JPH0457756B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a novel treatment method for applying plating treatment to the surface of a composite material molded product provided with a synthetic resin or a reinforcing material using a synthetic resin as a matrix. .

[Background technology]

When metal plating is applied to the surface of molded products made from ABS, nylon resin, etc., the polarity is easily maintained through etching treatment, and the resin surface is roughened, that is, dented in order to maintain an anchor effect. It is possible to form

However, in the case of resins for which surface roughening is impossible or extremely difficult, such as polycarbonate and epoxy resins, and composite materials made of these materials as a matrix with reinforcing materials, metal plating cannot be applied. Even when plating is applied by this method, the peel strength of the resulting film is extremely low, making it impractical.

In order to improve the above-mentioned problems, the present inventors first proposed a method that enables strong metal surface treatment to be applied to resin molded articles (Japanese Patent Application Nos. 132844 and 184808, 1982).

That is, metal powder is blended with a synthetic resin that has a suitable adhesive property on the surface of a resin molded product, and then applied to the surface of the molded product and cured to make it conductive, and then electroless or direct electrolytic plating is applied. This results in a strong metal surface treatment.
By this method, it is possible to easily perform electroless plating and electrolytic plating, especially on epoxy-based and composite material molded products, which has heretofore been considered impossible.

[Purpose of the invention]

The present invention aims to further improve the adhesion between the base resin layer and the plated metal layer by improving the conductivity imparting process during the above treatment process.

[Structure of the invention]

A mixture of a dendritic metal powder having protrusions on the surface and a synthetic resin having adhesive properties is applied to the surface of a synthetic resin or a composite material molded product having a synthetic resin matrix in such a manner as to maintain electrical conductivity. The method is to apply electroless or direct electrolytic plating treatment to a molded article with a part of the metal powder exposed after curing.

The metal powder of the present invention has conductivity even when mixed with a synthetic resin that has adhesive properties, and is a powder of silver, copper, nickel, etc., and the important point is the shape of the powder. be. In other words, it is not plate-shaped,
Moreover, it is not necessary to have a linear shape, but to exhibit a so-called dendritic shape.

Here, dendritic means (a) tree trunk 1, as shown in Figure 1.
Those having at least a protrusion 2 such as a branch bud, (b)
(c) Those with branch-like protrusions 3 that have grown to a certain extent, and (c) those with sufficiently grown branch-like protrusions 4. These are called dendritic metal powders A.

Such dendritic metal powders having protrusions on the surface preferably have a particle size of 1 to 10 μm (maximum length), and these powders are capable of directly depositing metal in powder form on the cathode by metal electrolysis. It is produced by the electrolytic method obtained by the electrolysis method, or by the carbonyl method, in which gaseous nickel tetracarbonyl is produced by passing carbon monoxide gas through crude nickel metal at a temperature of 40 to 90°C, and nickel is obtained as a fine powder by thermal decomposition of this carbonyl gas. It is something that will be done.

Hereinafter, a method for obtaining electrical conductivity by surface-treating a synthetic resin or composite material molded article with a dendritic metal powder having protrusions on its surface will be explained with reference to FIG. 2 and subsequent figures. Figure 2 shows a state in which dendritic metal powder A is dispersed on the surface of a part 5 of a synthetic resin molded product. If the powders are not in contact with each other, the conductivity of the dispersed layer as a whole cannot be obtained. Therefore, in these dendritic metal powders A, as shown in FIG. 3, the synthetic resin 6 serving as an adhesive is buried in the gaps between the powders, and a portion of the powders are covered at an appropriate ratio on the outermost surface of this system. Must be exposed. In addition, the synthetic resin 6 buried in the powder gap acts as a strong adhesive, so that the blended layer with the powder is firmly bonded to the synthetic resin base 5.

The system subjected to such treatment consists of a mixture of dendritic metal powder group A and synthetic resin 6 as an adhesive, as shown in FIG. Therefore, not only does the entire system maintain conductivity, but also there are recesses formed everywhere due to the arrangement of powder group A, and when these recesses are plated with metal, the plating becomes difficult. The layer fills the depression and exerts an anchor effect.

As is clear from FIG. 4, the plating layer 7 is precipitated and deposited in the recesses 8 and 8' formed by the blending system of the powder A group and the synthetic resin 6 as an adhesive.

Thus, as shown in FIG. 5, a metal plating layer 7 is formed on the surface of the compound of the dendritic metal powder A and the synthetic resin 6 as an adhesive on the base 5, and the adhesion of the plating layer is extremely strong. Become. In this way, we are now able to perform not only electroless plating with strong adhesion on the surfaces of polycarbonate, epoxy, etc., and composite material moldings that use them as a matrix, but also direct electrolytic plating, which has been considered impossible or difficult in the past. It becomes possible to apply

As for the type of metal, silver provides the most stable and high conductivity, but sufficient plating can be achieved with copper or nickel in combination with an adhesive.

The composite material used in the present invention is preferably made of fibers of wholly aromatic polyamide, carbon fiber, glass fiber, or silicon carbide.

Hereinafter, the present invention will be specifically explained with reference to Examples.

Example 1 A dendritic silver powder having protrusions on the surface obtained by electrolysis with a maximum length of about 3.5 μm and an epoxy thermosetting resin (flowing and viscous at room temperature) were mixed in a weight ratio of 7:
After mixing and stirring thoroughly, the mixture was coated on the surface of a molded plate made of epoxy synthetic resin to a thickness of about 25 μm. After such treatment, 130℃
The coating film was cured by drying for 120 minutes.
The volume resistivity of the surface of the treated plate thus obtained was measured to be 3×10 ^-3 Ωcm, and this plate was then electrolytically plated with copper under the following conditions.

Copper sulfate 250g/l Sulfuric acid 30g/l Temperature 35°C Current density 0.9Am/dm ² Treatment time 30 minutes The copper plating layer obtained by the above treatment has a thickness of approximately 30μm, and the peel strength of this plating layer As a result of the measurement, it was 3.3Kg/cm.

On the other hand, using nearly spherical silver particles with an average diameter of about 3 μm, the same treatment as above was performed and copper plating was performed, and the resulting copper film had a peel strength of 1.3 Kg/cm.

Example 2 A dendritic nickel powder (maximum length 2.5 μm) having protrusions on the surface obtained by the carbonyl method was mixed with an epoxy curable resin at a weight ratio of 7.5:2.5. After coating to a thickness of approximately 30 μm on a molded plate made of epoxy resin, the coating was cured by drying. Next, this treated plate was subjected to electroless plating under the following conditions.

Copper sulfate 20g/l Lotsiel's salt 60g/l Potassium carbonate 30g/l pH 30g/l A solution Formalin (37% solution) 30c.c. B solution After thoroughly mixing A and B solutions, at 85℃ for 60 minutes, As a result of immersion treatment of the above plate, a 1.5 μm copper film was obtained. Thereafter, electrolytic copper plating was carried out under the same conditions as in Example 1, and a 38 μm thick copper film was obtained, with a peel strength of 2.9 Kg/cm. still,
When flaky nickel (average diameter 4 μm) was treated in the same manner as above, the peel strength was 1.4 kg/cm.

As is clear from Examples 1 and 2, the effects of forming a plating layer on electroless or electrolytic plating on a conductive surface treated product obtained using the dendritic metal powder having protrusions on the surface according to the present invention It can be seen that the adhesion is far superior to that of metal powder pairs of other shapes.

[Brief explanation of the drawing]

FIG. 1 shows an example of the shape of a dendritic metal powder having protrusions on the surface used to maintain conductivity according to the present invention, and FIG. FIG. 3 shows a state in which the particles A are dispersed and arranged, and FIG.
The system shown in the figure shows a state in which the electroplated layer 7 is coated on the surface, and FIG. 5 shows a state in which plating has been completed.

[Claims]

1. In the method of fully immersing a gravure printing cylinder in an acidic copper sulfate bath and applying copper plating to its surface while rotating it, it is possible to use a non-current-carrying material such as rubber or resin that has holes of various sizes drilled in it. By attaching shielding plates of the type near both ends of the gravure printing cylinder, the amount of current applied to both ends of the gravure printing cylinder can be freely adjusted while covering the entire surface of the gravure printing cylinder. A copper plating method for gravure printing cylinders characterized by applying copper plating.