and metal sulfides; metal nitrides A metal phosphide;
Metal arsenide; metal carbide; metal silicide; metal boride; metal cyanide; metal hydroxide;
And the like, but are not particularly limited. Specific examples of the inorganic metal compound include zinc chloride, zirconium oxide, and tin sulfide.

The above oxo acid metal salts include Zn, S
a metal sulfate, a metal nitrate, a metal phosphate, a metal phosphinate, a metal phosphonate, a metal metaphosphate, a metal borate, chlorate of at least one metal selected from the group consisting of n and Zr Examples thereof include metal salts, metal bromates, metal iodates, metal silicates, but are not particularly limited. Specific examples of the oxo acid metal salt include tin sulfate, zinc phosphate, zirconium nitrate and the like. In the present invention, the oxo acid metal salt also includes a hydrogen salt such as zinc hydrogen phosphate.

The above-mentioned metal salts of polyoxo acid include Z
a metal polyphosphate or a metal polyborate of at least one metal selected from the group consisting of n, Sn and Zr;
Examples include, but are not limited to, metal polyniobate, metal polytantalate, metal polymolybdate, metal polyvanadate, metal polytungstate. As the polyoxoacid metal salt, specifically,
For example, zinc polyphosphate and the like can be mentioned.

As the organometallic compound, the following general formula (1) M- (R) _n (1) (where M is one element selected from the group consisting of Zn, Sn and Zr) , R is an organic group such as a methyl group, an ethyl group, a methoxy group, and ethoxy, and n is an integer of 1 to 6), but is not particularly limited thereto. As the organometallic compound,
Specifically, for example, diethyl zinc, tetraethoxy zirconium and the like can be mentioned.

Examples of the organic acid metal salts include metal soaps, metal acetates, metal benzoates, metal salicylates, metal oxalates, and tartaric acids of at least one metal selected from the group consisting of Zn, Sn, and Zr. Examples thereof include a metal salt, a metal lactate, and a metal citrate, but are not particularly limited. Examples of the metal soap include metal salts of fatty acids (for example, metal salts of lauric acid, metal salts of myristic acid,
Metal palmitate, metal stearate, metal oleate, etc.), metal naphthenate, metal octylate,
Metal salts of sulfonic acid, metal salts of sulfuric acid esters, metal salts of phosphoric acid esters and the like can be mentioned. Specific examples of the metal soap include zinc octylate and tin stearate. Further, specific examples of the organic acid metal salt other than the metal soap include zinc acetate and tin salicylate.

The above-mentioned metal complex salt is represented by the following general formula (2) M- (L) _n (2) (wherein M is one element selected from the group consisting of Zn, Sn and Zr; L is a ligand such as acetylacetone, and n is an integer of 1 to 6), but is not particularly limited. Specific examples of the metal complex salt include zinc acetylacetone.

Examples of the above quaternary phosphonium salts include, for example, tetraphenylphosphonium chloride, tetraphenylphosphonium bromide, tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, butyltriphenylphosphonium chloride, butyltriphenylphosphonium bromide ,
Benzyltriphenylphosphonium chloride, benzyltriphenylphosphonium bromide, tetrabutylphosphonium hydroxide and the like can be mentioned. Of the quaternary phosphonium salts exemplified above, a tetraphenylphosphonium salt is more preferable, and tetraphenylphosphonium bromide is particularly preferable because the time required for the esterification reaction can be shortened.

The quaternary phosphonium salt has a higher catalytic activity than the above various compounds containing at least one element selected from the group consisting of Zn, Sn and Zr. Therefore, by performing an esterification reaction using a quaternary phosphonium salt as a catalyst, the molecular weight distribution of a (meth) acrylic polymer having a polymerizable double bond introduced via an ester bond can be made smaller (narrower). can do.
More specifically, by performing an esterification reaction using a quaternary phosphonium salt, the d value (Mw / Mn) indicating the molecular weight distribution of the (meth) acrylic polymer falls within a range of 1 to 2. Can be adjusted.

The amount of the catalyst to be used may be determined according to the type thereof, the combination with the carboxyl group-containing (meth) acrylic polymer or the like, and is not particularly limited. If it is a metal compound, that is,
In the case of the above-mentioned various compounds, 0.1 to 100 parts by weight of the carboxyl group-containing (meth) acrylic polymer is used.
It is more preferably in the range of 005 parts by weight to 5 parts by weight,
More preferably, the amount is in the range of 05 parts by weight to 3 parts by weight. Further, (2) when the catalyst is a quaternary phosphonium salt,
The amount is more preferably 0.005 to 5 parts by weight, more preferably 0.05 to 4 parts by weight, based on 100 parts by weight of the carboxyl group-containing (meth) acrylic polymer. Particularly preferred is a range of 1 to 3 parts by weight.

In carrying out the above esterification reaction, a polymerization inhibitor may be used, if necessary. As the polymerization inhibitor, specifically, for example, hydroquinone,
Methylhydroquinone, t-butylhydroquinone, p
-Methoxyphenol and the like, but are not particularly limited. In performing the esterification reaction, a solvent can be used, if necessary. As the solvent, water and / or an organic solvent is preferable.

In the above esterification reaction, a (meth) acryl syrup comprising a carboxyl group-containing (meth) acrylic polymer and a monomer, an unsaturated epoxy compound,
The order and method of mixing the metal compound or the quaternary phosphonium salt are not particularly limited, and the metal compound or the quaternary phosphonium salt may be present during the reaction between the (meth) acrylic syrup and the unsaturated epoxy compound. Just do it.

As another method for producing the crosslinkable (meth) acrylic syrup, for example, the glycidyl group of the glycidyl group-containing (meth) acrylic polymer contained in the noncrosslinkable (meth) acrylic syrup may be used. It is obtained by reacting with a carboxyl group of a hydrating acid (ring-opening reaction of a glycidyl group).

That is, (meth) having a glycidyl group
By performing an esterification reaction between the acrylic syrup and the unsaturated acid, a polymerizable double bond can be introduced into the glycidyl group-containing (meth) acrylic polymer. As described above, the reaction conditions for the esterification reaction between the glycidyl group-containing (meth) acrylic polymer and the unsaturated acid are, for example, those of the carboxyl group-containing (meth) acrylic polymer and the unsaturated epoxy compound. Reaction conditions for the esterification reaction and the like can be applied.

The crosslinkable (meth) acrylic syrup obtained by the above-mentioned method is the above-mentioned carboxyl group-containing (meth) acrylic polymer or glycidyl group-containing (meth) acrylate.
Acrylic polymer containing polymerizable double bond (crosslinkable (meth) acrylic polymer) and vinyl monomer such as glycidyl group-containing monomer or carboxyl group-containing monomer Becomes

In the resin composition for gel coating according to the present invention, component A: (meth) acrylic polymer
The non-crosslinkable or crosslinkable (meth) acrylic polymer obtained by the above method, or these noncrosslinkable or crosslinkable (meth) acrylic syrups can be used.

