CN102124087A - Grease composition - Google Patents

Abstract

A grease composition for resin lubrication incorporated into a grease base material, said composition comprising a base oil and a thickener, at least one saturated or unsaturated fatty acid having 8 to 22 carbon atoms and/or Or a fatty acid metal salt, the fatty acid metal salt is a metal salt of a straight-chain saturated fatty acid with 8-14 carbon atoms or a metal salt of an unsaturated fatty acid with 16-22 carbon atoms and 1-4 unsaturated groups , the metal has a valence of 1-4, wherein the thickener does not include the fatty acid metal salt.

Description

grease composition

technical field

The present invention relates to a grease composition for resin lubrication for a lubrication point where rolling or sliding occurs when a resin material is used.

Background technique

In recent years, the use of resin materials for components in various industrial machines (especially in the automotive industry) has become prominent in terms of many aspects such as lighter weight, lower cost, lower friction or recyclability. However, due to the diversity of the structural elements of the assembly, many new problems have arisen, and all technologies are left to be improved.

For example, in the following parts, there are lubrication points where resin and resin or resin and non-resin materials such as metal act through contact: moving parts of electric door mirrors or sliding parts of telescopic shafts of car steering wheels, R&P steering rack guides Various sliding parts, power transmission gears of electric power steering equipment, internal sliding parts of various brakes and cylinders, linear guides and ball screw brackets of various mechanical tools, various bearing cages, sliding parts of crane frame arms, and Resin gear parts in various audio machines such as broadcast tape players, video recorders and CD players, resin gear parts in office automation equipment such as printers, copiers and facsimile machines, and sliding parts in various electric switches.

So far, in the field of lubrication, almost all mechanical structural components are metal materials, so the research on the friction and wear between metals such as iron, aluminum, their alloys, brass and bronze has a long and extensive history. This extensive experience and knowledge has accumulated many technologies.

For example, extreme pressure and anti-wear agents containing elements such as phosphorus or sulfur are known to be effective in resisting metal-to-metal friction and wear, and these additives form films that pre-initiate contact with the metal surface. The chemical reaction, thereby reducing friction and wear and preventing mechanical seizure. This technology is widely used in engine oils and gear oils as well as high performance industrial lubricants and greases.

But despite the short history of resin-to-resin or resin-to-dissimilar materials such as metal lubrication technology, their applications mentioned above have been extensive in recent years, but the current situation is that in this diversification process Among them, no technology capable of fully satisfying various requirements for grease has been proposed.

For example, when a technique of applying phosphorus or sulfur additives effective for friction and wear in the aforementioned metal-to-metal case at the lubricating points of resin and metal materials, the friction-reducing effect achievable with metal-to-metal is not actually obtained. In fact, there are definitely instances where friction and wear properties are degraded and the life of mechanical parts is shortened.

It is thought that this is due to the fact that the resin surface is much weaker chemically than metal, there is little reaction between the friction surface and organic additives such as those based on phosphorus or sulfur, and assuming that the adsorption is also weak, the effects on friction and wear The effect is also insignificant, and thus the friction reducing effect is also weak. In addition, when they are applied in the range of intentionally elevated temperatures, the active sulfur and phosphorus in these additives penetrate into the resin components, thus causing cracking and embrittlement. There are also cases where the opposite effect of friction and wear is promoted.

In order to improve the aforementioned lubricating state between resin and resin or between resin and different materials such as metal, a grease for resin lubrication has been proposed (Japanese Laid-Open Patent No. 2002-371290), so that by The montan wax is added to the lubricating grease composition to reduce the static friction coefficient of the lubricating parts and strengthen the durability and life of the lubricating parts. In addition, a technique has been disclosed (Japanese Laid-Open Patent No. 2003-246996) in which the oxidation of grease is improved by adding a phenolic rust inhibitor composed of only atoms of three elements, carbon, oxygen, and hydrogen, to the grease Stability and rust protection of metal parts without detrimental effects such as stress cracking on resinous lubrication point materials or resinous packaging materials. Expect further improvements.

