When last we visited this topic in 2015 through UL Prospector Knowledge Center[i], titanium dioxide was addressed as a pigment very well characterized and notably, the most important hiding pigment for paint. It was also an introductory article, and it was to educate anyone who wanted a general overview of the pigment. It explained that with nano TiO2, due to its ability for self-cleaning, TIO2 was finding use in applications in high-rise buildings for windows. In the last few years, it has been the target of regulation and formulation. Before we address the new topics, some review of the pigment.
Titanium dioxide, is also known as titanium (IV) and is the naturally occurring oxide of titanium, chemical formula TiO2; CI 77891. It has many uses outside of paint, which include food, paper coatings, plastics, cosmetics, printing inks and others. It is also used in cosmetics, food and feedstuff, textiles, rubber and pharmaceuticals. It is primarily obtained from ilmenite, rutile and anatase, but also occurs as brookite
There are two main processes for TiO2: In 1916, the Titanium Pigment Corporation of Niagara Falls, New York and the Titan A/S, of Norway simultaneously began commercial TiO2 production with Sulfate Process. In 1951 DuPont introduced the Chloride Process.
European Union Regulations – February 2020
The European Union has published the regulation to classify titanium dioxide as a suspected carcinogen by inhalation. The European Chemicals Agency’s Committee for Risk Assessment (RAC) announced June 9, 2017, which TiO2, a substance commonly used in paints, construction materials and other industrial and consumer goods, meets the criteria to be classified as a suspected cause of cancer via inhalation, under Category 2. It will be enforced after more than a year of a transition period.
This followed another European country that recommended cancer labeling for TiO2. At the time, French regulators argued that the substance is likely a Category 1B carcinogen, meaning it is known to cause cancer in humans. The French regulatory body ANSES sought “harmonized classification” for the substance across the entire EU.
Many in the coatings industry, including the American Coatings Association, oppose the measure. The ACA issued a statement following the RAC’s 2017 announcement asserting that the recommendation is unfounded. “There is considerable industry concern that the basis for the opinion is flawed and does not inform on risk to humans,” the statement read. “It is important to consider that the risks profiled are not attributable formulated products, like paint, where TiO2 dust is embedded in the mixture.”
The ACA has repeatedly expressed concerns that all paint products containing the substance could be labeled as carcinogens under the EU’s classification system. The Titanium Dioxide Manufacturers Association, which represents the TiO2 industry, has also previously issued a statement expressing its disappointment in the recommendation. As previously noted, TiO2 is used in the food industry, along with powdered sugar in doughnuts and a multitude of other applications. Although Dunkin’ Donuts decided to eliminate the use of powdered TiO2, was it really harmful?
In the past 20 years, nanomaterials have found greater utilization in many applications. This has been true also for TiO2, where the very small particles are very useful in cosmetics as well as catalytic self-cleaning. In cosmetics, the move away from organic ultraviolet absorbers has led to the use of nano-sized zinc oxide (ZnO) and TiO2. Both are highly effective in absorbing UV-sunlight.
“The scientific evidence is clear: There are no grounds for classifying TiO2 as carcinogenic for humans by inhalation,” said Robert Bird, chairman of the TDMA. “Also, classification would do nothing to increase the level of protection of human health and the environment, which is the whole point of the labelling and classification system.”
The REACH Committee of the European Commission met several times to discuss the matter last year, without coming to a majority decision, which put the assessment in the hands of the Commission now in the fall. The EU executive’s 18 July comments to the WTO come in response to US concerns that the proposed requirements “may be unnecessarily disruptive to billions of dollars in US-EU trade”.
The Commission said while substances classified as category 1 carcinogens have the “most significant consequences” such as bans, those listed as category 2 face “no such significant direct consequences”. It added that there would be “no or minor consequences” with regard to legislation on plant protection products, biocidal products, food additives, contaminants, water and pharmaceuticals.
Regarding other legislation, the use of titanium dioxide could continue under certain conditions, such as: an authorization being granted; an exemption; or demonstration of safe use. This, the Commission said, would be the case for plastic food contact materials, toys, cosmetics and the EU Ecolabel.
And it confirmed that only the respirable particles of titanium dioxide – with a diameter smaller than 10µm – will be classified as a suspected carcinogen. It also proposed to introduce a note to limit the classification of mixtures to those placed on the market in powder form with a diameter smaller than 10µm if they contain 1% or more of such particles. Liquid mixtures (for example, paints) as well as solid mixtures will not have to be classified, it said.
For such non-classified mixtures, the Commission is proposing the addition of the following sentence on the label: ‘Warning! Hazardous respirable droplets/dust may be formed when sprayed/used. Do not breathe spay or mist/dust.’
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As stated previously, there are many applications of TiO2, but paint is by far the largest (Figure 1).
Of all white hiding pigments, titanium dioxide, and specifically rutile, affords the best opacity/hiding (Figure 2).
The refractive index (RI) of air is 1.00. The greater the difference between a pigment and RI of air, the greater is the opacity and therefore hiding of the pigment. There are other paint opacifying technologies that leverage this optical effect as well.
TiO2 does possess the highest opacity of paint pigments, but it is a relatively expensive pigment. “Spacers” are used in paint, so that the TiO2 pigment particles are less agglomerated and are more readily amenable to optimum hiding.
As mentioned previously, nano-TiO2 has also found utilization in the remediation of pollutants and deposited materials, on skyscraper windows and other structures not easily accessed. The market for photocatalyst is depicted in Figure 3, while the schematic in Figure 4 represents what occurs.
It will be curious to see what regulations eventually occur that may affect how paint is made. Eliminating titanium dioxide as an ingredient could have devastating effects.
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6 Responses to “Titanium Dioxide: The Misunderstood Pigment”
We are a procurement and tender company with a chain of clients within East and Southern Africa. We are looking for a manufacturer, distributor, or reseller for the following products:
Titanium Dioxide Rutile grade
Please quote the prices in USD for the above with CIF terms to Dar Es Salaam port. Thereafter we shall discuss with our client and then forward to you the details in which you will issue a proforma invoice.
Awaiting your swift response towards establishing a long-term relationship with your prestigious company.
Soft Ventures Limited
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UL Prospector provides information, but is not a sales platform. I suggest you use a search engine for whatever you want to sell, be it Rutile or something else. That should narrow it down some. Any of the big producers would be manufacturing it globally. In the search engine if you just search the country and material, it should give you the name of the company and contact information.
Kindest regards, Marc
As I had indicated earlier (6/21) UL Prospector provides information, but is not a sales platform. I suggest you use a search engine for whatever you want to sell, be it Rutile or something else. That should narrow it down some. Any of the big producers would be manufacturing it globally. In the search engine if you just search the country and material, it should give you the name of the company and contact information.
Kindest regards, Marc
Boa tarde estou a gostar da informação eu estou já no final do meu curso de inspetor de de coating
Gostaria de aprender muito mais
There are many sources of information. The UL articles cover quite a bit. Besides coatings, there are also articles on adhesives, inks, sustainability, etc.