JPH0737671B2 - A method for producing a resin molded product, wherein one surface is electrolessly plated and the non-plated surface is processed to have a satin finish. - Google Patents

Description

Detailed Description of the Invention

(Regarding the meaning of plating) In the present specification, "plating" means to attach a very thin metal film to an object, and not only electroplating but also silver mirror reaction or vapor deposition, Including metallikon, etc., and also includes a method of chemically reducing metal ions to deposit a metal film on the surface of the article, etc.
Plating that does not rely on electrolysis is called electroless plating, and plating on only one of the front surface and the back surface of an article or what leaves the plated surface is called single-sided plating. And the plating which combined electroless plating and single-sided plating is called single-sided electroless plating.

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin molded product in which a resin molded product is subjected to electroless plating on one side and the non-plated surface is processed to have a satin finish.

[0003]

2. Description of the Related Art Plating is used to cure, protect, make cosmetic, mirror-finish, improve wear resistance and lubricity of an article surface, make it electrically conductive, form an electric circuit, prevent leakage of interference electromagnetic waves from the inside of electronic equipment, or It has been widely used since it has functional features such as protection against malfunction of electronic devices due to electromagnetic waves from the outside. Particularly in recent years, along with the development of electronic parts, their high functionality has been applied together by combining them with the material of plated articles.

With the development of electronic equipment, electroless plating applied to resin molded parts of electronic equipment has been developed in the United States to prevent leakage of electromagnetic waves generated from electronic equipment and to prevent malfunction due to interfering electromagnetic waves. In the spotlight as "shield plating", it has come to be widely used in parts such as resin housings of electronic devices in Japan. Among electroless plating,
Metal films such as Cu, Ag, Zn, and Ni have an effect of shielding electromagnetic waves, and a Cu plating film having a thickness of only a few μm has a feature of suppressing passage of electromagnetic waves. Taking advantage of this feature, plating combined with electroless Ni plating that also has the purpose of rust prevention of electroless Cu coating,
Most commonly used as "electromagnetic wave shield plating".

As the "electromagnetic wave shield plating", electroless plating is generally used in many cases, and there are a method of plating on both sides of a housing which is a resin molded product and a method of plating on only one side. The method of plating on both sides has a high shielding effect and is most commonly used for shielding purposes. However, even though a sufficiently effective shield effect can be obtained on one side, the demand for single-sided plating has risen suddenly because the coating on double-sided plating has poor adhesion.

By the way, the method of plating on one side is generally classified into two methods. One is a method of coating only one surface of a resin molded part by applying a paint that does not plate on one surface as a masking, and is called a resist method. The other is a method called a primer method in which plating is applied only to the surface coated with a paint in order to apply plating. (For example, US Pat.
76,841, 5,120,578 and 4,66
No. 3,240).

(Process by Conventional Method) Resin Molded Parts,
For example, two methods of performing single-sided plating on the housing of a personal computer, which is the most representatively used "electromagnetic wave shield plating" technology, will be described. In the resist method, a paint for resist is applied as a masking to a portion where plating is not applied in advance in a coating factory and dried. Next, it is put into a plating line and subjected to electroless copper or electroless nickel plating. Then, it is washed with water and dried, and the plating film is deposited only on the portion where the resist coating material is not applied. As a result, the single-sided plating is completed.

In the primer method, a paint containing a catalyst necessary for depositing a plating is first applied in a paint shop and dried. After that, it is put into a plating line and subjected to electroless copper and electroless nickel plating. Then, wash with water and dry, only the part where the primer is applied,
The plating film is deposited and the single-sided plating is completed. In both the resist method and the primer method, a complicated masking jig must be manufactured in advance, the jig must be installed, the resist or the primer coating must be applied, and the material must be sufficiently dried before the article is put into the plating process. It is a common feature of conventional methods that this coating process must be incorporated as a pretreatment step.

[0009]

In the conventional one-sided plating method in which the coating process is incorporated as a pretreatment step, the cost is increased because a special paint is applied, and a masking jig for coating is required. Since it has to be specially manufactured and incorporated into the manufacturing process, there is a cost problem that the manufacturing cost cannot be realized in proportion to the plating area despite the fact that the plating is provided on only one side. Also,
Not only does the manufacturing process increase due to the application of paint,
There is a problem in productivity that it takes an extra long time to completely dry the paint, and the production efficiency and mass productivity are low.

In the case of the resist method, since the resin surface immediately after molding after plating is exposed, it was difficult to obtain commercial quality without coating as surface treatment. In other words, since the weld line and flow mark generated at the resin molding stage are still exposed on the unplated resin surface, in order to obtain a better finished appearance, after all steps, , It was necessary to apply cosmetic coating on the surface of the exterior part that had no plating.

On the other hand, the primer method has a problem that the catalyst may not react sufficiently during the plating process because the coating material contains a catalyst for precipitating the plating. The thickness of the film is not constant and may occasionally vary. This had a quality problem of causing a somewhat unstable effect on the shield effect. In addition, in the case of complicated shapes such as deep intricacy or projections such as snap joints, it is difficult to apply plating because the paint is not applied to every corner. .

In addition to these problems of cost, productivity and quality, the number of such workers has decreased in recent years despite the need for skilled engineers for such a painting process, and the number of skilled workers will be enhanced in the future. There is also a human problem that it will be difficult to make them do. In addition, even after being washed with water and dried after being taken out of the plating solution, it is rare that acidic or alkaline chemicals remain near the boundary between the plated deposition surface and the non-plated surface of the dried article. There were also cases where the plating film rusted or corroded earlier than expected.

When it is necessary to cosmetically coat the exterior part of the non-plated surface, the residual chemical rarely causes the paint to completely adhere and the coating film thickness cannot be made uniform. In some cases, the peeling of the coating easily occurred and the resin cracked. Further, in both the resist method and the primer method, the material of the resin that can be electrolessly plated on one side is limited, and the fact that the electroless plating on both sides allows the one-sided plating not to be possible.

Since the present invention can eliminate the step of applying paint before plating, it is a relatively simple blasting method than applying the paint used for the conventional process without using an expensive special paint. By incorporating the process into the process immediately after plating, it enables single-sided electroless plating for all resins that can stably deposit double-sided electroless plating, reducing the cost and number of processes, improving production efficiency, and improving production technology. The purpose of the invention is to manufacture a resin molded product in which the non-plated surface is matte-finished and the plated surface is single-sided electroless-plated by solving problems, satisfying human factors and using different cleaning agents.

[0015]

In order to achieve the above object, in the manufacturing process of the present invention, the article is first completely immersed in a plating solution as in the prior art, and plating treatment is applied to both sides, and then a drier is used. Pass through. Next, as one-sided plating, the side for leaving the plated surface is covered and covered with a jig for masking, and the opposite surface is sprayed with compressed air mixed with granular or powdery gold steel sand or the like. By this blasting, one plating surface is peeled off and the resin surface is exposed.
A non-plated resin surface that is not satin-finished is formed by shot-blasting a different abrasive cleaning material than the one used in the previous blasting process onto the resin surface. Molded products can be made.

(Example of Manufacturing Process According to the Present Invention) First, a resin molded product is put into a normal double-sided plating line. Generally, electroless copper and electroless nickel plating is applied on both sides, followed by washing with water and drying. Next, as one side plating,
Cover the side where the effective plating surface is left with a jig for masking. On the opposite side, a blasting material such as aluminum oxide in the form of granules or powder or gold steel sand such as glass beads is blown together with compressed air by shot blasting. By this blasting, one plating surface is peeled off, the residual chemical is removed, and the resin surface is exposed. Thereafter, the blasting treatment is further changed and the blast treatment is continuously performed to change the texture and color tone of the exposed resin surface.

[0017]

Since the present invention is constructed as described above, it has the following effects. According to the present invention, in the conventional single-sided plating, the number of resins that can be plated was limited to a small number because of the characteristics of the process and problems in the production technology, but the first process is the same process as the double-sided electroless plating. Therefore, the number of resins that can be plated is overwhelmingly larger than that of the conventional method. Then, since the expensive coating material for the resist or the primer is not used in the coating process of the pretreatment of the plating which is always necessary at the beginning, the single-sided plating can be realized at a much lower cost. Even for the masking jig that was absolutely necessary to apply this paint, it is possible to omit the equipment and personnel who have both advanced coating technology and masking jig manufacturing technology.
It is possible to contribute to improvement of mass productivity such as reduction of cost and number of steps, reduction of required time.

Originally, one of the main reasons why the demand for single-sided plating has risen from the most commonly used double-sided plating is that the coating on the exterior surface is easily peeled off. When it is necessary to paint, in addition to being able to easily paint, the coating film becomes difficult to peel off, and various types of paint can be used. By the way, in the primer method, if the shape is complicated and has a complicated shape such as a projection like a snap joint designed as a joining point, the coating will not be applied to every corner, so plating should be applied. However, because double-sided electroless plating is used in the first step, it is possible to make resin-molded parts with a single-sided electroless plating film even for molded products with complicated shapes. It will be possible.

As a result, good adhesion of the plating film to the resin and high conductivity on the plating film can be realized,
Not only can we manufacture articles that can control conductivity and shielding effects more strictly, but we can also make effective use of snap joints, etc. used in the joints of parts, eliminating the need for screwed joints, etc. It is possible to reduce the weight as much as possible, reduce costs, and improve productivity when assembling parts.

By incorporating the shot blast, which is the greatest feature of the present invention, in the process, not only a single-sided plated surface can be realized, but also rarely, it cannot be completely removed in the cleaning step of the plating process. The acidic and alkaline chemicals remaining on the surface can be completely removed from the resin surface exposed by peeling the plating film, making it possible to manufacture single-sided plated parts with higher quality and higher perfection. Become. In addition, shot blasting can erase flow marks and weld lines, eliminating the need for extra makeup painting and making the most of the color and tone of the resin itself. In addition, shot blasting can not only make the resin surface exposed by peeling the plating film into a satin finish that gives an astringent feel, but also change the color tone and gloss of the satin finish by changing the blasting and cleaning material. be able to.

Even when the resin surface exposed by the blast treatment is cosmetically coated, residual chemicals in the plating process can be completely removed before coating, so that the coating film is not affected by the chemicals and the quality is stabilized. Will be easier. Since the above is realized, a higher quality single-sided electroless plated article can be manufactured in a shorter time at a low cost.
Further, it is possible to similarly manufacture a resin molded product having a non-plated surface which is further subjected to electroless plating on one side and has a satin finish.

Claims (2)

[Claims] 1. After plating the entire front and back surfaces of a resin molded product, a surface where the plating is not removed is covered with a masking, and the unmasked surface is shot blasted to form granular or powdery aluminum oxide or By using a method of blowing a polishing agent such as gold steel sand such as glass beads together with compressed air, the plating film and residual plating agent on one side are peeled off, and one side is electroless plated and the non-plated surface becomes matte. A method of manufacturing a resin molded product to be processed. 2. The resin molded article produced according to claim 1 is continuously blasted with different abrasives to change the texture and color tone of the matte surface of the non-plated surface. A method for producing a resin molded product, which is electroless plated and the non-plated surface is processed to have a satin finish.