Production line and production method of unidirectional fiber reinforced prepreg

Abstract

The invention provides a production line of unidirectional fiber reinforced prepreg, which comprises a spinning unit, a fiber processing unit, a sizing unit and a plurality of transmission rollers arranged among the units and used for transmitting fibers, which are arranged in sequence, the fiber processing unit comprises an arrangement roller and does not comprise a fiber winding device; spinning holes in the spinning nozzles are staggered in the axis direction of the arrangement roller, and the fiber processing unit is directly connected with the sizing unit. The invention further discloses a production method of the unidirectional fiber reinforced prepreg based on the production line. According to the scheme, the processes of fiber bundling, winding, unwinding, arranging, filament spreading and the like in the conventional production process are omitted, and the production process is greatly shortened. Besides, the obtained fiber thin layer is better in uniformity, the prepared prepreg is thinner, the utilization rate of the fiber performance is higher, and the mechanical property of the prepreg is further improved.

Description

Technical Field

[0001] The invention relates to the field of composite material production, and in particular to a production line and a production method of unidirectional fiber reinforced prepreg. Background Art

[0002] Prepreg refers to a composite material product that is made by premixing a resin matrix with a reinforcing material and processing it through a specific process. It has a specific width and thickness and can be further processed and formed. Usually, prepreg is in the form of a sheet or a strip. Its production is generally to impregnate short fibers, continuous fibers or fabrics with a resin matrix to make a composite material with resin as the matrix and continuous fibers or fabrics as reinforcements. Among the short fibers, continuous fibers or fabrics used as reinforcements, the continuous fibers have good fiber orientation due to their unidirectional arrangement. Therefore, the obtained prepreg can make fuller use of the mechanical properties of the fibers.

[0003] In the prior art, the production process of prepregs with continuous fibers as reinforcement is long and complicated. For example, in patent documents CN110087847A and CN212223269U, a yarn roll is unwound on a creel, multiple yarns are arranged through a wire guide, and the yarns are spread and laid flat, and then resin is applied to the unidirectionally laid fibers to prepare prepreg. The above-mentioned steps of spreading the yarns into fibers are cumbersome and complicated, and in actual production, the bundled yarns are difficult to be spread again into uniform and parallel fiber monofilaments. The entangled fibers will reduce the utilization rate of the fiber performance, and cause the thickness of the prepreg to become thicker and the uniformity to deteriorate, thereby adversely affecting the mechanical properties of the prepreg. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a production line of unidirectional fiber reinforced prepreg and a production method of unidirectional fiber reinforced prepreg, and the specific scheme is as follows:

[0005] A production line for unidirectional fiber reinforced prepreg, characterized in that it includes a spinning unit, a fiber processing unit, a gluing unit arranged in sequence, and a plurality of transmission rollers for transmitting fibers arranged between the units, wherein the spinning unit includes a spinneret, on which a plurality of spinneret holes are arranged, the fiber processing unit includes an arranging roller, and does not include a fiber winding device; the spinneret holes on the spinneret are staggered with each other in the axial direction of the arranging roller, and the fiber processing unit is directly connected to the gluing unit.

[0006] The arrangement roller is actually a transmission roller, and its function is to arrange the fibers ejected from the spinneret on the roller surface so that the fibers form a unidirectional fiber plane on the roller surface, and the fibers in the plane are arranged in parallel. The direct connection refers to the front and rear positional relationship of the equipment on the production line. There are no other processing units between the two except the transmission mechanism, and it is not limited to specific physical contact between the two devices. Specifically for the present invention, direct connection means that there is no additional equipment between the fiber processing unit and the glue application unit. After the fibers are processed by the fiber processing unit, they are directly transported to the glue application unit.

[0007] The staggered arrangement direction refers to that the spinnerets are staggered in the arrangement direction so that the fiber filaments ejected from the spinnerets do not overlap with each other, thereby allowing the fiber filaments ejected from the spinneret to be laid flat on a guide roller without being staggered.

[0008] Furthermore, the arrangement width of the spinnerets is smaller than the length of the arrangement roller and the transmission roller. The arrangement width of the spinnerets refers to the maximum width of the arrangement pattern of the spinnerets formed on the spinneret in the axial direction of the arrangement roller.

