JPH0226665B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a brake grease composition.
More specifically, the present invention relates to a general-purpose brake grease composition that can be used in various locations. [Prior Art] In recent years, with the increasing performance and speed of automobiles, the braking performance of brakes is also required to have high performance, stability, and long-term durability. Conventionally, there is no universal brake grease, and several types of grease are used for one brake. In other words, brake rubber grease is applied to areas that come into contact with rubber parts and brake fluid, brake grease is applied to areas that do not come into contact with rubber parts and become hot, and brake grease is applied to areas that come into contact with rubber parts and become hot. Silicone grease is selectively used. Brake grease is generally a lubricating base oil whose main ingredients are refined mineral oil, olefin-based synthetic oil, etc., with thickening agents such as lithium soap, aluminum composite soap, organic bentonite, and polyurea. It is used.
In addition, as rubber grease for brakes, metal soaps such as lithium 12-hydroxystearate and linear fatty acid lithium are used as thickening agents to lubricating base oils mainly composed of polyoxypropylene glycol monoalkyl ether and castor oil. Those containing organic bentonite are used. However, if the location where they are used is incorrectly selected, the desired effect may not be obtained; for example, if brake rubber grease is used instead of brake grease, the lubricity will be poor. If brake grease is used instead of brake rubber grease, it will swell and deteriorate the rubber, and it will not be compatible with brake fluid, causing clogging. Furthermore, using silicone grease instead of rubber grease for brakes is not only uneconomical since silicone grease is expensive, but also has poor compatibility with brake fluid and poor anti-rust properties. In this way, it is necessary to use grease appropriately at predetermined locations on a single brake, and not only is it extremely complicated to use different greases, but also several types of grease must be kept on hand at all times for repairs. Moreover, if the wrong grease is used, the above-mentioned problems may occur, and there is a risk of a serious accident. In addition, as mentioned above, rubber grease for brakes contains metal soap such as linear fatty acid lithium as a thickening agent, so it has poor heat resistance and does not meet the required brake performance. . [Object of the Invention] An object of the present invention is to provide a general-purpose brake grease composition that satisfies almost all of the performances required of the three types of grease described above and does not require different uses depending on the location of use. [Structure of the Invention] The present invention is directed to the kinematic viscosity (at 100°C)
100 parts (parts by weight, same below) of polyoxypropylene glycol monoalkyl ether with 10 to 100 cSt
A lubricating base oil containing 5 to 40 parts by weight of neopentyl polyol ester having a kinematic viscosity of 5 to 70 cSt, and 5 to 30 parts of the general formula () to 100 parts of the lubricating base oil: (In the formula, R is an alkyl group having 10 to 30 carbon atoms, M is a lithium atom, a sodium atom, a potassium atom,
The present invention relates to a brake grease composition comprising a metal terephthalamate represented by a calcium atom or a barium atom (n is 1 or 2). [Embodiments of the Invention] The polyoxypropylene glycol monoalkyl ether, which is a component of the lubricating base oil in the grease composition of the present invention, has a kinematic viscosity of 10 to 100 cSt, preferably 20 to 85 cSt, particularly preferably 30 to 70 cSt. It is something. When the kinematic viscosity is less than 10 cSt, the amount of evaporation of the grease increases and the heat resistance deteriorates. On the other hand, when it exceeds 100 cSt, the viscosity at low temperatures becomes too high, reducing brake operability in low temperature regions and in winter. Examples of polyoxypropylene glycol monoalkyl ether include the general formula: (In the formula, R is a methyl group, an ethyl group, a propyl group,
Examples include those represented by an alkyl group having 1 to 6 carbon atoms, such as isopropyl group, butyl group, isobutyl group, pentyl group, and hexyl group (n is an integer of 5 to 300). Neopentyl polyol ester, another component of the lubricating base oil, has a kinematic viscosity of 5 to 70 cSt, preferably 10 to 60 cSt, particularly preferably 15 to 50 cSt. When the kinematic viscosity is less than 5cSt, it causes the rubber parts used in the brakes to swell, and when it exceeds 70cSt, the viscosity at low temperatures becomes too high, reducing brake operability in low-temperature regions and in winter. . Examples of neopentyl polyol ester include neopentyl glycol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, hexanoic acid, heptanoic acid, octanoic acid, isooctanoic acid, 2-ethylhexanoic acid, nonanoic acid, Isononanoic acid, decanoic acid, isodecanoic acid, caprylic acid, lauric acid, palmitic acid, stearic acid, aragic acid, behenic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid Examples include di-, tri-, or tetra-esters with, for example, NOF
Those commercially available from Co., Ltd. as the Unistar series can also be used. The amount of neopentyl polyol ester to polyoxypropylene glycol monoalkyl ether is 5 to 40 parts per 100 parts of polyoxyalkylene glycol monoalkyl ether,
Preferably it is 6 to 35 parts, particularly preferably 7 to 30 parts. If the amount of neopentyl polyol ester is less than 5 parts, the lubricating performance of the grease composition will deteriorate, and if it exceeds 40 parts, the rubber parts used in the brake will swell, reducing the operability of the brake. The grease composition of the present invention further contains a metal terephthalamate represented by the above general formula () as a thickening agent. The alkyl group represented by R in the general formula () has 10 to 30 carbon atoms, preferably 15 to 22 carbon atoms, such as decyl group, decenyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group, octadecenyl group,
Examples include eicosyl group and tocosyl group. Preferred metal terephthalamates include, for example, potassium N-octadecyl terephthalamate, sodium N-octadecyl terephthalamate, lithium N-octadecyl terephthalamate, calcium N-octadecyl terephthalamate, barium N-octadecyl terephthalamate, and potassium N-octadecyl terephthalamate. N-dodecyl terephthalamate, sodium N
-Tetradecyl terephthalamate, lithium N-
Tetradecyl terephthalamate, calcium N-
