Manufacturing of Magnetic Papermaking Fibers and Paper (Part I)

Abstract

(1) Magnetic papers were made from magnetite and ferrite lumen-loaded pulps. When the papers were made only from the magnetic pulps, its breaking strength and burst factor were 5.1km and 313kPa/g/m2, respectively. The breaking strength and burst factor of the papers increased to 6.5km and 461kPa/g/m2, respectively, by addition of 2-3% fibrous Polyvinyl Alcohol (PVA) binder. Thus, physical properties of the magnetic papers added with PVA were nearly equal or rather superior to those of papers from unbleached softwood kraft pulp (USKP). Saturation magnetization value of each paper prepared from manganese-ferrite and manganese-zinc-ferrite lumen-loaded pulps was 16.1, 15.7 and 21.2emu/g, respectively, and each remanent magnetization value was 3.5, 3.1 and 4.5emu/g, respectively.(2) In the next experiment, magnetic papers were made by mixing a magnetic pulps and USKP by changing the mixture ratios of 0, 40, 70 and 100%. Breaking strength of these papers decreased with the increase in the added amount of USKP to the pulps. When the 2% PVA binder was added to the magnetic pulps (without addition of USKP), breaking strength of the papers was almost same as that of USKP. Magnetic properties of the papers prepared by mixture of manganese-zinc-ferrite lumenloaded pulps and USKP decreased in both their saturation magnetization values and their remanent magnetization values with the decrease in the mixture ratio of the magnetic pulps.(3) Furthermore, combination papers were made from a magnetic papers prepared from pulps lumen- loaded with magnetite and ferrite and a bleached softwood kraft papers (BSKP). When the 1-2% PVA binder was added to the papers, the interlayer stripping strength of the combination papers having two or three layers was improved to 1.7N at the 50mm sample width, thus the composite papers having sufficient inter-layer strength were obtained.(4) Security papers endowed higher security were made by sparsely binding of magnetite, manganese-ferrite or manganese-zinc-ferrite lumen-loaded pulps and BSKP.