Keep your walls clean and fresh for long!
Exterior wall-coatings deteriorate with time, and there can be various reasons for this.
- In Asia-Pacific countries, environmental factors such as dirt, moisture, light and temperature variations can be particularly harsh on the coating’s surface.
- As groundwater present in various masonry substrates evaporates with time, salt dissolved in it is brought to the surface of concrete, brick, stucco, or natural stone surfaces, leaving behind white crystalline deposits, a phenomenon called efflorescence.
- The material used in these substrates move gradually causing cracks and additional stress on the coating. These cracks absorb moisture and ruin the wall plaster surface. To overcome this, paint chemists usually lower the hardness of the paints, which compromises its resistance to dirt. This means that the paint allows and retains dirt from the environment.
Adding dirt resistance to paint
At the core of any water-based paint is the polymer dispersion which imparts most of its functional properties. Weather conditions have a huge impact on the durability of the exterior coating, affecting its qualities such as
- Color retention: Ability of the paint to not fade and remain fresh-looking for years
- Alkaline and efflorescence-resistance: Ability of the paint to absorb the salt deposits and not show efflorescence, explained above
- Crack-bridging ability: This refers to flexibility in the paint layers which allows it to bridge a crack quickly and seamlessly
- Dirt-pickup resistance: The ability of the paint to remain clean without accumulation of surface dirt
It then becomes a challenge for paint manufacturers to formulate a dirt pick-up-resistant (DPUR) paint that is elastic enough to bridge surface cracks. It should also form a barrier with low water uptake (i.e. high water resistance) and high water-vapor permeability. As a result, liquid water cannot permeate through the surface, but water vapor can be harmlessly passed through the coating to prevent water build up and potential adhesion-loss problems.
Advances in polymer chemistry provide the answers to this puzzle. It helps paint manufacturers formulate a paint that shows all of these properties:
- Good dirt resistance
- Water resistance
- Elastic behavior leading to higher tensile strength and elongation
- UV-cross-linking efficiency: This helps the paint cure quickly in the initial stages
- High permeability of water vapor without sacrificing water uptake
This way, the durability of the paint coating is enhanced, while also retaining its fresh appearance for long.
Clean, fresh walls: The BASF solution
BASF offers an excellent remedy to the age-old problem of dusty, grubby walls with its Acronal® 7079 polymer dispersion product that acts as a binder in the paint, allowing the coating (or paint) to resist dirt, dust, peeling, cracking, chalking and efflorescence build-up over time.
Owing to its unique cross-linking structure, this innovative product from BASF helps prevent formation of surface cracks and creates a good water-barrier and water-vapor permeability. Acronal® 7079 can be included in the paint to provide dust resistance and crack bridging.
So the next time you despair over the state of your walls, simply ask your paints supplier for paint that has the best dirt-resistance and water-proofing properties. This will not only help enhance exterior aesthetics but also overcome the impact of hairline cracks.