CA1285549C - Use of a fluid perfluoropolyether, having a very high viscosity, as a lubricant - Google Patents
Use of a fluid perfluoropolyether, having a very high viscosity, as a lubricantInfo
- Publication number
- CA1285549C CA1285549C CA000536351A CA536351A CA1285549C CA 1285549 C CA1285549 C CA 1285549C CA 000536351 A CA000536351 A CA 000536351A CA 536351 A CA536351 A CA 536351A CA 1285549 C CA1285549 C CA 1285549C
- Authority
- CA
- Canada
- Prior art keywords
- viscosity
- perfluoropolyether
- grease
- cst
- fluid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M169/00—Lubricating compositions characterised by containing as components a mixture of at least two types of ingredient selected from base-materials, thickeners or additives, covered by the preceding groups, each of these compounds being essential
- C10M169/02—Mixtures of base-materials and thickeners
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M107/00—Lubricating compositions characterised by the base-material being a macromolecular compound
- C10M107/38—Lubricating compositions characterised by the base-material being a macromolecular compound containing halogen
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M119/00—Lubricating compositions characterised by the thickener being a macromolecular compound
- C10M119/22—Lubricating compositions characterised by the thickener being a macromolecular compound containing halogen
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2211/00—Organic non-macromolecular compounds containing halogen as ingredients in lubricant compositions
- C10M2211/06—Perfluorinated compounds
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2213/00—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2213/00—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
- C10M2213/02—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions obtained from monomers containing carbon, hydrogen and halogen only
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2213/00—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
- C10M2213/02—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions obtained from monomers containing carbon, hydrogen and halogen only
- C10M2213/023—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions obtained from monomers containing carbon, hydrogen and halogen only used as base material
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2213/00—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
- C10M2213/04—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions obtained from monomers containing carbon, hydrogen, halogen and oxygen
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2213/00—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
- C10M2213/04—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions obtained from monomers containing carbon, hydrogen, halogen and oxygen
- C10M2213/043—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions obtained from monomers containing carbon, hydrogen, halogen and oxygen used as base material
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2213/00—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
- C10M2213/06—Perfluoro polymers
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2213/00—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
- C10M2213/06—Perfluoro polymers
- C10M2213/0606—Perfluoro polymers used as base material
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2213/00—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
- C10M2213/06—Perfluoro polymers
- C10M2213/062—Polytetrafluoroethylene [PTFE]
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2213/00—Organic macromolecular compounds containing halogen as ingredients in lubricant compositions
- C10M2213/06—Perfluoro polymers
- C10M2213/062—Polytetrafluoroethylene [PTFE]
- C10M2213/0623—Polytetrafluoroethylene [PTFE] used as base material
Abstract
"USE OF A FLUID PERFLUOROPOLYETHER HAVING A VERY
HIGH VISCOSITY, AS A LUBRICANT".
A B S T R A C T
Use as the basic component of lubricating oils and greases, of a fluid perfluoropolyether, with linear structure, having a kinematic viscosity at 20°C not lower than 8,000 cSt, and constituted by sequences of perfluorooxyalkylene units selected from -CF2CF2O-, -CF20, -CF2CF2CF2O- units.
HIGH VISCOSITY, AS A LUBRICANT".
A B S T R A C T
Use as the basic component of lubricating oils and greases, of a fluid perfluoropolyether, with linear structure, having a kinematic viscosity at 20°C not lower than 8,000 cSt, and constituted by sequences of perfluorooxyalkylene units selected from -CF2CF2O-, -CF20, -CF2CF2CF2O- units.
Description
5~
BACKGR UND OF THE INYENTION
The object of the invention is the use of fluid perfluoropolyethers having a very high kinematic viscosity, comprised within the range of from 8,000 cSt to 40,000 cSt at 20C, and preferably of at least 10,000 cSt, as lubricating oils, and as the basic components of perfluo-rinated lubricating greases.
The use is well-known of fluid perfluoropoly-ethers, of neutral type, as lubricating oils endowed with high performance characteristics relating to the resistance to the atmospheric and chemical agents in general, even at high temperatures.
The products presently available from the market, suitable for use as lubricants, are low- or medium viscosity oils, with maximum viscosity values of the order of 2,000 cSt at 20C.
/
~?~ 54~1 THE PRESENT INVENTION
It has been surprisingly found now that the perfluoropolyethers having such a high kinematic viscosity as indicated above, show surprisingly improved charact~ristics of use, as lubricants, than the lower viscosity perfluoropolyethers used up to date.
The improvement in some specific properties is not attributal~ simply to the high viscosity of the product, and should be regarded as unforeseeable.
The perfluoropolyethers according to the invention, having viscosity values comprised within the above specified range, are constituted by linear chains of oxyperfluoroalkylene units selected from the following units:
-CF2CF20-, -CF20-, -CF2CF2CF20- .
The chain end groups are of perfluorinated neutral type.
In particular, the products belonging to the following classes are suitable:
.
1) R~FO(CF2cF2O)m(cF2o)n f wherein Rf and R'f, equal to, or different from each other, are either -CF3 or -C2F5, the perfluorooxy-alkylene units being randomly distributed along the chain, and indices _, n are such integers that the viscosity (which is a function of the average molecular weight) is within the indicated ranges. Products of .~
~855~
this type are disclosed in U.S. patent No. 3,665,041 and are known on the market under the trade name "Fomblin z(R),,;
5 2 ) R ' f(CF2CF2)pRf wherein Rf and R'f, equal LO, or different from each other, are either -CF3 or -C2F5 and index p is such an integer that the viscosity falls within the above indicated limits. Products of this type are disclosed in U.S. patent No. 4,523,039;
3) R'fO(CF2CF2CF2O)SRf wherein Rf and R'f, equal to, or different from each 3~ or -C2F5 or -C3F7, and index s is an integer such that the viscosity is comprised within the above indicated ranges. Products of this type are disclosed in European patent No 0 148 482.
On considering the very high viscosity of the products, and that such a viscosity, because of their linear structure, varies to a considerably low degree with varying temperature, as well as their very low volatility, the products of the invention can be advantageously used as lubricants for high temperatures.
It is known that a relationship exists which allows the friction coefficient ~ to be expressed as a function of Stribeck number ~N/P, wherein ~ = dynamic viscosity N = revolution speed: P = applied load per surface unit. Such a relationship, reported on a diagram allows the areas to be evidenced in which the system works under boundary lubrication, mixed lubrication and ,, ~85i~i~9 elastohydrodynamic lubrication conditions; on this regard, reference is made to "Lubricants", by D. Klamann (Verlag Chemie 1984), pages 33-foll..
The perfluoropolyether according to the present invention shows a surprising and unexpected improvement as relates to the wear rate under "mixed" lubrication conditions, as compared to the up to date commonly used perfluoropolyethers, having a much lower viscosity. This improvement cannot be simply explained by taking into account the difference in viscosity; it could be thought as being in some way connected with the molecular structure of the product.
The equipment used for measuring the wear rate is essentially constituted by a pin-on-rig system, consisting of a carbon steel (c 15) pin resting, for a surface area of 12 mm2, on the cylindrical surface, revolving at a rate of 350 rpm, of a specimen of the same material, having an average surface roughness of 0.15 microns, and a diameter of ~5 mm. The pin is loaded with a weight of 15 kg.
~ The procedure used in the test was as follows.
The specimens and the pins are cleaned in 1,1,2-trichloro-2,2,1-trifluoroethane, let dry and weighed. The specimen is assembled on the equipment in such a way that it can dip inside a tray containing the lubricating oil. After 1,000 revolutions, the specimen is dr~wn from the equipment, is cleaned in 1,1,2-trichloro-2,2,1-trifluoroethane, let dry and weighed again, and is then assembled again on the equipment. The measurement is repeated after 10,000 rpm.
Then the difference in weight is computed relatively to the number of run metres (~W/L):
~ r r .2 !3S5~
Test Time Z 1600 Z 25 Z 03 (Minutes)~W/L (~/m) ~W/L (~/m~~/L (g/m) 3 O.lxlO 5 3xlO 53.1xlO 5 lxlO 5 2xlO 52.5xlO 5 Z 1600 Perfluoropolyether belonging to Class (1), a commercial product Fomblin(R) Z by Montedison, having a kinematic viscosity of 16,000 cSt at 20C.
Z 25 Ditto, with a viscosity of 250 cSt -Z 03 Ditto, with a viscosity of 30 cSt.
The difference in the values measured between the investigated products evidences a lower wear rate in the high-viscosity oil. Above all, the necessary times for wear to be obtained are much higher for the highest-viscosity oil.
The perfluoropolyethers of the invention are particularly fit for the formulation of perfluorinated greases endowed with enhanced characteristics as compared to analogous products manufactured from lower-viscosity perfluoropolyether oils. Because of the very low value of high-temperature oil separation which was observed (even at a much higher oil percentage in the grease, than in the products of the prior art), the novel grease type results particularly suitable for high temperature usesO
A very meaningful characterizing property of the new grease type formulated with the perfluoropolyether oil according to the invention is the low static friction coefficient (measured as the starting resistent torgue).
- 6 - :
The method of preparation of the greases according to the invention is similar to the method as reported in European patent application No. EP 0 095 825, with the difference that, because of the high viscosity of the perflu~ropolyether, the kneading and the following homogenizing have to be performed under high temperature conditions (70C).
The oil amounts used for formulating polytetrafluoroethylene (PTFE)-thickened greases vary within the range of from 60% to 90%.
EXAMPLE OF PREPARATION OF A PERFLUORINATED GREASE
-15Oil used is Fomblin(R) Z 1600, an above-mentioned product, having a kinematic viscosity of 16,000 cSt at 20C.
It is introduced in the percentage of 74.1% by weight, relatively to the grease.
The thickening agent is a granular PTFE (average particle diameter 4-5 ~m; m.w. 40,000), used in the percentage of 25.9% by weight, relatively to the grease.
25The kneading and homogenizing method is reported in the above-cited patent.
To comparative purposes, a perfluorinated grease was prepared by using the same PTFE type, and Fomblin(R) 30Z 25 oil, having a viscosity of 250 cSt.
The formulation comprises 68.5% by weight of Fomblin(R) 2 25 and 31.5% by weight of PTFE.
z-r ~35~
CHEMICAL-PHYSICAL CHARACTERIZATION
OF THE FORMULATED GREASE
With Fomblin With Fomblin Consistency Z 1600z 25 Macropenetration mm/10 (ASTM D 217) 283 286 Macropenetration after 10,000 double shots, mm/10 (ASTM
D 217) 270 298 Oil separation @204C/30 h (FTMS 791-321) 1.6%10 Oil evaroration @204C/22 h (ASTM D 972) 0.06% 0.1~
Relatively to the perfluorinated greases of the prior art, the very low degree of oil separation and evaporation results evident.
TRIBO-RHEOLOGICAL CHARACTERISTICS OF THE FORMULATED GREASE
The rheological characterization of the grease was carried out by means of measurements of its dynamic viscosity by using the plate/cone system mounted on a Rotovisco HAAKE 12 system, with M150 head (PKII/0.3).
The first type of measurements was carried out at 25C with increasing y (flow gradient) values (20; 40; 80 sec 1), with the viscosity of the grease being measured at start-up, and after 15 minutes. At each measurement, the used grease was replaced by fresh grease.
~ . .
