JP2002188005A - Polyphenylene sulfide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a PPS resin composition having excellent moldability, rigidity and dimensional accuracy and causing extremely little staining or corrosion of metals in the long-term continuous molding operation. SOLUTION: The polyphenylene sulfide resin composition for precision molding is produced by compounding (A) 100 pts.wt. of a polyphenylene sulfide resin with (B) 0.5-10 pts.wt. of magnesium oxide and (C) 10-400 pts.wt. of a fibrous filler, other inorganic filler or their mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyphenylene sulfide having excellent moldability such as injection molding, extremely low mold contamination or corrosion during long-term continuous molding, and excellent rigidity and dimensional accuracy. The present invention relates to a precision molding material made of a resin composition.

[0002]

2. Description of the Related Art Conventionally, metals such as aluminum die-cast and zinc die-cast have been used for precision parts such as optical parts, electronic / electric parts, and automobile parts. However, the cost of processing into a predetermined shape with high dimensional accuracy leads to an increase in the cost of the product, and in recent years, the use of thermoplastic resins, mainly engineering plastics, has been increasing. In other words, a large number of components can be continuously produced by injection molding even with a complicated shape, so that component production costs can be reduced, and the number of components can be reduced by integrating a plurality of components. Among the thermoplastic resins, polyphenylene sulfide resin (hereinafter, abbreviated as PPS) is excellent in heat resistance, dimensional stability, chemical resistance, flame retardancy, moldability, rigidity and dimensional stability in this application. , PP filled with high concentration of fibrous, plate-like, granular inorganic filler, etc.
S is used.

[0003] However, a disadvantage of PPS is that if the molding is performed for a long time, the mold is easily contaminated and corroded. This is because the structure of the PPS resin itself contains a sulfur component, and when the resin composition is heated and melted at the time of molding, the SOPS becomes SO2.
The generation of a gas containing a sulfur compound such as x and H ₂ S can be cited as a cause. When molding is performed using PPS resin, the corrosion of the mold proceeds faster than other resins. Therefore, man-hours and costs for maintenance or renewal of the mold are not negligible, and there is a strong demand for reducing the generation of gas that pollutes or corrodes the mold during molding of the PPS resin.

Various methods have been studied to reduce the gas generated during PPS molding. For example,
There are a method of adding a zinc compound to PPS and a method of adding fine-grained calcium carbonate, but the method has not yet led to the definitive reduction in generation of gas that contaminates or corrodes a mold.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a PPS resin composition which is excellent in moldability, rigidity and dimensional accuracy, and in which metal contamination or corrosiveness is extremely reduced during long-term continuous molding.

[0006]

According to the present invention, (A) 100 to 100 parts by weight of polyphenylene sulfide resin, (B) 0.5 to 10 parts by weight of magnesium oxide, (C) fibrous filler, other inorganic filler, Or a polyphenylene sulfide resin composition for precision molding, comprising 10 to 400 parts by weight of a mixture thereof.

The PPS resin used in the present invention is

[0008]

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Preferably, the composition contains at least 70 mol% of the structural unit represented by the formula: If the amount is less than 70 mol%, it is difficult to obtain a composition having excellent properties. As a polymerization method of the PPS resin, a method of reacting sodium sulfide with p-dichlorobenzene in an amide solvent such as N-methylpyrrolidone or dimethylacetamide or a sulfone solvent such as sulfolane is suitable. At this time, an alkali metal salt of a carboxylic acid or a sulfonic acid is added to adjust the degree of polymerization, or an alkali hydroxide, an alkali metal carbonate, or an alkaline earth metal oxide is added. If the amount of the copolymer component is less than 30 mol%, a meta bond, an ortho bond, an ether bond, a sulfone bond, a biphenyl bond, a substituted phenylene sulfide bond (where the substituent is an alkyl group, a nitro group, a phenyl group, an alkoxy group) , A carboxylic acid group, a metal base of a carboxylic acid), a trifunctional bond, etc., as long as it does not significantly affect the crystallinity of the polymer, but the copolymer component is preferably 10 mol% or less. The PPS resin is usually used after thermal crosslinking at 200 to 250 ° C. in the presence of oxygen to adjust the melt viscosity.

The amount of magnesium oxide used in the present invention is 0.5 to 10 parts by weight, more preferably 1 to 3 parts by weight, based on 100 parts by weight of the PPS resin. When the amount is less than 0.5 part by weight, the effect of mold contamination or corrosion is extremely small, and when the amount is more than 10 parts by weight, moldability or strength is reduced.

The fibrous filler used in the present invention includes glass fiber, carbon fiber, asbestos fiber, silica fiber, silica-alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, Inorganic fibrous substances such as potassium titanate fibers and fibrous materials of metals such as stainless steel, aluminum, titanium, copper, brass and the like. Other inorganic fillers include carbon black, silica, quartz powder, glass beads, glass powder, glass flake, calcium silicate, aluminum silicate, talc, clay, mica, diatomaceous earth, wollastonite and other silica fillers. Metal oxides such as acid salts, iron oxides, titanium oxides, zinc oxides, and aluminas; metal carbonates such as calcium carbonate and magnesium carbonate; metal sulfates such as calcium sulfate and barium sulfate; and other materials such as silicon carbide and silicon nitride , Boron nitride, various metal powders, and the like. Two or more of these fillers can be used in combination. In use, it is desirable to modify the particle surface with a surface treatment agent. Examples of the surface treatment agent include functional compounds such as epoxy compounds, isocyanate compounds, silane compounds, titanate compounds, and the like. The filler may be surface-treated with these compounds in advance or used at the same time as mixing the materials. The compounding amount of these fillers is PPS resin 10
It is 10 to 400 parts by weight, more preferably 50 to 300 parts by weight, based on 0 parts by weight. When the amount is less than 10 parts by weight, the effect of improving various properties is small, and when the amount is more than 400 parts by weight, moldability is significantly reduced.

Further, the composition of the present invention contains known substances which are generally added to thermoplastic resins and thermosetting resins, that is, stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents and flame retardants. Colorants such as dyes and pigments, lubricants, and the like can be appropriately added as necessary.

Although the method for producing the composition of the present invention is not limited, for example, it is also possible to weigh each component, mix it with a blender, a mixer, etc., melt-knead it with an extruder and pelletize it. Alternatively, the glass fiber may be kneaded and pelletized by being supplied in a fixed amount by a side feeder. The pellet-shaped molding material thus obtained is
It is usually molded into a desired shape by a widely used thermoplastic resin molding machine, injection molding machine, injection compression molding machine or the like and used.

[0014]

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 components used in Examples 1 to 5 and Comparative Examples 1 to 5 are as shown below. PPS resin: Trade name K-4 Magnesium oxide: Tateho Chemical Industry Co., Ltd. Product name H-10 Glass fiber: Nippon Sheet Glass Co., Ltd. RES03-TP29

The above components were blended according to the compositions shown in Tables 1 and 2, and melt-kneaded with a twin-screw kneader to form pellets. After the obtained molding material was dehumidified and dried at 140 ° C. for 5 hours, the cylinder temperature was 300 ° C., the injection pressure was 1200 kg / cm ² , the injection speed was medium, and the mold temperature was 140 using an injection molding machine (IS80 EPN manufactured by Toshiba Machine Co., Ltd.). Molding was performed under the condition of ° C. to prepare various test pieces. Using each test piece, bending strength,
The flexural modulus was measured according to the ASTM test method, and the Koka flow was measured according to JIS K7210. Regarding the gas reduction effect, the clearance part (width 5 m) provided around the cavity after performing 2000 shot molding with each material
m, a depth of 10 μm) was visually evaluated. The criterion for judging the mold contamination status is represented by ○: mold contamination (discoloration) ×: no mold contamination (no discoloration).

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

According to the present invention, it is possible to provide a PPS resin composition which has good moldability, rigidity, and dimensional accuracy, and does not cause or very little mold contamination or corrosion during molding. Such a resin composition can be used for precision parts such as optical parts of an optical pickup.

Claims (1)

[Claims] 1. A polyphenylene sulfide resin (A)
(B) magnesium oxide is added in an amount of 0.5 to 100 parts by weight.
10 parts by weight (C) fibrous filler, other inorganic filler,
Or, a polyphenylene sulfide resin composition for precision molding, comprising 10 to 400 parts by weight of a mixture thereof.