WO2022006854A1

WO2022006854A1 - Covers for electronic devices

Info

Publication number: WO2022006854A1
Application number: PCT/CN2020/101345
Authority: WO
Inventors: Kuan-Ting Wu; Yong-jun LI; Chi Hao Chang; Ya-Ting Yeh
Original assignee: Hewlett-Packard Development Company, L.P.
Priority date: 2020-07-10
Filing date: 2020-07-10
Publication date: 2022-01-13
Also published as: TW202202583A

Abstract

Covers for electronic devices, electronic devices, and methods for making the covers. In one example, described herein is a cover for an electronic device comprising: a substrate; a waterborne primer coating layer on a surface of the substrate; a waterborne base coating layer on the primer coating layer; and a top coating layer on the waterborne base coating layer, wherein the top coating layer comprises a waterborne UV topcoat and/or a UV topcoat.

Description

COVERS FOR ELECTRONIC DEVICES

BACKGROUND

The use of personal electronic devices of all types continues to increase. Cellular phones, including smartphones, have become nearly ubiquitous. Tablet computers have also become widely used in recent years. Portable laptop computers continue to be used by many for personal, entertainment, and business purposes. For portable electronic devices in particular, much effort has been expended to make these devices more useful and more powerful while at the same time making the devices smaller, lighter, and more durable. The aesthetic design of personal electronic devices is also of concern in this competitive market. Devices such as mobile phones, tablets and portable computers are generally provided with a casing. The casing typically provides a number of functional features, e.g., protecting the device from damage.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a cross-sectional view illustrating an example cover for an electronic device in accordance with examples of the present disclosure;

FIG. 2 is a cross-sectional view illustrating another example cover for an electronic device in accordance with examples of the present disclosure;

FIG. 3 is a cross-sectional view illustrating a further example cover for an electronic device in accordance with examples of the present disclosure;

FIG. 4 is a cross-sectional view illustrating a still further example cover for an electronic device in accordance with examples of the present disclosure;

FIG. 5 is a cross-sectional view illustrating another example cover for an electronic device in accordance with examples of the present disclosure;

FIG. 6 is a flowchart illustrating an example method of making a cover for an electronic device in accordance with examples of the present disclosure; and

FIG. 7 is a flowchart illustrating another example method of making a cover for an electronic device in accordance with examples of the present disclosure.

DETAILED DESCRIPTION

Electronic devices can have covers or casings with various surface properties such as an anti-smudging or anti-fingerprints. These surface properties can usually be obtained by coatings that are based in organic solvents. However, use of solvents is of increasing concerns due to harmful effects on the health and safety of workers and also the negative impact on the environment. Thus, there is an increasing need to use waterborne coatings to achieve various surface properties.

This disclosure describes an anti-fingerprint waterborne ultra-violet (UV) coating solution to not only obtain an anti-fingerprint surface finish but to also obtain a pencil hardness of from about 3H to about 5H while reducing or eliminating organic solvent use.

In some examples, described herein is a cover for an electronic device comprising: a substrate; a waterborne primer coating layer on a surface of the substrate; a waterborne base coating layer on the primer coating layer; and a top coating layer on the waterborne base coating layer, wherein the top coating layer comprises a waterborne UV topcoat and/or a UV topcoat, wherein the waterborne UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof, and (iii) water in an amount of from about 5 wt%to about 15 wt%based on the total weight of the waterborne UV topcoat, and wherein the UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof, and (iii) at least one organic solvent.

In some examples, the substrate comprises plastic, carbon fiber, composite material, a metal, or combinations thereof.

In some examples, the metal comprises aluminum and aluminum alloys, titanium and titanium alloys, stainless steel, magnesium and magnesium alloys, aluminum and aluminum alloys, lithium and lithium alloys, and combinations thereof.

In some examples, the waterborne primer coating layer has a thickness of from about 10 μm to about 30 μm.

In some examples, the waterborne base coating layer has a thickness of from about 10 μm to about 25 μm.

In some examples, the top coating layer has a thickness of from about 15 μm to about 25 μm.

In some examples, described herein is an electronic device comprising: an electronic component; and a cover enclosing the electronic component, the cover comprising: a metal substrate; a micro-arc oxidation layer or a passivation layer on at least one surface of the metal substrate; an optional powder coating layer on the passivation layer; a waterborne primer coating layer on the micro-arc oxidation layer or the passivation layer or the optional powder coating layer; a waterborne base coating layer on the primer coating layer; and a top coating layer on the waterborne base coating layer, wherein the top coating layer comprises a waterborne UV topcoat and/or a UV topcoat, wherein the waterborne UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof, and (iii) water in an amount of from about 5 wt%to about 15 wt%based on the total weight of the waterborne UV topcoat, and wherein the UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof, and (iii) at least one organic solvent.

In some examples, the electronic device is a laptop, a desktop computer, a keyboard, a mouse, a smartphone, a tablet, a monitor, a television screen, a speaker, a game console, a video player, an audio player, or a combination thereof.

