JP2759658B2 - Polyarylene sulfide resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a polyarylene sulfide resin composition having improved moldability without substantially reducing physical properties such as strength and heat resistance. The polyarylene sulfide resin composition of the present invention can be effectively used as a material for various molded articles, particularly mechanical and electrical parts.

[Problems to be Solved by Conventional Techniques and Inventions] Polyarylene sulfide (hereinafter sometimes abbreviated as PAS) resin is excellent in heat resistance, chemical resistance, electrical and mechanical properties, dimensional stability, etc. Used as engineering plastic. However, when molding this resin at a high temperature, the resin is decomposed and colored, and it is not possible to heat the resin to a certain temperature or higher. However, due to this, burrs are often generated, which is a problem. This is especially true of the recently developed high molecular weight, substantially linear PAS with excellent mechanical strength.
It is becoming more important in the case of resins.

Therefore, an attempt to improve the moldability by adding ordinary polystyrene to the PAS resin has been proposed (Japanese Patent Publication No. 53-13469). According to this invention, although the molding temperature can be lowered, the strength and heat resistance are greatly reduced, and the characteristics of the PAS resin cannot be utilized.

Therefore, there is a demand to improve the moldability while maintaining the excellent characteristics of PAS resin such as strength and heat resistance, especially for a filler compound composition, which tends to have insufficient moldability. Have been.

[Means for Solving the Problems] The inventors of the present application have conducted intensive studies to solve such problems, and as a result, by adding a small amount of polystyrene having a specific structure to PAS resin, strength, heat resistance, etc. The present inventors have found that a resin composition having almost no deterioration in physical properties and having good moldability can be obtained, and the present invention has been completed based on this finding.

That is, the present invention provides a polyarylene sulfide resin composition containing a styrene-based polymer having a syndiotactic structure in an amount of 1% by weight or more and less than 30% by weight, with the entire composition as 100%. It is intended to provide a polyarylene sulfide resin composition comprising 100 parts by weight of the composition and 1 to 500 parts by weight of a filler.

In the present invention, a polyarylene sulfide resin (PAS resin) is used as a main component.

Here, as the PAS resin, for example, the formula And polyphenylene sulfide having a repeating unit represented by the following formula:

In the present invention, the polyphenylene sulfide has 70% by mole or more, preferably 80% by mole or more of paraphenylene groups as a whole, and a solution viscosity ηinh obtained at 206 ° C. by adding 0.4 g of solute to 100 ml of solvent α-chloronaphthalene is added. 0.05dl
/ g or more, preferably 0.1 to 0.8 dl / g is suitably used.

The polyphenylene sulfide may be a copolymer of not more than 30 mol% of a metaphenylene group or an orthophenylene group in addition to a paraphenylene group. As these copolymers, block copolymers are preferred.

Further equations (Wherein, R represents an alkyl group having 1 to 6 carbon atoms, and n represents 1 to 4).

These PAS resins may be substantially linear, cross-linked by a branching agent or heat, or a mixture thereof.

Next, in the present invention, a styrene-based polymer having a syndiotactic structure (hereinafter may be simply abbreviated as SPS polymer) is mainly used as a component to be mixed with the PAS resin.

The predominantly syndiotactic structure of the styrenic polymer is defined as having a stereochemical structure that is predominantly a syndiotactic structure, that is, a phenyl group or a substituted phenyl group, which is a side chain to a main chain formed from carbon-carbon bonds, is alternated. Has a steric structure that is located in the opposite direction to that of the nuclear magnetic resonance ( ¹³ C-NMR) method using isotope carbon.
Method). Tacticity measured by the ¹³ C-NMR method can be represented by the abundance ratio of a plurality of continuous structural units, for example, a dyad for two, a triad for three, and a pentad for five. However, the styrenic polymer having a predominantly syndiotactic structure as referred to in the present invention is usually 75% or more, preferably 85% or more in a dyad, or 30% or more, preferably 50% in a pentad (racemic pentad). Polystyrene, poly (alkyl styrene), poly (halogenated styrene), poly (alkoxy styrene), poly (vinyl benzoate) having the above syndiotacticity and mixtures thereof, or copolymers containing these as main components Refers to coalescence. Here, poly (alkylstyrene) includes poly (methylstyrene), poly (ethylstyrene), poly (isopropylstyrene),
Examples include poly (t-butylstyrene), and examples of poly (halogenated styrene) include poly (chlorostyrene), poly (bromostyrene), and poly (fluorostyrene). Also, as poly (alkoxystyrene),
Poly (methoxystyrene), poly (ethoxystyrene)
and so on. Of these, particularly preferred styrene polymers include polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), poly (pt-butylstyrene), poly (p-chlorostyrene), and poly (p-chlorostyrene). m-chlorostyrene), poly (p-fluorostyrene), and a copolymer of styrene and p-methylstyrene.

