Polyvinyl butyral ink formulation

DETAILED DESCRIPTION OFTHE INVENTION The polyvinyl butyral used in the present invention is prepared by the usual condensation of high molecular weight polyvinyl alcohol and n-butyralaldehyde.
The hydroxyl content, as recognized by those skilled in the art, varies according to the amount of n-butyraladehyde reacted with the polyvinyl alcohol.
The hydroxyl content of the polyvinyl butyral resin is calculated as polyvinyl alcohol and this hydroxyl content may be determined by the following procedure: 1.
000 gram of the polyvinyl butyral resin to be analyzed is dissolved in 25 milliliters of a solution containing, by weight, 88 parts pyridine and 12 parts acetic acid, and the solution placed in a bottle which is then sealed and heated in a boiling water bath for 11/2 hours and then cooled.
To the cooled solution there are added 20 drops of phenolphthalein indicator solution and 100 milliliters of 0.
3 normal sodium hydroxide solution, and the bottle sides washed with 100 milliliters of methyl isobutyl ketone.
The sample is then titrated with 0.
3 normal sodium hydroxide to the phenolphthalein end point.
A blank containing no resin is run under identical conditions and titrated as above, and the polyvinyl butyral resin hydroxyl content calculated as percent polyvinyl alcohol is determined as follows: Hydroxyl content (weight % polyvinyl alcohol)=1.
32[milliliters for blank-milliliters for sample] It has been discovered that polyvinyl butyral sheeting printed with the ink formulations of the present invention exhibits markedly reduced blocking combined with improved glass adhesion in the tinted gradient band when the hydroxyl content of the polyvinyl butyral used in printing ink is about from 29 to 35 weight % as determined by the above technique.
With respect to the polyvinyl butyral sheeting which is the substance for the printing ink, the hydroxyl content of the polyvinyl butyral used in the ink should be about from 5-50% greater than the hydroxyl content of the sheeting.
Below these minimal hydroxyl content percentages, the benefits of the present invention will be realized to a substantially lesser degree