What is Butyl Rubber

Butyl rubber vulcanizates are highly coveted due to their remarkable impermeability to air and moisture, effective damping of low-frequency vibrations, and robust resistance to aging, heat, acids, bases, ozone, and various chemicals.

Regular butyl rubber (IIR) is a copolymer of isobutylene and a small fraction of isoprene (0.5 – 2.5 mol%). The incorporation of isoprene into the polymer chain provides unsaturation, allowing the rubber to be vulcanized. The unique densely packed structure of butyl rubber results in exceptional impermeability to gases, a defining characteristic of this polymer class.

IIR finds extensive applications, including tire inner tubes, tire curing envelopes and bladders, adhesives, sealants, tank linings, and even chewing gum.

Halogenation of IIR in an aliphatic solvent using chlorine (Cl2) or bromine (Br2) produces chlorobutyl (CIIR) and bromobutyl (BIIR) rubber, respectively. This process enhances co-vulcanization and compatibility with other diene rubber types, improving vulcanization rates, states of cure, and reversion resistance. Halogenated butyl rubber is widely used in tire inner liners, hoses, seals, membranes, and is the preferred choice for medical stoppers due to its cleanliness and excellent resealing properties.

The Airtight Advantage:

The outstanding air retention properties of butyl rubber make it the preferred material for tire inner liners and inner tubes. Its low permeability to gases, moisture, and liquids helps maintain optimal tire pressure, reduces steel belting corrosion, minimizes oxidation of other tire components, and ensures consistent performance over time. This translates to improved efficiency, safety, and extended tire life.

Unique Attributes for Non-Tire Applications:

Butyl rubber’s unique attributes, including low permeability and compatibility with clean cure systems, enable widespread use in non-tire applications, especially in the medical and pharmaceutical sectors. It is commonly used for stoppers in infusion containers, injection vials, and blood collection tubes. Halogenated butyl rubber is preferred for ensuring the adequate protection of sterile pharmaceutical products against external contamination during storage, secure delivery, and use.

Meeting Stringent Standards in the Food Industry:

With heightened quality control requirements in the food industry, certified-grade butyl rubber aligns with stringent regulations and standards. This material is the preferred choice for manufacturing chewing gum bases. The exceptional stability and resistance to aging ensure that stick gum packaged by your favorite brands remains soft during shelf storage, preserving its enjoyable texture when you’re ready to indulge.