• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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• pp.306-312
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• 1998

This paper describes syntheses of thickener for di-urea grease using constant velocity joint. The thickeners of di-urea grease were synthesized by reaction of diisocyanate with various alkylamines, hexylamine, octylamine, stearylamine and cyclohexylamine at high temperatxire. The synthesized thickener were analyzed by FT-IR spectroscopy and two kinds of Mass spectroscopy (EI & FAB). Dropping point and Consistency of synthesized di-urea grease were determined.

• Tribology and Lubricants
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• 제19권5호
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• pp.280-284
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• 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.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.179-185
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• 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.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.123-129
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• 2004

Rolling bearings are assorted one of the most important machine elements. The various functions of bearings are greatly influenced by grease, and higher performance of rolling bearing greases is required to improve rolling bearing lubrication. The two conditions for optimum grease synthesis were selected by SSRED (Six Sigma Robust Engineering Design) program by using dropping points and OIT values respectively. And the optimized two urea/ether oil greases were synthesized to compare the performance. The typical physical properties of grease were investigated. And life test of these greases was conducted by rolling bearing grease life tester The characteristics of the greases before and after life test were investigated using FTIR, microscope, SEM, TG/DSC, OIT and TAN meter The optimized two greases showed longer life time than typical urea/ether oil grease. The optimized grease by means of OIT value showed higher performance such as long life time. low TAN value and high oil bleeding amount in comparison with the optimized grease using dropping point.

• Tribology and Lubricants
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• 제21권1호
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• pp.21-26
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• 2005

Rolling bearings are assorted one of the most important machine elements. The various functions of bearings are greatly influenced by grease, and higher performance of rolling bearing greases is required to improve rolling bearing lubrication. The two conditions for optimum grease synthesis were selected by SSRED (Six Sigma Robust Engineering Design) program by using dropping points and OIT values respectively. And the optimized two urea/ether oil greases were synthesized to compare the performance. The typical physical properties of grease were investigated. And life test of these greases was conducted by rolling bearing grease life tester. The characteristics of the greases before and after life test were investigated using FTIR, microscope, SEM, TG/DSC, OIT and TAN meter. The optimized two greases showed longer life time than typical urea/ether oil grease. The optimized grease by means of OIT value showed higher performance such as long life time, low TAN value and high oil bleeding amount in comparison with the optimized grease using dropping point.

• Tribology and Lubricants
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• 제22권5호
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• pp.269-275
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• 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.

• 한국산학기술학회논문지
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• 제21권2호
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• pp.634-643
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• 2020

본 연구에서는 고체윤활제 중 가장 널리 사용되는 폴리테트라플루오로에틸렌(PTFE) 분말의 종류와 투입량에 따른 우레아 그리스의 윤활 및 유변학 특성 변화를 연구하여 최적의 윤활시스템을 구축하고자 하였다. 4,4'-메틸렌 다이페닐 다이아이소사이아네이트(MDI), 올레일아민과 시클로헥실아민을 사용하여 우레아 그리스를 합성하고, 분산법 혹은 현탁법으로 중합된 PTFE 분말을 함량별로 투입하여 그리스를 제조하였다. 제조된 그리스의 기본물성, 유변학적 및 트라이볼로지 특성을 비교하였다. 그 결과, PTFE의 첨가량에 따라 우레아 그리스의 주도값은 감소하지만 변화폭은 분산형 PTFE가 상대적으로 더 큰 것으로 확인되었다. 내열성과 동판부식 영향성에서는 두 가지 PTFE 분말 모두 큰 변화가 없는 것을 확인하였다. PTFE 분말의 함량 증가에 따라 전단점도는 상승하였으며, 분산형 PTFE가 점도 상승에 더 효과가 있음을 확인하였다. 손실계수의 값이 1인 점에서 전단응력은 PTFE 분말이 첨가되지 않은 그리스 보다 첨가된 그리스가 더 높았고, 분산형 PTFE가 현탁형 PTFE보다 더 큰 것을 확인하였다. 두 가지 PTFE 분말 모두 우레아 그리스의 마모 감소 효과에 대한 성능 향상은 낮았지만, 내 하중 성능은 분산형 PTFE는 최대 2.5배, 현탁형 PTFE는 최대 5배의 증대 효과가 있는 것을 확인하였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2003년도 학술대회지
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• pp.129-138
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• 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.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.111-116
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• 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.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1999년도 제30회 추계학술대회
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• pp.247-256
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• 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.