WO1998018804A1

WO1998018804A1 - Functionalized-phenoxy phosphazenes and use of same as a lubricant

Info

Publication number: WO1998018804A1
Application number: PCT/US1997/016651
Authority: WO
Inventors: Ted A. Morgan; Chester E. Pawloski; Kishore Kar
Original assignee: The Dow Chemical Company
Priority date: 1996-10-28
Filing date: 1997-09-17
Publication date: 1998-05-07

Abstract

Functionalized-phenoxy phosphazenes and use of same as lubricants for magnetic recording media are disclosed. In particular, cyclic phosphazenes having six or eight atoms in the ring structure and having at least one trifluoromethylphenoxy group; hydroxyphenoxy, aminophenoxy, carboxymethyl phenoxy, cyanophenoxy, 2-hydroxyethoxyphenoxy groups or a combination thereof; and, optionally, fluorophenoxy groups.

Description

FUNCTIONALIZED-PHENOXY PHOSPHAZENES AND USE OF SAME AS

A LUBRICANT

The present invention relates to functionalized-phenoxy phosphazenes and their use as lubricants on magnetic recording media.

Phosphazene fluids are known to be useful as lubricants, hydraulic fluids, fuel additives, flame retardants and for many other purposes. Polyfluorosubstituted cyclophosphazenes are particularly useful as lubricants and lubricant additives. However, tribological performance, even within a generic class of compounds, is unpredictable and dependent upon many different variables.

As magnetic recording media become capable of greater recording densities, the lubricants used must be capable of forming into a thin film and having durability under the required operating conditions. In use of these media, a recording head is positioned in very close proximity to the recording media and frequently contacts the recording media. This contact causes wear of the thin layer of magnetic material on the recording media and shortens the useful life of the recording media. With insufficiently effective lubricants, problems result including increased friction, scratching, and adhesion. Therefore, new efficient lubricants are desirable.

The first embodiment of the present invention is a group of phosphazenes useful as lubricants or lubricant additives. In particular these compounds are useful as lubricants on magnetic media. The phosphazene(s) of the present invention corresponds to Formulae:

In Formulae I and II, each X is independently -F, -(CF₂)_nCF₃, -OCF₂CF₂Br

-(CH₂)_nOH, -(CH₂)_nOR, -(CH₂)_nNH₂, -(CH₂)_nNR₂, -(CH₂)_nNO₂, -(CH₂)_nCO₂H, -(CH₂)_nCO₂R, -(CH₂)_nC(O)R, -(CH₂)_nCN, -(CH₂)_nSH, -(CH₂)_nSR, -(CH₂)_nSO₂NR₂, -(CH₂)_nSO₂R, -(CH₂)_nNHC(O)R, -(CH₂)_nNHC(O)OR, -(CH₂)_nNHC(O)NH₂, -O(CH₂CH(R)O)_nH, -O(CH₂CH₂O)_nH, -O(CF₂)_nCF₃-, -(CH₂)„CH(O), -(CH₂)_nC(O)NR₂, or a perfluoropolyethereal chain having a molecular weight range from 400 to 10,000 grams/mole; wherein each R is independently selected from the group consisting of a through C₁₂ linear or branched aliphatic hydrocarbon moiety; n is 0 to 3; and q is 1 or 2; with the proviso that at least one X is -F, -(CF₂)_nCF₃, -O(CF₂)_nCF₃, -OCF₂CF₂Br or a perfluoropolyethereal chain; and at least one X is -(CH₂)_nOH, -(CH )_nOR, -(CH₂)_nNH₂, -(CH₂)_nNR₂, -(CH₂)_nNO₂, -(CH₂)_nCO₂H, -(CH₂)_nCO₂R, -(CH₂)„C(O)R, -(CH₂)_nCN, -(CH₂)_nSH, -(CH₂)_nSR, -(CH₂)_nSO₂NR₂, -(CH₂)_nSO₂R, -(CH₂)_nNHC(O)R, -(CH₂)_nNHC(O)OR, -(CH₂)_nNHC(O)NH₂, -O(CH₂CH(R)O)_nH, -(CH₂)_nCH(O), or -(CH₂)_nC(O)NR₂. Further, if X is -F, then at least one of the remaining X's must be other than -OH or -NH₂. Thus, this phosphazene would not have only -F and -OH moieties nor only -F and -NH₂ moieties. Each X is located in the ortho, meta or para position; preferably the meta position. Preferably, the phosphazene is of Formula I. Preferably q is one. Preferably, each R is independently a linear or a branched C] to C₃ aliphatic hydrocarbon moiety. Preferably, n is 0.

