US2006135681A1PendingUtilityA1

Viscosity control for reduced fluorosurfactant aqueous fluoropolymer dispersions by the addition of cationic surfactant

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Individually held — no corporate assignee on recordPriority: Dec 22, 2004Filed: Dec 2, 2005Published: Jun 22, 2006
Est. expiryDec 22, 2024(expired)· nominal 20-yr term from priority
Inventors:Robert John Cavanaugh
C08F 6/16C08K 5/19C09D 127/18
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Claims

Abstract

A stabilized aqueous fluoropolymer dispersion comprising fluoropolymer particles, wherein the dispersion contains less that about 300 ppm fluorosurfactant based on the weight of the dispersion and a cationic surfactant. The cationic surfactant aids in reducing the viscosity of the dispersion and preferred cationic surfactants are volatile in coating or film casting operations involving drying and sintering of the dispersion.

Claims

exact text as granted — not AI-modified
1 . A stabilized aqueous fluoropolymer dispersion comprising fluoropolymer particles, said dispersion containing less that about 300 ppm fluorosurfactant based on the weight of said dispersion, said dispersion comprising a cationic surfactant.  
   
   
       2 . The dispersion of  claim 1  wherein said fluoropolymer particles have an average particle size or about 100 to about 350 nm.  
   
   
       3 . The dispersion of  claim 1  wherein the solids content of the dispersion is about 30 to about 70 wt %.  
   
   
       4 . The dispersion of  claim 1  wherein the solids content of the dispersion is about 45 to about 70 wt %.  
   
   
       5 . The dispersion of  claim 1  wherein said cationic surfactant is present in an amount of at least about 100 ppm based the weight of the dispersion.  
   
   
       6 . The dispersion of  claim 1  wherein said cationic surfactant is present in an amount of about 100 ppm to about 1000 ppm based on the weight of the dispersion.  
   
   
       7 . The dispersion of  claim 1  further comprising non-ionic surfactant.  
   
   
       8 . The dispersion of  claim 7  wherein said non-ionic surfactant is present in an amount of about 1 to about 5 wt % based the weight of the dispersion.  
   
   
       9 . The dispersion of  claim 1  wherein said cationic surfactant is quaternary ammonium halide or hydroxide.  
   
   
       10 . The dispersion of  claim 8  wherein said cationic surfactant is a compound of the formula:  
     
       
         
         
             
             
         
       
     
     wherein R 1  is a long chain alkyl hydrocarbon, an alkylated aryl hydrocarbon and R 2 , R 3  and R 4  are the same or different and are alkyl groups, the alkyl groups may contain cyclic structures and may be either linear or branched, and Y can be F, Cl, Br or OH.  
   
   
       11 . The dispersion of  claim 10  wherein R 1  is an alkyl group containing between 8 and 28 carbon atoms.  
   
   
       12 . The dispersion of  claim 10  wherein R 1  is an alkyl group containing between 12 and 18 carbon atoms.  
   
   
       13 . The dispersion of  claim 10  wherein R 2 , R 3  and R 4  are the same or different and are selected from the group comprising alkyl groups having 1-16 carbon atoms.  
   
   
       14 . The dispersion of  claim 10  wherein R 2 , R 3  and R 4  are the same or different and are selected from the group comprising methyl or ethyl.  
   
   
       15 . The dispersion of  claim 1  wherein said dispersion contains less than about 100 ppm fluorosurfactant based on the weight of said dispersion.  
   
   
       16 . The dispersion of  claim 1  wherein said dispersion contains less than about 50 ppm fluorosurfactant based on the weight of said dispersion.  
   
   
       17 . A process for reducing fluorosurfactant content of a stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion comprising: 
 reducing the fluorosurfactant content of said stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion to a predetermined level; and    adding cationic surfactant to said dispersion.    
   
   
       18 . The process of  claim 17  wherein said stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion has a solids content of about 15 to about 70 wt %.  
   
   
       19 . The process of  claim 17  wherein said cationic surfactant is added in an amount of at least about 100 ppm based the weight of the dispersion.  
   
   
       20 . The process of  claim 17  wherein said cationic surfactant is added in an amount of at about 100 ppm to about 1000 ppm based the weight of the dispersion.  
   
   
       21 . The process of  claim 17  wherein said stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion comprises nonionic surfactant.  
   
   
       22 . The process of  claim 21  wherein said non-ionic surfactant is present in an amount of about 1 to about 5% based the weight of the dispersion.  
   
   
       23 . The process of  claim 21  further comprising concentrating said dispersion.  
   
   
       24 . The process of  claim 21  wherein said reducing of fluorosurfactant content is performed prior to said concentrating.  
   
   
       25 . The process of  claim 21  wherein said cationic surfactant is added prior to said concentrating.  
   
   
       26 . The process of  claim 17  wherein said stabilized dispersion has a solids content of at least about 25 wt %.  
   
   
       27 . The process of  claim 17  wherein said stabilized dispersion has a solids content of at least about 30 wt %.  
   
   
       28 . The process of  claim 17  wherein said stabilized dispersion has a solids content of at least about 35 wt %.  
   
   
       29 . A process for reducing fluorosurfactant content of a stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion comprising: 
 contacting said stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion with an anion exchange resin to reduce fluorosurfactant content to a predetermined level;    separating said anion exchange resin from said dispersion after the fluorosurfactant content has been reduced; and    adding cationic surfactant to said dispersion.    
   
   
       30 . The process of  claim 29  wherein said anion exchange resin has functional groups selected from the group comprising primary amine, secondary amine, tertiary amine, and quaternary ammonium groups.  
   
   
       31 . The process of  claim 29  wherein said anion exchange resin comprises quaternary ammonium groups.  
   
   
       32 . The process of  claim 29  wherein said anion exchange resin is in hydroxide form.  
   
   
       33 . The process of  claim 29  wherein said contacting said stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion with anion exchange resin reduces fluorosurfactant content to a predetermined level of less than about 300 ppm.  
   
   
       34 . The process of  claim 29  wherein said contacting said stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion with anion exchange resin reduces fluorosurfactant content to a predetermined level of less than about 100 ppm.  
   
   
       35 . The process of  claim 29  wherein said contacting said stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion with anion exchange resin reduces fluorosurfactant content to a predetermined level of less than about 50 ppm.  
   
   
       36 . A process for controlling the viscosity of a stabilized reduced fluorosurfactant aqueous fluoropolymer dispersion comprising: 
 adding a cationic surfactant in an amount sufficient to reduce dispersion viscosity to a predetermined level.

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