JP3527638B2 - 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 relates to a (meth) acrylic premix useful as a raw material for an acrylic artificial marble having excellent molding processability, molding appearance, and hot water resistance.
Suitable for high temperature molding, excellent moldability, good viscosity increase,
The present invention relates to a (meth) acrylic SMC or BMC that is particularly useful as a raw material for a (meth) acrylic artificial marble, and a method for producing a (meth) acrylic artificial marble that has high productivity and good molding appearance and hot water resistance. is there.

[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. These are generally produced 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 molding die and the resulting mixture is cured and polymerized at a relatively low temperature.

For example, JP-A-61-26605 contains cyclohexyl methacrylate (meta).
Disclosed is an artificial marble obtained by curing a composition comprising acrylic syrup, aluminum hydroxide and a polymerization initiator having a 10-hour half-life temperature of less than 75 ° C. at low pressure for a long time. 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, it requires a long time of 2 hours or more for curing, and the productivity is low. Extremely bad. Therefore, in order to shorten the curing time and increase the productivity, these compositions are
If you try to cure it by heating it at a temperature of 00 ° C or higher, the decomposition temperature of the curing agent will be low, which will cause defects such as cracks and whitening in the molded product, resulting in loss of transparency and the depth unique to marble. I have no feeling.

On the other hand, in order to improve productivity, 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 is used. The production of a (meth) acrylic artificial marble by heating and pressing (shown) at a high temperature of 100 ° C. or higher has been conventionally studied. For example, JP-A-6-3130
Japanese Unexamined Patent Publication No. 19 discloses a method of manufacturing an artificial marble by heating and pressing an acrylic BMC in which aluminum hydroxide is mixed with an acrylic syrup containing methyl methacrylate as a main component at a high temperature of 115 ° C.

[0005]

However, when an acrylic artificial marble is produced by molding at a boiling point (100 ° C.) or higher of methyl methacrylate as described above, vapor of methyl methacrylate is generated in the mold. ,
The surface of the molded product is vulnerable to methylmethacrylate vapor, the gloss of the eroded portion is reduced, and unevenness in gloss easily occurs. Such a tendency becomes particularly remarkable when the curing temperature is increased to further increase the production rate.

Acrylic artificial marble as described in JP-A-6-313019 tends to be inferior in hot water resistance, and is used for bathtubs and the like which require particularly high hot water resistance. Is difficult. Furthermore, the acrylic SMC or BMC described in JP-A-6-313019 requires aging for a long time (24 hours or more) in order to increase the viscosity, and has a problem of low productivity. On the other hand, Japanese Unexamined Patent Publication (Kokai) No. 6-219800 discloses an artificial stone on a flat plate for a building material, which comprises 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. Has been done.
However, since the composition disclosed herein has a large amount of inorganic filler, it does not have a so-called marble-like deep and high-quality texture or a soft touch. 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 product having a complicated shape.

The object of the present invention is to be useful as a raw material for a (meth) acrylic artificial marble which has a molding appearance without uneven gloss, is excellent in moldability, and has good hot water resistance.
Acrylic premix, suitable for high temperature molding, excellent molding processability, good viscosity increase, especially useful as raw material for (meth) acrylic artificial marble (meth) acrylic SMC
Another object of the present invention is to provide a BMC and a method for producing a (meth) acrylic artificial marble which has high productivity and good molding 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 a (meth) acrylic resin composition containing a (meth) acrylate having an ester group having a specific structure causes uneven glossiness. We have found a (meth) acrylic premix that is useful as a raw material for acrylic artificial marble with excellent molding processability, excellent moldability, and good hot water resistance. By including a viscous agent, it has been found that the (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, and has high productivity. The 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 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 (meth) acrylate. Containing 100 parts by weight of the characteristic (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 higher. The present invention relates to a (meth) acrylic premix, which comprises 0.01 to 20 parts by weight of a curing agent (C), and contains the (meth) acrylic premix and a thickener. (Meth) acrylic SMC characterized by
It also relates to BMC, and relates to a method for producing a (meth) acrylic artificial marble, characterized in that the (meth) acrylic SMC or BMC is heated and pressed and cured 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) containing the same and a (meth) acrylic polymer. A (meth) acrylic resin composition (A) containing the polymer (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 higher). ).

