Diethylhexyl Phthalate (DEHP) is the most common member of the glass of phthalates, which are used as plasticizers. DEHP does not evaporate easily, and little will be present in the air even near sources of production. It dissolves more easily in materials such as gasoline, paint removers, and oils than it does in water. DEHP is present in plastic products such as wall coverings, tablecloths, floor tiles, furniture upholstery, shower curtains, garden hoses, etc.
Due to its suitable properties and low cost, DEHP is widely used as a plasticizer in manufacturing of articles made of PVC. Plastics may contain 1% - 40% of DEHP. DEHP is manufactured by the esterification of phthalic anhydride with 2-ethyl-hexanol:
C6H4(CO)2O + 2 C8H17OH → C6H4(CO2C8H17)2 + H2O
This reaction occurs in two successive steps, which are elevated temperature and a catalyst to accelerate the reaction rate. Depending on the catalyst used, the temperature in the second step varies from 140oC to 165oC with acid catalysts and from 200oC – 250oC with amphoteric catalysts. Excess alcohol is recovered and recycled and DEHP is purified by vacuum distillation and/or activated charcoal. The reaction sequences is performed in a closed system. This process can be run continuously or batchwise.
Mixing DEHP with polymers or other materials to compounds or masterbatches. This may take place at the processing site or at a separate size.
A large number of different technologies are used to process polymers with DEHP, for example calendering, extrusion, injection moulding and several plastisol applications including various moulding and coating technologies
- Industrial Use of Non-Polymers
The industrial use or professional use of sealants, adhesives, paints, lacquers, printing inks and ceramics.
The emission of DEHP from products in use, for example from roofing, PVC-coated fabric and car under-coating.
DEHP is the most common phthalate plasticizer in medical devices such as intravenous tubing and bags, IV catheters, nasogastric tubes, dialysis bags and tubing, blood bags and transfusion tubing, and air tubes.