Solvent-based water-based lubricant composition

Abstract

To provide a solvent-diluted water-based lubricant composition capable of effectively dispersing hydrophobic base oils, such as perfluoropolyether oils and synthetic hydrocarbon oils, constituting grease in water as a solvent, and capable of forming a uniform grease film and imparting good lubricity. [Solution] The present invention provides a solvent-diluted water-based lubricating composition comprising: water as a solvent; a grease containing a base oil dispersed in the water solvent and containing one or more oils selected from perfluoropolyether oils and synthetic hydrocarbon oils, a thickener, and an additive containing a polymeric polysaccharide.

Description

[Technical field]

[0001] The present invention relates to a solvent-diluted water-based lubricant composition obtained by dispersing grease in water. [Background technology]

[0002] Greases are often classified according to the base oil and thickener. Among them, greases made by thickening perfluoropolyether oil with fluorine-based polymers such as polytetrafluoroethylene or inorganic thickeners are called fluorine greases. Liquid lubricants made by dispersing such fluorine greases in fluorine-based solvents such as hydrofluoroethers and hydrofluorocarbons are called solvent-diluted fluorine-based lubricants.

[0003] In contrast to liquid solvent-diluted fluorine-based lubricants dispersed in a fluorine-based solvent, liquid lubricants in which grease is dispersed in water using water as a solvent are called solvent-diluted water-based lubricants.

[0004] Fluorine grease has many excellent functions such as lubricity, heat resistance, oxidation stability, resistance to resins and rubber, low dust generation, and chemical resistance due to the excellent performance derived from its base oil. Fluorine grease is often used in precise and delicate parts of home appliances. Some home appliances can be used for more than 10 years without maintenance, and fluorine grease can fully satisfy the required specifications due to its multifunctionality. On the other hand, fluorine grease is expensive. Therefore, it is required to use it in as thin a layer as possible within the range where it does not cause problems in use.

[0005] The solvent-diluted fluorine-based lubricant can form a thin fluorine grease film by volatilizing the solvent after application. Therefore, the amount of fluorine grease used can be reduced, and costs can be reduced. In addition, since the solvent-diluted lubricant is a low-viscosity liquid lubricant, it can be applied by methods such as dipping and brushing, which can improve work efficiency and productivity, and can be applied relatively easily to parts with complex structures. Furthermore, since the solvent-diluted lubricant has excellent fluidity, it is easy to control the dispersibility of the fluorine grease in the solvent by using additives as necessary, and the fluorine grease can be appropriately distributed. As a result, the fluorine grease film after drying becomes a thin and uniform film with little variation, and as a result, the production cost of parts on which the fluorine grease film is formed can be reduced.

[0006] In recent years, there has been a movement to regulate PFAS (perfluoroalkyl compounds and polyfluoroalkyl compounds, a general term for organic fluorine compounds in which multiple fluorine atoms are bonded to an alkyl chain). Therefore, in solvent-diluted fluorine-based lubricants, replacements are required for perfluoropolyether oil as a base oil, polytetrafluoroethylene as a solid lubricant, and hydrofluoroether and hydrofluorocarbon as fluorine-based solvents. In particular, there is an urgent need to replace fluorine solvents that are contained in large amounts in the composition.

[0007] For example, Patent Document 1 discloses a technology of a lubricant composition containing a lubricating oil, a wax, melamine cyanurate, an anionic surfactant, and an aqueous solvent. The technology disclosed in Patent Document 1 claims that by using an anionic surfactant in a lubricant composition containing an aqueous solvent, it is possible to reduce settling and separation of components such as solid lubricants without using expensive fluorine-based solvents and fluorine oils.

[0008] However, even with the technology disclosed in Patent Document 1, for example when a highly hydrophobic lubricating oil is used, the hydrophobic oil may not be sufficiently dispersed in the lubricant composition, and as a result, the grease film formed may not be uniform, making it difficult to ensure sufficient lubricity. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 2008-88297 A Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been proposed in view of the above-mentioned conventional circumstances, and has an object to provide a solvent-diluted water-based lubricant composition comprising grease dispersed in water, capable of forming a uniform grease film and imparting good lubricity. [Means for solving the problem]

[0011] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result, have found that in a solvent-diluted water-based lubricant composition in which grease is dispersed in water as a solvent, by adding a polymeric polysaccharide as an additive, the hydrophobic base oil constituting the grease can be effectively dispersed in water, thereby completing the present invention.

