Solventless polyurethanes components

First-generation solventless polyurethane adhesives are one-component isocyanate terminated prepolymers formed by the reaction of MDI (4,4 methylene bis (phenyl isocyanate)), or other isocyanates with polyether and/ or polyester polyols. One-component 100% solids adhesives rely on moisture from the air or substrates or from induced moisture misting during the converting process, to cure the adhesive via an isocyanate/water reaction and subsequent polyurea-polyurethane polymer formation. Typically the high viscosity of the adhesive is such as to require adhesive delivery equipment and application rollers heated from 65-80 °C for use. They have a high level... 

Second-generation solventless polyurethane adhesives Two-component second-generation adhesive systems are the most widely used of the 100% solids products. These two-part adhesives comprise an isocyanate terminated prepolymer based on the reaction product normally of MDI and polyols (polyether or polyester) in the presence of excess isocyanate, and a polyol (polyether or polyester based). 

Components of solventless polyurethane adhesives Aliphatic isocyanates used in polyurethane adhesives include ... 

Depending on their use and characteristics, solvent or solventless polyurethane based adhesives are available and can also be customised for special packaging requirements. Some typical uses for one-component PUR adhesives are for adhesion of shopping bags, printed films, and adhesives for snack food bags. These are especially suitable for these applications mainly because they are solvent free, moisture curable, and easy to apply. 

---