13/08/2014
Chinese name: hydroxy propyl methyl cellulose
Chinese alias: HPMC; Hydroxy propyl methyl cellulose
English name: Hydroxy Propyl Methyl Cellulose
English alias: HPMC
Two main purposes
: 1. The construction industry as a cement mortar water retention agent, retarder, make the slurry pump. In plastering mortar, gypsum material, putty powder or other materials as a binder, improve the workability and extend the operational time. Used as the adornment, stickup ceramic tile, marble, plastic paste enhancer, can also reduce the dosage of cement. Water retention properties of HPMC to paste in the daub after will not crack by dry too fast, enhance strength after hardening.
2. Ceramic manufacturing: widely used as binder in the ceramic product manufacture.
3. Due to: in due as a thickening agent, dispersing agent and stabilizer, in water or organic solvents have good intermiscibility. As the paint remover.
4. The printing ink: in printing ink industry as a thickening agent, dispersing agent and stabilizer, in water or organic solvents have good intermiscibility.
5. Plastic: as forming mold release agent, softener, lubricants, etc.
6. Polyvinyl chloride (PVC) : do dispersing agent in the production of PVC, PVC suspension polymerization preparation main auxiliaries.
7. Other: this product is widely used in leather, paper products, fresh-keeping and textile industry etc.
8. The pharmaceutical industry: the coating material; Membrane material; Slow-release preparation speed polymer materials; Stabilizing agent; Suspended aid; Tablet binder; Increases the gooThe physics properties of 3
Hydroxypropyl methyl cellulose molecular formula
Soluble in water and most of the polar c and appropriate proportion of ethanol/water, propyl alcohol/water, ethylene dichloride, etc., in the ether, insoluble in acetone, ethanol, in the cold water swelling to clarify or slightly turbid colloidal solution. Aqueous solution with surface activity, high transparency, stable performance. HPMC with characteristics, thermal gel product aqueous gel precipitation is formed after heating, cooling and then dissolved, different gel temperature, different specifications of the products. Solubility with viscosity changes, the lower the viscosity, solubility, the greater the HPMC its properties have some difference of different specification, HPMC dissolved in water is not affected by PH. Granularity: 100 mesh passing rate is more than 98.5%. Bulk density: 0.25 to 0.70 g/(usually around 0.4 g /), specific gravity 1.26 1.31. Color temperature: 180-200℃,carbonizationtemperature: 280-300 ℃. Methoxy value 19.0% one 30.0%, hydroxypropyl value 4% ~ 12%. Viscosity (22 ℃, 2%), 5 ~ 200000 mpa, s. Gel temperature (0.2%), a 50 to 90 ℃. HPMC with thickening ability, salt, PH stability, water retention, dimensional stability, excellent film-forming and extensive and enzymatic dispersion and bonding resistance, etc.
4 chemical properties
1, appearance: white or kind of white powder.
2, granularity; 100 mesh passing rate is more than 98.5%; 80 mesh pass rate of 100%. Special specifications of the particle size of 40 ~ 60 mesh.
3, carbonization temperature: 280-300 ℃Hydroxypropyl methyl cellulose
4, apparent density: 0.25 to 0.70 g/cm (usually in 0.5 g/cm), the proportion of 1.26 to 1.31.
5, color temperature: 190-200 ℃
6, surface tension, 2% aqueous solution for 42-56 dyn/cm.
7, dissolve performance: soluble in water and some solvents, such as the right proportion of ethanol/water, propyl alcohol/water, etc. Aqueous solution with surface activity. High transparency, stable performance, different specifications of the products different gel temperature and solubility with viscosity change, lower viscosity, the greater the solubility, different specifications HPMC its performance has a certain difference, HPMC dissolved in the water is not affected by pH.
8, HPMC increased with methoxy content reduce, the gel point, water solubility, surface activity also declined.
