JPH0639113B2 - Polyarylene sulfide resin molded product having welded portion - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molded article injection-molded from two or more gates using the improved polyarylene sulfide resin composition. More specifically, the present invention relates to a molded article injection-molded from two or more gates using the polyarylene sulfide resin composition improved to improve the strength of the weld portion of the molded article.

[Conventional technology and its problems]

In recent years, electric / electronic equipment parts materials, automobile equipment parts materials,
BACKGROUND ART Thermoplastic resins having high heat resistance and chemical resistance have been required for chemical equipment parts materials. Polyarylene sulfide resin typified by polyphenylene sulfide is also one of the resins that meets this requirement, but when this resin is molded, the flow front interfaces of two or more resins merge and fuse in the mold cavity. It has a drawback that the mechanical properties of the welded portion, that is, the welded portion, become extremely low. Especially in the case of molding a large-sized molded product or a molded product having a complicated shape, it is often convenient to perform injection molding by providing two or more gates in the mold cavity of one molded product. The formation of welds is unavoidable in molded products with more than one gate, and the weak point of welds in such cases is fatal, and there is a problem that the welds will be destroyed when subjected to thermal stress or mechanical stress. It is easy to happen. In particular, when a molded product having a complicated shape is manufactured by secondary processing such as ultrasonic welding, there is a problem that breakage from the weld portion remarkably increases. Therefore, attempts have conventionally been made to improve the mechanical properties of the weld portion, and the following are generally known.

(1) Make improvements to the mold design. For example, a cold slag well is attached and removed after cooling. Alternatively, the number of gates is increased so that the material temperature does not decrease at the fusion point. Or change the position of the gate.

(2) After processing, holes are formed in necessary parts to prevent weld formation at the time of molding.

(3) Use a composition with improved flow properties. (JP-A-59-
11357, JP 59-11358, JP 57-70157
(4) An inorganic filler having an effect of improving weld strength is used (JP-A-57-70157).

However, each of these methods has problems. That is, in the method of cold slag well of (1),
The formation of welds cannot be avoided by molding with two or more gates, and an increase in the number of gates has the opposite effect in the case of polyarylene sulfide resin.

In addition, the method (2) requires a lot of man-hours and leads to an increase in cost, and in addition, the formation of a weld portion cannot be avoided in the case of molding with two or more gates. Although the methods (3) and (4) show the improvement effect, they are not strong enough and the applicable molding products are limited. Especially, the improvement of the weld part that occurs when molding with two or more gates. The effect is not sufficient.

Therefore, polyarylene sulfide resin is a material that is heat resistant and suitable for precision molding.
Molded products obtained by injection molding with gates at more than one place have limited application applications because the mechanical properties of welds are particularly low.

[Means for solving problems]

The inventors of the present invention, such as large molded products and molded products of complicated shapes,
As a result of investigating various additives in order to improve particularly remarkable defects occurring in the weld portion of a polyarylene sulfide resin molded product having a weld portion which cannot be avoided by a mold design having two or more gates, epoxyalkoxysilane , At least 1 selected from the group consisting of mercaptoalkoxysilane and vinylalkoxysilane
The addition of one kind of silane compound changes the solidification / crystallization behavior of the composition, and as a result, even when injection molding is performed using two or more gates, the fusion state of the resin in the weld portion is improved. The inventors have found that mechanical properties are improved, and have completed the present invention.

That is, the present invention relates to (A) 100 parts by weight of a polyarylene sulfide resin, and 0.01 to 5 parts by weight of at least one silane compound selected from the group consisting of (B) epoxyalkoxysilane, mercaptoalkoxysilane and vinylalkoxysilane. (C) A molded part made of a polyarylene sulfide resin composition containing 0 to 400 parts by weight of an inorganic filler, the welded part being obtained by injection molding at least two gates per at least one molded part. A polyarylene sulfide resin molded article having the same is provided.

In the present invention, the base resin is (A) a polyarylene sulfide resin having a structural formula (Where Ar is an aryl group) is a polymer containing 70 mol% or more of repeating units represented by a structural formula. Is a polyphenylene sulfide having a repeating unit of 70 mol% or more. Among them, those having a melt viscosity of 10 to 20000 poises, particularly 100 to 5000 poises, measured under conditions of a temperature of 310 ° C. and a shear rate of 1200 / sec are suitable.

Further, as the base resin of the present invention, other thermoplastic resins may be supplementarily used in a small amount in addition to the polyarylene sulfide resin depending on the purpose. Any other thermoplastic resin may be used as long as it is a thermoplastic resin that is stable at high temperatures. For example, aromatic polyester such as polyethylene terephthalate and polybutylene terephthalate, and aromatic polyester composed of diol or oxycarboxylic acid, polyamide, polycarbonate, ABS, polyphenylene oxide, polyalkyl acrylate, polyacetal, polysulfone, polyether sulfone, polyether. Examples thereof include imide, polyetherketone, and fluororesin. Further, these thermoplastic resins may be used as a mixture of two or more kinds.

