JPH0760785A - Synthetic resin molded product and its manufacture - Google Patents

Abstract

PURPOSE:To improve even a shock strength while holding superiority in surface sharpness, little warp, and mechanical strength. CONSTITUTION:A synthetic resin molded product is obtained by injection molding method and the synthetic resin molded product (C) is obtained by a method wherein polyphenylene ether resin sheet (A) is cut off into a fixed form, after fitting to one side of a mold cavity, compounded and reinforced polyphenylene ether molding material (B) is infected and cast over the sheet (A), the sheet (A) and molding material (B) are laminated and integrated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin molded article such as an automobile exterior material which is required to have a clear image surface, and a method for producing the same. Surface sharpness is a measure of how sharply an image of an object is projected on the surface of an automobile exterior material, etc., and it is a measure of how good the painting finish is. This is an important property for exterior materials. Since the conventional metallic exterior material is heavy and lacks the degree of freedom in design, the commercialization of a synthetic resin exterior material is awaited.

[0002]

2. Description of the Related Art If an automobile exterior material can be molded by injection molding using a synthetic resin, there is a possibility that the weight can be reduced and the degree of freedom in design can be expanded. On the other hand, as an automobile exterior material, a linear expansion coefficient is usually required to be 5 × 10 ⁻⁵ / ° C. or less. Therefore, when a synthetic resin is used for the above purpose, glass fibers are usually blended to reduce the linear expansion. However, the material containing glass fiber has a poor surface appearance because the glass fiber floats on the surface when it is injection-molded, and the surface clarity is not good even if it is applied with a coating, so it cannot be put to practical use. There is. By adding glass fiber to polyphenylene ether resin, heat resistance can be improved by about 20 ° C and mechanical strength such as tensile strength, tensile modulus and bending strength can be improved by about 2 times. However, there is a problem that the resin is scattered due to brittle fracture of the fracture mode.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to synthesize an automobile exterior material, etc. which is excellent in surface sharpness, has less warpage, and can improve mechanical strength while maintaining impact strength. It is to provide a resin molded product and a manufacturing method thereof.

[0004]

SUMMARY OF THE INVENTION The present inventors have proposed a method of mounting a thermoplastic resin sheet in a mold cavity and further injecting another thermoplastic resin by injection to form a laminated integral molding (CF).
It was found that the above-mentioned problems can be solved by utilizing the I technology) and using a composite reinforced polyphenylene ether resin as a molding material, and the present invention has been accomplished. That is, the present invention is a synthetic resin molded article obtained by an injection molding method, in which a sheet (A) made of polyphenylene ether resin is cut into a predetermined shape and mounted on one surface of a mold cavity, and then a composite reinforced polyphenylene ether molding material ( B) is injected and injected onto the sheet (A) in the mold cavity, and the sheet (A) is injected.
The present invention relates to a synthetic resin molded product (C) obtained by laminating and integrating a molding material (B).

The polyphenylene ether resin used in the present invention is a polymer obtained by an oxidative coupling reaction of a monomer having a 2,6-xylenol structure, and is a material excellent in mechanical properties, heat resistance and electric properties. The polyphenylene ether resin can also be used as a modified polyphenylene ether resin obtained by blending or grafting a styrene resin in order to improve the melt fluidity of the resin during injection molding. Further, a flame retardant, an ultraviolet absorber, a stabilizer, a lubricant, etc. may be added to the above resin composition as an additive for use.

When the sheet (A) made of polyphenylene ether resin is laminated and formed with a molding material and the curvature (H / D) of the molded article exceeds 0.1, the resin flowing on the sheet is used to shape the product. Wrinkles may occur because the edge of the sheet cannot be squeezed with resin. In such a case, it is preferable to perform preforming by vacuum forming or the like, and for example, straight, drape, plug assist, and air blow forming methods can be applied. The thickness of the sheet (A) is preferably 0.3 mm or more, particularly preferably 0.3 mm.
When a glass having a thickness of up to 3 mm is used, the appearance of the molded product obtained by laminating and molding is not affected by the glass fiber and is excellent in appearance. Further, when the shape is imparted by the above vacuum forming or the like, the shapeability is excellent.

