Dioctyl Terephthalate (DOTP) – En

  • Chemical Formula: C24H38O4
  • Odor: Odorless
  • Density: 0.98 g/cm3
  • Boiling Point: 400 °C
  • Melting Point: 30 °C
  • Flash Point: 110 °C
  • Vapor Pressure: 1 mmHg (20 °C)
  • Refractive Index: 1.49 nD
  • Solubility (in Water): Virtually Insoluble
  • Molecular Weight: 390.564 g/mol
  • Appearance: Transparent and Pale Yellow Liquid
  • Freezing Point: -50 °C
Plasticizers such as DOTP, DOP, and DINP are commonly used in PVC polymer chains to reduce the crystalline property of the polymer, allowing it to take on a softer, more flexible form. The esters of phthalic and terephthalic acids form well-known plasticizers. When mixed with PVC, these chemicals confer plastic properties to the material.

Due to the significantly lower molecular weights of plasticizers compared to PVC, they tend to migrate into the surrounding environment (migration) through air or contact. This shortens the lifespan of the plastic. Migration of plasticizers is inversely proportional to their molecular weights. Besides molecular weight, another factor influencing migration is the geometric compatibility between the plasticizer and PVC chains.

Despite having the same molecular weight as DOP, DOTP exhibits linear tendencies in its physical structure, making it compatible with PVC polymer chains. Due to this characteristic, DOTP has lower migration compared to DOP. A plasticizer with high migration separates from the structure of the plastic even during production. Therefore, a higher amount of plasticizer with a volatile ratio is needed to achieve the desired hardness. Consequently, when DOTP is used, the loss in gelation ovens is minimized, resulting in a longer-lasting and more resilient product.

Upon examining all physical properties, DOTP stands out as the best plasticizer in terms of both physical and permanent features. It is used in various PVC applications such as synthetic leather, shoes, cables, hoses, and tarpaulins.

Distinctive features of DOTP compared to DOP include:
1. DOTP is not carcinogenic, unlike DOP, which is restricted in use for items in direct contact with humans in many European countries, such as toys, diapers, medical materials, synthetic leather, and water hoses.
2. Due to its different structure from phthalate-based plasticizers, DOTP has very low migration, resulting in materials made with DOTP lasting longer.
3. DOTP has low flexibility due to its structure, reducing the plastic’s brittleness at low temperatures.
4. Its structural characteristics provide self-lubrication, allowing for shorter and less energy-consuming plastisol preparation.
5. DOTP has stable plastisol viscosity, leading to consistent product thickness for days, unlike the variable viscosity of DOP, causing both time and product loss in production.
6. DOTP can be used instead of DINP and DIDP due to its low volatility.
7. The low migration of DOTP prevents unwanted phenomena in PVC-based products, such as “lacquer soiling,” where material adheres to lacquered surfaces.
8. DOTP is a preferred plasticizer in cable manufacturing due to its excellent electrical properties.