B1B2, 3C2B, 3C1B three kinds of water-based paint process upgrade plan!

Abstract: With the rapid development of China's industrialization, China is also facing serious environmental pollution problems, and the country has successively promulgated a series of laws and regulations.
In response to the large-volume exhaust gas generated during the automobile painting process, source control and treatment of emission reduction are required.
In recent years, OEMs have actively responded to environmental protection policies and carried out upgrading and transformation of coating water-based paint processes.
The article adopted a solvent-based coating production line in accordance with The three water-based paint process plans of B1B2, 3C2B, and 3C1B were compared and analyzed, and the effects of the implementation of the transformation were selected, and the thoughts of upgrading the water-based paint process were explained.

Keywords: water-based topcoat; coating process; upgrading

1.

The automobile coating production line constructed before 2012 in China mainly uses traditional solvent-based topcoats as paint materials, which lag far behind the current mainstream water-based paint processes in terms of environmental protection, safety, and quality.

2.

In terms of environmental protection, laws and regulations require the implementation of raw material substitution projects, process technology transformation projects, recycling and comprehensive treatment projects, and all companies are required to ensure stable and up-to-standard emissions in accordance with standard requirements.

In terms of quality, the solvent-based production line usually adopts natural wind, and the performance and quality of the paint film are restricted.
By adding constant temperature and humidity transformation to the spray booth, the process control ability is improved.

In terms of safety, the original sprinkler fire-fighting system is mainly carbon dioxide fire extinguishing, which has insufficient design and risks, and requires an open-type high-pressure water mist upgrade.

Through the upgrading and transformation of the coating water-based paint process, the production line has been improved in terms of environmental protection, safety and quality to comply with national laws and regulations and improve the market competitiveness of the company's products.

3.

According to the paint materials, the paint line can be divided into traditional solvent-based paint line and water-based paint line.
In recent years, the national environmental protection policy has become more and more stringent.
The "Twelfth Five-Year Plan for Air Pollution in Key Areas" approved and implemented on September 27, 2012 (Huanfa [2012] No.
130) puts forward VOC pollution control as an important part of the environmental impact assessment of construction projects for the coating and coating industry , To adopt strict pollution control measures: new motor vehicle manufacturing coating projects, water-based coatings and other low-VOC content coatings accounted for not less than 80% of the total coating usage.

The traditional solvent-based paint line emission standards can no longer meet the environmental protection standards, and the whole area of ​​the spray paint must be used for the rotary adsorption concentration + RTO exhaust gas treatment process to achieve exhaust gas emission standards.
Due to the large total exhaust air volume, the equipment investment cost is high and the area is occupied.
Large area, high operation and maintenance cost.
The use of water solvents instead of organic solvents in the water-based paint process for intermediate coating, silver base, and color paints is the most effective measure to reduce VOCs emissions from the source.
After the water-based paint process is applied, the waste gas treatment volume is reduced.
The water-based paint process has been widely used at home and abroad.
.
In order to ensure that the exhaust gas emissions from painting meet the environmental protection standards for a long time, this scheme adopts the water-based paint process scheme.

The current water-based paint processes mainly include: B1B2 water-based process, 3C2B water-based process, and 3C1B water-based process.
The three transformation schemes are as follows:

3.

The B1B2 water-based topcoat process requires pre-drying of the color paint.
At present, the length of the original topcoat A line is insufficient.
The spray booth must be extended by about 15.
5m on the original basis (considering the relocation of the central control room), and the line body shall be extended by about 6.
6m.
The construction of line A and B mainly includes: cleaning room, painting room (including air seal), leveling room (adding air curtain), hot flashing (including air seal and cooling), air conditioning, offline polishing room, robot, transportation and adjustment Paint, transportation, electric control, etc.

The A line process layout includes: cleaning, air sealing, BC1 external spray, air sealing, BC2 internal spray, BC2 external spray, paint touch-up, air sealing, hot flashing, air sealing, cooling, air sealing, varnish inner spray, varnish External spraying, paint touch-up, leveling, compared with the original hot flashing process (including air seal, cooling); B line is a water-based solid color paint spraying line, the B line process layout remains unchanged, and at the same time according to the requirements of water-based paint characteristics Public and fire fighting system.

3.

The 3C2B water-based topcoat process requires that the water-based intermediate paint be sprayed and dried before the topcoat is sprayed, that is, the cab can enter the topcoat and spray the water-based paint and varnish after the B-line spraying in the middle of the spraying.

A and B line bodies mainly include: cleaning room, painting room (including air seal), leveling room (adding air curtain), hot flashing (including air seal and cooling), air conditioning, robots, paint transfer, transportation, Electric control, etc.
, while restoring the supporting public and fire-fighting systems.

3.

The top coat A line adopts 3C1B water-based top coat process, and the B line water-based solid color top coat line.
The paint spraying room of line A of the finish paint must be extended by about 30m (the central control room and toilet must be relocated), and the line body shall be extended by about 18.
5m.
The line body mainly includes: cleaning room, painting room (including air seal), leveling room (adding air curtain), hot flashing (including air seal and cooling), air conditioning, offline polishing room, robot, paint transfer, Conveying, electric control, etc.
, and supporting public and fire-fighting systems according to the characteristics of water-based paint.

The process layout includes: cleaning, air sealing, intermediate coating, air sealing, hot flashing, air sealing, silver bottom spraying, silver bottom spraying, paint touch-up, gas sealing, hot flashing, gas sealing, cooling, gas sealing , Varnish inner spray, varnish outer spray, paint touch-up, leveling, adding intermediate coating spraying, intermediate coating hot flashing (including air sealing, cooling), silver bottom hot flashing (including air sealing, cooling) processes compared to the original.

4.

4.
1 Water-based paint process plan

Table 1 Comparison of water-based paint process schemes

4.
2 Reconstruction content of water-based paint (Table 2)

Table 2 Comparison of transformation content of water-based paint

4.

Table 3 Comparison of paint costs of three water-based paint processes

Note: The bicycle cost needs to consider the proportion of metallic paint and solid color paint; the statistics in the table are only the cost of topcoat paint; the paint cost is subject to the manufacturer's quotation, and this table does not reflect the paint price.

4.

The content and cost of the water-based paint process upgrade and transformation mainly involve the cleaning room, spray room, leveling room, hot flashing, air conditioning, offline polishing room, robot, paint delivery and mixing, transportation, electric control, exhaust gas treatment, public facilities, and fire protection system , Safety, Environmental Protection, Occupational Hazards "Three Evaluations", Peripheral Engineering, Workshop Public Facilities, Unpredictable Expenses and Demolition, Civil Engineering, Flooring, High Pressure Water Gun, Exhaust Refining, Drying Furnace Restoration, Cleaning, etc.
Investment in Option One The budget is y ten thousand yuan, the plan two is 0.
87 ten thousand yuan, and the plan three is ten thousand yuan.

4.

Table 4 Comparison of process costs of three water-based paints and existing processes

5.

Because the water-based paint process of Option One and Option Three involves changes in the process layout, the new style spray booth must be renovated on the ground building on the second floor, which affects the load-bearing structure of the house and poses safety risks; at the same time, the transformation cycle is long, which affects the production capacity of the enterprise; in addition, it is combined with stamping, The current status of the process control of assembling and welding appearance plates, and finally choose the 3C2B water-based process plan to implement the transformation.

6 Conclusion

The company has upgraded and transformed the 3C2B water-based paint process.

It can be seen that the water-based paint process plans have their own advantages and disadvantages.