JP2009154440A - Three-layer extruded moldings - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide foamed polystyrene extruded moldings with excellent cut-through or cutting properties without burr generation during cut-through or cutting operation. <P>SOLUTION: These three-layer extruded moldings are formed of co-extruded three layers such as a foamed polystyrene-based base layer (A), an acrylstyrene-based intermediate layer (B) and an acrylonitrile-styrene-based surface layer (C). The base layer (A) includes a polystyrene, a styrene-based elastomer and a polyolefin-based resin, and has a foam expansion ratio which is 1.1-to 5.0-fold. The intermediate layer (B) is formed of an acrylstyrene-based copolymer resin having at least, an acrylate unit and a styrene unit. The acrylonitrile-styrene-based surface layer (C) is formed of an acrylonitrile-styrene-based copolymer resin having at least, an acrylonitrile unit and a styrene unit. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a three-layer extrusion molded article in which a surface layer is formed on a polystyrene base layer via an acrylic styrene intermediate layer.

  Polystyrene resins are used for various applications because they are excellent in transparency and molding processability, and are inexpensive. For example, extruded polystyrene foam is highly processable and lightweight. Widely used in the field. On the other hand, polystyrene resins, on the other hand, have insufficient surface hardness, surface glossiness, weather resistance, etc., and are therefore often used with a polymethyl methacrylate (PMMA) resin layer provided on the surface. In this case, an intermediate layer for adhering both layers is provided between the base layer of polystyrene resin and the PMMA resin layer. For example, in Patent Document 1, a base layer of polystyrene resin foam, an intermediate layer made of methyl methacrylate styrene copolymer resin (MS resin), and a surface layer of PMMA resin are formed by three-layer coextrusion molding. The resulting building interior and exterior materials have been proposed.

  Now, in order to prevent the exhaustion of petroleum resources, the reuse of various plastic products is being studied. In particular, polystyrene has recently become difficult to obtain and its price is rising, and therefore its reuse is desired. In fact, Patent Document 2 proposes a roof rail using recycled expanded polystyrene. Yes.

Moreover, as a synthetic resin composition for woodwork using polystyrene, Patent Document 3 proposes a combination of a polyolefin resin having a melt flow rate (MFR) of 0.3 to 30 and polystyrene having an MFR of 0 to 30. Has been.
Japanese Patent No. 3905642 JP 2004-218307 A Japanese Patent Laid-Open No. 10-101812

  However, the conventionally known polystyrene molded article has a problem that the cutting property or the cutting property is poor, for example, there is a defect that burrs are generated when it is cut using an electric saw or the like. Or there exists a tendency for the machinability to get worse. For example, even in the three-layer extrusion molded body of Patent Document 1 and the tile pier of Patent Document 2, such cutability or machinability has not been improved, and further, the resin composition for woodworking of Patent Document 3 was used. The extrudate does not improve cutting performance, etc., and it must be cut or cut carefully. Especially in the field of architecture, it may cause problems such as poor workability or use in an invisible place. It is subject to restrictions such as having to do. In addition, the three-layer extrusion-molded body of Patent Document 1 also has a drawback in that the surface PMMA resin layer is easily cracked during cutting or cutting.

Accordingly, an object of the present invention is to provide an extruded product of expanded polystyrene that does not generate burrs during cutting or cutting and has excellent cutting properties or cutting properties (hereinafter referred to as cutting workability).
Another object of the present invention is to provide a three-layer extrusion molded article in which properties such as weather resistance of polystyrene are improved, and further, excellent cutting workability is exhibited even when recycled polystyrene is used.

According to the present invention, in the three-layer extrusion molded body formed by co-extrusion of the three layers of the expanded polystyrene base layer (A), the acrylic styrene intermediate layer (B), and the acrylonitrile styrene surface layer (C). ,
The expanded polystyrene base layer (A) is
(A1) 100 parts by weight of polystyrene having a melt flow rate (MFR) of 0.1 to 20 g / 10 min,
(A2) Styrenic elastomer 5 to 30 parts by weight,
(A3) 2.5 to 30 parts by weight of polyolefin resin,
And has a foaming ratio of 1.1 to 5.0 times,
The acrylic styrene intermediate layer (B) is formed from an acrylic styrene copolymer resin having at least an acrylate unit and a styrene unit,
The acrylonitrile styrene surface layer (C) is formed from an acrylonitrile styrene copolymer resin having at least an acrylonitrile unit and a styrene unit,
A three-layer extrudate is provided.

