JPH0681167A - Formation of metallic film on formed body made of synthetic resin - Google Patents

Abstract

PURPOSE:To form a metallic film free from defects at low cost by forming a low m.p. metallic film on the surface of a formed body made of synthetic resin by a physical method, coating the surface with flux, executing heating and remelting the surface of the metallic film. CONSTITUTION:A coarse metallic film 2 is formed on the whole body or a part of the surface of a formed body made of synthetic resin by physical metallic film forming means. As for this coarse metallic film 2, a metal having the m.p. lower than the heat resisting temp. of the formed body 1 is used. Furthermore, as the physical means, thermal spraying or ion plating is suitably used. Next, the surface of this coarse metallic film 2 is coated with flux, and the formed body 1 is heated to the vicinity of the m.p. of the metal. Or, the formed body 1 may be immersed in the bath of the flux heated to the vicinity of the m.p. of the metal. In this way, the surface of the coarse metallic film 2 is remelted to form the metallic film 3 free from defects such as pin holes and cracks.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic resin having a metal coating, which is excellent in permeation barrier properties against gas and liquid and is suitable for use in a synthetic resin high airtight container, a synthetic resin vacuum heat insulation container, or the like. The present invention relates to a method for forming a metal film on a molded body.

[0002]

2. Description of the Related Art Conventionally, as a vacuum heat insulating container such as a thermos or a heat retention lunch box, a glass or metal heat insulating container is used instead of the vacuum heat insulating container.
A vacuum insulating container made of synthetic resin that is lightweight and easy to mold has been provided. The vacuum heat insulating container made of synthetic resin is configured such that the inner cylinder and the outer cylinder are joined and integrated at respective mouth portions, and the space between the inner and outer cylinders is formed as a vacuum heat insulating layer. On the outer surface of the inner cylinder and the inner surface of the outer cylinder made of a synthetic resin used as a heat insulating container of this kind, a metal film having an excellent permeation blocking property against gas or liquid is formed and used. And conventionally, as a method of forming a metal film on a synthetic resin molded body such as the inner and outer cylinders of the synthetic resin vacuum heat insulating container,
Electroless plating and electroplating are mainly carried out. Further, thermal spraying, ion plating, etc. are known as physical methods for forming a metal film.

[0003]

However, in electroless plating and electroplating, many steps such as etching are required as a pretreatment, and various chemicals such as chromic acid must be used and discarded. did not become. Then, after the pretreatment, it was necessary to carry out a plating treatment so as to form a metal film up to at least 10 μm in order to give a permeation blocking property, and it took a considerable time. Further, when a physical metal film forming method such as thermal spraying or ion plating is carried out, it is difficult to form a metal film having an excellent permeation blocking property due to many defects such as pinholes and cracks. It was From the above,
Under the current circumstances, it is impossible to inexpensively form a metal film having excellent permeation-blocking properties against a gas or a liquid on a synthetic resin molded body. Further, in the conventional method for forming a metal film of a synthetic resin molded body, a metal having a relatively high melting point is used for forming the metal film, so that the solderability is poor and it is difficult to join it to other parts.

The present invention has been made to solve the above problems, and an object thereof is to reduce the manufacturing cost by forming a metal film on a synthetic resin molded body in a short time in a small number of steps. is there. A further object of the present invention is to provide a synthetic resin molded article having a metal coating that has an excellent permeation barrier property against gas and liquid. Further, the present invention has good solderability,
It is an object of the present invention to provide a synthetic resin molded product having a metal film, which can be easily joined to other parts.

[0005]

In order to solve the above-mentioned problems, the invention described in claim 1 is a metal having a melting point lower than the heat resistant temperature of the molded body on all or part of the surface of the molded body made of synthetic resin. To form a metal film by a physical metal film forming means, then apply a flux to the surface of the metal film, and then heat the formed body on which the metal film is formed to near the melting point of the metal. It is characterized by remelting the surface of. In the invention described in claim 2, a metal film is formed on all or part of the surface of the synthetic resin molded body by a physical metal film forming means by using a metal having a melting point lower than the heat resistant temperature of the molded body, Then, the molded body having the metal coating formed thereon is immersed in a flux bath heated to near the melting point of the metal to remelt the surface of the metal coating. Further, as the means for forming the physical metal film, the thermal spraying or the ion plating method as described in claims 3 and 4 is preferably used.

