Custombond PUR-HM is a range of unfilled single component Polyurethane reactive hotmelt adhesives ( or PUR ). PUR is one of the fastest growing classes of adhesive worldwide. They can be used in many areas to replace solvent-borne adhesives as they offer exceptionally high performance in terms of adhesion and toughness, coupled with an instant bond.

CustomBond PUR-HM adhesives are heated in order to apply them in a molten state. Upon cooling they will solidify, forming an initial bond. Where they differ from conventional hot melt adhesives is in their moisture-curing properties. After exposure to moisture present in the atmosphere and in many substrates, the isocyanate groups in the adhesive undergo further polymerisation reactions to give a thermoset material, highly resistant to temperature changes, many chemicals ( excellent dry clean resistance ) and to mechanical stresses.

Although the CustomBond PUR-HM range are typically applied at temperatures of around 120 °C, the application uses far less energy than drying tunnels, which are necessary for water-based adhesives. Also the application temperature of PUR hot melt adhesives is considerably lower than that for conventional thermoplastic hot melt adhesives – typically 160 °C – 190 °C.

There are several different methods that can be used to apply PUR adhesives. For very flexible substrates where light coat weights are required, such as fabrics and films, the adhesive can be applied by swirl applicators, fibre applicators or gravure roller coaters. For economy when making regular products gravure rollers are often the applicator of choice.

The range is available in a variety of melt viscosities and green strengths.

A good adhesive bond can be attained with coatweights as low as 5 to 20 grammes per square metre.

Custombond HMR products are designed for;