JP2003321563A - Foamable resin composition filled with wood-based filler and molded foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a foamable resin composition highly containing a wood- based filler and provide a molded foam highly filled with the wood-based filler produced by foaming the same. <P>SOLUTION: The foamable resin composition comprises 10-50 wt.% thermoplastic resin, 50-80 wt.% wood-based filler, 0.1-10 wt.% foaming agent, 1-10 wt.% lubricant and 1-40 wt.% high molecular acrylonitrile-styrene copolymer (AS resin). The molded foam highly filled with the wood-based filler is provided by foaming the foamable resin composition. The molded foam highly filled with the wood-based filler has 1.2-3 times average apparent expansion ratio. A synthetic resin laminate is provided by laminating a non-foamed resin layer on the surface of the molded foam highly filled with the wood-based filler. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foamable resin composition filled with a high amount of wood filler and a foamed molded product obtained by foaming and molding the resin composition.

[0002]

2. Description of the Related Art A resin composition in which a synthetic resin is highly filled with a wood filler, particularly wood powder in order to impart a wood texture, is well known. Further, a technique of foaming a synthetic resin for the purpose of reducing the weight of the synthetic resin and imparting workability such as nailing and sawing is also well known. Furthermore, by combining these technologies, it is attempted to give a synthetic resin a wood-like feel, to impart workability such as nailing and sawing, and to foam a resin mixed with wood powder in order to further reduce the weight. Has also been done. However, when a large amount of wood powder or the like is present in the resin composition containing the foaming agent at the same time, it is difficult for bubbles generated from the foaming agent to keep a certain bubble shape, and the foam often breaks by coming into contact with the wood powder. For this reason, it has been difficult to obtain a foamed molded product containing fine and uniform cells, particularly a resin portion having a foaming ratio of 1.2 times or more with a resin composition containing a large amount of wood powder or the like in the composition.

Several attempts have already been reported to obtain a foamable resin composition containing wood powder and capable of obtaining a good foamed molded product. JP-A-10-182911 discloses that (A) 100 parts by weight of vinyl chloride resin, (B)
Methyl methacrylate copolymer containing 60% by weight or more of methyl methacrylate units, having a glass transition point of the copolymer of 50 to 90 ° C. and a non-viscosity of 1.5 to 4.0.
~ 30 parts by weight, (C) a pyrolytic foaming agent 0.1 to 3.0 parts by weight, and a vinyl chloride resin composition comprising 5 to 150 parts by weight of wood powder having an average particle size of 50 to 500 µm. Have been described. Japanese Patent Laid-Open No. 2001-98114 discloses AES.
A low-foaming resin composition containing 5 to 40 parts by weight of wood powder and 5 to 30 parts by weight of an inorganic filler with respect to 100 parts by weight of a resin is described. JP-A-2001-192489 discloses that resin 10 to 50% by weight, wood powder 50 to 90% by weight, foaming agent
A foamable resin composition containing 1 to 10% by weight and 1 to 40% by weight of a high molecular weight acrylic processing aid having an average molecular weight of 500,000 to 5,000,000 is described. Japanese Patent Laid-Open No. 2002-11
In Japanese Patent No. 816, the surface layer of the two-layer extruded product is ABS resin 90 to 20%, wood powder 10 to 80%, and foaming agent 0.1 to 1.
Parts, polymer processing aids with an average molecular weight of 500,000 to 5,000,000 1
A foamable resin composition containing 20 parts of high wood powder is described.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a foamable resin composition containing a wood filler in a high content, and a foam-molded product containing wood filler highly filled, which is obtained by foam molding the same. Is provided.

[0005]

The present invention is directed to a thermoplastic resin of 10 to 50% by weight, a wood filler of 50 to 80% by weight, a foaming agent of 0.1 to 10% by weight, a lubricant of 1 to 10% by weight, and a high molecular weight acrylonitrile. The present invention relates to a foamable resin composition containing 1 to 40% by weight of a styrene copolymer resin (AS resin). The present invention also relates to a wood filler highly-filled foam molded article obtained by foam molding the above foamable resin composition. More specifically, the present invention relates to the above wood filler highly filled foamed molded product having an average apparent expansion ratio of 1.2 to 3 times.
Furthermore, the present invention relates to a synthetic resin laminate in which a non-foamed resin layer is laminated on the surface of the above wood filler highly filled foamed molded product.

The molded product obtained according to the present invention has a fine and uniform air bubble formed in the resin layer even though it is highly filled with a wood filler, and has an aesthetic appearance that is lightweight and has a wood texture. It has excellent workability with excellent nailing and sawing properties. In addition, a laminate in which a non-foamed resin layer is laminated on the surface of the laminate can be given various design characteristics and surface characteristics by selecting the hardness, gloss, transparency, thickness, etc. of the non-foamed resin. It can be used for a wide range of purposes.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The expandable resin composition of the present invention comprises a thermoplastic resin of 10 to 50% by weight and a wood filler of 50 to 80.
%, A blowing agent 0.1 to 10% by weight, a lubricant 1 to 10% by weight, and a high molecular weight acrylonitrile styrene copolymer resin (AS resin) 1 to 40% by weight. A feature of the present invention is that a high molecular weight AS resin is added as a processing aid. A resin composition containing a large amount of a filler such as wood powder has a very low melt elongation, and the gas generated from the foaming agent does not remain as bubbles to form foam cells. By blending the high molecular weight AS resin, the melt elongation of the wood powder-containing resin composition is improved, and a good foam can be obtained without breaking the foam cells even when a large amount of wood powder is mixed. In addition, since the viscosity of the resin composition increases, the swell peculiar to the polymer material increases, and the shapeability of extrusion molding also improves. The weight average molecular weight of the high molecular weight AS resin is preferably 3,000,000 to 9,000,000. When the weight average molecular weight of the AS resin to be blended is lower than 3,000,000, bubbles generated in the composition having a large blending amount of the wood filler as in the present invention tend to be broken and it is difficult to obtain a good foam.

As the AS resin, any commercially available AS resin having the above average molecular weight range can be used. This AS
The resin is preferably mixed in the range of 15 to 80 parts by weight with respect to 100 parts by weight of the thermoplastic resin.

For thermoplastic resins, ABS that can be extruded
(Acrylonitrile-butadiene-styrene copolymer resin), AAS resin (acrylonitrile / acrylic rubber /
Styrene), AES resin (acrylonitrile / ethylene propylene rubber / styrene), AS resin (acrylonitrile / styrene), PS resin (polystyrene resin), P
MMA resin, PVC resin, MS resin (methyl methacrylate / styrene resin), PP (polypropylene resin),
Any resin such as PE (polyethylene resin), PBT (polybutylene terephthalate resin) and PC resin (polycarbonate resin) can be used. Particularly preferable thermoplastic resin is ABS, AAS, AES, AS, PS or MS because of its excellent compatibility with the AS resin. These thermoplastic resins are contained in the composition in the range of 10 to 50% by weight. If it is less than 10% by weight, not only the moldability but also a good foam cannot be obtained,
The strength of the molded body also decreases. Further, ABS, which is particularly in demand as a building material mixed with a wood filler, has the advantage that it is easy to recycle after use because it has the same component as the thermoplastic resin whose main component is high molecular weight AS.

The wood filler used in the present invention means a powdery or granular material of a substance containing cellulose as a main component, for example, powdery or granular material such as wood, bamboo, rice husk, kenaf, pulp, paper, lint, and cellulose fiber. Is mentioned. The wood filler preferably has an average particle size of 10 μm to 3 mm, particularly 50 to 500 μm. If it is too fine, the wood texture is hard to develop, and if it is too coarse, the obtained molded article becomes non-uniform and the appearance and physical properties deteriorate. Particularly preferred wood filler has an average particle size of 100.
˜250 μm wood flour. Wood filler in the composition,
50 to 80% by weight is blended.

The foamable resin composition of the present invention further contains a foaming agent and a lubricant as essential components. As the foaming agent, any of those which have been conventionally used as a foaming agent for foamed plastics can be used, which is a type that decomposes by heating or generates a gas by a physical change. Examples of these include, but are not limited to, sodium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium borohydride, azo compounds, nitroso compounds, hydrazide compounds, and the like. A self-expanding foaming agent such as a foaming agent or a microcapsule containing a high-pressure gas therein may be used. The foaming agent is blended in the foamable resin composition in an amount of 0.1 to 10% by weight.

