Hot melt adhesive membrane for bonding proton exchange membrane of hydrogen energy battery and preparation method of hot melt adhesive membrane

Abstract

The invention relates to the technical field of hot melt adhesive membranes, and discloses a hot melt adhesive membrane for bonding a proton exchange membrane of a hydrogen energy battery and a preparation method of the hot melt adhesive membrane. A tackifying resin; the antioxidant is formed by compounding a hindered phenol type antioxidant and a phosphite ester type antioxidant; a lubricant; the composite modified polyamide resin is adopted as thermoplastic resin, and the limitation of a traditional material is broken through. Although polyamide 6 has certain mechanical properties and chemical stability, the polyamide 6 still has defects under the complex working conditions of hydrogen energy batteries. Through graft copolymerization with a tackifying monomer maleic anhydride, a polar group is successfully introduced, so that the adhesive ability to a proton exchange membrane is greatly improved, which is difficult to reach by many existing adhesive materials. Meanwhile, the modified nano silicon dioxide is innovatively added and is tightly combined with a polyamide molecular chain by utilizing the high specific surface area and the small-size effect of the modified nano silicon dioxide, so that a stable network structure is formed.

Description

Technical Field

[0001] The invention relates to the technical field of hot melt adhesive films, in particular to a hot melt adhesive film for bonding a proton exchange membrane of a hydrogen energy battery and a preparation method thereof. Background Art

[0002] In the development process of hydrogen energy batteries, the proton exchange membrane is a core component, and its reliable connection with other components such as electrodes and bipolar plates is the key to ensuring the efficient and stable operation of the battery. When hydrogen energy batteries are working, complex physical and chemical changes will occur inside, accompanied by temperature fluctuations, chemical corrosion and mechanical stress, which requires the materials used to bond the proton exchange membrane to have extremely high comprehensive performance.

[0003] However, the traditional adhesive materials commonly found on the market currently have obvious defects in many aspects. In terms of bonding strength, many common hot melt adhesives have limited bonding layer strength after curing. Under the actual operating conditions of hydrogen energy batteries, especially during the charging and discharging process of the battery, the volume changes caused by internal chemical reactions and the effects of thermal expansion and contraction will cause continuous stress on the bonding parts. Traditional hot melt adhesives are unable to withstand this long-term and complex stress, resulting in a gradual decrease in bonding strength, which in turn causes loosening and separation between components, seriously affecting the overall performance and service life of the battery.

[0004] In terms of high temperature resistance, when hydrogen energy batteries are in high load working state, the internal temperature of the battery will rise rapidly. Under high temperature environment, the activity of the molecular chain of ordinary hot melt adhesive is enhanced, and the softening point is reduced, resulting in a significant decrease in its mechanical properties. This will not only weaken the bonding strength, but also cause the hot melt adhesive to flow and deform, destroying the structural stability of the battery and hindering the normal operation of the battery.

[0005] In summary, existing adhesive materials are unable to meet the increasingly stringent performance requirements of hydrogen energy batteries in terms of bonding strength, high temperature resistance and other properties.

[0006] Based on this, we proposed a hot melt adhesive film for bonding proton exchange membranes of hydrogen energy batteries. Summary of the invention

[0007] 1. Technical issues to be resolved

[0008] In view of the deficiencies in the prior art, the present invention provides a hot melt adhesive film for bonding a proton exchange membrane of a hydrogen energy battery and a preparation method thereof.

[0009] (II) Technical solution

[0010] To achieve the above-mentioned purpose, the present invention provides the following technical solutions:

[0011] A hot-melt adhesive film for bonding the proton exchange membrane of a hydrogen energy battery, comprising the following components in parts by weight:

[0012] Thermoplastic resin: 70 parts - 80 parts, and the thermoplastic resin is a composite modified polyamide resin;

[0013] Tackifying resin: 12 parts - 18 parts, and the tackifying resin is one or more of terpene resin, rosin resin, and petroleum resin;

[0014] Antioxidant: 1 part - 1.2 parts, and the antioxidant is composed of a hindered phenol antioxidant and a phosphite antioxidant;

[0015] Among them, the mixing mass ratio of the hindered phenol antioxidant and the phosphite antioxidant is 1:2;

[0016] Flame retardant: 3 parts - 4 parts;

[0017] Lubricant: 1.2 parts - 1.6 parts.

[0018] As a further technical solution, the composite modified polyamide resin is prepared through raw material preparation and graft copolymerization reaction steps.

