Method for producing packaging box by using old wind power blade

Abstract

The embodiment of the invention discloses a method for producing a packaging box from old wind power blades, which specifically comprises the following steps of: 1, recycling the wind power blades, and sorting short glass fibers and glass fiber reinforced plastic particles; 2, preparing glass fiber reinforced particles from the short glass fibers and the thermoplastic base material through a hot extrusion process; 3, preparing glass fiber reinforced plastic filling master batch from the glass fiber reinforced plastic particles and a thermoplastic base material through a hot extrusion process; 4, the glass fiber reinforced particles, the glass fiber reinforced plastic filling master batch and the thermoplastic base material are used for producing the packaging box through a mold pressing technology; according to the method for producing the packaging box through the old wind power blade, ecological recovery and ecological application can be achieved, due to the adding and modifying effects of the glass fiber reinforced particles and the glass fiber reinforced plastic filling master batch, various structural types are adopted for all components of the packaging box, and the packaging box has the advantages of being high in structural strength, resistant to deformation and low in water absorption amount.

Description

Technical Field

[0001] The invention relates to the field of material recycling, and in particular to a method for producing packaging boxes for used wind turbine blades. Background Art

[0002] At present, wind turbines are electrical equipment that converts wind energy into mechanical work, which drives the rotor to rotate and finally outputs alternating current. Wind turbines include blades, nacelle covers, fairings and other parts, which contain a large amount of fiberglass. The so-called fiberglass (Glass Fiber Reinforced Plastic, referred to as GFRP) refers to fiberglass reinforced plastic or carbon fiber reinforced plastic made of epoxy resin, unsaturated resin, etc. infiltrated with glass fibers or carbon fibers of different lengths.

[0003] More than 140,000 wind turbines have been installed in service, with more than 100 million kilowatts of wind turbines connected to the grid for more than five years, accounting for 46.1% of the total grid-connected capacity. The total capacity of wind turbines in service for more than 20 years is about 381,000 kilowatts, mainly concentrated in the "Three Norths" region. It is expected that there will be a peak in the retirement and recycling of a large number of units.

[0004] Normally, the design life of wind turbine blades is 20 years, and most wind farms begin to gradually retire after 15 years. Currently, blades from old wind farms have begun to be retired one after another. By the end of 2019, the number of blades on the wind turbines exceeded 135,000 sets. According to incomplete statistics, about 5,700 tons of blades were retired in 2018, and about 10,000 to 15,000 tons of blades were retired in 2021. In the future, the number of retired blades will increase exponentially.

[0005] At present, there are three most mature methods for the disposal of retired wind turbine blades. The first is to crush them and add them to the construction industry for non-critical components to replace cheap sand and gravel materials; the second is to cut the flat part of the blade and make it into packaging or decorations for sale; the third is to dispose of them in cement kilns or incinerate them in power plants. None of the above methods can solve the problem of resource reuse of scrapped wind turbine blades.

[0006] Most of the existing packaging boxes are made of paper, and the production of paper packaging boxes consumes a lot of forest resources and water resources; and the number of times they can be reused is too small (that is, the cost of each use is high); on the other hand, there are reusable boxes produced with PP as raw material. This box is made of a single PP material, with high manufacturing cost, high hardness and heavy weight; it relies on hinges to flip and fold into pieces, with too many spare parts, resulting in cumbersome assembly, and there are gaps at each corner. Due to the single material, the functional characteristics of each part of the box cannot be fully guaranteed, such as the wear resistance and water resistance of the box board, and the toughness of the bending part, and the damage rate is high.

[0007] In summary, there is a huge demand for better recycling and reuse of wind turbine blade fiberglass and processing and producing suitable molding application products. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention provides a method for producing packaging boxes for used wind turbine blades, wherein the recycled wind turbine blades are processed and sorted, and different components are applied to the packaging box molding preparation process. The method is characterized in that the resource recovery and further utilization of wind turbine blades can be achieved.

[0009] A method for producing a packaging box for used wind turbine blades, characterized in that it comprises the following steps:

[0010] Step 1: Recycle the wind turbine blades and sort out short glass fibers and glass fiber reinforced plastic particles;

[0011] Step 2: short glass fibers and thermoplastic substrates are subjected to a hot extrusion process to prepare glass fiber reinforced particles;

[0012] Step 3, preparing a FRP filler masterbatch by hot extrusion of FRP particles and thermoplastic substrate;

[0013] Step 4: Use glass fiber reinforced particles, FRP filler masterbatch and thermoplastic substrate through a molding process to produce packaging boxes.

[0014] A method for producing a packaging box for used wind turbine blades, characterized in that it comprises the following steps:

[0015] Step 1: Recycle the wind turbine blades and sort out short glass fibers and glass fiber reinforced plastic particles;

[0016] Step 2, modifying the surface of the short glass fiber;

[0017] Step 3, the FRP particles are further crushed to produce FRP powder;

[0018] Step 4: Use short glass fibers, glass fiber reinforced plastic powder and thermoplastic substrates to produce packaging boxes through extrusion, blow molding and injection molding processes.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] Energy saving and environmental protection, realizing resource recovery and further utilization of wind turbine blades, can realize ecological recycling and ecological application. The present invention pioneers the use of wind turbine blades in packaging boxes. From the perspective of product application, it can save energy and effectively turn waste into treasure. Due to the added modification effect of glass fiber reinforced particles and glass fiber reinforced plastic filling masterbatch, the various components of the packaging box adopt a variety of structural types, and each component adopts layered and partitioned fabrics, which can provide different material properties in different areas. The overall packaging box has the advantages of high structural strength, anti-deformation, and low water absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 For process Figure 1 ;

[0022] Figure 2 This is a schematic diagram of the flat expansion of the packaging box;

[0023] Figure 3 It is a three-dimensional schematic diagram of the packaging box;

[0024] Figure 4 It is a schematic diagram of the cross section of the lower die of the mold along the AA direction;

[0025] Figure 5 This is a schematic diagram of loading material into the AA section of the lower die of the mold;

[0026] Figure 6 For process Figure 2 .

[0027] Numbers in the figure: 1 panel area, 2 bending connection area, 3 main mold cavity, 11, sub-mold cavity, 31 main mold cavity middle layer, 33 main mold cavity top layer, 111 sub-mold cavity bottom layer, 113 sub-mold cavity middle layer. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] (I) Wind turbine blade recycling process

[0030] (1) Pretreatment and preparation of wind turbine blades

[0031] The root of a wind turbine blade is 7 to 18 cm thick, the load-bearing main beam is generally longer than 40 meters, and the Mohs hardness is extremely high. Special blade cutting tools can be used to cut and dismember retired wind turbine blades into blocks of 0.8m to 1m square, and the cutting and dismembering process can be completed on site at the wind farm;

[0032] The retired wind turbine blades are dismembered into blocks at the wind farm site. They do not need to be sorted after entering the factory and are temporarily stored in the raw material area. When loading the production line, the block-shaped retired wind turbine blades are transported from the raw material area to the conveyor, which then transports them to the crusher hopper.

[0033] (2) Coarse crushing of wind turbine blades

[0034] Due to the high hardness, strong toughness and high specific gravity of the blade material, it is very difficult to process the blade material. Currently, there is no perfect processing method and equipment to process it into block materials not exceeding 5 cm.

[0035] The coarse crushing process uses a specially developed FRP crusher to crush the dismembered blocks, which can be crushed into block materials with a particle size of 2cm-5cm.

[0036] The main body of the FRP special crusher adopts a hammer crushing mechanism. In order to adapt to the material characteristics of wind turbine blades, the hammer in the hammer crushing mechanism has an improved hammer head structure. The hammer head is a hexahedron, the bottom of the hammer head is fixedly connected to the hammer handle, and the top of the hammer head is provided with a friction working surface, and the friction working surface is processed with a friction mesh. The improved FRP special crusher has two crushing effects: extrusion and shearing. The hammer of the hammer crushing mechanism rotates and impacts to generate an extrusion impact force, which first squeezes and crushes the wind turbine blades; and the friction working surface of the hammer will produce a friction shearing effect on the wind turbine blades, further producing a fine crushing effect. Under the heavy load extrusion stress of the hammer crushing mechanism, the hollow structure of the wind turbine blade first destroys the bonding structure between the thermosetting resin and the reinforced glass fiber to obtain a higher crushing efficiency; then, through the friction shearing effect, the slender reinforced glass fiber in the wind turbine blade fragments is cut off, which promotes the effective separation of the thermosetting resin particles and the slender reinforced glass fiber.

[0037] The material is crushed into 2cm blocks using a special FRP crusher. The crushed material is directly conveyed by a conveyor to the primary screening machine for screening. The dust generated in the crushing process is collected by negative pressure in a closed compartment, introduced into a bag dust collector for treatment, and then discharged through an exhaust pipe.

[0038] (3) Primary screening of materials

[0039] The proportions of PVC, balsa wood and fiberglass in wind turbine blades are 5%, 5% and 90% respectively. After coarse crushing, the three material components of PVC, balsa wood and fiberglass can be separated.

[0040] According to the difference in specific gravity of the three material components, the first screening machine is used for separation. The coarsely crushed materials enter the first screening machine to separate PVC, balsa wood and fiberglass.

[0041] The first screening machine uses an airflow separator. After the block material enters the airflow separator, it is simultaneously subjected to the combined effects of mechanical vibration and rising airflow. According to the physical properties of different materials, different materials will be regularly sorted and moved according to their specific gravity and shape. The heavy fiberglass debris moves downward and is discharged from the lower discharge port; the light PVC particles move upward and are discharged from the higher discharge port, and the lighter lightweight balsa wood material particles flow away from the upper airflow port with the rising airflow, thereby separating PVC, balsa wood, and fiberglass. Specifically, the fiberglass debris will flow out from the lower outlet of the airflow separator, and PVC will flow out from the upper outlet of the airflow separator. The balsa wood particles will be sucked into the cyclone separator under the action of the negative pressure airflow above the airflow separator, and discharged from the bottom of the cyclone separator.

[0042] The three separated materials, PVC, balsa wood and fiberglass, enter the corresponding storage bins respectively. The separated PVC and balsa wood can be packaged and shipped as finished products. The dust generated in the primary screening process is collected by negative pressure in a closed compartment, introduced into a bag filter for treatment, and then discharged through an exhaust pipe.

[0043] (4) Fine crushing of FRP debris

[0044] The FRP debris after primary screening can be transported by a conveyor to a fine crusher for further crushing, and finally crushed into granular materials with a particle size of 1 cm.

