• 펄프종이기술
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• 제37권5호통권113호
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• pp.41-49
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• 2005

This paper deals the effect of anthraquinone (AQ) on the contribution of sulphidity in kraft pulping of sapwood. The pulping conditions namely- active alkali concentration, pulpingtime, temperature and liquor ratio were varied in low ($15\%$) and high ($30\%$) sulphidity. $0.1\%$ AQ was added in the low and high sulphidity pulping with varying active alkali concentration and cooking time. At optimum conditions, low sulphidity kraft process produced about $44\%$ pulp yield with kappa number of about 23. But in high sulphidity kraft process kappa number was reduced to about 20 at the same yield. An addition of AQ reduced alkali requirement by $2\%$ on oven dried raw material and cooking time by 1 hour to produce pulp yield of about $44\%$ at kappa number 20. AQ is more effective in low sulphidity pulping than the high sulphidity pulping. The breaking length of kraft-AQ pulp was slightly higher than that of kraft pulp.

• 펄프종이기술
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• 제41권5호
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• pp.20-25
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• 2009

Residual extractives had a noticeable impact on the brightness of unbleached hardwood kraft pulps (trembling aspen). The brightness-impacting extractives were effectively removed by oxygen delignification. In addition, oxygen delignification was more effective in removing chromophores in hardwood unbleached kraft pulps than in those of softwood (loblolly pine). The residual extractives in unbleached hardwood kraft pulps also affected the pulp color, primarily redness and the L value. These redness-related extractives in unbleached hardwood kraft pulps were also effectively removed by oxygen delignification. There were no significant color differences between untreated and solvent-extracted oxygen-delignified aspen kraft pulps. The residual extractives in unbleached and oxygen-delignified softwood (loblolly pine) kraft pulps did not have a significant impact on either brightness or pulp color.

• KSBB Journal
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• 제16권2호
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• pp.179-182
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• 2001

Horseradish peroxidase(HRP) 및 $H_2O_2$. 와 함께 2, $2^+$-azinobis (3-ethylbenzthiazoline-6-sulfonic acid)(ABTS)블 라디 칼 전달체로서 사용하면 kraft 펄프의 표백효율이 증가하였다. 이때 반 응에 사용할 수 있논 $H_2O_2$의 농도는 약 20 mM까지 증가시킬 수 있었다 Kraft 펄프의 표백효율은 효소의 사용량을 0 0.3 mg/90 mL 까지, ABTS의 농도를 2 mM 까지 높일수록 증가하였으나 이후에는 더 이상 증가하지 않았다. 또한 HRP 에 의한 펄프표백 효율은 효소의 활성 및 펄프에의 홉착강도 와 멸접한 관련이 있었다. HRP의 활성과 kraft 펼프의 표백 효율은 pH 7에서 가장 높았으며 산성용액과 암쌀려성 용액 에서는 강소하였다. 또한 HRP의 펄프홉착 강도는 pH 6-8에 서 가장 낮았고 산성용액(pH 5) 및 알칼리성 용액(pH 9)에서 가장 높았다 펼프의 주요구성 성분인 결정형 셀룰로즈와 려 그닌 중 려그년에 대한 효소의 흡착강도가 더욱 높았다.

• 펄프종이기술
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• 제38권3호
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• pp.13-22
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• 2006

The analogs of cyclic hydroxamic acids containing N-OH group have been proposed to play effective laccase-mediators in kraft pulp bleaching with laccase/mediator system. The existing mediators (NHA, 1-HBT, VA), the best laccase-mediators reported so far, and selected several analogs of cyclic hydroxamic acids were evaluated as a laccase-mediator for kraft pulp bleaching. It was found that NHA was the most effective mediator for the Trychophyton sp. LKY-7 laccase (TrL) in kraft pulp bleaching with TrL/mediator system, increasing about 10% ISO of brightness and decreasing about 2.8 of kappa number after alkaline-peroxide bleaching. Of the cyclic hydroxamic acidstested, the NHP.1(N-hydroxypyridone analog) was shown to enable TrL to effectively degrade lignin in kraft pulp bleaching, demonstrating approximately similar effect with that of NHA. However, the effect of substituent patterns of cyclic hydroxamic acid analogs in kraft pulp bleaching was not observed. The inhibitions of NHA and NHP.1 on TrL were not exhibited in TrL/mediator system. As a new mediator for TrL, NHP.1 was considered to be able to use in kraft pulp bleaching with TrL/mediator system.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 Pre-symposium of the 10th ISWPC Recent Advances in Paper Science and Technology
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• pp.232-238
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• 1999

