Polychloroprene rubber plasticizers

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). 

Chem. Descrip. Triphenyl phosphate CAS 115-86-6 EINECS/ELINCS 204-112-2 Uses Rame retardant platinizing agent, plastidzer tor collodion cotton plastidzer w/o gelatinizing properties for acetyl cellulose reduces tiamm. ot NC and acetyl cellulose-based plastic compds. and lacquer films flame retardant plasticizer tor photographic film materials, surf, coatings, phenolic laminates, cellulose acetate film/compds., rubber articles made from acrylonitrile-butadiene, polychloroprene rubber Features Not compat. with PVC... 

Hypalon is a close match to neoprene in most properties, but it is superior in resistance to acids, solvent, ozone and oxidation, and has decidedly better color stability. This rubber can be used instead of polychloroprene or plasticized polyvinyl chloride in many applications. 

Other polymers used in the PSA industry include synthetic polyisoprenes and polybutadienes, styrene-butadiene rubbers, butadiene-acrylonitrile rubbers, polychloroprenes, and some polyisobutylenes. With the exception of pure polyisobutylenes, these polymer backbones retain some unsaturation, which makes them susceptible to oxidation and UV degradation. The rubbers require compounding with tackifiers and, if desired, plasticizers or oils to make them tacky. To improve performance and to make them more processible, diene-based polymers are typically compounded with additional stabilizers, chemical crosslinkers, and solvents for coating. Emulsion polymerized styrene butadiene rubbers (SBRs) are a common basis for PSA formulation [121]. The tackified SBR PSAs show improved cohesive strength as the Mooney viscosity and percent bound styrene in the rubber increases. The peel performance typically is best with 24—40% bound styrene in the rubber. To increase adhesion to polar surfaces, carboxylated SBRs have been used for PSA formulation. Blends of SBR and natural rubber are commonly used to improve long-term stability of the adhesives. 

Chlorinated rubber is also used to promote the adhesion of solvent-borne CR adhesives to metals and plasticized PVC. Addition of a low molecular weight chlorinated rubber (containing about 65 wt% chlorine) improves the shear strength and creep resistance of polychloroprene adhesives [75] but a reduction in open time is also produced. A heat reactivation (process in which the surface of the adhesive film is raised to 90-100°C to destroy the crystallinity of the film and allowing diffusion to produce polymer chain interlocking more rapidly) restores tack to the polychloroprene adhesives. 

The costs, as for all plastics, fluctuate highly with the crude oil price. Most common TPE/PVCs are cheaper than SEES, TPVs and general-purpose cured rubbers such as EPDMs and polychloroprenes but are more expensive than TPOs and SES. 

In Table 8.4 we see that most butadiene is polymerized either by itself or with styrene or acrylonitrile. The most important synthetic elastomer is styrene-butadiene rubber (SBR). SBR, along with polybutadiene, has its biggest market in automobile tires. Specialty elastomers are polychloroprene and nitrile rubber, and an important plastic is acrylonitrile/butadiene/styrene (ABS) terpolymer. Butadiene is made into adiponitrile, which is converted into hexamethylenediamine (HMDA), on of the monomers for nylon. 

Berlin and coworkers (5,56) desired to obtain a material with an increased mechanical strength. They carried out a plasticization of bulk ami emulsion polystyrene molecular weight 80000 and 200000 respectively at 150-160° C, with polyisobutylene, butyl rubber, polychloroprene, polybutadiene, styrene rubber (SKS-30) and nitrile rubber (SKN 18 and SKN 40). The best results were obtained with the blends polystyrene-styrene rubber and polystyrene-nitrile rubber. An increase of rubber content above 20-25% was not useful, as the strength properties were lowered. An increase in the content of the polar comonomer, acrylonitrile, prevents the reaction with polystyrene and decreases the probability of macroradical combination. This feature lowers the strength, see Fig. 14. It was also observed that certain dyes acts as macroradical acceptors, due to the mobile atoms of hydrogen of halogens in the dye, AX ... 

Polymerization of dienes to form substitutes for rubber was the forerunner of the enormous present-day plastics industry. Polychloroprene (Neoprene, Duprene) was the first commercially successful rubber substitute in the United States. 

Elastomers include natural rubber (polyisoprene), synthetic polyisoprene, styrene-butadiene rubbers, butyl rubber (isobutylene-isoprene), polybutadiene, ethylene-propylene-diene (EPDM), neoprene (polychloroprene), acrylonitrile-butadiene rubbers, polysulfide rubbers, polyurethane rubbers, crosslinked polyethylene rubber and polynorbomene rubbers. Typically in elastomer mixing the elastomer is mixed with other additives such as carbon black, fillers, oils/plasticizers and accelerators/antioxidants. 

MAJOR USES Used in the manufacture of carbon tetrachloride, trichloroethylene, chlorinated hydrocarbons, polychloroprene, polyvinylchloride, hydrogen chloride, hypochlorous acid, ethylene dichloride, metallic chlorides, chlorobenzene, chloroacetic acid, chlorinated lime, chloroform Used in the manufacturing process of water purification, flame retardant compounds, paper products, textiles, petroleum products, medicines, antiseptics, insecticides, solvents, paints, plastics, disinfectants, synthetic rubber. 

