Here Dr. Paul Goodman, Senior Materials Consultant at edifera provides an insight into the uses of the four phthalates restricted from 2019 / 2021.

 

Uses of four RoHS restricted phthalates

 

The RoHS directive will ban four phthalates in electrical equipment from 22 July 2019 (2021 for categories 8 and 9). The table below summarises their main uses.

Substance

Main uses in electrical and electronic equipment

Bis-ethylhexyl phthalate (DEHP)

Plasticiser used in PVC, rubber and in other polymers. A main use was in cable and wire insulation, but this has declined to DEHP being a REACH SVHC.

Also used in PVC tubing (including for medical applications), medical blood bags, in sealants and adhesives. As a dielectric in large high voltage capacitors and in hydraulic fluids.

Added to a wide variety of rigid polymers as a processing aid.

Dibutyl phthalate (DBP)

Plasticiser in plastics including nitrocellulose and polyacetate, but is not used in PVC, except as a co-plasticiser. Used in flexible varnishes, nitrocellulose paints and film, "sizing" glass fibre before impregnation & in paper coatings. Added as a flexibilizer in rubbers and in paints.

Di-isobutyl phthalate (DiBP)

This is being restricted as it is a potential substitute for DBP due to its very similar properties. A recent study by the Oeko Institut however, found no uses in electrical equipment, although it has been used in lacquers.

Benzyl butyl phthalate (BBP)

Plasticiser for PVC foam used for floor tiles and imitation leather, etc., but is uncommon in wire and cable (as a co-plasticiser). An additive in flexible adhesives, potting materials, lacquers, sealants, paints, coatings and inks. Also used in polyurethane adhesives, in polyurethane rubbers and in polysulfide and acrylic-based polymers.

 

Although there are many alternative plasticisers, drop-in replacement is not usually possible and so reformulation of the plastic material will be required. All have advantages and disadvantages and for each application, there may be only a very few options. Many of the newer phthalate-free plasticisers have not been comprehensively tested for health and environmental hazards so these are not always known. Some of the phthalate-free alternatives have recently come under scrutiny because hazard properties have been discovered.