JP6020987B2 - Carbon film, polymer product, carbon film coating material manufacturing method, film forming method, and film forming apparatus - Google Patents

Description

  The present invention relates to a carbon film, a polymer product, a carbon film coating material manufacturing method, a film forming method, and a film forming apparatus.

  Plastic and rubber products may require coating to reduce friction. Conventionally, a coating obtained by coating a solid lubricant such as PTFE, graphite, or molybdenum as it is or a coating obtained by mixing them with a resin is often used.

  Carbon films, especially amorphous carbon films such as DLC (diamond-like carbon), have excellent lubricity, wear resistance, chemical stability, and biocompatibility. Have begun to be studied, and some have been put into practical use (for example, Patent Document 1).

  The DLC film can be formed by physical vapor deposition (PVD) or chemical vapor deposition (CVD). For example, in the plasma CVD method, after introducing a source gas into a vacuum chamber, the source gas is activated by high frequency discharge or microwave discharge to form a DLC film on a substrate.

International Publication No. 2007/105428 JP 2005-322416 A

  However, in order to form a DLC film using PVD or CVD, a large vacuum apparatus is required, and there is a problem in that it is inferior in mass productivity and the work shape is limited because it must be a batch process. It was. In addition, since these methods increase the film forming temperature, there is a problem that they are not suitable for forming a film of a polymer material such as plastic or rubber having poor heat resistance.

  Under such circumstances, an atmospheric pressure low temperature plasma generator that can stably generate low temperature plasma under atmospheric pressure and has no limitation on the shape, type and working environment of the substrate to be treated has been developed (for example, Patent Document 2).

  The present invention relates to a carbon film having a low coefficient of friction and having more flexibility and excellent adhesion, a polymer product coated with the carbon film, and a method for producing a carbon film coating material coated with the carbon film. An object is to provide a film forming method and a film forming apparatus.

  As a result of improving the atmospheric pressure low temperature plasma generator of the above type and intensively studying a film forming method, the present inventors have found that a carbon film having excellent adhesion even to a polymer material substrate having poor heat resistance. As a result, the present invention was conceived.

That is, the present invention provides the following means.
(1) In ATR-FTIR using a germanium crystal, the absorption peak intensity appearing at 2800 to 3000 cm ⁻¹ is 0.01 or less, and the absorption peak intensity appearing at 3000 to 3600 cm ⁻¹ is 0.002 or less. An absorption peak intensity appearing at ˜1800 cm ⁻¹ is 0.005 or less.
(2) The intensity ratio (I _D / I _G ) between the peak intensity (I _D ) of the _D band and the peak intensity (I _G ) of the G band measured by Raman scattering spectroscopy is 0.1 or less. The carbon film according to (1), characterized in that
Here, when both the peak of the D band and the peak of the G band are not measured, the intensity ratio (I _D / I _G ) is set to zero.
(3) The carbon film according to any one of (1) and (2), wherein the G band is located on a higher wavenumber side than 1600 cm ⁻¹ .
(4) The proportion of carbon in the atomic composition ratio of carbon, nitrogen, and oxygen measured by X-ray photoelectron spectroscopy (XPS) is 90% or more and 99% or less, and the proportion of oxygen is 1% or more and 10%. The carbon film according to any one of (1) to (3), wherein:
(5) The ratio of hydrogen in the atomic composition ratio of carbon and hydrogen measured by glow discharge emission spectroscopy is 40% or more and 60% or less, wherein any one of (1) to (4) The carbon film described in 1.
(6) The carbon film according to any one of (1) to (5), wherein a friction coefficient with respect to the SUS material is 0.25 or less.
(7) A polymer product comprising the carbon film according to any one of (1) to (6) on at least one surface of a base material made of a polymer material.
(8) The polymer product according to (7), wherein the polymer material is a synthetic resin or rubber.
(9) The polymer product according to any one of (7) and (8), wherein the carbon film has a thickness of 1 μm to 10 μm.
(10) The polymer material product is any one of blade rubber, seal, bearing, roll, bush, mount, belt, tube, and boot, according to any one of (7) to (9) The polymer product described.
(11) A method for producing a carbon film coating material in which a carbon film is coated on a substrate to be treated,
Place the substrate to be treated in a semi-sealed container,
Introducing an inert gas into the hollow part of the plasma generating nozzle comprising an external electrode on the outer peripheral surface of the dielectric cylinder and an internal electrode on the inner peripheral surface of the dielectric cylinder, and the external electrode and the internal electrode Plasma is generated under atmospheric pressure by applying an AC voltage between
In the semi-sealed container, the carbon film source gas is added to the plasma flow emitted from the plasma discharge port of the plasma generating nozzle, and the plasma film is discharged from the discharge port of the semi-closed container, while the carbon film source gas is removed from the substrate. A method for producing a carbon film-covering material, characterized in that the substrate is sprayed onto the material to coat the substrate to be treated with a carbon film.
(12) The method for producing a carbon film coating material according to (11), wherein the inert gas is argon gas, helium gas, nitrogen gas, or a mixed gas thereof.
(13) The carbon film raw material gas according to any one of (11) and (12), wherein the carbon film raw material gas includes hydrocarbon, aromatic, alcohol, ether, or a mixed gas thereof. Method.
(14) The method for producing a carbon film covering material according to any one of (11) to (13), wherein the carbon film source gas is sent using an inert gas as a medium.
(15) The method for producing a carbon film coating material according to any one of (11) to (14), wherein the substrate to be treated is a polymer material.
(16) A film forming method for forming a film on a substrate to be processed,
Place the substrate to be treated in a semi-sealed container,
Introducing an inert gas into the hollow part of the plasma generating nozzle comprising an external electrode on the outer peripheral surface of the dielectric cylinder and an internal electrode on the inner peripheral surface of the dielectric cylinder, and the external electrode and the internal electrode Plasma is generated under atmospheric pressure by applying an AC voltage between
In the semi-sealed container, the source gas is added to the plasma flow discharged from the plasma discharge port of the plasma generating nozzle, and the source gas is sprayed on the substrate to be processed while discharging the plasma from the discharge port of the semi-closed container. A film forming method characterized by forming a film.
(17) A plasma generating nozzle comprising an external electrode on the outer peripheral surface of the dielectric cylinder and an internal electrode in a tubular shape on the inner peripheral surface of the dielectric cylinder;
A semi-sealed container having a substrate to be treated and having an upper opening for introducing plasma and an outlet for discharging plasma;
A source gas supply pipe connected to the semi-sealed container;
A film forming apparatus comprising:
(18) The film forming apparatus according to (17), wherein the surface of the dielectric has a void structure at least in the vicinity of the plasma discharge port of the internal electrode.
(19) The film forming apparatus according to any one of (17) and (18), wherein an inner peripheral surface of the internal electrode is covered with a dielectric film.
(20) The tip of the plasma generating nozzle is covered with a conductor mesh, and the conductor mesh is connected to an external ground electrode. (17) The composition described in any one of (19), Membrane device.

