Modified epoxy resin, preparation method thereof and perovskite UV packaging adhesive composition containing modified epoxy resin

Abstract

The invention relates to the technical field of UV adhesive packaging, in particular to modified epoxy resin, a preparation method of the modified epoxy resin and a perovskite UV packaging adhesive composition containing the modified epoxy resin. The modified epoxy resin is synthesized by reacting the following resins and monomers, the molar ratio of the resin A to the monomer B is controlled to be (2.02-2.04): 1, the molar ratio of the monomer C to the resin A is controlled to be (1.96-1.98): 1, and the structure of the modified epoxy resin is shown in the specification. The invention also discloses a preparation method of the modified epoxy resin. By adding the synthesized modified epoxy resin and all the components in the perovskite UV packaging adhesive composition and regulating and controlling the proportion of all the components, on one hand, the compatibility and bonding problems of the UV adhesive and a perovskite material are solved, on the other hand, the moisture permeability of the UV adhesive is reduced, and the water and oxygen barrier capacity of the UV adhesive is enhanced. The preparation method provided by the invention is simple in operation process, raw materials are easy to purchase, and large-scale production and preparation can be carried out.

Description

Technical Field

[0001] The present invention relates to the technical field of UV adhesive packaging, and in particular to a modified epoxy resin, a preparation method thereof, and a perovskite UV packaging adhesive composition containing the modified epoxy resin. Background Art

[0002] Perovskite solar cells (PSCs) have become a research hotspot for the next generation of photovoltaic technology due to their excellent photoelectric conversion efficiency (laboratory-certified efficiency >26%), solution processability, low-cost manufacturing potential, and flexibility. However, perovskite materials are extremely sensitive to moisture, oxygen, and ultraviolet light. They are prone to decomposition, ion migration, and phase separation under environmental conditions such as humidity, heat, and sunlight, resulting in rapid degradation of device performance and severely restricting their commercial application.

[0003] Perovskite materials are prone to thermal degradation above 85°C, while traditional packaging materials such as EVA (ethylene-vinyl acetate copolymer) or POE (polyolefin elastomer) require high-temperature lamination process (>120°C) for curing, which can easily damage the perovskite active layer. In contrast, UV adhesive systems can be quickly cured at room temperature and have strong process compatibility. However, UV adhesives have the following problems as perovskite packaging materials: 1. UV adhesives applied to perovskite materials can easily cause corrosion of the perovskite material and are difficult to be compatible; 2. Ordinary UV adhesives have limited water and oxygen barrier capabilities (water vapor transmission rate WVTR is 10-50g / (m 2 ·day); 3. The surface energy of perovskite is low, and ordinary UV adhesives are difficult to produce good adhesion.

[0004] Therefore, there is an urgent need to provide a new perovskite UV encapsulation adhesive composition and a preparation method thereof to solve the above problems. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a modified epoxy resin, a preparation method thereof, and a perovskite UV encapsulation adhesive composition containing the same. By adding the synthesized modified epoxy resin and the components in the perovskite UV encapsulation adhesive composition and regulating the proportions of the components, on the one hand, the compatibility and bonding problems between the UV adhesive and the perovskite material are solved, and on the other hand, the water vapor permeability of the UV adhesive is reduced, thereby enhancing its water and oxygen barrier capability.

[0006] In order to solve the above technical problems, the first technical solution adopted by the present invention is to provide a modified epoxy resin, the structural formula of which is shown below:

[0007]

[0008] Among them, R1 is n is 2 to 4; R2 is H or methyl, and the structure of R3 is as follows:

[0009]

[0010] The second technical solution adopted by the present invention is to provide a method for preparing the modified epoxy resin as described above, comprising the following steps:

[0011] Step 1: Heat resin A, add monomer B and catalyst I in four equal portions, and control the temperature at 135-150° C. to obtain a first reaction solution;

[0012] Step 2: heating the first reaction solution to 150-160° C., keeping the temperature for reaction, and taking a sample to measure the acid value until the acid value reaches 0 to obtain a second reaction solution;

[0013] Step 3: Cool the second reaction liquid to 95-105° C., introduce a nitrogen and oxygen mixed gas, add 25% of the total mass of monomer C and polymerization inhibitor D, and heat again to 110-120° C. to obtain a third reaction liquid;

[0014] Step 4: Add catalyst II to the third reaction solution, and slowly dropwise add the remaining monomer C. During this stage, the temperature is controlled at 115-125° C. to obtain a fourth reaction solution.

[0015] Step 5: heat the fourth reaction solution to 125-135° C., keep the temperature for reaction, take samples to measure the acid value until the acid value is 0, cool to 75-85° C., add inhibitor E and mix well, and cool to room temperature to obtain the modified epoxy resin.

[0016] In a preferred embodiment of the present invention, the structural formula of the resin A is as follows:

[0017]

[0018] In a preferred embodiment of the present invention, the structural formula of the monomer B is as follows:

[0019] HOOC—R1—COOH

[0020] Among them, R1 is n is 2 to 4.

[0021] In a preferred embodiment of the present invention, the structural formula of the monomer C is as follows:

[0022]

[0023] Wherein, R2 is H or methyl.

[0024] In a preferred embodiment of the present invention, the molar ratio of the resin A to the monomer B is (2.02-2.04):1.

[0025] In a preferred embodiment of the present invention, the molar ratio of the monomer C to the resin A is (1.96-1.98):1.

[0026] In a preferred embodiment of the present invention, the polymerization inhibitor D is methylhydroquinone, and the added amount is 0.1% of the total mass of the resin A, monomer B and monomer C; the polymerization inhibitor E is a mixture of p-hydroxyanisole and 2-tert-butylhydroquinone, the mixing mass ratio is 1, and the added amount is 0.2% of the total mass of the resin A, monomer B and monomer C.

[0027] In a preferred embodiment of the present invention, the catalyst I and catalyst II are both triphenylphosphine, wherein the addition amount of catalyst I is 0.2% of the total mass of resin A and monomer B, and the addition amount of catalyst II is 0.1% of the total mass of resin A, monomer B and monomer C.

[0028] To solve the above technical problems, the third technical solution adopted by the present invention is to provide a perovskite UV encapsulant composition, comprising the modified epoxy resin as described above, and comprising the following components by weight:

[0029]

[0030] In a preferred embodiment of the present invention, the difunctional aliphatic polyurethane acrylate is selected from one of Sartomer CN9014NS, Sartomer CN310NS, and Changxing DR-U396; the monofunctional UV monomer is at least one of isobornyl acrylate (IBOA), isobornyl methacrylate (IBOMA), and Youyang AM-319; and the multifunctional UV monomer is one of trimethylolpropane triacrylate (TMPTA) and dipentaerythritol hexaacrylate (DPHA).

[0031] In a preferred embodiment of the present invention, the photoinitiator is at least one of photoinitiator 1173, photoinitiator TMO, and Qingdao Jidejia photoinitiator 907T; the auxiliary agent is one of BYK-1794 and BYK-1799.

[0032] The preparation method of the perovskite UV encapsulant composition comprises the following steps: uniformly mixing raw material components including the modified epoxy resin, the difunctional aliphatic polyurethane acrylate, the monofunctional UV monomer, the multifunctional UV monomer, the photoinitiator, and the auxiliary agent to obtain the perovskite UV encapsulant composition.

[0033] The beneficial effects of the present invention are:

[0034] (1) The present invention provides a modified epoxy resin, the double bonds at both ends of the molecular chain are extremely active and can be quickly cured under UV irradiation. During the synthesis reaction, chain extension and end-capping both ensure the complete reaction of the carboxyl group, so that the resin has good compatibility with the perovskite material; the hydrophobic flexible chain segments introduced by chain extension enhance the adhesion performance of the system. In addition, the introduction of the naphthalene ring structure reduces the water vapor permeability of the resin system and enhances its water and oxygen barrier ability. This is mainly due to: on the one hand, the highly non-polar nature of the naphthalene ring structure makes it extremely poorly compatible with water molecules, and its strong hydrophobicity makes it difficult for water molecules to wet and adsorb; on the other hand, the planar rigid structure of the naphthalene ring makes the molecular chains more tightly arranged, forming a highly dense cross-linked network after curing, which is difficult for water to penetrate and diffuse.

[0035] (2) The present invention provides a perovskite UV encapsulant composition comprising, in addition to the modified epoxy resin described above, a difunctional aliphatic urethane acrylate, a monofunctional UV monomer, a polyfunctional UV monomer, a photoinitiator, and an additive, all of which are compatible with perovskite materials. The difunctional aliphatic urethane acrylate has a low water vapor permeability and exhibits good adhesion to the perovskite material.

[0036] (3) In summary, the present invention solves the compatibility and bonding problems between UV adhesives and perovskite materials on the one hand, and reduces the water vapor permeability of UV adhesives on the other hand, thereby enhancing their water and oxygen barrier capabilities.

[0037] (4) The preparation method provided by the present invention has a simple operation process and the raw materials are easy to purchase, and can be produced and prepared on a large scale. DETAILED DESCRIPTION

[0038] The preferred embodiments of the present invention are described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0039] The embodiments of the present invention include:

[0040] Example 1

[0041] Preparation method of modified epoxy resin in this embodiment:

[0042] Add 329.7g of Resin A to a 1L four-necked flask (or kettle) equipped with a mechanical stirrer. N2 was introduced, and the mixture was heated in an oil bath set to 135°C. Once the stirrer could be manually rotated smoothly, the stirrer was turned on. When the temperature in the flask (or kettle) reached 135°C, 70.8g of Monomer B (succinic acid) and 0.80g of triphenylphosphine were added in four equal portions, maintaining a molar ratio of Resin A to Monomer B (succinic acid) of 2.02:1. As this reaction is exothermic, the temperature in the flask (or kettle) should be maintained between 135-140°C. After the addition of Monomer B (succinic acid) and triphenylphosphine, the oil bath was set to 150°C. Once the temperature in the flask (or kettle) reached 150°C, the reaction was maintained. Samples were taken and the acid value was measured until the acid value was essentially zero, indicating the reaction was complete.

[0043] Remove the four-necked flask (kettle) from the oil bath and allow it to cool naturally in air. Then, weigh 171.1 g of Monomer C (acrylic acid), maintaining a molar ratio of 1.96:1 between Monomer C (acrylic acid) and Resin A. Once the temperature in the four-necked flask (kettle) has dropped to 100°C, place the flask in a preheated oil bath at 100°C. A nitrogen and oxygen mixture (at a flow rate ratio of 1) is introduced. Add 42.8 g (25% of the total mass of Monomer C (acrylic acid)) and 0.57 g of methylhydroquinone. Set the oil bath temperature to 115°C. Then add the remaining 128.3g of monomer C (acrylic acid) to the constant pressure dropping funnel. When the temperature in the four-necked flask (kettle) rises to 115°C, add 0.57g of triphenylphosphine. Then slowly open the valve of the constant pressure dropping funnel and allow monomer C (acrylic acid) to slowly drip into the four-necked flask (kettle). Since this reaction is exothermic, it is necessary to control the temperature in the four-necked flask (kettle) to be 115-120°C. After the monomer C (acrylic acid) has been dripped, the oil bath temperature is set to 125°C. When the temperature in the four-necked flask (kettle) rises to 125°C, keep the reaction warm, take samples to measure the acid value until the acid value is substantially 0, the reaction is completed, and the heating is turned off. The four-necked flask (kettle) was removed from the oil bath and naturally cooled in the air. When the temperature in the four-necked flask (kettle) dropped to 75°C, 1.14 g of a mixture of p-hydroxyanisole and 2-tert-butylhydroquinone was added in a mixing ratio of 1. After stirring evenly, the product was poured into a 1 L wide-mouth plastic jar and naturally cooled to room temperature in the air to obtain the final product, modified epoxy resin, which was recorded as modified epoxy resin 1.

[0044] Preparation method of the perovskite UV encapsulation adhesive composition of this embodiment:

[0045] The raw material components including modified epoxy resin, difunctional aliphatic polyurethane acrylate, monofunctional UV monomer, multifunctional UV monomer, photoinitiator and auxiliary agent are fully mixed to obtain a perovskite UV encapsulation adhesive composition.

[0046] The components (by mass fraction) of the perovskite UV encapsulant of compositions 1-3 are shown in Table 1.

[0047] Table 1

[0048]

[0049] Example 2

[0050] Preparation method of modified epoxy resin in this embodiment:

[0051] To a 1L four-necked flask (or kettle) equipped with a mechanical stirrer, add 332.9g of Resin A, flow nitrogen, and heat in an oil bath set to 135°C. Once the stirrer can be manually rotated smoothly, turn it on. When the temperature in the flask (or kettle) reaches 135°C, add 79.2g of Monomer B (glutaric acid) and 0.82g of triphenylphosphine in four equal portions, maintaining a molar ratio of Resin A to Monomer B (glutaric acid) of 2.04:1. As this reaction is exothermic, maintain the temperature in the flask (or kettle) between 140-145°C. After the addition of Monomer B (glutaric acid) and triphenylphosphine, set the oil bath to 155°C. Once the temperature in the flask (or kettle) reaches 155°C, maintain the reaction. Samples are taken for acid determination until the acid value is essentially zero, marking the end of the reaction.

[0052] Remove the four-necked flask (kettle) from the oil bath and allow it to cool naturally in air. Then, weigh 208.5g of Monomer C (methacrylic acid), maintaining a molar ratio of Monomer C (methacrylic acid) to Resin A of 1.98:1. Once the temperature in the four-necked flask (kettle) has dropped to 100°C, place the flask in a preheated oil bath at 100°C. A nitrogen and oxygen mixture (flow ratio of 1) is introduced. Add 52.1g (25% of the total mass of Monomer C (methacrylic acid)) and 0.62g of methylhydroquinone. Set the oil bath temperature to 115°C. Then, the remaining 156.4 g of monomer C (methacrylic acid) was added to the constant pressure dropping funnel. When the temperature in the four-necked flask (kettle) rose to 115°C, 0.62 g of triphenylphosphine was added. The valve of the constant pressure dropping funnel was then slowly opened to allow monomer C (methacrylic acid) to slowly drip into the four-necked flask (kettle). Since the reaction is exothermic, the temperature in the four-necked flask (kettle) needs to be controlled at 120-125°C. After the monomer C (methacrylic acid) has been dripped, the oil bath temperature is set to 130°C. When the temperature in the four-necked flask (kettle) rises to 130°C, the reaction is kept warm and samples are taken to measure the acid value until the acid value is substantially 0. The reaction is then terminated and the heating is turned off. The four-necked flask (kettle) was removed from the oil bath and naturally cooled in the air. When the temperature in the four-necked flask (kettle) dropped to 85°C, 1.24g of a mixture of p-hydroxyanisole and 2-tert-butylhydroquinone was added in a mixing ratio of 1. After stirring evenly, the product was poured into a 1L wide-mouth plastic jar and naturally cooled to room temperature in the air to obtain the final product, modified epoxy resin, which was recorded as modified epoxy resin 2.

[0053] The preparation method of the perovskite UV encapsulation adhesive composition in this embodiment is the same as the preparation method of the perovskite UV encapsulation adhesive composition in Example 1, and will not be described in detail here.

[0054] The components (by mass fraction) of the perovskite UV encapsulant of compositions 4-6 are shown in Table 2.

[0055] Table 2

[0056]

[0057]

[0058] Example 3

[0059] Preparation method of modified epoxy resin in this embodiment:

[0060] To a 1L four-necked flask (or kettle) equipped with a mechanical stirrer, add 331.3g of Resin A, flow nitrogen, and heat in an oil bath set to 135°C. Once the stirrer can be manually rotated smoothly, turn it on. When the temperature in the flask (or kettle) reaches 135°C, add 87.6g of Monomer B (adipic acid) and 0.84g of triphenylphosphine in four equal portions, maintaining a molar ratio of Resin A to Monomer B (adipic acid) of 2.03:1. As this reaction is exothermic, maintain the temperature in the flask (or kettle) at 145-150°C. After Monomer B (adipic acid) and triphenylphosphine are added, set the oil bath to 160°C. Once the temperature in the flask (or kettle) reaches 160°C, maintain the reaction. Samples are taken and measured for acid value until the acid value is essentially zero, marking the end of the reaction.

[0061] Remove the four-necked flask (kettle) from the oil bath and allow it to cool naturally in air. Then, weigh 206.3g of Monomer C (methacrylic acid), maintaining a molar ratio of Monomer C (methacrylic acid) to Resin A of 1.97:1. Once the temperature in the four-necked flask (kettle) has dropped to 100°C, place the flask in a preheated oil bath at 100°C. A nitrogen and oxygen mixture (flow ratio of 1) is introduced. Add 51.6g (25% of the total mass of Monomer C (methacrylic acid)) and 0.63g of methylhydroquinone. Set the oil bath temperature to 115°C. Then, the remaining 154.7 g of monomer C (methacrylic acid) was added to the constant pressure dropping funnel. When the temperature in the four-necked flask (kettle) rose to 115°C, 0.63 g of triphenylphosphine was added. The valve of the constant pressure dropping funnel was then slowly opened to allow monomer C (methacrylic acid) to slowly drip into the four-necked flask (kettle). Since the reaction is exothermic, the temperature in the four-necked flask (kettle) needs to be controlled at 120-125°C. After the monomer C (methacrylic acid) has been dripped, the oil bath temperature is set to 135°C. When the temperature in the four-necked flask (kettle) rises to 135°C, the reaction is kept warm and samples are taken to measure the acid value until the acid value is substantially 0. The reaction is then terminated and the heating is turned off. The four-necked flask (kettle) was removed from the oil bath and naturally cooled in the air. When the temperature in the four-necked flask (kettle) dropped to 80°C, 1.25g of a mixture of p-hydroxyanisole and 2-tert-butylhydroquinone was added in a mixing ratio of 1. After stirring evenly, the product was poured into a 1L wide-mouth plastic jar and naturally cooled to room temperature in the air to obtain the final product, modified epoxy resin, which was recorded as modified epoxy resin 3.

[0062] The preparation method of the perovskite UV encapsulation adhesive composition in this embodiment is the same as the preparation method of the perovskite UV encapsulation adhesive composition in Example 1, and will not be described in detail here.

[0063] The components (by mass fraction) of the perovskite UV encapsulant of compositions 7-9 are shown in Table 3.

[0064] Table 3

[0065]

[0066] The evaluation criteria for each item of the perovskite UV encapsulant composition are shown in Table 4.

[0067] Table 4

[0068]

[0069] The test results of each item of each perovskite UV encapsulant composition are shown in Table 5.

[0070] Table 5

[0071]

[0072]

[0073] Note: ○ represents compliance with regulations, and × represents non-compliance with regulations

[0074] Compositions 1, 4, and 7 all contain more difunctional aliphatic urethane acrylic resin and less modified epoxy resin than compositions 3, 6, and 9, respectively. While polyurethane resins offer greater flexibility, their structure dictates a higher water vapor permeability than modified epoxy resins with naphthalene ring structures. Consequently, the shear force of the system increases, i.e., the bond strength is enhanced, but the water vapor permeability is high. Compositions 2, 5, and 8 all contain less difunctional aliphatic urethane acrylic resin and more modified epoxy resin than compositions 3, 6, and 9, respectively. This results in a lower water vapor permeability and enhanced water and oxygen barrier properties, but a lower shear force, i.e., a weakened bond strength.

[0075] Comparative Example 1

[0076] The preparation method of the modified epoxy resin in this comparative example is different from that in Example 3 in that the molar ratio of resin A to monomer B (adipic acid) is 2.01:1, and the molar ratio of monomer C (methacrylic acid) to resin A is 1.99:1. The specific preparation method is as follows:

[0077] To a 1L four-necked flask (or kettle) equipped with a mechanical stirrer, add 328.0g of Resin A, flow nitrogen, and heat in an oil bath set to 135°C. Once the stirrer can be manually rotated smoothly, turn it on. When the temperature in the flask (or kettle) reaches 135°C, add 87.6g of Monomer B (adipic acid) and 0.83g of triphenylphosphine in four equal portions, maintaining a molar ratio of Resin A to Monomer B (adipic acid) of 2.01:1. As this reaction is exothermic, maintain the temperature in the flask (or kettle) at 145-150°C. After Monomer B (adipic acid) and triphenylphosphine are added, set the oil bath to 160°C. Once the temperature in the flask (or kettle) reaches 160°C, maintain the reaction. Samples are taken and the acid value is measured until the acid value remains essentially constant, marking the end of the reaction.

[0078] Remove the four-necked flask (kettle) from the oil bath and allow it to cool naturally in air. Then, weigh 206.4g of Monomer C (methacrylic acid), maintaining a molar ratio of Monomer C (methacrylic acid) to Resin A of 1.99:1. Once the temperature in the four-necked flask (kettle) has dropped to 100°C, place the flask in a preheated oil bath at 100°C. A nitrogen and oxygen mixture (flow ratio of 1) is introduced. Add 51.6g (25% of the total mass of Monomer C (methacrylic acid)) and 0.62g of methylhydroquinone. Set the oil bath temperature to 115°C. Then, the remaining 154.8 g of monomer C (methacrylic acid) was added to the constant pressure dropping funnel. When the temperature in the four-necked flask (kettle) rose to 115°C, 0.62 g of triphenylphosphine was added. The valve of the constant pressure dropping funnel was then slowly opened to allow monomer C (methacrylic acid) to slowly drip into the four-necked flask (kettle). Since the reaction is exothermic, the temperature in the four-necked flask (kettle) needs to be controlled at 120-125°C. After the monomer C (methacrylic acid) has been dripped, the oil bath temperature is set to 135°C. When the temperature in the four-necked flask (kettle) rises to 135°C, the reaction is kept warm. Samples are taken to measure the acid value until the acid value remains substantially unchanged. The reaction is then completed and the heating is turned off. The four-necked flask (kettle) was removed from the oil bath and naturally cooled in the air. When the temperature in the four-necked flask (kettle) dropped to 80°C, 1.24g of a mixture of p-hydroxyanisole and 2-tert-butylhydroquinone was added in a mixing ratio of 1. After stirring evenly, the product was poured into a 1L wide-mouth plastic jar and naturally cooled to room temperature in the air to obtain the final product, modified epoxy resin, which was recorded as modified epoxy resin 4.

[0079] Comparative Example 2

[0080] The preparation method of the modified epoxy resin in this comparative example differs from that in Example 3 in that the molar ratio of resin A to monomer B (adipic acid) is 2.05:1, and the molar ratio of monomer C (methacrylic acid) to resin A is 1.95:1. The specific preparation method is as follows:

[0081] Add 334.6g of Resin A to a 1L four-necked flask (or kettle) equipped with a mechanical stirrer. N2 was introduced, and the mixture was heated in an oil bath set to 135°C. Once the stirrer could be manually rotated smoothly, the stirrer was turned on. When the temperature in the flask (or kettle) reached 135°C, 87.6g of Monomer B (adipic acid) and 0.84g of triphenylphosphine were added in four equal portions, maintaining a molar ratio of Resin A to Monomer B (adipic acid) of 2.05:1. As this reaction is exothermic, the temperature in the flask (or kettle) should be maintained at 145-150°C. After the addition of Monomer B (adipic acid) and triphenylphosphine, the oil bath was set to 160°C. Once the temperature in the flask (or kettle) reached 160°C, the reaction was maintained. Samples were taken and the acid value was measured until the acid value was essentially zero, indicating the reaction was complete.

[0082] Remove the four-necked flask (kettle) from the oil bath and allow it to cool naturally in air. Then, weigh 206.3g of Monomer C (methacrylic acid), maintaining a molar ratio of Monomer C (methacrylic acid) to Resin A of 1.95:1. Once the temperature in the four-necked flask (kettle) has dropped to 100°C, place the flask in a preheated oil bath at 100°C. A nitrogen and oxygen mixture (flow ratio of 1) is introduced. Add 51.6g (25% of the total mass of Monomer C (methacrylic acid)) and 0.63g of methylhydroquinone. Set the oil bath temperature to 115°C. Then, the remaining 154.7 g of monomer C (methacrylic acid) was added to the constant pressure dropping funnel. When the temperature in the four-necked flask (kettle) rose to 115°C, 0.63 g of triphenylphosphine was added. The valve of the constant pressure dropping funnel was then slowly opened to allow monomer C (methacrylic acid) to slowly drip into the four-necked flask (kettle). Since the reaction is exothermic, the temperature in the four-necked flask (kettle) needs to be controlled at 120-125°C. After the monomer C (methacrylic acid) has been dripped, the oil bath temperature is set to 135°C. When the temperature in the four-necked flask (kettle) rises to 135°C, the reaction is kept warm and samples are taken to measure the acid value until the acid value is substantially 0. The reaction is then terminated and the heating is turned off. The four-necked flask (kettle) was removed from the oil bath and naturally cooled in the air. When the temperature in the four-necked flask (kettle) dropped to 80°C, 1.26g of a mixture of p-hydroxyanisole and 2-tert-butylhydroquinone was added in a mixing ratio of 1. After stirring evenly, the product was poured into a 1L wide-mouth plastic jar and naturally cooled to room temperature in the air to obtain the final product, modified epoxy resin, which was recorded as modified epoxy resin 5.

[0083] Comparative Example 3

[0084] The difference between the preparation method of the modified epoxy resin in this comparative example and that in Example 3 is that monomer B is pimelic acid, that is, R1 is When n is 5, the chain segments introduced by chain extension are short and have poor flexibility, which does not improve the adhesion performance of the system. Therefore, no comparison is made here. The structure of monomer B is as follows:

[0085] HOOC-R1-COOH

[0086] The specific preparation method is as follows:

[0087] Add 331.3g of Resin A to a 1L four-necked flask (or kettle) equipped with a mechanical stirrer. N2 is introduced, and the mixture is heated in an oil bath set to 135°C. Once the stirrer can be manually rotated smoothly, turn it on. When the temperature in the flask (or kettle) reaches 135°C, add 96.0g of Monomer B (pimelic acid) and 0.85g of triphenylphosphine in four equal portions, maintaining a molar ratio of Resin A to Monomer B (pimelic acid) of 2.03:1. As this reaction is exothermic, maintain the temperature in the flask (or kettle) at 145-150°C. After Monomer B (pimelic acid) and triphenylphosphine are added, set the oil bath to 160°C. Once the temperature in the flask (or kettle) reaches 160°C, maintain the reaction. Samples are taken for acid determination until the acid value is essentially zero, marking the end of the reaction.

[0088] Remove the four-necked flask (kettle) from the oil bath and allow it to cool naturally in air. Then, weigh 206.3g of Monomer C (methacrylic acid), maintaining a molar ratio of Monomer C (methacrylic acid) to Resin A of 1.97:1. Once the temperature in the four-necked flask (kettle) has dropped to 100°C, place the flask in a preheated oil bath at 100°C. A nitrogen and oxygen mixture (flow ratio of 1) is introduced. Add 51.6g (25% of the total mass of Monomer C (methacrylic acid)) and 0.63g of methylhydroquinone. Set the oil bath temperature to 115°C. Then, the remaining 154.7 g of monomer C (methacrylic acid) was added to the constant pressure dropping funnel. When the temperature in the four-necked flask (kettle) rose to 115°C, 0.63 g of triphenylphosphine was added. The valve of the constant pressure dropping funnel was then slowly opened to allow monomer C (methacrylic acid) to slowly drip into the four-necked flask (kettle). Since the reaction is exothermic, the temperature in the four-necked flask (kettle) needs to be controlled at 120-125°C. After the monomer C (methacrylic acid) has been dripped, the oil bath temperature is set to 135°C. When the temperature in the four-necked flask (kettle) rises to 135°C, the reaction is kept warm and samples are taken to measure the acid value until the acid value is substantially 0. The reaction is then terminated and the heating is turned off. The four-necked flask (kettle) was removed from the oil bath and naturally cooled in the air. When the temperature in the four-necked flask (kettle) dropped to 80°C, 1.27g of a mixture of p-hydroxyanisole and 2-tert-butylhydroquinone was added in a mixing ratio of 1. After stirring evenly, the product was poured into a 1L wide-mouth plastic jar and naturally cooled to room temperature in the air to obtain the final product, modified epoxy resin, which was recorded as modified epoxy resin 6.

[0089] The preparation methods of the perovskite UV encapsulant compositions of Comparative Examples 1, 2, and 3 are the same as those of the perovskite UV encapsulant composition in Example 3, except that different modified epoxy resins are used. The components of the perovskite UV encapsulant (by mass fraction) are shown in Table 6.

[0090] Table 6

[0091]

[0092] The test results of each item of each perovskite UV encapsulant composition are shown in Table 7.

[0093] Table 7

[0094]

[0095]

[0096] Note: ○ represents compliance with regulations, and × represents non-compliance with regulations

[0097] In composition 9, the modified epoxy resin 3 of Example 3 is used. Since the molar ratio of resin A to monomer B (adipic acid) is 2.03:1, and the molar ratio of monomer C (methacrylic acid) to resin A is 1.97:1, both chain extension and end-capping ensure complete reaction of the carboxyl groups, resulting in good compatibility between the resin and the perovskite material. Furthermore, the low residual epoxy groups ensure the system's cure rate, i.e., a certain crosslinking density, and thus the system's water vapor permeability. The adipic acid chain segments used in the chain extension are of appropriate length, improving resin flexibility and adhesion while also having a minimal impact on water vapor permeability. Combined with the formulation, all performance characteristics of composition 9 meet the requirements.

[0098] In composition 10, the modified epoxy resin 4 of comparative example 1 is used. Since the molar ratio of resin A to monomer B (adipic acid) is 2.01:1, and the molar ratio of monomer C (methacrylic acid) to resin A is 1.99:1, both are close to the theoretical molar ratio. However, in the actual reaction process, at the theoretical molar ratio or close to the theoretical molar ratio, adipic acid or methacrylic acid cannot be completely reacted, and the residual acid in the composition will corrode the perovskite material and is incompatible with the perovskite material.

[0099] In composition 11, the modified epoxy resin 5 of comparative example 2 is used. Since the molar ratio of resin A to monomer B (adipic acid) is 2.05:1, and the molar ratio of monomer C (methacrylic acid) to resin A is 1.95:1, although the chain extension and end capping ensure the complete reaction of the carboxyl group, so that the resin has good compatibility with the perovskite material, there are still many residual epoxy groups, which reduces the curing rate of the system, affects the cross-linking density, and further affects the water vapor permeability of the system, making the water vapor permeability unqualified.

[0100] In composition 12, the modified epoxy resin 6 of comparative example 3 is used, the molar ratio of resin A to monomer B (pimelic acid) is 2.03:1, and the molar ratio of monomer C (methacrylic acid) to resin A is 1.97:1. Since monomer B is pimelic acid, the chain segment length is longer, which improves the flexibility of the resin and enhances the adhesion while also having a greater impact on the water vapor permeability, resulting in unqualified water vapor permeability.

[0101] Composition 13 did not include a modified epoxy resin. While polyurethane resins offer excellent flexibility, their structure dictates that their water vapor permeability is higher than that of modified epoxy resins with naphthalene ring structures. Therefore, without the addition of a modified epoxy resin, the system's water vapor permeability failed the standard.

[0102] This embodiment is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any other manner. Any person skilled in the art may utilize the above content as a guide to modify or modify the present invention into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications to the above embodiment that do not depart from the technical essence of the present invention are still within the scope of protection of the present invention.

Claims

1. A modified epoxy resin, characterized in that The structural formula is shown below: Among them, R1 is n is 2 to 4; R2 is H or methyl, and the structure of R3 is as follows:

2. A method for preparing a modified epoxy resin according to claim 1, characterized in that: The following steps are involved: Step 1: Heat resin A, add monomer B and catalyst I in four equal portions, and control the temperature at 135-150° C. to obtain a first reaction solution; Step 2: heating the first reaction solution to 150-160° C., keeping the temperature for reaction, and taking a sample to measure the acid value until the acid value reaches 0 to obtain a second reaction solution; Step 3: Cool the second reaction liquid to 95-105° C., introduce a nitrogen and oxygen mixed gas, add 25% of the total mass of monomer C and polymerization inhibitor D, and heat again to 110-120° C. to obtain a third reaction liquid; Step 4: Add catalyst II to the third reaction solution, and slowly dropwise add the remaining monomer C. During this stage, the temperature is controlled at 115-125° C. to obtain a fourth reaction solution. Step 5: heat the fourth reaction solution to 125-135° C., keep the temperature for reaction, take samples to measure the acid value until the acid value is 0, cool to 75-85° C., add inhibitor E and mix well, and cool to room temperature to obtain the modified epoxy resin.

3. The method for preparing the modified epoxy resin according to claim 2, wherein The structural formula of the resin A is as follows:

4. The method for preparing the modified epoxy resin according to claim 2, wherein The structural formula of the monomer B is as follows: HOOC-R1-COOH Among them, R1 is n is 2 to 4.

5. The method for preparing the modified epoxy resin according to claim 2, wherein The structural formula of the monomer C is as follows: Wherein, R2 is H or methyl.

6. The method for preparing the modified epoxy resin according to claim 2, wherein The molar ratio of the resin A to the monomer B is (2.02-2.04):

1.

7. The method for preparing the modified epoxy resin according to claim 2, wherein The molar ratio of the monomer C to the resin A is (1.96-1.98):

1.

8. The method for preparing the modified epoxy resin according to claim 2, wherein The polymerization inhibitor D is methylhydroquinone, and the addition amount is 0.1% of the total mass of the resin A, monomer B and monomer C; the polymerization inhibitor E is a mixture of p-hydroxyanisole and 2-tert-butylhydroquinone, the mixing mass ratio is 1, and the addition amount is 0.2% of the total mass of the resin A, monomer B and monomer C; The catalyst I and catalyst II are both triphenylphosphine, wherein the addition amount of catalyst I is 0.2% of the total mass of resin A and monomer B, and the addition amount of catalyst II is 0.1% of the total mass of resin A, monomer B and monomer C.

9. A perovskite UV encapsulation adhesive composition, characterized in that: The modified epoxy resin according to claim 1 comprises the following components by weight:

10. The perovskite UV encapsulant composition according to claim 9, characterized in that: The difunctional aliphatic polyurethane acrylate is selected from one of Sartomer CN9014NS, Sartomer CN310NS, and Changxing DR-U396; the monofunctional UV monomer is at least one of isobornyl acrylate (IBOA), isobornyl methacrylate (IBOMA), and Youyang AM-319; and the multifunctional UV monomer is one of trimethylolpropane triacrylate (TMPTA) and dipentaerythritol hexaacrylate (DPHA).

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