JP2002080728A - Method for producing molded article of thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a molded article of a thermoplastic resin composition composed of a thermoplastic resin composition containing a crystalline resin and an amorphous resin and having excellent chemical resistance and appearance. SOLUTION: The method for producing a molded article of a thermoplastic resin composition containing (A) a crystalline resin and (B) an amorphous resin having a glass transition temperature lower than the melting temperature of the resin A and forming a continuous phase at an A/B weight ratio of 1/99 to 60/40 comprises the molding of the composition under a condition satisfying the formula: Tma>Tf>=[Tma-(Tma-Tg)/3] wherein Tf is the molding temperature, Tma is the melting temperature of the component A and Tg is the glass transition temperature of the component B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a molded article of a thermoplastic resin composition. More specifically, the present invention relates to a method for producing a molded article of a thermoplastic resin composition comprising a thermoplastic resin composition containing a crystalline resin and an amorphous resin, and having excellent chemical resistance and excellent appearance. is there.

[0002]

2. Description of the Related Art For example, amorphous resins such as polyphenylene ether-based resins and polystyrene-based resins are excellent in dimensional stability and the like, and are excellent from the viewpoint of shape stability of molded articles. In addition, it has low resistance to chemicals such as detergents, and is not suitable for applications requiring chemical resistance. A technique for adding a crystalline resin to an amorphous resin to make up for this drawback has been disclosed. For example, a technique of adding an alkenyl aromatic resin having a syndiotactic structure to a polyphenylene ether resin is disclosed in
-64140. However,
Even if a polyphenylene ether-based resin is simply added, the alkenyl aromatic resin having a syndiotactic structure is hardly crystallized, and improvement in chemical resistance cannot be achieved. In order to solve such a problem, the mold temperature at the time of injection molding must be equal to or higher than (glass transition temperature of alkenyl aromatic resin having a syndiotactic structure −10 ° C.) (melting of alkenyl aromatic resin having a syndiotactic structure). Japanese Patent Application Laid-Open No. H11-5236 discloses a technique for performing high-frequency induction heating at a temperature of + 10 ° C. or lower, but cannot sufficiently increase the crystallinity, and has a small effect of improving solvent resistance. Furthermore, when the temperature of the mold during injection molding is high, there is a disadvantage that the cooling time until the molded product is taken out becomes long, and the productivity is deteriorated.

[0003]

SUMMARY OF THE INVENTION In view of such circumstances, an object of the present invention is to provide a thermoplastic resin composition containing a crystalline resin and an amorphous resin, which has excellent chemical resistance and appearance. Another object of the present invention is to provide a method for producing a molded article of a thermoplastic resin composition having excellent heat resistance.

[0004]

That is, the present invention comprises the following components (A) and (B) at a weight ratio of (A) / (B) of 1/99 to 60/40. (B) is a method for producing a molded article made of a thermoplastic resin composition in which a continuous phase is formed, and relates to a method for producing a molded article of a thermoplastic resin composition molded under the conditions of the following formula (1). Things. (A): crystalline resin (B): amorphous resin having a glass transition temperature lower than the melting temperature of (A) Tma> Tf ≧ [Tma− (Tma−Tg) / 3] (1) where Tf is a molding Represents temperature, Tma represents the melting temperature of component (A), and Tg represents the glass transition temperature of component (B).

[0005]

DETAILED DESCRIPTION OF THE INVENTION The component (A) is a crystalline resin, which is an alkenyl aromatic resin having a syndiotactic structure, a polyethylene terephthalate resin, a polybutylene terephthalate resin, a polyether ether ketone resin, and a polyacetal. Resin, polyamide resin,
Examples thereof include a polypropylene resin, a polyethylene resin, and a polyphenylene sulfide resin.

The component (B) is an amorphous resin having a glass transition temperature lower than the melting temperature of the component (A). As the amorphous resin, polyphenylene ether resin, polystyrene resin, polycarbonate resin, polyether sulfone resin, polyetherimide resin, acrylonitrile-
Examples thereof include butadiene-styrene resin (ABS resin), polysulfone resin, and polymethyl methacrylate resin.

As for (A) and (B), various combinations can be used. Further, a plurality of crystalline resins can be used in combination as (A). (B)
A plurality of amorphous resins compatible with each other can be used in combination. The term "compatible" as used herein means that when mixed, it shows a single glass transition temperature.

