Low-density high-strength wind power epoxy structural adhesive and preparation method thereof

Abstract

The invention discloses a low-density high-strength wind power epoxy structural adhesive which is composed of a component A and a component B according to the mass ratio of 10: (4-6), wherein the component A comprises the following raw materials in parts by weight: 60-80 parts of epoxy resin, 3-7 parts of a diluent, 0.5-2 parts of a coupling agent, 5-6 parts of a flexibilizer, 0.1-2 parts of an auxiliary agent, 4-6 parts of a thixotropic agent, 1-15 parts of a novel functional filler and 2-10 parts of a second functional filler; and the component B comprises the following raw materials in parts by weight: 75-85 parts of an amine curing agent, 0.1-2 parts of an auxiliary agent, 5-10 parts of a thixotropic agent, 1-15 parts of a novel functional filler and 1-10 parts of a second functional filler. The low-density and high-strength wind power epoxy structural adhesive has the advantages of low specific gravity, high thixotropy, high strength, good body mechanical property and bonding property, excellent acid and alkali resistance and fatigue resistance, the density is greatly reduced by introducing the novel functional filler, the use amount of the wind power epoxy structural adhesive can be saved, the cost is reduced in a synergistic manner, and the cost is reduced. And the development of the blade industry is promoted.

Description

Technical Field

[0001] The present invention belongs to the technical field of adhesives, and in particular relates to a low-density and high-strength wind power epoxy structural adhesive and a preparation method thereof. Background Art

[0002] Driven by the rapid development of wind power technology and national support for the green energy generation industry, wind energy has become the fastest-growing green renewable energy source in recent years and is poised to become the primary source of incremental power in the future. Compared to fossil fuels, wind energy has attracted attention worldwide due to its advantages such as large capacity, environmental friendliness, and low overall management costs.

[0003] With the rapid development and maturation of the wind power industry, manufacturing processes are constantly being upgraded, power generation costs are continuously decreasing, and, coupled with limited wind farm resources, wind turbine blades are increasingly being developed in larger sizes, placing higher demands on blade quality. Epoxy structural adhesives, as the "adhesive" of wind turbine blade materials, play a crucial role in the blade's construction, and their performance directly determines the quality of the blade itself.

[0004] The increase in blade size inevitably requires more epoxy structural adhesive, which increases blade weight. This can lead to instability and vibration during operation, directly impacting power generation efficiency and indirectly increasing manufacturing costs. Furthermore, the continuous increase in blade size requires structural adhesives with improved bonding properties, higher strength, and other properties. Developing a low-density, high-strength epoxy structural adhesive for wind turbines is imperative.

[0005] Fillers are widely used in epoxy structural adhesives as a cost-effective raw material. All commercially available epoxy structural adhesives incorporate fillers to some degree. However, the fillers used in epoxy structural adhesives for wind turbine blades are mostly heavy silica powder, wollastonite, mica powder, and other fillers. Excessive use of these fillers increases the density of the epoxy structural adhesive, directly increasing blade weight and raising a series of safety issues. Furthermore, the increased density of epoxy structural adhesives for wind turbine blades leads to increased adhesive consumption, increasing blade manufacturing costs.

[0006] Patent CN112778950A discloses a high-efficiency, medium-temperature, fast-curing epoxy structural adhesive and its preparation method for wind turbine blade mold bonding. This method uses multiple fillers and does not disclose the density of a single component. Furthermore, the epoxy structural adhesive produced by this method has an impact strength of only 8 to 12 MPa.

[0007] Patent CN106753134B discloses an epoxy structural adhesive suitable for mold bonding of salt spray-resistant, heat-resistant wind turbine blades and its preparation method. This method uses a high-density functional filler: a mixture of fibrous short glass fibers, nano-calcium carbonate, spherical silica, and pure calcium silicate or pure magnesium silicate, with a mass ratio of 1:10:20:6. The use of these high-density fillers undoubtedly increases the density of the structural adhesive, and the method does not disclose the density of the individual components.

[0008] Patent CN107903857A discloses a high-strength, high-toughness epoxy film adhesive for wind turbine blades and its preparation method. Although this method produces a high-strength epoxy film adhesive, the use of 30-50 parts of high-density active silica powder increases the adhesive's density to a certain extent. Furthermore, the method does not disclose the density of the individual components.

