WO2020040152A1 - Release sheet-provided multilayer structure prepreg, prepreg roll, prepreg tape, and composite material - Google Patents

Abstract

Regarding a prepreg having a non-impregnated portion left, the present invention addresses the problem of providing a prepreg capable of achieving sufficient vacuum moldability and handleability. The release sheet-provided multilayer structure prepreg is obtained by bonding a release sheet to the upper surface and/or the lower surface of a multilayer structure prepreg which has layered therein, in an alternate manner, non-impregnated layers and impregnated layers each obtained by impregnating a reinforcing fiber sheet with a matrix resin, wherein: the upper surface and the lower surface of the multilayer structure prepreg are formed of impregnated layers; and the inner layer portion of the multilayer structure prepreg excluding the upper surface and the lower surface includes at least one non-impregnated layer.

Description

Multi-layer prepreg, prepreg roll, prepreg tape and composite material with release sheet

The present invention relates to a prepreg that can achieve both vacuum pressure formability and handleability.

Fiber reinforced composite material (FRP), which is a matrix resin containing thermoplastic resin and thermosetting resin reinforced with reinforcing fibers, is a material for aviation and space, automotive material, industrial material, pressure vessel, building material, housing, medical equipment. It is used in various fields such as applications and sports. Particularly when high mechanical properties and lightness are required, carbon fiber reinforced composite materials (CFRP) are widely and suitably used.

FRP is obtained by impregnating a reinforcing fiber with a matrix resin to obtain an intermediate substrate. Among the intermediate base materials, sheet-like prepregs are widely used. In this case, prepregs are laminated and molded to produce FRP, but those containing a thermosetting resin as a matrix resin are not included in the molding process. Requires heat curing. Conventionally, an autoclave has been used for heat curing, and since the resin flows appropriately in the prepreg during the curing process due to heating and pressing, voids are not easily formed in the FRP, and FRP having excellent mechanical properties can be obtained. . However, since an autoclave is a pressure vessel, an autoclave that can process large materials for aerospace has a large initial investment, and a molding method that does not use an autoclave has been required.

Therefore, as described in Patent Literature 1, vacuum pressure forming using a vacuum oven, which requires a relatively small initial investment and is easy to increase in size, is being studied. However, in vacuum pressure molding, since the pressure difference for promoting the impregnation of the matrix resin is 1 atm or less, the impregnation time is longer than that in autoclave molding, and volatile components in the matrix resin are easily vaporized during heating. There was a problem that voids easily remained in the inside. Further, in order to reduce the voids, it was necessary to further lengthen the time under heating vacuum. For this reason, as described in Patent Literature 1, the vacuum pressing method is improved to shorten the impregnation time, and as described in Patent Literatures 2 and 3, prepregs that intentionally leave unimpregnated portions are laminated. Thus, studies have been made to form a degassing path, thereby promoting the removal of volatiles and suppressing the generation of voids.

JP 2017-179357 A International Publication WO2012 / 135754 pamphlet US Patent No. 6,139,942

However, in the prepregs in which the unimpregnated portions described in Patent Documents 2 and 3 are left, the unimpregnated portions are concentrated in the center portion of the prepreg. Since the carbon fibers to which the matrix resin does not adhere are apt to fall apart, the prepreg tends to have poor shape stability, such as peeling or displacement in the unimpregnated portion. For this reason, during the prepreg manufacturing process or during the step of finally winding the prepreg into a roll shape, the prepreg sheet or prepreg roll tends to have a defective shape. Also, in the prepreg cutting or slitting process, fluff of the reinforcing fiber may be generated from the unimpregnated portion of the cut surface, or in the prepreg laminating process, when using a wide prepreg, the unimpregnated portion during the laminating operation. However, troubles such as peeling and displacement occurred easily.

Further, in recent years, in order to increase the efficiency of the prepreg laminating process, devices called ATL (Automated Tape Laying) and AFP (Automated Fiber Placement) for automatically laminating narrow prepregs and prepreg tapes have been widely used. However, as the automatic laminating speed was increased, problems such as deformation and peeling of the prepreg tape could occur. As described above, in the conventional prepreg in which the unimpregnated portion is left in the central portion, there is a problem that the handleability in the prepreg manufacturing process, the prepreg roll storage process, the prepreg cutting / slit, the lamination process, and the like is likely to be poor. .

プ リ Thus, a prepreg excellent in handleability while leaving an unimpregnated portion for forming a degassing path has not yet been established.

課題 An object of the present invention is to provide a prepreg which can achieve both vacuum pressure formability and handleability with respect to a prepreg having an unimpregnated portion.

The prepreg of the present invention that solves the above-mentioned problems has a multilayer structure prepreg in which a reinforcing fiber sheet is impregnated with a matrix resin and a non-impregnated layer are alternately laminated. The multilayer prepreg, which is constituted by an impregnated layer, has at least one impregnated layer in an inner layer portion excluding an upper surface and a lower surface, and a release sheet is bonded to one or both surfaces of the upper surface and the lower surface of the multilayer structure prepreg. And a multi-layer prepreg with a release sheet.

プ リ The prepreg roll of the present invention is formed by winding the multilayer prepreg with the release sheet. Further, a prepreg tape having a width of 30 mm or less according to the present invention comprises the above-mentioned multilayer prepreg. Further, the composite material of the present invention is obtained by molding the above-mentioned multilayer prepreg, prepreg roll or prepreg tape with a release sheet.

Further, a liquid pool portion having a portion in which a matrix resin as a coating liquid is stored and having a cross-sectional area continuously reduced vertically downward, and a narrow portion having a slit-shaped outlet communicating with a lower end of the liquid pool portion, A method for producing a prepreg in which a reinforcing fiber sheet is passed downward in a vertical direction to an application section comprising: a prepreg for applying a coating liquid to the reinforcing fiber sheet. And a step of unifying the plurality of reinforcing fiber sheets inside the application section after the introduction, and a method of manufacturing a prepreg.

ADVANTAGE OF THE INVENTION According to the prepreg of this invention, it becomes possible to achieve both the reduction of the void at the time of vacuum-pressure molding, and the handleability of a prepreg, and to exhibit favorable mechanical characteristics especially in the vacuum-pressure molding of large members for aerospace. Can be.

1 is a cross-sectional photograph of a multilayer prepreg according to an embodiment of the present invention. FIG. 2 is a cross-sectional photograph of a multilayer prepreg of another embodiment different from FIG. 1. FIG. 3 is a schematic view according to an embodiment of a manufacturing method for manufacturing a multilayer prepreg of the present invention. FIG. 4 is a schematic diagram relating to a manufacturing method for manufacturing a multilayer prepreg of the present invention in another embodiment different from FIG. 3. FIG. 4 is an enlarged detailed cross-sectional view of a coating section 20 in FIG. 3. FIG. 4 is a bottom view of the application unit 20 in FIG. 3 when viewed from the direction of A in FIG. 3. FIG. 4 is a cross-sectional view illustrating a structure of an inner layer portion of the application section when the application section 20 in FIG. 3 is viewed from a direction B in FIG. 3. FIG. 8 is a cross-sectional view illustrating a flow of a matrix resin 4 in a gap 26 in FIG. 7. It is a figure showing an example of installation of a width regulation mechanism. FIG. 4 is a detailed cross-sectional view of a coating unit 20b according to another embodiment different from FIG. 3. It is a detailed cross-sectional view of the application part 20c of another embodiment different from FIG. FIG. 11 is a detailed cross-sectional view of a coating unit 20d according to another embodiment different from FIG. 10. It is a detailed cross-sectional view of the application part 20e of another embodiment different from FIG. It is a detailed cross-sectional view of the application part 30 of the embodiment different from the present manufacturing method. FIG. 4 is an enlarged detailed cross-sectional view of a coating section 20 in FIG. 3. FIG. 16 is a detailed cross-sectional view of a coating unit 20a of another embodiment different from FIG. FIG. 10 is a detailed diagram for explaining the arrangement of the width direction regulating member with reference to the diagram of FIG. FIG. 3 is a detailed cross-sectional view of a coating unit 20f according to an embodiment of the present invention. FIG. 4 is a detailed cross-sectional view of an application unit 40 and the vicinity thereof showing an embodiment different from the present invention.

望 ま し い A preferred embodiment of the present invention will be described below. Note that the following description exemplifies embodiments of the present invention, and the present invention is not construed as being limited thereto, and various modifications can be made without departing from the objects and effects of the present invention. .

FIG. 1 shows a cross-sectional photograph of a prepreg having a multilayer structure according to an embodiment of the present invention. In FIG. 1, the layer structure has an impregnated layer / unimpregnated layer / impregnated layer / unimpregnated layer / impregnated layer from the upper layer. This is a structure in which the impregnated layers are arranged on the outer and inner layers in the prepreg cross section, and the unimpregnated layers are arranged on the upper and lower surfaces of the center impregnated layer. It is the smallest unit. In the present invention, the impregnated layer includes a case where two impregnated layers are formed by joining with a matrix resin.

By arranging the impregnating layer on the outside, the tackiness of the prepreg is secured, and the sticking property in the prepreg laminating step is improved. Particularly, in order to increase the efficiency of the prepreg laminating process, devices called ATL (Automated Tape Laying) and AFP (Automated Fiber Placement) for automatically laminating narrow prepregs and prepreg tapes have been widely used in recent years. In this process, tackiness of the prepreg is very important. In addition, the adhesiveness between the multilayer prepreg and the release sheet is improved, and peeling of the multilayer prepreg from the release paper can be suppressed.

On the other hand, by having an impregnated layer also on the inner layer part of the prepreg cross section, the prepreg inner layer part is fixed with the impregnated layer, the reinforcing fibers in the prepreg are prevented from falling apart, and the prepreg is peeled off at the unimpregnated part or shifted. Of the prepreg can be suppressed, and the shape retention of the prepreg can be ensured. Further, by fixing the prepreg inner layer portion with the impregnated layer, even if the prepreg has an unimpregnated portion, appropriate stiffness is given to the prepreg, and handleability of the prepreg is improved. As described above, by having the layer structure of the present invention, even if it has an unimpregnated layer, it is possible to realize good shape retention and handleability of the prepreg without impairing the handleability of the prepreg. .

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, polyamide fibers, polyester fibers, and the like). However, it is preferable to use carbon fibers from the viewpoint of the mechanical properties and light weight of the FRP.

The reinforcing fibers can be subjected to a prepreg manufacturing process as a reinforcing fiber sheet in which the reinforcing fibers are arranged to form a sheet. At this time, 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, a reinforcing fiber is arranged in multiple axes, or a sheet is formed by random arrangement. Reinforced fiber fabric. Specific examples of the reinforcing fiber fabric include, in addition to woven fabric and knitted fabric, those in which reinforcing fibers are two-dimensionally arranged in a multiaxial manner, and those in which reinforcing fibers such as nonwoven fabric, mat, and paper are randomly oriented. In this case, the reinforcing fibers can be formed into a sheet using a method such as binder application, entanglement, welding, or fusion. As the woven fabric, a non-crimp woven fabric, a bias structure, an entangled woven fabric, a multiaxial woven fabric, a multiple woven fabric, or the like can be used in addition to the plain woven fabric, twill fabric, and satin woven fabric. The woven fabric combining the bias structure and the UD substrate not only suppresses the deformation of the woven fabric due to the tension in the coating / impregnation process due to the UD structure, but also has the pseudo-isotropy due to the bias structure, which is a preferable form. . In addition, the multi-layered fabric has an advantage that the structure and characteristics of the upper and lower surfaces of the fabric and the inner layer of the fabric can be designed. In the case of a knitted fabric, warp knitting is preferred in consideration of the shape stability in the coating / impregnation step, but a blade which is a tubular knitted fabric may be used.

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

The multilayer structure prepreg of the multilayer structure prepreg with a release sheet of the present invention is a multilayer structure prepreg obtained by impregnating a reinforcing fiber sheet with a matrix resin, and at this time, an impregnated layer impregnated with a matrix resin, It is important to have a structure in which an unimpregnated layer having no or insufficient impregnation is laminated. Here, an impregnated part and an unimpregnated part are first defined. The impregnated portion refers to a portion where the matrix resin is attached to the reinforcing fiber and a portion where only the matrix resin is present, while the non-impregnated portion refers to a portion where the matrix resin is not attached to the reinforcing fiber and the reinforcing fiber is not The exposed portion (dry reinforcing fiber portion) and the void portion where neither the reinforcing fiber nor the matrix resin is present. The impregnated layer and the non-impregnated layer are defined in the prepreg cross section when the prepreg is cut in the thickness direction. In the present invention, the cross section in the prepreg thickness direction is simply referred to as a prepreg cross section. In the present invention, the impregnated layer is a region having a horizontal unimpregnated portion ratio of less than 7%, which will be described later, in the prepreg cross section, and the unimpregnated layer is a region having a horizontal unimpregnated portion ratio of 7% or more. .

The unimpregnated portion ratio is determined by the following procedure. The prepreg section for this can be obtained, for example, as follows. That is, the prepreg is frozen in a freezer at −18 ° C., taken out of the freezer, and then quickly cut with a cutter at room temperature to obtain a prepreg cross section. Using a scanning electron microscope (SEM) or the like, a photograph of the cross section of the prepreg is taken as follows. That is, the upper surface and the lower surface of the prepreg are in the same field of view, and the lines of the upper surface or the lower surface of the prepreg are aligned in the horizontal direction of the photograph as much as possible. The vertical size of the prepreg cross-sectional photograph is set to 250 to 600 μm, and the horizontal size is set to 350 to 900 μm. If the cross section of the prepreg does not fit in this size, the photograph may be divided into a plurality of sheets. In the photograph of the cross section of the prepreg, a reference line is drawn in the horizontal direction so as to be in contact with the upper surface of the prepreg, and a horizontal auxiliary line is drawn every 10 μm in the vertical direction (vertical direction). Then, the length (L _U ) of the unimpregnated portion on the horizontal auxiliary line is measured. Next, to measure the length of the prepreg portion in the horizontal extension line of the (L _P). Then, the non-impregnated portion ratio (%) = (L _U / L _P ) × 100 (%) is obtained. Then, the unimpregnated portion ratio obtained by a certain horizontal auxiliary line is defined as the unimpregnated portion ratio of the upper and lower 5 μm above the horizontal auxiliary line, that is, the band-shaped region having a thickness of 10 μm. Thus, the boundary between the impregnated layer and the non-impregnated layer is an intermediate portion between the horizontal auxiliary lines having an unimpregnated portion ratio of less than 7% and the horizontal auxiliary lines having a non-impregnated portion ratio of 7% or more.

In the present invention, it is important that the prepreg section slices are prepared at three different points, and that the layer structure of the present invention is formed in all of the prepreg section photographs. Although the minimum unit of the layer structure of the present invention is five layers, it may be seven layers or more depending on the location. In addition, as long as all three different points have the layer structure of the present invention, the layer thickness or the position of the layer in the prepreg thickness direction may be different for each of the different three points, or the number of layers may be different. It may be different.

最大 In the non-impregnated layer, it is advantageous and preferable that the maximum value of the non-impregnated portion ratio is 25% or more, in order to reduce voids during vacuum pressing. On the other hand, when the maximum value of the unimpregnated portion ratio is 60% or less, peeling at the unimpregnated portion can be suppressed, and the shape stability of the prepreg can be improved, which is preferable.

In addition, since the matrix resin is not attached to the dry reinforcing fiber, the cross-sectional shape of the reinforcing fiber is easily observed clearly in the prepreg cross-sectional photograph.On the other hand, if the matrix resin is attached to the reinforcing fiber, the fiber cross-sectional shape is reversed. It is easy to be unclear. Further, if the matrix resin is not attached to the reinforcing fibers, the reinforcing fibers are easily peeled off from each other and often form voids.

Hereinafter, examples of the prepreg of the present invention will be described in more detail with reference to the drawings.

FIGS. 1 and 2 show examples of cross-sectional photographs (SEM) of the multilayer prepreg of the present invention. In the cross-sectional photograph, a reference line was drawn on the upper surface of the prepreg, and a horizontal auxiliary line was drawn every 10 μm below the prepreg, to determine the unimpregnated portion ratio (the horizontal auxiliary line is omitted in FIGS. 1 and 2). And the boundary which separates an impregnated layer and an unimpregnated layer between a horizontal auxiliary line with an unimpregnated portion ratio of less than 7% and a horizontal auxiliary line with an unimpregnated portion ratio of 7% or more is shown by a broken line. FIG. 1 is a typical example of the present invention. The first layer is an impregnated layer on the upper surface of the prepreg. The cross-sectional shape of the reinforcing fiber is unclear, and it can be seen that the matrix resin is impregnated. Although the first layer includes a small void (each cross-sectional area is about 70 μm ² ) having a side of about 10 μm, almost all of the layer is an impregnated part. In the second layer, which is an unimpregnated layer, it can be seen that the impregnated portions and the voids are alternately arranged in the horizontal direction. The maximum value of the unimpregnated portion ratio in the second layer is 45%. In the third layer, which is an impregnated layer, there are small voids (having a cross-sectional area of about 120 μm ² ) near the center, but almost all layers are impregnated. Further, the thickness of the third layer is 50 μm or more. In the fourth layer, which is an unimpregnated layer, it can be seen that the impregnated portions and the voids are alternately arranged in the horizontal direction. In addition, the maximum value of the unimpregnated portion ratio in the fourth layer is 30%. In the fifth layer (layer on the lower surface of the prepreg), which is an impregnated layer, there is a portion including a small void (cross-sectional area is about 170 μm ² ) on the right side, but almost all of the layers are impregnated portions.

FIG. 2 is an example of a multi-layer prepreg of the present invention different from FIG. The first layer is an impregnated layer on the prepreg upper surface, and it can be seen that the matrix resin is impregnated to such an extent that the cross-sectional shape of the reinforcing fiber cannot be confirmed. Almost all of the layers are impregnated parts. In the second layer, which is an unimpregnated layer, it can be seen that large voids and large dry reinforcing fiber aggregates are horizontally arranged in the impregnated portion. The portion where the dry reinforcing fibers are aggregated to form a large area is referred to as a dry reinforcing fiber aggregate. Further, the dry reinforcing fiber portion appears to be broken vertically. The maximum value of the unimpregnated portion ratio in the second layer is 49%. The third layer, which is an impregnated layer, includes two small voids on the left side (cross-sectional areas of about 310 μm ² and about 220 μm ² ), but almost all of the layers are impregnated parts. Further, the thickness of the third layer is 50 μm or more. In the fourth layer, which is an unimpregnated layer, it can be seen that there is a large dry reinforcing fiber aggregated portion in the center and that it is cracked vertically in it. In addition, the maximum value of the unimpregnated portion ratio in the fourth layer is 54%. In the fifth layer (layer on the lower surface of the prepreg), which is an impregnated layer, almost all of the layers are impregnated portions.

In the example of FIGS. 1 and 2, the second and fourth layers, which are the non-impregnated layers, include the impregnated portions together with the dry reinforcing fiber aggregates and the voids, thereby suppressing peeling and displacement at the non-impregnated portions. However, the shape stability of the entire prepreg can be improved. Further, even when the prepreg is formed into a roll shape, roll collapse can be significantly suppressed even when the prepreg is placed vertically. Specifically, the maximum value of the unimpregnated portion ratio is preferably 60% or less.

す る と Further, when the thickness of the impregnated layer in the prepreg inner layer is 30 μm or more, the shape stability of the entire prepreg can be further improved.

In the impregnated layer, it is preferable that the number of large voids or large dry reinforcing fiber aggregates in the cross section of the prepreg is zero because the shape stability of the entire prepreg can be improved. Here, the size of the large void or the large dry reinforcing fiber aggregate is 500 μm ² or more in cross-sectional area.

According to the present invention, the non-impregnated layer forms a degassing path during molding, and the generation of voids derived from volatile components contained in the matrix resin can be suppressed or prevented. This effect is very useful especially in vacuum pressing.

Although FIGS. 1 and 2 show an example of five layers of the impregnated layer / unimpregnated layer / impregnated layer / unimpregnated layer / impregnated layer, an arbitrary number of sets of unimpregnated layer / impregnated layer are added. Of course, a prepreg having a more multilayer structure can be used. In the case where the thickness of the entire prepreg is constant, when the number of layers is increased, the thickness of the unimpregnated portion is relatively reduced, so that the shape stability of the entire prepreg can be further improved.

Further, in the prior art, when partially impregnated prepregs are laminated, there is a problem that an air layer is easily sandwiched between the prepregs, which tends to remain as voids at the time of molding. Another advantage is that the possibility of sandwiching an air layer between the prepregs can be greatly reduced because the prepreg has already been laminated.

層 間 Further, in order to increase the toughness and impact resistance of FRP, prepregs can contain interlayer reinforcing particles as described in JP-A-1-104624 and the like. Since the interlayer reinforcing particles form a matrix resin layer between the reinforcing fiber layer and the reinforcing fiber layer, when this is applied to the present invention, it may be contained in the upper and lower impregnation layers of the multilayer prepreg. preferable. It is more preferable that the interlayer reinforcing particles are contained in the impregnated layer of the inner layer in addition to the upper and lower surfaces of the multilayer prepreg. That is, it is more preferable that two thin prepregs containing interlayer reinforcing particles are bonded to the impregnation layer.

で は In the above-described prepreg containing interlayer-reinforced particles, the case where two thin prepregs are bonded has been described as an example, but this may be a form in which three, four, or even more prepregs are bonded. Particularly, in the case of laminating a plurality of thin prepregs, the toughness and impact resistance of FRP can be further improved, which is preferable.

と Further, it is preferable that the arrangement of the reinforcing fibers in the planar direction is substantially the same in the prepreg, because the mechanical properties and the anisotropy of the FRP can be easily designed by the laminated structure of the prepreg. Here, that the arrangement of the reinforcing fibers in the planar direction is substantially the same in the prepreg means that when a unidirectional base material (UD base material) in which reinforcing fibers are aligned in one direction is used, Means that the reinforcing fibers are oriented in the 0 ° direction on the horizontal auxiliary line. In addition, when a normal woven fabric is used, it means that the number of reinforcing fibers in the 0 ° direction and the 90 ° direction is the same. When a bias substrate is used, it means that the number of reinforcing fibers in each bias direction is the same. These can be obtained by stacking a plurality of reinforcing fiber sheets of the same standard in the same direction to produce a multilayer prepreg.

Further, the multilayer structure prepreg with a release sheet of the present invention has a release sheet laminated on at least one surface of the multilayer structure prepreg, whereby the multilayer structure prepreg is conveyed, wound up in a roll shape, and unwound. It becomes possible.

マ ト リ ッ ク ス The matrix resin used in the multilayer prepreg according to the present invention can be appropriately selected depending on the application, but generally contains a thermoplastic resin or a thermosetting resin. The matrix resin may be a resin that is heated and melted or a resin that is liquid at room temperature. Further, a solution or a varnish formed using a solvent may be used.

As the matrix resin, a resin 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 liquids at room temperature, or may be used as solids or viscous liquids at room temperature to reduce the viscosity by heating, or may be used as a melt by melting, or a solvent. May be used as a solution or varnish.

The thermoplastic resin is selected from a carbon-carbon bond, an amide bond, an imide bond, an ester bond, an ether bond, a carbonate bond, a urethane bond, a urea bond, a thioether bond, a sulfone bond, an imidazole bond, and a 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), polybenzimidazole (PBI), polyimide (PI), polyetherimide (PEI), polysulfone (PSU), polyether sulfone (PES), polyether ketone (PEK), polyether ether ketone (PEEK), polyether ketone ketone (PEKK), polyaryl ether ketone (PAEK), polyamide imide (PAI), etc. it can. In fields requiring heat resistance such as aircraft applications, PPS, PES, PI, PEI, PSU, PEEK, PEKK, PEAK, and the like are suitable. On the other hand, for industrial applications and automotive applications, polyolefins such as polypropylene (PP), PA, polyester, PPS, and the like are preferable 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 may be used as a polymer blend alloy by mixing various types.

Examples of the thermosetting resin include an epoxy resin, a maleimide resin, a polyimide resin, a resin having an acetylene terminal, a resin having a vinyl terminal, a resin having an allyl terminal, a resin having a nadic acid terminal, and a resin having a cyanate ester terminal. Can be These can be generally used in combination with a curing agent or a curing catalyst. In addition, these thermosetting resins can be appropriately used in combination.

エ ポ キ シ As a thermosetting resin suitable for the present invention, an epoxy resin is preferably used because of its excellent heat resistance, chemical resistance, and mechanical properties. In particular, an epoxy resin using an amine, a phenol, or a compound having a carbon-carbon double bond as a precursor is preferable. Specifically, as an epoxy resin having an amine as a precursor, various isomers of tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, and triglycidylaminocresol, and phenols are used as precursors. Bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, phenol novolak type epoxy resin, cresol novolak type epoxy resin, a compound having a carbon-carbon double bond as a precursor Examples of the epoxy resin include, but are not limited to, alicyclic epoxy resins. Brominated epoxy resins obtained by brominating these epoxy resins are also used. An epoxy resin having an aromatic amine represented by tetraglycidyldiaminodiphenylmethane as a precursor has a good heat resistance and a good adhesion to a reinforcing fiber, and is most suitable for the present invention.

Thermosetting resin is preferably used in combination with a curing agent. For example, in the case of an epoxy resin, the curing agent may be a compound having an active group capable of reacting with an epoxy group. Preferably, a compound having an amino group, an acid anhydride group, or an azide group is suitable. Specifically, dicyandiamide, various isomers of diaminodiphenylsulfone, and aminobenzoic acid esters are suitable. More specifically, dicyandiamide is preferably used because of its excellent prepreg preservability. Further, various isomers of diaminodiphenyl sulfone are most suitable for the present invention because they give cured products having good heat resistance. As the aminobenzoic acid esters, trimethylene glycol di-p-aminobenzoate and neopentyl glycol di-p-aminobenzoate are preferably used. Although the heat resistance is lower than that of diaminodiphenyl sulfone, the tensile strength is lower. Because it is excellent, it is selected and used according to the application. It is also possible to use a curing catalyst if necessary. From the viewpoint of improving the pot life of the coating liquid, it is also possible to use a complexing agent capable of forming a complex with a curing agent or a curing catalyst.

In the present invention, it is also preferable to use a thermoplastic resin mixed with a thermosetting resin. A mixture of a thermosetting resin and a thermoplastic resin gives better results than using the thermosetting resin alone. This is because the thermosetting resin is generally capable of low pressure molding by an autoclave while having a brittle defect, whereas the thermoplastic resin is generally difficult to perform low pressure molding by an autoclave while having the advantage of being tough. This is because they exhibit a trade-off characteristic, that is, they can be used in combination to balance physical properties and moldability. When mixed and used, it is preferable to contain the thermosetting resin in an amount of more than 50% by mass from the viewpoint of the mechanical properties of the FRP obtained by curing the prepreg.

According to the present invention, the matrix resin may contain inorganic particles or organic particles. Although the inorganic particles are not particularly limited, for example, carbon-based particles, boron nitride particles, titanium dioxide particles, silicon dioxide particles, and the like can be suitably used to impart conductivity, heat conductivity, thixotropy, and the like. Although the organic particles are not particularly limited, the use of polymer particles is particularly preferable because the toughness, impact resistance, and vibration damping properties of the obtained FRP can be improved.

プ リ Further, the prepreg of the present invention can contain polymer particles such as the above-mentioned interlayer reinforcing particles, and the polymer particles are generally contained in a matrix resin. At this time, it is preferable that the glass transition temperature (Tg) or the melting point (Tm) of the polymer particles be higher than the coating liquid temperature by 20 ° C. or more, because the shape of the polymer particles can be easily maintained in the matrix resin. The Tg of the polymer particles can be measured using a temperature-modulated DSC under the following conditions. As the temperature modulation DSC device, TA Q Instruments # Q1000 or the like is suitable, and it can be used after being calibrated with high-purity indium in a nitrogen atmosphere. The measurement conditions are as follows: the temperature rise rate is 2 ° C./min, and the temperature modulation condition is a cycle of 60 seconds and an amplitude of 1 ° C. The reversible component is separated from the total heat flow obtained in this way, and the temperature at the middle point of the step signal can be set to Tg.

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

Further, it is preferable that the polymer particles do not dissolve in the matrix resin. As such polymer particles, for example, appropriate ones can be used with reference to the description in WO2009 / 142231 pamphlet and the like. More specifically, polyamide or polyimide can be preferably used, and polyamide, which can greatly improve impact resistance due to excellent toughness, is most preferable. Polyamides such as polyamide 12, polyamide 11, polyamide 6, polyamide 66, polyamide 6/12 copolymer, and the epoxy compound described in Example 1 of JP-A-01-104624 are semi-IPN (polymer interpenetrating network structure). Polyamide (semi-IPN polyamide) or the like can be suitably used. The shape of the thermoplastic resin particles may be a spherical particle, a non-spherical particle, or a porous particle, but a spherical shape is particularly preferable in the production method of the present invention since the flow characteristics of the resin are not deteriorated. Further, a spherical shape is a preferable embodiment in that there is no starting point of stress concentration and high impact resistance is given.

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

In order to increase the toughness of the CFRP interlayer resin layer, it is preferable to keep the polymer particles in the 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 still more preferably in the range of 10 to 30 μm. By setting the number average particle diameter to 5 μm or more, the particles do not enter the bundle of the reinforcing fibers and can stay in the 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 prepreg surface can be optimized, and thus, in the obtained CFRP, the fiber mass content can be optimized.

に お い て In the multilayer prepreg of the present invention, the degree of impregnation of the matrix resin is desirably high as long as the vacuum pressure formability is not impaired. The state of the impregnation of the matrix resin can be checked for the presence or absence of impregnation by tearing the collected multi-layered prepreg and visually observing the inner layer part, but can be more quantitatively evaluated by, for example, a peeling method. . The impregnation rate of the coating liquid by the peeling method can be measured as follows. That is, the collected multi-layered prepreg is sandwiched between adhesive tapes, and the adhesive tape is peeled off to separate the reinforcing fibers to which the matrix resin has adhered from the reinforcing fibers to which the matrix resin has not adhered. Then, the ratio of the mass of the reinforcing fibers to which the matrix resin has adhered to the mass of the entire reinforcing fiber sheet put in can be taken as the impregnation rate of the matrix resin by the peeling method. Further, the degree of impregnation can be evaluated from the water absorption of the prepreg by utilizing the capillary phenomenon, and the lower the water absorption, the higher the impregnation. More specifically, the method described in Japanese Patent Application Publication No. 2016-510077 can be applied.

In the present invention, the width of the multilayer prepreg is not particularly limited, and may be a wide width of about several tens cm to 2 m or a tape having a width of several mm to several tens mm. can do. In recent years, in order to increase the efficiency of the prepreg laminating process, devices called ATL (Automated Tape Laying) and AFP (Automated Fiber Placement) for automatically laminating narrow prepregs and prepreg tapes have been widely used. Therefore, it is also preferable that the width is adjusted to this. ATL often uses narrow prepregs having a width of about 7.5 cm, about 15 cm, or about 30 cm. AFP often uses prepreg tapes having a width of about 3 mm to about 25 mm. For this reason, in the present invention, when prepreg tape is used, the width is preferably 30 mm or less.

が As described above, the prepreg of the present invention has been described. Next, a specific manufacturing method for obtaining the prepreg of the present invention will be specifically described with examples. A method for efficiently obtaining a prepreg having a multilayer structure according to the present invention has not been known. Then, in order to obtain the prepreg of the present invention, an unprecedented manufacturing method is used. Note that the present invention is not construed as being limited to the specific examples described below.

Specifically, the matrix resin is stored, and a liquid pool portion having a portion whose cross-sectional area is continuously reduced vertically downward, and a narrowed portion having a slit-shaped outlet communicating with a lower end of the liquid pool portion, A method for producing a prepreg in which a reinforcing fiber sheet is passed vertically downward to impart a matrix resin to the reinforcing fiber sheet, wherein a plurality of reinforcing fiber sheets are formed in the liquid reservoir in a thickness direction thereof. A method for producing a prepreg, comprising a step of charging at intervals and a step of uniting the plurality of reinforcing fiber sheets inside the application section after the introduction.

As a prepreg manufacturing method using a plurality of reinforcing fiber sheets, for example, JP-A-2012-167230 discloses a method in which a resin is applied to one side of a reinforcing fiber sheet, and then another reinforcing fiber sheet is laminated and impregnated. A method for producing a prepreg is described. In this manufacturing method, a resin is disposed in the inner layer in advance so that an unimpregnated portion is not formed even in a thick prepreg, and an object is to obtain a prepreg having no unimpregnated portion. For this reason, the technical idea is completely different from the method for obtaining the prepreg of the present invention described above. Moreover, even if the impregnation degree is intentionally reduced in the method described in JP-A-2012-167230, the prepreg of the present invention cannot be obtained because the upper and lower surfaces of the prepreg become unimpregnated layers.

Hereinafter, a manufacturing method for obtaining the multilayer prepreg of the present invention will be described in detail with reference to FIG. FIG. 3 shows a case where the reinforcing fiber sheet is a UD base material. After arranging the plurality of reinforcing fibers 1 unwound from the creel 11 in one direction (the depth direction of the paper) by the arrangement device 12 to obtain the reinforcing fiber sheet 2, the reinforcing fiber sheet 2 is substantially applied to the application unit 20. , And the incident angle and the position on the matrix resin 4 are adjusted by the holding guide 14, and then guided to the coating unit 20. Thereafter, the matrix resin 4 is applied to both surfaces of the reinforcing fiber sheet 2 in the application section 20, and the matrix resin 4 is applied to both surfaces of each reinforcing fiber sheet 2 and partially impregnated prepreg partially impregnated. Is formed. Then, the operation of combining the plurality of partially impregnated prepregs into a single sheet near the stenotic portion in the application section 20, that is, overlapping the reinforcing fiber sheets so as to be integrated when the prepreg is led out from the stenotic portion is performed. By doing so, a multilayer prepreg 3 can be obtained. FIG. 3 illustrates the case where the number of reinforcing fiber sheets is two, but the number of reinforcing fiber sheets and the type of each reinforcing fiber sheet can be changed as needed. Here, passing substantially in the vertical direction Z means that the angle α between the Z direction (vertical line) and the running direction of the reinforcing fiber sheet is within 20 °.

At this time, on the upper end liquid level of the liquid reservoir 22, the narrowest distance Ln (see FIG. 4) among the distance between the wall surface (that is, the wall member) of the liquid reservoir and the reinforcing fiber sheet 2 and the distance between the plurality of reinforcing fiber sheets 2 is shown. 5, the relationship between the wall member 21a and the reinforcing fiber sheet 2) and the widest distance Lb (in FIG. 5, the distance between the reinforcing fiber sheets 2) are 1 ≦ Lb / Ln ≦ 3. It is preferable to satisfy the following. This is because, when the matrix resin 4 is applied by running the reinforcing fiber sheet 2, the matrix resin 4 is consumed and the upper end liquid level of the liquid reservoir 22 gradually decreases. If the ratio is too large, the upper end liquid level lowering speed of each region of the liquid reservoir 22 divided by the reinforcing fiber sheet 2 is different, and the upper end liquid surface of each region of the liquid reservoir 22 divided by the reinforcing fiber sheet 2 A height difference occurs. When the liquid level difference between the front and back of the reinforcing fiber sheet 2 becomes large, the matrix resin 4 tries to flow from the higher liquid surface to the lower liquid surface, and the reinforcing fiber sheet 2 is deformed in the thickness direction and contacts the wall member 21. When the UD base material is used as the reinforcing fiber sheet 2, there is a concern that the matrix resin 4 flows into the space between the reinforcing fibers and breaks the arrangement of the reinforcing fibers.

For example, when the ratio of Lb / Ln is too large in FIG. 5, the liquid level in the region (left and right regions) sandwiched between the wall member 21 and the reinforcing fiber sheet 2 during traveling of the reinforcing fiber sheet 2 rapidly decreases, and When the matrix resin 4 is about to flow from the region (center region) sandwiched between the reinforcing fiber sheets 2, the reinforcing fiber sheet 2 is pressed against the wall member 21. At this time, a large amount of fluff is generated due to the friction between the reinforcing fiber sheet 2 and the wall member 21, and in the worst case, the reinforcing fiber sheet 2 cannot run.

Conversely, in FIG. 5, when the interval between the plurality of reinforcing fiber sheets 2 at the upper end liquid level of the liquid reservoir 22 is too small, the liquid level in the region (center region) sandwiched between the plurality of reinforcing fiber sheets 2 sharply increases. When the matrix resin 4 is depleted and the matrix resin 4 is depleted, the matrix resin 4 tends to flow into the central region, and the running of the reinforcing fiber sheet 2 may also become unstable.

From the above, from the viewpoint of stabilizing the running of the reinforcing fiber sheet 2, in order to make the height of the liquid surface at the upper end of the liquid reservoir 22 uniform over the entire area, the distance between the wall surface of the liquid reservoir and the reinforcing fiber sheet 2 is set. It is preferable to make the ratio of the spacing between the plurality of reinforcing fiber sheets 2 close to 1. Specifically, the relationship between the narrowest interval Ln and the widest interval Lb preferably satisfies 1 ≦ Lb / Ln ≦ 3.

Here, in the application section 20 shown in FIG. 5, the interval between the wall member 21 and the reinforcing fiber sheet 2 at the upper end liquid level of the liquid reservoir 22 is narrower than the interval between the plurality of reinforcing fiber sheets. This is not true if the relational expression is satisfied. For example, the interval between the plurality of reinforcing fiber sheets 2 may be somewhat wider.

(4) Further, the release sheet 5a is unwound from the release sheet supply device 16a, the release sheet 5a is laminated on one surface of the multilayer prepreg 3, and is wound up in a roll shape by the winding device 17 via the take-off roll 15. In particular, even when the matrix resin 4 applied to the multilayer prepreg 3 reaches the take-off roll 15, a part or all of the matrix resin 4 is present on the surface of the multilayer prepreg 3 and has high fluidity and adhesiveness. The release sheet 5 a can prevent a part of the matrix resin 4 on the surface of the multilayer prepreg 3 from being transferred to the take-off roll 15. Furthermore, adhesion between the multilayer prepregs 3 can be prevented, and handling in a later step is facilitated. The release sheet is not particularly limited as long as it has the above-mentioned effect, and examples thereof include release paper, and those obtained by applying a release agent to the surface of an organic polymer film. If necessary, a release sheet 5b may be further laminated on another surface of the multilayer prepreg 3. The release sheets 5a and 5b may be of the same type or different types depending on the purpose.

The same process can be adopted after forming the reinforcing fiber sheet 2 in FIG. 3 even when the reinforcing fiber sheet is a reinforcing fiber fabric. When using a reinforcing fiber fabric, the creel portion may be a reinforcing fiber fabric unwinding device.

FIG. 4 shows another preferred embodiment of the present production method. The reinforcing fibers 414 are pulled out from the reinforcing fiber bobbin 412 hung on the creel 411, and the reinforcing fiber sheet 416 is formed by the reinforcing fiber arrangement device 415 via the direction changing guide 413. Although FIG. 4 shows two sets of this process, three or more sets may be used. In addition, three reinforcing fiber bobbins in one set are described, but actually, the required number of bobbins according to the purpose is multiplied. The plurality of reinforcing fiber sheets 416 are guided upward via the direction change rolls 419, and then conveyed vertically downward via the direction change rolls 419, and are preheated by the preheating device 420 to a temperature equal to or higher than the matrix resin temperature in the application section. You. Then, the angle and position of incidence on the matrix resin are adjusted by the holding guide 412, and the guide is guided to the application unit 430. Thereafter, the matrix resin is applied and impregnated in the application section 430, respectively, and united near the outlet in the application section 430 to form a multilayer prepreg 471. The multilayer prepreg 471 is stacked on the direction change roll 441 with the release sheet 446 unwound from the release sheet (upper) supply device 442, and is taken up by the high tension take-off S-shaped roll 449 which is a high tension take-off device. Can be At the same time, the release sheet unwound from the release sheet (lower) supply device 443 is laminated on the high tension take-off S-shaped roll 449, and the release sheets are arranged on both upper and lower surfaces of the multilayer prepreg. Then, this is supplied to the replenishment new apparatus 450 and preheated by the hot plate 451, and then impregnation is advanced using the heating nip roll 452. Then, after being cooled by the cooling device 461, the release sheet on the upper side is peeled off via the take-off device 462, and the multilayer prepreg / release sheet is wound up in a roll shape by the winder 464. The upper release sheet is taken up by a release sheet (upper) take-up device 463.

Hereinafter, detailed preferred embodiments of the present production method will be further described.

<Formation of UD base material>
When a UD base material is used as the reinforcing fiber sheet, a known method can be used for forming the reinforcing fiber sheet. There is no particular limitation, but a reinforcing fiber bundle in which single fibers are arranged in advance is formed, and the reinforcing fiber bundle is formed. It is preferable to form a UD base material by further arranging the fiber bundles from the viewpoint of process efficiency and uniform arrangement. For example, in the case of carbon fibers, a tow, which is a tape-like reinforcing fiber bundle, is wound around a bobbin, and a reinforcing fiber sheet can be obtained by arranging the tape-like reinforcing fiber bundles drawn out from the bobbin. Also, a reinforcing fiber arrangement mechanism for neatly arranging reinforcing fiber bundles drawn from creeled bobbins, eliminating undesirable overlapping and folding of reinforcing fiber bundles in sheet-like reinforcing fiber bundles, and gaps between reinforcing fiber bundles. It is preferable to have As the reinforcing fiber arranging mechanism, a known roller or comb-type arranging device can be used. It is also useful to stack a plurality of sheet-shaped reinforcing fiber bundles arranged in advance from the viewpoint of reducing the gap between the reinforcing fibers. The creel is preferably provided with a tension control mechanism when drawing out the reinforcing fibers. As the tension control mechanism, a known mechanism can be used, and a brake mechanism or the like can be used. The tension can also be controlled by adjusting the thread guide.

<Smoothing of reinforcing fiber sheet>
In the above-mentioned manufacturing method, the uniformity of the application amount of the matrix resin at the application portion can be improved by increasing the surface smoothness of the reinforcing fiber sheet. For this reason, it is preferable to guide the reinforcing fiber sheet to the application section after performing a smoothing treatment. The method of smoothing is not particularly limited, and examples thereof include a method of physically pressing with a facing roll or the like, and a method of moving a reinforcing fiber using an air flow. The physical pressing method is preferred because it is simple and does not easily disturb the arrangement of the reinforcing fibers. More specifically, calendering or the like can be used. The method using an air flow is preferable because it not only causes less abrasion but also has the effect of widening the reinforcing fiber sheet. The smoothing device can be installed, for example, between the reinforcing fiber arrangement device 415 and the preheating device 420 in FIG.

<Wide width of reinforced fiber sheet>
In addition, in the above-mentioned manufacturing method, it is also preferable to guide the reinforcing fiber sheet to the liquid pool after widening the reinforcing fiber sheet from the viewpoint of efficiently manufacturing the thin-layer prepreg. Further, by making the thin-layer prepreg into multiple layers, the layer thickness of the multilayer prepreg can be reduced, and the toughness and impact resistance of the FRP can be improved. There is no particular limitation on the widening processing method, 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, there is a method of bringing a sheet-like reinforcing fiber bundle into contact with a vibrating roll as described in, for example, JP-A-2015-22799. As the vibration direction, when the traveling direction of the sheet-like reinforcing fiber bundle is the X axis, it is preferable to apply vibrations in the Y axis direction (horizontal direction) and the Z axis direction (vertical direction). It is also preferable to use a combination of rolls. It is preferable that a plurality of projections are provided on the surface of the vibrating roll, because the abrasion of the reinforcing fibers by the roll can be suppressed. As a method using an air flow, see, for example, SEN-I GAKKAISHI, vol. 64, P-262-267 (2008). The described method can be used. The widening device can be installed, for example, between the reinforcing fiber arrangement device 415 and the preheating device 420 in FIG.

<Preheating of reinforced fiber sheet>
In addition, in the present invention, it is preferable that the reinforcing fiber sheet is heated and then guided to the liquid pool portion, because the temperature decrease of the matrix resin can be suppressed and the viscosity uniformity of the coating liquid can be improved. The reinforcing fiber sheet is preferably heated to a temperature close to the matrix resin temperature in the liquid pool. Heating means for this purpose include air heating, infrared heating, far infrared heating, laser heating, contact heating, and heating medium heating ( Various means such as steam can be used. Above all, infrared heating is preferable because the apparatus is simple and the sheet-like reinforcing fiber bundle sheet can be directly heated, so that it can be efficiently heated to a desired temperature even at a high running speed.

<Matrix resin viscosity>
As the matrix resin used in the present invention, it is preferable to select an optimum viscosity from the viewpoint of processability and stability. Specifically, when the viscosity is in the range of 1 to 60 Pa · s, the dripping at the constricted portion exit can be suppressed, and the high-speed running property and the stable running property of the reinforcing fiber sheet can be improved, which is preferable. Here, the viscosity is measured at a strain rate of 3.14 s ^-1 at the temperature of the coating liquid in the liquid pool. <Coating Step>
Next, a process of applying a matrix resin to the reinforcing fiber sheet will be described in detail with reference to FIGS. Here, a UD base material is shown as an example of the reinforcing fiber sheet 2. FIG. 5 is an enlarged detailed cross-sectional view of the application section 20 in FIG. The coating unit 20 includes wall members 21a and 21b opposed to each other with a predetermined gap D therebetween. Between the wall members 21a and 21b, a liquid pool part 22 having a cross-sectional area continuously decreasing in a vertical downward Z direction is provided. , A slit-shaped constricted portion located below the liquid reservoir 22 (on the side where the reinforcing fiber sheet 2 is carried out) and having a smaller cross-sectional area than the upper surface of the liquid reservoir 22 (on the side where the reinforcing fiber sheet 2 is introduced). 23 are formed. In FIG. 5, the reinforcing fiber sheet 2 is described assuming a UD base material, but the reinforcing fibers are arranged in the depth direction of the paper surface.

(4) In the application section 20, the reinforcing fiber sheet 2 introduced into the liquid pool section 22 travels downward with the surrounding matrix resin 4 accompanying it. At this time, since the cross-sectional area of the liquid reservoir 22 decreases in the vertical direction Z, the accompanying matrix resin 4 is gradually compressed, and the pressure of the matrix resin 4 increases toward the lower part of the liquid reservoir 22. . When the pressure in the lower part of the liquid reservoir 22 becomes higher, the accompanying liquid flow becomes more difficult to flow further downward, flows in the direction of the wall members 21a and 21b, and is then blocked by the wall members 21a and 21b and flows upward. Become like As a result, a circulating flow T is formed in the liquid reservoir 22 along the outer flat surface of the reinforcing fiber sheet 2 and the wall surfaces of the wall members 21a and 21b. As a result, even if the reinforcing fiber sheet 2 brings the fluff into the liquid reservoir 22, the fluff moves along the circulating flow T and cannot approach the lower part of the liquid reservoir 22 or the narrowed portion 23 where the hydraulic pressure is large. Further, as described below, the air bubbles adhere to the fluff, and the fluff moves upward from the circulating flow T and passes near the upper liquid level of the liquid reservoir 22. Therefore, not only is it possible to prevent the fluff from clogging the lower portion of the liquid reservoir 22 and the narrowed portion 23, but also it is possible to easily collect the retained fluff from the upper liquid surface of the liquid reservoir 22. Furthermore, when the reinforcing fiber sheet 2 is run at a high speed, the above-mentioned liquid pressure is further increased, so that the effect of eliminating fluff becomes higher. As a result, it becomes possible to apply the matrix resin 4 to the reinforcing fiber sheet 2 at a high speed, and the productivity is greatly improved.

{Circle around (4)} The increased liquid pressure has the effect that the matrix resin 4 easily impregnates the inner layer of the reinforcing fiber sheet 2. This is based on the property (Darcy's law) that when a coating liquid is impregnated into a porous body such as a reinforcing fiber bundle, the degree of impregnation increases with the pressure of the coating liquid. Also in this case, when the reinforcing fiber sheet 2 is run at a higher speed, the hydraulic pressure is further increased, so that the impregnation effect can be further enhanced. The matrix resin 4 is impregnated with air / liquid replacement with air bubbles remaining in the inner layer of the reinforcing fiber sheet 2, but the air bubbles pass through the gaps in the inner layer of the reinforcing fiber sheet 2 due to the above-mentioned liquid pressure and buoyancy. The fibers are discharged in the fiber orientation direction (vertically upward). At this time, since the bubbles are discharged without pushing the matrix resin 4 impregnated, there is also an effect of not impairing the impregnation. Further, some of the bubbles are discharged into the liquid from the surface of the reinforcing fiber sheet 2, but these bubbles are also quickly eliminated upward in the vertical direction by the above-mentioned liquid pressure and buoyancy. There is also an effect that the discharge of air bubbles proceeds efficiently without staying at the lower part of the lower part 22. With these effects, it is possible to impregnate the reinforcing fiber sheet 2 with the matrix resin 4 efficiently. The impregnation degree is governed by the liquid pressure of the matrix resin 4 and the pressurization time in the application section 20 as described by Darcy's law. (2) The shape of the application section 20 can be designed, and the viscosity of the matrix resin can be adjusted. Then, since a plurality of prepregs that leave unimpregnated portions are united in the application portion 20, it is possible to obtain the multilayer prepreg of the present invention.

According to the manufacturing method of the present invention, not only the above-mentioned prepreg having a multilayer structure can be obtained, but also a prepreg having a high degree of impregnation can be obtained depending on the condition setting. It is described below. In the application section 20 shown in FIG. 5, the plurality of reinforcing fiber sheets 2 are introduced into the liquid storage section 22 at intervals in the thickness direction, and then united and taken up inside the application section 20, thereby obtaining the liquid storage section 22. In the lower portion and the constricted portion 23, the impregnation of the matrix resin 4 proceeds in each of the supplied reinforcing fiber sheets 2. Thereby, in the application section 20 of FIG. 5, the prepreg 3 having a higher degree of impregnation of the matrix resin 4 can be obtained as compared with the case where the reinforcing fiber sheet 2 is put into the liquid pool section 22 in a state of being overlapped from the beginning. Becomes possible. Here, in the application section 20 in FIG. 5, two reinforcing fiber sheets 2 are introduced into the liquid pool section 22 at intervals in the thickness direction, but three or more sheets may be provided. When a prepreg 3 having a constant thickness is obtained, as the number of reinforcing fiber sheets 2 introduced into the liquid reservoir 22 increases, the thickness of each of the reinforcing fiber sheets supplied decreases, and the necessary impregnation distance decreases. Thus, the degree of impregnation of the matrix resin 4 can be further increased. At this time, since the thickness of each reinforcing fiber sheet 2 becomes thinner as the number of reinforcing fiber sheets 2 increases, the widening of the reinforcing fiber sheet 2 is performed using the widening device as described above, and the desired width is obtained. After that, the prepreg 3 having a uniform thickness is preferably charged into the liquid reservoir 22.

Further, the layered prepreg 3 in which the plurality of reinforcing fiber sheets 2 are united is automatically centered at the center of the gap D by the above-mentioned increased hydraulic pressure, and the reinforcing fiber sheet 2 and / or the layered prepreg 3 are liquidized. There is also an effect of preventing the generation of fluff here without directly rubbing against the wall surface of the pool portion 22 or the narrowed portion 23. This is because when the reinforcing fiber sheet 2 and / or the layered prepreg 3 approach one of the gaps D due to a disturbance or the like, the matrix resin 4 is pushed into the narrower gap on the approaching side and is compressed, so that the approach is made. This is because the hydraulic pressure further increases on the side and pushes the reinforcing fiber sheet 2 and / or the layered prepreg 32 back to the center of the gap D.

The constriction 23 is designed to have a smaller cross-sectional area than the upper surface of the liquid reservoir 22. As understood from FIG. 5 and FIG. 7, the length of the pseudo plane formed by the reinforcing fiber sheet 2 in the perpendicular direction is small, that is, the interval between the members is small, so that the cross-sectional area is reduced. This is because the impregnation and the self-centering effect can be obtained by increasing the fluid pressure at the constricted portion as described above. The cross-sectional shape of the uppermost surface of the constricted portion 23 should be made to match the cross-sectional shape of the lowermost surface of the liquid reservoir 22, from the viewpoint of the running property of the reinforcing fiber sheet 2 and the flow control of the matrix resin 4. Although preferred, the constriction 23 may be slightly larger if necessary.

Further, the total amount of the matrix resin 4 applied to the reinforcing fiber sheet 2 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 4 applied to the reinforcing fiber sheet 2 (to increase the basis weight). In this case, the wall members 21a and 21b may be installed so that the gap D is widened.

FIG. 6 is a bottom view of the application section 20 viewed from the direction of A in FIG. The application section 20 is provided with side wall members 24a and 24b for preventing the matrix resin 4 from leaking from both ends of the reinforcing fiber sheet 2 in the reinforcing fiber arrangement direction. The wall members 21a and 21b and the side wall members 24a and 24b are provided. An outlet 25 of the constriction 23 is formed in the enclosed space. Here, the outlet 25 has a slit shape, and the sectional aspect ratio (Y / D in FIG. 6) may be set according to the shape of the reinforcing fiber sheet 2 to which the matrix resin 4 is to be applied.

FIG. 7 is a cross-sectional view illustrating the structure of the inner layer portion of the application section when the application section 20 is viewed from the direction B. In addition, the wall member 21b is omitted in order to make the drawing easy to see, and the reinforcing fiber sheet 2 draws the reinforcing fibers so as to be arranged with a gap therebetween. The arrangement is preferable from the viewpoint of the quality of the multilayer prepreg 3 and the mechanical properties of the FRP.

FIG. 8 shows the flow of the coating liquid 2 in the gap 26. If the gap 26 is large, a vortex flows in the matrix resin in the direction of R. This vortex flow R becomes a flow (Ra) directed outward at a lower portion of the liquid pool portion 22, and thus tears the reinforcing fiber sheet 2 (when the reinforcing fiber sheet 2 is a UD base material, cracks in the reinforcing fiber bundle may occur. Occurs) or the spacing between the reinforcing fibers is widened, which may result in uneven arrangement of the reinforcing fibers when the prepreg 3 has a multilayer structure. On the other hand, at the upper part of the liquid reservoir 22, since the flow becomes inward (Rb), the reinforcing fiber sheet 2 is compressed in the width direction, and the end may be broken. In an apparatus such as that described in Patent Document 2 (Japanese Patent No. 3252278) for applying a coating liquid to both sides of a film, even if such a vortex flow in the gap 26 occurs, there is little influence on the quality. Had not been.

Therefore, in the present invention, it is preferable to restrict the width of the gap 26 so as to suppress the generation of the vortex at the end. Specifically, the width L of the liquid reservoir 22, that is, the interval L between the side plate members 24a and 24b is configured to satisfy the following relationship with the width W of the sheet-like reinforcing fiber bundle measured immediately below the narrowed portion 23. Is preferred.
L ≦ W + 10 (mm).

Thereby, generation of a vortex at the end is suppressed, cracking and end breakage of the reinforcing fiber sheet 2 can be suppressed, and the reinforcing fibers are uniformly arranged over the entire width (W) of the multilayer prepreg 3. A highly stable multilayer prepreg 3 can be obtained. As a result, not only the quality and quality of the prepreg can be improved, but also the mechanical properties and quality of the FRP obtained using the prepreg can be improved. More preferably, when the relationship between L and W is L ≦ W + 2 (mm), it is possible to further suppress cracks and end breaks of the reinforcing fiber sheet.

Further, it is preferable to adjust the lower limit of L to be not less than W-5 (mm) from the viewpoint of improving the uniformity of the dimension in the width direction of the multilayer prepreg 3.

In addition, it is preferable that the width regulation is performed at least at the lower part of the liquid reservoir 22 (the position G in FIG. 7) from the viewpoint of suppressing the generation of the vortex R due to the high liquid pressure below the liquid reservoir 22. Further, more preferably, when this width regulation is performed in the entire area of the liquid pool 22, the generation of the vortex flow R can be almost completely suppressed, and as a result, cracks and end breaks of the sheet-like reinforcing fiber bundle can be prevented. It can be almost completely suppressed.

