New Approach in EPDM Sponge Profiles with Metallocene Elastomers

EPDM is one of the most widely used synthetic rubber in exterior sealing system, in particular in automotive sponge weatherstrips  insuring excellent water, dirt and noise insulation over the life time of the car. It is related to its unique properties of air and ozone resistance combined with its compounding versatility to produce performing profile at relatively low cost.

 Advances in metallocene polymerization technology over the past decade provide the ability to design high performance elastomers with tailored properties through a precise control over the molecular architecture and comonomer introduction. 

 In this paper, we will present different approaches in formulating EPDM sponge compounds with blends of elastomers such as amorphous and high diene EPDM rubber, amorphous and high molecular weight EPDM or propylene – ethylene elastomer copolymer.

 We will describe the elastomer properties, formulation optimization studies and the properties of sponge profiles produced in a semi-industrial UHF extrusion line.

 We will demonstrate that it is possible reducing the density of a sponge profile whilst controlling its key attributes, such as compression load deflection and compression set, to meet the stringent automotive specifications.