DRILL HOLE ENTRY SHEET

摘要

Provided is a drill hole entry sheet that: is formed on at least one side of a metal support foil from a crystalline, water-soluble resin compound as a layer 0.02-0.3 mm thick; has excellent hole position accuracy; is formed from a resin that does not cling to the drill bit; and protects the drill bit from damage. The crystal particles of the water-soluble resin compound have an average diameter of 5-70 µm and a standard deviation of 25 µm or less. The drill entry surface of the layer formed from the water-soluble resin compound has a surface roughness (Sm) of 8 µm or less. After a hot melt of the water soluble resin compound is directly applied to the metallic support foil or after a solution that contains the water soluble resin compound is applied to the metallic support foil and dried, the aforementioned layer is formed by being cooled from 120-160 ºC to 25-40 ºC within 60 seconds at a cooling speed of 1.5 ºC/s or greater.