JPH03103498A - Lubricating oil composition - Google Patents

Abstract

PURPOSE:To obtain a new lubricating oil composition excellent in lubricating performance and dispersion stability of solid lubricants by blending a lubricating base oil with a melamine cyanurate solid lubricant and a lanolin fatty acid (salt) having a low acid value as essential components. CONSTITUTION:The objective composition obtained by blending (A) a lubricating base oil, composed of synthetic oils or mineral oils and having preferably >=200 deg.C boiling point and normally 5-3000cP viscosity at ambient temperature with (B) melamine cyanurate which is an organic white solid (preferably having 0.02-10mu average particle diameter and uniform particle diameter distribution) and (C) lanolin fatty acid (salt) having a low acid value as a nonaqueous dispersant as essential components and further, as necessary, (D) a liquid isoprene-based polymer having 5000-100000 molecular weight.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to novel lubricating oil compositions. More specifically, the present invention relates to a lubricating oil composition having excellent lubrication performance and solid lubricant dispersion stability.

[Conventional technology]

Conventional lubricating oil compositions include efforts to impart extreme pressure properties and friction resistance to lubricating oils by blending various solid or liquid additives with so-called lubricating oils, such as synthetic oils, mineral oils, animal and vegetable oils, etc. is being done. For example, the addition of black solid lubricants such as graphite and molybdenum disulfide to forging oil, press oil, drawing oil, machine oil, etc. is known and has already been put into practical use. Regarding motor oils, for example, JP-A No. 55-23148 discloses boron nitride, and JP-A No. 63-97693 discloses a silicone resin dispersed with a nonionic surfactant. Further, as dispersants for non-aqueous solid lubricants, for example, nonionic surfactants such as polyoxybrobylene alkyl ether and polyoxybrobylene alkyl phenyl ether are disclosed in JP-A-60-56760. ing.

[Problem to be solved by the invention]

However, in such conventional lubricating oil compositions, for example, when graphite or molybdenum disulfide is added, the oil becomes black and opaque, making it difficult to judge whether the oil has deteriorated or causing damage to processed products during use. Black stains occur due to adhesion, and improvements to this problem are desired. In addition, Teflon resin, boron nitride, fluorocarbon, silicone (M fat, etc.) are sometimes used as solid lubricants, and when added to lubricating oil, they are white powders, which is preferable because they improve the appearance. However, due to their high prices, they are only used for limited purposes. Furthermore, the nonionic surfactants disclosed above do not have sufficient dispersion stability as solid lubricants and form a sedimentary layer, so they are not completely satisfactory as lubricating oils. On the other hand, it has recently been known that melamine cyanurate powder is useful as a white solid lubricant for improving extreme pressure properties and friction resistance. However, melamine cyanurate powder is an organic solid lubricant and has poor affinity for oil, so its dispersion stability in lubricating oil is extremely poor and it aggregates, so even if it is added to lubricating oil to prepare a dispersion. However, it has the disadvantage that it settles within one day and turns into a hard cake.

[Means to solve the problem]

