Laminates with microstructured substrates and methods for producing laminates

Abstract

A laminate comprising a substrate having microstructures on its surface; and a coating formed on the substrate and encapsulating the microstructures thereon. The glass transition temperature T1 of the substrate is higher than the glass transition temperature T2 of the coating. A method for producing an ophthalmic lens comprising deforming the laminate into the shape of an ophthalmic lens by applying heat and / or pressure at a temperature below T1.

Description

Background Technology

[0001] This disclosure relates to a laminate comprising a substrate having microstructures on its surface, and a method for producing the laminate.

[0002] Lenses used in ophthalmology can have microstructured surfaces. For example, microstructures can be formed on the lens surface or embedded in the lens for purposes such as myopia control, increasing the refractive power of the lens, and / or providing antireflective properties. To manufacture ophthalmic lenses with microstructured surfaces, a film with a microstructured surface can be applied to the lens surface or embedded in the lens. The microstructured film can be treated with heat and / or pressure during post-processing before and / or after the application of the microstructured film to the lens. Due to the application of heat and / or pressure to the microstructure, the microstructures on the film surface may be damaged during post-processing. Summary of the Invention

[0003] According to the claims, this disclosure relates to a laminate and a method for efficiently manufacturing a film or lens having a microstructured surface by protecting the microstructure during post-processing.

[0004] One embodiment of this disclosure relates to a laminate comprising: a substrate having microstructures on its surface; and a coating formed on the substrate and encapsulating the microstructures thereon. The glass transition temperature T1 of the substrate is higher than the glass transition temperature T2 of the coating.

[0005] In one respect, the refractive index n1 of the substrate is different from the refractive index n2 of the coating.

[0006] In one aspect, each of the substrate and coating comprises a thermoplastic plastic, which is independently polycarbonate, thermoplastic polyurethane, polyacrylate, polyester, copolyester, polymethacrylate, polystyrene, polyamide, polysulfone, polyphenylsulfone, polyetherimide, polypentene, polyolefin, ionomer, ethylene methacrylate, cyclic olefin copolymer, acrylonitrile, styrene maleic anhydride, copolymers thereof, or derivatives or mixtures thereof. In another aspect, the substrate / coating combination is polycarbonate / polymethyl methacrylate, polysulfone / polyester, copolyester / polymethyl methacrylate, polyamide / polymethyl methacrylate, copolyester / thermoplastic polyurethane, or polyamide / polyamide.

[0007] In one respect, the peel strength between the substrate and the coating, measured according to test method ASTM D1876-01, is at least 100 g / 25 mm.

[0008] In one respect, both the substrate and the coating are transparent.

[0009] In one respect, microstructures are formed by embossing the surface of a substrate.

[0010] In one aspect, the substrate is a microlens with a microstructure for myopia control, wherein the microstructure is a Fresnel microstructure for increasing the refractive power of the substrate, or a moth-eye microstructure for providing antireflective properties to the substrate. The substrate may have a thickness from 50 μm to 2 mm.

[0011] Another embodiment of this disclosure relates to a method for producing ophthalmic lenses, the method comprising deforming the laminate into the shape of an ophthalmic lens by applying heat, pressure, or both.

[0012] Another embodiment of this disclosure relates to a method for processing a substrate having microstructures on its surface, the method comprising: forming a coating on the substrate such that the coating encapsulates the microstructures of the substrate; and deforming a laminate of the substrate and the coating by applying heat, pressure, or both. The glass transition temperature T1 of the substrate is higher than the glass transition temperature T2 of the coating.

[0013] In one aspect, the laminate is deformed at a temperature below T1 by thermoforming and / or by injection molding a hot melt polymer over the laminate.

[0014] Another embodiment of this disclosure relates to a method for producing ophthalmic lenses, the method comprising: extruding a first polymer having a glass transition temperature T1 to form a substrate; embossing the surface of the substrate to form microstructures on the surface of the substrate; extruding a second polymer having a glass transition temperature T2 to form a coating on the substrate, such that the coating encapsulates the microstructures of the substrate; and deforming a laminate of the substrate and the coating into the shape of an ophthalmic lens by applying heat, pressure, or both. The glass transition temperature T1 of the first polymer is higher than the glass transition temperature T2 of the second polymer. The laminate is deformed at a temperature below T1 by thermoforming and / or injection molding a hot-melt polymer over the laminate. Attached Figure Description

[0015] A more comprehensive understanding of the various embodiments and their many incidental advantages will be readily obtained when the following detailed description is considered in conjunction with the accompanying drawings, as a better understanding can be obtained by referring to the following detailed description.

[0016] Figure 1A The post-processing procedure (thermoforming process) on a substrate with microstructure is shown using a thermoforming machine.

[0017] Figure 1B The post-processing (injection molding) of inserts on a substrate with microstructures is shown.

[0018] Figure 2A The post-processing (thermoforming process) is shown on a laminate of a substrate and coating with microstructures using a thermoforming machine.

[0019] Figure 2B The post-processing (injection molding) of inserts on a laminate with a microstructured substrate and coating is shown.

[0020] Figure 3 An exemplary process for producing a laminate with a substrate and coating having a microstructured surface is shown. Detailed Implementation

[0021] Various embodiments of this disclosure will now be described below.

[0022] The first embodiment relates to a laminate comprising: a substrate having microstructures on its surface; and a coating formed on the substrate and encapsulating the microstructures thereon.

[0023] The substrate has microstructures on its surface. The structure and material of the substrate, as well as the shape and size of the microstructures, are not particularly limited.

[0024] In one aspect, the substrate may be a film or layer suitable for inclusion in, attachment to, or use as an ophthalmic lens.

[0025] The substrate may contain, or be made of, a polymer such as a thermoplastic polymer. Examples of thermoplastic polymers contained in or constituting the substrate include, but are not limited to, polycarbonate, thermoplastic polyurethane, polyacrylate, polyester, copolyester, polymethacrylate, polystyrene, polyamide, polysulfone, polyphenylsulfone, polyetherimide, polypentene, polyolefin, ionomer, ethylene methacrylate, cycloolefin copolymer, acrylonitrile, and styrene maleic anhydride.

[0026] Copolymers of these polymers can also be used. A copolymer can have two or more structures derived from different polymers in a single molecule. A copolymer can contain at least one structure derived from a polymer other than those mentioned above.

[0027] Derivatives of the above polymers can also be used. The derivatives may have at least one functional group that is molecularly bonded to the above polymer.

[0028] Mixtures of these polymers, copolymers, and / or derivatives may also be used. The mixture may be a resin comprising two or more different polymer molecules. The mixture may contain at least one polymer other than those described above.

[0029] The substrate may contain a variety of additives, dyes, and / or filters. Examples of additives may include, but are not limited to, heat stabilizers, release agents, HALS (hindered amine light stabilizers), and light stabilizers. Dyes may be, for example, color-balancing dyes, photochromic dyes, or dichroic dyes. Filters may be, for example, blue light-cutting dyes, UV-cutting dyes, IR-cutting dyes, or any other functional component. These additives, dyes, and filters may be used individually or in any combination.

[0030] In one embodiment, the substrate is transparent. As used herein, the term "transparent" is intended to mean that the substrate is able to transmit visible light, making an object behind the substrate visible to the naked eye. The visible light transmittance (Tv%) of the coating can be 75%-98%, preferably 80%-95%, including all ranges and subranges therebetween. The color of the substrate is not particularly limited.

[0031] The thickness of the substrate is not particularly limited and can be determined based on the application of the substrate. When the substrate is used in ophthalmic applications, the thickness (h1) of the substrate can range from 50 μm to 2 mm.

[0032] In one respect, microstructures can be structures suitable for application to ophthalmic lenses. Examples of microstructures include, but are not limited to, structures for controlling myopia; structures for increasing the refractive power of a substrate, such as Fresnel microstructures; and structures for providing antireflective properties to a substrate, such as moth-eye structures.

[0033] Microstructures can be formed on one or both surfaces of a substrate. In one embodiment, a microstructure can be formed on one surface of the substrate. Microstructures can be formed by any process or method. For example, microstructures can be formed on the surface of the substrate by embossing.

[0034] In this embodiment, the coating is formed on the substrate and encapsulates the substrate's microstructure. In one embodiment, the coating completely fills the gaps between the microstructures.

[0035] The coating may contain polymers such as thermoplastic polymers, or may be made from them. The aforementioned thermoplastic polymers, copolymers and derivatives of these polymers, and mixtures thereof may be used. The coating may also contain the aforementioned additives, dyes, and / or filters.

[0036] In one embodiment, the coating is transparent. The visible light transmittance (Tv%) of the coating can be 75%-98%, preferably 80%-95%, including all ranges and subranges therebetween. The color of the coating is not particularly limited.

[0037] In one aspect of this embodiment, the glass transition temperature (T1) of the substrate is higher than the glass transition temperature (T2) of the coating. Therefore, one or more materials of the coating can be determined based on the material of the substrate, and vice versa. Each of T1 and T2 can be from 80°C to 200°C, preferably from 85°C to 190°C, including all ranges and subranges therein. The difference between T1 and T2 can be from 10°C to 100°C, preferably from 12°C to 75°C, including all ranges and subranges therein.

[0038] For example, when the substrate is made of or contains polycarbonate, the coating may be made of or contain polymethyl methacrylate (PMMA). When the substrate is made of or contains polysulfone, the coating may be made of or contain polyester. When the substrate is made of or contains copolyester, the coating may be made of or contain PMA. When the substrate is made of or contains polyamide, the coating may be made of or contain PMA. When the substrate is made of or contains copolyester, the coating may be made of or contain thermoplastic polyurethane. Furthermore, the substrate and coating may be made of the same polymer, provided that the glass transition temperature (T1) of the substrate is higher than the glass transition temperature (T2) of the coating. For example, when the substrate is made of or contains polyamide, the coating may be made of or contain polyamide with a glass transition temperature lower than that of the polyamide in the substrate. These combinations are for illustrative purposes only, and there are no particular restrictions on the combination of materials for the substrate and the coating, as long as the glass transition temperature (T1) of the substrate is higher than the glass transition temperature (T2) of the coating.

[0039] In one respect, the refractive index (n2) of the coating differs from that of the substrate (n1). Each of n1 and n2 may be from 1.45 to 1.65, preferably from 1.49 to 1.64, including all ranges and subranges therebetween.

[0040] The coating thickness (h2) can be determined based on the size of the microstructure on the substrate surface, and / or based on the substrate thickness (h1) and the modulus of the substrate and coating.

[0041] Minimum coating thickness (h) 2，最小 It can be equal to the height of the microstructure on the substrate surface, or calculated using the following equation (1), taking the larger one:

[0042] h 2，最小 =h1×(E1 / E2) (1),

[0043] Where E1 is the modulus of the substrate and E2 is the modulus of the coating.

[0044] The coating can be thick enough that the microstructures on the substrate surface are substantially or completely embedded in the coating.

[0045] Maximum coating thickness (h) 2，最大 It is not subject to any particular restrictions and can be determined based on the application of the laminate.

[0046] The coating material can be well compatible with the substrate material, enabling strong adhesion between the coating and the substrate. In one aspect, the coating can bond to the substrate such that the peel strength between the substrate and the coating (measured according to test method ASTM D1876-01) is at least 100 g / 25 mm.

[0047] The shape and size of the laminate are not particularly restricted. When the laminate is used in ophthalmic applications, it can be in a shape and size suitable for ophthalmic lenses.

[0048] In one embodiment, the laminate is transparent. The color of the laminate is not particularly limited. When used in ophthalmic applications, the laminate in one embodiment offers high resolution.

[0049] The laminate may include at least one additional layer, provided that it does not interfere with the properties of the substrate and the coating. In one embodiment, one or more additional layers are formed on the substrate surface opposite to the surface on which the coating is formed.

[0050] When there is no coating on the substrate, applying pressure and / or heat to the substrate can deform the microstructures formed on the substrate surface. For example, when the substrate is a film or layer included in or used as an ophthalmic lens, the substrate often undergoes post-processing to deform it into a desired curve and / or shape. Post-processing can be thermoforming and / or injection molding, which is carried out by applying pressure and / or heat to the substrate using a third party, such as a thermoforming machine during thermoforming and an insert during injection molding. Figure 1A The thermoforming process using a thermoforming machine is shown, and Figure 1B The injection molding process using inserts is illustrated. Without a coating, the pressure applied to the microstructure by the thermoforming machine or inserts, as well as the heat applied during the thermoforming or injection molding process, can damage the microstructure.

[0051] On the other hand, when a coating is provided on the substrate, the coating can protect the microstructure from the stress and / or heat applied during post-processing. Figure 2A The thermoforming process using a thermoforming machine is shown, and Figure 2B The injection molding process using inserts is illustrated. Due to the coating, pressure and heat are not directly applied to the microstructure, and the microstructure can be protected during these post-processing steps.

[0052] In this embodiment, the glass transition temperature (T1) of the substrate is higher than the glass transition temperature (T2) of the coating. When post-processing is performed at a temperature around T2 and lower than T1, the coating can deform, while the microstructures formed on the substrate surface can remain unchanged. As used herein, "a temperature around T2" can be T2 ± 15°C, preferably T2 ± 10°C, more preferably T2 ± 5°C, more preferably T2 ± 3°C, and particularly preferably T2 ± 1°C, and includes the exact temperature T2.

[0053] The second embodiment relates to a method for producing ophthalmic lenses, the method comprising: deforming the laminate into the shape of an ophthalmic lens by applying heat, pressure or both.

[0054] Deformation can be achieved, for example, through thermoforming using a thermoforming machine or through injection molding using inserts. During deformation, the laminate can be inserted into a mold, thus applying pressure directly to the coating of the laminate. Alternatively, a polymer lens can be inserted into the mold along with the laminate, allowing the laminate and polymer lens to be injection molded together. The polymer lens can be made of or contain the material of the substrate. The laminate can also be inserted into the mold close to an insert, and the thermoplastic polymer melt can be injection molded onto the laminate.

[0055] Deformation can be performed at a temperature below the glass transition temperature (T1) of the substrate. In one embodiment, deformation can be performed at a temperature around the glass transition temperature (T2) of the coating and below the glass transition temperature (T1) of the substrate. By performing deformation at this temperature, the laminate can be deformed while the microstructures formed on the substrate surface remain unchanged.

[0056] The pressure is not particularly limited, as long as it allows the laminate to deform into the desired shape at the temperature applied during the deformation process.

[0057] The third embodiment relates to a method for processing a substrate having microstructures on its surface.

[0058] First, a coating is formed on a substrate, such that the coating encapsulates the substrate's microstructure. In one embodiment, the coating completely fills the gaps in the microstructure.

[0059] The substrate in the first embodiment described above can be used as the substrate in this embodiment. The coating formed on the substrate in this embodiment can have the material, structure, and properties of the coating in the first embodiment described above. Any material can be used to form the coating, as long as the glass transition temperature (T1) of the substrate is higher than the glass transition temperature (T2) of the coating.

[0060] Second, the laminate of substrate and coating is deformed by applying heat, pressure, or both.

[0061] Deformation can be achieved, for example, through thermoforming using a thermoforming machine or through injection molding using inserts. During deformation, the laminate can be inserted into a mold, thus applying pressure directly to the coating of the laminate. Alternatively, a polymer lens can be inserted into the mold along with the laminate, allowing the laminate and polymer lens to be injection molded together. The polymer lens can be made of or contain the material of the substrate. The laminate can also be inserted into the mold close to an insert, and the thermoplastic polymer melt can be injection molded onto the laminate.

[0062] Deformation can be performed at a temperature below the glass transition temperature (T1) of the substrate. In one embodiment, deformation can be performed at a temperature around the glass transition temperature (T2) of the coating and below the glass transition temperature (T1) of the substrate. By deforming the laminate at this temperature, the laminate can be deformed while the microstructures formed on the substrate surface remain unchanged.

[0063] The pressure is not particularly limited, as long as it allows the laminate to deform into the desired shape at the temperature applied during the deformation process.

[0064] The fourth embodiment relates to a method for producing ophthalmic lenses. Figure 3 An exemplary process for producing ophthalmic lenses is shown.

[0065] First, a first polymer with a glass transition temperature T1 is extruded to form a substrate. Figure 3 The medium indicates a high Tg membrane.

[0066] The first polymer may be a thermoplastic polymer contained in or constituting the substrate of the laminate of the first embodiment described above. The first polymer may be a copolymer or derivative of those thermoplastic polymers, or a mixture thereof. The first polymer may contain at least one polymer other than the polymers, copolymers, and mixtures described above. The first polymer may also contain the additives, dyes, and / or filters described above.

[0067] Second, the surface of the substrate is embossed to form microstructures on the substrate surface. Figure 3 An embossing roller is shown for embossing the surface of a formed substrate. Figure 3 In the process, the substrate is moved from left to right, so that the surface of the substrate is embossed by the embossing roller.

[0068] Embossing can be performed at a temperature around the glass transition temperature (T1) of the first polymer. As used herein, "a temperature around T1" can be T1 ± 15°C, preferably T1 ± 10°C, more preferably T1 ± 5°C, more preferably T1 ± 3°C, and particularly preferably T1 ± 1°C, and includes the exact temperature T1.

[0069] Figure 3 The illustration shows embossing on one surface of a substrate, but embossing can be performed on both surfaces of the substrate.

[0070] Microstructures formed by embossing are not particularly limited, as long as they are suitable for application to ophthalmic lenses. Examples of microstructures include, but are not limited to, structures for controlling myopia; structures for increasing the refractive power of a substrate, such as Fresnel microstructures; and structures for providing antireflective properties to a substrate, such as moth-eye structures. In one embodiment, one surface of the substrate is embossed.

[0071] Third, a second polymer with a glass transition temperature T2 is extruded to form a coating on the substrate, thereby encapsulating the microstructure of the substrate. Figure 3 The coating to be formed by extruding a second polymer is shown (in) Figure 3 A low-Tg film (indicated by the middle) is applied to the surface of a substrate on which microstructures are formed, and pressure is applied using a roller to bond the coating to the substrate and encapsulate the microstructures. The coating can be applied to the microstructured surface of the substrate at a temperature around the glass transition temperature (T2) of the second polymer. In one embodiment, the coating is pressed onto the substrate while being heated at a temperature below T1 (e.g., around T2), such that the second polymer completely fills the gaps between the microstructures without deforming the microstructures of the substrate.

[0072] The second polymer can be any thermoplastic polymer, as long as its glass transition temperature (T2) is lower than that of the first polymer (T1). For example, the thermoplastic polymer used as the first polymer can also be used as the second polymer.

[0073] Fourth, by applying heat, pressure, or both, the laminate of the substrate and coating is deformed into the shape of an ophthalmic lens.

[0074] Deformation can be achieved, for example, through thermoforming using a thermoforming machine or through injection molding using inserts. During deformation, the laminate can be inserted into a mold, thus applying pressure directly to the coating of the laminate. Alternatively, a polymer lens can be inserted into the mold along with the laminate, allowing the laminate and polymer lens to be injection molded together. The polymer lens can be made of or contain the material of the substrate. The laminate can also be inserted into the mold close to an insert, and the thermoplastic polymer melt can be injection molded onto the laminate.

[0075] Deformation can be performed at a temperature below the glass transition temperature (T1) of the first polymer. In one embodiment, deformation can be performed at a temperature approximately equal to and below the glass transition temperature (T2) of the second polymer and below the glass transition temperature (T1) of the first polymer. By performing deformation at this temperature, the laminate can be deformed while the microstructures formed on the substrate surface remain unchanged.

[0076] The pressure is not particularly limited, as long as it can deform the laminate into the desired ophthalmic lens shape at the temperature applied during the deformation process.

[0077] Example

[0078] The following examples are illustrative and do not limit the embodiments of the invention in any way.

[0079] Example 1: Laminate of polycarbonate (PC) substrate and polymethyl methacrylate (PMMA) coating

[0080] 1-1: Table 1 below summarizes the glass transition temperature (Tg), refractive index (RI), and visible light transmittance (Tv%) of polycarbonate (PC) and polymethyl methacrylate (PMMA). PC and PMMA are compatible with each other and can form strong adhesion between their interfaces.

[0081] Table 1

[0082] supplier Tg (°C) RI Tv% PC Teijin Co., Ltd. 149 1.59 89 PMMA Evonik 100 1.49 92

[0083] 1-2: PC / PMMA bilayer film extrusion

[0084] First, the PC film is extruded using a single-screw extruder at 255°C, and then embossed at approximately 149°C to create microstructures on its surface. Because the embossing is performed at the softening point of the PC, high-precision replication is achieved.

[0085] The PMMA film was then laminated onto the PC film at 100°C to encapsulate the microstructures. Since PMMA is flexible and deformable at its Tg, it completely fills the gaps between the microstructures. The microstructures are intact encapsulated by PMMA without being damaged or deformed because PC remains rigid at 100°C, below its Tg.

[0086] 1-3: Thermoforming of PC / PMMA double-layer film

[0087] The PC / PMMA bilayer film prepared in steps 1-2 was then thermoformed to the target curvature at 100°C. The microstructure remained intact after thermoforming because PC is rigid at 100°C, thanks to its high Tg of 149°C.

[0088] 1-4: PMMA lenses are encapsulated and molded onto a PC / PMMA double film.

[0089] The thermoformed PC / PMMA bilayer film prepared in steps 1-3 is placed inside a mold at a temperature slightly below 100°C. PMMA is injection molded onto the PC / PMMA bilayer film, clamped under high pressure, and then cooled. The resulting lens is ejected from the mold. This produces an ophthalmic lens with a high-precision microstructure.

[0090] Example 2: Laminate of polysulfone (PSU) substrate and copolyester (Co-PEST) coating

[0091] 2-1: Table 2 below summarizes the glass transition temperature (Tg), refractive index (RI), and visible light transmittance (Tv%) of polysulfone (PSU) and copolyester (Co-PEST). PSU and Co-PEST are compatible with each other and can form strong adhesion between their interfaces.

[0092] Table 2

[0093]

[0094] 2-2: PSU / Co-PEST bilayer film extrusion

[0095] The PSU film is first extruded using a single-screw extruder at 350°C, and then embossed at approximately 185°C to create microstructures on its surface. Because the embossing is performed at the softening point of the PSU, high-precision replication is achieved.

[0096] The Co-PEST film was then laminated onto the PSU film at 115°C to encapsulate the microstructures. Since PMMA is flexible and deformable at its Tg, the Co-PEST completely filled the gaps between the microstructures. The microstructures were intactly encapsulated by the Co-PEST without being damaged or deformed because the PSU remains rigid at 115°C, below its Tg.

[0097] 2-3: PSU / Co-PEST bilayer film thermoforming

[0098] The PSU / Co-PEST bilayer film prepared in step 2-2 was then thermoformed to the target curvature at 115°C. The microstructure remained intact after thermoforming because PSU is rigid at 115°C, thanks to its high Tg of 185°C.

[0099] 2-4: Co-PEST lenses are molded by overlaying on a PSU / Co-PEST double coating.

[0100] The thermoformed PSU / Co-PEST bilayer film prepared in steps 2-3 is placed inside a mold at a temperature slightly below 115°C. Co-PEST is injection molded onto the PSU / Co-PEST bilayer film, clamped under high pressure, and then cooled. The resulting lens is ejected from the mold. This produces an ophthalmic lens with a high-precision microstructure.

[0101] Example 3: Laminate of copolyester (Co-PEST) substrate and polymethyl methacrylate (PMMA) coating

[0102] Table 3 below summarizes the glass transition temperature (Tg), refractive index (RI), and visible light transmittance (Tv%) of copolyester (Co-PEST) and polymethyl methacrylate (PMMA).

[0103] Table 3

[0104] supplier Tg (°C) RI Tv% Co-PEST Eastman Chemical Company 113 1.57 90 PMMA Evonik 100 1.49 92

[0105] Example 4: Laminate of polyamide (PA) substrate and polymethyl methacrylate (PMMA) coating

[0106] Table 4 below summarizes the glass transition temperature (Tg), refractive index (RI), and visible light transmittance (Tv%) of polyamide (PA) and polymethyl methacrylate (PMMA).

[0107] Table 4

[0108] supplier Tg (°C) RI Tv% polyamide Evonik 130 1.59 89 PMMA Evonik 100 1.49 92

[0109] Example 5: Laminate of copolyester (Co-PEST) substrate and thermoplastic polyurethane (TPU) coating

[0110] Table 5 below summarizes the glass transition temperature (Tg), refractive index (RI), and visible light transmittance (Tv%) of copolyester (Co-PEST) and thermoplastic polyurethane (TPU).

[0111] Table 5

[0112] supplier Tg (°C) RI Tv% Co-PEST Eastman Chemical Company 113 1.57 90 TPU Lubrizol 90 1.60 89

[0113] Example 6: Laminate of high Tg polyamide (PA) substrate and low Tg polyamide (PA) coating

[0114] Table 6 below summarizes the glass transition temperature (Tg), refractive index (RI), and visible light transmittance (Tv%) of polyamides with different Tg values.

[0115] Table 6

[0116] supplier Tg (°C) RI Tv% PA EMS-Grivory 162 1.63 87 PA Evonik 125 1.52 91

[0117] Obviously, given the foregoing disclosure, many modifications and variations of the embodiments of the present invention are possible. Therefore, it should be understood that, within the scope of the appended claims, the embodiments may be implemented in ways different from those specifically described herein.

Claims

1. A laminate, the laminate comprising: Its surface has a microstructure substrate; and A coating formed on the substrate and encapsulating the microstructure of the substrate. The glass transition temperature T1 of the substrate is higher than the glass transition temperature T2 of the coating, and The substrate comprises polysulfone and the coating comprises polyester, or The substrate comprises a copolyester and the coating comprises polymethyl methacrylate, or The substrate comprises polyamide and the coating comprises polymethyl methacrylate, or The substrate comprises a copolyester and the coating comprises thermoplastic polyurethane, or The substrate contains polyamide and the coating contains polyamide.

2. The laminate as claimed in claim 1, wherein, The refractive index n1 of the substrate is different from the refractive index n2 of the coating.

3. The laminate as claimed in claim 1, wherein, The peel strength between the substrate and the coating, measured according to test method ASTM D1876-01, is at least 100 g / 25 mm.

4. The laminate as claimed in claim 1, wherein, The substrate and the coating are transparent.

5. The laminate as claimed in claim 1, wherein, The microstructure is formed by embossing the surface of the substrate.

6. The laminate as claimed in claim 1, wherein, The substrate is a microlens with the microstructure for myopia control, the microstructure being a Fresnel microstructure for increasing the refractive power of the substrate, or a moth-eye microstructure for providing antireflective properties to the substrate.

7. The laminate as claimed in claim 1, wherein, The substrate has a thickness ranging from 50 µm to 2 mm.

8. A method for producing an ophthalmic lens, the ophthalmic lens comprising a laminate according to any one of claims 1 to 7, wherein the method comprises: The laminate is deformed into the shape of the ophthalmic lens by applying heat, pressure, or both.

9. The method of claim 8, wherein the method comprises: A first polymer having a glass transition temperature T1 is extruded to form a matrix; Embossing is performed on the surface of the substrate to form microstructures on the surface of the substrate; A second polymer having a glass transition temperature T2 is extruded to form a coating on the substrate, such that the coating encapsulates the microstructure of the substrate to form a laminate; and Perform the deformation steps as defined in claim 8. The laminate is deformed at temperatures below T1 by thermoforming and / or by injection molding a hot melt polymer over the laminate.

10. A method for processing a substrate having a microstructure on its surface, the method comprising: A coating is formed on the substrate such that the coating encapsulates the microstructure of the substrate; and The laminate of the substrate and the coating is deformed by applying heat, pressure, or both. The glass transition temperature T1 of the substrate is higher than the glass transition temperature T2 of the coating, and The substrate comprises polysulfone and the coating comprises polyester, or The substrate comprises a copolyester and the coating comprises polymethyl methacrylate, or The substrate comprises polyamide and the coating comprises polymethyl methacrylate, or The substrate comprises a copolyester and the coating comprises thermoplastic polyurethane, or The substrate contains polyamide and the coating contains polyamide.

11. The method of claim 10, wherein, At temperatures below T1, the laminate is deformed by thermoforming and / or by injection molding a hot melt polymer over the laminate.

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