Dilution-type lubricant

Abstract

To provide a diluted lubricant using a low GWP solvent that is excellent in solubility, lubricity and visibility.SOLUTION: A diluted lubricant in the present invention comprises a base oil, a fluorescent agent and a fluorine-based solvent. The fluorine-based solvent is capable of dissolving the base oil and the fluorescent agent, and contains a hydrochlorofluoroolefin. In the present invention, GWP of the fluorine-based solvent is preferably less than 30. The fluorescent agent preferably includes an oxazole-based or coumarin-based fluorescent agent.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to diluted lubricants using low GWP solvents. [Background technology]

[0002] Diluted lubricants, in which base oil is diluted with a solvent, have been known for some time. This allows for less base oil to be used, leading to cost savings. After the diluted lubricant is applied to a component, the solvent evaporates, forming a thin lubricating film. While this lubricating film has the lubricating properties of the base oil, it is very thin and therefore has poor visibility. For this reason, the invention described in Patent Document 1 adds a fluorescent agent, thereby improving visibility. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2018-150396 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in view of growing concerns about global warming, it is preferable that the global warming potential (GWP) of a solvent is low. The invention described in Patent Document 1 cites hydrofluoroethers (HFEs) and hydrofluorocarbons (HFCs) as low-GWP solvents (see paragraph

[0039] of Patent Document 1), but solvents with even lower GWP are desired.

[0005] Furthermore, when a low-GWP solvent is used to replace HFE or HFC, the solubility of the base oil or fluorescent agent decreases, raising concerns about residual solvents remaining undissolved.

[0006] Therefore, the present invention has been made in view of the above points, and an object of the present invention is to provide a diluted lubricant that uses a low GWP solvent and has excellent solubility, lubricity, and visibility. [Means for solving the problem]

[0007] The diluted lubricant of the present invention contains a base oil, a fluorescent agent, and a fluorine-based solvent, and the fluorine-based solvent is capable of dissolving the base oil and the fluorescent agent, and contains a hydrochlorofluoroolefin. The fluorescent agent includes an oxazole or coumarin. It is characterized by:

[0008] In the present invention, the GWP of the fluorine-based solvent is preferably less than 30. 。

[0009] In the present invention, the base oil preferably contains at least one of synthetic hydrocarbon oil, silicone oil, and fluorine oil.

[0010] In the present invention, when the sum of the base oil and the fluorine-based solvent is 100 mass %, the fluorine-based solvent is preferably contained in an amount of 60 mass % or more and 99.5 mass % or less. [Effects of the Invention]

[0011] According to the diluted lubricant of the present invention, by using a hydrochlorofluoroolefin as a fluorine-based solvent, it is possible to achieve a lower GWP than HFEs and HFCs, and to maintain excellent solubility and lubricity. DETAILED DESCRIPTION OF THE INVENTION

[0012] An embodiment of the present invention (hereinafter abbreviated as "embodiment") will be described in detail below. Note that the present invention is not limited to the following embodiment, and can be practiced with various modifications within the scope of the gist. Furthermore, the notation "to" includes both the lower limit and the upper limit as a range.

[0013] <Background to this embodiment> Dilution-type lubricants, which have traditionally been used in the sliding parts of home appliances and machinery, are made by diluting base oils or solid components with a solvent. The solvent is a fluorine-based solvent, such as hydrofluoroether (HFE), hydrofluorocarbon (HFC), or perfluorocarbon (PFC).

[0014] However, the GWP (100-year value) of these fluorinated solvents is at least around 56, so an even lower GWP is required. They also need to be non-flammable. Furthermore, the fluorinated solvent must be able to adequately dissolve the base oil and solid components, and after the solvent evaporates, a uniform thin film of the base oil and solid components must be formed, providing excellent lubricity.

[0015] Therefore, the inventors have conducted extensive research into diluted lubricants containing a base oil, a fluorescent agent, and a fluorine-based solvent, and as a result have found that by using a hydrochlorofluoroolefin as the fluorine-based solvent, it is possible to achieve low GWP, excellent solubility, and lubricity.

[0016] <Diluted Lubricant of the Present Embodiment> The diluted lubricant in this embodiment contains a base oil, a fluorescent agent, and a fluorine-based solvent, and the fluorine-based solvent is capable of dissolving the base oil and the fluorescent agent and is characterized by containing a hydrochlorofluoroolefin.

[0017] As described above, the fluorine-based solvent used in the diluted lubricant of this embodiment is a hydrochlorofluoroolefin, which is non-flammable and has a low GWP, thereby reducing the environmental impact.