[0012] (1) A first aspect of the present invention is a solvent-diluted water-based lubricating composition comprising: a water solvent; a grease containing a base oil dispersed in the water solvent and containing at least one oil selected from perfluoropolyether oils and synthetic hydrocarbon oils, a thickener; and an additive containing a polymeric polysaccharide.

[0013] (2) A second aspect of the present invention is the solvent-diluted water-based lubricant composition according to the first aspect of the present invention, wherein the polymeric polysaccharide forms a network structure in water through hydrogen bonds.

[0014] (3) A third aspect of the present invention is a solvent-diluted water-based lubricant composition according to the first or second aspect of the present invention, wherein the thickener comprises one or more selected from the group consisting of polytetrafluoroethylene, melamine cyanurate, and polyethylene solid powder.

[0015] (4) A fourth aspect of the present invention is a solvent-diluted water-based lubricant composition according to any one of the first to third aspects, further comprising a surfactant.

[0016] (5) A fifth aspect of the present invention is a solvent-diluted water-based lubricant composition according to any one of the first to fourth aspects of the present invention, wherein the grease is a fluorine grease and the solvent does not contain a fluorine-based solvent. Effect of the Invention

[0017] According to the present invention, it is possible to provide a solvent-diluted water-based lubricant composition capable of forming a uniform grease film and imparting good lubricity. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] A specific embodiment of the present invention (hereinafter, referred to as the present embodiment) will be described in detail below. Note that the present invention is not limited to the following embodiment, and various modifications are possible without departing from the gist of the present invention.

[0019] 1. Configuration of solvent-diluted water-based lubricant composition The lubricant composition according to the present embodiment is a solvent-diluted water-based lubricant composition in which grease is dispersed in water as a solvent. When the solvent-diluted water-based lubricant composition is applied to a part made of resin, metal, or the like, the water as a solvent is volatilized and removed by drying, and a grease coating is formed on the surface of the part to be coated.

[0020] The grease constituting the solvent-diluted water-based lubricant composition contains a base oil and a thickener. The base oil constituting the grease is hydrophobic and contains at least one oil selected from perfluoropolyether oil and synthetic hydrocarbon oil. The grease is, for example, a fluorine grease.

[0021] The solvent-diluted water-based lubricant composition according to the present embodiment is characterized in that it contains an additive containing a polymeric polysaccharide.

[0022] In the solvent-diluted water-based lubricant composition, the state in which the grease is "dispersed" in the water as the solvent also means the state in which the grease is dissolved in the water. In addition, in the solvent-diluted water-based lubricant composition, water is used as the solvent with a large content ratio, and no fluorine-based solvent is contained.

[0023] (1) Grease The grease contains at least a base oil and a thickener. In the solvent-diluted water-based lubricant composition, the grease is dispersed in water, which is a solvent. The grease may contain components other than the base oil and the thickener.

[0024] (1-1) Base oil The base oil is a component of the grease and is a hydrophobic base oil selected from perfluoropolyether oil and synthetic hydrocarbon oil. The base oil may be one type alone or two types may be used in combination. In particular, from the viewpoint of PFAS regulations, it is more preferable to use synthetic hydrocarbon oil. In addition to these hydrophobic base oils, other types of base oils may be included. For example, other base oils include polyalkylene glycol synthetic lubricating oils.

[0025] (Perfluoropolyether oil) Fluorine oils are broadly classified into those having a side-chain molecular structure and those having a straight-chain molecular structure, and are selected from the viewpoints of lubrication mechanism, cost, required lubricity, etc. Perfluoropolyether oils are not particularly limited, but examples thereof include those having structures represented by the following general formulas (i) to (iv).

