Paper filler refers to the addition of some basic water-insoluble solid particles in the pulp to improve the paper opacity, brightness, smoothness, print adaptability, etc, in paper making process.
1. Change the paper optical properties. By changing the refractive index and light scattering coefficient to increase the paper opacity and brightness and prevent the strike-through.
2. Improve the paper surface properties and printability. Filling can improve the paper smoothness and evenness, improve the paper absorption and ink absorption, and reduce the paper water retention and deformation.
3. Give the paper some special features. Such as the cigarette paper add calcium carbonate, improve breathability, adjust the burning rate. Conductive paper is added with carbon black to obtain conductivity.
4. Save fiber raw materials, reduce production costs. The price of the filler is less than fiber raw materials, so filling can greatly reduce the amount of fiber, and greatly reduce production costs. Of course, the amount of filler can not be too large, otherwise it will greatly reduce the paper strength index.
5. The filler has a large specific surface area, can absorb resin, so that the resin in the pulp does not condense into large particles, thus helping to overcome the resin barrier.
Also filling has a certain adverse effect: The filled paper, because the filler dispersed in the fiber, so that the paper structure is loose and porous, reducing the fiber contacting and hydrogen bonding, the paper physical strength decreased; Fill make the phenomenon increasing of paper loss powder when printing; Fill will reduce the paper sizing, especially alkaline fillers effect on the acidic sizing more harmful.
