Claims
- 1. A process for producing water-in-oil emulsions of a polymer from at least one ethylenically-unsaturated monomer comprising the steps of
- (a) forming an aqueous phase comprising an aqueous solution containing at least one ethylenically-unsaturated, water-soluble monomer;
- (b) forming an oil phase comprising a hydrophobic liquid and an oil-soluble surfactant;
- (c) blending said aqueous phase and oil phase to form a water-in-oil emulsion of said monomer;
- (d) initiating polymerization of said monomer in said emulsion by heating said emulsion in the presence of a first polymerization initiator capable of initiating polymerization of said monomer at a temperature less than about 45.degree. C.; and
- (e) after a small amount of polymer is formed sufficient to provide a shear-stable monomer emulsion, completing said polymerization in the presence of a second polymerization initiator capable of initiating polymerization of said monomer at a second temperature which is both higher than about 40.degree. C. and higher than said first temperature.
- 2. The process of claim 1 wherein said first initiator comprises a free-radical initiator capable of polymerizing said monomer at a temperature of from about 0.degree. to about 45.degree. C.
- 3. The process of claim 1 wherein said second initiator comprises a free-radical initiator capable of polymerizing said monomer at a temperature of from about 40.degree. to about 100.degree. C.
- 4. The process of claim 1 wherein said oil phase also contains at least one hydrophobic monomer having a water solubility of less than about 10 weight percent.
- 5. The process of claim 4 wherein said hydrophobic monomer is selected from the group consisting of vinyl esters, alkyl acrylates, alkyl methacrylates, vinyl ethers, acrylonitrile, styrene, N-vinyl carbazole, and vinyl halides.
- 6. The process of claim 1 wherein said monomer is selected from the group consisting of acrylic and methacrylic acids and salts thereof; acrylamide; methacrylamide; and acrylamido-and methacrylamido monomers of the formula ##STR28## wherein R.sub.6 is a hydrogen atom or a methyl group; R.sub.7 is a hydrogen atom or an alkyl group having from 1 to 2 carbon atoms; R.sub.8 is an alkyl group having from 1 to 2 carbon atoms or --R.sub.9 --SO.sub.3 X wherein R.sub.9 is a divalent hydrocarbon group having from 2 to 13 carbon atoms and X is a monovalent cation.
- 7. The process of claim 1 wherein said hydropholic liquid is selected from the group consisting of benzene, xylene, toluene, mineral oils, kerosenes, petroleum and mixtures thereof.
- 8. The process of claim 1 wherein said oil-soluble surfactant has a Hydrophile-Lipophile Balance (HLB) of from about 1 to about 10.
- 9. The process of claim 1 wherein said second temperature is higher than said first temperature by at least about 5.degree. C.
- 10. The process of claim 1 wherein said first initiator attains a half-life at a temperature which is at least about 20.degree. C. less than the temperature at which said second initiator attains the same half-life.
- 11. The process of claim 1 wherein said polymer is represented by the following formula: ##STR29## wherein R.sub.15, R.sub.16, and R.sub.18 are each a hydrogen atom or a methyl group; R.sub.17.sup.+ is an alkali metal atom or an ammonium group, R.sub.19 is --OR.sub.20, ##STR30## phenyl, substituted phenyl, --CN, ##STR31## wherein R.sub.20 is an alkyl group having up to 5 carbon atoms; wherein R.sub.21 is a methyl or ethyl group, and wherein R.sub.22 is an alkyl group having up to 8 carbon atoms; a is from about 5 to about 90 mole %, b is from about 5 to about 90 mole %, c is from about 0.2 to about 20 mole % with the proviso that a+b+c=100 mole %; and d is an integer of from about 1,000 to about 500,000.
- 12. The process of claim 11 wherein said polymer is a terpolymer represented by the formula; ##STR32## wherein R.sub.17 + is Na+, or K+ or NH.sub.4 +; R.sub.21 is a methyl, ethyl or butyl group; f is from about 30 to about 60 mole %, g is from about 30 to about 60 mole % and h is from about 0.2 to about 20 mole %, with the proviso that f+g+h=100 mole %.
- 13. The process of claim 11 wherein said polymer is represented by the following formula: ##STR33## wherein R.sub.15, R.sub.16, R.sub.17.sup.+, R.sub.18, R.sub.19, a, b, c and d are as defined in claim 11; wherein e is from about 0.1 to less than about 20 mole % and with the proviso a+b+(c-e)+e=100 mole %.
- 14. The process of claim 13 wherein said polymer is represented by the formula: ##STR34## wherein R.sub.15, R.sub.16, R.sub.17.sup.+, R.sub.18, R.sub.21, d and e are as defined in claim 13; wherein f is from about 30 to about 60 mole %, g is from about 30 to about 60 mole % and h is from about 0.2 to about 20 mole %, with the proviso that f+g+(h-e)+e=100 mole %.
