ADDINOL Greases and Pastes

ADDINOL offers a wide range of high-performance greases and pastes suitable for use under various operating conditions in automotive and industrial applications. In addition to the typical application area of roller and plain bearing lubrication, the ADDINOL range also includes greases for the lubrication of open and closed gearboxes, wheel flanges of rail vehicles, wire ropes and elastomeric sealing materials.

The product range of ADDINOL Greases and Pastes

  • Multi-purpose greases without additional solid lubricants
  • Multi-purpose greases with solid lubricant additives
  • Liquid greases without additional solid lubricants
  • Liquid greases with solid lubricants
  • Lubricating greases for fast rotating bearings and cryogenic applications
  • Synthetic greases for high temperature applications
  • Greases for special applications
  • Lubricating greases for the food industry
  • Quickly biodegradable lubricating greases
  • Pastes

You will find an overview of lubricating greases and pastes in our Oil Finder.

Greases in cartridges
Selection of ADDINOL lubricating greases in cartridges

Your benefits at a glance: 

  • Reliable wear and corrosion protection of machine elements even under demanding operating conditions such as extreme operating temperatures, shock loads, vibrations, high humidity and dusty environments.
  • High economic efficiency due to optimised energy efficiency and ageing stability
  • Consistently high product quality on the basis of selected base components and high-performance additives in conjunction with sophisticated in-house quality testing during the manufacturing process
  • Expert and individual advice from our application technology department

Information about lubricating greases

Composition of lubricating greases

Lubricating greases are semi-liquid to solid lubricants which are produced by introducing a suitable thickening agent into a liquid base oil. Certain properties of a lubricating grease can also be specifically improved by adding additives and solid lubricants. Compared to lubricating oils, lubricating greases are more complex lubricants in terms of their basic structure. The performance of a lubricating grease is influenced by the properties of all its individual components, such as base oil, thickener, additives and solid lubricants. The multitude of possible combinations of different base oils in different viscosities with different thickener types and different additives allows the production of a large number of different lubricating greases.

The structure of lubricating pastes is basically similar to the structure of lubricating greases. In contrast to greases, however, lubricating pastes always contain a high proportion of solid lubricants. Although many lubricating pastes contain thickener components which are also used in lubricating greases, the use of a thickener in the production of a paste can be dispensed with by using certain types of solid lubricant. The consistency of such thickener-free lubricating pastes is then achieved exclusively by the amount of solid lubricant contained.

The main component of a lubricating grease can be considered to be the base oil contained, the proportion of which in the final end product is typically in the range between 70% and 95%.

Depending on the thickener type selected and the desired consistency of the grease (which in turn is characterized by NLGI classes), lubricating greases contain a proportion of thickeners in the range of 3% to 30%. The proportion of added additives can be up to 10%. If a lubricating grease contains solid lubricants, their proportion is a maximum of about 10%.

Consistent lubricants with solid lubricant contents greater than 40% are classified as pastes. For fat-like special products with a solid lubricant content between 10% and 40%, the term grease paste is commonly used.

Composition of greases
Basic components of a lubricating grease

Base oils for lubricating greases

The base oil as the main component of a lubricating grease has a significant influence on its lubricating and service properties. The thermal and oxidative resistance of the base oil influences the usable temperature range and the ageing stability of the grease. Lubricating greases for low-temperature applications contain selected base oils with a particularly low pour point. The viscosity and viscosity-temperature behaviour of the base oil are important influencing factors for the formation of load-bearing lubricating films and the torque behaviour of the grease under the respective operating conditions. In addition, compatibility with elastomer sealing materials also depends on the base oil selected.

The following base oil types can be used in lubricating greases:

  • Mineral oils (naphthenic oils, paraffinic oils, aromatic oils, white oils)
  • Synthetic oils (polyalphaolefin, ester, polyalkylene glycol, polyisobutylene, silicone oil, perfluoropolyether)
  • Vegetable oils (rapeseed oil)

Base oil mixtures of mineral oils with synthetic oils can also be used for fat production, which ultimately results in semi-synthetic products.

