HIGH-PURITY HETEROPHASE PROPYLENE COPOLYMERS Russian patent published in 2012 - IPC C08F4/646 C08F4/651 C08F2/00 C08F210/06 C08L23/12 

FIELD: chemistry.

SUBSTANCE: invention relates to a catalyst system, production and use of high-purity heterophase propylene copolymers which contain (A) a matrix of a propylene homo- or copolymer whose weight ratio ranges from 73 to 98%, with ISO 1133 MFR₂ index ≥45 g/10 min and (B) an elastomeric copolymer whose weight ratio ranges from 2 to 27%, wherein the weight ratio of propylene is at least 50% of component (B) and weight ratio of ethylene and/or any other C₄-C₁₀ alpha-olefin is at least 50% of component (B). Propylene copolymers are obtained during multi-step polymerisation in the presence of the catalyst system, including (i) a Ziegler-Natta procatalyst which contains a product of transesterificatin of a lower alcohol and a phthalic ester of complex acids, and (ii) possibly an organometallic cocatalyst, and (iii) an external donor of formula (I) Si(OCH₂CH₃)₃(NR¹R²), where elements R¹ and R² can be the same or different hydrocarbon groups, each containing 1-12 carbon atoms. The copolymers are used to produce moulded articles.

EFFECT: obtained polymers have high MFR index, low content of oligomers, high purity and low misting.

16 cl, 1 tbl, 8 ex