Test Methods and Precautions

Cotton Fibre

  • Maturity Coefficient
  • Caustic soda method - Fibres irrigated in 18% caustic soda are examined under microscope. Based on the ratio of lumen width to wall thickness, fibres are classified as Mature, Half Mature and Immature
    Mature (M) - L/W <1
    Half Mature (HM) - 1 < L/W < 2
    Immature (I) - L/W > 2
    Mc = (M + .6*H + .4 * I)/100
    American Method
    Mature (N) - L/W < 2
    Immature (D) - L/W >or= 2
    Maturity Ratio Mr = (N -D)/200 + 0.7
  • Polarised Microscope Method
    Immature - Blue or purple
    Mature - Yellow or Green
  • Differntial Dyeing
    Fibres dyed in boiling dyebath containing .036g Diphenyl Fast Red 5BL and .084g Chloarantine Fast green in 120g of water
    Mature - dyed to red
    Immature Dyed to Green
  • Bundle Strength
  • Trash content
    Shirley Analyser is the standard equipment used for measrement of trash content. The equipment determines
  • Denkendorf Mirodust and Trash Analyser
    enables quick estimation of trash from 25- 30 gms in 12-15min
  • Nep Content
    Neps represent small pin size entanglements of fibres which detract from appearance of yarn and fabric. They take up less dye and show up as specks in dyed fabric. In most cases neps are formed by immature fibres because of their low rigidity. Sometimes neps are also formed because of seed coat fragments which provide nucleus for them.
  • HVI Testing
    Conventional testing involves considerable time and results are not available in time for cotton selection and mixing preparation. High volume Instument(HVI) have speeded up testing substantially and testing of a cotton is completed in about 2-4 minutes. Bale wise testing of cootons is possible and bales with substandard characteristics can be weeded out.HVI determines Upper half mean length or 2.5 and 50% span lengths, uniformity index or ratio, Micronaire and bundle strength. Optional attachments for estimating trash level by optical scanning and colour of cotton and moisture level are available. In Micronaire test HVI requires an approximate weighment of cotton. As an option Macromat which measures both fineness and maturity can be incorporated in HVI. HVI, though rapid, has certain limitations in terms of accuracy of results. These include in case of
  • Man made fibre Filament and Yarn