JPH07125118A - Material with sandwich structure - Google Patents

Abstract

PURPOSE:To provide material with a sandwich structure which is light weight and has a good penetration resistance and a burn through property. CONSTITUTION:In material with a sandwich structure which is made by laminating fiber reinforced resin plates 2 comprising reinforcing fibers and matrix resin on both sides of a core material 1, carbon fibers having a tensile elastic modulus of 20X10<3>kgf/mm<2> or more and breaking distortion energy of 4.0 mm.kgf/mm<3> or more are used as the reinforcing fibers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sandwich structural material, and more particularly to a sandwich structural material suitable as a structural material such as an aircraft flooring material or an interior material.

[0002]

2. Description of the Related Art In the field of flying objects such as artificial satellites and aircraft, the energy saving effect based on the weight reduction of those structural materials is remarkable. Particularly in the case of commercial aircraft, since the number of flights is large and the flight distance is long, it is pursued to save fuel consumption by reducing the weight of the structural material.

Among the structural materials for aircraft, flooring materials and interior materials are used over the entire surface of the aircraft, and the area used is considerably large and the weight used is considerably heavy. Conventionally, as a structural material such as the above-mentioned floor material and interior material, for example, a sandwich structural material in which a honeycomb structure is used as a core material and glass fiber reinforced resin plates are adhered to both surfaces thereof as skin materials has been mainly used. It was

In the case of this sandwich structure material, especially when it is used as a floor material, it is required to have excellent properties such as bending strength, bending rigidity, penetration resistance and burn-through property. Particularly, from the viewpoint of ensuring aircraft safety, it is necessary to have excellent penetration resistance and burn-through properties. For example, when a sandwich structure material having poor penetration resistance is used as a floor material, the following accident may occur.

That is, in a commercial aircraft flying in the high altitude, the passenger compartment is in a pressurized state as a precompression chamber, and the cargo compartment located in the lower part of the passenger compartment is not in a pressurized state, so that the penetration resistance is very excellent. If the floor material is not open, and if there is a hole in the skin due to a sharp member such as the heel of a woman's high heel, the skin on the cargo side will peel off from the core due to the pressure on the passenger side. , Destruction of the floor material will proceed.
Then, as the floor material is destroyed, the air in the passenger compartment flows into the cargo compartment with a sudden force, the girder material supporting the floor is also destroyed, and the function of the entire aircraft may stop. is there.

[0006] Burn-through means the interior of an aircraft.
Or floor materials and interior materials are
Exhibits the property of blocking the flame and suppressing its spread for a fixed time
It is a characteristic and is usually judged by the size of the cover factor.
ing. Here, the cover factor is a skin material.
Area S in fiber reinforced resin plate ₁When the area of is set
And the area S₁And the reinforcing fiber material present in the area
Area S occupied by the outer part₂From the following equation: Cf (%) = [(S₁-S₂) / S₁] It refers to a value calculated based on 100.

For example, when the reinforcing fiber material is a woven fabric of warp and weft yarns, the total value of the voids formed at the intersections of the warp yarns and weft yarns, that is, the areas of the perforations, in the region S ₁ is It becomes the above-mentioned area S ₂ . When the Cf value increases, the voids in the reinforcing fiber material decrease, so that the skin material has higher resistance to blowout of the flame and the burn-through property is improved. In the case of a skin material having a small Cf value, since the voids are large and blown through the flame easily from the voids, the burn-through property is low.

In the case of a conventional sandwich structure material using a glass fiber reinforced resin plate as a skin material, the melting point of the glass fiber is low, and for example, when the skin material comes into contact with flame, the glass fiber is melted in a short time, so that the burn-through property is low. It is poor. Further, since the specific gravity of glass fiber is as large as about 2.56 and the elastic modulus is small, it is necessary to increase the thickness of the skin material in order to satisfy the predetermined rigidity when the sandwich structure material is actually used. Become. However, when increasing the thickness of the skin material, it is necessary to increase the amount of glass fiber used, and as a result, the entire skin material becomes heavy.

