A plastic liner carbon fiber fully wrapped composite gas cylinder and its preparation method

Abstract

The present invention provides a plastic liner carbon fiber fully wrapped composite gas cylinder and a preparation method thereof, and relates to the technical field of hydrogen storage gas cylinders. The plastic liner carbon fiber fully wrapped composite gas cylinder of the present invention is made of carbon fiber impregnated with an impregnation slurry, which is alternately wound by spiral winding and annular winding, wherein the single layer thickness of the annular winding layer and the spiral winding layer are both 0.35 to 0.38 mm, the number of layers of the annular winding layer is 30 to 32 layers, and the number of layers of the spiral winding layer is 34 to 36 layers. Compared with the existing metal liner fully wrapped gas cylinder, this gas cylinder avoids the problem of hydrogen embrittlement of the liner when storing hydrogen. Compared with the plastic liner fiber fully wrapped gas cylinder, this gas cylinder reduces the thickness while improving the load-bearing capacity, thereby reducing the weight of the gas cylinder, and has high air tightness, good interface bonding, and high fatigue life.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen storage cylinders, and in particular relates to a plastic liner carbon fiber fully wrapped composite cylinder and a preparation method thereof. Background Art

[0002] In recent years, hydrogen has garnered widespread attention as a clean energy source, and hydrogen storage technology has also developed accordingly. There are four main types of hydrogen storage cylinders: Type I all-metal cylinders, Type II metal liner fiber-wrap cylinders, Type III metal liner fiber-wrap cylinders, and Type IV plastic liner fiber-wrap cylinders.

[0003] With the development of hydrogen storage cylinders, Type I and Type II cylinders are gradually being replaced by Type III and Type IV cylinders. The current manufacturing process for Type III and Type IV cylinders is mainly as follows: carbon fiber tow is impregnated with epoxy resin, then longitudinally and circumferentially wrapped around an aluminum alloy or plastic liner. The cylinders are then cured and molded before demolding. Metal liner fiber-wrapped cylinders have advantages such as a high bulk-to-weight ratio and corrosion resistance. However, when storing hydrogen, the liner is prone to hydrogen embrittlement. Furthermore, there is a potential difference between the aluminum liner and the carbon fiber layer in Type III cylinders, making direct contact prone to corrosion. Therefore, an anti-galvanic corrosion layer is required between the aluminum liner and the carbon fiber wrapping layer, increasing the weight of the cylinder. The plastic liner of a Type IV cylinder is generally made of polymer materials such as polyamide PA6 and high-density polyethylene (HDPE), while the wrapping layer is generally made of carbon fiber or glass fiber. The different types of these two materials result in poor interfacial bonding between the liner and the outer layer, and peeling and delamination are prone to occur at the joint, leading to leakage. In addition, in order to improve the quality of hydrogen storage, the internal pressure needs to be increased, so the radius and wall thickness of the gas cylinder need to be increased. The mass of the gas cylinder increases, and the increase in hydrogen storage density is therefore limited. Reducing the wall thickness will bring the risk of gas leakage.

[0004] Therefore, it is necessary to improve the existing plastic liner carbon fiber fully wrapped composite gas cylinder. Summary of the Invention

[0005] The purpose of the present invention is to address the deficiencies of the prior art and provide a plastic liner carbon fiber fully wrapped composite gas cylinder and a preparation method thereof, which at least solves some of the problems existing in the prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] A plastic liner carbon fiber fully wound composite gas cylinder, comprising a plastic liner, a valve seat, and a composite material winding layer, wherein the composite material winding layer is coated on the outside of the plastic liner; the composite material winding layer is formed by alternating spiral winding and annular winding of carbon fibers impregnated with an impregnation slurry;

[0008] The thickness of each single layer of the annular winding layer and the spiral winding layer is 0.35-0.38 mm, the number of layers of the annular winding layer is 30-32, and the number of layers of the spiral winding layer is 34-36.

[0009] Furthermore, the winding angle of the spiral winding layer is 30 to 37 degrees; and the angle of the annular winding layer is 88 to 90 degrees.

