Butyl rubbers abrasion resistance

Butyl rubber, halogenated butyl rubber linings and ethylene propylene rubber linings have excellent chemical resistance at temperatures up to 120°C. There are cases where butyl rubber linings have been subjected to temperatures down to —65°C without deterioration. Linings based on these polymers do not exhibit good abrasion resistance, which can only be rated as fair. 

Butyl Rubber. A synthetic rubber produced by copolymerization of isobutene(98%) with a small proportion(ca 2%) of isoprene or butadiene. Polymerization is conducted at-50 to 100° in a liquid hydrocarbon, with A1C13 as catalyst. Its outstanding property compared with other rubbers is impermeability to gases. The uncured rubber is tacky, but it may be compounded like natural rubber and vulcanized. Butyl rubber has good resistance to chemical attack and to aging even at high temps. It has superior vibration insulation characteristics and abrasion resistance, but relatively low tensile strength and poor flame resistance... 

The latexes upon which this industry developed were natural rubber and polychloroprene for solvent resistance. However, technology is advancing to permit penetration of carboxylated nitrile latex for optimized solvent resistance and tougher abrasion resistance. Among the competition to latexes in this field are poly(vinyl chloride) plastisols. As technology develops in producing small particle size latexes from polymers whose synthesis is loo water-sensitive for emulsion polymerization, the dipped goods industry will quickly convert to their utilization from the solvent-based cements of these polymers now employed Prime candidates include butyl rubber, EPDM, hypalon, and vlton. 

Butyl Rubber Gloves—Provide protection from nitric acid, sulfuric acid, hydrofluoric acid, red fuming nitric acid, rocket fuels, and peroxide. These gloves have a high impermeability to gases, chemicals, and water vapor, and resistance to oxidation and ozone attack. They have high abrasion resistance and remain flexible at low temperatures. 

The first use for butyl rubber was as inner tubes, whose air-retention characteristics contributed significantly to the safety and convenience of tires. Good weathering, ozone resistance, and oxidative stability have led to applications in mechanical goods and elastomeric sheeting. Automobile tires were manufactin-ed for a brief period from butyl rubber, but poor abrasion resistance cimtailed this development. 

The single outstanding physical property of butyl rubber is its impermeability. Its abrasion resistance, tear resistance, and adhesion to fabrics and metals is good. The flame resistance of butyl rubber is poor. Table 4.7 lists the physical and mechanical properties of butyl rubber. 

EPDM has a generally acceptable resistance to most moderate chemicals, alcohol, ozone, and organic acids. It is, however, attacked by strong acids, solvents, most hydrocarbons, chloroform, and aromatic solvents. The minimum temperature for use is -51°C (-60°F) and its maximum temperature is 177°C or 350°F. FPDM offers better abrasion resistance than butyl rubber. It is also used as a high-temperature gasket. Mechanical properties are presented in Table 10-13. 

Promoters perform an important function in the heat treatment of mixtures of butyl rubbers with fillers. Compounds based on the heat treated mixtures have better extrusion and calendering properties than they would have otherwise and their vulcanisates have greater resilience, elasticity, flexibility, abrasion resistance, and electrical resistivity. Various promoters have been withdrawn from the market recently as potential health hazards, but a dispersion of poly-dinitrosobenzene in inert filler, now marketed by Hughson Chemical as PolyDNB, is still available. 

Butyl rubber vulcanisates are characteristically strong, tough and tear resistant, and have ample abrasion resistance for applications in which butyl rubbers are normally used. Highly reinforcing carbon blacks and heat treatment contribute to optimum results. 

Resin curing of SBR and BR imparts excellent cut growth and abrasion resistance. Resin cured nitrile rubber shows high fatigue life and high relaxation, while resin-cured butyl rubber shows outstanding ozone and age resistance (409). 

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