Apparatus and method for producing a tow prepreg

Abstract

Apparatus for producing a tow prepreg, the apparatus comprising: a spreading roller (103) which adjusts an angle of attack (α) of the supplied fiber; and two or more coating rollers (104) including a first roller (104a) and a second roller (104b) rotating while forming a nip (d 1 ) between the first roller (104a) and the second roller (104b), wherein the fiber fed from the spreading roller (103) passes through the gap (d 1 ) passes between the first roller (104a) and the second roller (104b) to be coated with a resin, a transfer device (105) which displaces the spreading roller (103); and a controller (109) which determines a position (P 1 , P2) of the spreading roller (103) by controlling the transfer device (105), wherein the controller (109) has a data table showing that an angle of attack (α) of the fiber is matched to the resin content, and the angle of attack (α) of the fiber is determined by the data table or directly input into the data table.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an apparatus and a method for manufacturing a tow prepreg, and more particularly to an apparatus and a method for manufacturing a tow prepreg usable as a material of a pressure vessel for a fuel cell vehicle. BACKGROUND

[0002] DE 689 09 661 T2 describes a process for impregnating fibers and an impregnated fiber.

[0003] US 5 607 531 A describes a coating process for fibers.

[0004] DE 10 2015 204 430 A1 describes a process for impregnating fiber rovings with highly reactive resins in the winding process.

[0005] DE 101 47 303 A1 describes a process for producing bearing materials as well as bearing materials produced by this process and the use of the bearing materials.

[0006] A pressure vessel for storing high-pressure gas requires a material that is inherently strong and has the ability to withstand high pressure. To improve the fuel efficiency and performance of a fuel cell vehicle, lightweight construction is particularly important. Using a lightweight and strong carbon fiber composite material is one of the most effective methods for replacing a metal pressure vessel.

[0007] The pressure vessel formed from the composite material is manufactured by a filament winding method. The filament winding method can easily produce a structure with a circular shape or a curve through integral molding and intensively reinforce a fiber in a load-transmitting direction, thereby having an advantage in maximizing the performance of the composite material. The filament winding method is a composite molding method for manufacturing a rotationally symmetric structure by winding a continuous fiber impregnated with resin around a rotating mold (mandrel) shaped like a cylinder and curing the continuous fiber. The filament winding method can employ a wet winding method in which a filament is impregnated while passing it through a resin bath immediately before winding the fiber around the mold, and a dry winding method using tow prepreg.

[0008] In the wet winding process currently applied to most pressure vessel manufacturing processes, the viscosity of the resin must be very low due to the characteristics of the process, which involves impregnating the reinforced fiber with the resin and simultaneously winding it around the mold. Consequently, it is difficult to combine various resins and apply an additive, making it difficult to implement various resin properties. For the same reason, slippage occurs during winding, making it difficult to wind a complex pattern. Furthermore, the fiber arrangement is not uniform, resulting in relatively low fiber reproducibility and reliability. Furthermore, the use of a liquid resin contaminates a work area, creating a poor manufacturing environment.Furthermore, since the impregnation of the reinforced fiber and resin is carried out at a pressure vessel production site, it is difficult to uniformly adjust a volume ratio of the reinforced fiber and resin, and a defect in a volume ratio product quality may cause a defect of the pressure vessel itself.

[0009] Meanwhile, the dry winding method uses a tow prepreg as an intermediate in such a way that a reinforced fiber is impregnated with a resin at a predetermined volume ratio in advance. By using the tow prepreg, a separate process for impregnating a resin can be omitted, making it possible to manufacture a pressure vessel with a simple and clean process. Furthermore, since the intermediate is produced in advance with an accurate volume ratio, it is possible to prevent a volume ratio defect from being caused in the pressure vessel. Since a resin with a higher viscosity than that used in the wet winding process is used, a surface of the tow prepreg can exhibit adhesion.It exhibits adhesive properties, and the lower mandrel and the surface of the wound tow prepreg can be bonded, thereby preventing resin slippage during winding and allowing for the precise manufacture of the pressure vessel, which can be designed in various patterns. For the reasons described above, tow prepreg has attracted attention as a core material for the next generation of composite pressure vessels.

[0010] A process for producing the tow prepreg is divided into a solvent process and a hot melt process.

[0011] The solvent process is a process of imparting fluidity to the resin by diluting a resin with a high viscosity in a solvent that can melt the resin, impregnating the reinforced fiber with the resin, immersing the diluted resin in the reinforced fiber, and then drying and removing the solvent to produce the tow prepreg. The manufacturing process is simple. However, with the solvent process, it is difficult to precisely control the volume ratio of the resin to the reinforced fiber of the tow prepreg, so complete removal of a volatile substance within the tow prepreg during the drying process is indeed difficult.The residual volatile matter within the tow prepreg is gasified during a molding / curing process to form a void, thereby causing a problem that a performance of a molded product is significantly lowered, and for this reason, the tow prepreg prepared by the solvent process is hardly applied to a high-performance composite material including a high-pressure vessel.

[0012] On the other hand, the hot-melt process is a method for generating fluidity by heating a resin with high viscosity and immersing or impregnating the resin into the reinforced fiber, and therefore, it is possible to produce a tow prepreg with few volatiles. Consequently, the hot-melt process can precisely control a volume ratio of the resin and the reinforced fiber and is therefore a manufacturing process suitable for producing a tow prepreg applicable to a composite product requiring high reproducibility, reliability, and performance. However, at present, no standard has been established for the manufacturing technology of the tow prepreg to which the hot-melt process is applied, and research and development is limited. Furthermore, it is known that the production efficiency of a manufacturing company using a tow prepreg manufactured by hot-melt is low.Hot-melt tow prepreg is commercialized, and for this reason, the material's price is very high, making it difficult to seriously apply tow prepreg to the mass production of composite products. Therefore, the development of a facility and process for precisely and efficiently manufacturing tow prepreg is urgently needed.

[0013] In the related art, to manufacture a tow prepreg using the hot-melt process, a prepreg slitting method and a resin film transfer method are used, which are the existing hot-melt prepreg manufacturing methods.

[0014] The prepreg slitting method is a method for producing a tow prepreg by slitting a previously prepared prepreg with a long width of 200 to 1,000 mm into a prepreg with a desired width and then rewinding the prepreg. The equipment required for production is inexpensive, and the manufacturing process is also relatively simple. However, since a fiber is damaged during the prepreg slitting process, a single yarn may be generated at a boundary or edge of the produced tow prepreg, making it difficult to expect high performance when the tow prepreg is applied to a molded product.

[0015] The resin transfer method has an advantage in that it is possible to precisely control resin contents, but a manufacturing process thereof, which has many steps, is complex and a facility for the manufacturing process is costly.

[0016] Since a sub-material such as a release paper and a release film is used during the production of the tow prepreg, the production cost of a product increases, thereby weakening the price competitiveness of a composite material using the tow prepreg.

[0017] For the reasons mentioned above, there is a need to develop a process for producing a tow prepreg using a direct coating method that minimizes fiber damage, simplifies production equipment and the manufacturing process, and eliminates the use of sub-material. The direct coating method is a process for producing a tow prepreg in which a reinforced fiber directly contacts a hot-melt resin and is impregnated with the resin, without a separate film-coating process or prepreg manufacturing process. A coating technology capable of minimizing single yarn of the reinforced fiber within a short time is at the core of the process.

[0018] For example, in U.S. Patent Application Publication No. 2012-0251823 (hereinafter, Patent 823), resin impregnation between carbon fiber strands is performed by controlling the amount of resin applied to the carbon fiber by adjusting a gap between two coating rolls formed of a metal material capable of heating a resin supplied to a coating zone, and then imparting fluidity to the resin by applying high-temperature heat for a short time, during which the resin passes through an immersion zone. Then, a width of the resin-impregnated carbon fiber is controlled using a cooling roll in a cooling zone, and an appropriate viscosity is imparted to complete and manufacture the tow prepreg.

[0019] To adjust the resin content of the tow prepreg, the '823 patent proposes a method for controlling the gap between two coating rolls, but precise adjustment of the resin content using only two coating rolls is difficult. In particular, when a tow prepreg is manufactured with a small amount of resin, the gap between the two coating rolls needs to be significantly narrowed. In this case, excessive pressure is applied to the carbon fiber positioned between the metal rolls, causing the carbon fiber to be broken and separated. Furthermore, when a tow prepreg is manufactured with a small amount of resin, the gap between the coating rolls is small, and consequently, the amount of resin passing through the coating roll is small, preventing the resin from sufficiently permeating the gap between the carbon fiber strands.Therefore, it is necessary to promote resin immersion by increasing the temperature of a resin immersion zone or extending the length of a section. However, a curing agent is mixed into the resin for the tow prepreg, so if the temperature is excessively high and the exposure time to the high temperature is extended, there is a problem that curing will begin.