[0010] Furthermore, the material of the composite winding layer is composed of carbon fiber and impregnation slurry in a mass ratio of 10: (1 to 1.8); wherein,

[0011] The impregnation slurry comprises the following raw materials in parts by weight: 55-70 parts of epoxy resin, 10-20 parts of isophorone diisocyanate, 3.4-5 parts of dithiol compound, 3-5 parts of long-chain alkyl modified silane coupling agent, 5-8 parts of curing agent, and 1-3 parts of accelerator.

[0012] Preferably, the impregnation slurry comprises the following raw materials in parts by weight: 67 parts of epoxy resin, 17 parts of isophorone diisocyanate, 4.2 parts of bismercapto compound, 4.3 parts of long-chain alkyl-modified silane coupling agent, 6 parts of curing agent, and 2 parts of accelerator.

[0013] Furthermore, the linear density of the carbon fiber is 1.5 to 1.7 g / m.

[0014] Furthermore, the bismercapto compound is ethylene glycol bismercaptoacetate or 2,3-dimercaptosuccinic acid.

[0015] Furthermore, the long-chain alkyl modified silane coupling agent is prepared by modifying a bisaminosilane coupling agent with a C8-C12 saturated / unsaturated fatty acid ester.

[0016] Preferably, the bisaminosilane coupling agent is selected from any one of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane KH-792, N-aminoethyl-γ-aminopropyltriethoxysilane KH-791, and N-(β-aminoethyl)-γ-aminopropylmethyl-dimethoxysilane KH-602.

[0017] Preferably, the C8-C12 saturated / unsaturated fatty acid ester is prepared by reacting a straight-chain or branched saturated or unsaturated fatty acid with ethanol, propanol or butanol.

[0018] Preferably, the reaction molar ratio of the bisaminosilane coupling agent to the saturated / unsaturated fatty acid ester is 1:(1-1.1).

[0019] Preferably, the long-chain alkyl-modified silane coupling agent is prepared by the following method:

[0020] Mix the bisaminosilane coupling agent with n-butanol, then add saturated / unsaturated fatty acid ester, reflux at 75-85°C for 3-5h, distill, and cool to room temperature to obtain a long-chain alkyl modified silane coupling agent.

[0021] Preferably, the curing agent is selected from any one or more of diaminodiphenylmethane, m-phenylenediamine, diaminodiphenyl sulfone, methylenebisphenylenediamine, and hexamethylenetetramine.

[0022] Preferably, the accelerator is selected from any one of an amine accelerator and a tin accelerator, including but not limited to triethylenediamine, dibutyltin dilaurate, and stannous octoate.

[0023] Another aspect of the present invention provides a method for preparing a plastic liner carbon fiber fully wrapped composite gas cylinder, comprising the following steps:

[0024] (1) impregnating carbon fiber in an impregnation slurry and then winding the carbon fiber around a plastic liner to form a composite material winding layer;

[0025] (2) placing the plastic liner wrapped with the composite material layer into a curing furnace for curing, thereby obtaining the plastic liner carbon fiber fully wrapped composite gas cylinder.

[0026] Furthermore, in step (2), the curing temperature is 95-115° C. and the curing time is 3-5 hours.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. Compared with existing metal liner fully wrapped gas cylinders, the plastic liner carbon fiber fully wrapped composite gas cylinder provided by the present invention avoids the problem of hydrogen embrittlement of the liner when storing hydrogen. Compared with plastic liner fiber fully wrapped gas cylinders, it improves the load-bearing capacity while reducing the thickness, achieving a reduction in the weight of the gas cylinder, and has high air tightness and long fatigue life.

[0029] 2. The plastic liner carbon fiber fully wrapped composite gas cylinder provided by the present invention designs the composite material winding layer into two winding methods and reasonably designs the thickness of the winding layer, which is beneficial to improving the uniform load-bearing of the gas cylinder body. While improving the load-bearing capacity, the thickness of the winding layer can be reduced, thereby reducing the weight of the gas cylinder; it also has a significant inhibitory effect on the expansion of cracks in the bottle body, thereby more effectively preventing hydrogen penetration and improving air tightness.

[0030] 3. The plastic liner carbon fiber fully wrapped composite gas cylinder provided by the present invention optimizes the formula of the impregnation slurry, adds isophorone diisocyanate, long-chain alkyl modified silane coupling agent and dithiol compound to the slurry, introduces highly reactive groups such as isocyanate, and can form an interpenetrating cross-linked network with the epoxy resin, which can prevent the hydrogen in the plastic liner from diffusing outward and significantly reduce the hydrogen leakage rate of the gas cylinder; compared with conventional silane coupling agents, the long-chain alkyl modified silane coupling agent is easier to interact, entangle or interpenetrate with the cross-linked network, thereby forming a dense protective layer and increasing air tightness; the three work together to greatly improve air tightness while also helping to improve load-bearing capacity, improve fatigue resistance and extend service life. DETAILED DESCRIPTION

[0031] The following non-limiting examples are provided to enable those skilled in the art to more fully understand the present invention, but are not intended to limit the present invention in any way. The following is merely an illustrative description of the scope of the present invention, and those skilled in the art may make various changes and modifications to the present invention based on the disclosed content, which should also fall within the scope of the present invention.

[0032] The present invention is further described below by way of specific examples. Unless otherwise specified, the various chemical reagents used in the examples of the present invention were obtained through conventional commercial channels.

[0033] Example 1

[0034] A plastic liner carbon fiber fully wrapped composite gas cylinder, comprising:

[0035] A plastic liner, a valve seat and a composite material winding layer, wherein the composite material winding layer is coated on the outside of the plastic liner;

[0036] The composite winding layer is made of carbon fiber impregnated with impregnation slurry through alternating spiral winding and annular winding, wherein the single layer thickness of the annular winding layer and the spiral winding layer is 0.350 mm; the number of layers of the annular winding layer is 30, and the winding angle is 88°; the number of layers of the spiral winding layer is 36, and the winding angle is 30°.

[0037] A method for preparing a composite gas cylinder with a plastic liner and fully wrapped carbon fiber comprises the following steps:

[0038] (1) Carbon fiber (linear density 1.65 g / m) was impregnated in an impregnation slurry to obtain a prepreg (the mass ratio of carbon fiber to impregnation slurry in the prepreg was 10:1), and then the prepreg was wound on a plastic liner (thickness 5 mm) to form a composite winding layer;

[0039] In this embodiment, the impregnation slurry contains the following raw materials: 55 parts of epoxy resin, 10 parts of isophorone diisocyanate, 3.4 parts of ethylene glycol bis(thioglycolate), 3 parts of long-chain alkyl-modified silane coupling agent, 5 parts of curing agent, and 1 part of accelerator; wherein,

[0040] The long-chain alkyl modified silane coupling agent was prepared by the following method: 1 mol of KH-791 was mixed with 0.5 mol of n-butanol, and then 1 mol of propyl octanoate was added, and the mixture was refluxed at 75° C. for 5 h, distilled, and cooled to room temperature to obtain the obtained product.

[0041] (2) Curing molding

[0042] The plastic liner wrapped with the composite material layer is placed in a curing oven for curing at a temperature of 95° C. for 5 hours to obtain the plastic liner carbon fiber fully wrapped composite gas cylinder.

[0043] Example 2

[0044] Another plastic liner carbon fiber fully wrapped composite gas cylinder, comprising:

[0045] A plastic liner, a valve seat and a composite material winding layer, wherein the composite material winding layer is coated on the outside of the plastic liner;

[0046] The composite material winding layer is made of carbon fiber impregnated with impregnation slurry through alternating spiral winding and annular winding, wherein the single layer thickness of the annular winding layer and the spiral winding layer is 0.368mm; the number of layers of the annular winding layer is 32, and the winding angle is 90°; the number of layers of the spiral winding layer is 34, and the winding angle is 37°.

[0047] Another method for preparing a plastic liner carbon fiber fully wrapped composite gas cylinder comprises the following steps:

[0048] (1) Carbon fiber (linear density 1.65 g / m) was impregnated into an impregnation slurry to obtain a prepreg (the mass ratio of carbon fiber to impregnation slurry in the prepreg was 10:1.5), and then the prepreg was wound on a plastic liner (thickness 5 mm) to form a composite winding layer;

[0049] In this embodiment, the impregnation slurry contains the following raw materials: 67 parts of epoxy resin, 17 parts of isophorone diisocyanate, 4.2 parts of 2,3-dimercaptosuccinic acid, 4.3 parts of long-chain alkyl-modified silane coupling agent, 6 parts of curing agent, and 2 parts of accelerator; wherein,

[0050] The long-chain alkyl modified silane coupling agent was prepared by the following method: 1 mol of KH-602 was mixed with 0.5 mol of n-butanol, and then 1 mol of n-butyl dodecanoate was added, and the mixture was refluxed at 80° C. for 4 h, distilled, and cooled to room temperature to obtain the obtained product.

[0051] (2) Curing molding

[0052] The plastic liner of the wound composite material wound layer is placed in a curing furnace for curing at a temperature of 105° C. for 4 hours to obtain the plastic liner carbon fiber fully wound composite gas cylinder.

[0053] Example 3

[0054] Another plastic liner carbon fiber fully wrapped composite gas cylinder, comprising:

[0055] A plastic liner, a valve seat and a composite material winding layer, wherein the composite material winding layer is coated on the outside of the plastic liner;

[0056] The composite material winding layer is made of carbon fiber impregnated with impregnation slurry through alternating spiral winding and annular winding, wherein the single layer thickness of the annular winding layer and the spiral winding layer is 0.380 mm; the number of layers of the annular winding layer is 32, and the winding angle is 90°; the number of layers of the spiral winding layer is 34, and the winding angle is 37°.

[0057] Another method for preparing a plastic liner carbon fiber fully wrapped composite gas cylinder comprises the following steps:

[0058] (1) Carbon fiber (linear density 1.65 g / m) was impregnated into an impregnation slurry to obtain a prepreg (the mass ratio of carbon fiber to impregnation slurry in the prepreg was 10:1.8), and then the prepreg was wound on a plastic liner (thickness 5 mm) to form a composite winding layer;

[0059] In this embodiment, the impregnation slurry contains the following raw materials: 70 parts of epoxy resin, 20 parts of isophorone diisocyanate, 5 parts of 2,3-dimercaptosuccinic acid, 5 parts of long-chain alkyl-modified silane coupling agent, 8 parts of curing agent, and 3 parts of accelerator; wherein,

[0060] The long-chain alkyl modified silane coupling agent was prepared by the following method: 1 mol of KH-792 was mixed with 0.5 mol of n-butanol, and then 1 mol of ethyl tridecanoate was added, and the mixture was refluxed at 85° C. for 3 h, distilled, and cooled to room temperature to obtain the obtained product.

[0061] (2) Curing molding

[0062] The plastic liner wrapped with the composite material layer is placed in a curing oven for curing at a temperature of 115° C. for 3 hours to obtain the plastic liner carbon fiber fully wrapped composite gas cylinder.

[0063] Example 4

[0064] The difference between this embodiment and embodiment 2 is that the long-chain alkyl-modified silane coupling agent in the impregnation slurry is different. The specific preparation method is as follows: 1 mol of KH-602 is mixed with 0.5 mol of n-butanol, and then 1 mol of butyl heptanoate is added, and the mixture is refluxed at 80°C for 4 hours, distilled, and cooled to room temperature to obtain the product.

[0065] Example 5

[0066] The difference between this embodiment and embodiment 2 is that the long-chain alkyl-modified silane coupling agent in the impregnation slurry is different. The specific preparation method is as follows: 1 mol of KH-602 is mixed with 0.5 mol of n-butanol, and then 1 mol of n-butyl octadecanoate is added, and the mixture is refluxed at 80°C for 4 hours, distilled, and cooled to room temperature to obtain the product.

[0067] Example 6

[0068] The difference between this embodiment and embodiment 2 is that the long-chain alkyl-modified silane coupling agent in the impregnation slurry is replaced by an equal amount of KH-602.

[0069] Example 7

[0070] The difference between this embodiment and embodiment 2 is that the impregnation slurry is different. In the impregnation slurry of this embodiment, no long-chain alkyl-modified silane coupling agent is added.

[0071] Example 8

[0072] The difference between this embodiment and embodiment 2 is that the impregnation slurry is different. In the impregnation slurry of this embodiment, no isophorone diisocyanate is added.

[0073] Example 9

[0074] The difference between this embodiment and embodiment 2 is that the impregnation slurry is different. In the impregnation slurry of this embodiment, 2,3-dimercaptosuccinic acid is not added.

[0075] Comparative Example 1

[0076] The difference between this embodiment and embodiment 2 is that the thicknesses of the spirally wound layer and the annular wound layer are different. In this comparative example, the number of the annular wound layer is 29 layers, and the number of the spirally wound layer is 37 layers.

[0077] Comparative Example 2

[0078] The difference between this embodiment and embodiment 2 is that the thicknesses of the spirally wound layer and the annular wound layer are different. In this comparative example, the number of layers of the annular wound layer is 33, and the number of layers of the spirally wound layer is 33.

[0079] Comparative Example 3

[0080] The difference between this embodiment and embodiment 2 is that the composite material winding layer is only a spiral winding layer, the number of winding layers is 66, and the thickness of a single layer is 0.368 mm.

[0081] Comparative Example 4

[0082] The difference between this embodiment and embodiment 2 is that the composite material winding layer is only an annular winding layer, the number of winding layers is 66, and the thickness of a single layer is 0.368 mm.

[0083] Test example

[0084] The plastic-lined, carbon fiber-wrapped composite gas cylinders obtained in the above examples and comparative examples were tested for hydrogen permeability, minimum burst pressure, and fatigue life. The hydrogen permeability was tested in accordance with GB / T 42610-2023, while the minimum burst pressure and fatigue life were tested in accordance with GB / T 42612-2023.

[0085] The test results are shown in Table 1 below.

[0086] Table 1

[0087] Group Minimum burst pressure (MPa) <![CDATA[Hydrogen Permeability Coefficient cm 3 ·cm / (cm 2 ·s·Pa)]]> Number of cycles (times) Example 1 176 <![CDATA[1.4×10 -15 ]]> 48278 Example 2 179 <![CDATA[0.9×10 -15 ]]> 48605 Example 3 178 <![CDATA[1.1×10 -15 ]]> 48477 Example 4 165 <![CDATA[5.8×10 -15 ]]> 46233 Example 5 168 <![CDATA[5.1×10 -15 ]]> 45261 Example 6 166 <![CDATA[5.5×10 -15 ]]> 43365 Example 7 165 <![CDATA[6.0×10 -15 ]]> 42860 Example 8 162 <![CDATA[7.6×10 -15 ]]> 44171 Example 9 168 <![CDATA[6.6×10 -15 ]]> 43510 Comparative Example 1 161 <![CDATA[3.8×10 -15 ]]> 45635 Comparative Example 2 175 <![CDATA[2.1×10 -15 ]]> 46078 Comparative Example 3 163 <![CDATA[3.8×10 -15 ]]> 46906 Comparative Example 4 164 <![CDATA[3.6×10 -15 ]]> 45606

[0088] The results show that the minimum bursting pressure of the plastic liner and carbon fiber fully wrapped composite gas cylinders obtained in Examples 1-3 of the present invention reaches 176 MPa or above, which meets the requirements; the hydrogen permeability coefficient is small and the air tightness is good, that is, the interface bonding between the composite material wrapping layer and the plastic liner is good; the gas cylinder is cyclically inflated at 70 MPa until the gas cylinder leaks, and the measured number of cycles is more than 48,000 times, and the fatigue life is high.

[0089] The minimum bursting pressure of the gas cylinders obtained in Comparative Examples 1 and 2 is significantly lower than that in Example 2, indicating that by controlling the thickness of the spiral winding layer and the annular winding layer, the thickness of the winding layer can be reduced as much as possible while maintaining a high load-bearing capacity and good airtightness of the gas cylinder, thereby reducing the weight of the gas cylinder.

[0090] The minimum bursting pressure, air tightness, and number of cycles of the gas cylinders obtained in Examples 4-8 are all lower than those in Example 2, indicating that the composition of the impregnation slurry has a great influence on the performance of the gas cylinder. The use of the impregnation slurry provided by the present invention helps to improve the carrying capacity, air tightness, interface bonding, and service life of the gas cylinder.

[0091] The above description of the embodiments is intended to facilitate understanding and application of the invention by those skilled in the art. It will be apparent that those skilled in the art can readily make various modifications to these embodiments and apply the general principles described herein to other embodiments without requiring inventive effort. Therefore, the present invention is not limited to the above-described embodiments. Improvements and modifications made by those skilled in the art based on the disclosure of the present invention, without departing from the scope of the present invention, should be within the scope of protection of the present invention.

Claims

1. A plastic liner carbon fiber fully wrapped composite gas cylinder, characterized in that: The invention comprises a plastic liner, a valve seat and a composite material winding layer, wherein the composite material winding layer is coated on the outside of the plastic liner; the composite material winding layer is formed by alternating spiral winding and annular winding of carbon fibers impregnated with an impregnation slurry, wherein the thickness of each single layer of the annular winding layer and the spiral winding layer is 0.35 to 0.38 mm, the number of layers of the annular winding layer is 30 to 32, and the number of layers of the spiral winding layer is 34 to 36; The impregnation slurry comprises the following raw materials in parts by weight: 55-70 parts of epoxy resin, 10-20 parts of isophorone diisocyanate, 3.4-5 parts of dithiol compound, 3-5 parts of long-chain alkyl modified silane coupling agent, 5-8 parts of curing agent, and 1-3 parts of accelerator.

2. The plastic liner carbon fiber fully wrapped composite gas cylinder according to claim 1, characterized in that: The winding angle of the spiral winding layer is 30-37°; the angle of the annular winding layer is 88-90°.

3. The plastic liner carbon fiber fully wrapped composite gas cylinder according to claim 1, characterized in that: The material of the composite material winding layer consists of carbon fiber and impregnation slurry in a mass ratio of 10:(1-1.8).

4. The plastic liner carbon fiber fully wrapped composite gas cylinder according to claim 1, characterized in that: The impregnation slurry comprises the following raw materials in parts by weight: 67 parts of epoxy resin, 17 parts of isophorone diisocyanate, 4.2 parts of bismercapto compound, 4.3 parts of long-chain alkyl-modified silane coupling agent, 6 parts of curing agent, and 2 parts of accelerator.

5. The plastic liner carbon fiber fully wrapped composite gas cylinder according to claim 1, characterized in that: The bismercapto compound is ethylene glycol bismercaptoacetate or 2,3-dimercaptosuccinic acid.

6. The plastic liner carbon fiber fully wrapped composite gas cylinder according to claim 1, characterized in that: The long-chain alkyl modified silane coupling agent is prepared by modifying a bisaminosilane coupling agent with C8-C12 saturated / unsaturated fatty acid ester.

7. The plastic liner carbon fiber fully wrapped composite gas cylinder according to claim 6, characterized in that: The bisaminosilane coupling agent is selected from any one of KH-792, KH-791 and KH-602.

8. The plastic liner carbon fiber fully wrapped composite gas cylinder according to claim 6, characterized in that: The C8-C12 saturated / unsaturated fatty acid ester is prepared by reacting a straight-chain or branched saturated or unsaturated fatty acid with ethanol, propanol or butanol.

9. The method for preparing a plastic liner carbon fiber fully wrapped composite gas cylinder according to any one of claims 1 to 8, characterized in that: The following steps are involved: (1) impregnating carbon fiber in an impregnation slurry and then winding the carbon fiber around a plastic liner to form a composite material winding layer; (2) placing the plastic liner wrapped with the composite material layer into a curing furnace for curing, thereby obtaining the plastic liner carbon fiber fully wrapped composite gas cylinder.

10. The method for preparing a plastic liner carbon fiber fully wrapped composite gas cylinder according to claim 9, characterized in that: The curing temperature is 95-115° C. and the curing time is 3-5 hours.