JP3443012B2 - Method for producing (meth) acrylic premix, (meth) acrylic SMC or BMC, and (meth) acrylic artificial marble - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention is excellent in dimensional stability and hot water resistance, and also excellent in productivity and appearance (meta).
(Meth) acrylic premix that is useful as a raw material for acrylic artificial marble, and (meth) acrylic SMC or BMC that is particularly useful as a raw material for (meth) acrylic artificial marble that is excellent in moldability and thickening Furthermore, the present invention relates to a method for producing a (meth) acrylic artificial marble which has high productivity, good appearance and dimensional stability, and excellent hot water resistance.

[0002]

2. Description of the Related Art (Meth) acrylic artificial marble prepared by blending a (meth) acrylic resin with an inorganic filler such as aluminum hydroxide has various excellent functions such as excellent molding appearance, soft hand and weather resistance. It has characteristics such as counters such as kitchen counters, vanities, waterproof pans,
Widely used for other construction purposes.

[0003]

[Problems to be Solved by the Invention]
No. 05842 discloses tricyclo [5.2.1] as an artificial marble excellent in dimensional stability during molding and hot water resistance.
An artificial marble obtained by injecting a composition comprising syrup containing [0 ^2,6 ] decanyl (meth) acrylate and quartz powder into a molding die and curing the composition is described.

However, the composition described in JP-A-2-305842 has a problem that productivity is low because it requires a long time of 2 hours or more to complete the curing. Further, in order to shorten the curing time, for example, when these compositions are heated at a high temperature of 100 ° C. or higher to be cured, defects such as cracks and whitening occur in the molded product, resulting in transparency and marble. There is a problem that the peculiar sense of depth is reduced.

An object of the present invention is to provide a (meth) acrylic premix useful as a raw material for a (meth) acrylic artificial marble which is excellent in dimensional stability and hot water resistance, and is also excellent in productivity and appearance, and Excellent in moldability and thickening,
A (meth) acrylic SMC or BMC that is particularly useful as a raw material for a (meth) acrylic artificial marble, and a (meth) acrylic artificial marble that has high productivity, good appearance and dimensional stability, and excellent hot water resistance. Is to provide a method for manufacturing the same.

[0006]

Means for Solving the Problems As a result of diligent studies, the inventors of the present invention have an ester group having a specific structure in a (meth) acrylic resin composition which is a raw material for a (meth) acrylic artificial marble ( It was found that the above problems can be solved by containing a (meth) acrylate and using a specific compound as a curing agent, and completed the present invention.

That is, according to the present invention, a (meth) acrylate having an ester group having a tricyclo ring, or a monomer mixture (a) containing the same, and a polymethylmethacrylate or a (meth) acrylic copolymer (b) are used. ) And 100 parts by weight of a (meth) acrylic resin composition (A) containing
It is characterized by comprising 1 to 500 parts by weight of an inorganic filler (B) and 0.01 to 20 parts by weight of a curing agent (C) containing a compound having a 10-hour half-life temperature of 75 ° C. or higher (meta). It's about acrylic premix,
The present invention relates to a (meth) acrylic SMC or BMC containing the acrylic premix and a thickener, and the (meth) acrylic SMC or BM.
The present invention relates to a method for producing a (meth) acrylic artificial marble, characterized in that C is heated and pressed and cured in a range of 100 to 150 ° C.

[0008]

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 tricyclo ring, or a monomer mixture (a) containing the same, and polymethylmethacrylate or It contains a (meth) acrylic resin composition (A) containing a (meth) acrylic copolymer (b), an inorganic filler (B), and a compound having a 10-hour half-life temperature of 75 ° C. or higher. It is composed of a curing agent (C).

A (meth) acrylate having an ester group having a tricyclo ring, which is used as the component (a) constituting the (meth) acrylic resin composition (A), or a (meth) acrylic monomer containing the same. The body mixture is a component for imparting excellent dimensional stability and hot water resistance to the (meth) acrylic premix of the present invention, and further imparting excellent moldability and molding appearance.

Examples of the (meth) acrylate having an ester group having a tricyclo ring used as the component (a) include adamantyl (meth) acrylate and tricyclo [5.2.1.0 ^2,6 ] decanyl ( Examples thereof include, but are not limited to, (meth) acrylate. These may be used alone or in combination of two or more, if necessary, but in terms of cost, tricyclo [5.2.1.0 ^2,6 ] decanyl (Meth) acrylate is preferred.

The (meth) acrylate having an ester group having a tricyclo ring is preferably used in the range of 5 to 90% by weight in the (meth) acrylic resin composition (A) of the present invention. This is because when the amount of the (meth) acrylate having an ester group having a tricyclo ring is set to 5% by weight or more, the linear shrinkage rate at the time of curing is lowered and the gloss unevenness of the obtained molded article is reduced. This is because the hot water resistance of the molded product obtained is good. Also, if the content is 90% by weight or less, the mechanical strength of the obtained molded product will be good. More preferably 10 to 85% by weight,
More preferably, it is in the range of 15 to 80% by weight.

Other monomers used as the component (a) include, for example, (meth) acrylic acid ester having an alkyl group having 1 to 20 carbon atoms, cyclohexyl (meth) acrylate, and isobornyl (meth). ) Acrylate, glycidyl (meth) acrylate, hydroxyalkyl (meth) acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, trifluoroethyl (meth) acrylate, (meth) acrylic acid, metal (meth) acrylate Monofunctional monomers such as salts, fumaric acid, fumaric acid ester, maleic acid, maleic acid ester, aromatic vinyl, vinyl acetate, (meth) acrylic acid amide, (meth) acrylonitrile, vinyl chloride, maleic anhydride Can be mentioned. They are,
If necessary, they may be used alone or in combination of two or more, but (meth) acrylic monofunctional monomers are preferred because the resulting molded article tends to have a good appearance.

Among them, the use of methyl methacrylate is particularly preferable because it gives a molded article a depth peculiar to marble and tends to give a good appearance. In this case, the content of methyl methacrylate is
Although not particularly limited, it is preferably contained in the (meth) acrylic resin composition (A) in an amount of 50% by weight or less. This is because when the content is within this range, the uneven gloss of the resulting molded article tends to decrease. The range is more preferably 40% by weight or less, and particularly preferably 35% by weight or less.

Further, when the acrylic resin composition of the present invention contains a polyfunctional monomer as the component (a),
It is possible to impart excellent strength, solvent resistance, heat resistance, dimensional stability and the like to the obtained molded product.

Examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate and 1,4-butylene glycol di ( (Meth) acrylate, 1,6-hexanediol di (meth) acrylate, dimethylolethanedi (meth) acrylate, 1,1-dimethylolpropane di (meth) acrylate, 2,2-dimethylolpropane di (meth) acrylate , Trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, neopentyl glycol di (meth)
Acrylate and polyfunctional ester of (meth) acrylic acid with polyhydric alcohol such as polyethylene glycol, polypropylene glycol, pentaerythritol, dipentaerythritol, etc., polyfunctional monomer such as divinylbenzene, triaryl isocyanurate, aryl methacrylate, etc. You can raise your body. These may be used alone or in combination of two or more as required.

Above all, by using neopentyl glycol dimethacrylate and / or 1,3-butylene glycol dimethacrylate as the polyfunctional monomer, the obtained molded article is provided with excellent metallic luster and hot water resistance. Their use is particularly preferred because of their tendency.
In this case, other polyfunctional monomers may be used in combination, if necessary.

The content of these polyfunctional monomers is not particularly limited, but in order to effectively obtain the above effects, it is in the range of 1 to 50% by weight in the (meth) acrylic resin composition (A). It is preferable to include in. This is because when the content of the polyfunctional monomer is 1% by weight or more, the resulting molded article has good gloss, strength, dimensional stability, heat resistance and hot water resistance. Further, if the content is 50% by weight or less, the moldability of the (meth) acrylic premix of the present invention becomes good. The range is more preferably 3 to 40% by weight, and particularly preferably 5
Is in the range of up to 30% by weight.

The content of the component (a) is not particularly limited, but the workability of the (meth) acrylic premix of the present invention and the (meth) acrylic premix of this (meth) acrylic premix. Considering physical properties such as mechanical strength when used as a raw material for artificial marble, (meta)
It is preferable that the acrylic resin composition (A) is contained within the range of 10 to 90% by weight. This is because when the content of the component (a) is 10% by weight or more, the fluidity of the (meth) acrylic premix of the present invention becomes good, and the workability is excellent. Further, if the content is 90% by weight or less, the linear shrinkage rate of the obtained molded product at the time of curing can be lowered. The range is more preferably 15 to 85% by weight, particularly preferably 20 to 80% by weight.

The component (b) constituting the acrylic resin composition (A) of the present invention is polymethylmethacrylate or a (meth) acrylic copolymer.

The content of the component (b) is not particularly limited, but the workability of the (meth) acrylic premix of the present invention and the (meth) acrylic premix are used as the (meth) acrylic premix. Considering physical properties such as mechanical strength when used as a raw material of artificial marble, it is 10 to 90.
A weight% range is preferred. This is because by setting the content of the component (b) to 10% by weight or more, the linear shrinkage rate of the obtained molded product at the time of curing can be reduced. Further, when the content is 90% by weight or less, the fluidity of the (meth) acrylic premix of the present invention becomes good, and the workability is excellent. More preferably 15-85% by weight, still more preferably 20-
It is in the range of 80% by weight.

The component (b) may be a cross-linked polymer or a non-cross-linked polymer and can be appropriately selected as needed, but in consideration of the fluidity of the resin composition obtained and the mechanical strength of the molding material. When added, its weight average molecular weight is 15,0.
It is preferably in the range of 00 to 2,000,000. By setting the weight average molecular weight to 15,000 or more, the mechanical strength of the obtained molded article becomes high, and by setting the weight average molecular weight to 2,000,000 or less, the (meth) acrylic premix of the present invention is obtained. This is because the workability is excellent because the fluidity of is good. More preferably, it is in the range of 25,000 to 1,000,000, and the most preferable range is 30,000 to 600,0.
The range is 00.

As the constituent component used in the (meth) acrylic polymer as the component (b), for example, the above monofunctional monomer can be applied as it is. Two or more kinds of the constituents can be used in combination, and the above polyfunctional monomer can be copolymerized as necessary. The component (b) can be produced by a known polymerization method such as a solution polymerization method, a bulk polymerization method, an emulsion polymerization method or a suspension polymerization method.

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

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

The content of the component (B) is 1 to 500 with respect to 100 parts by weight of the (meth) acrylic resin composition (A).
Within the range of parts by weight. This is because when the content is 1 part by weight or more, the heat resistance of the obtained molded product becomes good and the linear shrinkage rate becomes low. Further, if the content is 500 parts by weight or less, the molded product is given a good texture with a marble-like depth. The lower limit of the content of the component (B) is more preferably 50 parts by weight or more, and particularly preferably 100 parts by weight or more. The upper limit of the content of the component (B) is more preferably 350 parts by weight or less, and particularly preferably 250 parts by weight or less.

The curing agent (C) constituting the (meth) acrylic premix of the present invention has a 10-hour half-life temperature of 75.
Contains compounds that are at or above ° C. When such a compound is used as a curing agent, the productivity and appearance of the obtained artificial marble are improved and the storage stability of the (meth) acrylic premix is improved.

