Influence of soap/polymer concentration ratio on the rheological properties of lithium lubricating greases modified with virgin LDPE

The main goal of this work was to study the feasibility of using a low-density polyethylene (LDPE) as additive to improve the rheological properties of lithium lubricating greases. The combined effect that both soap and LDPE concentrations exerts on the rheology of lithium lubricating greases and its relationship with grease microstructure were studied according to an experimental design based on the response surface methodology (RSM). Different lubricating grease formulations were manufactured by modifying lithium 12-hydroxystereate and LDPE concentrations. Small-amplitude oscillatory shear (SAOS) and viscous flow measurements, as well as mechanical stability tests, were performed. In addition to these, environmental scanning electronic microscopy (ESEM) was used to determine grease microstructure. LDPE was found to be a useful additive to modify grease rheology, acting as filler in the entangled soap network. The values of both apparent viscosity and linear viscoelasticity functions increase with soap and LDPE concentration. However, the addition of LDPE distorts soap microstructural network, yielding greases with lower relative elastic characteristics.     

利用废油脂制备钠基润滑脂的初步研究

利用废油脂采用直接法制备出钠基润滑脂,确定了利用废油脂制备钠基润滑脂的最佳配方及工艺条件。使用差动热分析仪对合成出的润滑脂进行了滴点测试,并对其外观简单鉴别,结果表明,利用废油脂替代硬脂酸等脂肪酸制备钠基润滑脂产品是可行的,为废油脂的合理利用开辟了新的途径,但合成的钠基润滑脂滴点较低。在以后的研究中可以尝试制备钙基、钙-钠复合基或锂基润滑脂,以提高润滑脂的滴点和其他性能。     

高抗水淋连铸机润滑脂的研制

结合连铸机高温、高负荷、有水淋的苛刻工况,通过对润滑脂基础油、稠化剂以及其他添加剂的考察和筛选,确定了一种高抗水淋连铸机润滑脂的配方。经润滑脂理化性质的试验研究以及在国内某钢铁厂连铸机润滑系统的应用,表明高抗水淋连铸机润滑脂不仅具有良好的抗水、防锈、抗腐蚀性能,且具有良好的极压性、剪切安定性、机械安定性及高温性能,可满足连铸机的使用要求。     

Impact of polydimethylsiloxanes on physicochemical and tribological properties of naphthenic mineral oil(KN 4010)-based titanium complex grease

Titanium complex greases were prepared by using naphthenic mineral oil and polydimethylsiloxane as the mixed base oil. The effect of polydimethylsiloxane molecular weight and polydimethylsiloxane content in mixed base oil on the physicochemical and tribological properties of titanium complex greases was investigated.As compared to the sole mineral oil-based titanium complex grease, the use of polydimethylsiloxane(H201-350)as a co-base oil increased the dropping point from 310 to 329 °C, decreased the oil separation from 3.7% to 2.3%,reduced the corrosion extent, and obviously improved the tribological properties. When the mixed oil-based titanium complex grease was used as a lubricant, lubricating films of polydimethylsiloxane were probably formed on the surfaces of friction pairs, giving good lubricating property.     

Recycled and virgin LDPE as rheology modifiers of lithium lubricating greases: A comparative study

In this work, a new application for recycled low‐density polyethylene (LDPE), as rheology modifier of standard lithium lubricating grease formulations, was studied. The effectiveness of this additive was compared with that achieved with a virgin LDPE. With this aim, both types of polymers were added to the formulation during the manufacturing process of greases, following the same standard protocol, to reinforce the role of the thickening agent, the lithium 12‐hidroxystearate. The effect that both lithium soap and LDPE concentrations exert on the rheology of lubricating grease formulations and its relationship with grease microstructure were discussed. Lubricating greases were rheologically characterized through small‐amplitude oscillatory shear and viscous flow measurements. In addition to these, scanning electron microscopy observations and mechanical stability tests were also carried out. In all cases, an increase in soap concentration yields higher values of apparent viscosity and linear viscoelasticity functions. On the other hand, the values of the rheological functions obtained for recycled LDPE‐based lubricating greases are, in general, higher than those obtained for virgin LDPE‐based grease formulations. However, the structural skeleton developed in greases containing recycled LDPE demonstrates less resistance to severe working conditions, showing lower mechanical stability than virgin LDPE‐based grease formulations. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Fractionation of animal fat glycerides by crystallization from acetone. Am improved lard oil

