JP2001072866A - Polyarylene sulfide resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition giving a resin having high rigidity, high modulus of elasticity and fluidity and alleviated coefficient of linear expansion in the thickness direction of molding product and anisotropy shrinkage percentage. SOLUTION: This polyarylene sulfide resin composition is obtained by compounding (A) 100 pts.wt. of a polyarylent suifide resin composition with (B) 5-200 pts.wt. of sericite and (C) 10-500 pts.wt. of an inorganic filler. In this case, the properties of (B) sericite have 20-55 μm average flake diameter and 20-60 aspect ratio. (C) The inorganic filler is composed of a fibrous filler and a powdery filler in the weight ratio of the fibrous filler/the powdery filler of 40-80/60-20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyarylene sulfide resin composition, and more particularly, to a polyarylene sulfide resin composition useful in the field of precision OA equipment such as optical pickup parts, floppy disk drive (FDD) parts, and hard disk drive parts. About things.

[0002]

2. Description of the Related Art Conventionally, FDD, compact disc (C
D), precision OA such as digital video disk (DVD)
Equipment parts have been manufactured by the metal die-casting method using aluminum, zinc, etc., but due to the increasing needs for cost reduction and weight reduction in recent years, resinization has been studied and is gradually being replaced. In this case, depending on the function of those parts, the resin material has dimensional accuracy and stability in injection molding, moldability (fluidity), product rigidity, environmental resistance (heat resistance, moisture resistance, chemical resistance), difficulty in Flammability is required. For this reason, polyarylene sulfide resin (hereinafter “P”)
Engineering plastics such as AS ") are often used. However, in recent years, a resonance problem has occurred due to a higher recording capacity and a thinner product shape, and rigidity equivalent to that of metal is required. Therefore, a plate-like filler such as mica and a filler such as carbon fiber are blended to increase rigidity and elasticity.

[0003]

Of these fillers,
Plate-like fillers are often used to improve the modulus of elasticity and ensure dimensional accuracy such as warpage. For example, JP-A-57-63355 discloses PAS with gold mica (phylogophite mica). A resin composition containing
No. 6 discloses resin compositions in which white mica (muscovite mica) is blended with PAS. However, these gold mica and white mica have a large aspect ratio.
Since it is 30 to 100, it is oriented in the flow direction during injection molding,
Although the coefficient of linear expansion in the flow direction (MD) and the direction perpendicular to the flow direction (TD) both decrease, there is a disadvantage that the coefficient of linear expansion in the thickness direction increases. The magnitude of the anisotropy of the coefficient of linear expansion causes a large dimensional variation in a certain direction under a high-temperature environment, resulting in unstable operation characteristics.

The present inventors have solved the problems of the prior art, and have high rigidity, high elastic modulus and fluidity, and have anisotropy of the coefficient of linear expansion and shrinkage in the thickness direction of the molded product. As a result of intensive studies to obtain a relaxed resin composition, when sericite is blended with a specific proportion of inorganic filler in a PAS, the linear expansion coefficient while maintaining a high elasticity even if the aspect ratio is slightly large, The present inventors have found that the anisotropy of the shrinkage ratio is reduced, and have reached the present invention.

[0005]

That is, the present invention relates to (A) 100 parts by weight of a polyarylene sulfide resin and (B)
5-200 parts by weight of sericite and (C) inorganic filler 10-
It is intended to provide a polyarylene sulfide resin composition containing 500 parts by weight.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The (A) polyarylene sulfide resin (PAS) in the present invention is not particularly limited as long as it mainly has an arylene sulfide group as a repeating unit, but polyphenylene sulfide is preferable.

