JPH07214710A - Honeycomb core and manufacture thereof - Google Patents

Abstract

PURPOSE:To prevent a deformation and displacement of a cell wall or a cell from being caused, by a method wherein the basic material of a cell wall forming a cell is a prepreg sheet of fiber-reinforced plastic for which polyimide resin is used mostly, the sheets are comprised by performing pilling, stripe line adhesion and extension and the stripe line adhesion between the cell walls is performed by a low temperature curing adhesive. CONSTITUTION:Low temperature curing adhesive A curing at a lower temperature than those of a mold release agent 2 and polyimide resin is applied to the surface of a prepreg sheet 1 of fiber-reinforced plastic of the basic material of a cell wall for which polyimide resin is used mostly in a specific direction, width and pitch and stripe line state alternately. A large number of the sheets are piled up while sliding to the right and left on every other sheet so that after the same is cut off in every specific length, the adhesive A in a state of a stripe line becomes a positional relation where the adhesives A are slid respectively vertically half pitch by half pitch. Only the low temperature curing A is allowed to melt and cure by performing low temperature heating and processing and after performance of stripe line adhesion between the prepreg sheets 1 each, they are made into a blocklike state by cutting into necessary widths, extended in a pilling direction by tensile strength and a honeycomb core of planar aggregate of a hollow columnar cell is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a honeycomb core and a method for manufacturing the same. That is, the present invention mainly relates to a honeycomb core using a fiber reinforced plastic prepreg sheet using a polyimide resin as a base material, and a manufacturing method thereof.

[0002]

2. Description of the Related Art This type of honeycomb core is known to have excellent heat resistance, but it has generally been manufactured by the following steps. That is, a fiber reinforced plastic prepreg sheet, which is a base material mainly made of polyimide resin, is continuously bent into a corrugated plate by heating and pressing with a gear or a rack, and then this corrugated plate is fixed. In addition to cutting for each dimension, stacking it in a laminated block shape while aligning the valley and the top with the adhesive applied in a striped shape,
Then, the honeycomb core was manufactured by heating and pressurizing at the melting point temperature of the adhesive thus stretched in a linear manner to bond between the corrugated plates. That is, by following these steps, a fiber reinforced plastic prepreg sheet mainly made of a polyimide resin is used as a base material, and the corrugated plate forms a cell wall, and the cell wall partitions each into an independent space. A honeycomb core, which is a planar aggregate of hollow columnar cells, has been manufactured.

[0003]

By the way, the following problems have been pointed out in such a conventional example. First
In the process of heating and pressurizing at the melting point temperature of the adhesive that has been overlaid with the stacked corrugated sheets to perform striation bonding, the corrugated sheets stacked by bending the prepreg sheet are When sandwiched from above and below and pressed, it was easy to deform and displace due to the pressure. As a result, the cell walls and cells formed by the corrugated sheet are deformed and displaced, resulting in unevenness, irregular alignment, misalignment, crushing, breakage, etc. Especially, the position of the adhesive line that is glued is incorrect. So, so-called misalignment occurs,
There were major problems in the accuracy and quality of the honeycomb core.

Secondly, as a method for manufacturing a honeycomb core, there is generally a spreading method in addition to the so-called corrugation method described above. However, since the spreading method involves stacking, striking and spreading the base materials, The following problems have been pointed out when a fiber-reinforced plastic prepreg sheet mainly using a polyimide resin is used as a base material. That is, in the process of melt-curing the adhesive to bond the striations, the prepreg sheet is likely to be hardened by heating and pressure, and the flexibility of the prepreg sheet is reduced and the rigidity is high, which may hinder the spreading process. There were many. In addition, in order to solve such problems, it is necessary to develop a dedicated production line and equipment, and it takes a lot of time and labor.The conventional spreading method has a manufacturing cost in the case of using a prepreg sheet as a base material. There were many difficulties and problems.

In view of the above situation, the present invention has been made to solve the problems of the above-mentioned conventional examples, and mainly uses a prepreg sheet of fiber reinforced plastic using a polyimide resin for stacking and stripping. By adopting a spreading method of wire bonding and spreading, and by using a low temperature curing adhesive to perform striation bonding, firstly, deformation of cell walls and cells,
Secondly, it is an object of the present invention to propose a honeycomb core made of a fiber-reinforced plastic mainly using a polyimide resin, which is excellent in manufacturing cost in addition to preventing displacement, and a manufacturing method thereof.

[0006]

The technical means of the present invention for achieving this object are as follows. First, the claim 1 is as follows. That is, this honeycomb core is
A planar aggregate of hollow columnar cells, a prepreg sheet of a fiber reinforced plastic mainly using a polyimide resin is used as a base material of a cell wall forming the cell, and the prepreg sheets are stacked, Striations are adhered and stretched, and the cell walls are adhered to each other by a low temperature curable adhesive that cures at a lower temperature than the polyimide resin of the prepreg sheet.

The second aspect of the present invention is as follows. That is, in this method for manufacturing a honeycomb core, first, on the surface of a fiber-reinforced plastic prepreg sheet mainly made of a polyimide resin, which is a base material, is cured at a constant direction, width, and pitch at a temperature lower than that of the polyimide resin. A low-temperature curable adhesive is attached in a strip shape, and then the prepreg sheets are vertically stacked in a positional relationship in which the strip-shaped adhesive is displaced by half a pitch. Then, the low-temperature curing adhesive is melt-cured by low-temperature heating and pressurization to bond the prepreg sheets with striations, and then stretched by applying tensile force in the stacking direction and then by high-temperature heating. The prepreg sheet is completely cured to obtain a honeycomb core which is a planar aggregate of hollow columnar cells.

[0008]

Since the present invention comprises such means, it operates as follows. In the present invention, the fiber-reinforced plastic prepreg sheet mainly using a polyimide resin,
After applying a low temperature curing adhesive in the form of striations and stacking them, the striations are adhered by low temperature heating and pressure and spread in the stacking direction.
It is completely cured by heating at high temperature.

Therefore, firstly, the prepreg sheet is
First, the sheets are stacked in a flat sheet state, adhered to the striations by low temperature heating and pressure, and then bent by expansion and heated at high temperature. In this way, since the pressure is not applied after being stretched and bent, the deformation and displacement of the cell walls and cells are prevented. Secondly, by separating the bonding of the prepreg sheet by the low temperature heating of the low temperature curing type adhesive and the complete curing of the prepreg sheet by the high temperature heating, the spreading can be performed smoothly, and the prepreg sheet is used as the base material. ,
Other production lines and equipment using aluminum or aramid base materials can be used as they are, and there is no need for time-consuming production. In this way, the manufacturing process is simplified, and this type of honeycomb core is easily and easily manufactured.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the embodiments shown in the drawings. 1 and 2 are perspective views, and FIGS. 3 and 4 are front explanatory views. Then, FIG. 1 (1) shows the step of applying the adhesive, and FIG. 1 (2) shows the step of stacking and then low-temperature heating and pressurizing to perform striation bonding. The drawing shows the cutting step, and the drawing (2) of FIG. 2 shows the spreading step. FIG. 3 shows a complete curing step, FIG. 4 (1) shows an impregnating agent dipping step, and FIG. 4 (2) shows a drying / curing step.

In this manufacturing method, first, as shown in FIG. 1 (1), the surface of a fiber reinforced plastic prepreg sheet 1 which is a base material mainly using a polyimide resin,
The release agent 2 and the low-temperature curable adhesive A that cures at a temperature lower than that of the polyimide resin are alternately applied in a line shape in a constant direction, width, and pitch.

More specifically, as the fiber reinforced plastic (FRP), glass fibers, Kevlar fibers, carbon fibers, and other base fibers which are mainly combined with a polyimide resin by adhesion or impregnation are used. . The fiber-reinforced plastic prepreg sheet 1 mainly using a polyimide resin is softened by heating to have viscosity and is in a semi-cured state, and also has an extremely thin and flat belt-like sheet shape. As the release agent 2, for example, fluororesin, polyester resin, polyethylene resin, other resin or metal having non-viscosity and releasability is used, and those in sheet form, synthetic film form, etc. are appropriately selected. used. Then, such a release agent 2 is used as the prepreg sheet 1.
In the illustrated example, in the illustrated example, the wide width and the pitch are sequentially arranged in the short-side direction, and the low temperature curable adhesive A is, for example, applied to the roll 3 in a narrow space between the release agents 2. By being applied and dried, it is attached in a strip shape with a narrow width and pitch. As such a low temperature curable adhesive A, a substance that melts and cures at a lower temperature than the polyimide resin of the prepreg sheet 1 is used, and for example, a two-component epoxy adhesive having particularly excellent adhesive strength or heat resistance is particularly preferable. An excellent low temperature curing type polyimide adhesive is used.

In this manufacturing method, next, as shown in FIG. 1 (2), such a prepreg sheet 1 is piled up in a positional relationship in which the linear adhesive A is displaced by half a pitch. . That is, the prepreg sheet 1 to which the adhesive A is applied in the form of a strip through the release agent 2 as described above is cut at a constant length, and then the strip of the adhesive A is placed on each of the upper and lower sides by a half pitch. A large number of sheets are piled up in a block shape while being shifted left and right every other sheet so that the positional relationship is shifted.

Then, in this manufacturing method, as shown in FIG. 1 (2), only the low-temperature curable adhesive A is heated and pressed at low temperature to be melt-cured, and the prepreg sheets 1 stacked on top of each other. Strike the space between them. That is, the prepreg sheets 1 stacked in blocks while interposing the low temperature curable adhesive A and the release agent 2 as described above do not completely cure the polyimide resin in a furnace (not shown) or the like. At the same time, the low temperature curable adhesive A is pressed while being heated at the temperature and time for curing, whereby the curing is slightly advanced and the viscosity is lowered, and the adhesive has a considerably flexible state. In this way, the prepreg sheets 1 that are stacked one above the other are striation-bonded by the melt curing of the low-temperature curable adhesive A, and are separated from each other at locations other than the low-temperature curable adhesive A. It is separated by the mold agent 2 and adhered to the line to the extent necessary for the expansion in the next step, and has the flexibility required for the expansion.

Next, in this manufacturing method, as shown in FIG. 2 (1), the prepreg sheets 1 stacked as described above and adhered to each other by the striations are cut by a cutter 4 as necessary, and necessary. The width is block-shaped. Thereafter, in this manufacturing method, as shown in FIG. 2B, a tensile force is applied in the stacking direction to carry out expansion. That is, the prepreg sheet 1 in the form of a block, which is laminated and adhered to the line as described above, is formed.
Is stretched by applying a tensile force with the stacking direction as the stretching direction in a room temperature environment.At that time, if it is difficult to stretch due to high rigidity and lack of flexibility, heat it for a short time. Implement the extension. In this way, the honeycomb core 6, which is a planar aggregate of the hollow columnar cells 5, is formed and held in that shape.

In this manufacturing method, as shown in FIG. 3, the honeycomb core 6 thus formed is completely hardened by heating at high temperature. That is, the honeycomb core 6 stretch-formed and shape-maintained as described above is heated at a higher temperature in the furnace 7 by the heat source 8 at a higher temperature than that at the time of the above-described striation bonding, as a post-process, and thus the polyimide resin is mainly used. The cell wall 9 having the fiber reinforced plastic prepreg sheet 1 as a base material is finally completely cured to have predetermined rigidity and strength as a whole. The release agent 2 is appropriately removed if necessary.

By following these steps, the honeycomb core 6 is manufactured. That is, the honeycomb core 6 made of a fiber-reinforced plastic mainly using a polyimide resin is a planar aggregate of the hollow columnar cells 5 partitioned into independent spaces, and the cell walls 9 forming the cells 5 are formed. As a base material, a prepreg sheet 1 of a fiber-reinforced plastic mainly using a polyimide resin is used, and the prepreg sheets 1 are stacked, strut-bonded, and spread. Striation-bonded with a low temperature curing type adhesive A that cures at a lower temperature than the polyimide resin. In addition to the hexagonal shape shown in the drawing, the cells 5 and the cell walls 9 have triangular, quadrangular,
Trapezoids and other various shapes are possible. The honeycomb core 6 is generally excellent in weight ratio strength, is lightweight, has high rigidity and strength, is excellent in rectifying effect, plane accuracy, heat retention, and sound insulation, and has a surface area per unit volume. The characteristics of being large, etc. are known. Further, since the honeycomb core 6 is mainly made of a fiber reinforced plastic using a polyimide resin, it is particularly excellent in heat resistance and strength in weight ratio.

If higher rigidity, strength and weight are required for the manufactured honeycomb core 6,
Further, the following process is additionally performed as a post-treatment. That is, in this case, the honeycomb core 6 has a structure (1) in FIG.
As shown in the figure, it is immersed in a solution of an impregnating agent 10 in a bath 11 made of a polymer-binding substance such as phenol resin, and the prepreg sheet 1 is used as a base material for the cell wall 9 as described above.
The reinforcing impregnating agent 10 is attached and impregnated. Then, as shown in FIG. 4B, the honeycomb core 6 thus impregnated with and impregnated with the impregnating agent 10 is taken out of the bath 11 and then heated by the heat source 13 in the processing chamber 12. , And is dried, so that the impregnating agent 10 is cured with the surface of the cell wall 9 being coated. Further, when the release agent 2 interferes with such adhesion and impregnation of the impregnating agent 10, it is appropriately removed. In addition, such adhesion and impregnation of the reinforcing impregnating agent 10 may be repeatedly performed until the honeycomb core 6 reaches the required rigidity, strength, and weight.

The present invention is as described above. Then it becomes as follows. In the present invention, first, as shown in FIGS. 1 (1) and 2 (2) of the fiber-reinforced plastic prepreg sheet 1 mainly using a polyimide resin, the low temperature curable adhesive A has a linear shape. Applied to the
Stacked. Then, as shown in FIGS. 2 (1) and 2 (2), after being appropriately cut, the low-temperature curing adhesive A is melt-cured by low-temperature heating and pressure to be striation-bonded and stacked. Direction, a tensile force is applied to the honeycomb core 6 and the honeycomb core 6 is completely cured by heating at a high temperature as shown in FIG.
It is said that Therefore, according to the honeycomb core 6 and the manufacturing method thereof, the following first and second aspects are obtained.