[0009] Furthermore, the spinning unit is a cellulose fiber spinning unit, the spinneret of the cellulose fiber spinning unit is a spinneret, the cellulose fiber spinning unit also includes a coagulation bath, and the arrangement rollers of the fiber processing unit are arranged in the coagulation bath.

[0010] Furthermore, the fiber processing unit includes a fiber washing device.

[0011] Optionally, the fiber processing unit includes a fiber drying device. The drying device is not limited to heating drying, and devices that can be used for drying fibers, such as vacuum drying or airflow drying, can also be used as the drying device described in the present invention.

[0012] Optionally, the fiber processing unit includes at least one pair of fiber squeezing rollers and does not include a fiber drying device.

[0013] Furthermore, the glue applying unit includes a glue groove and a glue extrusion device, and the glue extrusion device is provided with a slit.

[0014] Furthermore, the glue application unit further includes a glue liquid drying device. The glue liquid drying device is not limited to heating drying, and devices such as vacuum drying or airflow drying that can be used to dry glue liquid can also be used as the drying device described in the present invention.

[0015] Furthermore, the glue application unit also includes a pressure roller device after drying.

[0016] A method for producing a unidirectional fiber reinforced prepreg, characterized in that it comprises the following steps:

[0017] (1) Spinning: The spinning device spins multiple fiber filaments through the spinneret holes;

[0018] (2) Fiber processing: the plurality of fiber monofilaments fall onto the arrangement roller to form a unidirectional fiber thin layer;

[0019] (3) Gluing: The fiber thin layer is transported to a gluing unit via a conveying roller for gluing to form a continuous strip prepreg of fiber-reinforced resin;

[0020] Furthermore, the method for producing the unidirectional fiber reinforced prepreg also includes the step of winding the continuous strip prepreg by a winding device.

[0021] Furthermore, in the spinning step of step (1), the fiber monofilaments are cellulose fibers.

[0022] Furthermore, the fiber processing step in step (2) also includes a water washing step of the fiber thin layer.

[0023] Optionally, in the fiber processing step of step (2), after the water washing step, a drying step of the fiber thin layer is included.

[0024] Optionally, in the fiber processing step of step (2), after the water washing step, a fiber thin layer pressing step is included to squeeze out the moisture in the fiber thin layer, and a drying step is not included.

[0025] Optionally, in the sizing step of step (3), a thermoplastic resin suspension (gas phase or liquid phase) or an aqueous thermosetting resin is applied to the fiber layer through a slit, and then the resin is dried.

[0026] A composite material, characterized in that it is prepared by stacking and compounding prepregs obtained by the above production line or method.

[0027] Beneficial effects:

[0028] In the production line of unidirectional fiber reinforced prepreg provided by the present invention, the fiber monofilaments spun by the spinning unit are laid flat into a non-entangled fiber thin layer by the fiber processing unit, and then the fiber processing unit is directly connected to the gluing unit, so that the fiber thin layer can be directly glued to prepare the unidirectional fiber reinforced prepreg. Compared with the conventional prepreg production process, the equipment for fiber bundling, winding, unwinding, arranging, and spreading is omitted, which greatly saves the equipment investment of the prepreg.

[0029] Correspondingly, in the production method of unidirectional fiber reinforced prepreg provided by the present invention, the spun fibers are directly laid into a unidirectionally arranged fiber thin layer, and then sizing is applied to obtain the unidirectional fiber reinforced prepreg, which eliminates the fiber bundling, winding, unwinding, arranging, and spreading processes in the conventional production process, greatly shortens the production process, and improves production efficiency. In addition, the method of directly arranging the fiber thin layer in the scheme of the present invention, compared with the method of first bundling and then spreading the fiber in the conventional steps, has better uniformity of the obtained fiber thin layer, no entanglement between the fibers, and better fiber orientation, so that the obtained prepreg is thinner and the utilization rate of the fiber performance is higher, thereby improving the mechanical properties of the prepreg. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the overall structure of the production line of unidirectional fiber reinforced prepreg provided by the present invention.

[0031] Figure 2 This is a schematic diagram of the fiber arrangement after spinning of the present invention.

