• 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.18-25
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• 2005

The mechanical strength is the prime requisite for linerboard and corrugating mediums. Repeatedly recycled OCC fibers show less suitable property for papermaking mostly due to hornification and reduced fiber length. To overcome these problems many researches including fractionation, enzymatic treatment, and chemical or mechanical treatments of fibers have been carried out. In this study, the effect of mechanical treatment by high consistency pulping on the characteristics of recycled fibers as well as mechanical properties of sheets were investigated. Results on the strength properties of handsheets made of recycled fibers that were treated to same freeness level by beating and high consistency pulping, respectively, showed that beating treatment was more efficient in improving strength. Drainage and recycling potential of the fibers treated by high consistency pulping, however, were expected to be superior to beating because fines content and fiber length didn't change significantly.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.2
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• pp.5-12
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• 1998

Exploitation of the papermaking technology to reduce the strength loss that accompanies when using recycled papers as raw materials for papermaking is one of the most important issues imposed upon today's paper industry. Multi-layer sheet forming technology has been suggested as a way that provides some answers to this issue. In this study strength properties of single- and two-layer handsheets formed with recycled fiber and unbleached softwood kraft pulp have been examined to quantify the benefits when using two-layer sheet forming technology rather than a conventional single layer sheet forming precess. Single- and two-layer handsheets were made from 50% of OCC and 50% of Sw-UKP and their strength properties were evaluated. Also the strength properties made from Sw-UKP and OCC sheets were determined. A multihead, which can be attached on the top of hand- sheet former, was used to form two-layer sheets. Maximum strength properties could be obtained in the freeness range of 500∼300mL CSF for Sw-UKP Most of the strength properties was reduced by 30∼35% when 50% OCC was blended with UKP. Decrease of strength properties, however, could be reduced by employing a two-layer sheet forming method. Creator strengths could be obtained when UKP was positioned at the top layer of two layered sheets indicating greater UKP fines retention due to the filtration effect of the OCC layer formed prior to UKP layer contributed the strength improvement. Two-layer sheet showed lower Scott internal bond strength than single layer sheet. By incorporating some of UKP fibers into OCC layer this reduction could be reduced.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.3
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• pp.91-98
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• 2016

Linerboards have been produced by recycling recovered paper such as old corrugated containers(OCC). Usually linerboards produced during summer season show weak strength compared with those of produced during winter. In order to cope with the weak strength of linerboards produced during summer, and to confirm uniform quality, it is important to understand the seasonal effect on strength properties. Effect of pulping temperature of the OCC for linearboard production was investigated by controlling pulping temperatures at $18^{\circ}C$ and $51^{\circ}C$. Low pulping temperature ($18^{\circ}C$) caused more generation of fines in stock. Consequently retention and drainage of linerboard defibrated at high pulping temperature ($51^{\circ}C$) were better than those of $18^{\circ}C$. Strength properties of handsheet at low pulping temperature were higher than those of high pulping temperature and it could be confirmed that low pulping temperature during winter is one reason of seasonal variation of recycled linerboard strength. It is considered that surface modification of OCC fibers by harsh pulping action during winter caused increase of paper strength.

• 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.