COMPOSITION OF CONCENTRATE, METHOD OF ITS PRODUCTION AND METHOD OF INCREASING VISCOSITY OF POLYMERS Russian patent published in 2019 - IPC C08K5/09 C08K5/353 C08G63/91 C08L67/02 C08J11/04 

FIELD: chemistry.

SUBSTANCE: invention relates to an additive concentrate composition which are polymer chain extenders, a method of producing such a concentrate composition and a method of increasing viscosity of polymers, preferably secondary polyester material, for example secondary polyethylene terephthalate (PETP), by using said concentrate composition. Composition of the concentrate for increasing the viscosity of the polymer obtained by polycondensation involves a) a compound selected from dianhydrides of organic acids or combinations thereof, and b) a compound selected from bis- and / or tris- and / or tetrakis-oxazolines or combinations thereof, and c) polymer base. Said components a) and b) are present in quantitative ratio of 5:1 to 1:5 by weight. Composition concentrate is obtained by mixing components a) and b) at rotor rotational rate not less than 1,000 rpm for at least 2 minutes at temperature of not less than 30 °C. Method of increasing viscosity of polymer obtained by polycondensation involves adding polymer material to extruder and subsequent addition of concentrate composition to increase viscosity of polymer. Polymer product is obtained by extruding the mixture using a concentrate composition to increase viscosity. Molded article made from a polymer product is obtained from the obtained polymer product.

EFFECT: invention improves processability of polymers obtained by polycondensation, especially when processing secondary raw materials, improves properties thereof and enables to use such raw material not only for making bottles, but also for forming films, sheets, including foamed materials, as well as for making articles by blow molding.

45 cl, 3 tbl, 46 ex