The time of issue:2012-03-17 13:31:52 view number:
In recent years, China's starch industry has been rapid development,the important way is modified starch deep processing from scratch, into the initial development phase. At present, China has developed dozens of modified starch and put into mass production. But China's modified starch production with foreign advanced level compared, there is a big gap. Reasonable and adequate development of modified starch to produce, modified starch production technology, performance and applications to make some brief introduction.
Natural starches are carbohydrates. It is composed by the dehydration of glucose units, therefore, the starch can be hydrolyzed by enzyme preparations into glucose.
Commodity-based natural corn starch was a yellow powder, micro moisture content of 12-14%, 1% ash, all dry matter content of carbohydrates.
Natural corn starch powder, granular, uniform particle size, 10-30¦Ì.
Natural corn starch is not soluble in cold water and most organic solvents, therefore, the starch produced in a water slurry, and refined by gravity.
Corn starch can change the following characteristics: solubility, pasting temperature, peak viscosity, back to the old role, gel formation and retrogradation.
Corn starch to degeneration: a chemically modified (esterified); b, water and heat treatment, physical degeneration (Pregelatinized); c, physical and chemical denaturation (dextrin of).
The results of chemical denaturation:
1.2.1 Through the role of acid and alkaline hydrolysis of polymer to the carbon chain to cut short the broken segment, or by chlorine oxidation, the broken section of the carbon chain of the starch polymer cut into segments, so that starch viscosity lower.
1.2.2 The formation of oxide, and the role of chlorine, resulting in dehydration of glucose units.
1.2.3 Esterification on dehydrated glucose ring No. 6 carbon atoms, Peter alcohol-based.
1.2.4 Dextrin of
Dextrin of degeneration by the following methods: a starch in the water mixing (oxidation); b processed into hot dry powder (dextrin); c, a, b, two mixed, such as starch phosphate.
Modified starch can be presented as follows: a granular powder (oxidized starch, white dextrin); b, amorphous powder (yellow dextrin and pre-dextrin of starch); liquid (hydrolyzate, such as glucose).
Modified starch production and application of
One ton of corn starch with 1 to 3 kg of inorganic acid mixed in vacuum and heating effect, the mixture was dried to a moisture content less than 4%, the temperature reaches 120 degrees, and maintain a 2 to 4 hours. When the solubility of starch in cold water up to 35%, stop the reaction. Then, dextrin sharp cooling, and humidity and moisture content of about 10%. The status quo of corn particles in this product can still be identified.
One ton of corn starch with 1 to 2 kg of inorganic acids mixed under vacuum and heating effects, the mixture was dried to a moisture content of less than 2 ~ 3% for 4 hours, and then the mixture over the open bottom of the plate roaster a temperature of 150 degrees, stirring for 4-6 hours, until it was yellow and the solubility in cold water until more than 90%. And then rapid cooling, and humidity to moisture content of 10%. The status quo of corn particles in this product can not be identified.
Corn starch mixed with inorganic acids. Instead, one ton of corn starch in a vacuum and heated under dry to water for 2 to 3% (4 hours), and then calcined at high temperatures (200 degrees) about 5 hours, and then rapid cooling and humidity.
Above dextrin can be used as the adhesive paper labels, envelopes and laminate.
Acid thin paste of starch
Acid thin paste of starch from starch pulp production in the water.
Tons of corn starch mixing in five tons of water, and then the slurry acidification with hydrochloric acid until a considerable amount with the titration method to measure water concentration of 0.2 to 2 so far. Slurry heated to 30 degrees for 16 to 20 hours, and then sodium carbonate and the pH value is equal to 5.2 when the reaction aborted. Washed three times after drying to water for 12 to 14 percent.
Acid thin paste of starch can be used for surface sizing of the textile industry, washing powder, producers adjust the bonding and experience the production of candy point.
Oxidized starch oxidation degree determined by the use.
Per kg of commodity corn starch containing 10 g of chlorine.
Containing starch 12 g chlorine per kg for confectionery production; containing 16 grams per kilogram of chlorine, used for surface sizing of the textile industry; containing 18 to 30 grams of chlorine per kilogram for the textile industry Pulp agent; containing 16 g per kg chlorine hydrogen ethyl starch, used sandpaper production.
Five tons of corn starch mixing in five tons of hot water, the final temperature of 28 to 32 degrees, the starch milk pump into the reaction tank, then within 20 minutes per liter chlorine content of 150 grams of sodium hypochlorite 1000 l pump into the reaction tank. This is per kg starch chlorine content of 30 grams of commodity-type oxidation of corn starch.
Starch, the initial reaction temperature of 30 degrees, due to the heat generated in the oxidation of the final temperature for 42 to 44 degrees; initial pH value of 11.2, the final pH value of 8.5, pH values decreased in the oxidation process of the formation of organic acid's sake. Reaction time of about three hours, when the measured chlorine content of 0 ~ 10ppm, the reaction aborted. And then hydrochloric acid in the batter and to the PH value equal to 5 .. 2, and washed three times before drying.
The starch is industrial production, an important class of modified starch, Color white, easy to gelatinization, low viscosity, retrogradation is weak, the strong adhesive film is good, high transparency and strength of the membrane, widely The sizing agent used in paper industry sizing and adhesives, textile industry.
Acetylation of corn starch and oxidized corn starch
Tons of starch mixing in five tons of water, add 150 kg of sodium carbonate; 30 minutes, add 30 kg of acetic anhydride, 60 minutes and then add 30 kg of acetic anhydride, 1 hours after the starch slurry is heated to 30 ¡ã C, and then oxidized .
The starch is widely used in the paper industry fine paper surface sizing agent, pre-coated and coated.
Tess of alcohol dehydration glucose ring No. 6 carbon atoms in the alkaline slurry with 3 - chloro-2 - hydrogen propyl trimethyl - ammonium chloride etherification agent etherification. The reaction temperature must reach 48 ~ 50 ¡æ, therefore, necessary to sodium sulfite, in order to suppress the gelatinization temperature of starch. Reaction time of about 4 to 6 hours, and then adjust the PH value of 5, then washed three times after drying.
After the end of the cationic etherification reaction can be generated per kilogram of starch containing 16g of chlorine oxidation, the formation of an intermediate viscosity of starch paste.
Compared to starch and anionic starch and other non-ionic, cationic starch solubility, low gelatinization temperature, viscosity can adjust the height, retrogradation, adhesive film is good, by acid, alkali, salt, mechanical shear high shear and temperature affect the stability.
Cationic starch and other starch different, it has the function of starch can not be substituted. The paper recycling industry, mainly for the pulp on the sizing, surface coating, neutral sizing and adhesives; in the textile industry, as colloidal additives, stabilizers, by the swap; in the treatment of industrial wastewater can be used as flocculation agent or anion exchanger; oil drilling mud treatment agent for drilling fluids, given the well fluids and perforating fluid; in industrial materials and construction can be used as vacuum forming of ceramics and glass fiber insulation materials adhesives.