In the present invention, preferred embodiments are as follows.
(1) The polyolefin resin (A3) has an MFR in the range of 0.1 to 20 g / 10 min and in the range of 0.1 to 10 times the MFR of the polystyrene.
(2) 50% by weight or more of the polyolefin resin (A3) is polyethylene.
(3) The polyolefin resin (A3) contains polyethylene (PE) and polypropylene in a weight ratio of PE / PP = 75/25 to 25/75.
(4) The acrylic styrene copolymer resin contains 50% by weight or more of acrylic units and 20% by weight or more of styrene units.
(5) The acrylic styrene copolymer resin is a methyl methacrylate / styrene copolymer resin.
(6) The acrylic styrene-based intermediate layer (B) contains an acrylic elastomer in an amount of 2.5 to 25 parts by weight per 100 parts by weight of the acrylic styrene-based copolymer resin.
(7) The acrylonitrile styrene copolymer resin is a copolymer resin having an acrylate unit, a styrene unit and an acrylonitrile unit or a copolymer resin having a silicone unit, an acrylate unit, an acrylonitrile unit and a styrene unit.
(8) The acrylic styrene-based intermediate layer (B) contains a colorant in an amount of 30 parts by weight or less per 100 parts by weight of the acrylic styrene-based copolymer resin, and the acrylonitrile styrene-based surface layer (C) is A colorant is contained in an amount of 20 parts by weight or less per 100 parts by weight of the acrylonitrile styrene copolymer resin.
(9) The base layer (A) has a thickness of 3 to 50 mm, the intermediate layer (B) has a thickness of 0.1 to 1.0 mm, and the surface layer (C) has a thickness of 0.5 to 2 It has a thickness of 0.0 mm.
(10) Use as an architectural interior material or exterior material.

  The three-layer extrusion molded product of the present invention, which uses a molded product of expanded polystyrene as a base layer, is excellent in lightness, high in surface hardness, excellent in killing resistance and chemical resistance. As is clear from the examples, it has excellent machinability, and even when it is cut using an electric saw, it hardly generates burrs, which makes it extremely useful as an interior / exterior material for buildings. Useful. Further, the machinability as described above is not impaired even when a recycled product is used as the polystyrene for forming the base layer, and thus is excellent in terms of resource saving and economical efficiency. Furthermore, the adhesiveness of each layer is also excellent, and inconveniences such as delamination are effectively prevented.

  Moreover, what mix | blended the coloring agent with the intermediate | middle layer (B) and the surface layer (C) is excellent also in the concealment property of a base layer (A). For example, when recycled polystyrene is used, the base layer (A) often has a dark color. In such a case, a colorant is added to the intermediate layer (B) and the surface layer (C). Then, the color of the lower base layer (A) can be effectively concealed. For example, even when a white colorant is used as the colorant, the dark color of the base layer (A) can be concealed, so that restrictions due to the use of recycled products can be effectively avoided.

  The three-layer extruded product of the present invention is formed by co-extrusion of three layers of a foamed polystyrene-based base layer (A), an acrylic styrene-based intermediate layer (B), and an acrylonitrile-styrene-based surface layer (C). Yes, each layer will be described below.

<Expanded polystyrene base layer (A)>
The expanded polystyrene base layer (A) is formed by co-extruding a resin composition containing polystyrene (A1) as a main component with the other layers (B) and (C). Foamed at a magnification of 1 to 5.0 times. That is, by foaming at such a magnification, lightness is ensured and at the same time, cutting workability is improved.

  In addition to the main component polystyrene (A1), the above resin composition is blended with a styrene elastomer (A2) and a polyolefin resin (A3), and further with a foaming agent (A4).

Polystyrene (A1):
Polystyrene is a base material component that forms the base layer (A), and mechanical properties such as strength can be secured by using polystyrene as a base material.

  In the present invention, the melt flow rate (MFR: JISK 7210, 200 ° C., 5 kg) of such polystyrene needs to be in the range of 0.1 to 20 g / 10 min, particularly 1.0 to 10 g / 10 min. When the MFR is larger than the above range, molding becomes difficult, and when the MFR is smaller than the above range, properties such as strength are deteriorated and foaming becomes difficult.

  Moreover, as long as it has MFR as mentioned above, recycled polystyrene can also be used conveniently. Rather, even when such recycled polystyrene is used, it can be said that the greatest advantage of the present invention is that deterioration of physical properties can be avoided and excellent characteristics such as cutting workability can be obtained.

