Composite gas cylinder and preparation method thereof

Abstract

This invention relates to the field of gas cylinder molding technology, specifically to a composite gas cylinder and its preparation method. A composite gas cylinder includes: a metal valve seat nozzle; a composite adhesive layer disposed on the adhesive surface of the metal valve seat nozzle, the composite adhesive layer comprising microscopic anchoring layers, physicochemical activation layers, and interface transition layers; and a plastic bottle body, the plastic bottle body being bonded to the adhesive surface of the metal valve seat nozzle via the composite adhesive layer. This invention provides a composite gas cylinder and its preparation method to solve the problem that during the composite cylinder preparation process, when an adhesive or adhesive layer is applied between the metal valve seat and the bottle body, the adhesive / adhesive layer itself provides a bond. However, due to the precision of dimensional control, the bonding process inevitably results in gaps or misfitting phenomena, leading to insufficient bonding strength between the metal valve seat and the bottle body, thus affecting performance under high-pressure loads.

Description

Technical Field

[0001] This invention relates to the field of gas cylinder molding technology, specifically to a composite gas cylinder and its preparation method. Background Technology

[0002] High-pressure gas storage technology is one of the most widely used technologies in vehicle-mounted gas supply systems. Among them, fully wound plastic-lined gas cylinders have become the mainstream development direction in the field of high-pressure gas cylinders due to their outstanding advantages such as light weight, good fatigue resistance, and low manufacturing cost.

[0003] The plastic inner liner requires a metal insert at its end to serve as a gas filling and releasing channel, making it one of the most demanding and structurally critical components of the gas cylinder. The metal insert is bonded to the plastic inner liner primarily by molten plastic encapsulating and then cooling and solidifying it onto a specific interface of the metal insert. The interfacial bonding strength of this method directly determines the performance of the gas cylinder under high-pressure cyclic loads.

[0004] Currently, the main technical means to improve the bonding strength between metal inserts and plastics is adhesive bonding, that is, applying an adhesive or adhesive layer between the metal valve seat and the bottle body, and bonding through the adhesive / adhesive layer itself. However, due to the precision of dimensional control, the adhesive bonding process will inevitably have certain gaps or misfits, resulting in insufficient bonding strength between the metal valve seat and the bottle body, affecting the performance under high pressure loads. Summary of the Invention

[0005] This invention provides a composite gas cylinder and its preparation method to solve the problem that during the composite cylinder preparation process, when an adhesive or adhesive layer is applied between the metal valve seat and the cylinder body, the adhesive / adhesive layer itself forms a bond. However, due to the precision of dimensional control, the bonding process inevitably has certain gaps or misfits, resulting in insufficient bonding strength between the metal valve seat and the cylinder body, which affects the performance under high pressure loads.

[0006] In a first aspect, the present invention provides a composite gas cylinder, comprising: Metal valve seat bottle neck; A composite adhesive layer is disposed on the adhesive surface of the metal valve seat bottle opening, and the composite adhesive layer includes micro-anchoring layer, physicochemical activation layer and interface transition layer. The plastic bottle body is bonded to the metal valve seat bottle mouth via a composite adhesive layer.

[0007] Beneficial effects: Laser etching pretreatment is performed on the metal valve seat bottle neck, followed by a coating process to obtain a composite adhesive layer. The plastic bottle body and the metal valve seat bottle neck are then bonded together using a plastic molding process. By using the composite adhesive layer, the bond is stronger than simple adhesive bonding, transforming the interface structure from "single anchorage" to "three-dimensional synergy." This ensures a close fit, improves the bonding strength between the metal valve seat bottle neck and the bottle body, and guarantees performance under high-pressure loads.

[0008] Secondly, the present invention also provides a method for preparing a composite gas cylinder, wherein the metal valve seat bottle mouth is pretreated by laser etching, a composite adhesive layer is obtained by coating process, and the plastic bottle body and the metal valve seat bottle mouth are bonded by plastic molding process and composite adhesive layer.

