1 Jun 2010
Polyscope Polymers expands scope of Xiran® SMA as additive for amorphous thermoplastics
“SMA additive increases value of ABS, PMMA by boosting thermal performance, paintability and compatibility in multi-material systems”
Styrene maleic anhydride, long established as a high performance thermoplastic in its own right, is now finding increasing use as a functional additive and compatibilizer in other amorphous and to some extent crystalline thermoplastics. Major SMA producer Polyscope is leading the way in expanding the use of this polymer as a property enhancer.
The company’s Xiran SMA additives can boost performance and value of various virgin and recycled resins, particularly ABS and polymethyl methacrylate (PMMA). They can improve thermal stability and widen the processing window, and make parts easier to bond, paint, print on, or plate at cost significantly below that of several other additives and proprietary polymer modification techniques. They also act as excellent compatibilizers between resins that are normally immiscible, such as PA/ABS.
Polyscope Polymers BV has its headquarters and production in Geleen, the Netherlands and has sales and marketing offices in Detroit and Shanghai. It currently has the industry’s broadest offering of SMA additives (as well as molding compounds). Grades vary in molecular weight and maleic anhydride content, both of which have important effects on host polymer properties.
SMA’s special properties derive from the combination of polar maleic anhydride (which also contributes stiffness, thermal stability, and chemical reactivity) and non-polar styrene (which also provides processing ease). This block copolymer is miscible in a wide range of plastics, which enables it to be used as a compatibilizer in multi-polymer systems.
Increase thermal performance and dimensional stability
Xiran SMA’s high glass-transition temperature (Tg) range of 145-175°C makes it a very cost-effective means of boosting high temperature performance in PMMA and ABS resins. Dimensional stability is also improved. The addition of between 1.5 and 3.3% SMA typically raises Vicat softening point by around 1°C. Compounders and recyclers can take lower value, standard- or scrap-grade ABS and transform it into value-added high-heat ABS using SMA resin, which is less costly and far more accessible than competitive technologies like N-phenyl maleimide (NPI) and alpha-methyl styrene acrylonitrile (AMSAN). In ABS, SMA can yield Vicat B values of 85-120°C.
Since SMA is fully miscible in PMMA and is also clear, it can improve acrylic’s thermal performance as well as resistance to stress cracking and exposure to chemicals like detergents – all while maintaining optical properties. For every 1°C increase in thermal performance desired in the base compound, as little as 1.8-2.3% SMA needs to be added.
Modify surface polarity and reactivity
Xiran SMA additives also increase the polarity of the base resin, making parts easier to paint, plate, print on, and bond to a wide variety of other materials. Processers can often skip the primer step in painting operations, saving both time and cost to produce finished parts. “Our technology is being driven by the search for higher quality and fewer defects,” says Patrick Muezers, managing director, Polyscope Polymers.
The additives also increase the compatibility of PMMA and ABS base resins with glass and natural fibres, rubber particles, thermoplastic elastomers and polymers such as polyamides with which they are normally immiscible.
Compounding and moulding with Xiran SMA additives
Grades of Xiran® SMA are available in granular form for either injection molding or extrusion. A liquid form factor is also available for fiber-coating treatments. Typical letdown rates range from 20-40 wt-% SMA, with a maximum of 60% used depending on the application requirements. Compounding can be done on most conventional equipment with good temperature control. SMA also is a very-effective purging compound due to its inherent polarity, so compounding or molding with it helps ensure clean equipment.
Typical automotive applications include instrument-panel (IP) carriers, air ducts, and other high-precision interior parts. Common non-automotive uses for SMA additives in ABS or PMMA resins include food packaging, chrome-plated sanitary parts, and components for building & construction, electrical and electronics, appliances/white goods, and lighting applications.
“SMA is such a versatile and cost-effective polymer modifier, that we see its use as an additive in acrylics and ABS as well as other thermoplastic systems increasing as customers learn of the many benefits it brings,” says Muezers. “It’s exciting to see a dynamic company like Polyscope fulfilling its slogan “Fresh Thinking, Great Products” by working closely together with partners within the engineering plastic market; developing not only complete new applications but also, with the use of its pilot plant, new neat resin types of SMA. Be assured that Polyscope Polymers is working to expand both our capacity and product offerings to meet our customers’ current and future needs for SMA additives.”
Prins de Lignestraat 28
6161 CZ Geleen
PO Box 1073
6160 BB GELEEN
+31 46 75 00 010
Notes for editors
About Polyscope Polymers
Polyscope Polymers BV is a Netherlands-based producer of styrene maleic anhydride copolymers, founded in 2006 by a group of international private investors backed by Limburg Development and Investment Company LIOF and Limburg Ventures. Polyscope offers a range of products with molecular weights from 10,000 up to 180,000 g/mol and a maleic anhydride content between 22% and 42%, for engineering plastics applications and also for water-based applications in paper, ink, pigment, leather treatment and other industries.