CSR / Environment

Environmental Technologies That Contribute to a Sustainable, Recycling-Based Society

Environmental Technologies That Contribute to a Sustainable, Recycling-Based Society

  • Self-evaluation: ★★★ Achieved more than targeted / ★★ Achieved as targeted / ★ Achieved to some extent
Fiscal 2017 Objectives Fiscal 2017 Achievements Self-Evaluation*
Develop technology for the practical application of recycled plastic material (recovered composite PP*1) Established and put into practical use technologies for improving the properties of, and performing repeated recycling of, recycled plastic material (recovered composite PP).
Adopted for refrigerator handgrips
Priority Objectives for Fiscal 2018 Develop technology that adds extra value (flame retardancy) to recycled plastic material (recovered composite PP)
  • *1 In addition to the main materials, polypropylene (PP) recovered from components with large amounts of metallic, different resin, etc., additives.

Expanding Closed-Loop Plastic Material Recycling Technology

Sharp and Kansai Recycling Systems Co., Ltd.*2 jointly developed closed-loop plastic material recycling technology. This technology enables the repeated recovery of plastic from used consumer electronics products as well as the reuse of that plastic in parts of new consumer electronics products for the Japanese market. This technology has been in practical use since fiscal 2001 and the enactment of the Act on Recycling of Specified Kinds of Home Appliances (Home Appliance Recycling Act) in Japan.

The development of new technologies has enabled Sharp to increase the volume of recyclable plastic year after year. These technologies include the following: (1) a technology for recovering high-purity PP (polypropylene) from mixed plastic parts and parts that contain metal; (2) a technology for improving the properties of recovered PP/HIPS*3 and PC+ABS*4 materials so that their quality is on a par with that of new materials; (3) a technology that gives materials added value by imparting properties such as flame retardancy, weather resistance, and an antibacterial property, with the aim of expanding applications for recycled plastic; (4) a quality-control technology for ensuring optimal quality.

Thanks to the development and introduction of these technologies that integrate everything from recovery to quality control, Sharp has been able to establish closed-loop material recycling to produce high-grade recycled plastic.

Recycling Plastic Recovered from the 4 Types of Home Appliances

  • *2 A consumer electronics recycling company established in Japan with joint investment from Sharp, Mitsubishi Materials Corporation, and four other companies.
  • *3 High-impact polystyrene (general-purpose polystyrene [GPPS] given impact resistance by adding rubber).
  • *4 A polymer alloy of polycarbonate and acrylonitrile, butadiene, and styrene (a resin given new properties as a result of mixing in several types of polymers).
  • *5 Blending multiple types of resins which are uniformly and finely dispersed into one another.
  • *6 A resin given new properties as a result of mixing in several types of resins.

Developing New Recycled-Plastic Material

In fiscal 2017, Sharp developed recycling technology that enables composite materials primarily composed of PP to be recovered from used home appliances, to separate and recover the useful PP in a highly pure form from those materials, and then to reuse this PP in components for new home appliances.

Prior to fiscal 2017, composite materials primarily composed of PP were difficult to recycle, due to the fact that they were mixed together with multiple types of plastic and metals. They were thus used in fuels, miscellaneous goods, daily necessities, and other such items. With this new technology, composite materials primarily composed of PP are finely crushed, and the differences in physical properties (specific weight, shape, etc.) of the materials contained in the crushed powder are used to separate them so that the useful PP can be recovered in a highly pure form. Sharp then uses its proprietary property-improvement technology to process the recovered PP into a material whose properties (physical properties, durability) are equivalent to those of new plastic materials. Further, foreign particle control technology is used to enable some of this material to be used in external components, thereby expanding the scope of application of recycled plastic materials. These recycled plastic materials are put to use in refrigerators sold in Japan as products conforming to the Home Appliance Recycling Act.

For the future, Sharp is developing new technology based on this technology with the aim of giving recycled plastic materials high added value (e.g., flame retardancy, weather resistance, etc.).

Example of Recovered Composite PP Recycled Plastic Usage

Amount of Recycled Plastic Used and Examples of Recycled Plastic Use

Amount of Recycled Plastic Used

In order to increase the amount of recycled plastic that it uses, Sharp is working to expand the number of plastic varieties and Sharp product applications for which recycled plastic is used.

In fiscal 2017, the cumulative total (from fiscal 2001 to 2017) for closed-loop material recycling technology-derived plastic usage reached 16,000 tons.

Amount of Recycled Plastic Used (Cumulative)

Examples of Recycled Plastic Use

Sharp Awarded the 44th (Fiscal 2017) Iwatani Naoji Memorial Award

Sharp was awarded the 44th (fiscal 2017) Iwatani Naoji Memorial Award sponsored by the Iwatani Naoji Foundation for its “Remaining Life Assessment Technology for Home Appliance Waste Polypropylene Recycled Material Using the Degradation Induction Period* Method.”

From left, top row: Research collaborators IoT Health and Environment Systems BU Domestic CS Control Group (Recycling Technology) Engineer Tatsuya Arai, Subsection Chief Akihide Toda, Section Chief Yoko Fukushima (Representative Researcher), Engineer Hiromitsu Ueda, Kansai Recycling Systems Co., Ltd. President Hideyuki Tanba (on loan from Sharp)

A certificate and medal were presented to Sharp on March 7, 2018 at an awards ceremony held at the Industry Club of Japan’s hall in Tokyo’s Chiyoda Ward.

The aim of the Iwatani Naoji Memorial Award is to encourage scientific and technological developments that improve the lives of people in Japan. It does this by recognizing outstanding energy and environment-related technological developments, which also contribute to industrial growth.

Sharp’s “Remaining Life Assessment Technology for Home Appliance Waste Polypropylene Recycled Material Using the Degradation Induction Period Method” quickly performs degradation diagnosis and life improvement assessment of used plastic recovered from home appliance recycling plants. With the development of this technology, the time required for preparation of recycled plastic has been reduced from several months to around 30 minutes, thereby facilitating the mass production of recycled plastic while also ensuring stability of quality.

This award represents positive recognition of the fact that this technology will help in opening up the path for Japan to achieve its crucial goal of turning waste plastic into a recyclable resource.

Iwatani Naoji Memorial Award medal

  • Period over which additives are effective and being consumed.

Remaining Life Assessment Technology Using the Degradation Induction Period Method

While Sharp was working to develop closed-loop material recycling technology for plastic, with the goal of making it possible to reuse all used plastic, attention was paid to the additives that are put into plastic to prevent their degradation over time from oxidation and other processes. These additives undergo oxidation themselves in order to prevent oxidation of the plastic. Also, because the additives degrade before the plastic does (see the figure below), the remaining life of the plastic is determined by the amount of additives which remain in them. In other words, by figuring out how much of an additive has been lost, it is possible to know how much new additive should be put into the plastic to enable it to be reused as component materials in home appliances.

However, performing the measurements and assessments needed to figure this out via conventional methods can take roughly two months, thus rendering such an approach impractical.

Now, thanks to cumulative research and development based on the mass of data and expertise built up over many years, Sharp has succeeded in developing a technology to allow accurate measurement and assessment to be carried out in a mere 30 minutes.

This technology, therefore, makes it possible to reuse used plastic repeatedly.

Deterioration of Plastic with Time

Measurement and Assessment of Recycled Plastic

  Testing Method Temperature Assessment Time
New assessment method

Test sample: Pellet

Remaining life calculated from correlation of the amount of additive consumption and the degradation induction period

210 degrees Celsius

Resin can be heated to a temperature below its thermal decomposition

20–30 min.

Conventional method

Test sample: Test piece

Accelerated testing at high temperature; physical properties measured after arbitrary amount of time

140–150 degrees Celsius

Temperature at which test piece does not change shape

Approx. 2 months

Accelerated testing: Equivalent to 10 years ≒ 1,200 hours (50 days)
Physical properties measurement: 1 day