By the way, recently, in order to reduce the weight of a sandwich structure material used as a floor material or an interior material, a carbon fiber woven fabric has been used as a reinforcing fiber material of a fiber reinforced resin plate which is a skin material. It is being appreciated. In that case, in order to improve the burn-through property of the skin material, that is, in order to increase the Cf value of the carbon fiber woven fabric and the strength of the fiber reinforced resin plate, the carbon fiber woven fabric is usually
A high density woven fine carbon fiber yarn is used.

In the case of this skin material, the carbon fiber has a specific gravity of about 1.75 and is lighter than the above-mentioned glass fiber. Since mechanical properties such as bending strength and bending rigidity can sufficiently satisfy the properties required as a skin material, considering only the relationship with this mechanical property, the thickness of the skin material should be reduced. Is not inconvenient. However, from the viewpoint of ensuring penetration resistance, the skin material cannot be made too thin. Therefore, as a result, the thickness of the skin material is unavoidably increased, and a remarkable weight reduction has not been achieved.

When a flame is applied to the surface material, the flame blows out, though slightly, from the portion where the carbon fiber does not exist but only the matrix resin exists, that is, the hollow portion. Then, with the lapse of time, oxidation consumption of the carbon fibers located in the vicinity of the cutout portion progresses, the blow-through hole that was initially small becomes large, and the flame rises high from there.

In addition, when the reinforcing fiber material is a high-density woven fabric of the above-mentioned thin carbon fiber yarns, the woven fabric has a large number of perforations, that is, the distance between adjacent perforations is large. Since it is narrow, the flames blown out from each of the perforations gather together in a short time to form a large flame, which easily causes a situation of rising up. In addition, a skin material formed by stacking a plurality of fabrics so that their fiber orientations are in the same direction, or a plurality of fabrics having a fiber orientation of 0 ° / 90 ° and +
Even in the case of a skin material having a pseudo-isotropic mechanical property, which is laminated so as to have an angle of 45 ° / −45 °, originally, since each fabric has a large number of perforations, When overlapped, the frequency and area of overlapping of the punched portions also increase, and similar to the case described above, small flames blown out from the punched portions are likely to aggregate in a short time to form a large flame.

Further, when the carbon fiber woven fabric composited with the matrix resin is a high density woven thin carbon fiber yarn, it is obtained because the surface of the woven fabric becomes uneven due to the bending of the woven yarn. The skin material also has a problem that its surface becomes uneven, and the woven yarn itself is expensive, so that the sandwich structure material itself is expensive.

[0014]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems in the conventional sandwich structure material, is light in weight as a whole, is excellent in penetration resistance and burn-through property, has a smooth surface, and is inexpensive. The object is to provide a sandwich structure material that can be manufactured.

[0015]

In order to achieve the above object, in the present invention, a sandwich structure having a structure in which a fiber-reinforced resin plate composed of a reinforcing fiber material and a matrix resin is bonded to both surfaces of a core material. In the above, the reinforcing fiber material has a tensile elastic modulus of 20 × 10 ³ kgf / cm ² or more, and
Provided is a sandwich structure material comprising a carbon fiber yarn having a breaking strain energy of 4.0 mm · kgf / mm ³ or more.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of the sandwich structure material of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a partially cutaway perspective view showing a sandwich structure material A. In the figure, skin materials are adhered to both surfaces of a core material 1 which is a honeycomb structure, and each skin material is a fiber reinforced resin in which a plurality of (two in FIG. 1) reinforcing fiber materials 5a and 5b are laminated. It is a plate.

The core material 1 preferably has a density of 0.017 to 0.17 g / cm ³ in order to reduce the weight of the sandwich structure as a whole and to secure the mechanical strength. If the density is less than 0.017 g / cm ³ , the mechanical strength of the sandwich structure will be low, and the resulting sandwich structure will be prone to buckling, and will exert its full function as a core material of the structure material. I can't do it
This is because if the g / cm ³ is larger than that, the whole weight becomes heavy, which is against the intention of weight reduction.

As the core material 1, in addition to the illustrated honeycomb structure, a plastic foam may be used. When using the sandwich structure material as an aircraft interior material,
When the core material 1 is an aluminum honeycomb structure, the core material 1 is nonflammable, which is preferable. Further, a honeycomb structure obtained by impregnating a honeycomb of aramid fiber paper with, for example, a phenol resin, or a phenol foam obtained by foaming a phenol resin, for example, is suitable as the core material 1 because it is self-extinguishing and flame-retardant. is there.

Next, the skin material 2 will be described. The skin material 2 is a fiber-reinforced resin plate in which the reinforcing fiber material is made of carbon fiber yarn and the reinforcing fiber material and the matrix resin are combined. Examples of the matrix resin forming the fiber-reinforced resin plate include thermosetting resins such as epoxy resin, phenol resin, unsaturated polyester resin, and vinyl ester resin, polyamide resin, polyester resin, polyethylene resin, polypropylene resin, Examples thereof include thermoplastic resins such as polyphenylene sulfide resin, polyimide resin, polyether ether resin, ABS resin and acetal resin.

Examples of these matrix resins include phosphoric acid esters, halogenated hydrocarbons, antimony oxide, zinc borate, phosphorus-containing polyols, bromine-containing polyols, phthalic anhydride tetrachloride, and phthalic anhydride tetrabromide. A known flame retardant may be blended to impart flame retardancy. In that case,
When the matrix resin burns, gas components harmful to the human body may be generated from these flame retardants. Therefore, the amount of the flame retardant compounded should be limited to an appropriate amount.

Of the above matrix resins, the phenol resin has excellent flame retardancy without the addition of a flame retardant, produces a small amount of gas during combustion, and has a high carbonization rate. If so, it remains as a carbide, which is preferable because it exerts a function of blocking a flame. In this fiber reinforced resin plate, the composite ratio of the matrix resin is preferably 35 to 65% by weight. If this proportion is less than 35% by weight, the proportion of reinforcing fiber material is 6
If it is more than 5% by weight, and if it is more than 65% by weight, the proportion of the reinforcing fiber material is less than 35% by weight. Because it will be enough.

Next, carbon fiber used as a reinforcing fiber material
As the thread, PAN-based carbon fiber thread or pitch-based carbon
Although it may be any fiber thread, it has the following characteristics.
A high tenacity carbon fiber yarn is used. That is, JIS
 Tensile elastic modulus measured according to R7601 (E: kg
f / mm ²) Is 20 × 10³kgf / mm²That's it, and break
Breaking strain energy (W: mm ・ kgf / mm³) Is 4.0 mm / kg
f / mm³The above carbon fiber yarn.

Here, the breaking strain energy is the following formula: W = using the tensile strength (σ: kgf / mm ² ) measured according to JIS R7601 and the above E value. A value calculated based on σ ² / 2E. When a skin material is manufactured by using carbon fiber yarn having E of less than 20 × 10 ³ kgf / mm ^2, in order to impart appropriate penetration resistance and mechanical strength to the skin material, a relatively large amount of carbon fiber yarn is used. Therefore, the weight of the skin material becomes heavy, which is contrary to the purpose of weight reduction.

The breaking strain energy is 4.0 mm · kg.
In the case of a skin material manufactured using a carbon fiber yarn lower than f / mm ³ , when an external shock is applied to the skin material,
As the core material near the impact point is crushed, the carbon fiber thread itself compounded in the skin material is also easily cut,
Therefore, even when a low impact energy is applied, the skin material is likely to have holes.

As the carbon fiber yarn, a multifilament having a single yarn diameter of 4 to 10 μm is used.
One example of the reinforcing fiber material of the present invention is shown in a perspective view in FIG. The reinforcing fiber material B is a woven fabric obtained by weaving the weft thread 3a and the warp thread 3b using carbon fiber flat thread.

In this woven fabric, a perforated portion 4 is formed at the intersection of the weft thread 3a and the warp thread 3b. In the present invention,
The number of the perforated portions 4 is 400 to 60 per 1 m ^{2 of} the woven fabric.
It is preferable to use a woven fabric having 000 pieces and having the above-mentioned Cf value of 95% or more. Unit area (1m ² )
A woven fabric having a small number of perforated portions 4 has a large interval between adjacent perforated portions, so that when the skin material comes into contact with flames, the flames blown from the individual perforated portions gather to form a large flame. The time required for the growth to become longer and the burn-through property is improved.

However, if the number of the perforated portions 4 is too small, the woven fabric has a small degree of freedom with respect to shear deformation, and at the time of manufacturing the skin material, a prepreg obtained by impregnating the woven fabric with a resin is, for example, along a curved surface. When molding
Wrinkles will occur on the surface of the molded body. For this reason, it is preferable that the number of the perforated portions 4 in the woven fabric is 400 pieces / m ² or more.

If the number of the cut-out portions 4 is too large, the distance between the adjacent cut-out portions becomes small, so that the flames blown through the cut-out portions gather in a short time and grow into a large flame. Easily, and the burn-through property of the skin material deteriorates. Therefore, it is preferable that the number of the blank portions 4 is 60,000 / m ² or less. Further, in the woven fabric to be used, the woven fabric having a small Cf value has a large perforated portion area, so that the resin filling the perforated portion is burned and blows out from the perforated portion to grow into a large flame. The time will be shorter. Therefore, the woven fabric used in the present invention preferably has a Cf value of 95% or more.

As the woven fabric obtained by weaving the carbon fiber flat yarns shown in FIG. 2, specifically, there is no twist and the fineness is 3,000.
Flat yarn of 20,000 denier, yarn width 4-16 mm, yarn width / thread thickness ratio of 30 or more is woven at a pitch of 1.0 to 1.3 times the yarn width and a basis weight of 100 to 300 g. / M ² ,
A woven fabric having a thickness of 0.1 to 0.4 mm can be mentioned. In the case of this fabric, the carbon fiber yarn used for weaving has no twist,
Since the yarn width is large and the yarn width / thread thickness ratio is 30 or more,
The number of perforations 4 per unit area (1 m ² ) is 400 to
It can be 60,000 / m ^2, and has good burn-through properties, penetration resistance, and moldability.

Further, since the weaving is carried out at a pitch of 1.0 to 1.3 times the yarn width, the Cf value thereof is within the range of 95 to 99.5%, and the burn-through property is excellent. Furthermore, since this woven fabric is woven with flat yarn having a thickness of 0.1 to 0.4 mm, unevenness due to the bending of the woven yarn does not occur much on the surface of the woven fabric. Further, the basis weight is as small as 100 to 300 g / m ² .
Therefore, the skin material manufactured using this woven fabric has a smooth surface and is lightweight. Furthermore, since the carbon fiber thread used is thick, it can be manufactured at low cost, and the final sandwich structure material is also inexpensive.

The woven fabric shown in FIG. 2 can be woven as follows, for example. That is, the weft yarn is wound around the weft yarn bobbin around which the flat yarn is wound, and the weft yarn is horizontally positioned by the guide roller at the weft yarn feeding device position, and the space between the weft yarn bobbin and the guide roller is set. Then, while holding the weft thread of a length necessary for one-time supply of the weft thread to the warp thread, the weft thread is fed under tension. On the other hand, the warp yarns are wound and unwound from each of a plurality of weights of warp bobbins on which the warp yarns made of flat yarns are wound. Is woven by aligning the warp yarns to a desired density while avoiding contact with each other, converting the flat surface of each warp yarn into a horizontal direction and guiding the warp yarns to the heddle.

In the case of the woven fabric thus woven,
The warp yarn and the weft yarn are not twisted, the flat state of the warp yarn and the weft yarn is maintained, and the yarn shapes such as the yarn width and the yarn thickness hardly change. The sandwich structure material shown in FIG. 1 can be manufactured, for example, as follows.

