JP2001261750A - (meth)acrylic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a (meth)acrylic resin composition capable of providing high production efficiency by promptly being cured even with heating at a middle temperature, scarcely causing coloring to the obtained cured product of the resin and capable of imparting excellent physical properties thereto. SOLUTION: This (meth)acrylic resin composition comprises a combination of an organic peroxidic primary curing agent and a curing accelerator having redox reactivity with the primary curing agent ad a secondary curing agent having no redox reactivity with the curing accelerator and having <=60 deg.C 10 h half-life temperature. Thereby, since the (meth)acrylic resin composition can promptly be cured and the amount of the curing accelerator can be reduced, the coloring of the obtained cured product of the resin is hardly observed and the cured product of the resin excellent in good appearance and decoration properties can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a (meth) acrylic resin composition, and more particularly to a (meth) acrylic resin composition which is cured using a curing agent and a curing accelerator.

[0002]

2. Description of the Related Art A (meth) acrylic resin composition is used for various purposes. A (meth) acrylic polymer and a (meth) acrylic monomer are prepared by, for example, mixing a (meth) acrylic syrup (liquid Resin). Conventionally, the curing method of this (meth) acrylic resin composition (hereinafter, may be simply referred to as a resin composition) includes three methods of room temperature curing, medium temperature heating curing, and high temperature heating curing depending on a molding temperature. They can be roughly classified.

At room temperature curing, the above resin composition is cured at room temperature (or room temperature, usually -10 ° C.) using a curing agent (organic peroxide).
This is a system that cures without heating within the range of about 35 ° C., and usually uses a curing accelerator together. For the purpose of improving various physical properties, a method of further curing the cured product by post-curing (after-curing) as necessary is often used.

[0004] Medium-temperature heat curing uses a curing agent (organic peroxide).
At a medium temperature (a temperature range higher than room temperature and lower than the high temperature described later, here, 35 ° C. to 80 ° C.).
(Within the range of the degree), and there are two methods, a method of decomposing a curing agent (organic peroxide) only by heat and a method of using a curing accelerator together. . This medium temperature heat curing usually has a higher curing rate than normal temperature curing and has high productivity. In addition, also in this middle-temperature heat curing, post-curing may be performed as needed, similarly to room temperature curing.

[0005] High-temperature heat curing is performed by using a curing agent (organic peroxide).
Is a system in which the above resin composition is cured by decomposing a curing agent (organic peroxide) only with heat, usually at a high temperature (usually a temperature exceeding 80 ° C.), and the curing speed is the thermal decomposition of the curing agent. Depends on speed.

[0006] In the above-mentioned high-temperature heat curing, a resin cured product having a sufficient surface hardness, that is, a resin that has sufficiently cured, can be cured more quickly in response to heating than a room-temperature curing or a medium-temperature heating curing. A cured product can be obtained, and post-curing is rarely performed. Therefore, the above 3
The highest productivity among the two curing methods.

However, in this high-temperature heat curing, high energy is required to realize high-temperature heating, so that the energy cost is increased and the molding die used for the curing has high-precision durability having high temperature durability. Since a product is required, the cost of the mold also increases. As a result, there is a problem that the economic efficiency is extremely low as compared with the ordinary temperature curing and the intermediate temperature curing.

Therefore, in view of the characteristics and problems of the above three curing methods, if the curing speed is increased (that is, if the productivity is improved) in the medium temperature curing, the curing method of the (meth) acrylic resin composition is improved. Can be particularly preferable.

On the other hand, the (meth) acrylic monomer has a strong anaerobic property, and therefore has a property that the curing is inhibited on the air contact surface.
When a thin film of about m is cured under air contact, there is a problem that a sufficient curing speed cannot be obtained. Specifically, in room temperature curing or middle temperature heating curing, the curing time of the resin composition is preferably within 30 minutes, and if it exceeds 30 minutes, the productivity is greatly reduced. Therefore, as described above, a method of rapidly promoting curing by using a curing agent in combination with a curing accelerator is often applied.

Examples of the combination of the curing agent and the curing accelerator include ketone peroxide (eg, methyl ethyl ketone peroxide (MEKPO))-organic acid metal salt (eg, cobalt salt); hydroperoxide-organic acid metal salt or Metal oxides; benzoyl peroxide-tertiary amines (such as dimethylaniline);
And the like. JP-A-63-51410 discloses a technique in which an alkyl acetoacetate peroxide-cobalt organic acid salt is used as a combination of a curing agent and a curing accelerator.

By the combination of the curing agent and the curing accelerator, a redox reaction occurs when the resin composition is cured. Therefore, it is possible to accelerate the curing even under a high temperature condition, and it is possible to improve the curing speed as compared with the case of using the curing agent alone.

[0012]

However, in the curing of a resin composition by the above-mentioned combination of a curing agent and a curing accelerator, the use of a large amount of a cobalt salt or an amine as a curing accelerator involves the following steps. 1. The obtained cured resin is colored, and This causes a problem that the physical properties of the obtained cured product are reduced.

[0013] The cured (meth) acrylic resin is used for applications requiring aesthetics and decorativeness, such as, for example, an artificial marble molded product. In such applications, medium temperature heat curing is generally selected. Here, artificial marble moldings include
Since not only improvement in various physical properties but also aesthetic appearance and decorativeness are required, coloring of the resin cured product with a large amount of cobalt salt (problem 1 above) should be avoided.

Therefore, a method of avoiding coloring by reducing the amount of a curing accelerator such as a cobalt salt and curing the resin composition can be considered. Certainly, by using this technique, the coloring of the cured resin can be substantially avoided, but instead, the curing speed is lowered and various physical properties such as surface hardness are also insufficient (problem 2 above). Invite.

