JPH0714896B2 - Carboxylic acid perfluoroalkyl ester derivative and lubricant containing carboxylic acid perfluoroalkyl ester derivative - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a novel carboxylic acid perfluoroalkyl ester derivative which exhibits a good lubricating action even in a low temperature range and is useful as a lubricant. The present invention relates to a lubricant containing a carboxylic acid perfluoroalkyl ester derivative.

[Outline of Invention]

The present invention is represented by the general formula RCH ₂ COOCH ₂ C _j F _{2j + 1} (wherein R is a saturated or unsaturated aliphatic hydrocarbon group having 3 to 24 carbon atoms, and j is an integer of 4 or more). It is intended to provide a novel carboxylic acid perfluoroalkyl ester derivative that exhibits excellent lubricity under all conditions of use, and further to provide a lubricant containing this carboxylic acid perfluoroalkyl ester derivative. .

[Conventional technology]

As lubricants, various compounds such as liquid lubricants represented by higher fatty acids and their esters and solid lubricants represented by molybdenum disulfide have been known, and their applications are expanding.

For example, in a ferromagnetic metal thin film type magnetic recording medium in which a ferromagnetic metal material is deposited on a polymer film by a method such as vapor deposition and used as a magnetic layer, the smoothness of the magnetic layer surface is extremely good. Since there is a large contact area, the adhesion phenomenon (so-called sticking) is likely to occur and the friction coefficient becomes large, there are many drawbacks in durability and runnability, so use of various lubricants to improve it. Is being considered.

Lubricants used for such special applications are required to have strict characteristics depending on the applications, and it is difficult to sufficiently cope with them with known lubricants.

Taking the above ferromagnetic metal thin film type magnetic recording medium as an example,
The lubricant to be used is i) excellent in low temperature characteristics so as to ensure a predetermined lubrication effect even in use in cold regions, ii) spacing loss with the magnetic head becomes a problem, so it is applied very thinly It is required that it can be done, and in that case, sufficient lubricity is exhibited, and iii) that the effect lasts for a long time just by applying it on the surface. On the other hand, many liquid lubricants such as fatty acids and their esters solidify or freeze at a low temperature such as 0 to -5 ° C, and the lubricating effect cannot be sufficiently exhibited. In addition, the solid lubricant is
For example, it is not practical as a lubricant for a tape-shaped medium (magnetic tape).

[Problems to be solved by the invention]

Therefore, the present invention aims at the development of a novel compound which maintains the adhesiveness and lubricity under any use conditions, and has a long-lasting lubrication effect by simply applying it to the surface. It is an object of the present invention to provide a lubricant suitable for use in magnetic metal thin film type magnetic recording media and the like.

[Means for solving problems]

The present inventors, as a result of repeated intensive studies with those that do not achieve the above objects, found that certain carboxylic acid perfluoroalkyl ester derivatives first synthesized by the present inventors are suitable for this purpose, The present invention has been completed based on this finding.

That is, the present invention provides a compound represented by the general formula RCH ₂ COOCH ₂ C _j F _{2j + 1} (I) (wherein R is a saturated or unsaturated aliphatic hydrocarbon group having 3 to 24 carbon atoms, and j is an integer of 4 or more). The present invention provides a carboxylic acid perfluoroalkyl ester derivative represented by the formula (1), and a lubricant containing the carboxylic acid perfluoroalkyl ester derivative.

R in the general formula (I) is an aliphatic hydrocarbon group, which may be linear or branched, and may further contain a double bond. Therefore, when the aliphatic hydrocarbon group moiety RCH ₂ − in the formula is represented by C _n H _m −,
m ≦ 2n + 1. Here, n and m are not particularly limited, but selected from 4 ≦ n ≦ 25.

On the other hand, the carbon number j in the perfluoroalkyl group C _j F _{2j + 1} − may be 4 or more, but is preferably 6 or more.

The carboxylic acid perfluoroalkyl ester derivatives of the present invention are all novel compounds that have not been published in the literature and are represented by the general formula C _n H _m COCl (III) (wherein n and m are integers). And an fluorinated alcohol represented by the general formula C _j F _{2j + 1} CH ₂ OH (III) (wherein j is an integer of 4 or more) in substantially equimolar amounts Can be synthesized. The reaction formula is as follows.

The reaction between the compound of general formula (II) and the compound of general formula (III) conveniently proceeds in the presence of a base such as triethylamine in a solvent such as chloroform. The reaction temperature is not necessarily constant depending on the type of raw material, the type of solvent, and other conditions, but normally it proceeds easily by stirring at room temperature. The resulting carboxylic acid perfluoroalkyl ester derivative can be easily isolated from the reaction mixture by vacuum distillation.

The acid chloride represented by the general formula (II) can be easily synthesized by chlorinating a commercially available aliphatic carboxylic acid with phosphorus pentachloride PCl ₅ . In particular, the carbon number n of the aliphatic carboxylic acid
Those with a small value can be synthesized by chlorination with thionyl chloride SOCl ₂ . The reaction formula is as follows.

Here, usable aliphatic carboxylic acids include butanoic acid, caprylic acid, and corresponding to the above-mentioned aliphatic hydrocarbon group R.
Examples thereof include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, elaidic acid, linoleic acid and linolenic acid.

Fluorine-containing alcohol C _j F represented by the above general formula (III)
_{For 2j + 1} CH ₂ OH, the perfluorocarboxylic acid obtained by the Simmons method, etc. was converted to dimethylformamide (DM
F) After chlorination in the presence, it can be easily synthesized by reducing with a reducing agent. The reaction formula is as follows.

The carboxylic acid perfluoroalkyl ester synthesized as described above may be used alone as a lubricant, or may be used by mixing with a conventionally known lubricant to further expand the temperature range for use. .

As the lubricant used, a fatty acid or a metal salt thereof,
Fatty acid amide, fatty acid ester, aliphatic alcohol or alkoxide thereof, aliphatic amine, polyhydric alcohol,
Sorbitan ester, mannitan ester, sulfurized fatty acid, aliphatic mercaptan, modified silicone oil, perfluoroalkylethylene oxide, perfluoropolyethers, higher alkyl sulfonic acid or its metal salt, perfluoroalkyl sulfonic acid or its ammonium salt or its Examples thereof include metal salts, perfluoroalkylcarboxylic acids or metal salts thereof, perfluoroalkylcarboxylic acid esters and the like.

In particular, a perfluoroalkylcarboxylic acid ester represented by the general formula C _n F _{2n + 1} COOR (wherein n represents an integer of 6 to 10 and R represents a hydrocarbon group having 1 to 25 carbon atoms). Also, since it has good low-temperature characteristics, it is suitable for use in combination with the above-mentioned perfluoroalkyl carboxylic acid ester.

Further, an extreme pressure agent may be used in combination at a weight ratio of about 30:70 to 70:30 in order to cope with more severe use conditions and to maintain the lubricating effect.

The above extreme pressure agent reacts with the metal surface by frictional heat generated when a metal contact is partially generated in the boundary lubrication region, and forms a reaction product film to prevent friction and wear. Therefore, phosphorus-based extreme pressure agents, sulfur-based extreme pressure agents, halogen-based extreme pressure agents, organometallic extreme pressure agents, composite type extreme pressure agents and the like are known.

Specifically, examples of the phosphorus-based extreme pressure agent include tributyl phosphate, trioctyl phosphate, tri-2-ethylhexyl phosphate, trilauryl phosphate, trioleyl phosphate, dibutyl phosphate, dioctyl phosphate, di-2-ethylhexyl phosphate. , Phosphates such as dilauryl phosphate, dioleyl phosphate, tributyl phosphite, trioctyl phosphite, tri-2-ethylhexyl phosphite, trilauryl phosphite, trioleyl phosphite, dibutyl phosphite, dioctyl phosphite, dioctyl phosphite, dioctyl phosphite 2-Ethylhexyl phosphite, dilauryl phosphite, dioleyl phosphite and other phosphites, dibutyl phosphate butylamine salts, dibutyl Phosphate octyl amine salt, dibutyl phosphate Tosute allyl amine salt, dioctyl phosphate butyl amine salt, dioctyl phosphate octyl amine salt, dioctyl phosphate lauryl amine salt, dioctyl phosphate Tosute allylamine hydrochloride,
Di-2-ethylhexyl phosphate butylamine salt,
Di-2-ethylhexylphosphate octylamine salt, di-2-ethylhexylphosphate laurylamine salt, di-2-ethylhexylphosphate stearylamine salt, dilaurylphosphate butylamine salt, dilaurylphosphate octylamine salt, dilaurylphosphate laurylamine salt, Examples thereof include phosphate ester amine salts such as dilauryl phosphate stearyl amine salt, dioleyl phosphate butyl amine salt, dioleyl phosphate octyl amine salt, dioleyl phosphate lauryl amine salt, and dioleyl phosphate stearyl amine salt.

Examples of the sulfur-based extreme pressure agent include sulfurized whale oil, mineral oil having an unsaturated bond such as sulfurized dipentene, sulfurized fats and oils produced by adding sulfur to fats and oils and fatty acids, and heating, dibenzyl disulfide, and disulfide. Diphenyl, di-disulfide
t-butyl, di-sec-butyl disulfide, di-n-disulfide
Disulfides such as butyl, di-t-octyl disulfide, diethyl disulfide, benzyl sulfide, diphenyl sulfide, divinyl sulfide, dimethyl sulfide, diethyl sulfide, di-t sulfide
-Butyl, di-sec-butyl sulfide, mono-sulfides such as di-n-butyl sulfide, dimethyl trisulfide, disulfide tri-
Polysulfides such as t-butyl, polysulfide di-t-nonyl, olefin polysulfide, and general formula Or (However, in the formula, R represents a hydrocarbon group.), Thiocarbonates and elemental sulfur.

Examples of the halogen-based extreme pressure agent include bromine compounds such as allyl bromide, octadecyl bromide, cyclohexyl bromide, stearyl bromide, and benzyl heavy oxide, benzyl iodide, allyl iodide, butyl iodide, octadecyl iodide, and iodine. Iodine compounds such as cyclohexyl chloride, hexachloroethane, monochloroethane, chlorinated paraffin, chlorinated diphenyl,
Chlorinated compounds such as chlorinated fats and oils, methyltrichlorostearate, pentachloropentadienoic acid, esters of hexachloronaphtheric acid compounds, and imide derivatives of hexachloronaphthenic acid compounds can be mentioned.

Examples of the organometallic extreme pressure agent include zinc diisobutyldithiophosphate, zinc isobutylpentyldithiophosphate, isopropyl-1-methylbutyldithiophosphate, zinc isobutylnonylphenyldithiophosphate, isobutylheptylphenyldithiophosphate, diheptylphenyldithiophosphate, dipentylphenyldithiophosphate. Zinc nonylphenyldithiophosphate, thiophosphates such as molybdenum dithiophosphate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyldithiocarbamate, zinc ethylphenyldithiocarbamate, zinc dibenzyldithiocarbamate, zinc dimethyldithiocarbamate, dimethyldithiocarbamate Copper, iron dimethyldithiocarbamate,
Thiocarbamate salts such as selenium diethyldithiocarbamate and silver diethyldithiocarbamate, molybdenum,
Metal alkyl dithiocarbamates such as antimony,
Etc.

Examples of the complex-type extreme pressure agent include dialkylthiophosphate amines such as di-2-ethylhexylthiophosphate amine, propyl chloride chloride, propyl bromide,
Alkyl halide phosphates represented by propyl iodide phosphate, butyl chloride phosphate, butyl bromide phosphate, iodobutyl phosphate, etc., chloronaphthazanate, etc. (However, in each general formula, R represents a hydrogen atom or an alkyl group, an alkenyl group, or an aryl group.) The thiophosphates represented by the general formula (However, in the formula, R represents a hydrogen atom or an alkyl group, an alkenyl group, or an aryl group.) The thiophosphites and the like are highly effective.

The above extreme pressure agents may be used alone, but it is also possible to use a mixture of two or more kinds.

Alternatively, in addition to the above-mentioned lubricant and extreme pressure agent, a rust preventive agent may be used in combination if necessary. Any conventionally known rust preventive can be used as the rust preventive.

As a method for attaching the lubricant containing these carboxylic acid perfluoroalkyl ester derivatives, a solution obtained by dissolving the lubricant in a solvent is applied or sprayed, or conversely, it is dipped in the solution and dried. do it.

[Action]

The carboxylic acid perfluoroalkyl ester derivative exhibits a good lubricating action to reduce the friction coefficient. Further, this lubricating action is not impaired even at low temperatures.

Therefore, the lubricant containing the carboxylic acid perfluoroalkyl ester derivative also exhibits good lubricity and low temperature characteristics.

[Examples] Hereinafter, specific examples of the present invention will be described, but the present invention is not limited to these examples.

First, a carboxylic acid perfluoroalkyl ester derivative was synthesized according to the following synthesis example.

Synthesis Example 1. Commercially available oleic acid was chlorinated with phosphorus pentachloride (PCl ₅ ) to obtain oleic acid chloride.

On the other hand, pentadecafluorooctanoic acid was chlorinated with thionyl chloride (SOCl ₂ ) using dimethylformamide (DMF) as a catalyst and then reduced with lithium aluminum hydride to synthesize pentadecafluoro-1-octanol.

Next, the pentadecafluoro-1-octanol was dissolved in chloroform together with triethylamine, and the oleic acid chloride synthesized above was added dropwise over 30 minutes under ice cooling. After completion of the dropping, the mixture was stirred overnight at room temperature. After washing this with water, 5% dilute hydrochloric acid, NaHCO ₃ aqueous solution, and water in this order,
It was purified by distillation under reduced pressure. The obtained product was designated as Compound 1.

As in the following synthesis examples, the product was confirmed by infrared spectroscopy (IR) and mass spectrometry (MASS).
That is, the absorption of CF bonds characteristic over the 1360～1100Cm ^-1 is observed, the absorption of the esters of C = O is observed in 1760 cm ^-1, absorption by stretching vibration of CH to 3020cm ^-1 and 2930 cm ^-1 observed It was confirmed as oleic acid pentadecafluorooctyl ester. The presence of 664 molecular ion peak M ^{+ in} the mass spectrum by mass spectrometry also supports this structure. The mass spectrometry was performed using a mass spectrometer DX303 manufactured by JEOL Ltd., and was measured after confirming that it was a single component by a gas chromatograph.

The mass spectrometry spectrum and infrared absorption spectrum of the obtained product are shown in FIG. 1 and FIG. 2, respectively.

Synthesis Example 2. Commercially available linoleic acid was chlorinated with thionyl chloride (SOCl ₂ ) to synthesize linoleic acid chloride, which was cooled in a chloroform solution of pentadecafluoro-1-octanol and triethylamine in the same manner as in Synthesis Example 1. Dropped down. Then, the same treatment as in Synthesis Example 1 was performed, followed by vacuum distillation for purification. The obtained product was designated as compound 2.

Synthesis Example 3. Commercially available linolenic acid was chlorinated with thionyl chloride (SOCl ₂ ) to synthesize linolenic acid chloride, which was cooled with ice in a chloroform solution of pentadecafluoro-1-octanol and triethylamine in the same manner as in Synthesis Example 1. Dropped down. Then, the same treatment as in Synthesis Example 1 was performed, followed by vacuum distillation for purification. The product thus obtained was designated as Compound 3.

Synthetic Example 4. Commercially available myristic acid was chlorinated with phosphorus pentachloride (PCl ₅ ) to synthesize myristic acid chloride, which was treated with pentadecafluoro-1-octanol and triethylamine in a chloroform solution in the same manner as in Synthetic Example 1. It was added dropwise under cooling. Then, the same treatment as in Synthesis Example 1 was performed, followed by vacuum distillation for purification. The obtained product was designated as compound 4.

Synthetic example 5. Commercially available palmitic acid was chlorinated with phosphorus pentachloride (PCl ₅ ) to synthesize palmitic acid chloride, which was then cooled in a chloroform solution of pentadecafluoro-1-octanol and triethylamine in the same manner as in Synthetic example 1. It was added dropwise under cooling. Then, the same treatment as in Synthesis Example 1 was performed, followed by vacuum distillation for purification. The obtained product was named compound 5.

Synthesis example 6. Commercially available myristic acid is chlorinated with phosphorus pentachloride (PCl ₅ ),
Obtained myristic acid chloride.

On the other hand, nonadecafluorodecanoic acid was chlorinated with thionyl chloride (SOCl ₂ ) using dimethylformamide (DMF) as a catalyst and then reduced with lithium aluminum hydride to synthesize nonadecafluoro-1-decanol.

Next, the nonadecafluoro-1-decanol was dissolved in chloroform together with triethylamine, and the myristic acid chloride synthesized above was added dropwise over 30 minutes under ice cooling. After completion of the dropping, the mixture was stirred overnight at room temperature. This in water,
After washing with 5% dilute hydrochloric acid, an aqueous solution of NaHCO ₃ , and water in this order, distillation was performed under reduced pressure for purification. The obtained product was designated as compound 6.

