Dover Chemical: New calcium stearate increases PVC heat stability
A new lineof calcium stearates for PVC processing reportedly provides better early color and much longer heat stability than traditional calcium stearates. In consequence, tin stabilizer levels can be cut by 25 to 50%, says Dover Chemical Corp., Dover, Ohio. Its new Doverlube TriCal products are novel over-based stearates that contain three times the amount of calcium as traditional calcium stearates. Brabender studies have shown TriCal to increase long-term heat stability by 21 to 36%, depending on the tin stabilizer used. The TriCal 30 Series is best suited to applications with reverse-ester methyltin stabilizers. TriCal 40 Series is recommended for thioglycolate methyltin systems. Market manager Bill Hood says PVC processors can work compounds harder without deterioration of color or performance.