Epoxy resin composition for winding layer of IV-type hydrogen storage bottle as well as preparation method and application of epoxy resin composition

Abstract

The invention provides an epoxy resin composition for a winding layer of an IV type hydrogen storage bottle as well as a preparation method and application of the epoxy resin composition. The epoxy resin composition comprises the following components: epoxy resin, a diluent, a curing agent and an accelerant, the epoxy resin is liquid epoxy resin. The formula system is small in viscosity, the reaction is slow at normal temperature, and the requirement of the winding process for the pot life can be met. The curing temperature required by the epoxy resin system is not higher than the softening temperature of the polyethylene liner. And the glass transition temperature of the cured product is higher than the standard requirement. The impact strength of a cured product obtained after the epoxy resin system pouring body is cured is also greatly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen storage, and more particularly to an epoxy resin composition for a winding layer of a type IV hydrogen storage bottle, and a preparation method and application thereof. Background Art

[0002] Hydrogen mainly appears in the form of chemical compounds on Earth. It is the most widely distributed substance in the universe. It constitutes 75% of the mass of the universe and is a secondary energy source. Hydrogen has the characteristics of high combustion calorific value, which is 3 times that of gasoline, 3.9 times that of alcohol, and 4.5 times that of coke. The product of hydrogen combustion is water, which is the cleanest energy in the world. Hydrogen energy will become an important energy source on the world energy stage. The hydrogen energy industry chain can be divided into three major links: hydrogen energy production, hydrogen energy storage and transportation, and hydrogen energy application. Among them, the storage and transportation link is the key to the efficient use of hydrogen energy and an important link that affects the large-scale development of hydrogen energy. Hydrogen storage is a bridge connecting hydrogen production and hydrogen use, and plays an irreplaceable role in the development of hydrogen energy.

[0003] Hydrogen storage cylinders generally include four types: Type I cylinders are made of all steel, with a pressure resistance of no more than 30MPa. The main disadvantage is that they are heavy and not suitable for vehicle use, but can be placed in hydrogen refueling stations as fixed hydrogen storage. Type II and Type III cylinders are metal liner wrapped with carbon fiber, which are also relatively heavy, but lighter than Type I cylinders, and the pressure resistance can be increased to 70MPa. Type IV cylinders are plastic liner wrapped with carbon fiber, with the lightest weight, suitable for vehicle use, and a gas storage pressure of 70MPa. It is the mainstream technology route abroad and has been widely used internationally.

[0004] The biggest change of Type IV bottle compared to Type III bottle is that the aluminum alloy liner is replaced by a plastic liner. The change of the liner material requires consideration of the heat resistance of the material. The heat resistance involves the following three aspects: one is the plastic liner material itself, whose maximum working temperature must be higher than the limit temperature caused by inflation and deflation. One is the heat resistance temperature of the composite material wrapping layer that wraps the liner. For safety reasons, its glass transition temperature must be at least 30°C higher than the limit temperature caused by inflation and deflation. Another thing to consider is the curing temperature of the wrapping layer, which must be lower than the working temperature of the plastic liner. If the curing temperature is too high, the plastic liner will deform, posing a safety hazard.

[0005] On October 8, 2020, the group standard "Carbon Fiber Fully Wrapped Gas Cylinders with Plastic Liners for Compressed Hydrogen for Vehicles" was officially implemented. This standard mainly stipulates the types, parameters, technical indicators and other requirements of carbon fiber fully wrapped gas cylinders with plastic liner for compressed hydrogen for vehicles, such as the nominal working pressure not exceeding 70MPa, the nominal volume not exceeding 450L, the storage medium is compressed hydrogen, and the working temperature is not lower than -40℃ and not higher than 85℃. Considering that gas cylinders may involve high-temperature working environments, the U.S. Department of Transportation's DOTCFFC2007 standard clearly requires that gas cylinders need to withstand 20 thermal cycle tests at -51.6 to 93.3℃, ​​and if the glass transition temperature of the resin system is lower than 102℃, high-temperature creep tests are required. If 93.3℃ is regarded as the working temperature, from the perspective of materials science, the glass transition temperature must be at least 30℃ higher than the working temperature to meet the use requirements. Taking all factors into consideration, the glass transition temperature of the composite wrapping layer of the gas cylinder must be at least higher than 115℃.

