JPS6247458B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a conductive resin composition with excellent moldability that provides molded articles with excellent plating adhesion and which can be directly electroplated.

In recent years, synthetic resin products, which are lightweight, economical, and have excellent moldability, are being used instead of metal products, so the surface of these products has been coated with metal to give them light resistance, durability, etc. Among these, metal plating is one of the most important processing methods.

However, until now, metal plating methods have mainly been
It is applied to thermoplastic resins such as ABS resin and polypropylene, but since the heat resistance of thermoplastic resins is insufficient, thermosetting resins with good heat resistance are used in fields where heat resistance is required. There is a demand for the development of metal plated products.

As a method for providing metal-plated products made of phenolic resin in response to such demands, there is an electroless plating method as disclosed in, for example, Japanese Patent Publication No. 15733/1983. In this method, a phenolic resin molded product is degreased with alkali treatment, chemical etching, sensitizing, activating, electroless plating (electroless copper plating), and then electroplated (copper-nickel-chromium triple layer). This is a method of coating. However, this method has the disadvantage that it requires a variety of complicated pretreatment steps before electroplating, and water washing treatment accompanying these steps must be performed.Furthermore, it is difficult to regenerate the mixed solution used for etching. The problem was that it required a considerable amount of effort.

Therefore, in order to eliminate the complicated pretreatment process mentioned above,
A method has been proposed in which carbon black is added to a thermosetting resin such as phenol resin, which is a nonconductor, to make the resin conductive, and then electroplating is performed directly. However, although this method produces a plating film, the adhesion of the plating film to the thermosetting resin base is almost non-existent, and it has not been possible to obtain a product that can be put to practical use.

The inventors of the present invention have conducted extensive research to overcome the drawbacks of conventional metal plating methods, especially electroplating methods. As a result, they have added carbon black and a predetermined amount of sulfur to a thermosetting resin containing a phenolic resin and a base material. After molding a phenolic resin composition obtained by blending and trithiol cyanuric acid, if the molded product is electroplated directly, a uniform plating film with excellent adhesion to the thermosetting resin base can be formed. I discovered that. The present invention was completed based on this knowledge.

That is, the present invention is based on (A) 100 parts by weight of a thermosetting resin consisting of a phenolic resin and a base material, (B) 5 to 30 parts by weight of carbon black, (C) 0.1 to 6 parts by weight of sulfur, and (D) trithiol. The present invention provides a conductive phenolic resin composition characterized by containing 0.1 to 5 parts by weight of cyanuric acid.

The phenolic resin used in the composition of the present invention may be either a novolac type or a resol type, or a combination thereof. A suitable base material is added to this phenolic resin. As the base material, organic and inorganic fillers such as wood flour, glass fiber, cotton cloth, and glass fiber cloth can be used alone or in combination. The amount of the base material is not particularly limited, but is generally used in a range of about 50 to 200 parts by weight per 100 parts by weight of the phenolic resin.

The carbon black used in the composition of the present invention may be any commercially available carbon black, such as acetylene black, furnace black, thermal black, conductive carbon black, etc. Among them, conductive carbon black is particularly preferred in terms of conductivity. The amount of carbon black to be added is preferably 5 to 30 parts by weight per 100 parts by weight of the thermosetting resin consisting of component (A), the phenolic resin and the base material. If the amount of carbon black is more than 30 parts by weight, the composition will be too hard and will have poor fluidity during molding. Furthermore, if the amount of carbon black is less than 5 parts by weight, the electrical resistance becomes too high and the plating properties deteriorate.

The sulfur used in the composition of the present invention may be in any modified form as long as it is a simple substance, and powdered sulfur is convenient for use. The amount of sulfur added is 0.1 to 6 parts by weight, preferably 0.3 to 3 parts by weight, per 100 parts by weight of the thermosetting resin of component (A). If the sulfur content is less than 0.1 part by weight, the plating adhesion will decrease, and if the sulfur content exceeds 6 parts by weight, the plating adhesion will similarly decrease.

In the composition of the present invention, addition of trithiol cyanuric acid is essential in order to obtain uniform and good plating adhesion. Similarly, the amount of trithiol cyanuric acid added is 100% of the thermosetting resin of component (A).
0.1 to 5 parts by weight, preferably 0.3 to 5 parts by weight
The range is 2 parts by weight. If the amount added is less than 0.1 part by weight, the good plating adhesion improvement effect of the present invention, especially the effect of preventing variation in adhesion strength depending on the molded part of the molded product, cannot be obtained, and if the amount is less than 6 parts by weight, If the amount exceeds that amount, the effect of improving adhesion strength and making it more uniform cannot be expected by further increasing the amount added.