[0008] The thermoplastic resin composition of the present invention must have (B) a glass transition temperature lower than the melting temperature of (A).
The melting temperature of (A) and the glass transition temperature of (B) are J
Measured according to ISK7121. However, (A)
When a plurality of crystalline resins are used, the highest melting temperature among those melting temperatures is shown. When the glass transition temperature of (B) is higher than the melting temperature of (A), it is difficult to mold at a temperature lower than the melting temperature of (A).

In the thermoplastic resin composition of the present invention, (B) needs to form a continuous phase. If (B) does not form a continuous phase, the fluidity below the melting temperature of (A) is reduced, and molding below the melting temperature of (A) becomes difficult.

In the thermoplastic resin composition of the present invention, the weight ratio of (A) and (B) to (A) / (B) is from 1/99 to 60 /
40, preferably 3/97
４０40/60. If (A) is too small, the effect of improving chemical resistance is poor. on the other hand,
When (A) is excessive, heat resistance is deteriorated.

The thermoplastic resin composition of the present invention may contain dyes, pigments, antistatic agents, lubricants, antioxidants, weathering agents and the like. Further, the thermoplastic resin composition of the present invention may contain an inorganic filler such as calcium silicate, magnesium silicate, glass fiber, metal whisker, silica, calcium carbonate, wollastonite, talc, mica, and kaolin. Further, an amorphous resin that does not form a continuous phase can be added.

[0012] The method for producing the thermoplastic resin composition of the present invention is not particularly limited, and examples thereof include various methods such as a solution blending method and a melt kneading method. Among these, the melt kneading method is preferred. As a specific method, a method in which each component is melt-kneaded by a known kneading machine such as a Banbury mixer, a plast mill, a Brabender, a single-screw or twin-screw extruder, or the like can be exemplified. In kneading, the kneading temperature is usually 1
A range of 50 to 400C, preferably 200 to 350C is selected.

The method for producing a molded article of the thermoplastic resin composition of the present invention is characterized in that the molded article is molded under the condition of the following formula (1). Tma> Tf ≧ [Tma-{(Tma-Tg) / 3}] (1) where Tf represents a molding temperature, Tma represents a melting temperature of the component (A), and Tg is a glass transition of the component (B). Represents temperature.

When the molding method is injection molding or extrusion molding, Tf corresponds to the cylinder temperature of the injection molding machine or extruder. Generally, the cylinder temperature can be set for each of a plurality of zones.
It is necessary to set the above region to the temperature range of the above equation (1). When the molding method is press molding, Tf corresponds to the temperature of the press die, and it is necessary to substantially keep the entire surface within the temperature range of the above formula (1). When the molding method is calender molding, Tf corresponds to the set temperature of the calender roll.
In calendering, generally three or more calender rolls are used, but it is necessary that the number of rolls equal to or more than 1/2 be within the temperature range of the above formula (1).

The molding method used for producing the molded article of the thermoplastic resin composition of the present invention is not limited to the above-mentioned molding method. It is necessary to set the temperature of a region of at least half of the flow path to the temperature range of the above formula (1). The temperature of the mold part is calculated by the above equation (1).
It is necessary to set the temperature range.

When Tf is higher than Tma, the crystallization of the component (A) does not proceed sufficiently, and the effect of improving the chemical resistance is poor. Further, when Tf is [Tma-{(Tma-Tg)
/ 3}]], the fluidity of the resin composition is poor, the appearance of the molded product is deteriorated, and molding becomes difficult. That is, by adopting the condition of the above formula (1) of the present invention, crystallization of the component (A) is promoted, chemical resistance is improved, and a molded article having a good appearance can be obtained. .

The molded article of the present invention is used in fields where chemical resistance is required, for example, electric / electronic parts such as flyback transformers and deflection yokes, peripheral parts such as microwave ovens, etc.
For water supply / drainage / supply / exhaust parts such as pumps, tanks, ducts, etc.
It can be used for battery cases and other battery cases, tap water dispensers, developing tanks, fans and fan housings. In addition, automotive applications such as instrument panels, wheel covers, fuse holders, radiator grills, ignition coils, side mudguards, bumpers, etc., housings for OA equipment, chassis for OA equipment,
It can be used for mechanical parts such as trays and coin mechanical chassis of vending machines.

