4. Refractive index: 1.70~2.25

It's all over the place in our environment, said Dr. Johnson-Arbor.

Titanium dioxide has been used as a bleaching and opacifying agent in porcelain enamels, giving them brightness, hardness, and acid resistance. In modern times it is used in cosmetics, such as in skin care products and sunscreen lotions, with claims that titanium dioxide protects the skin from ultraviolet radiation because of its property to absorb ultraviolet light.

The integrity of surface skin cells was evaluated with and without solar simulated irradiation. The integrity of the stratum corneum was significantly lower in individuals treated with P25TiO₂NPs under the light in comparison to the ones that received the functionalized nanoparticles. Cell membrane suffering is evident (Fig. 9), and it is in accordance with the ROS levels and macromolecule oxidation found in vitro for the irradiated P25TiO₂NPs. Disruption of the superficial skin layer was observed in all animals treated with no functionalized nanoparticles, under irradiation. This data expands the findings by the group of Professors Fubini and Fenoglio, who showed that P25TiO₂NPs could impact the lipid structure at the top few microns of the stratum corneum [55]. Control skin under irradiation and without any topic formulation did not show changes in cell structure.

A great number of other brands with fancy names have gone out of the German market, because of some defects in the processes of manufacture. The English exporters, as a rule, offer three or four grades of lithopone, the lowest priced consisting of about 12 per cent zinc sulphide, the best varying between 30 and 32 per cent zinc sulphide. A white pigment of this composition containing more than 32 per cent zinc sulphide does not work well in oil as a paint, although in the oilcloth and shade cloth industries an article containing as high as 45 per cent zinc sulphide has been used apparently with success. Carefully prepared lithopone, containing 30 to 32 per cent sulphide of zinc with not over 1.5 per cent zinc oxide, the balance being barium sulphate, is a white powder almost equal to the best grades of French process zinc oxide in whiteness and holds a medium position in specific gravity between white lead and zinc oxide. Its oil absorption is also fairly well in the middle between the two white pigments mentioned, lead carbonate requiring 9 per cent of oil, zinc oxide on an average 17 per cent and lithopone 13 per cent to form a stiff paste. There is one advantage in the manipulation of lithopone in oil over both white lead and zinc oxide, it is more readily mis-cible than either of these, for some purposes requiring no mill grinding at all, simply thorough mixing with the oil. However, when lithopone has not been furnaced up to the required time, it will require a much greater percentage of oil for grinding and more thinners for spreading than the normal pigment. Pigment of that character is not well adapted for use in the manufacture of paints, as it lacks in body and color resisting properties and does not work well under the brush. In those industries, where the paint can be applied with machinery, as in shade cloth making, etc., it appears to be preferred, because of these very defects. As this sort of lithopone, ground in linseed oil in paste form, is thinned for application to the cloth with benzine only, and on account of its greater tendency to thicken, requires more of this comparatively cheap thinning medium, it is preferred by most of the manufacturers of machine painted shade cloth. Another point considered by them is that it does not require as much coloring matter to tint the white paste to the required standard depth as would be the case if the lithopone were of the standard required for the making of paint or enamels. On the other hand, the lithopone preferred by the shade cloth trade would prove a failure in the manufacture of oil paints and much more so, when used as a pigment in the so-called enamel or varnish paints. Every paint manufacturer knows, or should know, that a pigment containing hygroscopic moisture does not work well with oil and driers in a paint and that with varnish especially it is very susceptible to livering on standing and to becoming puffed to such an extent as to make it unworkable under the brush. While the process of making lithopone is not very difficult or complicated, the success of obtaining a first class product depends to a great extent on the purity of the material used. Foreign substances in these are readily eliminated by careful manipulation, which, however, requires thorough knowledge and great care, as otherwise the result will be a failure, rendering a product of bad color and lack of covering power.

Lithopone manufacturer: Application areas

A dense, white, opaque pigment composed of a mixture of Zinc sulfide (30%) and Barium sulfate (70%) with trace amounts of Zinc oxide. Lithopone, first produced in 1874, was called Orr's white. The mixture of the two components is so intimate that it is hard to distinguish microscopically. Lithopone is an inert, transparent pigment which is often used as a filler or as a base for lake pigments. Lithopone was widely used in house paints in the first half of the 20th century. It was also used for some artist grounds, inks and as a filler in Paper, Leather, and Linoleum. Now lithopone has mostly been replaced by Titanium dioxide.

Below 20% substitution, it is recommended to replace 1 kg of TiO2 with 1 kg of Lithopone.  

Titanium dioxide is added to some food packaging to preserve the shelf life of a product.

CSPI’s Chemical Cuisine is the web’s definitive rating of the chemicals used to preserve foods and affect their taste, texture, or appearance. Besides titanium dioxide, the group recommends avoiding artificial sweeteners like aspartame, acesulfame potassium, and sucralose, as well as synthetic food dyes like Yellow 5 and Red 3. CSPI and others have recently asked the Food and Drug Administration to ban the latter dye in foods and ingested drugs because the FDA has already determined that it is a carcinogen unsafe for use in cosmetics.

Why all of a sudden is there so much interest in the safety of Titanium Dioxide?

Researchers from France and Luxembourg gave E171 (the much more food friendly name for Titanium Dioxide) in Europe and the United States, to lab rats in their drinking water for 100 days.

Of those rats, 40 per cent of the exposed rodents developed “preneoplastic lesions” or precancerous growths. The Titanium Dioxide also inhibited the immune systems of the rats and “accelerated” the growth of the lesions. France’s INRA agricultural research institute, which took part in the study, said in a statement.“These results demonstrate a role in initiating and promoting the early stages of colorectal cancer formation,” though it said no conclusion could be drawn about later phases of cancer, or of any danger to humans……….(not till they test it on us!!)

The results of the study were published in the Nature journal Scientific Reports.

Lithopone Market Outlook - 2020–2027

Partial substitution of titanium dioxide in liquid paints 

1345-05-7

The author thanks Marco Leona, Scientist-in-Charge of the Department of Scientific Research at the Metropolitan Museum of Art for conducting fluorescence spectrometry on Wheel of Fortune and a valuable discussion of the research, as well as Silvia Centeno, Research Scientist at the Metropolitan Museum of Art, who performed Raman analysis on the watercolors and also contributed her insight. The phenomenon of the phosphorescing lithopone was originally discovered during the author's fellowship in the Sherman Fairchild Center for the Conservation of Works on Paper, funded by the Andrew W. Mellon Foundation. The author thanks all her colleagues for their ideas and support during the research of this paper, and special thanks to Rachel Mustalish for her assistance in editing this work.

Titanium is a metal element found naturally in the environment. When it's exposed to oxygen in the air, it forms titanium oxides that are contained in many minerals, sands, soils, and dusts.