WO2012130059A1

WO2012130059A1 - Shell with brightness gradient effect and method of preparing the same

Info

Publication number: WO2012130059A1
Application number: PCT/CN2012/072541
Authority: WO
Inventors: Yu Fu; Xinying LUN
Original assignee: Shenzhen Byd Auto R&D Company Limited; Byd Company Limited
Priority date: 2011-03-25
Filing date: 2012-03-19
Publication date: 2012-10-04
Also published as: CN102695390B; CN102695390A

Abstract

A shell with brightness gradient effect and a method of preparing the same are provided. The shell comprises: a substrate (1) defining a first surface and a second surface; and a metal coating (2) disposed on the first surface of the substrate (1) and having a protrusion, a cross section of the protrusion having a parabolic top, and a light transmittance of the thickest portion of the protrusion being about 50% or more smaller than that of the thinnest portion of the protrusion.

Description

SHELL WITH BRIGHTNESS GRADIENT EFFECT AND METHOD OF PREPARING

THE SAME

CROSS-REFERENCE TO RELATED APPLICATION

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

201110073857.2, filed with State Intellectual Property Office, P. R. C. on March 25, 2011, the entire content of which is incorporated herein by reference.

FIELD

The present disclosure relates to shells of electronic products, more particularly to a shell with brightness gradient effect and a method of preparing the same.

BACKGROUND

With the rapid development in electronic research, one electronic product is replaced by another with more and more fast speed. New techniques and skills on the surface decoration of the shell of the electronic product are developed increasingly. Most shells for electronic products are formed by plastics. Coloration and surface decoration of plastics may be performed at the same time of plastic molding. However, the secondary processing, such as various kinds of decorating treatment, is generally applied in order to increase life span and visual effect of the electronic product. Gradient effects of plastic shell are usually formed with different colors by spraying, etc. During the spraying process, an angle between a spray gun and a surface of the shell may be changed, and the thicknesses of coatings on the surface of the shell may be different. In that way, colors of the surface of the shell may exhibit gradient effect. Further, spraying with more than one color may also produce gradient effect on the surface of the shell. In this method, two coatings with different colors or different brightness may be sprayed on the surface of the shell. Due to surface tensions of the coating and the surface of the shell, extra coatings may remain in edges of the shell, thus causing undesirable visual effect of the shell. In addition, the aforementioned method may only form linear gradient effect with different colors, but the brightness gradient effect of the same color may not be obtained. Moreover, the angle between the spray gun and the surface of the shell must be precisely controlled in a certain direction, and the coating may be badly wasted. In the method, the adjustment of gradient interfaces is hard to control, and the consistency of the final product is hard to ensure. SUMMARY

In viewing thereof, Embodiments of the present disclosure seek to solve at least one of the problems existing in the prior art to at least some extent. Accordingly, a shell with brightness gradient effect is provided, in which the brightness gradient effect of a same color may be achieved. Furthermore, a method of preparing the shell may also be provided.

A shell with brightness gradient effect according to embodiment of the present disclosure may comprise: a substrate defining a first surface and a second surface; and a metal coating disposed on the first surface of the substrate and having a protrusion, a cross section of the protrusion having a parabolic top, and a light transmittance of the thickest portion of the protrusion being about 50% or more smaller than that of the thinnest portion of the protrusion.

A method of preparing the abovementioned shell may comprise the steps of: 1) pre -treating a substrate to clean first and second surfaces of the substrate; 2) mounting the substrate within a plating fixture having an opening, with a gap of about 5 mm to about 20 mm between the opening and the first surface of the substrate, and then disposing the plating fixture in a plating room to plate a metal coating having a protrusion onto the first surface of the substrate, a cross section of the protrusion having a parabolic top, and a light transmittance of the thickest portion of the protrusion being about 50% or more smaller than that of the thinnest portion of the protrusion.

According to embodiments of the present disclosure, the shell with brightness gradient effect may comprise a substrate and a metal coating disposed on the substrate, the metal coating may have a protrusion, and a cross section of the protrusion may have a parabolic top, and a light transmittance of the thickest portion of the protrusion is about 50% or more smaller than that of the thinnest portion of the protrusion, thus providing the shell with natural brightness gradient effect of the same color. The final products made by the method of preparing the shell with brightness gradient effect according to embodiments of the present disclosure may have good consistency.

While the shells and methods will be described in connection with various preferred illustrative embodiments, it will be understood that it is not intended to limit the shells and methods thereof to those embodiment. On the contrary, it is intended to cover all alternatives, modifications, equivalents as may be included within the spirit and scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages of the present disclosure will become apparent and more readily appreciated from the following description taken in conjunction with the drawings in which:

Fig. 1 is a cross-sectional view of a shell according to an embodiment of the present disclosure;

Fig. 2 is a cross-sectional view of a shell according to another embodiment of the present disclosure; and

Fig. 3 is a cross-sectional view of a plating fixture in a sputtering process according to an embodiment of the present disclosure.

DETAILED DESCRIPTION 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 numbers throughout the descriptions.

Embodiment 1

According to an embodiment of the present disclosure, a shell with brightness gradient effect is provided. Referring to Fig. 1, a cross section of the shell is shown. The shell comprises a substrate 1 and a metal coating 2. The substrate 1 has a first surface and a second surface, and the metal coating 2 is disposed on the first surface of the substrate 1. The metal coating 2 has at least one protrusion, and the number of the protrusions may be determined according to the requirements of different customers. A cross section of the metal coating 2 has a parabolic top, in other words, the cross section of the top surface of protrusion is parabolic. As shown in Fig. 1, the thickest portion of the protrusion is denoted by a point B, and the thinnest portion of the protrusion is denoted by a point A. A light transmittance of the thickest portion B of the protrusion may be about 25%, and a light transmittance of the thinnest portion A of the protrusion may be about 76%. Here, the surface of the substrate on which the metal coating 2 is formed is referred as the first surface, and the surface of the substrate 1 opposite to the first surface of the substrate 1 is referred as the second surface. The light transmittance described above is a parameter for evaluating the light transmission property of a material. Light transmittance is the ratio of a luminous flux transmitting through a sample to a luminous flux transmitted onto the sample. In this embodiment, the metal coating 2 has a nano-level thickness, and it may be difficult to measure the thicknesses of the metal coating 2 by a conventional method. In the prior art, light transmittance is generally used to represent the thickness of the metal coating 2. The higher the light transmittance, the smaller the thickness of the metal coating 2 is; and the lower the light transmittance, the larger the thickness of the metal coating 2 is.

In an embodiment, the substrate 1 may have certain mechanical strength and good light transmittance. The light transmittance of the substrate 1 may be higher than about 70%. The higher the light transmittance, the better the brightness gradient effect is. The substrate 1 may have a surface finish above SPI B2. The higher the surface finish, the better the brightness gradient effect is. The substrate 1 may be formed by injection molding materials having high light transmittance, such as transparent polycarbonate (PC) or transparent polymethyl methacrylate (PMMA). In another embodiment, the substrate 1 may be formed with a transparent primer coating by spraying method to further improve the performance of the substrate 1 , for example, the pores in the surface of the substrate 1 may be filled by the primer coating so as to increase an adhesion between the substrate 1 and the metal coating 2, as long as the substrate 1 formed with the primer coating has a light transmittance higher than about 70%.

In an embodiment, the metal coating 2 may be formed onto the first surface of the substrate 1 by sputtering or vacuum evaporation method. It is required that the metal coating 2 has a good adhesion to the substrate 1. The metal coating 2 may have a protrusion, and a cross section of protrusion may have a smooth parabolic top, in other words, the protrusion has a smooth and parabolic cross section here. The light transmittance of the thickest portion of the protrusion may be about 50% or more smaller than that of the thinnest portion of the protrusion, in other words, the difference obtained by subtracting the light transmittance of the thickest portion of the protrusion from the light transmittance of the thinnest portion of the protrusion is not less than about 50%. The metal coating 2 may be formed by sputtering In-Sn alloy or Al. Because the cross section of the protrusion has a smooth parabolic top, change in the thickness of the metal coating 2 is smooth, thus achieving natural brightness gradient effect.