[0019] As a further technical solution, the raw material preparation step is: taking 80 - 90 g of polyamide 6 resin, 12 - 15 g of tackifying monomer, 0.3 - 0.4 g of catalyst, and 5 - 6 g of modified nano-silica;

[0020] Among them, the tackifying monomer is selected as maleic anhydride;

[0021] The catalyst is selected as dibutyltin dilaurate.

[0022] As a further technical solution, the preparation method of the modified nano-silica is: taking 5 - 6 g of nano-silica powder and adding it to 200 - 220 mL of toluene solution, ultrasonically dispersing it at 50 kHz for 20 min to form a uniform nano-silica dispersion liquid, adding 3 - 5 g of silane coupling agent KH-550 to the nano-silica dispersion liquid, refluxing and stirring at 70 - 75 °C for 4 h, after the reaction ends, through suction filtration, washing the precipitate with anhydrous ethanol 3 times, and finally drying it in a vacuum drying oven at 80 °C for 6 h to obtain the modified nano-silica.

[0023] As a further technical solution, the graft copolymerization reaction step is: adding polyamide 6 resin, tackifying monomer maleic anhydride, and catalyst dibutyltin dilaurate to the reaction kettle in sequence according to the weight of each component, introducing nitrogen into the reaction kettle to discharge the air in the reaction kettle, under nitrogen protection, heating to 195 °C, and stirring and reacting at a speed of 250 r / min for 30 min, then adding the modified nano-silica, continuing to stir and react for 2 h, discharging, washing with water, and drying.

[0024] As a further technical solution: the thickness of the hot melt adhesive film is 50-60 μm.

[0025] As a further technical solution, the flame retardant is any one of aluminum hydroxide and magnesium hydroxide.

[0026] As a further technical solution, the lubricant is compounded by stearic acid and zinc stearate, wherein the mixing mass ratio of stearic acid and zinc stearate is 1:1.

[0027] A preparation method of a hot melt adhesive for bonding a proton exchange membrane of a hydrogen energy battery includes the following steps:

[0028] Prepare thermoplastic resin, tackifying resin, antioxidant and other additives according to the described mass percentages;

[0029] Add the above raw materials into a high-speed mixer and mix for 40 min under the conditions of 80 °C and 800 r / min to obtain a mixed material;

[0030] Put the above mixed material into a twin-screw extruder for melt extrusion, the extrusion temperature is 205-210 °C, and the screw speed is 80 r / min;

[0031] The extruded material is cast onto a cooling roll through a die head and cooled and formed to obtain the hot melt adhesive, and the temperature of the cooling roll is 25 °C.

[0032] (III) Beneficial effects

[0033] Compared with the prior art, the present invention provides a hot melt adhesive film for bonding a proton exchange membrane of a hydrogen energy battery, which has the following beneficial effects:

[0034] The present invention uses a composite modified polyamide resin as the thermoplastic resin, breaking through the limitations of traditional materials. Although polyamide 6 itself has certain mechanical properties and chemical stability, it is still insufficient in the face of the complex working conditions of hydrogen energy batteries. By graft copolymerization with the tackifying monomer maleic anhydride, polar groups are successfully introduced, greatly improving the bonding ability to the proton exchange membrane, which is difficult to achieve by many existing bonding materials. At the same time, modified nano-silica is innovatively added. Utilizing its high specific surface area and small size effect, it closely combines with the polyamide molecular chain to form a stable network structure. This not only enhances the tensile strength of the hot melt adhesive film, making it not easy to break under external force, but also significantly improves the heat resistance performance, and still can maintain good mechanical properties in a high-temperature environment, effectively solving the problem that the performance of existing materials drops sharply at high temperatures.

[0035] The addition of tackifying resins such as terpene resin, rosin resin, and petroleum resin brings excellent tack control ability to the hot melt adhesive film. Terpene resin, with its good tackifying effect and weather resistance, ensures the long-term tack of the hot melt adhesive film in different environments; rosin resin rapidly improves the initial tack, making the bonding process more efficient; petroleum resin comprehensively improves the overall bonding performance. By using these tackifying resins alone or in a clever combination, the tack and bonding characteristics of the hot melt adhesive film can be precisely adjusted according to the different working conditions and application scenarios of hydrogen energy batteries, while such flexible and precise performance adjustment is often difficult to achieve in the prior art.

