The authors have measured a variation of the stitch area of knit fabrics, with an image analyzer, to determine a systematic dimensional change of the stitch caused by the direction of an external force. A tendency of the variation has been discussed with the following conclusions: 1) A slight deformation and its tendency can be determined by the measurement of a variation of stitch area of knit fabric on which a uniform deformation is exerted. 2) A relationship between the relative area of the neighboring stitches is determined at the time of the first deformation regardless of an external force. Large and small stitches tend to occur alternatively. A stitch with small variation tends to be located next to a stitch with much variation. 3) The distribution of variation depends on the direction of an external force. A space area surrounded by a sinker loop varies more greatly than that surrounded by a needle loop.
In order to investigate the preventive mechanism of α-Fe2O3 particles deposition on fabrics, the concentration of α-Fe2O3 particles and shaking rate of soiling bath have been discussed under the standard soiling conditions. (1) As the concentration of α-Fe2O3 particles in soiling bath increased, the degree of α-Fe2O3 particles deposition increased for both cotton and polyester fabrics and attained equilibrium at the concentration of 0.05wt%. Although the degree of deposition on polyester fabric was higher than that of cotton fabrics at a lower concentration, the degree was reversed at a higher concentration. (2) The behavior of α-Fe2O3 particles deposition on fabrics was similar to Langmuir type. Cotton fabric showed Stype Langmuir and polyester fabric showed L-type (typical Langmuir) in the lower concentration. Saturated equilibrium adhesion of α-Fe2O3 particles was 13.4mg/g on cotton fabric and 11.5mg/g on polyester fabric. (3) As the shaking rate of soiling bath was changed, three stages have been observed in the proceeding of soiling. At first, slow region (the degree of soiling was small) appeared. At the second step, fast region (the soiling was accelerated in proportion to the shaking rate) exists. And finally, saturated region appears. (4) It is considered that dispersion and coagulation of α-Fe2O3 particles occurred by the increase of shaking rate in addition to the growth of contacting chance between α-Fe2O3 particles and Fabric.