• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.4
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• pp.14-20
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• 2007

The effects of blending starches with different gelatinization temperatures on the development of ply-bond strength were systematically investigated using a three component mixture design technique. Oxidized corn starches with different gelatinization temperatures were blended with natural corn starch and sprayed for plybonding. Optimum blend ratio for maximizing plybond strength improvement for the starch blends was 40% of natural starch, 27% of oxidized starch with low gelatinization temperature and 33% of oxidized starch with high gelatinization temperature. Starch granules with the lowest gelatinization temperature gelatinizes at the lowest temperature, while the natural corn starch gelatinizes at later stage of drying. The improvement of plybond strength with starch blends were verified on machine trial as well. Plybond strength improvement obtained from the machine trial was lower than that achievable with handsheets, which was attributed to the lower internal bond strength of the linerboards made from recycled fibers.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.3
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• pp.12-23
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• 2007

Frequently spraying of natural starch slurry onto the formed wet web has been adopted to improve properties of paperboards. This conventional starch spraying technique, however, becomes less effective in strength improvement. In this study the effects of various factors including wet web dryness, quantity of starch slurry sprayed, and drying temperature on paperboard properties were investigated. Migration of starch granules into the webs appeared to cause a reduction in plybond strength when the web dryness was lower than this level. Wet webs should contain enough water to swell the starch granules, and at the same time they should be heated to a temperature high enough for complete cooking of the sprayed starches to occur. This suggested that preheating of the wet web can be employed to improve the plybond strength.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.4 s.112
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• pp.38-43
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• 2005

Natural Com Starch(NCS) spray system has been widely used In multiply board mill for the better bonding strength between board layers. However the unsuitable NCS spray system could lead to a drop in plybond efficiency of multiply board. It could also result in the accumulation of unretained-starch in the white water system, which could not only rise in BOD and COD level but also reduce the effects of rosin-alum sizing system and other additives. In this study, the simple and rapid method by UV-spectroscopy for measuring the starch contents in the white water was proposed, and the quantitative analysis for dissolved starch content in white water was carried out in two kinds of board production process. It could be confirmed that about 150 ppm of oxidized starch was retained in white water dewatered from undertop ply of multiply board process, and about 470 ppm of natural starch was dissolved in white water originated from unsuitable spraying system in the multiply board production lines for cup base paper.