WO2017126703A1

WO2017126703A1 - Lubricant composition for resins and method for lubricating resins

Info

Publication number: WO2017126703A1
Application number: PCT/JP2017/002117
Authority: WO
Inventors: 宏典竹内; 設楽　裕治
Original assignee: Ｊｘエネルギー株式会社
Priority date: 2016-01-22
Filing date: 2017-01-23
Publication date: 2017-07-27
Also published as: JPWO2017126703A1; JP6889664B2

Abstract

A lubricant composition for resins that has high lubricity, especially a low friction coefficient, and further improved abrasion resistance when lubricating a resin sliding part, and a lubricating method using the same. In a lubricant composition for resins containing a carboxylic acid derivative that includes an amide bond and a carboxyl group in the same compound, the carboxylic acid derivative is preferably a compound represented by the following general formula (1) or general formula (2). R¹-(C=O)-(N-R²)-A-(C=O)-OH ⋅ ⋅ (1), R¹-(N-R²)-(C=O)-A-(C=O)-OH ⋅ ⋅ (2) (In the formulas, R¹ is a monovalent hydrocarbon group, R² is a hydrogen or a monovalent hydrocarbon group, and A is a divalent hydrocarbon group; these hydrocarbon groups may include oxygen-containing groups) and a method for lubricating a resin in which this is interposed on the surface of the resin.

Description

Lubricant composition for resin and resin lubrication method

The present invention relates to a resin lubricant composition for use in a sliding portion between resins, in particular, synthetic resins such as polyamide resin and polyoxymethylene resin, or between resin and metal, ceramic, and the like, and a resin lubrication method using the same. About.

In order to lubricate sliding parts such as metal parts, various lubricants such as lubricating oils and greases in which additives such as oiliness agents and extreme pressure agents are blended with a lubricating base oil are used. In recent years, parts made of synthetic resin are frequently used because of weight reduction of parts and ease of processing.

Such lubrication of the resin sliding portion is greatly different from that of metal, and satisfactory properties cannot be exhibited with a metal lubricant, and lubricating base oils and additives have been studied. For example, a grease using an amine salt of an unsaturated fatty acid as an additive on a grease base material containing a base oil and a thickener is known. (See Patent Document 1). A composition containing 3 to 25% by mass of a silicone oil and a lithium soap thickener, 3 to 25% by mass of polytetrafluoroethylene resin powder, and 1 to 15% by mass of saturated fatty acid amide has been proposed (see Patent Document 2).
Furthermore, the present applicant has proposed a grease composition containing a specific lubricating base oil, an amide compound, a solid lubricant, and a metal soap thickener (see Patent Document 3).
However, these lubricants are insufficient in terms of lubricity, particularly wear resistance. In order to improve the wear resistance, it is necessary to reduce the sliding frictional heat. For this purpose, further improvement of the low friction coefficient by a lubricant has been desired.

JP 2010-106256 A JP 2011-225781 A JP 2013-181154 A

The problem to be solved by the present invention is to provide a resin lubricant composition having a high lubricity, particularly a low friction coefficient, and further improving the wear resistance of the resin in the lubrication of the resin sliding portion, The object is to provide a lubrication method using this.

As a result of earnestly researching the present inventors in order to solve the above problems, as a result of resin lubrication, a compound having both a specific polar group, that is, an amide bond and a carboxyl group, in one compound. Has been found to significantly reduce the coefficient of friction.
This invention is made | formed based on this knowledge, and consists of the following.

