JP2876608B2 - Polyphenylene sulfide resin molding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a highly practical glass having excellent dimensional stability and appearance of a molded product and greatly improved toughness such as bending strength and impact strength. The present invention relates to a reinforced polyphenylene sulfide resin molding material.

(Prior art) Polyphenylene sulfide resin (hereinafter referred to as PPS resin) has the advantages of excellent heat resistance and chemical resistance,
PPS resin alone has low elongation, is brittle, and has the disadvantage that it cannot be used as a molding material unless reinforced with glass fiber.

Therefore, the glass-reinforced PPS resin molding material has a PPS resin
70% by weight and 30 to 50 micron diameter glass fiber 30 to 50
What is manufactured by mixing and kneading mainly by a twin-screw extruder using the weight% as a main raw material occupies the mainstream of the market.

By the way, in order to maximize the reinforcing effect of glass fiber with glass fiber-containing PPS resin molding material, it is necessary to consider the state of glass fiber in the molding material obtained by uniformly mixing and kneading with an extruder . That is, when comparing PPS resin molding materials having the same composition ratio of PPS resin and glass fiber, the difference in glass fiber length distribution in the molding material greatly affects notched Izod impact strength, bending strength, etc. of the molded product. However, the relationship between the glass fiber length distribution in the glass-reinforced PPS resin molding material and the physical properties has not yet been studied in detail.

For example, JP-A-53-98356 discloses that PPS resin is 55 to 25% by weight and glass fiber is 45 to 75% by weight and the total ratio of both is 80 to 80%.
The glass fiber length distribution in the glass reinforced PPS resin molding material is up to 100% by weight, and the ratio of glass fiber of 150 microns or less is specified as 10 to 65% by weight, but based on the detailed glass fiber length distribution. No supporting data is given.

In Example 1 and Comparative Example 1 of JP-A-57-23655, the glass fiber length distribution for 60% by weight of PPS resin and 40% by weight of glass fiber is described. The glass fiber length distribution of the strength molded test piece is
In Example 1 using a glass fiber having a diameter of 10 microns, the ratio (L / L) of the glass fiber length (L) to the glass fiber diameter (D) was used.
D) In other words, the average aspect ratio is 38, that is, the average aspect ratio is 36, the glass fiber weight of 300 microns or less is 26% by weight of the total glass fiber weight, and the comparative example 1 using the glass fiber having a diameter of 13 microns is 38 The glass fiber weight of 300 microns or less is 17% by weight of the total glass fiber weight and both are
The average aspect ratio of the glass fiber length distribution of the molded test article is very large, and the glass fiber weight of 300 μm or less is very small as 26% by weight or less of the total glass fiber weight. It has become.

However, according to the findings of the present inventors, it has been found that when the aspect ratio exceeds 30, as described above, defects such as warpage, sink marks, and a roughened surface occur in the molded product.

(Problems to be Solved by the Invention) Since the present commercially available glass-reinforced PPS resin material does not provide satisfactory toughness, glass-reinforced PPS resin has not been obtained.
As a result of a detailed study of the relationship between the toughness of the resin molded product and the glass fiber length distribution of the molded product, and other factors, it was found that one of the main factors for improving the toughness is the glass fiber length distribution of the molding material. As a result, the present invention has finally been completed.

(Means for Solving the Problems) That is, the present invention relates to a polyphenylene sulfide resin molding material containing glass fiber, wherein the glass fiber has a fiber length of 25 μm or more and 150 μm or less, which is less than 15% by weight of all glass fibers, and Fiber length 25μm or more 300μ
m or less of glass fiber is 35 to 60% by weight of the total glass fiber, and the average aspect ratio of the glass fiber in the molding material is 17%.
A polyphenylene sulfide resin molding material characterized by having a molecular weight of up to 30.

Melt viscosity of PPS resin used in the present invention (300 ° C in elevated flow tester, preheating time 360 seconds, load 10
(kgf, measured with a die having a diameter of 1 mm and a length of 10 mm) is preferable because the glass fiber is less likely to be damaged during compounding of the twin-screw extruder. However, PPS resin with low melt viscosity and low molecular weight has low glass breakage,
Since the strength of the S resin itself is weak, the effect of improving toughness cannot be expected much. Conversely, a PPS resin having a high melt viscosity has a large degree of glass breakage, so that the effect of improving toughness cannot be expected much. Therefore, in the present invention, those having a linear high molecular weight of about 1000 to 2000 poise are preferred.

Next, as the glass fiber blended in the present invention, commercially available glass fibers having a diameter of 9 to 13 microns can be used.

Glass fibers for PPS resin among commercial glass manufacturers have almost the same basic physical properties such as tensile strength, bending strength and impact strength.The effect of the glass fiber diameter on the basic physical properties is 13 μm. 11 microns is slightly better, but not much different.

Next, among the compounding conditions used for obtaining the material of the present invention, the most important thing is to control the glass fiber length distribution. That is, as the screw rotation speed increases, the glass breakage degree increases, and as the extrusion rate increases, the glass breakage degree tends to decrease.Therefore, the screw element selection and combination technology has excellent toughness. This means that the glass fiber length distribution can be determined.

Therefore, the present inventors have studied the screw element form selection of the glass fiber kneading section, a combination experiment, and conducted a kneading force with a large feed amount, a kneading force with a large feed amount, a screw with a large kneading force with a small feed amount. The result showed that the combination of elements was the most suitable for grinding, dispersing, and mixing glass fibers.

Specifically, as a method for obtaining the material of the present invention, first, when the PPS resin is supplied to the extruder, the cylinder temperature of the molten portion is about 28 ° C.
It is preferable to supply the glass fiber at a stage where the temperature is 0 to 300 ° C. and the glass fiber is completely melted. The cylinder temperature of the glass fiber supply section is preferably about 290 ° C. or higher. In the present invention, after the glass fiber is supplied, the kneading disc and the reverse screw are used in combination at a ratio of 1: 1 to 3: 1, preferably 1: 2, with a positive action: reverse action, and a screw rotation speed (rpm) ( S) and the throughput (kg / hr) (Q) are such that Q / S is 0.15 or more, preferably 0.20
As described above, S is desirably in the range of 100 to 200.

The glass fiber in the material of the present invention obtained by the above method has a glass fiber length of 25 μm or more and 150 μm or less of less than 15% by weight of the whole glass fiber, and more preferably 25 μm or more and 30 μm or less.
The glass fiber length of 0 μm or less is 35 to 6
0% by weight, and the average aspect ratio of the glass fibers in the molding material is 17 to 30, preferably 20 to 25. Outside of the above range, the toughness is extremely low, and the dimensional stability and appearance are unfavorably deteriorated.

(Examples) Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited thereto.

Examples 1 and 2 PPS resin powder (T-3, T-3, melt viscosity 100)
0 poise) 60% by weight and glass fiber with different diameter 40% by weight
Pellets obtained by mixing and kneading (glass lengths are all 3 mm) in the same direction twin-screw extruder under the extrusion conditions that maximize the toughness, and pellets were obtained. The cylinder temperature was 320 using an NN-75 screw type injection molding machine manufactured by Shinyu Iron Works. ASTM D-638 No. 1 tensile test specimen, D-790 bending test specimen, and ASTM D-256 notched Izod buffer test under the conditions of ℃, injection pressure 400 kg / m ² and mold temperature 140 ℃. Pieces were prepared and their mechanical properties were measured. Table 1 shows the results.

The glass fiber length distribution of the notched Izod buffer specimen was measured by cutting the fracture surface of the buffer specimen with a diamond cutter, burning the resin in an electric furnace at 600 ° C for 10 hours, and removing the resin. Glass fiber length with magnifier,
The measurement was performed under the conditions that the number of measurements was 1000 or more, the minimum glass measurement length was 25 microns or more, and the glass length measurement width (class width) was 25 microns.

 Table 2 shows the results.

Comparative Examples 1 and 2 Physical properties and glass fiber length distribution were evaluated in the same manner as in Example 1 for pellets of a commercial competitor compounded with 60% by weight of PPS resin and 40% by weight of glass fiber.

 The results are shown in Tables 1 and 2.

(Effect of the Invention) As is clear from Table 1, the material of the present invention was found to exhibit extremely high toughness, and no float of glass fiber was observed on the surface of the obtained molded article. Therefore, the material of the present invention is very useful as a coating or sealing material for electric and electronic parts, a substrate for printed wiring boards, a connector for various electric parts, a material for complicated shaped parts, and the like.

Claims (1)

(57) [Claims] 1. A polyphenylene sulfide resin molding material containing glass fibers, wherein the glass fibers are glass fibers having a fiber length of 25 μm or more and 150 μm or less and less than 15% by weight of all glass fibers, and glass fibers having a fiber length of 25 μm or more and 300 μm or less. A polyphenylene sulfide resin molding material, wherein the fiber is 35 to 60% by weight of the total glass fiber, and the average aspect ratio of the glass fiber in the molding material is 17 to 30.