JP2001106816A - Surface treatment of plastic molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for surface-treating a plastic molding to form a product having a high surface hardness and beautiful appearance. SOLUTION: A primer layer 2, a hard-coat layer 3, a vapor-deposited metallic film layer 4, and a metal or metal compound layer 5 formed by ion plating are formed on a plastic molding 1 in the given order. Owing to the presence of the layer 4, the ion plating layer can soundly develop to form a beautiful coating film. In an embodiment, the layer 4 is constituted from at least one member selected from Ti, Cr, Ta, Al, V, and Zr and has a thickness of 0.01-1 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface-treated plastic molded product having a high hardness and abrasion resistance and a beautiful texture of a glossy or matte surface of a metal. It also relates to the manufacturing method.

[0002]

2. Description of the Related Art Plastics are used in the manufacture of various parts because of their advantages such as high moldability, light weight, and relatively low cost. There are limitations such as being low and easy to be scratched, and not being so beautiful in appearance. Although the appearance can be improved by applying a coating, the surface properties such as hardness cannot be enhanced even by this.

Various surface treatment techniques have been developed to cover this point. For example, metal plating such as chromium plating is currently implemented as an effective means. In the case of chromium plating, usually, first, electroless plating is performed on a plastic molded product, the surface is coated with copper, nickel, zinc, etc., and chromium electrolytic plating is performed using the obtained conductive coating. I follow the procedure.

[0004] However, electrolytic plating, especially chromium plating, is considered to be difficult to implement in the near future due to environmental problems, and alternative techniques are required. Attention is drawn to dry surface treatment techniques such as metal deposition and ion plating. However, metal deposition
Simply forming a metal film on the surface of a plastic molded article is effective in achieving a metallic luster, but the thickness of the film that can be formed under practical operating conditions is limited, It is not very useful for improving the surface hardness.

On the other hand, ion plating can form a coating of an extremely hard substance such as a metal nitride or carbide, and thus can sufficiently satisfy the requirement of increasing the surface hardness. The above-mentioned metal compounds have colors exceeding the inherent colors of metals such as gold, black, and brown, and can also produce a mixed color thereof, thereby giving a variety of appearance products. be able to.

However, in the conventional ion plating, since the processing temperature reaches 200 ° C. or more,
The plastic materials that can be surface-treated by this method are very limited and have a narrow scope of application. Needless to say, at a temperature higher than 100 ° C., most thermoplastic synthetic resins are softened or melted, so that it is not possible to achieve both high plastic workability and the advantages of ion plating.

[0007] What can be performed at lower temperatures is ion plating with sputtering. The present inventors have studied to form a film of a metal compound such as TiN by performing ion plating with sputtering on the surface treatment of plastic, but at first, the surface treatment had a beautiful appearance. Could not get the product. The film formed by ion plating is formed faithfully in the surface shape of the base plastic molded article, and its thickness is as thin as 0.05 to 1 μm, so that the base shape appears as it is. This can be improved by smoothing the inner surface of a mold for molding plastic and applying chrome plating or the like. However, this increases the cost, and as described above, chrome plating is a process that should be avoided as much as possible.

[0008] In order to solve the above-mentioned problem by increasing the thickness of the film formed by ion plating, it has been unsuccessful. Since a metal compound such as TiN is a ceramic, its coating is poor in flexibility, and its hardness is too different from that of the underlying plastic, so that it is easily peeled off or cracked from the surface of the plastic molded product. It is. Furthermore, a new problem has been encountered in that a plasticizer or a release agent added to the plastic is vaporized during the treatment under vacuum and may hinder formation of a desired metal compound.

As a countermeasure, the present inventors apply a cured resin coating on the surface of a plastic molded product, cure it, form a hard coat layer, measure the level of the rough plastic molded product surface, An attempt was made to harmonize the relatively soft plastic with the hard ion plating coating, and also to contain the plasticizer and mold release agent vaporized from the plastic. This attempt was successful to some extent, and prevented the peeling and cracking of the ion-plated coating and the adverse effects of additives, but the surface-treated product was unsatisfactory in terms of aesthetics. The expected bright colors could not be produced, and only dull colors could be obtained.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to improve the technique of coating the surface of a plastic molded article by ion plating, and to provide a product having a high surface hardness and a beautiful appearance. And a method of manufacturing the same.

[0011]

Means for Solving the Problems As shown schematically in FIG. 1, a plastic molded product subjected to the surface treatment of the present invention has a hard coat layer (3) and a hard coat layer (3) on a plastic molded product (1). A metal vapor-deposited film layer (4) and a metal or metal compound layer (5) formed by ion plating with sputtering are sequentially provided.

Between the plastic molded article (1) and the hard coat layer (3), there may be provided a primer layer (2) made of a material for promoting adhesion between the two.

According to the method of the present invention for producing a plastic molded article having been subjected to the above-mentioned surface treatment, a hard coat layer is formed on the surface of the plastic molded article, and a metal is vapor-deposited thereon to form a vapor-deposited film. And providing a metal or metal compound layer by ion plating.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION As a plastic for forming a molded article to which the surface treatment of the present invention is applied, a plastic having a low heat resistance temperature
It is unsuitable because the molded article may be deformed during processing. As long as this point is taken into consideration, any one can be selected, but suitable plastics include thermoplastic resins such as various polyolefins, polystyrenes, ABS resins, acrylic resins, polycarbonates and polyamides. If desired, cured resins such as urethane resins, epoxy resins, silicone resins can also be used. There is no limitation on the molding technique, and injection molding and extrusion molding are optional.

The material constituting the hard coat layer is determined mainly in consideration of the affinity of the substrate with the plastic. Examples of suitable ones for the present invention include urethane resins, silicone resins and acrylic resins which are cured by heating, air drying or ultraviolet rays. The use of the above-mentioned primer layer is preferable from the viewpoint of helping the adhesion between the substrate and the hard coat layer.

As for hard coats and primers, various hard coat agents and primers have been developed and used for the purpose of enhancing the abrasion resistance of the surface of plastic molded articles. Just choose. For example, Japanese Patent Application Laid-Open No. Hei 7-133441
No. proposes to use a primer mainly composed of an olefin-based oligomer as a primer suitable for a plastic lens, apply a silicone-based hard coat agent on the primer, and cure by heating.

As the hard coat layer, two or more multilayers may be optionally laminated. For example,
If you want to form a particularly durable surface, make the outer hard coat hard and the inner hard coat that supports it is relatively soft, and select and combine materials that are well compatible with the base plastic. is there. The thickness of the hard coat layer (in the case of multiple layers, the total thickness)
At least 1 μm is required, and preferably 3 μm or more. Usually, a thickness exceeding 100 μm is unnecessary, but depending on the surface condition of the plastic molded article, it may be advantageous to obtain a smooth surface with a thick hard coat layer.

When a metal or metal compound film is formed by ion plating, when a metal ion directly collides with the hard coat layer, the metal vaporized film layer penetrates into the hard coat layer due to its large energy. The composition of the plating film will be different from the composition of the metal or metal compound. In other words, the mixture of the metal or the metal compound and the plastic is considered to be the cause of the film becoming dull. Since the deposited film is a metal layer covering the entire surface of the base material,
It receives the impact of metal ions and allows its surface to be orderedly coated with a metal or metal compound.

One or more metals selected from Ti, Cr, Ta, Al, V and Zr are suitable as the metal constituting such a metal deposited film. Generally, on the premise of the above operation, the same metal component as the ion plating is preferable. If they are the same, high adhesion between the metal deposition film and the ion plating layer can be obtained. The thickness of the metallized film layer must be at least 0.01 μm, but need not exceed 1 μm.

The kind of metal or metal compound constituting the ion plating layer according to the present invention should be selected depending on the surface physical properties desired for the surface-treated product, and on the other hand, depending on the color. Preferred examples are TiN (gold), TiC (black), and (TiAl) -N (brown), each exhibiting the colors described in parentheses. The thickness of the layer is required to be at least 0.1 μm in order to ensure the improvement of the surface properties, but a thickness up to 5 μm is generally sufficient.

Of the various steps constituting the method for producing a surface-treated plastic molded article of the present invention, the preparation of the plastic molded article and the formation of the hard coat layer are performed in the field of plastic processing (including the use of a primer). Further, the subsequent formation of the metal deposition film and the formation of the coating film by ion plating can be performed using existing equipment according to a known technique in the field of vacuum surface treatment.

As an apparatus used for ion plating, an ion plating apparatus which can operate at a low temperature of 100 ° C. or less and utilizes sputtering is advantageous without being limited by a target plastic. However, even in other ion plating apparatuses (e.g., a method of giving energy to an evaporating substance such as Ti or Cr and evaporating the same, for example, an arc discharge, an ion gun, or a hollow cathode type), the evaporating substance and the ion plating are used. Any device that can be processed at a low temperature at a distance from the receiving object can be used in the practice of the present invention.