Synthesis Example 7. Commercially available linolenic acid was chlorinated with thionyl chloride (SOCl ₂ ) to synthesize linolenic acid chloride, which was cooled with ice in a chloroform solution of nonadecafluoro-1-decanol and triethylamine in the same manner as in Synthesis Example 6. Dropped down. Then, the same treatment as in Synthesis Example 6 was performed, followed by distillation under reduced pressure for purification. The product thus obtained was designated as Compound 7.

Synthesis Example 8. Commercially available butanoic acid chloride was added dropwise to a chloroform solution of nonadecafluoro-1-decanol and triethylamine under ice cooling as in Synthesis Example 6. Then, the same treatment as in Synthesis Example 6 was performed, followed by distillation under reduced pressure for purification. The obtained product was named compound 8.

The boiling point and yield of the compound obtained in each of the above-mentioned synthesis examples are
Shown in the table.

Next, the obtained carboxylic acid perfluoroalkyl ester derivative was applied to a lubricant of a ferromagnetic metal thin film type magnetic recording medium, and its lubricating effect was investigated.

Application example 1. Co was deposited on a polyethylene terephthalate film with a thickness of 14 μm by oblique deposition to form a ferromagnetic metal thin film with a thickness of 1000 Å.

Next, a solution prepared by dissolving 0.48 g of carboxylic acid perfluoroalkyl ester (Compound 1 synthesized in the previous synthesis example) shown in Table 1 in 800 g of Freon was applied to the surface of this ferromagnetic metal thin film, and the width was 8 mm. It cut and produced the sample tape.

Application Example 2 to Application Example 8 A sample tape was prepared in the same manner as in Application Example 1 except that the compounds 2 to 8 shown in Table 1 above were used as the carboxylic acid perfluoroalkyl ester.

With respect to each of the prepared sample tapes, the dynamic friction coefficient and the shuttle durability under the conditions of a temperature of 25 ° C., a relative humidity (RH) of 50%, and −5 ° C. were measured. This dynamic friction coefficient is
This is a test using a guide pin made of stainless steel (SUS304) with a constant tension and a speed of 5 mm / sec. Further, the shuttle durability was evaluated by the number of shuttles until the output decreased by -3 dB after the shuttle traveled for 2 minutes each time. For still durability, the decay time of the output up to −3 dB in the paused state was evaluated. In addition, as a comparative example, a blank tape on which no lubricant was applied was also measured. The results are shown in Table 2.

As is clear from this table, in each application example, the dynamic friction coefficient is small under each condition of room temperature and low temperature, the running is very stable, and the tape surface is not damaged even after 100 reciprocating runs. There wasn't. Also, the durability is extremely good, 150
The output did not decrease by -3 dB even after the shuttle shuttle was run. On the other hand, in the tape of the comparative example having no lubricant layer, the coefficient of friction increased as the number of times of reciprocation was increased, the operation was unstable, the tape was worn, and the durability was poor.

〔The invention's effect〕

As is clear from the above description, the carboxylic acid perfluoroalkyl ester derivative of the present invention exhibits extremely excellent lubricity, and its lubricity is maintained even at low temperatures.

Furthermore, the carboxylic acid perfluoroalkyl ester derivative of the present invention is easy to synthesize and handle.

Therefore, if this carboxylic acid perfluoroalkyl ester derivative is used alone or in combination with other components to form a lubricant, it is suitable not only for various machines but also for special applications such as ferromagnetic metal thin film type magnetic recording media. Is.

The lubricant of the present invention exerts a good lubricating effect for a long time only by being applied to the surface, and the lubricating effect does not deteriorate even when it is used in a low temperature range.

[Brief description of drawings]

FIG. 1 is a mass spectrometric spectrum of oleic acid pentadecafluorooctyl ester synthesized in the synthesis example of the present invention, and FIG. 2 is its infrared absorption spectrum.

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Claims (2)

[Claims] 1. A compound represented by the general formula RCH ₂ COOCH ₂ C _j F _{2j + 1} (wherein R is a saturated or unsaturated aliphatic hydrocarbon group having 3 to 24 carbon atoms, and j is an integer of 4 or more). Carboxylic acid perfluoroalkyl ester derivative represented. 2. The general formula RCH ₂ COOCH ₂ C _j F _{2j + 1} (wherein R is a saturated or unsaturated aliphatic hydrocarbon group having 3 to 24 carbon atoms, and j is an integer of 4 or more). A lubricant containing a carboxylic acid perfluoroalkyl ester derivative represented.