The Preparation And Application Of Surface Size Agent Applied In Uncoated Ink-jet Paper

The preparation of surface sizing for uncoated ink-jet paper is discussed in this paper. In the paper the effects of using the polyvinyl formal as surface sizing agent which is specially used for uncoated int-jet paper were studied. Aiming to improve surface strength viscosity ink absorbable ability and water resistance polyvinyl formal was synthesized. Then the sizing agent was prepared by melting method. Polyvinyl formal oxidized starch and gelatin were chosen as research objectives in this dissertation. As a result main researches were carried out as follows:1. The modification of PVADeepening study was carried out of the synthesis of Polyvinyl formal, its reaction law was summed up and optimum technological conditions were presented. In the process of synthesis, the main factors included reaction temperature of the first step and that of the second step etc. Optimum reaction conditions were obtained. The optimum reaction conditions were found as follows (for 200 grams of 10% solution of polyvinyl alcohol):a. The amount of formaldehyde: 10 grams;b. Retains the pH scale of 1.5 in reaction system;c. Reaction temperature of first step is 70℃; reaction temperature of second step is 60℃;d. Reaction time duration is about 60 minutes;2. Free formaldehyde contentThis technology can decrease the amount of dissociate formaldehyde by adding urea. The fitting quality ratio for urea / formaldehyde was 1:2.3. The sizing agent which is specially used for uncoated int-jet paper was melt with other sizing agents. It was found that the fitting volume ratio for melting PVF/ oxidized starch /gelatin was 6:2:1.The effects of sizing were discussed too the results were as follows: chemical contents was 9%, sizing dosages were 6.2g/m2, sizing temperature was 50℃, drying temperature was 105℃and drying time was 1.5min.4,Mechanism of improvement in surface strength and printability was discussed.