TECHNOLOGY | POLYMER FOAM
negative effect on physical properties,” Schroeck says. “Azodicarbonamide (ADC) chemical foaming agents are being de-emphasised in most markets that deal with food or children’s products due to toxicity concerns, as well as REACH. Carbonate- based chemical foaming agents are usually food, medical and toy approved. They are an acceptable substitute in most rigid applications but there are limitations in elastomeric products. For compound- ers, carbonate foams can be more difficult to com- pound due to shear- sensitivity.” Reedy Chemical
Foam has devel- oped its Safoam P and Safoam HT chemical foaming agent
Above: Foamed trays produced using SABIC’s latest ultra- high melt strength PP
Right: Foamed PS profile produced using Safoam RAZ-70
powders for easier compounding and to more closely match the gas decomposition points and process points of ADC foaming agents. The company says that the new chemical foaming agent powders create carbon dioxide in-situ, which results in a finer cellular structure in the finished part. Safoam P powder and Safoam RAZ-70 pellets are a hybrid of carbonate and ADC foaming agents. The combina- tion is said to provide the robust gas release of ADC with the cooling gas created by the carbonate foaming agent. A recent project Reedy Chemical Foam has been involved with involved polystyrene extruded with the Safoam RAZ-70 hybrid blowing agent. No physical gas is used in this application - the density reduction and cell quality created only by the chemical foaming agent. Markets for this type of foamed polystyrene extrusion include picture and mirror frames and point-of-purchase displays. The cellular structure was created using Safoam RAZ-70, dosed at 0.35% with the polystyrene resin. Properties are shown in Table 1. Future developments Reedy Chemical Foam is looking to address with its blowing agents include improving the melt strength of PET and bio-poly- mers, such as PLA and PHA, that will allow for improved density reductions and easier processing. SABIC has added an ultra-melt strength polypro-
pylene resin to its foam range for a wide variety of industrial applications. The company says that SABIC PP-UMS has a melt strength of more than 65cN and good foamability. It can be used by all industry segments as a building block to develop new foaming solutions that enable lightweighting. “Looking to the future of lightweighting, we see
that foaming is a key technology to push the boundaries and create even more down gauging
60 COMPOUNDING WORLD | January 2018
www.compoundingworld.com
Table 1: Properties of polystyrene dosed with 0.35% Safoam RAZ-70
Non-foamed density Foamed density Density reduction Average cell size
Source: Reedy Chemical Foam
opportunities in the industry. For this reason, our global teams are busy developing the next generation of foamable resin solutions for the market. These solutions can be used in many processing technologies to best meet the unmet needs of the value chain,” says Frank de Vries, SABIC’s Global Foam and Lightweight Leader. According to the company, the new SABIC
PP-UMS material can be used to enhance light- weighting in the automotive, packaging and building and construction markets. The resin was evaluated and optimised for foaming at SABIC’s Foam Innova- tion Centre (FIC) in The Netherlands, which is equipped with wide variety of foaming production technologies as well as analytical equipment.
Consistent production Sustainability is identified as a strategic issue for Clariant and lightweighting of plastic articles is one of the areas that it believes it can contribute to that with its Hydrocerol range of chemical foaming agents. “Major trends in polymer foaming technol- ogy include dosing accuracy, good dispersion, as well as fast and complete decomposition of chemical foaming agent masterbatches for consistent production,” says Micro Groeseling, Global New Business Development Manager. “The finest cell structures combined with high mechanical properties of the end-use plastic articles is a must,” he says. “Our newest generation of Hydrocerol endothermic chemical foaming
1.035 0.608 48%
114 microns
PHOTO: SABIC
PHOTO: REEDY CHEMICAL FOAM
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