• 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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• 제30권1호
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• pp.7-17
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• 1998

With the advent of CLSM in the end of 1980s, it has been applied to the field of pulp and paper science in various ways. This study showed the potentials of CLSM In analyzing a change of pulp fiber and paper properties before and after mechanical treatment. In particular, a quantification of internal fibrillation has been done using cross-sectional images of fibers and image analysis technique, then evaluated the effects of fiber wall delamination on fiber and paper properties. It showed that the delaminated fibers were closely associated to development of the interfiber bonding in a fiber network. The CLSM made it possible to investigate a density profile along the sheet thickness, which was created by some papermaking processes like pressing, drying and calendering. Through the attempt to observe the forming procedure of a fiber network during handsheet making, the CLSM images showed that the pressing stage was considered greatly to contribute to generation of interfiber bonding with removing a free water and partly a bound water between fibers. In addition, the CLSM could be used to illustrate not only a surface profile of paper showing the extent of smoothness or roughness, but also a density profile in a B-direction of the network. Finally it became evident that the CLSM could be used as an excellent tool to predict development in fiber and paper properties before and after mechanical treatment during papermaking processes.

• 펄프종이기술
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• 제35권3호
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• pp.79-84
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• 2003

Oriental painting paper (Hwaseonji) was prepared from various kinds of plant fibers and its physical properties were investigated. The fibers used were classified into three different length of fibers; long fiber (<1.8 mm), medium fiber (1.4-1.8 mm) and short fiber (>1.4 mm). The fibers were mixed in the ratio of 15% long fiber, 25% medium fiber and 60% short fiber. The Hwaseonji prepared from mixing of the bamboo or rice straw pulp as a short fiber with the long and medium fibers showed excellent physical properties with a high smoothness and uniformity of Chinese ink blot. Mixing with LBKP as a short fiber was resulted in low physical properties, smoothness and wide ink blot. The properties of Hwaseonji, such as ink absorption, roughness and smoothness, may be predicted from the correlation of density with Chinese ink blot and smoothness.

• 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.

• 펄프종이기술
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• 제42권2호
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• pp.61-66
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• 2010

Corn stalk, one of the most abundant agricultural residue in the world, was examined in this study to use it as an alternative fiber source of wood fiber. In order to find the proper way to utilize corn stalk more efficiently, the morphological properties and the papermaking properties of the, bast fibers and the corn pith, were evaluated respectively. Although the bast fiber fraction showed comparable properties to those for hardwoods in the fiber properties and the papermaking properties, the pith resulted in low brightness and low drainage rate. But the short and flexible fibers in pith fraction led to dense and compact handsheet structure, correspondingly the higher sheet strength. There big differences in properties between bast fiber and pith should be considered for the fully utilization of corn stalk.

• 펄프종이기술
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• 제33권4호
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• pp.35-41
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• 2001

A newly developed functional fiber for textile, Tencel, which is known to have some advantages over wood fiber such as fibrillation, absorbency and so on, was examined to see the possibility of a raw material for hanji. Hanji was manufactured by the conventional handmade method using Tencel of three different fiber lengths with three different levels of mixing ratio of Tencel and paper mullberry fiber, and their physical and calligraphic properties were evaluated and compared with one another. It was needed to develop more efficient beating methods than conventional one such as valley beating for Tencel to be used effectively as a raw material for hanji. It was found out by image analysis that the calligraphic properties of hanji could be improved by mixing of 10 to 20% of Tencel of relatively short-length fiber with paper mulberry.

• 펄프종이기술
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• 제47권3호
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• pp.47-54
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• 2015

In this study, effects of kneading treatment on the properties of hardwood bleached kraft pulp (HwBKP), softwood bleached kraft pulp (SwBKP) and hardwood bleached chemi-thermo-mechanical pulp (HwBCTMP) were elucidated with a laboratory two-shaft kneader. Kneading treatment was performed at 30% (w/w) of pulp concentration and the number of passes through the kneader was adjusted from 0 to 10 passes. Then, changes in properties of pulp fibers were evaluated. It was found that fiber characteristics were influenced by kneading treatment. Fiber length was decreased with kneading while other morphological properties such as fiber width, curl and kink became increased as the number of passes through the kneader increased from 0 to 5 passes. The magnitude of changes in the morphological properties of softwood chemical pulp was the largest, followed by hardwood chemical pulp. The morphological properties of HwBCTMP were little influenced by kneading treatment. Swelling of fiber measured by WRV was increased with kneading except of HwBCTMP.

• 펄프종이기술
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• 제39권1호
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• pp.1-7
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• 2007

Internal fibrillation of pulp fiber is an important factor affecting paper properties. Internal fibrillation of pulp fiber is usually introduced with several kinds of modifications of fiber by the mechanical treatment such as refining, high shear and/or high consistency mixing, etc. Unfortunately there are no standardized methods that can characterize the extent of internal fibrillation and its contribution on the paper properties. The purpose of this study is to try and find the potential methods that can characterize the internal fibrillation of pulp fiber quantitatively. Softwood bleached kraft pulp was treated with Hobart mixer to introduce the internal fibrillation without the significant fiber damage and external fibrillation. The extent of internal fibrillation was increased with the increase of mechanical treatment consistency. Several fiber properties were measured to find the potential means that could characterize and quantity the internal fibrillation. Laminated area could not be used as a means for quantifying the internal fibrillation because of the effect of swelling and the different internal fibrillation behavior at different mechanical treatment consistency. Micro and macro internal fibrillation models were proposed for describing the different behavior for the mechanical treatment at low and high consistencies of pulp. The Internal fibrillation showed good correlation with swelling of fiber wall. This trend was confirmed through the measurement of wall thickness and/or cross section area of fiber. Therefore the internal fibrillation possibly can be described as the indices indicating the change of wall thickness and/or cross section area.

• 펄프종이기술
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• 제30권2호
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• pp.47-54
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• 1998

Refining is one of the most important processes of fiber treatment that provides optical and physical properties of final paper products. The evaluation method of refining progress is usually freeness (CSF) or wetness (SR) test because of its rapidity and convenience. However, there are some deficiencies in using freeness or wetness test to evaluate pulp fibers accurately because its results are more influenced by fines contents than extent of fibers treatment. The objective of this study is to show the deficiency of wetness in evaluating the refining process. For this, beating is done by varying the beating load. Handsheets are made after beating until 25 and $32^{\circ}C$ SR, and then paper properties are measured. Refined fibers are analyzed by fiber length, fines contents, curl, kink, WRV, and zero-span tensile strength. The results show that longer beating time is required to reach the same wetness at lower beating load. There are differences in the average fiber length, distribution curve of fiber length, fines contents, curl, kink, WRV of long fiber fraction, drainage time, and zero-span tensile strength of rewetted sample at different beating load. At the low beating load in the same wetness, apparent density, breaking length, burst strength, and tear strength are higher, while opacity and air permeability are lower than those of the high beating load. Using Page s equation, which shows the relationship among tensile strength, intrinsic fiber strength, and interfiber bonding strength, interfiber bonding strength is calculated and analyzed to explain final paper properties. At $25^{\circ}C$ SR, interfiber bonding strength is only slightly higher at 2.5kgf beating load, while the intrinsic fiber strength is substantially higher. At $32^{\circ}C$ SR, intrinsic fiber strength is a little bit higher at 2.5kgf beating load, and interfiber bonding strength is remarkably higher than those of 5.6kgf beating load. These results can be used to explain the different properties of the final paper at selected beating loads.

• 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.