Claims
- 1. A process for preparing water-in-oil sulfomethylated polyacrylamide polymers having high reduced specific viscosities (RSV) which comprises reacting a polyacrylamide water-in-oil polysoap latex, said polyacrylamide polymer having a molecular weight of at least about two hundred thousand, with formaldehyde or an adduct of formaldehyde and bisulfite and a molar excess of an alkali metal sulfite as compared with the moles of formaldehyde used, in a reaction mixture which has a water-to-polymer (W/P) ratio of from at least about 2.4 up to about 5, at elevated temperatures above about 100.degree. C. and superatmospheric pressures for a period of from about 1 to about 6 hours to produce a water-in-oil latex terpolymer containing acrylamide, acrylate and sulfomethylacrylamide groups, said alkali metal sulfite being employed in sufficient excess such that the resulting latex has an RSV of at least about 20 and is greater than the RSV of the starting polyacrylamide polymer latex.
- 2. A process according to claim 1 wherein the mol percent excess of alkali metal sulfite to formaldehyde is at least a 50 mol percent excess.
- 3. A process according to claim 1 wherein the alkali metal sulfite is sodium sulfite.
- 4. A process according to claim 1 wherein the reaction is carried out at a temperature above about 120.degree. C.
- 5. A process according to claim 1 wherein the reaction is carried out at a temperature between about 140 and 165.degree. C.
- 6. A process according to claim 1 wherein the reaction is carried out at a temperature of about 165.degree. C.
- 7. A process according to claim 1 wherein the polysoap surfactant employed in the polyacrylamide latex is an ABA type block copolymer of 12-hydroxystearate and polyethylene oxide, with an HLB of 5-6.
- 8. A process according to claim 1 wherein the formaldehyde reactant is separately added gradually to the reaction mixture during the reaction.
- 9. A process according to claim 1 wherein the formaldehyde reactant is separately added gradually to the reaction mixture over a period of at least about 30 minutes.
- 10. A process according to claim 9 wherein the formaldehyde added is an aqueous solution.
- 11. A process according to claim 1 wherein supplemental surfactants are added to the reaction mixture.
- 12. A process according to claim 1 wherein supplemental organic solvent is added to the reaction mixture.
- 13. A process according to claim 1 wherein the resulting water-in-oil latex has an RSV of at least about 20.
- 14. A process according to claim 1 wherein the molar excess of alkali metal sulfite compared to formaldehyde used is present at all times in an amount sufficient t produce a terpolymer latex having an RSV greater than the starting polymer.
Parent Case Info
This application is a continuation-in-part of application Ser. No. 103,165 filed Sept. 30, 1987 now abandoned.
US Referenced Citations (3)
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
103165 |
Sep 1987 |
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