A brief analysis of the paint floating hair flower problem

The modulation of paint color is very complex in the process of paint production and construction often encounter floating color hair flower problem, paint floating color hair flower, color and standard plate produce color difference, color change becomes very difficult, both waste pigment and color adjustment is not allowed, at the same time the paint can opening effect is very poor, and paint dry after the construction coating film color deviation and difficult to apply uniform.
is one of the phenomena of dynamic separation of pigments: pigment separation obstacles occur in the horizontal direction, resulting in unearral color coating and hair flowering. Floating color is the color in the vertical direction of change, coatings in the film and drying process of one or more pigment separation, one pigment floating to the surface, the other pigment in sitant or sink to the bottom .
can you observe and judge the floating flower phenomenon in the laboratory?
Can start from two aspects:
can be static floating color:
paint scattered evenly after a period of time in the tank, one or more pigments in the tank separated surface phenomenon, such as storage for a period of time, after opening the tank to see the inside surface of the tank appear black, indistinct or white phenomenon.
coating film dynamic floating color:
coating film drying process pigment particle separation phenomenon is called dynamic floating color, dynamic floating pigment separation is divided into two cases: one is the film hair flower surface color is not equal, the other is the coating film floating color good surface color is the same, but the surface layer and the underlying color is different.
Kneading with your fingers to identify floating colors, first dumping or coating the paint on a glass plate or black-and-white paper jam, flattening the state, kneading your fingers until the coating begins to become viscous, pigment particles no longer migrate to separate, if the paint has floating color, the surface that has not been kneaded and the surface after kneading in the color There are differences in phase, the pigment in the kneading process is easy to separate and silky streaks appear, the surface of the coating film after drying will appear angular vortex pattern, refers to the degree of kneading color change with the conditions of the finger research, the length of kneading time or the weight of kneading action and coating film drying speed, etc. have a great impact on the degree of color change.
coating floating hair flower factors are many, pigment particle size difference, the surface pressure difference of the various substances in the system, as well as the hydromassive oil balance value (HLB), emulsion and color paste compatibility of the latex paint floating hair flower caused a greater impact, the following is discussed in detail.
1, the particle size of the pigment particles on the paint floating flower effect
the coating in the drying process, with the volatile part of the paint, these volatiles will also be clamped with a part of the pigment, fillers to bring them to the coating film, and these When pigment and filler particles are transported to the surface, finer particles with a higher surface area are easy to transport, while coarse particles with a relatively low surface area are hindering movement, and when latex paint coating film is dry, more hydro-hydro-like substances tend to evaporate quickly.
If the white slurry is more hydro-hydro-hydro than the color paste, i.e. the white pigment particles are more hydro-hydro-hydro-hydro than the pigment particles in the color paste, they are more likely to be brought to the surface by the volatile material of the strong polarity." Coupled with the pigment particle particle size difference is too large, so that the pigment, filler between the mixing capacity becomes very poor.
the above reasons, with this pigment made of color paint is not good construction, the construction process of the paint floating white phenomenon is serious, and the coating film is floating color. Floating white is difficult to adjust dark paint and can cause waste of pigments. The solution is to carefully select the pigment, filler, so that the particle size of the selected pigment to match;
2, the effect of poor surface pressure on paint floating hair flower
In the ordinary color palette, often found that some color paste in the white base paint is difficult to disperse evenly, scattered good color paint after a period of rest, soon there is a color or floating phenomenon occurred, or paint canning effect is not good.
In the process of painting, the production of white paste and the production process of the color slurry is different, the production of white pulp often uses anion-type dispersant or ion-type polylyte dispersant, while the color paste is mostly non-ion dispersant, or with part of the anion dispersant, so the white pigment and color pigment particles because of adsorption of a different layer of wetting dispersant and has different surface properties, its hydromassive oil value is not the same. The surface strength of the general ionized surfactant is greater than that of the non-ionized surfactant.
are non-ion surfactants, because the molecular structure of the hydrophobic end is not the same, its surface strength is not the same, and the outermost chain link of the molecular hydrophobic end structure contributes the most to the surface stress. Molecules with low surface energy mean less force between molecules and lower surface pressure. From the thermodynamics aspect, the material with low surface pressure is easy to absorb and transfer to the interface, and make the system stable, because the surface pressure reduction weakens the tendency of the liquid shrinking surface and droplets, reduces the additional pressure difference of the curved liquid surface, and thus is conducive to the stability of the liquid surface and dispersion system.
, if there is a large difference between the surface tone between the white slurry or the color paste and the surface tone difference of the system, the coating with this slurry configuration is more prone to floating color.
3, the solubility between the system
emulsion and color paste compatibility is good, paint and coating film floating hair flower situation will be much better, emulsion on the color paste wet good then color paint color display is also very good.
In water coatings often use anionic and non-ionized surfactants as wetting dispersants, inorge pigments with polarity and ionized surfaces in the water system, can act on the polar basis or ions of added ionized surfactants, forming a two-layer adsorption layer.
In the water pigment slurry pigment surface adsorption of surfactants, the formation of a protective layer, but the protective layer between the forces have inter-molecular force, static power, so the force between the force is not the same, when the above color paste and various types of lotion or latex paint mixed, the dispersion stability performance of the plasma is not the same, When the surface activity agent on the surface of pigment particles and the surface adsorption of emulsion particles, i.e. emulsion or water, the affinity between the pigment particles adsorption of surfactants is stripped, making the protective layer of pigment particle surface thin, resulting in pigment flocculation, which causes the paint coating film floating flowering.
Of course, when the emulsifier outside the emulsion particles and the pigment in the color paste, filler particles outside the surfactant compatibility is good, then the emulsion for these colors, filling particles wetting is good, the whole color paint color display is good, colorful, and not floating color.
4, the effect of hydro-friendly oil balance value on floating hair flowers
Hydro-hydro-oil balance value (HLB) is a very sensitive issue, in the production of coatings often use a variety of materials: emulsions, pigments, fillers, solvents, solvents and various additives.
These materials have their own hydromassive oil balance value (HLB value), each material hydromassive oil balance value matching the performance of the entire coating system is very good, floating color, flowering, water hydration and other phenomena will be overcome.
Of course, we use emulsions, pigments selected, hydromassive oil balance value is HLB value can not be changed, but you can carefully select additives, that is, wet dispersants, thickeners, etc. to adjust the HLB value of the entire system, so that the HLB value of the entire system balance.
We know that the pro-oil substance has a small surface pressure on its pro-oil end, the coating is stored in a container tank, these pro-oil substances can easily float to the surface, from a thermodynamic point of view, the whole system energy reduction, system stability. When the production of latex paint in static is floating color in the container, not only the effect of opening the can is not good, construction performance is not good, the film state is not good.
If the paint floating white, said to understand the slurry HLB value is relatively small, white pulp is more pro-oil, so, the production of white pulp to do a little hydroploring, if the paint floating is the color of the slurry, said to understand the slurry HLB value is relatively large, more hydro-hydro, in the production of white slurry to do some oil-friendly, to prevent paint floating color.
the hydro-hydromassive oil balance value (HLB value) can be done by carefully selecting wetting and dispersing agents. The ammonium salt dispersant with hydrophobic group in anion dispersant is more oil-owning than the sodium pyrate dispersant, the HLB value is small, and the ammonium salt dispersant with hydrophobic base group also has a great improvement on the floating color of latex paint coating film.
Because when the pigment particles wrap around this type of dispersant, the pigment particles around not only static resistance, there is also spatial resistance, and the coating film in the drying process, with the evaporation of water, ammonium salt is also volatile, so that such dispersion The agent is more hydrophobic, thus wrapping the pigment particles of such dispersants and film-forming material compatibility is better, coupled with spatial resistance makes the structure become very puffy, so that the coating film in the drying process film floating color, that is, the dynamic process of floating color is also suppressed.
5, thickener on latex paint floating hair flower effect
some fake plastic strong compound thickener and HLB value of the larger surfactant has a great affinity, so that it is dissociated on the pigment surface, resulting in pigment accumulation and flocculation, and thus make the system coloring force decreased and the production of floating hair flower. In the system of mixing organic and inorganic pigments, especially when titanium white is shared with blue, turquoise and carbon black slurry, a combination thickener with weak false plasticity can obtain latex paint with more satisfied color and good leveling.
thickeners or dispersants and other groups such as hydrophobic end base, pigment particles have a strong affinity, adsorption pigment particles form bridge flocculation lead to paint floating color, strong hydrophobic ligation thickener, such as due to hydrophobic group adsorption of color slurry particles, causing bridge Flocculation coloration is poor, alkali-soluble thickeners because of the amount of ion charge with different, thickening of salt in the coating film drying led to different charge quantities of film, strong polar pigment particle affinity is different, floating color severity, different systems in color display there are differences.