Pigment dispersions containing dispersants having pendent hydrophilic polymeric segments prepared by controlled radical polymerization
First Claim
1. A pigment dispersion comprising:
- (a) pigment;
(b) an aqueous carrier selected from water and a mixture of water and at least one organic solvent; and
(c) a pigment dispersant prepared by polymerizing a composition comprising, (i) at least one prepolymer having a radically polymerizable group at a head end of said prepolymer and an initiator residue at a tail end, said prepolymer being prepared by controlled radical polymerization of at least one radically polymerizable ethylenically unsaturated first monomer, said prepolymer having a polydispersity index of less than 2.0; and
(ii) at least one radically polymerizable ethylenically unsaturated second monomer to produce a polymer backbone segment in said pigment dispersant;
wherein said prepolymer after polymerization with (c)(ii) is in the form of polymeric segments pendent to said polymeric backbone segment, at least a portion of each pendent polymeric segment is hydrophilic, and the polymeric backbone segment is hydrophobic, wherein the pigment dispersant has the following structure;
where M represents a residue of the radically polymerizable ethylenically unsaturated second monomer (c)(ii);
x is the number of occurrences of M randomly distributed along the polymer chain;
T-(E)s-(G)p-Φ
represents the prepolymer;
y is the number of occurrences of the prepolymer randomly distributed along the polymer chain;
T represents the radically polymerizable group at the head end of said prepolymer;
E represents a block of hydrophilic residues of at least one radically polymerizable ethylenically unsaturated monomer;
G represents a block of residues of one or more monomers selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, alkyl (meth)acrylates having from 6 to 20 carbon atoms in the alkyl group and an oxirane monomer reacted with a carboxylic acid;
Φ
represents the initiator residue, x and y are selected such that the total weight ratio of the prepolymer (c)(i) to M (c)(ii) is from 1;
10 to 10;
1;
p is from 1 to 300; and
s is from 1 to 300.
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Abstract
A pigment dispersion comprising pigment, an aqueous carrier selected from water and a mixture of water and at least one organic solvent, and a pigment dispersant is described. The pigment dispersant is prepared by polymerizing (i) at least one prepolymer having a radically polymerizable group, and (ii) at least one second monomer. The prepolymer is prepared by controlled radical polymerization, e.g., atom transfer radical polymerization, of at least one radically polymerizable first monomer. The second monomer forms a polymeric backbone segment of the pigment dispersant, and the prepolymer forms polymeric segments that are pendent to the backbone. The backbone segment of the pigment dispersant in hydrophobic, while at least a portion of each pendent polymeric segment is hydrophilic.
41 Citations
26 Claims
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1. A pigment dispersion comprising:
-
(a) pigment;
(b) an aqueous carrier selected from water and a mixture of water and at least one organic solvent; and
(c) a pigment dispersant prepared by polymerizing a composition comprising, (i) at least one prepolymer having a radically polymerizable group at a head end of said prepolymer and an initiator residue at a tail end, said prepolymer being prepared by controlled radical polymerization of at least one radically polymerizable ethylenically unsaturated first monomer, said prepolymer having a polydispersity index of less than 2.0; and
(ii) at least one radically polymerizable ethylenically unsaturated second monomer to produce a polymer backbone segment in said pigment dispersant;
wherein said prepolymer after polymerization with (c)(ii) is in the form of polymeric segments pendent to said polymeric backbone segment, at least a portion of each pendent polymeric segment is hydrophilic, and the polymeric backbone segment is hydrophobic,wherein the pigment dispersant has the following structure;
where M represents a residue of the radically polymerizable ethylenically unsaturated second monomer (c)(ii);
x is the number of occurrences of M randomly distributed along the polymer chain;
T-(E)s-(G)p-Φ
represents the prepolymer;
y is the number of occurrences of the prepolymer randomly distributed along the polymer chain;
T represents the radically polymerizable group at the head end of said prepolymer;
E represents a block of hydrophilic residues of at least one radically polymerizable ethylenically unsaturated monomer;
G represents a block of residues of one or more monomers selected from the group consisting of methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, alkyl (meth)acrylates having from 6 to 20 carbon atoms in the alkyl group and an oxirane monomer reacted with a carboxylic acid;
Φ
represents the initiator residue, x and y are selected such that the total weight ratio of the prepolymer (c)(i) to M (c)(ii) is from 1;
10 to 10;
1;
p is from 1 to 300; and
s is from 1 to 300.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification