JP4880243B2 - Lubricant composition - Google Patents

Description

  The present invention relates to a lubricant composition, and more particularly to a lubricant composition in which a lubricant film having a low coefficient of friction and a long life is formed after application to an application site and volatilization of a diluting solvent. More particularly, the present invention relates to a lubricant composition used for sliding parts between resin parts such as audio / video equipment and information equipment, resin parts and metal parts, or metal parts.

Conventionally, in order to apply a lubricating film, a non-flammable fluorine-based solvent is used as a carrier, applied to a sliding portion of a target component, and dried to form a semi-solid lubricating film. Yes. In this case, since a fluorine-based solvent is used, the usable lubricating oil is limited, and in many cases, a fluorine oil such as perfluoropolyether has been used. However, since fluorine oil is expensive, a cheaper one is desired.
Further, a solid lubricant is often added to the lubricant composition to be used, and for example, polytetrafluoroethylene (PTFE) has been used as the solid lubricant. However, the specific gravity of PTFE is about 2.2, which is larger than the specific gravity of the solvent, and has a disadvantage that it easily settles.
The present inventors have previously found that sedimentation can be effectively suppressed by adding a wax that is compatible with the lubricating oil used in the lubricant composition and coating the solid lubricant with the wax (Patent Literature). 1). As a result, the problem of solid lubricant settling has been reduced, but since the solvent used is a fluorinated solvent, there is a problem that the lubricating oil that can be used is limited, and the fluorinated solvent and the fluorinated oil are both expensive. This problem has not been solved.
In order to solve this problem, the present inventors further developed a lubricant composition containing a lubricating oil, a wax, a solid lubricant, a surfactant and water (Patent Document 2).
On the other hand, in home appliances, lubricants are used for components such as hinges, damping, resin gears, and open / close trays. For home appliances, PC resin, ABS resin, PC / ABS alloy, and the like are often used from the viewpoint of impact resistance and dimensional accuracy, and the lubricant to be used is required not to be affected.

JP2002-20775 JP2004-43537

An object of the present invention is to provide a lubricant composition that can prevent or reduce the settling / separation of a solid lubricant or the like without using an expensive fluorinated solvent and fluorinated oil, is easy to handle and is economical. Is to provide.
Another object of the present invention is to provide a lubricant composition that is less likely to become familiar with water after drying, is less likely to be washed away by water, and can form a coating effective in preventing rust.
It is a further object of the present invention to provide a lubricant composition that is particularly excellent in the lubrication of resin parts and that is excellent in resin resistance, coating properties, and drying properties.
Another object of the present invention is to provide a lubricious coating film formed from the lubricant composition.
Still another object of the present invention is to provide a sliding member having the lubricating coating.

As a result of intensive research to solve the above problems, the present inventors have used water or a mixture of water and a water-soluble organic solvent as a carrier for a lubricant composition containing a lubricating oil, a wax and a solid lubricant. Further, it was found that an excellent lubricant composition can be obtained by adding an anionic surfactant, and the present invention has been completed.
The present invention provides the following lubricant composition, a lubricious film formed from the lubricant composition, and a sliding member having the lubricious film.
1. A lubricant composition comprising a lubricant, a wax, a solid lubricant, an anionic surfactant and an aqueous solvent.
2. The lubricant composition according to claim 1, wherein the total amount of the lubricating oil, wax, solid lubricant and anionic surfactant is 1.0 to 50.0% by mass, and the balance is an aqueous solvent.
3. The lubricant composition according to claim 1 or 2, wherein the lubricating oil is at least one selected from the group consisting of polyalphaolefin oil, fatty acid ester oil, carbonate ester oil, alkyldiphenyl ether oil, alkylbenzene oil, and silicone oil.
4). The lubricant composition according to any one of claims 1 to 3, wherein the wax is at least one selected from the group consisting of montan wax and derivatives thereof, petroleum wax and polyethylene wax.
5. The lubricant composition according to any one of claims 1 to 4, wherein the solid lubricant is at least one selected from the group consisting of a fluorine-based polymer powder and a fluorine-containing copolymer powder.
6). The lubricant composition according to claim 5, wherein the solid lubricant is a polytetrafluoroethylene powder.
7). The lubricant composition according to any one of claims 1 to 6, wherein the aqueous solvent is water or a mixture of 50% by mass or more water and 50% by mass or less water-soluble organic solvent.
8). The lubricant according to any one of claims 1 to 7, wherein the anionic surfactant is at least one selected from the group consisting of carboxylate, sulfonate, sulfate ester salt, and phosphate ester salt. Composition.
9. A lubricious coating film formed from the lubricant composition according to claim 1.
10. A sliding member having the lubricating coating according to claim 9.

  The lubricant composition of the present invention can form a lubricious film that exhibits a lubricating performance higher than that of conventional products using inexpensive lubricating oil and water without using expensive fluorine-based solvents and fluorine oil. it can. The lubricant composition of the present invention is easy to handle because there is little sedimentation / separation of solid lubricants during storage, and is excellent in lubrication performance, resin resistance, applicability, and drying properties, especially for lubrication between resin parts. It can be preferably used.

The lubricating oil used in the lubricant composition of the present invention is not particularly limited, and examples thereof include ester-based, mineral oil-based, synthetic hydrocarbon-based, fluorine-based, and silicon-based. Among them, polyalphaolefin oil, fatty acid ester oil (for example, ester oil of fatty acid containing polybasic acid and aliphatic and polyhydric alcohol), carbonate oil, alkyl diphenyl ether oil, alkylbenzene oil, silicone oil It is preferable that at least one selected. From the viewpoint of resin resistance, polyalphaolefin oil and carbonate ester oil are preferable, and from the viewpoint of price, polyalphaolefin oil is preferable. Specific examples of lubricating oil include polyalphaolefin oil and various long chain aliphatics. Examples include alcohol carbonates such as dialkyl carbonates (the alkyl group preferably has 8 to 24 carbon atoms).
The content of the lubricating oil in the lubricant composition of the present invention is preferably 0.1 to 50.0% by mass, more preferably 0.5 to 35.0% by mass, and most preferably 1.0 to 20%. 0% by mass.

In the lubricant composition of the present invention, it is necessary to use a wax that is reasonably compatible with the lubricating oil used. A wax that is dissolved or uniformly dispersed in a lubricating oil at a temperature near its melting point and that precipitates uniformly after cooling is suitable.
The wax is selected in relation to the lubricating oil to be used, and examples thereof include petroleum waxes, various paraffin waxes having different melting points, various microcrystalline waxes, montan waxes and derivatives thereof, and waxes such as polyethylene waxes. Among these, it can use individually or in combination of 2 or more types. Since polyalphaolefin oil and carbonated ester oil are preferable as the lubricating oil to be used, the wax should also be at least one selected from the group consisting of ester-based montan wax and derivatives thereof, petroleum-based wax and polyethylene-based wax. Is preferred. Also preferred are ester-modified or partially saponified synthetic waxes such as ester montan wax, partially saponified montan wax, and partially saponified polyethylene wax.
The wax content in the lubricant composition of the present invention is preferably 0.05 to 20.0% by mass, more preferably 0.1 to 10.0% by mass, and most preferably 1.0 to 5.0. % By mass.
The mass ratio between the lubricating oil and the wax varies depending on the amount of the solid lubricant used, the type of sliding parts used, the lubricating conditions, etc., but is generally wax: lubricating oil and is in the range of 5:95 to 50:50. The range is appropriate.

As the solid lubricant used in the lubricant composition of the present invention, various types such as boron nitride, molybdenum disulfide, graphite, fluorine-based polymer and fluorine-containing copolymer can be used. Among these, fluorine-based polymer powders such as polytetrafluoroethylene (PTFE) and fluorine-containing copolymer powders, which are also used in conventional products, are suitable because low friction is required. Specific examples include PTFE fine powder and polyvinylidene fluoride fine powder. These can be used alone or in combination of two or more. In the present invention, PTFE is most preferably used. Moreover, 0.1-10 micrometers is suitable for the average particle diameter of the solid lubricant to be used.
The amount of solid lubricant added to the lubricant composition is determined by the lubrication location to be applied. On the other hand, in the present invention, wax is added to prevent or reduce sedimentation of the solid lubricant. For this purpose, the weighted average specific gravity of the solid component (mixture of solid lubricant and wax) in the lubricant composition may be brought close to the weighted average specific gravity of the liquid components (solvent, lubricant and surfactant). Desirably, for example, the specific gravity difference is preferably within ± 10%.
The content of the solid lubricant in the lubricant composition is generally suitably from 0.1 to 20% by weight, preferably from 0.2 to 10.0% by weight, more preferably from 0.5 to 5.0% by weight. preferable.

The surfactant used in the lubricant composition of the present invention is an anionic surfactant. For example, carboxylate, sulfonate, sulfate ester salt, phosphate ester salt and the like can be mentioned. Examples of carboxylates include soaps (for example, potassium oleate and castor oil potassium), N-acyl amino acid salts, polyoxyethylene alkyl ether carboxylates, acylated peptides, and the like. For example, sodium dodecane sulfonate), hydroxyalkyl sulfonate (eg sodium hydroxyalkane (C8-C24) sulfonate), alkyl benzene sulfonate (eg sodium dodecyl benzene sulfonate), alkyl naphthalene sulfonate, naphthalene sulfone Acid salt-formalin condensate (eg, sodium salt of β-naphthalenesulfonate-formalin condensate), sulfosuccinate (eg, sodium dioctylsulfosuccinate), α-olefin sulfonate, N -Acyl sulfonate and the like as sulfate ester salts include sulfated oil, alkyl sulfate, alkyl ether sulfate, polyoxyethylene alkylallyl ether sulfate, alkylamide sulfate and the like, Examples thereof include alkyl phosphates, polyoxyethylene alkyl ether phosphates, and polyoxyethylene alkyl allyl ether phosphates.
In general, the content of the anionic surfactant in the lubricant composition is suitably 0.5 to 15.0% by mass, preferably 1.0 to 10.0% by mass, and 2.0 to 7.0. The mass% is more preferable.

  In the lubricant composition of the present invention, the sum of the components other than the aqueous solvent that contribute to substantial lubrication, that is, the non-volatile component, the lubricating oil, wax, solid lubricant, and anionic surfactant is preferably 1. It is 0.0-50.0 mass%, More preferably, it is 3.0-40.0 mass%, Most preferably, it is 5.0-30.0 mass%. This range is preferable because a sufficient film can be formed and an appropriate solution viscosity can be obtained.

The aqueous solvent used in the lubricant composition of the present invention may be water alone or a mixture of water and a water-soluble organic solvent. From the viewpoint of workability, economy, and environmental load, the ratio of the water-soluble organic solvent in the solvent consisting of water and the water-soluble organic solvent is preferably 0 to 50 parts by mass with respect to 100 parts by mass of water. Preferably it is 1-20 mass parts, Most preferably, it is 2-10 mass parts.
Examples of the water-soluble organic solvent include alcohols (for example, methanol, ethanol, propanol, butanol, isopropanol, isobutanol), glycols (for example, ethylene glycol, diethylene glycol, cellosolve, methyl cellosolve, butyl cellosolve) and the like. Particularly preferred are ethanol, propanol, isopropanol and the like.
By including a water-soluble organic solvent, performance such as drying and wettability can be imparted.
In general, the content of the solvent in the lubricant composition is suitably from 50.0 to 99.0 mass%, preferably from 60.0 to 97.0 mass%, more preferably from 70.0 to 95.0 mass%. preferable.
In the lubricant composition of the present invention, various additives such as an antioxidant, an extreme pressure agent, and a rust preventive agent that are usually used in a lubricant can be appropriately added. The content of these additives is usually 0.01 to 5.0% by mass.

