Get to know di-2-ethylhexyl phthalate (DEHP) and di-isononyl phthalate (DINP).
Di-2-ethylhexyl phthalate (DEHP) is a low molecular weight ortho-phthalate.
Its chemical formula is C6H4(C8H17COO)2.
It is produced by the esterification of phthalic anhydride with 2-ethylhexanol.
It can be said that this substance is a non-volatile, colorless and odorless viscous liquid that is soluble in oil, but insoluble in water.
Due to its low cost and good overall performance, DEHP is widely used as a plasticizer in the manufacture of products made from PVC.
Melting point: -50°C
Boiling point: 250–257°C at 0.5 kPa
Structure of DEHP
DEHP offers good gelation and satisfactory electrical properties and helps to produce highly elastic compounds with reasonable cold strength.
It exhibits relatively good flexibility at low temperatures and some resistance to high temperatures.
However, DEHP is listed by IARC as a human carcinogen.
DEHP has been identified in certain studies as a hormone mimic and a developmental toxin.
In the European Union, DEHP is considered an SVHC (Substance of Very High Concern) under the REACH regulation.
It cannot be used in most products.
It is easily extracted in non-polar solvents (oils and fats found in foods packaged in PVC).
Therefore, the US Food and Drug Administration (FDA) only allows the use of packaging containing DEHP for foods that are mainly composed of water.DEHP is used in applications such as:
DEHP is gradually being phased out for technical reasons such as loss of performance over time, regulations, etc.
It is also being replaced by the terephthalate plasticizers DINP and DIDP.
Diisononyl Phthalate (DINP) is a high molecular weight ortho-phthalate.
Its chemical formula is C26H42O4.
It is produced by the esterification of phthalic anhydride with isononyl alcohol in a closed system.
It is almost colorless, odorless and oily.
It is very slightly soluble in water. However, it is soluble in alcohols, hexane, etc.
It is miscible and compatible with all monomeric plasticizers used in PVC compounding.
Melting point: -43 °C (-45 °F; 230 K)
Boiling point: 244-252 °C at 0.7 kPa
Flash point: 221 °C (°F)
DINP structure
Diisononyl phthalate increases the flexibility and durability of vinyl products.It also performs well at low and high temperatures.
It is less volatile than DEHP.
Its good solubility results in flexible PVC processing properties.
DINP plasticizers are widely used in both interior and exterior applications.
Due to its lower volatility, they are effective in applications where products are exposed to relatively high temperatures and require greater resistance to degradation.
DINP helps vinyl products in the following ways:
DINP is blended with PVC powder by flooring manufacturers to produce soft and flexible end products.
Diisodecyl Phthalate (DIDP) is a high molecular weight ortho-phthalate.
Its chemical formula is C28H46O4.
It is a mixture of compounds derived from the esterification of phthalic acid and isomeric decyl alcohols.
It is a clear, colorless, and odorless liquid.
It is soluble in most organic solvents but insoluble in water.
DIDP is widely used in wire and cable formulations.
It is also used in the manufacture of automotive interior trim.
It is also suitable for coating furniture, cookware, pharmaceutical tablets, food packaging, and many other items.
Melting point: -50°C
Boiling point: 250-257°C at 0.5 kPa
DIDP structure
The plasticizer DIDP increases the flexibility of the plastic/plastic coating.
They are more durable (less volatile, less water-extractable) than DINP. Its good thermal stability and electrical insulation make it a preferred choice for:
However, DIDP's branched alkyl chain structure makes it susceptible to oxidation at higher temperatures, which may lead to degradation of PVC.
It has a lower plasticizer efficiency than DOP.
It must be used in higher concentrations to achieve the ideal plasticizer effect.