JPH0760787A - Synthetic resin molded product and its manufacture - Google Patents

Abstract

PURPOSE:To make a molding material superior in surface sharpness and have little warp by making use of compounded and reinforced polycarbonate for the molding material. CONSTITUTION:In fitting an aromatic polycarbonate sheet to a mold, a plurality of pins are provided in a mold, a corresponding positions of the sheet of which are perforated and fitting is performed. In other words, a magnet is buried into a mold, an iron piece is stuck to a position corresponding to the burried position and fitting is performed Then after fitting the sheet, mold clamping is performed. Then a compouded and reinforced polycarbonate molding material is injected and cast through an injection molding machine and the sheet and molding material are laminated and molded integrally. After injection of resin, the molten resin is cooled and solidified and a molded product is obtained after mold release. The sheet and molding material are welded by molding thermally and completely by heat and pressure at the time of molding, and irrespective of a difference in molding shrinkage of respective surfaces, the whole surface is free from a warp and a sheet surface of the molded product possesses excellent external appearance properties.

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 metallic exterior materials of automobiles are heavy and lack the freedom of design, the commercialization of synthetic resin exterior materials is now 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 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.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a synthetic resin molded article such as an automobile exterior material which has excellent surface sharpness and little warpage, and a method for producing the same. is there.

[0004]

The inventors of the present invention have proposed a method (hereinafter sometimes referred to as CFI technology) in which a sheet is mounted in a mold cavity, and another thermoplastic resin is injected and injected to integrally mold the sheet. It was found that the above problems can be solved by utilizing the composite reinforced polycarbonate as a molding material. That is, the present invention is a synthetic resin molded product obtained by an injection molding method, in which an aromatic polycarbonate sheet (A) is cut into a predetermined shape and mounted on one side of a mold cavity, and then a composite reinforced polycarbonate (B) is molded into a metal mold. The invention relates to a synthetic resin molded product (C) obtained by injection-injecting onto the sheet (A) in a mold cavity, and laminating and integrating the sheet (A) and the molding material (B).

The aromatic polycarbonate sheet (A) used in the present invention is 2,2-bis (4-hydroxyphenyl) -propane or 2,2-bis (3,5-dibromo-4).
-Hydroxyphenyl) -propane is a polymer obtained by a known method from one or more divalent phenolic compounds exemplified by propane and a carbonate precursor exemplified by phosgene, and polyethylene terephthalate (PE
It can also be used as a polymer alloy with T), polyesters such as polybutylene terephthalate (PBT), styrene resins, or polyamides.

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 that flows on the sheet is shaped into the product. There is a problem that wrinkles occur because the edges 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. If the thickness of the sheet is preferably 0.3 mm or more, and particularly preferably 0.3 to 3 mm, the appearance of the product at the time of laminate molding is not affected by the glass fiber or glass flakes blended in the core material, and thus the appearance. The property is improved. Further, when the shape is imparted by the above vacuum forming or the like, the shapeability is also excellent. As the above-mentioned sheet, if necessary, a sheet which is preliminarily provided with a character mark by printing, painting or the like, or a sheet which is surface-treated with a thermoformable hard coat or the like can be used.

As the thermoplastic resin used in the composite reinforced polycarbonate molding material (B) used in the present invention, one having a weldability with the aromatic polycarbonate sheet (A) can be used. Specifically, the aromatic polycarbonate is used. ,
Examples thereof include a polycarbonate / polyester resin composition, a polycarbonate / styrene resin composition, a polycarbonate / polyamide resin composition, and other polycarbonate resin compositions (polycarbonate alloy).

The reinforcing filler that can be used in the composite reinforced polycarbonate molding material (B) is compounded in the resin for the purpose of reducing mechanical strength, molding shrinkage or linear expansion coefficient. As the glass, carbon, metal, whiskers, silicon carbide, boron, or other organic / inorganic substances such as fibrous or flake-like materials having the above-mentioned properties are appropriately used. Among the above fillers, glass fiber is particularly desirable. The selection and blending ratio of the above fillers are mechanical strength,
It is determined in consideration of the reduction of the molding shrinkage ratio or the linear expansion coefficient described below.

When the filler and the blending ratio are selected according to the molding shrinkage, the molding shrinkage is determined by using a disk mold having a thickness of 3.2 mm and an outer diameter of 101.6 mm, and the formula 100 × (mold size-molding The value obtained from (product dimension) / (die dimension) is 0.3% or less in the direction parallel to the gate and 0.5 in the vertical direction.
% Or less is desirable. The molding shrinkage ratio is measured under the measuring conditions of a molten resin temperature of 280 ° C. and a mold temperature of 80 ° C., for example, when a polycarbonate mainly containing bisphenol A is used as a composite reinforced polycarbonate molding material. When the molding shrinkage exceeds the above value, each surface of the laminated molded product (sheet surface and material surface)
Because of the large difference in molding shrinkage, warpage may occur over the entire surface of the molded product. Further, when the filler and the blending ratio are selected according to 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 a composite reinforced polycarbonate molding material having excellent mechanical strength and satisfying the above-mentioned molding shrinkage ratio or linear expansion coefficient, for example, glass fiber, glass flakes or a mixture thereof in an aromatic polycarbonate resin composition is used. An example is one containing 50% by weight.
In addition, although a large amount of waste materials such as sprue and runners are usually generated in injection molding, in the present invention, the waste materials are crushed as a part or all of the resin used for the composite reinforced polycarbonate (B) and then the glass fiber is crushed. Can also be used by adding a suitable amount thereof. When the synthetic resin molded product obtained by the present invention is further subjected to coating treatment, the molded product becomes more excellent in surface image clarity. The coating can be usually 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 exemplified below. (1) Mounting the sheet on the mold The aromatic polycarbonate sheet (A) is mounted on the mold by providing a plurality of pins on the mold and making holes at positions corresponding to those of the sheet and mounting it. There are a method and a method in which a magnet is embedded in a mold and an iron piece is attached to 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 polycarbonate molding material (B) is injected and injected from an injection molding machine, and the sheet (A) and the molding material (B) are laminated and 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 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. As the molding processing conditions, the temperature of the molding material is 290
By molding at a temperature of not less than 0 ° C, the fluidity of the resin and the adhesive strength of the sheet can be increased. When using a printed sheet, the mold 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.

[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 image clarity When an object was copied on 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 is as follows. ◯: 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,
The display was 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 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 polycarbonate resin sheet having a thickness of 0.5 mm (hereinafter referred to as
The sheet was punched out by using a press machine according to the size of the die mounting portion (disc shape of 100 mmφ) with a press machine. 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 glass fiber-containing polycarbonate resin material (manufactured by Mitsubishi Gas Chemical Co., Inc.,
Trade name: Iupilon GS-2010M, glass fiber content in composition 10% by weight, molding shrinkage 0.3% in parallel direction, 0.5% in vertical direction, coefficient of linear expansion 5
^{X10 -5} / ° C) was injected. The molding conditions are as follows: resin temperature 300 ° C., mold temperature 70 ° C., injection pressure 1600 kgf
Was / cm ² . Using urethane paint on the molded product,
Spray coating was performed and each evaluation as a product was performed. The evaluation results are shown in Table 1.

Example 2 Polycarbonate resin containing glass fiber (manufactured by Mitsubishi Gas Chemical Co., Inc., trade name: Iupilon GS-2020M, glass fiber content ratio in composition is 20% by weight, molding shrinkage is 0.1 in parallel direction). %, 0.4% in the vertical direction, and a linear expansion coefficient of 4.4 × 10 ⁻⁵ / ° C.).
A molded product was manufactured in the same manner as in 1. and evaluated after coating. The evaluation results are shown in Table 1.

Example 3 A molded product was manufactured in the same manner as in Example 2 except that a 0.3 mm polycarbonate sheet was used, and the evaluation after coating was performed. The evaluation results are shown in Table 1.

Comparative Example 1 Using a polycarbonate resin material similar to that used in Example 2, a non-laminated molded product was prepared under the same conditions as in Example without mounting a sheet, and the sharpness comparison was made. went. The evaluation results are shown in Table 1.

[0020]

[Table 1] Example 1 Example 2 Example 3 Comparative Example 1 Image clarity ○ ○ ○ × Before repeated cooling / heating test 1) Adhesive strength ○ ○ ○ − 2) Warp ○ ○ ○ − After repeated cooling / heating test 1) Adhesive strength ○ ○ ○ − 2) Sled ○ ○ ○ −

[0021]

The integrally molded product obtained by the present invention is
It has excellent image 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 front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical indication location B29L 31:30 (72) Inventor Katsumi Yoshida 5-6-2 Higashihachiman, Hiratsuka-shi, Kanagawa Sanryo Gas Chemical Co., Ltd. Inside the plastic center

Claims (10)

[Claims] 1. A synthetic resin molded product obtained by injection molding, wherein an aromatic polycarbonate sheet (A) is cut into a predetermined shape and mounted on one side of a mold cavity, and then a composite reinforced polycarbonate material (B) is used. Is injected onto a sheet (A), and a synthetic resin molded product (C) obtained by laminating and integrating the sheet (A) and the molding material (B). 2. The synthetic resin molded product (C) according to claim 1, wherein the aromatic polycarbonate sheet (A) has a thickness of 0.3 mm or more. 3. The synthetic resin molded product (C) according to claim 1, wherein the aromatic polycarbonate sheet (A) to be mounted in the mold cavity has been preliminarily given a shape by vacuum molding. 4. The thermoplastic resin used in the aromatic polycarbonate sheet (A) and / or the composite reinforced polycarbonate molding material (B) is a polycarbonate / polyethylene terephthalate resin composition, a polycarbonate / polybutylene terephthalate resin composition, The synthetic resin molded article (C) according to claim 1 or 2, which is at least one or more of a polycarbonate / polyamide resin composition or a polycarbonate / styrene resin composition. 5. The synthetic resin molding (C) according to claim 1 or 2, wherein the composite reinforced polycarbonate molding material (B) is a resin composition comprising at least polycarbonate and glass fibers or glass flakes. 6. A molding shrinkage ratio (thickness: 3.2 mm, outer diameter: 101.6) of the composite reinforced polycarbonate molding material (B).
It is the molding shrinkage ratio when a molded product is obtained using a mm disk mold, and is expressed by the formula: 100 × (mold size−molded product size) /
The synthetic resin molded product (C) according to claim 1 or 2, wherein a value obtained from (die size) is 0.3% or less in a direction parallel to the resin gate and 0.5% or less in a vertical direction. 7. The synthetic resin molded product (C) according to claim 1, wherein the composite reinforced polycarbonate molding material (B) has a linear expansion coefficient of 5 × 10 ⁻⁵ / ° C. or less. 8. A synthetic resin molded product (D) having excellent surface clarity obtained by further coating the synthetic resin molded product (C) according to claim 1 or 2. 9. The molded article is for an automobile exterior material.
The synthetic resin molded article according to any one of claims 1 to 7. 10. A method for producing a synthetic resin molded product by injection molding, comprising cutting an aromatic polycarbonate sheet (A) into a predetermined shape and mounting it on one surface of a mold cavity, and then forming a composite reinforced polycarbonate molding material ( A method for producing a synthetic resin molded product (C) in which B) is injection-injected onto the sheet (A) and the sheet (A) and the molding material (B) are laminated and integrated.