Since 2010, the University of Manchester physicist Andre Heim and Professor Konstantin Novoselov have won the Nobel Prize in Physics, and graphene has become a new material.
In recent years, the application of graphene in the textile field has become increasingly widespread. The preparation of high-performance textile fibers from graphene and the finishing of textile functionalization have gradually become a research hotspot in the industry.
Graphene fiber has special functions such as antibacterial, anti-mite, anti-heat, anti-cutting, anti-static, anti-ultraviolet, far-infrared heating and cool conduction. It can be widely used in fabrics, garments, home textiles, knitting and other textiles. On March 15-17, at the China International Textile and Yarn Exhibition held in Shanghai, “China's Smart Manufacturing†graphene fiber attracted industry attention.
Graphene "light application" is concerned
Many experts said that at present, the application of graphene is divided into heavy application and light application. Re-application requires a lot of capital investment and long-term development, so that the traditional material such as graphite is replaced by graphene single-layer atomic advantage. The application of olefins in the fields of batteries, semiconductor chips, etc., but such applications are limited by the current technology and the production cannot be rapidly spread, and most of them remain in the laboratory stage.
The light application of graphene is for civilian use, which can be quickly realized and can bring high cost performance to consumers, such as graphene heating and filtration. It is worth mentioning that companies have applied graphene to the textile field.
Graphene has excellent antibacterial properties and low-temperature far-infrared function. When the graphene is finished on the fabric, the antibacterial fabric can be prepared. Compared with traditional inorganic and organic antibacterial agents, graphene has no cytotoxicity, is more suitable for direct contact with human skin, and has a skin-friendly effect.
Lanzhou University professor Bai Yongxiao said that graphene fabric refers to the effective combination of graphene materials and ordinary textiles, while maintaining the basic properties of textiles, while having one or several unique properties of textile products. Graphene textiles have great application prospects in the fields of conduction, radiation protection, UV protection, antibacterial, special protection and smart fabrics.
At present, home textile enterprises have begun to industrialize graphene, and have successfully produced graphene health products that combine super-low temperature, far-infrared, antibacterial and antibacterial functions. They have improved microcirculation and promoted metabolism. Crucial role.
Smart textile field
According to industry sources, graphene has also developed in the field of smart textiles. The reason why the application of graphene to the intelligent textile field is to pay attention to the good thermal conductivity of graphene. Since the electrothermal conversion efficiency of graphene can reach 99%, it has an absolute advantage compared with other hair materials. Secondly, the traditional resistance wire Fever, prone to short-circuit fire, unsafe water, low body comfort, etc. The graphene is embedded in the fiber structure, and the woven fabric can support a safe voltage of 3.7V, and the temperature rise and temperature can be controlled by the App according to the situation. In terms of user experience, safety and comfort are enhanced. In addition to the fast heating rate, it is superior to carbon fiber and electric resistance wire in terms of heat uniformity and heat generation efficiency. As a graphene textile, the soft, not afraid of folding and washable characteristics are superior.
Wang Liming, director of the New Technology Promotion and Application Center of the China Textile Business Association, said that in the textile industry, domestic companies have developed graphene composite fibers and realized industrial production, and are currently in an international leading position.
"As far as I know, there are no companies producing graphene composite fiber in the United States. They focus on more advanced fields such as aerospace and energy storage batteries. China is a textile country with strong scientific and technological strength, so it develops graphite. The olefin composite fiber is incomprehensible and has great application value," said Wang Liming.
Industrialization has just started
However, experts believe that the industrialization of graphene composite fiber has just started in China. Therefore, when Nantong Johnson & Johnson Graphene Technology Co., Ltd. (hereinafter referred to as Johnson & Johnson) exhibited at the China International Textile Yarn Exhibition, it attracted a lot of attention.
Johnson & Johnson has established a research and development team composed of scientists from the United States, the European Union and China since 2009, focusing on graphene industrialization and subsequent application research. After more than eight years of in-depth research, it has made major breakthroughs in the industrial preparation of single-layer graphene and the research and industrial production of graphene composite functional fiber materials. The biggest breakthrough is the significant decrease in the cost of graphene raw materials.
"When we decided to develop the graphene industry, we must firmly control the raw materials in our own hands." Sha Xiaolin, chairman of Nantong Johnson and Johnson, told reporters that when it first entered the graphene field, raw materials were imported from the United States. 500 yuan per gram, more expensive than gold. Today, only 1 yuan per gram."
Johnson & Johnson has been the world's newest graphene raw material preparation technology that has been successfully researched for many years. The biggest progress is the use of intercalation-peeling production process at normal temperature and pressure, which has short production process, high efficiency, high product single layer rate, low cost and production process. Green. "This is also the key to our subversion of raw material costs." Sha Xiaolin said.
Sha Xiaolin said that Johnson & Johnson not only mastered the international cutting-edge technology that allowed graphene fibers to fly into the homes of ordinary people, but also focused on the long-term dream of building an international graphene brand.
At present, Johnson & Johnson has a production line of graphene raw materials with an annual output of 10 tons, and has been operating stably and normal production for more than one year. It is planning to build a production line of graphene raw materials with an annual output of 100 tons. It is also planned to be put into production in May this year.
China is a major textile country in the world, with an annual output of nearly 50 million tons of various fibers, and chemical fiber production accounts for 70% of the world total. The technology and scale of conventional varieties such as polyester and nylon are world-leading, but due to the widespread homogeneity, Problems such as excessive structural structure have led to low industry benefits in recent years, and the transformation of traditional industries such as conventional chemical fiber is imminent.
In recent years, Johnson & Johnson has developed and applied graphene composite fiber as a breakthrough and a high point of graphene application. Therefore, Johnson & Johnson has developed the graphene composite functional fiber and industrialization as the most important topics and tasks, and proposed "7+ 7" development plan, that is, the development of seven kinds of fibers combined with conventional chemical fiber, and seven kinds of fibers combined with special fibers.
At present, Johnson & Johnson graphene composite nylon, polyester and spandex have achieved industrial production, and the research and development of high-strength composite fibers such as graphene composite high-strength polyethylene, aramid and carbon fiber have also made important progress. The extensive promotion and application of graphene composite functional fibers will promote the transformation and upgrading of China's textile industry.
For example, Johnson & Johnson Kerry Graphene Composite Fiber has excellent antibacterial and antibacterial function: it not only has a 24-hour sterilization rate of 99.9% for Escherichia coli, Staphylococcus aureus and Gram bacteria, but also has a strong anti-caries function. Johnson & Johnson Kerry Graphene Composite Fiber has a 24-hour sputum rate of 95% of the first grade (60% for the third grade and 80% for the second grade), as well as strong far infrared heating function, superior UV resistance and heat resistance. Wear-resistant function.
Li Yichun, a professor at the China Graphene Industry Alliance, said that at present, China's graphene industry has more speculation and less industrialization, and accelerating the application of graphene industrialization is the key. To this end, Johnson & Johnson graphene is continuously researching and developing on the production technology of graphene raw materials, and greatly reduces the cost while greatly improving the quality. At present, the cost of Johnson & Johnson graphene has dropped to one-thirtieth of that of foreign products. At the same time, with the low cost advantage of graphene raw materials, the price of composite fibers is closer to the demand of China's textile fiber market.
At present, as a new thing, "graphene is also required to establish market access standards for textile raw materials." Wang Liming said that the national standard for graphene "civilization" is advancing.
"Gravity Die Casting. A permanent mould casting process, where the molten metal is poured from a vessle of ladle into the mould, and cavity fills with no force other than gravity, in a similar manner to the production of sand castings, although filling cn be controlled by tilting the die."
Gravity Die Casting
Sometimes referred to as Permanent Mould, GDC is a repeatable casting process used for non-ferrous alloy parts, typically aluminium, Zinc and Copper Base alloys.
The process differs from HPDC in that Gravity- rather than high pressure- is used to fill the mould with the liquid alloy.
GDC is suited to medium to high volumes products and typically parts are of a heavier sections than HPDC, but thinner sections than sand casting.
There are three key stages in the process.
- The heated mould [Die or Tool] is coated with a die release agent. The release agent spray also has a secondary function in that it aids cooling of the mould face after the previous part has been removed from the die.
- Molten metal is poured into channels in the tool to allow the material to fill all the extremities of the mould cavity. The metal is either hand poured using steel ladles or dosed using mechanical methods. Typically, there is a mould [down sprue" that allows the alloy to enter the mould cavity from the lower part of the die, reducing the formation of turbulence and subsequent porosity and inclusions in the finished part.
- Once the part has cooled sufficiently, the die is opened, either manually or utilising mechanical methods.
Advantages
- Good dimensional accuracy
- Smoother cast surface finish than sand casting
- Improved mechanical properties compared to sand casting
- Thinner walls can be cast compared to sand casting
- Reverse draft internal pockets and forms can be cast in using preformed sand core inserts
- Steel pins and inserts can be cast in to the part
- Faster production times compared to other processes.
- Once the tolling is proven, the product quality is very repeatable.
- Outsourced Tooling setup costs can be lower than sand casting.
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