As the lubricant to be blended in the composition of the present invention, any of those usually used in extrusion molding of general-purpose synthetic resins can be used. Examples of these lubricants are metal soaps such as calcium stearate, magnesium stearate and zinc stearate; fatty acid esters such as stearic acid monoglyceride and stearyl stearate; fatty acid amides such as stearic acid amide and methylenebisstearic acid amide. Hydrocarbons such as polyethylene wax and paraffin; higher alcohols such as stearyl alcohol and higher fatty acids such as stearic acid. The lubricant is blended in the composition in the range of 1 to 10% by weight.

To improve the foamability, talc, calcium carbonate, wollastonite, clay, calcium silicate or the like may be added as a foam nucleating agent to the resin composition of the present invention, if necessary. In addition to the above essential components, the resin composition of the present invention may contain other additives such as an antioxidant, a coloring agent, and a gelation accelerator, if necessary.

The composition of the present invention is a powder mixture in which all raw materials are powder-mixed at room temperature or at a temperature within the range where the foaming agent is not decomposed, and the powder mixture is directly supplied to an extrusion molding machine for molding a molded body. Or, the raw material components except the foaming agent may be powder-mixed at room temperature, then kneaded in advance with a single-screw or twin-screw kneader to form pellets, and then the mixture of the pellets and the foaming agent is put into an extruder. May be supplied. In any case, the MFR is not always necessary.
It is more preferable to add 5 to 70 parts by weight of a low molecular weight AS resin of 100 to 500 g / 10 min to the wood filler in order to improve the compatibility between the wood powder and the resin. Particularly preferably, the mechanical strength of the molded product is improved by mixing the wood powder and the low molecular weight AS resin in advance and then performing the two-step mixing in which the other components are added.

The wood filler highly filled foamed molded article of the present invention is obtained by mixing the above-mentioned foamable resin composition as a powder mixture, or by kneading and crushing or pelletizing it in advance, at a moldable temperature of the resin component. In addition, it can be produced by using a usual thermoplastic resin foam molding method which is performed by heating to a temperature at which the foaming agent decomposes to generate bubbles. Particularly preferred molding methods are extrusion foam molding and pressure molding methods.

The foamed molded article of the present invention can be formed into a flat plate, a columnar shape, a hollow shape, a profile extrusion shape, or the like. For example, a flat plate with ribs as shown in FIG. 1 is a preferred form of the foamed molded product of the present invention. The wood-filler highly-filled foamed molded product thus obtained is a highly foamed and homogeneous foamed product which could not be obtained by a wood-filled highly foamed product containing 50% by weight or more of wood powder. The average apparent expansion ratio of the foam is 1.2 to 3 times.

Another form of the molded product of the present invention is a synthetic resin laminate in which a non-foamed resin layer is laminated on the surface of the foamed molded product filled with wood filler. An example of this is shown in FIG.
Is shown in. By using such a laminated body, it becomes possible to impart surface design or to reinforce the foamed molded product with high filling of wood filler. This laminated body may be formed by pre-molding the above-described foam filled molded product with high filling of wood filler, and then laminating a surface resin layer on the surface thereof by a method such as adhesion or coating, or a foam molded product with high filling of wood filler. The layer and the surface resin layer can also be laminated by a simultaneous multilayer extrusion method.

For the surface resin layer, a transparent, semitransparent or opaque resin or resin composition can be used. When the multi-layer extrusion molding is performed simultaneously with the foamed high-density wood filler layer, an extrusion-moldable thermoplastic resin or resin composition is used as the surface resin layer.

[0019]

[Characteristics of raw materials used]

ABS resin: MFR = 15, powder, wood powder: coniferous wood 100 mesh or less (sieve opening 150
(μm) pulverized product, high molecular weight AS resin (AS processing aid): weight average molecular weight 7
, 000,000, powder foaming agent: sodium bicarbonate, lubricant: barium stearate. The foam molding conditions are as follows: [Molding conditions] Molding machine: Single screw extruder (screw diameter φ50 mm, L / D)
= 28), molding conditions: Cylinder temperature: C1: 160 ° C, C2: 170 ° C, C3: 180 ° C, size: 190 ° C Sizer: 15 ° C Circulating with cooling water Cooling screw rotation speed: 10 rpm Product shape: Variant width 150mm, thickness (non-rib part) 1
0 mm (Fig. 1). The foam extrudability was good and the appearance was also good. Table 1 shows the specific gravity and the average apparent expansion ratio of the molded product.

Example 2 Among the blended raw materials shown in Table 1, wood powder and low molecular weight AS resin were blended at room temperature for 3 minutes, and then ABS resin, high molecular weight AS resin as a processing aid, foaming agent and lubricant were blended. In addition, the mixture was further blended at room temperature for 3 minutes, the obtained powder mixture was supplied to an extruder, and extrusion molding was performed in the same manner as in Example 1. Similar to Example 1, the foam extrudability was good and the appearance was also good. Table 1 shows the specific gravity and average apparent expansion ratio of the molded product.
Described in. The properties of the low molecular weight AS resin used here are as follows: Low molecular weight AS resin: high flow AS resin of MFR300, powder.

Example 3 A powder mixture obtained by blending ABS resin, wood powder, high molecular weight AS resin and lubricant at room temperature was melt-kneaded with a biaxial kneader to prepare pellets of the present composition. Next, the masterbatch pellets of the foaming agent were mixed with the pellets of the present composition, stirred with a tumbler, and then fed to an extruder for extrusion molding in the same manner as in Example 1. The foam extrudability was good and the appearance was also good. Table 1 shows the specific gravity and the average apparent expansion ratio of the molded product.

Example 4 Extrusion molding was carried out in the same manner as in Example 1 except that the blending amounts of the high molecular weight AS resin and the ABS resin were changed to the amounts shown in Table 1. The foam extrudability was good and the appearance was also good. Table 1 shows the specific gravity and the average apparent expansion ratio of the molded product.

Example 5 A foamable resin composition was prepared in the same manner as in Example 1 except that 5% by weight of talc was added as a foaming aid in order to improve the foamability and the amount of ABS resin was reduced by that amount. Then, extrusion molding was performed. In the extrusion molding, simultaneous two-layer extrusion molding was carried out so that the PMMA resin layer was coated on one surface of the wood powder high-fill foam molding. The molding conditions are as follows: [Molding conditions] Molding machine: Foam layer extruder: Single screw extruder (φ50 mm, L / D = 2)
8) Extruder for surface layer: Single screw extruder (φ40 mm, L / D = 2)
8) Molding conditions: Cylinder temperature: C1: 160 ° C, C2: 170 ° C, C3: 180 ° C, Width: 190 ° C Sizer: 15 ° C Cooling water Circulation Cooling screw Rotation speed: 10 rpm Obtained synthetic resin laminate The cross-sectional structure is shown in FIG. In the figure, 1 is a resin layer of a foam-molded body highly filled with wood powder, and 2 is a surface resin layer. Table 1 shows the specific gravity and the average apparent expansion ratio of the foam-molded body portion highly filled with wood powder.

Example 6 Extrusion was carried out in the same manner as in Example 1 except that the ABS resin was changed to the PS resin and the extruder cylinder temperature was changed. Cylinder temperature: C1: 140 ° C., C2: 150 ° C., C3: 160 ° C., size: 160 ° C. Foam extrudability was good and appearance was also good. Table 1 shows the specific gravity and the average apparent expansion ratio of the molded product.

Comparative Examples 1 and 2 In Comparative Example 1, extrusion molding was performed in the same manner as in Example 1 except that the high molecular weight AS resin was not added. In addition, in Comparative Example 2, in addition to the compounding composition of Comparative Example 1, 5% talc was added as a foaming auxiliary agent.
Extrusion molding was carried out with the addition of wt%. In both cases, the foamed cells were ruptured and the extrusion molding according to the mold shape could not be obtained.

In the examples and comparative examples, the properties of the foamed molded articles were measured by the following methods. [Method for evaluating characteristics of foamed molded product] Specific gravity: JIS K 7112 A method. Apparent expansion ratio of water substitution method: Specific gravity of unfoamed product ÷ Specific gravity of foamed product

[0027]

[Table 1]

[0028]

INDUSTRIAL APPLICABILITY The molded product obtained according to the present invention forms a highly foamed resin layer having uniform and fine cells even though the wood filler is contained at a high filling rate of 50% by weight or more. In addition, it has an aesthetic appearance that is lightweight and has a wooden texture, and has excellent workability with excellent nailing and sawing properties. In addition, a laminate in which a non-foamed resin layer is laminated on the surface of the laminate can be given various design characteristics and surface characteristics by selecting the hardness, gloss, transparency, thickness, etc. of the non-foamed resin. Can
It can be used for a wide range of purposes.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a foamed molded product formed by extrusion molding of a wood filler highly filled according to the present invention.

FIG. 2 is a cross-sectional view of a two-layer extruded product in which a non-foamed resin layer is laminated on the surface of a wood filler highly-filled foamed product.

[Explanation of symbols]

1: Wood filler highly filled foamed molded product 2: Non-foamed resin layer.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // (C08L 97/02 C08L 101: 00 101: 00 25:12 25:12) (72) Inventor Akane Noriyuki 14-5 Shimokita-cho, Neyagawa-shi, Osaka Prefecture Kurashiki Spinning Co., Ltd. Technical Research Institute (72) Inventor Masahiro Tomishima 2-3-4, Kutaro-cho, Chuo-ku, Osaka-shi, Osaka Kurashiki Spinning Co., Ltd. Terms (reference) 4F074 AA02 AA09D AA13 AA13D AA17D AA24 AA32A AA32D AA36 AA48 AA48A AA49A AA67 AA70 AD01 AD04 AD09 AD10 AD11 AD13 AG11 BA03 BA04 BA12AK12A12 AK12A12B12BA12AK12A01B12BA12AK12A01B12BA12A12A12A12A12A12A12A12A15A17A18A12A12A12A12A15A12A25A12A25A12A12A12A25A12A12A12A25A1 AK27J AK42A AK45A AK74A AL01A AL05A AP00A AP00H BA02 BA10A BA10B BA15 CA01A CA19A CA23A DJ01A EH20 JA07A JA07H JA13A JB16A JL01 YY00A YY00H 4J002 AA012 AE033 AE053 AH0 01 BB022 BB112 BC032 BC062 BC064 BC072 BD032 BG062 BN062 BN122 BN152 CG002 DE206 DE226 DK006 EC067 EG037 EG047 EH037 EP007 EQ016 EQ026 ES006 FD062 FD173 FD177 FD326

Claims (8)

[Claims] 1. A thermoplastic resin 10 to 50% by weight, a wood filler 50 to 80% by weight, a foaming agent 0.1 to 10% by weight,
A foamable resin composition comprising 1 to 10% by weight of a lubricant and 1 to 40% by weight of a high molecular weight acrylonitrile-styrene copolymer resin (AS resin). 2. A high molecular weight acrylonitrile-styrene copolymer resin (AS resin) having a weight average molecular weight of 3,000,000 to 90.
The expandable resin composition according to claim 1, which has an amount of 0,000. 3. The thermoplastic resin is ABS, AAS, AE.
S, AS, PS, PMMA, PVC, MS, PP, P
The expandable resin composition according to claim 1, which is E, PBT, or PC. 4. The thermoplastic resin is ABS, AAS, AE.
The expandable resin composition according to claim 1, which is S, AS, PS or MS. 5. A wood-filler highly-filled foam-molded article obtained by foam-molding the foamable resin composition according to any one of claims 1 to 4. 6. The foamed molded product highly filled with wood filler according to claim 5, which has an average apparent expansion ratio of 1.2 to 3 times. 7. A synthetic resin laminate in which a non-foamed resin layer is laminated on the surface of the wood filler highly filled foamed molded article according to claim 5 or 6. 8. The synthetic resin according to claim 7, which is molded by a simultaneous multi-layer extrusion molding method in which the foamable resin composition according to any one of claims 1 to 4 is extrusion-foamed and at the same time a non-foamed resin is extrusion-molded. Laminate.