A surface composite layer for optical mold rollers and its preparation method

Abstract

This invention relates to mold manufacturing technology in the optical film industry, and more particularly to a surface composite layer for optical mold rollers and its preparation method. The optical mold roller includes a metal roller core, a buffer layer, and a UV-curable resin working layer with a microstructure on its surface. The preparation method of the surface composite layer includes: forming a diamond-like protective layer with a thickness of 10 nm to 200 nm on the microstructure surface of the resin working layer by low-temperature plasma-enhanced chemical vapor deposition; then forming a fluorinated silane self-assembled monolayer anti-adhesion layer with a thickness of 1 nm to 5 nm on the surface of the protective layer by vapor-phase self-assembly, wherein the fluorinated silane is chemically bonded to the protective layer through siloxane covalent bonds. The protective layer physically blocks the penetration of organic solvent molecules, and the anti-adhesion layer reduces the interfacial adhesion between the cured resin and the mold surface. This invention effectively solves the problems of solvent corrosion and difficult demolding when replicating the microstructure of homologous UV-curable resin in resin-based optical mold rollers, significantly extending the service life of the mold roller.

Description

Technical Field

[0001] This invention relates to the field of novel optical film industry, and more particularly to the field of optical mold manufacturing, specifically to a surface composite layer for optical mold rollers and its preparation method. Background Technology

[0002] Optical mold rollers are core tooling for manufacturing optical products such as optical films, light guides, and brightness enhancement films. In recent years, with the development of ultraviolet nanoimprint lithography technology, the feasibility of using resin materials to replace traditional metal materials in the manufacture of optical mold rollers has become apparent. Resin-based mold rollers offer advantages such as high molding efficiency, low replication cost, and rapid mass production, and are increasingly widely used in the manufacturing of optical products such as prism films and microstructured anti-reflective films.

[0003] However, resin-based optical mold rollers face a series of unique failure problems during use. Unlike metal molds, the surface microstructure of resin molds is composed of UV-curable resin. When the mold roller is used for continuous imprinting to prepare optical films, the microstructure on the mold surface needs to repeatedly come into contact with liquid UV-curable resin and be cured and demolded. During this process, the active diluents, organic monomers, and other components contained in the liquid UV-curable resin belong to the same organic polymer material system as the mold resin matrix. According to the principle of "like dissolves like," these small molecule components easily penetrate into the resin cross-linking network on the mold surface, causing the microstructure to swell and deform, thus affecting the structural accuracy and optical performance of the optical film product. At the same time, the cured resin and the mold resin generate strong interfacial bonding forces at the interface due to the mutual diffusion and entanglement of molecular chains. This chemical adhesion force far exceeds conventional physical adhesion, leading to difficulties in demolding, resin residue, and even damage to the mold microstructure.

[0004] To address the issues of mold surface protection and demolding, various technical solutions have been proposed in this field.

[0005] In the field of metal mold protection, CN 102433562 A proposes a mold for processing optical films, which includes a mold substrate, an alumina thin film formed on the surface of the substrate by atomic layer deposition (ALD), and a fluorinated self-assembled monomolecular film layer formed on the surface of the alumina thin film. In this scheme, the alumina thin film, as a high-hardness film, provides physical protection for the mold substrate, while the fluorinated self-assembled monomolecular film layer improves demolding performance by reducing surface energy. The technical effect is summarized as the mold having the characteristic of easy demolding.

[0006] In terms of anti-sticking and release, fluorinated silane self-assembled monolayers have been used for surface modification of nanoimprint dies. US 20060012079 A1 discloses a release layer for dies in nanoimprint lithography, which forms a self-assembled monolayer of organosilane release agent on the die surface through self-assembly to assist in release during the imprinting process. In the field of organosilicon dies, CN 101795839 A discloses an organosilicon die containing a release coating of fluorinated silane compound on an oxidized patterned surface. This release coating is covalently bonded to the oxidized organosilicon surface through siloxane bonds, enabling the replication of an organosilicon die from an organosilicon die. Furthermore, CN 105018928 A discloses a nanosurface coating method for irregularly shaped metal surfaces, which uses atomic layer vapor deposition to form an oxide film on the metal surface, and then uses this oxide film as an adhesive layer to deposit an oxysilane-based fluorocarbon film layer.

[0007] However, the aforementioned existing technologies all have several shortcomings. For example, the alumina thin film and fluorinated self-assembled monolayer scheme proposed in CN 102433562 A, and the scheme disclosed in CN 105018928 A, are both applied to metal molds. The design of these schemes is based on physical protection and physical demolding of rigid substrates, without considering the chemical corrosion problem caused by organic solvent penetration in resin-based molds. When the above schemes are directly applied to resin-based molds, their applicability and effectiveness are still unclear because the thermal stability, surface chemical properties, and mechanical properties of resin substrates are fundamentally different from those of metal and inorganic substrates.

[0008] Regarding the construction of fluorinated anti-stick layers, CN 102433562 A describes a fluorinated component that chemically bonds to the active sites on the alumina surface via carboxyl groups, while CN 101795839 B describes a scheme where fluorinated silanes are covalently bonded to the oxidized organosilicon surface via siloxane bonds. These two chemical bonding methods differ significantly in bond energy and chemical resistance. However, existing technologies have not differentiated or studied the applicability of different chemical bonding methods for long-term use of resin-based optical molds in environments containing organic solvents. The release layer scheme disclosed in US 20060012079 A1 is mainly used for release aids in nanoimprinting processes and similarly does not address the protection of resin-based molds under long-term contact with organic solvents.

[0009] More fundamentally, none of the aforementioned existing technologies have recognized the unique challenges faced by resin-based optical molds in replicating the microstructure of homologous UV-curable resins. These challenges include the penetration and corrosion of the mold resin matrix by organic components in the liquid UV-curable resin, and the chemical adhesion at the curing interface caused by molecular chain entanglement. Existing technologies have consistently focused on physical properties such as hardness, wear resistance, and demolding performance, failing to recognize that when both the mold and product materials are organic polymer systems, chemical interactions are the key factor leading to mold failure. This failure mode does not exist in metal or inorganic molds. Therefore, the various surface treatment solutions developed for metal and inorganic molds are neither specifically designed to address this failure mechanism nor easily transferred directly to resin-based molds to achieve satisfactory long-term performance.

[0010] Based on this, how to provide a surface protection solution that can simultaneously resist organic solvent penetration and corrosion and inhibit the adhesion of interfacial molecular chains, for the special working conditions of resin-based optical mold rollers when replicating microstructures of homologous UV-curable resins, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to provide a surface composite layer for optical mold rollers and a method for preparing the same, so as to reduce or avoid the problems mentioned above.

[0012] To address the aforementioned technical problems, this invention proposes a method for preparing a surface composite layer for an optical mold roller. The optical mold roller includes a metal roller core, a buffer layer disposed on the outer surface of the metal roller core, and a working layer disposed on the outer surface of the buffer layer. The working layer has a microstructure on its surface, and the surface composite layer is formed on the surface of the microstructure. The method for preparing the surface composite layer for the optical mold roller includes the following steps: Step 1, placing the optical mold roller in a plasma treatment chamber and treating it with a radio frequency power of 100W for 5 minutes in an oxygen atmosphere to clean the surface of the microstructure and introduce a first active functional group onto the surface of the microstructure; Step 2, placing the optical mold roller treated in Step 1 in a plasma-enhanced chemical vapor deposition chamber, using hydrocarbons as the carbon source gas and argon as the discharge gas, and depositing a diamond-like carbon protective layer under conditions of radio frequency power of 100W to 300W and deposition temperature not exceeding 200℃. The deposition time is 10 to 60 minutes, and the thickness of the diamond-like carbon protective layer is 10 nm to 200 nm. Step three: The optical mold roller with the deposited diamond-like carbon protective layer is placed in a plasma treatment chamber and treated with 80 W of radio frequency power for 3 minutes in an oxygen atmosphere, introducing a second active functional group onto the surface of the diamond-like carbon protective layer. Step four: The optical mold roller treated in step three is placed in a vacuum self-assembly chamber. Using fluorinated silane as a precursor, the fluorinated silane is heated to 100°C to 130°C to evaporate into vapor. The temperature of the optical mold roller is controlled at 50°C to 100°C, and the vacuum degree of the chamber is controlled at 0.005 bar to 0.05 bar. Vapor phase self-assembly is performed for 30 to 120 minutes. The fluorinated silane is chemically bonded to the surface of the diamond-like carbon protective layer through siloxane covalent bonds, forming a self-assembled monolayer anti-adhesion layer with a thickness of 1 nm to 5 nm.

[0013] Preferably, the hydrocarbon is selected from any one of methane, acetylene, or benzene.

[0014] Preferably, the deposition temperature in step two is 25°C to 150°C.

[0015] Preferably, the fluorinated silane in step four is selected from any one of 1H,1H,2H,2H-perfluorodecyltrichlorosilane, 1H,1H,2H,2H-perfluorooctyltrichlorosilane, or tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane.

[0016] Preferably, the first and second active functional groups are oxygen-containing active functional groups.

[0017] The present invention also proposes a surface composite layer for optical mold rollers prepared according to the above method, comprising: a protective layer, wherein the material of the protective layer is diamond-like carbon and the thickness of the protective layer is 10 nm to 200 nm; and an anti-adhesion layer, wherein the anti-adhesion layer is disposed on the outer surface of the protective layer, the material of the anti-adhesion layer is fluorinated silane, wherein the fluorinated silane is chemically bonded to the surface of the protective layer through siloxane covalent bonds, the anti-adhesion layer is a self-assembled monolayer, and the thickness of the anti-adhesion layer is 1 nm to 5 nm.

[0018] Preferably, the fluorinated silane is selected from any one of 1H,1H,2H,2H-perfluorodecyltrichlorosilane, 1H,1H,2H,2H-perfluorooctyltrichlorosilane, or tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane.

[0019] Preferably, the thickness of the protective layer is 25 nm to 100 nm, and the thickness of the anti-adhesion layer is 1.5 nm to 3 nm.

[0020] Preferably, the deposition temperature of the diamond-like protective layer is not higher than 200°C.

[0021] This invention effectively solves two core problems faced by resin-based optical mold rollers in replicating the microstructures of homologous UV-cured resins: organic solvent penetration corrosion and interfacial chemical adhesion, through the synergistic combination of a diamond-like carbon (DLC) protective layer and a fluorinated silane anti-adhesion layer. The protective layer, with its dense DLC structure, physically blocks the penetration pathways of organic solvent molecules, protecting the resin microstructure from swelling, deformation, and chemical erosion. The anti-adhesion layer utilizes the ultra-low surface energy of the fluorinated silane and the chemical repulsion effect of the perfluorinated alkyl chains to significantly reduce the interfacial adhesion between the cured resin and the mold surface, inhibiting molecular chain entanglement at the interface and achieving clean demolding. The two layers are chemically bonded together by siloxane covalent bonds, giving the surface composite layer excellent long-term stability in organic solvent environments. The entire preparation process employs low-temperature plasma-enhanced chemical vapor deposition and vapor-phase self-assembly, with a process temperature not exceeding 200℃, making it fully applicable to resin-based mold materials and capable of achieving uniform and conformal full coverage on complex microstructure surfaces. Attached Figure Description

[0022] The accompanying drawings are intended only to illustrate and explain this application and do not limit the scope of the invention.

[0023] Figure 1 The diagram shown is a structural schematic of an optical mold roller according to a specific embodiment of the present invention. Detailed Implementation

[0024] To provide a clearer understanding of the technical features, objectives, and effects of the present invention, the specific embodiments of the present invention will now be described in detail.

[0025] Figure 1 A schematic diagram of an optical mold roller according to a specific embodiment of the present invention is shown. For clarity, the optical mold roller has been partially enlarged in the figure to show the surface composite layer structure of the optical mold roller of the present invention. Figure 1 As shown, the optical mold roller generally has a cylindrical roller structure, which includes, from the inside out, a metal roller core 1, a buffer layer 2, a working layer 3, and the surface composite layer 45 of the present invention. The surface composite layer 45 further includes a protective layer 4 disposed on the outer surface of the working layer 3 and an anti-adhesion layer 5 disposed on the outer surface of the protective layer 4. The protective layer 4 and the anti-adhesion layer 5 together constitute the surface composite layer 45 of the present invention.

[0026] The metal roller core 1, serving as the structural support core of the die roller, is typically made of steel, and its outer surface is precision-machined to achieve the required cylindricity and surface roughness. The metal roller core 1 provides mechanical support for the entire die roller, ensuring sufficient rigidity and dimensional stability during the imprinting process.

[0027] A buffer layer 2 is disposed on the outer surface of the metal roller core 1. Its function is to buffer and absorb the stress generated during the imprinting process, while providing a good adhesion substrate for the upper working layer. The buffer layer 2 can be coated onto the surface of the metal roller core 1 by a combination of primer treatment and precision slot coating. It can be a UV-curable flexible resin, such as a flexible UV resin of polyurethane acrylate or a difunctional polyurethane acrylate resin. This type of resin has both excellent flexibility and excellent cohesion. After curing, the coating can still maintain structural stability under bending and external force.

[0028] The working layer 3 is disposed on the outer surface of the buffer layer 2, and its surface is formed with a raised and recessed pattern for replicating optical microstructures. This working layer 3 can be made of a high-modulus UV-curable resin, filled with nanoparticles to improve its elastic modulus and resistance to deformation. The raised and recessed pattern on the surface of the working layer 3 is obtained through a roll-to-roll UV embossing process, i.e., a metal master roller (not shown in the figure) with a microstructure pattern on its surface is rolled against a metal roller core 1 coated with liquid UV resin. In a constant gap mode, the liquid resin fills the microstructure on the surface of the metal master roller. After UV curing, a working layer 3 with a complementary pattern is formed on the surface of the buffer layer 2 of the metal roller core 1. Depending on the optical film product to be replicated, the microstructure pattern can be selected from prism structures, moth-eye structures, microlens array structures, or other micro / nano structures with optical functional characteristics. The microstructure on the surface of the metal master roller can be raised or recessed, and the pattern on the surface of the working layer 3 is correspondingly a complementary recessed or raised pattern.

[0029] As mentioned above, the protective layer 4 and the anti-adhesion layer 5 together constitute the surface composite layer 45 of the present invention.

[0030] The protective layer 4 is disposed on the outer surface of the working layer 3 and is formed on the microstructure surface of the working layer 3 by a low-temperature plasma-enhanced chemical vapor deposition process. The material of the protective layer 4 is selected from diamond-like carbon, and its density is sufficient to block the penetration of organic solvent molecules in the liquid UV adhesive, thereby preventing the resin matrix of the working layer 3 from swelling, deformation and chemical corrosion during use.

[0031] An anti-adhesion layer 5 is disposed on the outer surface of the protective layer 4. It is formed by the self-assembly of fluorinated silane molecules on the surface of the protective layer 4 to form a monolayer, and is chemically bonded to the surface of the protective layer 4 through siloxane covalent bonds. This anti-adhesion layer 5 has ultra-low surface energy, effectively reducing the adhesion between the cured resin and the mold surface during the imprinting process. Simultaneously, its fluorocarbon chains chemically repel the polar monomers in the liquid UV adhesive, further inhibiting molecular chain entanglement at the interface. The protective layer 4 and the anti-adhesion layer 5 work synergistically to constitute a surface protection system for the resin-based mold roller working layer 3.

[0032] The aforementioned metal roller core 1, buffer layer 2, and working layer 3 together constitute the main body structure of the optical mold roller. As mentioned earlier, this main body structure achieves rapid mass production through a one-time precision machining of the metal master roller combined with a roller-to-roll UV embossing replication process. Based on this, the surface composite layer 45 provided by this invention (i.e., the combination of protective layer 4 and anti-adhesion layer 5) solves the two core problems of organic solvent penetration corrosion and interfacial chemical adhesion faced by this resin-based mold roller during long-term use.

[0033] The surface composite layer and its preparation method provided by the present invention will be described in detail below with reference to specific embodiments.

[0034] As described above, the protective layer 4 is disposed on the outer surface of the working layer 3, and is formed on the microstructure surface of the working layer 3 by a low-temperature plasma-enhanced chemical vapor deposition process. The material of the protective layer 4 is selected from diamond-like carbon. The thickness of the protective layer 4 is 10 nm to 200 nm, preferably 20 nm to 100 nm.

[0035] Low-temperature plasma-enhanced chemical vapor deposition (PECVD) utilizes the energy of plasma to drive a chemical reaction, enabling the deposition process to occur at temperatures far lower than those of conventional PECVD. The deposition temperature is no higher than 200°C, preferably between room temperature and 150°C. Using hydrocarbons as the carbon source gas and argon or hydrogen as the carrier gas, under radio frequency (RF) or microwave plasma excitation, the carbon source gas dissociates into carbon-containing active groups, which are then deposited on the microstructure surface of the working layer 3 to form a diamond-like carbon film. The hydrocarbons are preferably methane, acetylene, or benzene. By adjusting process parameters such as RF power, reaction gas pressure, gas flow ratio, and deposition time, the thickness, sp³ / sp² hybridization ratio, and internal stress of the protective layer 4 can be controlled. The deposition temperature can be further preferably controlled within the range of 25°C to 100°C to accommodate resin-based working layers 3 with different thermal stability requirements.

[0036] The protective layer 4 has extremely high density, effectively blocking the penetration pathways of organic solvent molecules in the liquid UV adhesive and preventing small organic molecules from seeping in through the molecular network gaps of the resin matrix in the working layer 3. This avoids swelling, deformation, and chemical corrosion of the working layer 3 during use. The density of the protective layer 4, characterized by water vapor transmission rate, is no higher than 10⁻² g·m⁻²·day⁻¹, preferably no higher than 10⁻¹. 5 g·m⁻²·day⁻¹. Furthermore, diamond-like materials possess similar high hardness and low coefficient of friction to diamond, providing mechanical protection for the resin microstructure of the working layer 3 and reducing microstructure wear caused by repeated contact and friction during the imprinting process.

[0037] While fulfilling its physical barrier function, the protective layer 4 also needs to provide active sites for the subsequent chemical grafting of fluorinated silanes. The diamond-like carbon (DLC) layer itself is chemically inert and lacks sufficient active functional groups on its surface. Therefore, after depositing the DLC protective layer 4, its surface is treated with oxygen plasma or ultraviolet ozone to introduce oxygen-containing functional groups, including hydroxyl and carboxyl groups. These functional groups serve as anchoring sites for the chemical bonding of fluorinated silane molecules.

[0038] An anti-adhesion layer 5 is disposed on the outer surface of the protective layer 4, and is obtained by self-assembling a fluorinated silane monolayer on the surface of the protective layer 4. The material of the anti-adhesion layer 5 is a fluorinated silane, preferably 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS, molecular formula CF3-(CF2)7-(CH2)2-SiCl3). In addition, the material of the anti-adhesion layer 5 can also be selected from other long-chain fluorinated alkyl silanes, such as 1H,1H,2H,2H-perfluorooctyltrichlorosilane (FOTS), tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane (F13-TCS), etc. One end of the above-mentioned fluorinated silane molecule is a trichlorosilane group (-SiCl3), and the other end is a long chain of perfluorinated alkyl (such as -CF2-CF2-CF3), with an ethylene linking chain (-(CH2)2-) connecting the silane group and the fluorinated alkyl chain in the middle.

[0039] Fluorosilane molecules form a monolayer on the surface of protective layer 4 via vapor-phase self-assembly. This vapor-phase self-assembly takes place in a vacuum chamber. An optical mold roller with the protective layer 4 deposited on it is placed inside the vacuum chamber, and a liquid source of fluorosilane is heated to evaporate it into vapor. The vapor diffuses under vacuum conditions onto the protective layer 4 on the surface of the mold roller, where the fluorosilane molecules spontaneously arrange themselves into a highly ordered monolayer through chemisorption. Specifically, the trichlorosilane group (-SiCl3) in the fluorosilane molecules first undergoes a hydrolysis reaction with water molecules adsorbed on the surface of protective layer 4 to generate silanol groups (-Si(OH)3). Subsequently, the silanol groups undergo a condensation reaction with the active functional groups (hydroxyl or carboxyl groups) on the surface of protective layer 4 to form siloxane covalent bonds (-Si-OC, where C represents a carbon atom on the surface of protective layer 4), thereby firmly chemically bonding the fluorosilane molecules to the surface of protective layer 4. Meanwhile, adjacent fluorinated silane molecules also form a siloxane crosslinking network (-Si-O-Si-) through the mutual condensation between silanol groups, further enhancing the structural integrity and stability of the anti-adhesion layer 5. Under the mutual repulsion between the perfluorinated alkyl chains and the surface of the protective layer 4, the perfluorinated alkyl chains point away from the protective layer 4, forming a highly ordered self-assembled monolayer.

[0040] The thickness of the anti-adhesion layer 5 is a monolayer thickness, typically from 1 nm to 5 nm, preferably from 1.2 nm to 3 nm. The thickness of the anti-adhesion layer 5 can be adjusted by controlling process parameters such as the temperature of vapor-phase self-assembly, vacuum level, vapor pressure of fluorinated silane, and processing time. For the microstructure of the optical mold roller surface, a monolayer thickness is sufficient to provide the anti-adhesion function without causing a perceptible impact on the feature dimensions of the microstructure.

[0041] The anti-stick layer 5 possesses ultra-low surface energy. The highly fluorinated structure of the perfluorinated alkyl chain (-CF2-CF2-CF3) endows the anti-stick layer 5 with extremely low surface energy and poor wettability. The surface modified with a self-assembled monolayer of fluorinated silane can achieve a water contact angle exceeding 110° and a surface energy as low as below 11 mN / m. This ultra-low surface energy makes it difficult for liquid UV adhesive to wet and spread on the mold surface, significantly reducing the adhesion between the cured resin and the mold, thus achieving excellent release properties.

[0042] More importantly, the fluorinated alkyl chains of the anti-adhesion layer 5 actively repel polar organic monomers in the liquid UV adhesive at the chemical level. Due to the strong hydrophobic and oleophobic properties of the perfluorinated alkyl chains, there is significant thermodynamic incompatibility between them and the acrylate polar monomers in the liquid UV adhesive. When the liquid UV adhesive is extruded into the microstructure of the mold surface, the fluorinated alkyl chains of the anti-adhesion layer 5 repel the wetting and spreading of the liquid resin at the molecular level, reducing the effective contact area and contact time between the liquid resin and the mold surface. During UV curing, this chemical repulsion inhibits the interdiffusion and entanglement of molecular chains at the interface between the cured resin and the mold resin, resulting in a physical adhesion rather than a chemical adhesion between the cured resin and the mold, thus achieving clean interface peeling during demolding and avoiding resin residue. Furthermore, the dense arrangement of fluorinated alkyl chains in the anti-adhesion layer 5 further fills and seals any nanoscale defects or micropores that may exist on the surface of the protective layer 4, forming a complete barrier together with the protective layer 4.

[0043] The anti-adhesion layer 5 is firmly bonded to the surface of the protective layer 4 via siloxane covalent bonds (-Si-OC). Siloxane covalent bonds have high bond energy and excellent chemical stability in organic solvent environments, ensuring that the anti-adhesion layer 5 maintains stable chemical adhesion even under long-term contact with liquid UV adhesives containing organic solvents, and is not prone to desorption or degradation. This contrasts sharply with existing fluorinated anti-adhesion layers linked by ester bonds: ester bonds are prone to alcoholysis or transesterification in acrylate organic solvents, leading to anti-adhesion layer detachment, while siloxane covalent bonds exhibit excellent solvent resistance.

[0044] In summary, the protective layer 4 and the anti-adhesion layer 5 work synergistically to form the surface composite layer 45 described in this invention. The protective layer 4, through its dense diamond-like structure, physically blocks the penetration pathways of organic solvent molecules, protecting the resin matrix of the working layer 3 from swelling, deformation, and chemical corrosion. The anti-adhesion layer 5, through its ultra-low surface energy and the chemical repulsion effect of fluorinated alkyl chains, reduces the wettability of the liquid UV adhesive and the interfacial adhesion of the cured resin, inhibiting molecular chain entanglement at the interface. The protective layer 4 provides active anchoring points for chemical bonding in the anti-adhesion layer 5, while the anti-adhesion layer 5 seals the nanoscale defects on the surface of the protective layer 4 and provides chemical repulsion. Functionally and structurally, they are interdependent and mutually reinforcing, jointly providing long-term surface protection for the resin-based optical mold roller when replicating the microstructure of the homologous UV-cured resin.

[0045] The surface composite layer and its preparation method provided by the present invention will be described in detail below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Unless otherwise stated, the raw materials used in the embodiments are commercially available, and the equipment used is conventional equipment in the art.

[0046] Example 1

[0047] This embodiment provides a surface composite layer for an optical mold roller and its preparation method. The optical mold roller (the main body structure is composed of a metal roller core 1, a buffer layer 2 and a working layer 3) is prepared by a metal master roller in conjunction with a roller-to-roll UV imprinting replication process. Its working layer 3 is a UV-curable resin material filled with high-modulus nanoparticles, and the surface of the working layer 3 has a concave-convex pattern for replicating optical microstructures.

[0048] The preparation of the surface composite layer 45 includes the following steps.

[0049] (a) Matrix pretreatment steps.

[0050] The aforementioned optical mold roller was placed in a plasma treatment chamber, and the chamber was evacuated to a base vacuum level of no less than 5 × 10⁻³ Pa. Oxygen was introduced until the chamber pressure reached 20 Pa, and the radio frequency power supply was turned on to perform oxygen plasma treatment on the surface of the mold roller at a power of 100 W for 5 minutes. Oxygen plasma treatment can remove organic contaminants from the surface of the working layer 3, and at the same time introduce oxygen-containing active functional groups such as hydroxyl (-OH) and carboxyl (-COOH) groups onto its surface, providing a good adhesion interface for the subsequent deposition of the diamond-like carbon protective layer.

[0051] (ii) Deposition steps of diamond-like protective layer.

[0052] The pretreated optical mold roller was placed in a plasma-enhanced chemical vapor deposition (PECVD) chamber. High-purity acetylene (C2H2, purity ≥99.9%) was used as the carbon source gas, and high-purity argon (Ar, purity ≥99.999%) was used as the discharge gas. The flow rate ratio of the carbon source gas to the discharge gas was 1:2, i.e., the acetylene flow rate was 20 sccm and the argon flow rate was 40 sccm. The chamber working pressure was controlled at 2.0 Pa. The radio frequency power supply was turned on, with a frequency of 13.56 MHz and a power setting of 150 W. Under plasma excitation, acetylene molecules dissociated into carbon-containing active groups, which were deposited on the microstructure surface of the working layer 3 of the mold roller. During the deposition process, the mold roller rotated at a constant speed of 5 rpm to ensure film thickness uniformity. The deposition temperature was 80℃. The deposition time was 30 minutes. Through the above process, a diamond-like carbon protective layer 4 with a thickness of 50 nm was formed on the surface of the working layer 3.

[0053] After deposition is complete, turn off the RF power supply and gas source, maintain a vacuum state to allow the mold roller to cool naturally to room temperature in the chamber before removing it.

[0054] (iii) Surface activation treatment steps for the protective layer.

[0055] The optical mold roller with the protective layer 4 deposited is placed back into the plasma treatment chamber, and the vacuum level is evacuated to a minimum of 5 × 10⁻³ Pa. Oxygen is introduced until the chamber pressure reaches 15 Pa, and oxygen plasma treatment is performed at 80 W radio frequency power for 3 minutes. The purpose of this step is that the diamond-like carbon layer itself is chemically inert and lacks sufficient active functional groups on its surface; through oxygen plasma treatment, oxygen-containing active functional groups such as hydroxyl and carboxyl groups are introduced into the surface of the diamond-like carbon protective layer 4, providing anchoring points for chemical bonding of the subsequent fluorinated silane anti-adhesion layer 5.

[0056] (iv) The gas-phase self-assembly step of the fluorinated silane anti-adhesion layer.

[0057] The surface-activated mold roller was placed in a vacuum self-assembly chamber. 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FDTS, molecular formula CF3-(CF2)7-(CH2)2-SiCl3) was used as the precursor. The FDTS liquid source was placed in a heated evaporation boat within the chamber and heated to 120°C to evaporate it into vapor. The chamber vacuum was controlled at 0.02 bar (approximately 15 Torr). The mold roller temperature was controlled at 80°C. The vapor diffused under vacuum onto the diamond-like carbon protective layer 4 on the surface of the mold roller, and FDTS molecules self-assembled on the surface of the protective layer 4 through chemical adsorption to form a monolayer. The self-assembly process took 60 minutes.

[0058] During self-assembly, the trichlorosilane group (-SiCl3) in the FDTS molecule first undergoes hydrolysis with trace amounts of water molecules adsorbed on the surface of protective layer 4 to generate silanol groups (-Si(OH)3). Subsequently, the silanol groups undergo condensation with the hydroxyl groups on the surface of protective layer 4 to form siloxane covalent bonds (-Si-OC), firmly chemically bonding the FDTS molecules to the surface of protective layer 4. Adjacent FDTS molecules also form a siloxane crosslinking network (-Si-O-Si-) through mutual condensation between silanol groups, further enhancing the structural integrity of the anti-adhesion layer 5. Under the driving force of self-assembly, the perfluorinated alkyl chain (-CF2-CF2-CF3) of the FDTS molecule points away from the protective layer 4, forming a highly ordered self-assembled monolayer. The thickness of the obtained anti-adhesion layer 5 is approximately 2 nm.

[0059] After self-assembly, turn off the heating power, maintain a vacuum state, and allow the mold roller to cool naturally to room temperature before removing it. At this point, a surface composite layer 45, consisting of a protective layer 4 and an anti-stick layer 5, is formed on the surface of the working layer 3 of the resin-based optical mold roller.

[0060] Example 2

[0061] The difference between this embodiment and Embodiment 1 lies in the deposition process parameters of the diamond-like carbon protective layer.

[0062] The matrix pretreatment steps are the same as in Example 1.

[0063] The deposition of the diamond-like carbon (DLC) protective layer employed the following process parameters: high-purity methane (CH4) was used as the carbon source gas, and high-purity argon was used as the discharge gas. The flow rate ratio of the carbon source gas to the discharge gas was 1:3, i.e., the methane flow rate was 15 sccm and the argon flow rate was 45 sccm. The chamber operating pressure was controlled at 3.0 Pa. The radio frequency power was set to 200 W. The deposition temperature was 60℃. The deposition time was 20 minutes. The die roller rotation speed was 5 rpm. Following the above process, a DLC protective layer 4 with a thickness of approximately 35 nm was formed on the surface of the working layer 3.

[0064] The surface activation treatment steps for the protective layer are the same as in Example 1.

[0065] The vapor-phase self-assembly of the fluorinated silane anti-adhesion layer was performed using the following process parameters: 1H,1H,2H,2H-perfluorooctyltrichlorosilane (FOTS, molecular formula CF3-(CF2)5-(CH2)2-SiCl3) was used as the precursor. The FOTS liquid source was heated to 110°C to evaporate into vapor. The chamber vacuum was controlled at 5 Torr (approximately 6.7 × 10⁻³ bar). The mold roller temperature was controlled at 60°C. The self-assembly time was 45 minutes. Following this process, a FOTS self-assembled monolayer was formed on the surface of the diamond-like carbon protective layer 4 as the anti-adhesion layer 5, with a thickness of approximately 1.5 nm.

[0066] The remaining steps are the same as in Example 1.

[0067] Example 3

[0068] The difference between this embodiment and Embodiment 1 is that the diamond-like protective layer uses different carbon source gas and deposition parameters.

[0069] The matrix pretreatment steps are the same as in Example 1.

[0070] The deposition of the diamond-like carbon (DLC) protective layer employed the following process parameters: high-purity benzene (C6H6) vapor was used as the carbon source gas, and high-purity argon was used as the carrier gas. Benzene vapor was carried into the deposition chamber by argon gas via bubbling, with a bubbling temperature of 25°C. The flow rate ratio of the carbon source gas to the discharge gas was 1:4, i.e., the benzene vapor flow rate was 10 sccm (converted to standard conditions), and the argon flow rate was 40 sccm. The chamber operating pressure was controlled at 1.5 Pa. A pulsed microwave surface wave plasma source was used, with a pulsed microwave power of 800 W, a pulse frequency of 1 kHz, and a duty cycle of 50%. The deposition temperature was 40°C. The deposition time was 15 minutes. The die roller rotation speed was 8 rpm. Following the above process, a diamond-like carbon (DLC) protective layer 4 with a thickness of approximately 25 nm was formed on the surface of the working layer 3.

[0071] The surface activation treatment steps for the protective layer are the same as in Example 1.

[0072] The vapor-phase self-assembly of the fluorinated silane anti-adhesion layer was performed using the following process parameters: Tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane (F13-TCS, molecular formula CF3-(CF2)5-(CH2)2-SiCl3) was used as the precursor. The F13-TCS liquid source was heated to 100°C to evaporate into vapor. The chamber vacuum was controlled at 10 Torr. The mold roller temperature was controlled at 50°C. The self-assembly time was 90 minutes. Following this process, an F13-TCS self-assembled monolayer was formed on the surface of the diamond-like carbon protective layer 4 as the anti-adhesion layer 5, with a thickness of approximately 1.8 nm.

[0073] The remaining steps are the same as in Example 1.

[0074] Example 4

[0075] The difference between this embodiment and Embodiment 1 is that the diamond-like protective layer is deposited with higher power and a thicker thickness.

[0076] The matrix pretreatment steps are the same as in Example 1.

[0077] The deposition of the diamond-like carbon (DLC) protective layer employed the following process parameters: high-purity acetylene (C2H2) was used as the carbon source gas, and high-purity argon was used as the discharge gas. The flow rate ratio of the carbon source gas to the discharge gas was 1:1.5, i.e., the acetylene flow rate was 25 sccm and the argon flow rate was 38 sccm. The chamber operating pressure was controlled at 2.5 Pa. The radio frequency power was set to 250 W. The deposition temperature was 100℃. The deposition time was 60 minutes. The die roller rotation speed was 3 rpm. Following the above process, a diamond-like carbon (DLC) protective layer 4 with a thickness of approximately 100 nm was formed on the surface of the working layer 3.

[0078] The surface activation treatment steps for the protective layer are the same as in Example 1.

[0079] The vapor-phase self-assembly of the fluorinated silane anti-adhesion layer employed the same process parameters as in Example 1: FDTS was used as the precursor, heated to 120°C, with a chamber vacuum of 0.02 bar, a mold roller temperature of 80°C, and a self-assembly time of 60 minutes. Following this process, an FDTS self-assembled monolayer was formed on the surface of the diamond-like carbon protective layer 4 as the anti-adhesion layer 5, with a thickness of approximately 2 nm.

[0080] The remaining steps are the same as in Example 1.

[0081] Example 5

[0082] The difference between this embodiment and Embodiment 1 is that the fluorinated silane anti-adhesion layer uses a higher self-assembly temperature and a longer processing time.

[0083] The matrix pretreatment steps are the same as in Example 1.

[0084] The deposition of the diamond-like carbon protective layer used the same process parameters as in Example 1: acetylene as the carbon source gas (20 sccm), argon as the discharge gas (40 sccm), chamber pressure 2.0 Pa, radio frequency power 150 W, deposition temperature 80℃, and deposition time 30 minutes, forming a diamond-like carbon protective layer 4 with a thickness of approximately 50 nm.

[0085] The surface activation treatment steps for the protective layer are the same as in Example 1.

[0086] The vapor-phase self-assembly of the fluorinated silane anti-adhesion layer employs the following process parameters: FDTS is used as a precursor, and the FDTS liquid source is heated to 130°C to evaporate into vapor. The chamber vacuum is controlled at 0.025 bar. The mold roller temperature is controlled at 100°C. The self-assembly processing time is 120 minutes. Following this process, an FDTS self-assembled monolayer, approximately 2.5 nm thick, is formed on the surface of the diamond-like carbon protective layer 4 as the anti-adhesion layer 5.

[0087] The remaining steps are the same as in Example 1.

[0088] The following comparative examples illustrate the synergistic advantages of the surface composite layer provided by the present invention. Unless otherwise specified, the process steps in each comparative example are the same as in Example 1.

[0089] Comparative Example 1

[0090] This comparative example provides an optical mold roller without surface composite layer treatment.

[0091] Except for the absence of diamond-like carbon protective layer deposition and fluorinated silane anti-adhesion layer self-assembly, the remaining structure is the same as in Example 1. Specifically, the optical mold roller includes a metal roller core 1, a buffer layer 2, and a working layer 3 with a microstructured surface. The surface of the working layer 3 is not treated with any surface composite layer.

[0092] Comparative Example 2

[0093] This comparative example provides an optical mold roller with only a diamond-like protective layer deposited on it and without a fluorinated silane anti-stick layer.

[0094] The preparation of the surface composite layer only included the substrate pretreatment and diamond-like carbon protective layer deposition steps as in Example 1, and the deposition process parameters were the same as in Example 1. No surface activation treatment of the protective layer or vapor-phase self-assembly of the fluorinated silane anti-adhesion layer was performed, nor were any other anti-adhesion treatments performed.

[0095] Comparative Example 3

[0096] This comparative example provides an optical mold roller with only a fluorinated silane anti-adhesion layer and no diamond-like protective layer.

[0097] The preparation of the surface composite layer only included substrate pretreatment and the vapor-phase self-assembly of the fluorinated silane anti-adhesion layer. The substrate pretreatment was the same as in Example 1. Subsequently, vapor-phase self-assembly was performed using FDTS as a precursor, with the same process parameters as in Example 1. No diamond-like carbon protective layer was deposited.

[0098] Comparative Example 4

[0099] This comparative example provides an optical mold roller that uses a traditional ester bond connection method to construct a fluorinated anti-stick layer.

[0100] First, a 50 nm thick diamond-like carbon protective layer 4 is deposited on the surface of the working layer 3 using the same process parameters as in Example 1. Then, an ester-bonded fluorinated anti-adhesion layer is prepared on the surface of the protective layer 4, instead of the siloxane-bonded fluorinated silane anti-adhesion layer used in this invention. The specific preparation method is as follows:

[0101] A mold roller with a diamond-like carbon protective layer 4 deposited on it was immersed in an ethanol solution of perfluorooctanoic acid (PFOA, molecular formula CF3-(CF2)6-COOH) at a concentration of 0.1 mol / L, at a temperature of 60°C, for 120 minutes. After immersion, the roller was removed and repeatedly rinsed with anhydrous ethanol to remove residual molecules adsorbed by physical adsorption. It was then dried in an oven at 120°C for 30 minutes. During this process, the carboxyl groups (-COOH) of PFOA undergo a dehydration condensation reaction with the hydroxyl groups (-OH) introduced from the surface of the protective layer 4 after activation by oxygen plasma, forming ester bonds (-COO-C). This ester bond connects the perfluorinated alkyl chain to the surface of the protective layer 4. This comparative example simulates the technical route of bonding the fluorinated anti-adhesion layer to the oxide surface via ester bonds in the prior art CN 102433562 A.

[0102] Comparative Example 5

[0103] This comparative example provides an optical mold roller with a diamond-like protective layer and a common alkylsilane anti-sticking layer deposited on it.

[0104] The deposition process parameters for the diamond-like carbon protective layer were the same as in Example 1. The surface activation treatment of the protective layer was also the same as in Example 1. The vapor-phase self-assembly of the anti-adhesion layer was performed using dodecyltrichlorosilane (DTS, molecular formula CH3-(CH2)). 11 -SiCl3) was used instead of FDTS as the precursor, and the process parameters were the same as in Example 1, namely, DTS was heated to 120°C, the chamber vacuum degree was 0.02 bar, the mold roller temperature was 80°C, and the self-assembly time was 60 minutes. After the above process, a dodecyltrichlorosilane self-assembled monolayer was formed on the surface of the diamond-like protective layer 4 as an anti-adhesion layer.

[0105] The performance of the optical mold rollers prepared in the above embodiments and comparative examples was then tested. After cutting samples from the optical mold rollers of each embodiment and comparative example, various performance tests were performed. These tests included solvent swelling resistance testing, interfacial peel force testing, contact angle testing, anti-adhesion layer chemical stability testing, and simulated continuous embossing lifespan testing.

[0106] The solvent swelling resistance test was used to evaluate the barrier effect of the surface composite layer against organic solvent penetration, i.e., the physical barrier function of protective layer 4. During the test, samples with microstructured surfaces were cut from the optical mold rollers of each embodiment and comparative example, with sample dimensions of 20 mm × 20 mm × 5 mm. The samples were completely immersed in methyl acrylate monomer at 25 degrees Celsius for 72 hours. After immersion, the samples were removed, and residual liquid was gently absorbed with filter paper. Immediately afterward, the characteristic dimensions of the microstructure on the sample surface were measured using a three-dimensional non-contact optical profilometer at 25 degrees Celsius. Measurements were taken at least 10 different locations on each sample, and the average value was recorded. The swelling rate was calculated using the following formula: the swelling rate equals the characteristic dimension of the microstructure after immersion minus the initial value of the characteristic dimension of the microstructure before immersion, divided by the initial value of the characteristic dimension of the microstructure before immersion multiplied by 100%. The lower the swelling rate, the stronger the ability of the surface composite layer to block organic solvent penetration.

[0107] The interfacial peel force test was used to evaluate the interfacial adhesion between the cured resin and the mold surface, i.e., the chemical repulsion function of the anti-adhesion layer 5. The test was conducted using a roller-to-roll embossing simulation device. Optical mold roller samples from each embodiment and comparative example were fixed on a flat base. A uniformly thick layer of UV-curable resin was coated onto the sample surface. This resin was the same type used in optical film production, and its main components were acrylate monomers and photoinitiators. A flat metal plate treated with anti-adhesion coating was placed over the resin layer. The surface of the metal plate was treated with FDTS self-assembled monolayers, and pressure was applied to ensure a uniform resin layer thickness. Irradiation curing was performed using a 365 nm LED UV lamp at an irradiation intensity of 100 mW per square centimeter for 60 seconds. After curing, the metal plate was peeled off the sample surface at a 180-degree angle. The average peel force during the peeling process was recorded using a digital tensile tester, expressed in Newtons per centimeter. Each sample underwent at least five tests, and the average value was taken. A lower peel force indicates a weaker interfacial adhesion between the cured resin and the mold surface, and superior demolding performance.

[0108] Contact angle testing was used to evaluate the surface energy state of the anti-adhesion layer 5, namely the integrity and hydrophobic properties of the fluorinated silane self-assembled monolayer. Static contact angle measurements were performed on the surfaces of the optical mold rollers in each embodiment and comparative example using a contact angle meter. The test liquid was deionized water with a droplet volume of 2 μL. Measurements were taken at least five different locations for each sample, and the average value was calculated. A higher contact angle indicates a lower surface energy and a more complete and ordered coverage of the anti-adhesion layer 5.

[0109] The chemical stability test of the anti-adhesion layer was used to evaluate the chemical adhesion stability of the anti-adhesion layer 5 in an organic solvent environment, and was particularly used to distinguish the essential difference in solvent resistance between the siloxane covalent bonds in this invention and the ester bonds in the prior art. The optical mold roller samples of each embodiment and comparative example were placed in methyl acrylate monomer at a temperature of 25 degrees Celsius for 72 hours. After immersion, the samples were removed, and the surface was gently rinsed with anhydrous ethanol to remove physically adsorbed residual monomers. Then, they were dried in an oven at 60 degrees Celsius for 30 minutes. After drying, elemental analysis of the sample surface was performed using X-ray photoelectron spectroscopy, and the atomic percentage of fluorine on the surface was recorded. Simultaneously, the surface water contact angle was measured again using a contact angle meter. The fluorine retention rate and contact angle retention rate were calculated. The fluorine retention rate was equal to the surface fluorine content after immersion divided by the initial fluorine content before immersion multiplied by 100%, and the contact angle retention rate was equal to the contact angle after immersion divided by the initial contact angle before immersion multiplied by 100%. The higher the fluorine retention rate and contact angle retention rate, the better the chemical stability of the anti-stick layer in the organic solvent environment, and the stronger the chemical bond between the anti-stick layer and the protective layer.

[0110] The simulated continuous embossing life test is used to comprehensively evaluate the long-term durability performance of the surface composite layer under simulated actual production conditions. The test employs a laboratory roller-to-roll embossing simulation device for continuous embossing cycle testing. Optical mold roller samples from each embodiment and comparative example are mounted on the roller shaft of the embossing device, with a metal master plate treated with FDTS anti-adhesion as the counter roller. UV-curable resin is continuously coated onto the surface of the mold roller, followed by embossing, curing, and demolding. Each test cycle consists of 100 embossing cycles. After each cycle, samples from the microstructure area on the surface of the mold roller are collected, and the integrity of the microstructure, resin residue, and the detachment of the protective and anti-adhesion layers are observed using a scanning electron microscope. The test is terminated and the number of cycles is recorded when any of the following failure phenomena occur: the microstructure feature size change rate on the mold roller surface exceeds 5%, obvious resin residue or microstructure blockage appears on the mold roller surface, and the protective or anti-adhesion layer on the mold roller surface shows visible peeling or damage.

[0111] The test results of each embodiment and comparative example are shown in Table 1. Among them, comparative examples 1 and 2 did not undergo tests for fluorine retention rate and contact angle retention rate because their surfaces did not contain fluorine.

[0112]

[0113] As can be seen from the test results in Table 1, the surface composite layer of the optical mold roller in each embodiment of the present invention exhibits excellent performance in all performance tests. Regarding solvent swelling resistance, the swelling rate of each embodiment is below 0.15%, with Example 4 showing the lowest swelling rate (0.05%) due to its 100nm protective layer thickness. This indicates that the diamond-like carbon protective layer effectively blocks the penetration of organic solvent molecules, protecting the resin-based working layer from swelling and deformation. In stark contrast, Comparative Example 1, without surface composite layer treatment, has a swelling rate as high as 4.80%, indicating that the resin-based working layer undergoes significant swelling upon direct contact with organic solvents. This leads to irreversible changes in the microstructural feature dimensions, severely affecting the structural accuracy of the optical film product. Comparative Example 3, with only an anti-adhesion layer and no protective layer, also has a swelling rate as high as 4.50%, proving that the fluorinated silane anti-adhesion layer alone cannot prevent organic solvent penetration; a dense physical barrier layer must be placed below the anti-adhesion layer.

[0114] Regarding the interfacial peel force, the peel forces of all embodiments were below 0.42 N / cm. Example 5 exhibited the lowest peel force (0.30 N / cm) due to its longer FDTS self-assembly time and higher orderliness of the anti-adhesion layer. This indicates that the fluorinated silane anti-adhesion layer effectively reduces the interfacial adhesion between the cured resin and the mold surface, making the demolding process smoother. Comparative Example 2, although having a diamond-like carbon protective layer but no anti-adhesion layer, had a peel force as high as 3.80 N / cm. This indicates that with only a hard protective layer and no low surface energy anti-adhesion layer, the cured resin and the mold surface lack chemical repulsion, resulting in strong interfacial adhesion and making demolding difficult. Comparative Example 5, using a non-fluorinated alkyl silane as the anti-adhesion layer, had a peel force of 1.80 N / cm, significantly higher than the peel forces of the embodiments, demonstrating that the chemical repulsion effect of the perfluorinated alkyl chain has an irreplaceable effect on reducing interfacial adhesion. Comparative Example 1, without any surface treatment, had the highest peel force, reaching 4.20 N / cm.

[0115] Regarding surface hydrophobic properties, the water contact angles of all embodiments ranged from 112° to 118°. Example 5 achieved 118° due to its longer FDTS self-assembly time and higher surface coverage density, indicating that the fluorinated silane self-assembled monolayer formed a highly ordered and fully covered ultra-low surface energy film on the protective layer surface. Comparative Example 5, using a non-fluorinated alkyl silane anti-adhesion layer, had a contact angle of only 95°, significantly lower than the embodiments, further verifying the superiority of perfluorinated alkyl chains in imparting ultra-low surface energy. The contact angles of Comparative Examples 1 and 2 were 68° and 72°, respectively, both far lower than the embodiments, indicating that surfaces without an anti-adhesion layer or with only a diamond-like carbon layer do not possess effective hydrophobic properties.

[0116] The results of the chemical stability test of the anti-adhesion layer are particularly noteworthy. After immersion in methyl acrylate monomer for 72 hours, the fluorine retention rate of all examples was above 96.5%, and the contact angle retention rate was above 95.9%, indicating that the chemical bond formed by anchoring fluorinated silane molecules to the surface of the protective layer through siloxane covalent bonds has excellent stability in organic solvent environments. In stark contrast, Comparative Example 4, which uses ester bonds to connect the fluorinated anti-adhesion layer, had a fluorine retention rate of only 52.3% and a contact angle retention rate of only 48.6%, indicating that the ester bonds underwent significant alcoholysis or transesterification reactions in acrylate organic solvents, leading to a large amount of fluorinated anti-adhesion layer detachment. This result shows that the existing technology of connecting fluorinated anti-adhesion layers through ester bonds (such as the technical route disclosed in CN102433562A) cannot maintain stable anti-adhesion performance under long-term contact with organic solvents, while the present invention fundamentally solves this problem by using siloxane covalent bonds to connect the fluorinated silane anti-adhesion layer.

[0117] In simulated continuous embossing life tests, the embossing life of each embodiment exceeded 34,000 cycles. Example 5 achieved 42,800 cycles due to its higher orderliness of the anti-adhesion layer and better synergistic effect between the protective and anti-adhesion layers, while Example 4 achieved 41,200 cycles due to its thicker protective layer. Comparative Example 1, without any surface treatment, failed after only 800 cycles due to severe microstructural swelling and deformation. Comparative Example 3, with only an anti-adhesion layer and no protective layer, failed after 5,200 cycles due to microstructural deformation caused by the penetration and swelling of the resin matrix by organic solvents, demonstrating the indispensability of the physical barrier layer. Although Comparative Example 4 initially performed similarly to the embodiments (swelling rate 0.11%, peel force 0.40 N / cm, contact angle 113°), the anti-adhesion layer slowly detached due to the gradual breakage of ester bonds during long-term use, and failed after 15,800 cycles due to the gradually increasing release force and resin residue, resulting in a significantly shorter lifespan than the embodiments. Comparative Example 5 failed at 22,800 cycles due to insufficient chemical repulsion effect of non-fluorinated alkylsilanes, resulting in resin residue clogging the microstructure and causing difficulties in demolding.

[0118] In summary, the surface composite layer for optical mold rollers provided in the various embodiments of the present invention, through the synergistic effect of the diamond-like carbon protective layer and the fluorinated silane anti-adhesion layer, exhibits significantly superior overall performance compared to the comparative examples in terms of solvent swelling resistance, interfacial anti-adhesion, surface hydrophobicity, chemical stability of the anti-adhesion layer, and simulated continuous embossing lifespan. In particular, the present invention overcomes the fundamental defect of insufficient chemical stability of ester bond linkage schemes in organic solvent environments by establishing a siloxane covalent bond between the fluorinated silane and the protective layer, thus achieving long-term reliable protection for resin-based optical mold rollers when replicating microstructures of homologous UV-cured resins.

[0119] The above description is merely an illustrative embodiment of the present invention and is not intended to limit the scope of the invention. Any equivalent changes, modifications, and combinations made by those skilled in the art without departing from the concept and principles of the present invention should fall within the scope of protection of the present invention.

Claims

1. A method for preparing a surface composite layer for an optical mold roller, the optical mold roller comprising a metal roller core, a buffer layer disposed on the outer surface of the metal roller core, and a working layer disposed on the outer surface of the buffer layer, wherein the surface of the working layer has a microstructure, and the surface composite layer is formed on the surface of the microstructure, characterized in that, The method for preparing the surface composite layer for the optical mold roller includes the following steps: Step 1: Place the optical mold roller in a plasma processing chamber and treat it with 100W radio frequency power for 5 minutes in an oxygen atmosphere to clean the surface of the microstructure and introduce the first active functional group on the surface of the microstructure. Step 2: The optical mold roller processed in Step 1 is placed in a plasma-enhanced chemical vapor deposition chamber. Hydrocarbon is used as the carbon source gas and argon is used as the discharge gas. A diamond-like carbon protective layer is deposited under the conditions of radio frequency power of 100W to 300W and deposition temperature not exceeding 200℃. The deposition time is 10 minutes to 60 minutes. The thickness of the diamond-like carbon protective layer is 10nm to 200nm. Step 3: Place the optical mold roller with the deposited diamond-like protective layer in a plasma processing chamber and treat it with 80W radio frequency power for 3 minutes in an oxygen atmosphere to introduce a second active functional group on the surface of the diamond-like protective layer. Step four: The optical mold roller processed in step three is placed in a vacuum self-assembly chamber. Fluorosilane is used as a precursor and heated to 100°C to 130°C to evaporate it into vapor. The temperature of the optical mold roller is controlled at 50°C to 100°C, and the vacuum degree of the chamber is controlled at 0.005 bar to 0.05 bar. Vapor phase self-assembly is performed for 30 to 120 minutes. The fluorosilane is chemically bonded to the surface of the diamond-like protective layer through siloxane covalent bonds to form a self-assembled monolayer anti-adhesion layer with a thickness of 1 nm to 5 nm.

2. The method according to claim 1, characterized in that, The hydrocarbon is selected from any one of methane, acetylene, or benzene.

3. The method according to claim 1, characterized in that, The deposition temperature in step two is 25°C to 150°C.

4. The method according to claim 1, characterized in that, The fluorinated silane mentioned in step four is selected from any one of 1H,1H,2H,2H-perfluorodecyltrichlorosilane, 1H,1H,2H,2H-perfluorooctyltrichlorosilane, or tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane.

5. The method according to claim 1, characterized in that, The first and second active functional groups are oxygen-containing active functional groups.

6. The surface composite layer for optical mold rollers prepared by the method according to any one of claims 1 to 5, characterized in that, The surface composite layer includes: A protective layer, wherein the material of the protective layer is diamond-like carbon, and the thickness of the protective layer is 10 nm to 200 nm; An anti-adhesion layer is disposed on the outer surface of the protective layer. The anti-adhesion layer is made of fluorinated silane, which is chemically bonded to the surface of the protective layer through siloxane covalent bonds. The anti-adhesion layer is a self-assembled monolayer, and its thickness is 1 nm to 5 nm.

7. The surface composite layer for optical mold rollers according to claim 6, characterized in that, The fluorinated silane is selected from any one of 1H,1H,2H,2H-perfluorodecyltrichlorosilane, 1H,1H,2H,2H-perfluorooctyltrichlorosilane, or tridecafluoro-1,1,2,2-tetrahydrooctyltrichlorosilane.

8. The surface composite layer for optical mold rollers according to claim 6, characterized in that, The thickness of the protective layer is 25nm to 100nm, and the thickness of the anti-adhesion layer is 1.5nm to 3nm.

9. The surface composite layer for optical mold rollers according to claim 6, characterized in that, The deposition temperature of the diamond-like protective layer is not higher than 200°C.

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