9, HPMC is thickening ability, salt resistance and low ash powder, pH stability, water retention, size stability, excellent film-forming, as well as a wide range of enzyme resistance, dispersion and caking property, etc.Five synthesis methods
1. The refined cotton cellulose treated with alkali liquor in the 35-40 ℃ and a half hours, crushing, smash cellulose, in 35 ℃ suitable for aging, make the base fiber average degree of polymerization in the required range. Will be put into etherification kettle, alkali fiber in turn add epoxy propane and methylchloride and 50-80 ℃ in etherification 5 h, the highest pressure 1.8 MPa. Then in 90 ℃ hot water adding suitable amount of hydrochloric acid and oxalic acid washing materials, volume expansion. Centrifuge dehydration. Washing to neutral, when the material in water content below 60%, at 130 ℃ hot air flow drying to contain less than 5%. Finally shattered 20 mesh products.
6 dissolved method
1. All types of dry mixing method can be used to join in the material;
2. Need to directly added to the aqueous solution at room temperature, had better use cold water dispersible, after joining in 10-90 minutes to thickening;
3. Common model after mixing dispersion with hot water first, stir in the cold water dissolved after cooling;
4. Such as happened when dissolved agglomeration phenomenon, because of inadequate stirring or reasons of the common type directly into the cold water, when a quick stir.
5. If the bubble when dissolved, can let stand for 2-12 hours (specific time determined by the solution consistency) or vacuum, pressure and other methods to remove, can also add the right amount of defoaming agent.The determination method of 7Method name: hydroxypropyl methyl cellulose - determination of the hydroxypropyl - hydroxypropyl oxygen measurement Application: apply to the measurement methods using hydroxypropyl oxygen radicals determination of hydroxypropyl methyl cellulose content of hydroxypropyl oxygen radicals in.This method is suitable for the hydroxypropyl methyl cellulose.Method principle: test samples according to hydroxypropyl oxygen measurement, calculation of the hydroxypropyl the content.Reagents: 1. 30% chromium trioxide solution (g/g)
2. Liquid sodium hydroxide titration (0.02 mol/L)
3. The fluid of phenolphthalein indicator
4. Sodium bicarbonate
5. Dilute sulphuric acid Potassium iodide 6.
7. Sodium thiosulfate standard solution (0.02 mol/L)
8. Starch indicating liquid
Instruments and equipment:
Sample preparation: 1. Liquid sodium hydroxide titration (0.02 mol/L)Preparation: clarify the sodium hydroxide saturated solution of 5.6 mL, add new boil over into 1000 mL of cold water.Calibration: take the 105 ℃ drying to constant weight benchmark about 6 g, potassium hydrogen phthalate precision said, boiling over 50 ml of cold water, add a new vibration wave, make it dissolved as far as possible; With phenolphthalein indicator liquid 2 drops, with the droplets, in the end, should make potassium hydrogen phthalate completely dissolved, titration solution to pink. Each 1 ml naoh standard solution (1 mol/L) is equivalent to 20.42 mg of potassium hydrogen phthalate. According to the consumption of the liquid and the extraction of potassium hydrogen phthalate dosage, calculate the concentration of the liquid. 5 times dilution that concentration into 0.02 mol/L.Storage: polyethylene plastic bottle, sealed; From two of the plug hole, hole 1, each inserted into the glass tube 1 pipe lime and sodium is linked together, 1 tube for suck out the liquid.2. The fluid of phenolphthalein indicatorTake 1 g phenolphthalein, add 100 ml of ethanol to dissolve3. Sodium thiosulfate standard solution (0.02 mol/L)Preparation: sodium thiosulfate 26 g and 0.20 g anhydrous sodium carbonate, add new boiling water right amount of dissolved into 1000 ml, shake well, place a month after filtration.Calibration: take the 120 ℃ drying constant weight benchmark is about 0.15 g, potassium dichromate precision said, iodine in a bottle and 50 ml of water dissolving, 2.0 g, potassium iodide and vibration wave gently dissolve, add 40 ml dilute sulphuric acid, shake well, dense; In the dark place after 10 minutes, add water, 250 ml diluted, with the droplets to nearly the end of added starch indicating liquid 3 ml, continue titration to disappear blue and light green, and the result of the titration correction by blank test. Each 1 ml sodium thiosulfate (0.1 mol/L) is equivalent to 4.903 g of potassium dichromate. According to the consumption of the liquid and the extraction of potassium dichromate dosage, calculate the liquid concentration, quick. 5 times dilution that concentration into 0.02 mol/L.Room temperature above 25 ℃, reaction liquid and dilution water should be cooled to about 20 ℃.
