Talc is a very important functional component in putty made of unsaturated polyester, e.g. for car and truck bodies. It is used here in proportions of up to 60% by weight. Thus, the quality of the putty ingredient “talc” has a significant effect on putty performance. The rotors of wind power plants, often made from polyester glass fiber composite, need to withstand extreme weather conditions: rain, snow, hail, sub zero temperatures and UV light. Talc used in the polyester gel coat and surface coating of the rotor blade improves the weathering resistance of the rotor.
The softness of pure talc leads to good sandability of polyester putties. It gives high-quality surface finishes after sanding treatment. Pure, flotated Finntalcs, free of abrasive minerals such as chlorite or quartz, have proven to be the best choice.
The pot life is adversely affected by the content of soluble contaminants. Finntalc M40 exhibits the least content of HCl solubles and offers the longest pot life.
Our self-developed talc flotation process for Finntalc leads to a product with very consistent chemical and physical properties. By means of double air classification, oversize particles and fine dust are removed. The lack of very fine particles results in talc products with low oil absorption. This enables the formulator to use less resin, which is both economical and environmentally friendly. This unique combination of properties has made Finntalc M40 and Finntalc M50 the most popular products for polyester putties worldwide.
The highest elasticity is achieved with talcs of low oil absorption. At the same time, their lamellarity increases the adhesion to steel substrate.
Narrowly controlled particle size distributions ensure reproducible paint viscosity characteristics and enable high filler loadings to be achieved. Viscosity and filling level depend on the surface area and structure of the talc particles. Macrocrystalline, coarse, double-classified talcs such as Finntalc M50 permit the highest filling level. Double classified means that the product has passed through two air classifiers, which remove coarse particles in the first step and ultrafines (dust) in the second step. The reduction of fines means that more talc can be added without increasing the viscosity.