Application

Coating, Sealants , Adhesives

2016-02-23

One of problems of Polyurethane Polymer is the moisture. If not removed, moisture will react with the isocyanate to form carbon dioxide gas and then leads to formation of bubbles in final compound:
RNCO + H2O → RNH2 + CO2

Molecular sieve powder is highly effective, non-toxic moisture scavenger for 1K- and 2K Polyurethane systems to prevent the formation of foam and bubbles by suppressing the reaction of free water with the isocyanate group. At the same time, molecular sieve powder is well compatible with commonly used polyols, polyethers and isocyanates. They are easily dispersible and especially stabilized to ensure sufficiently long hardening times.

In certain paint and coating systems, moisture introduced into the formulation via the raw materials (solvents, pigments, extenders) causes undesirable side effects. In metallic and zinc-rich paints (such as marine paints for tank ships and yachts), water reacts with the very active metallic pigments such as zinc or aluminum, forming hydrogen. This leads to overpressure in the cans, and in extreme cases to leakage.
Zn+H2O→Zn(OH)2+H2

Al+H2O→Al(OH)3+H2

In metallic and zinc-rich paints, the adverse effect can be avoided by the use of JLH-03-B, JLH-04, JLH-05A, JLH-013. It adsorbs the moisture rapidly, with the result that the above reactions can be suppressed, thus reducing returns and storage problems.