Copper product surface turquoise hot coloring preparation method

Abstract

The invention discloses a preparation method for surface turquoise hot coloring of a copper product. The preparation method comprises the following steps: (1) pretreatment; (2) preparing a white reagent for bottoming, a blue reagent for coloring and a green reagent; (3) surface coloring: spraying a white medicament on the surface of the copper piece in a mist form by using a sprinkling can, drying under the action of a hot air gun, and repeating for multiple times until a uniform white priming coat appears on the surface of the copper piece; alternately and repeatedly spraying a blue medicament and a green medicament on the white priming layer in a mist form by using a spraying can, and simultaneously drying under the action of a hot air gun for multiple times until a uniformly and gradually changed blue-green coloring layer appears on the surface of the copper piece; and (4) post-treatment is conducted, specifically, the colored copper part is dried and then cooled to the room temperature, varnish is sprayed to seal the surface, and inspection is conducted after drying. The process is relatively simple, coloring is uniform and rapid, operation safety is high, a formed film is bright in color and luster, the color film is firm, and cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of copper product processing, and in particular to a method for preparing a copper product surface with a cyan thermal coloration. Background Art

[0002] Copper is the earliest metal used by humans and occupies an extremely important position in the world's smelting history. my country has experienced a glorious copper age and has left many exquisite copper craft art works in history. Copper and copper alloy products have been widely used in handicrafts, accessories, and artistic creations, and are loved and sought after by everyone. In chemical decoration, copper surface coloring actually makes the metal copper interact with the chemical solution to form a surface oxide layer, sulfide layer or other compound layer, which strengthens the copper surface, improves the overall performance or changes its color presentation.

[0003] Traditional bronze coloring methods mostly use cold coloring or natural coloring, which is to place the copper pieces outdoors or bury them in the soil, add some formulas, and let them slowly change color on the surface. Nowadays, chemical bronze coloring is more common. Chemical copper coloring uses heating as a catalyst to promote chemical reactions between compounds and the bronze surface, and naturally produces various colors to achieve the effect of decorating the bronze surface. The color of the copper surface, the traditional color spots, are generally monotonous: limited to a few colors such as green rust, iron red spots, and black tones.

[0004] With the development of society, chemical technologies for metal surface decoration and protection, such as chemical plating, oxidation heating coloring, and room temperature chemical coloring, have emerged one after another. The traditional room temperature production method of copper green has a long cycle, slow effect, great environmental impact, difficult color control, and easy further oxidation after sealing, and the adhesion of the coloring film is also relatively poor. The traditional flame thermal coloring method has high technical operation difficulty, high site requirements and equipment investment, and there are also relatively large safety hazards in actual operation. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing blue-green thermal coloring of the surface of a copper product, which has a relatively simple process, uniform and rapid coloring, high operation safety, bright film color, firm color film and low cost.

[0006] The technical solution adopted by the present invention to solve its technical problem is: A method for preparing a cyan thermal coloration of a copper product surface comprises the following steps: (1) Pretreatment: Prepare copper products, sandblast or chemically pickle the surface of the copper parts to remove the surface oxide layer and oil stains, then further polish and clean them with a scouring pad in water, then rinse with clean water and blow dry; prepare a copper blackening agent solution, immerse the copper parts in the copper blackening agent solution for 2 to 5 seconds, then rinse with clean water and immerse again in the copper blackening agent solution for 3 to 5 seconds, finally rinse and dry for use; (2) Prepare white reagent for base coating, and blue and green reagents for coloring; (3) Surface coloring: Place the copper piece treated in step (1) in a 120°C oven for preheating for 5-10 minutes, take it out and use a heat gun to maintain its surface temperature at 70-120°C; Use a spray pot to spray the white agent on the surface of the copper piece in a mist form and dry it with a hot air gun. Repeat this process several times until a uniform white base layer appears on the surface of the copper piece. Use a spray pot to spray the blue and green agents alternately on the white base layer in a mist form and dry them with a hot air gun. Repeat this process several times until a uniform gradient blue-green coloring layer appears on the surface of the copper piece. (4) Post-processing: Dry the colored copper parts and cool them to room temperature, spray varnish to seal the surface, and inspect them after drying.

[0007] The present invention is characterized in that an improved thermal coloring process is combined with a specific cyan formula, thereby forming a new cyan color system on the surface of the copper product. The coloring is uniform and fast, the film is bright in color, and the color film is firm. The copper parts use conventional 62~68 brass or red copper. Step (3) spraying with a spray pot can obtain a more uniform film layer with strong adhesion, which is conducive to the reaction of the potion with the substrate and obtains good mechanical properties. The blackening treatment is combined with a white base layer to better cover the base color. A simple white base layer easily reveals the base color, resulting in poor color development.

[0008] Use a spray pot to spray the blue and green agents alternately on the white base layer in a mist form, and dry them with a hot air gun. Repeat this process many times. Specifically, spray the blue agent immediately after spraying the green agent, or spray the green agent immediately after spraying the blue agent, dry them with a hot air gun, then spray the blue agent immediately after spraying the green agent, or spray the green agent immediately after spraying the blue agent, dry them with a hot air gun, and repeat this process.

[0009] For the cyan color, the present invention designs a specific formula, wherein copper nitrate, copper sulfate, and nickel sulfate are used as mordants and metal colorants, and directly react with copper at a certain temperature in the formula to form a certain cyan color, and further color development is achieved by mixing with inorganic pigments. Copper sulfate and nickel sulfate are also relatively active in nature. In addition to enhancing color development, they can also improve color saturation and make the colors more vivid. Bismuth nitrate in the formula itself has strong oxidizability, and is reactive and slightly corrosive to the copper surface with copper nitrate, copper sulfate, and nickel sulfate raw materials in the formula. The compounding of several raw materials has a mutual synergistic effect, which can not only form a relatively stable oxide film on the surface of the copper substrate, but also produce a certain adhesion effect on the inorganic pigment, thereby improving the color film fastness. Since bismuth nitrate is slightly soluble in water, easily soluble in nitric acid and ethylene glycol, and easily undergoes hydrolysis in aqueous solution, in order to prevent bismuth nitrate from hydrolyzing and performance degradation, nitric acid and ethylene glycol are added to the formula as auxiliary solvents for water. At the same time, since nitric acid also has a corrosive effect on the copper surface, it can further enhance the reactivity and bonding between the reactants and the copper substrate, and further improve the adhesion of the coloring layer. In addition to assisting in inhibiting the hydrolysis of bismuth nitrate and increasing its solubility in water, ethylene glycol can also enhance the dispersibility, uniformity and color development of the pigment in the formula due to its low molecular weight, active properties and high miscibility with water, and can also make the color of the coloring film layer delicate and uniform, further enhancing the color presentation.

[0010] In addition, with regard to the coloring process, the present invention also designs a hot air gun heating coloring process that is different from the traditional flame coloring process. The thermal coloring temperature is lower, the technical operation difficulty is relatively lower, and the operation safety is higher.

[0011] Preferably, the white agent formula is: bismuth nitrate 12-20g / L, copper nitrate 0.3-2g / L, copper sulfate 0.3-3g / L, nickel sulfate 0.4-3g / L, nitric acid 5-20ml / L, ethylene glycol 20-50ml / L, titanium dioxide 10-30g / L, and water as the balance.

[0012] Preferably, the blue agent formula is: bismuth nitrate 12-20g / L, copper nitrate 0.3-2g / L, copper sulfate 0.3-3g / L, nickel sulfate 0.4-3g / L, nitric acid 5-20ml / L, ethylene glycol 20-50ml / L, phthalocyanine blue 8-15g / L, and water as the balance.

[0013] Preferably, the green agent formula is: bismuth nitrate 12-20g / L, copper nitrate 0.3-2g / L, copper sulfate 0.3-3g / L, nickel sulfate 0.4-3g / L, nitric acid 5-20ml / L, ethylene glycol 20-50ml / L, cobalt green 8-15g / L, and water as the balance.

[0014] Preferably, the mass concentration of nitric acid is 5-10%.

[0015] Preferably, in step (1), the copper blackening agent solution is prepared by mixing copper blackening agent: water in a mass ratio of 1:2-4.

[0016] Preferably, in step (1), the chemical pickling solution of the chemical pickling treatment has a formula of: 100 to 120 mL / L of concentrated sulfuric acid, 30 to 50 mL / L of concentrated hydrochloric acid, 6 to 9 g / L of urea, 0.8 to 1.2 mL / L of OP-10 emulsifier, and the balance of water.

[0017] Preferably, the mass concentration of concentrated sulfuric acid is 98%, and the mass concentration of concentrated hydrochloric acid is 36%.

[0018] The beneficial effects of the present invention are: 1. Compared with the traditional flame coloring process, the present invention can obtain a cyan colored oxide film layer with good mechanical properties, bright colors and natural gradient on the surface of copper handicrafts; bismuth nitrate combined with ethylene glycol and nitric acid can effectively prevent bismuth nitrate from hydrolyzing, and at the same time enhance the adhesion between the copper substrate and the oxide film; 2. The color produced by the process of the present invention is uniform, bright and saturated, and has good color development; 3. Since a hot air gun is used as a heating tool, not only the coloring temperature is lower, but the operation is also more convenient and safer; 4. The process is simple and easy to realize automated production, which has great promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a comparison chart of adhesion of different formulas in a hundred grid tests; Figure 2 This is a comparison chart of the color effects of different formulas; Figure 3 It is a schematic diagram of a red copper kettle product processed by the method of the present invention; Figure 4 It is a schematic diagram of a brass cup holder product processed by the method of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described in detail below through specific embodiments.

[0021] In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. The methods in the following embodiments, unless otherwise specified, are all conventional methods in the art.

[0022] Embodiment 1: A method for preparing a cyan thermal coloration of a copper product surface comprises the following steps: (1) Pretreatment: Prepare copper products (red copper kettles), sandblast the surface of the copper parts to remove the surface oxide layer and oil stains, then further polish and clean them with a scouring pad in water, then rinse with clean water and blow dry; Prepare copper blackening agent solution: mix copper blackening agent (Q / YS.108 (Yishun brand)) and water in a mass ratio of 1:3; immerse the copper piece in the copper blackening agent solution for 3 seconds, then rinse it with clean water and immerse it again in the copper blackening agent solution for 4 seconds, finally rinse it and dry it for use; (2) Prepare the white agent for primer: 15 g / L bismuth nitrate, 1 g / L copper nitrate, 1.5 g / L copper sulfate, 1.5 g / L nickel sulfate, 10 ml / L 5% nitric acid, 35 ml / L ethylene glycol, 15 g / L titanium dioxide, and the balance water; Prepare blue reagent: bismuth nitrate 15g / L, copper nitrate 1g / L, copper sulfate 1.5g / L, nickel sulfate 1.5g / L, 5% nitric acid 10ml / L, ethylene glycol 35ml / L, phthalocyanine blue 10g / L, balance water; Prepare green reagent: bismuth nitrate 15g / L, copper nitrate 1g / L, copper sulfate 1.5g / L, nickel sulfate 1.5g / L, 5% nitric acid 10ml / L, ethylene glycol 35ml / L, cobalt green 10g / L, balance water; (3) Surface coloring: Place the copper piece treated in step (1) in a 120°C oven for preheating for 10 minutes, take it out and use a heat gun to maintain its surface temperature at 120°C; Use a spray pot to spray the white agent on the surface of the copper piece in a mist form and dry it with a hot air gun. Repeat this process several times (about 100 times) until a uniform white base layer appears on the surface of the copper piece. Use a spray pot to spray the blue and green agents alternately on the white base layer in a mist form, and dry them with a hot air gun. Repeat this process several times (about 100 times) until a uniform gradient blue-green coloring layer appears on the surface of the copper piece. (4) Post-treatment: After drying the colored copper parts, cool them to room temperature, spray the varnish primer at 50℃, preheat them in an oven at 80℃ for 10 minutes, and then bake them at 150℃ for 30 minutes to thoroughly dry the primer. Then, after the temperature drops to room temperature, use fine sandpaper to gently polish the surface until it is smooth, spray the varnish topcoat, preheat them in an oven at 80℃ for 10 minutes, and then bake them at 150℃ for 30 minutes to thoroughly dry the topcoat. After passing the inspection, the copper parts are completed and the products are available. Figure 3 .

[0023] Embodiment 2: A method for preparing a cyan thermal coloration of a copper product surface comprises the following steps: (1) Pretreatment: Prepare copper products (brass cup holders), sandblast the surface of the copper parts to remove the surface oxide layer and oil stains, then further polish and clean them with a scouring pad in water, then rinse with clean water and blow dry; Prepare copper blackening agent solution: mix copper blackening agent (Q / YS.108 (Yishun brand)) and water in a mass ratio of 1:4; immerse the copper piece in the copper blackening agent solution for 5 seconds, then rinse it with clean water and immerse it in the copper blackening agent solution again for 5 seconds, finally rinse it and dry it for use; (2) Prepare white primer: 13 g / L bismuth nitrate, 1.5 g / L copper nitrate, 1 g / L copper sulfate, 1 g / L nickel sulfate, 10 ml / L 5% nitric acid, 25 ml / L ethylene glycol, 15 g / L titanium dioxide, and the balance water; Prepare blue reagent: bismuth nitrate 13g / L, copper nitrate 1.5g / L, copper sulfate 1g / L, nickel sulfate 1g / L, 5% nitric acid 10ml / L, ethylene glycol 25ml / L, phthalocyanine blue 10g / L, balance water; Prepare green reagent: bismuth nitrate 13g / L, copper nitrate 1.5g / L, copper sulfate 1g / L, nickel sulfate 1g / L, 5% nitric acid 10ml / L, ethylene glycol 25ml / L, cobalt green 10g / L, balance water; (3) Surface coloring: Place the copper piece treated in step (1) in a 120°C oven for preheating for 5 minutes, take it out and use a heat gun to maintain its surface temperature at 70°C; Use a spray pot to spray the white agent on the surface of the copper piece in a mist form and dry it with a hot air gun. Repeat several times (about 90 times) until a uniform white base layer appears on the surface of the copper piece. Use a spray pot to spray the blue and green agents alternately on the white base layer in a mist form and dry it with a hot air gun. Repeat this process several times (about 90 times) until a uniform gradient blue-green coloring layer appears on the surface of the copper piece. (4) Post-treatment: After drying the colored copper parts, cool them to room temperature, spray the varnish primer at 50℃, preheat them in an oven at 80℃ for 10 minutes, and then bake them at 150℃ for 30 minutes to thoroughly dry the primer. Then, after the temperature drops to room temperature, use fine sandpaper to gently polish the surface until it is smooth, spray the varnish topcoat, preheat them in an oven at 80℃ for 10 minutes, and then bake them at 150℃ for 30 minutes to thoroughly dry the topcoat. After passing the inspection, the copper parts are completed and the products are available. Figure 4 .

[0024] Example 3 A method for preparing a cyan thermal coloration of a copper product surface comprises the following steps: (1) Pretreatment: Prepare copper products (red copper kettles) and perform chemical pickling on the surface of the copper parts: soak in chemical pickling solution at room temperature for 5 minutes. The chemical pickling solution formula is: 100 mL / L of 98% concentrated sulfuric acid, 50 mL / L of 36% concentrated hydrochloric acid, 6 g / L of urea, 0.8 mL / L of OP-10 emulsifier, and the rest of water to remove the surface oxide layer and oil stains, then use a scouring pad to further polish and clean in water, then rinse with clean water and blow dry; Prepare copper blackening agent solution: mix copper blackening agent (Q / YS.108 (Yishun brand)) and water in a mass ratio of 1:2; immerse the copper piece in the copper blackening agent solution for 2 seconds, then rinse it with clean water and immerse it again in the copper blackening agent solution for 3 seconds, finally rinse it and dry it for use; (2) Prepare white primer: 12 g / L bismuth nitrate, 0.3 g / L copper nitrate, 0.3 g / L copper sulfate, 0.4 g / L nickel sulfate, 20 ml / L 5% nitric acid, 20 ml / L ethylene glycol, 10 g / L titanium dioxide, and the balance water; Prepare blue reagent: bismuth nitrate 12g / L, copper nitrate 0.3g / L, copper sulfate 0.3g / L, nickel sulfate 0.4g / L, 5% nitric acid 20ml / L, ethylene glycol 20ml / L, phthalocyanine blue 15g / L, balance water; Prepare green reagent: bismuth nitrate 12g / L, copper nitrate 0.3g / L, copper sulfate 0.3g / L, nickel sulfate 0.4g / L, 5% nitric acid 20ml / L, ethylene glycol 20ml / L, cobalt green 15g / L, balance water; (3) Surface coloring: Place the copper piece treated in step (1) in a 120°C oven for preheating for 8 minutes, take it out and use a hot air gun to maintain its surface temperature at 100°C; Use a spray pot to spray the white agent on the surface of the copper piece in a mist form and dry it with a hot air gun. Repeat this process several times (about 95 times) until a uniform white base layer appears on the surface of the copper piece. Use a spray pot to spray the blue and green agents alternately on the white base layer in a mist form, and dry them with a hot air gun. Repeat this process several times (about 100 times) until a uniform gradient blue-green coloring layer appears on the surface of the copper piece. (4) Post-processing: After drying the colored copper parts, cool them to room temperature, spray varnish primer at 50°C, preheat them in an oven at 80°C for 10 minutes, and then bake them at 150°C for 30 minutes to thoroughly dry the primer. Then, after the temperature drops to room temperature, use fine sandpaper to gently polish the surface until it is smooth, spray varnish topcoat, preheat them in an oven at 80°C for 10 minutes, and then bake them at 150°C for 30 minutes to thoroughly dry the topcoat. After passing the inspection, the copper parts are completed.

[0025] Example 4 A method for preparing a cyan thermal coloration of a copper product surface comprises the following steps: (1) Pretreatment: Prepare copper products (red copper kettles) and perform chemical pickling on the surface of the copper parts: soak in chemical pickling solution at room temperature for 3 minutes. The chemical pickling solution formula is: 120 mL / L of 98% concentrated sulfuric acid, 30 mL / L of 36% concentrated hydrochloric acid, 9 g / L of urea, 1.2 mL / L of OP-10 emulsifier, and the rest of water to remove the surface oxide layer and oil stains, then use a scouring pad to further polish and clean in water, then rinse with clean water and blow dry; Prepare copper blackening agent solution: mix copper blackening agent (Q / YS.108 (Yishun brand)) and water in a mass ratio of 1:3; immerse the copper piece in the copper blackening agent solution for 3 seconds, then rinse it with clean water and immerse it again in the copper blackening agent solution for 4 seconds, finally rinse it and dry it for use; Bismuth nitrate 12-20g / L, copper nitrate 0.3-2g / L, copper sulfate 0.3-3g / L, nickel sulfate 0.4-3g / L, nitric acid 5-20ml / L, ethylene glycol 20-50ml / L, (2) Prepare white primer: 20 g / L bismuth nitrate, 2 g / L copper nitrate, 3 g / L copper sulfate, 3 g / L nickel sulfate, 5 ml / L 10% nitric acid, 50 ml / L ethylene glycol, 30 g / L titanium dioxide, and the balance water; Prepare blue reagent: bismuth nitrate 20g / L, copper nitrate 2g / L, copper sulfate 3g / L, nickel sulfate 3g / L, 10% nitric acid 5ml / L, ethylene glycol 50ml / L, phthalocyanine blue 8g / L, balance water; Prepare green reagent: bismuth nitrate 20g / L, copper nitrate 2g / L, copper sulfate 3g / L, nickel sulfate 3g / L, 10% nitric acid 5ml / L, ethylene glycol 50ml / L, cobalt green 8g / L, balance water; (3) Surface coloring: Place the copper piece treated in step (1) in a 120°C oven for preheating for 8 minutes, take it out and use a hot air gun to maintain its surface temperature at 100°C; Use a spray pot to spray the white agent on the surface of the copper piece in a mist form and dry it with a hot air gun. Repeat this process several times (about 95 times) until a uniform white base layer appears on the surface of the copper piece. Use a spray pot to spray the blue and green agents alternately on the white base layer in a mist form, and dry them with a hot air gun. Repeat this process several times (about 100 times) until a uniform gradient blue-green coloring layer appears on the surface of the copper piece. (4) Post-processing: After drying the colored copper parts, cool them to room temperature, spray varnish primer at 50°C, preheat them in an oven at 80°C for 10 minutes, and then bake them at 150°C for 30 minutes to thoroughly dry the primer. Then, after the temperature drops to room temperature, use fine sandpaper to gently polish the surface until it is smooth, spray varnish topcoat, preheat them in an oven at 80°C for 10 minutes, and then bake them at 150°C for 30 minutes to thoroughly dry the topcoat. After passing the inspection, the copper parts are completed.

[0026] The test samples of the following test examples are 200 mm long*30 mm wide*1.2 mm thick.

[0027] Test Example 1 (Blank Control) The brass test piece was processed by the process of Example 2. To replace the medicine: White reagent: titanium dioxide 15g / L, balance water; Blue reagent: phthalocyanine blue 10g / L, balance water; Green reagent: cobalt green 10g / L, balance water; As a blank control.

[0028] Test Example 2 (Bismuth Mononitrate) The brass test piece was processed by the process of Example 2. To replace the medicine: White reagent: bismuth nitrate 15g / L, titanium dioxide 15g / L, balance water; Blue reagent: bismuth nitrate 15g / L, phthalocyanine blue 10g / L, balance water; Green reagent: bismuth nitrate 15g / L, cobalt green 10g / L, balance water; For comparison 1.

[0029] Test Example 3 (Bismuth Nitrate + Ethylene Glycol) The brass test piece was processed by the process of Example 2. To replace the medicine: White reagent: bismuth nitrate 15g / L, ethylene glycol 35ml / L, titanium dioxide 15g / L, balance water; Blue reagent: bismuth nitrate 15g / L, ethylene glycol 35ml / L, phthalocyanine blue 10g / L, balance water; Green reagent: bismuth nitrate 15g / L, ethylene glycol 35ml / L, cobalt green 10g / L, balance water; As a comparison 2.

[0030] Test Example 4 (Bismuth nitrate + nitric acid + ethylene glycol) The brass test piece was processed by the process of Example 2. To replace the medicine: White reagent: bismuth nitrate 15g / L, 5% nitric acid 10ml / L, ethylene glycol 35ml / L, titanium dioxide 15g / L, balance water; Blue reagent: bismuth nitrate 15g / L, 5% nitric acid 10ml / L, ethylene glycol 35ml / L, phthalocyanine blue 10g / L, balance water; Green reagent: bismuth nitrate 15g / L, 5% nitric acid 10ml / L, ethylene glycol 35ml / L, cobalt green 10g / L, balance water; For comparison 3.

[0031] The processed products of Test Examples 1 to 4 were subjected to adhesion tests. The results are shown in Figure 1 The adhesion level of the blank control is 5, the adhesion level of comparison 1 is 3, the adhesion level of comparison 2 is 2, and the adhesion level of comparison 3 is 1. The comparison shows that bismuth nitrate combined with ethylene glycol and nitric acid can effectively prevent the hydrolysis of bismuth nitrate, and significantly increase the adhesion between the copper substrate and the oxide film.

[0032] Test Example 5 (Present invention) The brass test piece processed by the process of Example 2 is used as a representative of the processing of the process of the present invention.

[0033] Oxide film mechanical properties test: .

[0034] Test Example 6 (Lack of nitric acid) The brass test piece was processed by the process of Example 2. To replace the medicine: White reagent: bismuth nitrate 15g / L, copper nitrate 1g / L, copper sulfate 1.5g / L, nickel sulfate 1.5g / L, ethylene glycol 35ml / L, titanium dioxide 15g / L, balance water; Blue reagent: bismuth nitrate 15g / L, copper nitrate 1g / L, copper sulfate 1.5g / L, nickel sulfate 1.5g / L, ethylene glycol 35ml / L, phthalocyanine blue 10g / L, balance water; Green reagent: bismuth nitrate 15g / L, copper nitrate 1g / L, copper sulfate 1.5g / L, nickel sulfate 1.5g / L, ethylene glycol 35ml / L, cobalt green 10g / L, balance water.

[0035] Test Example 7 (Copper nitrate + copper sulfate + nickel sulfate) The brass test piece was processed by the process of Example 2. To replace the medicine: White reagent: copper nitrate 1g / L, copper sulfate 1.5g / L, nickel sulfate 1.5g / L, titanium dioxide 15g / L, balance water; Blue reagent: copper nitrate 1g / L, copper sulfate 1.5g / L, nickel sulfate 1.5g / L, phthalocyanine blue 10g / L, balance water; Green reagent: copper nitrate 1g / L, copper sulfate 1.5g / L, nickel sulfate 1.5g / L, cobalt green 10g / L, balance water.

[0036] Test Example 8 (Copper mononitrate) The brass test piece was processed by the process of Example 2. To replace the medicine: White reagent: copper nitrate 1g / L, titanium dioxide 15g / L, balance water; Blue reagent: copper nitrate 1g / L, phthalocyanine blue 10g / L, balance water; Green reagent: copper nitrate 1g / L, cobalt green 10g / L, balance water.

[0037] The processed products of Test Examples 5 to 8 were compared in color. Figure 2 As shown, the color produced by the process of the present invention is uniform, bright, saturated, and has good color development. However, the non-fully compounded formulas all have different degrees of dull color or uneven coloring, poor color development, and general saturation; lack of nitric acid will reduce the coloring effect; copper ions and nickel ions have a continuous corrosion reaction on copper and a slight color change reaction on the coloring pigment. Therefore, the coloring formula of copper nitrate, copper sulfate, and nickel sulfate compounded has an adverse effect on the color performance and color development performance of the coloring layer.

[0038] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A method for preparing a blue-green thermal coloration of a copper product surface, characterized in that: The steps include: (1) Pretreatment: Prepare copper products, sandblast or chemically pickle the surface of the copper parts to remove the surface oxide layer and oil stains, then further polish and clean them with a scouring pad in water, then rinse with clean water and blow dry; prepare a copper blackening agent solution, immerse the copper parts in the copper blackening agent solution for 2 to 5 seconds, then rinse with clean water and immerse again in the copper blackening agent solution for 3 to 5 seconds, finally rinse and dry for use; (2) Prepare white reagent for base coating, and blue and green reagents for coloring; (3) Surface coloring: Place the copper piece treated in step (1) in a 120°C oven for preheating for 5-10 minutes, take it out and use a heat gun to maintain its surface temperature at 70-120°C; Use a spray pot to spray the white agent on the surface of the copper piece in a mist form and dry it with a hot air gun. Repeat this process several times until a uniform white base layer appears on the surface of the copper piece. Use a spray pot to spray the blue and green agents alternately on the white base layer in a mist form and dry them with a hot air gun. Repeat this process several times until a uniform gradient blue-green coloring layer appears on the surface of the copper piece. (4) Post-processing: Dry the colored copper parts and cool them to room temperature, spray varnish to seal the surface, and inspect them after drying.

2. The method for preparing a cyan thermal coloration of a copper product surface according to claim 1, characterized in that: The white agent formula is: 12-20 g / L bismuth nitrate, 0.3-2 g / L copper nitrate, 0.3-3 g / L copper sulfate, 0.4-3 g / L nickel sulfate, 5-20 ml / L nitric acid, 20-50 ml / L ethylene glycol, 10-30 g / L titanium dioxide, and the balance water.

3. The method for preparing a cyan thermal coloration of a copper product surface according to claim 1, characterized in that: The blue agent formula is: 12-20 g / L bismuth nitrate, 0.3-2 g / L copper nitrate, 0.3-3 g / L copper sulfate, 0.4-3 g / L nickel sulfate, 5-20 ml / L nitric acid, 20-50 ml / L ethylene glycol, 8-15 g / L phthalocyanine blue, and the balance water.

4. The method for preparing a cyan thermal coloration of a copper product surface according to claim 1, characterized in that: The green agent formula is: 12-20 g / L bismuth nitrate, 0.3-2 g / L copper nitrate, 0.3-3 g / L copper sulfate, 0.4-3 g / L nickel sulfate, 5-20 ml / L nitric acid, 20-50 ml / L ethylene glycol, 8-15 g / L cobalt green, and the balance water.

5. The method for preparing a cyan thermal coloration of a copper product surface according to claim 2, 3 or 4, characterized in that: The mass concentration of the nitric acid is 5-10%.

6. The method for preparing a cyan thermal coloration of a copper product surface according to claim 1, characterized in that: In step (1), the copper blackening agent solution is prepared by mixing the copper blackening agent and water in a mass ratio of 1:2-4.

7. The method for preparing a cyan thermal coloration of a copper product surface according to claim 1, characterized in that: In step (1), the formula of the chemical pickling solution for the chemical pickling treatment is: 100 ~ 120 mL / L of concentrated sulfuric acid, 30 ~ 50 mL / L of concentrated hydrochloric acid, 6 ~ 9 g / L of urea, 0.8 ~ 1.2 mL / L of OP-10 emulsifier, and the balance of water.

8. The method for preparing a cyan thermal coloration of a copper product surface according to claim 7, characterized in that: The mass concentration of concentrated sulfuric acid is 98%, and the mass concentration of concentrated hydrochloric acid is 36%.

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