Neoprene CR

Neoprene is one of the oldest and most versatile of the synthetic rubbers. Chemically, it is polychloroprene. Its basic unit is a chlorinated butadiene whose formula is 

The raw material is acetylene which makes this product more expensive than some of the other elastomeric materials. 

Neoprene was introduced commercially by DuPont in 1932 as an oil-resistant substitute for natural rubber. Its dynamic properties are very similar to those of natural rubber, but its range of chemical resistance overcomes many of the shortcomings of natural rubber. 

As with other elastomeric materials, neoprene is available in a variety of formulations. Depending on the compounding procedure, material can be produced to impart specific properties to meet specific application needs. 

Neoprene is also available in a variety of forms. In addition to a neoprene latex that is similar to natural rubber latex, neoprene is produced in a fluid form as either a compounded latex dispersion or a solvent solution. Once these materials have solidified or cured, they have the same physical and chemical properties as the solid or cellular forms. 

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CNR = Grey Areas PP = White Areas Neoprene (CR) = Dark Areas... 

Neoprene, or polychloroprene rubber (CR) was one of the very first synthetic rubbers produced. It was a material of choice for exterior applications such as profiles used in vehicles, building seals, and cables. Many more marketable products have benefited from this plastic. Except for SBR and IR, neoprene (CR) elastomers are perhaps the most rubberlike of all materials, particularly with regard to its dynamic response (Table 2.6). CRs are a family of elastomers with a property profile that approaches that of NRs (natural rubbers) but has better resistance to oils, ozone, oxidation, and flame. CRs age better and do not soften up on exposure to heat, although their high-temperature tensile strength may be lower than that of NRs. They are suitable for service at 250C (480F). 

Rubber Blends For Automotive Applications. The ionomers from Exxpro elastomer can be blended with other elastomers such as Neoprene(CR), Nitrile(NBR), and Acrylics(VAMAC) for selected automotive applications, e.g., hoses, air springs, and belts. 

L nsaturafed poh ester (UP) Neoprene (CR) Polyisoprene OR) Polyurethane elastomers (PU)... 

Examples of vulcanizable elastomers include natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), ethylene-propylene-diene monomer-rubber (EPDM), butyl rubber (HR), polychloroprene or neoprene (CR), epichlorohydrin rubber (ECO), polyacrylate rubber (ACM), millable polyurethane rubber, silicone rubber, and flu-oroelastomers. Examples of thermoplastic elastomers include thermoplastic polyurethane elastomers, styrenic thermoplastic elastomers, polyolefin-based thermoplastic elastomers, thermoplastic polyether-ester (copolyester) elastomers, and thermoplastic elastomers based on polyamides. 

Neoprene (CR) (chloroprene) was the first synthetic elastomer and is widely used in industry. It is nonflammable and has some resistance to oils. 

Several elastomers can be used in rubber-based adhesives. The elastomer provides the backbone of the adhesive, so the main performance of the adhesive is provided by the rubber properties. However, several specific properties for application are imparted by adding other ingredients in the formulations. The most common elastomers used in rubber-based adhesives are natural rubber (NR), butyl rubber (BR) and polyisobutylenes, styrene-butadiene rubber (SBR), nitrile rubber (NBR) and polychloroprene rubber Neoprene) (CR). 

ENR prepared from chemical modification of NR latex has recently been commercialized. ENR was claimed to have oil resistance property, low gas permeability and more anti-oxidizing and damping than NR. Up to now, many research works have studied its applications and their blends with other polymers such as in this case, the blend between ENR and neoprene (CR) of which the effect of blending ratio on processability of ENR/CR blend was studied by Chiu et al Mastication of ENR (ENR-50, Malaysian Rubber Producers Research Association), CR (ES-2-16K, Du Pont), vulcanizing agent, accelerator, and other related ingredients was carried out in a pressurized kneader (SYD-5, Star-King Enterprise Co., Taiwan) for 17 min under a rotation rate of 77 rpm. Each sample s composition was listed in Table 18.7. 

Other Names Neoprenes CR, GR-M Butyl, HR, GR-I ThiokolS PS, GR-P AdipreneS PU... 

Chloroprene Neoprene (CR) 100-800 50 to 105 (60 to 225) Excellent ozone, heat, and weathering resistance good oil resistance excellent flame resistance not as good in electrical applications as natural rubber Wire and cable chemical tank linings belts, hoses, seals, and gaskets... 

Elastomers containing polyepichlorohydrin, also known as ECO, CO, or GECO according to ASTM, offer an excellent balance of properties, combining certain desired dynamic properties of namral mbber (NR), with much of the fuel, oil, and chemical resistance of other specialty elastomers such as nitrile (NBR), polyacrylate (ACM), and neoprene (CR) mbbers. The combination of the basic properties of oil, fuel, heat, low-temperature flexibility, and ozone resistance imparted by the saturated main chain and the chlorine groups, coupled with low permeability, makes polyepichlorohydrin a very useful elastomer for automotive applications. Specific applications include fuel hoses, emission tubing, air ducts, seals, and diaphragms. 

Polysulhdes often are blended with other elastomers such as nitrile rubber, NBR, or neoprene, CR, for improved physical properties and factory processing. Traditionally, Thiokol FA is blended with neoprene for improved strength and processing for rollers, at some sacrihce in solvent resistance. Table 11.9 has information on Thiokol FA blends. If minimal loss in chemical resistance is indicated, then a blend with a high ACN nitrile is employed. A cure system that is compatible with both rubbers needs to be used in all cases. The zinc peroxide-cure system is NBR specihc, hence it is important that the recommended one be used or others be tested since many NBRs do not cure with zinc peroxide. Best results are obtained with blends if separate masterbatches are made with the individual polymers, which are then blended in the... 

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