1. Product name:
01. Chemical name: hydroxypropyl methylcellulose
02. Full name in English: Hydroxypropyl Methyl Cellulose
03. English abbreviation: HPMC
2. Physical and chemical properties:
01. Appearance: white or off-white powder.
02. Particle size; the pass rate of 100 mesh is greater than 98.5%; the pass rate of 80 mesh is greater than 100%.
03. Carbonization temperature: 280～300℃
04. Apparent density: 0.25～0.70/cm3 (usually around 0.5g/cm3), specific gravity 1.26-1.31.
05. Discoloration temperature: 190～200℃
06. Surface tension: 2% aqueous solution is 42～56dyn/cm.
07. Soluble in water and some solvents, such as ethanol/water, propanol/water, trichloroethane, etc. in appropriate proportions.
Aqueous solutions are surface active. High transparency, stable performance, gel temperature of products with different specifications
Different, the solubility changes with the viscosity, the lower the viscosity, the greater the solubility, the performance of different specifications of hydroxypropyl methylcellulose (HPMC) has certain differences, the dissolution of hydroxypropyl methylcellulose (HPMC) in water is not affected PH value effect.
08. With the decrease of methoxyl content, the gel point increases, the water solubility decreases, and the surface activity of hydroxypropyl methylcellulose (HPMC) also decreases.
09. Hydroxypropyl methylcellulose (HPMC) also has thickening ability, salt resistance, low ash powder, PH stability, water retention, dimensional stability, excellent film-forming property, and wide range of enzyme resistance, dispersion characteristics such as sex and adhesiveness
Three, hydroxypropyl methylcellulose (HPMC) characteristics:
The product combines many physical and chemical properties to become a unique product with multiple uses, and the various properties are as follows:
(1) Water retention: It can hold water on porous surfaces such as wall cement boards and bricks.
(2) Film formation: It can form a transparent, tough and soft film with excellent oil resistance.
(3) Organic solubility: The product is soluble in some organic solvents, such as ethanol/water, propanol/water, dichloroethane, and a solvent system composed of two organic solvents.
(4) Thermal gelation: When the aqueous solution of the product is heated, it will form a gel, and the formed gel will become a solution again after cooling.
(5) Surface activity: Provide surface activity in the solution to achieve the required emulsification and protective colloid, as well as phase stabilization.
(6) Suspension: It can prevent the precipitation of solid particles, thus inhibiting the formation of sediment.
(7) Protective colloid: it can prevent droplets and particles from coalescing or coagulating.
(8) Adhesiveness: Used as an adhesive for pigments, tobacco products, and paper products, it has excellent performance.
(9) Water solubility: The product can be dissolved in water in different quantities, and its maximum concentration is only limited by viscosity.
(10) Non-ionic inertness: The product is a non-ionic cellulose ether, which does not combine with metal salts or other ions to form insoluble precipitates.
(11) Acid-base stability: suitable for use within the range of PH3.0-11.0.
(12) Tasteless and odorless, not affected by metabolism; used as food and drug additives, they will not be metabolized in food and will not provide calories.
4. Hydroxypropyl methylcellulose (HPMC) dissolution method:
When hydroxypropyl methylcellulose (HPMC) products are directly added to water, they will coagulate and then dissolve, but this dissolution is very slow and difficult. There are three suggested dissolution methods below, and users can choose the most convenient method according to their usage:
1. Hot water method: Since hydroxypropyl methylcellulose (HPMC) does not dissolve in hot water, the initial stage of hydroxypropyl methylcellulose (HPMC) can be evenly dispersed in hot water, and then when it is cooled, three A typical method is described as follows:
1). Put the required amount of hot water into the container and heat it to about 70°C. Gradually add hydroxypropyl methylcellulose (HPMC) under slow stirring, the hydroxypropyl methylcellulose (HPMC) starts to float on the surface of the water, and then gradually forms a slurry, cool the slurry under stirring .
2). Heat 1/3 or 2/3 (required amount) of water in the container and heat it to 70°C. According to the method of 1), disperse hydroxypropyl methylcellulose (HPMC) to prepare hot water slurry Then add the remaining amount of cold water or ice water in the container, then add the above-mentioned hydroxypropyl methylcellulose (HPMC) hot water slurry to the cold water, and stir, and then cool the mixture.
3). Add 1/3 or 2/3 of the required amount of water into the container and heat it to 70°C. According to the method of 1), disperse hydroxypropyl methylcellulose (HPMC) to prepare hot water slurry; The remaining amount of cold or ice water is then added to the hot water slurry and the mixture is cooled after stirring.
2. Powder mixing method: hydroxypropyl methylcellulose (HPMC) powder particles and an equal or greater amount of other powdery ingredients are fully dispersed by dry mixing, and then dissolved in water, then the hydroxypropyl methylcellulose Base cellulose (HPMC) can be dissolved without agglomeration. 3. Organic solvent wetting method: pre-disperse or wet hydroxypropyl methylcellulose (HPMC) with organic solvents such as ethanol, ethylene glycol or oil, and then dissolve it in water. At this time, hydroxypropyl methylcellulose ( HPMC) can also be dissolved smoothly.
5. Main uses of hydroxypropyl methylcellulose (HPMC):
Hydroxypropyl methylcellulose (HPMC) can be used as a thickener, dispersant, emulsifier and film-forming agent. Its industrial-grade products can be used in daily chemicals, electronics, synthetic resins, construction and coatings.
1. Suspension polymerization:
In the production of synthetic resins such as polyvinyl chloride (PVC), polyvinylidene chloride and other copolymers, suspension polymerization is most commonly used and is necessary to stabilize the suspension of hydrophobic monomers in water. As a water-soluble polymer, hydroxypropyl methylcellulose (HPMC) products have excellent surface activity and act as a colloidal protective agent, which can effectively prevent the aggregation of polymer particles. Furthermore, although hydroxypropylmethylcellulose (HPMC) is a water-soluble polymer, it is also slightly soluble in hydrophobic monomers and increases the porosity of the monomers from which the polymeric particles are produced, so that it can Provides polymers with excellent ability to remove residual monomers and enhance absorption of plasticizers.
2. In the formulation of building materials, hydroxypropyl methylcellulose (HPMC) can be used for:
1). Adhesive and caulking agent for gypsum-based adhesive tape;
2). Bonding of cement-based bricks, tiles and foundations;
3). Plasterboard-based stucco;
4). Cement-based structural plaster;
5). In the formula of paint and paint remover.
Post time: May-24-2023