[1] A lubricant composition for a resin comprising a lubricant base oil and an amide bond and a carboxylic acid derivative containing a carboxyl group in the same compound.
[2] The resin lubricant composition according to the above [1], wherein the carboxylic acid derivative is represented by the following general formula (1) or general formula (2).
R ^1- (C═O) — (N—R ² ) —A— (C═O) —OH (1)
R ^1- (N—R ² ) — (C═O) —A— (C═O) —OH (2)
Here, R ¹ is a monovalent hydrocarbon group, R ² is hydrogen or a monovalent hydrocarbon group, A is a divalent hydrocarbon group, and these hydrocarbon groups are oxygen-containing groups. May be included.
[3] In the general formula (1) or (2), R ¹ is an alkenyl group having 4 to 24 carbon atoms, R ² is hydrogen or an alkyl group having 1 to 8 carbon atoms, and A is carbon. The resin lubricant composition according to the above [2], which is an alkylene group of several 1 to 8.
[4] The resin lubricant composition according to the above [2], wherein in the general formula (1) or (2), R ¹ is a hydrocarbon group containing an ester bond having 4 to 24 carbon atoms.
[5] The resin lubricant composition according to any one of [1] to [4], which is used for lubricating a resin containing at least one of a polyamide resin and a polyoxymethylene resin.
[6] The resin lubricant composition according to any one of the above [1] to [5], wherein the lubricant base oil is a hydrocarbon oil.
[7] The resin lubricant composition according to any one of [1] to [6] above, further containing a thickener and being a grease.
[8] The resin lubricant composition according to any one of [1] to [7] above, wherein the total content of the carboxylic acid derivative is 0.02 to 20% by mass based on the total amount of the lubricant composition. object.
[9] A resin lubrication method in which a lubricant composition containing a lubricant base oil and an amide bond and a carboxylic acid derivative containing a carboxyl group in the same compound is interposed on the surface of the resin.

The lubricant composition of the present invention makes it possible to stably reduce the coefficient of friction for a long period of time in lubrication between resins or between a resin and a sliding member other than a resin such as a metal or ceramic. In addition, the resin as a sliding member is excellent in stick-slip resistance and has a special effect that high reliability is possible over a long period of time.

[Lubricant base oil]
As the lubricating base oil of the present invention, either a mineral oil or a synthetic oil can be used, preferably having a kinematic viscosity at 40 ° C. of 1 to 1000 mm ² / s, more preferably 20 to 300 mm ² / s. . In order to prepare a lubricant having excellent lubricity, the viscosity index is 90 or more, particularly 95 to 250, the pour point is −10 ° C. or less, particularly −15 to −70 ° C., and the flash point is 150 ° C. or more. Those having the following physical properties are preferred.
Further, when the lubricant is grease, it is more preferable that the lubricant base oil has a density of 0.75 to 0.95 g / cm ³ at 15 ° C. because the dispersibility of the solid lubricant is high.

Mineral oil base oils include lubricating oil fractions obtained by purifying distillate obtained by subjecting crude oil to atmospheric distillation or further distillation under reduced pressure by various purification processes. The refining process includes hydrorefining, solvent extraction, solvent dewaxing, hydrodewaxing, sulfuric acid washing, clay treatment, etc., and by combining these in an appropriate order, the lubricating base oil of the present invention is treated. Obtainable. A mixture of refined oils having different properties, obtained by different crude oils or distillate oils by different process combinations and sequences, is also useful. Any method can be preferably used by adjusting the properties of the obtained base oil so as to satisfy the aforementioned physical properties.

As the synthetic lubricant base oil, it is preferable to use a substrate having excellent hydrolysis stability. For example, polyolefins such as poly-α-olefin, polybutene and copolymers of two or more kinds of olefins, polyesters, polyalkylenes, etc. Examples thereof include glycol, alkylbenzene, and alkylnaphthalene. Among these, poly-α-olefin is preferable in terms of availability, cost, viscosity characteristics, oxidation stability, and compatibility with system members. The poly-α-olefin is more preferably a polymer such as 1-dodecene or 1-decene in terms of cost.
The lubricating base oil used in the present invention is preferably a hydrocarbon oil such as mineral oil or poly-α-olefin.

As the lubricating base oil, the exemplified synthetic systems can be used alone or in admixture of two or more. Furthermore, it can also be used by mixing with the mineral oil system. When using a mixture of a plurality of lubricating base oils including a synthetic base oil, if the base oil mixture satisfies the above physical properties, the individual base oils before mixing are within the range of physical properties. It can be used even if it is off. Accordingly, the individual synthetic base oils do not necessarily satisfy the above physical properties, but are preferably within the above physical properties.
In the lubricating oil composition, the content of the lubricating base oil is the balance excluding the additive. In the grease composition, the content of the lubricating base oil is preferably 50 to 95% by mass, and preferably 60 to 90% by mass based on the total amount of the lubricant composition. % Is more preferable.

[Carboxylic acid derivative]
The carboxylic acid derivative serving as the blending component of the present invention is a compound containing an amide bond and a carboxyl group in the same compound. This type of compound is based on the examples and comparative examples of the present specification, and from our many years of experience and knowledge, two polar sites of amide bond and carboxyl group are strongly chemisorbed on the resin surface by hydrogen bond. It can be presumed that the oily effect is improved and the friction coefficient is reduced, and the effect of the present invention can be exhibited without any trouble as long as the compound contains an amide bond and a carboxyl group in the same compound.
Preferred specific compounds include those represented by the following general formula (1) or general formula (2).
R ^1- (C═O) — (N—R ² ) —A— (C═O) —OH (1)
R ^1- (N—R ² ) — (C═O) —A— (C═O) —OH (2)
In the general formulas (1) and (2), R ¹ is a monovalent hydrocarbon group, R ² is hydrogen or a monovalent hydrocarbon group, and A is a divalent hydrocarbon group. Yes, these hydrocarbon groups may contain oxygen-containing groups.

In General Formula (1) or General Formula (2), R ¹ is an alkenyl group having 4 to 24 carbon atoms, R ² is hydrogen or an alkyl group having 1 to 8 carbon atoms, and A is 1 to More preferably, it is an alkylene group having 8 carbon atoms, in particular, R ¹ is an alkenyl group having 12 to 20 carbon atoms, R ² is hydrogen or an alkyl group having 1 to 4 carbon atoms, and A is 1 carbon atom. Those having an alkylene group of 1 to 4 are preferred. Specific compounds include N-oleyl sarcosine, N-methyl-oleyl sarcosine (R ¹ : C 17, R ² : C 1, A: C 1), stearyl sarcosine (R ¹ : C 17, R ² : H, A: C1), N-methyl-stearyl sarcosine (R ¹ : C17, R ² : C1, A: C1), N-octyl-oleyl sarcosine (R ¹ : C17, R ² : C8, A: C1) N-lauryl-oleyl sarcosine (R ¹ : C17, R ² : C12, A: C1), N-lauryl-stearyl sarcosine (R ¹ : C17, R ² : C12, A: C1) and the like. .
Or, in general formula (1) or general formula (2), R ¹ is preferably a hydrocarbon group containing an ester bond having 4 to 24 carbon atoms (including further 1 to 24 carbon atoms). Methyl acid, octyl oleate, oleyl oleate, butyl succinate, octyl succinate, oleyl succinate, octyl azelate, octyl sebacate, oleyl sebacate, methyl phthalate, butyl phthalate, octyl phthalate, oleyl phthalate And more preferably a group formed by removing one hydrogen atom from oleyl terephthalate or the like.

The blending amount of the carboxylic acid derivative of the present invention is preferably 0.02 to 20% by mass, particularly 0.05 to 10% by mass, more preferably 0.1 to 5% by mass based on the total amount of the lubricant composition.

[Thickener]
Thickeners when the lubricant composition of the present invention is grease include soap-type thickeners such as metal soaps and composite metal soaps, benton, silica gel, urea-type thickeners (urea compounds, urea / urethane compounds) Any thickening agent such as a non-soap thickening agent such as a urethane compound can be used. Among these, a soap-based thickener and a urea-based thickener can be preferably used from the viewpoint of the effect of preventing damage on the lubricating surface.

Examples of the soap-based thickener include sodium soap, calcium soap, aluminum soap, lithium soap, and the like. Among these, lithium soap is preferable from the viewpoint of water resistance and thermal stability. Examples of lithium soaps include lithium stearate and lithium-12-hydroxystearate. As the fatty acid constituting the soap, for example, a saturated fatty acid, unsaturated fatty acid, hydroxy fatty acid or a mixture thereof having 6 to 24 carbon atoms can be used.

Examples of urea thickeners include urea compounds, urea / urethane compounds, urethane compounds, and the like. More specifically, examples include diurea compounds, triurea compounds, tetraurea compounds, polyurea compounds (excluding diurea compounds, triurea compounds, and tetraurea compounds), urea / urethane compounds, and diurethane compounds. Among these, at least one urea-based thickener selected from diurea compounds, urea / urethane compounds, and diurethane compounds can be preferably used. A preferred example of the urea compound can be represented by the following general formula (2). The compound group represented by the following general formula (3) includes diurea compounds, urea-urethane compounds, and diurethane compounds.

B ^1- (C═O) (NH) —R ³ — (NH) (C═O) —B ² (3)

In the general formula (3), R ³ represents a divalent organic group, preferably a C 6-20 divalent hydrocarbon group (including an aromatic group). B ¹ and B ² may be the same or different and each represents a group represented by —NHR ⁴ , —NR ⁵ R ⁶ or —OR ⁷ . R ⁴ , R ⁵ , R ⁶ and R ⁷ may be the same or different and each represents a monovalent organic group, which may be aliphatic, alicyclic or aromatic, or a mixture thereof. Preferably, it represents a monovalent hydrocarbon group having 6 to 20 carbon atoms.

The content of the thickener is preferably 2 to 40% by weight based on the total amount of the composition. When the content of the thickener is less than 2% by mass, the effect of adding the thickener becomes insufficient, and it becomes difficult to make the composition sufficiently grease (semi-solid). On the other hand, if the content of the thickener exceeds 40% by mass, the grease composition may become excessively hard and it may be difficult to obtain sufficient lubrication performance. From the same viewpoint, the content of the thickener is more preferably 3% by mass or more, further preferably 4% by mass or more, more preferably 35% by mass or less, and further preferably 25% by mass or less.

[Aliphatic amide compound]
Further, the aliphatic amide compound that can be blended includes a monoamide having one amide group (—NH—CO—), a bisamide having two, a triamide having three. The monoamide may be either a monoamine acid amide or a monoacid acid amide, and a bisamide, a diamine acid amide, or a diacid acid amide.
The amide compound preferably used is one having a melting point of 40 to 180 ° C., particularly preferably 80 to 180 ° C., more preferably 100 to 170 ° C., and a molecular weight of 242 to 932, particularly preferably 298 to 876.
Monoamide, bisamide, and triamide are represented by the following general formula (4), general formulas (5) and (6), and general formula (7), respectively.

R ¹¹ —CO—NH—R ¹² (4)
R ¹¹ —CO—NH—A ¹ —NH—CO—R ¹² (5)
R ¹¹ —NH—CO—A ¹ —CO—NH—R ¹² (6)
R ¹¹ -M-A ¹ -CH (A ² -M-R ¹³ ) -A ³ -M-R ¹² (7)

In the general formulas (4) to (7), R ¹¹ , R ¹² and R ¹³ are each independently an aliphatic hydrocarbon group having 5 to 25 carbon atoms. In the case of the general formula (4), the case where R ¹² is hydrogen is also included. A ¹ , A ² , and A ³ are each independently an aliphatic hydrocarbon group having 1 to 10 carbon atoms, an alicyclic hydrocarbon group, an aromatic hydrocarbon group, or a combination of these carbon numbers 1 to 10 divalent hydrocarbon groups, M is an amide group.
In the case of the monoamide of the general formula (4), R ¹² is preferably hydrogen or a saturated or unsaturated aliphatic hydrocarbon group having 10 to 20 carbon atoms. Further, in the case of the diamine acid amide of the general formula (5), it is preferable that A ¹ is a divalent saturated chain hydrocarbon group having 1 to 4 carbon atoms. Furthermore, in the formulas (5) and (6), in the hydrocarbon group represented by R ¹¹ , R ¹² , or A ¹ , part of hydrogen may be substituted with a hydroxyl group (—OH).

Specific examples of monoamides include saturated fatty acid amides such as lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, unsaturated fatty acid amides such as oleic acid amide and erucic acid amide, and Examples thereof include substituted amides with saturated or unsaturated long-chain fatty acids and long-chain amines such as stearyl stearamide, oleyl oleate amide, oleyl stearate amide, stearyl oleate amide and the like.

Specific examples of the acid amide of the diamine represented by the formula (5) include ethylene bis stearic acid amide, ethylene bis isostearic acid amide, ethylene bis oleic acid amide, methylene bis lauric acid amide, hexamethylene bis oleic acid amide. And hexamethylene bishydroxystearic acid amide. Specific examples of the diacid bisamide represented by the formula (6) include N, N′-bisstearyl sebacic acid amide.