The reinforcement of wheat straw pulp sheets with softwood kraft was studied, with special emphasis on the impact of softwood kraft beating and the proportion softwood kraft in straw pulp. the reinforcement was evaluated by measuring the tensile stiffness sand in-plane fracture behavior of samples. the results were compared with a mechanical pulp (TMP) and with a hardwood birch kraft, both reinforced with the same softwood kraft. Wheat straw pulp forms strong interfiber bonds. Therefore, its tensile stiffness and tensile strength are larger than TMP used. In-plane tear tests showed that a pure wheat straw pulp sheet has low fracture energy and correspondingly a narrow fracture process zone. The fracture energy of the reinforced straw sheets was found to increase linearly with the proportion of both unbeaten and beaten softwood pulps.

• 펄프종이기술
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• 제45권4호
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• pp.16-20
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• 2013

Yellow poplar grown in Korea and imported eucalyptus were compared their kraft pulping characteristics and evaluated the replacing possibility of eucalyptus by yellow poplar. Difference between yellow poplar and eucalyptus were investigated in chemical composition and fiber morphology. Yellow poplar kraft pulp resulted in the higher yield, longer fiber length and thicker fiber, and higher pulp strength than that of eucalyptus. More xylan survived in eucalyptus than yellow poplar during kraft pulping, which led to similar pulp yield even though polysaccharides in Eucalyptus was 4.5% less than in yellow poplar. Longer and thicker yellow poplar pulp fiber resulted in better beating response and pulp strength properties.

• 한국포장학회지
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• 제5권2호
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• pp.38-41
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• 1999

This study was carried out to investigate improvement of kraft paper sack mixed with recycled paper for sugars and assorted feeds. Four Plies of kraft paper mixed with recycled paper(basis weight : $80g/m^2$) were taken place of two plies of kraft paper made from all pulp(basis weight : $98g/m^2$) and one ply of kraft paper mixed with recycled paper(basis weight : $80g/m^2$) for sugar 30kg. Three Plies of kraft paper mixed with recycled paper(basis weight : $80g/m^2$) were taken place of two plies of kraft paper made from all pulp(basis weight $98g/m^2$) for sugar 15kg and assorted feed 25kg. Physical properties, tensile strength, internal tearing strength and bursting strength, were improved by exchanging kraft paper mixed with recycled paper for kraft paper from all pulp and so kraft paper sacks made from all pulp were no damage in handling. They had so high friction coefficient that there was no danger of collapse on pallet by slipperiness in transportation and handling. And they had high printability so disappearance of printing by the contact with other paper sack in transportation was not found.

• Biotechnology and Bioprocess Engineering:BBE
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• 제2권2호
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• pp.94-96
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• 1997

A xylanase was purified from a commercial crude xylanase, Pulpzyme HC, and used for the bleaching of kraft pulp in the absence or in the presence of nonionic surfactants, Tween 20, Tween 80, and Igepal C930. The purified xylanase has a molecular weight of 23,500 as determined by a reducing SDS-PAGE. Tween 20 was most effective to enhance the efficiency of the enzymatic bleaching of kraft pulp by xylanase.

• 펄프종이기술
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• 제41권4호
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• pp.52-57
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• 2009

Soda and kraft pulping experiments were carried out in order to investigate the pulping characteristics of bamboo grown in Vietnam. The merit of kraft pulping was not observed for bamboo pulping from the viewpoint of delignification and screened pulp yield. The improvements of delignification during soda and kraft pulping of bamboo were observed by the addition of AQ. The bamboo pulp leaded the bulkier structure than those made from SwBKP and HwBKP. The average fiber length was 1.62mm which is shorter than those of SwBKP, but longer than those of HwBKP. It was found that the physical properties of bamboo pulp sheet could be varied by the pulping method, cooking condition, AQ addition, bleaching and refining etc.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.2
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• pp.285-290
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• 2006

As an alternative method to solve air pollution problem and difficulty of pulp bleaching of kraft pulping process, NaOH-Urea pulping was applied. The properties of NaOH-Urea pulp were compared to those of NaOH and kraft pulps. Addition of urea in low alkali charges retarded delignification rate compared to NaOH pulping. But, in high alkali application, delignification was significantly enhanced not from the addition of urea but from the high alkalinity. It was disclosed that urea did not participate on delignification reaction by the experiment using lignin model compound. Compared to paper strengths at the same level of sheet density, NaOH-Urea pulp gave as almost same breaking length and tensile index as those of kraft pulp. Especially tensile energy absorption and burst index were higher than those of kraft pulp.