Transparent light-heat curing acrylic ester modified epoxy resin as well as preparation method and application thereof

Abstract

The invention relates to transparent light-heat curing acrylate modified epoxy resin and a preparation method and application thereof, and the transparent light-heat curing acrylate modified epoxy resin comprises the following components: aliphatic polyurethane acrylate oligomer, acrylate monomer, styrene-maleic anhydride copolymer, adhesion promoter, amino resin, photoinitiator, hydrogenated epoxy resin A and hydrogenated epoxy resin B, the composition is prepared from a thixotropic agent, an anti-aging agent, a UV absorbent, a light stabilizer, a curing agent and an accelerant. The problems that the requirement for glass fibers is high, holes are prone to occurring inside and the like due to insufficient infiltration of pure acrylic ester are solved, and the light photovoltaic flexible assembly prepared from the epoxy resin is excellent in performance and has good market application prospects.

Description

A transparent photocurable thermocurable acrylate-modified epoxy resin, its preparation method and application Technical Field

[0001] This invention belongs to the field of lightweight photovoltaic module technology, and specifically relates to a transparent photo-thermal curable acrylate modified epoxy resin, its preparation method, and its application. Background Technology

[0002] Lightweight photovoltaic modules used in applications with limited load-bearing capacity, such as rooftops, typically require reinforced panels and backsheets. The reinforced panels must be transparent with a relative temperature index (RTI) > 115℃, and are usually made of epoxy resin or acrylic resin. Epoxy resins offer good heat resistance, but to improve heat resistance, bisphenol A polyether epoxy is often added to pure epoxy resins. This type of epoxy has poor UV resistance and is prone to yellowing when exposed to air and ultraviolet light. Acrylic esters have high resistance to yellowing, but their pure aliphatic chains result in lower performance at high temperatures, and because free radical curing is difficult to control, the resulting products are usually pre-cured, with a glass fiber basis weight typically < 200 g / m². 2 Therefore, its performance is only one-third that of epoxy resin. Alternatively, high molecular weight acrylates can be directly added to epoxy resin to create blended acrylate-modified epoxy prepolymers. However, the acrylates in the prepolymers produced by this method are difficult to impregnate into the fiberglass cloth, and the acrylates will precipitate out during the PCT (Pressure Accelerated Aging) life test.

[0003] Patent CN115466565B uses light-cured pre-polyacrylate and highly breathable fiberglass cloth, employing a two-step curing method to enhance the wettability of acrylic resin. The resulting product exhibits good UV resistance, but its heat resistance is low, with a Tg < 80℃. In the second thermosetting stage, a laminator is used for thermal initiation to achieve better wettability. In the first step of prepreg preparation, a large amount of diluent is used during light curing to ensure wettability; however, this diluent is prone to explosion during production, causing severe environmental pollution. The second thermosetting stage requires an additional processing step, involving multiple layers, making the process more difficult and hindering the removal of air bubbles.

[0004] In patent CN117106214A, a simple light-curing resin is used. In order to ensure the wettability, the requirements for glass fiber are relatively high. Glass fiber cloth that has been treated with coupling agent is required. Moreover, due to the limitation of molding pressure, the monomer content in its formula is relatively high, which will also produce environmental problems such as hazardous monomer volatiles.

[0005] In patent CN118206847A, a blend of UV-curable acrylate and epoxy resin is used. First, UV curing is employed to increase adhesion, followed by a second stage of thermosetting to form an interpenetrating network structure, thereby improving the light transmittance and physical properties of the transparent composite material. However, to ensure the blending of epoxy resin and acrylate during production, 8wt%~14wt% of a low-toxicity diluent is still required, placing high demands on environmental protection equipment, necessitating the use of a regenerative thermal oxidizer (RTO) to treat waste gas. Furthermore, to improve the compatibility of the acrylate's Tg point with the epoxy resin, bisphenol A epoxy acrylate resin is used in the formulation, significantly reducing the UV resistance of the acrylate resin. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a transparent photo-thermal curable acrylate modified epoxy resin, its preparation method and application, overcoming the problems of high requirements for glass fiber and easy occurrence of internal pores caused by insufficient impregnation of pure acrylate.

[0007] This invention provides a transparent photo-thermal curable acrylate-modified epoxy resin, comprising the following components by weight: 10-40 parts aliphatic polyurethane acrylate oligomer; 5-10 parts acrylate monomer; 2-5 parts styrene-maleic anhydride copolymer; 1-5 parts adhesion promoter; 2-6 parts amino resin; 0.5-1.5 parts photoinitiator; 30-40 parts hydrogenated epoxy resin A; 10-20 parts hydrogenated epoxy resin B; 0.5-1.5 parts thixotropic agent; 0.5-1 part anti-aging agent; 2-3 parts UV absorber; 0.5-1 part light stabilizer; 2-3 parts curing agent; and 1-2 parts accelerator. The epoxy equivalent of hydrogenated epoxy resin A is 500-750 g / eq, and the epoxy equivalent of hydrogenated epoxy resin B is 200-300 g / eq.

[0008] Preferably, the acrylate monomer includes one or more of isobornyl methacrylate, tricyclodecanediethanol diacrylate, and tricyclodecanediethanol dimethacrylate.

[0009] Preferably, the weight-average molecular weight of the styrene-maleic anhydride copolymer is between Mw=4000 and 15000, wherein the molar ratio of styrene to maleic anhydride is 2-4:1.

[0010] Preferably, the adhesion promoter is an acrylic resin containing tripropylene glycol diacrylate (TPGDA), with the TPGDA content between 20 wt% and 40 wt%.

[0011] Preferably, the amino resin is a melamine-formaldehyde resin etherified with n-butanol.

[0012] Preferably, the photoinitiator is one or more of benzoin and its derivatives, benzoyl and its derivatives, acetophenone derivatives, and α-hydroxy ketone derivatives.

[0013] Preferably, the thixotropic agent is fumed silica.

[0014] Preferably, the anti-aging agent is one or more of hindered phenolic anti-aging agents 1076, 1098, and 1010.

[0015] Preferably, the UV absorber is one or more of the triazine UV absorbers UV1164, UV1577, and UV400.

[0016] Preferably, the light stabilizer is one or more of benzotriazole light stabilizers UV1130 and UV928.

[0017] Preferably, the curing agent is an acylhydrazine-based curing agent, such as sebacate hydrazine curing agent, adipate hydrazine curing agent, etc.

[0018] Preferably, the accelerator is an organic urea accelerator or a boronamine complex accelerator, more preferably an organic urea accelerator.

[0019] The present invention also provides a method for preparing transparent photo-thermal curable acrylate modified epoxy resin, comprising the following steps: (1) placing aliphatic polyurethane acrylate oligomer, acrylate monomer, styrene-maleic anhydride copolymer, adhesion promoter, amino resin, photoinitiator, hydrogenated epoxy resin A, hydrogenated epoxy resin B, thixotropic agent, anti-aging agent, UV absorber, and light stabilizer into a planetary stirring vessel according to the formula ratio, heating to 60-80℃, stirring for 20-30 minutes, and evacuating the vacuum, with the vacuum degree controlled at >0.8 bar, and then keeping warm at 60-80℃ after stirring; (2) grinding the curing agent and accelerator according to the formula ratio, and then adding them to the product of step (1) and stirring to obtain transparent photo-thermal curable acrylate modified epoxy resin.

[0020] The present invention also provides an application of a transparent photo-thermal curable acrylate-modified epoxy resin in lightweight photovoltaic flexible modules.

[0021] Beneficial Effects (1) The formulation of this invention does not use reactive diluents. Instead, it uses aliphatic polyurethane acrylate oligomers and traditional hydrogenated epoxy resins for high-temperature vacuum blending to achieve a homogeneous resin mixture. The viscosity of aliphatic polyurethane acrylate oligomers and hydrogenated epoxy resins is similar at 30°C. At 60-80°C, the viscosity of uncured aliphatic polyurethane acrylate oligomers is 1 / 4 to 1 / 10 of that of hydrogenated epoxy resins. During the composite process, the temperature of the reaction system increases, causing the low-viscosity aliphatic polyurethane acrylate oligomers to preferentially wet the glass fibers. UV irradiation crosslinks the aliphatic polyurethane acrylate oligomers to form a prepreg. The finished prepreg can be directly used for component encapsulation. The hydrogenated epoxy resin further wets and degasses the glass fibers to obtain a transparent photo-thermal curable acrylate-modified epoxy resin with low porosity.

[0022] (2) The present invention uses hydrogenated epoxy resin as epoxy resin base material. In order to solve the problem of low heat resistance of epoxy without bisphenol A and improve the overall heat resistance, styrene-maleic anhydride copolymer is used as epoxy resin hardener to improve the heat resistance of the system, increase the Tg point, reduce the phase separation between resin and fiber due to high temperature and high humidity during PCT test, and improve the overall relative temperature index RTI value of the material. At the same time, the epoxy groups of SMA can also improve the crosslinking degree of the system.

[0023] (3) High adhesion: The amino resin uses n-butanol etherified melamine formaldehyde resin, which has good compatibility with epoxy resin. The hydrophobic butoxy group can reduce the water absorption rate of the resin and improve the moisture and heat resistance of the material.

[0024] (4) The curing agent of the present invention simultaneously heat-cures hydrogenated epoxy resin with etherified amino resin, overcoming the disadvantages of low activity and slow curing of hydrogenated epoxy resin. It connects the acrylate end -OH with the hydrogenated epoxy resin end hydroxyl at 120~160℃ to achieve a higher degree of crosslinking.

[0025] (5) In the amino resin of the present invention, -NH2 and -NH- can accelerate the reaction rate of hydrogenated epoxy resin and curing agent under the catalysis of dicyandiamide, thus overcoming the problem of low reactivity of hydrogenated epoxy resin.

[0026] (6) The present invention synthesizes flexible aliphatic polyurethane acrylate to toughen hydrogenated epoxy resin, thereby solving the problem of low crosslinking degree and brittleness of hydrogenated epoxy resin. Detailed Implementation

[0027] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0028] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0029] A method for preparing aliphatic polyurethane acrylate oligomers includes the following steps: 0.5 mol of 1,6-hexanediol polycarbonate is added to a three-necked flask, followed by 1 mol of dehydrated TDI, 0.05% of p-methoxyphenol (total mass of raw materials), and 0.1% of dibutyltin dilaurate (total mass of raw materials). The mixture is reacted in N2 at 60°C for 3 hours. Then, 1 mol of HEA and hydroquinone polymerization inhibitor (0.1% by mass of HEA) are added, and the temperature is raised to 70-80°C. The reaction proceeds until -NCO approaches zero, yielding the aliphatic polyurethane acrylate oligomer.

[0030] The preparation method of transparent light- and heat-curing acrylate modified epoxy resin includes the following steps: (1) Aliphatic polyurethane acrylate oligomer, acrylate monomer, styrene-maleic anhydride copolymer, adhesion promoter, amino resin, photoinitiator, hydrogenated epoxy resin A, hydrogenated epoxy resin B, thixotropic agent, anti-aging agent, UV absorber and light stabilizer are placed into a planetary stirring vessel according to the formula ratio, heated to 60°C, stirred for 20-30 min, and vacuumed, with the vacuum degree controlled at >0.8 bar. After stirring, the mixture is kept at 60°C; (2) Curing agent and accelerator are ground according to the formula ratio and then added to the product of step (1) and stirred to obtain transparent light- and heat-curing acrylate modified epoxy resin.

[0031] Table 1 Formulation of transparent, thermosetting acrylate-modified epoxy resin (parts by weight) Table 2 Formulation of transparent gloss-thermosetting acrylate-modified epoxy resin (parts by weight) Table 3 Formulation of transparent gloss-thermosetting acrylate-modified epoxy resin (parts by weight) The application method of transparent light-heat curing acrylate modified epoxy resin includes the following steps: (1) using a coating machine to apply the resin to the release paper in reverse coating, with a resin basis weight of 54~68g / m 2 (2) Using a laminating machine, the unwinding weight is 160 g / m². 2 ~250g / m 2 Twill-woven fiberglass cloth is used to prepare the prepreg using a two-coating, one-impregnation process, with a lamination temperature of 60-70℃. After lamination, a film is applied, and then an LED at 365nm (1-3kW / cm²) is used. 2Irradiation intensity, photocuring crosslinked prepreg, forming a semi-prepreg photo-thermal curing acrylate modified epoxy resin prepreg; (3) Simulate lightweight flexible component packaging conditions, vacuum-curing the prepreg at 150℃ / 20min, and testing its physical properties and other reliability properties after thermal curing.

[0032] Table 4 Test Results Table 5 Test Results Table 6 Test Results 1. Comparison of Comparative Example 1 and Example 1 shows that polyurethane acrylate oligomers can significantly improve the weather resistance of materials.

[0033] 2. Examples 2 and 3 and Comparative Example 2 show that SMA can increase the glass transition temperature, increase the material Tg, and improve the high temperature resistance.

[0034] 3. Examples 4, 5, and Comparative Example 3 demonstrate that amino resins can increase the degree of crosslinking, improve the weather resistance of materials, and enhance the physical properties of materials.

[0035] 4. Comparing Comparative Example 4 with Examples 6 and 7 shows that even without an organic urea accelerator, the -NH- in the amino resin can catalyze the curing of dicyandiamide, but the curing rate will be lower.

Claims

1. A transparent photocurable / thermocurable acrylate-modified epoxy resin, characterized in that: The product comprises, by weight parts, the following components: 10-40 parts aliphatic polyurethane acrylate oligomer; 5-10 parts acrylate monomer; 2-5 parts styrene-maleic anhydride copolymer; 1-5 parts adhesion promoter; 2-6 parts amino resin; 0.5-1.5 parts photoinitiator; 30-40 parts hydrogenated epoxy resin A; 10-20 parts hydrogenated epoxy resin B; 0.5-1.5 parts thixotropic agent; 0.5-1 part anti-aging agent; 2-3 parts UV absorber; 0.5-1 part light stabilizer; 2-3 parts curing agent; and 1-2 parts accelerator. The epoxy equivalent of hydrogenated epoxy resin A is 500-750 g / eq, and the epoxy equivalent of hydrogenated epoxy resin B is 200-300 g / eq.

2. The transparent photocurable / thermocurable acrylate-modified epoxy resin according to claim 1, characterized in that: The acrylate monomers include one or more of isobornyl methacrylate, tricyclodecanediethanol diacrylate, and tricyclodecanediethanol dimethacrylate.

3. The transparent photocurable / thermocurable acrylate-modified epoxy resin according to claim 1, characterized in that: The weight-average molecular weight of the styrene-maleic anhydride copolymer is between Mw=4000 and 15000, wherein the molar ratio of styrene to maleic anhydride is 2-4:

1.

4. The transparent photocurable / thermocurable acrylate-modified epoxy resin according to claim 1, characterized in that: The adhesion promoter is an acrylic resin containing tripropylene glycol diacrylate.

5. The transparent photocurable / thermocurable acrylate-modified epoxy resin according to claim 1, characterized in that: The photoinitiator is one or more of benzoin and its derivatives, benzoyl and its derivatives, acetophenone derivatives, and α-hydroxy ketone derivatives.

6. The transparent photocurable / thermocurable acrylate-modified epoxy resin according to claim 1, characterized in that: The thixotropic agent is fumed silica; the anti-aging agent is one or more of hindered phenolic anti-aging agents 1076, 1098, and 1010; the UV absorber is one or more of triazine UV absorbers UV1164, UV1577, and UV400; and the light stabilizer is one or more of benzotriazole light stabilizers UV1130 and UV928.

7. The transparent photocurable / thermocurable acrylate-modified epoxy resin according to claim 1, characterized in that: The curing agent is an acylhydrazine-based curing agent; the accelerator is an organic urea accelerator or a boronamine complex accelerator.

8. A method for preparing a transparent photo-thermal curable acrylate modified epoxy resin as described in any one of claims 1-7, comprising the following steps: (1) placing aliphatic polyurethane acrylate oligomer, acrylate monomer, styrene-maleic anhydride copolymer, adhesion promoter, amino resin, photoinitiator, hydrogenated epoxy resin A, hydrogenated epoxy resin B, thixotropic agent, anti-aging agent, UV absorber, and light stabilizer into a planetary mixing vessel according to the formulation ratio, heating to 60-80°C, stirring for 20-30 minutes, and evacuating the vessel, with the vacuum degree controlled at >0.8 bar, and then keeping the vessel at 60-80°C after stirring; (2) grinding the curing agent and accelerator according to the formulation ratio, and then adding them to the product of step (1) and stirring to obtain a transparent photo-thermal curable acrylate modified epoxy resin.

9. The application of a transparent photo-thermal curable acrylate-modified epoxy resin as described in any one of claims 1-7 in lightweight photovoltaic flexible modules.

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