Elastomers polychloroprene

Chemistry of polychloroprene rubber. Polychloroprene elastomers are produced by free-radical emulsion polymerization of the 2-chloro-1,3-butadiene monomer. The monomer is prepared by either addition of hydrogen chloride to monovinyl acetylene or by the vapour phase chlorination of butadiene at 290-300°C. This latter process was developed in 1960 and produces a mixture of 3,4-dichlorobut-l-ene and 1,4-dichlorobut-2-ene, which has to be dehydrochlorinated with alkali to produce chloroprene. 

Although there are several manufacturers of polychloroprene elastomers, Du Pont probably has the broader range of polychloroprene grades on the market. As an example in Table 3, the equivalencies between the peptizables sulphur-modified and stabilized with thiuram disulphide polychloroprenes are given... 

Several types of polychloroprene elastomers have been commercialized. The most important polymers used in solvent-borne adhesives are the following. 

Formulation of a solvent-borne CR. A typical formulation of a solvent-borne CR adhesive may include the following components (fillers are not commonly added and curing agents are added to improve heat resistance) (1) polychloroprene elastomer (2) metal oxides (3) resins (4) antioxidants (5) solvents (6) fillers (7) curing agents (8) other modifiers. 

Polychloroprene elastomer. Neoprene AC and AD are the most commonly used, mainly Neoprene AD because of its superior viscosity stability. For difficult-to-bond substrates, graft polymers Neoprene AD-G or AF) show better performance. For sprayable adhesives or high-viscosity mastics, the Neoprene AG offers excellent results. When specific properties (e.g. increase tack, improve wetting, increase peel strength) need to be met, blends of Neoprene AC or AD with Neoprene AG provide adequate performance. 

Poly(methyl methacrylate) (PMMA) plastics Polychloroprene elastomer (Neoprene Carothers)... 

Elastomers, synthetic-polychloroprene Elastomers, synthetic-ethylene-propylene-diene rubber). Tires, hoses, bdts, molded and extmded goods, and asphalt products consume ca 80% of the redaimed mbber manufactured. Typical properties of reclaimed mbbers are shown in Table 5. 

Chloroprene is a monomer used almost exclusively for the production of polychloroprene elastomers and latexes. It readily forms dimers and oxidizes at room temperature. Occupational exposures occur in the polymerization of chloroprene and possibly in the manufacture of products from polychloroprene latexes. 

Elastomers, synthetic -acrylic elastomers [ELASTOMERS, SYNTHETIC - ACRYLIC ELASTOMERS] (Vol 8) -butyl rubber [ELASTOMERS, SYNTHETIC - BUTYL RUBBER] (Vol 8) -chlorosulfonated polyethylene [ELASTOMERS, SYNTHETIC - CHLOROSULFONATED POLYETHYLENE] (Vol 8) -ethylene-acrylic elastomers [ELASTOMERS, SYNTHETIC - ETHYLENE-ACRYLIC ELASTOMERS] (Vol 8) -ethylene-propylene-diene rubber [ELASTOMERS,SYNTHETTC - ETHYLENE-PROPYLENE-DIENE RUBBER] (Vol 8) -fluorocarbon elastomers [ELASTOMERS, SYNTHETIC - FLUOROCARBON ELASTOMERS] (Vol 8) -nitrile rubber [ELASTOMERS, SYNTHETIC - NITRILE RUBBER] (Vol 8) -phosphazenes [ELASTOMERS, SYNTHETIC - PHOSPHAZENES] (Vol 8) -polybutadiene [ELASTOMERS, SYNTHETIC - POLYBUTADIENE] (Vol 8) -polychloroprene [ELASTOMERS, SYNTHETIC - POLYCHLOROPRENE] (Vol 8) -polyethers (ELASTOMERS, SYNTHETIC - POLYETHERS] (Vol 8) -polyisoprene [ELASTOMERSSYNTHETTC - POLYISOPRENE] (Vol 9) -survey [ELASTOMERS, SYNTHETIC - SURVEY] (Vol 8)... 

While there are significant differences between grades of polychloroprene elastomers due to molecular weight differences and crystallinity characteristics, by and large, processing and performance properties may include ... 

Uses Accelerator for polychloroprene elastomers, halobutyl rubbers esp. chlorobutyl used for mech. goods, cables, hoses, membranes, fabric proofings, vulcanizing sol ns. 

Baypren/Bystal Polychloroprene elastomers Bayer AG/Miles... 

Polychloroprene elastomer Although grades Neoprene AC and are the most commonly used, the latter is more prevalent because of its superior viscosity stability. 

Principal uses include automotive V-belts, industrial and hydraulic hoses, specialty roofing, heels and soles in footwear, wire covering, and a wide variety of coated fabric uses, eg, rafts. Polychloroprene elastomers are also used extensively in adhesives. It is estimated that about 77,000 ton of polychloroprene are used each year in the United States (4,7,19). 

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. 

K. J. Kim et al. [54, 55] showed effects of various processing additives in halogen atom-containing elastomer compounds including polychloroprene elastomer (CR) and fluoro-... 

Polychloroprene elastomers are produced by free radical emulsion polymerization of 2-chloro-l,3-butadiene monomer. The emulsion polymerization of chloroprene involves the dispersing of monomer droplets in an aqueous phase by means of suitable surface active agents, generally at a pH of 10-12. Polymerization is initiated by addition of free radical catalyst at 20-50° C. To obtain a bigb conversion in the polymerization reaction and processable polymer, the addition of sulfur, thiuram disulfide, or mercaptans is necessary (Whitehouse 1986). 

Influence of solvent on viscosity and tack of polychloroprene adhesives. Formulation 100 phr polychloroprene elastomer 4 phr MgO 5 phr ZnO 2 phr hindered phenolic antioxidant 500 phr solvents mixture (Whitehouse 1986)... 

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