The PVB has been the standard film that is used to laminate Arquitectural glass. Surprisingly the adhesiveness of PVB to glass it is not outstanding. It might be considered between acceptable to poor, specially if we take into account the high mechanical tensions and efforts that the laminated glasses have to sustain as parts of building constructions (holes, clamps, vibrations, etc). The adhesiveness of the films interlayers to the glass is critical to avoid the undesirable, risky and expensive costly de-lamination glass defects.
Besides that, the PVB is considered as the reference lamination material. The PVB is taught in all Architectural Schools as the excellence glass lamination film. That is why all Architects consider it as the safest material to be used for lamination. The other films materials are considered the “risky ones” options.
The Materials science has brought to life a new generation of materials that are different and in some properties better than PVB. The NovoGlass SF is one of these new generation materials that has been developed and manufactured to specially improve its adhesiveness to glass, showing much higher values than PVB.
But, how better is the adhesiveness of NOVOGLASS®SF to Glass?
Currently the PVB is processed and laminated between glasses using high pressure inside autoclaves. In order to make things ease at NovoGenio we have developed the NovoGlass®SF film to be processed in autoclave also, but following similar procedures than the ones that are used for PVB.
It is known also that the pressure applied to laminates inside the autoclaves helps to increase the adhesiveness of PVB to glass. Is for that reason that we measured the adhesiveness of NovoGlass®SF to glass as a function of the pressure. Under the same conditions we compared the measured values to the PVB ones. The following table shows the measured results of adhesiveness to glass:
As data shows, in all pressure conditions the adhesiveness of NovoGlass®SF to glass is the same and the values are outstanding compared to the values. Moreover the same adhesiveness level is achieved at all pressures tested (always below 8 bar), even with just 1 bar pressure.
In the case of PVB the adhesiveness to glass is very low at 1 and 3 bar pressure. In general we can say that the adhesiveness of NovoGlass®SF to glass is at least 2.5 times higher than the one of PVB to glass. See below graph:
If we want to look at the robustness of the adhesiveness then we should ask the following question:
How the adhesiveness of NOVOGLASS®SF to Glass evolves?
To measure that, we can apply different methods to promote the accelerated aging of the prototypes. There are different analytical techniques and procedures to “challenge” the life of products.
Knowing that the humidity is one of the key parameters that contribute to the failure of the laminates, we have checked the resistance of the adhesiveness to glass under water influence.
The method we follow to “fast age” the laminates is based on keeping the laminated samples under high humidity conditions and controlled temperature. We submitted the laminates at several cycles of humidity to check the response to these conditions. Each humidity cycle (HC) consist on humidity treatment of the samples under water vapor conditions at 85ªC during 1 hour of treatment. After each cycle treatment we measured again the adhesiveness of the films to glass.
The lines 1st HC y 2nd HC refer to two first cycles of humidity treatment at which the samples were submitted:
As tabulated data shows the adhesiveness of NovoGlass®SF to glass doesn’t change after two humidity cycles in all cases (samples laminated at different pressures).
In the case of the PVB, the adhesiveness to glass change with the number of humidity cycles decreasing in a steady way. Since the starting adhesiveness values were low, even small losses are not acceptable at all.
In order to summarize all the data in a single graph we have constructed a plot were it can be easy seen the evolution of the adhesiveness of NovoGlass®SF and PVB when they were submitted to two Humidity Cycles in our labs. The below graph contains all the results grouped in lamination pressures and types of films tested.
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