• 펄프종이기술
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• 제45권4호
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• pp.27-33
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• 2013

Manufacturing fabrics from dissolving cellulosic pulp is increasing in these days. For making high quality of cellulose-based fabrics, control of cellulose DP (degree of polymerization), its alpha cellulose content, its brightness, and its crystallinity are important. To process the cellulosic raw material, refining of cellulosic fibers is essential, and it is important to know if refining affects those important cellulose properties. The effects of PFI mill and Valley beater refining on the alpha-cellulose content, cellulose DP, crystallinity, and paper mechanical properties of wood and two different cotton fibers were studied. The results showed that PFI mill refining rarely affected those properties. Fibers refined by a Valley beater displayed a small reduction in fiber length in comparison with those refined by a PFI mill. However, the Valley beater refining method produced almost no changes in cellulose properties, either. The refining process seemed to have very little effect on the cellulose DP, crystallinity index, or alpha-cellulose content until the freeness decreased to around 300 mL CSF for wood and 100 mL CSF for cotton fibers, respectively. There were also no differences in tensile strength development in two refining methods.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 1999년도 Proceedings of Pre-symposium of the 10th ISWPC
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• pp.172-177
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• 1999

Effect of fiber treatment with cellulase (Liftase A40), and with two refining methods (Valley beating and impact refining) on wood fiber and handsheet properties were investigated at three refining levels (300, 400, and 500ml) for two furnishes (NBKP and LBKP). Part of the treated furnishes were classified by 150 mesh screen into fine-free fiber, and fines. Fiber length analysis, WRV, zero-span strength, and other handsheet mechanical properties were compared. The study showed that Liftase A40 lowered the zero-span and the folding endurance of both furnishes (NBKP much more and LBKP much less). Pretreatment with Liftase A 40 followed by refining significantly lowered the fiber length and refining energy to reach to the target freeness. Impact refining, which is done by hitting the fibers vertically with rod at 20% solid content, kept the fiber length increased WRV, and improved handsheet mechanical properties much more than valley beating. Properties of fines from different sources were compared in detail in the study.

• 펄프종이기술
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• 제32권4호
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• pp.58-65
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• 2000

Use of a pectinase during preparing handmade papers from bast fiber of paper mulberry(Broussonetia kazinoki Sieb.) was investigated in order to decrease cooking chemicals and environmental pollution. For this purpose, four kinds of commercial pectinases, Rapidase LIQ(RLP), Rapidase Press(RP), Rapidase C80L Max(RCM) and Pectinase SS Kyowa(PSK) were used. And the durability of handmade papers before and after pectinase treatment was determined. RP and PSK had higher pectinase activity ad lower cellulase activity. The bast fiber was not defibered when pectinase was used. In order to increase the efficiency of enzymes, the bast fiber were treated ammonium oxalate(AO) or $K_2CO_3$under mild conditions. The AO pretreatment with those produced by $K_2CO_3$. The RP treated pulps after mild $K_2CO_3$cooking of the bast fiber were defibrated more easily than untreated pulp. The handmade paper prepared with the RP treated pulps after mild $K_2CO_3$cooking has good strength properties such as breaking length and folding endurance. Also, it has higher durability on heat aging, though its brightness was slightly lower than that of untreated paper.

• 펄프종이기술
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• 제47권2호
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• pp.42-52
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• 2015

In this study, cellulose nanofibrils (CNF) were modified through carboxymethylation or TEMPO-mediated oxidation and their effects on ionicity and characteristics of sheet, film, and foam were investigated. Carboxymethylation was carried out on pulp fibers as a pre-treatment before preparation of CNF. The gel-like and translucent CNF hydrogel was obtained by grinding of carboxymethylated cellulose fibers. Carboxymethylated CNF film and freeze dried sheet showed higher transparency than that of untreated CNF. The CNF sheet with high strength and the CNF foam without large ice crystals were obtained by using the carboxymethylated CNF. TEMPO-mediated oxidation was carried out as a post-treatment of CNF. The zeta potential and charge demand of TEMPO-oxidized CNF were increased with an increase in oxidation time and addition amount of NaClO. The density of sheet made of TEMPO oxidized CNF was increased with the amount of oxidizing agent. The TEMPO oxidized cellulose nanofiber (TOCN) which was obtained from supernatant after centrifugation could be converted to transparent film.

