A common problem in paint production and storage – Haze!
Introduction: For small and medium-sized coating factories, the “Haze” phenomenon in clear coats and clear oils is a quality alert that cannot be ignored. It not only affects the product appearance but also acts as a potential threat to film-forming performance and stability. This article will conduct an in-depth analysis of the root causes of this issue and provide a complete set of solutions, ranging from emergency treatment to root cause prevention and control.
What Is Haze in Paints?
Coating Haze, also known as turbidity, haziness, or muddiness, refers to the cloudy and opaque appearance of clear coats, clear oils, or thinners caused by the precipitation of insoluble substances. For example, after opening the can, clear coats, oil-based clear coats, and synthetic resin clear coats may show poor transparency, turbidity, or even precipitation.
Main Causes of Haze
- Improper solvent selection or excessive use leads to partial precipitation when solubility parameters mismatch.
- Moisture in the coating’s solvent or film-forming material can cause drier precipitation and turbidity.
- Excessive storage time or improper temperature.
- Inappropriate selection of driers, especially lead-based ones, can cause clear coats to turn turbid even with slight moisture or at low temperatures.
- Poor paint quality, or mixing two types of clear coats with different properties.
Solutions to Coating Haze
- Add turpentine or aromatic solvents to improve thinners; choose based on film-forming materials. For example, add a little turpentine to slow-drying clear coats with too much solvent, and small butanol or benzene-based solvents to fast-drying ones (e.g., nitrocellulose).
- Remove moisture from thinners during coating production. Separate acetone, ethanol, alcohols via fractional distillation; benzene, gasoline, turpentine via stratification. Seal solvent barrels tightly, avoid construction on rainy/high-humidity days. Fix turbid clear coats by heating or laying barrels flat to settle moisture.
- Improve coating storage: avoid extreme temperatures, use within shelf life. Keep clear coat storage above 20℃, place barrels on wooden racks. Slightly turbid ones work normally; for severe cases, heat to 60-65℃ in water bath (no open flame, don’t fully seal barrels, prevent moisture mix-in).
- Choose proper driers for alkyd clear coats (cobalt, manganese, iron blends). Avoid lead driers; reduce amount with more oil unsaturation. Add 0.04%-0.06% cobalt and 0.3%-0.5% lead to alkyd resin driers.
- Try not to mix different types of clear coats.
- Severely turbid clear coats (unfixable): use for putty, downgrade or discard.
What We Offer
If you are a paint or ink manufacturer facing haze or stability issues, we offer:
- Custom formulation design – improve compatibility and performance.
- Raw material supply – complete resin, additive, and solvent solutions.
- Process guidance – technical support from lab scale to production.