Process for drying concrete dispersants

Patent metadata

Field	Value
Publication number	US-9309152-B2
Application number	US-201214235597-A
Country	US
Kind code	B2
Filing date	Jul 31, 2012
Priority date	Aug 10, 2011
Publication date	Apr 12, 2016
Grant date	Apr 12, 2016

Abstract

A process for the production of a solid dispersant for a hydraulically binding composition includes the steps of: providing at least one first polymer, which is a comb polymer having a polymer backbone comprising carboxyl groups; providing at least one second polymer, which is a condensate of, at least, an aromatic compound and formaldehyde; or a lignosulfonate; preparing an aqueous solution comprising the first and the second polymer; and spray-drying the aqueous solution to obtain the solid dispersant.

First claim

The invention claimed is:

1. A process for the production of a solid dispersant for a hydraulically binding composition, comprising the steps of
a) providing at least one first polymer, which is a comb polymer having a polymer backbone comprising carboxyl groups,
b) providing at least one second polymer, which is a condensate of, at least, an aromatic compound and formaldehyde; or a lignosulfonate,
c) preparing an aqueous solution comprising the first and the second polymer, and
d) spray-drying the aqueous solution to obtain the solid dispersant,
wherein the particle size of the spray-dried solid dispersant is below 700 μm and the average particle size (d50%) is between 40 μm and 100 μm.

2. The process according to claim 1 , wherein the backbone of the comb polymer is a polycarboxylic acid and at least some of the side chains of the comb polymer are polyethers.

3. The process according to claim 2 , wherein the side chains of the comb polymer are covalently linked to the polycarboxylic acid backbone by ester, ether and/or amide bonds.

4. The process according to claim 1 , wherein the polycarboxylic acid is polyacrylic acid, polymethacrylic acid or a copolymer of acrylic acid and methacrylic acid.

5. The process according to claim 1 , wherein the side chains comprise polyethyleneglycol and/or polypropyleneglycol.

6. The process according to claim 1 , wherein the average molecular weight (Mw) of the comb polymer is 5,000-150,000 g/mol and/or the average molecular weight of the second polymer is 1,000-50,000 g/mol.

7. The process according to claim 1 , wherein the second polymer is a sulfonate.

8. The process according to claim 1 , wherein the second polymer is a melamine sulfonate formaldehyde condensate, a naphthalene sulfonate formaldehyde condensate, or a lignosulfonate.

9. The process according to claim 1 , wherein the comb polymer and/or the condensate is neutralized or partially neutralized.

10. The process according to claim 1 , wherein the aqueous solution, before spray-drying, comprises
i. 5 to 60% (w/w) first polymers,
ii. 5 to 60% (w/w) second polymers, and
iii. 20 to 80% (w/w) water.

11. The process according to claim 1 , wherein the solid dispersant is in the form of a powder or granulate.

12. A solid dispersant for a hydraulically binding composition, obtained by a process of claim 1 .

13. The solid dispersant of claim 12 , comprising
i. 5 to 95% (w/w) first polymers and
ii. 5 to 95% (w/w) second polymers,
wherein the total amount of polymers i. and ii. is at least 90% (w/w).

14. The solid dispersant of claim 12 in the form of a fine powder, wherein the pH is between 5 and 9.

15. A hydraulically binding composition comprising a solid dispersant of claim 12 .

16. The process according to claim 1 , wherein the second polymer provided in step b) is not phosphatized.

17. The process according to claim 1 , wherein the second polymer provided in step b) is not a polycondensation product containing (I) at least one structural unit with an aromatic or heteroaromatic sub-unit and at least one polyether side chain, and (II) at least one phosphated structural unit with an aromatic or heteroaromatic sub-unit.

18. The process according to claim 8 , wherein the second polymer is a lignosulfonate.

19. The process according to claim 1 , wherein the particle size of the spray-dried solid dispersant is below 250 μm.

20. The process according to claim 1 , wherein the average particle size (d50%) is between 60 μm and 80 μm.

21. The process according to claim 1 , wherein the average molecular weight (Mw) of the comb polymer is 10,000-100,000 g/mol, and/or the average molecular weight of the second polymer is 2,000-10,000 g/mol.

Assignees

• Gallegos Pedro
• Arancibia Lili
• Olivares Hugo
• Croquevielle Ernesto
• Haack Thomas
• Sika Technology Ag

Inventors

• Gallegos Pedro
• Arancibia Lili
• Olivares Hugo
• Croquevielle Ernesto
• Haack Thomas

Classifications

• C04B40/0042 Primary

  Powdery mixtures · CPC title

• C04B24/2658

  containing polyether side chains · CPC title

• C04B24/305 Primary

  Melamine-formaldehyde condensation polymers · CPC title

• C04B24/22

  Condensation {or polymerisation} products thereof · CPC title

• C04B24/18

  Lignin sulfonic acid or derivatives thereof, e.g. sulfite lye · CPC title