Acetone → Pyrogallol

Participants

Reaction Conditions

Reaction Steps

Both surfaces of a 0.24 mm thick aluminum plate were sand-grained using a nylon brush and an aqueous dispersion of 400 mesh pumice stone and thoroughly washed with water. This aluminum plate was dipped in a 5% aqueous solution of sodium triphosphate maintained at 70° C. for 3 minutes, washed with water, and dried. A photo-sensitive solution as described in British Pat. No. 1,113,759 was prepared by dissolving 1 part by weight of a naphthoquinone-1,2-diazido-5-sulfonic acid ester of polyhydroxyphenyl obtained by polycondensation of acetone and pyrogallol and 2 parts by weight of a novolak type phenol-formaldehyde resin in a mixed solvent of 20 parts by weight of 2-methoxyethyl acetate and 20 parts by weight of methyl ethyl ketone. This photo-sensitive solution was coated on one surface of the above-prepared plate and then on the other surface to produce a pre-sensitized printing plate which has photo-sensitive layers on both surfaces of the plate. The thus-produced printing plate was cut in three 1,003 mm×800 mm pieces to produce Samples A, B and C.

Provenance & Evidence