METHOD OF DISSOLVING RRTA IN SULPHURIC ACID USING TWIN SCREW EXTRUDER Russian patent published in 2009 - IPC C08J3/00 

FIELD: chemistry.

SUBSTANCE: method of dissolving RRTA or its copolymers in sulphuric acid using a twin screw extruder, which has transporting, mixing and kneading elements, which include an inlet zone, intermediate zone, mixing zone, reverse transportation zone, degassing zone and pressure raising zone, where the method includes the following steps: moving RRTA or its copolymer to the inlet zone with carrying capacity sufficiently low to prevent sulphuric acid from falling into the inlet zone; feeding sulphuric acid into the inlet zone or intermediate zone; essentially filling the mixing zone to provide for sufficient time for mixing and dissolving RRTA or its copolymer in sulphuric acid, so as to obtain a RRTA solution or its copolymer in sulphuric acid; reverse transformation behind the mixing zone to obtain samples of the product between the mixing zone and the degassing zone; formation of a thin film of RRTA solution or its copolymer in sulphuric acid in the degassing zone in order to degas the solution; feeding the solution into the pressure raising zone at the outlet for partial filling this zone and outlet from the twin screw extruder.

EFFECT: easy dissolution of copolymers in sulphuric acid.

9 cl, 6 dwg, 11 tbl, 10 ex