• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.317-321
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• 2006

The investigation of the formation of organic sulfur compounds (i.e., odor species), mainly methyl mercaptan and demethyl suifide, during kraft pulping has been conducted, in which both hardwood and softwood species were used. It was discovered that there is an organic sulfur compounds formation phase transition point with respect to delignification extent. The transition point occurs at a kappa number of approximately 35 and 20 for softwoods and hardwoods, respectively. The results also showed that both low sulfidity and anthraquinone (AQ) addition are helpful to control the formation of theses organic sulfur compounds during kraft pulping. Whereas Hexenuronic acid (HexA) has contribution to Kappa number, the extended delignification not only lead to low pulp yield, but also be adverse to odor control. A significant in-digester odor reduction can be achieved if the pulping is to be terminated before phase transition point and combined with AQ addition.

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

• Journal of the Korean Wood Science and Technology
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• v.18 no.2
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• pp.25-35
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• 1990

To investigate the effects of swelling treatment by ammonia on characteristics of carboxymethy1cellulose(CMC) and CMC solution, the domestic kraft pulp pretreated with 5%, 10%, 15% and 20% $NH_4OH$ solution, was carboxymethylated by the standard method, and then the CMC prepared was tested. The physical properties of CMC and CMC solution, such as degree of substitution, transparency. viscosity, weight increase and solubility, were measured, and the comparison with commercial domestic CMC used as a food additive was done. The results obtained were as follows; 1. In CMC manufactured by standard solvent method, hardwood bleached kraft pulp(LBKP) was more substituted than safwood bleached kraft pulp(NBKP), and viscosity of NBKP was higher than that of LBKP. 2. When ammonia swelling treatment was done, degree of substitution gradually decreased with increasing concentration of $NH_4OH$, and degree of substitution of LBKP decreased with a larger range than that of NBKP. 3. When ammonia swelling treatment was done. transparency of CMC solution from LBKP was hardly effected, but in case of NBKP gradually increased with increasing concentration of $NH_4OH$. 4. When ammonia swelling treatment was done, viscosity of CMC solution was higher than that of CMC solution without ammonia swelling treatment. Especially, CMC of high viscosity could be manufactured in 5%, 10% concentration levels of $NH_4OH$. 5. In CMC manufactured from domestic NBKP, CMC at the range of 0.40 to 0.50 in DS was dispersed easily and quickly dissolved, and CMC at more than 0.50 in DS was dispersed slowly in water solution. 6. In comparison with commercial domestic CMC used as a food additive, CMC manufactured from domestic NBKP was higher in DS, and was lower in viscosity and transparency.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.37 no.2 s.110
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• pp.78-86
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• 2005

Hwaseonji(Korean traditional paper) used for writing and painting has been made from the mulberry bast-fiber and the short-length fiber pulps, wood pulps. However, besides wood pulps, other short-length fiber pulps also can be used instead of wood pulps. Hence, this research was carried out to make the various Hwaseonjis with the different properties, using the five kinds of short-length fiber pulps respectively. The short-length fiber pulps used in this research were softwood bleached kraft pulp(SwBKP) hardwood bleached kraft pulp(HwBKP), rice-straw bleached sulfite pulp(RsBSP), bamboo bleached kraft pulp(BbBKP) and recycled pulp from vellem paper(RP). And, the mixture ratios of the mulberry bast-fiber pulp and short-length fiber pulps were 100:0, 80:20, 60:40, 40:60 and 20:80. After various Hwaseonjis were made from different mixtures mentioned above with hand-made method, physical properties and chinese ink blot property of each paper were measured. The strengthes were the highest in the Hwaseonji made from the mixture of the mulberry bast-fiber pulp and SwBKP. However, chinese ink blot property and smoothness were better when RsBSP, BbBKP or RP were mixed into the mulberry bast-fiber pulp. As a result, the various kinds of Hwaseonjis which the users can choose based on their needs were made.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.231-237
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• 2006

Grease barrier food containers are commonly used for packaging of fast food, cooked food, and food in general. Greaseproofing is also used for certificate paper and label paper etc. Different pulp raw materials, due to their different fiber morphology and chemical compositions, produce papers of varying characteristics. We used optical photomicroscopy and fiber analysis data to evaluate fiber morphology and traits under various beating conditions in order to understand which pulp raw materials produced superior greaseproofing property when a fluorinated greaseproofing agent was added internally. The experiment studied 9 species of pulps, including 2 softwood (northern pine and radiata pine) bleached kraft pulps which were beaten to 550 and 350 mL CSF, respectively; 3 hardwoods (eucalypts, acacia, mixed Indonesian hardwoods) bleached kraft pulps which were beaten to 450 and 250 mL CSF, respectively; and nonwood fibers of reed, bagasse, and abaca. A fluorinated greaseproofing chemical at 0.12% dosage with respect to dry pulp was added to each pulp preparation and formed handsheets. A total of 67 sets of handsheets were prepared, and their basis weights, thickness, bulks, opacities, wet opacities, air resistance, water absorption and degrees of greaseproofing were measured for an overall evaluation of pulp and freeness on greaseproofing papers. The experimental fiber length, coarseness and distribution characteristics and the greaseproofing results suggest that softwood pulps (radiate pine > northern pine) were superior to hardwood pulps (eucalypts > acacia > mixed Indonesian hardwoods). The unbeaten pulps gave papers with high porosities and nearly devoid of greaseproofing property. Greaseproofing is proportional to air resistance. Among the nonwood fibers, bagasse had the best greaseproofing property, followed by reed and abaca was the poorest. With regards to waterproofing property, hardwood pulps (mixed Indonesian hardwoods > acacia > eucalypts) were better than softwood pulps (northern pine > radiate pine). Among the Nonwood fibers, reed had the highest waterproofing property, and it was followed by abaca, while bagasse had the poorest waterproofing characteristic. In summary, bleached kraft northern pine, eucalypts and reed pulps were best suited for making greaseproofing papers, Freeness of the pulps should be kept at $200{\sim}280mL$ CSF for optimal performance.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2003.11a
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• pp.148-153
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• 2003

