These agents are hydrophobic in nature because of their chemical composition. In simpler words, the solubility of these OBAs is quite low. As the name suggests, these brighteners are made by four sulphonic groups. This type of brightening agents exhibit medium affinity and good solubility.
As we all have experienced, clothes lose their natural whiteness over the course of time. And in fabrics sourced from animalsimpurities like animal fats, secretions, etc.
The raw material of paper often consists of impurities such as snippets of bamboo sticks and wood. Unlike the above-mentioned industries, these industries make the use of the brightening property of brighteners.
Questions about skin reactions have also been raised, and many studies have shown no sensitization; however, one study that did patch testing noted no sensitivity occurred unless UV light or "abrasive action" was used. So it seems that there is a potential for problems if you wear clothes impregnated with optical brighteners in natural sunlight. A study done by the Environmental Protection Agency EPA back in questioned the environmental and health effects of optical brighteners. They noted that over 29,, lbs.
Today the EPA's DFE program invites laundry formulators to partner with them to act as environmental stewards by making products that are more eco-friendly. For optical brighteners, the program encourages manufacturers to use those that pose "low toxicity to humans and the environment both as parent chemicals and degradation byproducts. Optical brighteners aren't readily biodegradable and may bioaccumulate, so they pose a potential hazard to aquatic life. Also, according to a report by the European Ecolabel Commission on criteria for laundry detergents, as optical brighteners undergo photodegradation, numerous metabolites may be produced that are not yet identified, which means we may not know the true potential impacts upon the environment.
Given these questions regarding environmental effects and the huge amounts of these chemicals being used today, it seems wise to cut back on our usage of them when we can. Start by voting with your pocketbook and not buying laundry detergents with optical brighteners! Soaking clothing in lemon juice and water before laundering and then hanging them out to line dry in the sun works like a charm. Hydrogen peroxide and water solution can work too. Another eco-friendly solution is to purchase one of the many non-chlorine oxygen-based bleaches on the market, such as Seventh Generation's Natural Oxy Stain Remover.
Belsito, Donald V. Elsevier BV , doi Actively scan device characteristics for identification. Bleaching has both of these effects to some extent but invariably leaves behind part of the yellowish cast.
Even the most thorough bleach cannot remove all traces of a yellowish cast. These dyes absorb light in the green-yellow region of the spectrum, thereby reducing lightness.
But, since at the same time they shift the shade of the yellowish material towards blue, the human eye perceives an increase of whiteness.
0コメント