| 摘要 |
An improved unplasticized polyvinyl chloride composition for forming articles for exterior use such as house siding and window profiles includes a polymeric organic impact modifier, at least one thermal dehydrochlorination stabilizer, and an ultraviolet stabilization system. The ultraviolet stabilization system includes from about 0.2-15 parts by weight of the polyvinyl chloride resin of rutile titanium dioxide and less than about 5 parts by weight of the polyvinyl chloride resin of magnesium oxide. Inclusion of magnesium oxide in the unplasticized polyvinyl chloride composition permits the extrusion of ultraviolet resistant siding and window profiles including relatively low levels of titanium dioxide.
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