EFFECT OF LITHIUM-BASE CATALYST ON THE RATE OF TRANSESTERIFICATION OF DMT WITH EG AND ON THE QUALITY OF PET

New catalysts combined with an organic or inorganic lithium salt (lithium acetate or lithiumchloride) and a conventional catalyst for the transesterification of dimethyl terephthalate withethylene glycol have been studied. Reaction mechanism in presence of lithium-base catalyst hasbeen proposed. A synergistic action of two classes of catalysts creates the speed-up of initial re-action particularly in presence of lithium acetate. The presence of lithium base catalyst can re-duce diethylene glycol content and raise the melting point of final PET product, but almostuneffect PET molecular weight distribution.     

水分散型感光胶乳的研究

本文提出了一个新型水分散型感光胶乳的研制原理,它包括感光体系和粘合剂体系。此两种体系通过乳化混合成一个稳定的胶乳溶液。光敏体系是由聚乙烯醇的承铬酸盐组成,聚乙烯醇是作为光敏胶体、乳化剂,起保护胶体的作用。粘合剂体系是由环氧树脂和交链剂,醚化酚醛树脂。水分散型感光胶乳适用于印花工业的金属网上,作为光刻胶之用。     

新型复合金属封锁剂

在实验室合成了分子量从980到45000的一系列聚丙烯酸及其钠盐。结果发现分子量较低的聚丙烯酸钠对Fe~(3+)离子具有较高的络合分散力和较强的钙皂分散力。新型复合金属封锁剂是用聚丙烯酸钠和其它助剂复配而成。同日本商品金属封锁剂K相比较,复合金属封锁剂对钙皂分散力和络合Ca~(2+)离子的能力较封锁剂K好。用复合金属封锁剂精烁后的丝绸白度为87,而封锁剂K精炼后的丝绸的白度为86.2。根据本文所得结果表明新型复合金属封锁剂是一种有效的丝绸精炼助剂。