Anionic cellulose nitrate derivatives and aqueous dispersions thereof
View Patent ↗An anionic cellulose nitrate derivative is described, which has: (i) a degree of acid group substitution (DS (acid)) in the range of 0.01 to 0.2; and (ii) a nitrogen content of 10.7 wt. % to 12.3 wt. %, based on the weight of cellulose nitrate derivative. The anionic cellulose nitrate derivative is prepared by a process which includes esterifying cellulose nitrate feed material with at least one dicarboxylic acid anhydride (e.g., maleic anhydride). Aqueous dispersions according to the present invention include: (a) at least on anionic cellulose nitrate derivative according to the present invention; and (b) at least one base.
1. An anionic cellulose nitrate derivative prepared by a process comprising esterifying cellulose nitrate with at least one dicarboxylic acid anhydride,
wherein said anionic cellulose nitrate derivative has,
(i) a degree of acid group substitution (DS (acid)) in the range of 0.01 to 0.2, and
(ii) a nitrogen content of 10.7 wt. % to 12.3 wt. %, based on the weight of cellulose nitrate derivative.
2. The anionic cellulose nitrate derivative of claim 1 wherein said dicarboxylic acid anhydride is succinic anhydride.
3. The anionic cellulose nitrate derivative of claim 1 wherein said dicarboxylic acid anhydride is maleic anhydride.
4. The anionic cellulose nitrate derivative of claim 1 wherein said anionic cellulose nitrate derivative has a nitrogen content of 12.0 wt. % to 12.3 wt. %, based on the weight of cellulose nitrate derivative.
5. A process of preparing an anionic cellulose nitrate derivative comprising esterifying cellulose nitrate with at least one dicarboxylic acid anhydride,
wherein said anionic cellulose nitrate derivative has,
(i) a degree of acid group substitution (DS (acid)) in the range of 0.01 to 0.2, and
(ii) a nitrogen content of 10.7 wt. % to 12.3 wt. %, based on the weight of cellulose nitrate derivative.
6. The process of claim 5 wherein the esterification reaction is performed in a melt of said dicarboxylic acid anhydride.
7. An aqueous dispersion comprising:
(a) at least one anionic cellulose nitrate derivative; and
(b) at least one base,
wherein said anionic cellulose nitrate derivative is prepared by a process comprising esterifying cellulose nitrate with at least one dicarboxylic acid anhydride, and further wherein said anionic cellulose nitrate derivative has,
(i) a degree of acid group substitution (DS (acid)) in the range of 0.01 to 0.2, and
(ii) a nitrogen content of 10.7 wt. % to 12.3 wt. %, based on the weight of cellulose nitrate derivative.
8. The aqueous dispersion of claim 7 wherein the base is selected from the group consisting of (i) alkali metal compounds, (ii) ammonia, (iii) organic amines represented by the following general formula,
NR 1 R 2 R 3
wherein R 1 , R 2 and R 3 are each independently selected from the group consisting of hydrogen, aminoalkyl, alkyl, aryl and alkenyl radicals, provided that at least one of R 1 , R 2 and R 3 is other than hydrogen, and (iv) combinations of at least two of (i), (ii) and (iii).
9. A process of preparing the aqueous dispersion of claim 7 comprising dispersing said anionic cellulose nitrate derivative in a medium selected from the group consisting of water and an aqueous system.
10. The process of claim 9 wherein said aqueous system is selected from the group consisting of alkyd dispersions, acrylate dispersions, polyurethane dispersions and combinations thereof.