A (meth) acrylate having an ester group having a cyclohexane ring, which is used as the component (a) constituting the (meth) acrylic resin composition (A) of the present invention, or a (meth) acrylic containing the same. 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 appearance without uneven gloss and excellent hot water resistance to the molded product. .

Specific examples of the (meth) acrylate having an ester group having a cyclohexane ring used as the component (a) include cyclohexyl (meth) acrylate, methylcyclohexyl (meth) acrylate and dimethylcyclohexyl ( (Meth) acrylate, trimethylcyclohexyl (meth) acrylate,
Tetramethylcyclohexyl (meth) acrylate, 2
-Cyclohexylethyl (meth) acrylate, 4-cyclohexylcyclohexyl (meth) acrylate and the like can be mentioned, but the invention is not limited thereto. Further, these may be used alone if necessary, or 2
You may use it in combination of 2 or more types. Particularly, cyclohexyl (meth) acrylate is preferable in terms of cost.

The (meth) acrylate having an ester group having a cyclohexane ring is preferably used in the range of 10 to 90% by weight in the (meth) acrylic resin composition (A) used in the present invention. If used within this range, the resulting molded article tends to have no uneven gloss,
Moreover, the hot water resistance of the molded product 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 5% by weight or less, and particularly preferably 80% by weight or less.

The other monomers used as the 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 and 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, fumaric acid ester, maleic acid, maleic acid ester, aromatic vinyl, vinyl acetate, (meth) acrylic acid amide, (meth) acrylonitrile, chloride Monofunctional monomers such as vinyl and maleic anhydride It is below.

These may be used alone or in combination of two or more, if necessary, but the (meth) acrylic monofunctional monomer tends to give a good appearance to the obtained molded article. And is preferable.

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

Further, it is preferable to contain a polyfunctional monomer as the component (a) because the molded product obtained 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, dimethylolethane di (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 (meth) acrylic acid and polyhydric alcohol Polyfunctional ester such as [polyethylene glycol, polypropylene glycol, pentaerythritol, dipentaerythritol, etc.], divinylbenzene, triaryl isocyanurate, aryl (meth) acrylate, etc. Monomers. These may be used alone or in combination of two or more, if necessary.

In particular, the use of neopentyl glycol dimethacrylate and / or 1,3-butylene glycol dimethacrylate as the polyfunctional monomer makes it possible to obtain a molded article having extremely excellent surface gloss and It is preferable because hot water 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, but in order to effectively obtain the above effects, 1 is added to the component (A) constituting the (meth) acrylic premix of the present invention. It is preferably used in the range of ˜50% by weight. The range is more preferably 3 to 40% by weight, and particularly preferably 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 to obtain the (meth) acrylic polymer (b), for example, various monomers exemplified as the above-mentioned component (a) can be applied as they are. it can. These various monomers may be used singly to obtain a homopolymer, or may be used in combination of two or more kinds to obtain a copolymer, and if necessary, may be added in a large amount. A cross-linked 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 according to need. However, the fluidity of the (meth) acrylic premix obtained and the mechanical properties of the molded product are obtained. Taking strength into consideration, its weight average molecular weight is in the range of 15,000 to 300,000, more preferably 25,000 to 250,000. The lower limit of the weight average molecular weight of the component (b) is 25,000.
0 or more is more preferable, 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) is
The amounts of the component (a) and the component (b) used may be appropriately selected and used without any particular limitation.

In consideration of workability of the (meth) acrylic premix of the present invention and physical properties such as mechanical strength when the (meth) acrylic premix is used as a raw material of 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 15% by weight or more, and 2
0% by weight or more is particularly preferable. The upper limit of the amount of component (a) used is more preferably 85% by weight or less, and 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 the (meth) acrylic premix is used as a raw material of a (meth) acrylic artificial marble are shown. Taking into account
The amount of the component (b) 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 component (b) used is more preferably 15% by weight or more, and particularly preferably 20% by weight or more. Also, (b)
The upper limit of the amount of the component used 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 composition 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 formed in the component (a), or the partially polymerized product to which the component (a) is further added, or the partially polymerized product (b) may be further added. ) Components may be added.

The inorganic filler (B) which is the component (B) which constitutes 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. In particular,
When the (meth) acrylic premix of the present invention is used as a molding material for artificial marble, the inorganic filler (B) is used.
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 with respect to 100 parts by weight of the (meth) acrylic resin composition (A). When the amount used is 1 part by weight or more, the resulting molded product tends to have good hot water resistance and a low linear shrinkage ratio. When the amount used is 500 parts by weight or less, the molded product tends to have a good marble-like deep texture. The lower limit of the amount of 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 component (B) used is more preferably 350 parts by weight or less, and particularly preferably 250 parts by weight or less.

The curing agent which is the component (C) constituting the (meth) acrylic premix of the present invention is 1 at 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 higher, the storage stability of the (meth) acrylic premix of the present invention tends to be good, and the molded article obtained can be 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 lower. The lower limit of the 10-hour half-life temperature of the radical polymerization initiator is more preferably 80 ° C or higher, and 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 higher include, for example, t-butyl peroxyisobutyrate (trade name Perbutyl IB, manufactured by NOF CORPORATION), 10 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
-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-tetramethylbutylper Oxy-3,3,5-trimethylhexanoate (Kyaku Akzo Co., Ltd., trade name KD-78, 10
Time half-life temperature = 86 ° C.), 1,1-bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane (produced by 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) 3,3,5-trimethylcyclohexane (NOF CORPORATION, trade name Perhexa 3M, 10-hour half-life temperature = 90 ° C.), 1,1
-Bis (t-butylperoxy) cyclohexane (Nippon Oil & Fats Co., Ltd., trade name Perhexa C, 10-hour half-life temperature = 91 ° C), 2,2-bis (4,4-di-t-butylperoxy) Cyclohexyl) propane (NOF Corporation)
Made, trade name Pertetra A, 10 hour half-life temperature = 95
C.), t-amylperoxy-3,3,5-trimethylhexanoate (Kayaester AN, trade name: Kayaester AN, 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., trade name Perhexyl I) ,
10-hour half-life temperature = 95 ° C.), diethylene glycol-bis (t-butylperoxycarbonate) (Kayalen O-50, 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 (Nippon Yushi Co., Ltd., 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 =
124-C), organic peroxides such as t-butyl hydroperoxide (produced by NOF CORPORATION, trade name Perbutyl H, 10-hour half-life temperature = 166.5C); 2,2-azobis (2,4) -Dimethylvaleronitrile) (Wako Pure Chemical Industries, Ltd., 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
-40, 10-hour half-life temperature = 88 ° C.) and the like.

In the present invention, the radical polymerization initiator having a 10-hour half-life temperature of 75 ° C. or higher 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.

Specific 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 (manufactured by Kayaku Akzo Co., Ltd., trade name Percadox 16, 10-hour half-life temperature = 44 ° C.), t-butylperoxy-2-ethylhexanoate (Nippon Yushi Co., Ltd.)
Made, brand name perbutyl O, 10 hour half-life temperature = 72
℃), benzoyl peroxide (Kayaku Akzo Co., Ltd.)
Manufactured by trade name Cadox B-CH50, 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.) and the like.

In the present invention, the amount of component (C) used is
It is in the range of 0.01 to 20 parts by weight with respect to 100 parts by weight of the (meth) acrylic resin composition (A). By setting the amount used to be 0.01 part by weight or more, (meth)
The curability of the acrylic premix tends to be sufficient, and when it 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 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 inorganic filler-containing resin particles (D) in addition to the components (A) to (C). By blending and molding the component (D) into the (meth) acrylic premix of the present invention, a granite-like artificial marble having a stone pattern can be obtained.

The amount of the inorganic filler-containing resin particles (D) used is not particularly limited, but is in the range of 0.1 to 200 parts by weight with respect to 100 parts by weight of the (meth) acrylic premix of the present invention. It is preferable. This is because when the amount of the inorganic filler-containing resin particles (D) used is 0.1 part by weight or more, a stone pattern with good design tends to be obtained, and when the amount is 200 parts by weight or less, 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) used is more preferably 1% by weight or more, and the upper limit is more preferably 100% by weight or less.