Styrene elastomer (A2):
The styrene-based elastomer is a component that contributes to the improvement of impact resistance, but improves the compatibilization between the polyolefin-based resin described later and the polystyrene (A1), which is a base material component, and the acrylic-styrene-based intermediate layer (described later) It is also a component for improving the adhesiveness with B). That is, when other rubber components (for example, acrylic rubber) other than styrene elastomers are used, the compatibility between polystyrene and polyolefin resins such as polyethylene or polypropylene is extremely low, resulting in poor dispersion and the like. In addition, the adhesive properties with the styrene-acrylic intermediate layer (B) are impaired, and peeling between the base layer (A) and the intermediate layer (B) is likely to occur.

  Such styrenic elastomers are block copolymers with polystyrene phases in both terminal phases, and have a polybutadiene or polyisoprene layer as an intermediate layer. At room temperature, they exhibit excellent elasticity like vulcanized rubber and high temperatures. It can be easily processed with a general plastic molding machine. Such styrene elastomers include butadiene-styrene copolymer (SBS), isoprene-styrene copolymer (SIS), styrene-ethylene-butadiene-styrene copolymer (SEBS), etc., and improved impact resistance. SEBS is most suitable from the viewpoint of great effect and resin modification. Those having a polybutadiene content generally in the range of 5 to 80% by weight, particularly 50 to 70% by weight, are readily available.

  This styrenic elastomer is used in an amount of 5 to 30 parts by weight, particularly 10 to 20 parts by weight, per 100 parts by weight of polystyrene (A1). If this amount is less than the above range, poor dispersion of the polyolefin resin, which will be described later, is caused, and not only the overall properties of the three-layer extrusion molded product are lowered, but the moldability of the resin composition is also lowered. End up. Further, use in a larger amount than the above range results in a decrease in rigidity.

Polyolefin resin (A3):
Polyolefin resin is a component that imparts impact resistance and further improves cutting workability, and is used in an amount of 2.5 to 30 parts by weight, particularly 8 to 20 parts by weight, per 100 parts by weight of polystyrene (A1). Is done. If this amount is less than the above range, not only the impact resistance will be lowered, but also the machinability will be lowered. For example, when the molded body is cut with an electric saw, many burrs will be generated. It becomes.

  The MFR (JIS K 7210, 230 ° C., 2.16 kg) of such a polyolefin-based resin may be in the range of 0.1 to 20 g / 10 min, particularly 1.0 to 10 g / 10 min, similar to the above polystyrene. Furthermore, it is preferable that it is in the range of 0.1 to 10 times the MFR of the polystyrene. That is, if the two MFRs are separated from each other, the moldability may be deteriorated.

  In the present invention, various polyolefin-based resins can be used as the polyolefin-based resin. In particular, from the viewpoint of enhancing flexibility, imparting impact resistance, and greatly improving cutting workability, polyethylene, For example, high density polyethylene (HDPE), medium density polyethylene (MDPE), low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and the like are suitable, and at least 25% by weight or more of such polyolefin resin is polyethylene. Is preferred.

  In the present invention, it is most preferable to use polypropylene together with the above polyethylene. That is, the combined use of polypropylene provides rigidity, and as a result, rigidity and flexibility are imparted with an appropriate balance, and not only the strength such as bending strength is increased, but also the machinability is further improved. For example, using polyethylene (PE) and polypropylene (PP) at a weight ratio of PE / PP = 75/25 to 25/75 as the polyolefin-based resin described above ensures excellent machinability and the like. Best on. In this case, if polypropylene is used in a larger amount than the above range, it may be difficult to sufficiently foam.

  As the polypropylene, any one having the above-mentioned MFR can be used with either an isotactic structure or a syndiotactic structure. Furthermore, in addition to homopolypropylene, random copolymer polypropylene can be used. Alternatively, block copolymerized polypropylene can be used. Examples of the comonomer in these copolymers include olefins other than propylene, such as ethylene and 1-butene, or a combination of two or more. In the present invention, homopolypropylene is most preferable particularly from the viewpoint of rigidity.

Foaming agent (A4):
There are various types of foaming agents, but in the present invention, chemical foaming agents are used in particular. That is, physical foaming using gas impregnation and expansion requires a special facility for foaming, which is disadvantageous in terms of economy and productivity.

