JPH04146252A - Reinforcing fiber sheet and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject sheet, excellent in impregnating properties with resins and molding processability and suitable as reinforcing compositions good in mechanical performance by arranging the fiber longitudinal direction, orienting the fiber and specifying the ratio of tensile strength in the orienting direction to the direction intersecting at right angles thereto, bulkiness, etc. CONSTITUTION:The fiber length direction of fiber (bundle) such as carbon fiber, glass fiber or aramid fiber is arranged. The fiber bundle is then oriented in the sheetlike form and a liquid flow, e.g. water is subsequently jetted from small holes having preferably <=0.5mm diameter to mutually entangle fiber and afford the tensile strength in the orienting direction of the fiber in the sheet of 50 to 10<3> times based on that in the direction intersecting at right angles thereto. Thereby, the objective reinforcing fiber sheet having 0.2-0.7 bulkiness is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a reinforcing fiber sheet used as a molding material for fiber-reinforced plastics.

More specifically, the present invention relates to a reinforcing fiber sheet that can provide a fiber-reinforced resin material that has good resin impregnation properties, excellent moldability, and excellent mechanical performance.

(Prior art) Fiber-reinforced materials made by bonding reinforcing fibers with matrix resin have excellent properties such as high strength, high rigidity, low specific gravity, and high fatigue resistance. It is expected to have many uses and is attracting attention as an industrially important material.

The reinforcing fibers used in such materials are, for example, in the form of sheets such as woven fabrics, knitted fabrics, and non-woven fabrics, or in the form of yarns with the fibers aligned in one direction, depending on the type of fiber or the characteristics of its form. It is intended for various uses.

Among these forms of reinforcing fibers, fiber-reinforced materials used in the form of yarns with fibers aligned in one direction are preferably used as high-performance materials because of their excellent mechanical performance. However, in order to arrange the fibers in the same direction, it is necessary to arrange the bundles of fibers in the same order in the same direction and adjacent to each other, which improves operability and work efficiency. In this respect, it is extremely inferior.

On the other hand, sheet-like materials in which mII is aligned and connected in one direction, or methods for manufacturing these, are already known. The fibers of the upper and lower layers are entwined and pulled out repeatedly using a burr on the needle to form a sheet, or the so-called needle punch method is used to entangle the fibers with each other using a high-pressure gas flow to form a non-woven fabric. (Japanese Unexamined Patent Publication No. 59-66554), or a method in which a high-speed incompressible fluid, water stream, etc. is applied to fiber bundles arranged in one direction to intertwine the fibers to form a nonwoven sheet. Also, Japanese Patent Publication No. 4B-13749 and Japanese Patent Application Laid-Open No. 52-1
This method is disclosed in Japanese Patent Publication No. 40667 and Japanese Patent Publication No. 59-5406.

In particular, Japanese Patent Publication No. 59-5406 describes an example of using carbon fiber as a reinforcing fiber, which has excellent handling, transportation, and moldability, and has excellent strength in the direction perpendicular to the fiber alignment direction of the resulting fiber-reinforced plastic product. It is disclosed that it can be increased.

(Problem II to be Solved by the Invention) However, it is clear that the fiber sheets obtained by the above-mentioned conventional techniques are still not satisfactory as reinforcing fiber sheets for obtaining high-performance fiber-reinforced resin materials. It became.

That is, for example, a sheet obtained by the needle punching method has strong vertical entanglement of fiber layers and is extremely bulky due to repeated mechanical penetration of needles through the fiber bundle up and down in order to form an integrated sheet. Become. As a result,
The amount and ratio of resin to be impregnated is high (and the reinforcing fibers cannot fully demonstrate their performance. In addition, the fiber itself is severely damaged by the mechanical penetration operation of the needle, and the hole of the needle hole is This is also a serious hindrance to achieving high performance.This is particularly noticeable in glass fibers or carbon fibers that are used as fiber-reinforced resin materials because these fibers are rigid and brittle.

In the sheet disclosed in Japanese Unexamined Patent Publication No. 59-66554, the directionality of the fiber sheet is significantly disturbed by the compressible gas flow, and it is almost impossible to apply the sheet to a fiber sheet whose direction is aligned. Furthermore, due to the gas flow, the mass is small and the velocity attenuation is large, and sufficient entanglement within the fiber layer cannot be obtained, resulting in poor handling and operability.

On the other hand, Special Publication No. 4B-13749, Special Publication No. 59-5
The sheet disclosed in Japanese Patent No. 406 is a sheet in which fibers are entangled and integrated by a high-pressure liquid flow. As described in, for example, Japanese Patent Publication No. 595,406, such sheets are treated with a high-pressure liquid stream of 50 to 500 kg/C4, and as a result, the fibers become stiff, especially in the case of rigid and brittle fibers such as glass fibers and carbon fibers. It is difficult to provide a high-performance fiber-reinforced material because the fibers are severely damaged by cutting, etc., and the degree of entanglement is strong and bulky. Furthermore, due to the high-pressure liquid flow treatment, there are many entanglements in the fiber length direction, and the direction of fibers aligned in one direction is also greatly disturbed.

This is supported by the fact that the strength in the direction perpendicular to the fiber length direction increases, but it causes a decrease in performance in the fiber length direction, and reinforcement is required to obtain high-performance fiber-reinforced resin materials. It is not preferable as a fiber sheet for use.

The present invention was carried out for the purpose of obtaining a reinforcing fiber sheet for obtaining a high-performance fiber-reinforced resin material,
This is an attempt to solve the above-mentioned problem in which the conventional technology focuses on integration to form a sheet, which hinders high performance.

As a result of extensive research in line with the above objectives, the present inventor has found that
As a reinforcing fiber sheet, the strength ratio between the direction in which the fibers are arranged and the direction perpendicular thereto is within a certain range;
and that in order to achieve high performance, the objective can only be achieved by increasing the ratio of reinforcing fibers in resin impregnation and achieving a specific bulk density that enables uniform impregnation and molding with a small amount of resin; Furthermore, it was surprisingly discovered that the resin impregnation rate could be increased by using such a reinforcing fiber sheet, and the present invention was completed based on this finding.

(Means for Solving the Problems) The first aspect of the present invention is that the fibers are made of one or more of carbon fibers, glass fibers, and aramid fibers, and the fibers are arranged with substantially the same fiber length direction. A sheet in which fibers are intertwined with each other in preset areas of the sheet, which has: (1) tensile strength (T) in the direction in which the fibers are arranged;

) and the tensile strength (T, .) in the direction perpendicular to this is 50≦T o /T 90≦103. and (1
1) A reinforcing fiber sheet whose bulk density, obtained by dividing the bulk density of the sheet by the density of the fibers constituting the sheet, is 0.2 to 0.7. In a method for producing a nonwoven fiber sheet by applying a flow, fibers or fiber bundles made of one or more of carbon fibers, glass fibers, and aramid fibers are arranged with substantially the same fiber length direction. A fibrous web with a diameter of 0.5 mm is applied onto a predetermined surface area in the fibrous web and along its length, while absorbing liquid from the back side of the fibrous web through a porous support.
2 kg/cj or more 50k ejected from the pores below
This is a method for producing a reinforcing fiber sheet, characterized in that the fibers are entangled with each other by applying at least one liquid stream having a pressure of less than g/II.

The present invention will be explained in detail below.

The fibers constituting the reinforcing fiber sheet of the present invention are one or more of carbon fibers, glass fibers, and aramid fibers. Carbon fibers include, for example, flame-resistant fibers obtained by oxidizing and firing polyacrylonitrile fibers, carbonaceous or graphite fibers, pinch-type carbonaceous fibers, or carbonaceous fibers derived from cellulose fibers. It refers to carbon fiber in a broad sense, and glass fiber, which is not particularly limited, also refers to fibers made of, for example, E-glass, S-glass, T-glass, etc.

Aramid fiber is a general term for fully aromatic polyamide fibers, and consists of a polymer in which divalent aromatic residues such as benzene rings and naphthalene rings are directly connected by amide bonds (-C-N-). Among these fibers, rose-oriented aramid fibers in which both amide bonds are connected at the rose position of the aromatic ring are particularly preferred because they have excellent properties such as high strength, high elastic modulus, and high heat resistance. Specifically, fibers made of polybara phenylene terephthalamide, 3.4° or 4°
, 4°-diaminodiphenyl ether group as a copolymer component, but the fibers are not limited thereto.

One type of such fiber may be used, or two or more types can be used in combination. The fiber diameter of these fibers is usually 6 μm.
A thickness of 50 μm or more may be used, but is not particularly limited. From the viewpoint of fiber entanglement for forming a sheet, it is advantageous for the fiber diameter to be relatively small, so it is particularly preferably 4 to 40 μm, more preferably 6 to 30 μm.

In the present invention, the above-mentioned fibers may be continuous long fibers or discontinuous so-called short fibers. Continuous long fibers are preferred because the resulting reinforcing sheet has high morphological stability and high mechanical performance can be obtained when used as a fiber-reinforced resin material. Even in the case of discontinuous short fibers, the effects of the present invention are not particularly impaired;
Although there is no particular restriction on the fiber length, short fibers with a length of 25 m or more are usually preferably used because long fiber lengths are advantageous for high-performance fiber-reinforced materials. . In addition, when short fibers are used, when used as a fiber-reinforced resin material, an additional feature is that the material has excellent moldability, particularly shapeability.

In the reinforcing fiber sheet of the present invention, it is important that the fibers are arranged with substantially the same fiber length direction. That is, in the fiber reinforced resin material, its mechanical performance exhibits its reinforcing effect most prominently in the fiber length direction. Therefore, the more the length directions of the fibers used are aligned, the more efficiently mechanical performance can be exhibited.

In the present invention, "arrayed with substantially the same fiber length direction" means that each fiber is arranged substantially parallel to the averaged fiber length direction of the entire sheet. Although it is not possible to accurately define the degree of fiber alignment for each fiber, the specific degree of alignment can be determined by the ratio of the tensile strength in the fiber length direction and the tensile strength in the direction perpendicular to this, which will be described later. It is specified by

In the reinforcing fiber sheet of the present invention, the fibers are intertwined with each other in preset areas to form a sheet. "Preset area" does not mean a specially selected area, but refers to an area where some of the fibers forming the sheet are intertwined with other fibers in order to maintain the form of the sheet. Such areas may be uniformly distributed throughout the sheet, or may be concentrated at particular locations, for example, in the middle or along the length of the sheet.

For ease of handling and handling as a reinforcing fiber sheet, it is preferable that the intertwined areas exist uniformly throughout the sheet. The ratio of the area of entanglement to the total sheet and the degree of entanglement are defined by two factors that specify the reinforcing fiber sheet of the present invention, detailed below.

In the reinforcing fiber sheet of the present invention, the ratio of the tensile strength (T0) in the direction in which the fibers are arranged to the tensile strength (T, .) in the direction perpendicular to this is 50≦T0/T. It is important that ≦103.

The tensile strength (T0) in the direction in which the fibers are arranged approaches the tensile strength of the reinforcing fibers as the degree of arrangement of the fibers increases, while the tensile strength (T,) in the direction perpendicular to this, If the fibers are not entangled with each other and the fibers are arranged in one direction, it is O. Therefore, tensile strength (T9°) is a factor that indicates the degree of entanglement and the degree of fiber arrangement.
Tensile strength (T.

) and tensile strength (T, .) is also a factor indicating the degree of entanglement and the degree of fiber alignment.

T,/T,. is 50 or less, the entanglement in the direction perpendicular to the fiber alignment direction is strong, resulting in a bulky sheet, or the degree of fiber alignment is low and the tensile strength (T) is insufficient. This means that it is not expensive, and in any case it is not possible to provide a high-performance fiber-reinforced resin material. On the other hand, Tll/bottom. If it is 103 or more, the fibers are insufficiently entangled, making it difficult to maintain the form of a sheet during handling, making it impossible to put it to practical use. That is, in order to obtain a reinforcing fiber sheet that maintains its shape, handleability, and operability as a sheet and obtains a high-performance fiber-reinforced resin material, the tensile strength ratio of the sheet should be T, /T. As mentioned above, 50≦T, /T,
. The first requirement is that ≦10'.

The second essential requirement for the reinforcing fiber sheet of the present invention is:
The bulk density of the sheet is 0.2 to 0.0. It is to be 7.

Even if the degree of fiber alignment is high and satisfies the first requirement above, if the bulk level is 0.2 or less, the amount of resin and reinforcement will be insufficient to obtain a fiber-reinforced resin material that is uniformly impregnated with resin. The ratio of resin to fiber cannot be lowered, and high-performance materials cannot be obtained.

On the other hand, if the bulkiness is 0.7 or more, the degree of entanglement is so low that the sheet form cannot be maintained, or the resin impregnation property is significantly reduced due to the fine densification of the fibers, which is not preferable. The bulk level involved in entanglement is 0.2 to 0.7
It is important that the ratio be within the range of 0.3 to 0.5.

By satisfying the above-mentioned first and second requirements, it is possible to improve the handleability and operability as a sheet and the performance of the resulting fiber-reinforced resin material. Furthermore, by satisfying both requirements, the reinforcing fiber sheet of the present invention has an additional effect of absorbing liquid due to the entangled portions and increasing the impregnation rate of the resin by channeling the resin flow along the arranged fibers. It has a combination of effects.

