JPH0249387B2 - HORIESUTERUJUSHINOMUDENKAIMETSUKIHOHO - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for plating polyester resin, and more particularly to an etching method when performing electroless plating. BACKGROUND OF THE INVENTION 2. Description of the Related Art Electrolytic plating is known as one of the methods for plating synthetic resin molded articles. This method involves performing (a) a cleaning process, (b) an etching process, (c) a sensitization process, (d) an activation process, and (e) an electroless plating process on the object to be plated to form an electroless plating film. This is a method in which electrolytic plating is performed after forming and imparting conductivity. Generally, it is known that the etching process has the greatest effect on the adhesion between the plating film formed by this method and the resin. In ABS resin, which is mainly used as a plastic material for plating, butadiene is oxidized and dissolved during the etching process.
The holes created are used to obtain excellent adhesion between resin and metal. However, ANG resin has a drawback of poor heat resistance, so its uses are limited. On the other hand, polyester resin not only has excellent heat resistance, but also excellent mechanical, electrical properties, and chemical resistance, and in particular, polyester resins with various fillers added have even better properties. It is expected that it will be widely used as a so-called engineering plastic. Therefore, by plating the polyester resin with good adhesion, its uses will be further expanded. Conventionally, etching solutions used for thermoplastic resins such as polyester resin include dichromate-sulfuric acid mixture, chromic anhydride-sulfuric acid mixture, dichromic acid-phosphoric acid mixture, and dichromic acid-sulfuric acid mixture.
Strong oxidizing solutions such as a sulfuric acid-phosphoric acid mixture are known. Usually, such an etching solution corrodes and swells the resin surface, thereby creating recesses and achieving close contact between the plating film and the resin through a so-called anchor effect. However, when polyester resin is etched using a strong oxidizing solution such as the one described above, the resin surface cannot be sufficiently etched, resulting in insufficient anchoring effect and insufficient adhesion. There is. Means for Solving the Problems As a result of extensive research to find a method for plating polyester resin with good adhesion, the present inventor first brought the polyester resin into contact with a strong oxidizing solution during the etching process. It has been found that by subsequently bringing the resin into contact with a heterocyclic carbonate, the resin surface can be appropriately etched and a plating film with excellent adhesion can be obtained. That is, in the present invention, when a polyester resin is washed, etched, sensitized, activated, and electroless plated, the polyester resin is treated with a hexavalent chromium compound, sulfuric acid, and/or as an etching treatment. The present invention relates to a method for electroless plating of polyester resin, which is characterized by contacting a mixed solution with phosphoric acid and then contacting a heterocyclic alkylene carbonate having 1 to 8 carbon atoms or a solvent solution thereof. The polyester resin used in the present invention is a thermoplastic polyester such as polybutylene terephthalate, polyethylene terephthalate, polymethylene terephthalate, etc., and a filler added to these resins. Fillers used in polyester resin can generally be divided into inorganic fillers and organic fillers, and inorganic fillers include calcium carbonate,
Barium sulfate, activated calcium fluoride, calcium silicate, aluminum sulfate, calcium sulfate,
Magnesium sulfate, mica powder, talc, diatomaceous earth,
Examples include clay, dolomite, lithopone, alumina white, asbestos, pumice powder, graphite, and glass fiber. Examples of organic fillers include recycled rubber, ebonite powder, wood flour, and coconut/coconut shells. Examples include powder, cork powder, cellulose powder, cotton linters, wood pulp, paper, and cloth. In the present invention, first, the polyester resin object to be plated is washed and then brought into contact with a mixed solution of a hexavalent chromium compound and sulfuric acid and/or phosphoric acid. Although various methods are possible for contacting, a dipping method is usually used. This mixed solution is a strongly oxidizing solution that corrodes the resin surface.
