JPH027356B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved lubricating grease composition that has good lubricity, particularly at high temperatures, withstands high loads, and has a long life. Grease-lubricated parts such as bearings and sliding surfaces of mechanical equipment are exposed to high temperatures and subjected to heavy loads.
Furthermore, in the case of bearings, lubrication is often performed under harsh conditions, including high-speed rotation conditions. The various greases currently on the market do not necessarily exhibit satisfactory properties under such harsh conditions. The present invention is a lubricating grease composition having a new composition that has been improved to exhibit particularly stable lubrication properties under such conditions, and has strong adhesion to metal surfaces during high-temperature lubrication, excellent shear stability, and extremely high shear stability. The object of the present invention is to provide a lubricating grease composition that has excellent pressure properties, can withstand high loads, and has a particularly long lubrication life. As a result of research, the present inventors have found that this purpose is for lubricating oils characterized by containing 5 to 40% by weight of calcium salts of dibasic acids and calcium salts of N-alkyl-substituted monoamic acids as increasing agents. It has been found that this can be achieved by a grease composition. The dibasic acid used in the present invention refers to an organic compound having a hydrocarbon group and two carboxyl groups bonded to it, preferably those having an aliphatic hydrocarbon group, and HOOC
(CH ₂ ) _o A dibasic acid represented by the molecular formula of COOH, n
is 4 to 18, which is most suitable for the purpose of the present invention. Examples include adipic acid, pimelic acid, superic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecane. There are diacids, nonadecanedioic acid, and eicosanedioic acid. The N-alkyl-substituted monoamic acid used in the present invention is a compound having the structure RNHOC(CH ₂ ) _o COOH, where R represents an alkyl group having 12 to 22 carbon atoms, and n is 4 to 18. This N-alkyl-substituted monoamic acid is easily synthesized from n-alkylamine and dibasic acid, but in the present invention, even if a pre-synthesized one is added to lubricating oil, n-primary alkylamine It is also possible to synthesize by adding dibasic acid and dibasic acid. n Primary alkylamine is one aliphatic straight chain alkyl group and one amino group.
The most suitable organic compound for the purpose of the present invention is an organic compound in which these groups are bonded, and among these, an alkyl group having 12 to 22 carbon atoms. For example, ndodecylamine, ntridecylamine, n
pentadecylamine, nhexadecylamine, n
heptadecylamine, noctadecylamine, n
Natural fat amines include docosylamine and mixtures thereof such as beef tallow amine and coconut oil amine. Here, dibasic acid is an organic compound having a hydrocarbon group and two carboxyl groups bonded to it, and among these, dibasic acid is represented by the molecular formula of HOOC(CH ₂ ) _o COOH, where n is 4 to 18 The one that meets the purpose is the most appropriate. Examples include adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid. acids, nonadecanedioic acid and eicosanedioic acid. If N-alkylamine and dibasic acid are reacted one molecule at a time, N-alkyl-substituted monoamic acid can be obtained, and there are various types such as N-dodecyladipamic acid and N-octadecylsebacamic acid. All of these are within the scope of this invention, as are mixtures thereof. In the present invention, dibasic acids and N-alkyl-substituted monoamic acids are used as calcium salts.
Similar performance can be obtained with barium salt and magnesium salt, but barium salt is toxic and its use is restricted in France, for example. Magnesium salts (also lithium salts and sodium salts) have poor load-bearing performance. The present invention is a lubricating grease composition in which a lubricating oil is used as a base oil and is enriched by co-containing two types of compounds: a calcium salt of a dibasic acid and a calcium salt of an N-alkyl-substituted monoamic acid. , the total amount of these two types of compounds is 5 to 5 to the entire composition.
