Professor Yasunori Taga of Chubu University and others have developed a new thin-film material that can reduce the windows of automobiles and buildings to nearly one-tenth.The hardness of the thin film is three times that of glass, and it is a multifunctional film that shields ultraviolet light by 10% or more, and is expected to lead to significant energy savings.
Generally, automobile windows are made of inorganic glass.The weight of a car window is about 5% of that of a normal car body.If the weight of this window can be reduced to about 10/1, it will greatly contribute to the weight reduction of vehicles due to the electrification of automobiles.Currently, in research on improving the hardness of the glass surface, there is a problem that a hard CeO2 (cerium oxide) is formed on the surface, but it is brittle and many cracks are generated due to deformation.
This time, we have developed a thin film material and film formation technology for CeO5, which is a mixture of 15 to 2% by volume of fluororesin PTFE (polytetrafluoroethylene). It was thought that the mixing of PTFE would block ultraviolet light by 80% or more, maintain flexibility three times as hard as glass, and significantly improve the occurrence of cracks due to bending.
In the experiment, a CeO2-PTFE film was formed on the glass surface using argon ions.The hardness of the surface has improved about 2.8 times.The property of repelling water (water repellency) was high even after film formation, and the contact angle of water droplets, which is an index, was 90 degrees or more.In addition, the transmittance of visible light is as high as 80% or more, and the shielding rate of harmful ultraviolet light is as high as 80% or more, both of which have cleared the automobile specifications.
In addition, an experiment to form a film on a plastic sheet has started.When a film is formed using polycarbonate (PC) or polyethylene terephthalate (PET), the hardness of the PC is improved by about 8.9 times, and that of PET is improved by about 4.3 times.There was no deterioration due to weathering test conditions for automobiles.We will replace the glass with plastic and aim for a window that weighs one tenth.
The developed CeO2-PTFE film can be applied not only to automobiles but also to windows of buildings, and it is said that it will develop lightweight and inexpensive window material mass production technology for practical use and an efficient manufacturing method for price reduction. ..