Effects of Cotton Fiber Blending and Processing on HVI Measurements—Part I

To obtain a better understanding of the relationships between fiber properties of the constituents of a cotton blend and the processes up to drawing, a review is presented of the effects of blending, orienting, and removing crimp from fibers on HVI test results. These effects are also explored experimentally by testing fibers from the same laydown in bale, card sliver, and drawn sliver form using HVI equipment. Apparent reductions in upper half mean and increases in short fiber content of card sliver may be due to the formation of hooks. Significant correlations between micronaire and fiber properties related to length that are present in bale samples are lacking in both card and drawn sliver samples, suggesting that there is at least one unmeasured factor in this analysis. Measured micronaire values are sensitive to crimp and fiber packing density. Differences in fiber property distributions can have significant effects on HVI measurements, and distributions of single fiber properties of a blend may differ dras tically from those of single bales. Strength tests of blended bundles may not include all constituents in the blend, because only the longest fibers are clamped in the jaws. Testing the fiber population at various stages of processing yields different information about fiber bundles.