In some examples, the powder coating layer is not optional.

In some examples, the passivation coating layer has a thickness of from about 1 μm to about 5 μm.

In some examples, the micro-arc oxidation layer has a thickness of from about 2 μm to about 15 μm.

In some examples, described herein is a method of making a cover for an electronic device comprising: forming a micro-arc oxidation layer or a passivation layer on at least one surface of a metal substrate; applying an optional powder coating layer on the passivation layer; applying a waterborne primer coating layer on the micro-arc oxidation layer or the passivation layer or the optional powder coating layer; applying a waterborne base coating layer on the primer coating layer; and applying a top coating layer on the waterborne base coating layer, wherein the top coating layer comprises a waterborne UV topcoat and/or a UV topcoat, wherein the waterborne UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof, and (iii) water in an amount of from about 5 wt%to about 15 wt%based on the total weight of the waterborne UV topcoat, and wherein the UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof, and (iii) at least one organic solvent.

In some examples, the passivation coating layer has a thickness of from about 1 μm to about 5 μm; and the micro-arc oxidation layer has a thickness of from about 2 μm to about 15 μm.

It is noted that when discussing the cover, the electronic device, or the method of manufacturing the cover, such discussions of one example are to be considered applicable to the other examples, whether or not they are explicitly discussed in the context of that example. Thus, in discussing a metal alloy in the context of the cover, such disclosure is also relevant to and directly supported in the context of the electronic device, the method of manufacturing the multi-color electronic housing, and vice versa.

Covers for Electronic Devices

The present disclosure describes covers for electronic devices that can be strong and lightweight and have a decorative appearance. The cover can provide an enclosure for an electronic device and the enclosure can include a substrate. The substrate can comprise a metal. The metals used for the substrate may be a light metal. The term “light metal” refers to metals and alloys that are generally any metal of relatively Iow density including metal that is less than about 5 g/cm ³ in density. In some cases, light metal can be a material including aluminum, magnesium, titanium, lithium, zinc, and alloys thereof. These light metals can have useful properties, such as Iow weight, high strength, and an appealing appearance. However, some of these metals can be easily oxidized at the surface, and may be vulnerable to corrosion or other chemical reactions at the surface. For example, magnesium or magnesium alloys in particular can be used to form covers for electronic devices because of the Iow weight and high strength of magnesium. Magnesium can have a somewhat porous surface that can be vulnerable to chemical reactions and corrosion at the surface. In some examples, magnesium or magnesium alloy can be treated by micro-arc oxidation to form a layer of protective oxide at the surface. With this example in mind, it is understood that magnesium alloy may be described herein as a class of alloys in some detail by way of example for convenience, but it is also understood that other light metal substrates can be freely substituted for the magnesium alloy examples herein with respect to the covers, electronic devices, and methods herein.

Using magnesium or magnesium alloy as an example class of metal substrates that can be used, this material can form a protective oxide layer that can increase the chemical resistance, hardness, and durability of the magnesium or magnesium alloy. However, micro-arc oxidation (MAO) can also create a dull appearance instead of the original luster of the metal. In other examples, as an alternative to the MAO the magnesium or magnesium alloy can be treated using a passivation layer. The passivation layer for the protective coating may be opaque or transparent and may include molybdates, vanadates, phosphates, chromates, stannates, manganese salts, or a combination thereof. The passivation layer may be about 1 μm to about 5 μm thick.

In certain examples, the cover can have a protective coating such as a MAO layer or a passivation layer and a second protective coating such as a paint coating.

FIG. 1 shows an example cover 100 for an electronic device. The cover 100 includes a substrate 110 with a waterborne primer coating layer 120 on at least one surface (typically the top surface) of the substrate 110. Then there is a waterborne base coating layer 130 on top of the waterborne primer coating layer 120. Then there is a top coating layer 140 on the waterborne base coating layer 130. In this example, the top coating layer 140 includes a waterborne UV topcoat. In this example, the substrate 110 comprises plastic, carbon fiber, composite material, a metal, or combinations thereof.

FIG. 2 shows an example cover 200 for an electronic device. The cover 200 includes a substrate 210 with a waterborne primer coating layer 220 on at least one surface (typically the top surface) of the substrate 210. Then there is a waterborne base coating layer 230 on top of the waterborne primer coating layer 220. Then there is a top coating layer 240 on the waterborne base coating layer 230. In this example, the top coating layer 240 includes a UV topcoat. In this example, the substrate 210 comprises plastic, carbon fiber, composite material, a metal, or combinations thereof.

FIG. 3 shows an example cover 300 for an electronic device. The cover 300 includes a substrate 310 with a passivation layer 320 on the bottom surface of the substrate 310 and another passivation layer 320 on the top surface of the substrate 310. Then there is a waterborne primer coating layer 330 on top of the passivation layer 320. Then there is a waterborne base coating layer 340 on top of the waterborne primer coating layer 330. Then finally there is a top coating layer 350 on top of the waterborne base coating layer 340. In this example, the top coating layer 350 includes a waterborne UV topcoat and/or a UV topcoat. In this example, the substrate 310 comprises a metal, wherein the metal comprises aluminum and aluminum alloys, titanium and titanium alloys, stainless steel, magnesium and magnesium alloys, aluminum and aluminum alloys, lithium and lithium alloys, and combinations thereof.

FIG. 4 shows an example cover 400 for an electronic device. The cover 400 includes a substrate 410 with a micro-arc oxidation layer 420 on the bottom surface of the substrate 410 and another micro-arc oxidation layer 420 on the top surface of the substrate 410. Then there is a waterborne primer coating layer 430 on top of the micro-arc oxidation layer 420. Then there is a waterborne base coating layer 440 on top of the waterborne primer coating layer 430. Then finally there is a top coating layer 450 on top of the waterborne base coating layer 440. In this example, the top coating layer 450 includes a waterborne UV topcoat and/or a UV topcoat. In this example, the substrate 410 comprises a metal, wherein the metal comprises aluminum and aluminum alloys, titanium and titanium alloys, stainless steel, magnesium and magnesium alloys, aluminum and aluminum alloys, lithium and lithium alloys, and combinations thereof.

FIG. 5 shows an example cover 500 for an electronic device. The cover 500 includes a substrate 510 with a passivation layer 520 on the bottom surface of the substrate 510 and another passivation layer 520 on the top surface of the substrate 510. Then there is an optional powder coating layer 530 on the passivation layer 520. Next, there is a waterborne primer coating layer 540 on top of the powder coating layer 530. Then there is a waterborne base coating layer 550 on top of the waterborne primer coating layer 540. Then finally there is a top coating layer 560 on top of the waterborne base coating layer 550. In this example, the top coating layer 560 includes a waterborne UV topcoat and/or a UV topcoat. In this example, the substrate 510 comprises a metal, wherein the metal comprises aluminum and aluminum alloys, titanium and titanium alloys, stainless steel, magnesium and magnesium alloys, aluminum and aluminum alloys, lithium and lithium alloys, and combinations thereof.

As used herein, “cover” refers to the exterior shell of an electronic device that includes or is in the form of an enclosure, and a portion thereof (or the structure thereof) includes a substrate. In other words, the cover can be adapted to contain the internal electronic components of the electronic device. The cover can be an integral part of the electronic device. The term “cover” is not meant to refer to the type of removable protective cases that are often purchased separately for an electronic device (especially smartphones and tablets) and placed around the exterior of the electronic device. Covers as described herein can be used on a variety of electronic devices. For example, a laptop, a desktop, a keyboard, a mouse, a printer, a smartphone, a tablet, a monitor, a television, a speaker, a game console, a video player, an audio player, or a combination thereof. In various examples, the light metal substrate for these covers can be formed by molding, casting, machining, bending, working, stamping, or another process.

In one example, a light metal substrate can be milled from a single block of metal. In other examples, the cover can be made from multiple panels. For example, laptop covers sometimes include four separate cover pieces forming the complete cover of the laptop. The four separate pieces of the laptop cover are often designated as cover A (back cover of the monitor portion of the laptop) , cover B (front cover of the monitor portion) , cover C (top cover of the keyboard portion) and cover D (bottom cover of the keyboard portion) . Covers can also be made for smartphones and tablet computers with a single metal piece or multiple metal panels.

As used herein, a layer that is referred to as being “on” a lower layer can be directly applied to the lower layer, or an intervening layer or multiple intervening layers can be located between the layer and the lower layer. Generally, a layer that is “on” a lower layer can be located further from the substrate. Thus, a “higher” layer applied “on” a “lower” layer may be located farther from the substrate and closer to a viewer viewing the cover from the outside.

It is noted that when discussing covers for electronic devices, the electronic devices themselves, or methods of making covers for electronic devices, such discussions can be considered applicable to one another whether or not they are explicitly discussed in the context of that example. Thus, for example, when discussing the metals used in the light metal substrate in the context of one of the example covers, such disclosure is also relevant to and directly supported in the context of the electronic devices and/or methods, and vice versa. It is also understood that terms used herein will take on their ordinary meaning in the relevant technical field unless specified otherwise. In some instances, there are terms defined more specifically throughout or included at the end of the present disclosure, and thus, these terms are supplemented as having a meaning described herein.

