What are the differences between water - based paint spraying lines and oil - based paint spraying lines?

The differences between water - based paint spraying lines and oil - based paint spraying lines are mainly reflected in the following aspects:

1. Coating Characteristics

• Water - based Paint: It uses water as a diluent, has good environmental friendliness, low odor, and a low VOC (Volatile Organic Compounds) content, which is relatively friendly to the environment and human health. Its drying speed is greatly affected by environmental humidity and temperature. In high - humidity environments, the drying time may be prolonged.

• Oil - based Paint: It uses organic solvents such as xylene and toluene as diluents, has a strong odor, a high VOC content, and poses certain harm to the environment and human body. Its drying speed is relatively stable, less affected by the environment. Generally, the dried paint film has high hardness and good gloss.

2. Equipment Requirements

• Water - based Paint: Due to the high electrical conductivity of water - based paint, strict grounding requirements are imposed on the spraying equipment to prevent electrostatic accumulation. The equipment materials need to have good water - resistance and corrosion - resistance because water may corrode some metal materials. The viscosity of some water - based paints is relatively low, which may require a lower spraying pressure and a smaller spray gun nozzle diameter, generally between 0.8 - 1.5mm.

• Oil - based Paint: The grounding requirements for the equipment are relatively low, but good ventilation equipment is needed to exhaust the volatile gases of organic solvents. The equipment materials generally require good solvent - resistance. The viscosity of oil - based paint is relatively high, usually requiring a higher spraying pressure and a larger spray gun nozzle diameter, commonly between 1.5 - 3.0mm.

3. Process Flow

• Water - based Paint: The pre - treatment requirements are relatively high. The surface of the workpiece must be clean, free of oil and impurities, otherwise, it will affect the adhesion of the water - based paint. Generally, multiple water - washing and drying processes are required. Water - based paint can be applied by dipping, spraying, curtain coating, etc. However, due to the significant impact of humidity on its drying speed, in high - humidity environments, additional drying equipment may be needed or the air - drying time may need to be extended.

• Oil - based Paint: The pre - treatment is relatively simple, mainly to remove oil and rust. The application methods also include spraying, brushing, rolling, etc. The drying method is mainly natural drying, and low - temperature drying can also be used, but the drying temperature generally should not be too high to avoid affecting the performance of the paint film.

4. Environmental Protection and Safety

• Water - based Paint: During the operation of the water - based paint spraying line, the VOC content in the exhaust gas is low, causing less pollution to the environment. The wastewater treatment is relatively complex. Special sewage treatment equipment is required to treat the wastewater generated during the spraying process to remove paint residues and harmful substances in the water.

• Oil - based Paint: The oil - based paint spraying line will emit a large amount of exhaust gas containing organic solvents. Effective exhaust gas treatment equipment, such as activated carbon adsorption devices and catalytic combustion devices, needs to be equipped to reduce the emission of organic exhaust gas. During the storage and use of oil - based paint, attention should be paid to fire and explosion prevention because organic solvents are flammable.

5. Maintenance Costs

• Water - based Paint: The water - based paint spraying equipment needs to be cleaned regularly to prevent paint residue from clogging the nozzles and pipes. The cleaning is relatively complex and requires the use of special water - based cleaning agents. The equipment maintenance cost is relatively high because the corrosion of the equipment by water may cause damage to equipment components.Oil - based paint spraying line, Water - based paint spraying line, Automatic painting line

• Oil - based Paint: The cleaning of oil - based paint spraying equipment usually uses organic solvents, which have a good cleaning effect but a high cost, and organic solvents have certain safety risks. The equipment maintenance cost is relatively low because oil - based paint has less corrosion to the equipment.

6. Paint Film Performance

• Water - based Paint: The dried paint film has good water - resistance, corrosion - resistance, and weather - resistance. However, in terms of hardness and wear - resistance, it may be slightly inferior to oil - based paint. It is suitable for occasions with high environmental protection requirements and not extremely strict requirements for paint film performance.

• Oil - based Paint: The formed paint film has high hardness, good wear - resistance, and high gloss, which can better protect the surface of the workpiece. It is suitable for occasions with high requirements for paint film performance, such as the surface coating of automobiles and furniture.