Study on modification of calcium carbonate for paper filler

Abstract

Using silane coupling agent and ammonium zirconium carbonate to modify heavy calcium carbonate separately. Experiments show that using modified calcium carbonate as a filler made of significantly higher than filling in terms of the physical strength of paper. Under 40 ° SR condition, after 1% ammonium zirconium carbonate complex of 4% oxidized starch modified calcium carbonate which works best, to which tensile index up 74.5 N.m / g, while the filling GCC is 54.9 N .m / g. Through the ash of calcium carbonate filler finding that retention of modified is higher than unmodified ,from 31.35 % to 45.94%. Introduction The advantages of calcium carbonate[1] are high brightness[2], fine particles, and improving the opacity of paper significantly. In addition ,fast ink absorption of calcium carbonate, can effectively promote drying of the printing ink, paper with a relatively soft, dense, shiny. The best advantages of calcium carbonate is that can be controlled combustion of the paper, and can effectively improve the air permeability of the paper and the opacity. Therefore , calcium carbonate is the ideal papermaking filler [3]. However, calcium carbonate is an alkaline filler having relatively poor chemical stability, in acidic conditions readily decompose into carbon dioxide gas and produce the bubble, and then the pH of the slurry is increased, destructs the effect of sizing, and makes the papermaking difficult. Therefore, calcium carbonate as a filler paper, the current multi-use neutral sizing or no sizing of paper and thin printing paper. Calcium carbonate fillers for papermaking --There are two types of ground calcium carbonate (GCC) and precipitated calcium carbonate (PCC), ground calcium carbonate particle shape is irregular, but the surface is very rough, so it needs to be modified. Activity of calcium carbonate, also known as modified calcium carbonate[4], surface treated calcium carbonate, calcium abbreviation live, is obtained from the GCC light calcium or surface modified with a surface modifier[5]. The modified calcium carbonate which is small particle size, low oil absorption and good dispersion, more important is having a reinforcement, but also socalled active, is usually referred to activity of calcium carbonate. The surface modifying agents commonly used of heavy calcium carbonate[6] are mainly coupling agents[7,8], fatty acids and salts, the water-soluble polymer and organic oligomer, etc. There are a silane coupling agent[9], titanate coupling agent and aluminum coupling agent and so on. Fatty acids and their salts are mainly stearate[10], sodium stearate, calcium stearate, zinc stearate, etc. Water-soluble polymers can be divided into natural water-soluble polymers, semisynthetic water-soluble polymers and synthetic water-soluble polymers, Calcium carbonate is used primarily in aqueous systems to improve dispersion stability and compatibility. 4th International Conference on Machinery, Materials and Computing Technology (ICMMCT 2016) © 2016. The authors Published by Atlantis Press 395 Nowadays the papermaking industry is being plagued by a series of serious environmental problems. Since the world's forest area is gradually narrowing, leading wood fiber pulp prices rising and insufficient supply. What’s more, the cost of processing waste generated in the paper process is also significantly improved. Finally, the paper added other energy prices also rose sharply. Therefore, the paper industry is currently faced with two choices, either to pay the high cost or reduce the quantity and quality of the fiber, but will lead to lower quality paper. There is no effect on the strength properties of the paper that the unmodified filler directly into the paper feed system through using the traditional filling method. The strength properties of the paper is often also decline. And the study to improve the negative phenomena is very important. At present, the calcium carbonate filler has become an important development direction of the paper filler. Adding calcium carbonate filled paper, the strength performance is critical, and largely determines the application properties of the paper. In recent years, the international research modified calcium carbonate filler for paper activity, there have been a series of research reports. Experimental Materials and Chemicals GCC、Canadian softwood bleached pulp、 silane coupling agent、Ammonium zirconium carbonate、Oxidized starch、Neutral dispersant、CPAM Analytical Methods Experimental Method Calcium Carbonate Modified Selected a modifier : silane coupling agent and zirconium ammonium carbonate modified heavy calcium carbonate, and filling into the pulp, the physical properties of the paper was detected, then determined the final condition. Pulp processing and Papermaking Used Wali beater ease softwood pulp board, then, refining with PFI refiner. Made freeness:25°SR,30°SR,35°SR,40°SR,45°SR.Last , Papermaking . Test results Effect of modified calcium carbonate on the sheet properties. Table1 modifier species