Plasticiser Migration Study Ranks Phthalates And Alternatives by Effect on Non-PVC Plastics in Medical Devices

Teknor Apex, a US supplier of polymers with a specialism in elastomerics, has completed a study of plasticiser migration as it may affect non-PVC thermoplastics that are widely used for medical device components which come into contact with components made of PVC, it was announced today by the company’s vinyl division.

The study focuses on four materials commonly used in conjunction with PVC: ABS, acrylic, polycarbonate (PC), and polystyrene (PS). A typical example is that of PVC tubing used with PC connectors, but the study has implications for other PVC devices such as bags and masks. The results shows that in such applications, certain plasticisers may cause softening, cracking, or other defects in non-PVC components as they migrate across the interface with the component made of PVC, while other plasticisers exhibit little or no such effects. 

The study results are of special interest to manufacturers of PVC devices who are considering switching to compounds containing alternatives to the phthalate plasticisers, such as DEHP, that have been widely used in PVC medical devices, according to Peter M Galland, industry manager for medical compounds. He noted that while some non-phthalates exhibited deleterious effects on the non-PVC plastics studied, others were shown to be acceptable for contact with some or all of them (see accompanying table, in which plasticisers are ranked vertically by acceptability).

“Teknor Apex conducted this study to help manufacturers make informed decisions about prospective alternative PVC formulations, and indeed about the materials used in conjunction with PVC,” said Mr Galland. “We are prepared to supply each customer with exactly the right PVC compound, whether it incorporates a standard Plasticiser or any of the alternatives now available.”

The phthalate plasticisers in the study included DEHP and DINP, both of which were not recommended for contact with three of the four non-PVC materials; and DPHP, which was found acceptable for contact with three of them.

The non-phthalate plasticisers and recommendations based on the study include:

● Polymeric: usable for contact with all four non-PVC materials.

● TOTM, a trimellitate: usable for contact with all four non-PVC materials.

● DOTP, classed as a non-phthalate in spite of its chemical name of di-octyl terephthalate: usable for contact only with ABS.

● DINCH: usable for contact only with ABS.

● DOA, an adipate: not recommended for contact with any of the four non-PVC materials.

● Benzoate: not recommended for contact with any of the four non-PVC materials.

● ATBC, a citrate derived from citric acid: not recommended for contact with any of the four non-PVC materials.

Details on the study are posted at http://www2.teknorapex.com/PVC-Plasticizer-Migration.