• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.295-303
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• 2006

The pulp yield was improved by about 4.5-5% when polysulfide (PS) and anthraquinone (AQ) were added to the kraft cooking liquor (white liquor). The exchange of the black liquor with fresh white liquor further increased the yield. The highest pulp yield was obtained when the PS cooking liquor containing 70% of total active alkali (AA) and 100% of AQ was used from the beginning of the reaction and the black liquor was exchanged with fresh white liquor containing the residual 30% of AA just after temperature reached $135^{\circ}C$. There was a good correlation between kraft pulp yields of a hardwood species and the ratios of the amount of xylose to glucose (X/G ratio), liberated by an acid hydrolysis of the pulps. However, the correlation was dependent on raw material wood species. Therefore, it is required in advance to establish a correlation between the yields and X/G ratios for raw material wood species of a target pulp in order to estimate pulp yield using X/G ratio. The X/G ratios of relatively high yield pulps showed higher values than those expected from the correlation. In a mill trial, the superiority of the PS-AQ isothermal cooking (ITC) process over the kraft ITC process was confirmed by examining X/G ratio of pulps obtained. The pulp yield in the PS-AQ ITC process was estimated at about 57.0%. This yield is very high, which indicates that reaction conditions of the PS-AQ ITC process are optimal.

• 환경생물
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• 제17권2호
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• pp.191-198
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• 1999

침엽수와 활엽수 펄프내의 리그닌(lignin) 제거 효과를 개선하기 위해 호알칼리성 균류인 Cephalospotium sp. RYM-202의 xylanase를 표백 전처리하고 이에 의한 펄프의 표백 증진 효과를 조사하였다. 두 종류의 펄프 모두 5$0^{\circ}C$에서 효소반응을 수행하였을 때 펄프내 xylan의 가수분해가 가장 높게 나타났다. 펄프내 xylan의 가수분해를 위한 효소의 최적 pH는 8.0이었으며, pH 9.0에서도 최대활성의 90%이상이 유지되었다. 각각의 펄프 재료에 효소를 전처리한 결과 표백(리그닌 제거)과정의 증진 효과를 보였으며, 침엽수와 활엽수의 kappa number는 각각 3.7과 2.0 ISO units 만큼 감소되었다. 아울러 효소처리 혹은 효소 미처리 펄프를 각각 표백한 후 수초지를 제조하여 종이의 물성을 상호 비교한 바, 효소처리는 종이의 섬유 구조에 큰 영향을 끼치지 않는 것으로 나타났다. 이러한 결과들은 호알칼리성 Cephalospotium sp. RYM-202의 알칼리내성 xylanase가 알칼리 조건하에서의 펄프 전처리 과정에 매우 적합함을 의미한다.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2011년도 춘계학술발표회 논문집
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• pp.169-169
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• 2011

Xylans are polysaccharides present in large amounts in cell walls of land plants. However, during kraft cooking, a high portion of hemicelluloses including xylans are dissolved in the cooking liquor. In the current trend for a more effective utilization of biomass, attention has been paid to the exploitation of xylans as strength-enhancing additives for paper. It is believed that surface xylan adds flexibility to the cell wall/fiber surface, resulting in stronger fiber-fiber joints or greater contact area between the fibers. Accordingly, there is proposal for a new pulping process involving the extraction of xylan prior to pulping, followed by their re-adsorption on the unbleached pulp. A suitable bleaching process should be employed then, which ought to does not only improve the brightness of the pulp, but also remain the effect of the adsorption of xylan on pulp fibers. The objective of this research was to investigate the impact of hydrogen peroxide bleaching on the properties of unbleached hardwood kraft pulp pretreated with birchwood xylan by measuring optical properties (brightness, post color number, opacity) as well as physical properties (tensile index, tearing index, bulk) of handsheets made from the bleached pulp. In the meantime, the influence of process variables of peroxide bleaching including bleaching temperature, time, initial pH and $MgSO_4$ dosage were studied.

• 펄프종이기술
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• 제42권2호
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• pp.35-40
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• 2010

Variations in hexeneuronic acid content in hardwood alkaline pulps were investigated to evaluate their contribution to kappa number. Out of diverse chemical pulps the highest hexeneuronic acid content were measured in yellow poplar kraft pulping, which was assumed to enhance ca. 7.0 of kappa number determined by acid permanganate consumption. In yellow poplar soda-anthraquinone pulping, hexeneuornic acid was contributed to increment of 5.0-6.0 kappa number. In eucalyptus alkaline pulping, hexeneuronic acid content was not significantly different from soda-anthraquinone pulping. Increment of Kappa number by hexeneuronic acid was 4.5-5.6 depending on pulping method and pulping time at target temperature.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2000년도 춘계학술발표논문집
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• pp.39-46
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• 2000