[0006]

The method of forming a metal film on the synthetic resin molded body of the present invention has fewer pretreatment steps than the plating method. Further, in the method for forming a metal film of a synthetic resin molded body of the present invention, by heating the molded body to the melting point of the low melting point metal after forming the metal film, only the surface of the metal film coated with the flux is remelted. Therefore, defects such as pinholes and cracks are filled and repaired.

[0007]

EXAMPLE A method for forming a metal film on a synthetic resin molded article according to the present invention will be described in detail below with reference to FIG.

FIG. 1 (a) shows a synthetic resin molded body 1 before the crude metal film 2 is formed. As the material of the synthetic resin molded body 1 preferably used in the present invention, a synthetic resin material such as a polycarbonate resin, a polysulfone resin, a heat-resistant ABS resin or the like is preferably used. These synthetic resin materials are used after being molded into a desired shape such as a tubular body by a molding method such as injection molding or blow molding.

Next, a crude metal film 2 is formed on a part or all of the surface of the molded synthetic resin molded body 1 as shown in step (b) of FIG. The material metal of the crude metal film 2 is a low-melting metal whose melting point is lower than the heat resistant temperature of the synthetic resin molded body 1, and considering the usage state of the synthetic resin highly airtight container or the synthetic resin vacuum heat insulation container, The melting point of this metal is preferably 100 ° C. or higher. Therefore, as a low melting point metal suitable for forming the crude metal film 2, 55.5Bi-44.5Pb (melting point 124
℃) and 57.42Bi-41.58Sn-1Pb (melting point 135 ° C).

Before forming the crude metal film 2 on the synthetic resin molded body 1, all or part of the surface of the synthetic resin molded body 1 is subjected to pretreatment such as blasting to increase the adhesion strength of the crude metal film. It is desirable to increase it. As a method for forming the crude metal film 2, a physical metal film forming means such as thermal spraying or ion plating is used. An example of this thermal spraying method is an arc spraying method in which a metal is melted and jetted using an arc spray gun. As shown in FIG. 1B, the crude metal film 2 formed by such a physical metal film forming means has many defects such as pinholes and cracks.

Next, a flux is applied to the crude metal film 2 formed on the surface of the synthetic resin molded body 1 to form the crude metal film 2.
Prevents surface oxidation. As the flux used here, a water-soluble organic acid-based flux is preferable. Examples of the water-soluble organic acid-based flux include a mixed solution of organic acids (stearic acid, malonic acid, succinic acid, etc.), water, and an additive.

Next, as shown in FIG. 1 (b), the synthetic resin molding 1 having the rough metal coating 2 formed on the surface thereof is subjected to a heat treatment to a temperature close to the melting point of the metal so that the surface of the rough metal coating 2 is removed. Remelt. This heating method is preferably a heating method using an inert gas such as N2 gas in order to prevent reoxidation of the crude metal film 2. In this case, it may be heated with hot air of N2 gas, or may be heated in a furnace filled with N2 gas.

By performing the remelting treatment of the crude metal film 2 as described above, defects such as pinholes and cracks in the crude metal film 2 are repaired, and a homogeneous metal film 3 is formed as shown in FIG. 1 (c). It is formed. The synthetic resin molded body 1 on which the homogeneous metal film 3 is formed has an excellent permeation barrier property against liquids and gases. Further, since this metal film forming method has a smaller number of steps than the conventional plating method, the cost for forming the metal film can be significantly reduced. Further, a synthetic resin molded body 1 on which a metal film 1 is formed by the method of the present invention
Has a low melting point metal film 1, so that the solderability is good, and the joining with other parts is easy.