Uses Plasticizer for polychloroprene and other polymers resin extender, plasticizer improving water, chem., oil, and gas resist, in traffic paints, protective coatings EP agent in metalworking fluids flame retardant for resins, air filters, plasticized PVC, rubber incl. neoprene, PU, textiles, paints, adhesives... 

A key result of the early crack growth studies was the "critical stress" effect, i.e., no crack growth occurs unless a specific stress value is exceeded. In practical terms these stress values correspond to threshold tensile strains of 3-5%, depending on stiffness. It has been found that critical stress values are largely unchanged by temperature, plasticization, and ozone concentration. Polychloroprene has a higher critical stress value than other diene rubbers, consistent with its reduced reactivity to ozone. 

The Swiss company, WW Fischer, offers PTFE (Teflon PTFE or Hostaflon), PBT (Celanex, Crastin, Ultradur or Valox) or PEEK (Victrex) insulator material options in its 405 series of cylindrical connectors according to the requirements of working temperature and other criteria. PEEK is an expensive polymer which tends to be employed when other materials fail to meet the specification requirements of the application. Other Fischer connector types use polyamide-imide (Torlon) or POM (Celcon, Delrin or Hostaform). Elastomeric seals used by Fischer in conjunction with their connectors are made from acrylonitrile-butadiene rubber (NBR N BUNA) or to MIL-P-25732, fluoroelastomer (FPM VITON), polychloroprene elastomer (CR Neoprene), ethylene-propylene diene elastomer (EPDM) and styrene-ethylene-butadiene-styrene thermoplastic elastomer (TPE-S or TPE-O) where each compound is followed by its trade name. Fischer s Swiss competitor, Lemo, manufactures a similar range of connectors including the Redel types which have a plastic body. 

Nitrile rubber is used preferably for contact adhesives with improved plasticizer resistance. Polyisobutylene is used in pressure-sensitive adhesives. Butyl rubber is sometimes added to pressure-sensitive and hot-melt adhesives, although it is mainly used in sealing compounds. Epoxy resins and reactive (meth)acrylate adhesives (reactive adhesives) are modified with polychloroprene, butyl, and nitrile rubber. Chlorinated rubber is added in small quantities to contact adhesives and also to rubber-to-metal bonding agents for improving the adhesion properties. 

Contact cements based on nitrile rubber and polyurethane are more resistant to oils and plasticizers than polychloroprene adhesives. To improve adhesion and to increase thermal stability, contact adhesives may be applied together with isocyanate hardeners. Today solvent-free contact adhesives based on aqueous polychloroprene latexes are also available. 

More important and with better properties are the cold-setting, two-component acrylate adhesives, which contain methacrylates or acrylates, sometimes mixed with styrene and methacrylic acid as monomer and, in addition, various polymers. The polymers used are primarily synthetic rubbers, such as polychloroprene, styrene-butadiene rubber, butyl rubber, polystyrene, polymethacrylates, and acrylate graft polymers of these polymers. Amines are used as accelerators, and benzoyl peroxide in the form of plasticizer pastes or a powder mixture with fillers is preferred as hardener [43]. 

Most contact adhesives contain a solvent and have a formulation tiiat combines a base of synthetic rubber such as polychloroprene or polystyrene-butadiene with reactive phenolic resins and metal oxides. In addition, there are also transparent types based on polyurethane which provide excellent bonding results for soft plastics such as plasticized PVC (used in many household articles). Recently, a solvent-fi-ee generation of contact adhesives, e.g, based on acrylate, has entered the market. This type can be used to bond solvent-sensitive materials such as polystyrene foam. 

Many rubbers and elastomers are comprised of long hydrocarbon segments, and thus can accept petroleum oils and other predominately hydrocarbon products for use as plasticizer or extenders. These products are available at a significantly lower cost than the synthetic ester plasticizers. Phthalates and adipates of linear alcohols are used to enhance low temperature properties of certain rubber applications, which cannot be met using the hydrocarbon extenders. Polar elastomers such as nitrile rubber and polychloroprene have low compatibility with hydrocarbons and require more polar products such as phthalates or adipates. 

One major problem with the availability of polychloroprene in the recent past has been the availability of butadiene monomer. Because of the gradual switchover from naphtha feedstocks from petroleum to ethane feedstocks from natural gas in the production of ethylene for the plastics industry, there are fewer C4 streams available for butadiene production. Ethylene plants are gaining significant economic savings by making this feedstock conversion from naphtha to ethane. This has resulted in significant shortages of butadiene to the rubber industry. However, there is optimism now that butadiene will be more available than before because... 

In the rubber Industry, DOP is needed for use as a plasticizer in compounds based on polar elastomers such as nitrile rubber or polychloroprene. Since DOP is a polar plasticizer, it is compatible with polar elastomers. If a nonpolar plasticizer such as... 

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