Polyester polyols – high-performance adhesive

Polyester polyols are derivatives of dicarboxylic acids and polyols, which are organic compounds with several groups of hydroxyl. Those with two, three and four hydroxyl groups are called diols, triols and tetraols respectively. In general, a polymer is simply referred to as a polyol once it has more than four hydroxyl groups. The "polyester" part of the name indicates the presence of ester groups. Polyester polyols are mostly linear polymers with oxygen and carbon branches and can react with isocyanate to form prepolymers. They are mainly synthesized from petroleum but can also be made from plant-based oil. Newer methods even allow them to be produced using recycled materials. One main application of polyester polyols is for the production of polyurethane, which itself is a starting material for various plastics. This process involves the reaction of polyester polyols with diisocyanates.

Polyester polyols can help materials achieve a high level of resistance to light and heat. In addition, PP-based coatings exhibit high strength and abrasion resistance. Polyurethane is a polymer created by the reaction of diols or other polyols (which can be polyester or polyether polyols) with polyisocyanates. Polyols form the flexible segments in polyurethane and therefore have an effect on the material's rigidity. Polyester polyols with high molecular weight are suitable for making soft, flexible polyurethane, whereas those with relatively low molecular weight will result in a more rigid material. Their viscosity also increases with their molecular weight. Polyester polyols can impart the following properties to polyurethane:

• Water resistance
• Abrasion resistance
• Cut resistance

How resistant the resulting polyurethane is to water, abrasion and cut depends on the molecular weight of the polyester polyol selected.