The present invention seeks to obtain a grease composition for resin lubrication in which friction is reduced and satisfactory lubricating performance is obtained at lubrication points where rolling and sliding etc. occur, in which a paired structure such as resin and resin or resin At least one side with a different material such as metal contains a resin material.

After having studied and examined the lubricating behavior of resins based on surface chemistry theory in the past, the inventors have arrived at the present invention by finding that: The extremely weak charge interacts with some saturated or unsaturated fatty acids and fatty acid metal salts added to the grease, and further these additives exhibit the function of bonding agent with the grease, so that it is possible to combine resin with resin or paired A more reliable lubricating film is formed and maintained on the surface of the material, resulting in reduced friction and satisfactory lubrication.

Contents of the invention

The present invention is a grease composition for resin lubrication incorporated into a grease base material, said composition comprising a base oil and a thickener, at least one saturated or unsaturated fatty acid having 8 to 22 carbon atoms and / or fatty acid metal salt, the fatty acid metal salt is a metal salt of a straight-chain saturated fatty acid with 8-14 carbon atoms or a metal salt of an unsaturated fatty acid with 16-22 carbon atoms and 1-4 unsaturated groups salt, the metal has a valence of 1-4, and wherein the thickener does not include the fatty acid metal salt.

Preferably, the metal of the fatty acid metal salt includes metals such as lithium, sodium, potassium, magnesium, calcium, zinc, aluminum and lead.

It is preferred that the total amount of saturated or unsaturated fatty acids and/or fatty acid metal salts used be of the order of 0.1-10% by weight. In addition, urea, bentonite, calcium phosphate or sodium p-formobenzoate and other thickeners can be used as grease thickeners alone or in mixtures.

According to the present invention, friction is reduced so that satisfactory lubricating performance can be obtained at lubricating points such as rolling and sliding points between parts comprising resinous materials, and the composition can be widely used as a lubricant for resinous lubrication. Grease composition.

Detailed ways

In the present invention, the base oil may be a substance generally usable as a lubricating oil base oil or a grease base oil, and is not particularly limited. Mention may be made, by way of example, of mineral oils, synthetic oils, animal and vegetable oils, and mixtures thereof.

In particular, base oils belonging to API (American Petroleum Institute) base oil classification Group I, Group II, Group III, Group IV, etc. may be used alone or as a mixture.

Group I base oils include, for example, paraffinic mineral oils obtained by appropriate combinations of refining processes such as solvent refining, hydrofinishing, and dewaxing for lubricating oil fractions obtained by atmospheric distillation of crude oil.

Group II base oils include, for example, paraffinic mineral oils obtained by appropriately combining refining processes such as hydrofinishing and dewaxing for lubricating oil fractions obtained by atmospheric distillation of crude oil. Group II base oils refined by hydrofinishing processes such as the Gulf Company's process have a total sulfur content of less than 10 ppm and an aromatics content of no greater than 5% and are therefore suitable for use in the present invention.

Group III base oils and Group II+ base oils include paraffinic mineral oils prepared by highly hydrofinishing lube oil fractions obtained by atmospheric distillation of crude oil, by isomerization dewaxing Waxes produced by the alkane substitution dewaxing process) refined base oils, and base oils refined by the Mobil wax isomerization process. These also apply in the present invention.

Specific examples of synthetic oils include polyolefins, polyoxyalkylene glycols such as polyethylene glycol or polypropylene glycol, esters such as di-2-ethylhexyl sebacate or di-2-ethylhexyl adipate , Polyol esters such as trimethylolpropane ester or pentaerythritol ester, perfluoroalkyl ether, silicone oil, polyphenylene ether, etc.

The aforementioned polyolefins include polymers of various olefins or their hydrogenated products. Any olefin may be used, and as examples may be mentioned ethylene, propylene, butene and α-olefins having 5 or more carbons. In producing polyolefins, the aforementioned olefins may be used alone or in combination of two or more. Particularly suitable are polyolefins known as poly-alpha-olefins (PAO). These are Group IV base oils.

GTL (gas-to-liquids) base oils synthesized by the Fischer-Tropsch process of converting natural gas into liquid fuels have very low sulfur and aromatic content compared to mineral oil base oils obtained from crude oil refining, and have very high chain Alkanes composition ratio, and therefore have very good oxidation stability, and because they also have very little evaporation loss, they are suitable for use as the base oil of the present invention.

As typical examples of animal and vegetable oils, mention may be made of castor oil and rapeseed oil.

The aforementioned various oils may be used alone or in admixture as the base oil. The aforementioned examples are listed individually, but the present invention is not limited thereto.

As for the thickener contained in the aforementioned base oil, thickeners other than fatty acid metal salt thickeners such as bentonite, clay, silicon dioxide, tricalcium phosphate, calcium sulfonate complex, urea, sodium p-formylbenzoate and Other thickeners can be used alone or in mixtures.

The aforementioned metal salts of fatty acids are substances in which fatty acids and metals are bonded, and they are generally called metal soaps. As illustrative examples, mention may be made of lithium soaps, sodium soaps, potassium soaps, magnesium soaps, calcium soaps, barium soaps, aluminum soaps, zinc soaps, lead soaps and complex soaps thereof.

In specific cases, the aforementioned thickeners can also be used together with fatty acid metal salts as the thickener, but in this case, it is usually preferable to use a fatty acid metal salt different from the fatty acid metal salt used as an additive.

Additives added to the grease base material comprising the aforementioned base oil and thickener are metal salts of saturated or unsaturated fatty acids having 8 to 22 carbon atoms and/or linear saturated fatty acids having 8 to 14 carbon atoms Or a metal salt of an unsaturated fatty acid having 16-22 carbon atoms and 1-4 unsaturated groups, and wherein the metal has a valence of 1-4.

As examples of fatty acids which form the starting materials of the aforementioned saturated or unsaturated fatty acids and fatty acid metal salts in the present invention, there may be mentioned caprylic acid, nonanoic acid, capric acid, lauric acid, dodecenoic acid, myristic acid, crude Renic Acid, Spermcetenoic Acid, Myristoleic Acid, Pentadecanoic Acid, Palmitic Acid, Palmitoleic Acid, Heptadecanoic Acid, Stearic Acid, 12-Hydroxystearic Acid, Coriander Acid, Oleic Acid, Elaid Oil Acid, 11-octadecenoic acid, linoleic acid, linolenic acid, 9,11,13-octadecatrienoic acid, mycobacterium stearic acid, arachidic acid, eicosadienoic acid, eicosane arachidonic acid, arachidonic acid, docosanoic acid, lignoceric acid, nervonic acid, hexacanoic acid, octacosanoic acid, and sinapinic acid.

In the present invention, the aforementioned saturated or unsaturated fatty acids are preferably those having 8-22 carbon atoms, and for fatty acid metal salts, preferably linear saturated fatty acid salts having 8-14 carbon atoms or having 16-22 Metal salts of unsaturated fatty acids with carbon atoms.

If the metal in the fatty acid metal salt of the present invention is lithium, sodium, potassium, magnesium, calcium, zinc, aluminum, lead, etc., the effect of reducing friction between materials at the lubrication point between resin and non-resin materials is very large Large, and these metals and fatty acids can easily react. Fatty acid salts are also chemically stable, and readily maintain the preferred lubricating conditions.

For the total amount of the aforementioned saturated or unsaturated fatty acids or one or more aforementioned fatty acid metal salts, it is best to add them in an amount of 0.1-10% relative to the total amount of the grease composition, and preferably their amount It is 1-5wt%. If they are present in an amount of less than 0.1% by weight, the electrochemical action on the surface is too small, and the effect of lowering the friction coefficient is too low. If the fatty acid or fatty acid metal salt is present in an amount greater than 10 wt%, it is difficult to effectively verify the basic properties of the grease composition (such as viscoelasticity, shear stability, heat resistance, etc.), and it may be difficult to maintain a stable state for a long time. Costs will also rise.

In addition, antioxidants, rust inhibitors, oiliness agents, extreme pressure additives, anti-wear agents, solid lubricants, metal deactivators, polymers and other additives may be suitably added to the grease composition of the present invention.

Antioxidants include, for example, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-p-cresol, P,P'-dioctyldiphenylamine, N- Phenyl-α-naphthylamine, phenothiazine, etc.

Rust inhibitors include paraffin oxides, carboxylate metal salts, sulfonate metal salts, carboxylate esters, sulfonate esters, salicylate esters, succinate esters, sorbitan esters and various amine salts.

Oily agents, extreme pressure additives, and anti-wear agents include, for example, sulfurized zinc dialkyldithiophosphates, sulfurized zinc diaryldithiophosphates, sulfurized zinc dialkyldithiocarbamates, sulfurized diaryl Zinc dithiocarbamate, sulfurized molybdenum dialkyldithiophosphate, sulfurized molybdenum diaryldithiophosphate, sulfurized molybdenum dialkyldithiocarbamate, sulfurized diaryldithiophosphate Molybdenum carbamate, organomolybdenum complex, sulfurized olefins, triphenylphosphate, triphenylthiophosphate, tricresylphosphate, other phosphates and sulfurized fats and oils.

The solid lubricant includes, for example, molybdenum disulfide, graphite, boron nitride, melamine cyanurate, PTFE (polytetrafluoroethylene), tungsten disulfide, mica, graphite fluoride, and the like.

Metal deactivators include N,N'-disalicylidene-1,2-diaminopropane, benzotriazole, benzimidazole, benzothiazole, thiadiazole and the like.

Since it is possible in the present invention to reduce friction and obtain satisfactory performance at a lubrication point where rolling and sliding between materials is significant, wherein one of the paired materials is composed of a resin, one of the paired materials must be a resin, but The part paired with the resin can be not only various metal materials such as iron, copper, aluminum or other metals or their alloys, but also rubber or glass, or non-polar substances such as ceramics, so they can be free of Wide application with special restrictions.

In addition, general plastics or engineering plastics can be arbitrarily applied to the aforementioned resin substance, and as examples there can be mentioned polyamide, polyacetal, polycarbonate, polyethylene terephthalate, polybutylene terephthalate Glycol ester, polybutylene naphthalate, polyphenylene ether, polyphenylene sulfide, fluorinated resin, polyacrylate, polyamideimide, polyetherimide, polyether ether ketone, polysulfone, Polyethersulfone, polyimide, polystyrene, polyethylene, polypropylene, phenol resin, AS resin, ABS resin, AES resin, AAS resin, ACS resin, MBS resin, polyvinyl chloride resin, epoxy resin, di Allyl phthalate resins, polyester resins, methacrylate resins, and ABS/polycarbonate alloys, but not limited to these.

Example

The present invention is explained in further detail below by way of examples and comparative examples, but the present invention is by no means limited to these examples.

Prepare following materials for embodiment and comparative example:

1. Base oil A: mineral oil having a kinematic viscosity of 101.1 mm ² /s at 40°C.

2. Base oil B: poly-alpha olefin oil having a kinematic viscosity of 31.2 mm ² /s at 40°C.

3. Base oil C: a highly refined oil with kinematic viscosity at 40°C of 47.08 mm ² /s, viscosity index of 146, %CA of less than 1, %CN of 11.9 and %CP of not less than 85.

4. Thickener A: diurea obtained by the synthesis reaction of 2mol octylamine and 1mol MDI (4,4'-diphenylmethane diisocyanate) in base oil.

5. Thickener B: bentonite obtained by swelling bentonite in base oil with an organic solvent and then gelling.

6. Thickener C: a substance obtained by gelling after swelling a hydroxyapatite/tricalcium phosphate complex represented by [Ca ₃ (PO ₄ ) ₂ ] ₃ ·Ca(OH) ₂ with an organic solvent.

