APP is atactic polypropylene, called atactic polypropylene in English, which is a by-product of polypropylene production. From the 1970s to the 1980s, domestic and foreign countries began to find ways to comprehensively utilize the by-product APP, and finally made great breakthroughs in asphalt modification, adhesives, rubber and plastic modification, coating products, etc., and APP has become a specialty that has attracted much attention. Chemicals. With the changes in production technology, there are fewer and fewer by-product APPs. Several companies in Europe, the United States and other countries have begun to produce APPs with special processes and have reached a 10,000-ton scale. However, it is called differently in different places, and there are the following names: APP (atactic polypropylene), APAO (amorphous a-olefin copolymer), APOs "amorphous polyolefin", these are actually similar products.