| 摘要 |
1,188,342. Coated paper. WEST VIRGINIA PULP & PAPER CO. 13 March, 1967 [16 March, 1966; 17 June, 1966], No. 11756/67. Heading B2E. [Also in Divisions B5 and D2] A particulate material for paper manufacture comprises blushed fine fibres of a cellulose ester. These fibres are white and opaque 0.03 m.m to 1.86 m.m long, 2 to 51 microns wide, interlock to form self-supporting waterleaves, and have a Williams freeness for 1 gram of 23 to 573 seconds at a consistency of 0.1%. They may contain a mineral pigment, particularly clay, calcium carbonate, aluminium silicate, hydrated alumina or titanium dioxide or mixtures. They may be made by spraying a solution of a cellulose ester into a first non-solvent miscible with the solvent of the solution, the solution also including a second non-solvent miscible with both the solvent and the first non-solvent. Solvents referred to are acetone, methoxy-ethyl acetate and ethyl lactate; first non-solvents are water and water-acetone mixtures; and second non-solvents are water, methanol and ethanol. The solution may also contain a wetting agent, e.g. a fatty-acid soap, trisodium phosphate, sodium phosphate, nonyl-phenoxypoly (ethyleneoxy)-ethanol, a polyalkylene glycol or a polyoxyethylenatedalkyl amino-amide, or a plasticizer, e.g. di-n-butyl sebacate. Waterleaf sheets of high opacity may be made from the blushed fibres alone or mixed with conventional wood pulp, with or without a clay filler, and may be coated with an aqueous composition comprising titanium dioxide, clay, starch and latex. The spray solutions used in the Examples comprise (1) acetone, water, sodium stearate and scrap cellulose acetate butyrate containing 20% of plasticizer; (17) cellulose acetate, di-n-butyl sebacate and acetone; (18) acetone, water, cellulose acetate butyrate and sodium stearate; (19) cellulose acetate butyrate, acetone and water; (20) acetone, water, soap, cellulose acetate and plasticizer (di-n-butyl sebacate) in various proportions; (21) acetone, water, sodium stearate, cellulose acetate butyrate scrap, and cellulose acetate containing 6% TiO 2 ; (22) acetone, water, sodium stearate, titanium dioxide and scrap cellulose acetate butyrate; (26-30) acetone, water, sodium stearate, cellulose acetate butyrate and mineral filler, which was titanium dioxide alone (Example 26), or mixed with aluminium silicate (Example 27), clay (Example 28), calcium carbonate (Example 29), or calcined clay (Example 30); (31) acetone, water, sodium stearate, TiO 2 and cellulose acetate. |
