JPH06220185A - Production of perfluoropolyether by infrared laser - Google Patents

Abstract

(57) [Summary] (Modified) [Constitution] A method for producing a perfluoropolyether by irradiating an infrared laser with at least one kind of perfluoroolefin and oxygen as raw materials. [Effect] By this method, the perfluoropolyether and its thin film can be formed at low cost with high yield and high efficiency. By providing the recording medium member with the lubricant layer by this method, it is possible to maintain the sliding resistance of the recording medium to the head for a long period of time and prevent the head and the recording medium from adhering to each other through the lubricant during the stop. As a result, the corrosion resistance of the recording medium is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing perfluoropolyether by infrared laser irradiation, and more particularly to the production of perfluoropolyether by laser reaction of a raw material gas containing perfluoroolefin and / or cyclic perfluoroether. The present invention relates to a method, a method for producing a perfluoropolyether thin film, and a method for producing a perfluoropolyether lubricant layer.

[0002]

2. Description of the Related Art A magnetic recording medium such as a magnetic recording disk (magnetic disk) used as a mass storage device of an electronic computer with which a head comes into contact has a non-magnetic substrate (aluminum, glass, graphite, etc.) on which the surface is sputtered. Ferromagnetic thin film (Cobalt / Nickel, Cobalt / Chromium, etc.) with protective film (amorphous carbon, cubic boron nitride (c-BN), yttria-stabilized zirconium oxide film, silicon oxide (SiO ₂ ) etc. ), And a perfluoropolyether thin film as a lubricant (main chain structure is (-CF (CF ₃ ) CF ₂ O-) _n , (-CF ₂ CF ₂ CF ₂ O-) _n , (-CF (CF ₃ ) CF
(CF ₃ ) O-) _n ) is applied and formed. The perfluoropolyether thin film acts as a lubricant molecular layer that enhances sliding resistance and corrosion resistance, and the adhesion of liquid to the protective film surface of the perfluoropolyether thin film improves the sliding resistance and corrosion resistance of the magnetic disk. It has a great influence. Usually, a perfluoropolyether thin film is manufactured by a coating method by immersing a magnetic disk in liquid perfluoropolyether and then washing with a solvent.

The perfluoropolyether liquid lubricant thin film is a film which is scattered by the sliding of the lubricant, changes in the lubrication performance at high and low temperatures, adhesion of the head and the magnetic disk by the lubricant, and a film in the process of applying the lubricant. There were problems in that the thickness was uneven and impurities were mixed. As a solution to this problem, a method of applying a perfluoropolyether lubricant containing an end group having an anchor function or an ultraviolet lamp (high pressure mercury lamp) using hexafluoropropene and oxygen as source gases
And UV laser (excimer laser, 4th harmonic of YAG laser) are applied to cause photo-oxidative polymerization on the surface of the protective film to form a perfluoropolyether lubricant thin film (Reference: Satoru Matsunuma, Japan. Chemistry Society Autumn Annual Meeting, Sapporo, 1991).

However, a lubricant such as perfluoropolyether having a terminal group having an anchor function has a low performance of adhering a non-metal compound such as amorphous carbon or silicon oxide onto a protective film, and also a lubricant. Since it is difficult to make the molecular layer uniformly thin, it cannot be applied to high recording density magnetic disks.
In addition, the method of forming a lubricant thin film on the surface of the protective film by irradiation with ultraviolet light is that ultraviolet lamps and ultraviolet lasers are expensive and energy conversion efficiency is low, so photon price is high, strong light cannot be obtained, However, there is a problem that the reaction efficiency is low due to its low light absorption coefficient.

[0005]

Therefore, the first aspect of the present invention
The purpose of is to provide an inexpensive method for producing perfluoropolyether in high yield. A second object of the present invention is to obtain a uniform, high-purity and high-performance perfluoropolyether thin film which is produced by photooxidative polymerization of a raw material on the substrate and adheres uniformly and firmly to the substrate surface with high yield and high yield. It is to provide a method of forming efficiently.

A third object of the present invention is to provide a method for forming a perfluoropolyether lubricant layer on a recording medium member having a substrate, a recording thin film and a protective film.

[0007]

The present inventors have made diligent efforts to solve the above-mentioned problems, and as a result, at least one perfluoroolefin and oxygen, at least one cyclic perfluoroether and optionally added oxygen, or at least A perfluoropolyether is produced by using one kind of perfluoroolefin, at least one kind of cyclic perfluoroether and optionally added oxygen as a raw material, adding a radical polymerization initiator to the above raw material as necessary, and irradiating an infrared laser. The inventors have found a method and completed the present invention.

That is, according to the first aspect of the present invention, at least one perfluoroolefin and oxygen, at least one cyclic perfluoroether and optionally added oxygen, or at least one perfluoroolefin, at least one cyclic perfluoroether and optionally added. The present invention provides a method for producing a perfluoropolyether by using oxygen as a raw material, adding a radical polymerization initiator to the above raw material as necessary, and irradiating an infrared laser.

In the second aspect of the present invention, a substrate is placed in an irradiation container, the inside of the irradiation container is depressurized to a predetermined pressure or lower, and then at least one perfluoroolefin and oxygen,
At least one cyclic perfluoroether and optionally added oxygen, or at least one perfluoroolefin, at least one cyclic perfluoroether and optionally added oxygen, further introduced a radical polymerization initiator, if necessary, infrared laser The method for producing a perfluoropolyether thin film is characterized by forming a perfluoropolyether thin film on the substrate by irradiating the substrate.

Furthermore, in the third invention of the present case, after an object is installed in the irradiation container and the inside of the irradiation container is depressurized to a predetermined pressure or less, at least one perfluoroolefin and oxygen, and at least one cyclic perfluoroether are optionally used. Oxygen added to, or at least one perfluoroolefin, at least one cyclic perfluoroether and optionally added oxygen, further, if necessary by introducing a radical polymerization initiator, by irradiating an infrared laser on the object The present invention provides a method for producing a perfluoropolyether lubricant layer, which comprises forming a perfluoropolyether thin film on.

The present invention will be described in detail below. The method of the invention utilizes infrared laser induced infrared multiphoton decomposition, thermal decomposition, dielectric breakdown, or a combination thereof. The reaction conditions in the method of the present invention may differ depending on which of the above reactions is used.

First, in the method of the first aspect of the present invention, the raw material gas is introduced into the irradiation container whose pressure is reduced to a predetermined pressure or less. In the method of the second aspect of the present invention, the substrate is placed in the irradiation container whose pressure is reduced to a predetermined pressure or lower, and the source gas is introduced. Further, in the third aspect of the present invention, the recording medium member including the substrate, the recording thin film and the protective group is installed in the irradiation container depressurized to a predetermined pressure or lower, and the raw material gas is introduced.

The irradiation vessel is depressurized to a pressure of 10 ^-2 Torr or less, preferably 10 ^-4 Torr or less. Pressure is 10 ^-2 To
If it is higher than rr, there is a problem that oxygen in the air affects the reaction and the substrate even when oxygen is not added. As a substrate that can be used in the method of the second invention of the present case, NaC
Examples thereof include substrates of inorganic materials such as l and KBr, substrates of all materials such as plastic, glass, ceramics, metals, semiconductors and organic materials. The thickness of the above substrate is not particularly limited, but is preferably 100 μm to 10 mm. It is preferable that the substrate is subjected to treatments such as cleaning, degreasing, drying, and removal of volatile matter.

Prior to the reaction, the substrate is -100 to
It is preferable to cool to 10 ° C. As a result, the perfluoropolyether produced in the gas phase can be strongly adsorbed on the substrate, and the radical polymerization reaction in the vicinity of the substrate or on the substrate causes the perfluoropolyether more strongly adsorbed on the substrate. The advantage arises that an ether film can be produced. Further, when the cooling temperature of the substrate is lower than -100 ° C, the raw material gas is adsorbed on the substrate, and the thermal reaction of the liquid or solid raw material on the substrate proceeds without the infrared laser reaction in the gas phase proceeding. When the substrate cooling temperature is higher than 10 ° C., the generated perfluoropolyether is difficult to adsorb on the substrate. Of the above temperature range, -70 to-
30 ° C. is particularly preferred.

Further, the substrate is preferably subjected to chemical modification such as oxidation, formation of a suitable chemical bond, dispersion or coating of a suitable atom or molecule on the surface of the substrate. Due to the above chemical modification, at least the end of the perfluoropolyether has an anchor function with respect to the substrate surface, and since the perfluoropolyether itself adsorbs well to the chemical modification, the perfluoropolyether more strongly adsorbed on the substrate. The advantage arises that thin films can be produced. Specifically, the chemical modification can be applied to both a dry process in which a chemical modifying gas is applied to a substrate and a wet process in which the substrate is dipped in a solution containing a modifying liquid or a modifying compound. Each can be carried out according to a conventional method. For example, as an example of a dry process, the surface can be oxidized by leaving the substrate in an oxygen atmosphere for several days.

Further, the substrate may be surface-treated by mechanical processing and / or surface processing. As an example of the mechanical processing, there is a small scratch on the surface of the substrate of about several tens to several hundreds of microns. Examples of surface processing include surface treatment with plasma or laser, glazing,
Examples include annealing, alloying, CVD, ablation, etching and the like.

The third aspect of the present invention also provides a method of providing a perfluoropolyether lubricant layer on an object, whereby the object is protected from sliding, corrosion, abrasion and the like. In the present specification, the term "lubricant layer" refers to a layer which is in contact with a substrate and rotates at a high speed, and which is attached to protect the substrate and has excellent sliding lubrication characteristics. The perfluoropolyether lubricant layer is used for a recording medium member such as a magnetic disk, a disc such as an optical disc and a magnetic tape, a bearing, a gear, a screw, etc., preferably for a recording medium member having a substrate, a recording thin film and a protective film. Can be provided.

As an example of the recording medium member, a recording thin film of cobalt / nickel, cobalt / chromium or the like is provided on a substrate of aluminum, glass, graphite or the like by a sputtering method or the like, and amorphous carbon is further formed thereon. Examples thereof include those provided with a protective film of cubic boron nitride, yttria-stabilized zircon oxide, silicon oxide or the like. The above-mentioned substrate and the object on which the perfluoropolyether lubricating layer is to be provided are
It is preferable to cool to -100 to 10 ° C before the reaction. As a result, there is an advantage that the reaction temperature on the substrate surface can be easily maintained uniformly. Also, the cooling temperature is -1
When the temperature is lower than 00 ° C., the raw material gas is adsorbed on the substrate, and the thermal reaction of the liquid or solid raw material on the substrate proceeds without causing the infrared laser reaction in the gas phase,
If the temperature is higher than 10 ° C, the generated perfluoropolyether is difficult to be adsorbed on the substrate. Of the above temperature range, −70 to −30 ° C. is preferable.

The perfluoroolefin as a raw material used in the present invention contains a perfluoroolefin having 2 to 6 carbon atoms. Specifically, perfluoroethylene, perfluoropropylene, 1- and 2-perfluorobutene, perfluoroallene, perfluorobutadiene, 1- and 2-perfluoropentene, perfluoroisoprene,
Perfluorohexene etc. can be mentioned. Of these, perfluoropropylene is preferable. The perfluoroolefins may be used alone or in combination of two or more. The above-mentioned perfluoroolefin is 1 to 50 Torr for performing an infrared multiphoton decomposition reaction, 50 to 1000 Torr for performing a thermal decomposition reaction, and 10 to 1 for performing a dielectric breakdown.
It is preferably introduced into the irradiation container whose pressure has been reduced at a pressure of 00 Torr. If the pressure is higher than this, the problems of infrared multiphoton decomposition reaction, thermal decomposition reaction, and dielectric breakdown do not occur, and if the pressure is lower than this, perfluoropolyether is sufficient even if each reaction occurs. There is a problem that the product is not produced with a high yield. Within the above pressure range, 10 to 30 Torr for performing the infrared multiphoton decomposition reaction, and 200 to 50 for performing the thermal decomposition reaction.
0 Torr, 10 to 50 Torr is particularly preferable for dielectric breakdown. The molar ratio of the perfluoroolefin to oxygen is preferably 1: 1 to 1: 100. When the ratio of oxygen is higher than this range, the efficiency of laser light absorption is low, and especially infrared multiphoton decomposition and thermal decomposition are unlikely to occur. Also, the efficiency of radical chain reaction involving oxygen molecules is reduced. As a result, there arises a problem that the production efficiency of the perfluoropolyether is lowered, and when the oxygen ratio is lower than this range, the perfluoropolyether is not produced and the perfluoropolyolefin is produced. Of the above ranges, 1: 2 to 1:10 are particularly preferable. The oxygen gas can be introduced before or after the introduction of the perfluoroolefin gas, or at the same time.

The cyclic perfluoroether used in the present invention includes a cyclic perfluoroether having 2 to 6 carbon atoms. Specifically, perfluoroolefin oxides such as perfluoroethylene oxide, perfluoropropylene oxide, and perfluorobutene oxide, perfluorooxetane, perfluorofuran, perfluoropyran, perfluorodioxetane, perfluorodioxane, and trifluoromethyl-substituted products of these cyclic perfluoroethers. Can be mentioned. Of these, perfluoropropylene oxide is preferable.
The above cyclic perfluoroethers may be used alone or in combination of two or more. The cyclic perfluoroolefin is contained in the irradiation container depressurized at a pressure of 1 to 50 Torr for performing an infrared multiphoton decomposition reaction, 50 to 1000 Torr for performing a thermal decomposition reaction, and 10 to 100 Torr for performing a dielectric breakdown. Is preferably introduced into If the pressure is higher than this, the infrared multiphoton decomposition reaction, thermal decomposition reaction and dielectric breakdown reaction do not occur, and if the pressure is lower than this, the perfluoropolyether does not have sufficient yield even if the respective reactions occur. There is a problem that it is not produced at a rate and a yield. Within the above pressure range, 10 to 30 Torr is used for infrared multiphoton decomposition reaction, 200 to 500 Torr for thermal decomposition reaction, and 10 to 5 for dielectric breakdown.
0 Torr is particularly preferred. Oxygen is optionally added to the cyclic perfluoroolefin to cause a photooxidative polymerization reaction. The molar ratio of cyclic perfluoroolefin to oxygen is 1: 1 to
1: 100 is preferable. If the proportion of oxygen is higher than this range, the efficiency of laser light absorption is low, and especially infrared multiphoton decomposition and thermal decomposition do not easily occur. Also, the efficiency of radical chain reaction involving oxygen molecules is reduced. As a result, there arises a problem that the production efficiency of perfluoropolyether decreases.
If the oxygen ratio is lower than this range, the problem occurs that perfluoropolyether is not produced. Of the above range, 1: 2 to 1: 5 is particularly preferable. The oxygen gas can be introduced before or after the introduction of the cyclic perfluoroether gas, or at the same time.

A mixture containing at least one of the above-mentioned perfluoroolefins and at least one of the above-mentioned cyclic perfluoroethers may be used as a raw material. Examples of preferable mixtures include perfluoropropylene and perfluoropropylene oxide, perfluoropropylene oxide and perfluoroethylene oxide, perfluoropropylene oxide and perfluorooxetane, and the like, of which perfluoropropylene and perfluoroethylene oxide are particularly preferable. The molar ratio of perfluoroolefin to cyclic perfluoroether is preferably 10: 1 to 1:10. If the ratio of the cyclic perfluoropolyether is higher than this range, the produced perfluoropolyether has a problem that the effect due to the mixed composition is not reflected so much, and if the ratio of the cyclic perfluoroether is lower than this range, the generated perfluoropolyether is generated. In the above, there arises a problem that the effect of the mixed composition is not reflected so much. Of the above ranges, 5: 1 to 1: 5 are particularly preferable. The above mixed gas is irradiated at a pressure of 3 to 50 Torr when performing an infrared multiphoton decomposition reaction, 50 to 700 Torr when performing a thermal decomposition reaction, and 3 to 100 Torr when performing a dielectric breakdown. It is preferably introduced into the container. This causes a problem that infrared multiphoton decomposition reaction, thermal decomposition reaction, and dielectric breakdown reaction do not occur at high pressure,
If the pressure is lower than this, there arises a problem that the perfluoropolyether is not produced in a sufficient yield even if the respective reactions occur. Of the above-mentioned pressure ranges, 10 to 30 Torr is particularly preferable for the infrared multiphoton decomposition reaction, 200 to 500 Torr for the thermal decomposition reaction, and 10 to 50 Torr for the dielectric breakdown. Oxygen is optionally added to the mixed gas to cause a photo-oxygen polymerization reaction.
The molar ratio of the mixed gas and oxygen is preferably 1: 1 to 1: 100. If the proportion of oxygen is higher than this range, the efficiency of laser light absorption is low, and especially infrared multiphoton decomposition and thermal decomposition do not easily occur. Also, the efficiency of radical chain reaction involving oxygen molecules is reduced. As a result, there arises a problem that the production efficiency of the perfluoropolyether is lowered, and when the oxygen ratio is lower than this range, the perfluoropolyether is not produced. Of the above range, particularly 1: 2-1:
5 is preferable. The oxygen gas can be introduced before or after the introduction of the mixed gas, or at the same time.

In the case of the batch method, a fixed amount of the above raw material is introduced into the reaction vessel through a vacuum system by a valve operation, and in the case of the continuous method, it is circulated in the irradiation vessel at a constant flow rate. For example, when the TEACO ₂ laser is irradiated at a repetition rate of 1 Hz, the raw material gas flow rate is preferably 0.1 to 10 liters / minute. Further, the raw material can be introduced as a molecular beam. Alternatively, the raw material can be introduced as a supersonic beam by ejecting the raw material into the vacuum cell from a nozzle.

Furthermore, if desired, a radical polymerization initiator may be added to the above raw materials. By adding the radical polymerization initiator, the photo-oxidative polymerization reaction of the present invention can be carried out with high efficiency. As the radical polymerization initiator, a compound that does not adversely affect the composition and physical properties of the generated perfluoropolyether, and that initiates radical polymerization of perfluoroolefin and / or cyclic perfluoroether is preferable, and specific examples include C ₂ F ₆ , CF ₃ OCF ₃ , CF ₃ OOCF ₃ , CF
₃ Br, CF ₃ I, C ₃ F ₈ , C ₃ F _{6 and the} like can be mentioned. Of these, CF ₃ OCF ₃ and CF ₃ OOCF ₃ are preferable. The above radical polymerization initiator is used in an amount of 0.1 to 1 based on the total pressure of the reaction raw materials.
It is added at a pressure of 0%, preferably 0.5-5%. The radical polymerization initiator can be introduced before, after, or simultaneously with the introduction of the raw material gas.

As the infrared laser used in the present invention, any laser which induces a photooxidative polymerization reaction of the above-mentioned raw materials can be used, but one having high energy conversion efficiency and relatively low photon cost is preferable. As an example, TEA
CO ₂ laser, NH ₃ laser, CF ₄ laser,
ρ-H ₂ Raman laser, D ₂ Raman laser, Nd:
Lasers such as YAG lasers and combinations thereof can be mentioned, among which TEACO ₂ lasers are preferred.

The wavelength of the laser used in the present invention is preferably adjusted to the wavelength at which at least one component of the raw material has strong absorption, and generally 400 to 4000 cm ^-1 is preferable. If the laser wavelength is longer or shorter than this range, there is a problem that the infrared absorption of the raw material is often absent. Of this range, 800 to 1200 cm ^-1 is particularly preferable. Also, when utilizing dielectric breakdown, the wavelength of the laser must be a wavelength that the raw material does not absorb. Generally, 400 to 4000 cm ^-1 is preferable.

The laser used in the present invention may be continuously irradiated, but pulse irradiation is preferable. The number of irradiation pulses is 1 to 10 ⁴ pul for infrared multiphoton decomposition reaction.
se, 1 to 10 ⁴ pulse is preferable when the thermal decomposition reaction is performed, and 1 to 10 ² pulse is preferable when the dielectric breakdown is performed. If the pulse number is larger than this range, a secondary reaction occurs, which causes a problem that the properties of the produced perfluoropolyether deteriorate. Within this range, 50 to 500 pulses are preferred for the infrared multiphoton decomposition reaction, 100 to 1000 pulses for the thermal decomposition reaction, and 1 to 10 pulses for the dielectric breakdown.

The time width of the pulse is preferably 1 ns to 1 μs for the infrared multiphoton decomposition reaction, 10 ns to 10 μs for the thermal decomposition reaction, and 1 ns to 1 μs for the dielectric breakdown. . If the time width is smaller than this range, there is a problem that no reaction occurs because there is no infrared laser of sufficient intensity, and if the time width is larger than this range, each reaction does not occur. For example, there is a problem that infrared multiphoton decomposition reaction does not occur and thermal decomposition occurs.
Within this range, 20 to 100 ns for infrared multiphoton decomposition reaction and 1 μs for thermal decomposition reaction.
10 μs, and particularly preferably 20 to 100 ns when dielectric breakdown is performed.

The pulse energy of the laser used in the present invention is preferably 0.05 to 30 J in any of infrared multiphoton decomposition reaction, thermal decomposition reaction and dielectric breakdown. If the pulse energy is smaller than this range, it is difficult for the raw material to supply enough photon energy to perform the light absorption necessary for each reaction, so there is a problem that each reaction does not occur. If the energy is large, there arises a problem that a lens for condensing the laser light and an optical system such as a window plate material for the laser light to enter the irradiation container are damaged. Within this range, 0.1 for both infrared multiphoton decomposition reaction, thermal decomposition reaction, and dielectric breakdown
-10 J is especially preferable.

The laser light density (fluence) in the vicinity of the focal point in the irradiation container is 50 to 1000 J / cm ² when an infrared multiphoton decomposition reaction is performed, and 50 to 1000 J when a thermal decomposition reaction is performed. / Cm ² , preferably 500 to 8000 J / cm ² when dielectric breakdown is performed. If the fluence is smaller than this range, the raw materials do not absorb the light necessary for each reaction, so there is a problem that each reaction does not occur.If the fluence is larger than this range, infrared multiphoton decomposition reaction or thermal decomposition occurs. The reaction does not occur, and dielectric breakdown occurs in all cases, and problems of damage to optical systems such as lenses and window plate materials occur. Of this range, infrared multiple-photon decomposition reaction 50~500J / cm ² in the case of performing, 100~500J / cm ² in the case of performing the thermal decomposition reaction, 1500~3000J / cm in the case of dielectric breakdown ² is particularly preferred.

The laser irradiation time (reaction time) is determined by the number of laser pulses and the repetition rate of laser pulses. For example, the repetition rate of laser pulse is 1
In the case of Hz, 1 second to 3 when performing infrared multiphoton decomposition reaction
The time is preferably 1 second to 3 hours when the thermal decomposition reaction is performed, and 1 second to 2 minutes when the dielectric breakdown is performed. When the reaction time is longer than this range, a secondary reaction occurs, which causes a problem that the properties of the produced perfluoropolyether deteriorate. Within this range, 1 minute to 10 minutes is particularly preferable for the infrared multiphoton decomposition reaction, 2 minutes to 20 minutes for the thermal decomposition reaction, and 1 second to 10 seconds for the dielectric breakdown. preferable. These reaction times can be reduced by increasing the repetition rate of the laser pulse. For example, when the speed is 100 Hz, the reaction time is 10 seconds at the longest in any reaction.

An example of preferable reaction conditions in the method of the present invention is shown in Table 1 below. Table 1 Reaction conditions of infrared multiphoton decomposition method, thermal decomposition method, dielectric breakdown method by TEA CO ₂ laser ─────────────────────────── ───────── Test conditions Infrared multiphoton decomposition Pyrolysis Dielectric breakdown ────────────────────────────── ───── Raw material Perfluoropropylene (PFP) + Oxygen pressure / Torr 25 + 75 100 + 350 100 + 350 Laser wavenumber (cm ^-1 ) 1041.28 1041.28 942.38 Raw material Perfluoropropylene oxide (PFPO) + Oxygen pressure / Torr 25 + 75 100 + 350 100 + 350 Laser wave number (cm ^-1 ) 1078.59 1078.59 942.38 Raw material PFP + PFPO + Oxygen pressure / Torr 20 + 70 + 75 50 + 50 + 350 50 + 50 + 350 Laser wave number (cm ^-1 ) 1041.28 1041.28 942.38 Pulse number 1000 1000 1 Pulse width 100ns FWHM + 100ns FWHM + 100ns FWHM + 1.3μs tail 1.3μs tail 1.3μs tail Pulse energy (J) 0.3 0.3 1.6 scan Ruens (J cm ^-2 ) 380 380 2000 Reaction time 12 m 12 m Is ───────────────────────────────── The perfluoropolyether produced by the method of the present invention is represented by the following general formula.

(CFRCF₂CF₂O)_x− (CFRCF₂O)_y− (CFRO)_z However, R is independently F or CF₃X,
y and z change depending on the experimental conditions. Polymerization of monomer
The degree changes depending on the experimental conditions, but is approximately 10 ²Oh
Of the resulting perfluoropolyether
Molecular weight is 10^FourIt is an order.

Furthermore, by introducing a carrier gas into the irradiation container and thereby moving and collecting the gas product produced by the above reaction, the amount of perfluoropolyether produced can be increased. Examples of the carrier gas include helium, argon, nitrogen and the like, preferably helium and argon. The carrier gas can be changed from an equivalent amount to several hundred times the amount of the raw material gas. The amount of carrier gas introduced may be 1 to 2000 Torr. If the amount of carrier gas introduced is higher than this range,
There is a problem that each reaction does not occur, and if the amount of carrier gas introduced is less than this range, there is a problem that it does not act as a carrier gas. this house,
10 to 500 Torr is preferable.

The above-mentioned introduction of the carrier gas can be carried out before or after the introduction of the raw material gas, or at the same time. Further, the carrier gas can be introduced by a batch method or a distribution method. The perfluoropolyether formed on the inner wall of the window plate before and after the incidence of the laser may be attached and stained to reduce the transmittance of the window plate. In this case, there is a method of irradiating laser light while constantly blowing a fixed amount of carrier gas on the inner wall of the window plate. However, in this case, the introduction of the raw material gas is limited to the distribution method. In addition, the raw material gas and the carrier gas for the window plate must be sufficiently exhausted during the reaction by a vacuum pump having a large discharge amount.

An example of an apparatus that can be used in the method of the present invention will be described below. In FIG. 1, after passing 2 laser beams emitted from 1 TEA CO ₂ laser oscillator through 3 diaphragm plates,
The light was collected by a 4 infrared light lens and irradiated to the center of the 5 irradiation reaction container. A 7NaCl or KBr window plate is attached to the laser beam passage place of 5 and 6 sample gas is put inside. In addition, a substrate for forming a polyfluoropolyether thin film can be attached inside the substrate 5 on a temperature-adjustable stage for substrate installation, and the substrate can be installed at various positions and angles with respect to laser light. The reaction of the raw material gas is carried out in a closed system by putting it inside 5, or by introducing the raw material gas from 10 gas inlets,
1 It was conducted by a distribution method by discharging from a gas outlet.

[0036]

The photon energy of infrared light is lower than that of ultraviolet / visible light, for example, the energy per photon of a CO ₂ laser is 2 kcal. Therefore, infrared light excitation cannot induce vibrational excitation of a molecule, and cannot induce a reaction such as ultraviolet / visible light that undergoes electronic excitation of a molecule. By the way, when a molecule is irradiated with a pulsed light of a strong infrared laser, after absorbing several tens of infrared photons per molecule, the molecule is in a high vibration excited state and has internal energy equal to or higher than a decomposition threshold value, Decomposes (infrared multiphoton decomposition).
The fluorine compound, which is the raw material gas for the perfluoropolyether thin film, has strong absorption in the wavelength region of the CO ₂ laser light, and thus can cause infrared multiphoton decomposition.

On the other hand, when the pressure of the source gas is high or in the condensed phase, the energy of the molecules in the high vibration excited state generated by the infrared multiphoton excitation is dispersed to the surroundings by collision, and thermal equilibrium is finally achieved. It becomes a high temperature gas. Therefore, thermal decomposition of the component of the raw material gas having a low decomposition threshold occurs. Further, when an infrared laser is focused by a lens having a short focal length and a high energy laser beam is applied to the raw material gas, dielectric breakdown of the raw material gas accompanied by light emission and explosion noise occurs near the focus, and the raw material gas is decomposed. In order to cause thermal decomposition by an infrared laser, it is necessary that at least one component of the source gas has strong absorption in the wavelength region of laser light. On the other hand, dielectric breakdown occurs regardless of the absorption of the raw material gas, so all molecules are targeted as the raw material gas.

For example, when TEA CO ₂ laser irradiation is performed using a mixed gas of perfluoropropylene and oxygen at a pressure of about several tens Torr or less as a raw material gas, a high vibration excited state of perfluoropropylene (CF ₃ CF = CF ₂ ). Of C
Infrared multiphoton decomposition occurs via F ₃ CF = CF ₂ †. (Equation 1,
2). CF ₃ CF = CF ₂ + nhν → CF ₃ CF = CF ₂ † (1) CF ₃ CF = CF ₂ † → · CF ₃ + · CF = CF ₂ (2) Is the pressure of the mixed gas as high as several hundred Torr or more? , When the total pressure is as high as several hundred Torr or higher with the addition of added gas, the energy of CF ₃ CF = CF ₂ molecules in the high vibration excited state is dispersed by collision, thermal equilibrium is achieved, and thermal decomposition occurs (Equation 3). that time,
The carbon-carbon bond with the lowest bond energy is cleaved (Equation 4).

CF ₃ CF = CF ₂ † + M → CF ₃ CF = CF ₂ + M + heat (3) CF ₃ CF = CF ₂ + heat → ・ CF ₃ + ・ CF = CF ₂ (4) (M = raw material gas) In the dielectric breakdown, CF ₃ CF = CF ₂ is ionized, and at the same time, a complicated dissociation reaction occurs, and as a result, various ions, such as CF ₃ , CF = CF ₂ and F, are generated (Equation 5).

[0040] _{· CF 3 CF = CF 2 →} · CF 3, · CF = CF 2, F , etc. (5) In this way initially radicals such generated · CF ₃ (abbreviated as R ·) is CF ₃ CF = CF ₂ acts as a radical oxidation polymerization initiator. That is, R · undergoes an addition reaction with CF ₃ CF = CF ₂ existing in the reaction system (Equation 6). Using this as an initiation reaction, an oxidative polymerization reaction by a radical chain reaction of CF ₃ CF = CF ₂ occurs in the presence of an enzyme, and finally a perfluoropolyether is produced (Equation 7). The composition of the perfluoropolyether varies by laser irradiation conditions _{but, (CF (CF 3 (CF} 2 O) x - represented by (CF ₂ O) _y.

R · + CF ₃ CF = CF ₂ → · CF (CF ₃ ) CF ₂ R (6) R · + nCF ₃ CF = CF ₂ + mO ₂ → perfluoropolyether (7) The produced perfluoropolyether is a production vessel. A perfluoropolyether thin film of appropriate thickness can be produced by depositing on the underlying substrate. The amount of perfluoropolyether produced can be increased by moving and collecting the gaseous product produced by the above reaction by the carrier gas.

In order to carry out the oxidative polymerization reaction with high efficiency,
A radical polymerization initiator having high reactivity with at least a monomer is desirable. Therefore, a starting material for generating an appropriate radical with high efficiency can be added to the monomer and oxygen. A uniform, strong-adhesion, high-purity, high-performance perfluoropolyether thin film can be produced, for example, by controlling the laser irradiation conditions. Alternatively, the substrate is cooled to cause R 3 to be generated by laser irradiation while CF ₃ CF = CF ₂ and oxygen are adsorbed and condensed at a high concentration on the substrate to cause an oxidative polymerization reaction on the substrate. it can. Alternatively, there is a method of producing perfluoropolyether by chemically modifying the surface of the substrate or forming an appropriate chemical bond, and then causing an oxidative polymerization reaction of the raw material monomer on the surface of the substrate. By these methods, it is possible to produce a uniform, strong adhesion, high purity and high performance perfluoropolyether thin film on the protective film of the non-metallic compound of the magnetic disk.

[0043]

Industrial Applicability According to the present invention, a perfluoropolyether can be produced by using an infrared laser having a mold intensity which is cheaper than an ultraviolet light source to cause photooxidative polymerization of a raw material. Further, according to the method of the present invention, a perfluoropolyether thin film can be formed on the surface of a substrate with high yield and high efficiency.

Further, according to the method of the present invention, it is possible to form a uniform, strong adhesion, high purity and high performance perfluoropolyether lubricant layer on an object. Furthermore, according to the method of the present invention, a perfluoropolyether of uniform, strong adhesion, high purity and high performance is formed on a protective film of a magnetic recording medium member having a substrate, a magnetic thin film for recording and a protective film of a non-metallic compound. A high recording density magnetic disk having a lubricant layer can be manufactured.

A feature of the high recording density magnetic disk having the lubricant layer manufactured by the present invention is that the scattering and fluidity of the perfluoropolyether lubricant can be improved. Therefore, the sliding resistance of the recording medium with respect to the head can be maintained for a long period of time, and further, the head and the recording medium can be prevented from adhering to each other via the lubricant during the stop. As a result, the corrosion resistance of the recording medium can also be improved.

[0046]

The preferred embodiments of the present invention will be described in detail by the following examples. The scope of the invention is not limited to the examples below. [Example 1] Fig. 1 shows an outline of an apparatus used in the present invention. The irradiation container 15 is a cylindrical cross-shaped Pyrex glass or metal chamber, and has a laser irradiation direction of 10 cm, a laser irradiation vertical direction of 5 cm, and an internal volume of 100 cm ³ .
The size of the irradiation container can be changed arbitrarily. A window plate 17 made of NaCl or KBr is attached to the end of the irradiation container. In addition, substrates for perfluoropolyether thin film analysis were installed at various places in the irradiation container. NaCl as the substrate,
A substrate of KBr and Ni-P plated A1 was used. The substrate has a square shape with a side of 5 mm to 10 cm or a disk shape with a diameter of 5 mm to 10 cm and a thickness of 10 μm to 1 cm. Since the substrate is installed on the stage whose position and angle can be changed arbitrarily, the distance and angle between the substrate and the laser beam can be set arbitrarily. The temperature of the substrate holding stage can be changed from -60 ° C to 300 ° C.
Further, for the method of irradiating the raw material gas while circulating it in the irradiation container (flow method), the inlet 10 for introducing the raw material gas is used.
There is also an exit 11. After sufficiently irradiating the irradiation container with a vacuum pump (vacuum degree of 10 ^-2 Torr or less), CF ₃ CF
A mixed gas 16 composed of CF ₂ (25 Torr) and oxygen (75 Torr) was introduced. After passing the beam 12 from the pulse oscillation TEA CO ₂ laser 11 through the diaphragm plate 13, it is narrowed down by the infrared light lens 14 having a focal length of 7.5 cm, and the irradiation container 15 is irradiated.
CF ₃ CF = CF ₂ (25 Torr) and oxygen (75 Tor
Irradiate the mixed gas 16 consisting of Raw material CF ₃ CF
The infrared absorption spectrum of = CF ₂ is shown in FIGS. 2 and 3.
CF ₃ CF = CF ₂ is 1 in the TEA CO ₂ laser oscillation region
It has absorption due to C—F bond at 020 to 1060 cm ⁻¹ . Therefore, the oscillation line of the TEA CO ₂ laser is 9 μm
The band P (26) 104 was 1.28 cm ^-1 . From the area of the beam at the focal point, the laser fluence at the focal point is 380 J · cm.
^-2 . Laser pulse repetition rate is 0.7Hz,
The pulse width was 100 ns FWHM +1.3 μs tail, the pulse energy was 0.3 J, and the number of pulses was 1000.

When laser irradiation was carried out for 12 minutes under these conditions, infrared multiphoton decomposition of CF ₃ CF = CF ₂ occurred, and perfluoropolyether was produced. After separating the gas product from the sample after the laser light irradiation, the inside of the irradiation container was sufficiently evacuated by a vacuum pump. Analysis of gas products includes Fourier transform infrared absorption measurement (FT-IR), gas chromatograph (G
C) -Mass spectrometer (MS). On the other hand, the substrate was removed from the irradiation container at room temperature in air, and the product attached on the substrate was analyzed. The composition of the perfluoropolyether obtained by this method has the general formula (CF ₂ (CF ₃ )
CF ₂ O) _x- (CF ₃ CFO) _y- (CF ₂ O) _Z
The degree of polymerization of ₃ CF = CF _{2 was on} the order of 10 ² and the molecular weight was on the order of 10 ⁴ . The analysis was performed by FT-IR, high-sensitivity reflection method FT-IR, ESCA, or the like.

From the analysis of the gaseous product, the product is COF₂,
CF₃CFO, CO₂, C₂F₆, C₂F_FourMet. However, COF₂Minutes of
CO with solution₂CO increases₂Is COF₂Decomposition of
It is a thing. In FT-IR spectrum measurement, COF₂
(1928, 1249, 965, 774, 626c
m^-1), CF₃CFO (1897, 1090cm^-1), CO₂(2
165 cm^-1), C₂F₆(1250, 1120 cm^-1), C₂F_Four
(1337, 1186 cm^-1) Characteristic absorption is observed
It As an example, 5 Torr CF₃CF = CF₂And 75 Torr
Mixture with oxygen as source gas, laser wave number 9P
(26) 1041.28 cm ^-1Laser fluence 38
4 J · cm^-2Gas after 1000 pulse irradiation at
The IR spectrum of the product is shown in FIG. In this case, GC-
Gas product is CO from MS₂, COF₂, CF₃CFO, C₂F₆And
I found out that

In GC-MS, the respective gas products were separated and the parent peak or peak of the corresponding fragment was observed. COF ₂ (m / e = 66), CF ₃ CF
O (m / e = 116 (C ₂ F ₄ O ⁺ ), 104 (CF ₄ O ⁺ ), 97
(C ₂ F ₃ O ⁺ ), 85 (CF ₃ O ⁺ ), 69 (CF ₃ ⁺ ), 66 (CF ₂
O ⁺ ), 50 (CF ₂ ⁺ ), 47 (CFO ⁺ )), CO ₂ (m / e
= 44 (CO ₂ ⁺ ), 28 (CO ⁺ )), C ₂ F ₆ (m / e = 11)
9 (C ₂ F ₅ ⁺ ), 69 (CF ₃ ⁺ ), 50 (CF ₂ ⁺ )), C ₂ F
₄ (m / e = 100 (C ₂ F ₄ ⁺ ), 81 (C ₂ F ₃ ⁺ ), 50
(CF ₂ ⁺ )).

On the other hand, the product deposited on the substrate was a perfluoropolyether thin film. NaCl or KBr
FT of perfluoropolyether thin film deposited on substrate
-In the infrared absorption spectrum by IR measurement, 123
An absorption attributed to the C—F bond is observed at 0 cm ⁻¹ (FIG. 5). In the case of Ni-P plated AI substrate, high sensitivity reflection method F
A wide absorption of C—F bond is observed around 1300 cm ⁻¹ by T-IR (FIG. 6). When the surface of the substrate was analyzed by ESCA, C, F, and O peaks were observed, and the C—F bond and C—C bond were observed from the respective binding energies.
It can be seen that it has a bond and a C—O bond (FIG. 7). All of these results indicate that a perfluoropolyether thin film is formed on the substrate. The film thickness of the perfluoropolyether thin film was several nanometers due to the film thickness dependence of infrared absorption intensity on the order of micrometers.

From the NMR spectrum, the degree of polymerization of CF ₃ CF = CF ₂ was about several hundreds. The average molecular weight was on the order of 10 ⁴ . Next, laser irradiation was performed by changing the laser irradiation conditions, and the absorbance at 1240 cm ^-1 of the substrate was measured by FT-IR. A mixture of 25 Torr CF ₃ CF = CF ₂ and 75 Torr oxygen was used as the source gas, and the laser wave number was 9 P (2
6) 1041.28 cm ^-1 , laser fluence 380 ±
When the pulse number was increased to 200 to 1500 at a constant value of 20 Jcm ⁻² , the 1240 cm ⁻¹ absorbance increased (FIG. 8).
However, even when the pulse number was increased from 1500 to 3000, the absorbance at 1240 cm ^-1 was almost constant.

A mixture of 25 Torr CF ₃ CF = CF ₂ and 75 Torr oxygen was used as the source gas, and the laser wave number was 9 P.
(26) When the laser fluence was increased to 200 to 400 Jcm ^-2 with the pulse number kept constant at 1041.28 cm ^-1 and 1000, the absorbance at 1240 cm ^-1 increased (Fig. 9). A mixture of 25 Torr CF ₃ CF = CF ₂ and oxygen was used as the source gas, and the laser wave number was 9P (26) 1041.28.
cm ^-1 , pulse number 1000, laser fluence 38
Keep the oxygen pressure constant at 3 ± 7 Jcm ^-2 and keep the oxygen pressure between 0 and 150 Torr.
When it was increased to r, the absorbance at 1240 cm ^-1 increased (Fig. 10).

A mixture of 75 Torr oxygen and CF ₃ CF = CF ₂ was used as a source gas, and the laser wave number was 9P (26) 104.
1.28 cm ^-1, the number of pulses 1000, the constant laser fluence and 383 ± 7Jcm ^-2, increasing the pressure of CF ₃ CF = CF ₂ to 0 to 16 Torr, the absorbance of 1240 cm ^-1 increased ( (Fig. 11). However, when the pressure of CF ₃ CF = CF ₂ was 16 to 25 Torr, the absorbance at 1240 cm ⁻¹ did not change so much, and at 30 to 35 Torr, the absorbance at 1240 cm ⁻¹ decreased slightly.

The absorbance at 1240 cm ^-1 by FT-IR measurement corresponds to the thickness of the perfluoropolyether thin film. The absorbance at 1240 cm ^-1 is the absorption due to the C—F bond of perfluoropolyether. Therefore, it can be seen that the higher the pulse number, laser fluence, and oxygen pressure, the greater the thickness of the thin film. Also,
When the pressure of CF ₃ CF = CF ₂ was 20 to 25 Torr, the thin film formation was maximum.

CF₃CF = CF₂Is TEA CO₂Laser
1035.8 cm in the oscillation range^-1Has absorption. So T
EA CO₂Set the laser oscillation line to 9P (10) 1055.
63 cm^-1~ 9P (30) 1037.40cm^-1Changed to
By the way, 1240 cm of thin film^-1The absorbance at 9P (2
6) 1041.28 cm^-1Compared to the case of
It was not (Fig. 12). But CF₃CF = CF₂Absorption of
9R (22) 1079.85 cm^-110R (2
0) 975.93 cm^-110P (22) 942.38cm ^-1of
When irradiated with a laser oscillator, perfluoropolyene
No tellurium film was formed. Example 2 CF of 50 Torr₃CF = CF₂And 350 Torr
Example 1 except that the raw material gas is a mixture with the above oxygen.
Perfluoropolyether was prepared in a similar manner.

In this method, the raw material gas was thermally decomposed, and as a result, perfluoropolyether was mainly obtained. The film thickness of the perfluoropolyether thin film on the substrate was several nanometers to several micrometers depending on the number of irradiation pulses. The infrared absorption spectrum of the perfluoropolyether formed on the glass substrate is shown in FIG. Example 3 A mixture of 25 Torr CF ₃ CF = CF ₂ and 75 Torr oxygen was used as a source gas, a TEA CO ₂ laser was strongly focused near the substrate, and a laser fluence at a focus was 2000 J · cm. ^A perfluoropolyether was produced in the same manner as in Example 1 except that dielectric breakdown of the raw material gas was caused near the focus as ^-2 .

In this method, plasma is generated in the vicinity of the focal point with a large spark sound, and the reaction of the raw material gas occurs,
As a result, mainly perfluoropolyether was obtained. The thickness of the perfluoropolyether thin film on the substrate is
It was several nanometers to several micrometres, depending on the number of irradiation pulses. The infrared absorption spectrum of the perfluoropolyether formed on the glass substrate is shown in FIG.

The production yield of perfluoropolyether was improved from 50% to about 10 times under the same conditions as in Example 1. Example 4 A mixture of 25 Torr CF ₃ CF = CF ₂ and 75 Torr oxygen was used as a source gas, 1 Torr CF ₃ OCF ₃ was used as a radical polymerization initiator, and the laser wave number was 10.
A perfluoropolyether was produced in the same manner as in Example 1 except that the R (14) of 6 μm was 971.93 cm ⁻¹ .

In this method, CF ₃ CF = CF ₂ itself does not absorb laser light, but infrared multiphoton decomposition of CF ₃ OCF ₃ occurs. As a result, generation · CF ₃ and · OCF _3, they act as an initiator of the oxidative polymerization reaction of CF ₃ CF = CF _2, perfluoropolyether is obtained mainly.
The film thickness of the perfluoropolyether thin film on the substrate was several nanometers to several micrometers depending on the number of irradiation pulses.

The infrared absorption spectrum of perfluoropolyether formed on the glass substrate is shown in FIG. Example 5 A perfluoropolyether was produced in the same manner as in Examples 1 to 4 except that the surface of the aluminum substrate was cooled to -50 ° C by controlling the temperature of the stage on which the substrate was placed.

In this method, the source gas is adsorbed on the substrate.
So TEA CO₂Laser generated by laser irradiation
CFAL that has reached the substrate surface and is adsorbed on the substrate surface₃CF
= CF ₂As an initiator of the surface oxidative polymerization reaction of oxygen with oxygen
Cal acts, and as a result, perfluoropoly
An ether film was formed. The obtained perfluoropoly
The thickness of the ether thin film depends on the number of irradiation pulses,
It was from a few meters to a few micrometers.

FIG. 16 shows an infrared absorption spectrum of perfluoropolyether prepared on an aluminum substrate by high-sensitivity reflection method FT-IR measurement. The substrate with the perfluoropolyether thin film formed on the surface was treated with 1,1,2-trichloro-1, which is a good solvent for perfluoropolyether.
It was washed with 2,2-trifluoroethane. After washing, the absorbance of the C—F bond of perfluoropolyether at 1240 cm ⁻¹ was measured by the high-sensitivity reflection method FT-IR spectrum, and there was no change from that before washing. Therefore, it was confirmed that the perfluoropolyether thin film was not separated by washing, and a perfluoropolyether thin film in which molecular ends were fixed to the surface was produced. Example 6 A surface of a 1 cm × 3 cm × 1 mm aluminum substrate was oxidized by performing plasma discharge in an oxygen atmosphere.

On the surface of a glass substrate of 1 cm × 3 cm × 2 mm, a sputtering method of aluminum metal or laser CVD using trimethylaluminum as a source gas is performed.
Method was used to deposit aluminum with a thickness of about 1 μm. Perfluoropolyether was produced in the same manner as in Examples 1 to 5 except that the above-mentioned aluminum substrate whose surface was previously oxidized and a glass substrate having a trace amount of aluminum deposited on the glass surface by sputtering were used. .

In this method, the source gas is adsorbed on the substrate.
So TEA CO₂Laser generated by laser irradiation
CFAL that has reached the substrate surface and is adsorbed on the substrate surface₃CF
= CF ₂As an initiator of the surface oxidative polymerization reaction of oxygen with oxygen
Cal acts, and as a result, perfluoropoly
An ether film was formed. The obtained perfluoropoly
The thickness of the ether thin film depends on the number of irradiation pulses,
It was from a few meters to a few micrometers.

Perfluor prepared on an aluminum substrate
Infrared measured by high-sensitivity reflection method of ropolyether thin film
The absorption spectrum is shown in FIG. Perfluoropo on the surface
The substrate with the polyether thin film was
1,1,2-trichloro-1, which is a good solvent for ether,
It was washed with 2,2-trifluoroethane. After washing, pel
Fluoropolyether C-F bond 1240 cm^-1Sucking
Luminous intensity was measured by high sensitivity reflection method FT-IR spectrum.
However, there was no change from before washing. Therefore, Perfluo
The low molecular weight polyether polyether film does not separate by washing,
The perfluoropolyether thin film with the
It was confirmed that it was done. Example 7 CF₃CF = CF₂Instead of hexafluorop
Use propylene oxide with propylene oxide
9R (20) 1078.5 which was in the absorption of pyrene oxide
9 cm ^-1Similar to Embodiments 1 to 6 except that
The method produced perfluoropolyether. On board
The film thickness of the perfluoropolyether thin film is the number of irradiation pulses
From a few nanometers to a few micrometers depending on
It was.

The infrared absorption spectrum of the perfluoropolyether formed on the glass substrate is shown in FIG. The CF ₃ CF = CF ₂ and hexafluoropropylene oxide in place of Example 8 CF ₃ CF = CF _2, pressure ratio 1: but using 1, similar to Example 1 to Example 6 METHOD To produce perfluoropolyether. The film thickness of the perfluoropolyether thin film on the substrate was several nanometers to several micrometers depending on the number of irradiation pulses. When the pressure ratio of CF ₃ CF = CF ₂ and hexafluoropropylene oxide was changed in the range of 5: 1 to 1: 5, the composition ratio of the raw material mixed gas was reflected in the composition of the generated perfluoropolyether.

The infrared absorption spectrum of perfluoropolyether prepared on a glass substrate is shown in FIG. [Example 9] 5 made of aluminum plated with Ni-P
Example 1 to Example 6 except that a recording medium member having an inch disk substrate on which a chromium film, a cobalt-Rickel magnetic film, and an amorphous carbon film were sequentially laminated by sputtering was used instead of the substrate. A perfluoropolyether was prepared in a similar manner to. The film thickness of the perfluoropolyether thin film on the recording medium member was several nanometers to several micrometers depending on the number of irradiation pulses.

The infrared absorption spectrum of the perfluoropolyether thin film formed on the glass substrate is shown in FIG. By this method, a perfluoropolyether thin film can be formed on the surface of the amorphous carbon film, and a magnetic recording medium in which this acts as a lubricant layer was manufactured.

[Brief description of drawings]

FIG. 1 shows a schematic diagram of an apparatus used in an embodiment of the present invention.

FIG. 2 shows 50 to 4000 of CF ₃ CF = CF ₂ as a raw material.
The infrared absorption spectrum of cm ^-1 is shown.

FIG. 3 shows that the raw material CF ₃ CF = CF ₂ of 1000 to 10
The infrared absorption spectrum at 80 cm ^-1 is shown.

FIG. 4 shows an infrared absorption spectrum of a gas product by FT-IR measurement.

FIG. 5 shows an infrared absorption spectrum of perfluoropolyether by FT-IR measurement.

FIG. 6 shows an infrared absorption spectrum of perfluoropolyether measured by a high-sensitivity reflection method FT-IR measurement.

FIG. 7 shows an ESCA spectrum of a perfluoropolyether thin film formed on a glass substrate.

FIG. 8 is a graph showing the relationship between the absorbance at 1240 cm ⁻¹ and the pulse number for a perfluoropolyether thin film. The source gas is 25 Torr of CF ₃ CF = CF ₂ and 75
Torr is a mixture with oxygen, laser wave number is 9P
(26) 1041.28 cm ^-1 , and the laser fluence was 380 ± 20 Jcm ^-2 .

FIG. 9 is a graph showing the relationship between the absorbance at 1240 cm ⁻¹ of a perfluoropolyether thin film and laser fluence. The source gas is 25 Torr CF ₃ CF =
It was a mixture of CF ₂ and 75 Torr oxygen, the laser wave number was 9P (26) 104 1.28 cm ⁻¹ and the pulse number was 1000.

FIG. 10 is a graph showing the relationship between absorbance at 1240 cm ⁻¹ and oxygen pressure by a perfluoropolyether thin film. The source gas was a mixture of 25 Torr CF ₃ CF = CF ₂ and oxygen, and the laser wave number was 9P (26) 10.
41.28 cm ^-1 , laser fluence is 383 ± 7
It was Jcm ^-2 and the pulse number was 1000.

FIG. 11 shows a perfluoropolyether thin film.
According to 1240 cm^-1Absorbance at CF and CF ₃CF = CF₂And the pressure of
It is a graph which shows the relationship of. CF is the source gas₃CF = CF₂When
It is a mixture with 75 Torr oxygen and has a laser wave number of 9
P (26) 104 1.28 cm ^-1And the laser fluen
Space is 383 ± 7 Jcm^-2And the number of pulses is 1000
It was.

FIG. 12 is a graph showing the relationship between the absorbance at 1240 cm ⁻¹ and the laser wave number of a perfluoropolyether thin film. The source gas is 25 Torr CF ₃ CF = CF
_It was a mixture of ₂ and 75 Torr oxygen, the laser fluence was 380 Jcm ^-2 , and the pulse number was 1000.

FIG. 13 shows an infrared absorption spectrum of perfluoropolyether by FT-IR measurement.

FIG. 14 shows an infrared absorption spectrum of perfluoropolyether by FT-IR measurement.

FIG. 15 shows an infrared absorption spectrum of perfluoropolyether by FT-IR measurement.

FIG. 16 shows an infrared absorption spectrum of perfluoropolyether measured by a high-sensitivity reflection method FT-IR measurement.

FIG. 17 shows an infrared absorption spectrum of perfluoropolyether measured by a high-sensitivity reflection method FT-IR measurement.

FIG. 18 shows an infrared absorption spectrum of perfluoropolyether by FT-IR measurement.

FIG. 19 shows an infrared absorption spectrum of perfluoropolyether by FT-IR measurement.

FIG. 20 shows an infrared absorption spectrum of perfluoropolyether by a high-sensitivity reflection method FT-IR measurement.

[Explanation of symbols]

1 TEA CO ₂ Laser Oscillator 2 Laser Light 3 Aperture Plate 4 Lens for Infrared Light 5 Irradiation Reaction Vessel (Cylindrical Pyrex Glass or Metal Chamber) 6 Sample Gas 7 NaCl or KBr Window Plate 8 Temperature Variable Stage for Substrate Installation 9 Substrate for forming a polyfluoropolyether thin film 10 Gas inlet 11 Gas outlet

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Satoru Matsunuma Satoru Matsunuma 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Pref., Institute of Industrial Science and Technology (72) Inventor Katsuo Abe 292 Yoshida-cho, Totsuka-ku, Yokohama, Kanagawa Production Technology Research Institute, Hiritsu Manufacturing Co., Ltd.

Claims (14)

[Claims] 1. A method for producing a perfluoropolyether by irradiating an infrared laser with at least one perfluoroolefin and oxygen as raw materials. 2. A method for producing a perfluoropolyether by irradiating an infrared laser with at least one cyclic perfluoroether and optionally added oxygen as a raw material. 3. A method for producing a perfluoropolyether by irradiating an infrared laser with at least one perfluoroolefin, at least one cyclic perfluoroether and optionally added oxygen as a raw material. 4. The method according to claim 1, wherein a radical polymerization initiator is added to the raw material. 5. A perfluoropolyether molecule of perfluoropolyether is controlled by controlling the wavelength, energy, pulse width and pulse number of infrared laser light used as a light source when producing perfluoropolyether by photooxidative polymerization. 4. The method according to any one of claims 1 to 3, which controls binding, composition, structure, distribution and orientation. 6. A substrate is placed in an irradiation container, the inside of the irradiation container is depressurized to a predetermined pressure or lower, at least one perfluoroolefin and oxygen are introduced, and the substrate is irradiated with an infrared laser. A method for producing a perfluoropolyether thin film, which comprises forming a perfluoropolyether thin film on the substrate. 7. A substrate is placed in an irradiation container, the inside of the irradiation container is depressurized to a predetermined pressure or lower, and then at least one cyclic perfluoroether and optionally oxygen are introduced and irradiated with an infrared laser. A method for producing a perfluoropolyether thin film, comprising forming a perfluoropolyether thin film on the substrate. 8. A substrate is placed in an irradiation container, the inside of the irradiation container is depressurized to a predetermined pressure or lower, and then at least one perfluoroolefin, at least one cyclic perfluoroether, and optionally oxygen are introduced, and infrared rays are emitted. A method for producing a perfluoropolyether thin film, comprising forming a perfluoropolyether thin film on the substrate by irradiating a laser. 9. The method according to claim 6, wherein the surface of the substrate is subjected to a treatment such as machining or surface treatment. 10. The method according to claim 6, wherein the substrate surface is cooled. 11. An object is placed in the irradiation container, the inside of the irradiation container is depressurized to a predetermined pressure or lower, at least one perfluoroolefin and oxygen are introduced, and the infrared laser is applied to the object for irradiation. A method for producing a perfluoropolyether lubricant layer, which comprises forming a perfluoropolyether thin film on the substrate. 12. An object is placed in an irradiation container, the inside of the irradiation container is depressurized to a predetermined pressure or lower, and then at least one cyclic perfluoroether and optionally oxygen are introduced and irradiated with an infrared laser. A method for producing a perfluoropolyether lubricant layer, comprising forming a perfluoropolyether thin film on the object. 13. An object is placed in an irradiation container, the inside of the irradiation container is depressurized to a predetermined pressure or lower, and then at least one perfluoroolefin, at least one cyclic perfluoroether and optionally oxygen are introduced, and infrared rays are emitted. A method for producing a perfluoropolyether lubricant layer, which comprises forming a perfluoropolyether thin film on the object by irradiating a laser. 14. The method according to claim 11, wherein the object is a recording medium member having a substrate, a recording thin film and a protective film.