Copolymers containing aminoplast units and use thereof as a dispersing agent or stabilizers
View Patent ↗A description is given of water-soluble aminoplast ether copolymers of the following structural type: wherein Z is a glycoluril central unit, B is a radical of an essentially water-insoluble polymer and R1 is a radical of a hydrophilic organic compound. The ratio R1:B is selected within a range of about 1.5 to 4:1 and the overall mass of the water-soluble aminoplast ether copolymer is from about 2000 to 50 000 g/mol such that the copolymer is soluble in water and may be used as a dispersant for e.g. pigments in polar solvents, e.g. water.
1. Water-soluble aminoplast ether copolymers of the following structural type:
where:
Z comprises an aminoplast unit based on a glycolurile of formula
wherein R is selected from the group consisting of hydrogen, alkyl groups, and acyl groups;
B comprises a radical of an essentially water-insoluble polymer selected from poly-n-butyl acrylate, poly-n-butyl methacrylate, polyethyl acrylate, polytetrahydrofuran, polyethyl methacrylate, polymethyl acrylate, polymethyl methacrylate, a predominantly aliphatic polycarbonate and a predominantly aromatic polycarbonate, which are able to react with the OR-function of the aminoplast unit,
R1 comprises a radical of a hydrophilic organic compound containing at least one functional group which is able to react with the OR group of the aminoplast unit to form an ether bond, selected from the group consisting of a radical of methylcellulose, polyacrylic acid, polymethacrylic acid, ethylene/acrylic acid/sodium acrylate copolymer, polyalkylglycol, polyvinyl alcohols and polyvinylpyrrolidone, and
a is at least 1;
wherein the overall mass of the water-soluble aminoplast ether copolymer is from about 2000 to 50 000 g/mol.
2. Aminoplast ether copolymers of claim 1 wherein R is selected from the group consisting of alkyl groups having 1 to about 4 carbon atoms, and acyl groups having 1 to about 4 carbon atoms.
3. Aminoplast ether copolymers of claim 1 wherein R is selected from the group consisting of methyl and ethyl groups.
4. Aminoplast ether copolymers of claim 1 wherein the R1 radical has a molar mass of from about 500 to 30 000 g/mol.
5. Aminoplast ether copolymers of claim 1 wherein the B radical has a molar mass of from about 100 to 30 000 g/mol.
6. A process for preparing an aminoplast ether copolymer of claim 1 comprising reacting the aminoplast unit Z with B and R1 radicals or with prepolymers formed therefrom under acidic catalysts in solution.
7. The process according to claim 6 , wherein the reaction is carried out in a one-pot process in from 15% to 35% strength solution in respect of total reactants used at 70 to 130°C., and, after reacting for about 2 to 10 h, adding a neutralizing agent, to obtain molar masses of the copolymers of from about 2000 to 50 000 g/mol.
8. An Aminoplast ether copolymers obtained by the process of claim 6 .
9. A dispersant or stabilizer for pigments or fillers comprising the aminoplast ether copolymers of claim 1 .
10. The dispersant or stabilizer of claim 9 mixed in an aqueous system.
11. A coating composition, comprising a binder, pigments and/or fillers, and the aminoplast ether copolymer of claim 1 dispersed together.
12. A pigment paste comprising a pigment, a solvent and the aminoplast ether copolymer of claim 1 .
13. The aminoplast ether copolymers of claim 1 wherein the essentially water-insoluble polymer B comprises a hydroxyl function.