First, the fiber-reinforced plastic prepreg sheet 1 mainly made of polyimide resin is first bent into corrugated sheets and then stacked as in the corrugated conventional prepreg sheet 1 of this kind. Instead of being adhered by heating and pressurizing, the sheets are first stacked in the sheet state by the spreading method, and are bonded by striations by heating and pressing, and then bent by stretching and heated at high temperature. As described above, first, the sheets are stacked and pressed in a flat sheet state, and then expanded and bent, and no pressure is applied after bending by expansion, so that the cell walls 9 and the cells 5 are not deformed or displaced. Certainly prevented.

Secondly, the bonding of the prepreg sheet 1 by the low temperature heating of the low temperature curable adhesive A and the prepreg sheet 1
Since the prepreg sheet 1 is separated from the complete curing by high temperature heating, the prepreg sheet 1 can be smoothly stretched while having flexibility. Further, although the prepreg sheet 1 is used as a base material, other expansion type production lines and equipment using an aluminum or aramid base material can be used as they are by changing only the heating temperature. As described above, as compared with the above-described conventional example of the spreading method, a dedicated manufacturing line / equipment is not required and the manufacturing process is simplified, the manufacturing process is simplified, and the honeycomb core 6 is easily and easily manufactured. It

[0022]

As described above, the honeycomb core and the method for manufacturing the same according to the present invention employ the expansion method in which the fiber reinforced plastic prepreg sheet mainly using the polyimide resin is piled up, striation-bonded and expanded. The following effects are exhibited by adopting it and by adopting low-temperature curing type adhesive to perform striation bonding.

First, the deformation and displacement of the cell walls and cells are prevented. That is, in the honeycomb core made of a fiber-reinforced plastic mainly using a polyimide resin, the unevenness of the cell walls or cells, the disorder of the arrangement, the shift, the crushing, which have been pointed out in the above-mentioned conventional example of this kind, Breakage is resolved,
In particular, the striation bonding position is accurate and so-called misalignment does not occur. Thus, a honeycomb core excellent in accuracy and quality can be obtained.

Second, the manufacturing process is simplified and the manufacturing cost is excellent. In other words, the expansion can be performed smoothly, and although the prepreg sheet is used as the base material, the production line / equipment using other base materials of aluminum or aramid can be used as it is, and it does not particularly take time to manufacture. Can be easily and easily manufactured, and is excellent in manufacturing cost. As described above, the effects of the present invention are remarkably large, such as the problems existing in this type of conventional example are eliminated.

[Brief description of drawings]

FIG. 1 is a perspective view for explaining an embodiment of a honeycomb core and a method for manufacturing the same according to the present invention. (1) is an adhesive application step, and (2) is a low temperature after stacking. The process of heating and pressing to bond the striations is shown.

FIG. 2 is a perspective view for explaining the embodiment, (1)
The figure shows the cutting step, and the figure (2) shows the spreading step.

FIG. 3 is a front explanatory view for explaining the embodiment, showing a complete curing step.

FIG. 4 is a front explanatory view for explaining the embodiment,
(1) is the impregnating agent soaking process, (2) is the drying process.
A hardening process is shown.

[Explanation of symbols]

 1 Prepreg Sheet 2 Release Agent 3 Roll 4 Cutter 5 Cell 6 Honeycomb Core 7 Furnace 8 Heat Source 9 Cell Wall 10 Impregnating Agent 11 Bathtub 12 Processing Room 13 Heat Source A Low Temperature Curing Adhesive

Claims (2)

[Claims] 1. A planar aggregate of hollow columnar cells, wherein a prepreg sheet of fiber reinforced plastic mainly using a polyimide resin is used as a base material of a cell wall forming the cell, and the prepreg is also used. Stacking sheets,
A honeycomb core characterized in that it is formed by striation bonding and spreading, and the cell walls are striation-bonded by a low-temperature curable adhesive that cures at a lower temperature than the polyimide resin of the prepreg sheet. 2. A low temperature curable adhesive which is hardened at a temperature lower than that of the polyimide resin in a fixed direction, width and pitch on the surface of a prepreg sheet of a fiber reinforced plastic using a polyimide resin as a base material. Is attached to the line,
Next, the prepreg sheets are stacked one above the other in a positional relationship in which the strip-shaped adhesive is displaced by half a pitch, and the low-temperature curable adhesive is melt-cured by low-temperature heating and pressurization. Strut-bonding between prepreg sheets, and after that,
After stretching by applying a tensile force in the stacking direction, the prepreg sheet is completely cured by heating at high temperature to obtain a honeycomb core which is a planar aggregate of hollow columnar cells.
A method for manufacturing a honeycomb core, comprising: