Recyclable resin composition for wind turbine blade composite materials

Abstract

The present invention discloses a recyclable resin composition for wind turbine blade composite materials. The recyclable resin composition is primarily composed of two components, A and B. Component A primarily comprises a methyl methacrylate (MMA) prepolymer, comonomers R1 and R2, and a catalyst; component B is an initiator system. The recyclable resin composition exhibits excellent room temperature storage stability, an extremely long operating time, rapid curing at medium and low temperatures, high mechanical properties, and low shrinkage. It can be prepared into a recyclable composite material with excellent temperature resistance through various composite molding processes, particularly for applications in wind turbine blade infusion molding.

Description

Technical Field

[0001] The invention belongs to the field of thermoplastic recycling, and in particular relates to a recyclable resin composition for wind turbine blade composite materials. Background Art

[0002] According to the Global Wind Energy Council (GWEC), global wind power installed capacity exceeded 90GW in 2021, and the resin consumed in the production of wind turbine blade composites exceeded 300,000 tons. With the continued development of low-carbon policies, the development trend of wind power remains strong. Currently, the resin consumed in the production of wind turbine blade composites in the market is still mainly thermosetting epoxy resin, and early wind turbine blades are currently facing retirement in large numbers. The recycling of thermosetting epoxy resin composites has become a difficult problem for the current development of the industry.

[0003] CN114656752A and CN114195984A disclose methods for preparing degradable epoxy resin composite materials for wind turbine blades. Wind turbine blades prepared from these degradable epoxy resin compositions exhibit excellent mechanical properties without changing existing process parameters. However, the introduction of degradable chemical bonds through a complex synthesis process increases production costs. Furthermore, the resulting degradation products differ from the original monomers, reducing their applicability and limiting their practical application.

[0004] It can be seen that existing recyclable wind turbine blade composite materials still have problems of high cost and low recycling rate. Summary of the Invention

[0005] The purpose of the present invention is to solve the deficiencies in the prior art and provide a recyclable resin composition, which has the characteristics of low cost, high performance and high recycling rate, and can be used to prepare recyclable wind turbine blade materials through a vacuum infusion molding process.

[0006] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0007] A recyclable resin composition for a wind turbine blade composite material, comprising components in the following mass proportions:

[0008]

[0009] The composition of this invention uses inexpensive MMA prepolymer as its main raw material (compared to traditional epoxy resin systems), effectively reducing blade production costs. Furthermore, PMMA heat recovery technology is becoming increasingly mature, with a recovery rate exceeding 90%. Molecular modification, introducing cyclic and alkoxy structural units, not only enhances the mechanical and heat resistance of the material through crosslinking points, but also overcomes the brittle nature of PMMA, significantly improving its toughness.

[0010] The synthetic reaction formula of the highly active comonomer R1, the synthetic reaction formula of the highly active comonomer R2, and the curing reaction formula of the recyclable resin system and its enhancement mechanism are as follows:

[0011]

[0012] In the present invention, the MMA prepolymer is prepared by homopolymerization of MMA monomer; preferably, the number average molecular weight of the MMA prepolymer is 300-4000; and the viscosity at 25° C. is 50-500 cP.

[0013] In the present invention, the comonomer R1 is synthesized from diisocyanate and hydroxy methacrylate; preferably, the diisocyanate is selected from one or more of diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), and toluene diisocyanate (TDI); preferably, the hydroxy methacrylate is selected from hydroxyethyl methacrylate (HEMA) and / or hydroxypropyl methacrylate (HPMA).

[0014] In the present invention, the preparation method of the comonomer R1 is: diisocyanate and hydroxy methacrylate are mixed and then heated to react; preferably, the molar ratio of the diisocyanate and hydroxy methacrylate is 1:(1-5), preferably 1:(2-3); preferably, the reaction temperature is 25-100°C, preferably 40-80°C, and the reaction time is 0.5-10h, preferably 1-3h.

[0015] In the present invention, the comonomer R2 is synthesized from glycidyl methacrylate (GMA) and methacrylate polyethylene glycol ammonium (MAC-PEG-NH2).

[0016] In one embodiment, the molecular weight of the methacrylate polyethylene glycol amine is 180-2000, preferably 200-500.

[0017] In the present invention, the preparation method of the comonomer R2 is: glycidyl methacrylate (GMA) and methacrylate polyethylene glycol ammonia system are mixed and then heated to react; preferably, the molar ratio of glycidyl methacrylate (GMA) to methacrylate polyethylene glycol ammonia is 1:(1-5); preferably, the reaction temperature is 25-100°C and the reaction time is 0.5-10h.

[0018] In the present invention, the catalyst is selected from one or more of cobalt isooctanoate, potassium isooctanoate, copper isooctanoate, and N,N-dimethylaniline.

[0019] In the present invention, the initiator is selected from one or more of benzoyl peroxide (BPO), di-tert-butyl peroxide (DTBP), tert-butyl peroxy-2-ethylhexanoate (TBPO), tert-butyl peroxy terephthalate (TBPB), and methyl ethyl ketone peroxide (MEKP).

[0020] Another object of the present invention is to provide a method for preparing a recyclable resin-based composite material.

[0021] A preparation method of a recyclable resin-based composite material adopts the above-mentioned recyclable resin composition. The preparation method comprises: compounding the above-mentioned recyclable resin composition with fibers and heating and curing them.

[0022] In the present invention, the fiber is one or more of glass fiber, carbon fiber, aramid fiber, and bamboo fiber; preferably, the mass ratio of the recyclable resin composition to the fiber is 1:(2-6).

[0023] In the present invention, the thermal curing includes pre-curing and post-curing; preferably, the pre-curing temperature is 30-50°C, the time is 1-4h, preferably the temperature is 35-45°C, and the time is 2-3h; preferably, the post-curing temperature is 60-100°C, the time is 1-4h, preferably the temperature is 75-85°C, and the time is 2-3h.

[0024] Another object of the present invention is to provide a recyclable resin-based composite material.

[0025] A recyclable resin-based composite material is prepared by the above-mentioned preparation method. The thermal degradation temperature of the composite material in a nitrogen atmosphere is 180-400°C, preferably 250-350°C.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The recovery rate of resin and its fiber can reach more than 90%, solving the industry problem of recycling and processing of retired wind turbine blades.

[0028] (2) Outstanding economic benefits. Recyclable resin raw materials are cheaper than epoxy resin systems. They can not only reduce the production cost of wind turbine blades by 30%, but also increase the molding efficiency by two times, greatly reducing the production pressure in the industry.

[0029] (3) The resin system solves the problems of difficult initiation, easy explosion, high shrinkage, low strength and low toughness in the low-temperature liquid molding process of MMA by introducing comonomers. DETAILED DESCRIPTION

[0030] The present invention is further described by way of specific examples, which are intended only to illustrate the present invention and do not limit the scope of the present invention.

[0031] The raw materials and their sources are detailed in Table 1.

[0032] Table 1 Raw materials and sources

[0033]

[0034] Other raw materials are commercially available unless otherwise specified.

[0035] The test equipment and standards are detailed in Table 2.

[0036] Table 2 Test equipment and standards

[0037]

[0038]

[0039] Preparation Example 1

[0040] Under nitrogen atmosphere, 50 g of MDI was added to a 250 mL three-necked flask, the temperature of the system was raised to 75°C, and 28.8 g of HPMA was added dropwise through a dropping funnel for half an hour. The system was stirred and reacted for 0.5 h to obtain a highly active comonomer R1-1.

[0041] Preparation Example 2

[0042] Under nitrogen atmosphere, 50 g of IPDI was added to a 500 mL three-necked flask, the temperature of the system was raised to 25°C, and 144 g of HEMA was added dropwise through a dropping funnel for half an hour. The system was stirred and reacted for 10 hours to obtain a highly active comonomer R1-2.

[0043] Preparation Example 3

[0044] Under a nitrogen atmosphere, 60 g of MAC-PEG-NH2 compound was added to a 250 mL three-necked flask, the temperature of the system was raised to 25°C, and 28.8 g of GMA compound was added dropwise through a dropping funnel for half an hour. The system was stirred and continued to react for 10 hours to obtain a highly active comonomer R2-1.

[0045] Preparation Example 4

[0046] Under a nitrogen atmosphere, 60 g of MAC-PEG-NH2 compound was added to a 250 mL three-necked flask, the temperature of the system was raised to 75°C, and 144 g of GMA compound was added dropwise through a dropping funnel for half an hour. The system was stirred and continued to react for 0.5 h to obtain a highly active comonomer R2-2.

[0047] Example 1

[0048] (1) 100 g of MMA prepolymer (molecular weight 300), 10 g of comonomer R1-1, 10 g of comonomer R2-1, 0.01 g of cobalt isooctanoate, and 0.12 g of tert-butyl peroxy-2-ethylhexanoate were weighed and added to a 250 mL flask. The mixture was mixed uniformly by a mechanical stirring paddle, and the air bubbles were removed in a vacuum drying oven at a vacuum degree of 0.08 MPa and a temperature of 25° C. to obtain a resin composition.

[0049] (2) The resin composition was poured into a sealed glass mold, pre-cured at 30°C for 1 hour in a blast oven, and then post-cured at 60°C for 4 hours to obtain a cured PMMA casting sample, and its test specimen was prepared using an engraving machine.

[0050] Example 2

[0051] (1) Weigh 200 g of MMA prepolymer (molecular weight 4000), 5 g of comonomer R1-2, 5 g of comonomer R2-2, 1 g of cobalt isooctanoate, and 5.5 g of tert-butyl peroxy-2-ethylhexanoate, add them to a 500 mL flask, mix them evenly with a mechanical stirrer, and remove bubbles in a vacuum drying oven at a vacuum degree of 0.08 MPa and a temperature of 25°C.

[0052] (2) Heating and curing: The recyclable resin composition obtained in step (1) is poured into a sealed glass mold, pre-cured at 50°C in a blast oven for 4 hours, and then post-cured at 100°C for 1 hour to obtain a cured PMMA casting sample, and its test specimen is prepared by an engraving machine.

[0053] Example 3

[0054] (1) Weigh 100 g of MMA prepolymer (molecular weight 1000), 10 g of comonomer R1-1, 10 g of comonomer R2-1, 0.5 g of cobalt isooctanoate, and 1.2 g of benzoyl peroxide into a 250 mL flask, mix well with a mechanical stirrer, and remove bubbles in a vacuum drying oven at a vacuum degree of 0.08 MPa and a temperature of 25°C.

[0055] (2) Heating and curing: The recyclable resin composition obtained in step (1) is poured into a sealed glass mold, pre-cured at 40°C in a blast oven for 3 hours, and then post-cured at 80°C for 2 hours to obtain a cured PMMA casting sample, and its test specimen is prepared by an engraving machine.

[0056] Example 4

[0057] (1) Weigh 100 g of MMA prepolymer (molecular weight 300), 10 g of comonomer R1-1, 10 g of comonomer R2-1, 0.5 g of N,N-dimethylaniline, and 1.2 g of benzoyl peroxide into a 250 mL flask, mix well with a mechanical stirrer, and remove bubbles in a vacuum drying oven at a vacuum degree of 0.08 MPa and a temperature of 25°C.

[0058] (2) Heating and curing: The recyclable resin composition obtained in step (1) is poured into a sealed glass mold, pre-cured at 40°C in a blast oven for 3 hours, and then post-cured at 80°C for 1 hour to obtain a cured PMMA casting sample, and its test specimen is prepared by an engraving machine.

[0059] Comparative Example 1

[0060] Compared with Example 4, the difference is that the PMMA sample is prepared without comonomers R1 and R2.

[0061] (1) Recyclable resin composition: 100 g of MMA (molecular weight 300) prepolymer, 0.5 g of cobalt isooctanoate, and 1 g of tert-butyl peroxy-2-ethylhexanoate were weighed and added to a 250 mL round-bottom flask. The system composition was mixed evenly by a mechanical stirring paddle, and the bubbles were removed by vacuum drying oven at a vacuum degree of 0.08 MPa and a temperature of 25°C.

[0062] (2) Heating and curing: The recyclable resin composition obtained in step (1) is poured into a sealed glass mold, pre-cured at 40°C in a blast oven for 3 hours, and then post-cured at 80°C for 1 hour to obtain a cured PMMA casting sample, and its test specimen is prepared by an engraving machine.

[0063] Comparative Example 2

[0064] Compared with Example 4, the difference is that there are no comonomers R1 and R2, the catalyst is changed to N,N-dimethylaniline, and the initiator is changed to benzoyl peroxide.

[0065] (1) Weigh 100 g of MMA (molecular weight 300) prepolymer, 0.5 g of N,N-dimethylaniline, and 1 g of benzoyl peroxide into a 250 mL flask, mix well with a mechanical stirrer, and remove bubbles in a vacuum drying oven at a vacuum degree of 0.08 MPa and a temperature of 25°C.

[0066] (2) Heating and curing: The recyclable resin composition obtained in step (1) is poured into a sealed glass mold, pre-cured at 40°C in a blast oven for 3 hours, and then post-cured at 80°C for 1 hour to obtain a cured PMMA casting sample, and its test specimen is prepared by an engraving machine.

[0067] Comparative Example 3

[0068] Compared with Example 4, the difference is that there are no comonomers R1 and R2, the catalyst is changed to N, N-dimethylaniline, the initiator is changed to benzoyl peroxide, and the post-curing time is adjusted to 5 hours.