In an embodiment, the shell may further comprise a middle paint layer 3 disposed onto a surface of the metal coating 2. The middle paint layer 3 may be used to adjust color and enhance contrast with the metal coating 2, for example, the middle paint layer 3 may be adhered to the metal coating 2. In an embodiment, the middle paint layer 3 may have a darker color to further improve the brightness gradient effect. The middle paint layer 3 may have a light transmittance lower than about 10%, and a thickness ranging from about 5 μιη to about 10 μιη. In an embodiment, the middle paint layer 3 may be made by a black color paste which has a large contrast with the metal coating 2. In that way, the gradient effect may be ensured, and some structures such as fasteners located at edges of the shell having a disadvantageous influence on the appearance of the shell may be covered. Furthermore, the color of the middle paint layer 3 may be adjusted, for example, the middle paint layer 3 may be made from a color paste (paint) such as Cashew VM 9000 or PPG XPB67381VS.

In an embodiment, the shell may further comprise a finish paint layer 4 disposed onto the second surface of the substrate 1. The finish paint layer 4 may protect the shell and improve the brightness of the shell. The finish paint layer 4 may have a thickness ranging from about 10 μιη to about 20 um. The finish paint layer 4 may have a light transmittance higher than about 80%. The finish paint layer 4 may be made from a color paste (paint) such as Cashew VM 7302 or PPG R66051. The finish paint layer 4 may have a good abrasion resistance and a good adhesion with the substrate 1.

In Embodiment 1, the shell comprises the middle paint layer 3 and the finish paint layer 4. However, it would be appreciated that in other embodiments, the shell may be with the middle paint layer 3 or the finish paint layer 4, alternatively the shell may be without the middle paint layer 3 and the finish paint layer 4.

The shell with brightness gradient effect described above may be prepared by a process comprising the following steps.

1) A substrate was provided and pre-treated.

A material with high light transmittance, such as transparent PC or PMMA, was injection molded to prepare the substrate. First and second surfaces of the substrate were cleaned with alcohol or n-heptane to remove dirts, such as dirt pits, broken filaments or greasy dirts, thus providing the substrate with clean surfaces.

2) A metal coating was plated.

A plating fixture having an opening in the centre of a top surface thereof was provided. A diameter of the opening was about 30 mm. The substrate was placed within the plating fixture, and a gap between the first surface of the substrate and the opening was about 5 mm. The plating fixture was placed in a horizontal sputtering production line in a plating room, and then the substrate was plated with an In-Sn alloy coating under a power of about 3 kW for about 2 seconds to plate a metal coating having a protrusion onto the first surface of the substrate. Because the metal coating was formed onto the substrate by sputtering, the problem of poor control on the gradient effect in a spraying process may be avoided.

The method further comprises a step 3).

3) A middle paint layer was sprayed.

The substrate having the metal coating was mounted to a spraying fixture, and the spraying fixture was mounted to a spraying production line. Then, the substrate was sprayed with the middle paint of Cashew VM 9000, which has a black color and a viscosity of about 7.8±0.1 s. The middle paint layer has a thickness ranging from about 8 μιη to about 10 μιη. The middle paint was subjected to leveling at about 55°C for about 10 min, then cured in an IR furnace at a temperature of about 75°C for about 20 min to form the middle paint layer on the metal coating.

The method may further comprise a step 4).

4) A finish paint layer was sprayed.

The substrate formed with the middle paint layer was mounted to a spraying fixture, and the spraying fixture was mounted to a spraying production line. Then, the second surface of the substrate was sprayed with the finish paint of Cashew VM 7302 having a viscosity of about 8.2±0.2 s at a linear velocity of about 3 m/min. The finish paint layer has a thickness of about 12±2 μιη. The finish paint was subjected to leveling at about 60°C for about 10 min, then cured in a UV furnace under a powder of about 1500±100 mJ/cm² to form the finish paint layer on the second surface of the substrate.

