| 摘要 |
<p>Aqueous zinc-alkali metal silicate anticorrosive coating compositions comprise as hardening or curing agent a carboxylic acid amide which is solid at room temperature and has an aqueous solubility at 15 DEG C. of less than 1% by weight. Preferred are amides of M.Pt. above 50 DEG C., e.g. oxamide, succinamide or adipamide, in an amount 12-60% by weight of the alkali metal silicate. The latter may be sodium silicate of Na2O: SiO2 ratio 1:2.5-3.75 or potassium silicate of K2O:SiO2 ratio 1:2-2.5 which may be made up to a 30-55% by weight solution in water. The zinc dust comprises 5-25 parts per part silicate. Additional curing agents such as Pb3O4, Cr2O3, K2Cr2O7, ZnS or Ca, Mg or Zn peroxide may be present in amounts up to 20% by weight of the zinc. The binary mixes carboxylic acid amide plus either powdered zinc or alkali metal silicate are also claimed.ALSO:Metals, specifically steel panels, are anti-corrosively coated with an aqueous zinc-alkali metal silicate composition comprising as hardening or curing agent a carboxylic acid amide which is solid at room temperature and has an aqueous solubility at 15 DEG C of less than 1% by weight. Preferred are oxamide, succinamide or adipamide. Additional curing agents such as Pb3O4, ZnS or Ca, Mg or Zn peroxide may be present. Conventional coating means such as spraying (Examples 1-6), brushing or trowelling are used.</p> |
