1. Test standards and basic data for elastic recovery
The elastic recovery of PVC Seal is usually determined by a specific test method. Generally speaking, the industry often uses tensile tests to measure it. The PVC Seal is made into a standard specimen, stretched at a specified stretching speed, and maintained for a period of time after reaching a certain elongation. Then the external force is removed to observe its recovery. For example, under common test standards, when the PVC Seal is stretched to 100% of its original length, maintained for 5 minutes, and then the external force is released, the quantitative index of its elastic recovery can be expressed by the recovery rate. Generally, the recovery rate of high-quality PVC Seal under such conditions can reach about 90%-95%. This basic data reflects the self-recovery ability of PVC Seal under conventional deformation, but the elastic recovery ability in actual application is also affected by many factors.
2. Internal factors affecting elastic recovery
The elastic recovery ability of PVC Seal is closely related to its internal molecular structure and formula. The degree of polymerization of PVC resin itself has an important influence on elasticity, and a higher degree of polymerization often provides a better elastic foundation. In addition, the plasticizer in the formula is one of the key factors affecting elasticity. High-quality plasticizers can weaken the interaction between PVC molecular chains, increase the flexibility and mobility of molecular chains, and thus improve elastic recovery. For example, when dioctyl phthalate (DOP) is used as a plasticizer, within the appropriate addition range, PVC Seal can maintain good elasticity during multiple stretching and retraction. At the same time, the type and amount of stabilizers and fillers will also affect the elastic recovery. Inappropriate stabilizers may cause the PVC molecular chains to degrade during processing or use, reducing elasticity, while excessive fillers may hinder the movement of molecular chains and affect elastic recovery.
3. The role of external factors on elastic recovery
In addition to internal factors, the external environment and use conditions also have a significant impact on the elastic recovery of PVC Seal. Temperature is a key external factor. At higher temperatures, the activity of PVC molecular chains is enhanced, and the elastic recovery ability will be relatively improved, but if the temperature is too high, it may cause the material to soften and deform, or even lose elasticity. On the contrary, in a low temperature environment, the activity of the molecular chain is restricted, the PVC Seal will become hard and brittle, and the elastic recovery ability will be greatly reduced. For example, in an environment of -20℃, the elastic recovery of PVC Seal may be only 30%-50% of that at room temperature. In addition, the number of long-term compression or stretching cycles will also affect the elastic recovery. Frequent deformation will cause fatigue of the molecular chain, resulting in a gradual decrease in elasticity. For example, in the application scenario where doors and windows are frequently opened and closed, the elastic recovery of PVC Seal will gradually decrease after thousands of stretching and compression.
4. The significance of elastic recovery in practical applications
The elastic recovery of PVC Seal is crucial in practical applications. In the application of door and window sealing, good elastic recovery can ensure that the sealing strip can still fit tightly after the doors and windows are opened and closed many times, effectively blocking the penetration of air and moisture. If the elastic recovery is insufficient, the sealing effect of doors and windows will gradually deteriorate over time and with the increase in the number of uses, resulting in increased energy consumption, such as the energy consumption of heating or air conditioning. In the automotive industry, the elastic recovery of PVC Seal plays a key role in maintaining a quiet environment in the car and preventing dust and rain from entering the car. Therefore, accurately understanding and controlling the elastic recovery ability of PVC Seal is of great significance for optimizing product quality and improving sealing effect.
