Exxon Chemical Co. last week disclosed two major breakthroughs in its development of Exxpol polyolefin technology.
It listed the breakthroughs as:
- Gas phase manufacture of metallocene linear low density polyethylene (Mlldpe) at a recently retrofitted world-scale plant.
- Development of supercondensed mode polymerization with metallocene catalysts for which the company received a U.S. patent Apr. 11.
The world-scale Mlldpe plant is in Exxon Chemical's Mont Belvieu, Tex., complex. Using its proprietary Exxpol catalysts, manufactured by Exxon at the complex, the initial line ultimately will be able to produce I billion lb/year of Mlldpe. The products will be used at first to make advanced blown and cast films for high-strength plastic packaging such as industrial strength film, can liners, and shipping sacks.
The patent is the latest in a series of gas phase polyolefin polymerization process patents the company owns or expects to be issued. It extends Exxon's patent coverage to specifically include polyolefin production with metallocene catalysts in condensed and supercondensed modes.
Exxon plans eventually to use this technology at all its gas-phase polyethylene plants around the world. In addition, the company plans to license its Exxpol and supercondensed mode technologies to gas phase polymer producers throughout the world.
STRONG MARRIAGE
"The true strength of our supercondensed mode invention is its marriage with our Exxpol metallocene catalysts," said Douglas M. Selman, vice-president of Exxon polymers technology. "We've been very pleased with our pilot plant and world-scale plant trials using this innovative Exxpol technology."
Supercondensed mode operation allows a producer to significantly expand the capacity of existing gas-phase reactors with considerably lower investment costs than necessary for construction. Coupled with metallocene catalysts, the results are even more valuable to producers and customers and intriguing to licensees, Exxon said.
It also said Exxpol-Lldpe technology can produce Mlldpes incorporating higher alpha olefin comonomers, such as hexene, which can be reduced at rates equal to today's conventional ethylene-butene copolymers, providing higher-performing resins for typical applications.
Exxon Chemical has been conducting world scale plant trials and evaluating the new products in the marketplace since 1993. It plans to introduce Mlldpes broadly to customers in second half 1995.
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