The thermoplastic resin used in the composite reinforced polyphenylene ether molding material (B) used in the present invention may be one having a weldability with the polyphenylene ether resin sheet (A). Specifically, the above-mentioned polyphenylene ether may be used. Resin compositions, polyphenylene ether resin compositions / styrene-based resin compositions, polyphenylene ether resin compositions / ABS-based resin compositions, and the like can be exemplified, but use of a polyphenylene ether resin composition modified with a styrene-based resin is particularly preferable for moldability. Is desirable from the point of.

The reinforcing material usable for the above composite reinforced polyphenylene ether molding material (B) has improved mechanical strength,
It is compounded in the resin for the purpose of reducing the molding shrinkage or the linear expansion coefficient, and specifically, glass, carbon,
Fibers or flakes of organic / inorganic substances such as metals, whiskers, silicon carbide and boron are appropriately used. Among the above fillers, glass fibers or glass flakes are particularly desirable. The selection and blending ratio of the above-mentioned filler are determined in consideration of improvement of mechanical strength and reduction of molding shrinkage or linear expansion coefficient.

When the type and blending ratio of the filler are selected according to the molding shrinkage, the molding shrinkage is 3.2 mm in thickness, 1
Using a 01.6 mm disk mold, the value obtained by the formula 100 x (mold size-molded product size) / (mold size) is 0.3% or less in the direction parallel to the resin gate, and in the vertical direction. 0.
It is preferably 5% or less. The molding shrinkage ratio is, for example, when the polyphenylene ether resin modified with a styrene resin is used as the composite reinforced polyphenylene ether molding material, the temperature of the molten resin is 280.
It is measured under the measuring conditions of 100C and a mold temperature of 100C. If the molding shrinkage ratio exceeds the above value, the difference in molding shrinkage between the surfaces (sheet surface and material surface) of the laminated molded product is large, and thus warpage may occur over the entire surface of the molded product. When selecting the filler and the blending ratio based on the linear expansion coefficient, the linear expansion coefficient (the value measured according to ASTM D696) is preferably 5 × 10 ⁻⁵ / ° C. or less. If the coefficient of linear expansion is equal to or more than the above value, warpage may occur over the entire surface of the molded product as in the above case.

As a composite reinforced polyphenylene ether molding material excellent in mechanical strength and satisfying the above-mentioned molding shrinkage ratio or linear expansion coefficient, for example, glass fibers, glass flakes or a glass fiber or glass flakes in a polyphenylene ether resin modified with a styrene resin is used. An example of the composition is a mixture of 10 to 50% by weight. In addition, a large amount of waste materials such as sprues and runners are usually generated in the injection molding, but in the present invention, a part of the resin used in the composite reinforced polyphenylene ether molding material (B), specifically, the recycled material mixing ratio is It is also possible to use 30% or less of glass fibers after pulverizing the above waste materials and adding a suitable amount of glass fibers. If the recycled material mixing ratio is 30% or more, the tensile strength, bending strength, and bending elastic modulus may decrease.
It can be selected within the above range depending on the use conditions.
When the synthetic resin molded product obtained in the present invention is further subjected to coating treatment, the molded product is excellent in surface sharpness. The coating can be generally carried out by a spray method using urethane paint, acrylic paint or the like.

Known conditions can be applied to the injection conditions and the like of the present invention. The injection molding machine used may be a conventional one, and a molded product can be produced by the following method. The steps of the present invention are illustrated below. (1) Attaching the sheet to the die To attach the sheet (A) made of polyphenylene ether resin to the die, attach a plurality of pins to the die and make holes at positions corresponding to the sheet. And a method in which a magnet is embedded in a mold and an iron piece is attached at a position corresponding to that of the sheet and then attached. The sheet (A) is preferably mounted on the fixed side of the mold cavity. (2) Mold clamping After mounting the above-mentioned sheet, mold clamping is performed. (3) Injection of molten resin A composite reinforced polyphenylene ether molding material (B) is injected and injected from an injection molding machine to obtain a sheet (A) and a molding material (B).
Are integrally molded.

