Plasticizer - Di(2-Propyl Heptyl) Phthalate

Di(2-propylheptyl) phthalate (DPHP) is a colorless liquid plasticizer used to make PVC and PVC copolymers flexible. It is a member of the nonphthalate family of plasticizers that are not based on phthalic acid.

It meets modern safety regulations and replaces classified chemicals such as DOP. It is also less toxic to the environment than DOP.

Properties

Di(2-ethylhexyl) phthalate (DEHP) is a clear, colorless and odorless liquid plasticizer. It is soluble in most organic solvents and miscible with PVC. DEHP provides good gelling, electrical properties and tensile strength. It also offers good resistance to cold temperatures and high-temperature flexibility.

The low molecular weight phthalate DEHP has been used as a general purpose plasticizer, but due to strict regulation it has progressively been replaced by DINP and other higher molecular weight phthalates. In our samples from house dust and SPM this has resulted in a shift of the total concentration of plasticizers towards these higher molecular weight phthalates.

These plasticizers are primarily used in medical PVC applications like blood bags and tubing, flexible IV tubes, catheters, protective gloves and surgical drapes. However, they can also be found in toys and other applications requiring high-temperature flexibility. Due to their chemical structure, these higher molecular weight phthalates are less suitable for use in applications that require low-temperature flexibility.

Applications

DPHP is used to improve the softness and flexibility of polyvinyl chloride (PVC) products by creating large inter-molecular spaces between polymer chains. It also imparts flame retardant properties to PVC materials. It is available in general, electrical, and food grade varieties. The general and electrical grades of DPHP are used in flooring & wall coverings, film & sheets, wire & cable insulation coatings, consumer goods, and coated fabric.

The odourless, colourless, water-insoluble liquid is also used in screen printing inks and as a component of some medical devices like catheters. It is classified as a safe plasticizer and its exposure in humans has been reported to be relatively low. However, it has been replaced in many applications by other HMW phthalates for technical and regulatory reasons. Consequently, it is unlikely that the concentrations and patterns of DPHP in house dust and SPM samples will significantly change over time.

Safety

DPHP is a safer alternative to high phthalates such as di-2-ethylhexyl phthalate (DEHP), which are under scrutiny for their potential reproductive toxicity and suspected endocrine disrupting activities. It is a low-volatility plasticizer with good heat and cold resistance, migration resistance and electrical properties. It is used in PVC flooring materials and tarpaulins, as well as coating plastisols. Its low fogging and volatility also make it ideal for use in UL 7090degC electric wire plastic products.

The safe nature of DPHP, along with its excellent compatibility with polyvinyl chloride, makes it one of the most popular plasticizers on the market. It has been widely adopted by the industry, replacing classified chemicals like DEHP. DPHP concentrations and patterns in dust and SPM samples hardly changed over the study period and remained relatively low compared to other HMW phthalates, such as DINP.

Environmental Impact

The plasticizer Di(2-Propyl Heptyl) Phthalate is a clear, colourless and practically odourless liquid. It is soluble in usual organic solvents and is miscible and compatible with all monomeric plasticizers used in PVC. It is used in PVC products with high temperature requirements like wire & cable, as well as for outdoor applications such as roofing membranes and tarpaulins.

The worldwide consumption of phthalate esters based on phthalic acid is expected to increase moderately. The major phthalates are DEHP, DINP, and DPHP. They are being gradually substituted by higher molecular weight phthalates (HMW) and non-phthalates that do not have a phthalic acid backbone, such as terephthalate-free polymers.

However, despite strict regulatory controls, incidental retention and recirculation of restricted low molecular weight phthalates in society still occur. This is primarily due to product substitution and recycling practices without consideration of the toxicity of the replaced material. The results of the German Environmental Survey (GerES) and the German SPM sampling program (ESB) show that despite a decline in overall concentrations, a change of the composition of the plasticizer pool has occurred in the indoor and outdoor environments.