~28~
For a grease according to the invention, formulated with Fomblin(R) z 1600, an early transient period was observed, the duration of which increases with decreasing ~ (from 5 to 6 minutes within the selected y range). During this period, the grease shows a rheopexi~
behaviour, followed by a stabilization of the signal at an equilibrium value higher than the initial values. The oscillations of the signal are, under these conditions, lower than of Z greases having a lower viscosity. The dynamic viscosity of the investigated grease at 80 sec 1 is equal to about 1,100 p (poises) whilst that of a grease formulated with Fomblin(R) Z 25 oil is of about 260 p under the same ~r .. .
~ \
conditions.
The behaviour of the viscosity over time, with constant values, shows hence that the grease according to the invention does not offer, at start-up, a higher resistance than under equilibrium conditions. This result, important in connection wi-th the power that the molar will have to apply at start-up, never occurred wi-th greases containing lower-viscosity PFPE-based oils.
The limited range of signal oscillation is 0 indicative of a better constancy of lubricating performance.
A second type of measurement was carried out under constant conditions of 40 sec 1, at temperatures of 25C;
50C, 100C. The endurance of the lubricating grease, at 100C, is exceptionally good, whilst, under the same conditions, a grease formulated with a lower-viscosity oil (Fomblin(R) Z 25) shows a trend to unhomogeneousness.
On the grease formulated according to the invention a tribological evaluation was carried out, by determining the welding load according to ASTM D 2596 Standard.
The welding load results higher than 700 kg (device measurement limit).
"~
BACKGR UND OF THE INYENTION
The object of the invention is the use of fluid perfluoropolyethers having a very high kinematic viscosity, comprised within the range of from 8,000 cSt to 40,000 cSt at 20C, and preferably of at least 10,000 cSt, as lubricating oils, and as the basic components of perfluo-rinated lubricating greases.
The use is well-known of fluid perfluoropoly-ethers, of neutral type, as lubricating oils endowed with high performance characteristics relating to the resistance to the atmospheric and chemical agents in general, even at high temperatures.
The products presently available from the market, suitable for use as lubricants, are low- or medium viscosity oils, with maximum viscosity values of the order of 2,000 cSt at 20C.
/
~?~ 54~1 THE PRESENT INVENTION
It has been surprisingly found now that the perfluoropolyethers having such a high kinematic viscosity as indicated above, show surprisingly improved charact~ristics of use, as lubricants, than the lower viscosity perfluoropolyethers used up to date.
The improvement in some specific properties is not attributal~ simply to the high viscosity of the product, and should be regarded as unforeseeable.
The perfluoropolyethers according to the invention, having viscosity values comprised within the above specified range, are constituted by linear chains of oxyperfluoroalkylene units selected from the following units:
-CF2CF20-, -CF20-, -CF2CF2CF20- .
The chain end groups are of perfluorinated neutral type.
In particular, the products belonging to the following classes are suitable:
.
1) R~FO(CF2cF2O)m(cF2o)n f wherein Rf and R'f, equal to, or different from each other, are either -CF3 or -C2F5, the perfluorooxy-alkylene units being randomly distributed along the chain, and indices _, n are such integers that the viscosity (which is a function of the average molecular weight) is within the indicated ranges. Products of .~
~855~
this type are disclosed in U.S. patent No. 3,665,041 and are known on the market under the trade name "Fomblin z(R),,;
5 2 ) R ' f(CF2CF2)pRf wherein Rf and R'f, equal LO, or different from each other, are either -CF3 or -C2F5 and index p is such an integer that the viscosity falls within the above indicated limits. Products of this type are disclosed in U.S. patent No. 4,523,039;
3) R'fO(CF2CF2CF2O)SRf wherein Rf and R'f, equal to, or different from each 3~ or -C2F5 or -C3F7, and index s is an integer such that the viscosity is comprised within the above indicated ranges. Products of this type are disclosed in European patent No 0 148 482.
On considering the very high viscosity of the products, and that such a viscosity, because of their linear structure, varies to a considerably low degree with varying temperature, as well as their very low volatility, the products of the invention can be advantageously used as lubricants for high temperatures.
It is known that a relationship exists which allows the friction coefficient ~ to be expressed as a function of Stribeck number ~N/P, wherein ~ = dynamic viscosity N = revolution speed: P = applied load per surface unit. Such a relationship, reported on a diagram allows the areas to be evidenced in which the system works under boundary lubrication, mixed lubrication and ,, ~85i~i~9 elastohydrodynamic lubrication conditions; on this regard, reference is made to "Lubricants", by D. Klamann (Verlag Chemie 1984), pages 33-foll..
The perfluoropolyether according to the present invention shows a surprising and unexpected improvement as relates to the wear rate under "mixed" lubrication conditions, as compared to the up to date commonly used perfluoropolyethers, having a much lower viscosity. This improvement cannot be simply explained by taking into account the difference in viscosity; it could be thought as being in some way connected with the molecular structure of the product.
The equipment used for measuring the wear rate is essentially constituted by a pin-on-rig system, consisting of a carbon steel (c 15) pin resting, for a surface area of 12 mm2, on the cylindrical surface, revolving at a rate of 350 rpm, of a specimen of the same material, having an average surface roughness of 0.15 microns, and a diameter of ~5 mm. The pin is loaded with a weight of 15 kg.
~ The procedure used in the test was as follows.
The specimens and the pins are cleaned in 1,1,2-trichloro-2,2,1-trifluoroethane, let dry and weighed. The specimen is assembled on the equipment in such a way that it can dip inside a tray containing the lubricating oil. After 1,000 revolutions, the specimen is dr~wn from the equipment, is cleaned in 1,1,2-trichloro-2,2,1-trifluoroethane, let dry and weighed again, and is then assembled again on the equipment. The measurement is repeated after 10,000 rpm.
Then the difference in weight is computed relatively to the number of run metres (~W/L):
~ r r .2 !3S5~
Test Time Z 1600 Z 25 Z 03 (Minutes)~W/L (~/m) ~W/L (~/m~~/L (g/m) 3 O.lxlO 5 3xlO 53.1xlO 5 lxlO 5 2xlO 52.5xlO 5 Z 1600 Perfluoropolyether belonging to Class (1), a commercial product Fomblin(R) Z by Montedison, having a kinematic viscosity of 16,000 cSt at 20C.
Z 25 Ditto, with a viscosity of 250 cSt -Z 03 Ditto, with a viscosity of 30 cSt.
The difference in the values measured between the investigated products evidences a lower wear rate in the high-viscosity oil. Above all, the necessary times for wear to be obtained are much higher for the highest-viscosity oil.
The perfluoropolyethers of the invention are particularly fit for the formulation of perfluorinated greases endowed with enhanced characteristics as compared to analogous products manufactured from lower-viscosity perfluoropolyether oils. Because of the very low value of high-temperature oil separation which was observed (even at a much higher oil percentage in the grease, than in the products of the prior art), the novel grease type results particularly suitable for high temperature usesO
A very meaningful characterizing property of the new grease type formulated with the perfluoropolyether oil according to the invention is the low static friction coefficient (measured as the starting resistent torgue).
- 6 - :
The method of preparation of the greases according to the invention is similar to the method as reported in European patent application No. EP 0 095 825, with the difference that, because of the high viscosity of the perflu~ropolyether, the kneading and the following homogenizing have to be performed under high temperature conditions (70C).
The oil amounts used for formulating polytetrafluoroethylene (PTFE)-thickened greases vary within the range of from 60% to 90%.
EXAMPLE OF PREPARATION OF A PERFLUORINATED GREASE
-15Oil used is Fomblin(R) Z 1600, an above-mentioned product, having a kinematic viscosity of 16,000 cSt at 20C.
It is introduced in the percentage of 74.1% by weight, relatively to the grease.
The thickening agent is a granular PTFE (average particle diameter 4-5 ~m; m.w. 40,000), used in the percentage of 25.9% by weight, relatively to the grease.
25The kneading and homogenizing method is reported in the above-cited patent.
To comparative purposes, a perfluorinated grease was prepared by using the same PTFE type, and Fomblin(R) 30Z 25 oil, having a viscosity of 250 cSt.
The formulation comprises 68.5% by weight of Fomblin(R) 2 25 and 31.5% by weight of PTFE.
z-r ~35~
CHEMICAL-PHYSICAL CHARACTERIZATION
OF THE FORMULATED GREASE
With Fomblin With Fomblin Consistency Z 1600z 25 Macropenetration mm/10 (ASTM D 217) 283 286 Macropenetration after 10,000 double shots, mm/10 (ASTM
D 217) 270 298 Oil separation @204C/30 h (FTMS 791-321) 1.6%10 Oil evaroration @204C/22 h (ASTM D 972) 0.06% 0.1~
Relatively to the perfluorinated greases of the prior art, the very low degree of oil separation and evaporation results evident.
TRIBO-RHEOLOGICAL CHARACTERISTICS OF THE FORMULATED GREASE
The rheological characterization of the grease was carried out by means of measurements of its dynamic viscosity by using the plate/cone system mounted on a Rotovisco HAAKE 12 system, with M150 head (PKII/0.3).
The first type of measurements was carried out at 25C with increasing y (flow gradient) values (20; 40; 80 sec 1), with the viscosity of the grease being measured at start-up, and after 15 minutes. At each measurement, the used grease was replaced by fresh grease.
~ . .
~28~
For a grease according to the invention, formulated with Fomblin(R) z 1600, an early transient period was observed, the duration of which increases with decreasing ~ (from 5 to 6 minutes within the selected y range). During this period, the grease shows a rheopexi~
behaviour, followed by a stabilization of the signal at an equilibrium value higher than the initial values. The oscillations of the signal are, under these conditions, lower than of Z greases having a lower viscosity. The dynamic viscosity of the investigated grease at 80 sec 1 is equal to about 1,100 p (poises) whilst that of a grease formulated with Fomblin(R) Z 25 oil is of about 260 p under the same ~r .. .
~ \
conditions.
The behaviour of the viscosity over time, with constant values, shows hence that the grease according to the invention does not offer, at start-up, a higher resistance than under equilibrium conditions. This result, important in connection wi-th the power that the molar will have to apply at start-up, never occurred wi-th greases containing lower-viscosity PFPE-based oils.
The limited range of signal oscillation is 0 indicative of a better constancy of lubricating performance.
A second type of measurement was carried out under constant conditions of 40 sec 1, at temperatures of 25C;
50C, 100C. The endurance of the lubricating grease, at 100C, is exceptionally good, whilst, under the same conditions, a grease formulated with a lower-viscosity oil (Fomblin(R) Z 25) shows a trend to unhomogeneousness.
On the grease formulated according to the invention a tribological evaluation was carried out, by determining the welding load according to ASTM D 2596 Standard.
The welding load results higher than 700 kg (device measurement limit).
"~
Claims (4)
1. Use as a lubricating oil, of a perfluoropoly-ether of neutral type, having a completely linear structure constituted by the sequence of one or more of the following oxyperfluo-roalkylene units:
-CF2CF2O-, -CF2O-, -CF2CF2CF2O-, and havinga kinematic viscosity comprised within the range of from 8,000 to 40,000 cSt at 20°C.
-CF2CF2O-, -CF2O-, -CF2CF2CF2O-, and havinga kinematic viscosity comprised within the range of from 8,000 to 40,000 cSt at 20°C.
2. Use as a lubricating oil,of a perfluoropoly-ether as defined in claim 1, wherein the kinematic viscosity is of at least 10,000 cSt.
3. Use as a lubricating oil, of a perfluoropoly-ether as defined in claim 1, wherein said perfluoropolyether is of the formula:
R'fO(CF2CF2O)nRf wherein Rf and R'f, equal to, or different from each other, are either -CF3 or -C2F5, the perfluorooxoyalkylene units are randomly distributed a long the chain, and m and n are integers such that the viscosity of perfluoropolyether is within the indicated ranges.
R'fO(CF2CF2O)nRf wherein Rf and R'f, equal to, or different from each other, are either -CF3 or -C2F5, the perfluorooxoyalkylene units are randomly distributed a long the chain, and m and n are integers such that the viscosity of perfluoropolyether is within the indicated ranges.
4. A perfluorinated lubricating grease comprising polytetrafluoroethylene and a perfluoropolyether of neutral type as defined in claim 1, 2 or 3, said grease comprising from 60% to 90% by weight of said perfluoropolyether based on the total weight of the grease.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT20322/86A IT1189486B (en) | 1986-05-06 | 1986-05-06 | USE OF A VERY HIGH VISCOSITY FLUID POLYPOLYERE AS LUBRICANT |
| IT20322A/86 | 1986-05-06 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1285549C true CA1285549C (en) | 1991-07-02 |
Family
ID=11165719
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000536351A Expired - Lifetime CA1285549C (en) | 1986-05-06 | 1987-05-05 | Use of a fluid perfluoropolyether, having a very high viscosity, as a lubricant |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0244838B1 (en) |
| JP (1) | JPS6322896A (en) |
| AT (1) | ATE78864T1 (en) |
| CA (1) | CA1285549C (en) |
| DE (1) | DE3780695D1 (en) |
| IT (1) | IT1189486B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110760361A (en) * | 2019-09-24 | 2020-02-07 | 中国石油化工股份有限公司 | Perfluoropolyether lubricating grease and preparation method thereof |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA1329586C (en) * | 1988-05-06 | 1994-05-17 | Takashi Tohzuka | Fluorine-containing grease and its preparation |
| US5171899A (en) * | 1988-05-17 | 1992-12-15 | Daikin Industries Ltd. | Process for production of 1,1,1-trifluoro-2,2-dichloroethane |
| IT1237887B (en) * | 1989-12-12 | 1993-06-18 | Ausimont Spa | PERFLUOROPOLIETEREI LUBRICANTS WITH WEAR PROPERTIES |
| WO1995013341A1 (en) * | 1993-11-12 | 1995-05-18 | Aktsionernoe Obschestvo Zakrytogo Tipa 'amtek' | Anti-friction modifying compound |
| JP3816118B2 (en) * | 1993-12-01 | 2006-08-30 | アウシモント、ソチエタ、ペル、アツィオーニ | Hydrogenated mineral or synthetic greases with improved properties |
| JP3875108B2 (en) * | 2002-01-15 | 2007-01-31 | Ｎｏｋクリューバー株式会社 | Low torque grease composition |
| DE102011055683A1 (en) | 2011-11-24 | 2013-05-29 | Götz von Foerster | Synthetic lubricant for use as a synovial fluid replacement |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3242218A (en) * | 1961-03-29 | 1966-03-22 | Du Pont | Process for preparing fluorocarbon polyethers |
| US3665041A (en) * | 1967-04-04 | 1972-05-23 | Montedison Spa | Perfluorinated polyethers and process for their preparation |
| US4523039A (en) * | 1980-04-11 | 1985-06-11 | The University Of Texas | Method for forming perfluorocarbon ethers |
| US4438006A (en) * | 1981-06-29 | 1984-03-20 | The United States Of America As Represented By The Secretary Of The Air Force | Perfluorinated aliphatic polyalkylether lubricant with an additive composed of an aromatic phosphine substituted with perfluoroalkylether groups |
| IT1150705B (en) * | 1982-03-19 | 1986-12-17 | Montedison Spa | PERFLUOROOLEFINE INSERTION PROCESS ON PERFLUOROPOLYETERS AND RELATED PRODUCTS |
| IT1152230B (en) * | 1982-05-31 | 1986-12-31 | Montedison Spa | PROCEDURE FOR THE PREPARATION OF LUBRICANT FATS BASED ON POLYTETRAFLUOROETHYLENE AND PERFLUOROPOLYETERS |
| US4438007A (en) * | 1982-09-14 | 1984-03-20 | The United States Of America As Represented By The Secretary Of The Air Force | Perfluorinated aliphatic polyalkylether lubricant with an additive composed of an aromatic phosphine substituted with perfluoroalkylether groups |
| EP0415462B1 (en) * | 1983-12-26 | 1996-05-08 | Daikin Industries, Limited | Halogen-containing polyether |
| JPS61113694A (en) * | 1984-11-07 | 1986-05-31 | Daikin Ind Ltd | Fluorine-containing grease composition |
-
1986
- 1986-05-06 IT IT20322/86A patent/IT1189486B/en active
-
1987
- 1987-05-05 CA CA000536351A patent/CA1285549C/en not_active Expired - Lifetime
- 1987-05-06 EP EP87106528A patent/EP0244838B1/en not_active Expired - Lifetime
- 1987-05-06 JP JP62109057A patent/JPS6322896A/en active Pending
- 1987-05-06 AT AT87106528T patent/ATE78864T1/en not_active IP Right Cessation
- 1987-05-06 DE DE8787106528T patent/DE3780695D1/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110760361A (en) * | 2019-09-24 | 2020-02-07 | 中国石油化工股份有限公司 | Perfluoropolyether lubricating grease and preparation method thereof |
| CN110760361B (en) * | 2019-09-24 | 2022-07-26 | 中国石油化工股份有限公司 | Perfluoropolyether lubricating grease and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| IT1189486B (en) | 1988-02-04 |
| EP0244838B1 (en) | 1992-07-29 |
| DE3780695D1 (en) | 1992-09-03 |
| ATE78864T1 (en) | 1992-08-15 |
| IT8620322A0 (en) | 1986-05-06 |
| JPS6322896A (en) | 1988-01-30 |
| EP0244838A1 (en) | 1987-11-11 |
| IT8620322A1 (en) | 1987-11-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5124058A (en) | Perfluoropolyether lubricants having antiwear properties | |
| US4941987A (en) | Lubricating greases | |
| EP0605403B1 (en) | Lubricating greases | |
| US2411159A (en) | Lubricant | |
| Reich et al. | Base oil properties of ionic liquids (C) | |
| CA1285549C (en) | Use of a fluid perfluoropolyether, having a very high viscosity, as a lubricant | |
| KR100964059B1 (en) | Low torque grease composition | |
| JP4421781B2 (en) | Grease composition for constant velocity joints | |
| US3882030A (en) | Self-lubricating bearing elements | |
| US5210123A (en) | Grease compositions employing a vinylidene fluoride-hexafluoroisobutylene copolymer thickening agent | |
| US4431556A (en) | Oxidation stable polyfluoroalkylether grease compositions | |
| Samyn et al. | Friction of polyoxymethylene homopolymer in highly loaded applications extrapolated from small-scale testing | |
| US4431555A (en) | Oxidation stable polyfluoroalkylether grease compositions | |
| Zhang et al. | Friction and wear behaviors of several polymers under oil‐lubricated conditions | |
| Sicre et al. | Rheological and tribological characterisation of six wet lubricants for space | |
| RU2290416C2 (en) | Antifriction composition polymeric material | |
| Anderson et al. | The lubrication of plastics by perfluoropolyether fluids | |
| Murphy et al. | Viscosities and Densities of Lubricating Fluids From− 40 to 700 F | |
| EP0475393A1 (en) | Lubricant and grease composition for ceramic material | |
| US6217791B1 (en) | Refrigerant incorporating a polyoxyalkylene glycol monomethylether | |
| RU2260036C1 (en) | Low-temperature instrumental oil | |
| Marchionni et al. | Viscosity of Perfluoropolyether Lubricants: Influence of Structure, Chain Dimensions and Molecular Interactions | |
| RU2216553C2 (en) | Antifriction polymeric material | |
| JPH059484A (en) | Lubricant and grease composition for material | |
| JPH02298588A (en) | Halogen-containing lubricant composition |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |