JPH11147264A - Production of porous structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a lightweight porous structure having a three-dimensional structure and sufficient strength against vertical and lateral loads. SOLUTION: A porous structure producing method consists of a first process for winding reinforcing fibers 13 impregnated with an uncured resin 12 around the outer peripheral surfaces of spherical elements 11 comprising a biodegradable polymer to form a large number of reinforcing fiber spherical elements 14, a second process for packing a mold 16 with a large number of the reinforcing fiber spherical elements 14 in a crowded state and curing the uncured resin 12 to mutually bond the reinforcing fiber spherical elements 14, and a third process for introducing a biochemically active substance 19 into the spherical elements 11 composed of the biodegradable polymer to decompose the spherical elements 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a porous structure usable as a core material of a composite product reinforced with reinforcing fibers.

[0002]

2. Description of the Related Art In recent years, in response to demands for weight reduction and high strength, a prepreg made of a thermosetting resin such as an epoxy resin or an unsaturated polyester as a matrix and added with a reinforcing material such as carbon fiber, aramid fiber or glass fiber has been developed. Development is remarkable, and the needs of various products using these prepregs are increasing very much.

[0003] In addition, recently, there has been an increasing need for composite products using a thermoplastic resin such as nylon or polyetheretherketone (PEEK) as a matrix.

In particular, since this kind of prepreg is a material having excellent characteristics capable of manufacturing a lightweight and high-strength structural product, composite materials are large as various members used under extreme conditions in the aerospace field and the like. It is thought to exert power.

[0005] A honeycomb structure core used in a composite material structure is made of a thermosetting resin or a thermoplastic resin as a matrix, and long fibers of carbon fiber reinforced plastic (hereinafter, referred to as CFRP) or glass fiber reinforced plastic (hereinafter, referred to as CFRP) are used as reinforcing fibers. In the case of using GFRP), it has conventionally been necessary to laminate a prepreg on a trapezoidal mold having irregularities and to cure it by an autoclave or a press machine.

[0006]

However, it is known that if a long fiber CFRP or GFRP is used as a reinforcing fiber as a core material, a honeycomb plate having high strength and rigidity can be obtained. However, there is a problem that it takes time and effort to charge or laminate a mold in forming a corrugated sheet. In addition, since the honeycomb plate has a two-dimensional structure, it has high strength with respect to the load in the direction of the vertical plate forming the honeycomb plate, but the strength decreases with respect to the load in the direction perpendicular to the vertical plate. There's a problem.

When an aircraft wing is manufactured using a conventionally known honeycomb structure, as shown in FIG. 7, the body portion of the wing 1 has a density as low as possible, that is, a large cell size (a hexagonal shape). The length of one side of the honeycomb core 2 is longer), so that the weight of the wing 1 can be reduced. On the other hand, when it is desired to smooth the outer surface of the wing 1 or to increase the strength at the time of collision with an object to some extent, a honeycomb core having a high density, that is, a small cell size (a length of one side of a hexagon is short) is used. It is better to use 3.

For this reason, it has been attempted to form a two-layer structure through a prepreg 4 of a honeycomb core 2 having a large cell size and a honeycomb core 3 having a small cell size.
The production is troublesome, and it is difficult to produce a complicated three-dimensional curved surface, which is not practical. That is, the honeycomb core can be preformed at a high temperature, but a large heat-resistant type is required to perform the preform, which causes an increase in cost.

When manufacturing a three-dimensional curved surface using a honeycomb core, as shown in FIG. 8A, the core material 5 is cut from a rectangular block shape to a three-dimensional curved surface, or As shown in (b), the only choice is to use a honeycomb core material 6 for a three-dimensional curved surface, but all of them cause an increase in cost.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object a three-dimensional structure, which has sufficient strength against loads in vertical and lateral directions, and has a light weight. An object of the present invention is to provide a method for manufacturing a porous structure, which can easily manufacture a porous structure.

[0011]

According to the present invention, in order to achieve the above object, a first aspect of the present invention is to wind a reinforcing fiber impregnated with an uncured resin on an outer peripheral surface of a spherical body made of a biodegradable polymer. A first step of forming a large number of reinforcing fiber spheres, and filling the large number of reinforcing fiber spheres in a dense state inside a mold, curing the uncured resin, and forming the reinforcing fiber spheres. And a third step of introducing a biochemically active substance into a spherical body made of the biodegradable polymer to decompose the spherical body, the method comprising the steps of: .