[0009] Patent CN106833475A discloses an epoxy adhesive for megawatt-class wind turbine blades and its preparation method. The filler used includes 10-30 parts glass fiber powder, 10-30 parts activated silica powder, and 5-15 parts activated calcium carbonate. This method addresses the trade-off between strength and toughness in epoxy adhesives, but it uses a relatively high proportion of the heavier activated silica powder, and the density of the individual components is not disclosed. Summary of the Invention

[0010] An object of the present invention is to solve at least the above problems and / or disadvantages and to provide at least the advantages which will be described hereinafter.

[0011] In order to achieve these objects and other advantages of the present invention, a low-density and high-strength wind power epoxy structural adhesive is provided, wherein the low-density and high-strength wind power epoxy structural adhesive is composed of component A and component B in a mass ratio of 10:4-6; Component A comprises the following raw materials in parts by weight: 60-80 parts of epoxy resin, 3-7 parts of diluent, 0.5-2 parts of coupling agent, 5-6 parts of toughening agent, 0.1-2 parts of auxiliary agent, 4-6 parts of thixotropic agent, 1-15 parts of new functional filler, and 2-10 parts of second functional filler; Component B comprises the following raw materials in parts by weight: 75-85 parts of amine curing agent, 0.1-2 parts of auxiliary agent, 5-10 parts of thixotropic agent, 1-15 parts of new functional filler, and 1-10 parts of second functional filler.

[0012] Preferably, the epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, alicyclic epoxy resin, and multifunctional epoxy resin.

[0013] Preferably, the epoxy resin is bisphenol A epoxy resin and bisphenol F epoxy resin; the mass ratio of the bisphenol A epoxy resin to the bisphenol F epoxy resin is 3-6:1-4.

[0014] Preferably, the diluent is one or more of carbon 12-14 decyl glycidyl ether, carbon 16-18 decyl glycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, propylene oxide methyl ether, phenyl glycidyl ether, allyl glycidyl ether, n-butyl glycidyl ether, glycidyl methacrylate, and polypropylene glycol diglycidyl ether; more preferably, 1,4-butanediol diglycidyl ether.

[0015] Preferably, the toughening agent is one or more of a polyurethane-modified epoxy resin toughening agent, a core-shell particle toughening agent, a thermoplastic resin toughening agent, an epoxy-modified rubber toughening agent, and an isocyanate-modified rubber toughening agent.

[0016] Preferably, the toughening agent is a core-shell rubber epoxy toughening agent.

[0017] Preferably, the coupling agent is one or more of a silane coupling agent, a titanate coupling agent, and an aluminate coupling agent.

[0018] Preferably, the auxiliary agent is one or more of bisphenol A, phenol, resorcinol, o-phenol, pigment yellow, and pigment blue.

[0019] Preferably, the auxiliary agents of component A are resorcinol and pigment yellow; the mass ratio of resorcinol to pigment yellow is 10:1.

[0020] Preferably, the auxiliary agent of component B is pigment blue.

[0021] Preferably, the thixotropic agent is one or more of hydrophobic fumed silica, organic bentonite, and hydroxyethyl cellulose.

[0022] Preferably, the amine curing agent is one or more of diethylamine, diethylenetriamine, divinylpropylamine, triethylamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethylenepolyamine, isophoronediamine, diaminodiphenylmethane, meta-phenylenediamine, diaminodiphenyl sulfone, meta-phenylenediamine, 1,3-cyclohexanedimethylamine, 4,4-diaminodicyclohexylmethane, polyamide, and polyetheramine.

[0023] Preferably, the amine curing agent is isophorone diamine, polyamide and polyetheramine; the mass ratio of isophorone diamine, polyamide and polyetheramine is 8-12:5-15:55-65.

[0024] Preferably, the novel functional filler is modified hollow glass microspheres; and the second functional filler is one or more of nano-calcium carbonate, diatomaceous earth, chopped glass fiber and montmorillonite.

[0025] Preferably, the preparation method of the modified hollow glass microspheres is: soaking the hollow glass microspheres in 1 mol / L HCl for 1 to 2 hours, then alkali-washing the hollow glass microspheres with 1 mol / L NaOH to remove surface stains, and finally washing with distilled water until neutral, and drying at 100 to 130 ° C for 20 to 30 hours; pouring the dried hollow glass microspheres into a methanol solution of 1 to 10 wt% silane coupling agent and stirring for 8 to 16 hours, and drying at 200 to 400 ° C for 4 to 8 hours to obtain modified hollow glass microspheres; wherein the mass ratio of the silane coupling agent to the hollow glass microspheres is 0.1 to 0.5:1; the particle size of the hollow glass beads is one or more of 2 to 15 μm, 30 to 40 μm, and 45 to 85 μm.

[0026] Preferably, the second functional filler is chopped glass fiber and montmorillonite; the mass ratio of the chopped glass fiber to montmorillonite is 1:8.

[0027] A method for preparing the low-density, high-strength wind power epoxy structural adhesive as described above comprises the following steps: Step 1, preparation of component A: epoxy resin, diluent, coupling agent, toughening agent, and additive are mixed and stirred uniformly at a stirring speed of 5-15 rpm, then a thixotropic agent is added, high-speed dispersion is started, and the dispersion speed is 2000-3000 rpm to form thixotropy, and then the new functional filler and the second functional filler are added in sequence, and high-speed dispersion is uniformly performed, vacuum degassing is performed, and then filtering and packaging are performed to obtain the component A; Step 2, preparation of component B: the amine curing agent and the auxiliary agent are mixed and stirred evenly at a stirring speed of 5-15 rpm, and then the thixotropic agent is added and dispersed at a high speed at a dispersion speed of 2000-3000 rpm to form thixotropy. Then, the new functional filler and the second functional filler are added in sequence, dispersed evenly at high speed, vacuum degassed, and then filtered and packaged to obtain the B component.

[0028] An application of the low-density, high-strength wind turbine epoxy structural adhesive as described above in wind turbine blades.

[0029] The present invention has at least the following beneficial effects: It discloses a low-density, high-strength wind turbine epoxy structural adhesive and its preparation method. This invention avoids the use of high-density fillers and utilizes lightweight modified hollow glass microspheres. By optimizing the formulation of the various raw material components, the density of the epoxy structural adhesive is significantly reduced, while also improving its mechanical and bonding properties. This significant reduction in epoxy structural adhesive density can save on epoxy structural adhesive usage, reduce costs through increased efficiency, and promote the development of the blade industry.

[0030] Other advantages, objectives and features of the present invention will be reflected in part from the following description and will be understood by those skilled in the art through study and practice of the present invention. DETAILED DESCRIPTION

[0031] The present invention is described in further detail below so that those skilled in the art can implement the invention with reference to the description.

[0032] It should be understood that terms such as “having”, “including” and “comprising” used herein do not preclude the existence or addition of one or more other elements or combinations thereof.

[0033] In the following examples and comparative examples, the diluent used is 1,4-butanediol diglycidyl ether, the toughening agent is a core-shell rubber epoxy toughening agent, the coupling agent is a silane coupling agent KH560, the auxiliary agents of component A are resorcinol and pigment yellow (mass ratio 10:1), the auxiliary agent of component B is pigment blue, the thixotropic agent is hydrophobic fumed silica, the polyamide is polyamide V140, the polyetheramine is D400, the secondary functional filler is chopped glass fiber and montmorillonite (mass ratio 1:8), and the particle size of the hollow glass microspheres is 30~40μm.

[0034] Examples 1-6 and Comparative Examples 1-7 A low-density, high-strength wind power epoxy structural adhesive, the amounts of the raw materials of each component are shown in Table 1 and Table 2 (by weight); A method for preparing a low-density, high-strength wind power epoxy structural adhesive comprises the following steps: Step 1, preparation of component A: epoxy resin (bisphenol A epoxy resin, bisphenol F epoxy resin), diluent, coupling agent, toughening agent, and additives are added to a double planetary stirring kettle and mixed and stirred evenly at a stirring speed of 10 rpm ± 2 rpm. Then, a thixotropic agent (hydrophobic fumed silica) is added and high-speed dispersion is started at a speed of 2500 rpm ± 10 rpm to form thixotropy. Then, a new functional filler (modified hollow glass microspheres) and a second functional filler are added in sequence and dispersed evenly at high speed. Vacuum degassing is performed, and then the component A is filtered and packaged for use. Step 2, Preparation of Component B: Add an amine curing agent (isophorone diamine, polyamide, polyetheramine) and an additive to a double planetary stirred tank and mix and stir evenly at a stirring speed of 10 rpm ± 2 rpm. Then add a thixotropic agent (hydrophobic fumed silica) and disperse with high-speed stirring at a speed of 2500 rpm ± 10 rpm to form thixotropy. Then, add a new functional filler (modified hollow glass microspheres) and a second functional filler in sequence, disperse evenly at high speed, degas under vacuum, and then filter and package to obtain the B component for later use. Among them, the preparation method of modified hollow glass microspheres is as follows: soaking the hollow glass microspheres in 1 mol / L HCl for 1 hour, then using 1 mol / L NaOH to alkaline wash the hollow glass microspheres to fully remove surface stains, and finally washing them with distilled water until neutral, placing them in a 110°C oven to dry for 24 hours to remove moisture; pouring the dried hollow glass microspheres into a 3 wt% silane coupling agent (KH560) methanol solution and stirring for 12 hours, and drying them at 300°C for 6 hours to obtain modified hollow glass microspheres; wherein, the mass ratio of KH560 to hollow glass microspheres is 0.3:1.

[0035] Table 1 Amount of raw materials of each component in Examples 1-6 Table 2 Amount of raw materials of each component in Comparative Examples 1-7 The performance of Examples 1-6 and Comparative Examples 1-7 was tested. Components A and B were mixed and stirred at a mass ratio of 2:1, and then cured at 25°C for 24 hours and 70°C for 8 hours to obtain a cured product. Specifically comprising: (1) Single component density (GB / T 13354) test; (2) After the cured product is cut, the bulk tensile mechanics (GB / T 1040.2) test is performed; (3) After the solidified material is cut, the impact mechanics (GB / T 1043.1) test is performed on the solidified material; (4) 3.0mm tensile shear performance (GFRP / GFRP) (GB / T7124) test; The test results are shown in Table 3.

[0036] Comparison between Example 1 and Comparative Examples 1-2 shows that the modified hollow glass microspheres are not added to component B of Comparative Example 1, and the modified hollow glass microspheres are not added to component A of Comparative Example 2. It can be seen that the density of the component without modified hollow glass microspheres is higher, while the tensile strength, impact strength, and shear strength are all reduced.

[0037] From the comparison between Examples 1-2 and Comparative Example 3, it can be seen that after adding the modified hollow glass microspheres, the density of each component in Examples 1-2 shows a downward trend compared with Comparative Example 3 (without adding the modified hollow glass microspheres). The appropriate addition of modified hollow glass microspheres can improve the strength of the epoxy structural adhesive to a certain extent, so that it can obtain better performance.

[0038] From the comparison of Examples 1-6, it can be seen that by adjusting the dosage ratio of the raw materials of each component, the density of each component and the mechanical properties of the epoxy structural adhesive can be adjusted; among them, Example 6 has the highest addition amount of modified hollow glass microspheres, the lowest density of each component, and also has good mechanical properties; the epoxy structural adhesive of Example 4 has the highest tensile strength and impact strength.

[0039] From the comparison between Examples 3-6 and Comparative Examples 4-7, it can be seen that the addition of modified hollow glass microspheres is beneficial to reducing the density of each component and improving the mechanical properties of the epoxy structural adhesive.

[0040] In summary, the wind power epoxy structural adhesive obtained by the present invention has the advantages of low density, high thixotropy, high strength, good bulk mechanical properties and bonding properties, excellent acid and alkali resistance and fatigue resistance, and can be used in wind power blades.

[0041] Table 3 Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and embodiments shown and described herein.

Claims

1. A low-density, high-strength wind power epoxy structural adhesive, characterized in that: It is composed of component A and component B in a mass ratio of 10:4~6; Component A comprises the following raw materials in parts by weight: 60-80 parts of epoxy resin, 3-7 parts of diluent, 0.5-2 parts of coupling agent, 5-6 parts of toughening agent, 0.1-2 parts of auxiliary agent, 4-6 parts of thixotropic agent, 1-15 parts of new functional filler, and 2-10 parts of second functional filler; Component B comprises the following raw materials in parts by weight: 75-85 parts of amine curing agent, 0.1-2 parts of auxiliary agent, 5-10 parts of thixotropic agent, 1-15 parts of new functional filler, and 1-10 parts of second functional filler.

2. The low-density, high-strength wind power epoxy structural adhesive according to claim 1, characterized in that: The epoxy resin is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin, hydrogenated bisphenol A epoxy resin, alicyclic epoxy resin, and multifunctional epoxy resin.

3. The low-density, high-strength wind power epoxy structural adhesive according to claim 1, characterized in that: The diluent is one or more of carbon 12 to 14 alkyl glycidyl ether, carbon 16 to 18 alkyl glycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, propylene oxide methyl ether, phenyl glycidyl ether, allyl glycidyl ether, n-butyl glycidyl ether, glycidyl methacrylate, and polypropylene glycol diglycidyl ether.

4. The low-density, high-strength wind power epoxy structural adhesive according to claim 1, characterized in that: The toughening agent is one or more of a polyurethane modified epoxy resin toughening agent, a core-shell particle toughening agent, a thermoplastic resin toughening agent, an epoxy modified rubber toughening agent, and an isocyanate modified rubber toughening agent.

5. The low-density, high-strength wind power epoxy structural adhesive according to claim 1, characterized in that: The coupling agent is one or more of a silane coupling agent, a titanate coupling agent, and an aluminate coupling agent; The auxiliary agent is one or more of bisphenol A, phenol, resorcinol, o-phenol, pigment yellow, and pigment blue; The thixotropic agent is one or more of hydrophobic fumed silica, organic bentonite, and hydroxyethyl cellulose.

6. The low-density, high-strength wind power epoxy structural adhesive according to claim 1, characterized in that: The amine curing agent is one or more of diethylamine, diethylenetriamine, divinylpropylamine, triethylamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, polyethylenepolyamine, isophoronediamine, diaminodiphenylmethane, meta-phenylenediamine, diaminodiphenyl sulfone, meta-phenylenediamine, 1,3-cyclohexanedimethylamine, 4,4-diaminodicyclohexylmethane, polyamide, and polyetheramine.

7. The low-density, high-strength wind power epoxy structural adhesive according to claim 1, characterized in that: The novel functional filler is modified hollow glass microspheres; the second functional filler is one or more of nano calcium carbonate, diatomaceous earth, chopped glass fiber and montmorillonite.

8. The low-density, high-strength wind power epoxy structural adhesive according to claim 7, characterized in that: The modified hollow glass microspheres are prepared by soaking the hollow glass microspheres in 1 mol / L HCl for 1-2 hours, then alkaline-washing the hollow glass microspheres with 1 mol / L NaOH to remove surface stains, finally washing with distilled water until neutral, and drying at 100-130° C. for 20-30 hours; pouring the dried hollow glass microspheres into a methanol solution containing 1-10 wt% of a silane coupling agent, stirring for 8-16 hours, and drying at 200-400° C. for 4-8 hours to obtain the modified hollow glass microspheres; wherein the mass ratio of the silane coupling agent to the hollow glass microspheres is 0.1-0.5:1; and the particle size of the hollow glass microspheres is one or more of 2-15 μm, 30-40 μm, and 45-85 μm.

9. A method for preparing a low-density, high-strength wind power epoxy structural adhesive according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1, preparation of component A: epoxy resin, diluent, coupling agent, toughening agent, and additive are mixed and stirred uniformly at a stirring speed of 5-15 rpm, then a thixotropic agent is added, high-speed dispersion is started, and the dispersion speed is 2000-3000 rpm to form thixotropy, and then the new functional filler and the second functional filler are added in sequence, and high-speed dispersion is uniformly performed, vacuum degassing is performed, and then filtering and packaging are performed to obtain the component A; Step 2, preparation of component B: the amine curing agent and the auxiliary agent are mixed and stirred evenly at a stirring speed of 5-15 rpm, and then the thixotropic agent is added and dispersed at a high speed at a dispersion speed of 2000-3000 rpm to form thixotropy. Then, the new functional filler and the second functional filler are added in sequence, dispersed evenly at high speed, vacuum degassed, and then filtered and packaged to obtain the B component.

10. Use of the low-density, high-strength wind turbine epoxy structural adhesive according to any one of claims 1 to 8 in wind turbine blades.

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