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

• 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

The 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 RFU	Low	Fast
EXXON BROMOBUTYL 2222 EVA	Low	Regular
EXXON BROMOBUTYL 2255 RFU	High	Regular

Click to view EXXON Bromobutyl Polymers web page


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	Medium
EXXON CHLOROBUTYL 1066 RFU	Medium
EXXON CHLOROBUTYL 1068 RFU	High

Click to view EXXON Chlorobutyl web page.

EXXON is a trademark of ExxonMobil Chemical Corporation.