JPH062945B2 - Substrate surface modification method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a substrate surface formed by forming a compound thin film containing a fluorine-carbon bond on a substrate composed of a metal, a metal oxide, ceramics, a plastics and the like. The present invention relates to a reforming method of.

Conventional technology and its problems Chemical resistance, hydrophobicity, abrasion resistance, lubricity, etc. are formed by forming a thin film of fluorine-containing compound on the surface of a substrate made of metal, metal oxide, ceramics, plastics, etc. The method of giving is known. As a method of this kind, in general,
A method of wet-coating tetrafluoroethylene is widely used, but tetrafluoroethylene is expensive,
Further, on substances such as metals and ceramics, it is difficult to form a film having excellent adhesiveness because tetrafluoroethylene itself has a low surface energy, and it peels off during use and its function deteriorates. There is a problem.

Also, a method of forming carbon fluoride on the metal surface by a chemical treatment method in fluorine gas has been studied,
In addition to the danger that fluorine gas is dangerous, the processing conditions are complicated and not suitable for practical use.

Further, when the metal, ceramics, etc. are directly treated with the fluorine-containing plasma gas, the metal, the ceramics,
Since it contains only a trace amount of carbon, it is not possible to form a fluorinated carbon compound, and sometimes when the metal is directly treated with a fluorine-containing plasma gas, the surface of the metal is hydrophilic as it is. It becomes brittle and cannot serve the role of protecting metals.

Means for Solving the Problems The present inventors formed a strong thin film of a compound having a fluorine-carbon bond on the surface of a metal, ceramics, plastics, etc., to provide hydrophobicity, lubricity, and wear resistance. As a result of extensive research aimed at imparting chemical resistance and the like, plasma gas generated by discharging a mixed gas containing a hydrocarbon compound and a sulfur fluoride compound is used as a base for metals, ceramics, plastics and the like. It has been found that a thin film of a compound having a fluorine-carbon bond can be uniformly and firmly formed on a substrate by bringing it into contact with a material. The present invention is based on such knowledge.

That is, in the present invention, in the presence of a mixed gas containing a hydrocarbon compound and a sulfur fluoride compound, a plasma gas generated by discharge is brought into contact with a base material to thereby obtain a compound having a fluorine-carbon bond on the base material surface. The present invention relates to a method for modifying a surface of a base material, which comprises forming a thin film.

In the present invention, in the presence of a mixed gas containing a hydrocarbon compound and a sulfur fluoride compound, a plasma gas generated by discharge is brought into contact with a base material to form a fluorine-containing compound on the substrate. A thin film can be formed. Examples of the hydrocarbon compound that can be used in the method of the present invention include CH ₄ , C ₂ H ₄ , C ₂ H ₆ , and C ₃ H.
₈ , C ₄ H _{10 and the} like can be exemplified, and as the sulfur fluoride compound,
Examples include SF _{6 and the} like. The mixing ratio may be appropriately determined according to the required properties of the thin film.

If necessary, a gas such as N ₂ or He can be added to this mixed gas to adjust the discharge voltage or the like.
Further, hydrogen, oxygen or the like may be mixed in order to improve the performance of the formed film and the performance of bonding with the base material. The method of the present invention is advantageous in terms of safety, since fluorine molecule gas, which is used as a fluorine raw material and is dangerous in handling, is not used in the conventional production of fluorinated graphite by the discharge plasma method.

Examples of the plasma generation method used in the present invention include direct current glow discharge or low frequency discharge by an internal electrode method, high frequency discharge by an internal electrode method, external electrode method or coil type method, microwave discharge by a waveguide type method, electron cyclotron. An induction coil type high-frequency discharge that does not use a resonance discharge (ECR discharge) electrode and the like can be cited, and the method is not limited to these, and any method can be used as long as it is a method of generating plasma by the discharge and causing a reaction with the carbon-containing film. Either method may be used.

The discharge treatment method may be a conventional method, and appropriate discharge conditions may be determined according to the properties required for the surface of the base material under the condition that the fluorine-containing plasma is generated.

In the present invention, the base material is not particularly limited, but for example, metal, metal oxide, ceramics, plastics and the like can be used. The type of these base materials is not particularly limited, but as the metal, for example, copper, iron,
Nickel, aluminum, chrome, tungsten, tin,
Examples include simple metals including zinc, silicon, manganese, titanium, indium, etc., and alloys thereof.
Examples of the metal oxide include oxides of the above metals.
Further, as the ceramics, glasses such as silicate glass, quartz glass, borate glass, and phosphate glass,
Examples include cements such as alumina cement, Portland cement, and magnesia cement, magnesia, zircon, alumina, titanium oxide, silicon carbide, silicon nitride, and the like. There is no particular restriction on plastics,
A wide variety of materials can be used, such as polyethylene resin, polypropylene resin, polyacetal resin, acrylic resin, nylon resin, cellulose resin, polycarbonate resin, phenoxy resin, polyester resin, polyurethane resin, diallyl phthalate resin, phenol formaldehyde resin, urea resin. , Melamine / aldehyde resin, epoxy resin, furan resin, xylene resin, silicone resin, polystyrene resin, vinyl resin, alkyd resin, chlorinated polyether resin and the like.

The shape of the base material is not particularly limited, and may be any shape such as a round bar shape, a prismatic shape, and a plate shape.

The processing conditions may be appropriately determined according to the required properties of the thin film.

The position of the base material placed in the discharge device in the present invention may be within the electric field for generating plasma, or outside the electric field as long as the gas passing through the plasma of the fluorine-containing compound reaches in an active state. May be In particular, when plastics is used as the base material, for example, when the base material is subjected to microwave discharge in an electric field, the plastics may be melted. Instead, it is necessary to place the substrate outside the electric field and within the range where the active gas passing through the plasma reaches.

Further, when the substrate is discharged in an electric field and discharged, a thin film of a compound having a fluorine-carbon bond may be formed while etching the substrate surface. It is necessary to determine the processing conditions accordingly.

According to the method of the present invention, the type of sample gas, the mixing ratio, the pressure,
The degree of fluorination of the carbon-containing film can be determined by adjusting the discharge method, for example, alternating current, direct current, high frequency method, discharge time, electrode distance, substrate temperature, and repeated ON / OFF of discharge. Can be controlled, and it is possible to adjust the hydrophobic performance of the surface of the base material. The degree of fluorination can be quantitatively measured by the F / C ratio calculated by X-ray photoelectron spectrum (ESCA spectrum) analysis.

EFFECTS OF THE INVENTION According to the method of the present invention, it is possible to form a thin film of a compound having a fluorine-carbon bond, which is uniform and strong and has excellent adhesiveness, on the surface of a base material regardless of the type of the base material. In addition, the method of the present invention does not use a fluorine molecular gas as a fluorine raw material, and thus is a method having excellent safety. Further, according to the method of the present invention, there is a great advantage that the target substance can be obtained in an extremely short time, as compared with a chemical treatment method and the like.

Furthermore, according to the method of the present invention, it is possible to form a thin film of a compound having a fluorine-carbon bond which is more hydrophobic than polytetrafluoroethylene, and the substrate treated by the method of the present invention is It has excellent chemical resistance, hydrophobicity, abrasion resistance, lubricity, etc.

The substrate treated by the method of the present invention is useful, for example, in the case of plastics, magnetic tape, moisture-proof film for precision machinery, artificial blood vessel, blood back, etc., and in the case of ceramics, artificial bone, Can be effectively used as roof tiles,
In the case of metal, it has a wide range of uses, such as being able to be used as a material for machines used in liquids, as a sliding material, and the like.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples. The gas flow rate in the examples is a value measured under atmospheric pressure.

Example 1 As the plasma discharge device, the plasma discharge device by high frequency discharge shown in FIG. 1 was used. The plasma discharge device shown in FIG. 1 basically comprises a raw material, a carrier gas supply path 1, a high frequency power supply 2, a plasma reaction system 3, a discharge electrode 4 and an exhaust path 5.

A SUS304 thin plate pretreated by a sputtering method for 5 minutes in Ar gas of 0.5 torr was used as a sample, and the sample was placed on the discharge electrode of the above plasma discharge device, and SF ₆ -CH _{4 with a} prepressure of 0.2 torr. A mixed gas (SF ₆ 0.134 torr, CH ₄ 0.066 torr) was added to 15 cm ³ (NT.
P. ) / Min while flowing at 50W, 13.5M
A high frequency power (radio wave) of Hz was applied to the electrodes to generate plasma, which was then processed for 3 minutes. As a result, a film having a thickness of about 1.0 μm was formed on the surface of the sample, and the contact angle of water droplets was 99 to 101 degrees, and the average was about 100 degrees.

[Brief description of drawings]

FIG. 1 is a schematic view of the plasma discharge device used in Example 1. In the figure, (1) is a raw material, a carrier gas supply passage,
(2) is a high frequency power supply, (3) is a plasma reaction system, (4)
Is a discharge electrode, and (5) is an exhaust path.

Claims (1)

[Claims] 1. A thin film of a compound having a fluorine-carbon bond on the surface of a base material by bringing a plasma gas generated by discharge into contact with the base material in the presence of a mixed gas containing a hydrocarbon compound and a sulfur fluoride compound. A method for modifying a surface of a base material, comprising: