Japan's Transcendence Chemical Research Co., Ltd., in collaboration with the University of Tokyo, has successfully developed a "super coating" technology that is highly water-resistant and inexpensive, allowing paper materials and paper products to replace plastic containers.
This super coating material does not contain any substances that are harmful to organisms (including humans), and can be naturally decomposed in the environment after being discarded, so it does not burden the environment.
In addition, this coating technology can be applied to a variety of substrates such as pulp molded products, in addition to paper. In addition, the coating contains a large number of nano-voids, so catalysts and chemicals can be added to it, and various functions can be added according to the purpose without destroying the characteristics of the substrate.
The "super coating" technology developed this time uses the sol-gel method, using a low-viscosity coating solution whose main component is methyltrimethoxysilane and a small amount of titanium tetraisopropoxide as a reaction accelerator. The study found that after dipping copy paper or Japanese paper in the coating solution and drying it at room temperature for about 30 minutes, a silica layer about 3 microns thick will be uniformly formed on the surface of the complexly interwoven cellulose fibers (the component of paper) with a diameter of tens of microns.
The reaction takes place spontaneously and rapidly under the catalysis of titanium tetraisopropoxide using a small amount of water adsorbed on the paper and water vapor in the air, so the paper will not deteriorate during the reaction. The formed silica layer has a strong Si-O-Si siloxane bond network and is firmly chemically bonded to the cellulose fibers, so the mechanical strength of the paper is improved.
The coated paper products have a glossy and waterproof surface. After soaking the straws made of coated paper in water for 3 days, there was no change in shape or strength.
This technology has a wide range of uses, including living materials, industrial products, waterproof corrugated paper, pulp molding, agricultural fields such as incinerable mulch, and medical fields such as discardable petri dishes.
