Journal of Textile Engineering
Online ISSN : 1880-1986
Print ISSN : 1346-8235
ISSN-L : 1346-8235
Volume 58, Issue 6
Displaying 1-2 of 2 articles from this issue
Original Papers
  • Morihiro YONEDA , Chie NAKAJIMA , Akari YANAGIHARA
    2012 Volume 58 Issue 6 Pages 77-88
    Published: December 15, 2012
    Released on J-STAGE: March 08, 2013
    JOURNAL FREE ACCESS
    In this study, a compression stress relaxation phenomena of three-dimensional fiber assembly for futon wadding use is investigated under high humidity condition, which simulates actual sleeping environmental condition. KES-G5 compression tester is used for the compression stress relaxation measurement, and humid air is supplied to the tester with high humidity air generator. Samples used are polyester (PET) staple fiber with round section and with w-shaped section, and cupra-ammonium (cupra) staple fiber. Results are obtained as follows.
    (1) Stress relaxation rate of cupra staple fiber assembly in high humidity condition is large compared to that of standard condition. Change in stress relaxation rate of PET staple fiber assembly between high humidity and standard conditions is not so large.
    (2) Stress relaxation function, Y(t) of cupra staple fiber assembly in high humidity condition is expressed as two stage exponential function.
    Y(t) = A1exp (-t/τ1)+A2exp(-t/τ2).
    where, A1, A2 (n.d.) and τ1, τ2 (s) are constants obtained from experimental curve.
    (3) Stress relaxation function of PET staple fiber assembly in high humidity condition is expressed as power function of time.
    σ = βt
    where, σ: stress (Pa), α and β: constants obtained from experimental curve.
    (4) The effect of high humidity condition on compression stress relaxation phenomena of cupra fiber assembly is discussed based on viscoelastic theory, and compared to that of PET fiber assembly.
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  • Chie NAKAJIMA , Morihiro YONEDA
    2012 Volume 58 Issue 6 Pages 89-97
    Published: December 15, 2012
    Released on J-STAGE: March 08, 2013
    JOURNAL FREE ACCESS
    In this study, a compression creep behavior of three-dimensional fiber assembly for futon wadding use is investigated under high humidity condition, which simulates sleeping microclimate condition. Compression creep tester is used for the measurement, and humid air is supplied to the tester with high humidity air generator. Samples used are twelve kinds of staple fiber made of polyester (PET) fiber with round, w-shaped and hollow section, polytrimethyleneterephtalate (PTT) fiber, cupra-ammonium (cupra) fiber and Lyocell fiber. Results are obtained as follows.
    (1) Compression creep deformation ratio of regenerated fiber assembly is significantly large compared to that of synthetic fiber assembly for high and low stress.
    (2) The order of creep deformation ratio for the same fineness and fiber diameter is as follows. Cupra is the largest, PET with round section follows and PET with w-shaped section is the smallest for fineness of 1.4 dtex and fiber length of 38 mm. PET with hollow section is larger than PET with round section for 6.6 dtex and 51 mm
    (3) There is no significant difference in compression creep deformation ratio for staple fiber assembly made of same fiber material of which fineness ranges 1.3 ∼ 6. dtex and fiber length ranges 38 ∼ 51 mm.
    (4) Compression creep deformation ratio in high stress condition (2156 Pa) is larger than that of low stress condition (1176 Pa).
    (5) Compression creep behavior of staple fiber in high humidity condition is expressed as following equation.
    εt=Y0 ln (vt+1)
    where, Y0 and v are constants derived from measurement curve.
    (6) Y0 is the magnitude of compression creep at a certain time, and Vini(=Y0·v) is the initial tangential rate of creep. Parameters Y0 and Vini is useful for describing compression creep behavior of synthetic and regenerated fiber assembly.
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