Materials (January 01, 2004)

Adhesive films by coextrusion

Bayer has developed a family of ethylene vinyl acetate copolymers which can be used in the production of transparent adhesive films by coextrusion. “Levamelt grades can be quickly and easily combined with other polymer granules of similar viscosity directly at the extruder,” explains Martin Hoch, an adhesives expert with Bayer Polymers. “The good cohesion of this material makes it possible to produce adhesive films by the coextrusion process.”

Bayer 800-668-2554

Improved flow length for SBC grades

Two injection molding grades of K-Resin styrene-butadiene copolymer (SBC) have been found to improve injection molding flow length up to 20% compared with like materials at the same temperature and pressure.

K-Resin BK10 and BK15 have a melt flow rate of 15 g/10 min, which permits molding with a higher length-to-thickness ratio, especially useful for long, thin parts.

Both resins provide parts with glass-like clarity, good toughness and stiffness, plus high surface gloss.

Chevron Phillips Chemical Co. 905-478-1213

Steam-sterilizable blister packaging from COC

Ticona has developed cyclo-olefin copolymer (COC) blends that allow blister packaging made form Topas COC films to be steam sterilized. These blends enable Topas COC-based film to be used as a barrier material for sterile products, such as liquid medications, solutions and veterinary pills.

The new family of formulations combines Topas 6013 COC and a polyolefin to create heat-resistant films that do not distort when heated to 121 C for 20 min.

“These films have almost no shrinkage or warpage in thermoforming, and provide an even wall thickess throughout,” explains Ekkehard Beer, key account director with Ticona. “The blisters made are either translucent or white, and have good surface smoothness and gloss.”

Ticona 908-522-7500

Syndiotactic PP is softer, clearer

Atofina’s Finaplas syndiotactic polypropylene products are softer than conventional isotactic PP, and provide better formability on containers. “Our customers continue to design films that incorporate Finaplas to replace paper and other converted film options, especially on difficult container designs,” says Scott McEwen, vice-president for polypropylene, Atofina Petrochemicals.

“This allows consumer product companies to design more uniquely shaped containers.”

The Finaplas resins exhibit exceptional clarity and gloss, a melting point of 128 C, and a low level of extractables. They also expand the range of film shrinkage and provide better clarity in cast and oriented films.

Other applications include: medical sterilizable applications, extruded foams, and injection molded consumer durables.

Atofina Canada Inc. 905-827-9841