When I first came into contact with this line, I heard that my predecessors often said: Our products are "industrial MSG", the amount of use is small, but the effect can not be underestimated. The performance quality of PVC products is directly related to it. Later, it was found that many times including the industry. People have more or less misunderstanding about the classification and function of ACR. They have carefully combed the understanding of PVC processing aids in these years, hoping to help friends to improve their understanding!
From a large category, PVC processing aids ACR can be divided into three broad categories:
1. Promote plasticizing processing aids: This type is widely used in hard PVC products. Its main function is to promote plasticization, improve melt rheological properties and improve the dispersibility of other additives, and improve the apparent quality of products.
Applicable to most PVC products such as profiles, pipes, plates (rolls), reference dosage 1-2phr
2. Foaming regulator: PVC foaming regulator can greatly increase the melt strength of PVC material due to its high molecular weight, thus effectively encapsulating the foaming gas to form a uniform honeycomb structure and prevent gas from escaping. PVC foaming regulator is also beneficial to the dispersion of other additives including foaming agents, improving the surface quality of products and improving gloss.
Applicable to foamed sheet, foamed rod, foamed tube, foamed profile, foamed wood and plastic, etc., reference dosage 4-8phr
3. External lubrication type processing aid: It has the same good metal stripping property as oxidized polyethylene wax. The difference is that it has good compatibility with PVC, and can also increase processing plasticizing performance and improve melt to a certain extent. Rheological properties, and the outlet expansion does not change during extrusion processing, does not change the thermoforming performance, and prevents the haze effect caused by the precipitation of the slip agent in the transparent article.
It is suitable for formulas or equipment with high processing requirements, especially transparent sheets, foamed profiles, foamed sheets and foamed wood plastics. Reference dosage 0.5-2phr
Specifically, in the process and the product, the melt elasticity can be improved during the calendering process, and the residual material between the two rolls can be smoothly rolled; the apparent quality can be improved in the pipe extrusion, the "shark skin" phenomenon can be eliminated, and the extrusion rate can be improved; Transparent extrusion can greatly reduce the number of "fish eyes" in the product; increase the melt elasticity in injection molding, thereby reducing the amount of injection, reducing the "white grain" phenomenon, improving the surface gloss, improving the welding strength, if adding lubricity Processing aids can improve the efficiency of film removal, speed up the injection cycle and increase the yield, and prevent the phenomenon of “blooming” caused by the external slippage. In the blow molding, the plasticization can be improved, the fisheye phenomenon can be reduced, and the melt elasticity can be improved. The forming thickness is more uniform.