• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2004.11a
• /
• pp.111-116
• /
• 2004

Li-complex and urea type greases (each 10 species) which were furnished by Chang-Am LS, analyzed anti-wear performance into fretting wear tester & four-bail wear tester. from the results of fretting wear test, the wear volume of Li-complex greases are $4.6\~8.9mg\;and\;8.3\~14.4mg$ with the test of urea greases. The anti-wear performance for 4-ball wear test of greases produced results around 0.5mm at the value of WSD. The grease life performance were evaluated by SKF-ROF Grease Tester and wheel bearing life tester. From the results of SKF-ROF tester, the life performance evaluated by whole working time produced results $50\~300hr$ with the Li-complex greases and 100-1000hr with the urea greases. That is to say, in spite of severe condition at the higher of $10^{\circ}C$ reaction temp, the life performance with Urea type greases are much superior to Li-complex type greases. Prior to wheel bearing life tester, the grease selected performance evaluation(=anti-wear test) are tested by wheel bearing tester. In this results, we can confirm results those are similar with SKF-ROF tester. In this study, we can draw two major conclusions, one is that Li-complex greases are superior to urea greases with anti-wear properties and the other is that urea greases are much superior to Li-complex greases with life performance.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2003.11a
• /
• pp.129-138
• /
• 2003

Rolling bearings are classified one of the most important machine elements. The various function of bearings are greatly influenced by grease, and higher performance of rolling bearing greases is required in improve bearing lubrication. Three urea/ether oil greases with identical composition were synthesized to compare the performance of these greases according to the thickener content of grease. The typical grease physical properties were investigated. And life test of these greases was conducted by FE-9 grease life tester. The characteristics of the greases before and after life test were investigated using FT-IR, microscope, OIT and TAN meter. Large differences in the grease performance depending on the content of the thickener were observed. The grease with higher content of the hickener showed higher performance such as long life time and low TAN value. After preliminary test, twelve greases were synthesized and evaluated the performance of dropping point and OIT, then optimized two greases were selected by SSRED (Six Sigma Robust Engineering Design) using dropping point and OIT data. Characteristics of the optimized two greases were on the same level with estimated value. The optimized grease by means of OIT value showed longer grease life in comparison with optimized grease by dropping point. However two greases showed higher performance than typical urea/ether oil.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1999.11a
• /
• pp.247-256
• /
• 1999

This paper describes the results of analysis, syntheses and Roll Stability of various Di-urea greases. Di-urea greases were synthesized by reaction of 4,4'-Methylenebis(phenyl isocyanate) and various amines, such as cyclohexylamine, octylamine, stearylamine and p-toluidine with base oil at 80-180 $^{\circ}C$. The synthesized di-urea greases were analyzed by FT-R spectroscopy. The Roll Stability of synthesized di-urea greases was evaluated.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2003.11a
• /
• pp.139-148
• /
• 2003

In this study, biodegradable base Li-greases were prepared by using Li-soap thickener and vegetable oils such as soybean oil, rapeseed oil, castor oil and synthetic ester. Also, EP-greases were formulated by blending base Li-greases, anti-wear additives, EP additives, anti-oxidants and corrosion inhibitor etc. And EP-greases were characterized by analysing physical properties such as worked penetration, dropping point, 4-ball wear, extreme pressure, thermal properties etc. Biodegradability of base Li-greases and EP-greases were evaluated by CEC-L-33-A-93 method using several inoculums of domestic sewage treatment plant. As the results, biodegradability of vegetable oils were shown at the range of 97.1 to $98.4\%$. And biodegradability of base Li-greases and EP-greases were $86.2\%\;\~\;89.3\%\;and\;83.4\%\;\~\;90.0\%$ which were lower value than those o( vegetable oils due to effect of Li-soap thickener, respectively. Therefore, the EP-greases prepared in this study were easily biodegraded by microorgnism.

• Journal of the Korean Chemical Society
• /
• v.21 no.5
• /
• pp.384-388
• /
• 1977

Clay-polymer thickened greases were made by dispersing bentone-polyethylene and bentone-atactic polypropylene into mineral oil at an adequate temperature, and the physical properties such as wear and water washout characteristics, oxidation and shear stabilities, and dropping point of the greases were tested. Even if the greases failed to meet some properties, it was found that those greases can be used for some special purposes, by observing and comparing the properties with those of clay-metallic soap thickened greases that were made in this experiment.

