| 摘要 |
1,241,538. Electro-phoretic painting; modifying and conversion coating zinc surfaces. BALM PAINTS Ltd. April 3, 1970 [April 11, 1969], No. 15959/70. Headings C7B and C7U. A Zn surface is coated by (a) drenching it with an aqueous conditioning solution of pH at least 13 comprising 1À5 to 10À0% NaOH or KOH with at least 0À05% each of a source of iron ions (as total Fe added), e.g. powdered Fe, Fe 2 O 3 or hydroxide, FeSO 4 , FeCl 3 or ferric citrate, and a sequestering agent for Fe, e.g. gluconic, heptonic or tartaric acid or Na or K salt thereof, triethanolamine, or sorbitol or mannitol employed with E.D. T.A., with or without a surfactant; (b) water rinsing; (c) depositing a zinc phosphate 'conversion' coating on the surface; and (d) electro-phoretically depositing thereon a paint film, e.g. comprising a polycarboxylic acid resin binder, neutralized with ammonia, water-soluble amine or NaOH or KOH, with or without red oxide pigment. The paint film may be baked. The conditioning solution may be applied by spraying, flow-coating or dipping. The zinc phosphate solution may also contain an accelerator and a grain refiner. The Zn surface may be of Zn strip or sheet, a Znbased die-casting alloy, or a Zn coating applied to iron or steel by hot dipping or electrodeposition, and passivated by an aqueous solution of a Cr salt. |
