Biomass Plastic Material Technology

Ricoh has been quick to focus attention on biomass plastics as a material that contributes to preventing global warming while reducing consumption of petroleum, an exhaustible resource. We have been accumulating new technologies and applying them to product materials.

Ricoh has been developing components of imaging devices that utilize biomass plastics as a part of its effort to develop alternative materials while considering the best methods of manufacturing to support a low-carbon and recycle-oriented society.

In 2002, we started to develop biomass plastics with a 50% biomass content(*1)for multifunction copiers, which we applied to interior components for the first time in the industry in 2005. Ricoh continuously made efforts to increase the biomass content of materials and in 2008 was able to successfully introduce components that use materials consisting of nearly 70% biomass content.

Furthermore, Ricoh has been working towards the commercial application of highly-flame retardant biomassplastics that conform to the strict standards of strong fire redundancy and durability that are required for the exterior components of imaging devices in order to expand the use of such materials. In August 2013, we successfully introduced such biomassplastics to the exterior components of the production printer RICOH Pro 8120S/8110S/8100S.

(*1) The ratio of biomass plastics to the total used for components

Advantages and issues with the use of biomass plastics

Biomass plastics utilize the biomass resources of regenerable biological origin. Currently, biomass plastics based on plant-derived materials are in practical use. The plastics are high-polymer materials made of raw materials consisting of starch, sugar, or cellulose contained in plants. One example is polylactic acid, the chemically-synthesized lactic acid that is fermented from starch. Even if CO2 is ejected when polylactic acid is incinerated, it is utilized in photosynthesis by growing plants that are used as materials; the CO2 in the atmosphere does not increase (carbon-neutral). Therefore, it is an environmentally-friendly material that does not contribute to global warming (Figure 1). Furthermore, this material is as strong and rigid as polystyrene. However, for polylactic acid to be used as a material in durable goods, issues related to heat resistance and impact resistance as well as flame retardancy need to be addressed; the material must provide non-flammable parts for electric and electronic devices. Furthermore, issues related to molding techniques for mass production of components have to be addressed.

At Ricoh, with the aim of resolving these issues and paving the way to the full adoption of polylactic acid, we are developing materials technology for applying polylactic acid fermented from non edible materials. Examples include timber from forest thinning and waste wood for use in durable parts. There is also a molding technique suited to mass production that achieves economic efficiency.

image: Circulation of biomass plastics
Figure 1: Circulation of biomass plastics

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Issues for expanding the use of biomass plastics and Ricoh's approach

1. Issues for expanding the applications of biomass plastics to Multifunction Printers

Plastic components comprise 20% to 30% of the weight of multifunction printers. A wide range of applications for plastic components exists. Interior components include interior covers and paper feed trays, while exterior components include covers. Functional components are also present such as fusing units, which require high heat resistance, or optical units, which require high dimensional precision. The properties required of each component differ (figure 2). For instance, exterior components, which use a large amount of plastics, must be fire retardant (non-flammable). Ricoh will remain committed to addressing various issues in responding to applications and will continue to expand their range of applications.

image: Proportion of plastics adopted for multifunction printers based on application and properties required
Figure 2: Proportion of plastics adopted for multifunction printers based on application and properties required

2. Increase in biomass content

Three major issues exist with regard to the increase of biomass content with polylactic acid, a plant-derived crystalline polyester, which Ricoh has applied as materials in imaging devices.
- Crystallinity (degree of crystallization) influences heat resistance and impact resistance.
- Crystallization speed influences molding cycle time.
- It is difficult to secure fire retardancy using polyester.

Traditionally, we coped with these issues by blending a certain ratio of petroleum-derived plastics with polylactic acid; however, doing this meant that we could not increase biomass content (*2) in the way we wanted. The highest content we could achieve was around 50%. To improve the proportion, Ricoh developed new additives jointly with a material supplier. This was done to control crystallinity without mixing petroleum-derived plastics, while ensuring heat resistance and impact resistance. The new biomass plastics have a higher biomass content (about 70%), which is top-class in the industry (Figure 3).
Furthermore, this material can be formed as fast as conventional petroleum-derived plastic materials and can also be mass processed. We first used this material for a manual pocket for imagio MP C2200, which was released in October 2008(Figure 4).

