Antibacterial agents to improve the life of water-based metalworking fluids

Laboratory ventilation device to simulate the field conditions, the effects of different antimicrobial agents antimicrobial properties, the results show that a single antimicrobial agent is difficult to both bacteria and fungi from the good inhibition composite antibacterial agents against bacteria and fungi have a good inhibitory effect. Meanwhile, in multi-machine composite antibacterial agents on-site application test, the results showed that the composite antibacterial agent to extend the life of the emulsion and synthetic fluids are up to ten times more. 1 Introduction aqueous metal working fluids (including emulsion, and synthetic fluids) are widely used in the machining industry, it has a good cooling performance and cleaning performance, and low cost, but also easy spoilage, such as shorter life shortcomings. Spoilage is results blooms of bacteria, fungi and other microbes in the water. The microbial blooms undermine the stability of the emulsion, the emulsion reduced use of performance: also lead to a decrease in pH, resulting in corrosion: also have an adverse impact on the operator, such as an unpleasant smell, irritate the skin, allergic reactions . The antimicrobial agent is added to prevent spoilage, improve the water-based metalworking fluid life. Abroad in the Water Fund antimicrobial agent commonly used in metalworking fluids, varieties of dozens of antibacterial agents. The domestic use of antimicrobial agents is still not widespread, the service life of some of the processing liquid in the summer only a week or so. Although many varieties of antibacterial agents used in other areas, but most of them can not be used for processing liquid. The antibacterial agent used for the machining liquid should have the following characteristics: (1) better chemical and physical compatibility with the processing liquid: (2) a degree of stability, in the long period of time from the antibacterial effect: (3) inhibition of bacteria and fungi have a better: (4) low toxicity: (5) an acceptable cost. In this paper, laboratory ventilation device to simulate field conditions of use regularly to detect bacteria and fungi and pH, and record the change in appearance of the processing solution, the screening of various antibacterial agents.Field application test of the composite antibacterial agent while still on multiple machines, regular monitoring of bacteria and fungi, the pH value, the change in appearance and corrosion performance. 2 test laboratory test this integrated foreign representative test methods: each cycle of five days of the sample assessed through air, stop gas two days, made periodically added to the scene and cultured bacteria.Bacteria, fungi, and pH were measured after the end of each cycle. Deterioration of the sample indicators: total bacterial count> 107 / ml, fungi total number of> 103 / ml.Laboratory test conditions: (1): comply with the requirements of the biological tests. (2) Equipment: ventilation apparatus, pH meter, incubator, colony counter and inoculation test bench. (3) Metalworking Fluids: The hardness of 100 ~ 150mg / L (calcium carbonate) was diluted with water the emulsion concentrate, and the dilution factor of 20.(4) assessment of samples: in the metalworking fluid, adding a variety of antimicrobial agents, as shown in Table 1. (5) Strain: obtained from the scene of the deterioration of the metalworking fluid, and cultured in the above-mentioned metal processing liquid to the total bacterial count> 5 × 108 / ml, fungi total number of> 104 / ml in. Field application test field application testing in the summer of 1997 in Beijing First Machine Tool Plant, composite antibacterial agent dose of 0.10% is added to the emulsion and synthetic fluids, two grinders use test, regular monitoring of bacterial and The number of fungi, pH value, the appearance of change and anti-rust properties (a cast iron, 35 ± 2 ℃, 48h, monolithic). Table 1 assessment sample numbers type of antimicrobial agent concentration (%) Remarks a nitrogen-containing heterocyclic compounds Ⅰ 0.07 reference to the manufacturer's recommended concentration of nitrogen-containing heterocyclic compounds Ⅰ 0.103 nitrogenous heterocyclic compounds Ⅱ 0.134 nitrogen-containing heterocyclic compounds II 0 .195 0.0166 composite antibacterial agent sulfur compounds 0.100.07% nitrogen-containing heterocyclic compounds Ⅰ +0.016% sulfur compounds + small amount of stability synergist 7 - pure metalworking fluids test results 1) the antibacterial properties of the antimicrobial agent antibacterial agents listed in Table 1 the antibacterial effects of the test, the test results are shown in Table 2. Bacteria and fungi from Table 2 Total number of metamorphic term, the sample No. 7 does not add an antibacterial agent against bacteria and fungi have no inhibition: have some inhibitory effect of various antibacterial agents against bacteria or fungi.Wherein: (1) 1 to 4, samples are fungi first exceeds the deterioration indicator described nitrogen-containing heterocyclic compounds I and II inhibition superior to the inhibition of fungi of bacteria: and 2,4 sample No. metamorphic respectively the high dose of the antibacterial agent in the dose range selected its antibacterial effect better than the sample length 1,3. (2) Sample No. 5 is a bacteria exceeds deterioration indicator, no significant growth of fungi in six weeks, this sulfur-containing compound will be described have a good inhibitory effect on fungi, while the inhibition of bacteria is not obvious. (3) 6 samples after up to 20 weeks of the trial is still degenerate. Obviously, aza ring compounds I and sulfur compounds composite using a significant synergistic effect, have excellent inhibitory effect on bacteria and fungi. Table 2 laboratory test results Number assessment project beginning point one week Wednesday, Thursday, Friday and Saturday 20 week seven weeks and eight weeks 10 weeks 22 eleven weeks weeks weeks metamorphic phase 1 the total number of bacteria,