Handheld paper bags are generally made of high-quality and high-grade paper, kraft paper, coated white cardboard, copperplate paper, white cardboard, etc. They are simple, convenient, and have good printability with exquisite patterns. They are widely used in the packaging of goods such as clothing, food, shoes, gifts, tobacco and alcohol, and pharmaceuticals. During the use of tote bags, there is often a problem of cracking at the bottom or side seals of the bag, which seriously affects the service life of the paper bag and the weight and quantity of the items it can hold. The phenomenon of cracking in the sealing of hand-held paper bags is mainly related to the adhesive strength of the sealing. It is particularly important to determine the adhesive strength of the sealing of hand-held paper bags through testing technology.
The sealing adhesive strength of hand-held paper bags is specifically specified in QB/T 4379-2012, requiring a sealing adhesive strength of not less than 2.50KN/m. The sealing adhesive strength shall be determined by the constant speed tensile method in GB/T 12914. Take two sample bags and test 5 samples from each bag's lower end and side. When sampling, it is advisable to place the bonding area in the middle of the sample. When the sealing is continuous and the material breaks, the sealing strength is expressed as the tensile strength of the material at the time of fracture. Calculate the arithmetic mean of 5 samples at the low end and 5 samples at the side, and take the lower of the two as the test result.
Adhesive strength is the force required to break a seal of a certain width. This instrument adopts a vertical structure, and the clamping fixture for the sample is fixed with a lower clamp. The upper clamp is movable and connected to a force value sensor. During the experiment, the two free ends of the sample are clamped in the upper and lower clamps, and the sample is peeled off or stretched at a certain speed. The force sensor records the force value in real time to obtain the adhesive strength of the sample.
1. Sampling
Take two sample bags and test 5 samples from each bag's lower end and side. The sampling width should be 15 ± 0.1mm and the length should be at least 250mm. When sampling, it is advisable to place the adhesive in the middle of the sample.
2. Set parameters
(1) Set the testing speed to 20 ± 5mm/min; (2) Set the sample width to 15mm; (3) The spacing between the clamps is set to 180mm.
3. Place the sample
Take one of the samples and clamp both ends of the sample between the upper and lower clamps. Each clamp should firmly clamp the full width of the sample along a straight line without damage or sliding.
4. Testing
Press the 'reset' button to reset before testing. Press the "Test" button to start the test. The instrument displays the force value in real time. After the test is completed, the upper clamp is reset and the screen displays the test results of the adhesive strength. Repeat steps 3 and 4 until all 5 samples have been tested. Press the "Statistics" button to display the statistical results, which include the average, maximum, minimum, standard deviation, and coefficient of variation of the adhesive strength.
5. Experimental results
Calculate the arithmetic mean of 5 samples at the low end and 5 samples at the side, and take the lower of the two as the test result.
Conclusion: The adhesive strength of the seal of a hand-held paper bag is an important factor that determines whether it is prone to cracking during use. To a certain extent, it determines the weight, quantity, and service life of the product that the hand-held paper bag can withstand, so it must be taken seriously.
Post time: Jul-31-2024