PET / PBT / PET-G
The right polymerization method to get the best result.
Those who want to obtain the best result, usually choose the most promising method that they are familiar with. Our specialists can tell you exactly which polymerization method is most suitable for your application. The selection of the polymerization method and the design of the plant also take into account commercial considerations, and the further processing and production depth desired by each individual customer.
EPC uses the method appropriate to the particular chemical properties to convert (polymerise) low-molecular compounds (monomers) into high-molecular compounds (polymers) by radical, ionic or Ziegler-Natta polymerization [PE, PP, PS, PVC, PAN), polycondensation (PET, PBT, PC, PA), or polyaddition.
Solution, precipitation, emulsion, suspension or bead, or melt polymerization is used depending on which method is most suitable for the application and the modification of the desired polymers.
Our polymerisation methods for polyester
Polyethylene terephthalate (abbreviation PET) is a thermoplastic material from the polyester family produced by polycondensation. PET has a wide range of applications and is used, among other things, for the production of plastic bottles (PET bottles), films and textile fibers.
PETG is a glycol-modified PET that is characterized by its particularly high transparency and low viscosity.
PBT is a good electrical insulator whose properties are little affected by water absorption, temperature and frequency. The permeability to CO2 is significantly higher than the permeability of PET, the resistance to chemicals and weathering and the burning behavior are comparable.
Our product brochure
EPC – Polyester Verfahren
Polyethylene terephthalate (PET) is probably the most important polyester. It is obtained by an esterification reaction between ethylene glycol (MEG) and terephthalic acid (PTA) to produce the low viscosity monomer in the first stage. The esterified material is then transformed into a high molecular polymer in a polycondensation reaction.
The PET polymer is a transparent, lightweight, strong, safe, shatterproof and recyclable material. PET in its natural state is colourless and semi-crystalline. Depending on the processing method, the PET can be semi-rigid to rigid, and it is also especially light in weight. PET makes an excellent gas and moisture barrier.
PET resin is also very sustainable as it is recyclable. It is by far the world’s most recycled plastic. PET can be recycled many times – and used in food applications, personal care products, carpets, clothing and many other products.
As well as developing and constructing PET plants, EPC also offers a number of tried and tested technologies it has developed in-house, that restore PET plants to profitability. EPC PETvantage® is a patented, customer-orientated revamping and de-bottlenecking process that meets your need to maximize plant profitability with minimal retrofitting costs and the shortest plant stoppages. EPC engineers have succeeded in converting a textile fibre plant to food-quality PET bottle grade chips, and at the same time they increased the capacity from 440 to more than 1,000 tons per day. It was, and still is, the world’s largest PET plant revamp – “Made by EPC”.
The PET-G belongs to the family of PET and is commonly defined as glycol modified polyester. It is produced by partial replacement of the ethylene glycol (MEG) with CHDM (1-4 Cyclohexane-dimethanol) during the PTA esterification reaction. The usage of CHDM as a co-monomer enhances specific properties of the polymer, and compared to PET, the PET-G polymer offers the following advantages:
- Inability to develop crystalline haze. This leads to high transparency (glass like clarity), making it suitable for packaging of high clarity requirements, e.g. packaging for medical devices.
- Outstanding thermoforming properties, This allows extreme draw definition, thus modern, thin-wall containers/products with demanding shapes can be produced
- No yellowing in molding due to high thermal stability
- Superior chemical resistance – Thus making PET-G suitable for a wide-range of application e.g. containers, electronics, food and medical packaging.
We offer a wide range of industrial solutions for producing quality PET-G polymers:
- Turnkey delivery of a PET-G Production Facility
- Conversion of PET Production Facility to produce PET-G
- Revamping of existing PET Production Facility to produce both PET and PET-G
- Turnkey delivery of CHDM Hydrogenation Plant for the production of quality CHDM co-monomers (Linked to EPC’s CHDM Hydrogenation Technology)
Like polyethylene terephthalate, polybutylene terephthalate is a derivate of terephthalic acid. The two compounds possess practically identical properties. On account of its more favourable cooling and process behaviour, PBT is particularly suitable for injection moulding processes. It is used for housings of electrical equipment, in motor vehicle components, such as plug-in connectors, and in many other applications.
EPC insidePBT is an in-house software development that gives plant operators substantial advantages in PBT production.
The patented reactor design has hydraulically driven shafts and prevents leaks in the vacuum range. A high level of plant safety is ensured because the hydraulic units do not have to be mounted directly on the shaft. It also has redundancy to avoid outages. The transesterification system is designed for easier and stable process control. The result is high profitability, because reduced downtimes increase availability, and the plant delivers consistently high product qualities.
A substantial quantity of THF is produced as a by-product of the PTA-based process. It can be sold at an attractive price after treatment to improve its quality and purity in the integrated recovery plant. This also shortens the amortization time and increases the profitability of the entire plant.
For commercial reasons, the DMT-based process is hardly ever used, because the by-products cannot be processed at an economic price.
Ingenious process control enables the BDO consumption to be minimized, which drastically reduces not only raw material and energy costs but also the pollution caused by emissions.
Polycarbonatanlage in Ningbo, China
Polycarbonatanlage in Ningbo, China
• Process Technology
• Engineering Package
• Key Equipment delivery
• FAT Quality Control
• Supervision of Installation, Pre-Commissioning and
• Recipe Development
• Product Optimization