Method for preparing aqueous suspensions of mineral materials using amines in combination with vinyl-carboxylic polymers
The invention relates to the preparation of an aqueous suspension of mineral matter by dispersion and/or grinding in the presence of at least one amine and one vinyl-carboxylic polymer, with the amine allowing to reduce the amount of the polymer and the use of the resulting suspension.
1. A process for preparing an aqueous suspension of mineral matter comprising dispersing and/or grinding an aqueous suspension comprising at least one mineral matter in the presence of (i) at least one amine and (ii) a vinyl-carboxylic polymer completely neutralized by a neutralizing agent selected from the group consisting of calcium hydroxide, calcium oxide, magnesium hydroxide, magnesium oxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, and any mixture thereof, wherein the weight ratio of amine:carboxylic-vinyl polymer is between 0.05:1 and 0.35:1.
2. The process according to claim 1 , wherein the weight ratio of amine:carboxylic-vinyl polymer is between 0.10:1 and 0.25:1.
3. The process according to claim 1 , wherein the amine is selected from group consisting of dimethylamine, monoethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, 2-amino-2-methyl-1-propanol, triisopropanolamine, 2,3,4,6,7,8,9,10-octahydropyrimido[1,2-a]azepine (DBU, CAS No. 6674-22-2), and 2,2-diazabicyclo[2.2.2]octane (DABCO; CAS No. 280-57-9).
4. The process according to claim 1 , wherein the amine has the formula (I):
NR 1 R 2 R 3 (I)
where R 1 , R 2 , R 3 are identical or different, and are chosen from:
hydrogen,
a linear or branched alkyl or oxyalkyl radical having 1 to 12 carbon atoms,
a cycloalkyl radical having from 3 to 12 carbon atoms, or
a linear hydroxyl alkyl radical having 1 to 6 carbon atoms,
provided that:
at most one of R 2 or R 3 groups is hydrogen,
at least one of R 1 , R 2 , R 3 groups contains an OH group, and
at least one of R 1 , R 2 , R 3 groups includes at least one branch in position α to the nitrogen atom.
5. The process according to claim 4 , wherein in formula (I), R 1 is hydrogen, R 2 and R 3 are identical or different, and are chosen from:
a linear or branched alkyl or oxyalkyl radical having 1 to 12 carbon atoms,
a cycloalkyl radical having from 3 to 12 carbon atoms, or
a linear hydroxyl alkyl radical having 1 to 6 carbon atoms,
provided that:
at most one of R 2 or R 3 groups contains an OH group, and
at least one of R 2 or R 3 groups includes at least one branch in position α to the nitrogen atom.
6. The process according to claim 4 , wherein in formula (I), each alkyl or cycloalkyl or oxyalkyl radical comprises from 3 to 10 carbon atoms.
7. The process according to claim 4 , wherein in formula (I), each alkyl or cycloalkyl or oxyalkyl radical comprises from 3 to 8 carbon atoms.
8. The process according to claim 4 , wherein in formula (I), one or more radicals containing the OH group have 3 carbon atoms.
9. The process according to claim 4 , wherein in formula (I), one or more radicals containing the OH group have 2 carbon atoms.
10. The process according to claim 4 , wherein in formula (I), R 1 is hydrogen, R 2 and R 3 are identical or different, and are chosen from:
a linear or branched alkyl or oxyalkyl radical having from 3 to 8 carbon atoms,
a cycloalkyl radical having 6 to 10 carbon atoms, or
a linear hydroxyl alkyl radical having from 2 to 3, preferably 2 carbon atoms, provided that:
at least one of R 2 or R 3 groups contains an OH group, and
at least one of R 2 or R 3 groups includes at least one branch in position α to the nitrogen atom.
11. The process according to claim 4 , wherein the amine is selected from the group consisting of:
N-(1-methylpropyl)-N-(2-hydroxyethylamine),
N-(1,3-dimethylbutyl)-N-(2-hydroxyethylamine),
N-(1-ethyl-3-methylpentyl)-N-(2-hydroxyethylamine),
N-(3,3′,5-trimethylcyclohexyl)-N-(2-hydroxyethylamine), and
N-(4-hydroxycyclohexyl)-N-(2-hydroxyethylamine).
12. The process according to claim 1 , wherein the vinyl-carboxylic polymer has carboxylic acid cites that are completely neutralized by (i) sodium ions, (ii) a combination of sodium and calcium ions, or (iii) a combination of magnesium and sodium ions.
13. The process according to claim 1 , wherein the vinyl-carboxylic polymer is a homopolymer of acrylic acid or a copolymer of acrylic acid with another monomer.
14. The process according to claim 13 , wherein the vinyl-carboxylic polymer is a copolymer of acrylic acid with another monomer selected from methacrylic acid, maleic anhydride, 2-acrylamido-2-methyl propane sulfonic acid, phosphoric esters of (meth)acrylates of alkylene glycol and non-ionic monomers of formula (II):
where m, n, p and q are integers and m, n, p are less than 150, q is greater than 0 and at least one integer m, n and p is not zero, R is a radical with a polymerizable unsaturated function, R 1 and R 2 are identical or different and represent hydrogen atoms or alkyl groups, R′ represents hydrogen or a hydrocarbon radical having 1 to 40 carbon atoms, or an ionic group or ionizable.
15. The process according to claim 1 , wherein the aqueous suspension of mineral matter has a solids content of between 10% and 82%.
16. The process according to claim 1 , wherein the aqueous suspension of mineral matter has a solids content of between 50% and 81%.
17. The process according to claim 1 , wherein the aqueous suspension of mineral matter has a solids content of between 65% and 78%.
18. The process according to claim 1 , wherein the aqueous suspension of mineral matter has between 0.01% and 5% of vinyl-carboxylic polymer based on dry weight of mineral matter.
19. The process according to claim 1 , wherein the aqueous suspension of mineral matter has between 0.01% and 2% of vinyl-carboxylic polymer based on dry weight of mineral matter.
20. The process according to claim 1 , wherein the aqueous suspension of mineral matter has between 0.05% and 1% of vinyl-carboxylic polymer based on dry weight of mineral matter.
21. The process according to claim 1 , wherein the mineral matter is natural calcium carbonate, precipitated calcium carbonate, talc, kaolin, or any mixture thereof.
22. The process according to claim 1 , wherein the mineral matter is natural calcium carbonate.
23. The process according to claim 22 , wherein the natural calcium carbonate comprises limestone, marble, calcite, chalk, dolomite, or any mixture thereof.
24. The process according to claim 1 , wherein the aqueous suspension of mineral matter after dispersing and/or grinding is concentrated.
25. A filler, paper coating, paint or plastic made from the aqueous suspension of mineral matter obtained from the process of claim 1 .