JP4829036B2 - Translucent laminate - Google Patents

Description

  The present invention relates to a translucent laminate.

  In general, resins such as polycarbonate and polymethylmethacrylate have low resistance to ultraviolet rays, and are therefore likely to cause discoloration, deformation, and strength reduction due to sunlight. Therefore, conventionally, a means for preventing deterioration due to ultraviolet rays has been sought for exterior members such as automobiles which are made of such a resin and are mainly used outdoors. For example, Patent Documents 1 and 2 disclose a method of forming a protective film on the surface of an automotive plastic part by plasma CVD (Chemical Vapor Deposition). According to these methods, it is possible to form a protective film excellent in scratch resistance in addition to ultraviolet blocking properties.

However, the silicon oxide-based material used in Patent Document 1 and the zinc oxide-based material used in Patent Document 2 as the material for the protective film have insufficient adhesion to the base material, and are further improved. There is room for. Therefore, a method of adopting titanium oxide as a material for the protective film can be considered. Titanium oxide is suitable as a protective film for resin members mainly used outdoors because it has excellent ultraviolet blocking properties and high water resistance. As a surface treatment method using titanium oxide as a material for a coating film of a resin base material, the one described in Patent Document 3 can be mentioned. According to Patent Document 3, as a specific coating film, a coating film formed by alternately laminating silicon oxide layers and titanium oxide layers is disclosed.
JP 2000-345347 A JP 2002-260412 A JP 2004-35941 A

  However, the present inventors have made a detailed study of the conventional technique described in Patent Document 3, and as a result, even the coating film described in Patent Document 3 has insufficient adhesion to the base material. It was found that it easily peels from the material. Moreover, the present inventors have found that the coating film described in Patent Document 3 significantly reduces the transparency when formed on a light-transmitting substrate.

  Therefore, the present invention has been made in view of the above circumstances, and an object thereof is to provide a translucent laminate in which peeling of a protective film from a substrate is sufficiently suppressed and has sufficiently high transparency. To do.

In order to achieve the above object, the present invention includes a translucent base material, and a first protective film formed on the main surface of the translucent base material by a plasma CVD method and mainly composed of titanium oxide. The first protective film provides a translucent laminate that satisfies the condition represented by the following formula (1).
6% ≦ A _C / (A _Ti + A _O + A _C ) × 100 ≦ 15% (1)
Here, in the formula (1), A _C is contained mass containing a mass of carbon atoms in the first protective film, A _Ti is contained mass of titanium atoms in the first protective film, A _O is oxygen atom in the first protective film Respectively.

  The protective film made of titanium oxide itself is poor in flexibility, and changes the base material in contact with the protective film due to the photocatalytic ability of titanium oxide. As a result, the protective film is easily peeled off from the base material, and the transparency of the base material is lowered. In order to prevent deterioration of the base material, a means for providing a film made of silicon oxide between the base material and a protective film made of titanium oxide can be considered. However, in this case, since the adhesion of the film made of silicon oxide to the base material is not high, the protective film is easily peeled off.

  On the other hand, the translucent laminate of the present invention described above sufficiently prevents the protective film from peeling off by setting the content mass of carbon atoms in the first protective film mainly composed of titanium oxide to a specific amount within the above range. In addition, a sufficiently excellent transparency can be ensured. The first protective film can be sufficiently prevented from being peeled off by using the plasma CVD method to improve the adhesion of the first protective film to the translucent substrate, and titanium oxide as a main component of the first protective film. By incorporating a specific amount of carbon atoms, the first protective film can be provided with appropriate flexibility and a thin film with a higher proportion of amorphous parts, so that the photocatalytic ability of titanium oxide can be reduced. It is thought to be caused by. In addition, sufficiently excellent transparency can be ensured by forming the first protective film mainly composed of titanium oxide using the plasma CVD method, and sufficiently reducing the light scattering property of the first protective film. It is considered that the coloring caused by the carbon atom can be sufficiently suppressed by keeping the contained mass of the carbon atom within a specific range. However, the factors are not limited to these.

  In the translucent laminate of the present invention, since the first protective film sufficiently blocks light having a wavelength in the ultraviolet region, the translucent substrate can be sufficiently prevented from being deteriorated by ultraviolet rays. In addition, since the first protective film can sufficiently transmit light in the visible light region, the translucent laminate of the present invention is sufficiently useful as a lens for a vehicle lamp. Moreover, since the first protective film has moderate flexibility, it is difficult for cracks to occur. Furthermore, since the 1st protective film which concerns on this invention is excellent also in a weather resistance, when it uses for the member used outdoors, it is effective. Further, since the first protective film is formed by the plasma CVD method, the film thickness is uniform and can be thinned as compared with a protective film formed by a wet film forming method such as a spray method. Since it is not necessary to use an organic solvent, it is excellent from the viewpoint of environmental protection.

  The translucent laminate of the present invention further includes a second protective film formed on the main surface opposite to the translucent substrate of the first protective film by a plasma CVD method and mainly composed of silicon oxide. preferable. Thereby, the weather resistance and scratch resistance of the translucent laminate are further improved. Further, since the second protective film also has an ultraviolet absorbing ability, the ultraviolet blocking property of the protective film is further improved.

The second protective film preferably satisfies the condition represented by the following formula (2).
6% ≦ B _C / (B _Si + B _O + B _C ) × 100 ≦ 20% (2)
Here, in Formula (2), B _C is the mass content of carbon atoms in the second protective film, B _Si is the mass content of silicon atoms in the second protective film, and B 2 _O is the mass content of oxygen atoms in the second protective film. Respectively.

  This translucent laminate prevents the peeling of the second protective film from the first protective film by setting the mass content of carbon atoms in the second protective film containing silicon oxide as a main component to a specific amount within the above range. In addition, excellent transparency can be secured. The second protective film can be prevented from being peeled off by using the plasma CVD method so that the adhesion of the second protective film to the first protective film can be improved, and silicon oxide is adopted as the main component of the second protective film. In addition, it is considered that by including a specific amount of carbon atoms, an appropriate flexibility can be imparted to the second protective film. In addition, excellent transparency can be ensured by forming a second protective film mainly composed of silicon oxide using a plasma CVD method so that the light scattering property of the second protective film can be sufficiently reduced, and carbon It is considered that the coloration caused by the carbon atoms can be sufficiently suppressed by keeping the atomic mass within a specific range. Furthermore, this translucent laminate has excellent scratch resistance because the second protective film itself exhibits high scratch resistance, and the highly flexible first protective film is used as the translucent substrate. It is considered that the first protective film plays a role of a cushion by being provided between the first protective film and the second protective film. However, the factors are not limited to these.

  In addition, since the second protective film has a thermal expansion coefficient that is close to that of the first protective film, high adhesion to the first protective film is maintained in a wide temperature range. Furthermore, since the second protective film has appropriate flexibility, it is difficult for cracks to occur.

  In the translucent laminate of the present invention, it is preferable that the second protective film has a residual stress of 6000 MPa or less. Thereby, since the stress applied to the translucent base material and the first protective film from the second protective film is relieved, the mechanical strength such as impact resistance of the translucent laminate is further increased. Here, the “residual stress” is measured by, for example, a commercially available stylus type surface shape measuring instrument.

  In the translucent laminate of the present invention, it is preferable that the first protective film has a thickness of 0.3 to 1.0 μm and the second protective film has a thickness of 0.75 to 2.0 μm. Thereby, the deterioration of the translucent substrate in the translucent laminate is more sufficiently suppressed, and the weather resistance and scratch resistance are further improved, and the mechanical strength of the translucent laminate is improved, and the translucency is improved. Peeling between the substrate and the first protective film and between the first protective film and the second protective film is further effectively suppressed. Moreover, it becomes possible to hold down the manufacturing cost of this translucent laminated body.

  ADVANTAGE OF THE INVENTION According to this invention, peeling of the protective film from a base material can fully be suppressed, and the translucent laminated body which has sufficiently high transparency can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as necessary. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a schematic cross-sectional view showing a translucent laminate according to a preferred embodiment of the present invention. The translucent laminate 1 includes a translucent substrate 10, a first protective film 20 provided on the main surface of the translucent substrate 10, and the translucent substrate 1 of the first protective film 20. And a second protective film 30 provided on the opposite main surface.

  The translucent substrate 10 has a shape suitable for use as a lens (cover) for a vehicular lamp such as an automobile. The material is not particularly limited as long as it can transmit visible light. Specific examples of the material include resin or glass such as quartz glass. Resin is suitably used because it is easy to process and handle, has high impact resistance, and is lightweight. As the resin, for example, polycarbonate and / or polymethyl methacrylate are preferable.

The first protective film 20 contains titanium oxide (TiO ₂ ) as a main component and further contains carbon atoms. In the present embodiment, since the first protective film 20 is formed by a plasma CVD method to be described later, most of the first protective film 20 is amorphous, but some titanium oxide microcrystals (rutile type, anatase type) are mixed. Sometimes it is. The first protective film 20 is sufficiently excellent in ultraviolet blocking properties, has high adhesion (peeling resistance) to the translucent substrate 10, and is excellent in crack resistance of the film itself. Furthermore, it contributes to the improvement of adhesion with the second protective film 30 described later.

The form of carbon atoms contained in the first protective film 20 depends on the raw material used in the plasma CVD method, and may be, for example, carbon atoms in a hydrocarbon gas such as an alkoxy group, an alkyl group, or ethylene gas. The first protective film 20 has a carbon atom content ratio R1 that satisfies the condition represented by the following formula (1a).
6% ≦ R1 ≦ 15% (1a)
Here, R1 is a value that satisfies the condition represented by the following formula (I).
R1 = A _C / (A _Ti + A _O + A _C ) × 100 (I)
Wherein (I), _{A C} is contained mass of carbon atoms in the first protective film _{20, A Ti} is contained mass of titanium atoms in the first protective film 20, _{A O} is contained mass of oxygen atoms in the first protective layer 20 Respectively.

  When the content ratio R1 is less than 6%, the flexibility of the first protective film 20 is reduced, and the first protective film 20 is easily peeled from the translucent substrate 10, so that the protective film such as an ultraviolet blocking property can be used. The function cannot be performed sufficiently. In addition, when the content ratio R1 is less than 6, when the material of the translucent substrate 10 is a resin, the thermal expansion coefficient of the first protective film 20 is significantly smaller than the thermal expansion coefficient of the translucent substrate 10. Therefore, the first protective film 20 tends to be easily peeled off as the temperature changes. Furthermore, when the content ratio R1 is less than 6%, the titanium oxide in the first protective film 20 effectively functions as a photocatalyst for the alteration of the translucent substrate 10. In particular, when the material of the translucent substrate 10 is a resin, titanium oxide significantly functions as a photocatalyst. Therefore, coloring and cracking of the translucent substrate 10 and peeling of the first protective film 20 tend to occur easily.

  On the other hand, if the content ratio R1 exceeds 15%, the brittleness of the first protective film 20 becomes high and the mechanical strength becomes insufficient, so that the first protective film 20 tends to be peeled off or cracked easily. On the other hand, when the content ratio R1 exceeds 15%, the first protective film 20 is remarkably colored, so that it becomes difficult to sufficiently transmit visible light.

Moreover, it is preferable that the 1st protective film 20 satisfies the conditions represented by following formula (1b) from a viewpoint of suppressing peeling and a crack further.
10% ≦ R1 ≦ 14% (1b)

  The film thickness of the first protective film 20 is preferably 0.3 to 1.0 μm, and more preferably 0.4 to 0.7 μm. When this film thickness is less than 0.3 μm, the ultraviolet absorbing ability of the first protective film 20 is lowered, and coloring and embrittlement due to alteration of the translucent substrate 10 and peeling of the first protective film 20 occur. It tends to be easier. Further, when the film thickness exceeds 1.0 μm, the stress tends to increase, and the manufacturing cost tends to increase even though the translucent laminate 1 has sufficient characteristics. is there.

  The residual stress of the first protective film 20 is preferably 6000 MPa or less, and more preferably 3000 MPa or less. When this residual stress exceeds 6000 MPa, the stress applied to the translucent substrate 10 from the first protective film 20 increases, and therefore mechanical strength such as impact resistance of the translucent laminate 1 tends to decrease. .

  The residual stress of the first protective film 20 is a stress curve derived from a cross-sectional curve of a silicon substrate and a cross-sectional curve of a laminate obtained by forming the first protective film 20 on the silicon substrate. Derived from the difference.

  When the first protective film 20 is provided on the surface of the translucent substrate 10, the degree of coloring and cracking of the first protective film 20 itself and the peeling of the first protective film 20 from the translucent substrate 10 Haze is used to assess the degree. The haze of the first protective film is derived by using the haze of the translucent substrate 10 and the haze of the laminated body composed of the translucent substrate 10 and the first protective film 20. When the first protective film 20 has a haze of 0 to 2%, preferably 0 to 1%, the transparency is further sufficient, and the translucent laminate 1 can exhibit its function more effectively. .

  In addition, in the 1st protective film 20, other components other than a titanium oxide and a carbon atom are added in the range which does not inhibit the effect of this invention, and the specific effect by the thing which provides the 1st protective film 20. Also good. Examples of such components include zinc, nitrogen, sulfur, silicon, lead and chlorine.

The second protective film 30 contains silicon oxide (SiO ₂ ) as a main component, and further contains carbon atoms. In the present embodiment, since the second protective film 30 is formed by a plasma CVD method to be described later, most of the second protective film 30 is amorphous, but some silicon oxide microcrystals may be mixed. The second protective film 30 is very excellent in scratch resistance, has high ultraviolet blocking properties, and is excellent in crack resistance of the film itself.

The form of carbon atoms contained in the second protective film 30 depends on the raw material used in the plasma CVD method, and may be, for example, a carbon atom in a hydrocarbon gas such as an alkoxy group, an alkyl group, or ethylene gas. . The second protective film 30 preferably has a carbon atom content ratio R2 that satisfies the condition represented by the following formula (2a).
6% ≦ R2 ≦ 20% (2a)
Here, R2 is a value that satisfies the condition represented by the following formula (II).
R2 = B _C / (B _Si + B _O + B _C ) × 100 (II)
Wherein (II), _{B C} is contained mass containing a mass of carbon atoms in the second protective film _30, the _{B Si} content mass of silicon atoms in the second protective film 30, _{B O} is oxygen atom in the second protective film 30 Respectively.

  When the content ratio R2 is less than 6%, the flexibility of the second protective film 30 is reduced, and the second protective film 30 is easily peeled off from the first protective film 20, so that the function as a protective film such as scratch resistance is achieved. Cannot be fulfilled sufficiently. Further, if the content ratio R2 is less than 6%, the difference in the coefficient of thermal expansion between the first protective film 20 and the second protective film 30 becomes large, so that the second protective film 30 easily peels off as the temperature changes. There is a tendency.

  On the other hand, if the content ratio R2 exceeds 20%, the brittleness of the second protective film 30 becomes high and the mechanical strength becomes insufficient, so that the second protective film 30 tends to be easily peeled off or cracked. On the other hand, if the content ratio R2 exceeds 20%, the second protective film 30 is remarkably colored, so that it is difficult to sufficiently transmit visible light.

Moreover, it is preferable that the 2nd protective film 30 satisfies the conditions represented by following formula (2b) from a viewpoint which suppresses coloring, peeling, and a crack further.
7% ≦ R2 ≦ 15% (2b)

The carbon atom content R2 in the second protective film 30 preferably satisfies the condition expressed by the following formula (3a) with respect to the carbon atom content R1 in the first protective film 20, and the following formula (3b) It is more preferable that the condition represented by Thereby, since the thermal expansion coefficient of the 1st protective film 20 and the 2nd protective film 30 can be brought closer, the peeling and the crack of the 2nd protective film 30 by a temperature change can be reduced further.
0% ≦ | R2-R1 | ≦ 14% (3a)
1% ≦ | R2-R1 | ≦ 7% (3b)

  The film thickness of the second protective film 30 is preferably 0.5 μm or more, more preferably 0.75 to 2.0 μm, and further preferably 0.8 to 1.2 μm. When this film thickness is less than 0.5 μm, the ultraviolet absorbing ability of the second protective film 30 is lowered, and coloring and embrittlement due to alteration of the translucent substrate 10 and peeling of the first protective film 20 occur. It tends to be easier. Further, when the film thickness is less than 0.75 μm, the scratch resistance tends to be lowered. On the other hand, when the thickness of the second protective film 30 exceeds 2.0 μm, the stress tends to increase, and the manufacturing cost is high even though the translucent laminate 1 has sufficient characteristics. Tend to be higher.

  The residual stress of the second protective film 30 is preferably 6000 MPa or less. When this residual stress exceeds 6000 MPa, the stress applied from the second protective film 30 to the first protective film 20 and the translucent substrate 10 increases, so that the mechanical strength such as impact resistance of the translucent laminate 1 is increased. Tend to decrease.

