DISPERSING AGENT FOR PRINTING INKS

DISPERSING AGENT FOR PRINTING INKS - Names and Identifiers

Name	DISPERSING AGENTS
Synonyms	MF DISPERSANT MF DISPERSING AGENTS Grinding Dispersant DISPERSING AGENT FOR PRINTING INKS

DISPERSING AGENT FOR PRINTING INKS - Physico-chemical Properties

Use	Applications for paper, coatings and other industries in a variety of pigment and filler dispersion, can also be applied to mixed pigments

DISPERSING AGENT FOR PRINTING INKS - Uses and synthesis methods

overview

Dispersant refers to a chemical that can inhibit the deposition of sludge, paint film, sludge and other substances, and can make these deposits suspended in oil in a colloidal state. The biggest difference between it and detergent is that it does not contain metal, so it is also called ashless dispersant. The development of dispersant is inseparable from the development of automobile industry. From the 1940s to the 1950s, the number of foreign cars increased, urban traffic jams, cars often ran at low speeds and stopped and opened, and the temperature of the crankcase oil was low, so that the generated water vapor could not be discharged, and the sludge and other substances formed emulsified oil sludge. This sludge seriously affects the normal use of crankcase oil. For this kind of sludge, the previously used metal detergents such as thiophosphonates, sulfonates, and phenates have almost no effect. Therefore, it is urgent to develop new additives that are effective for this sludge.

Types of dispersants

dispersants are generally divided into two categories: inorganic dispersants and organic dispersants. Commonly used inorganic dispersants include silicates (such as water glass) and alkali metal phosphates (such as sodium tripolyphosphate, sodium hexametaphosphate, sodium pyrophosphate, etc.). Organic dispersants include triethylhexyl phosphoric acid, sodium dodecyl sulfate, methyl pentanol, cellulose derivatives, polyacrylamide, gurel gum, fatty acid polyethylene glycol ester and polyether, as well as organic silicone and silicone oil. In the beneficiation process, dispersant is a kind of adjuster used in match with collector, foaming agent or selective flocculant. The collector or flocculant can better interact with different minerals through dispersant to achieve the purpose of sorting. It is generally used to disperse the sludge and effectively separate the desired mineral from the gangue. For example, when selecting kaolin, in order to eliminate dyed impurity minerals such as quartz, iron and titanium, the dispersant sodium hexametaphosphate is added to make the kaolin in a highly suspended stable state, and then selective flocculant is added to make one of them. One mineral (kaolin or impurity ore) forms flocculent settlement, and the other is still fully dispersed, so as to realize sorting and improve the grade and natural whiteness of kaolin. In the flotation process of sulfide ore, an appropriate amount of water glass is used as a dispersant to disperse the gangue fine mud, so that the sulfide ore and the reagent can work better, emerge from the slurry, and improve the grade of the concentrate. The amount of dispersant should be moderate. Excessive dispersant will cause the loss of the material to be processed, or it will not have the effect of dispersing, but play an inhibitory effect. In addition to being used in mineral processing industry, dispersants are also widely used in light industry, food, chemical industry and other industries.

mechanism of action

The dispersant is an additive that can improve and improve the dispersion performance of the agent. In the processing of a variety of pesticide formulations, or due to the viscosity of the original drug itself, or due to the flocculation of the powder, or due to the excessive interfacial tension of the oil-water two phases, the original drug is difficult to disperse and cannot be processed into a well-dispersed stable preparation. In addition to the performance of processing machinery, good dispersion additives often play a decisive role, such as pulp waste liquid (high concentration aqueous solution of lignosulfonate) used in colloidal sulfur processing.

dispersants have two mechanisms of action :

① The original liquid non-water-soluble pesticide is difficult to disperse due to excessive surface tension, such as oils and organic solvents with weak polarity, which form an oil/water interface in water with great interfacial tension, so the oil/water is two layers. Although the oil can be dispersed into oil beads under strong mechanical stirring, after stopping stirring, it is quickly stratified under the action of interfacial tension. Sulfur melts at 114 ℃ and becomes liquid. For the same reason, it cannot be mixed with water. However, if a surface active substance is added to the oil/water system and the oil is dispersed by mechanical force, a monomolecular layer of surface active substance is immediately formed on the surface of the oil bead at this time, which surrounds the oil beads so that the oil beads cannot be condensed and merged, thus the generated oil beads can be stably dispersed in the water phase.

② There is also water/solid interfacial tension between solid powder and water medium. At the same time, the air film adsorbed on the surface of solid powder also hinders the affinity with water, which is beneficial to the flocculation of powder. Surface active substances can also repel the air film on the surface of the powder particles and reduce the water/solid interfacial tension, thus making the powder particles easy to disperse.

classification

Application areas The use of dye dispersants in the dyeing process can prevent the disperse dyes used for cellulose acetate from precipitating during dyeing. It can also be used as a leveler for dyeing cellulose fibers with urn dyes. It is also used for dyeing polyester fibers.

It is often used as a dispersant for aqua and granules in pesticides. The dispersant used for the water agent can be alkyl naphthalene sulfonate, alkyl benzene sulfonate, ethylene oxide alkyl phenyl ether; the dispersant used for the granule can be alkyl benzene sulfonate, polycarbonate, dioctyl sulfosalicylate, etc.

In terms of food, in order to prevent the juice from coagulating and precipitating, and to make the pigment and other additives more evenly dispersed in food, dispersants such as polyethylene glycol, microcrystalline cellulose and polysorbate are also used.

water-based dispersants used in the coating and ink industry, such as polyacrylate, copolymer of sodium maleate and olefin, polyethylene oxide group or aryl ether, and non-aqueous dispersants, such as sorbitol anhydric fatty acid ester, polyethylene oxide alkyl amine, alkyl diamine, etc.

Wetting Dispersant

The good dispersion of pigments into the binder is an important part of printing ink manufacturing technology. This includes evenly distributing the pigment in the ink and pulverizing it into fine particles. The dispersion of the pigment is related to the properties of the pigment itself, the resin used in the binder, the oil or the solvent and the interaction between them.

Last Update：2024-04-09 21:22:08