[0009] Beneficial effects: The pretreatment step involves laser pretreatment of the metal insert surface to remove the surface passivation layer and create micro-roughness; the surface activation step involves surface activation treatment of the pretreated insert surface to construct a micro / nano-scale active surface layer; and the intermediate layer formation step involves coating the active surface layer with an intermediate layer material to form an interface transition layer. This results in a three-layer composite structure consisting of a physical roughening layer, a surface activation layer, and an intermediate layer, forming a composite interface structure composed of a "micro-mechanical anchoring layer (S1) + a physicochemical activation layer (S2) + an interface transition layer (S3)". This structure achieves synergistic enhancement of mechanical interlocking, chemical bonding, and intermolecular forces, upgrading the interface bonding force from simple physical adsorption to a robust three-dimensional bond.

[0010] In one optional embodiment, when pre-treating the metal valve seat bottle neck, a micro-anchoring layer is first obtained through laser etching pre-treatment, followed by a physicochemical activation pre-treatment to obtain a physicochemical activation layer, and then an adhesive or adhesive layer is coated on the bonding surface of the metal valve seat bottle neck to obtain an interface transition layer.

[0011] In one optional embodiment, during the laser etching pretreatment, the bonding surface of the metal valve seat bottle neck is scanned by laser at a scanning speed of 5-60 cm / s. 2 The scan rate is 1000 m / min, the protective gas is high-purity argon, and the number of scans is 3 to 10.

[0012] In one alternative embodiment, the surface activation pretreatment is one of polarization treatment, hard anodizing treatment, or chemical conversion film treatment.

[0013] In one alternative implementation, the polarization process involves atmospheric pressure plasma treatment or vacuum plasma treatment.

[0014] In one optional embodiment, after applying an adhesive or adhesive layer to the bonding surface of the metal valve seat bottle neck, it is baked at 50°C-200°C for 10-30 minutes.

[0015] In one optional embodiment, the adhesive is one of vinyltriethoxysilane, γ-chloropropyltrichlorosilane, and chloromethyltriethoxysilane; or, the adhesive layer is one of polyolefin, ethylene-vinyl acetate copolymer, and maleic anhydride-grafted polyethylene.

[0016] In one optional embodiment, the molding process of the plastic part is one of blow molding, injection molding, or rotational molding.

[0017] In one alternative embodiment, the metal valve seat bottle neck is placed into a molding die, and the bottle body and the metal valve seat bottle neck are connected by heating the die. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the metal valve seat bottle opening according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a composite gas cylinder according to an embodiment of the present invention.

[0020] Explanation of reference numerals in the attached diagram: 1. Metal valve seat bottle mouth; 101. Adhesive surface; 2. Plastic bottle body. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] The following is combined Figures 1 to 2 The following describes embodiments of the present invention.

[0023] According to an embodiment of the present invention, a composite gas cylinder is provided, comprising: a metal valve seat cylinder opening 1; a composite adhesive layer disposed on the adhesive surface 101 of the metal valve seat cylinder opening 1, the composite adhesive layer comprising micro-anchoring layering, physicochemical activation layering and interface transition layering; and a plastic cylinder body 2, the plastic cylinder body 2 being bonded to the adhesive surface 101 of the metal valve seat cylinder opening 1 through the composite adhesive layer.

[0024] The metal valve seat bottle neck 1 undergoes laser etching pretreatment, followed by a coating process to obtain a composite adhesive layer. The plastic bottle body 2 is then bonded to the metal valve seat bottle neck 1 using a plastic molding process. By using the composite adhesive layer, the bond is stronger than simple adhesive bonding, transforming the interface structure from "single anchorage" to "three-dimensional synergy." This ensures a close fit, enhances the bonding strength between the metal valve seat bottle neck 1 and the bottle body, and guarantees performance under high-pressure loads.

[0025] It should be noted that, in this embodiment, the materials used to manufacture the metal inserts include, but are not limited to, alloy steel (34Mn2V, 37Mn, 30CrMo, 34CrMo), austenitic stainless steel (S30408, S30403, S31608, S31603), austenitic-ferritic duplex stainless steel (S21953), and aluminum alloys (6351A, 6082A, 6061A, 5283A, 7060, 7032, 2001); furthermore, such as Figure 1 , Figure 2 As shown, this embodiment does not impose a specific limit on the number of metal valve seat openings 1 provided on the plastic bottle body 2.

