DRILLING MASK Russian patent published in 2014 - IPC B26F1/16 H05K3/00 

FIELD: process engineering.

SUBSTANCE: invention relates to drilling mask for frilling in copper-clad laminar material or in sandwich board. Said mask is made of metal foil one side of which is coated with water soluble polymer composition B containing 80 to 98 wt % of polyethylene [polyoxyethylene] glycol with mean molecular weight making 15000 to 35000, 2 to 20 wt % of polyethylene oxide with mean molecular weight making 50000 to 200000, and 0.1 to 5 wt % of at least one water soluble substance selected from the group of polyatomic spirits, amino acid derivatives of spirits, organic acids and organic acid salts.

EFFECT: higher precision of hole configuration, lower probability of polymer sticking to drill bit and bit breakage.

5 cl, 1 tbl, 9 ex