  According to the present invention, a carbon film having a low friction coefficient and more flexible than before, and having excellent adhesion, a polymer product coated with the carbon film, and a carbon film coating material coated with the carbon film. A manufacturing method, a film forming method, and a film forming apparatus can be provided.

It is a schematic diagram of an example of the film-forming apparatus which is embodiment of this invention. It is an expansion perspective view of a plasma generation nozzle, (a) 3 layer structure, (b) 4 layer structure. Three examples of internal electrodes of the present invention are shown. Four examples of the plasma generating nozzle of this invention are shown. (A)-(d) shows the result of having performed the experiment of spark generation about each structure of FIG. 4 (a)-(d). (A)-(d) shows the result of having measured Ar plasma luminescence intensity using emission spectroscopic analysis about each composition of Drawing 4 (a)-(d). (A) And (b) shows the other example of the film-forming apparatus of this invention. It is a graph which shows the result measured by ATR-FTIR using a germanium crystal about the carbon film formed by the film-forming method of the present invention, and a comparative example, (a) comparative example, (b) carbon film of the present invention ( Examples 1 and 2). It is a graph which shows the result measured by the Raman scattering spectroscopy about the carbon film formed into a film by the film-forming method of this invention, and the commercially available carbon film (Genius Coat F (brand name) by Nippon ITF Co., Ltd.). It is a table | surface which shows the result measured by the X ray photoelectron spectroscopy (XPS) about the carbon film formed by the film-forming method of this invention, a comparative example, and a commercial item. It is a table | surface which shows the result measured by the glow discharge emission spectroscopy (GD-OES) about the carbon film formed into a film by the film-forming method of this invention. It is a table | surface which shows the result of having measured the friction coefficient about the carbon film formed by the film-forming method of this invention, a comparative example, a base material (EPDM), a commercial item, and a graphite coat. It is a graph which shows the result of having measured the friction behavior about the carbon film formed by the film-forming method of this invention, a comparative example, a base material (EPDM), a commercial item, and a graphite coat. It is a schematic diagram of the apparatus which measured the friction coefficient.

  Hereinafter, a configuration of a carbon film, a polymer product, a carbon film coating material manufacturing method, a film forming method, and a film forming apparatus according to embodiments of the present invention will be described with reference to the drawings. In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. . In addition, the materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not limited to them, and can be appropriately changed and implemented without changing the gist thereof.

(Deposition system)
In FIG. 1, an example of the film-forming apparatus which is embodiment of this invention is shown. FIGS. 2A and 2B are enlarged perspective views of the plasma generating nozzle 1.
A film forming apparatus 100 shown in FIG. 1 includes a plasma generating nozzle 1 having an outer electrode 13 on an outer peripheral surface 12a of a dielectric cylinder 12 and an inner electrode 14 on an inner peripheral surface 12b of the dielectric cylinder, respectively. A substrate 10 to be treated is disposed and connected to a semi-sealed container 2 having an upper opening 2a for introducing plasma and a discharge port 2b for discharging plasma, and a side wall (side surface) 2c of the semi-sealed container 2 The raw material gas supply pipe 3 is provided.

  A film forming apparatus according to an embodiment of the present invention is a film forming apparatus using so-called creeping discharge type atmospheric pressure low-temperature plasma generation, and generates a plasma having a low temperature (for example, 80 ° C. or less). The film can be formed by activating the raw material.

  The plasma generating nozzle 1 shown in FIG. 1 has a triple tube (three layers) structure of a dielectric cylinder 12, an external electrode 13, and an internal electrode 14. The internal electrode, the dielectric cylinder, and the external electrode constituting the plasma generating nozzle 1 shown in FIG. 1 are all cylindrical, but are not limited to a cylindrical (circular tube) shape, but a rectangular tube (square tube) shape or the like. There may be.

FIG. 2A is an enlarged perspective view of the plasma generating nozzle 1 in the film forming apparatus shown in FIG.
FIG. 2B is another example of the plasma generating nozzle 1, whereas FIG. 2A has a triple tube (three-layer) structure, whereas FIG. It is a quadruple tube (four layers) structure further including a dielectric tube (dielectric film) 15 on the peripheral surface. As will be described later, the effect of suppressing sparks can be obtained by covering the inner peripheral surface of the internal electrode 14 with a dielectric tube (dielectric film) 15 so that the internal electrode 14 does not come into contact with the inert gas.

The plasma generating nozzle (plasma torch) 1 includes a hollow portion 1a and a plasma discharge port 1b, introduces an inert gas into the hollow portion 1a, and applies an AC voltage between the external electrode and the internal electrode. The inert gas plasma is generated and discharged from the plasma discharge port 1b.
As the inert gas, for example, argon gas, helium gas, nitrogen gas, or a mixed gas thereof can be used.

Of the two electrodes (external electrode 13 and internal electrode 14), the internal electrode 14 is connected to the high voltage side, and the external electrode 13 is connected to the ground.
For example, a pulse waveform power is supplied between the two electrodes, and an AC voltage having a frequency of 10 kHz or more and 5 kV or more is applied.

The internal electrode 14 preferably has a gap structure 14a (see FIG. 3) so that the surface 12a of the dielectric cylinder 12 is exposed at least in the vicinity of the plasma discharge port 1b. The gap structure 14a is not limited. For example, as shown in FIG. 3, a mesh or punching can be used. Moreover, it can also be set as a coil shape.
Since the plasma is generated along the outer periphery of the contact surface between the internal electrode (high voltage side electrode) 14 and the dielectric cylinder 12, the plasma generation amount increases as the contact outer periphery between the dielectric cylinder 12 and the internal electrode 14 increases. Therefore, by configuring the internal electrode 14 to have a gap structure 14a such as a mesh or a punching plate, the outer periphery of the dielectric cylinder 12 can be gained (that is, the internal electrode 14 and the dielectric cylinder). This is because it is possible to increase the contact boundary length with 12 and increase the plasma generation amount.

The material of the dielectric cylinder 12 is not limited. For example, silicone, dielectric ceramics, or the like can be used.
The material of the external electrode 13 and the internal electrode 14 is not limited, but for example, a metal such as copper, iron, stainless steel, aluminum, or nickel can be used.

4A to 4D show examples of the plasma generating nozzle 1. Each of FIGS. 5A to 5D shows a result of an experiment of spark generation in each of FIGS. 4A to 4D. 6A to 6D show the results of measuring the plasma emission intensity in each case of FIGS. 4A to 4D by using emission spectroscopic analysis. is there. 5 (c) and 5 (d) and FIGS. 6 (c) and 6 (d), the case where only Ar and the mixed gas of Ar and N ₂ are used as the inert gas. Show.

In the spark generation experiment of FIG. 5, the Ar gas flow rate is 6 L / min, the Ar / N ₂ mixed gas is 6 L / min Ar gas flow rate, the N ₂ gas flow rate is 0.1 L / min, the AC voltage is ± 8 kV, The test was performed under the conditions of a frequency of 20 kHz and a duty of 50%.
As shown in FIGS. 5 (a) and 5 (b), sparks are generated in both FIGS. 4 (a) and 4 (b), but the inner circumference of the internal electrode 14 is larger than that in FIG. 4 (a). In the case of FIG. 4B where the surface was covered with a dielectric tube, the occurrence of sparks was suppressed.
As shown in FIGS. 5 (c) and 5 (d), no spark occurred in either of FIGS. 4 (c) and 4 (d).

The Ar plasma emission intensity in FIG. 6 was also measured under the same conditions as the spark generation experiment in FIG.
As shown in FIG. 6C and FIG. 6D, when the metal mesh is provided, the plasma emission intensity is high.

The structure of the plasma generating nozzle 1 shown in FIGS. 4A to 4D will be described in detail.
The example of the plasma generating nozzle 1 in FIG. 4A has a triple tube structure of a dielectric cylinder 12, an external electrode 13, and an internal electrode 14, and the dielectric cylinder 12 is covered by the external electrode 13 and the internal electrode 14 at the tip 1 A. This is an unstructured configuration. Specifically, the dielectric cylinder 12 has an inner diameter of 8 mm and an outer diameter of 12 mm, the inner electrode 14 has an inner diameter of 7 mm and an outer diameter of 8 mm, the outer electrode 13 has an inner diameter of 12 mm, a width of 20 mm, and the tip not covered by the outer electrode and the inner electrode. The length of the part 1A is 10 mm.
In the example of the plasma generating nozzle 1 of FIG. 4B, the inner peripheral surface of the internal electrode 14 is covered with a dielectric tube 15 in the triple tube structure of the dielectric cylinder 12, the external electrode 13, and the internal electrode 14, The distal end portion 1 </ b> A has a configuration in which the dielectric cylinder 12 is not covered with the external electrode 13 and the internal electrode 14. Specifically, the dielectric cylinder has an inner diameter of 9 mm and an outer diameter of 12 mm, the inner electrode has an inner diameter of 8 mm and an outer diameter of 9 mm, the outer electrode has an inner diameter of 12 mm and a width of 20 mm, the dielectric tube has an inner diameter of 6 mm, an outer diameter of 8 mm, the outer electrode and The length of the tip portion not covered with the internal electrode is 10 mm.
In the example of the plasma generating nozzle 1 in FIG. 4C, the inner peripheral surface of the internal electrode 14 is further covered with a dielectric tube 15 in the triple tube structure of the dielectric cylinder 12, the external electrode 13, and the internal electrode 14. The tip portion 1A has a configuration in which the dielectric cylinder 12 is not covered by the external electrode 13 and the internal electrode 14, but the portion (including the plasma discharge port) is covered by a metal mesh (conductor mesh) 16. Specifically, the dielectric cylinder has an inner diameter of 9 mm and an outer diameter of 12 mm, the inner electrode has an inner diameter of 8 mm and an outer diameter of 9 mm, the outer electrode has an inner diameter of 12 mm and a width of 20 mm, the dielectric tube has an inner diameter of 6 mm, an outer diameter of 8 mm, the outer electrode and The length of the tip portion not covered with the internal electrode is 10 mm, and the metal mesh is 1 mm.
The example of the plasma generating nozzle 1 shown in FIG. 4D includes a dielectric cylinder 12, an internal electrode 14, and a dielectric tube 15 on the inner peripheral surface of the internal electrode 14. Although the dielectric cylinder 12 is not covered, the portion (including the plasma discharge port) and a part of the outer side of the dielectric cylinder 12 are covered with a metal mesh 16, and the tip of the dielectric tube 15 is further covered. The inner peripheral surface of the part is covered with the glass tube 17. In this configuration, the metal mesh also functions as an external electrode. Specifically, the dielectric cylinder has an inner diameter of 9 mm and an outer diameter of 12 mm, the inner electrode has an inner diameter of 8 mm and an outer diameter of 9 mm, the dielectric tube has an inner diameter of 6 mm and an outer diameter of 8 mm, and the tip not covered by the outer electrode and the inner electrode The length is 10 mm, the metal mesh is 1 mm mesh, the glass tube has an inner diameter of 5 mm and an outer diameter of 6 mm.