The silane compound added and blended as the component (B) of the composition of the present invention is one or more of epoxyalkoxysilane, mercaptoalkoxysilane and vinylalkoxysilane. As the epoxyalkoxysilane, any silane compound having one or more epoxy groups in one molecule and two or three alkoxy groups is effective, and for example, γ-glycidoxypropyltrimethoxysilane, Examples thereof include β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and γ-glycidoxypropyltriethoxysilane. As the mercaptoalkoxysilane, any silane compound having one or more mercapto groups in one molecule and two or three alkoxy groups is effective, and for example, γ-mercaptopropyltrimethoxysilane, γ -Mercaptopropyltriethoxysilane and the like. As the vinylalkoxysilane, any silane compound having one or more vinyl groups in one molecule and two or three alkoxy groups is effective, and examples thereof include vinyltriethoxysilane and vinyltrimethoxysilane. , Vinyltris (β-methoxyethoxy) silane and the like.

The amount of the alkoxysilane used in the present invention is 0.0 per 100 parts by weight of the polyarylene sulfide resin.
It is 1 to 5 parts by weight, preferably 0.1 to 2 parts by weight. If the amount is less than 0.01 parts by weight, the intended effect cannot be obtained, and if it is too large, mechanical properties are deteriorated, which is not preferable.

Although the inorganic filler (C) used in the present invention is not always an essential component, it is a molded product with excellent properties such as mechanical strength, heat resistance, dimensional stability (deformation resistance, warpage), and electrical properties. In order to obtain the above, it is preferable to mix them, and a fibrous, powdery or plate-like filler is used for this purpose.

As the fibrous filler, glass fiber, asbestos fiber,
Carbon fiber, silica fiber, silica-alumina fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, stainless steel,
Examples thereof include inorganic fibrous substances such as metal fibrous substances such as aluminum, titanium, copper and brass. A particularly representative fibrous filler is glass fiber or carbon fiber. High melting point organic fibrous substances such as polyamide, fluororesin, polyester resin and acrylic resin can also be used.

On the other hand, powdered and granular fillers include carbon black, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc, clay, silicates such as diatomaceous earth and wollastonite, and oxidation. Iron, titanium oxide, zinc oxide, metal oxides such as alumina, calcium carbonate, metal carbonates such as magnesium carbonate, calcium sulfate, metal sulfates such as barium sulfate, other silicon carbide, silicon nitride, boron nitride, Examples include various metal powders.

Examples of the plate-shaped filler include mica, glass flakes, various metal foils and the like.

These inorganic fillers can be used alone or in combination of two or more. The combined use of a fibrous filler, especially glass fiber or carbon fiber, with a granular and / or plate-like filler is a preferable combination particularly in terms of having both mechanical strength, dimensional accuracy, electrical properties and the like.

When using these fillers, it is desirable to use a sizing agent or a surface treatment agent if necessary. Examples of this are functional compounds such as epoxy compounds, isocyanate compounds, silane compounds and titanate compounds. These compounds may be subjected to surface treatment or converging treatment in advance, or may be added at the same time when the materials are adjusted.

The amount of inorganic filler used is polyarylene sulfide resin
0 to 400 parts by weight per 100 parts by weight, preferably 10
~ 250 parts by weight. If it is less than 10 parts by weight, the mechanical strength will be poor, and if it is too large, molding work will be difficult,
There is also a problem with the mechanical strength of the molded product.

Furthermore, in the composition of the present invention, known substances generally added to thermoplastic resins and thermosetting resins, that is, stabilizers such as antioxidants and ultraviolet absorbers, antistatic agents, flame retardants,
Colorants such as dyes and pigments, lubricants, crystallization accelerators (nucleating agents) and the like can be appropriately added depending on the required performance.

The polyarylene sulfide resin composition of the present invention can be prepared by the equipment and method generally used for preparing a synthetic resin composition. That is, necessary components can be mixed, kneaded using a single-screw or twin-screw extruder, and extruded into molding pellets. A method of mixing and molding a part of the necessary components as a masterbatch is also possible. Is.

A feature of the present invention is a molded product obtained by injection molding a polyarylene sulfide resin molded product by providing gates at two or more locations of one mold cavity corresponding to one molded product. And there is a point.
In such a molded product, an interface (weld part) where two or more resin flows corresponding to the number of gates are joined is always formed, the interface region is wide, and the strength defect of the weld part is remarkable,
It causes a fatal obstacle to practical strength. This can be identified by the appearance of linear color unevenness on the surface of the molded product or the appearance of a merged resin flow, which is not preferable in appearance. The present invention is particularly effective in ameliorating the remarkable defects in the weld portion which occur in a molded product using such gates at two or more locations.

