JP3323373B2 - Method of manufacturing honeycomb core made of fiber reinforced plastic - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for manufacturing a honeycomb core made of fiber reinforced plastic. That is,
Fiber reinforced plastic (FR
The present invention relates to a method for manufacturing a honeycomb core made of P).

[0002]

2. Description of the Related Art A honeycomb core made of fiber reinforced plastic is generally manufactured by the following steps. That is, a prepreg sheet made of a fiber-reinforced plastic as a base material is supplied to a corrugating device such as a gear or a rack and heated and pressurized to form a corrugated sheet. And the top portion were stacked and joined in a positional relationship to match the top portion, thereby obtaining a honeycomb core made of fiber-reinforced plastic, which was a planar aggregate of hollow columnar cells defined by corrugated plates as cell walls. .

[0003] As for gears and racks of a corrugating apparatus used for manufacturing such a honeycomb core, conventionally, silicone, fluorine resin, other release agents and non-adhesives are baked on the mold surface, The resin adhered and coated, thereby preventing the resin that oozes out of the prepreg sheet formed into a corrugated sheet by heating and pressing and flows and adheres to the mold surface. In other words, in this kind of conventional manufacturing method, the release agent or the non-adhesive which has been baked, adhered or coated in this manner causes the corrugating device to mold the gear or rack into a prepreg sheet. This prevents the resin from adhering and the prepreg sheet from adhering.

[0004]

The following problems have been pointed out in such a conventional example. First, the release agent or non-adhesive which is baked, adhered and coated on the mold surface such as gears and racks of the corrugated molding machine,
The prepreg sheet was gradually scraped, worn, and deteriorated in accordance with the bending of the prepreg sheet, and the releasability was easily reduced, and the prepreg sheet was easily peeled off and adhered to the prepreg sheet side. Further, the release agent and the non-adhesive which have been baked, adhered and coated in this manner are originally difficult to be formed to have the same uniform thickness, and even if the same product is used, there is a great difference in durability.
There were many difficulties in the releasability, which originally functions, such as a difference in releasability easily caused by heating. Accordingly, the prepreg sheet is likely to adhere to the mold surface, and the prepreg sheet is likely to be damaged or deteriorated. As a result, quality problems are likely to occur in the corrugated sheet to be formed and the honeycomb core made of fiber reinforced plastic to be manufactured. Was.

Second, even if the release agent or the non-adhesive which is baked, adhered or coated on the mold surface functions normally,
Through these, the corrugated sheet is bent and formed from the prepreg sheet by being heated and pressurized by a gear, a rack, or the like of the corrugating apparatus, and the outer surface thereof is mirror-finished.
In other words, the outer surface of the formed corrugated sheet exudes due to heating and pressurization, and the flowed resin is hardened, so that it is completely flat and smoothly mirror-finished. Therefore, a problem has been pointed out that when the corrugated sheets are stacked and joined in the next step due to the mirror surface of the outer surface, for example, it is difficult to obtain an adhesive effect by an adhesive. In other words, it is pointed out that the bonding strength between the corrugated sheets having a mirror-finished outer surface is difficult even when an adhesive is interposed, and the honeycomb core made of fiber-reinforced plastic is manufactured. In addition, there is concern about the bonding strength between the cell walls formed by the corrugated sheet, and the cell walls are easily peeled off, which also causes a problem in quality.

Third, regarding the manufactured honeycomb core made of fiber-reinforced plastic, a resin is often attached to and impregnated on the outer surface of the cell wall as a post-treatment for reinforcement. However, since the cell wall of the honeycomb core, that is, the outer surface of the corrugated plate is mirror-finished as described above, the adhesion of the resin to be adhered and impregnated as a post-treatment is poor, and the resin adhered and impregnated after the treatment This type of honeycomb core made of fiber reinforced plastic has been pointed out as having a problem in quality from this aspect, for example, cracks, cracks, cracks, peeling and the like are likely to occur. Conventionally, as a countermeasure against such a problem, it has been attempted to improve the adhesion of a resin adhered and impregnated afterward by blasting a mirror-finished outer surface of a cell wall of a honeycomb core. , Because additional processes such as blasting process and accompanying cleaning process are added,
In addition to the problem of manufacturing cost, the blast material used for blasting tends to remain on and adhere to the cell wall side of the honeycomb core, and there is also a problem in the product quality of the honeycomb core. Therefore, it has been evaluated that the conventional example of performing blasting in this way cannot be a fundamental solution to the problem.

The present invention has been made in view of such circumstances, and has been made to solve the problems in the above-described conventional example.
The prepreg sheet is sandwiched between the cross sheet and the resin adsorption sheet from both sides and molded into a corrugated sheet. First, the releasability of the corrugating apparatus to gears and racks is secured, and the prepreg sheet is peeled off. Second, without worrying about
Thirdly, the bonding strength between the corrugated sheet and the cell wall is improved, and thirdly, the adhesion of the resin adhered and impregnated as a post-treatment is excellent, and
Another object of the present invention is to propose a method for manufacturing a honeycomb core made of fiber-reinforced plastic, which can realize these easily and easily.

[0008]

The technical means of the present invention for solving such a problem is as follows. First, claim 1 is as follows. In other words, in the method for manufacturing a honeycomb core made of fiber reinforced plastic, a prepreg sheet made of fiber reinforced plastic, which is a base material, is provided with a gas-permeable cross-sheet subjected to a release treatment and a resin adsorption having release properties. The sheet is sandwiched from both sides in two layers, and then supplied to a corrugating device such as a gear or a rack. By heating and pressing from both sides, the corrugated unevenness is continuously bent and the outer surface is formed. A roughened corrugated sheet is formed. Then, after removing the cross sheet and the resin adsorption sheet, a plurality of the corrugated sheets are stacked and joined in a positional relationship where the valley portion and the top portion are aligned, thereby forming the corrugated plate as a cell wall. Thus, a honeycomb core as a planar assembly of hollow columnar cells is obtained.
Next, claim 2 is as follows. That is, in the method for producing a fiber-reinforced plastic honeycomb core according to claim 2, the method for producing a fiber-reinforced plastic honeycomb core according to claim 1 further includes:
Resin adheres to and impregnates the outer surface of the cell walls of the honeycomb core.

As described above, in the manufacturing method according to the present invention, first, a prepreg sheet made of fiber reinforced plastic is sandwiched from both sides by a cloth sheet and a resin adsorption sheet, and then supplied to a corrugating apparatus and heated and heated. By pressing, a corrugated sheet whose outer surface is roughened is formed. Then, after removing the cross sheet and the resin adsorption sheet, a plurality of corrugated sheets are stacked and joined to obtain a honeycomb core made of fiber reinforced plastic. As appropriate, a resin is attached to and impregnated on the outer surface of the cell walls of the honeycomb core as a post-treatment.

Therefore, in the method of manufacturing a honeycomb core made of fiber reinforced plastic, first, when a prepreg sheet is formed into a corrugated sheet by a corrugating apparatus, the prepreg sheet is heated and pressed to form a corrugated sheet. Seepage,
Since the flowed resin is adsorbed to the resin adsorption sheet via the cross sheet, the resin does not adhere to the mold surface of the corrugating apparatus or the prepreg sheet does not adhere to the mold surface.
In addition, the resin adsorption sheet is provided with a release property from the corrugating apparatus, and the cross sheet is also provided with the release property on the corrugated sheet, and the resin adsorption sheet is replaced every time. The mold releasability does not deteriorate due to deterioration and does not peel off and adhere to the corrugated sheet side.

Second, when the prepreg sheet is formed into a corrugated sheet by a corrugating apparatus, the prepreg sheet to which the cross sheet is pressed and the outer surface of the corrugated sheet are roughened. Therefore, when stacking and joining corrugated sheets in the next process,
Since the bonding strength between the corrugated sheets is improved, the bonding strength between the cell walls of the manufactured fiber reinforced plastic honeycomb core is also improved, and the bonding strength is excellent. Third, since the outer surfaces of the corrugated plate and the cell wall are roughened in this way, when the resin is adhered and impregnated as a post-treatment, the resin is adhered and impregnated with excellent adhesion. Fourth, these are easily and easily realized by using a cloth sheet and a resin adsorption sheet. Moreover, the cross sheet can be used repeatedly, and the resin adsorption sheet is very inexpensive.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on embodiments of the invention shown in the drawings. FIG.
It is for description of Embodiment of this invention, and is an explanatory front sectional view to which the shaping | molding process of the corrugated sheet was expanded. FIG. 2 is an explanatory front sectional view in which a main part of a molded corrugated sheet is enlarged. FIG. 2A is a view showing a state in which a cross sheet and a resin adsorption sheet are provided in an embodiment of the present invention. The figure shows a state in which these are removed, and the figure (3) shows a conventional example of this type. FIG.
FIG. 1 is a front view for explaining a general example of this manufacturing method, and FIG. 1A is a diagram showing a prepared prepreg sheet,
FIG. 2B shows a corrugated sheet forming step, FIG. 3C shows a formed corrugated sheet, and FIG. 4D shows a step of laminating and joining corrugated sheets. FIG. 4 is a perspective view of the honeycomb core. FIG. 5 is a perspective view of a step of adhering and impregnating a resin as a post-treatment. FIG. 5A shows a state where the resin is immersed in a bathtub, and FIG. 5B shows a state after drying and curing.

First, with reference to FIG. 3, a method of manufacturing the honeycomb core 1 made of fiber-reinforced plastic according to the present invention and a method of manufacturing the honeycomb core 1 by a so-called corrugation method, which is a premise thereof, will be generally described. In this manufacturing method, first, as shown in FIG. 3A, a prepreg sheet 2 made of fiber reinforced plastic as a base material is prepared. Fiber reinforced plastics (FRP) include glass fiber, Kevlar fiber, carbon fiber, ceramic fiber,
Metal fibers, resin fibers, or other woven or non-woven fibers combined with epoxy resin, polyimide resin, other thermosetting resin or thermoplastic resin by adhesion, impregnation, mixing, etc. Become. The prepreg sheet 2 has a semi-cured state in which such a fiber-reinforced plastic is not yet completely cured, that is, a prepreg having flexibility and viscosity, and an extremely thin flat sheet.

Then, as shown in FIG. 3 (2),
The prepreg sheet 2 serving as the base material is supplied to a corrugating apparatus 5 such as a gear 3 (see FIG. 1) and a rack 4. The corrugating apparatus 5 is composed of a pair of upper and lower racks 4 in the example of FIG. 3 (2), and is composed of a pair of upper and lower gears 3 and a rack 4 in the example of FIG. 1 described later. It is also possible to use a belt type mold. Then, the prepreg sheet 2 is inserted between the gear 3 and the rack 4 of such a corrugating apparatus 5 and is sandwiched from both sides. By heating and pressurizing in this manner, the prepreg sheet 2 made of fiber reinforced plastic is
As shown in FIG. 3C, the corrugated plate 6 is formed into a corrugated sheet 6 made of fiber-reinforced plastic in which corrugations are continuously bent. The corrugated plate 6 has a trapezoidal shape as shown, and irregularities of substantially triangular, substantially square, and other various waveforms are linear and parallel in the short direction and continuously in the long direction, and have a predetermined pitch and height. It is made by bending.

Thereafter, the corrugated sheet 6 made of fiber-reinforced plastic thus formed is dried by applying a node bond, that is, an adhesive 7 to, for example, the lower surface and the upper surface of the valleys of the waves. Cut by length. Then, as shown in FIG. 3 (4), the plurality of corrugated sheets 6 are shifted vertically by a half pitch of the wave, and the valleys and the tops are aligned with each other between the upper and lower sides. Are stacked in a laminated block shape having a space as a whole. A flat plate (not shown) made of fiber-reinforced plastic similar to that described above may be further interposed between such corrugated plates 6. Thereafter, the corrugated sheets 6 stacked in this manner are heated and pressurized, whereby the resin is cured and the applied adhesive 7 is cured, and the corrugated sheets 6 are adhered to each other (as described above). If a flat plate is interposed, each corrugated plate 6 and the flat plate are also bonded.) In the illustrated example, the bonding method using the adhesive 7 is adopted, but the bonding method using the brazing material or the bonding using the melting and hardening of the resin constituting the corrugated sheet 6 by heating is used regardless of this. A method, etc. are also conceivable.

By following each of these steps, FIG.
The honeycomb core 1 made of fiber reinforced plastic shown in FIG. Now, in the method for manufacturing the honeycomb core 1 made of fiber-reinforced plastic according to the present invention, the following configuration is further added to the above-described manufacturing method.

That is, as shown in FIG. 1, in the manufacturing method of the present invention, the prepreg sheet 2 made of fiber reinforced plastic as a base material is separated from the cross sheet 8 having air permeability and subjected to the release processing. Resin adsorption sheet 9 with properties
After being sandwiched from both upper and lower sides, the corrugated sheet 6 is supplied to a corrugating apparatus 5 such as the gear 3 and heated and pressurized from both sides to form a corrugated sheet 6 whose outer surface is roughened. Then, after removing the cross sheet 8 and the resin adsorption sheet 9, a plurality of corrugated plates 6 are stacked and joined to manufacture the honeycomb core 1 made of fiber-reinforced plastic.

The cloth sheet 8 is made of a cloth that has been subjected to a release treatment by baking, adhering, or the like, a Teflon resin, a silicone resin, or another resin to a nylon cloth, a glass cloth, or another fiber base material. It consists of a shape material.
Thus, the cross sheet 8 is formed of a mesh type or a non-woven type having a large number of small openings and air permeability, and has a release property. The resin adsorption sheet 9 is made of glass cloth, paper, synthetic film, or the like.
It has mold release properties as well as resin adsorption properties. Then, the cloth sheet 8 is disposed inside the prepreg sheet 2 and the resin adsorption sheet 9 is disposed outside the prepreg sheet 2. The cross sheet 8 is superimposed on the prepreg sheet 2, and the resin adsorption sheet 9 is superposed via the cross sheet 8.

In this manufacturing method, in addition to the above, a configuration using such a cross sheet 8 and a resin adsorption sheet 9 is added, thereby manufacturing the honeycomb core 1 made of fiber reinforced plastic. This honeycomb core 1
As shown in FIG. 4, a hollow columnar shape partitioned and formed in an independent space is used as a cell wall 10 with a corrugated sheet 6 (furthermore, the above-mentioned flat plate) made of fiber reinforced plastic laminated and joined as described above. It is composed of a planar assembly of many cells 11.
The cross-sectional shape of the cell wall 10 and the cell 11 is typically a regular hexagonal shape as shown in the figure, but is not limited to this, and may be trapezoidal, substantially triangular, substantially square, or various other shapes. It is. The honeycomb core 1 made of fiber-reinforced plastic is excellent in weight ratio strength, is lightweight, has high rigidity and strength, and has a rectifying effect, flatness accuracy, heat insulation, and sound insulation, similarly to general ones. It has excellent properties such as high surface area per unit volume and is widely used as various structural materials.

When higher rigidity and strength are required for the honeycomb core 1 made of fiber-reinforced plastic, the outer surface of the cell wall 10 is reinforced as a post-treatment. Such post-processing will be described in more detail. When performing such post-processing,
The honeycomb core 1 made of fiber reinforced plastic manufactured as described above is first immersed in the bathtub 12 as shown in FIG. In the illustrated embodiment, a thermosetting resin 13 such as an epoxy resin or a phenolic resin in a solution state is stored in the bathtub 12 together with a solvent in the illustrated example. The stored thermoplastic resin may be stored. In the illustrated example, such a bathtub 1
2, a thermosetting resin 13 for reinforcement is attached to and impregnated on the outer surface of the cell wall 10 of the honeycomb core 1 made of fiber-reinforced plastic. Then, after the honeycomb core 1 made of fiber-reinforced plastic to which such adhesion and impregnation have been performed is taken out of the bathtub 12, the honeycomb core 1 is heated by a heater 14, radiant heat or the like as shown in FIG. The thermosetting resin 13 which has been dried and adhered and impregnated is cured, and is strongly bonded and fixed to the outer surface of the cell wall 10. Then, the rigidity and strength of the honeycomb core 1 made of fiber reinforced plastic are reinforced by the thermosetting resin 13 thus attached and impregnated.

The present invention has been described above. Then, it becomes as follows. In this manufacturing method, first, as shown in FIG. 1, a prepreg sheet 2 made of fiber-reinforced plastic as a base material is sandwiched between upper and lower sides by a double sheet 8 and a resin adsorption sheet 9, respectively. As shown in FIGS. (1), (2) and (3), the outer surface was roughened by supplying it to the corrugating device 5 such as the gear 3 and the rack 4 and applying heat and pressure. The corrugated sheet 6 is formed. Then, after the cross sheet 8 and the resin adsorption sheet 9 are removed, as shown in FIG. 3D, a plurality of corrugated sheets 6 are stacked and joined in a positional relationship where the valley portion and the top portion are aligned. By doing so, the honeycomb core 1 made of fiber reinforced plastic shown in FIG. 4 is obtained. Note that, as appropriate,
As shown in FIG. 5, a thermosetting resin 13 is attached and impregnated on the outer surface of the cell wall 10 formed by the corrugated plate 6 of the honeycomb core 1 as a post-treatment. Now, in the method of manufacturing the honeycomb core 1 made of fiber reinforced plastic, the following first, second, third, and fourth processes are performed.

First, when the prepreg sheet 2 is formed into a corrugated sheet 6 by the gear 3 or the rack 4 of the corrugating apparatus 5, the resin that has exuded and flowed out of the prepreg sheet 2 by heating and pressing is Cross sheet 8 with breathability
Is adsorbed on the resin adsorption sheet 9 side. As a result, the resin that has exuded and flowed adheres to the mold surface of the gear 3 and the rack 4 of the corrugating apparatus 5, and the prepreg sheet 2
Is reliably prevented from sticking to the mold surface,
Since the resin adsorption sheet 9 itself has releasability, the releasability of the corrugating device 5 from the gear 3, the rack 4, and the like after forming the corrugated sheet 6 is also ensured. Moreover, since the cross sheet 8 is subjected to a release treatment and has a releasing property to the prepreg sheet 2 and the corrugated plate 6, it is easily removed from the corrugated plate 6 afterwards, and the resin adsorption sheet 9 is replaced every time. System. Therefore, the cross sheet 8
The resin adsorbing sheet 9 is not scraped, worn, and deteriorated to reduce the releasability, and it is possible to prevent the resin adsorbing sheet 9 from peeling off and adhering to the prepreg sheet 2 and the corrugated sheet 6 side.

Secondly, when the prepreg sheet 2 is formed into a corrugated sheet 6 by the gear 3 or the rack 4 of the corrugating apparatus 5, the resin that has exuded and flowed out of the prepreg sheet 2 by heating and pressing is Cross sheet 8 with breathability
, The outer surfaces of the prepreg sheet 2 and the corrugated plate 6 against which the cross sheet 8 has been pressed are roughened without being mirror-finished. FIG. 2 is provided to explain such roughening of the surface A. When the cross sheet 8 and the like are removed as shown in FIGS. 1 and 2, the outer surfaces of the prepreg sheet 2 and the corrugated sheet 6 become rough. Surface A is formed. On the other hand, FIG. 2 (3) shows a corrugated sheet 15 of this type in the related art, the outer surface of which is mirror-finished. In other words, the resin that has exuded on the outer surface of the corrugated sheet 6 (that is, the exuded resin that has not been adsorbed on the resin adsorbing sheet 9) has its mirror surface B broken corresponding to the outer surface of the cross sheet 8 that has been pressed. Then, the corrugated sheet 6 is hardened in the presence of rough and fine irregularities, and the outer surface of the corrugated sheet 6 is roughened. Therefore, when the corrugated sheets 6 are stacked and joined in the next step, the outer surfaces roughened in this way are used, and the corrugated sheets 6 are securely bonded to each other with the adhesive 7, for example. The bonding strength between the corrugated sheets 6 is improved, and as a result, the bonding strength between the cell walls 10 of the manufactured fiber reinforced plastic honeycomb core 1 is improved, and the bonding strength is improved.

Third, since the outer surfaces of the corrugated sheet 6 and the cell wall 10 similarly formed are roughened, a thermosetting resin is used as a post-treatment for reinforcement as shown in FIG. 13
When adhering or impregnating, the thermosetting resin 13 and the like are adhered and impregnated on the cell wall 10 with excellent adhesion by using the roughened outer surface A. Thus, the honeycomb core made of the fiber reinforced plastic is excellent in the adhesion of the thermosetting resin 13 or the thermoplastic resin which is attached and impregnated as a post-treatment.

Fourthly, these prepreg sheets 2 made of fiber reinforced plastic as a base material are sandwiched between a cross sheet 8 and a resin adsorption sheet 9 and then supplied to a gear 3 and a rack 4 of a corrugating apparatus 5. This is easily and easily realized. Moreover, the cross sheet 8 can be used repeatedly, and the resin adsorption sheet 9 that is replaced every time is very inexpensive.

[0026]

As described above, the method for manufacturing a honeycomb core made of fiber reinforced plastic according to the present invention is such that a prepreg sheet is sandwiched from both sides by a cross sheet and a resin adsorption sheet to form a corrugated sheet. By doing so, the following effects are exhibited.

First, the releasability of the corrugating apparatus from gears and racks is ensured, and there is no fear of peeling off. That is, according to this manufacturing method, the resin in the prepreg sheet that has exuded and flowed is reliably prevented from adhering to the mold surface such as a gear or a rack of the corrugating apparatus,
The prepreg sheet is prevented from sticking to the mold surface.
That is, as in the above-described conventional example, the baked, adhered, and coated release agent and non-adhesive are removed,
Wear, deterioration, decrease in mold release, or peeling off and adhering to the prepreg sheet, that is, the corrugated sheet side,
Be avoided. Therefore, the quality of the corrugated sheet to be molded and the honeycomb core made of fiber-reinforced plastic to be produced are excellent.

Second, the bonding strength between the corrugated sheet and the cell wall is improved. That is, according to this manufacturing method, since the outer surfaces of the molded corrugated sheet and the cell wall are roughened, the mutual bonding force is improved, for example, the mutual bonding is surely performed by an adhesive. . Accordingly, the honeycomb core made of fiber reinforced plastic is superior in quality from this aspect as well, as compared with the above-described conventional example of this type, in which the bonding strength between the cell walls is excellent and the separation between the cell walls is difficult.

Third, the adhesiveness of the resin adhered and impregnated as a post-treatment is excellent. That is, according to this manufacturing method, since the outer surfaces of the molded corrugated sheet and the cell wall are roughened, the adhesiveness of the resin adhered and impregnated as a post-treatment for reinforcement is excellent. Therefore, the honeycomb core made of fiber-reinforced plastic is superior in quality in this aspect as compared with the above-mentioned conventional example, in that the adhesion, impregnation of the resin, cracks, cracks, cracks, peeling, etc. are less likely to occur. ing.

Fourth, they can be realized simply and easily and at an excellent cost. That is, this manufacturing method
By using the cross sheet and the resin adsorption sheet, the above-described first, second, and third points can be easily and easily realized. Moreover, the cross sheet can be used repeatedly,
The resin adsorption sheet is excellent in cost, such as being very inexpensive. As described above, the effects exhibited by the present invention are remarkable and large, for example, all the problems existing in this type of conventional example are solved.

[Brief description of the drawings]

FIG. 1 is an enlarged front cross-sectional explanatory view of a corrugated sheet forming process for a method of manufacturing a fiber reinforced plastic honeycomb core according to the present invention for describing an embodiment of the present invention.

FIG. 2 is an enlarged front cross-sectional explanatory view of a main part of a formed corrugated sheet, and FIG. 1A shows a state in which a cross sheet and a resin adsorption sheet are provided in an embodiment of the present invention; The figure shows a state in which these are removed, and the figure (3) shows a conventional example of this type.

FIG. 3 is an explanatory front view for explaining a general example of the manufacturing method, and FIG. 3 (1) shows a prepared prepreg sheet;
FIG. 2B shows a corrugated sheet forming step, FIG. 3C shows a formed corrugated sheet, and FIG. 4D shows a step of laminating and joining corrugated sheets.

FIG. 4 is a perspective view of a honeycomb core.

FIG. 5 is a perspective view of a step of adhering and impregnating a resin as a post-treatment, and FIG.
(2) The figure shows the dried and cured state after the fact.

[Description of Signs] 1 honeycomb core 2 prepreg sheet 3 gear 4 rack 5 corrugating device 6 corrugated sheet (of the present invention) 7 adhesive 8 cross sheet 9 resin adsorption sheet 10 cell wall 11 cell 12 bathtub 13 thermosetting resin 14 Heater 15 Corrugated plate (conventional example) A Rough surface B Mirror surface

Claims (2)

(57) [Claims] 1. A prepreg sheet made of a fiber reinforced plastic as a base material is made of a cross sheet that has air permeability and has been subjected to a mold release treatment, and a resin adsorption sheet having a mold release property.
Each is sandwiched from both sides, and then supplied to a corrugating device such as a gear or a rack, and heated and pressed from both sides, so that corrugated irregularities are continuously bent and the outer surface is roughened. After the formed corrugated sheet is formed, the cross sheet and the resin adsorption sheet are removed, and then the plurality of corrugated sheets are stacked and joined in a positional relationship where the valley portion and the top portion are aligned, thereby forming the corrugated sheet. A method for producing a honeycomb core made of fiber-reinforced plastic, comprising obtaining a honeycomb core, which is a planar assembly of hollow columnar cells, formed by partitioning a plate into cell walls. 2. The method for manufacturing a honeycomb core made of a fiber-reinforced plastic according to claim 1, wherein a resin is attached to and impregnated on an outer surface of a cell wall of the honeycomb core as a post-treatment. A method for manufacturing a honeycomb core made of fiber reinforced plastic.