A method for preparing wind turbine blade recycled fiber reinforced polyolefin masterbatch

Abstract

The invention discloses a method for preparing a wind turbine blade recycled fiber reinforced polyolefin masterbatch. A method for preparing a wind turbine blade recycled fiber reinforced polyolefin masterbatch comprises the following steps: S1: low temperature plasma treatment of wind turbine blade recycled fiber; S2: preparation of silane coupling agent solution; S3: soaking and aging; S4: drying; S5: low temperature plasma treatment; S6: DCP dissolution; S7: spraying and stirring; S8: dissolving DCP and MAH; S9: spraying DCP and MAH solution in polyolefin; S10: granulation to obtain wind turbine blade recycled fiber reinforced polyolefin masterbatch. The invention is conducive to overcoming the defects of the prior art that the wind turbine blade recycled fiber cannot be well utilized and the performance is insufficient when preparing composite materials.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material manufacturing and relates to a method for preparing a wind turbine blade recycled fiber reinforced polyolefin masterbatch. Background Art

[0002] China's wind power industry is developing rapidly and is about to face the challenge of large-scale wind turbine blade retirement. The harmless treatment, high-value utilization and resource utilization of discarded wind turbine blades have become key issues for the sustainable development of the wind power industry. At present, the main components of retired wind turbine blades are epoxy resin and glass fiber, and they also contain a small amount of metal, balsa wood and foam. However, since epoxy resin is a thermosetting material, it is difficult to recycle and reuse. Globally, the main recycling technologies for discarded wind turbine blades include physical recycling, thermal recycling and chemical recycling. Thermal recycling equipment is expensive and easily produces toxic and harmful waste gas; chemical recycling has high energy consumption and large solvent usage. Therefore, these technologies are difficult to achieve industrialization, while physical recycling has greater industrialization potential. However, due to the limitations of the recycling process, currently only cured epoxy resin powder and glass fiber short fibers containing cured epoxy resin (purity 60-90%) can be obtained through cutting, crushing, grinding and other methods, and the resulting materials can often only be used for low-value materials. This limits the application areas and performance of recycled materials, greatly affects how to achieve harmless and high-value utilization of discarded wind turbine blades, and has a significant impact on the sustainable development of the wind power industry.

[0003] On the other hand, polyolefins are a general-purpose plastic that is widely used in daily life. In order to improve the strength of polyolefins, glass fibers are usually added to plastics. However, the fiber components in recycled wind turbine blades are impure, and there are many defects in the materials during the mechanical recycling process, which leads to poor reinforcement effect of recycled fibers on polyolefins, thus hindering its industrial application. Therefore, how to modify the materials and improve the processes of discarded wind turbine blades to significantly improve the performance of composite materials and apply them to higher-end fields has become a key issue in whether discarded wind turbine blades can achieve high-value applications.

[0004] There is a lack of relevant technology in the existing technology as a reference. It is necessary to propose a new technical solution to solve the problem of resource utilization of discarded wind turbine blades and contribute to the sustainable development of the wind power industry. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a method for preparing a wind turbine blade recycled fiber reinforced polyolefin masterbatch that overcomes the defects of existing materials, has a more reasonable process, has better product performance, and can effectively utilize wind turbine blade recycled fibers.

[0006] The technical solution adopted by the present invention is:

[0007] A method for preparing a wind turbine blade recycled fiber reinforced polyolefin masterbatch, comprising the following steps: S1: modifying the wind turbine blade recycled fiber by a low-temperature plasma treatment process to obtain a material A; S2: preparing anhydrous ethanol and distilled water into a solution B, adding a silane coupling agent into the solution B to obtain a solution C; S3: placing the material A in the solution C, soaking the material A in the solution C, and subjecting the material A to an aging process;

[0008] S4: further placing the material treated in step S3 in a drying device to dry to obtain material D; S5: modifying the material D by a low-temperature plasma treatment process to obtain material E; S6: dissolving DCP in an acetone solution to obtain a solution F; S7: spraying the solution F on the material E, stirring evenly, to obtain material G; S8: dissolving DCP and MAH in an acetone solution to obtain a solution H; S9: spraying the solution H on polyolefin, stirring evenly, to obtain material I; S10: granulating the material G and the material I in a granulator to obtain a wind turbine blade recycled fiber reinforced polyolefin masterbatch J.

