METHOD OF PRODUCING MULTIMODAL COATING COMPOSITION Russian patent published in 2020 - IPC C08F10/02 C08F210/16 C08L23/04 C09D123/04 C09D123/08 F16L58/10 

FIELD: chemistry; technological processes.

SUBSTANCE: invention relates to production of coated metal pipe. Method includes the homopolymerization of ethylene or copolymerization of ethylene and α-olefin comonomer in the first polymerization stage in the presence of a polymerization catalyst to obtain a first ethylene homo- or copolymer with density of 940–980 kg/m³ and a melt flow rate MFR₂ 1–2000 g/10 min. Homopolymerization of ethylene or copolymerisation of ethylene and α-olefin comonomer is carried out at the second stage of polymerisation in the presence of the first homo- or copolymer of ethylene to obtain a first mixture of an ethylene polymer containing a first homo- or copolymer of ethylene and a second homo- or copolymer of ethylene. First mixture of ethylene polymer has density of 940–980 kg/m³ and a melt flow rate MFR₂ of 10–2000 g/10 min. At the third step, ethylene and α-olefin comonomer are copolymerised in the presence of a first ethylene polymer mixture to obtain a second ethylene polymer mixture containing a first ethylene polymer mixture and a third ethylene copolymer. Second mixture of ethylene polymer has density of 915–965 kg/m³ and a melt flow rate MFR₅ of 0.2–10 g/10 min. Pipe with outer surface layer is produced. Coating composition is applied on layer of pipe outer surface to produce top coating layer, where coating composition contains second mixture of ethylene polymer.

EFFECT: obtaining coatings with improved adhesion and mechanical properties, which can be applied at high speed.

13 cl, 2 tbl, 10 ex