1. What does the shrinkage ratio of heat-shrinkable tubes mean?
In the actual use of heat-shrinkable tubes, one parameter is very important, and that is the shrinkage ratio. So what does the shrinkage ratio mean? ?
Shrinkage ratio, as the name suggests, is the shrinkage ratio of the heat-shrinkable tube. The heat-shrinkable tube will shrink when heated and wrapped on the wrapping. The inner diameter of the heat-shrinkable tube before shrinkage is compared to the inner diameter ratio of the heat-shrinkable tube after complete shrinkage. It's the shrinkage ratio. For example, if the diameter of the heat shrinkable tube is 6mm and the inner diameter is 3mm after complete shrinkage, then the shrinkage ratio is 2:1.
2. How to calculate the shrinkage ratio of heat-shrinkable tubes
The calculation method of the shrinkage ratio of heat-shrinkable tubes is very simple. Measure the inner diameter of the heat-shrinkable tube in the expanded state as R1, and then heat it back Shrink until it is in a fully retracted state. At this time, measure the inner diameter R2. R1:R2 is the shrinkage ratio of the heat shrinkable tube.
However, for double-walled heat shrinkable tubes, after heating and shrinkage, the glue layer flows into an irregular shape, which is not easy to measure. Therefore, there are generally two ways to calculate the shrinkage inner diameter. One method is to only calculate the inner diameter of the sheath layer, and the other method is to calculate the inner diameter of the heat shrink tube during extrusion. It is also because these two methods have errors, so usually the actual shrinkage ratio of double-wall heat shrinkable tubes is slightly larger than the nominal shrinkage ratio in design.
3. Is the bigger the shrinkage ratio of PET heat shrinkable tubes, the better
The common shrinkage ratios of PET heat shrinkable tubes are 2:1, 3:1, and 4:1. The shrink ratio of the shrink tube can reach 6:1, but it should be noted that the larger the shrink ratio of the heat shrink tube, the better.
When choosing a heat shrinkable tube, you should choose a heat shrinkable tube with an appropriate shrinkage ratio based on the specific sample conditions. It does not necessarily mean that a heatshrinkable tube with a larger shrinkage ratio is better, such as When the longitudinal cross-section difference is small, it is more appropriate to choose a heat shrinkable tube with a small shrinkage ratio, which can not only reduce costs, but also improve efficiency and shorten heating time during the heating process.