[0009] As a further improvement of the above method, the wind turbine blade recycled fiber in step S1 is a mechanically processed recycling product of discarded wind turbine blades, and the mechanical processing includes one or more of a cutting step, an impact step, a tearing step, an extrusion step, a hammering step, a grinding step, and a screening step.

[0010] As a further improvement of the above method, the wind turbine blade recycled fiber in step S1 includes 60-90 parts by mass of glass fiber and 10-40 parts by mass of cured epoxy resin powder, and the epoxy resin powder is irregularly distributed and attached to the surface of the glass fiber.

[0011] As a further improvement of the above method, the silane coupling agent in step S2 is one or more silane coupling agents with amino functional groups or vinyl functional groups.

[0012] As a further improvement of the above method, the silane coupling agent is KH550 silane coupling agent and / or KH151 silane coupling agent.

[0013] As a further improvement of the above method, the mass ratio of DCP contained in the solution F in step S7 to the mass ratio of material E is less than 1:100.

[0014] As a further improvement of the above method, the mass ratio of DCP contained in the solution H of step S9 to the mass ratio of polyolefin is in the range of 1:1000 to 1:100; the mass ratio of MAH contained in the solution H of step S9 to the mass ratio of polyolefin is in the range of 1:200 to 1:20.

[0015] As a further improvement of the above method, the granulator in step S10 has a main barrel, the main barrel has a main feeding port, the granulator also has a side feeder and a die, one or more barrel sections are provided between the main feeding port of the main barrel and the side feeder, one or more barrel sections are provided between the side feeder and the die, and one or more ultrasonic devices are provided on the barrel section.

[0016] As a further improvement of the above method, the material G is fed by the side feeder.

[0017] As a further improvement of the above method, the granulator in step S10 has a main barrel, the main barrel has a main feeding port, the granulator also has a side feeder and a die, a plurality of barrel sections are provided between the side feeder and the die, and one or more ultrasonic devices are provided on the barrel section between the side feeder and the die.

[0018] As a further improvement of the above method, the granulator is a parallel twin-screw granulator.

[0019] As a further improvement of the above method, in step S10, the mass ratio of material G to material I is between 1:9 and 9:1.

[0020] The beneficial effects of the present invention are:

[0021] 1. During the curing process of epoxy resin, due to the participation of a large number of active groups such as hydroxyl and epoxy groups in the reaction, the active groups of the cured epoxy resin are relatively few. In order to achieve a good interface bonding between the cured epoxy resin and the polyolefin, the present invention can increase a large number of active groups such as hydroxyl, carbonyl, and carboxyl groups on the surface of the epoxy resin attached to the recycled fiber by treating the recycled fiber with low-temperature plasma. These active groups can chemically react or hydrogen bond with silane coupling agents and maleic anhydride grafted polyolefins. At the same time, the surface of the epoxy resin will be etched to form grooves, thereby increasing the specific surface area and further improving the adhesion.

[0022] 2. In the process of recycling discarded wind turbine blades, some epoxy resins are peeled off from the surface of glass fibers after mechanical actions such as crushing and grinding. Although other epoxy resins adhere to the surface of glass fibers, the mechanical action leads to serious interface damage and connection weaknesses. These situations will greatly lead to more defects in the prepared composite materials, and their mechanical properties will decrease. The existing fiber recycling and reuse technology field still lacks effective methods to solve this problem. The present invention can effectively enhance the adhesion between the recycled fibers and the composite matrix, thereby improving the structural strength and durability of the composite material, helping to overcome the interface damage and connection weaknesses that occur during the recycling process, and helping to prepare higher performance composite materials.

