Paint thickeners are key additives that adjust paint viscosity and ensure application and film-forming quality. They act like a “viscosity manager” for paint, maintaining its stability during storage, transportation, and application, preventing problems such as sagging, layering, and sedimentation.
Simply put, paint that is too thin will settle and sagging; paint that is too thick will be difficult to brush and affect leveling. Thickeners are used to adjust the paint to the most suitable viscosity for application, ensuring a smooth, uniform, and aesthetically pleasing paint film.
Common Types of Thickeners
Paint thickeners are mainly divided into three categories:
- Inorganic thickeners: such as bentonite and fumed silica, are inexpensive but generally inefficient and can affect transparency.
- Cellulose-based thickeners: such as hydroxyethyl cellulose, are stable and versatile, but their viscosity decreases under high shear conditions.
- Synthetic polymers (emphasis): represented by polyacrylamide (PAM), especially anionic polyacrylamide, which is the mainstream choice for water-based paints.
Advantages of Polyacrylamide:
- High thickening efficiency (small amount is sufficient)
- Does not disrupt the original coating system
- Shear stability, suitable for both brushing and spraying
- Environmentally friendly and non-toxic, aligning with current home decoration environmental trends
Polyacrylamide Applications
Thickeners are used in almost all coating categories, including:
- Architectural Coatings: Latex paint, exterior wall paint, stone-like paint, textured coatings
- Water-based Industrial Coatings: Wood coatings, metal anti-rust paint, water-based wood coatings
- Waterproof Coatings: Roofing waterproofing, kitchen and bathroom waterproofing slurry
- Artistic Coatings: Key additives for creating three-dimensional textures and effects
Suggestions for Polyacrylamide Use and Selection
- For water-based coatings, prioritize polyacrylamide, as it is more compatible and stable.
- Control the amount added; excessive amounts will lead to poor leveling and a sticky paint film, while insufficient amounts will result in inadequate thickening.
- Environmentally friendly: For home decoration and children’s room coatings, choose formaldehyde-free and low-VOC versions for greater safety.
- It is recommended to conduct a small-scale test before application to confirm that the viscosity and leveling properties meet the standards before mass production.