Volume 4 - Loctite.ph

Polypropylene (PP)ThermoplasticTrade Names• Adpro• Astryn• Azdel• Endura• Fortilene• HiGlass• Marlex• Moplen• Nortuff• Petrothene• Polyfort FPP• Rexene PP• Tonen• Unipol PP• ValtecManufacturerGenesis PolymersHimont USA, Inc.Azdel, Inc.PPG Industries, Inc.Solvay PolymersHimont USA, Inc.Phillips 66 CompanyHimont USA, Inc.Quantum ChemicalQuantum ChemicalA. Schulman, Inc.RexeneTonen PetrochemShell Chemical CompanyHimont USA, Inc.General DescriptionPP is manufactured by the polymerization of gaseous PP monomer, inthe presence of an organometallic catalyst, at low pressure. The key toPP’s properties is its crystallinity, which is determined by the degreeof organization of the methyl groups on the polymer’s backbone.Syndiotactic PP is formed when the methyl groups alternate aboveand below the plane of the main polymer chain. On the other hand,isotactic PP is formed when the methyl groups all lie above (or below)the plane. Finally, atactic PP results when the methyl groups arerandomly positioned. Specialty grades available include calciumcarbonate, carbon, copper, glass, mica, mineral, and glass bead filled.In 2004, the price of PP ranged approximately from $0.70 to $10.50per pound at truckload quantities.General PropertiesPP is known for its good mechanical properties, heat resistance, andchemical resistance. In addition, PP has the highest flexural modulus ofthe polyolefins, is among the lightest of the engineering thermoplastics(SG=0.90), and has excellent moisture resistance. One of the majordisadvantages of PP is its poor impact strength at low temperatures.However, PP/elastomer blends are available with much improved impactresistance. PP’s mechanical properties are very dependent on its degreeof crystallinity. Isotactic PP is harder, stiffer, and has a higher tensilestrength than atactic PP, while atactic PP exhibits better impact strengthand elongation under stress. Random copolymers are produced byintroducing small amounts of ethylene into the polymerization reactorand result in much improved clarity and toughness at the expense ofstiffness. PP is chemically resistant to most substances includingnonoxidizing inorganics, detergents, low-boiling hydrocarbons, andalcohols. Unfilled PP is flammable and degraded by UV light; however,flame retardant and UV stabilized grades are available.Typical Properties of Polypropylene (PP)American EngineeringProcessing Temperature 390°F to 460°F 199°C to 238°CLinear Mold Shrinkage 0.011 to 0.020 in./in. 0.011 to 0.020 cm/cmMelting Point 320°F to 360°F 160°C to 182°CDensity 56.2 to 56.8 lb./ft. 3 0.90 to 0.91 g/cm 3Tensile Strength, Yield 2.8 to 5.4 lb./in. 2 x 10 3 2.0 to 3.8 kg/cm 2 x 10 2Tensile Strength, Break 2.5 to 5.4 lb./in. 2 x 10 3 1.8 to 3.8 kg/cm 2 x 10 2Elongation, Break 1.8 to 500% 1.8 to 500%Tensile Modulus 1.4 to 2.1 lb./in. 2 x 10 5 1.0 to 1.5 kg/cm 2 x 10 4Flexural Strength, Yield 3.7 to 7.5 lb./in. 2 x 10 3 2.6 to 5.3 kg/cm 2 x 10 2Flexural Modulus 1.1 to 2.5 lb./in. 2 x 10 5 0.8 to 1.8 kg/cm 2 x 10 4Compressive Strength 3.5 to 4.7 lb./in. 2 x 10 3 2.5 to 3.3 kg/cm 2 x 10 2Izod Notched, R.T. 0.3 to 1.0 ft.-lb./in. 1.6 to 5.4 kg cm/cmHardness R65 - R105 Rockwell R65 - R105 RockwellThermal Conductivity 0.8 to 1.6 BTU-in./hr.-ft. 2 -°F 0.12 to 0.23 W/m-°KLinear ThermalExpansionDeflection Temperature@ 264 psiDeflection Temperature@ 66 psiContinuousService Temperature2.1 to 6.5 in./in.-°F x 10 -5 3.8 to 11.7 cm/cm-°C x10 -5SI140°F to 300°F 60°C to 149°C225°F to 310°F 107°C to 154°C200°F to 250°F 90°C to 121°CDielectric Strength 580 to 990 V/10 -3 in. 2.3 to 3.9 V/mm x 10 4Dielectric Constant@ 1 MHzDissipation Factor@ 1 MHzWater Absorption,24 hr.2.1 to 2.7 2.1 to 2.70.0002 to 0.0005 0.0002 to 0.00050.01 to 0.03% 0.01 to 0.03%Typical Applications• Fibers – Carpet backing, diaper coverstock, rope• Packaging – Packaging films, bottles, prescription vials• Appliance – Washer agitators, dishwasher components• Miscellaneous – Straws, luggage, syringes, toys,storage battery cases62The Loctite ® Design Guide for Bonding Plastics, Volume 4