Clariant describes the material as having two to three times greater color strength in polyethylene and PVC as conventional lead chromate
yellows, and adds that in combinations with inorganic pigments H4G achieves a close match to the color and opacity of lead chromates
If lead is in the form of lead chromate
, chromium content should increase linearly with lead content.
This process forms particles with a core made of lead chromate
sulfate and a shell of lead sulfate.
Table 1: Coil coating sample formulations Sample Color Pigment weight (%) Overall PVC CPVC CY Yellow Lead chromate
(44%) 15.8 37.2 Titanium dioxide (3%) CR Red Iron oxide (23%) 7.4 40.3 Titanium dioxide (1%) CB Blue Copper phthalocyanine (10%) 10.5 47.3 Titanium dioxide (12%) All coatings were cast as liquid films, on a polyester-melamine-primed aluminum substrate, using a wire-wound draw-down bar of a diameter suitable to obtain a film thickness of ~20 [micro]m.
Lead is also used in car batteries and for the manufacture of paints such as white lead chromate
and other pigments.
The company was condemned for allowing workers to spray paint, containing toxic lead chromate
, without adequate controls in place, leaving them to breathe in harmful fumes and absorb lead into their blood.
Examples included the use of poisonous lead compounds such as red lead to colour cheese and yellow lead chromate
in custard powders and the poison strychnine used as an alternative to hops for bitterness in beer.
Chromate pigment production involves reacting sodium chromate with zinc or lead to produce insoluble zinc chromate and lead chromate
* Two samples were painted with paint containing lead chromate
(0.1% and 0.5% lead), with each sample covered by a non-leaded paint.
Color pigments include high-value Synergy pigments designed to reduce costs for formulators of industrial coatings; Meteor and Meteor Plus complex inorganic pigments for applications requiring heat resistance and exterior durability; Engeltone organic pigments in a wide spectrum of colors; Engeltone low-soluble cadmium pigments for uses requiring good heat and light stability; and Engeltone lead chromate
and moly orange pigments for cost-effective coloring.
However, in actual practice, other nonpermitted synthetic dyes like auramine, metanil yellow, lead chromate
, rhodamine, sudan-3 and 4, orange-2 and Malachite green, which pose serious health hazards, as they are mutagenic and potential carcinogens, are being used as food colours in the market.
In the paint and coating industry, federal regulations strictly limit the use of lead chromate
pigments--which give traffic markings their distinctive yellow color--to industrial products like traffic paints, finishes for machinery, and equipment and metal primers, says, Steve Sides, vice president of environmental health and international affairs for the National Paint and Coatings Association, a Washington, D.C.-based trade organization.
exposures and elevated blood lead levels in workers in the blood lead levels in workers in the plastics pigmenting industry--Texas, 1990.
34) and the lead chromate
molybdate sulphate red (PR.
producers in Europe like Cappelle and BASF are switching completely to substitutes like bismuth vanadate pigments.