It has a swelling effect. Hexavalent chromium compounds that can be used for this purpose include chromic anhydride;
Examples include dichromates such as potassium dichromate and sodium dichromate; chromates such as potassium chromate and sodium chromate. Examples of mixed solutions of hexavalent chromium compounds and sulfuric acid and/or phosphoric acid include (a) dichromate 5g/~35g/, 98% sulfuric acid 50ml/~700ml/, (b) chromic anhydride 50g/
~500g/, 98% sulfuric acid 100ml/~400ml/,
(c) Dichromate 5g/~35g/, 89% phosphoric acid
50ml/~700ml/, (d) dichromate 5g/
~35g/, 98% sulfuric acid 50ml/~700ml/, 89
Examples include solutions such as 50 ml/~300 ml/% phosphoric acid. Treatment conditions with a mixed solution of a hexavalent chromium compound and sulfuric acid and/or phosphoric acid vary depending on the type of resin and filler used, the concentration of the solution, etc., but it is usually about 3 to 20 minutes at a temperature of about 50 to 75 degrees Celsius. All you have to do is process it. In the present invention, after washing the resin treated with a mixed solution of a hexavalent chromium compound and sulfuric acid and/or phosphoric acid,
Contact with heterocyclic carbonate or its solvent solution. A resin that has only been treated with a mixed solution of a hexavalent chromium compound and sulfuric acid and/or phosphoric acid has unevenness on its surface, but the extent of the unevenness is small, so the adhesion to the electroless plating film is low.
However, by treatment with a heterocyclic carbonate, the resin surface further corrodes and swells, exhibiting a sufficient anchoring effect and providing excellent adhesion to the electroless plating film. In addition, when the polyester resin contains a filler, this treatment dissolves and removes the filler on the surface of the polyester resin, resulting in greater adhesion. The heterocyclic carbonate used here is a compound having a heterocycle and a carbonyl group, and a representative example thereof is a heterocyclic alkylene carbonate (the alkyl group is usually about C ₁ to C ₈ ). be able to. Specific examples include ethylene carbonate and propylene carbonate. Although these carbonate compounds can be used as they are in liquid form, they are usually used after being dissolved in a suitable solvent. Examples of the solvent in this case include water, lower alcohols such as methyl alcohol and ethyl alcohol, glycols such as ethylene glycol and propylene glycol, and ketones such as acetone, acetyl ketone, and methyl ethyl ketone, and these may be used in combination. You can also do that. Usually the concentration of heterocyclic compounds is 10
~300g/, preferably about 30-100g/. In addition, in the present invention, when treating a heterocyclic carbonate, by allowing a basic substance such as an alkali metal hydroxide or ammonia to coexist,
The effect of corroding and swelling the grease-proof surface can be further enhanced. Examples of the alkali metal hydroxide in this case include sodium hydroxide, potassium hydroxide, etc., and these are usually 50 to 300 g/, preferably 100 g/
It is used in an amount of ~200g/approximately. The conditions for treatment with heterocyclic carbonate are also 6
As with the treatment with chromium compound solution, it depends on the type of resin and the concentration of the solution, but usually the temperature
The treatment may be carried out at about 50 to 75°C for about 5 to 30 minutes. When carrying out the plating method of the present invention, the object to be plated is degreased by conventional means, washed with water, and then treated with a mixed solution of a hexavalent chromium compound and sulfuric acid and/or phosphoric acid. Next, the object to be treated is washed with water, subjected to heterocyclic carbonate treatment, and after washing with water, sensitized, activated, and electroless plating are performed according to conventional methods,
Perform electrolytic plating as necessary. As for sensitization, activation, electroless plating, and electrolytic plating, those conventionally used can be used as they are, and the conditions may be according to conventional methods. Furthermore, in the present invention, prior to the treatment with the hexavalent chromium compound solution and the treatment with the heterocyclic carbonate, it may be brought into contact with the heterocyclic carbonate or its solvent solution. By performing such treatment, the resin swells beforehand, so
The effects of the treatment with a valent chromium compound solution and the treatment with a heterocyclic carbonate can be further enhanced. The bath composition may be the same as that of the bath used for the heterocyclic carbonate treatment performed after the hexavalent chromium compound solution treatment, and the treatment may be performed at a temperature of about 50 to 75°C for about 5 to 15 minutes. Effects of the Invention According to the method of the present invention, it is possible to plate polyester resins with good adhesion, which has been difficult in the past, and its uses as engineering plastics with excellent heat resistance can be expanded. EXAMPLES Next, the present invention will be explained in more detail with reference to Examples. Example 1 As an inorganic filler, polybutylene terephthalate resin containing 30% by weight of glass fiber and calcium carbonate was molded at a molding temperature of 255 to 285°C and a mold temperature of 85 to 85°C.
A sample of 3 x 100 x 100 mm was prepared by molding at 120°C. This sample was immersed in an aqueous solution of 200 g of chromic anhydride and 200 ml of 98% sulfuric acid at 70°C for 10 minutes, washed with water, and then immersed in an aqueous solution of 50 g of propylene carbonate.
After immersion at 65°C for 10 minutes and washing with water, sensitization, activation, electroless plating, and electrolytic plating were performed according to conventional methods under the following conditions. Γ Sensitization: Catalyst solution (trademark “Catalyst C”,
(manufactured by Okuno Pharmaceutical Co., Ltd.) 60ml/36% hydrochloric acid
Γ Activation: Immerse in 100 ml of 98% sulfuric acid for 3 minutes at 40°C. Γ Electroless nickel plating: Electroless nickel plating (trademark: "TMP chemical nickel plating" manufactured by Okuno Pharmaceutical Co., Ltd.) ) for 8 minutes at 40℃ Copper sulfate plating: Copper sulfate 200g/, 98% sulfuric acid 28
Using a plating bath containing a small amount of brightener and a plating bath at 25° C. and 3 A/dm ² for 2 hours, plating Γ drying: 2 hours at 80° C. An adhesion test was conducted on the obtained plated product. The results are shown in Table 1. However, the adhesion was measured by the following method. Γ adhesion test: Make a 1 cm wide cut on the plating surface and use Autograph SD-100 manufactured by Shimadzu Corporation.
The adhesion was measured by peeling off the plating film while pulling it using C. Example 2 The same molded product as in Example 1 was treated with 200 g of chromic anhydride/
, immersed in an aqueous solution of 98% sulfuric acid 200 ml/at 70°C for 10 minutes, and after washing with water, propylene carbonate 50 g/
, immersed in an aqueous solution of 100 g of caustic soda at 65° C. for 10 minutes, washed with water, and treated in the same manner as in Example 1. Example 8 The same molded product as in Example 1 was treated with 200 g of chromic anhydride/
, immersed in an aqueous solution of 98% sulfuric acid 200 ml/at 70°C for 10 minutes, and after washing with water, propylene carbonate 50 g/
, caustic soda 200g/, ethylene glycol
It was immersed in a 150 g/aqueous solution at 65° C. for 10 minutes, washed with water, and then treated in the same manner as in Example 1. Example 4 The same molded product as in Example 1 was treated with sodium dichromate 15
g/, 98% sulfuric acid 500ml/, 89% phosphoric acid 100ml/
After immersing in an aqueous solution at 70℃ for 10 minutes and washing with water, ethylene carbonate 50g/, caustic soda 100g/
, 65℃ in an aqueous solution of ethyl alcohol 100g/
The sample was soaked in water for 10 minutes, washed with water, and treated in the same manner as in Example 1. Example 5 Aluminum silicate was used as an inorganic filler.
% (weight) of polybutylene terephthalate resin was molded at a molding temperature of 280°C and a mold temperature of 90°C to create a sample. This sample was added to an aqueous solution of 100 g of ethylene carbonate and 80 g of caustic soda.
After soaking at 70℃ for 5 minutes and washing with water, chromic anhydride 35
g/, in an aqueous solution of 450 ml of 98% sulfuric acid at 70°C.
Soaked for minutes. After washing with water, add 150 ml of caustic soda.
The sample was immersed in an aqueous solution containing 50 g/g/g of propylene carbonate and 50 g/g of ethylene glycol at 70°C for 5 minutes, washed with water, and then treated in the same manner as in Example 1. Example 6 Magnesium silicate was used as an inorganic filler.
% (weight) of polybutylene terephthalate resin was molded at a molding temperature of 285°C and a mold temperature of 90°C to prepare a sample. This sample was processed in the same manner as in Example 4. The appearance of the plating film was good, and the adhesion strength was 2.7 Kg/cm ² . Comparative Example 1 The same molded product as in Example 1 was degreased, and this sample was immersed in an aqueous solution of 200 g of chromic anhydride and 200 ml of 98% sulfuric acid at 70°C for 10 minutes, washed with water, and sensitized. Treated in the same way. Comparative Example 2 The same molded product as in Example 1 was degreased, and this sample was immersed in an aqueous solution of 200 g of chromic anhydride and 200 ml of 98% sulfuric acid at 70°C for 10 minutes, washed with water, and then soaked in caustic soda.
It was immersed in a 100 g/aqueous solution at 65° C. for 10 minutes, washed with water, and treated in the same manner as in Example 1 after sensitization. Comparative Example 3 The same molded product as in Example 5 was degreased, and the sample was treated with 50 g of propylene carbonate and 100 g of caustic soda.
Immerse it in an aqueous solution of
Each treatment after sensitization was performed in the same manner as in Example 1.

【table】

[Table] From Table 1, it is clear that the samples plated by the method of the present invention have a good appearance and the plated film has high adhesion strength. Example 7 A sample obtained by molding in the same manner as in Example 6 was immersed in an aqueous solution of 200 g of chromic anhydride/200 mg/g of 98% sulfuric acid at 70°C for 10 minutes, washed with water, and then immersed in an aqueous solution of 200 g/g of chromic anhydride and 200 mg/g of 98% sulfuric acid, washed with water, and then immersed in an aqueous solution of 200 g/g of chromic anhydride and 200 mg/g of 98% sulfuric acid. sodium oxide 200
The sample was immersed in an aqueous solution of 150 g/g/ethylene glycol at 65° C. for 10 minutes, washed with water, and subjected to various treatments after sensitization in the same manner as in Example 1. The appearance of the obtained electroless nickel plating film was good, and the adhesion strength after forming the copper plating layer was 2.2.
It was Kg/ ^cm2 . Example 8 A sample molded in the same manner as in Example 6 was immersed in an aqueous solution of 200 g of chromic anhydride and 200 ml of 98% sulfuric acid at 70°C for 10 minutes, washed with water, and then immersed in 30 g of hexylene carbonate and 200 ml of water. sodium oxide 200
The sample was immersed in an aqueous solution containing 150 g/g/g/ethylene glycol at 65° C. for 10 minutes, washed with water, and then subjected to various treatments after sensitization in the same manner as in Example 1. The appearance of the obtained electroless nickel plating film was good, and the adhesion strength after forming the copper plating layer was 2.1.
It was Kg/ ^cm2 . Example 9 A sample obtained by molding in the same manner as in Example 6 was mixed with 15 g of sodium dichromate, 500 ml of 98% sulfuric acid,
Immerse in an aqueous solution of 100 ml of 89% phosphoric acid at 70°C for 10 minutes, rinse with water, and then soak in octylene carbonate 10.
The sample was immersed in an aqueous solution containing 200 g of sodium hydroxide and 150 g of ethylene glycol at 65° C. for 10 minutes, washed with water, and subjected to sensitization and subsequent treatments in the same manner as in Example 1. The appearance of the obtained electroless nickel plating film was good, and the adhesion strength after forming the copper plating layer was 2.2.
It was Kg/ ^cm2 .

Claims (1)

[Claims] 1. When polyester resin is subjected to cleaning treatment, etching treatment, sensitization treatment, activation treatment, and electroless plating treatment, the polyester resin is
1. A method for electroless plating of polyester resin, which comprises contacting with a mixed solution of a valent chromium compound and sulfuric acid and/or phosphoric acid, and then contacting with a heterocyclic alkylene carbonate having 1 to 8 carbon atoms or a solvent solution thereof.