[0026] F-(CFCF3-CF2-O-) n -CF2-CF3··(i) (Note that n in formula (i) is 0 or a positive integer.) CF3-(O-CFCF3-CF2) p -(O-CF2-) q -O-CF3··(ii) (Note that p and q in formula (ii) are each independently 0 or a positive integer.) F-(CF2-CF2-CF2-O-) r -CF2-CF3 (iii) (Note that r in formula (iii) is 0 or a positive integer.) CF3-(O-CF2-CF2-) s -(O-CF2-) t -O-CF3··(iv) (Note that s and t in formula (iv) are each independently 0 or a positive integer.)

[0027] Specifically, for example, commercially available products such as the Krytox series (manufactured by DuPont), Fomblin Y series (manufactured by Solvay Specialty Polymers Japan), Fomblin M series (manufactured by Solvay Specialty Polymers Japan), Fomblin W series (manufactured by Solvay Specialty Polymers Japan), Fomblin Z series (manufactured by Solvay Specialty Polymers Japan), Demnum S series (manufactured by Daikin Industries, Ltd.), and PT series (manufactured by Nicca Chemical Co., Ltd.) can be used.

[0028] As the perfluoropolyether oil, those having the above-mentioned structure can be mentioned. Among them, those having a kinetic viscosity of 15 mm at 40° C. 2 / s~600mm 2 It is preferable to use one in the range of / s.

[0029] (Synthetic hydrocarbon oil) Examples of synthetic hydrocarbon oils include alpha (α)-olefins produced from raw materials such as ethylene, propylene, butene, and derivatives thereof, which are polymerized alone or in combination of two or more kinds (poly-α-olefins).Preferable examples of α-olefins include those having 6 to 14 carbon atoms.

[0030] Specific examples of synthetic hydrocarbon oils include poly-α-olefins (PAOs), which are oligomers of 1-decene or 1-dodecene, polybutenes, which are oligomers of 1-butene or isobutylene, and co-oligomers of ethylene or propylene with α-olefins, etc. In addition, alkylbenzenes and alkylnaphthalenes can also be used.

[0031] (Polyalkylene glycol synthetic lubricant) Polyalkylene glycol synthetic lubricants are available in water-soluble and oil-soluble types, and the water-soluble types are used in water-based hydraulic oils, cutting oils, cleaning agents, etc. Among them, polyethylene glycol has a wide range of molecular weights, with a number average molecular weight of about 200 to 20,000.

[0032] (1-2) Thickener The thickener is not particularly limited, but examples thereof include solid lubricants such as polytetrafluoroethylene, melamine cyanurate, and polyethylene solid powder, and these can be used alone or in combination of two or more. Among these, from the viewpoint of PFAS regulations, it is preferable to use melamine cyanurate or polyethylene solid powder.

[0033] (Polytetrafluoroethylene) Either unbaked or baked polytetrafluoroethylene (PTFE) can be used depending on the lubricating properties and the coating properties of the grease. Polytetrafluoroethylene has a heat resistance of 250°C to 260°C, exhibits low friction even under severe lubricating conditions, and can extend the life of machinery.

[0034] In addition, solid lubricants such as unsintered polytetrafluoroethylene are amorphous, have a large specific surface area and oil absorption, and can develop grease viscosity even in small amounts, so they have been widely used in lubricants in the past. However, such solid lubricants are easily deformed by shearing during lubrication, so they can be deformed by mechanical shearing when dispersed in a solvent, and the viscosity can become too high for fine parts. On the other hand, solid lubricants such as sintered polytetrafluoroethylene have a particle shape close to a sphere, have a small oil absorption, and are not easily deformed even when shearing is applied. Therefore, when dispersed in a solvent, the viscosity of the grease is not easily changed even when mechanical shearing occurs, and adhesion between parts can be effectively prevented.

[0035] (Melamine Cyanurate) Melamine cyanurate has a graphite structure and exhibits lubricity comparable to that of polytetrafluoroethylene. Melamine cyanurate also has a heat resistance of 250°C to 300°C, produces inert gas during combustion, and can dilute the oxygen concentration, making it flame-retardant.

[0036] (polyethylene) Various polyethylene solid powders have been developed that have properties similar to those of polytetrafluoroethylene, and they exhibit effects such as improved slip properties (friction properties) and scratch resistance, as well as improved Taber abrasion resistance and friction resistance.

[0037] (2) Additives (High molecular weight polysaccharide) The solvent-diluted water-based lubricant composition according to the present embodiment is characterized by containing an additive containing a polymeric polysaccharide. By containing the polymeric polysaccharide, the hydrophobic base oil constituting the grease can be highly dispersed in the water solvent to form a uniform composition. This also allows the formation of a uniform grease film, providing good lubricity.

[0038] In addition, the phrase "highly dispersible in water" due to the action of polymeric polysaccharides means that the hydrophobic base oil is broken down into fine particles in water and dispersed in the water where they are fixed. In this way, polymeric polysaccharides make it possible to effectively disperse highly hydrophobic base oil in water, which is a solvent.

[0039] As the polymeric polysaccharide, one that forms a network structure by hydrogen bonding in water is used. The polymeric polysaccharide has the property of being stable by hydrogen bonding when no shear is applied, and flowing when shear is applied. In the solvent-diluted water-based lubricant composition, the polymeric polysaccharide forms a mesh-like network structure in the solvent water, and due to this network structure, it exhibits unique rheological properties such as very high pseudoplastic fluidity. In addition, due to the network structure, it has the effect of stabilizing oil droplets and fine particles of the base oil. In the solvent-diluted water-based lubricant composition according to this embodiment, such an action of the polymeric polysaccharide makes it possible to highly disperse the hydrophobic base oil that constitutes the grease in the solvent water.

[0040] As described above, the polymeric polysaccharide is not particularly limited as long as it forms a network structure in water by hydrogen bonding, but specific examples include cellulose polymers (methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose, methylhydroxypropyl cellulose, etc.), starch, starch derivatives, dextrin, alginic acids, agar, guar gum, locust bean gum, tara gum, fenugreek gum, tamarind gum, glucomannan, pectin, xanthan gum, gellan gum, κ-carrageenan, ι-carrageenan, λ-carrageenan, furcellan, cassia gum, curdlan, queen seed, gum arabic, succinoglucan, glycosaminoglycan, etc. Polymeric polysaccharides may be used alone or in combination of two or more kinds.

[0041] As the polymeric polysaccharide, for example, Rheocrysta I-2SX manufactured by Daiichi Kogyo Seiyaku Co., Ltd. can be used. Rheocrysta I-2SX is an additive in which cellulose nanofibers (CNF) are dispersed in water, and can be easily diluted.

[0042] The content of the polymeric polysaccharide is not particularly limited, but is preferably in the range of 0.05% by mass to 1.5% by mass, and more preferably in the range of 0.1% by mass to 1.0% by mass, relative to 100% by mass of the composition. In particular, by having the content of the polymeric polysaccharide in the range of 0.1% by mass to 1.0% by mass, the composition can be highly dispersed in water, which is a solvent, regardless of the type of base oil, and can be made into a good solvent-diluted water-based lubricant composition without impairing the applicability to the surface of the part or the like, which is the object to be coated.

[0043] (Surfactant) In the solvent-diluted water-based lubricant composition according to the present embodiment, a surfactant can be contained, although this is not essential. By containing a surfactant, the dispersibility of the solid powder constituting the grease can be further improved. In addition, the adhesion of the grease film to the substrate made of resin can be improved, and the distribution of the grease film after coating and drying can be made uniform.

[0044] The surfactant is not particularly limited as long as it dissolves or disperses in water, regardless of the type of base oil and thickener that constitute the grease. The surfactant may be an ionic surfactant such as a cationic surfactant, an anionic surfactant, or an amphoteric surfactant, or a nonionic surfactant, but it is more preferable to use a nonionic surfactant. More specifically, for example, a polyglycerin fatty acid ester compound or a polyoxyethylene alkyl ether can be used.

[0045] Moreover, from the viewpoint of improving the dispersibility of the solid component in water, the surfactant has a high HLB value, for example, preferably 13 or more, more preferably 14 or more. Moreover, from the viewpoint of improving the adhesion to the resin when the coated object is a resin part or the like, the surfactant has a low HLB value, for example, preferably 13 or less, more preferably 11 or less. In this way, by using surfactants with different HLB values ​​for different purposes, the dispersibility in water, which is a solvent, and the adhesion to the resin can be controlled, and a lubricant composition that exhibits superior lubricity can be obtained.

[0046] (3)Water In the solvent-diluted water-based lubricant composition according to the present embodiment, water is a solvent that dilutes and disperses the above-mentioned grease components to form a solvent-diluted lubricant composition. When the solvent-diluted water-based lubricant composition is applied to a part or the like as a coating object and the water as a solvent is evaporated by drying or the like, a grease coating is formed on the coating surface.

[0047] Here, the solvent-diluted water-based lubricant composition according to the present embodiment does not contain a fluorine-based solvent as a solvent. As described above, by containing a polymeric polysaccharide as an additive, the hydrophobic base oil constituting the grease can be dispersed well even if the solvent is water.

[0048] The water is not particularly limited, and may be tap water, purified water, distilled water, pure water, etc. In addition, the water may contain an aqueous solvent such as a monohydric alcohol.

[0049] The content of water as a solvent is not particularly limited, but is preferably about 85% to 95% by mass, and more preferably about 90% to 94% by mass, relative to 100% by mass of the composition.

[0050] (4) Other ingredients In addition, in the solvent-diluted water-based lubricant composition according to the present embodiment, in addition to the above-mentioned components, various components can be contained within a range that does not impair the effects of the components. For example, various components such as water-based solvents (alcohols: ethanol, isopropanol, etc.), antifoaming agents, metal corrosion inhibitors, and rust inhibitors can be contained.

[0051] 2. State of Solvent-Diluted Water-Based Lubricant Composition (Regarding Particle Size) As described above, the solvent-diluted water-based lubricant composition according to the present embodiment is a composition in which grease is dispersed in water, which is a solvent. In particular, by including an additive containing a polymeric polysaccharide, the base oil constituting the grease can be dispersed well. Thus, the solvent-diluted water-based lubricant composition is a mixture in which the base oil and solid lubricant constituting the grease are dispersed in the water, which is a solvent. Therefore, in order to uniformly apply the composition to the surface of a part or the like, which is a coating object, and form a uniform grease film, it is preferable that the particle diameter of the oil droplets and solid lubricant dispersed in the water is smaller.

[0052] Specifically, in the solvent-diluted water-based lubricant composition, the particle size of the oil droplets and solid lubricant dispersed in the water as the solvent is preferably less than 50 μm in average particle size, more preferably less than 30 μm. Thus, in the solvent-diluted water-based lubricant composition according to the present embodiment, the oil droplets made of the hydrophobic base oil and the solid lubricant components are highly dispersed in the water as the solvent, with sizes that are barely visible to the naked eye.

[0053] The average particle size of the oil droplets and solid lubricant dispersed in water can be measured, for example, by using a known laser diffraction particle size distribution measuring device.

[0054] 3. Method for producing solvent-diluted water-based lubricant composition The lubricant composition according to the present embodiment can be manufactured by a known method. Specifically, for example, the solvent water and the additive polymer polysaccharide are weighed in a container, and while stirring by a known stirring method, a hydrophobic base oil is added and dispersed. In addition, a dispersion in which a thickener is dispersed in water, a surfactant, and various other components as necessary are added and dispersed. This makes it possible to obtain a solvent-diluted water-based lubricant composition in which grease is dispersed in water as a solvent.

[0055] Dispersion of base oil in water or water in a thickener can be carried out using a wet stirring / dispersion treatment device such as a propeller agitator, dissolver, homomixer, Dispermat, Star Mill, Dyno Mill, Agitator Mill, Clear Mix, or Filmix.

[0056] The order in which each component is added and mixed is not limited to the above-mentioned order. Depending on the dispersion capacity of the stirring / dispersing device used, each component may be added and mixed at the same time, or only some of the components may be mixed and stirred at the same time. EXAMPLES

[0057] The present invention will be described in more detail below by showing specific examples, but the present invention is not limited to the following examples in any way.

[0058] <Production of solvent-diluted water-based lubricant composition> In Examples 1 to 7 and Comparative Examples 1 to 5, solvent-diluted water-based lubricant compositions were produced by dissolving the greases in the blending ratios shown in Table 1 below in water as a solvent. Note that in Table 1, the blending amounts are shown in "mass %", and the following components were used to make up the compositions.

[0059] [component] (Base oil) Perfluoropolyether oil: PT-02 (manufactured by Nicca Chemical Co., Ltd.) Synthetic hydrocarbon oil: Spectrasyn 4 (manufactured by Exxon Mobil) (Thickener) Polytetrafluoroethylene: PTFE dispersion (60% product) (manufactured by Seishin Enterprise Co., Ltd.) Melamine cyanurate: MC-6000 (Nissan Chemical Co., Ltd.) Polyethylene: MaxWax70 (Shamrock, USA) (Additives) Cellulose nanofiber: Rheocrysta I-2SX (containing 2% polymeric polysaccharides) (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) (Surfactant) Polyglycerol fatty acid ester (lauric acid ester) (HLB value 14.7): SY Glystar ML-750 (manufactured by Sakamoto Pharmaceutical Co., Ltd.) Polyglycerol fatty acid ester (lauric acid ester) (HLB value 10.4): SY Glystar ML-310 (manufactured by Sakamoto Pharmaceutical Co., Ltd.) (solvent) Water: Tap water

[0060] [Manufacturing procedure] (Preparation of Water Dispersion of Thickener) First, for the thickener, melamine cyanurate or polyethylene, an aqueous dispersion was prepared in which the ratio of the thickener to the surfactant [polyglycerol fatty acid ester (HLB value: 14.7)] was the blending ratio shown in Table 1 below, and the solid content was 9.2%. Specifically, water and a surfactant were added to a container and stirred, and then the thickener was added and pre-dispersed using a dissolver. Then, a predetermined amount of zirconia beads was added to the container, which was then sealed and shaken with a paint shaker to prepare an aqueous dispersion of the thickener. In addition, a commercially available product was used for the aqueous dispersion of polytetrafluoroethylene, which is the thickener.

[0061] (Preparation of Solvent-Diluted Water-Based Lubricant Composition) The solvent water and polymeric polysaccharide were weighed and placed in a container, and the mixture was highly dispersed using a dissolver. A base oil was added thereto to further disperse the mixture. Next, the water dispersion of the thickener, a surfactant [polyglycerol fatty acid ester (HLB value: 10.4)], and water were added and mixed by stirring. This produced a solvent-diluted water-based lubricant composition in which the grease was dispersed in water.

[0062] In Reference Example 1, a conventional solvent-diluted fluorine-based lubricant composition in which grease is dispersed in a fluorine-based solvent was used.

[0063] Evaluation The prepared solvent-diluted water-based lubricant compositions were subjected to the following evaluations.

[0064] [Dispersibility of base oil in solvent] The dispersibility in water, which is a solvent for the base oil constituting the grease, was evaluated. Specifically, in the examples, as shown in Table 1, water and polymeric polysaccharide were weighed into a glass bottle, and then uniformly dispersed in a vortex mixer, and the base oil was added and stirred in a vortex mixer to confirm the dispersibility. In the comparative examples, water and surfactant were weighed into a glass bottle, and uniformly dispersed or dissolved in a vortex mixer, and then the base oil was added and stirred in a vortex mixer to confirm the dispersibility. Then, when the presence of the base oil could not be visually confirmed, it was evaluated as "◎" which means that the grease was uniformly dispersed, and when the presence of the base oil was visually confirmed at the bottom of the glass bottle or on the liquid surface, it was evaluated as "×" which means that the grease was not uniformly dispersed.

