• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.6
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• pp.98-105
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• 2015

Demands of thermal recording paper have been increased significantly by increase in usage of invoice, fax, and label. Thermal recording paper was mainly made based on virgin fiber. It is necessary to find a suitable alternative to virgin fiber in terms of environment protectional resources conservation. In this paper, deinking properties of different recovered papers were analyzed in order to use the recovered paper as raw material of thermal recording paper. Recovered paper were ONP, OMG and white ledger. Flotation reject of OMG was high because inorganic pigments in coating layer could be removed by upstream of froth. Brightness of white ledger and OMG were much higher than that of ONP. Therefore, properties of pulp made from the recovered paper could be enhanced with increase in blending ratio of white ledger and OMG. However, blending ratio of OMG caused the increase of flotation reject. Consequently, the optimum blending ratio of ONP, OMG, and white ledger was 3:3:3 for eco-friendly thermal recording paper. Under the condition, brightness was about 70% and ERIC was below 300 ppm.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.5
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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.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04b
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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.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.4
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• pp.34-41
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• 2003

The effect of wettability of deinking agents which formed with various nonionic surfactants against the pulp fibers and ink particles were studied, And the effect of flotation processes on the deinking were also investigated. The wettabilities of the deinking agents against the water and ink particles were measured by Washburn tube and sessile drop techniques, respectively. As the water absorption increased (i.e., hydrophilicity increased), the ink removal increased, which indicates that the ink removal is strongly affected by the detachment process due to the swelling of the pulp. Also, when the contact angle of air/ink/deinking agent increased, the hydrophobicity of the ink particles increased, the efficiency of the ink removal and the brightness increased.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.729-736
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• 2016

It is necessary to recycle and reuse waste paper for preservation of the global environment. Instead of a solid deinking agent, liquid deinking agents have been made using various fatty acids with EO/PO added for higher deinking effect. The removal efficiency of ink on waste paper was evaluated by the ERIC and brightness properties after processes of recycling pulping (sample composition ONP: OMG = 5:5, concentration 15%, temperature $45^{\circ}C$, pulping time 20 min.) and flotation (concentration 1%, temperature $45^{\circ}C$, air flow 7 L/min, time 8 min.). Also, the ink reattachment of paper was evaluated by hyperwashing. The results show that it is effective for mass-preparation to saponify oleic acid with KOH at $80^{\circ}C$ and to add EO/PO. This deinking agent was used in a paper plant, and we evaluated the brightness, color, and ERIC. The deinking agent showed excellent performance.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.1
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• pp.1-7
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• 2001

The immediate purposes of this study is to establish the surface chemical principles associated with the flotation process of waste papers and to verify them by practical flotation experiments. To achieve this AKD sized hydrophobic microcrystallince cellulose (MCC) with different levels of hydrophobicity, and hydrophilic MCC dyed with black were prepared as model substances. The effects of surface characteristics on flotation efficiency were evaluated by measuing the brightness of the flotation rejects obtained after the flotation experiments carried out using MCC mixtures prepared with different ratios of hydrophobic and hydrophilic MCCs. Results showed that more than 90% of the flotation rejects consisted of hydrophobic MCC indicating the critical importance of the hydrophobicity of the materials in the flotation process. The proportions of hydrophobic materials in the reject remained constant when highly sized MCC was used as a model of hydrophobic substance.

• Current Research on Agriculture and Life Sciences
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• v.22
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• pp.49-56
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• 2004

Cellulolytic enzymes were prepared from alkaline resistant microorganisms which were newly screened from calcic soil. Characteristics of enzymes and enzymatic deinking efficiency of wastepaper were investigated. The results were summarized as fellows: 1. The recovery rate of crude enzyme was 93.7% in Bio-B and 57.4% in Bio-F. 2. The protein content in crude enzymes was lowest and the thermal stability of crude enzymes was highest in Bio-F. 3. The brightness gain of Bio-F deinked pulp was best in ONP and Bio-B deinked pulp was best in MOW. 4. The reject yield was increased with enzymatic deinking flotation process. 5. The residual ink area of paper was increased with enzymatic deinking and large size of ink particles were remained in paper.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.29 no.2
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• pp.16-24
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• 1997

This experiment was mainly performed with a biological treatment of laser printed paper using enzyme, We got the following conclusions : In the case of nonionic surfactant treatment, brightness, residual ink contents and several strength properties of deinked paper were excellent at the low dosage of cellulase 0.05%. When mixed cellulase and xylanase was used, yield was increased as the dosage increased up to 0.2%, but brightness was decreased at the same condition. In contrast, deinking efficiency of anionic type was reduced in terms of brightness, residual ink contents, and tensile strength. As flotation time was increased, yield decreased and brightness increased slightly. On the other hand, the addition of surfactant during repulping process showed better result than that during flotation process.

• Journal of Forest and Environmental Science
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• v.23 no.2
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• pp.73-78
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• 2007

Ultrasonic deinkings of white ledger were carried out to confirm whether the ink removal efficiency and pulp qualities can be improved by the ultrasonic deinking. The effects of conventional pulping and ultrasonic treatment of white ledger on the ink particle size distribution and ink removal coefficient were compared. The physical properties of paper, energy consumption and effluent qualities were measured. The ultrasonic treatment of white ledger resulted in the ink particle size distribution suitable for flotation. The ink removal efficiency, brightness, breaking length and effluent quality were improved by the ultrasonic deinking. It is expected that the competitiveness of ultrasonic deinking system can be improved by the optimization of treatment condition.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.36 no.2
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• pp.33-38
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• 2004

Toner particles used in laser and xerographic printing process is fused on paper surface so strongly that they tend not to detach easily from the recylced paper surface during pulping. Furthermore, the removal efficiency of detached toner particles by conventional screening and flotation process has limitation due to the platy shape and large size of detached toner particles. It has been shown that the removal efficiency of toners in the screening process can be increased by agglomerating the toner particles with fatty alcohol. It is not possible, however, to remove small and platy toner particles by screening process. These small and platy toner particles should be removed by flotation process. In this study the effect of fatty alcohol that used for toner agglomeration on flotation efficiency has been examined. It was shown that flotation efficiency decreased when fatty alcohol was used most probably due to its effect of reducing hydrophobicity of toner particles.