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US 6,346,588 B1Granted
Terpolymers based on sulfobetaines, processes for their preparation and their use as thickeners for aqueous salt solutions
AssigneeSKW Polymers GmbH
InventorsAndrea Fenchl, Johann Plank, Michael Schinabeck
Life of this patent
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Abstract
Terpolymers based on (meth)acrylamide, hydroxyalkyl (meth)acrylate and sulfobetaine monomers and their use as thickeners for aqueous salt solutions are described. The terpolymers display their thickening effect within wide concentration and density ranges of the aqueous salt solutions. In addition, their thermal stability is retained also with respect to salt solutions containing calcium chloride and/or calcium bromide and/or zinc bromide.
Claims7
A terpolymer based on sulfobetaines, which is composed of
- a) from 5 to 79 mol % of structural units of the general formula I
- in which R1 denotes H or CH3 and R2 and R3, independently of one another, denote H, a C1-4-alkyl or phenyl radical,
- b) from 20 to 94 mol % of structural units of the general formula II
- in which R1 represents H or CH3 and m represents 1 to 4, and
- c) from 1 to 75 mol % of structural units of the general formula III
- in which X is selected from the group consisting of
- in which R4 denotes —(CH2)m—,
- m denotes 1 to 4 and
- n denotes 0 to 3 and R1, R2 and R3 have the abovementioned meaning.
6 more elements
Dependencies are inferred from the claim text.