모델링에 의한 편환 및 합섬 필라멘트 편성물의 광택에 관한 연구

Abstract

The appearance of textile fabrics is of prime importance along with tactile factors such as smoothness, crispness, stiffness, fullness and softness when we deal with the hand evaluation of the fabric. In practice, the quality and performance of fabrics is judged by sighted evaluators, and it is perhaps logical, in attempting to establish an effective fabric objective measurement system. It is worthwhile to make objective measurements that corrlate with subjective assessments made by sight and touch together. However, it is quite difficult to effectively measure and analyze the appearance or optical properties of the fabric surface. There has been significant advancement in synthetic filaments manufacturing technology, including ultra-fine fiber, polymer modification and engineering, control of unevenness of the continuous filaments, and so on. The luster of the filament fabrics can be designed or engineered by various methods, for example, modifying the cross-sectional shape of the monofilament, ultra-fine fiber, inclusion of delustering agents, polymer modification, or surface treatments. In this study, an attempt is made to provide a preliminary approach to the analysis of the luster or gloss properties, which is one part of the optical properies. Incident light ray on finer fiber would reflect less than on thicker fiber. The specimens range from 70/24 nylon filament yarn knitted fabric to 70/68 nylon filament yarn knitted fabric along with 75/75PET filament yarn knitted fabric, which are quite fine melt-spun filaments except for the ultra-fine fibers by conjugate filament manufacturing process. As a first step, a few three-dimensional models based on the Peirce’s model of knit stitch have been proposed and material properties were given, to the models. The refractive index of nylon 6 filament fiber was given to the model, which is 1.54. After setting up the models, rendering was done with a ray-tracing program to endow the model optical behavior based on several physical constants of the material and optical calculations. Goniophotometric measurements of the samples were also carried out employing a goniophotometer made by Tokyo Denshoku at varying incident and receiving angles. Image analyses of the samples were also performed with an optical microscope. It has been shown that the finer diameter model gives off less the gloss while the model of thicker diameter more. The general optical microscopes have some limitations in terms of focusing, working distance, and resolution at highter magnification. Due to these limiting factors, it is sometimes difficult to have a fine focused image of knit structures having rather diverse and varying heights. This could lead to blurred image around the gloss area resulting in less accurate pixel area calculation. The ray-tracing of three-dimensional model might provide sharp focused image which is an inherent property of the methods.