[0023]

EXAMPLE An emblem-shaped molded product to be attached to a front grill of a passenger car was manufactured by injection molding of an ABS resin. This was immersed in a polyurethane resin coating solution (manufactured by NRC) prepared as a primer agent, pulled up, drained by natural flow, air-dried at room temperature, and cured by heating to 50 ° C. for 60 minutes. . The film thickness is 0.
It was 5 μm. Subsequently, an ultraviolet-curable silicone resin paint (manufactured by Nippon RC Co., Ltd.) prepared as a hard coat agent was applied so as to have a film thickness of 10 μm, and was dried and cured by ultraviolet irradiation.

On the surface of the hard coat molded product thus obtained, an evaporated film of Ti having a thickness of 0.1 μm was formed by sputtering. Subsequently, ion plating was performed under the following conditions, and a TiN film having a thickness of 0.5 μm was provided.

Reaction gas: nitrogen Target (evaporation source): Ti Furnace temperature: 80 ° C. Processing time: 60 minutes A glossy gold-colored emblem with a luxurious appearance was obtained. Examination of the pencil hardness, which is generally used as an index of the surface hardness of the product, revealed that the chrome-plated product was H, whereas the product of the present invention had a value of 2H. This is because the surface hardness of the hard chrome plating is Hv600-800.
Whereas that of the TiN film is at least Hv10
This is consistent with the fact that it exceeds 00. When the ball was dropped separately and checked for its robustness against small impacts, the emblem was sufficiently practical.

[0026]

According to the present invention, even if an attempt is made to increase the smoothness of the surface of a plastic molded article by improving the smoothness, for example, even if the molded article is manufactured without chromium plating of the mold, the layers of the hard coat and metal deposition are laminated. By performing ion plating on the surface and forming a film of a metal or metal compound, it has sufficient surface hardness and a glossy or matte surface with beautiful colors inherent to the metal or metal compound of the film. A molded surface treated plastic molded product is obtained.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a layer structure on the surface of a plastic molded product subjected to a surface treatment of the present invention.

[Explanation of symbols]

Reference Signs List 1 plastic molded product 2 primer layer 3 hard coat layer 4 metal deposition layer 5 layer of metal or metal compound by ion plating

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C23C 14/06 C23C 14/06 Q 14/20 14/20 A // C08L 101: 00 C08L 101: 00 F term (reference ) 4D075 AE03 BB85Y CA02 CB02 CB04 DB31 DC38 EB22 EB38 EB43 4F006 AA12 AA15 AA22 AA34 AA36 AA37 AA38 AA42 AB24 AB37 AB39 AB73 BA02 BA14 DA01 DA04 4K029 AA11 BA01 BA03 BA07 BA58 BA58 BA02

Claims (7)

[Claims] 1. A plastic molded article which has been subjected to a surface treatment in which a hard coat layer, a metal deposited film layer, and a metal or metal compound layer formed by ion plating are sequentially provided on the plastic molded article. 2. The plastic molding according to claim 1, wherein the plastic is a thermoplastic resin selected from polyolefin, polystyrene, ABS resin, acrylic resin, polycarbonate and polyamide, or a cured resin selected from urethane resin, epoxy resin and silicone resin. Goods. 3. The material constituting the hard coat layer is selected from urethane resin, silicone resin and acrylic resin which are cured by heating, air drying or ultraviolet rays, and the thickness of the layer is 1 to 100 μm. Plastic molded products. 4. The method according to claim 1, wherein the metal constituting the metal deposition film layer is Ti,
One or more selected from Cr, Ta, Al, V and Zr, with a layer thickness of 0.01 to 1 μm
The plastic molded article according to claim 1, wherein 5. The metal or metal compound constituting the ion plating layer is one or more metals selected from Ti, Cr, Ta, Al, V and Zr or a nitride, carbide or nitrided carbide thereof. The plastic molded article according to claim 1, wherein the thickness of the layer is 0.05 to 5 µm. 6. The plastic molded article according to claim 1, further comprising a primer layer made of a material that helps the plastic and the hard coat layer adhere to each other on the plastic molded article. 7. A method of forming a hard coat layer on the surface of a plastic molded article, depositing a metal thereon to form a deposited film, and then providing a metal or metal compound layer by ion plating. A method of manufacturing plastic molded products with surface treatment.