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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Korea Technical Association of The Pulp and Paper Industry
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Journal DOI :
Korea Technical Association of the Pulp and Paper Industry
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Volume & Issues
Volume 30, Issue 4 - Dec 1998
Volume 30, Issue 3 - Sep 1998
Volume 30, Issue 2 - Jun 1998
Volume 30, Issue 1 - Mar 1998
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Pulp Bleaching Effect and Ionization Rate of Chlorine Dioxide by Additives and Various pH Conditions(I)-Ionization of ClO
and Formation of Chlorate in Pulp Bleaching-
;Li Jun Wang;;
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 30, issue 3, 1998, Pages 1~6
Elementally Chlorine Free (ECF) bleaching will be superior than Totally Chlorine free (TCF) bleaching, not only because they have no significant difference in effluent toxicity, but also those pulps bleached by ECF have higher brightness, strength, yield, etc., over those by TCF. With this belief, this paper focused on the chemistry of chlorine dioxide decomposition and ionization, both in water solution and in pulp slurry. Special attention was paid to chlorate ion because there have been controversies as how it is formed and what its behavior to the end pH of pulp bleaching is. As a result, during ionization of chlorine dioxide with water, both chlorate and chlorite were found to increase with increasing pH, but during ionization with pulp, chlorite was found to increase with end pH while chlorate decreased with increasing end pH. In the case of ionization with water, the disproportion equation
was thought to become the main reaction with the increasing pH, while in the case of ionization with pulp, the reaction
was the main reaction contributing to the formation of chlorate. Based on this above opinion, the contrary results of chlorine dioxide ionization from different researchers were discussed and explained.
Effects of Xylanase Treatment on Recycled Pulp Properties
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 30, issue 3, 1998, Pages 7~14
It is well known that the recycling of pulp generates a lot of fines, and cause the hornification of fiber. Both phenomena have been contributed to a limited use of recycled fiber. Among several means which can improve the properties of recycled fiber, enzymatic treatments are considered as an effective means. Thus the effects of xylanase on the properties of recycled pulp were investigated in this study Xylanase treatment showed some refining effect at a small dosage while the fines and fibrils were reduced at higher dosage as shown in the treatment with cellulase-hemicellulase. The interesting finding is that the WRV of recycled fiber treated with xylanase was higher than that treated with the mixture of cellulase and hemicellulase. Breaking length and tear index of recycled fiber treated with xylanase were also higher.
Studies on the Recycling Technology of the Waste Paper with Wood Degradable Enzyme(II)-Effect of Crude Enzyme on the Bleaching Characteristics and Physical Properties of Waste Paper-
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 30, issue 3, 1998, Pages 15~21
Crude enzymes of Trichoderma viride and Phanerochaete chrysosporium were evaluated for their effect to brightness and physical properties of recycled pulp from newspaper and corrugated container board. The brightness of recycled pulp from newspaper increased with crude enzymes from Trichoderma viride and Phanerochaete chrysosporium. The brightness of recycled pulp of corrugated container board increased with crude enzyme from Phanerochaete chrysosporium, but decreased with crude enzyme from Trichoderma viride. The Δbrightness with chemical bleaching of crude enzyme treated pulp was lower than that of heat killed enzyme treated pulp, but the final brightness of pulp was increased. Modification of recycled paper with crude enzymes can result in a substantial increase in physical properties with little no loss in pulp freeness.
Recycling of Wastepapers (I) : -Improvement of Drainage and Strength Properties of Testliner Through the Blended Enzyme Treatment-
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 30, issue 3, 1998, Pages 22~28
The blended enzymes were applied for OCC recycling system to use the selective activities of various enzymes. Cellulase and hemicellulase were very effective in terms of the strength of recycled paper The effect of the addition of amylase on the drainage improvement indicates that the starch, which was used as an adhesive of corrugated container, deteriorates the drainage property in OCC recycling system. From the result of Scheffe's analysis, the combination of cellulase and amylase (50/50, w/w) were the most effective in improving the drainage properties with increased strength.
