RCN SOLUTIONS, as a manufacturer of laminating machines, would like to point out some important matters in the discussions around PVB (Polyvinyl Butyral) and EVA (Ethylene Vinyl Acetate).
The most important question when the name PVB is mentioned revolves around the process in autoclave versus autoclave-free machines: can be PVB processed without the autoclave system?
There exists a wide body of literature explaining how to use PVB in bagging laminating machines and RCN agrees on the possibility to process PVB with some autoclave-free equipment.
While it is possible, some other aspects should be taken into consideration. The process in autoclave involves some steps, including pre-pressing and pre-heating to be passed to high pressure later. PVB is a very sensitive product requiring special storage and clean rooms for preparation.
This said, to process PVB in systems different than autoclave is workable, but by its nature, PVB also needs all the facilities mentioned above. If an interleaved PVB is easier to use, once unpacked, it behaves like a regular one.
But there are other considerations: the laminating time with PVB is much longer than with EVA, in some cases double the time. The laminating volumes are smaller and, the crucial question is, has the PVB been processed into a bagging system with the same adhesion rate as the PVB processed in an autoclave? Will it be approved according to the European and International standards?
The 12 bar pressure of the autoclave assumes there are special requirements in processing the PVB interlayer with the expected results of clearness and adhesion.
Something not talked too much about, but is a very important matter. The customer should require pummel test results when purchasing autoclave-free equipment running with PVB. It is important because it determines the quality adhesion of safety glass laminated with PVB.
PVB laminated glass can be produced without visual defects from an autoclave-free system, but the adhesion capacity is of absolute importance. RCN SOLUTIONS suggests contacting qualified PVB manufacturers to be guided on this matter before starting production.
The market now offers some hybrid products, such as rigid plastics, that perform well and can be used without special conditions in the bagging systems.
REVA BF by RCN SOLUTIONS possesses very special properties that in some applications proved superior to other similar interlayers, for adhesion, transparency and convenience.