Plastic anti-theft caps are the common packaging forms for bottle packaging, especially in the beverage field. According to their use, they can be divided into gas-containing beverage caps (abbreviated as gas caps) and non-aerated beverage caps (abbreviated as No gas cap). Polyolefin is generally used as the main raw material, and it is processed by injection molding, hot pressing and other processes. Plastic anti-theft caps are required to facilitate the opening of consumers, but also need to avoid leakage problems caused by poor sealing performance. How to reasonably control the sealing performance of the cap is the focus of the production unit on-line or off-line detection.
First, introduce the standard test method
The national standard GB/T17876-1999 specifically specifies the detection problems of this plastic anti-theft cap, such as the cap open torque, thermal stability, drop resistance, leakage and sealing performance. Among them, the sealing performance and the evaluation of the cap opening and tightening torque are effective ways to solve the sealing performance of plastic anti-theft caps. Depending on the use of the cap, there are different rules for the measurement method without the gas cap and the gas cap. Without gas cap, the cap should be cut to remove the anti-theft ring (strip), used for sealing with a rated torque of not less than 1.2 NM, tested with a sealed tester, pressurized to 200 kPa, kept under pressure for 1 minute under water, and observed for leaks. Gas or tripping; gas cover is pressurized to 690kPa, keep the pressure in water for 1 minute, observe the leak, and then increase the pressure to 1207kPa, keep pressure for 1 minute, observe whether the bottle cap is tripped.
Second, detection applications
This article takes Labthink's "LSSD-01 Leakage and Sealing Strength Tester" as an example. The instrument can be professionally used for quantification of leakage and sealing performance of standard plastic anti-theft bottle caps (gas caps and non-gas caps) with various thread diameters of 28mm and 38mm. It can also be used to seal the bottle caps and bottle caps. The strength of the connection and the sealability, pressure resistance, and burst resistance of the entire bottle were evaluated and analyzed. Equipped with a special "plastic anti-theft bottle cap sealing performance test device", as shown in the figure. The plastic anti-theft caps are packaged with a dedicated connection unit and placed in a transparent observation tank. After the test conditions such as the test pressure or leakage amount are set, the test is started. The instrument automatically performs the test. Test data such as test pressure and leakage can be directly on the LCD. Display on the LCD screen. At the same time, it can also be judged by transparently observing the state of bubbles in the tank.
3, summary
The sealing performance of plastic anti-theft caps is the main factor affecting packaging leakage and product deterioration. Through reasonable control of sealing performance, good opening performance can be ensured and leakage can be avoided. The above is a brief introduction to the detection of leakage and sealing performance of plastic anti-theft caps. It is hoped that this will help the quality control of the production and use of plastic anti-theft caps.