Protective polyurethane chemicals

Tertiary Amine Catalysts. The Hquid tertiary aHphatic amines used as catalysts in the manufacture of polyurethanes can cause contact dermatitis and severe damage to the eye. Inhalation can produce moderate to severe irritation of the upper respiratory tracts and the lungs. Ventilation, protective clothing, and safety glasses are mandatory when handling these chemicals. 

Elastomeric Fibers. Elastomeric fibers are polyurethanes combiaed with other nonelastic fibers to produce fabrics with controlled elasticity (see Fibers, elastomeric). Processing chemicals must be carefully selected to protect all fibers present ia the blend. Prior to scouriag, the fabrics are normally steamed to relax uneven tensions placed on the fibers duriag weaving. Scouriag, which is used to remove lubricants and siting, is normally conducted with aqueous solutions of synthetic detergents and tetrasodium pyrophosphate, with aqueous emulsions of perchloroethylene or with mineral spidts and sodium pyrophosphate. 

Eastern Research Group and Syracuse Research Corporation (2005) Furniture Flame Retardancy Partnership Environmental Profiles of Chemical Flame-Retardant Additives for Low-Density Polyurethane Foam. United States Environmental Protection Agency, EPA 742-R-05-002A. 

U S Environmental Protection Agency (2005) Environmental profiles of chemical flame-retardant alternatives for low-density polyurethane foam. In Furniture Flame Retardancy Partnership, US... 

Elastomeric Fibers. Elastomeric fibers are polyurethanes combined with other nonelastic fibers to produce fabrics with controlled elasticity. See also Fibers Elastomeric. Processing chemicals must be carefully selected to protect all fibers present in the blend. 

Because of the low surface energy, resistance to chemicals and corrosive agents, and resistance to weathering, fluorinated polyurethanes are very well suited for protective coatings. They can be deposited in a desired location and thickness with the added advantage of curing mostly at ambient temperatures. 

There are numerous types of paint employed in the protection of steel and they are designed to meet the conditions imposed by the environment in which they are expected to function. For steel exposed to the atmosphere, the most common type of paint system is based on alkyl resin and this may be mixed with other types or may itself be chemically modified for a specific purpose, e.g. vinyl toluenated or styrenated to give rapid drying. Other generic types are chlorinated rubber, vinyl, acrylic, epoxy, and polyurethane. All have particular attributes and limitations and selection is usually a matter of discussion between user and supplier. 

Spandex-type polyurethane fibers are chemically quite stable under normal washing and chlorine containing swimming pool water conditions. Special stabilizers are required for protection against ultraviolet radiation, suntan lotions, human perspiration, etc. 

Thus, to eliminate or minimize chemical adhesion the metal mold surfaces must be protected from polar materials such as polyurethanes by an interface which not only avoids the physical problems of adhesion, but those which are of a reactive chemical nature as well, i.e., a non-wetable, non-polar, non-reactive boundry layer or film. In terms of releasibility, therefore, such a boundry between the metal mold surface and the polyurethane must be present. It makes no difference whether this is achieved by the application of an external mold release (EMR) agent, or though the incorporation of an internal mold release (IMR) agent. 

Phosgene, unfortunately, retains the reputation of being a very unpleasant chemical, due to its early use as a war gas. Whilst undeniably toxic, like its precursors carbon monoxide and chlorine, it can be simply contained and easily converted into harmless added-value products, which contribute to our quality of life. Today we may consider it fully redeemed by its widespread use as an intermediate for producing the ubiquitous and useful polyurethanes, as well as contributing on a lesser scale as a reagent for s)mthesis of a number of valuable pharmaceuticals and crop protection agents. 

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