ExxonMobil’s Santoprene™ Thermoplastic Vulcanizate TPV, when extruded into sheet, is used in the speaker (car and home) industry. Extruded Santoprene™ sheet products are then vacuum formed into speaker surrounds and attached to the cone. Manufacturers use materials like Santoprene™ TPV speaker surrounds due to several added benefits including weather resistance, flex fatigue capabilities, and multiple grades/durometers.
Santoprene™ performs well in almost all weather conditions, therefore making it weather resistant. Before Santoprene™ surrounds, speaker surrounds were to be kept dry because foam surrounds tend to rot with moisture. This TPV from ExxonMobil™ can withstand pretty much any environment you put it through. Santoprene™ has the environmental resistance that is comparable on almost all standards to EPDM rubber compounds. Polypropylene, a main component of Santoprene™, has a surface energy of 29 dynes/cm2 versus water 72 dynes/cm2. The large difference between the 2 dyne measurements causes the Santoprene™ to repel water at a high level.
Its flex fatigue resistance is unmatched, which makes it extremely durable after years of use. Speaker surrounds are made of Santoprene™ because they provide low distortion and high efficiency mid-bass performance. Santoprene™ is comparable to a foam surround, but has a lifespan that can outlast foam. The function of a speaker is to create vibration through fluctuating electric current, which puts stress on the speaker surround. Speaker manufacturers use Santoprene™ because of its ability to handle stress throughout the lifetime of the speaker.
Just like any chemical compound, Santoprene™ TPV can be delivered at multiple durometers that range from a hardness of 35 Shore A up to 50 Shore D. Santoprene’s™ sound lifespan and weather resistance is why it is widely respected in the car and home speaker industry. When determining what durometer to use when making a speaker surround, contact a sales rep at Sherwood Industries, Inc.
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