초록 ▼

The present invention provides an aqueous non-melt processible polytetrafluoroethylene dispersion comprising non-melt processible polytetrafluoroethylene particles in an amount between 30 and 70% by weight based on the total weight of the dispersion and one or more non-ionic surfactants and wherein

The present invention provides an aqueous non-melt processible polytetrafluoroethylene dispersion comprising non-melt processible polytetrafluoroethylene particles in an amount between 30 and 70% by weight based on the total weight of the dispersion and one or more non-ionic surfactants and wherein at least a part of said non-melt processible polytetrafluoroethylene particles comprise polytetrafluoroethylene polymer chains having repeating units comprising ionic groups. The invention further provides a method for obtaining the dispersions.

대표청구항 ▼

What is claimed is: 1. A composition comprising an aqueous non-melt processible polytetrafluoroethylene dispersion containing non-melt processible polytetrafluoroethylene particles in an amount between 30 and 70% by weight based on the total weight of the dispersion and one or more non-ionic surfac

What is claimed is: 1. A composition comprising an aqueous non-melt processible polytetrafluoroethylene dispersion containing non-melt processible polytetrafluoroethylene particles in an amount between 30 and 70% by weight based on the total weight of the dispersion and one or more non-ionic surfactants, wherein one or more the non-melt processible polytetrafluoroethylene particles comprise polytetrafluoroethylene polymer chains containing repeating units comprising ionic groups, and wherein the total amount of repeating units containing ionic groups is not more than 1% by weight based on the total weight of polytetrafluoroethylene particles comprising polytetrafluoroethylene polymer chains that contain repeating units comprising ionic groups. 2. An aqueous non-melt processible polytetrafluoroethylene dispersion according to claim 1 wherein the ionic groups comprise carboxylic or sulfonic acid groups or salts thereof. 3. An aqueous non-melt processible polytetrafluoroethylene dispersion according to claim 1 wherein the repeating units comprising ionic groups are derivable from a perfluorinated monomer having an ionic group or precursor thereof. 4. An aqueous non-melt processible polytetrafluoroethylene dispersion according to claim 3 wherein the perfluorinated monomer corresponds to the general formula: description="In-line Formulae" end="lead"CF2═CF--O--Rf-Zdescription="In-line Formulae" end="tail" wherein Rf represents a perfluoroalkylene group optionally interrupted by one or more oxygen atoms and Z represents a carboxylic acid group, a salt thereof or a precursor thereof, or a sulfonic acid group, a salt thereof or a precursor thereof. 5. An aqueous non-melt processible polytetrafluoroethylene dispersion according to claim 1 wherein the repeating units containing an ionic group correspond to the general formula: description="In-line Formulae" end="lead"--CF2--CF--O--Rf-Gdescription="In-line Formulae" end="tail" wherein Rf represents a perfluoroalkylene group optionally interrupted by one or more oxygen atoms and G represents a carboxylic acid group or a salt thereof or a sulfonic acid group or a salt thereof and wherein the open valences indicate the linkage of the repeating unit to other repeating units in the polymer chain. 6. An aqueous non-melt processible polytetrafluoroethylene dispersion according to claim 1 wherein the amount of fluorinated surfactant in the dispersion is not more than 200 ppm based on the amount of fluoropolymer solids. 7. An aqueous non-melt processible polytetrafluoroethylene dispersion according to claim 1 wherein the total amount of non-melt processible polytetrafluoroethylene particles is between 45 and 65% by weight and wherein the one or more non-ionic surfactants are present in a total amount of 2 to 15% by weight based on the total weight of polytetrafluoroethylene solids. 8. An aqueous non-melt processible polytetrafluoroethylene dispersion according to claim 1 wherein the non-melt processible polytetrafluoroethylene particles, characterized by polytetrafluoroethylene polymer chains containing repeating units comprising ionic groups, comprise at least 30% by weight of the total weight of non-melt-processible polytetrafluoroethylene particles. 9. A method comprising coating a substrate utilizing an aqueous non-melt processible polytetrafluoroethylene dispersion as defined in claim 1.