  Examples of the foaming agent used in the present invention include, but are not limited to, inorganic foaming agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, and ammonium nitrite; N, N′-dimethyl- Nitroso compounds such as N, N'-dinitroso / terephthalamide, N, N'-dinitroso / pentamethylene / tetramine; azodicarbonamide, azodicarboxamide, azobisisobutyronitrile, azocyclohexylnitrile, azodiaminobenzene, barium Azo compounds such as azodicarboxylate; sulfonyl hydrazide compounds such as benzenesulfonyl hydrazide, toluenesulfonyl hydrazide, P, P′-oxybis (benzenesulfonyl hydrazide), diphenylsulfone-3,3′-disulfonyl hydrazide; calcium Azide compounds such as zido, 4,4′-diphenyldisulfonyl azide, p-toluenesulfonyl azide, etc. can be mentioned, and these can be used alone or in combination of two or more. It can also be used.

  Such a foaming agent is used in such an amount that the foaming ratio is 1.1 to 5.0 times depending on the types, physical properties and blending amounts of the components (A1) to (A3) to be used. Is used in an amount of 0.1 to 3 parts by weight per 100 parts by weight of polystyrene (A1). If the amount is smaller than this, foaming becomes insufficient, and the molded extruded product is unsatisfactory in terms of lightness and workability. Further, if it is used in a larger amount than the above range, foaming becomes excessive and the rigidity of the extruded molded product becomes unsatisfactory, and particularly, a large amount of burrs are generated when it is cut with a saw.

Other additives:
In the present invention, the base layer-forming resin composition contains various additives known per se in an amount as long as the properties such as rigidity and impact resistance of the molded extruded product are not impaired. Can be blended.

  For example, a foaming aid can be blended in order to lower the decomposition temperature of the foaming agent, accelerate the decomposition, and make the bubbles uniform. Examples of such foaming aids include organic acids such as salicylic acid, phthalic acid and stearic acid; urea and derivatives thereof. Moreover, inorganic fine powders such as talc, various clays, calcium silicate, magnesium silicate and the like can be blended for the purpose of adjusting bubbles. In addition, for the purpose of improving processability and moldability, a lubricant such as a fatty acid metal soap such as barium stearate or magnesium stearate, a fatty acid amide, a polyethylene wax, or a microcrystalline wax may be blended. Furthermore, wood powder can be blended as appropriate for weight reduction. As such wood powder, those having a particle size of 100 mesh size or less (150 μm or less) are used. For example, any wood powder such as conifer, hardwood, lauan, etc. is used, and sawdust produced as a by-product during sawing. Sawdust and the like can also be powdered by ball milling or the like. In addition to these additives, fillers, colorants, heat stabilizers, weathering stabilizers, antioxidants, anti-aging agents, light stabilizers, UV absorbers, antistatic agents, etc., as necessary. As needed, it can mix | blend suitably.

  The thickness of the base layer (A) formed by coextruding the resin composition described above together with the intermediate layer (B) and the surface layer (C) and foaming is not particularly limited, depending on the application. Although it can be set to an appropriate thickness, it is generally preferable that the thickness is in the range of 3 to 50 mm from the viewpoint of making the most of the characteristics of polystyrene and ensuring weight reduction by foaming and improvement of workability.

<Acrylic styrene-based intermediate layer (B)>
The acrylic styrene-based intermediate layer (B) is a layer that is provided between the above-mentioned expanded polystyrene-based base layer (A) and an acrylonitrile styrene-based surface layer (C) described later, and adheres both layers. And an acrylic styrene copolymer resin having an acrylate unit and a styrene unit.

  As the acrylic styrene copolymer resin as described above, a copolymer of (meth) acrylate and a styrene monomer (such as styrene or α-methylstyrene) is preferable, but the base layer (A) and the surface layer (C From the standpoint of having good adhesiveness to acrylic), an acrylic styrene copolymer resin containing 50% by weight or more of acrylate units and 20% by weight or more of styrene units (particularly styrene units) is suitable. In particular, a methyl methacrylate / styrene copolymer resin (MS resin) containing 50 to 80% by weight of methyl methacrylate (MMA) and 20 to 50% by weight of styrene is optimal.

The acrylic styrene copolymer resin as described above preferably has a Mooney viscosity (MVR; ISO 1133, 220 ° C., 10 kg) in the range of ^{3 to} 10 cm ³ g / 10 min from the viewpoint of extrusion moldability. .

  The thickness of the intermediate layer (B) formed from the acrylic styrene copolymer resin is generally preferably in the range of 0.1 to 1.0 mm. That is, if the thickness is too thin, the adhesion between the base layer (A) and the surface layer (C) becomes unsatisfactory, and the surface layer (C) is likely to peel off. Moreover, even if it is formed thicker than necessary, the adhesive strength between the base layer (A) and the surface layer (C) does not improve beyond a certain value, but rather the physical properties of the base layer (A) containing polystyrene as a main component. This is because there is a risk of lowering the cutting workability.

  Moreover, in this invention, a coloring agent can also be mix | blended with this intermediate | middle layer (B), and the concealment of the color of a base layer (A) can be aimed at by mixing | blending a coloring agent. That is, when recycled polystyrene is used to form the base layer (A) described above, the base layer (A) may exhibit a dark color. In such a case, the color of the base layer (A) can be concealed and any color can be expressed by blending the colorant, and the commercial value of the molded product can be increased. As such a colorant, generally, an inorganic pigment exhibiting white to black or a color is used depending on the color to be developed.

  The amount of the colorant used should be an amount that does not impair the adhesiveness of the intermediate layer (B), and generally 30 parts by weight or less per 100 parts by weight of the acrylic styrene copolymer resin. It is good to do.

  The acrylic styrene intermediate layer (B) is blended with an acrylic elastomer in an amount of 2.5 to 25 parts by weight, particularly 8 to 20 parts by weight per 100 parts by weight of the acrylic styrene copolymer resin. May be. By blending the acrylic elastomer in such an amount, particularly the adhesion with the surface layer (C) is improved, and further, the flexibility of the intermediate layer (B) is enhanced, and the machinability of the molded body is further improved. Can be improved.

  As the acrylic elastomer as described above, those known per se are used. For example, an elastomer containing an acrylic ester having an alkyl group having 1 to 8 carbon atoms as an acrylic unit, for example, acrylic ester / chloromethylstyrene. Typical examples include copolymer elastomers, acrylate / allyl glycidyl ether copolymer elastomers, acrylate / glycidyl methacrylate copolymer elastomers, and acrylate / chloroethyl vinyl ether copolymer elastomers. Is preferably contained in an amount of 50% by weight or more.

<Acrylonitrile styrene surface layer (C)>
In the extruded product of the present invention, the acrylonitrile styrene surface layer (C) formed on the surface is formed from an acrylonitrile styrene copolymer resin having acrylonitrile units and styrene units, and such a surface layer is provided. Thereby, without damaging the characteristic of the base layer (A) formed from polystyrene, killing resistance and weather resistance can be improved, and chemical resistance can also be improved.

  As the acrylonitrile styrene copolymer resin as described above, acrylonitrile / acryl rubber / styrene copolymer resin (ASA resin) obtained by copolymerizing acrylic rubber and acrylonitrile / styrene is preferable. A copolymer resin having a silicone unit (SiO unit) in addition to an acrylonitrile unit and a styrene unit, for example, acrylonitrile / silicone-modified acrylic rubber / styrene copolymer resin (SAS resin) can also be suitably used. Furthermore, acrylonitrile / EPDM / styrene copolymer resin (AES resin) and acrylonitrile / butadiene / styrene copolymer resin (ABS resin) can also be suitably used as similar resins having high adhesion to acrylic resin.

  The copolymerization ratio of each component in the ASA resin or the SAS resin may be an appropriate amount ratio depending on the target characteristics and the like. For example, when the impact resistance is to be increased, the amount of the rubber component You should increase more.

The acrylonitrile styrene copolymer resin as described above preferably has an MVR (ISO 1133, 220 ° C., 10 kg) in the range of 1 to 20 cm ³ g / 10 min from the viewpoint of extrusion moldability.

  In the present invention, the thickness of the surface layer (C) is generally preferably in the range of 0.5 to 2.0 mm. That is, if the thickness is too thin, characteristics such as killing resistance and weather resistance become unsatisfactory, and there is a possibility that use in the building field, for example, may be limited. Moreover, even if it is formed thicker than necessary, the properties such as killing properties are not improved, and the economic efficiency is deteriorated, or the base layer (A) derived from the expanded polystyrene is deteriorated, or the cutting process is performed. There is also a risk that the deterioration of the sex may occur.

