JPH11106596A - Composite resin composition for extrusion molding and production of molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composite resin composition capable of giving a molding desirably used as artificial marble and having excellent flame retardancy and to provide a process for producing a molding therefrom. SOLUTION: There are provided a composite resin composition containing 100 pts.wt. acrylic resin having a mean particle diameter of 160-2,000 μm, 300-600 pts.wt. aluminum hydroxide, 5-40 pts.wt. α,β-unsaturated carboxylic acid monomer having a boiling point of 102 deg.C or higher and a polymerization initiator and a process for producing a molding comprising extrusion-molding the above composition at a temperature of 140-199 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite resin composition for extrusion molding used for building materials, vanity tables, sink tops, bathtubs and the like, and a method for producing molded articles used in such applications. More specifically, extrusion molding, which is a molded article obtained by using an acrylic resin as a matrix and adding aluminum hydroxide as a filler to the molded article and exhibiting excellent flame retardancy. The present invention relates to a composite resin composition for use and a method for producing a molded article.

[0002]

2. Description of the Related Art Conventionally, so-called artificial marble is widely used in building materials, vanities, sink tops, bathtubs, etc. in order to enhance the appearance. Artificial marble is composed of a synthetic resin as a matrix, and a powder filler, in which at least one kind of aluminum hydroxide, magnesium hydroxide, calcium carbonate or silica is dispersed, to provide an aesthetic appearance similar to that of natural marble. And hardness.

[0003] JP-A-2-160648 discloses a composition for artificial marble for obtaining the above-mentioned artificial marble molded product. This composition comprises a polymerizable syrup containing methyl methacrylate as a main component and an average particle size of 5 to 80 μm.
An inorganic filler such as aluminum hydroxide powder, a polymethacrylate powder having an average particle size of 10 to 150 μm, and a polymerization initiator.

[0004] Since the artificial marble molding composition has the above-mentioned specific composition, the kneaded product of the composition exhibits a state of okara or rice cake. It is stated that molding can be performed by a method and that artificial marbles of various shapes can be easily obtained by polymerizing and curing the obtained molded article by heating.

[0005]

However, a molded article obtained by molding, polymerizing and curing the composition for artificial marble disclosed in Japanese Patent Application Laid-Open No. 2-160648 has transparency, hardness and hardness. Although it has excellent weather resistance, it has a disadvantage that it is easy to burn.

To increase the flame retardancy of the molded article, a method of increasing the compounding ratio of the inorganic filler can be considered. However, simply increasing the compounding ratio of the inorganic filler deteriorates the moldability, In addition, the desired artificial marble cannot be obtained by various molding methods such as extrusion molding.

An object of the present invention is not only to obtain molded articles excellent in appearance such as artificial marble of various shapes by extrusion molding, but also to obtain molded articles excellent in flame retardancy. It is an object of the present invention to provide a composite resin composition for extrusion molding, and a method for producing a molded article using the resin composition.

[0008]

The composite resin composition for extrusion molding according to the first aspect of the present invention has an average particle size of 160-2.
000 μm acrylic resin powder 100 parts by weight, aluminum hydroxide 300 to 600 parts by weight, boiling point 102
It is characterized by containing 5 to 40 parts by weight of an α, β unsaturated carboxylic acid monomer at a temperature of not less than ° C. and a polymerization initiator.

The invention described in claim 2 is the first invention.
A method for producing a molded article, characterized in that the resin composition for extrusion molding according to the invention described in (1) is subjected to extrusion molding at an extrusion molding temperature of 140 to 199 ° C.

Hereinafter, the present invention will be described in detail. (Acrylic Resin) In the present invention, the acrylic resin having the above specific particle size is used as the matrix resin constituting the molded article.

The acrylic resin is not particularly limited, and a thermoplastic acrylic resin having a single monomer composition or various different thermoplastic resins can be used. For example, an alkyl (meth) acrylate homopolymer or Copolymers can be mentioned, preferably, a thermoplastic methacrylic resin excellent in various properties such as transparency, hardness and weather resistance can be used.More preferably, inexpensive, methyl methacrylate alone can be used. A polymer is used.

