Exxon Corporation develops α-olefin PP copolymers, which are superior to ethylene/propylene copolymers in terms of performance, can be used as durable packaging film materials, and can also be used for injection molded parts such as automobile bumpers. The crystallization rate of mPP products is slow. The crystallization rate is increased by adding nucleating agents, and the processing is mainly injection molding.

Exxon uses metallocene catalysts on the same support to produce unique isotactic PP homopolymers and copolymers in a single reactor. The copolymers are bimodal (probably the first type of catalyst produced in a single reactor The bimodal resin) can make the copolymer chain in the resin in three ways: isotactic, syndiotactic, and random. The copolymer is more attractive than the homopolymer. When ethylene is added, the initial chain cleavage reaction occurs. In the reverse direction, long chains begin to form again. This new bimodal copolymer can produce good biaxially oriented PP films at lower PP processing temperatures than typical catalyst production.

Reprinted from: "Plastic Industry"