The component A in the present invention is a (meth) acrylic polymer obtained by polymerizing a monomer component containing a (meth) acrylate and other monomers as described above. However, the content of the (meth) acrylate in the monomer component is not limited to crosslinkable or non-crosslinkable, but is preferably 50% by weight or more and 100% by weight or less, and 70% by weight or more. The content is more preferably 100% by weight or less, particularly preferably 80% by weight or more and 100% by weight or less.

That is, the component A used in the present invention:
The (meth) acrylic polymer is obtained by polymerizing a monomer component containing at least 50% by weight or more of a (meth) acrylic ester homopolymer or (meth) acrylic ester ( It is a copolymer of (meth) acrylate and other monomers.

In the resin composition according to the present invention, when the spraying is used as a coating method to improve the forming characteristics and when the physical properties of the obtained gel coat layer after the formation are sufficiently improved, the resin component is used. Component A in the resin component, when the content of the polymer and the monomer is 100% by weight, the content of the (meth) acrylic polymer in the resin component is in the range of 5% by weight or more and 30% by weight or less. And more preferably in the range of 10% by weight or more and 30% by weight or less.

If the content of the component A: (meth) acrylic polymer in the resin component is less than 5% by weight, the film-forming property at the time of forming a gel coat is inferior, while if it exceeds 30% by weight, Poor foam removal after applying the resin composition.

When the (meth) acrylic polymer is (meth) acrylic syrup, the (meth) acrylic polymer contains the (meth) acrylic polymer as described above. In the range of 7% to 80% by weight, the vinyl monomer is contained in the range of 93% to 20% by weight. Therefore, when preparing the resin composition according to the present invention using the (meth) acrylic syrup, the (meth) acrylic syrup may be appropriately added in consideration of the amount of the (meth) acrylic polymer. Good.

As described above, the above (meth) acrylic syrup contains the component B: methyl methacrylate,
Component C: A high boiling monomer may already be contained. In this case, the (meth) acrylic syrup itself may be regarded as the above-mentioned resin component in the present invention, and the composition is adjusted by appropriately adding components B and C according to the use of the gel coat. The resin component in the invention may be used.

The resin composition according to the present invention contains component B:
Methyl methacrylate (methyl methacrylate, MMA)
It is included. This MMA is relatively inexpensive among (meth) acrylic esters and is advantageous in terms of cost. In addition, as a monomer component added to the resin composition for gel coating, (MMA) Among the acrylic monomers, they have an excellent balance in properties.

More specifically, in order to produce a molded article having a gel coat layer using the resin composition for gel coat,
As described above, after the formed gel coat layer is tack-free, a back layer made of artificial marble, fiber reinforced plastic, or the like must be laminated. This tack-free refers to a state in which the gel coat has not been completely cured, but has been cured until there is no stickiness on the surface. When a back layer is laminated on a gel coat layer that is not tack-free, the uniformly formed gel coat layer is disturbed due to shrinkage during curing of the back layer, and the surface of the gel coat layer is `` shrinked '' called drift etc. The shape is formed.

That is, when laminating the back layer on the gel coat layer, the gel coat layer must be tack-free. However, if the time until tack-free (tack-free time) is long, the production efficiency of the molded article is greatly reduced.

In the present invention, the MMA contained in the above resin composition can improve the tack-free property by shortening the tack-free time and, if contained within a predetermined range, reduces the sprayability. Without this, the characteristics after formation can be made excellent. Therefore, as a monomer contained in the resin composition for gel coating, it has an excellent balance in properties.

Although the principle of improving the tack-free property by containing MMA is not clear, MMA has a boiling point of 1%.
It is around 00 ° C., and has a property that it is easily volatilized at the time of curing polymerization of the resin composition for gel coating. Because of this property,
The heating promotes the volatilization of MMA, and in the vicinity of the surface of the gel coat layer, drying occurs due to a layer containing a large amount of polymer (for example, "skinning"). Is considered to be

In the resin composition according to the present invention, when the above resin component (consisting of a polymer and a monomer) is 100% by weight, the component B in the resin component: MM
A is preferably contained in the range of 20% by weight or more and 60% by weight or less when the resin component is 100% by weight, and is contained in the range of 20% by weight or more and 50% by weight or less. Is more preferable.

When the content of MMA is less than 20% by weight, most of MMA is volatilized when the resin composition for gel coating is cured, and the effect of shortening the tack-free time by adding MMA cannot be obtained. Absent. On the other hand, if the content of MMA exceeds 60% by weight, the effect of shortening the tack-free time corresponding to the amount of MMA cannot be obtained, and in particular, the sprayability of the resin composition for gel coating is reduced. Not preferred.

Component C contained in the resin composition for gel coating according to the present invention: a high boiling monomer having a boiling point of 140
The compound is not particularly limited as long as it is a compound having a plurality of polymerizable double bonds in a molecule which is at least ° C and reacts with a monomer or a crosslinkable (meth) acrylic polymer contained in a resin component. Specifically, for example, styrene monomers such as styrene, vinyl toluene, α-methyl styrene, chlorostyrene, dichlorostyrene, t-butyl styrene, and vinyl toluene; n-butyl methacrylate;
iso-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate, hexyl methacrylate, octyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, glycidyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, bornyl methacrylate, Methacrylates such as iso-bornyl methacrylate; ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, propylene glycol di (meth) Acrylate, dipropylene glycol di (meth) acrylate, O neopentyl glycol di (meth)
Acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, trimethylolmethane tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa Polyfunctional (meth) acrylates such as (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,3-butanediol di (meth) acrylate; epoxy (meth) acrylates; divinylbenzene, diallyl phthalate, Diallyl isophthalate, triallyl cyanurate, triallyl isocyanurate; and the like.

In particular, the above-mentioned component C: high-boiling monomer includes:
When the component C is 100% by weight, the above polyfunctional (meth) acrylates, epoxy (meth) acrylates, or divinylbenzene, diallyl phthalate, diallyl isophthalate, triallyl cyanurate, triallyl isocyanurate, etc. More preferably, the polyfunctional monomer is contained in the range of 1% by weight or more and 50% by weight or less.

In the present invention, the spraying property of the resin composition is very important. The spraying property includes bubble bleeding property and film forming property. The addition can particularly improve the bubble elimination property.
Further, if the polyfunctional monomer is contained in a range of not more than half by weight in the total amount of the high boiling point monomer, the physical properties after the formation of the gel coat layer can be further improved.

Generally, the resin composition is applied by spraying while mixing with air. At this time, if air is not sufficiently removed from the resin composition formed in a layer, a pinhole is formed in the gel coat layer by the air. On the other hand, when a high-boiling monomer having a boiling point of 140 ° C. or higher is added to the resin composition, “skinning” generated by volatilization of MMA is suppressed to some extent, and the air bleeding time is secured for a certain period. As a result, the air is reliably released from the resin composition, and the formation of pinholes is suppressed.

To explain this point including the effect of “skinning” by MMA, MMA volatilizes to form “skinning” which becomes polymer-rich on the surface of the gel coat layer. If the composition is formed immediately after coating, the air is physically prevented from escaping. Therefore, the high-boiling point monomer having a boiling point of 140 ° C. or more is added in order to secure a certain amount of time required for “skinning” without heating.

That is, in the resin composition according to the present invention, even if the resin composition is applied to form a gel coat layer, the high-boiling monomer has a low volatility (compared to MMA). ", The occurrence of" skinning "by the MMA is suppressed, and the time for air bleeding can be sufficiently ensured. And "skinning" by MMA is caused by further volatilization at the time of heating, and the tack-free property is improved.

Therefore, in the resin composition for gel coating according to the present invention, in order to improve both tack-free property and air bleeding property, the content of component B: MMA and the content of component C: high boiling monomer Becomes important.

In the resin composition for gel coating according to the present invention, when the resin component is 100% by weight,
The content of the component C: high boiling monomer in the resin component is preferably in the range of 30% by weight or more and 70% by weight or less, more preferably 30% by weight or more and 60% by weight or less. preferable.

If the amount of the high boiling monomer in the resin component is less than 30% by weight, the content thereof is too small, and the volatilization of MMA is faster than that of all the air.
Are easily generated and the bubble-removing property decreases, which is not preferable. On the other hand, if it exceeds 70% by weight, the effect of improving the foam removal property corresponding to the added amount of the high boiling point monomer cannot be obtained, and the physical properties of the resin composition for gel coating may be deteriorated.

The resin composition for gel coating according to the present invention forms a gel coat by curing after being applied, and a curing agent (curing catalyst) is appropriately added for this curing.

The curing agent is not particularly restricted but includes diacyl peroxides, peroxyesters, hydroperoxides, dialkyl peroxides, ketone peroxides, peroxyketals, alkylperesters. Organic peroxide-based curing agents such as those based on organic peroxides and percarbonates can be used, but those having a 10-hour half-life temperature (t _1/10 ) of 80 ° C. or less are particularly preferred.

As the molding temperature (t _c ) at this time, a temperature (t _c = t _1/10 + 10 ° C.) higher than the 10-hour half-life temperature of the used curing agent by 10 ° C. or more is preferable. Thereby, the molding time can be shortened and the curability can be improved. The curing agent may be used in combination of two or more kinds, and the amount of the curing agent is preferably in the range of 0.5 part by weight or more and 5 parts by weight or less based on 100 parts by weight of the resin component.

When the resin composition for gel coating is cured, a curing accelerator, which will be described later, is usually used. When the curing accelerator is used, undesirable coloring of the gel coat layer and deterioration in physical properties after formation occur. On the other hand, if an organic peroxide having a 10-hour half-life temperature of 80 ° C. or less is used as a curing agent, the gel coat layer can be efficiently cured without using a curing accelerator substantially. . as a result,
The physical properties after formation are improved as compared with the case where a curing accelerator is used.

Therefore, when it is desired to improve the physical properties after formation without coloring the obtained gel coat, it is preferable not to use a curing accelerator. However, if the coloring or the physical properties after formation do not cause any problem, Since the use of a curing accelerator enables more efficient curing, a curing accelerator may be used for curing the gel coat.

When a gel coat is formed using the resin composition for gel coat according to the present invention, various additives may be added. Examples of the additive include, but are not particularly limited to, a curing accelerator, a thixotropic agent, an auxiliary thixotropic agent,
Antifoaming agents, pigments and the like can be mentioned.

The curing accelerator is not particularly limited, but specific examples thereof include cobalt naphthenate (cobalt naphthonate), cobalt octylate, and the like.
Divalent acetylacetone cobalt, trivalent acetylacetone cobalt, potassium hexoate, zirconium naphthenate (zirconium naphthonate), zirconium acetylacetonate, vanadium naphthenate (vanadium naphthonate), vanadium octylate (vanadium octonate), vanadium Acetylacetonate,
Metal soaps (higher organic acid metal salts) such as vanadium oxide acetylacetonate (vanadyl acetylacetonate) and lithium acetylacetonate; vanadium pentoxide;
Amines such as dimethylaniline and diethylaniline;
Phosphorus-containing compounds; β-diketones; and the like.

Two or more of the above-mentioned curing accelerators may be used in combination, and the addition amount thereof is preferably in the range of 0.001 to 5 parts by weight based on 100 parts by weight of the resin component. As described above, the curing accelerator is preferably not used for applications in which the gel coat layer is not colored and physical properties after formation are required. Also, it is better not to use it for applications requiring water resistance and weather resistance. When the curing accelerator is not substantially used, the above-mentioned organic peroxide having a 10-hour half-life of 80 ° C. or less may be used as the curing agent.

The thixotropic agent is not particularly limited as long as it gives the viscosity and thixotropic properties required for the resin composition for gel coating. Specific examples include silica powder and talc powder. , Mica powder, glass flakes,
Metal whiskers, ceramic whiskers, calcium sulfate whiskers, asbestos, smectite, organic thixotropic agents and the like can be mentioned.

Commercially available thixotropic agents include Leolosil QS series (manufactured by Tokuyama), Aerosil series (manufactured by Nippon Aerosil), BENATHIX series (manufactured by Wilbur Ellis), and FRANNKLIN FIBER (U
SG), talc SW, SS, SWE (manufactured by Nippon Talc), talcan powder PK, rotarku (manufactured by Hayashi Kasei), Albolex YS (manufactured by Shikoku Kasei Kogyo) and the like.

The amount of the thixotropic agent to be added depends on the shape of the object on which the gel coat is applied, in particular, the height, area and shape of the vertical surface, and the like.
Although it depends on the thickness of the gel coat to be applied, the ambient temperature, the properties of the resin composition or the resin (polymer) contained in the resin composition, it can be determined by the viscosity required for the resin composition.

For example, the viscosity of the resin composition was measured using a B-type viscometer at 25.degree. When measured under the conditions using 4, the thixotropic agent has a viscosity of
0.5 to 30 poise, preferably 1.0 to 25 poise,
More preferably, it is added in an amount such that the poise becomes 1.5 to 20 poise and the degree of change in rocking (ratio between 6 rpm and 60 rpm) becomes 2.0 to 10.0.

Depending on the properties of the resin composition for gel coating, the addition of the thixotropic aid can reduce the amount of the thixotropic agent added, and also allows the physical properties of the resin composition to be reduced. Can be improved.

Specific examples of the thixotropic auxiliary include glycols such as polyethylene glycol and polypropylene glycol; monofunctional or polyfunctional (meth) acrylates having a hydroxyl group and / or an ether bond; And / or epoxy ethers having an ether bond; epoxy esters having a hydroxyl group and / or an ether bond;
And the like are not particularly limited. In addition, various thixotropic agents, stabilizers, and the like can also be used as the thixotropic aid.

