An insulating layer, a composite material, and a method for preparing the same.

Abstract

This invention relates to an insulating layer and its preparation method. The insulating layer includes a substrate layer and a protective coating. The protective coating is applied to the substrate layer, and the surface of the substrate layer coated with the protective coating has protrusions and pits. The protrusions include multiple main protrusions, and the ratio of the equivalent height H of the main protrusion to the equivalent diameter D at the bottom, H / D, is ≥1.5. The spacing between adjacent protrusions is 8μm to 12μm. The maximum width of the pits is 50nm to 80nm. The hydrophobic and oleophobic base of the micro-nano multi-level interface, in synergy with the protective coating, makes fingerprints and oil stains on the surface extremely easy to wipe away without residue. This micro-nano composite structure with specific parameters significantly increases the contact area and anchoring effect between the protective coating and the substrate layer, effectively improving the coating adhesion and thus enhancing the wear resistance and durability of the insulating layer surface. This addresses the technical problems of poor fingerprint resistance, easy coating peeling, and insufficient wear resistance of existing black insulating layers from the root of structural design.

Description

Technical Field

[0001] This invention relates to the field of electronic materials technology, and in particular to an insulating layer, a composite material, and a method for preparing the same. Background Technology

[0002] Polyester insulation layers are widely used in screen modules, electronic components, flexible circuit boards and other related fields due to their excellent insulation properties, light-shielding effect and ease of processing. They mainly serve the functions of insulation protection and light shielding, and are one of the commonly used insulating substrates in the electronics industry.

[0003] Currently, most conventional polyester insulation layers on the market have a smooth, flat structure, providing only basic insulation and light-shielding functions, without any specific optimization design for fingerprint resistance. During actual assembly, use, and daily wiping, fingerprints are easily left on the insulation layer surface. The oils, sweat, and other contaminants in fingerprints adhere to the surface, affecting not only the product's appearance and cleanliness but also indirectly impacting the insulation layer's usability and assembly compatibility. This fails to meet the fingerprint-resistant and easy-to-clean requirements of high-end electronic products. Therefore, existing polyester insulation layers generally suffer from poor fingerprint resistance, and the problem of easy fingerprint adhesion urgently needs to be solved. Summary of the Invention

[0004] Therefore, it is necessary to provide an insulating layer, a composite material, and a method for preparing the same to improve the anti-fingerprint effect.

[0005] The technical solution is as follows: an insulating layer, comprising a base layer and a protective coating; the protective coating is applied to the base layer, and the surface of the base layer coated with the protective coating has protrusions and pits, the protrusions including multiple main protrusions, the ratio of the equivalent height H of the main protrusions to the equivalent diameter D of the bottom H / D ≥ 1.5, and the spacing between adjacent main protrusions is 5μm to 10μm; the maximum width of the pits is 50nm to 80nm.

[0006] This embodiment constructs a micro / nano composite structure on the surface of a substrate coated with a protective coating, featuring micron-level main protrusions and nano-level pits working in synergy. This integrated structure, combined with the protective coating, forms a unified functional system, achieving targeted performance enhancement. Specifically, the ratio of the equivalent height H of the main protrusion to the equivalent diameter D of the bottom (H / D ≥ 1.5), along with a uniform spacing of 5μm to 10μm between adjacent main protrusions, forms a highly regular micron-level support framework. This significantly reduces the actual contact area between fingerprint grease and the insulating layer surface, physically preventing fingerprint grease adhesion. Combined with nano-level pits with a maximum width of 50nm to 80nm, this further strengthens the hydrophobic and oleophobic foundation of the micro / nano multi-level interface. Working synergistically with the protective coating, this makes fingerprint grease on the surface extremely easy to wipe away without residue. Simultaneously, this micro / nano composite structure with specific parameters significantly increases the contact area and anchoring effect between the protective coating and the substrate, effectively improving coating adhesion and thus enhancing the wear resistance and durability of the insulating layer surface. This addresses the technical problems of poor fingerprint resistance, easy coating peeling, and insufficient wear resistance in existing black insulating layers from the root of structural design.

[0007] In one embodiment, the cross-sectional width of the main protrusion decreases continuously along the height direction, and the ratio of the equivalent width W1 of the main protrusion at 1 / 2 height to the equivalent diameter D at the bottom, W1 / D, is 0.4 to 0.7.

[0008] In one embodiment, the angle β between the sidewall of the main protrusion and the surface of the base layer is 70° to 85°.

[0009] In one embodiment, the top of the main protrusion is hemispherical or arc-shaped, with a radius of curvature R of 0.3 μm to 0.8 μm.

[0010] In one embodiment, the upper 1 / 3 height region of the main protrusion is provided with micro protrusions, which are distributed on the top end face and side wall of the main protrusion; the height h of the micro protrusions is 0.1μm to 0.5μm, and the bottom width w of the micro protrusions is 0.2μm to 0.8μm.

[0011] In one embodiment, the angle β1 between the sidewall tangent of the main protrusion at 1 / 3 of its height and the surface of the base layer is 75° to 88°.

[0012] In one embodiment, at least 70% of the main protrusions have a height H of 1.5 μm to 4.5 μm and a bottom equivalent diameter D of 0.8 μm to 2.5 μm.

[0013] In one embodiment, the center-to-center distance between adjacent pits is 100 nm to 200 nm.

[0014] In one embodiment, the depth of the pit is 30 nm to 60 nm.

[0015] In one embodiment, the pits are distributed in the gap region between adjacent main protrusions, and the inner wall of the pits is not directly connected to the side wall of the main protrusions.

[0016] In one embodiment, the minimum distance between the edge of the recess and the main protrusion is 0.8 μm to 1.5 μm.

[0017] In one embodiment, the ratio of the depth h of the recess to the height H of the main protrusion is h / H≤0.04.

[0018] In one embodiment, the surface roughness Ra of the base layer having the main protrusion and the pit is 0.12μm to 0.25μm, and the profile arithmetic mean deviation Rz is 0.6μm to 1.2μm.

[0019] In one embodiment, the distribution density of the pits per unit area of ​​the substrate coating surface is 8×10⁵ pits / cm² to 3×10⁶ pits / cm².

[0020] In one embodiment, the distribution density of the main protrusions per unit area of ​​the substrate coating surface is 5×10⁴ protrusions / cm² to 2×10⁵ protrusions / cm².

[0021] In one embodiment, the protective coating has a coating thickness of 0.2 μm to 0.3 μm on the top of the main protrusion and a coating thickness of 0.3 μm to 0.4 μm on the bottom of the pit.

[0022] Furthermore, the coating thickness difference at uneven surfaces is ≤0.2μm.

[0023] In one embodiment, the protective coating is any one of a perfluoropolyether coating, a perfluorooctyltriethoxysilane coating, or a fluorinated acrylate coating.

[0024] In one embodiment, the thickness of the protective coating is 0.2 μm to 0.4 μm.

[0025] A composite material includes an insulating layer, an adhesive layer, a copper foil layer, and a conductive adhesive layer as described above. The adhesive layer is disposed between the insulating layer and the copper foil layer, and the conductive adhesive layer is disposed on the side of the copper foil layer away from the adhesive layer. The side of the conductive adhesive layer away from the copper foil layer is used to adhere and fix it to the screen surface. This composite material integrates an insulating layer, an adhesive layer, a copper foil layer, and a conductive adhesive layer, possessing multiple functions such as excellent fingerprint resistance, high surface wear resistance, insulation protection, conductivity, and screen adhesion. The insulating layer ensures that fingerprints are easily wiped away without residue and that it is wear-resistant and durable. The copper foil layer meets the conductivity requirements, the conductive adhesive layer can firmly adhere to the screen surface, and the adhesive layer ensures that the structure of each layer is tightly bonded and does not delaminate. The entire structure is adaptable to screen modules and other scenarios, is easy to install, has stable overall performance, and is highly practical.

[0026] A method for preparing an insulating layer, comprising the steps described above:

[0027] (1) The substrate layer is subjected to surface cleaning, etching, washing and drying in sequence, and then subjected to micro-nano structure roughening treatment to obtain a rough surface with micron-scale protrusions and nano-scale pits.

[0028] (2) Prepare the vapor deposition raw material for the protective coating and pretreat the raw material;

[0029] (3) The substrate layer after step (1) is placed in a vacuum evaporation equipment and the protective coating is formed on its rough surface by vacuum evaporation process.

[0030] (4) After the base layer is deposited by vapor deposition, post-processing is performed to fix the protective coating and obtain the insulating layer.

[0031] This preparation method ensures that the insulation layer performance accurately meets the standards through a step-by-step process of pretreatment, micro / nano structure forming, vacuum evaporation coating, and post-treatment shaping: First, the substrate layer is cleaned and etched to ensure that the micro / nano protrusions and pits are formed regularly and without impurities; the vacuum evaporation process allows the protective coating to uniformly cover the micro / nano structure, with controllable coating thickness and tight bonding; the post-treatment process allows the coating to fully set, further improving adhesion and wear resistance; the overall process has strong controllability and high yield, and the resulting insulation layer has stable anti-fingerprint and wear resistance properties, making it suitable for industrial mass production. Attached Figure Description

[0032] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0033] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 This is a schematic diagram of the microstructure of the insulating layer described in one embodiment;

[0035] Figure 2 This is a schematic diagram of the microstructure of the insulating layer described in one embodiment;

[0036] Figure 3 This is a schematic diagram of the microstructure of the insulating layer described in another embodiment;

[0037] Figure 4 This is a flowchart of an insulating layer preparation method described in one embodiment.

[0038] In the diagram: 10, base layer; 11, protrusion; 12, pit; 20, protective coating. Detailed Implementation

[0039] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0040] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0041] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0042] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0044] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0045] like Figure 1 As shown, in one embodiment of the present invention, an insulating layer includes a base layer 10 and a protective coating 20; the protective coating 20 is coated on the base layer 10, and the surface of the base layer 10 coated with the protective coating 20 is provided with protrusions 11 and pits 12. The protrusions 11 include a plurality of main protrusions, and the ratio of the equivalent height H of the main protrusions to the equivalent diameter D of the bottom is H / D≥1.5. The spacing between adjacent protrusions 11 is 5μm to 10μm; the maximum width of the pits 12 is 50nm to 80nm.

[0046] This embodiment constructs a micro-nano composite structure on the surface of a substrate coated with a protective coating, featuring micron-level main protrusions and nano-level pits 12 working in synergy. This structure, combined with the protective coating, forms an integrated functional system, achieving targeted performance enhancement. Specifically, the ratio of the equivalent height H of the main protrusion to the equivalent diameter D of the bottom (H / D ≥ 1.5), along with a uniform spacing of 5μm to 10μm between adjacent main protrusions, forms a highly regular micron-level support framework. This significantly reduces the actual contact area between fingerprint grease and the insulating layer surface, physically blocking fingerprint grease adhesion. The nano-level pits 12, with a maximum width of 50nm to 80nm, further strengthen the hydrophobic and oleophobic foundation of the micro-nano multi-level interface. Working synergistically with the protective coating, this makes fingerprint grease on the surface extremely easy to wipe away without residue. Simultaneously, this micro-nano composite structure with specific parameters significantly increases the contact area and anchoring effect between the protective coating and the substrate, effectively improving coating adhesion and thus enhancing the wear resistance and durability of the insulating layer surface. This addresses the technical problems of poor fingerprint resistance, easy coating peeling, and insufficient wear resistance in existing black insulating layers from the root of structural design. It should be noted that the maximum width of the recess 12 is the maximum distance from one point on the edge of the recess 12 to another point on the edge. The recess 12 is usually an approximately spherical or three-dimensional shape with curved surface features.

[0047] Furthermore, Figure 2 The microstructure of a pit 12 and a protrusion 11 is shown using an integral molding process. Figure 3 The recess 12 is integrally formed on the base layer 10, while the protrusion 11 is formed on the base layer 10 by subsequent processes. Meanwhile, Figure 2 and Figure 3 The protective coating 20 is uniformly coated on the base layer 10, but the surface of the base layer 10 has pits 12 and protrusions 11, so the protective coating 20 also forms an uneven surface. Figure 1 This is the microstructure of the protective coating 20 after surface smoothing treatment in one embodiment.

[0048] Figure 2 The integral molding process involved includes etching molding or pressing molding. In etching molding, a composite mask with a preset pattern of pits 12 and protrusions 11 is attached to the surface of the cleaned substrate layer 10. The substrate layer 10 is simultaneously etched using a micro-nano level etching process. By limiting the pattern of the mask, micron-level protrusions 11 and nano-level pits 12 are simultaneously formed on the surface of the substrate layer 10. After etching is completed, the surface mask is removed.

[0049] The compression molding method involves preheating and softening the cleaned substrate 10, then precisely pressing a molding template with complementary micro-nano patterns of pits 12 and protrusions 11 onto the softened surface of the substrate 10, maintaining the compression and shaping state until the substrate 10 cools and hardens, and then demolding. This process simultaneously presses micron-level protrusions 11 and nano-level pits 12 onto the surface of the substrate 10.

[0050] Figure 3 The process involves integrally molding the recesses 12, with the protrusions 11 formed on the substrate layer 10 by subsequent processes. The process for the protrusions 11 involves locally preheating and softening the substrate with only the recesses 12, precisely fitting a molding template with complementary micron patterns of the protrusions 11 to the gap area of ​​the recesses 12 on the substrate, pressing, shaping, and demolding to complete the fabrication of the micron-level protrusions 11.

[0051] Optionally, the height of the protrusion 11 can be 1.0μm, 1.1μm, 1.2μm, 1.3μm, 1.4μm, 1.5μm, 1.6μm, 1.7μm, 1.8μm, 1.9μm, or 2.0μm; the spacing between the protrusions 11 can be 8.0μm, 8.2μm, 8.4μm, 8.6μm, 8.8μm, 9.0μm, 9.2μm, 9.4μm, 9.6μm, 9.8μm, 10.0μm, 10.2μm, 10.4μm, 10.6μm, 10.8μm, 11.0μm, 11.2μm, 11.4μm, 11.6μm, 11.8μm, or 12.0μm.

[0052] Optionally, the aperture of the recess 12 can be 50nm, 52nm, 54nm, 56nm, 58nm, 60nm, 62nm, 64nm, 66nm, 68nm, 70nm, 72nm, 74nm, 76nm, 78nm, or 80nm.

[0053] It should be noted that the insulating layer is a black insulating layer. The base layer 10 is black, while the protective coating 20 may or may not be black. The base layer 10 is a PET material. Carbon black and titanium black are added to the PET material, with a mass ratio of carbon black to titanium black of 3:2. The mass of carbon black and titanium black accounts for 6% to 9% of the total mass of the PET. The two pigments work synergistically to color and block light. Carbon black enhances basic light-blocking properties, while titanium black strengthens light-blocking uniformity and reduces light reflection. A proper ratio of the two maximizes the light-blocking effect. Simultaneously, controlling the addition amount avoids insufficient light blocking due to too little addition, or excessive addition causing the PET layer 20 to become brittle and reducing interlayer bonding strength, thus balancing light-blocking performance and material toughness.

[0054] Furthermore, the carbon black has a particle size of 0.2μm to 0.4μm, and the titanium black has a particle size of 0.3μm to 0.5μm. This particle size range is compatible with the 3:2 mass ratio of the two pigments, ensuring uniform dispersion of the two pigments in the PET raw material, avoiding local pigment agglomeration that forms light-transmitting points, and is also compatible with PET melt extrusion and stretch molding processes without affecting the molding quality of PET, further improving the light-blocking uniformity of PET and enhancing the overall synergistic light-blocking effect.

[0055] In one embodiment, the cross-sectional width of the main protrusion decreases continuously along its height, and the ratio W1 / D of the equivalent width W1 at half the height to the equivalent diameter D at the bottom is 0.4 to 0.7. This results in a regular conical shape that narrows uniformly from top to bottom, maintaining high rigidity to further reduce the oil contact area while avoiding excessively steep or bulky sidewalls. This ensures that the protective coating is uniformly applied along the height of the protrusion without local accumulation or defects, improving the surface oleophobicity and coating structural stability.

[0056] In one embodiment, the angle β between the sidewall of the main protrusion and the surface of the substrate layer is 70° to 85°. Positioning the protrusion sidewall within the optimal range of moderate steepness increases the interlocking and anchoring area between the protective coating and the substrate layer, significantly enhancing coating adhesion and preventing detachment. Furthermore, it avoids situations where an excessively small angle leads to easy coating peeling, while an excessively large angle reduces the anti-fingerprint effect, thus balancing structural strength with surface hydrophobic and oleophobic properties.

[0057] In one embodiment, the top of the main protrusion is hemispherical or arc-shaped, with a radius of curvature R of 0.3μm to 0.8μm. This eliminates stress concentration defects in the coating caused by sharp edges and prevents the protective coating from cracking and peeling off at the top of the protrusion. At the same time, the arc-shaped top surface can further optimize the surface droplet contact morphology, improve the hydrophobic and oleophobic angles, making it more difficult for fingerprints and oil stains to adhere, wiping is smoother and leaves no residue, and the feel is better.

[0058] In one embodiment, the upper third of the height region of the main protrusion is provided with micro-protrusions, which are distributed on the top end face and sidewalls of the main protrusion. The height h of the micro-protrusions is 0.1μm to 0.5μm, and the bottom width w of the micro-protrusions is 0.2μm to 0.8μm. Without changing the spacing of the main protrusions, the actual contact area of ​​fingerprint grease is significantly reduced. Even if the top of the main protrusion is slightly worn, the micro-protrusions can still maintain a stable anti-fingerprint effect. At the same time, the micro-protrusions can enhance the anchoring effect of the coating, significantly improving the surface wear resistance and service life.

[0059] In one embodiment, the angle β1 between the sidewall tangent of the main protrusion at 1 / 3 of its height and the surface of the base layer is 75° to 88°. This gives the upper region of the protrusion a higher steepness, strengthens the support of the top structure, and prevents the top of the protrusion from collapsing and deforming during pressing and wiping. At the same time, it forms a gradient angle with the lower sidewall, which is compatible with the coating characteristics of the protective coating, ensuring that the coating adheres tightly and has a uniform thickness throughout the entire height of the protrusion, further improving the durability and fingerprint resistance of the insulating layer.

[0060] In one embodiment, the ratio of the depth h of the pit 12 to the height H of the main protrusion is h / H ≤ 0.04. Maintaining a shallow, nanoscale recess morphology for the pit 12 not only complements the main protrusion to enhance the micro-nano composite interface structure and improve surface hydrophobic and oleophobic effects, but also prevents the protective coating from accumulating at the bottom of the pit due to excessive depth, resulting in uneven thickness and ensuring the overall smoothness and structural stability of the protective coating. Simultaneously, the shallow pit 12 does not compromise the structural strength of the substrate layer, avoiding a decrease in the mechanical properties of the substrate layer due to excessive depth, thus balancing fingerprint resistance and the structural reliability of the insulating layer.

[0061] In one embodiment, the surface roughness Ra of the substrate layer 10, which includes the main protrusion and the pit 12, is 0.12 μm to 0.25 μm, and the arithmetic mean deviation of the profile Rz is 0.6 μm to 1.2 μm. This maintains the hydrophobic and oleophobic advantages of the micro / nano structure, ensuring fingerprint resistance, while avoiding the problem of excessive roughness causing dirt to stick and be difficult to clean, further optimizing surface cleanliness and making fingerprint wiping more convenient.

[0062] In one embodiment, the distribution density of the pits 12 per unit area of ​​the substrate layer 10 coated surface is 8 × 10⁵ pits / cm² to 3 × 10⁶ pits / cm². The reasonable density of the nano-pits 12 uniformly refines the hydrophobic interface, further reducing fingerprint adhesion points and enhancing the anti-fingerprint effect, while ensuring surface structural uniformity and avoiding local performance imbalances. It should be noted that the unit area is 1 square centimeter (1 cm²).

[0063] In one embodiment, the distribution density of the main protrusions per unit area on the coated surface of the substrate layer 10 is 5 × 10⁴ protrusions / cm² to 2 × 10⁵ protrusions / cm². The moderate density of the micron-sized protrusions 11 ensures both physical delamination and prevents coating buildup and cracking of the protrusions 11 due to excessive density, thus balancing anti-fingerprint performance and structural stability, and improving wear resistance lifespan. It should be noted that the unit area is 1 square centimeter (1 cm²).

[0064] In one embodiment, the protrusion 11 is a frustum-shaped or hemispherical protrusion 11. The frustum-shaped or hemispherical protrusion 11 has no sharp edges, which prevents fingerprints, dirt, and dust from getting stuck in the crevices, further reducing cleaning difficulty. At the same time, it improves the pressure resistance and wear resistance of the protrusion 11 structure, reducing damage under stress.

[0065] In one embodiment, the pits 12 are distributed in the gap area between adjacent protrusions 11, and the inner wall of the pit 12 is not directly connected to the side wall of the protrusion 11. The pits 12 and the protrusions 11 are independent micro-nano structures with no connecting gaps. Fingerprint grease, dust and impurities can only adhere to the surface of a single structure and cannot penetrate into the dead corners of multiple interconnected layers. This avoids the accumulation of stains that are difficult to clean and ensures that stains can be completely removed from the surface during wiping, further guaranteeing long-term cleanliness and anti-fingerprint effect.

[0066] In one embodiment, the minimum distance between the edges of the recess 12 and the protrusion 11 is 0.8 μm to 1.5 μm. This avoids structural interference that could lead to molding defects, while ensuring that the protective coating 20 can fully fill the gaps and cover the structure, resulting in a more continuous coating formation and simultaneous improvement in adhesion and wear resistance.

[0067] In one embodiment, at least 70% of the main protrusions have a height H of 1.5 μm to 4.5 μm and a bottom equivalent diameter D of 0.8 μm to 2.5 μm. This ensures that the vast majority of the main protrusions are within the optimal morphology and size range, resulting in a highly uniform microstructure distribution on the substrate surface. This, in turn, achieves overall uniformity in the anti-fingerprint and hydrophobic / oleophobic properties of the insulating layer. Simultaneously, the regular and uniform size of the main protrusions ensures a stable and consistent bonding and anchoring effect between the protective coating and the substrate, avoiding problems such as insufficient local coating adhesion and easy wear due to excessive differences in the size of the main protrusions, further improving the overall performance and lifespan of the insulating layer.

[0068] In one embodiment, the center-to-center distance between adjacent pits 12 is 100nm to 200nm. The nano-pits 12 are uniformly arranged, with strong consistency in the hydrophobic interface, no local differences in the anti-fingerprint effect, and uniform cleanliness after wiping.

[0069] In one embodiment, the depth of the pit 12 is 30nm to 60nm. The depth of the pit 12 is adapted to the coating characteristics of the protective coating 20, and the coating can completely fill the pit 12 without leaving any cavity residue. This not only enhances the hydrophobic and oil-locking effect, but also avoids the wear resistance from decreasing due to the thin coating at the depth of the pit 12.

[0070] In one embodiment, the protective coating 20 has a coating thickness of 0.2 μm to 0.3 μm on the top of the main protrusion and 0.3 μm to 0.4 μm on the bottom of the recess 12. The moderate coating thickness on the top of the protrusion 11 ensures the hydrophobic and fingerprint-resistant effect, while the slightly thicker coating at the bottom of the recess 12 fills the structural gaps, further improving the long-term stability of surface wear resistance and fingerprint resistance.

[0071] Furthermore, the coating thickness difference between uneven areas is ≤0.2μm. This controllable thickness difference prevents the coating from being too thin and prone to wear, or too thick and prone to peeling, thus further improving the long-term stability of surface abrasion resistance and anti-fingerprint performance.

[0072] In one embodiment, the protective coating 20 is any one of a perfluoropolyether coating, a perfluorooctyltriethoxysilane coating, or a fluorinated acrylate coating. Fluorinated materials themselves possess excellent hydrophobic and oleophobic properties, which, in conjunction with the micro-nano structure, amplify the anti-fingerprint effect. Fingerprints can be wiped away with a single click without leaving any residue, while also being resistant to chemical corrosion and not prone to aging.

[0073] In one embodiment, the thickness of the protective coating 20 is 0.2 μm to 0.4 μm. This ensures hydrophobic protection, preventing failure due to excessive thinness and wrinkling and peeling due to excessive thickness, while maintaining the overall thinness of the insulating layer, making it suitable for various electronic device usage scenarios.

[0074] In one embodiment, a transition layer is provided between the substrate layer 10 and the protective coating 20. The transition layer is a polyurethane transition layer. Polyurethane material has both adhesion and toughness, and has excellent compatibility with both the PET substrate and the protective coating 20. It fills the interface gap between the substrate and the protective coating 20, forming a seamless bonding layer, thereby improving the coating adhesion from the source.

[0075] Specifically, the thickness of the transition layer is 0.12μm to 0.22μm. This avoids insufficient interfacial bonding due to excessive thinness, while also preventing overall coating bulkiness and stress accumulation due to excessive thickness. This ensures that the buffering and bonding effects of the transition layer are maximized, without affecting the overall thinness of the insulation layer.

[0076] A composite material includes an insulating layer, an adhesive layer, a copper foil layer, and a conductive adhesive layer as described above. The adhesive layer is disposed between the insulating layer and the copper foil layer, and the conductive adhesive layer is disposed on the side of the copper foil layer away from the adhesive layer. The side of the conductive adhesive layer away from the copper foil layer is used to adhere and fix it to the screen surface. This composite material integrates an insulating layer, an adhesive layer, a copper foil layer, and a conductive adhesive layer, possessing multiple functions such as excellent fingerprint resistance, high surface wear resistance, insulation protection, conductivity, and screen adhesion. The insulating layer ensures that fingerprints are easily wiped away without residue and that it is wear-resistant and durable. The copper foil layer meets the conductivity requirements, the conductive adhesive layer can firmly adhere to the screen surface, and the adhesive layer ensures that the structure of each layer is tightly bonded and does not delaminate. The entire structure is adaptable to screen modules and other scenarios, is easy to install, has stable overall performance, and is highly practical.

[0077] Specifically, the adhesive layer is a polyurethane adhesive, and it also includes 4% to 6% by weight of black light-blocking pigment. The polyurethane adhesive possesses excellent bonding properties, ensuring tight adhesion between layers and improving interlayer bonding stability. The addition of the black light-blocking pigment enables the adhesive layer to have light-blocking functionality, filling the light-blocking gaps in the insulation layer, preventing light leakage at the interface, and further enhancing the overall light-blocking effect, while not affecting the adhesive properties of the polyurethane adhesive, thus balancing light blocking and bonding reliability.

[0078] A method for preparing an insulating layer, comprising the steps described above:

[0079] (1) The substrate layer 10 is subjected to surface cleaning, etching, washing and drying in sequence, and then subjected to micro-nano structure roughening treatment to obtain a rough surface with micron-sized protrusions 11 and nano-sized pits 12.

[0080] (2) Prepare the vapor deposition raw material for the protective coating 20 and pretreat the raw material;

[0081] (3) The substrate layer 10 after step (1) is placed in a vacuum evaporation equipment and the protective coating 20 is formed on its rough surface by vacuum evaporation process.

[0082] (4) After the base layer 10 is deposited, post-processing is performed to fix the protective coating 20 and obtain the insulating layer.

[0083] This preparation method ensures that the insulation layer performance meets the standards through a step-by-step process of pretreatment, micro-nano structure forming, vacuum evaporation coating, and post-treatment shaping: First, the substrate layer 10 is cleaned and etched to ensure that the micro-nano protrusions 11 and pits 12 are formed regularly and without impurities; the vacuum evaporation process allows the protective coating 20 to uniformly cover the micro-nano structure, with controllable coating thickness and tight bonding; the post-treatment process allows the coating to fully shape, further improving adhesion and wear resistance; the overall process has strong controllability and high yield, and the obtained insulation layer has stable anti-fingerprint and wear resistance properties, making it suitable for industrial mass production.

[0084] Specifically, in step (1), after cleaning the surface of the substrate layer 10, the micro-nano structure roughening process is completed by mask forming, micro-nano etching, mask removal and cleaning and drying in sequence, so as to obtain a rough surface with micron protrusions 11 and nano pits 12.

[0085] Masking can precisely define the arrangement, size, and spacing parameters of micron-sized protrusions 11 and nano-sized pits 12. The micro-nano etching process is highly controllable, allowing for precise control of the height of protrusions 11 and the aperture and depth of pits 12. The resulting micro-nano structures have high precision and excellent batch consistency. The etched micro-nano structures and the substrate layer 10 are homogeneous and integral, with high bonding strength and no risk of structural loosening or detachment. This provides a stable interface for the subsequent protective coating 20, further ensuring coating adhesion and surface wear resistance. The process allows for flexible adjustment of etching parameters to adapt to the needs of micro-nano structures of different specifications, resulting in an extremely low defect rate in the finished product structure.

[0086] Optionally, in step (1), after cleaning the surface of the substrate 10, it undergoes preheating and softening, micro-nano template pressing and shaping, demolding, and cleaning and drying to complete the roughening treatment of the micro-nano structure, thereby obtaining a rough surface with micron-sized protrusions 11 and nano-sized pits 12. Preheating and softening can make the substrate 10 plastic and easily moldable. Combined with micro-nano template pressing and shaping, the molding efficiency is high and the process cycle is short, making it more suitable for industrial mass production. This process is a physical molding method, without the problems of substrate loss and performance damage caused by chemical etching, and can completely preserve the original insulation, light-blocking rate and other basic characteristics of the substrate 10. The micro-nano template can be reused repeatedly, effectively reducing production costs. The demolding process is smooth and non-sticky. The protrusions 11 and pits 12 are complete in shape and uniformly arranged, which facilitates the uniform coating of the subsequent protective coating 20, ensuring stable anti-fingerprint performance and wear resistance.

[0087] The insulating layer provided by the present invention will be described below with reference to specific embodiments.

[0088] Example 1

[0089] 1. After cleaning the surface of the substrate layer 10, a micro-nano structure roughening process is performed to obtain a rough surface with an equivalent height H of 1.7 μm for the main protrusion, an equivalent diameter D of 1.0 μm at the bottom (H / D=1.7≥1.5), a spacing of 9 μm between adjacent main protrusions, and a maximum width of 62 nm for the pit 12. The surface is then cleaned and dried.

[0090] 2. Prepare and pretreat the raw materials for the protective coating 20 by vapor deposition. Place the substrate layer 10 in a vacuum vapor deposition equipment to vapor deposit a protective coating 20 with a thickness of 0.32 μm.

[0091] 3. An insulating layer is obtained after vacuum shaping.

[0092] It has excellent fingerprint resistance; pressing with the fingertip leaves no obvious fingerprint residue, and it can be completely cleaned with a light wipe. It has excellent coating adhesion; the cross-cut adhesion test shows no coating peeling off. It has excellent wiping resistance; after 500 repeated wipings, the coating surface shows no scratches or peeling.

[0093] Example 2

[0094] 1. After cleaning the surface of the substrate 10, a micro-nano structure roughening process was performed to obtain a rough surface with an equivalent height H of 1.8 μm for the main protrusion, an equivalent bottom diameter D of 1.1 μm (H / D≈1.64≥1.5), a spacing of 8 μm between adjacent main protrusions, and a maximum pit width of 57 nm. The surface was then cleaned and dried.

[0095] 2. Prepare and pretreat the raw materials for the protective coating 20 by vapor deposition. Place the substrate layer 10 in a vacuum vapor deposition equipment to vapor deposit a protective coating 20 with a thickness of 0.26 μm.

[0096] 3. An insulating layer is obtained after vacuum shaping.

[0097] It has excellent fingerprint resistance, leaving only very faint fingerprint marks that can be easily cleaned with a single wipe; the coating has excellent adhesion, remaining intact and undamaged in a cross-cut adhesion test; and it has excellent wiping resistance, showing no damage after 500 repeated wiping cycles.

[0098] Example 3

[0099] 1. After cleaning the surface of the substrate 10, a micro-nano structure roughening process was performed to obtain a rough surface with an equivalent height H of 1.6 μm for the main protrusion, an equivalent bottom diameter D of 0.9 μm (H / D≈1.78≥1.5), a spacing of 10 μm between adjacent main protrusions, and a maximum pit width of 68 nm. The surface was then cleaned and dried.

[0100] 2. Prepare and pretreat the raw materials for the protective coating 20 by vapor deposition. Place the substrate layer 10 in a vacuum vapor deposition equipment and vapor deposit a protective coating 20 with a thickness of 0.30 μm.

[0101] 3. An insulating layer is obtained after vacuum shaping.

[0102] It has excellent anti-fingerprint effect, leaving no fingerprint residue when pressed with the fingertip, and has a high degree of surface cleanliness; the coating has excellent adhesion, with no edge peeling or coating damage in the cross-cut test; and it has excellent wiping resistance, with the coating remaining intact after 600 repeated wiping cycles.

[0103] Example 4

[0104] 1. After cleaning the surface of the substrate 10, a micro-nano structure roughening process was performed to obtain a rough surface with an equivalent height H of 1.9 μm for the main protrusion, an equivalent bottom diameter D of 1.2 μm (H / D≈1.58≥1.5), a spacing of 7 μm between adjacent main protrusions, and a maximum pit width of 53 nm. The surface was then cleaned and dried.

[0105] 2. Prepare and pretreat the raw materials for the protective coating 20 by vapor deposition. Place the substrate layer 10 in a vacuum vapor deposition equipment and vapor deposit a protective coating 20 with a thickness of 0.23 μm.

[0106] 3. An insulating layer is obtained after vacuum shaping.

[0107] It has excellent anti-fingerprint effect, making it difficult for fingerprints to adhere, and the surface is smooth and clean; the coating has excellent adhesion, and the coating is firmly bonded to the base layer 10 in the cross-cut test; it has excellent wiping resistance, with no coating scratches or peeling after 500 repeated wiping cycles.

[0108] Example 5

[0109] 1. After cleaning the surface of the substrate 10, a micro-nano structure roughening process is performed to obtain a rough surface with an equivalent height H of 1.5 μm for the main protrusion, an equivalent bottom diameter D of 0.8 μm (H / D=1.875≥1.5), a spacing of 6 μm between adjacent main protrusions, and a maximum pit width of 76 nm. The surface is then cleaned and dried.

[0110] 2. Prepare and pretreat the raw materials for the protective coating 20 by vapor deposition. Place the substrate layer 10 in a vacuum vapor deposition equipment to vapor deposit a protective coating 20 with a thickness of 0.38 μm.

[0111] 3. An insulating layer is obtained after vacuum shaping.

[0112] It has excellent fingerprint resistance, leaving no residue when pressed with a fingertip and leaving no trace after wiping; the coating has excellent adhesion, with the entire coating remaining intact in the cross-cut adhesion test; and it has excellent wiping resistance, with no damage to the coating surface after 500 repeated wiping cycles.

[0113] Comparative Example 1

[0114] 1. Only surface cleaning, washing and drying were performed on the substrate layer 10, and no main protrusions and pit micro-nano structures were set;

[0115] 2. Prepare and pretreat the raw materials for the protective coating 20, and then vacuum evaporate to form a protective coating 20 with a thickness of 0.30μm;

[0116] 3. An insulating layer is obtained after vacuum shaping.

[0117] It has poor fingerprint resistance; fingerprints are clearly attached after pressing with the fingertip, and there are still obvious residues after multiple wipes. The coating adhesion is average; slight peeling of the coating edge was observed during the cross-cut adhesion test. The wiping resistance is average; after 280 wiping cycles, the coating showed minor scratches.

[0118] Comparative Example 2

[0119] 1. After cleaning the surface of the substrate 10, a micro-nano structure roughening process is performed to obtain a rough surface with an equivalent height H of 2.5 μm for the main protrusion, an equivalent bottom diameter D of 2.2 μm (H / D≈1.14<1.5), a spacing of 14 μm between adjacent main protrusions (>10 μm), and a maximum pit width of 90 nm (>80 nm). The surface is then cleaned and dried.

[0120] 2. Prepare and pretreat the raw materials for the protective coating 20, and then vacuum evaporate to form a protective coating 20 with a thickness of 0.45μm;

[0121] 3. An insulating layer is obtained after vacuum shaping.

[0122] The anti-fingerprint effect is uneven, with fingerprints easily adhering to certain areas and difficult to wipe off; the coating adhesion is poor, with multiple areas of coating peeling off during the cross-cut test, and the coating warping at the tip of the raised 11; the wiping resistance is poor, with obvious scratches and large pieces of coating peeling off after 190 repeated wiping cycles.

[0123] In summary, all five embodiments, through the synergistic cooperation of the micro-nano structure on the surface of the substrate layer 10 and the protective coating 20, have achieved the core technical effects of reducing the fingerprint adhesion area using the micro-nano structure, enhancing the hydrophobic effect of the protective coating 20, making fingerprints easy to wipe away without residue, and effectively improving the wear resistance of the insulating layer surface. The performance of each embodiment fluctuates slightly only due to the random differences in the core parameters of the micro-nano structure and the protective coating 20, and all can meet the actual use requirements of the product. However, the two sets of comparative embodiments either lack the core structure of the micro-nano structure rough treatment, or the parameters of the micro-nano structure and the protective coating 20 exceed the limits of this invention, resulting in a significant reduction in the anti-fingerprint effect, hydrophobicity and easy wiping, and surface wear resistance, which cannot meet the product use standards. This fully demonstrates the inventiveness and practicality of the technical solution of this invention.

[0124] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0125] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. An insulating layer, characterized in that, It includes a base layer and a protective coating; the protective coating is applied to the base layer, and the surface of the base layer coated with the protective coating has protrusions and pits. The protrusions include multiple main protrusions, and the ratio of the equivalent height H of the main protrusions to the equivalent bottom diameter D is H / D≥1.

5. The spacing between adjacent main protrusions is 5μm to 10μm. The maximum width of the pits is 50nm to 80nm.

2. The insulating layer according to claim 1, characterized in that, The cross-sectional width of the main protrusion decreases continuously along its height, and the ratio W1 / D of the equivalent width W1 of the main protrusion at half its height to the equivalent diameter D at the bottom is 0.4 to 0.7; and / or The angle β between the sidewall of the main protrusion and the surface of the base layer is 70° to 85°; and / or The top of the main protrusion is hemispherical or arc-shaped, with a radius of curvature R of 0.3μm to 0.8μm.

3. The insulating layer according to claim 2, characterized in that, The upper third of the main protrusion has micro-protrusions, which are distributed on the top end face and sidewalls of the main protrusion; the height h of the micro-protrusions is 0.1 μm to 0.5 μm, and the bottom width w of the micro-protrusions is 0.2 μm to 0.8 μm; and / or The angle β1 between the tangent of the sidewall of the main protrusion at 1 / 3 of its height and the surface of the base layer is 75° to 88°.

4. The insulating layer according to claim 1, characterized in that, At least 70% of the main protrusions have a height H of 1.5 μm to 4.5 μm and a bottom equivalent diameter D of 0.8 μm to 2.5 μm; and / or The center-to-center distance between adjacent pits is 100 nm to 200 nm; and / or The depth of the pit is 30nm to 60nm.

5. The insulating layer according to claim 1, characterized in that, The pits are distributed in the gap region between adjacent main protrusions, and the inner wall of the pit is not directly connected to the side wall of the main protrusion; and / or The minimum distance between the edge of the recess and the main protrusion is 0.8 μm to 1.5 μm; and / or The ratio of the depth h of the pit to the height H of the main protrusion is h / H≤0.

04.

6. The insulating layer according to claim 1, characterized in that, The surface roughness Ra of the base layer having the main protrusion and the pit is 0.12μm to 0.25μm, and the arithmetic mean deviation of the profile Rz is 0.6μm to 1.2μm.

7. The insulating layer according to any one of claims 1-6, characterized in that, The distribution density of the pits per unit area on the substrate coating surface is 8 × 10⁻⁶. 5 pcs / cm²~3×10 6 pcs / cm²; and / or The distribution density of the main protrusions is 5×10⁻⁶. 4 Units / cm²~2×10 5 pcs / cm² 8. The insulating layer according to any one of claims 1-6, characterized in that, The protective coating has a thickness of 0.2μm to 0.3μm on the top of the main protrusion and a thickness of 0.3μm to 0.4μm on the bottom of the pit, with a coating thickness difference of ≤0.2μm between the protrusion and the pit. and / or The protective coating is any one of a perfluoropolyether coating, a perfluorooctyltriethoxysilane coating, or a fluorinated acrylate coating; and / or The thickness of the protective coating is 0.2μm to 0.4μm.

9. A composite material, characterized in that, It includes an insulating layer, an adhesive layer, a copper foil layer, and a conductive adhesive layer as described in any one of claims 1-8; the adhesive layer is disposed between the insulating layer and the copper foil layer, and the conductive adhesive layer is disposed on the side of the copper foil layer away from the adhesive layer, the side of the conductive adhesive layer away from the copper foil layer being used to adhere and fix it to the screen surface.

10. A method for preparing an insulating layer, used to prepare the insulating layer according to any one of claims 1-8, characterized in that, The method for preparing the insulating layer includes the following steps: (1) The substrate layer is subjected to surface cleaning, etching, washing and drying in sequence, and then subjected to micro-nano structure roughening treatment to obtain a rough surface with micron-scale protrusions and nano-scale pits. (2) Prepare the vapor deposition raw material for the protective coating and pretreat the raw material; (3) The substrate layer after step (1) is placed in a vacuum evaporation equipment and the protective coating is formed on its rough surface by vacuum evaporation process. (4) After the base layer is deposited by vapor deposition, post-processing is performed to fix the protective coating and obtain the insulating layer.

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