JP2009137077A - Polycarbonate laminate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laminate of a carbon film and polycarbonate resin to which higher characteristics are imparted as to chemical resistance of a polycarbonate resin material while maintaining high transparency of the polycarbonate resin material. <P>SOLUTION: This polycarbonate laminate comprises the polycarbonate resin material and the carbon film deposited on the surface of the polycarbonate resin material and having a film thickness of 50 nm to 10 μm and a surface roughness Ra of 20 nm or less, wherein the carbon film has a spectrum peak at 41-42° of a Bragg angle (2θ±0.3°) in an X-ray diffraction spectrum with CuK<SB>α1</SB>rays. The laminate has high light transmittance of 55% or more in light transmittance in wavelength 400-800 nm and 80% or more in light transmittance in wavelength 500-800 nm. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a laminate of a carbon film and a polycarbonate material having new physical properties.

  In recent years, resin materials are used everywhere in life. For example, the polycarbonate (hereinafter referred to as PC) resin described below is one of them.

  PC resin is a kind of thermoplastic resin and is an engineering plastic used for industrial products such as electric products and automobiles, and has excellent characteristics such as high heat resistance, impact resistance, flame retardancy, and visible light transmittance. Due to such characteristics, PCs are used in various fields such as electronic devices, automobiles, architecture, and medical instruments.

  As described above, the PC resin product is a resin that is expected to greatly expand its application and that enables metal replacement. On the other hand, PC has low chemical resistance and is dissolved or decomposed in alcohol, acid, alkali, aromatic hydrocarbon, and chlorinated aliphatic hydrocarbon. Also, even if it is stable under static conditions such as room temperature and no load, there are many chemicals and substances that are affected under high temperature and forced bending stress. Therefore, in order to use PC resin products more widely, it is necessary to further improve the chemical resistance of PC resin products.

  On the other hand, diamond having high chemical resistance is already known (Patent Document 1, etc.) and has been desired as a laminated material for improving the characteristics of the PC resin material as described above. For example, if it is possible to laminate a diamond film on a PC resin material, the chemical resistance of the PC resin product will be further enhanced. However, in the diamond film laminating process, it is necessary to keep the temperature of the base material to be laminated at a high temperature of 800 ° C. or higher. Conventionally, there has been a problem that it is impossible to improve the characteristics by laminating a diamond film on a resin material that cannot withstand such high temperatures. Accordingly, it has been desired to develop a laminate material and a technique that can improve the chemical resistance of a PC resin material and can be laminated at a low temperature instead of the diamond film lamination.

  A major feature of PC resin is its high optical transparency. Therefore, it is desired to maintain the high transparency when improving the chemical resistance of the PC resin material.

In addition, plasma vapor chemical vapor deposition (CVD) is generally used for the lamination of diamond films and the deposition of carbon films having excellent characteristics as described in Patent Document 1. In this case, the source gas is usually a mixed gas of hydrogen and methane, and the mixing ratio of hydrogen gas is generally 90% or more. Therefore, in the lamination process, the resin material is exposed to a large amount of hydrogen plasma. However, since the reactivity of hydrogen plasma is very high, there is a big problem that the resin material is damaged by the reaction with hydrogen plasma.
Furthermore, there is a problem that the resin material of the substrate is melted due to heating from plasma during plasma processing, and if the processing temperature is lowered to avoid this, it is difficult to deposit a diamond film or a carbon film. was there.
Further, even if a conventional diamond film can be laminated on a polycarbonate substrate, the transmittance is extremely lowered and the characteristics of the polycarbonate are lost.
International Publication No. 2005/103326 Pamphlet

  The present invention has been made in view of the circumstances as described above, and the object thereof is to impart higher characteristics with respect to chemical resistance of the PC resin material while maintaining high transparency of the PC resin material. Another object of the present invention is to provide a laminate of a carbon film and a PC resin, and a carbon film deposition method on a substrate made of a PC resin material.

  As a result of intensive studies in order to achieve the above object, the present inventors have deposited a carbon film having high optical transparency and chemical resistance on the PC resin material. It has been found that a laminate of a carbon film and a PC resin can be formed, which has higher properties regarding chemical resistance while maintaining optical transparency.

The present invention has been completed based on these findings, and is as follows.
(1) A polycarbonate resin material and a carbon film having a film thickness of 50 nm to 10 μm and a surface roughness Ra of 20 nm or less deposited on the surface of the polycarbonate resin material, the carbon film being formed of CuK _α1 wire A polycarbonate laminate comprising a spectrum peak at 41 to 42 ° of a Bragg angle (2θ ± 0.3 °) in an X-ray diffraction spectrum.
(2) The polycarbonate laminate according to (1), wherein the light transmittance at a wavelength of 400 to 800 nm is 55% or more.
(3) The polycarbonate laminate according to (1), wherein the light transmittance at a wavelength of 500 to 800 nm is 80% or more.
(4) The polycarbonate laminate according to any one of (1) to (3), having a thermal conductivity of 30 W / mK or more and a resistance value of 1 × 10 ⁷ Ωcm or more (100 ° C.).

  The laminate of the carbon film and PC resin of the present invention can further increase chemical resistance while maintaining the optical transparency of the conventional PC resin material. Furthermore, according to the carbon film deposition method of the present invention, not only can the PC resin material used as the base material be prevented from being damaged by plasma, but also the PC resin material can be prevented from melting or thermally deforming.

FIG. 1 is a sectional view showing an outline of a laminate of a carbon film and a resin (PC material) according to the present invention.
Laminate of the carbon film and the PC resin of the present invention, by laminating a carbon film of PC resin and the film thickness 50Nm～10myuemu, and the carbon film, the X-ray diffraction spectrum by Cu K _{[alpha] 1} ray at Bragg angles ( 2θ ± 0.3 °) is a laminate having a spectrum peak at 41 to 42 °.

In the present invention, as pretreatment of the plasma CVD treatment, nanocrystal diamond particles, cluster diamond particles or graphite cluster diamond particles are attached to a PC resin material, or adamantane (C ₁₀ H ₁₆ ) or a derivative thereof. Or it is preferable to attach the multimer.

  Nanocrystalline diamond particles are usually diamond produced by explosive synthesis or by grinding diamond synthesized at high temperature and pressure. Cluster diamond particles are aggregates of nanocrystal diamond particles, and graphite cluster diamond particles are cluster diamond particles containing a large amount of graphite and amorphous carbon components.

  Nanocrystal diamond is a colloidal solution in which nanocrystal diamond by explosive synthesis is dispersed in a solvent from NanoCarbon Research Laboratories, etc., and nanocrystal diamond powder produced by grinding, or in which it is dispersed in a solvent. Already sold by Tomei Diamond Co., Ltd. The nanocrystal diamond particles used in the present invention have an average particle size of 4 to 100 nm, preferably 4 to 10 nm. The nanocrystal diamond particles are described in detail in the literature, for example, in “Hiraki Makita, New Diamond Vol.12 No. 3, pp. 8-13 (1996)”.

In the pretreatment for depositing nanocrystal diamond particles on a PC resin material, the particles are first dispersed in water or ethanol. At this time, in order to improve the dispersibility, a surfactant (for example, sodium lauryl sulfate ester, sodium oleate, etc.) is added, the substrate is immersed in this dispersion and subjected to an ultrasonic cleaner, and then the substrate is immersed in ethanol. After performing ultrasonic cleaning by immersion in the substrate, the substrate is taken out and dried.
In this way, it is possible to obtain a PC resin material that has been subjected to a pretreatment for attaching nanocrystal diamond particles to the surface. The adhesion of the nanocrystal diamond particles to the PC resin material is due to a part of the particles being embedded in the substrate surface by a physical force in the ultrasonic cleaning process.
The adhesion ratio of the nanocrystal diamond particles to the substrate surface is preferably 10 ⁹ to 10 ¹² , more preferably 10 ¹⁰ to 10 ¹¹ per 1 cm ² . Diamond particles adhering to the resin material act as seed crystals for carbon film growth in the plasma CVD process.

  At this time, by diluting the concentration of the nanocrystal diamond particles dispersed in the dispersion medium (water, ethanol, etc.), the adhesion ratio of the nanocrystal diamond particles adhering to the substrate surface can be reduced. Thereby, the nucleation density of carbon particles can be lowered in the plasma CVD process, and a discontinuous film made of an aggregate of carbon particles can be obtained instead of a continuous film. The surface density of the carbon particles in this aggregate can be controlled by the concentration of the nanocrystal diamond particles in the dispersion solution. Furthermore, the particle size of the carbon particles can be controlled by the time for performing the plasma CVD process. In addition, by making the concentration very thin, an integrated body made of isolated carbon particles on the substrate can be produced. Furthermore, only the carbon particles can be obtained by removing the substrate from the aggregate by treating the aggregate with an organic solvent or the like.

  Further, as another pretreatment method for attaching nanocrystal diamond particles on the substrate, a method of spin-coating the nanocrystal diamond dispersion on the substrate and then drying it is also effective. This pre-treatment method using spin coating can provide the same adhesion effect as the above ultrasonic cleaning method.

  Cluster diamond particles are agglomerates of nanocrystal diamond produced by an explosive synthesis method and are excellent in transparency, and are already sold by Tokyo Diamond Tool Mfg. Co., Ltd. In the cluster diamond particles used in the present invention, the particle size distribution is preferably 4 to 100 nm, more preferably 4 to 10 nm. The cluster diamond particles are described in detail in the document “Hiroshi Makita, New Diamond, Vol.12 No. 3, p.8-13 (1996)”.

In the pretreatment for attaching the cluster diamond particles on the PC resin material, the particles are first dispersed in water or ethanol. At this time, in order to improve the dispersibility, a surfactant (for example, sodium lauryl sulfate ester, sodium oleate, etc.) is added, the substrate is immersed in this dispersion and subjected to an ultrasonic cleaner, and then the substrate is immersed in ethanol. After performing ultrasonic cleaning by immersion in the substrate, the substrate is taken out and dried.
In this manner, a resin material having cluster diamond particles attached to the surface can be obtained. The adhesion of the cluster diamond particles to the PC resin material is due to a part of the particles being embedded in the substrate surface by a physical force in the ultrasonic cleaning process.
The adhesion ratio of cluster diamond particles to the substrate surface is preferably 10 ⁹ to 10 ¹² , more preferably 10 ¹⁰ to 10 ¹¹ per 1 cm ² . Diamond particles adhering to the PC resin material act as seed crystals for carbon film growth in the plasma CVD process.

  At this time, by reducing the concentration of cluster diamond particles dispersed in a dispersion medium (water, ethanol, etc.), the adhesion ratio of cluster diamond particles adhering to the substrate surface can be reduced. Thereby, the nucleation density of carbon particles can be lowered in the plasma CVD process, and a discontinuous film made of an aggregate of carbon particles can be obtained instead of a continuous film. The surface density of the carbon particles in this aggregate can be controlled by the concentration of cluster diamond particles in the dispersion solution. Furthermore, the particle size of the carbon particles can be controlled by the time for performing the plasma CVD process. In addition, by making the concentration very thin, an integrated body made of isolated carbon particles on the substrate can be produced. Furthermore, only the carbon particles can be obtained by removing the substrate from the aggregate by treating the aggregate with an organic solvent or the like.

  Further, as another pretreatment method for attaching cluster diamond particles on the substrate, a method of spin-coating the cluster diamond dispersion on the substrate and then drying it is also effective. This pre-treatment method using spin coating can provide the same adhesion effect as the above ultrasonic cleaning method.

In the pretreatment for attaching graphite cluster diamond particles on a PC resin material, the particles are first dispersed in water or ethanol. At this time, in order to improve the dispersibility, a surfactant (for example, sodium lauryl sulfate ester, sodium oleate, etc.) is added, the substrate is immersed in this dispersion and subjected to an ultrasonic cleaner, and then the substrate is immersed in ethanol. After performing ultrasonic cleaning by immersion in the substrate, the substrate is taken out and dried.
In this way, a PC resin material having graphite cluster diamond particles attached to the surface can be obtained. The adhesion of the graphite cluster diamond particles to the PC resin material is due to a part of the particles being embedded in the substrate surface by a physical force in the ultrasonic cleaning process.
The adhesion ratio of diamond particles to the substrate surface is preferably 10 ⁹ to 10 ¹² , more preferably 10 ¹⁰ to 10 ¹¹ per 1 cm ² . Diamond particles adhering to the PC resin material act as seed crystals for carbon film growth in the plasma CVD process.

  At this time, by reducing the concentration of the graphite cluster diamond particles dispersed in the dispersion medium (water, ethanol, etc.), the adhesion ratio of the graphite cluster diamond particles adhering to the substrate surface can be reduced. Thereby, the nucleation density of carbon particles can be lowered in the plasma CVD process, and a discontinuous film made of an aggregate of carbon particles can be obtained instead of a continuous film. The surface density of the carbon particles in this aggregate can be controlled by the concentration of the graphite cluster diamond particles in the dispersion solution. Furthermore, the particle size of the carbon particles can be controlled by the time for performing the plasma CVD process. In addition, by making the concentration very thin, an integrated body made of isolated carbon particles on the substrate can be produced. Furthermore, only the carbon particles can be obtained by removing the substrate from the aggregate by treating the aggregate with an organic solvent or the like. Furthermore, when a continuous film is formed on a substrate, a free-standing film can be formed by removing the substrate.

  Further, as another method of pretreatment for attaching the graphite cluster diamond particles on the substrate, a method of spin-coating the graphite cluster diamond dispersion on the substrate and then drying it is also effective. This pre-treatment method using spin coating can provide the same adhesion effect as the above ultrasonic cleaning method.

Adamantane is a molecule represented by the molecular formula C ₁₀ H ₁₆ and is a sublimable molecular crystal (normal temperature and normal pressure) having the same three-dimensional structure as the basic skeleton of diamond, and is produced by a petroleum refining process. The powder and its derivatives and their multimers are already sold by Idemitsu Kosan Co., Ltd.

  In order to attach adamantane or a derivative thereof or a multimer thereof on a PC resin material, the substance is dissolved in a solvent (for example, ethanol), and then the substrate is immersed in the solution to perform ultrasonic cleaning. After that, the substrate is taken out and dried. In this manner, a PC resin material having adamantane or a derivative thereof or a multimer thereof attached to the surface can be obtained.

  At this time, by reducing the concentration of adamantane or a derivative thereof or a multimer thereof dissolved in a solvent, the adhesion ratio of adamantane or a derivative thereof or a multimer thereof attached to the substrate surface can be reduced. Thereby, the nucleation density of carbon particles can be lowered in the plasma CVD process, and a discontinuous film made of an aggregate of carbon particles can be obtained instead of a continuous film. The surface density of the carbon particles in the aggregate can be controlled by the concentration of adamantane or a derivative thereof or a multimer thereof in the solution. Furthermore, the particle size of the carbon particles can be controlled by the time for performing the plasma CVD process. In addition, by making the concentration very thin, an integrated body made of isolated carbon particles on the substrate can be produced. Furthermore, only the carbon particles can be obtained by removing the substrate from the aggregate by treating the aggregate with an organic solvent or the like.

  In addition, as another method of pretreatment for attaching adamantane or a derivative thereof or a multimer thereof to the substrate, a method of spin-coating the substance solution on the substrate and then drying it is also effective. This pre-treatment method using spin coating can provide the same adhesion effect as the above ultrasonic cleaning method.

In the present invention, the PC resin material is treated using a microwave plasma CVD apparatus, or the PC resin material is pretreated and then treated using a microwave plasma CVD apparatus. Apply.
At this time, in order to prevent the PC resin material from being damaged by the generated plasma, it is necessary to select the raw material gas concentration, molar ratio, reaction time, etc. as operating conditions and operate at a relatively low temperature. Etc. are necessary. In the present invention, the resin material was kept from room temperature to 150 ° C. Holding at such a low temperature is not only effective in preventing plasma damage but also has a remarkable effect of preventing melting and thermal deformation of the resin material. In the present invention, a mixed gas of carbon-containing gas and argon gas and / or hydrogen gas is introduced as a reaction gas into a microwave plasma CVD reactor, and plasma is generated at a gas pressure of 1 to 100 Pascals. The substrate is placed at a position where the plasma electron temperature is 0.5 to 3.0 eV, and the generation origin of the plasma so that the radical particles in the plasma reach the surface of the substrate almost uniformly. This is achieved by adopting a carbon film deposition method in which the film is moved toward the substrate.

The present invention particularly relates to a laminate of a PC resin material and a carbon film formed by holding a PC resin material from room temperature to 150 ° C. and performing a microwave plasma CVD process, and a method for forming the laminate.
Furthermore, by using benzene, acetylene, toluene, methane gas having a high concentration of 10% or more as a carbon source in the source gas, this method can be extended as a method for depositing a diamond-like carbon (DLC) film. Is possible.

About the manufacturing method of the laminated body of this invention, an example is given and an outline is demonstrated below.
After pretreatment such as attaching diamond fine particles by ultrasonic treatment to a polycarbonate (PC) substrate, this is treated with a low-temperature microwave plasma CVD apparatus, and radical particles in the plasma that is the source of film formation, A plasma CVD process is performed by supplying the plasma from a generation source of the plasma toward the substrate so as to reach almost uniformly on the surface of the resin substrate placed on the sample stage.

In the present invention, the raw material gas (reactive gas) used for the CVD process is a mixed gas composed of a carbon-containing gas and argon gas and / or hydrogen. Examples of the carbon-containing gas include methane, ethanol, acetone, methanol and the like.
The mixing ratio of the mixed gas suitable for film formation varies depending on each resin used for the substrate, and also varies depending on the state of the surface treatment of the PC resin, but the concentration of the carbon-containing gas is 0.5 to 10 mol%, Preferably it is 1-4 mol%. If the carbon-containing gas exceeds the above range, problems such as a decrease in light transmittance of the carbon film occur, which is not preferable.
Further, the mixed gas as additive gas, is preferably added to CO ₂ and CO. These gases act as an oxygen source, and exhibit an action of removing impurities in the plasma CVD process. The amount of CO ₂ and / or CO added is preferably 0.5 to 10 mol%, more preferably 1 to 5 mol% in the total mixed gas.
Addition of argon gas and / or hydrogen is extremely effective in preventing plasma damage on the surface of the PC resin material. In particular, when a plasma resistant film is not provided on the surface of the PC resin, increasing the proportion of argon gas compared to the proportion of hydrogen is effective in preventing plasma damage. The proportion of hydrogen gas is suitably 0 to 95.5 mol%, and the proportion of argon gas is suitably 0 to 95.5 mol%.

