In line with growing awareness of environmental issues, Fuji Xerox has been actively pursuing the recycling of business equipment materials, thus meeting demand for the use of more recycled materials in our products.

For the machine enclosure covers of copy machines and printers, resin materials that contain halogenated flame retardants have been widely used. Now that its use is restricted due to safety and environmental concerns, however, we are now using a resin material that contains phosphorous flame retardants, which is more environmentally friendly. Unfortunately, there has been no recycling method in place for this material since the phosphorous flame retardants accelerate resin deterioration, making it difficult to recycle. Accordingly, Fuji Xerox has been working on technologies that will enable recycling of machine enclosure covers made from this resin and collected from the workplace.

In the most efficient recycling processes, 100% of the collected materials are recycled. However, as the collected resin deteriorates too extensively to be reused as is, it must be combined with a new resin before reuse. Furthermore, the compounding ratio of the collected resin has been limited to only about 10% of the finished product, since increased use of the collected resin makes it difficult to obtain the same strength and flame resistance of new products.

Fuji Xerox has now succeeded in incorporating the collected resin in amounts up to 20% (dry-weight ratio) of the recycled resin, far exceeding the previous ratio. The recycled resin developed by Fuji Xerox has also achieved equivalent or higher levels of strength (Fig.1) and flame resistance (Fig.2), UL94 5VB (1.5mm)*1 as compared to new products.

Fig.1. Comparison of Resin Strength


Fig.2. Comparison of Burning Time:
The time between forced ignition and flame extinction for each resin type is compared. Flame resistance is higher when burning time is shorter.
The selection of new resin and the mixing/molding method of the collected resin with the new resin are very important factors when recycling the collected resin. The importance of these points can be made clear by observing the hammered parts of molded recycled resins in varying conditions. For instance, when the appropriately combined resin is observed under a microscope (Pic.1), voids generated by the hammer shock are relatively dispersed over the entire surface area. However, with other resins, voids are large and mottled (Pic.2). As the shock is absorbed by voids generated inside the resin, we are now able to ensure a similar or higher strength levels for the recycled resin as compared to new products by manufacturing the resin under conditions that generate evenly distributed voids.

Furthermore, it is essential to select an appropriate flame-retardant material. With the existing material, flame resistance was insufficient, as the flame retardant could not be evenly applied to the recycled material. Therefore, Fuji Xerox developed a silicone flame retardant with a special surface modification, and this has improved the dispersibility of the flame retardant and achieved higher flame resistance.

As a result of the appropriate combination of materials, manufacturing, and molding technologies, it is now possible to produce recycled resin for machine enclosure covers that has the same or higher level of strength and flame resistance as compared to new resin, even when incorporating 20% of the collected resin.

Fuji Xerox will continue to pursue and refine this recycling technology as part of its goal to produce environmentally friendly products.

Pic.1		Pic.2
Micrographs of Recycled Resin under Transmission Electron Microscope

[Terminology]
*1 UL94 5VB (1.5mm):
“UL” is one of the safety standards established by Underwriters Laboratories, Inc. in the U.S.
“UL94” is widely used as a measure of the flame retardancy of materials. The highest grades in order are 5VA, 5VB, V-0, V-1, V-2, and HB (e.g. “5VB” indicates that it is the 2nd most flame-retardant material).
The grade is judged based on the result of a combustion experiment that verifies the burnout level of a test specimen after heating a specimen of specified size over a gas burner.