DIN 53842-1 Textile Tests - Knot Pull Test for Single and Multi-Ply Yarns

The standard “DIN 53842-1 Textile tests - Knot pull test for single and multi-ply yarns”, published by the German Institute for Standardization (DIN), describes the procedure for knot pull tests on single and multi-ply yarns. This standard is used as a reference and remains valid in many textile testing laboratories and equipment specifications worldwide, especially in European countries.

The knot pull test determines the maximum tensile strength (breaking strength) of a yarn when a knot is tied in the test section. This test evaluates how the yarn performs under tension when weakened by the knot. This is a common scenario in textile processing, weaving, knitting, sewing, or end-use applications where yarns may contain knots or loops.

This method is particularly useful in evaluating the following aspects:

• Weakness caused by yarn quality and knotting.
• Suitable for high-tension applications (e.g., sewing threads, industrial threads)
• Comparison with standard flat tensile tests (e.g., DIN EN ISO 2062 standard)

The relevant standard, “DIN 53843-1 Textile tests - Loop tensile test - Yarns”, covers the loop tensile test for yarns, while the standard “DIN 53842-2 Textile tests - Knot tensile test of knitting yarns for fishing nets” specifically addresses the knot tensile test for netting yarns used in fishing nets.

The basic aspects of the DIN 53842-1 standard test method are as follows:

• A knot is tied within the free measurement length of the yarn sample.
• The sample is then subjected to a tensile load (usually on a constant elongation rate testing machine) until it breaks.
• The test measures the maximum tensile force at the moment of rupture.
• This method is applicable to both single yarns and twisted (crimped) yarns.

This method helps determine the nodal strength, which is generally lower than the straight-line rupture strength due to bending and compressive stresses at the nodal point.

Laboratories typically perform this test on conditioned samples (standard atmosphere for textiles) and report the results, along with linear density to calculate toughness if necessary.

Textile testing laboratories, yarn manufacturers, and machinery manufacturers routinely use the DIN 53842-1 standard along with other yarn tests such as the following:

• Single end breaking strength and elongation (DIN EN ISO 2062 standard)
• Loop pull test (DIN 53843-1 standard)
• Twist determination (DIN EN ISO 2061 standard)
• Linear density (DIN EN ISO 2060 standard)

This standard is included in the service manuals of testing institutes and university laboratories, as well as in equipment brochures from some manufacturers.

In short, the DIN 53842-1 standard outlines a methodology for testing textiles, particularly determining the elastic behavior of fabrics under tensile loads. This standard is widely used in textile engineering, quality control, and research laboratories.

The DIN 53842-1 standard defines a method specifically for measuring the elastic properties of textile materials:

• Elastic elongation (how much a fabric stretches under force)
• The behavior of returning to its original state (how well it returns to its original shape)
• Permanent deformation (elongation remaining after the load is removed)

This standard applies in particular to:

• knitted fabrics
• Elastic woven materials
• Technical textiles (e.g., sportswear, medical textiles)

The described method involves subjecting a fabric sample to a controlled tensile force and observing its behavior over time. The method generally follows these steps:

• Sample preparation: Samples are cut to defined dimensions. Samples are conditioned under standard temperature and humidity.
• Loading phase: A specified force is applied gradually. The resulting elongation is measured.
• Holding phase: The force is maintained for a defined period of time.
• Release phase: The force is removed, and recovery is measured after a defined relaxation period.

The main parameters measured using this method are as follows:

• Total elongation percentage
• Elastic elongation percentage
• Percentage of plastic (permanent) elongation
• Recovery percentage

These values ​​help determine how a fabric behaves under repeated use or stress.

The necessary equipment used in the tests includes:

• Tensile testing machine (constant elongation rate)
• Suitable holders for textile samples.
• Measuring scale or extensometer
• Environmental conditioning room (optional but recommended)

The DIN 53842-1 standard is widely used in the following areas:

• Clothing industry (e.g., sportswear, underwear, stretch fabrics)
• Medical textiles (e.g., compression bandages, elastic supports)
• Automotive textiles (e.g., seat covers, interior fabrics)
• Technical and industrial textiles

The importance of the DIN 53842-1 standard stems from its ability to ensure that textile materials with elastic properties perform reliably, consistently, and safely in real-world applications. Without such a standard, stretch and recovery assessments would vary greatly among manufacturers, leading to inconsistent product quality. This standard is considered important for the following reasons:

• It ensures consistent quality: Elastic fabrics must behave predictably. This standard provides a uniform testing method so that manufacturers can:
  • To produce fabrics with consistent stretch behavior.
  • Maintaining consistent quality across different production batches.
  • Comparing results between suppliers and laboratories.
• Supports functional performance: Many textile products rely directly on elasticity for their function.
  • Sportswear requires flexibility and shape retention.
  • Medical textiles should apply controlled pressure (e.g., compression bandages).
  • Underwear and socks require comfort and support.

This standard ensures that fabrics stretch sufficiently while also recovering properly, preventing sagging or deformation.

• Increases durability and lifespan: Repeated stretching can damage fabrics over time. This standard helps to assess the following:
  • Resistance to permanent deformation.
  • Ability to return to its original state after repeated use.
• It ensures fair comparison and trade: In global textile markets,
  • Buyers need objective data to compare products.
  • Suppliers must meet the agreed performance criteria.

This standard facilitates the following by creating a common technical language:

• Materials approval
• Conflict prevention
• Ensuring compliance with specifications.

In conclusion, the DIN 53842-1 standard is a critical standard for evaluating the elastic performance of textile materials. By defining a consistent and repeatable test method, it helps industries ensure that fabrics not only stretch effectively but also retain their shape and functionality over time.

For many years, our organization, with its competent and experienced staff, has been understanding the needs of its clients, providing the advanced testing services they require, and assisting them in the establishment, implementation, and improvement of management systems. Within this framework, we also provide testing services in accordance with the DIN 53842-1 standard.