Abstract: There is provided a composition comprising tannin containing hydroxyl groups which has been (a) chemically modified by reaction of at least one of said hydroxyl groups with at least one member selected from the group consisting of an esterification agent (e.g. acetic anhydride), etherification agent (e.g. dichloromethane or quaternary organic amine such as N-(3-chloro-2-hydroxypropyl) trimethyl ammonium chloride) to form the corresponding ester, or ether, through said hydroxyl group, and (b) derivatized. The chemically modified tannin is derivatized by reaction with aldehyhde (e.g. formaldehyde), or aldehyde and at least one member selected from the group consisting of ammonia and organic amine containing at least one primary or secondary nitrogen (e.g. cyclohexyl amine); said derivatized tannin being water soluble or dispersable at a pH below 7 and water insoluble at a pH above 7.

Abstract: There is provided a composition comprising tannin containing hydroxyl groups which has been (a) chemically modified by reaction of at least one of said hydroxyl groups with at least one member selected from the group consisting of an esterification agent (e.g. acetic anhydride), etherification agent (e.g. dichloromethane or quaternary organic amine such as N-(3-chloro-2-hydroxypropyl) trimethyl ammonium chloride) to form the corresponding ester, or ether, through said hydroxyl group, and (b) derivatized. The chemically modified tannin is derivatized by reaction with aldehyhde (e.g. formaldehyde), or aldehyde and at least one member selected from the group consisting of ammonia and organic amine containing at least one primary or secondary nitrogen (e.g. cyclohexyl amine); said derivatized tannin being water soluble or dispersable at a pH below 7 and water insoluble at a pH above 7.

Abstract: There is provided a composition comprising tannin containing hydroxyl groups which has been (a) chemically modified by reaction of at least one of said hydroxyl groups with at least one member selected from the group consisting of an esterification agent (e.g. acetic anhydride), etherification agent (e.g. dichloromethane or quaternary organic amine such as N-(3-chloro-2-hydroxypropyl) trimethyl ammonium chloride) to form the corresponding ester, or ether, through said hydroxyl group, and (b) derivatized. The chemically modified tannin is derivatized by reaction with aldehyhde (e.g. formaldehyde), or aldehyde and at least one member selected from the group consisting of ammonia and organic amine containing at least one primary or secondary nitrogen (e.g. cyclohexyl amine); said derivatized tannin being water soluble or dispersable at a pH below 7 and water insoluble at a pH above 7.