[0020] The above-mentioned information disclosed in this Background section is intended only to enhance the understanding of the background of the invention and may therefore contain information that does not constitute prior art already known to someone of ordinary skill in the art in this country. SUMMARY

[0021] The present disclosure has been made in an effort to solve the above-described problems associated with the prior art and to provide an apparatus and a method for manufacturing a tow prepreg, which set a control factor for controlling the resin content of a tow prepreg and vary the control factor, thereby precisely controlling the respective resin content of the tow prepreg and preventing damage such as single yarn and thermal damage to a product.

[0022] The present invention provides an apparatus for producing a tow prepreg having the features of claim 1, and a method for producing a tow prepreg having the features of claim 13.

[0023] According to the present invention, there is provided an apparatus for producing a tow prepreg, the apparatus including: a spreader roll that adjusts an angle of attack of a fed fiber; and two or more coating rolls including a first roll and a second roll that rotate while having a nip between the first roll and the second roll, wherein the fiber fed from the spreader roll passes through the nip between the first roll and the second roll to be coated with a resin. The apparatus further comprises: a transfer device that displaces the spreading roller; and a controller that adjusts a position of the spreading roller by controlling the transfer device, wherein the controller has a data table showing that a pitch angle of the fiber is matched with the content of the resin, and the pitch angle of the fiber is determined by the data table or directly inputted into the data table.

[0024] In a preferred embodiment, the spreading roller can be designed to be adjustable such that a mounting position of the spreading roller is changed.

[0025] In another preferred embodiment, the spreading roller can be adjustable between a first position in which the fiber is fed vertically to the gap between the first roller and the second roller and a second position in which a predetermined maximum angle of attack is formed, and can be fixed in an adjusted position.

[0026] In yet another preferred embodiment, the spreading roller can adjust an angle of attack of the fiber from 0° to 30°.

[0027] In yet another preferred embodiment, the first roller and the second roller may be formed from different materials and either the first roller or the second roller may have a surface formed from an elastic material.

[0028] In yet another preferred embodiment, either the first roller or the second roller may have a surface formed of a non-elastic material, except for the roller having a surface formed of an elastic material.

[0029] In a further preferred embodiment, the device may further include a third roller forming a nip between the second roller and the third roller, wherein the fiber passes through the nip between the second roller and the third roller, and the third roller may have a surface formed of a same material as a material of the surface of the first roller.

[0030] In another further preferred embodiment, the material of the surfaces of the first roller and the third roller may be rubber and the material of the surface of the second roller may be metal.

[0031] In yet another further preferred embodiment, the material of the surfaces of the first roller and the third roller may be metal and the material of the surface of the second roller may be rubber.

[0032] In yet another further preferred embodiment, the gap between the first roller and the second roller may be larger than the gap between the second roller and the third roller.

[0033] In yet another preferred embodiment, the apparatus may further include: a creel around which the fiber is wound so that the fiber is fed to the spreader roller; and a guide roller installed between the creel and the spreader roller to guide the feed of the fiber.

[0034] In yet another preferred embodiment, the apparatus may further include: a heating device that heats the fiber passing through the two or more coating rolls; a cooling roll that cools the fiber passing through the heating device; and a winding device that winds the fiber passing through the cooling roll.

[0035] In another aspect, the present disclosure provides a method for producing a tow prepreg, the method including: a step A of setting an angle of the fiber fed from a spreader roll to two or more coating rolls including a first roll and a second roll; a step B of adjusting the spreader roll according to the set angle of attack; and a step C of feeding the fiber to the two or more coating rolls to continuously coat the fed fiber with resin.

[0036] In a preferred embodiment, the angle of incidence of the fiber can be set from 0° to 30°.

[0037] In another preferred embodiment, step A of determining a pitch angle of the fiber may include inputting resin content data to a controller, and the controller may determine the pitch angle of the fiber according to the data table showing that the pitch angle of the fiber is matched to the resin content.