As polyphenylene sulfide, for example, the reaction of a halogen-substituted aromatic compound with an alkali sulfide as disclosed in JP-B-44-27671 and JP-B-45-3368 is disclosed in JP-B-45-27255. The reaction of condensing an aromatic compound with sulfur chloride by a Lewis acid catalyst as disclosed, or U.S. Pat.
A polymer synthesized by a condensation reaction or the like in the presence of an alkali catalyst or a copper salt of a thiophenol, as disclosed in JP-A-2003-207, containing at least 80 mol% of a p-phenylene sulfide group as a repeating unit. Can be suitably used. Further, as a repeating unit derived from a copolymer component, m-phenylene sulfide group,
o-phenylene sulfide group, substituted phenylene sulfide group, p, p′-biphenylene sulfone sulfide group, p, p′-biphenylene sulfide group, p,
p′-biphenylene ether sulfide group, p, p ′
Those containing less than 20 mol% of an arylene sulfide group such as a biphenylene carbonyl sulfide group, a naphthalene sulfide group or a trifunctional phenyl sulfide group in a range that does not adversely affect the crystallinity of the polymer can also be used.

[0008] These resins are nearly white immediately after the reaction such as condensation as described above, and some of them have low molecular weight and low viscosity, but are oxidized by heating below the melting point in air. It is used by being branched or cross-linked, or branched or cross-linked by a branching agent in the step of the condensation reaction to increase the molecular weight, and changed to a melt viscosity suitable for injection molding or the like. In some cases, a sufficiently high-molecular-weight and high-viscosity linear resin is obtained in the condensation reaction step, and this resin can also be used. Since polyphenylene sulfide is commercially available in various grades, polyphenylene sulfide is easily available, and is economically and suitably suitable. These can be used alone or in combination.

In the resin composition of the present invention, a small amount of a thermoplastic resin other than PAS can be used in combination, and any thermoplastic resin stable at a high temperature can be used. For example, olefin polymers, polyethylene terephthalate, polybutylene terephthalate, aromatic polyester polymers such as aromatic dicarboxylic acids and diols or oxycarboxylic acids such as wholly aromatic polyesters, polyamide polymers, polycarbonate, ABS, polyphenylene oxide, poly Examples include alkyl acrylate, polyacetal, polysulfone, polyethersulfone, polyetherimide, polyetherketone, and fluororesin. These thermoplastic resins can be used as a mixture of two or more kinds.

[0010] Among them, as a polyolefin polymer,
Ethylene-based copolymer or its graft copolymer, for example, a copolymer of ethylene with α, β-unsaturated fatty acid or its alkyl ester or glycidyl ester, or a graft copolymer further grafted with a vinyl-based polymer, etc. Are particularly preferred as auxiliary components.

[0011] The sericite (B) used in the present invention is a dioctahedral mica which is called silk mica, shows a white to pale red color, and has a silky luster. It is also called hydrated muscovite and has properties similar to white mica, but the content of SiO ₂ is large for the chemical composition obtained from the ideal chemical formula of white mica,
The content of Al ₂ O ₃ is low. In addition, potassium is low and water is high. Cations such as Mg and Fe ³⁺ substituted for Al in the octahedral sheet are also observed, and are particularly characterized by a decrease in interlayer cations and the presence of H ₂ O ⁻ . Furthermore, a difference is recognized in the optical properties.

The properties of sericite are as follows.
It is appropriate that the aspect ratio is 20 to 60 at an average flake diameter of 25 to 55 μm and the aspect ratio is 20 to 60 μm.
Preferably it is 40-60. If the average flake diameter is less than 20 μm, adjustment becomes difficult, and if it exceeds 55 μm, the anisotropy of the coefficient of linear expansion becomes large. Similarly, when the aspect ratio is less than 20, it is difficult to adjust the aspect ratio. When the aspect ratio exceeds 60, the anisotropy of the linear expansion coefficient becomes large.

The amount of sericite used is suitably from 5 to 200 parts by weight, particularly preferably from 20 to 100 parts by weight, per 100 parts by weight of PAS.

As the inorganic filler (C) used in the present invention, a fibrous or powdery inorganic filler can be selected according to the purpose. Examples of the fibrous filler include glass fibers, carbon fibers, graphite fibers, wollastonite, or various whiskers such as zinc oxide whiskers, aluminum borate whiskers, potassium titanate whiskers, silicon carbide whiskers, sapphire whiskers, and silicon carbide whiskers. In addition, metal wires such as metal fibers, ceramic fibers, and copper wires, steel wires, and stainless steel wires can be used. Also,
Heat-resistant inorganic composite fibers such as so-called boron fibers or silicon carbide fibers obtained by depositing boron or silicon carbide on carbon fibers,
Heat-resistant organic fibers such as aromatic aramid fibers can also be used.

Among them, carbon fiber is particularly generally used for imparting high rigidity, and is made of a fire-resistant, carbon fiber fired from cellulose fiber, acrylic fiber, lignin fiber, petroleum-based special pitch, or the like. Various types such as graphite and graphite can be used. Carbon fiber length 0.3 ~ 10
mm is preferred, and the use of this length allows the resulting composition to contain 0.1-0.8 mm long carbon fibers, which allows higher mechanical strength to be obtained. The fiber diameter of the carbon fibers is suitably about 5 to about 15 μm, and usually a converged 100 to 1000 carbon fibers is convenient for handling.

Glass fiber is a fibrous filler that is economically and economically suitable, and any of alkali-containing glass fibers, low-alkali glass fibers, and alkali-free glass fibers can be used. The glass fiber has a length of 0.1 to 1 mm in the polyarylene sulfide resin composition, and in particular, has a length of 0.2 to 1 mm.
Particularly preferred is 0.5 mm. The glass fiber often breaks during kneading with the resin, and the size of the glass fiber used for kneading is usually preferably 2 to 5 mm in length. The fiber diameter of the glass fiber is usually 5 to 20 μm, particularly preferably 7 to 15 μm. If the fiber diameter exceeds 20 μm, kneading with the resin becomes difficult, and this is not preferable in terms of the performance of the composition.

The form of the glass fiber is not particularly limited, and may be, for example, roving, chop strand, milled fiber or the like. In using the glass fiber, the glass fiber may be subjected to a surface treatment such as a borane treatment, a silane treatment, a titanate treatment, and an epoxy treatment.

On the other hand, powdery fillers include carbon black, graphite, Ketjen black, silica, quartz powder,
Glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, diatomaceous earth, silicates such as wollastonite, oxides of metals such as iron oxide, titanium oxide, alumina, calcium carbonate, Examples thereof include metal carbonates such as magnesium carbonate, metal sulfates such as calcium sulfate and barium sulfate, silicon carbide, silicon nitride, boron nitride, and various metal powders.

The amount of the inorganic filler to be used is suitably from 10 to 500 parts by weight, particularly preferably from 20 to 200 parts by weight, per 100 parts by weight of PAS. If less than 10 parts by weight, the strengthening effect is small, 500
If the amount exceeds the weight part, the fluidity at the time of molding becomes poor.

As described above, the fibrous filler and the powdery filler may be appropriately selected and used depending on the purpose.
The fibrous filler and the powdery filler are mixed in a weight ratio of fibrous filler / powder filler of 40 to 80/60 to 20, particularly preferably 45 to 75 /.
It is preferable to use them together at a ratio of 55 to 25 in view of mechanical strength and dimensional stability during molding. The mechanical strength is low only with the powdered filler.

The resin composition of the present invention may contain a releasing agent, a lubricant, a crystal nucleating agent, a coupling agent, a compatibilizer,
UV absorbers, colorants and other usual additives can be added.

The resin composition of the present invention can be prepared by mixing or kneading a predetermined ratio of a polyarylene sulfide resin, sericite and an inorganic filler. Mixing and kneading can be performed according to a known method. For example, ribbon blenders, tumbler mixers,
The mixture may be melt-kneaded using a mixer such as a Henschel mixer, or may be simultaneously mixed using a Banbury mixer, a screw kneader, or the like. A pellet is formed by kneading, and a molded article is formed using the pellet by various molding methods, usually an injection molding method.

