Composite nail plate and method of manufacturing the same

Abstract

The present invention relates to a composite nail piece and its manufacturing method, having an inner end and an outer end oppositely arranged along its longitudinal direction, the composite nail piece comprising: a polymer inner lining layer-stacked connected to the inner side of a metal shell, and used to extend along the longitudinal direction from the inner end and cover at least a part of a natural nail, the inner side of the polymer inner lining away from the metal shell constituting a contact surface with the natural nail, the section of the metal shell covered by the polymer inner lining being a contact section, and the section of the composite nail piece between the contact section and the outer end constituting an extension section; in the contact section, along the direction from the junction of the contact section and the extension section to the inner end, the thickness of the metal shell presents a decreasing trend, and the thickness of the polymer inner lining presents an increasing trend, and the maximum thickness of the metal shell is located at the junction or its adjacent area. The metal shell is thinned in the inner end area of the contact section to be elastically deformed to fit any C-arc; the polymer inner lining is thickened in the inner end area to make up the total thickness and fill the difference in curvature between the nail piece and the natural nail.

Description

Technical Field

[0001] This invention relates to the technical field of nail products, and more particularly to a composite nail tip and its manufacturing method. Background Technology

[0002] As living standards continue to improve, people's pursuit of quality of life is also constantly increasing. Nail art has become a popular choice for enhancing personal appearance and bringing joy to oneself and others. Currently, common nail extensions are typically made from single polymer or metal materials, but this presents several challenges, hindering the development of the nail art industry and impacting user experience and satisfaction.

[0003] Specifically, the rigidity of a single polymer material nail tip is generally consistent across the entire tip. To ensure the cantilever section is not easily broken, the tip must have sufficient thickness and rigidity; however, this rigidity also exists in the inner end area of ​​the fitting section, making it impossible for the tip to effectively conform to the significantly different lateral curvature (C-curve) of the natural nail surface of different users. The consequence is gaps appearing between the sides of the tip and the natural nail, leading to water ingress, easy lifting, short wearing time, and the edges pressing against the skin in the nail groove. At this point, manufacturers can only alleviate the problem by increasing the number of sizes, but this still cannot cover the differences in curvature.

[0004] The thermal conductivity of metal nail tips is approximately 100 to 800 times that of polymer materials, and they also have a high heat capacity. When metal nail tips are directly attached to natural nails, the dense distribution of blood vessels and nerve endings in the nail bed beneath the natural nail causes heat to be conducted through the metal tip to the nail bed. This results in a noticeable cold, stinging sensation in low-temperature environments and a burning sensation when in contact with a heat source, making metal nail tips practically unsuitable for everyday wear. Furthermore, the elastic modulus of metal is more than 80 times that of polymer materials. Users cannot trim them with a nail file like with plastic nail tips, nor can they adjust the C-curve by pinching them together. This easily leads to size and curvature mismatches, making them unwearable. Therefore, current metal nail tips can only be produced through one-to-one customization (3D scanning + additive manufacturing), and cannot be mass-produced. Summary of the Invention

[0005] The purpose of this invention is to provide a composite nail plate and its manufacturing method, which solves the problems that cold and burning sensations affect wearing comfort and experience, and that rigidity and bending resistance cannot be balanced with wearing fit.

[0006] According to one aspect of the present invention, a composite armor plate is provided having inner ends and outer ends disposed opposite to each other along its longitudinal direction, the composite armor plate comprising: a metal outer shell and a polymer inner liner; The outer surface of the metal shell constitutes the appearance finish of the composite nail plate. The polymer liner is stacked and connected to the inner side of the metal shell and extends longitudinally from the inner end to cover at least a portion of the natural nail. The inner side of the polymer liner away from the metal shell constitutes the bonding surface that contacts the natural nail. The section of the metal shell covered by the polymer liner is the bonding section. The section of the composite nail plate located between the bonding section and the outer end constitutes the extension section. Within the bonding section, along the direction from the junction of the bonding section and the extension section toward the inner end, the thickness of the metal outer shell tends to decrease, while the thickness of the polymer inner liner tends to increase, and the portion of the metal outer shell with the maximum thickness is located at or near the junction.

[0007] In one embodiment, the inner side of the metal shell is provided with a bonding interface, and the metal shell is bonded and fixed to the polymer liner through the bonding interface.

[0008] In one embodiment, the bonding interface is a rough structure formed by sandblasting or micro-etching.

[0009] In one embodiment, the bonding interface is a first snap-fit ​​portion that protrudes or is recessed on the inner side of the metal shell, and the polymer liner is recessed or protruded on the bonding surface facing the metal shell, forming a second snap-fit ​​portion, which is engaged and fixed with the first snap-fit ​​portion.

[0010] In one embodiment, the elastic modulus ratio of the metal outer shell to the polymer liner is: E1 / E2≥10.

[0011] In one embodiment, the thickness of the metal casing at the inner end is set as t1, and the maximum thickness of the metal casing is set as t2, wherein: 1 <t2 / t1≤ 8。

[0012] In one embodiment, the thickness of the metal casing ranges from 0.01mm to 8mm; wherein 0.01mm ≤ t1 <t2≤8mm。

[0013] In one embodiment, the length of the bonding segment ranges from 2mm to 16mm.

[0014] In one embodiment, the thickness of the polymer liner at the inner end ranges from 0.1 mm to 3 mm.

[0015] In one embodiment, the composite armor plate includes: a metal outer shell and a polymer inner liner; The outer surface of the metal shell constitutes the appearance finish of the composite nail plate. The polymer liner is stacked and connected to the inner side of the metal shell and extends longitudinally from the inner end to cover at least a portion of the natural nail. The inner side of the polymer liner away from the metal shell constitutes the bonding surface that contacts the natural nail. The section of the metal shell covered by the polymer liner is the bonding section. The section of the composite nail plate located between the bonding section and the outer end constitutes the extension section. Within the bonding section, along the direction from the junction of the bonding section and the extension section toward the inner end, the metal shell has a uniform wall thickness, and the wall thickness of the metal shell is basically consistent at each part along its extension direction.

[0016] According to another aspect of the present invention, a method for manufacturing composite nail plates is also provided, which is applicable to processing composite nail plates as described in any of the above embodiments. The method for manufacturing composite nail plates includes the following steps: Prepare metal coils and process them to obtain flat metal blanks; The metal blank is bent to obtain a metal shell with a hyperboloid structure that meets the longitudinal curvature and the lateral curvature of the front surface; The metal shell is locally thinned corresponding to the bonding section so that the metal shell has a thickness distribution that decreases from the junction to the inner end; Repair and finish the metal casing; The metal shell is placed in the molding space, and then a polymer material is loaded into the molding space and the polymer material is cured or molded to obtain a polymer liner that is layered and connected to the inside of the metal shell. Demolding process yields a composite armor plate with a layered structure of metal shell and polymer liner.

[0017] Implementing the embodiments of the present invention will have the following beneficial effects: This composite nail tip is worn over the user's natural nail. It has a longitudinal direction consistent with the length of the finger, an inner end close to the nail root, and an outer end further away from the nail root. Specifically, the composite nail tip has a double-layer structure consisting of a metal shell and a polymer inner liner. The outer surface of the metal shell forms the surface finish of the composite nail tip, ensuring its aesthetics and visual appeal. The polymer inner liner extends longitudinally from the inner end, covering at least a portion of the natural nail. The section of the metal shell covered by the polymer inner liner is the bonding section, and the section of the composite nail tip between the bonding section and the outer end is the extension section. Furthermore, this design defines the dimensions and shapes of the metal shell and the polymer inner liner. Within the bonding section, the thickness of the metal shell decreases along the direction from the junction of the bonding section and the extension section towards the inner end, while the thickness of the polymer inner liner increases. The maximum thickness of the metal shell is located at or near the junction. The adjacent area refers to the region extending longitudinally no more than 20% of the length of the bonding section from the junction. In this way, on the one hand, because the polymer liner is thickest at the inner end of the bonding section (i.e., the area with the largest contact area with the deck and the most significant heat exchange), it forms a thermal resistance layer between the metal shell and the natural armor, effectively blocking heat flow from the metal shell to the natural armor bed, eliminating cold stinging and burning sensations. On the other hand, utilizing the principle that the lateral bending stiffness of a plate is proportional to the product of its elastic modulus and thickness, since the elastic modulus of the metal shell is much higher than that of the polymer liner (approximately 50 to 100 times higher), the bending stiffness of the composite armor plate is almost entirely determined by the local thickness of the metal shell. Therefore, the metal shell thins at the inner end of the bonding section, causing the lateral bending stiffness in that area to decrease sharply according to the cube of its thickness, thus allowing elastic deformation to conform to any C-curve. At the junction (the root of the cantilever, where the bending moment is greatest), the metal shell is thickest, maintaining sufficient stiffness to resist breakage. The polymer liner is thickened in the inner end area to make up for the total thickness and fill the curvature difference between the nail plate and the natural nail. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0019] Figure 1 This is a schematic diagram of the structure of a composite armor plate according to one embodiment; Figure 2 This is an exploded structural diagram of the composite armor plate; Figure 3 This is a schematic diagram of the cross-sectional structure of the composite armor plate; Figure 4 This is a flowchart illustrating the steps of a method for manufacturing a composite armor plate according to one embodiment.

[0020] in: 100. Composite nail plate; 110. Inner end; 120. Outer end; 10. Metal shell; 11. Exterior finish; 20. Polymer liner; 21. Adhesive surface; 30. Bonding interface. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0022] It should be noted that when a component is said to be "fixed to" another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this document are for illustrative purposes only.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0024] In the current technology, nail art is a relatively common way for people to beautify themselves. Nail tips are usually made of a single polymer material or plastic material, but this will bring some problems, which restrict the development of the nail art industry and the user experience and satisfaction.

[0025] Specifically, the rigidity of nail tips made of a single polymer material is basically uniform across the entire piece. To ensure the cantilever section is not easily broken, the nail tip must have sufficient thickness and rigidity; however, this rigidity also exists in the inner 110 zone of the bonding section, making it impossible for the nail tip to effectively conform to the significantly different lateral curvature (C-curve) of the natural nail surface of different users. The consequence is gaps appearing between the sides of the nail tip and the natural nail, leading to water ingress, easy lifting, short wearing time, and pressure on the skin in the nail groove from the edges. At this point, manufacturers can only alleviate the problem by increasing the number of sizes, but this still cannot cover the curvature differences. Nail tips made of a single metal material have a thermal conductivity approximately 100 to 800 times that of polymer materials, and a large heat capacity. When a metal nail tip is directly attached to the natural nail, due to the dense distribution of blood vessels and nerve endings in the nail bed beneath the natural nail, heat is conducted through the metal tip to the nail bed, resulting in a noticeable cold stinging sensation in low-temperature environments and a burning sensation when in contact with a heat source, effectively making metal nail tips difficult to wear daily. In addition, the elastic modulus of metal is more than 80 times that of polymer materials. Users cannot trim it with a nail file like plastic nail plates, nor can they adjust its C-curve by pinching it. This easily leads to a mismatch between size and curvature, making it unwearable. Therefore, existing metal nail plates can only follow a one-to-one customization route (3D scanning + additive manufacturing) and cannot be mass-produced.

[0026] To address the aforementioned issues, this application proposes a novel nail tip design that effectively resolves these problems and shortcomings, providing users with a better nail art experience. Please see details. Figures 1-3 The composite armor plate 100 described in one embodiment has an inner end 110 and an outer end 120 disposed opposite to each other along its longitudinal direction. The composite armor plate 100 includes a metal shell 10 and a polymer liner 20.

[0027] The outer surface of the metal shell 10 constitutes the appearance finish 11 of the composite armor plate 100. It should be noted that the appearance finish 11 of the metal shell 10 can be the metallic color and luster of the metal shell 10 itself, or it can be a special pattern or design formed by design and processing, or it can be a decorative part that is additionally installed on the outer surface, which can be selected as needed.

[0028] The material of the metal casing 10 may be, but is not limited to, titanium, stainless steel, aluminum alloy, copper alloy, precious metal, or nickel-titanium shape memory alloy (superelastic NiTi).

[0029] For example, titanium has advantages such as being nickel-free, having good biocompatibility, and being able to be anodized to form structural colors. Stainless steel has advantages such as low cost, corrosion resistance, low nickel release, and a mature supply chain. Superelastic NiTi, or nickel-titanium alloy (NiTi or Nitinol for short), is a special metallic material that combines superelasticity and shape memory effects. It is widely used in medical devices, aerospace, and consumer electronics. Superelastic NiTi enables composite armor plates to achieve an elastic clamping effect after installation, balancing installation stability and comfort.

[0030] The polymer liner 20 is laminated and connected to the inside of the metal shell 10, and is used to extend longitudinally from the inner end 110 and cover at least a portion of the natural nail. The inner side of the polymer liner 20 away from the metal shell 10 forms the bonding surface 21 that contacts the natural nail. The section of the metal shell 10 covered by the polymer liner 20 is the bonding section, and the section of the composite nail plate 100 located between the bonding section and the outer end 120 forms the extension section.

[0031] The specific bonding section is as follows Figure 3 The line segment of S1; the extension segment is specifically as follows Figure 3 The line segment part of S2.

[0032] The material of the polymer liner 20 can be, but is not limited to, UV-curable resin, TPU, TPE, silicone or hydrogel.

[0033] For example, the UV-curing resin specifically uses aliphatic polyurethane acrylate UV-curing resin, which is homologous to nail glue and nail polish, has good adhesion, and facilitates adjustment of elastic modulus.

[0034] Within the bonding section, along the direction from the junction of the bonding section and the extension section toward the inner end 110, the thickness of the metal shell 10 tends to decrease, while the thickness of the polymer liner 20 tends to increase, and the part with the maximum thickness of the metal shell 10 is located at or near the junction.

[0035] It should be noted that the total thickness of the metal outer shell 10 and the polymer inner liner 20 is basically constant or varies by less than 30% along the bonding section, so as to ensure the comprehensive performance of the composite armor plate 100, such as wearing comfort and sufficient rigidity.

[0036] It should also be noted that, given that the bending moment of the cantilever beam decreases linearly from the root to the free end along the cantilever, approaching zero at the free end, this application sets the maximum thickness of the metal shell 10 at the root of the cantilever (i.e., the junction), rather than at the outer end 120. This allows the invention to cover nail plates of any length, including artistic nails with an extension section much longer than the fitting section.

[0037] Implementing the embodiments of the present invention will have the following beneficial effects: The composite nail plate 100 of this solution is worn on the natural nail of the user's finger. The composite nail plate 100 has a longitudinal direction consistent with the length of the finger, and an inner end 110 close to the nail root of the natural nail and an outer end 120 away from the nail root. Specifically, the composite nail plate 100 has a double-layer structure composed of a metal shell 10 and a polymer inner liner 20. The outer surface of the metal shell 10 constitutes the appearance surface of the composite nail plate 100 to ensure the aesthetics and visual experience of the composite nail plate 100. The polymer inner liner 20 extends longitudinally from the inner end 110 to cover at least a portion of the natural nail. The section of the metal shell 10 covered by the polymer inner liner 20 is the fitting section, and the section of the composite nail plate 100 between the fitting section and the outer end 120 constitutes the extension section. Based on this, this solution further defines the dimensions and shapes of the metal shell 10 and the polymer liner 20. Specifically, within the bonding section, along the direction from the junction of the bonding section and the extension section towards the inner end 110, the thickness of the metal shell 10 tends to decrease, while the thickness of the polymer liner 20 tends to increase. Furthermore, the area of ​​maximum thickness of the metal shell 10 is located at or near the junction. The adjacent area refers to the region extending longitudinally from the junction at no more than 20% of the length of the bonding section.

[0038] In this way, on the one hand, since the polymer liner 20 has the largest thickness in the inner end 110 region of the bonding section (i.e., the region with the largest contact area with the deck and the most important heat exchange), it forms a thermal resistance layer between the metal shell 10 and the natural armor, effectively blocking the heat flow from the metal shell 10 to the armor bed of the natural armor and eliminating the cold stinging and burning sensations; on the other hand, by taking advantage of the principle that the lateral bending stiffness of the plate is proportional to the product of its material elastic modulus and thickness, since the elastic modulus of the metal shell 10 is much higher than that of the polymer liner 20 (about 50 to 100 times or more), the bending stiffness of the composite armor plate 100 is almost entirely determined by the local thickness of the metal shell 10. Therefore, the metal shell 10 is thinned in the inner end 110 region of the bonding section, causing the lateral bending stiffness of this region to drop sharply according to the cube of the thickness, so that it can elastically deform to fit any C-arc; while at the junction (the root of the cantilever, the place with the largest bending moment), the metal shell 10 is the thickest, maintaining sufficient stiffness to resist breakage. The polymer liner 20 is thickened in the inner end 110 area to make up for the total thickness and fill the curvature difference between the nail plate and the natural nail.

[0039] Please see Figure 3Furthermore, in one embodiment, the inner surface of the metal shell 10 is provided with a bonding interface 30, through which the metal shell 10 is bonded and fixed to the polymer liner 20. This bonding interface 30 connects the metal shell 10 and the polymer liner 20 as a single unit, significantly improving the bonding strength and peel resistance between the metal shell 10 and the polymer liner 20, preventing separation that could affect the lifespan of the composite shell 100 and the user experience.

[0040] It should be noted that the interface 30 can be a local area formed on the inner side of the metal shell 10, or it can be the entire area covering the inner side, whichever is required.

[0041] For example, in one embodiment, the bonding interface 30 is a rough structure formed by sandblasting or micro-etching. Since the polymer liner 20 is usually injection molded and cured from a fluid material, setting the bonding interface 30 to a rough structure can increase the bonding area with the fluid material, thereby improving the bonding force between the metal shell 10 and the polymer liner 20, ensuring high connection strength and stable reliability.

[0042] It should be noted that when a rough structure uses a concave hole structure, the shape, diameter, and other parameters of the multiple concave holes can be the same or different. Similarly, when a rough structure uses a convex structure, the shape, height, diameter, and other parameters of the multiple convex protrusions can be the same or different. These can be selected as needed, and no specific restrictions are imposed here.

[0043] Alternatively, in another embodiment, the interface 30 is a first snap-fit ​​portion protruding or recessed on the inner side of the metal shell 10, and the polymer liner 20 is recessed or protruding on the interface facing the metal shell 10 with a second snap-fit ​​portion, which is fastened and fixed to the first snap-fit ​​portion. By means of the physical fastening connection formed by the first and second snap-fit ​​portions, a locking force can be generated to reinforce the connection between the metal shell 10 and the polymer liner 20, improving their anti-peel properties and increasing the durability and service life of the composite shell 100.

[0044] For example, the first snap-fit ​​part is the first hook body, and the second snap-fit ​​part is the second hook body. The first hook body can be hooked and connected with the second hook body to provide sufficient and reliable bonding force between the metal shell 10 and the polymer liner 20.

[0045] In one embodiment, the ratio of the elastic modulus of the metal outer shell 10 to that of the polymer inner liner 20 is: E1 / E2≥10. More preferably, E1 / E2≥20. In this way, the metal outer shell 10 can not only obtain sufficient rigidity to resist breakage, but also have excellent elastic deformability, so as to fit the natural nail with any size of transverse radian of the nail surface together with the polymer inner liner 20. In addition, the polymer inner liner 20 is enabled to have excellent elasticity to fit the natural nail, avoiding poor fitting that causes gaps between the liner and the natural nail, leading to problems such as water ingress and easy edge lifting.

[0046] In one embodiment, the thickness of the metal outer shell 10 at the inner end 110 is set as t1, and the maximum thickness of the metal outer shell 10 is set as t2, where: 1<t2 / t1≤8. The inner end 110 region of the metal outer shell 10 at the fitting section is thinned, so that the transverse bending rigidity of this region drops sharply according to the cube of the thickness, thus enabling elastic deformation to fit any C-curve; while at the junction (the root of the cantilever, where the bending moment is maximum), the metal outer shell 10 is the thickest to maintain sufficient rigidity to resist breakage.

[0047] For example, the thickness range of the metal outer shell 10 is: 0.01mm-8mm; where 0.01mm≤t1<t2≤8mm. In this way, the metal outer shell 10 can be provided with high structural strength and strong bending resistance, while ensuring that the partial thickness of the fitting section is not excessively large, and has excellent elastic deformability, so as to closely and effectively fit the natural nail together with the polymer inner liner 20.

[0048] It should be noted that in other alternative embodiments, t1 can also be equal to t2, that is, the thickness of the metal outer shell 10 does not change, the metal outer shell 10 has a uniform wall thickness, and the wall thickness of each part of the metal outer shell 10 along its extending direction is basically consistent. In some embodiments, the metal outer shell 10 is in a planar shape, and the side of the metal outer shell 10 facing the nail is provided with the polymer inner liner 20. Specifically, the metal outer shell 10 is a plane with a thickness approximate to that of paper, and the outer end 120 of the metal outer shell 10 is bent inward toward the direction of the nail gap, with the bent part transitioning smoothly, so as to prevent the metal outer shell 10 from scratching people due to being too thin.

[0049] In one embodiment, the length of the fitting section ranges from 2mm to 16mm. Limiting the length of the fitting section to the above numerical range can not only effectively cover the length of common natural nails, but also further meet the installation requirements of special nail types such as artistic long nails, greatly expanding the applicable range of the composite nail piece 100.

[0050] In one embodiment, the thickness of the polymer liner 20 at the inner end 110 ranges from 0.1 mm to 3 mm. This allows the polymer liner 20 near the nail bed to have a sufficiently large thickness to block heat transfer to the nail bed, thereby effectively eliminating cold, stinging, and burning sensations.

[0051] Please see Figure 4 According to another aspect of the present invention, a method for manufacturing a composite armor plate 100 is also provided, which is applicable to processing the composite armor plate 100 as described in any of the above embodiments. The method for manufacturing the composite armor plate 100 includes the following steps: S10: Prepare metal coils and process them to obtain flat metal blanks.

[0052] For example, processing methods for metal coils can include photochemical etching, laser cutting, etc. The resulting metal blank is actually a rectangular metal sheet.

[0053] S20: The metal blank is bent to obtain a metal shell 10 with a hyperboloid structure that meets the longitudinal curvature and the transverse curvature of the front surface.

[0054] The bending process for metal blanks can be carried out by methods such as soft film (such as rubber bladder) forming and hydroforming.

[0055] S30: The metal shell 10 is locally thinned corresponding to the bonding section so that the metal shell 10 forms a thickness distribution that decreases from the junction to the inner end 110.

[0056] S40: Perform finishing treatment on the metal casing 10.

[0057] Specifically, the edges of the metal casing 10 are deburred, polished, and surface-treated.

[0058] S50: Place the metal shell 10 in the molding space, then fill the molding space with polymer material, and allow the polymer material to solidify or be molded to obtain a polymer liner 20 that is laminated and connected to the inside of the metal shell.

[0059] For example, the molding space can refer to, but is not limited to, the mold cavity of a mold. The polymer material can be, but is not limited to, UV-curable resins.

[0060] S60: Demolding process to obtain a composite armor plate 100 with a layered structure of metal shell 10 and polymer liner 20.

[0061] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. 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 scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A composite armor plate, having inner ends and outer ends disposed opposite each other along its longitudinal direction, characterized in that, The composite armor plate comprises: a metal outer shell and a polymer inner liner; The outer surface of the metal shell constitutes the appearance finish of the composite nail plate. The polymer liner is stacked and connected to the inner side of the metal shell and extends longitudinally from the inner end to cover at least a portion of the natural nail. The inner side of the polymer liner away from the metal shell constitutes the bonding surface that contacts the natural nail. The section of the metal shell covered by the polymer liner is the bonding section. The section of the composite nail plate located between the bonding section and the outer end constitutes the extension section. Within the bonding section, along the direction from the junction of the bonding section and the extension section toward the inner end, the thickness of the metal outer shell tends to decrease, while the thickness of the polymer inner liner tends to increase, and the portion of the metal outer shell with the maximum thickness is located at or near the junction.

2. The composite armor plate according to claim 1, characterized in that, The inner surface of the metal shell is provided with a bonding interface, through which the metal shell is bonded and fixed to the polymer liner.

3. The composite armor plate according to claim 2, characterized in that, The bonding interface is a rough structure formed by sandblasting or micro-etching.

4. The composite armor plate according to claim 2, characterized in that, The bonding interface is a first snap-fit ​​portion that is protruding or recessed on the inner side of the metal shell, and the polymer liner is recessed or protruding on the bonding surface facing the metal shell, forming a second snap-fit ​​portion, which is fastened and fixed to the first snap-fit ​​portion.

5. The composite armor plate according to claim 1, characterized in that, The elastic modulus ratio of the metal outer shell to the polymer inner liner is: E1 / E2 ≥ 10.

6. The composite armor plate according to claim 1, characterized in that, The thickness of the metal casing at the inner end is denoted as t1, and the maximum thickness of the metal casing is denoted as t2, wherein: 1 <t2 / t1≤ 8。 7. The composite armor plate according to claim 6, characterized in that, The thickness of the metal casing ranges from 0.01mm to 8mm; where 0.01mm ≤ t1 < t2 ≤ 8mm.

8. The composite armor plate according to claim 1, characterized in that, The length of the bonding section ranges from 2mm to 16mm; or the thickness of the polymer liner at the inner end ranges from 0.1mm to 3mm.

9. A composite armor plate having inner ends and outer ends disposed opposite each other along its longitudinal direction, characterized in that, The composite armor plate comprises: a metal outer shell and a polymer inner liner; The outer surface of the metal shell constitutes the appearance finish of the composite nail plate. The polymer liner is stacked and connected to the inner side of the metal shell and extends longitudinally from the inner end to cover at least a portion of the natural nail. The inner side of the polymer liner away from the metal shell constitutes the bonding surface that contacts the natural nail. The section of the metal shell covered by the polymer liner is the bonding section. The section of the composite nail plate located between the bonding section and the outer end constitutes the extension section. Within the bonding section, along the direction from the junction of the bonding section and the extension section toward the inner end, the metal shell has a uniform wall thickness, and the wall thickness of the metal shell is basically consistent at each part along its extension direction.

10. A method for manufacturing a composite armor plate, characterized in that, The manufacturing method is applicable to the processing of the composite armor plate as described in claim 1, and includes the following steps: Prepare metal coils and process them to obtain flat metal blanks; The metal blank is bent to obtain a metal shell with a hyperboloid structure that meets the longitudinal curvature and the lateral curvature of the front surface; The metal shell is locally thinned corresponding to the bonding section so that the metal shell has a thickness distribution that decreases from the junction to the inner end; Repair and finish the metal casing; The metal shell is placed in the molding space, and then a polymer material is loaded into the molding space and the polymer material is cured or molded to obtain a polymer liner that is layered and connected to the inside of the metal shell. Demolding process yields a composite armor plate with a layered structure of metal shell and polymer liner.

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