ACR, a PVC processing aid, has a small dosage but a big effect. Do you know?
In terms of categories, PVC processing aids ACR can be divided into three categories:
1. Processing aids that promote plasticization: This type of processing aid is widely used in rigid PVC products. Its main function is to promote plasticization, improve the rheological properties of the melt and improve the dispersion of other additives, and improve the apparent quality of the product.
Suitable for most PVC products such as profiles, pipes, plates (rolls), etc., reference dosage is 1-2phr
2. Foaming regulator: Due to its high molecular weight, PVC foaming regulator can greatly increase the melt strength of PVC materials, thereby effectively wrapping the foaming gas and forming a uniform honeycomb structure to 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 increasing gloss.
Suitable for foamed sheets, foamed rods, foamed pipes, foamed profiles, foamed wood plastic, etc. The reference dosage is 4-8phr.
3. External lubricating processing aid: It has the same good metal stripping properties as oxidized polyethylene wax. The difference is that it has good compatibility with PVC. To a certain extent, it can also increase the processing plasticizing performance and improve the melt. Rheological properties, and the outlet expansion remains unchanged during extrusion processing, does not change the thermoforming properties, and prevents the haze effect caused by lubricant precipitation in transparent products.
It is suitable for formulas or equipment with high processing requirements, especially transparent sheets, foam profiles, foam boards and foamed wood plastics, etc. Reference dosage 0.5-2phr
Specific to the process and products, the melt elasticity can be improved during calendering, allowing the remaining material to roll smoothly between the two rollers; the apparent quality can be improved during pipe extrusion, eliminating the "shark skin" phenomenon, and increasing the extrusion rate; During transparent extrusion, the number of "fish eyes" in the product can be greatly reduced; during injection molding, the melt elasticity is increased, thereby reducing the injection volume, reducing the "white lines" phenomenon, increasing surface gloss, and improving welding strength. If lubricity is added Processing aids can improve the demoulding efficiency, speed up the injection cycle and increase output, and prevent the "blooming" phenomenon caused by external slippage; during blow molding, they can improve plasticization, reduce fisheye phenomena, improve melt elasticity, and make The molding thickness is more uniform.