The resin forming the inorganic filler-containing resin particles (D) 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. it can.

The crosslinked (meth) acrylic resin has a high affinity with the (meth) acrylic resin composition (A), which is a constituent of the present invention, and a molded article having a beautiful molding appearance without uneven gloss can be obtained. Resins are preferred. The 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) is in the range of 1 to 500 parts by weight based on 100 parts by weight of the resin constituting the inorganic filler-containing resin particles. preferable. When the amount of the inorganic filler used is 1 part by weight or more, the heat resistance and the like of the obtained molded product are good, and when the amount of the inorganic filler used is 500 parts by weight or less, the molded product has a marble content. It tends to be possible to provide a good texture with a deep tone.

Specific examples of this inorganic filler include:
For example, inorganic fillers such as aluminum hydroxide, silica, fused silica, calcium carbonate, barium sulfate, titanium oxide, calcium phosphate, talc, clay and glass powder can be appropriately used if necessary. In particular, in the case of producing a granite-like artificial marble, it is preferable to use aluminum hydroxide, silica, fused silica, calcium carbonate, or glass powder as the inorganic filler because the effect is exhibited well.

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 polymerizing and curing by a hot pressing method, a casting method or the like is pulverized, A method of classifying with a sieve can be mentioned. For example, crushing (meth) acrylic artificial marble,
It is preferable to use the inorganic filler-containing resin particles obtained by classification. In the present invention, the inorganic filler-containing resin (D) may be used alone or in combination of two or more having different colors and particle sizes. The particle size of the resin particles (D) containing an inorganic filler 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 can be used as a (meth) acrylic SMC or BMC by further containing a thickener (E) as required.

The thickening agent (E) used in the case of the (meth) acrylic SMC or BMC is not particularly limited and may be appropriately selected according to need. For example, as described above. The inorganic filler-containing resin particles (D) can also be used as a thickener, and magnesium oxide powder, polymer powder or the like can be used.

In the present invention, the amount of the thickener (E) used is not particularly limited, but 100 weight of the (meth) acrylic resin composition (A) which is a constituent of the (meth) acrylic premix of the present invention. It is preferably in the range of 0.1 to 100 parts by weight with respect to 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, and when the amount used is 100 parts by weight or less, the acrylic prepolymer is 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.

Particularly, in order to improve the water resistance of the obtained molded product, it is preferable to use a polymer powder as the thickener (E). The polymer powder here may be either 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,
It is a polymer powder in which at least the surface layer portion is composed of a non-crosslinked polymer.

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 (meth) acrylic artificial marble of the present invention Considering the above points, a (meth) acrylic polymer is preferable.

Specific examples of the constituents of the polymer powder include, for example, alkyl (meth) acrylates 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, fumaric acid ester, maleic acid, maleic acid ester, aromatic vinyl,
Monofunctional monomers such as vinyl acetate, (meth) acrylic acid amide, (meth) acrylonitrile, vinyl chloride, 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-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) acrylates and polyhydric esters of (meth) acrylic acid with polyhydric alcohols such as polyhydric alcohols [polyethylene glycol, polypropylene glycol, pentaerythritol, dipentaerythritol, etc.], divinylbenzene, triaryl isocyanurate, aryl ( Polyfunctional monomers such as (meth) acrylate; and the like.

These may be polymerized singly or may be used in combination of two or more kinds, but the monomers constituting the (meth) acrylic premix of the present invention. Considering the affinity with the components, (meth) acrylic monomers are preferable.

