CN102091686B - Spraying method - Google Patents

Abstract

A method of spray coating comprising the steps of: providing a workpiece, wherein the workpiece is provided with a surface to be sprayed; spraying, namely spraying a liquid coating with the viscosity of 1 cP-8 cP on the surface of a workpiece; pre-baking at high temperature, namely baking the workpiece for 10 to 90 seconds at the temperature of 50 to 80 ℃; pre-baking at a low temperature, namely baking the workpiece for 1 to 4 minutes at a temperature of between 30 and 50 ℃, wherein the gradient of the sprayed surface of the workpiece is within 20 ℃ in the baking process; and drying at a high temperature, and baking the workpiece for 5 to 15 minutes at a temperature of between 50 and 80 ℃. The three steps of high-temperature pre-baking, low-temperature pre-baking and high-temperature drying are matched to enable the sprayed film to have uniform thickness and be difficult to form defects such as pinholes, the inclination of the workpiece can be within the range of twenty degrees when the film is pre-baked at low temperature, the workpiece can be placed at a larger inclination angle when the film is dried at high temperature, the utilization rate of baking equipment is improved, and the baking cost is reduced.

Description

Spraying method

technical field

The invention relates to a spraying method.

Background technique

The casings of general consumer electronic products, such as mobile phones or computers, are usually painted to achieve the decorative purpose of beautifying the casings. When spraying, paint or ink is sprayed on the surface of the workpiece, and a coating film is formed after the solvent evaporates. When the workpiece is dried, it is necessary to keep the sprayed surface roughly horizontal to prevent the upper coating film from moving downward when it is placed obliquely, so that the lower edge of the coating film will be thicker. Less, higher baking cost.

Contents of the invention

In view of the above situation, it is necessary to provide a spraying method with lower baking cost.

A spraying method, comprising the following steps:

providing a workpiece, the workpiece has a surface to be sprayed;

Spraying, spraying liquid paint with a viscosity of 1cP to 8cP onto the surface of the workpiece;

High-temperature pre-baking, place the workpiece at a temperature of 50°C to 80°C and bake for 10 seconds to 90 seconds;

Low-temperature pre-baking, place the workpiece at a temperature of 30°C to 50°C and bake for 1 minute to 4 minutes. During the baking process, the inclination of the sprayed surface of the workpiece is within 20 degrees;

High-temperature drying, the workpiece is baked at a temperature of 50°C to 80°C for 5 minutes to 15 minutes.

High-temperature pre-baking can quickly remove part of the solvent in the sprayed liquid coating and reduce the fluidity of the coating film. The high temperature pre-baking time is short, which can prevent the solvent in the coating film from reacting with the surface of the workpiece at high temperature and corrode the workpiece. Low temperature pre-baking can slowly remove part of the solvent in the sprayed liquid paint. The coating film has a certain fluidity during low-temperature pre-baking, and the volatilization rate of the solvent is small, so that after the solvent volatilizes, the coating film can flow into the cavity formed by the volatilization of the solvent, thereby avoiding excessive solvent evaporation during baking. Fast and the formation of pinholes and other defects. High-temperature drying can completely remove the solvent in the coating film so that the coating film on the surface of the workpiece is completely dry. The three steps of high-temperature pre-baking, low-temperature pre-baking and high-temperature drying make the thickness of the sprayed coating uniform and not easy to form defects such as pinholes. At the same time, high-temperature pre-baking reduces the fluidity of the coating film, so that it can be carried out within the range of workpiece inclination less than 20 degrees during low-temperature pre-baking, and the workpiece can be placed at a larger inclination angle during high-temperature drying, thereby improving The utilization rate of baking equipment reduces the cost of baking.

Detailed ways

The spraying method of the present invention will be further described in detail below in conjunction with the embodiments.

Embodiment one: a kind of spraying method, comprises the following steps:

In step 1, a workpiece is provided, and the workpiece has a surface to be sprayed.

