How to test the strength and elasticity of acrylic yarn?

Acrylic yarn is a synthetic fiber widely used in the textile industry, favored for its excellent light resistance, weather resistance, softness, and easy dyeing properties. In practical applications, the strength and elasticity of acrylic yarn are important indicators of its performance, directly affecting its effectiveness and lifespan in textile products. Therefore, it is crucial to scientifically and accurately test the strength and elasticity of acrylic yarn. The following is a detailed explanation of the strength and elasticity testing of acrylic yarn.

1、 Testing the Strength of Acrylic Yarn

Strength refers to the ability of a material to resist damage when subjected to external forces. For acrylic yarn, its strength is usually evaluated through tensile testing. The following are the specific testing steps and methods:

1. Testing equipment

Tensile testing machine: used to apply external force and measure the tensile properties of yarn. Common tensile testing machines include electronic universal material testing machines or single yarn strength testers.

Fixture: used to fix both ends of the yarn to ensure that the yarn does not slip during the testing process.

Sensor: used to measure the force and elongation of the yarn during the stretching process.

2. Testing steps

Sample preparation: Randomly select a certain length of sample (usually 50 cm) from the acrylic yarn to ensure that the sample is free of damage and knots.

Fixed sample: Fix both ends of the yarn separately in the fixture of the tensile testing machine, ensuring that the yarn is in a vertical state during the stretching process.

Set parameters: Based on the specifications and testing standards of the yarn, set the stretching speed (usually 500 mm/min) and initial clamping distance (usually 250 mm).

Start testing: Start the tensile testing machine and gradually increase the external force until the yarn breaks.

Record data: During the testing process, the equipment will automatically record the breaking strength (unit: Newton or Gram) and elongation at break (unit:%) of the yarn.

3. Data analysis

Breaking strength: The amount of force a yarn can withstand when it breaks, directly reflecting its strength.

Tensile elongation at break: The ratio of the elongation of a yarn at break to its initial length, reflecting its extensibility.

Strength coefficient of variation: Through multiple tests, calculate the coefficient of variation of yarn strength and evaluate its uniformity.

4. Precautions

The testing environment should maintain a constant temperature and humidity (usually 20 ℃, 65% relative humidity) to avoid the influence of environmental factors on the test results.

Each sample should be tested at least 5 times, and the average value should be taken as the final result.

2、 Testing the elasticity of acrylic yarn

Elasticity refers to the ability of a material to recover its original state after undergoing deformation under external forces. For acrylic yarn, its elasticity is usually evaluated through cyclic tensile testing or elastic recovery rate testing. The following are the specific testing steps and methods:

1. Testing equipment

Cyclic tensile testing machine: used to simulate the performance of yarn during repeated stretching and recovery processes.

Fixture: used to fix both ends of the yarn.

Sensor: used to measure the force and elongation of yarn during stretching and recovery processes.

2. Testing steps

Sample preparation: Similar to strength testing, randomly select a certain length of acrylic yarn sample.

Fixed sample: Fix both ends of the yarn in the fixture of the cyclic tensile testing machine.

Set parameters: According to the testing standards, set the stretching speed (usually 500 mm/min), stretching distance (usually 5% -10% of the initial length of the yarn), and number of cycles (usually 10 times).

Start testing: Start the testing machine and repeatedly stretch and recover the yarn within the set stretching distance.

Record data: During the testing process, the equipment will record the force and elongation of the yarn during each stretching and recovery process.

3. Data analysis

Elastic recovery rate: The ability of a yarn to return to its original state after each stretch, calculated using the formula:

[Elastic recovery rate=frac {length after recovery - initial length} {length after stretching - initial length} times 100%]

Deformation rate: The amount of deformation that a yarn cannot recover after multiple stretches, calculated using the formula:

[Deformation rate=frac {final length - initial length} {initial length} times 100%]

Elastic modulus: The ratio of stress to strain of a yarn within its elastic range, reflecting its ability to resist deformation.

4. Precautions

The testing environment should maintain a constant temperature and humidity to avoid the influence of environmental factors on the test results.

Each sample should be tested at least 3 times, and the average value should be taken as the final result.

3、 Testing standards and specifications

When conducting strength and elasticity tests on acrylic yarn, relevant national standards or industry specifications should be followed to ensure the accuracy and comparability of the test results. Common standards include:

GB/T 3916-2013 "Determination of tensile strength and elongation at break of single yarn in textiles"

GB/T 3923.1-2013 "Textiles - Determination of tensile properties of fabrics - Part 1: Determination of tensile strength and elongation at break"

ISO 2062:2009 "Determination of tensile strength and elongation at break of single yarns in textiles"

4、 Application of Test Results

By testing the strength and elasticity of acrylic yarn, important references can be provided for its application in textile products:

Strength test results: used to evaluate the processability of yarns in the textile process and the durability of their products.

Elasticity test results: used to evaluate the comfort and recovery performance of yarns in clothing, sports equipment, and other fields.

5、 Summary

The strength and elasticity testing of acrylic yarn is an important means of evaluating its performance. Through scientific testing methods and strict operating procedures, key data such as yarn strength, elastic recovery rate, and deformation rate can be accurately obtained, providing reliable basis for the production, processing, and application of acrylic yarn. Meanwhile, the test results also contribute to optimizing the production process of yarn and enhancing its market competitiveness.