In particular, the thickener (E) has a bulk density of 0.1 to 0.7 g / ml, an oil absorption amount of linseed oil of 60 to 200 ml / 100 g, and methyl methacrylate. When using a non-crosslinked polymer powder having a swelling degree of 16 times or more with respect to (meth) acrylic SMC or (meth) acrylic SMC excellent in handleability and productivity, the (meth) acrylic premix of the present invention is used. B
MC tends to be obtained, and a molded product having a good molding 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 during the production thereof is good, and the powdering at the time of adding and mixing the polymer powder to the (meth) acrylic premix is reduced, ( (Meth) acrylic SMC
This is also because the workability of manufacturing BMC tends to be good, and when the bulk density is 0.7 g / ml or less, a sufficient thickening effect can be obtained by using a small amount of polymer powder. (Meth) acrylic SMC or BM because it tends to be possible and the thickening time is short.
This is because the productivity of C is improved and the cost tends to be 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, particularly preferably 0.6 g / ml or less.

By adjusting the oil absorption amount of the polymer powder with respect to the 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. (Meta) because it tends to be possible and the thickening time is short.
This is because the productivity of acrylic SMC or BMC tends to be improved, and it tends to be advantageous in terms of cost as well.
When the amount is 100 g or less, the dispersibility of the polymer powder in the (meth) acrylic premix tends to be good, so that the (meth) acrylic SMC or B
It is preferable because the kneading property at the time of producing MC tends to be good. The lower limit of the oil absorption amount is more preferably 70 ml / 100 g or more, particularly preferably 80 ml / 100 g or more. The upper limit of this oil absorption is 180 mg / 100
g or less is more preferable, and 140 mg / 100 g or less is particularly preferable.

Further, by making the degree of swelling of the polymer powder with respect to methyl methacrylate 16 times or more,
The effect of thickening the (meth) acrylic premix tends to be sufficient. The degree of swelling 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 used.
, A sufficient thickening effect can be obtained in a short time, and the sharpness of the stone pattern is good, when used in the production of a granite-like artificial marble having 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 million or less.

The specific surface area of the polymer powder used as the thickener (E) in the present invention is not particularly limited, but it is preferably in the range of 1 to 100 m ² / g. This is because when the specific surface area of the polymer powder is 1 m ² / g or more, a sufficient thickening effect can be obtained by using a small amount of the polymer powder, and the thickening can be performed in a short time. Property is improved, and further, this polymer powder is included (meta)
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, and thus the kneading property at the time of producing the (meth) acrylic SMC or BMC tends to become 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 when the average particle size is 1 μm or more, the powderiness of the polymer powder tends to decrease, and the handleability of the polymer powder tends to be good. When the average particle size is 250 μm or less, This is because the appearance, especially gloss and surface smoothness tend to be good. The lower limit of the average particle diameter is more preferably 5 μm or more, and 1
0 μm or more is particularly preferable. The upper limit of the average particle diameter is more preferably 150 μm or less, 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 agglomerate, the absorption rate of the component (a) of the present invention is high and the viscosity increase tends to be extremely good.

In this case, the average particle size of the primary particles of the polymer powder is preferably 0.03 to 1 μm. This means that the average particle size of the primary particles is 0.
When the average particle size is 03 μm or more, the yield during the production of the polymer powder, which is a secondary aggregate, tends to be good, and 1
When it is less than or equal to μm, a sufficient thickening effect can be obtained with the use of a small amount of polymer powder, and the thickening time can be achieved in a short time. When a (meth) acrylic SMC or BMC containing this polymer powder as an agent (E) is used in the production of a granite-like artificial marble, the sharpness of the stone pattern is improved and the unevenness of the stone pattern is eliminated. This is because there is a tendency. More preferably,
The range of 0.07 to 0.7 μm is more preferable. The lower limit value of the average particle diameter of the primary particles is more preferably 0.07 μm or more, and the upper limit value 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 in which the polymers forming them have different chemical compositions, structures, molecular weights and the like. Further, it may be a polymer powder having a so-called core / shell structure. 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.

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

Further, the polymer powder which can be used as the thickener (E) in the present invention may contain an inorganic filler, but in order to further enhance the thickening effect, the inorganic powder is added. It is preferable not to contain a filler.

The method for producing the polymer powder is not particularly limited, and it can be obtained by a known method such as bulk polymerization, solution polymerization, suspension polymerization, emulsion polymerization and dispersion polymerization. Among these, 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.

If necessary, the (meth) acrylic premix of the present invention may further include reinforcing fibers such as glass fibers and carbon fibers, colorants, low-shrinking agents, polymerization inhibitors, internal release agents, etc. Various additives can be added.

The method of mixing the constituents to obtain 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. In addition, the (meth) acrylic premix of the present invention is thickened to give a (meth) acrylic SMC or B.
The various known mixing devices described above can also be used when obtaining MC. Particularly when a non-crosslinked polymer having the specific bulk density, oil absorption and swelling degree is used as a thickener,
Since the acrylic SMC or BMC of the present invention thickens to a level without stickiness in a short time and does not require aging, various components are uniformly mixed and simultaneously thickened and extruded,
A (meth) acrylic SMC or BMC can also be continuously produced by shaping into a predetermined shape.

The (meth) acrylic premix of the present invention can be heat-cured or redox-cured by a casting method as it is, or by adding the above-mentioned thickener (E) to the (meth) acrylic SMC. Alternatively, it can be heated and pressure-cured after being made into BMC, but in particular, from the viewpoint of productivity, a method of making it into a (meth) acrylic SMC or BMC and then heating and pressure-curing is preferable.

The method for producing an artificial marble of the present invention is a compression molding method in the case of producing a (meth) acrylic SMC or BMC and then heat-pressurizing the artificial marble to produce an artificial marble.
It can be manufactured by a known method such as an injection molding method, a transfer molding method, or an extrusion molding method. In this case, the heating temperature is not particularly limited, but a range of 100 to 150 ° C is preferable. This is because if the heating temperature is 100 ° C. or higher, it becomes possible to heat with steam, so the heating cost becomes lower,
Moreover, the curing time can be shortened, and the productivity tends to increase. On the other hand, when the heating temperature is 150 ° C. or lower, the linear shrinkage of the obtained molded product tends to be low. The lower limit of the heating temperature is more preferably 105 ° C or higher, particularly preferably 110 ° C or higher. The upper limit of the heating temperature is more preferably 145 ° C or lower, 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 heating temperature range.

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

[0070]

EXAMPLES The present invention will be specifically described below 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 just before the putty-like mass suddenly became soft 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: a value measured by the GPC method (in terms of polystyrene). Swelling degree: Polymer powder is put into a graduated cylinder of 100 ml, tapped several times to fill 5 ml, and then methyl methacrylate cooled to 10 ° C. or below is put so that the total amount becomes 100 ml, and the whole becomes uniform. So that it stirs quickly. 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). -Physical properties of molded products Hot water resistance: The molded plate was immersed in hot water at 98 ° C for 120 hours, and the color change (whiteness, color difference, yellowing degree) was compared with that of the plate before immersion.

(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 spray-dried at an inlet temperature / outlet temperature = 150 ° C./90° C. using an L-8 type spray dryer manufactured by Okawara Kakohki Co., Ltd., and the average particle diameter of the secondary aggregate particles was 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 amount for linseed oil is 100 ml / 100 g, the swelling degree for methyl methacrylate is 20 times or more, and the specific surface area is 51.
a m ² / g, weight average molecular weight was 600,000.

