JPH0578576A - Polyarylene sulfide resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition reduced in the tendency to form burrs and excellent in flow and mechanical properties by mixing a plurality of specified polyarylene sulfide resins with a specified filler in a specified weight ratio. CONSTITUTION:The objective composition is prepared by mixing a thermally crosslinkable polyarylene sulfide resin (A) having a melt flow rate (ASTM D1238-8700 O, 300 deg.C, load of 1.2kg) of 3.5 (g/10min) or below (e.g. T-7, a product of Tohprene Co.) with a polyarylene sulfide resin (B) of a melt flow rate of 150 (g/10min) (e.g. T-1, a product of Tohprene Co.) and a filler (C) (e.g. glass fiber) in an A/B weight ratio of 95/5 to 51/49 and a C/(A+B) weight ratio of 2/98 to 70/30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyarylene sulfide resin, and more particularly to a polyarylene sulfide resin having less burrs during molding and improved fluidity.

[0002]

2. Description of the Related Art In recent years, the fields of application of engineering plastics have expanded more and more, and the applications to the automobile, electric, electronic and mechanical fields have been remarkably increasing. Along with this, users' demands for plastics have been diversified and functionalized, and more excellent heat resistance, flame retardancy, chemical resistance, dimensional stability, mechanical properties, etc. have been demanded. There is.

Polyphenylene sulfide resin (hereinafter PP
A polyarylene sulfide resin represented by S) (hereinafter referred to as PAS) is a known engineering plastic, which has been developed in view of the above requirements and has been used for many applications. That is, P
AS has excellent heat resistance, flame resistance, chemical resistance, dimensional stability,
Mechanical properties and their balance have been evaluated and have been used in many fields.

[0004]

However, when this resin is processed by a molding method typified by injection molding,
Since the melt viscosity is extremely low, burrs tend to be formed, which is a particular problem when performing precision molding. Therefore, the present inventors have conducted various studies for the purpose of increasing the melt viscosity of PAS to reduce burrs. This resulted in a melt flow rate (ASTM D 1238-89 O;
It has been found that the use of PAS having a temperature of 300 ° C. and a load of 1.2 kg) of 3.5 (g / 10 minutes) or less significantly reduces burrs.

However, the PAS having a high viscosity obtained in this manner has too high a viscosity when performing precision molding represented by injection molding, so that the injection pressure is greatly increased, the cylinder temperature, It was found that there are many cases in which the mold is not fully filled even if the mold temperature is raised and a short shot occurs or the mold is damaged. Therefore, it is an object to obtain a PAS with less burr and good fluidity.

[0006]

The present invention solves the above-mentioned problems and is characterized by a melt flow rate (AS).
TM D 1238-89 O; 300 ° C., load 1.2
kg) is 3.5 (g / 10 minutes) or less and a thermally crosslinked polyarylene sulfide resin (A), and 150 (g / 10
Min) or more polyarylene sulfide resin (B)
And (A) / (B) = 95/5 to 51/49 (1) (C) / {(A) + (B)} = 2/98 to 70/30 The polyarylene sulfide resin composition is compounded in a weight ratio of 2).

Each of PAS (A) and (B) used in the present invention contains 70 mol% or more of the repeating unit represented by the structural formula-(-Ar-S-)-(hereinafter Ar is an aryl group). It is a polymer, and its representative substance is PPS containing 70 mol% or more of the repeating unit represented by the structural formula-(-Ph-S-)-(hereinafter Ph is a phenyl group). The PPS preferably used as the PAS in the present invention is
A polymer containing a repeating unit represented by the structural formula-(-Ph-S-)-in an amount of 70 mol% or more, more preferably 80 mol% or more. If the repeating unit is less than 70 mol%, heat resistance is impaired. Therefore, it is not preferable. Further, less than 30 mol% can be composed of a repeating unit having the following structural formula.

[0008]

[Chemical 1]

[0009]

[Chemical 2]

[0010]

[Chemical 3]

[0011]

[Chemical 4]

[0012]

[Chemical 5]

[0013]

[Chemical 6]

[0014]

[Chemical 7]

[0015]

[Chemical 8]

[0016]

[Chemical 9]

In accordance with the present invention, ASTM D 1238-
89 O; 300 ° C., melt flow rate measured under a load of 1.2 kg, thermal crosslinkable PAS (A) of 3.5 (g / 10 minutes) or less and PAS of 150 (g / 10 minutes) or more
Two or more types of PAS of (B) are used. Thermal cross-linked PA
Melt flow rate of S (A) is 3.5 (g / 10 minutes)
If it exceeds, the burr will not be improved. On the other hand, when the melt flow rate of PAS (B) is less than 150 (g / 10 minutes), the fluidity of the resin composition is not improved.

PPS is generally obtained by a production method represented by JP-B-45-3368. The polymer obtained here is polymerized to have a high molecular weight by heating in an oxygen atmosphere after polymerization or by adding a crosslinking agent such as peroxide and heating, and used as PAS (A) of the present invention. You can The PAS (B) used in the present invention has a melt flow rate of 150 (g / 10) obtained by the production method typified by the above-mentioned JP-B-45-3368 and JP-B-52-12240.
Min) or more PAS.

For the purpose of controlling the degree of crosslinking of PAS (A),
Ordinary peroxide-based cross-linking agent and JP-A-59-13165
0, a crosslinking accelerator such as a thiophosphinic acid metal salt, or JP-A-58-204045.
It is also possible to add a crosslinking inhibitor such as dialkyltin dicarboxylate or aminotriazole described in JP-A-58-204046.

In the present invention, PAS (A) and PAS
(B) and (B) are mixed in a weight ratio of formula (1). PAS (B)
If the ratio is too large, the melt viscosity will be reduced more than necessary, and burr reduction will not be achieved as a whole, which is not preferable. Moreover, the low viscosity P used as PAS (B) in the present invention
Since AS generally has a low degree of polymerization, mechanical properties, especially toughness,
Since the impact resistance may be inferior in some cases, if the ratio is increased, the original mechanical properties of PAS (A) cannot be utilized. Also,
Conversely, if the PAS (B) is low, the melt viscosity will be too high and
It is not preferable because the effect of (B) is small and a problem remains in moldability. Therefore, the weight ratio of PAS (A) and PAS (B) is preferably 90/10 to 60/40, more preferably 90/10 to 70/30.

When PAS (B) was blended with PAS (A), it was expected that the melt viscosity would be lowered and accordingly more burrs would be produced. However, at a particular blending ratio as in the present invention, there is little burring. It is possible to improve the flowability, which is a drawback, while maintaining the characteristics of PAS (A). It is considered that this is because the molecular weight distribution of PAS, the crystallization rate, etc. act intricately in the mechanism of burr formation.

In the resin composition of the present invention, a resin portion ((A) + (B)) is provided with a reinforcing filler (C) for a resin represented by glass fiber, (C) / {(A). + (B)} = 2
/ 98 to 70/30, preferably 10/90 to 50/5
Although it is possible to improve the rigidity and the like by adding it in a weight ratio of 0, if the reinforcing filler exceeds this range, the surface of the molded product becomes rough and the physical properties become brittle, which is not preferable.

Suitable reinforcing fillers include glass fibers,
Carbon fiber, metal fiber, aramid fiber, potassium titanate, asbestos, silicon carbide, ceramic, silicon nitride, barium sulfate, calcium sulfate, kaolin, clay, pyrophyllite, bentonite, sericite, zeolite, mica, mica, nephelinesh Knight, talc, atarupulgite, wollastonite, PMF,
Reinforcement of ferrite, calcium silicate, calcium carbonate, magnesium carbonate, dolomite, zinc oxide, titanium oxide, magnesium oxide, iron oxide, molybdenum disulfide, graphite, gypsum, glass beads, glass powder, glass balloon, quartz, quartz glass, etc. Fillers may be mentioned, which may be hollow. Further, two or more kinds of these reinforcing fillers can be used in combination, and if necessary, they can be used after being pretreated with a coupling agent such as a silane-based or titanium-based coupling agent. Preferred is glass fiber.

The resin composition of the present invention also includes a plasticizer such as an aromatic hydroxy derivative such as 2-ethylhexyl-p-hydroxybenzoate, a sulfonic acid amide such as benzenesulfonamide, or a small amount of a release agent. Further, a coupling agent, a colorant, a lubricant, a heat resistance stabilizer, a weather resistance stabilizer, a foaming agent, a rust preventive, a flame retardant and the like may be added.

The resin composition of the present invention can be adjusted by various known methods. For example, after uniformly mixing the raw materials with a mixer such as a tumbler or a Henschel mixer,
There is a method in which pellets are prepared after being melt-kneaded by being supplied to a uniaxial or biaxial extruder or the like. The reinforcing filler can be mixed in the same manner, but when an extruder is used, side feeding is preferably performed from the middle of the extruder to prevent the reinforcing filler from being destroyed. The melt-kneading temperature is preferably 280 to 340 ° C, and PAS is less than 280 ° C.
In some cases, the melting of the resin may become insufficient, and if it exceeds 340 ° C., the resin may be deteriorated by heat and gelation may occur.

[0026]

The present invention will be described in more detail with reference to the following examples, which should not be construed as limiting the present invention. The evaluation of burrs at the time of injection molding according to the present invention was performed using a length of 1
Using a die for a strip test piece having a width of 25 mm, a width of 13 mm, and a thickness of 3.2 mm, burrs formed in an air vent portion having a clearance of 30 μm were measured. That is, the minimum injection pressure at which the resin is fully filled in the mold and the burr length in the direction perpendicular to the end surface of the molded product at that time were measured, and the average values were compared.

The Izod impact test and the bending test in the present invention are ASTM D-256 and D-7, respectively.
According to 90.

[0028]

Examples 1 to 4 Melt flow rate (ASTM D1
238-89 O) is 1.6g / 10min thermal crosslinked PP
S powder (T-9 manufactured by Topren Co., Ltd .; hereinafter referred to as PPS1) and melt flow rate (ASTM D1238-
89 O) and 180 g / 10 min of PPS powder (T-1 manufactured by Topren Co., Ltd .; hereinafter referred to as PPS3) were mixed with a Henschel mixer in a nitrogen atmosphere at a compounding ratio shown in Table 1 for 5 minutes, and then plastic. Engineering Research Institute Co., Ltd. "BT-
It was pelletized with a 40 "twin-screw extruder at a cylinder temperature of 290 ° C. The glass fiber was side-fed from the middle of the extruder. The glass fiber used at this time was a commercially available diameter of 13 µm and a length of 3 mm. The obtained pellets were heated at a cylinder temperature of 270 ° C. in a hopper.
The central part was set to 300 ° C. and the tip part was set to 310 ° C., and a test piece was obtained by an ordinary injection molding method to measure various physical properties. The obtained results are shown in Table 1.

[0029]

Example 5 Melt Flow Rate (ASTM D123
8-89 O) is 3.2 g / 10 minutes in thermal crosslinkable PPS powder (T-7 manufactured by Topren Co., Ltd .; hereinafter referred to as PPS2).
And PPS3 were mixed with a Henschel mixer in a nitrogen atmosphere at a compounding ratio shown in Table 1 for 5 minutes, and then pelletized with a "BT-40" twin-screw extruder manufactured by Plastic Engineering Laboratory Co., Ltd. at a cylinder temperature of 290 ° C. .. The glass fiber was side-fed from the middle of the extruder. Further, the glass fiber used at this time has a diameter of 13 μm and a length of 3 which are commercially available.
mm. Cylinder temperature of the obtained pellets is 270 ° C. in the hopper, 300 ° C. in the center, and 310 in the tip.
The test piece was obtained by a usual injection molding method at various temperatures, and various physical properties were measured. The obtained results are shown in Table 1.

[0030]

[Comparative Examples 1 to 4] PPS1, PPS2, PPS3, PPS powder having a melt flow rate (O of ASTM D1238-89) of 3.7 g / 10 min (T, manufactured by Topren Co., Ltd.).
-4; hereinafter referred to as PPS4) was pelletized with a "BT-40" twin-screw extruder manufactured by Plastic Engineering Laboratory Co., Ltd. at a cylinder temperature of 290 ° C. The glass fiber was side-fed from the middle of the extruder. The glass fiber used at this time has a diameter of 13 μm and a length of 3 mm, which is commercially available. Cylinder temperature of the obtained pellets is 270 ° C. at the hopper, 300 ° C. at the center, and 31 at the tip.
The test piece was set at 0 ° C., and a test piece was obtained by a usual injection molding method to measure various physical properties. The obtained results are shown in Table 1.

[0031]

[Table 1]

[0032]

INDUSTRIAL APPLICABILITY The resin composition of the present invention is a molding material which has reduced burr at the time of molding and improved fluidity at that time and is highly practical as an engineering plastic having excellent mechanical properties.

Continuation of the front page (72) Inventor Kentaro Kumooka 3-13-1, Shiodori, Kurashiki City, Okayama Prefecture Asahi Kasei Corporation

Claims (1)

[Claims] 1. A melt flow rate (ASTM D 1
238-89 O; 300 ° C., load 1.2 kg)
The heat-crosslinkable polyarylene sulfide resin (A) having 3.5 (g / 10 minutes) or less, the polyarylene sulfide resin (B) having 150 (g / 10 minutes) or more, and the filler (C). , (A) / (B) = 95/5 to 51/49 (1) (C) / {(A) + (B)} = 2/98 to 70/30 (2) A polyarylene sulfide resin composition comprising: