JPS63309591A - Grease composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which has high long-term stability, has no adverse effect on a rubber member, and imparts excellent lubricity and rustproofness to metal, by mixing a specified polyoxyalkylene or ether derivative thereof, a metallic salt of a fatty acid, and a specified succinic acid compound. CONSTITUTION:A grease composition comprising 100pts.wt. lubricating base oil (A) comprising a polyoxyalkylene and/or ether derivative thereof (e.g., polyoxypropylene or polyoxypropylene monobutyl ether) having a kinematic viscosity (40 deg.C) of 10-1,500cSt; 5-20pts.wt. thickening component (B) comprising a metallic salt of a fatty acid (e.g., lithium 12-hydroxystearate); and 1-30pts.wt. rustproofing component (C) comprising a succinic acid compound selected from a alkenylsuccinic acid, an alkenylsuccinic anhydride, and an alkenylsuccinic ester [e.g., an alkenylsuccinic acid of the formula (wherein R is 8-20C alkenyl)]. This composition can be applied to a rubber member with no adverse effect thereon. It imparts excellent lubricity and rustproofness to metal and has high long-term stability. Therefore, it is useful as a grease for rubber in particular.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to grease compositions.

[Conventional technology]

It is necessary to apply a lubricant to sliding parts in the moving parts of industrial machinery and other equipment, and grease is generally used as a lubricant especially in parts where it is difficult to lubricate.

Therefore, it is necessary to suppress deterioration of the rubber as much as possible in sliding parts made of rubber or sliding parts where rubber parts may come into contact. Castor oil based greases are commonly used.

However, this castor oil-based grease has low stability over time and may soften or become oxidized and solidify in a short period of time.

Against this background, polyalkylene glycol-based greases have been proposed. However, this polyalkylene glycol-based grease has poor lubricity and rust prevention properties for metal materials, particularly iron, and has a very narrow range of application. In addition, greases designed to improve these points are disclosed in Japanese Patent Publications No. 13518/1980, No. 13519/1982, 9351/1981, and 130/1982.
It has been proposed in Publication No. 67, etc., but these are
In both cases, the rust prevention properties are still unsatisfactory.

[Purpose of the invention]

An object of the present invention is to provide a grease composition which has the above-mentioned problems but has little adverse effect on rubber and has excellent rust prevention properties against metal materials.

[Means to solve problems]

The grease composition of the present invention is characterized by comprising the following components A to C.

Component A: Kinematic viscosity at a hot water temperature of 0°C is 10 to 1500c
st.

polyoxyalkylene and/or its ether derivative 100 parts by weight Component B: fatty acid metal salt
5 to 20 parts by weight Component C: at least one succinic acid compound selected from the group consisting of alkenyl succinic acid, alkenyl succinic anhydride, and alkenyl succinic ester 1 to 30 parts by weight Component A in the grease composition of the present invention is a component as a lubricating base oil consisting of polyoxyalkylene or its ether derivative, and is itself known as described in the above-mentioned patent publication. In the present invention, as this component A, polyoxyalkylene (both terminal groups are hydroxyl groups (OH)
Polyoxyalkylene monoalkyl ether (also called "polyoxyalkylene monool" because one of the terminal hydroxyl groups is etherified), polyoxyalkylene dialkyl ether, glycerin (Polyoxyalkylene)ether (triether is also called "polyoxyalkylene triol" because it has three terminal hydroxyl groups) and mixtures thereof can be used.

Specific examples of the above polyoxyalkylene include polyoxyethylene, poly(oxypropyleneoxyethylene), poly(oxybutyleneoxyethylene), and polyoxyalkylene.
(oxypentylene oxyethylene), polyoxypropylene, poly (oxypentylene oxypropylene)
etc. can be mentioned.

Specific examples of polyoxyalkylene alkyl ether include polyoxypropylene monobutyl ether, polyoxypropylene monopropyl ether, polyoxybutylene monobutyl ether, polyoxyethylene oxypropylene monobutyl ether, polyoxyethylene oxypropylene monobutyl ether, and polyoxypropylene monobutyl ether. Examples include ethylene oxypropylene monobentyl ether.

Specific examples of glycerin (polyoxyalkylene) ether include glycerin tri (polyoxyethylene) ether, glycerin tri (polyoxypropylene) ether, and glycerin tri [poly(oxyethylene oxypropylene)] ale.

Among the above, it is particularly preferable to use polyoxypropylene monobutyl ether in the present invention.

Component B is a thickener component in grease and is known per se. As component B, various fatty acid metal salts can be used in the present invention, and specific examples include 12-oxystearic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, and linoleic acid. Metal salts of f1 acid such as calcium salts, lithium salts, aluminum salts, barium salts, etc. can be mentioned, but it is particularly preferable to use lithium 12-oxystearate, depending on the proportion of this component B. Since the consistency of the resulting grease composition varies, the proportion of component B used is adjusted depending on the required consistency.

The succinic acid compound of component C is commercially available as a rust preventive additive for hydraulic oil and the like. For example, there are alkenylsuccinic acid represented by the formula % formula % (wherein R represents an alkenyl group having 8 to 20 carbon atoms), its anhydride, or its alcohol ester with a monohydric or polyhydric alcohol.

The proportion of component C is 1 to 30 parts by weight based on the total of 100 parts by weight of components A and B;
If it is less than 30 parts by weight, the desired excellent rust prevention properties cannot be obtained from the resulting grease composition, and if it exceeds 30 parts by weight,
The resulting grease composition becomes fluid and cannot be used as a grease.

In the present invention, in addition to the above components A to C,
Additional components can be blended, examples of which include antioxidants, solid lubricants, and others.

Examples of antioxidants include 1,1.3-)lis(2-methyl-4-hydroxy-5-t-butylphenyl)butane, 4.4°-butylidenebis(3-methyl-5-1-butylphenol), n-octadecyl-3-(4°-hydroxy-3°,5°-di-t-butylphenyl)propionate, 3.5-di-t-butyl-4-hydroxytoluene, 2.6-di-t-butylphenol , and other phenolic antioxidants can be used. These antioxidants are preferably used in a proportion of 0.1 to 15 parts by weight based on a total of 100 parts by weight of components A and B.

As the solid lubricant, polytetrafluoroethylene, melamine cyanurate adducts, and others can be used, and molybdenum disulfide, tungsten disulfide, boron nitride, graphite fluoride, and others can also be used in combination.

The grease composition of the present invention can be produced by a conventional method, and component C and optional additives may be added to a mixture of component A and component B and heated. .

[Effects] As described above, the grease composition according to the present invention comprises component A consisting of a specific polyoxyalkylene or its ether derivative as a lubricating base oil, and component B consisting of a fatty acid metal salt as a thickener. Furthermore, since it contains component C as a rust preventive agent made of a specific succinic acid compound, as will be clear from the explanation of the examples described later, it also has the same effect when applied to rubber members. It has no adverse effect on rubber parts, has excellent lubricity and rust prevention for metal materials, and has high stability over time (especially useful as a rubber grease). .

(Examples) Examples of the present invention will be described below, but the present invention is not limited thereto.

Examples 1 to 3 and Comparative Examples 1 to 5 100 parts by weight of polyoxypropylene glycol monobutyl ether having a kinematic viscosity of 60 cst at 40°C;
Lithium 12-hydroxystearate ("lithium soap") shown in Table 1 as a thickener was charged into a production kettle, and the temperature was raised to 195° C. while stirring. This is heated to 100℃
The mixture was cooled to room temperature, then the rust preventives and antioxidants listed in Table 1 were added thereto, thoroughly stirred and mixed, cooled to room temperature, and homogeneously kneaded using a roll mill to obtain various grease compositions.

Comparative Example 6 100 parts by weight of the same polyoxypropylene glycol monobutyl ether as in the above example and organic hentonite (
Benton J) 15.9 parts by weight and 2 parts of propylene carbonate
．． 3 parts by weight and a rust preventive agent were mixed at room temperature and milled uniformly using a roll mill to obtain a grease composition.

The grease compositions obtained in Examples 1 to 3 and Comparative Examples 1 to 6 above were used as samples, and the following measurements and tests were performed on each of them. The results are shown in Table 2.

l) Determination of consistency The mixing consistency was determined in accordance with JIS K-2220.

2) Measurement of 1 oil degree Based on JIS K-2220, the oil separation degree was determined after 24 hours at 100°C.

3) Measuring the amount of evaporation Put 15 g of sample grease in a Petri dish with a diameter of 40 mm, leave it uncovered in a constant temperature bath at 120°C, and after 100 hours, take it out and weigh it to determine the amount of weight loss due to evaporation. Ta.

4) Rust prevention test The surface of cold-rolled steel plate r 5PCCJ is polished with No. 240 sandpaper, thoroughly washed with a solvent, and then a very thin layer of sample grease is applied and spread, and the sample grease is prevented from adhering to the gauze using gauze. Wipe to temperature 80℃
The time required for rust to occur after being left at a relative humidity of 95% was determined.

5) Lubricity test ■Using a high-speed 4-ball tester, the number of rotations was 120 Orpm, and the load was 4.
The average diameter of the wear scars produced during one hour of operation at 0 kg was measured.

Using a shell 4-ball tester, a heavy-duty machine was operated for 1 minute at a rotational speed of 1500 rpm, and the minimum load at which seizure occurred was determined.

6) Rubber test: natural rubber, acrylonitrile butadiene rubber (NB)
R), a test rubber piece made of chloroprene and ethylene propylene diene rubber (EPDM) was immersed in the sample grease at 80°C for 100 hours, and then JIS K-
6301 (vulcanized rubber testing method), changes in volume and changes in hardness were determined for each rubber piece.

From the results in Table 2, it can be seen that each of the grease compositions according to the examples of the present invention had sufficiently satisfactory properties in the lubricity and rubber immersion tests, and had very excellent rust prevention properties. It is clear that it has the following. On the other hand, although the grease composition of the comparative example has practical properties in lubricity and rubber immersion tests,
It has low rust resistance. Especially Comparative Example 4 and Comparative Example 5
is an example in which a rust preventive agent exemplified in the above-mentioned known patent publication is used, but the results are unsatisfactory, and there is a clear difference in rust preventive properties when compared with the present invention. Also, comparative example 6
From the results, when a thickener made of organic bentonite is used, sufficient results cannot be obtained even if the succinic acid compound of the present invention is used.

Claims (1)

[Claims] 1) Component A: Kinematic viscosity at a temperature of 40°C is 10 to 150
0cst. Component B: 5 to 20 parts by weight of a fatty acid metal salt; Component C: selected from the group consisting of alkenyl succinic acid, alkenyl succinic anhydride, and alkenyl succinic ester. 1 to 30 parts by weight of at least one succinic acid compound.