Study On The Foaming Problems Of The Cold Heading Process Lubricant Oil

Cold heading lubricant oil is prone to foaming for long time using. Adding antifoam agent is most commonly used to solve this problem. Different types of antifoamant in the some base oils have different dissolving capacity; moreover the particle size and dispersion uniformity of them are also different. So each lubricant oil has the most suitable antifoamant. Studying on the key factors which influence the antifoaming performance of lubricant oil play an important role in guiding antifoaming additive selection and using.Firstly, through the separation and analysis of the cold heading used oil, the reasons of antifoaming performance failure are studied. Secondly, antifoaming performance of different types of antifoamant in cold heading lubricant oil is contrasted by the bubble experiment, and some factors which influence the antifoaming performance are also studied. Thirdly, Using 2-ethylhexyl acrylate and vinyl acetate as the raw material, benzoyl peroxide as the initiator, the 2-EHA/VAC copolymer is synthesized by random copolymerization in toluene solvent. Finally, a high efficient antifoamant is prepared by compounding synthetic copolymer with fluorosilicone antifoamant.The studies show that saponification powder, drawing powder and silicon antifoamant settlement are the main causes of the lubricant foaming. Different types of antifoam agent have different antifoaming performance. Non-silicone antifoamant PX3841 has a more stable antifoaming property than fluorosilicone antifoamant X101A and compounding antifoamant T922. Dispersion and antifoaming stability of the silicone antifoamant is the worst. The synthetic copolymer with good antifoaming performance can be obtained under the following conditions:0.52:0.48 molar ratio of 2-EHA and VAC,80℃ of the polymerization temperature,6 h of polymerization time and 0.2% (based on total monomers mass) of the dosage of initiator. The copolymer with the number-average molecular from 4.5×104 to 6.0×104 have a good antifoaming performance. By utilizing stable dispersing performance of non-silicone antifoamant and good anti-high temperature performance of fluorosilicone antifoamant, the compounding antifoamant has the best antifoaming performance. Cold heading lubricant oil with this compounding antifoamant is still have a good antifoaming performance after polluted by water, metal chips, saponification powder and drawing powder.