• 펄프종이기술
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• 제33권3호
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• pp.1-8
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• 2001

Paper consists of fiber network and paper properties were highly affected by fiber characteristics. Many researchers have tried to relate fiber and paper properties. Softwood and hardwood fiber's are quite different in their properties. Generally, softwood fiber's are longer and more flexible than hardwood fibers. At present, many paper mills make mixed paper with softwood and hardwood fibers except for special grade. During fracture some fiber's are broken and others are pulled out. In this paper, the number of broken and pulled out fiber's during fracture is analyzed depending on the mixing ratio of softwood and hardwood fiber's. Fiber length, curl, kink, coarseness, WRV and formation index were measured. Double-edged strength samples were prepared to observe the number of broken and pulled out fiber's. Mixed paper strength was decreased with increasing hardwood fibers ratio. During fracture, softwood fiber's were more likely broken and hardwood fibers were more likely pulled out. The strength of paper which consists of softwood fibers was determined by fiber's broken strength and that of hardwood fibers by fiber's debonding strength. Paper strength was changed depending on the fiber's bonding capability. If the fiber is longer and more flexible, the fiber network becomes stronger and stiffer.

• 펄프종이기술
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• 제34권5호
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• pp.49-55
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• 2002

A new method is proposed for the on-line measurement of the fiber orientation of sheet materials. The measurement of fiber orientation is very important in manufacturing paper sheets, non-woven fabrics, and glass sheets, because fiber orientation strongly affects product properties represented by, for example, dimensional stability of paper. A method developed in this research utilizes anisotropy of dielectric constants of sheet materials as a key characteristic to determine the fiber orientation. The new on-line sensor, consisting of 5 microwave dielectric resonators set in different directions, was designed to detect the fiber orientation while paper is running with high speed on a paper machine. This sensor can determine the direction and the degree of fiber orientation from the measured direction of the maximal dielectric constant and its variation, respectively. The fundamental performance of this system was examined by the static measurement of printing grade paper, which gave a satisfactory result. Then, the dynamic measurements were done at a speed of 1,000 m/min by using a high-speed test-coating machine.

• 펄프종이기술
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• 제43권5호
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• pp.27-33
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• 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.

• 펄프종이기술
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• 제40권3호
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• pp.30-35
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• 2008

Mechanical properties of paper mulberry bast fiber handsheets were investigated to study the characteristics of bast fiber in terms of being suitable for modern paper making process. Tensile, tear and burst strength of handsheets made from bast fiber of paper mulberry were better than those of NBKP handsheets. Smoothness of bast fiber was higher but stiffness was lower than NBKP. Sizing performance of bast fiber were worse. 3D image analysis showed that handsheets of bast fiber had inferior formation and more pores comparing to NBKP.

• 한국연초학회지
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• 제22권1호
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• pp.99-106
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• 2000

In order to investigate the applicability of lyocell fiber to filter paper, papper sheets were manufactured with the addition of lyocell fibers in various length(1.5 denier: 2, 3, 4mm) and content(10, 30, 50%) and their physical characters, such as fibrilation rate, adsorption efficiency of methylene blue(MB), paper formation, and crimping ability, etc, were tested. The level of main fibrilation from lyocell fiber was higher in wet beating process than that in free beating because of the higher strength of lyocell fiber compared with wood fiber. Fibrilation could be observed at the degree of beating over 30$^{\circ}$ SR in wet beating with Valley beater. The air permeability and tear factor of the paper increased and the paper formation index decreased according to the increase of fiber length. The weak binding force of lyocell fiber in spite of its higher fiber strength, might be a limitng factor in addition of lyocell fiber to the natural wood pulp in manufacturing the paper having the needed physical properties. High contents of wood pulp decreased air permeability, the breaking length, tear factor, the bursting strength, and paper formation index in paper sheets. As the contents of lyocell increased from 10% to 100%, the adsorption efficiency of MB was elevated to 1.7-7.9 times compared with that in 100% wood pulp. But the length of lyocell fiber did not affect the MB adsorption.

• 펄프종이기술
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• 제45권6호
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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.

