What is BS 5421-2 - Methods of test for polyurethane thread about?
BS 5421 is a series on methods of test for elastomeric threads. Elastomeric threads are polymers with viscoelasticity (i.e., both viscosity and elasticity) and with weak intermolecular forces, generally with low Young's modulus and high failure strain compared with other materials. BS 5421-2 describes eight methods of test for polyurethane thread (elastane yarn):
- method 1 Preparation of test specimens
- method 2 Determination of mass per unit length
- method 3 Determination of breaking load, tenacity, and elongation at break
- method 4 Determination of load at predetermined elongation
- method 5 Determination of stress decay
- method 6 Determination of set
- method 7 Resistance to copper staining during laundering
- method 8 Resistance to atmospheric fume staining
Who is BS 5421-2 - Methods of test for polyurethane thread for?
BS 5421-2 on methods of test for polyurethane thread is useful for:
- Rubber products manufacturers
- Gardening equipment manufacturers
- Design engineers
Why should you use BS 5421-2 - Methods of test for polyurethane thread?
Elastomers are usually thermosets (requiring vulcanization) but may also be thermoplastic (see thermoplastic elastomer). BS 5421-2 describes the method that is intended for threads in the “as received” condition but may be used for treated threads provided that the treatment is specified. Owing to the complexity of the methods existing for accurate determination of thread finish, e.g., infra-red analysis, it is deemed best that information with regard to finish content should be supplied by the thread manufacturer. The value of mass per unit length, determined by the following method, may be used in conjunction with other physical tests provided that the samples or test specimens have not been heated or subjected to other forms of handling that might change their mass per unit length.
BS 5421-2 also defines a method intended to determine the amount of staining caused to adjacent textile materials and the amount of discolouration of a polyurethane thread when it is washed in water containing dissolved copper salts This test has only a comparative value and may not indicate the exact performance of a thread in service because of the wide variation of copper contents of domestic water supplies. BS 5421-2 states a method that is intended to determine the resistance of polyurethane thread to discolouration when exposed to oxides of nitrogen in a test chamber. This effect is also known as gas fume fading. Using BS 5421-2 you can describe eight methods of test for polyurethane thread (elastane yarn).