As we all know, severe migration and extraction of plasticizers in PVC will cause major changes in the product, causing the product to soften, sticky, and even surface cracks. The precipitate will often cause product pollution and affect the secondary processing of the product. Therefore, many users want to know how to deal with the migration of PVC plasticizers.
When it comes to this problem, many friends will say that the migration problem will not occur if the plasticizer product is bought. This is not a problem, but many users do not want to increase this additional cost input, so today I will teach you that it can be done without increasing the input cost. Methods to deal with the problem of plasticizer migration:
1. Add polyester plasticizer
Polyester plasticizer has a good affinity with DOP and other small molecule plasticizers. When there is a certain amount of polyester plasticizer in the PVC plasticizer, it can attract and fix other plasticizers from the surface of PVC products. The role of diffusion, thereby reducing and preventing the migration and extraction of plasticizers.
2. Add nanoparticles
Adding nanoparticles can reduce the migration loss rate in soft PVC and improve the performance and life of soft PVC materials. The ability of different nanoparticles to inhibit the migration of plasticizers is different, and the effect of nano-SiO2 is better than nano-CaCO3.
3. Use ionic liquid
Ionic liquids can control the glass transition temperature of polymers in a relatively large temperature range, and the elastic modulus of the materials added is equivalent to that when DOP is used as a plasticizer. Because the ionic liquid has low volatility at high temperatures, its leaching property is low, and its UV stability is good, it is an ideal plasticizer substitute.
4. Surface spray protective coating
Coating a layer of non-migrating substance on the surface of the polymer to reduce the leaching and migration of the plasticizer. The disadvantage of this method is that it may cause a decrease in the flexibility of the material. However, experiments have shown that this coating technology can effectively prevent the plasticizer. The leaching process has broad application prospects in the field of medical PVC.
5. Surface association
In water with a suitable phase transfer catalyst, sodium sulfide is used to modify the surface of the plasticizer. Under the action of light, the surface of the PVC product will form a network structure, which can effectively prevent the migration of the plasticizer. The soft PVC processed in this way is very suitable for applications in medical and related equipment.
6. Surface modification
The leaching of the plasticizer in the polymer from the solution can be controlled by adjusting the properties of the polymer surface. Among many modification techniques, grafting water-soluble polymers on the surface is one of the main directions.
However, if you want to completely solve this phenomenon, knowing how to prevent the migration of PVC plasticizers is the right way. The migration of plasticizers in PVC products is closely related to compatibility. Good plasticizer compatibility means low migration and vice versa.
Therefore, in terms of grasping the compatibility of plasticizers and controlling the migration of plasticizers are important indicators for the safety of plastic packaging materials. At this point, component analysis techniques based on formulation analysis will play a role. The key technical support role.