Chlorosulfonated polyethylene applications

Solvent-home urethanes are still widely used to bond leather and athletic shoes. The OEM automotive market uses some solvent-home urethanes together with chlorosulfonated polyethylene as a primer. Some urethane solvent-home packaging adhesives are used for cap liners and for paper and foil lamination. Some textile laminating applications are still based on solvent-home urethanes. 

The prime installation method is mechanically fastened but fully adhered and ballasted applications can also be used. CSPE exhibits strong resistance not only to weathering but also to a broad range of chemicals and pollutants it is also inherently ozone-resistant. It can be produced in many colors and the sheet widths are typically 5—6.5 ft (1.5—1.65 m). The physical characteristics of a CSPE sheet have been described (17) (see Elastomers, SYNTHETIC—CHLOROSULFONATED POLYETHYLENE). 

The most common polymers used in FR wire and cable applications are PVC, polyolefins, fluoropolymers, and silicone polymers. Thermoplastic polyurethanes (TPUs) and other specialty polymers such as chlorosulfonated polyethylene also serve niche applications in wire and cable. The approaches to achieve flame retardancy in each of these polymer systems along with issues unique to wire and cable application are discussed in the following sections. 

Small amounts of other polymers are used in certain niche applications, including chlorinated polyethylene (CPE), neoprene, chlorosulfonated polyethylene, nylon, and TPU. 

Surface treatments consist of washing with solvent, abrading, or, in the most demanding applications, cyclizing with acid. The most common elastomers to be bonded in this way include nitrile, neoprene, urethane, natural rubber, SBR, and butyl rubber. It is more difficult to achieve good bonds with silicones, fluorocarbons, chlorosulfonated polyethylene, and polyacrylate. 

Ozone-resistant elastomers which have no unsaturation are an excellent choice when their physical properties suit the application, for example, polyacrylates, polysulfides, silicones, polyesters, and chlorosulfonated polyethylene (38). Such polymers are also used where high ozone concentrations are encountered. Elastomers with pendant, but not backbone, unsaturation are likewise ozone-resistant. Elastomers of this type are the ethylene—propylene—diene (EPDM) mbbers, which possess a weathering resistance that is not dependent on environmentally sensitive stabilizers. Other dastomers, such as butyl mbber (HR) with low double-bond content, are fairly resistant to ozone. As unsaturation increases, ozone resistance decreases. Chloroprene mbber (CR) is also quite ozone-resistant. 

The above criteria were employed to select several commercially supplied Class PS elastomers for laboratory screening by employing selected tests taken from National Bureau of Standards NBSIR 77-1437(j4) and ANSI/ASTM D-3667-78 specifications for "Rubber Seals Used in Flat-Plate Solar Collectors". Four silicone, three EPDM, two fluorocarbon, three epichlorohydrin, one ethylene-acrylic, one polyacrylic, one chlorosulfonated polyethylene, one bromobutyl and two butyl rubbers were studied in these screening tests. These materials are identified in Table I and those compositions which were revealed by their manufacturers are shown in Table II. Undoubtedly some materials which should have been included were omitted however, we hope that this sampling will provide an indication of the applicability of a wide range of materials for use as sealants in thermal solar collectors. 

In 1970, DuPont Introduced Hypalon A5, a thermoplastic grade of chlorosulfonated polyethylene synthetic rubber, for applications as a pond liner material. It was one of the first thermoplastic elastomers retaining easy seamablllty both in the fabrication plant and in the field, and possessing outstanding resistance to outdoor weathering. 

As a consequence, before 1953, the only possible blends were those of LDPE with other polymers than PO or with elastomers (e.g., chlorosulfonated polyethylene rubber, CSR chlorinated butyl mbber, CBR ethylene/propylene/diene copolymers, EPR, EPDM thermoplastic olefinic elastomer TPE, TPO). However, in addition to the original autoclave polymerization, already in 1938, a tubular reactor was introduced and its product had different properties than that from the autoclave. Also varying the reaction condition affected the degree of short- and long-chain branching in LDPE thus, blending different LDPEs offered a way for optimizing the resin to specific applications. 

CSM is extensively used in construction and electrical applications. This includes roofing membranes, automotive ignition boots and wires, roll compoimds, and some automotive hoses requiring good heat and oil resistance, eg, air conditioning and power steering hoses. It is also used in nuclear power plants because of its excellent resistance to radiation degradation. Chlorosulfonated polyethylene is sold under the trade name Hypalon. 

Natural rubber/chlorosulfonated polyethylene rubber blends also exhibited immiscibility. Chlorosulfonated polyethylene rubber is the synthetic rubber used for applications in electric cables, hoses for liquid chemicals, waterproof cloths, floor tiles, and oil-resistant seals. It is chosen to blend with natural rubber to improve the resistance of natural rubber to ozone, oil, heat, flame and non-polar chemicals. This is due to the effect of the polarity of the chlorine groups in the chlorosulfonated polyethylene rubber. The tensile strength, elongation at break, and tear strength of these blends decreased with the increasing chlorosulfonated polyethylene rubber contents. In addition, the compatible natural rubber/chlorosulfonated polyethylene rubber blends were improved by adding the epoxidized natural rubber (Epoxyprene 25) as a... 

Chlorosulfonated polyethylene synthetic rubber is manufactured by DuPont under the tradename of Hypalon. In many respects it is similar to neoprene but has better heat and ozone resistance, better electrical properties, and superior weathering resistance. Because of Hypalon s outstanding weathering resistance it is used as an outer protective jacket in high-voltage applications. 

Hypalon is a tradename for CSM chlorosulfonated polyethylene. It offers good resistance to moderate chemicals, ozone, alkaline solutions, hydrogen. Freon, alcohols, aliphatic hydrocarbons, as well as ultraviolet degradation from sunrays. Strong oxidizing acids, ketones, esters, acetic acid, and chlorinated and nitro-hydrocarbons attack Hypalon. Its temperature range for applications is from -40°C to 150°C (-40°F to 300°F). Its physical properties are presented in Table 10-16. 

EPDM successfully competes with other rubbers (butyl, chloroprene, and chlorosulfonated polyethylene) and other materials (PVC, bitumen compounds, and composites), offering quite satisfactory ageing/weathering characteristics associated with good/excellent mechanical properties at a rather low cost. Table 29 illustrates such an application. 

There are other specialty elastomers that can substitute for CPE however, recompounding and reformulating will be required, along with extensive re-evaluations. Chlorosulfonated polyethylene (CSM) is chemically similar to CPE and might partially substitute for CPE in certain applications after going through a technical approval process. 

Similarly, thermoplastic grades of chlorosulfonated polyethylene (CSM), such as Hypalon 45 (DuPont), are sometimes reinforced with PVC in roofing and pond liners. Such blends are also most conveniently mixed in an internal mixer. Often, such blends are formulated to crosslink in service by the reaction of metal oxides with CSM aided by atmospheric moisture. Blends of both CSM and CPE with PVC have also been used in such applications. 

Treatment of polyethylene with chlorosulfonic acid before the application of adhesive enhanced the adhesion of the polymer to itself and to aluminium and natural sponge rubber. ... 

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