Step 2, spraying, spraying a liquid paint with a viscosity of 1 cP onto the surface of the workpiece to be sprayed to form a coating film with a thickness of 5 μm-60 μm. In this embodiment, the liquid coating is an acrylic coating, and the solvent of the liquid coating is tetrahydrofuran, acetone, methyl acetate, ethyl acetate, butanone, isopropyl acetate, methyl n-acetone, n-propyl acetate, methyl isobutyl methyl ketone (MIBK), isobutyl acetate, 2-nitropropane, n-butyl acetate, propylene glycol methyl ether, methyl isoamyl ketone (MIAK), methyl amyl acetate, n-butyl propionate, propylene glycol methyl Ether acetate, amyl acetate, methyl n-amyl ketone, isobutyl isobutyrate, hydroxyethyl ethyl ether, cyclohexanone, propylene glycol monobutyl ether, propylene glycol monopropyl ether, ethylene glycol ethyl ether Ester, diisobutyl ketone (DIBK), ethylene glycol propyl ether, diacetone alcohol, ethylene glycol butyl ether, propylene glycol butyl ether, 2-ethylhexyl formate, ethylene glycol butyl ether acetate, diacetone alcohol Propylene glycol methyl ether, diethylene glycol diacetate, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol propyl ether, ethylene glycol hexyl ether, diethylene glycol ethyl ether acetate, diethylene glycol Butyl ether, ethylene glycol-2-ethylhexyl ether, diethylene glycol butyl ether acetate, propylene glycol monophenyl ether, methanol, ethanol, isopropanol, n-propanol, 2-butanol, isobutyl Alcohol, n-butanol, methyl isobutyl carbinol, pentanol, cyclohexanol, methylene chloride, perchloroethylene, toluene, naphtha, xylene or a mixture of several. The percentage of solid mass in the liquid coating to the total mass of the coating is 10%.

Step 3, high-temperature pre-baking, place the workpiece in an oven at a temperature of 50°C and bake for 90 seconds. During the baking process, the projected area of the sprayed surface of the workpiece on a plane perpendicular to the direction of gravity is maximized. High-temperature pre-baking can quickly remove part of the solvent in the liquid coating and reduce the fluidity of the coating film.

Step 4, low-temperature pre-baking, the workpiece is taken out of the oven at 50°C and placed in an oven at 30°C for 4 minutes, and the inclination of the sprayed surface of the workpiece during the baking process is within 20 degrees. Low temperature pre-baking can slowly remove part of the solvent in the sprayed liquid paint. The coating film has a certain fluidity during pre-baking at low temperature, and the volatilization rate of the solvent is small, so that after the solvent volatilizes, the coating film can flow into the cavity formed by the volatilization of the solvent, thereby avoiding the formation of needles in the coating film during baking. holes etc.

Step 5, high-temperature drying, the workpiece is taken out from the oven at 30°C and placed in an oven at 50°C for 15 minutes. The coating film on the surface of the workpiece treated in step 4 has been cured, but there is still a small amount of solvent in the coating film. At this time, the coating film is soft, poor in performance and inconvenient to store. High temperature drying can completely remove the solvent in the coating film Let the coating film on the surface of the workpiece dry completely.

The coating film is pre-baked at high temperature, pre-baked at low temperature and dried at high temperature to remove the solvent in the coating film. High-temperature pre-baking can quickly remove part of the solvent in the liquid coating and reduce the fluidity of the coating film. At the same time, the high-temperature pre-baking time is short, which can prevent the solvent in the coating film from reacting with the surface of the workpiece at high temperature and corrode the workpiece; the low-temperature pre-baking can slowly remove the solvent when the coating film has a certain fluidity, which can prevent the solvent from Defects such as pinholes will be formed if volatilization is too fast; the solvent in the coating film will be completely removed by high-temperature drying to completely dry the coating film on the surface of the workpiece. After high-temperature pre-baking, the fluidity of the coating film is reduced. At this time, when the workpiece is placed at an inclination, the upper coating film is not easily affected by gravity and flows downward, so that the inclination of the workpiece during low-temperature pre-baking is within the range of less than 20 degrees. It can be carried out, and the workpiece can be placed at a greater inclination angle during high-temperature drying, thereby improving the utilization rate of the baking equipment and reducing the cost of baking.

Further, after step 2, the workpiece can be placed at a temperature of 25° C. for 30 seconds to level the liquid paint on the surface of the workpiece. At this time, the sprayed surface of the workpiece should be roughly level. When the liquid coating used is an ultraviolet curing coating, after step five, the workpiece can also be cured by ultraviolet light so that the solid in the liquid coating undergoes a chemical reaction to be cured.

Embodiment two: a kind of spraying method, comprises the following steps:

In step 1, a workpiece is provided, and the workpiece has a surface to be sprayed.

Step 2, spraying, spraying a liquid paint with a viscosity of 8 cP onto the surface of the workpiece to be sprayed to form a coating film with a thickness of 5 μm-60 μm. In this embodiment, the liquid coating is an acrylic coating, and the solvent of the liquid coating is tetrahydrofuran, acetone, methyl acetate, ethyl acetate, butanone, isopropyl acetate, methyl n-acetone, n-propyl acetate, methyl isobutyl methyl ketone (MIBK), isobutyl acetate, 2-nitropropane, n-butyl acetate, propylene glycol methyl ether, methyl isoamyl ketone (MIAK), methyl amyl acetate, n-butyl propionate, propylene glycol methyl Ether acetate, amyl acetate, methyl n-amyl ketone, isobutyl isobutyrate, hydroxyethyl ethyl ether, cyclohexanone, propylene glycol monobutyl ether, propylene glycol monopropyl ether, ethylene glycol ethyl ether Ester, diisobutyl ketone (DIBK), ethylene glycol propyl ether, diacetone alcohol, ethylene glycol butyl ether, propylene glycol butyl ether, 2-ethylhexyl formate, ethylene glycol butyl ether acetate, diacetone alcohol Propylene glycol methyl ether, diethylene glycol diacetate, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol propyl ether, ethylene glycol hexyl ether, diethylene glycol ethyl ether acetate, diethylene glycol Butyl ether, ethylene glycol-2-ethylhexyl ether, diethylene glycol butyl ether acetate, propylene glycol monophenyl ether, methanol, ethanol, isopropanol, n-propanol, 2-butanol, isobutyl Alcohol, n-butanol, methyl isobutyl carbinol, pentanol, cyclohexanol, methylene chloride, perchloroethylene, toluene, naphtha, xylene or a mixture of several. The percentage of solid mass in the liquid coating to the total mass of the coating is 50%.

Step 3, high-temperature pre-baking, place the workpiece in an oven with a temperature of 80°C and bake for 10 seconds. During the baking process, the projected area of the sprayed surface of the workpiece on a plane perpendicular to the direction of gravity reaches the maximum projected area. 0.966 times.

Step 4, low-temperature pre-baking, take the workpiece out of the oven at 80°C and place it in an oven at 50°C to bake for 1 minute. During the baking process, the inclination of the sprayed surface of the workpiece is within 15 degrees.

Step 5, high-temperature drying, the workpiece is taken out from the oven at 50°C and placed in an oven at 80°C for 5 minutes.

Further, after step 2, the workpiece can be placed at a temperature of 30° C. for 30 seconds to level the liquid paint on the surface of the workpiece. At this time, the sprayed surface of the workpiece should be roughly level. When the liquid coating used is an ultraviolet curing coating, after step five, the workpiece can also be cured by ultraviolet light so that the solid in the liquid coating undergoes a chemical reaction to be cured.

Embodiment three: a kind of spraying method, comprises the following steps:

In step 1, a workpiece is provided, and the workpiece has a surface to be sprayed.

Step 2, spraying, spraying a liquid paint with a viscosity of 4 cP onto the surface of the workpiece to be sprayed to form a coating film with a thickness of 5 μm-60 μm. In this embodiment, the liquid coating is an acrylic coating, and the solvent of the liquid coating is tetrahydrofuran, acetone, methyl acetate, ethyl acetate, butanone, isopropyl acetate, methyl n-acetone, n-propyl acetate, methyl isobutyl methyl ketone (MIBK), isobutyl acetate, 2-nitropropane, n-butyl acetate, propylene glycol methyl ether, methyl isoamyl ketone (MIAK), methyl amyl acetate, n-butyl propionate, propylene glycol methyl Ether acetate, amyl acetate, methyl n-amyl ketone, isobutyl isobutyrate, hydroxyethyl ethyl ether, cyclohexanone, propylene glycol monobutyl ether, propylene glycol monopropyl ether, ethylene glycol ethyl ether Ester, diisobutyl ketone (DIBK), ethylene glycol propyl ether, diacetone alcohol, ethylene glycol butyl ether, propylene glycol butyl ether, 2-ethylhexyl formate, ethylene glycol butyl ether acetate, diacetone alcohol Propylene glycol methyl ether, diethylene glycol diacetate, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol propyl ether, ethylene glycol hexyl ether, diethylene glycol ethyl ether acetate, diethylene glycol Butyl ether, ethylene glycol-2-ethylhexyl ether, diethylene glycol butyl ether acetate, propylene glycol monophenyl ether, methanol, ethanol, isopropanol, n-propanol, 2-butanol, isobutyl Alcohol, n-butanol, methyl isobutyl carbinol, pentanol, cyclohexanol, methylene chloride, perchloroethylene, toluene, naphtha, xylene or a mixture of several. The percentage of solid mass in the liquid coating to the total mass of the coating is 30%.