There are many triamides represented by the formula (7), and specific examples of compounds that can be suitably used in the present invention include N-acylamino acid diamide compounds. The N-acyl group of this compound is a linear or branched saturated or unsaturated aliphatic acyl group or aromatic acyl group having 1 to 30 carbon atoms, particularly a caproyl group, a capryloyl group, a lauroyl group, a myristoyl group, Preferred are those comprising a stearoyl group, and preferred amino acids are those comprising aspartic acid and glutamic acid, and the amine of the amide group is a linear or branched saturated or unsaturated aliphatic amine having 1 to 30 carbon atoms, In particular, butylamine, octylamine, laurylamine, isostearylamine, stearylamine and the like are preferable. In particular, N-lauroyl-L-glutamic acid-α, γ-di-n-butylamide is preferred as a specific compound.

The above amide compounds may be used alone or in combination of two or more. The amide content is preferably 0.1 to 50% by mass, and preferably 3 to 35% by mass, based on the total amount of the lubricant composition.

[Other additives]
In addition to the above components, the lubricant composition of the present invention is generally used in lubricating oils and greases as necessary, for example, detergents, dispersants, antiwear agents, viscosity index improvers, antioxidants. An agent, extreme pressure agent, rust inhibitor, corrosion inhibitor and the like can be added as appropriate.
Additive components other than the above are preferably 20% by mass or less, particularly preferably 10% by mass or less, based on the total amount of the lubricant composition.

[Resin lubrication method]
The lubricant composition of the present invention is used for resin lubrication. The resin may be a natural resin or a synthetic resin, but general-purpose plastics (polyethylene, polystyrene, polypropylene, polyvinyl chloride, etc.) and engineering plastics of synthetic resins are good, and engineer plastics are particularly preferable in terms of heat resistance and mechanical strength. , Polyamide resins, polyacetal resins, polycarbonate resins, polysulfone resins, polyphenylene sulfide resins, polyamide imide resins, polyether ether ketone resins, phenol resins, polyester resins, epoxy resins and the like, and in particular, polyamide resins, It is preferably used for lubricating a polyoxymethylene resin. In this lubrication, if at least one component is a resin, the other component may be a metal, ceramic, or the like.
Applications using such lubrication methods include transport machinery such as automobiles, railways and aircraft, industrial machinery such as machine tools, home appliances such as washing machines, refrigerators and vacuum cleaners, and precision machinery such as watches and cameras. There are bearings, gears, sliding surfaces, belts, joints, cams and the like containing resin materials used in these machines. In particular, it is useful for improving the wear resistance of gears (spur gears, helical gears, screw gears, hypoid gears, worm gears, wheel gears, etc.) that become a high surface pressure sliding environment.

Examples and Comparative Examples were prepared and evaluated using the following components.
〔component〕
1. Lubricating base oil (1) PAO: Poly-α-olefin (Durasyn168 from INEOS)
Kinematic viscosity at 40 ° C .; 46 mm ² / s, density at 15 ° C .: 0.83 g / cm ³ , viscosity index; 135
Pour point: -60 ° C or lower, flash point: 250 ° C
(2) Mineral oil: Lubricating oil base oil obtained by solvent purification of distillate obtained by distillation of atmospheric distillation residue under reduced pressure Kinematic viscosity at 40 ° C; 46 mm ² / s, density at 15 ° C; 0.87 g / cm ³ , Viscosity index; 100
Pour point: -10 ° C, flash point: 230 ° C

2. Additive: Carboxylic acid derivative N-oleyl sarcosine For comparison, oleic acid, oleyl alcohol, oleylamine, and methyl oleate were added.

3. Thickener (1) Lithium soap: Lithium stearate (2) Complex lithium soap: Lithium salt of carboxylic acid mixed with stearic acid and azelaic acid (3) Aliphatic diurea: Fat consisting of octadecylamine and methylene difernyl diisocyanate (4) Alicyclic diurea: alicyclic diurea composed of cyclohexylamine and methylene difernyl diisocyanate (5) Aromatic diurea: aromatic diurea composed of p-toluidine and methylene difernyl diisocyanate Aliphatic amide: ethylenebisstearic acid amide

[Grease preparation method]
In the lubricating base oil, lithium soap grease and complex lithium soap grease dehydrated and saponified each fatty acid and lithium hydroxide, and urea grease reacted each amine with methylene difernyl diisocyanate. Ingredients were blended. Thereafter, pressure dispersion treatment was performed with a roller (three rolls) to prepare a grease.
[Method for preparing lubricating oil]
Each component was put in a container with the blending amounts shown in Tables 3 and 4 and stirred to prepare a lubricating oil. In addition, a compounding quantity is shown by the mass% with respect to the lubricant (grease or lubricating oil) whole quantity. The content of the base oil is the remainder of certain components such as thickeners.

〔Evaluation test〕
An evaluation test was conducted with a ball-disk reciprocating friction tester. The test load was 21.6 N, the sliding speed was 10 mm / s, the amplitude was 20 mm, 1 g of lubricant was applied to the disk, and the friction coefficient after 20 minutes was measured at room temperature. Steel (SUJ-2), polyamide resin (PA66), and polyoxymethylene resin (POM) are used as the material for the balls and disks, and the ball diameter is 1/4 inch. Tables 1, 2, 3, and 4 show the ball and disk materials and the friction coefficient measurement results for each lubricant evaluation. It can be seen that the friction coefficient is reduced when the carboxylic acid derivative of the present invention is contained.
The stick-slip resistance was evaluated according to the following criteria based on the ratio of the static friction coefficient and the dynamic friction coefficient per reciprocation. Note that stick slip is more likely to occur as the difference between the static friction coefficient and the dynamic friction coefficient increases.
Excellent stick-slip resistance (Static friction coefficient / Dynamic friction coefficient = 0.9 to 1.1)
X Inferior stick-slip resistance (Static friction coefficient / Dynamic friction coefficient = less than 0.9 or greater than 1.1)
It was confirmed that the lubricant containing the carboxylic acid derivative had a small difference between the coefficient of static friction and the coefficient of dynamic friction, and was also effective in stick-slip resistance.

The lubricant composition of the present invention can reduce the coefficient of friction in resin lubrication, has excellent wear resistance, excellent stick-slip resistance, and can be highly reliable over a long period of time. Resin materials used in transportation machinery such as automobiles, railways and aircraft, industrial machinery such as machine tools, household appliances such as washing machines, refrigerators and vacuum cleaners, and precision machinery such as watches and cameras. Can be used as a lubricant for sliding parts such as bearings, gears, sliding surfaces, belts, joints, and cams. In addition, the lubrication method of the present invention can reduce the coefficient of friction in resin lubrication, has excellent wear resistance, excellent stick-slip resistance, and enables high reliability over a long period of time. This is useful for sliding parts.

Claims

Lubricant base oil and a resin lubricant composition containing an amide bond and a carboxylic acid derivative containing a carboxyl group in the same compound.
The lubricant composition for a resin according to claim 1, wherein the carboxylic acid derivative is represented by the following general formula (1) or general formula (2).
R 1- (C═O) — (N—R 2 ) —A— (C═O) —OH (1)
R 1- (N—R 2 ) — (C═O) —A— (C═O) —OH (2)
(In the above formula, R 1 is a monovalent hydrocarbon group, R 2 is hydrogen or a monovalent hydrocarbon group, A is a divalent hydrocarbon group, and these hydrocarbon groups include (It may contain an oxygen group.)
In General Formula (1) or General Formula (2), R 1 is an alkenyl group having 4 to 24 carbon atoms, R 2 is hydrogen or an alkyl group having 1 to 8 carbon atoms, and A is 1 to The lubricant composition for a resin according to claim 2, which is an alkylene group of 8.
The lubricant composition for a resin according to claim 2, wherein, in the general formula (1) or the general formula (2), R 1 is a hydrocarbon group containing an ester bond having 4 to 24 carbon atoms.
The resin lubricant composition according to any one of claims 1 to 4, which is used for lubricating a resin containing at least one of a polyamide resin and a polyoxymethylene resin.
The resin lubricant composition according to any one of claims 1 to 5, wherein the lubricating base oil is a hydrocarbon oil.
The resin lubricant composition according to any one of claims 1 to 6, which further contains a thickener and is a grease.
The resin lubricant composition according to any one of claims 1 to 7, wherein the total content of the carboxylic acid derivative is 0.02 to 20 mass% based on the total amount of the lubricant composition.
Lubricating base oil and a resin lubricating method in which a lubricant composition containing an amide bond and a carboxylic acid derivative containing a carboxyl group in the same compound is interposed on the surface of the resin.