Reference

Reductive bleaching of mechanical pulp

Reductive bleaching of mechanical pulp. Melzer, Jaroslav (BASF A.-G. , Fed. Rep. Ger.). Ger. Offen. DE 3308298 A1 13 Sep 1984, 8 pp. (German). (Germany). CODEN: GWXXBX. CLASS: IC: D21C009-10. APPLICATION: DE 83-3308298 9 Mar 1983. DOCUMENT TYPE: Patent CA Section: 43 (Cellulose, Lignin, Paper, and Other Wood Products) Blending of mech. pulp with dithionite or formamidinesulfinic acid [1758-73-2] in the presence of complexing agents at 40-100° gave products with high whiteness. Thus, 1000 mL pulp suspension of 4% consistency was treated with 0.2% diethylenetriaminepentamethylenephosphonic acid (I) [15827-60-8] on the basis of dry pulp, stirred for 30 min at 60°, treated with 1% Na2S2O4 and stirred for 60 min at 60° to give product with 68.1 whiteness, as compared with 62.5 whiteness for pulp bleached in the absence of I.

Peroxy acid bleach compositions and method

Peroxy acid bleach compositions and method. Richardson, David Leroy (Procter and Gamble Co., USA). Eur. Pat. Appl. EP 103416 A1 21 Mar 1984, 28 pp. DESIGNATED STATES: R: BE, DE, FR, GB, IT, NL. (English). (European Patent Organization). CODEN: EPXXDW. CLASS: IC: C11D003-39. APPLICATION: EP 83-304700 15 Aug 1983. PRIORITY: US 82-409735 19 Aug 1982. DOCUMENT TYPE: Patent CA Section: 46 (Surface Active Agents and Detergents) Granular bleach compns. are prepd. which contained a surface-active peroxy acid (I), such as perlauric acid, and org. chelating agent, such as Dequest 2041 [1429-50-1], Dequest 2000 [6419-19-8], Dequest 2060 [15827-60-8], or Versenex 80 [140-01-2], and, in some cases, Na5P3O10. The chelating agents and the Na5P3O10 retard the decompn.and/or inactivation of I by Mg2+ or Mg2+ and Ca2+ ions in the bleaching bath. The chelating agents also are effective for decolorizing hydrophilic stains on which the surface-active peroxy acid bleaches are less effective. Thus, a bleaching soln. was prepd. which contained Mg2+ 111, Na alkylbenzenesulfonate 250, Na5P3O10 488, and Dequest 2041 3ppm as well as sufficient perlauric acid (as urea adduct) to give 5 ppm available O. The soln. contained 4.5 ppm available O after 5.0 min, compared with 4.2 when the soln. contained no Dequest 2041 and 4.6 when the soln. contained no Dequest 2041 and no Mg2+.