[0036] The efficient synergy of antioxidants, with hindered phenol antioxidants and phosphite antioxidants compounded in a scientific ratio of 1:2, exerts a powerful synergistic antioxidant effect. Hindered phenol antioxidants can rapidly capture free radicals and effectively interrupt the oxidation chain reaction, while phosphite antioxidants timely decompose hydroperoxides to prevent the oxidation process from the source. The two complement each other, effectively preventing the oxidation and aging of the hot melt adhesive film during use and storage, greatly extending the service life, and ensuring long-term performance stability, which is a long-term stable performance that many existing bonding materials cannot achieve.

[0037] The addition of flame retardants such as aluminum hydroxide and magnesium hydroxide endows the hot melt adhesive film with excellent flame retardant properties. In a high-temperature environment, the flame retardant rapidly decomposes and absorbs heat, reducing the surrounding temperature. At the same time, a dense heat insulation layer is formed to effectively prevent the spread of fire, providing a reliable guarantee for the safe operation of hydrogen energy batteries, while existing materials often have difficulty achieving such a high level of fire protection performance. The lubricant compounded by stearic acid and zinc stearate significantly reduces the internal and external friction of the hot melt adhesive film during the processing process, making the extrusion and casting processes smoother, greatly improving the production efficiency and product quality stability, which is also an advantage that the prior art is difficult to compare in terms of processing performance.

[0038] In summary, through the careful screening, modification, and scientific ratio of each raw material component, the hot melt adhesive film of the present invention has excellent bonding strength, high-temperature resistance, antioxidant performance, and flame retardant performance, comprehensively surpassing the prior art, and can perfectly meet the stringent requirements of hydrogen energy batteries for bonding materials, providing strong support for the development of hydrogen energy battery technology. Detailed Embodiments

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0040] Example 1

[0041] Raw material preparation:

[0042] Thermoplastic resin: Take 70 g of composite modified polyamide resin;

[0043] Among them, the composite modified polyamide resin is prepared by the following method: Prepare 80 g of polyamide 6 resin, 12 g of tackifying monomer maleic anhydride, 0.3 g of catalyst dibutyltin dilaurate, and 5 g of modified nano-silica. First, add 5 g of nano-silica powder into 200 mL of toluene solution, ultrasonically disperse it at 50 kHz for 20 min, then add 3 g of silane coupling agent KH-550, and reflux and stir for reaction at 70 °C for 4 h. Filter by suction, wash the precipitate with absolute ethanol 3 times, and dry it in a vacuum drying oven at 80 °C for 6 h to obtain modified nano-silica. Then, add polyamide 6 resin, maleic anhydride, and dibutyltin dilaurate into the reaction kettle in sequence, introduce nitrogen to exhaust air, heat up to 178 °C under nitrogen protection, stir and react at a speed of 250 r / min for 30 min, add modified nano-silica and continue to stir and react for 2 h, discharge, wash with water, and dry to obtain composite modified polyamide resin.

[0044] Tackifying resin: Select 18 g of terpene resin.

[0045] Antioxidant: 0.4 g of hindered phenol antioxidant and 0.8 g of phosphite antioxidant are compounded (mass ratio 1:2).

[0046] 0.3 g of aluminum hydroxide flame retardant, 1.2 g of lubricant.

[0047] Preparation process: Add the above raw materials into a high-speed mixer, mix at 80 °C and 800 r / min for 40 min to obtain a mixed material. Put the mixed material into a twin-screw extruder for melt extrusion, the extrusion temperature is 205 °C, and the screw speed is 80 r / min. The extruded material is cast onto a cooling roll at 25 °C through a die head for cooling and forming to obtain a hot melt adhesive film with a thickness of 50 μm.

[0048] Example 2

[0049] Raw material preparation:

[0050] Thermoplastic resin: Take 75 g of composite modified polyamide resin;

[0051] When preparing the composite modified polyamide resin, 85 g of polyamide 6 resin, 13 g of tackifying monomer maleic anhydride, 0.35 g of catalyst dibutyltin dilaurate, and 5.5 g of modified nano-silica are used. The preparation of modified nano-silica is to add 5.5 g of nano-silica powder into 210 mL of toluene solution for ultrasonic dispersion, add 4 g of silane coupling agent KH-550 for reaction, and the subsequent treatment is the same as that in Example 1; the preparation steps of the composite modified polyamide resin are also the same as those in Example 1.

[0052] Tackifying resin: select 15 g of rosin resin.

[0053] Antioxidant: 0.4 g of hindered phenol antioxidant and 0.8 g of phosphite antioxidant are compounded.

[0054] 0.4 g of magnesium hydroxide flame retardant and 1.5 g of lubricant.

[0055] Preparation process: The mixing, extrusion and molding steps are the same as those in Example 1, and finally a hot melt adhesive film with a thickness of 55 μm is obtained.

[0056] Example 3

[0057] Raw material preparation:

[0058] Thermoplastic resin: Take 80 g of composite modified polyamide resin;

[0059] The composite modified polyamide resin is prepared from 90 g of polyamide 6 resin, 15 g of tackifying monomer maleic anhydride, 0.4 g of catalyst dibutyltin dilaurate and 6 g of modified nano-silica. The preparation of modified nano-silica is to add 6 g of nano-silica powder into 220 mL of toluene solution for ultrasonic dispersion, add 5 g of silane coupling agent KH-550 for reaction, and the subsequent treatment is the same as that in Example 1. The preparation steps of the composite modified polyamide resin are also the same as those in Example 1.

[0060] Tackifying resin: select 12 g of petroleum resin.

[0061] Antioxidant: 0.4 g of hindered phenol antioxidant and 0.8 g of phosphite antioxidant are compounded.

[0062] 0.5 g of aluminum hydroxide flame retardant and 1.5 g of lubricant.

[0063] Preparation process: The same as that in Example 1, and finally a hot melt adhesive film with a thickness of 60 μm is obtained.

[0064] Example 4

[0065] Raw material preparation:

[0066] Thermoplastic resin: Take 72 g of composite modified polyamide resin;

[0067] Among them, the composite modified polyamide resin is prepared from 82 g of polyamide 6 resin, 14 g of tackifying monomer maleic anhydride, 0.32 g of catalyst dibutyltin dilaurate and 5.2 g of modified nano-silica. The preparation of modified nano-silica is to add 5.2 g of nano-silica powder into 205 mL of toluene solution for ultrasonic dispersion, add 3.5 g of silane coupling agent KH-550 for reaction, and the subsequent treatment is the same as that in Example 1. The preparation steps of the composite modified polyamide resin are also the same as those in Example 1.

[0068] Tackifying resin: A blend of terpene resin and rosin resin, 9 g each, is selected.

[0069] Antioxidant: A combination of 0.4 g of a hindered phenol antioxidant and 0.8 g of a phosphite antioxidant.

[0070] 0.35 g of magnesium hydroxide flame retardant; 1.6 g of lubricant.

[0071] Preparation process: Using the same mixing, extrusion, and molding processes, a hot melt adhesive film with a thickness of 52 μm is obtained.

[0072] The following are comparative examples:

[0073] Comparative Example 1:

[0074] Based on Example 1, the composite modified polyamide resin is replaced with unmodified polyamide 6 resin, and the other technical solutions are the same as those in Example 1.

[0075] Comparative Example 2:

[0076] Based on Example 1, during the preparation of the composite modified polyamide resin, modified nano-silica is not added, and the other technical solutions are the same as those in Example 1.

[0077] Test:

[0078] Adhesive strength test: Test the adhesive strength of the hot melt adhesive film of the present invention to the proton exchange membrane of the hydrogen energy battery;

[0079] Test method: Prepare multiple groups of proton exchange membranes of the hydrogen energy battery and other components to be bonded with the same specifications. Conduct equivalent tests on the hot melt adhesive films of the examples and comparative examples of the present invention. According to the tensile test method of the industry standard, stretch the bonded components on a universal material testing machine, record the maximum tensile force at the time of failure, calculate the adhesive strength, and repeat each test 10 times and take the average value;

[0080] Test results:

[0081] Table 1

[0082] Bond strength MPa Example 1 12.86 Example 2 12.70 Example 3 12.51 Example 4 12.93 Comparative Example 1 6.33 Comparative Example 2 8.27

[0083] As can be seen from Table 1, the hot melt adhesive film of the present invention has a significant improvement in adhesive performance.

[0084] High temperature resistance performance test test method: Divide the bonded proton exchange membrane components into 6 groups, and use the hot melt adhesive films of the examples and comparative examples respectively. Place each group of components in a high temperature test chamber, set the temperature to 80 °C, keep for 500 hours and then take out, observe the bonding situation of the components, and at the same time test their adhesive strength again. Repeat each test 8 times and take the average value;

[0085] Bond strength reduction rate = (Initial bond strength - Bond strength after test) / Initial bond strength × 100%;

[0086] Table 2

[0087]

[0088]

[0089] As can be seen from Table 2, the hot melt adhesive film of the present invention has good high temperature resistance.

[0090] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A hot melt adhesive film for bonding proton exchange membranes of hydrogen energy batteries, characterized in that: The composition comprises the following components in parts by weight: Thermoplastic resin: 70-80 parts, the thermoplastic resin is a composite modified polyamide resin; Tackifying resin: 12-18 parts, the tackifying resin is one or more of terpene resin, rosin resin, and petroleum resin; Antioxidant: 1-1.2 parts, the antioxidant is a compound of hindered phenol antioxidant and phosphite antioxidant; Among them, the mixed mass ratio of hindered phenol antioxidant and phosphite antioxidant is 1:2; Flame retardant: 3-4 parts; Lubricant: 1.2 parts - 1.6 parts.

2. The hot melt adhesive film for bonding the proton exchange membrane of hydrogen energy battery according to claim 1, characterized in that: The composite modified polyamide resin is prepared through raw material preparation and graft copolymerization reaction steps.

3. The hot melt adhesive film for bonding the proton exchange membrane of hydrogen energy battery according to claim 2, characterized in that: The raw material preparation steps are as follows: 80-90 g of polyamide 6 resin, 12-15 g of viscosity-increasing monomer, 0.3-0.4 g of catalyst, and 5-6 g of modified nano-silicon dioxide; Among them, maleic anhydride is selected as the viscosity-increasing monomer; The catalyst is dibutyltin dilaurate.

4. The hot melt adhesive film for bonding the proton exchange membrane of hydrogen energy battery according to claim 2, characterized in that: The modified nano-silicon dioxide preparation method comprises the following steps: adding 5-6 g of nano-silicon dioxide powder to 200-220 mL of toluene solution, ultrasonically dispersing the solution at 50 kHz for 20 minutes to form a uniform nano-silicon dioxide dispersion, adding 3-5 g of silane coupling agent KH-550 to the nano-silicon dioxide dispersion, refluxing and stirring the solution at 70-75° C. for 4 hours, filtering the solution after the reaction is completed, washing the solution with anhydrous ethanol for 3 times, and finally drying the solution in a vacuum drying oven at 80° C. for 6 hours to obtain the modified nano-silicon dioxide.

5. The hot melt adhesive film for bonding the proton exchange membrane of hydrogen energy battery according to claim 2, characterized in that: The graft copolymerization reaction steps are: polyamide 6 resin, viscosity-increasing monomer maleic anhydride, and catalyst dibutyltin dilaurate are added to the reactor in sequence according to the weight of each component, nitrogen is introduced into the reactor to exhaust the air in the reactor, the temperature is raised to 195° C. under nitrogen protection, and the reaction is stirred at a speed of 250 r / min for 30 minutes, then modified nano-silica is added, the reaction is continued with stirring for 2 hours, the material is discharged, washed with water, and dried.

6. The hot melt adhesive film for bonding the proton exchange membrane of hydrogen energy battery according to claim 1, characterized in that: The thickness of the hot melt adhesive film is 50-60 μm.

7. The hot melt adhesive film for bonding the proton exchange membrane of hydrogen energy battery according to claim 1, characterized in that: The flame retardant is any one of aluminum hydroxide and magnesium hydroxide.

8. The hot melt adhesive film for bonding proton exchange membrane of hydrogen energy battery according to claim 1, characterized in that: The lubricant is a compound of stearic acid and zinc stearate, wherein the mass ratio of stearic acid to zinc stearate is 1:

1.

9. A method for preparing a hot melt adhesive for bonding a proton exchange membrane of a hydrogen energy battery, characterized in that: The following steps are involved: According to the mass percentage of claim 1, a thermoplastic resin, a tackifying resin, an antioxidant and other additives are prepared; The above raw materials were added into a high-speed mixer, and mixed for 40 minutes at 80°C and 800 r / min to obtain a mixed material; The mixed material is put into a twin-screw extruder for melt extrusion at a temperature of 205-210°C and a screw speed of 80r / min; The extruded material is cast onto a cooling roller through a die head, and cooled and formed to obtain the hot melt adhesive, and the temperature of the cooling roller is 25°C.

Images