• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.423-426
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• 2006

Paper has fibers and fines network structure and it is strongly affected by interface bonding between fibers. Depending on the inter-fiber bonding, paper bulk is determined. Fines play an important roll in Campbell and consolidation effect through wet pressing and drying operations. Refined Sw-BKP, Hw-BKP and BCTMP fines were used to investigate the fines effect. Wet-web strength, breaking length, scattering coefficient, and hydrodynamic specific volume were measured. According to the result of experiments, chemical and morphological compositions of fines do not strongly affect to wet-web forming, but strongly affect to drying operations which form hydrogen bonding among fiber-fines-fiber matrixes. Paper bulk should be controlled by the extent of hydrogen bonding between fibers during drying operations.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.433-440
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• 2006

A fiber processing method, which might be an alternative for conventional refining process, was introduced. The method consists of repetitive, gentle, mechanical impacts on fiber, and ensued fiber uncurling process. This method was very effective for OCC and BCTMP for increasing WRVs (water retention value) while keeping fiber lengths from shortening. For OCC and BCTMP, gentle mechanical impacts on fibers using Hobart mixer increased breaking lengths and tear strengths simultaneously at fast drainage level, and straightening fibers using kady mill increased those strength properties further. For SwBKP and HwBKP, only mechanical impacts using the mixer were effective on increasing tensile and tear strength at fast drainage, but not kady mill treatment. The strength increases of BCTMP by this alternative fiber processing method were exceptionally high. An extensive engineering development should be followed to actualize this fiber processing mechanism in an energy-effect way.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2005.11a
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• pp.157-171
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• 2005

초지와 인쇄시의 지절은 생산성 또는 운전성의 저하를 야기하므로 최소화해야 한다. 지종에 따라 초지조건이 달라지므로 종이에 가해지는 인장력, 함수율, 초지속도 등을 고려해야 한다. 종이에 있어서 결점 부근에서 일어나는 항복(yield)과 파괴현상을 파괴역학적 관점에서 연구한 바 있다. 초지공정은 섬유 매트 또는 습지에서 점차적으로 수분이 제거되는 과정이며, 인쇄공정은 종이에 물이 가해지는 과정이 있으나, 파괴인성 측면에서 동일한 이론을 적용할 수 있다. 박과 이는 초지시 섬유의 특성, 미세분의 종류 및 함량에 따른 인장 특성 및 파괴 특성에 관한 연구에서 Sw-BKP의 경우 섬유의 파괴가 유도되고, Hw-BKP의 경우 결합면의 파괴가 유도되는 것으로 나타났으며, 미세분 특성에 따른 시험 결과 파괴 인성은 섬유간 실제적 결합이 유도되는 경우 파괴 인성의 향상을 가져올 수 있는 것으로 나타났다. 파괴 역학은 결점 부위의 응력집중 현상에 따른 독특한 파괴 거동으로 지합등과 같은 응력 확산 효과를 기대할 수 없기 때문에 섬유간 실제적인 결합에 직접적으로 의존한다고 할 수 있다.

• Journal of the Korean Graphic Arts Communication Society
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• v.19 no.1
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• pp.64-74
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• 2001

This study is to find the effect of the molecular weight distribution of components on the freeness and physical properties of paper by observing the change of properties according the modification of fibers by using production technology and process technology together to develop additives which can effectively control according to the purpose of paper-making process and by combining low molecular weight cellulase (below MW 20,000; CMC activity 400 unit) with different enzyme's molecular weight and activity and high molecular weight cellulase(MW 20,000∼80,000;CMC activity 90,000 unit) and then process them in Sw-BKP(Softwood Bleached Kraft Pulp) and Hw-BKP(Hardwood Bleached Kraft Pulp) and Cotton Linter Pulp and OCC(Old Corrugated Container) with different properties of pore of surface of fibers respectively, since it is judged that making the appropriate composition ratio of components is necessary in consideration of the properties of fibers and paper-making process.

• Journal of the Korean Graphic Arts Communication Society
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• v.25 no.2
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• pp.45-57
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• 2007

Properties of newly developed paper from Red Algae Pulp (RAP) were examined. The paper samples were prepared according tomixing RAP fiber with wood fibers, HwBKP and SwBKP, to form a paper with $60\;g/m^2$ in weight. It was prepared in three to four different levels of refining degree and pressure so that it can reveal different bulk level in order to clearly compare the opacity at equivalent bulk for each furnish compositions. printability of RAP fiber revealed superior effect on print through repression and initial ink absorption. Those properties are expected to improve further if printability improvement effect due to smoothness improvement is added.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2008.04a
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• pp.129-134
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• 2008

Properties of newly developed paper from Red Algae Pulp (RAP) were examined. The paper samples were prepared by mixing RAP fiber with wood fibers, HwBKP and SwBKP, to form a paper with $60g/m^2$ in weight. It was prepared in three to four different levels of refining degree and pressure so that it can reveal different bulk level in order to clearly compare the opacity at equivalent bulk for each furnish compositions. Printability of RAP fiber revealed superior effect on print through repression and initial ink absorption. Those properties are expected to improve further if printability improvement effect due to smoothness improvement is added.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.47 no.6
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• pp.106-112
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• 2015

Many researchers have proposed analytical methods to measure the adsorption of di-sulpho fluorescent whitening agents (D-FWAs), but practical methods for D-FWA utilization in an actual paper mill have not been established. In particular, the D-FWA adsorption behavior must be monitored in paper mills to ensure the effective use of D-FWAs. This study used the zeta-potential of pulps as an indicator of the adsorption behavior of a D-FWA. We identified the relationship between the actual adsorption of the D-FWA and the zeta-potential of the pulps as a function of D-FWA addition. zeta-potential measurements were then used to analyze the D-FWA adsorption behavior under different conditions of pulp type, conductivity, and pH. The actual adsorption of a D-FWA was proportional to the ${\Delta}zeta-potential$ of the pulps (i.e., the difference between the zeta-potential of a pulp containing no D-FWA and one containing the D-FWA). The ${\Delta}zeta-potential$ of the pulps was therefore adopted for adsorption analysis. A higher adsorption of the D-FWA was observed onto Hw-BKP than onto Sw-BKP because of the shorter fiber length and higher fines content of Hw-BKP. A high conductivity and an acidic pH decreased the D-FWA adsorption because of direct effects of high ion concentrations and low pH on the D-FWA solubility. Therefore, a D-FWA must be added to Hw-BKP under low conductivity conditions and at neutral or alkaline pH to optimize the D-FWA adsorption.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.48 no.1
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• pp.111-118
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• 2016

The effects of pulp beating degree and bulky promotor concentration on the properties of handsheet including a bulk and strength have been investigated during manufacturing of low density paper (high bulk paper) with cationic fatty acid bulky promotor. It was found that paper bulk increased with increasing cationic fatty acid bulky agent concentration, while tensile strength decreased. On the other hand the opacity of handseets also increased with increasing cationic fatty acid bulky agent concentration, while brightness decreased slightly. With increasing pulp beating degree, paper bulk as well as tensile strength increased, while opacity decreased. Brightness did not show a significant difference with increasing pulp beating degree. The highest bulk and strength values were observed when 1.5% (SwBKP) and 2% (HwBKP) of bulky promotor was treated into the 450 mL CSF pulp slurry.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.43 no.5
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• pp.43-48
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• 2011

Filler loading at thick stock was carried out in order to verify if the dual addition of filler can be used as a means to reduce the detrimental effects of filler on the strength properties of paper. PCC was added to 3.5% pulp slurry blended with HwBKP, BCTMP and SwBKP. Cationic starch was used as a fixing agent. The mixture of PCC and pulp was stirred for 5, 10 and 20min. at 1,000 rpm. The remaining PCC was washed out before handsheet making. PCC particles were flocculated and fixed on the pulp fiber and/or space between fibers. It is expected that the flocculation and inclusion of PCC can be helpful to improve the strength properties of paper due to the reduction of detrimental effect in fiber bonding. The distinct tendency in PCC flocculation and fixing on pulp fiber was not observed by the change of cationic starch dosage and treatment time.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2002.05a
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• pp.76-84
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• 2002

Fracture toughness was considered as one of the good estimates of the paper break tendency of paper web in the press room. Paper break on the paper machine is caused by many factors such as paper machine irregular vibrations, impurities in the fiber furnish, shives, and so on. On the paper machine, the solid content of paper web is changing very rapidly from less than 1% to over 95%. We tried to measure the fracture toughness of paper web at different solid contents for providing the fundamental knowledge of paper break. Stretches of wet web were also measured and compared to the fracture toughness changes. Four different fiber furnishes (SwBKP, HwBKP, ONP, and OCC) were refined to different degrees, and at different solid contents (40%, 60%, 80%, and 95%), their fracture toughnesses were measured. Two fracture toughness measurement methods (essential work of fracture and Tryding's load-widening method) were used, and we found they gave identical results. The stretch curves of the wet webs against the axis of solid contents were very similar to the fracture toughness curves of those.