I. An Irreversible Industry Transformation
As the state's control over VOC emissions becomes increasingly stringent, the "14th Five-Year Plan" explicitly proposes promoting the application of low-VOC-content coating products. Waterborne coatings are shifting from an "optional alternative" to a "mainstream choice." However, for industrial users, what are the substantive differences between waterborne and solvent-borne coatings? When is it feasible to switch to waterborne, and when is solvent-borne still indispensable?
This article conducts a comprehensive comparison from four dimensions: environmental performance, physical properties, construction process, and cost analysis, to help procurement and technical personnel make rational decisions.
II. Core Differences: The film-forming mechanisms are completely different.
Oil-based paint (solvent-borne coating)
Using organic solvents (toluene, xylene, esters, ketones, etc.) as thinners, the resin is dissolved in the solvent to form a homogeneous liquid. After application, the solvent evaporates, and the resin molecules crosslink and cure to form a paint film. The solvent is 100% volatilized into the atmosphere during the curing process.
Water-based paint (waterborne coating)
Using water as the diluent, the resin is dispersed in water in the form of tiny particles (emulsion). After application, the water evaporates, and the emulsion particles fuse into a continuous paint film. Among the volatiles, over 90% is water vapor, with only a small amount of film-forming aid.
III. Comprehensive Comparison Across Four Major Dimensions
1. Environmental performance
| Indicator | Water-based Paint | Oil-based Paint |
|---|---|---|
| VOC Content | <50g/L | 400-600g/L |
| Harmful Gas Emissions | Extremely Low | Contains benzene series, formaldehyde, etc. |
| Worker Health | Safe, no special protection needed | Requires respirators, ventilation equipment |
| Waste Disposal | Ordinary industrial wastewater | Hazardous waste, high disposal cost |
| Fire Rating | Non-combustible, no explosion-proof needed | Flammable and explosive, requires explosion-proof warehouse |
2. Physical Properties
| Performance Metric | Water-based Paint | Oil-based Paint |
|---|---|---|
| Hardness | H-2H | 2H-3H |
| Adhesion | Excellent (on polar substrates) | Excellent (on various substrates) |
| Water Resistance | Good-Excellent (mature technology) | Excellent |
| Chemical Resistance | Moderate-Good | Excellent |
| Outdoor Weathering | Good (acrylic/silicon-acrylic systems) | Excellent (polyurethane/fluorocarbon systems) |
| Fullness/Gloss | Moderate (continuously improving) | Excellent |
3. Application Process
Key points for water-based paint application:
- Optimal application temperature: 15–35°C, humidity 40–70%
- Drying speed is greatly affected by ambient humidity; high-humidity environments require extended drying time.
- Higher requirements for substrate surface preparation (oil stains and dust must be completely removed)
- Tools and equipment can be cleaned with clean water.
- Can be applied wet-on-wet, improving efficiency.
Key points for applying oil-based paint:
- Wider application temperature range: 5–40°C
- Fast drying speed, minimally affected by ambient humidity.
- Good leveling, resulting in a smoother film appearance.
- Tools must be cleaned using organic solvents.
- The construction interval must be strictly controlled.
4. Cost Analysis
| Cost Item | Water-based Paint | Oil-based Paint |
|---|---|---|
| Coating Unit Price | Slightly higher (10-30%) | Baseline |
| Coverage Rate | 6-10 m²/kg | 6-10 m²/kg |
| Application Efficiency | Wet-on-wet applicable, higher efficiency | Requires waiting for drying |
| Environmental Compliance Cost | Low (compliant emission) | High (exhaust treatment + RTO equipment) |
| Total Cost | Lower in the long run | Low raw material cost but high hidden cost |
IV. When should you choose water-based paint? When is it still necessary to use solvent-based paint?
Scenarios where water-based paint is preferred:
- Architectural coatings (interior/exterior walls, flooring) — waterborne rate has exceeded 90%, with the most mature technology.
- Wood coating (furniture, flooring) — water-based UV coatings now match the performance of solvent-based PU coatings.
- Automotive OEM painting – waterborne intermediate coat and basecoat have become widespread, with VOC emissions reduced by over 80%.
- New plants with environmental compliance requirements—avoid later VOC treatment retrofit costs
- Export products to Europe and America—compliant with international environmental standards such as REACH and CARB
Scenarios where oil-based paint is still required:
- Heavy-duty anti-corrosion fields (C4–C5 environments, offshore engineering) — the salt spray resistance of waterborne coatings is still insufficient to meet extreme service conditions.
- Inner walls of chemical equipment — requiring resistance to strong acids, strong alkalis, and organic solvents
- Low-temperature / high-humidity application environment — water-based paint is difficult to dry
- Ultra-high decorative requirements (automotive topcoats, high-end 3C products) — solvent-based paints still have advantages in gloss and fullness.
V. Kexin's Waterborne Product Portfolio Layout
Kexin New Materials has established a complete waterborne coating product line, covering mainstream application fields such as waterborne industrial coatings, waterborne wood coatings, and waterborne architectural coatings. Our waterborne products have passed SGS environmental testing, with VOC content below 50 g/L, meeting the latest national standard GB 30981-2020 requirements, and we provide construction technical training and on-site guidance services.
Whether you are planning a production line upgrade or building a new factory, the Kexin technical team can provide a professional waterborne conversion solution.