[0026] According to an embodiment of the present invention, another aspect provides a method for preparing a composite gas cylinder. The method involves laser etching pretreatment of the metal valve seat nozzle 1, obtaining a composite adhesive layer using a coating process, and bonding the plastic bottle body 2 to the metal valve seat nozzle 1 through a plastic molding process and the composite adhesive layer. In this embodiment, the pretreatment steps include: laser pretreatment of the metal insert surface to remove the surface passivation layer and form micro-roughness; surface activation steps: surface activation treatment of the pretreated insert surface to construct a micro-nano scale active surface layer; and intermediate layer formation steps: coating an intermediate layer material onto the active surface layer to form an interface transition layer. This creates a three-layer composite structure consisting of a physical roughening layer, a surface activation layer, and an intermediate layer from the inside out. This constructs a composite interface structure composed of a "micro-mechanical anchoring layer (S1) + a physicochemical activation layer (S2) + an interface transition layer (S3)". This structure achieves synergistic enhancement of mechanical interlocking, chemical bonding, and intermolecular forces, upgrading the interface bonding force from simple physical adsorption to a strong three-dimensional bond.

[0027] In one embodiment, when pre-treating the metal valve seat bottle neck 1, a micro-anchoring layer is first obtained through laser etching pre-treatment, followed by a physicochemical activation pre-treatment to obtain a physicochemical activation layer. Then, an adhesive or adhesive layer is coated on the bonding surface 101 of the metal valve seat bottle neck 1 to obtain an interface transition layer. The laser etching pre-treatment is not only for cleaning but also for removing the inert layer and exposing the highly active substrate, laying the foundation for subsequent activation. The surface activation treatment introduces an activation layer with high surface energy, rich in polar functional groups or micro / nano pores, onto the roughened surface through methods such as polarization treatment, anodizing, or chemical conversion film. This layer can form a strong chemical bond with the intermediate layer. Finally, an adhesive or adhesive layer is coated to obtain an interface transition layer.

[0028] In one embodiment, during the laser etching pretreatment, the bonding surface 101 of the metal valve seat bottle neck 1 is scanned with a laser at a scanning speed of 5-60 cm / s. 2 The scan rate is 1000 m / min, the protective gas is high-purity argon, and the number of scans is 3 to 10.

[0029] Laser etching pretreatment of metal inserts aims to remove the passivation and oxide layers on the metal surface, exposing the highly reactive components of the metal insert substrate. The laser type used in the laser etching pretreatment is a femtosecond / nanosecond laser, with a scanning rate of 5–60 cm⁻¹. 2 The scanning speed is set to high-purity argon gas, and the number of scans is 3-10. The metal valve seat bottle neck 1 is placed on the laser etching workpiece clamping stage, the gas protection is activated, and the scanning rate and number of scans are set. The surface is scanned uniformly up and down along the bonding surface 101. After processing, the roughness of the bonding surface 101 of the metal valve seat bottle neck 1 is 0.1μm-5μm. Finally, the surface of the metal valve seat bottle neck 1 is cleaned with a compressed air gun to ensure no residue remains. It should be noted that in this embodiment, the bonding surface 101 is used to connect to the plastic bottle body 2.

[0030] In one embodiment, the surface activation pretreatment is one of polarization treatment, hard anodizing treatment, or chemical conversion film treatment. The purpose is to introduce polar groups, micro-nano scale mechanical connection anchors, or micropores on the metal surface to achieve a composite interface structure with synergistic physical anchoring and chemical bonding and high interface stability.

[0031] In one embodiment, the surface activation pretreatment is one of polarization treatment, hard anodizing treatment, or chemical conversion film treatment. The polarization treatment can be performed using atmospheric pressure or vacuum plasma treatment equipment.

[0032] Atmospheric pressure plasma treatment: power 500~1200W, working gas is air, treatment speed 20~70mm, working distance 2mm~10cm, treatment time 5~15min. Place the metal valve seat bottle mouth 1 on the workpiece clamping table, set the equipment power, treatment rate and time; after treatment, transfer the metal valve seat bottle mouth 1 to the next process.

[0033] Vacuum plasma treatment: Power 600~5000W, working gas can be selected from Ar, O2, N2, H2, CO2, NOx, CF4, etc., mixed in proportion, treatment time 5~15min. After setting the equipment parameters, place the metal valve seat bottle mouth 1 into the plasma chamber, close the chamber door and evacuate the chamber to below 3Pa; after introducing the working gas to 10~100Pa, start the plasma generator to begin treating the valve seat. After treatment, transfer the metal valve seat bottle mouth 1 to the next process.

[0034] Hard anodizing treatment: The electrolyte contains 200~280g / L H2SO4 and 5~15g / L oxalic acid; the process temperature is -5~5℃; electrolysis is performed using a constant current method with a current intensity of 0.5~2A / dm³. 2 The electrolysis time is 5~30 min, and the hard anodizing is completed to a thickness greater than 40 μm. After treatment, the metal valve seat bottle mouth 1 is transferred to the next process.

[0035] Chemical conversion membrane treatment: The pretreated metal valve seat bottle mouth 1 is treated with chemical conversion membrane by immersion or brush coating. The membrane solution may include phosphating solution, complexate membrane solution, rare earth conversion membrane solution. The solution is heated in a water bath at 20~70℃ for 10~30 minutes and then placed in an oven at 50~70℃ for 1 hour. After treatment, the metal valve seat bottle mouth 1 is transferred to the next process.

[0036] In one embodiment, after applying an adhesive or adhesive layer to the bonding surface 101 of the metal valve seat bottle neck 1, it is baked at 50°C-200°C for 10 min-30 min.

[0037] In one embodiment, the adhesive is one of vinyltriethoxysilane, γ-chloropropyltrichlorosilane, and chloromethyltriethoxysilane; or, the adhesive layer is one of polyolefin, ethylene-vinyl acetate copolymer, and maleic anhydride-grafted polyethylene.

[0038] In this embodiment, the adhesive surface 101 after surface activation pretreatment can be coated on the valve seat sealing surface using a silane coupling agent, aluminum-plastic film, hot-melt adhesive layer, etc., and then baked in an oven at 50~200℃ for 10~30 minutes. This ensures a reliable bond between the adhesive surface 101 of the metal valve seat bottle mouth 1 and the adhesive / intermediate layer. The adhesive is one of vinyltriethoxysilane, γ-chloropropyltrichlorosilane, or chloromethyltriethoxysilane. Alternatively, the adhesive layer is one of polyolefin, ethylene-vinyl acetate copolymer, or maleic anhydride-grafted polyethylene.

[0039] In one embodiment, the molding process for the plastic part is one of blow molding, injection molding, or rotational molding.

[0040] In one embodiment, the metal valve seat bottle neck 1 is placed into a molding die, and the bottle body is formed and the metal valve seat bottle neck 1 is connected by heating the die.

[0041] Blow molding process: The metal valve seat bottle mouth 1 is precisely positioned in the mold. The material barrel is heated to 150~240℃ to ensure that the plastic is completely melted and reaches a uniform viscosity. The die is preheated to 180~220℃ to ensure stable material output and pre-blown preform. The blow molding mold is closed to clamp the preform. Gas is injected through the tension rod to make the plastic completely fit the mold. The blowing pressure is 2~4MPa and the blowing time is 5~20s. After blow molding is completed, the mold is opened and the composite gas cylinder finished product is taken out.

[0042] Injection Molding Process: The metal valve seat bottle neck 1 is precisely positioned in the mold. The barrel is heated to 150~240℃ to ensure that the plastic is completely melted and reaches a uniform viscosity. The mold temperature is preheated to 180~220℃. The injection pressure is controlled at 50~150MPa, and the molten plastic is injected into the preform mold. The pressure is held at 50%-80% of the injection pressure for 2~30s. After the pressure is held, 10~20℃ cooling water is introduced, and low-temperature air is injected into the bottle to cool and solidify the plastic. After completion, the mold is opened and the composite gas cylinder product is removed.

