PA6 and PA66 are two of the most commonly used engineering plastics in the world. However, when it comes to recycling these two types of plastics, their similarity becomes a problem. This article gives you a brief introduction to PA6 and PA66 and shows technical solutions on how to distinguish them quickly and easily. It starts with the ready-made NIR solution from trinamiX, continues with our customizable Solid Scanner and ends with some thoughts on how an industrial inline solution could look like.

Table of Contents

    What is Polyamide 6 (PA6) and Polyamide 66 (PA66)?


    Polyamide 6 (PA6) and Polyamide 66 (PA66) are two of the most commonly used engineering plastics due to their excellent properties. Both PA6 and PA66 have high strength and stiffness at high temperatures, making them ideal for applications that require durability in extreme conditions. Additionally, both materials have good impact strength even at low temperatures, allowing them to be used in a variety of applications.

    The flow characteristics of PA6 and PA66 make them easy to process into various shapes and sizes. This makes them suitable for a wide range of applications such as automotive parts, electrical components, and consumer goods.

    How much PA6 and PA66 is produced every year?

    The global production of PA6 and PA66 is estimated to be around 3.5 million tons per year. This has made them a widely-used type of engineering plastic.

    How much PA6 and PA66 is being recycled every year?

    The amount of PA6 and PA66 that is recycled each year varies depending on the region and the type of recycling program in place. In general, however, it is estimated that around 10-15% of all polyamides are recycled annually. This number has been increasing in recent years due to increased awareness about the importance of recycling plastics. Additionally, many companies have implemented their own recycling programs for PA6 and PA66 in order to reduce their environmental impact.

    Why is PA6 and PA66 so hard to distinguish?

    Fuse holder for automotive made of polyamide

    The similarity between PA6 and PA66 makes it difficult to distinguish them quickly and easily. This is due to the fact that both materials have similar physical properties, such as density, melting point, and tensile strength. Additionally, both materials are semi-crystalline polymers with a similar molecular structure.

    Summary: Distinguishing between PA6 and PA66 can cause serious issues with recycling.

    Due to their widespread use, large amounts of PA6 and PA66 are produced each year. In addition to this, a significant amount of these materials are recycled annually. The similarity between PA6 and PA66 makes it difficult to distinguish them quickly and easily. How to solve this problem?

    What are established technologies for sorting of materials in recycling processes?


    One of the most established technologies for sorting materials in recycling processes is Near-Infrared (NIR) spectroscopy. NIR spectroscopy uses light in the near-infrared range to identify and differentiate between different types of materials. This technology has been used for decades to sort plastics, including PA6 and PA66.

    What are the main advantages of Near-Infrared (NIR) spectroscopy?

    The main advantages of using NIR spectroscopy for sorting plastics are its accuracy, speed, and cost-effectiveness. NIR spectroscopy can accurately identify different types of plastics in a matter of seconds. This makes it ideal for sorting large amounts of material quickly and efficiently. Additionally, the cost of implementing this technology is relatively low compared to other methods. Learn more about the basics of NIR and how it used in plastic recycling.

    How does a NIR spectra of PA6 looks like?

    The NIR spectra of PA6 is a graph that shows the absorbance of light at different wavelengths. The absorbance is measured in terms of optical density and is typically expressed as a percentage. PA6 will show peaks in its NIR spectra at certain wavelengths, which are indicative of the presence of certain chemical bonds within the material. These peaks can be used to identify the material and distinguish it from other materials.

    How do the NIR spectra of PA6 and PA66 differ?

    NIR spectra PA6 and PA66

    The NIR spectra of PA6 (in blue) and PA66 (in red) differ in that the peaks for each material are at different wavelengths. This is due to the fact that the chemical structures of the two materials are slightly different, which results in different absorbance patterns. Additionally, PA6 has a higher absorbance at certain wavelengths than PA66, which can be used to distinguish between the two materials.

    Why is NIR a good technology to distinguish PA6 and PA66?

    NIR is a good technology to distinguish between PA6 and PA66 because it can detect subtle differences in the chemical structure of the two materials. NIR spectroscopy can measure the absorbance of light at different wavelengths, which allows for the identification of certain chemical bonds within the material. This makes it possible to accurately identify which material is present, even when there are slight differences in their properties.

    We offer 3 technical solutions to differentiate PA6 and PA66 fast and easy


    To solve this problem, trinamiX offers a ready-made NIR solution as well as a customizable Solid Scanner. Additionally, an industrial inline solution could be developed to help with the sorting process.

    trinamiX NIR Solution: easy to use and ready-made portable solution

    Portable NIR Solution by trinamiX

    Easy to use with a modern user interface

    trinamiX’s NIR solution is an easy-to-use product, with a modern user interface that is intuitive and user-friendly, making it accessible to all users regardless of technical skills or experience.

    Plastics PRO application contains over 30 types of plastic

    The product comes with its own portable hardware, containing an integrated database containing over 30 types of plastics, such as PA6 and PA66. Further software solutions, e.g. for textile recycling are available, as well as a reduced database called Plastics LITE containing 5 plastic types most relevant to post consumer waste recycling.

    Multiple languages, high availability

    It also supports multiple languages – English, German, French, Chinese, Spanish, Russian, Portuguese – so users from all parts of the world can operate the device smoothly without any issue. Generally, trinamiX NIR solutions can be sent to your location in Europe within a few days, or to other areas worldwide in roughly two weeks.

    Solid Scanner: Tiny NIR spectrometer able to run any complex data model

    Compact NIR scanner measures powder

    Compact and lightweight design makes Solid Scanner easy to transport

    The compact and lightweight design makes Solid Scanner easy to transport; it is hardly bigger than a computer mouse. It collects the near infrared spectra and store them in the open JDX file format for convenient data analysis.

    Use principal component analyses as the basis for customized databases that fit any specific needs.

    Principal component analyses (PCA) is a powerful tool for quickly and easily distinguishing between different materials, such as PA6 and PA66. PCA is a statistical technique that uses linear algebra to reduce the dimensionality of data sets while retaining most of the information contained within them. By using PCA, it is possible to create customized databases that fit any specific needs.

    Complex algorithms for different materials can be easily developed with the comprehensive software toolbox available.

    Alongside PCA, our software toolbox offers a range of statistical and mathematical methods for data processing, such as LDA. These capabilities give us the ability to build virtually any data model for you.

    This concept makes the Solid Scanner an ideal product to create prototypes for industrial inline solutions.

    HSI camera solutions: Super fast imaging systems for industrial applications

    What are hyperspectral imaging cameras?

    Hyperspectral imaging (HSI) cameras are specialized imaging systems that capture images in the visible and near infrared spectrum. They can be used to quickly identify different materials, such as PA6 and PA66, by analysing the spectral signature of each material.

    High speed and accuracy

    HSI cameras are incredibly fast, with a frame rate of up to 300 fps (frames per second, full frame). This makes them ideal for industrial applications where speed and accuracy are essential.

    ML based software functions for real time processing

    The software functions of the HSI camera are based on machine learning (ML). This allows for real time processing of data, outputting the data stream via standardized industrial interface.



    Distinguishing between PA6 and PA66 can be done quickly and easily using a range of different methods. trinamiX’s Plastics PRO application, Solid Scanner, and HSI cameras all offer powerful solutions for identifying different materials in a fast and accurate manner.

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