Composite mold for manufacturing microstructured thermoset articles, manufacturing method and method for obtaining the mold

Abstract

A composite mold for manufacturing a thermoset optical article that can be used as an ophthalmic lens substrate and comprises a microstructured main surface, a method for manufacturing such a thermoset optical article, and a method for obtaining the composite mold. The composite mold (1) comprises: • an inorganic first outer mold part (2) having a first inner surface (2a), and • an organic molding film (4) that is detachably bonded to the first inner surface (2a) and has a microstructured pattern configured to directly form said microstructured main surface after casting a thermoset material (6) in contact with the organic molding film (4). The organic molding film (4) is hydrophobic at least on said microstructured pattern and has a thickness between 10 nm and 500 pm.

Description

Technical Field

[0001] This invention relates to a composite mold for manufacturing thermoset optical articles that can be used as ophthalmic lens substrates and include microstructured main surfaces, a method for manufacturing such thermoset optical articles, and a method for obtaining the composite mold. The invention is particularly applicable to ophthalmic lenses comprising microstructures configured to control myopia. Background Technology

[0002] In a known manner, a thermosetting ophthalmic lens substrate with a microstructured main surface can be cast into the cavity of an inorganic glass mold, the inner surface of which has a microstructure pattern configured to impart a desired microstructure to the main surface of the cast thermosetting material after curing.

[0003] The main drawback of this casting method is that the microstructured inorganic molds are frequently damaged and eventually scrapped due to repeated cleaning and / or repolishing to suppress contamination from continuous demolding of thermosetting materials. These molds can also sometimes break if not handled properly by the operator. The scrap / breakage rate can reach as high as 0.3% of the microstructured molds used. Given their very high cost, the applicant has previously attempted to overcome this drawback.

[0004] WO 99 / 29494A1 relates to a method for obtaining an ophthalmic lens comprising a functional microstructure on its surface, the method comprising the step of transferring the microstructure from a mold to a lens surface, the inner surface of which carries the microstructure and has a vision-correcting geometry. The mold may be a composite mold comprising a metal or plastic insert having a surface in which the functional microstructure is formed, the insert preferably being conformed to the mold surface having the vision-correcting geometry by an adhesive, the composite mold being made of inorganic glass. The insert may be initially shaped to have the desired vision-correcting geometry and fixed to the corresponding mold surface, or may initially have a planar shape and then deform to conform to the vision-correcting geometry surface of the mold.

[0005] A disadvantage of this method of coating the inner surface of the mold with metal or plastic inserts may be that these adhesive inserts may not be suitable in certain situations:

[0006] - Fully conforms to the microstructure of the inorganic glass mold, especially because the glued inserts are relatively thick.

[0007] - Completely (i.e., chemically and thermally) resistant to the casting of thermosetting materials for ophthalmic lenses, and

[0008] - After the thermosetting material is cast and cured into the mold, it can be easily peeled off from the mold surface and / or the thermosetting material because the adhesion between the insert and either the mold surface or the cast material is too good. Summary of the Invention

[0009] One object of the present invention is to overcome at least the disadvantages mentioned above by providing a composite mold for manufacturing thermosetting optical articles that can be used as ophthalmic lens substrates and include microstructured main surfaces. The composite mold is manufactured by casting thermosetting material into a mold cavity. The composite mold includes:

[0010] - An inorganic first external mold component, the inorganic first external mold component having a first inner surface, and

[0011] - An organic molding film, which is separably bonded to a first inner surface and has a microstructured pattern, the microstructured pattern being configured to form the microstructured main surface directly after a thermosetting material is cast in contact with the organic molding film.

[0012] This goal was achieved because the inventors have just discovered that if a specific organic molding film is incorporated into this inorganic first outer mold component in a defined manner, a composite mold can be obtained that better protects the inorganic first outer mold component from the effects of repeated casting, curing, and demolding of thermosetting materials, thereby increasing the durability of the inorganic mold component and particularly improving the demolding property of the cast and cured thermosetting article from the composite mold (i.e., the ability to be easily removed from the composite mold during the final demolding step), while maintaining the original design pattern of the microstructure designed in the composite mold.

[0013] According to the present invention, the organic molded film is hydrophobic at least on the microstructured pattern and has a thickness between 10 nm and 500 μm.

[0014] It should be noted that this arrangement of the organic molding film and the inorganic first outer mold component allows the inorganic first outer mold component to be protected like a shielding film by preventing any contact between the cast and cured thermosetting material and the inorganic first outer mold component. This film is detachably bonded (i.e., removably attached) to the inorganic first outer mold component.

[0015] Therefore, damage to the inorganic first outer mold component due to repeated and rigorous cleaning and repolishing processes is avoided. These processes are designed to suppress contamination from repeated casting-curing-demolding steps, which are indeed very demanding on the first inner surface of the inorganic first outer mold component. This minimizes or at least significantly delays the scrapping of such inorganic first outer mold components, which are very expensive when they have their original microstructure.

[0016] It should also be noted that, since the organic molding film is configured to satisfactorily conform to the microstructures that can be designed in the inorganic first outer mold component, and especially due to its low thickness, the composite mold of the present invention allows for further improvement of the thermosetting microstructured lens material, while, particularly due to its application technique and hydrophobicity, it can be easily peeled off from the inorganic first outer mold component and the cast thermosetting material, thereby providing good conformal molding / release capability for microstructured patterns.

[0017] It can be further noted that the organic molding film of the present invention can be of the single-layer or multi-layer type, and can be:

[0018] - Completely hydrophobic (i.e., throughout its entire thickness), or

[0019] - Only the inner surface layer of the organic molded film defining the microstructured pattern designed to contact the thermosetting material to be cast is hydrophobic. This hydrophobic inner surface layer may be obtained by spraying onto an underlying organic layer, which may be hydrophilic or less hydrophobic, as explained below.

