Before manufacturing any product the first thing in a manufacturer’s mind is its usability and quality of the product – in short customer satisfaction.
Production of spandex is no easy task and to ensure that the quality is maintained is not every body’s cup of tea. So, every person involved in the production of spandex yarn has to be well aware about how the entire process of spandex yarn manufacturing works and how to control it to achieve the required high quality yarn.
Spandex yarn quality is mainly checked by checking the below properties and comparing them to the required standards:
- Tensile properties
- Recovery properties
- Draft ability properties
1. Tensile Properties: Testing of tensile properties need specific equipment with special kind of jaws and specific test method as the elongation % of spandex is very different to any other yarn used in textile application.
Tensile properties cover the following test parameters.
Elongation: It is defined as the “amount of stretch that a fiber can exhibit/withstand” when allowed to stretch under load till break. A good spandex exhibits elongation % between 450-550%.
Tenacity: Tenacity is the test property which measures the relative strength of the yarn. Ratio of breaking force to yarn linear density is denoted as tenacity.
Modulus at 300% elongation: Load required to elongate the yarn up to 300% elongation.
2. Recovery Properties: A good spandex should recover close to its original length once after stretching and releasing the applied load. Specific test method is used to test the elongation recovery after stretching the yarn up to 300% elongation. Minimum of 90% recovery in this test qualifies a spandex for textile application.
3. Draft ability properties: Draft ability properties are tested under dynamic condition. Specific equipment is designed to vary unwinding and winding speed of spandex with different friction points to test the draft ability.