Bright Prospects for Durable Paintwork - Wacker Chemie AG


Bright Prospects for Durable Paintwork

Color consistency test (2 mm render, after 1,000 h of QUV testing): The new PRIMIS® AF 1000 binder does a particularly good job of stabilizing pigments for long periods of time (the shorter the bar, the greater the color consistency). While the human eye cannot identify deviations at values below 5, those differences are readily detectable in the lab.

No More Agglomeration

Its composition is what makes this novel product special – at the heart of the dispersion are finely divided mineral and organic particles. The mineral components lend paints and renders considerable mechanical stability, low combustibility and long-lasting, vivid colors. The organic polymer component is based on acrylic esters and produces excellent adhesion to the substrate and a high degree of cohesion and flexibility.

The construction industry has been combining organic and inorganic components in binders for some time, often by simply mixing the mineral particles into an organic dispersion. There is a drawback, however: the particles can agglomerate, which compromises storage stability. Phase separation can also be a problem during film formation, resulting in an uneven, heterogeneous film. This inhomogeneity, in turn, destabilizes the bond and increases the risk of cracking.

“In PRIMIS® AF 1000, WACKER’s new mineralized binder, mineral and organic components are chemically bound together, which prevents them from agglomerating during storage and film formation,” explains Dr. Udo Kotschi, who helped develop the new dispersion at WACKER’s Application Technology department. PRIMIS® AF 1000, he points out, is also characterized by excellent film formation – even at low outdoor temperatures – and by the elasticity of the polymer surface at maximum blocking resistance. The results are stable, homogeneous films.

With the rise of postmodern architecture in the 1980s, vivid colors made a comeback on building sites. A well-maintained appearance requires exterior paints that ensure color consistency.

The Best of Both Worlds

“The launch of PRIMIS® AF 1000 introduces a new binder for sophisticated external applications that combines the advantages of its organic and inorganic components,” says John Fotheringham, who heads the Dispersions & Resins business unit at WACKER POLYMERS. The dispersion, he observes, allows manufacturers to produce coatings in which the color remains consistent – an unattainable goal using the acrylate-based binders available to date. “The recent introduction of the PRIMIS® brand name also signals our intent to expand WACKER’s comprehensive portfolio of high-quality renders and exterior paints,” Fotheringham goes on to note.

The high thermal conductivity of the mineralized dispersion means that paint and facade surfaces dry rapidly. In addition to producing ideal barrier properties, however, PRIMIS® AF 1000 also reduces the amount of dirt that the coating picks up. Thermoplasticity is one of the hallmarks of traditional acrylate dispersions, but it causes the facade to soil more quickly. The new binder technology, on the other hand, provides good elasticity at an optimum level of surface hardness, preventing soiling by making it very difficult for dirt particles to adhere to the surface.

Formulations containing the new WACKER binder are also less combustible thanks to its mineral components. Paints and renders exhibit remarkable dimensional stability under extreme heat, which provides better fire protection and greatly reduces the need for flame-retardant additives in the coatings. PRIMIS® AF 1000 also offers improved scratch and abrasion resistance and optimized thermal conductivity, and makes paints and renders easier to process.