First, a woven fabric of carbon fiber flat yarns as shown in FIG. 2 is immersed in a resin solution prepared by diluting a matrix resin with a solvent such as methanol to impregnate the woven fabric with the resin. Then, the woven fabric is taken out, the solvent is removed by drying, and a woven fabric prepreg to which a predetermined amount of resin is attached is prepared. A desired number of the obtained fabric prepregs are laminated, a core material processed into a desired shape is raised thereon, and further, after placing the desired number of the fabric prepregs on the core material,
The whole is set in an autoclave, and by heat-pressing at a predetermined temperature and a predetermined pressure, the matrix resin is cured to form a skin material, and the skin material and the core material are bonded together.

In the above-described embodiment, the reinforcing fiber material in the fiber-reinforced resin plate which is the skin material is a woven fabric of carbon fiber flat yarn, but the reinforcing fiber material of the present invention is not limited to this, and for example, It may be a unidirectional material or a woven fabric in which the carbon fiber yarns having the above-mentioned tensile elastic modulus and breaking strain energy are aligned in parallel in one direction. The skin material is
In the case of a fiber-reinforced resin plate obtained by laminating a plurality of reinforcing fiber materials, the reinforcing fibers in the surface material may be arranged so that they are aligned in the same direction, and the reinforcing fiber in each surface material, Mutually 0 ° / 90 ° and + 45 ° /-
It may be arranged at 45 ° and laminated so that the entire skin material exhibits pseudo isotropicity.

In that case, the reinforcing fibers of the reinforcing fiber materials 5b, 5b in the skin material 2 in FIG. 1 are oriented in the 0 ° / 90 ° direction with respect to the arrow p direction in the figure, and the reinforcing fiber material 5
It is preferable that a and 5a are oriented in + 45 ° / −45 ° direction with respect to the arrow p direction and are arranged in mirror symmetry with respect to the core material 1. Further, the carbon fiber flat yarn woven fabric shown in FIG. 2 and an ordinary carbon fiber woven fabric may be laminated to form a skin material. In that case, if the former skin material is placed in the outermost layer, the entire surface of the skin material becomes a smooth surface, and if necessary, it may be painted or another film may be attached to improve the design. Can be increased.

[0036]

As is apparent from the above description, the sandwich structure material of the present invention is lightweight, has excellent penetration resistance and burn-through properties, and is useful as an aircraft floor material or interior material. Is. This uses a carbon fiber yarn having a tensile elastic modulus of 20 × 10 ³ kgf / cm ² or more and a breaking strain energy of 4.0 mm · kgf / mm ³ or more as the reinforcing fiber material constituting the skin material. It is the effect that there is. In particular, when a woven fabric is used as the reinforcing fiber material, the number of perforations in the woven fabric is 400 to 60,000.
And pieces / m ^2, and the cover factor of (Cf) 95
This is the effect brought about by making it more than%.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention.

FIG. 2 is a perspective view of a carbon fiber flat yarn woven fabric showing an example of the reinforcing fiber material in the skin material of the sandwich structure material of the present invention.

[Explanation of symbols]

 1 Honeycomb structure (core material) 2 Skin material 3a Weft yarn made of carbon fiber flat yarn 3b Warp yarn made of carbon fiber flat yarn 4 Cutout portions 5a, 5b Reinforcing fiber material

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location B32B 5/26 7421-4F 17/04 Z 27/04 8413-4F 27/42 101 7421-4F

Claims (4)

[Claims] 1. A sandwich structure material comprising a core material and a fiber-reinforced resin plate made of a reinforcing fiber material and a matrix resin adhered to both surfaces of the core material, wherein the reinforcing fiber material has a tensile elastic modulus of 20 × 10 ³ kgf / A sandwich structural material comprising a carbon fiber yarn having a cm ² or more and a breaking strain energy of 4.0 mm · kgf / mm ³ or more. 2. The reinforcing fiber material includes a carbon fiber woven fabric,
The sandwich structure material according to claim 1, wherein the carbon fiber woven fabric has a number of perforations of 400 to 60,000 per m ² , and a cover factor of 95% or more. 3. The non-combustible or flame-retardant core material,
The sandwich structure material according to claim 1, which is a plastic foam or a honeycomb structure. 4. The sandwich structure material according to claim 1, wherein the matrix resin is a phenol resin.