Step 3, high-temperature pre-baking, place the workpiece in an oven at a temperature of 70°C and bake for 30 seconds. During the baking process, the projected area of the sprayed surface of the workpiece on a plane perpendicular to the direction of gravity is maximized.

Step 4, low-temperature pre-baking, take the workpiece out of the oven at 70°C and place it in an oven at 45°C to bake for 3 minutes. During the baking process, the inclination of the sprayed surface of the workpiece is within 20°.

Step five, high temperature drying, the workpiece is taken out from the oven at 45°C and placed in an oven at 70°C for 8 minutes.

Further, after step 2, the workpiece can be placed at a temperature of 20° C. for 60 seconds to level the liquid paint on the surface of the workpiece. At this time, the sprayed surface of the workpiece should be roughly level. When the liquid coating used is an ultraviolet curing coating, after step five, the workpiece can also be cured by ultraviolet light so that the solid in the liquid coating undergoes a chemical reaction to be cured.

Embodiment four: a kind of spraying method, comprises the following steps:

In step 1, a workpiece is provided, and the workpiece has a surface to be sprayed.

Step 2, spraying, spraying a liquid paint with a viscosity of 6 cP onto the surface of the workpiece to be sprayed to form a coating film with a thickness of 5 μm-60 μm. In this embodiment, the liquid coating is an acrylic coating, and the solvent of the liquid coating is tetrahydrofuran, acetone, methyl acetate, ethyl acetate, butanone, isopropyl acetate, methyl n-acetone, n-propyl acetate, methyl isobutyl methyl ketone (MIBK), isobutyl acetate, 2-nitropropane, n-butyl acetate, propylene glycol methyl ether, methyl isoamyl ketone (MIAK), methyl amyl acetate, n-butyl propionate, propylene glycol methyl Ether acetate, amyl acetate, methyl n-amyl ketone, isobutyl isobutyrate, hydroxyethyl ethyl ether, cyclohexanone, propylene glycol monobutyl ether, propylene glycol monopropyl ether, ethylene glycol ethyl ether Ester, diisobutyl ketone (DIBK), ethylene glycol propyl ether, diacetone alcohol, ethylene glycol butyl ether, propylene glycol butyl ether, 2-ethylhexyl formate, ethylene glycol butyl ether acetate, diacetone alcohol Propylene glycol methyl ether, diethylene glycol diacetate, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol propyl ether, ethylene glycol hexyl ether, diethylene glycol ethyl ether acetate, diethylene glycol Butyl ether, ethylene glycol-2-ethylhexyl ether, diethylene glycol butyl ether acetate, propylene glycol monophenyl ether, methanol, ethanol, isopropanol, n-propanol, 2-butanol, isobutyl Alcohol, n-butanol, methyl isobutyl carbinol, pentanol, cyclohexanol, methylene chloride, perchloroethylene, toluene, naphtha, xylene or a mixture of several. The percentage of solid mass in the liquid coating to the total mass of the coating is 40%.

Step 3, high-temperature pre-baking, place the workpiece in an oven at a temperature of 70°C and bake for 30 seconds. During the baking process, the projected area of the sprayed surface of the workpiece on a plane perpendicular to the direction of gravity is maximized.

Step 4, low-temperature pre-baking, take the workpiece out of the oven at 70°C and place it in an oven at 45°C to bake for 3 minutes. During the baking process, the inclination of the sprayed surface of the workpiece is within 20°.

Step five, high temperature drying, the workpiece is taken out from the oven at 45°C and placed in an oven at 70°C for 12 minutes.

Further, after step 2, the workpiece can be placed at a temperature of 25° C. for 30 seconds to level the liquid paint on the surface of the workpiece. At this time, the sprayed surface of the workpiece should be roughly level. When the liquid coating used is an ultraviolet curing coating, after step five, the workpiece can also be cured by ultraviolet light so that the solid in the liquid coating undergoes a chemical reaction to be cured.

Claims (10)

1. A spraying method, comprising the following steps: providing a workpiece, the workpiece has a surface to be sprayed; Spraying, spraying liquid paint with a viscosity of 1cP to 8cP onto the surface of the workpiece; High-temperature pre-baking, place the workpiece at a temperature of 50°C to 80°C and bake for 10 seconds to 90 seconds; Low-temperature pre-baking, place the workpiece at a temperature of 30°C to 50°C and bake for 1 minute to 4 minutes. During the baking process, the inclination of the sprayed surface of the workpiece is within 20 degrees; High-temperature drying, the workpiece is baked at a temperature of 50°C to 80°C for 5 minutes to 15 minutes. 2. The spraying method according to claim 1, characterized in that: during high-temperature pre-baking, the workpiece is baked at a temperature of 70°C for 30 seconds, and during the baking process, the sprayed surface of the workpiece is placed perpendicular to gravity The projected area on the plane of the direction of action is between the maximum and the maximum of 0.966 times. 3. The spraying method according to claim 1, characterized in that: during low-temperature pre-baking, the workpiece is baked at a temperature of 45° C. for 3 minutes. 4. The spraying method according to claim 1, characterized in that: when drying at a high temperature, the workpiece is baked at a temperature of 70° C. for 8 minutes to 12 minutes. 5 . The spraying method according to claim 1 , wherein the workpiece is placed at a temperature of 20° C. to 30° C. for 30-60 seconds before the high-temperature pre-baking. 6. The spraying method according to claim 1, characterized in that: the thickness of the coating formed by spraying the liquid paint on the workpiece is 5 μm-60 μm. 7. The spraying method according to claim 1, characterized in that: said liquid paint is acrylic paint. 8. The spraying method according to claim 1, characterized in that: the solvent in the liquid coating is tetrahydrofuran, acetone, methyl acetate, ethyl acetate, butanone, isopropyl acetate, methyl n-acetone, n- Propyl acetate, methyl isobutyl ketone (MIBK), isobutyl acetate, 2-nitropropane, n-butyl acetate, propylene glycol methyl ether, methyl isoamyl ketone (MIAK), methyl amyl acetate, n-butyl propionate, propylene glycol methyl ether acetate, amyl acetate, methyl n-amyl ketone, isobutyl isobutyrate, hydroxyethyl ethyl ether, cyclohexanone, propylene glycol monobutyl ether, propylene glycol monopropylene Base ether, ethylene glycol ethyl ether acetate, diisobutyl ketone (DIBK), ethylene glycol propyl ether, diacetone alcohol, ethylene glycol butyl ether, propylene glycol butyl ether, 2-ethylhexyl formate, ethylene glycol Alcohol butyl ether acetate, dipropylene glycol methyl ether, glycol diacetate, diethylene glycol methyl ether, diethylene glycol ethyl ether, diethylene glycol propyl ether, ethylene glycol hexyl ether, diethylene glycol ethyl ether Acetate, diethylene glycol butyl ether, ethylene glycol-2-ethylhexyl ether, diethylene glycol butyl ether acetate, propylene glycol monophenyl ether, methanol, ethanol, isopropanol, n-propanol , 2-butanol, isobutanol, n-butanol, methyl isobutyl carbinol, pentanol, cyclohexanol, methylene chloride, perchlorethylene, toluene, naphtha, xylene, one or more mixture of species. 9 . The spraying method according to claim 1 , wherein the percentage of solid mass of the liquid paint to the total mass of the paint before baking is 10% to 50%. 10. The spraying method according to claim 1, characterized in that: the liquid coating is an ultraviolet curing coating, and the coating film is cured by ultraviolet light after drying at high temperature.