JPH0280571A - Member coated with carbon film and its formation - Google Patents

Abstract

PURPOSE:To coat the surface of a light-transmissive member with a smooth carbonaceous light-transmissive film without generating static electricity and on which dust is not deposited by forming a hard light-transmissive carbonaceous film having high electric resistivity on the surface of an org. light- transmissive member to be weathered by plasma CVD. CONSTITUTION:Many polyester-resin light-transmissive org. members 1 such as the wind shield and window for automobiles, motorcyces, aircraft, etc., are placed in a reaction vessel 7, electrodes 3-1 and 3-2 are arranged at the upper and lower parts and plural electrodes 13-1 to 13-n between the members 1, a high-frequency voltage is impressed, Agamma 31 as the carrier gas, gaseous hydrocarbons 32 such as methane as the reactive gas, gaseous carbon fluoride 33 as the gaseous additive, and gaseous O2 34 for etching are supplied from a gas system 30. Consequently, high-frequency plasma is produced between the electrodes, the reactive gas is decomposed and ionized, and a hard carbon- based coating film having 1X10<6>-5X10<12>OMEGAcm electric resistivity and light transmittivity is formed on the member 1. By this method, a light-transmissive carbonaceous film having excellent wear resistance, without generating static electricity and on which dust is hardly deposited is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention applies to windows such as front windshields of vehicles, motorcycles, bicycles, ships, aircraft, etc., which are exposed to wind and rain and are subject to wind protection. , the surface of a translucent organic member is covered with carbon or a protective coating mainly composed of carbon. It also improves abrasion resistance, prevents the adhesion of lumps, and prevents the generation of static electricity.

In the present invention, such a thin film is made of carbon or a coating mainly composed of carbon, which is transparent in the visible region and has sufficient hardness, as a wear-preventing protective film. In particular, this protective film can be closely attached to organic substances, has an electrical resistivity of 1 x 106 to 5 x 10'' Ωcm, prevents the generation of static electricity, and has a smooth surface to prevent lumps. It prevents adhesion to cancer.

The present invention aims to form a carbon film or a film containing carbon as a main component on windows such as windshields, side glasses, rear windows, etc. by plasma CVD.

"Prior Art" Generally, in the plasma CVD method, a method of forming a film in a planar shape on a conductive substrate having a flat surface is considered to be industrially effective. Furthermore, a method is also known in which a film is formed using a plasma CVD method while also producing a sputtering effect. Regarding carbon film coating, which is a typical example, the patent application filed by the present inventor is entitled "Composite with Carbon Film and Method for Preparing the Same J" (Japanese Patent Application No. 56-1469)
36 (filed on September 17, 1982) is known.

However, since these are conductive substrates with a substrate placed on one electrode (cathode side) of a parallel plate type using only a pair of electrodes, a carbon film is formed on the top surface of the flat surface using self-generated self-bias. This is a method of forming a film.

``Conventional Problems'' However, in the conventional method of forming a film while producing a sputtering effect, it is not possible to form a film on a curved substrate such as a windshield, especially a car or motorcycle, or a window of a house. For this reason, there has been a need for a method of forming films on a large number of members at once in a large volume space. The present invention has been made for this purpose.

"Means to Solve the Problem" The present invention is directed to the front windshield of automobiles, motorcycles, bicycles, ships, aircrafts, etc., which are exposed to the wind and rain, and which are exposed to the wind and wind, and other members having surfaces of transparent organic materials. In addition, carbon or a film containing carbon as a main component is provided as a protective film. This coating has a specific resistance of 1 x lo6 to 5 x 10" Ωcm, which prevents the generation of static electricity due to friction with chips (generally insulating or mineral), and also prevents dust from adhering to the surface and preventing the light-transmitting surface from being damaged by chips. This prevents devitrification or turbidity due to the occurrence of minute scratches, and maintains a bright translucent surface at all times.

The present invention provides that, as a protective film for this purpose, carbon or a film mainly composed of carbon, which has a specific resistance of 600 to 6000 Kg/co+2 in terms of Vickers hardness and is produced by plasma polymerization or CVD, can be closely adhered onto an organic substance. Based on findings.

In the present invention, for such plasma polymerization or plasma CVD, a first pair of electrodes (first and second electrodes) are arranged at one end and the other end of a reaction space spaced apart from each other. Furthermore, a second
A pair of electrodes (third and fourth electrodes) are provided, and a substrate or member having a surface to be formed is placed therebetween using a holder (20) for the substrate or member. This holder is connected to the reaction vessel at ground level via a capacitor (19). A first alternating voltage is applied between the pair of electrodes to turn the reactive gas into plasma. High frequency voltages having phases different from each other by 1800 or 06 with respect to ground are applied from respective high frequency power sources to each electrode, and alternating voltages which are symmetrical or in phase with each other are applied. As a result, substantially one high-frequency alternating voltage is applied within the frame structure to induce a high-frequency plasma for completely decomposing and ionizing the reactive gas. Furthermore, the other end of each high frequency power source is grounded. Further, a second pair of electrodes is provided with the base body or member sandwiched therebetween, and a second alternating voltage is applied thereto. Then, ions accelerated on the one electrode side by the second alternating voltage sputter on the formation surface of the member and form a strong film on the formation surface. At this time, because it is in plasma, even if the member is insulating, the unnecessary charge passes through the positive sheath on this surface and reaches the opposite surface, and passes through the plasma atmosphere on the opposite surface to the other of the second pair of electrodes. Can conduct current. Thus, even if the substrate or member is insulating, a second pair of electrodes is provided between it and the frequency is lowered so that ions can reach from one electrode to the other in half a cycle. This method attempts to form a thin film on this insulating substrate or member while producing a sputtering effect by controlling the reaction pressure and frequency.

The first alternating voltage is set to a frequency of 1 to 50 MHz, at which plasma glow discharge of the reactive gas is likely to occur, and the second alternating voltage is set to a frequency of 10 Hz to 100 KHz, which applies kinetic energy to the reactive gas to give a sputtering effect on the surface to be formed. Each is applied as a frequency by controlling its output and frequency independently. The pair of electrodes for generating the second alternating voltage are each provided with an independent power source, and the voltages are applied with their phases shifted by 180°.

The phase of the power supply was set to the common ground level. Also this second
Due to the alternating electric field of , a negative direct current self-bias is superimposed and applied onto the surface to be formed. In order to prevent this direct current component from leaking to the outside, a capacitor is used to isolate the holder and the reaction vessel. Then, the first alternating voltage causes the plasma-activated gas to accelerate and collide onto the substrate by self-biasing, and the unnecessary charged-up charges on the substrate are removed by the second alternating voltage. In this way, even if the surface to be formed is an insulating organic material, a film can be formed on the surface in substantially the same manner as on a conductive surface.

One example of this thin film formation is ethylene (C2H4).

Hydrocarbon gases such as methane (CH4) and acetylene (CJz) or mixed gases of these and nitrogen fluoride or CzF
a.

CJs, CF4. By introducing a carbon fluoride gas such as carbon fluoride such as CHzh and decomposing it, a C-C bond similar to that of diamond having an SP3 orbital is created.
It has a specific resistance (specific resistance H
eV or more, preferably 1.5 to 5.5 eV, and a carbon film having properties similar to transparent diamond in the visible region, or carbon as the main component (the main subcomponents are hydrogen, fluorine, and nitrogen) A film was formed.

The translucent organic material used in the present invention has a specific resistance of 1×10×5
It is an insulating member with a resistance of Ωcm or more, and the materials used include polyester resin, alkyd resin, oil-free alkyd resin, unsaturated polyester resin, acrylic resin, and amine resin. In particular, for automobile lines, organic melting type organic materials such as acrylic lacquer, acrylic melamine, and block acrylic urethane were used.

When forming a film using the method of the present invention, a halogen element such as fluorine and nitrogen are mixed simultaneously with carbide gas during plasma CVD to create a film with a uniform concentration gradient in the thickness direction, and the main component is carbon. Multilayer composite membranes may be created with controlled presence or absence of coatings or additives.

The manufacturing method of the present invention will be described below according to the drawings.

"Example 1" FIG. 2 shows an outline of a plasma CVD apparatus for carrying out a method of forming a thin film on a substrate or member such as a front window of an automobile.

In the drawing, a reaction vessel (7) of the plasma CVD apparatus is separated from the outside by a gate valve (9). Gas type (30
), the carrier gas argon is added from (31), the reactive gas hydrocarbon gas such as methane or ethylene is added from (32), and the additive gas fluorocarbon (C
zF6. C: +Fs) from (33), oxygen which is the etching gas for the reaction vessel from (34), and valve (28).
), the nozzle (
25). When ethylene and carbon difluoride are introduced, the diamond-like carbon film (also referred to as DLC, which has a large number of sp' bonds to which hydrogen and fluorine are added, and the present invention includes DLC to which additives are added) It is possible to form a film whose main component is

In order to make a film with the same main component as this, C2F4. C:l
It may also be formed by introducing F8 from (32) and NH, from (33).

A first pair of electrodes having the same shape are provided above and below this reaction container (7) to form first and second electrodes (3-1).

(3-2) is made of aluminum metal mesh. The reactive gas is emitted downward from the nozzle (25). Further, a third electrode (13-
1), (13-2), ... (13-n) and other fourth
electrodes (13'-1), (13°-2)...
- (13'-n) (collectively referred to as the third and fourth electrodes) are arranged by sandwiching the base or members between each other. Substrate or member (1-), (1-2)
... (1-n) is an insulating material, but a second alternating voltage is applied thereto to make it substantially conductive in terms of alternating current, and a bias is applied. A plasma atmosphere or a positive sheath is created on the surface (1°) on which the organic substance is formed on the substrate or member (1), and a negative self-bias is applied. In order to actively generate this negative self-bias, the frequency of the second alternating voltage is set to 10Hz to 100Kllz, a low frequency such that ions spread between the third and fourth electrodes during a half cycle. And so. The substrate or member (1) has a surface (1') on which an organic substance is formed, and the reactive gas that has been turned into plasma by glow discharge due to the first high-frequency alternating voltage is uniformly dispersed in the reaction space (8), The plasma potential in the reaction space was made homogeneous.

Furthermore, in order to make the potential distribution in the plasma reaction space more equal, alternating voltages of two independent frequencies can be applied to the power supply system (40). The first alternating voltage is a high frequency of 1 to 100 MHz, for example 13.56 MtlzO, and the two power supplies (15-1) form a pair.

(15-2) That is, (15) leads to matching boxes (16-1) and (16-2) made of LCR circuits. The mutual phases in this matching box are adjusted by a phase adjuster (26), so that the signals can be supplied with a difference of 180 degrees or Oo from each other. It has a symmetrical or in-phase output, and the power supply (15-1), (15-2)
The respective negative ends (4-1) and (4-2) are connected to a pair of first and second electrodes (3-1) and (3-2), respectively. Also, each power supply (15-
1), (15-2) other end is grounded (5-1) (5-
2) It has been done. A second 10Hz to 100Ktlz, for example 50Hz alternating voltage is applied to the power supply (17), i.e. (17-1
), a pair of third electrodes (13-1) from (17-2)
), ... (13-n) and the fourth electrode (13"
-1)...(13'-n) and is applied. The pair of electrodes (13), (13')
The output is such that a self-bias is applied to the substrate or member (1) sandwiched between the pair of electrodes.

Plasma (8) is thus generated in the reaction space.

The exhaust system (25) exhausts unnecessary gas through a pressure regulating valve (21), a turbo molecular pump (22), and a rotary pump (23).

These reactive gases are present in the reaction space (60) at 0.001
~1.0 torr, for example, 0.05 torr.

In such a space, the frequency of 13.56 MHz is 0.
5~5KW (0.03~3W/cm2 per unit area)
For example, a first high frequency voltage of IKW (high energy of 0.6 W/cm" per unit area) is applied. Furthermore, by applying an alternating current bias with a second alternating voltage, a voltage of 200 to -600 V (for example, A negative self-bias voltage of 1 to -) is applied to the output, and a reactive gas accelerated by this negative self-bias voltage is sputtered onto a substrate or member to form a film, and a dense film is formed. We were able to.

The reactive gas was, for example, a mixed gas of ethylene and carbon fluoride. The ratio is CzFi/CzH4= 1/4~4/
1, typically 1/1. By varying this ratio, transmittance and specific resistance can be controlled. The temperature of the substrate or member (1) is typically maintained at room temperature, ˜150° C., without external heating. Thus, the resistivity on the surface to be formed is 1×106 to 5×10”Ωcm.
The film is also formed in close contact with the organic resin. A film containing carbon or carbon as a main component to which fluorine and hydrogen have been added and has an amorphous or crystalline structure that is transparent to visible light is 0.1 to 8 μm thick, for example, 0.5 μm (flat portion), 1 ~3 μm (convex portion) was generated. The film formation rate is 1
00-1000 people/min.

Thus, it is possible to form a coating mainly composed of carbon on the front windshield and other components, especially carbon containing 30 atomic % or less of hydrogen and 0.3 to 1° of χ fluorine mixed therein. was completed. 10 on organic matter
It was possible to provide a first carbon film made of only ethylene to a thickness of 0 to 2,000 people, and then form a multilayer film on top of which the main component was carbon to which fluorine and hydrogen were added.

"Example 2" This example is an example in which a film containing carbon as a main component was produced on the main part of a translucent organic material as shown in FIG. 1 using the apparatus used in Example 1.

In FIG. 1(A), the front window (1
) is shown. The cross section is shown in FIG. 1(B).

In FIGS. 1A and 1B, the translucent plastic (1) is lightweight and is made of, for example, acrylic resin. Substrate or member having the surface to be formed (
1) A wear-resistant protective film (45) containing carbon or carbon as a main component was provided thereon with a thickness of 0.1 to 8 μm.

In the present invention, in order to prevent the adhesion of dust due to the generation of static electricity, the coating mainly composed of carbon or fluorine-added carbon has a specific resistance of 1 x 106 to 5 x 10'2.
in the range of Ωcm, particularly preferably from 1×107 to lXl0”
The range was set to Ωcm.

FIG. 1(C) shows the window formed only on the surface. The vertical cross-sectional views of FIGS. 1(^) and (C) may be of a side window or a mirror surface. Figure 1 (D) is for a sphere, and (E) is for a cylinder. The present invention is excellent because these materials are subject to strong wind blowing in actual use, and mineral dust is likely to collide with them, resulting in devitrification and turbidity due to abrasion.

"Effects" The present invention is effective for both inorganic glass and organic translucent materials.In particular, the upper surface has a Vickers hardness of 600 to 3000 kg/cm with fluorine added for good drainage.
2, or a multilayer film of carbon (hydrogen is also added) having a Vickers hardness of 1,000 to 7,000 kg/cm 2 was coated in close contact with the organic material. As a result, it was possible to form a thick and wear-resistant film on convex portions that are exposed to the wind and rain and are exposed to dust.

Until now, the front windows of automobiles were extremely prone to becoming stiff on sunny days. However, according to the present invention, it has been possible to reduce the generation of static electricity caused by the collision of insulating dust on the surface and the accompanying dust adhesion.

As shown above, by controlling the optical energy hand of DLC, it is possible to block light in windows that are transparent and prevent dust from adhering, and it is also possible to use inorganic glass or organic materials that have heat resistance. The ability to adhere tightly to organic materials that are not present is effective because it realizes the possibility of making plastic windows, which until now could not be used at all due to their softness.

As is clear from the above description, the present invention is particularly effective for materials coated with organic resins or multilayer films thereof. The applications of this composite, as seen in many other examples, are enormous, especially since the carbon can be formed at low temperatures below 150°C, and therefore it is difficult to transform the organic matter of the underlying painted surface. The color tone remains the same, and its hardness and adhesion to substrates or members are extremely excellent.

[Brief explanation of the drawing]

FIG. 1 shows an example in which a carbon film or a protective film mainly composed of carbon is coated on a member such as a front window according to the present invention, and its essential parts. FIG. 2 shows an outline of a manufacturing apparatus for a plasma CVD apparatus according to the present invention.

Claims (1)

[Scope of Claims] 1. A light-transmitting member having insulating properties, the main component being a carbon film or carbon having a specific resistance of 1×10^6 to 5×10^1^2 Ωcm on the member surface. A member covered with a carbon film, characterized in that it is provided with a film that protects the carbon film. 2. In claim 1, the light-transmitting member comprises a front window, rear window, side mirror, or side window of an automobile, motorcycle, bicycle, ship, or aircraft that can be exposed to wind and rain. A member covered with a membrane. 3. A member covered with a carbon film according to claim 1, wherein the light-transmitting member is made of an organic material, and a light-transmitting carbon film is provided on the organic material. 4. A first pair of electrodes for generating high-frequency plasma is provided in a reaction container, an insulating member is provided in the reaction container, and the second electrode is placed with the member in between. having a pair of electrodes, applying an alternating current bias between the electrodes, introducing a carbonide gas into the atmosphere under reduced pressure, and applying a high frequency voltage to the first pair of electrodes; A method for producing a member covered with a carbon film, characterized in that carbon or a film containing carbon as a main component is formed on the member by turning the gas into plasma.