• 펄프종이기술
• /
• 제32권1호
• /
• pp.19-25
• /
• 2000

In Condebelt press drying system, the temperature difference between top and bottom plate of Condebelt transfers water to bottom side, Fine fibers, stickies , ink , and various inorganic materials are also migrated to the fine wire located at the bottom plate by highly pressurized moisture flow. As a result, the fine wire contaminated by plugging of these fine and sticky materials can cause many problems such as blistering or partial crushing of paper. The contaimination of fine wire leads to a deterioroated strength together with uneven physical properties of paper. In this paper, froth-flotatiion method, which is commonly used in the field of ONP recycling process, were adopted to separate the contaminants in KOCC as a new fiber fractionation method. Standard deviation of paper strength and brighteness decreased of Condebelt fine wire were measured to investigate the effect of contaminants removal . The standard deviations of paper strength obtained from the flotated accept were not dependent on the number of condebelt press drying . However, in the case of untreated KOCC, the standard deviations were increased as press drying repeated. This indicates that the contaminant gives uneven physical properties to the paper by wire plugging . Optical and SEM images clearly illustrate the effect of contaminants on the wire condition.

• 펄프종이기술
• /
• 제33권2호
• /
• pp.24-31
• /
• 2001

As a novel method to improve strength properties of recycled test liner, Condebelt press drying system was introduced and adopted into Korea. New press drying treatment could enhance the surface and strength properties in accordance with the increase of sheet density. However, Condebelt drying can not increase the density of repeatedly recycled test liner as much as that of virgin UKP and at the same density condition, the strength of Condebelt press dried UKP is greater than that of press dried test liner. In order to increase the strength of test liner, two attempts were tried in this study. First, addition of polyelectrolytes, dry strength agent was investigated with a view to promote the fiber bonding potential of reclaimed corrugated container pulp. Second, blending effect of fines were analyzed in an aims of increasing density and strength of test liner. The results were as follows; Even in the case of test liner densified by Condebelt press dryer, addition of amphoteric PAM as a dry strength agent was effective in increasing strength properties and so the effect of dry strength agent on improving bonding potential of recycled OCC fiber could be confirmed. As an appropriate addition level of amphoteric PAM, below 1% based on dry pulp weight was suggested. Different from virgin UKP, density of recycled test liner can be increased by the blending of OCC fines and strength properties also can be improved. However, excessive blending of OCC fines could result in decreasing of density and serious weakening of test liner. The best blending ration of fines in test liner can be determined as about 30%. Taking into account the fines content in general OCC pulp as 50%, excessive 20% of fines were supposed to be fractionated and removed in order to achieve the best strength of Condebelt press dried test liner.