Problems in emulsified oil blending
November 27, 2022
The emulsified oil is composed of refined high-quality Base Oil, emulsifier, antirust agent, oily extreme pressure agent, stabilizer, bactericide, defoamer, etc. The experiment shows that the stability, emulsifying ability, emulsion stability, antirust and cutting performance of the emulsified oil are not only related to the formulation of the emulsified oil, but also greatly related to the preparation process. Factors to be considered in preparing emulsified oil process:
1. The chemical structure of the emulsifier shall adapt to the chemical composition of the oil phase, and the appropriate dosage shall be determined; 2. The interfacial tension between the two liquids should be small; 3. The viscosity of continuous phase (outer phase) should be high; 4. The adsorption layer between the oil and water interface has a certain degree of mechanical strength and toughness, and has the same charge; 5. Strictly control the preparation process and operation technology; 6. Pay attention to the influence of other additives in the formula on the emulsification performance, such as rust inhibitor.
Pay attention to the following problems in specific operation: 1. Pay attention to the feeding sequence: the oil soluble additives shall be added in the sequence from the ones that are difficult to dissolve to the ones that are easy to dissolve, and shall be heated properly and stirred fully until they are completely dissolved and mixed, but the temperature shall not be too high to avoid the decomposition of additives. 2. When selecting soaps as emulsifiers, attention should be paid to the saponification conditions (temperature, reaction time, stirring speed, etc.). The saponification temperature of fatty acid, high carbonic acid and triethanolamine is generally controlled at 60-70 ℃, and the reaction time is about 30 minutes, while the potassium soap and sodium soap are slightly higher, such as the potassium oleate soap is 80 ℃, 30 minutes; Castor oil sodium soap is 90 ℃, 3h; Rosin sodium soap is 100 ℃, 6-8h. Secondly, as the moisture of emulsified oil has a great impact on the stability of oil base, the moisture in emulsified oil should also be strictly controlled. 3. When the emulsified oil is diluted into emulsion according to the concentration required for use, there is also an emulsification technology problem, that is, how to evenly disperse the oil phase in the water phase. The emulsification process is the process of increasing the oil-water interface and the surface energy, for which a certain amount of work is usually done. At this time, mixing and temperature are very important. The simplest emulsification equipment is the mixing device. If the emulsion is homogenized, its stability will be improved. Practice has proved that when emulsified oil is emulsified, soft water is slowly added in the initial stage of emulsification to make it form a water in oil emulsion first, and the remaining water is continuously added under constant agitation to make the emulsion particles produced by deformation even and fine, and the lotion has high stability and good quality. Secondly, the emulsified oil can also be fully emulsified with a small amount of hot water or steam, and then diluted with cold water. This is because the surface tension of hot water is small, the solubility is strong, and the viscosity is small, which is conducive to the dispersion of the emulsifier, so it is easy to emulsify, while the cold water causes the condensation of the emulsifier on the contrary. 4. After the emulsion prepared according to the use concentration, it is necessary to adjust the PH value of lotion, which is generally about 8-9. The PH value is too high, causing corrosion to aluminum and non-ferrous metals, and irritating the operator's skin; Too low PH value will cause steel corrosion. For this reason, sodium carbonate or triethanolamine is often used to increase the PH value, while oleic acid is used to reduce the PH value. 5. Do not dilute emulsified oil with hard water. Because hard water usually contains salts such as calcium bicarbonate, magnesium bicarbonate, calcium sulfate, magnesium sulfate, etc., when hard water is used to prepare emulsions, the salts react with emulsifiers such as sodium soap, potassium soap, etc. to generate water insoluble soaps and change the performance of emulsions. Therefore, 0.2%~0.3% sodium carbonate shall be added to the hard water for softening, or boiling method shall be adopted to prevent the hard water from demulsification, and improve the cleaning and rust resistance of the emulsion.
