JP5738737B2 - Aqueous lubricant composition - Google Patents

Description

The present invention provides a water-based lubricating liquid composition having low COD and high wear resistance without using mineral oil, synthetic oil, glycols, and high molecular organic compounds by using a specific linear alkylbenzene sulfonate. It is about.

In recent years, with the deterioration of the global environment, interest in the environment has increased. In various devices, lubricating oil based on mineral oil and synthetic oil is used. However, since it contributes to water pollution, it is necessary to prevent leakage from the machine. For this reason, in the unlikely event of leakage from equipment, attempts have been made to study a lubricating liquid using water that has little environmental impact instead of base oil (Patent Documents 1 and 2). However, the durability of the wear resistance is not sufficient, and further improvement is required.

By the way, in the hydraulic oil in which flame retardancy is required, a hydraulic oil in which the base oil is changed to water having excellent flame retardance is already known instead of a lubricating oil based on mineral oil or synthetic oil. For example, a water-containing lubricating oil composition having a polyalkylene glycol diether compound having a specific structure, a polyoxyalkylene glycol monoether compound having a specific structure, a polyoxypropylene glycol monoether compound having a specific structure, and a fatty acid salt having a specific structure (Patent Documents) 3), a hydrous hydraulic fluid containing a polyoxyalkylene glycol ether compound having a specific structure (see Patent Document 4), and the like.

However, these inventions contain a certain amount of mineral oil, synthetic oil, glycols, high molecular organic compounds, etc. in order to maintain lubricity, so that the COD is high. For this reason, the hydraulic fluid leaked from the equipment is considered for treatment at a normal wastewater treatment facility, and consideration is given to improving the wastewater treatment performance, but the environmental load when lubricating oil leaks directly from the equipment into the river Until is not considered. Therefore, there is a need for a low COD lubricating liquid that has little impact on the environment. Generally, in order to reduce COD, the use of a lubricant such as mineral oil, synthetic oil, glycols, and high molecular organic compounds is used. Therefore, it is extremely difficult to ensure wear resistance.

On the other hand, a sliding part of a device that employs a water lubrication mechanism for environmental reasons has a polytetrafluoroethylene resin (hereinafter sometimes referred to as “PTFE resin” or “PTFE”) or a polyether ether ketone resin (hereinafter referred to as “PTFE resin”). Hereinafter, a resin having a self-lubricating action such as “PEEK resin” or “PEEK” may be used. However, since these resins have a mechanism that exhibits low friction by peeling (wearing) the surface layer as small pieces during friction, a large amount of peeled pieces accumulate on the sliding surface if peeling proceeds too much. In some cases, the frictional force increases. In particular, since this peeling easily proceeds on a sliding surface made of a resin and a metal, an aqueous lubricant used for the sliding surface using these resins is required to suppress the abrasion of the resin.

JP 2010-202788 A JP 2010-202789 A Japanese Patent Laid-Open No. 6-279979 Japanese Patent Laid-Open No. 10-183163

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a water-based lubricant having low COD and high wear resistance, and further, a sliding portion between a resin and a metal. and to provide a water-based lubricant that can improve the sustainability of anti-wear properties to.

As a result of diligent research to solve the above problems, the present inventor blended mineral oil, synthetic oil, glycol, polymer organic compound, and the like by blending a specific linear alkylbenzene sulfonate with water. without, it is possible to obtain the persistence of high anti-wear properties, further resin - found that it is possible to obtain a sustained high anti-wear properties Te sliding portion smell between the metal still and can achieve low COD The present invention has been completed based on this finding.

That is, the present invention provides an aqueous lubricant containing 0.01 to 0.25% by weight of a linear alkylbenzene sulfonate having a linear alkyl group having 6 to 18 carbon atoms in water and having a COD of 160 mg / L or less. It is a composition, and provides a water-based lubricating liquid composition characterized by being used for a sliding portion of a resin and a metal .
The present invention, in the aqueous lubricant composition, wherein the linear alkylbenzenesulfonate is to provide a water-based lubricant composition is a linear alkyl benzene sulfonic acid alkali metal salts and alkaline earth metal salts.

The water-based lubricating liquid composition of the present invention has a high wear resistance and low COD, and can be suitably used for various devices in which leakage prevention measures are saved. Further, it is possible to use the device with a sliding portion of the resin and metal.

The aqueous lubricant composition of the present invention contains a linear alkylbenzene sulfonate.
The alkyl group of the linear alkylbenzene sulfonate has 6 to 18 carbon atoms, preferably 8 to 16 carbon atoms, and particularly preferably 10 to 14 carbon atoms. When the alkyl chain length is less than 6, the effect of preventing wear cannot be obtained, and when it exceeds 18, the solubility in water is significantly lowered. Further, if the alkyl group is a branched chain, the durability of the antiwear property is lowered, and therefore the alkyl group needs to be a straight chain in the present invention. The reason why the durability of wear resistance is inferior when it is a branched chain is that the adsorption film having a high density of alkylbenzene sulfonate cannot be formed if it is branched at the sliding portion, and the durability of the wear prevention is It is thought that it falls.