A Quantitative Analysis Method for Studing AKD Hydrolysis
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 30, issue 3, 1998, Pages 29~37
In order to set up a proper AKD quantification method for studing AKD hydrolysis, a quantitative analysis method using Uv/vis spectroscopy was evaluated and compared to the conventional GC-MS analysis. Hydrolysis rates of AKD emulsions during storage at 4
were measured by the UV/vis analysis. Owing to its simplicity and capability of measuring the unreacted AKD significantly even in a small amount, UV/vis method proved to be more suitable for studing AKD hydrolysis than GC-MS analysis. AKD hydrolysis was affected by the types of emulsifiers. Polymer stabilized AKD emulsion hydrolyzed more rapidly than starch stabilized AKD.
Development of Multi-functional Mulch Papers and Evaluation of Their Performance-Studies for Reducing the Basis Weight of Mulch Paper-
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 30, issue 3, 1998, Pages 38~45
Soil and water contamination caused by the abundant use of agricultural chemicals including herbicides and fertilizers draws public concerns since these chemicals may pollute the agricultural lands as well as the food products grown on these lands. As a method to reduce the use of agricultural chemicals mulching with thin plastic film has been commonly practised for many years. Although use of the plastic film for mulching is very effective in preventing the growth of weed, it is almost impossible to remove all of the plastic film from the agricultural land and the remaining film eventually contaminates the soils. Therefore, it is very imperative to develop a mulching material that decomposes completely to prevent soil pollution problems and to enhance the competitive edge of domestic agriculture. Mulch papers are believed to have many positive characteristics in preventing problems caused by the plastic mulch film since it decomposes completely after use. However, the basis weight of mulch papers needs to be reduced to improve its handling properties and to reduce the raw material costs of pulps. In this paper the possibilities of using domestic old corrugated containers in producing mulch papers were examined. Also use of unbleached softwood kraft pulps and dry strength additives were exploited along with two-layered sheet forming technology in decreasing the basis weight of the mulch paper. Results showed that reduction of 20g/
of basis weight of mulch paper was possible by the appropriate raw material selection and application of strength resin. To use the mulch papers in paddy fields, however, further research to improve its durability should be pursued.
Molecular Diffusion of Water in Paper(II)-Water-diffusion theory on pore structure of paper-
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 30, issue 3, 1998, Pages 46~56
The objective of this study was to investigate the relationship between water vapor diffusion properties and the pore structure of paper. Gas-phase molecular diffusivity of water vapor through pores was determined based on the kinetic theory of gas. A mathematical model was derived to characterize the dimensional changes of the pore caused by the fiber-swelling mechanism. A modified-Fickean diffusion model was designed to simulate the water-vapor diffusion phenomena in porous paper web. Structural characterisocs of paper pores including the tortuosity and the shape factor was studied on a theoretical basis of Knudsen flow diffusion. Results are summarized as follows: 1. The theoretical water vapor diffusivity in gas-phase was 0.092
/min, 2. Porosity was inversely proportional to the degree of wet-swelling of paper, 3. Solid-phase water-diffusivity of fiber was 1.2
, 4. Modified diffusion model was fairly consistent to the experimental data (from part I), and 5. The Fickean pore tortuosity, ranging from 1,000 to 2,500, was in inverse proportion to the porosity of paper, and the Knudsen shape factor and length-angle factor for micro-pores in paper were 0.5~3.5 and about 340, respectively.
The Study of the Effects of Basis Weight and Formation on Tensile and Tear Strengths Using Light Transmitance Method
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 30, issue 3, 1998, Pages 57~62
This study is intended to analyze how formations affect the tensile and tear strengths of paper at the same basis weight. Light transmitance method using a scanner was employed to measure the degree of formation in terms of gray scale. Scanning method showed close relationship between gray scale value and basis weight. At the same basis weight a sheet of paper with good formation had higher tensile strength in terms of breaking length than that of a paper with poor formation. There was little difference in tear strength depending on formations.
