Pure PVC resin processing easy decomposition, poor liquidity, low impact strength, poor weather resistance, so you need to add in the processing of various auxiliary materials to improve its performance. Such as: lubricants, heat stabilizers, impact modifiers, processing aids.
In the process of the development and application of processing aids, the product components can be broadly divided into the following categories: methyl methacrylate (MMA) / acrylate copolymer, MMA / styrene copolymer, acrylonitrile / styrene, The largest use, the best effect is MMA / acrylate copolymer.
Due to poor performance of pure PVC impact, especially low-temperature impact performance is poor, poor weather resistance, limited applications in many fields. Therefore need to add impact modifier to improve its toughness and weathering performance.
At present, the main types of impact modifiers are chlorinated polyethylene (CPE), impact modifier (MBS) and acrylic impact modifier ACR. Among them, the compatibility of anti-impact ACR and PVC is better than that of CPE and MBS. The transparency of MBS is compatible with other additives, and the impact resistance is better than that of ACR and CPE. However, The price is currently a larger amount in the country. According to statistics, the proportion of global impact modifier consumption is as follows: 45% of MBS, 40% of ACR, and 15% of others.
The domestic ratio: CPE accounted for 65% of the amount of 160,000 tons, MBS accounted for 24% of the amount of 60,000 tons, ACR accounted for 8% of the amount of 20,000 tons, the other accounted for 2% to 5,000 tons.
Impact modifier MBS is MMA grafted styrene butadiene latex after salting out of the core-shell copolymer, with its modified PVC can improve its impact strength and overall performance, because of its similar refractive index with PVC, so that Modified PVC is a good transparency, it is widely used in transparent products. Because it contains butadiene light see the decomposition of aging, it does not apply to outdoor products. MBS was first developed by Rohm and Haas in the 1950s and has now produced 300,000 tonnes, the highest of any type of impact modifier. At present, many manufacturers and brands.