THERMOPLASTIC POLYOLEFINS WITH HIGH FLUIDITY AND EXCELLENT SURFACE QUALITY, OBTAINED IN MULTISTEP PROCESS Russian patent published in 2012 - IPC C08L23/12 C08F2/00 C08F210/06 C08F210/16 C08F4/646 C08F4/651 

FIELD: chemistry.

SUBSTANCE: invention provides reactor thermoplastic polyolefins having high fluidity and excellent surface quality, which contain (A) a matrix of a propylene homo- or copolymer whose weight ratio ranges from 40 to 90% with ISO 1133 MFR index (230°C, nominal load of 2.16 kg)≥200 g/10 min, and (B) an elastomeric copolymer of ethylene and propylene whose weight ratio ranges from 2 to 30%, with characteristic viscosity of IV (according to ISO 1628 in decalin as a solvent)≤2.8 dl/g with weight ratio of ethylene ranging from more than 50 to 80% and (C) an elastomeric copolymer of ethylene and propylene whose weight ratio ranges from 8 to 30%, with characteristic viscosity IV (according to ISO 1628 in decalin as a solvent) ranging from 3.0 to 6.5 dl/g and with weight content of propylene ranging from 50 to 80%. The reactor thermoplastic polyolefins are obtained in a process by multistep polymerisation, involving at least 3 successive steps, in the presence of a catalyst comprising (i) a Ziegler-Natta procatalyst which contains a product of transesterification of a lower alcohol and a phthalic ester of complex acids, (ii) an organometallic cocatalyst and (iii) an external donor of formula (I), Si(OCH₂CH₃)₃(NR¹R²), where values of R¹ and R² are given in the claim. The invention also discloses a multistep process of producing said polyolefins, involving either a combination of one loop reactor and two or three gas-phase reactors, or a combination of two loop reactors and two gas-phase reactors, connected in series. Disclosed polyolefins are used to produce articles for the automobile industry by pressure casting. The invention also relates to articles moulded from the reactor thermoplastic polyolefins.

EFFECT: polyolefins can be used for pressure casting large profiles for which no ripple marks appear and which simultaneously demonstrate good balance of impact viscosity, rigidity and high fluidity.

15 cl, 3 tbl, 3 ex