Next, another example of the method of the present invention will be described. In this example, as in the previous example, a physical metal film forming method is used on the surface of the synthetic resin molded body 1 to form a rough metal film 2 having pinholes and cracks as shown in FIG. 1B.
In this example, the synthetic resin molded body 1 on which the crude metal film 2 is formed is not coated with flux, but is immersed in a flux bath heated to near the melting point of this metal to form the crude metal film 2.
Re-melt the surface of. The water-soluble flux used here is the same as the flux in the above-mentioned example.

By such heat treatment in the water-soluble flux bath, defects such as pinholes and cracks in the crude metal film 2 are repaired. With the metal film forming method according to this example, the same effects as in the previous example can be obtained.

(Production Example) An outer cylinder and an inner cylinder of a vacuum heat insulating container are manufactured by injection molding using a polycarbonate resin as a material. Next, after spraying small particles of aluminum oxide on the inner surface of the outer cylinder and the outer surface of the inner cylinder using a blasting device, the low melting point metal (55.5Bi-45.5Pb, melting point 124 ° C) is melted using an arc spray gun. While spraying, a film having a film thickness of 20 to 30 μm is formed. Next, a water-soluble organic acid-based flux was sufficiently applied to each of the outer cylinder and the inner cylinder,
Only the surface of the low melting point metal film is remelted by heating to N ° C with hot air of N ₂ gas.

By manufacturing a vacuum insulation container made of synthetic resin by using the outer cylinder and the inner cylinder obtained as described above, the conventional metal-made one and the proposed synthetic resin-made one are manufactured. The manufacturing cost can be reduced as compared with the above. Further, in the obtained vacuum insulation container made of synthetic resin, defects such as pinholes and cracks are repaired by the remelted metal, and therefore, the permeation barrier property against gas and liquid is excellent. Further, since the low melting point metal is used as the metal film, the solderability becomes good, and the joining with other parts is easy.

[0018]

Industrial Applicability The method for forming a metal film on a synthetic resin molded article of the present invention is a physical method such as thermal spraying or ion plating using a metal having a melting point lower than the heat resistant temperature of the synthetic resin molded article. A method of forming a metal coating on all or part of the molded body, applying flux to the entire surface of the metal coating, and then heating the molded body to the melting point of the metal to remelt only the surface of the metal coating. Therefore, defects such as pinholes and cracks in the metal film are repaired, and the synthetic resin molding having the metal film has an excellent permeation barrier property against liquids and gases. In addition, since the method for forming a metal film on the synthetic resin molded body of the present invention has a smaller number of steps than the conventional plating method, the cost for forming the metal film can be significantly reduced. Further, since the synthetic resin molded body having the metal coating formed by the present invention has the low melting point metal coating, the solderability becomes good and the joining with other parts becomes easy.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a synthetic resin molded article for explaining an example of a method for forming a metal film according to the present invention in the order of steps, FIG. 1A is a state before a metal film is formed, and FIG. Shows a crude metal film forming step, and (c) shows a metal film forming step.

[Explanation of symbols]

 1 Molded body made of synthetic resin 2 Crude metal film 3 Metal film

Claims (4)

[Claims] 1. A metal film is formed on all or part of the surface of a synthetic resin molded body by a physical metal film forming means using a metal having a melting point lower than the heat resistant temperature of the molded body, and then the metal film is formed. Forming a metal film on a synthetic resin molded body characterized by applying flux to the surface and then heating the molded body on which the metal film is formed to near the melting point of the metal to remelt the surface of the metal film. Method. 2. A metal film having a melting point lower than the heat resistant temperature of the molded body is used to form a metal film on all or part of the surface of the molded body made of a synthetic resin by a physical metal film forming means, and then the metal is formed. A method for forming a metal film on a synthetic resin molded body, characterized in that the molded body on which the metal film is formed is immersed in a flux bath heated to a temperature near the melting point to remelt the surface of the metal film. 3. The method for forming a metal film on a synthetic resin molded article according to claim 1, wherein the physical metal film forming means is thermal spraying. 4. The method according to claim 1, wherein the physical metal film forming means is an ion plating method.
7. A method for forming a metal film on a synthetic resin molded body according to 1.