• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.2
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• pp.85-95
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• 1998

Traditionally, Hanji had been made only with the bast fiber of paper mulberry (Broussonetia kazinoki). Nowadays, Hanji has been made mainly in the mixed forms of paper mulberry bast fiber and waste paper, and consequently it has raised many problems using them. This study was carried out to investigate the characteristics of Hanji mixed with paper mulberry bast part and whole stalk pulps. Hanjis made from the solfomethylated pulp were shown higher brightness and sheet strengths than those from alkali and alkali-hydrogen peroxide pulps. The brightness of solfomethylated pulp was found to be high enough not to need additional bleaching. The sheet formations were improved as the increase of whole stalk pulp contents, while the sheet strengths were decreased. In the physical properties of the Hanji mixed with bast part and whole stalk pulps, the handsheet strengths were decreased as the increase of the whole stalk pulp contents. The tensile strength and folding endurance of the Hanji containing 40∼60% of whole stalk pulps were higher as compared to the others.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.11a
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• pp.9-14
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• 2006

Deinking is a series of unit operations designed to detach ink from cellulose fibers and separate the dispersed ink from the pulp slurry. Deinking chemicals are process aids that enable expensive mill equipment used in these unit operations to operate more efficiently. This paper presents an overview of ONP deinking efficiency with cellulolytic enzymes and synthetic collector in low alkalinity process. The deinking efficiency of old news print even in low alkalinity condition was enhanced with enzyme contained complex agent. The brightness of deinked pulp was increased with less residual ink particles and yield of deinked pulp was improved compared to the deinked pulp of conventional alkaline method.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.11b
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• pp.149-152
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• 1999

A new process for deinking of colored offset newsprint, i.e. enzyme treatment in cooperation with ultrasonic wave was developed in the present study. The physical characteristics such as fiber length, coarseness, crystallinity index of the deinked pulps were investigated and the sugar residues released from the treatment were analyzed. It was found that colored offset newsprint could be deinked effectively by cellulase treatment when ultrasonic wave was applied. The brightness increased by 5% ISO over that of control experiment and the pigment content was reduced markedly. Though the ultrasonic wave had little effect on the strength and crystallinity of the pulp, the treatment of enzyme combined with ultrasonic wave reduced the coarseness and fiber length to some extent. It was also found that ultrasonic wave could accelerate the hydrolysis of cellulose and hemicellulose during the cellulase treatment.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.30 no.1
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• pp.53-62
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• 2024

Molded pulp products has become more attractive than traditional materials such as expanded polystyrene foam (EPS) owing to low-priced recycled paper, environmental benefits such as biodegradability, and low production cost. In this study, various design factors regarding compression and cushioning characteristics of the molded pulp cushion with truncated pyramid-shaped structural units were analyzed using a test specimen with multiple structural units. The adopted structural factors were the geometric shape, wall thickness, and depth of the structural unit. The relative humidity was set at two levels. We derived the cushion curve model of the target molded pulp cushion using the stress-energy methodology. The coefficient of determination was approximately 0.8, which was lower than that for EPS (0.98). The cushioning performance of the molded pulp cushion was affected more by the structural factors of the structural unit than by the material characteristics. Repeated impacts, higher static stress, and drop height decreased the cushioning performance. Its compression behavior was investigated in four stages: elastic, first buckling, sub-buckling, and densification. It had greater rigidity during initial deformation stages; then, during plastic deformation, the rigidity was greatly reduced. The compression behavior was influenced by structural factors such as the geometric shape and depth of the structural unit and environmental conditions, rather than material properties. The biggest difference in the compression and cushioning characteristics of molded pulp cushion compared to EPS is that it is greatly affected by structural factors, and in addition, strength and resilience are expected to decrease due to humidity and repetitive loads, so future research is needed.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.5
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• pp.68-73
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• 2015

Electron beam irradiation is also an eco-friendly treatment compared to other physical and chemical treatments. In this study, we attempted to evaluate the possibilities of energy savings by applying electron beam irradiation to the refining process. After softwood unbleached kraft pulp (UKP) was irradiated with electron beams at 50 and 100 kGy, it was beaten in a laboratory beater, and then its freeness and fiber properties were analyzed. The physical properties of their fiber handsheet were also and measured. As the irradiation dose of the electron beam and the beating time increased, lower freeness and fiber lengths of the UKP were observed. Handsheets made from UKP that was irradiated by electron beam and beaten showed a reciprocal relationship with the irradiation dose of the electron beam, in particular, the strength of the handsheets decreased dramatically at 100 kGy of irradiation. Therefore, it was confirmed that electron beam irradiation is effective in reducing the beating time or beating energy. But the irradiation dose must be controlled under 50 kGy to minimize the loss of paper strength.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.42 no.3
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• pp.50-57
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• 2010

A mill trial was performed in a kraft paper mill in order to evaluate the possibility of utilizing dual polymer dry strength aids system consisting of cationic PVAm and anionic PAM. It was found that the cationic PVAm - anionic PAM dry strength additives can improve paper strength without significantly disturbing the stability of the kraft papermaking process when virgin UKP was used as a furnish. Tensile strength (25.3% in machine direction, 48.4% in cross machine direction), elongation of paper (31.6%, 15.6%) and tensile energy absorption (48%, 54%) were improved. Air permeability of the kraft paper was improved as well (22%). Tear strength was decreased with PVAm dry strength aids system, but it can be compensated with decreasing refining degree. In addition, the mill trial results indicate that highly air permeable kraft sack paper can be produced by the addition of PVAm dry strength agents at the stock with reduced freeness.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.30 no.4
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• pp.35-41
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• 1998

The bacterial cellulose has many unique properties that are potentially and commercially beneficial. In order to make opaque product from this cellulose, filling properties by fillers should be known. This study was performed to investigate the effect of filler addition on physical properties of sheets from bacterial cellulose. The effect of filling on its optical properties was also discussed. The apparent density and internal bonding strength of bacterial cellulose sheet are decreasing with the increase of filler contents. Those adversely affect Young's modulus and physical property of the sheet, but these negative phenomena of the bacterial cellulose sheet by filler addition are not so sensitive compared to substantial decreasing of physical properties of ordinary hardwood KP. This strength decrease would be attributed to the decrease of relative bonding sites among pulp fibers. Concerned to optical properties, the bacterial cellulose sheet shows high increase of brightness and opacity according to filler loading, but no significant changes in porosity up to 17.3% loading because of fine and filamentous structure of bacterial cellulose fibers.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.3
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• pp.90-95
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• 1999

The durability of handmade paper prepared by potassium carbonate cooking of paper multiberry (Broussonetia Kazinoki Sieb).was investigated. The potassium carbonate paper before and after heat aging had better strength properties, breaking length and folding endurance than those of the soda paper, except of lower brightness .After 30 days of heat aging , these strength properties were still maintained . however, there was almost no difference in the infrared spectra and the crystallinities calculated by X-ray diffraction curves between the potassium carbonate paper and the soda a paper. The durability of the potassium carbonate paper was though to be due to decrease in the pulp damage caused by weak alkaline cooking condition. The results indicated that the paper prepared by the potassium carbonate cooling method could have better permanence than that prepared by the conventional soda cooking method.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.45 no.6
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• pp.88-95
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• 2013

Effects of beating and water immersion time on fiber swelling and paper properties were elucidated for the fundamental study of producing high bulk paper. Chemical pulps were beaten for various freeness and the beaten pulp was immersed in water up to 24 hours. Fiber swelling was evaluated by measuring water retention value (WRV). It was found that fiber swelling, bulk and paper strength were quickly changed at the initial stage of beating. Immersion in water did not significantly increase WRV, paper density and strength, implying that soaking in water alone could not effectively swell fiber wall. In order to swell further, hydrogen bonds between fibrils in fiber wall and hence fiber wall structure shall be broken by mechanical force during beating.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04b
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• pp.386-389
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• 1999

Amphoteric polymers have brought to papermakers' attention gradually. In this paper, a series of amphoteric starches with different cationic and anionic degree of substitution (DS) are prepared. Better product has been selected and used under different condition. As retention and drainage aids, amphoteric starches were used in shorter fiber length, weak strength and poor drainage bleached AQ-Soda wheat straw pulp. In neutral and alkaline papermaking system, when amphoteric starches contain 0.024-0.026 anionic degree of substitution (DS), it is shown that the higher the cationic degree of substitution (DS) in amphoteric starches, the better the filler retention. The filler retention is improved 12.5%, 30.3%, and 35.1% and 32.5% respectively by adding 1% amphoteric starch LS-L2 -1 (0.034), LS-L2-2 (0.040), LS-L2-3 (0.047) and LS-L2-4 (0.052). But the strength of handsheets if affected a little. By adding 2% Al2 (SO4)3 and 1.5% LS-L2-3 at pH 7.5, filler retention can be improved from 38% to 80%, and breaking length of sheet only decreases 3.2%. As dry strengthening aids, amphoteric starches were used in eucalyptus APMP. Amphoteric starches are used in eucalyptus APMP. The amphoteric starch LS-L2-2 is better dry strength aid. Adding 1% LS-L2-2 can improve breaking length 24.5%, burst index 42.9%, tear index 38.8%, folding endurance and density of the handsheets.