[0012] The first step of winding a reinforcing fiber around an outer peripheral surface of a spherical body made of a biodegradable polymer to form a large number of reinforcing fiber spherical bodies, and a reinforcing fiber of the reinforcing fiber spherical body. A second step of applying an uncured resin or a molten resin to the mold, filling the large number of the reinforcing fiber spheres in a compact state in a molding die, curing the uncured resin, and allowing the reinforcing fiber spheres to contact each other. A method for producing a porous structure, comprising: a third step of bonding, and a fourth step of introducing a biochemically active substance into a sphere made of the biodegradable polymer to decompose the sphere.

[0013] The third step is that a prepreg is wound around an outer peripheral surface of a spherical body made of a biodegradable polymer and laminated to form a large number of spherical reinforcing fiber bodies; After the body is densely filled in the mold, the resin is heated to cure the resin in the prepreg, and the second step of bonding the reinforcing fiber spheres to each other is performed. And a third step of introducing and decomposing a biochemically active substance.

[0014] In a fourth aspect, a prepreg is wound around an outer peripheral surface of a spherical body made of a biodegradable polymer and laminated to form a large number of spherical reinforcing fiber bodies; After the body is densely filled into the mold, the resin in the prepreg is expanded by heating, and the reinforcing fiber spheres adjacent to each other have an irregular polyhedral shape so that the reinforcing fiber spheres are tightly bonded and hardened. And a third step of introducing a biochemically active substance into a sphere made of the biodegradable polymer to decompose the sphere.
And a method for producing a porous structure.

The spherical body is made of a biodegradable polymer, so that the spherical body is wound with a reinforcing fiber impregnated with an uncured resin, and the uncured resin is cured.
The spherical body can be decomposed by the action of a biochemically active substance such as an enzyme, and a porous structure composed of reinforcing fiber spheres can be formed.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a first embodiment,
A method for producing a container as a hollow structure will be described. FIG.
Numeral 11 in (a) denotes a hollow sphere, which is a biodegradable polymer, for example, a microbial biopol (trade name of Monsart Co.), the composition of which is a copolymer of hydroxybutyrate and valerate, or a chemically synthesized system. Is a polymer composed of aliphatic polyester, polyester of succinic acid and butanediol / ethylene glycol, etc., and decomposed by the action of biochemically active substances such as bacteria and enzymes. The spherical body 11 is formed by blow molding, injection molding or the like, and has an opening 11b in a part of the spherical body 11a. The spherical diameter of the spherical body 11a is several mm to several tens of mm, and it is preferable to use not only the same spherical diameter but also a mixture of spherical diameters different in size.

A resin layer of CFRP or GFRP is formed on the outer peripheral surface of the spherical body 11. As means for forming the resin layer, first, as shown in FIG.
A reinforcing fiber 13 made of carbon fiber or glass fiber impregnated with an uncured resin 12 such as an unsaturated polyester, epoxy resin, phenol resin or the like is almost uniformly pierced on the outer peripheral surface of the device 1 (if the winding is too tight, In order to make it difficult for biochemically active substances such as bacteria and enzymes to invade, it is wound around a coarse winding to form the reinforcing fiber spherical body 14 (first step).

Next, as shown in FIG.
a and a lower mold 15b, the cavity 17 of the molding die 16 is filled with the large number of the reinforcing fiber spheres 14 in a dense state, and the reinforcing fiber spheres 14 are cooled to room temperature or unheated resin 12
Is cured, the reinforcing fiber spheres 14 are integrally bonded together with the curing of the uncured resin 12 (second step). In this case, the reinforcing fiber spheres 14 having the same sphere diameter may be densely packed.
If 4a is arranged on the outer peripheral portion of the cavity 17 and the reinforcing fiber sphere 14b having a large sphere diameter is arranged in the center of the cavity 17, the reinforcing fiber sphere 14 has a high density in the outer layer and a low density in the inner layer.

Thus, a large number of reinforcing fiber spheres 14
After the spherical aggregate 18 made of
The sphere aggregate 18 is taken out from the container and placed in a tank 20 containing a biochemically active substance 19 such as bacteria and enzymes, specifically muddy water containing microorganisms, as shown in FIG. When the biochemically active substance 19 is immersed and left for several days to several weeks, the biochemically active substance 19 penetrates the reinforcing fiber spheres 14 and is introduced into the spheres 11 made of biodegradable polymer inside, and The body 11 is decomposed (mainly carbon dioxide and water) (third step).

After the spherical body 11 has been decomposed, the residue is discharged, and as shown in FIG.
A porous structure 21 made of resin 3 and resin is obtained. By using this as a core material and applying a surface plate 22 to the surface layer, an aircraft wing or the like made of a composite material can be formed.

FIG. 2 shows the second embodiment, which differs from the first embodiment in the method of forming the resin layer. That is, FIG.
As shown in (a), a reinforcing fiber 13 made of carbon fiber or glass fiber is provided on a spherical body 11 made of biodegradable polymer.
Is wound so that the eyes can be seen almost uniformly (the first step),
A catalyst is added to the reinforcing fibers 13, and then, as shown in FIG. 4B, an uncured resin such as unsaturated polyester, epoxy resin,
3 (second step). As a means for adding the molten resin 23, the uncured resin or the molten resin 23 contained in the tray 24 may be adhered to the roller 25 and applied on the reinforcing fiber 13. It may be immersed together with the spherical body 11. Note that the third step is the same as in the first embodiment.

FIG. 3 shows a third embodiment, which differs from the first and second embodiments in the method of forming the resin layer. That is, as shown in FIG. 3A, the prepreg 26 is wound around the outer peripheral surface of the spherical body 11 made of a biodegradable polymer (first step), and then, as shown in FIG. 2
6, the spherical body 11 around which a large number of reinforcing fiber spheres 27 are densely filled in the cavity 17 of the molding die 16 composed of the upper die 15a and the lower die 15b.
7 is heated to cure the resin in the prepreg 26,
The reinforcing fiber spheres 27 are integrally bonded together with the curing of the resin (second step). Note that the third step is the same as in the first embodiment.

FIG. 4 shows a fourth embodiment, in which first to third embodiments are shown.
The method of heating and curing the reinforcing fiber spherical body 27 is different from that of the embodiment. That is, as shown in FIG. 4A, after the prepreg 26 is wound around the outer peripheral surface of the spherical body 11 made of the biodegradable polymer (first step), as shown in FIG.
When the spherical body 11 around which the prepreg 26 is wound, that is, a large number of reinforcing fiber spherical bodies 27 are densely filled in the cavity 17 of the molding die 16 including the upper mold 15a and the lower mold 15b, and the reinforcing fiber spherical bodies 27 are heated, The resin in the prepreg 26 expands, and consequently, the adjacent reinforcing fiber spheres 27 press against each other to fill the gap, and the reinforcing fiber sphere 27 has a cross section of 6 mm.
It becomes a polygon such as a square or an octagon, becomes an irregular polyhedral shape, and cures, and the reinforcing fiber spheres 27 are integrally joined together with the curing of the resin (second step). Note that the third step is the same as in the first embodiment.

When the reinforcing fiber spheres 27 filled in the cavity 17 of the molding die 16 in a dense state are heated and simultaneously vacuum-evacuated from around the molding die 16, the thermal expansion of the resin can be promoted. There is an effect that the degree of adhesion between the spherical bodies 27 increases. In addition, the spherical body 11 has a hollow structure, and air or a volatile liquid or the like is previously sealed therein, so that these fluids expand during heating, and as a result, the expansion of the spherical body 11 is assisted or the internal pressure is reduced. By increasing the effect, the degree of adhesion between the reinforcing fiber spheres 27 can be increased.

FIG. 5 shows a fifth embodiment, in which, in addition to the method of manufacturing a hollow structure according to the first embodiment, another reinforcing member 28 is added to the most necessary part in terms of strength. By setting the reinforcing material 28 in the cavity 17 when filling the reinforcing fiber spherical body 14 into the cavity 17 of the mold 16, a hollow structure excellent in strength can be manufactured.

FIG. 6 shows a sixth embodiment. In addition to the method of manufacturing a hollow structure according to the first embodiment, when manufacturing a hollow structure having excellent heat insulating properties, a large number of, for example, spherical heat insulating materials 29 are used.
a to form a heat insulating layer 29. In this case, a reinforcing fiber layer is formed around the spherical heat insulating material 29a by the same method as that applied around the spherical body 11.

When the cavity 17 of the molding die 16 is filled with the reinforcing fiber spheres 14, the cavity 17 is filled with a large number of spherical insulating materials 29a, and then heated to heat the reinforcing fiber spheres 14 and the spherical insulating material 29a. By combining the material 29a, a hollow structure having excellent heat insulating properties can be manufactured. Here, the case where the heat insulating material is inserted has been described. However, when it is desired to provide the structure with sound absorbing properties or sound insulating properties, the sound absorbing material processed into a sphere is used in place of the spherical heat insulating material 29a, and the same as described above. By using a simple method, a structure using a porous structure excellent in sound absorption characteristics can be obtained.

When a heat insulating layer is formed from a conventional honeycomb sandwich plate, since the honeycomb core has no partition in the thickness direction, when the heat insulating material is filled, the heat insulating material enters the entire thickness direction and is separated. Although the heat insulating layer cannot be formed, the heat insulating layer having an arbitrary thickness can be formed according to the purpose of use by adopting the sixth embodiment.

In each of the above embodiments, the spherical body is formed by blow molding, injection molding, or the like, and a true spherical spherical body is used. The attached cube and cross section may be elliptical.

Furthermore, in each of the above embodiments, a method of manufacturing a composite molded article having an independent spherical hollow portion and a core material of an aircraft wing has been described. However, the present invention is not limited to the above embodiments. Instead, the present invention can be applied to the manufacture of ship structures, architectural structures, works of art, and the like.

[0031]

As described above, according to the present invention, by forming a sphere with a biodegradable polymer, the sphere can be decomposed by the action of biochemically active substances such as bacteria and enzymes. Thus, a porous structure made of reinforcing fiber spheres can be formed. Therefore, there is an effect that a lightweight porous structure having a three-dimensional structure, having sufficient strength against loads in the vertical direction and the lateral direction, and being lightweight can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a method for manufacturing a porous structure according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing a method for manufacturing a porous structure according to a second embodiment of the present invention.

FIG. 3 is an explanatory view showing a method for manufacturing a porous structure according to a third embodiment of the present invention.

FIG. 4 is an explanatory view showing a method for manufacturing a porous structure according to a fourth embodiment of the present invention.

FIG. 5 is an explanatory view showing a method for manufacturing a porous structure according to a fifth embodiment of the present invention.

FIG. 6 is an explanatory view showing a method for manufacturing a porous structure according to a sixth embodiment of the present invention.

FIG. 7 is a longitudinal side view showing a conventional honeycomb core.

FIG. 8 is an explanatory diagram in the case of manufacturing a three-dimensional curved surface using a conventional honeycomb core.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Spherical body 12 ... Uncured resin 13 ... Reinforcing fiber 14 ... Reinforcing fiber spherical body 16 ... Molding mold 19 ... Biochemical active substance

──────────────────────────────────────────────────の Continued on front page (51) Int.Cl. ⁶ Identification code FI B29K 105: 06

Claims (4)

[Claims] 1. a first step of winding a reinforcing fiber impregnated with an uncured resin on the outer peripheral surface of a spherical body made of a biodegradable polymer to form a large number of reinforcing fiber spherical bodies; A second step in which the fiber spheres are densely packed in a molding die, the uncured resin is cured, and the reinforcing fiber spheres are bonded to each other; A third step of introducing and decomposing an active substance, and a method for producing a porous structure. 2. A first step in which reinforcing fibers are wound around an outer peripheral surface of a spherical body made of a biodegradable polymer to form a large number of reinforcing fiber spherical bodies, and the reinforcing fibers of the reinforcing fiber spherical bodies are uncured. A second step of applying a resin or a molten resin; and filling the plurality of reinforcing fiber spheres in a compact state in a molding die, curing the uncured resin, and bonding the reinforcing fiber spheres to each other. 3. A method for producing a porous structure, comprising: a third step; and a fourth step of introducing a biochemically active substance into a sphere made of the biodegradable polymer to decompose the sphere. 3. A first step of winding and laminating a prepreg around an outer peripheral surface of a spherical body made of a biodegradable polymer to form a large number of reinforcing fiber spherical bodies, and forming the large number of reinforcing fiber spherical bodies. A second step of heating the resin in the prepreg to cure the resin in the prepreg and bonding the reinforcing fiber spheres to each other; 3. A method for producing a porous structure, comprising: a third step of introducing and decomposing a substance. 4. A first step of winding and laminating a prepreg on an outer peripheral surface of a spherical body made of a biodegradable polymer to form a large number of reinforcing fiber spherical bodies, and forming the large number of reinforcing fiber spherical bodies. After filling the mold in a dense state, heat it to expand the resin in the prepreg,
A second step in which adjacent reinforcing fiber spheres are tightly bonded and hardened to each other in an irregular polyhedral shape; and a step of introducing a biochemically active substance into the sphere made of the biodegradable polymer to decompose. 3. A method for producing a porous structure, comprising the steps of: