Synthesis And Application Of Zeolite 4A In Friction Modifier Of Toothpaste

Toothpaste, the indispensable commodity of people's daily life, is made up of many kinds of components. As one of these components, friction modifier plays an important function for removing the dirt and colored substance attached to the surface of tooth. CaCO3 SiO₂ CaHPO4 · 2H2O, Al₂O3 etc. are usually used as friction modifier, but they have respective merits and shortcomings in actual use. With the improvement of people's life, toothpaste with high quality was required. Thus the better friction modifier was required. The new friction modifier should not only has friction effect, but satisfies the requirement of fluorine content, moreover, it is expected to absorb some additives such as medicine ingredients so as to get multiple effects. Molecular sieve 4A has perfectly physical and chemical properties. It is a kind of good carrier with symmetrical porous structure and fine chemical stability, and it owns suitable friction value at the same time.Molecular sieve 4A was hydrothermally synthesized with sodium silicate, aluminum hydroxide and sodium hydroxide and its size was controlled by adding crystallization director. Optimal synthesis condition is that mole ratio is 1A12O3 : 1.9SiO2 : 3.04Na2O : 121.6H2O, temperature is 90℃; crystallization time is 1.5h, and the amount of crystallization director is 5% of material in mole ratio. The average diameter of sample is 1.4 m .In order to decrease the cost, molecular sieve 4A with uniform particles was synthesized with Suzhou kaolin by hydrothermal method. The influence of some factors was investigated, then the synthesis condition was modulated and optimized. Under the optimal condition, molecular sieve 4A with uniform particles was synthesized and the average diameter of sample is 2.3 m. Molecular sieve 4A synthesized by two different materials were characterized by X-ray diffractometer, scanning electron microscopy and laser granularity meter etc.The absorptive property of molecular sieve 4A to fluorine ion was measured by ion selective electrode method. The result indicates that there is a fine compatibility between molecular sieve 4A and fluorine ion. Some factors such as concentration of fluorine ion in solution, amount of molecular sieve 4A used, size of molecular sieve 4A etc. affect the absorption of fluorine ion on molecular sieve 4A, and the concentration of fluorine ion in solution affects the result most dramatically. Absorption amount of fluorine on molecular sieve 4A can reach 8000mg/kg(molecular sieve),which exceed the national standard quantity (1500mg/kg) in the toothpaste. Molecular sieve 4A can absorb fluorine ion in expected amount by regulating the experiment conditions, which can satisfy the requirement of fluorine content in toothpaste.The compatibility of molecular sieve 4A and essence was measured by the Weight Law. The result shows molecular sieve 4A has very good absorptive ability to essence, and amount of molecular sieve 4A, amount of essence etc. have impact on absorptive results. Better condition for absorptionwas acquired from orthogonal test method. Through a series of experiments, it can be found that molecular sieve 4A is capable of absorbing and releasing essence in controlling.Molecular sieve 4A with uniform particles was synthesized by different material. The results show that both of the products achieve the requirement of friction modifier. Molecular sieve 4A synthesized by Suzhou kaolin cut down the cost effectively. Therefore, as a new-type friction modifier in toothpaste industry, molecular sieve 4A will have broad prospects in application.