ENTRY BOARDS FOR USE IN DRILLING SMALL HOLES

摘要

An entry board (1) for use in drilling small holes in boards. A lubricant layer (4) of a mixture of a polyethylene glycol having an average molecular weight of at least 3000 to less than 10000, a polyethylene glycol having an average molecular weight of at least 10000 and trimethylolpropane is formed over at least one surface of an aluminum base board (2), with an undercoat layer (3) of a partially saponified product of polyvinyl acetate provided between the layer and the base board. The partially saponified product of polyvinyl acetate is 15 to 70 mole % in the degree of saponification and 9000 to 50000 in average molecular weight. The entry board (1) is excellent in the adhesion of the lubricant layer (4) to the base board (2), and the lubricant layer (4) is prevented from cracking.