[0032] The following are the descriptions of the reference numerals:

[0033] 11. Spinneret 12. Coagulation bath 21. Arrangement roller 22. Washing machine 23. First squeeze roller group 31. Glue extruder 32. Second squeeze roller group 33. Dryer 34. Pair of rollers 40. Winding device 51. Original liquid thin flow plane 52. Fiber thin layer 53. Prepreg DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be further clearly and completely described in the following text in combination with the drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. For the sake of clarity and conciseness, not all features of the actual implementation are described in the specification. However, it should be understood that many implementation-specific decisions must be made in the process of developing any such actual embodiment in order to achieve the specific goals of the developers. In order to avoid obscuring the invention due to unnecessary details, only the device structures closely related to the solutions according to the present invention are described in the drawings and descriptions. In order to more clearly show the structure of the device described in the present invention, some structures are omitted in the drawings to highlight the characteristic structures of the important parts.

[0035] Conventional unidirectional fiber reinforced prepreg production usually involves unwinding the fiber bundles from the package, arranging the fiber bundles in parallel through a creel, and then spreading the fiber bundles into parallel monofilaments before applying glue to the fibers to form a sheet of prepreg. This process is lengthy and cumbersome, and the fiber spreading is difficult. It is inevitable that the fibers will be entangled, and it is difficult to evenly spread the fibers in the fiber bundle into a single fiber layer, making it difficult to fully exert the mechanical properties of the fibers.

[0036] Based on the above situation, the present invention proposes a new prepreg production line and production method, which mainly includes three steps of fiber spinning, fiber processing and sizing, and aims to efficiently produce unidirectionally arranged fiber reinforced prepreg.

[0037] Spinning

[0038] In order to shorten the production process of unidirectional fiber reinforced prepreg, different from the prior art, the solution of the present invention directly lays the fibers into a unidirectionally arranged fiber layer after spinning is completed, and then applies glue to the fiber layer to obtain the prepreg. Therefore, in the spinning stage, the spinnerets on the spinneret used for spinning in the solution of the present invention should be staggered with each other so that the spun monofilaments can be arranged as a thin layer on the roller surface during the transmission process. The specific arrangement of the spinnerets is not limited in the present invention. As long as it is convenient for the monofilaments to be arranged as a fiber thin layer on the arrangement roller in the next step, it is feasible to arrange the spinnerets in a linear shape, an arc with a certain curvature, a curve or other shapes.

[0039] In prepreg products, the fiber arrangement density should be increased as much as possible, that is, the distance between the fiber filaments should be as small as possible, and the processing of the spinneret is more difficult if the spinning holes are closely arranged. Therefore, it is preferred that the spinneret holes can be arranged in multiple rows, and the spinnerets in each row are staggered in the arrangement direction, so that the rows of fibers spun are staggered, and when guided to the arrangement roller, the fibers in different rows will not overlap or entangle, thereby forming a fiber thin layer with a higher fiber arrangement density.

[0040] The fibers in conventional prepregs are usually selected from high-performance fibers, specifically carbon fibers, glass fibers, regenerated cellulose fibers, ultra-high molecular weight polyethylene, aramid, basalt fibers, etc. In the present invention, regenerated cellulose fibers or aramid fibers are preferred, and regenerated cellulose fibers are most preferred. Carbon fibers and glass fibers are common materials used as reinforcing phases of prepregs, but the production process of carbon fibers is complicated, involving many process parameters, and requires several windings during the production process, so it is difficult to directly and continuously produce thin fiber layers; while the spinning speed of glass fibers is fast, often exceeding 1000m / min, and the sizing process is difficult to reach this speed, so it is also difficult for glass fibers to adopt the solution of the present invention. Regenerated cellulose fibers such as viscose fibers and lyocell fibers have good single-filament strength, short production processes, and the spinning speed is easy to match the sizing process speed. Therefore, the inventors thought of combining high-performance fibers with slower spinning speeds such as regenerated cellulose fiber spinning with the sizing process for the production of unidirectional fiber reinforced prepregs.

[0041] Specifically, viscose fiber is made by alkalizing, squeezing, and yellowing cellulose, dissolving it in an alkaline solution to form a viscose spinning solution, which is then ejected through a spinneret into a coagulation bath to form viscose fiber. Depending on the viscose spinning process, equipment, and type of spun fiber, the spinning speed of viscose fiber can be 20-180 m / min. Lyocell fiber is made by dissolving cellulose pulp in an NMMO aqueous solution to form a spinning solution with a uniform texture, which is then ejected through a spinning plate to form a thin stream of the solution, which is cooled in an air gap and then enters a coagulation bath to form lyocell fiber. The spinning speed of lyocell is usually 10-200 m / min.

[0042] Of course, other fibers such as aramid fibers or ultra-high molecular weight polyethylene fibers may also be used in the present application, as long as they can be spun to form linearly arranged fibers and can match the speed of the subsequent sizing process.

[0043] Fiber processing

[0044] The fiber treatment step is a step of post-treating the spun fibers to ensure stable fiber performance. Depending on the different spinning processes of different fibers in the spinning step, different post-treatment processes are required for the fibers. For the scheme of the present invention, the necessary post-treatment process is to drop the multiple fiber filaments obtained in the spinning step onto the arrangement roller to form a fiber thin layer. This process is referred to as fiber arrangement in the present invention. In the present invention, it is preferred that the fibers are arranged when they contact the first roller after being ejected from the spinneret to avoid entanglement or overlap between the fiber filaments as much as possible, that is, after the fibers are ejected from the spinneret, the first roller in the transmission or turning process is the arrangement roller. When the spinning method is melt spinning or dry spinning, the arrangement roller is the first turning guide roller; when the spinning method is wet spinning or dry-jet wet spinning, the arrangement roller can be the first guide roller arranged in the coagulation bath. The arrangement roller requires a flat surface, and the length of the arrangement roller should be greater than the fiber arrangement width, so that when the fibers are laid on the roller surface, the fibers are prevented from being lateral offset and causing fiber entanglement.

[0045] The present invention preferably adopts regenerated cellulose fiber as reinforcing fiber, and accordingly, the processing of regenerated cellulose fiber also includes washing and drying process performed after fiber arrangement. The washing process is used to wash away the solvent remaining in the fiber, and the drying process is used to remove the moisture in the fiber, so as to apply resin on the fiber thin layer in the next step. Since the fibers in the fiber thin layer are all unbundled monofilaments, the fiber thin layer thickness is theoretically only the diameter of a monofilament (about 1-30 microns, preferably 5-20 microns, more preferably 8-15 microns), which is easier to wash and dry than the fiber bundle after bundling, so the washing and drying process of the fiber thin layer can be set shorter. In addition, to ensure that the fiber monofilaments in the fiber thin layer do not deviate, the washing and drying conditions need to be more gentle, and the lateral position of the monofilament is avoided to be affected by water flow or air flow, and the washing step is preferably performed between two pairs of pressing rollers, and the fiber thin layer is washed by soaking in clean water or spraying with water mist. The drying process is preferably carried out in a non-contact manner to dry the fiber.

[0046] Sizing

[0047] The sizing step is to apply resin on the fiber layer to obtain a resin prepreg reinforced by unidirectional fibers. The resin used can be a thermoplastic or thermosetting resin, such as epoxy resin, unsaturated resin, polyethylene, polypropylene, polylactic acid, etc. The resin can be applied by melt extrusion, casting, powder spreading, impregnation, etc.

[0048] As a preferred embodiment, the present invention adopts a thermoplastic resin suspension (gas phase or liquid phase) or a thermosetting resin solution to be applied to a thin layer of fibers by slit extrusion, and after the application is completed, the resin is melted and cooled or heat-cured to obtain a unidirectional fiber-reinforced prepreg. When the applied resin is an aqueous resin, the drying process in the fiber processing step can be omitted, and after the thin layer of fibers is squeezed out of most of the water by a pair of press rollers, an aqueous resin is directly applied to it without drying, and then it is sent to a drying device for drying together, so that the arrangement can reduce the layout of the equipment and save process steps. Alternatively, a thermoplastic resin powder can be applied to a thin layer of fibers that has dried water, and a unidirectional fiber-reinforced prepreg is obtained after heating and pressurization, and compared to a resin suspension that applies a liquid phase, the method of applying a thermoplastic resin powder is not limited by the resin drying rate, and the production rate of the prepreg can be increased.

[0049] The gluing step is usually the slowest step in the prepreg production process, so the speed of the gluing step determines the production speed of the prepreg. The speed of the gluing step in the present invention is 0-150 m / min, preferably 30-120 m / min, and more preferably 60-100 m / min. Generally speaking, the speed of applying thermoplastic resin powder can be set faster, up to 100 m / min or more, and the speed of using resin suspension as glue is usually slower.

[0050] The present invention is described in more detail below by way of examples.

[0051] Example 1

[0052] This embodiment provides a production line for unidirectional fiber reinforced prepreg, such as Figure 1 As shown, it includes a spinning unit consisting of a spinneret 11 and a coagulation bath 12; a fiber processing unit consisting of an arrangement roller 21, a washing machine 22 and a first squeezing roller group 23; a sizing unit consisting of a glue extruder 31, a second squeezing roller group 32, a dryer 33 and a pair of rollers 34; a prepreg winding device 40, and a plurality of transmission rollers.

[0053] The rows of holes on the spinneret 11 are staggered in the transverse direction (i.e., the axial direction of the arrangement roller 21). The arrangement roller 21 is arranged below the spinneret 11 and in the coagulation bath 12. A plurality of guide rollers are arranged after the arrangement roller 21, followed by a water washer 22, wherein the water washer 22 is provided with a plurality of water washing roller groups, each of which is provided with a corresponding spraying device, and the spraying device sprays water flow or water mist onto the fiber thin layer to wash away the residual solvent in the fiber. A first squeezing roller group 23 is arranged after the water washer 22, which is used to squeeze out most of the water in the fiber thin layer after washing. A glue extruder 31 is arranged after the first squeezing roller group 23, which is used to extrude and apply glue to the fiber thin layer. In this embodiment, a slit is arranged at the bottom of the glue extruder 31, and the thermosetting resin suspension in the glue tank of the glue extruder 31 is extruded onto the fiber thin layer through the slit. A second extrusion roller group 32 is provided behind the glue extruder, which is used to squeeze out excess glue on the fiber thin layer and control the thickness of the glue layer after the fiber thin layer is glued. The gap between the two roller surfaces of the second extrusion roller group 32 is adjustable, and can be used to prepare prepregs of different thickness specifications. A dryer 33 is provided behind the second extrusion roller group 32, which is used to dry the moisture in the resin glue to obtain unidirectional fiber reinforced prepreg. A pair of rollers 34 are provided behind the dryer 33, which serve as traction rollers for the prepreg and accurately control the thickness of the prepreg. A winding device 40 is provided behind the pair of rollers 34, which is used to store prepreg products. Depending on the type of prepreg product, the storage equipment of the hard prepreg production line can also be a cutting and stacking equipment, which is not specifically limited in the present invention.

[0054] Example 2

[0055] This embodiment provides a method for producing fiber prepreg. The specific steps are as follows:

[0056] 1. Spinning steps

[0057] 1.1 Preparation of spinning solution: cellulose pulp with an α-cellulose content greater than 90% is crushed, mixed with an NMMO aqueous solution, and dissolved at 87° C. to obtain a homogeneous cellulose spinning solution;

[0058] 1.2 Spinning: The spinning solution is transported to the spinneret 11 through the heat-insulating pipeline, and the spinning solution is ejected from the spinneret 11 through the spinneret holes to form multiple rows of solution thin flow planes 51. The single solution thin flows in different rows of solution thin flow planes 51 are staggered in the arrangement direction. The solution thin flows leaving the spinneret 11 pass through a cold air gap of 15 cm in length, and then enter the coagulation bath of the coagulation bath tank 12 to form primary fibers. The coagulation bath is a 20% NMMO aqueous solution.

[0059] 2. Fiber processing steps

[0060] 2.1 Fiber Arrangement: The primary fibers are laid flat on the arrangement roller 21 in parallel with each other, forming a fiber thin layer 52 on the arrangement roller 21. Since the fibers ejected from the spinneret 11 are arranged linearly and in parallel, and the fibers in different rows are staggered, when the fibers are laid flat on the arrangement roller 21, there is no overlap or entanglement between the fibers, and a parallel fiber thin layer 52 can be formed on the arrangement roller 21, such as Figure 2 As shown. In the subsequent conveying, they are all transported in the form of fiber thin layers through the conveying roller. The conveying speed of the conveying roller is 40m / min.