Summary Various edible and inedible grades of animal fats, such as lard, grease, tallow, and selectively hydrogenated lard, grease and tallow were separated into “oils” and “stearins” by crystallization from acetone. The chemical and physical properties as well as the yields of oils and stearins obtained by this method are described. Antioxidants and metal deactivators are much more effective in stabilizing lard and grease oils produced from partially hydrogenated fats than in stabilizing corresponding products from unhydrogenated fats. Report of a study certain phases of which were made under the Research and Marketing Act of 1946. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, United States Department of Agriculture.     

Synthesis of polyphenylmethylsiloxanes and their enhancement on tribological properties of titanium complex grease

Polyphenylmethylsiloxanes (PPMSs) with the phenyl/methyl mole ratios of 0.25:1–0.75:1 were facilely synthesized using phenylmethyldichlorosilane, diphenyldichlorosilane, dimethyldichlorosilane, and hexamethyldisiloxane as the raw materials with the hydrolysis-condensation method. The molecular weights (M _w) of the as-synthesized PPMSs ranged from 1248.7 to 27 014.0. The maximum molecular weight was obtained at the phenyl/methyl ratio of 0.65:1. Titanium complex greases were prepared by using titanium carboxylate as the thickener and PPMS/mineral oil (KN4010) as the mixed base oil. When the weight percentage of PPMS (phenyl/methyl mole ratio of 0.45:1) in the mixed base oil was 20%, the dropping point of the resultant titanium complex grease increased by 21 °C as compared with the sole mineral oil-based titanium complex grease. The friction coefficient and the wear scar dimension were 0.54 and 0.69 times those of the sole mineral oil-based titanium complex grease, respectively. According to thermogravimetric analysis–differential scanning calorimetry analysis, the working temperature of the titanium complex grease could reach 240 °C. The addition of PPMS in the titanium complex grease obviously improved its thermal stability and tribological properties. The present work developed a new category of titanium complex grease using PPMS and mineral oil as the mixed base oil. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47168.     

Assessment of the Lubricity of Grease-Sealing Rotary Shaft Seals Based on Grease Properties

Grease-lubricated sealing systems have an increased risk of starved lubrication. For this work, the lubricity of 23 greases in a rotary shaft sealing system was evaluated with a new test and evaluation method. The lubricity was then correlated with rheological and other grease properties. These grease properties are either available by the data sheet or can be measured with low effort. The results of the correlation allow a preselection of greases which are expected to lubricate rotary shaft seals well. This can support manufacturers and users in considering the lubrication of the sealing system early in the development process.     

Lubricating greases

Summary A brief review has been given of the principal types of lubricating greases and of the fatty materials used therein. No attempt has been made to include a discussion of all conditions which may affect grease structure. However it has been indicated that various factors, as far as the grease itself is concerned, influence performance because they either affect the size and shape of the dispersed particles of the thickening agent, or affect the solubility relationship between the dispersed particles and the oil.     

