USING THE SAME

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to, and benefits of Chinese Patent Application No.

201010117125.4 filed with State Intellectual Property Office, P. R. C. on February 26, 2010, the entire content of which is incorporated herein by reference.

FIELD

The present disclosure relates to a method for preparing a plastic article and a plastic article made using the method.

BACKGROUND

Metalization process is used for forming a metal layer onto a non-metal substrate such as a plastic substrate by coating or depositing. Without wishing to be bound by theory, it is considered that the metalization process may improve the ability of the substrate to transmit or transfer electric and/or magnetic signals.

A plastic substrate having a metal layer on its surface as a pathway of electromagnetic signal conduction is widely used in automobiles, industries, computers, telecommunications, etc. Selectively forming a metal layer is one of the important processes for preparing such plastic articles. The conventional method for forming a metal layer is usually realized by forming a metal core as a catalytic center on the surface of the plastic substrate so that the subsequent chemical plating may be performed. However, processes related thereto are complex where strict demand on equipment is needed, whereas the energy consumption is high. Further, there is a low adhesive force between the coating layer and the plastic substrate.

SUMMARY

The present disclosure is directed to solve at least one of the problems existing in the prior art. Accordingly, a method for preparing a plastic article is provided, in which the plastic metallization is easily performed with lower energy consumption and enhanced adhesive force between the metal layer and the plastic substrate. Further, a plastic article made using the same is provided, in which the adhesive force between the coating layer and the plastic or non-metal substrate is enhanced.

According to an aspect of the present disclosure, a method for preparing a plastic article is provided. The method comprises steps of: providing a plastic substrate made from a plastic comprising an accelerator dispersed therein; irradiating a predetermined area on a surface of the plastic substrate to expose the accelerator in the predetermined area; plating the irradiated area on the surface of the plastic substrate to form a first metal layer on the predetermined area; and plating the first metal layer to form a second metal layer on the first metal layer. The accelerator is represented by formulas of AMxByOz and/or AM _m O _n . In the formula of AM _x B _y O _z , A is at least one element selected from Group 10 and Group 11 of the Periodic Table of Elements; M is at least one trivalent metallic element selected from the group consisting of Fe, Co, Mn, Al, Ga, In, Tl, and rare earth elements; 0 is oxygen; x=0-2, y=0.01 -2; and z=1 -4. In the formula of A'M' _m O _n , A' is at least one element selected from Group 9, Group 10, and Group 11 of the Periodic Table of Elements; I is at least one element selected from the group consisting of Cr, Mo, W, Se, Te, and Po; O is oxygen; m=0.01 -2; and n=2-4.

According to another aspect of the present disclosure, a plastic article is provided, comprising: a plastic substrate comprising an accelerator; and first and second metal layers on the surface of the plastic substrate. The accelerator is represented by formulas of AMxByOz and/or A'M' _m O _n . In the formula of AM _x B _y O _z , A is at least one element selected from Group 10 and Group 11 of the Periodic Table of Elements; M is at least one trivalent metallic element selected from the group consisting of Fe, Co, Mn, Al, Ga, In, Tl, and rare earth elements; O is oxygen; x=0-2, y=0.01 -2; and z=1 -4. In the formula of A'M' _m O _n , A' is at least one element selected from Group 9, Group 10, and Group 11 of the Periodic Table of Elements; M' is at least one element selected from the group consisting of Cr, Mo, W, Se, Te, and Po; O is oxygen; m=0.01 -2; and n=2-4.

As found by the inventors that, selectively chemical plating may be directly performed on the surface containing the accelerator, and the plastic will not be degraded by the accelerator represented by a general formula of AM _x B _y O _z or A'M' _m O _n , without reducing metal oxides into pure metals. According to an embodiment of the present disclosure, the accelerator may be distributed evenly in the plastic substrate, and a predetermined area on the surface of the plastic substrate may be gasified by, for example, laser to expose the accelerator so that the accelerator may be reduced into pure metal without high energy consumption. Furthermore, electroplating or chemical plating may be performed to form the desired metal layer, thus achieving the selective surface metallization with simple process, lower energy consumption and reduced cost. In addition, the accelerator may be evenly distributed in the plastic substrate, so that the adhesive force between the coating layer and the plastic substrate after chemical plating is high, thus improving the quality of the plastic article as manufactured therefrom.

Additional aspects and advantages of the embodiments of present disclosure will be given in part in the following descriptions, become apparent in part from the following descriptions, or be learned from the practice of the embodiments of the present disclosure. DETAILED DISCRETION OF THE EMBODIMENT

Reference will be made in detail to embodiments of the present disclosure. The embodiments described herein are explanatory, illustrative, and used to generally understand the present disclosure. The embodiments shall not be construed to limit the present disclosure. The same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions.

In an illustrative, non-limiting, embodiment of the present disclosure, a method for preparing a plastic article is provided. The method may comprise the steps of: providing a plastic substrate made from a plastic comprising an accelerator dispersed therein. The accelerator may have a formula of AM _x B _y O _z , in which: A is at least one element selected from Group 10 and Group 11 of the Periodic Table of Elements; M is at least one trivalent metallic element selected from the group consisting of Fe, Co, Mn, Al, Ga, In, Tl, and rare earth elements; O is oxygen; x=0-2, y=0.01 -2; and z=1 -4. The accelerator may have an alternative formula of A'M' _m O _n , in which: A' is at least one element selected from Group 9, Group 10, and Group 11 of the Periodic Table of Elements; M' is at least one element selected from the group consisting of Cr, Mo, W, Se, Te, and Po; O is oxygen; m=0.01 -2; and n=2-4. The method may further comprise the steps of irradiating a predetermined area on a surface of the plastic substrate optionally by laser to expose at least a part of the accelerator; plating the irradiated area on the surface of the plastic substrate to form a first metal layer on the predetermined area; and then plating the first metal layer to form a second metal layer on the first metal layer.

Accelerator

In an illustrative, non-limiting, embodiment, the accelerator may have a formula AMxByOz, in which: A is at least one element selected from Group 10 and Group 11 of the Periodic Table of Elements; M is at least one trivalent metallic element selected from the group consisting of Fe, Co, Mn, Al, Ga, In, Tl, and rare earth elements; 0 is oxygen; x=0- 2, y=0.01 -2; and z=1 -4. The accelerator may have an alternative formula of AM _m O _n , in which: A' is at least one element selected from Group 9, Group 10, and Group 11 of the Periodic Table of Elements; I is at least one element selected from the group consisting of Cr, Mo, W, Se, Te, and Po; O is oxygen; m=0.01 -2; and n=2-4. For example, the accelerator may have a formula of AM _x B _y O _z , in which A may be Cu or Ni. Particularly, suitable accelerator may be selected from the group consisting of: CuFeo.5Bo.5O2 5, CuNio.5Bo.5O25, CuAI0.5B0.5O2 5, CuGao.5Bo.5O25, CuB ₂ O ₄ and CUB0.7O2. The accelerator may have an alternative formula of A'M' _m O _n , in which A' may be Co, Ni or Cu. Particularly, suitable accelerator may include, without limitation, CUM00.7O3, CUM00.5O2.5, CuMoO ₄ , CuWO ₄ or CuSeO ₄ .

Without wishing to be bound by theory, it is considered that the accelerator represented by a general formula of AM _x B _y O _z or A'M' _m O _n may favor direct copper-plating or nickel-plating, and may serve to avoid or mitigate plastic degradation.

In a non-limiting embodiment, the accelerator may have an average diameter of about 20 nm to about 100 m, particularly about 50 nm to about 10 m, more particularly about 200 nm to about 4 m. The amount of the accelerator may be about 1 wt% to about 40 wt% of the plastic substrate, particularly about 1 wt% to about 30 wt%, more particularly about 2 wt% to about 15 wt%.

In a further illustrative, non-limiting, embodiment, the accelerator may be uniformly dispersed within the plastic. Without wishing to be bound by theory, it is considered that uniform dispersion of the accelerator in the plastic aids in forming a strong adhesion between the metal layer and the plastic substrate. The accelerator may be any compound well-known to those skilled in the art. The accelerator may be commercially available, for example, may be CuW0 ₄ commercially available from Guangzhou Weibo Chemical Co., Ltd., P. R. C, or CuSe0 ₄ commercially available from Mitsuwa Chemical Co., Ltd. Moreover, the accelerator may be self- prepared, and methods for preparing suitable accelerator are well-known to those skilled in the art. For example, a method for preparing CuGao.5Bo.5O2 5 comprises the steps of: mixing and ball milling 58 g of CuO, 34 g of Ga ₂ O3 and 14 g of Β ₂ Οβ to form a mixture; calcining the mixture at a temperature of about 1000°C for about 2 h to form the accelerator with an average particle diameter of about 1 .0 m to about 2.5 m and a composition of CuGao.5Bo.5Oz5 as tested by ICP-AES. Similarly, a method for preparing CuMoO ₄ comprises the steps of: mixing and ball milling 36 g of CuO and 65 g of ΜοΟβ ίο form a mixture; and calcining the mixture at a temperature of about 800°C for about 2 h to form the accelerator with a composition of CuMoO ₄ as tested by XRD.

It is shown by a lot of research that, except that pure metal, such as pure Cu and Pd, may be used as the nucleus or grain for chemical plating, nano-CuO may largely improve the chemical deposition speed of the metal atoms on the plastic surface during chemical plating. It has been found by the inventors that nano-CuO particles with an average particle size of about 40 nm commercially available from Aladin Reagent Co., Ltd. in a conventional chemical plating solution may cause fast deposition of Cu on the surface of nano-CuO particles. However, nano-CuO may also cause the degradation of the plastic. By many experiments, it has been found by the inventors that the accelerator represented by the general formula of AM _x B _y O _z or A'M' _m O _n may be used for surface treatment, and such accelerator may promote the chemical deposition of Cu or Ni on the surface of the accelerator, without causing the degradation of the plastic while remained in the plastic for a long time.

According to an embodiment of the present disclosure, the accelerator may be evenly distributed in the plastic substrate, the adhesive force between the accelerator and the plastic substrate is very high so that the subsequent chemical plating may be performed on the surface of the accelerator directly. As a result, the adhesive force between the coating layer and the plastic substrate may be increased tremendously.

Plastic In an illustrative, non-limiting, embodiment, the plastic may be a thermoplastic plastic or a thermosetting plastic. The thermoplastic plastic may be selected from the group consisting of polyolefins, polycarbonates (PC), polyesters, polyamides, polyaromatic ethers, polyester-imides, polycarbonate/acrylonitrile-butadiene-styrene composite (PC/ABS), polyphenylene oxide (PPO), polyphenylene sulfide (PPS), polyimides (PI), polysulfones (PSU), poly (ether ether ketone) (PEEK), polybenzimidazole (PBI), liquid crystalline polymer (LCP) and any combination thereof. The polyolefins may be selected from polystyrene (PS), polypropylene (PP), polymethyl methacrylate (PMMA) or poly(acrylonitrile-butadiene-styrene) (ABS). The polyesters may be selected from polycyclohexylene dimethylene terephthalate (PCT), poly(diallyl isophthalate) (PDAIP), poly(diallyl phthalate) (PDAP), polybutylene naphthalate (PBN), Poly(ethylene terephthalate) (PET), or polybutylene terephthalate (PBT). The polyamides may be selected from polyhexamethylene adipamide (PA-66), poly(hexamethylene azelamide) (PA-69), polyhexamethylene succinamide (PA-64), poly(hexamethylene dodecanoamide) (PA-612), poly(hexamethylene sebacamide) (PA-610), poly(decametylene sebacamide) (PA-1010), polyundecanoamide (PA-11 ), polydodecanoamide (PA-12), polycapryllactam (PA-8), poly(9-amino nonanoic acid) (PA- 9), polycaprolactam (PA-6), poly(p-phenytene terephthalamide) (PPTA), poly-m-xylylene adipamide (MXD6), polyhexamethylene terephthalamide (PA6T), or poly(nonamethylene terephthalamide) (PA9T). The liquid crystalline polymer (LCP) may be a polymer comprising rigid chains and being capable of forming regions of highly ordered structure in the liquid phase. The thermosetting plastic may be selected from the group consisting of phenolic resin, urea-formaldehyde resin, melamine-formaldehyde resin, epoxy resin, alkyd resin, polyurethane and any combination thereof.

Dispersion of Accelerator in Plastic

In an illustrative, non-limiting, embodiment, the accelerator may be dispersed within the plastic by mixing followed, without limitation, by an optional molding process. In some embodiments, the accelerator may be dispersed in the plastic by using an internal mixer, a singer screw extruder, a twin screw extruder or a mixer. In some embodiments, the term "plastic substrate" means a plastic having accelerator disposed or dispersed therein. After the dispersion of the accelerator in the plastic, the plastic substrate may be formed into various kinds of shapes by injection molding, blow molding, extraction molding, or hot press molding.

Additives

In illustrative, non-limiting, embodiments, the plastic substrate may further comprise at least one well-known commercially available additive selected from the group consisting of: an antioxidant, a light stabilizer, a lubricant, and an inorganic filler.

In a non-limiting embodiment, the antioxidant may be antioxidant 1098, 1076, 1010, or 168 available from Ciba Specialty Chemicals. The amount of the antioxidant may be about 0.01 wt% to about 2 wt% of the plastic substrate. The antioxidant may enhance the oxidation resistance of the plastic substrate.

The light stabilizer may be any commercially available light stabilizer, particularly a hindered amine light stabilizer, such as light stabilizer 944 available from Ciba Specialty Chemicals. The amount of the light stabilizer may be about 0.01 wt% to about 2 wt% of the plastic substrate. The light stabilizer may enhance the light stability of the plastic substrate.

In a non-limiting embodiment, the lubricant may be selected from the group consisting of: methylpolysiloxanes, EVA waxes formed from ethylene and vinyl acetate, polyethylene waxes, stearates, and any combination thereof. The amount of the lubricant may be about 0.01 wt% to about 2 wt% of the plastic substrate. The lubricant may enhance the fluidity of the plastic so that the plastic substrate may be evenly mixed.

In a non-limiting embodiment, the inorganic filler may be selected from the group consisting of talcum powder, calcium carbonate, glass fiber, calcium silicate fiber, tin oxide, and carbon black. The glass fiber may increase the etched depth of the plastic substrate while being irradiated by laser, which is favorable for the adhesion of Cu during chemical Cu-plating. The tin oxide, especially nano tin oxide, or carbon black may enhance the energy utilization rate of the laser. In further embodiments, the inorganic filler may be those selected from the group consisting of glass bead, calcium sulfate, barium sulfate, titanium dioxide, pearl powder, wollastonite, diatomite, kaolin, pulverized coal, pottery clay, mica, oil shale ash, aluminosilicate, alumina, carbon fiber, silicon dioxide, zinc oxide, and any combination thereof; particularly those without harmful elements such as Cr to the environment and the human health. The amount of the inorganic filler may be about 1 wt% to about 70 wt% of the plastic substrate. Irradiation

In an illustrative, non-limiting, embodiment, a predetermined area on the surface of the plastic substrate is irradiated to expose at least a part of the accelerator. According to an embodiment of the present disclosure, the desired pattern may be formed on the surface of the plastic substrate by the method of the present disclosure. In an embodiment, irradiation may be achieved by exposing a predetermined area on the surface of the plastic substrate to laser. In an embodiment, a predetermined area on the surface of the plastic substrate may be irradiated optionally by laser to expose the accelerator. The laser equipment may be a conventional infrared laser, such as a CO2 laser marking system. In a non-limiting embodiment, the laser may have a wavelength of about 157 nm to about 10.6 m, a scanning speed of about 500 mm/s to about 8000 mm/s, a scanning step of about 3 m to about 9 m, a scan time delay of about 30 με to about 100 με, a frequency of about 30 KHz to about 40 KHz, a power of about 3 W to 4 W, and a filled distance of about 10 m to about 50 m. According to some embodiments of the present disclosure, the power of the laser may be sufficient to expose the accelerator, without altering or damaging the accelerator, or reducing the accelerator to pure metal.

In a non-limiting embodiment, the plastic substrate may have a thickness of more than about 500 Mm, and the depth of the irradiated part of the plastic substrate may be less than about 20 Mm, so that the accelerator may be exposed to form a microscopic and coarse surface having rugged voids. During the subsequent chemical copper or nickel plating process, copper or nickel may be embedded into the voids in the coarse surface, thus forming strong adhesive force with the plastic substrate. In an embodiment, the areas without the accelerator are not irradiated, and, without wishing to be bound by theory, it is considered that these areas may have low deposition speed and poor adhesion. While a few metals may be deposited on these areas, they may be easily removed by, for example and without limitation, ultrasonic cleaning. In this manner, it is considered that, without wishing to be bound by theory, the metalization may be controlled in required areas on the surface of the plastic substrate.

The predetermined area may be the whole surface of the plastic substrate or a part of the surface of the plastic substrate.

The gasifying of the plastic substrate may cause plastic smoke, which may drop down and cover the exposed accelerator. In a further illustrative, non-limiting, embodiment, a ventilating device may be applied to remove any mist generated or introduced during the irradiation process. Additionally, in some non-limiting embodiments, the plastic substrate may be ultrasonically cleaned after laser irradiation.

According to an embodiment of the present disclosure, there are substantially no chemical plating deposits on the surface of the plastic substrate where no accelerators exist. Thus, the electroplating speed is very low with weak adhesive force. Even if there are few chemical deposits, they may be removed easily. Thus, direct selective surface metalizing method may be achieved easily according to the present disclosure.

First Plating

In an embodiment, after irradiation, the accelerator may be exposed in the predetermined area on the surface of the plastic substrate. Chemical copper and/or nickel plating may be performed on the surface of the accelerator, which may result in a relatively strong adhesion between the plastic substrate and the plating layers.

In a non-limiting embodiment, after laser irradiation, the accelerator may be exposed in the irradiated areas. Thereafter, copper-plating or nickel-plating may be performed on the surface of the accelerator. The copper-plating or nickel-plating method is well known to those skilled in the art, for example, contacting the irradiated plastic substrate with a copper-plating or nickel-plating solution (described below). Without wishing to be bound by theory, It is considered that that the exposed accelerator may favor the copper or nickel ions to be reduced to copper or nickel powders, which may cover the surface of the accelerator and form a dense copper or nickel layer on the surface of the accelerator rapidly.

Further Plating

In a non-limiting embodiment, after the first plating, one or more chemical or electroplating layers may be applied to the copper or nickel layer. For example, after a first nickel layer is formed on the surface of the accelerator, a copper layer may be formed on the first nickel layer by chemical plating, and then a second nickel layer may be formed on the copper layer by chemical plating to form a composite plastic article having a structure of Ni-Cu-Ni. Particularly, an aurum layer may be formed on the composite plastic article by flash plating to form a plastic article having a structure of Ni- Cu-Ni-Au.

In a further illustrative, non-limiting, embodiment, after a first copper layer is formed on the surface of the accelerator, a nickel layer may be formed on the first copper layer by plating to form a structure of Cu-Ni. Particularly, an aurum layer may be formed on the Cu-Ni layer by flash plating to form a structure of Cu-Ni-Au.

In some non-limiting embodiments, the nickel layer may have a thickness ranging from about 0.1 m to about 50 m, particularly from about 1 m to about 10 Mm, more particularly from about 2 Mm to about 3 Mm. The copper layer may have a thickness ranging from about 0.1 Mm to about 100 Mm, particularly from about 1 Mm to about 50 Mm, more particularly from about 5 Mm to about 30 Mm. The aurum layer may have a thickness ranging from about 0.01 Mm to about 10 Mm, particularly from about 0.01 Mm to about 2 Mm, more particularly from about 0.1 Mm to about 1 Mm.

The chemical copper and nickel plating solutions, the copper and nickel electroplating solutions and the aurum flash plating solution are well known to those skilled in the art. In a non-limiting embodiment, the chemical copper plating solution may comprise a copper salt and a reducing agent, with a pH value ranging from about 12 to about 13. The reducing agent may reduce the copper ion to pure copper. The reducing agent may be selected from the group consisting of glyoxylic acid, hydrazine, sodium hypophosphite and any combination thereof. In another embodiment, the chemical plating solution having a pH value of about 12.5 to about 13 adjusted by NaOH and H ₂ S0 ₄ may comprise 0.12 mol/L of CuS0 ₄ -5H ₂ 0, 0.14 mol/L of Na ₂ EDTA-2H ₂ 0, 10 mg/L of potassium ferrocyanide, 10 mg/L of 2,2'-bipyridine, and about 0.10 mol/L of glyoxylic acid (HCOCOOH) solution. In a non-limiting embodiment, the copper plating may be performed for about 10 min to about 240 min. The chemical plating solution having a pH value of about 5.2 adjusted by NaOH at a temperature of about 85°C to about 90°C may comprise 23 g/L of nickel sulfate, 18 g/L of sodium hypophosphite, 20 g/L of lactic acid, and 15 g/L of malic acid. In a non-limiting embodiment, the nickel plating may be performed for about 8 min to about 15 min.

Aurum flash plating is well known to those skilled in the art. In a non-limiting embodiment, the flash plating solution may be a BG-24 neutral aurum plating solution, which is commercially available from Shenzhen Jingyanchuang Chemical Company, P. R. C.

A plastic article comprises the plastic substrate described above, and first and second metal layers on the surface of the plastic substrate. The first metal layer is an Ni layer and the second metal layer is Cu-Ni or Cu-Ni-Au layers, or the first metal layer is a Cu layer and the second metal layer is Ni or Ni-Au layers. Each nickel layer has a thickness ranging from about 0.1 m to about 50 m; each copper layer has a thickness ranging from about 0.1 m to about 100 Mm; and each aurum layer has a thickness ranging from about 0.01 Mm to about 10 Mm.

Additional details of the present disclosure will be provided as follows by some embodiments of the present disclosure.

Embodiment 1

A method for preparing a plastic article comprises the following steps.

a) CuFeo.5Bo.5O2 5 was ball milled in a high speed ball grinder for about 10 h to form powders with an average diameter of about 700 nm; then PP resin, CuFeo.5Bo.5O2 5 powders, calcium silicate fiber, and antioxidant 1010 according to a weight ratio of about 100: 10: 30: 0.2 were mixed in a high speed mixer to prepare a mixture; then the mixture was extruded and granulated by a twin screw extruder available from Nanjing Rubber & Plastics Machinery Plant Co., Ltd., P. R. C, then injection molded to form a substrate of a circuit board for a LED (light emitting diode) lamp.

b) A metal circuit pattern was curved on the substrate by a DPF-M12 infrared laser available from Shenzhen TEC-H LASER Technology Co., Ltd., P. R. C. with a wavelength of about 1064 nm, a scanning speed of about 1000 mm/s, a scanning step size of about 9 Mm, a scan time delay of about 30 MS, a frequency of about 40 KHz, a power of about 3 W, and a filled distance of about 50 Mm. The surface of the plastic article was then ultrasonically cleaned.

