JPH0760784A - Synthetic resin molded product and its manufacture - Google Patents

Abstract

PURPOSE:To improve even shock strength while holding superiority in surface sharpness and heat resistance, little warp and deformation and mechanical strength. CONSTITUTION:A synthetic resin molded product is obtained by injection molding and the synthetic resin molded product (C) is obtained by a method wherein a polyphenylene ether-crystalline polyamide resin composition sheet (A) is cut off into a fixed form, fitted to one side of a mold cavity, a compounded and reinforced polyamide resin molding material (B) is infected and cast on 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 freedom of design, the commercialization of the 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. 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 mixed with glass fiber has a problem that when it is injection molded, the surface appearance is poor because the glass fiber floats on the surface, and the image clarity is not good even if it is coated, and it cannot be put to practical use. is there. In addition, the coating of metallic exterior materials,
Baking coating is generally used, and the temperature of the baking furnace is about 160 ° C, which causes deformation due to insufficient heat resistance, and in the case of materials with poor chemical resistance, stress cracks may occur due to organic solvents, etc. there were.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above problems, to provide excellent surface sharpness and heat resistance, and to prevent warpage.
It is an object of the present invention to provide a synthetic resin molded article such as an automobile exterior material that can be improved in impact strength while maintaining mechanical strength with little deformation, and a method for producing the same.

[0004]

Means for Solving the Problems The inventors of the present invention mount a sheet in a mold cavity, inject another thermoplastic resin, and integrally mold the sheet (hereinafter sometimes referred to as CFI technology). It was found that the above-mentioned problems can be solved by using a composite-reinforced polyphenylene ether-crystalline polyamide resin composition as a molding material by utilizing the above, and thus completed the present invention. That is, the present invention is
A synthetic resin molded product obtained by injection molding, in which a sheet (A) made of a polyphenylene ether-crystalline polyamide resin composition is cut into a predetermined shape and mounted on one side of a mold cavity for composite reinforcement. Polyphenylene ether-crystalline polyamide molding material (B) is used as a sheet (A)
It is an invention relating to a synthetic resin molded product (C) obtained by injection-injecting the same onto a sheet (A) and a molding material (B) which are laminated and integrated.

As the crystalline polyamide used in the present invention, polyamide 6, polyamide 66, polyamide 11,
Polyamide 12, polyamide MXD6 obtained from metaxylylenediamine and adipic acid, polyamide 6 and 66
Examples thereof include copolymers of When polyamide 11, polyamide 12, polyamide MXD6 or the like having a low water absorption rate is used among the above polyamides, the water absorption rate can be reduced and the dimensional stability can be greatly improved.

The polyphenylene ether used in the present invention is a polymer obtained by subjecting a monomer having a 2,6-xylenol structure to an oxidative coupling reaction and has mechanical properties,
It is a material with excellent heat resistance and electrical characteristics. However,
In order to improve fluidity during injection molding, polyphenylene ether is usually modified with an unsaturated carboxylic acid or its anhydride, or a modifier having a carboxyl group and melt-kneaded with a crystalline polyamide, or with polyphenylene ether and crystals. A mixture of a polymerizable polyamide and a modifier is melt-kneaded to form a polymer alloy for use. Use of the sheet (A) and / or the molding material (B) in which the polyamide in the polyphenylene ether-polyamide-based resin composition is 30 to 60% by weight makes it possible to obtain a molded article particularly excellent in mechanical strength, heat resistance and the like. You can 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.

The thickness of the sheet (A) is preferably 0.3.
When the thickness of the product is not less than mm, particularly preferably about 0.3 to 3 mm, the appearance of the product at the time of lamination molding is free from irregularities due to the influence of glass fibers and the like, and therefore the appearance is improved. Further, when a shape is imparted by the above vacuum molding or the like, the shapeability during injection molding is excellent. If necessary, the sheet (A) may have a character mark formed by printing, painting or the like in advance. When the sheet (A) is laminated with a molding material and the product has a curvature (H / D) of more than 0.1, the resin flowing at the top of the sheet causes the resin to be applied to the end of the sheet. There is a problem that wrinkles occur because it cannot be fully squeezed.
In such a case, it is preferable that the sheet is pre-dried and then pre-formed by vacuum forming or the like, and for example, straight, drape, plug assist, and air blow forming methods can be applied.

It is important that the composite reinforced polyphenylene ether-crystalline polyamide molding material (B) used in the present invention has weldability with the sheet (A) made of the above polyphenylene ether and crystalline polyamide. is there. Specific examples thereof include a polyphenylene ether / polyamide 6 resin composition selected from the polyphenylene ether and crystalline polyamide group, a polyphenylene ether / polyamide 66 resin composition, and a polyphenylene ether / polyamide MXD6 resin composition. When the composition is modified into a polymer alloy, welding of the sheet and the molding material is possible.

When the adhesive strength is weak, the heat of crystal fusion measured by a differential scanning calorimeter (heating rate 20 ° C./min)
However, by blending the amorphous polyamide of less than 1 cal / g polymer into the sheet (A) or the molding material (B), the amorphous polyamide is added to the resin composition at a concentration of 3 to 15% by weight. It becomes possible to easily increase the adhesive strength. As an amorphous polyamide, the heat of crystal fusion is 1 cal
Adhesive strength is hardly improved even if a polyamide of not less than / g polymer is added. Further, when the addition ratio of the amorphous polyamide is less than 3% by weight, the effect of improving the adhesive strength is small, and even when the amount exceeds 15% by weight, the adhesive strength is not significantly improved.

The reinforcing filler usable in the composite reinforced polyphenylene ether-crystalline polyamide molding material (B) is a resin for the purpose of reducing mechanical strength, heat resistance, molding shrinkage or linear expansion coefficient. It is blended in, specifically, glass, carbon, metal, whiskers,
Fibers or flakes of organic or inorganic substances such as silicon carbide or boron, or a mixture thereof are appropriately used. Among the above fillers, glass fiber is particularly desirable. The selection and blending ratio of the above-mentioned filler are determined in consideration of the mechanical strength and the reduction of the molding shrinkage ratio or the linear expansion coefficient described below.

When the selection of the filler and the blending ratio are selected according to the molding shrinkage, the molding shrinkage uses a disk mold having a thickness of 3.2 mm and an outer diameter of 101.6 mm, and the formula 100 × (mold size- It is desirable that the value obtained by (molded product dimension) / (die dimension) is 0.5% or less in the direction parallel to the resin gate and 0.6% or less in the vertical direction. The molding shrinkage ratio is measured, for example, under the conditions of a molten resin temperature of the molding material of 280 ° C. and a mold temperature of 80 ° C. If the molding shrinkage ratio exceeds the above value, the molding shrinkage difference 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 is preferably 5 × 10 ⁻⁵ / ° C. or less. Here, the coefficient of linear expansion is a value measured according to ASTM D696. 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 the composite reinforced polyphenylene ether-crystalline polyamide molding material having excellent mechanical strength, heat resistance and satisfying the molding shrinkage ratio or the linear expansion coefficient, for example, glass fiber, glass flake, or a mixture thereof. 10 to 50% by weight of the above are included. In addition, a large amount of waste materials such as sprues and runners are usually generated in injection molding, but in the present invention, a part of the resin used in the composite reinforced molding material (B) and all the waste materials are crushed, and then glass fibers are preferably used. It can also be used by adding an appropriate amount. When the synthetic resin molded product obtained by the present invention is further subjected to coating treatment, the molded product obtained is excellent in surface clarity. The coating can be usually performed by a spray coating 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 exemplified below. (1) Attachment of sheet to mold The attachment of the sheet (A) made of polyphenylene ether-crystalline polyamide resin composition to the mold is provided with a plurality of pins on the mold, and the position corresponding to that of the sheet is provided. There is a method of making a hole in the sheet and attaching it, or a method of embedding a magnet in a die and attaching an iron piece at a position corresponding to that of the sheet and attaching the sheet. 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-crystalline polyamide molding material (B) is injected and injected from an injection molding machine to integrally laminate the sheet (A) and the molding material (B). (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 article obtained for automobile exteriors or home appliances, it is coated by a conventional 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.

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 a molding processing condition, by molding at a resin temperature of 290 ° C. or higher when a polyphenylene ether-polyamide 6-based polymer alloy is used as a molding material, the fluidity of the resin and the adhesive force with the sheet can be enhanced. For the purpose of delaying the crystal acceleration of the molding material, the die temperature can be heated at 60 ° C. or higher and the glass transition temperature or lower to strengthen the adhesion. When using a printed sheet, the temperature is preferably not higher than the heat resistant temperature of the ink. Further, according to the present invention, it is possible to obtain a product having good image clarity in terms of quality, and it is possible to use a recycled material, so that cost reduction can be expected and further an environmental protection effect can be expected.

[0015]

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 display of evaluation is based on the following criteria. ◯: 90 ° peel strength of 5 kgf / cm or more ×: 90 ° peel strength of less than 5 kgf / cm

Measurement of warpage and deformation The warpage was evaluated using a three-dimensional size measuring machine (manufactured by Mitoyo Seisakusho). Evaluated by the maximum height difference (Δh) of the molded product,
The display of evaluation is based on the following criteria. ◯: 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 adhesive strength and warp, further repeated cold / heat test of −30 ° C. and 80 ° C. The test was repeated. 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 obtained by molding a polyphenylene ether-polyamide 6 resin composition having a thickness of 0.5 mm and modified with maleic anhydride was pressed by a press machine to obtain a size (100 mmφ) of a die mounting portion.
The sheet was punched out in accordance with the disk shape). 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 was clamped, and a maleic anhydride-modified polyphenylene ether-polyamide 6 resin material containing glass fibers in an injection molding machine (glass fiber compounding ratio in the composition: Thirty
%, The molding shrinkage was 0.3% in the parallel direction, 0.4% in the vertical direction, and the linear expansion coefficient was 3.3 × 10 ⁻⁵ / ° C.). The molding conditions were a resin temperature of 290 ° 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 coating, and baked for 2 hours in a drying oven at 170 ° C., and each product was evaluated. The evaluation results are shown in Table 1.

