Aluminum-plastic combined body processing method and aluminum-plastic combined body

Abstract

The aluminum-plastic combined body machining method comprises the following steps that an aluminum piece is provided, the aluminum piece comprises a first end portion, a second end portion and a middle portion, the sectional area of the middle portion is larger than that of the first end portion and that of the second end portion, and sawtooth areas are arranged on the peripheries of the first end portion and the second end portion; and glue is provided, and the sawtooth areas of the first end part and the second end part are evenly coated with the glue. The method has the beneficial effects that a plurality of circumferential sawtooth grooves are cut in the periphery of the end part of the aluminum part raw material at intervals to form a sawtooth area with a certain width, the sawtooth area is coated with glue and naturally aired and cured to form solid glue, and the end part of the aluminum part is put into an injection molding machine; the injection molding machine performs thermosetting molding on the injection molding material, the solid glue and the end part of the aluminum piece by utilizing high temperature and pressure, and then the aluminum-plastic combination body is formed after standing and cooling, and the glue is uniformly distributed in the sawtooth area, so that the connection strength between the aluminum piece and the plastic piece of the aluminum-plastic combination body is improved.

Description

Technical Field

[0001] This invention belongs to the field of aluminum-plastic composite processing technology, and particularly relates to an aluminum-plastic composite processing method and an aluminum-plastic composite. Background Technology

[0002] Liquid cooling plates are heat dissipation components in industrial equipment. They are designed with internal flow channels that utilize the circulating flow of coolant to remove heat generated during equipment operation, thus maintaining a stable internal temperature. Harmonica tube type liquid cooling plates are a common type, typically made from extruded aluminum profiles. They feature a simple and lightweight structure, a regular internal flow channel layout, low coolant flow resistance, good heat dissipation uniformity, and high applicability.

[0003] The harmonica tube type liquid cooling plate is an aluminum-plastic composite, consisting of a long strip of aluminum and plastic parts at both ends of the aluminum. During use, the liquid cooling plate is subjected to frequent hot and cold cycles, causing the aluminum shell to repeatedly expand outward or contract inward. Therefore, sufficient bonding force is required between the aluminum and plastic parts.

[0004] In existing aluminum-plastic composite processing, the ends of the aluminum raw materials are usually directly injection molded, and the resulting plastic part is thermoset with the aluminum shell. The aluminum-plastic composite produced in this way has low connection strength between the aluminum and plastic parts, which cannot meet the application scenarios with high requirements for bonding strength between aluminum and plastic. Therefore, a production process that can improve the pull-out force and airtightness of aluminum-plastic composites is needed. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a processing method and an aluminum-plastic composite, which can improve the bonding force between aluminum parts and plastic parts.

[0006] To achieve the above objectives, the present invention employs the following technical solution: a method for processing an aluminum-plastic composite, comprising the following steps: providing an aluminum part, the aluminum part including a first end, a second end, and a middle part, wherein the cross-sectional area of ​​the middle part is larger than the cross-sectional area of ​​the first end and the second end, and serrated areas are provided on the outer periphery of both the first end and the second end; providing adhesive, uniformly applying the adhesive to the serrated areas of the first end and the second end, allowing it to stand at room temperature for the adhesive to dry and cure, forming a solid adhesive; providing injection molding material and an injection molding machine, placing the injection molding material into the injection molding machine, placing the first end after applying the adhesive into the injection molding machine, the injection molding machine processing the injection molding material into a first injection molded body, and thermosetting the first injection molded body, adhesive, and the first end; then placing the second end after applying the adhesive into the injection molding machine, the injection molding machine processing the injection molding material into a second injection molded body, and thermosetting the second injection molded body, adhesive, and the second end; finally, allowing the injection-molded aluminum part to stand and cool to form an aluminum-plastic composite.

[0007] Optionally, providing the aluminum part includes the following steps: providing aluminum raw material, the aluminum raw material including a shell, the shell having a cavity, the shell including two oppositely arranged straight portions and two oppositely arranged arc portions, and a plurality of connecting portions between the two straight portions; providing a necking mold, placing both ends of the aluminum raw material into the necking mold in sequence for punching and necking to form a first end and a second end, and forming an intermediate portion between the first end and the second end; providing a laser cutting machine, placing the first end into the laser cutting machine, and cutting a plurality of circumferential sawtooth grooves along the outer surface of the first end, the plurality of circumferential sawtooth grooves being evenly spaced along the length direction of the aluminum raw material to form a sawtooth region, and using the same method to cut a sawtooth region on the outer surface of the second end, finally forming the aluminum part.

[0008] Optionally, the circumferential sawtooth groove includes a first sidewall and a second sidewall, the bottoms of the first sidewall and the second sidewall intersect, and the angle between the plane containing the first sidewall and the vertical direction is 10°-70°.

[0009] Optionally, the width of the opening at the top of the circumferential sawtooth groove is 0.02mm-0.5mm.

[0010] Optionally, the depth of the circumferential sawtooth groove is 0.02mm-0.5mm.

[0011] Optionally, the spacing between two adjacent circumferential sawtooth grooves is 0.02mm-0.5mm.

[0012] Optionally, the width of the serrated area is 1mm-500mm.

[0013] Optionally, the adhesive is an epoxy resin adhesive or a polyurethane adhesive, the coating thickness of the adhesive is 0.05mm-0.5mm, and the adhesive is applied by brush coating or spray gun coating.

[0014] An aluminum-plastic composite, manufactured using an aluminum-plastic composite processing method, includes an aluminum part. The aluminum part includes a first end, a second end, and a middle part. The cross-sectional area of ​​the middle part is larger than the cross-sectional area of ​​the first end and the second end. The outer periphery of both the first end and the second end is provided with a serrated area. The serrated area includes a plurality of circumferential serrated grooves evenly spaced along the length direction of the aluminum part. Adhesive is provided in the serrated area. A first injection molded body is sleeved on the outer wall of the first end, and a second injection molded body is sleeved on the outer wall of the second end.

[0015] Optionally, the circumferential sawtooth groove includes a first sidewall and a second sidewall, the bottoms of the first sidewall and the second sidewall intersect, the angle between the plane of the first sidewall and the vertical direction is 10°-70°, the width of the top opening of the circumferential sawtooth groove, the depth of the circumferential sawtooth groove, and the spacing between two adjacent circumferential sawtooth grooves are all 0.02mm-0.5mm, the width of the sawtooth area is 1mm-500mm, and the coating thickness of the adhesive is 0.05mm-0.5mm.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: by cutting multiple circumferential sawtooth grooves at intervals on the outer periphery of the end of the aluminum part raw material to form a sawtooth area of ​​a certain width, applying glue to the sawtooth area and letting it dry and cure naturally to form a solid glue, placing the end of the aluminum part into an injection molding machine, and using high temperature and pressure to thermoset the injection molding material, solid glue and the end of the aluminum part, and then letting it cool statically to form an aluminum-plastic composite, the glue is evenly distributed in the sawtooth area, which improves the connection strength between the aluminum part and the plastic part of the aluminum-plastic composite. Attached Figure Description

[0017] Figure 1 The image shown is a partial cross-sectional view of the aluminum-plastic composite of the present invention; Figure 2 The diagram shown is an enlarged schematic of the circumferential sawtooth groove of the present invention; Figure 3 The image shown is a partial cross-sectional view of the raw material for the aluminum parts of this invention. Figure 4 The image shown is a front view of the aluminum component of this invention; Figure 5 The image shown is a front view of the aluminum-plastic composite of the present invention; Figure 6 The diagram shown is a schematic diagram of the circumferential sawtooth groove in Comparative Example 1 of the present invention. Figure 7 The diagram shown is a schematic diagram of the circumferential sawtooth groove in Comparative Example 2 of the present invention. Figure 8 The diagram shown is a schematic diagram of the circumferential sawtooth groove in Comparative Example 3 of the present invention. Figure 9 The diagram shown is a schematic diagram of the circumferential sawtooth groove in Comparative Example 4 of the present invention.

