Environmentally Pollution-Free Anti-Corrosion Pigment Composition

Abstract

The present invention provides an environmentally pollution-free, anti-corrosive pigment composition which is free of any heavy metal such as lead and / or chromium, which is free of zinc and / or water-soluble ions and which is excellent in the anti-corrosive effect. The anti-corrosive pigment composition comprises condensed calcium phosphate prepared by firing a mixture which comprises a calcium-containing component and a phosphorus-containing component and in which the molar ratio (Ca / P=m) of calcium to phosphorus present in these components falls within the following range: 0.50<m<1.00, at a temperature ranging from 180 to 350° C.

Description

TECHNICAL FIELD [0001] The present invention relates to an anti-corrosive pigment composition which can be incorporated into, for instance, anti-corrosive paints and, more particularly, to an environmentally pollution-free anti-corrosive pigment composition which is free of any heavy metal such as lead, chromium and / or zinc, which can be applied to, for instance, a variety of anti-corrosive paints and anti-corrosive oils, which has a wide variety of applications and which is excellent in the anti-corrosive effect. BACKGROUND ARTS [0002] Until now, as anti-corrosive pigments, there have widely been used lead-containing anti-corrosive pigments such as red lead, lead cyanamide and lead suboxide; and chromate-containing anti-corrosive pigments such as zinc chromate and strontium chromate. [0003] These lead-containing and chromate-containing anti-corrosive pigments have excellent anti-corrosive characteristics, but the use thereof has gradually been regulated while taking into considerat...

AI Technical Summary

Benefits of technology

[0015] The environmentally pollution-free, anti-corrosive pigment composition according to the present invention is free of any environmental pollution since it never comprises any harmful heavy metal element such as lead and / or chromium as well as zinc and thus shows an excellent anti-corrosive effect. This anti-corrosive pigment composition can be incorporated into various kinds of resin-containing paints and therefore, it is quite useful as a pigment used in anti-corrosive paints for a variety of metal materials.

[0016] Further, the anti-corrosive pigment composition of the present invention can be used according to the methods identical to those applied to other anti-corrosive materials or in various applications similar to those for the anti-corrosive pigments, for instance, the composition of the present invention can be added to anti-corrosive oils and the composition can likewise be used in the method of using the same as an inhibitor.

Problems solved by technology

More specifically, it is apprehended that they may hurt the human health.

These environmentally pollution-free anti-corrosive pigments are much less problem concerning the safety and hygiene, but the anti-corrosive properties thereof are in general inferior to those observed for the lead-containing and chromate-containing anti-corrosive pigments.

Furthermore, these environmentally pollution-free pigments cause various problems, for example, in that they require a high production cost and further they are deteriorated in their physical properties, dispersibility and storage stability.

Nevertheless, it has been considered questionable whether zinc-containing compounds, in particular, zinc oxide used as a pigment component is safe or not mainly in the United States and Europe, along with the recent intensified regulation of the environmental pollution.

This is because, it has been proved that zinc oxide may adversely affect the oceanic life or the marine animals and accordingly, there have been such a tendency to start self-controlling of the use of zinc oxide in the coating or painting of, for instance, containers for transporting foods, not to mention the use thereof in the places where it may have a bad influence.

In addition, when incorporating such a zinc oxide-containing anti-corrosive pigment into an oily vehicle such as boiled oil or an oily varnish, the zinc oxide reacts with the vehicle to thus cause a phenomenon or cohesion of pigment components called “seeding” and this in turn becomes a cause of a problem such as the development of insufficient appearance of the resulting coated film and the reduction of the physical properties of the same, as has been described in JIS K5621.

Moreover, the coated film containing such a zinc oxide-containing anti-corrosive pigment causes a problem in that it is liable to develop white rust on a zinc-plated plate.

However, these environmentally pollution-free, anti-corrosive pigments are still insufficient in both anti-corrosive properties and wide-spread applicability.

However, the anti-corrosive pigment composition thus prepared never ensures the desired long-lasting anti-corrosive properties since it comprises a large amount of water-soluble ions such as Na+, NO3− and Cl−.