Method for making fluoropolymers
AssigneeSolvay Specialty Polymers Italy S.P.A.
InventorsMarco Avataneo, Ugo De Patto, Giuseppe Marchionni, Mirko Tavano
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Abstract
The invention pertains to a method of making fluoropolymer dispersions using certain polyfunctional perfluoropolyether derivatives including a plurality of ionisable groups selected from the group consisting of —SO.sub.3X.sub.a, —PO.sub.3X.sub.a and —COOX.sub.a, whereas X.sub.a is H, an ammonium group or a monovalent metal, and whereas said groups are comprised as pendant groups in the perfluoropolyether chain, and to fluoropolymer dispersions therefrom.
Claims16
A method for making a fluoropolymer, the method comprising emulsion polymerizing one or more than one fluorinated monomer in an aqueous medium wherein said aqueous emulsion polymerization is carried out in an aqueous medium in the presence of at least one radical initiator and at least one dispersant (D), wherein dispersant (D) is at least one polyfunctional perfluoropolyether dispersant comprising a plurality of ionisable groups (X) of —COOXa, wherein Xa is H, an ammonium group or a monovalent metal, optionally in combination with sulfonic acid groups of formula —SO3Xa and/or phosphonic acid groups of formula PO3Xa, and complying with formula:
- TX-O—[Rf1—O]n1[Rf2—O]n2-TX′ (I)
- wherein:
- each of Rf1, equal to or different from each other at each occurrence, is a C1-C4 perfluoroalkylene group;
- each of Rf2, equal to or different from each other at each occurrence, is a C1-C4 perfluoroalkylene group comprising at least one group (X), as above detailed;
- n1 and n2 are positive numbers different from zero;
- and
- TX and TX′, equal to or different from each other, are selected from the group consisting of:
- (j) C1-C24 (hydro)(fluoro)carbon groups free from group (X), as above detailed, optionally comprising one or more than one of H, O, and Cl;
- and
- (jj) C1-C24 (hydro)(fluoro)carbon groups comprising at least one group (X), as above detailed;
- and
- said dispersant (D) possessing a number averaged molecular weight of more than 3000 and of at most 25000;
- and
- wherein the amount of said ionisable groups in dispersant (D) is at least 0.35 meq/g.
A fluoropolymer dispersion comprising fluoropolymer particles and at least one dispersant (D), wherein dispersant (D) is at least one polyfunctional perfluoropolyether dispersant comprising a plurality of ionisable groups (X) of —COOXa, whereas Xa is H, an ammonium group or a monovalent metal, optionally in combination with sulfonic acid groups of formula —SO3Xa and/or phosphonic acid groups of formula PO3Xa, and complying with formula:
- TX-O—[Rf1—O]n1[Rf2—O]n2-TX′ (I)
- wherein:
- (i) each of Rf1, equal to or different from each other at each occurrence, is a C1-C4 perfluoroalkylene group;
- (ii) each of Rf, equal to or different from each other at each occurrence, is a C1-C4 perfluoroalkylene group consisting at leas one group (X), as above detailed;
- and
- (iii) n1 and n2 are positive numbers different from zero;
- and
- TX and TX′, equal to or different from each other, are selected from the group consisting of:
- (j) C1-C24 (hydro)(fluoro)carbon groups free from group (X), as above detailed, optionally comprising one of more than one of H, O, and Cl;
- and
- (jj) C1-C24 (hydro)(fluoro)carbon groups comprising at least one group (X), as above detailed;
- and
- said dispersant (D) possessing a number of averaged molecular weight of more than 3000 and of at most 25000;
- and
- wherein the amount of said ionisable groups in dispersant (D) is at least 0.35 meq/g.
Dependencies are inferred from the claim text.