Plastic packaging printing and compounding technology Q & A (3)

22. What are the testing methods for bags made of composite materials?
Test methods for packaging bags made of composite materials: 1 Appearance visual inspection: Visual inspection of the surface of the composite bag for signs of scratches and pinholes. Focus on checking whether there is any contamination in the seals. If one of the above conditions is a nonconforming product. 2 Sealing Adhesion Inspection: Sealing some small seams can not be immediately determined by visual inspection. A slight oversight is the cause of leakage and corruption in the future. Check that the seal can be sprayed on the seal with a dye-added surface active agent to determine whether the seal is tight or not. 3 Sealing strength test: Sealing of the compound bag to be inspected, cutting a strip with a width of 15 mm, and measuring the sealing strength with a universal material measuring instrument at a speed of 300±20 mm/min, the general composite bag sealing strength should reach 23 to 34 N/ 15mm. Various types of bag seal strength standards can be found in the following table.
4 Leak test: Saturation solution; usually used to test leaks or pinholes in composite bags with minimal air content. The method is to add the surfactant into the bag, seal the bag and lay it on the filter paper, and after 5 minutes see if there is color liquid on the filter paper, then reverse the bag and test again. Water pressure method. Check whether the air bag with more air content leaks. The method is to put the composite bag to be tested into a device, turn on the vacuum pump, depressurize the glass bottle to 1333 Pa (10 mmHg) within 30 seconds to 1 minute, and maintain it for 30 seconds. Bubble overflows.
5 Compressive strength test: Place the composite bag horizontally on the platform, add a heavy weight to the platform, hold it for one minute, remove and inspect the seal, and see if there is any leakage in the appearance. The flat mouth compound bag and the box compound bag have slightly different pressurization methods. The pressurization time is 1 minute. The pressurization weight differs depending on the weight of the product (standards are shown in the table below).
Various weight pressure standards
6 burst strength test: In a gap between two parallel plates 1.27cm (0.51n), place the composite bag to be tested, install a holder and rubber tube on the bag, in 10 to 30 seconds through the tube Slowly pass the compressed air into the bag and allow the internal pressure to reach the predetermined standard for another 30 seconds. The breaking strength of general commercial bags should reach 0.1 MPa or more.
7 Drop test: Composite bagged products were dropped horizontally and vertically on a rough concrete floor, one at a time. After dropping, check whether the compound bag has caused bag leakage or perforation. The drop height is based on the size of the composite bagged product. The weight varies (see the table below).
Drop height standard
8 bags of air inventory test: Destructive test: Using the principle of drainage and steam collection method, under the surface of the water will cut a bag of notch, the funnel is inverted above the collection of this gap floating on the gas, then add a funnel The amount of water that is filled is simple, and the amount of gas that is filled in the measuring cylinder can finally be used to know the amount of air remaining in the bag (this method is not easy for the gas to be completely discharged, which may cause errors for certain products with high viscosity). Non-destructive inspection: It is determined by using the principle that a buoyancy force of a composite bag containing air is exactly equal to its weight under a liquid surface pressure and is suspended. The samples tested were not destroyed and could be used again. The method is as follows: Put the test composite bag into a transparent container full of water and slowly pull the vacuum. The vacuum degree when the bag is suspended is called the neutralization point.
23. What are the types of plastic film sealing machines (including plastic composite materials)?
There are many kinds of sealing bag making machines used for plastic film packaging bags, such as single-use flat-bottomed or round-bottomed, used for sealing on both sides or three sides, and used for making vest bags, etc.
(1) The introduction of electronic chase color flat bottom and back type sealing bag machine. It is used to make LDPE, HDFE, LLDPE, PP, OPP, PVC, and other films. After the printing process, the heat sealing and cutting are completed once. The maximum output per minute is 110. There are 2211 to 4011 models available, which can heat seal 0.015 to 0.18mm thick film. The machine adopts photoelectric control, accurate sealing and cutting position, neat cutting, close structure, and low power consumption. If used in conjunction with a satellite gravure web press, a relatively complete production line can be formed.
(2) Japan West Machinery Co., Ltd. SBM-500-FE high-speed automatic bag making machine is used for self-supporting bags and three-side sealing bags for automatic assembly machines. It is suitable for combination gravure printing machine and compound machine.
Main technical specifications:
The minimum amplitude is 50m/m to the maximum amplitude is 250m/m;
(1) The minimum annual size of this process is 50m/m to 400m/m.
(2) Bag making speed: 50 to 100 segments per minute (from China Packaging News)