JPS6247894B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a thermoplastic resin composition, and more specifically, the present invention relates to a method for producing a thermoplastic resin composition, and more specifically, the present invention relates to a method for producing a thermoplastic resin composition, and more specifically, the present invention relates to a method for producing a thermoplastic resin composition, and more specifically, an organic filler that is suitable for obtaining a molded product that has good filler dispersibility and pellet productivity, and has excellent appearance and mechanical strength. The present invention relates to a method for producing a thermoplastic resin composition containing a large amount. It has been proposed to blend various substances into thermoplastic resins for the purpose of improving the physical properties of thermoplastic resins, and one example is blending organic fillers such as wood flour. However, the upper limit of the amount of organic filler added to the thermoplastic resin is 40 to 50% by weight. If the amount is greater than this, it becomes difficult to produce pellets from the thermoplastic resin composition containing the organic filler, and the dispersibility of the filler also decreases significantly. Furthermore, when molded products are manufactured from such compositions, the appearance of the molded products may be poor due to moisture and decomposition gas in the organic filler, and the molded products may have poor mechanical properties, especially bending performance and impact performance. However, there were drawbacks such as low performance and variations in each part. An object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a method for producing a thermoplastic resin composition that contains a high amount of organic filler and that produces molded products with excellent appearance and mechanical properties. . That is, the present invention provides a chemically modified polyolefin (hereinafter simply referred to as "chemically modified polyolefin") obtained by chemically modifying 10 to 70 parts by weight of a thermoplastic resin, a polyolefin with a liquid rubber and/or an unsaturated carboxylic acid (including anhydride) or a derivative thereof. ) in a proportion of 5 to 15% by weight based on the organic filler is kneaded using a high-speed mixer, then kneaded using a low-speed mixer, and then kneaded using a single-screw extruder. This is a method for producing a thermoplastic resin composition characterized by extrusion. In the present invention, any thermoplastic resin can be used, but low melting point resins with a melting point of 190°C or less are particularly preferred, and examples of such resins include polyethylene, polypropylene, and copolymers mainly composed of ethylene and propylene. Examples include polyolefins such as polyolefins, polybutadiene, rubber-based resins such as styrene-butadiene-rubber, and ethylene-vinyl acetate copolymers. Among these, polyolefins such as polypropylene, low density polyethylene, high density polyethylene, and linear low density polyethylene are preferred. Examples of the organic filler include wood flour, crushed wood, fruit flour, and crushed waste paper, which may be used alone or in combination. Among these are pine, fir,
Wood flour and crushed wood made from natural wood such as hemlock and poplar are preferred. Organic filler has a particle size of 60~
A material of about 350 meshes, preferably 100 to 200 meshes, is used. Next, chemically modified polyolefin is polyolefin chemically modified with liquid rubber and/or unsaturated carboxylic acid (including anhydride) or a derivative thereof. Regarding this chemically modified polyolefin, for example, JP-A-54-123158,
It is described in Japanese Patent No. 54-124048, Japanese Patent No. 54-124049, etc., and those disclosed therein can be arbitrarily used. In the present invention, the above three components are thermoplastic resin 10
-70 parts by weight, preferably 20-40 parts by weight, 90-30 parts by weight, preferably 80-60 parts by weight of organic filler, and 5-15% by weight, preferably 7-15 parts by weight of chemically modified polyolefin based on the organic filler. Blend at a ratio of 10% by weight. In addition to the above three components, other components such as an ultraviolet absorber, a plasticizer, a lubricant, a flame retardant, an antistatic agent, and a coloring agent may be added as necessary. In the production method of the present invention, a blend of the above-mentioned raw material components is first kneaded using a high-speed mixer. in this case,
Kneading is carried out at a temperature of 100 to 250°C for 5 to 20 minutes, and the rotation speed of the high speed mixer is suitably 200 to 1000 rpm, preferably 400 to 900 rpm. Here the rotation speed is
If it is less than 200 rpm, gelation may be insufficient and kneading may not be possible, and if it exceeds 1000 rpm, the temperature of the raw material components may rise too much, leading to deterioration. Then knead with a low speed mixer. Kneading with a low-speed mixer is carried out at a temperature of 80-100°C for 5-10 minutes. There is no particular limit to the number of revolutions, but usually
The speed should be 100-200rpm. Since this kneading proceeds at a relatively low temperature, the kneaded material is gradually cooled and becomes fine lumps. After passing through the above two-stage kneading process, the kneaded product is kneaded and extruded using a single screw extruder. in this case,
It is desirable to carry out at a temperature of 190-230°C. In this step, it is important to perform not only a simple extrusion operation but also sufficient kneading. In this way, the method of the present invention performs kneading in three stages, but since the amount of components such as organic fillers added to the thermoplastic resin is large, greater power is required for kneading than in the case of ordinary resin compositions. shall be. Therefore, sufficient consideration should be given to the power source of the kneader and extruder used. The thermoplastic resin composition obtained by the above method is characterized by a large amount of organic filler blended with respect to the thermoplastic resin, and as mentioned above, it can be blended at a high ratio of up to 90% by weight. This is expected to be because the chemical reaction between the modified polyolefin and the wood flour forms strong ester bonds, and the wood flour is coated with the modified polyolefin, making it possible to mix and disperse large amounts in the resin. Ru. The thermoplastic resin composition obtained by the production method of the present invention is usually pelletized and then T-die extrusion molding.
It is made into a sheet by molding means such as press molding and calendar molding. Although the composition obtained by the present invention contains a large amount of organic filler, the dispersibility of the filler is improved, the productivity of pellets is good, and the molded product obtained has an appearance. , excellent mechanical properties, etc. Therefore, the composition obtained according to the present invention can be effectively used in applications such as automobile parts, audio parts, heavy/home appliance parts, food packaging materials, and miscellaneous goods. Next, the present invention will be explained in detail with reference to examples. Production example (Production of chemically modified polyolefin) Polypropylene (melt index 8 g/10 minutes, density 0.91 g/cm ² , product name:
J700G, manufactured by Idemitsu Petrochemical Co., Ltd.) per 100 parts by weight of terminal hydroxylated 1,4-polybutadiene (number average molecular weight 3000, trade name: poly BD B45HT,
(manufactured by ARCO Chem.Div.), 20 parts by weight of maleic anhydride, 1.72 parts by weight of dicumyl peroxide, and 600 parts by weight of xylene. 120℃,
The reaction was continued for 1 hour and then continued at 140°C for 3 hours. After the reaction was completed, it was cooled, precipitated in a large excess of acetone, filtered with suction, and dried (at 70°C).
50 hours) to obtain a white powder. Subsequently, this powder was placed in a Soxhlet extractor and extracted with acetone for 16 hours to remove unreacted polybutadiene and maleic anhydride to obtain a chemically modified polyolefin. Examples 1 to 28 Predetermined amounts of the thermoplastic resin, organic filler, and chemically modified polyolefin obtained in the production example shown in Table 1 were blended, and this mixture was supplied to a high-speed mixer heated to 150°C, and the rotation speed Stir for 15 minutes at 109 Km/hr, and the mixture is heated to 200 Km/hr by heat transfer and heat of stirring.
The temperature was raised to ℃ to cause gelation. Next, the above mixture was cooled in a low-speed mixer cooled to 20°C until the temperature reached 60°C, and the rotation speed was 50°C.
Stirred for 10 minutes at Km/hr. The kneaded material obtained in this way is passed through a single screw extruder (diameter 125 mm, vent type).
A rod-shaped resin composition was obtained by extrusion at a resin temperature of 200°C. Next, pellets (3φ×5
mm). The productivity of the pellets obtained,
The dispersibility of the organic filler was measured, and the pellets were processed into a T-die extrusion molding machine (manufactured by Toshiba Machine, vent type,
115 mmφ) to obtain an extruded sheet approximately 2 mm thick, and its surface appearance was visually evaluated. The results are shown in Table 1. The evaluation method was as follows. (1) Productivity of pellets (i) Uniformity of pellet shape Uniformity...〇 Partial collapse...△ Unevenness (powder formation, crumbling)...× (ii) Burnt/decomposition of pellets None...〇 1 Yes...△ Yes...× (2) Dispersibility of organic filler in pellets 500μ in a disk (100mmφ, thickness 200-300μ)
Judgment was made based on the number of the above foreign objects (wood blocks) present: 10 or less...〇 10-30 pieces...△ 30 or more pieces...Displayed as ×. (3) Appearance of molded product A box with length 260mm, width 100mm, depth 40mm, thickness 3mm, gate 3mmφ (direct gate) is molded using an injection molding machine, and the appearance is visually judged Beautiful...〇 Slight silver near the gate Occurrence of marks...
△ Silver, with a lot of foam... × In the table, △(a) indicates that the bottom of the box is slightly raised, that is, the bottom of the box is slightly raised. (4) Mechanical properties of molded products Tensile test: in accordance with ASTM D-638, Izod impact test: in accordance with ASTM D-256 Comparative Examples 1 to 13 The specified amounts of thermoplastic resin and organic filler shown in Table 1 and Pellets and sheets were obtained in the same manner as in the Examples, with or without blending a predetermined amount of the chemically modified polyolefin obtained in the Production Examples. The results are shown in Table 1. The evaluation method is the same as in the examples.

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Claims (1)

[Claims] 1. 10 to 70 parts by weight of thermoplastic resin, 90 parts by weight of organic filler
~30 parts by weight and chemically modified polyolefin, which is obtained by chemically modifying polyolefin with liquid rubber and/or unsaturated carboxylic acid (including anhydride) or a derivative thereof, in a proportion of 5 to 15% by weight based on the organic filler. 1. A method for producing a thermoplastic resin composition, which comprises kneading the mixture using a high-speed mixer, then kneading it using a low-speed mixer, and then kneading and extruding it using a single-screw extruder. 2. The manufacturing method according to claim 1, wherein the thermoplastic resin is a resin having a melting point of 190°C or lower.