As a result of intensive research aimed at solving the above problems, the present inventors discovered a lubricating oil composition with extremely excellent long-term stability, which could not be achieved using conventional techniques, and completed the present invention. That is, a lubricating oil composition characterized by containing a solid lubricant of melamine cyanurate and a low acid value lanolin fatty acid and/or a low acid value lanolin fatty acid salt as essential components in a lubricating base oil consisting of synthetic oil or mineral oil. and the lubricating oil composition has a molecule ii of 5000 to 100
This is a lubricating oil composition characterized by adding 000 liquid isoprene-based polymer. (Requirements constituting the means) As the lubricating oil used in the present invention, any lubricating oil that is normally used as an oily lubricating oil can be used. Oils such as naphthenic hydrocarbon oils, mineral oils such as paraffinic hydrocarbon oils can be used. Furthermore, synthetic oils include synthetic hydrocarbon oils obtained from polymerization of olefins, alkylated aromatic oils obtained from alkylation reactions of aromatics, and higher alcohols with 8 to 22 carbon atoms as starting materials, and higher alcohols with 8 to 22 carbon atoms as starting materials. Higher fatty acid or carbon number 6-18
phenol having an alkyl or alkenyl group, and alkylene oxide adducts with these can be used. The polyether oil to which alkylene oxide has been added can be synthesized by a commonly known method. In addition, when used as a lubricating oil, an oil with low viscosity, strong lipophilicity, and high lubricating properties is good, so the number of moles of alkylene oxide added is 3.
It is preferably 0 mole or less. Furthermore, it is preferable to add brobylene oxide and/or butylene oxide to the alkylene oxide. This addition method may be random or block addition, but adding butylene oxide alone is particularly preferred. Furthermore, synthetic ester oils such as fatty acid esters of polyhydric alcohols, fatty acid esters of higher alcohols, fatty acid esters of lower alcohols, fatty acid esters of alkanolamines, and animal and vegetable oils can be used. The above lubricating oils can be used alone or in combination, and include those having a viscosity of 5 to 3000 cp at room temperature. Next: The solid lubricant used in the present invention includes melamine cyanurate, which is an organic white solid and is an addition reaction product of melamine and cyanuric acid. Melamine cyanurate is an organic white solid lubricant that was first discovered in Japan. The lubrication mechanism of this substance has not yet been fully elucidated, but it is thought to be due to the cleavage lamellar structure similar to molybdenum disulfide and graphite, and when added to lubricating oil, it significantly improves lubrication performance. Improvement can be obtained. The solid lubricant mentioned above is usually 20
The particle size is less than μ, but the average particle size is 0.02 to tOU.
It is preferable to use one with a uniform particle size distribution. On the other hand, the isoprene-based polymer used in the present invention is obtained by polymerizing isoprene and has a molecular ffi of 5000 to 10oo.
Examples include liquid polyisoprene oligomers designated as OO. It is preferable to use a polyisoprene oligomer that does not have a functional group in its molecule or a hydrogenated product. Furthermore, compounds having some carboxyl and hydroxyl functional groups in their molecules, or ether compounds and ester compounds derived from these can also be used. These can usually be manufactured by known methods. The isoprene polymer used in the present invention has a molecular weight of 50
If it is less than 00, no improvement will be seen in the dispersion stability of melamine cyanurate when used in combination with a low acid value lanolin fatty acid and/or a low acid value lanolin fatty acid salt. Also, molecule 1
If it exceeds 100,000, the viscosity is high and it is difficult to use, which is not preferable. As the non-aqueous dispersant of the present invention, low acid value lanolin fatty acids and low acid value lanolin fatty acid salts are used. The above-mentioned non-aqueous dispersant can be obtained from wool grease or lanolin fatty acid separated by agglomeration of lanolin. That is, a low-acid-value lanolin fatty acid or a salt thereof is used, which is obtained by lowering the acid value of a lanolin fatty acid mixture consisting of the constituent components shown in Table 1 through a high-temperature dehydration reaction. (Left below) Its acid value and chemical value are usually 130 to 160, respectively.
, 160 to 180. As can be seen from the above composition, the main components of lanolin fatty acids are higher fatty acids having a very wide distribution of carbon numbers of 9 to 32, and α-hydroxy fatty acids having 12 to 25 carbon atoms. Therefore, low acid value lanolin fatty acids can be obtained by heating lanolin fatty acids without a catalyst or in the presence of any esterification catalyst, preferably at a temperature within the range of 160 to 220° C., under reduced pressure until the required acid value is reached. In addition, by heating such lanolin fatty acid containing hydroxy fatty acid under reduced pressure, two molecules of water are dehydrated from the lanolin fatty acid, resulting in lactide, or cyclic ester such as lactone due to intramolecular dehydration, and linear monoboly, It is known that esters are produced. The acid value of the low acid value lanolin fatty acid described above is preferably less than 125 mg-KOJI/g<90, more preferably 11
The value is smaller than 5 and larger than 100. If the acid value is outside this range, the dispersibility will be poor, so it is important to control the acid value. In other words, due to the high-temperature dehydration state of lanolin fatty acids, it has a special structure consisting of esters of hydroxyl groups related to hydroxy fatty acids and carboxyl groups of fatty acids consisting of branched alkyl groups with a very wide distribution, and is compatible with lubricating oil dispersion media and melamine resin. It is thought that the effect of improving the affinity for amerate appears and good results are obtained. Alternatively, the above esterification reaction can be carried out by dissolving the lanolin fatty acid in lubricating oil in advance. Salts of such low acid value lanolin fatty acids are also effective. Examples of salts include alkali metals such as sodium, potassium, and lithium, calcium, barium, magnesium,
Examples include alkaline earth metals such as lead and zinc. Furthermore, salts such as ammonia or amines may be used. Examples of amines include alkylamines, polyamines such as ethylenediamine, diethylenetriamine, and triethylenetetramine, morpholine, biperidine, and alkanolamines. Such a neutralization reaction can be obtained by heating and stirring a low acid value lanolin fatty acid and a base commensurate with the acid value at a temperature of up to 200°C. In this case, the reaction is preferably carried out in an organic solvent, for example in a lubricating oil such as a petroleum fraction. Furthermore, it is recommended to remove unreacted metal oxides and hydroxides by filtration, etc. Abrasion resistance, abrasion t? In terms of R relaxation, the salt is preferably an alkaline earth metal. These lanolin fatty acids and their salts may be used as a mixture of 2 fffi or more. The concentration of melamine cyanurate in the lubricating oil composition may be any concentration that produces a dispersion, but is usually 0.05 to 4.
0! ! Most of the content is 11%, and if it is less than 0.05% by weight, satisfactory lubrication performance cannot be obtained, whereas if it is more than 40% by weight, it is economically unfavorable. Further, it is desirable to add the dispersant in an amount of 0.1 to 20% by weight, preferably 0.5 to 10% by weight, based on the entire lubricating oil composition. As a method for producing a lubricating oil composition, for example, a predetermined amount of melamine cyanurate is added to a lubricating oil in which a dispersant is dissolved, and then a shearing force is applied to an extent that can break up the secondary particles of melamine cyanurate. The mixture is sufficiently stirred and mixed using a dispersing machine such as a three-roll mill, colloid mill, homogenizer, ball mill, line mixer, etc. The lubricating oil composition of the present invention may optionally contain antioxidants, rust inhibitors, corrosion inhibitors, antifoaming agents, load-bearing additives, demulsifiers,
A detergent dispersant and a known dispersant other than those of the present invention can also be used in combination.

