JP2573948C - - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lubricating oil composition for a mechanical device having an orifice mechanism, and more particularly to a lubricating oil composition for various mechanical devices having an orifice mechanism. And a lubricating oil composition having excellent operability. [Problems to be Solved by Conventional Techniques and Inventions] Conventionally, mechanical devices having an orifice mechanism, such as hydraulic machines such as automobile shock absorbers and door closers, and various mechanical devices such as automatic refueling devices for changing train points, have been used. The lubricating oil to be used, especially considering the operability at low temperatures,
A base oil having a relatively low pour point (about −15 ° C.) mixed with a large amount of a pour point depressant to improve the pour point to about −35 ° C. is used. However, such lubricating oils increase hydraulic resistance at low temperatures, causing various disadvantages, such as a reduction in low-temperature shock absorption in a shock absorber, a low-temperature operability in a door closer, and a railway point. In the refueling device for switching, problems such as inability to refuel at low temperatures have occurred. Further, in addition to these problems, a polymer (such as polymethacrylate) blended in a large amount as a pour point depressant is subjected to mechanical shearing, so that there is a problem that its performance changes greatly with time. [Means for Solving the Problems] Accordingly, the present inventor has solved the problems of the lubricating oil used in the various types of mechanical devices as described above, improved the operability at low temperatures, and maintained the performance for a long time. Intensive research to develop a new lubricant. As a result, they found that a lubricating base oil having a specific property and a compound containing an appropriate additive could achieve the intended purpose, and based on this finding, completed the present invention. . That is, the present invention relates to (A) a deep-dewaxed oil having a kinematic viscosity at 40 ° C of 3 to 500 cSt, a pour point of -25 ° C or less, and a cloud point of -25 ° C or less as a base oil. , (B) at least one viscosity index improver and / or pour point depressant selected from α-olefin polymers and α-olefin copolymers in an amount of 0.01% by weight or more of the total amount of the composition, and (C) ) At least one phosphorous extreme pressure agent selected from phosphate esters, phosphite esters, phosphate amine salts and phosphite amine salts in an amount of 0.01% by weight or more of the total amount of the composition, and The (
An object of the present invention is to provide a lubricating oil composition for a mechanical device having an orifice mechanism, wherein the total amount of the component (B) and the component (C) is 11.5% by weight or less. As described above, the properties of the lubricating oil used in the present invention are as follows.
It is in the range of 500 cSt, preferably in the range of 5 to 300 cSt. If the kinematic viscosity is less than 3 cSt, safety is not ensured due to high flammability, and extreme pressure resistance and wear resistance are disadvantageously reduced. On the other hand, if the kinematic viscosity exceeds 500 cSt, the viscous resistance is too large and various Cause serious trouble. The lubricating base oil has a pour point of -25 ° C or lower, preferably -30 ° C or lower. If the pour point exceeds -25 ° C., the low-temperature characteristics are inferior, so a large amount of pour point depressant must be added, and as a result, various disadvantages occur due to an increase in hydraulic resistance. Further, the lubricating base oil has a cloud point of −25 ° C. or less, preferably −30 ° C.
It is as follows. If the cloud point exceeds -25 ° C, there is a possibility that a mechanical device having an orifice mechanism using the same will not operate sufficiently at low temperatures. The lubricating base oil of the present invention is particularly characterized in that the cloud point is −25 ° C. or lower, and since both the pour point and the cloud point are extremely low, the lubricating oil of various mechanical devices having an orifice mechanism is used. It works effectively as Here the pour point is -25
If the cloud point is higher than −25 ° C., the operability is lowered because the orifice of the mechanical device is clogged at a low temperature. The deeply dewaxed oil, which is the lubricating base oil of the present invention, is specifically prepared by subjecting a paraffin-based crude oil, an intermediate-based crude oil, or a naphthenic-based crude oil to atmospheric distillation or a residual oil obtained by atmospheric distillation. The distillate obtained by distillation under reduced pressure is obtained by purifying according to a conventional method and further deep-waxing. The method for refining the distillate at this time is not particularly limited, and various methods can be considered. Usually, (a) hydrogenation treatment, (b) dewaxing treatment (solvent dewaxing or hydrogenation dewaxing), (c) solvent extraction treatment, (d) alkali distillation or sulfuric acid washing treatment, and (e) clay treatment alone Or by combining them in an appropriate order. It is also effective to repeat the same process in a plurality of stages. For example, hydrogenated distillate or hydrogenated, followed by alkali distillation or sulfuric acid washing, hydrogenated distillate, dewaxing, distillate oil solvent After the extraction treatment, there are a method of performing a hydrotreatment, a method of performing a two-stage or a three-stage hydrogenation treatment on the distillate, and a method of subsequently performing an alkali distillation or a sulfuric acid washing treatment. As the lubricating base oil of the present invention, the refined oil thus obtained is preferably subjected to a dewaxing treatment again to obtain a deeply dewaxed oil. The dewaxing process performed here is called a deep dewaxing process, and is performed by a solvent dewaxing process under severe conditions, a contact hydrodewaxing process using a zeolite catalyst, or the like. In the present invention, a lubricating oil composition is prepared by adding a specific viscosity index improver and / or a pour point depressant (B) and a specific phosphorus-based extreme pressure agent (C) to the deeply dewaxed oil base oil (A). And Here, as the specific viscosity index improver and / or pour point depressant, at least one selected from α-olefin polymers and α-olefin copolymers (for example, ethylene-propylene copolymer) is used as a component. I do. Among them, α-olefin polymers and α-olefin copolymers having a number average molecular weight of 1,000 to 30,000, particularly ethylene-α-olefin copolymers having a number average molecular weight of 1,000 to 10,000 are preferred. The specific phosphorus-based extreme pressure agent is at least one selected from phosphate esters (tricresyl phosphate (TCP) and the like), phosphite esters, phosphate ester amine salts, and phosphite ester amine salts. As a component. The components (B) and (C) used in the lubricating oil composition of the present invention are each added in an amount of 0.01% by weight or more based on the total amount of the composition, and (C) The total amount of the added components is 11.5% by weight or less. The lubricating oil composition may further contain an antiwear agent, an oiliness agent, or an antioxidant, if desired. However, the amount of the additive is defined as the total amount of the additives including (B) and (C). It is preferably 11.5% by weight or less of the total amount of the substance. Here, for example, examples of the antiwear agent include organic molybdenum compounds such as MoDTP and MoDTC; organic boron compounds such as alkyl mercaptyl borate; solid lubricants such as graphite, molybdenum disulfide, antimony sulfide, boron compounds, and polytetrafluoroethylene. Agent-based antiwear agents and the like. Examples of the oil agent (friction modifier) include higher fatty acids such as oleic acid and stearic acid; higher alcohols such as oleyl alcohol; amines; esters; fats and oils; sulfurized fats and oils; Examples of the antioxidant include various compounds such as phenol compounds, amine compounds, sulfur compounds, and phosphorus compounds. The lubricating oil composition of the invention described above may further contain an appropriate amount of a corrosion inhibitor, a rust inhibitor, a detergent / dispersant, a defoamer, or the like, if desired. EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. Comparative Example 1 A base oil obtained by subjecting a distillate from an intermediate base crude oil to two-stage hydrogenation treatment and further deep dewaxing treatment (hydrodewaxing treatment using a zeolite catalyst) (kinematic viscosity at 40 ° C. 1
0 cSt, pour point -42.5 ° C, cloud point -45 ° C, viscosity index 80), 0.5% by weight of zinc dithiophosphate (Zn-DTP) (ratio to the total amount of the composition; the same applies hereinafter), molybdenum dithiophosphate. (Mo-DTP) 0.5% by weight, tricresyl phosphate (TCP) 0.5% by weight, and 5% by weight of polymethacrylate (number average molecular weight 60,000) as a viscosity index improver and / or a pour point depressant (The ratio to the total amount of the composition finally obtained) was added, and the kinematic viscosity at 40 ° C. was 15 cSt, and the pour point was −
A lubricating oil composition having a cloud point of -45 ° C or lower at 45 ° C or lower was obtained. This lubricating oil composition is applied to an automobile shock absorber (cylindrical shock absorber: rod 20 mm (diameter) × 400 mm (length), outer cylinder 43 mm (diameter) × 400 mm
(Length), inner cylinder 30mm (diameter) x 350mm (length)), and after elapse of a predetermined time at a temperature of -30 ° C, the outer cylinder is moved up and down under the conditions of a speed of 0.1m / sec and a stroke of ± 30mm. By moving the shock absorber, the working load of the shock absorber (impact force at which the shock absorbing action is started) was measured. Next, the outer cylinder of the shock absorber was heated at a temperature of 15 ° C. and a speed of 1 m with a vibrator.
