Standard Test Method for Overlength Fiber Content of Manufactured Staple Fiber

Importancia y uso:

5.1 The existence of overlength fiber in manufactured staple can cause serious problems in the spinning of these fibers into yarn. Overlength fibers may create problems in carding, but more especially high-strength multiple cut fibers may cause cockling in spinning.

5.2 Since the overlength fibers are caused by dull or damaged cutting knives or by uneven flow of tow to the staple cutter, their existence within the fiber population is not uniform and their occurrence in the population follows a highly skewed distribution.

5.3 Manual methods of determining overlength fiber require much more operator time, and the standard deviations of the test between laboratories and operators are high. Use of the Fibrosampler method greatly reduces both operator time and standard deviation of testing.

5.4 In manufacturing it is important to know if fibers are overlength due to looping of the tow or multiple length due to damaged cutters.

5.5 This method for testing staple fiber for overlength fiber is not recommended for acceptance testing (see 13.1).

5.5.1 In some cases the purchaser and the supplier may have to test a commercial shipment of one or more specific materials by the best available method, even though the method has not been recommended for acceptance testing of commercial shipments. If there are differences of practical significance between reported test results for two laboratories (or more), comparative test should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a minimum, use the samples for such a comparative tests that are as homogeneous as possible, drawn from the same lot of material as the samples that resulted in disparate results during initial testing and randomly assigned in equal numbers to each laboratory. The test results from the laboratories involved should be compared using a statistical test for unpaired data, a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future test results for that material must be adjusted in consideration of the known bias.

Subcomité:

D13.58

Referida por:

D4849-21, D5103-07R24

Volúmen:

07.01

Número ICS:

59.060.20 (Man-made fibres)

Palabras clave:

length; multiple—length staple fibers; overlength staple fibers ; staple fibers ;