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yet2 client seeks technology related to colored materials whose color changes (decolors) by external stimuli.



Due to recent demand on sustainability, it is recommended that plastic materials be recycled. However, it is difficult to remove colored components from plastic materials and recycle them as transparent plastics in the waste treatment with various colored materials mixed together. The actual recycled plastics are often colored, and their reuse is limited to applications such as clothing textiles and plant pots, and many used plastics are burned as an energy source.

Therefore, this company is looking for the following technologies that change the color of plastics and improve recyclability:

  • Technology that can remove or change the color of colored materials at the end of the product life cycle (after use)
  • Technology that decolor the coloring materials when you want to erase the color


Current status:

Plastic Coloring Technologies can be roughly divided into the following two types.

  • Kneading coloring materials when raw materials are melted
  • Apply coloring materials on the surface of plastics


There are 2 common existing Decoloring Processes:

  • Color of waste plastics colored with Coloring Technology 1 above are usually removed by dissolving in an organic solvent and passing through an adsorption tower to adsorb the colored components.
  • Color of waste plastics colored by Coloring Technology 2 above are usually removed by washing the colored material with an organic solvent.


Desired outcome of the solution:

The company would like to find “technologies that change color (decolors) by external stimulus” as a new decoloring technology.

Here are some examples.

  • Technology that can remove or change the color of a colored material at the end of the product life cycle after the product is used (If absorbent wave length of visible light is shifted by external stimuli, we are interested in such technology even if the color does not fade.).
  • Technology that is able to change the chemical structure of coloring materials when you want the color to fade.
  • The type of external stimulus can be anything such as heat, light, electromagnetic waves, pressure (physical force).  However, color recovery should be avoided under normal operation.

However, besides “technologies that change color (decolors) by external stimulus,” they are also interested in new decoloring technologies which remove the coloring material from plastic films or containers that could be applicable for the above-mentioned Decoloring Processes.

Recognized solutions:

They recognize leuco dyes as a color erasing technology;  they want to find other technologies. However, if you have a unique leuco dye, they are interested in it.

Possible solution areas:

  • Chromism (photochromism, mechanochromism, etc.)
  • Leuco dye


It is assumed that there are many companies and research institutions developing relevant technologies in Europe, where people are active in creating a sustainable environment.



The information they would like to obtain for the initial evaluation is as follows:

  1. Substance / Name of the discoloration technology
  2. Development stage
  3. Mechanism of color change or discoloration
  4. Comparative value proposition (comparison with competitive technologies or superiority)


  • They prefer to find coloring materials the color of which can be faded in or on the surface of plastics.
  • They are interested in color changing materials with heat such as thermochromic dyes
  • When the color material is decolored with a change in the chemical structure of the coloring material, such colorless compound with newly formed structure can remain in the plastic substrate.
  • They are also interested in the technology of washing plastics or colored materials, or the technology of separating colored materials after depolymerizing plastic films.

There is no constraint or limitation in a type of plastic substrate.

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