(4) Cooling and mold release After injection of the resin, the molten resin is cooled and solidified by a conventional method to obtain a molded product after mold release. (5) Coating When coating a molded product obtained for automobile exterior or home electric appliance, it is coated by a conventional method such as a spray method. By the above-mentioned molding, the sheet (A) and the molding material (B) are completely heat-welded by the heat and pressure at the time of molding, and despite the difference in molding shrinkage on each surface, there is no warp on the entire surface and The sheet surface had excellent appearance. Further, the resin produced brittle fracture even when subjected to an impact test of the molded article produced by the present invention, but the sheet and the molding material are firmly welded, and the modified polyphenylene ether resin sheet is a ductile material, so the resin Was prevented from scattering.

Although the manufacturing method and the mold structure of the present invention have been described above, the present invention is not limited to the above description. Further, as molding conditions, when the polyphenylene ether resin composition modified with a styrene resin is used as the molding material and the molding is carried out at a resin temperature of 290 ° C. or higher, the fluidity of the resin and the adhesive force of the sheet can be increased. . Mold temperature is when using printed sheet,
It is preferably not higher than the heat resistant temperature of the ink. Also according to the invention,
Since a product with good quality and sharpness can be obtained, and recycled materials can be used, cost reduction can be expected and further environmental protection effect can be expected.

[0014]

EXAMPLES The present invention will be described in detail below with reference to examples. In addition, in the present example, the evaluation of the molded product was performed by the following method. Evaluation of surface sharpness When an object was transferred onto the surface of a molded product, the image was visually observed and evaluated from the degree of distortion. ◯: There is no image distortion. X: The image is distorted. Measurement of Adhesive Force between Sheet and Molding Material The 90-degree peel strength between the sheet and molding material was measured. The measurement is performed by peeling from the side opposite to the gate of the molded product in which the sheet and the molding material are integrated, and the 90-degree peel strength (kgf / c
m) was measured with a spring only. The evaluation was displayed based on the following numerical values. ◯: 90 ° peel strength of 5 kgf / cm or more ×: 90 ° peel strength of less than 5 kgf / cm

Measurement of warp A warp was evaluated using a three-dimensional dimension measuring machine (manufactured by Mitoyo Seisakusho). Evaluated by the maximum height difference (Δh) of the molded product,
Displayed based on the following numerical values. ◯: The amount of warp of the molded product is 0.1 mm or less ×: The amount of warp of the molded product exceeds 0.1 mm Cold / heat repeat test For adhesion and warpage, further repeated cold heat of −30 ° C. and 80 ° The test was repeated and the test was conducted. Ie -3
After repeating the operation of performing heat treatment at 0 ° C. for 2 hours and at 80 ° C. for 2 hours (there was a change time of 2 hours until reaching each temperature) 20 times, the adhesive strength and warpage were evaluated. .

Example 1 A sheet of polyphenylene ether resin modified with a styrene resin having a thickness of 0.5 mm was punched out by a press machine in accordance with the size of a die mounting portion (disk shape of 100 mmφ). The mold cavity is designed so that the molded product has a wall thickness of 3 mm. After mounting the sheet in the fixed side cavity of the mold, the mold is clamped, and a polyphenylene ether resin material modified with a glass fiber-blended styrene resin by an injection molding machine (blending ratio of glass fiber in the composition: 10% by weight, molding shrinkage) The ratio is 0.3% in the parallel direction and 0.
5% and the coefficient of linear expansion was 4.5 × 10 ⁻⁵ / ° C.). The molding conditions were a resin temperature of 300 ° C., a mold temperature of 70 ° C., and an injection pressure of 1200 kgf / cm ² . The molded product was spray-coated with a urethane paint, and each product was evaluated. The evaluation results are shown in Table 1.

