Silicone-based TPEs go commercial. (Materials).

The world's first family of TPEs based on vulcanized silicone rubber particles in a thermoplastic matrix was introduced commercially in September. (See PT, June `02, p. 41 for an initial report.) Called TPSiV (thermoplastic silicone vulcanizate), they were developed by Dow Corning Corp. but are now being produced and sold by Multibase in Copley, Ohio, which Dow Corning purchased in May.

TPSiv extends the range of TPE and TPV performance by offering high heat resistance, low tensile and compression set at elevated temperatures, and excellent resistance to abrasion, hydrolysis, and chemicals, including fuel and oil. TPSiV comes in black, "appliance white," and colors. It is printable and paintable. It has a non-tacky feel and lends itself to coextrusion and overmolding because it bonds without adhesives to polycarbonate, ABS, nylon 6, TPU, and PVC. List prices are $4.55 to $5.90/lb.

The first four grades are based on two different thermoplastic matrixes. One grade, TPSiV 1180-50D, has 52 Shore D hardness and is essentially a flexible nylon (the matrix resin). It boasts good melt strength and drawdown properties, suiting it to profile and tubing extrusion. Continuous-use temperature (by SAE test) is 140 C (284 F).

The TPSiV 3000 series for injection molding and extrusion is more rubbery and elastic. These grades contain a proprietary matrix resin. They have an unusual dry, silky touch and a use-temperature range from 150 C (302 F) down to -50 C (-58 F). They withstand more than 1000 hr aging at 150 C in air or in boiling water. The 3010 grades (52A and 65A) have lower compression and tensile set, while a 3011 grade (65A) has higher tensile and tear strengths and a silkier feel. It is also blow moldable. TPSiV 3010-50A, the only grade containing a plasticizer, is said to be the first 52A TPE that retains its tensile properties in continuous use at 150 C. Tel: [phone], www.multibase.com