Aaron Industries, a blender of recycled materials including recycled PS, PP and PE from post-industrial and post-consumer sources, was able to improve its flexibility and product offering by implementing an optical sorter.
Aaron serves customers in a variety of industries, from household goods to agriculture. The company purchases recycled granules from third-party partners who process plastic waste through grinding, leaching, sink/float sorting and washing. Aaron pre-mixes various regrinds in a proprietary process to achieve the mechanical or aesthetic properties desired by the customer.
Recycled materials are often a mix of different colors that end up being black or gray. For some customers and some applications, this is not a problem. However, for many consumer products, color is very important. Color can differentiate a brand and make it more attractive on the shelf, which influences purchasing decisions. Therefore, by improving color management, a supplier of recycled compounds can extract more value from a given material stream.
“Customers have always asked for color and will always ask for it – or natural, because they want the flexibility to choose the color they want,” says Todd Marchand, vice president at Aaron Industries.
Plastic pellets before and after Aaron’s optical sorting process. Source: Aaron Industries.
In response to customer requests, Aaron Industries purchased and commissioned an optical sorting machine last year. The new machine uses a color camera and LED lighting to separate granulated material by color. Recently, Aaron began full-scale use of the system for commercial truckloads.
For certain streams, the sorter expands Aaron’s capabilities by converting a mixed stream into a stream that is closer to a specific color, or closer to white or natural. “We’re not matching the colors to an actual Pantone,” Marchand explains. “It’s just expanding the palette for what we can do with that particular stream.”
Each sort brings the material closer to a desired color, not completely eliminating the other colors, but bringing them to a level that makes the resin more usable. The new sorting facility allows Aaron to produce variations of red, blue, green, yellow, orange, white, and even lighter shades.
A recycled stream cannot usually be sorted into pure natural material. For example, it can be mostly natural and have a shade that can be dyed or adapted to an application. “It’s difficult to sort something 100%. So many of our products have a greenish or bluish shade that can be overdyed or doesn’t matter much if the customer is making blue or green products anyway,” says Marchand. “But it certainly offers more options for the end user.”
After sorting, which sometimes involves multiple passes, the materials are sent to one of Aaron’s six extrusion lines for blending and pelletizing. Re-blending ensures the customer receives a uniform and consistent product.
The FDA has not raised any objections to Aaron recycling polyethylene and polystyrene, allowing their use in food contact applications. These materials can also be enhanced through the sorting system, allowing Aaron to work with a customer to offer a blend that includes recycled material in a color appropriate for their application.
The company also works with virgin materials, offering blended composites to customers who want to use recycled materials but need virgin materials for sturdier processing and better mechanical properties. Aaron has a minimum batch size for optically sorted material of just 1,000 pounds, with no maximum.