[0045] The crushing mechanism of the fine crusher includes a wear-resistant lining installed on the inner wall of the machine body. Two left and right bearing seats are installed on the outer wall of the machine body, and a rotating main shaft installed in the two bearing seats is installed on it. A tool holder is installed on it, and a hammer is installed on the tool holder; a balance flywheel is installed at one end of the main shaft, and a pulley is installed at the other end of the main shaft. The pulley on the main shaft is connected to the pulley at the motor end through a belt. When the motor rotates at high speed, it drives the main shaft to rotate at high speed through the pulley and belt, and then drives the tool holder and the hammer on the tool holder to rotate at high speed, and then knocks the material entering the machine cavity at high speed, so that the material is driven by the impact of the hammer and continuously hits the wear-resistant lining on the inner wall of the machine body, and finally achieves the purpose of crushing the material. The crushed material reaches the machine discharge port through the discharge screen at the bottom of the cavity.

[0046] The material in the fine crusher is the glass fiber reinforced plastic debris after coarse crushing. The fine crushing is achieved by the hammer head rotating at high speed and continuously impacting with the wear-resistant lining on the inner wall of the machine body. The crushed material is directly transported by the conveyor to the second screening machine for screening. The dust generated in the crushing process is collected by the negative pressure in the closed compartment, introduced into the bag dust collector for treatment, and then discharged through the exhaust pipe.

[0047] In the FRP fine crushing stage, pre-treated FRP debris from other sources can also be added from the outside in parallel. The pre-treated FRP debris from other sources only needs to meet the feed size conditions of the fine crushing process.

[0048] (5) Secondary screening of materials

[0049] The ratio of glass fiber and FRP particles (resin) in FRP is 50% and 50% respectively. According to the difference in specific gravity of the components, a screening machine is used for separation. The finely crushed material enters the second screening machine to separate the glass fiber and FRP particles.

[0050] The second screening machine can be a vibrating screening machine. When in use, the motor drives the filter screen to swing and vibrate back and forth through the driving mechanism, so that the finely crushed materials fall into the filter screen for classification and filtration. The glass fiber is crushed into short glass fibers of smaller length, which are discharged through the glass fiber outlet after passing through the filter screen, and the larger glass fiber reinforced plastic particles are collected on the filter screen and fall through the glass fiber reinforced plastic particle outlet. The filter screen has an inclined surface, and the filter screen uses the inclined surface and vibration to automatically vibrate and roll the falling crushed residue, thereby accelerating the efficiency of classification.

[0051] The separated glass fiber and FRP particles enter the corresponding storage bins respectively. After the glass fiber is separated from the resin components through the coarse and fine crushing process, its length is relatively short (<2mm). As short glass fiber, it can be used to produce glass fiber reinforced particles. The FRP particles are further ground and processed to produce resin filling masterbatch. The dust generated in the screening process is collected by negative pressure in a closed compartment, introduced into the bag dust collector for treatment, and then discharged through the exhaust pipe.

[0052] (II) Glass fiber reinforced particle process

[0053] (1) Loading and mixing

[0054] A. Short glass fiber surface treatment.

[0055] Method 1:

[0056] The separated glass fibers are dried and cleaned. The short glass fibers obtained after screening are poured into a high-speed mixer and stirred at high speed. When the material temperature rises to 100°C, a coupling agent is added for surface treatment. The treated short glass fibers are cooled and packaged for later use.

[0057] The silane coupling agent and industrial alcohol are mixed at a volume ratio of 1-5:5-10 at room temperature for 20-30 minutes to obtain a silane coupling agent after alcoholysis; the silane coupling agent is γ-aminopropyltriethoxysilane;

[0058] The alcoholyzed silane coupling agent is mixed with the short glass fiber and then stirred to obtain the surface-treated short glass fiber; the weight ratio of the alcoholyzed silane coupling agent to the short glass fiber is 1-5:95-99, the stirring time is 10-30 minutes, the speed is 1300-2000 rpm / min, and the equipment used is a high-speed stirrer;

[0059] The solvents selected were isopropanol and ethanol.

[0060] Method 2:

[0061] Due to the recycling of old materials, if the short glass fibers obtained after the original screening are mixed with a lot of dust, they need to be cleaned on the surface first. The short glass fibers obtained after screening are treated with water and soaked and cleaned in a water tank. The water tank has a filter for placing the short glass fibers to be cleaned to prevent the loss of short glass fibers during soaking and cleaning. After the surface cleaning of the short glass fibers is filtered and left to stand for 1-2 hours, the water content is reduced to a qualified level. The modified surface treatment can be carried out.

[0062] The titanate coupling agent and liquid paraffin are mixed at a volume ratio of 1 to 5:5 at room temperature for 20 to 30 minutes to obtain a diluted titanate coupling agent; the titanate coupling agent is a chelated phosphate titanium coupling agent quaternary ammonium salt; the titanate coupling agent TC-WT is purchased from Tianchang Tianchen Chemical Additive Oil Plant.

[0063] Its chemical formula is

[0064] The diluted titanate coupling agent is mixed with the water-treated short glass fiber and then stirred to obtain a modified surface-treated short glass fiber; the weight ratio of the diluted titanate coupling agent to the short glass fiber is 1-3:97-99, the stirring time is 10-20 minutes, the speed is 1300-2000 rpm / min, and the equipment used is a high-speed mixer;

[0065] The solvent may be liquid paraffin (i.e. white oil), solvent oil or water.

[0066] After modified surface treatment, short glass fibers are easier to disperse evenly in the matrix and provide good coupling between inorganic short glass fibers and polymer systems. Short glass fibers are less than 2 mm in length and disperse evenly in the matrix without any directionality, which can better overcome the anisotropy problem that is easily generated by adding glass fibers to polymer products, and the excellent coupling combination is conducive to improving the structural strength of the product.

[0067] B. Mix the base material components in appropriate proportions.

[0068] After weighing polypropylene (PP), dispersant, antioxidant and lubricant respectively, pour them into a high-speed mixer for stirring.

[0069] a. First, pour 100 kg of polypropylene into a high-speed mixer at a speed of 900 rpm and stir for later use.

[0070] b. Pour 10 kg of dispersant maleic anhydride grafted polypropylene, 1 kg of antioxidant 1010, 1 kg of antioxidant 168, and 4 kg of lubricant stearic acid into a high-speed mixer at a speed of 900 rpm and mix until the friction heat generated by the mixing raises the material temperature to 80°C before discharging the material. Then, send the mixed material into a cooling agitator and cool it to ambient temperature (0°C ~ 40°C) while stirring.

[0071] c. drying the mixture; the drying time is 1.5 to 3 hours and the temperature is 60 to 100°C.

[0072] C. Mixing.

[0073] Put the surface treated short glass fiber and polypropylene mixture into the storage barrel respectively. To produce 50% short glass fiber reinforced polypropylene particles, the surface treated short glass fiber and polypropylene mixture can be mixed in a 50:50 ratio, and then conveyed to the mixer hopper by the feeder. After being mixed evenly by the mixer, it is conveyed to the extruder by the conveyor. The short glass fiber content can be adjusted according to the product characteristics.

[0074] The dust generated in the loading and mixing stages is collected in a closed compartment under negative pressure, introduced into a bag dust collector for treatment, and then discharged through an exhaust pipe.

[0075] (2) Extrusion

[0076] After the mixer stirs evenly, the mixed material is extruded and granulated in an extruder by a melt impregnation method to obtain glass fiber reinforced polypropylene particles. The extruder temperature is set between 100 and 200°C, and the impregnation die temperature is set to 200°C.

[0077] The extrusion process is a simple physical melting change process. After the material is transported to the extruder barrel, it is electrically heated. As the material moves forward in the barrel, it gradually becomes plastic and is squeezed and compacted. Under the action of the screw rotation and pressure, the material is pushed to the die head and passes through the mold in the die head to form the required plastic strip.

[0078] In the granulation process, the temperatures of the various zones of the screw extruder are as follows: the temperature of the first heating zone T1 = 100°C to 120°C, the temperature of the second heating zone T2 = 130°C to 140°C, the temperature of the third heating zone T3 = 150°C to 160°C, the temperature of the fourth heating zone T4 = 160°C to 170°C, the temperature of the fifth heating zone T5 = 170°C to 180°C, the temperature of the sixth heating zone T6 = 180°C to 190°C, the temperature of the seventh heating zone T7 = 190°C to 200°C, the temperature of the eighth heating zone T8 = 190°C to 200°C, the temperature of the ninth heating zone T9 = 190°C to 200°C, and the temperature of the extrusion die head = 180°C to 205°C. The screw speed is 140 to 200 rpm / min; the equipment used is a ZSK-25WLE twin-screw extruder purchased from WP Company of Germany;

[0079] The extruded waste gas is collected in a closed compartment under negative pressure, treated by an activated carbon adsorption device and then discharged through an exhaust pipe.

[0080] (3) Cooling

[0081] The plastic strips extruded by the extruder are cooled to about 70°C through a circulating cooling water tank. The water in the cooling tank is circulated for use.

[0082] (4) Blowing water

[0083] At the end of the cooling water tank, a hair dryer is used to dry the moisture on the surface of the plastic strip, and the water blown off enters the circulating cooling water tank for recycling.

[0084] (5) Pelletizing

[0085] The semi-finished plastic strips that have been cooled and formed are cut into 4mm granular finished products by a rotating blade. The short glass fibers in the granular finished products are evenly dispersed without anisotropy problems, which improves the structural strength of the product.

[0086] (6) Screening and drying

[0087] The finished glass fiber reinforced polypropylene particles after pelletizing enter the pelletizing machine, and the particles that meet the particle size requirements are screened out and transported to the storage bin, and the unqualified particles are collected and reused.

[0088] The glass fiber reinforced polypropylene particles are dried to obtain dried particles; the drying time is 24 to 48 hours and the temperature is 60 to 100°C.

[0089] Product warpage test evaluation:

[0090] A rectangular plate (length 300 mm, width 100 mm, height 3 mm) was injection molded using the formula of Example 1 and Comparative Example 1. Then, 24 hours after the injection molding was completed, the front and back sides of the rectangular injection molded plate were placed horizontally in turn, and the distance between the top corner that deviated the most from the horizontal plane and the horizontal plane was recorded. The average value of the warpage of at least 5 plates was recorded as the test result.

[0091] Components Example 1 Comparative Example 1 PP 40 40 Glass fiber(length) 30(<2mm) 30(<8mm) filler 12 12 Dispersants 11 11 Tensile Strength 98 102 Bending Strength 214 220 Flexural modulus 6850 7340 Impact strength 45.2 50.2 Warping degree (mm) 0.7 2.3

[0092] As mentioned above, the use of short glass fiber (<2mm) can significantly improve the warping deformation of the injection molded flat plate, and the product strength performance is close. The use of short glass fiber can ensure the flatness of the plate and use the added glass fiber to improve its structural strength.

[0093] (III) FRP filling masterbatch process flow

[0094] (1) Grinding

[0095] After fine crushing and secondary screening, the FRP particles (1cm) are transported to the grinder through a pipeline for grinding. The equipment used is an ultra-fine pulverizer for crushing and screening, and the material is ground into FRP (resin) powder with a particle size of 0.15mm. The dust generated in the grinding process is collected by negative pressure in a closed compartment, introduced into a bag dust collector for treatment, and then discharged through an exhaust pipe.

[0096] (2) Loading and mixing

[0097] FRP powder, polypropylene (PP), paraffin wax and stearic acid are transported by a feeder to a mixer in a ratio of 85:10:3:2 for mixing. After being evenly mixed by the mixer, they are transported to the extruder by a conveyor.

[0098] a. First, pour 85 kg of FRP powder into a high-speed mixer at a speed of 900 rpm and stir for later use.

[0099] b. Pour 10 kg of polypropylene, 3 kg of paraffin wax and 2 kg of stearic acid into a high-speed mixer at a speed of 900 rpm and mix until the friction heat generated by the mixing causes the material temperature to rise to 80°C before discharging the material. Then, the mixed material is sent to a cooling agitator and cooled to ambient temperature (0°C ~ 40°C) under stirring.

[0100] c. Drying the mixed powder; the drying time is 1.5 to 3 hours and the temperature is 60 to 100°C.

[0101] The dust generated during the feeding and mixing process is collected by negative pressure in a closed compartment, introduced into a bag dust collector for treatment, and then discharged through an exhaust pipe.

[0102] (3) Extrusion

[0103] The mixed material is extruded and granulated in an extruder by a melt impregnation method to obtain a glass fiber reinforced plastic filling masterbatch. The extruder temperature is set between 100 and 200 degrees Celsius, and the impregnation die temperature is set at 200 degrees.

[0104] The extrusion process is a simple physical melting change process. After the material is transported to the extruder barrel, it is electrically heated. As the material moves forward in the barrel, it gradually becomes plastic and is squeezed and compacted. Under the action of the screw rotation and pressure, the material is pushed to the die head and passes through the mold in the die head to form the required plastic strip.

[0105] In the granulation process, the temperatures of the various zones of the screw extruder are as follows: the temperature of the first heating zone T1 = 100°C to 120°C, the temperature of the second heating zone T2 = 130°C to 140°C, the temperature of the third heating zone T3 = 150°C to 160°C, the temperature of the first and fourth heating zones T4 = 160°C to 170°C, the temperature of the fifth heating zone T5 = 170°C to 180°C, the temperature of the sixth heating zone T6 = 180°C to 190°C, the temperature of the seventh heating zone T7 = 190°C to 200°C, the temperature of the eighth heating zone T8 = 190°C to 200°C, the temperature of the ninth heating zone T9 = 190°C to 200°C, and the temperature of the extrusion die head = 180°C to 205°C. The screw speed is 140 to 200 rpm / min; the equipment used is a ZSK-25WLE twin-screw extruder purchased from WP Company of Germany;

[0106] The extruded waste gas is collected in a closed compartment under negative pressure, treated by an activated carbon adsorption device, and then discharged through an exhaust pipe.

[0107] (4) Cooling and pelletizing

[0108] The FRP filling masterbatch is cooled by air, and an electric fan is used to cool the extruded material. The temperature of the material drops to about 70°C during the process. The semi-finished product that has been cooled and formed is cut into granular finished products with a particle size of 4mm by a rotating blade.

[0109] (5) Screening

[0110] The finished product after pelletizing enters the pelletizing machine, and the particles that meet the particle size requirements are screened out and transported to the storage bin, while the unqualified particles are collected and reused.

[0111] FRP filler masterbatch characteristics evaluation:

[0112] The formulations of Example 2 and Comparative Example 2 were used for injection molding to produce sheet specimens with a thickness of 5 mm. The surface of the sheet specimen was polished with a sander, and the sheet specimen was placed in a constant temperature water tank (the water temperature was set at 23 degrees), and after soaking for a certain period of time, the sheet specimen was taken out and the surface was wiped dry, and the mass change before and after immersion was measured, and the water absorption rate was calculated based on the mass change compared with the original mass as the test result.

[0113] Components Example 2 Comparative Example 2 PP 25 25 Glass fiber(length) 45(<2mm) 45(<2mm) Filler (ingredient) 12(Glass fiber reinforced plastic powder) 12(Calcium carbonate) Dispersants 11 11 Tensile Strength 115 105 Bending Strength 248 226 Flexural modulus 7420 6980 Impact strength 57.1 49.4 Water absorption (%) 3 6

[0114] The obvious improvement of using glass fiber reinforced plastic powder as mentioned above reduces the water absorption of the product and improves the strength of the product.

[0115] (IV) Packaging box molding process

[0116] like Figure 1 In the process shown, the glass fiber reinforced particles and FRP filling masterbatch particles prepared above are used for layered and zoned loading and then molded to prepare packaging boxes.

[0117] The packaging box molding preparation method and steps are as follows:

[0118] The shape of the package box is as follows: Figure 2 As shown, it includes multiple panel areas 1 and bending connection areas 2. The dotted line position between two panel areas 1 is the bending connection area 2, which connects the panel areas 1 on both sides and provides the necessary bending function. After bending, the multiple panel areas 1 are formed as shown in FIG. Figure 3 The three-dimensional packaging box shown.

[0119] When the packaging box is molded, a mold corresponding to the packaging box is used. The mold has an upper mold and a lower mold, such as Figure 4 The cross-sectional structure of the lower mold assembly is shown, wherein the lower mold assembly has a main mold cavity 3 in the shape of a package box plane unfolding, and the contour of the main mold cavity 3 is consistent with the shape of the package box plane unfolding, and is used to accommodate materials and form a complete package box unfolding plane.

