Mark TK 262 GV Butyltin mercaptide/carboxylate Crompton-Witco Heat stabilizer for PVC plastisols >> Organotin Polyvinyl Chloride (PVC) SEALANT >> Plastisol MARK Ò TK 262 GV Butyltin mercaptide/carboxylate stabiliser acting as foaming catalyst Clear, yellowish, low viscosity liquid Depending on the type of PVC used MARK TK 262 GV gives excellent heat stability in virtually all PVC processing methods. The product is used not only as stabiliser at high processing temperatures but also as foaming catalyst (kicker) in rigid and plasticised PVC. In the melt, organotin stabilised PVC has the tendency to stick to hot metal parts. The choice and concentration of external lubricants is particularly important. Like all organotin mercaptide stabilisers MARK TK 262 GV has a very good compatibility with PVC; plate -out and exudation problems due to the stabiliser are therefore practically unknown. MARK TK 262 GV gives highly transparent finished articles provided a suitable type of PVC and lubricating system are chosen. A comparison of the property profiles of the different MARK butyltin stabilisers is given in our Product Survey (Additives for PVC Processing). In rigid PVC processing the addition of external lubricants such such as montan waxes or complex esters (0.2 - 0.5 phr) as well as PE waxes or oxidised PE waxes (0.05 - 0.1 phr) has proved to give good results; however, it is not recommended to add stearic acid. According to the processing methods internal lubricants at concentrations of 0.5 - 2.0 phr are added to rigid PVC formulations; it is recommended to use fatty acid glycerides such as MARKLUBE Ò as they are highly compatible with PVC. In some rigid PVC processing methods an increased melt elasticity is particularly important and the use of PMMA processing aids has proved to give good results. In addition they improve the homogeneity and surface quality of the finished article. In the production of rigid PVC foam the addition of 6 - 10 phr of a higher molecular type, e.g. Vestiform Ò R 340 has proved to give good results. As an external lubricant, MARKLUBE 371 has proved particularly effective; the addition of internal lubricants is not required. In some rigid PVC processing methods an increased melt elasticity is particularly important and the use of PMMA processing aids has proved to give very good results. In addition they improve the homogeneity and surface quality of the finished article. Plastisols In the production of CV flooring MARK TK 262 GV gives excellent transparency and brilliance. If MARK TK 262 GV is used as a foaming catalyst in most cases combinations with a zinc component (zinc oxide or zinc octoate) are recommended. Optimum concentrations depend on the formulation and should be determined in preliminary tests. Dosage Rigid PVC: 1.5 - 3.0 phr. Plasticised PVC: 0.4 - 1.0 phr. Plastisols: 0.5 - 1.5 phr. Low viscosity, high processing temperatures, butyltin mercaptide/carboxylate stabiliser for PVC. Used as foaming catalyst in rigid and plasticised PVC. Gives very good heat stability, transparency and brilliance. Possesses very good compatibility with PVC. Use level : rigid PVC: 1.5-3.0 phr plasticised PVC: 0.4-1.0 phr plastisols: 0.5-1.5 phr