Patent
Polymer flocculants with improved dewatering characteristics
| العنوان: | Polymer flocculants with improved dewatering characteristics |
|---|---|
| Patent Number: | 6,294,622 |
| تاريخ النشر: | September 25, 2001 |
| Appl. No: | 09/406,031 |
| Application Filed: | September 27, 1999 |
| مستخلص: | A high molecular weight water soluble acrylamide based polymer having improved flocculating properties is provided. The polymer is prepared by a process, in which a small quantity of a chain branching agent is added to the polymerization reaction mixture continuously or semi-continuously while the monomers are polymerized. The polymer is useful in solid/liquid separations such as flocculants and coagulants in waste water treatment applications, and as thickening agents. |
| Inventors: | Barajas, Jose Hernandez (Rennes, CHX); Wandrey, Christine (Ecublens, CHX); Hunkeler, David (St. Sulpice, CHX) |
| Assignees: | Ecole Polytechnique Federale de Lausanne (EPFL) (CHX) |
| Claim: | That which is claimed |
| Claim: | 1. A process for preparing a water soluble acrylic based polymer, comprising the steps of |
| Claim: | providing a polymerization reaction mixture comprising one or more polymerizable acrylic monomers; and |
| Claim: | polymerizing said acrylic monomers while adding to the reaction mixture a chain branching agent continuously or semi-continuously. |
| Claim: | 2. The process of claim 1, wherein said one or more acrylic monomers are selected from the group consisting of acrylamide, methacrylamide, N-vinyl methyl acetamide, N-vinyl methyl formamide, dialkylaminoalkylmethacrylamide, sulphomethylated acrylamide, vinyl acetate, vinyl pyrrolidone, methacrylic esters, styrene, acrylonitrile, methacrylic acid, itaconic acid, acrylamido methyl propane sulphonic acid, allylsulphonate, sodium vinyl sulphonate, sodium acrylate, diallyldimethylammonium chloride, methacrylamidepropyl trimethylammonium chloride, dialkylaminoalkyl methacrylate, dialkylaminoalkyl acrylate, dialkylaminoalkyl acrylate methyl chloride, and quaternaries or acid salts thereof. |
| Claim: | 3. The process of claim 1, wherein said chain branching agent is N, N-methylenebisacrylamide. |
| Claim: | 4. The process of claim 1, wherein the chain branching agent is added to the reaction mixture continuously in a constant manner. |
| Claim: | 5. The process of claim 1, wherein the chain branching agent is added to the reaction mixture semi-continuously in a constant manner. |
| Claim: | 6. A process for preparing a water soluble acrylamide based polymer, comprising the steps of |
| Claim: | providing a polymerization reaction mixture comprising one or more polymerizable acrylamide monomers; and |
| Claim: | polymerizing said acrylamide monomers while adding to the reaction mixture a chain branching agent continuously or semi-continuously. |
| Claim: | 7. The process of claim 6, wherein said chain branching agent is added at a total amount of from about 1 ppm to about 5.times.10.sup.4 ppm based on said reaction mixture. |
| Claim: | 8. The process of claim 6, wherein said acrylamide monomers are selected from the group consisting of acrylamide, methacrylamide, N-vinyl methyl acetamide, N-vinyl methyl formamide, dialkylaminoalkylmethacrylamide, sulphomethylated acrylamide. |
| Claim: | 9. The process of claim 6, wherein said reaction mixture further comprises a monomer selected from the group consisting of vinyl acetate, vinyl pyrrolidone, methacrylic esters, styrene, acrylonitrile, acrylic acid, methacrylic acid, itaconic acid, acrylamido methyl propane sulphonic acid, allylsulphonate, sodium vinyl sulphonate, sodium acrylate, diallyldimethylammonium chloride, methacrylamidepropyl trimethylammonium chloride, dialkylaminoalkyl methacrylate, dialkylaminoalkyl acrylate, dialkylaminoalkyl acrylate methyl chloride, and quaternaries or acid salts thereof. |
| Claim: | 10. The process of claim 6, wherein N, N-methylenebisacrylamide is added as the chain branching agent at a total amount of from about 1 ppm to about 100 ppm based on monomers. |
| Claim: | 11. The process of claim 6, wherein said reaction mixture is in a form of inverse-emulsion. |
| Claim: | 12. The process of claim 6, wherein said one or more monomers include acrylamide and dimethylaminoethylacrylate (as acid salt or quaternary salt). |
| Claim: | 13. The process of claim 6, wherein said chain branching agent is added continuously in a constant manner. |
| Claim: | 14. The process of claim 6, wherein said chain branching agent is added semi-continuously in a constant manner. |
| Claim: | 15. A process for preparing a water soluble acrylamide based polymer, comprising the steps of |
| Claim: | providing a polymerization reaction mixture in an inverse-emulsion comprising acrylamide and dimethylaminoethylacrylate (as acid salt or quaternary salt) as polymerizable monomers, with at least 30% by weight of the monomers being said dimethylaminoethylacrylate (as acid salt or quaternary salt); and |
| Claim: | polymerizing said monomers while adding to the reaction mixture N, N-methylenebisacrylamide as a chain branching agent, in a constant manner, at a total amount of from about 1 ppm to about 100 ppm based on total monomers. |
| Claim: | 16. A process for preparing a water soluble acrylic based polymer, comprising the steps of |
| Claim: | (a) providing a polymerization reaction mixture comprising one or more polymerizable acrylic monomers; and |
| Claim: | (b) polymerizing said acrylic monomers while adding to the reaction mixture a chain branching agent either continuously or stepwise as a function of reaction time |
| Claim: | wherein said water soluble acrylic based polymer exhibits an intrinsic viscosity that is at least about 10% higher than the intrinsic viscosity achieved by performing the polymerization step (b) with batch addition of chain branching agent instead of continuous or stepwise addition. |
| Claim: | 17. A process for preparing a water soluble acrylic based polymer, comprising the steps of |
| Claim: | polymerizing said acrylic monomers while adding to the reaction mixture a chain branching agent either continuously or stepwise as a function of reaction time |
| Claim: | wherein said water soluble acrylic based polymer exhibits a an intrinsic viscosity of greater than about 4 dl/g in 1M NaCl at 25.degree. C. and a sedimentation coefficient of the soluble portion of greater than or equal to 6.17 Svedberg in 0.05 M NaCl at 20.degree. C. |
| Claim: | 18. A process for preparing a water soluble acrylic based polymer, comprising the steps of |
| Claim: | wherein said water soluble acrylic based polymer exhibits an intrinsic viscosity of greater than about 4 dl/g in 1M NaCl at 25.degree. C. and an association to chain branching agent ratio of less than 2.5 as measured in 0.05 M NaCl at 20.degree. C. |
| Claim: | 19. A process for preparing a water soluble acrylic based polymer, comprising the steps of |
| Claim: | wherein said adding further comprises adding said chain branching agent at a constant rate of between about 0.1 to about 20 weight % of the total amount of chain branching agent per hour during polymerization. |
| Current U.S. Class: | 526/78; 526/87; 5262/922 |
| Current International Class: | C08F 216 |
| Patent References Cited: | 4217262 August 1980 Coscia et al. 4720346 January 1988 Flesher et al. 4759856 July 1988 Farrar et al. 4956399 September 1990 Kozakiewicz et al. 5037863 August 1991 Kozakiewicz et al. 5110864 May 1992 Robinson et al. 5354480 October 1994 Robinson et al. 5413720 May 1995 Miller 5543058 August 1996 Miller 5597490 January 1997 Chung et al. 5601725 February 1997 Chung et al. 5643461 July 1997 Neff et al. 5652292 July 1997 Stanley, Jr. 5879564 March 1999 Farinato 5945494 August 1999 Neff et al. |
| Other References: | A Concise Review of the Influence of Synthesis and Technological Factors on the Structure and Properties of Polyacrylamides, D. Hunkeler et al., Industrial Water Soluble Polymers, 1996, pp. 10-27. |
| Primary Examiner: | Wu, David W. |
| Assistant Examiner: | Cheung, William K |
| Attorney, Agent or Firm: | Alston & Bird LLP |
| رقم الانضمام: | edspgr.06294622 |
| قاعدة البيانات: | USPTO Patent Grants |
| الوصف غير متاح. |