DRILLING MASK Russian patent published in 2016 - IPC B26F1/16 B23B35/00 

FIELD: construction.

SUBSTANCE: invention relates to the process of drilling holes in a multilayer panel or a multilayer printed circuit board. Mask comprises a metal bearing foil and a layer of water-soluble polymer composition formed on at least one of its surfaces, which contains a water-soluble polymer, a water-soluble lubricant and a straight unsaturated fatty acid salt. Layer of water-soluble polymer composition is obtained by cooling from the initial cooling temperature of 120-160 °C down to the final cooling temperature of 25-40 °C during 60 seconds with the cooling rate of not less than 1.5 °C/sec. Degree of crystallinity of the water-soluble polymer composition is not less than 1.2, the surface hardness of the water-soluble polymer composition layer ranges from 8.5 to 25 N/mm² at the standard deviation of the surface hardness value of not more than 2.

EFFECT: higher accuracy of holes arrangement and of drilling quality.

15 cl, 4 dwg, 4 tbl