Recommendations for the use of water-based baking varnish leveling agent
Water-based baking varnish leveling agent is a key auxiliary agent to improve the appearance quality of the paint film.
Its use needs to be scientifically regulated in combination with process characteristics, substrate type and performance
requirements. The following provides systematic suggestions from four dimensions: dosage control, process matching,
common problem solving and environmental protection and safety:
1. Dosage control
Basic dosage range
Conventional water-based baking varnish: 0.5%-2.0% (for resin solids)
High gloss requirements: 1.5%-3.0% (need to be matched with low viscosity resin)
Low temperature curing system (≤120℃): 1.0%-2.5% (avoid sagging)
Dynamic adjustment strategy
Viscosity synergy: When the viscosity is ≤60 seconds (coating-4 cups), the amount of leveling agent added needs to be
reduced by 0.5%-1.0% to balance fluidity.
Substrate matching: Metal substrates (such as galvanized sheets) need to increase the dosage by 0.5%-1.0% to improve
wettability; plastic substrates (such as ABS) need to be reduced by 0.3%-0.5% to avoid shrinkage.
Color paste effect: The amount of titanium dioxide-containing slurry needs to be increased by 0.5%-1.0% to counteract
surface defects caused by flocculation.
2. Process matching
Spraying process
Atomization pressure: When ≥0.3MPa, the leveling agent needs to be a high molecular weight polyether type to resist
shear force.
Interlayer drying: In the wet-on-wet process, the second coat of paint needs to be reduced by 0.3%-0.5% to avoid interlayer swelling.
Roller coating process
Roller speed matching: When the line speed is >15m/min, a low molecular weight leveling agent needs to be used to avoid splashing.
Film thickness control: When the film thickness is ≥30μm, the addition amount needs to be reduced by 0.5%-1.0% to prevent sagging.
Paint baking parameters
Temperature window: When curing at 120-160℃, select a leveling agent with a temperature resistance of ≥180℃.
Time gradient: Step heating (such as 80℃/30min→140℃/20min) requires a slow-release leveling agent
3. Environmental protection and safety
VOCs control
Select APEO/NPEO-free leveling agent to ensure VOCs≤50g/L (in accordance with GB 30981-2020 standard).
Prefer water-based dispersed leveling agents and avoid solvent-based additives.
Biodegradability
Choose a leveling agent that meets the OECD 301F standard (such as Tego Wet 270) with a biodegradability rate of ≥60%.
Safety protection
Wear a gas mask (in accordance with GB 2890-2022 standard) during operation to avoid inhalation of atomized additives.
Waste is treated as HW12 hazardous waste and handed over to qualified units for disposal.
4. Technology development trend
Nano-leveling agent
Nano-leveling agents with a particle size of ≤50nm can achieve efficient leveling at ultra-low dosage (0.1%-0.3%).
Intelligent responsive leveling agent
pH/temperature responsive leveling agents can automatically adjust surface tension and adapt to complex construction
environments.
Bio-based leveling agent
Bio-based leveling agents (such as soybean oil-based polyethers) made from vegetable oil can reduce carbon emissions
by more than 50%.
Summary
The use of water-based baking varnish leveling agents must follow the principle of "precise matching, dynamic regulation,
and problem-oriented". By scientifically selecting the type of leveling agent, optimizing the addition amount and process
parameters, the comprehensive benefits of 20% increase in gloss, 70% reduction in surface defect rate, and 40% reduction
in VOCs emissions can be achieved. In the future, with the development of nanotechnology, intelligent response materials
and bio-based chemistry, leveling agents will continue to evolve towards high efficiency, functionality, and greenness.
