| 摘要 |
PROBLEM TO BE SOLVED: To provide a multi-layer sheet for laser marking which has excellent transparency, impact and scratching resistances and printability of black masks, etc. and is suitable for transparent covering materials, liquid crystal display covers, etc. SOLUTION: The multi-layer sheet 1 for laser marking comprises a laminate 4 consisting of a thermoplastic transparent heat-resistant resin layer 2 and a thermoplastic transparent resin layer 3, laminated by coextrusion. The resin layer 2 is composed of a thermoplastic transparent heat-resistant resin, and the resin layer 3 is composed of a thermoplastic transparent resin having a difference in the refractive index for the D-line wavelength of≥0.05 with respect to the thermoplastic transparent heat-resistant resin. The resin layer 2 contains 0.01-5 pts.wt. of an energy absorbent 7 absorbing the laser beam to 100 pts.wt. of the thermoplastic transparent heat-resistant resin. The multi-layer sheet has excellent transparency, impact and scratching resistances and printability of black masks, etc. and is suitable for transparent covering materials and liquid display covers. COPYRIGHT: (C)2009,JPO&INPIT
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