Ionomers
(Ethylene Acrylic Acid Copolymers, EAA, EMAA, tie Resins)

Properties and Applications

Ionomers are transparent thermoplastic elastomers of glass-like clarity that consist of both electrically neutral and ionized groups that are randomly and / or regularly distributed along the polymer backbone. The ion content is usually no more than 10 to 15% and, thus, most ionomers are insoluble or only slightly soluble in water. At low temperatures they behave like crosslinked polymers (elastomers) and at elevated temperatures like ordinary thermoplastics.

The by far most important ionomers are ethylene acrylic acid (EAA) and ethylene methacrylic acid copolymer (EMAA) and their salts which are sold under the tradename Surlyn and Nucrel by Dow.

Ionomers are frequently used as tie-layer or adhesive resins which provide excellent adhesion to aluminum and other polar substrates. Other important applications include coatings, inks, surface films for golf balls, food packaging, sports equipment, skin and stretch films, and overmolded (cosmetic) bottles.