Resinas Stiren Mal Papel

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APPLICATION BULLETIN
Styrene Maleic Anhydride Imide Resin (SMAI): A Novel Cationic Additive in Paper Coating for Ink-Jet Printing
Abstract A good image reproduction in ink-jet printing requires the dye of the ink to be retained and chemically fixed on the surface of the coated sheet. To achieve this, usually a cationic additive is added to the paper coating formulations. The most commonlyused cationic additive that fixes the dye is poly-DADMAC. Though considered to be a good dye-fixing agent, polyDADMAC has a few inherent characteristics that cause drastic increases in the viscosity and rigidity of the coating color that can lead to poor runnability and brittle coating structure. The main objective of this work is to study the interactions of SMAI, a multifunctional resin, in aprecipitated calcium carbonate based paper coating and its effects on print image quality, water fastness and surface gloss. The mean grey value, image area and perimeter were used as a direct measure of the print density and print sharpness. The evaluated parameters were superior to those attained with a conventional cationic additive. The study demonstrates the potential of developing SMAI as anefficient and commercially viable cationic additive in paper coating for ink-jet printing. Introduction Ink-jet printing has become a prominent method to reproduce high quality digital images both at home and the office. The quality of the image reproduced depends profoundly on the structure and composition of the coating, and to a good extent on the ink and the resolution attained by the printer.The ink-jet ink typically contains functional groups like sulphonic or carboxylic acids that make them water-soluble and cellulose-loving(1). Hence, it is critical that the coated paper be able to assist the drying of the ink before the ink drop penetrates deeply into the paper, to fix the dye chemically and maintain it physically at the surface of the paper. This mechanism of dye fixation is animportant characteristic of a coating for inkjet printing. It is a key to several important components of print qualities like high print density, high print sharpness, high water fastness and low image printthrough. Two different approaches can be made to promote the dye fixing mechanism. Uncoated paper is sized to balance lateral ink spreading and z- direction penetration. However, a higher printquality can be obtained through pigmented coatings. The dye segregation property of a coating can be achieved by chemical fixation and/or by size exclusion. Chemical fixation of the dye is obtained by introducing cationic sites in the coating through the use of appropriate cationic additives. The dye can also remain at the surface of the paper by the filtering out of the dye molecules by thepigment. A coating that promotes the segregation of the dye molecules in its upper layer will be very effective in attaining a bright quality print. Experimental Materials In this work, precipitated calcium carbonate (PCC) was used as the pigment. PCC is an emerging commercial alternative to silica. Partially hydrolyzed poly(vinyl alcohol) (PVOH) was used as the binder and SMAI as cationic additive.The SMAI resins used in this study have styrene to maleic anhydride ratios of 1:1, 2:1, and 3:1 and are named SMA1000I, SMA2000I and SMA3000I respectively.

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4967 09/04

Fig. 1. Styrene Maelic Anhydride Imide resin
C H 3C O O H 3C N 1H (C H 2 ) 3 O C CH2 CH CH N2 CCH O CH3

in a controlled temperature and humidity room at 25°C and 50% RH for 24 hours. The conditioned sheets were cut into 4 inch sections and were calendared using a laboratory calendar at a line load 300 kN/m and at 100°C. These calendared sheets were once again placed in the conditioning room for 24 hours prior to printing for print quality analysis. Print Quality Analysis A Canon BJC –...