HIGH MOLECULAR WEIGHT POLYMERIC DISPERSIONS WITH METAL SCAVENGER
Methods for manufacturing a polymer dispersion, polymer dispersions, and their use are provided herein. The methods of manufacturing the polymer dispersion comprise the steps of providing a reaction mixture in an aqueous medium comprising a polymeric dispersant and a monomer composition comprising radically polymerizable monomers, and subjecting the monomer composition in the reaction mixture to a radical polymerization to synthesize a dispersed polymer so as to form the polymer dispersion, wherein the radical polymerization is performed in presence of a metal scavenger system comprising a metal scavenger and an acid. These polymer dispersions are designated as water-in-water (w/w) polymer dispersions.
1 . A method for manufacturing a polymer dispersion comprising the steps of
C) providing a reaction mixture in an aqueous medium comprising
a) a polymeric dispersant and
b) a monomer composition comprising radically polymerizable monomers, wherein the radically polymerizable monomers are selected from the group of one or more of a non-ionic ethylenically unsaturated monomer, a cationic ethylenically unsaturated monomer, or an amphiphilic ethylenically unsaturated monomer;
D) subjecting the monomer composition in the reaction mixture to a radical polymerization to synthesize a dispersed polymer and to form the polymer dispersion, wherein step B is performed in the presence of a metal scavenger system comprising an acid and a metal scavenger, which metal scavenger is a first carboxylic acid comprising 2, 3, 4, or 5 carboxylic acid groups and at least one nitrogen atom, and wherein the pH at the beginning of step B is from 4.5 to and
E) stabilizing the polymer dispersion by adding a second carboxylic acid.
2 . The method according to claim 1 , wherein step C) is performed by adding the second carboxylic acid at a temperature of less than 40° C.
3 . The method according to claim 1 , wherein the acid is an inorganic acid.
4 . The method according to claim 1 , wherein the pH at the beginning of step B is from 4.7 to 5.1.
5 . The method according to claim 1 , wherein the second carboxylic acid comprises 1, 2, or 3 carboxylic acid groups and no nitrogen atom.
6 . The method according to claim 1 , wherein the radically polymerizable monomers are selected from the group of one or more of the following:
i. a non-ionic monomer of formula (I)
where
R 1 means hydrogen or methyl;
R 2 and R 3 are, independently of each other, hydrogen, C 1 -C 5 -alkyl or
C 1 -C 5 -hydroxyalkyl,
ii. a cationic monomer of formula (II)
where
R 1 means hydrogen or methyl;
Z 1 is O, NH or NR 4 , wherein R 4 means C 1 -C 4 -alkyl, and
Y is one of
where
Y 0 and Y 1 are a C 1 -C 6 alkylene group, optionally substituted with one or more hydroxy groups;
Y2, Y3, Y5, Y6, Y7 independently of each other, are each C 1 -C 6 -alkyl; and
Z − is a counterion;
iii. an amphiphilic monomer of formulae (III) or (IV)
where
Z 1 is O, NH, NR 4 , wherein R 4 means C 1 -C 4 -alkyl,
R 1 means hydrogen or methyl,
R 8 is a C 1 -C 6 alkylene group,
R 5 and R 6 are, independently of each other, each C 1 -C 6 -alkyl, preferably methyl,
R 7 is a C 8 -C 32 alkyl, optionally substituted with one or more hydroxy groups, and
Z − is a counterion; or
where
Z 1 is O, NH, NR 4 , wherein R 4 means C 1 -C 4 -alkyl,
R 1 means hydrogen or methyl,
R 10 means hydrogen, C 8 -C 32 alkyl, C 8 -C 32 aryl and/or C 8 -C 32 aralkyl,
R 9 is a C 1 -C 6 alkylene group, and
n is an integer between 1 and 50; or
iv. an ethylenically unsaturated cross-linker containing 2, 3, 4 or 5 ethylenically unsaturated groups.