The object of the present invention can be achieved within the range of 40% by weight, and this is the scope of the present invention. If the total amount of the above two types of compounds is less than 5%, adhesion and heat resistance will be poor, and if it is more than 40%, it will be difficult to form a grease-like appearance and the adhesion will be poor, and the object of the present invention cannot be achieved in both cases. Further, as shown in Table 1, a preferred range in which the molar ratio of the calcium salt of the N-alkyl-substituted monoamic acid to the calcium salt of the dibasic acid is 1:0.3 to 1:8 is confirmed to be effective. The lubricating oils used in the present invention are refined mineral oils and synthetic oils having lubricating viscosity. Synthetic oils include diester oils such as dioctyl sebacate (DOS), polyester oils such as pentaerythritol tetraester oil, and polyoxyethylene- Glycol ether oil such as polyoxypropylene block polymer, α-olefin polymerized oil such as polymerized oil with an average molecular weight of 300 to 1000 obtained by polymerizing monoolefin having 4 to 20 carbon atoms, silicone oil such as liquid polymethylsiloxane, m - Polyphenyl ether oils such as bis(m-phenoxy, phenoxy)benzene and the like are included. Various methods can be applied to the method for producing the lubricating grease composition of the present invention. An example is shown below. Production method A: Mix excess dibasic acid and n-alkylamine,
A mixture of the N-alkyl-substituted monoamic acid and the dibasic acid is prepared by heating and reacting, which is mixed with lubricating oil, and then a calcium salt is added and heated to saponify it to form a calcium salt of the dibasic acid and a calcium salt of the N-alkyl-substituted monoamic acid. is co-produced, cooled to room temperature and milled into a homogeneous grease. Manufacturing method B Calcium salts of dibasic acids and calcium salts of N-alkyl-substituted monoamic acids are added to lubricating oil, heated and stirred to dissolve and disperse, cooled to room temperature, and milled to obtain a uniform grease. Production method C Add N-alkyl-substituted monoamic acid to lubricating oil, heat to dissolve, then add calcium salt and heat to saponify, further heat and dehydrate, then add dibasic acid calcium salt and heat to dissolve and disperse. After that, it is cooled to room temperature and milled to obtain a uniform grease. In the above production method A, a mixture of an N-alkyl-substituted monoamic acid and a dibasic acid is mixed with lubricating oil, and the mixture is heated and saponified, but both of these substances have low melting points and are easily dissolved and dispersed in oil when heated. , therefore manufacturing is easy. Also, the cost of raw materials is relatively low. Although this point is favorable, the problem is that impurities are generated during the reaction, which adversely affects the properties of the product. It is caused by the reaction of excess dibasic acid and n-alkyl amine, and in addition to the target product of N-alkyl-substituted monoamic acid and dibasic acid, some N-alkyl-substituted monoamide is generated, which may have a negative effect on the lubricating life of the product grease. discovered. In this respect, production method B and production method C use pure N-alkyl-substituted monoamic acids or N-alkyl-substituted monoamic acid salts, so the cost of raw materials is higher than in A, but the influence of impurities can be avoided. However, in B and C, calcium dibasic acid is dispersed in oil, but this calcium dibasic acid is mainly a hard solid powder that is difficult to disperse even at high temperatures. Uniformly dispersing this is an important process for obtaining the high-performance grease of the present invention, so as a result of research, the present inventors have found that finely powdered grease is particularly suitable for
If a fine powder of 100 μm or less of calcium dibasic acid is mixed in advance with a portion of the base oil and milled using a roll mill, and this mixture is used in the manufacturing process, it will be easily dispersed in the composition and achieve the desired properties. It was confirmed that a lubricating grease composition of Therefore, in order to obtain a high-performance lubricating grease composition which is the object of the present invention, it can be said that the method of carrying out the above-mentioned dispersion treatment in the production method of B or C is preferable. but,
