Options for latex paint film additives.

resulting in a growing number of water-based systems due to the increased regulatory restrictions on volatile organic matter from coatings. Many research and development of water-based coatings made from emulsions for furniture, kitchen facilities, plastics, maintenance and other industrial applications. All of these use film-forming additives to promote membrane formation. At construction temperatures, they reduce the rigid module of the polymer, giving viscous flow and melting emulsion particles.in a sense, film-forming additives are temporary plasticizers that soften emulsion particles to form membranes and then evaporate from them. Some of the materials already used for this purpose are included in table 1.several factors must be taken into account when selecting the appropriate film-forming additives. One factor is the volatility rate. Coagulation emulsion film-forming materials can be obtained in a large volatile rate range, from volatile fast alcohol ethers to volatile very slow solvents such as Textanol esterol (2,2,4-trimethyl 11,3 diolyceride monoodes) and glycol butyl ether acetate, and others listed in Table 2.select a film-forming additive for a particular application, and the volatility rate of latex paint water should also be considered.at low humidity levels, ethyl acetate is 1 and water is volatile at a rate of 0.3. However, the effective volatility rate of water changes with humidity, at 65% relative humidity, the rate of water volatility is about 0.06. As humidity increases, the effective volatility rate of water continues to decrease until it is close to zero at 100% relative humidity.
the evaporation rate of membrane-forming additives needs to be slower than that of water in the system. And the relative humidity of the air has no effect. When latex paint is controlled for construction under low humidity conditions, a fast-volatile film-forming aid is applied (Table 3).. In these systems, glycol butyl ether (EB) is used as the most widely used film-forming aid. Others are also used, including ethylene glycol propylene ether (EP), propylene glycol propylene ether (PP) and propylene glycol butyl ether (PB).
EB should be used as a film-forming additive for industrial coatings for several reasons.in a typical industrial application, EB and other volatile fast film-forming additives are compared. EB has a greater expansion effect on emulsion particles, indicating a faster increase in viscosity, as in Table 4. PB has some expansion efficiency, ether class shows very little expansion efficiency. Ethyl methyl ethers reduce the viscosity of the emulsion.. EB also showed a slight reduction in the minimum film-forming temperature (MFT) of the emulsion (Table 5). In this experiment, MFT with a lotion of 50oF requires fewer EBTs.. In both emulsion membranes, EB is hardened faster than PB (Table 6). When the humidity is above 65 % of the construction, EB can not be very good film, in these high humidity, water volatility is slower than EB. Sufficient concentration is required to form a good membrane. Under these conditions, the EB evaporates before water, so there is no sufficient concentration required to form a good membrane.this occurs, a slower-volatile film-forming aid must be used. In some constructions, a mixture of volatile fast and slow film-forming additives is used to obtain good film-forming capacity and fast membrane hardening rate.factor to consider when selecting a film-forming additive is its activity, which is influenced by dissolved parameters and the tendency to distribute in the emulsion system.in different kinds of materials, there is a wide range of dissolving parameters that can be used as film-forming additives (Table 7) (the values used here refer to Hansen's total dissolving parameters).. Depending on the film-forming activity of different types of solvents, hansen dissolution parameters that are best for most emulsion polymers appear to be 8.5 to 11.5. Fatty family hydrocarbon solvents (range 7 to 8) as film-forming additives have no effect. Aromatic hydrocarbons and monoester solvents in the range of 8 to 9, in the emulsion system is some film-forming activity. The solubility parameters 9-11 of alcohol ether, alcohol ether esters, diesters and ester alcohols have an effect on emulsion film. The solubility parameters of binary alcohols with low molecular weight are 12-14, and there is no membrane additive.determines the manner in which the activity of membrane additives is distributed in emulsions, is probably the most important factor. The emulsion system consists of polymer and water. As a membrane additive is added to a emulsion system, it is distributed in these two phases, and the concentration of membrane additives in each phase is determined by the affinity and hydrotherapic balance of the polymer and the membrane rib agent. Very water-repugnent materials are strongly distributed to the polymer phase and are rarely present in the water phase;table 8 indicates that the distribution of membrane additives is based on data from tests on three emulsions. . Toxanol alcohol esters are highly water-repugnant and are strongly distributed in three emulsions to the polymer phase. The tendency to choose a species to move to the polymer phase is one of the basic reasons for the ester alcohol as an effective film-forming additive. Glycol butyl ether (DB) is very hydro-hydrophobic and is distributed almost between polymers and water phases. DB's dissolving parameters indicate that it should be an efficient film-forming aid, but the high percentage of the material is distributed in the water phase of the emulsion system, reducing its effectiveness. is important to consider the stability of the material when selecting film-forming additives (Table 9). The film-forming additives available have a wide range of erratic groups and are unstable for most in the milk system. But. In PH-high systems, the ester base of the membrane aid is hydrolysis unless protected by a structure in the molecule. table 10 represents the results of three different film-forming additives in latex emulsion aging tests. The emulsion contains a wide range of ester alcohols that are structurally protected by the ester chain, indicating no significant change in PH in aging. The emulsion contains DBE and DB acetate without protective esters, and PH showed a significant change during aging tests. . FOR PH low latex paint, DB acetate is widely used as a film-forming additive, but is not recommended for PH high latex paint due to poor stability of the ester base.
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