ENTRY SHEET FOR DRILLING USE

摘要

The present invention relates to an entry sheet for drilling use, which exhibits excellent hole position accuracy even when transported at ambient temperature for a long time and/or stored under a thermal environment having a higher temperature than in Japan, more specifically to an entry sheet for drilling use for a laminated board or a multi-layered board comprising a metallic support foil and a layer of water-soluble resin composition formed on at least one surface of the metallic support foil, wherein the water-soluble resin composition comprises a water-soluble resin, a water-soluble lubricant and a linear unsaturated fatty acid salt, the layer of water-soluble resin composition is formed by cooling from a cooling start temperature of 120° C. to 160° C. to a cooling end temperature of 25° C. to 40° C. within 60 seconds at a cooling rate of not less than 1.5° C./sec, the water-soluble resin composition has a degree of crystallinity of not less than 1.2, the layer of water-soluble resin composition has a standard deviation σ of surface hardness of not more than 2, and a surface hardness of not less than 8.5 to not more than 25 N/mm2.

主权项

1. An entry sheet for drilling use for a laminated board or a multi-layered board comprising a metallic support foil and a layer of water-soluble resin composition formed on at least one surface of the metallic support foil, wherein
the water-soluble resin composition comprises a water-soluble resin, a water-soluble lubricant and a linear unsaturated fatty acid salt, the layer of water-soluble resin composition is formed by coating on the metallic support foil, a hot melt of the water-soluble resin composition, or coating on the metallic support foil, a solution containing the water-soluble resin composition and drying it, and then cooling it from a cooling start temperature of 120° C. to 160° C. to a cooling end temperature of 25° C. to 40° C. within 60 seconds at a cooling rate of not less than 1.5° C./sec, the water-soluble resin composition has a degree of crystallinity of not less than 1.2, and the layer of water-soluble resin composition has a standard deviation σ of surface hardness of not more than 2, and a surface hardness of not less than 8.5 N/mm2 to not more than 25 N/mm2.