This study was carried out on sheets from spruce CTMP fibers, which are surface treated with a mix of cationic starch and CMC and blended with 20% bleach softwood chemical pulp fibers before handsheets were prepared in a Rapid Köthen sheet former, where the sheets were dried to 40-55% d.c. The sheets were pressed in a hot press nip in a pilot machine with adjustable pressure and heat. Both low and high nip pressure were used in combination with two different nip temperatures, 80°C and 100°C, to achieve sheets in a broad range of densities. The results show that remarkable improvements are possible, both in terms of tensile index (up to 85 kNm/kg) and compression strength, SCT, (up to 38 kNm/kg) on the CTMP-based sheets under optimal conditions at papermaking, i.e. consolidate the sheet structure in a press nip at evaluated temperatures.
It is evident from the current study that there is an as of yet unexploited potential in modifying the conditions of papermaking from spruce CTMP furnishes, which can be utilized for the manufacturing of papers with high requirements on strength and stiffness, e.g. packaging papers.
Adsorption, CMC, CTMP, Heat, Polyelectrolytes, Pressure, Starch, Tensile index
Nordic Pulp & Paper Research Journal (NPPRJ) is an international scientific magazine covering science and technology for the areas of wood or bio-mass constituents, pulp and paper and including new fiber-based materials, recovery and by-products from pulping processes, bio-refining and energy issues. Articles meeting required scientific standards are accepted from any continent. Open Access: Articles not available through Gold Open Access may be purchased by credit card as a pdf file, to be downloaded within 24 h after ordering, at a price of 22 EUR per article. (Value added tax may apply depending on your location, which you enter at payment logout.) Such articles have Green Open Access, i.e. authors may share articles on their personal non-commerical homepage immediately after publication on the website and download them to non-commercial hosting platforms one year after publication in a full issue of NPPRJ. ISSN: 0283-2631