[0020] Preferably, the organic molded film of this composite mold exhibits a water contact angle of greater than 100°, preferably greater than 110°, and more preferably greater than 120° on at least the microstructured pattern (which demonstrates significantly high hydrophobicity), and a thickness between 1 μm and 100 μm, more preferably between 10 μm and 90 μm.

[0021] As mentioned above, the high hydrophobicity of the organic molding film, at least on its microstructured inner surface layer, is specifically designed to further facilitate the demolding process of the thermosetting material cast in contact with this microstructured inner surface layer, thereby allowing for satisfactory peeling of the thermosetting article from the composite mold.

[0022] According to other advantageous features of the invention, the organic molded film may be based on at least one polymer selected from elastomers, thermoplastic polymers and thermosetting polymers, and the Young's modulus measured according to ASTM D882-12 is preferably between 100 MPa and 4000 MPa, and more preferably between 200 MPa and 2000 MPa.

[0023] According to a first embodiment of the present invention, the organic molding film is based on at least one crosslinked elastomer. In the case of the completely hydrophobic organic molding film described above, the at least one crosslinked elastomer is preferably selected from silicone rubbers, such as two-component polydimethylsiloxane (PDMS), and polyurethane rubbers, such as two-component liquid urethane rubber.

[0024] According to a second embodiment of the invention, the organic molding film is based on at least one thermosetting polymer. In the case of the completely hydrophobic organic molding film described above, the at least one thermosetting polymer is preferably selected from thiol-olefin thermosetting materials, such as one-component liquid photopolymer adhesives, and thermosetting polyurethanes.

[0025] According to a third embodiment of the invention, the organic molding film is based on at least one thermoplastic polymer. In the case of the completely hydrophobic organic molding film described above, the at least one thermoplastic polymer is preferably selected from fluorinated polymers, such as terpolymers of tetrafluoroethylene, hexafluoropropylene and vinylidene fluoride, and thermoplastic polyurethane (TPU).

[0026] According to these three embodiments of the invention, the organic molded film may alternatively be based on at least one crosslinked elastomer, thermosetting polymer or thermoplastic polymer as defined above, and the organic molded film may not be hydrophobic, taking into account the hydrophobic inner surface layer of the film that can be sprayed onto the polymer underlayer of the film.

[0027] According to another aspect of the invention, an inorganic first outer mold component, for example, made of inorganic glass, may have a first inner surface comprising microstructures, to which a first side of an organic molding film is separably bonded without an adhesive, the organic molding film having the microstructures adhered to the first side and having an opposite second side forming the microstructured pattern.

[0028] Furthermore, the composite mold further includes an inorganic second outer mold component having a second inner surface opposite to the first inner surface, and the mold cavity is defined between the organic molded film and the second inner surface.

[0029] It can be noted that the inorganic first outer mold component may include inorganic materials other than inorganic glass or be made of inorganic materials other than inorganic glass, such as metallic materials or non-metallic materials that are not plastic (e.g., not organic polymers).

[0030] It can also be noted that, according to the aspects mentioned above, the inorganic first outer mold component includes the microstructure to which the organic molding film is separably bonded (non-adhesively bonded), and the bonding interface between the inorganic first outer mold component and the film (which may involve chemical bonds or not) is selected to be sufficiently weak or at most mean moderate adhesion so that the film can be easily detached from the inorganic first outer mold component after the thermosetting material has been cast and cured in the mold cavity.

[0031] According to a preferred embodiment of the invention, which is common to all the foregoing features of the invention, the first inner surface of the inorganic first outer mold component, the first inner surface including the microstructure to which the organic molding film is separably bonded (non-adhesively bonded), may have the first inner surface, the first inner surface being recessed (even if another geometry can be used), and the thickness of the organic molding film may be in the range of 1 / 10 to 1 / 100 (even more preferably 1 / 20 to 1 / 50 of the average amplitude of the microstructure of the inorganic first outer mold component).

[0032] It can be noted that this thickness ratio of the organic molded film to the average amplitude of the microstructure does not affect the optical properties of the original microstructure designed.

[0033] Another object of the present invention is to provide a method for manufacturing thermosetting optical articles that can be used as ophthalmic lens substrates and include, for example, a microstructured main surface configured to control myopia. The method is easy to implement and, taking into account the casting, curing and demolding steps, can impart excellent chemical and mechanical properties to the composite mold.

[0034] According to the present invention, this method includes:

[0035] a) Thermosetting material is cast into the cavity of the composite mold as defined above, such that the thermosetting material contacts the organic molding film and the second inner surface of the inorganic second outer mold component opposite to the first inner surface, but does not contact the first inner surface.

[0036] b) To solidify the thermosetting material cast into the mold cavity; and

[0037] c) Demolding the molded thermosetting material obtained in step b) includes peeling the molded thermosetting material from the organic molded film, such that the microstructured pattern of the organic molded film directly forms the microstructured main surface of the obtained thermosetting optical article.

[0038] It should be noted that the second inner surface of the composite mold that comes into contact with the cast thermosetting material is a complementary inorganic second outer mold component, which is part of the composite mold and closes together with the inorganic first outer mold component during operation. This second inorganic inner surface can be convex relative to the recessed first inner surface mentioned above, for example, made of inorganic glass (even if other inorganic materials can be used).

[0039] It can also be noted that the manufactured thermosetting optical articles are advantageously designed as substrates for forming ophthalmic lenses, which can be corrective lenses, for example, for treating or controlling not only myopia, but also hyperopia, astigmatism and presbyopia.

[0040] Preferably, an organic molding film is selected to resist erosion from thermosetting materials during casting step a), and it is selected from:

[0041] - Cyclic olefin copolymers, such as ethylene / norbornene or ethylene / cyclopentadiene copolymers.

[0042] - Homopolymers and copolymers of allyl carbonate from linear or branched aliphatic or aromatic polyols, such as homopolymers of diethylene glycol bis(allyl carbonate).

[0043] -Optional homopolymers and copolymers of (meth)acrylic acid and its esters derived from bisphenol A,

[0044] - Homopolymers and copolymers of thio(meth)acrylic acid and its esters,

[0045] -Optionally derived from allyl esters of bisphenol A or phthalic acid, and homopolymers and copolymers of allyl aromatic compounds such as styrene.

[0046] A copolymer of urethane and thiourethane.

[0047] - Homopolymers and copolymers of epoxy resins, and

[0048] - Homopolymers and copolymers of sulfides, disulfides and cyclic sulfides.

[0049] More preferably, an organic molding film is selected to avoid erosion by thermosetting materials during casting step a), which is:

[0050] - Homopolymers or copolymers of allyl carbonate from linear or branched aliphatic or aromatic polyols, even more preferably homopolymers of diethylene glycol bis(allyl carbonate), such as those named or

[0051] - Polyurethane copolymers, such as the so-called "MR8", "MR"7 and "1.74" lenses.

[0052] According to another aspect of the present invention, a method for obtaining a composite mold as defined above includes:

[0053] A) Provides a polymer composition that is hydrophobic or coated with a hydrophobic surface layer and capable of forming an organic molding film to be separably bonded to an inorganic first outer mold component, the polymer composition being resistant to erosion by the thermosetting material to be cast.

[0054] B) Applying the polymer composition to the inner surface of the inorganic first outer mold component to form a precursor layer for the organic molding film, and

[0055] C) The applied precursor layer is treated to form an organic molding film with a thickness between 10 nm and 500 μm, preferably between 1 μm and 100 μm, and the surface tension of the organic molding film is such that it can peel off a cast and cured thermosetting optical article.

[0056] For example, the inner surface of an inorganic first outer mold component formed of inorganic glass includes a microstructure, to which an organic molding film is bonded in steps B) and C) to form the microstructured pattern.

[0057] According to a first exemplary embodiment of the present invention, the polymer composition comprises a solution containing a solvent and at least one polymer selected from elastomers, thermoplastic polymers and thermosetting polymers, and step B) comprises coating the solution onto the inner surface of the inorganic first outer mold component, preferably by spin coating, spray coating or dip coating.

[0058] According to a first exemplary embodiment of the present invention, step C) may include:

[0059] - For example, crosslinking the precursor layer under heat and / or ultraviolet radiation (e.g., by curing the precursor layer), preferably in the case where at least one polymer is selected from elastomers and thermosetting polymers, or

[0060] - Evaporate the solvent, preferably when at least one polymer is selected from thermoplastic polymers and spin-coated in step B).

[0061] According to a second exemplary embodiment of the present invention, when the hydrophobic polymer composition is solvent-free and preferably when at least one polymer is selected from thermoplastic polymers, steps B) and C) include microthermoforming the hydrophobic polymer composition by compressing the microstructure of the inner surface of the inorganic first outer mold component using pressure and / or vacuum.

[0062] It can be noted that these methods of obtaining composite molds of the present invention advantageously allow for the high-fidelity replication of the original microstructure shape of the inorganic first outer mold component, while providing moderate adhesion to it for detachment.

[0063] In this specification, the microstructures forming the microstructured main surface of the ophthalmic lens substrate may include microlenses. Microlenses may form protrusions and / or depressions on the main surface to which they are disposed. The contours of the microlenses may be circular or polygonal, such as hexagonal.

[0064] More specifically, a small lens can be a microlens. A microlens can be spherical, toric, or have an aspherical shape, and can be rotationally symmetric or non-rotationally symmetric. A microlens can have a single focal point, or cylindrical power, or be nonfocal.

[0065] In a preferred embodiment, a microlens or pinhole can be used to prevent the progression of myopia or hyperopia. In this case, the base lens substrate includes a base lens that provides optical power for correcting myopia or hyperopia, and respectively, if the wearer is myopic, the microlens or pinhole can provide optical power greater than that of the base lens, or if the wearer is hyperopic, the microlens or pinhole can provide optical power less than that of the base lens.

[0066] A microlens or small lens can also be a Fresnel structure, a diffraction structure defining each Fresnel structure, a permanent technical protrusion, or a phase-shifting element. A microlens can also be a refractive optical element such as a microprism and a light-diffusing optical element such as a small protrusion or cavity, or any type of element that creates roughness on a substrate. It can also be a π-Fresnel microlens as described in US 2021109379 A1, i.e., a Fresnel microlens with a π phase jump in the phase function at the nominal wavelength, as opposed to a single-focus Fresnel lens with multiple values ​​of 2π for the phase jump. Such microlenses include structures with discontinuous shapes. In other words, the shape of such a structure can be described by a height function that exhibits discontinuity in distance from the reference plane of the principal surface of the ophthalmic lens to which the microlens belongs, or a derivative exhibiting discontinuity.

[0067] The microlens can have an external shape that can be inscribed within a circle with a diameter greater than or equal to 0.5 micrometers (μm) and less than or equal to 1.5 millimeters (mm).

[0068] The small lenses have a height measured in a direction perpendicular to the main surface on which they are arranged, which is greater than or equal to 0.1 μm and less than or equal to 50 μm.

[0069] The master surface can be defined as the surface including the center point of each microstructure, and can be a plane, sphere, spherical, or even a composite surface. This master surface can be a virtual surface when the microstructure is embedded in the lens, or it can be close to or identical to the physical outer surface of the ophthalmic lens when the microstructure is not embedded. The height of the microstructure can then be determined using a local axis perpendicular to this master surface, and the difference between the maximum positive deviation along this axis and the minimum negative deviation from the master surface can be calculated for each point of the microstructure.

[0070] Microlenses can have a periodic or pseudo-periodic layout, but they can also be randomly positioned. Exemplary layouts of microlenses can be grids with a constant grid step size, honeycomb layouts, multiple concentric rings, or continuous layouts, such as those with no space between microstructures.

[0071] These structures can provide light wavefront modification in terms of intensity, curvature, or optical deviation, wherein the intensity of the wavefront is configured such that the structure can be absorbent and can locally absorb wavefront intensity in the range of 0% to 100%, wherein the curvature is configured such that the structure can locally modify the wavefront curvature in the range of + / -20 diopters, and wherein the optical deviation is configured such that the structure can locally scatter light at an angle of + / -1° to + / -30°.

[0072] The distance between structures can range from 0 (continuous) to 3 times the distance between structures (separate microstructures).

[0073] In this specification, the terms “comprise” (and any of its grammatical variations, such as “comprises” and “comprising”), “have” (and any of its grammatical variations, such as “has” and “having”), “contain” (and any of its grammatical variations, such as “contains” and “containing”), and “include” (and any of its grammatical variations, such as “includes” and “including”) are open-ended connecting verbs. They are used to indicate the presence of a feature, whole, step, or component or group thereof, but do not exclude the presence or inclusion of one or more other features, wholes, steps, or components or groups thereof. Therefore, a method or a step in a method that “comprises,” “has,” “contains,” or “includes” one or more steps or elements possesses, but is not limited to, only possessing, those steps or elements.

[0074] Unless otherwise specified, all figures or expressions relating to quantities of ingredients, ranges, reaction conditions, etc., used herein should be understood to be modified in all cases by the term “about”. Similarly, unless otherwise specified, indications of a range of values ​​“from X to Y” or “between X and Y” according to the present invention mean that the values ​​of X and Y are included. Attached Figure Description

[0075] Figure 1 This is a schematic partial cross-sectional view of a composite mold according to a preferred embodiment of the present invention, wherein a thermosetting material fills the mold cavity;

[0076] Figures 2a-2e A schematic block diagram illustrating the steps of a method for obtaining an organic molded film by spin-coating a polymerization solution according to a first embodiment of the present invention is shown.

[0077] Figures 3a-3c A schematic block diagram illustrating the steps of a method for obtaining an organic molded film by spraying a polymerization solution according to another embodiment of the present invention is shown.

[0078] Figures 4a-4c A schematic block diagram illustrating the steps of a method for obtaining an organic molded film by dip-coating a polymerization solution according to another embodiment of the present invention is shown.

[0079] Figures 5a-5c A schematic block diagram illustrating the steps of a method for obtaining an organic molded film by microthermoforming under pressure, according to another embodiment of the present invention; and

[0080] Figures 6a-6c A schematic block diagram illustrating the steps of a method for obtaining an organic molded film by microthermoforming under vacuum, according to another embodiment of the present invention, is shown.

[0081] Figure 1 A composite mold 1 according to an exemplary embodiment of the present invention is illustrated in the figure. The composite mold specifically includes:

[0082] -A microstructured inorganic first outer mold component 2 (e.g., recessed and made of inorganic glass) on its first microstructured inner surface 2a.

[0083] - An inorganic second outer mold component 3 (e.g., a protruding part that is also made of inorganic glass) having a complementary and smooth second inner surface 3a.

[0084] - An organic molding film 4, configured to protect the microstructured inorganic first outer mold component 2 and conformally coated (with high replication fidelity) the first microstructured inner surface 2a, and

[0085] - A cavity 5 is defined between an organic molded film 4 and a second inner surface 3, and the cavity is configured to be filled with a cast thermosetting material 6, which is to be cast and then cured in the cavity 5 at a defined temperature for a certain duration.

[0086] As explained above, due to the excellent chemical and heat resistance selected for membrane 4, the applicant has determined that neither membrane 4 nor the first microstructured inner surface 2a below the inorganic first outer mold component 2 has been damaged.

[0087] After the curing of the cast thermosetting material 6 is completed, the resulting thermosetting product, such as a lens substrate configured to control myopia, is easily peeled off from the film 4, which itself is easily detached from the inorganic inner surface 2a.

[0088] As explained above, the thickness of the organic molding film 4 is preferably in the range of 1 / 10 to 1 / 100 of the average amplitude of the microstructured inner surface 2a of the inorganic first outer mold component 2, which allows the optical properties of the microstructure to be unaffected.

[0089] The organic molding membrane 4 is selected to be hydrophobic, preferably exhibiting a water contact angle greater than 120° at least on its microstructured inner surface designed to contact the thermosetting material 6 to be cast. The low surface tension of the membrane 4 allows for easy demolding of the cast and cured articles.

[0090] The membrane 4 was further selected to have a thickness between 10 nm and 500 μm, thereby enabling the high-fidelity replication of the original microstructure on the inorganic inner surface 2a.

[0091] In addition, the membrane 4 is selected to exhibit moderate adhesion to the inorganic first outer mold component 2 (e.g., inorganic glass) to maintain long production duration, thereby allowing easy detachment from the inorganic first outer mold component 2 for repair or cleaning.

[0092] As explained above, the membrane 4 preferably exhibits a moderate Young's modulus (between 100 MPa and 4000 MPa) to protect the inorganic first outer mold component 2 from impact.

[0093] exist Figures 2a-2e The schematic block diagram relates to an organic molded film 4 that can be applied as a polymerization solution by spin coating:

[0094] - Figure 2a The initial steps of depositing a polymeric solution 4a onto an inorganic microstructured inner surface 2a are shown (wherein the solution is based on at least one elastomer, thermoplastic polymer, or thermosetting polymer).

[0095] - Figure 2b The rotational unfolding of the deposition solution 4a is shown.

[0096] - Figure 2c A thin liquid precursor 4a is shown, forming a film 4 on the inorganic microstructured inner surface 2a, and...

[0097] - Figure 2d or Figure 2e This shows that it can be cured either by ultraviolet light or heat (see...). Figure 2d ), or by solvent evaporation (see Figure 2e Finally, membrane 4 is formed.

[0098] exist Figures 3a-3c The schematic block diagram relates to an organic molding film 4 that can be applied by spraying as a polymerization solution:

[0099] - Figure 3aThe initial steps of spraying a polymer solution 4a onto an inorganic microstructured inner surface 2a are shown (wherein the solution is based on at least one elastomer, thermoplastic polymer, and thermosetting polymer).

[0100] - Figure 3b This illustrates the subsequent formation of a precursor liquid film 4a on the inorganic microstructured inner surface 2a, and...

[0101] - Figure 3c The film 4 is shown to be ultimately formed by curing under heat or ultraviolet light.

[0102] exist Figures 4a-4c The schematic block diagram relates to an organic molded film 4 that can be applied by dip coating as a polymerization solution:

[0103] - Figure 4a The initial steps of immersing the inorganic first outer mold component 2 in the polymerization solution 4a are shown.

[0104] - Figure 4b This illustrates the formation of a precursor liquid film 4a on the inorganic microstructured inner surface 2a, and...

[0105] - Figure 4c The film 4 is shown to be ultimately formed by curing under heat or ultraviolet light.

[0106] exist Figures 5a-5c The schematic diagram relates to an organic molded film 4 that can be applied as a thin film via microthermoforming technology under pressure:

[0107] - Figure 5a The initial steps for assembling the precursor 4a of the thin film 4 are shown.

[0108] - Figure 5b The following steps are illustrated: applying air pressure P to bond the precursor 4a of the membrane 4 to the inorganic inner surface 2a of the first inorganic outer mold component 2a; and

[0109] - Figure 5c The final steps for forming a membrane 4 that is separably bonded to the inner surface 2a are shown.

[0110] exist Figures 6a-6c The schematic block diagram relates to an organic molded film 4 that can be applied as a thin film via vacuum through a microthermoforming technique:

[0111] - Figure 6a The initial steps for assembling the precursor 4a of membrane 4 are shown.

[0112] - Figure 6b The following steps are illustrated: applying a vacuum V to bond the precursor 4a of the membrane 4 to the inorganic inner surface 2a of the first inorganic outer mold component 2a; and

[0113] - Figure 6c The final steps for forming a membrane 4 that is separably bonded to the inner surface 2a are shown.

[0114] Examples of the composite mold and method of the present invention:

[0115] The following examples illustrate the invention in a more detailed but non-limiting manner.

[0116] Example 1: PDMS-based molded film applied by spin coating:

[0117] Based on the following characteristics, the two portions of PDMS according to Table 1 below will be used for membrane 4:

[0118] -PDMS: 184, from Dow Chemical;

[0119] - Preparation of the polymerization solution: Mix part A and part B PDMS at a ratio of 10:1 (wt:wt) and stir for 2 minutes, and then degas the mixture in a vacuum dryer (10-13 minutes) before use.

[0120] Table 1 :

[0121] characteristic unit result One or two parts two color colorless Viscosity (basic) Pa-second 5.1 Viscosity (mixture) Pa-second 3.5 thermal conductivity W / (m*°K) 0.27 Specific gravity (cured) 1.03 Curing time at 25℃ Hour 48 Thermosetting time at 100℃ minute 35 Thermosetting time at 125℃ minute 20 Thermosetting time at 150℃ minute 10 Shore A hardness tester 43

[0122] As referenced above Figures 2a-2d The PDMS film 4 is prepared by spin coating and then curing. Specifically, a PDMS mixture 4a is poured onto the microstructured inner surface 2a of the first inorganic glass outer mold component 2, which has been pre-treated with plasma, and then spin-coated thereon.

[0123] To achieve the desired film thickness between 1 μm and 100 μm, the spin coating (i.e., rotation) speed and duration were adjusted to reach the target thickness of the final cured film 4. By increasing the rotation speed, multiple films were obtained, each with a thickness between 10 and 100 μm, demonstrating excellent high-fidelity replication of the microstructure profile of the inorganic glass inner surface.

[0124] It can be noted that high fidelity replication of microstructure profiles can also be achieved by controlling PDMS viscosity, fine-tuning shrinkage rate and microstructure shape design, and / or by selectively curing PDMS using a mask and then washing away the uncured portions.

[0125] The PDMS precursor film is further cross-linked after being mixed with a curing agent, thus becoming a hydrophobic elastic film. Its modulus / hardness is adjusted by changing the degree of PDMS cross-linking. The Young's modulus of the PDMS film is controlled by changing the weight ratio of the curing agent, thereby altering the degree of PDMS cross-linking in the cured film.

[0126] It can be noted that, depending on the size of the PDMS polymer chain, the non-crosslinked PDMS can be almost a liquid or a semi-solid in the case of low or high numbers of repeating units.

[0127] Then, according to Figure 1 The principle is to cast a substance called... Ophthalmic lens substrates are manufactured by casting and curing in a mold cavity using homopolymers of diethylene glycol bis(allyl carbonate) and thermosetting lens substrates 6 of “MR7”, “MR8”, “1.74” (polyurethane thioester)).

[0128] The resulting lens substrate is easy to demold and has a replicated microstructure with high fidelity, while retaining the inner surface 2a of the first outer mold component 2 of the inorganic glass, because it is protected by the film 4 during the casting and curing steps, thus the film acts as a protective cover.

[0129] It should be noted that PDMS advantageously remains liquid at room temperature for many hours, even when mixed with a crosslinking agent, and PDMS can flow into microstructures at high resolution, also providing precise control over film thickness. Therefore, with some optimization, it should be possible to flow into microstructures of several nanometers in size. The resulting original microstructures thus exhibit easy and satisfactory moldability.

[0130] It should also be noted that after plasma treatment of this inorganic glass, the PDMS film is easily bonded to the inorganic glass of the first molding part 2, and due to its low surface tension, it provides excellent demolding properties.

[0131] It should be further noted that PDMS is particularly advantageous because it exhibits excellent chemical resistance to many solvents, such as, but not limited to, methanol, glycerol, propanol, acetone and pyridine.

[0132] Example 2: Molded film based on polyurethane rubber applied by spin coating:

[0133] -Raw materials: Polyurethane liquid rubber Clear 30, from Smooth-On.

[0134] - Preparation of the polymerization solution: First, Clear... Mix parts A and B of 30 at a 1:1 (volume / volume) ratio, stir for 3 minutes, and then degas.

[0135] By dropping the polymer solution thus prepared onto the first outer mold component 2 of the inorganic glass and referring to the above... Figures 2a-2c Polyurethane rubber film 4 was prepared by spin coating as disclosed, to form a thin layer between 10 μm and 100 μm, depending on the spin coater's rotation speed. The glass insert thus prepared was placed in an oven to be dried according to… Figure 2d Curing the polyurethane thin precursor layer 4a yields membrane 4.

[0136] Example 3: Thiol-olefin-based thermosetting molded film applied by spin coating:

[0137] - Raw material: "NOA 61", from Norland Products, is a transparent, colorless, liquid, one-component photopolymer adhesive that cures upon exposure to ultraviolet light (see its detailed properties in Table 3 below).

[0138] When fully cured, "NOA 61" exhibits excellent adhesion and solvent resistance. After aging at 50°C for 12 hours, followed by UV curing, "NOA 61" can withstand temperatures ranging from -150°C to 125°C.

[0139] Table 2 :

[0140] solid 100％ Viscosity at 25°C 300cp Refractive index of cured polymer 1.56 Elongation at break 38％ Elastic modulus (psi) 150,000 Tensile strength (psi) 3,000 Hardness - Shore D 85

[0141] - Application and curing of the polymerization solution: Figures 2a-2d The steps are as follows.

[0142] "NOA 61" was spin-coated at 4000 rpm for 30 seconds, resulting in a final thickness of 60 μm.

[0143] Then, at an average strength of 48 mW / cm 2 High-wattage UV lamp (400W) At 5000 EC, the spin-coating solution was cured with ultraviolet light within 10 minutes.

[0144] The cured film 4 was stabilized at 60°C for 15 hours.

[0145] Example 4: Molded film based on fluoropolymer applied by spin coating :

[0146] - Raw materials: THV 220G, from 3M.

[0147] - Preparation of polymerization solution: Dissolve THV 220G in acetone.

[0148] By dropping the polymer solution thus prepared onto the first outer mold component 2 of the inorganic glass and referring to the above... Figures 2a-2c The fluoropolymer membrane 4 is prepared by spin coating as disclosed, in order to form a thin precursor layer of membrane 4.

[0149] according to Figure 2e The solvent evaporation step involves evaporating acetone during spin coating to form a thin layer of THV 220G on the first outer mold component 2 of inorganic glass, with the final thickness of the film 4 being between 10 μm and 100 μm.

[0150] Example 5: TPU-based molded film applied via microthermoforming :

[0151] -Raw materials:

[0152] A4000 is an aliphatic thermoplastic polyurethane (TPU) from Covestro.

[0153] - Application of TPU-based precursor layers:

[0154] A thin A4000-based precursor layer was heated to its softening point of 110°C, and then according to... Figures 5a-5c Each precursor laminator is pressed against the first outer mold component 2 of the inorganic glass using pressurized nitrogen gas, and / or according to... Figures 6a-6c Each precursor layer is pulled against this inorganic mold component 2 by vacuum so as to deform against the microstructure contour 2a on the inorganic mold component 2.

[0155] Each TPU-based membrane 4 achieves a final thickness between 1 μm and 100 μm.

[0156] Example 6: PDMS-based molded film applied by spray coating :

[0157] -Raw materials: 184, from Dow Corning.

[0158] -Preparation of polymerization solution: 184 is too viscous and cannot be used as is. Dilute it with several solvents, such as hexane, silicone fluid, or Dow Corning "200 fluid". 184.

[0159] according to Figures 3a-3c The spray gun with a medium nozzle is held above the first outer mold part 2 of inorganic glass, and PDMS solution droplets are sprayed under compressed nitrogen gas.

[0160] Alternatively, the first outer mold component 2 of the inorganic glass is rotated during spraying to achieve a more uniform thickness. This forms a PDMS liquid film 4a, the thickness of which is specifically controlled by the spraying duration, pressure, and rotation speed of the mold component 2.

[0161] The PDMS liquid film 4a is then cured under heat and / or ultraviolet light to obtain a film 4 with a final thickness between 1 μm and 100 μm.

[0162] Example 7: PDMS-based molded film applied by dip coating :

[0163] - Raw materials: Hydroxyl-terminated PDMS (Mw = 18000 g mol)-1 ), from Sigma Aldrich.

[0164] Preparation of the polymerization solution: The PDMS-OH was dissolved in n-heptane, and then the crosslinking agent (TEOS) and 0.2 wt% dibutyltin dilaurate catalyst were added to the polymerization solution. The polymerization mixture was stirred at room temperature for 30 minutes and then degassed under vacuum.

[0165] according to Figures 4a-4c The inorganic glass first outer mold component 2 is immersed in this PDMS-OH solution and then removed, and this process is repeated for several cycles until a liquid precursor film 4a of the required thickness is formed.

[0166] After curing this liquid film 4a under heat and / or ultraviolet light, a solid hydrophobic film 4 is obtained, with a final thickness between 1 μm and 100 μm.

[0167] Example 8: Hydrophobic surface treatment of polymer-molded films :

[0168] -Raw materials: Ease 200, from Smooth-On.

[0169] - Further use Ease 200 spray coating is applied to each of the above films 4 on the first outer mold component 2 of inorganic glass according to Examples 1-7 above, in order to achieve better hydrophobicity (proven by a higher contact angle), thereby improving the demolding of thermosetting optical products after casting and curing.

[0170] Therefore, this release agent is particularly suitable for spraying onto fluoropolymers, but it can also be sprayed onto reactive polysiloxanes, PVA (polyvinyl alcohol), waxes and silicone oils in a non-limiting manner.

[0171] It should be noted that this hydrophobic surface treatment method can also be applied to hydrophilic or less hydrophobic films using another coating technique, such as spin coating or dip coating, to obtain the desired hydrophobic molded film.

Claims

1. A composite mold (1) for manufacturing thermosetting optical articles, manufactured by casting a thermosetting material (6) into a mold cavity (5), the thermosetting optical articles being usable as ophthalmic lens substrates and including a microstructured main surface, the composite mold (1) comprising: - An inorganic first external mold component (2), the inorganic first external mold component having a first inner surface (2a), and - An organic molding film (4), which is separably bonded to the first inner surface (2a) and has a microstructured pattern, the microstructured pattern being configured to form the microstructured main surface directly after the thermosetting material (6) is cast in contact with the organic molding film (4), while maintaining the pattern of the microstructure designed in the composite mold. The organic molded film (4) is hydrophobic at least on the microstructured pattern and has a thickness between 10 nm and 500 μm.

2. The composite mold (1) according to claim 1, wherein, The organic molded film (4): - Exhibits a water contact angle greater than 100° at least on the microstructured pattern, and / or - Thickness is between 1 μm and 100 μm.

3. The composite mold (1) according to claim 2, wherein, The organic molded film (4): - At least on the microstructured pattern, it exhibits a water contact angle greater than 110°.

4. The composite mold (1) according to claim 2, wherein, The organic molded film (4): - At least on the microstructured pattern, it exhibits a water contact angle greater than 120°.

5. The composite mold (1) according to claim 1, wherein, The organic molded film (4) is based on at least one polymer selected from elastomers, thermoplastic polymers, and thermosetting polymers. Furthermore, the organic molded film (4) is of the single-layer or multi-layer type and is hydrophobic on the microstructured pattern.

6. The composite mold (1) according to claim 2, wherein, The organic molded film (4) is based on at least one polymer selected from elastomers, thermoplastic polymers, and thermosetting polymers. Furthermore, the organic molded film (4) is of the single-layer or multi-layer type and is hydrophobic on the microstructured pattern.

7. The composite mold (1) according to claim 3, wherein, The organic molded film (4) is based on at least one polymer selected from elastomers, thermoplastic polymers, and thermosetting polymers. Furthermore, the organic molded film (4) is of the single-layer or multi-layer type and is hydrophobic on the microstructured pattern.

8. The composite mold (1) according to claim 4, wherein, The organic molded film (4) is based on at least one polymer selected from elastomers, thermoplastic polymers, and thermosetting polymers. Furthermore, the organic molded film (4) is of the single-layer or multi-layer type and is hydrophobic on the microstructured pattern.

9. The composite mold (1) according to claim 5, wherein, The organic molded film (4) has a Young's modulus between 100 MPa and 4000 MPa as measured according to ASTM D882-12.

10. The composite mold (1) according to claim 6, wherein, The organic molded film (4) has a Young's modulus between 100 MPa and 4000 MPa as measured according to ASTM D882-12.

11. The composite mold (1) according to claim 7, wherein, The organic molded film (4) has a Young's modulus between 100 MPa and 4000 MPa as measured according to ASTM D882-12.

12. The composite mold (1) according to claim 8, wherein, The organic molded film (4) has a Young's modulus between 100 MPa and 4000 MPa as measured according to ASTM D882-12.

13. The composite mold (1) according to claim 5, wherein, The organic molded film (4) is hydrophobic over its entire thickness.

14. The composite mold (1) according to claim 6, wherein, The organic molded film (4) is hydrophobic over its entire thickness.

15. The composite mold (1) according to claim 7, wherein, The organic molded film (4) is hydrophobic over its entire thickness.

16. The composite mold (1) according to claim 8, wherein, The organic molded film (4) is hydrophobic over its entire thickness.

17. The composite mold (1) according to any one of claims 5 to 16, wherein, The organic molded film (4) is based on at least one cross-linked elastomer.

18. The composite mold (1) according to claim 17, wherein, The at least one crosslinked elastomer is selected from silicone rubber and polyurethane rubber.

19. The composite mold (1) according to claim 18, wherein, The silicone rubber is a two-component polydimethylsiloxane (PDMS).

20. The composite mold (1) according to claim 18, wherein, The polyurethane rubber is a two-component liquid urethane rubber.

21. The composite mold (1) according to any one of claims 5 to 16, wherein, The organic molded film (4) is based on at least one thermosetting polymer.

22. The composite mold (1) according to claim 21, wherein, The at least one thermosetting polymer is selected from thiol-olefin thermosetting materials and thermosetting polyurethanes.

23. The composite mold (1) according to claim 22, wherein, The thiol-olefin thermosetting material is a one-component liquid photopolymer adhesive.

24. The composite mold (1) according to any one of claims 5 to 16, wherein, The organic molded film (4) is based on at least one thermoplastic polymer.

25. The composite mold (1) according to claim 24, wherein, The at least one thermoplastic polymer is selected from fluorinated polymers and thermoplastic polyurethane (TPU).

26. The composite mold (1) according to claim 25, wherein, The fluorinated polymer is a terpolymer of tetrafluoroethylene, hexafluoropropylene, and vinylidene fluoride.

27. The composite mold (1) according to any one of claims 1 to 16, 18 to 20, 22 to 23 and 25 to 26, wherein, The inorganic first external mold component (2) has a first inner surface (2a) including a microstructure, and the first side of the organic molding film (4) is separably bonded to the microstructure without adhesive between them. The organic molding film (4) adheres to the microstructure on the first surface and has an opposite second side forming the microstructured pattern. The composite mold (1) further includes an inorganic second outer mold component (3), which has a second inner surface (3a) opposite to the first inner surface (2a), and the mold cavity (5) is defined between the organic molding film (4) and the second inner surface (3a).

28. The composite mold (1) according to claim 27, wherein, The inorganic first outer mold component (2) is made of inorganic glass.

29. The composite mold (1) according to claim 27, wherein, The first inner surface (2a) of the inorganic first outer mold component (2) has a recessed first inner surface (2a), and wherein the thickness of the organic molding film (4) is in the range of 1 / 10 to 1 / 100 of the average amplitude of the microstructure of the inorganic first outer mold component (2).

30. The composite mold (1) according to claim 28, wherein, The first inner surface (2a) of the inorganic first outer mold component (2) has a recessed first inner surface (2a), and wherein the thickness of the organic molding film (4) is in the range of 1 / 10 to 1 / 100 of the average amplitude of the microstructure of the inorganic first outer mold component (2).

31. A method for manufacturing a thermosetting optical article, said thermosetting optical article being usable as an ophthalmic lens substrate and comprising a microstructured main surface, wherein, The method includes: a) Thermosetting material (6) is cast into the cavity (5) of the composite mold (1) according to any one of the preceding claims, such that the thermosetting material (6) contacts the organic molding film (4) and the second inner surface (3a) of the inorganic second outer mold component (3) opposite to the first inner surface (2a), but does not contact the first inner surface (2a). b) Curing the thermosetting material (6) cast into the mold cavity (5); and c) Demolding the molded thermosetting material obtained in step b) includes peeling the molded thermosetting material from the organic molding film (4) so ​​that the microstructured pattern of the organic molding film (4) directly forms the microstructured main surface of the obtained thermosetting optical article, while maintaining the pattern of the microstructure designed in the composite mold.

32. The method according to claim 31, wherein, The microstructured main surface is configured to control myopia.

33. The method according to claim 31, wherein, The organic molded film (4) resists erosion from the thermosetting material (6) during casting step a), which is selected from: - Cyclic olefin copolymers, - Homopolymers and copolymers of allyl carbonates of linear or branched aliphatic or aromatic polyols. - Homopolymers and copolymers of (meth)acrylic acid and its esters, - Homopolymers and copolymers of thio(meth)acrylic acid and its esters, - Homopolymers and copolymers of allyl esters and allyl aromatic compounds, - A copolymer of carbamate and thiocarbamate, - Homopolymers and copolymers of epoxy resins, and - Homopolymers and copolymers of sulfides, disulfides and cyclic sulfides.

34. The method according to claim 33, wherein, The cyclic olefin copolymer is an ethylene / norbornene or an ethylene / cyclopentadiene copolymer.

35. The method according to claim 33, wherein, The homopolymers and copolymers of the linear or branched aliphatic or aromatic polyols of allyl carbonate are homopolymers of diethylene glycol bis(allyl carbonate).

36. The method according to claim 33, wherein, The homopolymers and copolymers of (meth)acrylic acid and its esters are derived from bisphenol A.

37. The method according to claim 33, wherein, The allyl ester is derived from bisphenol A or phthalic acid.

38. The method according to claim 33, wherein, The allyl aromatic compound is styrene.

39. A method for obtaining the composite mold (1) according to any one of claims 1 to 30, wherein, The method includes: A) Provides a polymer composition that is hydrophobic or coated with a hydrophobic surface layer and capable of forming an organic molding film (4) that can be separably bonded to the inorganic first outer mold component (2), the polymer composition being resistant to erosion from the thermosetting material (6) to be cast. B) Apply the polymer composition to the first inner surface (2a) of the inorganic first outer mold component (2) to form the precursor layer (4a) of the organic molding film (4), and C) The applied precursor layer (4a) is treated to form the organic molded film (4), the organic molded film having a thickness between 10 nm and 500 μm and surface tension that allows it to be peeled from the cast and cured thermosetting optical article while maintaining the pattern of the microstructure designed in the composite mold.

40. The method according to claim 39, wherein, The first inner surface (2a) of the inorganic first outer mold component (2) is formed of inorganic glass and includes a microstructure, to which the organic molding film (4) is bonded in fit and fit in steps B) and C) to form the microstructured pattern.

41. The method according to claim 40, wherein, The polymer composition comprises a solution containing a solvent and at least one polymer selected from elastomers, thermoplastic polymers and thermosetting polymers, and wherein step B) comprises coating the solution onto the first inner surface (2a) of the inorganic first outer mold component (2).

42. The method of claim 41, wherein step B) comprises coating the solution onto the first inner surface (2a) of the inorganic first outer mold component (2) by spin coating, spray coating or dip coating.

43. The method according to claim 41, wherein, Step C) includes: - Crosslink the precursor layer (4a), or - Evaporate the solvent.

44. The method according to claim 43, wherein, The precursor layer (4a) is crosslinked under heat and / or ultraviolet radiation.

45. The method according to claim 43, wherein, The precursor layer (4a) is crosslinked under heat and / or ultraviolet radiation in the presence of at least one polymer selected from elastomers and thermosetting polymers.

46. ​​The method according to claim 43, wherein, The solvent is evaporated in the case of spin coating in step B), where at least one polymer is selected from thermoplastic polymers.

47. The method of claim 40, wherein, In the case that the polymer composition is solvent-free, steps B) and C) include microthermoforming the polymer composition by compressing the microstructure of the first inner surface (2a) of the first inorganic outer mold component (2) using pressure and / or vacuum.

48. The method of claim 40, wherein, When the polymer composition is solvent-free and when the at least one polymer is selected from thermoplastic polymers, steps B) and C) include microthermoforming the polymer composition by compressing the microstructure of the first inner surface (2a) of the first inorganic outer mold component (2) using pressure and / or vacuum.

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