As commercial products of the thixotropic auxiliary, first, as the methacrylates, for example, trade name: Light Ester G-101P (glycerin dimethacrylate,
Kyoeisha Chemical), trade name: Light Ester G-201P
(2-hydroxy-3-acryloyloxypropyl methacrylate, manufactured by Kyoeisha Chemical), trade name: light ester MTG (methoxytriethylene glycol methacrylate, manufactured by Kyoeisha Chemical), trade name: light ester 3EG
(Triethylene glycol dimethacrylate, manufactured by Kyoeisha Chemical Co., Ltd.), trade name: Light Ester 4EG (polyethylene glycol # 200 dimethacrylate, average degree of polymerization 4,
Kyoeisha Chemical), trade name: Light Ester 9EG (polyethylene glycol # 400 dimethacrylate, average degree of polymerization 9, Kyoeisha Chemical), trade name: Light Ester 14
EG (polyethylene glycol # 600 dimethacrylate, average degree of polymerization 14, manufactured by Kyoeisha Chemical), trade name: Light Ester 130MA (methoxypolyethylene glycol methacrylate, manufactured by Kyoeisha Chemical), trade name: Light Ester 041MA (methoxy polyethylene glycol methacrylate, Kyoeisha Chemical) ), Trade name: Light Ester G-201P (2-hydroxy-3-acryloyloxypropyl methacrylate, manufactured by Kyoeisha Chemical Co., Ltd.).

The acrylates include, for example, trade name: light acrylate MTG-A (methoxy-triethylene glycol acrylate, manufactured by Kyoeisha Chemical), trade name: light acrylate 130A (methoxy-polyethylene glycol acrylate, manufactured by Kyoeisha Chemical) ), Trade name: Light Acrylate 3EG-4 (triethylene glycol diacrylate, manufactured by Kyoeisha Chemical), trade name: light acrylate 4EG-A (polyethylene glycol # 200 diacrylate, average degree of polymerization 4, manufactured by Kyoeisha Chemical), trade name : Light acrylate 9EG-A
(Polyethylene glycol # 400 diacrylate, average degree of polymerization 9, manufactured by Kyoeisha Chemical), trade name: Light Acrylate 14EG-A (polyethylene glycol # 600 diacrylate, average degree of polymerization 14, manufactured by Kyoeisha Chemical) and the like.

The epoxy ethers include:
For example, trade name: Epolite 100E (diethylene glycol diglycidyl ether, manufactured by Kyoeisha Chemical), trade name: Epolite 200E (polyethylene glycol # 2)
00 diglycidyl ether, average degree of polymerization 4, manufactured by Kyoeisha Chemical Co., Ltd., trade name: Epolite 400E (polyethylene glycol # 400 diglycidyl ether, average degree of polymerization 9,
Kyoeisha Chemical), trade name: Epolite 200P (tripropylene glycol diglycidyl ether, manufactured by Kyoeisha Chemical), trade name: Epolite 400P (polypropylene glycol # 400 diglycidyl ether, average polymerization degree 7, manufactured by Kyoeisha Chemical), trade name: Epolite 80MF (glycerin diglycidyl ether, manufactured by Kyoeisha Chemical Co., Ltd.) and the like.

Further, as the above-mentioned epoxy esters, trade names: epoxy ester 40EM (ethylene glycol diglycidyl ether / methacrylic acid adduct, manufactured by Kyoeisha Chemical), trade name: epoxy ester 70PA (propylene glycol diglycidyl ether / acrylic acid) Additive, manufactured by Kyoeisha Chemical), Trade name: Epoxy ester 2
00EA (polyethylene glycol # 200 diglycidyl ether / acrylic acid adduct, average degree of polymerization 4, manufactured by Kyoeisha Chemical) Trade name: Epoxy ester 400EA (polyethylene glycol # 400 diglycidyl ether / acrylic acid adduct, average degree of polymerization 9, 9, Kyoeisha) Chemical Products).

In addition, commercial products of the thixotropy-increasing and stabilizing agents are not particularly limited.
YK410, R605 (product number, manufactured by Big Chemie Japan) and the like.

Two or more of the above-mentioned thixotropic aids may be used in combination. The amount of addition depends on the properties of the gel coating resin composition and the type of the thixotropic aids, but is preferably 100 parts by weight of the resin component. Is in the range of 0.001 to 5 parts by weight, preferably 0.01 to 3 parts by weight.

The defoaming agent is not particularly limited either. For example, BYKA-515, A-5
55, A-501, A-500 (product number, manufactured by Big Chemie Japan), etc., a silicone-free foam-breaking polymer solution (non-silicone antifoaming agent);
An AP series, an OX series, an L series (trade name, manufactured by Kusumoto Kasei) and the like can be mentioned. The above-mentioned antifoaming agents may be used in combination of two or more. The amount of the defoaming agent is not particularly limited, but is preferably in the range of 0.01 to 3.0 parts by weight based on 100 parts by weight of the resin component.

The above-mentioned pigment is appropriately selected for the purpose of improving the decorative property, aesthetics, and weather resistance of the gel coat, and is not particularly limited. Commonly used for coloring purposes, such as white, red, condensed azo red, titanium yellow, cobalt blue quinacridone red, carbon black, iron black, ultramarine green, blue, perinone, navy blue, isoindolinone, chrome green, cyanine blue, and green Can be mentioned. Also, the amount of addition is not particularly limited.

In addition to the above, in particular, an ultraviolet absorber and / or an ultraviolet stabilizer may be added for the purpose of improving weather resistance. Specific examples of the ultraviolet absorber include benzophenone-based, benzotriazole-based, and cyanoacrylate-based compounds. Further, specific examples of the ultraviolet stabilizer include a hindered amine compound.

As the above-mentioned additives, reinforcing materials, fillers, modifiers, and / or flame retardants can be used. These additives are appropriately selected according to the purpose of use of the gel coat, and their types and specific compounds are not particularly limited.

As a specific method for forming a gel coat using the resin composition for gel coating according to the present invention, a conventionally known method can be used. In particular, in the present invention, the resin composition for gel coating is applied to a spray gun. Is very preferably used. However, the method of coating the resin composition is not limited to this, and various methods can be selected depending on the material, shape, surface state, and the like of the object to be coated.

As the above-mentioned spray gun, a pressure-feeding type, a gravity type, and a suction type can be suitably used as a gel coat supply type, but it is not particularly limited.
The spraying conditions (coating conditions) using a spray gun are not particularly limited. For example, the gun diameter is in the range of 0.5 mm to 3.0 mm, and the blowing air pressure is 1.0 kg / cm. ^{2 to} 7.0 kg
/ Cm ² , air consumption is 70 liters / min ~
The range of 600 liters / minute and the amount of gel coat jetting are preferably in the range of 80 ml / minute to 700 ml / minute.

The above-mentioned spraying conditions are determined by the properties (viscosity, degree of change in shaking, bubble removal) of each resin composition for gel coating,
The shape of the object on which the gel coat is applied, especially the height of the vertical surface,
Each condition is set (adjusted) according to the area and shape, the applied thickness of the applied gel coat, the ambient temperature, and the like. By adjusting the composition, the resin composition for gel coating according to the present invention can exhibit extremely excellent spray properties even under these conditions.

In addition to the above-mentioned spray gun, other methods of forming the gel coat include (1) application by brush (for example, application using a brush to apply paint, etc.) depending on the application and the shape of the object. (2) coating with a bar coater (flowing the resin composition to a portion where a certain gap is provided, and applying the resin composition to an object using a bar (stick) so as to have a constant coating thickness). And the like.