The molecular weight of the SPS polymer used in the present invention is not limited, but preferably has a weight average molecular weight of 10,000 or more, and most preferably 50,000 or more. Here, when the weight average molecular weight is less than 10,000, the heat resistance and mechanical strength are not sufficient, and no sufficient improvement is recognized even after blending. Further, the molecular weight distribution is not limited in its width, and various molecular weight distributions can be applied.

The SPS polymer has a melting point of, for example, 160 to 310 ° C.
However, the heat resistance is remarkably superior to that of the conventional styrene polymer having an atactic structure.

Such an SPS polymer is prepared, for example, by using a titanium compound and a condensation product of water and a trialkylaluminum as a catalyst in an inert hydrocarbon solvent or in the absence of a solvent, using a styrene-based monomer (SPS polymer). (Corresponding monomer) by polymerization (Japanese Patent Laid-Open No. 62-1877).
08 publication).

The polyarylene sulfide resin composition of the present invention basically comprises the PAS resin and the SPS polymer as described above.
The content is not less than 30% by weight and preferably not less than 30% by weight, preferably 1 to 28% by weight. Here, when the content of the SPS polymer is 30% by weight or more, the heat distortion temperature decreases, and the flame retardancy and the like decrease. On the other hand, if the content of the SPS polymer is too small, especially if it is less than 1% by weight, the effect of improving fluidity and burrs is not sufficient, which is not preferable.

Further, a filler can be added to the polyarylene sulfide resin composition of the present invention.

Here, it does not matter whether the filler is fibrous or powdery. Examples of the fibrous filler include various fibers made of glass, asbestos, silica, silica-alumina, silicon nitride, silicon carbide, potassium titanate, polyamide, polyimide, carbon, and the like. preferable. Here, as the shape of the glass fiber, there are a bundle cut shape, a short fiber, and a filament shape, but it is preferably a bundle cut shape,
Those having a length of 0.05 mm to 13 mm and a fiber diameter of 5 to 15 μm, particularly those treated with a silane-based or titanate-based coupling agent are preferred. The carbon fiber is preferably a chopped fine bar type or a milled fiber type, and preferably has a length of 0.05 to 20 mm and a diameter of 3 to 15 μm.

Examples of the powdery filler include silica, talc, clay, mica, powdered glass, zeolite, bentonite, montmorillonite, carbon black, titanium oxide, silicon carbide, calcium carbonate, calcium sulfate,
Barium carbonate, magnesium carbonate, magnesium sulfate,
Examples include barium sulfate, oxysulfate, tin oxide, alumina, kaolin, and metal powder.

In the present invention, among the various fillers as described above,
It is preferable to use a combination of an inorganic filler, particularly a fibrous inorganic filler, for example, a fiber such as glass fiber or glass fiber and a powdery filler.

The filler is 1 to 500 parts by weight based on 100 parts by weight of the polyarylene sulfide resin composition containing the SPS polymer as described above in a proportion of 1% by weight or more and less than 30% by weight, based on 100% of the entire composition. It is used in a proportion of 5 parts by weight, preferably 5 to 300 parts by weight. Here, if the compounding ratio of the filler is less than 1 part by weight, the effect of improving the rigidity and the like by mixing the filler cannot be expected. On the other hand, the mixing ratio of the filler is 50
Exceeding 0 parts by weight is not preferred in terms of uniform dispersion and moldability. In addition, an effect that is commensurate with the blending amount cannot be expected.

The polyarylene sulfide resin composition of the present invention is a combination of the above-mentioned PAS resin and the SPS polymer or a combination thereof with a filler, and further, if necessary, various additives such as a nucleating agent, an antioxidant, Plasticizers, compatibilizers, lubricants, coloring agents, antistatic agents and the like can be added, and it is particularly desirable to add nucleating agents, antioxidants and plasticizers.

Although various antioxidants are used, a phosphorus antioxidant and a phenol antioxidant are particularly preferable.

The composition of the present invention may be uniformly prepared by kneading the above-mentioned components by a usual method using a kneader, a mixing roll, an extruder, a mixer, or the like, or by solution blending or the like.

The composition thus obtained can be made into various molded articles by injection molding, extrusion molding or the like.

[Examples] Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited thereto without departing from the scope of the present invention.

Examples 1 to 4 and Comparative Examples 1 to 4 The components shown in Table 1 were blended at a predetermined ratio, and then melt-kneaded and extruded using an extruder to obtain pellets. Using these pellets, a strip-shaped molded product (127 mm
× 12.7 mm × 3.2 mm) was obtained by injection molding. First measurement results of minimum filling pressure, burr length and various physical properties during molding
It is shown in the table.

* 1 PAS resin PPS-1: linear polyphenylene sulfide, η _inh = 0.24
dl / g PPS-2: cured cross-linked polyphenylene sulfide, η _inh =
0.18 dl / g * 2 SPS polymer SPS-1: Styrene polymer mainly having a syndiotactic structure, _W = 400,000 SPS-2: Styrene polymer mainly having a syndiotactic structure, _W = 240,000 The SPS polymer has a melting point of 270 ° C. and a syndiotacticity of 90% or more.

* 3 GF (glass fiber) manufactured by Asahi Fiberglass Co., Ltd., 03 MA 404, fiber diameter = 13 μm, fiber length = 3 mm * 4 Melt viscosity The melt viscosity at 300 ° C when the apparent shear rate is 200 sec ^-1 is A Assuming that the melt viscosity at 1000 sec ^-1 is B, these melt viscosities are shown in Table 1 in the form of A / B, and the ratio is shown in parentheses. In particular, A / B
Is high, the melt viscosity is low at a high shear rate, indicating good moldability.

* 5 using spiral flow mold length 1 mm × 10 mm cross section, 320 ° C., spiral flow length * 6 minimum pressure required minimum filling pressure mold completely filling when conducted under the conditions of 800 kg / cm ² * 7 Burr length Indicates the length of the burr at the tip of a strip-shaped molded product.

* 8 Thermal distortion temperature (thermal deformation temperature) 264 psi (according to ASTM D648) * 9 Flexural strength conforming to ASTM D790 * 10 Flexural modulus conforming to ASTM D790 * 11 Izod impact strength conforming to ASTM D256 [Effects of the Invention] ] As described above, the polyarylene sulfide resin composition of the present invention has the inherent heat resistance of the polyarylene sulfide resin,
The moldability is improved without substantially reducing the physical properties such as impact resistance, strength, and rigidity. This composition does not require a high molding temperature, suppresses the decomposition of the resin, does not cause coloring due to it, and can reduce the injection molding pressure, so that the occurrence of burrs can be reduced, It can be suitably used for various molded articles, particularly materials for injection molding such as mechanical and electronic parts.

In particular, the present invention is suitable for a composition using a substantially linear PSP resin having a relatively high molecular weight, high strength, and high whiteness.

Claims (2)

(57) [Claims] 1. A polyarylene sulfide resin composition containing a styrene-based polymer having a syndiotactic structure in an amount of 1% by weight or more and less than 30% by weight based on 100% of the total composition. 2. A polyarylene sulfide resin composition comprising 100 parts by weight of the composition according to claim 1 and 1 to 500 parts by weight of a filler.