A bio-based modified high self-healing bipolar plate gas channel seal adhesive

Abstract

The application belongs to the technical field of high polymer materials, and particularly relates to a kind of bio-based modified high self-repairing bipolar plate gas path seal adhesive, and preparation raw materials include the following components calculated by mass fraction: polymer polyol 20-55 parts; bio-based polyol 20-53 parts; diisocyanate 30-60 parts; catalyst 0.1-0.5 parts; chain extender 5-12 parts; neutralizing agent 3-5 parts; acrylic monomer 5-15 parts; metal ion 1-2 parts; deionized water 100-202 parts; coupling agent 5-6 parts; photoinitiator 2-5 parts.The adhesive of the application selects bio-based modified waterborne polyurethane as raw material, has strong mechanical properties, and at the same time has good air tightness, high temperature resistance, elasticity, self-repairing, and is applied to the sealing and bonding of bipolar plate gas path.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer materials, and particularly relates to a bio-based modified high self-repairing bipolar plate gas path sealing adhesive. BACKGROUND

[0002] Waterborne polyurethane (WPU) is a binary adhesive system with water instead of organic polymer as the dispersion system, which is now often applied in manufacturing, textile and other industries. However, the material will be broken in the micro interface during processing or use, which greatly reduces the mechanical properties and also reduces the service life. Therefore, endowing waterborne polyurethane with high self-repairing function is the research direction of domestic and foreign researchers. At the same time, only the performance of waterborne polyurethane itself cannot meet the required index of today's technology. Due to the existence of hydrophilic groups, the water resistance, thermal stability and solvent resistance are poor, which has greatly restricted the actual application field of waterborne polyurethane. In order to improve these problems, domestic and foreign scholars have developed various methods for modifying waterborne polyurethane, such as bio-based modified waterborne polyurethane (EWPU). Bio-based modification refers to the modification of waterborne polyurethane by using natural renewable resource-based vegetable oil polyol. In the face of the lack of fossil energy, low-cost, degradable and renewable biomass resources and waterborne polyurethane with excellent performance have become the current research hotspot. Compared with ordinary polyols, EWPU has the characteristics of low cost, easy availability, low pollution and energy saving, which can promote its application in more fields. In addition, the current ultraviolet (UV) curing technology is mature. By adding a photoinitiator (photosensitizer) to the prepared adhesive, low-temperature curing, high-speed curing, saving preparation time and improving production efficiency can be realized. Compared with the traditional high-temperature curing method, the volatilization of substances can be reduced, energy can be saved, and environmental protection can be realized. At the same time, the high self-repairing performance researched is also the object of the increasingly ambitious hydrogen energy automobile industry. It can consolidate the bipolar plate part of the fuel cell and prolong the service life of the bipolar plate. As the core of the fuel cell, the bipolar plate is responsible for transporting gas, collecting electrons and effectively removing product water. It needs an adhesive with excellent air tightness to improve the sealing property of the bipolar plate, prevent the mutual interpenetration of reaction gas and cooling liquid, strictly separate gas and liquid, and present a bipolar plate with higher quality. SUMMARY

[0003] The existing bipolar plate gas path sealing adhesive cannot simultaneously have good air tightness, high temperature resistance, elasticity, self-healing property and short service life, and the present application provides a bio-based modified high self-repairing bipolar plate gas path sealing adhesive.

[0004] The present application solves the above problems by the following technical solutions:

[0005] A kind of bipolar plate gas path seal adhesive of bio-based modified high self-repairing, preparation raw material includes the following component by mass fraction calculation:

[0006] Polymer polyol 20-55 parts;

[0007] Bio-based polyol 20-53 parts;

[0008] Diisocyanate 30-60 parts;

[0009] Catalyst 0.1-0.5 parts;

[0010] Chain extender 5-12 parts;

[0011] Neutralizing agent 3-5 parts;

[0012] Acrylic monomer 5-15 parts;

[0013] Metal ion 1-2 parts;

[0014] Deionized water 100-202 parts;

[0015] Coupling agent 5-6 parts;

[0016] Photoinitiator 2-5 parts.

[0017] Further, the polymer polyol is one or both of polyether polyol or polycarbonate polyol.

[0018] Further, the bio-based polyol is one of alcoholysis flax oil polyol, castor oil, palm oil-based polyol, acetate corn starch polyol.

[0019] Further, the diisocyanate is isophorone diisocyanate.

[0020] Further, the chain extender is one or several of 2,2-dimethylol propionic acid, 1-4 butanediol, ethylenediamine, 2,2'-diamino diphenyl disulfide.

[0021] Further, the neutralizing agent is triethylamine.

[0022] Further, the acrylic monomer is one of hydroxyethyl methacrylate, hydroxypropyl methacrylate, pentaerythritol triacrylate.

[0023] Further, the metal ion is divalent zinc ion.

[0024] Further, the coupling agent is one of gamma-aminopropyl triethoxysilane, mercaptan, gamma-glycidyl ether oxygen propyl trimethoxysilane.

[0025] Further, the photoinitiator is one of 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and diphenyl-(2,4,6-trimethylbenzoyl).

[0026] The bio-based modified high self-repairing bipolar plate gas path sealant adhesive provided by the application mainly selects a bio-based modified waterborne polyurethane as a raw material. The polyurethane is a block polymer composed of polyols and isocyanate, wherein the polyols are connected by chemical bonds (-C-C-, -C-O-) to provide the polyurethane with good toughness, and the isocyanate and small molecule chain extender endow the PUR with higher rigidity. The connection of the soft segment and the hard segment enables the polyurethane material to simultaneously have excellent mechanical properties and flexibility. The structure of the vegetable oil is very superior. Firstly, the vegetable oil contains a polyhydroxy structure and can directly react with isocyanate to form a micro-crosslinked structure, thereby improving the water resistance and mechanical properties of the WPU. Secondly, the vegetable oil structure has multiple unsaturated bonds, which can be modified by combining with acrylate and the modified WPU can be ultraviolet cured or LED light cured, thereby obtaining a product with good mechanical properties. The bio-based modified waterborne polyurethane has advantages in environmental protection and transportation due to its good low-temperature stability and strong mechanical properties, and has high application value.

