Preparations and properties of new monomeric light stabilizers

Abstract

Six new monomeric light stabilizers have been synthesized by a two-step controlled isocyanation. In the first step methacrylic acid (MAA) or acrylic acid (AA) reacts with toluene-2,4-diisocyanate (TDI) or hexamethylene diisocyanate (HMDI) at a mole ratio of 1 to 1 to form an intermediate. In the second step this intermediate was directly added to 2,2,6,6-tetramethyl-4-piperidinol (TMP) or 2,4-dihydroxy benzophenone (DHBP) at a 1 to 1 mole ratio at a given temperature in the presence of dibutyltin dilaurate (DBTDL) catalyst. These six new monomeric stabilizers are 2,2,6,6-tetramethyl-4-piperidinyl, (4-methacryloyl amino) tolyl carbamate-2 (A); 2,2,6,6-tetramethyl-4-piperidinyl, (4-acryloyl amino) tolyl carbamate-2 (B); 2,2,6,6tetramethyl-4-piperidinyl, (6-methacryloyl amino) hexyl carbamate-1 (C); 2-hydroxy-4-benzophenonyl, (6-methacryloyl amino) hexyl carbamate-1 (D); 2,2,6,6-tetramethyl-4-piperidinyl, (6-acryloyl amino) hexyl carbamate-1 (E) and 2-hydroxy-4-benzophenonyl, (6-acryloyl amino) hexyl carbamate-1 (F). These new monomeric light stabilizers were characterized by IR, NMR, UV and elemental analysis. Their stabilizing action for protecting polypropylene (PP) against photo-oxidation and polymerizability were examined. © 1998 Elsevier Science Ltd. All rights reserved.