  The residual stress of the second protective film 30 includes a stress curve derived from a cross-sectional curve of a laminate obtained by forming the first protective film 20 on the silicon substrate, and a second protection further on the first protective film 20. It is derived from the difference from the stress curve derived from the cross-sectional curve of the laminate obtained by forming the film 30.

  When the second protective film 30 is provided on the surface of the first protective film 20, the degree of coloring and cracking of the second protective film 30 itself and the degree of peeling of the second protective film 30 from the first protective film 20 are set. Haze is used to evaluate. The haze of the second protective film 30 is derived using the haze of the laminate composed of the translucent substrate 10 and the first protective film and the haze of the translucent laminate 1. When the haze of the second protective film 30 is 0 to 2%, preferably 0 to 1%, the transparency is further sufficient, and the translucent laminate 1 can exhibit its function more effectively. .

  In addition, in the 2nd protective film 30, other components other than a silicon oxide and a carbon atom are added in the range which does not inhibit the effect of this invention, and the peculiar effect by providing the 2nd protective film 30. Also good. Examples of such components include zinc, nitrogen, sulfur, titanium, lead and chlorine.

  Next, the manufacturing method of the translucent laminated body 30 which concerns on this embodiment is demonstrated. The translucent laminate 30 includes a step of forming the first protective film 20 on the main surface of the translucent substrate 10 by a plasma CVD method (first protective film forming step), and further, the main of the first protective film 20. It is manufactured by a manufacturing method including a step of forming a second protective film 30 on the surface by a plasma CVD method (second protective film forming step).

  FIG. 2 is a schematic view of the plasma CVD apparatus according to the present embodiment. This plasma CVD apparatus is provided with a reaction chamber 11 connected to a vacuum exhaust pipe 5 connected to a vacuum pump (not shown) and capable of bringing the inside into a high vacuum state. In the reaction chamber 11, the cathode electrode 2 is disposed at the top. The cathode electrode 2 preferably has a shape in which at least a part of the surface shape coincides with the shape of the main surface of the translucent substrate 10 on which the first protective film 20 is to be formed. The cathode electrode 2 has a translucent base material 10, a cathode electrode having a shape that matches the shape of the main surface and the back surface of the main surface on which the first protective film 20 of the translucent base material 10 is to be formed. It can attach so that the surface of 2 may touch.

  FIG. 3 is a schematic cross-sectional view showing an example of the attached state. FIG. 3 is a cross-sectional view along the AA plane in FIG. The translucent substrate 10 is attached to the cathode electrode 2 in a state where the back surface Sb of the main surface Sa on which the first protective film 20 of the translucent substrate 10 is to be formed and the surface Sc of the cathode electrode 2 are in contact with each other. ing. The main surface Sa of the translucent substrate 10 and the surface Sc of the cathode electrode 2 have the same shape. In this example, since the thickness of the translucent substrate 10 is uniform, the back surface Sb of the translucent substrate 10 and the surface Sc of the cathode electrode 2 are in contact with each other. The surface portion of the cathode electrode 2 where the translucent substrate 10 is not attached is covered with a shield member 8 grounded in the reaction chamber 11 in order to prevent deposition of components of the protective film, and the shield member 8 and the cathode An insulating film 9 is sandwiched between the electrodes 2.

  The cathode electrode 2 can be supplied with high-frequency power (13.56 MHz) from a high-frequency power supply device 6 outside the reaction chamber 11. A bias capacitor 7 is disposed between the cathode electrode 2 and the high frequency power supply device 6. In addition, a heater 22 for adjusting the temperature in the reaction chamber 11 is provided in the reaction chamber 11.

In the reaction chamber 11, an organic titanium compound gas, an organic silicon compound gas, an oxygen (O ₂ ) gas, and an ethylene (C ₂ H ₄ ) gas, which are raw material gases for the first protective film 20 and the second protective film 30, In addition, Ar or He gas that is a carrier gas can be introduced. After passing through the flow rate controller 12, the oxygen gas is introduced into the reaction chamber 1 through the gas introduction pipe 3. Further, the ethylene gas is introduced into the reaction chamber 1 through the gas introduction pipe 17 after passing through the flow rate controller 12. Further, Ar and He gas function as a carrier gas for introducing an organotitanium compound and an organosilicon compound described later into the reaction chamber 11. Therefore, Ar or He gas may be replaced with other inert gas such as other rare gas or nitrogen gas.

  The container 15 is a container for containing an organotitanium compound or an organosilicon compound. In the present embodiment, the organic titanium compound and the organic silicon compound which are raw materials for forming the first protective film 20 and the second protective film 30 are used in a liquid or solid state. Therefore, the container 15 containing these raw materials is water-bathed or oil-bathed in the water tank 16 and the water temperature in the water tank 16 is adjusted by the temperature controller 20 to heat the organic titanium compound or the organic silicon compound to an appropriate temperature. The vapor pressure can be increased. Ar gas is introduced into the container 15 by the carrier gas introduction pipe 18 after passing through the flow rate controller 12. By bubbling an organotitanium compound or an organosilicon compound with Ar gas, a mixed gas thereof is obtained. This mixed gas passes through the pressure control valve 13 and the pressure controller 14 and is then introduced into the reaction chamber 11 by the raw material introduction pipe 4.

  Examples of the organic titanium compound used as the raw material of the first protective film 20 include metal titanium alkoxides such as titanium tetraethoxide, titanium tetraisopropoxide, and titanium tetrabutoxide; alkylamine organic titanium such as tetradimethylaminotitanium. Compound: Titanium halides such as titanium dichloride, titanium trichloride, and titanium tetrachloride are listed. Among these, metal titanium alkoxide is preferable and titanium tetraisopropoxide is more preferable from the viewpoints of high vapor pressure, material cost, and high oxidizing power (safety). These are used singly or in combination of two or more.

  Examples of the organosilicon compound that is a raw material for the second protective film 30 include alkylalkoxysilanes such as tetramethoxysilane, tetraethoxysilane, monomethyltriethoxysilane, and dimethyldiethoxysilane; dimethylsilane, tetramethylsilane, and hexamethyl. Alkyl silanes such as disilane; Halogenated silanes such as silane dichloride and silane trisilane; Silanes such as monosilane and disilane; and siloxane compounds such as hexamethylsiloxane. Among these, bifunctional or higher alkyl silanes and / or alkyl siloxanes are preferred from the viewpoint of high vapor pressure, material cost, and high oxidizing power (safety), and hexamethyldisilane and / or hexamethyldisilane. Siloxane is more preferred. These are used singly or in combination of two or more.

  Next, the manufacturing method of the translucent laminated body using this plasma CVD apparatus is demonstrated. Here, titanium tetraisopropoxide (hereinafter referred to as “TTIP”) is used as the organic titanium compound, and hexamethyldisilane or hexamethyldisiloxane (hereinafter referred to as “HMDS”) is used as the organic silane compound. However, the present invention is not limited to this case.

  First, the translucent substrate 10 is attached to a predetermined position of the cathode electrode 2. Next, the air in the reaction chamber 11 is evacuated by a vacuum pump to bring the reaction chamber 11 into a high vacuum. Thereafter, in the first protective film forming step, oxygen gas, ethylene gas, and a mixed gas of He and TTIP are introduced into the reaction chamber 11.

  Next, the temperature and pressure in the reaction chamber 11 are adjusted as necessary. The temperature and pressure in the reaction chamber 11 may be any temperature as long as the gas that is the raw material of the first protective film 20 can be converted into plasma, and may be, for example, about 20 to 120 ° C. and about 5 to 140 Pa.

Next, high frequency power is supplied to the cathode electrode 2. Thereby, glow discharge is generated in the reaction chamber 11 through the cathode electrode 2, and the gas in the reaction chamber 11 is turned into plasma. At this time, the gas in the reaction chamber 11 is turned into plasma and reacts with gas molecules of TTIP by the action of oxygen radicals to generate TiO ₂ . In plasma CVD using oxygen radicals, TTIP reacts with oxygen radicals, and the Ti—C bond and C—H bond are broken to produce precursors such as TiO _x and Ti (OH) _x . Then, these precursors are gradually deposited on the surface of the translucent substrate 10, whereby the first protection mainly comprising titanium oxide and containing carbon atoms is formed on the surface of the translucent substrate 10. A film 20 is formed.

  At this time, the content ratio R1 of carbon atoms is adjusted so as to satisfy the condition represented by the above formula (1a) by adjusting the mixing ratio of oxygen gas, TTIP gas, Ar gas, and ethylene gas. In addition, the content ratio R1 can be adjusted so as to satisfy the condition represented by the above formula (1a) by adjusting the process pressure and the high-frequency power (high-frequency output).

  Further, the residual stress of the first protective film 20 is adjusted to be within a desired numerical range by adjusting the high-frequency power at, for example, 100 W or less and simultaneously adjusting the carbon atom content R1 as described above. be able to. Furthermore, the thickness of the first protective film 20 is such that the amount of each gas introduced into the reaction chamber 11, the process pressure, the high frequency power (high frequency output), the temperature of the translucent substrate 10 and the plasma generation time ( By adjusting the (high frequency power supply time), it can be adjusted to fall within a desired numerical range.

  Next, at the same time as the supply of high-frequency power is stopped, the supply of the gas that is the raw material of the first protective film 20 into the reaction chamber 11 is stopped. Subsequently, after purging the inside of the reaction chamber 11, the residual gas in the reaction chamber 11 is evacuated by a vacuum pump to make the reaction chamber 11 high vacuum again. The temperature and pressure in the reaction chamber 11 at this time may be any gas as long as the gas that is the raw material of the second protective film 30 can be converted into plasma, and may be, for example, about 20 to 120 ° C. and about 5 to 140 Pa.

  Further, the container 15 stores HMDS as a raw material of the second protective film 30 instead of TTIP.

Next, in the second protective film forming step, oxygen gas, ethylene gas, and a mixed gas of He gas and HMDS are introduced into the reaction chamber 11 held at the above temperature and pressure, and high frequency power is applied to the cathode electrode. 2 is supplied. The mixed gas of He and HMDS is obtained by bubbling He into liquid HMDS. Then, glow discharge is generated in the reaction chamber 11 through the cathode electrode 2, and the gas in the reaction chamber 11 is turned into plasma. At this time, the gas in the reaction chamber 11 is turned into plasma and reacts with gas molecules of HMDS by the action of oxygen radicals to generate SiO ₂ . In plasma CVD using oxygen radicals, HMDS reacts with oxygen radicals, and the Si—C bond and C—H bond are cut to produce precursors such as SiO _x and Si (OH) _x . Then, by gradually depositing these precursors on the surface of the first protective film 20, the second protective film 30 mainly containing silicon oxide and containing carbon atoms is formed on the surface of the first protective film 20. Will be formed.

  At this time, the carbon atom content R2 is adjusted so as to satisfy the condition represented by the above formula (1a) by adjusting the mixing ratio of oxygen gas, HMDS gas, He gas, and ethylene gas. The content ratio R2 can be adjusted so as to satisfy the condition represented by the above formula (2a) by adjusting the process pressure and the high-frequency electric energy (high-frequency output).

  Further, the residual stress of the second protective film 30 is adjusted to be within a desired numerical range by adjusting the high-frequency power at, for example, 100 W or less and simultaneously adjusting the carbon atom content R2 as described above. be able to. Furthermore, the thickness of the second protective film 30 is such that the amount of each gas introduced into the reaction chamber 11, the process pressure, the high frequency power (high frequency output), the temperature of the translucent substrate 10 and the plasma generation time ( By adjusting the (high frequency power supply time), it can be adjusted to fall within a desired numerical range.

  Thus, the translucent laminate 1 in which the first protective film 20 and the second protective film 30 are laminated in this order on the main surface of the translucent substrate 10 is obtained. Since the first protective film 20 and the second protective film 30 are formed by plasma CVD in the sealed reaction chamber 11, it is possible to sufficiently prevent the organic solvent and the like from being discharged into the atmosphere. In addition, since the first protective film 20 and the second protective film 30 can be formed at a low temperature, the translucent substrate 10 is not deformed or deteriorated by heat during the formation of the first protective film 20 and the second protective film 30. It is hard to receive.

  By the way, around the cathode electrode 2, the velocity of electrons is very high compared with the velocity of ions. Therefore, only electrons flow into the cathode electrode 2 quickly, and the cathode electrode is negatively charged to have a slightly negative self-bias potential. On the other hand, ions that cannot reach the cathode electrode are concentrated all around the cathode electrode 2. A sheath (ion sheath) is formed uniformly. When the cathode electrode 2 becomes a negative bias potential, the bias capacitor 7 disposed between the cathode electrode 2 and the high frequency power supply device 6 holds the negative bias potential of the cathode electrode 2. In the ion sheath, TTIP and HMDS are dissociated, and ionized ions are present at high density. These ions are uniformly and slowly attracted toward the cathode 2 by a slight negative bias potential of the cathode electrode 2 and deposited on the surface of the translucent substrate 10 or the first protective film 20 to a substantially uniform thickness. By doing so, it is considered that the first protective film 20 and the second protective film 30 are formed.

  The translucent laminate 1 thus obtained is suitably used for a lens for a vehicle lamp such as an automobile. A vehicle lamp lens is required to have high impact resistance and weather resistance due to its use environment. Even if the translucent laminate 1 of the present embodiment is irradiated with sunlight for a long time, the translucent substrate 10 is sufficiently prevented from being colored. In addition, cracks and peeling of the first protective film 20 and the second protective film are suppressed even when subjected to an impact or exposed to a severe climate. Therefore, the translucent laminate 1 is suitable as a lens for a vehicle lamp that requires high translucency, particularly from the viewpoint of safety.

  Furthermore, since the second protective film 30 having excellent scratch resistance effectively functions as a hard coat for a vehicle lamp lens, the translucent laminate 1 provided with the second protective film 30 as an outermost layer is: From such a viewpoint, it is suitably used as a lens for a vehicle lamp.

  Further, when the translucent laminate 1 is used as a lens for a vehicle lamp, a thin film having a uniform film thickness can be produced even on a lens surface having a complicated shape. Therefore, an advantageous effect that chemical resistance performance such as gasoline, which is performance depending on the film thickness, can be improved is also recognized.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. The present invention can be variously modified without departing from the gist thereof.

  For example, the translucent base material of the present invention is not limited to a lens for a vehicle lamp, and the shape and use thereof are not limited as long as the base material can transmit visible light. Examples of the use of the translucent substrate other than the lens of the vehicle lamp include, for example, a vehicle window glass, a general window glass, a display element lens provided in a personal computer, a ship window glass, and an aircraft window glass. Can be mentioned. However, in order to accurately form a protective film having a uniform thickness by plasma CVD, the distance between the surface of the cathode electrode and the surface on which the protective film is to be formed should be approximately the same throughout. preferable. Therefore, it is preferable that the translucent substrate has a uniform thickness throughout.

  In addition to the above-mentioned polycarbonate and polymethyl methacrylate, the resin that is the material of the translucent base material is polyalkyl acrylate; polyacryl methacrylate other than polymethyl methacrylate; polypropylene; transparent polystyrene; transparent epoxy resin; Styrene monomer copolymer; polyarate; polysulfone; polyethersulfone; polyalkylene terephthalate such as polyethylene terephthalate and polybutylene terephthalate; polyimide and the like. Moreover, as a material of a translucent base material, a hard-coat process sample (double sample) is mentioned other than the said resin and glass.

  Further, the second protective film may not be provided, or a protective film mainly composed of another material may be provided instead of the second protective film. Further, another protective film may be provided on the surface of the second protective film.

  Moreover, as a use of the translucent laminate, in addition to the lens of the vehicle lamp described above, a window glass for a vehicle, a window glass for general use, a lens for a display element provided in a personal computer, a window glass for a ship, an aircraft A window glass is mentioned.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

Example 1
Using the same plasma CVD apparatus as described above, a translucent laminate was produced as follows. First, the cathode electrode was installed at a predetermined position of the plasma CVD apparatus. In addition, the surface area of the part which contact | connects the translucent base material of a cathode electrode was 400 cm < ² >. Next, a flat polycarbonate light-transmitting substrate (thickness: 3 mm) was attached so as to be in contact with a part of the surface of the cathode electrode.

  A yellow index (hereinafter referred to as “YI”) after irradiating this translucent substrate with light for a specific time is a spectrophotometer (trade name “CM-3700d” manufactured by Minolta, Inc.), light source: D65), the measurement was as shown in FIG. The horizontal axis in FIG. 5 indicates the spectral wavelength of the irradiation light. From FIG. 5, it was found that this translucent base material is likely to deteriorate particularly in the ultraviolet region.

  Next, the air present therein was evacuated with a vacuum pump until the pressure in the reaction chamber reached 0.1 Pa. Thereafter, oxygen gas, argon gas, TTIP gas, and helium gas were introduced into the reaction chamber. The flow rate of oxygen gas was 20 sccm, the flow rate of argon gas was 10 sccm, and the flow rate of helium gas was 5 sccm. The flow rate of TTIP gas was controlled to 40 Torr (about 5.3 kPa) by adjusting the mixed partial pressure with the carrier gas using the following calculation method. The liquid TTIP gas was obtained by bubbling a carrier gas over TTIP.

That is, assuming that the flow rate of TTIP is Fs, the vapor pressure is Ps, the flow rate of Ar or He gas as carrier gas is Fc, the pressure (partial pressure) is Pc, and the total pressure is Pa.
Pc / Ps = Fc / Fs
The relationship is established. here,
Pc = Pa-Ps
So,
Fs = Fc × Ps / (Pa−Ps)
It becomes. Therefore, after measuring the vapor pressure of TTIP, the flow rate of carrier gas, and the total pressure at each temperature, the flow rate of TTIP gas was controlled by adjusting them.

  Next, the pressure in the reaction chamber was maintained in the same manner as described above, and the heater was adjusted so that the temperature became 100 ° C. Then, high-frequency power was supplied to the cathode electrode with an RF output of 100 W, and the gas in the reaction chamber was turned into plasma to start the formation of the first protective film.

  And after forming the 1st protective film for 15 minutes, supply of high frequency electric power was stopped. Thus, a translucent laminate obtained by providing the first protective film on the surface of the translucent substrate was obtained.

  The film thickness of the 1st protective film in this translucent laminated body was measured with the surface roughness meter (The Nippon Vacuum Technology company make, brand name "DEKTAK6M"). Moreover, the content rate of the carbon atom in the 1st protective film, the titanium atom, and the oxygen atom was measured using the XPS apparatus (The product name "Quantera SXM" by ULVAC-PHI). These results are shown in Table 1.

  Further, the yellow index (hereinafter referred to as “YI”) of the translucent laminate was measured using an SM color computer (trade name “SM-3” manufactured by Suga Test Instruments Co., Ltd.). Furthermore, the haze of the translucent laminate was measured using a haze computer (trade name “Hz-2” manufactured by Suga Test Instruments Co., Ltd.). These results are shown in Table 1.

(Examples 2-6, Comparative Examples 1 and 2)
A translucent laminate was obtained in the same manner as in Example 1 except that the flow rates of oxygen gas, argon gas or ethylene gas, TTIP gas, and helium gas were changed as shown in Table 2. The carbon atom, titanium atom and oxygen atom content, YI, and haze in the first protective film of the obtained light-transmitting laminate were measured in the same manner as in Example 1. The results are shown in Table 1.

(Examples 7 to 12)
First, the laminated body formed by forming the 1st protective film on the surface of a translucent base material similarly to Example 1 was obtained. Next, the reaction chamber was purged, and the gas present therein was evacuated with a vacuum pump until the pressure therein became 0.1 Pa again. Thereafter, oxygen gas, ethylene gas, HMDS gas, and helium gas were introduced into the reaction chamber. Table 3 shows the flow rates of oxygen gas, ethylene gas, HMDS gas, and helium gas. The HMDS gas was obtained by bubbling helium gas into liquid HMDS.

  Next, the pressure in the reaction chamber was maintained in the same manner as described above, and the heater was adjusted so that the temperature became 100 ° C. Then, high-frequency power was supplied to the cathode electrode with an RF output of 100 W, and the gas in the reaction chamber was turned into plasma to start the formation of the second protective film.

  And after forming the 2nd protective film for 15 minutes, supply of high frequency electric power was stopped. Thus, a translucent laminate was obtained in which the first protective film and the second protective film were provided in this order on the surface of the translucent substrate.

  The film thickness of the 2nd protective film in this translucent laminated body was measured with the said surface roughness meter. Moreover, the content rate of the carbon atom in the 2nd protective film, the titanium atom, and the oxygen atom was measured using the above-mentioned XPS apparatus. These results are shown in Table 4.

  Moreover, YI of the translucent laminate was measured using the above-described SM color computer. Furthermore, the haze of the translucent laminate was measured using the haze computer. These results are shown in Table 4.

[Heat resistance evaluation]
Each translucent laminate described above was allowed to stand at 120 ° C. for 240 hours in an air atmosphere. Thereafter, the haze of the translucent laminate was measured to evaluate its heat resistance. The results are shown in Table 5. It is considered that the increase in haze is caused by the decrease in the diffuse transmittance due to the peeling of the protective film or the generation of cracks.

[Moisture and heat resistance evaluation]
The translucent laminates of Examples 3 and 10 were left to stand for 15 hours in an atmosphere of air at 120 ° C. and 95% RH, and PCT was performed. Thereafter, the haze of the translucent laminate was measured to evaluate its heat and moisture resistance. As a result, almost no change was observed in the haze before and after PCT in any translucent laminate, and it was confirmed that the heat-and-moisture resistance was good.

[Water resistance evaluation]
The translucent laminates of Examples 3 and 10 were immersed in ion exchange water at 40 ° C. for 240 hours. The haze of the subsequent translucent laminate was measured to evaluate its water resistance. As a result, almost no change was observed in the haze before and after immersion in water in any translucent laminate, and it was confirmed that the water resistance was good.

[Temperature resistance evaluation]
The translucent laminates of Examples 3 and 10 were immersed in ion exchange water at 80 ° C. for 240 hours. The haze of the subsequent translucent laminate was measured to evaluate its warm water resistance. As a result, almost no change was observed in the haze before and after immersion in water in any translucent laminate, and it was confirmed that the hot water resistance was good.

[Moisture resistance evaluation]
The translucent laminates of Examples 3 and 10 were allowed to stand for 240 hours in an air atmosphere, a high humidity environment of 60 ° C. and 95% RH. Thereafter, the haze of the translucent laminate was measured to evaluate its moisture resistance. As a result, all the translucent laminates were confirmed to have good moisture resistance with almost no change in haze before and after standing in a high humidity environment.

[Weather resistance evaluation]
The light-transmitting laminates of Examples 3 and 10 were subjected to an accelerated weather resistance test using a 2000 hour SWOM (Sunshine Weatherometer). The haze of the subsequent translucent laminate was measured to evaluate its weather resistance. As a result, in any translucent laminate, almost no change was found in the haze before and after this test, and it was confirmed that the weather resistance was good.

(Comparative Example 3)
A translucent laminate of Comparative Example 3 was obtained in the same manner as in Example 10 except that the first protective film was not provided and the second protective film was formed directly on the surface of the translucent substrate.

[Evaluation of UV blocking properties]
An accelerated weather resistance test by SWOM for a predetermined time was performed on the translucent laminates of Examples 3 and 10 and Comparative Example 3, and the translucent base material provided with no protective film. And YI of each translucent laminated body and translucent base material after an accelerated weather resistance test was measured. The results are shown in FIG. b1 is Example 3, b2 is Example 10, b3 is YI when the translucent laminate of Comparative Example 3 is used, and b4 is YI when a translucent substrate is used. The horizontal axis indicates the time of accelerated weathering test.

(Examples 13 and 14)
The translucent laminates of Examples 13 and 14 were respectively formed in the same manner as in Example 1 except that the formation time of the first protective film was changed and the film thickness was changed to 0.3 μm and 1.0 μm. Obtained.

[Measurement of light transmittance]
Using a spectrophotometer (trade name “U-4100”, manufactured by Hitachi, Ltd., light source: D2 and WI), the light transmittance of the translucent laminates of Examples 3, 13, and 14 was measured. The results are shown in FIG. 4, a1 is Example 13 (first protective film thickness: 0.3 μm), a2 is Example 3 (first protective film thickness: 0.5 μm), and a3 is Example 14 (first protective film). It is a result concerning a translucent laminate having a film thickness of 1.0 μm. From these results, it was confirmed that when the film thickness of the first protective film was 0.3 μm or more, excellent ultraviolet blocking properties were exhibited.

(Examples 15 and 16)
Except for changing the formation time of the first protective film and the second protective film and changing the film thickness of the first protective film to 0.5 μm and the film thickness of the second protective film to 1.0 μm and 0.3 μm, respectively. In the same manner as Example 7, translucent laminates of Examples 15 and 16 were obtained.

(Comparative Examples 4-6)
Transparency of Comparative Examples 4 to 6 was the same as Comparative Example 3 except that the formation time of the second protective film was changed and the film thickness was changed to 0.5 μm, 1.0 μm, and 2.0 μm, respectively. A conductive laminate was obtained.

[Abrasion resistance evaluation]
Using a commercially available rubbing tester as a sample, the translucent laminates of Examples 15 and 16, and Comparative Examples 4 to 6, the translucent base material, and the hard coat for automobile lamps by the applicant as a reference example, Abrasion evaluation was performed. The evaluation was performed before and after scratching the surface of the sample under the conditions of load: 510 g, rubbing distance: 60 mm one way, rubbing speed: 11 reciprocations / minute, number of rubbing: 50 reciprocations, abrasive: steel wool No.000. Was measured by the above-mentioned haze computer, and the amount of change in haze before and after the scratch (Δhaze) was derived. The results are shown in Table 6.

It is a schematic cross section of the translucent laminated body which concerns on this invention. 1 is a schematic diagram of a plasma CVD apparatus according to an embodiment of the present invention. It is a schematic cross section along the AA line of FIG. It is a spectral transmittance curve of the translucent laminated body which concerns on an Example. It is a figure which shows the YI curve by the spectral irradiation of a translucent base material. It is a figure which evaluates the weather resistance of a translucent laminated body and a translucent base material.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Translucent laminated body, 2 ... Cathode electrode 3, 17, 18 ... Gas introduction pipe, 4 ... Raw material introduction pipe, 5 ... Vacuum exhaust pipe, 6 ... High frequency power supply device, 7 ... Bias capacitor, 8 ... Shield member , 9 ... Insulating film, 10 ... Translucent substrate, 11 ... Reaction chamber, 12 ... Flow rate controller, 13, 14 ... Pressure controller, 15 ... Container, 16 ... Water tank, 20 ... First protective film, 22 ... Heater, 24 ... temperature control device, 30 ... second protective film.

Claims (3)

A translucent substrate;
A first protective film formed on the main surface of the translucent substrate by a plasma CVD method and mainly composed of titanium oxide;
A second protective film formed on the main surface of the first protective film opposite to the light-transmitting substrate by a plasma CVD method and mainly composed of silicon oxide;
With
The first protective film satisfies the condition represented by the following formula (1), and the second protective film satisfies the condition represented by the following formula (2).
6% ≦ A _C / (A _Ti + A _O + A _C ) × 100 ≦ 15% (1)
(In the formula (1), A _C is contained in the oxygen atom in the content by mass of carbon atoms in the first protective film, A _Ti is contained mass of the titanium atoms in the first protective film, A _O is the first protective film (Indicates mass.)
6% ≦ B _C / (B _Si + B _O + B _C ) × 100 ≦ 20% (2)
(In the formula (2), B _C is contained in the oxygen atom in the content by mass of carbon atoms in the second protective layer, B _Si is contained mass of silicon atoms in the second protective layer, B _O is the second protective layer (Indicates mass.) The translucent laminate according to claim 1 , wherein the second protective film has a residual stress of 6000 MPa or less. The first protective layer has a thickness of 0.3 to 1.0 [mu] m, the second protective film has a thickness of 0.75～2.0Myuemu, translucent according to claim 1 or 2 Laminated body.

Images