Polychloroprene, applications

Latex Adhesive Applications. Polychloroprene latex adhesives have a long history of use in foil laminating adhesives, facing adhesives, and constmction mastics. Increasingly stringent restrictions on the emission of photoreactive solvents has heightened interest in latex compounds for broader apphcations, particularly contact bond adhesives. Table 10 makes a general comparison of solvent and latex contact bond adhesives (158). 

The applications of polysulphide rubbers are due to their excellent oil and water resistance and their impermeability to gases. Because of other factors, including their unpleasant odour, particularly during processing, they are much less used than the two major oil-resistant synthetic rubbers, the polychloroprenes and the nitrile rubbers. 

Structural applications of rubber base adhesives were also obtained using rubber-thermosetting resin blends, which provided high strength and low creep. The most common formulations contain phenolic resins and polychloroprene or nitrile rubber, and always need vulcanization. 

During World War II, polychloroprene was chosen as a replacement for natural rubber because of its availability. Two copolymers of chloroprene and sulphur which contain thiuram disulphide were available (Neoprene GN and CG). One of the first successful applications of these polychloroprene adhesives was for temporary and permanent sole attachment in the shoe industry. However, these polychloroprene cements show a decrease in viscosity on ageing and a black discolouration appears during storage in steel drums. Discolouration was produced by trace amounts of hydrochloric acid produced by oxidation of polychloroprene... 

Butyl phenolic resin is a typical tackifier for solvent-borne polychloroprene adhesives. For these adhesives, rosin esters and coumarone-indene resins can also be used. For nitrile rubber adhesives, hydrogenated rosins and coumarone-indene resins can be used. For particular applications of both polychloroprene and nitrile rubber adhesives, chlorinated rubber can be added. Styrene-butadiene rubber adhesives use rosins, coumarone-indene, pinene-based resins and other aromatic resins. 

Fig. 25. Evolution of the tack of polychloroprene-aromatic hydrocarbon resin blends as a function of the resin content. Tack was obtained as the immediate T-peel strength of joints produced with 0.6 mm thick styrene-butadiene rubber strips placed in contact without application of pressure. Peeling rate = 10 cm/min.

Applications of solvent-borne CR adhesives and polychloroprene latices will be considered separately. 

The use of plasticisers, with other than PVC applications, is extensive. Many polar rubber sealants or caulking materials are plasticised in order to make them more pliable, e.g., polysulfides, polychloroprene (Neoprene ), nitrile rubber. Esters, similar to those employed with PVC, are used to render cellulose diacetate ("Acetate") overhead projection sheets more flexible. 

The chlorine atom also confers an increased level of resistance to oils, so that the oil resistance of polychloroprene is roughly intermediate between natural rubber and nitrile rubber, and is often sufficient for many applications. Polychloroprene is also self-extinguishing in flame tests. 

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. 

Colloidal particles, foams used to collect and separate, 12 22 Colloidal powders, 23 55-56 Colloidal silica, 22 380, 382, 384 applications of, 22 394 modification of, 22 393-394 preparation of, 22 392-393 properties of, 22 391-392 purification of, 22 393 Colloidal silica gels, 23 60 Colloidal solids, 7 293-294 Colloidal stability, 7 286-291 10 116 22 55 Colloidal stabilizers, in polychloroprene latex compounding, 19 857 Colloid mills, 8 702 10 127 Colloids, 7 271-303 23 54. See also Polymer colloids analysis, 7 296 applications, 7 292-296 conducting, 7 524... 

Polychloroprene latex adhesives, 1 533-534 Polychloroprene latexes, 19 854-861 applications for, 19 857, 859-861 compounding, 19 857-859 global product line of, 19 855 stabilization of, 19 855-857 Polychloroprene polymers branching parameters of, 19 839 commercial, 19 851-852 crystallization of, 19 843-844 cure site for, 19 837... 

Chloroprene Elastomers. Polychloroprene is a polymer of 2-chloro-1,3-butadiene. The elastomer is largely composed of the trans isomer. There are two basic polymer types the W-type and the G-type. G-types are made by using a sulfur-modified process W-types use no sulfur modification. As a result, G-types possess excellent processing and dynamic properties, and tend to be used in V-belts. However, they have poorer aging properties than W-types. The W-types tend to be used in applications requiring better aging, such as rolls and mechanical goods (see Elastomers,... 

SEALANTS. Any organic substance that is soft enough to pour or extrude and is capable of subsequent hardening to fonn a permanent bond with the substrate. Most sealants are synthetic polymers (silicones, urethanes, acrylics, polychloroprene) that are semisolid before application and later become elastomeric. 

Ethylenethiourea has a wide variety of uses in addition to vulcanization, a principal application since 1948. The curing process converts most of the ETU to other compounds, but traces of it are still found in the rubbers. Neoprene (polychloroprene) is found largely in automotive parts, wire and cable insulation, construction and adhesives. Consumer products containing neoprenes include container seals (e.g., aerosol dispensers) and shoes. It is also an intermediate in the manufacture of antioxidants, dyes, fungicides, insecticides, pharmaceuticals, synthetic resins, and a constituent of plating baths. 

Fig. 10.27 Devolatilization of a 42% polychloroprene-58% CCI4 in a JSW TEX 65 counter rotating, intermeshing TSE. (a) The effect of increasing the number of vent ports at Q = 30 kg/h and N = 125 rpm. (b) The effect of decreasing Q/N ratio, at constant Q. [Reprinted by permission from T. Sakai and N. Hashimoto, Application of Novel Counter-rotating Intermeshed Twin Extruder for a Degasing Operation. SPE ANTEC Tech Papers, 32, 860 (1986).]...

Development of polybutadiene, polychloroprene and especially copolymers of butadiene andstyrene, as best replacements for natural rubber for tire-applications. Sodium used as catalyst Ring-opening polycondensation of caprolactam discovered by Schlack Formulation of the well-known Mark-Houwink equation for the viscometric determination of the molecular weight (mass)... 

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). 

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