High-strength and high-toughness salt-fog-resistant epoxy structural adhesive, preparation method and application

Abstract

The application belongs to the technical field of epoxy adhesive preparation, and particularly relates to a high-strength and high-toughness salt mist-resistant epoxy structural adhesive, a preparation method and application, which comprises component A and component B, the weight ratio of component A and component B is 100:25-35; the component A comprises the following raw materials: bisphenol A epoxy resin, heterocyclic epoxy resin, multifunctional epoxy resin, diluent, toughening agent, fumed silica and filler; the component B comprises the following raw materials: polyether amine, isophorone diamine, low-molecular polyamide, fumed silica, filler and 2.4.6-tris(dimethylaminomethyl)phenol; the application can improve the strength, toughness and salt mist resistance of the epoxy structural adhesive.

Description

Technical Field

[0001] This invention belongs to the field of epoxy adhesive preparation technology, specifically relating to a high-strength, high-toughness, salt spray resistant epoxy structural adhesive, its preparation method, and its application. Background Technology

[0002] The main equipment for wind power generation is the wind turbine generator set, with the wind turbine blade being the core component. A wind turbine blade is generally composed of three parts bonded together: a cathode and anode semi-shells and a shear beam. The bonding material is epoxy structural adhesive, and the adhesive layer is subjected to shear forces and peel forces. Therefore, the epoxy structural adhesive used in wind turbine blades needs to have high mechanical strength, strong impact resistance, and excellent fatigue resistance.

[0003] With the development of the wind power industry, onshore wind power is gradually becoming saturated, and large-scale development is beginning in offshore wind power. Furthermore, wind turbine blades are becoming increasingly larger, requiring epoxy structural adhesives to not only achieve high strength and toughness but also long service life in harsh environments, such as corrosion resistance, salt spray resistance, electrical tracking resistance, and resistance to electric shock. However, traditional epoxy structural adhesives suffer from poor flexibility, high brittleness, high exothermic curing reaction, and short service life in harsh environments. Current research focuses on toughening epoxy structural adhesives and mitigating the rapid exothermic curing process, while research on the short service life under harsh conditions is limited. For example, patents CN102212322A and CN102277117B both use carbon nanotubes to toughen epoxy structural adhesives; CN102329586B uses hyperbranched polyester to improve the impact strength of epoxy structural adhesives and mitigates the rapid exothermic curing process by extending the operating time. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a high-strength, high-toughness, salt spray resistant epoxy structural adhesive, its preparation method and application, which can improve the strength, toughness and salt spray resistance of epoxy structural adhesive.

[0005] This invention provides a high-strength, high-toughness, salt spray resistant epoxy structural adhesive, comprising component A and component B, wherein the weight ratio of component A to component B is 100:25~35 (preferably 100:28). Component A comprises the following raw materials in parts by weight. 40-50 parts of bisphenol A epoxy resin. 20-30 parts of heterocyclic epoxy resin. 10-20 parts of multifunctional epoxy resin 1-10 parts of diluent 10-20 parts toughening agent 10-15 parts of fumed silica 80-100 parts of filler; Component B comprises the following raw materials in parts by weight: 40-60 parts of polyetheramine, Isophorone diamine 20-30 parts, 10-20 parts of low molecular weight polyamide 10-15 parts of fumed silica 60-80 parts of filler 2.4.6-Tris(dimethylaminomethyl)phenol 1-10 parts.

[0006] Preferably, component A comprises the following raw materials in parts by weight: 40 parts of bisphenol A epoxy resin 20 parts of heterocyclic epoxy resin 15 parts of multifunctional epoxy resin. 10 parts diluent 20 parts toughening agent 12 parts of fumed silica 80 parts of filler; Component B comprises the following raw materials in parts by weight: 40 parts of polyetheramine, 30 parts of isophorone diamine 10 parts of low molecular weight polyamide 12 parts of fumed silica 80 parts of filler 2.4.6-Tris(dimethylaminomethyl)phenol 1 part.

[0007] Preferably, the heterocyclic epoxy resin includes one or more of hydantoin epoxy resin, cyanuric acid epoxy resin, and fused-ring naphthalene type epoxy resin, with an epoxy value of 0.44 to 0.74.

[0008] Preferably, the multifunctional epoxy resin includes one or more of o-cresol epoxy resin, TDE85 epoxy resin, and AFG90 epoxy resin.

[0009] Preferably, the diluent is one or more of allyl glycidyl ether, butyl glycidyl ether, and glycidyl methacrylate.

[0010] Preferably, the toughening agent is one or more of carboxyl-terminated liquid nitrile rubber, hydroxyl-terminated liquid nitrile rubber, and epoxy-terminated liquid nitrile rubber, with a molecular weight of 1700~4500.

[0011] Preferably, the filler includes one or more of silica fume, calcium carbonate, ACR impact retardant, and aluminum hydroxide.

[0012] Preferably, the molecular weight of the polyetheramine is 230 to 2000.

[0013] Preferably, the low molecular weight polyamide is 200 low molecular weight polyamide or 650 low molecular weight polyamide.

[0014] This invention provides a method for preparing the high-strength, high-toughness, salt spray resistant epoxy structural adhesive, comprising the following steps: mixing component A and component B to obtain the high-strength, high-toughness, salt spray resistant epoxy structural adhesive; The preparation method of component A is as follows: bisphenol A epoxy resin, heterocyclic epoxy resin, multifunctional epoxy resin and diluent are mixed evenly, toughening agent and fumed silica are added and mixed evenly, and finally filler is added and mixed evenly. Vacuum degassing is performed to obtain component A. The preparation method of component B is as follows: polyetheramine, isophorone diamine and low molecular weight polyamide are mixed evenly, then fumed silica is added and mixed evenly, and finally filler is added and mixed evenly. Vacuum degassing is performed to obtain component B.

[0015] This invention provides an application of the high-strength, high-toughness, salt spray resistant epoxy structural adhesive, which is used in wind turbine blades.

[0016] The beneficial effects of this invention are that the epoxy structural adhesive of this invention has excellent mechanical and heat resistance properties. By introducing a fused-ring naphthalene structure into the epoxy backbone, it has excellent mechanical and heat resistance properties. Furthermore, by using a multifunctional epoxy resin, the cured product forms a tight three-dimensional network structure, which further improves the mechanical and heat resistance properties, thus meeting the requirements of wind turbine blades for epoxy structural adhesives.

[0017] This invention involves reacting low-molecular-weight polyamide and reactive nitrile rubber with epoxy resin to link flexible molecules into the epoxy resin. These molecules form a "sea-island structure" with the rigid groups in the epoxy resin, acting as stress concentration points to improve toughness. Then, ACR impact modifier and active silica powder are added. On one hand, this fills in defects such as bubbles generated during the epoxy resin curing process, reducing weak points in the epoxy resin. On the other hand, the ACR impact modifier exhibits shear yielding upon impact, absorbing a large amount of impact energy, thereby significantly improving the toughness of the epoxy resin.

[0018] The epoxy structural adhesive of this invention has a long service life in harsh environments. By adding hydantoin epoxy resin, heterocyclic molecules are enriched on the material surface. Utilizing the excellent corrosion resistance, salt spray resistance, weather resistance, and electrical tracking resistance of hydantoin epoxy resin, the service life of the epoxy structural adhesive in harsh environments can be significantly improved. Detailed Implementation

[0019] To facilitate understanding of the present invention, it will be described more fully and in detail below, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0020] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0021] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0022] Example 1 A high-strength, high-toughness, salt spray-resistant epoxy structural adhesive comprises component A and component B in a mass ratio of 100:28, wherein component A comprises the following raw materials in parts by mass: Bisphenol A epoxy resin (E51) 40g 20g of Hein epoxy resin AFG-90 epoxy resin 15g 10g of allyl glycidyl ether 20g of carboxyl-terminated liquid nitrile rubber 12g of fumed silica ACR impact retardant 20g, 50g of silicon micro powder Calcium carbonate 30g.

[0023] Component B comprises the following raw materials in parts by weight: Polyetheramine (D400) 40g Isophorone diamine 30g 10 g of 200 low molecular weight polyamide 12g of fumed silica 50g of silicon micro powder 30g of aluminum hydroxide 2.4.6-Tris(dimethylaminomethyl)phenol 1g.

[0024] The preparation method of the epoxy structural adhesive in this embodiment includes the following steps: (1) Preparation of component A: 40g of bisphenol A epoxy resin, 20g of hydantoin epoxy resin, 15g of AFG90 epoxy resin, and 10g of allyl glycidyl ether were added to a reactor and dispersed for 20 minutes at a dispersion rate of 600 rpm. Next, 20g of carboxyl-terminated liquid nitrile rubber and 12g of fumed silica were added and dispersed for 20 minutes at a dispersion rate of 600 rpm. Then, 20g of ACR impact modifier, 50g of silica powder, and 30g of calcium carbonate were added sequentially and rapidly dispersed for 30 minutes at a dispersion rate of 1000 rpm. Finally, vacuum degassing was performed to obtain component A. (2) Preparation of component B: First, 40g of polyetheramine, 30g of isophorone diamine, 10g of low molecular weight polyamide, and 1g of 2,4,6-tris(dimethylaminomethyl)phenol were added to a reactor and dispersed for 20 minutes at a dispersion rate of 600 rpm. Next, 12g of fumed silica was added and dispersed for another 20 minutes at a dispersion rate of 600 rpm. Then, 50g of silica powder and 30g of aluminum hydroxide were added and rapidly dispersed for 30 minutes at a dispersion rate of 1000 rpm. Finally, vacuum degassing was performed to obtain component B.

[0025] The performance test results of the epoxy structural adhesive prepared in this embodiment are shown in Table 1.

[0026] Example 2 A high-strength, high-toughness, salt spray-resistant epoxy structural adhesive comprises component A and component B in a mass ratio of 100:32, wherein component A comprises the following raw materials in parts by mass: Bisphenol A epoxy resin (E51) 50g, 25g of Hein epoxy resin AFG-90 epoxy resin 20g 8g of allyl glycidyl ether 15g of carboxyl-terminated liquid nitrile rubber 10g of fumed silica ACR impact retardant 20g; 60g of silicon micro powder; Component B comprises the following raw materials in parts by weight: Polyetheramine (D400) 50g, Isophorone diamine 30g 15 g of 650 low molecular weight polyamide 10g of fumed silica 40g of silicon micro powder; 20g of aluminum hydroxide. 2.4.6-Tris(dimethylaminomethyl)phenol 1g.

[0027] The preparation method of the epoxy structural adhesive in this embodiment includes the following steps: (1) Preparation of component A: 50g of bisphenol A epoxy resin, 25g of hydantoin epoxy resin, 20g of AFG-90 epoxy resin, and 8g of allyl glycidyl ether were added to a reactor and dispersed for 20 minutes at a dispersion rate of 600 rpm. Then, 15g of carboxyl-terminated liquid nitrile rubber and 10g of fumed silica were added and dispersed for 20 minutes at a dispersion rate of 600 rpm. Next, 20g of ACR impact modifier and 60g of silica powder were added sequentially and rapidly dispersed for 30 minutes at a dispersion rate of 1000 rpm. Finally, vacuum degassing was performed to obtain component A. (2) Preparation of component B: First, 50g of polyetheramine, 30g of isophorone diamine, 15g of low molecular weight polyamide, and 1g of 2,4,6-tris(dimethylaminomethyl)phenol were added to a reactor and dispersed for 20 minutes at a dispersion rate of 600 rpm. Next, 10g of fumed silica was added and dispersed for another 20 minutes at a dispersion rate of 600 rpm. Then, 40g of silica powder and 20g of aluminum hydroxide were added and rapidly dispersed for 30 minutes at a dispersion rate of 1000 rpm. Finally, vacuum degassing was performed to obtain component B.

[0028] The performance test results of the epoxy structural adhesive prepared in this embodiment are shown in Table 1.

[0029] Example 3 A high-strength, high-toughness, salt spray-resistant epoxy structural adhesive comprises component A and component B in a mass ratio of 100:30, wherein component A comprises the following raw materials in parts by mass: Bisphenol A epoxy resin (E51) 45g 30g of Hein epoxy resin AFG-90 epoxy resin 10g 6g of allyl glycidyl ether 18g of carboxyl-terminated liquid nitrile rubber 15g of fumed silica ACR impact retardant 30g; 40g of silicon micro powder; Calcium carbonate 20g Component B comprises the following raw materials in parts by weight: Polyetheramine (D400) 50g, Isophorone diamine 20g, 20 g of 200 low molecular weight polyamide 15g of fumed silica 40g of silicon micro powder; 30g of aluminum hydroxide. 2.4.6-Tris(dimethylaminomethyl)phenol 1g.

[0030] The preparation method of the epoxy structural adhesive in this embodiment includes the following steps: (1) Preparation of component A: 45g of bisphenol A epoxy resin, 30g of hydantoin epoxy resin, 10g of AFG-90 epoxy resin, and 6g of allyl glycidyl ether were added to a reaction vessel and dispersed for 20 minutes at a dispersion rate of 600 rpm. Next, 18g of carboxyl-terminated liquid nitrile rubber and 15g of fumed silica were added and dispersed for 20 minutes at a dispersion rate of 600 rpm. Then, 30g of ACR impact modifier, 40g of silica powder, and 20g of calcium carbonate were added sequentially and rapidly dispersed for 30 minutes at a dispersion rate of 1000 rpm. Finally, vacuum degassing was performed to obtain component A. (2) Preparation of component B: First, 50g of polyetheramine, 20g of isophorone diamine, 20g of low molecular weight polyamide, and 1g of 2,4,6-tris(dimethylaminomethyl)phenol were added to a reactor and dispersed for 20 minutes at a dispersion rate of 600 rpm. Next, 15g of fumed silica was added and dispersed for another 20 minutes at a dispersion rate of 600 rpm. Then, 40g of silica powder and 30g of aluminum hydroxide were added and rapidly dispersed for 30 minutes at a dispersion rate of 1000 rpm. Finally, vacuum degassing was performed to obtain component B.

