Butyl rubber (IIR – isobutylene-isoprene rubber) is a material widely used in the construction, automotive, chemical, and HVAC industries. Its exceptional barrier properties and chemical resistance are well known; however, the behavior of butyl under extreme temperatures remains a key issue for designers and engineers. Below is an analysis based on material research data.
Behavior of butyl at low temperatures (extreme cold)
One of the most important parameters describing elastomer performance at low temperatures is the glass transition temperature (Tg).
For butyl rubber, Tg typically ranges from –65°C to –70°C, as confirmed by DSC (Differential Scanning Calorimetry) studies.
Research findings:
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Down to approximately –40°C, butyl maintains elasticity and vibration-damping capability.
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Below –50°C, a gradual increase in elastic modulus is observed, but without sudden brittleness, which is common in many other elastomers.
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ASTM D746 (Cold Brittleness Temperature) tests indicate that butyl exhibits very good resistance to impact cracking at low temperatures.
Practical significance:
Thanks to these properties, butyl is used in:
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roofing and façade seals in subarctic climates,
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membranes and tapes operating in winter conditions,
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insulation of cryogenic installations (with appropriate formulation modifications).
Behavior of butyl at high temperatures (extreme heat)
High temperatures affect elastomers through:
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relaxation of the polymer network,
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accelerated thermal aging,
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possible migration of additives.
Aging test data (ASTM D573):
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Standard butyl performs stably in the temperature range from –40°C to +100°C.
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In short-term exposure, it can withstand temperatures up to +120°C without loss of sealing performance.
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Under long-term exposure above 100°C, the following are observed:
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a reduction in elongation at break,
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a moderate increase in hardness (Shore A).
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Key advantage:
Butyl exhibits the lowest gas permeability among elastomers, and studies show that this parameter remains stable even at elevated temperatures, which is critical for airtight and sealing applications.
Conclusions based on laboratory data
Based on available laboratory research:
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butyl retains elasticity in extreme cold,
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it does not undergo rapid degradation at high temperatures,
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it offers stable barrier properties across a wide temperature range.
For these reasons, butyl rubber is a material of first choice wherever reliability under extreme climatic conditions is required.