The plasma CVD processing time is several minutes to several tens of hours, and the processing temperature is 20 to 150 ° C.
In the present invention, the gas pressure of the plasma CVD process and the position where the PC resin base material is disposed are very important, and were confirmed as follows.

FIG. 2 shows an example of an apparatus used for forming a laminate of the carbon film and PC resin of the present invention.
In the figure, 101 is a microwave plasma CVD reactor (hereinafter simply referred to as “plasma generation chamber”), 102 is a rectangular waveguide with a slot for introducing microwaves into the plasma generation chamber 101, and 103 is a microwave. Is a quartz member for introducing the substrate into the plasma generation chamber 101, 104 is a metal support member for supporting the quartz member, 105 is a substrate for film formation, and 106 is a sample stage for installing the film formation substrate, A vertical movement mechanism and a film formation substrate cooling mechanism are provided, and reference numeral 107 denotes a cooling water supply / drainage. Reference numeral 108 denotes exhaust gas, and reference numeral 109 denotes plasma generation gas introduction means. 110 is a reactor for performing plasma CVD processing.

Plasma generation using the apparatus is performed as follows.
The plasma generation chamber 101 is evacuated by an exhaust device (not shown). Subsequently, a plasma generating gas is introduced into the plasma generating chamber 101 through the plasma generating chamber gas introducing means 109 at a predetermined flow rate. Next, a pressure control valve (not shown) provided in the exhaust device is adjusted to maintain the plasma generation chamber 101 at a predetermined pressure. Plasma is generated by supplying a microwave of a desired power from a 2.45 GHz microwave generator (not shown) into the plasma generation chamber 101 through the slotted rectangular waveguide 102 and the quartz member 103. Plasma is generated in the chamber 101. As a result, the microwave introducing quartz member 103, which is the origin of the generation of the plasma, so that the radical particles in the plasma, which is the source of the film formation, reach the surface of the PC resin substrate placed on the sample stage substantially uniformly. It can move toward the substrate from the lower surface (CVD processing reactor side) of the substrate and supply it by downflow.

FIG. 3 shows the distance dependence of the electron temperature (electron kinetic energy) in the plasma from the lower surface of the quartz window for introducing microwaves (on the CVD reactor side) obtained by measuring the plasma characteristics using a Langmuir probe. The Langmuir probe used for the plasma characteristic measurement was a L2P type probe for plasma diagnosis manufactured by Kobe Steel. At this time, in order to accurately measure the plasma density and electron temperature of the electrodeless discharge plasma excited by microwaves, the measurement was performed by a technique called a double probe method using two probes of platinum and tungsten. The Langmuir probe method is described in detail, for example, in the document “Hideo Sakurai, Plasma Electronics, Ohmsha 2000, p.58”.
The gas used for the measurement in this figure is 100% hydrogen and the pressure is 10 Pa. Thus, the electron temperature in the plasma has a characteristic that it decreases as the distance from the quartz window increases. FIG. 4 shows the dependence of the plasma density on the distance from the lower surface (CVD reactor side) of the quartz window for introducing microwaves.
In addition to the above measurements, methane gas 0.5 to 10 mol%, carbon dioxide gas 0 to 10 mol%, hydrogen gas 0 to 95.5 mol%, and argon gas 0 to 95.5 mol% are mixed at any ratio. Electron temperature and plasma density were measured. As a result, the plasma characteristics hardly changed in the measured gas mixing range.

The PC resin substrate is placed on a sample stage that can move up and down so that the PC resin substrate can be placed at an arbitrary position from the quartz window. The electron temperature in the plasma shown in FIG. Based on the plasma density data shown, film formation experiments were performed by changing the position of the PC resin substrate at a gas pressure of 10 Pa, and the optimum electron temperature and plasma density conditions for the film formation were searched.
As a result, it was found that no film was formed at the position of the substrate where the electron temperature was 3 eV or higher, or only a ridge-like film was deposited rather than the carbon film of the present invention. For example, at a pressure of 10 Pa shown in FIG. 5, a region having a distance of 20 mm or less from the quartz window was a region where no film was formed or a ridge-like film was slightly deposited.
On the other hand, the formation of the carbon film of the present invention was confirmed in the region where the electron temperature was 3 eV or less. For example, it was confirmed that the film was formed in an area of 20 mm to 200 mm at a pressure of 10 Pa. When the pressure was 10 Pa, the electron temperature was 3 eV to 0.8 eV in this region.
Since the maximum movable range of the sample stage used in this experiment is 200 mm, the experiment could not be performed at a distance longer than this, but by experimenting with the sample stage, the experiment was performed at a larger distance. Is possible.

  In the region where this film formation was confirmed, the film formation speed reached its maximum when the distance from the quartz window was 50 mm to 70 mm. This is the dependence of the plasma density in FIG. 6 on the distance from the quartz window. Since the plasma density is maximum at 50 mm, it can be explained that the film formation speed becomes maximum at about 50 mm. Therefore, when it is desired to increase the film forming speed as much as possible, it has become clear that the optimal position of the PC resin material for film forming is a position where the electron temperature is 3 eV or less and the plasma density is maximized.

The above experiment was conducted at various gas pressures. As a result, it was found that the gas pressure suitable for the deposition of the carbon film was 1 to 100 Pa, preferably 1 to 50 Pa. When the gas pressure was 200 Pa or higher, film formation could not be confirmed. This is considered to be due to the fact that the heat damage, thermal expansion, and thermal deformation of the PC resin substrate are large due to heating from the plasma because the gas pressure is high. Also, these experiments revealed that the optimal position of the PC resin material for film formation varies depending on the gas pressure in the plasma CVD process. It has been clarified that a carbon film can be deposited on the PC resin material when the PC resin material is arranged at a position where the plasma electron temperature is 0.5 to 3 eV at each gas pressure.
The position of such a PC resin material suitable for film formation can be selected so that the radical particles in the plasma, which is the source of film formation, can reach the surface of the resin substrate placed on the sample stage almost uniformly. By moving from the generation source of the plasma toward the substrate, an electron temperature distribution that gradually decreases from the generation source of the plasma toward the substrate can be formed as shown in FIG. It depends on what was done.

  As a result of observing the carbon film deposited on the PC resin material with an optical microscope as described above, it was found that it is difficult to uniformly form the carbon film on the resin material when the film thickness is 50 nm or less. . When the film thickness is 50 nm or more, a carbon film can be uniformly formed on the PC resin material. However, when the film thickness is 100 nm or more, the carbon film can be formed more uniformly on the PC resin material. Became clear. When the film thickness was 10 μm or more, the deposited carbon film was easily peeled off from the PC resin material. When the film thickness was 5 μm or less, a carbon film having adhesiveness sufficiently withstanding an adhesion strength test using a scotch tape could be formed on the PC resin material. Therefore, the film thickness of the carbon film suitable for forming a laminate of the PC resin material and the carbon film is 2 nm to 100 μm, preferably 50 nm to 10 μm, and more preferably 100 nm to 5 μm.

According to the present invention, a laminate of a carbon film and a resin material can be formed. In the X-ray diffraction spectrum by CuK _α1 ray, this carbon film has a peak fitting curve A of 43.9 ° with a Bragg angle (2θ ± 0.3 °) of 41.7 ± 0.00 mm as seen in FIG. It has a remarkable characteristic different from other carbon particles such as diamond and carbon film, that it has an approximate spectral curve obtained by superimposing a 3 ° peak fitting curve B and a base line.
In addition, in the Raman scattering spectrum (excitation light wavelength 244 nm), as seen in FIGS. 7 to 9, a clear peak is observed in the vicinity of the Raman shift 1333 cm ⁻¹ , and the full width at half maximum (FWHM) is 10 to 40 cm ^−1. It is.

  Further, from observation of the cross section of the film with a high-resolution transmission electron microscope, the film is formed by clogging crystalline carbon particles having a particle diameter of 1 nm to several tens of nm without gaps, and the interface between the film and the substrate, It was found that the particle size distribution in the film and in the vicinity of the outermost surface of the film was not changed (average particle diameter was almost equal). The particle size of the particles is preferably 1 to 100 nm, and more preferably 2 to 20 nm.

The film thus obtained is excellent in flatness and adhesion, and has a surface roughness Ra of 20 nm or less, and in some cases, a flat film reaching 3 nm or less. The adhesion strength was measured with a scratch tester using a diamond needle having a tip diameter of 25 μm, and it was found that a peel load of 30 mN or more was obtained.
The high transparency of the carbon film of the present invention is realized by the above-mentioned film thickness and this surface roughness, and the obtained film is excellent in transparency and has a refractive index of 1.5 or more and birefringence. The optically superior properties such as almost no. In addition, it has excellent electrical properties such as a very high electrical insulating property of 10 ⁷ Ωcm or higher at a temperature of 100 ° C.

EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, this invention is not limited at all by these Examples.
(Deposition of carbon film)
A plate-like polycarbonate (PC) resin was used as the substrate. The shape of the PC resin substrate was 50 mm × 50 mm and the thickness was 2 mm.
These PC resin base materials were subjected to pretreatment for adhering nanocrystal diamond particles dispersed in water. For this purpose, a PC resin substrate was immersed in this dispersion and subjected to an ultrasonic cleaner, and then the substrate was immersed in ethanol for ultrasonic cleaning, and then the substrate was taken out and dried. In this way, a PC resin base material having nanocrystal diamond particles attached to the surface was obtained. Adhesion of the nanocrystal diamond particles to the PC resin base material is due to a part of the particles being embedded in the substrate surface by physical force in ultrasonic cleaning treatment. Diamond particles adhering to the PC resin substrate act as seed crystals for carbon film growth in the plasma CVD process.

Using the plasma CVD apparatus shown in FIG. 2, a carbon film was formed on the PC substrate that had been subjected to the above pretreatment as follows.
The gas used for the CVD treatment was 90 mol% hydrogen, 5 mol% methane gas, and 5 mol% carbon dioxide. Plasma was generated at a gas pressure of 20 Pa, the substrate was placed at a position 50 mm from the quartz window where the electron temperature of the plasma was 1 eV, and plasma CVD treatment was performed for 4 hours. The temperature of the substrate during the plasma CVD process was measured by bringing a thermocouple installed on the sample stage 106 into contact with the back surface of the substrate. The substrate temperature was 120 ° C. throughout the plasma CVD process. By this plasma CVD treatment, a carbon film having a thickness of approximately 1.1 μm was deposited on the surface of the substrate.

FIG. 5 shows the Raman scattering spectrum (excitation light wavelength 244 nm) of the laminate of the PC resin substrate and the carbon film produced by the above method. As can be seen from FIG. 5, a peak located in the vicinity of the Raman shift of 1333 cm ⁻¹ is clearly recognized in the Raman scattering spectrum of the laminate, and it is clear that a carbon film is deposited. As a result of measuring in the same manner for many other samples prepared by this method, it was found that this peak was in the range of 1320 to 1340 cm ^-1 and was always in the range of 1333 ± 10 cm ^-1 . . In addition, the broad peak seen in the vicinity of the Raman shift of 1600 cm ⁻¹ indicates the presence of the sp ² bond component of carbon. The full width at half maximum (FWHM) of the peak located near the Raman shift of 1333 cm ⁻¹ was about 22 cm ⁻¹ .
As a result of the same measurement for many other samples, it was found that the FWHM was in the range of 10 to 40 cm- ¹ .

