When exposed to heat during processing, PVC undergoes dehydrochlorination, releasing HCl and forming conjugated polyene sequences. Methyltin stabilizers, typically mercaptides, counteract this through a dual mechanism: neutralizing corrosive HCl and replacing labile chlorine atoms with stable sulfur-containing linkages.
Rigid PVC (pipe, profile, sheet): Requires high early color hold and long-term stability. Methyl tin at 1.5-2.0 phr is typical for rigid compounds, with additional lubricants (like our G-16 internal and LG-series external lubricants) managing melt flow.
Flexible PVC (film, hose, cable): Lower stabilizer loadings (0.8-1.2 phr) combined with plasticizers demand careful compatibility. Methyl tin’s excellent compatibility with plasticizers prevents bloom and plate-out.
Unistars advantage: We offer the full ecosystem β methyl tin stabilizers (XY-728, XT-188, XY-718), internal lubricants (G-16), and external lubricants (LG78, LG316A, LG70S) β so your formulation is optimized as a system, not piecemeal.