JPH05156051A - Method for plating both sides of frp molding - Google Patents

Abstract

PURPOSE:To obtain a both sides-plated molding having plated layers firmly joined to coating film surfaces by molding an FRP with molds, injecting a specific coating by high pressure while closing the molds to form the coating film and applying ordinary plating to the molding. CONSTITUTION:An FRP is molded by using molds 2 and 3 and a coating in which a material readily etchable by an ordinary plating process is mixed is injected from coating injection inlets 4 and 6 and the coating is applied to the both sides of the FRP to provide a coated molding 1, which is then taken out from the molds. When the molding having firmly bonded with the coating film is plated by ordinary plating process, the coating film is readily subjected to etching treatment to provide the both sides-plated product in which plating layers are firmly bonded on the coating film surface of the FRP both sides.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-sided plating method for FRP molded products.

[0002]

2. Description of the Related Art Plating of thermoplastic ABS resin moldings
Usually, as shown in FIG. 4, it is performed after a chemical etching process is performed in a pretreatment process of plating. However, among the thermoplastic resins, polycarbonate, polymer alloy (modified PPE / PA), etc. are difficult to plate. Therefore, the resin material is blended with a rubber-based material which is easily etched in advance, and then plated. In the process, as shown in FIG. 5, a special etching process is added in the middle of the pretreatment process. However, in a resin molding material that is difficult to plate, since the special etching treatment agent varies depending on the resin component, the process is complicated and a separate line is currently provided in the mass production line.

A sheet molding compound (hereinafter referred to as S), which is a typical molded product of FRP (glass fiber reinforced resin), which has recently come into practical use as an outer panel of an automobile.
Since the molded product obtained by compression molding (MC) is an unsaturated polyester resin as the matrix resin,
In addition to the difficulty in plating, fine holes called pinholes are formed on the surface of the SMC molded product, so even if plating is applied to this surface, the appearance will be poor and the conventional S
It was difficult to put the MC molded product on the surface by plating.

The in-mold coating method (hereinafter referred to as "I") is one of the measures against the pinhole generated on the surface of the SMC molded product.
There is MC). This IMC is a method of painting simultaneously with molding of plastic. The present applicant has previously applied for a patent regarding the invention of the plastic in-mold coating method (Japanese Patent Application No. 1-181778 and Japanese Patent Application Laid-Open No. 3-47).
No. 719).

On the other hand, the plating on the FRP, which is difficult to plate, is carried out by a method in which the FRP surface is pretreated by using a chemical which etches the FRP surface, and then the FRP surface is usually plated, as in the method shown in FIG. There is a method in which a paint which is easily etched in the plating pretreatment process is spray-painted in advance, and then plating is performed in the normal plating process shown in FIG.

The Applicant has used a paint in which a material that is easily etched in a normal plating process is mixed into an IMC paint to form a molded product having a coating film on the surface side of the product,
Next, a patent application was previously filed for an invention in which the molded product is plated by an ordinary plating process (Japanese Patent Application No. 3-126663).
No.)

[0007]

In the method of performing pretreatment using a chemical that etches the FRP surface and then performing plating, as in the process shown in FIG. Must be done, and capital investment will increase. In addition, it is difficult to obtain a paint with good adhesion to both SMC materials and plating materials by the method of spraying paint that is easy to etch in advance and then plating in the usual plating process, so the adhesion of the coating film and plating layer is sufficient. Not satisfied, and the thickness of the spray coating is 20-30μ
6 is a partial cross section of the product, the surface of the coating film d sprayed on the surface of the FRPa molded by SMC becomes orange skin-like and remains in the plated layer e after plating. As a result, a smooth plated surface cannot be obtained, which is clearly inferior to the plated surface of a conventional steel plate.

In the plating method using IMC of the prior invention, only the front surface side of the molded product can be treated, and the back surface side of the molded product leaves the surface of the FRP material without the IMC coating film. When this molded product is subjected to the normal ABS resin plating process, the surface side with the IMC coating film is plated, but the back surface is FRP material and there is no plating, or the adhesion is very poor. It becomes the plated surface. Therefore, the back surface is not suitable for products that require good appearance. Not only that, the FRP exposed on the back surface in the plating process dissolves in the processing liquid, particularly the etching liquid in the chemical plating process to reduce the processing capacity thereof, which causes a decrease in productivity and defective plating. As a solution to this problem, it is possible to coat the fluorine-based resin on the back side of the molded product in advance and run it in the plating process to prevent FRP dissolution, but since the back surface of the product is not plated at all, the following There's a problem. Since the thermal expansion coefficient of the plating layer c adhered to the surface of the plated product 10 shown in FIG. 7A is different from that of FRPa on the back surface side, the shrinkage force of the surface plated layer c causes the shrinkage force of the surface plated layer c in the case of a product having a large thin plate shape as shown in FIG. 7B. As shown, the product is warped, resulting in a defective product.

The present invention solves the above-mentioned problems, and a smooth plating layer is adhered to the front and back surfaces of an FRP molded product by a normal ABS resin plating process with sufficient strength to improve the appearance of the FRP plated product. It is an object of the present invention to provide a double-sided plating method for FRP molded products which has good productivity and can reduce costs.

[0010]

According to the present invention, a mold is used to mold an FRP, and then a material that is easily etched in a normal plating process is mixed into the mold while the mold is closed. FR is used to form a molded product having a coating film on the front and back surfaces by sequentially injecting a coating material onto the front surface and the back surface of the product at high pressure, and then plating the molded product by a normal plating process.
This is a double-sided plating method for P-molded products.

[0011]

The coating material is injected at high pressure while the mold for molding the FRP is closed, and the coating material is caused to flow on the front and back surfaces of the FRP to form coating films on both sides of the molded product. FR taken out of the mold
The sink marks and pinholes generated on the surface of the FRP due to the strong adhesion of the coating film on both sides of the P-molded product are filled with the paint, and the surface becomes smooth. When this FRP molded product is treated in a normal plating process, the coating film contains a material that is easy to process in the etching process of the normal plating process, so it is easily etched, and the plating layer formed in the plating process is The surface of the plating layer is smooth and the surface of the plating layer is smooth.

[0012]

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view of an IMC mold for an automobile panel. The molded product 1 has a tab 1 which serves as a paint inlet for the surface side.
a is formed. In the mold for molding the molded product 1, a cavity having a shape corresponding to the molded product is formed between the upper mold 2 and the lower mold 3 of the split mold, and the upper mold 2 for molding the surface side of the molded product 1 is
A paint injection port 4 that opens to the formation portion of the tab 1a and a nipple 5 that connects an exhaust hole provided on the opposite side to a vacuum pump are provided. An inlet 6 and a pressure sensor 7 are installed. 8 is a seal, 9
Is a temperature control circuit provided in each of the upper and lower molds.

Next, the IMC using the mold shown in FIG.
The molding process will be described with reference to FIG. The SMC material is placed on the lower mold 3, the upper mold 2 is closed, and the SMC material is hardened by maintaining the molding pressure P1 of 70 to 80 kg / cm ² for a prescribed time T1. After the SMC material has hardened, once the molding pressure is increased to P2 (2
(0 kg / cm ² ) to lower the air inside the mold from the exhaust hole to 2
Drain for ~ 3 seconds. Next, the IMC paint, which was made easy to be etched in the usual plating process, was injected from the upper mold injection port 4 at the position of the tab 2 at a high pressure of 300 kg / cm ² (I1).
Then, after injecting the paint, the molding pressure is P3 (about 40 kg / cm ² )
And hold for several seconds (T2) to allow the paint to flow on the surface of the molded product. After that, the molding pressure is changed to P4 (0 to 20 kg
/ Cm ² ), IMC paint similar to the above is injected from the lower paint injection port 6 at a high pressure of 300 kg / cm ² (I 2), and after injection of the paint, the molding pressure is raised to P 3 again for several seconds ( T3)
The paint is allowed to flow on the back surface of the molded product by holding it, and then the molding pressure is again lowered to 0 to ²⁰ kg / cm ² , and the paint is cured by being kept in this state for a prescribed time.

As described above, if the inside of the mold is evacuated while the mold is closed before the paint is injected, air cannot be accumulated in the mold when the paint is injected, and the paint is injected into the mold. The coating material is preferable because it flows well on the surface of the cured SMC due to an increase in molding pressure and a good coating film can be stably obtained, but depending on the shape of the molded product, evacuation is not always necessary. As the IMC paint, a base resin blended with a urethane acrylate oligomer or the like and a component such as calcium carbonate as a filler which is easily etched is used.

The molded product taken out of the mold is an FRP molded by SMC as shown in FIG. 3 which is a partial cross section of the product.
The IMC coating film b having a thickness of 70 to 100 μm is firmly adhered to both surfaces of a, and the pinhole generated on the surface of the FRP is IM
It is filled with C paint and its surface becomes smooth. This is processed by the normal plating process shown in FIG. This FRP
The IMC coating film b is easily processed by the chemical etching process of the normal plating process, so that the plating layer c is formed on both sides of the IM film.
While being firmly adhered to the C coating film b, the surface of the plating layer c becomes smooth, and the appearance is as good as or better than the plating surface of the conventional steel sheet. In the above embodiment, the lower mold paint injection port is provided so as to be directly opened to the molding portion, but it may be provided at a position where it is injected into the tab attached to the molded product.
If the back surface shape of the molded product is flat, the flow of the IMC paint is good, and the lower mold paint injection port can be installed at any position.

Further, a headlamp reflector of an automobile
Is currently the bulk molding compound (hereinafter BM
It is manufactured by subjecting a light reflecting surface of a reflector injection-molded using (C) to aluminum vacuum deposition. BM
C is a molding material in which a chopped strand of glass fiber is mixed or impregnated with an unsaturated polyester resin mixed with a curing agent and a condensing agent, and further gelled, which has higher heat resistance than other molding materials. (200 ° C) Moreover, since the curvature of the light reflecting surface can be freely changed, it is suitable for forming a reflector. The present invention is not limited to SMC molded products,
It can be applied to a molded product made of BMC, and the plated layer on the surface of the product becomes smooth and the plated layer is formed on the back surface, so that the deformation of the product due to heat can be suppressed.

[0017]

INDUSTRIAL APPLICABILITY The present invention provides IMC on both sides of a FRP molded body.
The coating film is firmly adhered, and a smooth plating layer is attached to it with sufficient strength by a normal plating process, which improves productivity and improves the appearance of FRP products, and plating that does not cause deformation. The product is obtained.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a mold for IMC used in the present invention.

FIG. 2 is an explanatory view of a molding process of the present invention.

FIG. 3 is a partially enlarged sectional view of a product manufactured by the method of the present invention.

FIG. 4 is a diagram showing a conventional normal plating process.

FIG. 5 is a diagram showing a conventional special plating process.

FIG. 6 is a partially enlarged sectional view of a product manufactured by a conventional method.

FIG. 7 is a sectional view of a single-sided plated product.

[Explanation of symbols] 1 Molded product 1a Paint injection tab 2
Upper mold 3 Lower mold 4,6 Paint injection port 7 Pressure sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sohou Hasegawa 8 Tsutana, Fujisawa City, Kanagawa Prefecture Isuzu Central Research Institute Co., Ltd. Central Research Institute (72) Inventor Takashi Fujita 8 Isuzu Central Research Institute, Fujisawa, Kanagawa Prefecture Isuzu Central Research Institute (72) Inventor Ryomitsu Suyama 8 Tsuchitan, Fujisawa City, Kanagawa Isuzu Central Research Institute (72) ) Inventor Tokiko Ohori 8 Tsutana, Fujisawa City, Kanagawa Prefecture, Isuzu Central Research Institute

Claims (1)

[Claims] 1. A FRP is molded using a mold, and then a paint containing a material that is easily etched in a normal plating process is mixed into the mold while the mold is closed under high pressure. And a method for double-sided plating of an FRP molded article, which comprises successively injecting into the back surface side to form a molded article having a coating film on the front and back surfaces, and then plating the molded article by a normal plating process.