How to choose a defoamers for the formulation system correctly? What factors affect the defoaming efficiency? After learn the factors that affect the defoaming efficiency, let's take a look at the impact of our main protagonist today-"defoamer" on the coating system. So is the defoaming efficiency higher, the defoamer is better? Generally speaking, the better the antifoaming effect of the defoamer, the worse its compatibility with the system. Therefore, the best choice of defoamer is to achieve a balance of performance. There are many factors in the coating formulation that affect the air bubbles and defoaming, so the selection of defoaming agents should be considered comprehensively. Surface tension The surface tension of the paint has a greater impact on the defoamer. The surface tension of the defoamer must be lower than the surface tension of the paint, otherwise there will be no defoaming and foam suppression effect. The surface tension of the coating is a va...
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The impact of the COVID-19 on the global economy and how will paper industry going? Covid-19 is still in the stage of global spread As of the evening of May 2, according to relevant statistics of the International Health Organization, there have been more than 3.27 million cases of new coronary pneumonia diagnosed globally, including a total of 230,000 deaths. The United States currently has the most confirmed cases of infection, with a cumulative total of more than 1.06 million cases. The total cumulative cases in Europe are more than 1.49 million cases, of which Spain, Italy and the United Kingdom have cumulative cases of 210,000, 200,000 and 170,000 cases, the three countries with the largest number of infections in Europe. The number of newly confirmed cases per day in Spain and Italy has shown a slowing trend. Brazil is the country with the largest cumulative number of confirmed cases in Latin America, reaching 85,000 cases, exceeding the current cumulative number of confirmed...
Is silicone oil safe? From a physiological point of view, polysiloxane is one of the polymers with the lowest known activity. The results of toxicological studies suggest that dimethyl silicone oil, which removes low-boiling substances, is non-toxic and can be used in large amounts in food, cosmetics, and pharmaceuticals. The LD50 value (50% lethal amount) of the lethal dose of dimethyl silicone oil is more than 35g/Kg. This value is classified according to the toxicity of the American Industrial Hygiene Association, which is equivalent to non-toxic; it also has no chronic poisoning problems and will not be absorbed by the digestive system. No irritation to the membrane; low viscosity dimethyl silicone oil has slight irritation to the cornea, but no harm. Safety data of silicone oil as follow: Types of silicone oil Viscosity (25 °C /mm 2 Ÿ s) Skin irritation (human) Chronic toxicity (rat, 6 ...
In many production processes, problem caused by harmful foams. The presence of these foams reduces the utilization rate of equipment, causes production losses, pollutes the environment, and even affects the normal operation of operations. To eliminate harmful foam, you can use standing, decompression (vacuum), heating or pressurization, chemical defoaming, etc. But when you need to quickly and effectively eliminate foam in a short time, you need to use chemical defoaming. Chemical defoaming does not require a lot of equipment investment and does not need to change the original process. It is the most convenient way of operation. Why are emulsion defoamers layered? Emulsion-type defoamers will delaminate if they are not used for a long time. After delamination, defoamers will affect their use. Why do they delaminate? What are the causes? Emulsion defoamers are physically emulsions and are thermodynamically unstable systems. Layering may occur after long-term storage, but use after...
Defoamers Test Method--- Fermentation Defoamer type: Silicone¨ Polyetherþ fatty alcohol ¨ Mineral oil ¨ Others ¨ 1. Defoamer performance: (Air drum test) Accurately weigh 200ml of foaming medium with a 1000ml measuring cylinder, turn on the air bubble to the specified foam and mention 800ml and record the blank time, then add the prepared defoamer sample, stir it evenly, then turn on the air bubble and record the volume V changes with time. 2. Solid content test (instrument: oven, Surface dish) Turn on the oven, set the temperature to 105°C, wash and dry the watch glass Weigh a certain amount of defoamer sample on the watch glass, and record the weight of the watch glass before and after adding the defoamer as ml and m2 Put the watch glass with the sample in the oven, close the oven after 1h, put the watch glass in the desiccator and cool it, then weigh it as m3; The solid content of the sample is: W=(m3-m1)/(m2-m1)*100% 3 . Viscosity (instrument: mechanical visc...