JPH03167158A - Fluoro group-containing alkyl ester derivative of aliphatic carboxylic acid and lubricant containing the same - Google Patents

Abstract

NEW MATERIAL:Fluoro group-containing alkyl ester derivative of aliphatic carboxylic acid expressed by formula I (R is aliphatic hydrocarbon group; p is integer of >=4; m is integer satisfying 2p-4<=m<=2p; n is integer satisfying 1<=n<=5; m+n=2p+1). USE:It exhibits excellent lubricating action at low temperature and good compatibility with common organic substance such as aliphatic hydrocarbon and is useful as a lubricant for magnetic recording medium having ferromagnetic metal thin film. PREPARATION:The compound of formula I can be produced by reacting an aliphatic carboxylic acid with thionyl chloride and reacting the resultant acid chloride of formula II (x and y are integer) with nearly equimolar amount of a fluoro group-containing alcohol of formula III in a solvent such as tetrahydrofuran in the presence of a base such as triethylamine. The compound of formula III is e.g. 1,1,8-trihydrotetradecafluorooctanol-1.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an aliphatic carboxylic acid fluoro group-containing alkyl ester derivative, and a lubricant containing this aliphatic carboxylic acid fluoro group-containing alkyl ester derivative. , an aliphatic carboxylic acid fluoro group-containing aliphatic carboxylic acid that exhibits good lubrication even at low temperatures, has good compatibility with general organic substances such as aliphatic hydrocarbons, and is suitable for use in ferromagnetic metal thin film type magnetic recording media. The present invention relates to an alkyl ester derivative and a lubricant containing the aliphatic carboxylic acid fluoro group-containing alkyl ester derivative.

[Conventional technology]

In general, lubricants used in ferromagnetic metal thin film magnetic recording media are extremely thin to ensure a certain lubrication effect, especially when used in cold regions, and to avoid spacing loss with the magnetic head. It must be able to be applied, exhibit sufficient lubricity, and maintain its effect for a long time even when applied only to the back surface.

However, conventional liquid lubricants such as higher fatty acids and their esters often solidify or freeze at low temperatures such as 0 to -5°C, making it impossible to fully demonstrate their lubricating effects. Solid lubricants such as molybdenum sulfide are not practical as lubricants for magnetic tapes and the like.

In order to solve these problems, various lubricants have been researched and developed, and for example, lubricants containing carboxylic acid perfluoroalkyl ester derivatives and carboxylic acid perfluoroalkyl ester mN forms have been proposed. (JP-A-62-161744) [Problems to be Solved by the Invention] However, since this type of carboxylic acid perfluoroalkyl ester derivative contains a perfluoroalkyl group,
When used in a ferromagnetic metal thin film type magnetic recording medium, etc., it has poor compatibility with the magnetic layer and back coat layer, and may aggregate on the magnetic head during running, causing dropout.

[Means to solve the problem]

This invention was made as a result of various studies in view of the current situation, and provides a lubricant containing an aliphatic carboxylic acid fluoro group-containing alkyl ester derivative containing a fluoro group, and an aliphatic carboxylic acid fluoro group-containing alkyl ester derivative, By using it in ferromagnetic metal thin film type magnetic recording media, etc., it suppresses the decline in the lubricating effect in low temperature ranges and the occurrence of dropouts due to agglomeration, which conventional lubricants have. The present invention provides a lubricant suitable for magnetic recording media.

The aliphatic carboxylic acid fluoro group-containing alkyl ester derivative in this invention is -i formula % formula % (however, R in the formula is an aliphatic hydrocarbon group, P is 4 or more (however, R in the formula is 2p-4 An integer of ≦m≦2p, n is 1≦n≦
It is an integer of 5, and m+n=2p+1. ) is an aliphatic carboxylic acid fluoro group-containing alkyl ester derivative represented by the following: Because it contains a fluoro group, it does not solidify or freeze even at low temperatures such as 0 to -5°C, and exhibits excellent lubricating effects at low temperatures. . In addition, since 1 to 5 perfluoroalkyl groups are substituted with hydryl groups, it is soluble in organic solvents such as aliphatic hydrocarbons, and has good adhesion to the pack coat layer surface of ferromagnetic metal thin film magnetic recording media. It has excellent properties and does not cause aggregation, so dropouts due to aggregation do not occur. Therefore, it is extremely suitable for use in ferromagnetic metal thin film type magnetic recording media.

R in the above general formula of such aliphatic carboxylic acid fluoro group-containing alkyl ester derivative is an aliphatic hydrocarbon group, which may be linear or branched, and may further contain a double bond. Therefore, when this aliphatic hydrocarbon group R is represented by C, H, -,
≦2y+1, and there is no particular restriction on χ and y, but they are usually selected from about y≦30.

Also, fluoro group-containing alkyl groups C, F, H.

The number of carbon atoms p in - may be 4 or more, but preferably 6 or more, and the number m of fluoro groups is 2p-4≦m
It is sufficient that ≦2p, but it is more preferable that 2p-1≦m≦2p. Furthermore, the relationship between the number m of fluoro groups and the number n of hydro groups is preferably m+n=2p+1.

The synthesis of such aliphatic carboxylic acid fluoro group-containing alkyl ester derivatives is carried out by the reaction of acid chloride and alcohol, which is the usual ester synthesis method.First, the aliphatic carboxylic acid is reacted with thionyl chloride to form the general formula An acid chloride represented by the formula % (where X and y in the formula are each an integer) is synthesized. This can be easily purified by vacuum distillation.

Then, convert this to the general formula % formula % (where p in the formula is 4 or more (however, R in the formula is an aliphatic hydrocarbon group, p is an integer of 4 or more, n is 2p-4≦m≦2p is an integer of m+n-2p+1).

If this is shown as a reaction formula, C, H, C0Cj! +CpF, H, CH20H-〉CX
It is expressed as H, CO0CHz CpF, Ha, and this reaction easily proceeds in the presence of a base such as triethylamine in a fg medium such as tetrahydrofuran or chloroform. The obtained aliphatic carboxylic acid fluoro group-containing alkyl group ester derivative can be easily purified by vacuum distillation. Usable aliphatic carboxylic acids include butanoic acid, caprylic acid, capric acid, Examples include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, linoleic acid, and linuric acid.

In addition, the fluoro group-containing alcohol represented by the above-mentioned general 2CpF,)lnCH,OH includes 1,1°8-trihydrotetradecafluorooctano-1.1.1,
2.2-tetrahydrotridecafluorooctano-1.1,1.10-trihydrooctadecafluorodecanol-1,1,1,2,2-tetrahydrohebutadecafluorodecanol-1, etc. It will be done.

The fluoro group-containing alkyl ester of aliphatic carboxylic acid synthesized in this manner may be used alone as a lubricant, but it may be used in combination with a conventionally known lubricant to further expand the temperature range of use. You can.

Lubricants used in combination include fatty acids or their metal salts,
Fatty acid amide, fatty acid ester, fatty alcohol or its alkoxide, fatty amine, polyhydric alcohol,
Sorbitan ester, manniratan ester, sulfurized fatty acid, aliphatic mercaptan, modified silicone oil, perfluoroalkyl ethylene oxide, perfluoropolyethers, higher alkyl sulfonic acid or its metal salt, ivy-fluoroalkyl sulfonic acid or its ammonium salt, or Metal salts thereof, perfluoroalkylcarboxylic acids, or metal salts thereof are preferably used, and perfluoropolyethers are particularly preferably used because they are effective in lowering the coefficient of friction.

In addition, in order to cope with more severe usage conditions and maintain a lubricating effect, the aliphatic carboxylic acid fluoro group-containing alkyl ester and the above-mentioned lubricant were mixed in a weight ratio of 30:1.
They may be blended at a blending ratio of ~70:30, and an extreme pressure agent may be further used in combination.

When this extreme pressure agent makes partial metal contact in the boundary lubrication area, it reacts with the metal surface due to the accompanying frictional heat, forming a reaction product film to prevent friction and wear. Among these, phosphorus-based extreme pressure agents, sulfur-based extreme pressure agents, halogen-based extreme pressure agents, organometallic-based extreme pressure agents, composite-based extreme pressure agents, etc. are known.

Specific examples of such extreme pressure agents include, for example, phosphorus-based extreme pressure agents such as tributyl phosphate, trioctyl phosphate, tri-2-ethylhexyl phosphate, trilauryl phosphate, trioleyl phosphate, dibutyl phosphate, and dioctyl phosphate. Phosphate, phosphoric acid esters such as di-2-ethylhexyl phosphate, dilauryl phosphate, dioleyl phosphate, tributyl phosphite, trioctyl phosphite, tri-2-ethylhexyl phosphite, trilauryl phosphite, trioleyl phosphite , dibutyl phosphite, dioctyl phosphite, G2
- Phosphite esters such as ethylhexyl phosphite, dilauryl phosphite, dioleyl phosphite, dibutyl phosphate butyl amine salt, dibutyl phosphate octyl amine salt, dibutyl phosphate stearyl amine salt, dioctyl phosphate butyl amine salt,
Dioctyl phosphate octylamine salt, dioctyl phosphate laurylamine salt, dioctyl phosphate stearylamine salt, di-2-ethylhexyl phosphate butylamine salt, di-2-ethylhexyl phosphate octylamine salt, di-2-ethylhexyl phosphate laurylamine salt, Di-2-ethylhexyl phosphate stearylamine salt, dilauryl phosphate butylamine salt, dilauryl phosphate octylamine salt, dilauryl phosphate laurylamine salt, dilauryl phosphate stearylamine salt, dioleyl phosphate butylamine salt, dioleyl phosphate octylamine salt, dio Examples include phosphoric acid ester amine salts such as leylphosphate laurylamine salt and dioleylphosphate stearylamine salt.

Sulfur-based extreme pressure agents include mineral oils with unsaturated bonds such as sulfurized whale oil and sulfurized dipentene, sulfurized oils and fats produced by adding sulfur to fats and oils and fatty acids, and heating them, dibenzyl disulfide, and disulfide. diphenyl, di-butyl disulfide, di-5ec-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-1 sulfide
Monosulfides such as -butyl, di-5ec-butyl sulfide, di-n-butyl sulfide, etc.1. Dimethyl trisulfide, di-t-butyl trisulfide, monononyl polysulfide, polysulfides such as olefin polysulfide, thiocarbonates represented by the general formula (wherein R represents a hydrocarbon group), and elements Examples include sulfur.

Furthermore, halogenated extreme pressure agents include bromine compounds such as allyl bromide, octadecyl bromide, cyclohexyl bromide, stearyl bromide, benzyl bromide, benzyl iodide, allyl iodide, butyl iodide, octadecyl iodide, Iodine compounds such as cyclohexyl iodide, hexachloroethane, monochloroethane, chlorinated paraffin, chlorinated diphenyl, chlorinated fats and oils, methyl trichlorostearate, pentachloropentadienoic acid, esters of hexachloronaphthenic acid compounds, hexachloronaphthenic acid compounds Examples include chlorine compounds such as imide derivatives of.

Examples of organometallic extreme pressure agents include zinc diisobutyldithiophosphate, zinc isobutylpentyldithiophosphate, isopropyl-1-methylbutyldithiophosphate, zinc isobutylnonylphenyldithiophosphate, isobutylhebutylphenyldithiophosphate, and diheptylphenyldithiophosphate. ,
Zinc dinonyl phenyl dithiophosphate, thiophosphates such as molybdenum dithiophosphate, zinc dimethyl dithiocarbamate, zinc diethyldithiocarbamate, zinc dibutyl dithiocarbamate, zinc ethyl phenyl dithiocarbamate, zinc dibenzyldithiocarbamate, zinc dimethyl dithiocarbamate, Examples include thiocarbamates such as copper dimethyldithiocarbamate, iron dimethyldithiocarbamate, selenium diethyldithiocarbamate, and silver diethyldithiocarbamate, and metal alkyldithiocarbamates such as molybdenum and antimony.

Examples of composite extreme pressure agents include dialkylthiophosphate amines such as di-2-ethylhexylthiophosphate amine, propyl chloride, propyl bromide, propyl iodide, butyl chloride, butyl bromide phosphate, and iodine. Highly effective examples include phosphoric acid esters of alkyl halides such as butyl phosphate, thiophosphates such as clonafsanthate, and thiophosphite M.

The above extreme pressure agents may be used alone, or two or more types may be used in combination, and in addition to these extreme pressure agents and lubricants, rust preventive agents may be used in combination as necessary. As the rust preventive agent, any conventionally known rust preventive agent can be used.

A method for attaching a lubricant containing an alkyl ester derivative containing an aliphatic carboxylic acid fluoro group to a ferromagnetic metal thin film type magnetic recording medium is to dissolve the lubricant in a solvent and apply the resulting solution to a ferromagnetic metal thin film. The solution may be coated or sprayed onto a ferromagnetic metal thin film type magnetic recording medium, or conversely, a ferromagnetic metal thin film type magnetic recording medium may be immersed in this solution and then dried.

〔Example〕

Next, embodiments of the invention will be described.

Example 1 Commercially available oleic acid was reacted with thionyl chloride (30(12) to obtain oleic acid chloride. Next, commercially available 1.1
．． 8- Trihydrotetradecafluorooctanoru 1 was dissolved in chloroform together with triethylamine, and the previously synthesized oleic acid chloride was added dropwise thereto over 1 hour at room temperature. After the dropwise addition, the mixture was stirred overnight at room temperature. . Thereafter, this was washed with water, 5% diluted hydrochloric acid, sodium bicarbonate solution, and water in this order, and after washing, it was purified by distillation under reduced pressure to obtain an aliphatic carboxylic acid fluoro group-containing alkyl ester derivative.

On the other hand, CO was deposited on a polyethylene terephthalate film having a thickness of 14 μm by an oblique vapor deposition method to form a ferromagnetic metal thin film layer having a thickness of 1000 μm.

Next, a solution prepared by dissolving 10.50 g of the aliphatic carboxylic acid fluoro group-containing alkyl ester derivative obtained by the above synthesis in 500 g of n-hexane was applied to the surface of this ferromagnetic metal thin film layer, and an 8-width A magnetic tape was produced by cutting it into pieces.

Example 2 In the synthesis of the aliphatic carboxylic acid fluoro group-containing alkyl ester derivative in Example 1, commercially available linoleic acid was replaced with thionyl chloride (SO
An aliphatic carboxylic acid fluoro group-containing alkyl ester derivative was synthesized in the same manner as in Example 1, except that linoleic acid chloride synthesized by reacting with Cfg) was used, and this was used in the same manner as in Example 1 to obtain a ferromagnetic metal. It was coated on the surface of a thin film layer to produce a magnetic tape.

Example 3 In the synthesis of the aliphatic carboxylic acid fluoro group-containing alkyl ester derivative in Example 1, commercially available lylunic acid was substituted with thionyl chloride (SOC) instead of oleic acid chloride.
An aliphatic carboxylic acid fluoro group-containing alkyl ester derivative was synthesized in the same manner as in Example 1, except that linoleic acid chloride synthesized by reacting with A magnetic tape was produced by applying it to the surface of a metal thin film layer.

Example 4 In the synthesis of the aliphatic carboxylic acid fluoro group-containing alkyl ester derivative in Example 1, commercially available myristic acid was substituted with thionyl chloride (S
An aliphatic carboxylic acid fluoro group-containing alkyl ester derivative was synthesized in the same manner as in Example 1, except that myristic acid chloride synthesized by reacting with OCf was used,
This was applied to the surface of the ferromagnetic metal thin film layer in the same manner as in Example 1 to produce a magnetic tape.

Example 5 In the synthesis of the aliphatic carboxylic acid fluoro group-containing alkyl ester derivative in Example 1, commercially available palmitic acid was replaced with thionyl chloride (S
An aliphatic carboxylic acid fluoro group-containing alkyl ester derivative was synthesized in the same manner as in Example 1, except that palmitic acid chloride synthesized by reaction with OCf□) was used. A magnetic tape was produced by applying it to the surface of a metal thin film layer.

Example 6 In the synthesis of aliphatic carboxylic acid fluoro group-containing alkyl ester derivative in Example 2, 1.1.8-)
Commercially available 1.1, 2.2. -An aliphatic carboxylic acid fluoro group-containing alkyl ester derivative was synthesized in the same manner as in Example 1, except that tetrahydrotridecafluorooctanoru-1 was used, and this was used in the same manner as in Example 1 to form a ferromagnetic metal thin film. It was coated on the surface of the layer to produce a magnetic tape.