[0069] (1) Weigh 100 g of MMA (molecular weight 300) prepolymer, 0.5 g of N,N-dimethylaniline, and 1 g of benzoyl peroxide into a 250 mL flask, mix well with a mechanical stirrer, and remove bubbles in a vacuum drying oven at a vacuum degree of 0.08 MPa and a temperature of 25°C.

[0070] (2) Heating and curing: The recyclable resin composition obtained in step (1) is poured into a sealed glass mold, pre-cured at 40°C in a blast oven for 3 hours, and then post-cured at 80°C for 5 hours to obtain a cured PMMA casting sample, and its test specimen is prepared by an engraving machine.

[0071] Example 5

[0072] The steps for preparing and molding recyclable resin-based composite materials are as follows:

[0073] In the vacuum infusion process, a negative pressure is formed in the mold by a vacuum compressor, and the vacuum degree is maintained at 0.1 MPa. The recyclable resin composition of step (1) in Example 1, which has been completely mixed and free of bubbles, is infused into the mold. The mass ratio of resin to fiber is 1:2, and the infusion time is maintained for 1 hour to ensure that the fiber reinforcement material is fully infiltrated. After the recyclable resin composition fills the mold, the mold is heated to a pre-curing temperature of 20°C and maintained for 4 hours to smoothly pass the resin exothermic peak temperature and slowly cure to prevent explosion; then the mold is heated to a post-curing temperature of 100°C and maintained for 1 hour to improve the conversion rate of the resin reaction, thereby preparing the recyclable resin-based composite material, and its test specimen is prepared by an engraving machine.

[0074] Example 6

[0075] The steps for preparing and molding recyclable resin-based composite materials are as follows:

[0076] In the vacuum infusion process, a negative pressure is formed in the mold by a vacuum compressor, and the vacuum degree is maintained at 0.1 MPa. The recyclable resin composition of step (1) in Example 2, which has been completely mixed and free of bubbles, is poured into the mold respectively, with a mass ratio of resin to fiber of 1:6. The infusion time is maintained for 1 hour to ensure that the fiber reinforcement material is fully impregnated. After the recyclable resin composition fills the mold, the mold is heated to a pre-curing temperature of 50°C and maintained for 1 hour to smoothly pass the resin exothermic peak temperature and slowly cure to prevent explosion; then the mold is heated to a post-curing temperature of 60°C and maintained for 4 hours to improve the conversion rate of the resin reaction, thereby preparing the recyclable resin-based composite material, and its test specimens are prepared by an engraving machine.

[0077] Example 7

[0078] The steps for preparing and molding recyclable resin-based composite materials are as follows:

[0079] In the vacuum infusion process, a negative pressure is formed in the mold by a vacuum compressor, and the vacuum degree is maintained at 0.1 MPa. The recyclable resin composition of step (1) in Example 4, which has been completely mixed and de-bubbled, is poured into the mold respectively, with a mass ratio of resin to fiber of 1:4. The infusion time is maintained for 1 hour to ensure that the fiber reinforcement material is fully infiltrated. After the recyclable resin composition fills the mold, the mold is heated to a pre-curing temperature of 40°C and maintained for 3 hours, smoothly passing the resin exothermic peak temperature and slowly curing to prevent explosion; then the mold is heated to a post-curing temperature of 80°C and maintained for 1 hour to improve the conversion rate of the resin reaction, thereby preparing the recyclable resin-based composite material, and its test specimen is prepared by an engraving machine.

[0080] Example 8

[0081] The recycling method of composite materials comprises the following steps:

[0082] 100 g of the composite material prepared in Example 5 was taken and heated to 300° C. in a nitrogen environment and maintained for 1 hour to obtain glass fibers and a resin stock solution.

[0083] Example 9

[0084] The recycling method of composite materials comprises the following steps:

[0085] 100 g of the composite material prepared in Example 6 was taken and heated to 180° C. in a nitrogen environment and maintained for 4 hours to obtain glass fibers and a resin stock solution.

[0086] Example 10

[0087] The recycling method of composite materials comprises the following steps:

[0088] 100 g of the composite material prepared in Example 7 was taken and heated to 400° C. in a nitrogen environment and maintained for 1 hour to obtain glass fibers and a resin stock solution.

[0089] Table 3 Comparison of curing properties of recyclable resin compositions

[0090] Mixing viscosity Shrinkage tensile strength Elongation Heat deformation temperature Example 1 106cP 7.6％ 83MPa 6.7％ 113℃ Example 2 118cP 10.3％ 71MPa 5.3％ 106℃ Example 3 101cP 7.1％ 76MPa 7.1％ 108℃ Example 4 115cP 7.5％ 81MPa 6.3％ 115℃ Comparative Example 1 92cP 14.3％ 56MPa 3.7％ 73℃ Comparative Example 2 96cP 15.9％ 61MPa 2.9％ 86℃ Comparative Example 3 95cP 15.3％ 64MPa 2.3％ 89℃

[0091] Table 4 Comparison of properties of recyclable resin-based composite materials

[0092]

[0093]

[0094] Table 5 Recovery rate of composite fiber and resin

[0095] Example Total mass (glass fiber + resin) Fiberglass Recycling Resin recovery Resin recovery rate 8 67g+33g 65g 30g 91％ 9 86g+14g 85g 13g 93％ 10 80+20g 79g 18g 90％

[0096] It can be seen that the present invention prepares a resin material that is easy to recycle and is superior to the epoxy resin material currently on the market.

Claims

1. A recyclable resin composition for wind turbine blade composite materials, characterized in that: The composition comprises components having the following mass ratios: Wherein, the comonomer R1 is a monomer synthesized from diisocyanate and hydroxy methacrylate; The comonomer R2 is a monomer synthesized from glycidyl methacrylate (GMA) and methacrylate polyethylene glycol ammonium (MAC-PEG-NH2).

2. The composition according to claim 1, wherein The composition comprises components having the following mass ratios:

3. The composition according to claim 1 or 2, wherein The MMA prepolymer is prepared by homopolymerization of MMA monomer.

4. The composition according to claim 1 or 2, wherein The number average molecular weight of the MMA prepolymer is 300-4000.

5. The composition according to claim 1 or 2, wherein The diisocyanate is selected from one or more of diphenylmethane diisocyanate (MDI), dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IPDI), and toluene diisocyanate (TDI); The hydroxy methacrylate is selected from hydroxyethyl methacrylate (HEMA) and / or hydroxypropyl methacrylate (HPMA).

6. The composition according to claim 1 or 2, wherein The preparation method of the comonomer R1 is as follows: diisocyanate and hydroxy methacrylate are mixed and then heated for reaction.

7. The composition according to claim 6, wherein The molar ratio of the diisocyanate to the hydroxy methacrylate is 1:(1-5); The reaction temperature is 25-100° C., and the reaction time is 0.5-10 h.

8. The composition according to claim 7, wherein The molar ratio of the diisocyanate to the hydroxy methacrylate is 1:(2-3); The reaction temperature is 40-80° C., and the reaction time is 1-3 hours.

9. The composition according to claim 1, wherein The preparation method of the comonomer R2 is as follows: glycidyl methacrylate (GMA) and methacrylate polyethylene glycol ammonia system are mixed and then heated to react.

10. The composition according to claim 9, wherein The molar ratio of glycidyl methacrylate (GMA) to polyethylene glycol amine methacrylate is 1:(1-5); The reaction temperature is 25-100° C., and the reaction time is 0.5-10 h.

11. The composition according to claim 1, wherein The catalyst is selected from one or more of cobalt isooctanoate, potassium isooctanoate, copper isooctanoate, and N,N-dimethylaniline.

12. The composition according to claim 1, wherein The initiator is selected from one or more of benzoyl peroxide (BPO), di-tert-butyl peroxide (DTBP), tert-butyl peroxy-2-ethylhexanoate (TBPO), tert-butyl peroxy terephthalate (TBPB), and methyl ethyl ketone peroxide (MEKP).

13. A method for preparing a recyclable resin-based composite material, the method using the recyclable resin composition according to any one of claims 1 to 12, characterized in that: The preparation method comprises the following steps: compounding the above-mentioned recyclable resin composition with fibers and performing heating and curing.

14. The preparation method according to claim 13, wherein The fiber is one or more of glass fiber, carbon fiber, aramid fiber and bamboo fiber.

15. The preparation method according to claim 14, wherein The mass ratio of the recyclable resin composition to the fiber is 1:(2-6).

16. The preparation method according to claim 13, wherein The thermal curing includes pre-curing and post-curing.

17. The preparation method according to claim 16, wherein The pre-curing temperature is 30-50°C and the time is 1-4 hours; The post-curing temperature is 60-100° C., and the curing time is 1-4 hours.

18. The preparation method according to claim 17, wherein The pre-curing temperature is 35-45°C and the time is 2-3 hours; The post-curing temperature is 75-85° C. and the time is 2-3 hours.

19. A recyclable resin-based composite material, prepared by the preparation method according to any one of claims 13 to 18, characterized in that: The thermal degradation temperature of the composite material in a nitrogen atmosphere is 180-400°C.

20. The preparation method according to claim 19, wherein The thermal degradation temperature of the composite material in a nitrogen atmosphere is 250-350°C.

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