| 摘要 |
Ester contains (i) 5-15% of an acid-binding epoxy cpd.; and (ii) stabilising concn. of a combination of (A) a cyclic phosphonite of formula (a) or (b): (where X is H, OH, NH2, or alkoxy, alkyl(thio), aryloxy or arylthio with 1-22C atoms; Y1 is 1-18C alkyl; Y2 is halogen, 1-18C alkyl or alkoxy, nitro, cyano or sulphonic acid gp.; or Y1 and Y2 are methylene gps. forming a dihydrophenanthrene ring; Z is O or S; m and n = 0-4); (B) a hydroxybenzene triazole of formula (c): (where R is H, halogen, OH, 1-12C alkyl, or aryl; R1 and R2 are H, linear or branched 1-12C alkyl or aryl); (c) a benzoate of formula (d): (where R3 and R6 are H, 1-12C alkoxy or opt. branched 1-12C alkoxy or opt. branched 1-12C alkyl; R4 and R5 are OH one of R4 or R5 may also be H); and (D) an anti-oxidant comprising a sterically hindered phenol. Cellulose esters, and partic. cellulose acetobutyrate, are stabilised against prolonged exposure to sunlight, e.g. for 1000 hrs. or longer. They may contain the usual plasticisers, pigments and dyestuffs. |
