Wood-containing papers

HEITNER Light-Induced Yellowing of Wood-Containing Papers... 

C Heitner. Light-Induced Yellowing of Wood-Containing Papers An Evolution of the Mechanism. In C Heitner and JC Scaiano, eds. Photochemistry of Lignocellulosic Materials. ACS Symposium Series, 531. Washington, DC American Chemical Society,... 

C Heitner. Light-induced yellowing of wood-containing papers An evolution of the mechanism. ACS Symp Series 531 (Photochemistry of Lignocellulosic Materials), C Heitner, JC Scaiano, Eds. Washington, DC, Amer Chem Soc., 1993, pp. 2-25. 

Next, we will focus on a laboratory study of mannan sorption onto both mechanical and chemical pulps that are relevant in the production of wood-containing papers, as chemical pulps are often also added as reinforcement fibers. The sorption experiments were performed with GGMs isolated from spruce, or enzymatically modified guar gum GMs. The amount of sorbed mannan was calculated by measuring the amount of mannan left in solution by acidic methanolysis followed by GC analysis. 

Paper grades that contain pulp produced by mechanical or chemimechanical processes are referred to as wood-containing papers. Mechanical pulps are mainly used in short-Hfe printing papers, hygienic papers and board. 

This is a specialty filler, applied to the sheet mainly in order to increase light scattering/opacity and to reduce the ink print-through potential. Typical areas for the application of calcined clay are lower basis weight uncoated wood-containing papers (i. e. telephone directories, low basis weight newsprint and SC paper etc.). 

Wood-containing papers are mainly single-coated (LWC). Coat weights are usually between 5 and 10 g m per side. Traditionally, the coat is applied with a blade coater. More modern installations use a film press for the single coat. 

Waste paper has become one of the most important raw materials for the production of paper and cardboard [1]. Besides simple repulping, deinking has become the best known technique for waste paper recycling. Deinked stock is the predominant raw material in the manufacture of newsprint, recycled graphic paper and sanitary paper in Central Europe, and its use in wood-containing paper for magazines is likely to become possible within the near future [2]. 

Heitner, C. Light-induced yellowing of wood-containing papers—an evolution of the mechanism. In Heitner, C., Scaiano, J.C. (eds.) Photochemistry of Lignocellulosic Materials. ACS Symposium Series No. 531, p. 2. American Chemical Society, Washington DC (1993)... 

In a recent study, the authors studied a model system relevant to lipophilic wood pitch in mechanical pulp and further manufacturing of wood-containing paper [24]. Wood pitch, which is colloidally dispersed as a dilute emulsion of pitch droplets, was analysed for the distribution of resin and fatty acids between the lipophilic phase, mainly composed of triglycerides and steryl esters, and the water phase in the pH range 3-11. The study aimed at obtaining better understanding of the behaviour of pitch in pulp and paper mills. These phenomena are important with regard to pitch removal, but have implications also on the formation of sticky pitch deposits on paper machines, and even on the properties of the produced paper. 

Paper made of pure cellulose is designated as wood-free paper, whereas that made from mechanical wood is called wood-containing paper. 

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