The term perfluoropolyethereal chain as used above means substituents composed of repeating units selected from:

(a) -(CF₂CF₂CF₂O)-;

(b) -(CF(CF₃)-CF₂O)-; (c) -(CF₂CF₂O)-;

(d) -(CF₂CF₂O)- and -(CF₂O)

(e) -(CF(CF₃)-CF₂O)- and -(CFJO)-, where J is -F or -CF3;

(f) -(CF(CF₃)-CF₂O)-, (CF₂CF₂O)-, and -(CFJO)-, where J is -F or -CF₃;

(g) -(CF(CF₃)-CF₂O)- and -(CYG-CF₂CF₂O)-, where Y and G are independently F, Cl, or H; (h) -(OCF₂Q)-, where Q is a C]-C ₆ perfluoro moiety; (i) -(CF₂Q)-, where Q is a C]-C₃₆ perfluoro moiety; (j) -[(OCH₂CH₂)_n-OCH₂Q]-, where Q is a C C₃₆ perfluoro moiety; and (k) -[(OCH₂(R)CH)_nOCH₂Q]-, where Q is a CrC₃₆ perfluoro moiety. A perfluoro moiety includes perfluoroalkyl, perfluoropolyetherial groups or a combination thereof. The perfluoropolyetherial chain is preferably from 400 to 4,000 grams/mole.

A second embodiment of this invention is a magnetic recording medium comprising a substrate having a magnetic recording lamina deposited thereon, wherein the lamina comprises magnetic particles and a phosphazene as described in the first embodiment of the present invention. A third embodiment of this invention is a process for lubricating a surface by applying to the surface a functionalized-phenoxy phosphazene corresponding to the first embodiment. Due to the combination of substituents on the phosphazenes of this invention, these phosphazenes provide good adsorption properties. Good adsorption prevents the lubricant from migrating significantly on the surface under normal operating conditions.

The functionalized-phenoxy phosphazenes of this invention are those of the first embodiment of this invention as described above. The term "phosphazene" refers to a ring with alternating phosphorus and nitrogen atoms which ring has two substituents on each phosphorus atom. For example, triazatriphosphorine is a cyclic phosphazene containing three alternating phosphorus and nitrogen atoms with two substituents on each of the three phosphorus atoms.

The phosphazenes of this invention comprise phosphazenes having functionalized-phenoxy groups. A phenoxy group is a substituent of formula -O(C₆H₅). Thus, the term "functionalized-phenoxy group" as used herein refers to a substituent on a phosphorus atom of a phosphazene ring such that the substituent is of formula -O(C₆H₅__q)(X)_q. This structure is depicted in Formulae I and II.

In the aforementioned Formulae I and II, when n=0, the X substituents are of formula: -F, -CF₃, -OH, -OR, -NH₂, -NR₂, -NO₂, -CO₂H, -CO₂R, -C(O)R, -CN, -SH, -SR, -SO₂NR₂, -SO₂R, -NHC(O)R, -NHC(O)OR, -NHC(O)NH₂, -OCF₃, -CH(O) or -C(O)NR₂. Respectively, these substituents may be called fluoro, trifluoromethyl, hydroxy, alkoxy, amino, dialkylamino, nitro, carboxy, alkoxy carbonyl, acetyl, cyano, mercapto, alkylthio, dialkylsulfamoyl, alkylsulfonyl, alkanomido, (alkoxycarbonyl)amino, trifluoromethoxy, formyl, and formamido.

At least one X group is preferably a perfluoroalkyl substituent: -(CF₂)_nCF₃ where n is zero to three. Most preferably, n is 0 and the perfluoroalkyl substituent is a 3-trifluoromefhylphenoxy group. This X group may be derived from a functionalized phenol of formula HO(C₆H₄)(CF₂)_nCF₃ where n is zero to three. The term "functionalized phenol" refers to a molecule of formula Z(C₆H₄)OH where Z is fluoro, a perfluoroalkyl substituent, or a substituent from which a desired substituent, X, can be derived. Functionalized phenols wherein n is zero are known in the art. Functionalized phenols of formula HO(C₆H₄)(CF₂)_nCF wherein n is one to three may be prepared from commercially available starting materials and as described in I&EC Product Research and 5 Development, "Synthesis and Properties of Some m-bis[m(perfluoroalkyl)phenoxy] benzenes", (1968) pp. 101-107.

