Polymers and Coatings FAQ's

“Molecular Sieve” is a pretty general reference term used by chemists. It is most commonly used to describe forms of synthetic aluminosilicate known as ‘Zeolites’.

Zeolites such as 3A SUPERSIV are referred to as ‘Molecular Sieves’, because they tend to preferentially absorb one molecule from a selection of other molecules on-offer. Thus, they appear to ‘sieve out’ some molecules and not others.

Molecular Sieves are used in many different industrial applications. Some are used as reacting surfaces for catalysts in Petroleum Chemistry, others are used for their abrasive properties (e.g. in Laundry Detergent powder), and some, such as 3A SUPERSIV are used as desiccants (‘desiccants’ are a form of ‘drying agent’).

A-Type Zeolites are the most common form of Desiccant Molecular Sieves. You will most frequently see types 4A and 3A used in polymer formulations. 3A Zeolites tend to sieve-out water (and not much else) when exposed to a mixture of different chemicals. 4A Zeolites can also be used as an alternative but are not as effective. Both 4A and 3A Zeolite are used for the removal of Carbon Dioxide from Polyurethane Systems (and from Polyurea Systems also).

Zeolite Powder material looks like a fine white baking flour and has the exact same appearance when dry and also when completely saturated.

These powders differentially attract molecules from the air, or differentially attract molecules from within a mixed solution. In performing this task, the powder “sieves out” certain molecules and not others, and this is why these Zeolite Powders are known as “Molecular Sieves”

One of the most common uses of Molecular Sieve is for the removal of water from within polymer reactions, to prevent the chemical reaction from proceeding along an undesirable reaction pathway, which leads to unwanted end-products.

To achieve zero bubbles, manufacturers of PU-Elastomers and PU-Resins, use 3A SUPERSIV Powder (also known as Molecular Sieve and Moisture Scavenger) to remove this water, which can cause the bubbles to appear. The result is an attractive PU-Paint or PU Casting without any surface blemishes, or ugly blisters.

A Zeolite Powder such as 3A SUPERSIV is used to absorb the excess water that may be present in the Isocyanate, Polyol or filler components.

Molecular Sieve is used for the removal of water from polymer reactions, to prevent the chemical reaction from proceeding along an unattractive reaction pathway, which leads to unwanted end-products.

Manufacturers of solvent-based PU adhesives typically use a Zeolite Powder such as 3A SUPERSIV, to absorb the excess water that may be present in the Isocyanate, Polyol or filler components. Once the water has been removed, the remaining raw materials will react together, to create a bubble-free 2KPU adhesive.

Manufacturers who do not have the processing machinery required for the dispersion of fine powders into liquids, should note that there is also a convenience product available called 3A SUPERSIV Paste. This is a pre-blended liquid that manufacturers can simply pour-in to their formulation. It is easy to handle, and it mixes into polymers very well.

To receive a free sample of Molecular Sieve Powder click on the link here, and for a free sample of Molecular Sieve Paste, click on the link here

If you are making a 2-component polyurethane glue, and you are experiencing problems with unsightly bubbles, then add Zeolite Powder to your formulation. This material acts as a moisture scavenger and enables the reaction to proceed without the presence of water.

When you add Zeolite Powder in the formulation of Polyurethane Glue, this new ‘water free’ reaction mixture cannot generate any CO2 gas (which is the cause of the bubbles) and therefore, your problem is solved !

When tackling problems such as the removal of (water-generated) CO2 bubbles from Polyurethane formulations, most chemists opt to use molecular sieve such as 3A SUPERSIV Powder, as their moisture-scavenger. This is a proven solution, and it has been used for many years within the Coatings, Sealants, Adhesives and Elastomer industry (also known as the C.A.S.E. Market).

Zeolite Paste is typically a 50:50 mix of Zeolite Powder and high-quality Castor Oil paste. This pre-dispersed material can easily be poured into a liquid polymer coating or adhesive, during manufacture.

Our own 3A SUPERSIV Paste uses castor oil, because this oil is naturally hydroxylated, and thus aids polymerisation reactions.