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Special Report

Introducing noteworthy products and technologies developed through Sony Group environmental initiatives. Selected developer interviews also shed light on these promising innovations.

More Durability with Less: Expanding the Possibilities of Recycled Plastic~SoRPlas~

A relentless quest by Sony to reduce consumption of oil, the main component of the plastic that is so vital in manufacturing, has led to the ultimate in recycled plastic—SoRPlas. Here, a Sony engineer who helped develop this special plastic shares insight that may change the way you think about recycled material.

As long as plastic remains vital in manufacturing, we wanted to take action to reduce consumption of oil-based virgin materials.

SoRPlas is made from scrap optical discs and sheets. Pellets of SoRPlas are then treated with a newly developed flame retardant, shown in the container at right.

About 40 km from the heart of Tokyo, engineers at an R&D lab at Sony Atsugi Technology Center 2 develop new materials for use in products. In particular, a barrage of tests is conducted repeatedly to study recycled plastics. Yasuhito Inagaki, in charge of development of SoRPlas (Sony Recycled Plastic), introduces the novel material as he operates test equipment.“This equipment melts and blends the specified raw materials to produce strands of plastic. After the strands are cut and pelleted, the material is formed into panels to check durability and flame resistance.”
Besides being durable, plastic used for home electronics must offer a certain level of flame resistance. To investigate how well new materials perform, engineers test tensile strength and flammability. In flammability tests, for example, a test specimen is burned to see how the flame spreads and how the plastic reacts.
“SoRPlas is treated with a new flame retardant we developed in-house. Its flame resistance derives partly from the CO2 it generates if it does catch fire. Burning also creates tiny holes that help prevent heat from spreading. At the same time, a thin layer of carbon forms, which deprives the fire of oxygen.”
Yasuhito demonstrates by holding a flame to pieces of SoRPlas and ordinary plastic made from virgin material. After a while, the regular plastic ignites and begins to melt. Just as the SoRPlas seems to catch fire, a puff of smoke is emitted and the flame is immediately extinguished. The difference is clear, and it is easy to see the effectiveness of the flame resistance described by Yasuhito.

  • Plastic made with SoRPlas vs. virgin material Conditions: 85°C/80% RH

    Accelerated aging tests demonstrate the superior durability of SoRPlas over flame-resistant virgin material derived from oil.

  • SoRPlas flame resistance compared to that of regular plastic. Right: An even layer o f carbon forms on the surface of SoRPlas when it is burned, blocking oxygen and preventing fire from spreading.

About 25% of the resources used for Sony products are for plastic. Reducing this amount remains a key challenge.

Sony is currently pursuing an environmental plan called Road to Zero, with zero environmental impact as the ultimate goal. A variety of supporting initiatives are underway to curb climate change, conserve resources, control chemical substances, and promote biodiversity. Of these, efforts to conserve resources include steps to phase out the use of oil and other limited resources.
SoRPlas is a new material developed to bring Sony closer to the goal of achieving a zero environmental footprint. In some cases, it is a viable replacement for one of the many types of plastic in use today—polycarbonate (PC) plastic, from which storage media (CDs, DVDs, and BDs) are made, not to mention the body and clear, light-diffusing optical sheets of LCD TVs, and bodies and parts of other electronics. Sony currently uses much PC plastic, both in software and hardware production. Materials engineers at Sony were motivated by a desire to reduce this considerable consumption of PC plastic in many applications around the world, explains Yasuhito.

Regular flame-resistant recycled polycarbonate plastic has a 30% recycled content and is composed of 15% flame retardant. SoRPlas exceeds 99% recycled content.

Recycling PC plastic was a step in this direction. Plastic scrap from manufacturing optical discs and optical sheets for televisions is crushed, washed, and converted to SoRPlas for reuse. What is impressive about SoRPlas is its high recycled content more than 99%. This represents a significant advance over the roughly 30% recycled content of regular recycled plastic.
If SoRPlas is 99% recycled, you may wonder what the other 1% is. This is a small amount of additives such as flame retardant (described earlier) and colorant.
In contrast to conventional flame-resistant recycled PC plastic, which requires an amount of flame retardant magnitudes greater than this, SoRPlas is treated with a new flame retardant that takes up less than 1% of the plastic by volume while offering superior flame resistance. Yasuhito calls this flame retardant the“secret spice” in the recipe for the plastic.
“In fact, the flame retardant was originally developed as an antistatic additive.
Over the course of various tests, we discovered that its flame resistance surpasses its antistatic properties. We might call it serendipity, a lucky outcome of thorough testing.”

Another SoRPlas highlight:
the material itself can be created in brilliant, glossy colors

Other properties of SoRPlas offer some distinct advantages. The material's own color and glossiness eliminates the need for coatings. Omitting these steps in production reduces environmental impact.

SoRPlas also offers other advantages.
First, it can be recycled repeatedly while retaining its original characteristics better than virgin PC plastic does. Each time PC plastic made of virgin material is recycled, it becomes weaker, but SoRPlas maintains original performance even after five cycles. It also holds color well, which eliminates the need for coating or painting. The brilliant, glossy white of some BRAVIA™ sets comes from this material itself, not paint.

In the current BRAVIA™ KDL-22EX310 LCD TV sold in Europe, 98%* of the plastic parts used in the bezel and back cover are made with SoRPlas. Prospects are good for expanded use in a broad range of products, thanks to its superb durability, flame resistance, and recyclability with minimal change, not to mention an expected economic advantage over virgin material.

*Excluding LCD panels

Yasuhito Inagaki

Senior Manager & Distinguished Engineer
Energy & Environment Business Development Div.
Core Device Development Group
Sony corporation

These characteristics give SoRPlas a smaller environmental footprint, with 1/5th as much impact as virgin plastic (in terms of CO2 emissions, in production), according to Yasuhito. But success in development did not come overnight.
“We have been involved in developing recycled plastic for more than a decade, and Sony is now a leading recycler. Our ultimate recycled plastic, SoRPlas, builds on this progress.”
Still, Yasuhito hopes much more can be done with SoRPlas.
“We would like to try SoRPlas in many other product categories. About 25% of the resources we use are for plastic. From this standpoint, we must remain committed to advances in this key field.”

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