[0027] The application provides a preparation method of the bio-based modified waterborne polyurethane.

[0028] After 20-53 parts of bio-based polyols, 20-55 parts of polymeric polyols and 3-7 parts of a chain extender are fully mixed and dried, 30-60 parts of diisocyanate and 0.1-0.5 parts of a catalyst are added, and the mixture is reacted at 80-85 DEG C. for 1-3 h. After the system is cooled, 3-5 parts of a neutralizing agent are added. Then, 2-5 parts of a chain extender are added, and the chain extension is carried out at 20-30 DEG C. for 30-50 min. to obtain a waterborne polyurethane prepolymer. 5-15 parts of an acrylic monomer and 1-2 parts of a metal ion are added to the system, and the mixture is reacted at 65-70 DEG C. for 2-3 h. Finally, deionized water is added and stirred intensively to obtain the bio-based modified waterborne polyurethane.

[0029] The bio-based modified waterborne polyurethane is dispersed and stirred with 5-6 parts of a coupling agent and 2-5 parts of a photoinitiator to obtain a colloid. The colloid is placed in a vacuum defoaming machine for defoaming to obtain the bio-based modified high self-repairing bipolar plate gas path sealant adhesive.

[0030] According to another aspect of the application, the application also provides application of the bio-based modified high self-repairing bipolar plate gas path sealant adhesive in bipolar plate gas path sealing.

[0031] The bio-based modified high self-repairing bipolar plate gas path sealant adhesive provided by the application has the following advantages.

[0032] 1. The present application uses bio-based modified waterborne polyurethane as raw material, so that the adhesive has the environmental protection performance of vegetable oil and waterborne polyurethane at the same time. The vegetable oil-based polyurethane is prepared by using natural renewable vegetable oil as raw material, and the functional vegetable oil is used to replace the traditional petroleum-based polyol as the raw material for synthesizing WPU, thereby reducing the use of fossil raw materials.

[0033] 2. The present application develops a new type of high self-repairing waterborne polyurethane adhesive based on the synergistic crosslinking effect of hydrogen bond and Zn(II) coordination bond. In the system, the hydrogen bond as a weak dynamic bond has reversibility, which can quickly recombine after breaking, so that the adhesive has excellent self-repairing ability and mechanical properties. The highly reversible but weak Zn(II) coordination bond as a strong dynamic bond not only significantly improves the self-repairing performance of the adhesive, but also makes the adhesive have the characteristics of moderate hardness and high elasticity. Through the mutual influence of the strong and weak dynamic bonds, the stability and elasticity of the material are effectively enhanced to achieve the ideal state of design.

[0034] 3. The present application adds acrylic acid modification, which utilizes the reaction characteristics of the acrylic acid and the photoinitiator to make the adhesive achieve ultraviolet curing. The product requires less energy and has fast curing time, which greatly reduces the production cost. At the same time, it is applied to the sealing and bonding of bipolar plate gas path, perfectly meeting the requirements of environmental protection and low cost. DETAILED DESCRIPTION

[0035] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application are described in detail below. In the following description, a large number of specific details are set forth in order to fully understand the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the scope of the present application, therefore the present application is not limited by the specific embodiments disclosed below.

[0036] The present application preferably comprises the following components by mass fraction:

[0037] Polymer polyol 20-55 parts;

[0038] Bio-based polyol 20-53 parts;

[0039] Diisocyanate 30-60 parts;

[0040] Catalyst 0.1-0.5 parts;

[0041] Chain extender 5-12 parts;

[0042] Neutralizing agent 3-5 parts;

[0043] Acrylic monomer 5-15 parts;

[0044] Metal ion 1-2 parts;

[0045] Deionized water 100-202 parts;

[0046] Coupling agent 5-6 parts;

[0047] Photoinitiator 2-5 parts.

[0048] The preparation steps of the above-mentioned bio-based modified high self-repairing bipolar plate gas path seal adhesive are as follows:

[0049] After 20-53 parts of bio-based polyol, 20-55 parts of polymer polyol and 3-7 parts of chain extender are fully mixed and dried, 30-60 parts of diisocyanate and 0.1-0.5 parts of catalyst are added and reacted at 80-85℃ for 1-3h, the system is cooled and 3-5 parts of neutralizing agent is added; Then add 2-5 parts of chain extender, chain extend at 20-30℃ for 30-50min, get waterborne polyurethane prepolymer. In the system, add 5-15 parts of acrylic monomer and 1-2 parts of metal ion, react at 65-70℃ for 2-3h, finally use deionized water to stir intensively, get bio-based modified waterborne polyurethane;

[0050] The bio-based modified waterborne polyurethane prepared above is dispersed and stirred with 5-6 parts of coupling agent and 2-5 parts of photoinitiator to get colloid, the colloid is put into vacuum degassing machine to degas, and bio-based modified high self-repairing bipolar plate gas path seal adhesive is prepared.

[0051] Specifically, the polymer polyol is one or both of polyether polyol or polycarbonate polyol.

[0052] Specifically, the bio-based polyol is one of alcoholysis linseed oil polyol, castor oil, palm oil-based polyol, and acetic ester corn starch polyol.

[0053] The alcoholysis linseed oil polyol is synthesized as follows:

[0054]

[0055] Specifically includes the following steps:

[0056] First, a certain amount of pure linseed oil and trihydroxymethyl propane are weighed accurately and added into a 250ml four-necked flask with mechanical stirring, condensation reflux device and thermometer under the protection of dry nitrogen, secondly, a small amount of PBO is added as catalyst, the reaction temperature is adjusted to 240-245℃, and the reaction is stirred for 4-4.5h in an oil bath. In the reaction, the glycerol triesters in pure linseed oil are subjected to alcoholysis, the hydroxyl groups in the reaction system are redistributed on the carboxyl groups to form rearranged linseed oil triesters. Finally, impurities are removed by washing and drying to obtain alcoholysis linseed oil polyol.

[0057] The synthesis of the palm oil-based polyol is as follows:

[0058]

[0059] Specifically, the steps include:

[0060] In a four-necked flask, add epoxidized palm oil, prepare condenser, thermometer, mechanical stirring and constant pressure dropping funnel, slowly warm the oil bath to 70℃, take an appropriate amount of lactic acid and add it to the constant pressure dropping funnel, then adjust the mechanical stirring speed to 1000rpm, then slowly drop the lactic acid in the funnel into the flask, and drop it in 20min; continue to warm to 90℃, stir for 5h, and add a certain amount of triphenyl phosphine during stirring; sample every interval to determine the acid value, until the acid value of the system no longer changes, stop the reaction.

[0061] The synthesis of the acetate corn starch-based polyol is as follows:

[0062]

[0063] Specifically, the steps include:

[0064] Under a nitrogen atmosphere, first add the corresponding amount of corn starch and acetic acid into a three-necked flask with magnetic stirring, continuously stir and adjust the temperature to 75-80℃, then add the corresponding fraction of esterification agent acetic anhydride and continue to react, then add a small amount of methyl sulfonic acid to catalyze the reaction, after stirring for 2-2.5h, add an appropriate amount of deionized water to terminate the reaction, finally obtain the crude product of starch-based, then put the crude product into a Buchner funnel for reduced pressure filtration, in order to remove excess acetic acid and acetic anhydride, wash the product with deionized water, and then dry to obtain acetate corn starch.

[0065] Specifically, the diisocyanate is isophorone diisocyanate.

[0066] Specifically, the chain extender is one or more of 2,2-dimethylol propionic acid, 1-4 butanediol, ethylenediamine, and 2,2'-diaminodiphenyl disulfide.

[0067] Specifically, the neutralizing agent is triethylamine.

[0068] Specifically, the acrylic monomer is one of hydroxyethyl methacrylate, hydroxypropyl methacrylate, pentaerythritol triacrylate.

[0069] Specifically, the metal ion is divalent zinc ion.

[0070] Specifically, the coupling agent is one of γ-aminopropyl triethoxysilane, mercaptan, γ-glycidoxypropyl trimethoxysilane.

[0071] Specifically, the photoinitiator is one of 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, diphenyl-(2,4,6-trimethylbenzoyl).

[0072] This will be further illustrated according to Examples 1-8 as follows:

[0073] It should be noted in advance that the test methods used by the bio-based modified high self-repairing bipolar plate gas path seal adhesive described in the following Examples 1-8 are as follows:

[0074] The adhesive samples obtained in Examples 1-8 were dropped and pressed on a clean teflon mold of a specific size, dried at room temperature for 12h to evaporate water, and then the samples were placed in a track-type UV curing device and exposed to ultraviolet light of a LED lamp with a main wavelength of 365nm for 3min to cure, and finally the test samples were obtained.

[0075] 1. Viscosity test: a rotary viscometer (NDJ-1) was used for testing.

[0076] 2. Mechanical property test: the test sample was taken, and the hardness, tensile strength and elongation at break of the adhesive in the sample were tested by a dynamic mechanical property analyzer (Q-800) according to the test standard GB / T528-2009.

[0077] 3. Air tightness test: the initial pressure value and temperature of the adhesive in the sample were measured, a new pressure value was obtained by using a differential pressure type air tightness detector (GOEL-350), and the temperature after testing was measured, the leakage rate of the adhesive was calculated, and the air tightness of the adhesive was evaluated. The leakage rate greater than 0.20% indicates that the air tightness of the sample is unqualified.

[0078] 4. High temperature resistance and elasticity test: measure the initial height of the sample (unit: mm), the height after 50 times pressing, the height after passing through the 260℃ reflow furnace twice, the height after 50 times pressing after passing through the 260℃ reflow furnace twice, calculate the shrinkage rate (%) of the sample before the reflow furnace, after the reflow furnace, and after the reflow furnace and 50 times pressing, and observe the appearance of the sample after pressing, and judge the high temperature resistance and elasticity of the sample.

[0079] Example 1:

[0080] The present embodiment provides a high self-repairing bipolar plate gas path sealing adhesive modified by alcoholysis of linseed oil, and the preparation raw materials of the adhesive include the following components calculated by mass fraction:

[0081] alcoholysis of linseed oil polyol 35 parts;

[0082] isophorone diisocyanate 30 parts;

[0083] stannous octoate 0.5 parts;

[0084] 2,2-dimethylol propionic acid 5 parts;

[0085] 1,4-butanediol 2 parts;

[0086] triethylamine 4 parts;

[0087] ethylenediamine 5 parts;

[0088] pentaerythritol triacrylate 10 parts;

[0089] zinc chloride 2 parts;

[0090] deionized water 100 parts;

[0091] γ-glycidyl ether propyltrimethoxysilane 5 parts;

[0092] 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone 5 parts.

[0093] The preparation method of the alcoholysis of linseed oil polyol is as follows:

[0094] First, accurately weigh a certain amount of pure linseed oil and trihydroxymethyl propane according to the measured feeding ratio, and add them into a 250ml four-necked flask with mechanical stirring, condensation reflux device and thermometer under the protection of dry nitrogen, secondly, continue to add a small amount of PBO as catalyst, adjust the reaction temperature to 240℃ oil bath heating and stirring for 4h. In the reaction, the hydroxyl groups in the pure linseed oil triglyceride are rearranged to form a rearranged linseed oil triester by alcoholysis of the hydroxyl groups in the reaction carboxyl groups. Finally, impurities are removed by washing and drying to obtain alcoholysis of linseed oil polyol.

[0095] The preparation method of the embodiment specifically comprises the following steps:

[0096] First, 35 parts of alcoholysis flax oil polyol, 5 parts of 2, 2-dimethylol propionic acid and 2 parts of 1, 4-butanediol were put into a 250 mL three-necked flask with a mechanical stirrer and a condenser, heated to 120℃ in an oil bath under N2 atmosphere, and dried for 2 h. Then, the temperature of the oil bath was reduced to 70℃, 30 parts of isophorone diisocyanate and 0.5 parts of stannous octoate were added dropwise into the mixture, the temperature was raised to 80℃, and then reacted at 80℃ for 2 h. The system was cooled to 40℃, 4 parts of triethylamine was added and stirred for 50 min. According to the above steps, 5 parts of ethylenediamine was added, and chain extension was carried out at 30℃ for 30 min to obtain an aqueous polyurethane prepolymer. After the chain extension process, 10 parts of pentaerythritol triacrylate and 2 parts of zinc chloride were added to the system, and reacted at 70℃ for 3 h. Finally, the prepolymer was dispersed by strong stirring with deionized water at 1500 rpm for 1 h to obtain an alcoholysis flax oil modified aqueous polyurethane.

[0097] The alcoholysis flax oil modified aqueous polyurethane prepared above was added to a vacuum stirrer along with 5 parts of γ-glycidoxypropyltrimethoxysilane and 5 parts of 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone, and centrifugal dispersion was carried out at 700 rpm for 50 s, 1300 rpm for 500 s, and 700 rpm for 50 s to obtain a colloid. After stirring, the colloid was placed in a vacuum defoaming machine and defoamed at 1500 rpm for 10 min. After defoaming, an alcoholysis flax oil modified high self-repairing bipolar gas path sealant adhesive was obtained.

[0098] Embodiment 2:

[0099] The embodiment provides an alcoholysis flax oil modified high self-repairing bipolar gas path sealant adhesive, and raw materials for preparing the adhesive include the following components in parts by mass:

[0100] alcoholysis flax oil polyol 20 parts;

[0101] polyether polyol 10 parts;

[0102] polycarbonate polyol 10 parts;

[0103] isophorone diisocyanate 30 parts;

[0104] 2, 2-dimethylol propionic acid 5 parts;

[0105] ethylenediamine 5 parts;

[0106] 2, 2'-diaminodiphenyl disulfide 3 parts;

[0107] dibutyltin dilaurate 0.5 parts;

[0108] Triethylamine 4 parts;

[0109] Pentaerythritol triacrylate 10 parts;

[0110] Zinc chloride 2 parts;

[0111] Deionized water 100 parts;

[0112] Gamma-aminopropyl triethoxysilane 5 parts;

[0113] 2-Hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone 5 parts.

[0114] The preparation method of the alcoholysis linseed oil polyol is as follows:

[0115] First, a certain amount of pure linseed oil and trihydroxymethyl propane are accurately weighed and added into a 250 ml four-necked flask with mechanical stirring, condensation reflux device and thermometer under the protection of dry nitrogen according to the measured feeding ratio, a small amount of PBO is continuously added as a catalyst in the second step, the reaction temperature is adjusted to 240 DEG C, and oil bath heating and stirring are carried out for 4 h. In the reaction, the hydroxyl groups in the reaction system are redistributed on the carboxyl groups by alcoholysis of pure linseed oil triglyceride, and rearranged linseed oil triglyceride is generated. Finally, impurities are removed by washing and drying to obtain alcoholysis linseed oil polyol.

[0116] The preparation method of the embodiment specifically includes the following steps:

[0117] First, 20 parts of alcoholysis linseed oil polyol, 10 parts of polyether polyol, 10 parts of polycarbonate polyol, 5 parts of 2,2-dihydroxymethyl propionic acid and 3 parts of 2,2'-diamino diphenyl disulfide are put into a 250 mL three-necked flask with a mechanical stirrer and a condenser, the oil bath is heated to 120 DEG C under N2 atmosphere, and drying is carried out for 2 h. Subsequently, the temperature of the oil bath is reduced to 70 DEG C, 30 parts of isophorone diisocyanate and 0.5 parts of dibutyltin dilaurate are added dropwise into the mixture, and the temperature is raised to 85 DEG C, and then the reaction is carried out at 85 DEG C for 2 h. The system is cooled to 50 DEG C, 4 parts of triethylamine are added and stirred for 50 min. According to the above steps, 5 parts of ethylenediamine are added, and chain extension is carried out at 30 DEG C for 50 min to obtain a waterborne polyurethane prepolymer. After the chain extension process is completed, 10 parts of pentaerythritol triacrylate and 2 parts of zinc chloride are added into the system, and the reaction is carried out at 70 DEG C for 3 h. Finally, the prepolymer is dispersed by using deionized water to strongly stir at a speed of 1500 rpm for 1 h to obtain alcoholysis linseed oil modified waterborne polyurethane.

[0118] ​The alcoholysis of the linseed oil modified waterborne polyurethane prepared above and 5 parts of γ-aminopropyl triethoxysilane and 5 parts of 2-hydroxy-4-(2-hydroxyethoxy)-2-methylpropiophenone were added into a vacuum stirring machine for centrifugal dispersion, centrifugal stirring at 700 rpm for 50 s, stirring at 1300 rpm for 500 s, and centrifugal stirring at 700 rpm for 50 s to obtain a colloid. After stirring, the colloid was placed into a vacuum defoaming machine for centrifugal defoaming at 1500 rpm for 10 min. After defoaming, the alcoholysis of the linseed oil modified waterborne polyurethane with high self-repairing bipolar plate gas path sealant adhesive was obtained.

[0119] Example 3:

[0120] The present example provides a castor oil based modified high self-repairing bipolar plate gas path sealant adhesive, and the preparation raw materials of the sealant adhesive include the following components calculated by mass fraction:

[0121] Castor oil 35 parts;

[0122] Isophorone diisocyanate 35 parts;

[0123] Polyether polyol 50 parts;

[0124] 2,2-dimethylol propionic acid 5 parts;

[0125] 1-4 butanediol 2 parts;

[0126] Dibutyltin dilaurate 0.1 parts;

[0127] Ethylene diamine 5 parts;

[0128] Triethylamine 4 parts;

[0129] 3-hydroxyethyl methacrylate 10 parts;

[0130] Zinc chloride 2 parts;

[0131] Deionized water 155 parts;

[0132] Thiol 5 parts;

[0133] 2-hydroxy-2-methyl-1-phenyl-1-propanone 4 parts.

[0134] The preparation method of the present example specifically includes the following steps:

[0135] First, 35 parts of castor oil, 50 parts of polyether polyol, 5 parts of 2,2-dimethylol propionic acid and 2 parts of 1,4-butanediol were put into a 250 ml three-necked flask with a mechanical stirrer and a condenser, and heated to 120°C in an oil bath under N2atmosphere for 2 h. Then, the temperature of the oil bath was lowered to 70°C, 35 parts of isophorone diisocyanate and 0.1 part of dibutyl tin dilaurate were added dropwise into the container and the temperature was raised to 80°C, and reacted at 80°C for 2 h. The system was cooled to 40°C, 4 parts of triethylamine was added and stirred for 50 min. Then, 5 parts of ethylenediamine was added according to the above procedure, and chain extension was carried out at 30°C for 30 min to obtain an aqueous polyurethane prepolymer. After the chain extension process, 10 parts of 3-hydroxyethyl methacrylate and 2 parts of zinc chloride were added into the system and reacted at 70°C for 3 h. Finally, the castor oil-based modified aqueous polyurethane was obtained by stirring with deionized water at a speed of 1500 rpm for 1 h.

[0136] The castor oil-based modified aqueous polyurethane prepared above was added into a vacuum stirrer with 5 parts of mercaptan and 4 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone for centrifugal dispersion, centrifugal stirring at 700 rpm for 50 s, 1300 rpm for 500 s and 700 rpm for 50 s to obtain a colloid. After stirring, the colloid was put into a vacuum defoaming machine for centrifugal defoaming at a speed of 1500 rpm for 10 min. After defoaming, the castor oil-based modified high self-repairing bipolar plate gas path sealant was obtained.

[0137] Example 4:

[0138] The present example provides a castor oil-based modified high self-repairing bipolar plate gas path sealant, and the raw materials for preparing the sealant include the following components in parts by mass:

[0139] Castor oil 40 parts;

[0140] Isophorone diisocyanate 40 parts;

[0141] Polyether polyol 35 parts;

[0142] Polycarbonate polyol 20 parts;

[0143] 2,2-dimethylol propionic acid 5 parts;

[0144] 1-4 butanediol 2 parts;

[0145] Dibutyl tin dilaurate 0.1 part;

[0146] Ethylenediamine 5 parts;

[0147] Triethylamine 4 parts;

[0148] 3-hydroxyethyl methacrylate 10 parts;

[0149] Zinc chloride 2 parts;

[0150] Deionized water 180 parts;

[0151] Vinyl trimethyl silane 5 parts;

[0152] 2-Hydroxy-2-methyl-l-phenyl-l-propanone 4 parts.

[0153] The preparation method of this embodiment specifically includes the following steps:

[0154] First, 40 parts of castor oil, 35 parts of polyether polyol, 20 parts of polycarbonate polyol, 5 parts of 2,2-dimethylol propionic acid and 2 parts of 1,4-butanediol were put into a 250 ml three-necked flask with a mechanical stirrer and a condenser, and the oil bath was heated to 120°C under N2atmosphere for 2 h. Then, the temperature of the oil bath was lowered to 70°C, 40 parts of isophorone diisocyanate and 0.1 part of dibutyl tin dilaurate were added to the container and the temperature was raised to 80°C, and then reacted at 80°C for 2 h. The system was cooled to 40°C, 4 parts of triethylamine was added and stirred for 50 min. According to the above steps, 5 parts of ethylenediamine was added and chain extended at 30°C for 30 min to obtain an aqueous polyurethane prepolymer. After the chain extension process, 10 parts of 3-hydroxyethyl methacrylate and 2 parts of zinc chloride were added to the system and reacted at 70°C for 3 h. Finally, the prepolymer was dispersed by strong stirring with deionized water at a speed of 1500 rpm for 1 h to obtain a castor oil-based modified aqueous polyurethane.

[0155] The castor oil-based modified aqueous polyurethane emulsion prepared above was added to a vacuum stirrer along with 5 parts of vinyl trimethyl silane and 4 parts of 2-hydroxy-2-methyl-l-phenyl-l-propanone for centrifugal dispersion. The stirring speed was 700 rpm for 50 s, 1300 rpm for 500 s and 700 rpm for 50 s to obtain a colloid. After the stirring was completed, the colloid was placed in a vacuum defoaming machine and defoamed at a speed of 1500 rpm for 10 min. After defoaming, a castor oil-based modified high self-repairing bipolar gas path sealant adhesive was obtained.

[0156] Example 5:

[0157] This embodiment provides a palm oil-based modified high self-repairing bipolar gas path sealant adhesive. The raw materials for preparing the adhesive include the following components in parts by mass:

[0158] Polyether polyol 15 parts;

[0159] Palm oil-based polyol 20 parts;

[0160] Isophorone diisocyanate 35 parts;

[0161] Dibutyltin dilaurate 0.1 part;

[0162] 2,2-dimethylol propionic acid 5 parts;

[0163] Triethylamine 4 parts;

[0164] Ethylene diamine 5 parts;

[0165] Hydroxyethyl methacrylate 10 parts;

[0166] Zinc chloride 1 part;

[0167] Deionized water 157 parts;

[0168] γ-aminopropyl triethoxysilane 5 parts;

[0169] 2-hydroxy-2-methyl-1-phenyl-1-propanone 2 parts.

[0170] The palm oil-based polyol is prepared by the following method:

[0171] A four-necked flask is charged with epoxidized palm oil, a condenser, a thermometer, mechanical stirring, and a constant pressure dropping funnel. The oil bath is slowly heated to 70°C, and an appropriate amount of lactic acid is added to the constant pressure dropping funnel. The mechanical stirring speed is adjusted to 1000 rpm, and then the lactic acid in the dropping funnel is slowly added to the flask. The addition is completed within 20 min. The temperature is continuously increased to 90°C, and stirring is performed for 5 h. A certain amount of triphenyl phosphine is added during the stirring process. The acid value is measured at intervals, and the reaction is stopped when the acid value of the system no longer changes. After the reaction is completed, cyclohexane is mixed with the product for extraction. After the mixture is allowed to stand and separate into layers, the water layer is discharged. Deionized water is used to repeat the washing process for 3 times. After cyclohexane is recovered by normal pressure distillation, the palm oil-based polyol is obtained by vacuum distillation.

[0172] The preparation method of the embodiment specifically includes the following steps:

[0173] First, 20 parts of palm oil-based polyol, 15 parts of polyether polyol, and 5 parts of 2,2-dimethylol propionic acid are placed in a 250 mL three-necked flask with a mechanical stirrer and a condenser. The oil bath is heated to 120°C under N2 atmosphere, and drying is performed for 2 h. Subsequently, the temperature of the oil bath is reduced to 75°C, 35 parts of diisocyanate and 0.1 part of dibutyltin dilaurate are added to the mixture, and the temperature is increased to 85°C. Then, the reaction is performed at 85°C for 2 h. The system is cooled to 40°C, 4 parts of triethylamine are added, and stirring is performed for 50 min. According to the above steps, 5 parts of ethylene diamine are added, and chain extension is performed at 30°C for 30 min to obtain an aqueous polyurethane prepolymer. After the chain extension process is completed, 10 parts of hydroxyethyl methacrylate and 1 part of zinc chloride are added to the system, and the reaction is performed at 70°C for 3 h. Finally, the prepolymer is dispersed by strong stirring with deionized water at a speed of 1500 rpm for 1 h to obtain an aqueous polyurethane emulsion.

[0174] The preparation method of the waterborne polyurethane adhesive is as follows:

[0175] The prepared waterborne polyurethane emulsion, 5 parts of γ-aminopropyl triethoxysilane, and 2 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone are added into a vacuum stirrer for centrifugal dispersion, centrifugal stirring at 700 rpm for 50 s, stirring at 1300 rpm for 500 s, and centrifugal stirring at 700 rpm for 50 s to obtain a colloid. After stirring, the colloid is placed into a vacuum defoaming machine for centrifugal defoaming at a speed of 1500 rpm for 10 min. After defoaming, a palm oil-based modified high self-repairing bipolar plate gas path sealing adhesive is obtained.

[0176] Example 6:

[0177] The present embodiment provides a palm oil-based modified high self-repairing bipolar plate gas path sealing adhesive, and the preparation raw materials of the adhesive include the following components calculated by mass fraction:

[0178] Polycarbonate polyol 20 parts;

[0179] Palm oil-based polyol 20 parts;

[0180] Isophorone diisocyanate 60 parts;

[0181] Dibutyltin dilaurate 0.1 part;

[0182] 2,2-dimethylol propionic acid 5 parts;

[0183] Triethylamine 4 parts;

[0184] Ethylene diamine 5 parts;

[0185] Hydroxypropyl methacrylate 10 parts;

[0186] Zinc chloride 1 part;

[0187] Deionized water 202 parts;

[0188] γ-aminopropyl triethoxysilane 6 parts;

[0189] 2-hydroxy-2-methyl-1-phenyl-1-propanone 2 parts.

[0190] The preparation method of the palm oil-based polyol is as follows:

[0191] In a four-necked flask, add epoxidized palm oil, prepare condenser, thermometer, mechanical stirring and constant pressure dropping funnel, slowly heat the oil bath to 70℃, take a proper amount of lactic acid and add to the constant pressure dropping funnel, adjust the mechanical stirring speed to 1000rpm, then slowly drop the lactic acid in the funnel into the flask, drop for 20min; continue to heat to 90℃, stir for 5h, and add a certain amount of triphenyl phosphine during stirring; take sample every interval to determine the acid value until the acid value of the system no longer changes, then stop the reaction. After the reaction is completed, take cyclohexane to mix with the product for extraction, after standing and separating, take out the water layer. Take deionized water to repeat washing for 3 times. After recovering cyclohexane by normal pressure distillation, recover palm oil based polyol by reduced pressure distillation.

[0192] The preparation method of the embodiment specifically includes the following steps:

[0193] First, put 20 parts of palm oil based polyol, 20 parts of polycarbonate polyol and 5 parts of 2,2-dimethylol propionic acid into a 250mL three-necked flask with a mechanical stirrer and a condenser, heat the oil bath to 120℃ under N2 atmosphere, dry for 2h. Then, reduce the temperature of the oil bath to 75℃, drop 60 parts of diisocyanate and 0.1 part of dibutyltin dilaurate into the mixture and raise the temperature to 85℃, then react for 2h at 85℃. Cool the system to 40℃, add 4 parts of triethylamine and stir for 50min. Then, according to the above steps, add 5 parts of ethylenediamine, and chain extend for 30min at 30℃ to obtain an aqueous polyurethane prepolymer. After the chain extension process is completed, add 10 parts of hydroxypropyl methacrylate and 1 part of zinc chloride to the system, and react for 3h at 70℃. Finally, disperse the prepolymer by strong stirring with deionized water at a speed of 1500rpm for 1h to obtain a palm oil based modified aqueous polyurethane.

[0194] Put the palm oil based modified aqueous polyurethane prepared above, 6 parts of γ-aminopropyl triethoxysilane and 2 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone into a vacuum stirrer for centrifugal dispersion, centrifugal stir at 700rpm for 50s, 1300rpm for 500s and 700rpm for 50s to obtain a colloid. After stirring is completed, put the colloid into a vacuum defoaming machine for centrifugal defoaming at a speed of 1500rpm for 10min. After defoaming is completed, a palm oil based modified high self-repairing bipolar gas path sealant adhesive is obtained.

[0195] Example 7:

[0196] The embodiment provides a starch based modified high repairable bipolar gas path sealant adhesive, and raw materials for preparing the sealant adhesive include the following components in parts by mass:

[0197] Acetate corn starch polyol 53 parts;

[0198] Isophorone diisocyanate 35 parts;

[0199] Dibutyltin dilaurate 0.5 parts;

[0200] 2,2-dimethylol propionic acid 4 parts;

[0201] Triethylamine 3 parts;

[0202] 2,2'-diaminodiphenyl disulfide 2 parts;

[0203] Hydroxypropyl methacrylate 10 parts;

[0204] Deionized water 140 parts;

[0205] γ-aminopropyl triethoxysilane 5 parts;

[0206] Diphenyl-(2,4,6-trimethylbenzoyl) phosphine oxide 2 parts.

[0207] The preparation method of the acetate corn starch-based polyol is as follows:

[0208] Under a nitrogen atmosphere, a three-necked flask equipped with a magnetic stirrer was charged with a certain amount of corn starch and acetic acid, which was continuously stirred and heated to 75°C, and then a corresponding amount of acetic anhydride was added dropwise, followed by the addition of a small amount of methyl sulfonic acid. After stirring for two hours, deionized water was added to terminate the reaction, and a crude starch-based product was obtained. Then, it was placed in a Buchner funnel for vacuum filtration. In order to remove excess acetic acid and acetic anhydride, the product was washed with deionized water and then dried to obtain the acetate corn starch-based polyol.

[0209] The preparation method of the present embodiment specifically includes the following steps:

[0210] First, 53 parts of acetate corn starch polyol and 4 parts of 2,2-dimethylol propionic acid were placed in a 250 mL three-necked flask equipped with a mechanical stirrer and a condenser. Under a N2 atmosphere, the oil bath was heated to 120°C and dried for 2 h. Then, the temperature of the oil bath was lowered to 70°C, 35 parts of isophorone diisocyanate and 0.5 parts of dibutyltin dilaurate were added dropwise to the mixture, and the temperature was raised to 80°C. Then, the reaction was carried out at 80°C for 2 h. The system was cooled to 40°C, 3 parts of triethylamine were added and stirred for 50 min to neutralize the carboxyl groups in the 2,2-dimethylol propionic acid. According to the above steps, 2 parts of 2,2'-diaminodiphenyl disulfide were added, and chain extension was carried out at 30°C for 30 min to obtain an aqueous polyurethane prepolymer. After the chain extension process was completed, 10 parts of hydroxypropyl methacrylate were added to the system, and the reaction was carried out at 70°C for 3 h. Finally, the prepolymer was dispersed by stirring vigorously with deionized water at a speed of 1500 rpm for 1 h to obtain a starch-based modified aqueous polyurethane emulsion.

[0211] The starch-based modified waterborne polyurethane emulsion prepared above was added into a vacuum stirrer with 5 parts of γ-aminopropyl triethoxysilane and 2 parts of diphenyl-(2,4,6-trimethylbenzoyl) phosphine oxide, centrifugal dispersion was carried out at 700 rpm for 50 s, 1300 rpm for 500 s and 700 rpm for 50 s to obtain a waterborne polyurethane colloid. After stirring, the colloid was placed into a vacuum defoaming machine and defoamed at 1500 rpm for 10 min to obtain a starch-based modified high self-repairing ultraviolet-curable waterborne polyurethane adhesive.

[0212] Example 8:

[0213] The present example provides a starch-based modified high-repairing bipolar plate gas path sealing adhesive, the preparation raw materials of the adhesive include the following components in parts by mass:

[0214] Acetate corn starch polyol 45 parts;

[0215] Isophorone diisocyanate 33 parts;

[0216] Dibutyltin dilaurate 0.5 parts;

[0217] 2,2-dimethylol propionic acid 4 parts;

[0218] Triethylamine 3 parts;

[0219] Ethylene diamine 2 parts;

[0220] 2,2'-diamino diphenyl disulfide 2 parts;

[0221] Hydroxyethyl methacrylate 10 parts;

[0222] Deionized water 140 parts;

[0223] γ-aminopropyl triethoxysilane 6 parts;

[0224] Diphenyl-(2,4,6-trimethylbenzoyl) phosphine oxide 2 parts.

[0225] The preparation method of the acetate corn starch polyol is as follows:

[0226] Under a nitrogen atmosphere, a three-necked flask equipped with a magnetic stirrer was added with a certain amount of corn starch and acetic acid, which was continuously stirred and heated to 75°C, then the corresponding parts of acetic anhydride were added dropwise, followed by the addition of a small amount of methyl sulfonic acid, and after stirring for two hours, deionized water was added to terminate the reaction, to obtain a crude starch-based product, which was then placed into a Buchner funnel for reduced pressure filtration, and after washing the product with deionized water, it was dried to obtain the acetate corn starch polyol.

[0227] The preparation method of the embodiment specifically comprises the following steps:

[0228] First, 45 parts of acetate corn starch polyol, 4 parts of 2, 2-dimethylol propionic acid were put into a 250 mL three-necked flask with a mechanical stirrer and a condenser, heated to 120°C in an oil bath under N2 atmosphere, and dried for 2 h. Then, the temperature of the oil bath was reduced to 70°C, 33 parts of isophorone diisocyanate and 0.5 parts of dibutyltin dilaurate were added dropwise into the mixture, and the temperature was raised to 80°C, and then reacted at 80°C for 2 h. The system was cooled to 40°C, 3 parts of triethylamine was added and stirred for 50 min to neutralize the carboxyl group in 2, 2-dimethylol propionic acid. According to the above steps, 2 parts of ethylenediamine and 2 parts of 2, 2'-diaminodiphenyl disulfide were added, and chain extension was carried out at 30°C for 50 min to obtain an aqueous polyurethane prepolymer. After the chain extension process, 10 parts of hydroxyethyl methacrylate was added to the system and reacted at 70°C for 3 h. Finally, the prepolymer was dispersed by stirring at 1500 rpm for 1 h with deionized water to obtain a starch-based modified aqueous polyurethane.

[0229] The starch-based modified aqueous polyurethane prepared above was added to a vacuum stirrer for centrifugal dispersion, centrifugal stirring at 700 rpm for 50 s, 1300 rpm for 500 s, and 700 rpm for 50 s to obtain an aqueous polyurethane colloid. After stirring, the colloid was placed in a vacuum defoaming machine and centrifuged at 1500 rpm for 10 min to obtain a starch-based modified high self-repairing ultraviolet-curable aqueous polyurethane adhesive.

[0230] The air tightness of the bio-based modified high self-repairing ultraviolet-curable aqueous polyurethane adhesive prepared in Examples 1-8 above was tested, and the results are shown in Table 1 below:

[0231] Table 1: Comparison of leakage rates of Examples 1-8

[0232]

[0233] The air tightness of the bio-based modified high self-repairing ultraviolet-curable aqueous polyurethane adhesive prepared in Examples 1-8 above was tested, and the results are shown in Table 1 below:

[0234] The mechanical properties of the bio-based modified high self-repairing ultraviolet-curable aqueous polyurethane adhesive prepared in Examples 1-8 above were tested, and the results are shown in Table 2 below:

[0235] Table 2: Comparison of mechanical properties of Examples 1-8

[0236]

[0237] The above results show that the embodiments 1-8 of the present application can maintain good mechanical properties.

[0238] The shrinkage rate (%) of the bio-based modified high self-repairing ultraviolet light cured waterborne polyurethane adhesive prepared in the above embodiments 1-8 was tested, and the results are shown in Table 3 below:

[0239] Table 3: Shrinkage rate (%) comparison of embodiments 1-8

[0240]

[0241] The above results show that after the reflow soldering furnace and then continuing to compress 50 times, the average shrinkage rate of the samples of embodiments 1-8 compared with the initial state is slightly decreased, which proves that the sample has slightly deformed. At the same time, there is no obvious change in appearance after 50 times of pressing, which still shows that the adhesive has good high temperature resistance and elasticity, and has good self-repairing effect.

[0242] It can be understood that the above specific embodiments are further illustrations of the present application and are not used to limit the protection scope of the present application. All other decorations and modifications obtained by those skilled in the art without creative labor belong to the protection scope of the present application.

Claims

1. A bio-based modified bipolar plate gas path sealing adhesive with high self-healing properties, characterized in that, The raw materials for preparation include the following components in parts by mass: 20-55 parts of polymeric polyol; 20-53 parts of bio-based polyols; 30-60 parts of diisocyanate; Catalyst 0.1-0.5 parts; 5-12 parts of chain extender; 3-5 parts neutralizing agent; 5-15 parts of acrylic monomer; 1-2 parts of metal ions; 100-202 parts deionized water; 5-6 parts of coupling agent; 2-5 parts of photoinitiator; The metal ion is a divalent zinc ion; The preparation method of the bio-based modified highly self-healing bipolar plate gas path sealing adhesive includes the following steps: After thoroughly mixing 20-53 parts of bio-based polyol, 20-55 parts of polymeric polyol, and 3-7 parts of chain extender, and drying the mixture, 30-60 parts of diisocyanate and 0.1-0.5 parts of catalyst were added, and the mixture was reacted at 80-85℃ for 1-3 hours. After cooling the system, 3-5 parts of neutralizing agent were added; then 2-5 parts of chain extender were added, and the chain was extended at 20-30℃ for 30-50 minutes to obtain an aqueous polyurethane prepolymer. 5-15 parts of acrylic monomer and 1-2 parts of metal ions were added to the system, and the mixture was reacted at 65-70℃ for 2-3 hours. Finally, the mixture was vigorously stirred with deionized water to obtain a bio-based modified aqueous polyurethane. The bio-based modified waterborne polyurethane prepared above is dispersed and stirred with 5-6 parts of coupling agent and 2-5 parts of photoinitiator to obtain a colloid. The colloid is placed in a vacuum degassing machine to degas, thereby obtaining a bio-based modified bipolar plate gas path sealing adhesive with high self-healing properties.

2. The bio-based modified highly self-healing bipolar plate gas path sealing adhesive according to claim 1, characterized in that, The polymer polyol is one or both of polyether polyol and polycarbonate polyol.

3. The bio-based modified highly self-healing bipolar plate gas path sealing adhesive according to claim 1, characterized in that, The bio-based polyol is one of the following: alcoholysis linseed oil polyol, castor oil polyol, palm oil-based polyol, and acetate corn starch polyol.

4. The bio-based modified highly self-healing bipolar plate gas path sealing adhesive according to claim 1, characterized in that, The chain extender is one or more of 2,2-dimethylolpropionic acid, 1,4-butanediol, ethylenediamine, and 2,2'-diaminodiphenyl disulfide.

5. The bio-based modified highly self-healing bipolar plate gas path sealing adhesive according to claim 1, characterized in that, The acrylic monomer is one of hydroxyethyl methacrylate, hydroxypropyl methacrylate, and pentaerythritol triacrylate.

6. The bio-based modified highly self-healing bipolar plate gas path sealing adhesive according to claim 1, characterized in that, The diisocyanate is isophorone diisocyanate; the catalyst is either stannous octoate or dibutyltin dilaurate; and the neutralizing agent is triethylamine.

7. The bio-based modified highly self-healing bipolar plate gas path sealing adhesive according to claim 1, characterized in that, The coupling agent is one of γ-aminopropyltriethoxysilane, thiol, and γ-glycidoxypropyltrimethoxysilane; the photoinitiator is one of 2-hydroxy-4-(2-hydroxyethoxy)-2-methylphenylacetone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, and diphenyl-(2,4,6-trimethylbenzoyl).

8. The application of a bio-based modified highly self-healing bipolar plate gas path sealing adhesive as described in any one of claims 1-7 in bipolar plate gas path sealing.

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