Embodiment 2

Referring to Fig. 2, a cross section of a shell with brightness gradient effect is shown. The shell comprises a substrate 10 and a metal coating 20. The substrate 10 has a first surface and a second surface, and the metal coating 20 is disposed onto the first surface of the substrate 10. The metal coating 20 has at least one protrusion. A cross section of the protrusion has a parabolic top, and the number of protrusions may be adjusted according to the requirements of different customers. In this embodiment, the thickest portion of the protrusion is denoted by a point D, and the thinnest portion of the protrusion is denoted by a point C. A light transmittance of the thickest point D of the protrusion may be about 5%, and a light transmittance of the thinnest portion B of the protrusion may be about 80%. Here, the surface of the substrate on which the metal coating 20 is formed is referred as the first surface, and the surface of the substrate 10 opposite to the first surface of the substrate 1 is referred as the second surface.

In an embodiment, the substrate 10 may have certain mechanical strength and be without injection molding defects such as shrinkages or flow marks. The substrate 10 may have a light transmittance lower than 10%. The substrate 10 may be made from a material selected from the group consisting of: transparent polycarbonate (PC), transparent polymethyl methacrylate (PMMA), acrylonitrile-butadiene-styrene (ABS), and combinations thereof. In an embodiment, if the substrate 10 has a light transmittance higher than about 10%, an opaque primer coating may be sprayed onto the substrate 10 to casue the substrate 10 have a light transmittance lower than about 10%.

In an embodiment, the metal coating 20 may be formed onto the substrate 10 by sputtering or vacuum evaporation method. It is required that the metal coating 20 has a good adhesion to the substrate 10. The metal coating 20 may have a protrusion, and a cross section of protrusion may have a smooth parabolic top, in other words, the protrusion has a smooth and parabolic cross section here. The light transmittance of the thickest portion of the protrusion may be about 50% or more smaller than that of the thinnest portion of the protrusion, in other words, the difference obtained by subtracting the light transmittance of the thickest portion of the protrusion from the light transmittance of the thinnest portion of the protrusion is not less than about 50%. The metal coating 2 may be formed by sputtering a material such as In-Sn alloy or Al. Because the cross section of the protrusion has a smooth parabolic top, change in the thickness of the metal coating 2 is smooth, thus achieving natural brightness gradient effect.

In an embodiment, the shell may further comprise a middle paint layer 30 disposed onto a surface of the metal coating 20 for adjusting color. The middle paint layer 30 may be made from a material having high light transmittance and color pastes having corresponding colors. The addition of color pastes may ensure brightness gradient effect, and provide corresponding colors to the coatings. The middle paint layer 30 may have a light transmittance higher than about 80%, and a thickness ranging from about 5 μιη to about 10 μιη. In an embodiment, the middle paint layer 30 may have no appearance defects such as impurities or broken filaments. In an embodiment, the middle paint layer 30 may be made from Cashew VM 9000 or PPG XPB67381VS.

In an embodiment, the shell may further comprise a finish paint layer 40 disposed onto a surface of the middle paint layer 30. The finish paint layer 40 may protect the shell and enhance the brightness of the shell. In another embodiment, the finish paint layer 40 may also be directly formed onto the surface of the metal coating 20 for the shell with no color adjusting requirements. The finish paint layer 40 may have a thickness ranging from about 10 μιη to about 20 μιη. The finish paint layer 40 may be made from a material having a light transmittance higher than about 80%, such as Cashew VM 7302 or PPG R66051. In an embodiment, the finish paint layer 40 may have a good adhesion with the metal coating 20 or the middle paint layer 30, a good abrasion resistance, and be without appearance defects such as impurities or greasy dirts.

In Embodiment 2, the shell comprises the middle paint layer 30 and the finish paint layer 40. However, it would be appreciated that in other embodiments, the shell may have the middle paint layer 30 or the finish paint layer 40, alternatively, the shell may have none of the middle paint layer 30 and the finish paint layer 40.

A method of preparing the abovementioned shell with brightness gradient effect is provided.

The method comprises the following steps.

1) A substrate was provided and pre-treated.

A material with high light transmittance, such as transparent PC or PMMA, was injection molded to form a substrate. First and second surfaces of the substrate were cleaned with alcohol or n-heptane to remove the dirts, such as dirt pits, broken filaments or greasy dirts, thus providing the substrate with clean surfaces.

2) A metal coating was plated.

A plating fixture having an opening was provided, and the opening had a diameter of about 30mm. The substrate was place within the plating fixture, and a gap between the first surface of the substrate and the opening was about 20 mm. The plating fixture was placed in a horizontal sputtering line, and the substrate was plated with Al under a power of about 8 kW for about 4 seconds to plate a Al coating having a protrusion onto the first surface of the substrate. Because the metal coating was disposed on the substrate by sputtering, the problem of poor control on the gradient effect in a spraying process may be avoided. Then, the step 2) was performed at least three times. The light transmittance of the metal coating was measured by a light transmittance measurement instrument. The method may further comprise a step 3).

3) A middle paint layer was sprayed.

The substrate having the Al coating was mounted to a spraying fixture. The spraying fixture was placed onto a spraying production line, and the substrate was sprayed with a PPG XPB67381VS coating having a viscosity ranging from about 8 s to about 8.5 s at a linear velocity of about 6 m/min. The PPG XPB67381VS coating layer had a thickness ranging from about 8 μιη to about 15 μιη, and was subjected to leveling at a temperature of about 50°C for about 10 min. Then, the PPG XPB67381VS coating layer was cured in an IR furnace at a temperature of about 60°C for about 30 min to form the middle paint layer on the metal coating.

The method may still further comprise a step 4).

4) A finish paint layer was sprayed.

The substrate formed with the middle paint layer was mounted to a spraying fixture, and the spraying fixture was placed onto the spraying production line. The substrate was sprayed with a paint of PPG R66051 having a viscosity ranging from about 8 s to about 9 s at a linear velocity of about 6 m/min. The PPG R66051 coating layer had a thickness ranging from about 8 μιη to about 15 μιη, and then was subjected to leveling at a temperature of about 60°C for about 10 min. Finally, the PPG R66051 coating layer was cured in a UV furnace under a power of about 600-1200mJ/cm² to form the finish paint layer on the middle paint layer.

Referring to Fig. 3, a cross section of the plating fixture 100 is shown. The plating fixture 100 is a hollow box having an opening 101 in a top surface thereof. Metal particles 300 for forming the metal coating may pass through the opening 101 and reach the substrate 200 placed on a bottom of the plating fixture 100. Size and gradient shape of the metal coating may be adjusted by controlling shape and size of the opening 101. An area of the substrate 200 to be plated is aligned with the opening 101 in the fixture plating 100, and the substrate 200 is fixed. Size and gradient level of the metal coating may be adjusted by controlling a distance H between the opening 101 and the surface of the substrate 200. Because of linear movement of the metal particles 300, an area of the substrate facing directly toward the opening 101 may be adhered with more metal particles, and for one area other than the area facing directly toward the opening 101, the larger the distance from the one area to the area facing directly toward the opening 101, the less metal particles are. In this way, a protrusion may be formed by the metal coating 200, and a cross section of the protrusion may have a parabolic top. The protrusion may have a thicker portion at the center thereof which has a smaller light transmittance, and a thinner portion at edges thereof which has a larger light transmittance, thus achieving brightness gradient effect. In an embodiment, if a middle paint layer was sprayed or printed onto the metal coating to adjust color, then brightness gradient effect of the same color may be achieved. The larger the distance H between the opening 101 and the surface of the substrate 200, the more natural the brightness gradient effect is. The distance H between the opening 101 and the surface of the substrate 200 may range from about 5 mm to about 20 mm to ensure natural brightness gradient effect of the final product. If the distance H between the opening 101 and the surface of the substrate 200 is larger than about 20 mm, plating may not be performed due to too large distance H between the substrate 200 and the opening 101. In an embodiment, the metal coating plating may be performed for at least one times to overlap the metal coatings in order to ensure more natural brightness gradient effect. During the preparing process of the shell, the brightness gradient effect of the shell may be adjusted by changing the distance between the plating fixture 100 and the substrate 200, and the problem of adjusting an angle between a spray gun and a surface of a substrate in a spraying process may be avoided. Therefore, the final products may have good consistency. Because the metal coating is formed by metal particles plated onto the surface of the substrate and the thickness of the metal coating is very small, a problem of extra coating during the spraying may be avoided.

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

Claims

What is claimed is:

1. A shell with brightness gradient effect, comprising:

a substrate defining a first surface and a second surface; and

a metal coating disposed on the first surface of the substrate and having a protrusion, a cross section of the protrusion having a parabolic top, and a light transmittance of the thickest portion of the protrusion being about 50% or more smaller than that of the thinnest portion of the protrusion.

2. The shell according to claim 1, wherein a light transmittance of the substrate is smaller than about 10%; wherein the shell further comprises a middle paint layer disposed on the metal coating for adjusting color; wherein a light transmittance of the middle paint layer is greater than about 80%; and wherein the middle paint layer has a thickness ranging from about 5 μιη to about 10 μιη.

3. The shell according to claim 1, wherein a light transmittance of the substrate is greater than about 70%; wherein the shell further comprises a middle paint layer disposed on the metal coating for adjusting color and improving contrast; wherein a light transmittance of the middle paint layer is smaller than about 10%; and wherein the middle paint layer has a thickness ranging from about 5 μιη to about 10 μιη.

4. The shell according to claim 2, further comprising a first finish paint layer disposed on the middle paint layer; wherein a light transmittance of the first finish paint layer is greater than about 80% and a thickness of the first finish paint layer ranges from about 10 μιη to about 20 μιη.

5. The shell according to claim 3, further comprising a second finish paint layer disposed on a second surface of the substrate; wherein a light transmittance of the second finish paint layer is greater than about 80% and a thickness of the second finish paint layer ranges from about 10 μιη to about 20 μιη.

6. The shell according to claim 1, wherein a light transmittance of the substrate is smaller than about 10%; wherein the shell further comprises a first finish paint layer disposed on the metal coating; a light transmittance of the first finish paint layer is greater than about 80% and a thickness of the first finish paint layer ranges from about 10 um to about 20 μιη.

7. A method of preparing a shell with brightness gradient effect, comprising the steps of:

1) pre-treating a substrate to clean first and second surfaces of the substrate;

2) mounting the substrate within a plating fixture having an opening, with a gap of about 5 mm to about 20 mm between the opening and the first surface of the substrate, and then disposing the plating fixture in a plating room to plate a metal coating having a protrusion onto the first surface of the substrate, a cross section of the protrusion having a parabolic top, and a light transmittance of the thickest portion of the protrusion being about 50% or more smaller than that of the thinnest portion of the protrusion.

8. The method according to claim 7, further comprising:

3) mounting the substrate having the metal coating to a spraying fixture, mounting the spraying fixture to a spraying production line, spraying a middle paint onto the metal coating, then curing the middle paint to form a middle paint layer on the metal coating.

9. The method according to claim 7 or 8, further comprising:

4) mounting the substrate to a spraying fixture, mounting the spraying fixture to a spraying production line, spraying a finish paint onto the second surface of the substrate and/ or onto the metal coating or the middle paint layer, then curing the finish paint to form a finish paint layer on the second surface of the substrate and/or on the metal coating or the middle paint layer.

10. The method according to claim 7, wherein the step 2) is performed at least one times.