Solvent-diluted fluorine-based lubricant composition

Abstract

To provide a solvent-diluted fluorine-based lubricant composition capable of properly sliding without sticking in a wide variety of contact forms which are being miniaturized while maintaining excellent fluidity of a fluorine grease containing a perfluoropolyether oil as a base oil.SOLUTION: A solvent-diluted fluorine-based lubricant composition of the present invention contains a base oil, an additive and a fluorine-based solvent, wherein the base oil is a perfluoropolyether oil and the additive contains a fine solid powder which does not deform during lubrication. The solid powder preferably has an average particle size of 0.1 μm to 10.0 μm. The solid powder preferably contains a calcination-type polytetrafluoroethylene powder.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a solvent-dilutable fluorine-based lubricant composition. [Background technology]

[0002] Greases are often classified according to their base oil and thickener. Among these, greases thickened with perfluoropolyether oil, fluorine-based polymers such as polytetrafluoroethylene, or inorganic thickeners are called fluorine greases. Liquid lubricants in which fluorine grease is dispersed in fluorine-based solvents such as hydrofluoroether or hydrofluorocarbon are called solvent-diluted fluorine-based lubricants.

[0003] Fluorine grease possesses numerous excellent properties due to its base oil, including lubrication, heat resistance, oxidation stability, resistance to resins and rubbers, low dust generation, and chemical resistance. Fluorine grease is particularly often used in the precision and delicate parts of home appliances. Some home appliances may be used for over 10 years without maintenance, and fluorine grease, with its multi-functionality, can fully satisfy these requirements. However, fluorine grease is also expensive. Therefore, it is desirable to use it in the thinnest possible film while maintaining its performance.

[0004] Solvent-diluted fluorine-based lubricants form a thin fluorine grease film after application as the solvent evaporates. This reduces the amount of fluorine grease used, lowering costs. Furthermore, because solvent-diluted fluorine-based lubricants are low-viscosity liquid lubricants, they can be applied by methods such as dipping or brushing, improving work efficiency and productivity, and making application to parts with complex structures relatively easy. In addition, their excellent fluidity makes it easy to control the dispersibility of the fluorine grease components in the solvent by using additives as needed, allowing for proper distribution of the fluorine grease components. As a result, the fluorine grease film after drying becomes a uniform film with less variation, which in turn reduces the production cost of the parts forming the fluorine grease film.

[0005] As mentioned above, solvent-diluted fluorine-based lubricant compositions can be easily applied to parts ranging from simple to complex shapes, and are commonly used for gear-type components. However, with the increasing miniaturization of components, there is a growing demand for more precise and uniform application.

[0006] Regarding high dispersion technology for solvent-diluted fluorine-based lubricant compositions, for example, Patent Document 1 discloses a technology for a solvent-diluted fluorine-based lubricant composition containing a base oil, a solid lubricant, and a dispersibility improver.

[0007] In solvent-diluted fluorine-based lubricant compositions containing solid lubricants, the solid lubricant present in the fluorine grease film formed after the solvent evaporates deforms during friction between parts to provide lubrication. However, with the miniaturization of gear parts, there were cases where the lubricant could not be applied effectively, such as insufficient lubrication. Furthermore, depending on the contact pattern between parts, sticking of those parts together could occur. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2017-115099 [Overview of the project] [Problems that the invention aims to solve]

[0009] This invention was proposed in view of the above-mentioned conventional circumstances, and aims to provide a solvent-dilutable fluorine-based lubricant composition that maintains the excellent fluidity of a fluorine grease based on perfluoropolyether oil, while enabling proper sliding without sticking even in a wide variety of contact configurations as miniaturization progresses. [Means for solving the problem]

[0010] Conventionally, many fluorine-based greases used in gear-type parts contain solid lubricant components. When the space between parts is narrow, the solid lubricant component prevents contact between parts, and the solid lubricant itself deforms to provide lubrication. Research into the lubrication problems that occur in miniaturized parts in recent years has revealed that sliding problems occur because the torque required to move the miniaturized parts is lower than the deformation stress of the solid lubricant component. Therefore, the inventors diligently studied to solve the above-mentioned problems and found that by incorporating an additive consisting of a specific solid powder into fluorine grease, the fluorine grease has an appropriate viscosity, and even in environments where parts are in surface contact, for example, the fluorine grease intervenes between parts to provide excellent lubrication and effectively prevent sticking between parts. This led to the completion of the present invention.

[0011] (1) The first invention of the present invention is a solvent-diluted fluorine-based lubricant composition containing a base oil, an additive, and a fluorine-based solvent, wherein the base oil is a perfluoropolyether oil, and the additive is a fine substance that does not deform during lubrication. solid This is a solvent-dilutable fluorine-based lubricant composition containing powder.

[0012] (2) The second invention of the present invention is the same as the first invention, solid The powder is a solvent-dilutable fluorine-based lubricant composition with an average particle size of 0.1 μm or more and 10.0 μm or less.

[0013] (3) The third invention of the present invention is the first or second invention, wherein the solid powder contains sintered-type polytetrafluoroethylene powder, and is a solvent-diluted fluorine-based lubricant composition.

[0014] (4) The fourth invention of the present invention is the third invention, wherein the fluorine grease further contains unfired-type polytetrafluoroethylene powder as the additive, and is a solvent-diluted fluorine-based lubricant composition.

[0015] (5) The fifth invention of the present invention is any one of the first to fourth inventions, wherein the solvent-diluted fluorine-based lubricant composition further contains a dispersibility improver having an alkyl fluoride group with 1 to 10 carbon atoms and an acrylic group, and is a solvent-diluted fluorine-based lubricant composition.

[0016] (6) The sixth invention of the present invention is the fifth invention, wherein the dispersibility improver is contained in a ratio of 1 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the solid powder, and is a solvent-diluted fluorine-based lubricant composition.

[0017] (7) The seventh invention of the present invention is any one of the first to sixth inventions, wherein the fluorine-based solvent contains hydrofluoroether or hydrofluorocarbon, and is a solvent-diluted fluorine-based lubricant composition.

Advantages of the Invention

[0018] According to the present invention, while maintaining excellent performance, lubricity can be exhibited in any contact form, and sticking between parts can be prevented.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, specific embodiments of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. Note that the present invention is not limited to the following embodiments, and various modifications are possible without changing the gist of the present invention.

[0020] ≪1. Composition of Solvent-Diluted Fluorine-Based Lubricant Composition≫ The solvent-diluted fluorine-based lubricant composition according to this embodiment (hereinafter, also simply referred to as "lubricant composition") is formed by dispersing fluorine grease in a fluorine-based solvent. The fluorine grease contains a perfluoropolyether oil as a base oil and fine solid powder that does not deform during lubrication.

[0021] Note that the state where fluorine grease is "dispersed" in the fluorine-based solvent means that it also includes the state where fluorine grease is dissolved in the fluorine-based solvent.

[0022] (1) Base Oil (Perfluoropolyether Oil) The base oil contains a perfluoropolyether oil. The perfluoropolyether oil is not particularly limited, and examples thereof include those having a structure represented by the following general formulas (i) to (iv).

[0023] F-(CFCF3-CF2-O-) n -CF2-CF3··(i) (In the formula (i), n is 0 or a positive integer.) CF3-(O-CFCF3-CF2) p -(O-CF2-) q -O-CF3··(ii) (In the formula (ii), p and q are each independently 0 or a positive integer.) F-(CF2-CF2-CF2-O-) r -CF2-CF3··(iii) (In the formula (iii), r is 0 or a positive integer.) CF3-(O-CF2-CF2-) s -(O-CF2-) t -O-CF3··(iv) (In the formula (iv), s and t are each independently 0 or a positive integer.)

[0024] Specifically, commercially available products such as the Krytox series (manufactured by DuPont), FomblinY series (manufactured by Solvay Specialty Polymers Japan Co., Ltd.), FomblinM series (manufactured by Solvay Specialty Polymers Japan Co., Ltd.), FomblinW series (manufactured by Solvay Specialty Polymers Japan Co., Ltd.), FomblinZ series (manufactured by Solvay Specialty Polymers Japan Co., Ltd.), DemnamS series (manufactured by Daikin Industries, Ltd.), and PT series (manufactured by Nikka Chemical Co., Ltd.) can be used.

[0025] Furthermore, perfluoropolyether oils can be those having the structure described above, and among them, those with a kinematic viscosity of 15 mm at 40°C are particularly noteworthy. 2 / s~600mm 2 It is preferable to use one that is within the range of / s.

[0026] (2) Additives The lubricant composition according to this embodiment contains a fine solid powder that does not deform during lubrication as an additive to be added to the fluorine grease.

[0027] Regarding solid powders used as additives, "not deforming during lubrication" means that even when mechanical shear stress is applied to the solid powder, there is almost no change in its own shape. Such solid powders can provide excellent lubrication without altering the viscosity of the grease.

[0028] This means that, in conventional sliding parts where large torques are generated, lubrication can be obtained through the deformability of solid lubricants, for example. However, in recent sliding parts such as those in micro-components, the generated torque is small, so the solid lubricant additive cannot deform, and may even aggregate and adhere to the sliding part, resulting in insufficient lubrication. In this regard, the lubricant composition according to this embodiment uses fine particles as additives that do not deform during lubrication. solid By incorporating the powder, solidThe powder moderately inhibits the fluidity of the base oil, resulting in a viscosity suitable for lubricating sliding parts. Furthermore, because the solid powder is less prone to deformation, aggregation of solid powder particles and adsorption to sliding members are reduced, making it less likely for the powder to stick to the sliding parts.

[0029] Specifically, the fine solid powder that does not deform during lubrication is not particularly limited as long as it has the above-mentioned properties, but it is preferable that it has affinity with the base oil (perfluoropolyether oil) in order to disperse uniformly in the base oil. For example, in terms of having affinity with the base oil, it is more preferable to use calcined polytetrafluoroethylene.

[0030] Here, solid lubricants such as unfired polytetrafluoroethylene have an amorphous shape, a large specific surface area and oil absorption capacity, and can produce the viscosity of fluorine grease even in small amounts, so they have been widely used as conventional lubricants. However, such solid lubricants are prone to deformation due to shear stress during lubrication, and also deform under mechanical shear stress when dispersed in a fluorine-based solvent, exhibiting high viscosity. However, this can result in excessive viscosity for micro-parts, causing deformation of the parts or preventing them from sliding properly. In contrast, "fired polytetrafluoroethylene" has a fine particle shape that is close to spherical, has low oil absorption capacity, and is resistant to deformation even when shear stress is applied. Therefore, when dispersed in a fluorine-based solvent, the viscosity of the grease does not change easily even when mechanical shear stress occurs, and it can effectively prevent parts from sticking together via additives. If the shape of the solid powder is spherical as described above, it is preferable because even if the gap between parts in the sliding part becomes narrow and contact occurs, it becomes a point contact, and the frictional resistance does not increase.

[0031] Furthermore, the particle size of the solid powder can be appropriately selected depending on the part to which it is applied. For example, when considering application to fine parts, it is preferable to use a powder with an average particle size of 10.0 μm or less. Also, for the same amount of added powder, the smaller the particle size of the solid powder, the larger the contact area with the base oil perfluoropolyether oil, and the greater the affinity. Therefore, it is preferable to have the effect of reducing oil separation of the perfluoropolyether oil. Moreover, it is even preferable to use calcined polytetrafluoroethylene as the solid powder, as exemplified above, as it increases compatibility with the base oil perfluoropolyether oil and further reduces oil separation.

[0032] On the other hand, if the solid powder has an average particle size greater than 10.0 μm, the contact area with the base oil (perfluoropolyether oil) becomes smaller, meaning the affinity decreases. Therefore, even when blended by the same mass, the consistency will be higher and the fluidity will increase compared to powders with an average particle size of 10.0 μm or less, which can lead to more oil separation and make leakage from the application area more likely. While it is possible to reduce the consistency and oil separation of the grease by increasing the amount of solid powder blended, this increases the proportion of solid components in the grease, which can result in excessively high viscosity after the solvent has evaporated.