[0012] Mean particle diameter (median diameter) D ₅₀ of the acrylic resin must be in the range of 160～2000Myuemu. If the average particle size is less than 160 μm, the cohesive force between the acrylic resins becomes too large, and the extrudability decreases. On the other hand, if it is 2000 μm or more, the extrusion moldability also decreases.

(Aluminum hydroxide) In the present invention, 300 to 600 parts by weight of aluminum hydroxide is used based on 100 parts by weight of the acrylic resin. If the amount is less than 300 parts by weight, the flame retardancy decreases, and
If the amount exceeds 0 parts by weight, the extrudability decreases.

[0014] Aluminum hydroxide, preferably, it is desirable that the average particle diameter (median diameter) D ₅₀ is in the range of 1 to 100 [mu] m. If it is smaller than 1 μm, the material viscosity in the extruder increases, and the extrudability may decrease. If it exceeds 100 μm, the surface properties of the extruded product may decrease.

If necessary, the surface of the aluminum hydroxide powder may be surface-treated using a silane coupling agent or a titanium coupling agent. Further, if necessary, in addition to aluminum hydroxide, other known inorganic fillers such as calcium carbonate, magnesium hydroxide, mica, calcium silicate, calcium aluminate hydrate, silica, and glass beads may be used in combination. You may.

(Α, β Unsaturated Carboxylic Acid Monomer) In the present invention, an α, β unsaturated carboxylic acid monomer having a boiling point of not less than 102 ° C. as described above is blended in the above-mentioned specific ratio.

The α, β unsaturated carboxylic acid monomer is not particularly limited as long as it has a boiling point of 102 ° C. or higher, and commercially available α, β unsaturated carboxylic acid, acrylic acid ester monomer or methacrylic acid ester monomer Can be used. When the boiling point is less than 102 ° C,
It volatilizes at the time of extrusion molding, and the surface properties of the obtained molded article are reduced.

Specific examples of the α, β unsaturated carboxylic acid monomer include the following. That is,
Examples of the α, β unsaturated carboxylic acid include methacrylic acid and acrylic acid.

Examples of the methacrylate monomer include ethyl methacrylate, n-butyl methacrylate,
Isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, alkyl methacrylate, tridecyl methacrylate,
Stearyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl methacrylate methyl chloride salt, diethylaminoethyl methacrylate, glycidyl methacrylate, Tetrahydrofurfuryl methacrylate, allyl methacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate,
Examples include 1,6-hexanediol dimethacrylate, trimethylolpropane trimethacrylate, and 2-ethoxyethyl methacrylate.

Examples of the acrylate monomer include acrylamide, allyl acrylate, isobutyl acrylate, 2- (5-ethyl-2-pyridyl) ethyl acrylate, 2-ethylhexyl acrylate, glycidyl acrylate, and acrylic acid 2 -Cyanoethyl, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, n-butyl acrylate, t-butyl acrylate, N
-Methylol acrylamide, glycidyl acrylate, β-hydroxyethyl acrylate, hydroxypropyl acrylate and the like.

The mixing ratio of the α, β unsaturated carboxylic acid monomer must be in the range of 5 to 40 parts by weight as described above. When the amount is less than 5 parts by weight, aluminum hydroxide cannot be sufficiently filled into the acrylic resin, and when the amount is more than 40 parts by weight, the material viscosity is too low, and the surface property of the molded article is low. I do.

(Polymerization initiator) As the above-mentioned polymerization initiator,
As long as the α, β unsaturated carboxylic acid monomer can be polymerized by heating, an appropriate polymerization initiator can be used.
Specifically, an appropriate polymerization initiator such as a ketone peroxide, a peroxyketal, a dialkyl peroxide, a diacyl peroxide, a peroxydiponate, and a peroxyester can be used.

Preferably, the polymerization initiator is 1
Those having a 0 hour half-life temperature of 60 ° C. or more are used. 1
If the 0-hour half-life temperature is lower than 60 ° C., the acrylic monomer may be excessively hardened at the time of extrusion molding, and the extrudability may be reduced.

