AATCC 20A:2017 pdf download.Fiber Analysis: Quantitative
2.1 The procedure given for the removal of nontibrous materials will remove most. but not all, of these components. Each treatment is applicable only to certain categories of these substances and no general scheme can be given that is all inclusive.
2.1.1 Some of the newer finishes may present special problems and the analyst will have to deal with these cases as they arise. Thermosetting resins and crosslinking latices are not only difficult to remove but in some cases cannot be wholly removed without destroying the fiber.
2.1.2 When it is necessary to modify a procedure, or use a new one, one should make sure that the fibrous portion of the specimen under test is not attacked.
2.2 Fiber composition is generally expressed in the laboratory either on the oven-dry weight of the textile as received or on the oven-dry weight of the clean fiber after nonfibrous materials are first removed from the textile before the fiber analysis is carried out, or if the treatments described in Section 9 arc incapable of removing them, any such materials present will increase the percentage of the fiber constituent with which they are removed during the analysis.
When used in commerce for the representation of the nominal fiber content of end use items such as gamients, moisture regain is typically added back to bone dry numbers generated. ASTM D1909, Standard Table of Commercial Moisture Regains for Textile Fibers, can be used for this purpose.
2.3 The procedure for determining fiber composition by mechanical separation is applicable to those textiles wherein the different fibers making up its composition are segregated in separate yams, or plies, in the textile product.
2,4 The chemical procedures for fiber composition described herein are applicable to most of the current, commercial production fibers within each generic class listed. Known exceptions are noted in Table II. However, there may be instances in which a method may not be fully adequate for a newly developed fiber falling within one of the listed generic classes and for re-used and.or physically or chemically modified libers. Caution should he exercised when applying these methods to such cases.
2.5 The microscopical procedures for fiber composition are applicable to all fibers and their accuracy depends to a considerable extent upon the ability of the analyst to identify the individual fibers present. I lowever, owing to the tedious nature of this technique, its use is generally limited to those mixtures which cannot be separated mechanically or chemically; e.g., mixtures of hair and wool and mixtures of cotton, linen, hemp andJor ramie.AATCC 20A pdf download.