The Application of Modified Molecular Sieve Powder in Polyurethane systems

Molecular sieves are commonly used and highly efficient absorbents for water and carbon dioxide. It is precisely because molecular sieves have the dual functions of dehydration and carbon dioxide absorption that they are relatively ideal inhibitors of water and carbon dioxide in polyurethane adhesives. Molecular sieves are crystalline silicoaluminates with a skeletal structure, featuring a uniform microporous structure and an extremely high specific surface area. Their pore diameters are comparable in size to those of common molecules, enabling the separation of molecules of different sizes. The commonly used molecular sieves are artificially synthesized. Synthetic molecular sieves are white powders, non-toxic, odorless, non-corrosive, and insoluble in water and organic solvents. It can dissolve in strong acids and strong alkalis.

The adsorption effect of molecular sieves has two most prominent characteristics: one is selective adsorption; The other one is efficient adsorption. Only those molecules with diameters smaller than the pore size of the molecular sieve can pass through the molecular sieve channels and be adsorbed. However, molecules with large configurations cannot enter the channels and thus cannot be adsorbed by the molecular sieve. By choosing the appropriate molecular sieve, water and carbon dioxide can be selectively adsorbed without adsorbing other components.

Most of the existing molecular sieve powders are prepared by high-temperature calcination of conventional molecular sieve raw powders, which have high surface activity and are prone to agglomeration. At the same time, due to the effect of hydroxyl groups on the surface of the molecular sieve, it is difficult to wet in organic media, resulting in problems such as poor powder dispersion, easy increase in the viscosity of the oil slurry, and shortened product shelf life. The performance of conventional molecular sieve powder is far from meeting the requirements of polyurethane formulation development, which hinders the wide application of molecular sieve powder in polyurethane systems. CHEMXIN has conducted in-depth research and development in response to the current problems of molecular sieve powder and launched a series of modified activated powder products. This series of products enhances the interaction and compatibility between inorganic and organic phases, weakens the surface polarity of the powder, and improves its compatibility and binding force with organic molecules. It not only has a high adsorption capacity but also a fast adsorption speed. At the same time, this series of products have extended the applicable period of the prepared adhesive solution and enhanced the bonding strength of the adhesive, enjoying an excellent reputation in the industry.

CHEMXIN has engaged in Molecular Sieve since 2002, over 23 years of experience in manufacturer, development and installation guidance. Let’s share more cases and study together.

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