GB/T 3291.1-1997 in English

1 Scope

This standard specifies the terms related to properties and index tests for fibres and yarns.

2 Definitions

For the purposes of this standard, the following definitions apply.

2.1 cotton maturity
thickening or plump extent of cotton fibre cell wall

2.2 dead fibre
the fibre with cell wall thickness equal to or less than one fifth of the maximum width after expansion of cotton fibre as required, which is in different forms, e.g. untwisted flat ribbon or twisted flat ribbon

2.3 thin-walled fibre
the fibre in unconformity with mature fibre or dead fibre characteristics after expansion of cotton fibre as required

2.4 immature fibre
the fibre showing spiral or flat ribbon with cell wall as thin as transparent after expansion of cotton fibre as required, with cell wall thickness less than one quarter of its maximum width

2.5 normal fibre
the club-shaped fibre showing discontinuous middle cavity and free from obvious twist after expansion of cotton fibre as required

2.6 mature fibre
the approximately club-shaped fibre free from convolution after expansion of cotton fibre as required, with cell wall thickness greater than or equal to one quarter of its maximum width

2.7 degree of fibre wall thickening
the ratio of the actual cross-sectional area of fibre cell wall to the circular area of identical perimeter

2.8 maturity coefficient
one index representing the mature degree of cotton fibre, whose value is determined according to the ratio of cotton fibre middle cavity width to cell wall thickness

2.9 mature ratio
the ratio of thickening degree of cell wall to the 0.577 standard thickening degree selected artificially

2.10 percent maturity
the average percentage of the number of mature fibres to the total number of fibres in cotton specimen

2.11 micronaire value
under specified conditions, the measurement of air permeability of cotton fibre sample, which is a composite indicator reflecting cotton fibre fineness and maturity, expressed in micronaire value. The scale division of micronaire value is subject to the micronaire value range of standard cotton designated by international association

2.12 calibration cotton standard samples
specially-prepared and well-mixed cotton samples serving as standard samples after the approval of standardization administration, with characteristic value and corresponding precision in one or several physical properties

2.13 working cotton standard samples
a batch of well-mixed cotton samples made by professional laboratory with one or several properties determined

Foreword i
1 Scope
2 Definitions
Annex A (Informative) Chinese Index
Annex B (Informative) English Index