Rubber Hypalon

The chemical name for Hypalon is chlorosulfonated polyethylene and it has excellent resistance to heat, ozone and oxidising chemicals and has good abrasion resistance. It can be compounded for outstanding resistance to oxidising chemicals, such as sodium hypochlorite solutions in sulfuric acid saturated with chlorine and concentrated phosphoric acid. It is one of the few synthetic rubbers that can be mixed in any colour without loss in mechanical properties. 

The uncured Hypalon compound behaves much like a thermoplastic resin. It is tough and nervy at room temperature, but its viscosity is reduced rapidly as it is warmed by working on a two roll mill. By contrast Neoprene is not as tough as Hypalon at lower temperatures. 

---

Commercial grades contain 25 to 43 percent chlorine and 0.8 to 1.5 percent sulfur randomly distributed along the polymer chains. Cnre rates increase with increases in chloro-sulfonation. Grades with low chlorine content (25 percent) are best for heat resistance and optimum electrical resistivity. Flame resistance increases with chlorine content. CSM was commercialized by Dn Pont as Hypalon rubber. 

Kilpikari I (1982) Occupational contact dermatitis among rubber workers. Contact Dermatitis 8 359-362 Kilpikari I, Halme H (1983) Contact allergy to Hypalon rubber. Contact Dermatitis 9 529... 

Kaidbey KH, Kligman AM (1974) A human model of coal tar acne. Arch Dermatol 109 212-215 Kanerva L, Henriks-Eckerman ML, Jolanki R, et al. (1997) Plastics/acrylics material safety data sheets need to be improved. Clin Dermatol 15 533-546 Kilpikari I, Halme H (1983) Contact allergy to Hypalon rubber. Contact Dermatitis 9 529... 

Chloropropyl, vinyl, and methacrylate-functional silanes on glass were only slightly better than untreated surface for adhesion to most of the rubbers. The mercaptan and amine-functional silanes have been the preferred silanes on fillers in sulfur-vulcanized rubbers. The amine gave better adhesion to natural, nitrile, and Hypalon rubbers, while the mercaptan was better with SBR, Neoprene and EPDM. The iso-thiuronium-functional silane appears to be fairly effective in bonding all rubbers—but especially SBR. Anionic or cationic styryl coupling agents were the best unsaturated silanes and contributed true adhesion to EPDM and Hypalon. 

Reactive fluids (DuPont) Methyl methacrylate, Hypalon rubber, dihydropyridine and hydroperoxide Impact resistance, ability to bond oily metals and wide range of plastics. Very volatile, flammable and high odour... 

Low-volatile systems (Loctite) High-molecular-weight monomer, non-Hypalon rubber, dihydropyridine and hydroperoxide Low volatile, low flammability, fast fixture and able to bond side range of materials... 

Footnotes (a) Gaskets are also available in other materials, such as hydrogenated nitrile, neoprene, butyl rubber, hypalon, silicon rubber to meet various application requirrnents. (b) Viton is a Du Pont Co. trademark for a series of fluoroelastotners based on the copolymer ofvinylidene fluoride and hexafluoropropylene. 

The molded liners for the inlet head, cylinder section, and conical sections have Integral molded gaskets for sealing at the flanged joints. Molded liners and vulcanized linings are offered in gum rubber, polyurethane, nitrile rubber, butyl. Neoprene , Viton , Hypalon , and other liner materials can be supplied. 

The construction materials for the plates include most corrosion-resistant metals, usually 304SS, 316SS, titanium, Incoloy 825 , Hastelloy , and others, plus nonmetallic fused graphite, and fluoroplastic Diabon F . Typical gaskets between the plates include nitrile rubber, butyl, and EPDM elastromers, Hypalon and Viton , based on the various manufacturers literature. 

Chlorosulphonated polyethylene rubber (Hypalon) has excellent chemical resistance even to oxidative acids at elevated temperatures. When specially compounded it can have excellent abrasion resistance in some operating conditions. 

When two polymers interact or react with each other, they are likely to provide a compatible, even a miscible, blend. Epoxidized natural rubber (ENR) interacts with chloro-sulfonated polyethylene (Hypalon) and polyvinyl chloride (PVC) forming partially miscible and miscible blends, respectively, due to the reaction between chlorosulfonic acid group and chlorine with epoxy group of ENR. Chiu et al. have studied the blends of chlorinated polyethylene (CR) with ENR at blend ratios of 75 25, 50 50, and 25 75, as well as pure rubbers using sulfur (Sg), 2-mercapto-benzothiazole, and 2-benzothiazole disulfide as vulcanizing agents [32]. They have studied Mooney viscosity, scorch... 

Synthetic rubbers are also used for particular applications. Hypalon (trademark, E. I. du Pont de Nemours) has a good resistance to strongly oxidising chemicals and can be used with nitric acid. It is unsuitable for use with chlorinated solvents. Viton (trademark, E. I. du Pont de Nemours) has a better resistance to solvents, including chlorinated solvents, than other rubbers. Both Hypalon and Viton are expensive, compared with other synthetic, and natural, rubbers. 

The EVAs make it possible to produce compounds with high filler levels and are compatible with many elastomers, plastics and other materials SBR, butyl rubber, EPDM, nitrile rubber, Hypalon, thermoplastic elastomers, epoxies, PVC, PVDC, bitumen. 

Hypalon chlorosulfonated polyethylene was introduced by Du Pont in 1952. Although not a high volume rubber it has found use in coatings and hoses. 

Certain types of synthetic rubbers such as neoprenes and hypalons when suitably compounded with asbestos fillers are flame resistant and give passive fire protection. This safety aspect is a key priority in many chemical and engineering industries as well. These fire protection technologies are used to protect structures and equipment against all types of fires including the extreme conditions of a jet fire. 

Exterior surface corrosion or rusting of pipes occurs by the formation of iron oxides. Painting to an appropriate specification will significantly extend the period to the onset of corrosion, but the durability of the paint finish is largely dependent on the quality of the surface preparation as well as the thickness of the coated film. Improperly installed insulation can provide ideal conditions for corrosion and should be weatherproofed or otherwise protected from moisture and spills to avoid contact of the wet material on equipment surfaces. Application of an impervious coating such as bitumen to the exterior of the pipes is beneficial in some circumstances. Hypalon and neoprene rubber-based anticorrosive coatings admixed with chlorinated rubber are finding use in many installations. 

Chemicals, Chlor alkali. Paper and pulp, Fertilizers, Oil drilling and Pharmaceu ticals Chemical resistant linings for storage tanks, road and ship tankers, process vessels, pipelines, valves, pumps, filters, agitators, centrifuges, impellers, etc. Soft natural rubber or ebonite, neoprene, butyl and hypalon depending on operating temperature, and application. 

Water and Effluent Treatment in Nuclear and other chemical plants. Corrosion resistant linings for water treatment vessels and pipelines, pumps, valves, flowmeters, agitators, chemical dosing tanks, effluent tanks etc. Soft natural rubber or ebonite, EPDM, butyl, neoprene or hypalon. 

Ethylene-propylene rubber Fluoro-rubber Hypalon Natural rubber Neoprene rubber Nitrile rubber Polysulphide rubber Polyurethane rubber Silicone rubber Styrene-butadiene rubber (SBR)... 

E I du Pont Nemours Co Elastomer Chemicals Dept, Wilmington Delaware, USA, R M Murray and D C Thompson, The Neoprenes, Formal Reports-Basic Principles of Compounding, Informal reports-Basic Details of Compounding and Test data, Hypalon Reports, Viton Bulletins, Adiprene Bulletins and Extensive reports on various Specialty Rubbers. 

The areas where a test piece is attached to clamps and cut edges are preferential sites for cracking. It is generally good practice to coat clamped areas with an ozone resistant paint (which does not affect the rubber in any way) but cut edges are best left. For most purposes a Hypalon-based paint is satisfactory. Clamps, even when made of material such as aluminium, should be soaked in ozone prior to use. Any pattern or flaws on the test piece surface will also tend to act as stress raisers and show preferential cracking. 

Synthetic membrane liners Polyvinyl chloride, butyl rubber, Hypalon, polyethylene, nylon-reinforced liners Expensive may be justified where gas is to be recovered. 

---