In pulp and papermaking process, enzymatic treatment of pulp fibres has been a topic of increasing interest in last decade. Lots of patents, papers and research reports were published on the application of enzymes in the fields of enzymatic bleaching, deinking, slime control, pitch control, waste water treatment and fibre modification. Cellulase and hemicellulase are the principal enzymes used for the modification of fibre property. This study was carried out for determinating the behaviors of enzyme to pulp fibres. A commercial enzyme, Denimax BT which is consisted with cellulase and hemicellulase, was treated to the kraft pulp produced from domestic hardwood mixtures. Results were mainly concentrated on the behaviors of freeness, drainability and fines content of fibres, and physical properties of paper with enzyme treatment. The freeness levels and dewatering ability were developed, and the fines contents were decreased. The creation of fines were controlled by the method of pre-enzyme treatment prior to fibre beating. The mechanical strength of paper, like tensile, burst, tear strength and folding endurance, were remarkably improved by the pre-enzyme treatment.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.331-336
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• 2006

The aim of this work was to inhibit the heat-and moisture-induced yellowing of ECF/TCF bleached hard wood kraft pulp (HBKP) retaining hexenuronic acid (HexA). We have already reported that one of the derivatives of HexA, 5-formyl-2-furancarboxylic acid (FFA), causes yellowing of HBKP in acidic paper, and that FFA might polymerize or react with pulp components to form new chromophoric groups (1). In this study, it was shown that the carboxylic base of FFA interacts with that of glucuronic acid or galacturonic acid, resulting in strong yellowing. Therefore, it seems that preventing the reaction of carboxylic bases could be effective in suppressing this yellowing. We have discovered that polycarboxylic acids (for example, citric acid, tartaric acid, etc.) are useful as a yellowing inhibitor.

• 펄프종이기술
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• 제33권1호
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• pp.30-37
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• 2001

The effects of enzymatic treatment of recycled fiber were investigated to obtain the basic informations which can be used to improve the papermaking properties of recycled fiber. The recycled fibers were prepared by the repeated handsheet making and disintegrating of hardwood of hardwood and softwood kraft pulp. Novozym 342, Dinimax and Pulpzyme HC were used for enzymatic treatment. The change of fiber length distribution, freeness, contact angle and crystallinity of pulp were measured. The brightness, opacity, breaking and tear index of paper were also measured. The enzymatic treatment decreased long fiber fraction of recycled hardwood fiber, but increased long fiber fraction of recycled softwood fiber. Freeness was decreased with 0.1% enzyme and then increased again with the increase of th enzyme dosage. The improvement of flexibility of recycled fiber was obtained through the decrease of contact angle that is resulted from the decrease of crystallinity of fiber. Brightness and opacity were affected by the type of pulp and enzyme, and dosage of enzyme. Breaking length of recycled hardwood fiber was improved with enzyme treatment, but breaking length of recycled softwood fiber was decreased except for 0.01% Pulpzyme treatment. Tear index was decreased with enzymatic treatment and the lowest decrease was observed with the treatment to Pulpzyme.

• 펄프종이기술
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• 제46권3호
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• pp.50-57
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• 2014

In this study, we investigated the physical properties of kraft pulps made from rice husk, peanut husk and garlic stems. These agricultural byproducts were collected individually, and then various pulps were manufactured from them by controlling active alkali, sulfidity, reaction time and the liquor ratio in the kraft pulping process in order to analyze the applicability of these agricultural byproducts as raw materials for kraft pulps. After kraft pulping, we measured yield, flake content, fiber length, fiber width and freeness of pulps, and the fiber shapes of the pulps were observed by using an optical microscope. When the higher active alkali, longer reaction time and lower liquor ratio were applied in kraft pulping process, reject content decreased and fiber yield increased. The pulp from garlic stems had the longest fiber length and that from rice husk showed the highest intial freeness. All of the pulps from agricultural byproducts showed higher initial freeness, shorter fiber length and the similar fiber width compared to OCC, BCTMP and hardwood BKP. The fibers of the pulps made from agricultural byproducts showed a similar shape to those of commercial pulps. It was concluded that these agricultural byproducts had a potential as raw materials to produce an alternative pulp to the commercial pulps.

• 펄프종이기술
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• 제44권4호
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• pp.99-107
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• 2012

In this study, the lumen loading technology for preparing magnetic papers were evaluated. The rice husk fiber, softwood kraft pulp, hardwood kraft pulp were applied and the morphological properties of pits on the those fibers were investigated with SEM. The softwood kraft pulp had the bigger size of pits, $3{\sim}5{\mu}m$ in diameter, which resulted in higher loading amount. The comparison of two methods for lumen loading such as the low concentration method with the disintegrator and the high concentration method with the Hobart mixer showed the Hobart mixer could resulted in the higher efficiency. The conditions of lumen loading process such loading time, addition amount of metal particles and addition of PEI were also evaluated. The magnetic hysteresis loop of handsheet samples made of lumen loaded fiber with $Fe_3O_4$ and $Fe_2O_3$ were examined. The differences in magnetic properties could be found according to the ferrite types.

• 한국인쇄학회지
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• 제19권1호
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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.