• Textile Coloration and Finishing
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• v.10 no.3
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• pp.10-19
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• 1998

This paper investigates the change of mechanical properties and thermal shrinkage in commercial multi-filament PET(polyethylene terephthalate) , namely, regular yarn, POY, DTY and composite yarn. To determine changing the effects of processing steps, these were examined at three steps process simulation conditions. The first step is sizing simulation$(S-1\;step\;:\;130^\circ{C}\times2\;min$., hot air treatment under 0.1 gf/d load), the second step is scouring simulation$(S-2\;step\;:\;100^\circ{C}\times20\;min$., boiling water treatment under free tension)and final step is setting simulation$(S-3\;step\;:\;180^\circ{C}\times2\;min$., hot air treatment under free tension). Regular yarn in multi-step treatment showed higher shrinkage at S-3 step and DTY showed higher in at S-1 step. While POY was relaxed at S-1 step, composite yarn showed different shrinkage properties depending on composite yarn type. Mechanical properties showed good relationship with shrinkage : high shrinkage makes initial modulus decrease and bleating strain increase. It also makes decreasing yield strain and yield stress decrease.

• Journal of the Korean Society of Clothing and Textiles
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• v.41 no.1
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• pp.84-97
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• 2017

Water vapor and thermal transmission properties of high emotional garments are important to evaluate wear comfort; in addition, the measuring methods of these properties are also critical for breathable and warm suit fabrics. In this study, the water vapor and thermal properties of composite yarn fabrics made of CoolMax, Tencel, and Bamboo fibers with filaments were measured and compared according to the measuring method. Water Vapor Transmittance (WVT) of the fabric woven by the sheath/core composite yarn in the warp direction was the highest due to the small staple fiber volume in the sheath/core yarn structure and high air voids in the sheath/core yarn fabrics. This property was also the highest in fabrics woven by bamboo staple yarns in the weft direction, and was the lowest on hi-multi filament fabrics. However, water vapor resistance ($R_{ef}$) of these fabrics by KSK ISO 11092 showed the opposite results to the water vapor transmittance method ($CaCl_2$ method); in addition, its correlation coefficient was low. The correlation coefficient between $R_{ef}$ and the drying rate was 0.719; therefore, the measurement mechanism of $R_{ef}$ is analogous to the drying property measurement. The thermal conductivity of the fabrics woven with compact staple yarn showed a high value; however, the hi-multi filament fabric showed low thermal conductivity. Therefore, fiber characteristics affect thermal properties more than yarn structure. The correlation between thermal property and moisture transport was also low. This study showed that: water vapor transmittance was active at the loose yarn structure, dry heat transport was vigorous at the compact yarn structure, and heat transport was affected more by fiber characteristics than yarn structure. In conclusion, sheath/core composite yarns were relevant to the high absorptive cool suit along with siro-fil and CoolMax/Bamboo staple yarns that were relevant to the heat diffusive cool suit.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.2 s.150
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• pp.275-285
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• 2006

The purpose of this study was to examine the change of dyeing ability by K/S values, when dyed in different twisting processes and by one bath system and two bath system, to find possible ways of minimizing the color difference between cotton and polyester in composite yarn. The two types of composite yarn, which had one setting process(CP1) and two setting processes(CP2) were dyed with reactive/disperse dyes in both one bath dyeing system and two bath system. The dyeing ability according to the two different twisting processes was measured, and the values of the CP1 were higher compare to the values of CP2 in both one and two bath dyeing systems. This is because CP1 applied only one setting could shrink dyeing process at 130$^{circ}C$. This shrinkage increased the number of twists in the unit length and increased the yarn density, and this is the reason that the K/S values were measured higher than those of CP2. In wet shrinkage test, in opposition to CP2 only had 0.76$\%$ of the shrinkage rate, CP1 had 3.00$\%$ of the shrinkage rate. Also, the dyeing ability according to the two different dyeing methods was measured, and the values of CP1 and CP2 were both higher when dyed in two bath system. On the other hand, the color differences between cotton and polyester in composite yarns, were smaller for CP2 than that for CP1 and were also smaller in two bath dyeing system than in one bath dyeing system. Therefore, the ways of minimizing color difference between cotton and polyester in composite yarn are to apply enough setting in order to minimize shrinkage in dyeing process and to choose two bath dyeing system.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.04a
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• pp.199-210
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• 2000