[0043] Rotational molding process: The metal valve seat bottle neck 1 is precisely positioned in the mold. The temperature inside the mold is maintained at 0~150℃ for 10~30 minutes, followed by 150℃ for 5~15 minutes, and then 150~220℃ for 5~15 minutes. The temperature inside the mold and the end cap can be detected by infrared and wireless temperature measurement modules to ensure that the maximum temperature inside the mold is 220℃~230℃. After cooling, the cylinder is demolded. The cooling process uses air cooling and water mist cooling, with a fan speed of 500~2000rpm for 40~50 minutes. After completion, the mold is opened and the composite gas cylinder is removed. The bonding surface diameter of the metal valve seat bottle neck is 30mm-500mm, and the overall length of the composite gas cylinder is 300mm-2500mm and the diameter is 300mm-1000mm.

[0044] Example 1 Taking the metal valve seat bottle neck 1 as an example, which is made of one of 30CrMo / S30408 / S21953, the preparation process includes the following steps: (1) Laser etching: The laser type is femtosecond / nanosecond laser, and the scanning rate is 5~60cm. 2 The scan rate is 1000 m / min, the protective gas is high-purity argon, and the number of scans is 3 to 10.

[0045] Place the metal valve seat bottle mouth 1 on the laser etching workpiece clamping stage, turn on the gas protection, and set the scanning rate and number of scans; scan evenly along the outer periphery of the bonding surface 101. The bonding surface 101 of the processed metal valve seat bottle mouth 1 is 0.1μm~5μm; finally, use a compressed air gun to clean the surface of the metal valve seat bottle mouth 1 to ensure that there is no dirt residue.

[0046] (2) Atmospheric pressure plasma treatment: power 500~1200W, working gas is air, processing speed 20~70mm, working distance 2mm~10cm, processing time is 5~15min. Place the metal valve seat bottle mouth 1 on the workpiece clamping table, set the equipment power, processing speed and time; after processing, transfer the metal valve seat bottle mouth 1 to the next process operation.

[0047] Vacuum plasma treatment: power 600~5000W, working gas can be selected from Ar, O2, N2, H2, CO2, NO x Mix CF4 and other components in a specified ratio, and process for 5-15 minutes. After setting the equipment parameters, place the valve seat inside the plasma chamber, close the chamber door, and evacuate the chamber to below 3 Pa. Introduce working gas to 10-100 Pa, then start the plasma generator to process the valve seat. After processing, transfer the insert to the next step.

[0048] It should be noted that in step (2), atmospheric pressure plasma treatment and vacuum plasma treatment are optional, that is, you can choose one of the two treatment methods.

[0049] (3) Enter the adhesive / intermediate layer coating process. The silane coupling agent is coated on the bonding surface 101 of the metal valve seat bottle mouth 1 and baked in an oven at 50~200℃ for 10~30min. This ensures that the valve seat sealing surface and the adhesive / intermediate layer form a reliable bond.

[0050] The silane coupling agent may be one of the following: vinyltriethoxysilane, γ-chloropropyltrichlorosilane, or chloromethyltriethoxysilane.

[0051] (4) Blow molding process: The metal valve seat bottle mouth 1 is precisely positioned in the mold. The material barrel is heated to 150~240℃ to ensure that the plastic is completely melted and reaches a uniform viscosity. The die is preheated to 180~220℃ to ensure stable material output and pre-blown preform. The blow molding mold is closed, the preform is clamped, and gas is injected through the stretching rod to make the plastic completely adhere to the mold. The blowing pressure is 2~4MPa and the blowing time is 5~20s. After blow molding is completed, the mold is opened and the product is taken out.

[0052] The resulting composite gas cylinder is obtained.

[0053] Example 2 Taking the metal valve seat bottle neck 1 made of 6061A material as an example, the preparation process includes the following steps: (1) Laser etching: The laser type is femtosecond / nanosecond laser, and the scanning rate is 5~60cm. 2 The scan rate is 1000 m / min, the protective gas is high-purity argon, and the number of scans is 3 to 10.

[0054] Place the metal valve seat bottle mouth 1 on the laser etching workpiece clamping stage, turn on the gas protection, and set the scanning rate and number of scans; scan evenly along the outer periphery of the bonding surface 101, and the roughness of the bonding surface 101 of the processed metal valve seat bottle mouth 1 is 0.1μm~5μm; finally, use a compressed air gun to clean the surface of the metal valve seat bottle mouth 1 to ensure that there is no dirt residue.

[0055] (2) Hard anodizing treatment: The electrolyte contains 200~280g / L H2SO4 and 5~15g / L oxalic acid. The process temperature is -5~5℃. Electrolysis is performed using a constant current method with a current intensity of 0.5~2A / dm. 2 The electrolysis time is 5~30min, and the hard oxidation is formed to a thickness greater than 40μm. After treatment, the metal valve seat bottle mouth 1 is transferred to the next process.

[0056] (3) Enter the intermediate layer coating process, use hot melt adhesive layer to coat the adhesive surface 101 of the metal valve seat bottle mouth 1, and bake in the oven at 50~200℃ for 10~30min to make the adhesive surface 101 of the metal valve seat bottle mouth 1 form a reliable bond with the adhesive / intermediate layer.

[0057] The adhesive layer may be one of the following: polyolefin, ethylene-vinyl acetate copolymer, or maleic anhydride-grafted polyethylene.

[0058] (4) Injection molding process: The metal valve seat bottle mouth 1 is precisely positioned in the mold. The barrel is heated to 150~240℃ to ensure that the plastic is completely melted and reaches a uniform viscosity. The mold temperature is preheated to 180~220℃. The injection pressure is controlled at 50~150MPa. The molten plastic is injected into the preform mold. The pressure is held at 50%-80% of the injection pressure for 2~30s. After the pressure is held, 10~20℃ cooling water is introduced. Low temperature air is injected into the bottle to cool and solidify the plastic.

[0059] The resulting composite gas cylinder is obtained.

[0060] Example 3 Taking the metal valve seat bottle neck 1 made of 7060 as an example, the preparation process includes the following steps: (1) Laser etching: The laser type is femtosecond / nanosecond laser, and the scanning rate is 5~60cm. 2 The scan rate is 1000 m / min, the protective gas is high-purity argon, and the number of scans is 3 to 10.

[0061] Place the metal valve seat bottle mouth 1 on the laser etching workpiece clamping stage, turn on the gas protection, and set the scanning rate and number of scans; scan evenly up and down along the outer periphery of the bonding surface 101, and the roughness of the valve seat sealing surface after processing is 0.1μm~5μm; finally, use a compressed air gun to clean the surface of the metal valve seat bottle mouth 1 to ensure that there is no dirt residue.

[0062] (2) Chemical conversion membrane treatment: The pretreated metal valve seat bottle mouth 1 is chemically converted by immersion or brush coating. The membrane solution may include phosphating solution, complexate membrane solution, rare earth conversion membrane solution. After heating in a water bath at 20~70℃ and reacting for 10~30min, it is placed in an oven at 50~70℃ for 1h. After treatment, the insert is transferred to the next process.

[0063] (3) Enter the adhesive / intermediate layer coating process. The aluminum-plastic film is coated on the bonding surface 101 of the metal valve seat bottle mouth 1. It is baked in the oven at 50~200℃ for 10~30min to make the bonding surface 101 of the metal valve seat bottle mouth 1 and the adhesive / intermediate layer form a reliable bond.

[0064] (4) Rotational molding process: The metal valve seat bottle mouth 1 is precisely positioned in the mold. The temperature inside the mold is maintained at 0~150℃ for 10~30min, 150℃ for 5~15min, and 150~220℃ for 5~15min. The temperature inside the mold and the end cap is detected by infrared and wireless temperature measurement modules. The maximum temperature inside the mold is guaranteed to be 220℃~230℃. Cooling and demolding are then carried out. The cooling process adopts air cooling and water mist cooling, with a fan speed of 500~2000rpm and a time of 40~50min.

[0065] The resulting composite gas cylinder is obtained.

[0066] It should be noted that in the above three embodiments, the surface activation pretreatment process in step (2) can be interchanged; the coating process in step (3) can be interchanged; and the plastic part molding process in step (4) can also be interchanged.

[0067] Table 1. Adhesion force between the bottle neck and bottle body of metal valve seats under different materials and manufacturing processes.

[0068] After manufacturing is completed, samples are made to characterize the interfacial bonding strength and the peel strength is measured.

[0069] From the data table above, we can see that the peel strength of the untreated same material is significantly less than the peel strength of the bond obtained by laser etching + other processes. Furthermore, the peel strength of the same material increases with the increase of preparation steps, and the peel strength of the product obtained by this application is even stronger.

[0070] The composite gas cylinder and preparation method provided by the present invention have the following advantages: (1) The metal valve seat bottle mouth 1 is pretreated by laser etching and coated to obtain a composite adhesive layer. The plastic bottle body 2 and the metal valve seat bottle mouth 1 are bonded by plastic molding process. By setting the composite adhesive layer, the bonding is stronger than simple bonding, and the interface structure changes from "single anchoring" to "three-dimensional collaboration", ensuring the fit setting; (2) Through the pretreatment step: the surface of the metal insert is pretreated by laser to remove the surface passivation layer and form micro roughness; the surface activation step: the surface of the pretreated insert is activated to construct a micro-nano scale active surface layer; the intermediate layer formation step: the intermediate layer material is coated on the active surface layer to form an interface transition layer. It has a three-layer composite structure consisting of a physical roughening layer, a surface activation layer and an intermediate layer from the inside out. It constructs a composite interface structure consisting of a "micro-mechanical anchoring layer (S1) + physical and chemical activation layer (S2) + interface transition layer (S3)". This structure realizes the synergistic effect of mechanical interlocking, chemical bonding and intermolecular forces, and upgrades the interface bonding force from simple physical adsorption to a firm three-dimensional bonding. (3) The bonding force of untreated materials is smaller, while the bonding force after treatment is larger.

[0071] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A composite gas cylinder, characterized in that, include: Metal valve seat bottle neck (1); A composite adhesive layer is disposed on the adhesive surface (101) of the metal valve seat bottle mouth (1). The composite adhesive layer includes micro-anchoring layer, physicochemical activation layer and interface transition layer. The plastic bottle body (2) is bonded to the adhesive surface (101) of the metal valve seat bottle mouth (1) by a composite adhesive layer.

2. A method for preparing a composite gas cylinder, used to prepare the composite gas cylinder of claim 1, characterized in that, Laser etching pretreatment is performed on the metal valve seat bottle mouth (1), and a composite adhesive layer is obtained by coating process. The plastic bottle body (2) and the metal valve seat bottle mouth (1) are bonded together by plastic molding process and composite adhesive layer.

3. The method for preparing the composite gas cylinder according to claim 2, characterized in that, When pre-treating the metal valve seat bottle mouth (1), firstly, a micro-anchoring layer is obtained by laser etching pre-treatment, then a physical and chemical activation layer is obtained by surface activation pre-treatment, and then an adhesive or adhesive layer is coated on the bonding surface (101) of the metal valve seat bottle mouth (1) to obtain an interface transition layer.

4. The method for preparing the composite gas cylinder according to claim 3, characterized in that, In the laser etching pretreatment, the bonding surface (101) of the metal valve seat bottle mouth (1) is scanned by laser at a scanning speed of 5~60cm. 2 The scan rate is 1000 m / min, the protective gas is high-purity argon, and the number of scans is 3 to 10.

5. The method for preparing the composite gas cylinder according to claim 3, characterized in that, The surface activation pretreatment is one of polarization treatment, hard anodizing treatment, or chemical conversion film treatment.

6. The method for preparing the composite gas cylinder according to claim 5, characterized in that, During the polarization process, atmospheric pressure plasma treatment or vacuum plasma treatment is performed.

7. The method for preparing the composite gas cylinder according to claim 2, characterized in that, After applying an adhesive or adhesive layer to the bonding surface (101) of the metal valve seat bottle mouth (1), bake it at 50℃-200℃ for 10min-30min.

8. The method for preparing the composite gas cylinder according to claim 7, characterized in that, The adhesive is one of vinyltriethoxysilane, γ-chloropropyltrichlorosilane, and chloromethyltriethoxysilane; or, the adhesive layer is one of polyolefin, ethylene-vinyl acetate copolymer, and maleic anhydride-grafted polyethylene.

9. The method for preparing the composite gas cylinder according to claim 2, characterized in that, The molding process of the plastic part is one of blow molding, injection molding, or rotational molding.

10. The method for preparing the composite gas cylinder according to claim 9, characterized in that, The metal valve seat bottle mouth (1) is placed into the molding mold, and the bottle body is formed and the metal valve seat bottle mouth (1) is connected by heating the mold.

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