Effect of Pentaerythritol Derivatives as Additives for Poly(vinyl chloride)

Abstract

Pentaerythritol derivatives such as mono-, di-, tri- and tetraesters of 2-ethylhexanoic acid, and mono- and dibenzylidene ethers were prepared as additives for PVC. These materials were mixed with DOP (20 phr) and Zn stearate/Ca stearate (2/1) (3 phr) at 150°C for 10 min using an open roll. Compounded PVC films were heated at 160°C up to 120 min in a circulating air oven to examine the synergetic effects of these materials on inhibiting zinc burning, so-called stabilization of PVC.
1) Monobenzylidene ether, mono- and diesters in the coexistence of metal soaps slowed down the appearance of zinc burning and prolonged good initial color of PVC films. The synergetic effects would be attributable to the formation of the colorless complex between two hydrxyl groups in the molecules and zinc chloride formed.
2) Mono-O-(2-ethylhexanoyl)pentaerythritol showed the greatest synergetic effects among these materials, and had a good solubility in PVC-DOP. Therefore, it can be used practically as a secondary stabilizer instead of pentaerythritol with Zn/Ca soaps.