JPH036225B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic substrate whose surface is modified by grafting a radically polymerizable compound in contact with the plastic substrate by irradiating it with actinic rays such as ultraviolet rays or electron beams. This relates to a method for electroless plating on materials.

The present invention aims to improve the efficiency and physical and chemical performance of electroless plating by simplifying electroless plating. Conventional electroless plating on polymeric compounds such as plastics involves degreasing, etching (soaking in a chromic acid mixture), rinsing (thoroughly),
Neutralization, washing with water, sensitization, washing with water, activation,
The problem was that it required a long process of washing with water, chemical plating, and washing with water, and the conditions were complex and difficult to control. In particular, in the process, etching is applied to match the object to be plated.
The purpose is to activate the surface of the object to be plated so that it has a chemical bonding force, increase the adhesion force with the unevenness and shape of the surface, and further improve the water wettability of the object to be plated during plating. . However, in the case of plastic plating, this etching becomes rate-limiting and makes the base uneven, making the roughness of the plating film noticeable. In general, plastics have poor hydrophilicity, and when metal ions precipitate to form a metal film, it is difficult to obtain adhesion to the metal film. As an etching agent, this solution is treated at a high temperature of about 70 to 95℃,
By roughening the surface, the adhesive strength is increased. Even when relatively harsh etching conditions are not required, it takes several minutes or more and the etching process becomes long. If the conditions are made stricter in order to shorten the time, the surface roughness will increase and the applications will be limited.

As a result of various studies to solve the above-mentioned problems, the present inventor has made the following invention which is different from the conventional method. That is, the present invention relates to the production of α,β-ethylenically unsaturated carboxylic acid or α,β-ethylenically unsaturated carboxylic acid, which is brought into contact with a plastic substrate by irradiation with actinic rays such as ultraviolet rays or electron beams. This is a method in which electroless plating is performed on the surface of the base material, which has been surface-modified by grafting a radically polymerizable compound, which is a monomer mainly composed of esters.

Various surface treatment methods have been attempted to modify the surface of plastic substrates, such as corona discharge treatment, oxidation treatment, fire treatment, actinic radiation graft bonding, and film coating. Corona discharge treatment, oxidation treatment, and fire treatment methods have the disadvantage of impairing the chemical properties, mechanical properties, etc. of the substrate. Furthermore, the corona discharge treatment has the disadvantage that the treatment effect is not very reliable, and its uniformity and durability are poor. on the other hand,
In film application, not only is there a problem with adhesion to the polymeric substrate, but also the treated substrate has unique mechanical properties due to the two-layer structure in which the plastic substrate and the coating layer have different properties. It also has the disadvantage of considerably losing its chemical properties. Incidentally, actinic ray graft bonding itself has been known for a long time, but this method generally causes less loss of the properties of the treated base material and is therefore a good method.

Although the physical properties of the surface are partially changed by surface modification by graft bonding, the present invention is characterized in that the surface is smooth while maintaining the chemical and mechanical properties of the base material. Furthermore, electroless plating can be carried out efficiently without being rate-limiting like etching.

The plastic base material according to the present invention includes:
These include films, sheets, plates, and other molded products made of polyethylene, polypropylene, ethylene-propylene copolymer, polyester, polycarbonate, polyimide, epoxy resin, etc., and may also be base materials using two or more types of plastics. Furthermore, dimensionally stabilized substrates reinforced with gas fibers, carbon fibers, etc. may also be used. In the present invention, since active energy ray irradiation is performed to modify the inner surface, the shape of the base material is preferably a film, sheet, or plate. The plated tapes, sheets, disks, etc. obtained by the present invention are superior in terms of productivity and uniformity of quality.

The plastic base material according to the present invention is preferably a plastic that allows radically polymerizable compounds to be easily graft-bonded by actinic rays and is resistant to deterioration by irradiation with actinic rays.
If the material is easily deteriorated by electron beam irradiation, it is desirable to use ultraviolet irradiation.

The radically polymerizable compound used in the present invention is a monomer mainly composed of α,β-ethylenically unsaturated carboxylic acid or α,β-ethylenically unsaturated carboxylic acid ester, Examples of unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, and maleic anhydride. In addition, as α,β-ethylenically unsaturated carboxylic acid esters, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, dimethyl fumarate, monoethyl maleate, maleic acid dimethyl etc. As the radical polymerizable compound, other radical polymerizable compounds can be used in addition to α, β-ethylenically unsaturated carboxylic acid or α, β-ethylenically unsaturated carboxylic acid ester, but the amount thereof is 50
less than % by weight. From the viewpoint of adhesion to metals, carboxylic acids such as acrylic acid, methacrylic acid, and maleic anhydride are preferable.

In surface modification, known radical polymerization initiators are used as needed. For example, there are benzoin ethers, azobisisobutylnitrile, etc. that can be used alone, and benzophenone, acetophenone, etc. that can be used by abstracting active hydrogen from other molecules, but they are not necessarily used in the case of electron beams. In the case of ultraviolet rays, it is not necessary to use ultraviolet rays depending on the combination of the type of radically polymerizable substance and the type of base material.

Although it is possible to bring the radically polymerizable compound used in the present invention into contact with the substrate alone, it is preferable to use a solvent in order to apply it thinly to the surface of the substrate. The solvent is one that does not dissolve or deform the surface of the base material, and known solvents may be used alone or in combination. The concentration of the solution ranges from 0.01 to 100% by weight, preferably from 0.1 to 10% by weight. water,
Mixtures of water and organic solvents, water-soluble solvents, etc. are effective from the viewpoints of work safety, economy, and post-treatment. After surface treatment, it is necessary to remove unreacted substances, and when a water-soluble radically polymerizable compound or solvent is used, washing with water is possible, and such a compound can be selected.

In the present invention, any means such as coating can be used to bring the radically polymerizable compound into contact with the surface of the base material.
Known means such as a flow coater and spray can be used. In the case of coating, the thickness of the film to be contacted is 1 to 50μ
It is. It is desirable to provide a protective layer with a thickness of about 10 μm on this coating film, and the protective layer is preferably made of polypropylene, polyester, or the like. Covering with a protective layer has the advantage that volatilization and repelling of the radically polymerizable compound are eliminated. Electroless plating may also be possible for the protective layer.

To give an example of ultraviolet irradiation used in the present invention, when five 2KW ultraviolet lamps are used and the distance between the substrate surface and the lamps is 12 cm, the line speed is preferably 0.2 to 20 m/min. If it exceeds 20 m/min, sufficient modification will not be obtained, and if it is less than 0.2 m/min, the base material will deteriorate and lose its original properties. As an example of electron beam irradiation, an irradiation amount of 0.1 to 100 Mrad is suitable, but it is desirable to select the appropriate amount depending on the type of the base material. In the case of a polyester base material, 1 to 50 Mrad is good; if it is less than 1 Mrad, sufficient modification will not be obtained, and if it exceeds 50 Mrad, the line speed will slow down, eventually causing deterioration of the base material.

In addition, in some cases, X-rays,
It is also possible to use alpha rays, etc.

In the present invention, the base material is degreased and brought into contact with a radically polymerizable compound, further covered with a protective film, and irradiated with actinic rays such as ultraviolet rays or electron beams from the protective film or the base material side, sensitized,
The process consists of washing with water, activation, washing with water, chemical plating, and washing with water, and the rest is the same as the conventional method. Since this step does not involve etching, surface modification occurs while maintaining the surface smoothness and properties of the base material. The most important feature of the present invention is that it eliminates the etching operation and allows electroless chemical plating to be performed while retaining the properties of the base material and without generating surface irregularities. Furthermore, depending on the type of base material, it is also possible to omit the sensitization operation.

The plating film obtained by the present invention is uniform, has few pinholes, and has a strong adhesive force. Effective for magnetic tapes, magnetic sheets, magnetic disks, etc. It can also be made into a printed circuit by plating it with copper or the like and later etching it into the required pattern. It can also be made into a pattern and used as an optical mask for printing printed circuits. According to the present invention, only the surface-modified portion is plated, so it is extremely effective in cases where double-sided plating is harmful, and is extremely advantageous for magnetic recording bodies and printed circuits. On the other hand, with conventional etching methods, it is very difficult to pre-process only one side, so this is a significant advantage. A particularly good surface is that it does not undergo etching, so the plating film has no irregularities and has good gloss, which is extremely advantageous for magnetic recording materials that require smoothness. Since there is no residual strong acid or strong alkali that is used in the strong etching process for printed circuits, there is no decrease in board surface resistance and there are fewer problems with current leakage. Note that it is also possible to treat both sides of the base material in one treatment.

Further, after electroless plating has been performed on a plastic substrate according to the present invention, normal electrolytic plating can be performed.

Next, the present invention will be further explained with reference to Examples.

Example 1 A biaxially stretched polyethylene terephthalate film base material (thickness 70μ) was cut into 140 mm width and 140 mm length, and a 0.1 wt% acrylic acid solution in acetone was added to the base material.
Coat it to a thickness of 3μ, cover with a protective layer of polyethylene terephthalate film (thickness 15μ), and use it as a sample. Perform electron beam irradiation at 20 Mrad, remove the protective layer, and wash with water. This sample was treated with a sensitizing treatment solution called Pink Schumer (trade name, manufactured by Nippon Kanigen Co., Ltd.).
Sensitize for 2 minutes using After washing with water, activation is performed at 50° C. for 3 minutes using an activation treatment solution, Red Shumer (trade name, manufactured by Nippon Kanigen Co., Ltd.).
After washing with water, apply electroless chemical plating for 60 minutes using electroless nickel plating liquid (product name: Nippon Kanigen Co., Ltd.).
℃ for 1 minute, then rinse with water. After thoroughly air drying,
In order to investigate the mechanical properties of the mesh film,
The condition after rubbing was observed, and it was found to be in good condition.
Further, the adhesive property was tested by peeling off cellophane tape, but it did not peel off.

Comparative Example 1 Electron beam irradiation was performed and plating was performed without using the 0.1% by weight acetone solution of acrylic acid in Example 1, and the same operation was performed. The plating film was peeled off by rubbing it once with a cotton cloth, and the mechanical strength and adhesion of the film were poor.

Example 2 Polyimide film base material (product name KAPTON)
H type (manufactured by Toray Dupont Co., Ltd.) was cut into 140 mm width and 140 mm length, and a 0.1% by weight acetone solution of acrylic acid was applied to a thickness of 3μ, and a protective layer of polyethylene film (thickness 15μ) was placed on top. cover it with water and use it as a sample. Perform electron beam irradiation at 40 Mrad, remove the protective layer, and wash with water. Electroless chemical plating is carried out in the same manner as in Example 1. The results were similar to Example 1. Further, the film was treated in an oven at 330°C for 20 minutes, and although some shrinkage of the film was observed, no peeling from the plating film was observed. Also,
The results of JISC6481 soldering heat resistance (260°C, 60 seconds) were also good.

Example 3 When the same operation as in Example 2 was carried out using methacrylic acid instead of acrylic acid and the test was conducted, the same results were obtained and the results were good.

Example 4 The ultraviolet irradiation conditions were as follows: seven 2KW ultraviolet lamps were arranged in parallel in a direction perpendicular to the film movement direction, the film movement speed was 10 m/min, and the distance between the film and the ultraviolet lamp was 12 cm. 5μ thick on polypropylene film (70μ), 0.1% by weight
Apply an acetone solution of acrylic acid and cover with approximately 10μ polypropylene film. This sample is irradiated under the above conditions. After washing with water, the same operation as in Example 1 was carried out and the test showed good results in both mechanical properties and adhesive properties.

Example 5 A similar operation was carried out using a 0.05% by weight acrylic acid solution in place of the 0.1% by weight acrylic acid solution in Example 2, and the test was conducted. The results were the same as in Example 2, and the concentration was Almost no effect was observed.

Comparative Example 2 The same operation as in Practical Example 2 was performed without using the 0.1% by weight acrylic acid acetone solution, but with electron beam irradiation and plating. The results were poor in both mechanical strength and adhesiveness.

Example 6 Similar operations were performed using a polypropylene film base material (70μ) and electron beam irradiation of 20 Mrad in place of the polyethylene terephthalate film base material of Example 1, and the results showed that the mechanical strength,
Both adhesion properties were good.

Claims (1)

[Claims] 1 Polyethylene, polypropylene, ethylene-
Films, sheets, plates, and other molded products made of propylene copolymers, polyesters, polycarbonates, polyimides, epoxy resins, etc., base materials made of two or more types of plastics, or plastics reinforced with glass fibers, carbon fibers, etc. A 0.1 to 10% by weight solution of a radically polymerizable compound that is an α,β-ethylenically unsaturated carboxylic acid or α,β-ethylenically unsaturated carboxylic acid ester monomer is brought into contact with the substrate and covered with a protective layer. An electroless plating method, which comprises performing electroless plating on the base material whose surface has been modified by graft bonding by irradiation with actinic rays.