[0018]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The meanings of the abbreviations used in Examples and Comparative Examples are shown below. Component (A): PA polyamide 66 resin Trademark CM3
007 (manufactured by Toray Industries, Inc.) Melting temperature 255 ° C. (B) component: HIPS high impact polystyrene resin Trademark Sumibrite H554 (manufactured by Nippon Polystyrene Co., Ltd.) (B) component: SMA Styrene having a maleic anhydride content of about 8% -Maleic anhydride copolymer trademark DAILARK 232 (sold by Nova Chemical Japan)

Reference Example 1 Preparation of Composition 1 PA 10 wt%, HIPS 80 wt%, SMA 10 wt%
% In a twin-screw kneader TEM50A (manufactured by Toshiba Machine Co., Ltd.), cylinder temperature 280 ° C., screw rotation speed 200
After melt-kneading under the condition of rpm and extruding from the die,
The mixture was cooled in a water tank and pelletized with a strand cutter to obtain Composition 1. The continuous phase of Composition 1 was a compatible product of HIPS and SMA.

The glass transition temperature HIPS ( 88.8 wt%) and SMA 11.1 wt% of the component (B) are mixed in a twin-screw kneader TEM50A (manufactured by Toshiba Machine Co., Ltd.) under the conditions of a cylinder temperature of 230 ° C. and a screw rotation speed of 200 rpm. After melt-kneading and extruding from a die, the mixture was cooled in a water bath and pelletized with a strand cutter to obtain a composition. The temperature was raised at a rate of 10 ° C./min from 20 ° C. to 200 ° C. using a differential scanning calorimeter, and the glass transition temperature of the composition was measured in accordance with JIS K7121. The composition exhibited a single glass transition temperature, confirming that HIPS and SMA were compatible. The glass transition temperature of the composition is 10
2 ° C.

The methods for evaluating physical properties and the like are described below. Evaluation of crystallinity of molded products Samples were cut out from each molded product, and 20 to 300 ° C.
Then, the temperature was raised at 10 ° C./min, and the endothermic peak temperature and heat of fusion ΔH (J / g) at around 255 ° C. due to the PA crystal melting were measured in accordance with JIS K7121. Evaluation of chemical resistance Each molded product was attached to a semicircular jig having a curvature of 168 mm at 23 ° C., and a 20 × 12 mm gauze impregnated with salad oil was placed in the center of the test piece, and cracks were generated 60 minutes later. The presence or absence was visually evaluated. The state of occurrence of cracks after 60 minutes was evaluated as ○ (no crack occurred) and X (crack occurred).

Embodiment 1 C1, C2, C3, C3, C3
Injection molding machine (Cycap 1) divided into four zones of C4
10/50, manufactured by Sumitomo Heavy Industries, Ltd., the C1 to C4 temperatures were both set to 240 ° C., and at a mold temperature of 50 ° C., the thermoplastic resin composition 1 was injection molded to obtain an ASTM tensile No. 1 dumbbell. . Using the obtained test pieces, measurement of ΔH, chemical resistance test, and appearance evaluation were performed. Table 1 shows the results. Example 2, Comparative Example 1, and Comparative Example 2 Evaluation was performed in the same manner as in Example 1 except for the composition and molding conditions shown in Table 1. Table 1 shows the results.

[0023]

[Table 1] * 1: [Tma-{(Tma-Tg) / 3}]

[0024]

As described above, according to the present invention, a molded article of a thermoplastic resin composition comprising a crystalline resin and a thermoplastic resin composition containing an amorphous material, having excellent chemical resistance and excellent appearance. A manufacturing method could be provided.

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Claims (1)

[Claims] 1. The following components (A) and (B) are contained at a weight ratio of (A) / (B) of 1/99 to 60/40, and (B) forms a continuous phase. A method for producing a molded article made of the thermoplastic resin composition, wherein the molded article is molded under the condition of the following formula (1). (A): crystalline resin (B): amorphous resin whose glass transition temperature is lower than the melting temperature of (A) Tma> Tf ≧ [Tma− (Tma−Tg) / 3] (1) where Tf is a molding Represents temperature, Tma represents the melting temperature of component (A), and Tg represents the glass transition temperature of component (B).