He DOTP, Di(2-ethylhexyl phthalate), or by its chemical name di(2-ethylhexyl phthalate), is a general-purpose primary plasticizer that has gained ground compared to DOP. The reason for this is that, although its molecular weight is the same as DOP (390.50 g/mol), it has a "Para" position in the branching of its molecular structure and is therefore considered less toxic. For this reason, DOTP It is considered to be a terephthalum in order to differentiate it in this aspect.
When using a plasticizer, one must consider its polarity with the PVC matrix, its solvation capacity, behavior at high and low temperatures, its volatility, yellowing index, among other factors. DOP is typically used as a reference point to determine the substitution factor when a desired hardness in PVC is required using another plasticizer. DOTP having an approximate factor of 1.03. This means that the DOTP It solvates less, so a larger quantity will need to be added during the mixing process. Furthermore, this results in a longer processing time to obtain a dry mix, allowing the resin time to properly absorb this and other additives.
He DOTP It is preferred for applications requiring good performance at low temperatures without the product becoming brittle or breaking, and it also has a low volatile content. Its permanence is limited at high temperatures, and migration may occur if the formulation is not properly balanced. It is an odorless, crystalline material, sometimes exhibiting a slight yellowing depending on the alcohol used by the manufacturer, which can negatively affect the finished product.
In situations where a highly flexible material is required, preheating is recommended to improve its absorption by the PVC resin, preferably one with a high molecular weight and high porosity. In the case of Plastisol, preheating typically has a different impact on the viscosity of the mixture, so the same behavior cannot be expected when substituting between DOP and [other materials]. DOTP. In any case, the producer must always keep in mind that the melting and gelling properties of PVC change when the plasticizer is changed. This requires making slight adjustments to the processing conditions, such as speed, residence time, and temperatures used.
When seeking to access international markets, it is highly recommended to remove the DOP, as organizations such as the FDA and REACH have banned its use and favored other alternatives based on the final application, such as the DOTP and the DIDP.
It is important to mention that the DOTP It lowers the softening temperature of PVC, which is why it is not recommended as a lubricant in rigid applications. Essentially, it creates bridges between PVC molecules, facilitating chain mobility and thus imparting different and additional properties, such as increased elongation of the finished PVC base product.
It is also interesting that the DOTP It takes approximately 48 hours for the substance to be fully absorbed by the PVC suspension particles. Therefore, it is recommended to allow time for settling and cooling to accurately determine the actual hardness based on the chosen dosage. This is a common and recommended practice in process and quality control.
Another important characteristic is that, although its volatility is minimal, some material loss does occur when exposed to high temperatures. Careful addition is also crucial because failing to respect the order of addition during mixing may allow other additives, such as mineral fillers, to absorb and reduce efficiency. DOTP added, often having to add more than normal to achieve the desired hardness.
Although the DOTP It generally has good compatibility with PVC compared to other plasticizers, but it has low resistance to chemical attack from certain substances such as palm oil, gasoline, and transmission fluids, as these substances tend to extract it, causing a loss of hardness in the finished products in the short term. The use of other plasticizers that meet market requirements is recommended.
If you require technical assistance or are interested in our plasticizer DOTP, feel free to contact us through our website at Chemical Additives of Mexico.