JPWO2020040155A1 - Prepreg manufacturing method, prepreg tape manufacturing method and fiber reinforced composite material manufacturing method - Google Patents

Abstract

The present invention relates to a method for producing a prepreg in which a matrix resin is applied to a reinforcing fiber sheet, so that continuous running is possible without clogging of generated fluff even when the traveling speed is high, and the reinforcing fiber sheet is efficiently impregnated with the matrix resin. An object of the present invention is to provide a method for producing a prepreg, which enables the matrix resin (2) to be passed through a reinforcing fiber sheet (1a) inside a coating portion (20) in which the matrix resin (2) is stored. Is applied to the reinforcing fiber sheet (1a), and then spray coating or curtain coating is performed to further discharge the liquid onto the primary prepreg (1c) drawn from the coating portion (20). The portion (20) includes a liquid pool portion and a constricted portion that are communicated with each other, and the liquid pool portion has a portion in which the cross-sectional area continuously decreases along the traveling direction of the reinforcing fiber sheet (1a), and the constriction portion. A method for manufacturing a prepreg, wherein the portion has a slit-shaped cross section and has a cross-sectional area smaller than that of the upper surface of the liquid pool portion.

Description

The present invention relates to a method for producing a prepreg, and more particularly to a method for uniformly impregnating a reinforcing fiber sheet with a matrix resin.

Fiber reinforced composite materials (FRP), which are matrix resins containing thermoplastics and thermosetting resins reinforced with reinforcing fibers, are used for aerospace materials, automobile materials, industrial materials, pressure vessels, building materials, housings, and medical care. It is used in various fields such as applications and sports applications. Carbon fiber reinforced composite materials (CFRP) are widely and preferably used, especially when high mechanical properties and light weight are required. On the other hand, when cost is prioritized over mechanical properties and light weight, glass fiber reinforced composite material (GFRP) may be used. In FRP, a reinforcing fiber bundle is impregnated with a matrix resin to obtain an intermediate base material, which is laminated and molded, and when a thermosetting resin is used, it is heat-cured to manufacture a member made of FRP. In the above applications, there are many flat objects and bent forms thereof, and as an intermediate base material for FRP, a two-dimensional sheet-like object is used for manufacturing a member rather than a one-dimensional strand or a roving-like object. It is widely used from the viewpoint of stacking efficiency and moldability.

Further, recently, in order to improve the production efficiency of a member made of FRP, mechanization and automation of laminating sheet-shaped intermediate base materials have been promoted, and narrow tape-shaped intermediate base materials are preferably used here. The narrow tape-shaped intermediate base material can be obtained by slicing a wide sheet-shaped intermediate base material to a desired width, or by directly impregnating a narrow-width reinforcing fiber sheet with a matrix resin.

A prepreg is generally used as a two-dimensional sheet-like intermediate base material. The prepreg is produced by applying and impregnating a matrix resin to reinforcing fibers. As the reinforcing fiber sheet, a unidirectional material (UD base material) in which a plurality of reinforcing fibers are arranged on a surface in one direction, or a reinforcing fiber in which reinforcing fibers are arranged in multiple axes or randomly arranged to form a sheet is used. There is a fabric.

The hot melt method, which is one of the prepreg manufacturing methods, melts the matrix resin, coats it on a release paper, creates a laminated structure sandwiched between the upper and lower surfaces of the reinforcing fiber sheet, and then heats and pressures it. The matrix resin is impregnated inside the reinforcing fiber sheet. This method has a problem that the number of steps is large, the production speed cannot be increased, and the cost is high.

As for the efficiency of impregnation, for example, there has been a proposal as in Patent Document 1. This was a method in which glass fibers were melt-spun and bundled into strands or rovings and passed through a liquid pool having a conical flow path filled with a thermoplastic resin.

On the other hand, Patent Document 2 describes a method of forming a coating film on both sides of a sheet-like material at the same time. In order to prevent the sheet-like material from fluctuating during coating film formation, the sheet-like material is passed through a web guide. After that, it is painted with a pipe type doctor.

As a method for manufacturing a strip-shaped prepreg using a thermoplastic resin, a horizontal drawing method (horizontal drawing method) in which a strip-shaped reinforcing fiber bundle is transported in the horizontal direction (horizontal direction), passed through a die, and the thermoplastic resin is applied / impregnated to the strip-shaped reinforcing fiber bundle. Patent Document 3) is known. In Patent Document 3, a plurality of strip-shaped reinforcing fiber bundles are separately introduced into a die filled with a molten thermoplastic resin, and the fibers are opened, impregnated, and laminated by a fixing guide (for example, a squeeze bar), and finally 1 It is described that it is pulled out from the die as a sheet-shaped prepreg.

Patent Document 4 describes a device in which a manifold is filled with a thermoplastic resin and ultrasonic vibration is applied to an outlet in a pull-fusion method in which a reinforcing fiber bundle is vertically pulled out.

Further, Patent Document 5 describes that a thermoplastic resin is sprayed on a carbon fiber sheet by using a so-called melt blow method. Further, Comparative Example 1 of Patent Document 5 describes that a film slit die is used on a carbon fiber sheet and PPS (polyphenylene sulfide), which is a thermoplastic resin, is laminated.

International Publication WO2001 / 028951 Pamphlet Japanese Unexamined Patent Publication No. 10-337516 International Publication WO2012 / 00217 Pamphlet Japanese Unexamined Patent Publication No. 1-178412 International Publication WO2003 / 091015 Pamphlet

However, the method of Patent Document 1 can only produce strands and roving-like products, and cannot be applied to the production of sheet-shaped prepregs that are the subject of the present invention. Further, in Patent Document 1, in order to improve the impregnation efficiency, a fluid of a thermoplastic resin is applied to the side surface of the strand or the roving-like reinforcing fiber bundle to positively generate turbulence in the conical flow path. It is considered that this is intended to partially disturb the arrangement of the reinforcing fiber bundles and allow the matrix resin to flow in. However, when this idea is applied to the reinforcing fiber sheet, the reinforcing fiber sheet is deformed and the quality of the prepreg is deteriorated. It is considered that not only the mechanical properties of FRP are lowered, but also the mechanical properties of FRP are lowered.

Further, when the technique of Patent Document 2 is applied, it is considered that fluffing occurs due to rubbing with the web guide, which makes it difficult for the reinforcing fiber sheet to run. Further, the technique of Patent Document 2 is resin coating, and impregnation is not intended.

Further, in the method of Patent Document 3, fluff tends to stay in the liquid pool portion during continuous production, and fluff tends to be clogged in the drawn portion. In particular, when the strip-shaped reinforcing fiber bundle is continuously run at a high speed, the frequency of fluff clogging becomes very high, so that the production can be performed only at a very slow speed, and there is a problem that the productivity does not increase. Further, in the case of the horizontal drawing method, the die portion needs to be sealed to prevent liquid leakage, and it is not sufficient to collect fluff during continuous production. Further, in the horizontal drawing method, when the matrix resin is impregnated inside the reinforcing fiber sheet, the air bubbles remaining inside the strip-shaped reinforcing fiber bundle are in a direction orthogonal to the orientation direction of the reinforcing fiber bundle due to buoyancy (belt-shaped reinforcement). Since it is discharged in the direction of the thickness of the fiber bundle), the air bubbles are discharged by pushing away the impregnated matrix resin. Therefore, the movement of bubbles is hindered by the liquid, and the impregnation of the matrix resin is also hindered by the bubbles, so that there is a problem that the impregnation efficiency is poor. Further, it has been proposed to exhaust air bubbles from the vent, but the effect is considered to be limited because it is only near the die outlet.

Further, in the method described in Patent Document 4, a nozzle portion not filled with resin is provided in the upper part of the manifold, and the nozzle can be optimized with a strand or a roving-like material, but a flat surface such as a reinforcing fiber sheet. It is difficult to adapt to the shape, and when the reinforcing fiber sheet passes through it, fluff is generated, and when it is brought into the manifold, it is considered that it is easily clogged with a die.

The method disclosed in Patent Document 5 is inefficient because the matrix resin can be applied to only one side of the carbon fiber sheet.

As described above, an efficient method for applying the matrix resin to the reinforcing fiber sheet, particularly an efficient method for producing the prepreg using the UD base material, has not yet been established.

The subject of the present invention is that, regarding the method for producing a prepreg, fluffing is suppressed, continuous production is possible without clogging of fluff, and a matrix resin is simultaneously applied to both sides of a reinforcing fiber sheet and efficiently impregnated. It is an object of the present invention to provide a method for producing a prepreg, which can increase the production speed, suppress breakage of the obtained prepreg, have a uniform grain size, and have excellent appearance and workability.

In the method for producing a prepreg of the present invention, which solves the above-mentioned problems, a reinforcing fiber sheet is passed through a coating portion in which a matrix resin is stored to apply the matrix resin to the reinforcing fiber sheet, and then from the coating portion. A method for manufacturing a prepreg in which a liquid is further discharged to a drawn primary prepreg by spray coating. The coating portion is provided with a liquid pool portion and a constriction portion which are communicated with each other, and the liquid pool portion is a reinforcing fiber sheet. This is a method for manufacturing a prepreg, which has a portion in which the cross-sectional area continuously decreases along the traveling direction, the constricted portion has a slit-shaped cross section, and has a cross-sectional area smaller than that of the upper surface of the liquid pool portion.

Further, a curtain in which a reinforcing fiber sheet is passed through a coating portion in which the matrix resin is stored to apply the matrix resin to the reinforcing fiber sheet, and then a liquid is further discharged to a primary prepreg drawn from the coating portion. A method for manufacturing a prepreg to be coated, wherein the coated portion is provided with a liquid pool portion and a constricted portion which are communicated with each other, and the cross-sectional area of the liquid pool portion continuously decreases along the traveling direction of the reinforcing fiber sheet. This is a method for producing a prepreg, which has a portion, the narrowed portion has a slit-shaped cross section, and has a cross-sectional area smaller than that of the upper surface of the liquid pool portion.

Further, it is a method of manufacturing a prepreg in which a reinforcing fiber sheet is passed through a coating portion in which a matrix resin is stored to apply the matrix resin to the reinforcing fiber sheet. The liquid pool portion is provided with a narrowed portion, and the liquid pool portion has a portion in which the cross-sectional area continuously decreases along the traveling direction of the reinforcing fiber sheet, and the narrowed portion has a slit-shaped cross section and is from the upper surface of the liquid pool portion. Also has a small cross-sectional area, and before the reinforcing fiber sheet is passed through the inside of the coating part, at least one selected from the group consisting of a thread cracking inhibitor, a toughness improving agent, a flame retardant and a fluff sizing agent on the reinforcing fiber sheet. This is a method for producing a prepreg to which a modifier is applied.

Further, the method for producing a prepreg tape of the present invention is characterized in that the prepreg obtained by the above-mentioned method for producing a prepreg is slit.

Further, the method for producing a fiber-reinforced composite material of the present invention is characterized by molding a prepreg obtained by the method for producing a prepreg or a prepreg tape obtained by the method for producing a prepreg tape.

According to the method for producing a prepreg of the present invention, clogging due to fluff can be significantly suppressed and prevented. Further, the reinforcing fiber sheet can be continuously run at high speed, and the productivity of the prepreg is improved.

Further, in one of the embodiments of the present invention, another substance can be added to the surface of the prepreg, so that the physical properties and functionality of the prepreg and the FRP obtained from the prepreg can be improved. Further, when the same resin as the matrix resin is used instead of the other substance, process stability and quality can be improved.

Further, in another embodiment, since the modifier can be applied to the reinforcing fiber sheet before the matrix resin is applied, the physical characteristics and functionality of the FRP can be improved, and the process stability and quality can be improved. Can be improved.

It is a schematic cross-sectional view which shows the manufacturing method of the prepreg and the coating apparatus which concerns on one Embodiment of 1st manufacturing method of this invention. It is a schematic cross-sectional view which shows the manufacturing method of the prepreg and the coating apparatus which concerns on one Embodiment of the 2nd manufacturing method of this invention. It is a detailed cross-sectional view which enlarged the part of the coating part 20 in FIGS. 1a and 1b. FIG. 2 is a bottom view of the coating portion 20 in FIG. 2 as viewed from the direction A in FIG. 2 is a cross-sectional view illustrating the structure inside the coating portion when the coating portion 20 in FIG. 2 is viewed from the direction B of FIG. 2. It is sectional drawing which shows the flow of the matrix resin 2 in the gap 26 in FIG. 4a. It is a figure which shows the installation example of the width regulation mechanism. It is a detailed cross-sectional view of the coating part 20b of the embodiment different from FIG. It is a detailed cross-sectional view of the coating part 20c of the embodiment different from FIG. It is a detailed cross-sectional view of the coating part 20d of the embodiment different from FIG. It is a detailed cross-sectional view of the coating part 20e of the embodiment different from FIG. It is a detailed cross-sectional view of the coating part 30 of the embodiment different from this invention. It is a figure which shows the mode which provided the bar in the liquid pool part which is an example of embodiment of this invention. It is the schematic which shows the example of the spray coating process used in this invention. It is a schematic diagram explaining the spinning behavior of the discharged liquid and the solidified product when the coating height h is lowered in the spray coating process used in the present invention. It is a schematic diagram explaining the spinning behavior of a discharged liquid and a solidified product thereof when the coating height h is increased in the spray coating process used in the present invention. It is a side view when the coating angle is 90 ° in the curtain coating process used in this invention. It is a side view when the curtain coating apparatus is tilted with the coating angle as α ° in the curtain coating process used in the present invention. It is a front view for demonstrating the state of the edge of a film (in the case of having an air flow control) in the curtain coating process used in this invention. It is the top view which looked at the vicinity of the curtain coating process used in this invention from the top. It is a side view for demonstrating the state of the surface portion of the film of the curtain coating process used in this invention (when there is no airflow control). It is a side view for demonstrating the state of the surface portion of the film of the curtain coating process used in this invention (in the case of having airflow control). It is a side view which shows the example of the curtain coating apparatus used in this invention provided with the control means by an air flow. It is a side view at the time of coating on a roll in the curtain coating process used in this invention. It is a figure which shows the example of the aspect which comprises the simple impregnation apparatus which concerns on one Embodiment of this invention. It is a figure which shows the example of the aspect which comprises a plurality of coating parts which concerns on one Embodiment of this invention. It is a figure which shows the example of the aspect which stacks a plurality of prepregs which concerns on one Embodiment of this invention. It is a figure which shows the example of another aspect which comprises a plurality of coating parts which concerns on one Embodiment of this invention. It is the schematic which shows the example of the prepreg manufacturing process / apparatus which used the 1st manufacturing method of this invention. It is the schematic of the example of another prepreg manufacturing process / apparatus using the 1st manufacturing method of this invention. It is the schematic which shows the example of the prepreg manufacturing process / apparatus which used the 2nd manufacturing method of this invention. It is the schematic which shows the example of the prepreg manufacturing process / apparatus which used the 2nd manufacturing method of this invention. It is the schematic which shows the example of another prepreg manufacturing process / apparatus using the 2nd manufacturing method of this invention. It is the schematic which shows the example of another prepreg manufacturing process / apparatus using the 2nd manufacturing method of this invention. It is the schematic which shows the example of another prepreg manufacturing process / apparatus using the 2nd manufacturing method of this invention. It is the schematic which shows the example of another prepreg manufacturing process / apparatus using the 2nd manufacturing method of this invention. It is the schematic which shows the example of another prepreg manufacturing process / apparatus using the 2nd manufacturing method of this invention. It is the schematic which shows the example which used the spray coating as the modifier applying apparatus in FIG. 29a. It is the schematic which looked at the state of addition of the modifier of FIG. 35a from the direction of M of FIG. 35a. It is the schematic which shows the example which used the melt blow as the modifier applying apparatus in FIG. 29a. It is the schematic which looked at the state of addition of the modifier of FIG. 36a from the direction of M of FIG. 36a. It is the schematic which shows the example which used the curtain coating as the modifier applying apparatus in FIG. 29a. It is the schematic which looked at the state of addition of the modifier of FIG. 37a from the direction of M of FIG. 37a. It is the schematic which shows the example which used the surface coating apparatus as the modifier applying apparatus in FIG. 29a of an embodiment different from FIG. 37a. It is the schematic which looked at the state of addition of the modifier of FIG. 38a from the direction of M of FIG. 38a.

A preferred embodiment of the present invention will be described with reference to the drawings. It should be noted that the following description exemplifies the embodiment of the invention, and the present invention is not construed as being limited to this, and various modifications can be made without departing from the object and effect of the present invention. ..

<Outline of prepreg manufacturing method>
The present invention is characterized by a method of applying the matrix resin to the reinforcing fiber sheet, but further, in order to stabilize this process and improve the functionality and quality of the obtained prepreg, before and after the application / impregnation of the matrix resin, Further, a resin, a modifier, etc. are added.

First, with reference to FIG. 1a, the outline of the first production method of the present invention in which further coating is performed after applying the matrix resin will be described. FIG. 1a is a schematic cross-sectional view showing a prepreg manufacturing method and an apparatus according to an embodiment of the first manufacturing method of the present invention. The coating device 100 is provided between the transport rolls 13 and 14 and the transport rolls 13 and 14, which are traveling mechanisms that allow the reinforcing fiber sheet 1a to travel substantially downward Z in the vertical direction, and stores the matrix resin 2. A plumb bob 20 is provided. Further, before and after the coating device 100, a plurality of creases 11 for unwinding the reinforcing fibers 1 and a reinforcing fiber sheet 1a in which the unwound reinforcing fibers 1 are arranged in one direction (arranged in the depth direction of the paper surface in FIG. 1a). The array device 12 and the winding device 15 of the prepreg 1c can be provided, and the coating device 100 (not shown) is provided with a matrix resin supply device. Further, the supply devices 16a and 16b for supplying the release sheets 3a and 3b are provided. Then, after forming the primary prepreg 1c, the spray coating device 41 and the curtain coating device 42 are arranged. Only one of the spray coating device 41 and the curtain coating device 42 may be used, or both may be used. When both are used, the order of the spray coating device 41 and the curtain coating device 42 can be changed according to the purpose. Further, in FIG. 1a, the spray coating device 41 and the curtain coating device 42 are drawn only on one side of the primary prepreg 1c, but these can be arranged on both sides of the primary prepreg 1c and coated on both sides at the same time. be.

Next, with reference to FIG. 1b, the outline of the second production method of the present invention in which the modifier is applied before the matrix resin is applied will be described. FIG. 1b is a schematic cross-sectional view showing a method of manufacturing a prepreg when a UD base material is used as a reinforcing fiber sheet according to an embodiment of the second manufacturing method of the present invention. The coating device 100 is provided between the transport roll 13 and the transport roll 14, which is a traveling mechanism that allows the reinforcing fiber sheet 1a to travel substantially downward Z in the vertical direction, and stores the matrix resin 2 which is a coating mechanism. A coating portion 20 is provided. Further, before and after the coating device 100, a plurality of creels 11 for unwinding the reinforcing fibers 1 and a reinforcing fiber sheet 1a (paper surface in FIG. 1b) in which the unwound reinforcing fibers 1 are arranged in one direction and used as a UD base material. An arrangement device 12 for obtaining (arrangement in the depth direction), a modifier application device 28 for obtaining a reinforcing fiber sheet 1b to which a modifier is applied, and a winding device 15 for prepreg 1d can be provided, and are not shown. However, the coating device 100 is provided with a matrix resin supply device. Further, if necessary, a release sheet supply device 16 for supplying the release sheet 3 can be provided.

When a reinforcing fiber fabric is used as the reinforcing fiber sheet, a winding device for unwinding the reinforcing fiber fabric is provided in place of the reel 11 in FIGS. 1a and 1b, and a nip roll for pulling out the reinforcing fiber fabric is provided in place of the arranging device 12. A prepreg in which a reinforcing fiber fabric is impregnated with a matrix resin can be produced.

In addition, in FIGS. 1a and 1b, an example of vertically downward direction is shown as a direction in which the reinforcing fiber sheet is passed through the coating portion, but this direction may be a horizontal direction or a direction inclined from the horizontal plane. There may be. When passing in the horizontal direction, it does not necessarily have to be exactly horizontal, and it can be selected from the range of ± 5 ° in the horizontal plane.

<Reinforced fiber sheet>
Here, examples of the reinforcing fibers include carbon fibers, glass fibers, metal fibers, metal oxide fibers, metal nitride fibers, and organic fibers (aramid fibers, polybenzoxazole fibers, polyvinyl alcohol fibers, polyethylene fibers, etc.). However, it is preferable to use carbon fiber from the viewpoint of mechanical properties and light weight of FRP.

As the reinforcing fiber sheet, a unidirectional material (UD base material) in which a plurality of reinforcing fibers are arranged on a surface in one direction, or a reinforcing fiber in which reinforcing fibers are arranged in multiple axes or randomly arranged to form a sheet is used. Fabric is mentioned.

A known method can be used for forming the UD base material, and there is no particular limitation, but a reinforcing fiber bundle in which single fibers are arranged in advance is formed, and the reinforcing fiber bundles are further arranged to form a reinforcing fiber sheet. It is preferable to form the fibers from the viewpoint of process efficiency and arrangement uniformity. For example, in carbon fiber, a tape-shaped reinforcing fiber bundle "toe" is wound around a bobbin, and the tape-shaped reinforcing fiber bundles drawn from the "tow" can be arranged to obtain a reinforcing fiber sheet. In addition, it has a reinforcing fiber arrangement mechanism for orderly arranging the reinforcing fiber bundles drawn from the bobbins hung on the creel and eliminating unwanted overlap and folding of the reinforcing fiber bundles in the reinforcing fiber sheet and gaps between the reinforcing fiber bundles. Is preferable. As the reinforcing fiber arranging mechanism, a known roller, comb-shaped arranging device, or the like can be used. It is also useful to stack a plurality of pre-arranged reinforcing fiber sheets from the viewpoint of reducing the gaps between the reinforcing fibers. It is preferable that the creel is provided with a tension control mechanism when pulling out the reinforcing fibers. As the tension control mechanism, a known one can be used, and examples thereof include a brake mechanism. The tension can also be controlled by adjusting the thread guide.

On the other hand, specific examples of the reinforcing fiber fabric include those in which reinforcing fibers are arranged in two dimensions in multiple axes, and those in which reinforcing fibers are randomly oriented such as non-woven fabric, matte, and paper, in addition to woven fabrics and knitted fabrics. .. In this case, the reinforcing fibers can also be made into a sheet by using a method such as binder addition, entanglement, welding, and fusion. As the woven fabric, in addition to the basic weave structure of plain weave, twill and satin, non-crimp woven fabric, bias structure, leno weave, multi-axis woven fabric, multiple woven fabric and the like can be used. A woven fabric that combines a bias structure and a UD base material not only suppresses deformation of the woven fabric due to pulling in the coating / impregnation process due to the UD structure, but also has pseudo-isotropic properties due to the bias structure, which is a preferable form. .. Further, the multi-woven fabric has an advantage that the upper surface or the lower surface of the woven fabric and the structure and characteristics inside the woven fabric can be designed respectively. For knitting, warp knitting is preferable in consideration of shape stability in the coating / impregnation step, but a blade which is a tubular knitting can also be used.

Among these, when giving priority to the mechanical properties of FRP, it is preferable to use a UD base material, and the UD base material can be produced by a known method of arranging reinforcing fibers in a sheet shape in one direction. ..

<Smoothing of reinforcing fiber sheet>
In the present invention, by increasing the surface smoothness of the reinforcing fiber sheet, the uniformity of the coating amount at the coating portion can be improved. Therefore, it is preferable to smooth the reinforcing fiber sheet and then lead it to the liquid pool portion. The smoothing treatment method is not particularly limited, and examples thereof include a method of physically pressing with an opposing roll and a method of moving the reinforcing fibers using an air flow. The method of physically pressing is preferable because it is simple and does not disturb the arrangement of the reinforcing fibers. More specifically, calendar processing or the like can be used. The method using airflow is preferable because not only scratching is less likely to occur, but also the effect of widening the reinforcing fiber sheet is obtained.

<Wide width of reinforcing fiber sheet>
Further, in the present invention, it is also preferable to widen the reinforcing fiber sheet and then guide it to the liquid pool portion from the viewpoint of efficiently producing a thin prepreg. The widening treatment method is not particularly limited, and examples thereof include a method of mechanically applying vibration and a method of expanding the reinforcing fiber bundle by an air flow. As a method of mechanically applying vibration, for example, as described in Japanese Patent Application Laid-Open No. 2015-22799, there is a method of bringing a reinforcing fiber sheet into contact with a vibrating roll. As for the vibration direction, when the traveling direction of the reinforcing fiber sheet is the X-axis, it is preferable to give vibration in the Y-axis direction (horizontal direction) and the Z-axis direction (vertical direction). It is also preferable to use them in combination. Further, it is preferable that the surface of the vibrating roll is provided with a plurality of protrusions because the scratching of the reinforcing fibers on the roll can be suppressed. As a method using airflow, for example, SEN-I
GAKKAISHI, vol. 64, P-262-267 (2008). The described method can be used.

<Preheating of reinforcing fiber sheet>
Further, in the present invention, when the reinforcing fiber sheet is heated and then guided to the liquid pool portion, it is preferable to perform preheating because the temperature drop of the matrix resin can be suppressed and the viscosity uniformity of the matrix resin can be improved. The reinforcing fiber sheet is preferably heated to near the matrix resin temperature, and various heating means for this purpose include air heating, infrared heating, far infrared heating, laser heating, contact heating, and heat medium heating (steam, etc.). Means can be used. Among them, infrared heating is preferable because the apparatus is simple and the reinforcing fiber sheet can be directly heated, so that it can be efficiently heated to a desired temperature even if the traveling speed is high.

<Matrix resin>
The matrix resin used in the present invention can be used as a resin composition containing various resins and particles described later, a curing agent, and various additives. The prepreg obtained by the present invention is in a state where the reinforcing fiber sheet is impregnated with the matrix resin, and can be laminated and molded as it is as a sheet-shaped prepreg to obtain a member made of FRP. The degree of impregnation can be controlled by designing the coating portion and additional impregnation after coating. The matrix resin can be appropriately selected depending on the intended use, but it is common to use a thermoplastic resin or a thermosetting resin. The matrix resin may be a molten resin that has been heated and melted, or a matrix resin at room temperature. Further, it may be a solution or a varnished product using a solvent.

As the matrix resin, those generally used for FRP such as a thermoplastic resin, a thermosetting resin, and a photocurable resin can be used. Further, these may be used as they are if they are liquid at room temperature, or if they are solid or viscous liquid at room temperature, they may be heated to reduce the viscosity, or they may be melted and used as a melt, or a solvent. It may be dissolved in a solution or varnished for use.

The thermoplastic resin is selected from carbon / carbon bond, amide bond, imide bond, ester bond, ether bond, carbonate bond, urethane bond, urea bond, thioether bond, sulfone bond, imidazole bond, and carbonyl bond in the main chain. A polymer having a bond can be used. Specifically, polyacrylate, polyolefin, polyamide (PA), aramid, polyester, polycarbonate (PC), polyphenylene sulfide (PPS), polybenzoimidazole (PBI), polyimide (PI), polyetherimide (PEI), polysulfone. (PSU), polyethersulfone (PES), polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), polyaryletherketone (PAEK), polyamideimide (PAI), etc. are exemplified. can. In fields where heat resistance is required, such as for aircraft applications, PPS, PES, PI, PEI, PSU, PEEK, PEKK, PEAK and the like are suitable. On the other hand, in industrial applications, automobile applications, and the like, polyolefins such as polypropylene (PP), PA, polyester, PPS, and the like are suitable in order to increase molding efficiency. These may be polymers, or oligomers or monomers for low viscosity and low temperature coating. Of course, these may be copolymerized depending on the purpose, or various types may be mixed and used as a polymer blend or a polymer alloy.

Examples of the thermosetting resin include epoxy resin, maleimide resin, polyimide resin, resin having an acetylene terminal, resin having a vinyl end, resin having an allyl end, resin having a nadic acid end, and resin having a cyanate ester end. Be done. These can generally be used in combination with a curing agent or a curing catalyst. It is also possible to mix and use these thermosetting resins as appropriate.

As a thermosetting resin suitable for the present invention, an epoxy resin is preferably used because it is excellent in heat resistance, chemical resistance, and mechanical properties. In particular, epoxy resins using amines, phenols, and compounds having a carbon-carbon double bond as precursors are preferable. Specifically, as an epoxy resin using amines as precursors, various isomers of tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, triglycidylaminocresol, and phenols are precursors. As the epoxy resin to be used as a body, a bisphenol A type epoxy resin, a bisphenol F type epoxy resin, a bisphenol S type epoxy resin, a phenol novolac type epoxy resin, a cresol novolac type epoxy resin, and a compound having a carbon / carbon double bond are used as precursors. Examples of the epoxy resin to be used include, but are not limited to, an alicyclic epoxy resin. Bromoylated epoxy resins obtained by brominating these epoxy resins are also used. Epoxy resins using aromatic amines as precursors, such as tetraglycidyldiaminodiphenylmethane, are most suitable for the present invention because they have good heat resistance and good adhesion to reinforcing fibers.

The thermosetting resin is preferably used in combination with a curing agent. For example, in the case of an epoxy resin, the curing agent can be any compound having an active group capable of reacting with the epoxy group. Preferably, a compound having an amino group, an acid anhydride group, or an azide group is suitable. Specifically, dicyandiamide, various isomers of diaminodiphenyl sulfone, and aminobenzoic acid esters are suitable. Specifically, dicyandiamide is preferably used because of its excellent prepreg storage stability. Further, various isomers of diaminodiphenyl sulfone are most suitable for the present invention because they give a cured product having good heat resistance. As aminobenzoic acid esters, trimethylene glycol di-p-aminobenzoate and neopentyl glycol di-p-aminobenzoate are preferably used, and although they are inferior in heat resistance to diaminodiphenyl sulfone, they have higher tensile strength. Because it is excellent, it is selected and used according to the application. Of course, it is also possible to use a curing catalyst if necessary. Further, in order to improve the pot life of the matrix resin, it is also possible to use a curing agent or a curing catalyst and a complexing agent capable of forming a complex in combination.

Further, in the present invention, it is also preferable to use a thermosetting resin mixed with a thermoplastic resin. A mixture of thermosetting resin and thermoplastic resin gives better results than when the thermosetting resin is used alone. This is because thermosetting resins are generally brittle and can be autoclaved at low pressure, whereas thermoplastic resins are generally tough but difficult to autoclave. This is because it is possible to balance the physical properties and the moldability by using a mixture of these in order to show the contradictory characteristics of being present. When mixed and used, it is preferable to contain more than 50% by mass of the thermosetting resin from the viewpoint of the mechanical properties of the FRP obtained by curing the prepreg.

<Inorganic particles, organic particles, polymer particles>
Further, in the present invention, inorganic particles and organic particles can be contained in a matrix resin or a resin film described later. The inorganic particles are not particularly limited, and for example, carbon-based particles, boron nitride particles, titanium dioxide particles, silicon dioxide particles, and the like can be preferably used in order to impart conductivity, heat transfer, thixotropic properties, and the like. The organic particles are not particularly limited, but it is particularly preferable to use polymer particles because the toughness, impact resistance, vibration damping property, etc. of the obtained FRP can be improved. At this time, when the glass transition temperature (Tg) or melting point (Tm) of the polymer particles is higher than the matrix resin temperature by 20 ° C. or more, the morphology of the polymer particles is easily maintained in the matrix resin, which is preferable. The Tg of the polymer particles can be measured under the following conditions using a temperature-modulated DSC. As the temperature-modulated DSC device, Q1000 manufactured by TA Instruments, etc. is suitable, and it can be used by calibrating with high-purity indium under a nitrogen atmosphere. The measurement conditions can be such that the heating rate is 2 ° C./min, the temperature modulation condition is a period of 60 seconds, and the amplitude is 1 ° C. The reversible component can be separated from the total heat flow obtained by this, and the temperature at the midpoint of the stepped signal can be set to Tg.

Further, Tm is measured by a normal DSC at a heating rate of 10 ° C./min, and the peak top temperature of the peak-like signal corresponding to melting can be set as Tm.

Further, the polymer particles are preferably insoluble in the matrix resin, and as such polymer particles, for example, those described in the WO2009 / 142231 pamphlet can be referred to, and appropriate ones can be used. More specifically, polyamide and polyimide can be preferably used, and polyamide is most preferable because it has excellent toughness and can greatly improve impact resistance. Examples of the polyamide include polyamide 12, polyamide 11, polyamide 6, polyamide 66 and polyamide 6/12 copolymer, and the epoxy compound described in Example 1 of JP-A No. 01-104624, which is a semi-IPN (polymer interpenetrating network structure). A modified polyamide (semi-IPN polyamide) or the like can be preferably used. The shape of the thermoplastic resin particles may be spherical particles, non-spherical particles, or porous particles, but the spherical shape is particularly preferable in the production method of the present invention because it does not deteriorate the flow characteristics of the resin. Further, if it is spherical, there is no starting point of stress concentration, and it is also a preferable embodiment in that it gives high impact resistance.

Commercially available products of polyamide particles include SP-500, SP-10, TR-1, TR-2, 842P-48, 842P-80 (all manufactured by Toray Co., Ltd.), "Organsol (registered trademark)" 1002D. , 2001UD, 2001EXD, 2002D, 3202D, 3501D, 3502D, (all manufactured by Alchema Co., Ltd.), "Grillamide (registered trademark)" TR90 (manufactured by Mzabelke Co., Ltd.), "TROGAMID (registered trademark)" CX7323, CX9701 , CX9704, (manufactured by Degusa Co., Ltd.) and the like can be used. These polyamide particles may be used alone or in combination of two or more.

Further, in order to increase the toughness of the reinforcing fiber interlayer resin layer of FRP, it is preferable to keep the polymer particles in the reinforcing fiber interlayer resin layer. Therefore, the number average particle size of the polymer particles is preferably in the range of 5 to 50 μm, more preferably in the range of 7 to 40 μm, and further preferably in the range of 10 to 30 μm. By setting the number average particle size to 5 μm or more, the particles do not penetrate into the bundle of reinforcing fibers and can stay in the reinforcing fiber interlayer resin layer of the obtained fiber-reinforced composite material. By setting the number average particle size to 50 μm or less, the thickness of the matrix resin layer on the surface of the prepreg can be optimized, and the fiber mass content in the obtained FRP can be optimized.

<Viscosity of matrix resin>
As the matrix resin used in the present invention, it is preferable to select an optimum viscosity from the viewpoint of process passability and stability. Specifically, when the viscosity is in the range of 1 to 60 Pa · s, it is possible to suppress dripping at the outlet of the narrowed portion and improve the high-speed running performance and stable running performance of the reinforcing fiber sheet, which is preferable. Here, the viscosity is measured at a strain rate of 3.14 s- ¹ and the matrix resin temperature at the liquid pool. As the measuring device, a viscoelasticity measuring device such as a parallel disk type or a cone type can be used. The viscosity of the matrix resin is more preferably 10 to 30 Pa · s.

<Matrix resin coating process>
Taking the UD base material as an example, the process of applying the matrix resin will be described with reference to FIG. 1a. After arranging the reinforcing fibers 1 of the above in one direction (paper surface depth direction) by the arranging device 12 to obtain the reinforcing fiber sheet 1a, the reinforcing fiber sheet 1a is passed through the coating portion 20 to form both surfaces of the reinforcing fiber sheet 1a. The matrix resin 2 is applied. Thereby, the primary prepreg 1c can be obtained. In the second production method of the present invention, the modifier is applied before the reinforcing fiber sheet 1a is introduced into the coating portion 20.

Next, with reference to FIGS. 2 to 4, the step of applying the matrix resin 2 to the reinforcing fiber sheet 1a or the reinforcing fiber sheet 1b to which the modifier is applied will be described in detail. Since this is a process common to the first manufacturing method and the second manufacturing method, the first manufacturing method will be described as an example. FIG. 2 is an enlarged detailed cross-sectional view of the coating portion 20 in FIG. 1a. The coating portion 20 includes wall surface members 21a and 21b facing each other with a predetermined gap D opened, and the cross-sectional area is continuous in the vertical downward direction Z (that is, the traveling direction of the reinforcing fiber sheet) between the wall surface members 21a and 21b. It is located below the liquid pool portion 22 (the carry-out side of the reinforcing fiber sheet 1a) and smaller than the cross-sectional area of the upper surface of the liquid pool portion 22 (the introduction side of the reinforcing fiber sheet 1a). A slit-shaped narrowed portion 23 having a cross-sectional area is formed. In FIG. 2, the reinforcing fiber sheets 1a are arranged in the depth direction of the paper surface.

In the coating portion 20, the reinforcing fiber sheet 1a introduced into the liquid pool portion 22 travels downward Z in the vertical direction, accompanied by the matrix resin 2 around the reinforcing fiber sheet 1a. At that time, since the cross-sectional area of the liquid pool portion 22 decreases in the vertical direction downward Z (the traveling direction of the reinforcing fiber sheet 1a), the accompanying matrix resin 2 is gradually compressed and heads toward the lower portion of the liquid pool portion 22. As the pressure of the matrix resin 2 increases. When the pressure at the lower part of the liquid pool portion 22 becomes higher, the accompanying liquid flow becomes more difficult to flow to the lower part and flows in the direction of the wall surface members 21a and 21b, and then is blocked by the wall surface members 21a and 21b and flows upward. Will be. As a result, the flat surface of the reinforcing fiber sheet 1a and the circulating flow T along the wall surfaces of the wall surface members 21a and 21b are formed in the liquid pool portion 22. As a result, even if the sheet-shaped reinforcing fiber 1a brings the fluff to the liquid pool portion 22, the fluff moves along the circulating flow T and cannot approach the lower portion of the liquid pool portion 22 or the narrowed portion 23 having a large liquid pressure. .. Further, as described below, the bubbles adhere to the fluff, so that the fluff moves upward from the circulating flow T and passes near the upper liquid level of the liquid pool portion 22. Therefore, not only is it possible to prevent the fluff from being clogged in the lower portion of the liquid pool portion 22 and the narrowed portion 23, but it is also possible to easily collect the retained fluff from the upper liquid surface of the liquid pool portion 22. Further, when the reinforcing fiber sheet 1a is run at a high speed, the hydraulic pressure is further increased, so that the effect of removing fluff is further enhanced. As a result, the reinforcing fiber sheet 1a can apply the matrix resin 2 at high speed, and the productivity is greatly improved.

Further, the increased hydraulic pressure has an effect that the matrix resin 2 is easily impregnated into the inside of the reinforcing fiber sheet 1a. This is based on the property that when a porous body such as a reinforcing fiber bundle is impregnated with a matrix resin, the degree of impregnation increases with the pressure of the matrix resin (Dalcy's law). Also in this case, when the reinforcing fiber sheet 1a is run at a higher speed, the hydraulic pressure is further increased, so that the impregnation effect can be further enhanced. The matrix resin 2 is impregnated with air bubbles remaining inside the reinforcing fiber sheet 1a by gas / liquid replacement, and the air bubbles pass through the gaps inside the reinforcing fiber sheet 1a due to the hydraulic pressure and buoyancy of the fibers. It is discharged in the orientation direction (vertical direction upward). At this time, since the bubbles are discharged without pushing away the impregnated matrix resin 2, there is also an effect that the impregnation is not hindered. In addition, some of the bubbles are discharged from the surface of the reinforcing fiber sheet 1a in the out-of-plane direction (normal direction), but these bubbles are also quickly eliminated upward in the vertical direction by the above-mentioned hydraulic pressure and buoyancy, so that they are impregnated. It does not stay at the lower part of the highly effective liquid pool portion 22, and has the effect of efficiently discharging air bubbles. Due to these effects, the reinforcing fiber sheet 1a can be efficiently impregnated with the matrix resin 2, and as a result, a high-quality primary prepreg 1c uniformly impregnated with the matrix resin 2 can be obtained.

Further, due to the increased hydraulic pressure, the reinforcing fiber sheet 1a is automatically centered in the center of the gap D, and the reinforcing fiber sheet 1a does not directly rub against the wall surface of the liquid pool portion 22 or the narrowed portion 23. It also has the effect of suppressing the development of fluff. This is because when the reinforcing fiber sheet 1a approaches either of the gaps D due to disturbance or the like, the matrix resin 2 is pushed into the narrower gap and compressed on the approaching side, so that the hydraulic pressure further increases on the approaching side. This is to push the reinforcing fiber sheet 1a back to the center of the gap D.

The narrowed portion 23 is designed to have a smaller cross-sectional area than the upper surface of the liquid pool portion 22. As can be understood from FIGS. 2 and 4, the length of the pseudo-plane by the reinforcing fiber sheet in the perpendicular direction is small, that is, the distance between the members is narrowed, so that the cross-sectional area is small. This is to obtain the impregnation and automatic alignment effect by increasing the hydraulic pressure at the narrowed portion as described above. Further, it is necessary to match the cross-sectional shape of the uppermost surface of the narrowed portion 23 with the cross-sectional shape of the lowermost surface of the liquid pool portion 22 from the viewpoint of the runnability of the reinforcing fiber sheet 1a and the flow control of the matrix resin 2. Although it is preferable, the narrowed portion 23 may be slightly larger if necessary.

Here, in the coating portion 20 of FIG. 2, the reinforcing fiber sheet 1a runs completely downward in the vertical direction (90 degrees from the horizontal plane), but the present invention is not limited to this, and the fluff recovery and air bubble discharge effects are not limited to this. The obtained reinforcing fiber sheet 1a may be substantially vertically downward within a range in which the reinforcing fiber sheet 1a can travel stably and continuously.

Further, the total amount of the matrix resin 2 applied to the reinforcing fiber sheet 1a can be controlled by the gap D of the narrowed portion 23. For example, it is desired to increase the total amount of the matrix resin 2 applied to the reinforcing fiber sheet 1a (with a large basis weight). If you want to do so, you may install the wall surface members 21a and 21b so that the gap D becomes wider.

FIG. 3 is a bottom view of the coating portion 20 as viewed from the direction A in FIG. The coating portion 20 is provided with side wall members 24a and 24b for preventing the matrix resin 2 from leaking from both ends in the arrangement direction of the reinforcing fiber sheet 1a, and is surrounded by the wall surface members 21a and 21b and the side wall members 24a and 24b. The outlet 25 of the narrowed portion 23 is formed in the space. Here, the outlet 25 has a slit shape, and the cross-sectional aspect ratio (Y / D in FIG. 3) may be set according to the shape of the reinforcing fiber sheet 1a to which the matrix resin 2 is to be applied.

FIG. 4a is a cross-sectional view illustrating the structure inside the coating portion when the coating portion 20 is viewed from the direction of B. The wall surface member 21b is omitted to make the figure easier to see, and the reinforcing fiber sheet 1a is drawn so that the reinforcing fibers 1 are arranged with a gap, but the reinforcing fibers 1 are actually drawn. It is preferable to arrange them without gaps from the viewpoint of the quality of the sheet-shaped prepreg and the mechanical properties of the FRP.

FIG. 4b shows the flow of the matrix resin 2 in the gap 26. When the gap 26 is large, a vortex flow is generated in the matrix resin 2 in the direction of R. Since this vortex flow R becomes an outward flow (Ra) at the lower part of the liquid pool portion 22, the reinforcing fiber sheet may be torn (cracking of the sheet-shaped fiber bundle occurs) or the interval between the reinforcing fibers may be increased. It spreads, and as a result, uneven arrangement of the reinforcing fibers may occur when the prepreg is used. On the other hand, in the upper part of the liquid pool portion 22, since the flow (Rb) is inward, the reinforcing fiber sheet 1a may be compressed in the width direction and the end portion thereof may be broken. In a device for double-sided coating of a matrix resin on an integral sheet-like base material (particularly a film) as represented by Patent Document 2 (Patent No. 3252278), such a vortex flow occurs in the gap 26. However, attention was not paid because it has little effect on quality.

Therefore, in the present invention, it is preferable to regulate the width to reduce the gap 26 and suppress the generation of vortex flow at the end portion. Specifically, the width L of the liquid pool portion 22, that is, the distance L between the side plate members 24a and 24b may be configured to satisfy the following relationship with the width W of the primary prepreg measured directly under the narrowed portion 23. preferable.
L ≦ W + 10 (mm)
As a result, the generation of vortex flow at the end can be suppressed, cracking and edge breakage of the reinforcing fiber sheet 1a can be suppressed, and the reinforcing fibers 1 are uniformly arranged over the entire width (W) of the primary prepreg 1c, resulting in high quality. It is possible to obtain a highly stable primary prepreg 1c. Further, when this technique is applied to a prepreg, not only the quality and quality of the prepreg can be improved, but also the mechanical properties and quality of the FRP obtained by using the prepreg can be improved. More preferably, when L ≦ W + 2 (mm), the relationship between L and W can further suppress cracking and edge breakage of the reinforcing fiber sheet.

Further, it is preferable to adjust the lower limit of L to be W-5 (mm) or more from the viewpoint of improving the uniformity of the width direction dimension of the primary prepreg 1c.

It is preferable that this width regulation is performed at least in the lower part of the liquid pool portion 22 (position G in FIG. 4a) from the viewpoint of suppressing the generation of the vortex flow R due to the high hydraulic pressure in the lower portion of the liquid pool portion 22. Further, more preferably, when this width regulation is performed over the entire area of the liquid pool portion 22, the generation of the vortex flow R can be suppressed almost completely, and as a result, cracks and edge breaks of the reinforcing fiber sheet are almost completely suppressed. Can be suppressed.

Further, the width regulation may be limited to the liquid pool portion 22 from the viewpoint of suppressing the vortex flow of the gap 26, but if the narrowing portion 23 is also performed in the same manner, the excess matrix resin 2 is imparted to the side surface of the primary prepreg 1c. It is preferable from the viewpoint of suppressing being carried out.

<Width regulation mechanism>
In the above, the case where the side wall members 24a and 24b are responsible for the width regulation is shown, but as shown in FIG. 5, the width regulation mechanisms 27a and 27b may be provided between the side wall members 24a and 24b, and the width regulation may be performed by such a mechanism. can. This is preferable from the viewpoint that prepregs having various widths can be manufactured by one coating portion by making it possible to freely change the width regulated by the width regulating mechanism. Here, the relationship between the width (W) of the reinforcing fiber sheet immediately below the narrowed portion and the width (L2) regulated by the width regulating mechanism at the lower end of the width regulating mechanism is preferably L2 ≦ W + 10 (mm). More preferably, L2 ≦ W + 2 (mm). Further, it is preferable to adjust the lower limit of L2 to be W-5 (mm) or more, preferably W (mm) or more, from the viewpoint of improving the uniformity of the widthwise dimension of the prepreg 1b. The shape and material of the width regulation mechanism are not particularly limited, but a plate-shaped bush is convenient and preferable. Further, at the upper part, that is, near the liquid surface, the width smaller than the distance between the wall surface members 21a and 21b (see FIG. 5. In the "view from the Z direction", the length in the vertical direction of the width regulating mechanism). By having it, it is possible not to obstruct the horizontal flow of the matrix resin, which is preferable. On the other hand, it is preferable that the shape from the middle portion to the lower portion of the width regulating mechanism conforms to the internal shape of the coating portion because the retention of the matrix resin in the liquid pool portion can be suppressed and the deterioration of the matrix resin can be suppressed. From this point of view, it is preferable that the width regulating mechanism is inserted up to the narrowed portion 23. FIG. 5 shows an example of a plate-shaped bush as a width regulating mechanism, and shows an example in which the lower part of the bush is inserted along the tapered shape of the liquid pool portion 22 to the narrowed portion 23. Although FIG. 5 shows a constant example of L2 from the liquid level to the outlet, the width regulated by the site may be changed within a range that achieves the purpose of the width regulating mechanism. The width regulation mechanism can be fixed to the coating portion 20 by any method, but in the case of a plate-shaped bush, by fixing it at a plurality of parts in the vertical direction, it is regulated by deformation of the plate-shaped bush due to high hydraulic pressure. Fluctuations in width can be suppressed. For example, if a stay is used for the upper part and the lower part is inserted into the coating portion, the width can be easily regulated by the width regulating mechanism, which is preferable.

<Shape of liquid pool>
As described in detail above, in the present invention, the liquid pressure can be increased in the traveling direction of the reinforcing fiber sheet by continuously reducing the cross-sectional area in the traveling direction of the reinforcing fiber sheet at the liquid pool portion 22. Although it is important, the fact that the cross-sectional area of the reinforcing fiber sheet continuously decreases in the traveling direction is not particularly limited as long as the hydraulic pressure can be continuously increased in the traveling direction. In the cross-sectional view of the liquid pool portion, a curved shape such as a tapered shape (straight line shape) or a trumpet shape may be shown. Further, the cross-sectional area reduction portion may be continuous over the entire length of the liquid pool portion, and as long as the object and effect of the present invention can be obtained, a portion in which the cross-sectional area does not decrease or a portion in which the cross-sectional area expands conversely is included. You may be. These will be described in detail below with reference to FIGS. 6 to 9.

FIG. 6 is a detailed cross-sectional view of the coating portion 20b of the embodiment different from that of FIG. It is the same as the coating portion 20 of FIG. 2 except that the shapes of the wall surface members 21c and 21d constituting the liquid pool portion 22 are different. As in the coating portion 20b of FIG. 6, the liquid pool portion 22 may be divided into a region 22a in which the cross-sectional area continuously decreases downward Z in the vertical direction and a region 22b in which the cross-sectional area does not decrease. At this time, the height H in the vertical direction in which the cross-sectional area continuously decreases is preferably 10 mm or more. The height H in the vertical direction, in which the preferable cross-sectional area continuously decreases, is 50 mm or more. As a result, the distance that the matrix resin 2 accompanied by the reinforcing fiber sheet 1a is compressed in the region 22a where the cross-sectional area of the liquid pool portion 22 continuously decreases is secured, and the liquid generated in the lower part of the liquid pool portion 22 is secured. The pressure can be increased sufficiently. As a result, it is possible to prevent the fluff from being clogged in the narrowed portion 23 by the hydraulic pressure, and to obtain the effect of impregnating the reinforcing fiber sheet 1a with the matrix resin 2 by the hydraulic pressure. When the reinforcing fiber sheet is passed in the horizontal direction or the inclined direction in the coated portion, "vertical direction" should be read as "horizontal direction" or "inclined direction", and "height" should be read as "liquid pool portion". It shall be read as "distance from the outlet (that is, the interface between the liquid pool and the constriction)".

Here, when the region 22a in which the cross-sectional area of the liquid pool portion 22 continuously decreases is tapered as in the coating portion 20 of FIG. 2 and the coating portion 20b of FIG. 6, the opening angle θ of the taper is smaller. Is preferable, and specifically, an acute angle (90 ° or less) is preferable. As a result, the compression effect of the matrix resin 2 can be enhanced in the region 22a (tapered portion) where the cross-sectional area of the liquid pool portion 22 continuously decreases, and a high liquid pressure can be easily obtained.

FIG. 7 is a detailed cross-sectional view of the coating portion 20c of the embodiment different from that of FIG. It is the same as the coating portion 20b in FIG. 6 except that the wall surface members 21e and 21f constituting the liquid pool portion 22 have a two-step taper shape. In this way, the region 22a in which the cross-sectional area of the liquid pool portion 22 continuously decreases may be composed of two or more stages of multi-stage tapered portions. At this time, it is preferable to make the opening angle θ of the tapered portion closest to the narrowed portion 23 an acute angle from the viewpoint of enhancing the compression effect. Also in this case, it is preferable that the height H of the region 22a where the cross-sectional area of the liquid pool portion 22 continuously decreases is 10 mm or more. The height H in the vertical direction, in which the preferable cross-sectional area continuously decreases, is 50 mm or more. By forming the region 22a in which the cross-sectional area of the liquid pool portion 22 continuously decreases as shown in FIG. 7 into a multi-stage tapered portion, the constricted portion 23 maintains the volume of the matrix resin 2 that can be stored in the liquid pool portion 22. The angle θ of the tapered portion closest to can be made smaller. As a result, the hydraulic pressure generated in the lower part of the liquid pool portion 22 becomes higher, and the effect of removing fluff and the effect of impregnating the matrix resin 2 can be further enhanced.

FIG. 8 is a detailed cross-sectional view of the coating portion 20d of the embodiment different from that of FIG. It is the same as the coating portion 20b in FIG. 6 except that the wall surface members 21g and 21h constituting the liquid pool portion 22 have a stepped shape. As described above, if there is a region 22a at the lowermost portion of the liquid pool portion 22 where the cross-sectional area continuously decreases, the effect of increasing the hydraulic pressure, which is the object of the present invention, can be obtained. May include a region 22c in which the cross-sectional area decreases intermittently. By forming the liquid pool portion 22 into the shape as shown in FIG. 8, the matrix resin 2 capable of expanding and storing the depth B of the liquid pool portion 22 while maintaining the shape of the region 22a in which the cross-sectional area continuously decreases. The volume can be increased. As a result, even when the matrix resin 2 cannot be continuously supplied to the coated portion 20d, the matrix resin 2 can be continuously applied to the reinforcing fiber sheet 1a for a long time, and the productivity of the prepreg is further improved.

FIG. 9 is a detailed cross-sectional view of the coating portion 20e of the embodiment different from that of FIG. It is the same as the coating portion 20b in FIG. 6 except that the wall surface members 21i and 21j constituting the liquid pool portion 22 have a trumpet shape (curved shape). In the coating portion 20b of FIG. 6, the region 22a in which the cross-sectional area of the liquid pool portion 22 continuously decreases is tapered (straight), but is not limited to this, and is not limited to this, for example, a trumpet (curve) as shown in FIG. But it may be. However, it is preferable that the lower portion of the liquid pool portion 22 and the upper portion of the narrowed portion 23 are smoothly connected. This is because if there is a step at the boundary between the lower part of the liquid pool portion 22 and the upper part of the narrowed portion 23, the reinforcing fiber sheet 1a may be caught in the step and fluff may be generated at this portion. Further, when the region where the cross-sectional area of the liquid pool portion 22 continuously decreases is formed into a trumpet shape, the opening of the virtual tangent line at the lowermost portion of the region 22a where the cross-sectional area of the liquid pool portion 22 continuously decreases. It is preferable that the angle θ is an acute angle.