[0120] For each panel area 1 of the packaging box, a corresponding sub-mold cavity 11 is formed. The depth of the sub-mold cavity 11 is greater than the main mold cavity 3, and the depth of the sub-mold cavity is 2-4 times the depth of the main mold cavity. The sub-mold cavity 11 is used to hold the material to form the main body of each panel of the packaging box. The upper mold assembly has a relatively flat molding work surface, which can be a flat surface or a regular pattern surface. Figure 4 As shown, three sub-mold cavities 11 located in the lower part of the lower mold assembly and one main mold cavity 3 located in the upper part are shown.

[0121] (1) Preparation

[0122] According to the above-mentioned granulation process, a certain amount of glass fiber reinforced particles and glass fiber reinforced plastic filler masterbatch particles are prepared respectively, and a certain amount of PP particles are prepared at the same time.

[0123] Glass fiber reinforced particles and FRP filler masterbatch particles can be formulated in the following form:

[0124] Polypropylene was K8003 produced by Sinopec. Antioxidants 1010 and 168 were produced by Nanjing Shuguang Chemical Plant. Dispersants, toughening agents, etc. were all commercially available chemicals.

[0125] Components and ratios of Examples 1-4 in the table (the following examples are all calculated by weight percentage)

[0126]

[0127] In Example 1 and Example 2, short glass fibers (<2 mm) are used as raw materials. During the preparation, all raw materials are fully mixed in proportion and then extruded and granulated by an extruder to obtain glass fiber reinforced particles.

[0128] In Example 3 and Example 4, glass fiber reinforced plastic powder is used as raw material. During the preparation, all raw materials are fully mixed in proportion and then extruded and granulated by an extruder to obtain glass fiber reinforced plastic filling masterbatch particles;

[0129] The different glass fiber reinforced particles and FRP filler masterbatch particles formed in Examples 1-4 can be selected in the charging according to their different performance differences.

[0130] (2) Preheating

[0131] Before various materials are loaded into the mold cavity, the upper mold, lower mold and frame of the mold are preheated respectively, and the preheating temperature is controlled at a temperature of 80 to 110°C.

[0132] (3) Layered loading

[0133] (3-1) Figure 5 As shown, the material is laid in the sub-mold cavity 11 of the lower mold. The glass fiber reinforced particles and the glass fiber reinforced plastic filling masterbatch particles are laid in batches by a powder spreading machine. The glass fiber reinforced particles can be laid first, that is, a bottom glass fiber reinforced particle layer 111 is first formed in the sub-mold cavity.

[0134] (3-2) Then, the FRP filling masterbatch particles are placed to continue to form an intermediate layer of FRP filling masterbatch particles 113 in the sub-mold cavity 11.

[0135] The glass fiber reinforced particle layer 111 is about 1 / 3 of the depth of the sub-mold cavity, and the glass fiber reinforced plastic filled masterbatch particle layer 113 is about 2 / 3 of the depth of the sub-mold cavity 11; after the two layers of fabric are completed, the sub-mold cavity 11 is fully filled.

[0136] The sub-mold cavity 11 has two layers of composite material particles.

[0137] (3-3) Continue to lay PP particles in the main mold cavity 3, and then use the PP particles to lay them in the entire main mold cavity, that is, fill the main mold cavity 3 with PP particles to form an intermediate PP particle layer 31. The PP particles need to be added with necessary toughening agent (10%), and the toughening agent is nitrile rubber. The intermediate PP particle layer 31 is about 1 / 2 of the depth of the main mold cavity 3.

[0138] (3-4) Continue to place glass fiber reinforced particles in the main mold cavity 3, that is, form a top layer of glass fiber reinforced particles 33 in the main mold cavity 3.

[0139] The main mold cavity 3 has two layers of composite material particles.

[0140] (4) Heating and pressurizing

[0141] The upper and lower molds are heated at a rate of 0.5-2°C / min, and pressurized when the temperature approaches the gel temperature of the raw material. The pressure is 3-7Mpa, and the hydraulic press is 250-500 tons. The forming temperature (i.e., the molding temperature) is generally about 120-150°C; keep warm for 1-5 minutes.

[0142] (5) Demolding, shaping, trimming, inspection, packaging and storage.

[0143] After the molding is completed, the packaging box board is unfolded in a plane, and a four-layer structural board is formed in the main part of each panel area (the sub-mold cavity 11 area), wherein the bottom layer 111 and the top layer 33 have reinforced glass fibers, which can provide the panel with anti-deformation effect and increase wear resistance; the middle layer 113 has glass fiber reinforced plastic filler, which increases the structural strength and can improve and reduce the water absorption of the board. The bending connection part between each panel area (the main mold cavity area located around the sub-mold cavity) forms a two-layer structural board, with a middle layer 31 composed of polypropylene PP added with a toughening copolymer, which improves the toughness of part of the board as the bending connection area 2.

[0144] Figure 2-Figure 3 The structure of the packaging box is shown in FIG. 1 , which includes a plurality of panel areas 1 and mutually bent connection areas 2. The inner and outer layers 111 and 33 of the panel area 1 have reinforced glass fibers to increase the wear resistance during use, and the reinforced glass fibers ensure that the panel surface is flat and does not produce warping and deformation. Therefore, when producing large-sized packaging boxes, there is no need to significantly increase the thickness of the panel, and the product uses less material and is lightweight. The fiberglass filler of the middle layer 113 increases the structural strength and improves the lateral and vertical pressure-bearing capacity of the panel without causing surface collapse or structural bending. The fiberglass filler also reduces the water absorption of the panel and has a better moisture-proof effect.

