1. Different traits
Hydroxypropyl methylcellulose: white or off-white fibrous or granular powder, belonging to a variety of non-ionic cellulose mixed ethers. It is a semi-synthetic, inactive, viscoelastic polymer.
Hydroxyethyl cellulose: (HEC) is a white or light yellow, odorless, non-toxic fibrous or powdered solid, prepared by etherification of alkaline cellulose and ethylene oxide (or chloroethanol). It belongs to non-ionic soluble cellulose ethers.
2. Different uses
Hydroxypropyl methylcellulose: Used as a thickener, dispersant and stabilizer in the coating industry, and has good compatibility in water or organic solvents. As a paint remover; as a dispersant in the production of polyvinyl chloride, it is the main auxiliary agent for the preparation of PVC by suspension polymerization; it is also widely used in the leather, paper products, fruit and vegetable preservation and textile industries.
Hydroxyethyl cellulose: used as an adhesive, surfactant, colloidal protective agent, dispersant, emulsifier and dispersion stabilizer, etc. It has a wide range of applications in coatings, inks, fibers, dyeing, papermaking, cosmetics, pesticides, mineral processing, oil extraction and medicine.
3. Different solubility
Hydroxypropyl methylcellulose: It is almost insoluble in absolute ethanol, ether, and acetone; it swells into a clear or slightly turbid colloidal solution in cold water.
Hydroxyethyl cellulose: has the properties of thickening, suspending, bonding, emulsifying, dispersing, and retaining moisture. Solutions with different viscosity ranges can be prepared. It has exceptionally good salt solubility to electrolytes.
Hydroxypropyl methylcellulose (HPMC) Physical and chemical properties:
1. Appearance: MC is white or almost white fibrous or granular powder, odorless.
2. Properties: MC is almost insoluble in absolute ethanol, ether and acetone. It disperses and swells rapidly in hot water at 80~90℃, and dissolves quickly after cooling. The aqueous solution is quite stable at room temperature and can gel at high temperature, and the gel can change with the solution with the temperature. It has excellent wettability, dispersibility, adhesion, thickening, emulsification, water retention and film-forming properties, as well as impermeability to grease. The formed film has excellent toughness, flexibility and transparency. Because it is non-ionic, it can be compatible with other emulsifiers, but it is easy to salt out and the solution is stable in the range of PH2-12.
3. Apparent density: 0.30-0.70g/cm3, density is about 1.3g/cm3.
2. Dissolution method:
The MC product is directly added to the water, it will agglomerate and then dissolve, but this dissolution is very slow and difficult.The following three dissolution methods are suggested, and the user can choose the most convenient method according to the use situation:
1. Hot water method: Since MC does not dissolve in hot water, MC can be evenly dispersed in hot water at the initial stage. When it is subsequently cooled, two typical methods are described as follows:
1). Put the required amount of hot water in the container and heat it to about 70°C. Gradually add MC under slow agitation, start to float on the surface of the water, and then gradually form a slurry, and cool the slurry under agitation.
2). Add 1/3 or 2/3 of the required amount of water into the container and heat it to 70℃. Follow the method of 1) to disperse MC to prepare hot water slurry; then add the remaining amount of cold water or ice water Into the hot water slurry, cool the mixture after stirring.
2. Powder mixing method: Mix MC powder particles with an equal or larger amount of other powdery ingredients to fully disperse them by dry mixing, and then add water to dissolve, then MC can be dissolved without agglomerating.
3. Organic solvent wetting method: pre-disperse or moisten MC with an organic solvent, such as ethanol, ethylene glycol or oil, and then add water to dissolve, then MC can also be dissolved smoothly at this time.
3. Purpose:
This product is widely used in building construction, building materials, dispersive coatings, wallpaper pastes, polymerization additives, paint removers, leather, ink, paper, etc. as thickeners, adhesives, water-retaining agents, film-forming agents, Excipients, etc. For example, it is used as a binder, thickener and water-retaining agent in building materials, as a film-forming agent and thickener in the coating industry, and it is also widely used in fields such as petroleum drilling and daily chemical industry.
The physical and chemical properties of methyl cellulose (MC):
3. Appearance: MC is white or almost white fibrous or granular powder, odorless.
Properties: MC is almost insoluble in absolute ethanol, ether and acetone. It disperses and swells rapidly in hot water of 80~90>℃, and dissolves quickly after cooling. The aqueous solution is quite stable at normal temperature and can gel at high temperature, and the gel can change with the solution with the temperature. It has excellent wettability, dispersibility, adhesion, thickening, emulsification, water retention and film-forming properties, as well as impermeability to grease. The formed film has excellent toughness, flexibility and transparency. Because it is non-ionic, it can be compatible with other emulsifiers, but it is easy to salt out and the solution is stable in the range of PH2-12.
1.Apparent density: 0.30-0.70g/cm3, density is about 1.3g/cm3.
Forth. Dissolution method:
MC> The product is directly added to water, it will agglomerate and then dissolve, but this dissolution is very slow and difficult. The following three dissolution methods are suggested, and users can choose the most convenient method according to the usage conditions:
1. Hot water method: Since MC does not dissolve in hot water, MC can be evenly dispersed in hot water at the initial stage. When it is subsequently cooled, two typical methods are described as follows:
1). Put the required amount of hot water in the container and heat it to about 70°C. Gradually add MC under slow agitation, start to float on the surface of the water, and then gradually form a slurry, and cool the slurry under agitation.
2). Add 1/3 or 2/3 of the required amount of water into the container and heat it to 70°C. Follow the method in 1) to disperse MC to prepare a hot water slurry; then add the remaining amount of cold water or ice water Into the hot water slurry, cool the mixture after stirring.
Powder mixing method: dry mixing MC powder particles with equal or larger amounts of other powdered ingredients to fully disperse them, and then add water to dissolve them, then MC can be dissolved without agglomeration.
3. Organic solvent wetting method: disperse or moisten MC with an organic solvent, such as ethanol, ethylene glycol or oil, and then add water to dissolve it. Then MC can also be dissolved smoothly.
Five. Purpose:
This product is widely used in building construction, building materials, dispersive coatings, wallpaper pastes, polymerization additives, paint removers, leather, ink, paper, etc. as thickeners, adhesives, water-retaining agents, film-forming agents, Excipients, etc. For example, it is used as a binder, thickener and water-retaining agent in building materials, as a film-forming agent and thickener in the coating industry, and it is also widely used in fields such as petroleum drilling and daily chemical industry.
1. Construction industry: As a water-retaining agent and retarder of cement mortar, it makes the mortar pumpable. Used as a binder in plaster, plaster, putty powder or other building materials to improve spreadability and prolong operation time. It can be used to paste ceramic tiles, marble, plastic decoration, paste enhancer, and can also reduce the amount of cement. The water retention properties of HPMC prevent the slurry from cracking due to drying too fast after application, and enhance the strength after hardening.
2. Ceramic manufacturing industry: widely used as a binder in the manufacturing of ceramic products.
3. Paint industry: As a thickener, dispersant and stabilizer in the paint industry, it has good compatibility in water or organic solvents. As a paint remover.
4. Ink printing: As a thickener, dispersant and stabilizer in the ink industry, it has good compatibility in water or organic solvents.
5. Plastics: used as mold release agents, softeners, lubricants, etc.
6. Polyvinyl chloride: It is used as a dispersant in the production of polyvinyl chloride and is the main auxiliary agent for the preparation of PVC by suspension polymerization.
7. Others: This product is also widely used in leather, paper products, fruit and vegetable preservation and textile industries.
8. Pharmaceutical industry: coating materials; film materials; rate-controlling polymer materials for slow-release preparations; stabilizers; suspending agents; tablet binders; thickeners. Health hazards: this product is safe and non-toxic, and can be used as a food additive , No heat, no irritation to skin and mucous membrane contact. Generally considered to be safe (FDA1985), the allowable daily intake is 25mg/kg (FAO/WHO 1985), and protective equipment should be worn during operation.
Environmental impact: Avoid random throwing to cause air pollution by flying dust.
Physical and chemical hazards: Avoid contact with fire sources, and avoid the formation of a large amount of dust in a closed environment to prevent explosive hazards.
This thing is actually only used as a thickener, which is not good for the skin.