Example 2 A polyphenylene ether-polyamide 6 resin composition modified with maleic anhydride and an amorphous polyamide (manufactured by Unitika Ltd., trade name: CX3000) were used in the composition.
Molding material added so as to be in a weight% (glass fiber blending ratio in the composition: 20% by weight, molding shrinkage is 0.4% in the parallel direction, 0.43% in the vertical direction, and the linear expansion coefficient is 2.9 × 10 ⁻⁵ / ° C.) and the mold temperature is 50 ° C.
A molded product was manufactured in the same manner as in Example 1 except that the above-mentioned procedure was carried out, the same coating as in Example 1 was performed, and the evaluation after coating was performed. The evaluation results are shown in Table 1.

Example 3 A molded article was prepared in the same manner as in Example 1 except that a maleic anhydride-modified polyphenylene ether-polyamide 6 resin composition similar to that used in Example 1 was used with a sheet thickness of 0.3 mm. It was manufactured and evaluated after coating in the same manner as in Example 1. The evaluation results are shown in Table 1.

Comparative Example 1 The same polyphenylene ether as used in Example 1
Using a polyamide 6 resin material, a non-laminated molded product was prepared under the same conditions as in the example without mounting a sheet, and evaluated after coating. The evaluation results are shown in Table 1.

[0021]

[Table 1] Example 1 Example 2 Example 3 Comparative Example 1 Image clarity ○ ○ ○ × Adhesion before repeated thermal heat test ○ ○ ○ − Sled ○ ○ ○ − Adhesion after repeated thermal heat test ○ ○ ○ − Sled ○ ○ ○ −

[0022]

The integrally molded product obtained by the present invention is
It has excellent image clarity and heat resistance, 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 Reference number within the agency FI Technical indication location B29L 7:00 9:00 (72) Inventor Katsumi Yoshida 5-6-2 Higashi-Hachiman, Hiratsuka-shi, Kanagawa Sanryo Gas Chemical Co., Ltd. Plastics Center

Claims (11)

[Claims] 1. A synthetic resin molded article obtained by injection molding, wherein a sheet (A) made of a polyphenylene ether-crystalline polyamide resin composition is cut into a predetermined shape and mounted on one side of a mold cavity, A synthetic resin molded product (C) obtained by injection-injecting the composite-reinforced polyphenylene ether-crystalline polyamide-based molding material (B) onto the 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 thickness of the polyphenylene ether-crystalline polyamide resin composition sheet (A) mounted in the mold cavity is 0.3 mm or more. 3. The synthetic resin molded product (C) according to claim 1, wherein the sheet (A) made of a polyphenylene ether-crystalline polyamide resin composition has been previously given a shape by vacuum molding. 4. The crystalline polyamide in the polyphenylene ether-crystalline polyamide resin composition used for the sheet (A) and the molding material (B) is 30 to 40% by weight. The synthetic resin molding (C) described. 5. The polyphenylene ether-crystalline polyamide resin composition used for the sheet (A) and the molding material (B) is further heated by a crystal melting heat (using a differential scanning calorimeter, a temperature rising rate of 20 ° C./min). Measurement value at 1cal
3. The synthetic resin molded article (C) according to claim 1 or 2, wherein an amorphous polyamide of less than 1 g / g polymer is blended so that the amount of the amorphous polyamide in the resin composition is 3 to 15% by weight. . 6. The synthetic resin molded product according to claim 1, wherein the reinforcing material in the composite-reinforced polyphenylene ether-crystalline polyamide molding material (B) is at least glass fiber or glass flake. C). 7. A molding shrinkage ratio of a composite reinforced molding material (B) (a molding shrinkage ratio when a molded product is obtained by using a disk mold having a thickness of 3.2 mm and an outer diameter of 101.6 mm, 10
0 × (mold size-molded product size) / (mold size) value is 0.5% or less in the direction parallel to the resin gate,
The synthetic resin molded product (C) according to any one of claims 1 to 6, having a content of 0.6% or less in the vertical direction. 8. The synthetic resin molded product (C) according to claim 1, wherein the linear expansion coefficient of the composite reinforced molding material (B) is 5 × 10 ⁻⁵ / ° C. or less. 9. A synthetic resin molded article (D) which is obtained by further coating the synthetic resin molded article (C) according to claim 1 or 2 and which is excellent in surface image clarity. 10. The synthetic resin molded article according to claim 1, wherein the molded article is for an automobile exterior material. 11. A method for producing a synthetic resin molded product by injection molding, comprising cutting a sheet (A) made of a polyphenylene ether-crystalline polyamide resin composition into a predetermined shape and mounting it on one side of a mold cavity. Then, the composite-reinforced polyphenylene ether-crystalline polyamide-based molding material (B) is injected and injected onto the sheet (A), and the synthetic resin molding (C) in which the sheet (A) and the molding material (B) are laminated and integrated. )
Manufacturing method.