JPH1171416A - (meth)acrylic premix, (meth)acrylic smc or bmc, and manufacture of (meth)acrylic artificial marble - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a (meth)acrylic SMC or BMC particularly useful as a material for (meth)acrylic artificial marble, and a method for preparing a (meth) acrylic artificial marble having a high productivity, good appearances, and a high resistance to boiling water. SOLUTION: The (meth)acrylic premix comprises (A) a (meth)acrylic resin composition comprising (a) (meth)acrylate containing an ester group having a cycrohexane ring or a monomer mixture thereof and (b) (meth)acrylic polymer, (B) an inorganic filler and (C) a curing agent comprising a radical polymerization initiator having a ten-hour half-life temperature of 75 deg.C or higher. A (meth) acrylic SMC or BMC comprises the (meth)acrylic premix and (E) a thickener. The method for preparing a (meth)acrylic artificial marble involves curing the (meth)acrylic SMC or BMC under pressure at a high temperature in the range of 100-150 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a (meth) acrylic premix which is useful as a raw material for an acrylic artificial marble having excellent molding processability, good molding appearance and good hot water resistance,
Suitable for high temperature molding, excellent molding processability, good viscosity increase,
It relates to (meth) acrylic SMC or BMC which is particularly useful as a raw material for (meth) acrylic artificial marble, and a method for producing (meth) acrylic artificial marble having high productivity, good molded appearance and good hot water resistance. is there.

[0002]

2. Description of the Related Art A (meth) acrylic artificial marble, in which an inorganic filler such as aluminum hydroxide is blended with a (meth) acrylic resin, has various outstanding functions such as excellent molded appearance, soft touch and weather resistance. It has characteristics, such as counters such as kitchen counters, vanities, waterproof pans,
Other widely used for architectural purposes. These are generally manufactured by a casting method in which a so-called premix in which an inorganic filler is dispersed in a (meth) acrylic syrup is filled in a mold, and this is cured and polymerized at a relatively low temperature.

[0003] For example, Japanese Patent Application Laid-Open No. 61-26605 discloses (meth) containing cyclohexyl methacrylate.
An artificial marble obtained by curing a composition comprising an acrylic syrup, aluminum hydroxide, and a polymerization initiator having a 10-hour half-life temperature of less than 75 ° C. for a long time at a low pressure is disclosed. However, since the composition disclosed herein uses a polymerization initiator having a 10-hour half-life temperature of less than 75 ° C. as a curing agent, the curing requires a long time of 2 hours or more, and the productivity is low. Extremely bad. Therefore, in order to shorten the curing time and increase the productivity, these compositions are used in one part.
Attempting to cure by heating at a temperature of 00 ° C. or higher causes defects such as cracks and whitening to occur in the molded product due to the low decomposition temperature of the curing agent, losing transparency, and a depth peculiar to marble. Feeling disappears.

On the other hand, in order to improve the productivity problem, a sheet molding compound (hereinafter, referred to as SMC) or a bulk molding compound (hereinafter, referred to as BMC) obtained by thickening a resin syrup with a thickener. The production of (meth) acrylic artificial marble by heating and press molding at a high temperature of 100 ° C. or higher has been conventionally studied. For example, JP-A-6-3130
No. 19 discloses a method of producing an artificial marble by heating and pressing at a high temperature of 115 ° C. acrylic BMC obtained by blending aluminum hydroxide with an acrylic syrup containing methyl methacrylate as a main component.

[0005]

However, when an acrylic artificial marble is manufactured by molding at a temperature higher than the boiling point of methyl methacrylate (100 ° C.), vapor of methyl methacrylate is generated in a mold. ,
The surface of the molded product is eroded by the methyl methacrylate vapor, and the gloss of the eroded portion is reduced, which tends to cause a problem of uneven gloss. Such a tendency is particularly remarkable when the curing temperature is increased to further increase the production speed.

Acrylic artificial marble as described in JP-A-6-313019 tends to be inferior in hot water resistance, and is particularly used for bathtubs and the like that require high heat water resistance. Is difficult. Further, the acrylic SMC or BMC described in Japanese Patent Application Laid-Open No. 6-313019 requires a long time (24 hours or more) aging to increase the viscosity, and has a problem that productivity is low. On the other hand, Japanese Patent Application Laid-Open No. 6-219800 discloses an artificial stone on a flat plate for building materials composed of 5 to 15% by weight of an acrylic binder resin using a high boiling point monomer and 85 to 95% by weight of natural stone particles. Have been.
However, the composition disclosed herein does not have a so-called marble-like deep high-grade texture or soft touch due to a large amount of the inorganic filler. Further, since the amount of the inorganic filler is large, the fluidity of the material is poor, and it is difficult to obtain a molded article having a complicated shape.

An object of the present invention is to provide a (meth) acrylic artificial marble having a molded appearance without uneven gloss, excellent in moldability and excellent in hot water resistance, and useful as a raw material for (meth) acrylic artificial marble.
Acrylic premix, suitable for high-temperature molding, excellent in moldability, good viscosity, (meth) acrylic SMC particularly useful as a raw material for (meth) acrylic artificial marble
Another object of the present invention is to provide a BMC and a method for producing a (meth) acrylic artificial marble having high productivity, good molded appearance and hot water resistance.

[0008]

Means for Solving the Problems As a result of studying the above-mentioned problems, the present inventors have found that by adding a (meth) acrylate having an ester group having a specific structure as a (meth) acrylic resin composition, gloss unevenness can be obtained. (Meth) acrylic premix that is useful as a raw material of acrylic artificial marble with excellent molding processability and good hot water resistance, which has no molded appearance, has been added to this (meth) acrylic premix. By containing a viscous agent, a (meth) acrylic SMC or BMC which is particularly suitable as a raw material for a (meth) acrylic artificial marble, which is suitable for high-temperature molding and has excellent moldability, is found, and the productivity is high. The present inventors have found a method for producing a (meth) acrylic artificial marble excellent in molding appearance and hot water resistance, and completed the present invention.

That is, the present invention is directed to containing (meth) acrylate having an ester group having a cyclohexane ring, or a monomer mixture (a) and (meth) acrylic polymer (b) containing the same. It contains 100 parts by weight of the (meth) acrylic resin composition (A), 1 to 500 parts by weight of the inorganic filler (B), and a radical polymerization initiator having a half-life temperature of 75 ° C. or more for 10 hours. The present invention relates to a (meth) acrylic premix comprising 0.01 to 20 parts by weight of a curing agent (C), comprising the (meth) acrylic premix and a thickener. (Meth) acrylic SMC
Also, the present invention relates to a method for producing (meth) acrylic artificial marble, wherein the (meth) acrylic SMC or BMC is heated and pressurized at a temperature in the range of 100 to 150 ° C.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The (meth) acrylic premix of the present invention comprises a (meth) acrylate having an ester group having a bicyclo ring or a monomer mixture (a) and a (meth) acrylic polymer containing the same. A (meth) acrylic resin composition (A) containing the coalescing (b), an inorganic filler (B), and a curing agent (C) containing a radical polymerization initiator having a 10-hour half-life temperature of 75 ° C. or more. ).

A (meth) acrylate having an ester group having a cyclohexane ring, or a (meth) acryl containing the same, which is used as the component (a) constituting the (meth) acrylic resin composition (A) of the present invention. The system monomer mixture is a component for imparting excellent molding processability to the (meth) acrylic premix of the present invention, and imparting a molded article having no uneven gloss and excellent hot water resistance to molded articles. .

As the (meth) acrylate having an ester group having a cyclohexane ring used as the component (a), specifically, for example, cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate, dimethylcyclohexyl ( Meth) acrylate, trimethylcyclohexyl (meth) acrylate,
Tetramethylcyclohexyl (meth) acrylate, 2
-Cyclohexylethyl (meth) acrylate, 4-cyclohexylcyclohexyl (meth) acrylate, and the like, but are not limited thereto. These may be used alone if necessary,
More than one species may be used in combination. In particular, cyclohexyl (meth) acrylate is preferable in terms of cost.

The (meth) acrylate having an ester group having a cyclohexane ring is preferably used in an amount of 10 to 90% by weight in the (meth) acrylic resin composition (A) used in the present invention. When used within this range, the resulting molded article tends to have no gloss unevenness,
Further, the hot water resistance of the molded article tends to be good. The lower limit of the amount of the (meth) acrylate having an ester group having a cyclohexane ring is more preferably 15% by weight or more, and particularly preferably 20% by weight or more. The upper limit is 8
It is more preferably at most 5% by weight, particularly preferably at most 80% by weight.

Other monomers used as component (a) include monofunctional monomers and polyfunctional monomers.

Specific examples of the monofunctional monomer include, for example, methyl methacrylate, alkyl (meth) acrylate having an alkyl group having 2 to 20 carbon atoms, isobornyl (meth) acrylate, glycidyl (meth) acrylate, hydroxyalkyl (Meth) acrylate, tricyclo [5.2.10 ^2,6 ] decanyl (meth) acrylate, 2,2,2-trifluoroethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) Acrylate, (meth) acrylic acid, (meth) acrylic acid metal salt, fumaric acid, fumaric acid ester, maleic acid, maleic acid ester, aromatic vinyl, vinyl acetate, (meth) acrylic amide, (meth) acrylonitrile, chloride Monofunctional monomers such as vinyl and maleic anhydride It is below.

These can be used alone or in combination of two or more, if necessary. However, a (meth) acrylic monofunctional monomer tends to improve the appearance of a molded article obtained. Is preferred.

In particular, the use of methyl methacrylate is preferable because the resulting molded article can be given a depth peculiar to marble and tends to have a good molded appearance. In this case, the amount of methyl methacrylate used is not particularly limited, but the (meth) acrylic resin composition (A)
It is preferable that the content be contained within the range of 50% by weight or less. If used within this range, the resulting molded article tends to have no gloss unevenness. More preferably 40% by weight
It is within the following range, particularly preferably within the range of 35% by weight or less.

Further, it is preferable to include a polyfunctional monomer as the component (a) because the resulting molded article tends to have excellent strength, solvent resistance, heat resistance and the like.

Specific examples of the polyfunctional monomer include:
For example, ethylene glycol di (meth) acrylate,
Propylene glycol di (meth) acrylate, 1,3
-Butylene glycol di (meth) acrylate, 1,4
-Butylene glycol di (meth) acrylate, 1,6
-Hexanediol di (meth) acrylate, dimethylolethanedi (meth) acrylate, 1,1-dimethylolpropanedi (meth) acrylate, 2,2-dimethylolpropanedi (meth) acrylate, trimethylolethanetri (meth) acrylate A) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylol methane tri (meth) acrylate, tetramethylol methane di (meth) acrylate, neopentyl glycol di (meth) acrylate, and (meth) acrylic acid and polyhydric alcohol [Polyethylene glycol, polypropylene glycol, pentaerythritol, dipentaerythritol, etc.] and polyfunctional esters, divinylbenzene, triaryl isocyanurate, aryl (meth) acrylate, etc. Monomers. These may be used alone if necessary, or two or more of them may be used in combination.

In particular, the use of neopentyl glycol dimethacrylate and / or 1,3-butylene glycol dimethacrylate as a polyfunctional monomer can provide a molded article having an extremely excellent surface gloss, This is preferable because the hot water resistance tends to be good. In this case, neopentyl glycol dimethacrylate and / or 1,3-butylene glycol dimethacrylate may be used in combination with another polyfunctional monomer.

The content of these polyfunctional monomers is not particularly limited. However, in order to obtain the above-mentioned effects effectively, one component should be contained in the component (A) constituting the (meth) acrylic premix of the present invention. Preferably, it is used in the range of 50 to 50% by weight. It is more preferably in the range of 3 to 40% by weight, particularly preferably in the range of 5 to 30% by weight.

The (meth) acrylic polymer used as the component (b) of the (meth) acrylic resin composition (A) of the present invention is obtained by polymerizing a (meth) acrylic monomer as a main component. It is a polymer.

As the polymerization monomer used for obtaining the (meth) acrylic polymer (b), for example, various monomers exemplified as the component (a) can be used as they are. it can. These various monomers may be used alone to obtain a homopolymer as needed, or a copolymer may be obtained by using two or more kinds in combination, and if necessary, furthermore, a multipolymer may be obtained. A crosslinked polymer may be obtained by copolymerizing a functional monomer.

The component (b) may be a cross-linked polymer or a non-cross-linked polymer, and can be appropriately selected as needed. The fluidity of the obtained (meth) acrylic premix and mechanical properties of the molded product Taking strength into account, its weight average molecular weight is in the range of 15,000 to 300,000, more preferably in the range of 25,000 to 250,000. The lower limit of the weight average molecular weight of the component (b) is 25,000.
It is more preferably 0 or more, and the upper limit is more preferably 250,000 or less.

The component (b) is a solution polymerization method, a bulk polymerization method,
It can be produced by a known polymerization method such as an emulsion polymerization method or a suspension polymerization method.

To obtain the (meth) acrylic premix of the present invention, the (meth) acrylic resin composition (A)
The amounts of the components (a) and (b) may be appropriately selected and used, and are not particularly limited.

Considering the workability of the (meth) acrylic premix of the present invention, and the physical properties such as the mechanical strength when this (meth) acrylic premix is used as a raw material for a (meth) acrylic artificial marble. When added, the amount of the component (a) used is preferably in the range of 10 to 90% by weight in the (meth) acrylic resin composition (A). The lower limit of the amount of the component (a) used is more preferably at least 15% by weight,
0% by weight or more is particularly preferred. Further, the upper limit of the amount of the component (a) used is more preferably 85% by weight or less, particularly preferably 80% by weight or less.

Further, the workability of the (meth) acrylic premix of the present invention and the physical properties such as mechanical strength when this (meth) acrylic premix is used as a raw material of a (meth) acrylic artificial marble. Taking into account,
The use amount of the component (b) is preferably in the range of 10 to 90% by weight in the (meth) acrylic resin composition (A).
The lower limit of the use amount of the component (b) is more preferably 15% by weight or more, and particularly preferably 20% by weight or more. (B)
The upper limit of the use amount of the component is more preferably 85% by weight or less, and particularly preferably 80% by weight or less.

In the present invention, the (meth) acrylic resin composition (A) may be a component obtained by dissolving the component (b) in the component (a) or by partially polymerizing the component (a). The polymer (b), which is a polymer thereof, may be produced in the component (a), or the component (a) may be added to the partially polymerized product, or the polymer (b) may be further added to the partially polymerized product. ) Components may be added.

The inorganic filler (B), which is a component (B) constituting the (meth) acrylic premix of the present invention, is not particularly limited, but specific examples thereof include aluminum hydroxide, silica, and fused silica. , Calcium carbonate, barium sulfate, titanium oxide, calcium phosphate, talc, mica, clay, glass powder and the like. Especially,
When the (meth) acrylic premix of the present invention is used as a molding material for artificial marble, the inorganic filler (B)
As, aluminum hydroxide, silica, fused silica,
Calcium carbonate and glass powder are preferred.

In the present invention, the amount of the component (B) used is
It is in the range of 1 to 500 parts by weight based on 100 parts by weight of the (meth) acrylic resin composition (A). By setting the amount to be 1 part by weight or more, the hot water resistance of the obtained molded article becomes good and the linear shrinkage tends to be low. When the amount is 500 parts by weight or less, the molded article tends to have a marble-like deep and good texture. The lower limit of the amount of the component (B) used is 50.
It is more preferably at least 100 parts by weight, particularly preferably at least 100 parts by weight. The upper limit of the amount of the component (B) used is more preferably 350 parts by weight or less, particularly preferably 250 parts by weight or less.

The curing agent as the component (C) constituting the (meth) acrylic premix of the present invention has a temperature of 75 ° C. or higher.
It is essential to contain a radical polymerization initiator having a 0 hour half-life temperature. By using a radical polymerization initiator having a 10-hour half-life temperature of 75 ° C. or more, the storage stability of the (meth) acrylic premix of the present invention tends to be good. Transparency tends to be high.

From the viewpoint that the curing time can be shortened, it is preferable to use a radical polymerization initiator having a 10-hour half-life temperature of 125 ° C. or less. The lower limit of the 10-hour half-life temperature of the radical polymerization initiator is more preferably 80 ° C or higher, particularly preferably 85 ° C or higher. The upper limit of the 10-hour half-life temperature of the component (C) is more preferably 120 ° C. or lower, and particularly preferably 115 ° C. or lower.

Specific examples of the radical polymerization initiator having a 10-hour half-life temperature of 75 ° C. or more include, for example, t-butylperoxyisobutyrate (trade name: Perbutyl IB, manufactured by NOF Corporation). Time half-life temperature = 77 ° C.), di-t-butylperoxy-2-methylcyclohexane (manufactured by NOF CORPORATION, trade name Perhexa M)
C, 10-hour half-life temperature = 83 ° C.), 1,1-bis (t
-Amyl peroxy) 3,3,5-trimethylcyclohexane (trade name KD-2, manufactured by Kayaku Akzo Co., Ltd., 10-hour half-life temperature = 86 ° C.), 1,1,3,3-tetramethylbutyl par Oxy-3,3,5-trimethylhexanoate (manufactured by Kayaku Akzo Co., Ltd., trade names KD-78, 10
Time half-life temperature = 86 ° C.), 1,1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane (manufactured by NOF Corporation, trade name: PerhexaTMH, 10-hour half-life temperature = 87 ° C.) ), 1,1-bis (t-hexylperoxy) cyclohexane (manufactured by NOF Corporation, trade name: Perhexa HC, 10-hour half-life temperature = 87 ° C.),
1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane (manufactured by NOF Corporation, trade name: Perhexa 3M, 10-hour half-life temperature = 90 ° C.), 1,1
-Bis (t-butylperoxy) cyclohexane (trade name Perhexa C, manufactured by NOF Corporation, 10 hour half-life temperature = 91 ° C), 2,2-bis (4,4-di-t-butylperoxy) Cyclohexyl) propane (Nippon Yushi Co., Ltd.)
Product name, Pertetra A, 10 hour half-life temperature = 95
C), t-amyl peroxy-3,3,5-trimethylhexanoate (manufactured by Kayaku Akzo Co., Ltd., trade name Kayaester AN, 10-hour half-life temperature = 95 ° C), 1,1-bis ( t-butylperoxy) cyclododecane (trade name Perhexa CD, manufactured by NOF Corporation, 10-hour half-life temperature = 95 ° C), t-hexylperoxyisopropyl carbonate (trade name, Perhexyl I manufactured by NOF Corporation) ,
10 hours half-life temperature = 95 ° C.), diethylene glycol-bis (t-butylperoxycarbonate) (manufactured by Kayaku Akzo Co., Ltd., trade name Kayalen O-50, 10-hour half-life temperature = 97 ° C.), 1,6 -Bis (t-butylperoxycarbonyloxy) hexane (manufactured by Kayaku Akzo Co., Ltd.)
Product name Kayaren 6-70, 10 hour half-life temperature = 97
° C), t-butyl peroxylaurate (trade name: Perbutyl L, manufactured by NOF Corporation, 10 hour half-life temperature =
98 ° C.), t-butyl peroxy-2-ethylhexyl carbonate (trade name: Perbutyl E, manufactured by NOF Corporation, 10-hour half-life temperature = 99 ° C.), t-butylperoxyisopropyl carbonate (NOF Corporation) Manufactured by Perbutyl I, 10 hour half-life temperature = 99 ° C.), t
-Hexyl peroxybenzoate (Nippon Yushi Co., Ltd.)
Perhexyl Z, trade name, 10 hour half-life temperature = 99
C), t-amyl peroxybenzoate (trade name KD-1, manufactured by Kayaku Akzo Co., Ltd., 10-hour half-life temperature = 10)
0 ° C), 2,5-dimethyl-2,5-di (benzoylperoxy) hexane (trade name: Perhexa 25Z, manufactured by NOF Corporation, 10-hour half-life temperature = 100 ° C), t-butylperoxy- 3,3,5-trimethylhexanoate (trade name: Trigonox 42, manufactured by Kayaku Akzo Co., Ltd.)
10-hour half-life temperature = 100 ° C.), t-butyl peroxyacetate (manufactured by NOF CORPORATION, trade name: Perbutyl A)
−50, 10-hour half-life temperature = 102 ° C.), t-butylperoxybenzoate (trade name: Perbutyl Z, manufactured by NOF Corporation, 10-hour half-life temperature = 104 ° C.), 2,2
-Bis (t-butylperoxy) butane (trade name: Perhexa 22, manufactured by NOF Corporation, 10-hour half-life temperature = 103 ° C), n-butyl-4,4-bis (t-butylperoxy) valerate (Manufactured by NOF Corporation, trade name Perhexa V, 10-hour half-life temperature = 105 ° C), dicumyl peroxide (manufactured by NOF Corporation, trade name Parkmill D, 10-hour half-life temperature = 116 ° C), 2,5-dimethyl-2,5-di (t-butylperoxy) hexane (trade name: Perhexa 25B, manufactured by NOF CORPORATION, 10-hour half-life temperature = 118 ° C.), t-butylcumyl peroxide (Japan Made by Yushi Co., Ltd., trade name Perbutyl C, 10
Time half-life temperature = 120 ° C.), 1,3-bis (t-butylperoxyisopropyl) benzene (Perkadox 14, manufactured by Kayaku Akzo Co., Ltd., 10-hour half-life temperature = 121 ° C.), dibutyl par Oxide (manufactured by NOF Corporation, trade name: Perbutyl D, 10-hour half-life temperature =
Organic peroxides such as t-butyl hydroperoxide (trade name: Perbutyl H, manufactured by NOF Corporation, 10-hour half-life temperature = 166.5 ° C.); 2,2-azobis (2,4 -Dimethylvaleronitrile) (trade name V-65, manufactured by Wako Pure Chemical Industries, Ltd., 10-hour half-life temperature = 51)
° C), 2,2'-azobisisobutyronitrile (trade name: V-60, manufactured by Wako Pure Chemical Industries, Ltd., 10-hour half-life temperature = 65 ° C), 1,1'-azobis (cyclohexane-1)
-Carbonitrile) (trade name V, manufactured by Wako Pure Chemical Industries, Ltd.)
-40, 10-hour half-life temperature = 88 ° C.).

In the present invention, the radical polymerization initiator having a 10-hour half-life temperature of 75 ° C. or more may be used alone or in combination of two or more as a curing agent.
It may be used as a curing agent in combination with a radical polymerization initiator having a 10-hour half-life temperature of less than 5 ° C.

Examples of the radical polymerization initiator having a 10-hour half-life temperature of less than 75 ° C. include, for example,
Bis (4-t-butylcyclohexyl) peroxydicarbonate (Perkadox 16, manufactured by Kayaku Akzo Co., Ltd., 10-hour half-life temperature = 44 ° C.), t-butylperoxy-2-ethylhexanoate (Nippon Oil & Fats Co., Ltd.
Made, trade name Perbutyl O, 10 hour half-life temperature = 72
° C), benzoyl peroxide (Chemical Drug Akzo Co., Ltd.)
Manufactured by Kadox B-CH50 (trade name, 10-hour half-life temperature = 72 ° C.), lauroyl peroxide (manufactured by NOF Corporation, trade name: Parloyl L, 10-hour half-life temperature =
61.6 ° C.).

In the present invention, the amount of component (C) used is
It is in the range of 0.01 to 20 parts by weight based on 100 parts by weight of the (meth) acrylic resin composition (A). By setting the amount to be 0.01 part by weight or more, (meth)
The curability of the acrylic premix tends to be sufficient, and when the amount is 20 parts by weight or less, the storage stability of the (meth) acrylic premix tends to be good. The lower limit of the amount of the component (C) used is more preferably 0.1 part by weight or more, and the upper limit is more preferably 10 parts by weight.

The (meth) acrylic premix of the present invention may further contain, in addition to the components (A) to (C), resin particles (D) containing an inorganic filler. By mixing the component (D) with the (meth) acrylic premix of the present invention and molding, a granite-like artificial marble having a stone pattern can be obtained.

The amount of the inorganic filler-containing resin particles (D) is not particularly limited, but is in the range of 0.1 to 200 parts by weight based on 100 parts by weight of the (meth) acrylic premix of the present invention. Is preferred. This is because, by using the inorganic filler-containing resin particles (D) in an amount of 0.1 parts by weight or more, a stone pattern having good design properties tends to be obtained. This is because the kneadability during the production of the acrylic premix tends to be good. The lower limit of the amount of the inorganic filler-containing resin particles (D) is more preferably 1% by weight or more, and the upper limit is more preferably 100% by weight or less.

The resin constituting the inorganic filler-containing resin particles (D) may be any resin as long as it does not dissolve in methyl methacrylate. Examples thereof include a crosslinked (meth) acrylic resin, a crosslinked polyester resin, and a crosslinked styrene resin. it can.

The crosslinked (meth) acrylic resin has a high affinity with the (meth) acrylic resin composition (A) which is a constituent component of the present invention, and a molded article having a beautiful molded appearance without uneven gloss can be obtained. Resins are preferred. This crosslinked (meth) acrylic resin may contain a non-crosslinked (meth) acrylic polymer.

The amount of the inorganic filler constituting the inorganic filler-containing resin particles (D) may range from 1 to 500 parts by weight based on 100 parts by weight of the resin constituting the inorganic filler-containing resin particles. preferable. By using the inorganic filler in an amount of 1 part by weight or more, the heat resistance and the like of the obtained molded article are improved, and by using the inorganic filler in an amount of 500 parts by weight or less, the molded article becomes marble. There is a tendency that it is possible to impart a good texture with a deep tone.

Specific examples of the inorganic filler include:
For example, inorganic fillers such as aluminum hydroxide, silica, fused silica, calcium carbonate, barium sulfate, titanium oxide, calcium phosphate, talc, clay, glass powder and the like can be used as needed. In particular, when producing granite-like artificial marble, it is preferable to use aluminum hydroxide, silica, fused silica, calcium carbonate, or glass powder as the inorganic filler since the manifestation of the effect is excellent.

The method for producing the inorganic filler-containing resin particles (D) is not particularly limited. For example, a resin molded product containing an inorganic filler obtained by polymerization and curing by a hot press method, a casting method, or the like is pulverized. There is a method of classifying by sieving. For example, crushing (meth) acrylic artificial marble,
The use of inorganic filler-containing resin particles obtained by classification is preferred. In the present invention, the inorganic filler-containing resin (D) can be used alone or as a mixture of two or more kinds having different colors and particle sizes. The particle diameter of the inorganic filler-containing resin particles (D) is not particularly limited as long as it is equal to or less than the thickness of the molded article.

The (meth) acrylic premix of the present invention can be used as a (meth) acrylic SMC or BMC by appropriately adding a thickener (E) as necessary.

The thickener (E) used in the case of using a (meth) acrylic SMC or BMC is not particularly limited and can be appropriately selected as needed. The inorganic filler-containing resin particles (D) can also be used as a thickener, and magnesium oxide powder, polymer powder, and the like can be used.

In the present invention, the amount of the thickener (E) used is not particularly limited, but 100 parts by weight of the (meth) acrylic resin composition (A) which is a component of the (meth) acrylic premix of the present invention. It is preferably in the range of 0.1 to 100 parts by weight based on parts. When the amount of the thickener (E) used is 0.1 parts by weight or more, a high thickening effect tends to be exhibited. This is because the dispersibility of the thickener (E) in the mix tends to be good and the cost tends to be advantageous. The lower limit of the amount of the thickener (E) used is more preferably 1 part by weight or more, and the upper limit is more preferably 80 parts by weight or less.

In particular, in order to improve the water resistance of the obtained molded article, it is preferable to use a polymer powder as the thickener (E). The polymer powder referred to here may be a non-crosslinked polymer powder or a crosslinked polymer powder, but is preferably a noncrosslinked polymer powder. This is because the polymer powder is a non-crosslinked polymer powder, whereby a sufficient thickening effect can be obtained in a short time, and a (meth) acrylic SMC or BMC containing this polymer powder can be produced into granite-like artificial marble. This is because, when used, the sharpness of the grain pattern is improved, and the grain pattern tends to be non-uniform. This tendency is considered to be due to the fact that, after the non-crosslinked polymer powder swells in the (meth) acrylic premix, part or all of it immediately dissolves even at room temperature. In the present invention, the non-crosslinked polymer powder,
It is a polymer powder in which at least the surface layer is composed of a non-crosslinked polymer.

As the polymer constituting the polymer powder, various ones can be appropriately selected and used as needed, and are not particularly limited. The appearance of the (meth) acrylic artificial marble of the present invention is not particularly limited. In consideration of the above points, the (meth) acrylic polymer is preferable.

Specific examples of the constituent components of the polymer powder include, for example, an alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms and cyclohexyl (meth).
Acrylate, glycidyl (meth) acrylate, hydroxyalkyl (meth) acrylate, tricyclo [5
.2.1.0 ^2,6 ] decanyl (meth) acrylate,
2,2,2-trifluoroethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, benzyl (meth) acrylate, (meth) acrylic acid,
(Meth) acrylic acid metal salt, fumaric acid, fumarate ester, maleic acid, maleate ester, aromatic vinyl,
Monofunctional monomers such as vinyl acetate, (meth) acrylamide, (meth) acrylonitrile, vinyl chloride, and maleic anhydride; ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate,
1,3-butylene glycol di (meth) acrylate,
1,4-butylene glycol di (meth) acrylate,
1,6-hexanediol di (meth) acrylate, dimethylolethanedi (meth) acrylate, 1,1-dimethylolpropanedi (meth) acrylate, 2,2-
Dimethylolpropanedi (meth) acrylate, trimethylolethanetri (meth) acrylate, trimethylolpropanetri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolmethanedi (meth) acrylate, neopentylglycoldi ( (Meth) acrylates, and polyhydric esters of (meth) acrylic acid with polyhydric alcohols such as poly (ethylene glycol, polypropylene glycol, pentaerythritol, dipentaerythritol, etc.), divinylbenzene, triarylisocyanurate, aryl ( Polyfunctional monomers such as (meth) acrylates; and the like.

These may be polymerized alone or, if necessary, in combination of two or more. However, the monomers constituting the (meth) acrylic premix of the present invention may be used. Taking into account the affinity with the components, (meth) acrylic monomers are preferred.

In particular, the thickener (E) has a bulk density of 0.1 to 0.7 g / ml, an oil absorption of linseed oil of 60 to 200 ml / 100 g, and methyl methacrylate. When a non-crosslinked polymer powder having a swelling degree of 16 times or more is used, a (meth) acrylic SMC or a (meth) acrylic SMC excellent in handleability and productivity is used by using the (meth) acrylic premix of the present invention. B
MC tends to be obtained, and a molded article having good molded appearance is obtained.

This means that the bulk density of the polymer powder is 0.1 g /
By setting the amount to at least ml, the polymer powder is less likely to be scattered, the yield during the production thereof is improved, and the powdering when adding and mixing the polymer powder to the (meth) acrylic premix is reduced, (Meth) acrylic SMC
Alternatively, the workability of BMC tends to be improved, and by setting the bulk density to 0.7 g / ml or less, a sufficient thickening effect can be obtained by using a small amount of polymer powder. It tends to be possible, and the thickening time is short, so that (meth) acrylic SMC or BM
This is because the productivity of C tends to be improved and the cost tends to be more advantageous. The lower limit of this bulk density is 0.15 g / ml.
The above is more preferable, and 0.2 g / ml or more is particularly preferable. The upper limit of the bulk density is more preferably 0.65 g / ml or less, and particularly preferably 0.6 g / ml or less.

Further, by setting the oil absorption of the polymer powder to linseed oil to 60 ml / 100 g or more, a sufficient thickening effect can be obtained for the (meth) acrylic premix by using a small amount of the polymer powder. And the thickening time can be reduced in a short time.
This is because the productivity of the acrylic SMC or BMC tends to be improved, and the cost tends to be advantageous.
When the content is 100 g or less, the dispersibility of the polymer powder in the (meth) acrylic premix tends to be good.
This is preferable because the kneading properties when producing MC tend to be good. The lower limit of the oil absorption is more preferably 70 ml / 100 g or more, and particularly preferably 80 ml / 100 g or more. The upper limit of the oil absorption is 180 mg / 100.
g or less, and particularly preferably 140 mg / 100 g or less.

Further, by making the swelling degree of the polymer powder to methyl methacrylate 16 times or more,
The effect of thickening the (meth) acrylic premix tends to be sufficient. This swelling degree is more preferably 20 times or more.

The weight average molecular weight of the polymer powder used as the thickener (E) in the present invention is not particularly limited, but the (meth) acrylic SMC or BMC of the present invention is not particularly limited.
Is used in the production of granite-like artificial marble, which can provide a sufficient thickening effect in a short time, and has good sharpness of the stone pattern, and has no unevenness of the stone pattern, the weight average of the polymer powder The molecular weight is preferably in the range of 100,000 to 2,000,000. The lower limit of the weight average molecular weight is more preferably 300,000 or more, and particularly preferably 400,000 or more. The upper limit of the weight average molecular weight is more preferably 1.5 million or less, and particularly preferably 1,000,000 or less.

The specific surface area of the polymer powder used as the thickener (E) in the present invention is not particularly limited, but is preferably in the range of 1 to 100 m ² / g. This is because, by setting the specific surface area of the polymer powder to 1 m ² / g or more, a sufficient thickening effect can be obtained by using a small amount of the polymer powder, and the viscosity can be increased in a short time. Properties are improved, and the polymer powder contains (meth)
When using the acrylic SMC or BMC in granite finished artificial marble manufacture, the better the sharpness of pebbled pattern, tend to pattern non-uniformity of the pebble is lost, also, 100 m ²
/ G or less, the dispersibility of the polymer powder in the (meth) acrylic premix becomes good, so that the kneading property when producing the (meth) acrylic SMC or BMC tends to be good. Because there is. The lower limit of the specific surface area 3m ² or more preferably, 5 m ² or more is particularly preferable.

The average particle size of the polymer powder is not particularly limited, but is preferably in the range of 1 to 250 μm. This is because, by setting the average particle diameter to 1 μm or more, powdering of the polymer powder is reduced, and the handleability of the polymer powder tends to be good. This is because the appearance, particularly the gloss and the surface smoothness, tend to be good. The lower limit of the average particle diameter is more preferably 5 μm or more,
0 μm or more is particularly preferred. Further, the upper limit of the average particle diameter is more preferably 150 μm or less, and particularly preferably 70 μm or less.

The polymer powder used as the thickener (E) in the present invention is preferably a secondary aggregate in which primary particles are aggregated. This is because when the polymer powder has the shape of a secondary aggregate, the absorption rate of the component (a) of the present invention tends to be high, and the viscosity tends to be extremely good.

In this case, the average particle size of the primary particles of the polymer powder is preferably in the range of 0.03 to 1 μm. This means that the average particle size of the primary particles is set to 0.
When the thickness is 03 μm or more, the yield at the time of producing the polymer powder as the secondary aggregate tends to be improved,
By setting the particle size to μm or less, a sufficient thickening effect can be obtained by using a small amount of polymer powder, and the thickening time can be reduced in a short time. When a (meth) acrylic SMC or BMC containing this polymer powder is used for the production of granite-like artificial marble as the agent (E), the sharpness of the grain pattern is improved, and the unevenness of the grain pattern is eliminated. This is because there is a tendency. More preferably,
A range of 0.07 to 0.7 μm is more preferable. The lower limit of the average particle diameter of the primary particles is more preferably 0.07 μm or more, and the upper limit is more preferably 0.7 μm or less.

Further, the polymer powder which can be used as the thickener (E) in the present invention is composed of a core phase and a shell phase which are different from each other in the chemical composition, structure, molecular weight and the like of the polymer forming them. Further, a polymer powder having a so-called core / shell structure may be used. In this case, the core phase may be a non-crosslinked polymer or a crosslinkable polymer, but the shell phase is preferably a noncrosslinked polymer.

The constituent components of the core phase and the shell phase of the polymer powder include, for example, the various components listed above as examples of the constituent components of the polymer powder. These may be polymerized alone or, if necessary, in combination of two or more, and may be copolymerized with the monomer component constituting the (meth) acrylic premix of the present invention. It is preferable to use methyl methacrylate as the main component in the shell phase from the viewpoint of increasing the affinity.

The polymer powder which can be used as the thickener (E) in the present invention may contain an inorganic filler. However, in order to increase the thickening effect, it is necessary to use an inorganic filler. It is preferable not to contain a filler.

The method for producing the polymer powder is not particularly limited, and can be obtained by a known method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization, and dispersion polymerization. Among them, a method of obtaining a polymer powder by subjecting an emulsion obtained by emulsion polymerization to a treatment such as spray drying, freeze drying, or salt / acid precipitation is preferable because of good production efficiency.

The (meth) acrylic premix of the present invention may further contain, if necessary, reinforcing fibers such as glass fibers and carbon fibers, coloring agents, low-shrinking agents, polymerization inhibitors, internal mold release agents, and the like. Can be added.

The method of mixing the components for obtaining the (meth) acrylic premix of the present invention is not particularly limited as long as it is a method capable of efficiently mixing a substance having a high viscosity. For example, a kneader, a mixer, a roll, an extruder, or the like can be used. Also, the (meth) acrylic premix of the present invention is thickened to form a (meth) acrylic SMC or B
When obtaining MC, the above-mentioned various known mixing apparatuses can be used. In particular, when using a non-crosslinked polymer having the specific bulk density and oil absorption and swelling degree as a thickener,
The acrylic SMC or BMC of the present invention is thickened to a non-sticky level in a short time and does not require aging, so that various components are uniformly mixed and simultaneously thickened and extruded,
By shaping into a predetermined shape, a (meth) acrylic SMC or BMC can be produced continuously.

The (meth) acrylic premix of the present invention can be directly heat-cured or redox-cured by a casting method, or can be added with the above-mentioned thickener (E) to form a (meth) acrylic SMC. Alternatively, it is possible to cure by heating and pressure after forming BMC. However, from the viewpoint of productivity, a method of curing by heating and pressure after forming (meth) acrylic SMC or BMC is particularly preferable.

The method for producing artificial marble of the present invention comprises the steps of: forming a (meth) acrylic SMC or BMC and then heating and curing the same to produce artificial marble;
It can be manufactured by a known method such as an injection molding method, a transfer molding method, and an extrusion molding method. In this case, the heating temperature is not particularly limited, but is preferably in the range of 100 to 150 ° C. This is because if the heating temperature is 100 ° C. or higher, heating by steam becomes possible, so that the heating cost is reduced,
In addition, the curing time can be shortened, and the productivity tends to increase. On the other hand, when the heating temperature is set to 150 ° C. or lower, the linear shrinkage of the obtained molded article tends to decrease. The lower limit of the heating temperature is more preferably at least 105 ° C, particularly preferably at least 110 ° C. Further, the upper limit of the heating temperature is more preferably 145 ° C. or less, and 140 ° C.
The following are particularly preferred. Further, the upper mold and the lower mold may be heated with a temperature difference within the above-mentioned heating temperature range.

The pressurizing pressure during the production is 1 to 20 M
The range of Pa is preferable. This is because, by setting the pressurizing pressure to 1 MPa or more, the filling property of the (meth) acrylic SMC or BMC into the mold tends to be good.
This is because a good molded appearance without whitening tends to be obtained by setting the pressure to 0 MPa or less. The lower limit of the pressure is more preferably 2 MPa or more, and the upper limit is 1 MPa.
5 MPa or less is more preferable. In the method for producing artificial marble of the present invention, the molding time may be appropriately selected depending on the thickness of the molded article. (Meth) acrylic B of the present invention
The artificial marble obtained by heating and pressurizing MC or SMC has excellent molded appearance and hot water resistance.

[0070]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples. All parts and% in the examples are on a weight basis except for the linear shrinkage (%). -Physical properties of polymer powder Average particle diameter: Measured using a laser diffraction / scattering particle size distribution analyzer (LA-910, manufactured by Horiba, Ltd.). Bulk density: Measured based on JIS R 6126- 1970. Oil absorption: Measured based on JIS K 5101-1991, and the end point was determined to be immediately before the putty-like mass suddenly softened with the last drop of linseed oil. Specific surface area: Measured by a nitrogen adsorption method using a surface area meter SA-6201 (manufactured by Horiba, Ltd.). Weight average molecular weight: measured by GPC (polystyrene conversion). Swelling degree: The polymer powder is charged into a 100 ml measuring cylinder, lightly tapped several times and packed in 5 ml, and then methyl methacrylate cooled to 10 ° C. or less is charged so that the total amount becomes 100 ml, and the whole becomes uniform. Stir quickly. Thereafter, the graduated cylinder was kept in a thermostat at 25 ° C. for 1 hour, and the volume of the polymer powder layer after swelling was determined and indicated by the ratio to the volume before swelling (5 ml). -Physical properties of molded product Hot water resistance: The molded plate was immersed in hot water of 98 ° C for 120 hours, and the color change (whiteness, color difference, yellowing degree) was compared with the plate before immersion.

(1) Production Example of Polymer Powder (P-1) In a reactor equipped with a cooling pipe, a thermometer, a stirrer, a dropping device, and a nitrogen introduction pipe, 925 parts of pure water, sodium alkyldiphenylether disulfonate were added. 5 parts (manufactured by Kao Corporation, trade name: Perex SS-H) and 1 part of potassium persulfate were charged and heated to 70 ° C. while stirring under a nitrogen atmosphere. A mixture consisting of 500 parts of methyl methacrylate and 5 parts of sodium dialkylsulfosuccinate (trade name: Perex OT-P, manufactured by Kao Corporation) was added dropwise over 3 hours, and the mixture was maintained for 1 hour, and further heated to 80 ° C. The emulsion polymerization was terminated by heating and holding for 1 hour to obtain an emulsion having a polymer primary particle diameter of 0.08 μm. The obtained emulsion is spray-dried at an inlet temperature / outlet temperature = 150 ° C./90° C. using an L-8 type spray dryer manufactured by Okawara Kakoki Co., Ltd. to obtain a secondary aggregate having an average particle diameter of 30 μm. A crosslinked polymer powder (P-1) was obtained. The bulk density of the obtained (P-1) is 0.40 g / ml, the oil absorption to linseed oil is 100 ml / 100 g, the degree of swelling to methyl methacrylate is 20 times or more, and the specific surface area is 51%.
m ² / g, and the weight average molecular weight was 600,000.

(2) Production Example of Polymer Powder (P-2) In a reactor equipped with a cooling tube, a thermometer, a stirrer, a dropping device, and a nitrogen introduction tube, 925 parts of pure water, sodium alkyldiphenyl ether disulfonate were added. 5 parts (manufactured by Kao Corporation, trade name: Perex SS-H) and 1 part of potassium persulfate were charged and heated to 70 ° C. while stirring under a nitrogen atmosphere. To this, 149.85 parts of methyl methacrylate, 1,3-
A mixture consisting of 0.15 parts of butylene glycol dimethacrylate and 5 parts of sodium dialkyl sulfosuccinate (trade name: Perex OT-P, manufactured by Kao Corporation) is mixed with 1.5 parts.
After dripping over time, holding for 1 hour, and then dripping 350 parts of methyl methacrylate over 3.5 hours,
After holding for 1 hour, further raising the temperature to 80 ° C., and holding for 1 hour to complete the emulsion polymerization, the primary particle size of the polymer was 0.10 μm.
m of emulsion was obtained. The obtained emulsion was subjected to an inlet temperature / using an O-8 type spray drying apparatus manufactured by Okawara Kakoki Co., Ltd.
Exit temperature = 150 ° C./90° C. Spray drying treatment is performed in the same manner as for the polymer powder (P-1), the average particle diameter of the secondary aggregate particles is 20 μm, the core phase is a crosslinked polymer, and the shell phase is non- A polymer powder (P-2) having a core / shell structure, which is a crosslinked polymer, was obtained. The bulk density of the obtained (P-2) is 0.1.
38 g / ml, and the oil absorption of linseed oil is 10
0 ml / 100 g, the degree of swelling with respect to methyl methacrylate is 20 times or more, and the specific surface area is 51 m ² / g.
And the weight average molecular weight of the shell phase was 600,000.

(3) Production Example of Polymer Powder (P-3) The charged amount of potassium persulfate was 0.25 parts, and the monomers to be dropped were 497.5 parts of methyl methacrylate and 1,3-butylene glycol dimethacrylate. Emulsion polymerization was carried out in the same manner as in the production example of the polymer powder (P-1) except that the mixture was 2.5 parts and 5 parts of sodium dialkylsulfosuccinate, and the primary particle size of the polymer was 0.18 μm. I got an emulsion. The obtained emulsion was spray-dried in the same manner as in Production Example (1) to obtain a crosslinked polymer powder (P-3) having an average particle diameter of the secondary aggregate particles of 18 µm. The bulk density of the obtained (P-3) is 0.38 g / ml.
And the oil absorption of linseed oil is 95 ml / 100
g, and the degree of swelling with respect to methyl methacrylate is 20.
And the specific surface area was 24 m ² / g.

(4) Production Example of Polymethyl Methacrylate (B-1) in (Meth) acrylic Resin Composition 800 parts of pure water was added to a reactor equipped with a cooling pipe, a thermometer, a stirrer, and a nitrogen introduction pipe. , Polyvinyl alcohol (saponification degree 8
After dissolving 1 part of 8% and a degree of polymerization of 1000), a monomer solution in which 400 parts of methyl methacrylate, 2 parts of normal dodecyl mercaptan and 2 parts of azobisisobutyronitrile are dissolved is added, and the mixture is placed under a nitrogen atmosphere. While stirring at 400 rpm, the temperature was raised to 80 ° C. in 1 hour, and the mixture was directly heated for 2 hours. Thereafter, the temperature was raised to 90 ° C., and the mixture was heated for 2 hours.
The mixture was heated to 20 ° C., and the remaining monomers were distilled off together with water to obtain a slurry, thereby completing the suspension polymerization. After filtering and washing the obtained slurry, it was dried with a hot air dryer at 50 ° C. to obtain polymethyl methacrylate (B-1) having an average primary particle diameter of 93 μm. The bulk density of the obtained (B-1) was 0.70 g / ml, and the oil absorption of linseed oil was:
45 ml / 100 g, the swelling degree with respect to methyl methacrylate is 1.2, and the specific surface area is 0.07 m ² /
g, and the weight average molecular weight was 40,000.

(5) Production Example of Polycyclohexyl Methacrylate (B-2) Except for using cyclohexyl methacrylate instead of methyl methacrylate, the same method as in Production Example (4) was used, and the average primary particle diameter was 150 μm. Polycyclohexyl methacrylate (B-2) was obtained. Obtained (B
The bulk density of -2) was 0.71 g / ml, the degree of swelling with linseed oil was 45 ml / 100 g, the degree of swelling with respect to methyl methacrylate was 1.2, and the specific surface area was 0.07 m ² / g. And the weight average molecular weight was 40,000. (6) Production Example of Resin Particles Containing Inorganic Filler The (meth) acrylic monomer composed of 69% by weight of methyl methacrylate and 2% by weight of ethylene glycol dimethacrylate is added to the polymethyl methacrylate obtained in Production Example (4) above. B-1) In 100 parts of the (meth) acrylic resin composition in which 29 parts were dissolved, t-butyl peroxybenzoate (trade name: Perbutyl Z, manufactured by NOF Corporation, 10-hour half-life temperature = 100 hours) as a curing agent After adding 2.0 parts of zinc stearate as an internal mold release agent and 0.25 parts of a white inorganic pigment or a black inorganic pigment as a colorant, aluminum hydroxide (Showa Denko 200 parts of Hygilite H-310 (trade name, manufactured by K.K.), and 30 parts of the polymer powder (P-1) obtained in the above Production Example (1) as a thickener were added. The mixture was kneaded with a kneader for 10 minutes to obtain a (meth) acrylic BMC. Next, this (meth) acrylic BMC is filled into a 200 mm square flat mold and heated and cured at a mold temperature of 130 ° C. and a pressure of 9.8 MPa for 10 minutes. A black (meth) acrylic artificial marble was obtained. The obtained (meth) acrylic artificial marble was pulverized with a crusher to obtain white or black inorganic filler-containing resin particles having an average particle diameter of 350 µm.

Example 1 Cyclohexyl methacrylate (trade name: Acryester C, manufactured by Mitsubishi Rayon Co., Ltd.)
H) 25% part, methyl methacrylate (manufactured by Mitsubishi Rayon Co., Ltd., trade name Acryester M) 23% part, neopentyl glycol dimethacrylate (Shin-Nakamura Chemical Co., Ltd., trade name NK ester NPG) 25 parts, And a (meth) acrylic monomer (a) composed of 2% by weight of ethylene glycol dimethacrylate (manufactured by Mitsubishi Rayon Co., Ltd., Acryester ED), and a poly (b) obtained in Production Example (1) as a component (b). Methyl methacrylate (B-
1) 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane (manufactured by NOF Corporation) as a curing agent in 100 parts of a (meth) acrylic resin composition in which 25 parts were dissolved 2.0 parts of Perhexa 3M (trade name, 10-hour half-life temperature = 90 ° C.) and 0.5 part of zinc stearate as an internal release agent were added, and then aluminum hydroxide was used as an inorganic filler (Showa Denko KK) And 195 parts of trade name (Heidilite H-310), and 25 parts of the polymer powder (P-1) obtained in the above Production Example (1) as a thickener, and kneaded with a kneader for 10 minutes. Thus, a (meth) acrylic BMC was obtained. Obtained (meth) acrylic BMC
Had no stickiness immediately after kneading and had extremely good handleability. Next, the obtained (meth) acrylic B
MC is filled into a molding die, and is heated and cured for 10 minutes under the conditions of an upper die temperature of 140 ° C., a lower die temperature of 125 ° C., and a pressure of 9.8 MPa, and has a thickness of 10 mm and a 200 mm square (meth) acrylic. An artificial marble molded product was obtained. There is no gloss unevenness on the surface of the obtained molded article, the gloss is extremely high,
The molded appearance was extremely good. The color change of the molded product after immersion in hot water was extremely small, and the hot water resistance was extremely good.

Example 2 A (meth) acrylic BM was prepared in the same manner as in Example 1 except that 19 parts of cyclohexyl methacrylate and 29 parts of methyl methacrylate were used.
C was obtained. Table 2 shows the results of the viscosity increase. Next, Example 1
(Meth) acrylic artificial marble was obtained in the same manner as described above.
Table 2 shows the evaluation results of the obtained molded articles.

Example 3 A (meth) acrylic BM was prepared in the same manner as in Example 1, except that 13 parts of cyclohexyl methacrylate and 35 parts of methyl methacrylate were used.
C was obtained. Table 2 shows the results of the viscosity increase. Next, Example 1
(Meth) acrylic artificial marble was obtained in the same manner as described above.
Table 2 shows the evaluation results of the obtained molded articles.

Example 4 As polymer powder (P-2)
(Meth) acrylic BMC was obtained in the same manner as in Example 1 except for using. Table 2 shows the results of the viscosity increase. Next, a (meth) acrylic artificial marble was obtained in the same manner as in Example 1. Table 2 shows the evaluation results of the obtained molded articles.

Example 5 As a polymer powder (P-3)
(Meth) acrylic BMC was obtained in the same manner as in Example 1 except for using. Table 2 shows the results of the viscosity increase. Next, a (meth) acrylic artificial marble was obtained in the same manner as in Example 1. Table 2 shows the evaluation results of the obtained molded articles.

Example 6 A (meth) acrylic monomer (a) composed of 24 parts of cyclohexyl methacrylate, 24 parts of methyl methacrylate, 15 parts of neopentyl glycol dimethacrylate, and 2 parts of ethylene glycol dimethacrylate was added with (b) ) As a curing agent, 1,1-bis (t-butyl par) was used as a curing agent in 100 parts of the (meth) acrylic resin composition in which 35 parts of the polymethyl methacrylate (B-1) obtained in Production Example (1) was dissolved. Oxy) 3,3
After adding 2.0 parts of 5-trimethylcyclohexane (trade name: Perhexa 3M, manufactured by NOF CORPORATION) and 0.5 part of zinc stearate as an internal release agent, aluminum hydroxide (Showa Denko ( 170 parts of Heidilite H-310 (trade name, manufactured by Co., Ltd.) and 70 parts of the black and white inorganic filler-containing resin particles obtained in Production Example (6).
, And 25 parts of the polymer powder (P-1) obtained in the above Production Example (1) as a thickener.
Kneaded for 0 minutes. The obtained stone-grained (meth) acrylic BMC had no stickiness immediately after kneading and had extremely good handleability. Next, a granite-like (meth) acrylic artificial marble molded product was obtained in the same manner as in Example 1. Table 2 shows the evaluation results of the obtained molded articles.

[Comparative Example 1] A (meth) acrylic resin composition was prepared by mixing 48 parts of methyl methacrylate, 25 parts of neopentyl glycol dimethacrylate, 2 parts of ethylene glycol dimethacrylate, and the polymethyl methacrylate obtained in Production Example (1). (B-1) a mixture consisting of 25 parts, except that the curing agent was t-butyl peroxybenzoate (trade name: Perbutyl Z, manufactured by NOF Corporation, 10 hour half-life temperature = 104 ° C.) In the same manner as in Example 1, a (meth) acrylic BMC was obtained. Table 2 shows the results of the viscosity increase. Next, a (meth) acrylic artificial marble was obtained in the same manner as in Example 1. The obtained molded article had uneven gloss and had a poor molded appearance. The color change of the molded product after immersion in hot water was large.

Comparative Example 2 A (meth) acrylic BMC was obtained in the same manner as in Example 1 except that styrene was used instead of cyclohexyl methacrylate and t-butylperoxybenzoate was used as a curing agent. Table 1 shows the results of the viscosity increase. Next, an acrylic artificial marble was obtained in the same manner as in Example 1. The resulting molded article had severe uneven gloss and low gloss, and had a very poor molded appearance.

Comparative Example 3 As a curing agent, 2,2′-azobis (2,4-dimethylvaleronitrile) (trade name V-65, manufactured by Wako Pure Chemical Industries, Ltd., 10-hour half-life temperature =
A molded article was obtained in the same manner as in Example 1, except that 10 parts were used at 51 ° C. and the other compositions were as shown in Table 1. The obtained molded article had extremely low transparency and did not have any deep feeling peculiar to marble.

Comparative Example 4 100 parts of a (meth) acrylic resin composition comprising 33 parts of cyclohexyl methacrylate, 33 parts of sec-butyl methacrylate and 34 parts of polycyclohexyl methacrylate (B-2) obtained in Production Example (5) Benzoyl peroxide as a curing agent (trade name: Kadox B-CH5, manufactured by Kayaku Akzo Co., Ltd.)
3.0 parts, 0.5 part of zinc stearate as an internal release agent, 200 parts of aluminum hydroxide as an inorganic filler, and kneading with a kneader for 10 minutes. To obtain a (meth) acrylic premix. This (meth) acrylic premix was aged at room temperature for 24 hours or more, but did not thicken. This (meth) acrylic premix was filled in a molding die, and a molded product was obtained in the same manner as in Example 1. The obtained molded product was whitened, had low transparency, and did not have a deep feeling peculiar to marble.

[0086]

[Table 1]

Evaluation results

[Table 2]

Thickening of the premix A: The viscosity increased immediately after kneading, and a premix with no stickiness and good handleability was obtained. B: After kneading, it took 24 hours or more to ripen at room temperature to increase the viscosity to a required viscosity. C: After kneading, the mixture was aged at room temperature for 24 hours or more, but did not increase in viscosity.

Depth feeling (transparency) of molded article ：: High transparency and a deep feeling peculiar to marble. Δ: Transparency is low and there is not much deepness peculiar to marble. X: Transparency is extremely low and there is no deep feeling peculiar to marble.

Gloss unevenness of molded product A: There is no gloss unevenness and the gloss is extremely high. ○ +: There is no gloss unevenness, and the gloss is considerably high. ：: No gloss unevenness, high gloss. Δ: Uneven gloss and low gloss. X: The gloss unevenness is severe and the gloss is extremely low.

Hot water resistance of molded article A: Color change was extremely small. ○ +: Color change was very small. ：: The color change was small. X: The color change was large.

[0092]

As is clear from the above embodiments,
By using a (meth) acrylate having an ester group with a specific structure as the (meth) acrylic resin composition, a molded appearance without gloss unevenness is obtained, the hot water resistance is excellent, and the molding processability is excellent. ) It is possible to obtain a (meth) acrylic premix useful as a raw material of an acrylic artificial marble. Further, by adding a polymer powder as a thickening agent to the (meth) acrylic premix, It is possible to obtain a (meth) acrylic SMC or BMC which is suitable for molding and has excellent moldability and is particularly useful as a raw material of a (meth) acrylic artificial marble. ) Acrylic artificial marble has high productivity, excellent molded appearance and hot water resistance, is extremely useful especially for bathtub applications, and is extremely industrially useful. It is such.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI C08L 33/04 C08L 33/04 // C08F 265/06 C08F 265/06 C04B 111: 54 (72) Inventor Yuichiro Kishimoto Nagoya, Aichi 1-60, Sunadabashi, Higashi-ku, Mitsubishi Mitsubishi Rayon Co., Ltd.

Claims (6)

[Claims] (1) It comprises a (meth) acrylate having an ester group having a cyclohexane ring, or a monomer mixture (a) and a (meth) acrylic polymer (b) containing the same. A curing agent (C) containing 100 parts by weight of a (meth) acrylic resin composition (A), 1 to 500 parts by weight of an inorganic filler (B), and a radical polymerization initiator having a 10-hour half-life temperature of 75 ° C. or more. ) 0.01-20
A (meth) acrylic premix comprising parts by weight. 2. The method according to claim 1, wherein the (meth) acrylate having an ester group having a cyclohexane ring is cyclohexyl (meth).
The (meth) acrylic premix according to claim 1, which is an acrylate. 3. The (meth) acrylic premix according to claim 1, further comprising an inorganic filler-containing resin particle (D). 4. A (meth) acrylic SMC or BMC comprising the (meth) acrylic premix according to claim 1 and a thickener (E). 5. The (meth) acrylic SMC according to claim 4, wherein the thickener (E) is a polymer powder.
Or BMC. 6. The (meth) acrylic SM according to claim 4,
A method for producing a (meth) acrylic artificial marble, wherein C or BMC is cured by heating and pressurizing in the range of 100 to 150 ° C.