After applying 1 million times of vibration under the condition of ± 30 mm / sec and stroke ± 30 mm to give shear stress,
The working load of the shock absorber was measured under the same conditions as described above. The measurement results of the working load of the shock absorber before and after the vibration are shown in the table. Example 1 In Comparative Example 1, instead of 5% by weight of polymethacrylate (number average molecular weight 60,000) as a viscosity index improver, 10% by weight of ethylene-α-olefin copolymer (number average molecular weight 3600) (final Comparative Example 1 was carried out in the same manner as in Comparative Example 1 except that a lubricating oil composition having a kinematic viscosity at 40 ° C of 15 cSt, a pour point of -45 ° C, and a cloudy point of -45 ° C was obtained. Was. Next, using the obtained lubricating oil composition, the working load of the shock absorber before and after the vibration was measured in the same manner as in Comparative Example 1. The results are shown in the table. In Comparative Example 2 Comparative Example 1, except for not blending the polymethacrylate as viscosity index improvers and / or pour point depressants, in the same manner as in Comparative Example 1 to prepare a lubricating oil composition. Next, using the obtained lubricating oil composition, the working load of the shock absorber before and after the vibration was measured in the same manner as in Comparative Example 1. The results are shown in the table. Comparative Example 3 In Comparative Example 2 , a distillate from an intermediate base crude oil was hydrotreated as a base oil,
Further, a base oil (kinematic viscosity at 40 ° C. of 10 cSt, pour point of −35 ° C., cloud point of −33 ° C., viscosity index of 82) obtained by deep dewaxing treatment (hydrodewaxing treatment using a zeolite catalyst) was used. Except for this, the working load of the shock absorber before and after the vibration was measured in the same manner as in Comparative Example 2 . The results are shown in the table. Comparative Example 4 In Comparative Example 2 , a base oil obtained by subjecting a distillate from an intermediate base crude oil to a solvent extraction treatment as a base oil (kinematic viscosity at 40 ° C. 10 cSt, pour point −17.5 ° C., cloud point −
The working load of the shock absorber before and after the vibration was measured in the same manner as in Comparative Example 2 except for using 10 ° C. and a viscosity index of 90). The results are shown in the table. Comparative Example 5 In Comparative Example 2 , a base oil obtained by subjecting a distillate from a naphthene-based crude oil to a solvent extraction treatment as a base oil (kinematic viscosity at 40 ° C. 10 cSt, pour point −35 ° C., cloud point −20 ° C.) The working load of the shock absorber before and after the vibration was measured in the same manner as in Comparative Example 2 , except that the viscosity index 50) was used. The results are shown in the table. Comparative Example 6 5% by weight of a polymethacrylate (number average molecular weight of 60,000) as a viscosity index improver and / or a pour point depressant was added to the lubricating oil composition prepared in Comparative Example 4 (total amount of the finally obtained composition). Kinematic viscosity at 40 ° C. of 15 cS
t, a lubricating oil composition having a pour point of -35 ° C and a cloud point of -10 ° C was obtained. Next, using the obtained lubricating oil composition, the working load of the shock absorber before and after the vibration was measured in the same manner as in Comparative Example 1 . The results are shown in the table. Comparative Example 7 10% by weight of an ethylene-α-olefin copolymer (number average molecular weight of 3600) as a viscosity index improver was added to the lubricating oil composition prepared in Comparative Example 4 (ratio to the total amount of the finally obtained composition) ) To obtain a lubricating oil composition having a kinematic viscosity at 40 ° C. of 15 cSt, a pour point of −20 ° C., and a cloud point of −10 ° C. Next, using the obtained lubricating oil composition, the working load of the shock absorber before and after the vibration was measured in the same manner as in Comparative Example 1. The results are shown in the table. The following can be seen from the above table. That is, the pour point, also lower the pour point by adding polymethacrylate to the high base oil of the cloud point, but the operation load at low temperatures is improved, its no persistence (see Comparative Example 1 and Comparative Example 6) . Pour point, one using a low base oil having a cloud point and polymethacrylate or ethylene -α- olefin copolymer is smaller over a long period of time operation load at low temperatures, also, it is also sufficient that the shear stability (compare See Example 1 and Example 1 ). In particular, those obtained by adding an ethylene-α-olefin copolymer to this base oil have a very low operating load at low temperatures, and have sufficient durability and shear stability (see Example 1 ). [Effect of the Invention] As described above, the lubricating oil composition of the present invention has good operability at low temperatures,
For example, when used in a shock absorber, the effect of absorbing the shock is remarkable, and the effect is persistent and stable. In addition, since the effect can be sufficiently exhibited even by adding a small amount of a polymer such as an ethylene-α-olefin copolymer, the polymer has excellent shear stability and can be used for a long time. Therefore, the lubricating oil composition of the present invention can be applied to mechanical devices having various orifice mechanisms, such as hydraulic machines such as automobile shock absorbers and door closers, and automatic lubricating devices for railway point switching, and particularly to mechanical devices exposed to low temperatures. Widely and effectively used.

Claims (1)

Claims (1) (A) A deep-dewaxed oil having a kinematic viscosity at 40 ° C of 3 to 500 cSt, a pour point of -25 ° C or lower, and a cloud point of -25 ° C or lower. To base oil,
(B) at least one kind of a viscosity index improver and / or a pour point depressant selected from an α-olefin polymer and an α-olefin copolymer having a number average molecular weight of 1,000 to 10,000, in an amount of 0.01 wt. % Or more, and (C) at least one phosphorus-based extreme pressure agent selected from phosphate esters, phosphite esters, phosphate amine salts and phosphite amine salts, in an amount of 0.01% by weight of the total amount of the composition. %
A lubricating oil composition for a mechanical device having an orifice mechanism, wherein the total amount of the components (B) and (C) is 11.5% by weight or less.