Thickening agent

The thickening agent used influences the texture of a grease, its mechanical stability, its resistance to media (e.g. water, solvents) and last but not least its temperature range. The most frequently used thickeners can be classified as soaps. Soaps are metal salts of fatty acids (aliphatic monocarboxylic acids) formed in a chemical reaction of these fatty acids with a metal hydroxide. The hydroxides of the metals sodium, lithium, calcium, barium and aluminium are mainly used for the production of lubricating greases. A distinction is also made between simple soaps, mixed soaps and complex soaps. If a fatty acid is reacted with a single metal hydroxide, a simple soap is obtained. If two different metal hydroxides are used simultaneously, a mixed soap is formed (e.g. lithium calcium soap). Single and mixed soaps contain only the fatty acids mentioned above. In contrast, complex soaps are produced by reacting a corresponding metal hydroxide with a fatty acid and a second acid that does not belong to the fatty acid group. In addition to the soaps described, other organic and inorganic compounds can also be used as thickeners. Frequently used organic non-soap thickeners include polyurea and polytetrafluoroethylene (PTFE). Frequently used inorganic non-soap thickeners include bentonite and silica gel.

Different greases in a petri dish
NLGI class 00 (left) grease next to grease of NLGI class 2 (right)

Depending on the amount of thickener added, lubricating greases can be produced in various consistencies. Consistency is a measure of the plasticity of a grease and determines its strength and flexibility. Grease consistencies are measured by cone penetration according to DIN ISO 2137. A lower consistency results in a higher measured value for cone penetration. Depending on the measurement result obtained, lubricating greases are divided into different consistency classes, the so-called NLGI classes. The assignment of a measured cone penetration to a defined NLGI class is carried out according to DIN 51818. Greases of NLGI classes 000, 00 and 0 are referred to as free-flowing greases due to their low consistency. They are often used for the lubrication of open or closed gearboxes. Greases with medium consistencies in NLGI classes 1, 2 and 3 are typical rolling bearing greases. Greases with higher consistencies in NLGI classes 4 and 5 or in the highest NLGI class 6 (so-called block greases) are hardly used today.

In preparation for a measurement of the cone penetration mentioned, the grease to be tested is first rolled through with the aid of a grease kneader (see figure below). The grease kneader is filled with a defined amount of grease and the screen disc in the grease kneader is then moved with 60 double strokes at 25°C through the grease contained. The grease contained in the sealed grease kneader is pressed through the holes of the sieve disc and thus subjected to a defined mechanical load.

Grease kneader for a fulling penetration test
The grease kneader prepares the grease for the fulling penetration test

The cone penetration is then measured using a penetrometer. For this purpose, the fat, which has been milled with 60 double strokes, is filled into a beaker at 25°C and the tip of a standardized test cone is placed on the fat surface. After loosening the test cone lock on the penetrometer, it can penetrate the grease for a period of five seconds. After these five seconds, the penetration depth of the test cone into the grease is determined with an accuracy of 0.1 mm. Equivalent to the term "cone penetration", the term "fulling penetration after 60 double strokes" is also commonly used.

Use of a penetrometer in a laboratory
The penetration test in the penetrometer determines the consistency of lubricating greases

The measurement result obtained for cone penetration can subsequently be assigned to one of nine NLGI classes predefined by the National Lubricating Grease Institute (NLGI):

NLGI ClassCone penetration
0.1 mm
000445 - 475
00400 - 430
0355 - 385
1310 - 340
2265 - 295
3220 - 250
4175 - 205
5130 - 160
685 - 115 1)
1) Rest penetration instead of cone penetration
Cone penetration different greases
For NLGI class 00 grease (left), the cone penetrates much deeper than for NLGI class 2 grease (right)

Additives in lubricating greases

By adding additives, the service properties of lubricating greases can be optimised, particularly with regard to adhesion, ageing stability, corrosion protection, wear protection and load carrying capacity.

The following additive types are currently used in lubricating greases:

  • Oxidation inhibitors to improve ageing stability
  • Corrosion inhibitors
  • Pourpoint depressants for improving low temperature properties
  • Additives to improve the adhesive strength
  • AW additives (Anti-Wear additives)
  • EP additives (Extreme-Pressure additives)

Solid lubricants in greases

In contrast to additives, solid lubricants contained in grease are not dissolved in the base oil. In general, solid lubricants can be divided into the groups of layer-forming and non-layer-forming solid lubricants. Layer-forming solid lubricants have a layer lattice structure in which the individual layers formed in the crystal lattice can be easily displaced relative to one another along sliding planes. These layer-forming solid lubricants include, for example, graphite, molybdene disulphide (MoS2), tungsten disulphide (WS2) and α boron nitride (BN). In addition, however, materials are also used as solid lubricants which do not form layer lattice structures. These include soft, ductile metals such as copper and aluminium, white solid lubricants (phosphates, carbonates, sulphides, oxides) and polytetrafluoroethylene (PTFE). Lubricating greases with solid lubricant additives are particularly advantageous when the lubricating condition of boundary lubrication cannot be avoided in applications. Corresponding applications typically have low speeds of motion with high specific loads at the same time.

DIN standards for lubricating greases

There are two essential DIN standards for lubricating greases, which predefine basic classifications and requirements:

  • DIN 51825: Lubricants - Lubricating greases K - Classification and requirements
  • DIN 51826: Lubricants - Lubricating greases G - Classification and requirements

The DIN 51825 standard applies to lubricating greases for the lubrication of rolling bearings, plain bearings and sliding surfaces in NLGI classes 1 to 4. The DIN 51826 standard applies to lubricating greases for the lubrication of drive technology elements (in particular closed gears) in NLGI classes 000 to 2.

In accordance with DIN 51502 (which is also considered in the above-mentioned standards DIN 51825 and DIN 51826), greases can also be marked according to a specified set of rules, which is based on a sequence of code letters and code numbers. A lubricating grease K (according to DIN 51825) with additives of EP additives and solid lubricants, which contains a base oil of synthetic hydrocarbons, has a consistency in NLGI class 2 and an operating temperature range from -30°C to +140°C, would have to be marked with "KPFHC 2 N-30" according to this code.

The following table shows a detailed overview of the code letters and code numbers defined according to DIN 51502 for the identification of greases:

Code letter /
Product specification
Possible code letters and code numbers acc. to DIN 51502Example marking KPFHC
 2 N-30
Code letter Grease typeK ... Grease for rolling bearings, plain bearings and sliding surfaces according to DIN 51825

G ... Grease for closed gears according to DIN 51826

OG ... Grease for open gears

M ... Grease for plain bearings and seals

K
Additional letter AdditiveP ... addition of EP additives

F ... addition of solid lubricants

PF
Additional letter Basic oil typeWithout ... Mineral oils

HC ... Synthetic hydrocarbons

PG ... Polyglycols

E ... Organic esters

PH ... Phosphoric acid ester

FK ... Perfluorinated oils

SI ... Silicone oils

X ... Others

HC
NLGI ClassThe code number corresponds to the numerical value of the NLGI class2
Upper operating temperature and water resistanceC-U ... Upper operating temperature in °C

Water resistance according to DIN 51807

N
Lower operating temperature in
°C
The code number corresponds to the numerical value of the lower operating temperature-30

More precise breakdown of operating temperature and water resistance:

Code letterUpper operating temperatureWater resistance according to DIN 51807
C+60°C0-40 or 1-40
D+60°C2-40 or 3-40
E+80°C0-40 or 1-40
F+80°C2-40 or 3-40
G+100°C0-90 or 1-90
H+100°C2-90 or 3-90
K+120°C0-90 or 1-90
M+120°C2-90 or 3-90
N+140°CIn agreement
P+160°C
R+180°C
S+200°C
T+220°C
U> 220°C

Use of lubricating greases

Compared to lubricating oils, lubricating greases are characterized by higher adhesion and lower flowability. They thus remain more easily at lubrication points which cannot be sealed in a suitable manner due to a high design effort in order to prevent the flow away of alternatively usable lubricating oils from the lubrication point. Rolling bearing lubrication is one of the main areas of application for lubricating greases. In grease-lubricated rolling bearings, the grease used performs an additional sealing function and protects the bearing against environmental influences such as high dust loads, high humidity or splashing water. In contrast to lubricating oils, which can be circulated in oil circulation systems and can therefore perform transport functions in addition to their primary function as a lubricant, lubricating greases are not suitable for removing heat, impurities or wear particles of comparable size from the lubrication point.

Grease sticks at rolling bearing
Lubricating greases are often used for rolling bearings

Contact

Dr. Peter Thiel

Application Technology