Spraying method of high-hardness oil paint for aluminum alloy wheel

Abstract

The invention belongs to the technical field of coating, and relates to an aluminum alloy wheel high-hardness oil paint spraying method which comprises the following steps: pretreating a wheel blank to remove surface impurities; ash bottom powder is sprayed, the film thickness ranges from 60 micrometers to 120 micrometers, and ash is removed after grinding; high-hardness oil paint is sprayed, standing and leveling are conducted, the leveling time is 5-8 min, the thickness of a paint film is 10-25 microns, the high-hardness oil paint is filtered through a filter screen of 400 meshes or above, and spraying is conducted after standing is conducted till no bubbles exist; and natural surface drying or low-temperature drying is performed for 5 days or more, so that the paint coating is stable in thickness, and the hardness reaches 4H or more. According to the spraying method of the high-hardness oil paint for the aluminum alloy wheel, the existing equipment can be utilized, and if the paint is cured at normal temperature, the equipment investment is not increased; the hardness of the used high-hardness nano silicon resin is high and is greater than 4H, so that the anti-corrosion requirement in a severe environment is completely met; and the coating is convenient to clean, does not scratch, can be recoated for more than 5 times, and has the adhesive force of 0 level and no decline.

Description

Technical Field

[0001] The invention belongs to the technical field of coating, relates to the production of coated wheels, and in particular to a method for spraying high-hardness oil-based paint on aluminum alloy wheels. Background Art

[0002] The surface of a car needs to be protected and decorated by paint. The quality of the paint film is an intuitive evaluation of the quality of the car, which can directly affect the market competitiveness of the car. The development and changes of the automobile industry have put forward requirements for high quality, low cost and green technology for paint. In addition to requiring good surface quality and workability, paint for car wheels also needs to have different requirements according to different application fields. For example, some paints for car wheels require the coating film to have excellent mechanical properties, and the wheels for large machinery require the coating film to have excellent salt spray resistance and weather resistance. The requirements for paint spraying of car wheels are also different.

[0003] In the manufacturing process of aluminum alloy wheels, ordinary low-hardness paint is generally used for spraying, which has the following three disadvantages: 1. Low-hardness paint requires high-temperature curing, such as curing at 140℃ for 15 to 25 minutes, which requires a large amount of funds for the company to invest in curing equipment, increasing operating costs; 2. The coating hardness of low-hardness paint is generally only HB or H. Due to the narrow construction surface, the paint layer is often damaged, which causes wheel corrosion and affects safety performance; 3. Low-hardness paint has poor recoatability. Generally, the adhesion drops from level 0 to level 1 to 2 after 3 to 4 sprays. The organic coating formed after the current automobile wheel painting is mostly measured by the film hardness pencil method, which is generally HB or H. However, when the wheel is used in a harsh environment, the existing hardness cannot effectively protect it, resulting in the damage of the paint layer, which causes the wheel to corrode and affects safety performance.

[0004] With the continuous improvement of wheel anti-corrosion requirements in recent years, higher requirements have been put forward for the surface hardness of coatings. It is a general trend to replace existing low-hardness coatings with new high-hardness coatings. Nanomaterials have special functions such as UV resistance, anti-aging, high strength and toughness, good electrostatic shielding effect, color change effect, antibacterial and deodorizing. Using them in automotive paints can improve the traditional performance of the paint film and give it new functions. In recent years, the wide application of high-hardness nano-silicone resins in various industries has provided experience for its application in the wheel industry. Summary of the invention

[0005] Aiming at the problems existing in the use of common paint, the purpose of the present invention is to disclose a method for spraying high-hardness oil-based paint on aluminum alloy wheels.

[0006] Technical Solution

[0007] A method for spraying high-hardness oil-based paint on an aluminum alloy wheel comprises the following steps:

[0008] (1) The wheel blank is pre-treated to remove surface impurities;

[0009] (2) Spraying base powder, film thickness 60 ~ 120μm, and remove dust after grinding;

[0010] (3) Spray high-hardness oil-based paint and let it stand to level. The leveling time is 5 to 8 minutes and the paint film thickness is 10 to 25

[0011] μm, the high-hardness oily paint is filtered through a filter screen of 400 mesh or above, and sprayed after standing still without bubbles;

[0012] (4) Allow to dry naturally or dry at low temperature for 5 days or more to stabilize the thickness of the paint coating and achieve a hardness of 4H or above.

[0013] In a preferred disclosed example of the present invention, in step (1), the pretreatment is hot water washing → degreasing → water washing → acid washing → pure water washing → passivation → pure water washing → drying.

[0014] In a preferred disclosed example of the present invention, in step (2), the polishing is to remove the uneven base powder applied to the surface of the hub to cover the surface defects.

[0015] In the preferred disclosed example of the present invention, in step (3), the high-hardness oil-based paint refers to a high-hardness nano-silicone resin paint which is a self-crosslinking nano-coating with a fast surface drying speed at room temperature and is commercially available.

[0016] In the preferred disclosed example of the present invention, in step (3), the spray gun is kept 10 to 25 cm away from the construction surface during spraying, and the spraying pressure is adjusted as appropriate.

[0017] In the preferred disclosed example of the present invention, in step (4), the natural surface drying is to place the wheel in a room temperature environment for 24 hours or more, wherein the hardness reaches 4H after 24 hours and reaches 6H to 8H after 5 days.

[0018] In the preferred disclosed example of the present invention, in step (4), the low-temperature drying is carried out at 80-100°C for 20-30 minutes to achieve a hardness of 4H, and after being left for 5 days, the hardness reaches 6H-8H.

[0019] The hardness of existing wheel coatings is generally HB-H. When the wheels are used in harsh environments, the current hardness cannot effectively protect them, and the paint layer is often damaged, which causes wheel corrosion and affects safety performance. The use of high-hardness oil-based paint can increase the hardness to above 4H. In order to avoid uneven thickness due to high and low viscosity, use stock liquid spraying. Filter with a 400 mesh or above filter, let it stand for no bubbles, and then apply to ensure a uniform thickness of 10-25μm. A special oil-based paint spray gun is used for efficient spraying to avoid pollution and waste caused by large-scale spraying. To achieve the highest hardness and best performance of the coating, it needs to stand for more than 5 days.

[0020] High-hardness nano silicone resin paint is used on stone, plastic, fiberglass, metal, aluminum plate, aluminum alloy, glass, and can also be used as anti-graffiti paint, self-cleaning glass paint, photovoltaic glass, electroplating varnish and other fields. It has high gloss, high fullness, high hardness, high adhesion, high wear resistance, anti-fouling, anti-aging, anti-oxidation, anti-yellowing, anti-pollution, anti-solvent, acid, alkali, salt and washing resistance; it is odorless, environmentally friendly and cost-effective; it can be widely used in decorative parts of automobiles, high-speed railways, airplanes, mobile phones, etc.; especially the protective coating of aluminum alloy and stainless steel on car decorative strips, body paint, front face, wheel hub, seat frame and other parts.

[0021] Beneficial Effects

[0022] The spraying method of high-hardness oil-based paint for aluminum alloy wheels disclosed in the present invention can utilize existing equipment, and if cured at room temperature, the equipment investment will not be increased; since the hardness of the high-hardness nano-silicone resin used is high, greater than 4H, it fully meets the anti-corrosion requirements of harsh environments; it is easy to clean without scratches, can be re-coated more than 5 times, and the adhesion is level 0 without decline. DETAILED DESCRIPTION

[0023] The present invention is described in detail below in conjunction with the embodiments so that those skilled in the art can better understand the present invention, but the present invention is not limited to the following embodiments.

[0024] Example 1

[0025] A method for spraying high-hardness oil-based paint on an aluminum alloy wheel comprises the following steps:

[0026] (1) The wheel blank is washed with hot water → degreased → washed with water → pickled → washed with pure water → passivated → washed with pure water →

[0027] Drying to remove surface oil and dirt;

[0028] (2) Spraying base powder, film thickness 60 ~ 120μm, and remove dust after grinding;

[0029] (3) Spray high-hardness oil-based paint and let it stand to level. The leveling time is 5 to 8 minutes and the paint film thickness is 10 to 25

[0030] μm, the high-hardness oily paint is a high-hardness nano-silicone resin paint, which is filtered with a filter screen of 400 mesh or above, and sprayed after standing without bubbles;

[0031] (4) Allow to dry naturally for 5 days or more, so that the paint coating thickness is stable and the hardness reaches 4H or above.

[0032] Example 2

[0033] A method for spraying high-hardness oil-based paint on an aluminum alloy wheel comprises the following steps:

[0034] (1) The wheel blank is washed with hot water → degreased → washed with water → pickled → washed with pure water → passivated → washed with pure water →

[0035] Drying to remove surface oil and dirt;

[0036] (2) Spraying base powder, film thickness 60 ~ 120μm, and remove dust after grinding;

[0037] (3) Spray high-hardness oil-based paint and let it stand to level. The leveling time is 5 to 8 minutes and the paint film thickness is 10 to 25

[0038] μm, the high-hardness oily paint is a high-hardness nano-silicone resin paint, which is filtered with a filter screen of 400 mesh or above, and sprayed after standing without bubbles;

[0039] (4) Low temperature drying: bake at 80-100℃ for 20-30min to stabilize the thickness of the paint coating and achieve a hardness of 4H or above.

[0040] Example 3

[0041] A method for spraying high-hardness oil-based paint on an aluminum alloy wheel comprises the following steps:

[0042] (1) The wheel blank is washed with hot water → degreased → washed with water → pickled → washed with pure water → passivated → washed with pure water →

[0043] Drying to remove surface oil and dirt;

[0044] (2) Spraying base powder, film thickness 60 ~ 120μm, and remove dust after grinding;

[0045] (3) Spray high-hardness oil-based paint and let it stand to level. The leveling time is 5 to 8 minutes and the paint film thickness is 10 to 25

[0046] μm, the high-hardness oil-based paint is a high-hardness nano-silicone resin paint, which is filtered with a filter screen of 400 mesh or above, and sprayed after standing still without bubbles; during spraying, the spray gun is 10 to 25 cm away from the construction surface, and the spraying pressure is adjusted according to the situation;

[0047] (4) Allow to dry naturally for 5 days or more, so that the paint coating thickness is stable and the hardness reaches 4H or above.

[0048] Example 4

[0049] A method for spraying high-hardness oil-based paint on an aluminum alloy wheel comprises the following steps:

[0050] (1) The wheel blank is washed with hot water → degreased → washed with water → pickled → washed with pure water → passivated → washed with pure water →

[0051] Drying to remove surface oil and dirt;

[0052] (2) Spraying base powder, film thickness 60 ~ 120μm, and remove dust after grinding;

[0053] (3) Spray high-hardness oil-based paint and let it stand to level. The leveling time is 5 to 8 minutes and the paint film thickness is 10 to 25

[0054] μm, the high-hardness oil-based paint is a high-hardness nano-silicone resin paint, which is filtered with a filter screen of 400 mesh or above, and sprayed after standing still without bubbles; during spraying, the spray gun is 10 to 25 cm away from the construction surface, and the spraying pressure is adjusted according to the situation;

[0055] (4) Low temperature drying: bake at 80-100℃ for 20-30min to stabilize the thickness of the paint coating and achieve a hardness of 4H or above.

[0056] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the specification of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for spraying high-hardness oil-based paint on aluminum alloy wheels, characterized in that: The steps include: (1) The wheel blank is pre-treated to remove surface impurities; (2) Spraying base powder, film thickness 60-120 μm, and remove dust after grinding; (3) Spraying high-hardness oil-based paint, leaving it to level, the leveling time is 5 to 8 minutes, and the paint film thickness is 10 to 25 μm. The high-hardness oil-based paint is filtered with a filter screen of 400 mesh or above, and spraying is performed after leaving it to level without bubbles; (4) Allow the paint coating to dry naturally or dry at low temperature for 5 days or more, so that the thickness of the paint coating is stable and the hardness reaches 4H or above.

2. The method for spraying high-hardness oil-based paint for aluminum alloy wheels according to claim 1, characterized in that: In step (1), the pretreatment is hot water washing → degreasing → water washing → acid washing → pure water washing → passivation → pure water washing → drying.

3. The method for spraying high-hardness oil-based paint for aluminum alloy wheels according to claim 1, characterized in that: In step (2), the polishing is to remove the uneven base powder applied to the surface of the hub to cover the surface defects.

4. The method for spraying high-hardness oil-based paint for aluminum alloy wheels according to claim 1, characterized in that: In step (3), the high-hardness oil-based paint refers to a high-hardness nano-silicone resin paint which is a self-crosslinking nano-coating with a fast surface drying speed at room temperature.

5. The method for spraying high-hardness oil-based paint for aluminum alloy wheels according to claim 1, characterized in that: In step (3), the spray gun is kept 10 to 25 cm away from the construction surface during spraying, and the spraying pressure is adjusted as appropriate.

6. The method for spraying high-hardness oil-based paint for aluminum alloy wheels according to claim 1, characterized in that: In step (4), the natural surface drying is to place the wheel in a room temperature environment for 24 hours or more, wherein the hardness reaches 4H after 24 hours and reaches 6H to 8H after 5 days.

7. The method for spraying high-hardness oil-based paint for aluminum alloy wheels according to claim 1, characterized in that: In step (4), the low-temperature drying is carried out at 80-100°C for 20-30 minutes to achieve a hardness of 4H, and after being left for 5 days, the hardness reaches 6H-8H.