[0038] In yet another preferred embodiment, the step C of feeding the fiber to the two or more coating rolls and continuously coating the fed fiber with a resin may include feeding the resin to a nip between the first roll and the second roll formed of different materials and coating the fiber passing through the nip with the resin.

[0039] In yet another preferred embodiment, the method may further include removing a portion of the coated resin to reduce the resin content by passing the coated resin through a nip between the second roll and a third roll formed of different materials.

[0040] In yet another preferred embodiment, the method may further include heating the applied resin.

[0041] In another preferred embodiment, the method may further include cooling and wrapping the applied resin.

[0042] The apparatus and method for manufacturing a tow prepreg according to the exemplary embodiments of the present disclosure have the effects described below.

[0043] First, the gap between the first and second rollers is independent of the gap between the second and third rollers, so that even when a tow prepreg with the small amount of resin is produced, the sufficient amount of resin is first coated between the strands of the carbon fiber by enlarging the gap between the first and second rollers, and then the resin is compressed by the second and third coating rollers while the desired amount of resin is separated, thereby producing a tow prepreg with the high degree of immersion with the small amount of resin.

[0044] Secondly, it is possible to uniformly apply and impregnate the resin by the coating rollers and shorten an additional heat treatment time by the heating device, thereby minimizing thermal damage to the resin of the tow prepreg and improving a shelf life and performance of a product.

[0045] Thirdly, in the case of the rubber and metal coating rolls, even if a gap between the coating rolls is 0, no single yarn is produced, so it is possible to produce a tow prepreg with the low resin content (20 to 25%).

[0046] Fourthly, it is possible to adjust the degree of spreading of the carbon fiber fed to the coating roller by adjusting a position and an angle of the spreading roller, thereby continuously producing a tow prepreg with a high impregnation degree and slight single yarns.

[0047] Fifth, it is possible to adjust the resin content of the tow prepreg by adjusting a gap between the two adjacent coating rolls and adjusting the applied resin amount by adjusting a position of the spreader roll, thereby controlling the resin amount of the tow prepreg more precisely.

[0048] Other aspects and preferred embodiments of the invention are discussed below.

[0049] It is to be understood that the term "vehicle" or "vehicular" or other similar term used herein includes motor vehicles in general, such as passenger cars, including off-road vehicles (SUVs), buses, trucks, various business cars, watercraft, including a variety of boats and vessels, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., fuels derived from feedstocks other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more power sources, such as both gasoline-powered and electric-powered vehicles.

[0050] The above-mentioned and other features of the invention are discussed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The above-mentioned and other features of the present disclosure will now be described in detail with reference to certain exemplary embodiments thereof, which are illustrated in the accompanying drawings, which are given below for illustrative purposes only and thus do not limit the present disclosure, and in which: Fig. 1 is a diagram illustrating an apparatus for manufacturing a tow prepreg according to an exemplary embodiment of the present disclosure; Fig. 2 is a diagram illustrating only configurations of a spreading portion and a coating portion formed from Fig. 1 are taken; Fig. 3A is a diagram illustrating a configuration of a coating roller according to an exemplary embodiment of the present disclosure; Fig.3B is a diagram illustrating a configuration of a coating roller according to another exemplary embodiment of the present disclosure; and Fig. 4 is a diagram illustrating a method of manufacturing a tow prepreg according to the present disclosure.

[0052] It should be understood that the accompanying drawings are not necessarily to scale and present a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific embodiments of the present disclosure disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes, will be determined in part by the particular intended application and environment of use.

[0053] In the figures, reference numerals refer to like or equivalent parts of the present invention throughout the several figures of the drawing. DETAILED DESCRIPTION

[0054] Reference will now be made in detail to various embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings and described below. While the invention will be described in connection with exemplary embodiments, it will be understood that the present description is not intended to limit the invention to these exemplary embodiments. On the contrary, the invention is intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents, and other embodiments that may be included within the spirit and scope of the invention as defined by the appended claims.

[0055] The present disclosure sets forth an apparatus and a method for manufacturing a tow prepreg, in which an angle of incidence of a fiber supplied for immersing a resin is adjusted to adjust a tension applied to the fiber supplied to a coating roll, thereby adjusting the resin content. An object of the present disclosure is to manufacture a tow prepreg, and the present disclosure is made on the basis that a carbon fiber is impregnated with resin. However, within a range without departing from the principle of the present disclosure, the present disclosure may be extended to the case where another fiber is impregnated with a resin.

[0056] An example described with reference to the accompanying drawings is an exemplary embodiment, and a configuration of the manufacturing facility is not limited to the illustrated example. Therefore, the invention described in the claims is not limited to the illustrated exemplary embodiment, and one skilled in the art can understand that this should be interpreted as including examples in which the number and arrangement of the rollers, and an arrangement of processes, and the like are appropriately changed.

[0057] Hereinafter, an apparatus and a method for manufacturing a tow prepreg according to an exemplary embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0058] As in Fig.1, an apparatus for manufacturing a tow prepreg according to an exemplary embodiment of the present disclosure is divided into a fiber supply section for supplying a resin, a resin dipping section for dipping the resin into the supplied fiber, a cooling section for cooling the fiber impregnated with the resin and completing a shape of the fiber, and a winding section for completing the wound tow prepreg.

[0059] In the fiber supply section, a fiber such as a carbon fiber is wound, and a creel 101 that supplies the fiber into a device for immersing a resin into the fiber, and a spreader roller 103 for adjusting an angle of incidence α of the supplied fiber are included. As shown in Fig.1, a plurality of guide rollers 102a and 102b for guiding the supplied fiber may be further installed between the creel 101 and the spreader roller 103.

[0060] The spreading roller 103 may be installed at a straight front end of a coating roller 104 and configured such that an angle of attack α of the fiber supplied to the coating roller 104 is changed according to a position change of a position of the spreading roller 103.

[0061] Meanwhile, in the resin dipping section, at least two coating rollers 104 are provided, including a first roller 104a and a second roller 104b, which rotate while having a gap between them through which the fiber fed from the spreading roller passes. As shown in Fig.1, the nip is formed between the first roller 104a and the second roller 104b, and the resin is supplied to an upper side of the nip. Consequently, when the fiber is supplied to the nip between the first roller 104a and the second roller 104b by the spreading roller 103, a hot-melt resin is preferably supplied to a space formed by the first roller 104a and the second roller 104b in an upper region of the nip, that is, an upper portion of the nip.

[0062] Therefore, the hot-melt resin is preferably supplied by a resin supply unit (not illustrated) before the fiber is supplied to the coating roller 104, so that the fiber passing through the coating roller 104 can be coated with the resin. Furthermore, the present disclosure further includes a heater 106 for supplying heat to the fiber in the resin dipping section for additional impregnation with the resin.

[0063] The fiber passing through the resin dipping section is cooled while passing through the cooling roller 107 of the cooling section to have a finished shape. Then, the cooled fiber is wound around a tube by a winding device 108 through a guide roller 102c at a rear end of the line to complete the tow prepreg.

[0064] Meanwhile, Fig. 2 is an enlarged view of an adjacent portion of the spreading roller 103 and the coating roller 104 in the fiber supply section and the resin dipping section in the exemplary embodiment of the Fig. 1

[0065] If the carbon fiber unwound from the creel 101 directly enters the resin dipping section for coating with the resin and immersing it without spreading, the resin is likely to be applied only to one surface of the carbon fiber. This may cause a dipping defect in the tow prepreg, so that the strands of the carbon fiber fed to the coating roller 104 may be spread in advance.In the related art, for spreading the carbon fiber, a method of making the carbon fiber pass alternately through the plurality of concave or convex rollers or a method of mechanically shaking the carbon fiber is used, but a curvature is set at each roller in the process using the roller, so that it is difficult to respond to a change in a production condition, and the carbon fiber is damaged due to friction in the process of mechanically shaking the carbon fiber, so that a property of the tow prepreg may be degraded.

[0066] Meanwhile, the present disclosure is characterized in that the spreading roller 103 is designed to be movable and a position of the spreading roller 103 is changed. As in Fig.2, an angle of attack α of the carbon fiber can be adjusted according to an adjustment of the spreading roller 103, thereby adjusting a tension applied to the carbon fiber.