[0015] Further, a method is considered in which curing is performed using only a curing agent for "medium-temperature heating" that can realize a sufficient curing speed without causing a redox reaction without using a combination of a curing agent and a curing accelerator that causes a redox reaction. Can be In this method, no coloring is observed in the cured resin because no curing accelerator is used, and a sufficient curing speed can be obtained because a curing agent for “medium temperature heating” is used. Problems that various physical properties are deteriorated (problem 2 above)
Invite. That is, in order to obtain sufficient physical properties in the medium-temperature heat curing, it is necessary to use a combination of a curing agent and a curing accelerator that causes a redox reaction.

Therefore, in order to realize good curing, a combination of a curing agent and a curing accelerator which causes a redox reaction while reducing the amount of a cobalt salt is used, and "high-temperature heating" curing which does not cause a redox reaction. A technique using a combination of agents is also conceivable. However, in this method, the curing speed is low and various physical properties are insufficient, and only the same result as when the amount of the cobalt salt is simply reduced is obtained.

As described above, in the conventional medium-temperature heat curing, when a curing method using a combination of a curing agent and a curing accelerator that causes a redox reaction is used, the obtained resin cured product may be colored or various physical properties may be reduced. Therefore, there has been a problem that its use is limited.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to obtain a high production efficiency by rapidly curing even by heating at a medium temperature, and to obtain a cured resin product. An object of the present invention is to provide a (meth) acrylic resin composition in which little coloring is observed and various physical properties are excellent.

[0019]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a combination of a curing agent and a curing accelerator that causes a redox reaction (this curing agent is combined with a first curing agent and ) And a curing agent that does not cause a redox reaction (hereinafter referred to as a second curing agent), and the second curing agent has a 10-hour half-life temperature of a certain temperature higher than the upper limit of the medium temperature. By using an organic peroxide having a width lower than the width, the (meth) acrylic resin composition can be rapidly cured, and the obtained cured resin is hardly colored, and various physical properties can be further improved. And completed the present invention.

That is, in order to solve the above problems, the (meth) acrylic resin composition according to the present invention contains, as a main component, a resin component composed of a polymer and a monomer. Contains a (meth) acrylic polymer as a polymer and a (meth) acrylic monofunctional monomer as a monomer,
An organic peroxide-based first curing agent, and a curing accelerator that causes a redox reaction with the first curing agent, and a 10-hour half-life temperature of 60 ° C. that does not cause a redox reaction with the curing accelerator
The following second curing agent is added to the resin component.

In the above (meth) acrylic resin composition, the curing accelerator is an organic acid salt of cobalt.
While being added within the range of 1 to 0.3% by weight,
The second curing agent is used in an amount of 0.3 to 5 with respect to the resin component.
Preferably, it is added within the range of weight%.

Since various components are added to commercially available products of these organic acid salts of cobalt (curing accelerator) and the second curing agent, they are converted to pure products at the time of actual use. It will be added in an amount falling within the above range.

With the above construction, the combination of the first curing agent and the curing accelerator allows the resin composition to be rapidly cured even by heating at an intermediate temperature, and the obtained cured resin has excellent physical properties. be able to. In addition, since a redox reaction with the above-mentioned curing accelerator does not occur as the second curing agent and a 10-hour half-life temperature of 60 ° C. or less is used in combination, the amount of the curing accelerator is used to avoid coloring of the cured resin. Even if the amount is smaller, a decrease in the curing rate and a decrease in the physical properties of the cured resin do not occur. Therefore, a cured resin having excellent physical properties can be produced with high production efficiency.

In the above (meth) acrylic resin composition, it is more preferable that the (meth) acrylic polymer contained in the resin composition has a plurality of polymerizable double bonds in a molecule. . That is, it is more preferable that the (meth) acrylic polymer has a crosslinking property. Thereby, the physical properties of the obtained cured resin can be further improved.

Further, the above (meth) acrylic resin composition is more preferably used for a gel coat formed as an outer layer on the surface of a molded product. Gel coat is often formed by medium temperature heat curing, and the cured resin is not colored, and further higher physical properties are required,
This is an application in which the resin composition according to the present invention can be suitably used.

Next, the resin composition of the present invention and the curing method of the present invention will be described in detail below.

The (meth) acrylic resin composition according to the present invention contains a resin component as a main component. In the resin component, component A: (meth) acrylic polymer, and component B: (meth) The total content of the acrylic monofunctional monomer is 50% by weight or more, and as a curing agent,
It contains a first curing agent that causes a redox reaction with a curing accelerator, and a second curing agent that does not cause a redox reaction with the curing accelerator and has a 10-hour half-life temperature of 60 ° C. or less.

The (meth) acrylic resin composition includes:
Other components, for example, component C: an aromatic vinyl monomer and / or component D: a polyfunctional monomer, or various additives may be contained as a resin component, but are not particularly limited. Absent. In other words, in the (meth) acrylic resin composition, it can be said that the resin component composed of at least the component A and the component B is the main component.

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

In the following description, a component composed of a polymer and a monomer is referred to as a “resin component”, and the resin component includes the above components A and B as essential components, It is assumed that the component C and / or the component D may be added according to.

Further, the resin component is composed of a polymer and a monomer. When the total amount of the polymer component in the resin component is 100% by weight, the content of the (meth) acrylic polymer is The amount is defined as follows: That is, in the total amount of the above polymer components, the content of the (meth) acrylic polymer is in the range of 50% by weight or more and 100% by weight or less, more preferably 60% by weight or more and 1% by weight or less.
00% by weight or less, more preferably 70% by weight or less.
It is in the range of from 100% by weight to 100% by weight, particularly preferably from 80% by weight to 100% by weight.

That is, in the resin component of the present invention,
If necessary, a polymer other than a (meth) acrylic polymer such as a polystyrene polymer or a polyethylene polymer may be contained within a range of less than 50% by weight.

Similarly, when the total amount of the monomer components in the resin component is 100% by weight, the content of the (meth) acrylic monofunctional monomer is defined as follows.
That is, in the total amount of the monomer components, (meth)
The content of the acrylic monofunctional monomer is 50% by weight or more and 1% or more.
00% by weight or less, more preferably 60% by weight or more and 100% by weight or less, still more preferably 70% by weight or more and 100% by weight or less, and particularly preferably 80% by weight or less. Not less than 100% by weight.

That is, in the resin component of the present invention,
If necessary, a monomer other than the (meth) acrylic monofunctional monomer such as styrene may be contained within a range of less than 50% by weight. As described above, the (meth) acrylic resin composition according to the present invention is mainly composed of a (meth) acrylic compound such as a (meth) acrylic polymer or a (meth) acrylic monofunctional monomer. As described later, various properties such as weather resistance, transparency, surface gloss, surface hardness, and appearance of the cured resin product obtained, and appearance can be improved.

The composition of the components A to D in the (meth) acrylic resin composition according to the present invention is represented by "% by weight" contained in this resin component. In the following description, the (meth) acrylic resin composition may be simply referred to as a resin composition.

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

The non-crosslinkable (meth) acrylic polymer is not particularly limited. For example, a polymer 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, either. For example, a polymerizable polymer is obtained 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) acrylic acid ester 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) acrylic acid esters may be used alone or in combination of two or more.

Of the above-exemplified compounds, methyl methacrylate (methyl methacrylate, MMA) and (meth) acrylates containing methyl methacrylate as a main component are particularly preferred. By using methyl methacrylate as a main component, various physical properties such as weather resistance, transparency, surface gloss, and surface hardness of the obtained cured resin,
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 is not particularly limited as long as it is a compound having a polymerizable double bond. 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, physical properties such as solvent resistance and weather resistance 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 a compound having a polymerizable double bond and a carboxyl group in the molecule, and is not particularly limited. 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 use amount of the carboxyl group-containing monomer is not particularly limited, but when a crosslinkable (meth) acrylic polymer is obtained, the amount is preferably 0.5% by weight or less in 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, there is a possibility that the physical properties such as the strength at the time of heating of the obtained cured resin material are reduced. If the amount of the carboxyl group-containing monomer exceeds 50% by weight, the cured resin obtained may have reduced weather resistance and water resistance.

The above monomer component contains a vinyl compound (monomer) containing no carboxyl group, if necessary. The above-mentioned 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 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 because 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 type 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.

As the polymerization method of the above monomer components, for example, 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 (meth) acrylic polymer containing a carboxyl group (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.

As the method for producing the glycidyl group-containing (meth) acrylic polymer and the reaction conditions thereof, the above-described method for producing the carboxyl group-containing (meth) acrylic polymer and the reaction conditions can be applied.

The crosslinkable (meth) acrylic polymer in the present invention is obtained by introducing a polymerizable double bond into the above-mentioned carboxyl group-containing (meth) acrylic polymer using an 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 method (a) includes a carboxyl group-containing (meth)
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 by 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 generation of an interface (crack) in the obtained cured resin can be suppressed.

If the double bond equivalent of the (meth) acrylic polymer is less than 2.0 × 10 ² , the resulting cured resin may have poor surface properties such as surface smoothness and gloss. On the other hand, when the double bond equivalent exceeds 1.0 × 10 ⁵ , the cured resin may have a reduced strength at heat.

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 may be any compound having a polymerizable double bond, and is not particularly limited. 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 methacrylates and styrene monomers are more preferable. Further, among the alkyl methacrylates, methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, and t-butyl methacrylate are more preferable, and methyl methacrylate is particularly preferable. Of the styrene monomers, styrene is particularly preferred. This methyl methacrylate corresponds to component B: (meth) acrylic monofunctional monomer, and styrene corresponds to component C: aromatic vinyl monomer.

One of these vinyl monomers may be used alone, or two or more thereof may be used in combination. Thereby, various physical properties such as weather resistance, transparency and surface gloss, appearance, and safety of the obtained cured resin 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 (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.

Examples of the metal compound include 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.

As the inorganic metal compound, 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 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, the time required for the esterification reaction can be reduced, and therefore, tetraphenylphosphonium salts are more preferred, and tetraphenylphosphonium bromide is particularly preferred.

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 carrying out 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 the range of 1-2. Can be adjusted.

The amount of the catalyst to be used may be set according to the type thereof, the combination with the (meth) acrylic polymer containing a carboxyl group, and 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 (meth) acrylic resin composition according to the present invention, as the component A: (meth) acrylic polymer, the non-crosslinkable or crosslinkable (meth) acrylic polymer obtained by the above method is used. Alternatively, these non-crosslinkable 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 (meth) acrylic acid ester 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 properties of the obtained cured resin are sufficiently improved (especially when used for gel coating), the resin component (polymer and monomer) is used. ) Is 100% by weight, the component A in the resin component: the composition of the (meth) acrylic polymer is preferably in the range of 5% by weight or more and 40% by weight or less, more preferably 10% by weight or more. More preferably, it is within the range of 30% by weight or less.

If the content of the component A in the resin component: (meth) acrylic polymer is less than 5% by weight, when the cured resin is formed into a thin film such as a gel coat, There is a problem that the film forming property is poor. On the other hand, if it exceeds 40% by weight, for example, the foam removal property after applying the resin composition to form a gel coat is inferior.

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 (meth) acrylic syrup has a component B: a (meth) acrylic monofunctional monomer, a component C: an aromatic vinyl monomer and / or a component D: a polyfunctional monomer. And a monomer. In this case, the (meth) acrylic syrup itself may be regarded as the above-mentioned resin component in the present invention, and the components B to D are appropriately added according to the use of the cured product of the obtained resin composition. By adjusting the above, the resin component in the present invention may be used.

Component B contained in the (meth) acrylic resin composition according to the present invention: The (meth) acrylic monofunctional monomer is not particularly limited, but is specifically described above. (Meth) acrylic monomers used for producing (meth) acrylic polymers can be used. Among them, methyl methacrylate is particularly preferred.

In the (meth) acrylic resin composition according to the present invention, when sufficiently improving the various physical properties of the obtained cured resin (especially when used for gel coating), the above component B: (meth) Acrylic monofunctional monomer is
It is preferable to include as much as possible.

Specifically, 100% by weight of the resin component
In this case, component B in the resin component: (meth)
The content of the acrylic monofunctional monomer is at least 40% by weight or more, preferably in the range of 60% by weight or more and 95% by weight or less. By adding a large amount of (meth) acrylic monofunctional monomer, various physical properties such as surface hardness and weather resistance are improved.

In the (meth) acrylic resin composition according to the present invention, in addition to the above component A: (meth) acrylic polymer and component B: (meth) acrylic monofunctional monomer, preferably C: an aromatic vinyl monomer and / or component D: a polyfunctional monomer is contained.

The component C: the aromatic vinyl monomer is not particularly limited, but specific examples thereof include styrene, vinyltoluene, α-methylstyrene, chlorostyrene, dichlorostyrene and t-styrene. Butylstyrene, vinyltoluene, and the like. Among them, styrene is particularly preferred.

In the (meth) acrylic resin composition according to the present invention, when the physical properties of the cured resin obtained are sufficiently improved (especially when used for gel coating), 100% by weight of the resin component is used. In this case, the content of Component C: aromatic vinyl monomer in the resin component is preferably in the range of 5% by weight to 40% by weight, and more preferably in the range of 10% by weight to 30% by weight. More preferably, it is within.

When the content of the component C: aromatic vinyl compound in the resin component is less than 5% by weight, in the case of forming a gel coat using the resin composition, for example, the foam removal property and the film forming property are improved. No effect. On the other hand, 30
If the content exceeds% by weight, various physical properties such as surface hardness and durability deteriorate.

Component D contained in the (meth) acrylic resin composition for gel coating according to the present invention: The polyfunctional monomer includes a monomer contained in the resin component and a crosslinkable (meth) acrylic polymer. The compound is not particularly limited as long as it is a compound having a plurality of reactive polymerizable double bonds in the molecule. As the polyfunctional monomer, specifically, for example,
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, Neopentyl glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, trimethylol methane tri (meth)
Acrylate, dipentaerythritol tetra (meth)
Acrylate, dipentaerythritol penta (meth)
Acrylate, dipentaerythritol hexa (meth)
Polyfunctional (meth) acrylates such as 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 the (meth) acrylic resin composition according to the present invention, when the physical properties of the cured resin obtained are sufficiently improved (especially when used for gel coating), 100% by weight of the resin component is used. In this case, the content of Component D: polyfunctional monomer in the resin component is preferably in the range of 1% by weight to 20% by weight, and in the range of 5% by weight to 15% by weight. More preferably, it is within. By including the component D: polyfunctional monomer, various physical properties are improved, and in particular, a decrease in surface hardness when the component C: an aromatic vinyl compound is added can be prevented.

If the content of component D: polyfunctional monomer in the resin component is less than 1% by weight, the effect of improving various physical properties cannot be obtained. On the other hand, if it exceeds 20% by weight, the effect of improving various physical properties corresponding to the added amount cannot be obtained, and the physical properties may be reduced. In addition, this component D: polyfunctional monomer,
The crosslinkable (meth) acryl syrup described above may be contained as a vinyl compound.

As described above, the (meth) acrylic resin composition according to the present invention contains at least one of component C: an aromatic vinyl monomer and component D: a polyfunctional monomer. Is preferred. That is, if component C or component D is contained in the resin composition, various physical property improving effects can be obtained, and if both component C and component D are contained, various physical properties are further improved. I do.

In the present invention, a cured resin is obtained by heating and curing the above (meth) acrylic resin composition. In the following description, this curing is performed at a high temperature (here, a temperature exceeding 80 ° C.). ), But under medium temperature conditions (80 ° C. or less here). Specifically, room temperature (or room temperature, usually −10 ° C.
The curing is performed in a medium temperature heat curing system in which the resin composition is heated and cured in a temperature range higher than the above range (about 35 ° C.) but lower than the above high temperature.

In the present invention, the medium temperature is defined as a temperature range of 35 ° C. or more and 80 ° C. or less. The heating and curing temperature of the resin composition in the present invention is preferably in the range of this medium temperature (35 ° C. to 80 ° C.), more preferably in the range of 40 ° C. or more and 80 ° C. or less, more preferably. Is in the range of 50 ° C. or more and 80 ° C. or less.

In the present invention, two types of organic peroxide-based curing agents are used in the above-mentioned medium-temperature curing system. One is an organic peroxide that causes a redox reaction with a curing accelerator (referred to as a first curing agent).
An organic peroxide having a 0 hour half-life temperature of 60 ° C. or lower (hereinafter referred to as a second curing agent). The second curing agent does not cause a redox reaction with the curing accelerator.

Examples of the organic peroxide used as the first curing agent and the second curing agent include diacyl peroxides, peroxyesters, hydroperoxides, dialkyl peroxides, ketone peroxides, and peroxides. Ketal compounds, alkyl perester compounds, percarbonate compounds and the like can be mentioned.

More specifically, first, as the first curing agent,
For example, methyl ethyl ketone peroxide, cyclohexane peroxide, acetylacetone peroxide, acetoacetate ester peroxide, benzoyl peroxide, cumene hydroperoxide and the like can be mentioned.

In the (meth) acrylic resin composition according to the present invention, as the first curing agent, only one kind may be added, or two or more kinds may be added. Further, the first curing agent is further contained in the range of 0.1% by weight or more and 5% by weight or less, more preferably 0.5% by weight or more and 3% by weight or less with respect to the resin component (100% by weight). It is added within the range of not more than% by weight.

When the amount of the first curing agent is less than 0.1% by weight, rapid heat curing at a medium temperature cannot be realized. On the other hand, if the amount of the first curing agent exceeds 5% by weight,
The progress of curing corresponding to the content is not observed, and the physical properties of the obtained cured resin may be reduced.

Since various components are added to the commercial product of the first curing agent, it is necessary to add the first curing agent in an amount that falls within the above range in terms of a pure product at the time of actual use. become.

Next, as the second curing agent, for example, α
Alkyl peresters such as cumyl peroxyneodecanate, t-butylperoxyneodecanate, and t-butylperoxypivalate; percarbonates such as bis (4-t-butylcyclohexyl) peroxydicarbonate; The temperature is not particularly limited as long as the 10-hour half-life temperature is 60 ° C. or lower.

In the (meth) acrylic resin composition according to the present invention, the second curing agent may be added alone or in combination of two or more. Further, the second curing agent is further contained in the range of 0.3% by weight or more and 5% by weight or less, more preferably 0.1% by weight or less, based on the resin component.
It is added within a range of 5% by weight or more and 3% by weight or less.

If the amount of the second curing agent is less than 0.3% by weight, rapid heat curing at a medium temperature cannot be realized. On the other hand, if the amount of the second curing agent exceeds 5% by weight,
The progress of curing corresponding to the content is not observed, and the physical properties of the obtained cured resin may be reduced.

Since various components are added to the commercial product of the second curing agent as well, at the time of actual use, it should be added in an amount within the above range in terms of a pure product. become.

Here, the 10-hour half-life temperature will be described. First, the half-life of an organic peroxide is an index indicating the rate of decomposition of the organic peroxide at a constant temperature. The original organic peroxide is decomposed, and the amount of active oxygen is reduced by half (1/2). )).

Since the organic peroxide is gradually decomposed by heat, the above half-life varies according to the temperature. In the present invention, since the curing is performed in a temperature range of a medium temperature or less, an organic peroxide showing good decomposition at a temperature of a medium temperature or less, that is, an organic peroxide showing a good half-life characteristic at a temperature of a medium temperature or less. Things are needed. In general, a 10-hour half-life is referred to as an index indicating the half-life characteristic. Therefore, it is preferable that the second curing agent used in the present invention has a 10-hour half-life of a medium temperature or lower.

However, the half-life is the time during which the original organic peroxide is reduced by half. Therefore, for example, if the 10-hour half-life temperature of a certain organic peroxide is the upper limit temperature (about 80 ° C.) at a medium temperature, this organic peroxide must have a resin composition unless the temperature actually exceeds the medium temperature. Sufficient curing speed (curing speed with high productivity)
And cannot be cured.

Therefore, in consideration of this point, it is very preferable that the second curing agent used in the present invention has a 10-hour half-life temperature somewhat lower than the upper limit of the medium temperature. Specifically, in view of the results of the examples described later, the 10-hour half-life temperature is preferably 60 ° C or lower, more preferably 56 ° C or lower.

In the present invention, the curing accelerator used in combination with the first curing agent is not particularly limited as long as it is an organic metal salt which causes a redox reaction with an organic peroxide as the first curing agent. Absent. Specific examples of the curing accelerator include, for example, cobalt naphthenate (cobalt naphthonate), cobalt octylate, divalent acetylacetonate cobalt, trivalent acetylacetone cobalt, potassium hexoate, zirconium naphthenate (zirconium naphthenate) Metal) such as zirconium acetylacetonate, zirconium acetylacetonate, vanadium naphthenate (vanadium naphthonate), vanadium octylate (vanadium octonate), vanadium acetylacetonate, vanadium oxide acetylacetonate (vanadyl acetylacetonate), and lithium acetylacetonate Soaps (metal salts of higher organic acids); amines such as dimethylaniline and diethylaniline; vanadium compounds such as vanadium pentoxide; β-diketones; quaternary ammonium salts
Mercaptans; and the like. Among them,
Cobalt naphthenate and cobalt octylate are preferred.

In the (meth) acrylic resin composition according to the present invention, only one kind of the curing accelerator may be added, or two or more kinds thereof may be added. Further, this curing accelerator is further contained in the range of 0.01 to 0.3% by weight, more preferably 0.01 to 0.2% by weight, based on the resin component. It is added within the range.

If the addition amount of the curing accelerator is less than 0.01% by weight, a sufficient redox reaction does not occur between the curing accelerator and the first curing agent, and the curing acceleration effect is hardly obtained. On the other hand, if the amount of the curing accelerator exceeds 0.3% by weight, the resulting cured resin is notably colored, which is not preferable.

[0131] Since various components are added to the commercial products of the above-mentioned curing accelerators, when they are actually used, they are added in amounts within the above range in terms of pure products. Become.

The combination of the first curing agent and the curing accelerator can be variously mentioned, and is not particularly limited. A more preferable combination is, for example, a trade name: Kayamec M ( Ketone peroxide-based chemical agent Akzo) -cobalt octylate,
Trade name: Kayakumen H (hydroperoxide-based, chemical agent Akzo)-vanadium pentoxide, trade name: kayakumen H (cumene hydroperoxide-based, chemical agent Akzo)
-Cobalt octylate, trade name: Curing agent 328E (manufactured by Kayaku Akzo)-Cobalt octylate, trade name: Cadox series (diacyl peroxide-based, manufactured by Kayaku Akzo)
Amines such as dimethylaniline; trade name: Trigonox A29 (peroxy ketal-based curing agent, manufactured by Kayaku Akzo) -quaternary ammonium salt;

It should be noted that among the compounds used as the curing accelerator, curing may be delayed or the curing may be inhibited depending on the combination of the curing agent and the amount added. Therefore, as the combination of the first curing agent and the curing accelerator, it is highly preferable to appropriately select a curing accelerator according to the type (type) of the first curing agent in consideration of molding conditions and the like.

Each of the above-described combinations of the first curing agent and the curing accelerator has its own characteristic associated with curing, and more preferable combinations are appropriately selected according to the desired cured resin. Become. In addition, in view of versatility, for example, methyl ethyl ketone peroxide-based curing agent such as Kayamek M-organic acid salt of cobalt,
Alternatively, a combination of a hardener 328E (manufactured by Kayaku Akzo) and an organic acid salt of cobalt can be more preferably mentioned.

The method of adding the first curing agent-curing accelerator or the second curing agent to the resin composition is not particularly limited, and may be previously blended with the resin composition before curing. However, for example, when a gel coat is applied, the resin composition and the curing agent (curing agent-curing accelerator) may be separately sprayed (for example, when an external mixing spray is used).

Various additives may be added to the (meth) acrylic resin composition according to the present invention. Examples of the additive include, but are not limited to, a thixotropic agent, an auxiliary thixotropic agent, an antifoaming agent, and a pigment.

The thixotropic agent is not particularly limited as long as it gives the viscosity and thixotropic properties required for the resin composition. Specific examples include silica powder, talc powder and mica powder. Examples include powder, glass flakes, metal whiskers, ceramic whiskers, calcium sulfate whiskers, asbestos, smectite, and organic thixotropic agents.

Commercially available thixotropic agents include Reolosil 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.

For example, in the use of forming a gel coat, the amount of the thixotropic agent may vary depending on the shape of the object to be applied, in particular, the height, area, and shape of the vertical surface, the thickness of the applied gel coat, the ambient temperature, and the resin composition. Although it depends on the properties of the resin or the polymer (polymer) contained in the resin composition or the resin composition, it can be defined 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 (meth) acrylic resin composition, the addition of the thixotropic aid can reduce the amount of the thixotropic agent added, and also increases the amount of the thixotropic agent. Can be improved in various physical properties.

Specific examples of the thixotropic aid 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 aid, 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.).

Examples of the acrylates include trade name: Light Acrylate MTG-A (methoxy-triethylene glycol acrylate, manufactured by Kyoeisha Chemical) and 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.

Further, as the above-mentioned epoxy ethers,
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 name: 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 the auxiliary varies depending on the properties of the resin composition and the type of the thixotropic auxiliary. .001-
It is in the range of 5% by weight, preferably in the range of 0.01 to 3% by weight.

The defoaming agent is not particularly limited, but specific examples include BYKA-515 and 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 0.01% by weight to 3.0% when the resin component is 100% by weight.
It is preferably within the range of weight%.

The above-mentioned pigment is appropriately selected for the purpose of improving the decorative properties, aesthetics, and weather resistance of the cured resin, and is not particularly limited. For coloring purposes, such as, titanium white, red iron, 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 The ones used can be mentioned. Also, the amount of addition is not particularly limited.

In addition to the above, 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.

[0152] Examples of the above additives include reinforcing materials, fillers, modifiers, and flame retardants. These additives are appropriately selected according to the intended use of the cured resin, and the types and specific compounds are not particularly limited.

The method for curing the (meth) acrylic resin composition according to the present invention is not particularly limited as long as the (meth) acrylic resin composition is cured by heating at a medium temperature. For example, if the size of the cured resin is relatively small, a method of heating with an oven or the like can be used. If the size of the cured resin is relatively large, a method of heating with a heating furnace (curing furnace) using boiler heat or combustion heat of petroleum can be used.

The cured (meth) acrylic resin formed in the present invention is not particularly limited, and may be a conventionally known one. For example,
An artificial marble molded product obtained by applying the (meth) acrylic resin composition to which the above various additives are added to the surface of the object by a spray gun to form a gel coat can be given. In the application to form such a gel coat,
Usually, middle-temperature heat curing is used, and therefore, the resin composition and the curing method according to the present invention are very preferably used.

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 system, but it is not particularly limited.
The spraying conditions (application conditions) using a spray gun are not particularly limited, but, 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 (meth) acrylic resin composition according to the present invention can exhibit excellent spray properties even under these conditions.

In addition to the above-mentioned spray gun, other methods of forming the gel coat include, in addition to the spray gun, (1) application by brush (for example, application using a brush to apply paint, etc.). (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. However, in view of productivity and versatility, the method using the spray gun is preferable.

The cured (meth) acrylic resin obtained by the present invention is almost colorless and transparent and has excellent physical properties. In the present invention, the physical properties of the cured resin include at least a cured color (color of the cured resin),
Evaluate durability. For durability, specifically,
Examples include heat resistance, water resistance, solvent resistance, weather resistance, and surface hardness.

Further, in the present invention, it is necessary to improve the curing speed by heating at an intermediate temperature. Therefore, in curing the (meth) acrylic resin composition, the curing properties including the curing speed are evaluated. The method for evaluating the curing characteristics is appropriately selected depending on the method for curing the resin composition, the shape of the cured resin, and the like, and is not particularly limited.

Here, the curing time of a usual (meth) acrylic resin composition is approximately 30 minutes in the case of ordinary temperature curing or medium temperature heating curing. Therefore, in the present invention, it is determined that the productivity is reduced when the curing of the resin composition requires 30 minutes or more. Therefore, the curing speed is 3
The time may be 0 minutes or less, and more preferably 20 minutes or less.

In the present invention, as described above, two types of organic peroxide-based curing agents, a first curing agent-curing accelerator and a second curing agent, are used. Since the decomposition rate of these curing agents increases with heating, the curing time can be shortened accordingly. Therefore, it goes without saying that it is preferable to cure at as high a temperature as possible to shorten the curing time. Therefore, the heating temperature for curing the resin composition depends on the properties of the (meth) acrylic resin composition, the type and amount of the curing agent to be used, the curing accelerator, etc., various physical properties of the obtained resin cured product, Furthermore, it may be appropriately determined in consideration of the curing method, the cost required for molding (ie, economic efficiency), and the like.

Since the gelation time can also be an index for judging the productivity, in the present invention, it is determined that the gelation time should be 10 minutes or less.

As described above, the (meth) acrylic resin composition according to the present invention contains a resin component composed of a polymer and a monomer. , A (meth) acrylic monofunctional monomer-containing monomer, further comprising an organic peroxide-based first curing agent, and a curing accelerator that causes a redox reaction with the first curing agent; Does not cause a redox reaction with the curing accelerator,
A second curing agent having a 10-hour half-life temperature of 60 ° C. or lower is added to the resin component. Also,
In the method for curing a (meth) acrylic resin composition according to the present invention, heat curing is progressed at an intermediate temperature by using the above two types of curing agents in combination.

Thus, even if the amount of the curing accelerator is reduced in order to avoid coloring of the cured resin, the curing rate is not reduced and the physical properties of the cured resin are not reduced. The product can be rapidly cured, and the physical properties of the obtained resin cured product can be made excellent.

The (meth) acrylic resin composition of the present invention is preferably (meth) acrylic syrup (both crosslinkable and non-crosslinkable) obtained by partial polymerization of bulk polymerization, and is preferably a crosslinkable (meth) acrylic resin. Syrups are more preferred, but not particularly limited.

[0166]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative 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 “%”.

The curing characteristics, cured color, heat resistance, water resistance, water resistance, weather resistance, solvent resistance, and surface hardness of the cured (meth) acrylic resin were evaluated or measured by the following methods. .

[Curing Properties] In order to judge the productivity, J
According to IS K6901, the curing characteristics (medium temperature heating and curing) of the (meth) acrylic resin composition at 70 ° C. were measured. When the gelation time was 10 minutes or less and the curing time was 30 minutes or less, it was evaluated that curing proceeded sufficiently quickly.

As described above, the curing time varies depending on the curing temperature, the properties of the (meth) acrylic resin composition, the type and amount of the curing agent and curing accelerator used. Therefore, in this case, the curing characteristics were measured at 70 ° C., which is an almost intermediate temperature, within the range of 50 to 80 ° C. (medium temperature), which is the most preferable curing temperature.

[Cured color] The color of the formed gel coat (coloring degree) was visually confirmed. At this time, the case where the gel coat was colorless and transparent was evaluated as ○, and the colored state where blue-violet color of cobalt was developed was evaluated as ×.

[Heat resistance] After the artificial marble molded product on which the gel coat was formed was left in an oven set at 100 ° C. for 5 hours, the appearance of the gel coat was visually checked. At this time, a case where there was no change compared to before leaving, ○, at least one of slight discoloration and change in gloss was confirmed,
If the level reaches a practical level to some extent, significant discoloration and / or significant gloss change is confirmed,
When it did not reach the practical level, it was evaluated as x.

[Water Resistance] After the artificial marble molded product on which the gel coat was formed was left in boiling water for 2 hours, the appearance of the gel coat 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 artificial marble molded product on which the gel coat 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 was visually checked. did. 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 artificial marble molded product on which the gel coat was formed was immersed in acetone for 1 hour, and the appearance of the gel coat 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] A hardness test based on JIS A5400 was performed on the artificial marble molded product on which the gel coat was formed, and the pencil hardness at which a flaw was clearly formed under a load of 1000 g was measured. The surface hardness was evaluated to be sufficient if the pencil hardness was 5H.

Example 1 193 parts of methyl methacrylate (MMA) and methacrylic acid (MAA) 7 were placed in a reaction vessel equipped with a thermometer, a cooling pipe, a gas introduction pipe, and a stirrer.
And 1.5 parts of n-dodecyl mercaptan were charged, and the inside of the reaction vessel was purged with nitrogen gas. Next, these were heated to 80 ° C. while stirring, and azobisisobutyronitrile (AI
BN) was added thereto, and polymerization was carried out for 3 hours while maintaining at 80 ° C.

Then, at the same time as blowing air into the reaction vessel, 0.05 parts of hydroquinone was added to terminate the radical polymerization. Thereafter, 6 parts of glycidyl methacrylate,
After adding 0.2 parts of tetraphenylphosphonium bromide, the temperature was raised to 100 ° C., and the mixture was reacted in an air atmosphere for 5 hours to obtain a crosslinkable (meth) acryl syrup as Component A used in the present invention.

The solid content of the crosslinkable (meth) acrylic syrup (that is, 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} .

The above-mentioned crosslinkable (meth) acrylic syrup (component A) 40 parts, MMA (component B) 30 parts, styrene (S
20 parts of t · component C) and 10 parts of ethylene glycol dimethacrylate (EGDMA · component D) are mixed (these components A to D are collectively used as a resin component, and
Parts), 0.05 parts of cobalt octylate as a curing accelerator and 3 parts of a thixotropic agent (silica powder /
Nippon Aerosil, trade name: Aerosil # 200), 1 part of shaking change assistant (polyethylene glycol # 400 dimethacrylate, manufactured by Kyoeisha Chemical, trade name: Light Ester 9)
EG), 0.3 parts of antifoaming agent (non-silicone antifoaming agent, manufactured by BYK Chemie, product number: BYK A-515), 1 part of first curing agent (trade name: Kayamec M, methyl ethyl ketone peroxide, chemical agent Akzo) Second curing agent (trade name: Kayaester CND, α-cumylperoxyneodecanate, 10-hour half-life temperature of 38 ° C, manufactured by Kayaku Akzo)
Was added and stirred well to obtain a (meth) acrylic resin composition according to the present invention.

It is needless to say that the addition amounts of the first curing agent-curing accelerator and the second curing agent are amounts converted into pure products.

The above resin composition was applied to a gravity spray gun (spray conditions: 1.5 mm in diameter, blowing air pressure 4
kg / cm ² , air consumption 150 liters / min, jetting amount of gel coat 200 ml / min)
The gel coat was applied to an m-square glass plate at a distance of 20 cm 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. The gel coat was cured by heating the glass plate on which the resin composition was applied at 70 ° C. for 30 minutes in an oven. In addition, the curing properties of the resin composition were measured according to JIS K6091.

Next, 100 parts of an unsaturated polyester resin (manufactured by Nippon Shokubai, trade name: Epolak MR-800), 100 parts of aluminum hydroxide (manufactured by Showa Denko, trade name: Heidilite H-320), 1 part of a curing agent (Kayamec M) is cast on a gel coat on the surface of a glass plate,
After heating at 60 ° C. for 2 hours, the mold was removed to obtain an artificial marble molded article with gel coat as a cured resin. Thereafter, various physical properties of the gel coat were evaluated or measured. Table 1 shows the results.
Shown in

[Examples 2 to 5 and Comparative Examples 1 and 2] The same procedures as in Example 1 were carried out except that the respective organic peroxides shown in Table 2 were used in the amounts shown in Table 1 as the second curing agents. In the same manner as in the above, the resin composition was cured to obtain a gel-coated artificial marble molded product as a cured resin, and the curing characteristics of the resin composition were measured. Table 1 shows the evaluation or measurement results of various physical properties. In Table 2, the curing agent component of the commercially available second curing agent, its 10-hour half-life temperature (° C.), and the content (% by weight) of the curing agent component are shown.

[0184]

[Table 1]

[0185]

[Table 2]

[Examples 6 to 11 and Comparative Examples 3 to 5] In Example 1, after using Kayamek M or curing agent 328E as the first curing agent and using Kayaester CND as the second curing agent, The resin composition was cured in the same manner as in Example 1 except that the curing agent and the curing accelerator were added in the amounts shown in Table 3 to obtain a gel-coated artificial marble molded product as a cured resin. The cured properties of the product were measured. Table 3 shows the evaluation or measurement results of various physical properties.
Shown in

[0187]

[Table 3]

Examples 12 to 14 and Comparative Examples 6 to 8
Example 1 was repeated except that Kayamek M was used as the first curing agent, Kayaester CND was used as the second curing agent, and the curing agents and curing accelerators were added in the amounts shown in Table 4. The resin composition was cured in the same manner as in Example 1 to obtain a gel-coated artificial marble molded product as a cured resin, and the curing characteristics of the resin composition were measured. Table 4 shows the evaluation or measurement results of various physical properties.

Example 15 A reaction vessel similar to that of Example 1 was charged with 193 parts of MMA, 7 parts of MAA, and 1.5 parts of n-dodecyl mercaptan, and the inside of the reaction vessel was replaced with nitrogen gas. Next, these were heated to 80 ° C. while stirring, and
One part of BN was added and polymerization was carried out for 3 hours. Then, air is blown into the reaction vessel and hydroquinone 0.05
And the radical polymerization was terminated to obtain a non-crosslinkable (meth) acryl 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 .

A resin composition was obtained and cured in the same manner as in Example 1 except that 40 parts of the above non-crosslinkable (meth) acrylic syrup was used, and an artificial marble with gel coat as a cured resin was obtained. And the curing characteristics of the resin composition were measured. Table 4 shows the evaluation or measurement results of various physical properties.

[0192]

[Table 4]

As shown in Tables 1 to 4, by using a combination of the first curing agent-curing accelerator (cobalt octylate) and the second curing agent together, a sufficiently rapid curing proceeds, The physical properties of the obtained cured resin are also excellent. Specifically, as the second curing agent,
It is understood that those having a 10-hour half-life temperature of 60 ° C. or lower, preferably 56 ° C. or lower are preferable (Examples 1 to 5).

On the other hand, when a 10-hour half-life temperature of more than 60 ° C. was used as the second curing agent (Comparative Examples 1 and 2), the curing did not proceed rapidly and the surface hardness was low. Dropped. In addition, when the second curing agent was not used (Comparative Examples 3 to 5), although the curing speed was improved with an increase in the curing accelerator, various physical properties such as coloring of the cured resin were reduced. Conversely, when either one of the first curing agent and the curing accelerator was used (Comparative Examples 6.7) and when these combinations were not used (Comparative Example 8), sufficient surface hardness was not obtained. . The (meth) acrylic syrup contained in the resin composition was not limited to crosslinkable or non-crosslinkable (Examples 1 and 15).

[0195]

As described above, according to the present invention, when a (meth) acrylic resin composition is cured by using an organic peroxide curing agent, a first curing agent-curing accelerator which causes a redox reaction. And a 10-hour half-life temperature at which the redox reaction does not occur with the curing accelerator and the upper limit of the medium temperature (80
C) is used together with a second curing agent which is lower by at least 20 ° C.

Thus, the (meth) acrylic resin composition can be rapidly cured, and the amount of the curing accelerator can be reduced, so that the resulting cured resin is hardly colored and has a good appearance and decorativeness. The effect is that a resin cured product excellent in the above can be obtained. In addition, since the curing proceeds sufficiently even by reducing the amount of the curing accelerator, various physical properties such as surface hardness do not decrease even when heat-cured under a medium temperature condition, and a resin cured product having excellent physical properties is obtained. It has the effect of being able to do so.

Continued on the front page F term (reference) 4J011 AA05 PA69 PB30 PB38 PC02 PC08 4J015 CA05 CA06 CA07 CA08 CA09 CA15 4J026 AA45 BA05 BA27 BA28 BB01 DB06 DB16 DB32 GA07 4J027 AA01 BA05 BA07 CB04 CB05 CC02 CD08

Claims (4)

[Claims] 1. A resin component comprising a polymer and a monomer as a main component. The resin component contains a (meth) acrylic polymer as a polymer and a monomer as a monomer. A (meth) acrylic monofunctional monomer, an organic peroxide-based first curing agent, and a curing accelerator that causes a redox reaction with the first curing agent; and a 10-hour half-life temperature. A (meth) acrylic resin composition, wherein a second curing agent having a temperature of 60 ° C. or lower is added to the resin component. 2. The method according to claim 1, wherein the curing accelerator is an organic acid salt of cobalt.
The second curing agent is added in an amount of 0.3 to 5% by weight with respect to the resin component.
The (meth) acrylic resin composition according to claim 1, wherein the (meth) acrylic resin composition is added within a range of weight%. 3. The (meth) acrylic resin composition according to claim 1, wherein the (meth) acrylic polymer has a plurality of polymerizable double bonds in a molecule. . 4. The (meth) acrylic resin composition according to claim 1, which is used for a gel coat formed as an outer layer on the surface of a molded product.