METHOD FOR CONCENTRATING AQUEOUS DISPERSION OF COPOLYMER TETRAFLUOROETHYLENE WITH HEXAFLUOROPROPYLENE Russian patent published in 2005 - IPC

FIELD: organic chemistry, chemical technology, polymers.

SUBSTANCE: invention relates to a method for concentrating an aqueous dispersion of copolymer tetrafluoroethylene with hexafluoropropylene. Method involves thermal settling, mixing the parent dispersion with non-ionogenic surface-active substance as a stabilizing agent, heating the mixture if necessary, its keeping without stirring and the following cooling by natural way if necessary, separation of the concentrated phase from upper layer, diluting the concentrated phase up to the content of copolymer 50-55 wt.-% if necessary. Method involves using neonol AF-9-n as a non-ionogenic surface-active substance representing a mixture of polyethylene glycol esters of monoalkylphenols of the formula: R-C₆H₄O-(CH₂CH₂O)_nH wherein R means isononyl as radical -C₉H₁₉ joined to phenol at para-position with respect to hydroxyl group; n means average number of ethylene oxide moles joined to one mole of alkylphenols = 9-10. Indicated neonol is added in the amount 7-10% of water mass in the parent dispersion. Mixture is heated to temperature 55°C, not above, kept its without stirring up to complete separation of phases. Cooling is carried out up to temperature 20-40°C and separation of the concentrated phase from upper layer is carried out at indicated temperature. Invention provides reducing time required for separation of phases.

EFFECT: improved method for concentrating.

7 cl, 1 tbl, 26 ex