The conductive phenolic resin composition of the present invention is produced by kneading these components (A), (B), (C), and (D). For kneading, roll kneading, which is commonly performed in the industry, is used. The kneading temperature is preferably as low as possible to avoid thermal decomposition of the polymer.

In producing this composition, a stabilizer against oxygen, a deterioration inhibitor, a filler, a lubricant, a blowing agent, and a flame retardant which are commonly used during molding of the phenolic resin may be added as appropriate.

The electrical resistance of the conductive phenolic resin composition of the present invention obtained in this way depends on the type of phenolic resin, carbon black, etc. employed, but is usually a value of 1000 Ω-cm or less. From the viewpoint of workability during plating, it is desirable that the resistance be 300 Ω-cm or less.

The conductive resin composition of the present invention can be molded by applying a conventional molding method for thermosetting resins. For example, compression molding, transfer molding, or injection molding methods can be applied, and molding can be performed at a resin temperature in the range of 130 to 250°C.

The molded article obtained from the resin composition of the present invention can be plated, for example, by washing with a weak alkaline detergent and washing with water, and then first applying low voltage using a Watt bath. Perform plating for 3 minutes at 1volt and 3 minutes at 1.5volt. The plating film thus formed on the molded article of the composition of the present invention has extremely excellent adhesion. Next, the film thickness is 3μm at 4-5A/ ^dm2 .
Stir for 5 to 10 minutes until it becomes nickel strike. From then on, normal electroplating conditions can be applied as is. For example, plating such as nickel strike plating (3 μm) + copper plating (10 μm) + nickel plating (10 μm) + chrome plating (0.1 μm) can be performed.

Application examples of plastic plating of articles using the resin composition of the present invention include knobs, bottle caps, wheel caps, automobile lamp housings, grills, trims, nameplates, etc. Especially for knobs, multi-piece molding is possible.

The conductive phenolic resin composition of the present invention has good moldability, and if this molded article is used, electroplating can be performed directly, and the formed plating film has uniform and excellent adhesion.

Next, the present invention will be explained in more detail based on examples.

In the examples, the electrical resistance of the resin was determined by measuring the resistance over a 1 cm distance on the surface of the molded product using a tester. In addition, the adhesion strength between the plating film and the resin is 1cm wide on the plating layer.
A notch was made, and one end was attached to a spring scale and peeled off at a 90° angle, and the reading was read.

Example As a thermosetting resin containing a phenolic resin and a base material, 12 parts by weight of hexamine (curing agent) and wood powder (base material) were added to 100 parts by weight of Novolac resin (brand #2000) manufactured by Mitsui Toatsu Chemical Co., Ltd. A mixture of 100 parts by weight and 1 part by weight of stearic acid (mold release agent)
Using 100 parts by weight, add 22 parts by weight of carbon black (manufactured by Lion Akzo Co., Ltd., Ketchen Black), 1 part by weight of sulfur, and trithiol cyanuric acid.
Add 0.5 parts by weight and mix using a ribbon mixer. After thoroughly mixing this mixture with a hot roll, it is pulverized with a pulverizer (particle size of about 500 μm) to obtain a molding material composition. Next, using this composition, a disk having a diameter of 150 mm and a thickness of 3 mm was manufactured by injection molding. The electrical resistance of this disk was 10 Ω-cm. Next, this disc was heated using a Watts bath.
Nickel plating was performed by electroplating at 1 A/dm ² for 5 minutes. Furthermore, copper plating was performed thereon to form a copper plating layer with a thickness of 50 μm. Cuts of 1 cm width and 6 cm length were made in three places parallel to the gate side at 3 cm intervals on the plating sample obtained in this way, and the plating adhesion strength was measured as 0.7, 0.8, and 0.7 Kg/cm, respectively. It was uniform and warm.

Comparative Example 1 A molding material composition was prepared in the same manner as in the example except that trithiol cyanuric acid was not added, and a disk was molded. The electrical resistance of the obtained disk is 10Ω−
It was cm. After nickel plating and copper plating were applied under the same conditions as in the example, the adhesion strength between the plating film and the resin was measured at three locations as in the example, and it was found to be 0, 0.1, and 0 kg/cm, respectively.

Comparative Example 2 Same as Example except that sulfur was not added,
A molding material composition was prepared, a disk was formed, it was applied to the disk in the same manner as in the example, and the adhesion strength of the plating film was measured in the same manner as in the example. , 0 kg/cm.

Claims (1)

[Claims] 1 (A) 100 parts by weight of a thermosetting resin consisting of a phenolic resin and a base material, (B) 5 to 30 parts by weight of carbon black, (C) 0.1 to 6 parts by weight of sulfur, and (D) Tori. An electrically conductive phenolic resin composition containing 0.1 to 5 parts by weight of thiol cyanuric acid.