Effect of Binder on Coating Layer Structure and Surface Strength of Coated Paper
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 30, issue 3, 1998, Pages 63~72
This research was intended to evaluate the effect of carboxymethylcellulose(CMC) on the coating structure and surface strength of coated paper prepared with amphoteric latex based coating color. Printability and optical properties of coated papers were compared. The influence of the consolidation behavior of coating color on the coating structure and the surface strength of coated paper was investigated. Compared with the conventional anionic latex, amphoteric latex formed bulkyer, smoother and more porous coating layer, which in turn, restricted binder migration in the coating layers, and facilitated immobilization of coating colors. However, dry pick strength of coated paper was decreased. The addition of CMC to these systems had strongly influenced on. the consolidation behavior and porosity in the dry state, through forming the network structure of coating layers by the interaction with amphoteric latex particles. Thus, printability and optical properties of coated papers were improved. Results indicated that amphoteric latex could be practically applied to the paper coating to improve printability and optical properties of coated papers.
Coagulation of Cationic Rosin Emulsion and its Effect on Ink Receptivity of Coating Layer
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 30, issue 3, 1998, Pages 74~83
The phenomenon of decrease in sizing efficiency when the stock temperature is increased is well recognized as summer sizing, and this is believed to be caused by uneven distribution of sizing agents on paper surface most often incurred by coagulation of sizing agents. When unevenly sized paper is used as coating base stock, nonuniform consolidation of the coating layer may result, which, in turn, causes uneven distribution of binder on coating surface. This causes nonuniform ink absorption to produce print mottle. In this study the effects of simple or polymeric electrolytes, storage temperature and time on the coagulation of cationic dispersed rosin size were investigated using a turbidity measurement method which was verified to correlate well with the particle size of rosin emulsion or its coagulates. Handsheets sized with rosin dispersions coagulated under various conditions were prepared and their sizing degree and coated paper properties including gloss and ink density were examined. The relationship between the sizing nonuniformity of coated papers and its ink absorption property was evaluated. Turbidity of rosin emulsion increased as the storage temperature and time were increased. Addition of simple or polymeric electrolytes caused reduction in
-potential of the rosin dispersion and accelerated the coagulation tendency substantially. Reversion of the
-potential of rosin dispersion, however, did not occur when coagulation was induced with simple electrolytes. On the other hand, addition of an anionic polyelectrolyte reversed the
-potential of the flocculated rosin dispersion. This indicated that electrical double layer compaction and bridging flocculation were coagulation mechanisms for simple and polymeric electrolytes, respectively. Sizing degree decreased as coagulation of rosin was increased. Paper gloss, ink gloss and ink density were increased when sizing degree of base stock was increased most probably due to prevention of base paper swelling and increased binder migration to coating surface. This suggested that uneven printing ink density occurred when uneven sizing development was induced by coagulation of rosin particles.
Elemental Chlorine Free Bleaching of Kraft Pulps with Enzymes(II) -Pinewood Kraft Pulp-
Journal of Korea Technical Association of The Pulp and Paper Industry, volume 30, issue 3, 1998, Pages 84~96
This study was carried out to bleach the Pinewood kraft pulp without the elemental chlorine using the xylanase or wastewater(We:wastewater enzymes) effluented from the submerged biofilter reactor containing the fungi, Phanerochaete sordida YK-624. So in this research, the proper treatment conditions(pH, temperature, dosage and time) were investigated respectively. And after the various kinds of multistage bleaching of pulps, the properties of pulps were tested. From the experimental results, we can conclude as follows. In the treatments of Pinewood kraft pulps with xylanase, the proper pH, temperature, enzyme dosage and time were 8.0,
, 400EXU/kg and 3 hr. respectively. And in the case of treatment with a wastewater(We) effluented from the submerged biofilter reactor, the proper pH, temperature and time were 5.0,
and 3 hr. respectively. On the other hand, Pinewood kraft pulps were bleached by the method of a multistage bleaching using xylanase or We instead of elemental chlorine. Consequently, the strengthes and brightnesses of pulps bleached by the method mentioned above were lower than those of pulp bleached by the conventional method using the elemental chlorine. But it is possible to improve the brightnesses through the increase of chlorine dioxide dosage or use of hydrogen peroxide in the final bleaching stage.