[0061] 2.2 Water washing: The laid fiber thin layer 52 is transported to the water washing machine 22 via a transmission roller. The water washing machine 22 is composed of a plurality of groups of water washing rollers and corresponding spraying devices. The spraying device sprays clean water onto the fiber thin layer to wash away the residual NMMO in the fiber thin layer 52.

[0062] 2.3 Pressing: The washed fiber sheet 52 is pressed by the first squeezing roller group 23, so that the moisture content in the fiber sheet is reduced to below 50%. At this time, the primary fiber has been converted into regenerated cellulose fiber, the diameter of the regenerated cellulose fiber is about 15 μm, the diameter dispersion coefficient is less than 5%, and the strength is greater than 5 cN / dte×.

[0063] 3. Gluing steps

[0064] 3.1 Gluing: The pressed fiber thin layer 52 is conveyed to the glue extruder 31. The glue in the glue tank of the glue extruder 31 is a thermosetting resin suspension. The glue extruder 31 is provided with an extrusion slit. When the fiber thin layer 52 is conveyed to the glue extruder 31, the glue is squeezed out from the slit and falls on the fiber thin layer 52. The fiber thin layer 52 with glue continues to be conveyed forward. After being squeezed by the second squeezing roller group 32, the fiber plane 52 is more tightly combined with the glue. At the same time, the excess glue is squeezed out to play the role of determining the thickness of the prepreg. Specifically, in this embodiment, the aqueous thermosetting resin dispersion is epoxy resin, and the solid content of the dispersion is 30%-60%, preferably 40%-50%, and 40% in this embodiment. The gap between the second extrusion roller sets 32 is 0.03-0.07 mm, preferably 0.03-0.06 mm, and more preferably 0.04-0.05 mm. In this embodiment, the gap between the second extrusion roller sets 32 is 0.05 mm.

[0065] 3.2 Drying: The fiber plane 52 squeezed by the second squeezing roller group 32 is transported to the dryer 33 with the glue to remove moisture from the fiber and the glue at high temperature, and at the same time promote the pre-curing of the thermosetting resin. The drying temperature is 60-100°C, and the residence time of the material in the dryer 33 is 1-10 minutes, preferably 1-5 minutes. In this embodiment, the residence time of the material in the dryer 33 is 3 minutes. The dried material is pre-stretched and thickness-set by the roller pair 34 to obtain the fiber-reinforced prepreg 53. In this embodiment, the gap between the roller pair 34 is 0.02mm.

[0066] The obtained prepreg 53 is rolled up by the winding device 40. It can also be cut into sheets by a cutting machine and then stacked for storage, which is a conventional practice in the art and will not be described in detail here.

[0067] In the method provided in this embodiment, the spun fibers are directly formed into a fiber plane 52 through the cooperation of the spinneret holes on the spinning plate 11 and the arrangement roller 21, and the fiber plane 52 is directly subjected to corresponding fiber post-treatment, thereby eliminating the steps of fiber bundling, winding, unwinding, and fiber spreading, and greatly improving the production efficiency of the prepreg. In addition, by using water-based resin as the glue, only a pair of extrusion rollers are used to squeeze out most of the water in the fiber plane 52, and the undried fiber plane 52 can be dried together with the water-based thermosetting resin glue in the dryer 33 after the glue is applied, further saving equipment investment and shortening the process flow. The obtained prepreg has a thickness of 0.02 mm and a fiber content of 40%.

[0068] Example 3

[0069] Using the prepreg as raw material, two adjacent layers of prepreg were cross-stacked at an angle of 90° for 50 layers, and a composite material with a thickness of 1 mm was obtained after hot pressing at 120°C for 30 minutes. After testing, the mechanical properties of the composite material are shown in the following table.