Preferably, in Formulae I and II above, at least one X is -CF₃; at least one X is -F; and at least one X is -(CH₂)_nOH, -(CH₂)_nOR, -(CH₂)_nNH₂, -(CH₂)_nNR₂, -(CH₂)_nNO₂, o -(CH₂)_nCO₂H, -(CH₂)„CO₂R, -(CH₂)„C(O)R, -(CH₂)_nCN, -(CH₂)_n-(CH₂)_nSH, -(CH₂)_nSR,

-(CH₂)_nSO₂NR₂, -(CH₂)_nSO₂R, -(CH₂)„NHC(O)R, -(CH₂)_nNHC(O)OR, -(CH₂)_nNHC(O)NH₂, -O(CH₂CH(R)O)_nH, -O(CH₂CH₂O)_nH, -(CH₂)_nCH(O) or -(CH₂)_nC(O)NR₂. More preferably, in addition to at least one X being -CF₃ and at least one X being -F, at least one X is -OH, -NH₂, -CH₂CO₂CH₃, -CN, -NO₂, -C(O)CH₃, -SO₂NR₂, 5 -OCH₂CH₂OH, or -C(O)NR₂. Even more preferably, at least one X is -CF₃; at least one X is -F; and at least one X is -NH₂, -OH, -CH₂CO₂CH₃, -CN, -(CH₂)₂OH, or -OCH₂CH₂OH.

Preferably, the phosphazene of the present invention comprises three different types of X substituents. The phosphazene is preferably fully substituted with -F, -CF₃, and o one other type of X substituent. Most preferably, the third type of X substituent is of formula -O(CH₂CH₂O)_nH; or of formula -(CH₂)„CN wherein n is 0 to 3.

Another preferred combination of substituents is a phosphazene corresponding to Formula I or Formula II wherein each X is independently -F, -(CF₂)_nCF₃, 5 -(CH₂)₂OH, -NHC(O)CH₃, or -CH₂CO₂CH₃; with the proviso that at least one X is

-(CF₂)_nCF₃; at least one X is -F; and at least one X of the remaining X's are selected from the group consisting of -(CH₂)₂OH, -NHC(O)CH₃, and -CH₂CO₂CH₃, wherein n is 0 through 3. Preferably, n is 0.

0 In the phosphazenes of this invention, all substituent groups on a molecule are sterically compatible with each other and chemically compatible with the process conditions. The term "sterically compatible" is employed to designate substituent groups which are positioned such that reactions with other molecules are not substantially retarded. Chemically compatible means the substituent groups on the phosphazenes do not react to form significant by-products.

Typically, the functionalized-phenoxy phosphazenes of the present invention are prepared by reacting suitable functionalized phenols (preferably including 3-trifluoromethylphenol) and a suitable cyclic phosphazene (preferably hexachloro-l,3,5-triaza-2,4,6-triphosphorine) in an inert organic solvent along with a hydrogen chloride acceptor such as potassium carbonate, under conditions and for a time period sufficient to yield the desired phenate which then reacts with the cyclic phosphazene to produce a functionalized-phenoxy phosphazene. The term "phenate" refers to the salt of a functionalized phenol. Typically, the reaction takes place under ambient pressures, although pressure is not critical and subatmospheric or superatmospheric pressures may be employed.

"Functionalized phenols" may be reacted successively or simultaneously with a cyclic phosphazene. Preferably, such functionalized phenols are chosen from the group consisting of molecules of formula CF₃(C₆H₄)OH, F(C₆H₄)OH, CH₃C(O)HN(C₆H₄)OH, PhC(O)O(C₆H₄)OH, CH₃OC(O)CH₂(C₆H₄)OH, HOCH₂CH₂O(C₆H₄)OH and CN(C₆H₄)OH which are called trifluoromethylphenol, fluorophenol, hydroxyphenyl acetamide, benzoyloxy resorcinol, methyl-hydroxyphenyl acetate, 2-hydroxyethoxy phenol and 4-cyanophenol, respectively. The order of addition of the reactants is not critical. However, agitation, such as stirring, is useful in ensuring uniformity of reactant concentrations in the reaction mix.

The preferred reactant hexachloro-l,3,5-triaza-2,4,6-triphosphorine is also called phosphonitrilic chloride trimer and hexachlorocylclotriphosphazene. Other cyclic phosphazenes, such as tetra and penta, can be reacted in the same manner described above. The reactant phosphazene should have six or eight atoms in the ring structure depending on the number of atoms in the ring structure of the desired final product. The phosphazene starting material is preferably fully substituted with halogen atoms. Preferably, such halogen is chloro or fluoro. Most preferably, the halogen is chloro. For example, a fully chloro- substituted phosphazene ring is a suitable phosphazene reactant. The minimum molar ratio of functionalized phenol to cyclic phosphazene starting material is dependent upon the halide content of the latter. Generally, a slight molar excess, one to ten mole percent, of functionalized phenol ensures complete halide substitution. Mixes of partially halide substituted and completely halide substituted product may provide the properties sought. In these cases, using a smaller molar ratio of phenol to phosphazene may be preferred economically.

In this process, the solvent need only be inert in the reaction system and be capable of solubilizing the reactions under reaction conditions. For example, solvents such as diglyme, tetraglyme, toluene, xylenes, mesitylene, dimethyl formamide, and dimethyl sulfoxide and mixtures thereof may be suitable. To achieve convenient temperature control, the process of the present invention is preferably run at reflux conditions, and thus, in these preferred cases, the solvent used is one which will provide reflux at the chosen process temperature. A preferred solvent is a mixture of xylenes and diglyme in a ratio of from 5: 1 to 10: 1.

The reaction occurs at a temperature that will vary depending on the starting materials and solvent. The subject process is generally run within the temperature range of from 50 to 140 degrees Celsius and is more typically the reflux temperature. High yields are generally obtained when the process temperature is within the temperature range of from 100 to 140 degrees Celsius. Temperatures substantially lower than 50 degrees Celsius may produce the product sought; however, the yield is predicted to be low and reaction times long. While the subject process is preferably run under reflux conditions, it is to be understood that reflux conditions need not be used. Other temperature control techniques can be used such as reactor immersion in a controlled temperature bath.

The reaction time for the process of this invention should be sufficiently long to achieve the desired substitution of the halo substituents initially present in the chlorocyclophosphazene reactant. The rate of substitution is interrelated with process temperature. After initiation, the higher the temperature used, the shorter the reaction period will be. Generally speaking, for the temperature range of 100 to 140 degrees Celsius, the reaction period will be 8 hours to 4 hours depending in part on the amount and type of starting materials used.

Some functionalized-phenoxy phosphazenes may require a second process step to prepare, for example, those products having the following X substituents: -SH, -OH, -(CH₂)_nNH₂, -(CH₂)_nCO₂H. The two step process is characterized by a substitution reaction followed by a deprotection reaction. The following, respectively, are examples of functionalized phenols which may be used in the two step process to derive desired X substituents listed immediately above: PhC(O)O(C₆H₄)OH, CH₃C(O)HN(C₆H₄)OH, HO(C₆H₄)(CH₂)CO₂CH₃. These functionalized phenols are known in the literature or are commercially available.

When step two is employed, step two of the process entails deprotecting the product of step one to produce a functionalized-phenoxy phosphazene having desired functional groups. The product may be deprotected or converted to the final product by processes such as hydrolysis or hydrogenolysis. Specifically, the deprotection step two, for esters and amides, may be carried out in the presence of an acid catalyst such as concentrated HC1 of from 5N to 12N or concentrated H₂SO of from 18N to 36N. The concentration of the acid can vary depending on reaction conditions. The mixture is typically refluxed at 50 to 100 degrees Celsius for 4 to 8 hours. More preferably, the temperature is 80 to 100 degrees Celsius.

An alternate method of preparation involves the use of phase transfer catalysis. The starting phenols may be converted to their corresponding phenoxides by dissolving in an aqueous solution of base (equimolar), such as Na₂CO₃, NaOH, or tetramethyl ammonium hydroxide, as well as a catalytic amount (1-5 mol percent) of a tetraalkyl ammonium salt, such as tetrabutyl ammonium bromide. To this solution (or vice versa) is added a solution of the phosphonitrilic chloride in an organic solvent such as chlorobenzene or toluene. The reaction mixture may be stirred vigorously and heated (25 °C to reflux), if necessary. On completion of reaction, the layers are separated, and the organic layer is washed (for example, three times with dilute aqueous NaOH or Na₂CO₃, and then with water). The organic layer is then dried over MgSO₄, filtered and then concentrated. The resulting crude product can be purified by chromatography or distillation.

The product phosphazenes can be recovered and purified by standard techniques such as by filtration, recrystallization, distillation, and chromatography. Various specific examples of preparing these phosphazenes are provided, below, in the "Examples" section. Product recovery on a commercial scale may be achieved by passing the product through a column of adsorbent, such as carbon, silica gel, alumina, or ion exchange resin rather than via distillation.

Any number of functionalized-phenoxy phosphazenes can be prepared using the processes described. These phosphazene materials may be used with other multifunctional compounds to produce new polymers. Alternatively, the phosphazenes could be used as intermediates to produce oils useful as lubricants and also may be used in conjunction with various additives. The phosphazenes of this invention may themselves be used as additives with other lubricant fluids to form lubricant mixtures. In addition, the phosphazenes of this invention may be used alone as a lubricating fluid.

When used as an additive to a lubricant fluid, the phosphazenes of the present invention should be compatible with the lubricant fluid; in other words, the compounds of the present invention should be readily dispensable or soluble in the lubricant fluid to form a homogeneous or non-homogeneous blend, either with or without the addition of an appropriate surfactant; and preferably should not be antagonistic to the lubricity of the present compounds. An example of lubricant fluids useful in conjunction with the phosphazenes of this invention include perfluoropolyether oils as described, for example, in WO 96/01303, page 5, lines 13-31.

When used as an additive in combination with another lubricant fluid, the phosphazenes are employed in an amount sufficient to increase the lubricity (or antifriction effect) of the lubrication mixture. Preferably, the phosphazenes are employed in a concentration, based on the weight of the lubricating fluid component, of at least 0.001 weight percent, more preferably greater than 0.01 percent, and most preferably greater that 0.1 percent. Preferably, the phosphazenes are employed in a concentration of less than 10 weight percent, more preferably less than 5 percent, and most preferably less than 2 percent.

Another embodiment of the invention is a magnetic recording medium with a 5 substrate having a magnetic recording lamina deposited thereon wherein the lamina comprises magnetic particles and at least one phosphazene of the present invention. The substrate generally comprises a non-magnetic metal or a plastic such as polyester (for example, polyethylene terephthalate). The lamina may comprise a thin film having an average thickness of 1 to 2000 Angstroms (10^"10 to 2 x 10^"7 meters). The magnetic recording o lamina may also comprise a metal evaporated tape. Examples of magnetic recording media include high density rigid disks, ultra high density floppy disks, digital audio tapes and video tapes which can be read by a magnetic recording head.

If a magnetic tape is used as the magnetic recording media, the lubricant may 5 be applied, for example, as follows. The tape may be passed through a bath containing the lubricant and taken up onto a reel. The amount of lubricant may be controlled, for example, by dragging the tape over a knife edge to remove excess lubricant. The lubricated tape may then be passed through a hot air drier to evaporate the solvent used in the bath.

o The present invention is also a process for lubricating a surface by applying the phosphazene of this invention to the surface, which preferably comprises a magnetic medium. Preferably, the phosphazene is applied to the surface to provide a lubricant film having an average thickness of 1 to 2000 Angstroms (10^~10 to 2 x 10^"7 meters) on the surface. The phosphazene is typically applied to magnetic media using a volatile solvent. 5

The following examples are provided to illustrate the present invention but should not be construed to limit the scope thereof. In the examples, the reactants useful for the process of the present invention may be obtained from commercial sources, such as Aldrich Chemical, and the solvents used are of commercial grade. The products are either o flash distilled using a Kugelrohr apparatus under reduced pressure or an adsorbent bed. The structures of the titled compounds are confirmed by IR, NMR, and MS spectra. Example 1 Preparation of mono(3-aminophenoxy)2,2,4,4,6,6-hexahydro-2,2,4,4,6- pentakis(3-trifluoromethyl)phenoxy)-l,3,5-triaza-2,4,6-triphosphorine:

Into a flask was placed 33 grams (g) of 3-hydroxyphenyl acetamide, 178 g of 3-trifluoromethylphenol, 200 milliliters (mL) of diglyme, 750 mL of xylene, 182 g of potassium carbonate and 70 g of hexachloro-l,3,5-triaza-2,4,6-triphosphorine. This mixture was stirred at reflux for sixteen hours. After cooling, the mixture was washed twice with 500 mL portions of water. The product phase was stirred with 200 mL of concentrated HC1 and 100 mL of water at reflux for six hours. After cooling, the product phase was separated and treated with enough fifty percent sodium hydroxide solution to neutral pH (7.0). The mixture was stirred for two hours and washed twice with 500 mL portions of water. The product phase was separated and passed through sodium sulfate. Low boilers were distilled off at 100 degrees Celsius (°C) under reduced pressure of 20 mrnHg. The product was further distilled at 210 °C and 0.5 mmHg to produce 158 g of oil.

In a similar manner, mono(4-amino-phenoxy)2,2,4,4,6,6-hexahydro- -2,2,4,4,6,6-pentakis(3-trifluoromethyl)phenoxy)-l,3,5-triaza-2,4,6-triphosphorine was prepared by substituting 4-hydroxyphenyl acetamide for the 3-hydroxyphenyl acetamide used above.

Example 2 Preparation of 2,2,4,4,6,6 hexahydro-mono(3-hydroxyphenoxy)-2,2,4,4,6 pentakis(3-trifluoromethyl)phenoxy)-l,3,5-triaza-2,4,6-triphosphorine:

Into a flask was placed 48 g of benzoyloxy resorcinol, 178 g of 3-trifluoromethylphenol, 200 mL of diglyme, 600 mL of xylene, 186 g of potassium carbonate and 70 g of hexachloro-l,3,5-triaza-2,4,6-triphosphorine. This mixture was stirred at reflux for twelve hours. After cooling, the mixture was washed twice with 500 mL portions of water, separated, and added to 150 mL of concentrated HC1 solution and 200 mL of water. This mixture was stirred at reflux for six hours. After cooling, the mixture was neutralized with sodium bicarbonate. The product phase was separated and washed twice with 500 mL portions of water. The product phase was separated, passed through sodium sulfate, and low boilers were distilled off. The product was further distilled at 280°C and 0.5 mmHg to produce 98 g of an oil.

