Bonding of Insulation Glasses into PVC Sashes by Reactive Warm Melt

Bonding of Insulation Glasses into PVC Sashes by Reactive Warm Melt 

Another benefit comes from the fact that new designs are feasible without the use of the metallic stiffening profile. Since the window is bonded at its edge with Sikaflex -650 AI, the glass of the window contributes to the load-bearing capacity and higher stiffness is achieved. 

The joining of the window through bonding enables new window designs with reduced frame cross sections and higher overall stiffness, which prevents the window from unwanted bending. 

In this application, the grey-coloured Sikaflex -650 AI is either injected by a nozzle or sprayed at 80°C between the insulation glass and the PVC frame. After application, the polyurethane warm melt cools down and achieves sufficient handling strength after only 2.5 min, i.e., the insulating glass is stabilised in the frame. The entire bonding process can be fully automated and this enables the production process to be accelerated. 

After 1 week, Sikaflex -650 AI cures with moisture to a final strength of 2.5 MPa, shore A hardness of 60,450% elongation with excellent adhesion to the substrates. For optimised adhesion on PVC, a pretreatment with SikaPrimer -215 AI with a minimum open time of 10 min is applied. Further, Sikaflex -650 AI must also adhere to 2C-PUR systems when present and they must also be pretreated with SikaPrimer -215 AI. 

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