The methods to determine the heat sealing strength of plastic packaging bags are:
1. Make a sample. Take any samples on the side, back, top or bottom of the plastic film packaging bag, perpendicular to the heat-sealing part, and use them as heat-sealing samples on the side, back, top or bottom of the packaging bag (10 samples are cut for each part , At least from 5 plastic film packaging bags). The sample width is (15±0.1) mm, and the unfolded length is (1000±1) mm. However, when the sample with an unfolded length of (100 ± 1) mm cannot be obtained, use cellophane adhesive tape to bond the same material as the bag so that the unfolded length of the sample is (100 ± 1) mm.
2. Status adjustment. The sample should be adjusted for at least 4h in the following environment. The temperature is (23±2)℃, and the relative humidity is normal humidity.
3. Sample step. Take the sealed part as the center line of the sample after state adjustment, unfold it to 180°, clamp the two ends of the sample on the two clamps of the testing machine (XLW intelligent electronic tensile testing machine), and make the sample The longitudinal axis coincides with the center line of the upper and lower clamps, and should be tight enough to prevent the sample from slipping and breaking in the clamp. Adjust the distance between the clamps, set the test speed to (300±20) mm/min, start the test, and automatically judge the force value. When Fn+1>Fn, register the Fn+1 value; when Fn+1≤70%Fn, judge Downtime.
During the test, if the test sample is broken in the fixture, the secondary sample is invalid, and another sample is taken to make a replacement. At the end of the seal, the material itself breaks. In this case, when the seal strength is greater than the breaking force of the plastic film, the production process should be considered.