7 . The method according to claim 1 , wherein the monomer composition comprising the radically polymerizable monomers at least comprises the non-ionic monomer of formula (I) being selected from those in which R 1 means hydrogen or methyl, and R 2 and R 3 are both hydrogen, hydrogen and C1-C3 alkyl, hydrogen and hydroxyethyl, or both C 1 -C 3 alkyl, and/or the cationic monomer of formula (II) being selected from those in which R 1 means hydrogen or methyl, and Z 1 is O, NH or NR 4 , wherein R 4 means methyl, Y 1 is C 2 -C 6 alkylene, preferably ethylene or propylene, Y 5 , Y 6 and Y 7 are all methyl, and Z − is a halogen.
8 . The method according to claim 1 , wherein the monomer composition comprises at least 5 wt.-% of the non-ionic monomer of formula (I)
where
R 1 means hydrogen or methyl;
R 2 and R 3 are, independently of each other, hydrogen, C 1 -C 5 -alkyl or C 1 -C 5 -hydroxyalkyl;
at least 5 wt.-% of the cationic monomer of formula (II)
where
R 1 means hydrogen or methyl;
Z 1 is O, NH or NR 4 , wherein R 4 means C 1 -C 4 -alkyl, and
Y is one of
where
Y 0 and Y 1 are a C 1 -C 6 alkylene group, optionally substituted with one or more hydroxy groups;
Y2, Y3, Y5, Y6, Y7 independently of each other, are each C 1 -C 6 -alkyl; and
Z − is a counterion;
0 to 1.25 wt.-% of the ethylenically unsaturated cross-linker containing 2, 3, 4 or 5 ethylenically unsaturated groups; and
optionally, further ethylenically unsaturated monomers.
9 . The method according to claim 1 , wherein the polymeric dispersant is a homopolymer made of the cationic monomer of formula (II)
where
R 1 means hydrogen or methyl;
Z 1 is O, NH or NR 4 , wherein R 4 means C 1 -C 4 -alkyl, and
Y is one of
where
Y 0 and Y 1 are a C 1 -C 6 alkylene group, optionally substituted with one or more hydroxy groups;
Y2, Y3, Y5, Y6, Y7 independently of each other, are each C 1 -C 6 -alkyl; and
Z − is a counterion.
10 . The method according to claim 1 , wherein the polymeric dispersant is a homopolymer made of a (meth)acryloyl amidopropyl trimethylammonium salt or a (meth)acryloyl oxyethyl trimethylammonium salt.
11 . The method according to claim 1 , wherein step B) is conducted by sequentially or simultaneously adding to the reaction mixture redox initiator system comprising an oxidizing agent and a reducing agent.
12 . The method according to claim 1 , wherein the ethylenically unsaturated cross-linker is a cross-linker containing 2 or 3 ethylenically unsaturated groups.
13 . A polymer dispersion comprising
c) a polymeric dispersant and
d) dispersed polymer derived from a monomer composition comprising radically polymerizable monomers, wherein the radically polymerizable monomers are selected from the group of one or more of a non-ionic ethylenically unsaturated monomer, a cationic ethylenically unsaturated monomer, or an amphiphilic ethylenically unsaturated monomer;
wherein the polymer dispersion comprises a metal scavenger system comprising a first carboxylic acid as a metal scavenger and an inorganic acid, and wherein the polymer dispersion comprises a second carboxylic acid.
14 . A polymer dispersion obtained by a method for manufacturing the polymer dispersion according to claim 1 comprising the steps of
A) providing a reaction mixture in an aqueous medium comprising
a) a polymeric dispersant and
b) a monomer composition comprising radically polymerizable monomers, wherein the radically polymerizable monomers are selected from the group of one or more of a non-ionic ethylenically unsaturated monomer, a cationic ethylenically unsaturated monomer, or an amphiphilic ethylenically unsaturated monomer;
B) subjecting the monomer composition to a radical polymerization to synthesize a dispersed polymer and to form the polymer dispersion, wherein step B is performed in presence of a metal scavenger system comprising an acid and a metal scavenger, which metal scavenger is a first carboxylic acid comprising 2, 3, 4, or 5 carboxylic acid groups and at least one nitrogen atom, and wherein the pH at the beginning of step B is from 4.5 to 5.3; and
C) stabilizing the polymer dispersion by adding a second carboxylic acid.