(403e) Evaluation of DRY Strength Additives FROM NATURAL Resources of Indian ORIGIN
EVALUATION OF DRY STRENGTH ADDITIVES FROM NATURAL RESOURCES OF INDIAN ORIGIN
A.K. Ray ,and Ghosh U K
Department of Paper Technology, Indian Institute of Technology Roorkee, Saharanpur Campus, Saharanpur
There are many additives used during paper making, such as, in the beating or refining process and as strength additives. It is well known that additions of dry strength resin increase the mechanical strength properties of paper such as tensile and burst indices by increasing the interfiber bonding without affecting the tear strength.It is used to reduce the fuzz or lint on the paper surface, and to increase the internal ply-bond strength. The most common dry strength additives are starch and its substitutes like oxidized starch, cationic starch and poly-acryl-amide polymer. These are normally synthetic and some are semi synthetic in nature. Though additions of polyacrylamides can give superior properties but it is very expensive compared to starch based chemicals. In India gums like guar gum, locust bin gum and seed gum of sebania aculeate etc. are available in plenty which can be a good substitute of either cationic starch or polyacrylamides. Earlier trials has been tried, but the data are not available in literature. An attempt has been made in the present investigation to explore the potential of guar gum as dry strength additives in paper industries. Experiments were conducted with Guar Gum at various percentage (0.5 to 5.0%) on OD fibers.
The freeness value( actually slowness), 0SR of the pulp were also varied between 35 to 450SR, and the results were evaluated. To compare its effects parallel runs were also tried with oxidized starch, maintaining the same doses of additive, 0SR value , mixing time and degree of agitation. For a given strength guar gum additive requires less magnitude of refining. It is expected that by decreasing refining ,tearing strength, drainage aid requirements and permeability will decrease and consequently demand of refining energy will also decrease.
From the experimental data it is found that guar gum can be a promising dry strength additives which can give requisite dry strength in paper. A blank test without addition of dry strength additives has also been tried for comparison purposes. However all these cases that is blended with guar gum and with oxidized starch the internal sizing agent has been kept constant i.e. rosin and alum with a fixed ratio(1:4).