JPH05105773A - Plate-like fiber-reinforced composite molded product - Google Patents

Abstract

PURPOSE:To provide the subject molded product achieved in both the improvement of the torsional physical property and in the light weight of the product and permitting the freedom of designs by arranging reinforcing fibers containing specific highly strong and highly elastic carbon fibers at a constant angle to the axis of a torsional deformation. CONSTITUTION:Reinforcing fibers containing carbon fibers having a tensile strength of 330kg/mm<2> and a tensile elastic modulus of 35X10<3>kg/mm<2> are arranged at an angle of 30-60 degree to the axis of torsional deformation to provide a plate-like fiber-reinforced composite molded product suitable for ski board structure members requiring light weights and high torsional physical properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate-shaped fiber reinforced composite material molded product, such as a ski structural member, which requires light weight and high torsional physical properties.

[0002]

2. Description of the Related Art As one type of fiber-reinforced composite material, a sandwich plate composed of a fiber-reinforced surface layer and a core material is widely used in the fields of aerospace and sports, as well as a single plate and a hybrid plate.

For example, among sandwich plates, a sandwich plate using a particularly lightweight core material is expected as a material having high specific strength and specific rigidity in bending deformation, but its twisting physical properties are not practically sufficient. , Has been a problem.

That is, since a lightweight core material generally has a low shear modulus, a sandwich plate using such a core material is
It is unavoidable that not only twisting but also deformation such as bending will be greatly affected by the core material, resulting in poor physical properties.

In this case, the thickness of the core material is generally increased in order to improve various physical properties to some extent.
However, when the thickness of the core material is increased, it is inevitable that the design freedom, which is a characteristic of the fiber-reinforced composite material, is restricted and the weight is increased.

In addition, in the case of further improving various physical properties, the physical properties of the fiber-reinforced composite material used in the conventional surface layer are limited. The physical properties of the sandwich plate are limited by the physical properties of the surface layer.

Therefore, in order to improve the physical properties of the sandwich plate to a practical level, the physical properties of the surface layer must be improved,
There is a problem that the thickness of the surface layer is increased, and as a result, the weight of the sandwich plate is significantly increased.

From the above, it has been a difficult problem in the sandwich plate using the lightweight core material to improve both the torsional physical properties and the degree of freedom in design including weight saving.

[0009] For example, in the case of a ski, high torsional physical properties for the purpose of improving stability and vibration damping at the time of skiing, weight reduction for the purpose of improving operability at the time of skiing, and productivity. There has been a demand for a large degree of freedom in design and an easy manufacturing method for the purpose of improvement. Traditionally,
Such skis have been designed or manufactured for the purpose of improving the torsional strength or torsional rigidity, reducing the weight, or improving the productivity [eg, JP-A-52-234].
34, JP-A-55-70275, JP-A-56-117.
6, JP-A-56-11077, JP-A-56-1107
8, JP-A-57-140149, JP-A-59-2144
70, JP-A-59-57680, JP-A-60-7258.
1, JP-A-62-16777, JP-A-2-13615
0].

However, in such a proposal, it is the actual situation that some or all of the above requests cannot be satisfied even if some of them are satisfied.

As an example, Japanese Patent Laid-Open No. 2-136150 discloses
A ski having improved torsional elasticity is disclosed. Here, a surface layer is provided in which PAN-based carbon fibers are via-crossed, that is, a layer of a unidirectionally aligned resin matrix composite material is arranged in a ± 45 ° direction with respect to the longitudinal direction of the intended ski, and laminated. Alternatively, a torque box structure in which a fiber-reinforced plastic material is wound around a core material, or a sandwich plate structure has been proposed.

However, in practice, in order to obtain the required torsional rigidity only by structurally devising a low elastic reinforcing fiber such as PNA type carbon fiber, a complicated and multi-layered laminated structure or torque box structure is used. In addition, there is a problem that the thickness of the entire molded product becomes large and the degree of freedom in design is significantly limited. Especially for skis,
In addition to torsional rigidity, other factors such as appropriate bending rigidity, weight, and convenient thickness are also important, and it is necessary to secure torsional rigidity as well as design flexibility.

[0013]

DISCLOSURE OF THE INVENTION As a result of intensive studies to solve the above problems, the present inventors have found that when a specific high-strength and high-elasticity carbon fiber is used as a part of the reinforcing fiber, various physical properties are improved. It is possible to obtain an excellent fiber-reinforced composite material, and a fiber-reinforced composite material molded product using this has a high degree of freedom in design, exhibits high torsional rigidity with a simple structure, and simplifies the manufacturing process. The inventors have found the present invention and have reached the present invention.

