ASTM D629

Test Methods D 629 for the determination of quantitative analysis of textiles may be used for acceptance testing of commercial shipments but caution is advised since information on between-laboratory precision is lacking. Comparative tests as directed in 5.1.1 or by Table D 1909 may be advisable.

In case of a dispute arising from differences in reported test results using Test Methods D 629 for acceptance testing of commercial shipments, the purchaser and the supplier should conduct comparative tests to determine if there is a statistical bias between their laboratories. Competent statistical assistance is recommended for the investigation of bias. As a minimum, the two parties should take a group of test specimens which are as homogeneous as possible and which are from a lot of material of the type in question. The test specimen should then be randomly assigned in equal numbers to each laboratory for testing. The average results from the two laboratories should be compared using Student's t-test and an acceptable probability level chosen by the two parties before the testing began. If a bias is found, either its cause must be found and corrected or the purchaser and supplier must agree to interpret future test results in the light of the known bias.

The effects of the various reagents used in the chemical methods on the residual fibers in a blend depend upon the history of the fibers and, unless otherwise stated, are generally too small or too uncertain to warrant the application of correction factors.

Fiber composition is generally expressed either on the oven-dry mass of the original sample or the oven-dry mass of the clean fiber after the removal of nonfibrous materials. If nonfibrous materials are not first removed from the textile before the fiber analysis is carried out, or if the treatments described in Section 8 are incapable of removing them, any such materials present will increase the percentage of the fiber constituent with which they are removed during the analysis, assuming they are soluble in the solvent used.

The analytical methods are intended primarily for the separation of binary mixtures of fibers. These procedures may also be used for the analysis of mixtures containing more than two types of fibers by selecting the best combination of methods to use (Table 1). Since a sequence of solvents on a given fiber may produce different results than the expected results from a single solvent, it is advisable to determine the results of such sequential effects when testing multiple fiber blends. It is sometimes more convenient to separate mechanically the yarns in a textile which are of similar types, and then use the appropriate chemical method to analyze each of the components. Table 2 shows the solubilities of the various fibers in different chemical reagents.

TABLE 1 Chemical Methods for Analysis of Fiber Mixtures^A

^A Key to Methods and Reagents:

Method No. 1—80 % acetone(cold)

Method No. 2—N-Butyrolactone

Method No. 3—90 % formic acid

Method No. 4—59.5 % sulfuric acid

Method No. 5—70 % sulfuric acid

Method No. 6—Sodium hypochlorite solution

Method No. 7—Curpammonia solution

Method No. 8—Hot xylene

Method No. 9—90 % formic acid

Method No. 10—N,N-dimethylacetamide

^B Each analytical method is identified by a number and where possible, two methods of analysis are provided for each binary mixture of fibers. The number or numbers inside parentheses refers to the method that dissolves the fiber shown at the top of the diagram. The number or numbers outside the parentheses indicates the method that dissolves the fiber listed at the left side of the diagram. Where two methods are listed for a specific binary mixture, the non-superscript method number represents the method of choice.

TABLE 2 Solubilities of Fibers in Solvents Used in Chemical Methods^A

^A Key to Symbols:

S = Soluble

PS = Partially Soluble

SS = Slightly Soluble (a correction factor may be applied)

I = Insoluble

^B Reworked wools are soluble in 70 % H₂SO ₄ depending upon their previous history.

1. Scope

1.1 These test methods cover procedures for the determination of the fiber blend composition of mixtures of the fibers listed in 1.2. Procedures for quantitative estimation of the amount of moisture and certain nonfibrous materials in textiles are also described, for use in the analysis of mixtures, but these are not the primary methods for the determination of moisture content for commercial weights.

1.2 These test methods cover procedures for the following fiber types:

1.2.1 Natural Fibers:

1.2.1.1 Cellulose-Base Fibers:

Cotton

Hemp

Flax

Ramie

1.2.1.2 Protein-Base Fibers:

Animal hairs (other than wool)

Silk, cultivated

Silk, Tussah

Wool

1.2.2 Man-Made Fibers:

1.2.2.1 Cellulose-Base Fibers:

Acetate (secondary)

Rayon, viscose or cuprammonium

Triacetate

1.2.2.2 Synthetic-Base Fibers:

Acrylic

Aramid

Modacrylic

Nylon 6, Nylon 6-6, others

Olefin

Polyester

Spandex

1.3 These test methods include the following sections and tables:

1.4 The analytical procedures described in the test methods are applicable to the fibers listed in 1.2. The test methods are not satisfactory for the separation of mixtures containing fibers that fall within the same generic class but differ somewhat, either physically or chemically, from each other. These test methods are not satisfactory for the determination of bicomponent fibers.

Note 1—For other methods of analysis covering specific determinations, refer to: Test Methods D 461, Test Method D 584, Methods D 885, Test Method D 1113, Test Method D 1334, and Test Method D 2130. Methods for moisture are covered in Methods D 885, Test Method D 1576, Test Method D 2462, Test Method D 2495 and Test Methods D 2654. For the determination of commercial weight, refer to Test Method D 2494.

1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.

23.1 The following procedures may be used for the quantitative analysis of textiles containing two or more types of fibers that cannot be readily separated chemically. If the sample contains both animal and vegetable fibers, a mechanical separation (Section 10) or a chemical analysis (Sections 11-22) shall first be made. The percentages of the different types of fibers in these two groups shall then be determined by the appropriate method as directed in Sections 24 and 26. The accuracy obtainable with microscopical methods depends to a considerable extent upon the ability of the analyst to identify the different fibers present in the mixture and also upon the number of fibers examined and the number measured.

Note 22—Photomicrographs of common textile fibers are appended to AATCC Method 20.

Index Terms

Acceptance criteria/testing--textile fabrics/fibers; Animal fibers; Bast and leaf fibers/products; Cellulose and cellulose derivatives; Cellulose fiber; Chemical properties--textiles; Composition analysis--textiles; Cotton fibers; Cross-section measurement/properties; Dissection; Extractable matter content--textile fabrics/fibers; Fiber composition; Flax fiber and products; Hemp fibers/products; Man-made textile fibers; Mechanical dissection; Microscopic examination--textiles; Moisture analysis--textile fabrics/fibers; Nonfibrous material; Protein-base fibers; Quantitative analysis/measurement; Ramie; Sampling--textiles; Silk; Synthetic-base fibers; Textile fibers; Textile fibers--bast and leaf; Textile fibers--man-made; Wool and wool top; ICS Number Code 59.080.01 (Textiles in general)

Citing ASTM Standards

[Back to Top]