• Fibers and Polymers
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• 제7권2호
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• pp.191-194
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• 2006

This paper adopts nonlinear vibration method to analyze the fluctuation process of fiber movement. Based on Hamilton Principle, this paper establishes differential equation of fiber axial direction movement. Using variable-separating method, this paper separates time variable from space variable. By using the disperse movement equation of Galerkin method, this paper also discusses stable region of transition curve and points out those influencing factor and variation trend of fiber vibration.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2006년도 PAN PACIFIC CONFERENCE vol.1
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• pp.161-166
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• 2006

A new fiber orientation sensor has been developed and tested on an actual paper machine to demonstrate its capability to function as a real-time monitoring system. First, we demonstrate the ability of the sensor system to detect the change in the fiber orientation angle while the sensor head, and not the paper, was intentionally rotated from $-90^{\circ}\;to\;+70^{\circ}$ with respect to the paper-traveling direction. Next, we demonstrate that this system can successfully detect the change in the magnitude and angle of fiber orientation in running paper when the direction of material flow on the wire was changed on the paper machine. The angle and magnitude of fiber orientation were independently confirmed by SST and MOA measurements. Furthermore, we found that the system was capable of measuring the basis weight and the moisture content of running paper while detecting the angle and magnitude of fiber orientation.

• 펄프종이기술
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• 제42권5호
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• pp.37-46
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• 2010

This study was carried out to develop new application field and obtain the basic data of mixed paper with wood pulp and chitosan fiber for producing functional paper. Two types of wood pulp, such as SwBKP and HwBKP, were mixed with chitosan fiber. Physical and optical properties, water vapor absorption, air permeability, antibacterial activity and ash were measured. And the surface morphology of manufactured paper was observed using SEM. The results are as follows. It was revealed that density, breaking length, burst index, tear index, folding endurance and brightness were reduced but water vapor absorption and air permeability were on the rise in the structural view of SwBKP according to increasing the chitosan fiber ratio. Those HwBKP added chitosan fiber were great not only in the strength but also water vapor absorption and air permeability except for brightness. The water vapor absorption was lower and the air permeability was higher in the HwBKP added various chitosan fiber ratios than those with no chitosan fiber. It is estimated that these properties were related with various mixed rate of chitosan fiber. Particularly, air permeability was strongly dependent on the mixed rate of chitosan fiber. The chitosan fiber has superior antibacterial property, comparing with wood fiber. Adding chitosan fiber to the wood pulp was found to have an excellent antibacterial activity, more than 90%. The ashes were determined within 0.5%. Special bonds between chitosan fiber and wood pulp was observed by SEM and it means that the chitosan fiber were combined equally in the interior of wood pulp. In conclusion, mixing wood pulp with chitosan fiber can not only improves the quality of paper but also extend the usage of paper as a functional paper by using inherent property of chitosan. After all, production of functional paper added chitosan fiber is expected for new valuable industry of paper.

• 펄프종이기술
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• 제31권1호
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• pp.39-45
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• 1999

Refining in papermaking plays an important role in changing fiber properties as well as paper properties. The major effects of refining on pulp fibers are internal and external fibrillation, fiber shortening, and fines formation. Many workers showed that internal fibrillation of the primary refining effects was most influential in improving paper properties. In particular, refining produces separation of fiber walls into several lamellae, thus causing fiber wall swelling with water penetration. This leads to the increase of fiber flexibility and of fiber-to-fiber contact during drying. If the fibers are very flexible, they will be drawn into close contact with each other by the force of surface tension as the water is removed during the drainage process and drying stages. In order to study the effect of fiber wall delamination on paper properties, cross-sectional image of fibers in a natural condition had to be generated without distortion. Finally, it was well recognized that confocal laser scanning microscope (CLSM) could be one of the most efficient tool for creating and quantifying fiber wall delamination in combination with image analysis technique. In this study, the CLSM could be used not only to observe morphological features of transverse views of swollen fibers refined under low and high intensity, but also to investigate the sequence of fiber wall delamination and fiber wall breakage. From the CLSM images, increasing the specific energy or refining decreased the degree of fiber collapse, fiber cross-sectional area, fiber wall thickness and lumen area. High intensity refining produced more external fibrillation.