Contact Us

Shenyang Hualun Lubricant Additive Co.,Ltd

ADD: Room 8, Floor 25,Block A, No.1 Jianshezhong Road, Tiexi District, Shenyang, Liaoning, China

Contacts: Sylvia yu

Tel: 86-24-85611296  

Mobile: 86-15004099845

Fax: 86-24-85611282


Home > News > Content
Detergent Dispersant Improve The Dispersion Stability Of The Dye Jul 04, 2017

As the solubility of disperse dyes is very small, the application of the Detergent Dispersant mainly by the dye particles dispersed in water, made of dispersion or suspension.

The hydrophilicity of the disperse dyes is extremely small, and the dyes of the dyes in the water have a large hydrophobicity. Due to the exclusion of water, these uncharged dye particles will naturally move closer to each other, due to small particles gradually become large particles, resulting in the so-called "crystal growth" or "cohesion" phenomenon. So that the dye in the water to lose stability, and lead to dyeing performance (dyeing rate, balanced dyeing percentage, leveling, color vividness, dyeing fastness) serious changes.

In the presence of a Detergent Dispersant:

(1) Dye Production The newly formed hydrophobic dye crystal surface or the hydrophobic dye particles in the dyeing process will be adsorbed with the hydrophobic part of the Detergent Dispersant to form the dye particles of the hydrophilic base toward the water. So that the dye particles from the original hydrophobicity into hydrophilic, from water exclusion, improve the dispersion stability of the dye.

(2) Since the surface of the dye particles formed by the dye and the Detergent Dispersant is covered with a negative charge, there is a repulsive force between the dyestuffs. Due to the role of charge repulsion, the dye grains collide with each other and the probability of aggregation is greatly reduced, and thus improve the dispersion stability of the dye.

(3) Since water is a polar molecule, the hydrophilic moiety of the Detergent Dispersant coated on the surface of the dye grain also absorbs a large amount of water molecules through the ions to form a direct or indirect hydration layer. Dye grain in the charge repulsion and hydration of the double protection, the grain is more difficult to grow, it is difficult to gather. As a result, the dispersion stability of the dye solution is further improved. In addition, it will increase the solubility of the dye (or solubilization), improve the dyeing rate and the balance of dyeing percentage.

First, the role of Detergent Dispersants in the coating

The vast majority of the pigments used in the coating are in the form of agglomerates and agglomerates of primary particles. If these pigment particles of different sizes can not be dispersed into finer particles or primary particles and make them no longer Aggregation or flocculation of the stable dispersion system, will produce flocculation, back coarse, precipitation, floating color flowers, reduced gloss, coloring and hiding power drop defects.

Detergent Dispersant is an interfacial active substance capable of improving the stability of the pigment dispersion. The Detergent Dispersant added to the liquid medium can adsorb the adsorbent layer on the surface of the pigment which is pulverized into fine particles to produce charge repulsion and steric hindrance to prevent the dispersed Pigment particles again create a harmful flocculation, can maintain the dispersion in a stable state of suspension.

Second, the classification of Detergent Dispersants

Pigment dispersion process is more complex, but there are three roles is the most important, that is, wetting effect, the role of aggregation and stabilization, only when the wetting, desorption and stabilization of the three synergies, the pigment can be uniform and stable To disperse in the paint. The use of a suitable wetting and dispersing agent can provide both the effect of pigment wetting, desorption and stabilization, not only to shorten the time of grinding and dispersing, to reduce the viscosity of the grinding system, to improve the coloring and hiding power of the pigment, Flocculation, back to coarse, precipitation, improve paint storage stability, to ensure that the pigment is always in a good dispersion, to maintain the uniformity of color. Most of the pigment Detergent Dispersant has both a wetting function and a decentralized stabilizing effect.

Commonly used Detergent Dispersant chemical structure are:

① low molecular weight carboxylic acid amide salt and electric long chain carboxylic acid polyamino salt, with more adsorbent, can form a solid adsorption layer on the pigment surface to improve the stability of the pigment dispersion, play to prevent the floating color Flower effect;

② high molecular weight carboxylic acid ester polymer, through the polymer chain with a group of molecules adsorbed on the surface of the pigment to form a steric hindrance control to prevent the flocculation of pigments to maintain the stability of the pigment dispersion system;

(3) A polymer or block copolymer containing an anchored group, the anchor group can be firmly fixed to the surface of the pigment, and the higher molecular weight solvate chain can be effectively dispersed in the paint to increase the thickness of the adsorbent layer, Improve dispersion stability;

④ polycarboxylic acid polymer, containing more carboxyl, the polarity is very strong, can make the formation of thixotropic fluid paint, so that the formation of controllable flocculation of pigment flocculation state, to prevent floating color flowers is very effective.

Third, the role of Detergent Dispersant mechanism

The inorganic pigment surface has a higher polarity, so that the low molecular weight pigment Detergent Dispersant is more easily adsorbed and can be adsorbed on the pigment surface more permanently; and the organic pigment surface is substantially polar, so that the low molecular weight pigment Detergent Dispersant is difficult to sustain , A higher molecular weight Detergent Dispersant or a polymeric Detergent Dispersant containing an anchoring group is required. The adsorption of the high molecular weight Detergent Dispersant on the surface of the pigment is adsorbed on the surface of the pigment particles through the functional group and the polymer anchor chain. At the same time, the adsorption morphology and pigment surface characteristics, morphology, charge distribution, the structure of polymer compounds, composition, nature, the type of solvent in the dispersion medium, the solubility of polymer polymers and many other aspects. A polymeric Detergent Dispersant is a specially designed compound for the purpose of dispersion required for the nature of the pigment.

Compared with the small molecule Detergent Dispersant of the single anchoring group, the polymer Detergent Dispersant contains multiple anchoring points, which can be adsorbed on the surface of the dispersed particles more effectively. In general, the homopolymer is not a good Detergent Dispersant, because it is a better solvation chain or a good anchoring group, and good repulsive force stabilization needs both, to meet this requirement A copolymer, such as a polymer as an aqueous pigment Detergent Dispersant, is usually a random copolymer, a graft copolymer or a block copolymer.