JPH04338529A - Manufacture of synthetic resin composite molded item - Google Patents

Abstract

PURPOSE:To improve adhesive strength of a metal layer by a method wherein the surface of a molded item made of a thermoplastic resin which can be electrolessly plated is roughened and is press-fixed in a mold and a molded item made of a thermoplastic resin which is hardly electrolessly plated is filled to perform a composite molding and the roughened surface electrolessly plated. CONSTITUTION:A primary molded item 11 having projecting parts 2a and recessed parts 2b is injection-molded by using a polyether sulfone contg. palladium for a catalyst for electroless plating and a glass fiber. Then, the outer surface thereof is etched to roughen the exposed part 2c. Then, this primary molded item 11 is put into a mold 12 and the roughened face is brought into contact under pressure with the inner face of the mold 12. Then, a polyphenylene sulfide contg. a glass fiber and being hardly plated by means of electroless plating is cast into the mold 12 to mold a composite molded item 1. Electroless plating of the secondary molded item 13 thus obtd. is performed by means of the usual method to form a metal layer 4 on the exposed part 2c of the primary molded item 11.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a synthetic resin composite molded article, and more particularly to a method of manufacturing a synthetic resin composite molded article having a patterned metal layer firmly adhered to its surface.

0002

2. Description of the Related Art Plastic molded products, such as MCB (molded circuit bore), have a patterned metal layer on the surface that is used as an electric circuit pattern.
d) , MWB (molded wiring boa)
rd), MID (molded interconnection)
ction devices) are attracting attention as they meet various demands such as weight reduction, space saving, and cost reduction.

Conventionally, as a method for producing a plastic molded product having a patterned metal layer on the surface, electroless plating is used, as described in, for example, Japanese Patent Application Laid-Open Nos. 63-50482 and 1-207989. After forming the primary molded part of the part corresponding to the skeleton using a plastic material that is easy to plate (hereinafter referred to as "easy-plating material"), it is difficult to electrolessly plate the parts of the outer surface of the primary molded part that do not require plating. A widely used method is to inject a plastic material that is difficult to plate (hereinafter referred to as a difficult-to-plating material), and then secondary-forming the materials as one piece, and then forming a metal layer on the exposed portion of the easily plateable material by electroless plating. ing.

For example, first, as shown in FIG. 2A, a primary molded body 21 having a convex portion 21a having a flat top and a concave portion 21b therebetween is prepared using a primary molded material 22 that is easy to plate.
to form. Next, as shown in FIG. 2(B), in the mold 12 for secondary molding, a secondary molding material that is difficult to plate is placed in a cavity 12b in the mold, including the recess 21b of the primary molded body 21. By injecting 23, a secondary molded product 24 having a cross section as shown in FIG. 2(C) is formed. In the secondary molded product 24, the above-mentioned recess 21b is filled with a secondary molding material 23 that is difficult to plate. When the upper surface 24a of the secondary molded product 24 removed from the mold is roughened as shown in FIG. 2(D) and then subjected to electroless plating, the primary molded product is formed as shown in FIG. 2(E). The metal layer 25 is formed only on the surface of the portion 21c where the easily plateable primary molding material 22 is exposed on the surface of the secondary molded product 24, which corresponds to the convex portion 21a of the second molded product 21. In this way, a synthetic resin composite molded product (plastic two-shot substrate) 26 having a metal pattern is obtained.

Easily plateable materials include plastic materials that are amorphous or have a relatively low molecular weight and are easily roughened physically or chemically, or plastics that have added catalysts containing noble metals such as palladium, gold, and silver. material is used. In the former case, that is, when using a plastic material that is easily roughened and does not contain a catalyst, a process is performed in which a catalyst containing a noble metal is applied to the surface in advance before electroless plating is applied.

[0006]

[Problems to be Solved by the Invention] However, the above conventional methods have the following disadvantages. That is, the adhesive strength of a metal layer formed by electroless plating to a plastic material is determined according to JIS. C5012
According to the test, it was about 1.0 kgf/cm, and it peeled off relatively easily. Not only that, when the surface is roughened, the chemical solution penetrates the interface between the easily plated material and the difficult to plate material, and after plating, it gradually oozes out, causing the plating film to deteriorate.
This may result in poor insulation of electrical circuits.

The object of the present invention is to provide a synthetic resin composite having a patterned metal layer on the surface, which has a high adhesive strength and is improved so that the metal layer does not deteriorate due to seepage of a chemical solution for surface roughening. The goal lies in the realization of a method for manufacturing molded products.

[0008] In the present invention, the adhesive strength of the metal layer is high;
In order to realize a method for manufacturing a synthetic resin composite molded product with a patterned metal layer on the surface, which is improved so that the metal layer does not deteriorate due to oozing of chemicals for surface roughening, we developed an easily plated material (the surface is of a first molded body made of a first thermoplastic resin (a first thermoplastic resin whose surface can be roughened and subjected to electroless plating);
At least a predetermined portion of the surface is roughened, it is fixed in a mold, a predetermined portion of the first molded body is pressed, and a difficult-to-plating material (a material that is difficult to electroless plate,
A composite molded article was formed by filling the composite molded article with a second thermoplastic resin, and electroless plating was applied to the surface of the composite molded article on the pressed first molded article. Pressing a predetermined portion of the first molded body can be easily performed by pressing the inner surface of the mold against the surface of the first molded body during mold clamping before secondary molding.

[0009] The first thermoplastic resin is required to have rigidity, dimensional stability, and heat resistance because the primary molded product forms the skeleton of the composite molded product and also functions as a core during secondary molding.
Since electrical properties must also be considered, the material is usually selected from among so-called engineering plastics. For example, polycarbonate, polyamide, polyetherimide, polysulfone, polyethersulfone, polyaryl sulfone, polyphenylene sulfide, polyarylate, polyethylene terephthalate, polybutylene terephthalate, polyetherketone, polyetheretherketone are preferred. Liquid crystal polymers, such as Novaculate (trade name), Vectra (trade name), or phenolic resins,
Thermosetting resins such as epoxy resins and diallyl phthalate resins may also be used. Fillers such as glass fiber, potassium titanate fiber, and calcium carbonate may be added to these resins.

The second thermoplastic resin can be selected from these materials in the same way as the first thermoplastic resin, but it is preferable that the molding temperature is lower than that of the first thermoplastic resin.

[0011] Since it is necessary to form a patterned metal layer on the surface of the primary molding, the easily plated material (first thermoplastic resin) used as the primary molding material is amorphous or relatively low molecular weight and coarse. It is preferable to use materials that are easily surfaced or easily attacked by specific solvents, chemicals, etc. Also, palladium,
It is advantageous to use a catalyst to which a noble metal catalyst such as gold or silver is added because it eliminates the need for a step of applying a catalyst to the primary molded body before electroless plating.

[0012] Electroless plating is used to form a metal layer on the exposed portion of the primary molded body on the surface of the composite molded body. Electroless plating is performed on a roughened and pressed surface portion of a primary molded body made of an easily plated material. Before performing electroless plating, if necessary, a pretreatment of imparting a noble metal catalyst such as palladium, gold, or silver may be performed.

[0013] In order to roughen the surface of a primary molded body made of an easily plated material, it is usually first treated with an alkaline cleaner,
Removes dirt such as mold release agents, fat, and dirt adhering to molded products using surfactants, organic solvents, etc. Next, after processing with N,N-dimethylformamide, etc. as necessary, the surface is roughened using an etching solution such as chromic acid/sulfuric acid, calcium hydroxide, hydrofluoric acid/nitric acid, acidic ammonium fluoride/nitric acid, etc. do. Such surface roughening treatment makes it possible to obtain sufficient adhesive strength between the plated layer and the plated layer.

[0014] It is preferable to use a primary molding material which has been made easier to plate by adding a plating catalyst in advance, in order to selectively form a metal layer on the outer surface of the primary molding material. The electroless plating catalyst to be added in advance to the primary molding material may include simple substances and compounds of metals of Group VIII and Group IB of the periodic table, such as copper, silver, gold, nickel, platinum, palladium, rhodium, iridium, and the like. salt,
Oxides etc. can be used. It is also possible to selectively form a metal layer on the outer surface of the primary molding material by roughening and pressing only the primary molding material.

Instead of adding a catalyst for electroless plating to the primary molding material in advance, a step of applying a catalyst may be added after surface roughening. The method for applying the catalyst is the catalyst-accelerator method, in which the material is immersed in a mixed catalyst solution containing metals such as palladium and tin, and then activated with an acid such as hydrochloric acid or oxalic acid to roughen the surface of the secondary forming material. A method of precipitating palladium etc. on the surface and a sensitizing-activating method, that is, a strong reducing agent such as stannous chloride, hydrazine chloride, hypophosphorous acid, etc., is applied to the required parts of the roughened and easily plated material. After adsorption, there is a method in which the precious metal is precipitated by immersion in a catalyst solution containing noble metal ions such as palladium and gold. The step of applying the catalyst may be performed either before or after the secondary molding, but preferably after the secondary molding.