[0018] The diluted lubricant of this embodiment dissolves the base oil and the fluorescent agent using a fluorine-based solvent, thereby preventing residual residue. Specifically, the base oil and the fluorescent agent can be appropriately dissolved by selecting and blending the fluorine-based solvent. Furthermore, the diluted lubricant requires less base oil, leading to cost reduction.

[0019] The diluted lubricant of this embodiment also contains a fluorescent agent, which allows the diluted lubricant to be applied to a surface of a component, and after the solvent has evaporated, the resulting thin lubricating coating will emit light when exposed to UV light, providing excellent visibility.

[0020] (Fluorinated solvents) The fluorine-based solvent used in this embodiment includes a hydrochlorofluoroolefin (HCFO) capable of dissolving the base oil and the fluorescent agent. The hydrochlorofluoroolefin applicable to this embodiment is preferably Cerefhin (registered trademark) 1233Z (manufactured by Honmachi Chemical Industry Co., Ltd.) or Amorea (registered trademark) AS-300 (manufactured by AGC).

[0021] The chemical formula of Cerefin 1233Z is CF3CH=CHCl (1-chloro-3,3,3-trifluoropropene), and the chemical formula of Amorea AS-300 is CHF2CF=CHCl (1-chloro-2,3,3-trifluoropropene).

[0022] In this embodiment, the GWP (100-year value) of the fluorine-based solvent is preferably less than 30, more preferably less than 10, even more preferably 5 or less, and even more preferably 1 or less. Note that all GWP values ​​described in this specification are 100-year values. The GWP of the fluorine-based solvent of this embodiment is lower than that of HFEs (for example, GWP of about 56 to 1000) and HFCs (for example, GWP of about 136 to 2000), and the environmental load can be effectively reduced.

[0023] The fluorine-based solvent may contain a solvent other than hydrochlorofluoroolefin, as long as the combined GWP of the hydrochlorofluoroolefin and the solvent other than hydrochlorofluoroolefin is less than 30. Cerefin 1233Z and Amorea AS-300 both have a GWP of 1 or less, which is extremely low. Note that even if the GWP of the solvent other than hydrochlorofluoroolefin is 30 or more, it is included in the scope of this embodiment as long as the GWP of the fluorine-based solvent can be reduced to less than 30 by mixing it with hydrochlorofluoroolefin.

[0024] (base oil) The base oil used in this embodiment preferably contains at least one of synthetic hydrocarbon oil, silicone oil, and fluorine oil. Examples of synthetic hydrocarbon oils that can be used include, but are not limited to, Spectrasyn 4 (manufactured by Exxon Mobil Corp.) and Lucant HC-10 (manufactured by Mitsui Chemicals, Inc.). Examples of silicone oils include KF96-20CS (manufactured by Shin-Etsu Chemical Co., Ltd.) and KF50-100CS (manufactured by Shin-Etsu Chemical Co., Ltd.). Examples of fluorine oils that can be used include FOMBLIN® Y06 (manufactured by Solvay Specialty Polymers Japan Ltd.), FOMBLIN M03 (manufactured by Solvay Specialty Polymers Japan Ltd.), DEMNUM® S-65 (manufactured by Daikin Industries, Ltd.), and KRYTOX® GPL103 (manufactured by Chemours). The kinematic viscosity of the base oil is not limited, but a viscosity of 500 mm at 40°C is preferred. 2 / s or less is preferable, and 100 mm 2 / s or less is more preferable, and 50 mm 2 Thin lubricating films are often used under low load conditions, and by using a low viscosity oil, it is possible to achieve both excellent lubricity and solubility in solvents.

[0025] In this embodiment, when the total of the base oil and the fluorine-based solvent is 100 mass%, the fluorine-based solvent is preferably contained in the range of 60 mass% to 99.5 mass%, more preferably in the range of 70 mass% to 99.5 mass%, and even more preferably in the range of 80 mass% to 99 mass%, so that the base oil can be appropriately dissolved in the fluorine-based solvent.

[0026] (fluorescent agent) The fluorescent agent used in this embodiment preferably contains an oxazole or coumarin, or may contain both an oxazole and a coumarin.

[0027] Although not limited thereto, it is preferable to use fluorescent agents A to D shown in Table 1 below as oxazole-based and coumarin-based fluorescent agents.

[0028] [Table 1]

[0029] Two or more types may be selected from the above fluorescent agents A to D. Furthermore, although not limited thereto, when the total of the fluorescent agent and the fluorinated solvent is 100 mass%, the fluorinated solvent is preferably contained in a range of 95.00 mass% to 99.99 mass%, more preferably 99.00 mass% to 99.99 mass%, even more preferably 99.50 mass% to 99.99 mass%, and even more preferably 99.80 mass% to 99.99 mass%.

[0030] (Other additives) Other additives may include various additives known in the art, such as antioxidants, corrosion inhibitors, rust inhibitors, extreme pressure agents, solid lubricants, antiwear agents, thickeners, oiliness agents, anti-wear agents, structural stabilizers, colorants, detergent dispersants, color stabilizers, metal deactivators, viscosity index improvers, pour point depressants, and surfactants. One or more of these additives may be included. Furthermore, metal soaps and non-soaps may be added as solid lubricants. Examples of metal soaps include, but are not limited to, lithium soaps and calcium soaps, and examples of non-soaps include urea compounds, PTFE, and silica. Furthermore, fluorinated acrylic polymers and surfactants may be added to disperse these additives. The diluted lubricant of this embodiment can be composed of only a base oil, a fluorescent agent, and a fluorine-based solvent.

[0031] <Solubility> In this embodiment, it has been experimentally confirmed that both the base oil and the fluorescent agent can be appropriately dissolved when a low GWP fluorine-based solvent containing hydrochlorofluoroolefin is used. That is, in this embodiment, it is possible to prevent the base oil and the fluorescent agent from remaining undissolved in the diluted lubricant.

[0032] For example, when the solubility of fluorescent agents was confirmed using HFE, which was previously used as a fluorinated solvent, Fluorescent Agents B and C shown in Table 1 did not dissolve properly, leaving some residue, but when Cerefhin 1233Z or Amorea AS-300 was used as a fluorinated solvent, it was possible to dissolve all of Fluorescent Agents A to D. Furthermore, when Cerefhin 1233Z or Amorea AS-300 was used as a fluorinated solvent, it was possible to dissolve properly base oils containing at least one of synthetic hydrocarbon oil, silicone oil, and fluorinated oil.

[0033] <Lubricity> The diluted lubricant of this embodiment can provide excellent lubricity. The lubricity can be evaluated, for example, by the coefficient of friction measured by a reciprocating sliding test. For example, the static friction coefficient μs is 0.3 or less, preferably 0.25 or less. The dynamic friction coefficient μk is 0.1 or less, preferably 0.07 or less, and more preferably 0.06 or less.

[0034] The coefficient of friction decreased with the addition of some types of fluorescent agents, suggesting that the fluorescent agents contribute to improved lubricity. This tendency is seen in oxazole-based compounds, and the addition of fluorescent agent B (1,2-bis(5-methyl-2-benzoxazolyl)ethylene) is particularly favorable.

[0035] <Application> Although not limited thereto, the diluted lubricant of this embodiment is applied to sliding parts of home appliances, mechanical devices, etc. The sliding parts are made of materials such as metal, polytetrafluoroethylene (PTFE), polyethylene, polypropylene, polyacetal, etc. The diluted lubricant of this embodiment can be applied to lubricate these materials. After applying the diluted lubricant to the surface of a given component, a thin lubricating coating can be formed by evaporation of the solvent. <Method of manufacturing diluted lubricant> In the method for producing the diluted lubricant of this embodiment, the diluted lubricant containing the solvent, the fluorescent agent, and the base oil can be left to stand in an ultrasonic cleaner, or mixed and stirred. In the former case, it is preferable to leave it to stand for about 1 minute to 10 minutes, and then mix it by shaking it by hand, and repeat this operation several times. In the latter case, it can be stirred, for example, with a disperser. [Example]

[0036] The effects of the present invention will be explained below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0037] <Solubility experiment in fluorescent agents> Samples of Examples 1 to 8 were prepared with the formulations shown in Table 2. Fluorescent agents A to D used in the experiments are as shown in Table 1. Cerefine 1233Z or Amorea AS-300 was used as the fluorine-based solvent. In the experiments, one of fluorescent agents A to D was blended with one of Cerefine 1233Z and Amorea AS-300 to make a total of 100 mass %.

[0038] In the experiment, each of the fluorescent agents A to D was added to Cerefin 1233Z or Amorea AS-300, and the resulting sample was left to stand in an ultrasonic cleaner (EYELA's "ULTRASONIC CLEANER MUS-40D") for 10 minutes. The sample was then removed from the ultrasonic cleaner and mixed by hand. This procedure was repeated three times, after which the presence or absence of any remaining dissolved fluorescent agents A to D was checked visually. The experimental results are shown in Table 2 below.

[0039] [Table 2]

[0040] As shown in Table 2, it was confirmed that the fluorescent agents were dissolved in all of Examples 1 to 8. As such, it was found that by using Cerefhin 1233Z or Amorea AS-300 in a fluorine-based solvent, all of the fluorescent agents A to D can be dissolved. It was also found that the amount of fluorescent agent added is preferably about 0.01% by mass to 0.1% by mass.

[0041] Next, samples of Comparative Examples 1 to 4 were prepared with the formulations shown in Table 3. Fluorescent agents A to D used in the experiment are as shown in Table 1. Novec (registered trademark) 7100 (manufactured by 3M) was used as the fluorine-based solvent. In the experiment, any one of fluorescent agents A to D and Novec 7100 (manufactured by 3M) were blended to make 100 mass %. The experimental results are shown in Table 3 below.

[0042] In the experiment, each of the fluorescent agents A to D was added to Novec 7100 (manufactured by 3M), and the resulting sample was left to stand in an ultrasonic cleaner (EYELA's "ULTRASONIC CLEANER MUS-40D") for 10 minutes. The sample was then removed from the ultrasonic cleaner and mixed by hand by shaking. This procedure was repeated three times, after which the presence or absence of any remaining dissolved fluorescent agents A to D was checked visually. The experimental results are shown in Table 3 below.

[0043] [Table 3]

[0044] As shown in Table 3, when Novec 7100 (manufactured by 3M) was used as the fluorine-based solvent, fluorescent agent B and fluorescent agent C remained undissolved. Furthermore, in Comparative Examples 1 and 4, fluorescent agent A and fluorescent agent D were used, and in these cases, dissolution of the fluorescent agents was confirmed. However, the GWP of Novec 7100 (manufactured by 3M) was high at approximately 297, and both Cerefin 1233Z and Amorea AS-300 used in the examples had GWPs of less than 1. As described above, Tables 2 and 3 show that the fluorescent agent can be dissolved in a low GWP solvent.

[0045] <Solubility experiment in base oil> Samples of Examples 9 to 18 were prepared with the blends shown in Table 4. The base oils used in the experiments were Spectrasyn 4 (manufactured by ExxonMobil Corporation), KF96-20CS (manufactured by Shin-Etsu Chemical Co., Ltd.), and FOMBLIN (registered trademark) Y06 (manufactured by Solvay Specialty Polymers Japan Ltd.). In the experiments, one of the above three base oils was blended with one of Cerefhin 1233Z and Amorea AS-300 to make a total of 100 mass %.

[0046] In the experiment, each base oil was added to either Celefin 1233Z or Amorea AS-300, and the resulting sample was left to stand for 1 minute in an ultrasonic cleaner (EYELA's "ULTRASONIC CLEANER MUS-40D"). The presence or absence of residual base oil was then checked visually. The experimental results are shown in Table 4 below.

[0047] [Table 4]

[0048] As shown in Table 4, it was confirmed that the base oil was dissolved in all of Examples 9 to 18. As such, it was found that any base oil can be dissolved by using Cerefine 1233Z or Amorea AS-300 as a fluorine-based solvent. It was also found that the amount of base oil added is preferably about 1% by mass to 20% by mass.

[0049] Next, samples of Comparative Examples 5 to 8 were prepared with the blends shown in Table 5. The base oils used in the experiments were Spectrasyn 4 (manufactured by ExxonMobil Corporation), KF96-20CS (manufactured by Shin-Etsu Chemical Co., Ltd.), and FOMBLIN (registered trademark) Y06 (manufactured by Solvay Specialty Polymers Japan Ltd.). In the experiments, one of the above three base oils was blended with Novec 7100 (manufactured by 3M Company) to make up 100 mass %.

[0050] In the experiment, each base oil was added to Novec 7100 (manufactured by 3M) and the resulting sample was left to stand for 1 minute in an ultrasonic cleaner (EYELA's "ULTRASONIC CLEANER MUS-40D"). The presence or absence of residual base oil was then checked visually. The experimental results are shown in Table 5 below.

[0051] [Table 5]

[0052] As shown in Table 5, when Novec 7100 (3M) was used as the fluorine-based solvent, Spectrasyn 4 and KF96-20CS remained undissolved. FOMBLIN Y06 dissolved, but the GWP of Novec 7100 (3M) was much higher than that of Cerefin 1233Z and Amorea AS-300 used in the examples. As described above, Tables 4 and 5 show that the base oil can be dissolved in a low GWP solvent.