[0070] project Test Standards Performance Indicators Fiber volume content / % / 40 <![CDATA[Density / (g / cm 3 )]]> ISO1183-1 1.26 Tensile strength / MPa ASTM D3039 320 Elongation at break / % ASTM D3039 2.1 Tensile modulus / GPa ASTM D3039 26

[0071] Comparative Example 1

[0072] In this comparative example, the cellulose fibers were spun from the same spinning solution as in Example 2, and then the fibers were bundled and rolled to obtain a cellulose fiber package, and then the cellulose fiber bundle package was unwound on a conventional creel, and then the fibers were spread by a spreading roller to obtain a cellulose fiber thin layer, and then the same aqueous thermosetting resin glue was applied to the fiber thin layer in the same manner as in Example 2, and a prepreg was obtained after drying. The prepreg obtained in this comparative example was overlapped with a 90° angle, and the number of layers was 20, and a composite material with a thickness of 1 mm was obtained by hot pressing. After testing, the mechanical properties of the composite material are shown in the following table.

[0073] project Test Standards Performance Indicators Fiber volume content / % / 40 <![CDATA[Density / (g / cm 3 )]]> ISO1183-1 1.26 Tensile strength / MPa ASTM D3039 144 Elongation at break / % ASTM D3039 1.8 Tensile modulus / GPa ASTM D3039 17

[0074] By comparing the performance of Example 3 with that of Comparative Example 1, it is found that the composite material prepared in Example 3 is compared with the composite material prepared in Comparative Example 1. When using the same content of reinforcing fiber, the specific tensile strength and specific tensile modulus of the prepreg prepared by this process are far superior to those of the composite material prepared by the conventional process, thereby improving the utilization rate of the fiber performance. Therefore, under the premise of obtaining the same mechanical properties, not only the production process flow is saved, but the product also has obvious lightweight advantages.

Claims

1. A production line for unidirectional fiber reinforced prepreg, characterized in that: The invention comprises a spinning unit, a fiber processing unit, a gluing unit arranged in sequence, and a plurality of transmission rollers for transmitting fibers arranged between the units, wherein the spinning unit comprises a spinneret provided with a plurality of spinneret holes, the fiber processing unit comprises an arranging roller, and does not comprise a fiber winding device; the spinneret holes on the spinneret are staggered with each other in the axial direction of the arranging roller, and the fiber processing unit is directly connected to the gluing unit.

2. The production line according to claim 1, characterized in that: The arrangement width of the spinneret holes is smaller than the length of the arrangement roller and the transmission roller.

3. The production line according to claim 1, characterized in that: The spinning unit is a cellulose fiber spinning unit, and the spinneret of the cellulose fiber spinning unit is a spinneret; the cellulose fiber spinning unit also includes a coagulation bath, and the arrangement rollers of the fiber processing unit are arranged in the coagulation bath.

4. The production line according to claim 3, characterized in that: The fiber processing unit comprises a fiber washing device.

5. The production line according to claim 4, characterized in that: The fiber processing unit comprises a fiber drying device.

6. The production line according to claim 4, characterized in that: The fiber processing unit includes at least one pair of fiber squeezing rollers and does not include a fiber drying device.

7. The production line according to claim 6, characterized in that: The glue application unit also includes a glue drying device.

8. A method for producing a unidirectional fiber reinforced prepreg, characterized in that: The steps include: (1) Spinning: The spinning device spins multiple fiber filaments through the spinneret holes; (2) Fiber processing: the plurality of fiber monofilaments fall onto the arrangement roller to form a unidirectional fiber thin layer; (3) Gluing: The fiber thin layer is transported to a gluing unit via a conveying roller for gluing to form a continuous strip-shaped prepreg of fiber-reinforced resin.

9. The production method according to claim 8, characterized in that: In the spinning step of step (1), the fiber monofilament is cellulose fiber, and the spinning step of step (1) comprises the following specific steps: (1.1) preparing cellulose pulp into cellulose fiber spinning solution; (1.2) The spinning solution is ejected through the spinneret to form multiple parallel thin streams of solution, which then enter the coagulation bath to form multiple parallel cellulose fibers.

10. A composite material, characterized in that: The prepregs are prepared by stacking and compounding the prepregs obtained by the production line according to any one of claims 1 to 7 or the method according to any one of claims 8 to 9.

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