The resin composition for gel coating according to the present invention has improved sprayability due to its excellent bubble-removing property and film-forming property.
Since bubble removal properties and film forming properties are important, the resin composition according to the present invention can be suitably applied (painted) even by the above-mentioned method (1) or (2). In view of productivity and versatility, a method using the above-mentioned spray gun is preferable.

In the present invention, when forming the gel coat layer,
In addition to improving the forming properties including the spraying properties including film forming properties and bubble removal properties and the tack-free properties, the physical properties of the resulting gel coat layer after formation are also improved. However, since the physical properties after formation of the gel coat layer include a plurality of physical properties such as abrasion resistance and various durability properties, it is not necessary to improve all of these physical properties in actual use.

That is, in the resin composition for gel coating according to the present invention, it is sufficient that the necessary physical properties among a plurality of physical properties after formation are selectively improved according to the use of the gel coat layer. The content of the component B: methyl methacrylate contained in the resin composition and the content of the component C:
The type and content of the high-boiling monomer are appropriately selected and set according to the purpose of use of the gel coat layer.

As the method for evaluating the forming characteristics in the present invention, it is sufficient to evaluate at least the film-forming property and the bubble removal property for the spray property, and the tack-free time for the tack-free property. In addition, as a method for evaluating physical properties after formation in the present invention, necessary physical properties may be appropriately evaluated depending on the purpose of use of the gel coat as described above. Examples of such physical properties include, for example, evaluation of scratch resistance (the surface hardness of the gel coat is indicated by pencil hardness),
Evaluations such as heat resistance, water resistance, solvent resistance, and weather resistance as durability characteristics are given.

In the method for producing a molded article according to the present invention, the above-mentioned resin composition for gel coating is applied to a mold and cured until tack-free, and then a back layer is formed on the gel coat layer. That is, in the present invention, a gel coat layer forming step of first forming a gel coat layer is performed,
Next, after performing a gel coat layer curing step of curing the formed gel coat layer to tack-free, a lamination step of laminating a back layer is further performed in this order.

As described above, when laminating the back layer on the gel coat layer, the gel coat layer must be tack-free. Therefore, in the method for manufacturing a molded article according to the present invention, the gel coating layer curing step is performed first, and then the lamination step is performed.

In the present invention, since the resin composition for gel coating having excellent tack-free properties is used, the tack-free time in the gel coat layer curing step can be shortened. Further, since the resin composition for gel coating is excellent in sprayability, a high quality gel coating layer can be efficiently formed by coating the gel coating layer by a spray method. Therefore, the time from the gel coat forming step to the laminating step can be shortened, and a molded article having a high quality gel coat layer can be manufactured very efficiently.

The above-mentioned back layer refers to a gel coat formed body (formed body) on which a gel coat layer is formed, and usually a fiber reinforced plastic (FRP) layer or an artificial marble layer is very preferable. No. F
As the RP, for example, a known matrix resin layer such as an unsaturated polyester resin, a vinyl ester resin, an epoxy resin, a urethane resin, a phenol resin, a roving, a chopped strand mat, a roving cloth,
A glass fiber reinforced plastic reinforced with glass fiber having a conventionally known shape such as a glass cloth and a chipped strand may be mentioned, but is not particularly limited.

The artificial marble is not particularly limited, but may be, for example, an unsaturated polyester resin, a vinyl ester resin, a (meth) acrylic resin (syrup)
Etc. are used, if necessary, fillers such as aluminum hydroxide, glass filler, calcium carbonate, silica powder, coupling agents, internal release agents, fiber reinforcing materials, pigments,
Examples of the resin composition include known additives such as a defoaming agent and a curing agent. Above all, by using (meth) acrylic resin (syrup), artificial marble excellent in various physical properties can be obtained.

The artificial marble layer is generally made of FR.
Since the strength is lower than that of the P layer, if only the artificial marble layer is used as the back layer in an application such as a bathtub, there may be a practical problem due to insufficient strength of the artificial marble layer. Therefore, for example, after forming an artificial marble layer as a back layer, an FRP layer may be laminated for the purpose of further reinforcing the strength of the back layer. That is, the molded article with gel coat obtained in the present invention may be composed of three layers of gel coat, artificial marble and FRP.
Further, depending on the use of the molded article, various layers more than this may be laminated.

As described above, the resin composition for gel coating according to the present invention comprises at least a component A: a (meth) acrylic polymer, a component B: methyl methacrylate, and a component C: a high boiling point monomer having a boiling point of 140 ° C. or higher. It contains a resin component composed of a monomer as a main component.

[0152] Therefore, since the film-forming property and the bubble-removing property are improved, the forming characteristics when spray is adopted as the coating method are further improved. In addition, various properties of the obtained gel coat layer can be sufficiently improved. Therefore, by using the resin composition for gel coating, a high quality gel coat having sufficient surface hardness and high surface protection function can be obtained.

Further, since the resin composition for gel coating according to the present invention is also excellent in tack-free property, the tack-free time can be shortened in producing a molded article having a gel coat layer. Therefore, in the method for producing a molded article according to the present invention, the gel coat layer is cured to tack-free first and then the back layer is laminated, whereby a molded article with a gel coat can be produced very efficiently. .

The (meth) acrylic polymer includes a non-crosslinkable or crosslinkable (meth) acrylic polymer and a non-crosslinkable or crosslinkable (meth) acrylic syrup. Among these, (meth) acrylic syrup obtained by partial polymerization of bulk polymerization is preferable, and crosslinkable (meth) acrylic syrup is more preferable, but is not particularly limited.

[0155]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Synthesis Examples, Examples, Comparative Examples, and Conventional Examples, but the present invention is not limited thereto. In the following description, parts by weight are simply abbreviated as “parts”, and weight% is also simply abbreviated as “%”.

In addition, the bubble-releasing property, film-forming property, tack-free time (forming property) of the gel coating resin composition, the surface hardness of the formed gel coat (scratch resistance property), heat resistance, water resistance, and water resistance , Weather resistance and solvent resistance (durability) were measured or evaluated by the following methods.

[Bubble Removability] The resin composition for gel coating was
After 15 minutes of application on a bathtub mold made of RP, the state of the surface was visually checked. At this time, the case where no bubble was visually observed and there was substantially no problem was evaluated as ○, the case where several bubbles could be visually confirmed, and the case where countless bubbles could be visually confirmed as ×.

[Film Forming Property] The resin composition for gel coating was prepared using FR
After being applied (painted) on a bathtub mold made of P, it became tack-free at a predetermined temperature, and the state of the surface was visually checked. At this time, if the surface is smooth and there is no problem, ○, slight cracks and irregularities occur on the surface and the smoothness is not good, but if it reaches a practical level to some extent, Δ, cracks and irregularities are too large, In the case where the level did not reach the practical level due to the occurrence of a wide range and the smoothness was too poor, the evaluation was evaluated as x.

