Highly corrosion-resistant surface-treated steel plate

A highly corrosion-resistant surface-treated steel plate comprising a zinc-deposited or zinc alloy-deposited steel plate, a chromate film formed on the surface of the steel plate and a film of a resin composition formed on the chromate film, said resin composition comprising a base resin obtained by adding at least one basic nitrogen atom and at least two primary hydroxyl groups to terminals of an epoxy resin, a polyisocyanate compound and silica, the base resin/silica weight ratio being in the range of from 99/1 to 30/70

A highly corrosion-resistant surface-treated steel plate comprising a zinc-deposited or zinc alloy-deposited steel plate, a chromate film formed on the steel plate and a film of a resin composition formed on the chromate film, said resin composition comprising a base resin obtained by adding at least one basic hydrogen atom and at least two primary hydroxyl groups to terminals of an epoxy resin, a polyisocyanate compound, silica and a chromium compound, the base resin/silica weight ratio being in the range of from 99/1 to 30/70 and the base resin/chromium compound weight ratio being in the range of from 99/1 to 60/40.

A highly corrosion-resistant surface-treated steel plate comprising a zinc-deposited or zinc alloy-deposited steel plate, a chromate film formed on the surface of the steel plate and a film of a resin composition formed on the chromate film, said resin composition comprising a base resin obtained by adding at least one basic nitrogen atom and at least two primary hydroxyl groups to terminals of an epoxy resin, a polyisocyanate compound, silica and a silane compound, the base resin/silica weight ratio being in the range of from 99/1 to 30/70 and the amount of the silane compound being 0.1 to 15 parts per 100 parts of the sum of the base resin and silica.

A highly corrosion-resistant surface-treated steel plate comprising a zinc-deposited or zinc alloy-deposited steel plate, a chromate film formed on the surface of the steel plate and a film of a resin composition formed on the chromate film, said resin composition comprising a base resin obtained by adding at least one basic nitrogen atom and at least two primary hydroxyl groups to terminals of an epoxy resin, a polyisocyanate compound, silica, a silane compound and a chromium compound, the base resin/silica weight ratio being in the range of from 99/1 to 30/70, the amount of the silane compound being 0.1 to 15 parts per 100 parts of the sum of the base resin and silica and the base resin/chromium compound weight ratio being in the range of from 99/1 to 60/40.

A highly corrosion-resistant surface-treated steel plate comprising a zinc-deposited or zinc alloy-deposited steel plate, a chromate film formed on the surface of the steel plate and a film of a resin composition formed on the chromate film, said resin composition comprising a base resin obtained by adding at least one basic nitrogen atom and at least two primary hydroxyl groups to terminals of an epoxy resin and silica, the base resin/silica weight ratio being in the range of from 99/1 to 30/70.

A highly corrosion-resistant surface-treated steel plate comprising a zinc-deposited or zinc alloy-deposited steel plate, a chromate film formed on the surface of the steel plate and a film of a resin composition formed on the chromate film, said resin composition comprising a base resin obtained by adding at least one basic nitrogen atom and at least two primary hydroxyl groups to terminals of an epoxy resin, silica and a chromium compound, the base resin/silica weight ratio being in the range of from 99/1 to 30/70 and the base resin/chromium compound weight ratio being in the range of from 99/1 to 60/40.