공기적층 부직포에서 흡수거동에 대한 연구 (IV) -이종 섬유 집합체에서의 흡수 구조 방정식-

홍철재 한국섬유공학회 2004 한국섬유공학회지 Vol.41 No.2

Structural equation was derived to predict absorption rate in nonwoven webs. The variables considered for the equation were fiber denier, fiber density, fiber blend ratio, fiber contact angle, and web thickness. Experiment was carried out to verify the equation in air-laid nonwovens prepared using polyester and rayon fibers with different blend ratios. The results showed that although there was a difference of approximately an order of magnitude between the calculated and the measured rates, the relationship was linear with a high correlation coefficient.

공기적층 부직포에서 흡수거동에 대한 연구(I) -수직 흡수거동-

홍철재 한국섬유공학회 2002 한국섬유공학회지 Vol.39 No.6

The vertical wicking model for nonwoven materials was developed in a combined form of saturated and diffusion flow modes. In the model, permeability coefficient and capillary pressure were the key parameters describing wicking behavior. For the simulation and experimental test, variables considered were fiber type, web structure, and fluid type. The wetting tension related to the specific fluid affinity of material was newly defined to derive capillary pressures in various types of web structures. In a highly porous web. gravitational effect during the wicking process was significant. The higher the capillary pressure, the higher was the wicking. The model, the methodologies, and the results could be used to design web structure for an optimum wicking performance.

다층 구조 부직포의 유체 투수성에 대한 실험 및 모사분석

홍철재,주창환,김종범 한국섬유공학회 2003 한국섬유공학회지 Vol.40 No.2

In multi-laid nonwoven, the permeability, that has been widely used as an index for fluid transmissivity was investigated considering the structural factors such as the porosity, the pore size and its distribution, and the number of constituent layers. For the experiment, spun-bonded nonwovens with various fiber fineness, web densities, and porosities were used. In a single-layered structure, as the fiber thickness increased, the pore size increased, that resulted in an increase in fluid permeability. In the multi-layered structure, as the number of the constituent layers increased, the effective pore size decreased resulting in a decrease in the permeability. The experimental results could be clearly rationalized from the simulation based on the network model developed in the research.

울/텐셀 혼방직물의 표면가공처리에 따른 감성에 대한 연구

홍철재,남창일,김정규 한국섬유공학회 2000 한국섬유공학회지 Vol.37 No.8

The trend of fashion, which was affected by historical event and culture, plays an important role in determining textile fabrication. The fabrication has been made not only by introducing the newly developed fiber but also by modifying the existing textile materials to impart sensibility to them. In this research, focusing on the latter case, we carried out the fabrication of women clothes specially for fall and winter. A survey on fashion trend through 1990s was made to forecast the fashion trend of 2000 years. Based on the forecasted trend, the fabrication in 2000 was expected to mostly use angora wool that possesses high luster, highly soft touch and highly wet look. However, angora wool is very expensive and thus, it is needed to introduce other fibers the properties of which are almost similar to those of angora. In this research, tencel fiber was introduced to substitute for angora wool. Tencel fabrics prepared were finished chemically with enzyme treatment and phsically with surface raising in a bid to impart to them sensitivity peculiar to angora. In order to characterize the imparted sensitivity, physical properties measured are compressibility, bending, tensile strain, surface properties, and etc. Result showed that the enzyme treated tencel fabric was much closer to the angora fabric than the enzyme untreated tencel fabric.

니들펀칭한 부직포에서 구조적 요인이 유체 투수도에 미치는 영향

홍철재,Hong, Cheol-Jae 한국섬유공학회 1997 한국섬유공학회지 Vol.34 No.9

In-plane flow of fluid in needle punched nonwoven webs was characterized in terms of permeability. The permeability was measured by using GATS (Gravimetric Absorbency Testing System). The variables considered in the experiment were fiber type, fluid type, needling conditions and environmental pressure. Simple structural model was introduced to derive the mean hydraulic pore size which provided criteria for analysis of experimental data. Understanding the mean pore size derived in this research will be useful in structural design of absorbent products of the low thickness such as diaper, sanitary napkin, medical wiper, and so on.

공기적층 부직포에서 흡수거동에 대한 연구(II) -정적 수평 흡수량-

홍철재 한국섬유공학회 2003 한국섬유공학회지 Vol.40 No.5

Absorbent capacity in a highly porous air-laid and needle punched nonwoven web was measured and a model was developed to characterize the capacity. From the model, web thickness was evaluated as a key parameter in determining the capacity. The test cell in GATS(gravimetric absorbency testing system) was modified to measure web thickness during the absorption process. The independent variables considered in the experiment were the fiber type, the fluid type, the web structure, and the environmental pressure. All the variables significantly affected the web thickness and thus absorbent capacity. The results could be clearly rationalized based on the developed model.

소모직물에서 구조적 요인이 쾨적성에 미치는 영향

홍철재,정재석,정성훈 한국섬유공학회 2001 한국섬유공학회지 Vol.38 No.1

Transport phenomena of air, moisture, and heat in fabrics are closely related to the comfort performance from the viewpoint of human physiology. For designing and manufacturing a comfortable cloth, therefore, it would be useful to study structural factors affecting the transport phenomena in fabrics. In this study, the worsted yarns were prepared with different twist levels, and then the fabrics were manufactured with different structural designs, and surface finishing. The change in the twist levels of yarn significantly affects air permeability and heat transfer related to comport performance. The results could be characterized in terms of the cover factor and bulk density of fabric, and rationalized on the basis of known concepts.

섬유집합체에서 이형단면섬유의 유체전달특성에 대한 이론적 고찰

홍철재,Hong, Cheol Jae 한국섬유공학회 2014 한국섬유공학회지 Vol.51 No.1

The cross-sectional shape of a fiber has an effect on the comfort-related fluid transfer properties of a fabric, such as wicking, moisture transfer, and tactile properties. For analysis of these properties via simulation, an equation for the hydraulic pore size was derived on the basis of a structural model. The major variables considered in the equation were the fiber shape factor, the fiber fineness, and the mass density of the fibrous assemblies. Using the pore size from the equation, the permeability and the capillary pressure were calculated and then the horizontal and vertical wicking behaviors, i.e., time dependent activity, were simulated. The results show that the equation can be used to quantitatively analyze the fluid transfer properties in terms of the fiber shape factor, which can provide useful information in designing a fiber structure for improving comfort properties.

팽창성 섬유 집합체의 모세관 흡수에 대한 이론 방정식

홍철재,Hong, Cheol Jae 한국섬유공학회 2018 한국섬유공학회지 Vol.55 No.5

Theoretical equations for quantitative analysis of the effect of fiber swelling on the capillary absorption rate of water-swellable fibers in mixed assemblies were developed. The equation for absorption rate was derived from the Poiseuille equation, whose pressure term was replaced by capillary pressure given as a Laplace equation. The key variables determining the rate were two different capillary sizes of fibrous assembly in dry and wet states. An equation for capillary size was also developed on the basis of the hydraulic radius model. The variables considered in the equation were swelling ratio, cross-sectional shape, fineness, volume density of fiber, and thickness of the assembly. For the experiment, nonwoven webs made of swellable fibers such as cotton, rayon, and superabsorbent fiber blended with hydrophilic polypropylene fiber were prepared. In the experiment, the swelling of the fiber led to a decrease in capillary size, resulting in a decrease in absorption rate. The linear relationship between the rates measured and calculated from the equation shows that the equation could be used to design fibrous assemblies for absorbent products.

파일 직물에서의 유체전달 특성

홍철재,정성훈 한국섬유공학회 2000 한국섬유공학회지 Vol.37 No.1

Fluid transfer was characterized in terms of fluid absorption and evaporation in knitted pile fabrics. Two different test methods for the measurement were newly introduced according to the metabolic conditions of human body. One is the test employing an unlimited fluid source that could be expected to simulate the fluid transfer from a fabric saturated with sweat due to a continuing high metabolic activity. The other is the test employing a limited fluid source that could simulate a low metabolic activity after active movement that causes the exudation of sweat from the body to stop. For the study on the structural factors affecting the fluid transfer in knitted pile fabrics in these two different metabolic conditions, the variables considered are the blend ratio of constituent fibers in the yarn and the length of pile. All of the variables significantly affected the fluid transfer, which could be clearly rationalized on the basis of capillary sorption and desorption curves derived experimentally.