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US 11,142,601 B2Granted
Aqueous polymer dispersion and aqueous coating composition comprising the same
AssigneesDow Global Technologies LLC, Rohm and Haas Company
InventorsXiaohong Yang, Tao Wang
Life of this patent
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Abstract
An aqueous dispersion of a multistage polymer, an aqueous coating composition having an extended open time and capable of providing coatings with good water resistance, and a process of preparing the coatings.
Claims16
An aqueous dispersion of a multistage polymer, wherein the multistage polymer comprises:
- (A) a first polymer comprising as polymerized units, based on the weight of the first polymer,
- (a1) from 2.1% to 10% by weight of diacetone (meth)acrylamide, a hydroxy-functional (meth)acrylic acid alkyl ester, or mixtures thereof,
- (a2) from 2.8% to 10% by weight of a phosphorous-containing acid monomer,
- (a3) from 75% to 92% by weight of a hydrophilic (meth)acrylic acid alkyl ester, and
- (a4) from 0 to 3.8% by weight of an α, β-ethylenically unsaturated carboxylic acid;
- wherein the first polymer has a number average molecular weight of from 3,000 to 20,000;
- and
- (B) a second polymer comprising as polymerized units, based on the weight of the second polymer,
- (b1) from 50% to 100% by weight of a hydrophobic (meth)acrylic acid alkyl ester,
- (b2) from 0 to 10% by weight of a carbonyl-containing functional monomer, and
- (b3) from 0 to 50% by weight of a hydrophilic monomer;
- wherein the second polymer has a glass transition temperature at least 40° C. lower than that of the first polymer, and the weight ratio of the first polymer to the second polymer is from 25:75 to 50:50.
9 more elements
A process of preparing an aqueous dispersion of a multistage polymer by a multistage free-radical polymerization, comprising:
- (i) preparing a first polymer in an aqueous medium by a free-radical polymerization in the presence of a chain transfer agent and neutralizing the obtained first polymer to a pH value of at least 6, wherein the first polymer comprises as polymerized units, based on the weight of the first polymer,
- (a1) from 2.1% to 10% by weight of diacetone (meth)acrylamide, a hydroxy-functional (meth)acrylic acid alkyl ester, or mixtures thereof,
- (a2) from 2.8% to 10% by weight of a phosphorous-containing acid monomer,
- (a3) from 75% to 92% by weight of a hydrophilic (meth)acrylic acid alkyl ester, and
- (a4) from 0 to 3.8% by weight of an α, β-ethylenically unsaturated carboxylic acid;
- and
- (ii) preparing a second polymer in the presence of the first polymer obtained from step (i) by a free-radical polymerization, wherein the second polymer comprises as polymerized units, based on the weight of the second polymer,
- (b1) from 50% to 100% by weight of a hydrophobic (meth)acrylic acid alkyl ester,
- (b2) from 0 to 10% by weight of a carbonyl-containing functional monomer, and
- (b3) from 0 to 50% by weight of a hydrophilic monomer;
- wherein the second polymer has a glass transition temperature at least 40° C. lower than that of the first polymer, and the weight ratio of the first polymer to the second polymer is from 25:75 to 50:50 and wherein the number average molecular weight of the first polymer is from 3000 to 20,000.
8 more elements
Dependencies are inferred from the claim text.