• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.2
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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.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.2
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• pp.67-74
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• 2010

This study was carried out to investigate the pulping and papermaking characteristics of lotus (Nelumbo nucifera G.) leafstalk for the development of high performance paper. Anatomical and chemical properties of the lotus leafstalk were analyzed. The pulping and papermaking properties of the lotus leafstalk by conventional alkali and sulfomethylated pulping processes were also evaluated. The length and width of fibers were 0.06-3.32 mm (av. 1.23 mm) and 3.47-25.6 ${\mu}m$ (av. 20.7 ${\mu}m$), respectively. The length and width of vessel elements were 0.07-0.78 mm (av. 0.20 mm) and 14.1-330.0 ${\mu}m$ (av. 54.13 ${\mu}m$), respectively. The fiber length/fiber width ratio was 60.20. The extractives (cold water, hot water, 1% NaOH and ethanol-benzene) and lignin content of lotus leafstalk were higher than those of plant bast fiber. The contents of holocellulose, lignin, and ash were 73.8%, 24.3%, and 4.3%, respectively. The pulp yields based on pulping methods were sulfomethylated pulping av. 52%, and alkaline pulping av. 42%. The conventional alkaline pulping shows better pulp and sheet properties than the sulfomethylated pulping which was modified pulping processes. But the sulfomethylated pulping shows higher brightness than alkali pulping. In the consequence of FE-SEM observation, lotus leafstalk pulp consists of various kinds of thin walled fibers which have large amount of small pits.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.3
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• pp.34-42
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• 1997

This study was carried out to investigate the proper cooking conditions of soda-anthraquinone and alkaline sulfite-anthraquinone pulping of rice-straw, and get basic data f9r the use of rice-straw chemical pulp through the test of characteristics and physical properties of pulps made in the various cooking conditions From the experimental results , we can conclude as follows. In the soda-anthraquinone pulping of rice-straw, the optimum cooking conditions were 60 min. at $150^{\circ}C$ in the amount of caustic soda of 20% with the addition of anthraquinone(0.05%). And total yield, Kappa No. and brightness of pulp made in the condition above mentioned were 41.9%, 7.7 and 51.1 respectively. In the alkaline sulfite-anthraquinone pulping of rice-straw, the proper mixing ratio of cooking chemical(caustic soda : sodium sulfite) was 50:50. And the optimum cooking conditions were 60 min. at $150^{\circ}C$ in the amount of cooking chemical of 20% with the addition of anthraquinone(0.05%). At that time, the total yield, Kappa No, and brightness of pulp were 50.1%, 9.1 and 40.2 respectively. As a result, the alkaline sulfite-anthraquinone pulping was superior to the soda-anthraquinone pulping in the aspect of yield, but inferior in the viewpoints of Kappa No. and brightness. For the comparison of qualities of pulps made in the various cooking methods and conditions, the physical properties of four sorts of pulps were tested. As a result, soda-anthraquinone pulps were superior to alkaline sulfite-anthraquinone pulps in the various strengths excluding tear strength and brightness. On the other hand, pulps made in the condition of addition of cooking chemical of 20% were superior to pulps in the dosage of 15% in the aspects of all the strengths and brightness.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.40 no.2
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• pp.57-64
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• 2008

In general, the entire of paper mulberry bark, which is not cut into pieces with an appropriate length, have been used in the pulping. This kind of pulping method couldn't accomplish the improvement of beating and sheet forming efficiency. For this reason, we investigated the effects of the cutting length of paper mulberry bast fiber on pulping and Hanji (Korean traditional paper) properties, in order to develop high quality Hanji manufacturing process. The cutting length variation of paper mulberry white bast did not great effects on pulp yields. The pulp yields based on pulping methods were sulfomethylated pulping av. 57.4%, alkali-hydrogen peroxide pulping av. 55.4%, and alkaline pulping av. 53.5% respectively. The optical properties such as brightness, opacity, scattering coefficient, and absorption coefficient were slightly improved by the increase of paper mulberry white bast cutting length. The increase of paper mulberry white bast cutting length resulted in poor sheet formation. Physical properties such as breaking length, TEA, tear index, burst index, and folding endurance were slightly improved by the increase of cutting length. The modified pulping processes, which used sulfomethylated method and alkali-hydrogen peroxide method, showed better pulp and sheet properties than conventional alkaline pulping.

• Journal of the Korean Wood Science and Technology
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• v.34 no.5
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• pp.104-110
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• 2006

We investigated why aspen extractives are more resistant in kraft pulping than pine extractives. Residual extractives content in aspen kraft pulps were 0.5~1.1% compared with 0.1~0.2% in pine pulps. This different response arises from the different composition of extractives in wood chips. Resin acids in pine were almost completely removed in kraft pulping but those are not existence in aspen. Slower saponification of aspen steryl esters resulted from different chemical structure of aspen steryl esters. Main sterols in aspen steryl esters were 24-methyl cyclolanostenol which was highly resistant to alkaline hydrolysis with its characteristic steric hindrance. Sterols in aspen were not well removed in kraft pulping. The relative composition of sterol in aspen kraft pulps was increased with increasing pulping time. The presence of fatty acids in aspen kraft pulps is considered to unusual. Fatty acids in alkaline are supposed to be well ionized and removed well in the washing stage. Nevertheless, there were significant amount of fatty acids remaining in aspen kraft pulps.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.2
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• pp.31-39
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• 2011

The applicability of arrowroots as materials for paper manufacture was investigated by evaluating the characteristics of arrowroots pulping and pulps, and the surface characteristics of paper made of arrowroots. The results is as follows. The yield of grounded pulp, alkaline pulp, grounded bleach pulp, and alkaline bleach pulp are 98.0%, 37.7%, 84.8%, and 32.5%, respectively. The extraction components in arrowroot's fibers was shown high in 1%-NaOH extraction. The amount of holocellulose and lignin were largely decreased, but a slight decrease was shown in the bleaching processes. Many shivers were shown in the grounded fibers. The amount of shivers was decreased and the single fibers were increased during the process of bleaching. The alkaline pulp and the alkaline bleach pulp showed high in the beating time and freeness than the grounded pulp and grounded bleach pulp. The conditions of sheet surface according to beating time is effected largely by the conditions of original pulp.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.4
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• pp.56-63
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• 2010

Microcrystalline cellulose (MCC) was prepared from Miscanthus in this study. Two pulping methods, soda pulping and alkaline sulfite pulping were applied as a pretreatment process. After pulping, two different bleaching processes such as $ClO_2$ treatment followed by $H_2O_2$ treatment and $O_3$ treatment followed by $H_2O_2$ treatment were carried out. Two concentration of $H_2SO_4$, 47% and 57% were applied to the purified Miscanthus cellulose as a acid hydrolysis process to make MCC. The crystallinity index and morphological properties of the produced MCC were evaluated with X-ray diffractometer and scanning electron microscopy. The MCC originated from the soda pulping sample showed the higher crystallinity index than that originated from the alkaline sulfite pulping sample. The two stages of treatmen twith $O_3$ and $H_2O_2$ resulted in the higher purified cellulose products.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.1 s.109
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• pp.47-52
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• 2005

Enzymatic pulping properties of mixed office waste paper in standard disintegrator were investigated for successful enzymatic deinking of mixed office waste paper. Enzymatic pulping need more revolution in standard disintegrator than alkaline pulping and Cellusoft need more revolution than Denimax. The freeness of disintegrated pulp with enzyme was higher than those of disintegrated pulps with alkaline and heat killed enzyme. The freeness of disintegrated pulp with Denimax was higher than that of disintegrated pulp with Cellusoft. The freeness of disintegrated pulps were increased with a dosage of enzymes. The mechanical properties of disintegrated pulp were improved with enzyme addition comparing with heat killed enzyme. The tensile and burst index of hand sheet of disintegrated pulps with acidic Cellusoft were higher than that of others.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.1
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• pp.100-110
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• 2016

Alkaline Peroxide Mechanical Pulping (APMP) of Pinus densiflora harvested from domestic mountains was explored. APMP contributes to various advantages including pulp quality, elimination of the need for a bleaching process, and energy savings. Sequential treatment of impregnation of bleaching chemicals and refining not only overcome the concern of alkaline darkening of wood chips during chemical impregnation, but it also brightens the chips to the desired brightness levels suitable for writing and printing papers. APMP pulping from Pinus densiflora was greatly influenced by the dosage levels of hydrogen peroxide and sodium hydroxide. Alkaline peroxide treatment was carried out by applying one of three levels of hydrogen peroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips) and one of three levels of sodium hydroxide (1.5, 3, and 4.5% based on the oven-dried weight of the wood chips). Other chemicals including a peroxide stabilizers and metal chelation were constantly added for all treatments. Chemical treatment with a liquor-to-wood ration of 9:1 was carried out in a laboratory digestor. Compared to BTMP, APMP pulping displayed outstanding characteristics including the less requirement of refining energy, the better improvement of tensile strength, the more reduction of shives, and the greater increase of pulp brightness. In particular, when 4.5% of hydrogen peroxide with impregnation during 90 minutes was used, the brightness of APMP reached 64.9% ISO. Even though bulk of APMP was decreased with the increase of sodium hydroxide, a better and improved balance could be achieved between optical and strength properties. The spent liquor obtained from the discharge of the impregnation process at the dosage level of 4.5% hydrogen peroxide exhibited an equal level of residual peroxide with BTMP. In conclusion, APMP pulping showed successful results with Pinus densiflora due to its better response to the development of optical and physical properties compared to TMP pulping.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.1
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• pp.75-82
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• 2013

The traditional Hanji-making was confronted with lots of industrial disadvantages and economic problems, due to the original hand-made process. Recently, the studies on the automation of overall Hanji manufacturing process is carried out by applying the commercial chemical pulping method in order to expand industrial application or efficiency of non-wood fibrous materials. However, the application of commercial pulping methods to the bast tissues of paper mulberry leads to the chemical and mechanical deterioration of cellulosic fibers. In this study, the optimal cooking method using the bast parts of paper mulberry produced by an auto-scraping device was applied to minimize the damage of fiber strength for the paper yarn manufacture. The pre-steaming treatment and alkaline pulping systems were evaluated in removal efficiency of lignin and pectin materials within the bast tissue of paper mulberry. With the application of pre-steaming treatment and 2 stage pulping system using potassium carbonate and then sodium hydroxide, kappa values were decreased two times more in lignin removal than the single stage of pulping method. It was also identified from SEM images and ATR-FTIR spectra that the pectin components within cellular structure of bast tissue were easily removed and the debarked bast parts by a auto-scraping device were easily defiberized by 2-stage pulping sequence using potassium carbonate/sodium hydroxide pulping system.