Volume 4 - Loctite.ph

IonomerThermoplasticTrade Names• Formion• SurlynManufacturerA. SchulmanDuPontTypical Properties of IonomerAmerican EngineeringSIProcessing Temperature 450°F to 500°F 232°C to 260°CGeneral DescriptionIonomers are copolymers of ethylene and meth(acrylic) acid whosephysical structure is distinguished by interchain ionic bonding. Thisbonding takes place between metal cations, such as zinc, sodium, andlithium, and an anion, such as the carboxylate group. Due to thedissociation of the interchain ionic bonding at high temperatures,ionomers can be processed using standard thermoplastic methods.Fillers are not typically used with ionomers, however glass fiber filledgrades are available. In 2004 dollars, the price of ionomers rangedapproximately from $1.27 to $2.25 per pound at truckload quantities.General PropertiesProperties of the ionomer resins vary with the amount and type ofmetal cation and the proportion of comonomer. Ionomers containingthe zinc cation have better flow, impact strength, tear strength, paintadhesion and lower moisture absorption. Those containing the sodiumcation offer lower haze and improved stress crack resistance, whilethe addition of the lithium cation increases the modulus. The goodthermal stability, outstanding chemical resistance, and low moisturevapor transmission of ionomers result from their polyolefin-likestructure. However, the interchain ionic crosslinking contributesexcellent abrasion, puncture, and impact resistance, as well as lowtemperature toughness. Moreover, most ionomers have good opticalclarity, and the less crystalline grades have superior clarity. Mostcommercial grades of ionomers comply with FDA regulations for foodcontact and food packaging which leads to their widespread use inthis industry as a film. Ionomers weather poorly, consequently UVabsorbers and stabilizers must be used in applications requiringresistance to weathering. Solvent resistance varies with the level ofmetal cation, but most ionomers are insoluble in common organicsolvents at room temperature and resistant to mild acids and bases.Linear Mold Shrinkage 0.003 to 0.006 in./in. 0.003 to 0.006 cm/cmMelting Point 175°F to 205°F 79°C to 96°CDensity 58.7 to 62.4 lb./ft. 3 .94 to 1.00 g/cm 3Tensile Strength, Yield 1.3 to 5.8 lb./in. 2 x 10 3 0.9 to 4.1 kg/cm 2 x 10 2Tensile Strength, Break 2.4 to 5.1 lb./in. 2 x 10 3 1.7 to 3.6 kg/cm 2 x 10 2Elongation, Break 150 to 520% 150 to 520%Tensile Modulus 0.1 to 0.5 lb./in. 2 x 10 5 0.1 to 0.4 kg/cm 2 x 10 4Flexural Strength, Yield – –Flexural Modulus 0.1 to 2.5 lb./in. 2 x 10 5 0.1 to 1.8 kg/cm 2 x 10 4Compressive Strength – –Izod Notched, R.T. 7.0 to No Break ft.-lb./in. 38.7 to No Break kg cm/cmHardness R50 - R68 Rockwell R50 - R68 RockwellThermal Conductivity 1.6 to 2.1 BTU-in./hr.-ft. 2 -°F 0.23 to 0.30 W/m-°KLinear ThermalExpansionDeflection Temperature@ 264 psiDeflection Temperature@ 66 psiContinuousService Temperature6.1 to 13.0 in./in.-°F x 10 -5 11.0 to 23.4 cm/cm-°C x10 -585°F to 115°F 29°C to 46°C100°F to 180°F 38°C to 82°C93°F to 118°F 34°C to 48°CDielectric Strength 400 to 450 V/10 -3 in. 1.6 to 1.8 V/mm x 10 4Dielectric Constant@ 1 MHzDissipation Factor@ 1 MHzWater Absorption,24 hr.– –0.002 to 0.003 0.002 to 0.0030.01% 0.01%Typical Applications• Packaging – Vacuum packaging of meat, tear-open packagesfor food and pharmaceutical products, heavy gauge film forelectronic products• Sporting goods – Golf balls, bowling pins, ice skates,ski boots, wrestling mats• Automotive parts – Bumper guards, exterior trim• Miscellaneous – Foam to make buoys, thin filmsfor bulletproof glass30The Loctite ® Design Guide for Bonding Plastics, Volume 4