[0006] The current problem is that the curing temperature of the winding layer cannot be high, but the heat resistance temperature must be high. The composite winding layer is composed of a resin matrix and fibers. The resin matrix material used in the gas cylinder is an epoxy resin system. The heat resistance problem of the winding layer is the heat resistance problem of the epoxy resin system. Generally speaking, the higher the temperature required for epoxy resin curing, the higher its glass transition temperature. For example, when phthalic anhydride curing agent cures bisphenol A epoxy resin, the curing temperature is about 160°C, and the T g Around 130°C. The lower the temperature required for curing, the lower the glass transition temperature. For example, when aliphatic amine curing agents cure bisphenol A epoxy resin, curing reactions can occur at room temperature, but the T g Around 50℃.

[0007] On the other hand, it is important to consider that epoxy resin systems with high curing temperatures have poor toughness. Insufficient toughness of the matrix resin will deteriorate the impact resistance of the entire composite wrapping layer, resulting in safety accidents after collisions or bumps. In practice, toughening agents are generally used to improve the toughness of epoxy resins. Liquid rubber toughening and polyurethane toughening are commonly used toughening methods, but while improving toughness, the glass transition temperature is also greatly reduced.

[0008] In summary, the curing temperature of the epoxy resin system cannot be higher than 100°C, but the glass transition temperature must be higher than 115°C. Summary of the invention

[0009] In order to solve the above problems existing in the prior art, the present invention provides an epoxy resin composition for a winding layer of a type IV hydrogen storage bottle, and specifically relates to an epoxy resin composition for a winding layer of a type IV hydrogen storage bottle, and a preparation method and application thereof.

[0010] After long-term and in-depth research, the inventors found that increasing the amount of epoxy resin curing accelerator added to a certain extent can not only significantly reduce the curing temperature of the resin, but also improve the impact strength of the cured product.

[0011] The resin formula system of the present invention has low viscosity and slow reaction at room temperature, and can meet the application period requirements of the winding process.

[0012] The resin formulation system of the present invention can meet the requirements for heat resistance during the production and use of hydrogen storage bottles.

[0013] One of the purposes of the present invention is to provide an epoxy resin composition for a winding layer of a type IV hydrogen storage bottle, which may include the following components: an epoxy resin, a diluent, a curing agent, and an accelerator.

[0014] The epoxy resin is a liquid epoxy resin, which can be selected from at least one of liquid bisphenol A epoxy resin, liquid hydrogenated bisphenol A epoxy resin, liquid bisphenol F epoxy resin, liquid glycidyl ester epoxy resin, and liquid glycidyl amine epoxy resin. Preferably, it is at least one of liquid bisphenol A epoxy resin and liquid bisphenol F epoxy resin.

[0015] The diluent may be an inactive diluent, an active diluent, or a combination thereof.

[0016] The inactive diluent does not contain an epoxy group, and can be selected from at least one of acetone, ethanol, toluene, xylene, ethyl acetate, dibutyl phthalate, dioctyl phthalate, styrene, diallyl phthalate, and benzyl alcohol. And / or,

[0017] The reactive diluent may contain a low-viscosity substance having at least one epoxy group; the reactive diluent may be selected from at least one of polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, butyl glycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, furanmethyl glycidyl ether, ethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, o-cresyl glycidyl ether, benzyl glycidyl ether, resorcinol diglycidyl ether, octyl glycidyl ether, carbon 12-14 alkyl glycidyl ether (AGE), tert-butyl glycidyl ether, neodecanoic acid glycidyl ether, and methacrylate glycidyl ether.