  In the present invention, the surface layer (C) can also be blended with a colorant. For example, the colorant is blended with the intermediate layer (B) and the colorant is blended with the surface layer (A). As a result, the concealability can be improved and the color concealment of the base layer (A) can be ensured.

  The amount of the colorant used should be an amount that does not impair the properties of the surface layer (C). In particular, compared with the intermediate layer (B) described above, the surface layer (C) is colored. Since the blending of the agent has a great influence on the surface properties such as scratch resistance, the amount is preferably smaller than that of the intermediate layer (B), and generally 20 parts by weight or less per 100 parts by weight of the acrylonitrile styrene copolymer resin. It is good to do.

  In addition, in this invention, when mix | blending a coloring agent with an intermediate | middle layer (B) and surface layer (C), it is good to adjust the compounding quantity of a coloring agent within the range mentioned above according to the thickness of each layer. That is, as the thickness of each layer increases, the hiding power increases, so that the hiding power can be increased by reducing the blending amount of the colorant.

<Manufacture of extrusion molding>
In the present invention, the target extrusion-molded product can be produced by three-layer coextrusion using the resin composition or resin for forming each layer described above.

  For example, an extruder for forming a base layer, an extruder for forming an intermediate layer, and an extruder for forming a surface layer are prepared, and if necessary, the resin composition or resin that forms each layer is dry-blended, and then placed in the hopper of the extruder. It can be supplied, melt kneaded in an extruder, and coextruded through a predetermined die to obtain an extruded product having a desired shape. As the extruder, a known extruder having a single-screw or a twin-screw is used.

  As for the base layer (A), foaming can be performed outside the extruder in advance, but generally, foaming is performed simultaneously with extrusion by performing melt-kneading in the extruder at a temperature higher than the decomposition temperature of the foaming agent. Is preferred.

  Thus, the extrusion molding of the present invention in which the surface layer (C) is formed through the intermediate layer (B) on the base layer (A) having a foaming ratio of 1.1 to 5.0 times and being lightweight. can get. Such an extrusion-molded body has excellent lightness, scratch resistance and chemical resistance, as well as excellent cutting workability. For example, even when cutting with an electric saw or the like, it is almost free of burrs. Does not occur. Therefore, such an extrusion-molded product is optimal for use as an interior material for buildings or an exterior material.

The invention is further illustrated in the following examples. The following examples are illustrative and the invention is not limited in any way.
Various components used in the following examples and comparative examples are as follows.

<Base layer forming component>
(A1) Polystyrene (PS)
Recycled products
MFR: 5.0g / 10min
(A2) Styrenic elastomer Styrene / ethylene / butadiene / styrene block copolymer (SEBS)
(A3) Polyethylene resin
MFR: 3.5g / 10min
(A4) Polypropylene resin (PP)
MFR: 3.5g / 10min
(A5) Blowing agent Sodium bicarbonate Azodicarboxamide (ADCA)

<Ingredient for forming the intermediate layer>
MS1: Methyl methacrylate / styrene copolymer resin (Planeloy KM-6A)
MVR: 10cm ³ / 10min
Methyl methacrylic content: 60%
Styrene content: 40%
MS2: Methyl methacrylate / styrene copolymer resin (Denka TX-800F)
MVR: 25cm ³ / 10min
Methyl methacryl content: 50%
Styrene content: 50%
MS3: Methyl methacrylate / styrene copolymer resin (Ceviane MAS30)
MVR: 13cm ³ / 10min
Methyl methacrylic content: 60%
Styrene content: 40%
MS4: Methyl methacrylate / styrene copolymer resin (Cebian MAS10)
MVR: 22cm ³ / 10min
Methyl methacryl content: 20%
Styrene content: 80%
Acrylic TPE; Acrylic elastomer (Amzel AZ1803 manufactured by Plustech Co., Ltd.
N)

<Surface layer forming component>
ASA; Acrylonitrile / acrylic rubber / styrene copolymer manufactured by UMG-ABS
Compound resin: Diamond rack E310
MVR: 13cm ³ / 10min
SAS: Acrylonitrile / silicone-modified acrylic rubber manufactured by UMG-ABS Co., Ltd.
/ Styrene copolymer resin: Dialac E359A
MVR: 4.5cm ³ / 10min
PMMA; Methyl methacrylate resin HT01Y manufactured by Sumitomo Chemical
MFR: 2g / 10min

(Experimental Examples 1-9)
Various components are charged into the base layer forming extruder, the intermediate layer forming extruder and the surface layer forming extruder at the weight ratios shown in Table 1, and melt-kneaded at a cylinder temperature of 180 to 230 ° C, respectively, and co-extruded. Thus, a three-layer extruded body having a shape of 10 × 100 × 1000 mm was produced (the thickness of each layer is shown in Table 1).
The obtained molded body was measured for the foaming ratio, adhesion, cutting workability, and concealing property of the base layer by the following methods. The results are shown in Table 1.

(1) Foaming ratio It calculated from specific gravity and density.
In addition, the specific gravity adopted the calculated value also from each material, and the density was measured based on the underwater substitution method of JISK7112.
(2) Adhesion The peeled surface was observed and evaluated by a surface peel test.
○: The base layer breaks down.
X: Peel between resin layers.
(3) Cutting property The molded body was cut with an electric saw for woodworking, and the amount of burrs on the cut surface was visually evaluated.
○: Almost no burrs.
X: A lot of burrs were generated.
(4) Concealment In addition to the formulation of each component shown in Table 1, 5 to 15 parts by weight of white colorant is added to the intermediate layer, and 2 parts by weight of the same white colorant is added to the surface layer, and the color of the base layer Was determined from the surface side.
○: The color of the base layer is not visible at all.
Δ: The color of the base layer is slightly visible.
X: The color of the base layer is clearly visible.

Claims (11)

In a three-layer extrusion molded body formed by co-extrusion of three layers of an expanded polystyrene base layer (A), an acrylic styrene intermediate layer (B), and an acrylonitrile styrene surface layer (C),
The expanded polystyrene base layer (A) is
(A1) 100 parts by weight of polystyrene having a melt flow rate (MFR) of 0.1 to 20 g / 10 min,
(A2) Styrenic elastomer 5 to 30 parts by weight,
(A3) 2.5 to 30 parts by weight of polyolefin resin,
And has a foaming ratio of 1.1 to 5.0 times,
The acrylic styrene intermediate layer (B) is formed from an acrylic styrene copolymer resin having at least an acrylate unit and a styrene unit,
The acrylonitrile styrene surface layer (C) is formed from an acrylonitrile styrene copolymer resin having at least an acrylonitrile unit and a styrene unit,
A three-layer extrudate.   The three-layer extrusion molded article according to claim 1, wherein the polyolefin resin (A3) has an MFR in the range of 0.1 to 20 g / 10 min and in the range of 0.1 to 10 times the MFR of the polystyrene.   The three-layer extrusion molded article according to claim 2, wherein 25% by weight or more of the polyolefin resin (A3) is polyethylene.   The three-layer extrusion molded article according to claim 3, wherein the polyolefin resin (A3) contains polyethylene (PE) and polypropylene in a weight ratio of PE / PP = 75/25 to 25/75.   The three-layer extrusion molded article according to claim 1, wherein the acrylic styrene copolymer resin contains 50% by weight or more of acrylic units and 20% by weight or more of styrene units.   The three-layer extrusion molded article according to claim 5, wherein the acrylic styrene copolymer resin is a methyl methacrylate / styrene copolymer resin.   The three-layer extrusion molding according to claim 1, wherein the acrylic styrene-based intermediate layer (B) contains an acrylic elastomer in an amount of 2.5 to 25 parts by weight per 100 parts by weight of the acrylic styrene-based copolymer resin. body.   3. The acrylonitrile styrene copolymer resin is a copolymer resin having an acrylate unit, a styrene unit and an acrylonitrile unit or a copolymer resin having a silicone unit, an acrylate unit, an acrylonitrile unit and a styrene unit. Layer extrusion molding.   The acrylic styrene-based intermediate layer (B) contains a colorant in an amount of 30 parts by weight or less per 100 parts by weight of the acrylic styrene-based copolymer resin, and the acrylonitrile styrene-based surface layer (C) is the acrylonitrile styrene. The three-layer extrusion molded article according to claim 1, comprising a colorant in an amount of 20 parts by weight or less per 100 parts by weight of the copolymer resin.   The base layer (A) has a thickness of 3 to 50 mm, the intermediate layer (B) has a thickness of 0.1 to 1.0 mm, and the surface layer (C) has a thickness of 0.5 to 2.0 mm. The three-layer extrudate according to claim 1 having a thickness.   The three-layer extrusion molded article according to claim 1, which is used as an architectural interior material or exterior material.