Examples include tetradecyl terephthalamate, barium N-tetradecyl terephthalamate, sodium N-hexadecyl terephthalamate, and sodium N-octadecenyl terephthalamate. The amount of metal terephthalamate is based on the lubricating base oil.
5 to 30 parts per 100 parts, preferably 6 to 25 parts,
Particularly preferably 7 to 20 parts. If it is less than 5 parts, the grease is too soft and will run off from the part where it is used, and is therefore unsuitable. If it exceeds 30 parts, the grease is too hard and increases the operating torque, which is unsuitable. In order to further improve its performance, the grease composition of the present invention may contain various additives, such as phenolic and amine antioxidants, metal sulfonate, amine, metal soap, and ester anticorrosive agents. Appropriate amounts of rust agents, anti-wear agents such as molybdenum disulfide, graphite, tungsten disulfide, and boron nitride may be added. The method for preparing the grease composition of the present invention is not particularly limited, and various methods may be employed. For example, methyl N-octadecyl terephthalamate and 2 to 3 times the amount of polyoxypropylene glycol monoalkyl ether, neopentyl polyol ester, or a mixture thereof are placed in a reaction vessel equipped with a stirrer, and while stirring together with methyl terephthalamate, Heat to approximately 130℃ to dissolve. Separately, a reaction equivalent amount of metal hydroxide with methyl terephthalamate is dissolved in water in an amount 3 to 5 times the amount of the metal hydroxide. This is placed in the reaction vessel and reacted to produce metal terephthalamate. After further dehydration with stirring, add the remaining polyoxypropylene glycol monoalkyl ether or neopentyl polyol ester or a mixture thereof, and heat the mixture to about 150°C.
After heating to 80-85°C, the mixture is cooled to approximately 80-85°C, and then antioxidants and anti-corrosion agents are added and mixed thoroughly. The grease composition of the present invention can be obtained by processing this product using a three-roll mill or homogenizer, adding an anti-wear agent such as molybdenum disulfide as necessary, and thoroughly stirring the mixture. If metal terephthalamate is used from the beginning, the metal terephthalamate and the entire amount of oil used may be mixed by stirring. The brake grease composition of the present invention has excellent heat resistance and low-temperature properties, does not have any adverse effects on rubber such as swelling the rubber, and has excellent lubricity, so it can be applied to all locations where grease is used in brakes. be able to. Applicable brakes include, but are not limited to, disc brakes and drum brakes for automobiles and construction machinery. Next, the grease composition of the present invention will be explained with reference to Examples, but the present invention is not limited to these Examples. Example 1 21 parts of methyl N-octadecyl terephthalamate was added to 25 parts of polyoxypropylene glycol monobutyl ether (kinematic viscosity 58.2 cSt) and dissolved at 130°C, followed by neopentyl polyol ester.
35 parts (23 parts of Unistar C3372A and 12 parts of Unistar C3373A from NOF Corporation, kinematic viscosity 23.4 cSt) were added. A solution prepared by dissolving 1.8 parts of lithium hydroxide in 5 parts of water was added to the resulting mixed solution, and the mixture was stirred and saponified. Then, after raising the temperature to 150℃, polyoxypropylene glycol monobutyl ether (kinematic viscosity
58.2 cSt) was added, and the mixture was further heated to 150°C and then cooled. To this mixture, 1 part of an antioxidant and 3 parts of a corrosion and rust preventive agent were added, milled, and thoroughly stirred to obtain a brake grease composition of the present invention. Example 2 21 parts of methyl N-octadecyl terephthalamate and 35 parts of neopentyl polyol ester (17.5 parts of Unistar C3372A and 17.5 parts of Unistar C3373A,
After melting at 120°C, 20 parts of polyoxypropylene glycol monobutyl ether (dynamic viscosity 45.8 cSt) was added. A solution of 1.8 parts of lithium hydroxide dissolved in 7 parts of water was added to the resulting mixed solution and stirred to saponify it. Then, after raising the temperature to 150℃, polyoxypropylene glycol monobutyl ether (kinematic viscosity 45.8cSt)
80 parts were added, further heated to 170°C, and then cooled. This stuff includes 1 part of antioxidant and 3 parts of anti-corrosion agent.
1 part and 2 parts of molybdenum disulfide were added and milled to obtain a brake grease composition of the present invention. Examples 3 to 8 Brake grease compositions of the present invention having the compositions shown in Table 1 were prepared in the same manner as in Example 1 or 2. Comparative Examples 1 to 4 As shown in Table 1, comparative brake grease compositions were prepared in the same manner as in Example 1, except that the blending amount and kinematic viscosity were outside the range of the present invention. Comparative Example 5 9.4 parts of 12-hydroxystearic acid was added to 30 parts of polyoxypropylene glycol monobutyl ether (kinetic viscosity 48.8 cSt) and dissolved by heating to 90°C, then 1.4 parts of lithium hydroxide was dissolved in 6 parts of water. The solution was added and saponified and dehydrated while heating and stirring. Then, it was heated to 160℃ and polyoxypropylene glycol monobutyl ether (kinematic viscosity 48.8cSt)
After adding 40 parts, the temperature was raised to 220°C, and the mixture was cooled to 90°C while adding 30 parts of polyoxypropylene glycol monobutyl ether (kinetic viscosity: 48.8 cSt). A comparative brake grease composition was obtained by adding 1.4 parts of an antioxidant and 3 parts of a corrosion and rust preventive agent to this mixture and milling it. Comparative Example 6 8.1 parts of 12-hydroxystearic acid was added to 30 parts of polydecene (kinematic viscosity 20.0 cSt) and dissolved by heating at 90°C. A solution of 1.2 parts of lithium hydroxide dissolved in 5 parts of water was added and stirred with heating. While saponifying and dehydrating. The mixture was then heated to 160°C, added to 70 parts of polydecene, and further heated to 220°C, then cooled in a quenching vat. 1 part of an antioxidant and 2.4 parts of a corrosion and rust preventive agent were added to this mixture and milled to obtain a brake grease composition for comparison. Comparative Example 7 70 parts of refined mineral oil (kinematic viscosity 32 cSt) was heated to 80°C,
After 10 parts of bentonite was added and stirred, 0.8 part of ethanol was added and milled. Next, add polydecene (kinematic viscosity 25 cSt), 1.2 parts of antioxidant,
A brake grease composition for comparison was obtained by adding 1.2 parts of a corrosion and rust preventive agent and milling. Comparative Example 8 Dimethyl silicone oil was multiplied with silica gel to obtain silicone grease.

【table】

[Table] The following properties were investigated for the grease compositions prepared in Examples 1 to 8 and Comparative Examples 1 to 8. The results are shown in Table 2. The properties investigated and their test methods are as follows. Stability: JIS K2220 5.3 Dropping point: JIS K2220 5.4 Evaporation: JIS K2220 5.6 (Method B, 99°C, 22 hours) Oxidation stability: JIS K2220 5.8 (99°C, 100 hours) Oil separation: JIS K2220 5.7 (100℃, 24 hours) Wettability: JIS K2220 5.17 Salt spray: JIS K2246 4.33 Rubber swelling test: JASO M307 70 (120℃, 70 hours) Lubricity: Tested on blocks using a Chimken tester according to JIS K2220 5.16 Grease 2.0
g was applied, a load of 10 Lbs was applied, and the time until baking was measured. Brake fluid compatibility: 10 g of the grease composition and 90 g of brake fluid were placed in a beaker, heated to 60° C., and stirred for 3 hours.

【table】

[Table] As is clear from Table 2, if the amount of neopentyl polyol ester is too large, the rubber will swell and its compatibility with brake fluid will deteriorate (Comparative Example 1), and if it is too small, the lubricity will be extremely poor. (Comparative Example 2) If the kinematic viscosity of polyoxypropylene glycol monobutyl ether is too small, the amount of evaporation will increase (Comparative Example 3), and if the kinematic viscosity of neopentyl polyol ester is too small, the rubber will swell and the degree of oil separation will increase (Comparative Example 4). Conventional brake rubber grease (Comparative Example 5) has a problem with lubricity, and conventional brake greases (Comparative Examples 6 and 7) both swell the rubber and have a high degree of oil separation, and also have poor lubricity and brake performance. There are also problems with compatibility with liquids. Silicone grease (Comparative Example 8) has poor salt water resistance and poor compatibility with brake fluid. On the other hand, as shown in Table 2, the grease composition of the present invention has all the characteristics required for various brake greases, and there is no need to differentiate between different uses depending on the location.

Claims (1)

[Claims] 1. Polyoxypropylene glycol monoalkyl ether having a kinematic viscosity of 10 to 100 cSt at 100°C.
Kinematic viscosity at 100℃ per 100 parts by weight is 5~
70cSt neopentyl polyol ester 5-40
A lubricating base oil in which parts by weight are blended, and the lubricating base oil
General formula () of 5 to 30 parts by weight per 100 parts by weight: (In the formula, R is an alkyl group having 10 to 30 carbon atoms, M is a lithium atom, a sodium atom, a potassium atom,
A brake grease composition comprising a metal terephthalamate represented by a calcium atom or a barium atom (n is 1 or 2).