(*2)  Biomass content: The proportion of biomass resources used as the raw material of a plastic component.

Figure 3:Comparison of biomass content using conventional and new methods
(a) Conventional biomass plastics
Biomass content (about 50%)
(b) New biomass plastics
Biomass content (about 70%)
Figure 3:Comparison of biomass content using conventional and new methods

(a)  The imagio MP C2200 manual pocket (b) Installation position on imagio MP C2200
(a) The imagio MP C2200 manual pocket (b) Installation position on imagio MP C2200
Figure 4: A part mounted on the imagio MP C2200 (October, 2008, sold in Japan)

3. Highly Flame Retardant Biomass Plastics

High flame retardancy (resistance to catching fire) is required for exterior components of imaging devices for safety reasons. Under the international flammability standard, exterior components of large devices, including imaging devices, are required to conform to the second level, 5VB of UL94(*3). Up until now, it was a major technical challenge for us to improve flame retardancy from V-2, which is the level required for interior components up to 5VB. By overcoming this issue, we can expect a significant effect in reducing environmental impact through the application of biomass plastics to exterior components making up a large percentage of the total components per unit (Figure 2).

Ricoh has been aware that flame retardancy could be achieved by blending a certain ratio of petroleum-derived plastics with biomass plastics. However, the company decided not to use this method, opting instead to find a solution to improve flame resistance by developing technology jointly with a material supplier. As a result, Ricoh figured out how to control the speed of crystallization, which has led to an improvement in flame retardancy, while at the same time ensuring the strength of the material and even improving formability. The new plastics have a biomass content of more than 40%, conform to level 5VB flame retardancy standards, and also possess satisfactory durability and resistance to heat. In August 2013, these highly flame-retardant biomass plastics were adopted in the operational panel back covers of production printers RICOH Pro 8120S/8110S/8100S(figure 5). As of October 2013, a 40% biomass content was considered a very high percentage for highly flame retardant biomass plastics. This material is expected to reduce CO2 emissions by more than 40%(*4)during the production of materials compared with traditional petroleum-derived plastics.

(*3) UL 94(the Standard of Underwriters Laboratories Inc.), the Standard of Safety for the Flammability of Plastic Materials of Parts in Devices and Appliances testing: the classifications are HB, V-2, V-1, V-0, 5VB, and 5VA (Underwriters Laboratories Inc., standard).

(*4) Ricoh's estimate by comparing with emissions from the production of conventional PC+ABS plastic components.

image: Highly fire-retardant biomass plastic is being used for the back cover of the operation panel in RICOH Pro 8120S/8110S/8100S.
Figure 5:Highly fire-retardant biomass plastic is being used for the back cover of the operation panel in RICOH Pro 8120S/8110S/8100S.

Ricoh's direction in applying biomass plastic to imaging devices

Going forward, in order to achieve Ricoh's environmental target of cutting the new input of resources by 25% from the FY2007 level by FY2020, we will continue to improve rigidity and formability, which are requirements of materials used in larger components, as well as heat resistance and water absorbency, which are essential properties of functional parts, while ensuring durable dimensional accuracy(*5). Through such technological development, we aim to expand the use of biomass plastics (figure 6). In addition, we are working to enhance recycling activities to make a greater environmental contribution in the biomass plastics lifecycle.

(*5) Durable dimensional accuracy: dimensional accuracy that needs to be ensured for multiple years without causing any dimensional changes due to heat/water absorption for the application to plastic components of imaging devices that will be used for more than five years.

Figure 6: Development image of biomass plastics

Figure 6: Development image of biomass plastics

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