Technical progress
In recent years polyaspartic acid has become one of the focuses in the development of the chemical industry in China. Domestic experts frequently call for strengthening research and development for polyaspartic acid. Starting from 1996 quite a few research organizations such as East China University of Science and Technology, Peking University and Tianjin University conducted lab research. Beijing University of Technology started research in polyaspartic acid in 1998. Fumaric acid was used to synthesize aspartic acid. The conversion rate of fumaric acid was 95% and the yield of aspartic acid reached 92%. Moreover, the relative molecular mass of polyaspartic acid was controllable in the range from 4 000 to 180 000.
In 2000 Desai Chemical Co., Ltd. and State Key Lab of C1 Chemical Technology of Tianjin University agreed to cooperate and jointly developed production technology for polyaspartic acid and achieved its commercial production for the first time in China. In 2002 the polyaspartic acid new product project of Desai Chemical Co., Ltd. passed the appraisal of an expert team. The product was regarded as a new product in China with world-class quality. In 2005 Desai Chemical Co., Ltd., Tongji University and Tianjin Chemical Research & Design Institute jointly formulated the industrial standard (HG/ T3822-2006) for polyaspartic acid.
There are already more than a dozen polyaspartic acid producers in China today. They include Zhongnong Xingtai (Beijing) Biotechnology Co., Ltd., Desai Chemical Co., Ltd., Shandong Zibo Fuju Biochemical Co., Ltd., Shandong Dongying Leadbond Chemical Products Co., Ltd., Jiangsu Baojin Biochemistry Co., Ltd. and Jiangsu Changzhou Huatai Amino Acids Group Co., Ltd. Besides meeting the domestic demand, some of the product is also exported.
Constant increase of market demand
The development of polyaspartic acid in China is not yet mature in either production scale or product marketing. The potential market demand is big and the development prospect is bright. There is a very big development space especially in water treatment and agricultural fertilizers.
L Water treatment
Polyaspartic acid has excellent effects of scale/ corrosion inhibition and dispersion. Polyaspartic acid as a scale/corrosion inhibitor is extensively used in water treatment such as industrial circulation water, boiler water, reverse osmosis water, oilfield recycled water and seawater desalination and especially in water treatment systems with great hardness, great alkalinity, high pH value and high concentration.
Polyaspartic acid is the best amino acid polymers for inhibiting scale formation and also has excellent biocompatibility and biodegradability. Polyaspartic acid is a polyanion dispersant and is a polycarbonate in terms of chemical structure. It is widely hoped to replace non-biodegradable polyacrylic acid and its copolymers which are extensively used in water treatment today. Over the next few years China will become one of the countries with the most rapidly growing demand for water treatment chemicals in the world. Consumption of polyaspartic acid in the water treatment market is estimated to be more than 2 000 tons a year today.
2. Agriculture
In agriculture, polyaspartic acid can be used as fertilizer synergist. It is processed into polyaspartic acid urea, polyaspartic acid calcium superphosphate, polyaspartic acid ammonium bicarbonate, polyaspartic acid compound fertilizers and polyaspartic acid controlled-release fertilizers to promote the absorption of nutrients in crops such as grain crops, vegetables, melons, fruits and flowers. Polyaspartic acid can be used together with many insecticides such as phosphorodithioate, diazinon, malathion and carbaryl to enhance the effect of these pesticides and also increase the output and improve the quality of farm crops.
When polyaspartic acid is used, the utilization rate of fertilizers can be increased by 20%-40% and the consumption of fertilizers can be reduced by 20%. The addition of polyaspartic acid into urea can enhance the effect of urea and increase the yield of grain crops by 20%-30%, the yield of vegetables by 15%-60% and the output of fruits by 30%. The addition of polyaspartic acid in urea production can raise the granulation rate of urea and increase the proportion of granules from 93%-94% to 97%-98%. It can therefore in- crease the qualified product rate of urea and reduce product loss. In addition, polyaspartic acid can also form compounds with heavy metals in soil, effectively replacing the heavy metals and detoxifying the soil.
The usual application of polyaspartic acid is 225g per hectare. China has 134 million hectares of cultivated land and the demand for polyasparfic acid is 30 000 tons a year. Polyaspartic acid, therefore, has considerable potential demand in the chemical fertilizer sector.
With impacts from the global financial crisis, the production and operation of chemical fertilizer producers is seriously affected. Polyaspartic acid chemical fertilizers as substitutes for conventional chemical fertilizers have, however, developed rapidly. The variety that took the lead in large-scale production and large-area application was polyaspartic acid urea. Polyaspartic acid compound fertilizer makers then started large-scale production and won warm applause from farmers. According to initial estimates, the sales volume of the entire polyaspartic acid chemical fertilizers reached more than 1.0 million tons in 2008. The number of polyaspartic acid chemical fertilizer producers increased to more than a dozen. Product varieties also increased from polyaspartic acid urea to polyaspartic acid compound fertilizers, polyaspartic acid high-tower compound fertilizers, polyaspartic acid calcium superphosphate and polyaspartic acid ammonium bicarbonate.
3. Detergents
At least one third of household detergents in China contain phosphorus or polyacrylic acid chelating dispersants. Sewage generated in the production and application of such detergents causes pollution to surface water, rivers and seawater. Polyacrylic acid chelating dispersants reportedly take around I00 years to degrade completely in water systems. Makers of detergent additives, both at home and abroad, have already stopped using phosphate and organophosphate compounds and changed to polyaspartic acid varieties. The demand for polyaspartic acid in the daily chemical sector of China is around 3 000 tons a year.
4. Others
As polyaspartic acid has excellent effect of dispersion in both inorganic compounds and organic compounds, it has also gained applications in the pharmaceuticals, pigments, coatings, leather tanning, inorganic chemicals and oilfield chemicals sectors. Polyaspartic acid can be used to produce protective coatings with high weather resistance and chemical resistance, fast curing finish paints, fast curing coatings directly used in metal substrates and industrial terraces. The use of polyaspartic acid or its salts as tanning agents in leather tanning can help make biodegradable leather. Besides, polyaspartic acid can also be used to produce pharmaceutical carrier materials.
Requirements for environmental protection in textiles are getting more and more stringent. The Eleventh Five-year Program (2006-2010) for the Development of the Textile Sector clearly defines targets for energy conservation and pollutant reduction. According to incomplete statistics, the textiles sectors is the sixth largest waste water "producer" in China, and dyeing/printing waste water accounts for 80% of the waste water emissions in the textile sector. It is reported that polyaspartic acid will very likely become an important raw material for environmental friendly dyeing/ printing assistants and have a bright development prospect.
Polyaspartic acid producers both at home and abroad have strengthened the application dissemination of their products in recent years. Compared with other similar products, polyaspartic acid series products are very competitive and the demand for them will increase constantly.
