Laminate and method for manufacturing a laminate

Abstract

To improve the environmental resistance of the laminated material. [Solution] The laminate 1 comprises a resin substrate 10, an intermediate layer 12 laminated on the resin substrate 10, and an inorganic hard coat layer 14 formed on the intermediate layer 12 by a dry process. The refractive index of the intermediate layer 12 is 1.8 or more and less than 2.9.

Description

[Technical Field]

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

[0002] A laminate is disclosed in which a hard coat layer is formed on a resin substrate. For example, a configuration is disclosed in which the hard coat layer is formed on the resin substrate by a dry process. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 6521584 [Patent Document 2] Patent No. 5336016 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, with conventional technology, peeling could occur when immersed in water, which sometimes led to problems with reduced environmental resistance.

[0005] The present invention has been made in view of the above, and aims to provide a laminate and a method for manufacturing a laminate that can improve environmental resistance. [Means for solving the problem]

[0006] The laminate of the embodiment comprises a resin substrate, an intermediate layer laminated on the resin substrate having a refractive index of 1.8 or more and less than 2.9, and an inorganic hard coat layer formed on the intermediate layer by a dry process. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram of an example of a laminate according to the embodiment. [Figure 2A] FIG. 2A is a diagram illustrating calculation results of Hamaker constants. [Figure 2B] FIG. 2B is a graph showing the relationship between Hamaker constant and refractive index. [Figure 3] FIG. 3 is a graph showing the relationship between the thickness of an intermediate layer and the adsorption energy between a resin base material and an inorganic hard coat layer. [Figure 4A] FIG. 4A is a schematic diagram illustrating an example of a method for producing a layered body according to an embodiment. [Figure 4B] FIG. 4B is a schematic diagram illustrating an example of a method for producing a layered body according to an embodiment. [Figure 4C] FIG. 4C is a schematic diagram illustrating an example of a method for producing a layered body according to an embodiment. [Figure 4D] FIG. 4D is a schematic diagram illustrating an example of a method for producing a layered body according to an embodiment. DESCRIPTION OF EMBODIMENTS

[0008] Details of the layered body and the method for producing the layered body according to the present embodiment will be described below with reference to the accompanying drawings. In each drawing, the same components are denoted by the same reference numerals, and duplicate descriptions may be omitted.

[0009] FIG. 1 is a schematic diagram of an example of a layered body 1 according to the present embodiment.

[0010] The layered body 1 is a layered body obtained by laminating an intermediate layer 12 and an inorganic hard coat layer 14 in this order on a resin base material 10.

[0011] The resin base material 10 is a base material formed of a resin. For example, the resin base material 10 is formed of a plastic material that is transparent to visible light.

[0012] Examples of plastic materials used in the resin substrate 10 include polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polypropylene (PP), cycloolefin polymer (COP), acrylonitrile butadiene styrene resin (ABS), and the like.

[0013] The resin substrate 10 can take the form of a film, sheet, or plate, depending on its application. The resin substrate 10 may also be an injection-molded product. In this embodiment, a plate-shaped form of the resin substrate 10 will be described as an example.

[0014] The thickness of the resin substrate 10 is not limited. The thickness of the resin substrate 10 can be adjusted according to the application of the laminate 1.

[0015] The intermediate layer 12 is a layer laminated on the resin substrate 10. The intermediate layer 12 is a layer provided between the resin substrate 10 and the inorganic hard coat layer 14, with one end face in the thickness direction in direct contact with the opposing surface of the resin substrate 10, and the other end face in the thickness direction in direct contact with the opposing surface of the inorganic hard coat layer 14.

[0016] Details of the intermediate layer 12 will be described later.

[0017] The inorganic hard coat layer 14 is a hard coat layer made of inorganic material formed on the intermediate layer 12 by a dry process.

[0018] The dry process may be either a chemical deposition method called CVD (Chemical Vapor Deposition) or a physical deposition method called PVD (Physical Vapor Deposition). In this embodiment, one example described is a hard coat layer 14 made of an inorganic material formed by plasma CVD.

[0019] For example, the inorganic hard coat layer 14 is a laminate formed by stacking a first inorganic hard coat layer 14A, a second inorganic hard coat layer 14B, and a third inorganic hard coat layer 14C in that order. The inorganic hard coat layer 14 may also be configured without the third inorganic hard coat layer 14C.

[0020] The refractive index of the first inorganic hard coat layer 14A is preferably greater than that of the second inorganic hard coat layer 14B. The refractive index of the second inorganic hard coat layer 14B is preferably greater than that of the third inorganic hard coat layer 14C.

[0021] In other words, the relationship between the refractive indices of the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C is preferably expressed by the following formula (1).

[0022] Refractive index relationship: Third inorganic hard coat layer 14C < Second inorganic hard coat layer 14B < First inorganic hard coat layer 14A ... Equation (1)

[0023] The refractive indices of the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C should be adjusted within the range that satisfies the above relationship, according to the application of the laminate 1.

[0024] Specifically, the refractive index of the first inorganic hard coat layer 14A is preferably in the range of 1.437 to 1.450, and more preferably in the range of 1.437 to 1.440. The refractive index of the second inorganic hard coat layer 14B is preferably in the range of 1.410 to 1.433, and more preferably in the range of 1.420 to 1.433. The refractive index of the third inorganic hard coat layer 14C is preferably in the range of 1.348 to 1.378, and more preferably in the range of 1.358 to 1.368.

[0025] The hardness of the inorganic hard coat layer 14 can be improved by ensuring that the refractive indices of the first inorganic hard coat layer 14A and the second inorganic hard coat layer 14B, or the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C, contained in the inorganic hard coat layer 14, satisfy the above relationship.

[0026] The refractive indices of the first inorganic hard coat layer 14A and the second inorganic hard coat layer 14B are greater than those of the third inorganic hard coat layer 14C. This indicates that the first inorganic hard coat layer 14A and the second inorganic hard coat layer 14B are closer to the state of silicone resin than the third inorganic hard coat layer 14C. Furthermore, the refractive index of the first inorganic hard coat layer 14A is greater than that of the second inorganic hard coat layer 14B. This indicates that the first inorganic hard coat layer 14A is closer to the state of silicone resin than the second inorganic hard coat layer 14B.

[0027] Unlike the glass state, the silicone resin state is viscoelastic. Therefore, the stress between the intermediate layer 12 and the inorganic hard coat layer 14 that occurs during the manufacturing of the laminate 1 using a dry process such as plasma CVD can be reduced by the first inorganic hard coat layer 14A, or the first inorganic hard coat layer 14A and the second inorganic hard coat layer 14B absorbing the difference in thermal expansion between the layers. As a result, it is possible to suppress the decrease in hardness due to crack formation in the inorganic hard coat layer 14 and improve hardness.

[0028] The refractive indices of the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C are measured by measuring the reflectance using a Hitachi High-Tech spectrophotometer at an incident angle of 15 degrees, and then fitting the measurements using an optical simulation application.

[0029] The first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C may be composed of the same components or different components. If they are composed of the same components, the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C may differ in the quantitative proportion of at least some of their components. For example, if they are composed of the same components, it is preferable that the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C are composed of SiOx.

[0030] When the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C are composed of SiOx, the values ​​of x are different from each other. Specifically, the value of x1 of the first inorganic hard coat layer 14A, which is composed of SiOx, is less than the value of x2 of the second inorganic hard coat layer 14B, which is composed of SiOx. Also, the value of x3 of the third inorganic hard coat layer 14C, which is composed of SiOx, is greater than the value of x2 of the second inorganic hard coat layer 14B, which is composed of SiOx. As x approaches 2, the properties move closer to silica from silicone resin and the hardness increases. Therefore, by satisfying the above relationship, the surface layer can be made closer to glass, and the lower layer can be made into a soft silicone resin to serve as an impact absorption layer.

[0031] In other words, the relationship between the x values ​​of the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C, all composed of SiOx, is expressed by the following equation (2).

[0032] Relationship between the x values ​​of SiOx: First inorganic hard coat layer 14A < Second inorganic hard coat layer 14B < Third inorganic hard coat layer 16...Equation (2)

[0033] The values ​​of x for the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C, which are composed of SiOx, should be adjusted according to the application of the laminate 1, within the range that satisfies the above relationship.

[0034] Specifically, the x value for the first inorganic hard coat layer 14A, composed of SiOx, is preferably in the range of 1.05 to 1.15. Furthermore, the x value for the second inorganic hard coat layer 14B, composed of SiOx, is preferably in the range of 1.2 to 1.4. Finally, the x value for the third inorganic hard coat layer 14C, composed of SiOx, is preferably in the range of 1.45 to 1.65.

[0035] The x values ​​for each of the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C, which are composed of SiOx, are measured using an EDX analyzer under EDX analysis conditions of 10K magnification.

[0036] Furthermore, the SiOx constituting each of the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C may contain carbon (C).

[0037] The thickness of the second inorganic hard coat layer 14B is preferably greater than the thickness of the first inorganic hard coat layer 14A and the third inorganic hard coat layer 14C.

[0038] In other words, the relationship between the thicknesses of the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C is preferably expressed by the following formula (3). This is because the first inorganic hard coat layer 14A is in a state similar to silicone resin and therefore has some water solubility, and because cracks tend to occur as the thickness of the third inorganic hard coat layer 14C increases.

[0039] Relationship of the thickness of the inorganic hard coat layer 14: First inorganic hard coat layer 14A and third inorganic hard coat layer 14C < Second inorganic hard coat layer 14B ... Equation (3)

[0040] The thicknesses of the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C may be adjusted according to the intended use of the laminate 1, within the range that satisfies the above relationship.

[0041] Specifically, for example, the thickness of the first inorganic hard coat layer 14A is preferably in the range of 100 nm to 500 nm, and more preferably in the range of 200 nm to 400 nm. The thickness of the second inorganic hard coat layer 14B is preferably in the range of 700 nm to 1000 nm, and more preferably in the range of 900 nm to 1000 nm. The thickness of the third inorganic hard coat layer 14C is preferably in the range of 300 nm to 600 nm, and more preferably in the range of 400 nm to 500 nm.

[0042] Next, we will explain the intermediate layer 12 in detail.

[0043] The intermediate layer 12 is a layer directly laminated on the resin substrate 10. As described above, the intermediate layer 12 is a layer provided between the resin substrate 10 and the inorganic hard coat layer 14, with one end face in the thickness direction in direct contact with the opposing surface of the resin substrate 10, and the other end face in the thickness direction in direct contact with the opposing surface of the inorganic hard coat layer 14. The opposing surface of the resin substrate 10 is the surface of both ends of the resin substrate 10 in the thickness direction that faces the inorganic hard coat layer 14 (first inorganic hard coat layer 14A). The opposing surface of the inorganic hard coat layer 14 (first inorganic hard coat layer 14A) is the surface of both ends of the inorganic hard coat layer 14 (first inorganic hard coat layer 14A) in the thickness direction that faces the resin substrate 10.

[0044] The refractive index of the intermediate layer 12 is 1.8 or more and less than 2.9. It is essential that the refractive index of the intermediate layer 12 is 1.8 or more and less than 2.9, but preferably it is 1.8 or more and 2.3 or less, and more preferably 2.3.

[0045] The refractive index of the intermediate layer 12 is measured by measuring the reflectance using a Hitachi High-Tech spectrophotometer at an incident angle of 15 degrees, and then fitting the measurement using an optical simulation application.

[0046] Examples of constituent materials for the intermediate layer 12 that satisfy the above refractive index include Nb2O5 (niobium 5-octase), ITO (indium tin oxide), CaO (calcium octase), La2O3 (lanthanum octase), and BaO (barium octase). Among these, Nb2O5 is particularly preferred as the intermediate layer 12.

[0047] The intermediate layer 12 with a refractive index within the above range is provided between the resin substrate 10 and the inorganic hard coat layer 14. This suppresses peeling of the inorganic hard coat layer 14 when the laminate 1 is immersed in water, thereby improving the environmental resistance of the laminate 1.

[0048] The environmental resistance of laminate 1 can be evaluated by immersing laminate 1 in 60°C hot water, holding it for 72 hours or more, removing it from the hot water, removing any adhering moisture, leaving it at room temperature for 1 hour, and then performing an adhesion test using the grid tape method in accordance with JIS K5400.

[0049] The reasons why it is preferable for the refractive index of the intermediate layer 12 to be within the above range will be explained in detail.

[0050] In a laminate 1 in which a resin substrate 10, an intermediate layer 12, and an inorganic hard coat layer 14 are laminated in this order, the adsorption energy W acting between the resin substrate 10 and the inorganic hard coat layer 14 via the intermediate layer 12 is expressed by the following equation (A).

[0051]

number

[0052] In equation (A), W represents the adsorption energy acting between the resin substrate 10 and the inorganic hard coat layer 14 via the intermediate layer 12. Adsorption energy is the force acting between the resin substrate 10 and the inorganic hard coat layer 14.

[0053] In formula (A), A 132 This is the Hamaker constant, which represents the van der Waals force acting between the resin substrate 10 and the inorganic hard coat layer 14 via the intermediate layer 12. In equation (A), D is the distance between the intermediate layer 12 and the inorganic hard coat layer 14. More specifically, D is the shortest distance between the opposing surfaces of the intermediate layer 12 and the inorganic hard coat layer 14.

[0054] Hamakar constant A 132 This is expressed by the following formula (B).

[0055]

number

[0056] Equation (B) can be expressed by the approximation equation (C).

[0057]

number

[0058] In equation (C), k, T, h, Ve, ε1, ε2, ε3, n1, n2, and n3 represent the following, respectively:

[0059] k: 1.381 × 10 -23 J / K (k: Boltzmann constant) T:300K (T:absolute temperature) h: 6.626 × 10⁻³⁴ J·s (h: Planck constant) v e :3×10¹⁵s⁻¹ (v e (Plasma frequency) ε1: Dielectric constant of the inorganic hard coat layer 14 ε2: Dielectric constant of resin substrate 10 ε3: Dielectric constant of the intermediate layer 12 n1: refractive index of the inorganic hard coat layer 14 n2: refractive index of the resin base material 10 n3: refractive index of the intermediate layer 12

[0060] Assuming that the laminate 1 is immersed in warm water at 60° C., Hamaker constant A representing the van der Waals force acting between the resin base material 10 and the inorganic hard coat layer 14 using formula (C) 132 is calculated to obtain the values shown in FIG. 2A.

[0061] FIG. 2A is a diagram illustrating the calculation results of the Hamaker constant A 132 when the materials shown in FIG. 2A are used as the resin base material 10, the intermediate layer 12, and the inorganic hard coat layer 14.

[0062] Furthermore, the Hamaker constant A 132 can be represented by the approximate formula shown in the following formula (D).

[0063]

Numerical formula

[0064] In formula (D), A11 is a Hamaker constant representing the van der Waals force acting between a pair of plate-shaped, parallel-arranged inorganic hard coat layers 14. A22 is a Hamaker constant representing the van der Waals force acting between a pair of plate-shaped, parallel-arranged resin base materials 10. A33 is a Hamaker constant representing the van der Waals force acting between a pair of plate-shaped, parallel-arranged intermediate layers 12.

[0065] Assuming A11 < A22, when the Hamaker constant A 132 is graphed, the graph shown in FIG. 2B is obtained.

[0066] FIG. 2B is a graph showing the relationship between the Hamaker constant and the refractive index of each material that can be used as the laminate 1. In FIG. 2B, the horizontal axis represents the square root value of the Hamaker constant A 33 or the refractive index. In FIG. 2B, the vertical axis represents the Hamaker constant A 132 .

[0067] If A33 is less than A11, and if A33 is greater than A22, the Hamakar constant A 132 The value becomes positive. Therefore, when these conditions are met, the adsorption energy acting between the resin substrate 10 and the inorganic hard coat layer 14 represents a force acting in the direction of mutual attraction, i.e., an attractive force. On the other hand, when these conditions are not met, the Hamakar constant A 132 When this value becomes negative, the adsorption energy acting between the resin substrate 10 and the inorganic hard coat layer 14 represents a force acting in the direction of separation, i.e., a repulsive force.

[0068] As explained in equation (C) above, the Hamakar constant A 132 The refractive index (n x Since the element is ) and the first term can be ignored compared to the second term, the relationship has a correlation as shown in equation (E).

[0069]

number

[0070] In formula (E), A xx This represents the Hamakar constant, and n x This represents the refractive index.

[0071] Therefore, the Hammerker constant A represents the van der Waals force acting between the resin substrate 10 and the inorganic hard coat layer 14. 132 This is the horizontal axis A in Figure 2B. 33 It can be said that a qualitative evaluation is possible by treating the square root of as the refractive index.

[0072] Figure 2B shows the Hammerkhar constants and refractive indices of polycarbonate used as the resin substrate 10, SiO2 used as the inorganic hard coat layer 14, and materials that can be used as the intermediate layer 12 and comparative intermediate layer. In Figure 2B, the numbers in parentheses represent the Hammerkhar constants of the layers made of each material.

[0073] As shown in Figure 2B, the refractive index of the polycarbonate resin substrate 10 is higher than that of water (H2O), and the Hammerker constant is 1.75 zJ. Therefore, in the case of a configuration without an intermediate layer 12, or when the Hammerker constant A of the intermediate layer 12 is... 132 If the water content is less than that of water, when the laminate 1 is immersed in water, water will penetrate between the resin substrate 10 and the intermediate layer 12, and, if the intermediate layer 12 is absent, between the resin substrate 10 and the inorganic hard coat layer 14, due to capillary action, and it is thought that at least a portion of the inorganic hard coat layer 14 will peel off.

[0074] On the other hand, the Hamakar constant A of the intermediate layer 12 132 When the temperature is higher than that of water, the state in which water does not penetrate between the resin substrate 10 and the intermediate layer 12 is more stable than the state in which water penetrates, so it is thought that water penetration is suppressed and peeling of the inorganic hard coat layer 14 is suppressed.

[0075] As shown in Figure 2A, in a laminate 1 in which an intermediate layer 12 made of Nb2O5 with a refractive index of 2.3 and an inorganic hard coat layer 14 made of polycarbonate are laminated in this order on a resin substrate 10 made of polycarbonate, the Hammerker constant A, which represents the van der Waals force acting between the resin substrate 10 and the inorganic hard coat layer 14, is higher compared to a comparative laminate that does not include the intermediate layer 12 or in which the intermediate layer 12 is water (refractive index 1.3). 132 However, it is significantly higher.

[0076] Therefore, in a laminate 1 in which an intermediate layer 12 with a refractive index of 1.8 or more and less than 2.9 is provided between the resin substrate 10 and the intermediate layer 12, peeling of the inorganic hard coat layer 14 due to immersion in water is suppressed, and the environmental resistance of the laminate 1 can be improved.

[0077] As mentioned above, the constituent materials for the intermediate layer 12 include Nb2O5, ITO, CaO, La2O3, and BaO, which satisfy the above refractive index. Among these, Nb2O5, which has the highest refractive index among them, is particularly preferred for the intermediate layer 12.

[0078] Furthermore, TiO2 with a refractive index of 2.9 has photocatalytic properties. When ultraviolet light is irradiated onto a TiO2 layer, the surface of the layer has strong oxidizing power, causing a decomposition of materials in other layers that are in contact with the surface (catalytic decomposition). In other words, if TiO2 with a refractive index of 2.9 is used as an intermediate layer, catalytic decomposition may occur in the inorganic hard coat layer 14 that is laminated in contact with the intermediate layer. Therefore, it is preferable that the refractive index of the intermediate layer 12 be less than 2.9.

[0079] The thickness of the intermediate layer 12 is preferably 1 nm or more and 5 nm or less, more preferably 1 nm or more and 4 nm or less, and particularly preferably 1 nm or more and 3 nm or less.

[0080] By having the thickness of the intermediate layer 12 within the above range, peeling of the inorganic hard coat layer 14 when the laminate 1 is immersed in water can be further suppressed.

[0081] Figure 3 is a graph showing the relationship between the thickness of the intermediate layer 12 contained in the laminate 1 and the adsorption energy between the resin substrate 10 and the inorganic hard coat layer 14 in the laminate 1. The horizontal axis of Figure 3 represents the thickness of the intermediate layer 12. The vertical axis of Figure 3 represents the adsorption energy acting between the resin substrate 10 and the inorganic hard coat layer 14 via the intermediate layer 12.

[0082] Figure 3 shows the change in adsorption energy when the thickness of the intermediate layer 12 is changed in a laminate 1 in which an intermediate layer 12 made of Nb2O5 and an inorganic hard coat layer 14 made of SiO2 are laminated in that order on a resin substrate 10 made of polycarbonate. Figure 3 shows the Hamakar constant A calculated using the above formula (D) as the adsorption energy. 132 This shows the case using this method.

[0083] As shown in Figure 3, when the thickness of the intermediate layer 12 is 5 nm or less, the adsorption energy (Hamakar constant A) acting between the resin substrate 10 and the inorganic hard coat layer 14 via the intermediate layer 12 is greater than when the thickness is greater than 5 nm. 132) rises sharply. For this reason, the thickness of the intermediate layer 12 is preferably 5 nm or less, from the viewpoint of further suppressing the peeling of the inorganic hard coat layer 14 when the laminate 1 is immersed in water.

[0084] Furthermore, Figure 3 is a graph assuming that the intermediate layer 12 has optical properties even when its thickness is 0 nm. However, in reality, since the lattice constant of Nb2O5 is about 0.4 nm, the thickness of the intermediate layer 12 needs to be 1 nm or more in order to achieve the refractive index in the above range. Also, assuming that a 0.5 nm film of Nb2O5 is deposited, the layer of Nb2O5 is a half mono layer and is therefore deposited in an island shape. For this reason, from the viewpoint of constructing a continuous thin film intermediate layer 12, it is preferable that the thickness of the intermediate layer 12 be 1 nm or more, which corresponds to one mono layer.

[0085] The thickness distribution of the intermediate layer 12 is preferably ±5% or less, more preferably ±2.5% or less, and particularly preferably ±1% or less.

[0086] The distribution of the thickness of the intermediate layer 12 represents the maximum value of the deviation in the positive and negative directions of the thickness at each of the multiple points (three or more points) across the entire region of the intermediate layer 12, relative to the average value of the thickness at each point.

[0087] The distribution of the thickness of the intermediate layer 12 is within the above range, which further suppresses the peeling of the inorganic hard coat layer 14 when the laminate 1 is immersed in water.

[0088] On the other hand, if the thickness distribution of the intermediate layer 12 is outside the above range, water can easily penetrate from areas with large differences in thickness in the intermediate layer 12 contained in the laminate 1, which may cause peeling of the inorganic hard coat layer 14. This is because areas with large differences in thickness experience large changes in adsorption energy, making them more susceptible to water penetration. For this reason, it is preferable that the thickness distribution of the intermediate layer 12 be within the above range. In particular, assuming that the intermediate layer 12 is formed by depositing Nb2O5 by sputtering, it is preferable that the difference between the maximum and minimum thickness across the entire surface of the intermediate layer 12 is 0.5 nm or less, which is 1 mono layer.

[0089] The constituent materials of the intermediate layer 12 can be confirmed using a transmission electron microscope, scanning electron microscope, etc. Furthermore, the thickness and thickness distribution of the intermediate layer 12 can be measured by measuring the reflectance of the intermediate layer 12 formed on the resin substrate 10 at an incident angle of 15 degrees using a Hitachi High-Tech spectrophotometer, and then fitting the measurement using an optical simulation application.

[0090] Next, the manufacturing method of the laminate 1 of this embodiment will be described.

[0091] Figures 4A to 4D are schematic diagrams showing an example of a manufacturing method for the laminate 1 of this embodiment.

[0092] The method for manufacturing the laminate 1 includes an intermediate layer formation step and an inorganic hard coat layer formation step. More specifically, for example, the method for manufacturing the laminate 1 includes a surface modification step, an intermediate layer formation step, an inorganic hard coat layer formation step and a heating step.

[0093] Figure 4A is an explanatory diagram of the surface modification process and the intermediate layer formation process.

[0094] First, a surface modification process is performed to modify the surface of the resin substrate 10.

[0095] In this embodiment, "surface modification" refers to a modification treatment that cleaves molecular chains present on the surface of the resin substrate 10 and generates functional groups such as hydroxyl groups, carboxyl groups, and formyl groups. Examples of surface modification treatments include monochromatic light irradiation, plasma treatment, ultraviolet irradiation, UV (Ultra Violet) ozone treatment, fine bubble ozone water treatment, or electrolytic sulfuric acid treatment. Electrolytic sulfuric acid is a solution produced by electrolyzing sulfuric acid. The modification treatment may employ only one of these treatments, or two or more treatments may be employed and carried out sequentially.

[0096] Among these various types of modification treatments, when a substrate made of polycarbonate is used as the resin substrate 10, it is preferable to use monochromatic light irradiation treatment.

[0097] In detail, the surface modification process involves irradiating the resin substrate 10, made of polycarbonate, with monochromatic light having a wavelength of 380 nm to 420 nm. Specifically, an LED (Light Emitting Diode) that emits monochromatic light of the said wavelength is used to irradiate the resin substrate 10 with the light from the LED, thereby modifying the surface of the resin substrate 10. Surface modification of the resin substrate 10 improves adhesion with the intermediate layer 12 formed on top of the resin substrate 10.

[0098] Next, an intermediate layer formation step is performed to form an intermediate layer 12 on the surface-modified resin substrate 10. Note that the surface modification step is not a mandatory step.

[0099] The intermediate layer formation process is a process of forming an intermediate layer 12 having a refractive index of 1.8 or more and less than 2.9 on a resin substrate 10 by sputtering.

[0100] In the intermediate layer formation configuration, a voltage is applied to a target containing the material constituting the intermediate layer 12, and a predetermined reactive gas and an inert gas (e.g., argon gas) for generating plasma are supplied at a predetermined flow rate to form the intermediate layer 12 on the resin substrate 10. When sputtering the intermediate layer 12 onto the resin substrate 10, it is preferable to do so while the resin substrate 10 is rotating. By forming the intermediate layer 12 by sputtering while rotating the resin substrate 10, the thickness distribution of the intermediate layer 12 can be adjusted to the above range. For the apparatus used to sputter the intermediate layer 12 while rotating the resin substrate 10, for example, the sputtering apparatus shown in Japanese Patent Application Publication No. 2022-029738 may be used.

[0101] Figures 4B to 4D are explanatory diagrams of the inorganic hard coat layer formation process.

[0102] In the inorganic hard coat layer formation process, an inorganic hard coat layer 14 is formed on the intermediate layer 12 by a dry process at a deposition temperature of 90°C or lower. By forming the inorganic hard coat layer 14 at a deposition temperature of 90°C or lower, it is possible to suppress the occurrence of cracks in the laminate 1 during film formation.

[0103] The film formation temperature for the inorganic hard coat layer 14 is preferably 60°C to 90°C, more preferably 60°C to 80°C, and particularly preferably 65°C to 75°C.

[0104] For example, the LPP-400TT manufactured by Shibaura Machine is used as the apparatus for forming the inorganic hard coat layer 14. The LPP-400TT is a CVD apparatus that uses a pulse drive remote plasma generation method. By using a forming apparatus driven by pulse drive, the inorganic hard coat layer 14 can be formed at a film deposition temperature of 90°C or lower.

[0105] Furthermore, the inorganic material such as SiOx used in the inorganic hard coat layer 14 exhibits increased hardness as the deposition temperature increases, but its adsorption and adhesion to other layers decrease. Conversely, lowering the deposition temperature of the inorganic hard coat layer 14 increases its adsorption and adhesion to other layers, but decreases its hardness. In the laminate 1 of this embodiment, an intermediate layer 12 is provided between the resin substrate 10 and the inorganic hard coat layer 14. Therefore, even when the deposition temperature of the inorganic hard coat layer 14 is set to 90°C or lower, the laminate 1 can maintain the hardness of the inorganic hard coat layer 14 while suppressing peeling of the inorganic hard coat layer 14 due to water infiltration.

[0106] The inorganic hard coat layer formation process will be explained in detail. For example, the explanation will assume a case where an inorganic hard coat layer 14 is formed on an intermediate layer 12 by stacking a first inorganic hard coat layer 14A, a second inorganic hard coat layer 14B, and a third inorganic hard coat layer 14C in that order.

[0107] Figure 4B is an explanatory diagram of the formation process of the first inorganic hard coat layer 14A. The first inorganic hard coat layer 14A, composed of, for example, SiOx, is formed on the intermediate layer 12 formed on the resin substrate 10 by plasma CVD.

[0108] Figure 4C is an explanatory diagram of the formation process of the second inorganic hard coat layer 14B. The second inorganic hard coat layer 14B, which is made of, for example, SiOx, is formed on the first inorganic hard coat layer 14A by plasma CVD.

[0109] Figure 4D is an explanatory diagram of the formation process of the third inorganic hard coat layer 14C. The third inorganic hard coat layer 14C, which is made of, for example, SiOx, is formed on the second inorganic hard coat layer 14B by plasma CVD.

[0110] In the plasma CVD method used in each of the first inorganic hard coat layer formation step, the second inorganic hard coat layer formation step, and the third inorganic hard coat layer formation step, as described above, the film formation should be carried out using a plasma CVD method with a plasma generator capable of adjusting the film formation temperature to 90°C or below.

[0111] Low-temperature plasma generators such as DC plasma, low-frequency plasma, high-frequency plasma, pulsed-wave plasma, triode structure plasma, and microwave plasma are used as plasma generators.

[0112] The inorganic hard coat layers 14 (first inorganic hard coat layer 14A, second inorganic hard coat layer 14B, third inorganic hard coat layer 14C) composed of SiOx can be formed using an organic silane compound and oxygen gas as raw materials. Relatively low molecular weight organic silane compounds such as tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), tetramethylsilane (TMS), hexamethyldisiloxane (HMDSO), tetramethyldisiloxane, and methyltrimethoxysilane can be used as organic silane compounds.

[0113] In plasma CVD film deposition, the above-mentioned organic silane compound is vaporized and mixed with oxygen gas, which is then introduced between electrodes. Power is applied using a low-temperature plasma generator to create a plasma, and a hard coat layer of SiOx containing carbon (C) is formed on the already formed lower layer.

[0114] In plasma CVD, the film quality can be altered in various ways. For example, the film quality can be changed by altering the organic silane compound or gas type, the mixing ratio of the organic silane compound and oxygen gas, or increasing or decreasing the applied power. Therefore, by controlling the mixing ratio of the organic silane compound and oxygen gas, the oxygen component (value of x) of carbon-containing SiOx can be adjusted. By adjusting the value of x of SiOx, it is possible to adjust the refractive indices of the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C to exhibit the relationship described above.

[0115] For example, when forming the second inorganic hard coat layer 14B by plasma CVD, the mixed gas of the organic silane compound and oxygen is mixed in a ratio of 6 to 110 moles of oxygen per mole of organic silane compound. By using this range of mixing ratio for the mixed gas of the organic silane compound and oxygen when forming the second inorganic hard coat layer 14B, it becomes possible to adjust the x value of SiOx in the second inorganic hard coat layer 14B to a range of 1.2 to 1.4.

[0116] Furthermore, for example, when forming the first inorganic hard coat layer 14A by plasma CVD, the mixed gas of the organic silane compound and oxygen is mixed in a ratio of 4 to 6 moles of oxygen per mole of organic silane compound. By using this mixing ratio when forming the first inorganic hard coat layer 14A, it becomes possible to adjust the x value of SiOx in the first inorganic hard coat layer 14A to a range of 1.05 to 1.15.

[0117] Furthermore, for example, when forming the third inorganic hard coat layer 14C by plasma CVD, the mixed gas of the organic silane compound and oxygen is mixed in a ratio of 10 to 20 moles of oxygen per mole of organic silane compound. By using the above-mentioned mixing ratio of the mixed gas of the organic silane compound and oxygen when forming the third inorganic hard coat layer 14C, it becomes possible to adjust the x value of SiOx in the third inorganic hard coat layer 14C to a range of 1.45 to 1.65.

[0118] The thicknesses of the first inorganic hard coat layer 14A, the second inorganic hard coat layer 14B, and the third inorganic hard coat layer 14C can be adjusted by controlling the formation time using the plasma CVD method.

[0119] Furthermore, during the deposition of at least one inorganic hard coat layer (first inorganic hard coat layer 14A, second inorganic hard coat layer 14B, third inorganic hard coat layer 14C) by plasma CVD, the mixed gas ratio of the organic silane compound and oxygen may be continuously changed. In this case, it becomes possible to construct an inorganic hard coat layer 14 in which the value of x in SiOx changes continuously, rather than in a layered structure as shown in Figure 1.

[0120] Finally, the laminate 1 is manufactured by performing a heating process.

[0121] In the heating process, the laminate, which consists of an intermediate layer 12 and an inorganic hard coat layer 14 laminated on a resin substrate 10, is heated at a predetermined heating temperature. The heating temperature should be above the temperature at which carbon contained in the inorganic hard coat layer 14 located at the position furthest from the resin substrate 10, i.e., on the surface of the laminate opposite to the resin substrate 10, can be removed, and below the glass transition temperature of the resin substrate 10.

[0122] For example, consider a case where the laminate 1 is a laminate in which an intermediate layer 12, a first inorganic hard coat layer 14A, and a second inorganic hard coat layer 14B are laminated on a resin substrate 10 in that order. In this case, the heating process is performed at a temperature above the temperature at which carbon contained in the second inorganic hard coat layer 14B can be removed, and below the glass transition temperature of the resin substrate 10.

[0123] Furthermore, consider a case where the laminate 1 is a laminate formed by laminating an intermediate layer 12, a first inorganic hard coat layer 14A, a second inorganic hard coat layer 14B, and a third inorganic hard coat layer 14C on a resin substrate 10. In this case, the heating process is performed at a temperature above the temperature at which carbon contained in the third inorganic hard coat layer 14C can be removed, and below the glass transition temperature of the resin substrate 10. A heating temperature that satisfies the above conditions is, for example, 100°C, but is not limited to this temperature.

[0124] In the heating process, by heating at a temperature above the temperature at which carbon contained in the inorganic hard coat layer 14, which is positioned furthest from the resin substrate 10, can be removed, and below the glass transition temperature of the resin substrate 10, the carbon contained in the inorganic hard coat layer 14 can be removed by the heating process, thereby increasing the stoichiometric composition of SiOx and improving hardness.

[0125] The heating time in the heating process is not limited. For example, the heating time could be between 3 hours and 240 hours, but it is not limited to this range.

[0126] The laminate 1 is formed by going through the following steps in this order, as explained using Figures 4A to 4D: surface modification step, intermediate layer formation step, inorganic hard coat layer formation step, and heating step.

[0127] As described above, the laminate 1 of this embodiment comprises a resin substrate 10, an intermediate layer 12 laminated on the resin substrate 10, and an inorganic hard coat layer 14 formed on the intermediate layer 12 by a dry process. The refractive index of the intermediate layer 12 is 1.8 or more and less than 2.9.

[0128] The intermediate layer 12, having a refractive index within the above range, is provided between the resin substrate 10 and the inorganic hard coat layer 14, thereby suppressing the peeling of the inorganic hard coat layer 14 when the laminate 1 is immersed in water.

[0129] Therefore, the laminate 1 of this embodiment can be improved in terms of its environmental resistance.

[0130] The applications of laminate 1 are not limited. For example, laminate 1 can be used in automotive lighting components, side visors, camera lenses for smartphones, helmet visors, etc. Automotive lighting components include, for example, headlight covers. [Examples]

[0131] The present invention will be described in detail below with reference to examples. However, the present invention is not limited to the following examples.

[0132] (Example 1) A polycarbonate substrate (manufactured by Mitsubishi Engineering Plastics, part number NF2000VUNS2) was prepared as the resin substrate 10. The dimensions of the resin substrate 10, the polycarbonate substrate, were 50 mm (length) x 50 mm (width) x 3 mm (thickness). The refractive index of the polycarbonate substrate was 1.618. The method for measuring the refractive index will be described later.

[0133] The surface of the resin substrate 10 was irradiated with monochromatic blue light with a wavelength of 360 nm to 405 nm using a blue LED for 30 seconds, thereby surface modifying the resin substrate 10.

[0134] An intermediate layer 12 made of Nb205 was formed on a surface-modified resin substrate 10 by sputtering.

[0135] In detail, a sputtering apparatus as shown in Japanese Patent Publication No. 2022-029738 was used. Then, with the resin substrate 10 placed in the chamber rotating, a voltage was applied to the target Nb205, and the pressure inside the chamber was increased (10 -2 ~10 -3 Sputtering of Nb205 was performed under a reduced pressure of 20 Pa, which was then increased to 20 Pa by introducing argon gas.

[0136] The thickness and thickness distribution of the intermediate layer 12 were measured by measuring the reflectance using a Hitachi High-Tech spectrophotometer at an incident angle of 15 degrees, and then fitting the results using an optical simulation application. For the thickness distribution of the intermediate layer 12, the thickness was measured at five locations across the entire surface of the intermediate layer 12. The maximum value of the positive deviation and the maximum value of the negative deviation of the thickness at each location relative to the average thickness were then calculated to determine the thickness distribution of the intermediate layer 12 relative to the average value. The measurement results are shown in Table 1.

[0137] Next, a first inorganic hard coat layer 14A was formed on the intermediate layer 12 by plasma CVD.

[0138] Specifically, using the Shibaura Machine LPP-400TT, 9.0 × 10 -3 After evacuating the chamber to below Pa, the raw material mixture was introduced into the chamber with a flow rate of 300 sccm for hexamethyldisiloxane (HMDSO) and 1800 sccm for oxygen (O2), controlling the volume ratio of HMDSO:O2 to 1:6. For film deposition, the O2 flow rate was fixed at 1300 sccm and the HMDSO flow rate at 300 sccm. Subsequently, the pulse drive was adjusted to achieve a film deposition temperature of 90°C or lower, and the plasma excitation power was set to 2200 W / cm² using a pulse power supply (75% duty cycle). 2 Plasma CVD was performed to form a first inorganic hard coat layer 14A of carbon-containing SiOx.

[0139] The thickness of the formed first inorganic hard coat layer 14A was 200 nm. The refractive index of the first inorganic hard coat layer 14A was 1.435, and the x-value of the SiO constituting the first inorganic hard coat layer 14A was 1.1. The methods for measuring the refractive index and the x-value will be described later.

[0140] Next, a second inorganic hard coat layer 14B was formed on the first inorganic hard coat layer 14A.

[0141] When forming the second inorganic hard coat layer 14B, the second inorganic hard coat layer 14B was formed under the same conditions as the first inorganic hard coat layer 14A, except that the flow rate of HMDSO, a deposition parameter, was set to 170 sccm as part of the plasma CVD method.

[0142] The thickness of the formed second inorganic hard coat layer 14B was 900 nm. The refractive index of the second inorganic hard coat layer 14B was 1.433, and the x-value of the SiO constituting the second inorganic hard coat layer 14B was 1.3. The methods for measuring the refractive index and the x-value will be described later.

[0143] Next, the laminate 1 of Example 1 was prepared by heating the laminate 1 of the resin substrate 10, the intermediate layer 12, and the inorganic hard coat layer 14 in air at 105°C for 6 hours.

[0144] (Examples 2-8) Laminates 1 of Examples 2-8 were prepared in the same manner as in Example 1, except that at least one of the following was adjusted from Laminate 1 of Example 1: the material of the resin substrate 10, the composition of the intermediate layer 12, the refractive index, the layer thickness, and the layer thickness distribution, so that they matched those shown in Table 1. The layer thickness and layer thickness distribution of the intermediate layer 12 were also measured in the same manner as in Example 1. The measurement results are shown in Table 1.

[0145] (Comparative Example 1 - Comparative Example 2) Comparative laminates for Comparative Examples 1 and 2 were prepared in the same manner as in Example 1, except that at least one of the following was adjusted for laminate 1 of Example 1: the material of the resin substrate 10, the composition of the intermediate layer 12, the refractive index, the layer thickness, and the layer thickness distribution, so that they matched those shown in Table 1. The layer thickness and layer thickness distribution of the intermediate layer 12 were also measured in the same manner as in Example 1. The measurement results are shown in Table 1.

[0146] (Measurement of the x value of SiOx) The x values ​​of SiOx constituting the first inorganic hard coat layer 14A and the second inorganic hard coat layer 14B were measured under the following conditions.

[0147] The value of x was determined from the atomic concentration of the target layer using EDX analysis under a 10K magnification condition, and this value was taken as the value of x.

[0148] (Measurement of refractive index) The refractive indices of the intermediate layer 12, the first inorganic hard coat layer 14A, and the second inorganic hard coat layer 14B were measured under the following conditions.

[0149] The refractive index was measured by using a Hitachi High-Tech spectrophotometer to measure the reflectance of the layer under the condition of an incident angle of 15 degrees. The refractive index was then determined by fitting the measurement results using an optical simulation application.

[0150] (evaluation) The environmental resistance of each of the laminates produced by Examples 1-11 and Comparative Laminates 1-3, which were manufactured through the above process, was evaluated.

[0151] Environmental resistance was evaluated by immersing laminate 1 or the comparative laminate in 60°C hot water for 160 hours and 240 hours, respectively. After removing from the hot water and removing any adhering moisture, the laminate was left at room temperature for 1 hour, and then an adhesion test was performed using the grid tape method in accordance with JIS K5400.

[0152] In the grid tape test, a grid pattern of 10x10 cuts at 1mm intervals was formed on the inorganic hard coat layer 14 using a utility knife. Then, a tape with a predetermined adhesive strength (Nichiban: Cellotape®) was applied and fixed, and then peeled off. The evaluation criteria were as follows.

[0153] <Evaluation Criteria> A: No peeling or lifting of the inorganic hard coat layer 14 is observed in any of the squares of the inorganic hard coat layer 14. B: The ratio of the area where peeling or lifting occurs to the total surface area of ​​the inorganic hard coat layer 14 is 10% or more and 30% or less. C: The ratio of the area where peeling or lifting occurs to the total surface area of ​​the inorganic hard coat layer 14 is 30% or more.

[0154] The evaluation results are shown in Table 1.

[0155] [Table 1]

[0156] As shown in Table 1, the laminates 1 of Examples 1-8 showed suppressed peeling of the inorganic hard coat layer 14 compared to the comparative laminates of Comparative Examples 1-2, confirming an improvement in environmental resistance. [Explanation of Symbols]

[0157] 1. Laminate 10 Resin substrate 12 Middle Class 14. Inorganic hard coat layer

Claims

1. Resin substrate and An intermediate layer laminated on the aforementioned resin substrate, having a refractive index of 1.8 or more and less than 2.9, An inorganic hard coat layer formed on the aforementioned intermediate layer by a dry process, A laminate comprising the following features.

2. The aforementioned intermediate layer is Nb ２ O ５ , ITO, CaO, La ２ O ３ , and BaO, consisting of at least one of the above, The laminate according to claim 1.

3. The aforementioned intermediate layer is Nb ２ O ５ Consists of, The laminate according to claim 1.

4. The thickness of the aforementioned intermediate layer is It is between 1 nm and 5 nm. The laminate according to claim 1.

5. The thickness distribution of the aforementioned intermediate layer is ±5% or less. The laminate according to claim 1.

6. The aforementioned resin substrate is Made from polycarbonate, polyethylene terephthalate, polyethylene naphthalate, polymethyl methacrylate, polypropylene, cycloolefin polymer, or acrylonitrile butadiene styrene resin. The laminate according to claim 1.

7. An intermediate layer formation step is performed on a resin substrate by sputtering to form an intermediate layer with a refractive index of 1.8 or more and less than 2.9, An inorganic hard coat layer formation process in which an inorganic hard coat layer is formed at a film formation temperature of 90°C or lower by a dry process, including, A method for manufacturing laminates.

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