The linear alkylbenzene sulfonate is not particularly limited as long as it is an alkali metal salt, but an alkali metal salt is preferable from the viewpoint of solubility in water, and a potassium salt and a sodium salt are particularly preferable.
The content ratio of the linear alkylbenzene sulfonate is 0.01 to 0.25% by mass, preferably 0.1 to 0.24% by mass, particularly preferably 0, based on the total amount of the aqueous lubricant composition. .15 to 0.23 mass%. If it is less than 0.01%, the durability of the wear prevention property cannot be obtained, and if it exceeds 0.25% by mass, the COD exceeds 160 mg / L.

The water content in the aqueous lubricating liquid composition of the present invention is 99.75 to 99.99% by mass, preferably 99.76 to 99.9% by mass, based on the total amount of the aqueous lubricating liquid composition. Particularly preferred is 99.77-99.8% by mass.
The water-based lubricating liquid composition of the present invention has a COD measured by the JIS K0102 drainage test method of 160 mg / L or less, preferably 150 mg / L or less. The lower the COD, the lower the environmental load, which is preferable. However, as described above, the aqueous lubricant composition of the present invention contains 0.01% by mass of the linear alkylbenzene sulfonate at the minimum, so the lower limit of the COD is 7 mg. / L or so.

The water-based lubricating liquid composition of the present invention basically does not contain mineral oil, synthetic oil, glycols, and high molecular organic compounds, or even if it is contained, the COD of the whole composition does not exceed 160 mg / L Therefore, the amount is small, and when considering the balance with other components, for example, it is preferably 10 mg / L or less.
Examples of the mineral oil include those obtained by purifying a lubricating oil fraction of crude oil by appropriately combining purification methods such as solvent refining, hydrorefining, hydrocracking refining, hydrodewaxing, and the like.

Synthetic oils, for example, those produced by using Fischer-Tropsch synthesis as a raw material for natural gas such as methane, phosphate ester, alkylbenzene, alkylnaphthalene, monoester, polyol ester, dibasic Examples include acid esters, silicate esters, chlorofluorocarbons, perfluoroalkyl ethers, polyphenyl ethers, and synthetic naphthenes.

Glycols include glycols such as ethylene glycol, diethylene glycol, trimethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, diethylene glycol, pentyl glycol, dipentyl glycol, hexylene glycol, and dihexylene glycol. And monoalkyl ethers of these glycols.

Examples of the high molecular organic compound include poly alpha olefin, polyisobutylene, polymethacrylate, polyalkyl styrene, ethylene propylene copolymer, styrene-butadiene hydrogenated copolymer, styrene-maleic anhydride ester copolymer, polyalkylene glycol, Examples include polyalkylene oxide, polyalkyleneimine, polyphenyl ether, polyacrylic acid, polyurethane, polyvinyl chloride, and polysaccharides.

In the aqueous lubricating liquid composition of the present invention, other than the linear alkylbenzene sulfonate other than mineral oil, synthetic oil, glycols, and high-molecular organic compounds, other components within a range where COD does not exceed 160 mg / L Can be appropriately blended. Examples of other additives include components used in ordinary aqueous lubricants, lubricants, metal deactivators, liquid phase or gas phase rust preventives, antifoaming agents, colorants, and other optional additives. Can be mentioned.

Examples of the lubricant include saturated fatty acids such as myristic acid, palmitic acid, lauric acid and stearic acid, unsaturated fatty acids such as oleic acid, linoleic acid and linolenic acid, aromatic fatty acids and dimer acids. These fatty acids may be used alone or in combination of two or more.
Metal deactivators include benzotriazole, tolyltriazole, 5
-Benzotriazole compounds such as methylbenzotriazole, carboxybenzotriazole and alkali metal salts or amine salts thereof, mercaptobenzothiazole and alkali metal salts thereof, and the like. These metal deactivators may be used alone or in combination of two or more.

Liquid phase or gas phase rust preventives include alkylmorpholines such as methylmorpholine and ethylmorpholine, triethanolamine, N
-It is possible to contain organic amines such as methyldiethanolamine, carboxylic acid alkali metal salts, and the like. These liquid phase or gas phase rust preventives may be used alone or in combination.
You may mix and use seeds or more.
Examples of the antifoaming agent include emulsions of silicone compounds, and examples of the coloring agent include alcohol-based coloring agents and metal-based coloring agents.

The water-based lubricating liquid composition of the present invention can be used in various applications that require a low environmental load. For example, in industrial machinery, transport machinery, particularly preferably equipment factories, industrial machinery bearings and gears, conveyor belt conveyors, machine tools, agricultural machinery, metal processing, rolling mills, power plant turbines, hydraulic equipment, compressors, etc. Can be used.

Further, the aqueous lubricant composition of the present invention can be used for sliding parts using various materials, for example, sliding parts between metal and metal and sliding parts between resin and metal. Although it can be applied, it can be preferably applied to the sliding portion between the resin and the metal from the viewpoint of the durability of the wear prevention property, and can be particularly suitably used for the sliding portion between the PTFE resin or the PEEK resin and the metal.
As the resin, in addition to PTFE resin and PEEK resin, polyimide resin, polyamideimide resin, polyethersulfone resin, polybutylene terephthalate resin, polycarbonate resin, polyamide resin, polyacetal resin, polyphenylene sulfide resin, nitrile-butadiene resin, A polyvinyl chloride resin etc. are mentioned. Examples of the metal include carbon steel, stainless steel, iron-containing alloy, cast iron, aluminum, aluminum alloy, nickel, nickel alloy, magnesium, magnesium alloy, copper, copper alloy, titanium, and titanium alloy.

Next, the present invention will be described more specifically with reference to examples and comparative examples. In addition, this invention is not restrict | limited at all by these examples.
(Examples 1-3 and Comparative Examples 1-5)
As Examples 1-3 and Comparative Examples 1-5, the aqueous | water-based lubricating fluid composition of Table 1 was prepared using the following alkylbenzenesulfonic acid. Each aqueous lubricant composition was measured for the sustainability of pH, COD, and anti-wear properties by the following evaluation methods. The evaluation results are shown in Table 1.

Linear alkylbenzene sulfonate:
(A) Linear alkylbenzenesulfonic acid sodium salt having 10 to 14 carbon atoms in the alkyl group (B) n-butylbenzenesulfonic acid sodium salt having 4 carbon atoms in the alkyl group (C) The alkyl group having 8 carbon atoms 2-ethylhexylbenzenesulfonic acid sodium salt

<Evaluation method>
(1) COD measurement COD was measured by the JIS K0102 drainage test method.
(2) Wear prevention test (sustainability of wear prevention)
Using the LFW-1 tester defined in ASTM D 2714, the test was conducted under the conditions of a rotation speed of 2000 rpm, a liquid temperature of 40 ° C., and a load of 5 pounds, and the wear depth of the blocks of the following materials was measured.
(A) PTFE resin-steel A block made of PTFE resin and a steel ring conforming to ASTM D 2714 were used, and the test was conducted for 10 hours.
(B) PEEK resin—steel A block made of PEEK resin and a steel ring according to ASTM D 2714 were used, and the test was conducted for 10 hours.
(C) Steel-Steel A steel block and a steel ring according to ASTM D 2714 were used, and the test was conducted for 10 hours.

From the results shown in Table 1, it can be seen that the aqueous lubricant compositions of Examples 1 and 2 are excellent in wear resistance and have low COD.
On the other hand, Comparative Example 5 which does not contain a linear alkylbenzene sulfonate, Comparative Example 1 which is less than the blending amount defined in the present invention, and the number of carbon atoms defined in the present invention by the alkyl group of the blended linear alkylbenzene sulfonate It can be seen that Comparative Example 3, which is smaller than that, does not provide sufficient wear prevention durability.

Further, when the blending amount of the linear alkylbenzene sulfonate exceeds the blending amount specified in the present invention, the durability of wear prevention is good, but the COD becomes high, and the influence on drainage is a concern. It became.
Further, sufficient wear even when an alkylbenzene sulfonate having a branched alkyl group having 8 carbon atoms is blended in place of the linear alkylbenzene sulfonic acid having a linear alkyl group having 6 to 18 carbon atoms, which is a component of the present invention. It can be seen that the persistence of the preventive property cannot be obtained.

The water-based lubricating liquid composition of the present invention can be used in various applications that require a low environmental load. For example, in industrial machinery, transport machinery, particularly preferably equipment factories, industrial machinery bearings and gears, conveyor belt conveyors, machine tools, agricultural machinery, metal processing, rolling mills, power plant turbines, hydraulic equipment, compressors, etc. Can be used.

Claims (2)

Water, is blended is from 0.01 to 0.25% by weight of linear alkyl benzene sulfonate having a linear alkyl group having 6 to 18 carbon atoms, there by COD is an aqueous lubricant composition is not more than 160 mg / L And an aqueous lubricant composition for use in sliding portions of resin and metal . The aqueous lubricant composition according to claim 1, wherein the linear alkylbenzene sulfonate is an alkali metal salt of a linear alkylbenzene sulfonic acid.