Foamed elastomer

The amine groups thus formed can also react vigorously with the isocyanate groups to continue the chain extension and cross-linking reactions. Hence, ia the systems there are simultaneous foaming, polymerization, and cross-linking reactions, which produce foam elastomers (or plastics). 

Oxidisable organic materials of high surface to volume ratio (carbon powder, foamed elastomers, lampblack, sawdust) react very violently, even at -78°C, with perchloryl fluoride, which should be handled with the same precautions as liquid oxygen. 

Used industrially to manufacture polyurethane foams, elastomers, coatings used as a cross-linking agent. 

Toluene diisocyanate is commonly produced as a mixture of the 2,4- and 2,6-iso-niers, that is used as a monomer in the preparation of polyurethane foams, elastomers and coatings, as a cross-linking agent for nylon-6, and as a hardener in polyurethane adhesives and finishes. Polyurethane elastomers made from toluene diisocyanates are used in coated fabrics and clay-pipe seals. Polyurethane coatings made from toluene diisocyanates are used in floor finishes, wood finishes and sealers, and in coatings for aircraft, tank trucks, truck trailers and truck fleets (United States National Library of Medicine, 1997). 

According to the 1981-83 National Occupational Exposure Survey (NOES, 1997), approximately 40 000 workers in the United States were potentially exposed to toluene diisocyanates (see General Remarks). Occupational exposures to toluene diisocyanates may occur during their production and in the production of polyurethane foams, elastomers, coatings, adhesives and finishes. Exposure may also occur in the use of some polyurethane products. Data on occupational exposure levels have been presented in a previous monograph (lARC, 1986). More recent exposure levels have been reported in connection with epidemiological (Section 2) and toxicological (Section 4) studies. 

MW 174.16 CAS [584-84-9] used in the production of urethane foams, elastomers, and coatings also commercially available as a mixture of 2,4- and 2,6-isomers colorless liquid or solid turns dark on exposure to light pungent fruity odor boils at 238°C melts at 20.5°C (80 20 mixture of the isomers melts at 13°C) density 1.22 g/mL decomposes with water and alcohol soluble in most organic solvents highly toxic. 

Toluene Diisocyanate (TDI) Toluene diisocyanates (2,4- and 2,6 isomers) are produced from toluene diamine derived from dinitrotoluene, which is produced by the nitration of toluene with nitric/sulfuric acid mixtures. TDI is used to make flexible polyurethane foams, elastomers and coatings. 

Figure 4.2 Structure of silicones (a) silicone fluid (Dow Coming 360 Medical Fluid) (b) silicone foam elastomer (c) silicone elastomer (vulcanized Silastic 382 Medicalgrade Elastomer) and (d) silicone elastomer (vulcanized Silastic Medical Adhesive Type A)...

Oil- and water-resistant textile finishes Rigid insulating foams Elastomers... 

Pluracol [BASF], TM for a series of organic compounds used in hydraulic brake and other functional fluids, chemical intermediates, urethane foams, elastomers, and coatings. 

Use Polyurethane foams, elastomers and coatings, cross-linking agent for nylon 6. 

Flexible Foam Rigid Foam Elastomers Surface Coatings Adhesives Sealants... 

Applications Coating, lacquers Flexible foams, elastomers Elastomer, prepolymers, synthetic leather Flexible foams, lacquers, coatings... 

Tolnene-2,4-diisocyanate is one of the most extensively used isocyanates. It is nsed in the production of rigid and flexible urethane foams, elastomers, and coatings. In addition to its nse as a pure compound, it is commercially available as a mixture of... 

Polyurethanes are widely used in several important applications including foams, elastomers, coatings, and adhesives. They result from the reaction between an alcohol and an isocyanate, and from this reaction, hyperbranched polymers can also be prepared from AB2 monomers having both functional groups in the proper ratio. The high reactivity of isocyanates, even in self-condensation, can lead to the formation of dimer or carbamates by reaction with... 

Polyurethanes are used in four principal types of products foams, elastomers, fibers, and coatings. The majority of polyurethane is used as rigid or flexible foams. However, about 15% is used for elastomer applications. Production of polyurethane elastomers involves a number of steps. As indicated above, an intermediate hydroxyl-terminated low-molecular-weight polyester or polyether is prepared. This intermediate is reacted with an isocyanate to form a prepolymer (macrodiisocyanate). The prepolymers are coupled or vulcanized by adding a diol or diamine ... 

Major polyurethane products today include cellular materials such as water-blown flexible foams or fluorocarbon-blown rigid foams, elastomers, coatings, and elastic fibers, which are described subsequently. Closely related to polyurethanes is an isocyanate-based product called isocyanurate foam. 

Polyurethanes (PU or PUR) and polyureas are classified as TS resins, but their chemistry is so flexible that they can be formulated different ways. There are moldable solid and expanded TSs, with (RPUR) or without reinforcement, flexible and rigid foams, elastomers and thermoplastic molding compounds. As RPs they are important in reinforced reaction injection molding (RRIM) (Chapter 5) and are also available as reinforced thermoplastic molding compounds. A variant on the process employs a structural preform of the reinforcement that is placed in the mold cavity and is called structural reaction injection molding (SRIM). 

Chem. Descrip. High purity adipic acid CAS 124-04-9 EINECS/ELINCS 204-673-3 Uses Chem. intermediate used in adhesives, coatings (all, PU, gel coat, polyester), nylon 66, PU foams/elastomers/fibers, unsat. polyester resins, lubricants, textile treatments cosmetic emollients wet str. paper resins food acidulant plasticizer pH buffer (water-sol. polymers, flue gas desulfurization)... 

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