• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.46 no.4
• /
• pp.1-10
• /
• 2014

In papermaking industry, inorganic fillers are widely used for the purpose of improving opacity, brightness, printability, uniformity and dimensional stability. They are also useful for production costs and energy savings. In the past, inorganic fillers in papermaking industry only focused on micro-scale but recently, new trials on nano-powdered technology are applying. Even nano-powdered fillers are rapidly utilized for improving the optical and surface properties in coating and surface sizing, there still have some problems in wet-end process due to poor dispersibility and retention. In this study, nano-particled calcium carbonate was produced by milling the PCC and its applicability between micro sized and nano sized calcium carbonated was compared in wet-end process, and finally the sheet properties were evaluated. Nano-PCC was not retained in sheet structure without applying retention system, but with retention system nano-powdered PCC was absorbed on fiber surface with expanding the fiber networks. The application of PAM-bentonite system has resulted in high ash retention and bulky structure for copier paper, and good optical properties in brightness and opacity. However, it required to solve the weakness of low tensile property due to interruption of hydrogen bonding by nano fillers.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.31 no.1
• /
• pp.31-38
• /
• 1999

Adsorption of polymeric flocculants and dry strength agents onto the surface of papermaking fibers is critical for their effective utilization since the polymeric substances not adsorbed on fibers or fines keep recirculating in the papermaking system to cause various operational difficulties and loss of raw materials. Problems associated with the unadsorbed polymeric substances generate great attention because unprecedent interests in utilization of recycled papers and papermaking system closure. In this study, to understand the effects of recycling on the adsorption propensity of cationic polyacryamide (PAM) dry strength resin onto hardwood bleached kraft pulp fibers and fines a systematic approach was followed. Never dried bleached hardwood kraft pulp was recycled in two different ways. In mode one recycling experiment never dried pulp was beaten then recycled three times by employing simple drying and disintegrating steps. In mode two recycling experiment beating of the recycled pulp was carried out after each recycling step. Adsorption of cationic PAM on fibers and fines was evaluated employing Kjeldahl nitrogen analysis method. The influence of recycling on water retention value, carboxyl content, sheet density and tensile strength of the pulp was examined. As the number of recycling increased, water retention value of the fiber was reduced due to hornification and this in turn caused a decrease in adsorption of cationic PAM. On the other hand, the carboxyl content of the recycled fibers increased because of the oxidation of fibers occurred during drying, and this caused an increase in adsorption of cationic PAM. Because of these two opposing factors the adsorption of the cationic PAM on the recycled fibers decreased and then increased slightly at third recycling step. Increase of PAM adsorption, however, did not provide did not provide and strength improvement for the recycled pulp fibers indicating greater influence of the honification on interfiber bonding.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
• /
• 2006.06a
• /
• pp.147-152
• /
• 2006

Restoration of historical documents and arts has become important to inherit cultural properties. Most of historical documents were recorded on paper. Therefore, restoration of ancient papers is demanded and techniques for this purpose must be developed and sophisticated. In our study, several nondestructive methods for analyzing ancient paper have been developed. Image analysis using fast Fourier transform with suitable modifications was applied to optical micrographs of traditionally-handmade Korean and Japanese papers. This analysis determines the angle and anisotropy of fiber orientation of paper surfaces. Fiber orientation of traditionally-handmade Korean and Japanese papers was found to show their own characteristics in accordance with the motion of a papermaking screen made of bamboo splints. Consequently, the information on fiber orientation was found to be possible to distinguish the flow-sheet forming typical of Japanese paper and still-sheet forming typical of Korean paper. Moreover, the anisotropy was always higher for the screen side than for the top side, thus meaning that surface fiber orientation is possible to distinguish the two sides of paper of which papermaking history is unknown. An application of this technique to actual historical documents evidenced that wrapping papers were used as envelops with a lateral side up, namely, after rotating 90 degrees. A variety of cultural habits in writing letters was revealed by discrimination of the two sides.

• Korean Chemical Engineering Research
• /
• v.59 no.2
• /
• pp.174-179
• /
• 2021

Recently, hybrid coal research is underway to upgrade low-grade coal. The hybrid coal is made by mixing low-grade coal with bioliquids such as molasses, sugar cane, and lignin. In the case of lignin used here, a large amount of lignin is included in the wastewater of the papermaking process, and thus, research on hybrid coal production using the same is attracting attention. However, since a large amount of metal ions are contained in the lignin wastewater from the papermaking process, substances that corrode the generator are generated during combustion, and the amount of fly ash is increased. To solve this problem, it is essential to remove metal ions in the lignin wastewater. In this study, metal ions were removed by ion exchange with a alumina hollow fiber membrane coated with K-Phillipsite (K-PHI) zeolite. The alumina hollow fiber membrane used as the support was prepared by the nonsolvent induced phase separation (NIPS) method, and K-PHI seeds were prepared by hydrothermal synthesis. The prepared K-PHI seed was seeded on the surface of the support and coated by secondary growth hydrothermal synthesis. The characteristic of prepared coating membrane was analyzed by Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD), Energy Dispersive Spectroscopy (EDX), and the concentration of metal ions before and after ion exchange was measured by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). The extraction amount of K+ is 86 mg/kg, and the extraction amount of Na+ is 54.9 mg/kg. Therefore, K-PHI zeolite membrane has the potential to remove potassium and sodium ions from the solution and can be used in acidic lignin wastewater.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.30 no.2
• /
• pp.74-84
• /
• 1998

This study was carried out to investigate the papermaking characteristics of paper mulberry(Broussonetia kazinoki) for new Korean traditional paper(Hanji). Hanji has been traditionally made only with the bast fiber of paper mulberry. Besides mulberry bast part, wood core was utilized separately or in mixed forms as raw materials for the new Hanji. 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. In the physical properties of the Hanjis mixed with bast part and wood core pulps, the handsheet strengths were decreased as the increase of the wood core pulp contents. But the sheet strengths of Hanjis containing 10∼30% of wood core pulps were higher than those of the Hanji containing bast part pulp only. The sheet formations were improved as the increase of wood core pulp contents, while the sheet strengths were decreased.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.31 no.3
• /
• pp.1-9
• /
• 1999

Effect of furnish on enzyme activity was investigated by using the three components (cellulose, enzyme, and cationic polyelectrolyte) model papermaking system. Avicel was used as a cellulose model compound to observe the effect of adsorption and desorption of enzyme with other component and the resultant change of particle size. As an experimental result, the enzyme loses considerably its apparent activity due to the adsorption onto cellulose and cationic polyelectrolyte. Activities of enzyme applied to the actual papermaking stocks having controlled fiber length showed different behavior in terms of pulp species UKP and KOCC stocks. That is, the enzyme activity in UKP was increased as fines content increased, however, vice versa in KOCC stock . This result can be considered to be the existence of various contaminants included in the fines of KOCC . The effect of possible contaminants such as inorganic materials, calcium ion, surfactant, and conductivity on enzyme activity were also investigated.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.40 no.3
• /
• pp.1-8
• /
• 2008

The efficiency of retention systems including compozil-G, hydrocol, compozil-S, and micropolymer under highly closed papermaking system was evaluated using contaminated white waters prepared in the laboratory. Compozil-G and compozil-S performed better in retention than hydrocol and micropolymer systems. This suggested that stronger hydrogen bonding between fiber and guar gum or starch was formed to give stronger flocculation and better retention. Especially compozil-G outperformed compozil-S in retention, and this indicated the presence of stronger interaction between guar and cellulose fibers probably due to their similarity in chemical structure. Two compozil retention systems decreased the cationic demand and COD more effectively than hydrocol and microparticle systems. In particular, compozil-G that uses guar gum was highly effective in decreasing anionic trashes at low dosage.

• Journal of the Korean Graphic Arts Communication Society
• /
• v.18 no.1
• /
• pp.121-139
• /
• 2000

This study is to test the possibility of applying the low-molecular weighted waste cellulase, which is produced in the process of cellulase production, to paper making. After experimenting on high-crystallized non-wood fibers with beating catalyst. I got the result that the condition for the optimal effect is temperature 40~6$0^{\circ}C$, the time 90min to 120min, pH 5.0 to 6.0, the enzyme contents 0.3% and that the effect of beating such as slight reduction of fiver viscosity, increase of water retention value(WRV) and shortening of fiber length was increased with waste cellulase. Through this process, the density, folding endurance, tensile strength and burst strength of paper was remarkably increased, which is inferred to result from the increased flexibility of fiber by individual characteristics of non-wood fiber, which was high-crystallized by penetrated low-molecular weight cellulases in the fiber.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.47 no.6
• /
• pp.41-48
• /
• 2015

Fiber identification was attempted for the early twenty century documents that were classified as national archives in Korea, as an initial step for establishing scientific preservation and restoration method. Fiber staining with C stain and a digital microscope were used for the observation. All the documents observed consisted of mostly softwood fibers from fir (Abies) and other minor supplementary fibers, and they were all deteriorated seriously by various damages and aging process. It seemed that at around 1914-1934, fir was used frequently as papermaking raw material.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.43 no.5
• /
• pp.27-33
• /
• 2011

Hemp bast pulp cooked at temperature below $100^{\circ}C$ followed by defibration by the knife and the valley beater, respectively was mixed with softwood pulp varying the amount of hemp pulp in order to find the optimum condition for making hemp-wood paper. Both the knife and the valley beaters contributed to the dispersion of pulp fiber well. Lots of shives were found when the knife beater was applied exclusively, but the fibers were dispersed well when freeness dropped to 600 mL CSF and 500 mL CSF by the valley beater. Air resistance decreased drastically below 500 mL CSF where rapid disrupture of pulp fiber occurred. As the values for freeness and hemp fiber content increased, so did roughness and bulk. It was apparent that the tear strength of hemp-wood paper was on the rise drastically as hemp fiber content increased. Nevertheless the optimum hemp fiber content of hemp-wood paper would be 20% considering the decrease in both tensile and burst strengths as well as sheet formation.