Melamine: Difference between revisions
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Animal studies have shown that ingestion of large amounts of melamine monomer may lead to [[kidney stone]]s, [[cancer]] or [[reproduction|reproductive damage]].<ref>[http://www.cdc.gov/niosh/ipcsneng/neng1154.html International Chemical Safety Card]</ref><ref>[http://ptcl.chem.ox.ac.uk/MSDS/ME/melamine.html MSDS]</ref><ref>[http://www.osha.gov/dts/chemicalsampling/data/CH_250440.html OSHA] – Chemical sampling information</ref><ref>[http://monographs.iarc.fr/ENG/Monographs/vol73/volume73.pdf WHO] – Some Chemicals that Cause Tumors of the Kidney or Urinary Bladder in Rodents and Some Other Substances</ref> Melamine polymers used in household products are less reactive than melamine monomer and are not known to be toxic in humans. |
Animal studies have shown that ingestion of large amounts of melamine monomer may lead to [[kidney stone]]s, [[cancer]] or [[reproduction|reproductive damage]].<ref>[http://www.cdc.gov/niosh/ipcsneng/neng1154.html International Chemical Safety Card]</ref><ref>[http://ptcl.chem.ox.ac.uk/MSDS/ME/melamine.html MSDS]</ref><ref>[http://www.osha.gov/dts/chemicalsampling/data/CH_250440.html OSHA] – Chemical sampling information</ref><ref>[http://monographs.iarc.fr/ENG/Monographs/vol73/volume73.pdf WHO] – Some Chemicals that Cause Tumors of the Kidney or Urinary Bladder in Rodents and Some Other Substances</ref> Melamine polymers used in household products are less reactive than melamine monomer and are not known to be toxic in humans. |
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In 2007 there was a recall by [[Menu Foods]] of pet foods due to suspected contamination. On 30 March 2007, the US [[Food and Drug Administration]] reported finding melamine in the recalled pet food, in samples of [[wheat gluten]] imported from China used in the production of the food, as well as in crystalline form in the kidneys and in urine of affected animals. The cooking required in the preparation of |
In 2007 there was a recall by [[Menu Foods]] of pet foods due to suspected contamination. On 30 March 2007, the US [[Food and Drug Administration]] reported finding melamine in the recalled pet food, in samples of [[wheat gluten]] imported from China used in the production of the food, as well as in crystalline form in the kidneys and in urine of affected animals. The cooking required in the preparation of pet food products containing melamine removes the nitrogen and leaves ammonia, a poison and guanidine, a muscle stimulant sold as a pharmaceutical. |
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The presence of the compound has not been conclusively linked to the deaths of animals. Note this was melamine monomer not melamine polymer used in household products. <ref>[http://www.fda.gov/ora/fiars/ora_import_ia9926.html US FDA "Import Alert" for Wheat Gluten containing melamine]</ref> |
The presence of the compound has not been conclusively linked to the deaths of animals. Note this was melamine monomer not melamine polymer used in household products. <ref>[http://www.fda.gov/ora/fiars/ora_import_ia9926.html US FDA "Import Alert" for Wheat Gluten containing melamine]</ref> |
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Revision as of 04:10, 5 April 2007
Melamine is a strong organic base with the chemical formula C3H6N6, with the IUPAC name 1,3,5-triazine-2,4,6-triamine. It is produced from urea, mainly by either of two methods: catalyzed gas-phase production or high pressure liquid-phase production.
Melamine, dicyandiamide (or cyanoguanidine) and cyanamide are related. The first is considered the trimer and the second the dimer of the third. All contain 66% nitrogen and provide fire retardant properties to resin formulas by releasing nitrogen when burned or charred.
Uses
Melamine is used to produce melamine resin, which when combined with formaldehyde produces a very durable thermosetting plastic. This plastic is often used in kitchen utensils or plates (e.g. Melmac) and is the main constituent in high pressure laminates such as Formica and Arborite and of laminate flooring. Melamine tile wall panels can also be used as whiteboards. Melamine resin is often directly laminated onto particle board; the resultant panel is often referred to just as "melamine" and is frequently used in ready-to-assemble furniture and inexpensive kitchen cabinets.
With up to 6 active hydrogen sites, melamine reacts with formaldehyde and methanol to form a large family of resins. A resin ratio of 2 moles formaldehyde to 1 mole of melamine is used extensively to impregnate countertop surface paper laminates, making them flame and boil resistant. A resin ratio of 6 moles of formaldehyde to 1 of melamine followed by excess methanol forms a methylolated cross-linked resin used to impart heat and solvent resistance to numerous thermoset coatings. Hydroxy functional resins are crosslinked by reaction with methylolated melamines often in the presence of an acid catalyst. Frequently these coatings are cured by oven baking. Their rapid curing makes them ideal for finishes applied when the product is manufactured, often to protect metal. Thermoset acrylics and polyester coatings are commonly formulated with melamine crosslinkers. As with other amino resins, the crosslinks can be hydrolyzed in the presence of acid. Hence, inadequate resistance to bird droppings and tree sap has been a deficiency in applications like automotive finishes. There crosslinkers such as blocked isocyanates are used advantageously.
Another polymeric material obtained from melamine is melamine foam, a foam-like material used as a cleaning agent and a laminating material. When melamine was reacted to create the foam it lost its nitrogen-release property[citation needed].
Melamine is only slightly soluble in water. Melamine polymer does not have the same properties as melamine monomer. Melamine use as a fertilizer in China is totally misplaced since it is not soluble in water and nitrogen would only be released if a heat source were present.
Toxicity
Animal studies have shown that ingestion of large amounts of melamine monomer may lead to kidney stones, cancer or reproductive damage.[1][2][3][4] Melamine polymers used in household products are less reactive than melamine monomer and are not known to be toxic in humans.
In 2007 there was a recall by Menu Foods of pet foods due to suspected contamination. On 30 March 2007, the US Food and Drug Administration reported finding melamine in the recalled pet food, in samples of wheat gluten imported from China used in the production of the food, as well as in crystalline form in the kidneys and in urine of affected animals. The cooking required in the preparation of pet food products containing melamine removes the nitrogen and leaves ammonia, a poison and guanidine, a muscle stimulant sold as a pharmaceutical.
The presence of the compound has not been conclusively linked to the deaths of animals. Note this was melamine monomer not melamine polymer used in household products. [5]
Melamine is produced from the heating of dicyanodiamide which is prepared from the polymerization of cyanamide. Aside from dicyanodiamide being used in the production of melamine it is also used in the production of barbiturates and in guanidine derivatives.
See also
References
- ^ International Chemical Safety Card
- ^ MSDS
- ^ OSHA – Chemical sampling information
- ^ WHO – Some Chemicals that Cause Tumors of the Kidney or Urinary Bladder in Rodents and Some Other Substances
- ^ US FDA "Import Alert" for Wheat Gluten containing melamine