additives feature | Plasticizers
The choice of PVC plasticizers continues to grow with the arrival of bio-based grades
of innovative plasticizers are related to the excellent plasticizing effectiveness and low cost of DEHP,” says Antonio Greco, assistant professor at the University of Salento in Italy. He says that an innovative plasticizer, called Placard, has been developed at the laboratories of the Department of Innovation Engineering at the university.
Placard is obtained by chemical modifica- tion of cardanol, an industrial grade yellow oil obtained from certain types of cashew nut shells. Cardanol is a by-product of the cashew nut industry, and its worldwide availability is estimated to be about 300,000 tonnes/year. Placard is obtained through esterification of the hydroxyl
group and epoxidation of the side chain double bond of cardanol. Greco says it yields
mechanical properties in PVC compa- rable to those of PVC plasticized by DEHP.
EASME, the European Commission’s Executive
Agency for Small and Medium-sized Enterprises, has funded the technological transfer of Placard processes to the industrial production scale, and subsequently the production of soft PVC for gaskets to be used in civil construction applications. The partners involved with Salento University in the
Placard project are: Serichim, which is in charge of the optimization of the chemical modification processes; gasket producer Kommi; and the EuPC, the European plastics converters association, which is in charge of
the commercial exploitation of the concept. Greco says that information from the ECHA database
indicates that the toxicological impact of cashew nut shell liquid (CNSL) is at the same level of concern as that of epoxidized soybean oil (ESBO). He points out that Placard is sourced from feedstocks that would not otherwise be destined for the food chain. “The full biodegradability of CNSL significantly reduces the environmental impact of soft PVC,” he further claims. “In addition, the excellent thermal stability of Placard is expected to favourably affect the mechanical recycling of soft PVC.”
Amorphous polyhydroxyalkanoate (PHA) copolymer
technology from Metabolix serves as a platform for another new range of bio-based plasticizers (as well as other polymeric performance modifiers and additives). Metabolix says: “Offering low glass transition tempera- tures (Tg) and exceptional miscibility in PVC, these new modifiers are easy to blend and disperse into PVC, bringing physical property enhancement and processing benefits during compounding such as reduced torque and processing temperatures.” The company claims that LMW liquid plasticizers, including ESBO, that are commonly used as bio-based alternatives to phthalates, are not very compatible with PVC and tend to migrate out over time. “Metabolix’s highly miscible, high MW PHA modifiers function as a compatibilizer to reduce migration (and extraction or volatilization) of primary and secondary plasticizers, such as phthalates and ESBO,” the company claims It adds that another drawback with using LMW
plasticizers is that they reduce toughness as they improve ductility. Amorphous PHA polymeric modifiers
Secondary plasticizers can reduce carbon footprint, cut costs, and improve fire resistance
At the PVC 2014 conference in the UK, two speakers from Ineos ChlorVinyls gave a paper with a rather provocative title: “MCCP – an update and ecoprofile for the world’s most popular plasticizer.” Medium-chain chlorinated paraffins
are widely used as secondary plasticiz- ers, and as Roger Mottram, group environmental and regulatory affairs manager, and product stewardship manager Chris Howick, pointed out, MCCPs (which the company markets under the Cereclor banner) can reduce material costs by 2-5% when used at
58 COMPOUNDING WORLD | August 2014
levels of up to 10% in very flexible compounds. Unlike primary plasticizers, MCCPs
contain chlorine so they also help retain PVC’s excellent flame retardant proper- ties. Furthermore, they can also help compounders cut their carbon footprints. MCCPs were fully registered under REACH in 2010. Ineos has collaborated with the
University of Manchester in England on life cycle analyses for the most popular MCCPs – various types are available, largely differentiated by levels of
chlorination. Tests demonstrated that, throughout their lives, MCCPs are the source of around 0.8 kg of CO2
equivalent
per kg of product, compared with 1.9 kg for suspension PVC, 2.5 kg for emulsion PVC, and 2.2 kg for DINP. The production process for MCCPs also yields food-grade hydrogen chloride, HCl (which has a useful life of its own), so the carbon footprint for MCCP can be considered either with or without the carbon footprint for HCL produced at the same time. ❙
www.ineos.com
www.compoundingworld.com
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