JPS61233061A - Composite resin composition and production thereof - Google Patents

Abstract

PURPOSE:To provide the titled composition obtained by compounding a thermoplastic resin with a wood-based filler and a highly water-absorbing resin at specific ratios, and capable of giving a molded article having woody appearance and soft feeling without forming an article having defective appearance nor causing molding troubles. CONSTITUTION:The objective composition is produced by mixing (A) a wood- based filler (preferably sawdust or wood shavings having small size) uniformly with (B) a highly water-absorbing resin (e.g. a starch-acrylonitrile graft polymer, etc., preferably having fine particle size) and compounding the mixture with (C) a thermoplastic resin (e.g. polyolefin resin, vinyl resin, acrylic resin, polyamide, ABS resin, polybutadiene, etc.). The amounts of the component A and the component B in the composition is 10-100 pts. (wt.) and 0.3-10 pts. per 100 pts. of the component C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a resin composition containing a wood filler and a method for producing the same. Part 1: Specifically, it relates to a composite resin composition comprising a thermoplastic resin, a wood filler, and a superabsorbent resin, and its manufacturing method C:.

Traditionally, resin compositions made by blending thermoplastic resins with wood fillers such as wood flour have been used as molded products for automotive interior parts and home appliances because they have a soft feel and a woody appearance. Widely used as parts.

However, when molding using a molding method such as an extrusion molding method or an injection molding method at a temperature of 100°C or higher using a resin composition in which a thermoplastic thermoplastic resin second wood is blended with a single C2, the wood Moisture contained in the filler evaporates, significantly impairing the appearance of the resulting molded product, and in some cases making it impossible to mold it. For this reason, before mixing the wood filler to be used with the thermoplastic resin (either by completely drying it before use, or by coating the wood filler with a thermosetting resin, for example, and then mixing it with the thermoplastic resin). is disclosed in Japanese Patent Application Laid-Open No. 58-204050.

However, in order to completely dry the wood filler,
It requires a large amount of heat and large-scale drying equipment, making it economical (:), and if the dried wood filler is left alone, it immediately absorbs moisture, so it has to be used immediately after drying. .

Furthermore, when a wood-based filler is coated with a thermosetting resin, the resulting cured coating must be pulverized, and the cost of pulverization is several times that of the raw wood-based filler, making it difficult to put into practical use. There are also problems in terms of production and economics.

The present inventors have conducted extensive research to solve the above-mentioned problems with thermoplastic resins containing wood-based fillers. the result,
After mixing the wood filler with a small amount of super absorbent resin, a thermoplastic resin (C) is further added to this and the resulting resin composition is mixed with the wood filler + moisture caused by the two during molding. Therefore, it was discovered that a molded product with a wood-like appearance and soft feel can be produced without causing defects in the appearance of the molded product or troubles during molding, and based on this knowledge, the present invention was completed.

As is clear from the above description, the purpose of the present invention is to avoid troubles caused by moisture content of the wood filler during molding, and to prevent the resulting molded product from having poor appearance. An object of the present invention is to provide a thermoplastic resin composition containing a wood-based filler and a method for producing the same.

The present invention has the following configuration.

(1) A composite resin composition characterized in that 10 to 100 parts by weight of a wood filler and 0.3 to 10 parts by weight of a superabsorbent resin are blended with 100 parts by weight of a thermoplastic resin.

(2) A composite characterized in that a wood filler and a super absorbent resin are mixed, and after the super absorbent resin and wood filler are sufficiently mixed and dispersed, a thermoplastic resin is subsequently added and mixed. Method for producing resin composition.

The two-phase thermoplastic resin of the present invention (C) is not particularly limited; for example, polyethylene, polypropylene, ethylene-
Polyolefin resins such as propylene copolymers, polybutene and polystyrene, vinyl resins such as polyvinyl chloride and polyvinylidene chloride, polymethyl methacrylate,
Acrylic resins such as polyacrylate, polyamides,
Synthetic resins such as polyurethane, polycarbonate, and human BS resin, ethylene-vinyl acetate copolymer, styrene-butadiene copolymer, and polybutadiene.

Examples include polyisoprene.

By the way, the decomposition start temperature of wood fillers is 150
Since the thermoplastic resin has a temperature around 2°C, it is preferable to use a type of thermoplastic resin that can be molded at as low a temperature as possible, and generally a type that has a low polymerization time and high melt flowability is preferable. Since polyvinyl chloride has relatively poor fluidity, it is preferable to use a plasticizer such as di-2-ethylhexyl phthalate in combination to improve the melt fluidity of the resin.

The wood-based filler used in the present invention is not limited by the scale of the raw wood, and the particle size of the filler is also not limited to the specific C2, but it is preferably as fine as possible. 2. It is preferable to use cutting/saw scraps, polishing scraps, etc. of plywood. The amount of the wood filler added is 10 to 100 parts by weight, more preferably 20 to 80 parts by weight, particularly preferably 30 to 60 parts by weight, based on 100 parts by weight of the thermoplastic resin. If the amount added is less than 10 parts by weight, the economic effect of adding the wood-based filler is small, and when the molded product is formed, the wood-like appearance and soft feel of the molded product are not sufficiently expressed, which is not preferable. Moreover, if the amount added exceeds 100 parts by weight, the mechanical strength of the molded product decreases, making it unsuitable for practical use, which is not preferable.

Examples of superabsorbent resins used in the present invention include starch-based resins such as starch-acrylonitrile graft polymers and starch-acrylic acid graft polymers, and cellulose-based resins such as CMC crosslinked products such as Aqualon (trade name) and Accel (trade name). Resins and polyacrylate-based resins, polyacrylonitrile hydrolysates, vinyl acetate-acrylate copolymers such as Sumikagel, Igetagel (all trade names),
Examples include synthetic resins such as polyvinyl alcohol-maleic anhydride copolymer, inbutylene-maleic anhydride copolymer such as KI gel (trade name), polyethylene oquinide resin such as Aquabrene (trade name), and any Although a super absorbent resin may be used, it is preferable that the particle size of the super absorbent resin is fine because it is easier to disperse the wood filler surface C evenly.

The amount of super absorbent resin added is 1 to 1 of the wood filler used.
It may be 0% by weight, therefore, it is 0.1 to 10 parts by weight, more preferably 0.3 parts by weight, based on 100 parts by weight of the thermoplastic resin.
~5 parts by weight, particularly preferably 0.5 to 3 parts by weight.

If the amount added is less than 0.1 part by weight, the effect of dehydrating the water in the wood filler is small, and if it exceeds 10 parts by weight, the molded product will absorb moisture in the air and become deformed. , which is not suitable for practical use.

In the method for producing a composite resin composition of the present invention, first, a predetermined amount of a wood filler and a superabsorbent resin are sufficiently and uniformly mixed in a mixer. It is more effective to heat the mixer at this time. It is important that the thermoplastic resin and other additives are then added to the mixer and mixed again. After mixing a super absorbent resin, a thermoplastic resin, and other additives, and then adding and mixing a wood filler, or after mixing a thermoplastic resin, other additives, and a wood filler, The sufficient effects of the present invention cannot be obtained even if a thermoplastic resin and other additives, a super absorbent resin, and a wood filler are simultaneously mixed in a C2 mixer. do not have.

As the mixer, a Hensel mixer (trade name: Super Mixer Ribbon Plender, tumbler mixer, etc.) can be used, but it is preferable to use a mixer equipped with a device that can suck the internal space of the mixer.

When the composite resin composition of the present invention is molded by a molding method such as extrusion molding or injection molding, troubles due to moisture in the wood filler do not occur during molding, and the appearance of the molded product obtained is A molded product can be obtained that has a clean appearance without flash or flow marks, a wood-like appearance and a soft feel, and can be suitably used as parts for automobile interiors and household electrical appliances.

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples, but the present invention is not limited thereto. The evaluation method used in the Examples and Comparative Examples was the following Method C2.

1) Measurement of mechanical strength: Measurement of tensile strength and elongation (J
(based on IS K6745+2) ■) Measurement of glossiness: 90m length molded by injection molding method
A flat plate of 90 tms in width and 5 gourds in thickness is used as a test piece.Using a specular gloss meter, light is irradiated onto the test piece C2 at an angle of 60°, and the intensity of light when the reflected light is received at the same angle as the incident light. of,
It is expressed as a value (%) when the gloss of the glass surface with a refractive index of 1.567 is taken as 100.

n+) Appearance: Injection molding (: Height: 90m x Width: 90m
A flat plate having a thickness of 5 m and a thickness of 5 m is molded, and the appearance of the flat plate is visually observed for the presence or absence of flash and flow marks, and judged according to the following criteria.

O Wood texture, soft feel, no flash or flow marks.

Δ It has a woody and soft feel, with some flash and flow marks.

× It has a wood texture and a soft feel, but there are flash and flow marks.

XX There is no flash or flow mark, but there is no wood texture or soft touch.

Examples 1 to 3, Comparative Examples 1 to 3 As examples 1 to 3, 100 parts by weight of polyvinyl chloride as a thermoplastic resin, SB (average degree of polymerization 800),
20 parts by weight of di-2-etherhexynluphthalate (DOP), 3 parts by weight of a super absorbent resin (KI gel manufactured by Kureha Chemical Co., Ltd.), 2.5 parts by weight of dibutyltin malate as a stabilizer, 1 part by weight of dibutyltin mercaptide. In Example 1, 1 part by weight of stearic acid, 1 part by weight of polyethylene wax, and 20 parts by weight of wood flour (wood flour of Hoku tree, average particle size 200 μm) as a wood filler were added, and in Example 2, 50 parts by weight of wood flour were added. In Example 3, 80 parts by weight of wood flour is used. First, add the above-mentioned amount of wood flour and super absorbent resin, stir and mix at a jacket temperature of 100°C for 5 minutes, then add polyvinyl chloride, DOP, and a stabilizer. The mixture was stirred and mixed again for 5 minutes. The obtained mixture was melt-kneaded using a single-screw extruder with a diameter of 65 tm at a temperature of 180 ml.
The pellets were melt-extruded and pelletized at °C. Also, Comparative Examples 1 to 3
Comparative Example 1 had the same composition as Examples 1 to 3 except that wood flour and superabsorbent resin were not used, and Hensel Mixer (trade name) C: Polyvinyl chloride Example 2 had 5 parts by weight of wood flour. Comparative Example 3 had the same composition as Examples 1 to 3 except that 120 parts by weight of wood flour was used, and the mixtures were stirred and mixed in accordance with Examples 1 to 3 to obtain respective mixtures. These mixtures were melt-kneaded, extruded, and pelletized according to Examples 1 to 3C2. Pellets obtained in each of the experimental and comparison sides were injection molded at a cylinder temperature of 190° C. to obtain flat plates of predetermined dimensions. Using the obtained flat plate, specimens were prepared for examination of glossiness and appearance, and tensile strength and elongation were measured.

The above results are summarized in Table 1.

Examples 4 to 5, Comparative Examples 4 to 6 As Examples 4 to 5, melt index (amount of molten resin discharged in 10 minutes when applying a load of 2.16 Kp at a temperature of 190°C) was used as a thermoplastic resin. 23.0
100 parts by weight of high-density polyethylene powder polymer, wood flour (hemlock wood flour, average particle size 150μ) as a wood filler
0 parts by weight, 0.3 parts by weight of bisphenol as a stabilizer, 0.3 parts by weight of calcium stearate, and 0.3 parts by weight of 7Qualon (trade name) manufactured by Vercules as a super absorbent resin. , Example 5 uses 3.0 parts by weight. First, add the predetermined amount of super absorbent resin and wood flour mentioned above to Hensel mixer (product name) C2, and then add the jacket temperature to 1.
After stirring and mixing at 00° C. for 5 minutes, high-density polyethylene and a stabilizer were subsequently added, and the mixture was stirred and mixed again for 5 minutes at the jacket temperature of room temperature. The resulting mixture was
The mixture was melt-cross-extruded and pelletized using a m+ single-screw extruder at a melt-cross-wire temperature of 180°C. In addition, as Comparative Examples 4 to 6, Comparative Example 4 had the same composition as Examples 4 to 5 except that no superabsorbent resin was used. High-density polyethylene powder polymer, wood flour and Hensel mixer (trade name) were used. A predetermined amount of a stabilizer and a stabilizer were added thereto, and the mixture was stirred and mixed at room temperature for 5 minutes to obtain a mixture. Comparative Example 5 contains 0.05 parts by weight of super absorbent resin,
Comparative Example 6 had the same composition as Examples 4 and 5 except that 15.0 parts by weight of superabsorbent resin was used, and the mixtures were stirred and mixed in accordance with Examples 4 and 5 to obtain respective mixtures. These mixtures were melt mixed and extruded into pellets according to Examples 1 to 3. Using the obtained pellets, Examples 1-
A predetermined test piece was molded in accordance with No. 3, and its gloss, appearance, tensile strength, and elongation were measured. The above results are summarized in Table 2.

Example 6, Comparative Examples 7 to 9 Polyurethane (manufactured by Dainippon Ink ■,
T-5000V) 100 parts by weight, 50 parts by weight of wood flour (Lawan wood flour, average particle size 300μ) as a wood filler, and super absorbent resin (Sumikagel manufactured by Sumitomo Chemical ■) 1.0
Use parts by weight.

In Example 6, first, wood flour and super absorbent resin were placed in a Hensel mixer (trade name) and heated at a jacket temperature of 100°C for 5 minutes.
After stirring and mixing for a minute, polyurethane was subsequently added and the mixture was stirred and mixed again for 5 minutes at the jacket temperature of room temperature. The obtained mixture was melted in a single-screw extruder with a diameter of 65 mm at a temperature of 1
Pelletization was carried out at 80° C. by melt coextrusion. Also, comparative example 7
As shown in ~9, Comparative Example 7 was prepared by putting polyurethane, wood flour, and super absorbent resin into a Hensel mixer all at once, stirring and mixing at a jacket temperature of 100'C for 5 minutes, then returning the jacket temperature to room temperature and stirring again for 5 minutes. Mixed. Comparative example 8
First, polyurethane and wood flour were placed in a Hensel mixer (trade name) and stirred and mixed for 5 minutes at a jacket temperature of room temperature, followed by the addition of a super absorbent resin, and stirred and mixed again for 5 minutes at a jacket temperature of 100°C. In Comparative Example 9, polyurethane and a super absorbent resin were first put into a Hensel mixer (trade name), stirred and mixed for 5 minutes at a jacket temperature of room temperature, then a super absorbent resin was added, and the mixture was mixed again for 5 minutes at a jacket temperature of 100°C. Mix by stirring for a minute.

The resulting mixture was melt mixed and extruded into pellets according to the method of Example 6. Using the obtained pellets, test pieces were molded by the method according to Examples 1 to 3, and gloss, appearance, tensile strength, and elongation were measured.

The above results are summarized in Table 3 C.

As is clear from Table 1, the molded products obtained when the amount of wood filler used was within the scope of the present invention had a wood texture,
Although it had a soft feel and a clean appearance without flattening or flow marks, Comparative Example 1, which did not use a wood-based filler, and Comparative Example 2, which used a wood-based filler below the range of the present invention, The appearance of the obtained molded product was free of flash and flow marks, but it did not have a woody feel or soft feel. Although it has a woody feel and a soft touch, it was found that flattened flow marks often occurred, and both had problems in practical use.

Furthermore, as is clear from Table 2 (:, the molded products obtained in Comparative Example 1, in which no superabsorbent resin was used, and Comparative Example 2, in which the amount of superabsorbent resin used was below the range of the present invention, had a poor appearance. Flash and flow marks appeared to occur, and the tensile strength decreased due to foaming.Furthermore, in Comparative Example 6, in which a super absorbent resin was used beyond the scope of the present invention, flash and flow marks were observed in the molded product obtained. It was found that there were practical problems such as marks being visible and the molded product absorbing moisture.

As is clear from Table 3, in Example 6, in which the thermoplastic resin/wood filler and superabsorbent resin were mixed according to the method of the present invention, the appearance of the molded product was flash and flow marks. However, in comparisons using a mixing order other than the method of the present invention, some flash and flow marks were observed in the appearance of the molded products obtained, and it was found that they were not suitable for practical use.

As described above (:) When the composite resin composition of the present invention is used, there is no trouble caused by the water content of the wood filler during molding, and the molded product obtained has a woody feel and a soft touch. It was found that the product had a clean appearance with no flash or blow marks, and could be suitably used as parts for automobile interiors and home appliances.

Claims (2)

[Claims] (1) A composite resin composition characterized in that 10 to 100 parts by weight of a wood filler and 0.3 to 10 parts by weight of a superabsorbent resin are blended with 100 parts by weight of a thermoplastic resin. (2) A composite resin characterized by mixing a wood filler and a super absorbent resin, and after the super absorbent resin and wood filler are sufficiently mixed and dispersed, a thermoplastic resin is subsequently added and mixed. Method of manufacturing the composition.