DIN EN ISO 3071 Textiles: pH value (accredited)

Our test laboratory performs testing according to DIN EN ISO 3071 using an accredited test method to determine the pH value of the aqueous extract of textiles. The method is suitable for a wide range of textile materials, including fibres, yarns, woven fabrics, knitted fabrics and other textile structures. The pH value determined indicates whether components extracted from the textile exhibit an overall acidic, neutral or alkaline reaction. The test therefore provides important information on the chemical condition of a textile material and on possible influences resulting from manufacturing, processing and finishing.

Test procedure

For the test, two representative test specimens of approximately 2 g each are taken and cut into small pieces. Each specimen is treated with a defined potassium chloride solution and mechanically shaken for two hours at room temperature. During this process, water-soluble and other acidic or alkaline components extractable under the specified conditions are transferred into the solution.

The pH value of both extracts is then determined electrometrically using a calibrated pH meter with a glass electrode. The mean value is calculated from two sufficiently consistent measurements. If the difference between the individual results is too large, the test is repeated using additional test specimens.

Applications of the standard

Testing according to DIN EN ISO 3071 is used both for the quality control of textile raw materials and semi-finished products and for the assessment of finished textile products. An unusual pH value may, for example, indicate influences or residues resulting from washing, dyeing, bleaching, finishing or other textile-chemical processing steps. The test is therefore suitable for applications including incoming goods inspection, production monitoring, supplier assessment, product development and comparative material investigations.

Typical test materials and applications include:

• fibres and textile raw materials,

• yarns and twisted yarns,

• woven and knitted fabrics,

• textiles used in clothing and footwear,

• upholstery and furniture covering fabrics,

• textile materials used in vehicle interiors, for example seat covers, trim materials and headliners,

• technical textiles and materials for personal protective equipment,

• textiles used in consumer products and toys,

• textile components of composite materials.

The test is particularly important for products for which requirements concerning the permissible acidic or alkaline reaction of the material have been specified. The pH value does not describe the concentration of a single chemical substance, but rather the overall effect of the components extracted under the defined test conditions. The method is therefore particularly suitable as a control procedure for assessing the condition of a textile material after manufacturing and chemical treatment.

Related tests

As a related test, FILK also offers DIN EN ISO 4045 for determining the pH value and difference figure of leather. For protective gloves, DIN EN ISO 21420 is also relevant, as it includes requirements relating to the pH value of the materials used. In addition, DIN 54275 provides another method for determining the pH value of textile fibre materials, using an extrapolation procedure. Depending on the material and application, different standardized methods are therefore available for assessing the pH value.