Stabilized aqueous polymer compositions and their use
Disclosed are stabilized aqueous polymer compositions containing A) a stabilizing amount of a least a sulfur dye or containing a stabilizing amount of a sulfur dye with a compound comprising a heterocyclic system containing nitrogen and sulphur as ring heteroatoms and B) at least one polymer comprising groups which are capable of complex formation with ions. The aqueous polymer compositions are stabilized against thermal or other degradation processes of the polymer by addition of component A) to allow their use even under harsh conditions.
1. A stabilized aqueous polymer composition containing:
A) a stabilizing amount of at least a sulfur dye stabilizer effective to stabilize the aqueous polymer composition against thermal degradation; and
B) at least one polymer comprising groups which are capable of complex formation with ions;
wherein the at least one polymer is selected from the group consisting of
a solvatable polysaccharide and
a synthetic polymer comprising at least two monomer units selected from the group consisting of: an amide of an ethylenically unsaturated carboxylic acid; an ethylenically unsaturated phosphonic acid; and an ethylenically unsaturated sulfonic acid; and
wherein the sulfur dye stabilizer is provided in an amount of from 10 parts of stabilizer per million parts of polymer up to 10% by weight of stabilizer based on the mass of polymer.
2. The stabilized aqueous polymer composition according to claim 1 , wherein said polymer has a molecular weight of at least 10 4 Daltons.
3. The stabilized aqueous polymer composition according to claim 1 , wherein said polymer is selected from the group consisting of starch and its derivatives, a cellulosic derivative, a guar gum and its derivatives, an alginate, a carrageenan, a tragacanth gum, a glucan gum, and a xanthan gum.
4. The stabilized aqueous polymer composition according to claim 1 , wherein said polymer is a synthetic polymer comprising a copolymer of a combination of monomers selected from the group consisting of:
at least one amide of an ethylenically unsaturated carboxylic acid, at least one ethylenically unsaturated phosphonic acid and at least one ethylenically unsaturated sulfonic acid;
at least one amide of an ethylenically unsaturated carboxylic acid, at least one ethylenically unsaturated phosphonic acid, at least one ethylenically unsaturated sulfonic acid and at least one ethylenically unsaturated carboxylic acid;
at least one amide of an ethylenically unsaturated carboxylic acid, at least one ethylenically unsaturated phosphonic acid, at least one ethylenically unsaturated sulfonic acid, and at least one N-vinylamide;
at least one amide of an ethylenically unsaturated carboxylic acid, at least one ethylenically unsaturated phosphonic acid, at least one ethylenically unsaturated sulfonic acid, at least one ethylenically unsaturated carboxylic acid, and at least one N-vinylamide;
at least one amide of an ethylenically unsaturated carboxylic acid, at least one ethylenically unsaturated phosphonic acid, at least one ethylenically unsaturated sulfonic acid, at least one ethylenically unsaturated carboxylic acid, and at least one allylamine; and
at least one amide of an ethylenically unsaturated carboxylic acid, at least one ethylenically unsaturated phosphonic acid, at least one ethylenically unsaturated sulfonic acid, at least one ethylenically unsaturated carboxylic acid, and at least one N-dialkyl alkanolamine.
5. The stabilized aqueous polymer composition according to claim 4 , wherein said synthetic polymer is a copolymer derived from the following combination of monomers: acrylamide, vinylphosphonic acid, 2-acrylamido-2-methylpropane-sulfonic acid and optionally acrylic acid and/or methacrylic acid; or wherein said synthetic polymer is a copolymer containing besides structural units derived from hydrophilic monomers of claim 4 up to 50 weight % of structural units derived from the following hydrophobic ethylenically unsaturated monomers:
vinylester;
vinylether;
alkylester of ethylenically unsaturated carboxylic acids;
ethylenically unsaturated aromates; and
ethylenically unsaturated hydrocarbons.
6. The stabilized aqueous polymer composition according to claim 1 , wherein said synthetic polymer is a graft polymer of hydrophilic and hydrophobic monomer compounds onto hydrophilic or hydrophobic polymer matrices.
7. The stabilized aqueous polymer composition according to claim 1 , wherein said synthetic polymer is a crosslinked polymer derived by addition of monomers with at least two ethylenically unsaturated groups in a molecule during polymerization.
8. The stabilized aqueous polymer composition according to claim 1 , wherein said sulfur dye stabilizer is a sulfur dye, a mixture of sulfur dyes or a sulfur dye combined with other condensed heterocyclic compounds containing nitrogen and sulfur ring systems.
9. The stabilized aqueous polymer composition according to claim 1 , wherein said sulfur dye is a product of the oxidative reaction of heterocyclic compounds containing nitrogen ring atoms and optionally containing sulfur ring atoms with sulfur and/or with natrium polysulfide.
10. The stabilized aqueous polymer composition according to claim 9 , wherein the sulfur dye is a sulfur-bake dye; or wherein the sulfur dye is a polysulfide-bake dye; or wherein the sulfur dye is a polysulfide-melt dye; or wherein the sulfur dye is a sulfurized vat dye; or wherein the sulfur dye is a sulfur dye without CI specification; or wherein the sulfur dye is a solubilized sulfur dye or of combinations of at least two or more thereof.
11. The stabilized aqueous polymer composition according to claim 1 , wherein the stabilizer is a Bunte salt of sulfur dyes prepared by the reaction of sulfur dyes with sulfites.
12. The stabilized aqueous polymer composition according to claim 8 , wherein said condensed heterocyclic compound comprises a heterocyclic system containing nitrogen and sulfur as ring heteroatoms and is selected from the group consisting of phenothiazine, alkyl-substituted phenothiazine, aryl-substituted phenothiazine, aroyl-substituted phenothiazine, carboxyl-substituted phenothiazine, halogen-substituted phenothiazine, N-(dialkylaminoalkyl)-substituted phenothiazine, phenothiazine-5-oxide, alkyl-substituted phenothiazine-5-oxide, aryl-substituted phenothiazine-5-oxide, aroyl-substituted phenothiazine-5-oxide, carboxyl-substituted phenothiazine-5-oxide, halogen-substituted phenothiazine-5-oxide, N-(dialdylaminoalkyl)-substituted phenothiazine-5-oxide and the hydrochlorides of these compounds.
13. The stabilized aqueous polymer composition according to claim 8 , wherein said condensed heterocyclic compound comprises a heterocyclic system containing nitrogen and sulfur as ring heteroatoms and is selected from the group consisting of benzothiazoles, alkyl-substituted benzothiazoles, aryl-substituted benzothiazoles, aroyl-substituted benzothiazoles, sulfonyl-substituted benzothiazoles, halogen-substituted benzothiazoles, amino-substituted benzothiazoles, and mercapto-substituted benzothiazoles.
14. The stabilized aqueous polymer composition according to claim 1 , wherein the polymer is gelled by ionic crosslinking.
15. The stabilized aqueous polymer composition according to claim 1 , wherein the stabilized aqueous polymer composition is obtained by addition of the sulfur dye stabilizer or of the sulfur dye stabilizer and a phenothiazine compound in the form of a powder, of a dispersion or of an emulsion to the at least one polymer followed by ionic crosslinking of said polymer.
16. A method of stabilizing an aqueous polymer system against thermal degradation comprising:
(a) preparing an aqueous polymer composition comprising a polymer with groups capable of complex formation with ions; and
(b) stabilizing the aqueous composition with a sulfur dye or a combination of at least one sulfur dye and another heterocyclic system containing nitrogen and sulfur ring heteroatoms;
wherein the polymer is selected from the group consisting of:
a solvatable polysaccharide and a synthetic polymer comprising at least two monomer units selected from the group consisting of: an amide of an ethylenically unsaturated carboxylic acid; an ethylenically unsaturated phosphonic acid; and an ethylenically unsaturated sulfonic acid.
17. The method of stabilizing an aqueous polymer system according to claim 16 , wherein the stabilized composition is used as a tertiary oil recovery fluid, as a fluid loss additive in drilling muds, as a fluid loss additive in cementing slurries, in polymer compositions for water control, as a cooling lubricant in metal working, in polymer compositions for acidizing processes, or as a friction reducer.
18. A method of recovering oil comprising using a tertiary oil recovery fluid comprising the stabilized aqueous polymer composition of claim 1 .
19. A method of recovering oil comprising using a drilling mud comprising the stabilized aqueous polymer composition of claim 1 .
20. A method of recovering oil comprising using a cement slurry comprising the stabilized aqueous polymer composition of claim 1 .
21. A method of recovering oil comprising using a hydraulic fracturing fluid comprising the stabilized aqueous polymer composition of claim 1 .
22. The stabilized aqueous polymer composition according to claim 3 , wherein said polymer is a cellulosic derivative and wherein further said cellulosic derivative is a cellulose ether selected from the group consisting of carboxymethyl cellulose and hydroxyethyl cellulose.
23. The stabilized aqueous polymer composition according to claim 3 , wherein said polymer is a guar gum derivative and wherein further said guar gum derivative is a guar gum ether.