Molded products made of polyarylene sulfide resin are used as electric / electronic equipment parts, automobile parts, office equipment parts and many other machine tool parts, but these molded products are generally easy to mold and the like. In many cases, resin is injected and injected from a single gate into a molded product, and a welded part does not always occur in a molded product with such a single-point gate. There are cases where the flow is divided to form the weld portion, but in that case also, there is relatively little strength hindrance occurring in the weld portion.

On the other hand, in the molded product obtained by injection molding from two or more gates as in the present invention, the presence of the welded portion is unavoidable, and the strength problem is particularly remarkable, and the present invention is particularly effective. This is the reason.

[Examples] The present invention is described in more detail below with reference to Examples, but the present invention is not limited thereto.

Example 1 Polyphenylene sulfide resin (Kureha Chemical Industry Co., Ltd.,
Γ-glycidoxypropyltrimethoxysilane was added in an amount shown in Table 1 to the product name "Fortron KPS") and premixed for 5 minutes with a Henschel mixer. Further, commercially available glass fiber (diameter 13 μm, length 3 mm) was added in an amount shown in Table 1 and mixed for 2 minutes.
Pellets of the polyphenylene sulfide resin composition were prepared by subjecting to an extruder at ℃. Then, using an injection molding machine, at a cylinder temperature of 320 ° C. and a mold temperature of 150 ° C., a tensile test piece was formed by using a two-point side-gate test piece mold made so that a weld portion was formed at the center of the tensile test piece. The tensile strength and elongation of each part were measured. For reference, a test piece in which a weld portion due to a one-point gate was not formed was also molded and the same measurement was performed. The results are shown in Table 1.

Comparative Example 1 A test piece was prepared in the same manner as in Example 1 except that γ-glycidoxypropyltrimethoxysilane was not used, and the tensile strength and elongation were measured. The results are shown in Tables 1 to 4.

Example 2 A test piece was prepared in the same manner as in Example 1 except that γ-mercaptopropyltrimethoxysilane was used as the silane compound, and the tensile strength and elongation were measured. The results are shown in Table 2.

Example 3 A test piece was prepared in the same manner as in Example 1 except that vinyltrimethoxysilane was used as the silane compound, and the tensile strength and elongation were measured. The results are shown in Table 3.

Examples 4 to 8 Weld test pieces were prepared in the same manner as in Example 1 except that the materials shown in Table 4 were used as the silane compound, and the tensile strength and elongation of the weld portion were measured. The results are shown in Table 4.

Examples 9 to 11, Comparative Examples 2 to 4 Weld test pieces were prepared in the same manner as in Example 1 except that the materials shown in Table 5 were used as the epoxyalkoxysilane and the inorganic filler. The tensile strength and elongation were measured. The results are shown in Table 5.

Examples 12 to 14 Weld test pieces were prepared in the same manner as in Example 1 except that the materials shown in Table 6 were used as the mercaptoalkoxysilane and the inorganic filler, and the tensile strength and elongation of the weld were measured. did. The results are shown in Table 6.

Examples 15 to 17 Weld test pieces were prepared in the same manner as in Example 1 except that the materials shown in Table 7 were used as the vinylalkoxysilane and the inorganic filler, and the tensile strength and elongation of the weld were measured. did. The results are shown in Table 7.

Examples 18 to 23, Comparative Examples 5 and 6 Weld test pieces were prepared in the same manner as in Example 1 except that the silane compound and the glass fiber were used in the amounts shown in Table 8, and the tensile strength and elongation of the weld portion were measured. The degree was measured. The results are shown in Table 8.

[Effects of the Invention] As is apparent from the above description and Examples, molded articles obtained by injection molding from two or more gates using the polyarylene sulfide resin of the present invention are avoided in such molded articles. It is remarkably improved in mechanical properties such as strength and elongation of the welded part and appearance, and is extremely useful in practice.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Norihito Nonaka, 973 Miyajima, Fuji City, Shizuoka Prefecture, Polyplastics Co., Ltd. (56) References JP 52-52958 (JP, A) JP 57-158256 (JP) , A)

Claims (1)

[Claims] 1. (A) Polyarylene sulfide resin 100
(B) at least one silane compound selected from the group consisting of epoxyalkoxysilane, mercaptoalkoxysilane and vinylalkoxysilane 0.01 to 5 parts by weight (C) inorganic filler 0 to 400 parts by weight A molded product of a polyarylene sulfide resin composition, which is obtained by injection molding from at least two gates to at least one molded product and has a weld portion.