The effect of recycled polymer addition on the thermorheological behavior of modified lubricating greases

This article deals with the influence of temperature on the rheological behavior of lithium lubricating greases modified with three different types of recycled polymers, high‐density polyethylene (HDPE), low‐density polyethylene, and polypropylene (PP), all deriving from waste plastic recycling plants. Grease formulations containing diverse polymers were manufactured and rheologically characterized. Small‐amplitude oscillatory shear and viscous flow measurements over a temperature range of 25–175°C were carried out. The experimental results obtained suggest that a blend of HDPE and PP could be considered a suitable potential viscosity modifier for lithium lubricating greases in a wide range of in‐service temperature. Thus, the lubricating greases studied modified by HDPE or PP show quite promising results at low or high temperature, respectively. In addition, thermomechanical reversibility has been studied by applying different combined stress–temperature protocols. Lubricating greases containing any of the recycled polymers studied show a significant irreversible structural breakdown when the sample is submitted to temperatures and stresses higher than 75°C and 200 Pa, respectively. Regarding lubricating grease viscous flow behavior, a minimum in the shear stress versus shear rate plots appeared at temperatures above 50°C, more pronounced as temperature increased, resulting from material flow instabilities. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers.     

Low-temperature properties of alkyl esters of tallow and grease

The low-temperature properties of mono-alkyl esters derived from tallow and recycled greases were determined for neat esters and 20% ester blends in No. 2 low-sulfur diesel fuel. Properties studied included cloud point, pour point, cold filter plugging point, low-temperature flow test, crystallization onset temperature, and kinematic viscosity. Compositional properties of the alkyl esters determined included water, residual free fatty acids, and free glycerol content. In general, the secondary alkyl esters of tallow showed significantly improved cold-temperature properties over the normal tallow alkyl ester derivatives. The low-temperature flow test did not show a 1:1 correlation with cloud point as previously observed with methyl soyate and methyl tallowate. For the homologous series methyl to n-butyl tallowate, ethyl tallowate had the best broad-spectrum low-temperature properties, both neat and when blended in diesel fuel. For the greases studied, both the normal and branched alkyl ester derivatives showed improved properties over corresponding tallow esters, especially with neat esters.     

The use of animal fats in poultry feeds

Summary White grease, prime tallow, and soybean oil have been fed to chicks and to turkey poults at the levels of 2.2 to 5.0%. No consistent improvement in growth has been observed with chickens. A slight improvement was noted with turkeys with prime tallow. However feed utilization was improved when the various levels of fat were fed to either chickens or turkey poults. The addition of fat to poultry feeds reduces the amount of dust and improves the texture and color of the feed. Published with the approval of the director of the Agricultural Experiment Station, College of Agriculture, Madison, Wis.     

Continuous lithium and aluminum stearate grease manufacture

Summary 1. Lithium and aluminum greases can be made continuously by using heating, cooling, gelling and working stages in series. Votators can be used successfully for heating, cooling and working. The entire process from slurry to finished grease takes about 20 minutes, most of which time is in the gelling section. 2. The source and refinery treatment of the oil and the type of soap affect the process appreciably.     

Production of alkyl esters from tallow and grease using lipase immobilized in a phyllosilicate sol-gel

The lipase-catalyzed synthesis of alkyl esters from tallow and grease using Pseudomonas cepacia lipase (PS-30) immobilized within a phyllosilicate sol-gel matrix was investigated. The effects of the presence of alcohol and of the amount of enzyme used were studied. The matrix-immobilized PS-30 lipase effectively converted grease and tallow to ethyl esters in greater than 95% yield when using ethanol. The final conversion of grease or tallow to alkyl esters was aided by the addition of molecular sieves (0.4 wt% of substrates) to the reaction mixture. The matrix-immobilized PS-30 enzyme was easily recovered and could be reused at least five times without losing its activity. Accordingly, the phyllosilicate sol-gel immobilized PS-30 lipase is potentially useful for the economic production of biodiesel fuel.     

The dual-solvent extraction of wool grease with hexane and aqueous isopropanol

Hexane solutions of three wool greases of different purities—(a) B.P. grade, (b) a typical commercial grade, and (c) a very crude grease-were extracted by countercurrent flow of aqueous isopropanol (60% v/v IPA) in a 12-stage mixer-settler pilot plant. Fractionation performance was in close agreement with that predicted by an ex-traction model developed previously. Concentrations of detergent in the product greases were 0.00%, 0.00% and 0.43%, respectively. However, even with the crude grease the concentration of detergent oligomers with more than 7 ethoxylate units was zero; free acids content was slightly reduced; and the free cholesterol content was unaffected. The color of the wool grease was improved by solvent extraction, but the bleachability was only marginally improved. The complete removal of detergent oligomers indicates that the extrac-tion technique will improve the water-emulsifying capacity of cer-tain wool greases and overcome the synergism responsible for hyp ersensitivity.     

Comparison of fat-splitting reagents in the twitchell process

Summary Commercial petroleum sulfonic acid reagents have been compared with Twitchell reagents, alkylarylsulfonic acids, and sulfoarylstearic acids as fat-splitting reagents in the hydrolysis of lard oil, tallow, cotton-seed oil, garbage grease, and inedible grease. The best reagents were made from commercial wetting agents of the alkylarylsulfonate type. Sulfoxylylstearic acid, seven petroleum sulfonic acids, and four Twitchell reagents followed in decreasing order. Observations have been made on the distribution of the fat-splitting reagent between phases, the necessity of removing the sweet water after a certain degree of hydrolysis, and the effect of the fat-splitting reagent upon the color of the crude fat acids. This is one of four Regional Research Laboratories operated by the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, United States Department of Agriculture.     

碳酸钙粉体设备开式齿轮跑合润滑脂研制应用

针对碳酸钙粉体设备中开式齿轮在跑合阶段的工作特性和工况的分析,以及跑合阶段开式齿轮对润滑脂所要求的性能;利用基于模糊集合理论的模糊层次分析法(FAHP),对润滑脂的基础油和添加剂进行优选。采用Ⅱ类基础油650SN与聚内烯烃(PIO)复合作为研制润滑脂基础油,以及适量添加剂,研制出碳酸钙粉体设备跑合阶段工况使用的专用跑合润滑脂。并通过现场多台不同型号设备试用,证明能很好满足使用要求。     

Laocs news feature Shortages and regulations: headaches for toilet soap formulators

The formulator is faced with shortages in soap stock fats and oils and must juggle the merits and costs of less common oils, lower grade greases, and synthetics as substitutes for familiar beef tallow and coconut oil. Best compromises must be made by the perfumer for essential oils no longer obtainable to maintain quality and to preserve the odor image of soap products. The formulator must have in vitro, in vivo, and safety data for soap additives. All through development, the formulator must remember that, having made it, he must prove it. Efficacy tests must be more detailed and closer and closer to life.     

Animal fat raw materials

Over six billion pounds of tallow and grease are produced yearly in the United States, and almost 90% of these animal fats are utilized in feeds and as raw materials for industrial chemicals—both domestically and abroad. The fatty acid profile of an animal fat is a function of the kind of animal from which the fat was derived, as well as the breed, age, and diet of the animal. Impurities in the fat determine its grade and depend primarily on this history of the fat as well as on external contaminants which may have been added inadvertently.     

Detection of lard and randomized lard as adulterants in refined-bleached-deodorized palm oil by differential scanning calorimetry

A study was conducted to assess the use of differential scanning calorimetry (DSC) for detecting the presence of lard/randomized lard as adulterants in refined-bleached-deodorized (RBD) palm oil. Lard extracted from the adipose tissues of pig was chemically interesterified using sodium methoxide as catalyst. DSC thermal profiles of both genuine lard and randomized lard were compared with those of other common animal fats such as beef tallow, mutton tallow, and chicken fat. Lard and randomized lard were then blended with RBD palm oil in two series, in proportions ranging from 0.2 to 20%, and DSC analyses were obtained. The DSC cooling profiles of adulterated RBD palm oil samples showed an adulteration peak corresponding to lard/randomized lard in the low-temperature region. This peak was confirmed as an indicator of the presence of lard in RBD palm oil since similar experiments carried out using other common animal fats such as mutton tallow, beef tallow, and chicken fat showed that the lard adulteration peak could be distinctly identified. Using this method, a detection limit of 1% lard/randomized lard was reached (P<0.0001).