DE2257638B2 - GREASES - Google Patents

Description

20th

25th

The invention relates to lubricating greases which are thickened with polymers, in particular with polyolefins.

It is known to use lubricating oils using certain polyethylenes either alone or in admixture with other thickeners ^ for example alkali metal soaps, to thicken, as in the British Patent 9 86 192.

However, it has been shown that greases thickened with polyethylene have a "granular" structure, which is very difficult to convert to a smooth grease, and that better greases through use a mixture of olefin polymers can be formed.

According to DT-AS 1014 694 were already Mixtures of different polyethylenes are used as thickeners, and DT-AS 1 054 632 describes the use of a polypropylene produced by a special process, but which is insoluble in oil and is crystalline and also does not result in an easily smoothable grease. This is also true for the lubricating greases that are described in DT-AS 12 78 056 and in addition to a mandatory one further thickening agents and optionally a fatty acid metal soap either oil-soluble atactic polypropylene or an oil-soluble atactic ethylene-propylene copolymer while DT-OS 17 94 111 deals primarily with the selection of special particle diameters for polyolefins used in lubricating greases.

Surprisingly, it has now been found that the simultaneous use of two particularly selected polymers with special properties lubricating greases can be obtained differ advantageously from the previously known lubricating greases in that they can be smoothed very easily and have no granular structure.

The invention thus relates to lubricating greases made from a lubricating oil base oil thickened with olefin polymers, which are characterized in that, as ⁽ 15 olefin polymers, they are a mixture of an atactic polypropylene with a melt index above 50 and a polyethylene with a density of more than 94 g / cm ¹ contain, the weight ratio of auiktischem polyppropylene to polyethylene is 1:] to 10: 1.

The polymers with lower molecular weight, however, form lubricating greases with a smoother structure or Lubricating greases that can be smoothed out more easily, so dalj the choice of polymer will normally depend on the intended use of the grease. For general-purpose greases, e.g. greases for the lubrication of closed gears, however, a lower polymer content is preferred.

The melt index of polypropylene is above 50. In atactic polypropylene, the amount is present isotactic polypropylene preferably below 10%. The melt index of the polypropylene can according to the Test method BS 2782, method 105 C or ASTM D 123 B can be determined. The molecular weight of the polypropylene is preferably less than 100,000.

The polyethylene preferably has a molecular weight (Weight average) from 20,000 to 500,000, in particular 50,000 to 250,000. The total weight Polymer in the lubricating grease is 1 to 20%, in particular 3 to 15%, based on the total weight of the grease.

The weight ratio of atactic polypropylene to polyethylene is in the range from 1: 1 to 10: 1, in particular in the range from 2: 1 to 5: 1.

The lubricating greases according to the invention preferably have a penetration above 300, in particular a penetration of 310 to 500. The penetration of the lubricating grease can be determined according to the test method ASTM 217-68 can be measured.

example

Greases were prepared from two different lubricating oil base stocks as follows: the half of the total amount of the oil and the polyethylene were heated to 100 ⁰ C. Then, the atactic polypropylene was added slowly while heating to 150 ⁰ C. The batch was held at 150 ° C. for one hour to allow the polymers to swell and partially dissolve. The batch was heated to 18O ⁰ C and held for at least 30 minutes at this temperature, the polymers were completely dissolved. The remainder of the lubricating oil was added and the batch was cooled as quickly as possible to form the lubricating grease. The grease was circulated through a homogenizer at 80 ° C. and thereby smoothed.

In Tables 1 and 2, the starting materials are given, which are used for the production of those mentioned in Table 3 Greases have been used. Table 4 shows the influence of the melt index on the structure of the grease.

In the tables, "smooth" means an essentially homogeneous grease with a smooth consistency. "Grainy" means the presence of grains or particles in the grease, and by "rubbery" a structure is to be understood that is tougher and spongy or more elastic than the known one Most greases have a "buttery" structure. Furthermore, when part of such a Grease is made up of the main mass of threads that are still related to the main mass of grease and have elastic properties.