7. Thickener D: Sodium p-formylbenzoate obtained by reacting methyl N-octadecyl p-formylbenzoate and sodium hydroxide in base oil.

Greases were prepared in kettles using base oils and thickeners in the proportions shown for Examples 1-24 in Tables 1-5, and grease compositions were obtained by adding various fatty acids and/or fatty acid metal salts.

In specific details, for the greases using thickener A (urea) in Examples 1, 3-9, 12-14, 20 and 23, first weigh the base oil, Thickener A and various fatty acids or fatty acid metal salts as additives, so that the total amount of the grease composition is 1000 g. A paste of part of the base oil and thickener A in MDI (4,4'-diphenylmethane diisocyanate) was then added to a kettle with a capacity of 3 kg dedicated to the preparation of grease. With heating and stirring, the temperature was raised to 60°C, and the reaction was carried out by forming a paste and adding octylamine premixed and dissolved in the remaining base oil. After the temperature was further increased to 180°C, cooling was performed at a constant rate. The aforementioned fatty acid or fatty acid metal salt was added as a paste, and after homogenizer treatment, the grease composition for resin lubrication for each example was obtained.

The fatty acid metal salts specified in Tables 3-5 were used after they were obtained by first reacting fatty acids with metals in the molar ratios specified in Tables 3-5 (and similarly in the description below).

For the grease compositions using thickener B (bentonite) in Examples 2, 10, 15 and 17, first weigh the base oil, thickener B and each A fatty acid or a fatty acid metal salt, so that the total amount of the composition is 1000 g. Then base oil and bentonite and an organic solvent that promotes gelation to form a paste are added to a kettle with a capacity of 3 kg specially used for the preparation of lubricating grease. Under the condition of heating and stirring, the temperature was gradually increased to 150° C., and as the organic solvent volatilized, it diffused uniformly to perform swelling. Cooling is then performed at a constant rate. The aforementioned fatty acid or fatty acid metal salt was added as a paste, and after homogenizer treatment, the grease composition for resin lubrication for each example was obtained.

For the grease composition using thickener C (tricalcium phosphate) in Example 19, first weigh the base oil, thickener C and fatty acid metal salt as an additive in the ratio shown in Table 4, so that the combination The total amount of the substance is 1000g. Then the base oil and tricalcium phosphate and the organic solvent that promotes gelation to form a paste are added to a kettle with a capacity of 3kg specially used for the preparation of lubricating grease. Under the condition of heating and stirring, the temperature was gradually increased to 150° C., and as the organic solvent volatilized, it diffused uniformly to perform swelling. Cooling is then performed at a constant rate. The aforementioned fatty acid metal salt was added as a paste, and after being treated with a homogenizer, the grease composition for resin lubrication for this example was obtained.

For the grease composition of the application thickener D (sodium p-formylbenzoate) of embodiment 21, first weigh base oil, thickener D and the fatty acid metal salt as additive in the ratio shown in Table 5, thereby The total amount of the grease composition was 1000 g. Then base oil and methyl N-octadecyl p-formylbenzoate as the raw material of thickener D are pasted into a kettle with a capacity of 3 kg specially used for the preparation of grease. Under the condition of heating and stirring, at a temperature of 90°C, the sodium hydroxide suspension that had been previously stirred and dispersed in water was mixed into the kettle and reacted while heating and stirring to gradually increase the temperature to 170°C. Cooling is then performed at a constant rate. The aforementioned fatty acid metal salt was added as a paste, and after being treated with a homogenizer, the grease composition for resin lubrication according to Example 21 was obtained.

For the grease composition using a mixed thickener in Examples 11, 16, 18, 22 and 24, in a kettle specially used for preparing grease, the grease prepared by the method for the aforementioned thickener was placed in Mix at room temperature in the proportions shown in Tables 3-5. Fatty acid or fatty acid metal salt was added as a paste, and after homogenizer treatment, the grease composition for resin lubrication for each example was obtained.

For Comparative Examples 1-10, the various raw materials were weighed out according to the proportions shown in Tables 6-7, and grease compositions were prepared according to the method described for the previous examples.

For comparing the characteristics and performances of the examples and comparative examples, the following measurements and tests were carried out:

1. Penetration: measured according to JIS K2220-7;

2. Dropping point: measured according to JIS K2220-8;

3. Kinematic viscosity of base oil: measured according to JIS K2283;

4. Friction test: A Bowden type friction test is performed. In other words, the coefficient of friction between a resin (test material 1b) and a pair of materials different from the resin (test material 1a) was measured using a Bowden friction test apparatus under the following test conditions:

(1) Test material 1a:

Material - Copper alloy ALBC2 and steel S45C.

Dimensions - Pin shape with outer diameter 5.0mm and length 24mm, tip hemispherical with r = 2.5mm, and contact surface machined to a smooth area of approximately 1.0mm diameter.

(2) Test material 1b:

Materials - polyacetal resin (Delrin 500P by Dupont) and polyamide resin (66Nylon/Amilan by Toray)

Dimensions - Plate length 200mm and width 52mm.

(3) Temperature: 25°C.

(4) Sliding rate: 1.0mm/s.

(5) Load: 870g

(6) Surface pressure of the contact surface: 10MPa

Bowden friction tests were performed for all examples and all comparative examples for polyamide resin and steel pairings, and selectivity for polyacetal resin and copper alloy pairings.

Test Results

The results of these tests are shown in Tables 1-7.

discuss

The grease compositions for resin lubrication of Examples 1-24 all exhibited semi-solid grease characteristics, and exhibited medium hardness penetration values of 266-297, while dropping points were not satisfactorily low at 260°C. In addition, the friction coefficient between polyamide resin and steel in the Bowden friction test is 0.059-0.067, while the friction coefficient between polyacetal resin and copper alloy is uniformly lower value of 0.058-0.064, so it is obvious that Exhibits satisfactory lubricity between various resins and non-resin materials such as steel and alloys.

On the other hand, the grease compositions of Comparative Examples 1-10 all exhibited semi-solid grease characteristics, and the penetration values representing hardness were 269-293, while the dropping point was also satisfactorily not lower than 263°C , but in the Bowden friction test, the coefficient of friction between polyamide resin and steel is 0.088-0.118, while the coefficient of friction between polyacetal resin and copper alloy is a higher value of 0.096-0.121, so it is obvious that for Lubrication states between various resins and non-resin materials such as alloys or steels, which were inferior to the examples of the present invention, and no effect of improving lubricity was obtained.

From these results, it can be seen that the grease composition for resin lubrication of the present invention exhibits satisfactory lubricating performance.

Table 1

Table 2

table 3

Table 4

table 5

Table 6

Table 7

Claims (4)

1. grease composition that is used for resin lubrication that is attached in the lubricating grease base mateiral, described composition comprises the saturated or unsaturated fatty acids and/or the fatty acid metal salt of base oil and thickening material, at least a 8-22 of a having carbon atom, described fatty acid metal salt be have 8-14 carbon atom linear saturated fatty acids metal-salt or have the metal-salt of the unsaturated fatty acids of 16-22 carbon atom and 1-4 unsaturated group, described metal has the valency of 1-4, and wherein said thickening material does not comprise described fatty acid metal salt.

2. the grease composition that is used for resin lubrication of claim 1, the metal of wherein said fatty acid metal salt is lithium, sodium, potassium, magnesium, calcium, zinc, aluminium or lead.

3. claim 1 or 2 the grease composition that is used for resin lubrication, wherein with respect to the total amount of grease composition, one or more total contents saturated or unsaturated fatty acids and/or fatty acid metal salt are 0.1-10wt%.

4. each the grease composition that is used for resin lubrication of claim 1-3 wherein comprises at least a as thickening material in urea, wilkinite, calcium phosphate or the p formyl benzoic acid sodium.