ã€Chinese Packaging Network News】 University of California, Riverside researchers in the laboratory to create a new type of rewriting without ink printing "paper", in the form of glass or plastic film media, based on redox dyes, blue, red, Three primary colors of green, no more than a significant loss in contrast and resolution after more than 20 cycles of recycling. Relevant research results were published on the December 2nd online version of Nature Communications.
Paper was first invented by China and used for a variety of purposes, the most common being writing and printing. In fact, the development and spread of civilization is due in large part to the use of paper as a writing material. According to the survey, 90% of today's commercial information is kept on paper, although a large amount of printed paper is discarded after being used only once. The use of traditional paper, discarded paper (and ink cartridges) is accompanied by a series of environmental issues such as forest deforestation, chemical pollution of air, water, and land, if the paper can be “erased†several times , then this situation can be changed.
According to a report recently organized by the Physicist Organization Network, the experimental leader Yin Yadong, a professor of chemistry at the university, said: "This dye forms the 'paper' imaging layer and printing is achieved by using ultraviolet light to bleach the dye. Erasing 'paper' does not require additional ink printing, making it economically and environmentally feasible. It represents an attractive alternative to conventional paper that can meet the increasing global demand for sustainable development and environmental protection.â€
This novel "paper" is basically a rewritable medium in the form of a glass or plastic film, and letters and patterns can be printed repeatedly, kept for several days, and then erased by simple heating. It has three primary colors: blue, red, and green, prepared by using commercially available redox dyes methylene blue, neutral red, and acid green, respectively, titanium dioxide nanocrystals (which act as catalysts) included in dyes and thickeners, hydrocellulose. (HEC). Mixed dyes, catalysts, and HEC add high reversibility and repeatability to this "paper".
In the writing phase of "paper", the UV light reduces the dye to its colorless state. In the erasing phase, the redox dye restores its original color, i.e., the imaged material recovers its original color by reacting with oxygen in the surrounding environment. It is usually heated to 115°C to speed up the reaction so that the erase process is completed in less than 10 minutes.
The researchers said: “The text printed with this 'paper' has high resolution, is clearly visible, and can last for more than three days under external environmental conditions, which is long enough in practical applications such as reading newspapers. , Its production is simple, the production cost is low, the toxicity is low and the energy consumption is low."
In order to reduce the total cost, the researchers are working hard to increase the use of this "paper" in the laboratory for the purpose of recycling 100 times. And study how to extend the clarity of printed text or images for more than three days in order to expand their potential use and the possibility of adopting multicolor printing.