Forming process of plastic inner container of vehicle-mounted hydrogen storage bottle of heavy truck

Abstract

The invention discloses a forming process of a plastic inner container of a vehicle-mounted hydrogen storage bottle of a heavy truck, and belongs to the technical field of high-pressure containers. The forming process of the plastic inner container of the vehicle-mounted hydrogen storage bottle of the heavy truck comprises the steps that thermoplastic plastic serves as a raw material, an end socket and a shell ring are obtained through an injection molding process and an extrusion process, the two ends of the shell ring are provided with first welding structures, and the end, connected with the first welding structures, of the end socket is provided with a second welding structure; coating the corresponding surfaces of the first welding structure and the second welding structure with an interface sealant, and then connecting the corresponding surfaces of the first welding structure and the second welding structure to obtain two welding surfaces; welding and sealing the two welding surfaces; and the welded workpiece is fed into a material waiting position, redundant materials are removed through cutting, and the plastic inner container of the vehicle-mounted hydrogen storage cylinder of the heavy truck is obtained. The mechanical strength of the weld joint of the plastic inner container is improved, the gas barrier property of the plastic inner container is enhanced, the weld joint has good hydrogen permeation prevention performance, and the use safety of the gas cylinder is guaranteed.

Description

Technical Field

[0001] The present application relates to a forming process for a plastic inner liner of a heavy - duty truck hydrogen storage cylinder, belonging to the technical field of high - pressure vessels. Background Art

[0002] In the field of heavy - duty truck hydrogen storage cylinders, it is usually required that the hydrogen storage cylinder has characteristics such as high pressure resistance and large capacity to meet the large demand for hydrogen in heavy - duty trucks. Type IV hydrogen storage cylinders have advantages such as light weight, high hydrogen storage density, fatigue resistance, resistance to high - temperature and high - pressure hydrogen embrittlement, and low comprehensive cost. Therefore, they have become the type of hydrogen storage cylinders that are focused on developing globally.

[0003] The plastic inner liner of a Type IV hydrogen storage cylinder plays a core role in the hydrogen storage cylinder. Therefore, there are relatively high requirements for the preparation process of the plastic inner liner. At present, the preparation process of the inner liner of a Type IV hydrogen storage cylinder is mainly divided into one - piece forming and split forming. However, restricted by the existing processing technology, it is almost impossible to process a large - aspect - ratio and large - capacity plastic inner liner in one step. The split - forming process usually requires welding treatment. The forming time is short, the impact toughness is good, and the product size is stable. However, due to the need for welding, there are disadvantages such as weld seams, resulting in a decrease in the local performance of the product. In particular, the strength is likely to be insufficient at the weld seam, leading to an increased risk of interfacial hydrogen leakage. Summary of the Invention

[0004] In order to solve the above problems, a forming process for a plastic inner liner of a heavy - duty truck hydrogen storage cylinder is provided, which improves the mechanical strength at the weld seam of the plastic inner liner, enhances its gas barrier performance, enables the weld seam to have good hydrogen - permeation - proof performance, and ensures the safety of the gas cylinder during use.

[0005] The present application provides a forming process for a plastic inner liner of a heavy - duty truck hydrogen storage cylinder, including the following steps:

[0006] (1) Using thermoplastic as raw material, obtaining a head and a cylinder section through injection molding process and extrusion process respectively. Both ends of the cylinder section have a first welding structure, and one end of the head connected to the first welding structure has a second welding structure;

[0007] (2) Coating an interface sealant on the surfaces corresponding to the first welding structure and the second welding structure, and then connecting the surfaces corresponding to the first welding structure and the second welding structure to obtain two welding surfaces;

[0008] (3) Welding and sealing the two welding surfaces, wherein heating is carried out by an infrared lamp tube with a power of 10 - 30 KW;

[0009] (4) Sending the welded workpiece to the waiting position, and removing the excess material by cutting to obtain a plastic inner liner of a heavy - duty truck hydrogen storage cylinder.

[0010] Optionally, the coating thickness of the interface sealant is 0.5 - 2 mm.

[0011] Optionally, during the welding process in step (3), the heating temperature of the infrared lamp tube is 200 - 1000 °C, and the heating time is 20 - 50 s.

