Functional polymers are sometimes called fine polymers or special polymers, but there is no accurate definition so far. Generally, it refers to polymers and their composites with the function of transferring, converting or storing substances, energy and information, or specifically, it refers to polymers and their composites with the functions of chemical reactivity, photosensitivity, conductivity, catalysis, biocompatibility, pharmacology, selectivity, energy conversion and magnetism on the basis of the original mechanical properties.
Super absorbent resin is a new functional polymer material. It has excellent water absorption and retention function, and can absorb water hundreds or thousands times its own weight, up to 5300 times. Even if it is squeezed, it is difficult to dehydrate, so it is crowned as "super absorbent".
There are many kinds of super absorbent resins, and the raw materials and technological methods used are also different. The main types are polyacrylate, polyvinyl alcohol, vinyl acetate polymer, polyurethane, polyethylene oxide, starch graft polymer and so on. In addition, there are composite water-absorbing materials mixed with rubber. Among the above types, polyacrylate is the most researched and developed. The resin is made of acrylic acid and caustic soda by reverse polymerization. Because the process is simple and easy to operate, the prepared resin has high water absorption and low production cost, so it develops very rapidly.
Super absorbent resin is a kind of white or yellow, non-toxic and tasteless neutral particles. It is different from the physical water absorption of absorbent materials such as sponge, emery cloth and absorbent cotton, and absorbs water through chemical action. Therefore, once the resin absorbs water and becomes an expanded gel, it is difficult to dehydrate even under the action of external force, so it can be used as a water-retaining agent for agriculture, gardens and seedling transplantation. In the planting of vegetables and flowers, spraying a few thousandths of super absorbent resin in the soil in advance can make the vegetables grow vigorously and increase the yield. In afforestation, all kinds of seedlings often dry up and die because of poor storage during transplantation. If the newly unearthed seedlings are treated with super absorbent resin hydrogel solution, their survival rate can be significantly improved. Someone has done experiments on transplanting camellia and coral trees. After water treatment, the survival rate 100%, but without treatment, the survival rate is very low or all of them die. Super absorbent resin can also be used as seed coating agent, which plays a great role in aerial seeding afforestation and early grassland.
Super absorbent resin has the characteristics of high water absorption, good water retention, fast water absorption, strong ammonia absorption and no toxic and side effects. Its most prominent feature is that when it is mixed with chemical reagents such as benzene, toluene, acetone, ether, methanol, ethanol, dichloroethane, chloroform, carbon tetrachloride, acetic acid, etc., it can dehydrate the reagent, but it does not react chemically with the reagent. It absorbs the water in the reagent and becomes a gelatinous substance. If the water-retaining agent that absorbs enough water is separated, it can be reused after drying. Super absorbent resin used in chemical production can greatly improve the concentration, purity and product quality of various chemical reagents. It can replace the rectification tower in chemical production, fundamentally reform the production process, greatly reduce the production cost and achieve considerable economic benefits.
Super absorbent resin can be made into blood-sucking paper instead of medical cotton. The blank can be processed into female sanitary napkins, baby diapers, paper handkerchiefs and napkins. Women's sanitary napkins are easy to carry, hygienic, soft and comfortable, and babies' diapers can be changed overnight. Paper urine bags can relieve some people who have no toilets in public places from the unbearable pain of urinary distension, which is more convenient for some elderly people with decreased renal function and frequent urination or those who are inconvenient to move because of disability. In addition, super absorbent resin can also be used as sludge desiccant, indoor air fragrance, preservative for vegetables, fruits and cigarettes, mildew inhibitor, other industrial oil-water separators, flame retardant, waterproof agent, moisture-proof agent, curing agent and children's toys that expand after water absorption.
Super absorbent resin was first put into industrial production and application in Sanyo Chemical Company of Japan at 1978. At present, the global total production capacity of super absorbent resin has exceeded 6.5438+0.3 million tons/year, among which Japan's Catalyst Chemical Company is the world's largest super absorbent resin production company with a production capacity of 250,000 tons/year. At present, the global demand for super absorbent resin is about 900,000 tons/year, and it is increasing year by year. As diapers and sanitary napkins for babies or adults are becoming more and more popular in Southeast Asia, Central and South American countries, Eastern Europe and other parts of the world, the market demand for super absorbent resins is increasing rapidly, which leads to the manufacturers of super absorbent resins expanding their production or conducting international production. The United States consumes about 300,000 tons of super absorbent resin every year, accounting for about 35% of the total consumption of super absorbent resin in the world. The consumption in Europe is about 200,000 tons/year, accounting for about 25% of the total consumption. Japan's consumption is about 80,000 tons/year, accounting for 10% of the total consumption. More than half of them are used for baby diapers, and others are used for gardening, food, civil engineering and construction. It is predicted that by 2005, the world demand for super absorbent resin will reach about 65,438+200,000 tons, and the average annual growth rate of consumption will be about 4%-5%.
Our country began to research and develop super absorbent resin from the end of 1980s. At present, there are more than one manufacturer 10, with a total production capacity of about 10000 tons/year and an actual output of about 5000 tons/year. The main manufacturers are Fushun Institute of Chemical Engineering of China Academy of Sciences, Lanzhou Institute of Chemical Physics of Chinese Academy of Sciences, Boya Science and Technology Company of Tangshan, Hebei, Shandong Institute of Medical Devices, Jilin Petrochemical Design and Research Institute, Chengdu silicone Research Center of the former Ministry of Chemical Industry, Yingkou Petrochemical Research Institute of Liaoning, Jilin Chemical School High-tech Development Company, Jiangsu Wuxi Hailong Sanitary Materials Company, Hebei Xinao Group Company, Hebei Baoding Hank Resin Factory, and Heilongjiang North Xu 'an Photochemical Factory.
At present, the consumption of super absorbent resin in China is about 20 thousand tons/year, including the consumption of personal hygiene products (sanitary napkins, baby diapers, etc.). ) is the largest, followed by agriculture and forestry. At present, the output of super absorbent resin in China can not meet the actual domestic production demand, and it takes a lot of foreign exchange to import from Japan Jiayou Special Chemicals, Sanyo Chemical and Mitsubishi Petrochemical Company every year. It is predicted that by 2005, the demand for super absorbent resin in China will reach 30,000-35,000 tons, while the current production capacity is only about 6,543.8+0,000 tons/year.