More specifically, as the polymerization initiator, methyl acetoacetate peroxide, 1,1-
Bis (t-hexylperoxy) 3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) 3,3,5-trimethyl Cyclohexane, 1,
1-bis (t-butylperoxy) cyclohexane,
1,1-bis (t-butylperoxy) cyclododecane, 2,2-bis (t-butylperoxy) butane, n
-Butyl 4,4-bis (t-butylperoxy) valerate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, di-t-butyl peroxide, lauroyl peroxide, stearoyl Peroxide, 2,4-bichlorobenzoyl peroxide, octanoyl peroxide, benzoyl peroxide, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, 2,5-dimethyl2.5
-Bis (2-ethylhexanoylperoxy) hexane, 1-cyclohexyl 1-methylethylperoxy 2
-Ethylhexanoate, t-hexylperoxy 2-
Ethyl hexanoate, t-butyl peroxy 2-ethyl hexanoate, t-butyl peroxyisobutyrate, t-hexyl peroxyisopropyl monocarbonate, t-butyl peroxymaleic acid, t-butyl peroxy-3, 5,5-trimethylhexanoate, t
-Butyl peroxylaurate, 2,5-dimethyl 2,
5-bis (m-toluoylperoxy) hexane, t-
Butyl peroxyisopropyl monocarbonate, t-
Butyl peroxy 2-ethylhexyl monocarbonate, t-hexyl peroxy benzoate, 2,5-dimethyl 2,5-bis (benzoyl peroxy) hexane, t-butyl peroxy acetate, t-butyl peroxy m-toluoyl benzoate , T-butyl peroxybenzoate, 2,4,4-trimethylpentyl 2
-Hydroperoxide and the like.

More preferably, the 10-hour half-life temperature of the polymerization initiator is (extrusion temperature-70) ° C. <10-hour half-life temperature of polymerization initiator <
By using a polymerization initiator having a relationship of (extrusion temperature −10) ° C., the curing rate can be easily controlled.

The combination and the mixing ratio of the polymerization initiator and the α, β unsaturated carboxylic acid monomer are determined by a gel time tester (manufactured by Yasuda Seiki Seisakusho, part number: No. 153) under the same temperature conditions as the extrusion temperature. It is desirable that the measured gel time be adjusted to be 30 to 600 seconds. If the gel time is less than 30 seconds, the extrudability may decrease, and if it exceeds 600 seconds, the residual monomer in the extruded product may increase and the flame retardancy of the molded product may decrease.

(Flame Retardant) In the present invention, known flame retardants can be used as needed, as long as the object of the present invention is not impaired. Examples of flame retardants that can be used include, for example,
Brominated flame retardants such as decabromodiphenyl oxide, octabromodiphenyl oxide, hexabromocyclododecane, and brominated polystyrene; chlorinated flame retardants such as chlorinated paraffin and chlorinated polyethylene; phosphate esters, halogen-containing phosphate esters, and condensation Phosphate esters,
Examples include phosphorus-based flame retardants such as polyphosphate and red phosphorus; inorganic flame retardants such as antimony trioxide and guanidine; and reactive flame retardants such as tetrabromobisphenol A and tribromophenol.

(Other Additives) In the present invention,
If necessary, reinforcing materials such as glass fiber and carbon fiber,
Other fillers such as wood powder, marble powder, stone powder, and metal powder can be blended within a range that does not impair the purpose of the present invention.

(Molding) According to the second aspect of the present invention, a composite resin composition for extrusion molding containing the above components is used.
Extrude at an extrusion temperature of 199 ° C. In this case, at the time of molding, first, the composition containing each of the above-mentioned components is lightly stirred so as to be uniform, and charged into an extruder, and extrusion molding is performed at a molding temperature of 140 to 199 ° C. When the extrusion temperature is lower than 140 ° C., the aluminum hydroxide cannot be sufficiently kneaded, and the extrudability decreases. Conversely, if the extrusion temperature is higher than 199 ° C., the water of crystallization of aluminum hydroxide is desorbed, which affects the physical properties and surface properties of the obtained molded article.

The material is charged into the extruder by a method in which a powdery mixture obtained by mixing the materials in advance is charged into the extruder, and the powdery mixture excluding the α, β unsaturated carboxylic acid monomer is placed in a hopper of the extruder. An arbitrary method can be used, such as a method in which α and β unsaturated carboxylic acid monomers are charged and dropped directly on a kneading shaft of an extruder with a pump.