- 15. The process of claim 1 wherein said polymer is represented by the formula ##STR35## wherein A represents a repeating unit derived from a hydrophobic vinyl monomer having a water-solubility of less than about 5 weight percent; R.sub.23 and R.sub.25 are each a hydrogen atom or a methyl group; R.sub.26 and R.sub.27 are each a hydrogen atom, a methyl group or an ethyl group; R.sub.24 represents a divalent hydrocarbon group having from 2 to 13 carbon atoms; X represents a monovalent cation; B represents a repeating unit derived from an ethylenically-unsaturated carboxylic acid or a salt thereof; m is from about 0.1 to 10 mole %, n is from about 1 to 40 mole %, p is from about 20 to 98.9 mole % and q is 0 to about 40 mole %, with the proviso that m+n+p+q=100 mole %; and r is a large positive integer.
- 16. The process of claim 15 wherein said polymer is a terpolymer represented by the formula: ##STR36## wherein A' represents ##STR37## wherein R.sub.28 is --H or --CH.sub.3 and R.sub.29 is ##STR38## a halogen atom, --O--R.sub.32, --CN or ##STR39## wherein R.sub.30 is an alkyl group having from 1 to 12 carbon atoms, R.sub.31 is an alkyl group having from 1 to 4 carbon atoms, R.sub.32 is an alkyl group having from 1 to 6 carbon atoms, and R.sub.33 is a hydrogen atom, a methyl group or an ethyl group; R.sub.24 is an alkylene group having from 2 to 8 carbon atoms, a cycloalkylene group having from 6 to 8 carbon atoms or phenylene; R.sub.25, R.sub.26 and R.sub.27 are as defined in claim 15; X is a hydrogen atom, an ammonium group, an organo-ammonium group or an alkali metal atom, m' and n' are the same as m and n, respectively, and p' is from about 50 to 98.9 mole %, wherein m'+n'+p'=100 mole %; and wherein r' is a large positive integer such that the molecular weight of the polymer is greater than 500,000.
- 17. The process of claim 16 wherein said polymer is represented by the following formula: ##STR40## wherein R.sub.23, R.sub.24, R.sub.25, R.sub.26, R.sub.27, R.sub.28, R.sub.29, X, m', n', p', and r' are as defined in claim 16, and wherein z' is from about 0.1 to less than about 10 mole % and wherein (m'-z')+n'+p'+z'=100 mole %.
- 18. The process of claim 16 wherein said terpolymer comprises a polymer resulting from the polymerization of a water-in-oil monomer emulsion containing about 8-12 mole % sodium-2-acrylamido-2-methylpropane sulfonate monomer, about 87-91 mole % acrylamide monomer and about 1-5 mole % of vinyl acetate monomer.
- 19. The process of claim 15 wherein said polymer is a tetrapolymer represented by the formula: ##STR41## wherein A', R.sub.23, R.sub.24, R.sub.25, R.sub.26 and R.sub.27 are as defined in claim 15; wherein m", n" and r" have the same meaning as m, n and r, respectively; wherein p" is from about 20 to 96.9 mole %; wherein q" is greater than 0 and up to about 40 mole %, with the proviso that m"+n"+p"+q"=100 mole %; and wherein B represents a repeating unit derived from a member selected from the group consisting of acrylic and methacrylic acids, maleic acid, and alkali metal salts thereof.
- 20. The process of claim 19 wherein said tetrapolymer is hydrolyzed and is represented by the following formula: ##STR42## wherein R.sub.23, R.sub.24, R.sub.25, R.sub.26, R.sub.27, R.sub.28, R.sub.29, X, B, m", n", p", q" and r" are as defined in claim 19; and wherein z" is from about 0.1 to less than about 10 mole %, with the proviso that (m"-z")+n"+p"+q"+z"=100 mole %.
- 21. The process of claim 19 wherein said tetrapolymer comprises a polymer resulting from the polymerization of a water-in-oil monomer emulsion containing about 6-10 mole % of sodium-2-acrylamido-2-methylpropane sulfonate monomer, about 50-70 mole % of acrylamide monomer, about 1-5 mole % of vinyl acetate monomer and about 20-40 mole % of sodium acrylate monomer.
- 22. The process of claim 1 wherein said first initiator reaches a given half-life, t.sub.1/2, in hours, at a temperature less than the temperature at which said second initiator reaches that same half-life.
- 23. The process of claim 22 wherein the difference in temperature at which said first and second initiators reach a half-life is at least about 5.degree. C.
- 24. The process of claim 22 wherein the difference in temperature at which said first and second initiators reach a half-life is at least about 20.degree..
- 25. The process of claim 1 wherein the amount of polymer formed which is sufficient to provide for a shear-stable emulsion is up to about 5 weight percent of the total emulsion.
- 26. The process of claim 25 wherein the amount of polymer formed which is sufficient to provide for a shear-stable emulsion is from about 1 to about 5 weight percent of the total emulsion.
- 27. The process of claim 1 wherein said first polymerization initiator is one or more initiators selected from the group consisting of: 2,2'-azobis-(2-cyclopropylpropionitrile), 2,2'-azobis-(2,4-dimethyl-4-methoxyvaleronitrile), 2,2'-azobis-(1-cyclooctanenitrile), 1,1'-azobis-3-chlorocumene, 1,1'-azobis-4-chlorocumene, 2,2'-azobis-2-(4-tolyl)propane, phenyl-azo-triphenylmethane, 1,1'-azo-bis-1-(4-tolyl)cyclohexane, 3-tolyl-azo-triphenylmethane, isobutyryl peroxide, alpha-chloropropionyl-m-chlorobenzoyl peroxide, cyclopropane acetyl peroxide, benzoyl isobutyryl peroxide, m-chlorobenzoyl isobutyl peroxide, p-nitrobenzoyl isobutyryl peroxide, cyclopentane formyl peroxide, cyclohexane formyl peroxide, 2-iodobenzoyl-4-nitrobenzoyl peroxide, 2-nitrobenzoyl peroxide, benzoyl phenylacetyl peroxide, phenyl acetyl peroxide, benzoyl-[trans-2-(phenyl)vinyl]benzoyl peroxide, cis-4-tert-butylcyclohexane formyl peroxide, t-butyl-hydroperoxide/cobalt 2-ethyl hexanoate, t-butyl-hydroperoxide/cobalt stearate, dimethyl peroxalate, di-isopropyl peroxalate, di-(tert-butylperoxy)oxalate, di-tert-butyl-peroxalate, tert-butyl-2-(methylthio)perbenzoate, tert-butyl-2-(phenylthio)perbenzoate, tert-butyltriphenyl peracetate and p-toluenesulfonyl-p-tolysulfone.
- 28. The process of claim 1 wherein said second polymerization initiator is one or more initiators selected from the group consisting of: 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobis(isobutyronitrile), 2,2'-azobis-2,4,4-trimethylvaleronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis-2-ethylpropionitrile, 1,1'-azobis-1-cyclopentane nitrile, 2,2'-azobis-2,3-dimethylbutyronitrile, 2,2'-azobis-2-methylvaleronitrile, 2,2'-azobis-2-cyclobutylpropionitrile, 1,1'-azobis-1-cyclohexanenitrile, 2,2'-azobis-2-propylbutyronitrile, 2,2'-azobis-2,3,3-trimethylbutyronitrile, 2,2'-azobis-2-methylhexylonitrile, 2,2'-azobis-2-isopropylbutyronitrile, 1,1'-azobis-1-cycloheptanenitrile, 1,1'-azobis-1-(2-methylcyclohexane)-nitrile, 1,1'-azobis-1-cyclohexanecarbonitrile, 2,2'-azobis-2-isopropyl-3-methylbutyronitrile, 2,2'-azobis-2-benzylpropionitrile, 2,2'-azobis-2-(4-chlorobenzyl)propionitrile, 2,2'-azobis-2-(4-nitrobenzyl)propionitrile, 1,1'-azobis-1-cyclodecanenitrile, azo-bis-isobutyramidine, 2,2'-azobis-methyl-2-methylpropionate, azobis-(N,N'-dimethyleneisobutyramidine), azobis-(1-carbomethoxy-3-methylpropane), 2,2'-azobis-(ethyl-2-methylpropionate), 1,1'-azobis-1-chloro-1-phenylethane, 1,1'-azobis-1-chloro-1-(4-bromophenyl)ethane, 3,7'-diphenyll-1,2-diaza-1-cycloheptene, 1,1'-azobis-cumene, 3-bromophenyl-azo-triphenylmethane, 2,4-dinitrophenyl-azo-9-phenylfluorene, 1-hydroxybutyl-n-butyl peroxide, acetyl peroxide, propionyl peroxide, 2-iodopropionyl peroxide, butyryl peroxide, beta-allyloxypropionyl peroxide, benzoyl peroxide, 2-chlorobenzyl peroxide, 2,4-dichlorobenzoyl peroxide, cyclohexane acetyl peroxide, decanoyl peroxide, 4-benzylidenebutyryl peroxide, lauroyl peroxide, ethyl-tert-butyl peroxalate, tert-butyl perpivalate, tert-butyl phenylperacetate and potassium persulfate.
- 29. The process of claim 1 wherein said first initiator is 2,2'-azobis-2(2,4-dimethyl-4methoxyvaleronitrile or potassium persulfate and wherein said second initiator is 2,2'-azobis-(2,4-dimethylvaleronitrile).
Parent Case Info
This application is a continuation of prior U.S. application Ser. No. 474,420, filed Mar. 11, 1983, now abandoned.
US Referenced Citations (12)
Non-Patent Literature Citations (1)
Entry |
Frank Di Stefano, "Inverse Emulsion Polymerization of Acrylamide; A Mechanistic Study", Lehigh University Master's Thesis, Nov. 1981. |
Continuations (1)
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Number |
Date |
Country |
Parent |
474420 |
Mar 1983 |
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