(Measurement of surface roughness)
The surface roughness was evaluated by observing the surface of the carbon layer of the PC laminate of the present invention with an atomic force microscope (AFM). In this case, in order to suppress the influence of the surface roughness of the substrate on the surface roughness of the film as low as possible, a carbon layer is formed on a mirror-polished polycarbonate substrate having a small surface roughness (diameter 10 mm × thickness 3 mm), A sample for measurement was obtained. The AFM apparatus used was a Nanoscope scanning probe microscope manufactured by Digital Instruments, USA, and a cantilever single crystal silicon rotation probe Tap300 for scanning probe microscope manufactured by Veeco Instruments was used as the cantilever. Tapping mode was used for measurement, and observation was performed at a scan size of 1 μm × 1 μm and a scan rate of 1.0 Hz. As a result, it was confirmed that the surface roughness of the carbon layer was in the range of 3 to 20 nm in terms of Ra, although the surface roughness varied depending on the deposition conditions of the carbon layer. The arithmetic average height Ra is described in detail in, for example, “JIS B 0601-2001” or “ISO4287-1997”.

(X-ray diffraction of carbon film)
The laminate of the carbon film of the present invention and the PC resin was observed by X-ray diffraction. Details of the measurement are described below.
The X-ray diffractometer used was Rigaku Corporation's X-ray diffractometer RINT2100 XRD-DSCII, and the goniometer was a Rigaku Ultima III horizontal goniometer. A multipurpose sample stand for thin film standard is attached to this goniometer. The measured sample is a carbon film having a thickness of 500 nm deposited on a PC resin substrate having a thickness of 2 mm according to the present invention. What cut out to 30 mm square with the PC resin base material was measured. As the X-ray, copper (Cu) _Kα1 ray was used. The applied voltage / current of the X-ray tube was 40 kV / 40 mA. A scintillation counter was used as the X-ray detector. First, the scattering angle (2θ angle) was calibrated using a silicon standard sample. The deviation of the 2θ angle was + 0.02 ° or less. Next, the measurement sample is fixed to the sample stage, and the 2θ angle is 0 °, that is, the X-ray incident direction is parallel to the sample surface under the condition that the X-ray is directly incident on the detector. It was adjusted so that half was blocked by the sample. The goniometer was rotated from this state, and X-rays were irradiated at an angle of 0.5 degrees with respect to the sample surface. The incident angle was fixed, the 2θ angle was rotated from 10 ° to 90 ° in steps of 0.02 °, and the intensity of X-rays scattered from the sample at each 2θ angle was measured. The computer program used for the measurement is RINT2000 / PC software Windows (registered trademark) version manufactured by Rigaku Corporation.

The measured X-ray diffraction spectrum is shown in FIG. White circles in the figure are measurement points. It can be seen that there is a clear peak at 2θ of 43.9 °. What is interesting here is that, as can be seen from FIG. 6, the peak at 43.9 ° has a shoulder at the low angle side, 2θ of 41 to 42 °. (For the “shoulder” of the spectrum, refer to “Chemical Dictionary” (Tokyo Kagaku Dojin).) Therefore, this peak is a peak centered around 43.9 ° (first peak) and 41 to 42 °. Another peak (second peak) distributed around is composed of two component peaks. Diamond is known as a carbon-based material having a peak at 2θ of 43.9 ° by X-ray diffraction using CuK _α1 rays. Here, FIG. 7 is a spectrum obtained by X-ray diffraction measurement of diamond by the same method, and the peak is due to (111) reflection of diamond. The difference in the X-ray diffraction spectrum between the carbon film of the laminate of the present invention and diamond is clear, and the second peak distributed around 41-42 ° seen in the spectrum of the carbon film of the laminate of the present invention is I can't see it. Thus, the (111) reflection of diamond is composed of one component (only the first peak) centered at 43.9 °, and the shoulder on the low angle side like the carbon film of the laminate of the present invention is not observed. Therefore, the second peak distributed around 41 to 42 ° seen in the spectrum of the carbon film of the laminate of the present invention is a characteristic peak of the carbon film of the laminate of the present invention.

  Further, it can be seen that the peak of the X-ray diffraction spectrum of the carbon film of the laminate of the present invention in FIG. 6 is very wide compared to the peak of diamond in FIG. In general, when the size of the particles constituting the film is reduced, the width of the X-ray diffraction peak is increased, and it can be said that the size of the particles constituting the carbon film of the laminate of the present invention is very small. When the size (average diameter) of the carbon particles constituting the carbon film of the laminate of the present invention is estimated from the width of the peak by Scherrer's formula usually used in X-ray diffraction, it is about 15 nm. It was. For the Scherrer formula, refer to, for example, “Thin Film Handbook edited by Japan Society for the Promotion of Science, Thin Film 131st Committee, Ohmsha 1983, p. 375”.

Next, details of the configuration of the peak (position and intensity of each peak component, etc.) will be seen.
In order to know the detailed configuration of the peak at 2θ of 43.9 ° in the X-ray diffraction measurement of the carbon film of the laminate of the present invention, the 2θ angle was between 39 ° and 48 °, and analysis was performed using peak fitting. . A function called a Pearson VII function was used for fitting the first peak. This function is most commonly used as a peak profile of diffraction methods such as X-ray diffraction and neutron diffraction. As for the Pearson VII function, it is recommended to refer to “Practice of Powder X-ray Analysis—Introduction to Rietveld Method” (edited by the Japan Society for Analytical Chemistry X-ray Analysis Research, Asakura Shoten) Further, as a result of examining various functions, it has been found that an asymmetric function should be used for fitting the second peak. Here, an asymmetric normal distribution function (Gaussian distribution function) was used. This function is a normal distribution function with different dispersion (standard deviation) values on the right and left sides of the peak position, and is one of the simplest functions used for fitting asymmetric peaks, but very well peak fitting I was able to. A linear function (linear function) was used as the baseline (background) function.

  Although various computer programs can be used for the actual fitting work, the ORIGIN version 6 Japanese version peak fitting module (hereinafter ORIGIN-PFM) was used here. In ORIGIN-PFM, the Pearson VII function is expressed as “Pearson7”, the asymmetric normal distribution function as “BiGauss”, and the linear function as “Line”. The fitting completion condition was that the correlation coefficient (ORIGIN-PFM “COR” or “Corr Coef”) representing the fitting reliability was 0.99 or more.

  As a result of analysis using this peak fitting, as shown in FIG. 6, this measured spectrum has a first peak by the Pearson VII function (fitting curve A in the figure), a second peak by the asymmetric normal distribution function (fitting curve B in the figure), And it was found that the sum of the baseline (background) by the linear function (fitting total curve in the figure) can be approximated very well. In this measurement, the center of the fitting curve A is 2θ at 43.9 °, whereas the fitting curve B is maximum at 41.7 °. The area surrounded by each fitting curve and the baseline is the intensity of each peak. Thus, the intensity of the second peak relative to the intensity of the first peak was analyzed. In the case of this sample, the intensity of the second peak (fitting curve B) was 45.8% of the intensity of the first peak (fitting curve A).

  When many samples of the carbon film of the laminate of the present invention were subjected to X-ray diffraction measurement, a wide peak as shown in FIG. 6 was observed with 2θ centering on 43.9 ° in all samples. In addition, it has a shape with a shoulder on the low angle side as shown in FIG. 6 and is composed of a first peak and a second peak. When analysis by the same peak fitting was performed on X-ray diffraction spectra measured on a large number of samples, it was found that fitting was possible very well using the above-described function. The center of the first peak had 2θ of 43.9 ± 0.3 °. The second peak was found to be maximum when 2θ was 41.7 ± 0.3 °. The intensity ratio to the first peak was 5% minimum and 90% maximum. This intensity ratio is highly dependent on the synthesis temperature, and tends to increase as the temperature decreases. On the other hand, the position of the peak was almost constant regardless of the synthesis temperature.

  It should be noted that this X-ray diffraction measurement analysis method has a large variation in measurement data if the intensity of the X-ray is small, and reliable fitting is impossible. For this reason, it is necessary to perform the above-described analysis by fitting for those whose peak maximum intensity is 5000 counts or more.

As described above, the carbon film of the laminate of the present invention has a wide peak with 2θ centering on 43.9 ° in the X-ray diffraction measurement by CuK _α1- ray, and the peak is a shoulder on the low angle side. It became clear that it had a certain structure. As a result of analysis using peak fitting, this peak is derived from the first peak from the Pearson VII function centered at 2θ of 43.9 °, the second peak from the asymmetric normal distribution function having the maximum at 41.7 °, and a linear function. It was found that the approximation of the baseline (background) can be approximated very well.

  Similar analysis by peak fitting was performed on the spectrum of diamond shown in FIG. It was found that, unlike the above-described carbon film of the laminate of the present invention, in the case of diamond, it can be approximated very well only by the Pearson VII function centered at 2θ of 43.9 °. Therefore, it was found that the carbon film of the laminate of the present invention is a substance having a structure different from that of diamond.

  The carbon film of the laminate of the present invention is characterized in that the second peak described above is observed, and is a carbon film having a structure different from that of diamond. The manufacturing process of the carbon film of the laminate of the present invention and other measurement results were examined, and the structure was examined. When the method for synthesizing the carbon film in the laminate of the present invention is compared with the CVD method for diamond, it has the following significant features. First, normal diamond synthesis is performed at a temperature of at least 700 ° C., whereas the carbon film of the laminate of the present invention is synthesized at a very low temperature. Conventionally, when the particle diameter of the diamond film is reduced, a method of growing at a high speed with a high concentration of about 10% of the carbon source concentration (methane gas molar ratio) contained in the source gas has been used. The concentration is as low as 1%. That is, in this method, carbon particles are deposited and a film is formed by taking time very slowly at a low temperature. Therefore, the carbon particles are deposited in a state where it is possible to become diamonds. For this reason, a force that promotes the precipitation of hexagonal diamond, which is a crystal made of carbon that is more stable than ordinary cubic diamond, and the precipitation of more stable graphite works, and the crystal deposition state is very unstable. Further, once precipitated graphite and amorphous carbon material are also removed by etching with hydrogen plasma contained in the source gas. By such a precipitation mechanism, cubic diamond and hexagonal diamond are mixed and a portion removed by etching remains as a very high concentration defect. These defects include point defects such as atomic vacancies, linear defects such as dislocations, and a large amount of surface unit defects such as stacking faults. Therefore, the X-ray diffraction peak at 43.9 ° has a shoulder on the low angle side.

  However, the characteristics of the X-ray diffraction peak as described above are linked to the high function of the carbon film of the laminate of the present invention. That is, because of the low-speed synthesis at a low carbon source concentration, the etching of graphite and graphite-like materials is promoted, resulting in a structure containing a high concentration of defects, while the thermal conductivity, strength, and hardness of the carbon film. And keeping transparency high. In addition, because it is synthesized at a low temperature, cubic diamond and hexagonal diamond are mixed and contain a high concentration of defects, but the low temperature can also cause thermal damage to the resin material. Without direct coating. Furthermore, because of the synthesis at a low temperature, the carbon particles in the carbon film have a uniform particle size, and the strain due to heat is very small. That is, a structure in which cubic diamond and hexagonal diamond are mixed and contains a very high concentration of defects has the characteristics that thermal distortion is relaxed and optical birefringence is small. Similarly, thanks to this structure, a very high electrical insulation is exhibited.

(Measurement of electrical resistance and Hall effect of carbon film)
In order to know the electrical characteristics of the carbon film of the laminate of the present invention, electrical resistance measurement and Hall effect measurement were performed. Details of the measurement are described below. The electrical resistance measuring device and Hall effect measuring device used are ResiTest8310S type machines manufactured by Toyo Technica. The sample holder used is a VHT type manufactured by Toyo Technica. The measured sample is a carbon film having a thickness of 500 nm prepared on a PC resin substrate having a thickness of 2 mm by the method of the present invention. What cut into 4 mm square with the PC resin base material was measured. As an electrode, Ti was deposited to a thickness of 50 nm in a circle having a diameter of 0.3 mm by vacuum evaporation at four corners of the sample. Further, 50 nm of Pt and 100 nm of Au were deposited thereon to prevent oxidation of the Ti electrode. This was attached to a sample table made of high resistance alumina, and wiring was performed by ultrasonic bonding of a φ250 μm gold wire to the electrode.
The electrical resistance measurement was performed in an atmosphere of 1 mbar helium. Performed at room temperature and 100 ° C. Consequently 100 ° C. In the 1 × 10 ⁹ Ωcm or more, exhibited at room temperature (20 ° C.) in the 1 × ^{10 10} Ωcm or more high resistance value.
Although an attempt was made to determine the type of electrical conductivity by measuring the Hall effect, it was not possible to determine whether it was p-type or n-type due to high resistance.
The electrical properties as described above indicate that the carbon film of the laminate of the present invention functions as a very good electrical insulating film.

(Measurement of thermal conductivity of carbon film)
The heat conduction of the carbon film formed on the PC resin substrate of the present invention was measured using a laser flash method. In this measurement method, it is difficult to measure thermal conductivity in a state where a carbon film is deposited on a PPS resin base material, and therefore, quartz glass was used as the base material. A carbon film was deposited on a quartz glass substrate, and the thermal conductivity of the carbon film was evaluated. A carbon film having a thickness of 1 μm was formed on a quartz glass substrate having a size of 5 mm × 5 mm and a thickness of 100 μm. 30 samples were stacked to prepare a rectangular parallelepiped sample having a size of 5 mm × 5 mm and a side surface thickness of about 3 mm. The side surface having a thickness of about 3 mm was irradiated with an infrared laser, and the thermal diffusivity in the in-plane direction of the quartz glass on which the carbon film was formed was determined by a laser flash method. The infrared laser irradiation surface was subjected to blackening treatment in order to enhance absorption of infrared light. (In the measurement and data analysis by the laser flash method used in this example, the latest thermal measurement was applied from the basics to the application (supervised by Ichiro Hatta, edited by ULVAC-RIKO, Agne Technology Center). .) At the same time, a rectangular parallelepiped sample in which only 30 quartz glass substrates without a carbon film were similarly stacked was prepared, and the thermal diffusivity of only the quartz glass substrate was measured. From the above measurements, the thermal diffusivities of the quartz glass substrate with the carbon film and the quartz glass substrate without the carbon film were compared, and the thermal diffusivity at 25 ° C. in the in-plane direction of only the carbon film was obtained. The specific heat and density of the carbon film of this laminate were measured. By multiplying these by the thermal diffusivity, a thermal conductivity of 30 W / mK or more was obtained for the carbon film of the present invention.

(Evaluation of optical properties)
The light transmittance of the carbon film formed on the PC resin substrate of the present invention was evaluated. The equipment and settings used for the measurement are as follows.
Measuring apparatus: UV-3101PC type self-recording spectrophotometer manufactured by Shimadzu Corporation Slit width: 30 nm
Slit program: Normal Light source: Halogen lamp (340nm or more), Hydrogen lamp (340nm or less)
Detector: PMT (860 nm or less), PbS (860 nm or more)
Secondary white board: BaSO4
Incident angle: 0 °
FIG. 8 is a diagram showing the wavelength dependence of the visible light transmittance of the laminate of the carbon film and the PC resin of the present invention. The film thickness of the carbon film was approximately 1.1 μm. In the figure, the visible light transmittance of only a PC resin base material without a carbon film is also shown for comparison. The average visible light (400-800 nm) transmittance of the laminate of the carbon film and the PC resin was 82.7%. Thus, it turned out that the laminated body of the carbon film and PC resin of this invention has sufficient transparency.

  Since the laminate of the carbon film and the PC resin of the present invention has the above-described characteristics, it can not be applied to an industrial field where visible light transmittance and chemical resistance are required, which cannot be applied with a conventional PC resin. Is possible. For example, it can be applied to a container made of a PC resin for chemicals that requires visual confirmation of the contents, or can be used in a severe environment where the PC resin material deteriorates.

Sectional drawing which shows the outline | summary of the laminated body of the carbon film and PC resin of this invention. The figure which shows the structure of the manufacturing apparatus of the laminated body of the carbon film and PC resin of this invention. The figure which shows the distance dependence from the lower surface (CVD reactor side) of the quartz window for microwave introduction of the electron temperature (electron kinetic energy) in the plasma obtained by the plasma characteristic measurement using a Langmuir probe. The figure which shows the distance dependence from the lower surface (CVD reactor side) of the quartz window for microwave introduction of plasma density. The Raman spectrum figure which shows carbon film formation to PC resin base material. The figure which shows the X-ray-diffraction spectrum by a CuK ( _{alpha) 1} X-ray of the carbon film of an example of this invention, and a peak fitting result. The figure which shows the typical X-ray-diffraction spectrum ((111) reflection peak) by CuK ( _{alpha) 1} X-ray in a diamond, and a peak fitting result. The figure which shows the wavelength dependence of the visible light transmittance | permeability of the laminated body of the carbon film and PC resin of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Plasma generation chamber 102 Square waveguide with a slot 103 Quartz member for microwave introduction 104 Metal support member which supports a quartz member 105 Film-forming base material 106 Sample stage for installing a film-forming base material 107 Supply / drainage of cooling water 108 Exhaust 109 Gas introducing means for generating plasma 110 Reactor

Claims (4)

A polycarbonate resin material and a carbon film having a film thickness of 50 nm to 10 μm and a surface roughness Ra of 20 nm or less deposited on the surface of the polycarbonate resin material, the carbon film having an X-ray diffraction spectrum by CuK _α1 rays A polycarbonate laminate comprising a spectral peak at 41 to 42 ° with a Bragg angle (2θ ± 0.3 °).   2. The polycarbonate laminate according to claim 1, wherein the light transmittance at a wavelength of 400 to 800 nm is 55% or more.   The polycarbonate laminated body of Claim 1 whose light transmittance in wavelength 500-800nm is 80% or more. The polycarbonate laminate according to any one of claims 1 to 3, which has a thermal conductivity of 30 W / mK or more and a resistance value of 1 x 10 ⁷ Ωcm or more (100 ° C).

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