Coating common sense: in the production process of water-based coating, there are flocculation lumps, how to solve?

Core tip: Recently, the company reaction, last week produced a batch of water-based coating The formula did not start After production, there are lumps and floccules in the coating, which are difficult to be removed by filtration, and the quality of waterborne coating is reduced What is the cause? What can be removed? Interpretation: There are several reasons for the appearance of floccules in the coating production process: 1 The most common is that after the dispersion of pigments and fillers, flocculent lumps appear when film-forming additives are added in the paint mixing process In this case, the agglomerates are not treated and forced to disperse and thicken, and the flocculated agglomerates remain in the coating, Paint knowledge how about Akzo Nobel Powder Coating Recommended introduction: powder coating is a kind of coating with different form from general coating, which is in powder form It is a new type of coating, because of its own advantages and more and more known by people Let's introduce Akzo Nobel Powder coating Akzo Nobel Powder coating is a cost-effective coating solution, which can be applied to different kinds of products After the treatment of static electricity and fire baking, a tough and durable coating surface will be formed, with the least impact on the environment Since the introduction of this technology, powder coating has been able to continue to maintain the Paint Home News: Recently, a company reaction, last week produced a batch of water-based paint The formula did not start After production, there are lumps and floccules in the coating, which are difficult to be removed by filtration, and the quality of waterborne coating is reduced What is the cause? What can be removed? Explanation: there are several reasons for floccules in paint production: 1 The most common reason is that the pigments and fillers are dispersed and floccules appear when film-forming aids are added in paint mixing process The flocculated agglomerates remained in the coating and were difficult to be removed by filtration 2 In the thickening process of coating production, the thickener concentration is high and the addition of thickener is too fast, which causes local severe thickening and becomes particle agglomerates In particular, the direct addition of alkali swelling thickener and cellulose ether thickener is easy to cause agglomerates 3 When cellulose ether thickener is used together with some whitening agents, such as hydroxyethyl cellulose (HEC) and whitening agent, flocculent lumps will appear, which will cause difficulty in filtration Solution: the flocculant of pigments and fillers caused by film-forming assistant often occurs in the system of low PVC (volume concentration of pigment) gloss coating The low PVC coating system is often matched with the dispersant of hydrophobic and low ion concentration Because PVC is low and the amount of polymer emulsion is high, the amount of film forming auxiliaries is large In the process of adding film forming AIDS, solvents disperse the dispersant from pigment and filler surface, so that pigments and fillers are flocculated In order to avoid this kind of flocculation, we can pre emulsify the film-forming assistant before adding it The pre emulsification composition of film forming aid can refer to the following ratio: film forming aid and about 5% cosolvent (glycol or propylene glycol, etc.), about 0.5% high HLB value wetting agent, 50% - 80% water, 100% in total, and evenly added after mixing For the dispersions that have caused flocculation, properly add wetting agent and disperse at high speed, open the flocs, and then paint normally General wetting agent accounts for about 0.2% of the total paint As for the flocculated agglomerates caused by too fast and too thick thickening agent, the way of adding can be changed to prevent them For high molecular weight cellulose ether, alkali swelling (ASE) or hydrophobically modified alkali swelling (HASE) thickeners, a certain concentration of pre gel can be made first, and can be added at any stage in the form of pre gel Cellulose ether thickener can also be added in the process of dispersing pigments and fillers in advance, so that the thickener can be fully dissolved in the paint Alkali swelling (ASE) and hydrophobic modified alkali swelling (hase) thickeners can be released with water, and added in the proportion of 4:1 water and thickener Polyurethane or polyether Association thickener can be used as cosolvent The cosolvent in the formula (glycol or propylene glycol, film forming assistant, etc.) can be diluted in the proportion of 1:1, and then added slowly under stirring Home of coatings is specialized in coatings, diatom mud, paint coating, coating technology, fire retardant coating news and coating, diatom mud, paint coating, coating technology, fire retardant coating decoration knowledge and decoration renderings,