In printing ink industry, Gum Rosin is mainly used as color carrier of the ink and to increase its adhesion to paper. Without gum rosin in the ink, the presswork will be blurred. In China, printing ink typically contains about 7% of rosin.
In hectograph ink, rosin is often modified by phenol aldehyde to fulfill the requirements that the soften point be between 160 and 175 centigrade and the acid value below 20. In gravure ink, metal resinate is typically used with the properties that the soften point be between 125 and 135 centigrade and the acid value below 95.
If we substitute ordinary rosin with polymerized rosin, various sorts of special ink can be produced, such as gasoline printing ink to replace toluene ink, coating ink to replace Cuban gum, hectograph ink to replace bisphenol resin, etc. This will inaugurate many new areas of usage for gum rosin.