Perstorp Introduces Copolymer Carrier in PET Applications to Provide Glass-Like Clarity

Incompatible carrier resins negatively affect the haze, transparency, and overall appearance of transparent PET and rPET products, raising growing concerns as the plastics value chain shifts toward recycled materials and faces stricter regulatory requirements.

Akestra™ is an amorphous copolyester carrier provided by Perstorp, specifically designed for transparent polyester systems. It helps masterbatch producers maintain the optical properties expected in PET and PETG products. Its use in rPET-based solutions depends on validation within specific masterbatches and end applications. Depending on the pigment and formulation, the carrier can support pigment loadings of approximately 20 to 50% by weight. It is also suitable for defined food-contact applications, a factor that has become increasingly important given the applicability of the EU Packaging and Packaging Waste Regulation (PPWR) since August 12, 2026.

Akestra™ combines glass-like clarity with heat resistance and processing versatility. It is compatible with a range of amorphous polymers and can be used for extrusion, injection molding, and compounding.

This makes Akestra™ a versatile carrier platform for functional and color concentrates, specifically designed for demanding transparent applications. Potential applications include masterbatches containing the following:

• Colored pigments

• UV stabilizer

• Anti-block agent

• Antistatic agent

• Antimicrobial agent

• Nucleic acid agent

• Release agent

Akestra™ provides polyester-based carrier options for PET and PETG applications. It helps masterbatch producers formulate concentrates while maintaining the expected optical properties of transparent polyester products. Akestra™ 90 is particularly suitable for PET and PETG masterbatch applications, making it a relevant carrier option for masterbatches used in transparent PET and rPET-based solutions, subject to validation for specific masterbatch formulations and end-use applications.

This is becoming increasingly relevant as converters and brand owners seek to combine a high-quality appearance with greater use of recycled PET.

Contribute to functional performance

Akestra™ is a transparent carrier compatible with PET and rPET, which can also contribute functional performance to the final formulation. Depending on the Akestra™ grade, addition level, and formulation, it can be used to modify melt behavior and reduce melt viscosity. This may help improve the processing and performance of polyester systems.

Therefore, Akestra™ plays a dual role in masterbatches. It efficiently delivers pigments or functional additives and contributes to the performance of the final polymer formulation.

Supports a pigment load of approximately 20 to 50% by weight.

An effective carrier must contain sufficient pigment or functional additives while supporting stable formulation and processing. Depending on the selected pigment and formulation, Akestra™ can support a color masterbatch pigment loading of approximately 20 to 50 wt%.

In masterbatch formulations evaluated for transparent PET food-contact applications, Akestra™ comprises approximately 50 to 80 wt% of the masterbatch as the carrier resin. The masterbatch is typically added to PET resin at levels of about 1 to 3%. The exact dosage depends on the desired color or functionality, as well as the performance requirements of the final application.

This allows you to develop concentrated masterbatches while limiting the total amount of carrier introduced into the final polymer.

Processing flexibility of sensitive additives

Akestra™’s processing characteristics make it suitable for standard polymer processing techniques, including extrusion and compounding. This flexibility is particularly valuable in formulations containing pigments or functional additives that are sensitive to prolonged thermal exposure.

For the selected formulation, processing at temperatures lower than those commonly used for polycarbonate (PC) may help reduce thermal exposure of sensitive additives. You should establish practical processing conditions for the specific formulation and equipment.

Supports food-contact packaging

Food contact applications add another dimension to carrier selection. It is not sufficient for the base polymer alone to be suitable for food contact; every component of the material formulation must be considered as part of the compliance assessment of the finished product.

Akestra™ is suitable for defined food contact applications and is supported by regulatory documentation applicable to the relevant markets and conditions of use. According to Perstorp, this provides a strong starting point for masterbatch producers to develop color and functional concentrates for transparent PET and PETG food packaging.

The timing is particularly relevant. The EU Packaging and Packaging Waste Regulation (PPWR), i.e., Regulation (EU) 2025/40, will enter into force on August 12, 2026. It places greater emphasis on packaging circularity, recyclability, recycled content, and the management of substances concerned.

Therefore, packaging manufacturers and brand owners are increasingly required to provide materials that simultaneously deliver performance, circularity, and regulatory readiness.

Used in polycarbonate applications

Akestra™ can also be used in polycarbonate (PC) applications where transparency, heat resistance, and processability are critical. Akestra™ 100 and 110 provide options for developing PC-based transparent systems. They also offer a polyester route to modify processing, melt flow behavior, and performance.

The performance of masterbatches ultimately depends on factors other than the active ingredients. Carriers that combine polymer compatibility, optical properties, processing flexibility, and food-contact compliance can help masterbatch producers create formulations that meet the evolving requirements of converters, packaging manufacturers, and brand owners.

For transparent PET and rPET applications, Akestra™ helps color masterbatch producers introduce color and functionality while maintaining clarity and compatibility. In the final polyester formulation, it also provides functional benefits, such as improved melt behavior and reduced melt viscosity.