• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.85-90
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• 2006

Increasing the filler content of sheet improves the optical properties and printability of paper and provides an opportunity for saving production cost through fiber replacement with relatively low-priced filler. But increasing the filler content tends to decrease the strength of paper and filler retention. It also tends to deteriorate drainage on the paper machine. To overcome these problems, preflocculation technology of fillers may be employed. Many research efforts have been made on the properties of preflocculated filler, namely prefloc, whose size and size distribution were influenced by polymer type and shear level. But there is much to be investigated about the effect of the prefloc characteristics on the physical properties of paper. To evaluate the effect cationic polymers on the size and size distribution of preflocculated GCC and their shear stability, cationic PAM and cationic starch were used. The influence of the preflocculation on filler retention and its surface distribution, and the changes of physical and optical properties of handsheets affected by the characteristics of preflocs were examined. Filler distribution on sheet surface was also analyzed by EPMA. Results showed that cationic PAM formed large preflocs at low dosage. Cationic starch was required to add 15 times as much as cationic PAM to obtain the preflocs with similar size. But preflocs formed with cationic starch was superior in shear stability to those formed with cationic PAM. Filler preflocculation technology could provide an opportunity of increasing filler content significantly without loss in tensile strength. And increased filler contents could compensate brightness loss which often accompanies filler preflocculation. When excessively large preflocs were used, however, brightness loss rather than the improvement in tensile strength was predominant. Therefore it is of great importance to produce preflocs with proper size and shear stability for maximizing the improvement of physical properties of papers.

• 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.45 no.4
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• pp.1-8
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• 2013

High loading of printing and writing grades with fillers has many advantageous aspects in papermaking because it allows decreasing fiber use and reducing manufacturing cost. High loading technology, however, has some disadvantageous aspects as well. It decreases physical properties of papers, especially strength properties. The problem associated with high loading can be reduced by applying surface sizing starch solution onto paper surface. It is important to control the penetration of the surface sizing starch solution into paper web to obtain the desired property improvement. In this study, the effect of the addition of two polymers into starch solution on paper properties has been examined. PVOH and polyDADMAC were used as polymeric additives for surface sizing with oxidized starch. Viscosity of starch solutions and surface roughness of dried starch films on glass slides showed that some interactions between polymeric additives and oxidized starch have been occurred and the most extensive interaction with starch solution was obtained with high molecular weight polyDADMAC. Low molecular weight PVOH was most effective in improving folding endurance and internal bond strength. On the other hand, polymer addition showed no effect on surface strength of paper. This indicates that not the level of starch holdout but the bonding strength of starch itself has predominant influence on surface strength of paper.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.4
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• pp.21-27
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• 2001

Korean traditional paper (Hanji) making technology has adopted two kinds of sheet forming processes, which called "Oebal-choji": and "Ssangbal-choji". The sheet forming process of Oebal-choji is an original method developed in Korea. At first, paper stock is dipped onto the mold and flow away in the forward direction. Then, paper stock is scooped again and rhythmically rocked from side to side, this work is repeated several times. Through this operation the fibers intertwine and paper layers are formed. Ssangbal-choji is almost same as the Nagashizuki, which used in Japan. In this method, paper stock is scooped onto the mold and rhythmically rocked backwards and forwards several times, the water drains slowly through the bamboo screen and then sheet is formed. Tamezuki method is used in Japan and China. This is a method in which the mold is dipped into the paper stock once and left to drain. In the Ssangbal-choji and Nagashizuki methods, the most of excess solution is cast out while in the Tamezuki all of it is allowed to drain through the mold. This study was carried out to investigate the physical properties of the Hanjis that were made by Oebal-choji, Ssangbal-choji, Nagashizuki, and Tamezuki sheet forming processes. The results were follows; Physical properties of the Oebal-choji Hanji were better than those of Ssangbal-choji, Nagashizuki, and Tamezuki. Oebal-choji Hanji made little difference of paper strength between MD and CD, but Ssangbal-chjo and Nagashizuki Hanjis made wide difference. And there are no difference of paper strength between MD and CD on the Tamezuki Hanji. On the confocal laser scanning microscopy (CLSM) observation of the Hanjis, Oebal-choji made well crossed fiber orientation than those of other forming processes.r forming processes.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.4
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• pp.15-20
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• 2001

