• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.36 no.3
• /
• pp.9-14
• /
• 2004

The useful fungi which secret extracellular enzymes was selected for deinking agent of old newsprint. Five fungal strains were isolated from a paper mill soil ground. The CMCase, FPase and xylanase activities of fungi on the liquid culture were investigated at optimal growth conditions. The results of this study were as follow: The optimal pH and temperature for culture growth were 4～8 and 27～$35^{\circ}C$, respectively. For screening of extracellular enzymes at optimal culture conditions the optimal culture period were less than 6-7 days. Fusarium pallidoroseum and Aspergiilus niger which shows relatively higher CMCase, FPase and xylanase activities than the other species were selected for further enzymatic deinking research.

• Clean Technology
• /
• v.10 no.4
• /
• pp.195-201
• /
• 2004

Cellulase was modified with copolymer with polyethylene(PE)/polypropylene(PP) oxide and maleic anhydride(MA) by maleylation reaction, and modified cellulase was applied to the reprocessing of old newsprint (ONP). Cellulase of modified cellulase enhanced the detachment of ink particles by fibrillation of fiber. The copolymer, which acted as the surfactant formed bubbles and removed the ink particles in the floatation process. Modified cellulase showed the same deinking ability without excess dosage compared with the conventional method. And, it improved the physical properties including tensile strength, brightness, and whiteness compared with the conventional deinking process. The bond between the ink and fiber got stronger as the storage time increased, and it became very difficult to remove the ink particle. But, modified cellulase increased the deinking ability by 41% compared with the conventional process at the experiment of the ONP for 1 year storage time. It removed the yellowing and increased the whiteness and brightness as well as tensile strength and internal bond strength.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.47 no.3
• /
• pp.40-46
• /
• 2015

For some Korean newsprint mill, addition level of aluminum sulfate has been reduced because sulfur from aluminum sulfate has detrimental effect on the efficiency of anaerobic water treatment. At this moment, an unexpected decrease in sizing degree of TMP mixed newspaper was occurred. The phenomena means that hydrophobic substance usually originated from TMP cannot be fixed on the paper. This study focused on effect of alum and PAC on sizing of paper and contamination. Also, substitutability of PAC was discussed as a possible alternatives of aluminum sulfate under anaerobic condition of water treatment. Evaluation of sizing degree and pitch deposit potential were performed at the varied addition level of PAC and aluminum sulfate. Hydrophobic substance mainly derived from TMP could be fixed on the surface of fiber by PAC. Fines retention was not changed by replacing aluminum sulfate with PAC. Additionally, fixing of hydrophobic substance without excessive agglomeration can be enhanced by PAC with low molecular weight. Consequently, sizing degree of newspaper and contamination of recycling process of ONP can be controlled by low molecular weighted PAC.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.37 no.1 s.109
• /
• pp.25-37
• /
• 2005

This study was carried out to examine the optimal cultural condition in enzyme activities of CMCase, FPase and xylanase in selected strains which secret extracellular enzymes for using deinking agent to old newsprint. The results of this study were as follow: The production of enzyme by Bacillus pumilus I was maximal as grown on the medium, containing of rice bran+xylan $2.0\%$, peptone $0.8\%,\;K_2HPO_4\;0.1\%\;and\;CaCl_2\;0.06\%$ at pH 8.0 and $28^{\circ}C$ for 72 hours. Optimal cultural condition of B. subtilis I was avicel+xylan $3.5\%,\;urea\;0.4\%,\;K_3PO_4\;0.1\%\;and\;CaCl_2\;0.015\%$ at pH 9.0 and $28^{\circ}C$ for 36 hours. The maximal enzyme production was observed in the medium, containing of avicel+xylan $3.5\%,\;urea\;1.6\%\;and\; K_2HPO_4\;0.125\%$ with pH 9.0 when B. pumilus II was cultured at $28^{\circ}C$ for 60 hours. The production of enzyme by B. subtilis IT was maximal as grown on the medium, containing of xylan $2.0\%,\;yeast\; extract\;0.6\%,\;K_2HPO_4\;0.1\%\;and\;ZnSO_4\;0.04\%$ at pH 8.0 and $34^{\circ}C$ for 36 hours. The activities of FPase and xylanase in tested 4 strains were not much different with Thermomonospora fusca.

• 제어로봇시스템학회:학술대회논문집
• /
• 2002.10a
• /
• pp.88.1-88
• /
• 2002

$\textbullet$ Introduce $\textbullet$ Basic principle and kinematics model of the AGV $\textbullet$ Design of the guidance system $\textbullet$ Simulation and experimentation $\textbullet$ Conclusion

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.45 no.3
• /
• pp.52-58
• /
• 2013

