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AssigneeHoechst Aktiengesellschaft
InventorsKarlheinz Stahl, Wolfgang Neumann, Hubert Seitz
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Concentrated, aqueous, colloidal dispersions of tetrafluoroethylene polymers having a polymer solids content of 25 to 70% by weight, which comprise, as the dispersion stabilizer, an amine oxide of the formula ##STR1## in which R.sup.1 is an alkyl radical having 6 to 22 carbon atoms or a mixture of such alkyl radicals and R.sup.2 is an alkyl radical having 1 to 22 carbon atoms or a mixture of such alkyl radicals, and in which R.sup.1 and R.sup.2 are identical or different and 50 to 0% by weight of the alkyl radicals R.sup.1 and R.sup.2 can be replaced by alkenyl radicals having 6 to 22 carbon atoms and having 1 to 3 C.dbd.C double bonds, are obtained by concentration with addition of these dispersion stabilizers. The dispersions are used for impregnating yarns and textile sheet-like structures.
A concentrated aqueous, colloidal dispersion, comprising 25 to 70% by weight, based on the total weight of the aqueous dispersion, of a tetrafluoroethylene polymer and 0.5 to 15% by weight, based on the polymer solid, of an amine oxide of the formula ##STR5## in which R.sup.1 is alkyl having 6 to 22 carbon atoms or a mixture of such alkyls and R.sup.2 is alkyl having 1 to 22 carbon atoms or a mixture of such alkyls, and in which 50 to 0% by weight of the alkyls R.sup.1 and R.sup.2 are optionally replaced by alkenyl having 6 to 20 carbon atoms and having 1 to 3 C.dbd.C double bonds.
A process for the preparation of a concentrated, colloidal, aqueous dispersion of a tetrafluoroethylene polymer, which comprises adding an amine oxide of the formula ##STR6## in which R.sup.1 is alkyl having 6 to 22 carbon atoms or a mixture of such alkyls and R.sup.2 is alkyl having to 22 carbon atoms or a mixture of such alkyls, and 50 to 0% by weight of the alkyls R.sup.1 and R.sup.2 are optionally replaced by alkenyl having 6 to 22 carbon atoms and having 1 to 3 C.dbd.C double bonds, as the dispersion stabilizer to an aqueous, colloidal dispersion of the same polymer having a lower polymer solids content and concentrating the dispersion to a polymer solids content of 25 to 70% by weight.
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