Viscosity suppression of associative thickeners using organophosphates
The viscosity of solutions of nonionic synthetic associative thickeners is controlled by adding organophosphates to the solution of associative thickeners. The associative thickeners are hydrophobically modified polymers and the organophosphates include one or more hydrophobic groups.
1. An associative thickener composition comprising:
1) a water dispersible polymer modified with a first hydrophobic group; and
2) a low VOC organophosphate represented by one or both of the following formulas:
wherein M represents a counter cation, x and y are 0-12, R 1 is chosen as the same as said first hydrophobic group, and R 2 is selected from the group consisting of said first hydrophobic group and a second hydrophobic group with 19 or less carbon atoms, and
wherein the water dispersible polymer modified with said first hydrophobic group is selected from the group consisting of hydrophobically modified ethylene oxide urethane (HEUR) block copolymers, aminated HEURs, hydrophobically modified polyacetal polyethers (HM-PAPEs), hydrophobically modified aminoplast polyethers, hydrophobically modified polyacrylates and polymethacrylates (HM-PA and HM-PMA), hydrophobically modified polysaccharides, and combinations thereof, and
wherein an aqueous solution or dispersion of said associative thickener composition has a lower viscosity than an aqueous solution or dispersion of said water dispersible polymer without said low VOC organophosphate.
2. The associative thickener composition of claim 1 , wherein said first hydrophobic group is a C 8 -C 19 alkyl.
3. The associative thickener composition of claim 2 , wherein said first hydrophobic group is a branched alkyl.
4. The associative thickener composition of claim 3 , wherein said first hydrophobic group is ethylhexyl.
5. The associative thickener composition of claim 1 , wherein said first hydrophobic group is a hydrophobic moiety selected from the group consisting of linear alkyl, branched alkyl, alkenyl, alkylaryl, arylalkyl, arylalkenyl, cycloaliphatic polycyclic, and combinations thereof.
6. The associative thickener composition of claim 1 , wherein said first hydrophobic group is a C 5 -C 19 alkyl and at least one of R 1 and R 2 is a C 5 -C 19 alkyl.
7. The associative thickener composition of claim 6 , wherein said first hydrophobic group is a branched alkyl and at least one of R 1 and R 2 is a branched alkyl.
8. The associative thickener composition of claim 7 , wherein said first hydrophobic group is ethylhexyl.
9. The associative thickener composition of claim 6 , wherein R 2 is an alkyl group having more carbon atoms than R 1 and y is greater than x.
10. The associative thickener composition of claim 9 , wherein y is greater than or equal to 6.
11. The associative thickener composition of claim 10 , wherein R 2 is tridecyl.
12. The associative thickener composition of claim 6 , wherein said organophosphate is a co-ester.
13. The associative thickener composition of claim 12 , wherein R 1 is isooctyl and R 2 is tridecyl.
14. The associative thickener composition of claim 12 , wherein R 1 is C 5 -C 10 alkyl, x equals to 1, R 2 is an alkyl group having at least 11 carbon atoms, and y is greater than 1.