| 摘要 |
<p>A pigment comprises particles having a silica core coated with cupric borate, the silica being from 25 to 75% by weight of the pigment and the silica particles being within the size range of from 1 to 20 microns. The pigment may be prepared by mixing the silica particles with the copper salt of an acid which forms a water-soluble salt with caustic alkali, adding caustic alkali to give a mixture of pH at least 8, filtering and removing the water-soluble salt, adding water to the filtered solids to form a thick paste to which boric acid is added, and drying the resulting paste at a temperature not exceeding 130 DEG C. In an example, silica (10-60 microns) and CuSO4.5H2O were wet ground in a ball mill to a particle size of 1 to 20 microns. The slurry was heated to 60 DEG C. and aqueous sodium hydroxide was added while stirring to give a mixture of pH 9.2. The mixture was filtered and the filter cake, after washing, was slurried and mixed with an aqueous slurry of boric acid. The resulting mixture was ovendried at 120 DEG C. before being ground. Paint formulations incorporating the pigment are given.ALSO:Antifouling and mildew-resistant paint formulations incorporate a copper borate-coated silica pigment. A typical mildew-resistant paint formulation comprises 59.8% pigment, consisting of 24.3% composite lead sulphatelead silicate pigment, 18.3% zinc oxide, 18.3% rutile, 36.1% magnesium silicate, 3.0% copper borate-coated silica, and 40.2% vehicle, consisting of linseed oil, volatile petroleum solvent, and drier.ALSO:Antifouling and mildew-resistant paint formulations incorporate a copper borate-coated silica pigment. A typical mildew-resistant paint formulation comprises 59,8% pigment, consisting of 24,3% composite lead sulphate-lead silicate pigment, 18,3% zinc oxide, 18,3% rutile, 36,1% magnesium silicate, 3,0% copper borate-coated silica, and 40,2% vehicle, consisting of linseed oil, volatile petroleum solvent, and drier. The paint may be applied to cedar panels.</p> |