[0018] In the diagram: 1. Aluminum part; 2. Adhesive; 3. First injection molded part; 4. Second injection molded part; 101. First end; 102. Second end; 103. Middle part; 104. Circumferential serrated groove; 1a. Straight section; 1b. Arc section; 1c. Connecting section; 1041. First sidewall; 1042. Second sidewall. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0020] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are used only for the convenience of describing the 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, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance, or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] Example 1 Reference Figures 1 to 5This embodiment provides a method for processing an aluminum-plastic composite, specifically including the following steps: providing an aluminum part 1, the aluminum part 1 including a first end 101, a second end 102 and a middle part 103, the cross-sectional area of ​​the middle part 103 being larger than the cross-sectional area of ​​the first end 101 and the second end 102, and the outer periphery of both the first end 101 and the second end 102 being provided with serrated areas; providing adhesive 2, uniformly applying the adhesive 2 to the serrated areas of the first end 101 and the second end 102, and allowing it to stand at room temperature for the adhesive 2 to dry and harden. The process involves: 1) providing injection molding material and an injection molding machine; 2) placing the first end 101 (after applying the adhesive) into the injection molding machine; 3) processing the injection molding material into a first injection body 3; 4) thermosetting the first injection body 3, adhesive 2, and first end 101; 5) placing the second end 102 (after applying the adhesive) into the injection molding machine; 6) processing the injection molding material into a second injection body 4; 7) thermosetting the second injection body 4, adhesive 2, and second end 102; and 8) allowing the injection-molded aluminum part 1 to cool and solidify to form an aluminum-plastic composite.

[0023] Providing aluminum part 1 includes the following steps: providing aluminum raw material, the aluminum raw material including a shell, the shell having a cavity, the shell including two oppositely arranged straight portions 1a and two oppositely arranged arc portions 1b, and a plurality of connecting portions 1c provided between the two straight portions 1a; providing a necking mold, placing both ends of the aluminum raw material into the necking mold in sequence for punching and necking to form a first end 101 and a second end 102, and forming an intermediate portion 103 between the first end 101 and the second end 102; providing a laser cutting machine, placing the first end 101 into the laser cutting machine, and cutting a plurality of circumferential sawtooth grooves 104 along the outer surface of the first end 101, the plurality of circumferential sawtooth grooves 104 being evenly spaced along the length direction of the aluminum raw material to form a sawtooth region, and using the same method to cut a sawtooth region on the outer surface of the second end 102, finally forming aluminum part 1.

[0024] The injection molding machine used in this process has high dimensional accuracy requirements. The aluminum raw material has a large dimensional error, and using it directly would lead to a mismatch with the injection molding machine port, affecting the quality of the finished product. Therefore, it is necessary to use aluminum raw material with dimensions slightly larger than the injection molding machine port size. A high-precision reducing mold is then used to punch and reduce the ends of the aluminum raw material, ensuring that the ends meet the preset dimensional requirements. This significantly reduces the dimensional error of the injection part of aluminum part 1 and improves the product quality of the aluminum-plastic composite.

[0025] Thermosetting molding of injection molding machines is an injection molding process for thermosetting materials. Its principle is to feed the dried injection molding material into the barrel, heat and plasticize it into a molten flow state under conditions below the crosslinking temperature, and then inject it into the mold cavity under high pressure and high speed through the internal screw. The mold continues to heat the material, causing the molecular chains of the raw material to undergo an irreversible three-dimensional network crosslinking reaction, and finally forming the desired injection molded body.

[0026] Using aluminum raw materials with dimensions slightly larger than the injection molding machine port, and punching and compressing the end through a high-precision shrinking mold, the end of aluminum part 1 is precisely matched to the size requirements of the injection molding machine port. This solves the injection matching problem caused by large dimensional errors in the aluminum raw materials and ensures the stability of the injection molded product quality.

[0027] The circumferential sawtooth groove 104 includes a first sidewall 1041 and a second sidewall 1042. The bottoms of the first sidewall 1041 and the second sidewall 1042 intersect, and the angle between the plane of the first sidewall 1041 and the vertical direction is 10°-70°.

[0028] The width of the opening at the top of the circumferential sawtooth groove 104 is 0.02mm-0.5mm.

[0029] The depth of the circumferential sawtooth groove 104 is 0.02mm-0.5mm.

[0030] The spacing between two adjacent circumferential sawtooth grooves 104 is 0.02mm-0.5mm.

[0031] The width of the serrated area ranges from 1mm to 500mm.

[0032] Adhesive 2 is epoxy resin adhesive or polyurethane adhesive. The coating thickness of adhesive 2 is 0.05mm-0.5mm. Adhesive 2 is applied by brush or spray gun.

[0033] The entire process of manufacturing aluminum-plastic composites is as follows: Aluminum blocks are heated to a semi-molten state, and the semi-molten aluminum material is extruded using an extruder to form a long strip of aluminum (i.e., the raw material for the aluminum part in this process). The two ends of the raw material are sequentially placed into a high-precision reducing mold for dimensional compression. The two ends of the raw material are then placed into a laser cutting machine for grooving, with multiple grooving intervals to form a serrated area. Adhesive 2 is applied to the serrated area using a brush or spray gun, and after application, it is left to stand at room temperature for two hours to allow adhesive 2 to cure. The end of aluminum part 1 is inserted into an injection molding machine, and the internal temperature of the injection molding machine is raised to 200℃-350℃ to melt the injection molding particles. The melted injection molding particles come into contact with the solid adhesive on the surface of the end of aluminum part 1. Under the action of high temperature, the solid adhesive is converted into liquid adhesive, reactivating the viscosity of adhesive 2. Finally, under the pressure of the injection molding machine, an injection molded body is formed on the outer periphery of the end of aluminum part 1, and the end of aluminum part 1, adhesive 2, and injection molded body are thermoset. Finally, the molded product is left to cool for two hours to form an aluminum-plastic composite.

[0034] The test procedures for pull-out force and airtightness of aluminum-plastic composites are as follows: The pull-out force test procedure involves using a pull-out force testing device. One end of the device clamps the portion of the aluminum part 1 near the first injection molded body 3 or near the second injection molded body 4, while the other end clamps either the first injection molded body 3 or the second injection molded body 4. The end clamping the aluminum part 1 remains stationary. A pull-out force of 30 MPa is applied along the length of the aluminum part 1 and in a direction away from the aluminum part 1. The test result meets the pull-out force requirements.

[0035] Air tightness test procedures, such as Figure 1 As shown, the inner wall of the open end of the first injection-molded body 3 is stepped. The upper surface of the end of the aluminum part 1 is connected to the stepped portion, forming an open area. An inflation device is used to seal this open area, and then air is continuously injected into the sealed area for 60 seconds, followed by pressure holding for another 60 seconds. Simultaneously, an airtightness testing device is used to detect the leakage at the aluminum-plastic joint. The test results show that the leaked gas is less than 0.15 Pa, meeting the airtightness requirements.

[0036] Cut an inverted triangular groove around the outer periphery of the end of the aluminum part raw material. The groove is 0.02mm-0.5mm wide and 0.02mm-0.5mm deep. Adjust the position of the aluminum part raw material and cut multiple parallel circumferential sawtooth grooves 104 at intervals of 0.02mm-0.5mm. The multiple circumferential sawtooth grooves 104 form a sawtooth area with a width of 1mm-500mm. Apply glue 2 to the sawtooth area and let it air dry and cure at room temperature to form a solid glue. Place the end of the aluminum part 1 into an injection molding machine. The injection molding machine uses high temperature and pressure to thermoset the injection material, solid glue and the end of the aluminum part 1. After static cooling, an aluminum-plastic composite is formed. Glue 2 is evenly distributed in the sawtooth area, which improves the connection strength between the aluminum part 1 and the plastic part of the aluminum-plastic composite. The pull-out force and air tightness tests meet the requirements.

[0037] Example 2 Reference Figures 1 to 5 This embodiment provides an aluminum-plastic composite, specifically including an aluminum part 1. The aluminum part 1 includes a first end 101, a second end 102, and a middle part 103. The cross-sectional area of ​​the middle part 103 is larger than the cross-sectional area of ​​the first end 101 and the second end 102. The outer periphery of the first end 101 and the second end 102 are provided with serrated areas. The serrated areas include a plurality of circumferential serrated grooves 104 evenly spaced along the length direction of the aluminum part 1. Adhesive 2 is provided in the serrated areas. A first injection molded body 3 is sleeved on the outer wall of the first end 101, and a second injection molded body 4 is sleeved on the outer wall of the second end 102.

[0038] The circumferential sawtooth groove 104 includes a first sidewall 1041 and a second sidewall 1042. The bottoms of the first sidewall 1041 and the second sidewall 1042 intersect. The angle between the plane containing the first sidewall 1041 and the vertical direction is 10°-70°. The width of the top opening of the circumferential sawtooth groove 104, the depth of the circumferential sawtooth groove 104, and the spacing between two adjacent circumferential sawtooth grooves 104 are all 0.02mm-0.5mm. The width of the sawtooth area is 1mm-500mm. The coating thickness of the adhesive 2 is 0.05mm-0.5mm.

[0039] Comparative Example 1 like Figure 6 As shown, the circumferential sawtooth groove 104a includes two symmetrically arranged inclined sidewalls, the bottoms of the two inclined sidewalls intersect, and the multiple circumferential sawtooth grooves 104a are continuously arranged.

[0040] Comparative Example 2 like Figure 7 As shown, the circumferential sawtooth groove 104b includes a vertical sidewall and an inclined sidewall, the bottoms of the vertical sidewall and the inclined sidewall intersect, and the multiple circumferential sawtooth grooves 104b are continuously arranged.

[0041] Comparative Example 3 like Figure 8 As shown, the circumferential sawtooth groove 104c includes two symmetrically arranged vertical sidewalls and a horizontal bottom wall. The two ends of the horizontal bottom wall intersect the bottom of the two vertical sidewalls respectively. The multiple circumferential sawtooth grooves 104c are arranged at intervals, and the interval distance is equal to the distance between the two vertical sidewalls.

[0042] Comparative Example 4 like Figure 9 As shown, the circumferential sawtooth groove 104d includes two symmetrically arranged vertical sidewalls and an arc-shaped bottom wall. The two ends of the arc-shaped bottom wall intersect with the bottom of the two vertical sidewalls respectively. The multiple circumferential sawtooth grooves 104d are arranged at intervals, and the interval distance is equal to the distance between the two vertical sidewalls.

[0043] In this embodiment, the multiple circumferential sawtooth grooves 104 can be spaced apart or continuously arranged. In the four comparative examples above, the shape features of the circumferential sawtooth grooves 104 can be combined with each other. For example, in Comparative Examples 1 and 2, the multiple circumferential sawtooth grooves 104a and 104b can be spaced apart. In Comparative Examples 3 and 4, the distance between two adjacent circumferential sawtooth grooves 104c or 104d can be greater than or less than the distance between two vertical sidewalls.

[0044] Using the same pull-out force and airtightness test methods, in the four comparative examples and the combination of comparative examples, the pull-out force test met the requirements, and the amount of gas leaked in the airtightness test was higher than that in this scheme.

[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for processing aluminum-plastic composites, characterized in that, Includes the following steps: An aluminum part (1) is provided, the aluminum part (1) includes a first end (101), a second end (102) and a middle part (103), the cross-sectional area of ​​the middle part (103) is larger than the cross-sectional area of ​​the first end (101) and the second end (102), and the outer periphery of the first end (101) and the second end (102) are provided with serrated areas; Provide glue (2), apply glue (2) evenly to the serrated areas of the first end (101) and the second end (102), let stand at room temperature, and wait for the glue (2) to dry and cure to form a solid glue; Provide injection molding materials and injection molding machine, put the injection molding materials into the injection molding machine, put the first end (101) after applying glue into the injection molding machine, the injection molding machine processes the injection molding materials into the first injection body (3), and thermosets the first injection body (3), glue (2) and the first end (101), and then put the second end (102) after applying glue into the injection molding machine, the injection molding machine processes the injection molding materials into the second injection body (4), and thermosets the second injection body (4), glue (2) and the second end (102); Finally, the injection-molded aluminum part (1) is left to cool and stand to form an aluminum-plastic composite.

2. The aluminum-plastic composite processing method according to claim 1, characterized in that, The provision of the aluminum component (1) includes the following steps: Aluminum raw materials are provided, the aluminum raw materials include a shell, the shell has a cavity, the shell includes two oppositely arranged straight parts (1a) and two oppositely arranged arc parts (1b), and a plurality of connecting parts (1c) are provided between the two straight parts (1a). A necking mold is provided, and the two ends of the aluminum raw material are sequentially placed into the necking mold to punch and compress the neck, forming a first end (101) and a second end (102), and an intermediate part (103) is formed between the first end (101) and the second end (102). A laser cutting machine is provided. The first end (101) is placed in the laser cutting machine and multiple circumferential sawtooth grooves (104) are cut along the outer surface of the first end (101). The multiple circumferential sawtooth grooves (104) are evenly spaced along the length direction of the aluminum raw material to form a sawtooth area. The same method is used to cut a sawtooth area on the outer surface of the second end (102) to finally form an aluminum part (1).

3. The aluminum-plastic composite processing method according to claim 2, characterized in that, The circumferential sawtooth groove (104) includes a first sidewall (1041) and a second sidewall (1042), the bottoms of the first sidewall (1041) and the second sidewall (1042) intersect, and the angle between the plane of the first sidewall (1041) and the vertical direction is 10°-70°.

4. The aluminum-plastic composite processing method according to claim 2, characterized in that, The width of the opening at the top of the circumferential sawtooth groove (104) is 0.02mm-0.5mm.

5. The aluminum-plastic composite processing method according to claim 2, characterized in that, The depth of the circumferential sawtooth groove (104) is 0.02mm-0.5mm.

6. The aluminum-plastic composite processing method according to claim 2, characterized in that, The distance between two adjacent circumferential sawtooth grooves (104) is 0.02mm-0.5mm.

7. The aluminum-plastic composite processing method according to claim 1, characterized in that, The width of the serrated area is 1mm-500mm.

8. The aluminum-plastic composite processing method according to claim 1, characterized in that, The adhesive (2) is an epoxy resin adhesive or a polyurethane adhesive, the coating thickness of the adhesive (2) is 0.05mm-0.5mm, and the adhesive (2) is applied by brush coating or spray gun coating.

9. An aluminum-plastic composite, characterized in that, The aluminum-plastic composite is manufactured using the processing method of any one of claims 1-8, comprising an aluminum part (1), the aluminum part (1) comprising a first end (101), a second end (102) and a middle part (103), the cross-sectional area of ​​the middle part (103) being larger than the cross-sectional area of ​​the first end (101) and the second end (102), the outer periphery of the first end (101) and the second end (102) being provided with a serrated area, the serrated area comprising a plurality of circumferential serrated grooves (104) evenly spaced along the length direction of the aluminum part (1), the serrated area being provided with adhesive (2), the outer wall of the first end (101) being sleeved with a first injection molded body (3), and the outer wall of the second end (102) being sleeved with a second injection molded body (4).

10. The aluminum-plastic composite according to claim 9, characterized in that, The circumferential sawtooth groove (104) includes a first sidewall (1041) and a second sidewall (1042). The bottoms of the first sidewall (1041) and the second sidewall (1042) intersect. The angle between the plane of the first sidewall (1041) and the vertical direction is 10°-70°. The width of the top opening of the circumferential sawtooth groove (104), the depth of the circumferential sawtooth groove (104), and the spacing between two adjacent circumferential sawtooth grooves (104) are all 0.02mm-0.5mm. The width of the sawtooth area is 1mm-500mm. The coating thickness of the adhesive (2) is 0.05mm-0.5mm.

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