c) The substrate was immersed in a chemical nickel plating solution for about 10 min to form a first nickel layer with a thickness of about 3 Mm; the substrate was then immersed in a chemical copper plating solution for about 4 h to form a copper layer with a thickness of about 13 Mm on the first nickel layer; thereafter the substrate was again immersed in the chemical nickel plating solution for about 10 min to form a second nickel layer with a thickness of about 3 μηι on the copper layer; finally the substrate was flash plated with an aurum layer with a thickness of about 0.03 μηι on the second nickel layer to form the plastic article as the substrate for a circuit board of a LED lamp. The copper plating solution was comprised of about 0.12 mol/L of CuSO ₄ -5H ₂ O, about 0.14 mol/L of Na ₂ EDTA-2H ₂ O, about 10 mg/L of potassium ferrocyanide, about 10 mg/L of 2,2'- bipyridine, and about 0.10 mol/L of glyoxylic acid (HCOCOOH), with a PH value of about 12.5 to about 13 adjusted by NaOH and H ₂ S0 ₄ . The nickel plating solution was comprised of about 23 g/L of nickel sulfate, about 18 g/L of sodium hypophosphite, about 20 g/L of lactic acid, and about 15 g/L of malic acid, with a PH value of about 5.2 adjusted by NaOH. The aurum strike plating solution was BG-24 neutral aurum plating solution commercially available from Shenzhen Jingyanchuang Chemical Company, P. R. C.

Embodiment 2

The method in Embodiment 2 is substantially similar to that in Embodiment 1 , with the exception of the following respects.

In step a), CuB ₂ O ₄ was ball milled to form powders with an average diameter of about 800 nm; the powders were dried and mixed with PEEK resin, glass fiber, and antioxidant 168 according to a weight ratio of about 20: 100: 30: 0.2 in a high speed mixer to prepare a mixture; then the mixture was extruded and granulated, then injection molded to form a substrate.

In step c), the substrate was immersed in a chemical nickel plating solution for about 8 min to form a first nickel layer with a thickness of about 2 m; thereafter the substrate was immersed in a chemical copper plating solution for about 4 h to form a copper layer with a thickness of about 13 m on the first nickel layer; then the substrate was again immersed in the chemical nickel plating solution for about 10 min to form a second nickel layer with a thickness of about 3 m on the copper layer; finally the substrate was flash plated with an aurum layer with a thickness of about 0.03 Mm on the second nickel layer to form the plastic article as a shell for an electronic connector of an automobile motor.

Embodiment 3 The method in Embodiment 3 is substantially similar to that in Embodiment 1 , with the exception of the following respects.

In step a), CuW0 ₄ was ball milled to form powders with an average diameter of about 800 nm; the powders were dried and mixed with PES resin, potassium titanate whisker, antioxidant 1010, and polyethylene wax according to a weight ratio of about 10: 100: 30: 0.2: 0.1 in a high speed mixer to prepare a mixture; then the mixture was extruded and granulated, then injection molded to form a substrate.

In step c), the substrate was immersed in a chemical copper plating solution for about 3 h to form a copper layer with a thickness of about 5 m; then the substrate was immersed in a chemical nickel plating solution for about 10 min to form a nickel layer with a thickness of about 3 m on the copper layer, thus forming the plastic article as a shell for an electronic connector.

Embodiment 4

The method in Embodiment 4 is substantially similar to that in Embodiment 1 , with the exception of the following respects.

In step a), CUM00 _. 5O2 _. 5 was ball milled to form powders with an average diameter of about 900 nm; the powders were dried and mixed with PC resin, antioxidant 1076, and polyethylene wax according to a weight ratio of about 10: 100: 0.2: 0.1 in a high speed mixer to prepare a mixture; then the mixture was extruded and granulated, then blow molded to form a substrate.

In step c), the substrate was immersed in a chemical nickel plating solution for about 10 min to form a first nickel layer with a thickness of about 3 m; then the substrate was immersed in a chemical copper plating solution for about 2 h to form a copper layer with a thickness of about 6 Mm on the first nickel layer; finally the substrate was again immersed in a chemical nickel plating solution for about 12 min to form a second nickel layer with a thickness of about 4 Mm on the copper layer; thus forming the plastic article as a shell for an electronic part of an automobile. Embodiment 5

The method in Embodiment 5 is substantially similar to that in Embodiment 1 , with the exception of the following respects.

In step a), CuNio.5Bo.5O2 5 was ball milled to form powders with an average diameter of about 900 nm; the powders were dried and mixed with PPO resin, calcium silicate fiber, antioxidant 1076, and polyethylene wax according to a weight ratio of about 10: 100: 10: 0.2: 0.1 in a high speed mixer to prepare a mixture; then the mixture was extruded and granulated by a twin screw extruder, then injection molded to form a substrate.

In step c), the substrate was immersed in a chemical nickel plating solution for about 8 min to form a first nickel layer with a thickness of about 2 m; thereafter the substrate was immersed in a chemical copper plating solution for about 4 h to form a copper layer with a thickness of about 15 m on the first nickel layer; then the substrate was again immersed in the chemical nickel plating solution for about 10 min to form a second nickel layer with a thickness of about 3 m on the copper layer; finally the substrate was flash plated with an aurum layer with a thickness of about 0.03 Mm on the second nickel layer; thus forming the plastic article as a shell for an outdoor connector of a solar cell.

Embodiment 6

A method for preparing a plastic article comprises the following steps.

a) About 58 g of CuO, about 34 g of Ga ₂ O3 and about 14 g of Β ₂ Οβ powders were mixed uniformly; the powders were ball milled in distilled water in a high speed ball grinder for about 12 h to form a first mixture; then the first mixture was dried and calcined at a temperature of about 1000 ^° C for about 2 h to form particles; the particles were ball milled at a high speed until the average diameter of the particles reached up to about

900 nm; and the particles were tested by X-ray diffraction (XRD) and ICP-AES to obtain a composition of CuGao.5Bo.5Oz5.

b) PPS resin, CuGao.5Bo.5O25 particles, antioxidant 1076 and polyethylene wax were mixed according to a weight ratio of about 100: 10: 0.2: 0.1 to form a second mixture; then the second mixture was extruded and granulated, then injection molded to form a substrate.

c) A metal circuit pattern was curved on the substrate by a method substantially similar to that in step b) of Embodiment 1 .

d) The substrate was immersed in a chemical copper plating solution for about 3 h to form a copper layer with a thickness of about 12 μιτι; then the substrate was immersed in a chemical nickel plating solution for about 10 min to form a nickel layer with a thickness of about 3 m on the first copper layer; thus forming the plastic article as a shell for an electric connector.

Embodiment 7

A method for preparing a plastic article comprises the following steps.

a) About 36 g of CuO and about 65 g of M0O ₃ powders were mixed uniformly; the powders were ball milled in distilled water in a high speed ball grinder for about 12 h to form a first mixture; the first mixture was dried and calcined at a temperature of about 800 ^° C for about 2 h to from particles; the particles were ball milled until the average diameter reached up to about 900 nm; and the particles were tested by XRD to obtain a composition of CuMo0 ₄ .

b) PA6T resin, CuMo0 ₄ , antioxidant 1076 and polyethylene wax were mixed according to a weight ratio of about 100: 10: 0.2: 0.1 to form a second mixture; then the second mixture was extruded and granulated, then injection molded to form a substrate. c) A metal circuit pattern was curved on the substrate by a method substantially similar to that in step b) of Embodiment 1 .

d) The substrate was immersed in a chemical nickel plating solution for about 8 min to form a first nickel layer with a thickness of about 2 m; thereafter the substrate was immersed in a chemical copper plating solution for about 4 h min to form a copper layer with a thickness of about 15 m on the first nickel layer; then the substrate was immersed in a chemical nickel plating solution for about 10 min to form a second nickel layer with a thickness of about 3 Mm on the copper layer; finally the substrate was flash plated with an aurum layer with a thickness of about 0.03 Mm on the second nickel layer; thus forming the plastic article as a shell for an outdoor connector of an automobile.

Although explanatory embodiments have been shown and described, it would be appreciated by those skilled in the art that changes, alternatives, and modifications all falling into the scope of the claims and their equivalents may be made in the embodiments without departing from spirit and principles of the present disclosure.