[0065] [PFAS substitutability] The composition of solvent-diluted water-based lubricant compositions was evaluated on whether the solvent was replaced with a non-PFAS material. If the solvent was water and did not contain a fluorine-based solvent, it was rated as "◎", and if the solvent contained a fluorine-based solvent, it was rated as "×".

[0066] [Evaluation of coating properties] The applicability of the solvent-diluted water-based lubricant composition to resin was evaluated. Specifically, the solvent-diluted water-based lubricant composition was charged into a 50 mL glass beaker, and a POM plate (40 x 50 x t2 mm) whose surface had been washed with ethanol was dipped about halfway into the composition, and then removed from the liquid surface and dried. If the composition was applied to the resin well, it was rated as "◎", if there was some repellency but the composition was applied without problems, it was rated as "○", if the composition was applied but repellency was confirmed, it was rated as "△", and if the composition could not be applied, it was rated as "×".

[0067] [Evaluation of lubricity] The lubricity of the coating formed by the solvent-diluted water-based lubricant composition was evaluated. Specifically, the friction coefficient was measured under the following test conditions using a friction player (manufactured by Rhesca Co., Ltd.) as a tester. That is, the solvent-diluted water-based lubricant composition was applied to a POM plate (40 x 50 x t2 mm) by dipping, dried, and then an ABS ball (3 / 8 inch) was placed on the upper jig, a 500 gf weight was placed on it, and the friction coefficient was measured when the plate was slid for 30 minutes. (Conditions for measuring coefficient of friction) Evaluation test machine: Friction Player Test pieces: ABS ball (upper side), POM plate (lower side) Surface contact form: point contact Load: 500gf Sliding mode: Sliding Sliding speed: 50mm / s Sliding time: 30 minutes

[0068] As a result of the measurements, if the average friction coefficient over 30 minutes was less than 0.1, the lubricity was evaluated as good (◎); if the friction coefficient was 0.1 or more but less than 0.15, the lubricity was evaluated as good (○), meaning that the material could be used under certain conditions; and if the friction coefficient was 0.2 or more, the lubricity was evaluated as poor (×).

[0069] ≪Results≫ The compositions of the solvent-diluted water-based lubricant compositions in the examples and comparative examples are shown in Table 1 below, along with the results of the above-mentioned evaluation tests. In addition, the evaluation results for a conventional solvent-diluted fluorine-based lubricant composition are also shown as Reference Example 1.

[0070] [Table 1]

[0071] From the results shown in Table 1, it was found that in the compositions of Examples 1 to 5, in which polymeric polysaccharides were blended as additives, the hydrophobic base oil constituting the grease was well dispersed in the water solvent, resulting in a uniform lubricant composition. As a result, the grease film formed was also uniform, and showed good lubricity.

[0072] On the other hand, in Comparative Examples 1 to 5 in which no polymeric polysaccharide was blended, the hydrophobic base oil was not dispersed in the solvent water, and a uniform lubricant composition was not obtained. Also, from the results of Comparative Examples 2, 4, and 5, it can be seen that although various surfactants were blended, the hydrophobic base oil could not be dispersed in the solvent water.

Claims

1. Water as a solvent; a grease dispersed in the water solvent, the grease containing a base oil containing at least one oil selected from the group consisting of perfluoropolyether oil and synthetic hydrocarbon oil, and a thickener; An additive including a polymeric polysaccharide; A solvent-diluted water-based lubricating composition comprising:

2. The polymeric polysaccharide forms a network structure in water through hydrogen bonds. The solvent-diluted water-based lubricant composition according to claim 1.

3. The thickener includes at least one selected from the group consisting of polytetrafluoroethylene, melamine cyanurate, and polyethylene solid powder. The solvent-diluted water-based lubricant composition according to claim 1 or 2.

4. Further containing a surfactant, The solvent-diluted water-based lubricant composition according to claim 1 or 2.

5. The grease is a fluorine grease, The solvent does not include a fluorine-based solvent. The solvent-diluted water-based lubricant composition according to claim 1 or 2.

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