[0023] 3. After the coupling agent KH550 and / or KH151 is used to treat the recycled fibers of discarded wind turbine blades in the present invention, the coupling agent will generate silanol during the hydrolysis process, and then react with the glass fiber of the recycled fiber and the hydroxyl groups on the surface of the cured epoxy resin to form a silicon-oxygen covalent bond. Through such treatment, on the one hand, the interface bonding between the glass fiber and the cured epoxy resin can be improved; on the other hand, the amino group in the KH550 silane coupling agent can react with the maleic anhydride group on the polyolefin molecular chain, and the vinyl group in the KH151 coupling agent can react with the polyolefin molecular chain under the action of DCP. These reactions can further improve the interface bonding between the glass fiber, the cured epoxy resin and the polyolefin, and improve the performance of the composite material.

[0024] 4. After being treated with the silane coupling agent, most of the hydroxyl groups of the epoxy resin on the recycled fiber have reacted with the silane coupling agent. In order to further improve the interfacial properties of the material, the present invention provides multiple low-temperature plasma treatment steps. Such treatment can introduce more active groups such as hydroxyl groups and carboxyl groups on the surface of the epoxy resin, thereby increasing the chance and probability of chemical reaction with the maleic anhydride grafted polyolefin. Through this treatment method, the present invention can make the chemical reaction between the recycled fiber and the composite material matrix more sufficient, further increase the probability of chemical interaction between the recycled fiber and the polymer matrix, enhance its interfacial bonding ability, and improve the bonding strength and stability of the interface.

[0025] 5. In order to ensure that the vinyl group in KH151 can react chemically with polyolefin quickly, the present invention fully considers the problem of premature consumption of DCP in material I due to in-situ grafting reaction. By adding an appropriate amount of DCP to material E to generate more free radicals, the vinyl group in KH151 can be effectively combined with polyolefin. This measure can improve the reaction efficiency and increase the interface bonding of the product.

[0026] 6. The present invention grafts maleic anhydride groups onto the surface of polyolefin through an in-situ grafting reaction of DCP and MAH.

[0027] 7. It is generally believed that ultrasound has little effect on the preparation process of composite materials, but in the present invention, the ultrasonic device installed between the main feed port of the granulator and the side feeder can improve the chemical reaction process of polyolefins. Under the vibration of ultrasound, the free radical content is increased, which promotes the movement of polyolefin molecular chains. In this way, more maleic anhydride (MAH) can be successfully grafted onto the polyolefin molecular chain under the influence of the present invention, thereby improving the in-situ grafting rate.

[0028] 8. The present invention sets an ultrasonic device between the side feeder and the granulator die. Ultrasonic vibration increases the free radical content, accelerates the movement of the polyolefin molecular chain, makes the vinyl functional group on the KH151 coupling agent and the polyolefin have more covalent bonds, and increases the probability of the amino functional group of KH550 and the maleic anhydride group on the in-situ grafted polyolefin to react, forming more amide covalent bonds, resulting in a significant increase in the reaction contact points of the epoxy resin, glass fiber and polyolefin molecular chain, thereby greatly improving the interfacial compatibility of the above three components. In addition, ultrasonic vibration helps disperse the glass fiber and reduce the probability of glass fiber agglomeration, so that the function of fiber-reinforced thermoplastic resin can be better exerted.

[0029] 9. When there is no side feeder, the process is simpler and the quality is easier to control. Moreover, after the material G and the material I are mixed, the dispersion of the recycled fiber in the polyolefin is more uniform.