Although the above description has given an example in which the cross-sectional area is smoothly reduced, the cross-sectional area of the liquid pool portion does not necessarily have to be smoothly reduced in the present invention as long as the object of the present invention is not impaired.

FIG. 10 is a detailed cross-sectional view of the coating portion 30 of the embodiment different from the present invention. Unlike the embodiment of the present invention, the liquid pool portion 32 of FIG. 10 does not include a region in which the cross-sectional area continuously decreases in the vertical direction Z downward, and the cross-sectional area is discontinuous and abrupt at the boundary 33 with the constricted portion 23. It is a configuration that decreases to. Therefore, the reinforcing fiber sheet 1a is easily clogged.

It is also possible to improve the impregnation effect by bringing the reinforcing fiber sheet into contact with a plurality of bars in the coated portion. FIG. 11 shows an example in which three bars (35a, 35b and 35c) are used. The larger the number of bars, the longer the contact length between the reinforcing fiber sheet and the bar, and the larger the contact angle, the more the impregnation rate. Can be improved. In the example of FIG. 11, the impregnation rate can be 90% or more. A plurality of types of means for improving the impregnation effect may be used in combination.

<Spray application process>
Next, the step of spray coating after the formation of the primary prepreg used in the first production method will be described in detail. In the second manufacturing method, spray coating can be used as a means for applying the modifier, but in this case, the coating is applied on the reinforcing fiber sheet. The spray coating step referred to in the present invention is a step of discharging a liquid from a discharge portion, guiding the discharged liquid by an air flow or an electric line of force, and collecting the discharged liquid on a continuously conveyed sheet. Say that. Examples of the method using airflow include melt blow and spunbond. These methods are described, for example, in "Latest Spinning Technology", edited by the Textile Society, Polymer Publishing Society, p123 to p127 (melt blow method), p118 to 123 (spanbond method), (1992). .. In this coating method, the apparatus is relatively simple. Further, as a method using electric lines of force, an electrospinning method and an electrospray method can be mentioned. These methods are described, for example, in "Nanofiber Technology", CMC Publishing, pp. 113-118. In this coating method, since the coating direction is determined by the lines of electric force, coating can be performed not only from top to bottom but also from bottom to top and horizontal, and the coating surface can be selected and the primary prepreg transport direction (from top). There is a degree of freedom in setting (bottom, horizontal, bottom to top, etc.).

If the liquid to be discharged is a solid at room temperature, it can be melted by heating or dissolved in a solvent to be liquefied. Further, even if it is a liquid at room temperature, it can be diluted by adding a solvent. Further, the liquid may contain solid substances such as the above-mentioned inorganic particles, organic particles and polymer particles.

Hereinafter, the spray coating method using an air flow will be described in detail.

In this spray coating method, it is preferable that the mouthpiece holes are arranged in one to several rows in the width direction and a heated air flow is applied in the vicinity of the portion where the liquid is discharged, as in the melt blow method. At this time, as shown in FIG. 12, it is preferable to apply the airflow 44 from the front and back of the base hole rows arranged in the width direction from the viewpoint of coating stability. Further, by adjusting the temperature, flow rate, flow velocity, and direction of the air flow, it is possible to control the spinnability and cooling of the discharged liquid and its solidified product 46. The melt blow method is usually used for producing a short fiber non-woven fabric of a thermoplastic resin, and a high-speed airflow is applied to a low-viscosity resin to blow off the resin discharged from the mouthpiece holes to shorten the fibers. The fiber diameter of the resin fiber obtained here varies widely from 1 μm to several tens of μm. In the present invention, from the viewpoint of improving the basis weight uniformity of the resin, it is preferable to reduce the variation in fiber diameter as much as possible, and to make continuous fibers, that is, long fibers, instead of short fibers. The manufacturing conditions of the melt blow method used in ordinary polyester non-woven fabrics are set so that the resin viscosity is ultra-low viscosity and the air flow velocity associated with the discharged polymer is also high in order to obtain ultrafine fibers. However, in the present invention, the discharge conditions, the accompanying air flow velocity, and the like are adjusted for the purpose of uniformly applying the liquid and the solidified product 46 thereof on the primary prepreg 1b. From this point of view, the viscosity of the liquid in the spray coating apparatus is preferably 1 to 60 Pa · s. For the viscosity of the liquid, the value measured at a ^{strain rate of 3.14 sec -1 can be used.} On the other hand, the air flow velocity can be determined while observing the fibrous state of the discharged liquid 19.

Whether the discharged liquid or its solidified product 46 is formed into a fibrous form is determined by, for example, the path of the fibrous formed liquid or its solidified material 46 reaching the primary prepreg 1c from the spray coating device 41. The movement of (spinning wire) can be judged by shooting it with a high-speed video camera and observing it. In the case of continuous fibrous formation, the movement of the fibrous shaped liquid and its solidified product 46 is observed to be linked and swaying upstream and downstream of the spinning line. Further, when the solidified liquid collected on the primary prepreg 1c is observed, if it is in the form of a long-fiber non-woven fabric, it can be determined that the fibers are continuous fibers. Further, even in the case of short fibers, the solidified liquid collected on the primary prepreg 1c is observed, and it can be determined that the fibers are in the form of a short fiber non-woven fabric. In the present invention, the fiber length of the collected fibrous solidified liquid is preferably 1 cm or more, more preferably 10 cm or more, and further preferably continuous fibrousization. On the other hand, as described above, when the liquid is not made into continuous fibers and is scattered as droplets, the liquid collected on the primary prepreg 1c and its solidified material have a droplet shape. Further, even when observed with the above-mentioned high-speed video camera, it is difficult to observe that the spinning wire is linked and moving upstream and downstream.

In the present invention, when the discharged liquid and its solidified material are shaped into fibers and collected on the primary prepreg, unevenness in the basis weight of the liquid and its solidified material can be suppressed, and the quality of the prepreg can be improved. preferable. In addition, there is an advantage that the surroundings of the device can be less likely to be polluted by a liquid or a solidified product thereof. When the discharged liquid or its solidified material becomes droplets, especially in the case of minute droplets having a droplet size of several μm to several hundred μm, the droplet mass is small, so that the droplets are easily scattered and continuous fibers. Unlike the case of the above case, since there is no mechanism for retaining the scattering of the droplets, it is considered that dirt is likely to occur.

In the present invention, when the liquid is heated, the liquid is discharged and then cooled toward the primary prepreg, and the viscosity and rigidity increase. Especially in the case of continuous fibrous formation, when the viscosity and rigidity increase due to cooling, the path until the fibrous shaped liquid and its solidified material reach the primary prepreg is greatly affected by the air flow. become. In FIG. 13, when the height h (corresponding to the spinning length, hereinafter referred to as the coating height) from the primary prepreg 1b to the lower surface (base) of the spray coating device 41 which is the liquid discharging portion is low, it is fibrously applied. The formed liquid and its solidified material 46 reach the primary prepreg 1c in a state of low viscosity and low rigidity, and the arrival path (corresponding to a spinning wire) of the liquid formed into fibers by an air flow and its solidified material 46. Is not easily affected, so the fibrous shaped liquid and its solidified product 46 are less likely to cross or entangle in the middle of the spinning line or to flow horizontally on the primary prepreg 1c, and the spinning line. Becomes linear. Therefore, the intervals between the fibrous shaped liquid and the solidified 46 thereof are substantially equal, and the basis weight uniformity of the liquid and the solidified product 46 in the width direction is improved. On the other hand, when the coating height h is high as shown in FIG. 14, the liquid formed into fibers and the solidified product 46 thereof become highly viscous and highly rigid before reaching the primary prepreg 1c, so that the air flow causes the liquid to become highly viscous and highly rigid. The liquid may be easily flown, and the fibrous liquid or its solidified product 46 may be crossed or entangled in the middle of the spinning wire, or may be easily flowed in the horizontal direction on the primary prepreg 1c. Therefore, when the coating height h is set to 1 to 100 mm, the uniformity of the resin texture is improved, which is preferable. More preferably, it is 70 mm or less. On the other hand, when the coating height h is 25 mm or more, the turbulence of the air flow on the primary prepreg 1b is suppressed, so that the scattering of droplets and fibers of the liquid or its solidified material 46 is suppressed, and the vicinity of the coating process is suppressed. It is more preferable because it can suppress resin stains.

Further, when the discharged liquid is made into fibers, particularly continuous fibers, scattering due to the air flow can be suppressed, and the liquid in the vicinity of the coating process and solidified stains thereof can be suppressed, which is preferable.

Further, the fibrous shaped liquid and its solidified product discharged as described above are less likely to be affected by the air flow if they can maintain low viscosity and / or low rigidity even downstream of the spinning line. Therefore, it may be possible to control the cooling rate of the fibrous shaped liquid or its solidified material by the mass of the liquid or its solidified material or the specific surface area of the fiber, and to make it less susceptible to the influence of the air flow. Therefore, the single-hole discharge amount and the single-hole discharge area of the liquid can be adjusted. Further, even if the viscosity is lowered by using a low-viscosity liquid or raising the temperature of the discharged liquid, it may be difficult to be affected by the air flow. Since there is a limit to the upper limit of the resin temperature that can be applied to a thermosetting resin as a liquid, it is also effective to adjust the single-hole discharge amount and the single-hole discharge area as described above when the resin viscosity is high. Further, since the cooling and thinning process of the fibrous resin can be adjusted by the temperature, flow rate, and flow velocity of the air flow acting on the discharged resin, these process parameters can be appropriately combined. In industrial production equipment, the flow velocity and flow rate of the air flow may be adjusted by the pressure of the supplied air.

Further, in the present invention, when the discharged liquid or the solidified product thereof is collected in the region where the primary prepreg is substantially conveyed in a plane, the reinforcing fiber sheet is curved downward as described in Patent Document 5. It is possible to solve various problems caused by the above. Here, as shown in FIG. 12, the region in which the primary prepreg is substantially transported in a plane is a region in which the primary prepreg 1c is substantially straight in the longitudinal direction in the vicinity of the collecting portion of the liquid or its solidified product 46. The area that is being conveyed in a shape. This is because in FIG. 12, the primary prepreg 1c transported in the horizontal arrangement direction of the reinforcing fibers, that is, when viewed from the front to the back, near the collecting portion of the liquid or its solidified material 46 looks substantially linear. It means that. In the present invention, there is no particular limitation on a specific method for preventing the primary prepreg from bending downward even if there is a downward air flow in the spray coating step, but as shown in FIG. 12, for example, coating is performed. In the process, it is effective to dispose an object capable of supporting the primary prepreg 1c below the primary prepreg 1c (table 45 is illustrated in FIG. 12). Further, it is preferable to apply an appropriate tension to the primary prepreg to carry it, from the viewpoint of maintaining the arrangement of the reinforcing fibers.

<Curtain coating process>
Next, the curtain coating process after forming the primary prepreg will be described in detail. Here, curtain coating means that a liquid is discharged in a planar manner, a film-like substance is formed in the discharged space, and the film is applied, and the film is semi-solidified or solidified even if it is a liquid. Is also good. Therefore, since the coating is non-contact in the present invention, various problems caused by rubbing can be solved as compared with the method of pressing the coating head. In the second manufacturing method, curtain coating can be used as a means for applying the modifier, but in this case, the coating is applied on the reinforcing fiber sheet.

Next, in the present invention, it is preferable that the angle formed by the discharge direction of the liquid and the transport direction of the primary prepreg (this angle is sometimes referred to as a “coating angle” for convenience) is 80 ° or less. FIG. 15 shows a general coating method when the transport direction of the primary prepreg 1c is the horizontal direction, but the angle formed by the liquid discharge direction and the transport direction of the primary prepreg 1c is 90 °. .. When the present inventors conducted an experiment using a thermosetting resin (epoxy resin, etc.), the transfer speed was increased when the angle between the discharge direction of the liquid and the transfer direction of the primary prepreg was 90 °. Sometimes it was difficult to do. When the coating device is pressed against the primary prepreg, it is considered that such a problem does not occur because the film is not formed in the air. However, as shown in FIG. 16, by setting the angle between the liquid discharge direction and the transport direction of the primary prepreg 1c to 80 ° or less, the liquid is discharged in a planar manner to form the film 47. However, the present inventors have found that the coating can be applied stably and at high speed. The smaller the coating angle α, the more stable and high-speed coating can be performed, which is preferable. However, when the coating angle α becomes small, the size of the coating head tends to interfere with the transfer process of the primary prepreg, which may cause restrictions on the device. From this viewpoint, the coating angle α is preferably 30 to 70 °.

By setting the coating height h, which is the distance between the center of the discharge line and the primary prepreg 1c, as shown in FIG. It is preferable because it can improve the properties. Further, it is preferable that the thickness is 18 mm or less because the formation of the film is stabilized.

The curtain coating device may be any device capable of discharging liquid in a planar manner. More specifically, as a preferred example, a device capable of forming a surface or curtain-like film by discharging a liquid having a uniform thickness in the width direction from a base for discharging the liquid. Generally, what is called a die coater can be used, and a structure capable of discharging a liquid from a slit having a uniform thickness and without interruption can be used. Further, it is preferable that the curtain coating device has a heating mechanism capable of heating the liquid immediately before discharging and adjusting the viscosity to an arbitrary value. In particular, when a curable resin is used as a liquid, there is a risk of deterioration, viscosity increase, and runaway reaction due to the thermal history of the resin during storage. Therefore, shorten the heating time of the resin and perform appropriate temperature control. Is preferable. The viscosity of the liquid in the curtain coating device is preferably 1 to 60 Pa · s. For the viscosity of the liquid, the value measured at a ^{strain rate of 3.14 sec -1 can be used.}

Further, in the present invention, since the film has a free surface in the space where the liquid is discharged, the film shape is easily deformed. For example, the film formation becomes unstable because the edge of the film shrinks in the width direction due to so-called "neck-in", or the entire film is pulled when the primary prepreg is conveyed at high speed. Or, the uniformity of the texture of the film may be impaired. For this reason, it is preferable that the air flow acts on the end portion of the film in the width direction to stabilize the film formation.

In the membrane, a phenomenon called "neck-in" occurs in which the edge of the membrane is pulled toward the center of the membrane in the direction perpendicular to the pulling direction and the width of the membrane is reduced (see FIG. 17, the portion shown by N). , The width of the film 47 is reduced). It is considered that this phenomenon is particularly likely to occur when a high tension is applied to the film, such as when the viscosity of the liquid forming the film or its solidified product is high, or when the tensile speed is high. In particular, when the film is formed at high speed by the method for producing a prepreg of the present invention, it is preferable to suppress neck-in. Therefore, in the present invention, an air flow (end air 48) may be applied from the front surface of the membrane toward the end portion to, for example, blow (see FIGS. 17 and 18) to expand the end portion of the membrane. preferable. The airflow for this purpose is referred to as end air in the present invention. Generally, a metal tube or a nozzle can be used as a means for applying the end air. It is preferable to appropriately select the airflow velocity, flow rate, angle, position, and temperature of the end air in consideration of whether neck-in and resin film formation are stable. Further, the end air can be used when applying the film. When applying, before starting to discharge the liquid from the mouthpiece, when starting to discharge the liquid from the mouthpiece, while discharging the liquid from the mouthpiece, while the film is formed and the film is applied to the primary prepreg, etc. Can be selected and applied.

Further, as shown in FIG. 19, the film may be excessively pulled in the pulling direction of the film, that is, in the prepreg transport direction. At this time, for example, as shown in FIG. 20, the entire surface or almost the entire surface of the film 47 is seen. It is preferable to blow an air flow (surface air 47) toward the surface so that the position where the film 47 comes into contact with the primary prepreg 1c is closer to the curtain coating device side. The airflow for this purpose is referred to as surface air in the present invention. It is preferable that the air flow velocity, flow rate, angle, position, and temperature of the surface air are appropriately selected in consideration of whether or not the film is stably formed. As a means for applying surface air, a nozzle in which perforations are generally arranged in a slit shape or on a line can be used. Further, it is preferable that both the end air and the surface air are provided in the curtain coating device from the viewpoint of making the device compact and easy to handle (see FIG. 21). Further, regarding the action on the surface portion of the film, the position where the film contacts the primary prepreg can be brought closer to the coating portion side by sucking air from the back surface side of the film.

The above shows the case where the primary prepreg is horizontally conveyed, but as shown in FIG. 22, the curtain coating can also be applied to the primary prepreg on the roll. At this time, the angle formed by the tangent line and the discharge direction when the film 47 and the primary prepreg 1b on the roll 50 are in contact with each other can be defined as the “coating angle”.

<Liquid applied by spray coating or curtain coating in the first manufacturing method>
In the first production method of the present invention, the liquid to be applied to the primary prepreg by spray coating or curtain coating is not particularly limited and may be appropriately selected according to the intended purpose. For example, the above-mentioned matrix resin can be used. Further, a thermosetting resin or a thermoplastic resin can be used alone, or a curing agent or various additives can be used alone. Further, the liquid may contain solid substances such as the above-mentioned inorganic particles, organic particles, and polymer particles. Further, these viscosities can be adjusted to an appropriate viscosity for spray coating or curtain coating by adding heating or a solvent according to the purpose.

For example, when it is desired to impart tackiness to the surface of the prepreg, a substance capable of imparting tackiness such as a liquid epoxy resin, urethane resin, or rubber can be appropriately adjusted and used so as to have a desired tackiness. It is also possible to extract a part or all of the curing agent from the matrix resin used when forming the primary prepreg, and apply it again by spray coating or curtain coating. By doing so, the viscosity of the matrix resin used when forming the primary prepreg can be reduced, the process stability can be improved, and the production speed can be increased. It is also possible to extract a part or all of the particles from the matrix resin used when forming the primary prepreg, and apply the particles again by spray coating or curtain coating. By doing so, the viscosity of the matrix resin used when forming the primary prepreg can be reduced, the process stability can be improved, and the production speed can be increased. At this time, the particles can be used by forming a suspension with an appropriate liquid or by containing them in a thermosetting resin or a thermoplastic resin. Further, by doing so, the particles can be selectively arranged on the surface of the prepreg, and the particles can be selectively arranged between the reinforcing fiber layer and the reinforcing fiber layer. Further, by using a liquid that becomes solid at room temperature, it is possible to adjust the unevenness (roughness) of the prepreg surface, which can improve the vacuum pressure moldability and the like.

<Addition of modifier in the second manufacturing method>
In the second production method of the present invention, a modifier is applied to the reinforcing fiber sheet 1a before being introduced into the coated portion.

(Modifier)
The modifier is a general term for agents selected from the group consisting of a thread breakage inhibitor, a toughness improver, a flame retardant and a fluff sizing agent, and is an agent capable of improving the quality and functionality of a prepreg. .. As the modifier to be given, one modifier may be selected from these groups and given, and it is of course possible to use a plurality of modifiers in combination or to use them in combination. Each modifier will be described in detail.

(Thread breakage preventive agent)
The thread breakage inhibitor is an agent that enhances the basis weight uniformity in the width direction, which is an important grade of the prepreg. Thread cracking will be described with reference to FIG. 1b. When the carbon fiber is used as the reinforcing fiber 1, the reinforcing fiber sheet 1a can be obtained by arranging the toes, but while the reinforcing fiber sheet 1a is transported from the arranging device 12 to the coating portion 20, it is connected to the adjacent toes. The gap between the toes may crack. This is called thread cracking. When this thread-broken reinforcing fiber sheet is passed through the matrix resin 2, the obtained prepreg 1c may have poor quality without reinforcing fibers in the width direction, and the texture uniformity in the width direction may decrease. In particular, when the width of the portion without the reinforcing fibers in the width direction with respect to the reinforcing fiber arrangement direction of the prepreg 1c is 2 mm or more, it is determined that the quality is poor. This thread cracking can be improved or eliminated by applying a thread cracking inhibitor to the reinforcing fiber sheet 1a before passing through the coating portion 20. The anti-thread breakage agent is an agent that is applied so as to connect or hang between the tow. By restraining or suppressing the movement of the toe in the width direction by applying the thread breakage inhibitor, the reinforcing fiber sheet can be substantially integrated, and as a result, the thread breakage between the toe and the toe can be suppressed. .. The component of the thread cracking inhibitor to be imparted is not particularly limited as long as it can suppress thread cracking between the tow. When the thread cracking inhibitor is a combination of the matrix resin 2 to be applied in the coating portion 20 to be described later, the components contained in the matrix resin 2, or those selected from the components, the finally obtained prepreg is laminated and cured. It is preferable that the mechanical properties of the CFRP are not significantly reduced. As a specific component, a mixture selected and mixed from an epoxy resin, an epoxy resin curing agent, and a thermoplastic resin is also preferable, and the obtained prepreg is laminated and cured to improve the heat resistance, chemical resistance, and mechanical properties of CFRP. Excellent. As a specific example of the component of the thread cracking inhibitor to be applied, a low-viscosity resin is preferable, heating required for melting at the time of application can be omitted or simplified, and the degree of impregnation at the time of coating or additional impregnation is increased. Can be done. The low viscosity referred to here means a viscosity of 4000 Pa · s or less when measured at a ^{strain rate of 3.14 s -1 at 40 ° C.} As the measuring device, a viscoelasticity measuring device such as a parallel disk type or a cone type can be used.

(Toughness improver)
The toughness improver is an agent capable of increasing the toughness and impact resistance of CFRP obtained by laminating and hardening prepregs obtained by applying the prepreg. By applying the toughness improving agent to the reinforcing fiber sheet before entering the matrix resin, the toughness improving component can be given to the surface layer of the reinforcing fiber sheet, the toughness of CFRP can be enhanced, and further, as a thread cracking preventive agent. It is also possible to achieve the roles at the same time. Polyamide and polyimide are preferable as the components of the toughness improver to be imparted, and the impact resistance can be enhanced due to the excellent toughness. Further, from the viewpoint of imparting high heat resistance, Tg is preferably 180 ° C. or higher, and preferably has an aromatic ring in the molecule. Specifically, polyethersulfone, polyetherethersulfone, polyetherimide, polyphenylene oxide, polysulfone and the like are preferably used. As the toughness improver, these components can be melted and applied, or particles can be kneaded into a resin and used.

(Flame-retardant material)
The flame retardant is a chemical that can improve the flame retardancy of CFRP by adding it, and is a characteristic required particularly for structural members and building materials of aircraft and vehicles. By applying the flame retardant to the reinforcing fiber sheet before entering the matrix resin, the flame retardant of CFRP can be imparted by applying the flame retardant to the surface layer of the reinforcing fiber sheet. As the flame retardant used in the present invention, a resin kneaded with a generally known flame retardant can be used. For example, a resin obtained by kneading a phosphorus atom-containing compound such as a metal hydroxide, a metal oxide, a red phosphorus, a phosphoric acid ester, or a phosphate, a nitrogen-containing compound, or antimony trioxide can be used.

(Fluff focusing agent)
The fluff sizing agent is an agent that integrates the fluff that protrudes in the out-of-plane direction of the reinforcing fiber sheet into the reinforcing fiber sheet by applying it. If there is fluff protruding out of the plane of the reinforcing fiber sheet, the fluff may break when passing through the narrowed portion of the coated portion and may be deposited in the matrix resin stored in the coated portion. By applying a fluff sizing agent to the reinforcing fiber sheet before entering the coating portion in advance, the fluff protruding from the reinforcing fiber sheet in the coating portion is cut at the narrowed portion, and the fluff stays in the matrix resin stored in the coating portion. It is possible to suppress this, and it is also possible to simultaneously achieve the role as a thread breakage preventive agent. The component of the fluff sizing agent to be imparted is not particularly limited, but the fluff inhibitor is a combination of the matrix resin 2 to be applied in the coating portion 20 to be described later, the components contained in the matrix resin 2, or those selected from the components. At this time, it is preferable that the mechanical properties of the CFRP obtained by laminating and curing the finally obtained prepreg are not significantly deteriorated and the generation of fluff accumulated on the coated portion can be suppressed. As a specific component, a mixture selected and mixed from an epoxy resin, an epoxy resin curing agent, and a thermoplastic resin is also preferable, and the obtained prepreg is laminated and cured to improve the heat resistance, chemical resistance, and mechanical properties of CFRP. Excellent. As a specific example of the component of the fluff sizing agent to be applied, a low-viscosity resin is preferable, heating required for melting at the time of application can be omitted or simplified, and the degree of impregnation at the time of application or additional impregnation can be increased. can. The low viscosity referred to here means a viscosity of 4000 Pa · s or less when measured at a ^{strain rate of 3.14 s -1 at 40 ° C.} As the measuring device, a viscoelasticity measuring device such as a parallel disk type or a cone type can be used.

(Method of applying modifier)
The method for applying the modifier is not particularly limited, and various methods can be used, but the continuous productivity is lowered due to fluffing caused by rubbing with the reinforcing fiber sheet, and the arrangement and straightness of the reinforcing fibers are disturbed. A non-contact coating method for the reinforcing fiber sheet is preferable because it can be suppressed. For example, the spray coating (including melt blow) and curtain coating described above can be used.

(Metsuke of modifier to be given)
The combined basis weight of the modifier to be applied (mass of the modifier per unit area applied to the reinforcing fiber sheet 1a) is ^{preferably 20 g / m 2} or less. Within this range, process stability, quality, quality, and functionality of the prepreg can be obtained, and a large decrease in mechanical properties of the CFRP obtained by laminating and curing the finally obtained prepreg can be suppressed.

(Applying interval of modifier in the longitudinal direction)
When the width of the spray coating head is narrower than the width in the width direction of the reinforcing fiber sheet, the spray coating head can be traversed in the width direction. In this case, since the spray coating may have a zigzag shape on the reinforcing fiber sheet, the modifier may be intermittently applied to the traveling direction of the reinforcing fiber sheet. At this time, the application interval of the modifier in the longitudinal direction (also referred to as the spray application interval when the modifier is applied by spray coating) is preferably within 30 mm at the maximum, and when it is within this range, the effect of the modifier Easy to get. The maximum application interval is 30 mm or less when the reinforcing sheet to which the modifier is applied is observed at three locations near both ends and the center of the reinforcing fiber sheet at 100 cm (traveling direction) x 10 cm (width direction). In any of the observation points, it means that there is no part where the part to which the modifier is not applied is open at a distance exceeding 30 mm in the traveling direction. By using a wide spray coating head or by using a plurality of spray coating heads, the spray coating interval can be reduced even if the traveling speed of the reinforcing fiber sheet is increased.

<Step of applying modifier in the second manufacturing method>
The case where the UD base material is used as the reinforcing fiber sheet will be described with reference to FIG. 1b. The plurality of reinforcing fibers 1 unwound from the creel 11 are arranged by the arranging device 12, and the obtained reinforcing fiber sheet is linearly passed through the modifier applying device to apply the modifier, and the obtained reforming is performed. This is an example in which the reinforcing fiber sheet 1b to which the agent is applied is passed through the coating portion 20 by changing the traveling direction from the horizontal direction to the vertical downward direction by the transport roll 13.

As the modifier applying device, it can be appropriately selected and used from various applying devices without limitation within the range of achieving the object of the present invention. Spray coating (including melt blow) is preferable because it facilitates low basis weight coating. Further, since the melt blow guides the modifier to the reinforcing fiber sheet by the air flow, the contamination around the apparatus is small, the loss of the modifier is small, and the basis weight uniformity is high, which is preferable. The curtain cloth is preferable because the modifier can be applied without interruption.

The surface to which the modifier is applied may be one side or both sides with respect to the reinforcing fiber sheet 1a. In addition, in FIG. 1b, the place where the modifier is applied to the reinforcing fiber sheet 1a is the place where the modifier is applied in the section for horizontally transporting the reinforcing fiber sheet 1a obtained by the arranging device 12 to the transport roll 13 for changing the direction. An example in which the apparatus 28 is provided and the modifier is applied is shown, but of course, the addition of the modifier is not particularly limited as long as it is between the reinforcing fiber arranging device 12 and the coating portion 20, and the modifier is applied from the transport roll 13. A modifier applying device may be provided in the section up to the portion, and the modifier may be applied to the reinforcing fiber sheet running downward in the vertical direction. Although omitted in FIG. 1b, a widening device and a smoothing device for the reinforcing fiber sheet, and a preheating device for the reinforcing fiber sheet can be appropriately used between the creel that unwinds the reinforcing fibers and the coating portion. Further, the order of the array device, the widening device, the smoothing device, and the preheating device can be changed as appropriate.

When the reinforcing fiber fabric is used, the creel 11 in FIG. 1b may be replaced with the reinforcing fiber fabric unwinding equipment, the arranging device 12 in FIG. 1 may be replaced with a nip roll, and the reinforcing fiber fabric may be pulled out.

<Running mechanism>
As a traveling mechanism for transporting the reinforcing fiber sheet or the prepreg of the present invention, a known roller or the like can be preferably used.

Further, in the present invention, in order to suppress the arrangement disorder and fluffing of the reinforcing fibers, it is preferable that the traveling path of the reinforcing fiber sheet is as straight as possible. In addition, the prepreg is often a sheet-like integral body that is a laminated body with a release sheet, but in the transport process of this, if there is a bent portion, wrinkles may occur due to the difference in peripheral length between the inner layer and the outer layer. Therefore, it is preferable that the traveling path of the sheet-like integrated object is as straight as possible. From this point of view, it is preferable to use a nip roll in the traveling path of the sheet-shaped integral body.

Whether to use the S-shaped roll or the nip roll can be appropriately selected according to the manufacturing conditions and the characteristics of the product.

<High-strength take-back device>
In the present invention, it is preferable to dispose a high-tensile take-up device for pulling out the primary prepreg from the coating portion downstream of the coating portion. This is because high frictional force and shear stress are generated between the reinforcing fiber sheet and the matrix resin in the coated portion, and in order to overcome them and pull out the prepreg, it is preferable to generate a high take-up tension downstream of the process. Is. As the high-tensile take-up device, a nip roll, an S-shaped roll, or the like can be used, but by increasing the frictional force between the roll and the prepreg, slippage can be prevented and stable running can be achieved. .. For this purpose, it is preferable to arrange a material having a high coefficient of friction on the roll surface, or to increase the nip pressure or the pressing pressure of the prepreg against the S-shaped roll. From the viewpoint of preventing slippage, the S-shaped roll is preferable because the frictional force can be easily controlled by the roll diameter, contact length, and the like.

<Release sheet supply device, winder>
In the production of prepregs and FRPs using the present invention, a release sheet feeder or a winder can be appropriately used, and known ones can be used as such, but any of them can be unwound or unwound. From the viewpoint of stable running of the seat, it is preferable to have a mechanism capable of feeding back the take-up tension to the take-up or take-up speed.

<Additional impregnation>
In order to adjust the degree of impregnation to a desired degree, it is also possible to combine the present invention with a means for further increasing the degree of impregnation by using an impregnation device separately after coating. Here, in order to distinguish from impregnation in the coating portion, additional impregnation after coating is referred to as additional impregnation, and a device for that purpose is referred to as a re-impregnation device. The apparatus used as the re-impregnation apparatus is not particularly limited, and can be appropriately selected from known ones according to the purpose. For example, as described in Japanese Patent Application Laid-Open No. 2011-132389 and WO2015 / 0602999 pamphlet, after preheating the laminate of the sheet-shaped carbon fiber bundle and the resin with a hot plate to sufficiently soften the resin on the sheet-shaped carbon fiber bundle. The impregnation can also proceed by using a device that pressurizes with a heated nip roll. The hot plate temperature for preheating, the surface temperature of the nip roll, the linear pressure of the nip roll, and the diameter and number of the nip roll can be appropriately selected so as to obtain a desired impregnation degree. It is also possible to use an "S-lap roll" in which the prepreg sheet runs in an S shape as described in the WO2010 / 150022 pamphlet. In the present invention, the "S-wrap roll" is simply referred to as an "S-shaped roll". WO2010 / 150022 Pamphlet Fig. 1 describes an example in which the prepreg sheet runs in an S shape, but if impregnation is possible, the contact length between the sheet and the roll, such as a U shape, a V shape, or a Λ shape. May be adjusted. Further, when the impregnation pressure is increased and the impregnation degree is increased, it is possible to add opposite contact rolls. Further, as shown in FIG. 4 of the WO2015 / 076981 pamphlet, it is possible to improve the impregnation efficiency and increase the production speed of the prepreg by arranging the conveyor belt facing the “S-lap roll”. Further, as described in WO2017 / 068159 Pamphlet, Japanese Patent Application Laid-Open No. 2016-203397, etc., it is possible to improve the impregnation efficiency by applying ultrasonic waves to the prepreg before impregnation and rapidly raising the temperature of the prepreg. be. Further, as described in Japanese Patent Application Laid-Open No. 2017-154330, it is also possible to use an impregnation device that vibrates a plurality of "squeezing blades" in the ultrasonic wave generator. It is also possible to fold and impregnate the prepreg as described in Japanese Patent Application Laid-Open No. 2013-22868.

<Simple re-impregnation>
In the above, an example of applying the conventional re-impregnation device is shown, but the temperature of the primary prepreg may still be high directly under the coating part, and in such a case, a long time has passed after leaving the coating part. If the additional impregnation operation is performed at the stage where the primary prepreg is not, the heating device such as a hot plate for reheating the primary prepreg can be omitted or simplified, and the impregnation device can be significantly simplified and miniaturized. The impregnation device located directly under the coating portion in this way is referred to as a simple re-impregnation device. A heated nip roll or a heated S-shaped roll can be used as the simple re-impregnation device, but the roll diameter, set pressure, and contact length between the primary prepreg and the roll can be reduced as compared with a normal impregnation device. Not only can it be miniaturized, but it can also reduce power consumption, which is preferable.

Further, it is preferable to attach a release sheet to the primary prepreg before the primary prepreg enters the simple re-impregnation device because the running performance of the primary prepreg is improved.

FIG. 23 shows an example of a process provided with a re-impregnation device. A simple re-impregnation device 453 is provided directly below the coating portion 430. Here, the simple re-impregnation device 453 shows an example of a nip roll, but it is preferable that the nip roller is provided with a heating mechanism. The number of stages of the nip roll can be appropriately selected depending on the purpose, but from the viewpoint of process simplification, 3 stages or less is preferable (an example of 2 stages is shown in FIG. 23). Further, it is preferable that the nip roller is provided with a drive device from the viewpoint that tension control of prepreg transfer is easy. The nip pressure can be adjusted as appropriate according to the desired impregnation degree.

Further, it is preferable that the surface of the nip roll is subjected to an appropriate mold release treatment so that the primary prepreg does not stick, or a mold release sheet is inserted between the primary prepreg and the nip roll (for simplification, the figure). 23 is not drawn). When inserting the release sheet between the primary prepreg and the nip roll, it is preferable to insert the release sheet from the coating portion 430 side and separate the release sheet from the primary prepreg with the roll on the high-tensile take-up device 444 side. The released mold sheet may be wound up as it is, or may be run on a circuit so as to be inserted again from the coating portion 430 side as it is.

Further, as the re-impregnation device, in addition to the nip roll, the above-mentioned "S-wrap roll", a fixing bar, or the like can also be used. It is also possible to use a non-contact heating device using infrared rays, a laser, or the like.

<Prepreg>
In the prepreg obtained by the production method of the present invention, the impregnation rate of the matrix resin is preferably 10% or more. The state of impregnation of the matrix resin can be confirmed by tearing the collected prepreg and visually observing the inside, and more quantitatively, for example, it can be evaluated by a peeling method. The impregnation rate of the matrix resin by the peeling method can be measured as follows. That is, the collected prepreg is sandwiched between adhesive tapes and peeled off to separate the reinforcing fibers to which the matrix resin is attached and the reinforcing fibers to which the matrix resin is not attached. Then, the ratio of the mass of the reinforcing fibers to which the matrix resin is attached to the mass of the entire charged reinforcing fiber sheet can be used as the impregnation rate of the matrix resin by the peeling method. Further, in a prepreg having a high degree of impregnation, the degree of impregnation can be evaluated by the water absorption rate due to the capillary phenomenon of the prepreg. Specifically, it can be calculated from the mass change when the prepreg is cut into 10 cm × 10 cm and one side thereof is immersed in water for 5 minutes according to the method described in Japanese Patent Publication No. 2016-510077. ..

In the description of the present invention, the reinforcing fiber sheet impregnated with the matrix resin derived from the coated portion is referred to as a primary prepreg, but as a term, the primary prepreg is a term belonging to the concept of prepreg. Needless to say.

<Prepreg width>
Since the prepreg, which is a kind of precursor of FRP, is a form of the prepreg obtained in the present invention, a case where the present invention is applied to FRP applications will be described below.

The width of the prepreg is not particularly limited, and may be as wide as several tens of cm to 2 m or as a tape having a width of several mm to several tens of mm, and the width can be selected according to the application. In recent years, in order to improve the efficiency of the prepreg laminating process, devices called ATL (Automated Tape Laying) and AFP (Automated Fiber Placement) that automatically laminate narrow prepregs and prepreg tapes have become widely used. It is also preferable that the width is suitable for this. In ATL, narrow prepregs having a width of about 7.5 cm, about 15 cm, and about 30 cm are often used, and in AFP, prepreg tapes having a width of about 3 mm to about 25 mm are often used.

The method for obtaining a prepreg having a desired width is not particularly limited, and a method of narrowly slitting a wide prepreg having a width of about 1 m to 2 m can be used. Further, in order to simplify or omit the slit step, the width of the coating portion used in the present invention can be adjusted so as to have a desired width from the beginning. For example, when producing a narrow prepreg having a width of 30 cm for ATL, the width of the outlet of the coating portion may be adjusted accordingly. Further, in order to efficiently manufacture this, it is preferable to manufacture the product with a product width of 30 cm, and when a plurality of such manufacturing devices are arranged in parallel, a plurality of such manufacturing devices are used, using the same traveling device / transport device, various rolls, and a winder. Line prepregs can be manufactured. As an example, FIG. 24 shows an example in which five coating portions are connected in the parallel direction. At this time, the five reinforcing fiber sheets 416 may pass through the five independent reinforcing fiber preheating devices 420 and the coating portion 430 to obtain the five primary prepregs 471, or the reinforcing fiber preheating may be obtained. The device 420 and the coating unit 430 may be integrated in the parallel direction. In this case, the coating portion 430 may be provided with five independent width regulating mechanisms and five coating portion outlet widths.

Further, in the case of prepreg tape, a tape-shaped reinforcing fiber bundle forms a reinforcing fiber sheet with about 1 to 3 threads, and the tape-shaped reinforcing fiber bundle is passed through a coating portion whose width is adjusted so that a desired tape width can be obtained. You can also get it by doing. In the case of prepreg tape, the accuracy of the tape width is often required from the viewpoint of controlling the lateral overlap of the tapes. Therefore, it is preferable to control the outlet width of the coating portion more strictly, and in this case, it is preferable that the above L, L2 and W satisfy the relationship of L ≦ W + 1 mm and / or L2 ≦ W + 1 mm. ..

<Slit>
The slitting method of the prepreg is not particularly limited, and a known slitting device can be used. After winding the prepreg once, it may be installed in the slit device again to perform slitting, or for efficiency, the slit process may be arranged continuously from the prepreg manufacturing process without winding the prepreg once. Further, in the slitting process, a wide prepreg having a width of 1 m or more may be directly slit to a desired width, or a narrow prepreg having a width of about 30 cm may be cut and subdivided, and then slit again to a desired width. good.

When a plurality of coated portions of the above-mentioned narrow prepreg and prepreg tape are arranged in parallel, a release sheet may be supplied independently of each, or one wide release sheet may be supplied to the release sheet. A plurality of prepregs may be laminated. The widthwise end of the prepreg thus obtained can be cut off and supplied to the ATL or AFP device. In this case, since most of the end to be cut off becomes a release sheet, the matrix resin component (resin component in the case of FRP) adhering to the slit cutter blade can be reduced, and the cleaning cycle of the slit cutter blade can be extended. There is also the merit of being able to do it.

<Modification (variation) and application of the present invention>
In the present invention, a plurality of coated portions can be used to further improve the efficiency and functionality of the manufacturing process.

For example, a plurality of coating portions can be arranged so that a plurality of prepregs are laminated. FIG. 25 shows, as an example, an example of a mode in which prepregs are laminated using two coating portions. The two primary prepregs 471 drawn from the first coating portion 431 and the second coating portion 432 pass through the turning roll 445 and are laminated together with the resin film 443 on the laminating roll 447 below the turning roll 445. It is preferable to position the release sheet between the prepreg and the turning roll because the prepreg can be prevented from sticking to the nip roll and the running can be stabilized. FIG. 16 illustrates an apparatus in which a release seat 446 is run on a circuit on two turning rolls 445. The direction change roll can be replaced with a direction change guide or the like that has been subjected to a mold release process. In FIG. 25, the high-tensile take-up device 444 is arranged after laminating the primary prepreg 471, but it is of course possible to arrange it before laminating. Although the drawing of the spray coating device and the curtain coating device is omitted in FIG. 25, they can be arranged at arbitrary positions after the formation of the primary prepreg.

By using such a laminated type prepreg, the efficiency of the prepreg laminating process can be improved, which is effective when, for example, a thick FRP is manufactured. Further, it is expected that the toughness and impact resistance of the FRP will be improved by laminating thin multi-layered prepregs in multiple layers, and by applying this manufacturing method, thin multi-layered prepregs can be efficiently obtained. Further, by easily laminating different types of prepregs, it is possible to easily obtain a heterobound prepreg with added functionality. In this case, it is possible to change the type and fineness of the reinforcing fiber, the number of filaments, the mechanical characteristics, the fiber surface characteristics, and the like. Further, different matrix resins (resins in the case of prepreg) can be used. For example, a heterobound prepreg in which prepregs having different thicknesses or those having different mechanical characteristics are laminated can be used. Further, a resin having excellent mechanical properties is applied to the first coating portion, a resin having excellent tack properties is applied to the second coating portion, and by laminating these, a prepreg capable of achieving both mechanical properties and tack properties can be easily obtained. Obtainable. On the contrary, it is also possible to arrange a resin having no tack property on the surface. Further, it is also possible to apply a particle-free resin in the first coating portion and a particle-containing resin in the second coating portion.

As another mode, as illustrated in FIG. 24 and described above, a plurality of coated portions are arranged in parallel with respect to the traveling direction of the reinforcing fiber sheet, that is, a plurality of coated portions are arranged in parallel in the width direction of the reinforcing fiber sheet. Can be done. This makes it possible to streamline the production of narrow-width or tape-shaped prepregs. Further, by changing the reinforcing fiber or the matrix resin for each coated portion, it is possible to obtain prepregs having different properties in the width direction.

Further, as another mode, a plurality of coated portions can be arranged in series with respect to the traveling direction of the reinforcing fiber sheet. FIG. 26 shows an example in which two coating portions are arranged in series. It is preferable to arrange a high-tensile take-up device 448 between the first coating portion 431 and the second coating portion 432 from the viewpoint of stabilizing the running of the reinforcing fiber sheet 416, but depending on the coating conditions and the take-back conditions downstream of the process. Can be omitted. Further, if the release sheet is positioned between the primary prepreg pulled out from the first coating portion and the high-tensile take-up device 448, it is possible to prevent the primary prepreg from sticking to the nip roll and stabilize the running. ,preferable. In FIG. 26, a device in which the high-tensile take-up device 448 is used as a nip roll and the release seat 446 is run on a circuit on two rolls is illustrated.

With such a series arrangement, the type of matrix resin can be changed in the thickness direction of the primary prepreg. Further, even if the same type of matrix resin is used, running stability and high-speed running performance can be improved by changing the coating conditions depending on the coating portion. For example, a resin having excellent mechanical properties is applied to the first coating portion, a resin having excellent tack properties is applied to the second coating portion, and by laminating these, a prepreg capable of achieving both mechanical properties and tack properties can be easily obtained. Obtainable. On the contrary, it is also possible to arrange a resin having no tack property on the surface. Further, it is also possible to apply a particle-free resin in the first coating portion and a particle-containing resin in the second coating portion. Although the drawing of the spray coating device and the curtain coating device is omitted in FIG. 26, they can be arranged at arbitrary positions after the formation of the primary prepreg.

As described above, some modes in which a plurality of coated portions are arranged have been shown, but the number of coated portions is not particularly limited and can be applied in various ways depending on the purpose. Of course, it is also possible to combine these arrangements. Further, various sizes and shapes of the coated portion and coating conditions (temperature, etc.) can be mixed and used.

As described above, the manufacturing method of the present invention is a manufacturing method that not only improves manufacturing efficiency and stabilizes, but also improves the performance and functionality of the product, and is also excellent in expandability.

<Matrix resin supply mechanism>
Although the matrix resin is stored in the coating portion in the present invention, it is preferable to appropriately replenish the matrix resin because the coating proceeds. The mechanism for supplying the matrix resin to the coating portion is not particularly limited, and a known device can be used. It is preferable that the matrix resin is continuously supplied to the coating portion because the upper liquid level of the coating portion is not disturbed and the running of the reinforcing fiber sheet can be stabilized. For example, the weight of the matrix resin can be supplied as a driving force from a tank for storing the matrix resin, or can be continuously supplied by using a pump or the like. As the pump, a gear pump, a tube pump, a pressure pump, or the like can be appropriately used depending on the properties of the matrix resin. When the matrix resin is solid at room temperature, it is preferable to provide a melter on the upper part of the reservoir. It is also possible to use a continuous extrusion machine or the like. Further, it is preferable to provide a mechanism capable of continuously supplying the matrix resin according to the coating amount so that the liquid level at the upper part of the coating portion of the matrix resin is as constant as possible. For this purpose, for example, a mechanism that monitors the liquid level height, the weight of the coated portion, and the like and feeds them back to the supply device can be considered.

The liquid supply mechanism used for spray coating and curtain coating can also be provided like the matrix resin supply mechanism.

<Online monitoring>
Further, in order to monitor the coating amount, it is preferable to provide a mechanism capable of online monitoring of the coating amount. There are no particular restrictions on the online monitoring method, and known methods can be used. For example, as a device for measuring the thickness, for example, a beta ray meter or the like can be used. In this case, it is possible to estimate the coating amount by measuring the thickness of the reinforcing fiber sheet and the thickness of the prepreg and analyzing the difference between them. The online-monitored coating amount is immediately fed back to the coating portion and can be used for adjusting the temperature of the coating portion and the gap D (see FIG. 2) of the narrowed portion 23. Of course, the coating amount monitoring can also be used as defect monitoring. As the thickness measurement position, for example, in FIG. 27, the thickness of the reinforcing fiber sheet 416 can be measured in the vicinity of the turning roll 419, and the thickness of the prepreg can be measured between the coating portion 430 and the turning roll 441. It is also preferable to perform online defect monitoring using infrared rays, near infrared rays, a camera (image analysis), or the like.

Hereinafter, the present invention will be described in more detail with specific examples of manufacturing the prepreg according to the present invention. The following is an example, and the present invention is not construed as being limited to the aspects described below.

FIG. 27 is a schematic view of an example of a prepreg manufacturing process / apparatus using the first manufacturing method of the present invention. The plurality of reinforcing fiber bobbins 412 are hung on the creel 411 and pulled out via the turning guide 413. At this time, the reinforcing fiber bundle 414 can be pulled out with a constant tension by the brake mechanism applied to the creel. The plurality of reinforcing fiber bundles 414 drawn out are arranged in an orderly manner by the reinforcing fiber arranging device 415 to form the reinforcing fiber sheet 416. In FIG. 27, only three threads are drawn for the reinforcing fiber bundle, but in reality, it can be one thread to several hundred threads, and the desired prepreg width and fiber basis weight can be adjusted. be. After that, it is conveyed vertically downward through a widening device 417 and a smoothing device 418, and a turning roll 419. In FIG. 27, the reinforcing fiber sheet 416 is linearly conveyed between the reinforcing fiber arranging devices 415 to the turning roll 419. The widening device 417 and the smoothing device 418 may be skipped as appropriate depending on the purpose, or the device may not be arranged. Further, the arrangement order of the reinforcing fiber arranging device 415, the widening device 417, and the smoothing device 418 can be appropriately changed according to the purpose. The reinforcing fiber sheet 416 travels vertically downward from the turning roll 419 and reaches the turning roll 441 via the reinforcing fiber preheating device 420 and the coating portion 430. As the coating portion 430, any coating portion shape can be adopted as long as the object of the present invention is achieved. For example, the shapes shown in FIGS. 2 and 6 to 9 can be mentioned. Further, if necessary, a bush may be provided as shown in FIG. Further, as shown in FIG. 11, a bar may be provided in the coating portion. The apparatus of FIG. 27 includes a spray coating device 481 and a curtain coating device 482 after the primary prepreg 471 is formed by the coating unit 430. In FIG. 27, the spray coating device 481 and the curtain coating device 482 are drawn on both sides of the primary prepreg, but either one side may be used, or only one of the spray coating device 481 and the curtain coating device 482 is used. You may change the order. Then, after spray coating and / or curtain coating, a release sheet 443 is applied and the sheet can be picked up by the high-tensile pick-up device 444. In FIG. 27, the nip roll is drawn as the high-tensile take-up device 444. After that, the sheet-like integral body is cooled by the cooling device 461 via the re-impregnation device 450 provided with the hot plate 451 and the heating nip roll 452, then is taken up by the taking-up device 462, and the upper release sheet 446 is peeled off. , A sheet-like integral body 472 made of a prepreg / release sheet to be a product can be obtained by winding with a winder 464. Since the sheet-like integral body is conveyed from the direction changing roll 441 to the winder 464 in a basic linear shape, the occurrence of wrinkles can be suppressed. In FIG. 27, the drawing of the matrix resin supply device and the online monitoring device is omitted.

FIG. 28 is a schematic view of another example of a prepreg manufacturing process / apparatus using the first manufacturing method of the present invention. In FIG. 28, since the creel to the coating portion 430 are the same as those in FIG. 27, drawing is omitted. In FIG. 28, after the primary prepreg 471 is formed, the release sheet 446 is applied and taken up by the high-tensile take-up device 444. Here, the high-tensile take-up device 444 shows an example of an S-shaped roll. Then, after the release sheet on the upper side is peeled off, coating can be performed using the spray coating device 481 and the curtain coating device 482. Only one of the spray coating device 481 and the curtain coating device 482 may be used, or the order may be changed. Then, after the upper release sheet is applied, additional impregnation is applied, the upper release paper is peeled off, and the sheet-like integral body of the prepreg / release sheet is wound up.

Next, the present invention will be described in more detail with respect to the second production method by giving specific examples of production.

FIG. 29a is a schematic view of an example of a prepreg manufacturing process using the present invention when a UD base material is used as the reinforcing fiber sheet. The plurality of reinforcing fiber bobbins 412 are hung on the creel 411 and pulled upward through the turning guide 413. At this time, the reinforcing fiber bundle 414 can be pulled out with a constant tension by the brake mechanism applied to the creel. The plurality of reinforcing fiber bundles 414 drawn out are arranged in an orderly manner by the reinforcing fiber arranging device 415 to form the reinforcing fiber sheet 416. In FIG. 29a, only three threads are drawn for the reinforcing fiber bundle, but in reality, it can be two threads to several hundred threads, and the desired prepreg width and fiber basis weight can be adjusted. be. After that, the reinforcing fiber sheet 422 to which the modifier is applied is obtained through the widening device 417, the smoothing device 418, and the modifier applying device 421. The reinforcing fiber sheet 422 to which the modifier is applied is conveyed vertically downward through the turning roll 419.

As the modifier applying device, it can be appropriately selected and used from various applying methods without limitation as long as the object of the present invention is achieved. For example, spray coating (including melt blow), curtain coating, and the like can be used.

FIG. 29a shows an example in which the reinforcing fiber sheet 416 is linearly conveyed between the reinforcing fiber arranging devices 415 to the modifier applying device 421. As the widening device 417 and the smoothing device 418, known ones can be used or skipped as appropriate depending on the purpose, or the device may not be arranged. Further, the arrangement order of the reinforcing fiber arranging device 415, the widening device 417, and the smoothing device 418 can be appropriately changed according to the purpose. The reinforcing fiber sheet 422 to which the modifier is applied runs vertically downward from the turning roll 419 and reaches the turning roll 441 via the reinforcing fiber preheating device 420 and the coating portion 430. The reinforcing fiber preheating device 420 may be skipped as appropriate depending on the purpose, or the device may not be arranged. As the coating portion 430, any coating portion shape can be adopted as long as the object of the present invention is achieved. For example, the shapes shown in FIGS. 2 and 6 to 9 can be mentioned. Further, if necessary, a bush may be provided as shown in FIG. Further, as shown in FIG. 11, a bar may be provided in the coating portion. In FIG. 12a, the release sheet 446 unwound from the release sheet (upper) supply device 442 can be laminated on the prepreg 471 on the turning roll 441 to form a sheet-like integral body. Further, the release sheet 446 unwound from the release sheet supply device 442 can be inserted into the lower surface of the sheet-like integral body. Here, a release paper, a release film, or the like can be used as the release sheet. This can be picked up by the high-tensile pick-up device 444. In FIG. 29a, the nip roll is drawn as the high-tensile take-up device 444. After that, the sheet-like integral body is cooled by the cooling device 461 via the re-impregnation device 450 provided with the hot plate 451 and the heating nip roll 452, then is taken up by the taking-up device 462, and the upper release sheet 446 is peeled off. , A sheet-like integral body 472 made of a prepreg / release sheet to be a product can be obtained by winding with a winder 464. Since the sheet-like integral body is conveyed from the direction changing roll 441 to the winder 464 in a basic linear shape, the occurrence of wrinkles can be suppressed. In FIG. 29a, the drawing of the matrix resin supply device and the online monitoring device is omitted.

FIG. 29b is an example of a prepreg manufacturing process using the present invention when a UD base material is used as the reinforcing fiber sheet, as in the example shown in FIG. 29a. The difference is that the place where the modifier is applied after changing from the horizontal direction to the vertical direction downward. Further, an example in which the modifier applying device 421 is installed after the reinforcing fiber preheating device 420 is shown. The arrangement order of the modifier applying device 421 and the reinforcing fiber preheating device 420 may be changed as appropriate, but when a low-viscosity resin is used as the modifier, the widening device 417, the smoothing device 418, and the reinforcing fiber preheating device 420 It is preferable to arrange the modifier applying device 421 later. As a result, it is possible to prevent contamination of the device and roll due to contact with the modifier applied to the reinforcing fiber sheet, and the modifier is heated by the reinforcing fiber preheating device 420 to increase the fluidity of the modifier, thereby increasing the fluidity of the modifier. It is possible to prevent the modifier from being dissolved in the matrix resin stored in 430. In FIG. 29b, the traveling direction of the reinforcing fiber sheet when applying the modifier is downward from the horizontal direction in the vertical direction, but the orientation of the modifier applying device may be changed by 90 degrees to apply the modifier. In FIG. 29b, the drawing of the matrix resin supply device and the online monitoring device is omitted.

Although FIGS. 29a and 29b show an example in which the modifier is applied to the reinforcing fiber sheet transported downward in the horizontal or vertical direction, it can also be applied on a roll that changes direction.

FIG. 30 is a schematic view of another example of a prepreg manufacturing process / apparatus using the present invention when a UD base material is used as the reinforcing fiber sheet. In FIG. 30, the reinforcing fiber bundle 414 is pulled out from the creel 411, the reinforcing fiber sheet 416 is formed as it is by the reinforcing fiber arranging device 415, and then the reinforcing fibers are linearly conveyed to the widening device 417 and the smoothing device 418, and then the reinforcing fibers are conveyed. It differs from FIG. 29b in that the sheet 416 is guided upward. With such a configuration, it is not necessary to install the device above, and the installation of the scaffolding or the like can be greatly simplified.

FIG. 31 is a schematic view of another example of a prepreg manufacturing process / apparatus using the present invention when a UD base material is used as the reinforcing fiber sheet. In FIG. 31, a creel 411 is installed on the floor to further straighten the traveling path of the reinforcing fiber sheet 416.

FIG. 32 is a schematic view of another example of a prepreg manufacturing process / apparatus using the present invention when a UD base material is used as the reinforcing fiber sheet. An example in which a simple re-impregnation device is used instead of the normal re-impregnation device shown in FIG. 29b is shown. In 32, since the simple re-impregnation device 453 is installed directly under the coating portion 430, the prepreg 471 is guided to the simple re-impregnation device 453 in a high temperature state, so that the impregnation device can be simplified and miniaturized. In FIG. 32, the heating nip roll 454 is drawn as an example, but of course, a small heating S-shaped roll or a non-contact heating device may be used depending on the purpose. It is also an advantage that the entire prepreg manufacturing apparatus can be made very compact by using the simple re-impregnation apparatus.

30, FIG. 31, and FIG. 32 are schematic views of another example of the prepreg manufacturing process / apparatus when a unidirectionally arranged reinforcing fiber bundle is used as the reinforcing fiber sheet as in FIG. 29b. By using the reinforcing fiber fabric roll for the unwinding device 412 and the nip roll for the 413, the device shown in each figure can be applied even when the reinforcing fiber fabric is used.

FIG. 33 shows an example in which 2 rolls-2 sets (4 in total) of a high-tensile take-up S-shaped roll 449 as a high-tensile take-up device and an “S-lap roll” type heated S-shaped roll 455 as a re-impregnation device are used. Although it is drawn, the number of rolls can of course be increased or decreased depending on the purpose. Further, although the contact roll 456 for enhancing the impregnation effect is also drawn in FIG. 33, it can of course be omitted depending on the purpose.

FIG. 34 is a schematic view of another example of the manufacturing process / apparatus of the prepreg using the present invention. In this example, an example in which an "S-lap roll" type heated S-shaped roll is also used as a high-tensile take-up device is shown. There is an advantage that the entire prepreg manufacturing apparatus can be made very compact.

Hereinafter, an example in which a thread cracking inhibitor is used will be described as a more specific example.

As the prepreg manufacturing apparatus, an apparatus having the configuration shown in FIG. 29a (the resin supply unit is omitted from the description), excluding the widening apparatus 417, the smoothing apparatus 418, and the re-impregnation apparatus 450 can be used.

(Granting anti-thread breakage agent)
The plurality of reinforcing fiber bobbins 412 can be hung on the creel 411 and can be pulled out upward via the turning guide 413. The plurality of drawn reinforcing fiber bundles 414 can be arranged in an orderly manner by the reinforcing fiber arranging device 415, and the reinforcing fiber sheet 416 can be formed. The modifier applying device 421 can be used to apply the thread cracking inhibitor to the formed reinforcing fiber sheet 416, and the reinforcing fiber sheet 422 to which the thread cracking inhibitor is applied can be obtained. The reinforcing fiber sheet 422 to which the thread breakage inhibitor is applied can be run by changing the traveling direction from the horizontal direction to the vertically downward direction through the direction changing roll 419, and passes through the coating portion 430 via the reinforcing fiber preheating device 420. Can be made to.

As the reinforcing fiber, carbon fiber (manufactured by Toray, "Trading Card (registered trademark)" T800S (24K)) or the like can be used. The number of reinforcing fiber bobbins can be changed according to the basis weight of the prepreg to be produced, but if the number of threads is 56, a prepreg with a general basis weight can be obtained.

(Method of applying anti-thread breakage agent)
As a method for applying the thread breakage inhibitor, any application device can be appropriately selected and used without limitation as long as the object of the present invention is achieved. For example, spray coating, curtain coating and the like can be used.

When spray coating is used, a thread cracking inhibitor can be applied as shown in FIGS. 35a and 35b. As shown in FIG. 35a, the spray nozzle 510 is installed so as not to be in contact with the reinforcing fiber sheet 416 at the upper part, and the modifier 500, which is a thread cracking preventive agent dropleted from the installed spray nozzle 510, is applied in the horizontal direction. It can be applied to the running reinforcing fiber sheet 416 on one side, and as shown in FIG. 35b, the thread cracking inhibitor can be applied to the reinforcing fiber sheet 416 as fine droplets by the spray nozzle 510. In addition to the spray nozzle, any agent that can atomize and spray the thread cracking inhibitor can be used. In FIG. 35a, the modifier 500, which is a thread cracking inhibitor, is applied to the reinforcing fiber sheet 416 on one side, but of course, the spray nozzle 510 can be arranged on both sides of the reinforcing fiber sheet 416 and applied to both sides. Although omitted in FIGS. 35a and 35b, the spray nozzle 510 can be provided with a mechanism for continuously supplying the modifier, and the basis weight of the modifier is the modifier supplied to the spray nozzle 510. It can be adjusted by the amount of. The modifier to be supplied can also be heated and melted.

When the melt blow method is used, a thread cracking inhibitor can be applied as shown in FIGS. 36a and 36b. As shown in FIG. 36a, a coating head 520 having a discharge portion is installed so as not to contact the reinforcing fiber sheet 416 at the upper part, and the modifier 500 for preventing thread cracking is discharged from the installed coating head 520 and discharged. By guiding the modified agent 500 to be formed by an air flow 521, the thread cracking inhibitor can be formed into a fibrous form and then applied to the reinforcing fiber sheet 416 on one side. As shown in FIG. 36b, the thread cracking inhibitor discharged by the coating head 520 is guided by an air flow, and is formed into a fibrous shape before reaching the reinforcing fiber sheet. Can be crossed and entangled and applied to the reinforcing fiber sheet. More specifically, as the melt blow method, a method as described in Japanese Patent Application No. 2018-511189 can be used. The coating head has a plurality of flow paths for distributing the thread cracking preventive agent supplied to the inside in the width direction, and a coating head having a structure for guiding the thread cracking preventive agent to the discharge portion can be used. The discharge portion of the coating head has a plurality of holes in the width direction, and the fiber diameter formed by discharge can be adjusted by adjusting the area of the holes. The coating interval can also be adjusted. In FIG. 36a, the modifier 500, which is a thread cracking inhibitor, is applied to the reinforcing fiber sheet 416 on one side, but of course, the coating head 520 can be arranged on both sides of the reinforcing fiber sheet 416 and applied to both sides. Although omitted in FIGS. 36a and 36b, the coating head is provided with a mechanism for continuously supplying the anti-thread cracking agent, and the basis weight of the anti-thread cracking agent is the amount of the anti-thread cracking agent supplied to the coating head. By adjusting the above, it is possible to add the desired yarn cracking preventive agent to the basis weight. A gear pump can also be used as the supply mechanism, and the basis weight of the thread cracking preventive agent to be applied can be adjusted by adjusting the supply amount according to the gear pump to be used and its rotation speed. The thread breakage inhibitor can be supplied by heating and melting.

When the curtain coating is used, the thread cracking inhibitor can be applied as shown in FIGS. 37a, 37b and 38a and 38b. As shown in FIG. 37a, the coating head 530 is installed so as not to be in contact with the reinforcing fiber sheet 416 at the upper part, and the modifier 500 in which the thread cracking inhibitor is discharged in a planar manner from the installed coating head 530 runs in the horizontal direction. It can be applied to one side of the reinforcing fiber sheet 416 to be used. The coating head may be installed so that the angle between the discharge direction of the thread cracking inhibitor and the transport direction of the reinforcing fiber sheet 416 is 80 ° or less, as in Japanese Patent Application No. 2018-511188. The coating head may be any as long as it can discharge the supplied thread cracking inhibitor in a planar manner, and a resin having a uniform thickness in the width direction can be ejected to form a planar or curtain-like film. .. More specifically, it is possible to use a structure in which the resin can be discharged from a slit having a uniform thickness and without interruption. Further, in FIG. 37a, the modifier 500, which is a thread cracking inhibitor, is applied to the reinforcing fiber sheet 416 on one side, but of course, the coating head 530 may be arranged on both sides of the reinforcing fiber sheet 416 and applied to both sides. can. By installing the coating head 530 on the direction changing roll 419 as shown in FIG. 38a, the angle between the discharge direction of the coating head and the transport direction of the reinforcing fiber sheet can be set to 80 ° or less. When the modifier is applied as shown in FIG. 38a, the diameter of the direction changing roll 419 can be increased to improve the workability at the start of applying the modifier and the stability of application. Although omitted in FIGS. 37a, 37b, 38a, and 38b, the coating head 530 is provided with a mechanism for continuously supplying the modifier, and the basis weight of the modifier is supplied to the coating head. By adjusting the amount of the modifier to be used, the modifier with the desired basis weight can be imparted. A gear pump can also be used as the supply mechanism, and the basis weight to be given can be adjusted by adjusting the supply amount according to the gear pump to be used and its rotation speed. Further, the modifier may be heated and melted to be supplied.

(Thread breakage preventive agent)
The basis weight of the thread cracking inhibitor to be applied can be ^{20 g / m 2 or less.} When the thread breakage preventive agent is applied intermittently, the maximum application interval of the thread breakage preventive agent in the longitudinal direction can be 30 mm or less.

Various resins can be used as the components of the thread breakage inhibitor, and the above-mentioned thermosetting resin, thermosetting resin curing agent, thermoplastic resin, polymer particles, or a combination thereof can also be used. As the thread cracking inhibitor, a molten resin that has been heated and melted or that is liquid at room temperature can be used. A solution or varnished product using a solvent can also be used.

Epoxy resin can also be used as the thermosetting resin. In particular, if the resin is fluid at room temperature, the heating device for melting with the modifier applying device can be simplified and simplified, and the resin impregnation into the reinforcing fiber sheet can easily proceed, so that it can be preferably used. As a commercial product of epoxy resin, if it is a liquid bisphenol A type epoxy resin, "jER (registered trademark)" 825, "jER (registered trademark)" 827, "jER (registered trademark)" 828, "Epicron ( "Registered trademark" 850 (manufactured by DIC Co., Ltd.), "Epoxy (registered trademark)" YD-128 (manufactured by Nippon Steel & Sumitomo Metal Chemical Co., Ltd.), DER-331 (manufactured by Dow Chemical Co., Ltd.), etc. can be used. As commercial products of liquid bisphenol F type epoxy resin, "jER (registered trademark)" 806, "jER (registered trademark)" 807, "jER (registered trademark)" 1750, "Epiclon (registered trademark)" 830 (DIC) (Manufactured by Nippon Steel & Sumitomo Metal Corporation), "Epoxy (registered trademark)" YDF-170 (manufactured by Nippon Steel & Sumitomo Metal Corporation), etc. can be used, and p-aminophenol is a commercially available liquid triglycidyl aminophenol. "Araldite (registered trademark)" MY0500, "Araldite (registered trademark)" MY0510 (manufactured by Huntsman Advanced Materials Co., Ltd.), "jER (registered trademark)" 630 (manufactured by Mitsubishi Chemical Co., Ltd.), etc. It is possible to use "Araldite (registered trademark)" MY0600, "Araldite (registered trademark)" MY0610 (all manufactured by Huntsman Advanced Materials Co., Ltd.) having m-aminophenol as a precursor.

A toughness improver can be mixed with these, and specifically, polyamide, polyimide, polyethersulfone, polyetherethersulfone, polyetherimide, polyphenylene oxide, polysulfone and the like can be used. Commercially available products of polyether sulfone include "Sumika Excel (registered trademark)" PES5003P (manufactured by Sumitomo Chemical Co., Ltd.) and "Virantage (registered trademark)" VW10700 (Solvay Advanced).
Polymers), "Sumika Excel (registered trademark)" PES7600P (Sumitomo Chemical Co., Ltd.), "Ultem (registered trademark)" 1010 (Sabic Innovative Plastics Co., Ltd.) as a commercial product of polyetherimide, As a commercially available product of polysulfone, "Virantage (registered trademark)" VW30500 (manufactured by Solvay Advanced Polymers Co., Ltd.) and the like can be used. It should be noted that not only the melted ones but also the particulate ones can be kneaded and used. It is also possible to mix the polymer particles described above.

Further, the thread cracking inhibitor is kneaded with a phosphorus atom-containing compound such as metal hydroxide, metal oxide, red phosphorus, phosphoric acid ester, and phosphate, a nitrogen-containing compound, and a flame retardant such as antimony trioxide. It can also be used.

(Application of matrix resin)
As shown in FIG. 29a, by passing the reinforcing fiber sheet 422 to which the modifier is applied through the coating portion 430, a prepreg coated with the matrix resin on both sides can be obtained.

As the coating portion, the coating portion 20c type coating portion of the form shown in FIG. 7 can be used.

Since the coating part is made of stainless steel and the matrix resin is further heated, a plate heater can be attached to the outer periphery of the coating part so that the temperature and viscosity of the matrix resin can be adjusted while measuring the temperature with a thermocouple. .. Further, the running direction of the reinforcing fiber sheet in the liquid pool portion is downward in the vertical direction, and the liquid pool portion has a two-step taper shape, but the first-step taper has an opening angle of 15 to 20 ° and the taper length (that is, H) is The opening angle of 10 to 70 mm and the second taper can be 5 to 10 °. Further, as the width regulating mechanism, a plate-shaped bush that matches the internal shape of the coating portion as shown in FIG. 5 is provided, and the installation position of the plate-shaped bush can be freely changed so that L2 can be adjusted as appropriate. Although it can be adjusted according to the desired basis weight, if L2 is 300 mm and the gap D of the narrowed portion is about 0.2 mm, a prepreg with a general basis weight can be obtained. Further, the outside of the bush can be closed on the exit surface of the narrowed portion so that the matrix resin does not leak from the outlet of the narrowed portion.

(Matrix resin)
As the matrix resin to be coated by the coating unit 430, a matrix resin which is a thermosetting epoxy resin composition can be used. This is a mixture of an epoxy resin (a mixture of an aromatic amine type epoxy resin + a bisphenol type epoxy resin), a curing agent (diaminodiphenyl sulfone), and a polyether sulfone, and does not contain polymer particles. The viscosity of this matrix resin can be measured using ARES-G2 manufactured by TA Instruments, and has a measurement frequency of 0.5 Hz, a heating rate of 1.5 ° C./min, 3675 Pa · s at 40 ° C., 50 Pa · s at 75 ° C., 90. It is 15 Pa · s at ° C. and 4 Pa · s at 105 ° C. Using this matrix resin, a prepreg can be produced by setting the matrix resin temperature of the coated portion to 75 to 105 ° C. and the traveling speed of the reinforcing fiber sheet and the prepreg to 5 to 25 m / min.

A thread cracking inhibitor is used as the modifier, and as a method for applying the thread cracking inhibitor, a melt blow method is used as shown in FIG. 36a with reference to the description of Japanese Patent Application No. 2018-511189, and the reinforcing fiber sheet 416 is used. A modifier 500, which is a thread cracking inhibitor, can be applied to the product. A coating head having a plurality of discharge holes in the width direction can be arranged in a non-contact state on the reinforcing fiber sheet 416 that is conveyed in the horizontal direction. Adjust the rotation speed of the gear pump that supplies the thread cracking preventive agent to the coating head, apply the thread cracking inhibitor with a grain of 10 g / m ^2, and apply the thread cracking inhibitor at a maximum of 30 mm in the longitudinal direction. The same components as the matrix resin are used as the components of the crack inhibitor, the temperature of the matrix resin in the coated portion is set to 90 ° C., the taper of the first step of the coated portion has an opening angle of 17 °, H = 70 mm, and the taper of the second step is opened. The angle can be 7 °. When the running speed of the reinforcing fiber sheet, the reinforcing fiber sheet to which the modifier is applied, and the prepreg is set to 20 m / min, the reinforcing fiber sheet can be continuously run for 30 minutes or more without thread clogging or thread breakage at the coated portion.

When the thread cracking inhibitor is not applied to the reinforcing fiber sheet, the thread cracking having a width of 2 mm or more is present and the quality is poor, and the thread cracking of the prepreg treated to prevent the thread cracking can be 2 mm or less, and the quality of the prepreg is good. Can be obtained. For thread cracking of the prepreg, the obtained prepreg is unwound for 10 m, and the maximum width of the thread cracked portion without reinforcing fibers is measured with a caliper.

Further, the impregnation rate of the obtained prepreg by the peeling method can be set to 50% or more. The impregnation rate by the peeling method is determined by sandwiching the collected prepreg with adhesive tape, peeling it off, separating the reinforcing fibers with the matrix resin attached and the reinforcing fibers without the matrix resin, and adding the total mass of the reinforcing fiber sheet. It is calculated from the ratio of the mass of the reinforcing fiber to which the matrix resin is attached to.

Further, the basis weight of 100 mm square in the width direction of the prepreg can be contained in the range of plus or minus 3% by mass for both the carbon fiber and the resin, and excellent basis weight uniformity in the width direction can be obtained. The basis weight uniformity of the prepreg in the width direction can be evaluated as follows. A prepreg having a width of 300 mm is cut out at the right end, the center, and the left end in a width direction of 100 mm square, and the mass of the prepreg and the mass of carbon fibers are measured at n = 3, respectively. The mass of carbon fibers is measured as a residue of resin eluted from the prepreg with a solvent. From this, the average value at each sampling position is calculated, and the average value at each sampling position is compared with each other.

Further, CFRP can be obtained by laminating 6 layers of this prepreg and curing it at 180 ° C. and 6 kgf / cm ^{2 (0.588 MPa) for 2 hours using an autoclave.} The tensile strength is about 2.9 GPa, and the prepreg obtained without applying the thread cracking inhibitor and the prepreg prepared by the conventional hot melt method using carbon fiber and matrix resin A are laminated and cured in the same manner. The tensile strength of the CFRP obtained in (1) is also about the same as about 2.9 GPa. The CFRP tensile strength is measured in the same manner as in the WO2011 / 118106 pamphlet, and a value obtained by normalizing the volume% of the reinforcing fibers in the prepreg to 56.5% is used.

Further, by applying the thread cracking inhibitor to the reinforcing fiber sheet 1a on only one surface of the upper surface, it is possible to prevent the thread cracking inhibitor applied to the reinforcing fiber sheet from adhering to the transport roll 419 and contaminating it. Can be done.

By adding a thread cracking inhibitor, it is possible to improve the thread cracking of the prepreg that is finally obtained without impairing the process stability. Obtainable.

<Prepreg manufacturing equipment>
The coating unit 20c type coating portion of the form shown in FIG. 7 was used, and the apparatus shown in FIG. 28 was used as the prepreg manufacturing apparatus. In FIG. 28, the drawing of a device such as a creel is omitted, and the reinforcing fiber preheating device and subsequent devices are drawn.

<Applying part>
As the coating portion, a stainless steel block was used for the wall surface member forming the liquid pool portion and the constricted portion, and a stainless steel plate was used for the side plate member. Further, in order to heat the matrix resin, a plate heater was attached to the outer periphery of the wall surface member and the side plate member, and the temperature and viscosity of the matrix resin were adjusted while measuring the temperature with a thermocouple. The running direction of the reinforcing fiber sheet is downward in the vertical direction, and the liquid pool is tapered in two steps. The upper taper has an opening angle of 17 °, the taper height (that is, H) is 100 mm, and the lower taper has an opening angle of 7 °. there were. Further, as the width regulating mechanism, a plate-shaped bush that matches the internal shape of the coating portion as shown in FIG. 5 is provided, and the installation position of the plate-shaped bush is freely changed so that L2 can be adjusted as appropriate. The width Y of the narrowed portion was set to 300 mm when L2 was 300 mm. The gap D of the narrowed portion was set to 0.18 mm. In this case, the aspect ratio of the exit slit is 1500. In addition, the outside of the bush was closed on the lower surface of the outlet of the stenosis so that the matrix resin would not leak from the outlet of the stenosis.

<Reinforced fiber sheet>
To prepare the prepreg, carbon fiber (manufactured by Toray Industries, Inc., "Treca (registered trademark)" T800S (24K)) is used as the reinforcing fiber, and the thermosetting epoxy resin composition described later is used as the matrix resin. A shape prepreg was prepared. The number of reinforcing fiber bobbins was changed according to the prepreg to be produced, but was set to 56 unless otherwise specified.

<Prepreg manufacturing process>
Reinforcing fiber bundles were pulled out from a plurality of reinforcing fiber bobbins hung on the creel, a reinforcing fiber sheet was formed by a reinforcing fiber arrangement device, and the reinforcing fiber sheet was once guided upward by a turning roll. After that, the reinforcing fiber sheet was conveyed vertically downward through a direction changing roll, heated to a temperature equal to or higher than the coating portion temperature by the reinforcing fiber preheating device, guided to the coating portion, and coated with the matrix resin. After that, the primary prepreg was pulled out from the coating portion, a release sheet was applied, and then the release sheet was taken up by a high-tensile take-up device, and the release sheet on the upper side was peeled off. Then, spray coating was performed on the table. After that, an upper release sheet was applied, which was guided to a re-impregnation device equipped with a hot plate and a heating nip roll, and in some cases, re-impregnation was performed. Then, the upper release paper was peeled off through a cooling device, and the sheet-like integral body of the prepreg / release sheet was wound up.

<Matrix resin>
Matrix resin (thermosetting epoxy resin composition):
It is a mixture of epoxy resin (a mixture of aromatic amine type epoxy resin + bisphenol type epoxy resin), curing agent (diaminodiphenyl sulfone), and polyether sulfone, and does not contain polymer particles. The viscosity of this thermosetting epoxy resin was measured using ARES-G2 manufactured by TA Instruments at a measurement frequency of 0.5 Hz and a heating rate of 1.5 ° C./min. At 75 ° C., 50 Pa · s, and 90 ° C. It was 15 Pa · s and 4 Pa · s at 105 ° C.

<Liquid for spray application>
A bisphenol type liquid epoxy resin was used. The viscosity of this liquid epoxy resin was measured using ARES-G2 manufactured by TA Instruments at a measurement frequency of 0.5 Hz and a temperature of 25 ° C. and found to be 10 Pa · s.

<Spray application conditions>
The coating head temperature was 25 ° C., the single hole area of the mouthpiece was 0.025 mm ² , the single hole discharge amount was 0.16 g / min, and the number of mouthpiece holes in the width direction was 220. Further, the air flow was 0.15 MPa, and the coating height h from the carbon fiber sheet to the lower surface (base surface) of the coating head was 50 mm.

<Evaluation of continuous running performance>
In order to evaluate the continuous running performance at the coated portion of the reinforcing fiber sheet, the running was continuously carried out for 30 minutes, and the one without fluff clogging and thread breakage was designated as "Good", and the one with fluff clogged and thread breakage was designated as "Bad".

Further, in order to evaluate the sign of fluff clogging, the coated portion was disassembled after continuous running for 60 minutes and 120 minutes, and the wetted surface of the wall surface member was visually observed to check for the presence or absence of fluff. Those with fluff attached near the stenosis after continuous running are fluff-preventive "Poor", and those with fluff attached to the part far from the stenosis 23 (near the upper part of the liquid pool 22) after continuous running The fluff prevention property was evaluated as the fluff prevention property "Fair" and the fluff prevention property "Good" when the wall surface member 21 had no fluff adhered to the wetted surface after continuous running.

In addition, after running continuously for 60 minutes at a running speed of 20 m / min, the fiber bundle is cracked (the part where the sheet-shaped carbon fiber bundle is torn in a vertical stripe shape) and the end of the fiber bundle is broken in the reinforcing fiber sheet directly above the liquid pool. The time during which the carbon fiber bundles were running uniformly without overlapping (the part where the carbon fiber bundles overlapped) was measured. "Excellent" means that the ratio of running time uniformly without cracking of the fiber bundle and the end of the fiber bundle occupies 90% or more of the total running time, and "Good" means that the running time is 50% or more and less than 90%. , 10% or more and less than 50% was designated as "Fair", and those less than 10% were designated as "Poor".

<Evaluation of impregnation degree>
・ Peeling method (when the degree of impregnation is low)
The collected prepreg was sandwiched between adhesive tapes and peeled off to separate the reinforcing fibers to which the matrix resin was attached and the reinforcing fibers to which the matrix resin was not attached. Then, the ratio of the mass of the reinforcing fibers to which the matrix resin was attached to the mass of the entire charged reinforcing fiber sheet was defined as the impregnation rate of the matrix resin by the peeling method.

・ Water absorption rate (when the degree of impregnation is high)
According to the method described in Japanese Patent Publication No. 2016-510077, the prepreg was cut into 10 cm × 10 cm, and one side thereof was calculated from the mass change when immersed in water for 5 minutes.

[Examples 1 to 4]
A prepreg was prepared by using the thermosetting epoxy resin composition (matrix resin) in the coating portion and using the liquid epoxy resin in the spray coating. However, in this example, additional impregnation was not performed after spray application. The temperature of the matrix resin in the liquid pool was set to 90 ° C. (equivalent to 15 Pa · s). The running speed of the reinforcing fiber sheet and the prepreg was set to 20 m / min.

Relationship between the width L2 at the lower end of the width regulation mechanism and the width W of the primary prepreg The running of the primary prepreg at the coating portion when the height H at which the cross-sectional area between L2-W and the coating portion continuously decreases is changed. The stability evaluation results are shown in Table 1. From this, it can be seen that the smaller L2-W and the larger H, the better the stable running performance of the primary prepreg. In addition, when the primary prepreg was collected at the lower part of the simple re-impregnation device without performing the simple re-impregnation and the impregnation rate was examined by the peeling method, all of them were 50 to 60%, and the impregnation was progressing at the coated part. It was confirmed. In addition, the basis weight uniformity in the width direction of the primary prepreg collected as described above was evaluated as follows. A prepreg having a width of 300 mm was cut out at the right end, the center, and the left end in a width direction of 100 mm square, and the mass of the prepreg and the mass of the carbon fiber were measured at n = 3, respectively. The mass of the carbon fibers was measured as a residue obtained by eluting the resin from the prepreg with a solvent. From this, when the average value at each sampling position was calculated and the average value at each sampling position was compared, both carbon fiber and resin were within the range of plus or minus 2% by mass, and excellent texture uniformity was achieved. Met. In addition, due to the effect of the spray-applied liquid, the tackiness of the prepreg surface was also excellent.

[Comparative Example 1]
As the coating portion, a prepreg having no portion (H = 0) at which the cross-sectional area shown in FIG. 10 continuously decreases was used, and an attempt was made to prepare a prepreg in the same manner as in Example 1 under the conditions shown in Table 1, but 20 m / Immediately after the start of running in minutes, the reinforcing fiber sheet was clogged, and the continuous running performance was poor.

[Example 5]
After applying the matrix resin under the conditions of Example 1, spray coating was performed, and the mixture was further guided to a re-impregnation device to perform re-impregnation. When the water absorption rate of this prepreg was examined, it was 5%, which was a sufficient impregnation degree.

Next, 6 layers of the obtained prepreg were laminated and ^{cured at 180 ° C. and 6 kgf / cm 2} (0.588 MPa) for 2 hours using an autoclave to obtain CFRP. All of the obtained CFRPs had a tensile strength of 3.0 GPa and had mechanical properties suitable as structural materials for aerospace. The CFRP tensile strength was measured in the same manner as in the WO2011 / 118106 pamphlet, and a value obtained by normalizing the volume% of the reinforcing fibers in the prepreg to 56.5% was used.

[Reference example 1]
Prepreg prepared by the conventional hot melt method using carbon fiber and thermosetting epoxy resin (matrix resin) is cured at 180 ° C. at 6 kgf / cm ² (0.588 MPa) for 2 hours using an autoclave. The intensity was 2.9 GPa.

The prepreg obtained by the manufacturing method of the present invention is an FRP represented by CFRP, which is used for aerospace applications, structural materials and interior materials for automobiles, trains, ships, etc., pressure vessels, industrial materials, sports materials, medical equipment. It can be widely applied to applications, housing applications, civil engineering / building applications, etc.

1 Reinforcing fiber 1a Reinforcing fiber sheet 1b Reinforcing fiber sheet to which a modifier is applied 1c Primary prepreg 1d Prepreg 2 Matrix resin 3, 3a, 3b Release sheet 11 Creel 12 Arranging device 13, 14 Conveying roll 15 Winding device 16 , 16a, 16b Supply device 20 Coating part 20b Coating part 20c of another embodiment Coating part 20d of another embodiment Coating part 20e of another embodiment Coating part 21a, 21b Wall member 21c, 21d Separately Wall members 21e, 21f of different shapes Wall members 21g, 21h of different shapes Wall members 21i, 21j of different shapes 22 Liquid pools 22a The cross-sectional area of the liquid pools is continuously reduced. Area 22b Area where the cross-sectional area does not decrease in the liquid pool 22c Area where the cross-sectional area decreases intermittently in the liquid pool 23 Constriction 24a, 24b Side plate member 25 Outlet 26 Gap 27, 27a, 27b Width regulation mechanism 28 Revised Pawnbroker 30 Coating parts 31a, 31b of Comparative Example 1 Wall member 32 of Comparative Example 1 Liquid pool portion 33 of Comparative Example 1 A region 35a, 35b of the liquid pool portion of Comparative Example 1 in which the cross-sectional area is intermittently reduced. , 35c Bar 41 Spray coating device 42 Curtain coating device 43 Liquid 44 Air flow 45 Table 46 Liquid or solidified product thereof or a mixture thereof 47 Film 48 End air 49 Surface air 50 Roll 100 Coating device B Depth C of liquid pool 22 Height to the upper liquid level of the liquid pool 22 D Gap in the constriction G Position where width regulation is performed H Vertical height where the cross-sectional area of the liquid pool 22 continuously decreases L Width R of the liquid pool 22 Ra, Rb Swirl flow T Circulating flow W Width of the primary prepreg 1b measured directly under the constriction portion Y Width of the constriction portion 23 Z Reinforcing fiber sheet, transport direction of the primary prepreg and prepreg θ Opening angle E end of the tapered portion Part air blowing direction F Surface part Air blowing direction N Neck-in h Coating height α Coating angle 411 Claire 412 Reinforcing fiber bobbin 413 Direction change guide 414 Reinforcing fiber bundle 415 Reinforcing fiber arranging device 416 Reinforcing fiber sheet 416'Modifier Reinforced fiber sheet 417 Widening device 418 Smoothing device 419 Directional change roll 420 Reinforcing fiber preheating device 421 Modulator applying device 422 Reinforcing fiber sheet with modifier 430 Coating part 431 Table 441 Directional change roll 442 Release type Sheet supply mechanism 443 Release sheet 44 4 High-tension take-up device 445 Direction change roll 446 Release sheet 447 Laminated roll 448 High-tension take-up device 449 High-tension take-back S-shaped roll 450 Re-impregnation device 451 Hot plate 452 Heating nip roll 453 Simple re-impregnation device 454 Heating nip roll 455 Heating S-shaped roll 456 Contact roll 461 Cooling device 462 Picking device 463 Release sheet (top) Winding device 464 Winder 471 Primary prepreg / prepreg 472 Sheet-like integral 481 Spray coating device 482 Curtain coating device 500 Deformer 510 Spray Nozzle 520 Coating head 521 Air flow 530 Coating head

Claims (14)

A spray coating is applied in which the reinforcing fiber sheet is passed through the coating portion in which the matrix resin is stored to apply the matrix resin to the reinforcing fiber sheet, and then the liquid is further discharged to the primary prepreg drawn from the coating portion. This is a method of manufacturing a prepreg, wherein the coating portion is provided with a liquid pool portion and a constricted portion which are communicated with each other, and the liquid pool portion is a portion where the cross-sectional area continuously decreases along the traveling direction of the reinforcing fiber sheet. A method for producing a prepreg, wherein the narrowed portion has a slit-shaped cross section and has a cross-sectional area smaller than that of the upper surface of the liquid pool portion. A curtain coating is applied in which the reinforcing fiber sheet is passed through the coating portion in which the matrix resin is stored to apply the matrix resin to the reinforcing fiber sheet, and then the liquid is further discharged to the primary prepreg drawn from the coating portion. This is a method of manufacturing a prepreg, wherein the coating portion is provided with a liquid pool portion and a constricted portion which are communicated with each other, and the liquid pool portion is a portion where the cross-sectional area continuously decreases along the traveling direction of the reinforcing fiber sheet. A method for producing a prepreg, wherein the narrowed portion has a slit-shaped cross section and has a cross-sectional area smaller than that of the upper surface of the liquid pool portion. This is a method for manufacturing a prepreg in which a reinforcing fiber sheet is passed through a coating portion in which the matrix resin is stored to apply the matrix resin to the reinforcing fiber sheet. The liquid pool portion has a portion in which the cross-sectional area continuously decreases along the traveling direction of the reinforcing fiber sheet, and the constricted portion has a slit-shaped cross section and is smaller than the upper surface of the liquid pool portion. At least one modification selected from the group consisting of a thread cracking inhibitor, a toughness improver, a flame retardant and a fluff sizing agent, having a cross-sectional area and before passing the reinforcing fiber sheet through the inside of the coating part. A method for producing a prepreg to which an agent is applied. The method for producing a prepreg according to claim 3, wherein the modifier is applied so that the basis weight of the modifier is 20 g / m ^{2 or less in the reinforcing fiber sheet after the application.} The method for producing a prepreg according to claim 3 or 4, wherein the modifier is applied intermittently in the longitudinal direction of the reinforcing fibers or so that the coating interval is within 30 mm at the maximum. The method for producing a prepreg according to any one of claims 3 to 5, wherein the modifier is a thread cracking inhibitor. 3. The method for producing a prepreg according to any one of the following items. A width regulating mechanism for regulating the width of the reinforcing fiber sheet is provided in the liquid pool portion, and the width (W) of the primary prepreg directly under the narrowed portion and the width regulated by the width regulating mechanism at the lower end of the width regulating mechanism (L2). The method for producing a prepreg according to any one of claims 1 to 7, wherein the relationship with the above satisfies L2 ≦ W + 10 (mm). The method for producing a prepreg according to any one of claims 1 to 8, wherein the height of the portion of the liquid pool where the cross-sectional area continuously decreases is 10 mm or more in the vertical direction. The method for producing a prepreg according to any one of claims 1 to 9, wherein the reinforcing fiber sheet is passed through the inside of the coated portion substantially downward in the vertical direction. The method for producing a prepreg according to any one of claims 1 to 9, wherein a reinforcing fiber sheet is passed through the inside of the coated portion in a horizontal direction or an inclined direction. A method for producing a prepreg, which further impregnates the prepreg obtained by the method for producing a prepreg according to any one of claims 1 to 11. A method for producing a prepreg tape for slitting a prepreg obtained by the method for producing a prepreg according to any one of claims 1 to 12. A method for producing a fiber-reinforced composite material for molding a prepreg obtained by the method for producing a prepreg according to any one of claims 1 to 12 or a prepreg tape obtained by the method for producing a prepreg tape according to claim 13. ..

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