[0014]

That is, according to the present invention, at least 30 ° or more with respect to the axis of torsional deformation of a molded article.
Characterized in that it has reinforcing fibers oriented at an angle of ≤ °, and at least a part of the reinforcing fibers is a carbon fiber having a tensile strength of 330 kg / mm ² or more and a tensile elastic modulus of 35 × 10 ³ kg / mm ² or more. And a plate-shaped fiber-reinforced composite material molded article.

The reinforcing fibers used in the plate-shaped fiber-reinforced composite material molded product of the present invention have a tensile strength of usually 220 to 55.
0 kg / mm ² , preferably 250 to 480 kg / mm
² and the tensile modulus is usually 7.7 × 10 ³ to 80
× 10 ³ kg / mm ² , preferably 40 to 75 × 10 ^3.
fibers having kg / mm ² , eg carbon fibers,
Examples include aramid fiber, glass fiber and silica fiber.

And, at least a part of the reinforcing fiber, usually 50 to 100 vol%, preferably 60 to 100 vol.
%, The tensile strength is 330 kg / mm ² or more and 550 kg /
mm ² or less, preferably 360 kg / mm ² or more and 480
kg / mm ² or less and tensile elastic modulus of 35 × 10
³ kg / mm ² or more and 85 × 10 ³ kg / mm ² or less, preferably 40 × 10 ³ kg / mm ² or more and 75 × 10 ³ k
Carbon fibers of g / mm ² or less are used. The type is not particularly limited as long as it is a carbon fiber satisfying the above tensile strength and the above tensile elastic modulus, and various carbon fibers such as pitch-based carbon fiber, polyacrylonitrile-based or rayon-based can be used, but particularly pitch-based carbon fiber can be used. Most preferred are carbon fibers, among which pitch-based carbon fibers produced from optically anisotropic pitch.

As a method for producing the pitch-based carbon fiber, for example, the softening point is 100 to 400 ° C., preferably 150.
An optically isotropic pitch or an anisotropic pitch among coal-based or petroleum-based pitches having a temperature of up to 350 ° C.,
Particularly preferably, the content of the optically anisotropic phase is 60 to 100 v.
Using an optically anisotropic pitch of ol%, the above pitch is first melt-spun by a known method to give pitch fibers, and then in an oxidizing gas atmosphere, usually 50 to 400 ° C., preferably 10
A method is preferred in which the infusibilizing treatment is performed at 0 to 350 ° C., and then the carbonizing treatment is usually performed at 800 to 3,000 ° C. in an inert gas atmosphere to obtain carbon fibers. Examples of the oxidizing gas include air, oxygen, nitric oxide, sulfur oxide, halogen, or a mixture thereof. Examples of the inert gas include Ar, He, Xe, Rn, N ₂ gas and the like.

The reinforcing fiber has a tensile strength of 330 kg / mm.
Not containing ^two or more carbon fibers at all is not preferable because the torsional rigidity is significantly deteriorated.

The reinforcing fiber is usually 100 to 25,000.
The number of fibers is preferably 200 to 12,000, and is usually used as a unidirectional laminate, a two-dimensional woven fabric, a three-dimensional woven fabric, a braided structure, or a state in which the woven fabric or the structure is laminated, It is desirable to be in an axially oriented state. For example, in order to impart symmetry to the target molded product, it is desirable that the molded product be in a biaxial orientation state. Further, it is very preferable to use a woven fiber or a braided structure as the reinforcing fiber, because the workability can be greatly improved and a sufficient performance can be obtained.

In the plate-shaped fiber-reinforced composite material molded product of the present invention, at least a part of the reinforcing fiber has a fiber direction of 30 ° or more and 60 ° or less, preferably 35 ° or more with respect to the axis of torsional deformation of the molded product. 55 ° or less, more preferably 40 ° or more 4
Some have a direction of 5 ° or less. The ratio can be appropriately selected depending on the purpose, but usually 60 to 100 of the reinforcing fiber
Vol%, especially about 70 to 100 vol% is desirable.
When the ratio of the reinforcing fibers having the above-mentioned angle is small, the reinforcing effect of the reinforcing fibers is insufficient, and the twisting physical properties are deteriorated.

As the resin with which the reinforcing fibers are impregnated, a thermosetting resin is usually used, and examples thereof include unsaturated polyester resin, vinyl ester resin, epoxy resin, phenol resin, furan resin, polyimide resin and the like. Resins, mixtures thereof, and the like.
Among these, when a resin having a curing temperature of usually 100 ° C. or lower, preferably 90 ° C. or lower, and most preferably 80 ° C. or lower is used, the material of the core material in the case of simultaneously performing adhesion and curing with the core material It is very desirable because the selection range is widened and a core material having a relatively low Tg can be used. Examples of such a resin include a resin obtained by adding the above thermosetting resin with a curing agent such as an imidazole curing agent and an isocyanate curing agent.

The method of impregnating the above-mentioned resin into the reinforcing fibers is not particularly limited, and examples thereof include a method of introducing the reinforcing fibers into a resin tank, a hand lay-up method in which the reinforcing fibers are coated with a resin by a brush, and a impregnation method. It can be performed by a resin injection method or other known methods.

The ratio of the reinforcing fiber to the resin is appropriately selected depending on the intended use of the molded product, etc., but the fiber content in the impregnated product is usually 30 to 75 vol%, preferably about 40 to 65 vol%.

As a method of forming a molded product by impregnating the above-mentioned reinforcing fibers with a resin, a known method is appropriately used. When adhering to a core material or the like, a method suitable for the material used for the core material can be selected.

As a method of forming a molded product by impregnating reinforcing fibers with a resin, for example, the reinforcing fibers are first impregnated with the resin, and then the resin is cooled and semi-cured to produce an intermediate,
Further, a method using a so-called prepreg, in which the intermediate is molded and laminated, and the intermediate is cured and molded and bonded at the same time,
Place the reinforcing fiber on the mold, impregnate the resin with a brush and a roller, place the reinforcing fiber and repeat the step of impregnating the resin with a hand lay-up method, impregnating the reinforcing fiber with the resin by spraying and roller. Spray-up method, prepreg sheet is laminated in a mold so that it has a predetermined orientation angle, and is cured by molding in an autoclave with a vacuum bag or a pressure bag. The reinforcing fiber is placed in the mold and the mold is closed. Examples of the method include a method of simultaneously injecting and molding by injecting a resin into a mold at a low pressure later, a pull-through method, a filament winding method, and the like.

The thus-obtained plate-shaped fiber-reinforced composite material molded article of the present invention can be used not only alone, but also by being bonded to another material such as a core material. The core material is not particularly limited, and examples of the resin material include vinyl chloride,
Foams of various resins such as polyurethane, ABS, epoxy resin, phenolic resin, styrene, and the like, in which the short fibers of the fiber material and microballoons are included as a reinforcing material in the foams, and further, honeycombs such as aluminum honeycombs and aramid honeycombs It is possible to use an extremely lightweight core material such as a structure, balsa, and walnut.

When used by adhering to another material such as the core material as described above, first, another material and the above-mentioned intermediate or intermediate laminate are laminated, and the adhesion is performed simultaneously with curing of the intermediate. Is desirable.

When a lightweight core material is used, it is desirable to use an adhesive agent when the core material and the plate-shaped fiber-reinforced composite material molding of the present invention are bonded. Examples of the adhesive include epoxy resin, phenol resin, urethane resin, silicon resin, nitrile resin, thiol resin, etc., preferably epoxy resin, phenol resin, etc. It is desirable that it has at least a necessary and sufficient shear strength, usually a shear strength of 1 kg / mm ² or more, in addition to a thin film adhesive, for example, an adhesive having a thickness of about 0.2 mm. Using is an effective means for improving productivity.

[0029]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

Example 1 Tensile strength of 36 as reinforcing fiber
0 kg / mm ² , tensile elastic modulus 41 × 10 ³ kg / mm
A two-dimensional fabric of 2,000 bundles of ² carbon fiber, bisphenol A type epoxy resin as a thermosetting resin, imidazole curing agent, the predetermined amount added resin blend filler was prepared and further, reinforcing fibers Impregnated with the above resin mixture,
I got a prepreg.

Next, on the upper and lower surfaces of the core material of the rigid vinyl chloride foam, the direction of the reinforcing fibers was 45 ° with respect to the axis of torsional deformation.
The above prepregs were laminated one by one on the upper and lower sides so as to form an angle of.

The temperature is 90 ° C. and the pressure is 0.5 kg / cm.
^3. By subjecting to autoclave molding under the condition of 1 hour, the surface layer was cured and the surface layer and the core material were adhered at the same time to obtain a target plate-shaped fiber-reinforced composite material molded product. The size of the obtained molded product was 40 cm in the axial direction of torsional deformation, 7 cm in the direction perpendicular to the axis, and 0.6 cm in the thickness direction.

Both ends of the obtained molded product were clamped by jigs, one end was fixed, and a torsional torque was applied to the other end, and the torsional rigidity was measured from the relationship between the torque and the torsion angle.

Example 2 In Example 1, the reinforcing fiber had a tensile strength of 400 kg / mm ² and a tensile elastic modulus of 50.
A molded product having the same dimensions as in Example 1 was obtained using 0 × 10 ³ kg / mm ² of carbon fiber. The torsional physical properties of the obtained molded product were measured in the same manner as in Example 1 and shown in Table 1.

Example 3 In Example 1, the reinforcing fiber had a tensile strength of 400 kg / mm ² and a tensile elastic modulus of 41.
A molded product having the same dimensions as in Example 1 was obtained using 0 × 10 ³ kg / mm ² of carbon fiber. The torsional physical properties of the obtained molded product were measured in the same manner as in Example 1 and shown in Table 1.

Example 4 In Example 1, the reinforcing fiber has a tensile strength of 400 kg / mm ² and a tensile elastic modulus of 41 ×.
Carbon fiber of 10 ³ kg / mm ² and tensile strength of 282k
g / mm ² , tensile modulus of 13.4 × 10 ³ kg / mm
A molded article having the same size as in Example 1 was obtained by using a woven fabric structure in which ² aramid fibers were mixed and woven at a fiber volume ratio of 3: 1. The torsional physical properties of the obtained molded product were measured in the same manner as in Example 1 and shown in Table 1.

(Comparative Example 1) In Example 1, the reinforcing fiber has a tensile strength of 250 kg / mm ² , and a tensile elastic modulus of 7.7.
A molded product having the same dimensions as in Example 1 was obtained by using × 10 ³ kg / mm ² of glass fiber. The torsional physical properties of the obtained molded product were measured in the same manner as in Example 1 and shown in Table 1.

(Comparative Example 2) In Example 1, the reinforcing fiber had a tensile strength of 360 kg / mm ² , and a tensile elastic modulus of 23.
Using a unidirectional prepreg of carbon fiber of 5 × 10 ³ kg / mm ² , a molded product having the same dimensions as in Example 1 was obtained. The torsional physical properties of the obtained molded product were measured in the same manner as in Example 1 and shown in Table 1.

[0039]

[Table 1]

According to Table 1, the reinforcing fiber has a tensile strength of 360.
kg / mm ² , tensile elastic modulus 70.0 × 10 ³ kg / m
The torsional rigidity of Example 1 using m ² of carbon fiber was about 4.4 times that of Comparative Example 1 using only glass fiber as the reinforcing fiber,
This shows about 2.2 times that of Comparative Example 2 in which only low elasticity carbon fibers were used as the reinforcing fibers. Further, the tensile strength is 400 kg / mm ² , and the tensile elastic modulus is 41.0 × 10 ^{3 in} 75% of the reinforcing fibers.
The torsional rigidity of Example 4 containing kg / mm ² of carbon fiber was about 2.9 times that of Comparative Example 1 using only glass fiber as the reinforcing fiber, and Comparative Example using only low elastic carbon fiber as the reinforcing fiber. 2 is about 1.4 times.

[0041]

INDUSTRIAL APPLICABILITY As described in the above examples, according to the present invention, by using carbon fiber having high elasticity and high strength as a part of the reinforcing fiber, the twisting property of the plate-shaped fiber reinforced composite material molded article is improved. It realizes the expression, and because of such excellent strengthening effect, the effect is easily expressed even in a small amount, so it is easy to reduce the weight, a simple structure can be adopted, and the manufacturing process can be simplified. Thus, it is also effective in improving the productivity of the plate-shaped fiber-reinforced composite material molded product. Further, according to the present invention, since a high twist physical property can be realized without increasing the thickness of the plate-shaped fiber reinforced composite material molding, the degree of freedom in designing the molded product is large.

Claims (1)

[Claims] 1. A reinforcing fiber oriented at an angle of 30 ° or more and 60 ° or less with respect to an axis of torsional deformation of a molded article, and at least a part of the reinforcing fiber has a tensile strength 33.
0 kg / mm ² or more and tensile elastic modulus 35 × 10 ³ kg /
A plate-shaped fiber-reinforced composite material molded product, which is a carbon fiber having a size of mm ² or more.