[0030] In summary, through low-temperature plasma and silane coupling agent modification treatment, the active groups in the recycled fibers of wind turbine blades are greatly increased. Through in-situ grafting modification and ultrasonic vibration, the interfacial compatibility of glass fiber, cured epoxy resin and polyolefin in the recycled fibers of wind turbine blades is greatly improved, and the dispersibility of recycled fibers in polyolefins is improved. Thus, the recycled fiber reinforced polyolefin masterbatch of wind turbine blades is prepared, so that the recycled waste wind turbine blades can be utilized in a high value manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a schematic flow chart of a method for preparing a wind turbine blade recycled fiber reinforced polyolefin masterbatch. DETAILED DESCRIPTION

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the embodiments are briefly described below. Obviously, what is described is only a part of the embodiments of the present invention, not all of them, and those skilled in the art can also obtain other design solutions based on the flow chart without creative work.

[0033] A method for preparing a wind turbine blade recycled fiber reinforced polyolefin masterbatch comprises the following steps: S1: modifying the wind turbine blade recycled fiber by a low-temperature plasma treatment process to obtain a material A; S2: preparing a solution B by mixing anhydrous ethanol and distilled water, and adding a silane coupling agent to the solution B to obtain a solution C; S3: placing the material A in the solution C, soaking the material A in the solution C, and subjecting the material A to an aging process; S4: further placing the material treated in step S3 in a drying device for drying to obtain a material D; S5: The material D is modified by low temperature plasma treatment process to obtain material E; S6: DCP is placed in acetone solution for dissolution to obtain solution F; S7: the solution F is sprayed on the material E, stirred evenly, to obtain material G; S8: DCP and MAH are dissolved in acetone solution to obtain solution H; S9: the solution H is sprayed on polyolefin, stirred evenly, to obtain material I; S10: the material G and the material I are granulated by a granulator to obtain wind turbine blade recycled fiber reinforced polyolefin masterbatch J. The beneficial effects of this embodiment are: providing a more reasonable composite material manufacturing process, which is conducive to overcoming the defects of the existing technology that the cured epoxy resin powder and the glass fiber short fiber containing the cured epoxy resin are insufficient in performance when used to prepare composite materials, and the composite product performance can be made better, and a preparation method of wind turbine blade recycled fiber reinforced polyolefin masterbatch that can effectively utilize wind turbine blade recycled fiber is provided.

[0034] As a further improvement of the above method, the wind turbine blade recycled fiber in step S1 is made of discarded wind turbine blades through mechanical processing such as cutting, crushing, grinding, and screening. The wind turbine blade recycled fiber is mainly composed of 60-90 parts by mass of glass fiber and 10-40 parts by mass of cured epoxy resin powder, and the epoxy resin powder is irregularly distributed and attached to the surface of the glass fiber. The beneficial effect of this embodiment is that when the epoxy resin is cured, a large number of active groups such as hydroxyl groups and epoxy groups participate in the reaction, so the active groups of the cured epoxy resin are relatively small. In order to allow the cured epoxy resin and polyolefin to form a good interface bond, the recycled fiber is treated with low-temperature plasma, so that a large number of active groups such as hydroxyl groups are added to the surface of the epoxy resin to which the recycled fiber is attached, which can react chemically with silane coupling agents and maleic anhydride grafted polyolefins. At the same time, the surface of the epoxy resin is etched to form grooves, which increases the specific surface area and improves adhesion.

[0035] As a further improvement of the above method, the silane coupling agent in step S2 is one or more of silane coupling agents with amino functional groups or vinyl functional groups, and the silane coupling agent is KH550 silane coupling agent and / or KH151 silane coupling agent. The beneficial effect of this embodiment is that in the process of recycling discarded wind turbine blades, after mechanical actions such as crushing and grinding, part of the epoxy resin peels off from the surface of the glass fiber, and although part of the epoxy resin is bonded to the surface of the glass fiber, the mechanical action causes serious damage to the interface between the epoxy resin and the glass fiber, and there are many connection weaknesses. This will lead to an increase in defects in the prepared composite material and a decrease in mechanical properties. KH550 and KH151 coupling agents are hydrolyzed into silanols, which react with the hydroxyl groups on the surface of glass fiber and epoxy resin of recycled fibers from discarded wind turbine blades to form silicon-oxygen covalent bonds. On the one hand, this can improve the interfacial bonding between glass fiber and epoxy resin. On the other hand, the amino group of KH550 silane coupling agent can react with the maleic anhydride group on the polyolefin molecular chain, and the vinyl group of KH151 coupling agent can react with polyolefin, thereby improving the interfacial bonding between glass fiber, epoxy resin and polyolefin.

[0036] As a further improvement of the above method, the material D in step S5 is modified by a low-temperature plasma treatment machine for powder to obtain material E. The beneficial effect of this embodiment is that after the recycled fiber is treated with a silane coupling agent, most of the hydroxyl groups of the epoxy resin on it react with the silane coupling agent. The low-temperature plasma treatment is performed again to increase active groups such as hydroxyl groups and carboxyl groups on the surface of the epoxy resin, thereby increasing the probability of chemical reaction with the maleic anhydride grafted polyolefin.

[0037] As a further improvement of the above method, the mass fraction of DCP in the material E in step S7 is 0.1%-1%. The beneficial effect of this embodiment is that the material I first undergoes an in-situ grafting reaction, and the DCP in the material I may be consumed prematurely, while DCP is added to the material E to generate free radicals, which can ensure that the vinyl group of KH151 can react chemically with the polyolefin.

[0038] As a further improvement of the above method, the mass fraction of DCP in the solution H of step S9 is 0.1%-1% of the polyolefin, and the mass fraction of MAH in the polyolefin is 0.5%-5%, and the polyolefin is one or both of PE and PP. The beneficial effect of this embodiment is that maleic anhydride groups are grafted on the surface of the polyolefin through the in-situ grafting reaction of DCP and MAH.

[0039] As a further improvement of the above method, the granulator in step S10 is a parallel twin-screw granulator, the main barrel of the granulator is connected to a side feeder, one or more ultrasonic devices are set at each barrel between the main feed port of the granulator and the side feeder, and one or more ultrasonic devices are set at each barrel between the side feeder and the granulator die. Material G with a mass fraction of 10%-90% is put into the side feeder, and material I with a mass fraction of 10%-90% is put into the main feed port of the granulator, and the wind turbine blade recycled fiber reinforced polyolefin masterbatch J is obtained by reaction extrusion modification of the granulator. The beneficial effect of this embodiment is that an ultrasonic device is set between the main feed port of the granulator and the side feeder, and ultrasonic vibration increases the free radical content, accelerates the movement of polyolefin molecular chains, so that more MAH is grafted onto the polyolefin molecular chains, and the in-situ grafting rate is improved.

[0040] As a further improvement of the above method, an ultrasonic device is arranged between the side feed and the die to prevent the DCP initiator of the maleic anhydride and polyolefin materials from being consumed prematurely, so as to better promote the decomposition of DCP in the recycled fiber and initiate the KH151 vinyl polyolefin reaction.

[0041] As a further improvement of the above method, the granulator in step S10 has a main barrel, the main barrel has a main feed port, the granulator also has a side feeder and a die, a plurality of barrel sections are provided between the side feeder and the die, one or more ultrasonic devices are provided on the barrel section between the side feeder and the die, and the granulator is a parallel twin-screw granulator. The beneficial effects of this embodiment are: ultrasonic vibration increases the free radical content, accelerates the movement of polyolefin molecular chains, makes the vinyl functional groups on the KH151 coupling agent and the polyolefin undergo more covalent bonds, the amino functional groups of KH550 and the maleic anhydride groups on the in-situ grafted polyolefin react with each other with higher probability, and form more amide covalent bonds, resulting in a significant increase in the reaction contact points of the epoxy resin, glass fiber and polyolefin molecular chains, thereby greatly improving the interfacial compatibility of the above three components. In addition, ultrasonic vibration helps disperse the glass fiber and reduces the probability of glass fiber agglomeration, thereby better playing the role of fiber-reinforced thermoplastic resin.

[0042] As a further improvement of the above method, one or more ultrasonic devices are arranged at each barrel of the granulator in step S10. Material G with a mass fraction of 10%-90% and material I with a mass fraction of 10%-90% are mixed evenly, and then the wind turbine blade recycled fiber reinforced polyolefin masterbatch J is obtained by reaction extrusion modification in the granulator. The beneficial effects of this embodiment are: since there is no side feeder, the process is simpler, the quality is easier to control, and after the mixing process of material G and material I, the dispersion of the recycled fiber in the polyolefin is more uniform.

[0043] The present invention uses low-temperature plasma and silane coupling agent modification treatment to greatly increase the active groups in the wind turbine blade recycled fiber, and through in-situ grafting modification and ultrasonic vibration, greatly improves the interface compatibility of glass fiber, cured epoxy resin and polyolefin in the wind turbine blade recycled fiber, improves the dispersibility of the recycled fiber in polyolefin, thereby preparing wind turbine blade recycled fiber reinforced polyolefin masterbatch, so that the recycled waste wind turbine blades can be used in a high-value manner.

Claims

1. A method for preparing a wind turbine blade recycled fiber reinforced polyolefin masterbatch, comprising the following steps: S1: Modifying the recycled fiber from wind turbine blades by low-temperature plasma treatment to obtain material A; S2: Anhydrous ethanol and distilled water are mixed to form solution B, and a silane coupling agent is added to solution B to prepare solution C; S3: placing the material A in the solution C, allowing the material A to be immersed in the solution C, and undergoing an aging process; S4: the material processed in step S3 is further placed in a drying device for drying to obtain material D; S5: modifying the material D by a low-temperature plasma treatment process to obtain a material E; S6: dissolving DCP in an acetone solution to obtain a solution F; S7: Spray the solution F into the material E and stir evenly to obtain material G; S8: dissolving DCP and MAH in an acetone solution to obtain a solution H; S9: spraying the solution H into the polyolefin and stirring evenly to obtain material I; S10: Granulating the material G and the material I with a granulator to obtain a wind turbine blade recycled fiber reinforced polyolefin masterbatch J; In step S1, the wind turbine blade recycled fibers include 60-90 parts by mass of glass fibers and 10-40 parts by mass of cured epoxy resin powder, and the epoxy resin powder is irregularly distributed and attached to the surface of the glass fibers; The silane coupling agent in step S2 is a silane coupling agent with an amino functional group, specifically a KH550 silane coupling agent, and the silane coupling agent with a vinyl functional group, specifically a KH151 silane coupling agent; The mass ratio of DCP contained in the solution F of step S7 to the mass ratio of material E is less than 1:100; The mass ratio of DCP contained in the solution H of step S9 to the mass ratio of polyolefin is in the range of 1:1000 to 1:100; the mass ratio of MAH contained in the solution H of step S9 to the mass ratio of polyolefin is in the range of 1:200 to 1:

20.

2. The method for preparing a wind turbine blade recycled fiber reinforced polyolefin masterbatch according to claim 1, characterized in that: The wind turbine blade recycled fiber in step S1 is a mechanically processed recycling product of discarded wind turbine blades, and the mechanical processing includes one or more of a cutting step, an impact step, a tearing step, an extrusion step, a hammering step, a grinding step, and a screening step.

3. The method for preparing a wind turbine blade recycled fiber reinforced polyolefin masterbatch according to claim 1 or 2, characterized in that: In the step S10, the granulator comprises a main barrel, the main barrel has a main feeding port, the granulator also comprises a side feeder and a die, one or more barrel sections are arranged between the main feeding port of the main barrel and the side feeder, one or more barrel sections are arranged between the side feeder and the die, and one or more ultrasonic devices are arranged on the barrel section; the material G is fed by the side feeder.

4. The method for preparing a wind turbine blade recycled fiber reinforced polyolefin masterbatch according to claim 3, characterized in that: In step S10, the mass ratio of material G to material I is between 1:9 and 9:1.

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