[0018] The diluent is preferably one of benzyl alcohol (BA), 1,4-butanediol diglycidyl ether (622), and carbon 12-14 alkyl glycidyl ether (AGE), or a combination thereof;

[0019] The amount of the diluent used is preferably 3-15wt% of the weight of the epoxy resin, more preferably 5-10wt% (such as 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt% or any value between the above values ​​or a numerical range between any two of the above values).

[0020] The curing agent may be selected from anhydride curing agents or amine curing agents;

[0021] The acid anhydride curing agent can be selected from at least one of methyltetrahydrophthalic anhydride, liquid methylhexahydrophthalic anhydride, and liquid methylnadic anhydride.

[0022] The amount of the anhydride curing agent added can be measured according to the calculation formula commonly used in the industry. For example, it can be calculated according to the following formula:

[0023] The dosage of anhydride curing agent is usually calculated according to the following formula:

[0024] W=A E ×E×K

[0025] Where: W---the mass of anhydride curing agent required for every 100g of epoxy resin, g;

[0026] AE---anhydride molar mass, g / mol;

[0027] E---Epoxy value of epoxy resin;

[0028] K---the amount of anhydride required per molar mass of epoxy group, mol. Empirical data, it varies in the range of 0.5 to 1.1, and is generally taken as 0.85.

[0029] The amine curing agent is preferably diethyltoluenediamine and / or menthanediamine.

[0030] The amount of the amine curing agent added can be measured according to a stoichiometric ratio.

[0031] The calculation method of the amount of amine curing agent is based on the interaction between an active hydrogen on the amine group and an epoxy group. The amount of various primary amines and secondary amines can be calculated as follows:

[0032]

[0033] Where: W---the mass of amine curing agent required for every 100g of epoxy resin, g;

[0034] M---Molecular weight of amine curing agent;

[0035] Hn --- the number of active hydrogen atoms on the amine group in a curing agent molecule;

[0036] E---Epoxy value of epoxy resin.

[0037] The accelerator may be selected from at least one of triethanolamine, tris(dimethylaminopropyl)amine, 2,4,6-tris(dimethylaminomethyl)phenol, 2-ethyl-4-methylimidazole, and 2-methylimidazole; preferably at least one of 2-ethyl-4-methylimidazole and 2-methylimidazole;

[0038] The amount of the accelerator is preferably 3-10wt% of the total weight of the epoxy resin and the diluent, more preferably 5-8wt%. (such as 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt% or any value between the above values ​​or a numerical range between any two of the above values)

[0039] The present invention may further comprise a defoamer, which may be selected from one or more of a fat defoamer, a polyether defoamer, a silicone defoamer, a polyether-modified silicone defoamer, and a fluorine-modified silicone defoamer; preferably a polyether defoamer;

[0040] The amount of the defoamer is preferably 0.3-1.2 wt% of the weight of the epoxy resin, more preferably 0.5-1.0 wt% (such as 0.5 wt%, 0.8 wt%, 1.0 wt% or any value between the above values ​​or a numerical range between any two of the above values) and can be adjusted according to actual conditions.

[0041] The curing temperature of the epoxy resin composition is not higher than the softening temperature of the polyethylene liner; specifically, the curing temperature of the epoxy resin composition is not higher than 110°C.

[0042] The second object of the present invention is to provide a method for preparing the epoxy resin composition for the winding layer of the IV type hydrogen storage bottle, which may include the following steps:

[0043] Step 1, preparing component A: stirring the liquid epoxy resin, adding a diluent, optionally adding a defoaming agent, stirring at high speed, then stopping stirring, and standing for use;

[0044] The rotation speed of the high-speed stirring is preferably 2000-3000 r / min;

[0045] The high-speed stirring time is preferably 10 to 15 minutes.

[0046] Step 2, preparing component B: mixing the curing agent and the accelerator, heating and stirring, cooling and setting aside; the heating is preferably heated to 60-145° C.; the stirring is preferably stirred at 300-1000 r / min for 10-20 min;

[0047] Step 3: Pour component B into component A and stir; the stirring is performed at a speed not exceeding 300 to 1000 r / min for 10 to 20 minutes.

[0048] More specifically, the preparation method may include the following steps:

[0049] Step 1, prepare component A: pour liquid epoxy resin into a container and stir it mechanically at a slow speed, weigh the diluent and pour it into the container, then weigh the defoamer and pour it into the container, stir at a high speed of 2000-3000r / min for 10-15 minutes, then stop stirring and let it stand for use.

[0050] Step 2, prepare component B: weigh the curing agent and pour it into a container equipped with a condenser, then weigh the accelerator and pour it into the above container, heat to 60-145°C, stir at 300r / min for 10min, then stop, cool and set aside.

[0051] Step 3: Slowly pour component B into component A, stir at a speed not exceeding 300r / min for 10 minutes, and then pour into the glue tank for use.

[0052] The third object of the present invention is to provide the application of the epoxy resin composition for the winding layer of Type IV hydrogen storage bottle described in the first object of the present invention or the epoxy resin composition prepared by the preparation method described in the second object of the present invention, preferably in hydrogen storage bottles.

[0053] The beneficial effects of the present invention are: the system has low viscosity, slow reaction at room temperature, and can meet the requirements of the winding process for the application period. The curing temperature required for the epoxy resin system is not higher than the softening temperature of the polyethylene liner. The glass transition temperature of the cured product of the epoxy resin system is higher than the requirements of various standards (such as the U.S. Department of Transportation DOTCFFC 2007). The impact strength of the cured product of the epoxy resin system cast body is also significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 1 and 2 are non-isothermal DSC scanning curves of the epoxy resin compositions of Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0055] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the content of the present invention still fall within the scope of protection of the present invention.

[0056] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0057] Source of raw materials

[0058] The raw materials used in the examples and comparative examples, unless otherwise specified, are disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0059] Example 1

[0060] Weigh each component by weight: 100 parts of E54 epoxy resin, 5 parts of 1,4-butanediol diglycidyl ether, 85 parts of methyl tetrahydrophthalic anhydride, 5 parts of 2-ethyl-4-methylimidazole, and 0.5 parts of polyether defoamer BYK054. Pour the above components into a three-necked flask, stir at 30°C, and vacuum degas for 5 minutes at 60KPa. Pour the mixture into a mold and cure at 80°C for 1 hour and 100°C for 4 hours.

[0061] Example 2

[0062] Weigh each component by weight: 100 parts of liquid bisphenol F epoxy resin (F-170), 5 parts of 1,4-butanediol diglycidyl ether, 95 parts of methyl tetrahydrophthalic anhydride, 5 parts of 2-ethyl-4-methylimidazole, and 0.5 parts of polyether defoamer BYK054. Pour the above components into a three-necked flask, stir at 30°C, and vacuum degas for 5 minutes at 60KPa. Pour the mixture into a mold and cure at 80°C for 1 hour and 100°C for 4 hours.

[0063] Example 3

[0064] Weigh each component by weight: 50 parts of E54 epoxy resin, 50 parts of liquid bisphenol F epoxy resin (F-170), 5 parts of 1,4-butanediol diglycidyl ether, 90 parts of methyl tetrahydrophthalic anhydride, 5 parts of 2-ethyl-4-methylimidazole, and 0.5 parts of BYK054 polyether defoamer. Pour the above components into a three-necked flask, stir at 30°C, and vacuum degas for 5 minutes at 60KPa. Pour the mixture into a mold and cure at 80°C for 1 hour and 100°C for 4 hours.

[0065] Example 4

[0066] The 5 parts of 1,4-butanediol diglycidyl ether in Example 1 were replaced with 10 parts of 1,4-butanediol diglycidyl ether, and the rest remained unchanged.

[0067] Example 5

[0068] Weigh each component by weight: 50 parts of E54 epoxy resin, 50 parts of liquid bisphenol F epoxy resin (F-170), 5 parts of 1,4-butanediol diglycidyl ether, 95 parts of methyl nadic anhydride, 5 parts of 2-ethyl-4-methylimidazole, and 0.5 parts of polyether defoamer BYK054. Pour the above components into a three-necked flask, stir at 30°C, and vacuum degas for 5 minutes at 60KPa. Pour the mixture into a mold and cure at 80°C for 1 hour and 100°C for 4 hours.

[0069] Example 6

[0070] The 5 parts of 2-ethyl-4-methylimidazole in Example 1 were replaced with 8 parts of 2-ethyl-4-methylimidazole, and the rest remained unchanged.

[0071] Example 7

[0072] Weigh each component by weight: 50 parts of E54 epoxy resin, 50 parts of liquid bisphenol F epoxy resin (F-170), 5 parts of 1,4-butanediol diglycidyl ether, 90 parts of methyltetrahydrophthalic anhydride, 5 parts of 2-methylimidazole, and 0.5 parts of polyether defoamer. First, pour methyltetrahydrophthalic anhydride and 2-methylimidazole into a three-necked flask equipped with a condenser, heat to 145℃ and stir for 10 minutes, cool to 30℃, add the remaining components into the three-necked flask, and vacuum degas at 60KPa for 5 minutes, pour the mixture into the mold, and cure at 80℃ for 1h and 100℃ for 4h.

[0073] Example 8

[0074] The 85 parts of methyltetrahydrophthalic anhydride in Example 1 were replaced by 27 parts of diethyltoluenediamine, and the rest remained unchanged.

[0075] Example 9

[0076] The 5 parts of 2-ethyl-4-methylimidazole in Example 1 were replaced with 10 parts of 2-ethyl-4-methylimidazole, and the rest remained unchanged.

[0077] Comparative Example 1

[0078] The 5 parts of 2-ethyl-4-methylimidazole in Example 1 were replaced with 1 part of 2-ethyl-4-methylimidazole, and the rest remained unchanged.

[0079] Comparative Example 2

[0080] The 5 parts of 2-ethyl-4-methylimidazole in Example 1 were replaced with 5 parts of 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30), and the rest remained unchanged.

[0081] The products obtained in Examples 1 to 9 and Comparative Examples 1 to 2 were subjected to performance testing, and the results are shown in Table 1 below.

[0082] Table 1

[0083]

[0084]

[0085] From the attached Figure 1 It can be seen that after increasing the amount of imidazole accelerator in Example 1 of the present application, the curing temperature of the system is greatly reduced, so that curing can be performed at a temperature lower than the softening temperature of the polyethylene liner.

[0086] As can be seen from Table 1 above, the epoxy resin composition for the winding layer of the IV type hydrogen storage bottle described in the present application changes the amount of the accelerator so that the curing temperature required by the epoxy resin / anhydride system is lower than the softening temperature of the polyethylene liner, and the glass transition temperature of the cured product after curing is higher than the standard requirement, while improving the impact performance. The system has a low viscosity, which is conducive to the resin infiltration of the fiber, and reacts slowly at room temperature, which can meet the requirements of the winding process for the applicable period.

Claims

1. An epoxy resin composition for a winding layer of a type IV hydrogen storage bottle, comprising the following components: epoxy resin, diluent, curing agent, and accelerator; The epoxy resin is a liquid epoxy resin.

2. The epoxy resin composition for the winding layer of a type IV hydrogen storage bottle according to claim 1, characterized in that: The epoxy resin is selected from at least one of liquid bisphenol A epoxy resin, liquid hydrogenated bisphenol A epoxy resin, liquid bisphenol F epoxy resin, liquid glycidyl ester epoxy resin, and liquid glycidyl amine epoxy resin; preferably at least one of liquid bisphenol A epoxy resin and liquid bisphenol F epoxy resin.

3. The epoxy resin composition for the winding layer of a type IV hydrogen storage bottle according to claim 1, characterized in that: The diluent is selected from at least one of an inactive diluent and an active diluent; The inactive diluent does not contain an epoxy group, and is preferably at least one selected from acetone, ethanol, toluene, xylene, ethyl acetate, dibutyl phthalate, dioctyl phthalate, styrene, diallyl phthalate, and benzyl alcohol; and / or, The active diluent contains a low-viscosity substance with at least one epoxy group; the active diluent is selected from at least one of polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, butyl glycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, furanmethyl glycidyl ether, ethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, o-cresyl glycidyl ether, benzyl glycidyl ether, resorcinol diglycidyl ether, octyl glycidyl ether, carbon 12-14 alkyl glycidyl ether (AGE), tert-butyl glycidyl carbonate, neodecanoic acid glycidyl ether, and methacrylate glycidyl ether; The diluent is preferably at least one of benzyl alcohol (BA), 1,4-butanediol diglycidyl ether (622), and carbon 12-14 alkyl glycidyl ether (AGE).

4. The epoxy resin composition for the winding layer of a type IV hydrogen storage bottle according to claim 1, characterized in that: The amount of the diluent is preferably 3-15 wt %, more preferably 5-10 wt %, based on the weight of the epoxy resin.

5. The epoxy resin composition for the winding layer of a type IV hydrogen storage bottle according to claim 1, characterized in that: The curing agent is selected from an anhydride curing agent or an amine curing agent; The acid anhydride curing agent is preferably at least one selected from methyltetrahydrophthalic anhydride, liquid methylhexahydrophthalic anhydride, and liquid methylnadic anhydride; and / or, The amine curing agent is preferably selected from diethyltoluenediamine and / or menthanediamine.

6. The epoxy resin composition for the winding layer of a type IV hydrogen storage bottle according to claim 1, characterized in that: The accelerator is selected from at least one of triethanolamine, tris(dimethylaminopropyl)amine, 2,4,6-tris(dimethylaminomethyl)phenol, 2-ethyl-4-methylimidazole, and 2-methylimidazole; preferably at least one of 2-ethyl-4-methylimidazole and 2-methylimidazole.

7. The epoxy resin composition for the winding layer of a type IV hydrogen storage bottle according to claim 1, characterized in that: The amount of the accelerator used is 3-10 wt % of the total weight of the epoxy resin and the diluent, and more preferably 5-8 wt %.

8. The epoxy resin composition for the winding layer of a type IV hydrogen storage bottle according to claim 1, characterized in that It also contains a defoaming agent; The defoamer is selected from one or more of a fat defoamer, a polyether defoamer, a silicone defoamer, a polyether-modified silicone defoamer, and a fluorine-modified silicone defoamer; preferably a polyether defoamer; The amount of the defoamer is preferably 0.3-1.2 wt % of the weight of the epoxy resin, more preferably 0.5-1.0 wt %.

9. The method for preparing the epoxy resin composition for the winding layer of the IV type hydrogen storage bottle according to any one of claims 1 to 8, characterized in that The following steps are involved: Step 1, preparing component A: stirring the epoxy resin, adding a diluent, optionally adding a defoaming agent, stirring and stopping stirring, and standing for use; Step 2, preparing component B: mixing the curing agent and the accelerator, heating and stirring, cooling and setting aside; the heating is preferably heated to 60-145°C; Step 3: Pour component B into component A and stir.

10. Use of the epoxy resin composition for the winding layer of a type IV hydrogen storage bottle according to any one of claims 1 to 8 or the epoxy resin composition prepared by the preparation method according to claim 9.

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