Table 1

Characteristic number of the polymers

Polymer quality Melt density Molecular type index g / ml weight

Atactic

Polypropylene B 0-20
20-50
<50

Polyethylene
II
III
IV

XGR 369 type 9
Type 50

0-20 20-50 <50

0.9 5

0.87 0.87 0.87

0.96 0.96 0.96

9000/10000 (iso-tactical share about 6%)

150000 88000 70000

Melt index: US 2782, method 1050 door polyethylene; ASTM D 1238 for polypropylene at 190 ° C Molecular weight: Intrinsic Viscosity-Method density: BS 2782, method 5Ο9Λ

Table 2

Key figure of the lubricating oils

Oil Kinematic Toughness, cS

37.8 ¹ C, 60'C 99 ¹ C

1077
137.2

242.6 40.49

41.33 10.27

Viscosity index

76 43

Table 3

Key figures for lubricating greases made from atactic polypropylene B (melt index > 50)

Fat- Oil- Atak Poly Oil type Atactic Total- Poly- WaIk- 1 1 411 structure Remarks I evening reu slightly rubbery oezeichen- Type table ethylene Type B poly propy- pene- 1 Fat can be smoothed out likewise tion Poly meri- len / poly- 1 1 441 will propy Smelting sate iithylen- tion 1 1 442 len (B), dex area Relationship 1 1 436 Wt% Type% by weight Y 0-20 Wt% nis 1 1 445 4/1663 Y 4.20 II 0.80 0-20 5.00 5.25: 1 4011 slightly grainy, light Ι Fat can be smoothed 20-50 1 4101 rubbery I will 4 / 1663A 3.93 II 0.75 4.68 5.25: : 1 473 y likewise I slightly rubbery 4/1661 Y 4.20 III 0.80 > 50 5.00 5.25: : 1 372 slightly grainy Fat can be smoothed out 4/1660 Y 4.20 IV 0.80 > 50 5.00 5.25: 411 smooth 4 / 1660A 3.93 IV 0.75 4.68 5.25: 443 smooth 1/1739 Z 9.98 II 1.98 11.96 5 Polypropylene 420 grainy, ) Fat can be smoothed 4/1668 7.43 II 1.48 8.91 5 431 slightly rubber > still 4 / 1668A 5.81 II 1.16 6.97 5 401 good J light, rubbery 4/1669 Z 8.75 III 1.75 10.50 5 422 smooth 1 fat can be with some 4 / 1669A 7.66 III 1.53 9.19 5 smooth I smoothed difficulty 4 / 1669B 7.17 III 1.43 8.60 5 Wt% smooth J will be 1/1751 Z 10.01 IV 1.98 11.99 5 slightly grainy 4/1667 8.75 IV 0.75 10.50 5 5.50 slightly grainy 1/1778 7.53 IV 3.67 11.00 2 4.40 slightly grainy 1/1769 6.67 IV 3.33 10.00 2 5.50 slightly grainy Table 4 Influence of the melt index 5.50 Fat is easy to get description 7.20 Walkpene structure smooth of the lubricant tration fat Remarks 4/1629 373 4 / 1629A 436 4/1630 436 4/1631 443 grainy, rubbery] very difficult to 438 likewise slightly grainy, rubbery

-L

continuation Öliyp Arctic
Type H l ^J olyprt: pylcn Wiilkpcne-
(ralio ii structure Ucincrkiinyun of the Schmicr-
l'cMcs Schmcl / in- CicW .-% doxious Z 0-20 15.00 173 very grainy, extremely difficult 4/1633 rubbery fat to be smoothed 0-20 9.40 364 likewise 4 / 1633A 20-50 15.00 398 slightly grainy. Fat goes with 4/1634 rubbery some difficult smooth. 20-50 11.30 440 likewise 4 / I634A > 50 15.00 420 slightly rubbery Fat can be smoothed out 4/1635 > 50 12.00 428 likewise 4/1454

Claims (3)

Patent claims: :. Lubricating greases made from a lubricating oil base oil thickened with olefin polymers, characterized in that they contain, as olefin polymers, a mixture of an atactic polypropylene with a melting index of over 50 and a polyethylene with a density of more than 0.94 g / cm ^J , the weight ratio being atactic Polypropylene to polyethylene is 1: 1 to 10: 1. 2. Lubricating greases with a penetration of 310 to 500, according to claim I. 3. Lubricating greases according to claim 1 or 2, characterized in that they are an ataktiiiches polypropylene with a molecular weight of less than 100,000.