  As shown in FIGS. 4B to 4D, the inner peripheral surface of the internal electrode 14 may be covered with a dielectric film. When the high-pressure internal electrode 14 directly touches an inert gas (Ar, He, nitrogen, or a mixed gas thereof) passing through the hollow portion 1a of the plasma generating nozzle 1, a base material with relatively high conductivity (coating base material) In some cases, sparks are generated and uniform film formation may be hindered. In such a case, as shown in FIGS. 5B to 5D, the inner peripheral surface of the internal electrode 14 is covered with a dielectric film so that the internal electrode 14 does not come into contact with the inert gas, thereby suppressing the spark. The effect is obtained.

As shown in FIGS. 4C and 4D, the tip portion 1A of the plasma generating nozzle 1 may be covered with a conductor mesh, and this conductor mesh may be connected to the external ground electrode.
By covering the plasma discharge port 1b with a mesh-like ground electrode (conductor mesh), as shown in FIGS. 5 (c) and 5 (d), the spark to the base material (coating base material) can be prevented by the mesh. Further, as shown in FIG. 6C and FIG. 6D, stronger plasma can be generated.

A semi-hermetic container 2 shown in FIG. 1 includes an upper part 2A and a lower part 2B.
The upper part 2A has a plasma introduction hole 2d penetrating vertically at the center (the plasma inlet of the plasma introduction hole 2d on the upper surface of the upper part 2A is the upper opening 2a, and the plasma introduction hole on the lower surface of the upper part 2A. 2d plasma outlet is the source gas discharge port 2Aa), and the source gas supply port 2Ac to which the source gas supply pipe 3 is connected is provided on the side surface.
The lower part 2B is formed in a bottomed cylindrical shape whose upper part is opened, and the substrate to be processed 10 is placed on the bottom part 2Ba. Since the diameter (horizontal direction) of the upper open end is formed larger than the diameter of the upper part 2A, a gap is formed in a state where the upper part 2A and the lower part 2B are overlapped, and the gap constitutes the plasma discharge port 2b. To do.
In the drawing, the plasma in the plasma introduction hole 2d and the lower part 2B from the upper opening 2a is schematically shown in a hatch pattern.

The semi-hermetic container 2 functions as a film forming chamber for forming a film on the surface of the substrate 10 to be processed. In the semi-sealed container 2, plasma is introduced from the upper opening 2a, the inside of the semi-sealed container 2 is pressurized by the plasma flow, and the gas in the semi-sealed container 2 is continuously discharged to the outside from the discharge port 2b while being stirred. Is done. For this reason, it can prevent that atmospheric air (oxygen) touches the substrate 10 to be processed.
By having such a structure that blocks atmospheric air (especially, blocks oxygen), the carbon film and the carbon film coating material of the present invention can be produced.
The semi-sealed container of the present invention is a container having a semi-sealed structure that has a discharge port for discharging plasma, but can perform film formation while blocking external atmospheric air. If it is such a container, there is no restriction | limiting in the structure.

  The outer wall 2Ab of the upper part 2A of the semi-hermetic container 2 is located on the inner side of the inner wall 2Bb of the lower part 2B and has a structure overlapping each other. The discharge port 2b for discharging the plasma is composed of continuous or a plurality of holes, and the total cross-sectional area of the discharge port 2b is equal to or smaller than the inner diameter cross-sectional area of the plasma generating nozzle 1. After the plasma flow discharged from the torch is sprayed on the base material, it flows concentrically outward from the center, rises along the inner wall 2Bb of the lower part 2B, and is discharged from the discharge port 2b installed on the upper part. To be discharged. The semi-enclosed container 2 has a semi-enclosed structure that promotes the flow of the plasma flow discharged to the outside along the inner wall of the semi-enclosed container via the substrate surface.

The source gas supply pipe 3 is connected to the semi-sealed container 2 (the side surface in the example shown in FIG. 1) in order to form a film on the surface of the substrate to be processed 10 in the semi-sealed container 2, and the source gas is It is configured to be sent to the vicinity of the plasma discharge port 1b of the plasma generation nozzle 1 (downstream of the plasma generation location).
When the source gas and the inert gas are passed through the inside of the plasma generating nozzle 1, active species generated from the source gas are deposited inside the plasma generating nozzle 1, and stable performance cannot be obtained. It was. On the other hand, in the present invention, since the source gas supply pipe 3 is connected to the semi-sealed container 2 and the source gas does not pass through the inside of the plasma generation nozzle 1, the active species generated from the source gas is the plasma generation nozzle 1. Without depositing inside, a high quality film can be formed efficiently using stable plasma generation. Moreover, the maintainability of the plasma generating nozzle 1 is improved.

  Described below are examples of the dimensions of the film forming apparatus. The inner diameter of the dielectric cylinder 12 is 6 mm, the outer diameter is 9 mm, the inner electrode 14 is 4 mm, the outer diameter is 6 mm, the outer electrode 13 is 9 mm, the width (length direction) is 12 mm, and the half. The outer diameter of the upper part 2A of the closed container 2 is 41 mm, the inner diameter is 9 mm, the height (thickness) is 10 mm, the inner diameter of the lower part 2B is 43 mm, and the irradiation distance (distance from the source gas discharge port 2Aa to the bottom part 2Ba) is 10 mm.

7A and 7B show another example of the film forming apparatus of the present invention.
FIG. 7A shows a configuration in which two pairs of plasma generation nozzles 1 and source gas supply pipes 3 are provided. Depending on the film forming apparatus having this configuration, the both surfaces of the base material can be formed in pairs.
FIG. 7B shows a configuration in which four pairs of plasma generation nozzles 1 and source gas supply pipes 3 are provided. Depending on the film forming apparatus having this configuration, the four surfaces of the base material can be formed in pairs.

(Film formation method)
In the film forming method of the present invention, a substrate to be treated is disposed in a semi-sealed container, and an external electrode is provided on the outer peripheral surface of the dielectric cylinder, and an inner electrode is provided on the inner peripheral surface of the dielectric cylinder in a tubular shape. An inert gas such as argon gas, helium gas, nitrogen gas or a mixed gas thereof is introduced into the hollow portion of the plasma generating nozzle, and an AC voltage is applied between the external electrode and the internal electrode to reduce the atmospheric pressure. In the semi-enclosed container, the source gas is added to the plasma flow discharged from the plasma discharge port of the plasma generation nozzle, and the source gas is processed while discharging the plasma from the semi-enclosed container discharge port. A film is formed by spraying on a substrate.

  When the source gas is added to the plasma flow, the source gas may be sent alone, or an inert gas may be sent as a medium.

  There is no restriction | limiting in a to-be-processed base material, The base material which consists of materials with poor heat resistance, for example, a polymeric material, can also be used.

(Method for producing carbon film coating material)
In the method for producing a carbon film coating material according to the present invention, a substrate to be treated is disposed in a semi-sealed container, and an external electrode is formed on the outer peripheral surface of the dielectric cylinder, and an internal electrode is formed on the inner peripheral surface of the dielectric cylinder. Introducing an inert gas into the hollow part of the plasma generating nozzle prepared in the above, and generating an plasma under atmospheric pressure by applying an AC voltage between the external electrode and the internal electrode, in a semi-sealed container The carbon film source gas is added to the plasma flow discharged from the plasma discharge port of the plasma generating nozzle, and the carbon film source gas is sprayed onto the substrate to be processed while discharging the plasma from the discharge port of the semi-sealed container. The substrate is coated with a carbon film.

As the carbon film source gas, a gas containing hydrocarbon, aromatic, alcohol, ether, or a mixed gas thereof can be used.
A hydrocarbon gas that is a gas at normal temperature, such as acetylene or methane, can be directly fed, and a vapor of aromatic, alcohol, hydrocarbon, etc. that is liquid at normal temperature can be converted into argon gas, helium gas, nitrogen gas or a mixture of these gases. Such an inert gas can be fed as a medium.

  When the source gas is added to the plasma flow, the source gas may be sent alone, or an inert gas may be sent as a medium.

  There is no restriction | limiting in a to-be-processed base material, The base material which consists of materials with poor heat resistance, for example, a polymeric material, can also be used.

(Carbon film)
In the ATR-FTIR using germanium crystals, the carbon film of the present invention has an absorption peak intensity appearing at 2800 to 3000 cm ⁻¹ of 0.01 or less and an absorption peak intensity appearing at 3000 to 3600 cm ⁻¹ of 0.002 or less. The absorption peak intensity appearing at 1500-1800 cm ⁻¹ is 0.005 or less.

Here, the absorption peak appearing at 2800 to 3000 cm ⁻¹ is a peak due to hydrocarbons, and the absorption peak appearing at 3000 to 3600 cm ⁻¹ is a peak due to hydroxyl groups (OH) and appears at 1500 to 1800 cm ⁻¹ . The absorption peak is a peak due to a double bond between oxygen and carbon.

FIG. 8 is a graph showing the results of ATR-FTIR measurement using a germanium crystal for a carbon film formed by the film forming method of the present invention and a comparative example.
ATR-FTIR was measured using AVATAR370 / Continu μM (manufactured by Thermo Fisher Scientific). Further, Ge crystal (slide ATR) was used as the ATR crystal. The aperture was 100, and the resolution was 4 cm ⁻¹ .
The absorption peak intensity was measured by measuring the peak height from the baseline as shown in FIG.
Table ^1, 3300cm ^{-1, 2900cm -1,} shows an absorption peak intensity at 1700 cm ^-1.

In Example 1, EPDM (ethylene propylene diene rubber) as a base material, Ar gas as an inert gas was 6 L / min, acetylene gas as a raw material gas was 0.05 L / min, AC voltage was ± 8 kV, frequency was 20 kHz, Duty. Is 50%, and the film is formed in a semi-sealed structure (using a semi-sealed container).
Further, Example 2 uses EPDM as a base material, Ar / N ₂ gas as an inert gas, Ar gas at 5.8 L / min, N ₂ gas at 0.2 L / min, and acetylene gas as 0 as a source gas. .05 L / min, AC voltage is ± 8 kV, frequency is 20 kHz, duty is 50%, and the film is formed in a semi-sealed structure (using a semi-sealed container).
In addition, the comparative example is EPDM as the base material, Ar gas as the inert gas 6 L / min, acetylene gas 0.05 L / min as the source gas, AC voltage ± 8 kV, frequency 20 kHz, Duty 50%, This is a case where film formation is performed in an open environment (a semi-sealed structure is not used).

The difference in film formation conditions between Example 1 and Comparative Example is that film formation was performed in a semi-enclosed structure (using a semi-enclosed container) or in an open environment (no semi-enclosed structure was used). That's what it means. The difference in film formation conditions between Example 2 and Comparative Example is that film formation was performed in a semi-enclosed structure (using a semi-enclosed container) or in an open environment (no semi-enclosed structure was used). That is the difference between inert gases.
When film formation is performed in an open environment (no semi-enclosed structure is used), air (oxygen) is taken into the film formation part from the outside, so that active species generated by the plasma are quenched by oxygen. The raw material (acetylene) cannot be properly decomposed, and oxygen reacts with the raw material, so that a film containing a large amount of oxygen is generated.
As a result shown in FIG. 8, in the comparative example, the oxygen-containing structure such as hydrocarbon (C—H), O—H, and C═O in the film increases. On the other hand, in the case of Examples 1 and 2, since the film formation was performed in a semi-enclosed structure, air (oxygen) was prevented from entering the film formation part from the outside, so the raw material (acetylene) was appropriate. Since the raw material does not react with oxygen, the oxygen-containing structure such as hydrocarbon (C—H), O—H, and C═O in the film is reduced.
For this reason, the carbon film of the present invention is mainly characterized by being composed of more C—H (hydrocarbon), and is characterized by flexibility, adhesion and low friction that can follow the deformation of rubber and plastic. It is.

Regarding the surface hardness of Examples 1 and 2, it is difficult to accurately measure the hardness of the hard coating formed on the rubber, so that the film was formed on the glass under the same conditions as the film formation on the rubber (" The measurement was performed with a nanoindenter for the “substrate” using only glass. The measurement was performed using a diamond barcovic indenter. A typical DLC film has a hardness of 10 to 20 GPa.
The hardness of Examples 1 and 2 was 1.3 GPa and 0.8 GPa, respectively. From this result, it was confirmed that the carbon film of the present invention was a softer (softer) film than a general DLC film.

In addition, the carbon film of the present invention has an intensity ratio (I _D / I _G ) between the peak intensity (I _D ) of the _D band and the peak intensity (I _G ) of the G band measured by Raman scattering spectroscopy. .1 or less. In the carbon film of the present invention, the G band is located on the higher wave number side than 1600 cm ⁻¹ .

  Here, the D band is a peak unique to the graphite structure, and the G band is a carbon-carbon double bond in a carbon crystal (not limited to a double bond of a graphite six-membered ring. For example, a double bond of polyacetylene) Is a band that appears.

FIG. 9 shows the result of measuring the carbon film formed by the film forming method of the present invention and the commercially available carbon film (Genius Coat F (trade name) manufactured by Nippon IT Co., Ltd.) by Raman scattering spectroscopy. It is a graph.
Raman scattering spectroscopy was performed using Almega XR (manufactured by Thermo Fisher Scientific). The excitation laser wavelength was 532 nm, the output was 0.1 mW, the aperture was 50 μm pinhole, the OL magnification was × 100, and the analysis time was 1 sec × 16 times.

Amorphous carbon, especially what is called DLC, is characterized by the appearance of two types of peaks, a G band and a shoulder-shaped D band (see Comparative Example 1).
However, in Example 1, although the G band is seen, the D band cannot be confirmed (I _D / I _G ˜0). Moreover, in Example 2, neither G band nor D band is seen. In Example 1, since the graphite-like 6-membered ring structure does not exist, it is considered that the D band resulting from it does not appear. On the other hand, in Example 2, since the amount of hydrogen in the film is large, the baseline is high and the G band and the D band are hidden.
In both Example 1 and Example 2, the fact that the peak of the D band due to the graphite structure is not observed means that the graphite crystal fraction is not present in the carbon film or is extremely present. It shows that there are few. This indicates that the carbon film is different from a normal DLC film.
Therefore, the carbon film of the present invention is characterized by flexibility that can follow deformation of rubber or plastic.
Thus, the fact that a Raman spectrum different from that of normal DLC was obtained was that the film formation was performed in a semi-enclosed structure (using a semi-enclosed container), and the carbon film was performed in an environment where the film formation was opened (semi-enclosed). It shows that the film has characteristics different from those of the carbon film (without using the sealed structure).

  In the carbon film of the present invention, the proportion of carbon in the atomic composition ratio of carbon, nitrogen and oxygen measured by X-ray photoelectron spectroscopy (XPS) is 90% or more and 99% or less, and the proportion of oxygen is 1. % To 10%.

FIG. 10 shows X-ray photoelectrons for carbon films (Examples 1 and 2) formed by the film forming method of the present invention, comparative examples, and commercially available products (Genius Coat F (trade name) manufactured by Nippon IT Co., Ltd.). It is a table | surface which shows the result measured by spectroscopy (XPS).
X-ray photoelectron spectroscopy (XPS) was performed using KRATOS AXIS-NOVA (manufactured by Shimadzu Corporation). Al (monochrome) was used as the X-ray source, and the pretreatment was PAH (polycyclic aromatic hydrocarbon) etching at 8 kV for 3 minutes.

In Example 1, the ratio of carbon in the atomic composition ratio of carbon, nitrogen, and oxygen is 92.57%, and the ratio of oxygen is 7.43%. In Example 2, the ratio of carbon in the atomic composition ratio of carbon, nitrogen, and oxygen is The proportion is 91.67%, the proportion of oxygen is 6.86%, and the comparative example is 52.82% of carbon in the atomic composition ratio of carbon, nitrogen and oxygen, and the proportion of oxygen is 45.03%. The commercially available product has a carbon ratio of 71.04% and an oxygen ratio of 27.47% in the atomic composition ratio of carbon, nitrogen and oxygen.
Thus, Example 1 and Example 2 are comparative examples in which the ratio of carbon in the atomic composition ratio of carbon, nitrogen and oxygen is 90% or more and the ratio of oxygen is 10% or less. Both of the commercial products have a carbon ratio of less than 90% and an oxygen ratio of more than 10%.
When Example 1 and Example 2 are compared with the comparative example, the film formation is performed in a semi-enclosed structure, so that the ratio of carbon is large and the ratio of oxygen is small compared to the case where the film is formed in an open environment. It can be seen that a carbon film can be formed.
Moreover, when Example 1 and Example 2 are compared with a commercially available product, a carbon film having a larger proportion of carbon and a smaller proportion of oxygen than the commercially available product is obtained by performing film formation in a semi-enclosed structure. It can be seen that it can be formed.
For this reason, the carbon film of the present invention is characterized by low friction because it is mainly composed of more C—H (hydrocarbon).

  In the carbon film of the present invention, the proportion of hydrogen in the atomic composition ratio of carbon and hydrogen measured by glow discharge emission spectroscopy is 40% or more and 60% or less.

FIG. 11 is a table showing the results of measuring the carbon film formed by the film forming method of the present invention by glow discharge emission spectroscopy (GD-OES).
Glow discharge emission spectroscopy (GD-OES) was performed using GD-Profiler2 (manufactured by Horiba, Ltd.). The gas pressure was 600 Pa, the RF output was 35 W, the anode diameter was 4 mm, the sputtering gas was Ar, the pulse power supply conditions were 50 Hz, and Duty 0.1.

In Example 1, the proportion of hydrogen in the atomic composition ratio of carbon and hydrogen is 52% and the proportion of carbon is 48%. In Example 2, the proportion of hydrogen in the atomic composition ratio of carbon and hydrogen is 51%, and the proportion of carbon Was 49%.
Thus, in Example 1 and Example 2, the ratio of hydrogen in the atomic composition ratio of carbon and hydrogen was 40% or more and 60% or less.
For this reason, the carbon film of the present invention is mainly characterized by being composed of more C—H (hydrocarbon), and is characterized by flexibility, adhesion and low friction that can follow the deformation of rubber and plastic. It is.

  The carbon film of the present invention has a friction coefficient with respect to the SUS material of 0.25 or less.

FIG. 12 shows carbon films (Examples 1 and 2) formed by the film forming method of the present invention, comparative examples, base material EPDM, commercially available products (Genius Coat F (trade name) manufactured by Nippon IT Co., Ltd.), It is a table | surface which shows the result of having measured the friction coefficient with respect to SUS material about a graphite coat. FIG. 13 shows friction behavior (fluctuation of coefficient of friction with respect to measurement time) for Examples 1 and 2, Comparative Example, base material EPDM, commercially available product (Genius Coat F (trade name) manufactured by Nippon IT Co., Ltd.), and graphite coat. It is a graph which shows the result of having measured.
The coefficient of friction was measured using a pin-on-disk type friction tester schematically shown in FIG. The measurement was performed under the conditions of a stylus of φ10 mm SUS, a friction speed of 4.4 m / min, a load of 980 mN (100 gf), an atmosphere of 25 ° C. and 45% RH.

The average values of the friction coefficients of Examples 1 and 2 were 0.22 and 0.20, respectively. On the other hand, the base material, the comparative example, the commercial product (Genius Coat F (trade name) manufactured by Nippon IT Co., Ltd.), and the graphite coat are 0.95, 0.33, 0.31, and 0.34, respectively. Met.
As described above, Example 1 and Example 2 have a friction coefficient of 0.25 or less with respect to the SUS material, greatly reducing the friction coefficient of the base material, and more than the friction coefficients of the comparative example, the commercial product, and the graphite coat. It was small.

  The friction surface after sliding for 30 minutes under the same conditions as in the friction coefficient measurement test was observed with a scanning electron microscope. In Examples 1 and 2, no peeling or abrasion was observed, but in the comparative example, the coating was worn away. From this result, it was confirmed that the carbon film of the present invention had higher adhesion and lower friction than the comparative example.

  As shown in FIG. 13, it was found that the carbon films (Examples 1 and 2) formed by the film forming method of the present invention had the smallest variation in the friction coefficient and could maintain a stable friction coefficient.

(Polymer product)
The polymer product of the present invention comprises the carbon film of the present invention on at least one surface of a base material made of a polymer material. Therefore, the polymer product of the present invention has low friction and high adhesion of the carbon film, so that the carbon film is difficult to peel off.
The film thickness of the carbon film can be 1 μm or more and 10 μm or less. This is because if the thickness is less than 1 μm, the friction reducing effect is small and the wear resistance cannot be expected, and if it exceeds 10 μm, the flexibility of the substrate is impaired.
Examples of the polymer material of the polymer product of the present invention include synthetic resin and rubber.
Examples of the polymer product of the present invention include blade rubber, seal, bearing, roll, bush, mount, belt, tube and boot.

DESCRIPTION OF SYMBOLS 1 Plasma generating nozzle 1a Hollow part 2 Semi-sealed container 2a Upper opening 2b Outlet 2c Side wall 3 Raw material gas supply pipe 10 Base material 12 Dielectric cylinder 13 External electrode 14 Internal electrode 14a Void structure 15 Dielectric pipe 16 Metal mesh ( Conductor mesh)
100 Deposition system

Claims (19)

In ATR-FTIR using germanium crystals, the absorption peak intensity appearing at 2800 to 3000 cm ⁻¹ is 0.01 or less, the absorption peak intensity appearing at 3000 to 3600 cm ⁻¹ is 0.002 or less, and 1500 to 1800 cm ^{−. The} absorption peak intensity appearing in ¹ is 0.005 or less,
The proportion of carbon in the atomic composition ratio of carbon, nitrogen and oxygen measured by X-ray photoelectron spectroscopy (XPS) is 90% or more and 99% or less, and the proportion of oxygen is 1% or more and 10% or less. A carbon film characterized by that. The intensity ratio (I _D / I _G ) between the peak intensity (I _D ) of the _D band and the peak intensity (I _G ) of the G band, measured by Raman scattering spectroscopy, is 0.1 or less. The carbon film according to claim 1. The carbon film according to claim 1, wherein the G band is located at a wave number of 1600 cm ⁻¹ .   The carbon film according to any one of claims 1 to 3, wherein a ratio of hydrogen in an atomic composition ratio of carbon and hydrogen, measured by glow discharge emission spectroscopy, is 40% or more and 60% or less. .   The carbon film according to claim 1, wherein a friction coefficient with respect to the SUS material is 0.25 or less.   A polymer product comprising the carbon film according to any one of claims 1 to 5 on at least one surface of a base material made of a polymer material.   The polymer product according to claim 6, wherein the polymer material is a synthetic resin or rubber.   The polymer product according to claim 6, wherein the carbon film has a thickness of 1 μm to 10 μm.   The polymer product according to any one of claims 6 to 8, wherein the polymer material product is any one of a blade rubber, a seal, a bearing, a roll, a bush, a mount, a belt, a tube, and a boot. . A method for producing a carbon film coating material in which the carbon film according to any one of claims 1 to 5 is coated on a substrate to be treated,
Place the substrate to be treated in a semi-sealed container,
Introducing an inert gas into the hollow part of the plasma generating nozzle comprising an external electrode on the outer peripheral surface of the dielectric cylinder and an internal electrode on the inner peripheral surface of the dielectric cylinder, and the external electrode and the internal electrode Plasma is generated under atmospheric pressure by applying an AC voltage between
In the semi-sealed container, the carbon film source gas is added to the plasma flow emitted from the plasma discharge port of the plasma generating nozzle, and the plasma film is discharged from the discharge port of the semi-closed container, while the carbon film source gas is removed from the substrate to be treated. A method for producing a carbon film-covering material, characterized in that the substrate is sprayed onto the material to coat the substrate to be treated with a carbon film.   The method of manufacturing a carbon film coating material according to claim 10, wherein the inert gas is argon gas, helium gas, nitrogen gas, or a mixed gas thereof.   The method for producing a carbon film coating material according to claim 10, wherein the carbon film source gas contains hydrocarbon, aromatic, alcohol, ether, or a mixed gas thereof.   The method for producing a carbon film coating material according to any one of claims 10 to 12, wherein the carbon film source gas is fed using an inert gas as a medium.   The method for producing a carbon film coating material according to any one of claims 10 to 13, wherein the substrate to be treated is a polymer material. A film forming method for forming the carbon film according to any one of claims 1 to 5 on a substrate to be processed,
Place the substrate to be treated in a semi-sealed container,
Introducing an inert gas into the hollow part of the plasma generating nozzle comprising an external electrode on the outer peripheral surface of the dielectric cylinder and an internal electrode on the inner peripheral surface of the dielectric cylinder, and the external electrode and the internal electrode Plasma is generated under atmospheric pressure by applying an AC voltage between
In the semi-sealed container, the source gas is added to the plasma flow discharged from the plasma discharge port of the plasma generating nozzle, and the source gas is sprayed on the substrate to be processed while discharging the plasma from the discharge port of the semi-closed container. A film forming method characterized by forming a film. A film forming apparatus for forming the carbon film according to any one of claims 1 to 5 on a substrate to be processed,
A plasma generating nozzle comprising an external electrode on the outer peripheral surface of the dielectric cylinder and an internal electrode on the inner peripheral surface of the dielectric cylinder, respectively;
A semi-sealed container having a substrate to be treated and having an upper opening for introducing plasma and an outlet for discharging plasma;
A source gas supply pipe connected to the semi-sealed container;
With
The upper opening is provided in a central portion of the semi-sealed container, and the discharge port is disposed so as to face the outside of the central portion so as to surround the central portion. Wherein the internal electrode film forming apparatus of claim 16, wherein the portion in the vicinity of at least the plasma discharge opening is a sky gap structure.   18. The film forming apparatus according to claim 16, wherein an inner peripheral surface of the internal electrode is covered with a dielectric film.   The film forming apparatus according to any one of claims 16 to 18, wherein a tip portion of the plasma generation nozzle is covered with a conductor mesh, and the conductor mesh is connected to an external ground electrode.

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