Coating processes – Solid particles or fibers applied
Reexamination Certificate
2000-04-26
2002-04-02
Parker, Fred J. (Department: 1762)
Coating processes
Solid particles or fibers applied
C427S242000
Reexamination Certificate
active
06365224
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for forming, on the surface of a resin molded product, a metal layer which is useful for forming a metal film. More particularly, the present invention relates to a process for forming, on the surface of a resin molded product, a metal layer of a fine metal powder produced by bringing a metal powder producing material into flowing contact with the surface of the resin molded product in a treating vessel.
2. Description of the Related Art
For the purpose of providing, to a resin molded product, various properties such as an ornamentality, a weather resistance, a surface electrical conductivity, an electromagnetic wave shielding property, an antibacterial property and the like, it is a conventional practice to form a metal film on the surface of the resin molded product. Examples of conventionally known processes for forming a metal film are a vacuum plating process such as a vacuum deposition and a sputtering, an electroless plating process, an electroless plating/electroplating process comprising an electroless plating step and an electroplating step, and the like. These processes have been put into practical use in various fields, because an electroplating process cannot be applied directly to the resin molded product due to the non-electrical conductivity of the resin molded product.
However, the vacuum plating process suffers from problems that a metal film formed by this process has a lower peel strength and a poor durability, that it is difficult to apply this process to a molded product having a complicated shape, that a long time is required for the vacuum processing, because a gas may be generated depending on the type of a resin, and that a production cost is higher.
The electroless plating process suffers from the following problems: It is usually necessary to previously subject the surface of a resin molded product to an etching, or to subject the surface to a catalytic effect providing process such as a sensitizing/activating process. For this reason, the steps are complicated; a long time is required for the processing; and a plated film produced has a small thickness.
In the electroless plating/electroplating process, a metal film formed by this process has a relatively good peel strength, and a durability which is remarkably good, as compared with that of a metal film formed by the vacuum plating process. However, the electroless plating/electroplating process suffers from problems that the steps are complicated, and that a long time is required for the processing.
There is also a proposed metal film forming process comprising a step of applying a resin including a metal powder added thereto to the surface of a resin molded product to provide an electrical conductivity to the surface of it, and an electroplating step. However, this process suffers from a problem that it is generally difficult to provide a resin layer uniformly on the surface of a resin molded product and for this reason, it is impossible due to the ununiformity of the resin layer to form a metal film excellent in thickness accuracy and in surface smoothness.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a process for forming, on the surface of a resin molded product, a metal layer which is useful for forming a metal film having an excellent thickness accuracy, an excellent surface smoothness and a high peel strength on the surface of the resin molded product in a simple manner.
The present inventors have made various studies to solve the above problems and as a result, they have found that if a fine metal powder producing material is brought into flowing contact with the surface of a resin molded product in a treating vessel, a fine metal powder is produced from the fine metal powder producing material and forms a firm and high-density metal layer on the surface of the resin molded product. It has been further found that the thus-formed metal layer exhibits a function as an electrically conductive layer and hence, a metal film can be formed in a simple manner on the surface of the resin molded product by conducting an electroplating at a subsequent step, and that the metal layer itself exhibits a function of an ornamentality and the like.
The present invention has been accomplished based on such knowledge. To achieve the above object, according to a first aspect and feature of the present invention, there is provided a process for forming a metal layer on the surface of a resin molded product, comprising the steps of placing a resin molded product and a fine metal powder producing material in to a treating vessel, and bringing the fine metal powder producing material into flowing contact with the surface of the resin molded product in the treating vessel, thereby producing a fine metal powder from the fine metal powder producing material, and forming a metal layer of the fine metal powder on the surface of the resin molded product.
According to a second aspect and feature of the present invention, in addition to the first feature, the fine metal powder producing material is brought into flowing contact with the surface of the resin molded product by applying a vibration and/or an agitation to the resin molded product and the fine metal powder producing material.
According to a third aspect and feature of the present invention, in addition to the first feature, the treating vessel is a treating chamber in a barrel finishing machine.
According to a fourth aspect and feature of the present invention, in addition to the first feature, the processing is carried out in a dry manner.
According to a fifth aspect and feature of the present invention, in addition to the first feature, the fine metal powder producing material is a material for producing a fine powder of at least one metal selected from the group consisting of Cu, Sn, Zn, Pb, Cd, In, Au, Ag, Fe, Ni, Co, Cr and Al.
According to a sixth aspect and feature of the present invention, in addition to the first feature, the surface of the resin is previously roughened at a pre-step.
According to a seventh aspect and feature of the present invention, there is provided a process for forming a metal film on the surface of a resin molded product, comprising the steps of forming a metal layer on the surface of a resin molded product according to any of the first to sixth features, and forming a metal film on the metal layer.
According to an eighth aspect and feature of the present invention, in addition to the seventh feature, the metal film is formed by an electroplating treatment or an electroless plating treatment.
According to a ninth aspect and feature of the present invention, there is provided a resin molded product which has a metal layer of a fine metal powder on the surface thereof.
According to a tenth aspect and feature of the present invention, there is provided a resin molded product which has a metal layer of a fine metal powder formed on the surface thereof, and a metal film formed on the metal layer.
With the process for forming a metal layer according to the present invention, a metal layer of a fine metal powder can be formed at a firmly and a high density on the surface of the resin molded product. The metal layer exhibits a function as an electrically conductive layer and hence, a metal film having an excellent thickness accuracy, an excellent surface smoothness and a high peel strength can be formed in a simple manner on the metal layer by conducting an electroplating treatment. In addition, it is possible for the metal layer itself to exhibit a function of an ornamentality and the like.
DETAILED DESCRIPTION OF THE INVENTION
The process for forming a metal layer on a resin molded product according to the present invention comprises the steps of placing a resin molded product and a fine metal powder producing material into a treating vessel, and bringing the fine metal powder producing material into flowing contact with the surface of the resin molded product in the treating vessel, thereby pr
Kikui Fumiaki
Nishiuchi Takeshi
Tsujimoto Shuji
Yoshimura Kohshi
Armstrong Westerman & Hattori, LLP
Parker Fred J.
Sumitomo Special Metals Co. Ltd.
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