One of the main challenges in adopting rPET at scale is ensuring consistent visual and mechanical quality. Compared with virgin PET, recycled PET can show variation in color, intrinsic viscosity, and other material properties, which can complicate processing and quality control for packaging manufacturers and brands.
In this blog, we look at the sources of this variability and what it means in practice for processing and consistency, as well as the role additive technologies can play in supporting the circular plastics economy.
Many PET recycling challenges originate at the polymer level. During repeated recycling cycles, polymer chains degrade and shorten, reducing strength and processability. A consistent issue is recycled PET discoloration, particularly yellowing, caused by residual inks, adhesives, colorants, and polymers from labels and caps that degrade during heat exposure.
Beyond color, rPET may suffer from black spots due to degraded contaminants, haze that reduces transparency, and intrinsic viscosity variation that directly affects mechanical strength and processing stability. These behaviors do not reflect “flaws” in rPET but rather the reality of a circular material that has been collected, sorted, cleaned, and reprocessed many times. Understanding these dynamics is key to getting the best performance from recycled PET in modern applications.
While traditional mechanical recycling and deposit-return systems remain central to PET circularity today, a new wave of underutilized but promising technologies is emerging. Some innovations are not yet widespread but are gaining traction and may soon redefine how PET is recovered, processed, and reused at scale.
Chain‑support additives such as Holland Colours’ ViscoBoost help restore intrinsic viscosity (IV) in rPET, directly addressing polymer chain degradation. CircStab®, our latest stabilizer, reduces further degradation as rPET undergoes new melt cycles. To address visual challenges, Holland Colours introduced TintMask®, enabling effective rPET color neutralization while remaining optimized for recycling streams.
Together, these additive technologies improve both appearance and functionality, enabling high-quality, recyclable PET packaging even at higher rPET content levels.
A key concern in sustainable PET packaging is ensuring that performance enhancements do not compromise recyclability. In our Factory of the Future eBook, we detailed that functional additives must not disrupt recycling systems or food-contact safety and must meet regulatory and recycling authority requirements.
Holland Colours’ formulations are developed in line with RecyClass and APR guidelines, ensuring that performance improvements support circularity, providing the industry with peace of mind. Through early-stage collaboration and close monitoring of global regulatory developments, Holland Colours helps customers achieve high-performance rPET packaging while remaining compliant and recyclable.
As demand for rPET grows, improving material consistency and maintaining recyclability will remain key priorities for the packaging industry. By addressing intrinsic viscosity loss, thermal degradation, and discoloration, functional additives unlock rPET’s true potential as a reliable and attractive alternative to virgin PET. When designed according to recognized recyclability standards, these solutions strengthen both material performance and circularity, supporting the future of sustainable PET packaging.
👉 Turn rPET challenges into competitive advantages. Get the Factory of the Future eBook for practical insights on rPET performance, recyclability, and technologies enabling reliable, high-quality PET packaging.