ASTM D2612-99(2018)

5.1 Fiber cohesion is related to the resistance to drafting encountered during textile processing and is affected by such fiber properties as surface lubrication, linear density, surface configuration, fiber length, and crimp.

5.2 Fiber cohesion is affected by the alignment of fiber in sliver in addition to the factors listed in 5.1. A half turn of twist in a 140-mm specimen has been found to increase the breaking force by 30 % and a full turn by 60 %. For this reason, care must be exercised in precise mounting of specimens.

5.3 For the same reason given in 5.2, card sliver gives a different breaking tenacity than draw sliver of the same fiber. Fibers are more aligned in draw sliver, resulting in lower cohesion.

5.4 Increasing the gage length of test specimens reduces the breaking force and apparent cohesion.

5.5 The mathematical relationship between the observed value for breaking tenacity and processability has not been established, but the observed values can be used in comparing various fiber characteristics on a relative basis.

5.6 This method for measuring fiber cohesion in sliver or top (static tests) is not recommended for acceptance testing because it is an empirical method which must be followed explicitly. Results obtained under other conditions cannot be expected to be comparable.

1.1 This test method describes the measurement of fiber cohesion as the force required to cause initial drafting in a bundle of fibers in sliver and top. The observed cohesive force required to separate the fibers is converted to cohesive tenacity based on the linear density of the specimen.

1.2 The values stated in SI units are to be regarded as standard. Inch-pound units appear in parentheses for information only.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.