Disclosed is a polished translucent co-extruded sheet having utility as a light diffusing protective cover or sign face for light emitting diode (LED) light sources and other purposes. The sheet is comprised of (a) a particle layer containing particles having a mean particle size of about 4 to 100 microns and having a particle size distribution of between 1-110 microns, at a loading of 1 to 60% melt blended with a thermoplastic matrix, wherein the particle and matrix have refractive indices that differ by greater than 0.001 units of each other when measured in conformance with ASTM D 542; and (b) at least one substrate layer comprised of thermoplastic compositions, wherein the substrates have a refractive index within 0.2 units of the refractive index of the particle layer matrix when measured in conformance with ASTM D 542.
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机译：公开了一种抛光的半透明共挤出片材，其具有用作发光二极管（LED）光源和其他目的的光漫射保护盖或标志面的用途。该片材由（a）颗粒层组成，该颗粒层包含平均粒径为约4至100微米且粒径分布在1-110微米之间的颗粒，其负载量为1至60％，与热塑性塑料熔融共混。基质，其中当按照ASTM D 542进行测量时，颗粒和基质的折射率彼此相差大于0.001单位; （b）至少一层由热塑性组合物组成的基材层，其中当按照ASTM D 542进行测量时，这些基材的折射率在颗粒层基质的折射率的0.2个单位内。
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