In a similar manner, 2,2,4,4,6,6 hexahydro-bis(3-hydroxyphenoxy)tetrakis(3- 5 trifluoromethyl)phenoxy)-l,3,5-triaza-2,4,6-triphosphorine was prepared by using more benzoylexy resorcinol and less 3-trifluoromethylphenol than stated above resulting in a 4:2 molar ratio of trifluoromethylphenol to benzoyloxy resorcinol.

Example 3 Preparation of mono(4-carboxymethylphenoxy)2,2,4,4,6,6-hexahydro- 0 2,2,4,4,6 pentakis(3-trifluoromethyl)phenoxy)-l, 3, 5-triaza-2,4,6- triphosphorine:

Preparation of 2,2,4,4,6,6 hexahydro-mono(4-(methoxyaceto)- phenoxy)pentakis(3-trifluoromethyl)phenoxy)-l,3,5-triaza-2,4,6-triphosphorine as a starting 5 material was described first. Into a flask was placed 18.3 g of methyl-4- hydroxyphenylacetate, 89 g of 3-trifluoromethylphenol, 100 mL of diglyme, 400 mL of xylene, and 93 g of potassium carbonate and 34.8 g of hexachloro- 1,3,5- triaza-2,4,6-triphosphorine. This mixture was stirred at reflux for sixteen hours. After cooling, the mixture was washed twice with 500 mL portions of water, separated, passed o through sodium sulfate, and low boilers were distilled off under reduced pressure. The product was further distilled at 260 to 280°C and 0.5 mmHg to produce 91 g of an oil.

Into a flask was placed 80 g of 2,2,4,4,6,6 hexahydro-mono(4- (methoxyaceto)phenoxy)-2,2,4,4,6-pentakis(3-trifluoromethyl)phenoxy)-l,3,5-triaza-2,4,6- 5 triphosphorine, the preparation of which was described above, 200 mL of methanol, and 100 mL of a twenty percent sodium hydroxide solution. This mixture was stirred at reflux for eight hours. After cooling, 50 mL of concentrated HC1 solution was added and the mixture was stirred for one hour. The product layer was separated and washed twice with 300 mL portions of water. The product layer was again separated and passed through sodium sulfate. o Low boilers were distilled off under reduced pressure. The product was further distilled at

300°C and 0.5 mmHg to produce 47 g of an oil. Example 4 Preparation of a mixture of 4-fluorophenoxy-, 3-(trifluoromethyl) phenoxy and 2-(hydroxyethoxy)phenoxy-substituted derivatives of 2,2,4,4,6,6-hexahydro-l,3,5-triaza-2,4,6-triphosphorine with the major derivative being bis(4-fluorophenoxy)-2,2,4,4,6,6-hexahydro-mono- (2-hydroxyethoxy)phenoxy)-tris(3-trifluoromethyl)phenoxy- 1 ,3,5-triaza-

2,4,6-triphosphorine:

To a 2-liter four-necked round bottom flask equipped with an overhead stirrer, Dean-Stark trap with reflux condenser, an addition funnel, and a nitrogen inlet and outlet (reaction under nitrogen), was added 108.1 g (0.667 mol) of 3-trifluoromethylphenol, 37.6 g (0.336 mol) of 4-fluorophenol, 51.4 g (0.335 mol) of 2-hydroxyethoxyphenol, 70 milliliters (mL) of diglyme, 500 mL of o-xylene, and 106 g (1.325 mol) of 50 percent aqueous NaOH. The mixture was heated to reflux with stirring and the water removed via azeotropic distillation through the Dean-Stark trap. After all of the water was removed, a solution of 69.9 g (0.20 mol) of phosphonitrilic chloride in 275 mL of o-xylene was added over 30 minutes to the reaction mixture at reflux. After heating at reflux for 5 to 6 hours, the reaction mixture was allowed to cool to room temperature. The phases were then separated, and the organic phase was washed 2 times with 250 mL 10 percent aqueous NaOH and 2 times with 250 mL water and then dried over MgSO₄, filtered, and concentrated to give 49 g of a pale yellow oil. The molecular weights calculated for C₃₈H_{29 5}N₃OgP₃,

and C₄₂H₂₉F₁₃N₃O₈P₃, were 843, 885, 1093, 1085 and 1043 respectively. Mass spectrometric peaks were found corresponding to each of these molecular weights.

Example 5 Preparation of a mixture of 4-cyanophenoxy-, 4-fluorophenoxy-, and

3-(trifluoromethyl) phenoxy-substituted derivatives of 2,2,4 ,4,6,6-hexahydro- l,3,5-triaza-2,4,6-triphosphorine with the major derivative being mono(4-cyanophenoxy)-bis(4-fluorophenoxy)-2,2,4,4,6,6-hexahydro- tris(3-trifluoromethyl)phenoxy)-l,3,5-triaza-2,4,6-triphosphorine:

To a 2-liter 4-necked round bottom flask equipped as in Example 4 above and run under nitrogen atmosphere, was added 107.4 g (0.663 mol) of 3-trifluoromethylphenol, 37.2 g (0.332 mol) of 4-fluorophenol, 39.5 g (0.332 mol) of 4-cyanophenol, 70 mL of diglyme, 500 mL of o-xylene, and 106 g (1.325 mol) of 50 percent aqueous NaOH. The mixture was heated to reflux with stirring and the water removed via azeotropic distillation through the Dean-Stark trap. After all of the water was removed, a solution of 70g (0.20 mol) of phosphonitrilic chloride in 275 mL of o-xylenes was added over 30 minutes to the reaction mixture at reflux. After heating at reflux for 5 to 6 hours, the reaction mixture was allowed to cool to room temperature. The phases were then separated and the organic layer was washed with 10 percent aqueous NaOH (2x 250 mL) and water (2x 250mL). The organic layer was magnesium dried over sulfate, filtered, and then concentrated to give 72 g of a yellow-orange oily solid. The molecular weights calculated for C₃ H₂ F₅N O₆P₃, C₄₂H₂₄F₁₅N₄O₆P₃, and C₄ιH₂₄Fι₃N₄O₆P₃ were 808, 1058, and 1008 respectively. Mass spectrometric peaks were found corresponding to each of these molecular weights.

Comparative Example: Preparation of Phosphazene Used for Comparison

A phosphazene having exclusively -F and -CF substituents might be prepared as described in U.S. Patent No. 5,230,964 to Kar, column 7, lines 5-55. Specifically, the phosphazene lubricant used in the following examples was a mixture of 4-fluorophenoxy- and 3-(trifluoromethyl) phenoxy-substituted derivatives of 2,2,4,4,6,6- hexahydro-l,3,5-triaza-2,4,6-triphosphorine with the major derivative being bis(4-fluorophenoxy)2,2,4,4,6,6-hexahydro-2,2,4,6-tetrakis (3-trifluoromethyl)phenoxy)- 1 ,3,5-triaza-2,4,6-triphosphorine.

Example A CSS Test:

The lubricants described in Examples 4 (Lube 1), and 5 (Lube 2) and in the Comparative Example (Lube 3) were tested as follows:

Unlubricated carbon-overcoated 3.75 inch (9.5cm) magnetic hard disks (Western Digital Corporation, Santa Clara, CA) were cleaned for 10 minutes in hexane using an ultra-sonic bath and allowed to air dry in a clean air hood (Class 100) for at least one hour. The disks were then submerged for five minutes in a 5 inch (12 cm) x 8 inch (20 cm) x 6 inch (15 cm) stainless steel container containing a 0.1 weight percent solution of the lubricant to be tested. The solution was then drained from the container at a rate of 1.0 inch (2.54 cm) per minute. The lubricants adsorbed/absorbed onto the disks during the residence time in the bath. Next, the disks were dried at room temperature in a clean air hood for at least 1 hour to evaporate solvent. The average lubricant film thickness on the carbon-overcoat magnetic hard disks was 5 to 20 angstroms.

The lubricated disks were tested to determine coefficients of friction and stiction after various stages of use according to the following procedure. A rigid disk and head wear test system (SD 8001, commercially available from Surface Dynamics, Alameda, CA) was used which was equipped with a two-rail aluminatitanium carbide slider (MS-13-T13-05-XI, Rank Technologies) having a rail flatness (crown) of +0.5 to +3 .5 microinch, a microinch finish of the air-bearing surface (ABS), a camber of -1 to +1 microinch, a twist of -2 to +2 microinch, an edge blend of 100 microinch minimum to 300 microinch maximum, no cracks or scratches wider than 0.3 microinch, and enclosed chips no larger than 4 microinch width by 5 microinch length (1 microinch = 2.54 x 10^"8 meter). The head wear test system measured the static and dynamic friction between the hard magnetic disk and slider, and was controlled by a host computer equipped with MEGASISS software. During the test, the lubricated hard magnetic disks were loaded into the head wear test system and spun such that the surface velocity of the disk was 3.4 x 10⁴ inches per minute at a radial distance of 1.5 inch (3600 ram, 8.6 x 10⁴ cm per minute) with a 5 gram head load. At 3600 rpm, the slider was suspended over the disk due to the flow of air between the slider and the disk surface. During the test, the disk speed was periodically slowed until the slider touches the disk. After every 1000 cycles, the coefficient of friction was measured and recorded at 5 rotations per minute. The coefficient of stiction (the force required to start the disk) was measured during the first 30 milliseconds of each cycle. The results of the testing are reported below in Tables 1 and 2. In the Tables, the column termed "Contact Start-Stop Cycle" shows the number of times the disk was started and stopped, the phrase "Coef. Fric." means coefficient of friction, and the phrase "Coef. Stic." means coefficient of stiction. Table 1

Example B Spin-Off Test:

The lubricants described in Example 4 (Lube 1), Example 5 (Lube 2), and the Comparative Example (Lube 3) were evaluated for their adsorption/absoφtion ability on the magnetic disk carbon overcoat by measuring the reduction in lubricant film thickness on the magnetic disk after high speed spinning. A layer of phosphazene

Table 2

lubricant was applied to a magnetic disk as described in Example A above. IR absorbance at 1330 cm^"1 was used to monitor relative film thickness changes. The disk was then rotated at ambient temperature at 10,000 rotations per minute (rpm) and the thickness of the lubricant layer relative to the initial thickness was measured after 24 and 72 hours of spinning. The average data from 2 test runs each of the lubricants corresponding to those described in Examples 4, 5 and the Comparative Example above are shown in Table 3.

Table 3 Absolute IR Absorbance at 1330 cm^"1

Claims

CLAIMS:

1. A phosphazene corresponding to Formulae

wherein: each X is independently -F, -(CF₂)_nCF₃, -OCF₂CF₂Br -(CH₂)_nOH, -(CH₂)_nOR, -(CH₂)_nNH₂, -(CH₂)_nNR₂, -(CH₂)_nNO₂, -(CH₂)_nCO₂H, -(CH₂)_nCO₂R, l o -(CH₂)„C(O)R, -(CH₂)_nCN, -(CH₂)_nSH, -(CH₂)_nSR, -(CH₂)_nSO₂NR₂,

-(CH₂)_nSO₂R, -(CH₂)_nNHC(O)R, -(CH₂)_nNHC(O)OR, -(CH₂)„NHC(O)NH₂, -O(CH₂CH(R)O)_nH, -O(CH₂CH₂O)_nH, -O(CF₂)_nCF₃-, -(CH₂)_nCH(O), -(CH₂)_nC(O)NR₂, or a perfluoropolyethereal chain having a molecular weight range from 400 to 10,000 grams/mole; 15 wherein each R is independently a Cj through Cι₂ aliphatic hydrocarbon moiety; n is 0 to 3; and q is 1 or 2; with the proviso that at least one X is -F, -(CF₂)_nCF₃, -O(CF₂)_nCF₃, -O CF₂CF₂Br or a perfluoropolyethereal chain; and at least one X is -(CH₂)_nOH, -(CH₂)_nOR, -(CH₂)_nNH₂, -(CH₂)_nNR₂, -(CH₂)_nNO₂, -(CH₂)_nCO₂H, -(CH₂)_nCO₂R, -(CH₂)„C(O)R, -(CH₂)_nCN, -(CH₂)_nSH, -(CH₂)_nSR, -(CH₂)_nSO₂NR₂, -(CH₂)_nSO₂R, -(CH₂)_nNHC(O)R, -(CH₂)_nNHC(O)OR, -(CH₂)_nNHC(O)NH₂, -O(CH₂CH(R)O)„H, -(CH₂)„CH(O), or -(CH₂)_nC(O)NR₂; 5 with the further proviso that when X is -F, at least one of the remaining X's is other than -OH or -NH₂.

2. The phosphazene of Claim 1 wherein at least one X is -CF₃.

o 3. The phosphazene of Claim 1 wherein at least one X is -F.

4. The phosphazene of Claim 1 wherein at least one X is -CF₃; at least one X is -F; and all remaining X's are individually -(CH₂)_nOH, -(CH₂)_nNH , -CH₂CO₂CH₃, -CN, -NO₂, -C(O)CH₃, -SO₂NR₂, -OCH₂CH₂OH, -NHC(O)CH₃ or -C(O)NR₂, wherein n is 0 to 3. 5

5. The phosphazene of Claim 4 wherein the remaining X's are individually -NH₂, -OH, -CH₂CO₂CH₃, -CN, or -OCH₂CH₂OH.

6. The phosphazene of Claim 4 wherein the remaining X's are individually o -(CH₂)₂OH, -NHC(O)CH₃, or -CH₂CO₂CH₃.

7. A magnetic recording medium comprising a substrate having a magnetic recording lamina deposited thereon, said lamina comprising magnetic particles and at least one phosphazene as described in Claim 1. 5

8. A process for lubricating a surface, wherein said process comprises applying the phosphazene of Claim 1 to the surface.

9. The process of Claim 8 wherein the surface comprises a magnetic o recording medium.

10. The process of Claim 8 wherein the phosphazene is applied to the surface provide a lubricant film having an average thickness of 1 to 2000 Angstroms (10^"10 to 2 x ^"7 meters) on the surface.