In addition, from the viewpoint of suppressing the vortex flow in the gap 26, the width regulation may be performed only on the liquid pool 22. However, when the constriction 23 is similarly performed, the excess matrix resin 4 is applied to the side surface of the multilayer prepreg 3. It is preferable from the viewpoint of suppressing the occurrence of the above.

<Space between reinforcing fiber sheets>
FIG. 15 is a detailed cross-sectional view of the application unit 20 similar to FIG. In the application section 20 in FIG. 15, a plurality of reinforcing fiber sheets 2 are put into the liquid pool section 22 at intervals in the thickness direction. The incident angle and position of the reinforcing fiber sheet 2 are adjusted by the holding guide 14. At this time, on the upper end liquid level of the liquid reservoir 22, the narrowest distance Ln (of the distance between the wall surface of the liquid reservoir (that is, the wall member 21) and the reinforcing fiber sheet 2 and the distance between the plurality of reinforcing fiber sheets 2). In the case of FIG. 15, the relationship between the wall member 21 and the reinforcing fiber sheet 2) and the widest distance Lb (the distance between the plurality of reinforcing fiber sheets 2 in FIG. 15) satisfy 1 ≦ Lb / Ln ≦ 3. Preferably, it is satisfied. This is because, when the matrix resin 4 is applied by running the reinforcing fiber sheet 2, the matrix resin 4 is consumed and the upper end liquid level of the liquid reservoir 22 gradually decreases. If the ratio is too large, the upper end liquid level lowering speed of each region of the liquid reservoir 22 divided by the reinforcing fiber sheet 2 is different, and the upper end liquid surface of each region of the liquid reservoir 22 divided by the reinforcing fiber sheet 2 A height difference occurs. When the liquid level difference between the front and back of the reinforcing fiber sheet 2 becomes large, the matrix resin 4 tries to flow from the higher liquid surface to the lower liquid surface, and the reinforcing fiber sheet 2 is deformed in the thickness direction and contacts the wall member 21. When the UD base material is used as the reinforcing fiber sheet 2, there is a concern that the matrix resin 4 flows into the gaps between the reinforcing fibers and disturbs the arrangement of the reinforcing fibers.

For example, when the ratio of Lb / Ln is too large in FIG. 15, the liquid level in the region (left and right regions) sandwiched between the wall member 21 and the reinforcing fiber sheet 2 during traveling of the reinforcing fiber sheet 2 rapidly decreases, and When the matrix resin 4 is about to flow from the region (center region) sandwiched between the reinforcing fiber sheets 2, the reinforcing fiber sheet 2 is pressed against the wall member 21. At this time, a large amount of fluff is generated due to the friction between the reinforcing fiber sheet 2 and the wall member 21, and in the worst case, the reinforcing fiber sheet 2 cannot run.

Conversely, in FIG. 15, when the interval between the plurality of reinforcing fiber sheets 2 at the upper end liquid level of the liquid reservoir 22 is too narrow, the liquid level in the region (center region) sandwiched between the plurality of reinforcing fiber sheets 2 sharply increases. When the matrix resin 4 is depleted and the matrix resin 4 is depleted, the matrix resin 4 provided in the gaps between the plurality of reinforcing fiber sheets 2 becomes insufficient, and impregnation from the inside of the reinforcing fiber sheet 2 in the application section 20 does not sufficiently proceed, and the prepreg 3 may be impregnated poorly.

From the above, in order to stabilize the running of the reinforcing fiber sheet 2 and to improve the degree of impregnation of the prepreg 3 with the matrix resin, the liquid level in the upper end of the liquid reservoir 22 is made uniform over the entire area. It is preferable that the ratio of the space between the wall surface of the reservoir and the reinforcing fiber sheet 2 and the space between the plurality of reinforcing fiber sheets 2 is close to 1. Specifically, the relationship between the narrowest interval Ln and the widest interval Lb preferably satisfies 1 ≦ Lb / Ln ≦ 3.

Here, in the application section 20 shown in FIG. 15, the interval between the wall member 21 and the reinforcing fiber sheet 2 at the upper end liquid level of the liquid reservoir 22 is smaller than the interval between the plurality of reinforcing fiber sheets. This is not the case if the dimensional relationship is satisfied. For example, the interval between the plurality of reinforcing fiber sheets 2 may be wider.

<Union of reinforced fiber sheet>
In the application section 20 of FIG. 15, an example is shown in which the plurality of reinforcing fiber sheets 2 are united near the boundary between the liquid pool section 22 and the constricted section 23. May be performed anywhere within the coating unit 20. For example, a submerged guide 18 may be provided inside the liquid reservoir 22 and a plurality of reinforcing fiber sheets 2 may be joined in the middle of the liquid reservoir 22, as in the application section 20a in FIG. However, when the coalescence of the reinforcing fiber sheets 2 is performed near the upper end liquid level of the liquid reservoir 22, the amount of the matrix resin 4 in the region sandwiched between the plurality of reinforcing fiber sheets 2 is small. As described above, there is a concern that the matrix resin 4 provided in the gaps between the plurality of reinforcing fiber sheets 2 is insufficient, impregnation from the inside of the reinforcing fiber sheet 2 does not sufficiently proceed, and impregnation of the prepreg 3 becomes poor. For this reason, the coalescence of the reinforcing fiber sheets 2 is preferably performed below the center of the liquid reservoir 22. When the submerged guide 18 is not used, the plurality of reinforcing fiber sheets 2 are united in a portion where the cross-sectional area of the liquid reservoir 22 is narrowest, that is, near a boundary between the liquid reservoir 22 and the narrowed portion 23. become.

<Width regulation mechanism>
In the above description, the case where the side wall members 24a and 24b play the width regulation is shown. However, as shown in FIG. 9, the width regulating mechanisms 27a and 27b are provided between the side wall members 24a and 24b, and the width of the reinforcing fiber sheet 2 is provided by such a mechanism. Regulations can also be enforced. This is preferable from the viewpoint that prepregs having various widths can be manufactured by one coating portion by allowing the width regulated by the width regulating mechanism to be freely changed. Here, the relationship between the width (W) of the reinforcing fiber sheet immediately below the constriction in FIG. 9B and the width (L2) regulated by the width regulating mechanism at the lower end of the width regulating mechanism is L2 ≦ W + 10 (mm). It is more preferable that L2 ≦ W + 2 (mm). Further, it is preferable to adjust the lower limit of L2 to be not less than W-5 (mm) from the viewpoint of improving the uniformity of the prepreg 3 in the width direction. There is no particular limitation on the shape and material of the width regulating mechanism, but a plate-shaped bush is simple and preferable. On the other hand, from the middle part to the lower part of the width regulating mechanism, it is preferable that the shape conforms to the internal shape of the application part, because the retention of the coating liquid in the liquid pool part can be suppressed and the deterioration of the coating liquid can be suppressed. In this sense, it is preferable that the width regulating mechanism is inserted up to the stenosis 23 as shown in FIG.

幅 Further, it is preferable that the width regulating mechanisms 27 are provided at both ends in the width direction of the plurality of reinforcing fiber sheets 2 so as to be along the traveling path of the reinforcing fiber sheets 2. For example, when running a plurality of reinforcing fiber sheets 2 in a V-shape as shown in FIG. 3, it is preferable that the width regulating mechanism be V-shaped as shown in FIG. 9D.

FIG. 17 is a view of the application unit 20 of FIG. 5 as viewed in the Z direction of FIG. 3, similarly to FIG. 9A, and the positional relationship between the reinforcing fiber sheet 2 and the width regulating mechanism 27 at the upper surface of the liquid reservoir 22. Is shown. In the vicinity of the upper end liquid level of the liquid reservoir 22, as shown in FIG. 17, the width restricting mechanism 27 is divided from each other, that is, the width restricting mechanism 27 corresponds to each of the plurality of reinforcing fiber sheets introduced into the application section. It is preferable to provide a width regulating mechanism so as to form a portion where the mechanism does not exist, and to provide a gap with the wall members 21a, 21b or the side plate members 24a, 24b. Specifically, the distance Lx between the wall surface member 21 and the width regulating mechanism 27 or the distance Ly between the side plate member 24 and the width regulating mechanism 27 is preferably set to 10 mm or more. This prevents the horizontal flow F of the matrix resin 4 so that the matrix resin 4 spreads over the entire area of the liquid reservoir 22, and the liquid surface described in the section of <Reinforcing fiber sheet>. This is because the height difference is reduced, and the effect of stabilizing the running of the reinforcing fiber sheet 2 and improving the degree of impregnation of the prepreg 3 with the matrix resin is obtained.

Further, it is preferable that the dimension E in the thickness direction of the reinforcing fiber sheet 2 of the width regulating mechanism 27 be 10 mm or more on the upper end liquid surface of the liquid reservoir 22. It is more preferably at least 20 mm. This is for preventing the flow F in the horizontal direction from directly hitting the end in the width direction of the reinforcing fiber sheet 2, thereby preventing the end of the reinforcing fiber sheet 2 from being bent or shaken.

FIG. 9 shows an example of a plate-shaped bush as the width regulating mechanism. In FIG. 9D, the lower portion from the position J of the bush extends along the tapered shape of the liquid pool portion 22 and extends to the narrowed portion 23. An example is shown. FIG. 9B shows an example in which L2 is constant from the level of the coating liquid to the exit of the constriction, but the width regulated by the region may be changed in a range that achieves the purpose of the width regulating mechanism. . The width regulating mechanism can be fixed to the application section 20 by any method. However, in the case of a plate-shaped bush, by fixing the plate-shaped bush at a plurality of portions in the vertical direction, even if a high hydraulic pressure is applied, the plate-shaped bush can be fixed. The fluctuation of the regulation width due to the deformation of can be suppressed. For example, it is preferable to use a stay for the upper portion and to insert the lower portion into the application portion, since the width can be easily regulated by the width regulating mechanism.

<Shape of liquid pool>
As described in detail above, in the manufacturing method of the present invention, the liquid pressure is increased in the running direction of the reinforcing fiber sheet 2 by continuously decreasing the cross-sectional area in the Z direction in the liquid reservoir 22. It is important to note that the continuous reduction of the cross-sectional area in the running direction of the sheet-like reinforcing fiber bundle is not particularly limited as long as the hydraulic pressure can be continuously increased in the running direction. In the cross-sectional view of the liquid reservoir, the liquid reservoir may have a curved shape such as a tapered shape (linear shape) or a trumpet shape. In addition, the cross-sectional area decreasing portion may be continuous over the entire length of the liquid pool portion, or may include a portion where the cross-sectional area does not decrease or a portion which expands conversely as long as the object and effects of the present invention can be obtained. You may go out. These will be described in detail below with reference to FIGS. 10 to 13.

FIG. 10 is a detailed cross-sectional view of the application section 20b according to another embodiment different from FIG. It is the same as the application unit 20 in FIG. 5 except that the wall members 21c and 21d constituting the liquid reservoir 22 are different in shape. As in the application part 20b of FIG. 10, the liquid reservoir 22 may be divided into a region 22a in which the cross-sectional area continuously decreases in the vertical downward direction Z and a region 22b in which the cross-sectional area does not decrease. At this time, the vertical height H at which the cross-sectional area is continuously reduced is preferably 10 mm or more. The vertical height H at which the more preferable cross-sectional area is continuously reduced is 50 mm or more. As a result, the distance at which the matrix resin entrained by the reinforcing fiber sheet is compressed in the area 22a where the cross-sectional area of the liquid reservoir 22 is continuously reduced is secured, and the hydraulic pressure generated at the lower portion of the liquid reservoir 22 is reduced. It can be increased sufficiently. As a result, it is possible to prevent the fluff from clogging the constricted portion 23 due to the liquid pressure, and to obtain the effect of impregnating the reinforcing fiber sheet with the matrix resin by the liquid pressure.

Here, when the region 22a in which the cross-sectional area of the liquid reservoir 22 is continuously reduced is tapered like the coating portion 20 in FIG. 5 or the coating portion 20b in FIG. 10, the opening angle θ of the taper is smaller. More specifically, it is preferable to form an acute angle (90 ° or less). Thereby, the compression effect of the matrix resin is enhanced in the region 22a (tapered portion) where the cross-sectional area of the liquid reservoir 22 is continuously reduced, and it is possible to easily obtain a high liquid pressure.

FIG. 11 is a detailed cross-sectional view of the application section 20c of another embodiment different from FIG. It is the same as the application section 20b of FIG. 10 except that the shape of the wall members 21e and 21f constituting the liquid pool section 22 is a two-step tapered shape. As described above, the region 22a where the cross-sectional area of the liquid reservoir 22 is continuously reduced may be configured by a multi-stage taper portion of two or more stages. At this time, it is preferable to make the opening angle θ of the tapered portion closest to the constricted 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 reservoir 22 is continuously reduced is 10 mm or more. The vertical height H at which the more preferable cross-sectional area is continuously reduced is 50 mm or more. As shown in FIG. 11, the area 22 a where the cross-sectional area of the liquid reservoir 22 is continuously reduced is formed as a multi-stage tapered portion, so that the volume of the coating liquid 2 that can be stored in the liquid reservoir 22 is maintained while the constriction 23 is maintained. Can be further reduced. As a result, the liquid pressure generated in the lower part of the liquid reservoir 22 is further increased, and the effect of removing fluff and the effect of impregnating the coating liquid 2 can be further enhanced.

FIG. 12 is a detailed cross-sectional view of the application unit 20d according to another embodiment different from FIG. It is the same as the application section 20b of FIG. 10 except that the shape of the wall members 21g and 21h constituting the liquid pool section 22 is stepped. As described above, if there is a region 22a in which the cross-sectional area is continuously reduced at the lowermost portion of the liquid reservoir 22, 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 reservoir 22 in a shape as shown in FIG. 12, the depth B of the liquid reservoir 22 can be stored while expanding the depth B of the liquid reservoir 22 while maintaining the shape of the region 22 a where the cross-sectional area is continuously reduced. The volume can be increased. As a result, even when the coating liquid 2 cannot be continuously supplied to the coating unit 20d, it is possible to continue to apply the matrix resin to the reinforcing fiber sheet for a long time, and the productivity of the multilayer prepreg is further improved.

FIG. 13 is a detailed cross-sectional view of the application unit 20e according to another embodiment different from FIG. It is the same as the application section 20b in FIG. 10 except that the shape of the wall members 21i and 21j constituting the liquid pool section 22 is a trumpet shape (curved shape). In the application section 20b of FIG. 10, the area 22a where the cross-sectional area of the liquid pool section 22 is continuously reduced is tapered (linear), but is not limited to this. For example, a trumpet shape (curved shape) as shown in FIG. May be. However, it is preferable that the lower part of the liquid pool part 22 and the upper part of the narrow part 23 are connected smoothly. This is because if there is a step at the boundary between the lower part of the liquid pool part 22 and the upper part of the narrow part 23, the reinforcing fiber sheet is caught by the step, and there is a concern that fluff is generated at this part. When the region where the cross-sectional area of the liquid reservoir 22 is continuously reduced is a trumpet-like shape, the opening of the virtual tangent line at the lowermost part of the region 22a where the cross-sectional area of the liquid reservoir 22 is continuously reduced. It is preferable that the angle θ be an acute angle.

In the above description, an example in which the cross-sectional area is smoothly reduced has been described. However, in the present invention, the cross-sectional area of the liquid reservoir does not necessarily have to be smoothly reduced unless the object of the present invention is impaired.

FIG. 14 is a detailed cross-sectional view of the application section 30 of another embodiment. Unlike FIG. 10 to FIG. 13, the liquid reservoir 32 in FIG. 14 does not include a region in which the cross-sectional area continuously decreases in the downward Z direction in the vertical direction, and the cross-sectional area at the boundary 33 with the constriction 23 is discontinuous and sharp. It is a configuration that decreases. For this reason, the reinforcing fiber sheet and the multi-layered prepreg are liable to be clogged.

<Travel mechanism>
As a traveling mechanism for transporting the reinforcing fiber sheet or the multilayer prepreg of the present invention, a known roller or the like can be suitably used. In the present invention, since the reinforcing fiber sheet is transported substantially vertically downward, it is preferable to arrange rollers vertically above and below the application section.

In the present invention, it is preferable that the running path of the reinforcing fiber sheet is as straight as possible in order to suppress the arrangement disorder and the fluffing of the reinforcing fiber. Further, in the step of transporting the sheet-like integrated body which is a laminate of the multilayer structure prepreg and the release sheet, if there is a bent portion, wrinkles may occur due to a difference in the circumferential length between the inner layer and the outer layer. It is also preferable that the traveling route of the vehicle is as straight as possible. From this viewpoint, it is preferable to use a nip roll in the traveling path of the sheet-like integrated object.

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

<High tension take-up device>
In the present invention, it is preferable that a high tension take-off device for drawing out the multilayer prepreg from the application section is disposed downstream of the application section in the process. This is because high frictional force and shear stress are generated between the reinforcing fiber sheet and the matrix resin in the application section, and in order to overcome this and pull out the multilayer prepreg, a high take-up tension must be generated downstream in the process. This is because it is preferable. Nip rolls or S-shaped rolls can be used as the high tension take-off device, but any of them can increase the frictional force between the roll and the multilayer prepreg to prevent slip and enable stable running. Can be. 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 multilayer prepreg against the S-shaped roll. From the viewpoint of preventing the slip, the S-shaped roll is preferable because the frictional force can be easily controlled by the roll diameter and the contact length.

<Release sheet feeding device, winder>
In the production of a prepreg or FRP by the production method of the present invention, a release sheet feeding device or a winder can be used as appropriate, and as such a device, a known device can be used. It is preferable to provide a mechanism capable of feeding back the winding tension or feeding back the winding speed from the viewpoint of stable running of the sheet. In the case of a prepreg (or a multilayer prepreg), the release sheet is bonded to one or both of the upper surface and the lower surface. The term “joining” means “laminate”, and it goes without saying that the release sheet can be peeled off when the prepreg is used.

<Addition impregnation>
In order to adjust the degree of impregnation to a desired degree, it is also possible to combine means for further increasing the degree of impregnation by using an impregnation device after the application of the matrix resin. Here, in order to distinguish it from the impregnation in the application section, additional impregnation after application is referred to as additional impregnation, and an apparatus therefor is referred to as an additional impregnation apparatus. The device used as the additional impregnation device is not particularly limited, and can be appropriately selected from known devices according to the purpose. For example, as described in JP-A-2011-132389 and WO2015 / 060299, a laminate of a reinforcing fiber sheet and a resin is preheated by a hot plate to sufficiently soften the resin on the sheet-like carbon fiber bundle, and then Impregnation can be promoted by using a device that presses with a heated nip roll. The temperature of the hot plate for preheating, the surface temperature of the nip roll, the linear pressure of the nip roll, and the diameter and number of the nip rolls can be appropriately selected so as to obtain a desired impregnation degree. It is also possible to use an "S-wrap roll" in which a prepreg sheet runs in an S-shape as described in WO 2010/150022 pamphlet. In this specification, the “S-wrap roll” is simply referred to as “S-shaped roll”. WO 2010/150022 Pamphlet FIG. 1 shows 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, V-shape or Λ-shape, is described. May be adjusted. When the impregnation pressure is increased to increase the degree of impregnation, it is also possible to add an opposing contact roll. Further, as shown in FIG. 4 of the pamphlet of WO2015 / 076981, it is possible to improve the impregnation efficiency and increase the production speed of the prepreg by arranging the conveyor belt opposite to the “S-wrap roll”. Further, as described in WO 2017/068159 pamphlet or JP-A-2016-20397, it is also possible to improve the impregnation efficiency by applying ultrasonic waves to the prepreg before the impregnation and rapidly raising the temperature of the prepreg. is there. Further, as described in JP-A-2017-154330, it is also possible to use an impregnation device that vibrates a plurality of "ironing blades" with an ultrasonic generator. It is also possible to fold and impregnate the prepreg as described in JP-A-2013-22868.

<Simple additional impregnation>
In the above, an example in which the conventional additional impregnation apparatus is applied has been described.However, the temperature of the multilayer prepreg may be still high immediately below the application section, and in such a case, it takes a long time after leaving the application section. If a re-impregnation operation is added at a stage where it is not performed, a heating device such as a hot plate for reheating the multilayer prepreg can be omitted or simplified, and the impregnation device can be greatly simplified and downsized. Such an impregnating device located immediately below the coating section is referred to as a simple additional impregnating device. As a simple additional impregnating device, a heating nip roll or a heated S-shaped roll can be used, but the roll diameter, the set pressure, and the contact length between the prepreg and the roll can be reduced as compared with a normal impregnating device, and the device can be downsized. This is preferable because power consumption can be reduced as much as possible.

好 ま し い Also, it is preferable to apply a release sheet to the multi-layered prepreg before the multi-layered prepreg enters the simple additional impregnating apparatus, because the running property of the prepreg is improved.

<Width of prepreg>
The method of obtaining a prepreg having a desired width is not particularly limited, and a method of slitting a wide prepreg having a width of about 1 m to 2 m into a narrow width can be used. Further, in order to simplify or omit the slitting 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 manufacturing a narrow prepreg having a width of 30 cm for ATL, the width of the application section outlet may be adjusted accordingly. In addition, in order to manufacture this efficiently, it is preferable to manufacture the product with a product width of 30 cm. When a plurality of such manufacturing devices are arranged in parallel, the same traveling device / transport device, various rolls, and a winder are used. The prepreg of the line can be manufactured.

In the case of a prepreg tape, a reinforcing fiber sheet in the form of a tape-shaped reinforcing fiber bundle having a length of about 1 to 3 threads is formed and passed through a coating section whose width has been adjusted so as to obtain a desired tape width. You can also get it. In the case of a prepreg tape, in particular, the accuracy of the tape width is often required from the viewpoint of controlling the lateral overlap between the tapes. For this reason, it is preferable to more strictly control the outlet width of the application section. 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. .

に お い て In the present invention, the impregnation rate of the coating liquid is desirably 10% or more. The impregnation rate of the coating liquid can be checked for the presence or absence of impregnation by tearing the collected coating liquid impregnated sheet-shaped reinforcing fiber bundle and visually checking the inner layer part, and more quantitatively, for example, it can be evaluated by a peeling method. It is possible. The impregnation rate of the coating liquid by the peeling method can be measured as follows. That is, the collected coating liquid-impregnated sheet-shaped reinforcing fiber bundle is sandwiched between adhesive tapes and peeled off to separate the reinforcing fiber to which the coating liquid has adhered and the reinforcing fiber to which the coating liquid has not adhered. Then, the ratio of the mass of the reinforcing fibers to which the coating liquid has adhered to the mass of the entire sheet-shaped reinforcing fiber bundle that has been input can be used as the impregnation rate of the coating liquid by the peeling method.

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

In addition, when the above-mentioned narrow prepreg and prepreg tape are arranged in a plurality of coating portions in parallel, a release sheet may be supplied independently, or one wide release sheet may be supplied. A plurality of prepregs may be stacked. The end in the width direction of the prepreg thus obtained can be cut off and supplied to an ATL or AFP device. In this case, since most of the cut edge is a release sheet, it is possible to reduce the fluff of the matrix resin and the reinforcing fibers adhering to the slit cutter blade, and there is also an advantage that the cleaning cycle of the slit cutter blade can be extended. .

<Matrix resin supply mechanism>
In the present manufacturing method, the matrix resin is stored in the coating section, but it is preferable to appropriately supply the matrix resin because the coating proceeds. The mechanism for supplying the matrix resin to the application section is not particularly limited, and a known device can be used. It is preferable that the matrix resin be continuously supplied to the application section because the running of the reinforcing fiber sheet can be stabilized without disturbing the liquid level above the application section. For example, self-weight can be supplied as a driving force from a tank storing the coating liquid, or can be supplied continuously using a pump or the like. As the pump, a gear pump, a tube pump, a pressure pump, or the like can be used as appropriate according to the properties of the coating liquid. When the matrix resin is solid at room temperature, it is preferable to provide a melter above the reservoir. Further, a continuous extruder or the like can be used. Further, it is preferable to provide a mechanism capable of continuously supplying the coating liquid in accordance with the amount of the coating liquid so that the liquid level above the coating portion of the coating liquid is as constant as possible. For this purpose, for example, a mechanism that monitors the liquid level, the weight of the application section, and the like and feeds it back to the supply device is conceivable.

<Online monitoring>
Further, it is preferable to provide a mechanism capable of online monitoring of the application amount for monitoring the application amount. The online monitoring method is not particularly limited, and a known method 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 multilayer prepreg and analyzing the difference. The application amount monitored online is immediately fed back to the application unit, and can be used for adjusting the temperature of the application unit and the gap D (see FIG. 5) of the constricted portion 23. Application amount monitoring can of course be used as defect monitoring. As the thickness measurement position, for example, in FIG. 4, the thickness of the reinforcing fiber sheet 416 is measured in the vicinity of the direction change roll 419, and the thickness of the multilayer prepreg 471 is measured between the application section 430 and the direction change roll 441. Can be. It is also preferable to perform online defect monitoring using infrared rays, near infrared rays, a camera (image analysis), or the like.

<Preparation of prepreg>
(1) Pre-Preg Manufacturing Apparatus In the first to fifth embodiments, a pressing guide 14 having the form shown in FIG. 18 was provided using a coating section 20c of the form shown in FIG. Further, as the prepreg manufacturing apparatus, an apparatus having the configuration shown in FIG. 4 (the drawing of the matrix resin supply unit was omitted) was used.

(4) In the application part, a stainless steel block was used for the wall member forming the liquid pool part and the constricted part, and a stainless steel plate was used for the side plate member. The liquid reservoir had a two-step taper shape. The upper taper had an opening angle of 17 °, the taper height (ie, H) was 100 mm, and the lower taper had an opening angle of 7 °. Further, as the width regulating mechanism, a plate-shaped bush adapted to the shape of the inside of the application section as shown in FIG. 9 is provided, and the installation position of the plate-shaped bush can be freely changed to adjust L2 appropriately. did. The width Y of the constricted portion was set to 300 mm when L2 was set to 300 mm. The gap D at the stenosis was 0.2 mm. In this case, the aspect ratio of the exit slit is 1500. The plate-shaped bush used at this time was Y-shaped so that the matrix resin could flow into the central region from the space between the two reinforcing fiber sheets. In addition, in order to prevent the coating liquid from leaking from the stenotic portion outlet, the lower surface of the stenotic portion outlet was closed with the outside of the bush being used. In order to further heat the coating liquid, a plate heater was attached to the outer periphery of the wall members 21e, 21f and the side plate members 24a, 24b, and the temperature and viscosity of the matrix resin were adjusted while measuring the temperature with a thermocouple.

In Examples 6 to 12 and Comparative Example 5, the prepreg manufacturing apparatus shown in FIG. 4 (the drawing section is omitted for the matrix resin supply section) is used, and the pressing guide 14 and the coating section 20f (FIG. 18) are applied to the coating section. The pressing guide 14 and the application section 40 (Comparative Example 5) in the form of Examples 6 to 12) or FIG. 19 were used. In the application part, a stainless steel block was used for the wall member forming the liquid pool part and the constricted part, and a stainless steel plate was used for the side plate member. The liquid reservoir had a two-stage tapered shape. The upper taper had an opening angle of 17 °, the lower taper had an opening angle of 7 °, and the total taper height (ie, H) was 100 mm. The width Y of the constriction was 300 mm, and the gap D of the constriction was 0.2 mm. In this case, the aspect ratio of the exit slit is 1500. In order to further heat the matrix resin, a plate heater was attached to the outer periphery of the wall members 21e and 21f and the side plate members 24a and 24b, and the temperature of the matrix resin was maintained at 90 ° C. while measuring the temperature with a thermocouple. Table 2 is a table summarizing the experimental results of preparing prepregs for CFRP in Examples 6 to 8 and Comparative Example 5, and evaluating running stability and impregnation degree. As a common implementation condition for Examples 6 to 8 and Comparative Example 5, the width regulating mechanism was not used.

(2) Reinforcing fiber sheet As the reinforcing fiber sheet, two UD base materials in which carbon fibers (manufactured by Toray, Torayca T800S (24K)) are arranged are formed, and a thermosetting epoxy resin composition described later as a matrix resin is used. Using this apparatus, a multilayer prepreg for CFRP was produced by the above apparatus. Although the number of the reinforcing fiber bobbins 412 was adjusted according to the prepreg to be produced, the number was set at 29 bobbins per reinforcing fiber sheet unless otherwise specified.

(3) Prepreg Production Method Reinforcing fibers were drawn from a plurality of reinforcing fiber bobbins hung on a creel, two reinforcing fiber sheets were formed by a reinforcing fiber arrangement device, and once guided upward by a direction change roll. Thereafter, the wafer was conveyed vertically downward via a direction change roll, and was preheated by a preheating device to a temperature equal to or higher than the matrix resin temperature in the application section. Then, using a holding guide, the incident angle α and the incident position were adjusted so that the two reinforcing fiber sheets were symmetrical, and at this time, Lb / Ln was led to the application section so as to be 2 (however, If there is special mention, it was adjusted to Lb / Ln). Thereafter, the matrix resin was applied and impregnated in the application section, respectively, and united into a single sheet in the vicinity of the constricted portion in the application section to form a multilayer prepreg. The multilayer prepreg was laminated on a direction change roll with a release sheet unwound from a release sheet (upper) supply device, and was taken up by a high tension take-off S-shaped roll. At the same time, the release sheet unwound from the release sheet (lower) supply device was laminated on a high tension take-off S-shaped roll, and the release sheets were arranged on both upper and lower surfaces of the multilayer prepreg. Then, this was supplied to a re-inclusion device and pre-heated by a hot plate, followed by additional impregnation using a heated nip roll. Thereafter, after being cooled by a cooling device, the upper release sheet was peeled off via a take-off device, and the multilayer structure prepreg / release sheet was wound into a roll shape by a winder. However, in Comparative Example 5, a prepreg was prepared by introducing the reinforced fiber sheets that were superimposed on each other into the application section.

(4) Matrix resin Thermosetting epoxy resin composition 1 (matrix resin A):
It is a mixture of an epoxy resin (a mixture of an aromatic amine type epoxy resin and a bisphenol type epoxy resin), a curing agent (diaminodiphenyl sulfone), and a polyether sulfone, and does not contain polymer particles. The viscosity of the thermosetting epoxy resin 1 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 15 ° C. and 4 Pa · s at 105 ° C.

Thermosetting epoxy resin composition 2 (matrix resin B):
A mixture of an epoxy resin (a mixture of an aromatic amine type epoxy resin and a bisphenol type epoxy resin), a curing agent (diaminodiphenyl sulfone), and a polyether sulfone was used as polymer particles as polymer particles described in Examples of JP-A-2011-162609. 3 "(Tg = 150 ° C.) was added so as to be 12% by mass when the mass of the entire resin composition was 100% by mass.

The viscosity of the thermosetting epoxy resin 2 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. Was 32 Pa · s at 105 ° C. and 10 Pa · s at 105 ° C.

<Prepreg evaluation method>
(1) Evaluation of Layer Structure of Prepreg The prepreg was frozen at −18 ° C. in a freezer, taken out of the freezer, and then quickly cut at room temperature using a cutter to prepare a prepreg cross section in the thickness direction. This sample was observed using a VHX-5000 manufactured by KEYENCE CORPORATION as a scanning electron microscope.

(2) Degree of matrix resin impregnation of prepreg (water absorption of prepreg)
The degree of impregnation in Examples 1 to 5 and Comparative Examples 1 to 4 can be evaluated from the water absorption of the prepreg by capillary action, and the prepreg is cut into 10 cm × 10 cm in accordance with the method described in JP-T-2016-510077. Calculated from the change in mass when one side was immersed in water for 5 minutes at 5 mm. The lower the water absorption, the higher the impregnation.

プ リ The impregnation degree of the prepregs of Examples 6 to 12 and Comparative Example 5 was quantitatively evaluated by the impregnation degree peeling method. The impregnation degree of the coating liquid by the peeling method was measured as follows. That is, the collected prepreg is sandwiched between adhesive tapes, and the prepreg is peeled off to separate the reinforcing fibers to which the matrix resin has adhered from the reinforcing fibers to which the matrix resin has not adhered. Then, the ratio of the mass of the reinforcing fibers to which the matrix resin adhered to the total mass of the loaded reinforcing fiber sheet was determined as the degree of impregnation of the matrix resin by the peeling method.

(3) Shape Preservability of Prepreg A. Adhesion of prepreg / release paper in prepreg production process In the prepreg / release paper transport process in the prepreg production process, release paper with 0 times of peeling per 400 m travel is “Good” and 1 time is “Fair” "Bad" was used twice or more times.

B. Prepreg roll shape retention A prepreg having release paper laminated on one side is rolled up into a 400 m roll shape, and this roll is placed vertically and left at 20 ° C. and 65% RH for 24 hours. Those having a length in the direction (peeling distance) of less than 5 cm were “Good”, those having a peeling distance of 5 cm or more and less than 30 cm were “Fair”, and those having a peeling distance of 30 cm or more were “Bad”.

In addition, the unimpregnated layer of the prepreg, that is, "Good" when the peeling distance of the prepreg at the dry reinforcing fiber or void portion is less than 5 cm, "Fair" when the peeling distance is 5 cm or more and less than 30 cm, and "Fair" when the peeling distance is 30 cm or more. Was designated as "Bad".

C. Prepreg shape retention in prepreg lamination process Evaluate peeling and displacement of unimpregnated layer of prepreg when 16 prepregs (using UD substrate) of 30 cm square are laminated in one direction, that is, dry reinforcing fibers and voids did. "Good" means that one or less layers were peeled or displaced, "Fair" means that two or three layers were peeled or displaced, and "Bad" means that four or more layers were peeled or displaced.

D. Fuzz at the time of cutting prepreg When the prepreg was cut into 16 squares of 30 cm square, two or less places where reinforcing fiber fuzz occurred on the cut surface were "Good" and three to four places Is "Fair", and five or more are "Bad".

(4) Vacuum pressure formability After prepregs (using a UD base material) of 30 cm square are laminated in 16 directions in one direction to form a prepreg laminate, a PTFE film having a thickness of 100 μm is arranged on both surfaces of the prepreg laminate. Was placed on a 10 mm thick aluminum plate and covered with a polyamide film. Further, in a 25 ° C. environment, the degree of vacuum around the prepreg laminate was set to 3 kPa, and the mixture was left for 3 hours to remove volatile components. Thereafter, while maintaining the degree of vacuum at 3 kPa, the temperature was raised to 120 ° C. at a rate of 1.5 ° C./min, and held for 180 minutes. Thereafter, the temperature was further raised to 180 ° C. at a rate of 1.5 ° C./minute, and the temperature was maintained for 120 minutes to cure the matrix resin to obtain CFRP.

Three sample pieces of 1 cm long and 1 cm wide were cut out from this CFRP, and after polishing the cross-section, the images were obtained by observing with an optical microscope using a 50 × lens so that the upper and lower surfaces of the CFRP were within the field of view. . The ratio of the void area to the total cross-sectional area was calculated from the obtained image, and the void ratio of each image was calculated. The same operation was performed to calculate the void ratios at three locations for each sample piece, that is, at a total of nine locations, and the average value was used as the void ratio at each evaluation level. An average void fraction of less than 1% was “Good”, 1% or more and less than 2% was “Fair”, and 2% or more was “Bad”.

(5) Process stability of the prepreg manufacturing process In order to evaluate the running stability of the reinforcing fiber sheet in the application section in each of the examples and comparative examples, the state of the reinforcing fiber sheet near the liquid surface at the upper end of the liquid reservoir, the reinforcing fiber The liquid level difference between the front and back of the sheet and the state of the fluff circulating in the liquid pool were observed. In the vicinity of the liquid level at the upper end of the liquid pool, a difference in liquid level occurs between the front and back of the reinforcing fiber sheet, and a breakage of the fiber bundle is observed over the entire width of the reinforcing fiber sheet due to the inflow of the matrix resin. “Good” indicates that fiber bundles are not cracked but fuzz is circulating in the liquid pool, and no fiber bundle cracks or fuzz in the liquid pool are seen. A sample having a difference in surface height was designated as "Very Good", and a sample having no difference in the liquid surface height of less than 5 mm without cracking of the fiber bundle or fuzz in the liquid pool was designated as "Excellent".

In addition, if the obtained prepreg has broken or broken fiber bundles at the end (a region where no reinforcing fiber is present in the prepreg and only the matrix resin is present), the quality of the end is "Fair" and the fiber bundle is broken. "Good" means that the obtained prepreg has uneven thickness of the reinforcing fiber at the end, and "Excellent" means that the reinforcing fiber has a uniform thickness without breaking or cracking of the fiber bundle. "

[Example 1]
A thermosetting epoxy resin composition 1 (matrix resin A) was used as a matrix resin, and a 300 mm wide multilayer prepreg was prepared with a distance L2 between lower ends of 300 mm as a width regulating mechanism. However, here, the hot plate and heating nip roll of the additional impregnation device were not used, and additional impregnation was not performed. The temperature of the coating liquid in the liquid pool was 90 ° C. (corresponding to 15 Pa · s). The running speed of the reinforcing fiber sheet and the multilayer prepreg was 10 m / min.

Observation of the cross section of the obtained multilayer prepreg by SEM showed a layer structure of impregnated layer / unimpregnated layer / impregnated layer / unimpregnated layer / impregnated layer, and the maximum value of the unimpregnated portion ratio was 54%. Met. In addition, the cross-sectional area of the void and the dry reinforcing fiber aggregate included in the unimpregnated layer was at most 320 μm ² . As a result, the multilayer prepreg obtained as shown in Table 1 exhibited excellent handling properties.

In addition, since the used reinforcing fiber sheet was a UD base material arranged according to the same standard, the arrangement of the reinforcing fibers in the obtained multilayer structure prepreg in the plane direction was substantially the same throughout the thickness direction of the prepreg. Met.

In addition, since this multilayer prepreg had an unimpregnated layer, the voids in vacuum formability were sufficiently small. Further, the CFRP obtained by the present vacuum pressing 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 WO2011 / 118106, and the value obtained by standardizing the volume% of the reinforcing fibers in the prepreg to 56.5% was used.

[Example 2]
A multi-layer prepreg was produced in the same manner as in Example 1 except that thermosetting epoxy resin 2 (matrix resin B) was used as the matrix resin, and the coating liquid temperature in the liquid reservoir was 105 ° C. After this experiment, the resin remaining between the width control devices in the application section was sampled, dissolved with a solvent using a solvent, filtered, and polymer particles were separated by filtration, and the mass was measured. According to this, it was determined that the polymer particles had passed through the coating portion and that the polymer particles had mostly passed through the coating portion, and were applied to the prepreg.

Observation of the cross section of the obtained multilayer prepreg by SEM showed a layer structure of impregnated layer / unimpregnated layer / impregnated layer / unimpregnated layer / impregnated layer, and the maximum value of the unimpregnated portion ratio was 56%. Met. In addition, the cross-sectional area of the void and the dry reinforcing fiber aggregated portion contained in the unimpregnated layer was 350 μm ² at the maximum. As a result, the multilayer prepreg obtained as shown in Table 1 exhibited excellent handling properties.

In addition, since the reinforcing fiber sheet used was a UD base material arranged according to the same standard, the arrangement of the reinforcing fibers in the obtained multilayer structure prepreg in the planar direction was substantially over the entire thickness direction in the prepreg. Were identical.

[Example 3]
Except that the re-impregnation device equipped with a hot plate and a heating nip roll was operated and used, the multi-layer prepreg was impregnated with the matrix resin by the method described in Example 2, and subsequently led to the re-impregnation device, Additional impregnation was performed in-line with reference to JP-A-2011-132389. The water absorption of the obtained prepreg was 4%. When the cross section of the obtained multilayer prepreg was observed by SEM, it had a layer structure of impregnated layer / unimpregnated layer / impregnated layer / unimpregnated layer / impregnated layer, and the maximum value of the unimpregnated portion ratio was 20%. Met. The cross-sectional area of the voids and the dry reinforcing fiber aggregate included in the unimpregnated layer was at most 100 μm ² . As a result, the multilayer prepreg obtained as shown in Table 1 exhibited excellent handling properties. Also, the voids in the vacuum pressure formability of this multilayer prepreg were small.

[Comparative Examples 1 and 2]
With reference to the description of Patent Document 2, matrix resin A is applied on release paper to prepare a matrix resin film, and this is a UD having a width of 30 cm corresponding to a laminate of two reinforcing fiber sheets used in Example 1. The prepreg was sandwiched from both sides of the base material and impregnated with an impregnating machine to change the degree of impregnation.

In Comparative Example 1, an unimpregnated layer was not formed because the matrix resin was completely impregnated.

In Comparative Example 2, a prepreg having a three-layer structure of an impregnated layer / unimpregnated layer / impregnated layer was obtained. However, since the impregnated layer in the central portion was thick, the handleability was poor due to peeling and displacement of the unimpregnated layer. . Further, although the degree of impregnation was variously changed, it was not possible to achieve both vacuum pressure formability and handleability.

[Comparative Example 3]
Referring to JP-A-2012-167230, the matrix resin A also used in Example 1 was applied using a die coater on the reinforcing fiber sheet used in Example 1, and then used in Example 1. The reinforced fiber sheets were stacked and sandwiched between release papers from above and below. Then, this was impregnated using an impregnating machine, the degree of impregnation was adjusted, and an unimpregnated portion was left to produce a three-layer prepreg having an unimpregnated layer / impregnated layer / unimpregnated layer. However, since the prepreg surface is an unimpregnated layer, there is a problem that the prepreg is easily peeled off from the release paper. In addition, since the unimpregnated layers of the prepreg are laminated during the prepreg lamination, the adhesion between the prepregs is poor, and the prepregs are peeled or displaced from each other, resulting in poor handleability.

[Examples 4 and 5 and Comparative Example 4]
The prepreg / release sheet obtained in Examples 1 and 3 and Comparative Example 1 were slit to obtain a 7 mm wide prepreg tape. The prepreg tapes of Example 4 (the prepreg of the multilayer structure of Example 1) and 5 (the prepreg of the multilayer structure of Example 3) had less fluff in the slitter than the prepreg of Comparative Example 4 (the prepreg of Comparative Example 1). Was.

[Example 6]
Using the holding guide 14 and the application unit 20f shown in FIG. 18, two reinforcing fiber sheets are put into the liquid reservoir 22 at intervals in the thickness direction, and the matrix resin is applied and impregnated. To form one prepreg. The reinforcing fiber sheet was adjusted using the holding guide 14 so that the incident angle and the position of the reinforcing fiber sheet with respect to the liquid reservoir 22 were symmetrical. At this time, the distance between the wall member 21 and the reinforcing fiber sheet 2 was 20 mm, and the distance between the reinforcing fiber sheets 21 was 100 mm (Lb / Ln = 5).

When observing the state of the application part, the liquid level in the region sandwiched between the wall member and the reinforcing fiber sheet suddenly dropped, and a liquid surface height difference of 20 mm or more occurred on the front and back of the reinforcing fiber sheet, and the matrix resin Due to the inflow, cracks of the fiber bundle were observed in the reinforcing fiber sheet over the entire width (running stability “Fair”). The degree of impregnation of the obtained prepreg with the matrix resin was 85%.

[Comparative Example 5]
A prepreg was produced using the pressing guide 14 and the application section 40 shown in FIG. 19 having a different form from the present invention. The difference from the sixth embodiment is that the position of the holding guide 14 and the traveling path of the reinforcing fiber sheet 2 are adjusted, and the reinforcing fiber sheet is united and put into the liquid reservoir 22 before being put into the application unit 40. The degree of impregnation of the obtained prepreg with the matrix resin was 60%.

[Example 7]
A prepreg was produced using the pressing guide 14 and the application section 20f shown in FIG. 18 according to the present invention. The position of the holding guide 14 was adjusted from Example 6, and the distance between the wall member 21 and the reinforcing fiber sheet 2 was set to 28 mm, and the distance between the reinforcing fiber sheets 21 was set to 84 mm (Lb / Ln = 3). When observing the state of the application part, the liquid level in the region sandwiched between the wall member and the reinforcing fiber sheet was lowered, and a liquid surface height difference of about 10 mm occurred on the front and back of the reinforcing fiber sheet. No cracks were found in the fiber bundle. Further observation of the liquid reservoir 22 revealed that fluff was observed near the upper end liquid level (running stability "Good"). The degree of impregnation of the obtained prepreg with the matrix resin was 85%.

Example 8
A prepreg was produced using the pressing guide 14 and the application section 20f shown in FIG. 18 according to the present invention. The position of the holding guide 14 was further adjusted from that of Example 7, and the distance between the wall member 21 and the reinforcing fiber sheet 2 was 35 mm, and the distance between the reinforcing fiber sheets 21 was 70 mm (Lb / Ln = 2). When observing the state of the application part, the liquid level in the region sandwiched between the wall member and the reinforcing fiber sheet was lowered, and a liquid surface height difference of about 5 mm was generated on the front and back of the reinforcing fiber sheet. No cracks were found in the fiber bundle. Also, no fuzz was found in the liquid reservoir 22 (running stability "Very Good"). The degree of impregnation of the obtained prepreg with the matrix resin was 85%.

Table 3 is a table summarizing the experimental results of preparing prepregs for CFRP in Examples 9 to 12 and evaluating the running stability of the reinforcing fiber sheet and the quality of the obtained prepreg end. As an implementation condition common to Examples 9 to 12, two reinforcing fiber sheets are introduced into the liquid reservoir 22 at an interval in the thickness direction, and the interval between the wall surface member 21 and the reinforcing fiber sheet 2 is 35 mm. The spacing between the reinforcing fiber sheets 21 was set to 70 mm (Lb / Ln = 2). In Examples 9 to 12, the width regulating mechanism 27 (plate-shaped bush) as shown in FIG. 9 was used, and the width L2 regulated by the width regulating mechanism at the lower end of the width regulating mechanism 27 was set to 300 mm. The width regulating mechanism 27 has a V-shape as shown in FIG. 9D, and the dimensions Lx, Ly, and E of each part in FIG. 18 are different for each embodiment. In order to prevent the matrix resin from leaking from the stenotic portion outlet, the lower surface of the stenotic portion outlet was closed with the outside of the plate-shaped bush.

[Example 9]
A prepreg was produced using the application section 20f in FIG. 18 and the width regulating mechanism 27 in FIG. Referring to FIG. 17, the distance Lx = Ly = 5 mm between the wall member or the side plate member and the width regulating mechanism 27, and the dimension E in the thickness direction of the reinforcing fiber sheet of the width regulating mechanism is set to 5 mm. When observing the state of the application part, the liquid level in the region sandwiched between the wall member and the reinforcing fiber sheet was lowered, and a liquid surface height difference of about 5 mm was generated on the front and back of the reinforcing fiber sheet. No cracks were found in the fiber bundle. Also, no fuzz was found in the liquid reservoir 22 (running stability "Very Good"). When the obtained prepreg was sampled and observed, the fiber bundle was continuously broken and cracked at the width direction end of the prepreg (the quality of the end was “Fair”).

[Example 10]
A prepreg was produced using the application section 20f in FIG. 18 and the width regulating mechanism 27 in FIG. By changing the shape of the width regulating mechanism 27 from the ninth embodiment and referring to FIG. 17, the distance Lx = Ly = 10 mm between the wall member or the side plate member and the width regulating mechanism 27, the thickness of the reinforcing fiber sheet of the width regulating mechanism The dimension E in the direction was 5 mm. Observation of the state of the application portion showed that the difference in liquid level between the front and back surfaces of the reinforcing fiber sheet was less than 5 mm, and no cracks in the fiber bundle were found in the reinforcing fiber sheet. Also, no fuzz was found in the liquid reservoir 22 (running stability "Excellent"). When the obtained prepreg was sampled and observed, the fiber bundle was continuously broken and cracked at the width direction end of the prepreg (the quality of the end was “Fair”).

[Example 11]
A prepreg was produced using the application section 20f in FIG. 18 and the width regulating mechanism 27 in FIG. Referring to FIG. 17, the shape of the width regulating mechanism 27 is further changed from that of the fifth embodiment. The distance Lx = Ly = 10 mm between the wall surface member or the side plate member and the width regulating mechanism 27, and the reinforcing fiber sheet of the width regulating mechanism is used. The dimension E in the thickness direction was set to 10 mm. Observation of the state of the application portion showed that the difference in liquid level between the front and back surfaces of the reinforcing fiber sheet was less than 5 mm, and no cracks in the fiber bundle were found in the reinforcing fiber sheet. Also, no fuzz was found in the liquid reservoir 22 (running stability "Excellent"). In addition, when the obtained prepreg was sampled and observed, the fiber bundle was not broken or cracked at the end in the width direction of the prepreg, but the thickness unevenness of the reinforcing fiber was observed (the quality of the end was “Good”). .

[Example 12]
A prepreg was produced using the application section 20f in FIG. 18 and the width regulating mechanism 27 in FIG. Referring to FIG. 17, the shape of the width regulating mechanism 27 is further changed from that of the eleventh embodiment. The space Lx = Ly = 10 mm between the wall member or the side plate member and the width regulating mechanism 27 is used. The dimension E in the thickness direction was set to 20 mm. Observation of the state of the application portion showed that the difference in liquid level between the front and back surfaces of the reinforcing fiber sheet was less than 5 mm, and no cracks in the fiber bundle were found in the reinforcing fiber sheet. Also, no fuzz was found in the liquid reservoir 22 (running stability "Excellent"). Further, when the obtained prepreg was sampled and observed, no breakage or cracking of the fiber bundle was observed at the end in the width direction of the prepreg, and the thickness of the reinforcing fiber was uniform (the quality of the end was "Good").

The multilayer prepreg of the present invention has both the vacuum pressure formability of FRP typified by CFRP and the handleability as a prepreg, and structural materials and interior materials such as aviation / space applications and automobiles / trains / ships, pressure vessels, It can be widely used for industrial materials, sports materials, medical equipment, housing, civil engineering and construction.

REFERENCE SIGNS LIST 1 reinforced fiber 2 reinforced fiber sheet 3 multilayer prepreg / prepreg 4 matrix resin 5a, 5b release sheet 11 creel 12 arranging device 13 transport roll 14 holding guide 15 take-off rolls 16a, 16b release sheet supply device 17 winding device 18 liquid Middle guide 20 Coating section 20a Coating section 20b of another embodiment Coating section 20c of another embodiment Coating section 20d of another embodiment Coating section 20e of another embodiment Coating section 20f of another embodiment Another embodiment Coating portions 21a, 21b wall members 21c, 21d different wall members 21e, 21f different wall members 21g, 21h different wall members 21i, 21j different wall members 22 liquid reservoir 22a liquid Area 22b of the reservoir where the cross-sectional area is continuously reduced. The area 22c where the cross section is not intermittently reduced in the liquid reservoir area 23 The constriction parts 24a, 24b The side plate member 25 The outlet 26 The gaps 27, 27a, 27b The width regulating mechanism 30 The application part 31a of the embodiment different from the present invention, 31b Wall member 32 of coating section 30 Liquid pool section 33 of coating section 30 Areas 35a, 35b, 35c of the liquid pool section of coating section 30 where the cross-sectional area decreases intermittently Bar 100 Coating apparatus B of liquid storage section 22 Depth C Height to the upper liquid level of the liquid reservoir 22 D Gap of the constriction E Dimension F in the thickness direction of the reinforcing fiber sheet of the width restricting mechanism 27 F Flow in the horizontal direction G Position where the width is restricted H Position of the liquid reservoir 22 The vertical height J in which the cross-sectional area continuously decreases The upper end line L at a position where the width regulating mechanism 27 follows the tapered shape The width L2 of the liquid reservoir 22 The width regulating mechanism at the lower end of the width regulating mechanism Ln The narrowest distance Lb at the upper end liquid level The widest distance Lx at the upper end liquid level The distance Ly between the side wall members and the width restricting mechanism Ly between the side plate members and the width regulating mechanism R, Ra, Rb Vortex flow T Circulating flow T 'Circulating flow W Width of prepreg 1b measured just below constriction 23 Width Z of constriction 23 Traveling direction of sheet-like reinforcing fiber bundle 1a (vertically downward)
α The angle between the Z direction (vertical line) and the running direction of the reinforcing fiber sheet θ The opening angle of the tapered portion 411 Creel 412 The reinforcing fiber bobbin 413 The direction changing guide 414 The reinforcing fiber 415 The reinforcing fiber array device 416 The reinforcing fiber sheet 417 The widening device 418 Smooth Forming device 419 direction changing roll 420 preheating device 421 pressing guide 430 coating section 441 direction changing roll 442 release sheet (upper) supply device 443 release sheet (lower) supply device 445 direction changing roll 446 release sheet 447 laminating roll 449 high Tension take-up S-shaped roll 450 Additional impregnation device 451 Heat plate 452 Heating nip roll 453 Simple additional impregnation device 461 Cooling device 462 Removal device 463 Release sheet (upper) winding device 464 Winder 471 Pre-preg 472 Pre-preg / release sheet

Claims (13)

In a multilayered prepreg in which a reinforcing fiber sheet is impregnated with a matrix resin and a non-impregnated layer are alternately laminated, the upper and lower surfaces of the multilayered prepreg are constituted by an impregnated layer, and the upper and lower surfaces are excluded. A multilayer prepreg with a release sheet, comprising at least one impregnated layer in an inner layer portion of the multilayer prepreg, and a release sheet bonded to one or both of the upper surface and the lower surface of the multilayer prepreg. The multilayer prepreg with a release sheet according to claim 1, wherein the arrangement of the reinforcing fibers in the planar direction is substantially the same in the multilayer prepreg. A prepreg roll formed by winding the multilayer prepreg with the release sheet according to claim 1 or 2. A prepreg tape having a width of 30 mm or less, comprising the multilayer prepreg with the release sheet according to claim 1 or 2. A composite material obtained by molding the multilayer prepreg with a release sheet according to claim 1 or 2, a prepreg roll according to claim 3, or a prepreg tape according to claim 4. Matrix resin as a coating liquid is stored, and a liquid reservoir portion having a portion where the cross-sectional area is continuously reduced vertically downward, and a narrowed portion having a slit-shaped outlet communicating with the lower end of the liquid reservoir, A method for producing a prepreg, in which a reinforcing fiber sheet is passed vertically downward through an application section provided, and a coating liquid is applied to the reinforcing fiber sheet, wherein a plurality of reinforcing fiber sheets are spaced in the thickness direction in the liquid reservoir. And a step of unifying the plurality of reinforcing fiber sheets inside the application section after the introduction. In the upper end liquid level of the liquid reservoir, the narrowest distance Ln and the widest distance Lb among the distance between the wall surface (wall member) of the liquid reservoir and the reinforcing fiber sheet and the distance between the plurality of reinforcing fiber sheets. The prepreg manufacturing method according to claim 6, wherein the relationship satisfies 1 ≦ Lb / Ln ≦ 3. 8. The prepreg according to claim 6, wherein a width regulating mechanism is provided in the liquid reservoir in correspondence with both ends in the arrangement direction of the plurality of reinforcing fiber sheets, and regulates the width of the reinforcing fiber sheet. 9. Method. The prepreg manufacturing method according to claim 8, wherein the width regulating mechanism is divided from each other at a liquid surface at an upper end of the liquid reservoir. The method for producing a prepreg according to claim 8, wherein an interval between the width regulating mechanism and a wall surface (wall member) of the liquid reservoir is 10 mm or more on a liquid surface at an upper end of the liquid reservoir. The method of manufacturing a prepreg according to claim 8, wherein the width regulating mechanism extends from a lower end of the liquid reservoir to an upper end liquid surface. The method for producing a prepreg according to any one of claims 8 to 11, wherein a dimension of the width regulating mechanism with respect to a thickness direction of the reinforcing fiber sheet is 10 mm or more at a liquid surface at an upper end of the liquid reservoir. A prepreg manufacturing apparatus for applying a matrix resin as a coating liquid to the reinforcing fiber sheet, and a liquid pool that has a portion in which the coating liquid can be stored, and the cross-sectional area decreases continuously downward in the vertical direction, An application section having a narrowed section having a slit-shaped outlet communicating with the lower end of the liquid pool section, and a plurality of reinforcing fiber sheets running vertically downward with an interval in the thickness direction thereof, and introduced into the application section. A prepreg comprising: a traveling mechanism having an introduction mechanism for introducing a prepreg derived from the constriction and a deriving mechanism for extracting the prepreg derived from the constriction; manufacturing device.

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