Polychloroprene, applications hoses

Due to its balance of strength, oil resistance, inflammability, increased resistance to ozone, ageing and weathering, polychloroprene finds widespread industrial use. Typical uses are V-belts, conveyor belts, wire and cable jacketing, footwear, wet suit applications, coated fabrics, inflatables, hoses, extrusions and many other goods. Adhesives are also a strong market area. 

Extrusion. Polychloroprene has been employed in a wide variety of extrusion (qv) processes. Intricate cross-sections such as highway compression seals, bulb weather-stripping, and hose represent a few examples. As with calendering, extrusion is very sensitive to nerve. The DuPont Dow neoprene sol/gel blend types are best suited for extrusion applications. Use of low levels of highly structmed furnace carbon blacks, stearic acid, petroleum, paraffin wax, triethanolamine benzoic acid, and calciiun stearate are particularly effective extrusion aids. The screw of the extruder should have a constant diameter root with increasing pitch. Heat history of the compound should be minimized, with only a brief warm-up before extrusion begins. The barrel and screw should be lun cool, 50°C, and the die hot, 95°C (96,119). 

Crystallization is important for some hose manufacturing applications as it imparts some stiffness for braiding. The rapid crystallization of some polychloroprene pol5uners is fully exploited in adhesive manufacture and use (64). 

Polychloroprene rubbers find use in such applications as cable-sheaths, hose and weather strips. Latices are used in the production of dipped goods, such as gloves and balloons, foams, adhesives and corrosion-resistant coatings. 

Frequently, specific applications require a particular type of elastomer [27], For example, a hose should have as large a mismatch of solubility parameters with the fluid it will be transporting. Thus polar elastomers, such as polychloroprene would be best for hoses used with hydrocarbon fluids, such as gasoline, jet fuel, greases, oils, lubricants, etc. 

When selecting the grade of polysulfide to use for a given application the service conditions are the key criteria to consider. Thiokol FA, as previously indicated, is used mainly in covered rolls and specialty hose where its excellent solvent resistance may be needed. It is often blended with other elastomers such as polychloroprene if some sacrifice in solvent resistance can be tolerated, or with a high acrylonitrile NBR if a minimal loss in solvent resistance is dictated. 

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