• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.5
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• pp.27-35
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• 2008

In order to determine the most appropriate recycling line to treat old corrugated container (OCC) to substitute unbleached kraft pulp (UKP) for the manufacture of kraft paper, three recycling lines were evaluated in pilot scale tests. The recycling line consisting of kneading, flotation, washing, dispersion and screening steps was able to produce pulp with acceptable appearance. Kneading was shown to be more efficient treatment to reduce specks than dispersion. In addition, 0.2 mm slot screen was very effective to remove specks. Severe damages on fiber morphology such as shortening of fiber and formation of fines were not observed during mechanical treatments such as kneading and dispersion. Most of strength properties of the kraft paper produced with the recycled pulp were found to be slightly increased after treated in the recycling lines.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.4
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• pp.85-90
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• 2012

Wet pressing process has great influence not only on the paper properties but also on the efficiency of total manufacturing process including energy efficiency. The slow drainage propensity of old corrugated container(OCC) might require more complicated control of wet pressing process. In this study, the change in press efficiency and in structure of wet sheet by the various condition of laboratory roll press simulator were evaluated to provide background information about wet pressing of OCC. The higher pressure and the slower machine speed resulted in higher efficiency of wet pressing but the change trends of dryness depending on the wet press pressure and machine speed were shown differently according to OCC treatment. The effects of water contents of felt on the wet press efficiency and sheet structure were also investigated. The higher contents of water in felt resulted in less removal of water generally and the crushed structure of wet sheet were appeared especially at higher pressure.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.6
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• pp.94-102
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• 2014

The physical and chemical properties of recycled fibers from mixed waste paper are more and more deteriorated because of unknown history of recycling times. In order to improve the mechanical properties of liner paper, the recycled fibers from wasted cotton clothes were used in papermaking process, and their applicabilities were evaluated in several points of fiber modification. Thus, two kinds of fiberizing methods from waste cotton clothes were considered by using rotary sandpaper and grinder mill. Finally, the rotary sandpaper method was relatively desirable in preserving longer fiber length and fibrillated fiber surface. The recycled cotton fibers by swelling treatment with NaOH and bleaching with reductive chemicals were mixed with OCC fibers, and the handsheets were prepared to basis weight of $80g/m^2$ and evaluated the mechanical properties of paper. The fibrous properties showed outstanding results in freeness and WRV improvements by alkali treatment and high brightness by reductive bleaching treatment. The physical and mechanical properties of sheet by mixing OCC fibers and recycled cotton fibers were also highly improved in tensile, burst strength and specially folding resistance.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.2
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• pp.77-82
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• 2011

The changes in the wet pressing response of old corrugated container(OCC) stock depending on the beating treatment and the addition of polymer aids were investigated with laboratory roll press instrument. Two types of polymer aids, such as high molecular weight polymer with low charge density and low molecular weight polymer with high charge density, were applied in this study. The more beaten OCC stock showed the lower dryness after wet pressing. The addition of polymer aids had great influences on the wet pressing efficiency and paper properties. The dryness after wet pressing was increased by the addition of polymer aids, but the pattern of changes in dryness were different depending on the type of polymer and the properties of stock. The higher molecular weight polymer aids showed the greater increase in the dryness. The properties of paper such as air permeability, bulk, formation, tensile strength were also greatly affected by the addition of polymer aids.

• Journal of the Korean Graphic Arts Communication Society
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• v.19 no.1
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• pp.64-74
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• 2001

This study is to find the effect of the molecular weight distribution of components on the freeness and physical properties of paper by observing the change of properties according the modification of fibers by using production technology and process technology together to develop additives which can effectively control according to the purpose of paper-making process and by combining low molecular weight cellulase (below MW 20,000; CMC activity 400 unit) with different enzyme's molecular weight and activity and high molecular weight cellulase(MW 20,000∼80,000;CMC activity 90,000 unit) and then process them in Sw-BKP(Softwood Bleached Kraft Pulp) and Hw-BKP(Hardwood Bleached Kraft Pulp) and Cotton Linter Pulp and OCC(Old Corrugated Container) with different properties of pore of surface of fibers respectively, since it is judged that making the appropriate composition ratio of components is necessary in consideration of the properties of fibers and paper-making process.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.32 no.1
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• pp.10-18
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• 2000

To improve the physical properties of OCC (Old Corrugated Container) fibers, we used the mechanical pre-treatment on the fibers before refining . The mechanical action in the Hobart mixer induced high shear and compression on the fibers, which resulted in changes of fiber internal structure, and microcompressions on the surface of the fibers. We evaluated the amount of mechanical treatment on the fibers by fiber curl index for convenience. Four different refining techniques were applied to the pre-treated fibers (valley beater, Kady mill, PFI mill, and Impact refining) to find the best combination of the pre-treatment and the refining methods. Conclusions were summarized as followed. 1. Mechanical pre-treatment in Hobart mixer for more than 1 hour caused the increase of curl index of OCC fibers, and increased breaking length, burst index, and tear index the handsheets more than 10 % in this experiment. 2. Kady mill and PFI mill refining were effective in keeping fiber length from shortening Kady mill and Valley beater refining straightened out the fiber curls, and reduced the curl index. 3. Valley beating reduced fiber length very fast and generated fines more than other refining methods. 4. To increase breaking length and burst strength while keeping tear strength , combination of mechanical pre-treatment and Valley beating were most effective.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.5
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• pp.98-103
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• 2015

The reduction of the energy consumption in papermaking process become more important issue because of the regulation of green house gas (GHG) emission. Since more than half of energy for papermaking process is consumed during drying process, the increase of the drying efficiency would be very important solution for saving energy and reduction of GHG emission. The improvement of drying efficiency could be very difficult for the liner board mill because the liner board are usually made of recycled paper, OCC (old corrugated container). The short fiber and fines originated the OCC lead to compact sheet structure and delay the water flow out during wet pressing process and drying process. The application of lignocellulose spacer could provide more loose wet sheet structure and result in the higher drainage rate and the improved drying efficiency. In this study, the effects of the application of lignocellulose spacer to the liner board mill were evaluated based on the mill trial. In order to overcome the common disadvantage of the spacer, the loss of strength properties, the spacer was pretreated with amphoteric polyelectrolyte during mill trial. The results showed the application of pretreated spacer improved the drying efficiency by reducing steam consumption. And the loss in the strength properties by the spacer could be supplemented by the pretreatment.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.5
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• pp.61-68
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• 2014

The energy efficiency of papermaking process becomes more significant because of various new regulation of the energy consumption and the green house gas emission. In this study, the effects of wood powder addition on the drainage and the drying efficiency of the OCC based paper products, linerboard, were deeply investigated for improving energy efficiency. The fractionation of wood powder depending on the size were conducted. The bigger size of wood powder resulted in the higher bulk and the higher drainage efficiency, but the lower paper strength. The drying efficiency were in detail evaluated depending on the drying process level. In the first section of drying process until the 80% solid level, there were no significant changes in the drying efficiency by the addition of wood powder. However, after the 80 % solid level, the drying efficiency was greatly improved by the addition of wood powder. Those results showed the addition of wood powder could greatly affect not only the drainage in forming and wet pressing but also the drying process.

• Korean Journal of Agricultural Science
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• v.26 no.1
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• pp.21-30
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• 1999

To increase the strength properties of recycled fiber, especially OCC (Old Corrugated Container) in this study, we used the mechanical pretreatment on the fibers before refining. The mechanical action in the Hobart mixer induced high shear and compression on the fibers, which resulted in the breakdowns of fiber internal structure, and microcompressions on the surface of the fibers. We evaluated the degree of mechanical treatment by fiber curl index. Four different refining techniques were applied to the pretreated fibers (Valley beater, Kady mill, PFI mill, and Impact refining) to find the best combination of the pretreatment and the refining methods. Conclusions were summarized as followed. 1. In keeping the fiber length from shortening, Kady mill and PFI mill refining were effective. Kady mill and Valley beater application tended to straighten out the fiber shapes. 2. Valley beating increased the breaking length of the handsheets better than other methods, while lowering the tear strength most. The mechanical pretreatment increased breaking length about 10% in average irrespective of four different refining methods. 3. Tear strength was increased by the mechanical pretreatment and by the PFI mill refining. 4. Burst strength was increased by the mechanical pretreatment and by valley beating method. 5. In increasing the breaking length and burst strength while keeping tear strength, combination of mechanical pretreatment and Valley beating were most effective.