Research On Modification Of Nano-CaCO₃ Used In Ink By Compound Modification Agent

The functional material nanometer calcium carbonate (abbreviated to nano-CaCO3), industrialized with large volume production and low price, can be applied widely to rubber, plastics, coatings, printing ink, paper-making manufacture. However, its lagged applicable technology has seriously bindered the development of related industries in our country, generating a great gap to Japan and the United States especially in its application to ink. In order to improve its the performance and grades, we carried on several experiments on the existing with nano-CaCO3 modification technology and discovered the compound modification agent KW-1.Two optimization tests are made on the CaCO3 cube with different modifiers, including traditional stearic acid modifier and the new modifier. Firstly, we applied the agent stearic acid to tset the surface modification on cube nano-CaCO3, getting the best modification conditions:modifier dosage 6%, modified time 30min, modified temperature 90℃, initial slurry concentration 4%, stirring speed 1900 r/min, drying temperature80℃, drying time 10h, the effect of this product obtained under such condition seemed to be ordinary as follows:the oil absorption value was 54.9 gDOP/100gCaCO3, the fluidity was 15.5mm, the glossiness was 7.2GS, the transparence was secondary. Secondly we used the compound modification agent KW-1, getting the best modification conditions:modifier dosage 4%, modified time 30min, modified temperature 70℃, initial slurry concentration 4%, stirring speed 1900 r/min, drying temperature80℃, drying time 10h. The optimum product obtained was tested with features: the oil absorption value was 42.5 gDOP/100gCaCO3, the fluidity was 30.4mm, the glossiness was 17.8GS, the transparence was primary. Compared to the traditional modifier, KW-1 has much better effect than single stearic acid.Also this test about surface modification was given to chain nano-CaCO3 with KW-1 under the same conditions to the cube nano-CaCO3. After the test for oil absorption value, fluidity, glossiness, transparence we found that the cube nano-CaCO3 used in the ink made better faction than the chain nano-CaCO3, showing the better ink filler is cube nano-CaCO3. In addition, we analysed the substsncial mechanism on how the modifier acts. Analysed by SEM, we observed the treated CaCO3 particles become bigger, interpreted that nano-CaCO3 was wrapped up by modifier. Through IR, TG-DSC detection we can found in the modification process there happened physical adsorption and chemical adsorption, while the latter one outweighs, performing as follows:carboxylic group and Ca2+ react to form Carboxylic acid calcium, the amino-group from modifier and printing ink oil have cross-linking reaction. Thus the better the dispersion is in the ink, the better the glossiness and transparence are, so the dispersion of the nano-CaCO3 in the ink is of great significance.