| 摘要 |
PIPERIDYL- AND BENZOATE-BASED STABILIZER SYSTEM FOR POLYOLEFIN PIGMENTED FIBERS AND THIN FILMS Excellent color stabilization as well as integrity is obtained in thin film and fibers exposed to bright sunlight at relatively high temperature, in polyolefin (PO) articles pigmented with blue and green phthalocyanine, and red azo and disazo pigments. The pigment is combined with two 'large molecule' primary stabilizers, the first a piperidyl-based (PDYL) hindered amine light stabilizer (HALS), and the second, a 3,5-disubstituted-tert-butyl-4-hydroxybenzoate (3,5-DHBZ). The first contains at least two polysubstituted piperidyl rings in its molecule; the second is a hindered phenol with an ester group in the para- position. Stabilization of the PO's color is obtained for as long as the PO articles themselves are stabilized by the combination of primary stabilizers, typically, their useful life. With the combination, the pigmented articles are not only thermooxidatively and light-stabilized, but there is exceptionally low color fade. Because fibers may be extruded twice for better distribution of pigment, a small amount, no more than 0.1 phr of secondary melt-stabilizers, may be used. Bluegreen- and red pigmented PO articles exhibit less than a ?3 change in color (color fading) due to degradation of the pigment, over a period of exposure resulting in absorption of 1240 Kjoules/m2. Such exposure of pigmented articles, deemed equivalent to normal outdoor use over a period of more than 10 years, results in essentially no visible loss of color due to degradation of the pigment.
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