[0145] The bending connection area 2 uses an intermediate toughness layer 31 and an outer reinforced glass fiber layer 33. The double-layer composite structure has sufficient connection strength and can also ensure the bendability of the area.

[0146] The bending connection area 2 has a double-layer composite property, and can achieve easy bending without using an "S-shaped" molding structure in the connection area, thereby simplifying the molding process.

[0147] Figure 3 The outer surface of the three-dimensional packaging box with a central bending structure is the reinforced glass fiber layer 33.

[0148] (V) Packaging box extrusion, blow molding, injection molding process

[0149] In other embodiments, Figure 6 As shown, there is no need to pre-prepare glass fiber reinforced particles and FRP filler masterbatch particles. FRP powder and short glass fibers can be mixed into a base material and then extruded, blow molded, or injection molded to prepare and produce packaging boxes. The following production process can be used.

[0150] (1) Grinding to prepare glass fiber reinforced plastic powder

[0151] After fine crushing and secondary screening, the FRP particles (1cm) are transported to the grinder through a pipeline for grinding. The equipment used is an ultra-fine pulverizer for crushing and screening, and the material is ground into 0.15mm FRP (resin) powder. The dust generated in the grinding process is collected by negative pressure in a closed compartment, introduced into a bag dust collector for treatment, and then discharged through a 15m high exhaust pipe.

[0152] (2) Surface treatment of short glass fibers.

[0153] Pour the short glass fibers obtained after screening into a high-speed mixer and stir at high speed. When the material temperature rises to 100°C, add a coupling agent for surface treatment. After the treated short glass fibers are cooled, they are packaged for later use.

[0154] The silane coupling agent and industrial alcohol are mixed at a volume ratio of 1-5:5-10 at room temperature for 20-30 minutes to obtain a silane coupling agent after alcoholysis; the silane coupling agent is γ-aminopropyltriethoxysilane;

[0155] The alcoholyzed silane coupling agent is mixed with the short glass fiber and then stirred to obtain the surface-treated short glass fiber; the weight ratio of the alcoholyzed silane coupling agent to the short glass fiber is 1-5:95-99, the stirring time is 10-30 minutes, the speed is 1300-2000 rpm / min, and the equipment used is a high-speed stirrer;

[0156] (3) Mixing of base material components

[0157] FRP powder, polypropylene (PP), paraffin (dispersant), and stearic acid (lubricant) are transported by a feeder to a mixer for mixing in a ratio of 10:15:3:2. After being evenly mixed by the mixer, they are transported to the extruder by a conveyor.

[0158] a. First, pour 10 kg of FRP powder into a high-speed mixer at a speed of 900 rpm and stir for later use.

[0159] b. Pour 15kg of polypropylene, 3kg of paraffin wax and 2kg of stearic acid into a high-speed mixer at a speed of 900 rpm and mix until the friction heat generated by the mixing causes the material temperature to rise to 80°C before discharging the material. Then, the mixed material is sent to a cooling agitator and cooled to ambient temperature (0°C ~ 40°C) under stirring.

[0160] c. Drying the mixed powder; the drying time is 1.5 to 3 hours and the temperature is 60 to 100°C.

[0161] The dust generated during the feeding and mixing process is collected in a closed compartment under negative pressure, introduced into a bag dust collector for treatment, and then discharged through a 15m high exhaust chimney.

[0162] (4) Mixing

[0163] Put the surface treated short glass fiber and polypropylene mixture into the storage barrel respectively. The surface treated short glass fiber and polypropylene mixture can be mixed in a ratio of 30:70, transported by the feeder to the mixer hopper, stirred evenly by the mixer, and transported by the conveyor to the extruder, blow molding machine or injection molding machine.

[0164] (5) Extrusion, blow molding or injection molding to prepare packaging boxes.

[0165] The melt index of the mixed material is 2-6kg / 10min, the density is 0.948-0.957g / cm3, and the extrusion, blow molding or injection molding temperature range is 190-210°C. After extrusion, blow molding or injection molding, the packaging box board is obtained after demoulding.

[0166] Weigh the materials according to the components and proportions provided in Table 1;

[0167] The material performance test of the product is carried out according to GB standards, and the test results are shown in Table 2.

[0168] The following materials are used in the examples:

[0169] The polypropylene was K8003 produced by Sinopec. Antioxidant 1010, antioxidant 168 and light stabilizer 3346 were produced by Nanjing Shuguang Chemical General Plant. Dispersants and lubricants were all commercially available chemicals. The dispersant was paraffin. The lubricant was stearic acid.

[0170] Table 1 Components and ratios of Examples 1-4 (the following examples are all calculated by weight percentage)

[0171] Components Example 1 Example 2 Example 3 Comparative Example 4 PP 35 30 30 30 Glass fiber(length) 20(<2mm) 25(<2mm) 20(<2mm) 25(<2mm) Filler (ingredient) 22(Glass fiber reinforced plastic powder) 22(Glass fiber reinforced plastic powder) 27(Glass fiber reinforced plastic powder) 22(Calcium carbonate) Dispersants 11 11 11 11 Lubricants 10.5 10.5 10.5 10.5 Coupling agent 0.5 0.5 0.5 0.5 Antioxidant 1010 0.2 0.2 0.2 0.2 Antioxidant 168 0.3 0.3 0.3 0.3 Light Stabilizer 0.5 0.5 0.5 0.5

[0172] In the embodiment, short glass fibers are used as raw materials, and all raw materials are fully mixed in proportion to prepare the packaging box through extrusion, blow molding or injection molding;

[0173] Table 2 Performance of Examples 1-4 (GB)

[0174]

[0175]

[0176] It can be seen from the table that increasing the glass fiber content can increase the tensile, bending and impact strength of the product. In addition, using glass fiber reinforced plastic powder as filler has improved the strength characteristics of the product compared with conventional calcium carbonate filler.

[0177] Warpage assessment method for processed flat products:

[0178] Similar to the characteristic test of glass fiber reinforced particles, the use of short glass fibers significantly improved the warpage of injection molded flat plates.

[0179] Method for evaluating water absorption of processed products:

[0180] Similar to the characteristic test of FRP filled masterbatch, the use of FRP powder can also significantly improve and reduce the water absorption of the product.

[0181] In the above embodiments, the thermoplastic plastic substrate may be one or more of high-density polyethylene, low-density polyethylene, linear low-density polyethylene, and polypropylene.

[0182] The coupling agent can be one or more of isocyanate, aluminate, titanate and silane coupling agents.

[0183] Finally, it should be noted that the above description is only an explanation of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail, those skilled in the art can still modify the technical solutions described above or replace some of the technical features with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for producing packaging boxes for used wind turbine blades, characterized in that: The following steps are involved: Step 1: Recycle the wind turbine blades and sort out short glass fibers and glass fiber reinforced plastic particles; Step 2: short glass fibers and thermoplastic substrates are subjected to a hot extrusion process to prepare glass fiber reinforced particles; Step 3, preparing a FRP filler masterbatch by hot extrusion of FRP particles and thermoplastic substrate; Step 4: Use glass fiber reinforced particles, FRP filler masterbatch and thermoplastic substrate through a molding process to produce packaging boxes.

2. The method for producing packaging boxes for used wind turbine blades according to claim 1, characterized in that: The flat unfolded packaging box produced by molding has several panel areas and bending connection areas; the panel area has a multi-layer composite material, the inner and outer surface layers are made of glass fiber reinforced particles, and the first middle layer is made of glass fiber reinforced plastic filled masterbatch.

3. The method for producing packaging boxes for used wind turbine blades according to claim 2, characterized in that: The bending connection area has a multi-layer composite material, the outer surface layer is made of glass fiber reinforced particles and the inner surface layer is made of a thermoplastic matrix.

4. The method for producing packaging boxes for used wind turbine blades according to claim 3, characterized in that: The inner surface layer of the bending connection area is composed of a thermoplastic base material and a toughened copolymer.

5. The method for producing packaging boxes for used wind turbine blades according to claim 3, characterized in that: The outer surface layer of the panel area and the outer surface layer of the bending connection area form a structure of the same layer; there is also a second intermediate layer between the outer surface layer of the panel area and the first intermediate layer, and the second intermediate layer is made of a thermoplastic substrate.

6. The method for producing packaging boxes for used wind turbine blades according to claim 5, characterized in that: The second middle layer of the panel area and the inner surface layer of the bending connection area form a structure with the same layer.

7. The method for producing packaging boxes for used wind turbine blades according to claim 6, characterized in that: During molding, a mold corresponding to the unfolded plane of the packaging box is used. The mold comprises an upper mold and a lower mold, wherein the lower mold assembly has a main mold cavity of the unfolded shape of the packaging box plane. The contour of the main mold cavity matches the unfolded shape of the packaging box plane, and is used to accommodate materials and form a complete unfolded plane of the packaging box; for each component panel area of ​​the packaging box, a corresponding sub-mold cavity is formed, the depth of the sub-mold cavity is greater than that of the main mold cavity, and the depth of the sub-mold cavity is 2-4 times that of the main mold cavity. The sub-mold cavity is used to accommodate materials to form the main body of each panel of the packaging box.

8. The method for producing packaging boxes for used wind turbine blades according to claim 7, characterized in that: Fabrication before molding; The material is laid in the sub-mold cavity of the lower mold; the glass fiber reinforced particles and the glass fiber reinforced plastic filling masterbatch particles are laid in batches by a powder spreading machine; the glass fiber reinforced particles can be laid in first, that is, the inner surface glass fiber reinforced particle layer is first formed in the sub-mold cavity; Then, the FRP filling masterbatch particles are spread in to continue forming the first middle layer of FRP filling masterbatch particles in the sub-mold cavity; after the two layers of spreading are completed, the sub-mold cavity is fully filled.

9. The method for producing packaging boxes for used wind turbine blades according to claim 8, characterized in that: First, PP particles are laid in the main mold cavity, and then the PP particles are laid in the entire main mold cavity, that is, the main mold cavity is filled with PP particles to form a second intermediate layer of PP particles. Continue to place the glass fiber reinforced particles in the main mold cavity, that is, form an outer surface glass fiber reinforced particle layer in the main mold cavity.

10. A method for producing packaging boxes for used wind turbine blades, characterized in that: The following steps are involved: Step 1: Recycle the wind turbine blades and sort out short glass fibers and glass fiber reinforced plastic particles; Step 2, modifying the surface of the short glass fiber; Step 3, the FRP particles are further crushed to produce FRP powder; Step 4: Use short glass fibers, glass fiber reinforced plastic powder and thermoplastic substrates to produce packaging boxes through extrusion, blow molding and injection molding processes.

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