JPH06346246A - Production of formed body - Google Patents

Abstract

(57) [Abstract] [Purpose] A method for producing a molded product having good sharpness and excellent corrosion resistance by forming a diamond-like carbon film on a metal substrate and then fluorinating the surface of the carbon film. . [Structure] A diamond-like carbon film is formed on a surface of a metal substrate 7 by exciting a raw material gas containing carbon and hydrogen into contact with plasma to form a diamond-like carbon film, and then, the surface of the diamond-like carbon film contains fluorine. A fluorinated layer is formed by exciting the raw materials with plasma and bringing them into contact with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a molded article, and more particularly to a method for producing a molded article applicable to a kitchen knife having excellent sharpness, scratch resistance, rust resistance and the like. .

[0002]

Conventionally, carbon steel or stainless steel has been used for knives such as kitchen knives, scissors, knives, etc. However, knives made of carbon steel are prone to rust, and knives made of stainless steel are less likely to rust. However, there is a problem that the cutting edge is soft and the sharpness is deteriorated due to abrasion due to repeated use. Further, there is a problem that heavy metal ions adhere to plants and impair the taste of the stainless steel blade.

In order to solve such a problem, Japanese Patent Laid-Open No. 58-71095 discloses a blade made of ceramic. However, ceramic blades are
Since the toughness is inferior, the cutting edge is likely to spill out, and it takes time to polish the cutting edge.

In order to make up for such a drawback of the ceramic blade, Japanese Utility Model Publication No. 58-46566 proposes a blade metal base coated with a ceramic thin plate via an adhesive. However, in this method, since a thin ceramic plate has to be polished, the polishing process takes time, the cutting edge is easily damaged, and the ceramic thin plate is easily separated from the metal substrate.

In order to prevent the peeling of the ceramic layer, Japanese Patent Application Laid-Open No. 1-47849 discloses that T is formed on a metal substrate by a physical vapor deposition method such as ion plating or sputtering.
A method of coating a metal nitride or metal carbide ceramic film of iN, TiC, etc. to a thickness of 1 μm or more is disclosed. However, since this ceramic film is a crystalline film, there is a problem in corrosion resistance due to corrosion from grain boundaries.

In view of this, Japanese Utility Model Laid-Open No. 63-36466 proposes a blade in which a fluorine resin is applied on a ceramic coating to improve the corrosion resistance. There is a problem that the shape becomes thick and the shape changes, and the sharpness decreases.

Further, Japanese Patent Laid-Open No. 63-92345 discloses a medical cutting tool in which a diamond-like carbon film such as diamond or diamond-like carbon is coated on a substrate instead of a ceramic coating such as TiN or TiC. However, it is doubtful whether it can be used for cooking blades and the like which require lubricity and corrosion resistance more than medical blades.

Further, JP-A-2-250968 and JP-A-5-10426 disclose members coated with a hard carbon film containing fluorine by a chemical vapor phase method using plasma. It is doubtful whether or not it will be used for cooking knives.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks, and an object thereof is to form a diamond-like carbon film on a metal substrate and then fluorinate the surface of the carbon film. By doing so, it is to provide a method for producing a molded product having good sharpness and excellent corrosion resistance.

[0010]

In the present invention, first, a diamond-like carbon film is formed on a surface of a metal substrate by exciting a source gas containing carbon and hydrogen with plasma.

The diamond-like carbon film referred to in the present invention is
A crystalline diamond or amorphous diamond-like carbon having a C-Csp ³ bond state of 50% or more.

Examples of the source gas containing carbon and hydrogen include alkane gases such as methane, ethane, propane, butane, pentane and hexane; alkene gases such as ethylene, propylene, butene and pentene; pentadiene. , Alkadiene gases such as butadiene; Alkyne gases such as acetylene and methylacetylene; Aromatic hydrocarbon gases such as benzene, toluene, xylene, indene, naphthalene, phenanthrene; Cycloalkanes such as cyclopropane and cyclohexane Gases; cycloalkene-based gases such as cyclopentene and cyclohexene; alcohol-based gases such as methanol and ethanol; ketone-based gases such as acetone and methyl ethyl ketone; aldehyde-based gases such as methanal and ethanal Is mentioned. These gases may be used alone or in combination of two or more.

The raw material gas containing carbon and hydrogen is a mixture of the above-mentioned gases and hydrogen gas; carbon monoxide gas, carbon dioxide gas or the like composed of only carbon and oxygen, and the above-mentioned gases. Mixture; Mixture of carbon monoxide gas, carbon dioxide gas, etc., gas composed only of carbon and oxygen, and hydrogen gas; Carbon monoxide gas, carbon dioxide gas, etc., gas composed of only carbon and oxygen, oxygen gas, steam And the like.

Further, examples of the raw material gas containing carbon and hydrogen include a mixed gas of the above raw material gas and a rare gas. The rare gas is a gas composed of an element of Group 0 of the periodic table, and examples thereof include helium, argon, neon, and xenon. These may be used alone or in combination of two or more. Good.

When the above-mentioned rare gas is mixed, the electron density of plasma increases, so that the deposition rate of the diamond-like carbon thin film tends to increase.

The mixing amount of the rare gas in the above mixed gas is appropriately determined depending on the kind of the mixed gas, the film forming pressure, and the like. If the amount is too small or too small, the obtained thin film becomes graphite-like, and the diamond-like carbon thin film Since the film forming rate decreases, it is preferably 20 to 90 vol% in the mixed gas.

The amount of hydrogen gas mixed in the mixed gas is appropriately determined depending on the type of mixed gas used, film forming pressure, etc., and is not particularly limited.

As the carbon source, solids of carbon allotrope such as graphite and diamond can also be used, and they are used by being installed in hydrogen gas atmosphere plasma.

Means for exciting the source gas with plasma include, for example, a method of plasma decomposition by applying direct current; a method of plasma decomposition by application of high frequency; a method of plasma decomposition by microwave discharge; and electron cyclotron resonance. Plasma decomposition method; a method of thermally decomposing by heating with a hot filament, and the like. Among these, the method of decomposing plasma by electron cyclotron resonance is preferable because the film forming rate is high and the film forming temperature is low.

As a method for forming a diamond-like carbon film on a metal substrate, a physical vapor deposition method such as sputtering or ion plating method, a chemical vapor deposition method such as plasma CVD method, or the like is adopted. A plasma CVD method using a magnetic field microwave capable of controlling the temperature from room temperature is preferable.

The film thickness of the diamond-like carbon film is determined as necessary, but if it becomes thin, it may not be a continuous film, and it becomes difficult to form a film of high hardness. Adhesion is poor, so 0.05-5μ
m is preferable, and more preferably 0.1 to 1 μm.

In the present invention, the fluorinated layer is formed on the surface of the diamond-like carbon thin film formed on the metal substrate by exciting the raw material containing fluorine by plasma and bringing it into contact therewith.

As the raw material containing fluorine, carbon tetrafluoride, carbon hexafluoride, or other fluorocarbon gas, polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoroethylene (FEP) copolymer, etc. And solids such as fluorine-containing resins.

When a carbon fluoride gas is used as the above-mentioned fluorine-containing raw material, it may be used as a mixture with a rare gas such as argon or helium. 30 vo because it is graphitized and softened
It is preferably 1% or less.

The above-mentioned fluorine-containing raw material is excited by plasma, and hydrogen on the surface of the diamond-like carbon thin film is replaced with fluorine-containing excited species excited by plasma to form a fluorinated layer on the surface of the diamond-like carbon film. Form. The thickness of this fluorinated layer is preferably 200 Å or less in order to maintain high hardness. The portion to be fluorinated may be a part or the whole of the molded body, and is determined as necessary.

The surface of the diamond-like carbon film exhibits water repellency due to being fluorinated, but a contact angle to water is preferably 90 degrees or more in order to exhibit corrosion resistance.

Examples of the metal base material include carbon steel,
Stainless steel or the like is preferably used. The shape of the metal substrate is not particularly limited, and examples thereof include a plate shape, a linear shape, and a pipe shape.

As the metal base material used for the kitchen knife, for example, as shown in an enlarged view of the cross section of the cutting edge in FIG. 1, a carbon-containing material polished to have a cutting edge angle (θ) of 27 degrees is included. An example is carbon steel having an amount of 0.7% by weight and a quenching hardness of 58 ± 1 in Rockwell hardness (C scale).

When high adhesion is required for the metal base material, cleaning treatment such as washing for degreasing and dehydrating the surface of the base material, Ar (argon) or the like in a vacuum container used for film formation is performed. It is preferable to perform a known treatment such as plasma treatment with an inert gas.

<Method for forming diamond-like carbon film> The apparatus used in the present invention will be described below with reference to the drawings. FIG. 2 is a schematic cross-sectional view showing an example of an apparatus used in the method for producing a molded product of the present invention. In FIG. 2, 1
Is a vacuum container, and the vacuum container 1 is composed of a plasma generating chamber 2 and a film forming chamber 3. At the center of the side surface of the plasma generation chamber 2, a microwave oscillator 4 is connected to the plasma generation chamber 2 by a microwave introduction pipe 5, and a magnetic field is provided around the plasma generation chamber 2 and the microwave introduction pipe 5. The coil 6 is installed.

On the other hand, a holder 8 for holding the base material 7 is installed in the vacuum container such that the diamond-like carbon film forming surface of the metal base material 7 faces the microwave introducing tube 5. There is. Further, the holder 8 is connected to a DC bias power source 9 for applying a DC bias to the base material 7 by a conductive wire.

The holder 8 is connected to a cooling liquid circulator (not shown) for the case of forming a film at a low temperature of about 200 ° C. or less, and the cooling liquid 10 circulates inside the holder 8. is doing. A heating device 11 is provided for forming a film at a high temperature of about 200 ° C. or higher. In addition, the holder 8 has a thermocouple 12 for measuring the temperature of the back surface of the base material.
Is installed.

Two gas introduction pipes 13 and 14 for introducing a raw material gas are connected to the plasma generation chamber 2, and the gas introduction pipe 13 is provided at a position near the holder 8. The wall surface of the film forming chamber 3 is provided with an exhaust port 15 connected to an exhaust device (not shown) for adjusting the pressure inside the vacuum container 1.

The manufacturing method will be described below. First, the metal base 7 having a clean surface is placed in the vacuum container 1 by the holder 8, and then the vacuum container 1 is set to a high vacuum. The degree of vacuum at this time is preferably 10 ⁻⁴ Torr or less in order to eliminate the influence on the film formation due to the residual of other impurity gas.

The method of introducing the raw material gas is not particularly limited, and the raw material gas may be introduced all at once through the introduction pipes 13 or 14, or the component gases constituting the raw material gas may be introduced using the introduction pipes 13 and 14. You may introduce separately. However, when the latter introduction method is adopted, it is preferable to introduce the carbon-containing gas through the introduction pipe 13 near the metal base material 7.

Next, a magnetic field having a predetermined magnetic field strength is applied by the magnetic field coil 6, and a microwave of a predetermined frequency is generated by the microwave oscillator 4, and the vacuum container 1 is passed through the microwave introduction tube 5 and the quartz window 16 through the quartz window 16. Introduce microwave.

As a result, the raw material gas introduced into the vacuum vessel 1 is excited into a plasma state, and the carbon-containing active species come into contact with the metal base material 7, whereby a diamond-like carbon film is formed on the base material 7. It is formed.

Although the predetermined magnetic field strength and frequency are not particularly limited, it is preferable that the predetermined magnetic field strength and frequency are values satisfying the conditions required for electron cyclotron resonance. This condition means that the cyclotron frequency of an electron in a constant magnetic field and the microwave frequency match, and for example, when the microwave frequency is 2.45 GHz, the magnetic field strength is 87.
It is 5 gauss. At this time, it is preferable to apply a DC bias to the metal substrate 7 in order to form a uniform thin film,
The DC bias value is preferably −300 to 300 V, and −10 to 1 in the case of a crystalline diamond-like carbon film.
00V is preferable, and in the case of a non-quality diamond-like carbon film, -150 to 10V is preferable.

The metal base material 7 during film formation is held by a holder 8 equipped with a cooling device, and the temperature thereof is from room temperature to 1000.
It is preferably maintained in the range of ° C. When the film is formed at a low temperature that has a small thermal effect on the base material, the temperature of the metal base material 7 can be set by controlling the temperature of the holder 8 in contact therewith. Further, the base material 7 is set to a temperature of plasma or lower via the holder 8.

The temperature of the base material 7 is controlled by a liquid or gas circulation method, a heating wire, an electric heating method or the like. However, since the plasma during film formation has a temperature of 200 ° C. or higher, the film formation temperature can be controlled. In order to maintain the temperature at 200 ° C. or lower, a liquid circulation system having a large heat capacity is preferable. At this time, examples of the liquid to be circulated include liquids that have been heated or cooled to a predetermined temperature, such as water, ethylene glycol (antifreeze liquid), alcohols, and liquid nitrogen, liquid helium, etc. when the temperature is further lowered. It is preferably used.

When the film is formed at a high temperature, the metal substrate 7
Examples of the method include a method in which the temperature of the holder 8 in contact with the substrate is controlled by energization and heating, and a method in which the substrate 7 is irradiated with heat rays.

<Formation of Fluorinated Layer> Next, a method of forming a fluorinated layer on the diamond-like carbon film formed above will be described. The method for forming the fluorinated layer is preferably the same as the method used for forming the diamond-like carbon thin film in order to improve productivity and adhesion, and it is preferable to use plasma utilizing an electron cyclotron resonance method. .

After forming the diamond-like carbon film on the metal base material 7, the inside of the vacuum container 1 is set to a high vacuum again. At this time, the degree of vacuum is preferably 10 ⁻⁴ Torr or less in order to eliminate the influence of the residual of other impurity gas.

The method for introducing the fluorine-containing raw material is not particularly limited. For example, when a fluorocarbon gas is used, it may be introduced all at once through the introduction pipes 13 or 14. The component gases forming the raw material gas may be separately introduced using the tubes 13 and 14. However, when the latter introduction method is adopted, it is preferable to introduce the carbon-containing gas through the introduction pipe 13 near the metal base material 7.

Then, a magnetic field having a predetermined magnetic field strength is applied by the magnetic field coil 6, and a microwave having a predetermined frequency is generated by the microwave oscillator 4, and the vacuum container 1 is passed through the microwave introduction tube 5 and the quartz window 16 through the quartz window 16. Introduce microwave.

As a result, the fluorine-containing raw material gas introduced into the vacuum chamber 1 is excited into a plasma state, and the fluorine-containing active species come into contact with the diamond-like carbon film, so that the carbon film is fluorinated. A layer is formed.

The above-mentioned predetermined magnetic field strength and frequency are not particularly limited, but it is preferable that the predetermined magnetic field strength and frequency satisfy the conditions required for electron cyclotron resonance. This condition means that the cyclotron frequency of an electron in a constant magnetic field and the microwave frequency match, and for example, when the microwave frequency is 2.45 GHz, the magnetic field strength is 87.
It is 5 gauss. At this time, in order to form a uniform fluorinated layer, it is preferable to apply a DC bias to the metal substrate 7, and the DC bias value is preferably -200 to 200V, more preferably -100 to 0V.

The temperature for forming the fluorinated layer is from room temperature to 1
The temperature is preferably maintained at 000 ° C, and more preferably from room temperature to 500 ° C in order to control the alteration of the diamond-like carbon thin film and the metal substrate 7. When the film is formed at a temperature that has a small thermal effect on the metal base material 7, the temperature of the base material 7 is set by controlling the temperature of the holder 8 that contacts the base material 7.

[0049]

EXAMPLES Examples of the present invention will be described below.

(Example 1) In the apparatus shown in FIG.
The stainless steel holder 8 in the vacuum container 1 is degreased and washed, and the stainless steel (SUS440C) metal base material (cooking knife) 7 shown in FIG. 1 is installed, and the inside of the vacuum container 1 is 1 × 10 ^−5.
After reducing the pressure to Torr, it was heated to 500 ° C. by the heating device 11.

Then, a mixed gas of methanol gas having a gas flow rate of 60 sccm and argon gas having a gas flow rate of 140 sccm was introduced into the vacuum vessel 1 as a mixed gas through the gas introduction pipe 14 to a pressure of 0.1 Torr, Frequency 2.45 GHz, 1.2 kW microwave and 2.2
A magnetic field of k gauss was applied and a direct current bias current of 30 V was applied to form a film for 4 hours.

The magnetic field strength near the surface of the metal substrate 7 during film formation was 875 Gauss, and a film having a thickness of 1.0 μm was obtained. The obtained film was evaluated by an electron microscope and Raman spectroscopy,
It was confirmed that it was composed of diamond polycrystals of fine crystals (crystal diameter 500Å).

Further, the inside of the vacuum chamber 1 is again set at 1 × 10 ^-5 T
After reducing the pressure to orr, a carbon tetrafluoride gas was introduced from the gas introduction pipe 14 at a gas flow rate of 200 sccm to obtain 0.1 Torr.
After the pressure was set to r, a microwave of 1.2 kW was applied and a -30 V bias was applied to the metal substrate 7 to perform fluorination treatment for 5 minutes to obtain a molded body.

Regarding the film obtained by the fluorination treatment, X
As a result of measuring the presence or absence of the fluorinated layer and the thickness thereof by a line electron spectroscopy method, it was confirmed that 72 atomic% of fluorine was present and a fluorinated layer having a thickness of about 70Å was formed.

[Evaluation of Performance of Molded Article] The following evaluation was performed on the obtained molded article (cooking knife). (1) Sharpness test Fix the knife edge of the kitchen knife for cooking up and press the newspaper 8 m.
After being piled up in a thickness of m, it was placed on the cutting edge and reciprocally moved along the cutting edge in the horizontal direction for a distance of 28 mm while applying a load of 1 kg. One reciprocation is defined as one cut, and after measuring the number of sheets cut at a fixed number of cuts, the number of cuts (horizontal axis) and the number of cut sheets for each number of cuts (vertical axis) are measured. A graph (shown in FIG. 3) representing the relationship was created and the sharpness was evaluated. (2) Corrosion resistance test The number of days until rust was generated was observed by leaving it in a thermo-hygrostat set at a temperature of 60 ° C and a humidity of 96% for a certain period of time, and shown in Table 1. (3) Contact angle measurement A drop of water was dropped on the obtained fluorinated layer and the contact angle was measured.
It was shown to.

(Embodiment 2) In the apparatus shown in FIG.
The stainless steel holder 8 in the vacuum container 1 was provided with the same metal substrate 7 as in Example 1, which had been degreased and washed, and the vacuum container 1 was depressurized to 1 × 10 ⁻⁵ Torr, and then the heating device 11 was turned on. Two
Heated to 50 ° C. Then, ethylene gas having a gas flow rate of 50 sccm was introduced into the vacuum container 1 through the gas introduction pipe 14 to a pressure of 1 × 10 ⁻³ Torr, and then the frequency was changed to 2.4.
A film was formed for 2 hours by applying a microwave of 5 GHz, 1.2 kW and a magnetic field of 2.2 kGauss, and by applying a DC bias current of -100V. Metal base material 7 during film formation
The magnetic field strength near the surface is 875 Gauss and the film thickness is 0.5.
A μm film was obtained. As a result of evaluating the obtained film by an electron microscope and Raman spectroscopy, it was confirmed that the film was an amorphous diamond-like carbon film.

Further, the same fluorination treatment as in Example 1 was performed to obtain a molded body. The presence or absence of the fluorinated layer and the thickness of the film obtained by the fluorination treatment were measured by X-ray electron spectroscopy. As a result, it was confirmed that 75 atomic% of fluorine was present and the fluorinated layer was 130 Å. It was

The above-mentioned molded products were evaluated in the same manners as in Example 1 (1) to (3), and the results are shown in Table 1 and FIG.
It was shown to.

Example 3 After forming an amorphous diamond-like carbon film on a metal substrate in the same manner as in Example 2, the inside of the vacuum chamber 1 was depressurized to 1 × 10 ⁻⁵ Torr. Then, a carbon tetrafluoride gas having a gas flow rate of 170 sccm and a helium gas having a gas flow rate of 30 sccm were introduced into the vacuum vessel 1 through the introduction pipe 14 to a pressure of 0.1 Torr, and then a microwave of 1.2 kW was introduced. A DC bias current of -30 V was applied to the base material to form a film for 5 hours to obtain a molded body. The presence or absence of the fluorinated layer and the thickness of the film obtained by the fluorination treatment were measured by X-ray electron spectroscopy, and as a result, it was confirmed that 65 atomic% of fluorine was present and that the fluorinated layer was 70Å. It was The same evaluations (1) to (3) as in Example 1 were performed on the above-mentioned molded body, and the results are shown in FIG. 1 and Table 1.

Comparative Example 1 A nitrogen atmosphere pressure of 7 × 10 ⁻⁴ T was obtained by a known arc discharge type ion plating method.
Orr, ionization voltage 40V, substrate voltage −500V, temperature 500 ° C., thickness 1.
A compact having a TiN layer of 0 μm was obtained. The obtained molded product was evaluated in the same manners (1) and (2) as in Example 1, and the results are shown in FIG. 1 and Table 1.

(Comparative Example 2) On the metal substrate on which the TiN layer obtained in Comparative Example 1 was formed, the fluororesin (main agent) diluted with xylene and the isocyanate (curing agent) were mixed at 5: 1 (weight ratio). The coating composition (“Lumiflon LF200C” manufactured by Asahi Glass Co., Ltd.) mixed with was applied with a brush to a thickness of 1.0 μm, and dried at 150 ° C. to form a coating film to obtain a molded body. For the obtained molded body, the same (1) as in Example 1 was used.
And (2) were evaluated, and the results are shown in FIG. 1 and Table 1.

[0062]

[Table 1]

[0063]

Industrial Applicability The method for producing a molded article of the present invention is as described above, and after the diamond-like carbon thin film is formed on the metal substrate, the surface of the thin film is fluorinated to obtain good sharpness. Provide a molded body having excellent corrosion resistance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of a molded body (cooking knife) obtained according to the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of an apparatus used in the present invention.

FIG. 3 is a graph showing the results of the sharpness test of the molded body (cooking knife) obtained in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Plasma generation chamber 3 Film-forming chamber 4 Microwave oscillator 5 Microwave introduction pipe 6 Magnetic field coil 7 Metal base material 8 Holding device 9 DC bias power supply 10 Circulating liquid 11 Heating device 12 Thermocouple 13, 14 Gas introduction pipe 15 Exhaust port 16 Quartz window 17 Cutting edge 18 Fluorinated diamond-like carbon film

Claims (1)

[Claims] 1. A diamond-like carbon film is formed on a surface of a metal substrate by exciting a raw material gas containing carbon and hydrogen into contact with plasma to form a diamond-like carbon film. Then, the surface of the diamond-like carbon film contains fluorine. A method for producing a molded article, comprising forming a fluorinated layer by exciting a raw material with plasma and bringing it into contact with each other.