[0023]

EXAMPLES The raw materials used in the examples and comparative examples are collectively shown below. Polyphenylene sulfide resin (PPS): manufactured by Toprene Co., Ltd. T1, T2, T3 Semi-crosslinked type having a melt viscosity of 200 to 1000 poise at a temperature of 300 ° C. and a shearing speed of 1000 sec ^-1 Serisite A: manufactured by Sanshin Mining Co., Ltd. Weight average particle size (flake diameter) 45μm, aspect ratio 40 sericite B: Sanshin Mining Co., Ltd. FS1 Weight average particle size (flake diameter) 25μm, aspect ratio 55 sericite C: Kinsei Matech Co., Ltd. Weight average particle size (flake diameter) 60 μm, aspect ratio 60 Gold mica: 200HK manufactured by Kuraray Co., Ltd. 200HK Weight average particle size (flake diameter) 90 μm, aspect ratio 50 White mica A: Kuraray Co., Ltd.・ 200D weight average particle size (flake diameter) 90μm, aspect ratio 50 white mica B: Kuraray Co., Ltd. ・ 300D weight average particle size ( Lake diameter) 40μm, aspect ratio of 35 glass fiber: Asahi Fiber Glass Co., Ltd. · JAF
T591 Carbon fiber: Toho Rayon Co., Ltd., chopped strand CF HTA-C6-SRS Calcium carbonate: Shiraishi Calcium Co., Ltd., Whiten P30

(Examples 1 to 5) A twin screw extruder (Toshiba Machine Co., Ltd., T
The mixture was melt-kneaded at 330 ° C. using EM35) to obtain pellets. Using a 50-ton injection molding machine (manufactured by Nippon Steel Works), the pellet temperature was 320 ° C and the mold temperature was 50%.
Under the condition of 135 ° C., a flat plate having a length and width of 80 mm and a thickness of 3.2 mm was injection-molded. The following physical property measurement and operating characteristic test were performed on the flat molded product, and the results are shown in Table 2.

Coefficient of linear expansion: A test piece for measurement was cut out from a flat plate-shaped molded product and manufactured by Seiko Denshi Kogyo Co., Ltd.
Using MA120C, the coefficient of linear expansion from room temperature to 60 ° C. was measured in the direction parallel to the flow direction (MD) and the direction perpendicular to the direction (TD) of the resin during injection molding and in the thickness direction. Tensile strength: based on ASTM-D638. Flexural strength and flexural modulus: based on ASTM-D790. High-temperature dimensional displacement: A non-contact depth meter was used to measure the displacement in the thickness direction when the room temperature (23 ° C.) was set to zero while the flat molded product was kept at 70 ° C. in a thermostat. Operating characteristics: Apart from a flat molded product, a CD pickup component was injection molded and evaluated on a real machine (high temperature environment test at 70 ° C.).

Comparative Examples 1 to 3 Example 1 except that sericite A was changed to gold mica, white mica A or white mica B
And the results are shown in Table 2.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

The polyarylene sulfide resin composition of the present invention has a high rigidity, a high elastic modulus and a fluidity, and the anisotropy of the coefficient of linear expansion and shrinkage in the thickness direction of the molded product is reduced. It can be molded into a molded product having high dimensional accuracy, and it is possible to manufacture an optical pickup component having improved temperature characteristics such as deviation of an optical spot. In the case of sericite, the reason why the anisotropy of the linear expansion coefficient and the contraction rate is reduced even if the aspect ratio is slightly large is not clear, but it is an effect which cannot be expected from the conventional technology.

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Claims (3)

[Claims] 1. A polyarylene sulfide resin
A polyarylene sulfide resin composition comprising (B) 5 to 200 parts by weight of sericite and (C) 10 to 500 parts by weight of an inorganic filler per 100 parts by weight. 2. The polyarylene sulfide resin composition according to claim 1, wherein the properties of (B) sericite have an average flake diameter of 20 to 55 μm and an aspect ratio of 20 to 60. 3. The method according to claim 1, wherein (C) the inorganic filler comprises a fibrous filler and a powdery filler, and the weight ratio of the fibrous filler / the powdery filler is 40-80 / 60-20. The polyarylene sulfide resin composition according to the above.