Staining and discoloration

Copper compounds are highly coloured, and a very small amount of corrosion may lead to staining and discoloration of products. 

In 1970, Miyoshi Okamoto, a scientist from Toray Industries, created the first microfiber. A few months later his colleague Toyohiko Hikota developed a process that allowed the production of fabric that was later trademarked as Ultrasuede . Ultrasuede was produced from such thin PET polyester fibers that a pound of them laid end-to-end would reach from the earth to the moon and back. Ultrasuede is soft and supple, resistant to stains and discoloration, and machine-washable and dry-cleanable. 

Ceramic Tile Tile is quite commonly used in toilets and shower areas. It is mentioned here only to note that the case of quarry tile when used in connection with a corrosion resistant grout, the installation will withstand the staining and discolorization so common from exposure to urine (uric acid) and the strong cleaning solutions found in toilet areas. 

Use To remove stains and discoloring after transporting coke and coal cargoes. 

Zabel, R.A., and J.J. Morrel Wood stains and discoloration. In Wood Microbiology. Decay and its prevention. Acad. Press, San Diego, CA, 1992. 

Chemical Antiozonants. The first effective chemical antiozonant was a dihydroquinoline type, l,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline (DETQ). However, polymerised quinoline derivatives provide only slight ozone protection, although they are good antioxidants. DETQ provides protection against the action of ozone, hut it is highly staining and discoloring and is lost from rubber compounds because of its volatility. 

All of these antiozonants are staining and discoloring. This has limited their use primarily to carbon black-loaded compounds. We also note that the antiozonants and amine-based antioxidants cause a reduction in scorch resistance. 

Aromatic amines, normally arylamines, may be more effective than phenolics, but most are staining and discoloring and lack FDA approval for use in contact with food. Amines are commonly used in the rubber industry but also find minor uses in plastics such as black wire and cable formulations and in polyurethane polyols. 

All PPDs are highly staining and discoloring. This behavior is not necessarily a problem in carbon black filled articles, but restricts usage in colored goods—or even tires with colored components. 

Vulkanox 4010 NA/LG is a staining and discoloring antiozonant and antioxidant protecting rubber goods against ozone attack, oxidation, heat aging, flexcracking and rubber poisons. It is suitable for natural and synthetic rubbers. 

Vulkanox 4010 NA/LG antiozoneuit excels in antiflexcracking properties and is used in tires and mechanical goods subjected to dyneunic stress, e.g. conveyor belts, hoses, spring components and elastic couplings. In static applications and in cables and seals, its main function is resistance to ozone cracking, which can be further improved by the simultaneous use of an ozone protective wax. Use should be restricted to dark colored rubber articles where staining and discoloration are of no concern. 

Vulkanox HS is an antioxidant with relatively weak staining and discoloration characteristics, it provides outstanding heat protection in natural rubber (MR), synthetic polyisoprene (IR), polybutadiene (BR), styrene butadiene rubber (SBR), nitrile rubber (NBR) and ethylene propylene rubber (EPIBl), but is less suited>le for polychloroprene (CR). Its performance is improved further in combination with Vulkanox MB-2 antioxidant, which is especially effective in thiuram cured articles with low levels or sulfur or without sulfur. Vulkanox HS antioxidant also yields good protection against rubber poisons. 

When the staining and discoloration of PPDs cannot be tolerated (e.g., white sidewalls) ozone protection is obtained by adding ozone-resistant polymers. These work by relieving stress and inhibitting crack propagation 30 phr or more of polymer is usually required. 

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