Claims
- 1. Amphoteric polymer derived from:
- (a) 20 to 90 mol percent of acrylic acid units,
- (b) 10 to 30 mol percent of N,N-dimethylaminoethyl methacrylate or N,N-diethylaminoethyl methacrylate units, and
- (c) 0 to 70 mole percent of units from one or more members of the group consisting of C.sub.1-8 alkyl acrylate, C.sub.1-8 alkyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate and 2-hydroxypropyl methacrylate; said polymer prepared by copolymerizing (a), (b) and (c), in solution, in the presence of a strong acid selected from the group consisting of nitric acid, sulfuric acid and hydrochloric acid, in a quantity sufficient to protonate the amine group of (b),
- the polymer characterized further by having (i) a molar ratio of (a) to (b) of at least 2 to 1, and (ii) substantially no betaine-type contaminant.
- 2. Polymer of claim 1 in which the molar ratio of (a) to (b) is at least 2.5 to 1.
- 3. Polymer of claim 1 wherein the degree of polymerization is about 50 to 300.
- 4. Polymer of claim 1 wherein the degree of polymerization is about 50 to 300.
Parent Case Info
This is a division of U.S. application Ser. No. 176,806, filed Apr. 1, 1988 now abandoned, which was a divisional U.S. application Ser. No. 377,373 filed May 12, 1982 now U.S. Pat. No. 4,943,888.
US Referenced Citations (19)
Foreign Referenced Citations (1)
Number |
Date |
Country |
889760 |
Feb 1962 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Merle et al. Synthetic Polyampholytes. Z. Sequence Distribution in Methacrylic Acid. (Dimethylamino)ethyl Methacrylate Copolymers by .sup.13 C NMR Spectroscopy, Macromolecules 1982, 15, 360-365. |
Divisions (2)
|
Number |
Date |
Country |
Parent |
176806 |
Apr 1988 |
|
Parent |
377373 |
May 1982 |
|