The role of adding molecular sieve powder in polyurethane adhesives

Two-component polyurethane adhesives are adhesives obtained by the reaction of isocyanates and hydroxyl-containing compounds, and their molecular chains contain carbamate groups (-NHCOO-) or isocyanate groups (-NCO) ‌1. This adhesive usually consists of two components: one is an isocyanate component containing NCO (curing agent component B), and the other is a hydroxyl component containing hydroxyl groups (main agent component A) ‌.

Two-component polyurethane adhesives have excellent bonding properties, chemical stability and high temperature resistance. Our well-known applications include potting glue, aluminum honeycomb glue, purification board glue, waterproof coatings, etc., and Xintao powdered molecular sieves are often used in the synthesis of polyurethane materials as an additive for removing water and bubbles. When there is a trace of water or acid in the hydroxyl component in the two-component polyurethane system, it will react with isocyanate to produce carbon dioxide, thereby generating bubbles in the product and affecting the bonding strength.

Xintao powdered molecular sieve is a kind of aluminosilicate crystal with selective adsorption. It can adsorb water molecules and gas molecules, effectively remove trace moisture and other small molecular impurities in the hydroxyl component, and avoid bubbles.

In the actual application scenarios of two-component polyurethane adhesives, whether it is potting, bonding or rolling coating, there are different requirements for the open time after the combination of AB components. Especially in the use of aluminum honeycomb panel products, purification panels, and manual polyurea products that are popular in the market, workers have high requirements for the open operation time of adhesives. Conventional powdered molecular sieve materials will release heat during the rapid adsorption process. As the temperature increases, the combination reaction of AB components is faster, and the open time is shortened.

In order to meet the actual application needs of end customers, Xintao has launched a modified powdered molecular sieve product. While maintaining the performance of efficient adsorption, it reduces the combination reaction rate of AB components and plays a role in delaying the open operation time. At present, its performance has been recognized by a large number of customers and is in stable supply.

If you also have problems with curing development time, please feel free to contact us for more information and to receive sample tests.