The increased use of alternative capstocks in vinyl siding has brought benefits, especially improved weathering in medium and dark colors, There have been challenges as well due to the fact that two dissimilar materials are now being co-extruded into a single sheet. One such challenge is the increased tendency of alternatively capped materials to warp, both during and after production. In this paper we examine the role of orientational stresses introduced during production and how these stresses are affected by a mismatch in glass transition between the substrate and capstock layers.
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