| 摘要 |
<p>1396891 Paper FELDMUHLE ANLAGEN UND PRODUKTIONS GmbH 18 March 1972 [18 March 1971] 48615/71 Heading D2B [Also in Division B2] Paper suitable for use as electrophotographic copying material and having a weight of up to 70 grams per square metre comprises a cellulosic inner layer and, on each side, an outer layer comprising a polymer containing hydroxyl and/or amino groups which has been cross-linked by reaction with a melamine- and/or urea-formaldehyde precondensate, the outer layer on each side having a weight of up to 3 grams per square metre. The polymer containing hydroxyl groups may be a polyvinyl alcohol, starch, or a derivative thereof e.g. an ethoxylated starch. The polymer containing amino groups may be gelatine. The outer layers may, in addition, contain a thickener e.g. bentonite, and a proteinaceous material e.g. casein or soya bean protein. Crosslinking may be effected together with cyanamide, and with the aid of catalysts. The paper may be made by coating an optionally sized paper web on the paper-making machine with the polymer and precondensate either separately or in admixture using size presses or other coating apparatus. The cellulosic paper may be one which has been made in an alkaline medium, and may contain a filler e.g. calcium carbonate or china clay. Sizing may be effected using a ketene dimer and a cationic polyamide resin.</p> |
