Best Practices for Measuring the Color of Recycled Pellets

Plastic recycling is essential as the world continues to emphasize sustainability. Recycled plastic pellets from post-consumer and industrial waste offer value in various applications, including traffic cones, plastic chairs, detergent bottles, trash cans, and flower pots. 

Ensuring consistent color in products made from reprocessed materials can be complex. Here at HunterLab, we offer a range of solutions to measure the color of recycled pellets for precise results.

Challenges in Measuring Recycled Materials

Quantifying color in recycled plastic pellets presents unique challenges, such as:

• Material variations: Recycled pellets contain plastics from different sources, resulting in color variations. They are often blended to achieve a desired color. Color measurement can help ensure consistent blending ratios and a uniform final product color.
• Contamination: Foreign materials present in recycled pellets can affect color measurement accuracy. Implementing measures to minimize contamination in recycled pellets can improve color consistency.
• Physical form: Recycled pellets vary in size, shape, and opacity, affecting how light interacts with the material during measurement. These properties demand the right equipment and measurement methods for precision and consistency.

Best Practices for Precise Color Measurement

Spectrophotometers/colorimeters are the industry standard for precise color measurement. These devices analyze how light interacts with a sample and quantify the intensity of wavelengths across the visible spectrum to translate color into numbers. The following best practices will help you make the most of this technology to support your goals:

• Prepare and present samples accurately and consistently: It is crucial to maintain consistent sample preparation. Per ASTM D6290-19, operators must use a clean, optically clear and scratch-free sample cup filled to a sufficient depth to ensure effective opacity. Additionally, covering the sample cup with an opaque cover is crucial to block ambient room light and prevent external interference during measurement.
• Measure across a large area: The larger the sample area measured, the more precise and repeatable the results. Refer to ASTM D6290-19 Standard Test Method for Color Determination of Plastic Pellets for guidance on proper measurement methods. Specifically, the standard recommends taking three separate measurements using a "dump-and-fill" technique with fresh pellets to ensure an accurate and representative average.
• Determine the relevant color spaces: Choose a shared color space to establish communication throughout the production chain.
• Leverage color quality control software: Ensure your spectrophotometer integrates with or includes built-in color quality control software. This technology allows you to compare the color of your recycled pellets to target specifications or predefined color ranges.

Agera L2: Next-Gen Innovation for Measuring Plastic Pellets

HunterLab's Agera L2 spectrophotometer is next-generation equipment designed to address the challenges of color measurement in recycled pellets head-on.

Capturing Data Across an Industry-Leading Surface Area

This spectrophotometer/colorimeter boasts the industry's largest area of measurement at 2 inches — 4x to 16x larger than other equipment. As a result, operators can capture more comprehensive data across multiple pellets in a single measurement. Doing so reduces variability in measurements from smaller sample sizes and minimizes the impacts of individual pellet color differences.

Handling Varied Materials With Specialized Color Measurement Modes

We've engineered the Agera L2 with specialized measurement modes that deliver tangible value in plastics manufacturing and processing:

• Dark Performance Mode: This mode offers 6x the measurement precision on samples with less than 20% reflectance, making it ideal for black, deep blue, and dark gray or brown plastic pellets.
• Total appearance quantification: Our innovative spectrophotometer includes measurement for total appearance, so you can understand how texture effects may influence color perceptions.
• Certified Grade ‘A’ CIE D65 illumination: This feature allows evaluation of appearance under true daylight conditions for consistent color data benchmarking.

Supporting Optimal Pellet Presentation With Specialized Design and Accessories

Reduce the measurement discrepancies associated with pellet sample presentation and orientation. Specially designed pellet sample cups and opaque covers are available to simplify consistent sample volume and handling. Plus, the Essentials TotalView 360° Auto Rotator Accessory automatically repositions samples at specified degrees and time intervals, eliminating the need for less precise, manual rotations. An onboard, high-definition camera with sample preview technology further reduces the potential for operator errors and inconsistencies in presentation.

Promoting Higher Efficiency and Sustainability

Our Agera L2 spectrophotometer/colorimeter is designed to support your production efficiencies and sustainability goals.

This equipment promotes high-volume color QA workflows, with readouts displayed in under 3 seconds. Onboard Essentials L2 software transforms the device into a fully self-contained color workstation, with no PC hookup required for analysis. Operators can connect keyboard and mouse via USB ports and a monitor through HDMI if preferred. USB ports also empower fast data migration, while built-in Ethernet connectivity allows direct data transmission to LIMS and SPCs. With 32 GB of storage, you'll also have quick access to up to 4 million historical records with images.

Measuring the color of recycled pellets can help you reduce your facility's environmental impact. Our spectrophotometers offer an objective way to test the color of recycled plastics before mass production, allowing you to minimize waste that could end up on landfill sites. Plus, maintaining sustainable manufacturing practices helps you achieve governance objectives. 

Explore Color Measurement Solutions From HunterLab

As an industry leader for over 70 years, HunterLab is a trusted partner for high-precision color measurement solutions and software. Our innovative spectrophotometers/colorimeters and easy-to-use technology help the world's plastics manufacturers control their color quality and consistency, even as variations in raw materials occur.

Contact us today to request a quote for color measurement equipment or get expert advice for your specific needs.