1, the definition of heat shrinkable material
Heat shrinkable material, also known as shape memory polymer materials, these materials such as polyethylene, polyolefin materials such as hydrogen are usually linear structure, through radiation or chemical action into after the network structure, called crosslinking, crosslinked with "memory effect" of the principles and created a new class of functional polymer materials.
The so-called "memory effect", that is, radiation cross-linked polyethylene and other crystalline or amorphous polymer is heated to above the melting point, the grain although the melt, but not a liquidity state, with a kind of rubber elasticity and, when the poly- ethylene expansion, the shape after cooling remain extended state, if this expansion is re-heated to the crystallization of polyethylene melting temperature, this polymer material will be "remembered" from its original shape when not expand and shrink again restored to their original, so called "shape memory effect."
2, the performance of heat shrinkable material
This excellent "memory" properties, can be used to produce heat shrinkable tubing, membranes, and special-shaped material, such heat shrinkable material radial shrinkage of up to 50% to 80%. Shrink main feature is the added heat shrinkable material tightly wrapped in the outer surface of the object, can play the insulation, moisture, seal, protect and follow and so on.
3, the application of heat shrinkable materials
Based on product characteristics, can be applied to energy, electricity, transportation, mining and other fields. Because the material in the process has a simple, reliable, replacement in the role of play in all areas, the traditional challenges of industrial products, with strong market competitiveness.
At present, heat shrink products are: shrink communication cable accessories, heat shrinkable power cable accessories, electronics shrink sleeves, shrink wrapping films, with a complex series of all varieties of heat shrinkable insulation; the value, the heat-shrinkable products now lives in the first radiation processing industry, accounting for radiation processing of about 55% of GDP, although the output index contains the contribution of ¦Ã-ray processing, but the accelerator electron beam processing, heat shrinkable materials industry is the real foundation.
4 Overview of the foreign
Dole and Charlesby 1950 has found that high-energy radiation cross-linked polyethylene and can lead to improved material properties, then, Charlesby and then found the crystallization of polymers cross-linked with "shape memory effect", which laid the foundation of the development of heat shrinkable polymer materials the foundation. In 1959 he Pinner for the Orica (Raychem) the first company to apply for patents polyethylene heat shrinkable tube, thereby opening a new era of this new functional materials, can be said that the United States is a manufacturing company Raychem heat-shrinkable material started radiation processing plant and the combined company, has grown to nearly 8,000 employees, shrinking product specifications or comprehensive development more than 3,000 species of Baghdad, subsidiaries around the world, its annual production value of nearly $ 3 billion. Range of products, widely used in military industry, electronic industry, automobile industry, electric power systems, telecommunications, petrochemical industry and other areas, dominated most of the international market. As the heat shrinkable material widely used in some developed countries have already attracted attention, many Western countries and Asia, Japan, South Korea, also has started production. Such as Japan, Sumitomo Electric, automotive and appliance industries for priority development of a thin tube heat-shrinkable material production, output has hundred million dollars; after Teng warehouse, put the same have begun production. Larger companies have a $ 3M, Westinghouse appliances. South Korea's Venus, the former Soviet Union and Europe the Netherlands, Britain, France, Sweden and other countries have formed a large-scale production, but a single species of these products, Raychem far less comprehensive development ability, lines and more coverage. Heat-shrinkable material market is still in the puberty period, because the heat-shrinkable material is high-tech products, high profits, good benefits, and thus the international competition is intensifying.
5, Overview of China:
Almost simultaneously the domestic and foreign, in the late 1950s established the CAS Changchun of China's first polymer Radiation Chemistry Laboratory, basic research. 1960s began shrinking materials and radiation cross-linking of wire and successfully applied to the "East is Red" satellite. For the development of radiation processing industry, to build China's first radiation test base (today predecessor of Jilin Chemical Industrial Company of radiation), heat shrinkable materials in China laid the basis for development and production.
The early 1970s, Changchun Institute of Applied Chemistry positive commitment to the country "eight three" oil pipeline corrosion engineering work, to carry out a radiation-crosslinked polyethylene film, tape, film studies, used in petroleum pipeline corrosion engineering.
The early 1980s, led by the should be of the joint convergence of the Jilin, Wuhan High Voltage by the Ministry of Water, by the State Science and Technology, commissioned by the Ministry of Water and support the completion of the heat shrinkable power cable accessories attack poor, and promote the use of rapid, Raychem products to break the domination, the high-tech industries in China to promote the formation and development. 80 years in Changchun should be of the production plant, built in 1994, Changchun Heat Shrinkable Materials Co., Ltd. (CIAC), for the industry, large-scale foundation.
Since 1987, domestic production of heat shrinkable products, the number and variety of rapid development. The main reason is the high value of heat shrinkable material manufacturer stimulation; civil, utilities, construction and other needs fully demonstrated the great potential market of new materials; the United States involved in Raychem Corporation, a major impact on the domestic manufacturers, forcing large manufacturers joint a small factory owner and the group, formed a "heat shrink" situation. As the development of historical reasons, mainly confined to the domestic heat-shrinkable materials, communication and power cable accessories cable accessories two series, essentially forming a pattern of two blocks, one represented by Sichuan Shuangliu communications products manufacturer clusters, another CIAC is represented by Changchun power cable accessories manufacturers clusters. According to incomplete statistics, China had more than 300 large and small enterprises, in which the benefits of good quality and has the following 63.
Domestic production of heat-shrinkable material with special accelerator units existing 7 (a total of 10 units using the accelerator, accelerator about 22% of the total). Another 9 both products and production of heat-shrinkable cable production (each accelerator can be considered 10% of the total number of units). Therefore, about 32% of the total working accelerator for radiation heat shrinkable products production.
Although many domestic manufacturers, but with a larger scale and higher levels of only a dozen manufacturers, including the domestic market fundamentals have been several manufacturers, including Raychem monopoly.
1994 National heat-shrinkable material output value reached 500 million yuan, in 1995 nearly 600 million yuan output value, profits and taxes 200 million yuan. At present, heat shrink products are: shrink communication cable accessories, heat shrinkable power cable accessories, electronics shrink sleeves, shrink wrapping films, heat shrinkable insulation with a series of composite varieties; the value, the heat-shrinkable products now lives in the first radiation processing industry, accounting for radiation processing of about 55% of GDP, although the output index contains the contribution of ¦Ã-ray processing, but the accelerator electron beam processing, heat shrinkable materials industry is the real foundation.
