DOTP / PLASTICISER PLANTS

DOTP plasticiser plants are process plants for the industrial-scale production of dioctyl terephthalate (DOTP), a plasticiser that gives flexibility to PVC and other polymers. Plasticisers make PVC, rubber and many thermoplastics easier to process and modify their flow behaviour. They do not react chemically with the polymer; instead they are physically incorporated between the polymer chains and make the material flexible. They are therefore far more than simple additives such as pigments and fillers: they are key components that determine the physical properties of the polymer.

What Is DOTP?

DOTP (dioctyl terephthalate, chemically bis(2-ethylhexyl) terephthalate) is widely used as a general-purpose primary plasticiser. With high compatibility with PVC and good processability, DOTP can replace ortho-phthalate plasticisers and, in most formulations, substitute for them directly. Thanks to its low volatility and low migration, it is the primary plasticiser in many PVC applications, especially where tensile strength and easy processing are required.

Properties of DOTP Plasticiser

• Plastisol viscosity is stable and changes little over several days, which gives a product of more uniform thickness.
• Its structure gives it self-lubricating behaviour, so plastisols can be prepared in less time and with less energy.
• Its low volatility allows it to be used in place of DEHP (DOP).
• As a linear terephthalate (para-phthalate) ester rather than an ortho-phthalate, it has low migration, so materials made with DOTP retain their properties for longer.
• Unlike certain ortho-phthalates, whose use in Europe is restricted, mainly because of reproductive toxicity, in products in direct contact with people such as toys, childcare articles and medical devices, DOTP is not subject to these restrictions. Products can be labelled ortho-phthalate free.
• Its low migration largely prevents lacquer contamination, the problem of PVC products sticking to lacquered surfaces.
• Its linear structure provides good low-temperature flexibility and reduces the brittleness of the plastic in the cold.
• Its good electrical properties make it a preferred plasticiser for cable manufacturing.

DOTP Plasticiser Production Process

DOTP is usually produced by esterifying purified terephthalic acid (PTA) with 2-ethylhexanol in the presence of a catalyst, while the water formed in the reaction is continuously removed from the system. A typical DOTP plasticiser plant comprises the following units:

• Raw material receiving and storage: powder feeding system for PTA, storage tanks for 2-ethylhexanol
• Agitated esterification reactor with thermal oil jacket or coils
• Column, condenser and water separator to remove the reaction water
• Vacuum stripping unit to recover excess alcohol
• Neutralisation, washing and drying vessels
• Decolourising and filtration unit
• Product storage tanks and filling unit

Turnkey DOTP Plasticiser Plants by Makfen

Makfen designs DOTP plasticiser plants for the required capacity and product quality, and also takes environmental parameters such as energy efficiency, alcohol recovery and emission reduction into account. All stages, including engineering, manufacturing, installation, instrumentation, piping, insulation, electrical installation, performance testing and commissioning, are carried out on a turnkey basis. Stainless steel process equipment is manufactured at the Dilovası facility, and carbon steel equipment and industrial systems at the Gebze facility.

• Design and manufacture of pressure equipment in line with the PED 2014/68/EU directive and EN 13445 / ASME VIII
• Material selection to suit the process conditions (AISI 304L/316L stainless steel or carbon steel) and use of certified materials
• Heating via thermal oil jackets or coils, with thermal insulation
• Impellers, baffles and mechanical seals suited to the product
• Vacuum-rated reactor and column construction
• Ex-proof motors and instrumentation, PLC/SCADA automation
• Complete operation and maintenance documentation

Contact Makfen for information and a quotation for a DOTP plasticiser production plant.