PVC plastic doors and windows have been widely used due to their excellent insulation, noise reduction, sealing and other characteristics. Especially in the cold regions of northern China and areas prone to sandstorms, it fully demonstrates its unparalleled superiority. However, PVC plastic windows have also exposed certain weaknesses after years of use, such as poor low-temperature impact resistance, cracking, aging and discoloration.

Since the 1980s, the production capacity of CPE in China has been strong, with a large output and a trend of oversupply. Therefore, it is very common for domestic enterprises producing PVC window profiles to use CPE as an impact modifier. After the 1990s, with the increase of acrylic acid ester (ACR) production in China, the cost decreased, which led to more PVC window profiles being adopted by manufacturers. The superiority of ACR has increasingly demonstrated its significant effect in improving the low-temperature impact resistance of PVC, reducing cracking, and improving aging and discoloration issues. At present, the main impact modifier used abroad, especially in Europe, is ACR, which has significantly better performance than products such as CPE as modifiers. Therefore, the application of ACR is an important way to improve the performance of PVC plastic windows.

The selection of impact modifiers should pay attention to the following aspects: firstly, the compatibility with PVC resin should be moderate. If the compatibility is too large, the two types are completely mixed at the molecular level. Impact modifiers may act as plasticizers, closely adhering to PVC molecules, and causing the impact force to directly act on the PVC chain, without improving impact resistance. On the contrary, if the compatibility between the two is too small to achieve uniform dispersion, the adhesion to PVC is lost, and the impact force cannot be absorbed. Secondly, the glass transition temperature should be low, which can enhance the impact resistance of PVC at low temperatures. Once again, the molecular weight should be high, and if necessary, mild crosslinking is recommended to improve the reinforcement effect. Secondly, it has no significant impact on the performance and physical properties of PVC. Once again, the weather resistance should be good and the mold expansion should be small. Finally, blending with PVC has good processability and good heat resistance (deformation resistance, thermal stability). No modifier is perfect, so when choosing it, in addition to paying attention to the above aspects, it is also important to consider its main functions.