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Usually, during the wearing and application of the fabric, some parts often suffer from a sudden tearing force, such as the part where the clothing is caught by a sharp object, and some parts of the buttocks of the pants are exposed to external forces when squatting. , The internal yarns of the fabric are broken or cracked one by one under load. This phenomenon is called tearing or tearing. Because the tear strength test can objectively reflect the sudden tearing properties of textiles in actual wearing and the degree of influence by finishing, it is widely used in the textile trade. QINSUN is a manufacturer of textile testing instruments. It has been developing and manufacturing various textile testing instruments for more than 10 years. The digital fabric tear tester is a conventional instrument and a widely used test instrument for testing the tear strength of fabrics. The pants method, the pants methode and the shock pendulum method are three commonly used test methods.
Test Standard:
ASTM D1424 D689;NEXT 17;MS P29;BE EN ISO 13937 4674;BS 4468;DIN EN 21974;IOS 3917.1;ISO 1974
>1. Pant Forming Method:
1. Main Principle:
Clamp Pant Form Test Holding the two legs of the specimen so that the notch line of the specimen is a straight line between the upper and lower handles. Start the instrument to apply a pulling force to the direction of the incision, record the tear strength until it is torn to the specified length, and calculate the tear strength according to the peak value on the curve drawn by the automatic drawing device or by an electronic device.
2. Test procedure:
Start the instrument and tear the sample continuously to the end of the sample at a pulling speed of 100 mm/min. Record the tear strength. To obtain the tear trace of the sample, you can use ausing a recording instrument or an electronic recording device to record the tear strength and tear curve of each sample in each direction of fabric. If it comes from the top of a high-density fabric, manual reading should be done, the ratio of the printing paper running speed and the stretching speed should be set to 2:1, and check whether the tearing in the direction of the force applied and whether there is yarn. Threads slide through the fabric instead of tearing. A test is valid if the following conditions are met:
a. The thread has not slipped out of the fabric
b. The preparation has not slipped out of the grip
p> c. Crack* and the crack is in the direction of the applied force
Test results that do not meet the above conditions must be discarded. If the test results of 3 or more samples out of 5 samples are rejected, the method can be considered not applicableon the sample. If it is agreed to increase the number of samples, the number of samples will be doubled and the method of reporting the test results will also be agreed.
2. Trapezoid method:
1. Main principle:
Draw a trapezoid on the sample, and clamp it with the clamp of the strength tester two non-parallel side . Apply a continuously increasing force to the sample so that the crack propagates along the width direction of the sample and determine the average* tear strength.
2. Test procedure:
Set the distance between the two clamps to (25±1)mm, the pulling speed to 100mm/min, select the appropriate load range and make the crack The breaking strength falls between 10%-90% of full scale; install the sample, clamp the sample along the non-parallel sides of the trapezoid, make the incision in the middle of the two clamps, keep the short side of the trapezoid taut, and the long side is in a folded staten.d.; Start the instrument and record the tear strength with an automatic recording instrument if possible. If the tear strength is not along the incision line, do not record it.
3. Swing pendulum method:
1. Main principle:
Fix the sample on the fixture, cut a slit in the sample, let the pendulum into the potential energy position, when the movable armature leaves the fixed armature, the sample is torn along the incision direction, and the work done by tearing a certain length of fabric is converted into tearing force.
2. Test Steps:
Press the pendulum stop button and release the pendulum. Hold the pendulum when it swings back, so as not to change the position of the pointer, read the tear strength from the graduation value of the measuring device or digital display, and the unit is Newton. Depending on the type of instrument used, the reading may need to be multiplied by thecorrect factor from the manufacturer to convert the result to Newtons. Inspection results
See if the tear is in the direction of the force and if the yarn slips out of the fabric instead of tearing. A test is valid if the following conditions are met:
a. The thread has not slipped out of the fabric
b. The preparation has not slipped out of the grip
p> c. Crack* and the crack is always within the width of 15mm
Those who do not meet the above test results should be rejected. If three or more of the five samples are removed, this method becomes invalid. Be applicable.
