JPS6034638B2 - Thermoplastic product with partial metal plating - Google Patents

Description

Detailed Description of the Invention The present invention provides a thermoplastic resin product partially plated with metal using a thermoplastic resin composition consisting of a thermoplastic resin and selected carbon black, and a normal thermoplastic resin. It is related to.

BACKGROUND ART For the purpose of reducing costs and improving decorative effects, there has been a desire for products that are partially plated with metal only where necessary. For example, (1) a method of coating (masking) a paint that is not easily oxidized by an etching solution on parts that are not plated in advance, or plating the parts that are not plated in advance;
8357 and Jikosho 48-27917, plastic products partially plated with metal can be obtained by methods using plateable resins and non-plated resins (for example, plated and non-plated grades of polypropylene). ing.

However, these methods have problems such as 1) complicated steps and difficulty in masking, and 2) product defects due to differences in molding shrinkage rates. Furthermore, in cases where the surface of the plated area cannot be electrically connected to the surface of the plated area because it is surrounded by non-plated areas using these conventional methods, the above methods {1} and (2) cannot be used. Therefore, partially plated resin products cannot be obtained.

At present, a major problem remains that it is necessary to apply plating to the entire surface of the product, then leave only the necessary plated parts and paint the unnecessary parts. It should be noted that all products produced by any of these methods require the following steps: etching → neutralization → sensitizing (catalyst) → activating (accelerator) → electroless finishing → electroplating.

The present inventors have arrived at the present invention as a result of intensive research into simplification of processes, reduction of costs, etc.

That is, the present invention provides one or more thermoplastic resins 1
3 to 10 carbon blacks having a weight part of 0 and an oil absorption of 200 mm/ta or more and a surface area of 500 mm/ta or more
A thermoplastic resin composition consisting of parts by weight of This is a partially metal-plated thermoplastic resin product, which is characterized by directly applying electroplating to a two-color molded product molded using a method of etching.

To explain the present invention in more detail, the thermoplastic resin used in the present invention is a copolymer (ABS resin) consisting of vinyl cyanide, aromatic vinyl, and conjugated diene rubber.
, polypropylene resin, vinyl chloride resin, polystyrene resin, polycarbonate resin, methacrylic resin, polysulfone resin, polyester resin, polyacetal resin,
Polyamide resin, AS (aromatic vinyl cyanide) resin, polyphenylene oxide resin and EVA (
They are ethylene monovinyl acetate) resin and polyethylene resin, and they can be used alone or in combination of two or more.

In the case of two or more types, a mixture of polyphenylene oxide resin and polystyrene resin, a mixture of polypropylene resin and polyethylene resin, further, ABS resin and vinyl chloride resin, polycarbonate resin, methacrylic resin,
Examples include mixing with one or more resins selected from the group consisting of polysulfone resins, polyacetal resins, AS resins, and polyphenylene oxide resins.

Furthermore, the thermoplastic resin constituting the thermoplastic resin composition (1) of the present invention and the thermoplastic resin ' used for the non-plated part'
B} does not necessarily have to be the same type of thermoplastic resin.

For example, it may be a molded article in which the thermoplastic resin constituting the composition is an ABS resin, and the thermoplastic resin (B) in the non-plated portion is a polypropylene resin.

In addition, these thermoplastic resin compositions and thermoplastic resins (
Customary auxiliary agents such as lubricants, antioxidants, plasticizers, fillers, etc. may be added to B).

The carbon black used in the present invention has an oil absorption of 20
0 [/100 ta or more, and the surface area is 500 /
It is necessary that the

With carbon black outside this range, no matter which thermoplastic resin is used, even if electroplating is performed directly after etching, a haze film may not be formed, or even if it is formed, a good product cannot be obtained. The amount of carbon black per 10 parts by weight of thermoplastic resin in thermoplastic resin composition ① is 3
~100 parts by weight, and if it is 3 parts by weight or less, the oil absorption is 20 parts by weight or less.
Even if the carbon black has a surface area of 0/100 w/ta or more and a surface area of 500 w/ta or more, an exposed film cannot be formed.

In addition, if it exceeds 10 parts by weight, the thermoplastic resin composition will be damaged.
Its properties are extremely poor and it cannot be put to practical use. More preferably 5 to 7 parts by weight, most preferably 8 parts by weight.
~25 parts by weight.

In addition, oil absorption means a value measured according to JISK-6221-1975, and the amount of DBP (dibutyl phthalate) measured by an upsoap meter is expressed as
It is expressed in units of 00 evenings.

Surface area is a value measured according to ASTM D 3037-73 and is expressed in units of 1/2. If the oil absorption of carbon black is less than 200/100 ta or the surface area is less than 500/ta, a product with a satisfactory lightning deposit coating cannot be obtained. The volume resistivity value of the thermoplastic resin composition must be 1 pi or less.

If it exceeds 1 pi○/arc, a product with a satisfactory electrodeposited film cannot be obtained.

More preferably, it is less than or equal to 1 piQ.

In addition, the volume resistivity value is British Standard
It means a value measured according to rd2044 (Method 2).

The etching process may be chemical etching or physical etching.

Further, preliminary etching may be performed using a toluene-trichloride mixture before etching. According to the present invention, ■ there is no need for a masking process and the associated masking material; @ direct electroplating is possible after the etching process; Batting (accelerator) → Electroless adhesion plating process can be omitted, and the chemicals used in each process are also unnecessary. ■Furthermore,
Since these chemicals are not required, it is also beneficial in terms of waste liquid treatment.

In addition to molded products where it is impossible to make electrical contacts on the surface to be plated, even molded products whose periphery is surrounded by non-plated parts as shown in the drawing, we can make electrical contacts on the back side.
There are advantages such as the ability to obtain products that are partially plated with metal. Examples will be described below, but the present invention is not limited thereto.

Example 1 Thermoplastic resin and carbon black
Mix in the proportions shown in 1 to 3 and mix with a Banbury mixer.
00q0 was mixed for 8 minutes to obtain a thermoplastic resin composition.

Using this composition and a commercially available thermoplastic resin {B}, a two-color molded product as shown in the drawing was obtained using a 5-ounce injection molding machine. Next, apply 30% chromic anhydride to the molded product.
Etching treatment was carried out using Tanoku's concentrated sulfuric acid 500% solution (75qoxl), and electrical contacts were made at the locations shown in Figure 3.

After that, strike plating is performed directly on sulfuric acid steel at 200 m/s, sulfuric acid at 50 m/s and electric steel plating at a current density of IA/d, and then 3. Main plating (copper) was performed by increasing the current density to pine/d.

Further, nickel was plated at 4 A/d and chromium was plated at 3 A/d.

・ turtle, lotus ball

[Brief explanation of drawings]

FIG. 1 is a front view of a partially metal-plated thermoplastic resin product showing one embodiment of the present invention, and FIG. 2 is a cross-sectional view thereof. 1: Thermoplastic resin composition poor, 2: Thermoplastic resin 'B},
3: Electrical contact, 4: Metal plating film. Figure 1 Figure 2

Claims (1)

[Claims] 1. 100 parts by weight of one or more thermoplastic resins, an oil absorption of 200 ml/100 g or more, and a surface area of 500 m
A thermoplastic resin composition (A) consisting of 3 to 100 parts by weight of carbon black with a resistivity of ^2/g or more and a volume resistivity of 10^3 Ωcm or less is used for the part to be metal plated, and the non-plated part is Partially metal-plated thermoplastic, characterized in that it is a two-color molded product molded using one or more thermoplastic resins (B), which is then electroplated directly after etching treatment. resin products. 2. The partially metal-plated thermoplastic resin product according to item 1 above, wherein the thermoplastic resin is a copolymer consisting of vinyl cyanide, aromatic vinyl, and conjugated diene rubber. 3. The first above, wherein the thermoplastic resin is a polypropylene resin.
Thermoplastic resin products partially plated with metal as described in Section 1. 4 The first above, wherein the thermoplastic resin is a vinyl chloride resin.
Thermoplastic resin products partially plated with metal as described in Section 1. 5. The partially metal-plated thermoplastic resin product according to item 1 above, wherein the thermoplastic resin is polystyrene resin. 6. The partially metal-plated thermoplastic resin product according to item 1 above, wherein the thermoplastic resin is a polycarbonate resin. 7. The partially metal-plated thermoplastic resin product according to item 1 above, wherein the thermoplastic resin is a methacrylic resin. 8. The partially metal-plated thermoplastic resin product according to item 1 above, wherein the thermoplastic resin is a polysulfone resin. 9. The partially metal-plated thermoplastic resin product according to item 1 above, wherein the thermoplastic resin is a polyacetal resin. 10. The partially metal-plated thermoplastic resin product according to item 1 above, wherein the thermoplastic resin is a polyamide resin. 11. The partially metal-plated thermoplastic resin product according to item 1 above, wherein the thermoplastic resin is an aromatic vinyl-cyanide vinyl resin. 12. The partially metal-plated thermoplastic resin product according to item 1 above, wherein the thermoplastic resin is a polyphenylene oxide resin. 13. The partially metal-plated thermoplastic resin product according to item 1 above, wherein the thermoplastic resin is an ethylene-vinyl acetate resin. 14 The first above, wherein the thermoplastic resin is a polyethylene resin.
Thermoplastic resin products partially plated with metal as described in Section 1. 15. The partially metal-plated thermoplastic resin product according to item 1 above, wherein the thermoplastic resin is a mixture of polyphenylene oxide resin and polystyrene resin. 16. The partially metal-plated thermoplastic resin product according to item 1 above, wherein the thermoplastic resin is a mixture of polypropylene resin and polyethylene resin. 17 A copolymer in which the thermoplastic resin is composed of vinyl cyanide, aromatic vinyl, and conjugated diene rubber, vinyl chloride resin, polycarbonate resin, methacrylic resin, polysulfone resin,
The partially metal-plated resin according to item 1 above, which is a resin mixed with one or more resins selected from the group consisting of polyacetal resin, aromatic vinyl cyanide vinyl resin, and polyphenylene oxide resin. Thermoplastic resin product. 18. The partially metal-plated thermoplastic resin product according to items 2 to 17 above, wherein the carbon black is 5 to 70 parts by weight. 19. The partially metal-plated thermoplastic resin product according to item 18 above, which has a volume resistivity of 10^2 Ω·cm or less.