additives | PVC plasticisers
segments such as resilient flooring and vinyl leather- cloth – are not always easy to achieve. “Terephthalates have not been widely used until recently due to their poor compatibility with PVC, resulting in a performance gap when they are used in place of orthophthalates,” she claims. “Problems encountered by formulators include
Above: Developing alternative plasticisers that offer equivalent performance in applications such as synthetic leather is not easy
announcements geared toward phthalate deselection; Wal-Mart’s new policy calls for manufacturers to list DEP (diethyl phthalate) and DBP (dibutyl phthalate) on packaging and to work to find alternatives, while Target announced a $5m investment in green chemistry innovation.
Back to the floor “One interesting trend we’ve seen with the evolution of the PVC market away from phthalates is that it seems to be driven by relatively small segments within the larger flexible vinyl market,” says Emerald R&D Applications Manager Emily McBride. “For example, vinyl flooring makes up roughly 5% of the market, but due to its close consumer contact, high visibility, and impact on indoor air quality, it has been examined more critically. Changes made by vinyl flooring manufactur- ers to satisfy consumers and NGOs have then been pulled through the rest of the much larger flexible vinyl market on a global level, and especially in the US and Western Europe.” Plasticiser use in vinyl flooring came under the spotlight at the Polymers in Flooring conference organised by Compounding World publisher AMI in Berlin, Germany, last December, with ExxonMobil presenting a strong justification for use of its Jayflex DINP (diisononyl phthalate) high molecular weight plasticiser in flooring plastisols. The company’s Global Plasticisers Advisor Didier Naert explained that, with a boiling point of more than 400˚C, DINP does not contribute to VOC or SVOC emissions. He also present- ed data showing that DINP offered benefits including faster processing and improved foam structure. Emerald’s McBride says the replacement of
phthalates with alternatives has presented considerable challenges for formulators. She points out that equivalent performance in terms of staining and extraction resistance – essential characteristics in
42 COMPOUNDING WORLD | August 2017
plasticiser exudation, increased processing energy requirements, and poor processability. Recently, we have worked with many formulators that, rather than implementing one type of chemistry as a solution, turn to plasticiser blends as alternatives,” McBride says. “High solvating plasticisers such as dibenzoates have very good compatibility with PVC, resulting in excellent processing and performance characteristics. We see them increasingly employed as part of a blend, where they can compatibilise less compatible plasticisers such as DOTP [dioctyl phthalate] to close the performance gap and yield an excellent balance of characteristics.” McBride also highlights the health and safety
profiles of dibenzoates. “Many do not require any warning levels including two widely used, DEGDB [diethylene glycol dibenzoate] and DPGDB [dipropylene glycol dibenzoate], and some also have FDA approvals for direct food contact,” she says.
Polymeric options COIM says it has developed many new polymeric plasticisers as alternatives to phthalates in recent years, including its Plaxter P and Plaxter PL products. Marketing Manager Paola Bocchese says the use of Plaxter P, in combination with monomeric plasticisers, has been increasing “due to technical and legal requirements”. She points out it would be near impos- sible to produce flexible PVC products for applications in contact with hydrocarbons, oils, fats, soaps and other agents that can extract the plasticiser without the use of polymerics as an alternative to popular monomerics such as DINP, DINCH (1,2-cyclohexane dicarboxylic acid diisononyl ester) and DEHT (dioctyl terephthalate). “Without the use of Plaxter P, as an alternative to
standard monomeric plasticisers, it is practically impossible to comply with the current EU or US FDA regulations which require not only the use of additives coming from a specific positive list, but also a strong reduction of the specific and global migration limit (SML/GML),” Bocchese says. The recently developed Plaxter PL grades are “a good
first step into bio-plasticisers and have a reasonable and acceptable price level,” Bocchese claims. The PL grades contain 15-35% of raw materials from renewable sources derived from waste and are said to achieve the same good results as Plaxter P. “Now that the raw materials
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PHOTO: SHUTTERSTOCK
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