(2) Production Example of Polymer Powder (P-2) 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, 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 heated at the inlet temperature / using an L-8 type spray dryer manufactured by Okawara Kakoki Co., Ltd.
Outlet temperature = 150 ° C./90° C. Spray-dried in the same manner as for the polymer powder (P-1), 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 polymer powder (P-2) having a core / shell structure which is a cross-linked polymer was obtained. The bulk density of the obtained (P-2) is 0.
38 g / ml, the oil absorption for 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 part, and the monomer to be dropped was 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) Production Example of Polymethyl Methacrylate (B-1) in (Meth) acrylic Resin Composition 800 parts of pure water was placed in a reactor equipped with a cooling pipe, a thermometer, a stirrer and a nitrogen introducing pipe. , 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 Polycyclohexyl Methacrylate (B-2) The procedure of Production Example (4) was repeated except that cyclohexyl methacrylate was used instead of methyl methacrylate, and the average primary particle diameter was 150 μm. Polycyclohexyl methacrylate (B-2) was obtained. Obtained (B
-2) has a bulk density of 0.71 g / ml, a swelling degree of linseed oil of 45 ml / 100 g, a swelling degree of methylmethacrylate of 1.2, and a specific surface area of 0.07 m ² / g. The weight average molecular weight was 40,000. (6) Production Example of Resin Particles Containing Inorganic Filler A (meth) acrylic monomer consisting of 69% by weight of methyl methacrylate and 2% by weight of ethylene glycol dimethacrylate was added to the polymethylmethacrylate ( B-1) In 100 parts of a (meth) acrylic resin composition having 29 parts dissolved therein, t-butyl peroxybenzoate (manufactured by NOF CORPORATION), trade name Perbutyl Z, 10-hour half-life temperature = (104 ° C) 2.0 parts, 0.5 parts of zinc stearate as an internal release agent, and 0.25 parts of a white inorganic pigment or a black inorganic pigment as a colorant, and then aluminum hydroxide (Showa Denko) as an inorganic filler. (Manufactured by Co., Ltd., trade name Heidilite H-310) (200 parts) was added, and further 30 parts of the polymer powder (P-1) obtained in the above Production Example (1) was added as a thickener. And kneaded for 10 minutes leader was obtained (meth) acrylic BMC. Next, this (meth) acrylic BMC was filled in a 200 mm square flat mold and was heated and cured for 10 minutes under the conditions of a mold temperature of 130 ° C. and a pressure of 9.8 MPa to obtain a white or white film having a thickness of 10 mm. A black (meth) acrylic artificial marble was obtained. The obtained (meth) 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] Cyclohexyl methacrylate (Mitsubishi Rayon Co., Ltd., trade name Acryester C)
H) 25%, methyl methacrylate (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 ethylene glycol dimethacrylate (manufactured by Mitsubishi Rayon Co., Ltd., Acryester ED) 2% (meth) acrylic monomer (a) component and (b) component obtained in Production Example (1) Methyl methacrylate (B-
1) 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane (manufactured by NOF Corporation) in 100 parts of a (meth) acrylic resin composition having 25 parts dissolved therein , Trade name Perhexa 3M, 10-hour half-life temperature = 90 ° C.) 2.0 parts, and 0.5 parts of zinc stearate as an internal mold release agent, followed by 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. Obtained (meth) acrylic BMC
The sample had no stickiness immediately after kneading and had very 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 has no gloss unevenness and the gloss is extremely high.
The molding appearance was very good. In addition, 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.
I got C. The results of thickening are shown in Table 2. Next, Example 1
A (meth) acrylic artificial marble was obtained in the same manner as in (1).
Table 2 shows the evaluation results of the obtained molded products.

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.
I got C. The results of thickening are shown in Table 2. Next, Example 1
A (meth) acrylic artificial marble was obtained in the same manner as in (1).
Table 2 shows the evaluation results of the obtained molded products.

Example 4 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 2. 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 products.

Example 5 As polymer powder (P-3)
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 2. 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 products.

Example 6 A (meth) acrylic monomer (a) consisting 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 to (b) As a component, 100 parts of a (meth) acrylic resin composition in which 35 parts of polymethylmethacrylate (B-1) obtained in Production Example (1) was dissolved, and 1,1-bis (t-butylper) was used as a curing agent. Oxy) 3,3
After adding 2.0 parts of 5-trimethylcyclohexane (manufactured by NOF CORPORATION, trade name Perhexa 3M) and 0.5 part of zinc stearate as an internal release agent, aluminum hydroxide (Showa Denko ( 170 parts by trade name, Hijilite H-310, manufactured by K.K.) and the black and white inorganic filler-containing resin particles obtained in the above Production Example (6).
Parts, and further 25 parts of the polymer powder (P-1) obtained in the above Production Example (1) was added as a thickener, and 1 part was added with a kneader.
Kneaded for 0 minutes. The obtained (meth) acrylic BMC having a grain tone was not sticky even immediately after kneading, and was extremely easy to handle. Next, in the same manner as in Example 1, a granite-tone (meth) acrylic artificial marble molded product was obtained. Table 2 shows the evaluation results of the obtained molded products.

Comparative Example 1 48 parts of methyl methacrylate, 25 parts of neopentyl glycol dimethacrylate, 2 parts of ethylene glycol dimethacrylate were used as the (meth) acrylic resin composition, and the polymethyl methacrylate obtained in the above Production Example (1). (B-1) A mixture consisting of 25 parts, except that the curing agent is t-butyl peroxybenzoate (manufactured by NOF CORPORATION, trade name Perbutyl Z, 10-hour half-life temperature = 104 ° C.). A (meth) acrylic BMC was obtained in the same manner as in Example 1. The results of thickening are shown in Table 2. Next, 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 molded appearance. Further, 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. The results of thickening are shown in Table 1. Next, an acrylic artificial marble was obtained in the same manner as in Example 1. The obtained molded product had very uneven gloss and low gloss, and thus the molded appearance was very poor.

[Comparative Example 3] As a curing agent, 2,2'-azobis (2,4-dimethylvaleronitrile) (manufactured by Wako Pure Chemical Industries, Ltd., trade name V-65, 10-hour half-life temperature =
A molded product was obtained in the same manner as in Example 1 except that 10 parts (51 ° C.) was used and the other compositions were those shown in Table 1. The obtained molded product had extremely low transparency and had no depth feeling peculiar to marble.

Comparative Example 4 100 parts of (meth) acrylic resin composition consisting of 33 parts of cyclohexyl methacrylate, 33 parts of sec-butyl methacrylate and 34 parts of polycyclohexyl methacrylate (B-2) obtained in Production Example (5). In addition, benzoyl peroxide (manufactured by Kayaku Akzo Co., Ltd., trade name Cadox B-CH5 as a curing agent
(0, 10 hours half-life temperature = 72 ° C.) 3.0 parts, 0.5 parts of zinc stearate as an internal mold release agent, and then 200 parts of aluminum hydroxide as an inorganic filler, and kneading for 10 minutes with a kneader. A (meth) acrylic premix was obtained. This (meth) acrylic premix was aged at room temperature for 24 hours or longer, 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 the depth feeling peculiar to marble.

[0086]

[Table 1]

Evaluation result

[Table 2]

Thickening A of Premix A: Thickening immediately after kneading, a premix having good handleability without stickiness was obtained. B: After kneading, it took 24 hours or more to age at room temperature and increase the viscosity to the required viscosity. C: After kneading, it was aged at room temperature for 24 hours or more, but it did not thicken.

Depth feeling (transparency) of the molded product ◯: High transparency and a depth feeling peculiar to marble. Δ: The transparency is low and there is not much depth feeling peculiar to marble. X: The transparency is extremely low and there is no depth feeling peculiar to marble.

Uneven gloss of molded products ⊚: There is no gloss unevenness and the gloss is extremely high. ○ +: There is no gloss unevenness and the gloss is considerably high. ◯: High gloss with no uneven gloss. Δ: There is uneven gloss and the gloss is low. X: The gloss unevenness is severe and the gloss is extremely low.

Hot water resistance of molded products A: The color change was extremely small. ○ +: The color change was considerably small. ◯: Color change was small. X: The color change was large.

[0092]

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

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C08L 33/04 C08L 33/04 // C04B 111: 54 C04B 111: 54 (72) Inventor Yuichiro Kishimoto 4 Sunadabashi, Higashi-ku, Aichi Prefecture Nagoya City 1-60 No. Mitsubishi Rayon Co., Ltd. Product Development Research Laboratory (56) Reference JP-A-8-225705 (JP, A) JP-A-10-310458 (JP, A) JP-A-10-212393 (JP, A) ) JP-A-8-133807 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 33/04-33/16 C08F 2 / 44,265 / 06 C04B 26/06

Claims (6)

(57) [Claims] 1. A (meth) acrylate having an ester group having a cyclohexane ring, or a monomer mixture (a) containing the same and a (meth) acrylic polymer (b) are contained ( 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 higher. ) 0.01-20
A (meth) acrylic premix characterized by containing parts by weight. 2. A (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 inorganic filler-containing resin particles (D). 4. A (meth) acrylic SMC or BMC containing 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, characterized in that C or BMC is heated and pressure cured in the range of 100 to 150 ° C.