Irradiated polyethylene resins go into production

A Sterigenics International, Advanced Applications product story

Edited by the Engineeringtalk editorial team Dec 1, 2004

With four different resin grades, the Raprex line of irradiated polyethylene (PE) resins has now moved from testing into production.

"Customer response and demand for Raprex irradiated polyethylene (PE) resins has exceeded market expectations and proven to be a valuable addition to the plastics industry", Lewis Parks, PhD, Vice President, Sterigenics Advanced Applications, announced recently.

With four different resin grades (introduced on a test basis in mid 2003), the Raprex line has now moved from testing into production.

In order to meet current and future product demand for both the processing of PE resins and the production of Raprex, Sterigenics has also announced a major expansion of its Gaithersburg, MD facility.

This expansion will include specialised handling equipment to process material in the most efficient and uniform manner.

It will also include the addition of hoppers and silos designed to handle truckload quantities of materials.

"We are pleased with the market interest and response to the performance of our Raprex line of irradiated polyethylene resins", said George Forczek, Product Manager for Raprex Products.

"We*ve received numerous inquiries regarding the Raprex resin line and processing and have received very favorable feedback from customers about the improvements compared to the base polymers".

"This expansion will enable us to satisfy the growing demand and to provide even more products to meet specialised customer requirements".

The equipment at the Gaithersburg facility will initially be dedicated to the processing of resin used in the Raprex process.

As the marketplace grows and new materials are developed, the plant will be able to adapt to market demands and continue the evolution of additional thermoplastic materials.

Long-chain branching, controlled crosslinking and controlled oxidation of polyethylene is achieved through the Raprex proprietary process established by Sterigenics with patent pending.

These modifications to the base resins result in the improvement of certain mechanical properties and allow the resins to be used in more demanding applications.

Sterigenics initially introduced four standard grades of Raprex: Raprex 100, introduced as the standard PE grade for extrusion and pipe applications; Raprex 200, for standard injection molding grade; Raprex 300, for blown film; and Raprex 400, for coating of steel, copper and other ethylene based resins.

"Since their introduction, we*ve been asked to provide modified versions for specific customer requirements, and have learned a great deal about the performance of these resins", said Forczek.

Unlike the irradiation of finished parts, or the addition of chemical cross-linking additives, the Raprex process allows the PE to be fully recyclable due to the control of the irradiation process.

The process will allow for lower waste and cost savings while being more environmentally friendly.