Claims
- 1. Solvent-free, fine white powders of a copolymer of maleic anhydride and a C1-C4 alkyl vinyl ether substantially free of poly(alkylvinyl ether) homopolymer.
- 2. The copolymer of claim 1 which is free of said homopolymer to <1 molar %, as determined by NMR analysis.
- 3. A solvent-free process for making fine white powders of a copolymer of maleic anhydride and an alkyl vinyl ether substantially free of poly(alkyl vinyl ether), by copolymerization of maleic anhydride (MAN) and excess alkyl vinyl ether (AVE) monomers and a free radical initiator to promote radical copolymerization of said monomers, which comprises including in the reaction mixture an effective amount of water as a suppressor agent sufficient to preclude cationic homopolymerization of alkyl vinyl ether monomer into poly(alkyl vinyl ether) homopolymer, said amount being about 500 to about 5000 ppm.
- 4. A solvent-free process according to claim 3 wherein the free radical initiator is present in an amount of 0.01 to 0.2% by weight based on copolymer obtained.
- 5. A solvent-free process according to claim 3 which is run at 10-40% solids.
- 6. A solvent-free process according to claim 3 wherein the alkyl vinyl ether:maleic anhydride mole ratio is at least 3.
- 7. A solvent-free process according to claim 6 in which said ratio is about about 25 to about 6.
- 8. A solvent-free process according to claim 3 in which molten maleic anhydride is fed into the precharged reaction mixture of excess alkyl vinyl ether, free radical initiator and suppressor agent during a predetermined period of time.
- 9. A solvent-free process according to claim 3 in which the polymerization product is dried under vacuum at 40 to 100° C. to remove any traces of alkyl vinyl ether and any remaining suppressor agent.
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
A solvent-free process for making copolymers of maleic anhydride and an alkyl vinyl ether is described in continuation-in-part U.S. patent application Ser. No. 08/942,830, filed Oct. 2, 1997, now U.S. Pat. No. 5,939,506.
US Referenced Citations (10)
Non-Patent Literature Citations (1)
Entry |
“Polymer Handbook”, 2-d edition, J. Brandrup, J. Willey & Sons, NY, pp. 11-391-98, 1974. |
Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
08/942830 |
Oct 1997 |
US |
Child |
09/270176 |
|
US |