As the extruder, any of a single-screw extruder and a twin-screw extruder can be used. In order to improve the kneading property, it is desirable to use a twin-screw extruder.

In the method for producing a molded article according to the second aspect of the present invention, a molded article can be obtained by extrusion molding as described above. However, the shape of the molded article is not particularly limited, and the present invention is not limited to this. The molded body obtained by, for example, building materials,
It can be used for various purposes such as a vanity table, a sink top plate, and a bathtub.

(Function) The composite resin composition for extrusion molding according to the first aspect of the present invention has an average particle diameter of 160 to 2000 μm.
When kneading aluminum hydroxide as an inorganic filler with the acrylic resin powder of m, an α, β unsaturated carboxylic acid monomer having a boiling point of at least 102 ° C. is blended in the above-mentioned specific ratio. , Β-unsaturated carboxylic acid-based monomer and can be highly filled with aluminum hydroxide.

On the other hand, since aluminum hydroxide is desorbed from its water of crystallization at around 200 ° C., even if it is directly heated by fire, it loses heat of combustion. Flame retardancy is increased. Therefore, in the composite resin composition for extrusion molding according to the present invention, since the aluminum hydroxide is highly filled as described above, the flame retardancy of the obtained molded body is effectively improved.

The α, β-unsaturated carboxylic acid monomer for achieving a high filling of aluminum hydroxide contributes to the plasticization of the acrylic resin as described above. Cures at temperature, becomes polymer,
There is no decrease in hardness or transparency of the obtained molded article.

In the method for producing a molded article according to the second aspect, the composite resin composition for extrusion molding according to the first aspect is extruded at an extrusion temperature of 140 to 199 ° C. Gives a formed body. In this case, since the composite resin composition for extrusion molding contains the α, β unsaturated carboxylic acid-based monomer at the above-described specific ratio, the acrylic resin is plasticized, so that the aluminum hydroxide is high as described above. Filled in proportions. Therefore, the flame retardancy of the obtained molded body is enhanced, and the extrusion temperature of 140 to
Since extrusion molding is performed at 199 ° C, aluminum hydroxide filled in a high ratio is sufficiently kneaded, and water of crystallization is not released during molding. Therefore, a molded body having excellent physical properties and surface properties can be reliably formed by extrusion molding. And easily obtained.

[0037]

The present invention will be clarified by the following non-limiting examples. In the following, parts mean parts by weight unless otherwise specified.

(Example 1) 100 parts of methyl methacrylate polymer (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumipec, average particle size 300 μm) 100 parts Aluminum hydroxide (manufactured by Sumitomo Chemical Co., product number: CW308, average particle size 10 μm) 300 parts Cyclohexyl methacrylate (boiling point: 210 ° C) 20 parts Polymerization initiator (cumene hydroperoxide, 10 hour half-life temperature: 159 ° C) 0.1 part Formed at 180 ° C (150 × 3
mm).

(Example 2) 100 parts of methyl methacrylate polymer (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumipec, average particle size 300 μm) 100 parts Aluminum hydroxide (manufactured by Sumitomo Chemical Co., product number: CW308, average particle size 10 μm) 500 parts Cyclohexyl methacrylate (boiling point: 210 ° C) 20 parts Polymerization initiator (cumene hydroperoxide, 10 hour half-life temperature: 159 ° C) 0.1 part Formed at 180 ° C (150 × 3
mm).

Example 3 100 parts of methyl methacrylate polymer (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIPEC, average particle size 300 μm) 100 parts Aluminum hydroxide (manufactured by Sumitomo Chemical Co., product number: CW308, average particle size 10 μm) 500 parts N-butyl methacrylate (boiling point: 164 ° C.) 20 parts Polymerization initiator (t-butyl peroxybenzoate, 10-hour half-life temperature: 105 ° C.) 0.1 part Poured and extruded at 150 ° C. in sheet form (150 × 3
mm).

Comparative Example 1 Methyl methacrylate polymer (Sumitomo Chemical Co., Ltd., trade name: Sumipec, average particle size 300 μm) 100 parts Aluminum hydroxide (Sumitomo Chemical Co., product number: CW308, average particle size 10 μm) 0 parts Cyclohexyl methacrylate (boiling point: 210 ° C) 20 parts Polymerization initiator (cumene hydroperoxide, 10 hour half-life temperature: 159 ° C) 0.1 part Formed at 180 ° C (150 × 3
mm).

(Comparative Example 2) 100 parts of methyl methacrylate polymer (manufactured by Sumitomo Chemical Co., Ltd., trade name: SUMIPEC, average particle size 300 μm) 100 parts Aluminum hydroxide (manufactured by Sumitomo Chemical Co., product number: CW308, average particle size 10 μm) 200 parts Cyclohexyl methacrylate (boiling point: 210 ° C) 20 parts Polymerization initiator (cumene hydroperoxide, 10 hour half-life temperature: 159 ° C) 0.1 part Formed at 180 ° C (150 × 3
mm).

Comparative Example 3 Methyl Methacrylate Polymer (Sumitomo Chemical Co., Ltd., trade name: SUMIPEC, average particle size 300 μm) 100 parts Aluminum hydroxide (Sumitomo Chemical Co., product number: CW308, average particle size 10 μm) 650 parts Cyclohexyl methacrylate (boiling point: 210 ° C) 20 parts Polymerization initiator (cumene hydroperoxide, 10 hour half-life temperature: 159 ° C) 0.1 part Formed at 180 ° C (150 × 3
mm).

(Comparative Example 4) 100 parts of methyl methacrylate polymer (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumipec, average particle size 300 μm) 100 parts Aluminum hydroxide (manufactured by Sumitomo Chemical Co., product number: CW308, average particle size 10 μm) 300 parts The above mixture was stirred so as to be uniform, and was charged from a hopper of an extruder.
mm).

(Comparative Example 5) 100 parts of methyl methacrylate polymer (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumipec, average particle size 300 μm) 100 parts Aluminum hydroxide (manufactured by Sumitomo Chemical Co., product number: CW308, average particle size 10 μm) 500 parts Cyclohexyl methacrylate (boiling point 210 ° C.) 20 parts Polymerization initiator (cumene hydroperoxide, 10-hour half-life temperature 159 ° C.) 0.05 part Sheet-shaped (150 × 3
mm).

(Comparative Example 6) 100 parts of methyl methacrylate polymer (manufactured by Sumitomo Chemical Co., Ltd., trade name: Sumipec, average particle size 300 μm) 100 parts Aluminum hydroxide (manufactured by Sumitomo Chemical Co., product number: CW308, average particle size 10 μm) 500 parts N-Butyl methacrylate (boiling point: 164 ° C) 20 parts Polymerization initiator (t-butyl peroxybenzoate, 10-hour half-life temperature: 105 ° C) 0.1 part The above is uniformly stirred and charged from the hopper of the extruder. And extruded into a sheet (150 × 3
mm).

Comparative Example 7 Methyl methacrylate polymer (manufactured by Sekisui Chemical Co., Ltd., trade name: Techpolymer MB-20, average particle size: 20 μm) 100 parts Aluminum hydroxide (manufactured by Sumitomo Chemical Co., product number: CW308) Average particle size 10 μm) 300 parts Cyclohexyl methacrylate (boiling point 210 ° C.) 20 parts Polymerization initiator (cumene hydroperoxide, 10-hour half-life temperature 159 ° C.) 0.1 part Into a sheet (150 × 3) at an extrusion molding temperature of 180 ° C.
mm).

(Evaluation of Examples and Comparative Examples) With respect to the sheet-like extruded products obtained in Examples and Comparative Examples, extrudability, surface properties and flame retardancy were evaluated in the following manner.

Extrusion moldability / surface property: At the time of the above extrusion molding, whether or not extrusion was possible and whether or not the surface property was good were visually evaluated. The evaluation criteria are as follows. A: Extrusion molding was possible, and the surface properties of the obtained molded article were good. B: Although extrusion molding was possible, air bubbles were observed on the surface of the obtained molded body, and kneading defects were observed. C: Extrusion molding could not be performed.

Flame retardancy: The flame retardancy of the obtained molded article
Flame retardancy was evaluated according to IS K7201 “Combustion test method for polymer materials by oxygen index method”. The higher the oxygen index obtained in this evaluation, the higher the flame retardancy. The results are shown in Table 1 below.

[0051]

[Table 1]

In Table 1, the polymerization initiator is cumene hydroperoxide as the polymerization initiator, and the polymerization initiator is t-butyl peroxybenzoate.
In addition, before and after the mixing ratio in the column of α, β unsaturated carboxylic acid monomer, respectively, indicate cyclohexyl methacrylate, and indicates n-butyl methacrylate.

As is clear from Table 1, in Comparative Example 1,
Since aluminum hydroxide was not used, the obtained molded article had a low flame retardancy of 18 as the oxygen index. Also in Comparative Example 2, the use ratio of aluminum hydroxide was 200%.
Oxygen index was 3 in the flame retardancy evaluation
It was as low as 0.

On the other hand, in Comparative Example 3, the compounding ratio of aluminum hydroxide was too large at 650 parts, or extrusion molding was possible, but kneading was insufficient, and it could be used for flame retardancy evaluation. No sample could be obtained.

In Comparative Example 4, since no α, β unsaturated carboxylic acid monomer was used, extrusion molding was impossible when the mixing ratio of aluminum hydroxide was 300 parts. In Comparative Example 5, the 10-hour half-life temperature was 159
C. Cumene hydroperoxide was used, but the extrusion molding temperature was too high as 210 ° C., but extrusion molding was possible, but the surface properties of the obtained molded product were not good, and the flame retardancy was evaluated. A usable sample could not be obtained.

In Comparative Example 6, t-butyl peroxybenzoate having a 10-hour half-life temperature of 105 ° C. was used as a polymerization initiator. However, the extrusion molding temperature was too low at 130 ° C. there were. In Comparative Example 7, extrusion molding was impossible, probably because the particle size of the acrylic resin was too small and the cohesive force between the resins was too large.

In contrast, in Examples 1 to 3, the composite resin composition for extrusion molding prepared according to the present invention was used.
Because the molding temperature at the time of extrusion was 180 ° C. or 150 ° C., it was possible to obtain a molded article which was not only extrudable but also excellent in surface properties. In addition, regarding the flame retardancy of the obtained molded body, the oxygen index was 53 or 9
As high as 5 or more, it can be seen that the flame retardancy is dramatically improved.

[0058]

According to the composite resin composition for extrusion molding according to the first aspect of the present invention, an α, β unsaturated carboxylic acid having a boiling point of at least 102 ° C. per 100 parts by weight of an acrylic resin having an average particle size of 1602000 μm. By blending 5 to 40 parts by weight of the system monomer, the acrylic resin is easily plasticized at the time of extrusion molding.
Despite being compounded in a high ratio of up to 600 parts by weight, a molded article having excellent surface properties can be reliably obtained by extrusion molding. Moreover, since the α, β unsaturated carboxylic acid monomer is cured by the polymerization initiator depending on the temperature during extrusion molding, a molded article having sufficient hardness and shape retention can be obtained.

Further, since a molded article containing aluminum hydroxide in a high proportion as described above can be obtained, the molded article exhibits sufficient flame retardancy. Therefore, the composite resin composition for extrusion molding according to the invention of claim 1 is used, and for example, the extrusion molding temperature is set to 1 as described in claim 2.
By extruding in the temperature range of 40 to 199 ° C,
A molded article that is not only suitable for use as artificial marble but also has excellent flame retardancy can be provided.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29K 505: 02 B29L 9:00

Claims (2)

[Claims] 1. An acrylic resin powder having an average particle size of 160 to 2000 μm, 100 parts by weight of aluminum hydroxide, 300 to 600 parts by weight of aluminum hydroxide, and an α, β unsaturated carboxylic acid monomer having a boiling point of 102 ° C. or more 5 to 40. A composite resin composition for extrusion molding comprising: parts by weight; and a polymerization initiator. 2. A method for producing a molded article, comprising extruding the composite resin composition for extrusion molding according to claim 1 at an extrusion molding temperature of 140 to 199 ° C.