• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.5
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• pp.39-44
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• 2007

In order to utilize unsorted ONP, which contains leaflets (printed coated papers), as a raw material to produce pulp mold, optimum conditions for repulping were investigated with the pilot Helico pulper at Centre Technique du Paper (CTP), France. Two major process factors were focused: repulping concentration and rotor speed. Repulping at a higher concentration showed more rapid defibering kinetics. Increasing the rotational speed of rotor at the optimum repulping concentration accelerated the defibering kinetics while it also led to higher fines generation and faster decrease in drainage property of the produced pulp. Hence, an alternative way was suggested: starting repulping at a conventional rotor speed and then accelerating the rotor speed for the last minute(s) of repulping.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.4
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• pp.38-44
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• 2007

In order to utilize unsorted ONP, which contains leaflets (printed coated papers), to produce pulp mold, optimum conditions for a repulping process were investigated with a laboratory high consistency pulper. It was concluded that medium or high consistency pulping is necessary to accelerate the rate of deflaking of unsorted ONP. Considering flake content, fines content and pulping energy, the optimum conditions for the laboratory Helico pulper were 11% of repulping concentration and 3 min of repulping time. The repulping temperature shall be at least $30^{\circ}C$. Aging of paper slows down the rate of de flaking but in an actual pulp molding process its effect could be negligible.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.3
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• pp.36-40
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• 2007

It has been problematic to repulp the dry broke treated with permanent wet strength agents like PAE, UF and MF. Solution type GPAM has the benefit of easy repulping but it has problems of cocross-linking and tends to gel. Therefore, the product concentration must be lower than 10% to reduce the gel generation problem. We developed emulsion type GPAM by an inverse emulsion technology to resolve both the repulping problem with permanent wet strength agents and the stability problem of GPAM solution products.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.2
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• pp.16-24
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• 1997

This experiment was mainly performed with a biological treatment of laser printed paper using enzyme, We got the following conclusions : In the case of nonionic surfactant treatment, brightness, residual ink contents and several strength properties of deinked paper were excellent at the low dosage of cellulase 0.05%. When mixed cellulase and xylanase was used, yield was increased as the dosage increased up to 0.2%, but brightness was decreased at the same condition. In contrast, deinking efficiency of anionic type was reduced in terms of brightness, residual ink contents, and tensile strength. As flotation time was increased, yield decreased and brightness increased slightly. On the other hand, the addition of surfactant during repulping process showed better result than that during flotation process.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.2
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• pp.58-67
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• 2001

MOW (Mixed Office Waste) mainly consisted of photocopied paper is being recycled to produce tissue or fine paper products. Toner particles that are fused and set on paper surface in photocopying process turns into large and plate-shaped particles after repulping which prevents them to be removed effectively in flotation deinking. The immediate purpose of this study is to find the effective deinking technology that increases the recycling potential of photocopied papers for manufacturing tissue and fine paper products. In this study the effects of pulping temperature and the type of hydrophobic groups of nonionic surfactants on the deinking efficiency of photocopied paper has been investigated. Particle size distribution of the toner particles after pulping and flotation, brightness, yield and ash removal were investigated. The size of toner particles after pulping increased as the pulping temperature was increased. When pulping at the low temperature finer toner particles were generated, however, greater amount of toner particles was found to attach to the fiber. When the pulping temperature was greater than Tg of the toner, the amount of coarse hairy particles increased. When nonionic surfactants with a double bond in hydrophobic groups were used, toner removal efficiency, brightness and ash removal were increased. As the addition level of surfactant was increased, yield decreased rather sharply without improving brightness.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.11 no.1
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• pp.33-40
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• 2005

This study was carried out for effective utilization of recycling resources to investigate the repulping conditions of car air filter waste paper and to evaluate the application into corrugating medium papermaking by blending these repulped pulps. Car air filter waste paper was made of virgin BKP and it was dipped into phenol resin solution. It was well disintegrated by laboratory Valley beater with 10%(basis on oven-dried pulp weight) NaOH addition and defoamer usage. The optimal temperature, beating consistency and treatment time were mainly $40^{\circ}C$, 1% and $30{\sim}40$ minutes, respectively. Handsheets were prepared with various blending ratios between air filter recycled pulp and KOCC. In the case of $10{\sim}20%$ substitution with air filter recycled pulp, physical properties reductions as compressive strength and burst strength of sheets were lower than others. These results showed more favour than the partial substitution of KOCC for corrugating medium even though some strength reduction of paper. It was also observed that the waste water of air filter recycling was not affective to environmental problems.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.2
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• pp.1-12
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• 2002

Starch dissolved in paper-mill wastes, either as a result of poor retention on the paper web or recycling of surface-treated broke, was a major pollutant Laboratory tests were performed by using different kinds of starch as a surface treatment. It was concluded that the use of cationic starch can positively affect the level of starch dissolved in liquid effluents. When cationically modified starches were used for surface sizing, the starch was tightly bound to the paper fibers, it was not removed during the repulping of broke. The result of mill trial in fine paper manufacture for the application of low-viscosity cationic starches used in size press reduced COD load in the effluents and increased One Pass Retention. It had been found that when cationic starch used as a surface sizing agent, more starch was retained on or near the surface of the sheet than with conventional oxidized starches. Thus surface strengths and quality were improved. In addition it is possible to maintain the desired level of starch penetration into the fiber net and improve porosity, opacity and brightness. In contrast, in most cases, dusting problems are notably eliminated. Cationic surface sized starch improved black and color ink-jet print quality in terms of feathering and optical density of the print image. These improved properties were believed to be due to a combination of fiber bonding and surface orientation more uniform starch concentration on the paper surface was resulted. Moreover cationic charges in the paper surface lend themselves excellently to fix ink jet ink anionic in nature.