A method for assessing the effect of polymer sheeting rheology, surface pattern, and processing conditions on glass lamination

An apparatus has been constructed wherein the transparency of a glass/polym er sheet/glass assembly undergoing vacuum de-airing can be monitored contin uously. Experimental conditions can be varied independently, such as vacuum level, cold (ambient) de-airing time, and oven temperature. The behavior o f polyvinyl butyral and an ionomeric interlayer (SGP) with different rheolo gical properties and surface roughness were studied using various de-airing conditions. initial results show that the clarity of the assembly is a mon otonically increasing function of time in the oven at a given vacuum level. All assemblies made from these interlayers became clear with sufficient va cuum time at ambient temperature. The assembly from polyvinyl butyral with protrusion-type surface pattern clears up faster than that with indentation -type. (C) 2001 John Wiley & Sons, Inc.