Example 7 In the synthesis of the aliphatic carboxylic acid fluoro group-containing alkyl ester derivative in Example 4, 1.1.8-)lihydrotetrade-fluorooctanol-1 was replaced with
Commercially available 1.1.2.2. -An aliphatic carboxylic acid fluoro group-containing alkyl ester derivative was synthesized in the same manner as in Example 4, except that tetrahydrotridecafluorooctanoru-1 was used, and this was used in the same manner as in Example 4 to form a ferromagnetic metal thin film. It was coated on the surface of the layer to produce a magnetic tape.

Comparative Example 1 A magnetic tape was produced in the same manner as in Example 1, except that the coating treatment of the aliphatic carboxylic acid fluoro group-containing alkyl ester derivative on the surface of the ferromagnetic metal thin film layer was omitted.

Comparative Example 2 Commercially available oleic acid was reacted with phosphorus pentachloride (P(us)) to obtain oleic acid chloride.

On the other hand, thionyl chloride (S) was prepared by using pentadecafluorooctanoic acid as a catalyst with dimethylformamide.

C/! , ) and then reduced with lithium aluminum hydroxide to synthesize pentadecafluoro-1-octatool.

Next, this pentadecafluoro-1-octatool was dissolved in chloroform together with triethylamine, and the previously synthesized oleic acid chloride was added thereto under water cooling.
The mixture was added dropwise over 0 minutes, and after the addition was completed, the mixture was stirred overnight at room temperature.

Thereafter, this was washed with water, 5% diluted hydrochloric acid, sodium bicarbonate solution, and water in this order, and after washing, it was purified by distillation under reduced pressure to obtain a carboxylic acid perfluoroalkyl ester derivative.

The thus obtained carboxylic acid perfluoroalkyl ester derivative was applied to the surface of the ferromagnetic metal thin film layer in the same manner as in Example 1 to produce a magnetic tape.

Regarding the magnetic tapes obtained in each example and comparative example,
The coefficient of dynamic friction was measured under the conditions of a temperature of 25°C, a relative humidity of 50%, and -5°C, and shuttle durability, still durability, and head clogging were investigated. The coefficient of dynamic friction was measured using a guide pin made of stainless steel (SO3304) and running at a speed of 5 cm/sea with a constant tension applied.

Shuttle durability was evaluated by running the shuttle for 2 minutes each time, and determining the number of shuttle runs until the output decreased by 13 d.B. Furthermore, still durability was evaluated by measuring the decay time for the output to -3 dB in a paused state. Head clogging is determined by observing the dirty state of the magnetic head under a microscope after running it 200 times at 25 degrees Celsius. The judgment was divided into three levels: (medium) and (slight) if reproducible.

Table 1 below shows the results.

Table 1 [Effects of the Invention] As is clear from Table 1 above, the magnetic tapes (Examples 1 to 7) obtained using the aliphatic carboxylic acid fluoro group-containing alkyl ester derivatives obtained according to the present invention Compared to the magnetic tape obtained in Comparative Example 1 (Comparative Example 1), both have a smaller dynamic friction coefficient under both room temperature and low temperature conditions, and are extremely stable in running. Furthermore, compared to the magnetic tapes obtained in Comparative Examples 1 and 2 (Comparative Examples 1 and 2), the shuttle durability and still durability were excellent, and head clogging was significantly improved. For these reasons, the aliphatic carboxylic acid fluoro group-containing alkyl ester derivative obtained in the present invention and the lubricant containing this aliphatic carboxylic acid fluoro group-containing alkyl ester derivative are suitable for use in ferromagnetic metal thin film type magnetic recording media. It can be seen that it has extremely excellent lubricity, and its lubrication effect is maintained well even at low temperatures.

Claims (1)

[Claims] 1. General formula RCOOCH_2C_pF_mH_n (wherein R is an aliphatic hydrocarbon group, p is an integer of 4 or more, m is an integer of 2p-4≦m≦2p, and n is 1≦n≦ 5, and m+n=2p+1.) Aliphatic carboxylic acid fluoro group-containing alkyl ester derivative 2 represented by the general formula RCOOCH_2C_pF_mH_n (However, R in the formula is an aliphatic hydrocarbon group, and p is 4 or more. m is an integer of 2p-4≦m≦2p, n is an integer of 1≦n≦5, and m+n=2p+1.) lubricant