Examples of the compound having a 10-hour half-life temperature of 75 ° C. or higher include t-butyl peroxyisobutyrate (trade name Perbutyl IB, manufactured by NOF CORPORATION), 1
0 hour half-life temperature = 77 ° C.), di-t-butylperoxy-2-methylcyclohexane (produced by NOF CORPORATION, trade name Perhexa MC, 10 hour half-life temperature = 83 ° C.),
1,1-bis (t-amylperoxy) 3,3,5-trimethylcyclohexane (manufactured by Kayaku Akzo Co., Ltd., trade name KD-2, 10-hour half-life temperature = 86 ° C.), 1,1,
3,3-Tetramethylbutylperoxy-3,3,5-
Trimethylhexanoate (Kakuyaku Akzo Co., Ltd., trade name KD-78, 10 hour half-life temperature = 86 ° C.), 1,1
-Bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane (NOF CORPORATION, trade name Perhexa TMH, 10 hour half-life temperature = 87 ° C), 1,1-
Bis (t-hexylperoxy) cyclohexane (produced by NOF CORPORATION, trade name Perhexa HC, 10-hour half-life temperature = 87 ° C.), 1,1-bis (t-butylperoxy) trimethylcyclohexane (NOF ( Co., Ltd., trade name Perhexa 3M, 10-hour half-life temperature = 90 ° C.),
1,1-bis (t-butylperoxy) cyclohexane (produced by NOF CORPORATION, trade name Perhexa C, 10-hour half-life temperature = 91 ° C.), 2,2-bis (4,4-di-t-)
Butylperoxycyclohexyl) propane (Nippon Yushi Co., Ltd., trade name Pertetra A, 10 hour half-life temperature =
95 ° C.), t-amylperoxy-3,3,5-trimethylhexanoate (Kayaester AN, manufactured by Kayaku Akzo Co., Ltd., 10-hour half-life temperature = 95 ° C.), 1, 1
-Bis (t-butylperoxy) cyclododecane (Nippon Yushi Co., Ltd., trade name Perhexa CD, 10-hour half-life temperature = 95 ° C.), t-hexyl peroxyisopropyl carbonate (Nippon Yushi Co., Ltd., product Name perhexyl I, 10-hour half-life temperature = 95 ° C.), diethylene glycol-bis (t-butyl peroxycarbonate) (manufactured by Kayaku Akzo Co., Ltd., trade name Kayalen O-50, 10-hour half-life temperature = 97 ° C.) 1,6-bis (t-butylperoxycarbonyloxy) hexane (Kayaku Akzo Co., Ltd.)
Made, brand name Kayaren 6-70, 10 hours half-life temperature = 9
7 ° C.), t-butyl peroxylaurate (manufactured by NOF CORPORATION, trade name Perbutyl L, 10-hour half-life temperature =
98 ° C.), t-butylperoxy-2-ethylhexyl carbonate (NOF CORPORATION, trade name Perbutyl E, 10-hour half-life temperature = 99 ° C.), t-butylperoxyisopropyl carbonate (NOF CORPORATION). Made by trade name Perbutyl I, 10-hour half-life temperature = 99 ° C), t
-Hexyl peroxybenzoate (NOF CORPORATION)
Made, trade name Perhexyl Z, 10 hour half-life temperature = 99
C.), t-amyl peroxybenzoate (manufactured by Kayaku Akzo Ltd., trade name KD-1, 10-hour half-life temperature = 10)
0 ° C.), 2,5-dimethyl-2,5-di (benzoylperoxy) hexane (manufactured by NOF CORPORATION, trade name Perhexa 25Z, 10 hour half-life temperature = 100 ° C.), t-butylperoxy- 3,3,5-trimethylhexanoate (produced by Kayaku Akzo Co., Ltd., trade name Trigonox 42,
10-hour half-life temperature = 100 ° C.), t-butyl peroxyacetate (manufactured by NOF CORPORATION), trade name Perbutyl A
-50, 10 hours half-life temperature = 102 ° C.), t-butyl peroxybenzoate (Nippon Yushi Co., Ltd., trade name Perbutyl Z, 10 hours half-life temperature = 104 ° C.), 2, 2
-Bis (t-butylperoxy) butane (manufactured by NOF Corporation, trade name Perhexa22, 10-hour half-life temperature = 103 ° C), n-butyl-4,4-bis (t-butylperoxy) valerate (Nippon Oil & Fats Co., Ltd., trade name Perhexa V, 10 hours half-life temperature = 105 ° C), Dicumyl peroxide (Nippon Oil & Fats Co., Ltd., trade name Park Mill D, 10 hours half-life temperature = 116 ° C), 2,5-Dimethyl-2,5-di (t-butylperoxy) hexane (manufactured by NOF CORPORATION, trade name Perhexa 25B, 10-hour half-life temperature = 118 ° C.), t-butylcumyl peroxide (Japan Yushi Co., Ltd., trade name Perbutyl C, 10
Time half-life temperature = 120 ° C.), 1,3-bis (t-butylperoxyisopropyl) benzene (manufactured by Kayaku Akzo Co., Ltd., trade name Percadox 14, 10 hour half-life temperature = 121 ° C.), dibutylper Oxide (trade name, Perbutyl D, manufactured by NOF CORPORATION), 10-hour half-life temperature =
Organic peroxide such as 124 ° C.); 2,2-azobis (2,2
4-Dimethylvaleronitrile) (Wako Pure Chemical Industries, Ltd.)
Made, trade name V-65, 10-hour half-life temperature = 51 ° C),
2,2′-azobisisobutyronitrile (manufactured by Wako Pure Chemical Industries, Ltd., trade name V-60, 10-hour half-life temperature = 65)
C.), 1,1′-azobis (cyclohexane-1-carbonitrile) (Wako Pure Chemical Industries, Ltd., trade name V-4
Azo compounds such as 0, 10 hours half-life temperature = 88 ° C.) can be mentioned. These can be used alone or in combination of two or more.

As the component (C), if necessary, a compound having a 10-hour half-life temperature of less than 75 ° C. can be used in combination. This makes it possible to reduce the linear shrinkage rate during curing without impairing the transparency of the obtained molded product. In this case, a compound of 75 ° C or higher and 75 ° C
When the compound of less than is used in combination, the ratio is 75 ° C. or higher compound / less than 75 ° C. compound = 99.99 / 0.01 to 7
The range of 5/25 is preferable, and 99.9 / 0.1-90 /
The range of 10 is more preferable.

Examples of the compound having a 10-hour half-life temperature of less than 75 ° C. include bis (4-t-butylcyclohexyl) peroxydicarbonate (Kayaku Akzo Co., Ltd.).
Made, product name Perkadox 16, 10 hours half-life temperature =
44 ° C.), t-butylperoxy-2-ethylhexanoate (manufactured by NOF CORPORATION, trade name Perbutyl O, 10)
Time half-life temperature = 72 ° C.), benzoyl peroxide (manufactured by Kayaku Akzo Co., Ltd., trade name Cadox B-CH5)
0, 10 hours half-life temperature = 72 ° C.) and the like.

The content of the component (C) is 0.01 to 100 parts by weight of the (meth) acrylic resin composition (A).
It is within the range of 20 parts by weight. This is the content of
When the amount is 01 parts by weight or more, the curability of the (meth) acrylic premix becomes sufficient, and when the amount is 20 parts by weight or less, the storage stability of the (meth) acrylic premix becomes good. . The lower limit of the content of the component (C) is more preferably 0.1 part by weight or more, and the upper limit is more preferably 10 parts by weight.

Further, by blending and molding the (meth) acrylic premix of the present invention with inorganic filler-containing resin particles, a granite-like artificial marble having a stone pattern can be obtained.

The compounding amount of the resin particles containing an inorganic filler is not particularly limited, but the (meth) acrylic premix 100 is used.
It is preferably in the range of 0.1 to 200 parts by weight with respect to parts by weight. This is because by setting the amount of the inorganic filler-containing resin particles to be 0.1 parts by weight or more, a stone pattern with good design can be obtained, and by setting it to 200 parts by weight or less, the (meth) acrylic prepolymer This is because the kneading property during the production of the mix becomes good. More preferably 1 to 1
It is in the range of 00 parts by weight.

The resin constituting the inorganic filler-containing resin particles may be any resin that does not dissolve in methyl methacrylate, and examples thereof include crosslinked (meth) acrylic resin, crosslinked polyester resin and crosslinked styrene resin.
A crosslinked (meth) acrylic resin is preferable because it has a high affinity with the acrylic resin composition (A) of the present invention and a molded article having a beautiful appearance is obtained. The crosslinked (meth) acrylic resin may contain polymethylmethacrylate or a non-crosslinked (meth) acrylic polymer containing methylmethacrylate as a main component.

The inorganic filler constituting the resin particles containing an inorganic filler is preferably used in the range of 1 to 500 parts by weight with respect to 100 parts by weight of the resin. This is because when the amount of the inorganic filler used is 1 part by weight or more, the resulting molded product has good texture and heat resistance, and the amount of the inorganic filler used is 500 parts by weight or less. This is because it is possible to give a molded product a good texture with a marble-like depth.

As the inorganic filler, aluminum hydroxide, silica, fused silica, calcium carbonate, barium sulfate, titanium oxide, calcium phosphate, calcium carbonate,
Inorganic fillers such as talc, clay and glass powder can be appropriately used if necessary. In particular, when producing granite-like artificial marble, as the inorganic filler,
Aluminum hydroxide, silica, fused silica and glass powder are preferred.

The method for producing the resin particles containing an inorganic filler is not particularly limited, but for example, a resin molded product containing an inorganic filler obtained by polymerization and curing by a hot pressing method, a casting method or the like is crushed and classified by a sieve. There is a method of doing. For example, it is preferable to use inorganic filler-containing resin particles obtained by pulverizing and classifying a (meth) acrylic artificial marble.

In the present invention, one kind or two or more kinds of inorganic filler-containing resin particles having different colors and particle sizes can be used. The particle size of the inorganic filler-containing resin particles is not particularly limited as long as it is not more than the wall thickness of the molded product.

The (meth) acrylic premix of the present invention may be heat-cured or redox-cured by a casting method as it is, or after a thickener is added to form a (meth) acrylic SMC or BMC. It may be cured by heating under pressure. Among them, the method of heating and pressurizing after curing the (meth) acrylic SMC or BMC is preferable from the viewpoint of productivity.

The thickening agent used in the case of the (meth) acrylic SMC or BMC is not particularly limited and, for example, magnesium oxide powder or polymer powder can be used. In particular, the polymer powder is preferable because the molded product tends to have excellent water resistance.

The polymer powder that can be used as the thickener is not particularly limited and can be appropriately selected as necessary. For example, the above-mentioned inorganic filler-containing resin particles can be used as the thickener. However, the bulk density is 0.1 to 0.
It is in the range of 7 g / ml, and the oil absorption amount for linseed oil is 6
It is preferable to use a non-crosslinked polymer powder having a swelling degree with respect to methyl methacrylate of 16 times or more in the range of 0 to 200 ml / 100 g. When such a specific polymer powder is used as a thickener, a (meth) acrylic SMC or BMC excellent in handleability and productivity is obtained,
Further, a molded product having a good appearance tends to be obtained.

This is because the bulk density of the polymer powder is 0.1 g /
When the amount is at least ml, the polymer powder is less likely to scatter, the yield at the time of its production is good, and the powdering when adding and mixing the polymer powder to the (meth) acrylic premix is reduced, This is because the property becomes good, and when the amount is 0.7 g / ml or less,
This is because it is possible to obtain a sufficient thickening effect by using a small amount of the polymer powder, and since the thickening can be completed in a short time, the productivity is improved and the cost becomes advantageous. The range is preferably 0.15 to 0.65 g / ml, and more preferably 0.2 to 0.6 g / ml.

By adjusting the oil absorption amount of the polymer powder with respect to the linseed oil to 60 ml / 100 g or more, it is possible to obtain a sufficient thickening effect with the use of a small amount of the polymer powder, and to further increase the viscosity in a short time. This is because the productivity is improved and the cost is also improved.
When the amount is 100 g or less, the dispersibility of the polymer powder in the (meth) acrylic premix becomes good, and the kneading property at the time of producing the (meth) acrylic SMC or BMC becomes good. . Preferably,
It is in the range of 70 to 180 ml / 100 g, and more preferably in the range of 80 to 140 ml / 100 g.

Further, by making the degree of swelling of the polymer powder with respect to methyl methacrylate 16 times or more,
This is because the effect of thickening the (meth) acrylic premix becomes sufficient. It is more preferably 20 times or more.

The polymer powder may be a non-crosslinked polymer powder or a crosslinked polymer powder, but it is preferably a noncrosslinked polymer powder. This is because the polymer powder is a non-crosslinked polymer powder, so that a sufficient thickening effect can be obtained in a short time, and a (meth) acrylic SMC or BMC containing this polymer powder is manufactured into a granite-like artificial marble. This is because when used for, the sharpness of the stone pattern tends to improve and the unevenness of the stone pattern tends to disappear. It is considered that such a tendency is due to that, after the non-crosslinked polymer powder is swollen in the (meth) acrylic premix, a part or all of it is immediately dissolved even at room temperature.

In the present invention, the non-crosslinked polymer powder is a polymer powder in which at least the surface layer portion is composed of the non-crosslinked polymer.

The weight average molecular weight of the polymer powder used in the present invention is not particularly limited, but it is 100,000-2.
It is preferably in the range of, 000,000.

Since the weight average molecular weight is within this range, a sufficient thickening effect can be obtained in a short time, and the (meth) acrylic SMC or BM containing this polymer powder is obtained.
This is because when C is used for producing a granite-like artificial marble, the sharpness of the stone pattern is improved and the unevenness of the stone pattern is eliminated. The range is more preferably 300,000 to 2,000,000, and particularly preferably the range is 400,000 to 1,000,000.

The amount of the polymer powder used in the present invention is not particularly limited, but 0.1 to 100 parts by weight of the polymer powder (A) of the present invention is used in an amount of 0.1 to 50 parts by weight of the polymer powder.
It is preferably in the range of 100 parts by weight. This is because when the amount of the polymer powder used is 0.1 parts by weight or more, a high thickening effect is exhibited, and when it is 100 parts by weight or less, the dispersibility of the polymer powder becomes good, and the cost becomes advantageous. Is. The more preferable amount of the polymer powder used is in the range of 1 to 80 parts by weight.

The specific surface area of the polymer powder used in the present invention is not particularly limited, but it is from 1 to 100.
It is preferably in the range of m ² / g.

This is because the specific surface area of the polymer powder is 1 m ² /
When the amount is at least g, a sufficient thickening effect can be obtained with the use of a small amount of the polymer powder, and the viscosity can be increased in a short time, so that the productivity is improved, and further the polymer powder is contained. When the (meth) acrylic SMC or BMC is used for producing a granite-like artificial marble, the sharpness of the stone pattern is improved, the unevenness of the stone pattern is eliminated, and 100 m ² /
This is because when the content is less than or equal to g, the dispersibility of the polymer powder in the (meth) acrylic premix becomes good, and the kneading property at the time of producing the (meth) acrylic SMC or BMC becomes good. . More preferably 3 to
It is in the range of 100 m ² / g, more preferably 5 to 1
It is in the range of 00 m ² / g.

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 when the average particle size is 1 μm or more, powder dusting is reduced and the handling property of the polymer powder is good, and when it is 250 μm or less, the appearance of the obtained molding material, especially gloss And the surface smoothness is improved. More preferably, 5 to 1
It is in the range of 50 μm, and more preferably 10 to 70.
It is in the range of μm.

The polymer powder used 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 agglomerate, the absorption rate of the component (a) of the present invention is fast and the viscosity increase becomes extremely good.

Further, in this case, the average particle diameter 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 0.
When it is at least 03 μm, the yield at the time of producing the polymer powder which is a secondary agglomerate is good, and when it is at most 1 μm, a sufficient thickening effect can be obtained by using a small amount of the polymer powder, and the thickening Productivity is improved because it is possible in a short time, and further, this polymer powder is included (meta).
This is because when the acrylic SMC or BMC is used for producing a granite-like artificial marble, the sharpness of the stone pattern is improved and the unevenness of the stone pattern is eliminated. More preferably,
It is in the range of 0.07 to 0.7 μm.

As the polymer constituting the polymer powder, various polymers can be appropriately selected and used according to need, and are not particularly limited, but the appearance of the obtained (meth) acrylic artificial marble, etc. Considering the above point, a (meth) acrylic polymer is preferable.

The constituents of the polymer powder include, for example,
Alkyl (meth) having an alkyl group having 1 to 20 carbon atoms
Acrylate, cyclohexyl (meth) acrylate,
Glycidyl (meth) acrylate, hydroxyalkyl (meth) acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, trifluoroethyl (meth) acrylate, (meth) acrylic acid, (meth) acrylic acid metal salt, fumar Examples thereof include acid, fumaric acid ester, maleic acid, maleic acid ester, aromatic vinyl, vinyl acetate, (meth) acrylic acid amide, (meth) acrylonitrile, vinyl chloride and maleic anhydride. These may be polymerized alone or may be used in combination of two or more kinds, if necessary,
The (meth) acrylic monomer is preferable in consideration of the affinity with the monomer components constituting the (meth) acrylic premix.

Further, the polymer powder used in the present invention is
A polymer powder having a so-called core / shell structure composed of a core phase and a shell phase having different chemical compositions, structures, molecular weights and the like of the polymers forming them 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 non-crosslinked polymer.

The constituents of the core phase and shell phase of the polymer powder include, for example, alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms, cyclohexyl (meth) acrylate, glycidyl (meth) acrylate, hydroxyalkyl. (Meth) acrylate, benzyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, trifluoroethyl (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 acid amide, (meth) acrylonitrile, vinyl chloride, maleic anhydride and the like. These may be polymerized singly or may be used in combination of two or more kinds as required, but they have an affinity with the monomer component constituting the (meth) acrylic premix. From the viewpoint of increasing the number, it is preferable to use methyl methacrylate as the main component in the shell phase.

When the core phase is crosslinked, 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-dimethylolpropane di (meth) acrylate, 2,2-dimethylolpropane di (meth) acrylate , Trimethylolethane tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, tetramethylolmethane di (meth) acrylate, neopentyl glycol di (meth)
Acrylate and polyfunctional ester of (meth) acrylic acid with polyhydric alcohol such as polyethylene glycol, polypropylene glycol, pentaerythritol, dipentaerythritol, etc., polyfunctional monomer such as divinylbenzene, triaryl isocyanurate, aryl methacrylate, etc. The body can be used as a constituent component, and these can be used alone or in combination of two or more kinds.

Further, the polymer powder of the present invention may contain an inorganic filler, but it is preferable not to contain the inorganic filler in order to enhance the thickening effect.

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

Further, the acrylic premix of the present invention may contain reinforcing materials such as glass fiber and carbon fiber, if necessary.
Various additives such as a colorant, a low-shrinking agent, a curing agent, and an internal release agent can be added.

The method of mixing the constituents 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 highly viscous substance. For example, a kneader, mixer, roll, extruder or the like can be used.

Further, the (meth) acrylic premix of the present invention is thickened to obtain a (meth) acrylic SMC or BM.
Also when obtaining C, the above-mentioned various mixing devices can be used. In particular, when a non-crosslinked polymer having the above-mentioned specific bulk density, oil absorption and swelling degree is used as a thickener, the acrylic SMC or BMC of the present invention is thickened to a non-sticky level in a short time and aged. Since it is unnecessary, the various components are uniformly mixed, and at the same time thickened and extruded, and shaped into a predetermined shape.
It is also possible to produce C or BMC continuously.

When an artificial marble is produced by heating the (meth) acrylic premix of the present invention into acrylic SMC or BMC and then heating and pressurizing it, a compression molding method, a transfer molding method, an injection molding method, an extrusion method is used. It can be manufactured by a method such as a 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,
By setting the heating temperature to 100 ° C. or higher, it becomes possible to heat with steam, which is advantageous in terms of cost, and the curing time can be shortened, which tends to increase the productivity. By setting the heating temperature to 150 ° C. or lower, This is because the linear shrinkage of the obtained molded product tends to be low. More preferably 105 to 145 ° C, particularly preferably 110 to 1
It is in the range of 40 ° C. Further, the upper mold and the lower mold may be heated with a temperature difference within the above temperature range.

The pressure applied is preferably in the range of 1 to 20 MPa. This is because when the pressurizing pressure is 1 MPa or more, the filling property of the (meth) acrylic SMC or BMC into the mold tends to be good, and when it is 20 MPa or less, no whitening occurs. This is because the molded appearance tends to be obtained. More preferably, 2-15
It is in the range of MPa.

The molding time may be appropriately selected depending on the thickness of the molded product.

(Meth) acrylic BMC or S of the present invention
The artificial marble obtained by heating and curing the MC has excellent molding appearance and hot water resistance, and can have a linear shrinkage of 0.9% or less.

[0069]

EXAMPLES The present invention will be specifically described below with reference to examples. Parts and% in the examples are on a weight basis except for the value of linear shrinkage.

Physical properties of polymer powder Average particle size: Measured using a laser diffraction / scattering type particle size distribution measuring device (LA-910, manufactured by Horiba Ltd.).

Bulk density: JIS R 6126-1970
It was measured based on.

Oil absorption: JIS K 5101-1991
The end point was 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: value measured by GPC method (in terms of polystyrene) Swelling degree: Polymer powder was put into a graduated cylinder of 100 ml, tapped lightly several times to fill 5 ml, and then cooled to 10 ° C. or lower methyl methacrylate. Is added so that the total amount becomes 100 ml, and rapidly stirred so that the whole is uniform. Then, the graduated cylinder was kept in a constant temperature bath at 25 ° C. for 1 hour, and the volume of the polymer powder layer after swelling was determined and shown by the ratio to the volume before swelling (5 ml).

-Measurement of linear shrinkage rate of molded product Measure the actual size (Lmm) of the molded product and measure the mold size (L0m
The degree of contraction with respect to m) was calculated by the following formula.

Linear shrinkage (%) = {(L ₀ −L) / L ₀ } × 100 (%)-Physical properties of molded product Hot water resistance: The molded plate is immersed in hot water at 98 ° C for 120 hours, The color change (whiteness, color difference, yellowing degree) of the plate before immersion was compared.

(1) Production Example of Polymer Powder (P-1) A reactor equipped with a cooling pipe, a thermometer, a stirrer, a dropping device and a nitrogen introducing pipe was charged with 925 parts of pure water and sodium alkyldiphenyl ether disulphonate. (Kao Corporation, trade name Perex SS-H) 5 parts and potassium persulfate 1 part were charged and heated to 70 ° C. with stirring under a nitrogen atmosphere. To this, a mixture of 500 parts of methyl methacrylate and 5 parts of sodium dialkylsulfosuccinate (Kao Corporation, trade name Perex OT-P) was added dropwise over 3 hours, and then the mixture was kept for 1 hour and then heated to 80 ° C. The emulsion was polymerized by heating and holding for 1 hour to obtain an emulsion having a polymer primary particle diameter of 0.08 μm.

The obtained emulsion was subjected to an inlet temperature / outlet temperature = 1 using an L-8 type spray dryer manufactured by Okawara Kakoki Co., Ltd.
50 degreeC / 90 degreeC spray drying process was carried out, and the non-crosslinked polymer powder (P-1) whose average particle diameter of a secondary aggregate particle is 30 micrometers was obtained. The bulk density of the obtained (P-1) was 0.40 g / ml, and the oil absorption amount for linseed oil was 100 ml / 100.
and the degree of swelling with respect to methyl methacrylate is 20.
It was more than double, the specific surface area was 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 pipe, a thermometer, a stirrer, a dropping device and a nitrogen introducing pipe, 925 parts of pure water and sodium alkyldiphenyl ether disulphonate were added. (Kao Corporation, trade name Perex SS-H) 5 parts and potassium persulfate 1 part were charged and heated to 70 ° C. with stirring under a nitrogen atmosphere. To this, 149.85 parts of methyl methacrylate, 1,3-
A mixture of 0.15 parts of butylene glycol dimethacrylate and 5 parts of sodium dialkyl sulfosuccinate (trade name Perex OT-P, manufactured by Kao Corporation) was added to 1.5 parts.
After dropping over a period of time and holding for 1 hour, 350 parts of methyl methacrylate was dropped over a period of 3.5 hours,
Hold for 1 hour, further raise to 80 ° C., hold for 1 hour to complete emulsion polymerization, and the primary particle diameter of the polymer is 0.10 μm.
An m emulsion was obtained.

The obtained emulsion was subjected to an inlet temperature / outlet temperature = 1 using an L-8 type spray dryer manufactured by Okawara Kakoki Co., Ltd.
A polymer powder having a core / shell structure in which the secondary aggregate particles have an average particle diameter of 20 μm, the core phase is a crosslinked polymer, and the shell phase is a non-crosslinked polymer after spray drying treatment at 50 ° C./90° C. ( P-2) was obtained. The bulk density of the obtained (P-2) was 0.38 g / ml, and the oil absorption amount for linseed oil was
100 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 is 0.25 part, the monomer to be dropped is 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 diameter of the polymer was 0.18 μm. An emulsion was obtained. The obtained emulsion was spray-dried in the same manner as in Production Example (1) to obtain a crosslinked polymer powder (P-3) having a secondary aggregate particle average particle size of 18 μm. The bulk density of the obtained (P-3) is 0.38 g / ml.
And the oil absorption for linseed oil is 95 ml / 100
and the degree of swelling with respect to methyl methacrylate is 20.
It was more than double and the specific surface area was 24 m ² / g.

(4) Polymethylmethacrylate (B-
Production example 1) In a reactor equipped with a cooling pipe, a thermometer, a stirrer, and a nitrogen introducing pipe, 800 parts of pure water, polyvinyl alcohol (saponification degree: 8
8%, polymerization degree 1000) 1 part was dissolved, and then a monomer solution in which 400 parts of methyl methacrylate, 2 parts of normaldodecyl mercaptan, and 2 parts of azobisisobutyronitrile were dissolved was added, and under a nitrogen atmosphere, While stirring at 400 rpm, the temperature was raised to 80 ° C. in 1 hour, and heating was continued for 2 hours. After that, the temperature is raised to 90 ° C. and heated for 2 hours, and then further 1
The residual monomer was distilled off together with water by heating to 20 ° C. to obtain a slurry, and the suspension polymerization was completed. The obtained slurry was filtered, washed, and then 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 amount for linseed oil was
45 ml / 100 g, swelling degree to methyl methacrylate is 1.2, specific surface area is 0.07 m ² /
and the weight average molecular weight was 40,000.

(5) Production Example of Resin Particles Containing Inorganic Filler Mixture 100 consisting of 69% methyl methacrylate, 2% ethylene glycol dimethacrylate and 29% polymethyl methacrylate (B-1) obtained in the above Production Example (4).
Part, 2.0 parts of t-butyl peroxybenzoate (manufactured by NOF CORPORATION, trade name Perbutyl Z) as a curing agent,
After adding 0.5 parts of zinc stearate and 0.25 parts of white inorganic pigment or black inorganic pigment as an internal mold release agent, aluminum hydroxide (manufactured by Showa Denko KK,
200 parts of Hydilite H-310 (trade name) was added, and the polymer powder (P-1) 30 obtained in the above Production Example (1) was further added.
Part, and knead with a kneader for 10 minutes to prepare acrylic B
I got MC. Next, a 200 mm square flat mold is filled with acrylic BMC and the mold temperature is 130 ° C. and the pressure is 100.
The acrylic artificial marble having a thickness of 10 mm was obtained by heating and curing under a condition of kg / cm ² for 10 minutes. The obtained acrylic artificial marble was crushed with a crusher to obtain white or black inorganic filler-containing resin particles having an average particle diameter of 350 μm.

Example 1 Tricyclo [5.2.1.0]
^2,6 ] Decanyl methacrylate (Hitachi Chemical Co., Ltd.)
Manufactured by FANCLyl FA-513M (trade name) 25 parts, methyl methacrylate (manufactured by Mitsubishi Rayon Co., Ltd., trade name Acryester M) 23 parts, neopentyl glycol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name NK) Ester NPG) 25 parts, ethylene glycol dimethacrylate (Mitsubishi Rayon Co., Ltd., Acryester ED) 2
Part of the (meth) acrylic monomer (a) component,
As a curing agent, 1,1-bis (t-) was added to 100 parts of a (meth) acrylic resin composition in which 25 parts of the polymethylmethacrylate (B-1) obtained in Production Example (1) was dissolved as the component (b). Butyl peroxy) 3,3,5-trimethylcyclohexane (Nippon Yushi Co., Ltd., trade name Perhexa 3)
M, 2.0 parts of 10-hour half-life temperature = 90 ° C., 0.5 parts of zinc stearate as an internal mold release agent, and then aluminum hydroxide (Showa Denko KK) as an inorganic filler.
Manufactured, trade name Hydilite H-310) 195 parts, and further, 25 parts of the polymer powder (P-1) obtained in the above Production Example (1) as a thickener is added and kneaded with a kneader for 10 minutes. To obtain (meth) acrylic BMC. The obtained (meth) acrylic BMC was not sticky even immediately after kneading and had extremely good handleability.

Next, the obtained (meth) acrylic B
MC is filled in a molding die and heated and cured under conditions of an upper die temperature of 140 ° C., a lower die temperature of 125 ° C. and a pressure of 9.8 MPa for 10 minutes, and a (meth) acryl having a thickness of 10 mm and a size of 200 mm. A system artificial marble molded product was obtained.

The surface of the obtained molded product had no gloss unevenness, the gloss was extremely high, and the appearance was very good.
In addition, the molded product had high transparency and had a marble-like depth. The linear shrinkage of the molded product was as low as 0.80%. Also,
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] Tricyclo [5 ・ 2 ・ 1 ・ 0]
(Meth) acrylic BMC was obtained by the same method as in Example 1 except that ^2,6 ] decanyl methacrylate was 19% and methyl methacrylate was 29%. The results of thickening are shown in Table 1.

Next, a (meth) acrylic artificial marble was obtained in the same manner as in Example 1. Table 1 shows the evaluation results of the appearance, linear shrinkage ratio, and hot water resistance of the obtained molded product.

[Embodiment 3] Tricyclo [5.2.1.0]
(Meth) acrylic BMC was obtained in the same manner as in Example 1, except that ^2,6 ] decanyl methacrylate was 15% and methyl methacrylate was 33%. The results of thickening are shown in Table 1.

Then, a (meth) acrylic artificial marble was obtained in the same manner as in Example 1. Table 1 shows the evaluation results of the appearance, linear shrinkage ratio, and hot water resistance of the obtained molded product.

[Example 4] Tricyclo [5.2.1.0]
(Meth) acrylic BMC was obtained in the same manner as in Example 1 except that ^2,6 ] decanyl methacrylate was 9% and methyl methacrylate was 39%. The results of thickening are shown in Table 1.

Then, a (meth) acrylic artificial marble was obtained in the same manner as in Example 1. Table 1 shows the evaluation results of the appearance, linear shrinkage ratio, and hot water resistance of the obtained molded product.

Example 5 As a polymer powder (P-2)
A (meth) acrylic BMC was obtained by the same method as in Example 1 except that was used. The results of thickening are shown in Table 1.

Then, a (meth) acrylic artificial marble was obtained in the same manner as in Example 1. Table 1 shows the evaluation results of the appearance, linear shrinkage ratio, and hot water resistance of the obtained molded product.

Example 6 Neopentyl glycol dimethacrylate 15%, polymethylmethacrylate (B
(Meth) acrylic BMC was obtained by the same method as in Example 1 except that -1) was 35% and the polymer powder was (P-3). The results of thickening are shown in Table 1.

Then, a (meth) acrylic artificial marble was obtained in the same manner as in Example 1. Table 1 shows the evaluation results of the appearance, linear shrinkage ratio, and hot water resistance of the obtained molded product.

[Embodiment 7] Tricyclo [5.2.1.0]
Instead of ^2,6 ] decanyl methacrylate, tricyclo [5.2.11.0 ^2,6 ] decanyl acrylate (Hitachi Chemical Co., Ltd., trade name Funkryl FA-513A)
A (meth) acrylic BMC was obtained by the same method as in Example 1 except that was used. The results of thickening are shown in Table 1.

Then, a (meth) acrylic artificial marble was obtained in the same manner as in Example 1. Table 1 shows the evaluation results of the appearance, linear shrinkage ratio, and hot water resistance of the obtained molded product.

[Embodiment 8] Tricyclo [5.2.1.0]
^2,6 ] decanyl methacrylate 24 parts, methyl methacrylate 24 parts, neopentyl glycol dimethacrylate 25 parts, ethylene glycol dimethacrylate 2 parts to (meth) acrylic monomer (a) component, (b)
As a component, 100 parts of a (meth) acrylic resin composition in which 25 parts of polymethylmethacrylate (B-1) obtained in Production Example (1) was dissolved, and 1,1-bis (t-
Butylperoxy) 3,3,5-trimethylcyclohexane 2.0 parts, zinc stearate as an internal mold release agent 0.
After adding 5 parts, aluminum hydroxide (manufactured by Showa Denko KK, trade name Heidilite H-31) as an inorganic filler
0) 170 parts and 70 parts in total of the black and white inorganic filler-containing resin particles obtained in the above Production Example (5) were added, and the polymer powder obtained in the above Production Example (1) as a thickener ( P-
1) 25 parts were added and kneaded with a kneader for 10 minutes. The stone-grained (meth) acrylic BMC obtained was not sticky even immediately after kneading, and was extremely easy to handle.

Next, in the same manner as in Example 1, a granite (meth) acrylic artificial marble molded product was obtained. Table 1 shows the evaluation results of the appearance, linear shrinkage ratio, and hot water resistance of the obtained molded product.

Comparative Example 1 The (meth) acrylic resin composition comprises 48 parts of methyl methacrylate, 25 parts of neopentyl glycol dimethacrylate, 2 parts of ethylene glycol dimethacrylate and the polymethyl methacrylate obtained in the above Production Example (1). (Meth) acrylic BMC was obtained in the same manner as in Example 1 except that the mixture was 25 parts of (B-1). The results of thickening are shown in Table 1.

Then, a (meth) acrylic artificial marble was obtained in the same manner as in Example 1. The obtained molded product had uneven gloss and had a poor appearance. The linear shrinkage of the molded product is also 0.9
It was as large as 3%. Further, the color change of the molded product after immersion in hot water was large.

[Comparative Example 2] Tricyclo [5.2.1.0]
(Meth) acrylic BMC was obtained in the same manner as in Example 1 except that styrene was used instead of ^2,6 ] decanyl methacrylate. The results of thickening are shown in Table 1.

Then, a (meth) acrylic artificial marble was obtained in the same manner as in Example 1. The obtained molded product had extremely uneven gloss and low gloss, and had a very poor appearance. Further, the linear shrinkage of the molded product was as large as 0.91%.

[Comparative Example 3] Perhexa 3 as a curing agent
In place of M, benzoyl peroxide (manufactured by Kayaku Akzo Co., Ltd., trade name Cadox B-CH50, 10-hour half-life temperature = 72 ° C.) was used in Example 4 except that 3.0 parts were used in a pure content. A (meth) acrylic premix was obtained by the same method.

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 the depth feeling peculiar to marble.

[0107]

[Table 1]

513M: tricyclo [5.2.1.0]
^2,6 ] Decanyl methacrylate 513A: tricyclo [5.2.1 · 1.0 ^2,6 ] decanyl acrylate MMA: methyl methacrylate NPGDMA: neopentyl glycol dimethacrylate EDMA: ethylene glycol dimethacrylate ST: styrene perhexa 3M: 1 , 1-Bis (t-butylperoxy) 3,3,5-trimethylcyclohexane B-CH50: Thickening of benzoyl peroxide premix A: Thickening immediately after kneading and good handleability without stickiness. A premix was obtained.

B: After kneading, it took 24 hours or more to age at room temperature and increase the viscosity to the required viscosity.

-Non-uniform gloss of molded products ⊚: There is no gloss unevenness and the gloss is extremely high.

◯: No gloss unevenness and high gloss.

Δ: There is uneven gloss and the gloss is low.

X: The uneven gloss is severe and the gloss is extremely low.

・ Deep feeling (transparency) of the molded product ◯: The molded product has a high transparency and a marble-like depth.

X: The molded product was whitened, had low transparency, and did not have the depth feeling peculiar to marble.

· Hot water resistance of molded products A: The color change was extremely small.

◯: The color change was small.

X: The color change was large.

[0119]

As is apparent from the above embodiments,
By containing a (meth) acrylate having an ester group having a specific structure as a (meth) acrylic resin composition and a specific compound as a curing agent, a linear shrinkage rate is small and a molded appearance having no gloss unevenness is obtained. It is possible to obtain a (meth) acrylic premix that is useful as a raw material for a (meth) acrylic artificial marble with excellent molding processability. Furthermore, a polymer as a thickener is added to this (meth) acrylic premix. By including the powder,
It is possible to obtain (meth) acrylic SMC or BMC which is suitable for high-temperature molding and has excellent moldability and is particularly useful as a raw material for a (meth) acrylic artificial marble. The (meth) acrylic artificial marble has high productivity, is excellent in appearance, dimensional stability, and hot water resistance, and is extremely useful particularly for bathtub applications and is very useful industrially.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C08K 3/00 C08K 3/00 C08L 33/00 C08L 33/00 // B29K 33:04 B29K 33:04 105: 06 105: 06 (72) Inventor Yuichiro Kishimoto 4-60 Sunadabashi, Higashi-ku, Nagoya, Aichi Mitsubishi Rayon Co., Ltd. Product Development Research Laboratory (56) Reference JP-A-2-305842 (JP, A) JP-A-61-171713 ( (58) Fields investigated (Int.Cl. ⁷ , DB name) C08F 265/06

Claims (7)

(57) [Claims] 1. A (meth) acrylate having an ester group having a tricyclo ring, or a monomer mixture (a) containing the same, and a polymethyl methacrylate or a (meth) acrylic copolymer (b). (Meth) acrylic resin composition (A) 100 parts by weight, inorganic filler (B) 1
˜500 parts by weight and 0.01 to 20 parts by weight of a curing agent (C) containing a compound having a 10-hour half-life temperature of 75 ° C. or higher, (meth) acrylic premix. 2. A (meth) acrylate having an ester group having a tricyclo ring is tricyclo [5.2.1.0].
The (meth) acrylic premix according to claim 1, which is ^2,6 ] decanyl (meth) acrylate. 3. The (meth) acrylic premix according to claim 2, further comprising inorganic filler-containing resin particles. 4. A (meth) acrylic SMC or BMC comprising the (meth) acrylic premix according to claim 2 and a thickener. 5. The (meth) acrylic SMC or B according to claim 4, wherein the thickener is a polymer powder.
MC. 6. The (meth) acrylic SM according to claim 4.
A method for producing a (meth) acrylic artificial marble, characterized in that C or BMC is heated and pressure cured in the range of 100 to 150 ° C. 7. The (meth) acrylic SM according to claim 4.
A method for producing a (meth) acrylic artificial marble having a linear shrinkage of 0.9% or less, which is characterized in that C or BMC is cured by heating under pressure.