Since method A is also inexpensive, it is practical and appropriate when the objective is not to achieve very high performance. The grease of the present invention produced in this way has strong adhesion to metal surfaces, excellent shear stability, and excellent extreme pressure properties, and is suitable under high temperature, high load lubrication conditions, and when high speed conditions are added. As a result of experiments, we were able to confirm that stable lubrication and long lubrication life could be obtained. This excellent performance is believed to be due to the following reasons. One is that the composition of the present invention has oil separation properties suitable for grease lubrication. In other words, in grease lubrication, the grease separates due to heat in the lubricated part, and this separated oil provides lubrication, but with commonly used greases, the separated oil is rarely absorbed into the grease again. Therefore, the grease gradually loses its oil and the content of the thickening agent in the grease increases and hardens, leading to a decline in lubricating performance and the end of its life. However, in the lubricating grease composition of the present invention, the oil separated by this heat is absorbed into the grease again during the cooling process, so the content of thickening agent in the grease does not increase and the lubricating performance decreases. If you don't do this, you won't easily reach the end of your life. This property is very convenient when used in an actual machine because stops and starts are repeated. Furthermore, the grease composition of the present invention exhibits excellent load-bearing performance due to the calcium compound, and excellent adhesion due to the organic acid group of the N-alkyl-substituted calcium monoaminate. This is thought to be the reason. In addition, the present invention contains rust preventive agents such as petroleum sulfonic acid alkali salts, which are generally used as grease additives, antioxidants such as salicylic acid and alkali salts, extreme pressure additives such as dialkyldithiophosphates, and pigments. It can also be changed. Specific implementation methods and effects of the present invention are shown in Examples 1 to 8 and Comparative Examples 1 to 3 (described below and Table 1). Example 1 (Production method A) 196.1 g of sebacic acid and 72.1 g of hydrogenated beef tallow amine (trade name Armin HT, manufactured by Lion Armor) were placed in a stainless steel jug and heated to 200°C and held for 0.5 hours to separate the N-alkyl-substituted monoamide and Prepare a mixture of reacted sebacic acid, add 669.3 g of paraffinic mineral oil (P) (17.2 centistokes, 100°C, viscosity index () 98), and further add 62.5 g of Ca(OH) ₂
90-100 after adding as a 1:1 water slurry
Saponified at ℃. After confirming the completion of saponification by IR,
After heating to 200°C, the mixture was cooled to room temperature and milled using a three-roll mill to obtain grease. Example 2 (Production method B) 200 g of calcium sebacate and 100 g of N-octadecyl calcium sebamate were added to 700 g of the same mineral oil (P) as in Example 1, heated to 200° C., and then cooled. After cooling, it was milled using a three-roll mill to obtain grease. Example 3 (Production method C) 108.7 g of N-octadecyl sebamic acid was added to 800 g of the same mineral oil (P) as in Example 1, and further Ca
(OH) ₂ Add 9.0g of 1:1 water slurry, 90~
After saponification at 100°C (IR confirmation) and dehydration by heating to 150°C, 82.3 g of calcium sebacate was added, heated to 200°C, and then cooled. After cooling, it was milled using a three-roll mill to obtain grease. Examples 4 to 7 (Manufacturing method A) Greases were obtained in the same manner as in Example 1 using the formulations shown in Table 1. However, in Example 6, mineral oil (N) (18 centistokes 100°C,
40) was used. Example 8 (Manufacturing method B) Grease was obtained in the same manner as in Example 2 using the formulations shown in Table 1. The performance of the greases obtained in Examples 1 to 8 above is shown in Table 1 together with the performance of the conventional greases of Comparative Examples 1 to 3. From Table 1, it was confirmed that the lubricating grease composition of the present invention has excellent high-temperature lubrication life and load-bearing performance and can achieve the objects of the present invention. 【table】

Claims (1)

[Scope of Claims] 1. A lubricating grease composition characterized in that the lubricating oil contains 5 to 40% by weight of a calcium salt of a dibasic acid and a calcium salt of an N-alkyl-substituted monoamic acid as increasing agents. 2 The dibasic acid is HOOC (CH ₂ ) _o COOH (where n = 4
-18) One or two aliphatic dibasic acids represented by
The lubricating grease composition according to claim 1, which is a mixture of more than one species. 3. The lubricating grease composition according to claim 1, wherein the mono-ratio of calcium acid to 3N alkyl-substituted monoamic acid is from 1:0.3 to 1:8.