• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.6
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• pp.164-169
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• 2015

Nowadays blending ratio of OMG (old magazine) in recovered paper used for manufacturing newspaper have been increased. When large amount of OMG is consumed in newsprint mill, brightness can be improved by inorganic pigments of coating layer. On the other hand decrease in yield of deinking process will be encountered because the pigments can be removed as reject of froth flotation process. Therefore selection of the optimal deinking agent is an important. Non-ionic surfactant have been used widely in newsprint mill. Non-ionic surfactant has amphoteric characteristics. Hydrophilic group is ethylene and propylene oxide that can induce hydrogen bonding with water molecules. In this regard, cloud point is an important parameter in order to control efficiency of deinking process because hydration of the hydrophobic group can be varied according to temperature of a system. In this study, deinking properties of ONP at high blending ratio of OMG was analyzed according to cloud points of non-ionic surfactants. $L^*$, $a^*$, $b^*$, brightness and effective residual ink concentration did not affected by the change of cloud points. Especially, flotation reject decreased significantly according to increase in cloud point of the non-ionic surfactant. Consequently, when a nonionic surfactant having a cloud point higher than the temperature of the system is used, properties of the deinked pulp can be maintained and yield of deinking process can be improved.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.2
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• pp.58-67
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• 2001

MOW (Mixed Office Waste) mainly consisted of photocopied paper is being recycled to produce tissue or fine paper products. Toner particles that are fused and set on paper surface in photocopying process turns into large and plate-shaped particles after repulping which prevents them to be removed effectively in flotation deinking. The immediate purpose of this study is to find the effective deinking technology that increases the recycling potential of photocopied papers for manufacturing tissue and fine paper products. In this study the effects of pulping temperature and the type of hydrophobic groups of nonionic surfactants on the deinking efficiency of photocopied paper has been investigated. Particle size distribution of the toner particles after pulping and flotation, brightness, yield and ash removal were investigated. The size of toner particles after pulping increased as the pulping temperature was increased. When pulping at the low temperature finer toner particles were generated, however, greater amount of toner particles was found to attach to the fiber. When the pulping temperature was greater than Tg of the toner, the amount of coarse hairy particles increased. When nonionic surfactants with a double bond in hydrophobic groups were used, toner removal efficiency, brightness and ash removal were increased. As the addition level of surfactant was increased, yield decreased rather sharply without improving brightness.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.39 no.5
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• pp.12-19
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• 2007

Enzymatic deinking method can avoids the alkaline environment as usual required in chemical deinking, which consequently cuts chemical costs and reduced the white water pollution. The electrostatic wastepaper was dinked with commercial cellulolytic enzymes and surfactant in neutral pH and the effectiveness of deinking and the physical properties of deinked pulp were evaluated. The disintegrating efficiency of the electrostatic wastepaper in neutral pH was enhanced with enzyme treatments. Although the freeness of deinked pulp with enzymes was higher than that of deinked pulp with chemical de inking agents, the brightness of the enzymatic deinked pulp was slightly lower than that of the chemical deinked pulp. But, by additions of nonionic surfactants, the brightness of deinked pulp was increased with less residual ink particles and mechanical properties of enzymatic deinked pulp was improved compared to the deinked pulp of conventional alkaline method.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.5
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• pp.12-17
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• 1999

This study was to evaluate applications of the alkalophilic enzymes from Coprinus cinereus 2249 with old newsprint(ONP). A enzymatic deinking process based on alkalopholic enzymes was investigated . It was found that alkalophilic enzymes could effectively deink old newsprint. When applied on deinking of the old newsprint, 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.

• Journal of the Korean Graphic Arts Communication Society
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• v.18 no.1
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• pp.95-102
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• 2000

This paper presents the second part of a study of deinking using wort. Physical properties of deinked pulps such as tensile strength, bursting strength and tearing resistance were investigated. In order to analyze the properties, the fiber length and coarseness of deinked pulp was also measured. Results of deinking experiments showed that the deinking efficiency of enzyme treatments was higher than that of chemical treatments in strength properties such as tensile strength, bursting strength and tearing resistance on the the whole. we think that the reason why is that the fiber length and coarseness of deinked pulp with wort are more increased and decreased than those of deinked pulp with chemicals individually.

• KSBB Journal
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• v.13 no.5
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• pp.593-598
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• 1998

Biological deinking process of used papers was studied by the polymer modified cellulase. Cellulase was modified with copolymers which consist of polyoxyethylene derivative and maleic anhydride(MA). The MA functional groups of copolymer can react with amino acids groups of the cellulase without much loss of activity. Modified degree of amino acids was controlled by the added copolymer. The maximum modified degree was about 60% and it was obtained when the weight ratio of copolymer and cellulase was 4. The remained activity of the maximum modified cellulase(MMC) was higher than 80% of native cellulase. The MMC's concentration was 0.05-2.0 wt% relative to the dry paper. In mechanical pulping process, cellulase enhanced the detachment of the ink particle from the used paper by partial hydrolysis of the fiber. The polyoxyethylene of modified cellulase produced the forms which can float the separated ink particle. Compared to the convention deinking method with NaOH or organic chemicals, the new biological deinnking process improved the physical properties such as freeness, tearing strength and whiteness.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.35 no.1
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• pp.34-40
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• 2003

This study was carried out to select the useful bacteria which secret extracellula enzymes for enzymatic deinking agent of old newspaper. CMCase, FPase and xylanase activities of the bacteria liquid culture were measured at optimal growth conditions. Clear zone test was checked on the solid culture. The results of this study were as follow: Eight strains of 28 bacteria isolated from a paper mill soil ground were shown strong CMCase and xylanase activity with the clear zone test. The optimal pH and temperature for culture growth were 6~8 and 26~$34^{\circ}C$, respectively and optimal culture period were less than 60 hours. Based on CMCase, FPase and xylanase activity, strain No. 18, 21, 22 and 28 which were relatively higher than the other strains, were selected for further enzymatic deinking research.

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

• 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.

• Applied Chemistry for Engineering
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• v.10 no.5
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• pp.726-730
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• 1999

To investigate the deinkability according to the ink composition, deinking chemicals and aging time, newspaper was printed with different solvent types: 30% soy-based oil ink(A), 50% soy-based oil ink(B), 45% mineral oil ink(C) and 42% linseed oil ink(D). The newspapers were aged naturally for 15, 30, 90, 180 days, and were deinked with various deinking chemicals. The brightness of the deinked pulp of newspaper was affected by the ink composition, aging time and deinking chemicals, i.e., it was decreased with increasing aging time in the order of C, A, B and D. And the brightness also decreased in the order of lipase, cellulase and conventional chemical. The deinking yield showed the same tendency as the brightness variation at a given brightness. The strength of the deinked pulps increased until 30 days, but decreased or maintained after that time. And the strength decreased in the order of C, D, B and A, and also decreased in the order of lipase, conventional chemicals and cellulase.