• Journal of the Korean Wood Science and Technology
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• 제47권5호
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• pp.617-632
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• 2019

This study aimed to investigate the anatomical structure and fiber quality of four lesser-used wood species namely Benuang (O. sumatrana), Duabanga (D. moluccana), Pisang Merah (H. hellwigii), and Terap (A. odoratissimus). This study evaluated its suitability for raw material in pulp and paper manufacturing. The anatomical structure was observed macro- and microscopically. Macroscopic structures were observed directly to the wood samples, while microscopic characteristics were observed through microtome specimens. Fiber dimension was measured through macerated specimens and fiber quality was analyzed following the Rachman and Siagian's method. Results showed that these four timber species have similarity in the indistinct growth ring, diffuse porous in a radial pattern, rounded solitary vessel outline, 1 to 3 cells of ray width, deposits within the rays, fiber length, and cell wall thickness. Differences were found on vessel diameter, vessel grouping, vessel frequency, tyloses existence, type of axial parenchyma, and ray height. Based on fiber length and its derived values, the wood fibers of all species studied are suitable for pulp and paper manufacturing. They belong to the II quality class. The produced pulp and paper would have good quality, especially in tensile, folding, and tear strength. To promote their utilization, silviculture aspect of these four species has to be well understood.

• 펄프종이기술
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• 제36권4호
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• pp.25-32
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• 2004

Flocculation of fibers and its distribution in paper are related to flocculation mechanisms, retention and drainage. Relationship between flocculation mechanisms and physical properties of paper has not been fully studied. In this study, flocculation of fibers was investigated by changing microparticles for flocculation mechanism analysis. When fillers were not added, formation and strength were deteriorated by 100, 300, or 500 ppm of linear PAM (all L-PAM), All L-PAM + 1200 ppm inorganic microparticle (1200-IM), all L-PAM + 120 ppm organic microparticle (120-OM), all L-PAM + 1200 ppm organic microparticle (1200-OM) because of too much flocculation. When 5, 15, $25\%$ (od.w/w) fillers were added, retention and drainage process were not affected by the extent flocculation when 500 ppm L - PAM, 500 ppm L - PAM + 1200- IM, and 500 ppm L - PAM + 120 ppm OM were added.

• 펄프종이기술
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• 제44권6호
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• pp.21-27
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• 2012

The effects of fines contents in OCC stock on the wet pressing process were evaluated in this study. The fines were collected from the beaten OCC stock by using 200 mesh. The dryness of handsheet samples after the couch and after the 1st wet press were greatly affected by the fine contents of the OCC stock. The higher contents of fines resulted in the lower value in dryness but the higher value of density followed by the higher strength properties. The addition of the retention aids and the drainage aids on the OCC stocks showed the wet pressing efficiency were greatly affected by the fine contents rather than the addition of polymer additives. The increase in the fine retention by the polymer additives offset the improvement in the wet pressing efficiency originated from the polymer additives.

• 펄프종이기술
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• 제34권4호
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• pp.1-6
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• 2002

In order to simulate the actual wet-end process in papermachine, RDA, a novel handsheet former, was used and following results were obtained. While the addition of polyelectrolytes gives significant effect on fiber flocculation, increase of stock consistency influenced on the formation of RDA sheets greatly. In particular, the consistency increase from 0.3 % to 0.4% abruptly increased floe size of RDA sheet and it results in severe deterioration of paper strength. Stock consistency, therefore, should be regarded as the most important factor in the formation simulation with RDA and should be controlled as the first sequence of tuning the operating conditions of RDA to simulate correctly the target machine paper's formation.

• 펄프종이기술
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• 제34권4호
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• pp.16-21
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• 2002

It was observed that drying temperature and curing time in the paper coating process as well as Tg of the latex used as a binder, greatly affected the properties of the coated paper such as roughness, paper and print gloss, K & N ink drop, and ink set-off. The higher drying temperature induced faster water evaporation and change in binding density, which caused an increase in paper roughness, ink gloss and ink set-off, but decrease in paper gloss and K & N ink drop. The increased curing time promoted latex filming and redistribution of the binder in coating layer. This increased pick strength and ink gloss, but decreased ink trapping. Finally, the higher Tg of the latex showed the wider changing range of these properties.

• 펄프종이기술
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• 제33권2호
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• pp.81-86
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• 2001

The functions of food packaging are not only prevention from physical damage and loss during carrying and transportation, but also extension of shelf-life by adding antimicrobial substrate in packaging materials. Consumption of active packaging is gradually increasing. With different dosage of potassium sorbate(P.S.), the food preservative agent, antimicrobial papers were made by internal and external application of starch. The antimicrobial action of the paper was analyzed by the halo test and the shake flask method. The mechanical properties and strength were also measured. Antimicrobial papers adding P.S. showed higher values in tensile index than adding starch. The antimicrobial paper using starch showed similar microbe decreasing rate as that using P.S. Though microbe decreasing rate was 21.9%, it showed possibility to make antimicrobial paper using food preservative.