lead paint or lead-based paint is a lead-containing paint. As pigment, lead (II) chromate (Pb Cr O 4 , "yellow chrome"), Lead (II, IV) oxide, (Pb 3 O 4 , "red lead"), and lead (II) carbonate (Pb CO 3 , "white lead") is the most common form. Dust is added to the paint to speed drying, increase durability, maintain fresh appearance, and retain moisture that causes corrosion. This is one of the major health and environmental hazards associated with paint. In some countries, lead continues to be added to paint destined for domestic use, whereas countries like the US and UK have regulations that prohibit this, although lead paint may still be found on old painted properties before the introduction of the rule. Although lead has been banned from household paint in the United States since 1978, the paint used in road markings may still contain it. Alternatives such as water-based and lead-free water paint are readily available, and many federal states and agencies have changed their purchase contract to buy this instead.
Video Lead paint
Histori
White lead was being produced during the 4th century BC; this process is described by Pliny the Elder, Vitruvius and the ancient Greek author Theophrastus.
Traditional methods of making pigments are called heap processes. Hundreds or thousands of pottery pots containing vinegar and tin are grown in layers of brown skin or cow dung. The pots are designed so that the vinegar and lead are in separate compartments, but they are in contact with vapor vinegar. The lead is usually rolled into a spiral, and placed on the ledge inside the pot. The pot is covered with a tin box, which allows carbon dioxide formed by fermenting bark or dirt to circulate in pots. Each layer of pot is covered by a new layer of tan, then another layer of pot. the heat created by fermentation, acetic acid vapor and carbon dioxide in the pile do their work, and within a month the tin coils are covered with white tin crust. The crust is separated from tin, washed and ground for pigment. This is a very dangerous process for the workers. Medieval texts warn of the dangers of epilepsy and epilepsy from working with white lead.
Despite the risks, pigments are very popular among artists because of their density and opacity; a small amount can cover a large surface. It was widely used by artists until the 19th century, when it was replaced by white zinc and white titanium.
The dangers of lead paint were considered established at the beginning of the 20th century. In the July 1904 edition of his monthly publication, Sherwin-Williams reported the dangers of lead paint, noting that a French expert has considered tin paint "toxic in great extent, both to workers and to residents painted with lead colors". In early 1886, German health legislation prohibited women and children from working in factories processing leaded lead and lead sugar.
Maps Lead paint
Toxicity
Lead paint is dangerous. May cause damage to the nervous system, dwarf growth, kidney damage, and delayed development. This is dangerous for children because it tastes sweet, therefore encouraging children to put lead chips and toys with lead dust in their mouths. Lead paint is harmful to adults and can cause reproductive problems in men or women. Decreased sperm production in men has been noted. Lead is considered a possible and possibly carcinogen. High levels can cause death.
Rule
The EU has passed the directive directive directive lead paint.
In Canada, the regulation was first enacted under the Dangerous Products Act of 1976 that limits the lead content of paints and other liquid coatings on furniture, household products, children's products, and the exterior and interior surfaces of each frequently visited building by children up to 0.5% by weight. The new regulations on surface coating materials, which came into effect in 2005, are increasingly limiting the background levels for both interior and exterior paint being sold to consumers. Canadian paint manufacturers have adapted to this level of background in their interior and exterior consumer paints since 1991. However, the Canadian company, Dominion Color Corporation, is "the world's largest lead-based paint pigment manufacturer" and has faced public criticism. to obtain permission from the European Chemicals Agency to continue to export lead tin chromate from its subsidiaries in the Netherlands to countries where its use is not strictly regulated.
The United States Consumer Product Safety Commission (CPSC) banned lead paint in 1977 in residential and public buildings (16 CFR 1303), along with toys and furniture containing lead paint. The reasons cited are "to reduce the risk of lead poisoning in children who may ingest chips or stripping the skin". For producers, the CPSC instituted a Consumer Product Enhancement Improvement Act of 2008, which changed the lead content limit of paint from 0.06% to 0.009% starting August 14, 2009.
In April 2010, the US Environmental Protection Agency required all renovation workers working in homes built before 1978 and harassing more than six square meters of lead paint within the home or 20 square feet outside the home would be certified. Renovation of Regulations, Improvements, and Rules of EPA Rules (RRP Rule) lowers the risk of lead contamination from home renovation activities. This requires companies to renovate, repair and paint projects that disturb lead-based paints at home, childcare facilities and pre-schools (every facility occupied by children) built before 1978 are certified by the EPA and use certified renovation engineers trained by the EPA approved training providers to follow safe working practices.
By 2018, there are about 37 million homes and apartments with lead paint in the United States.
The Philippines prohibits lead pain in 2013 but by 2017 15% of the paint is still not certified.
Lead paint is not banned in India. A 2015 study found that over 31% of household paint in India has lead concentrations above 10,000 parts per million (ppm), which far exceeds the BIS 90 ppm standard for lead in paint.
Leading paint in art
Oil paint
In art, white lead paint is known as "flake white" or "Cremnitz white". It is assessed for ease of handling and lead resistance to oil paint. The dry white lead paint is relatively quick to form a strong and flexible paint film. White-based lead is one of the oldest artificial pigments. It was the only white pigment available to artists in considerable numbers until the twentieth century, when zinc-white and titanium-white became available. Industrial tin-produced white metal, a typical pigment from the nineteenth century to its ban, is considered lower than traditionally made forms, which have larger "flake" particles that facilitate handling.
Titanium and white zinc are much more toxic than lead and most have replaced them in most art applications. Security regulations have also made white tin more expensive and hard to obtain in some areas, such as the European Union. However, lead white oil paint is still produced and used by artists who prefer their unique handling, blending, and structural qualities.
White flakes have many disadvantages, including the tendency to become transparent over time. It also blackens the presence of certain atmospheric pollutants, although this can be reversed.
Water-based paint
Lead is not a traditional pigment in aqueous media, because zinc is superior to working on paper, such as calcium hydroxide (dead lime) for frescos. Lead-based paint, when used on paper, often causes the work to change color over a long period of time; The primary carbonate of the paint reacts with hydrogen sulfide in the air and with acids, which often come from fingerprints.
Substitute
Titanium
The paint manufacturer has replaced lead with a less toxic substitute, white titanium (based on titanium dioxide pigment), which was first used in paint in the 19th century. Titanium dioxide is considered safe enough to be used as a food dye and toothpaste. It is also a common ingredient in sunscreen. When used in paint today, it is often coated with silicone or aluminum oxide for durability. White titanium has a much larger opacity and color strength than pale white, and can easily defeat most other pigments if not carefully mixed. White titanium has been criticized for causing "chalkiness" in the mix, and for allegedly lowering the immortality of organic pigments mixed with it because of its high refractive index.
Zinc
The white zinc is less opaque and weaker in staining strength compared to white titanium or white tin. This is usually used to lighten the mixture subtly while maintaining transparency. Although white zinc is the standard white color in watercolor, its structural strength in oil has been disputed. The white zinc dries slowly and creates a relatively inflexible paint film. Critics of pigments argue that their use causes excessive cracking and delamination, even when used sparingly.
See also
- Environmental issues with paint
- Lead-based paint in the United Kingdom
- Lead-based paint in the United States
- Lead tetroxide
References
Bibliography
- Rutherford J. Gettens; Hermann KÃÆ'¼hn; W. T. Chase (1967). "Identification of Painting Materials: White Lead". Study in Conservation . 12 (4): 125-139. JSTORÃ, 1505410.
- Ball, Philip (2001). Bright Earth Art and Color Discovery . Penguin Group. ISBN: 9782754105033. Gifford, Donald G (2010). Claims the Tobacco and Lead Pigments Industry: Government Litigation as a Public Health Recipe . Ann Arbor: University of Michigan Press. ISBN: 978-0-472-11714-7.
- Thomson, Daniel (1956). Medieval Painting Materials and Techniques . Dover Publication. ISBNÃ, 0-486-20327-1.
External links
- EPA guides for leading safety
- National Pollutant Inventory (Australia) - Leads and leads multiple fact sheets
- National Lead and Allergen Surveys in Housing
- Bibliography annotated by paint and color
- Myths about lead paint
Source of the article : Wikipedia
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