Stacked body and method for manufacturing stacked body

Abstract

The layered body (1) has a first inorganic hard coat layer (12) formed on a resin substrate (10) by a plasma CVD method, and a second inorganic hard coat layer (14) formed on the first inorganic hard coat layer (12) by a plasma CVD method, the refractive index of the first inorganic hard coat layer (12) being greater than that of the second inorganic hard coat layer (14).

Description

Technical Field

[0001] Embodiments of the present invention relate to laminates and methods for manufacturing laminates. Background Technology

[0002] To improve the hardness and scratch resistance of resin substrates, a laminate in which a hard coating is formed on the resin substrate has been disclosed. For example, a structure in which an intermediate layer of acrylic or the like is formed on the resin substrate by a wet process, and a hard coating is formed on the intermediate layer has been disclosed.

[0003] However, when the process includes forming an intermediate layer using a wet process, the extended manufacturing time becomes a problem. Therefore, a structure for forming a hard coating on a resin substrate using a dry process is disclosed.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2016-022612 Summary of the Invention

[0005] The problem that the invention aims to solve

[0006] However, in the prior art, sometimes when a hard coating is formed on a resin substrate using a dry process, cracks appear in the hard coating, resulting in low hardness. In other words, in the prior art, there are cases where the hardness of the laminate between the resin substrate and the hard coating is low.

[0007] The present invention was made in view of the above circumstances, and its object is to provide a laminate capable of improving the hardness of a hard coating and a method for manufacturing the laminate.

[0008] means for solving problems

[0009] The laminate of the embodiment includes a first inorganic hard coating formed on a resin substrate by plasma CVD and a second inorganic hard coating formed on the first inorganic hard coating by plasma CVD, wherein the refractive index of the first inorganic hard coating is greater than the refractive index of the second inorganic hard coating. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of an example of a stacked body in an embodiment.

[0011] Figure 2A This is a schematic diagram illustrating an example of a method for manufacturing a laminated body according to an embodiment.

[0012] Figure 2B This is a schematic diagram illustrating an example of a method for manufacturing a laminated body according to an embodiment.

[0013] Figure 2CThis is a schematic diagram illustrating an example of a method for manufacturing a laminated body according to an embodiment.

[0014] Figure 2D This is a schematic diagram illustrating an example of a method for manufacturing a laminated body according to an embodiment.

[0015] Figure 2E This is a schematic diagram illustrating an example of a method for manufacturing a laminated body according to an embodiment.

[0016] Figure 3A This is an illustration of the effects of surface modification.

[0017] Figure 3B This is an illustration of the effects of surface modification.

[0018] Figure 3C This is an illustration of the effects of surface modification. Detailed Implementation

[0019] Hereinafter, the laminated body and its manufacturing method according to this embodiment will be described in detail with reference to the accompanying drawings. It should be noted that in the drawings, the same reference numerals are sometimes used to label the same components, and repeated descriptions are omitted.

[0020] Figure 1 This is a schematic diagram of an example of the laminate 1 in this embodiment.

[0021] The laminate 1 is a laminate on a resin substrate 10 in which a first inorganic hard coating 12, a second inorganic hard coating 14 and a third inorganic hard coating 16 are sequentially laminated.

[0022] The laminate 1 can be a laminate with at least a first inorganic hard coating 12 and a second inorganic hard coating 14 stacked on the resin substrate 10, or it can be a structure without a third inorganic hard coating 16.

[0023] The resin substrate 10 is a substrate made of resin. For example, the resin substrate 10 used in automobile headlight covers and the like is made of a plastic material that is transparent to visible light.

[0024] Examples of plastic materials used in the resin substrate 10 include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), and polymethyl methacrylate (PMMA).

[0025] The shape of the resin substrate 10 can be a thin film, sheet, or plate, depending on its application. When the resin substrate 10 is plate-shaped, it can also be an injection-molded article. In this embodiment, an example of a plate-shaped resin substrate 10 will be described.

[0026] The first inorganic hard coating 12, the second inorganic hard coating 14 and the third inorganic hard coating 16 are hard coatings made of inorganic materials formed by plasma CVD (Chemical Vapor Deposition).

[0027] The refractive index of the first inorganic hard coating 12 is greater than that of the second inorganic hard coating 14. The refractive index of the second inorganic hard coating 14 is greater than that of the third inorganic hard coating 16.

[0028] That is, the relationship between the refractive indices of the first inorganic hard coating 12, the second inorganic hard coating 14 and the third inorganic hard coating 16 is expressed by the following formula (1).

[0029] Relationship of refractive index: Third inorganic hard coating 16 < Second inorganic hard coating 14 < First inorganic hard coating 12 ... Equation (1)

[0030] The refractive indices of the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 can be adjusted according to the purpose of the laminate 1, as long as they are within the range that satisfies the above relationship.

[0031] Specifically, the refractive index of the first inorganic hard coating 12 is preferably in the range of 1.437 or higher and 1.450 or lower, and more preferably in the range of 1.437 or higher and 1.440 or lower. Furthermore, the refractive index of the second inorganic hard coating 14 is preferably in the range of 1.410 or higher and 1.433 or lower, and more preferably in the range of 1.420 or higher and 1.433 or lower. Additionally, the refractive index of the third inorganic hard coating 16 is preferably in the range of 1.348 or higher and 1.378 or lower, and more preferably in the range of 1.358 or higher and 1.368 or lower.

[0032] The refractive indices of the resin substrate 10, the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 were determined by measuring the reflectance using a Hitachi High-Tech spectrophotometer at an incident angle of 15 degrees and fitting the results using an optical simulation application.

[0033] The first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 can be composed of the same or different constituent components. When composed of the same constituent components, the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 may differ only in the proportion of at least a portion of their constituent components. For example, when composed of the same constituent components, the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 are preferably composed of SiOx.

[0034] When the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 are composed of SiOx, the values ​​of x are different. Specifically, the x value x1 of the first inorganic hard coating 12 composed of SiOx is less than the x value x2 of the second inorganic hard coating 14 composed of SiOx. Furthermore, the x value x3 of the third inorganic hard coating 16 composed of SiOx is greater than the x value x2 of the second inorganic hard coating 14 composed of SiOx. As x approaches 2, the properties of the silicone resin become closer to those of silicon dioxide, and the hardness increases. Therefore, by satisfying the above relationships, the surface layer can be made to be closer to a glass-like state, and the underlying layer can be made to be a soft silicone resin-like material, thus becoming an impact-absorbing layer.

[0035] That is, the relationship between the values ​​of x of the first inorganic hard coating 12, the second inorganic hard coating 14 and the third inorganic hard coating 16 composed of SiOx is expressed by the following formula (2).

[0036] The relationship between the values ​​of x in SiOx: First inorganic hard coating 12 < Second inorganic hard coating 14 < Third inorganic hard coating 16... Equation (2)

[0037] The x values ​​of the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16, which are composed of SiOx, can be adjusted according to the purpose of the laminate 1, etc., within the range that satisfies the above relationship.

[0038] Specifically, the x value of the first inorganic hard coating 12 composed of SiOx is preferably in the range of 1.05 or higher and 1.15 or lower. Furthermore, the x value of the second inorganic hard coating 14 composed of SiOx is preferably in the range of 1.2 or higher and 1.4 or lower. Additionally, the x value of the third inorganic hard coating 16 composed of SiOx is preferably in the range of 1.45 or higher and 1.65 or lower.

[0039] The x values ​​of the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16, which are composed of SiOx, were determined by an EDX analyzer under EDX analysis conditions of 10K times.

[0040] It should be noted that the SiOx constituting the first inorganic hard coating 12, the second inorganic hard coating 14 and the third inorganic hard coating 16 may contain carbon (C).

[0041] The thickness of the second inorganic hard coating 14 is preferably greater than the thickness of the first inorganic hard coating 12 and the third inorganic hard coating 16.

[0042] That is, the relationship between the thicknesses of the first inorganic hard coating 12, the second inorganic hard coating 14 and the third inorganic hard coating 16 is preferably represented by the following formula (3). This is because the first inorganic hard coating 12 is close to the state of organosilicon resin, and therefore has a small amount of water solubility. When the third inorganic hard coating 16 becomes thicker, cracks are more likely to occur.

[0043] Relationship to thickness: First inorganic hard coating 12 and third inorganic hard coating 16 < second inorganic hard coating 14... Equation (3)

[0044] The thicknesses of the resin substrate 10, the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 can be adjusted according to the purpose of the laminate 1, as long as they are within the range that satisfies the above relationship.

[0045] Specifically, for example, the thickness of the resin substrate 10 is preferably in the range of 1.5 mm or more and 5.0 mm or less, more preferably in the range of 1.5 mm or more and 4.0 mm or less. The thickness of the first inorganic hard coating 12 is preferably in the range of 100 nm or more and 500 nm or less, more preferably in the range of 200 nm or more and 400 nm or less. The thickness of the second inorganic hard coating 14 is preferably in the range of 700 nm or more and 1000 nm or less, more preferably in the range of 900 nm or more and 1000 nm or less. The thickness of the third inorganic hard coating 16 is preferably in the range of 300 nm or more and 600 nm or less, more preferably in the range of 400 nm or more and 500 nm or less.

[0046] Next, the manufacturing method of the laminate 1 of this embodiment will be described.

[0047] Figures 2A-2E This is a schematic diagram illustrating an example of a method for manufacturing the laminate 1 according to this embodiment.

[0048] The manufacturing method of the laminate 1 includes a surface modification step, a first inorganic hard coating forming step, a second inorganic hard coating forming step, a third inorganic hard coating forming step, and a heating step. It should be noted that the manufacturing method of the laminate 1 without the third inorganic hard coating 16 does not include the third inorganic hard coating forming step.

[0049] Figure 2A This is an explanatory diagram of the surface modification process. The surface modification process is a process of modifying the surface of the resin substrate 10.

[0050] In this embodiment, "surface modification" refers to the process of cleaving the molecular chains present on the surface of the resin substrate 10 to generate functional groups such as hydroxyl, carboxyl, and formyl groups. Examples of surface modification include monochromatic light irradiation, plasma treatment, ultraviolet irradiation, UV (Ultra Violet) ozone treatment, microbubble ozone water treatment, or electrolytic sulfuric acid treatment. Electrolytic sulfuric acid is a solution generated by electrolyzing sulfuric acid. The modification treatment may employ only one of these methods, or it may involve performing two or more methods sequentially.

[0051] Among these various surface treatments, when using a substrate made of polycarbonate as the resin substrate 10, monochromatic light irradiation treatment is preferred.

[0052] In detail, during the surface modification process, monochromatic light with a wavelength of 380 nm or higher and 420 nm or lower is irradiated onto the resin substrate 10 made of polycarbonate. Specifically, an LED (Light Emitting Diode) that emits monochromatic light of this wavelength is used to irradiate the resin substrate 10 with light based on the LED, thereby modifying the surface of the resin substrate 10. Through the surface modification of the resin substrate 10, the adhesion to the first inorganic hard coating 12 formed on the resin substrate 10 can be improved.

[0053] Figure 2B This is an explanatory diagram of the first inorganic hard coating formation process. A first inorganic hard coating 12, for example composed of SiOx, is formed on a resin substrate 10 by plasma CVD.

[0054] Figure 2C This is an explanatory diagram of the second inorganic hard coating formation process. A second inorganic hard coating 14, for example composed of SiOx, is formed on the first inorganic hard coating 12 by plasma CVD.

[0055] Figure 2D This is an explanatory diagram of the third inorganic hard coating formation process. A third inorganic hard coating 16, for example composed of SiOx, is formed on the second inorganic hard coating 14 by plasma CVD.

[0056] In the plasma CVD method used in each of the first, second, and third inorganic hard coating formation processes, plasma CVD method using a plasma generation device can be used.

[0057] As a plasma generating device, low-temperature plasma generating devices such as DC plasma, low-frequency plasma, high-frequency plasma, pulsed wave plasma, three-pole structure plasma, and microwave plasma are used.

[0058] The inorganic hard coatings composed of SiOx (first inorganic hard coating 12, second inorganic hard coating 14, and third inorganic hard coating 16) can be formed using organosilane compounds and oxygen as raw materials. As organosilane compounds, low molecular weight organosilane compounds such as tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), tetramethylsilane (TMS), hexamethyldisiloxane (HMDSO), tetramethyldisiloxane, and methyltrimethoxysilane can be used.

[0059] In the plasma CVD method for film formation, the aforementioned organosilanes are vaporized and mixed with oxygen to form a substance between electrodes. A low-temperature plasma generator is used to apply electricity to perform plasma formation, thereby forming a hard coating of SiO containing carbon (C) on the already formed lower layer.

[0060] In plasma CVD, the film quality can be altered through various methods, such as by changing the organosilane compound, the type of gas, the mixing ratio of the organosilane compound to oxygen, and adjusting the applied power. Therefore, by controlling the mixing ratio of the organosilane compound to oxygen, the oxygen composition (value of x) of the carbon-containing SiOx can be adjusted. By adjusting the value of x in SiOx, the densities of the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 can be adjusted to the relationship described above.

[0061] For example, in the plasma CVD process for forming the second inorganic hard coating 14, the mixture of organosilane compound and oxygen is mixed at a ratio of 6 to 110 moles of oxygen relative to the flow rate of 1 mole of organosilane compound. By setting the mixture of organosilane compound and oxygen in the above-mentioned range, the x value of SiOx in the second inorganic hard coating 14 can be adjusted to a range of 1.2 to 1.4.

[0062] Furthermore, for example, when forming the first inorganic hard coating 12 by plasma CVD, the mixed gas of organosilane compound and oxygen is mixed at a ratio of 4 to 6 moles of oxygen relative to 1 mole of organosilane compound flow rate. By setting the mixed gas of organosilane compound and oxygen during the formation of the first inorganic hard coating 12 to the above-mentioned mixing ratio, the x value of SiOx in the first inorganic hard coating 12 can be adjusted to a range of 1.05 to 1.15.

[0063] Furthermore, for example, when forming the third inorganic hard coating 16 by plasma CVD, the mixed gas of organosilane compound and oxygen is mixed at a ratio of 10 to 20 moles of oxygen flow rate relative to 1 mole of organosilane compound flow rate. By setting the mixed gas of organosilane compound and oxygen during the formation of the third inorganic hard coating 16 to the above-mentioned mixing ratio, the x value of SiOx in the third inorganic hard coating 16 can be adjusted to a range of 1.45 to 1.65.

[0064] The thicknesses of the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 can be adjusted by adjusting the formation time using plasma CVD.

[0065] It should be noted that in the plasma CVD deposition of at least one of the inorganic hard coatings (first inorganic hard coating 12, second inorganic hard coating 14, and third inorganic hard coating 16), the ratio of the organosilane compound to oxygen in the mixed gas can be continuously varied. In this case, it is not... Figure 1 The layered structure shown can form a stacked structure in which the value of x of SiOx varies continuously.

[0066] Figure 2E This is an explanatory diagram of the heating process. In the heating process, the laminate on the resin substrate 10, on which the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 are stacked, is heated to a temperature above the temperature at which carbon contained in the inorganic hard coating at the position furthest from the resin substrate 10, i.e., on the surface of the laminate disposed on the opposite side of the resin substrate 10, is removed, and below the glass transition temperature of the resin substrate 10.

[0067] For example, it is conceivable that the laminate 1 is a laminate on a resin substrate 10 having a first inorganic hard coating 12 and a second inorganic hard coating 14. In this case, during the heating process, heating is performed at a temperature above the temperature at which carbon contained in the second inorganic hard coating 14 formed by plasma CVD can be removed and below the glass transition temperature of the resin substrate 10.

[0068] Alternatively, for example, the laminate 1 may be conceived as a laminate on a resin substrate 10 having a first inorganic hard coating 12, a second inorganic hard coating 14, and a third inorganic hard coating 16. In this case, during the heating process, heating is performed at a temperature above the temperature capable of removing carbon contained in the third inorganic hard coating 16 formed by plasma CVD and below the glass transition temperature of the resin substrate 10. A heating temperature satisfying the above conditions is, for example, 100°C, but is not limited to this temperature.

[0069] There is no limit to the heating time in the heating process. The heating time may be, for example, 3 hours to 12 hours, but is not limited to this range.

[0070] Through sequential use Figures 2A-2E The laminate 1 is formed by the surface modification process, the first inorganic hard coating formation process, the second inorganic hard coating formation process, the third inorganic hard coating formation process, and the heating process.

[0071] As described above, the laminate 1 of this embodiment includes a first inorganic hard coating 12 formed on a resin substrate 10 by plasma CVD, and a second inorganic hard coating 14 formed on the first inorganic hard coating 12 by plasma CVD, wherein the refractive index of the first inorganic hard coating 12 is greater than the refractive index of the second inorganic hard coating 14.

[0072] Thus, in the laminate 1 of this embodiment, the refractive indices of the first inorganic hard coating 12 and the second inorganic hard coating 14, which are disposed between the resin substrate 10 and the second inorganic hard coating 14, are greater than the refractive index of the third inorganic hard coating 14. This indicates that the first inorganic hard coating 12 and the second inorganic hard coating 14 are close to the state of silicone resin. The silicone resin state differs from the glass state and has viscoelasticity. Therefore, for stresses generated during the manufacture of the laminate 1 using dry methods such as plasma CVD, the stresses on the resin substrate 10 and the second inorganic hard coating 14 can be absorbed by the first inorganic hard coating 12 and the second inorganic hard coating 14 due to heat, absorbing the difference in expansion between the film and the substrate caused by heat. Therefore, it is possible to suppress the low hardness caused by cracks in the second inorganic hard coating 14, and to achieve an increase in the hardness of the hard coating including the first inorganic hard coating 12 and the second inorganic hard coating 14.

[0073] Therefore, the laminate 1 of this embodiment can achieve an increase in the hardness of the hard coating.

[0074] In addition, the manufacturing method of the laminate 1 in this embodiment includes a surface modification step of irradiating a resin substrate 10, which serves as a polycarbonate substrate, with monochromatic light of wavelengths above 380 nm and below 420 nm.

[0075] By irradiating the resin substrate 10 with monochromatic light of the aforementioned wavelength, surface modification can be performed, thereby suppressing discoloration of the resin substrate 10 and achieving surface modification. Furthermore, by performing surface modification on the resin substrate 10, the adhesion to the first inorganic hard coating 12 formed on the resin substrate 10 can be improved.

[0076] Figures 3A-3C This is an illustration of the effects of surface modification.

[0077] Figure 3AThis is a graph showing the measurement results of the absorption peaks of the resin substrate 10, which serves as a polycarbonate substrate, before surface modification.

[0078] Figure 3B This is a graph showing the measurement results of the absorption peak of the resin substrate 10 after surface modification when the surface of the resin substrate 10, which is a polycarbonate substrate, is irradiated with white light, which is a polychromatic light. A metal hydride lamp is used for white light irradiation.

[0079] Figure 3C This is a graph showing the measurement results of the absorption peak of the resin substrate 10 after surface modification when the surface of the resin substrate 10, which is a polycarbonate substrate, is modified by irradiating it with blue light (wavelength 395nm) as monochromatic light by an LED.

[0080] like Figure 3B As shown, the absorption peak of the resin substrate 10 after surface modification by irradiation with white light is compared with the absorption peak before surface modification (refer to...). Figure 3A A new peak was observed at a wavelength of 388 nm. The inventors discovered that this peak at 388 nm is related to yellowing. Therefore, when the surface of the resin substrate 10 is modified by irradiation with white light, it can be confirmed that the transparent resin substrate 10 changes color.

[0081] On the other hand, such as Figure 3C As shown, in the absorption peaks of the resin substrate 10 after surface modification by irradiation with blue light, no peak is observed at a wavelength of 388 nm, which is related to color change, but a peak is observed at a wavelength of 469 nm. The inventors discovered that this peak at wavelength 469 nm is related to adhesion. Therefore, it was confirmed that when the surface of the resin substrate 10 is modified by irradiation with blue light, the color change of the transparent resin substrate 10 is suppressed, and the adhesion to the first inorganic hard coating 12 is improved.

[0082] return Figure 2E Continuing the explanation, it is also conceivable that the laminate 1 is a laminate in which a first inorganic hard coating 12 and a second inorganic hard coating 14 are laminated on a resin substrate 10. In this case, during the heating process, the temperature is set above the temperature at which carbon contained in the second inorganic hard coating 14 formed by plasma CVD can be removed, but below the glass transition temperature of the resin substrate 10. It is also conceivable that the laminate 1 is a laminate in which a first inorganic hard coating 12 and a second inorganic hard coating 14 are laminated on a resin substrate 10. In this case, during the heating process, the temperature is set above the temperature at which carbon contained in the second inorganic hard coating 14 formed by plasma CVD can be removed, but below the glass transition temperature of the resin substrate 10.

[0083] Therefore, the carbon contained in the inorganic hard coating (second inorganic hard coating 14 or third inorganic hard coating 16) on the outermost surface of the laminate 1 opposite to the resin substrate 10 is removed by the heating process, which can improve the stoichiometric composition of SiOx and further improve the hardness.

[0084] In addition, as described above, the laminate 1 can be any laminate having at least a first inorganic hard coating 12 and a second inorganic hard coating 14 laminated on the resin substrate 10, but it is preferable to also have a third inorganic hard coating 16.

[0085] By configuring the structure to include the third inorganic hard coating 16, the barrier properties of the second inorganic hard coating 14 can be improved, thereby enhancing weather resistance.

[0086] Furthermore, the relationship between the thicknesses of the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 constituting the laminate 1 is preferably expressed by the above formula (3).

[0087] By ensuring that the thickness relationship satisfies the relationship expressed by the above formula (3), and by setting it to the above density, the thickness of the second inorganic hard coating 14 among the hard coatings containing the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 is maximized, thereby giving the film elasticity and mitigating impacts such as scratches. That is, by maximizing the thickness of the hardest second inorganic hard coating 14, and ensuring that the thicknesses of the first inorganic hard coating 12 and the third inorganic hard coating 16 other than the second inorganic hard coating 14 are less than the thickness of the second inorganic hard coating 14, it is possible to prevent the hard coating of the laminate 1 from becoming too soft as a whole, and to suppress cracking of the hard coating.

[0088] It should be noted that the laminate 1 may also be composed of one or more layers further provided on the third inorganic hard coating 16. At least one of the one or more layers formed on the third inorganic hard coating 16 may be composed of the same constituent material (e.g., SiOx) as the first inorganic hard coating 12, the second inorganic hard coating 14 and the third inorganic hard coating 16, or may be composed of different constituent materials.

[0089] The one or more layers formed on the third inorganic hard coating 16 may have a higher layer density as they are disposed further away from the resin substrate 10, or they may have a density corresponding to the purpose of the laminate 1. In addition, when at least a portion of the one or more layers formed on the third inorganic hard coating 16 is composed of SiOx, the value of x may be a value that is larger as the layers are disposed further away from the resin substrate 10, or it may be a value corresponding to the purpose of the laminate 1.

[0090] In addition, one or more layers formed on the third inorganic hard coating 16 may also include a protective layer made of fluororesin or the like.

[0091] Example

[0092] The present invention will now be specifically described through embodiments. However, the present invention is not limited to the following embodiments.

[0093] (Example 1)

[0094] A polycarbonate substrate (manufactured by Mitsubishi Engineering Plastics Co., Ltd., grade NF2000VUNS2) was prepared as the resin substrate 10. The dimensions of the resin substrate 10 as the polycarbonate substrate are 50 mm in length × 50 mm in width × 3 mm in thickness. In addition, the refractive index of the polycarbonate substrate is 1.618. The method for measuring the refractive index will be described later.

[0095] The surface of the resin substrate 10 is modified by irradiating the surface of the resin substrate 10 with monochromatic blue light with a wavelength of 360nm~405nm for 30 seconds using a blue LED.

[0096] A first inorganic hard coating 12 is formed on the surface-modified resin substrate 10 by plasma CVD.

[0097] Specifically, a high-frequency plasma CVD device is used to exhaust the vacuum in the chamber to 9.0 × 10⁻⁶. -3 After the pressure drops below Pa, the mixed gas used as feedstock is prepared by setting the flow rate of hexamethyldisiloxane (HMDSO) to 300 sccm and the flow rate of oxygen (O2) to 1800 sccm, with the volume ratio of HMDSO to oxygen (O2) controlled at HMDSO:O2 = 1:6, and then introducing it into the chamber. Then, the plasma excitation power is set to 3 W / cm². 2 High-frequency plasma CVD was performed to form a first inorganic hard coating 12 containing carbon SiOx.

[0098] The thickness of the first inorganic hard coating 12 is 200 nm. Furthermore, the refractive index of the first inorganic hard coating 12 is 1.435, and the x-value of the SiO constituting the first inorganic hard coating 12 is 1.1. The methods for determining the refractive index and x-values ​​will be described later.

[0099] Next, a second inorganic hard coating 14 is formed on the first inorganic hard coating 12.

[0100] When forming the second inorganic hard coating 14, the RF poewr is set to 1800W as a condition based on plasma CVD. Otherwise, the second inorganic hard coating 14 is formed under the same conditions as the first inorganic hard coating 12.

[0101] The thickness of the formed second inorganic hard coating 14 is 900 nm. Furthermore, the refractive index of the second inorganic hard coating 14 is 1.433, and the x-value of the SiO constituting the second inorganic hard coating 14 is 1.3. The methods for determining the refractive index and x-values ​​are described later.

[0102] Next, the laminate of resin substrate 10, first inorganic hard coating 12 and second inorganic hard coating 14 is heated at 100°C for 3 hours in the atmosphere to produce laminate 1 of Example 1.

[0103] (Example 2)

[0104] On the same resin substrate 10 as in Example 1, which is a polycarbonate substrate, surface modification is performed in the same manner as in Example 1, and the first inorganic hard coating 12 and the second inorganic hard coating 14 are formed sequentially by plasma CVD in the same manner as in Example 1.

[0105] The third inorganic hard coating 16 is formed on the second inorganic hard coating 14 by plasma CVD.

[0106] When forming the third inorganic hard coating 16, the HMDSO flow rate was set to 150 sccm as a condition for using plasma CVD. Otherwise, the third inorganic hard coating 16 was formed under the same conditions as the first inorganic hard coating 12 in Example 1.

[0107] The thickness of the formed third inorganic hard coating 16 is 300 nm. Furthermore, the refractive index of the third inorganic hard coating 16 is 1.358, and the x-value of the SiO constituting the third inorganic hard coating 16 is 1.5. The methods for determining the refractive index and x-values ​​are described later.

[0108] Next, the laminate of resin substrate 10, first inorganic hard coating 12, second inorganic hard coating 14 and third inorganic hard coating 16 is heated at 100°C for 3 hours in the atmosphere to produce laminate 1 of Example 2.

[0109] (Comparative Example 1)

[0110] On a resin substrate 10, which is the same as the polycarbonate substrate in Example 1, surface modification was performed in the same manner as in Example 1 to produce a comparative laminate of Comparative Example 1.

[0111] (Determination of the value of x in SiOx)

[0112] The x values ​​of SiOx constituting the first inorganic hard coating 12, the second inorganic hard coating 14 and the third inorganic hard coating 16 were determined under the following conditions.

[0113] In determining the value of x, for the layer of the object being measured, EDX analysis is used, and the value obtained from the atomic concentration based on the 10K-fold condition is taken as the value of x.

[0114] (Determination of refractive index)

[0115] The refractive indices of the resin substrate 10, the first inorganic hard coating 12, the second inorganic hard coating 14, and the third inorganic hard coating 16 were determined under the following conditions.

[0116] Regarding the determination of refractive index, for the layer of the object being measured, a Hitachi High-Tech spectrophotometer was used to measure the reflectance under the condition of an incident angle of 15 degrees. The value obtained by fitting the measurement result with an optical simulation application was then used as the refractive index.

[0117] evaluate

[0118] The pencil hardness and cracking were evaluated for the laminates 1 of Examples 1-2 and the comparative laminate of Comparative Example 1, which were prepared through the above-described process.

[0119] (Evaluation of pencil hardness)

[0120] For each laminate 1 of Examples 1-2 and the comparative laminate of Comparative Example 1, the hardness was measured using a JIS standard pencil hardness tester (manufactured by Taiyu Machinery Co., Ltd.) under the conditions of JIS K 5600-5-4, and the model of the hardest pencil without damage was used as the evaluation value.

[0121] It should be noted that, for the laminate 1 of Example 1, the surface of the second inorganic hard coating 14, for the laminate 1 of Example 2, the surface of the third inorganic hard coating 16, and for the comparative laminate of Comparative Example 1, the surface of the resin substrate 10, the pencil hardness was evaluated.

[0122] The pencil hardness was evaluated sequentially from softest to H, 2H, 3H, and 4H. The hardness of the softest side (1st hardness), where scratches begin to appear, was taken as the maximum hardness that would not cause scratches. The evaluation results are shown in Table 1.

[0123] (Evaluation of the crack)

[0124] The crack formation on the surfaces of each laminate 1 of Examples 1-2 and the comparative laminate of Comparative Example 1 was evaluated. For the laminate 1 of Example 1, the crack formation on the surface side of the second inorganic hard coating 14 was evaluated; for the laminate 1 of Example 2, the crack formation on the surface side of the third inorganic hard coating 16 was evaluated; and for the comparative laminate of Comparative Example 1, the crack formation on the surface side of the resin substrate 10 was evaluated. The evaluation results are shown in Table 1.

[0125]

[0126] As shown in Table 1, the pencil hardness of the laminates 1 of Examples 1 and 2 is higher than that of the comparative laminate of Comparative Example 1. Therefore, it can be confirmed that the hardness of the laminates 1 of Examples 1 and 2 is improved compared with that of the comparative laminate of Comparative Example 1.

[0127] Furthermore, the number of cracks in the laminates 1 of Examples 1 and 2 was reduced compared to the comparative laminate of Comparative Example 1. Therefore, the crack reduction effect can be confirmed in the laminates 1 of Examples 1 and 2 compared to the comparative laminate of Comparative Example 1.

[0128] Explanation of reference numerals in the attached figures 1. Layered body 10 Resin substrate 12 First Inorganic Hard Coating 14 Second Inorganic Hard Coating 16 Third Inorganic Hard Coating

Claims

1. A laminated body, comprising: The first inorganic hard coating formed on the resin substrate by plasma CVD, and A second inorganic hard coating is formed on the first inorganic hard coating by plasma CVD. The refractive index of the first inorganic hard coating is greater than that of the second inorganic hard coating.

2. The laminated body according to claim 1, wherein, The first inorganic hard coating and the second inorganic hard coating are composed of SiOx, and the values ​​of x are different for each other.

3. The laminated body according to claim 1, wherein, The x value of the first inorganic hard coating composed of SiOx is less than the x value of the second inorganic hard coating composed of SiOx.

4. The laminated body according to claim 1, wherein, The thickness of the second inorganic hard coating is greater than the thickness of the first inorganic hard coating.

5. The laminated body according to claim 1, wherein, A third inorganic hard coating, formed by plasma CVD, is provided on the second inorganic hard coating. The refractive index of the third inorganic hard coating is less than that of the second inorganic hard coating.

6. The laminate according to claim 5, wherein, The third inorganic hard coating is composed of SiOx, and the value of x is different from that of the first and second inorganic hard coatings.

7. The laminate according to claim 5, wherein, The thickness of the second inorganic hard coating is greater than the thickness of the first inorganic hard coating and the third inorganic hard coating.

8. The laminate according to claim 5, wherein, The x value of the third inorganic hard coating composed of SiOx is greater than the x value of the second inorganic hard coating composed of SiOx.

9. A method for manufacturing a laminate, comprising: The first inorganic hard coating formation process, which involves forming a first inorganic hard coating on a resin substrate using plasma CVD, and The process of forming a second inorganic hard coating by plasma CVD on the first inorganic hard coating to form a second inorganic hard coating with a refractive index smaller than that of the first inorganic hard coating.

10. The method for manufacturing a laminate according to claim 9, wherein, In the plasma CVD film formation of at least one of the first inorganic hard coating and the second inorganic hard coating, the ratio of the organosilane compound to oxygen in the mixed gas is continuously varied.

11. The method for manufacturing a laminate according to claim 9, wherein, It also includes a surface modification process of irradiating the resin substrate, which is a polycarbonate substrate, with monochromatic light of wavelengths above 380 nm and below 420 nm.

12. The method for manufacturing a laminate according to claim 11, wherein, It also includes one or more of the following surface modification processes: plasma treatment, ultraviolet irradiation treatment, UV (Ultra Violet) ozone treatment, microbubble ozone water treatment, or electrolytic sulfuric acid treatment.

13. The method for manufacturing a laminate according to claim 9, comprising: A heating process that heats a laminate on a resin substrate, on which at least the first inorganic hard coating and the second inorganic hard coating are sequentially stacked, at a temperature above the temperature at which carbon contained in the carbon-containing SiOx constituting the second inorganic hard coating can be removed and below the glass transition temperature of the resin substrate.

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