[0067] In the exemplary embodiment of the present disclosure, the present disclosure further includes a transfer device 105 for adjusting the spreading roller 103, and a controller 109, which is an electrical circuit that executes instructions of software, thereby performing various functions for adjusting a position of the spreading roller 103 by controlling the transfer device 105. In this case, the controller 109 includes a data table showing that a fiber pitch angle α is matched to the resin content, and the fiber pitch angle α can be determined from the data table, or an operator can directly input the fiber pitch angle α.

[0068] Consequently, the operator inputs the angle of attack α or the resin content of the fiber so that the degree of spreading of the carbon fiber introduced into the coating roller 104 can be continuously controlled.

[0069] In particular, a principle for adjusting the spreading degree is described below. If it is assumed that a tension applied to the carbon fiber (i.e., the fiber formed by the force applied at a position P 1 arranged spreading roller and in Fig. 2 is indicated by a dotted line) passing vertically through the gap between the two coating rollers (the first roller and the second roller) actuated by a predetermined torque, F 1 has a voltage F 2 , which is attached to the carbon fiber (that is, the fiber formed by the at P 2 arranged spreading roller and with a solid line in Fig.2) when an angle of attack is set by α, has a relationship described below. F2=F1 / sinα(0≤α≤90°)

[0070] Consequently, the tension applied to the fiber can be adjusted according to the setting of the angle of attack α, and the amount of resin impregnated can be adjusted according to the tension applied to the fiber. In particular, when the tension applied to the fiber is low, the carbon fiber, along with the resin, is easily pressed and spread as it passes through the gap between the two coating rolls, thereby allowing the resin to be evenly immersed between the fibers. Meanwhile, when the tension applied to the carbon fiber is high, the fiber is not easily spread, and the amount of resin applied to the fiber is reduced, thereby producing a product with a low resin content.

[0071] The spreading roller 103 is between the first position P 1 , at which the fiber is vertically fed to the gap between the first roller 104a and the second roller 104b, and the second position P 2 adjustable, at which the fiber can form a predetermined maximum angle of attack α, and can be fixed at an adjusted position.

[0072] In this case, a preferable angle of attack α of the fiber is 0≤α<30°, and when the angle of attack α is 30° or more, the fiber is pulled by a high tension and thickly collected, so that the fiber may be damaged when it passes through the narrow gap between the coating rolls.

[0073] Meanwhile, the carbon fiber spread by the spreading roller 103 passes through the two or more coating rollers 104 including the first roller 104a and the second roller 104b positioned at a rear end of the equipment.

[0074] The first roller 104a and the second roller 104b are formed of different materials, and a surface of the first roller 104a or the second roller 104b is formed of an elastic material. Herein, the reason why the first roller 104a or the second roller 104b is formed to have an elastic surface is to narrow a gap between the first roller 104a and the second roller 104b. For example, when the carbon fiber passes through the gap between the coating rollers formed of a non-elastic metal, the carbon fiber can be broken by the hard coating roller, and a single yarn can be produced.However, in the case of the roll whose surface is formed of the elastic material, even if a gap between the two coating rolls is set to be very small, a single yarn is hardly produced when the carbon fiber passes through the gap, so that it is possible to produce a tow prepreg with the low resin content compared with that of the metal-to-metal rolls.

[0075] In this case, the material of the surface of the coating roller 104 may be set such that rubber and metal are arranged alternately. For example, the arrangement of the coating rollers may be as shown in the Fig. 3A and Fig. 3B, the metal-rubber-metal coating rolls or the rubber-metal-rubber coating rolls, and in consideration of productivity, the metal-rubber-metal rolls may be more preferable for shortening a heating time.

[0076] The first roller 104a and the second roller 104b, which are the two front rollers among the plurality of coating rollers, sufficiently supply the resin, and the resin is compressed by the rear rollers, that is, the second roller 104b and the third roller 104c, so that even when producing a tow prepreg with a low resin content, it is possible to supply a sufficient amount of resin between the fiber strands at an initial stage. However, friction between the roller and the fiber during passage through the gaps between the plurality of rollers may damage the fiber, so the use of three or fewer rollers is preferred.

[0077] A gap d 1 between the first roller 104a and the second roller 104b may be set to be larger than a gap d 2between the second roller 104b and the third roller 104c. The applied resin passing through the first gap between the first roller 104a and the second roller 104b passes through a narrower gap formed between the second roller 104b and the third roller 104c, so that the applied resin is compressed to reduce the resin content.

[0078] The gap between the first roller 104a and the second roller 104b and the gap formed between the second roller 104b and the third roller 104c can be adjusted by an operator as needed. For this purpose, the present disclosure may include a drive unit capable of changing a position of the roller to adjust the gaps between the respective rollers or the gaps of at least some rollers. Consequently, it is possible to adjust the resin content by adjusting the gaps between the respective rollers by the drive unit together with controlling the setting angle α by the spreader roller 103. In this case, regarding the data table included in the controller 109, the plurality of data tables may be included according to the gap between the rollers.

[0079] Table 1 below contains data based on which it can be recognized that the resin content of the tow prepreg is changed according to an adjustment of an angle of attack α with respect to the carbon fiber. [Table 1] Angle of attack (α) Resin content 1 0° 32,3% 2 10° 31,8% 3 15° 31,1% 4 20° 30,1% 5 25° 28,9% 6 30° 27,2% (Gap between the first roller and the second roller: 0.2 mm, gap between the second roller and the third roller: 0.135 mm, β=220 mm) [Table 2] Gap between the second roller and third roller Resin content 1 0.135 mm 30,1% 2 0 23,4% (Angle of attack (α): 20°, gap between the first roller and the second roller: 0.2 mm)

[0080] Meanwhile, Fig. 4 is a diagram illustrating an example of a method for manufacturing a tow prepreg according to an exemplary embodiment of the present disclosure.

[0081] As in Fig.4, the method for manufacturing a tow prepreg according to the exemplary embodiment of the present disclosure includes: adjusting an angle of attack α of the fiber (S501), injecting the fiber into coating rolls (S502), coating the fiber with resin and immersing the resin (S503), passing the fiber to a cooling roll and fixing a shape of the fiber (S504), and winding the fiber impregnated with the resin, and finally completing the tow prepreg (S505).

[0082] Adjusting the angle of attack α of the fiber (S501) may specifically include setting an angle of attack α of the fiber supplied to the coating rollers from the spreader roller 103 and adjusting the spreader roller according to the set angle of attack α. After the angle of attack α is adjusted as described above, the fiber is supplied to the coating rollers, and the supplied fiber is continuously coated with the resin.

[0083] In this case, setting the fiber pitch angle α includes inputting resin content data to the controller 109, and the controller 109 can determine the fiber pitch angle α according to the data table showing that the fiber pitch angle α is matched with the resin content.

[0084] When applying the resin, the resin is supplied to the nip between the first roller and the second roller so that the fiber passing through the nip is first coated with the resin, and the applied resin passes through the nip between the second roller and the third roller so that part of the applied resin is removed and the resin content is reduced.

[0085] Although it will not be in Fig. 4, but, as described above, the method may further include additionally immersing the resin in a non-contact process by heating the applied resin. [Example 1]

[0086] A carbon fiber was mounted in the creel 101, the fiber was unwound, and the fiber passed through the rollers in the fiber feeding section, where the rollers were heated to 80°C to heat and spread the carbon fiber.

[0087] In order to produce a tow prepreg which is generally used and has a resin content of 30%, a width of the fiber passing through the spreader roll was controlled such that α is 20°.

[0088] The fiber passes through a nip between a first roller (metal) and a second roller (rubber) heated to 80°C. In this case, a gap between the two coating rollers was set to 0.2 mm so that the resin would be sufficiently coated between the strands of the carbon fiber. Next, a gap between the second roller and the third roller, heated to 80°C, was set to 0.135 mm. In this case, taking into account an influence of resin flow, the gap between the second roller and the third roller was adjusted to maintain a width of the fiber passing through the nip between the second and third rollers at 1.5 mm. An additional immersion used a heater spaced 50 mm from the fiber using a non-contact method.In this case, the heat source temperature was set to 130°C, and the heat source length was set to 500 mm (considering a production speed of 10 mm per minute). To complete the molding, the resin-impregnated carbon fiber passed through the gap between the chill rolls set at 10°C. The gap between the chill rolls was adjusted to a desired width by adjusting the tension applied to the fiber. The fiber was wound around a tube by a winding device to complete the tow prepreg.

[0089] The invention has been described in detail with reference to preferred embodiments thereof. However, one skilled in the art will appreciate that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and equivalents thereof.

Claims

[1] Apparatus for producing a tow prepreg, the apparatus comprising: a spreading roller (103) which adjusts an angle of attack (α) of the supplied fiber; and two or more coating rollers (104) including a first roller (104a) and a second roller (104b) rotating while forming a nip (d 1 ) between the first roller (104a) and the second roller (104b), wherein the fiber fed from the spreading roller (103) passes through the gap (d 1 ) passes between the first roller (104a) and the second roller (104b) to be coated with a resin, a transfer device (105) which displaces the spreading roller (103); and a controller (109) which determines a position (P 1 , P2) of the spreading roller (103) by controlling the transfer device (105), wherein the controller (109) has a data table showing that an angle of attack (α) of the fiber is matched to the resin content, and the angle of attack (α) of the fiber is determined by the data table or directly input into the data table. [2] The device according to claim 1, wherein the spreading roller (103) is designed to be adjustable so that a mounting position of the spreading roller (103) is changed. [3] Device according to claim 2, wherein the spreading roller (103) is movable between a first position (P 1 ), in which the fiber faces the gap (d 1 ) between the first roller (104a) and the second roller (104b) is fed vertically, and a second position (P 2 ), in which a predetermined maximum angle of attack (α) is formed, is adjustable and is fixed in an adjusted position. [4] Device according to claim 1, wherein the spreading roller (103) sets an angle of attack (α) of the fiber from 0° to 30°. [5] The device according to claim 1, wherein the first roller (104a) and the second roller (104b) are formed of different materials and either the first roller (104a) or the second roller (104b) has a surface formed of an elastic material. [6] The device according to claim 5, wherein either the first roller (104a) or the second roller (104b) has a surface formed of a non-elastic material except for the roller having a surface formed of an elastic material. [7] Device according to claim 5, further comprising: a third roller which has a gap (d 2 ) between the second roller (104b) and the third roller (104c), wherein the fiber passes through the gap (d 2) between the second roller (104b) and the third roller (104c), wherein the third roller (104c) has a surface formed of a same material as a material of the surface of the first roller (104a). [8] The device according to claim 7, wherein the material of the surfaces of the first roller and the third roller is rubber and the material of the surface of the second roller is metal. [9] The device according to claim 7, wherein the material of the surfaces of the first roller and the third roller is metal and the material of the surface of the second roller is rubber. [10] Device according to claim 7, wherein the gap (d 1 ) between the first roller (104a) and the second roller (104b) is greater than the gap (d 2 ) between the second roller (104b) and the third roller (104c). [11] Device according to claim 1, further comprising: a creel (101) around which the fiber is wound such that the fiber is fed to the spreading roller (103); and a guide roller (102a; 102b) installed between the creel (101) and the spreader roller (103) to guide the supply of the fiber. [12] Device according to claim 1, further comprising: a heating device that heats the fiber passing through the two or more coating rollers (104); a cooling roller (107) which cools the fiber passing through the heating device; and a winding device (108) which winds the fiber passing through the cooling roller (107). [13] A method of manufacturing a tow prepreg, the method comprising: a step A of setting an angle of attack (α) of the fiber fed from a spreading roller (103) to two or more coating rollers (104) including a first roller (104a) and a second roller (104b); a step B for adjusting the spreading roller (103) according to the specified angle of attack (α); and a step C of feeding the fiber to the two or more coating rolls (104) and continuously coating the fed fiber with a resin. [14] Method according to claim 13, wherein the angle of incidence (α) of the fiber is set from 0° to 30°. [15] The method of claim 13, wherein step A of determining an angle of attack (α) of the fiber includes inputting resin content data to a controller (109), and the controller (109) determines the angle of attack (α) of the fiber according to a data table showing that the angle of attack (α) of the fiber is matched to the resin content. [16] The method of claim 13, wherein the step C of feeding the fiber to the two or more coating rolls (104) and continuously coating the fed fiber with a resin comprises feeding the resin to a nip (d 1 ) between the first roller (104a) and the second roller (104b), which are formed of different materials, and coating the fiber passing through the gap (d 1 ) containing the resin. [17] The method of claim 16, further comprising: Removing a portion of the applied resin to reduce the resin content by passing the applied resin through a gap (d 2 ) between the second roller and a third roller made of different materials. [18] The method of claim 13, further comprising: Heating the applied resin. [19] The method of claim 13, further comprising: Cooling and wrapping the applied resin.

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