복합재료의 성형 공정 중 하나인 Filament Winding 공정에 열가소성 기지재료인 폴리프로필렌(Polypropylene)과 강화섬유인 유리섬유로 이루어진 Commingled Yarn 을 이용한 연구를 수행하였다. 함침 과정을 해석하기 위한 계산모델을 제시하였다. 그리고 위의 모델링을 해석하는 데 필요한 복합재료 내의 온도 분포를 수치해석을 통해 계산하였고 실험을 통해 이를 검증하였다. 온도계산 결과를 함침도 예측에 이용하였다. 모델링을 통해 Filament Winding 공정의 주요 공정 변수를 찾아내었고 제시한 모델을 검증하기 위해 직접 Filament Winding 실험 장치를 제작하여 제품을 생산하고 모델과 비교하였다. 제작된 시편으로부터 함침도를 계산하는 방법을 제시하였다. 그 결과 함침도에 관해서 실험 결과가 모델과 그 경향이 뚜렷이 일치함을 확인하였다.

• Fashion & Textile Research Journal
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• v.5 no.4
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• pp.408-412
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• 2003

The micro structure of POY was modified and a wool-like touch yarn of composite fibers with different shrinkage was made. With this yarn 12 different fabrics with wool like touch were prepared. The characteristic physical property changes of the fabrics examined are as follows: 1. In all cases, the initial high shrinkage stages were observed in hot water treatment and the 3D images of complex multilayer of typical doubling fibers with different shrinkage were also observed in hot air treatment of 170C. 2. The tensile strength changes of satin and plain fabrics with the change of twist count showed similar behavior. However, WT's were slightly higher and RT's was lower in twill and satin fabrics than those in plain fabric. 3. Since a slight decrease of B's of twill fabric found with increasing twist count under given experimental condition, it could be influenced on the anti-drape stiffness was decreased and flexibility was increased. 4. A significant decrease of G values was observed in the twist count 800-1000 T.P.M However, in the twist count higher than 1000 T.P.M G values observed were kept nearly constant. 5. MIU of plain and twill fabrics showed a drastic decrease at the twist count higher than 1000 T.P.M.

• Textile Coloration and Finishing
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• v.18 no.1
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• pp.33-43
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• 2006

The purpose of this study was to eximine the effect of different yam twisting methods on mechanical properties and 3D CAD images of plain knitted fabrics made of composite yarns. Six yams were used in this study: four different composite yams of the six consist of acetate and functional polyester (Poly-m) with the ratio of 70:30, and the rest two are the original acetate $100\%$ yam and the poly-m $100\%$ yarn. The four kinds of composite yarns were processed in combinations of twisting processes such as interlacing, false twisting, two for one twisting, combined twisting and single covering, and the two original yams were knitted without any twisting process. Sixteen mechanical properties of all the six knitted fabrics, knitted under the same knitting conditions, were measured by KES-FB system with the outer knit condition. The results were as follows; 1) When the sample applied with the false twisting process at the temperature as high as $220^{\circ}C$, ENT, B, HB, G and RC values of samples increased which leads to increasing dimensional stability. 2) To gain the high bending and shear properties in the single covering process, selecting the core yarn with such properties is the most important factor. 3) Interlacing process effected to increase RC value. 4) False twisting process after interlacing process gave bulkiness and un-interlaced part in yam was increased SMD value. The SMD value of the kilted fabric of the composite yarn, which was put through the combined twist process, was higher than those of which simple process such as the two for one twist or the single covering process applied. In order to achieve the silk-like surface feel of knitted fabric, the sin91e covering process is recommended. 5) Examining the simulation images of the knifed fabrics of composite yarn, which were generated by the 3D CAD system based on the mechanical properties of the fabric, led that appearance could be changed as different twisting methods were applied.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.90-93
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• 2005

A thermal model of carbon spun yarn and its composite is presented. Based on voxelization method, the unit cells of spun carbon yam and its composite are divided into a number of volume elements and the local material properties have been given to each element. By using Finite Difference Method, temperature distribution in the unit cell can be obtained. Effective thermal conductivity of unit cell is calculated using the temperature distribution and thermal conductivities of local elements.

