JPH1053870A - Formation of diamond like carbon film on rubber or resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a member low in friction, having a long service life and easy to operate in such a manner that the characteristics of a rubber or resin base material are put to practical use by irradiating the base material with ultraviolet rays or electron beams, thereafter bringing gaseous hydrocarbon into vapor phase reaction and forming diamond like carbon film. SOLUTION: A soft rubber or resin base material enough in resiliency and calcinability is irradiated with ultraviolet rays and/or electron beams. In this way, the surface of the base material is cross-linked with high polymers, and furthermore, unbonded carbon atoms are numerously formed and dispersed therein. Then, this surface is preferably exposed to the plasma of a fluorine-contg. gas or a gaseous hydrogen and is coated, by which the unbonded carbon atoms are protected from contamination caused by impurities. After that, gaseous hydrocarbon is fed thereto as the raw material, which is excited, and vapor phase reaction is allowed to occur. This vapor phase reaction is executed by a plasma CVD process, an ion plating process, a sputtering process or the like in such a manner that methane or the like and a carrier gas are fed to the base material while it is cooled. Thus, the hard diamond like carbon film to which the unbonded carbon atoms are bonded and excellent in wear resistance is formed with tight adhesion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for forming a diamond-like carbon film (DLC) on a flexible material such as rubber or resin. Rubber is used for various purposes because of its excellent formability, flexibility and elasticity. It is used for sliders of wipers, valve seats of valves, O-rings of vacuum equipment, various packings and the like. It utilizes the characteristic of flexible deformation.

[0002] Resin is not as good as rubber, but it is also rich in elasticity and, above all, excellent in formability, and can be made at once by guiding the material into a mold and solidifying it in any shape. Can be. The diamond-like carbon film is a thin film of carbon having a diamond structure and has excellent hardness and wear resistance.

[0003]

2. Description of the Related Art Rubber is rich in flexibility and can be freely deformed according to any shape, and adheres closely to an object to cause large sliding friction. Although resin is not as good as rubber, it is often deformed according to the object and friction is also quite large. Rubber is sometimes used to prevent slippage. This actively utilizes the magnitude of friction. In many other cases, a large friction is acceptable. In that case there is no problem.

[0004] However, there is a special case in which a rubber product is preferable to have low sliding friction while utilizing flexibility. For example, in the case of rubber for an automobile wiper, it is better that the sliding resistance against a glass window wet with water is small. If the friction due to sliding is large, the rubber gradually wears out. In the case of a wiper, a powder of molybdenum disulfide MoS ₂ as a lubricant is adhered to the surface. Thereby, the sliding characteristics are improved. The abrasion resistance is also excellent, and the sliding of rubber against glass is good. However, if used for one year and two years, the molybdenum disulfide attached to the surface will peel off.

[0005] Then, the frictional resistance increases. Slippage against glass becomes worse. Since the glass surface has water, the rubber keeps sliding due to the lubricating action of water. However, resistance is increased because the property of low friction due to the lubricant is lost.
As a result, some of the rubber is worn away. If you look closely, fine jaggedness occurs on the rubber contact surface. When rubbed with a jagged wiper, the water pattern remains on the glass concentrically. Therefore, it is necessary to replace the wiper periodically or as needed.

[0006] Rubber is often used for packing of valves and the like. Rubber is easy to deform and can close even a space with fine irregularities. Rubber is used for valve seats and O-rings in addition to packing. Even if it says rubber, various things are used. They are in close contact with valve bodies, screws, and flanges and flex to completely block the flow of gas and liquid. Once sealed, the O-ring may be removed by removing the screw instead of not opening again. In the case of rubber packing for tap water, the shaft rotates while being strongly pressed against the shaft. If the sliding friction is large, the operability deteriorates. Rubber abrasion also increases. Rubber is often used as a valve seat (valve seat), but if it is kept closed for a long time, the valve body and the valve seat will strongly adhere. Forcibly turning the valve will damage the rubber sheet.

[0007] In order to overcome such disadvantages, for example, rubber may be impregnated with silicone oil. This oil has excellent lubricity and exhibits the effect of reducing friction by oozing out of rubber. But only this time it will be exhausted. Then, a high friction state is caused, and the rubber is easily damaged.

