WEB EXCLUSIVES The bark of a high-yield variety of guayule plant is being used to produce a medical grade of natural rubber that is free of Hevea rubber proteins associated with allergies to latex from rubber trees.

WEB EXCLUSIVES The bark of a high-yield variety of guayule plant is being used to produce a medical grade of natural rubber that is free of Hevea rubber proteins associated with allergies to latex from rubber trees. Yulex Corp., Maricopa, Ariz., exhibited its new guayule latex for the first time at the MD&M show in Anaheim, Calif., last Feb. Yulex last year won FDA approval for use of its latex for medical examination gloves and is now working with balloon catheter manufacturers to get FDA approval for Yulex natural polymer catheters, as well as tracheal tube cuffs, surgical gloves, condoms and other products. Yulex has a 110,000-lb/yr pilot plant in Arizona and will double its capacity in six months. Yulex polymer emulsions come in two formulas: Yulex HA (ammonia base) and Yulex KOH (potassium hydroxide base), available as uncompounded base formula, pre-vulcanized, or custom compounded with colors, fragrances or special additives. Yulex has a density of 0.94 g/cc and exceptional strength and high elasticity, the company claims. Yulex base compounds when cured have a tensile strength of 27 to 31 MPa, elongation of 900 to 975%, and flexural modulus of 500%. Aged 7 days at 70 C, Yulex has tensile strength of 23 to 27 MPa, elongation of 675 to 750%, and flexural modulus of 3.6 to 4.2 MPa. Yulex plans to start a 3.3-million-lb/yr production plant by the end of this year for the liquid emulsion, which can be dipped, sprayed, cast, or foamed. (520) 381-2279 * www.yulex.com