Inhibition of pulp and paper yellowing using nitroxides, hydroxylamines and other coadditives
申请人:——
公开号:US20020124980A1
公开(公告)日:2002-09-12
Pulps or papers, especially chemimechanical or thermomechanical pulps or papers, which still contain lignin, have enhanced resistance to yellowing when they contain an effective stabilizing amount of a hindered amine compound which preferably is a nitroxide, a hydroxylamine or an ammonium salt thereof. This performance is often further enhanced by the presence of one or more coadditives selected from the group consisting of the UV absorbers, the polymeric inhibitors, the nitrones, the fluorescent whitening agents, metal chelating agents, sulfur containing stabilizers, metal salts and diene compounds. Combinations of nitroxides, hydroxylamines or their salts, benzotriazole or benzophenone UV absorbers and a metal chelating agent are particularly effective. Selected derivatives of 1-oxyl-2,2,6,6-tetramethyl-piperidin-4-ol and selected hydroxylamine salts are novel compounds and are surprisingly effective for this purpose.
含有木质素的纸浆或纸张,特别是化学机械或热机械纸浆或纸张,如果它们含有有效的阻化胺化合物(最好是亚硝基自由基,羟胺或其铵盐),则具有增强的抗黄变性能。当与来自紫外线吸收剂、聚合抑制剂、亚硝基醇、荧光增白剂、金属螯合剂、含硫稳定剂、金属盐和二烯化合物等组成的一种或多种协同添加剂一起使用时,通常可以进一步提高其性能。亚硝基自由基、羟胺或其盐、苯并三唑或苯并酚类紫外线吸收剂和金属螯合剂的组合尤其有效。选择的1-氧基-2,2,6,6-四甲基哌啶-4-醇和选择的羟胺盐衍生物是新的化合物,出乎意料地有效。