| 摘要 |
PURPOSE: To obtain a surface coating agent more excellent in paper strength properties such as a surface strength and a Z-directional tensile strength when coating on a paper than usual coating agents by including (meth)acrylamide and a specific polymer. CONSTITUTION: A (meth)acrylamide is mixed with a vinyl compound expressed by the formula (R1 is H or a 1-3C lower alkyl; (n) is 1-5) or its salt as monomers, and further, a crosslinked vinyl monomer is added thereto, then the mixture is subjected to radical polymerization to obtain the objective surface coating agent for paper, composed of an aqueous solution of an acrylamide- based polymer having a high molecular weight and low viscosity without gelling in spite of a high concentration. This coating agent preferably has a viscosity of <=5×10<4> cps at 25 deg.C and a weight-average molecular weight of 50×10<4> to 1000×10<4> in a range of polymer concentration of 22-60%. The coating agent exhibits an excellent surface strength-improving effect superior to that of the usual agents when applying to paper.
|
