Greaseproof paper
View Patent ↗A greaseproof paper is provided for use in food processing and/or packaging of foods in which paper has been rendered oleophobic by treatment with a fluorine-containing polymer. The fluorine-containing polymer may be prepared by polymerizing a fluorine-containing monomer in the presence of a mercapto group-containing organopolysiloxane. The fluorine-containing polymer may be applied to paper by coating onto pre-formed paper, or by applying the polymer as a size during a papermaking process.
1. A fluorine-containing polymer comprising repeating units derived from:
(A) a monomer which comprises a fluorine-containing monomer of the formula:
wherein X is a hydrogen atom, an linear or branched alkyl group having 1 to 21 carbon atoms, a fluorine atom, a chlorine atom, a bromine atom, a iodide atom, a CFX 1 X 2 group (wherein X 1 and X 2 is a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom or a iodide atom.), a cyano group, a linear or branched fluoroalkyl group having 1 to 21 carbon atoms, a substituted or unsubstituted benzyl group, or a substituted or unsubstituted phenyl group,
Y is an aliphatic group having 1 to 10 carbon atoms, an aromatic or cycloaliphatic group having 6 to 10 carbon atoms,
a —CH 2 CH 2 N(R 1 )SO 2 — group (wherein R 1 is an alkyl group having 1 to 4 carbon atoms) or
—CH 2 CH(OY 1 )CH 2 — group (wherein Y 1 is a hydrogen atom or an acetyl group), and Rf is a linear or branched fluoroalkyl group having 1 to 21 carbon atoms,
wherein the fluorine-containing polymer comprises an organopolysiloxane moiety derived from (B) a mercapto group-containing organopolysiloxane,
and also comprises repeating units derived from an olefinically unsaturated monomer (C′) containing an acid phosphate ester, phosphonic acid or acid phosphonate ester group.
2. A polymer according to claim 1 , wherein the Rf group in the fluorine-containing monomer (A) has 1 to 4 carbon atoms.
3. A polymer according to claim 1 , wherein the Rf group in the fluorine-containing monomer (A) is a perfluoroalkyl group.
4. A polymer according to claim 3 , wherein the fluorine-containing polymer also comprises repeating units derived from an olefinically unsaturated fluorine-free and phosphorus-free monomer (C″), and optionally a crosslinkable monomer.
5. A polymer according to claim 1 , wherein the monomer (C′) comprises an acrylate of the general formula:
CH 2 ═CA 1 COOA 3
wherein A 1 is a hydrogen atom, a methyl group or a halogen atom other than a fluorine atom, and
A 3 is a hydrocarbon group having 1 to 30 carbon atoms substituted by an acid phosphate ester, phosphonic acid or acid phosphonate ester group.
6. A polymer according to claim 1 wherein the mercapto functional organopolysiloxane comprises siloxane units having the average formula;
(R 2 SiO) a (RR N SiO) b (RR S SiO) c
where;
a is 0-4000, b is 1-1000, c is 1-1000,
R is independently a monovalent organic group,
R N is a monovalent amino functional organic group, and
R S is a monovalent mercapto functional organic group.
7. A polymer according to claim 1 , wherein the fluorine-containing polymer comprises
5 to 95 wt. % of fluorine-containing monomer (A),
0.1 to 95 wt % of the mercapto organopolysiloxane (B),
0.1 to 70 wt. % of the monomer (C′) containing an acid phosphate ester, phosphonic acid or acid phosphonate ester group and
0 to 70 wt % of an olefinically unsaturated fluorine-free and phosphorus-free monomer (C″).