Polypropylene (PP) bonding has always been a tricky proposition – to achieve a truly structural PP bond that will survive both high and very low service temperatures, welding is probably still the best option.
However, over recent years polypropylene based hot melt adhesives have been developed and are being used more and more regularly to bond Polypropylene.
From automotive to packaging applications, it is now possible to create bonds that are durable enough by using these specific hot melt adhesives.
Care must still be taken when bonding PP as the adhesive needs to be applied at the highest temperature possible, and the bond made before the heat is lost.
Tecbond adhesives are optimised for particular applications, for example tecbond 263 applied at 200C will bond PP to PP, but it will not bond PP to other plastics. Products like tecbond 267 and 261 will bond PP to other materials and tecbond 267 is used extensively in the automotive trim market for its unique combination of adhesion and temperature resistance.
Tecbond 261 and 420 formulations are used for the assembly of Corex PP board, which is used in many semi-permanent applications such as packaging cases and estate agents signs.
When bonding polypropylene, we recommend using the industrial tec glue guns that can be set as close to 200C as possible and then maintain this temperature as the adhesive is dispensed, as this greatly improves bond strength.
It is also important that the amount of adhesive and the time taken to make the bond is well controlled to ensure consistency, but following these basic rules does now mean that it is now possible to bond Polypropylene effectively.