In addition, rubber may be used as a sliding member. Even in such a case, since the rubber itself is a material having a high coefficient of friction, the rubber is coated or impregnated with a low friction material. In any case, the exfoliation and wear are exhausted and disappear. Not enough to reduce friction forever. There is a demand for a technique that makes use of the soft properties of rubber to achieve low friction and excellent wear resistance.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a member which has a low friction and a long life and is easy to operate. Further, the resin is provided with a low friction and a long life.

Next, diamond-like carbon will be described. DIAMOND LIKE CARBON, abbreviated as DLC.
It has a diamond structure and is connected between carbons by sp ³ hybrid orbitals. There are several aspects of carbon. Graphite is hexagonal, black, conductive, soft and poor in wear. Diamond is cubic, extremely hard, insulating and transparent. Amorphous carbon partially has diamond bonds but does not have long-range order as a whole. Although this is only a thin film, it has excellent wear resistance and a low friction coefficient. It is produced by a CVD method using a hydrocarbon such as methane or ethane as a source gas.

[0011] Diamond-like carbon is the same as amorphous carbon. Since bulk bulk is not possible, it is made as a thin film on a substrate. The base material is a Si wafer, metal or the like. It rides cleanly on a smooth Si wafer. In the case of metal, a diamond-like carbon film can be formed. It is an excellent method for surface treatment of a sliding member because it is smooth and hard and has an action of protecting the inside. D
Although it was called an LC film, it was thought that it could be formed only on a solid having a smooth surface such as metal or Si. It seems that it is a matter of course that a solid substrate is used because a thin film can be held only by a rigid body, and a thin film cannot be formed unless the substrate is heated.

Many proposals have been made for improving the technology of coating DLC on a solid substrate. All are produced by a CVD method using hydrocarbon as a source gas. As the CVD method, a filament thermal CVD method in which a filament is energized and a raw material is excited by the heat, a thermal CVD method in which a susceptor is heated by a high frequency or resistance heating heater to excite a raw material gas, and a plasma is applied between electrodes by a high frequency and a direct current And a plasma CVD method in which a source gas is excited by plasma, a microwave plasma CVD method in which a source gas is excited by microwaves, and an optical CVD method in which a source gas is optically excited by a lamp. There are various types depending on the excitation method. In addition to the above, there are an ultraviolet excitation method and an electron beam excitation method.

Japanese Patent Application Laid-Open No. 61-147679 discloses a method in which a diamond-like carbon film is formed on a Si wafer by a photo-CVD method using ultraviolet excitation. Mercury lamp,
It is stated that a diamond film or a diamond-like carbon film is formed when ultraviolet light from an excimer laser is decomposed by being applied to a raw material gas composed of a hydrocarbon gas and a hydrogen gas and then flown on a heated Si wafer.

Japanese Patent Application Laid-Open No. 61-151096 discloses that a Si wafer is irradiated with an electron beam under conditions that do not cause gas discharge.
Further, the raw material gas is flown, and the raw material gas is excited by an electron beam to generate 6
The film is heated to about 00 ° C. to cause a gas phase reaction to form a diamond thin film or a diamond-like carbon film.

All of these are for forming a diamond-like carbon film on a metal or Si wafer. In order to excite the gas, filament heating, high-frequency heating, resistance heating, microwave, high-frequency discharge, DC discharge, visible light, ultraviolet light, electron beam, and the like are used. Ultraviolet rays and electron beams provide energy for decomposing gas. It performs the same function as heat, microwaves, and high-frequency vibrations. However, there is no rubber coated with a diamond film or a diamond-like carbon film.

The reason may be as follows. The substrate must be heated to a fairly high temperature for film formation. Rubber will not withstand such high temperatures. It is also expected that even if rubber could be coated with a film, a thin film would be obtained if the rubber expands and contracts. Moreover, it does not seem to be noticed that there is any benefit to coating the rubber with a diamond-like carbon film.

Under these circumstances, no attempt has been made to coat rubber with diamond-like carbon. However, coating rubber with a diamond-like carbon film as described above has certain benefits. The first object of the present invention is to coat a diamond-like carbon film on rubber. A second object is to coat a resin with a diamond-like carbon film as a similar substance. A third object of the present invention is to realize a material having a low coefficient of friction while being flexible by coating a soft rubber with a diamond-like carbon film. It is a fourth object of the present invention to provide a material that is flexible and has excellent sliding properties.

[0018]

Means for Solving the Problems A rubber or resin base material is irradiated with an electron beam or ultraviolet ray to cause a cross-linking reaction to generate a large number of unbonded carbon on the surface. Is coated with a diamond-like carbon film. Alternatively, the substrate is exposed to plasma of any of fluorine-containing gas and hydrogen gas after electron beam irradiation and ultraviolet irradiation, and then the diamond-like carbon film is coated by a plasma CVD method.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention relates to a method of cross-linking a flexible substrate such as rubber or resin with an electron beam or an ultraviolet ray and distributing a large number of unreacted carbon on the surface.
A diamond-like carbon film (DLC) is coated on rubber and resin by a method. After the cross-linking reaction, it is more preferable to expose to any plasma of hydrogen or a fluorine-containing gas. This has the effect of covering the surface containing unreacted carbon and protecting unbound carbon from contamination by impurities.

[1. Substrate] The substrate is rubber or resin.
There are many types of rubber, but the present invention is applicable to the following rubbers. (1) Rubber: natural rubber, butyl rubber, ethylene propylene rubber, chloroprene rubber, chlorinated polyethylene rubber,
Epichlorohydrin rubber, acrylic rubber, nitrile rubber, urethane rubber, silicone rubber, fluoro rubber

According to the present invention, a diamond-like carbon film can be coated on a resin. Resins are broadly classified into two types: thermosetting resins and thermoplastic resins. The thermosetting resin to which the present invention is applied is as follows.

(2) Thermosetting resin: phenol / formaldehyde resin, urea resin, melanin / formaldehyde resin, epoxy resin, furan resin, xylene resin, unsaturated polyester resin, silicone resin, diallyl phthalate resin Diamond according to the method of the present invention. The thermoplastic resin that can cover the carbon-like film is as follows.

(3) Thermoplastic resin (a) vinyl type: polyvinyl chloride, polyvinyl butyrate, polyvinyl alcohol, polyvinylidene chloride, polyvinyl acetate, polyvinyl formal, polyvinyl dichloride, chlorinated polyether, (b) Polyester type: polystyrene, styrene-acrylonitrile copolymer, ABS

(C) Polyethylene: polypropylene,
Polyacetal (d) Acrylic: polymethyl methacrylate, modified acrylic (e) Nylon: 6-nylon, 66-nylon, 6
10-nylon, 11-nylon

(F) Cellulose: ethyl cellulose,
Cellulose acetate, propylcellulose, cellulose acetate / butyrate, cellulose nitrate (g) Polycarbonate: phenoxy, polyester (h) Fluororesin: ethylene trifluoride, ethylene tetrafluoride, ethylene tetrafluoride, ethylene hexafluoropropylene, fluorine Vinylidene fluoride, (i) polyurethane

The base material is rubber, resin or the like.
Until now, a hard diamond-like carbon film could not be formed on such a flexible material.

[2. Pretreatment 1: UV irradiation, electron beam irradiation]
The present invention has made it possible by subjecting rubber and resin to appropriate pretreatment. There are two pre-processing. One of the pretreatments is ultraviolet irradiation and electron beam irradiation. This causes the polymer to crosslink. At the same time, the outermost surface contains unbonded surface atoms. When the unbonded atoms remain on the surface, when the diamond-like carbon film is formed thereon, it has an effect of strengthening the adhesion between the carbon film and the rubber or resin so that the carbon film is not easily separated. The formation of unbonded atoms for ultraviolet rays and electron beams enhances the bonding property with the diamond-like carbon film, and as a result, it is possible to coat the rubber-like resin or the resin-like diamond-like carbon film, which has been impossible so far.

[3. Pretreatment 2: plasma treatment] The second of the pretreatment is to use rubber,
Exposing the resin substrate. The second stage of pre-processing is not essential. It can be omitted. When exposed to plasma of fluorine or hydrogen gas, fluorine or hydrogen covers unbonded surface atoms on the outermost surface, so that impurities can be prevented from being attached. Since no impurities are attached, the adhesion to the diamond-like carbon film increases. As the fluorine-containing gas, fluorine (F ₂ ) gas, nitrogen trifluoride (NF ₃ )
Gas, sulfur hexafluoride (SF ₆ ) gas, carbon tetrafluoride (C
F ₄ ) gas, silicon tetrafluoride (SiF ₄ ) gas, silicon hexafluoride (Si ₂ F ₆ ) gas, chlorine trifluoride (ClF)
₃ ) Gas, hydrogen fluoride (HF) gas and the like.

This plasma treatment may be performed a plurality of times using the same kind of plasma or a plurality of times using different kinds of gases.

[4. Diamond-like carbon film formation] After pretreatment, a diamond-like carbon film is formed on rubber or resin by a thin-film forming method. However, since rubber and resin do not withstand high temperatures, a thin-film forming method that can be performed at a relatively low temperature. Must be chosen. As such, the following three methods are possible.

(A) Plasma CVD method (b) Sputtering method (c) Ion plating method

These methods can form a thin film even on a substrate at a relatively low temperature. The filament CVD method, the lamp CVD method, the vapor deposition method and the like are not suitable. Even if the substrate is not actively heated, heat is generated by the collision of plasma or ions, and the temperature is adjusted by cooling the substrate.

There are various types of rubber and resin as described in detail above. Each has a difference in heat resistance. The temperature at which the quality deteriorates varies depending on the type of rubber and resin. The allowable substrate heating temperature is determined according to the physical properties of the object. The substrate is cooled by a cooling device so that the allowable temperature is not exceeded. When performing a plasma treatment as a pretreatment, a plasma CVD method is particularly suitable among the above three thin film forming methods. This is because plasma processing and thin film formation can be performed continuously with the same apparatus.

The gas for forming the diamond-like carbon film comprises a carrier gas and a source gas containing hydrocarbons. Carrier gas: hydrogen gas, inert gas (Ar, Ne, X
e, He, etc.) Raw material gas: methane (CH ₄ ), ethane (C ₂ H ₅ ), propane (C ₃ H ₈ ), butane (C ₄ H ₁₀ ), acetylene (C ₂ H ₂ ), benzene (C ₆ H ₆ )

[5. Uses] Rubbers and resins are used for various uses, but the present invention can be applied to the uses listed below.
Of course, it can be applied to many other fields.

(A) Rubber: Used for wiper blades, valve seats, valve packings, films, tubes, insulating sheets, bushings and the like. (B) Thermoplastic resin: Building materials such as water pipes, building materials, flooring, general household goods such as films, records, nets, kitchenware, toys, decorations, stationery, cases, optical components such as lenses and prisms, It is used for automotive parts such as sealing and packing, mechanical parts such as shock absorbers, gears and bearings.

(C) Thermosetting resin: films, records, nets, buttons, kitchenware, toys, ornaments, stationery, cases, tableware, household goods such as sports goods, insulators, electric parts such as terminals, fuel Used for mechanical parts such as tanks, automobile bodies and bearings.

[6. Properties] Rubber and resin coated with a diamond-like carbon film exhibit the following excellent properties. One is that the coefficient of friction is extremely small. The sliding resistance is much lower than that of rubber or resin. Very good slip. Rubber sticks to a smooth metal or wood surface, but rubber coated with a diamond-like carbon film slips. Not only that. Excellent wear resistance.
Does not wear due to repeated friction. Since the lubricant is not dispersed on the surface, the wear resistance does not decrease even after many years of use.

The most important thing is that the diamond-like carbon film does not peel off from the substrate. Because it is rubber, it can be bent and stretched freely. The diamond-like carbon film does not peel off when bent or extended. This is a surprising property. Since unreacted atoms are generated on the surface by the pretreatment, the carbon of the diamond-like carbon film forms a new chemical bond with the unreacted atoms. This chemical bond firmly links the diamond-like carbon film with rubber and resin. Those without pre-treatment will peel off immediately. The usefulness of the preprocessing proposed by the present invention is clearly seen.

It is more important that the diamond-like carbon film coating does not lose the original flexibility of the substrate. If you push it, it will bend and if you twist it, it will bend. For a member in which rubber has conventionally been used, the diamond-like carbon coated rubber of the present invention can be used as it is. Although the wiper of an automobile has been described as an example, when the rubber of the present invention is used for the wiper, the function of removing water drops is not impaired while the abrasion resistance is excellent.
The service life is significantly extended without wear due to long-term use. It is much better than conventional rubber for wipers whose surface is impregnated with a lubricant.

Since the surface hardness is increased by the diamond-like carbon film, it is possible to prevent the substrate from being damaged. The inherent properties of the diamond-like carbon film, such as high insulation, good light transmission, and high hardness, are maintained even when formed on rubber or resin.

[0042]

FIG. 1 schematically shows an ultraviolet irradiation apparatus used for pretreatment in the present invention. An ultraviolet lamp 2 is provided inside the airtight container 1. The sample 3 is arranged at a position facing the sample 3. Gas is introduced from the gas inlet 4 into the airtight container 1. The inside of the container 1 can be evacuated by the pump 5. Ultraviolet irradiation may be performed in a vacuum state without supplying gas. Alternatively, an inert gas (Ar, Kr, Ne, He) or an active gas (N ₂ , O
₂ ) etc. may be introduced and ultraviolet irradiation may be performed in that atmosphere.

FIG. 2 shows a schematic configuration of an electron beam irradiation apparatus used for pretreatment in the present invention. FIG. 3 shows a state in which a sample such as rubber or resin is pretreated. It is a vertically long device, and includes a DC high-voltage cable 6, a bushing 7, a container containing SF ₆ gas, an acceleration tube 9, a scanning device 10, and the like from above. Further below this is a triangular scanning tube 11 and a gold ring 12. The scanning tube 11 is evacuated. Titanium foil 1 at the bottom
3 is attached. This is necessary to maintain a vacuum inside the scanning tube 11. The electron beam passes through the titanium foil 13 and exits at atmospheric pressure. Atmospheric pressure is filled with nitrogen gas. The sample passes just below the scanning tube 11. Meanwhile, the sample is irradiated with an electron beam.

In FIG. 3, the operation panel 16 performs an operation of irradiating an electron beam. A high DC voltage is supplied from the DC power supply 15 to the electron beam irradiation device through the cable 6. The filament is heated by a direct current to generate electrons. Electrons are drawn out toward the accelerating tube 9 by the difference between the voltages applied in the vertical direction. The accelerator tube has a plurality of electrodes and an insulator, and electrons are accelerated by a DC voltage. The accelerated electron beam is scanned two-dimensionally or one-dimensionally by the scanning device 10.

This is achieved by periodically oscillating the electron beam with an alternating magnetic field. A conveyor 17 is provided immediately below the scanning tube 11 (scanner), and a sample such as rubber or resin is carried by the conveyor 17. The irradiation of the electron beam causes a cross-linking reaction in the sample, and a large number of unbonded atoms appear on the surface. FIG. 3 shows an example of polyethylene. Irradiation causes crosslinking between molecules constituting the fiber. It is a well-known technique to crosslink a resin by irradiating it with an electron beam. In the present invention, a large number of unbonded atoms are generated by an electron beam. This increases the adhesion to the diamond-like carbon film.

The pretreatment 1 may be either ultraviolet light or electron beam. Both may be used in combination. Preprocessing 2
FIG. 4 shows an apparatus for forming a thin film. This is plasma C
It is a VD device. As described above, a diamond-like carbon film can be formed by sputtering or ion plating. In both cases, pay attention to cooling rubber,
A thin film can be formed without deteriorating the resin.
In the case of performing the pretreatment 2 using plasma, using a plasma CVD apparatus is convenient because both the pretreatment 2 and the thin film preparation can be performed by the same apparatus. All the examples are plasma C
A VD device was used.

An exhaust pump 21 is connected to the vacuum chamber 20 through a pressure regulating valve 22 so that gas inside can be extracted from an exhaust port 27. By applying a high frequency between the parallel plate electrodes 23 and 25, a high frequency electric field is formed inside the chamber, and the gas is turned into plasma. Above there is a ground electrode 23. There is a high-frequency electrode 25 below. Both are provided so as to face in parallel. The sample substrate 24 is placed on the high-frequency electrode 25
(Rubber, resin) is placed.

A heater 26 and a cooling device (not shown) are built in the high-frequency electrode 25. Of course, there are also temperature measuring devices such as thermocouples. While measuring the temperature, the sample substrate 24 can be kept at an arbitrary temperature by the heater and the cooling device. Since rubber and resin are targeted, the temperature can be controlled by using only a cooling mechanism without using a heater in many cases.

As the gas, a hydrogen gas and a fluorine-containing gas for plasma treatment, a hydrocarbon gas for forming a thin film, and hydrogen and an inert gas as a carrier gas are required. The gas is introduced from the gas cylinder 28 to the vacuum chamber 20 through the gas inlet 34 via the pressure regulating valve 32 and the mass flow controller (MFC) 33. The MFC 33 controls the gas flow rate accurately.

The high frequency power supply 30 is a matching box 29
, Power is applied to the high-frequency electrode 25 and the ground electrode 23. A matching box is required for impedance matching. When a high frequency is applied between the electrodes, electrons are accelerated by electricity and collide with gas molecules, so that electrons are lost and plasma 35 is formed.

Next, examples and comparative examples will be described. Each sample was a polyethylene sheet and the dimensions were 1 mm
× 100 mm × 100 mm. There are cases from 1st to 10th. Nos. 2 to 9 are examples, and Nos. 1 and 10
The number is a comparative example. The pretreatments 1 and 2 of Nos. 1 to 10 and the thin film forming method are shown in Table 1 in advance.

[0052]

[Table 1]

In Comparative Example 1, a diamond-like carbon film was formed on a polyethylene sheet by a plasma CVD method without any pretreatment. Comparative Example 10 is a substrate sheet itself and a thin film was not formed. Example 2
Has produced a diamond-like carbon film by plasma CVD after irradiating ultraviolet rays. In Example 3, a thin film was formed by plasma CVD after irradiating an electron beam.

In Embodiments 4 and 7, a thin film is formed after ultraviolet irradiation and hydrogen gas plasma treatment. Example 5 and Example 8 show that after ultraviolet irradiation + SF ₆ plasma treatment,
A diamond-like carbon film was formed. In the sixth and ninth embodiments, a diamond-like carbon film is formed after ultraviolet irradiation + hydrogen plasma treatment + SF ₆ plasma treatment.

[A. UV irradiation conditions] Examples 2, 4 to 9
Are all the same. UV intensity 15 mW / cm ² (at λ = 254 nm) Irradiation distance 10 mm Irradiation time 100 sec Irradiation area 200 mm × 200 mm

[B. Electron beam irradiation conditions] Pretreatment conditions of Example 3 Acceleration voltage 200 keV Electron beam current 100 mA Irradiation time 30 sec Scan width 450 mm

[C. Hydrogen Gas Plasma Processing Conditions] The conditions in Examples 4, 6, 7, and 9 are all the same. Pretreatment gas Hydrogen gas (H ₂ ) 100 sccm High frequency power 13.56 MHz 300 W Vacuum degree 0.1 Torr Processing time 10 min

[D. Fluorine Compound Gas Plasma Treatment Conditions] The conditions in Examples 5, 6, 8, and 9 are common. Pretreatment gas Sulfur hexafluoride (SF ₆ ) 100 sccm High frequency power 13.56 MHz 300 W Vacuum degree 0.1 Torr Processing time 10 min

[E. Plasma CVD Thin Film Formation Conditions] These are common to Examples 2 to 9 and Comparative Example 1. Dimensions of high-frequency electrode Φ280 mm Source gas Methane (CH ₄ ) gas 100 sccm High-frequency power 13.56 MHz 300 W Deposition vacuum 0.1 Torr Deposition rate 50 nm / min (500 ° / min) Deposition time 10 min

In C, D, and E, the substrate is heated by the collision of the plasma with the substrate. The temperature of the substrate was kept at about 80 ° C. by a cooling device. The cooling device was controlled so as not to exceed 150 ° C. at the maximum.

[0061]

[Table 2]

The coefficient of friction was determined by moving an aluminum pin to which a load of 10 g was applied at a speed of 20 mm / sec and measuring the resistance. The wear characteristics were measured by moving the diamond pin at a speed of 20 mm / sec while applying a load of 10 g and measuring the wear depth per hour. The ratio of unbonded atoms on the surface of the substrate was measured by an energy loss spectrum analyzer (EELS). With the total number of carbon atoms present on the surface as 100%, the ratio of atoms having unbonded hands (dangling bonds) was determined. The number of unbound carbons increases with ultraviolet and electron beam irradiation. This is strongly linked to the components of the diamond-like carbon film, so that the film does not peel off.

In all the examples, the coefficient of friction is 1 or less. Slip is good. Even if used as a valve seat or packing for many years, the valve stem and valve body will not stick.
It is obvious that the abrasion characteristics are 0.7 or less and the abrasion resistance is excellent. The examples of the present invention are also excellent in adhesion. The rubber is not easily peeled when folded, bent or stretched. The adhesion is particularly high in Examples 6 and 9, probably because hydrogen plasma processing and SF ₆ plasma processing are performed.

[0064]

The present invention has succeeded for the first time in coating a flexible material such as rubber or resin with a diamond-like carbon film as a hard film. Since the bonding between the rubber and the resin and the diamond-like carbon film is enhanced by the pretreatment, the coating does not peel off even when the rubber or the resin is pulled and bent. Moreover, the inherent elasticity of the rubber is hardly impaired. Low sliding resistance due to low coefficient of friction. Good wear resistance. Since it is a hard film, a base material such as rubber can be protected from external impact. An excellent composite material can be provided.

For example, when the present invention is applied to the rubber of a blade of an automobile wiper, the blade has excellent sliding characteristics and does not wear. Long life. The edges are not jagged as with conventional blades. The draining performance does not decrease. The frequency of blade replacement can be reduced. The wiper blade according to the present invention was subjected to 200,000 reciprocating tests. There is no difference between the micrographs before and after the test. The edges are not jagged and there is almost no wear.

For example, when used for a valve seat, wear resistance is increased, so that there is no inconvenience such as fatigue due to use and an increase in opening / closing torque. It can be widely used as packing rubber. In addition, it can be expected to have various uses as building materials and household goods. This is an excellent invention.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an ultraviolet irradiation apparatus used for performing a pretreatment according to the present invention.

FIG. 2 is a schematic front view of an electron beam irradiation apparatus used for performing a pretreatment according to the present invention.

FIG. 3 is a diagram of an electron beam irradiation device, a control panel, and a DC power supply used for performing a pretreatment according to the present invention.

FIG. 4 is a schematic configuration diagram of a plasma CVD apparatus used for forming a diamond-like carbon film by the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Vacuum chamber (confidential container) 2 Ultraviolet lamp 3 Sample 4 Gas inlet 5 Vacuum pump 6 DC high voltage cable 7 Bushing 8 SF ₆ Gas 9 Acceleration tube 10 Scanning device 11 Scanning tube (scanner) 13 Titanium foil 14 Window 15 DC power supply 16 Operation panel 17 Conveyor 20 Vacuum chamber 21 Vacuum pump 22 Pressure control valve 23 Ground electrode 24 Substrate 25 High frequency electrode 26 Heater 27 Exhaust port 28 Gas cylinder 29 Matching box 30 High frequency power supply 32 Pressure control valve 33 Mass flow controller 34 Gas inlet 35 Plasma

Claims (3)

[Claims] 1. A rubber or resin as a base material is irradiated with ultraviolet rays or an electron beam or both to generate unbonded carbon atoms on a surface thereof, and then a hydrocarbon gas is supplied as a raw material to excite the hydrocarbon gas to excite the gas to produce a gas phase reaction. And forming a diamond-like carbon film on the surface of the rubber or resin. 2. The rubber-resin according to claim 1, wherein the rubber-resin after irradiation with ultraviolet rays or electron beams is subjected to a plasma of fluorine-containing gas or hydrogen gas. How to form. 3. A diamond-like carbon film is formed by a plasma CVD method, an ion plating method or a sputtering method while cooling a rubber or resin base material to suppress a rise in temperature. A method for forming a diamond-like carbon film on the rubber or resin described in the above.