[0033] Thus, by making the particle size of the solid powder used as an additive finer, the affinity with perfluoropolyether oil can be increased, but the viscosity will increase, so it is preferable to select it appropriately depending on the environment in which it is used. Specifically, as mentioned above, for use in recent micro-components, it is preferable to use one with an average particle size of 10.0 μm or less, and more preferably one with an average particle size of 5.0 μm or less. There is no particular limit to the lower limit of the average particle size, but from the viewpoint of viscosity and handling, it is preferable to use one with a particle size of 0.1 μm or more.

[0034] The average particle size can be obtained using the laser diffraction method described in ISO 13320 (2020).

[0035] In the lubricant composition according to this embodiment, the combination of the above-mentioned solid powder and the base oil, perfluoropolyether oil, constitutes the substantial active ingredient. The proportion of this active ingredient in the composition (100% by mass of the composition) is preferably 1% by mass or more and 50% by mass or less, and more preferably 3% by mass or more and 25% by mass or less. If the amount of active ingredient in the composition is less than 1% by mass, the amount of active ingredient after solvent evaporation may be insufficient and may not be able to exist over the entire surface, resulting in an uneven, island-like distribution and poor lubricity. On the other hand, if the amount of active ingredient exceeds 50% by mass, it may not be possible to sufficiently reduce the viscosity, resulting in low fluidity of the solvent-diluted fluorine-based lubricant and poor handling. Therefore, the smoothness of the film formed after application and drying may be poor. Furthermore, if the amount of active ingredient is too high, the amount of residue after application and drying will be large, making it difficult to form a thin film, which is one of the original required characteristics.

[0036] The amount of solid powder to be blended is preferably determined based on the blending ratio with the base oil, perfluoropolyether oil. Specifically, it is preferable to blend the powder so that the mass ratio of perfluoropolyether oil to solid powder is in the range of 97:3 to 50:50. In relation to the blending ratio with perfluoropolyether oil, if the blending ratio of solid powder is less than 3% by mass, the lubricity of the fluorine grease after drying will be poor. On the other hand, if the blending ratio of solid powder exceeds 50% by mass, the viscosity of the fluorine grease after drying will be too high, and the torque will be too high in the dried state after the solvent has evaporated, potentially exceeding the sliding torque of the fine parts and causing problems such as the sliding parts sticking together.

[0037] Furthermore, in the lubricant composition according to this embodiment, a solid lubricant may be mixed in to adjust the viscosity and provide suitable lubricity, to the extent that it does not cause sticking at the sliding parts. The solid lubricant is not particularly limited, but it is preferable to use an uncalcined type of polytetrafluoroethylene.

[0038] When a solid lubricant is added further, solid The mixing ratio of powder and solid lubricant should be determined based on the required viscosity of the grease being used. Specifically, solid It is preferable to formulate the mixture so that the ratio of powder to solid lubricant is in the range of 100:0 to 50:50. Furthermore, it is more preferable to formulate it so that the ratio is in the range of 90:10 to 60:40.

[0039] (3) Dispersion improvers In the lubricant composition according to this embodiment, a dispersibility enhancer may be added. By including a dispersibility enhancer, the dispersibility of the additive (solid powder) in the lubricant composition can be improved, and thus the distribution of the additive (solid powder) in the fluorine grease after drying can be made uniform.

[0040] The dispersibility enhancer is not particularly limited and can be any compound that dissolves in a fluorinated solvent, regardless of the type of perfluoropolyether oil used as the base oil. For example, it is preferable to use a compound having a fluorinated alkyl group with 1 to 10 carbon atoms and an acrylic group.

[0041] Specifically, in a compound having a fluorinated alkyl group having 1 to 10 carbon atoms and an acrylic group, it is preferable that the fluorinated alkyl group is a perfluoroalkyl group having 1 to 10 carbon atoms. Furthermore, it is more preferable that the number of carbon atoms be 4 to 8, and particularly preferable that the number of carbon atoms be 6 from the viewpoint of recent PFOA regulations.

[0042] The amount of dispersibility improver added should preferably be adjusted appropriately based on the type of additive (solid powder) and its particle size, which determines the surface area. Since the dispersibility improver is adsorbed onto the surface of the additive, if the particle size of the additive is small, i.e., the surface area is large, the amount of dispersibility improver added should be greater than when the particle size is large, even if the amount of additive is the same.

[0043] For example, when forming a thin film of fluorine grease containing solid powder, the amount of dispersibility improver added is preferably 1 to 100 parts by mass, more preferably 5 to 50 parts by mass, and particularly preferably 10 to 30 parts by mass, per 100 parts by mass of solid powder. That is, when using calcined polytetrafluoroethylene with an average particle size of 10 μm or less as the solid powder, it is preferable that the amount of dispersibility improver be 1 to 100 parts by mass per 100 parts by mass of polytetrafluoroethylene.

[0044] Regarding the amount of dispersibility improver added, if it is less than 1 part by mass per 100 parts by mass of solid powder, it may not be able to effectively suppress the sedimentation of the solid powder. On the other hand, if it is added in a ratio exceeding 100 parts by mass per 100 parts by mass of solid powder, its effect will plateau, and excessive addition may cause the solid powder to harden into a cake when it settles. If the solid powder settles due to long-term storage, it can usually be redispersed by stirring, but if it hardens into a cake, the settled solid powder may aggregate, making it difficult to break down sufficiently by stirring and reducing its redispersibility. In addition, if the amount added is too high, the viscosity of the fluorine grease after drying may increase excessively, potentially promoting sticking between parts.

[0045] (4) Fluorine-based solvents The lubricant composition according to this embodiment is a solvent-diluted fluorine-based lubricant composition obtained by dispersing (or dissolving) a fluorine grease containing perfluoropolyether oil as a base oil in a fluorine-based solvent. The fluorine-based solvent is not particularly limited, but hydrofluoroether or hydrofluorocarbon is preferred.

[0046] Hydrofluoroethers and hydrofluorocarbons are particularly preferable in light of recent environmental concerns because they have high compatibility with perfluoropolyether oils and a lower global warming potential compared to other halogenated solvents. Specifically, commercially available products such as the NOVEC series (manufactured by 3M Japan Ltd.), the Asahi Clean series (manufactured by AGC Inc.), and the Bartlell series (manufactured by Mitsui DuPont Fluorochemicals Ltd.) can be used.

[0047] Furthermore, hydrofluoroolefins, which have recently begun to gain popularity as an environmentally friendly option, can be used. For example, products such as Suprion (manufactured by Mitsui DuPont Fluorochemicals Co., Ltd.) are commercially available and can be suitably used.

[0048] (5) Other ingredients In addition to the components described above, the lubricant composition according to this embodiment may contain various other components, as long as they do not hinder the effects of the components. For example, various other components such as friction modifiers, metal corrosion inhibitors, and rust inhibitors may be included.

[0049] ≪2. Method for producing solvent-diluted fluorine-based lubricant compositions≫ The lubricant composition according to this embodiment can be manufactured by known methods. Specifically, for example, a fluorine-based solvent such as hydrofluoroether is weighed into a container, a dispersibility improver is added while stirring using a known stirring method, and then a fluorine grease containing solid powder is added and dispersed. In addition, various other components are added and dispersed as needed. This makes it possible to obtain a solvent-diluted fluorine-based lubricant composition in which fluorine grease is dispersed in a solvent.

[0050] The dispersion treatment of fluorine grease in a fluorine-based solvent can be carried out using wet stirring and dispersion equipment such as a propeller stirrer, dissolver, dispermat, star mill, dyno mill, agitator mill, Creamix, or Filmix.

[0051] Furthermore, the process is not limited to adding each component in the order described above and mixing and stirring them separately. Depending on the dispersion capacity of the stirring and dispersion equipment used, each component may be added and mixed and stirred simultaneously, or only some of the components may be mixed and stirred simultaneously. In addition, when incorporating a solid lubricant such as uncalcined polytetrafluoroethylene as an additive, it is preferable to disperse it gently using a propeller stirrer and dissolver, considering the impact on deformation of the solid lubricant.

[0052] Furthermore, when fluorine grease is manufactured in advance and then dispersed in a fluorine-based solvent, the method for manufacturing the fluorine grease is not particularly limited and can be manufactured by known methods. Specifically, for example, it can be obtained by mixing a base oil, such as perfluoropolyether oil, with additives (solid powders) and various other components as needed, and then kneading the mixture at a temperature of about 100°C to 150°C.

[0053] In the production of fluorine grease, processes such as kneading, dispersion, dilution, and mixing of different types of grease can be performed. These processes can be carried out using well-known stirring and dispersion equipment such as a three-roll mill, a universal stirrer, a homogenizer, a colloid mill, or a rotation-orbit mixer (Awatori Rentaro). [Examples]

[0054] The present invention will be described in more detail below with reference to specific embodiments, but the present invention is not limited in any way to the following embodiments.

[0055] <Preparation of solvent-diluted fluorine-based lubricant compositions> In Examples 1-8 and Comparative Example 1, solvent-diluted fluorine-based lubricant compositions were prepared with the formulation ratios shown in Table 1 below. The formulation amounts are expressed in "mass%", and the following components were used to make up each composition.

[0056] [component] (Base oil) Perfluoropolyether oil A: Fomblin Y15 (manufactured by Solvay Specialty Polymers Japan Co., Ltd.) (Additives) Solid powder: Polytetrafluoroethylene (calcined type) (PTFE-A) Fluoro GT 105-RC (manufactured by Shamrock, USA) Solid lubricant: Polytetrafluoroethylene (unfired type) (PTFE-B) Fluoro GE 125-RC (manufactured by Shamrock, USA) (Dispersion improver) Dispersion improver: NOXBARRIER ST-462 (manufactured by Unimatec Co., Ltd.) (Fluorine-based solvents) Fluorine-based solvent A: NOVEC7200 (manufactured by 3M Japan Ltd.)

[0057] Furthermore, "NOXBARRIER ST-462," a dispersibility enhancer, is a compound having a perfluoroalkyl group with 6 carbon atoms and an acrylic group.

[0058] [Preparation Procedure] Using a rotary-orbit mixer and a three-roll mixer, a grease composition was prepared such that the mixing ratio of the base oil and additives consisting of solid powder (PTFE-A) and solid lubricant (PTFE-B) was as shown in Table 1 below.

[0059] On the other hand, a fluorine-based solvent was weighed into a container and stirred with a propeller agitator while a dispersibility enhancer was added to it. Next, the prepared grease composition was added to the fluorine-based solvent to which the dispersibility enhancer had been added and stirred and mixed. This produced a solvent-diluted fluorine-based lubricant composition in which fluorine grease was dispersed in the fluorine-based solvent.

[0060] Comparative Example 1 is a sample corresponding to a conventional solvent-diluted fluorine-based lubricant composition. Comparative Example 2 is an existing product A (our product) made of uncalcined polytetrafluoroethylene.

[0061] <Rating> The following evaluations were performed on the prepared solvent-diluted fluorine-based lubricant composition.

[0062] [Viscosity Evaluation] Regarding the viscosity evaluation of the lubricating thin film (grease thin film) formed on the part surface by the solvent-diluted fluorine-based lubricant composition, the shear viscosity was measured and evaluated according to the following procedure. Specifically, about 50 g of the prepared solvent-diluted fluorine-based lubricant was placed in a 100 mL beaker, and the fluorine-based solvent was distilled off at room temperature. The shear viscosity of the fluorine grease after solvent distillation was measured using a rheometer under the following conditions.

[0063] As a result of the measurement, when the shear viscosity was less than 60 Pa, it was evaluated as '〇' indicating that the viscosity of the grease was sufficiently low and the fluidity was good; when the shear viscosity was 60 Pa or more and less than 100 Pa, it was evaluated as '△' indicating that the viscosity of the grease was slightly high and the fluidity was insufficient; when the shear viscosity was 100 or more, it was evaluated as '×' indicating that the viscosity of the grease was high and the fluidity was not sufficient.

[0064] (Measurement Conditions of Shear Viscosity) Evaluation tester: MCR-101 Shear rate: 29.7 s -1 (10 rpm) Test temperature: 20 °C Measurement time: 5 minutes

[0065] [Anti-seizure Property Test] Regarding the anti-seizure property between parts by the solvent-diluted fluorine-based lubricant, it was evaluated by measuring the friction coefficient between parts in a surface contact form under the following test conditions using a surface property tester (manufactured by Shin-Tong Science Co., Ltd.) as a test machine. Specifically, the solvent-diluted fluorine-based lubricant composition was applied to an ABS plate 1 (40 mm × 120 mm × t2 mm), dried, and then fixed to the fixture (movable part) on the lower side of the test machine with the application surface facing up. An ABS plate 2 (25 mm × 25 mm × t2 mm) was attached to the fixture on the upper side of the test machine with double-sided tape, overlapped on the application surface, and a weight was placed so that the surface pressure became 1.26 kPa. Then, after standing for 1 hour, the friction coefficient when the fixture fixing the ABS plate 1 was slid 20 mm at a speed of 1.33 mm / s was measured.

[0066] Based on the measurement results, if the coefficient of friction was less than 0.6, it was evaluated as "○" indicating good performance as it has fluidity and parts can easily slide against each other; if the coefficient of friction was between 0.6 and 0.8, it was evaluated as "△" indicating that it has some fluidity and parts can slide against each other, making it usable under certain conditions; and if the coefficient of friction was 0.8 or higher, it was evaluated as "×" indicating that it has almost no fluidity and parts may stick together.

[0067] (Measurement conditions for the coefficient of friction) Evaluation testing machine: Surface properties tester (Tribogear Type 14) Test piece: ABS sheet (upper and lower) Surface contact form Load: Surface pressure 1.26 kPa Sliding motion: sliding Sliding speed: 1.33 mm / s Sliding distance: 20mm

[0068] <Result> Table 1 below shows the compositions of solvent-diluted fluorine-based lubricant compositions in the examples and comparative examples, along with a summary of the evaluation test results described above.

[0069] [Table 1]

[0070] The results shown in Table 1 indicate that the lubricant composition of the example containing calcined polytetrafluoroethylene as a solid powder additive exhibits low viscosity of the fluorine grease after drying and good grease fluidity. It also demonstrates good resistance to seizing, suppressing the sticking of parts in surface contact configurations and enabling sliding with low torque.

[0071] However, the evaluation results from Examples 7 and 8 show that if the proportion of uncalcined polytetrafluoroethylene, which is a solid lubricant, increases, or if the total content of the solid lubricant and dispersibility improver increases, the viscosity increases and the resistance to sticking decreases. Since the boundary conditions under which the lubricant becomes unusable differ depending on the part used, when manufacturing a solvent-diluted fluorine-based lubricant composition, the usage environment and other factors should be considered, and an appropriate blending amount should be selected according to the usage conditions such as the sliding torque of the part used.

[0072] On the other hand, in the lubricant compositions of Comparative Examples 1 and 2 (existing product A), which use only unfired polyfluoroethylene, a solid lubricant, as in the conventional method, the viscosity of the fluorine grease after drying is high and the fluidity of the grease is poor, resulting in poor adhesion resistance and insufficient suppression of adhesion in surface contact form. Therefore, there is a risk of causing defects such as deformation of micro-parts and poor sliding.

Claims

1. A solvent-diluted fluorine-based lubricant composition containing a base oil, additives, and a fluorine-based solvent, The base oil is perfluoropolyether oil, The aforementioned additive includes a solid powder containing calcined polytetrafluoroethylene powder. A solvent-diluted fluorine-based lubricant composition.

2. The solid powder has an average particle size of 0.1 μm or more and 10.0 μm or less. The solvent-diluted fluorine-based lubricant composition according to claim 1.

3. The aforementioned additive further comprises uncalcined polytetrafluoroethylene powder. The solvent-diluted fluorine-based lubricant composition according to claim 1.

4. The solvent-diluted fluorine-based lubricant composition is The dispersibility enhancer further comprises a fluorinated alkyl group having 1 to 10 carbon atoms and an acrylic group. The solvent-diluted fluorine-based lubricant composition according to claim 1.

5. The dispersibility enhancer is contained in a proportion of 1 part by mass or more and 100 parts by mass or less per 100 parts by mass of the solid powder. The solvent-diluted fluorine-based lubricant composition according to claim 4.

6. The aforementioned fluorine-based solvent is Containing hydrofluoroether or hydrofluorocarbon, The solvent-diluted fluorine-based lubricant composition according to claim 1.

Images