After the pretreatment, plating with copper, nickel, etc. is applied using an electroless plating (chemical plating) method. In some cases, copper is electrolessly plated with nickel and then gold. When a metal layer is used as a wiring part of an electric circuit pattern, generally a copper layer or a layer of nickel, gold, solder, etc., alone or in combination, is formed on the copper layer. On the electroless plated layer, a layer of the same or different metal may be further formed by ordinary electroplating using this layer as a conductor (for example, an electroplated nickel layer on an electroless plated copper layer). This method is useful when sufficient thickness of the metal layer cannot be obtained by electroless plating.

[0017]

[Effect] The surface of the composite molded product where the primary molded body made of easily plated material is exposed has been roughened and pressed in advance, so the metal layer can be selectively removed by electroless plating. The metal layer adheres to the primary molded body more firmly than when the surface is roughened but not pressed. As a result, a patterned metal layer that does not peel off easily is formed on the surface of the composite molded product. Since the surface roughening is performed before secondary molding, unlike when the surface is roughened after secondary molding, the chemical solution used for surface roughening does not seep into the interface between the primary molded body and the secondary molded body. Therefore, the surface of the metal layer formed on the outer surface of the secondary molded body and the vicinity thereof will not be contaminated by the chemical solution seeping from the interface between the primary molded body and the secondary molded body.

[0018]

[Examples] The present invention will be explained in more detail with reference to Examples below. [Example 1] An example of a synthetic resin composite molded product having a metal pattern manufactured according to the present invention is shown in FIG. 1(F). In the synthetic resin composite molded product 1, the concave portions 2b between the convex portions 2a of the primary molding material 2 are filled with the secondary molding material 3, and a metal layer is formed on the surface of the exposed portions of the convex portions 2a of the primary molding material 2. 4 was formed. The primary molding material 2 was polyether sulfone (p
secondary molding material 3
is polyphenylene sulfide containing 30% by weight of glass fiber as a filler.
ide).

This plastic composite molded article 1 is manufactured by the following method. Using polyether sulfone containing a palladium catalyst and glass fiber as the primary molding material 2, a primary molded body 11 having a cross section shown in FIG. 1(A) is injection molded by a conventional method. The injection molding temperature was 380°C, and the mold temperature was 150°C. A convex portion 2a and a concave portion 2b are formed in the primary molded body 11.

Next, the outer surface of the primary molded body 11 is degreased by a conventional method, dipped in N,N-dimethylformamide for 2 minutes, and then etched by immersed in a chromic acid/sulfuric acid etching solution at a temperature of 60° C. for 4 minutes. As shown in FIG. 1(B), the exposed portion 2c of the primary molding material was roughened. After washing with water, as shown in FIG. 1(C), the primary formed body 11 is placed in the mold 1
2 and clamps the mold 12, the roughened surface of the top of the convex portion 2a of the primary molded body 11 is pressed against the inner surface 12a of the mold 12, and the degree of roughness is reduced. do.

Polyphenylene sulfide to which glass fiber has been added is injected as the secondary molding material 3 through a gate (not shown), and the secondary molding material is poured into the cavity 12b including the recess 2b of the primary molded body 11, as shown in FIG. 1(D). Fill with molding material 3. As a result, a secondary molded product 13 shown in FIG. , A composite molded product that is composed of a primary molded product and a secondary molded product and does not have a metal layer is called a secondary molded product). The injection molding temperature was 300°C and the mold temperature was 100°C. The secondary molded product 13 is obtained by roughening and pressing the primary molded product 11.
It has an exposed portion 2c.

[0022] The surface of the secondary molded product 13 is again degreased,
After washing with water, electroless copper plating was performed by a conventional method to deposit copper as a metal layer 4 to a thickness of 30 microns on the exposed portion 2c of the primary molded body. In this way, a synthetic resin composite molded article 1 having a cross section shown in FIG. 1(F) is obtained.

The adhesive strength of the metal layer 4 formed by electroless plating to the primary molded body 11 is determined according to JIS. C50
12, it was approximately 1.8 kgf/cm. Furthermore, no stains on the surface of the metal layer 4 were observed even after being left at room temperature for 30 days.

[Example 2] A synthetic resin composite molded article was produced in the same manner as in Example 1, except that polyether sulfone was used instead of polyphenylene sulfide. The adhesive strength of the metal layer was approximately 1.8 kgf/cm (JIS
．． C5012). Further, no stains on the surface of the metal layer were observed even after being left at room temperature for 30 days.

[Comparative Example 1] For comparison, a composite molded article was manufactured by a conventional method. That is, the primary molded product was inserted into a mold without surface roughening, secondary molding was performed, and then the surface of the secondary molded product was roughened and electroless plating was performed.

Specifically, using the same primary molding material 22 as in Example 1, the primary molded body 21 shown in FIG. 2A is injection molded, and this is inserted into the mold 12. As shown in (B), the same secondary molding material 2 as in Example 1 is placed in the cavity.
3 (secondary molding) to obtain a second molded product 24 as shown in FIG. 2(C). Thereafter, the outer surface of the secondary molded product 24 was degreased in the same manner as in Example 1, immersed in N,N-dimethylformamide for 2 minutes, and then chromic acid/
Etch by immersing in sulfuric acid etching solution for 4 minutes,
As shown in FIG. 2(D), the upper surface 24a of the secondary molded product 24
The surface was roughened. After washing with water, copper was deposited as a metal layer 25 to a thickness of 30 microns on the exposed portion 21c of the primary molded body by electroless copper plating similar to that in Example 1, as shown in FIG. 2(E). In this way, a synthetic resin composite molded article 26 having a cross section shown in FIG. 2(E) was manufactured.

[0027] The adhesive strength of the metal layer is approximately 1.0 kgf/cm.
(according to JIS.C5012). Further, after being left at room temperature for 2 days, stains were observed on the surface of the metal layer.

[Comparative Example 2] A synthetic resin composite molded article was produced in the same manner as in Comparative Example 1, except that polyether sulfone was used instead of polyphenylene sulfide. Similar to Comparative Example 1, the adhesive strength of the metal layer is approximately 1.0 kgf/cm
(according to JIS.C5012). Further, after being left at room temperature for 2 days, stains were observed on the surface of the metal layer.

[0029]

[Effect of the invention] The synthetic resin composite molded product produced by the method of the present invention has a high adhesive strength of the metal layer formed in a pattern on the surface, and can be used in the surface roughening process before electroless plating. The metal layer does not deteriorate due to seepage of the chemical solution onto the surface.

[Brief explanation of drawings]

FIGS. 1A to 1F are explanatory cross-sectional views showing one embodiment of the method for manufacturing a synthetic resin composite molded article according to the present invention.

FIGS. 2A to 2E are explanatory cross-sectional views showing a conventional method for manufacturing a synthetic resin composite molded product.

[Explanation of symbols]

1 Synthetic resin composite molded product 2a Primary molding material or convex portion 2b of the primary molded product
Recessed portion 2c of primary molding material or primary molded body Exposed portion of primary molding material 3 Secondary molding material 4 Metal layer 11 Primary molded body 12 Mold 12a Inner surface 12b of mold Cavity 13 Secondary molded product 21 Primary molded body 21a Primary molding Convex portion 21b of the body Concave portion 21c of the primary molded product Surface 22 where the primary molded product is exposed
Primary molding material 23 Secondary molding material 24 Secondary molded product 24a Upper surface 25 of secondary molded product Metal layer 26 Synthetic resin composite molded product

Claims (3)

[Claims] 1. A first molded article made of a first thermoplastic resin whose surface can be roughened and subjected to electroless plating. A first molded body is fixed in a mold, the predetermined portion of the first molded body is pressed, and the cavity in the mold is
Filled with a second thermoplastic resin that is difficult to electroless plate,
A synthetic resin composite comprising forming a composite molded article, and applying electroless plating to the surface of the composite molded article on the pressure-welded portion of the first molded body to form a patterned metal layer. Method of manufacturing molded products. 2. The method for manufacturing a synthetic resin composite molded article according to claim 1, wherein the pressing is performed by pressing the inner surface of the mold against the predetermined portion of the first molded body. 3. The synthetic resin according to claim 1, wherein the surface roughening is performed by a chemical roughening method using a chemical solution, and the chemical solution is removed by washing before fixing in the mold. Method for manufacturing composite molded products.