The influence of sizing, fiber and pigment type on coating penetration, using commercial paper and two types of handsheets as the base paper which were prepared from thermomechanical pulp(TMP) and hardwood bleached kraft pulp(KP) sized internally with alkyl ketone dimmer(AKD), was studied in terms of characteristics of coating holdout. Laboratory rod draw down coater was used for surface sizing and coating application. Characterization of coating penetration was done by measuring the roughness of the backside of coating layer. The backside of the coating was exposed by dissolving the fibers in a solution of cupriethylenedimine(CED). Data show that internal sizing of base paper is effective and surface sizing is more effective to prevent coating penetration. Comparing between the two types of base papers, backside roughness of coating layer of TMP sheet is much larger and sizing is more effective to reduce coating penetration than those of KP sheet. With regard to pigment type, clay is more effective than calcium carbonate for better coating holdout.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.31 no.2
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• pp.34-41
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• 1999

Adsorption of cationic polyacrylamide dry strength resins onto the surface of papermaking fibers and fines is critical for their effective utilization. Since dry strength resins are frequently employed when recycled fibers containing a great deal of fines are used as a raw material, their adsorption characteristic onto the recycled fiber fines is of great importance. In this study, effects of recycling on adsorption characteristics of cationic polyacrylamide onto primary and secondary fines were examined. Never dried bleached hardwood kraft pulp was beaten and dried for recycling. In each recycling step the adsorption characteristic of a cationic PAM onto primary and secondary fines was evaluated by kjeldahl nitrogen analysis method. The influence of recycling on water retention value and carboxyl content along with the sheet density and tensile strength was examined. Secondary fines of never dried pulp adsorbed twice as much of C-PAM as the primary fines, however, the adsorption capacity of the secondary fines decreased rapidly during the course of recycling and showed lower adsorption capacily than primary fines.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.4
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• pp.21-27
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• 2014

As a part of the study on manufacture of low density paper by organic bulky agent treatment, the effects of cationic fatty acid bulky agent on physical and optical properties of handsheets were elucidated. The research on change of physical and optical properties of paper samples according to bulky agent concentration, pulp type, and pulp combination were carried out. The results demonstrated that an increase of the concentration of cationic fatty acid bulky agent was proportional to an increase of the bulky properties of paper samples while tensile strength decreased. Also, the more the treated concentration of cationic fatty acid bulky agent increased, the more the ISO brightness of paper samples decreased while the opacity increased. The effectiveness of bulky agent with softwood bleached kraft pulp (SwBKP) was higher than that with hardwood bleached kraft pulp (HwBKP). In addition, the effectiveness with mixed pulps was higher than that with single pulp.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.4
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• pp.69-75
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• 2014

Effects of alkali swelling of HwBKP (hardwood bleached kraft pulp) at a low concentration below 2 percent (based on the oven-dried weight of pulp) on handsheet properties were investigated. Swelling treatment of HwBKP was performed at various low NaOH concentrations with/without beating. Then, the changes in handsheet properties were evaluated in terms of bulk, optical and strength properties. It was found that bulk was slightly increased when the alkali concentration was increased. When the pulp was only swollen without beating, paper optical and strength properties was slightly decreased or not changed with alkali concentration. When the pulp was alkali-swollen after beating, paper strength and opacity showed almost no changes while brightness was increased. When the pulp was beaten after NaOH swelling, alkali concentration showed almost no effect on brightness and opacity of paper. Paper strength was slightly decreased with alkali concentration, suggesting that alkali pretreatment before refining could adversely affect refining efficiency.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.46 no.3
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• pp.65-72
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• 2014

In this study, effects of alkali swelling at low concentration below 2 percent on properties of hardwood bleached kraft pulp (HwBKP) were elucidated. Swelling treatment of HwBKP was performed at various NaOH concentrations with/without beating. Then, the swelling characteristics of pulp fiber was evaluated by measuring the solvent retention values such as water retention value (WRV) and isopropyl alcohol retention value (LRV). It was found that fiber characteristics were influenced by NaOH swelling even at low alkali concentration and beating treatment as well. The values of WRV and LRV were decreased when the alkali concentration was increased. It is the result from the decreased acidic groups of pulp which were formed during beating. The acidic groups could be neutralized and then removed by alkali. The difference between WRV and LRV was decreased with increasing alkali concentration while the difference was increased when the alkali swollen pulp was beaten. In addition, the crystalline structure of HwBKP was almost not changed while the crystallinity was influenced by swelling treatment at a low alkali concentration.