[Effect]

The lubricating oil composition thus obtained has excellent dispersion stability of melamine cyanurate, and even when left for a long period of time, for example, 6 months or more,
It has excellent stability even at high temperatures such as ℃. Furthermore, the lubricating oil composition of the present invention has good extreme pressure properties and a low coefficient of friction, and can be used as a lubricating oil for general machinery, such as refrigeration oil, various engine oils, spindle oil, dynamo oil, machine oil,
When mixed with turbine oil, gear oil, cylinder oil, and various other hydraulic oils, it prevents seizure even under severe conditions and is highly effective in reducing the amount of wear on sliding surfaces. Furthermore, it is effective as a metal processing oil, a lubricating oil for processing fiber plastics, etc. When the lubricating oil composition of the present invention is used in these processing steps, graphite,
Since it is not a black liquid like molybdenum disulfide, there is no black contamination caused by adhesion to products or machines or workplaces, making it possible to make products much cleaner. EXAMPLES Hereinafter, the present invention will be described in more detail by describing examples, but the present invention is not limited to these examples.

【Example】

After dissolving a separating agent in various lubricating oils, melamine cyanurate was added and thoroughly mixed in a bead mill using 1 mm diameter glass beads to uniformly separate the lubricating oil compositions shown in Table 2. Ta. The lubricating oil composition prepared here was transferred to a 200 ml graduated cylinder, stored in a constant temperature bath at 25°C for 180 days, and the liquid in the cylinder was observed, and the appearance of liquid separation or hard sedimentation was evaluated using the following evaluation criteria. Dispersion oral stability was determined. Furthermore, as a separate evaluation of the sliding properties of the lubricating oil composition, the friction coefficient and limit load were measured using a Farex tester, and the results are shown in Table 3. 0: No liquid separation or sediment observed ○: Slight liquid separation, but no sediment observed Δ: Slight liquid separation, some soft sediment observed ×: Much liquid separation, hard Many sediments are observed (blank below). The above test results show that the lubricating oil composition of the present invention has excellent long-term stability, friction coefficient, and load resistance. It was done. Furthermore, it was found that a good lubricating oil could be obtained with less adhesion and contamination caused by the lubricating oil.

【Effect of the invention】

Products using melamine cyanurate as a solid lubricant are powder products and viscous grease-like products, and the separation solution of non-aqueous solvents has strong cohesive properties, making it difficult to manufacture. However, by completing the lubricating oil composition of the present invention, a dispersion product with low viscosity and high stability can be obtained, and it has good handling properties.
Because it has excellent lubricity and allows the use of new lubricating oils at low cost, it has widely contributed to industrial development in the metal and machinery industries by providing lubricating oil materials.

Claims (1)

[Claims] 1. A lubricating base oil made of synthetic oil or mineral oil contains a solid lubricant of melamine cyanurate and a low acid value lanolin fatty acid and/or a low acid value lanolin fatty acid salt as essential components. A lubricating oil composition. 2. The lubricating oil composition according to claim 1 has a molecular weight of 5000 to
A lubricating oil composition characterized in that 100,000% of a liquid isoprene-based polymer is added.