• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.38 no.2 s.115
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• pp.52-60
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• 2006

Environment-friendly shock-absorbing materials were made of wastepaper such as Korean old corrugated containers(KOCC) and Korean old newsprint (KONP) with a vacuum forming method. The plate-like cushioning materials made of KOCC and KONP respectively by vacuum forming showed superior shock-absorbing properties with lower elastic moduli compared to expanded polystyrene (EPS) and pulp mold. Even though the plate-like materials had many free voids in their fiber structure, their apparent densities (${\approx}0.1g/cm^3$) were a little higher than that of EPS (${\approx}0.03g/cm^3$) and much lower than that of pulp mold(${\approx}0.3g/cm^3$). However, the elastic moduli of the cushioning materials made of wastepaper were much lower than that of EPS or pulp mold. This finding implies that the cushioning materials made of KOCC fibers containing more lignin than KONP show better shock-absorbing properties than KONP. Moreover, the cushioning materials made of KOCC and KONP respectively showed greater porosity than pulp mold. The addition of cationic starch to the cushioning materials contributed to the increase in the elastic modulus to the same level as that of EPS. Furthermore, the deterioration in fiber quality by repeated use of wastepaper played a positive role in improving shock-absorbing ability.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.41 no.4
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• pp.82-90
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• 2009

It is very important to utilize effectively fibrous waste paper in terms of cost savings, environmental effects, and governmental policies. The quality of final products and runnability of papermaking process are primarily affected by constitutions of fibrous raw materials. In specific, board grade paper depends directly on compositions of waste paper bales. At present, the raw materials of board grade paper are mainly derived from lots kinds of wastepaper. Some papermaking countries, like EU, USA and Japan have advanced classification and management systems of recycled fiber, but Korea has not yet organized systematically. In this study, evaluation of wastepaper bale compositions and their fiber properties were carried out for effective utilization of fibrous raw materials for board grade paper production. 3 kinds of wastepaper bales were classified to fibrous or non-fibrous materials. In case of fibrous materials, KOCC, kraft sack paper and white duplex board matters were main component in total weight basis, and in case of non-fibrous materials, vinyl, plastic and cloth matters were main component, in turns. 3 representative kinds of waste paper were disintegrated and classified, and then prepared to handsheet for evaluation of recycled fiber property. Consequently, fines and ash content of waste paper, isolated from KOCC and white duplex board were higher than that of kraft sack paper. pH values of all kinds of waste fibers were neutral or weak alkaline.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.471-474
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• 2006

Environment-friendly shock-absorbing materials were made of wastepaper such as old corrugated containers (OCC) and old newspapers (ONP) with a vacuum forming method. The plate-like cushioning materials made of OCC and ONP respectively by vacuum forming showed superior shock-absorbing properties with lower elastic moduli compared to expanded polystyrene (EPS) and pulp mold. Even though the plate-like materials had many free voids in their fiber structure, their apparent densities (${\approx}0.1g/cm^{3}$) were a little higher than that of EPS (${\approx}0.03g/cm^{3}$) and much lower than that of pulp mold (${\approx}0.3g/cm^{3}$). However, the elastic moduli of the cushioning materials made of wastepaper were much lower than that of EPS or pulp mold. This finding implies that the cushioning materials made of OCC fibers containing more lignin than ONP show better shock-absorbing properties than ONP Moreover, the cushioning materials made of OCC and ONP respectively showed greater porosity than pulp mold. The addition of cationic starch to the cushioning materials contributed to an increase in the elastic modulus to the same level as that of EPS. Furthermore, the deterioration in fiber quality by repeated use of wastepaper played a great role in improving shock-absorbing ability.

• KSBB Journal
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• v.29 no.3
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• pp.193-198
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• 2014

Pretreatment of wastepaper using aqueous glycerol under high pressure was studied to enhance the enzymatic hydrolysis. The pretreatment was conducted over a wide range of conditions including temperatures of $150{\sim}170^{\circ}C$, sulfuric acid concentrations of 0.5~1.5%, and reaction times of 30~90 minutes. After the effect of glycerol concentration on the pretreatment performance was investigated, 70% glycerol was selected. As glycerol concentration was increased, higher digestibility was achieved due to higher lignin removal. The optimum condition was found to be around $160^{\circ}C$, 1%, and 60 minutes. At this condition, 60% and 35% of hemicellulose and lignin, respectively, were removed, while only 5% of cellulose was lost. The enzymatic digestibility was 76%, meaning that 73% of the glucan present in the initial substrate was recovered as glucose after enzymatic hydrolysis. Also, it was found that the temperature and acid concentration than the reaction time were more strongly related to the compositional removals and enzymatic digestibility.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.123-128
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• 2006

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 deinking 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.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.

• KSBB Journal
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• v.28 no.1
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• pp.48-53
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• 2013

Pretreatment of wastepaper using aqueous glycerol was investigated to enhance the enzymatic hydrolysis. The effects of four factors (solid/liquid ratio, glycerol concentration, acid concentration, and reaction time) on the dissolution yield, the removal of cellulose, hemicellulose and lignin, and the enzymatic digestibility were examined at $150^{\circ}C$. The 1/8 of solid/liquid was determined to perform the reaction uniformly, and the 93% of glycerol concentration was found to be a minimum concentration to conduct the reaction under atmospheric pressure. Also, it was found that the acid concentration and reaction time were strongly related to the dissolution yield and the removal of cellulose, hemicellulose and lignin, but moderately to the enzymatic digestibility. At an optimum condition of $150^{\circ}C$, 1 h and 1% acid concentration, 56% and 49% of hemicellulose and lignin, respectively, were removed, while only 4% of cellulose was removed. The enzymatic digestibility at this condition was 86%, meaning that 83% of the glucan present in the initial substrate was converted to glucose. Compared to glycerol with ethylene glycol as a pretreatment solvent, glycerol is much cheaper than ethylene glycol, but ethylene glycol is superior to glycerol in delignification.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.1
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• pp.45-52
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• 2001

Recycling of wastepaper is very important for the environmental protection. However inferior strength and slower drainage characteristic that are brought by the hornification and the increase of fines respectively limited the increase of wastepaper recycling. The purpose of this study is to obtain some fundamental information that is helpful to develop the technologies which can improve the characteristics of recycled fibers. Softwood bleached kraft pulp was curlated with Hobart mixer at several different consistency. The curlation of fibers can cause the internal fibrillation and decreasing the crystallinity without serious damage of fiber surface. Curl index, kink index, freeness and WRV were increased, but crystallinity was decreased with the increase of curlation consistency.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.33 no.3
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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.

• 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.