Patent Application
20140200169
The invention relates to novel high-temperature oils based on aromatic esters such as trimellitic esters, pyromellitic esters, trimesic esters or a mixture, or derivatives of phloroglucinol such as phloroglucinol trioctanoate, phloroglucinol tridecanoate and phloroglucinol tridodecanoate thereof, and a fully hydrogenated or a hydrogenated polyisobutylene or a mixture thereof.
High-temperature oils which are used in the field of industrial chain lubrication, for example in conveying systems, painting lines, the textile industry, the insulating materials industry, the glass industry, etc., and belt lubrication in continuous wood pressing plants, typically consist of a three-component system.
This three-component system generally consists of an aromatic ester, a synthetic hydrocarbon and a polymer based on polyisobutylene. The synthetic hydrocarbon is used as a solubilizer. Also added to this lubricant system are commercial additives. However, a disadvantage of these systems is that the use of the synthetic hydrocarbon limits the working temperature of the oil, since it vaporizes very rapidly at temperatures >200° C.
A three-component system is described, for example, in EP 1 154 011 B1. Here, a lubricant oil composition comprising an aromatic ester compound and, as a further base oil, an α-olefin oligomer, and also a polyisobutene, is provided.
As already stated above, the loss of performance for a three-component lubricant composition is high as a result of the vaporization of the solubilizer. The vaporization results in formation of a deposit or a residue formed from the remaining constituents of the lubricant on the application surface or the application area, as a result of which full lubrication can no longer be ensured. This deposit then has to be dissolved again. In general, operation has to be stopped and the residue has to be removed. There is thus a need for a high-temperature oil in which the vaporization of individual constituents of the oil is greatly reduced and hence the lubricity is not lost at constantly high temperature over a long period.
Such a high-temperature oil is especially required for chain and belt lubrication of wood presses, as present, for example, in Contipressen™ continuous presses for the production of laminate floors.
It was an object of the present invention to provide a high-temperature oil with which good lubricity is achieved at constantly high temperature over a long period and which can be provided in different viscosities according to the application.
This object is surprisingly achieved by the provision of a high-temperature oil which consists, as a two-component system an aromatic ester of the general formula (I)
where R1 is a linear or branched alkyl group having 6 to 16 carbon atoms and n is 3 or 4, or a compound of the general formula (II)
where R is a linear or branched alkyl group having a chain length of 8 to 16 carbon atoms and n is equal to 3,
and
a hydrogenated polyisobutylene, a fully hydrogenated polyisobutylene or a mixture of a fully hydrogenated and a hydrogenated polyisobutylene. Preferably, a fully hydrogenated polyisobutylene is included.
In general, the high-temperature oil comprises 40 to 91.9% by weight of the aromatic ester of the general formula (I) or of the compound of the general formula (II) and 50 to 5% by weight of the hydrogenated, fully hydrogenated polyisobutylene or of a mixture of hydrogenated and fully hydrogenated polyisobutylene.
In addition, the high-temperature oil may comprise 0.1 to 6% by weight, especially 2 to 5% by weight, of an antioxidant.
The high-temperature oil may also comprise 0 to 4% by weight, especially 0.3 to 3.5% by weight, of an antiwear agent, 0.1 to 1.0% by weight of an anticorrosive, and 0 to 2% by weight, especially 0.1 to 1.5% by weight, of an ionic liquid.
The ester compound of formula (I) present in the high-temperature oil is preferably selected from the group consisting of esters of trimellitic acid, pyromellitic acid, trimesic acid or mixtures thereof. The compound of the general formula (II) is a derivative of phloroglucinol (benzene-1,3,5-triol), preferably phloroglucinol trioctanoate, phloroglucinol tridecanoate and phloroglucinol tridodecanoate.
The antioxidant present in the high-temperature oil, which may contain sulfur and/or nitrogen and/or phosphorus in the molecule, is selected from the group consisting of aromatic aminic antioxidants such as alkylated phenyl-alpha-naphthylamine, dialkyldiphenylamine, sterically hindered phenols such as butylhydroxytoluene (BHT), phenolic antioxidants having thioether groups, zinc dialkyldithiophosphates or molybdenum dialkyldithiophosphates or tungsten dialkyldithiophosphates, and phosphites.
The antiwear agent present in the high-temperature oil is selected from the group consisting of antiwear additives based on diphenyl cresyl phosphate, amine-neutralized phosphates, alkylated and nonalkylated triaryl phosphates, alkylated and nonalkylated triaryl thiophosphates, zinc dialkyldithiophosphates or molybdenum dialkyldithiophosphates or tungsten dialkyldithiophosphates, carbamates, thiocarbamates, zinc dithiocarbamates or molybdenum dithiocarbamates or tungsten dithiocarbamates, dimercaptothiadiazole, calcium sulfonates and benzotriazole derivatives.
The anticorrosive present in the high-temperature oil is selected from the group consisting of additives based on “overbased” calcium sulfonates having a TBN of 100 to 300 mg KOH/g, amine-neutralized phosphates, alkylated calcium naphthalenesulfonates, oxazoline derivatives, imidazole derivatives, succinic monoesters, N-alkylated benzotriazoles.
The ionic liquid (IL) used in the high-temperature oil comprises what are called salt melts which, by definition, are liquid at temperatures below 100° C. Many ionic liquids are also liquid at room temperature or at lower temperatures. Suitable cations for ionic liquids have been found to be a quaternary ammonium cation, a phosphonium cation, an imidazolium cation, a pyridinium cation, a pyrazolium cation, an oxazolium cation, a pyrrolidinium cation, a guanidinium cation, a morpholinium cation or a triazolium cation, which may be combined with an anion selected from the group consisting of [PF6]−, [BF4]−, [CF3CO2]−, [CF3SO3]−. [(CF3SO2)2N]−, [(R4SO2) (R5SO2)N]−, [(CF3SO2) (CF3COO)N]−, [R4—SO3]−, [R4—O—SO3]−, [R4—COO]−, Cl−, Br−, [NO3]−, [N(CN)2]−, [HSO4]−, or [R4R5PO4]−, and the R4 and R5 radicals are each independently selected from hydrogen; linear or branched, saturated or unsaturated, aliphatic or alicyclic alkyl groups having 1 to 20 carbon atoms; heteroaryl groups, heteroaryl-C1-C6-alkyl groups having 3 to 8 carbon atoms in the heteroaryl radical and at least one heteroatom from N, O and S which may be substituted by at least one group selected from C1-C6-alkyl groups and/or halogen atoms; aryl groups, aryl-C1-C6-alkyl groups having 5 to 12 carbon atoms in the aryl radical, which may be substituted by at least one C1-C6-alkyl group, partly and fully fluorinated alkyl radicals. However, further combinations are also possible. Anions of [PF(6-x)R7x], [R7—SO3]− type are also known. R7 here represents partly or fully fluorinated radicals such as pentafluoroethyl or perfluorobutyl.
The following anion type is likewise quite thermally stable: (FSO2)2N.
In order to display positive action in oils, the ionic liquids should firstly show solubility in the oils, although complete miscibility is not absolutely necessary. The ionic liquids should be thermally stable and not promote corrosion, for example by forming reaction products which are noncorrosive or corrosive only in a very delayed manner in the presence of water.
Particularly advantageous ionic liquids have been found to be those such as tetraalkylammonium bis(trifluoromethylsulfonyl)imides and tetraalkylphosphonium bis(trifluoromethylsulfonyl)imides, for example trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)imide (HPDimide) and methyltrioctylammonium bis(trifluoromethylsulfonyl)imide (Moimide). Ionic liquids which have likewise been found to be particularly advantageous are those such as tetraalkylammonium tris(perfluoroethyl)trifluorophosphate and tetraalkylphosphonium tris(perfluoroethyl)trifluorophosphate, for example tetrabutylphosphonium tris(perfluoroethyl)trifluorophosphate (BuPPFET), trihexyl(tetradecyl) tris(perfluoroethyl)trifluorophosphate (HDPPFET). It has likewise been found that pyrrolidinium tris(perfluoroethyl)trifluorophosphates are particularly advantageous. Also particularly advantageous are tetraalkylammonium perfluorobutanesulfonates and tetraalkylphosphonium perfluorobutanesulfonates such as trihexyl(tetradecyl)phosphonium perfluorobutanesulfonate (HDPnonaflate).
It is also possible to use any desired mixtures of the ionic liquids.
The inventive two-component system has a much higher performance in terms of thermal stability and residue formation or residue characteristics. The enormous rise in thermal stability is manifested particularly in a distinct increase in lubrication characteristics. The relubrication intervals were extended and an energy saving of up to a 30% power saving was achieved.
As already mentioned, the formation of residues is distinctly reduced. As a result, the formation of cracking residues is also reduced and the residues formed can be very easily dissolved with fresh oil.
The appended figures show the advantages of the inventive high-temperature oil based on two components.
The invention is now illustrated in detail by the examples which follow.
Production of an inventive two-component high-temperature oil
Composition of the high-temperature oil:
63.4% by weight of aromatic trimellitic ester
30.0% by weight of fully hydrogenated polyisobutylene
3.5% by weight of antiwear agent
3.0% by weight of antioxidant
0.1% by weight of anticorrosive
As the aromatic ester, trimellitic ester is initially charged in a stirred tank. At 100° C., the polyisobutylene is added while stirring. Subsequently, the mixture is stirred for one 1 hour in order to obtain a homogeneous mixture. The antiwear agent and the antioxidant are added to the tank at 60° C. while stirring. After about 1 hour, the finished oil can be dispensed into the containers provided.
Production of a known three-component high-temperature oil
Composition of the high-temperature oil:
47.4% by weight of aromatic trimellitic ester
16.0% by weight of polyisobutylene
30.0% by weight of synthetic hydrocarbon
3.5% by weight of antiwear agent
3.0% by weight of antioxidant
0.1% by weight of anticorrosive
As the aromatic ester, trimellitic ester is initially charged in a stirred tank together with the poly-α-olefin as the synthetic hydrocarbon. At 100° C., the polyisobutylene is added while stirring. Subsequently, the mixture is stirred for 1 hour in order to obtain a homogeneous mixture. The antiwear agent and the antioxidant are added to the tank at 60° C. while stirring. After about 1 hour, the finished oil can be dispensed into the containers provided.
The advantages of the inventive high-temperature oil are shown hereinafter.
The base data for the oil according to example 1 and comparative example 1 are shown in table 1.
1.1. Thermal Stability Studies
Studies were conducted with regard to vaporization and viscosity under thermal stress on a starting weight of 5 g in an aluminum pan at 230° C. For this purpose, the oils according to example 1 and comparative example 1 were compared with one another.
The above results show that the use of fully hydrogenated polyisobutylene in a two-component high-temperature oil can distinctly reduce the rise in viscosity and in the vaporization loss compared to the known three-component oil. These results are also shown in the form of graphs in
1.2. Comparison of the Friction Values
The oils produced in example 1 and comparative example 1 were used for determination of the friction values. For this purpose, an oscillating frictional wear test (SRV) was conducted based on DIN 51834, ball/disk test condition, load 250 N, 50° C. to 250° C., stroke 1 mm, 50 Hz, 165 min. The results are shown in table 3.
These results, which are also shown in
1.3. Residue Characteristics After Complete Vaporization of the Oil at 250° C.
The formation of residues and the behavior of the residues with regard to solubility were studied.
The oil to be tested is weighed to 5 g onto a steel sheet which has been bent to size and cleaned with solvent beforehand, and then vaporized off at 250° C. in an air circulation drying cabinet for min. 72 h. The square sheet is bent manually on all four sides, so as to give a dish shape.
After cooling, the results of the re-weighing are documented.
