CN104694995B

CN104694995B - Surface treatment method for conductive substrate

Info

Publication number: CN104694995B
Application number: CN201510073224.XA
Authority: CN
Inventors: 郭筠彤
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-09-16
Filing date: 2015-02-12
Publication date: 2021-05-11
Anticipated expiration: 2035-02-12
Also published as: CN104342739A; CN104694995A

Abstract

The invention discloses a surface treatment method of a conductive substrate, which comprises the following steps: one or two of the pretreatment of wire drawing, sand blasting or polishing is carried out on the surface of the conductive base material; then, carrying out first electrophoretic coating or spraying treatment to form a layer of first electrophoretic paint or spraying paint which is colored and is different from the primary color of the conductive base material; then, carrying out first laser etching or diamond etching treatment to form a first pattern exposing the primary color of the conductive base material and a second pattern with reduced thickness of first electrophoresis (or spraying) paint; then, a roughening treatment is carried out, including chemical roughening (weak acid or weak base or forming a film), physical roughening (plasma bombardment or sand blasting), and then, a second electrophoretic coating or spraying treatment is carried out to form a colored high-transparency electrophoretic (or spraying) paint or a completely colorless very high-transparency electrophoretic (or spraying) paint.

Description

Surface treatment method for conductive substrate

Technical Field

The present invention relates to the field of surface treatment technology, and more particularly to a surface treatment method for conductive substrate.

Background

The electrophoretic coating process has the advantages of easy automatic control, no toxicity, environmental protection, plumpy, uniform, flat and smooth coating and the like, and the hardness, adhesive force, corrosion resistance, impact resistance and the like of the electrophoretic coating are obviously superior to those of other coating processes, so the electrophoretic coating process is widely applied to the coating treatment of the surface of a workpiece.

Previously, in the electrophoretic coating process, only the appearance of a product with a single color effect can be produced, and the appearance effect of different colors cannot be formed on the surface of the product, and then, the industry has studied and improved the same, for example, the coating method disclosed in the patent document with the application number 201110406662.5, which forms a first coating layer by performing a first color electrophoresis on the surface of a substrate, wherein the electrophoresis voltage is 150-; then, carrying out first laser engraving, removing the first coating layer from the engraved part, carrying out second electrophoretic coating, and forming a second coating layer with a color different from that of the first coating layer on the part subjected to the first laser engraving treatment, so that different colors are obtained on the surface of the substrate, and the surface of the substrate presents a colorful appearance effect; the metal substrate that can be processed by the above process includes stainless steel, aluminum or aluminum alloy.

Another electrophoretic coating technique, for example, in patent document No. 201210413241.X, is to perform multiple electrophoretic treatments on the surface of stainless steel, and the first color electrophoresis is to form an insulating coating layer for coating the color of a substrate; then, forming a first pattern by first laser etching, and removing the corresponding coating layer to expose the stainless steel substrate; then, carrying out second color electrophoresis to paint colors on the first pattern; the coating colors of the first color electrophoresis and the second color electrophoresis are different; in another embodiment, a second laser etching is performed to form a second pattern, and the corresponding coating layer is removed; then, carrying out third color electrophoresis to paint colors for the second pattern; the coating color of the third color electrophoresis is different from that of the second color electrophoresis; and the second pattern and the first pattern have no overlapping part, so as to avoid damaging the effect of the first-time color electrophoretic layer. Before the first color electrophoresis, the method also comprises the steps of chemical degreasing and/or electrolytic degreasing, 5-8% sulfuric acid neutralization, tap water washing or pure water washing and the like; after each electrophoretic coating, the method also comprises the steps of dehydration and drying, and also comprises a step of pure water washing for a plurality of times before the second electrophoresis and the third electrophoresis.

The first laser etching step is to completely etch through the preset area of the first electrophoretic coating layer and to perform a second electrophoretic process after the conductive layer is exposed; although the first laser power is adjusted to 85-95%, the speed is 1000 +/-150 mm/s, the filling line interval is 0.05-0.08mm, the second laser etching is adjusted to 60-70%, and the area of the second laser etching is completely etched through.

In the two coating technologies, the multi-color effect is established on the times of electrophoretic coating, two colors can be presented by secondary electrophoresis, and the second electrophoretic layer is only limited to the conductive area etched through by the first laser etching; more times of electrophoretic coating and more times of laser engraving are needed, and the multicolor effect can be presented only when the electrophoretic coating pigment is different each time; in addition, the position of the second electrophoretic layer coating is to supplement another color in the carving-through area after the first electrophoretic layer, so that the whole workpiece surface has no color level change and no stereoscopic impression; therefore, a new surface treatment method needs to be developed to solve the above problems.

Disclosure of Invention

The present invention is directed to the disadvantages of the prior art, and the main objective of the present invention is to provide a method for treating the surface of a conductive substrate, which forms a multi-color layered or even three-dimensional coating layer by a single electrophoretic coating layer, a first pattern of the exposed conductive substrate with a primary color and a second pattern of the electrophoretic coating layer with a reduced thickness by performing a laser etching or diamond etching process.

In order to achieve the purpose, the invention adopts the following technical scheme:

a surface treatment method for conductive substrate at least comprises the following steps:

carrying out first electrophoresis treatment to form a layer of first electrophoretic paint which is colored and is different from the primary color of the conductive base material on the surface of the conductive base material;

and carrying out laser etching or diamond etching treatment to form a first pattern for removing the primary color of the first electrophoretic paint exposed on the conductive base material and a second pattern with reduced thickness of the first electrophoretic paint.

Preferably, the method further comprises one or two of pre-treatments of wire drawing, sand blasting or polishing on the surface of the conductive substrate before the first electrophoresis treatment.

Preferably, an anodic coloring treatment step is further included when the conductive substrate is aluminum or an aluminum alloy before the first electrophoretic treatment.

Preferably, the first pattern and the second pattern with the first electrophoretic paint thickness reduced are completed by one-time laser etching or drilling etching according to a program.

Preferably, the second pattern of the first electrophoretic paint with reduced thickness is formed by programming a one-time laser etching or diamond etching process using a laser knife inclined at a predetermined angle.

As a preferred scheme, after laser etching or diamond etching treatment, the method also comprises the following steps in sequence:

performing at least one of sand blasting, chemical roughening, film formation and plasma treatment;

and performing a second electrophoretic treatment to form a colored or colorless completely transparent second electrophoretic paint layer, wherein the second electrophoretic paint layer is formed on the first pattern and the second pattern.

one or two of the pretreatment of wire drawing, sand blasting or polishing is carried out on the surface of the conductive base material;

carrying out first electrophoresis treatment to plate a layer of first electrophoretic paint which is colored and is different from the primary color of the conductive base material on the surface of the conductive base material;

carrying out first spraying treatment to plate a layer of first spraying paint which is colored and is different from the primary color of the conductive base material on the surface of the conductive base material;

performing laser etching or diamond etching treatment to form a first pattern for removing the primary color of the first spraying paint exposed on the conductive base material and a second pattern with reduced thickness of the first electrophoretic paint;

a second spray treatment is carried out to form a clear spray paint without coloring, which is formed indiscriminately on the surface of the result.

Compared with the prior art, the invention has obvious advantages and beneficial effects, and specifically, the technical scheme includes that:

(1) the conductive base material which can be processed is not limited to stainless steel, iron or carbon steel and other metals, and the first pattern which is carved through is covered by the subsequent high-transparency second electrophoretic coating layer or high-transparency spraying layer, so that the anti-corrosion effect is achieved;

(2) the laser etching pattern comprises a first pattern (etching area) and a second pattern (thinned electrophoretic coating layer), and can generate multicolor layering effect only by one electrophoretic coating layer;

(3) when the laser etching pattern comprises a first pattern (etching through area) and a second pattern (thinned electrophoresis coating layer) which are adjacent patterns, a three-dimensional pattern feeling can be generated;

(4) further, aluminum or aluminum-magnesium alloy which is subjected to the anodic coloring treatment may be treated.

To more clearly illustrate the structural features and technical means of the present invention and the specific objects and functions achieved thereby, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.

Drawings

FIG. 1 is a schematic flow chart of a surface treatment method according to a preferred embodiment of the present invention;

FIG. 2A is a schematic cross-sectional view of an embodiment of the present invention after a first electrophoresis (or spraying);

FIG. 2B is a schematic cross-sectional view of a laser etching process after a first electrophoresis (or spraying) process according to a first embodiment of the present invention;

FIG. 2C is a schematic cross-sectional view of a tilted laser blade after a first electrophoresis (or spray) and laser etching of a thinned region according to a second embodiment of the present invention;

FIG. 2D is a schematic cross-sectional view of the first embodiment of the present invention after the first electrophoresis (or spraying), laser etching and the second electrophoretic coating;

FIG. 2E is a schematic cross-sectional view of the first embodiment of the present invention after the first electrophoresis (or spraying), laser etching and further spraying;

FIG. 2F is a schematic cross-sectional view of a second embodiment of the present invention after a first electrophoresis (or spraying), a laser etching, and a second electrophoretic coating;

FIG. 2G is a schematic cross-sectional view of a second embodiment of the present invention after a first electrophoresis (or spraying), a laser etching, and a coating spraying;

FIG. 2H is a schematic cross-sectional view of a first embodiment of the present invention, which is performed with an anodization coloring process before a first electrophoresis (or spraying);

FIG. 2I is a schematic cross-sectional view of a first embodiment of the present invention, in which an anodization coloring process is performed before a first electrophoresis (or spraying) and laser etching;

FIG. 3A is a real photograph of the electrophoresis and laser etching of the present invention showing multi-level colors;

FIG. 3B is a schematic diagram of the laser etching pattern shown in FIG. 3A;

FIG. 3C is a schematic view of a laser engraved pattern viewed from the side (which shows more pronounced stereoscopic impression);

FIG. 4 is a real photo of the electrophoresis and laser etching of the present invention showing multi-level colors;

FIG. 5A is a partial cross-sectional view of a third embodiment of the present invention, in which a paint layer 61 is further covered in the first pattern (e.g. dual-color effect);

FIG. 5B is a partial cross-sectional view of a third embodiment of the present invention, in which a laser etching process is further performed on the lacquer layer 61 shown in FIG. 5A.

The attached drawings indicate the following:

10. conductive base material

20. Anodic oxidation coloring (aluminum oxide or aluminum magnesium oxide)

30. Electrophoretic paint

41. First pattern

42. 42' second pattern

43. Third pattern

50. Transparent non-colored or transparent colored electrophoretic paint

51. Transparent non-colored spray paint

61. Paint layer

62. Fourth pattern

V, is not finished product

X, do not carry out the step

Very good, the product may be obtained until this step is shown.

Detailed Description

Referring to FIG. 1, a surface flow of various conductive substrates of the present invention, such as stainless steel, carbon steel, iron, aluminum-magnesium alloy, etc., is shown; wherein the step is not performed on the X surface; the symbols x represent the step, and can be finished products or the next step is selected to be continued; note V indicates that this step is not yet an end point, is not a finished product, and requires the next step.

First, a first surface pretreatment is performed on the surface of a conductive substrate, for example, a workpiece such as stainless steel, carbon steel, iron, aluminum-magnesium alloy, etc., and the first surface pretreatment is performed by first performing a wire drawing, sand blasting, polishing, etc., on the surface of the conductive substrate, depending on the customization requirements. The surface of the conductive base material is subjected to wire drawing, the wire drawing effect can be generated after electrophoretic coating, the wire drawing is not limited to a straight line, and a curve is also available, and the wire drawing can be determined according to customization requirements; the sand blasting treatment can ensure that the subsequent surface treatment layer is more stable in the laser engraving process or after the processing.

Then, a second surface pretreatment is performed, which is to perform processes of removing surface grease, washing, drying, etc. on the surface of the workpiece to remove the contamination particles on the surface of the workpiece, for example, in the conventional technique, the purpose of the second surface pretreatment is to prevent the grease or the contamination particles from affecting the adhesion of the electrophoretic paint layer.

Referring to the cross-sectional view of fig. 2A, a first electrophoretic coating process is performed to coat a layer of electrophoretic paint 30 with a color different from the conductive substrate 10 by about 15-30 μm. Optionally, the aluminum or aluminum-magnesium alloy is anodized and colored before the first electrophoretic coating process (please refer to fig. 2H), and after the anodization and coloring process, the aluminum or aluminum-magnesium alloy forms an aluminum oxide layer or aluminum-magnesium oxide layer 20 with poor conductivity, the thickness of which is about 2-10 μm; at this time, in the first electrophoretic coating treatment, the working voltage during electrophoresis is increased by about 20-50%, or the distance between the anode and the cathode is reduced to increase the electric field intensity; when the electric field intensity is increased, the moving speed of the electrophoretic paint ions can be accelerated, the electrophoretic coating time can be shortened, and the electric field intensity can also penetrate through the aluminum oxide layer or the aluminum-magnesium oxide layer with weak conductivity on the surface of the conductive substrate 10, so that the subsequent electrophoretic coating treatment can be smoothly carried out.

Drying after electrophoresis, as in the conventional technique. Subsequently, a first laser engraving (laser engraving) or diamond engraving is performed, wherein the laser engraving process includes forming a predetermined first pattern 41 and a second pattern 42 with a reduced thickness according to an embodiment of the present invention, and as a result, as shown in fig. 2B or fig. 2I (including the anodized coloring layer 20); the first pattern 41 is formed by engraving the corresponding electrophoretic paint in the pattern to expose the primary color of the conductive substrate 10, or to expose the anodized coloring layer 20 as shown in fig. 2I; the second pattern 42 is formed by thinning the corresponding electrophoretic paint in the pattern, for example, the thickness of 20 μm of electrophoretic paint is reduced to 5 μm-16 μm, the same area in the thinned area is thinned equally, and the thinning degree may be different in different areas, for example, the thickness of 42' in the second pattern is reduced less.

In another embodiment (i.e. the second embodiment), the thinning area is varied, the pattern thinning is not limited to "equal thickness" thinning, but may also be in the form of "wedge" thinning, etc., and during laser etching, the laser knife is tilted at an angle to thin, so that the engraved pattern is more stereoscopic, as shown in fig. 2C.

When the surface of the workpiece is a plane, such as a television frame or a mobile phone shell, the thickness of the first electrophoretic paint in each area of the surface of the workpiece is approximately the same, so that the local thickness reduction of the electrophoretic paint is relatively easy to control; when the electrophoretic paint is locally thinned instead of being pierced, a visual effect of color gradation, or a three-dimensional pattern effect, is thus produced, which is due to the fact that when the electrophoretic paint is locally thinned, the light transmittance is different from the original thickness (non-engraved area), or zero thickness (the electrophoretic paint is entirely pierced), especially when the second pattern is related to the lines of the first pattern, for example, the mesophyll position of the leaf is the thinned area, and branches, stems are pierced, as shown in the photograph shown in fig. 3A; fig. 3B is a schematic diagram illustrating the laser engraved pattern of fig. 3A, and fig. 3C is a photograph of the laser engraved pattern viewed from the side, which clearly shows a three-dimensional pattern.

The electrophoretic paint through-carving or local thickness reduction is achieved by adjusting energy with laser power. In another embodiment, the variation of the pulse width of the laser can be controlled to achieve the laser or simultaneously achieve the laser with the laser knife with the inclined angle; that is, in the present invention, the laser power is not constant or the pulse width is not constant during the laser etching process, and it varies depending on the position of the laser etching pattern, and the variation is program-controlled.

According to another embodiment of the present invention, when the first pattern is only the border of the first electrophoretic coating, referring to fig. 4, it is able to generate more than two colors after laser etching of the first electrophoretic coating, especially, when the wedge-shaped thinning is performed, it can display more colors and three-dimensional effect, i.e. the laser etching is different from the conventional techniques of at least two electrophoretic coatings and two laser etching to generate two colors.

According to the embodiment of the present invention, a multi-color gradation effect can be produced by one electrophoretic coating process and one (or more) laser etching process, for example, laser etching the second pattern 42 and performing the third pattern 43 separately at the same time, i.e., the third pattern is thinned to a different degree than the second pattern 42 (see fig. 2A to 2C).

The conductive substrate workpiece can be a finished product after the first laser engraving, except carbon steel and iron; after the carbon steel or iron electrophoretic coating forms the first pattern (is carved through), no protective layer is arranged, so that the rust can be generated, therefore, the carbon steel or iron conductive base material must be subjected to second electrophoretic coating or spraying treatment, and other conductive base materials can be selectively subjected to second electrophoretic coating.

According to an embodiment of the present invention, the second electrophoretic coating or spraying treatment is preceded by a third pretreatment, wherein the third pretreatment is to perform a chemical roughening, a film treatment or a physical roughening, such as sand blasting or plasma treatment, on the workpiece after the first laser etching is completed, and the third pretreatment can increase the adhesion of the second electrophoretic coating or spraying layer. The third pretreatment is based on the principle that the previous laser carving pattern is not damaged, so that the particles are fine during sand blasting, for example, the sand blasting particles are glass sand of No. 200, and the pressure is between 2 and 4 kilograms; chemical roughening refers to wiping or dipping the surface of a workpiece (iron or steel) with weak acid or wiping or dipping the workpiece (aluminum or aluminum-magnesium alloy) with weak base, or generating a film on the surface of the workpiece so as to generate an extremely thin film on the surface of the workpiece; the plasma is generated under high pressure of inert gas and directly bombards the surface of the workpiece.

The result of the second electrophoretic coating or spraying process is shown in fig. 2D-2G, wherein a colored but highly transparent secondary electrophoretic coating 50 is formed on the first pattern and the second pattern 42 (42 ') and the third pattern 43 with reduced thickness, as shown in fig. 2C or 2F, wherein the second pattern 42 (42') and the third pattern 43 with reduced thickness are less conductive than the first pattern 41 (exposed on the surface of the conductive substrate 10), and therefore the electric field (or anode voltage) is increased. However, in the present invention, it is not desirable to have a second electrophoretic coating on the first electrophoretic coating that is laser etched to avoid having a second electrophoretic coating thereon that is not uniform in thickness, such as sharp, particularly thick; on the other hand, in order to avoid the second electrophoretic coating from damaging the original color; therefore, the electric field is properly adjusted and controlled, and in one embodiment, the voltage is about 30-50% higher than that of the first electrophoresis.

The first pattern 41, the second pattern 42 (42') with reduced thickness, and the third pattern 43 are covered completely, and the thickness reduction area is not formed, but the spraying process is preferably performed without selection, as shown in fig. 2D or fig. 2G.

As shown in fig. 5A, the first pattern 41 is further covered with a paint layer 61 as a coloring layer, which covers the original primary color of the substrate body 10 to form the actual required color, and the effect can be achieved as shown in fig. 4; as shown in fig. 5B, a fourth pattern 62 is further formed on the surface of the paint layer 61 by laser etching or diamond etching, a portion of the original color of the substrate body 10 can be exposed, and the bottom surface of the wedge-shaped structure design formed by the inclined surface structure or the inclined surfaces thereof enables the remaining paint layer at the corresponding bottom of the fourth pattern 62 to show a gradual color effect.

From the above, it can be seen that the present invention has the following advantages:

The above description is only a preferred embodiment of the present invention, and is not intended to limit the technical scope of the present invention, so that any minor modifications, equivalent changes and modifications made to the above embodiment according to the technical spirit of the present invention are within the technical scope of the present invention.

Claims

1. A surface treatment method for a conductive substrate is characterized in that: the method at least comprises the following steps:

2. The method of claim 1, further comprising the steps of: before the first electrophoresis treatment, one or two of pretreatments of wire drawing, sand blasting or polishing are carried out on the surface of the conductive substrate.

3. The method of claim 1, further comprising the steps of: before the first electrophoresis treatment, when the conductive substrate is aluminum or aluminum alloy, an anode coloring treatment step is also included.

4. The method of claim 1, further comprising the steps of: the first pattern and the second pattern with the first electrophoretic paint thickness reduced are finished by one-time laser etching or drilling etching treatment according to program planning.

5. The method of claim 1, further comprising the steps of: the second pattern with the first electrophoretic paint thickness reduced is finished by programming one-time laser etching or drilling etching treatment by a laser knife inclined at a preset angle.

6. The method for surface treatment of an electrically conductive substrate as set forth in claim 1 or 2, wherein: after laser etching or diamond etching treatment, the method also comprises the following steps in sequence:

7. A surface treatment method for a conductive substrate is characterized in that: at least comprises the following steps:

8. The method of claim 7, further comprising the steps of: before the first electrophoresis treatment, when the conductive substrate is aluminum or aluminum alloy, an anode coloring treatment step is also included.

9. The method of claim 7, further comprising the steps of: the first pattern and the second pattern with the first electrophoretic paint thickness reduced are finished by one-time laser etching or drilling etching treatment according to program planning.

10. A surface treatment method for a conductive substrate is characterized in that: at least comprises the following steps: