In fact, the thermal properties of insulation materials also determine the thermal properties of the heat shrink tube, because the main material used in the heat shrink tube is the insulation material, the following three aspects of the analysis of the thermal properties of insulation materials.

1. Relationship between life and temperature

Figure 2-19 is a curve of the relationship between life and temperature, from which it can be compared, cross-linked polyethylene materiallife is better than PVC and polyethylene.

2. Overload characteristics

The results of the overload test are shown in Figure 2-20. Under load conditions, changes in the cross-link polyethylene characteristics can only be seen when the temperature is close to 250 degrees C.

3. Anti-aging

The aging test was completed under the hot air condition of 140 degrees C, and the change of tensile strength and extensibility was shown in Figure 2-21.

绝缘材料的热性能

其实绝缘材料的热性能也决定了热缩管的热性能，因为热缩管使用的主要材料就是绝缘材料，下面以3个方面分析了绝缘材料的热性能。

1.寿命和温度之间的关系

图2-19为寿命与温度关系曲线，从图中可以比较出，交联聚乙烯材料的寿命要比聚氯乙烯和聚乙烯好。

2.过载特性

过载试验结果见图2一20。在负载条件下，当温度接近250℃时，才能看见交联聚乙烯特征的变化。

3.抗老化

在140℃的热空气条件下，完成了老化试验，其抗拉强度和伸张度的变化情况如图2一21所示。