• Journal of the Korean Society of Clothing and Textiles
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• v.30 no.2 s.150
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• pp.255-265
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• 2006

The purpose of this study was to examine the dyeing properties of four kinds of composite yams that were twisted in different processes. The composite yarns consist of acetate and functional polyester in ratio of 70 : 30. The composite yams were dyed at 100$^{circ}C$ and 125$^{circ}C$ using three types of dyes, disperse dyes for acetate fiber, PET fiber and PET-acetate blended fiber, in the three primary colors. The exhaustion($\%$) and K/S value were observed for each case. Also the effects of four different twisting processes to dyeing properties and physical properties were examined. Regardless of twisting methods, the composite yarns that were dyed at 125$^{circ}C$ had higher exhaustion($\%$) than those were dyed at 100$^{circ}C$ with all three types of dyes; However, tendency of the K/S value after reduction cleaning process was measured at 100$^{circ}C$ and the value measured 125$^{circ}C$ had a great difference with disperse dyes for acetate and dyes for PET. The difference of the K/S values of composite yarns, when dyed at 100$^{circ}C$ and 125$^{circ}C$ with disperse dyes for PET-acetate blended fiber, was almost negligible. According to twisting methods K/S values were in the following order: AP1 > AP3 > AP4> AP2. This means that AP1, treated at 220$^{circ}C$, had the highest K/S value and K/S value becomes higher as the yam is higher twisted and becomes lower as lower twisted. On the other hand, the dry shrinkage and wet shrinkage showed low shrinkage rate when the twist was high and steam setting temperature was high.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.22 no.2
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• pp.416-427
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• 1998

Unidirectional commingled-yarn-based carbon fiber(CF)/polyamide(PA) 6 composite was fabricated under molding pressures of 0.4, 0.6 and 1.0 MPa to study its flexural deformation and fracture behavior. Fiber/matrix interfacial bonding area became larger with an increase of molding pressure from 0.4 to 0.6 MPa. For molding pressures .geq. 0.6 MPa, good flexural performance of similar magnitudes was attained. For the fracture test, four kinds of notch direction were adopted : edgewise notches parallel (L) and transverse (T) to the major direction of fiber bundles, and flatwise notches parallel(ZL) and perpendicular(ZT) to this direction. Nominal bend strength for L and ZL specimens exhibited high sensitivity to notching. ZL specimens revealed the lowest values of the critical stress intensity factor $K_c$ which was slightly superior to those of unfilled PA6 matrix. Enlargement of the compression area for T specimens was analyzed by means of the rigidity reduction resulting from the fracture occurrence.

• Steel and Composite Structures
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• v.42 no.4
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• pp.489-499
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• 2022

This paper proposes a numerical optimization method to design the mesoscale architecture of textile composite for simultaneously enhancing mechanical and thermal properties, which compete with each other making it difficult to design intuitively. The base cell of the periodic warp and fill yarn system is served as the design space, and optimal fibre yarn geometries are found by solving the optimization problem through the proposed method. With the help of homogenization method, analytical formulae for the effective material properties as functions of the geometry parameters of plain-woven textile composites were derived, and they are used to form the inverse homogenization method to establish the design problem. These modules are then put together to form a multiobjective optimization problem, which is formulated in such a way that the optimal design depends on the weight factors predetermined by the user based on the stiffness and thermal terms in the objective function. Numerical examples illustrate that the developed method can achieve reasonable designs in terms of fibre yarn paths and geometries.