Protective Linear Materials for Transparent Plastics,
PPG INDUSTRIES INC PITTSBURGH PA GLASS RESEARCH CENTER
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Parasitic plies such as acrylic used to protect polycarbonate from the environment in aircraft transparencies and undersirable weight and are subject to crazing. PPG Industries has recently developed a family of elastomeric liner materials specifically formulated to provide complete isolation of the substrate to which it is substrate. This paper describes two specific liner materials. The first was designed to withstand the relatively severe environments encountered on the exterior surface of an aircraft transparency. The second was developed for use on the inboard surface where environmental considerations are not as demanding. Comprehensive testing and evaluation of these liners have been performed by PPG over the past two years. Environmental-resistance testing has included humidity exposure, ultraviolet radiation, chemical resistance, rain erosion resistance, accelerated and natural weathering, and abrasion resistance. The results of these tests have been very encouraging and the liners are currently being tested on full-scale transparencies. In addition, the outboard liner has been flight-tested for over a year with excellent results. The complete testing program for these liners, including field service performance, will be reviewed.