DE2306663B2 - Lubricating greases - Google Patents

Description

The present invention relates to new, particularly permanent lubricating greases and to a method to manufacture the same.

Until now, most lubricating greases have been made from mineral or synthetic oily bases or base oils with the addition of thickeners to achieve the desired consistency. Soaps of fatty acids or inorganic agents such as colloidal are mostly used as thickeners Silicon oxide, bentonite, etc., are used.

These known lubricating greases are gels, the thickener forming a network which the oil records. In making a homogeneous and stable gel, however, one encounters several reasons Factors such as B. the type of thickener, the type of base oil, the respective The amount of these components, the manufacturing process for the grease, etc., for difficulties. The influence of the various factors is still largely unknown.

The introduction of polymers in the lubricating greases to improve some of their properties has therefore led to new difficulties. So one has z. B. some olefin polymers, namely polymers of ethylene or propylene or copolymers of ethylene with higher 1-OIefinen than Thickening agents have been suggested, but the gels obtained are not durable enough and break easily under mechanical stress, whereby a product that is too flowable is formed (see US Pat. No. 31 12 270). On the other hand, it has been observed that polyisobutylenes produced by low pressure polymerization are not suitable as thickeners, and attempts to use these polymers The production of lubricating greases has failed (see DT-PS 10 91 683).

From DT-OS 19 55 951 a thickened lubricating grease is also known, which is a lubricating liquid which contains an isobutylene polymer having an average molecular weight of 800 to 1900 and a thickening agent which is comprised of a metal soap salt complex of 12-hydroxystearic acid and a low molecular weight organic acid selected from the group consisting of carboxylic acid and hydroxycarboxylic acid containing no more than 5 carbon atoms or a soap-free thickener. It has however, it has been found that the wear index of such lubricating greases leaves something to be desired.

Lubricating grease compositions which have an oil as the main component also show the same disadvantage with a lubricant viscosity and additionally a reaction product of a copolymer v ^ n ethylene and an added ester with an alcoholate of aluminum, titanium, zinc, calcium or contain magnesium. Such a grease composition is described in US Pat. No. 3,422,015.

It has also been suggested to incorporate certain polymers in the lubricating grease in order to Escape of the fats and the separation of the oil from the network formed by the thickener impede. Such compositions generally contain less than 10 to 12 percent polyisobutylene with an average molecular weight of over 2500, in particular from 10,000 to 11,000.

The introduction of these polymers in the lubricating grease means a new measure, which is based on affects the manufacture of these fats and some of their properties. It has also been established that the introduction of polymers into the fats is a critical process, and also have the obtained products have some disadvantages in terms of their performance.

The invention is a lubricating grease that consists of

a) 2 to 15 percent by weight aluminum soap,

b) 25 to 98 percent by weight hydrogenated or non-hydrogenated polybutene or polyisobutylene with an average molecular weight of 300 to 2500 and

c) 0 to 60 weight percent lubricating oil carrier

consists.

Another object of the invention is a process for the production of lubricating greases, which is now characterized in that 2 to 15 percent by weight of aluminum soap, based on the

weight of the composition, dispersed in 10 to 50 percent by weight of a polymer of hydrogenated and nicnt hydrogenated polybutene and polyisobutylene with an average molecular weight of 300 to 2500 at a temperature of about 15 to 50 ^c C, the dispersion obtained is gradually heated and its 0 to 60 percent by weight Lubricating oil carrier feeds as soon as a temperature of about 90 to 110 ° C is reached that 15 to 48 percent by weight of a hydrogenated and non-hydrogenated polybutene and polyisobutylene with an average molecular weight of 300 to 2500 are added as soon as the temperature, which during the entire addition of the polymer the same height is maintained, has reached about 150 to 180 ° C, that this mixture is cooled and homogenized at about 10 to 35 ° C.

The greases of the present invention have been found to be up to 98 percent by weight to the grease, a polymer of butene or isobutylene with a relatively low molecular weight may contain in a mixture with an aluminum soap as a thickener, smooth, are homogeneous and particularly resistant, which makes them ideally suited as lubricating greases. This result is unexpected, since it was customary in the prior art to use polymers with a high Using molecular weight and adding only small amounts thereof to avoid an adverse effect to avoid the resistance and the lubricating effect of the grease.

The aluminum soap or thickener is generally used in amounts of from about 2 to 15 percent by weight, in particular from about 3 to 8 percent by weight, based on the total weight of grease is used. This aluminum soap is mostly a saturated or unsaturated soap higher aliphatic carboxylic acid of about 12 to 20 carbon atoms, e.g. B. stearin-, olein-, ricinolein- or palmitic acid. Mixed aluminum soaps, which are made from a higher aliphase, can also be used Carboxylic acid and obtained from a carboxylic acid having a low molecular weight, be used. Such aluminum soaps are e.g. B. Soaps of benzostearic, toluene stearic or acetopalmitic acids. The latter is, for example, a mixture of a soap of acetic acid with a soap Soap of palmitic acid, this mixture preferably being at least about 50 percent by weight of the Soap that contains acetic acid.

It has been found that using alkali or alkaline earth soap instead of aluminum soap while maintaining the other conditions, the grease is somewhat softer. This results in, that the amount of soap required to produce a fat with a certain consistency when used · an alkali or alkaline earth soap is higher than that of aluminum soap; the latter is therefore more economical and is preferred for this reason.

Any mineral, aromatic or naphthenic oil can be used as the lubricating oil, with a highly naphthenic oil is preferred for the production of lubricating greases with a high heat resistance will. Synthetic lubricating oils can also be used, e.g. B. esters of sebacic or adipic acid and from alcohols having about 6 to ^ carbon atoms, such as 2-ethylhexanoI. It won't more than about 60% oil, mostly between about 10 and 50% based on the weight of the grease used. In general, the consistency of the Grease when the amount of oil decreases. It is also advantageous to use oils or mixtures of oils having a viscosity index between about 10 and 100 5 or even higher, preferably between about 30 and 70 to use.

The most commonly used linear polymer of butene or isobutylene is hydrogenated or unhydrogenated liquid homopolymer with a

ίο Average molecular weight of about 300 to 2500. This polymer can be the only oil-like constituent of the grease and can be used in an amount up to about 98 percent by weight. On the other hand, at least 25 percent by weight should be one Polymerisate used to create a lubricating grease with high consistency, durability and performance to manufacture. Mixtures of the polymers can also be used, namely a mixture au. ·· with two or more such polymers

ao a different molecular weight or a Mixture of non-hydrogenated and hydrogenated polymers.

In the production of the lubricating greases according to the invention, about 2 to 15% aluminum soap, based on the weight of the grease, is dispersed in about half the required amount of polybutene or polyisobutylene, ie in about 10 to 50 percent by weight of the polymer. This dispersion is successful! with constant stirring at a temperature of about 10 to 50 C. The mixture obtained is increasingly heated, and when it has reached the temperature of about 110 ^° C., any oil used is added. Thereafter, when the temperature has reached about 150 to 180 C, the remaining amount of the required polymer is gradually added with stirring, the temperature being maintained between about 150 and 180 ⁰ C. As already mentioned above, the latter polymer can be different from that in the first stage of the process.

Then the mixture is cooled, and when it reaches room temperature it is placed in a Colloid mill or other suitable homogenization device homogenized.

Other ingredients can also be added to the grease, e.g. B. extreme pressure additives, anti-corrosion agents. Dyes, polymers with a high molecular weight, which the adhesion or binding ability of the fat z. B. improve on metal surfaces, such as polyisobutylene with a molecular weight of more than about 100,000; the amount of this add-on center! is generally not more than 2 to 3 percent by weight of the grease.

It has also been found that the lubricating greases according to the invention have lower amounts of aluminum soap needed as a thickener and an additive to improve adhesion than with the known lubricating greases in order to achieve the same result.

The components of the lubricating grease according to the invention, that is to say the aluminum soap, the polymer of Cj-monoolefin and the possibly added lubricating oil, form unique mixtures with special properties when they are used in the proportions given above. If this polymer is replaced by another homologue or this soap, this has a negative effect on the quality of the lubricating grease.
The following examples serve to explain

modification of the invention. In these examples the 5.0 weight percent aluminum stearate,

the following tests mentioned: 0.2 percent by weight additive for improvement the adhesiveness.

ASTMD217-52T or penetration test, which the

Consistency and the mechanical resistance of the ⁵ ^. _,. , ...,

Grease is measured. ^This grease was pliable, homogeneous,

ASTM 2266 for testing anti-wear properties!? _o ^{rbIos "ηά mh" nd} ^? T ^Pen etrationsindex of

ten of lubricating greases (4-ball method, 1800 rpm, ^{289 and} a wear index of 0.63.

1 hour, 75 ° C and 40 kg / cm ² ). ^For comparison, a lubricating grease was produced

ίο which was also free of mineral oils, but lithium soap instead of aluminum soap. Even at

Example 1 Use of 12 weight percent lithium soap

this grease was less harsh, the penetration

5 parts by weight of aluminum stearate and 42 parts by weight was 319.

share non-hydrogenated polyisobutylene with an average of 15

The average molecular weight of 460 at B is η ie 1 3
Mixed room temperature. The mixture was
then heated as quickly as possible while stirring.

When the temperature reached about 120 ° C, a grease similar to 20 parts naphthenic oil having a viscosity index of ao was prepared according to the procedure of Example 1, but with 39.8 Ge-70 added. The mixture was heated further, parts by weight of a hydrogenated polyisobutylene with and - when the temperature was 170 to 180 C an average molecular weight of 447 and rose - were 32.8 parts of non-hydrogenated poly- 35 parts by weight of a hydrogenated polyisobutylene lyisobutylene with an average Molecular weight with an average molecular weight of 633.
of 730 and 0.2 parts of polyisobutylene with an as. This grease had a slightly lower mean molecular weight of more than 100,000 resistance (penetration: 296), but the antiwear gradually added. During this addition properties were better (wear index: 0.68). the temperature was kept at about 175 ^r C, and

it was stirred. Then the hot grease was Example 4

placed in a cooling vessel. The cooled fat 3 °

was then poured into a blender and the procedure of Example 1 was repeated,

sent through a homogenizer. but using 74.8 parts by weight

The grease was pliable, tough, homogeneous, medium molecular weight polyisobutylene

weakly colored and transparent. The hardness was 500.

285 (in Vio ^mm be-i 25 ° C, see ASTM test 217-52T 35 The lubricating grease had a remarkable mechanical

with mechanically untreated grease and 297 niche resistance; the penetration was:
for grease treated with 60 strokes.

The wear index (ASTM test 2266) was 0 _{72.294 for mechanically} untreated grease,

A comparison showed that for a grease which

no polyisobutylene with a low molecular weight _mechanically treated grease (60 hits), a greater amount of aluminum soap (8 wt% instead of 5%) to achieve the same degree of hardness and a greater amount of anti-wear properties to improve the adhesive noticeable; the wear index was 0.70.
ability (1 weight percent instead of 0.2%) 45

was needed. On the other hand, this example was 5
Grease containing 8 percent by weight aluminum soap,

1% polyisobutylene having a molecular weight of The procedure of Example 1 was repeated,

contained more than 100,000 and 91% mineral oil, the mineral oil being replaced by a synthetic oil

Wear index 1.07. 5 ° (Di-2-äthylhexyIsebazinsäureestor) was replaced.

From this it is clear that du.-ch use The grease also possessed remarkable

of polyisobutylene with a molecular weight of anti-wear properties (wear index 0.70),

less than 2500 in the production of the grease but a slightly lower consistency (penetration:

smaller amounts of thickeners and additives 340).

mediums are needed, but grease 55

better lubricating and anti-sealing properties Examples 6 to 9
owns.

Four naphthenic mineral greases were

_. I ₇ ° 'en (viscosity index: 70), non-hydrogenated polyiso-

0 e 1 s ρ 1 e _{6o but} y] _en> aluminum soap and an additive for

_ j - ο ...... "Improvement of the adhesion (polyisobutylene with

There was prepared a grease of: _{a Miu} f _{older M} otekulargewidit of more than

46.8 percent by weight of non-hydrogenated polyiso 100,000).

butylene with an average molecular weight The respective weight ratios of these compo-

of 460, 65 nents in fats and the test results are in

48.0 percent by weight of non-hydrogenated polyiso- listed in the table below.

butylene with an average molecular weight The molecular weight of the polymer used

from 730. sats is aneeeehen after the abbreviation PlB.

Examples 6

PIB 300 34 72.8 71.8 33 PIB 670 8th 5 41.8 Al stearate 7th 3 Al acetopalmitate 57.8 20th 20th 5 mineral oil 0.2 0.2 0.2 20th Adhesion improver 301 287 285 0.2 Penetration (untreated fat) 0.74 0.71 0.72 304 Wear index 0.68

The main characteristics of these greases are their consistency and anti-wear properties.

For comparison, a grease was made up of 54.8 percent by weight mineral lubricating oil, 5 percent by weight Aluminum stearate, 10 weight percent polyisobutylene with an average molecular weight of 670 and 30 weight percent polyisobutylene with an average molecular weight of 3500 produced. As a result the addition of the last-named polymer made it difficult to process the fat at low temperatures or apply mechanically. The same disadvantage had greases that contain polyethylene with a low Molecular weight and polyhexane included.

On the other hand, suitable greases cannot be made from high molecular weight polyolefins weight can be produced.

The same grease was produced as in Example ι, but using calcium stearate instead of aluminum stearate. This grease had a much lower consistency

These results clearly show that the fiction, contemporary greases due to the use de; Above specified components in certain Men gene ratios be greatly improved properties sit.

109538/3 »

Claims (4)

Patent claims: 1. Lubricating grease, consisting of a) 2 to 15 percent by weight aluminum soap, b) 25 to 98 percent by weight hydrogenated or non-hydrogenated polybutene or polyisobutene with an average molecular weight of 300 to 2500 and c) 0 to 60 weight percent lubricating oil carrier. 2. Lubricating grease according to claim 1, consisting of a) 3 to 8 percent by weight aluminum soap, b) 35 to 97 percent by weight hydrogenated or non-hydrogenated polybutene or polyisobutylene with an average molecular weight of 300 to 2500 and c) 0 to 57 percent by weight of lubricant carrier. 3. Lubricating grease according to claim 1 and 2, characterized in that it is the aluminum soap Contains carboxylic acid with 12 to 20 carbon atoms. 4. A process for the production of lubricating greases according to claims 1 to 3, characterized in that 2 to 15 percent by weight of aluminum soap, based on the weight of the composition, in 10 to 50 percent by weight of a polymer of hydrogenated and non-hydrogenated polybutene and polyisobutylene with an average Dispersed molecular weight of 300 to 2500 at a temperature of about 15 to 50 ⁰ C, the dispersion obtained gradually heated and her 0 to 60 percent by weight lubricating oil carrier, as soon as a temperature of about 90 to 110 ° C is reached that you 15 to 48 percent by weight a hydrogenated and non-hydrogenated polybutene and polyisobutylene with an average molecular weight of 300 to 2500 is added as soon as the temperature, which is kept at the same level during the entire addition of the polymer, has reached about 150 to 180 "C, that this mixture is cooled and it Homogenized at about 10 to 35 ° C.