[0031] The performance test results of the epoxy structural adhesive prepared in this embodiment are shown in Table 1.

[0032] Comparative Example 1 Compared with Example 1, the difference is that in component A, the weight of bisphenol A epoxy resin (E51) is 60g, and the hydantoin epoxy resin is removed. Otherwise, it is the same as Example 1.

[0033] Comparative Example 2 Compared with Example 1, Comparative Example 2 differs in that the weight of bisphenol A epoxy resin (E51) in component A is 55g, and AFG-90 epoxy resin is removed; otherwise, it is the same as Example 1.

[0034] Comparative Example 3 Compared with Example 1, Comparative Example 3 differs in that in component B, 200 low molecular weight polyamide is replaced with polyamide 12 of normal molecular weight, while the rest is the same as in Example 1.

[0035] Comparative Example 4 Compared with Example 1, Comparative Example 4 differs in that the weight of polyetheramine in component B is 51g, and 2,4,6-tris(dimethylaminomethyl)phenol is removed; otherwise, it is the same as Example 1.

[0036] Comparative Example 5 An epoxy resin structural adhesive includes component A and component B in a mass ratio of 100:45, wherein component A comprises the following raw materials in parts by mass: Bisphenol A epoxy resin (E51) 60g, 20g of bisphenol F epoxy resin 15g of fumed silica; 10g of allyl glycidyl ether 5g of resorcinol 40g of silicon micro powder Calcium carbonate 20g.

[0037] Component B comprises the following raw materials in parts by weight: 38g of polyetheramine Isophorone diamine 36g, Diethylenetriamine 5 g, 10g of fumed silica 40g of silicon micro powder; The preparation method of the epoxy structural adhesive in Comparative Example 4 includes the following steps: (1) Preparation of component A: 60g of bisphenol A epoxy resin, 20g of bisphenol F epoxy resin and 10g of allyl glycidyl ether were added to a reaction vessel and dispersed at low speed for 10min (500 r / min). Then, 5g of resorcinol and 15g of fumed silica were added and dispersed at low speed for 10min (500 r / min). Next, 40g of silica powder and 20g of calcium carbonate were added and dispersed at high speed for 30min (1200 r / min). Finally, the mixture was degassed under vacuum for 20min to obtain component A. (2) Preparation of component B: 38g of polyetheramine, 36g of isophorone diamine and 5g of diethylenetriamine were added to the reactor and dispersed at low speed for 10 min (500 r / min). Then 10g of fumed silica was added and dispersed at low speed for 10 min (500 r / min). Next, 40g of silica powder was added and dispersed at high speed for 30 min (1200 r / min). Finally, the mixture was degassed under vacuum for 20 min to obtain component B.

[0038] The performance test results of the epoxy structural adhesive prepared in this comparative example are shown in Table 1.

[0039] Comparative Example 6 An epoxy resin structural adhesive includes component A and component B in a mass ratio of 100:40, wherein component A comprises the following raw materials in parts by mass: Bisphenol A epoxy resin (E51) 50g, 30g of o-cresol formaldehyde epoxy resin 15g of fumed silica; 15g of allyl glycidyl ether 10g of resorcinol 60g of silicon micro powder; Calcium carbonate 30g Component B comprises the following raw materials in parts by weight: 28g of polyetheramine Isophorone diamine 44g Diethylenetriamine 5 g, 15g of fumed silica 50g of silicon micro powder; The preparation method of the comparative epoxy structural adhesive includes the following steps: (1) Preparation of component A: 50g of bisphenol A epoxy resin, 30g of o-cresol epoxy resin and 15g of allyl glycidyl ether were added to a reaction vessel and dispersed at low speed for 10min (500 r / min). Then, 10g of resorcinol and 15g of fumed silica were added and dispersed at low speed for 10min (500 r / min). Next, 60g of silica powder and 30g of calcium carbonate were added and dispersed at high speed for 30min (1200 r / min). Finally, the mixture was degassed under vacuum for 20min to obtain component A. (2) Preparation of component B: 28g of polyetheramine, 44g of isophorone diamine and 5g of diethylenetriamine were added to the reactor and dispersed at low speed for 10 min (500 r / min). Then 15g of fumed silica was added and dispersed at low speed for 10 min (500 r / min). Next, 50g of silica powder was added and dispersed at high speed for 30 min (1200 r / min). Finally, the mixture was degassed under vacuum for 20 min to obtain component B.

[0040] The performance test results of the epoxy structural adhesive prepared in this comparative example are shown in Table 1.

[0041] Table 1 Performance tests of the examples and comparative examples

[0042] Table 1 shows that introducing aromatic ring structures into the epoxy resin backbone using hydantoin and AF-90 epoxy resins can improve hardness and heat resistance. Furthermore, the addition of hydantoin epoxy resin in this invention primarily enhances the specific tracking coefficient (reaching 600V) and salt spray resistance of the structural adhesive. Hydantoin epoxy resin also improves the toughness of the epoxy resin. Isophorone diamine and low-molecular-weight polyamides, containing long, flexible curing agent aliphatic carbon chains, can act as internal toughening agents, giving the cured epoxy resin a certain degree of toughness.

[0043] In summary, the wind turbine epoxy structural adhesive of the present invention has higher strength, higher fatigue toughness, and better salt spray resistance compared with commercially available wind turbine blade structural adhesives. Therefore, the wind turbine epoxy structural adhesive of the present invention has good application prospects and market value.

[0044] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.

[0045] One or more embodiments in this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.

Claims

1. A high-strength, high-toughness, salt spray-resistant epoxy structural adhesive, characterized in that, It includes component A and component B, with a weight ratio of component A to component B of 100:25~35; Component A comprises the following raw materials in parts by weight. 40-50 parts of bisphenol A epoxy resin. 20-30 parts of heterocyclic epoxy resin. 10-20 parts of multifunctional epoxy resin 1-10 parts of diluent 10-20 parts toughening agent 10-15 parts of fumed silica 80-100 parts of filler; Component B comprises the following raw materials in parts by weight: 40-60 parts of polyetheramine, Isophorone diamine 20-30 parts, 10-20 parts of low molecular weight polyamide 10-15 parts of fumed silica 60-80 parts of filler 2.4.6-Tris(dimethylaminomethyl)phenol 1-10 parts; The heterocyclic epoxy resin is a hydantoin epoxy resin with an epoxy value of 0.44~0.74; The toughening agent is one or more of carboxyl-terminated liquid nitrile rubber, hydroxyl-terminated liquid nitrile rubber, and epoxy-terminated liquid nitrile rubber, with a molecular weight of 1700~4500. The low molecular weight polyamide is either 200 low molecular weight polyamide or 650 low molecular weight polyamide.

2. The high-strength, high-toughness, salt spray-resistant epoxy structural adhesive as described in claim 1, characterized in that, The multifunctional epoxy resin includes one or more of o-cresol epoxy resin, TDE85 epoxy resin, and AFG90 epoxy resin.

3. The high-strength, high-toughness, salt spray-resistant epoxy structural adhesive as described in claim 1, characterized in that, The diluent is one or more of allyl glycidyl ether, butyl glycidyl ether, and glycidyl methacrylate.

4. The high-strength, high-toughness, salt spray-resistant epoxy structural adhesive as described in claim 1, characterized in that, The filler includes one or more of the following: silica powder, calcium carbonate, ACR impact retardant, and aluminum hydroxide.

5. The high-strength, high-toughness, salt spray-resistant epoxy structural adhesive as described in claim 1, characterized in that, The molecular weight of the polyetheramine is 230~2000.

6. A method for preparing a high-strength, high-toughness, salt spray-resistant epoxy structural adhesive as described in any one of claims 1-5, characterized in that, The process includes the following steps: mixing component A and component B to obtain a high-strength, high-toughness, salt spray resistant epoxy structural adhesive. The preparation method of component A is as follows: bisphenol A epoxy resin, heterocyclic epoxy resin, multifunctional epoxy resin and diluent are mixed evenly, toughening agent and fumed silica are added and mixed evenly, and finally filler is added and mixed evenly. Vacuum degassing is performed to obtain component A. The preparation method of component B is as follows: polyetheramine, isophorone diamine and low molecular weight polyamide are mixed evenly, then fumed silica is added and mixed evenly, and finally filler is added and mixed evenly. Vacuum degassing is performed to obtain component B.

7. An application of the high-strength, high-toughness, salt spray-resistant epoxy structural adhesive as described in any one of claims 1-5, characterized in that, The high-strength, high-toughness, salt spray-resistant epoxy structural adhesive is used in wind turbine blades.

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