The function of the moisture-proof paper is to prevent moisture from adsorbing into the packed goods. Water-vapor transmission rate of the moisture-proof paper should be less than 100g/$m^2$.24hr and the optimum rate would be less than 50g/$m^2$.24hr. In general the moisture-proof paper has been made by laminating polyethylene or polypropylene on top of the base paper. However this kind of moisture-proof paper has a problem in recycling so that it brings about environmental pollution. In general the moisture-proof paper has been made by laminating polyethylene or polypropylene on top of the base paper. However this kind of moisture-proof paper has a problem in recycling so that it brings about environmental pollution. The purpose of this paper was to make moisture-proof paper using the mixture of SB latex and wax emulsion which was recyclable and environmentally friendly. Water vapor transmission rate showed less than 50g/$m^2$.24hr in mixture ratio of 85:15, 87:13, 90:10. Especially the mixture ratio of 87:13 showed the most favorable water-vapor transmission rate. However, the moisture-proof layer was destroyed slightly by folding in packing. It has been observed that there was no close relationship between water-vapor transmission rate of the moisture-proof paper and grammage of the base paper, but the density of base paper had influenced on water vapor transmission rate. It was also observed that the moisture-proof paper could be recycled. The moisture-proof paper was similar to base paper in degree of the pulping, and there was no significant difference in dispersion between moisture-proof paper and base paper. Most of wax particles which caused the spots during drying process could be removed by flotation process. Tensile strength and tear strength of both moisture-proof paper and base paper after pulping were measured to examine the fiber bonding, and no significant difference in physical properties was observed.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.6
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• pp.123-129
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• 2015

There are two kinds of cartons for beverage packaging, one is aseptic brick (AB) type and the other is gable top (GT). In this study, AB and GT were used as a raw material of recycled paper to investigate the recyclability at their varied blending ratios. Fiber consistency at pulping decreased as the blending ratio of AB increased. As a result, a lot of fines were generated from AB and flakes from GT increased because shear force in pulper decreased. Bulk of handsheets was more than $2.0cm^3/g$, and ISO brightness decreased as the blending ratio of AB increased. The best condition to recycle beverage cartons is to discriminate each cartons separately because of differences in the composition. However, there are problems such as the limit of the collection system and social costs. Therefore, it is assumed that the blending ratios of AB should be adjusted at less than 20% for effective recycling of beverage cartons.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.1
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• pp.125-131
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• 2002

When a tooth is fracture with the pulp exposure, and if a fragment is large enough to save, reattachment of the fragment would be a choice of treatment and reattachment of the fragment provides several advantages over other forms of dental restoration following crown fracture. For the purpose of tooth reattachment, it is important to preserve the sound enamel around fracture area. For young patients, tooth reattachment has more advantages in the sense that they recover faster and that it enables other treatments at the same time. Through the continuous advancement in adhesion technology and the effort for aestheticism, various reattachment methods have been practiced and more efforts are considered necessary. The presented cases are that we had practiced in our department in Kyung Hee Medical center, I may address that fragmentation has been successfully done with aesthetically fine results, and no pathologic changes were found in short term follow-ups.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.4
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• pp.69-76
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• 2012

