Cast Coated Film Transfer Surface Sizing

Paper produced by traditional coating process, must be calendered or super calendered to get high gloss and smoothness, but other properties could be affected, for example, bulkiness, tensile strength, ink obsorptivity will be decreased. So we wish that the paper can get high gloss and smoothness, but needn't be calendered or super calendered. The experiment process as follows: First, coating color is applied onto the Teflon plate with the applicator rod. After drying for some time, the paper is put onto the coating film and pressed. Then dry and part them. Main results have been obtained as follows:Teflon (PTFE)plate and organosillcon release paper are both with good release properties, but the properties of Teflon plate is better than release paper.Polyvinyl alcohol (PVA)and oxidized starch are both with good film forming properties, oxidized starch has a higher gloss than PVA, but other properties is lower. Considering the cost and the paper physical properties, these two sizing agent are mixed in propertion. At the ratio of 7:3 and low coating weight(5g/m~2),the coating papers gloss can reach78%,bright is 244s,breaking length is 4.46Km and the IGT surface strength is 4.36m/s,but ink obsorptivity is not satisfied by recent printing.Many factors can affect the paper gloss, smoothness, opacity, breaking strength and surface strength including sizing amount, drying time of the coating film, drying time after binding of the base paper and the coating film, pressure of calendaring and temperature of the calender roll.Drying during the press, adding calcium carbonate, silica and glass fiber can improve the ink obsorptivity. But at the same time, all kinds of the physical properties of the paper would be affected in some degree.There are relation between the viscosity of the sizing and even film forming of the sizing on the Teflon plate. Strength of the film , bonding between the base paper and the film , surface tension of the board .constitute of size and pressure affect the transfer result .The properties of the base paper affect gloss and smoothness little of the paper.Paper made by adding PCC(120%) has relative properties with north America 5~# LWC ,besides higher density. Paper made by the method of drying during the press has many good properties than the criteria of one-side offset paper in china including gloss, smoothness, surface strength, and so on.