Application of yellowing inhibitors to improve the brightness stability of coated mechanical papers.Application: This study demonstrates the effectiveness of yellowing inhibitors tested for coated BTMP paper. We used laboratory and pilot film coaters to evaluate the effect of yellowing inhibitors on the brightness stability, physical properties, and printability of a coated high-brightness paper made from 100% bleached thermomechanical pulp (BTMP). The yellowing inhibitors consisted of a hydroxyphenylbenzotriazole ultraviolet An invisible band of radiation at the upper end of the visible light spectrum. With wavelengths from 10 to 400 nm, ultraviolet starts at the end of visible light and ends at the beginning of X-rays. The primary source of ultraviolet light is the sun. absorber (UVA) and a hindered hydroxylamine hy·drox·yl·a·mine n. A colorless crystalline compound, NH2OH, explosive when heated, that is used as a reducing agent and in organic synthesis. radical scavenger (RS). After 250 days of ambient Surrounding. For example, ambient temperature and humidity are atmospheric conditions that exist at the moment. See ambient lighting. light exposure, a sheet with a 4 g/[m.sup.2] /side coating lost 27 points ISO (1) See ISO speed. (2) (International Organization for Standardization, Geneva, Switzerland, www.iso.ch) An organization that sets international standards, founded in 1946. The U.S. member body is ANSI. brightness. A sheet with 1.0% RS and 0.11% UVA added to the coating color lost only 11 points brightness. The inhibitors were compatible with the coating formulation and caused no runnability problems. The yellowing inhibitors had a negligible effect on the physical properties and printability of the treated paper. Yuan, Schmidt, and Heitner are with Paprican, Pointe-Claire, Quebec Pointe-Claire is a municipality in southwestern Quebec, Canada; population 29,286 (Statistics Canada, 2001). Along with the other municipalities on the island of Montreal, it was merged with the city of Montreal on January 1, 2002 by the provincial government. , Canada; Fairbank is with Abitibi-Consolidated Inc., Montreal, Quebec. Email Yuan at zyuan@paprican.ca. |
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