The bamboo fibers from three Korean bamboo species, Moso, Henon and Timber bamboo, were prepared by disintegration after thermal treatment. The samples were prepared according to the age of growth; bamboo shoots, 20 days and 50 days of growth. The fiber quality was also investigated by morphological and chemical analyses. There was no big difference in the dry mass of fibers among the three bamboo species. However, the dry mass of fibers from 50 days of growth was increased by 34%, whereas it was ranged in 9-20% in the case of fibers from bamboo shoots and 20 days of growth. In the results of morphological analysis, the fibers could be classified as the fibers from metaxylem, the fibers from parenchyma and the fines produced during disintegration. The fibers from 50 days of growth were separated from metaxylem, whereas the fibers from bamboo shoots and 20 days of growth were mainly consisted of fibers from metaxylem and parenchyma. The chemical analysis of fibers showed that the contents of carbohydrates, lignin and extractives were not much affected by thermal treatment.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.44 no.4
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• pp.51-61
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• 2012

The new alkali pulping process combined with electron beam treatment was applied to utilize hemp bast tissues as a new valuable fibrous resource. Hemp bast tissues have some chemical properties with high lignin contents and holocellulose not to be defiberized by alkali pulping only, compared with the bast tissue of paper mulberry. To make up for the weakness of traditional alkali pulping process, electron beams were directly irradiated into the swelled bast tissue of hemp in NaOH solution and distilled water, and then facilitated the defiberization of hemp bast tissues. The papermaking from hemp bast fibers manufactured by the combination pulping process showed good apparent density, formation structure and air permeability, and had some mechanical properties with lower tensile, tear, burst strength and folding endurance. It is finally concluded that the combination pulping process with electron beam treatment could be suggested a new alternative for non-woody fibers.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2000.04a
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• pp.49-49
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• 2000

최근, 제지산업에 있어서 종이의 경량화 연구는 원료 절감, 에너지 절감 등의 주 효과와 운송비 절감을 비롯한 부차적인 효과가 크기 때문에 앞으로도 활발히 추진 될 것으로 전망 된다. 그러나 이러한 경량화는 종이의 광학적 특성인 불투명도와 물리적 특성인 강도 저하 를 필연적으로 가져오게 한다. 특히 인쇄 및 필기용지의 경우 종이의 불투명도 저하는 인쇄 시 인쇄화상 뒤비침 현상으로 인하여 치명적인 악 영향을 초래한다. 종이의 불투명도를 개선하기 위하여 사용되는 가장 보편적인 방법은 충전제를 가능한 범 위내에서 많이 첨가시키는 것이다. 그러나 이 방법은 불투명도는 향상이 가능하나 미세분의 다량 발생에 의한 초지공정의 보류 및 폐수 문제, 종이의 강도 저하 문제를 야기 시킨다. 따라서 본 연구는 종이의 경량화에 수반되는 불투명도, 강도 문제의 지료 영향 인자인 섬유, 종이구조 및 충전제의 특성 등을 검토하여 보다 효율적인 지료조성 대책을 제시하고 충전제 첨가법을 개선하여 보류율을 향상시키고, 종이의 강도 감소율을 최소화하면서 불투 명도를 향상시킬 수 있는 효율적인 방법을 제시하기 위하여 수행 되었다. 구체적인 방법으로서는 펄프 및 충전물의 종류에 따른 종이의 물성과 불투명도의 변화를 관찰하였으며 또한 충전물의 충전시, 충전물의 보류를 향상시키면서 섬유간의 결합 방해를 최소화 시켜 종이의 본래 강도를 유지시키는 Fiber Loading의 새로운 방법인 Beater L Loading법을 시도하였다. 본 연구의 결과 수종간의 차이는 있었지만 활엽수 펄프가 칩엽수 펄프에 비해 불투명도 및 백색도 등의 광학적 성질이 우수한 것으로 나타나 펄프 종류및 수종의 적절한 선택에 의 하여 종이의 광학적 성질을 어느 정도 높일 수 있음을 알 수 있었다. 그리고 충전물을 Beater Loading에 의해 첨가하였을 경우가 일반적인 Loading보다 보류 율이 좋았고 종이의 불투명도와 강도도 높게 나타났었다. 이러한 실험결과로 보아 일반적인 Loading 방법보다 Beater Loading법이 강도의 손실없이 불투명도를 높일 수 있는 효과적인 수단이 될 것으로 생각된다.