Metal pigment composition
AssigneeSilberline Limited
InventorJonathan Joseph Whistler Knox
Life of this patent
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Abstract
There is provided a process for preparing a low- or non-dusting substantially non-volatile (preferably highly light reflective) metal flake pigment composition, which comprises ball milling atomized metal powder in a milling fluid substantially comprised of water, in the presence of one or more corrosion inhibitors and a substance which acts as a lubricant for the milling process. Optionally, the paste may be formed into granules for easy storage. Preferred metal pigments are aluminum or gold bronze and in one embodiment the metal pigment is aluminum, the lubricant is oleic acid and the corrosion inhibitor is a phosphate ester having a polyethylene oxide side chain. Agent(s) having both lubricating and corrosion inhibiting properties are preferred as additives.
Claims21
A process for preparing a low- or non-dusting, substantially non-volatile metal flake pigment composition, said process comprising ball milling atomised metal powder in the presence of a milling fluid, together with one or more additive(s) which together exhibit lubricating, corrosion inhibiting and surfactant properties, wherein the lubricant is not suet;
- wherein said milling fluid consists of water with a maximum content of organic solvent of 10% by weight.
A process for preparing a low-or nondusting, substantially non-volatile metal flake pigment composition, said process comprising:
- (a) ball milling atomised metal powder in the presence of a milling fluid, together with either an additive having both lubricating and corrosion inhibiting properties or with a lubricant and at least one corrosion inhibitor, wherein said milling fluid consists of water with a maximum content of organic solvent of 10% by weight, to produce a metal flake pigment;
- and
- (b) forming a coherent paste of an organic binder medium, water and said metal flake pigment, wherein said paste is formed by mixing a first component comprising organic binder medium and a second component comprising said metal flake pigment, with either or both of the first and second components comprising water and the paste containing from 3-70% of the organic binder medium based on the weight of the metal flake pigment, and either sub-dividing the coherent paste into particles and removing substantially all volatile liquids from the particles, or removing substantially all volatile liquids from the coherent paste and sub-dividing the resulting mass into particles, at least 98% by weight of the resulting particles being retained on a sieve having 150 μm aperture and each containing a plurality of metal pigment particles dispersed in a matrix of organic binder medium, wherein the organic binder medium binds the metal flake pigment particles by either precipitation from solution during volatile liquid removal, or sintering or melting at elevated temperature and fusion.
An organic solvent-free paste comprising a ball-milled metal flake pigment, water and agent(s) having lubricating and corrosion inhibiting properties, wherein said metal flake pigment is produced by ball-milling metal powder in a water-based milling fluid.
A metal pigment composition in granular form containing a plurality of milled metal flake pigments dispersed in a matrix of organic binder medium without any organic solvent present wherein said milled metal flake pigments are provided by milling using a water-based milling fluid.
Dependencies are inferred from the claim text.