The lubricant composition of the present invention can be produced by a usual method. For example, a method of kneading a lubricating oil, a wax and a solid lubricant and then dispersing the kneaded product with an anionic surfactant in a solvent can be mentioned.
The method specifically includes the following steps.
(A) A predetermined amount of lubricating oil, wax, and solid lubricant are mixed, heated to a temperature about 5 to 15 ° C. higher than the melting point of the wax, and then allowed to cool. (B) After cooling, kneading is performed using a kneader, for example, a three-stage roll mill, a colloid mill, or the like until uniform. (C) An anionic surfactant is added to the kneaded product obtained above and mixed sufficiently, and then dispersed in a predetermined amount of solvent. (D) Take this in a container and seal it.
As another method, the lubricating oil, wax, solid lubricant, anionic surfactant and solvent can be dispersed together using a ball mill or the like.
The amount of each component used in these methods is as described above.

The lubricant composition of the present invention forms a lubricating film containing lubricating oil, wax, solid lubricant and anionic surfactant in the application member after volatilizing the solvent.
The member to which the lubricant composition of the present invention is applied is not particularly limited as long as lubrication is required. For example, the present invention is applied to places where lubrication / silence is required such as sliding parts, gears, bearings, and electrical contacts of precision equipment. The lubricant composition of the present invention is particularly preferably applied to resin parts such as audio / video equipments and information equipments, sliding parts between resin parts and metal parts, or metal parts, especially sliding parts between resin parts. It is particularly preferred to apply to. Examples of such resins include polyethylene, polypropylene, polyvinyl chloride, polystyrene, acrylonitrile butadiene styrene (ABS) resin, AS resin, methacrylic resin, polyvinyl alcohol, polyvinylidene chloride, polyethylene terephthalate, polyamide, polyacetal (POM), Polycarbonate (PC), modified polyphenylene ether, polybutylene terephthalate, GF reinforced polyethylene terephthalate, ultrahigh molecular weight polyethylene, polysulfone, polyethersulfone, polyphenylene sulfide, polyarylate, polyamideimide, polyetherimide, polyetheretherketone, polyimide, Liquid crystalline polyester, polytetrafluoroethylene, polyaminobismaleimide, polybisamide Azole, ABS / PC polymer alloy, etc., and particularly preferred are ABS, PC, POM, ABS / PC polymer alloy or the like.

The present invention is further directed to a sliding member having a lubricious coating.
The lubricant composition of the present invention can be applied to a sliding member or the like using a brush or brush, by spraying, or by dip coating in the lubricant composition. The applied amount is preferably 0.5 to 300 μm, more preferably 10 to 200 μm, as the thickness of the dry film after the solvent is volatilized.

  Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples.

Examples 1-5 and Comparative Examples 1-4
Various lubricant compositions were produced according to the composition (unit: mass%) described in Table 1 below.
Production Method A predetermined amount of lubricating oil, wax and solid lubricant were mixed, heated to a temperature 10 ° C. higher than the melting point of the wax, and then allowed to cool. After cooling, two passes were made with a three-stage roll mill. A surfactant was added to the obtained kneaded material, mixed well, and then dispersed in a predetermined amount of solvent. This was taken in a container and sealed.

Various physical properties of the lubricant composition produced as described above were evaluated by the following evaluation methods.
Resin resistance 1/4 quarter elliptical critical strain measurement method (issued by Lubricating Communications Co., Ltd., “Lubrication Economy”, No. 411, June 2000, right column on page 14, Fig. 2 Method of measuring strain at crack generation point) However, in the jig shown in FIG. 2, a = 127 mm, b = 38.1 mm, t = 2.0 mm, and a crack occurrence location (X value) of 112 mm or more was accepted and less than 112 mm was rejected. .
○: No crack occurred or X value is 112 mm or more X: X value is less than 112 mm Lubricity Tester: Tribogear HEIDON 14DR (manufactured by Shinto Kagaku)
Test piece: 3 / 8φ ABS sphere / ABS plate Load: 200 g Sliding speed: 600 mm / min
Sliding width: 10 mm Sliding frequency: 50 times Evaluation: Friction coefficient (μ)
○: Less than 0.05 Δ: 0.05 to less than 0.10 ×: 0.10 or more

Redispersibility test About 15 ml of a sample was placed in a test tube with a lid having a capacity of 18 ml, allowed to stand for 24 hours, shaken, and the state of redispersion of the precipitated solid was visually observed.
○: Dispersed easily Δ: Slightly difficult to disperse ×: Dispersibility difficult to disperse The wettability when applied to a PC plate using a clean stick and the coating state after drying were visually evaluated.
○: Good △: Slight repellency ×: Poor drying time Time to dry when applied to PC board ○: Less than 5 minutes ×: 5 minutes or more

上記表の特性評価欄中の「-」は、評価しなかったことを意味する。

“-” In the property evaluation column of the above table means that evaluation was not performed.

The various components used in the above Examples and Comparative Examples are as follows.
PTFE: Polytetrafluoroethylene
PAO: Polyalphaolefin
COE: Dialkyl carbonate wax: Montanic acid partially saponified ester wax surfactant 1: Sodium alkylbenzene sulfonate surfactant 2: Sodium sulfosuccinate surfactant 3: Polyoxyethylene alkyl ether surfactant 4: Hardened castor oil ethylene oxide addition Antirust agent: Alkenyl succinic acid antirust agent

From the results shown in Table 1 above, the lubricant compositions of Examples 1 to 5 of the present invention contain an anionic surfactant, so that they do not adversely affect various resins and have a low coefficient of friction. In addition, it can be seen that providing a lubricating film having a long life, that is, excellent resin resistance, lubricity, redispersibility, coating property, and drying property.
On the other hand, the lubricant compositions of Comparative Examples 1 to 4 containing a nonionic surfactant have poor resin resistance, particularly resistance to PC.

Claims (10)

A lubricant composition for forming a lubricating film , comprising at least one anionic surfactant selected from the group consisting of a lubricating oil, a wax, a solid lubricant, an alkylbenzene sulfonate, and a sulfosuccinate , and an aqueous solvent.   The lubricant composition according to claim 1, wherein the total amount of the lubricating oil, wax, solid lubricant and anionic surfactant is 1.0 to 50.0% by mass, and the balance is an aqueous solvent.   The lubricant composition according to claim 1 or 2, wherein the lubricating oil is at least one selected from the group consisting of polyalphaolefin oil, fatty acid ester oil, carbonate ester oil, alkyldiphenyl ether oil, alkylbenzene oil, and silicone oil.   The lubricant composition according to any one of claims 1 to 3, wherein the wax is at least one selected from the group consisting of montan wax and derivatives thereof, petroleum wax and polyethylene wax.   The lubricant composition according to any one of claims 1 to 4, wherein the solid lubricant is at least one selected from the group consisting of a fluorine-based polymer powder and a fluorine-containing copolymer powder.   The lubricant composition according to claim 5, wherein the solid lubricant is a polytetrafluoroethylene powder.   The lubricant composition according to any one of claims 1 to 6, wherein the aqueous solvent is water or a mixture of 50% by mass or more water and 50% by mass or less water-soluble organic solvent. The lubricant composition according to any one of claims 1 to 7, wherein the composition is a lubricant composition for forming a water-washable lubricating film .   A lubricious coating film formed from the lubricant composition according to claim 1.   A sliding member having the lubricating coating according to claim 9.