Electronic Devices

A variety of electronic devices can be made with the covers described herein. In various examples, such electronic devices can include various electronic components enclosed by the cover. As used herein, “encloses” or “enclosed” when used with respect to the covers enclosing electronic components can include covers completely enclosing the electronic components or partially enclosing the electronic components. Many electronic devices include openings for charging ports, input/output ports, headphone ports, and so on. Accordingly, in some examples the cover can include openings for these purposes. Certain electronic components may be designed to be exposed through an opening in the cover, such as display screens, keyboard keys, buttons, track pads, fingerprint scanners, cameras, and so on. Accordingly, the covers described herein can include openings for these components. Other electronic components may be designed to be completely enclosed, such as motherboards, batteries, sim cards, wireless transceivers, memory storage drives, and so on. Additionally, in some examples a cover can be made up of two or more cover sections, and the cover sections can be assembled together with the electronic components to enclose the electronic components. As used herein, the term “cover” can refer to an individual cover section or panel, or collectively to the cover sections or panels that can be assembled together with electronic components to make the complete electronic device.

In further examples, the electronic device can be a laptop, a desktop, a keyboard, a mouse, a printer, a smartphone, a tablet, a monitor, a television, a speaker, a game console, a video player, an audio player, or a variety of other types of electronic devices.

Methods of Making Covers for Electronic Devices

In some examples, the covers described herein can be made by first forming the substrate. This can be accomplished using a variety of processes, including molding, insert molding, forging, casting, machining, stamping, bending, working, and so on. The substrate can be made from a variety of metals or other materials. In one example, sheet or forge metal is insert molded into the shape of a cover. The metal for the substrate may be aluminum, magnesium, lithium, titanium, and alloys thereof. As mentioned above, in some examples the substrate can be a single piece while in other examples the substrate can include multiple pieces that each makes up a portion of the cover. Additionally, in some examples the substrate can be a composite made up of multiple metals combined, such as having layers of multiple different metals, other materials, or panels or other portions of the substrate being different metals or other materials.

FIG. 7 is a flowchart illustrating an example method 700 of making a cover for an electronic device. The method includes forming a micro-arc oxidation layer or a passivation layer on at least one surface of a metal substrate -710; applying an optional powder coating layer on the passivation layer -720; applying a waterborne primer coating layer on the micro-arc oxidation layer or the passivation layer or the optional powder coating layer -730; applying a waterborne base coating layer on the primer coating layer -740; and applying a top coating layer on the waterborne base coating layer -750, wherein the top coating layer comprises a waterborne UV topcoat and/or a UV topcoat, wherein the waterborne UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or a combination thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, and combinations thereof, and (iii) at least one organic solvent, and wherein the UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or a combination thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, and combinations thereof, and (iii) water in an amount of from about 5 wt%to about 15 wt%based on the total weight of the UV topcoat.

Substrates for Electronic Device Covers

In some examples, the substrate can comprise plastic, carbon fiber, composite material, a metal, or combinations thereof.

In some examples, the substrate can be made from a metal or combination of metals. The substrate may be a single metal, a metallic alloy, a combination of sections made from multiple metals, or in some examples a combination of metal and other materials. In certain examples, the substrate can include metal, a carbon fiber, a plastic, a ceramic, an alloy thereof, or a composite thereof.

The metal for the substrate may be aluminum, magnesium, lithium, titanium, and alloys thereof. Non-limiting examples of elements that can be included in aluminum or magnesium alloys can include aluminum, magnesium, titanium, lithium, niobium, zinc, bismuth, copper, cadmium, iron, thorium, strontium, zirconium, manganese, nickel, lead, silver, chromium, silicon, tin, gadolinium, yttrium, calcium, antimony, cerium, lanthanum, or others.

In some examples, the substrate can include an aluminum magnesium alloy made up of about 0.5%to about 13%magnesium by weight and 87%to 99.5%aluminum by weight. Examples of specific aluminum magnesium alloys can include 1050, 1060, 1199, 2014, 2024, 2219, 3004, 4041, 5005, 5010, 5019, 5024, 5026, 5050, 5052, 5056, 5059, 5083, 5086, 5154, 5182, 5252, 5254, 5356, 5454, 5456, 5457, 5557, 5652, 5657, 5754, 6005, 6005A, 6060, 6061, 6063, 6066, 6070, 6082, 6105, 6162, 6262, 6351, 6463, 7005, 7022, 7068, 7072, 7075, 7079, 7116, 7129, and 7178.

In further examples, the substrate can include magnesium metal, a magnesium alloy that can be about 99 wt%or more magnesium by weight, or a magnesium alloy that is from about 50 wt%to about 99 wt%magnesium by weight. In a particular example, the substrate can include an alloy including magnesium and aluminum. Examples of magnesium-aluminum alloys can include alloys made up of from about 91%to about 99%magnesium by weight and from about 1%to about 9%aluminum by weight, and alloys made up of about 0.5%to about 13%magnesium by weight and 87%to 99.5%aluminum by weight. Specific examples of magnesium-aluminum alloys can include AZ63, AZ81, AZ91, AM50, AM60, AZ31, AZ61, AZ80, AE44, AJ62A, ALZ391, AMCa602, LZ91, and Magnox.

The substrate can be shaped to fit any type of electronic device, including the specific types of electronic devices described herein. In some examples, the substrate can have any thickness suitable for a particular type of electronic device. The thickness of the metal in the substrate can be selected to provide a desired level of strength and weight for the cover of the electronic device. In some examples, the substrate can have a thickness from about 0.5 mm to about 2 cm, from about 1 mm to about 1.5 cm, from about 1.5 mm to about 1.5 cm, from about 2 mm to about 1 cm, from about 3 mm to about 1 cm, from about 4 mm to about 1 cm, or from about 1 mm to about 5 mm, though thicknesses outside of these ranges can be used.

Protective Coatings for Electronic Device Covers

In one example, a protective coating can be applied to the substrate and can be a micro-arc oxidation layer on a surface thereof. Micro-arc oxidation, also known as plasma electrolytic oxidation, is an electrochemical process where the surface of a metal is oxidized using micro-discharges of compounds on the surface of the substrate when immersed in a chemical or electrolytic bath, for example. The electrolytic bath may include predominantly water with about 1 wt%to about 5 wt%electrolytic compound (s) , e.g., alkali metal silicates, alkali metal hydroxide, alkali metal fluorides, alkali metal phosphates, alkali metal aluminates, the like, or a combination thereof. The electrolytic compounds may likewise be included at from about 1.5 wt%to about 3.5 wt%, or from about 2 wt%to about 3 wt%, though these ranges are not considered limiting. In one example, a high-voltage alternating current can be applied to the substrate to create plasma on the surface of the substrate. In this process, the substrate can act as one electrode immersed in the electrolyte solution, and the counter electrode can be any other electrode that is also in contact with the electrolyte. In some examples, the counter electrode can be an inert metal such as stainless steel. In certain examples, the bath holding the electrolyte solution can be conductive and the bath itself can be used as the counter electrode. A high direct current or alternating voltage can be applied to the substrate and the counter electrode. In some examples, the voltage can be about 200 V or higher, such as about 200 V to about 600 V, about 250 V to about 600 V, about 250 V to about 500 V, or about 200 V to about 300 V. Temperatures can be from about 20 ℃ to about 40 ℃, or from about 25 ℃ to about 35 ℃, for example, though temperatures outside of these ranges can be used. This process can oxidize the surface to form an oxide layer from the substrate material. Various metal or metal alloy substrates can be used, including aluminium, titanium, lithium, magnesium, and/or alloys thereof, for example. The oxidation can extend below the surface to form thick layers, as thick as 30 μm or more. In some examples the oxide layer can have a thickness from about 1 μm to about 25 μm, from about 1 μm to about 22 μm, or from about 2 μm to about 20 μm. Thickness can likewise be from about 2 μm to about 15 μm, from about 3 μm to about 10 μm, or from about 4 μm to about 7 μm. The oxide layer can, in some instances, enhance the mechanical, wear, thermal, dielectric, and corrosion properties of the substrate. The electrolyte solution can include a variety of electrolytes, such as a solution of potassium hydroxide. In some examples, the substrate can include a micro-arc oxidation layer on one side, or on both sides.

In an alternative example, the protective coating is an opaque passivation layer. The passivation layer may refer to a layer or coating over the substrate. Passivation may refer to the use of a light coat of a protective material, such as metal oxide, to create a shell against corrosion. Chemicals may be applied to the surface of the substrate to induce the passivation layer. For example, the chemicals may include at least one of molybdates, vanadates, phosphates, chromates, stannates and manganese salts. The passivation layer may have a thickness of 1-5 μm.

In further examples, a passivation treatment can be used to form a transparent passivation layer as the protective coating. It is noted that the transparent passivation layer is described as a layer for convenience, and thus, can be in the form of a layer. However, the term “passivation layer” also includes metal surface treatment of the exposed metal substrate. In some examples, the transparent passivation layer can include a chelating agent and a metal ion or a chelated metal complex thereof, wherein the metal ion is an aluminum ion, an indium ion, a nickel ion, a chromium ion, a tin ion, or a zinc ion. In certain examples, passivation treatment can be applied at a pH from about 2 to about 6. In a particular example, the pH can be about 2.5 to about 3.5. In further examples, the transparent passivation layer can include an oxide of one of these metals. In some cases, various contaminants can be present on the surface of the light metal substrate. The chelating agent can chelate such contaminants and prevent the contaminants from attaching to the surface of the light metal substrate. Non-limiting examples of chelating agents can include ethylenediaminetetraacetic acid, ethylenediamine, nitrilotriacetic acid, diethylenetriaminepenta (methylenephosphonic acid) , nitrilotris (methylenephosphonic acid) and 1-hydroxyethane-1, 1-disphosphonic acid. At the same time, a passivating metal oxide layer may form on the surface of the light metal substrate. In some examples, the transparent passivation layer can have a thickness from about 30 nm to about 3 μm. In certain examples, the transparent passivation layer can be added to the pre-existing surface of the light metal substrate, such that the transparent passivation layer includes additional material added onto the surface of the light metal substrate. In other examples, the passivation layer can involve converting the existing surface of the light metal substrate into a passive layer so that no net addition of material to the pre-existing surface occurs.

Primer Coating, Base Coating, Top Coating Layers

In some examples, housings described and prepared herein can include a coating (or application of coating) , such as by application of a spray coating or electrostatically-applied coating to a surface of the metal. The coating can provide an aesthetic appeal and/or protection to the housing. Spray coating can be used to apply a primer coat, a base coat, a top coat, or a combination thereof. Electrostatic coating can be used to a powder coat. Sprayed coatings can be applied as primer coatings, base coatings, top coatings, etc.

Waterborne Primer Coating Layer

In some examples, the waterborne primer coating layer can comprise from about 10 wt%to about 30 wt%resins, from about 0.3 wt%to about 10 wt%pigments, from about 10 wt%to about 20 wt%co-solvent, from 0.3 wt%to about 3 wt%surfactant, and from about 50 wt%to about 70 wt%pure water.

In some examples, the waterborne primer coating layer resin can comprise polyurethane, silicone-polyurethane copolymer, polyurethane-polystyrene copolymer, polyurethane based copolymers, polyester, epoxy, epoxy-polyester, and combinations thereof. In an example, the waterborne primer coating layer resin is a polyester polyurethane.

A waterborne primer coating layer, for example, can include a polyester, polyurethane, or a combination thereof that can be applied to a surface of the substrate. The waterborne primer coating layer can be cured by baking the surface at a temperature that can range from about 60℃ to about 80℃ for a time period that can range from about 15 minutes to about 40 minutes. The waterborne primer coating layer can be applied at a thickness that can range from about 10 μm to about 30 μm.

In some examples, the waterborne primer coating layer may comprise a pigment including carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, a synthetic pigment, dye, a metallic powder, aluminum oxide, carbon nanotubes (CNTs) , graphene, graphite, an organic powder, or combinations thereof.

The waterborne primer coating layer may have a thickness of less than about 30 μm, or less than about 25 μm, or less than about 20 μm, or less than about 15 μm. The thickness of the waterborne primer coating layer or any other layer described herein can be measured after it has been applying using, for example, a micrometre screw gauge or scanning electron microscope (SEM) .

In some examples the waterborne primer coating layer is thicker than the waterborne base coating layer or the top coating layer.

Waterborne Base Coating Layer

In some examples, the waterborne base coating layer can comprise from about 10 wt%to about 30 wt%resins, from about 0.3 wt%to about 10 wt%pigments, from about 10 wt%to about 20 wt%co-solvent, from 0.3 wt%to about 3 wt%surfactant, and from about 50 wt%to about 70 wt%pure water.

In some examples, the waterborne base coating layer resin can comprise polyacrylic, polyurethane, silicone-polyurethane copolymer, polyurethane-polystyrene copolymer, polyurethane based copolymers, polyester, epoxy, epoxy-polyester, and combinations thereof.

A waterborne base coating layer can comprise pigments including carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, synthetic pigment, metallic powder, aluminum oxide, organic powder, inorganic powder, plastic bead, color pigment, dye, or combinations thereof.

The waterborne base coating layer can be applied at a thickness that can range from about 10 μm to about 25 μm. In some examples, the base coating layer has a thickness of less than about 25 μm, or less than about 20 μm, or less than about 15 μm.

Top Coating Layer

In some examples, the top coating layer comprises a waterborne UV topcoat and/or a UV topcoat. In some examples, the top coating layer can have a thickness of from about 15 μm to about 25 μm.

Waterborne UV Topcoat

The waterborne UV topcoat comprises (i) from about 10 wt%to about 30 wt%of a resin including a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof; (ii) from about 0.1 wt%to about 5 wt%of fluoropolymers and/or silanes including long chain silanes, short chain silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof; (iii) from about 5 wt%to about 40 wt%of pure water; (iv) from about 0 wt%to about 3 wt%of a matting agent such as silica; (v) from 0.1 wt%to about 2 wt%of a surfactant; and (vi) from about 0 wt%to about 10 wt%of pigments.

The waterborne UV topcoat can comprise pigments including carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, synthetic pigment, metallic powder, aluminum oxide, organic powder, inorganic powder, plastic bead, color pigment, dye, or combinations thereof.

The waterborne UV topcoat can be cured at a temperature that can range from about 50℃ to about 60℃ for a time period that can range from about 5 minutes to about 10 minutes. Then the curing can be followed by UV exposure to a light having an energy ranging from about 700 mJ/cm ² to about 1,200 mJ/cm ² for from about 10 seconds to about 30 seconds.

UV Topcoat

The UV topcoat comprises (i) from about 10 wt%to about 30 wt%of a resin including a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof; (ii) from about 0.1 wt%to about 5 wt%of fluoropolymers and/or silanes including long chain silanes, short chain silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof; (iii) from about 5 wt%to about 20 wt%of an organic solvent; (iv) from about 0 wt%to about 3 wt%of a matting agent such as silica; (v) from 0.1 wt%to about 2 wt%of a surfactant; and (vi) from about 0 wt%to about 10 wt%of pigments.

The UV topcoat can comprise pigments including carbon black, titanium dioxide, clay, mica, talc, barium sulfate, calcium carbonate, synthetic pigment, metallic powder, aluminum oxide, organic powder, inorganic powder, plastic bead, color pigment, dye, or combinations thereof.

The UV topcoat can be cured at a temperature that can range from about 50℃ to about 60℃ for a time period that can range from about 5 minutes to about 10 minutes. Then the curing can be followed by UV exposure to a light having an energy ranging from about 700 mJ/cm ² to about 1, 200 mJ/cm ² for from about 10 seconds to about 30 seconds.

Powder Coating Layer

In some examples, an optional powder coat sandwiched between a passivation layer and a waterborne primer coating layer can include an epoxy, polyvinyl chloride, polyamides, polyesters, polyurethanes, acrylics, polyphenylene ether, or the like. The powder coat can be electrostatically applied to a surface of the metal substrate. In some examples applying a powder coat can include curing the surface of the metal substrate at a temperature ranging from about 120℃ to about 190℃. The powder coat can be applied at a thickness that can range from about 5 μm to about 15 μm.

Prophetic Examples

The following illustrates examples of the present disclosure. However, it is to be understood that the following is illustrative of the application of the principles of the present disclosure. Numerous modifications and alternative compositions, methods, and systems may be devised without departing from the spirit and scope of the present disclosure. The appended claims are intended to cover such modifications and arrangements.

FIG. 6 is a flowchart illustrating an example method 600 of making a cover for an electronic device. In this example, the substrate comprises a metal, wherein the metal comprises aluminum and aluminum alloys, titanium and titanium alloys, stainless steel, magnesium and magnesium alloys, aluminum and aluminum alloys, lithium and lithium alloys, and combinations thereof. The method includes:

- CNC/forging/thixomolding a magnesium alloy substrate -610;

- forming a micro-arc oxidation layer or a passivation layer on the surface of the magnesium alloy substrate -620;

- next applying a waterborne primer coating layer at a temperature of from about 80℃ to about 120℃ for from about 3 minutes to about 40 minutes -630;

- applying a waterborne base coating layer on the waterborne primer coating layer at a temperature of from about 80℃ to about 120℃ for from about 3 minutes to about 40 minutes -650; applying a top coating layer -660;

- drying the top coating layer: when the top coating layer is a UV topcoat then at a temperature of from about 50℃ to about 60℃ for from about 5 minutes to about 10 minutes and when the top coating layer is a waterborne UV topcoat then at a temperature of from about 60℃ to about 120℃ for from about 5 minutes to about 30 minutes -670;

- exposing the coated substrate to ultraviolet light at 700 -1, 300 mJ/cm ² for 10-30 seconds -680.

In another example, as shown in FIG. 6, the method 600 includes:

- providing a non-metal substrate-640;

- applying a waterborne primer coating layer on the non-metal substrate at a temperature of from about 80℃ to about 120℃ for from about 3 minutes to about 40 minutes -630;

- applying a waterborne base coating layer on the waterborne primer coating layer at a temperature of from about 80℃ to about 120℃ for from about 3 minutes to about 40 minutes -650;

- applying a top coating layer -660;

- exposing the coated substrate to ultraviolet light at 700 -1,300 mJ/cm ² for 10-30 seconds -680.

In the above example, the non-metal substrate comprises plastic, carbon fiber, composite material, or combinations thereof.

Definitions

It is noted that, as used in this specification and the appended claims, the singular forms "a, " "an, " and "the" include plural referents unless the content clearly dictates otherwise.

The term "about" as used herein, when referring to a numerical value or range, allows for a degree of variability in the value or range, for example, within 5%or other reasonable added range breadth of a stated value or of a stated limit of a range. The term “about” when modifying a numerical range is also understood to include the exact numerical value indicated, e.g., the range of about 1 wt%to about 5 wt%includes 1 wt%to 5 wt%as an explicitly supported sub-range.

As used herein, “colorant” can include dyes and/or pigments.

As used herein, “dye” refers to compounds or molecules that absorb electromagnetic radiation or certain wavelengths thereof. Dyes can impart a visible color to an ink if the dyes absorb wavelengths in the visible spectrum.

As used herein, “pigment” generally includes pigment colorants, magnetic particles, aluminas, silicas, and/or other ceramics, organo-metallics or other opaque particles, whether or not such particulates impart color. Thus, though the present description primarily exemplifies the use of pigment colorants, the term “pigment” can be used more generally to describe pigment colorants and other pigments such as organometallics, ferrites, ceramics, etc. In one specific example, however, the pigment is a pigment colorant.

As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though the individual members of the list are individually identified as a separate and unique member. Thus, no individual member of such list should be construed as a de facto equivalent of any other member of the same list solely based on their presentation in a common group without indications to the contrary.

Concentrations, dimensions, amounts, and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include the numerical values explicitly recited as the limits of the range, and also to include all the individual numerical values or sub-ranges encompassed within that range as if individual numerical values and sub-ranges are explicitly recited. For example, a layer thickness from about 0.1 μm to about 0.5 μm should be interpreted to include the explicitly recited limits of 0.1 μm to 0.5 μm, and to include thicknesses such as about 0.1 μm and about 0.5 μm, as well as subranges such as about 0.2 μm to about 0.4 μm, about 0.2 μm to about 0.5 μm, about 0.1 μm to about 0.4 μm etc.

Claims

A cover for an electronic device comprising:

a substrate;

a waterborne primer coating layer on a surface of the substrate;

a waterborne base coating layer on the primer coating layer; and

a top coating layer on the waterborne base coating layer, wherein the top coating layer comprises a waterborne UV topcoat and/or a UV topcoat,

wherein the waterborne UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof, and (iii) water in an amount of from about 5 wt%to about 15 wt%based on the total weight of the waterborne UV topcoat, and

wherein the UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof, and (iii) at least one organic solvent.
The cover of claim 1, wherein the substrate comprises plastic, carbon fiber, composite material, a metal, or combinations thereof.
The cover of claim 2, wherein the metal comprises aluminum and aluminum alloys, titanium and titanium alloys, stainless steel, magnesium and magnesium alloys, aluminum and aluminum alloys, lithium and lithium alloys, and combinations thereof.
The cover of claim 1, wherein the waterborne primer coating layer has a thickness of from about 10 μm to about 30 μm.
The cover of claim 1, wherein the waterborne base coating layer has a thickness of from about 10 μm to about 25 μm.
The cover of claim 1, wherein the top coating layer has a thickness of from about 15 μm to about 25 μm.
An electronic device comprising:

an electronic component; and

a cover enclosing the electronic component, the cover comprising:

a metal substrate;

a micro-arc oxidation layer or a passivation layer on at least one surface of the metal substrate;

an optional powder coating layer on the passivation layer;

a waterborne primer coating layer on the micro-arc oxidation layer or the passivation layer or the optional powder coating layer;

a waterborne base coating layer on the primer coating layer; and

a top coating layer on the waterborne base coating layer, wherein the top coating layer comprises a waterborne UV topcoat and/or a UV topcoat,

wherein the waterborne UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof, and (iii) water in an amount of from about 5 wt%to about 15 wt%based on the total weight of the waterborne UV topcoat, and

wherein the UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof, and (iii) at least one organic solvent.
The electronic device of claim 7, wherein the electronic device is a laptop, a desktop computer, a keyboard, a mouse, a smartphone, a tablet, a monitor, a television screen, a speaker, a game console, a video player, an audio player, or a combination thereof.
The electronic device of claim 7, wherein the metal comprises aluminum and aluminum alloys, titanium and titanium alloys, stainless steel, magnesium and magnesium alloys, aluminum and aluminum alloys, lithium and lithium alloys, and combinations thereof.
The electronic device of claim 7 comprises the powder coating layer.
The electronic device of claim 7, wherein the passivation coating layer has a thickness of from about 1 μm to about 5 μm.
The electronic device of claim 7, wherein the micro-arc oxidation layer has a thickness of from about 2 μm to about 15 μm.
A method of making a cover for an electronic device comprising:

forming a micro-arc oxidation layer or a passivation layer on at least one surface of a metal substrate;

applying an optional powder coating layer on the passivation layer;

applying a waterborne primer coating layer on the micro-arc oxidation layer or the passivation layer or the optional powder coating layer;

applying a waterborne base coating layer on the primer coating layer; and

applying a top coating layer on the waterborne base coating layer, wherein the top coating layer comprises a waterborne UV topcoat and/or a UV topcoat,

wherein the waterborne UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof, and (iii) water in an amount of from about 5 wt%to about 15 wt%based on the total weight of the waterborne UV topcoat, and

wherein the UV topcoat comprises (i) a polyacrylic, a polyurethane, a urethane acrylate, an acrylic acrylate, an epoxy acrylate, or combinations thereof, (ii) silanes, fluorinated olefin-based polymers, specialty fluoroacrylates, fluorosilicone acrylates, fluorourethanes, perfluoropolyethers, perfluoropolyoxetanes, fluorotelomers, polytetrafluoroethylene, polyvinylidenefluouride, fluorosiloxane, fluoro UV polymers, or combinations thereof, and (iii) at least one organic solvent.
The method of claim 13, wherein the metal comprises aluminum and aluminum alloys, titanium and titanium alloys, stainless steel, magnesium and magnesium alloys, aluminum and aluminum alloys, lithium and lithium alloys, and combinations thereof.
The method of claim 13, wherein:

the passivation coating layer has a thickness of from about 1 μm to about 5 μm; and

the micro-arc oxidation layer has a thickness of from about 2 μm to about 15 μm.