Important features for this test are the determination of the dissolvability of the residue surface with fresh oil and the amount of residue formed. For this purpose, a drop of the fresh oil is applied to the residue and rubbed in gently by means of a rounded glass rod with circular movements.
The results show that the inventive high-temperature oil forms a lower level of residue at 4.8% than the known oil, which has a residue of 6.0%. The residue formed from the inventive high-temperature oil has very good surface dissolvability, which means that these residues are easy to dissolve with fresh oil. In contrast, the residue of the known oil has much poorer surface redissolvability with fresh oil.
1.4. High-Performance Chain Test Bed
Temperature: 220° C.
Speed: 2 m/sec
Load: 2600 N
Run time after 0.1% chain lengthening 22 hours for example 1, and 17 hours for comparative example 1.
Before the test, the chain is immersed into the lubricant oil to be tested. After the immersion, the chain is suspended, such that the excess lubricant can drip off. Subsequently, the chain is installed into the chain test bed (see
The run time is fixed at a chain lengthening of 0.1%. The lengthening of the chain arises through wear at the chain members during the test run.
Composition of the inventive high-temperature oil:
82% by weight of aromatic trimellitic ester
12.7% by weight of fully hydrogenated polyisobutylene
0.3% by weight of antiwear agent
4.5% by weight of antioxidant
0.5% by weight of anticorrosive
The production is effected as described in example 1.
Composition of the three-component high-temperature oil:
55.7% by weight of aromatic trimellitic ester
7% by weight of polyisobutylene
33.20% by weight of synthetic hydrocarbon
0.30% by weight of antiwear agent
3.7% by weight of antioxidant
0.10% by weight of anticorrosive
The production is effected as described in comparative example 1.
The advantages of the inventive high-temperature oil are shown hereinafter.
The base data for the oil according to example 2 and comparative example 2 are shown in table 4.
2.1. Thermal Stability Studies
Studies were conducted with regard to the vaporization and viscosity under thermal stress on a starting weight of 5 g in an aluminum pan at 230° C. For this purpose, the oils according to example 2 and comparative example 2 were compared with one another.
The above results show that the use of fully hydrogenated polyisobutylene in a two-component high-temperature oil can distinctly reduce the rise in viscosity and in the vaporization loss compared to the known three-component oil. These results are also shown as graphs in
2.2. Comparison of the Friction Values
The oils produced in example 2 and comparative example 2 were used to determine the friction values. For this purpose, an oscillating frictional wear test (SRV) was conducted based on DIN 51834, ball/disk test condition, load 250 N, 50° C. to 250° C., stroke 1 mm, 50 Hz, 165 min.
The results are shown in table 6.
These results, which are also shown in
2.3. Residue Characteristics after Complete Vaporization of the Oil at 250° C.
The formation of residues and the behavior of the residues in terms of solubility were studied. The method is described in example 1.
Both the inventive high-temperature oil and the known oil had a residue of 3.0%; the residue formed from the inventive high-temperature oil had very good surface dissolvability, which means that these residues can be dissolved easily with fresh oil. In contrast, the residue of the known oil has much poorer surface redissolvability with fresh oil.
2.4. High-Performance Chain Test Bed
The test on the high-performance chain test bed was conducted at 220° C., a speed of 2.0 m/sec and a load of 2600 N. The run time after chain lengthening 0.1% is 19 h for example 2, and that for comparative example 2 is 17 h.
The test was conducted as described in example 1.
Composition of the Inventive High-Temperature Oil:
45.4% by weight of aromatic trimellitic ester
48.00% by weight of fully hydrogenated polyisobutylene
2.5% by weight of antiwear agent
3.0% by weight of antioxidant
0.1% by weight of anticorrosive
The production was effected as described in example 1.
Composition of the Three-Component High-Temperature Oil:
47.0% by weight of aromatic trimellitic ester
17.4% by weight of polyisobutylene
29.0% by weight of synthetic hydrocarbon
3.5% by weight of antiwear agent
3.0% by weight of antioxidant
0.10% by weight of anticorrosive
The production was effected as described in comparative example 1.
The advantages of the inventive high-temperature oil are shown hereinafter.
The base data for the oil according to example 3 and comparative example 3 are shown in table 7.
3.1. Thermal Stability Studies
Studies were conducted with regard to vaporization and viscosity under thermal stress on a starting weight of 5 g in an aluminum pan at 230° C. For this purpose, the oils according to example 3 and comparative example 3 were compared with one another.
The above results show that the use of fully hydrogenated polyisobutylene in a two-component high-temperature oil can reduce the rise in viscosity and in the vaporization loss compared to the known three-component oil. These results are also shown as graphs in
3.2. Comparison of the Friction Values
The oils produced in example 3 and comparative example 3 were used to determine the friction values. For this purpose, an oscillating frictional wear test (SRV) was conducted based on DIN 51834, ball/disk test condition, load 250 N, 50° C. to 250° C., stroke 1 mm, 50 Hz, 165 min.
The results are shown in table 9.
These results, which are also shown in
3.3. Residue Characteristics After Complete Vaporization of the Oil at 250° C.
The formation of residues and the behavior of the residues in terms of solubility were studied. The test was conducted as described in example 1.
The results show that the inventive high-temperature oil forms a lower level of residues at 4.8% than the known oil, which has a residue of 11.8%. The residue formed from the inventive high-temperature oil has very good surface dissolvability, which means that these residues can be dissolved easily with fresh oil. In contrast, the residue of the known oil has much poorer surface redissolvability with fresh oil.
3.4. High-Performance Chain Test Bed
The test on the high-performance chain test bed was conducted at 220° C., a speed of 2.0 m/sec and a load of 2600 N. The run time after chain lengthening 0.1% was 17 h for example 3 and 15 h for comparative example 3. The test was conducted as described in example 1.
Composition of the Inventive High-Temperature Oil:
62.90% by weight of aromatic trimellitic ester
30.00% by weight of fully hydrogenated polyisobutylene
3.5% by weight of antiwear agent
3.0% by weight of antioxidant
0.1% by weight of anticorrosive
0.50% by weight of ionic liquid
The production was effected as described in example 1.
The ionic liquid used was HDP imide (=trihexyl(tetradey-phosphonium bis(trifluoromethylsulfonyl)imide).
Composition of the inventive high-temperature oil:
63.40% by weight of aromatic trimellitic ester
30.00% by weight of fully hydrogenated polyisobutylene
3.5% by weight of antiwear agent
3.0% by weight of antioxidant
0.1% by weight of anticorrosive
The production was effected as described in example 1.
The base data for the oil according to example 4 and comparative example 4 are shown in table 10.
4.1. Thermal Stability Studies
Studies were conducted with regard to the vaporization and viscosity under thermal stress on a starting weight of 5 g in a closed aluminum pan at 250° C. The vaporization loss after 72 h/250° C. was 19%. The increase in apparent dynamic viscosity in mPas after 72 h/250° C. was 2300 mPas.
The above results show that the use of HDP imide can once again significantly improve the thermal stability of a two-component system. These results are also shown as graphs in
Composition of the Inventive High-Temperature Oil:
63.5% phloroglucinol tridecanoate
30.0% fully hydrogenated polyisobutylene
3.5% antiwear agent
3.0% antioxidant
0.1% by weight of anticorrosive
The production was effected as described in example 1.
It was also possible to obtain the results described in detail above with the high-temperature oil based on a derivative of phloroglucinol.
The above experimental results show that the inventive high-temperature oil in all studies conducted gave much better values than in the case of the known high-temperature oils.
In summary, it can be stated that the inventive two-component system has much higher performance with regard to thermal stability and residue formation or residue characteristics. The enormous rise in thermal stability is manifested particularly in a distinct rise in lubrication characteristics. The relubrication intervals were extended and an energy saving of up to a 30% power saving was achieved.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2011 102 540.9 | May 2011 | DE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/EP2012/002172 | 5/22/2012 | WO | 00 | 2/19/2014 |
