Sabic Innovative Plastics (Pittsfield, MA) will expand its capacity and offerings for long glass fiber-filled polypropylene (LGFPP) resins through the acquisition of RheTech Inc.’s (Whitmore Lake, MI) RheMax product line and a toll-manufacturing agreement with the company for its line of Stamax LGFPP materials. Under terms of the deal, existing RheMax products will be integrated under the Stamax brand name, with product formulations maintained. Stamax was originally launched as a joint venture between DSM N.V. (Heerlen, Netherlands) and Owens Corning (Toledo, OH). Sabic acquired the line with its purchase of DSM Petrochemicals in 2002.

RheTech’s Dave Bening told PlasticsToday that Sabic’s purchase of its RheMax line includes all grades of materials in a matrix ranging from 20-40% fiberglass content, including homopolymer copolymer resins, as well as UV and non-UV stabilized grades with natural and black color options. Stamax will be available with glass loadings from 20, 30, and 40% in homopolymer and copolymer resins in North America, with concentrates up to 60% glass filled available from Sabic’s operations in Europe, according to Banu Kukner, Sabic Innovative Plastics’ marketing communications manager for global specialty film, sheet, and automotive.

Sabic launched Stamax in North America in September 2008, and it says this new deal with RheTech will give it localized production of the materials, which specifically target the automotive industry. According to Sabic, Stamax LGFPP resins have 10-25% lower density than competitive materials, better surface finish than short-glass-fiber products, and allow molded-in-color. Stamax combines a (PP) base resin with long glass fibers and has found application in front-end modules (FEM), door modules, instrument panels, center consoles, underbody shields, seating systems, liftgates, and tailgates. Stamax LGFPP is used today in the  Mercedes-Benz M-Class instrument panel.

Kukner told PlasticsToday that its Stamax LGFPP pellets are typically supplied at a length of 12 mm. Although injection molding can have a significant effect on final fiber-length distribution, Kukner says parts can be molded from granulate long-fiber pellets with mean fiber lengths between 2 and 4 mm.

Bening said RheMax and Stamax are not produced via pultrusion, but rather both use what’s known as a “wirecoating” process licensed from Owens Corning by RheTech and Sabic. “All RheMax and Stamax grades have been made by same process, have same/similar recipes, and share product nomenclature aside from tradename,” Bening said, “therefore the transition for RheMax to become Stamax in this business transfer to Sabic in North America is a tradename change.”

RheTech makes automotive OEM specified PP compounds, including blowmolding and extrusion grades, as well as ones reinforced with short-glass fibers, mica, talc, and calcium carbonate, among other fillers. Through its LNP custom-compound business Sabic markets another line of highly filled composites. The Verton line contains 25-70% long-glass-fiber content by weight and is made via a patented pultrusion process it says maintains fiber length and alignment. The technology uses a range of base resins, with the most commonly specified ones being polyamide (PA) and polypropylene (PP).

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