As EXXON Bromobutyl and EXXON Chlorobutyl both contain the predominantly saturated backbone of Butyl, these polymers have many of the attributes of the Butyl polymers:

• Low permeability to air, gases and moisture
• Vibration damping
• Low glass transition temperature
• Resistance to ageing and to weathering from atmospheric exposure
• Wide vulcanization versatility
• Fast cure rates
• Processing safety: no nitrosamines or nitrosamines precursors

Halobutyls display additional covulcanization with general purpose high-unsaturation elastomers, like natural rubber, polybutadiene, and styrene-butadiene rubber, while maintaining the mostly saturated backbone structure.

EXXON Bromobutyl and EXXON Chlorobutyl standard 75 lb. bales are provided with either of these wraps:

• EVA: Inclusion film. Melting Point @ 93 to 96°C
• RFU: Blue colored Removable Film Unit or strippable film

  Chemical Resistance Guide

EXXON Bromobutyl Polymers

EXXON Bromobutyl is structurally similar to EXXON Chlorobutyl and, like Chlorobutyl it has a broader vulcanization latitude than butyl due to its reactive functionality.

In relation to Chlorobutyl, Bromobutyl provides an additional level of crosslinking reactivity based upon its lower C-Br bond energy, compared to the C-Cl bond. This results in compounds with faster cure rates that can utilize a wider assortment of curative systems. As a result, Bromobutyl provides an even higher level of co-curing compatibility with general purpose elastomers than Chlorobutyl.

	Mooney Viscosity	Cure Rate
EXXON™ BROMOBUTYL 2211 EVA	32±5	Fast
EXXON BROMOBUTYL 2222 EVA	32±5	Regular
EXXON BROMOBUTYL 2244 EVA	46±5	Fast
EXXON BROMOBUTYL 2255 EVA	46±5	Regular

EXXON Chlorobutyl Polymers

Chlorobutyl can be vulcanized with certain curative systems to provide improved properties at elevated temperatures in comparison to Butyl. It also enables a degree of covulcanization with general purpose rubbers which Butyl cannot achieve.

Due to the relative reactivity of carbon-halogen bonds, Chlorobutyl reacts more slowly than Bromobutyl, so it possesses a more predictive cure response with additional scorch and processing safety, and less sensitivity to mixing, processing, and storage conditions.

	Mooney Viscosity
EXXON CHLOROBUTYL 1066 EVA	38±5
EXXON CHLOROBUTYL 1066 RFU	38±5
EXXON CHLOROBUTYL 1068 EVA	50±5

EXXON is a trademark of ExxonMobil Chemical Corporation.