Example 2 Polyphenylene ether resin modified with glass fiber-containing styrene resin (glass fiber content in composition: 30% by weight, molding shrinkage 0.1% in parallel direction, 0.3% in vertical direction) The molded product was manufactured in the same manner as in Example 1 except that the linear expansion coefficient was 2.5 × 10 ⁻⁵ / ° C.), and the evaluation after coating was performed. The evaluation results are shown in Table 1.

Example 3 A molded article was produced in the same manner as in Example 1 except that a 0.3 mm polyphenylene ether sheet was used, and evaluation after coating was performed. The evaluation results are shown in Table 1.

Comparative Example 1 Except that a 0.5 mm polycarbonate sheet was used,
A molded product was manufactured in the same manner as in Example 1 and evaluated after coating. The evaluation results are shown in Table 1.

Comparative Example 2 Using the same polyphenylene ether resin material as that used in Example 2, a non-laminated molded product was prepared under the same conditions as in Example without mounting a sheet, and comparison of its image clarity was performed. I went. The evaluation results are shown in Table 1.

[0021]

[Table 1] Example 1 Example 2 Example 3 Comparative example 1 Comparative example 2 Surface image clarity ○ ○ ○ ○ × Repeated before thermal test 1) Adhesion ○ ○ ○ × − 2) Sled ○ ○ ○ ○ − Repeated After cold heat test 1) Adhesive strength ○ ○ ○ × − 2) Warp ○ ○ ○ ○ −

[0022]

The integrally molded product obtained by the present invention is
It has excellent surface clarity, can prevent warping, has excellent adhesive force between the sheet and the filler-containing material, and has excellent adhesive force after the cold heat test.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location B29K 671: 00 B29L 9:00 (72) Inventor Katsumi Yoshida 5-6-2 Higashi-Hachiman, Hiratsuka-shi, Kanagawa Prefecture Gas Chemical Co., Ltd. Plastics Center

Claims (9)

[Claims] 1. A synthetic resin molded article obtained by an injection molding method, comprising cutting a polyphenylene ether resin sheet (A) into a predetermined shape and mounting it on one side of a mold cavity, followed by composite reinforced polyphenylene ether molding. A synthetic resin molded product (C) obtained by injection-injecting a material (B) onto a sheet (A) and stacking and integrating the sheet (A) and the molding material (B). 2. The synthetic resin molded product (C) according to claim 1, wherein the polyphenylene ether resin sheet (A) has a thickness of 0.3 mm or more. 3. The synthetic resin molded product (C) according to claim 1, wherein the polyphenylene ether resin sheet (A) is formed in advance by vacuum molding. 4. The thermoplastic resin used in the polyphenylene ether resin sheet (A) and / or the composite reinforced polyphenylene ether molding material (B) is a thermoplastic resin modified by blending or grafting with a styrene resin. The synthetic resin molded product (C) according to claim 1. 5. The synthetic resin molded article (C) according to claim 1, wherein the reinforcing material used for the composite reinforced polyphenylene ether molding material (B) is glass fiber or glass flake. 6. A molding shrinkage ratio (thickness: 3.2 mm, outer diameter: 101. mm) of the composite reinforced polyphenylene ether molding material (B).
The molding shrinkage ratio when a molded product is obtained using a 6 mm disk mold, and the value obtained by the formula 100 x (mold size-molded product size) / (mold size) is , 0.3% or less in the direction parallel to the resin gate and 0.
The synthetic resin molded product (C) according to any one of claims 1 to 5, which is 5% or less. 7. The synthetic resin molded product (C) according to claim 1, wherein the composite reinforced polyphenylene ether molding material (B) has a linear expansion coefficient of 5 × 10 ⁻⁵ / ° C. or less. 8. A synthetic resin molded article (D) having excellent surface sharpness obtained by further coating the synthetic resin molded article (C) according to claim 1 or 2. 9. A method for producing a synthetic resin molded product by injection molding, comprising cutting a sheet (A) made of a polyphenylene ether resin into a predetermined shape and mounting the sheet on one side of a mold cavity, and then reinforced the composite reinforced polyphenylene ether. A method for producing a synthetic resin molded product (C), comprising injecting a molding material (B) onto the sheet (A), and stacking and integrating the sheet (A) and the molding material (B).