Viscosity grease

Greases Mechanical and rheological behavior and its persistence Consistency and viscosity Mechanical stability Oxidation resistance... 

Apparent viscosity (greases) NFT 60-139 ASTM D 1092 Forced passage of the grease in a capillary tube... 

Lithium hydroxide can be used for preparation of numerous lithium salts. The dominant use is the preparation of lithium stearate [4485-12-5], which is added to lubricating greases in amounts up to about 10% by weight. This salt has very low water solubiHty and extends the acceptable viscosity for the grease to both low and high temperatures (see Lubrication and lubricants). Lithium hydroxide is also used in production of dyes (62) and has been proposed as a source of lithium ion for inhibition of alkaH-aggregate expansive reactivity in concrete (63). 

Oils in Greases. Essentially the same type of oil is used in compounding a grease as would normally be selected for oil lubrication. Petroleum oils are used in about 99% of the grease produced and commonly are in the SAE 20—30 viscosity range with about 100 130 mm /s viscosity at 40°C. Such oils provide low volatiHty for long life at elevated temperatures (50) together with low torque down to subzero temperatures. 

Some quite viscous oils in the 450 650 mm /s are employed for high temperatures. Less viscous oils, down to 25 mm /s and lower at 40°C, are used in special greases for low temperatures. The maximum oil viscosity in a grease for starting medium torque equipment is about 100, 000 mm /s(= cSt) (4). Extrapolations for various oils can be made on viscosity—temperature charts, as shown in Figure 8, to estimate this approximate low temperature limit. 

Apparent viscosity of a grease at low shear rates, eg, below about 10, is approximately equal to the yield stress divided by the shear rate. This... 

Fig. 15. Apparent viscosity vs rate of shear of three greases (53). To convert Pa s to P, multiply by 10.

LDPE homopolymers in the 0.2—150 melt index or 100, 000 20,000 mPa s(= cP) viscosity range. Specialty polymers such as greases and waxes or highly cross-linked polymers are not included. 

The main use of these clays is to control, or adjust, viscosity in nonaqueous systems. Organoclays can be dispersed in nonaqueous fluids to modify the viscosity of the fluid so that the fluid exhibits non-Newtonian thixotropic behavior. Important segments of this area are drilling fluids, greases (79,80), lubricants, and oil-based paints. The most used commercial products in this area are dimethyl di (hydrogen a ted tallow) alkylammonium chloride [61789-80-8] dimethyl (hydrogen a ted tallow)aLkylbenzylammonium chloride [61789-72-8] and methyldi(hydrogenated tallow)aLkylbenzylammonium chloride [68391-01-5]. 

Common uses iaclude pump beariags for water, gasoliae, and solvents having low viscosity high temperatures up to 400°C ia coaveyors and furnaces and ia food, dmgs, and other machinery where oil and grease contamination must be avoided. 

The homopolymer finds a variety of uses, as an adhesive component, as a base for chewing gum, in caulking compounds, as a tackifier for greases, in tank linings, as a motor oil additive to provide suitable viscosity characteristics and to improve the environmental stress-cracking resistance of polyethylene. It has been incorporated in quantities of up to 30% in high-density polyethylene to improve the impact strength of heavy duty sacks. 

Dissolved Solids Boiling Pt/Freezing Point For Liquids/Solid Mixtures Bulk Density Total Solids Content Solids Size Distribution Suspended Solids Content Suspended Solids Settling Rate Dissolved Solids Content Free Water Content Oil and Grease Content Viscosity For Gases Density... 

Grease Manufacture - Selected lube oil fractions arc blended with various metallic soaps to produce high viscosity lubricating greases. 

Figure 52.10 Comparison of the apparent viscosities of a gear oil and a gear grease. The grease flows readily in the tooth-contact region, where shear stress is high, but resists leakage at seals and joints...

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