[Tack-free time] 3 hours at a predetermined curing temperature
Every 0 minutes, it was confirmed whether or not the gel coat layer was sticky by hand (by tactile inspection), and the time when the gel coat layer was free of stickiness was measured.

[Heat Resistance] The molded article on which the gel coat layer was formed was left in an oven set at 100 ° C. for 5 hours, and the appearance of the gel coat layer was visually checked. At this time, the case where there was no change compared to before standing was evaluated as ○, and at least one of slight discoloration and a change in gloss was confirmed. At least one of the changes was confirmed, and when it did not reach the practical level, it was evaluated as x.

[Water Resistance] The molded article on which the gel coat layer was formed was left in water at 80 ° C. for 500 hours, and the appearance of the gel coat layer was visually checked. At this time, the case where there was no change compared to before standing was evaluated as ○, and at least one of slight discoloration and a change in gloss was confirmed. At least one of the changes was confirmed, and when it did not reach the practical level, it was evaluated as x.

[Weather Resistance] The molded article on which the gel coat layer was formed was subjected to a 300-hour weather resistance test using a sunshine weather meter based on JIS A1415, and the appearance of the gel coat layer was visually observed. confirmed. At this time, the case where there was no change compared to before the test was evaluated as ○, and at least one of slight discoloration and a change in gloss was confirmed. At least one of the changes was confirmed, and when it did not reach the practical level, it was evaluated as x.

[Solvent resistance] The molded article on which the gel coat layer was formed was immersed in acetone for 1 hour, and the appearance of the gel coat layer was visually checked. At this time, when there was no change compared to before leaving, ○, a slight change in gloss was confirmed, but when it reached a practical level to some extent, Δ, a large change in gloss was confirmed, reaching a practical level. The case where it was not performed was evaluated as x.

[Surface Hardness] The molded article on which the gel coat layer was formed was subjected to a hardness test based on JIS A1415, and the pencil hardness at which a flaw was clearly formed under a load of 1000 g was measured.

Next, examples of the gel coat resin composition according to the present invention and a gel coat formed using the resin composition will be described.

Synthesis Example 1 To a reaction vessel equipped with a thermometer, a cooling pipe, a gas introduction pipe, a dropping funnel, and a stirrer, 3000 g of toluene was charged, and the inside of the reaction vessel was replaced with nitrogen gas. Next, the temperature was raised to 80 ° C. while stirring, and AIBN
A mixture of 1 part of (azobisisobutyronitrile), 193 parts of methyl methacrylate (methyl methacrylate, MMA), 7 parts of methacrylic acid (MAA), and 1.5 parts of β-mercaptopropionic acid was taken for about 4 hours. 8
The polymerization was carried out while maintaining the temperature at 0 ° C.

After completion of the dropwise addition, 0.5 parts of AIBN was added, and the mixture was further reacted for 3 hours. Next, at the same time as blowing air into the system, 0.05 parts of hydroquinone was added to terminate the radical polymerization. Then glycidyl methacrylate 12
After adding 0.4 part of tetraphenylphosphonium bromide, the temperature was raised to 100 ° C., and the mixture was reacted in an air atmosphere for 5 hours. After that, toluene was removed to some extent by heating under reduced pressure, and the polymerization completed product was dropped into a large amount of methanol little by little.

The crosslinked polymer precipitated in methanol was further washed several times with methanol. The obtained crosslinkable polymer was dried at 60 ° C. for 120 minutes to obtain a crosslinkable (meth) acrylic polymer as Component A used in the present invention. G
The molecular weight of the (meth) acrylic polymer measured using a PC was a number average molecular weight Mn = 3.5 × 10 ⁴ and a weight average molecular weight Mw = 6.2 × 10 ⁴ . The molecular weight per polymerizable double bond was 2.3 × 10 ³ .

Example 1 Component A obtained in Synthesis Example 1
20 parts of a crosslinkable (meth) acrylic polymer (hereinafter, abbreviated as a crosslinkable polymer) were added to Component B: 50 parts of MMA and Component C:
It was dissolved in 30 parts of a styrene monomer (St). next,
3 parts of thixotropic agent (silica powder, manufactured by Nippon Aerosil, trade name: Aerosil #
200), 1 part of shaking change assistant (polyethylene glycol #)
400 dimethacrylate, manufactured by Kyoeisha Chemical, trade name: Light Ester 9EG), 0.3 parts of defoamer (non-silicone defoamer, manufactured by BYK Chemie, trade number: BYK A-51)
5), 2 parts of a curing agent (manufactured by Kayaku Akzo, trade name: Kayaester CND, α-cumylperoxyneodecanate) were added and stirred well to obtain a clear gel coat resin composition according to the present invention. .

The above resin composition for clear gel coating was applied to a gravity spray gun (spray conditions: 2.5 mm in diameter, 4 kg / cm ^{2 of} spraying air pressure, 300 liter / min of air consumption, 400 ml / min of jetting gel coat). And FR
The gel coat was applied (painted) to the bathtub mold for P in a state where a space of 20 cm was provided so that the applied thickness of the gel coat was 0.5 mm. Then, the coating was left at room temperature for 15 minutes to evaluate the foam removal property of the coated product. Then, the tack-free time was evaluated by heating the FRP bathtub mold coated with the resin composition in a curing oven at 60 ° C. At this time, it was tack-free in 30 minutes. Further, the film forming property of the gel coat was evaluated.

5 parts of titanium white was added to 100 parts of the clear gel coat resin composition to prepare a white gel coat resin composition. This was applied to the previously cured gel coat layer by spraying in the same manner as the clear gel coat resin composition, and was cured. Next, an unsaturated polyester resin (Nippon Shokubai Co., Ltd.)
Manufactured and trade name: EPORAC N-350TIB) and a glass fiber reinforced plastic layer is formed and cured using glass fiber, demolded, and a glass fiber reinforced plastic molded article having a gel coat layer (hereinafter abbreviated as FRP gel coat molded article). I got

Using the above FRP gel coat molded product, various physical properties of the gel coat layer were evaluated or measured. The results are shown in Table 1 together with the results of the spray properties (above-mentioned bubble-removing properties and film-forming properties) and tack-free properties.

[Embodiments 2 and 3] In Embodiment 1,
Component A: crosslinkable polymer, component B: MMA, and component C: styrene monomer (St) were mixed and stirred at the contents shown in Table 1 in the same manner as in Example 1 except that the resin composition for clear gel coating was used. , And an FRP gel coat molded product were obtained, and the formation characteristics and various physical properties (various characteristics) of the gel coat layer were evaluated. Table 1 shows the results.

[Examples 4 to 18] In Example 1, the content of the component A: crosslinkable polymer and the component B: MMA were as shown in Table 1, and the component C was replaced with a styrene monomer (St). n-butyl acrylate (B
A) and / or t-butyl methacrylate (t-BM
A) is used at the content in Table 1 (Examples 4 to 8), cyclohexyl methacrylate (CHMA) and / or ethylene glycol dimethacrylate (EGDMA),
Alternatively, except that trimethylolpropane trimethacrylate (TMPTMA) is used at the content shown in Table 1 or Table 2 (Examples 9 to 17), or EGDMA is used at the content shown in Table 2 in addition to St (Example 18). Example 1
And a resin composition for clear gel coating, and F
RP gel coat molded articles were obtained and various properties were evaluated. Table 1 shows the results.

[Conventional Examples 1 and 2] A conventional resin composition for gel coating and a glass fiber reinforced plastic molded article having a gel coat layer were prepared by the method disclosed in Examples in JP-A-3-66719. Got the kind.

That is, as the component A: the polymer of the above-mentioned Synthesis Example 1 was used as the crosslinkable (meth) acrylic polymer, and the component C was obtained by using St as an aromatic vinyl monomer without using the component B. Conventional resin components were obtained using the contents shown in Table 2. Except for this, in the same manner as in Example 1, a conventional resin composition for gel coating and a conventional FRP gel coat molded product were obtained and various properties were evaluated. Table 2 shows the results.

[Comparative Examples 1 to 5]
As shown in Table 2, whether Component C was used (Comparative Example 1
2) Alternatively, a resin composition for comparative gel coat and a comparative FRP gel coat molded product were obtained in the same manner as in Example 1 except that component B was not used (Comparative Examples 3 to 5), and various properties were evaluated. Table 2 shows the results.

[0178]

[Table 1]

[0179]

[Table 2]

In Tables 1 and 2, examples are indicated by numbers only, comparative examples are indicated by "ratio", and conventional examples are indicated by "sub".

As is apparent from Examples 1 to 18, the resin composition for clear gel coating according to the present invention is very excellent in sprayability and has a tack-free time of about 60 minutes. It also has excellent properties. Further, the obtained gel coat layer also exhibits extremely excellent post-formation physical properties.

On the other hand, in the conventional examples 1 and 2 containing no component B: MMA, the forming properties such as sprayability and tack-free time of the conventional example 1 having a high styrene monomer content are not much different from those of the present invention. After the formation of the gel coat layer, the physical properties are low. Further, in Conventional Example 2 in which the content of the styrene monomer is low, the film-forming property is extremely poor and a gel coat layer cannot be formed at all.

Further, as is apparent from Comparative Examples 1 and 2,
Component C: When no high-boiling-point monomer is contained, the bubble removal property is extremely deteriorated. As is clear from Comparative Example 3,
Component B: When MMA was not included and only styrene monomer was included as Component C, the physical properties after the formation of the gel coat layer were low as in Conventional Example 1, and it was clear from the comparison with Example 2. Like, tack free time is 3
The length is longer from 0 minutes to 60 minutes, and it can be seen that the tack-free property is reduced by not including the component B.

Similarly, as is apparent from Comparative Examples 4 and 5, when the component B: MMA was not contained and the styrene monomer was not used as the component C, the tack-free time reached 90 minutes, and the component B: MMA It can be seen that the tack-free property is significantly reduced when no is contained.

[Synthesis Example 2] MMA193 was added to a reaction vessel equipped with a thermometer, a cooling pipe, a gas introduction pipe, and a stirrer.
Parts, 7 parts of MAA and 1.5 parts of β-mercaptopropionic acid, and the inside of the reaction vessel was purged with nitrogen gas. Next, these were heated to 80 ° C. with stirring, 0.05 parts of AIBN was added, and polymerization was carried out for 3 hours while maintaining at 80 ° C.

Then, at the same time as air was blown into the reaction vessel, 0.05 parts of hydroquinone was added to terminate the radical polymerization. Then, glycidyl methacrylate 12
After adding 0.4 parts of tetraphenylphosphonium bromide, the mixture was heated to 100 ° C. and reacted in an air atmosphere for 5 hours to obtain a crosslinkable (meth) acryl syrup as the component A used in the present invention. Was.

The solid content of the crosslinkable (meth) acrylic syrup (ie, the amount of the (meth) acrylic polymer) was 5%.
0.1%. The molecular weights measured using GPC were Mn = 3.0 × 10 ⁴ and Mw = 6.0 × 10 ⁴ .
Furthermore, the molecular weight per polymerizable double bond is 2.3 × 10
^{Was 3} .

[Examples 19 to 25] In the above Example 1, Component A was replaced with Synthetic Example 2 in place of the crosslinkable polymer.
Resin composition for gel coating in the same manner as in Example 1 except that the crosslinkable (meth) acrylic syrup (hereinafter abbreviated as crosslinkable syrup) obtained in the above was used, and the contents of components A to C were changed as shown in Table 3. And FRP gel coat molded articles were obtained and various properties were evaluated. Table 3 shows the results.

In Examples 19 to 25, the crosslinkable syrup as the component A contains about half of the component B: MMA. Table 3 shows the amount of MMA added at the time of preparation. And the total amount of component B: MMA, including the amount of MMA contained in the crosslinkable syrup, is described in the “total amount” of the lower row.

Example 26 A resin composition for clear gel coating was obtained in the same manner as in Examples 19 to 25 except that the contents of components A to C were as shown in Table 3. Thereafter, as described in Example 1 above, a gel coat layer was applied to a bathtub type for artificial marble with a gravity type spray gun, and the foam removal property, tack-free property, and film forming property were evaluated. Table 3 shows the results.

Next, a crosslinkable (meth) acryl syrup 70
And 30 parts of MMA were mixed to obtain a crosslinkable (meth) acrylic syrup for (meth) acrylic artificial marble. Silica powder (manufactured by Hepworth Minerals and Chemicals Limited, trade name: Cristobalite X) was used as a filler for 100 parts of the (meth) acrylic syrup.
PF6SM) 150 parts, stearic acid 0.4 part as an internal mold release agent, silane coupling agent (manufactured by Nippon Unicar, product number: A-174) 1.5 as a coupling agent
Part, antifoaming agent (manufactured by Big Chemie Japan, product number: A-
515) 0.2 part, 1.0 part of bis (4-t-butylcyclohexyl) peroxydicarbonate (manufactured by Kayaku Akzo, trade name: Parkadox 16) as a curing agent, and 1,1,3, 3-tetramethylbutylperoxy 2-
Ethyl hexanate (manufactured by Kayaku Akzo, Kayaester TM
PO-70) was added to obtain a (meth) acrylic artificial marble resin composition.

This (meth) acrylic artificial marble resin molded product was cast into a bathtub having the above-mentioned gel coat layer coated thereon by a conventionally known method. Thereafter, the artificial marble layer was cured by heating in a curing furnace at 70 ° C. for 60 minutes. next,
In the same manner as in Example 1, a glass fiber reinforced plastic (FRP) layer is formed on the artificial marble layer by a conventionally known method, cured, demolded, and has a gel coat layer (meta).
An acrylic artificial marble bathtub (abbreviated as a human-sized gel coat molded product) was obtained. The physical properties of the gel coat layer were evaluated or measured using this molded gel coat product. Table 3 shows the results.

[0193]

[Table 3]

[Synthesis Example 3] In the same reaction vessel as in Synthesis Example 2, 193 parts of MMA, 7 parts of MAA and 1.5 parts of β-mercaptopropionic acid were charged, and the inside of the reaction vessel was replaced with nitrogen gas. Next, these were heated to 80 ° C. while stirring, and A
0.05 parts of IBN was added and polymerized for 3 hours. At the same time as blowing air into the reaction vessel, 0.05 parts of hydroquinone was added to terminate the radical polymerization to obtain a non-crosslinkable (meth) acrylic syrup as Component A used in the present invention.

The solid content of the non-crosslinkable (meth) acrylic syrup (ie, the amount of the (meth) acrylic polymer) was 5%.
0.5%. The molecular weights measured using GPC were Mn = 3.0 × 10 ⁴ and Mw = 6.0 × 10 ⁴ .

[Examples 27 to 32] In Example 1, the procedure of Synthesis Example 3 was repeated, except that the component A was replaced with a crosslinkable polymer.
Gel-coating resin in the same manner as in Example 1 except that the non-crosslinkable (meth) acrylic syrup (hereinafter, abbreviated as non-crosslinkable syrup) obtained in the above was used and the contents of components A to C were as shown in Table 3. The composition and the FRP gel coat molded product were obtained and various properties were evaluated. Table 4 shows the results.

In Examples 27 to 32, since the non-crosslinkable syrup as the component A contains about half of the component B: MMA, Table 4 shows the amount of the MMA added at the time of preparation. The amount is shown at the top, and the total amount of component B: MMA including the amount of MMA contained in the crosslinkable syrup is shown at the bottom.

[0198]

[Table 4]

As is clear from Examples 19 to 32, even when a crosslinked syrup or a non-crosslinked syrup is used as the component A, the component B: the final content of MMA is within a predetermined range. If spray, tack-free,
It can be seen that all the physical properties of the gel coat layer are excellent. Further, as is clear from the comparison between Example 24 and Example 26, if the resin composition according to the present invention had an artificial marble even though the obtained molded article had FRP as the back layer. However, it is possible to obtain a molded article having a gel coat layer having extremely excellent characteristics.

Embodiments 33 to 40 Embodiments 1 and 1
In 0, 11, or 15, whether 2 parts of Kayamec L (trade name, ketone peroxide type, manufactured by Kayaku Akzo) and 0.03 part of cobalt octylate (cobalt octenoate) are used as curing accelerators ( Examples 33 to 3
6) or Trigonox 23-C70 (trade name,
t-butyl peroxy neodecaneate, manufactured by Kayaku Akzo)
Was used in the same manner as in Examples 1, 10, 11, and 15, except that 2 parts of the resin composition were used (Examples 37 to 40), and a resin composition for a clear gel coat and an FRP gel coat molded product were obtained and various properties were evaluated. . Table 5 shows the results.

[Conventional Example 3] In Conventional Example 1, Kayamec L (trade name, manufactured by Kayaku Akzo) was used as a curing accelerator.
Was used, and a conventional resin composition for gel coating, and a conventional FRP gel coat molded product were obtained in the same manner as in Conventional Example 1 except that 2 parts of octylate and 0.03 part of cobalt octylate were used, and various properties were evaluated. Table 5 shows the results.

[0202]

[Table 5]

[Embodiments 41 to 48] The foregoing Embodiments 1 and 1
At 0, 11 or 15, using 2 parts of Kayaester TMPO-70 (trade name, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanate, manufactured by Kayaku Akzo) as a curing agent A curing temperature of 75 ° C. (Examples 41 to 44) or a curing temperature of 85 ° C. using Kayaester O (trade name, t-butylperoxy 2-ethylhexanate, manufactured by Kayaku Akzo) in two parts (Examples 45 to 48), except that
In the same manner as in 10, 11, and 15, a resin composition for clear gel coating and an FRP gel coat molded product were obtained, and various properties were evaluated. Table 6 shows the results.

[0204]

[Table 6]

As is apparent from the above Examples 33 to 48, the resin composition according to the present invention can be compared with Conventional Example 3 even if the curing agent is changed, even if the curing agent is changed. It turns out that all the various physical properties become excellent.

[0206]

As described above, in the resin composition for gel coating according to the present invention, assuming that the resin component is 100% by weight, component A: (meth) as a polymer in the resin component
The acrylic polymer is contained in a range of 5% by weight or more and 30% by weight or less, and as a monomer, Component B: methyl methacrylate is contained in a range of 20% by weight or more and 60% by weight or less, and Component C is used. : High boiling monomer having a boiling point of 140 ° C. or higher is contained in a range of 30% by weight or more and 70% by weight or less.

According to the above constitution, high sprayability can be obtained with the component C, high tack-free property can be obtained with the component B, and various physical properties can be obtained in the gel coat layer formed with the component A. It does not hinder each property. Therefore, there is an effect that both the formation characteristics and the physical properties after the formation of the gel coat layer can be greatly improved.

Further, in the method for producing a molded article according to the present invention, a gel coat layer forming step of applying the resin composition for gel coating to a mold, and a gel coat layer curing step of curing the applied gel coat layer to tack-free. ,
After the gel coat layer curing step, a laminating step of forming a back layer on the gel coat layer is included. Therefore, it is possible to shorten the time required for performing the laminating step after the gel coat forming step as compared with the related art, and it is possible to improve the manufacturing efficiency of the molded article having the gel coat layer.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // B29L 9:00 B29L 9:00 F term (reference) 4F204 AA41 AD11 AD16 AG03 AH44 AH49 FA01 FB01 FB22 4J011 PA69 PC02 4J027 AA01 AA02 BA07 CB04 CC02 CD08 4J038 CG141 CG142 CH031 CH032 CH041 CH042 CH071 CH072 CH171 CH172 CH201 CH202 DB221 DB222 FA041 FA042 FA111 FA112 FA121 FA122 FA151 FA152 FA201 FA202 GA06 JA66 KA03 NA04 NA14 NA04 NA07

Claims (5)

[Claims] 1. A gel coat which is formed as an outer layer on the surface of a molded article and contains a resin component composed of a polymer and a monomer as a main component. In the resin component, as a polymer, component A: a (meth) acrylic polymer is contained in a range of 5% by weight or more and 30% by weight or less, and as a monomer, component B: methyl methacrylate is used. For gel coating, characterized in that the content thereof is in the range of 20% by weight or more and 60% by weight or less, and component C: a high boiling point monomer having a boiling point of 140 ° C. or more in a range of 30% by weight or more and 70% by weight or less. Resin composition. 2. The above-mentioned component C:
The resin composition for gel coating according to claim 1, wherein the polyfunctional monomer is further contained within a range of 1% by weight or more and 50% by weight or less, when 100% by weight. 3. The gel coating resin composition according to claim 1, wherein said component A: (meth) acrylic polymer has a polymerizable double bond in the molecule. 4. The resin composition for gel coating according to claim 1, further comprising an organic peroxide having a 10-hour half-life of 80 ° C. or less as a curing agent. 5. A gel coat layer forming step of applying the gel coat resin composition according to any one of claims 1 to 4 to a mold, and a gel coat layer hardening the applied gel coat layer until tack free. And a laminating step of forming a back layer on the gel coat layer after the gel coat layer curing step.