• 펄프종이기술
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• 제35권5호
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• pp.10-16
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• 2003

Presence of small amount of old newspapers printed with waterbased flexographic inks leads to a significant loss of brightness of the deinked pulp by flotation process. Recently there has been an increased interests in employing neutral deinking processes to solve the problems associated with waterbased flexo ink. A comparative experimental study was performed to evaluate the efficiency of neutral deinking and conventional alkaline deinking for ONP furnishes contaminated with flexo ink. Effects of the deinking processes on pulp quality and white water characteristics were examined. It was shown that neutral deinking would provide significant improvement in brightness, yield, and freeness as compared with conventional alkaline deinking. There was no increase in brightness when OMG was added in the furnish up to 20 ％, and it was attributed to the redeposition of flexo inks on chemical pulp fibers.

• 펄프종이기술
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• 제38권4호
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• pp.31-40
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• 2006

Presence of old newspapers printed with waterbased flexographic inks leads to a significant loss of brightness of the deinked pulp by flotation process. It has been shown that neutral or acidic flotation deinking has many advantages in recycling of flexo printed newsprints. A comparative experimental study was performed to evaluate the deinking efficiency of three alcohol type deinking agents in flotation deinking of flexo printed newspapers. Zeta potential of neutral deinked pulp was less negative than alkaline deinked pulp. Also neutral deinking was advantages in reducing turbidity, COD, and cationic de-mands of deinking process water.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2010년도 춘계학술발표회 논문집
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• pp.7-7
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• 2010

Flotation deinking is a common practice for removing ink from recovered paper, and it is becoming a key process in many recycling paper mills. Flotation deinking was successfully introduced to the paper recycling industry in the 1980s, and its applications in wax removal, stickies control, and fiber fractionation have attracted great research interest. A successful flotation process has three major efficient subprocesses: the detachment of the ink particles from the fibers, the effective adhesion of the ink particles onto air bubble surfaces, and the removal of froth and ink particles from flotation cells. Surfactants can affect these subprocesses either positively or negatively. To understand how a surfactant can positively and negatively affect the flotation deinking process, the basic chemistry of surfactant in solution should be discussed.

• 펄프종이기술
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• 제31권2호
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• pp.86-91
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• 1999

A new test method has been developed for a quantitative evaluation of macro-stickies in recycled pulps. The method uses a fine slot screen to separate a sticky particles form fiber in the pulp samples. The obtained sticky particles were spread on filter paper and covered with silicon carbide powder in order to make the stickies area with sufficient contrast between stickies and background. The stickies are then counted by a scanner-based image analysis system. The validity of this evaluation method of stickies of KOCC, ONP and white ledger wastepaper recycling plants respectively. It is shown that this method can be applied for a quantitative determination of stickies content in various recycled pulp samples. With this testing method, reproducible and reliable data were obtained for the actual mill pulp samples.

• 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.291-295
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• 1999

Coprinus cinereus 2249 that is a kind of basidiomycetes constitutively produced alkaline carboxymethyl cellulase (CMCase), filter paper cellulase (FPase) and xylanase. Crude enzymes prepared with optimal conditions showed higher FPase activity than CMCase activity. The FPase was most active at pH 9 at 50$^{\circ}C$. When applied on deinking of the old newsprint (ONP), it increases the freeness and brightness due to effect of hydrolysis at 0.1% enzyme concentration. Also, The physical properties of deinked pulp were improved.

• 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.343-348
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• 1999

Presence of small amount of old newspapers printed with waterbased flexographic inks leads to a significant loss of brightness of the deinked pulp by flotation process. Recently there has been an increased interests in employing neutral deinking processes to solve the problems associated with waterbased flexo ink. A comparative experimental study was performed to evaluate the efficiency of neutral deinking and conventional alkaline deinking for ONP furnishes contaminated with flexo ink. Effects of the deinking processes on pulp quality and white water characteristics were examined. It was shown that neutral deinking would provide significant improvement in brightness, yield, and freeness as compared with conventional alkaline deinking. Three was no increase change in brightness when OMG was added in the furnish up to 20%, and it was attributed to the redeposition of flexo inks on chemical pulp fibers.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2007년도 추계학술발표논문집
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• pp.21-33
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• 2007

CPAM has been applied to the paper industry for the purpose of wet-end improvement for a long time. And molecular weight and charge density have been managed most important quality factors to make CPAM for this application. Recently branched CPAM was developed to improve retention and drainage characteristics and we considered branch degree of CPAM as important factor as molecular weight and charge density. In this experiment, we tried to investigate physical and chemical properties to determine branch degree and flocculation efficiency using Arbocell pulp which was recently developed micro size pulp and finally we applied retention and drainage test under the ONP stock condition.

• 펄프종이기술
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• 제35권4호
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• pp.23-33
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• 2003

The possibility of real time analysis about hot melt resins and pressure sensitive adhesives in newsprint stock was investigated by performing comparative tests using conventional image analysis method and real time contaminants analyzer. Based on the test results, the performance of real time contaminants analyzer in terms of detecting primary stickies in newsprint stock could be verified. Real time stickies analysis showed good precision and over-estimation of hot melt resins and under-estimation of pressure sensitive adhesives could be corrected by adapting new method. Real time analysis of primary stickies in the actual newsprint stock also showed good correlation with conventional image analysis and the performance of real time contaminants analyzer could be verified again. Adjustment of the contrast sensitivity of real time contaminants analyzer was enough to set the proper monitoring conditions for primary stickies in newsprint stock.

• 펄프종이기술
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• 제33권3호
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• pp.24-28
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• 2001

The utilization of wastepaper as a papermaking raw material is everlastingly required for the environmental protection of earth. However the recycling of wastepaper for this purpose cause another problem such as the increasing of the load of wastewater treatment, lower strength properties of paper, and poor printability, etc. The interest in the development of the environmentally friendly deinking technology is increased continuously. Thus, our research team have tried to apply the ozone to the deinking of white ledger and ONP, and obtained the positive results which can be considered as an alternative method for the conventional deinking method. The purpose of this study is to investigate the mechanism of ozone deinking. Styrene acrylate and polystyrene were treated with ozone and measured the change of molecular weight with the GPC. The molecular weight distribution obtained with GPC showed only slight increase by the ozone treatment, and gel formation by the polymerization was observed. Therefore the removal of ink particles with ozone treatment seems to be facilitated by the increase of the brittleness and decrease of adhesive property.

• 펄프종이기술
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• 제42권5호
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• pp.24-30
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• 2010

Papermaking technology has drastically improved over the last 20 years to face new challenges. Because environmental regulations have become increasingly strict, papermaking systems have had to accommodate elevated recycled pulp content and an increased use of recycled process water. Process water in papermaking systems has become more dirtier and reduced polymer efficiency. Amphoteric PAM demonstrated a higher degree of stability in a high conductivity environment compared to cationic PAM. This was illustrated by the improved retention performance, particularly the ash retention. This amphoteric polymer can be used for board or newsprint production using recycled pulp, especially for the systems where polymer dissolving water is high in conductivity and degradation of cationic functional groups of cationic PAM can occur.