■Biodegradable plastics have been expected to become popular as an eco-material for several years.

■Biodegradable plastics have been expected to become popular as an eco-material for several years.
However, the development of products using this material has not progressed as much as expected.
One reason for this is that the current price of biodegradable plastic is 800 to 900 yen per kilogram, about eight times higher than that of petroleum-based plastics.
However, "that is not really a problem," says Ichiro Sugimoto, president of Sanko Wise Co.
The company developed Cocobatch, a biodegradable mixed plastic five years ago, by blending coconut shell powder with existing biodegradable resins and adjusting the rate of decomposition.
It has been attracting attention as momentum for the use of biodegradable plastics is finally gaining momentum.
Sugimoto, who began his research nine years ago, says, "Plastics, which are now used in large quantities, used to be expensive, but their convenience has made them more popular, and this has lowered their cost.
I think the same will be true for biodegradable plastics.
The biggest challenge is not cost but the usability of the material.
Simply put, it is adjusting the rate of decomposition.
If this cannot be done, applications will be limited and widespread use will be difficult.
Sugimoto began researching biodegradable plastics about nine years ago. Until then, he had been importing and selling coconut culture soil from Sri Lanka, which is used for gardening and other purposes.
The coconut shells that form the basis of the soil are mainly composed of hemicellulose, which is a favorite of microorganisms, and this gave rise to the idea of utilizing the power of nature to introduce it into biodegradable plastics.
In other words, the speed of decomposition of biodegradable resins, which had been fixed, could be adjusted freely by the ratio of coconut shells.
It took four years from the start of research to the commercialization of Cocobatch.
The most difficult part of the process was the process of making the fibrous coconut shells into a fine powder, not to mention the basic matters such as the amount of coconut shells to adjust the degradation rate.
If the powder was too rough, the surface of the thin film would feel rough, making it difficult to commercialize the product.
However, at that time, and even now, the limit of ordinary powdering technology was 70 to 80 microns, and further finer powdering would be costly.
Therefore, we started to develop our own powdering technology, and after much research and development, we succeeded in reducing the size of the powder to 10 microns at a low cost.
This technology is rare in the world, and an overseas patent application is currently in progress.
The advantages of biodegradable resins include low emission of toxic substances when incinerated and low calorific value.
However, the essential advantage is still "biodegradability.
The advantage of "CocoBatch" is its insistence on maximizing this feature.
The excellent degradability of "Cocobatch" has been evaluated in the standard compost biodegradation test of ISO DIS14855 method and the test of the Ministry of Agriculture, Forestry and Fisheries of Japan.
■A variety of biodegradable plastics are currently available from various companies, blending materials to suit different applications.
Examples include Shimadzu's Lacty, Showa Kohden's Bionolle, and Daicel Chemical's Placel.
Cocobatch" custom-blends these various biodegradable resins with coconut shells according to the application, and ships them to manufacturers of processed and molded products.
Coconut shells are imported from Sri Lanka, and the rate of decomposition is adjusted according to the environment and application.
Currently, several tons are shipped annually and demand is increasing.
The mixing of coconut shells has increased the strength of biodegradable resins, making them comparable to polyester and other resins.
Applications are wide-ranging and include agricultural mulch, food waste bags, seedling bots, gardening gloves, hangers, ropes, and mannequins.
For example, the food waste bags produced by Izumi were adopted in conjunction with a food waste composting project underway in Ueno Village, Gunma Prefecture, and distributed to villagers.
Ordinary biodegradable resins take a considerable period of time to fully decompose, leaving fragments of the bags in the compost, but the use of "CocoBatch" enabled rapid decomposition.
Similarly, seedling bots have been commercialized.
Although there has been an increasing trend toward commercialization of products using biodegradable resins, commercialization of products other than thin film products has been difficult because of the difficulty of decomposition.
However, "Cocobatch" overcame this obstacle.
One example is the "EcoBerm Pot," a seedling-growing bot developed by NK Kogyo.
Biodegradable resins that can withstand practical use have finally appeared.
Since the beginning of this year, we have received an increasing number of inquiries, including from overseas, and companies that had been hesitant to commercialize biodegradable resins are beginning to pay attention to them," says Sugimoto.
Currently, biodegradable resins are expensive, but they are expected to be an important solution for reducing environmental impact.
If all plastics are switched to biodegradable resins, it will be the best option for the environment," says Sugimoto.