MOLECULAR SIEVE FOR CARPET BACKING

Carpet Backing and Polyurethane

Many substances are added to Carpet Backing or Polyurethane.  Dehydrating agents such as molecular sieves 3A and 4A are used regulate water content. Preferably these materials are incorporated in the polyol blend.  Generally, all ingredients except the isocyanate are preblended into the polyurethane matrix. This is commonly called the polyol blend. The isocyanate is sensitive to water and is thus removed by the molecular sieves.

 

3A molecular sieve does not adsorb gases that would be later cause bubbles and surface defects.  4A molecular sieve can be added to the resin/solvent system under vacuum to remove any displaced gasses.  In polyurethane systems, approximately 1-2% of the matrix is based on molecular sieves.

 

3A Molecular Sieve powder is the calcium form of the type A crystal structure.  It is an alkali alumino-silicate that is useful in formulations.   Sepcor 3A Molecular Sieve will adsorb water to very low levels with high adsorption capacity. Unlike chemical drying agents, these adsorbents function by a physical process only, so no reaction by-products are formed that can adversely affect product properties.

 

Many coating, sealant, adhesive or cosmetic products are extremely susceptible to moisture contamination during production and storage. Moisture can be introduced into these systems from pigments and fillers, as well as from exposure to ambient moisture during their production.