• Tribology and Lubricants
• /
• v.22 no.5
• /
• pp.269-275
• /
• 2006

Rolling bearings are classified one of the most important machine elements. The various function of bearings are greatly influenced by grease, and higher performance of rolling bearing greases is required to improve bearing lubrication. Three urea/ether oil greases with different composition were synthesized to compare the performance of these greases. The typical grease physical properties were investigated, and life test of these greases was conducted by FE-9 grease life tester. The grease with higher content of the thickener showed higher performance. After these preliminary test, twelve greases were synthesized and evaluated the performance of dropping point and OIT value. And optimized conditions for grease synthesis were selected by SSRED (Six Sigma Robust Engineering Design) using dropping point and OIT value respectively. The optimized grease using OIT value showed longer grease life than that using dropping point. Two greases were synthesized following the optimum synthesis conditions by means of OIT value. Then grease life and other properties of these greases were investigated. These two greasaes showed longer grease life than typical urea/ether oil grease.

• Tribology and Lubricants
• /
• v.19 no.5
• /
• pp.280-284
• /
• 2003

High performance characteristics are required for rolling bearings and the various functions of bearing are greatly influenced by grease. Recently, higher performance is being demanded of rolling bearing greases for bearing lubrication. Four special greases with different composition such as lithium soap/ester oil, urea/ester oil, urea/ether oil and PTFE/fluorine oil were synthesized to compare the performance of these greases with that of the conventional lithium soap/mineral oil grease. The grease properties were investigated using a series of typical grease testing methods and grease life test. After the life test, the greases were charaterized by FTIR analysis and a microscope. And the iron amount in the greases was analyzed by AAS after ashing. The composition and manufacturing process determined the grease performance. The grease with a base oil of synthetic oil showed higher performance and the urea/ester oil and PTFE/fluorine oil showed about three times longer life as compared with conventional lithium grease.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2003.11a
• /
• pp.149-151
• /
• 2003

This report describes the adhesibility of the polyurea greases. Generally, Polyurea greases were divided into three classes, aliphatic, alicyclic, and aromatic, according to the differences of the terminal alkyl group. The adhesion properties of polyurea greases were tested with Adhesion Tester by In-house method.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2001.11a
• /
• pp.179-185
• /
• 2001

High performance characteristics are required for rolling bearings and the various functions of bearing are greatly influenced by grease. Recently, higher performance is being demanded of rolling bearing greases for bearing lubrication. Four special greases with different composition such as lithium soap/ester oil, urea/ester oil, urea/ether oil and PTFE/fluorine oil were synthesized to compare the performance of these greases with that of the conventional lithium soap/mineral oil grease. The grease properties were investigated using a series of typical grease testing methods and grease life test. After the life test, the greases were charaterized by FTIR analysis and a microscope. And the iron amount in the greases was analyzed by AAS after ashing. The composition and manufacturing process determined the grease performance. The grease with a base oil of synthetic oil showed higher performance and the urea/ester oil and PTFE/fluorine oil showed about three times longer life as compared with conventional lithium grease.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2000.06a
• /
• pp.99-105
• /
• 2000

Greases composed of base oil and thickener are widely used in the purpose of lubrication and anti-corrosion of machinery. However, greases are sometimes oxidized and decomposed by heat of friction, and produced organic acid. And the greases leaked out ordinary spot make the concrete structures weaken. In this study, the chemical effects of the greases with the concrete structures were investigated through oxidation reaction under pressure and oxygen, and evaluated by the analysis of TAN, Ca content, FT-IR and XRD of grease and cement powder after the oxidation reaction. As the results, TAN value decreased with the increase of the content of cement because of neutralization of organic acid produced by the oxidation of grease with calcium contained in the cement. The content of calcium linearly increased with the increase of cement due to calcium salt by neutralization of acid. Also, according to XRD results of the cement powder oxidized at 99 $^{\circ}C$, the diffraction peak due to calcium hydroxide decreased in comparison with that at room temperature because of the reaction of calcium and organic acid.