To evaluate the anisotropic characteristics of Korean traditional paper-Hanji, the physical and mechanical characteristics of hand-made hanji, and machine-made hanji were investigated in this research. The densities of copying paper and newsprint paper appeared to be two times higher than the densities of hand-made hanji using Ssangbal sheet forming and hanji made of paper mulberry fiber. The breaking length, and tear index of both Hanji using Owangbal sheet forming, and hand-made Hanji using Ssangbal sheet forming appeared to be different according to the directions in paper. The breaking lengths of Hanji using Owangbal sheet forming showed little differences according to the directions. Breaking length of Hanji using Ssangbal sheet were slightly higher than those of Hanji using Owangbla sheet forming. The breaking lengths of machine-made hanji, copying paper, and newsprint paper were two to four times higher than those of hand-made Hanji. The breaking length showed higher differences according to the direction than the tear index. The tensile strength according to the directions in paper showed significant differences (${\alpha}$=0.05) in all papers used in this research.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.32 no.2
• /
• pp.26-34
• /
• 2000

Understanding the nip geometry and heat transfer phenomena of soft nip calenders, which has been used in the production of newsprint and coated papers for many years, is very important since improper setting of soft nip calendering conditions causes deterioration of paper quality and productivity. In this study theoretical analysis on nip pressure and heat transfer phenomena in the nip of soft nip calenders has been made. The variables examined were calendering pressure, surface temperature of the heating roll, nip residence time and ingoing sheet moisture, By measuring nip widths and maximum nip pressure with Prescale film at a normal temperature, accurate line load has been obtained. With this line load, nip pressures at different temperature and nip widths were calculated. Results showed that as temperature increased, nip widths increased and nip pressures decreased. Equations derived for the heat conduction phenomena in soft nip calender nip were derived based on the semi-infinite plate and finite difference method and were used for the analysis of heat transfer within the nip. Temperature profiles in z-direction of paper within the nip were obtained. Finite difference method allowed more accurate analysis of the heat transfer in the calender nip. In this study newsprint and coated paper were considered as a single plate and two-layer plate consisted of sheet and coating layers, respectively. Heat trans-fer to paper increased as heated roll surface temperature and nip residence time were increased.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.36 no.3
• /
• pp.60-66
• /
• 2004

The effects of roll diameter, winding time, winding methods and relative humidity on curl In newsprints(46$g/m^2$, 54 $g/m^2$, and 54 $g/m^2$ SNC) are examined. The larger MD curl appears at smaller roll diameter, with the extension of winding time, and at the treat ment of soft nip calendering. The MD curl shows the back side curl at winding methods with top side as outer side(TSO), and the top side curl with top side as inner side(TSI). While the CD curl in newsprints( 46 $g/m^2$, and 54 $g/m^2$ SNC) treated with calender is hardly influenced by the storage times, roll diameter, and winding methods. However the CD curl in newsprint(54 $g/m^2$) gradually increases to a two weeks, and then hold constant regardless of roll diameter and winding methods.. The CD curl shows always the top side curl regardless of winding methods. At high relative humidity, the CD curl largely reduces, but the MD curl is not nearly changed. Especially, the CD curl in news-prints(54 $g/m^2$ SNC) is little affected by the changes of relative humidity.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 1999.04b
• /
• pp.296-301
• /
• 1999

Different papers such as toilet and towel tissue, newsprint and copy paper made from reclaimed fibres were characterized using UV-VIS reflectance and fluorescence spectroscopy. The emission properties of the extracts of the papers were also evaluated. Photochemical irradiation at ambient temperatures, and thermal aging of the copy papers at 105$^{\circ}C$ and 150$^{\circ}C$ were performed. Post-colour numbers (PC) were calculated from the reflectance values measured from the corresponding UV-VIS reflectance spectra. Light absorption coefficient spectra were calculated before and after irradiation, and the changes in absorption coefficient were related to the content of chromophores in the papers. Photochemical and thermal discolouration of the copy papers, similar to that of virgin fibres, was readily observed. The influence of changes in the concentrations of fluorescent brightening agents and dyes on the spectral properties was also assessed. Photostabilization studies of the copy papers were performed with the use of polymer additives polyethylene glycol (PEG) and polytetrahydrofuran (PTHF).

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2006.06b
• /
• pp.381-386
• /
• 2006

Many different types of bleaching chemicals and processes have been globally used for deinked pulp. Besides chlorine-free bleaching chemicals, hydrogen peroxide, and sodium dithionite that could be used without restriction for almost all types of fibers, chlorine-containing chemicals such as chlorine dioxide and sodium hypochlorite have also used throughout the world. Even though hydrogen peroxide is commonly used in newsprint, it could not effectively increase brightness. Experimental evaluation on the possibility of using formamidine sulfinic acid (FAS), a reducing agent, for bleaching a wood-containing deinked pulp has been carried out in this study. The effect of bleaching efficiency for FAS on operational conditions and chemical concentrations compaired to hydrogen peroxide in one and two stages was studied. FAS bleaching showed higher brightness at high temperature and low consistency, and vice versa for peroxide one. Bleaching with sodium silicate and DTPA in FAS and peroxide stage showed better results than cases without them. Sodium silicate and chelant seemed minimize the influence of transition metal ions, including manganese and iron ions, which induce both bleaching agents to decompose. As a result, FAS as a reducing agent seems more effective than hydrogen peroxide for increasing brightness and reducing yellowness. FAS and FAS sequence seemed more efficient than the other two stages of bleaching sequences with regard to the best brightness level obtained. When bleaching was conducted with FAS, COD load was just about one-third compared to peroxide, and brightness stability of the bleached pulp appeared better than peroxide after UV light irradiation.