METHOD OF PRODUCING AQUEOUS DISPERSION OF POLYTETRAFLUOROETHYLENE Russian patent published in 2024 - IPC C08F14/26 C08F114/26 C08F2/22 C08F2/44 C08F265/06 C08F283/06 C08L51/00 C08L51/08 

FIELD: chemistry.

SUBSTANCE: present invention relates to methods of producing an aqueous dispersion of polytetrafluoroethylene. Method of producing an aqueous dispersion of polytetrafluoroethylene involves: step A1 of non-fluorinated monomer polymerisation in an aqueous medium to obtain solution 1 containing a polymer containing links based on said non-fluorinated monomer; step A2 of polymerising tetrafluoroethylene in said solution 1 substantially without adding a surfactant to said solution 1 to obtain an aqueous emulsion containing polytetrafluoroethylene particles; and step A3 of adding a non-ionic surfactant to said aqueous emulsion and then concentrating said aqueous emulsion to obtain an aqueous dispersion of polytetrafluoroethylene. Amount of said non-fluorinated monomer used is at most 200 ppmw relative to the amount of said tetrafluoroethylene fed into the polymerisation system. Content of the non-ionic surfactant in the aqueous dispersion of polytetrafluoroethylene ranges from 1 to 20 wt.%. relative to the weight of polytetrafluoroethylene.

EFFECT: said method leads to the fact that the formation of fluorinated oligomers as by-products is small, and the critical thickness of cracking (CFT) of the coating film to be obtained is large.

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