[0053] <Experiments on lubricity and fluorescent visibility> Next, samples of Examples 19 to 24 were prepared according to the formulations shown in Table 6. In the experiments, the base oil and fluorescent agent shown in Table 6 were added to Cerefin 1233Z or Amorea AS-300, and the samples were left to stand in an ultrasonic cleaner (EYELA's "ULTRASONIC CLEANER MUS-40D") for 10 minutes. The samples were then removed from the ultrasonic cleaner and mixed by hand by shaking. This operation was repeated three times. As shown in Table 6, the base oil, fluorescent agent, and fluorine-based solvent were blended so that the total amount was 100% by mass. For the lubrication experiments, a static and dynamic friction measuring device (model: TL201Tt, manufactured by Trinity Labs) was used. The experimental conditions were as follows: Test piece (fixed side): Polyacetal ball Test piece (sliding side): SPCC steel plate Load: 500g Test temperature: 25℃ Sliding speed: 10mm / sec Sliding width: 10mm Number of slides: 200

[0054] In the experiment, the diluted lubricants of Examples 19 to 24 were applied between the test piece (fixed side) and the test piece (sliding side), and after 5 minutes, a reciprocating sliding test was performed based on the above conditions, and the static friction coefficient μs and the dynamic friction coefficient μk were measured. Furthermore, each sample was irradiated with UV light to examine its luminescence (visibility). The experimental results are shown in Table 6.

[0055] [Table 6]

[0056] As shown in Table 6, the static friction coefficients μs of Examples 19 to 24 were found to be approximately 0.05 to 0.25. Furthermore, the dynamic friction coefficients μk were found to be approximately 0.025 to 0.06. These friction coefficients were found to be significantly reduced compared to when a reciprocating sliding test was performed without applying a diluted lubricant between the test pieces. Furthermore, the static friction coefficients μs and dynamic friction coefficients μk of Examples 19 to 24 were found to be values ​​that could satisfy the sliding characteristics required for actual products, and good lubrication was obtained. Furthermore, when the diluted lubricants of each example were irradiated with UV light to check for visibility by fluorescence, all examples emitted light, and good visibility was obtained.

[0057] Next, samples of Comparative Examples 9 to 11 were prepared with the formulations shown in Table 7. In the experiment, the base oils shown in Table 7 were added to Cerefin 1233Z or Amorea AS-300, and the samples were left to stand in an ultrasonic cleaner (EYELA's "ULTRASONIC CLEANER MUS-40D") for 10 minutes. The samples were then removed from the ultrasonic cleaner and mixed by hand by shaking. This operation was repeated three times. As shown in Table 7, the base oils and fluorinated solvents were blended so that the total amount was 100% by mass.

[0058] No fluorescent agent was added to Comparative Examples 9 to 11. As shown in Table 7 below, for the lubricity test, a blank sample was also shown, in which a reciprocating sliding test was performed without applying any diluted lubricant between the test pieces.

[0059] [Table 7]

[0060] As shown in Table 7, the reciprocating sliding tests of Comparative Examples 9 to 11 all showed low static friction coefficients μs and dynamic friction coefficients μk, and good lubrication was achieved. However, none of the Comparative Examples contained a fluorescent agent, and it was found that visibility under UV irradiation was poor.

[0061] Comparing the Examples in Table 6 with the blank in Table 7, it was found that applying the diluted lubricant of this Example not only provided good visibility but also significantly improved lubrication. It is also believed that the type of fluorescent agent may also contribute to improved lubrication. For example, when fluorescent agent B was added, both the static friction coefficient μs and the dynamic friction coefficient μk were found to be improved compared to when no fluorescent agent was added. Furthermore, when fluorescent agent D was used, the static friction coefficient μs was slightly higher than when no fluorescent agent was added, but the dynamic friction coefficient μk was almost the same. [Industrial Applicability]

[0062] The diluted lubricant of the present invention can achieve a lower GWP than HFEs and HFCs while maintaining excellent solubility and lubricity, thereby reducing the environmental impact and making it suitable for use in sliding parts of home appliances, mechanical devices, etc.

Claims

1. Contains a base oil, a fluorescent agent, and a fluorine-based solvent, the fluorine-based solvent is capable of dissolving the base oil and the fluorescent agent, and includes a hydrochlorofluoroolefin; The dilution type lubricant is characterized in that the fluorescent agent contains an oxazole-based or coumarin-based agent.

2. 2. The diluted lubricant according to claim 1, wherein the fluorine-based solvent has a GWP of less than 30.

3. 3. The diluted lubricant according to claim 1, wherein the base oil contains at least one of a synthetic hydrocarbon oil, a silicone oil, and a fluorinated oil.

4. 4. The diluted lubricant according to claim 3, wherein the fluorine-based solvent is contained in an amount of 60% by mass or more and 99.5% by mass or less when the sum of the base oil and the fluorine-based solvent is 100% by mass.

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