[0012] Optionally, during the welding process in step (3), the heating temperature of the workpiece is 200 - 400 °C, and the heating time is 20 - 50 s.

[0013] Optionally, during the welding process in step (3), the melting depth is 1.2 - 2.5 mm, the welding pressure is 0.3 - 1 MPa, and the welding time is 2 - 6 min.

[0014] Optionally, in step (1), the thermoplastic plastic is at least one of polyamide, polyamide 6, and polyamide 12.

[0015] Optionally, in step (1), the temperature of the injection molding process is 240 - 300 °C, and the pressure is 80 - 120 MPa;

[0016] The temperature of the extrusion process is 220 - 280 °C, the pressure is 10 - 35 MPa, and the speed is 0.5 - 3 m / min.

[0017] Optionally, in step (2), the preparation method of the interface sealant includes the following steps:

[0018] S1. Heat the epoxy resin to 50 - 65 °C, then add 4 - 6 wt% of the modifier, and react for 3 - 6 h to obtain modified epoxy resin;

[0019] S2. Add polyamic acid to N-methylpyrrolidone to obtain a polyamic acid solution with a concentration of 5 - 10%, then immerse the pretreated basalt fiber in the polyamic acid solution, stir and disperse for 5 - 15 min, take it out, and then heat-treat it at 200 - 280 °C for 0.5 - 2 h to obtain modified basalt fiber;

[0020] S3. Mix the modified epoxy resin, N-methylpyrrolidone, and absolute ethanol in a mass ratio of (4 - 7):(0.5 - 2):1, and magnetically stir for 30 - 60 min, then add 17 - 25 wt% of the modified basalt fiber and 0.1 - 0.3 wt% of the defoaming agent, and continue to magnetically stir for 50 - 80 min to obtain the interface sealant.

[0021] Optionally, the epoxy resin is at least one of epoxy resin E-42, epoxy resin E-20, and epoxy resin E-51.

[0022] Optionally, in step S1, the modifier includes one or a combination of 3-isocyanatopropylmethyldimethoxysilane, 3-isocyanatopropylmethyldiethoxysilane, or 3-isocyanatopropyltriisopropoxysilane.

[0023] Optionally, in step S2, the preparation method of the pretreated basalt fiber includes the following steps:

[0024] Disperse the basalt fiber in a blast drying oven and perform constant temperature treatment at 200-350°C for 1-3 hours to obtain the pretreated basalt fiber.

[0025] Optionally, in step S2, the polyamic acid is obtained by solution polymerization of a dianhydride monomer and a diamine monomer in an organic solvent, and its solid content is 18-25 wt%.

[0026] The beneficial effects of this application include but are not limited to:

[0027] 1. The forming process of the plastic inner liner of the heavy truck vehicle-mounted hydrogen storage bottle in this application, by setting the mutually cooperating first welding structure and second welding structure, increases the contact area between the corresponding surfaces of the head and the cylinder section, so that more interface sealant can be incorporated into the connection between the two. By coating the interface sealant, during the heating welding process, the interface sealant can be fused and connected between the head and the cylinder section. Among them, the added basalt fiber can effectively increase the diffusion path of oxygen, water, and corrosive ions, reducing the film layer permeability; the polyamic acid grafted on the surface of the basalt fiber can significantly improve the thermal stability and surface roughness of the fiber, not only ensuring the mechanical strength of the basalt fiber, but also facilitating the reaction between its coating layer and epoxy resin, thereby further enhancing the interface adhesion and preventing hydrogen permeation; the modified basalt fiber and the modified epoxy resin act together to form a high-strength interface layer, effectively dispersing stress, ensuring the welding strength and tightness, and being beneficial to improving the overall structural stability and safety of the plastic inner liner of the hydrogen storage bottle. By optimizing the welding process, the temperature and melting depth of the welding end face of the inner liner are adjustable, and when used in combination with the welding structure and the interface sealant, the connection between the head and the cylinder section can be made more dense, reducing hydrogen permeation, while improving the interface bonding strength, achieving a leapfrog breakthrough in the qualification rate of the inner liner products of type IV bottles, and being particularly suitable for producing the plastic inner liner of high-pressure and large-capacity heavy truck vehicle-mounted hydrogen storage bottles.

[0028] 2. The forming process of the plastic inner liner of the heavy truck vehicle-mounted hydrogen storage bottle in this application, when modifying the epoxy resin, the hydroxyl group in the epoxy resin reacts with the isocyanate group in the modifier to generate a urethane bond with high chemical stability and mechanical strength. Although the alkoxy group in the modifier does not directly participate in the reaction during the modification process, it can be hydrolyzed to form silanol in the subsequent process, and the silanol then condenses with each other to form a -(Si-O-Si)n- network, increasing the denseness of the film layer and being able to reduce hydrogen permeation.

[0029] 3. The forming process of the plastic inner liner of the heavy - duty truck hydrogen storage cylinder in this application. High - temperature pretreatment can introduce polar groups (-OH, -COOH) onto the basalt fiber, which is beneficial to the subsequent grafting reaction. Polyamic acid contains a large number of carboxyl and amino groups, which can react with -OH and -COOH introduced onto the basalt fiber, so that the polyamic acid is coated on the surface of the basalt fiber. At the same time, since the heat treatment temperature is less than 300 °C, the imidization reaction of polyamic acid is not sufficient, thus introducing a large number of un - imidized - COOH onto the surface of the basalt fiber, thereby enhancing its surface polarity. The formation of the interfacial layer on the surface of the basalt fiber and the introduction of polar - COOH can effectively improve the interfacial adhesion of the basalt fiber - reinforced composite material, thus delaying the expansion of the weld and enhancing its fatigue resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings described herein are used to provide a further understanding of this application and form a part of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0031] Figure 1 It is a schematic structural diagram of the plastic inner liner of the heavy - duty truck hydrogen storage cylinder involved in the embodiment of this application.

[0032] Figure 2 is Figure 1 a schematic diagram of area A in [the figure] magnified 100 times.

[0033] List of components and reference numerals:

[0034] 1, cylinder section; 2, head; 3, welding surface; 4, first welding structure; 5, second welding structure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0036] For those conditions not specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For raw materials or instruments whose manufacturers are not specified, they are all conventional products that can be obtained through commercial purchase.

[0037] The defoamer used in the embodiments and comparative examples of the present invention is an organosilicon defoamer, with the trade name BYK - 085;

[0038] The solid content of the polyamic acid used in the embodiments and comparative examples of the present invention is 20 wt%.

[0039] As Figure 1 and Figure 2 shown, the present application provides a plastic inner liner for a heavy truck vehicle-mounted hydrogen storage cylinder, including a cylinder section 1 and a head 2. The two ends of the cylinder section 1 are provided with a first welding structure 4, and one end of the head 2 connected to the first welding structure 4 is provided with a second welding structure 5. The surfaces of the first welding structure 4 corresponding to the second welding structure 5 are connected to form a welding surface 3. The welding surface 3 is an arc-shaped bending surface, which can not only make the stress distribution more uniform, reduce the stress concentration at the welding joint, but also increase the welding contact area, improve the welding strength and sealing performance, thereby reducing the risk of hydrogen leakage and extending the service life of the inner liner, and is particularly suitable for the plastic inner liner of high-pressure and large-capacity hydrogen storage cylinders.

[0040] Example 1

[0041] A forming process for a plastic inner liner of a heavy truck vehicle-mounted hydrogen storage cylinder includes the following steps:

[0042] (1) Using polyamide 12 as the raw material, the head and the cylinder section are obtained by injection molding process and extrusion process respectively. The temperature of the injection molding process is 240 °C, the pressure is 120 MPa, the temperature of the extrusion process is 220 °C, the pressure is 35 MPa, and the speed is 0.5 m / min. The two ends of the cylinder section have a first welding structure, and one end of the head connected to the first welding structure has a second welding structure;

[0043] (2) Coating an interface sealant with a thickness of 0.5 mm on the surfaces of the first welding structure corresponding to the second welding structure, and then connecting the surfaces of the first welding structure corresponding to the second welding structure to obtain two welding surfaces;

[0044] (3) Welding and sealing the two welding surfaces. The welding pressure is 0.3 MPa and the welding time is 6 min. Among them, it is heated by an infrared lamp tube with a power of 30 KW, the heating temperature of the workpiece is 300 °C, the heating time is 20 s, and the melting depth is 1.2 mm;

[0045] (4) Sending the welded workpiece to the waiting position and removing the excess material by cutting to obtain a plastic inner liner for a heavy truck vehicle-mounted hydrogen storage cylinder;

[0046] In step (2), the preparation method of the interface sealant includes the following steps:

[0047] S1. Heating epoxy resin E-20 to 50 °C, and then adding 4 wt% of 3-isocyanatopropylmethyldiethoxysilane and reacting for 3 h to obtain modified epoxy resin E-20;

[0048] S2. Dispersedly place basalt fibers in a blast drying oven, and perform constant temperature treatment at 200 °C for 3 h to obtain pretreated basalt fibers. Add polyamic acid to N-methylpyrrolidone to obtain a 5% polyamic acid solution. Then immerse the pretreated basalt fibers in the polyamic acid solution, stir and disperse for 5 min. After taking out, perform heat treatment at 200 °C for 2 h to obtain modified basalt fibers;

[0049] S3. Mix modified epoxy resin E-20, N-methylpyrrolidone, and absolute ethanol according to a mass ratio of 7:2:1, and magnetically stir for 30 min. Then add 17 wt% modified basalt fibers and 0.1 wt% defoamer, and continue to magnetically stir for 50 min to obtain an interface sealant.

[0050] Example 2

[0051] A forming process for the plastic inner liner of a heavy truck-mounted hydrogen storage cylinder, comprising the following steps:

[0052] (1) Using polyamide 6 as the raw material, obtain the head and the barrel section through injection molding process and extrusion process respectively. The temperature of the injection molding process is 300 °C, the pressure is 80 MPa, the temperature of the extrusion process is 280 °C, the pressure is 10 MPa, and the speed is 3 m / min. Both ends of the barrel section have a first welding structure, and one end of the head connected to the first welding structure has a second welding structure;

[0053] (2) Coat an interface sealant with a thickness of 2 mm on the surfaces corresponding to the first welding structure and the second welding structure, and then connect the surfaces corresponding to the first welding structure and the second welding structure to obtain two welding surfaces;

[0054] (3) Perform welding and sealing on the two welding surfaces. The welding pressure is 1 MPa, and the welding time is 2 min. Among them, heat is applied through an infrared lamp tube with a power of 30 KW. The heating temperature of the workpiece is 400 °C, the heating time is 20 s, and the melting depth is 2.5 mm;

[0055] (4) Send the welded workpiece to the waiting position, and remove the excess material by cutting to obtain the plastic inner liner of the heavy truck-mounted hydrogen storage cylinder;

[0056] In step (2), the preparation method of the interface sealant includes the following steps:

[0057] S1. Heat epoxy resin E-51 to 65 °C, and then add 6 wt% 3-isocyanatopropyltriisopropoxysilane, and react for 6 h to obtain modified epoxy resin E-51;

[0058] S2. Dispersedly place basalt fibers in a blast drying oven, and perform constant temperature treatment at 350 °C for 1 h to obtain pretreated basalt fibers. Add polyamic acid to N-methylpyrrolidone to obtain a 10% polyamic acid solution. Then immerse the pretreated basalt fibers in the polyamic acid solution, stir and disperse for 15 min. After taking them out, perform heat treatment at 280 °C for 0.5 h to obtain modified basalt fibers;

[0059] S3. Mix modified epoxy resin E-51, N-methylpyrrolidone and absolute ethanol according to a mass ratio of 4:0.5:1, and magnetically stir for 60 min. Then add 25 wt% modified basalt fibers and 0.3 wt% defoamer, and continue magnetic stirring for 80 min to obtain an interface sealant.

[0060] Example 3

[0061] A forming process for a plastic inner liner of a heavy truck vehicle-mounted hydrogen storage bottle, comprising the following steps:

[0062] (1) Using polyamide as a raw material, obtain a head and a cylinder section through injection molding and extrusion processes respectively. The temperature of the injection molding process is 270 °C, the pressure is 100 MPa, the temperature of the extrusion process is 250 °C, the pressure is 22 MPa, and the speed is 1.5 m / min. Both ends of the cylinder section have a first welding structure, and one end of the head connected to the first welding structure has a second welding structure;

[0063] (2) Coat an interface sealant with a thickness of 1.2 mm on the surfaces corresponding to the first welding structure and the second welding structure, and then connect the surfaces corresponding to the first welding structure and the second welding structure to obtain two welding surfaces;

[0064] (3) Weld and seal the two welding surfaces. The welding pressure is 0.7 MPa and the welding time is 4 min. Among them, heat is applied through an infrared lamp tube with a power of 20 KW. The heating temperature of the workpiece is 300 °C, the heating time is 35 s, and the melting depth is 2 mm;

[0065] (4) Send the welded workpiece to the waiting position, and remove the excess material by cutting to obtain a plastic inner liner of a heavy truck vehicle-mounted hydrogen storage bottle;

[0066] In step (2), the preparation method of the interface sealant includes the following steps:

[0067] S1. Heat epoxy resin E-42 to 58 °C, and then add 5 wt% 3-isocyanatopropylmethyldimethoxysilane, and react for 5 h to obtain modified epoxy resin E-42;

[0068] S2. Dispersedly place basalt fibers in a blast drying oven, and carry out isothermal treatment at 280 °C for 2 h to obtain pretreated basalt fibers. Add polyamic acid to N-methylpyrrolidone to obtain a polyamic acid solution with a concentration of 8%. Then immerse the pretreated basalt fibers in the polyamic acid solution, stir and disperse for 10 min. After taking out, conduct heat treatment at 250 °C for 1.2 h to obtain modified basalt fibers;

[0069] S3. Mix modified epoxy resin E-42, N-methylpyrrolidone and absolute ethanol according to a mass ratio of 5:1:1, and magnetically stir for 50 min. Then add 20 wt% modified basalt fibers and 0.2 wt% defoamer, and continue magnetic stirring for 65 min to obtain an interface sealant.

[0070] Example 4

[0071] The difference from Example 3 is as follows:

[0072] During the welding process in step (3), the heating temperature of the workpiece is 250 °C and the heating time is 40 s.

[0073] Example 5

[0074] The difference from Example 3 is as follows:

[0075] During the welding process in step (3), the heating temperature of the workpiece is 350 °C and the heating time is 30 s.

[0076] Example 6

[0077] The difference from Example 3 is as follows:

[0078] In step (2), the preparation method of the interface sealant includes the following steps:

[0079] S1. Dispersedly place basalt fibers in a blast drying oven, and carry out isothermal treatment at 280 °C for 2 h to obtain pretreated basalt fibers. Add polyamic acid to N-methylpyrrolidone to obtain a polyamic acid solution with a concentration of 8%. Then immerse the pretreated basalt fibers in the polyamic acid solution, stir and disperse for 10 min. After taking out, conduct heat treatment at 250 °C for 1.2 h to obtain modified basalt fibers;

[0080] S2. Mix epoxy resin E-42, N-methylpyrrolidone and absolute ethanol according to a mass ratio of 5:1:1, and magnetically stir for 50 min. Then add 20 wt% modified basalt fibers and 0.2 wt% defoamer, and continue magnetic stirring for 65 min to obtain an interface sealant.

[0081] Example 7

[0082] The difference from Example 3 is as follows:

[0083] In step (2), the preparation method of the interface sealant includes the following steps:

[0084] S1. Heat epoxy resin E-42 to 58 °C, then add 5 wt% 3-isocyanatopropylmethyldimethoxysilane and react for 5 h to obtain modified epoxy resin E-42;

[0085] S2. Add polyamic acid to N-methylpyrrolidone to obtain a polyamic acid solution with a concentration of 8%, then immerse basalt fibers in the polyamic acid solution, stir and disperse for 10 min, take them out, and then perform heat treatment at 250 °C for 1.2 h to obtain modified basalt fibers;

[0086] S3. Mix the modified epoxy resin E-42, N-methylpyrrolidone, and absolute ethanol according to a mass ratio of 5:1:1, and magnetically stir for 50 min, then add 20 wt% modified basalt fibers and 0.2 wt% defoamer, and continue to magnetically stir for 65 min to obtain the interface sealant.

[0087] Example 8

[0088] The difference from Example 3 is that:

[0089] In step S2, the heat treatment temperature is 350 °C.

[0090] Comparative Example 1

[0091] A forming process for the plastic inner liner of a heavy-duty truck hydrogen storage cylinder includes the following steps:

[0092] (1) Using polyamide as the raw material, obtain the head and the cylinder section through injection molding and extrusion processes respectively. The temperature of the injection molding process is 270 °C, the pressure is 100 MPa, the temperature of the extrusion process is 250 °C, the pressure is 22 MPa, and the speed is 1.5 m / min;

[0093] (2) Coat the corresponding surfaces of the head and the cylinder section with an interface sealant with a thickness of 1.2 mm, and then connect the corresponding surfaces of the head and the cylinder section to obtain two welding surfaces;

[0094] (3) Weld and seal the two welding surfaces. The welding pressure is 0.7 MPa and the welding time is 4 min. Among them, heat is applied through an infrared lamp tube with a power of 20 KW. The heating temperature of the workpiece is 300 °C, the heating time is 35 s, and the melting depth is 2 mm;

[0095] (4) Send the welded workpiece to the waiting position and remove the excess material by cutting to obtain the plastic inner liner of the heavy-duty truck hydrogen storage cylinder;

[0096] In step (2), the preparation method of the interface sealant comprises the following steps:

[0097] S1. Heat epoxy resin E-42 to 58 °C, then add 5 wt% of 3-isocyanatopropylmethyldimethoxysilane, and react for 5 h to obtain modified epoxy resin E-42.

[0098] S2. Dispersedly place basalt fibers in a blast drying oven, and perform constant temperature treatment at 280 °C for 2 h to obtain pretreated basalt fibers. Add polyamic acid to N-methylpyrrolidone to obtain a polyamic acid solution with a concentration of 8%. Then immerse the pretreated basalt fibers in the polyamic acid solution, stir and disperse for 10 min. After taking out, perform heat treatment at 250 °C for 1.2 h to obtain modified basalt fibers.

[0099] S3. Mix the modified epoxy resin E-42, N-methylpyrrolidone, and absolute ethanol according to a mass ratio of 5:1:1, and magnetically stir for 50 min. Then add 20 wt% of modified basalt fibers and 0.2 wt% of defoamer, and continue magnetic stirring for 65 min to obtain the interface sealant.

[0100] Comparative Example 2

[0101] A forming process for the plastic inner liner of a heavy-duty truck hydrogen storage cylinder comprises the following steps:

[0102] (1) Using polyamide as the raw material, obtain the head and the cylinder section through injection molding process and extrusion process respectively. The temperature of the injection molding process is 270 °C, the pressure is 100 MPa, the temperature of the extrusion process is 250 °C, the pressure is 22 MPa, and the speed is 1.5 m / min. Both ends of the cylinder section have a first welding structure, and one end of the head connected to the first welding structure has a second welding structure.

[0103] (2) Connect the surfaces of the first welding structure corresponding to the second welding structure to obtain two welding surfaces.

[0104] (3) Weld and seal the two welding surfaces. The welding pressure is 0.7 MPa, and the welding time is 4 min. Among them, heat is applied through an infrared lamp tube with a power of 20 KW. The heating temperature of the workpiece is 300 °C, the heating time is 35 s, and the melting depth is 2 mm.

[0105] (4) Send the welded workpiece to the waiting position, and remove the excess material by cutting to obtain the plastic inner liner of the heavy-duty truck hydrogen storage cylinder.

[0106] For the above-mentioned embodiments and comparative examples, there is no specific limitation on the heating temperature and heating time of the infrared lamp tube, as long as the workpiece can reach the target temperature and be heated for a specific time.

[0107] Tensile and impact mechanical test specimens were prepared circumferentially at two welds. The thickness of the specimens was 2.5 mm, and mechanical property tests were carried out. The results were taken as the average of the two welds.

[0108] There is no domestic testing institution for measuring hydrogen permeability. Since the molecular diameter of helium is only second to that of hydrogen, the helium permeability of the specimens was measured by a differential pressure gas permeation instrument to evaluate the gas barrier performance of the specimens. The results were taken as the average of the two welds.

[0109] The test results of the specimens at the welds of the plastic inner liners in Examples 1-8 and Comparative Examples 1-2 are shown in Table 1.

[0110] Table 1

[0111]

[0112] As mentioned above, only the embodiments of the present application are described. The protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the technical idea and principle of the present application shall be included within the protection scope of the present application.

Claims

1. A molding process for a plastic liner of a heavy truck-mounted hydrogen storage bottle, characterized in that: The following steps are involved: (1) A head and a barrel section are obtained by injection molding and extrusion respectively using thermoplastic plastic as raw material, both ends of the barrel section have a first welding structure, and one end of the head connected to the first welding structure has a second welding structure; (2) coating an interface sealant on the surfaces corresponding to the first welding structure and the second welding structure, and then connecting the surfaces corresponding to the first welding structure and the second welding structure to obtain two welding surfaces; (3) Welding and sealing the two welding surfaces, wherein heating is performed by an infrared lamp tube with a power of 10-30 kW; (4) The welded workpiece is sent to the material waiting position, and the excess material is removed by cutting to obtain the plastic liner of the heavy truck-mounted hydrogen storage bottle.

2. The molding process of the plastic liner of the heavy truck hydrogen storage bottle according to claim 1 is characterized in that: During the welding process of step (3), the heating temperature of the infrared lamp tube is 200-1000° C. and the heating time is 20-50 seconds.

3. The molding process of the plastic liner of the heavy truck hydrogen storage bottle according to claim 1 is characterized in that: During the welding process of step (3), the heating temperature of the workpiece is 200-400° C. and the heating time is 20-50 s.

4. The molding process of the plastic liner of the heavy truck hydrogen storage bottle according to claim 1 is characterized in that: During the welding process of step (3), the melting depth is 1.2-2.5 mm, the welding pressure is 0.3-1 MPa, and the welding time is 2-6 min.

5. The molding process of the plastic liner of the hydrogen storage bottle for heavy trucks according to claim 1 is characterized in that: In step (1), the thermoplastic plastic is at least one of polyamide, polyamide 6 and polyamide 12.

6. The molding process of the plastic liner of the hydrogen storage bottle for heavy trucks according to claim 1 is characterized in that: In step (1), the temperature of the injection molding process is 240-300° C. and the pressure is 80-120 MPa; The temperature of the extrusion process is 220-280°C, the pressure is 10-35MPa, and the speed is 0.5-3m / min.

7. The molding process of the plastic liner of the heavy truck hydrogen storage bottle according to claim 1 is characterized in that: In step (2), the method for preparing the interface sealant comprises the following steps: S1, heating the epoxy resin to 50-65°C, adding 4-6wt% of a modifier, and reacting for 3-6h to obtain a modified epoxy resin; S2, adding polyamic acid to N-methylpyrrolidone to obtain a polyamic acid solution with a concentration of 5-10%, then immersing the pretreated basalt fiber in the polyamic acid solution, stirring and dispersing for 5-15 minutes, taking it out, and then heat treating it at 200-280° C. for 0.5-2 hours to obtain modified basalt fiber; S3. The modified epoxy resin, N-methylpyrrolidone and anhydrous ethanol are mixed in a mass ratio of (4-7): (0.5-2): 1, and magnetically stirred for 30-60 minutes, and then 17-25wt% of modified basalt fiber and 0.1-0.3wt% of defoaming agent are added, and the magnetic stirring is continued for 50-80 minutes to obtain an interface sealant.

8. The molding process of the plastic liner of the hydrogen storage bottle for heavy trucks according to claim 7 is characterized in that: In step S1, the modifier includes one or a combination of 3-isocyanate propyl methyl dimethoxy silane, 3-isocyanate propyl methyl diethoxy silane or 3-isocyanate propyl triisopropoxy silane.

9. The molding process of the plastic liner of the hydrogen storage bottle for heavy trucks according to claim 7 is characterized in that: In step S2, the method for preparing the pretreated basalt fiber comprises the following steps: The basalt fibers are dispersed and placed in a blast oven, and are treated at a constant temperature of 200-350° C. for 1-3 hours to obtain pretreated basalt fibers.

10. The molding process of the plastic liner of the hydrogen storage bottle for heavy trucks according to claim 7 is characterized in that: In step S2, the polyamic acid is obtained by solution polymerization of dianhydride monomers and diamine monomers in an organic solvent, and the solid content thereof is 18-25 wt%.

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