合成繊維・再生繊維集合体の圧縮応力緩和特性

Abstract

In this paper, the compressive stress relaxation properties of twelve kinds of cylindrical fiber assembly made of synthetic fibers such as polyester fibers and poly(trimethylene terephthalate) (PTT) fibers, and regenerated fibers such as cupro-ammonium rayon (cupra) fibers and lyocell fibers are investigated experimentally with regard to sleeping comfort. The results are obtained as follows.(1) Experimental curve of Sγ , residual stress ratio for all samples is expressed approximately by following empirical equation for t > 102 sec.Sγ=σ/σ0= K(a0 - ln t)where, σ : stress at time t (Pa), σ0: initial stress (Pa), t : time(s), K and a0 : constants determined by fiber type and measurement condition.(2) Stress relaxation rate represented by K of regenerated fiber assembly made of cupra and lyocell fibers is high compared to that of synthetic fiber assembly made of polyester and PTT fibers.(3) Compression stress relaxation phenomena of regenerated fiber assembly is expressed by following equation derived from Eyring′s non-linear two element visco-elastic model for 0 < t < 104 sec.Sγ=σ/σ0= K ln [coth {1/2(2e-a0t + B)}]where, K, a0 and B are constants determined by fiber type and measurement condition. In contrast, compression stress relaxation phenomena of synthetic fiber assemblies are not expressed by this equation.(4) Compression stress relaxation phenomena of synthetic fiber assembly are expressed by following empirical equation for 0 < t < 104 sec. σ = βt-α. where, σ : stress at time t (Pa), t : time (s), α and β are constants determined by fiber type and measurement condition.