The method for manufacturing the reinforcing fiber sheet of the present invention is as detailed below.

In the manufacturing method of the present invention, fibers or fiber bundles made of one or more of the carbon fibers, glass fibers, and aramid fibers described above are arranged with their fiber length directions aligned.

The method of arranging the fibers or fiber bundles with their fiber length directions aligned is not particularly limited, and any known method may be used.For example, a plurality of multifilament yarns wound around a bobbin or paper tube may be , a method in which a bundle of multifilament yarns is wound on a cylindrical drum, for example, and wound in a cylindrical shape while shifting the winding position to avoid overlapping, and then pulled out in one place on the drum. For example, if the fiber is a discontinuous fiber, it may be stretched using a carding device. In short,
It is sufficient that the fibers or fiber bundles are arranged with their fiber length directions aligned.

The fibrous web thus obtained is then subjected to a stream of liquid ejected through pores having a diameter of less than 0.5 mm in order to entangle the fibers. In this case, it is necessary that the liquid stream be ejected from pores with a diameter of 0.5 square centimeters or less. The preferred pore diameter, the distance from the pore to the fiber web, and the number of pores vary depending on the fiber diameter (thickness) and the thickness of the fiber web, but when the pore diameter is 0.5 m or more, This is because a large amount of fibers are agitated by the liquid flow at the same time, which tends to disturb the arrangement of the fibers, and the thickness of the fiber web becomes uneven, making it difficult to obtain the desired sheet. In view of the above, it is particularly preferable that the diameter of the pores is 0.05 to 0.3 mm.

The number of pores, that is, the number of liquid streams that can be simultaneously applied is not particularly limited in the method of the present invention, and it is sufficient that there is at least one liquid stream. The number of liquid streams applied at the same time can be appropriately set in consideration of the length, width, etc. of the fibrous web to be treated.

The distance between the pores and the fiber web is determined by the pressure of the liquid flow, the thickness of the fibers, the thickness of the aiit web, etc., but as this distance increases, the spread of the liquid flow increases, the entanglement effect decreases, and the fiber This is not preferable because it increases the disturbance of the web, and it is usually set to about 1 to 20 III.

The pressure of the liquid stream is an important factor in the method of the present invention, and 2
50 or more kg/cd or more is required. Naturally, the details of the pressure of the liquid flow vary depending on the thickness of the liquid flow mentioned above, the distance between the pores and the fiber web, the thickness of the fiber web, etc., but at a low pressure of 2Icg/Cd or less, the fibers are Unable to connect effectively. On the other hand, 50
At pressures exceeding kg/C11l, carbon fibers and glass fibers that are subject to the method of the present invention, except aramid fibers, break.
This not only causes frequent breaks and fluff, which reduces the quality of the sheet obtained, but also results in a bulky sheet, which reduces the mechanical performance when used as a fiber-reinforced resin material. In the case of aramid fibers, although almost no breakage is observed, excessive waviness of the fibers causes frequent loop-like fluff, which is undesirable.

The liquid stream used for entanglement in the method of the present invention is usually water due to its versatility, economy, ease of handling, etc., but organic solvents such as alcohol and ether, or aqueous solutions thereof , low viscosity oils, etc. may be used.

In the method of the invention, the liquid stream described above is applied onto a predetermined surface area across the width and length of the fibrous web.

The predetermined surface area does not mean a specially selected area as mentioned above, but rather a predetermined surface area where some of the fibers forming the sheet are intertwined with other fibers in order to maintain the form of the sheet. Such areas may be uniformly distributed throughout the sheet, or may be concentrated at particular locations, for example along the width or length of the sheet.

For ease of handling and operability as a reinforcing fiber sort, it is preferable that the intertwined areas exist uniformly throughout the sheet.

Specifically, this is carried out by applying the above-mentioned liquid stream onto the fibrous web while shifting its position, for example, in the width and/or length direction of the fibrous web.

By repeating this operation at regular intervals or randomly changing positions on the fiber web, an integrated sheet can be obtained. The area of application of the liquid stream often provides a trajectory, for example zigzag, loop, etc., on the fibrous web. Alternatively, by intermittently applying a liquid stream while moving the fibrous web, entangled portions can be scattered on the fibrous web, and even with this method, a sheet can be obtained. Such an operation can be performed while moving the pores, or while moving the fibrous web, or both at the same time. A continuous sheet can be obtained by applying a liquid flow while reciprocating or moving in a circular motion in a direction perpendicular to the supply direction.

In the method of the present invention, when the above-mentioned liquid stream is applied to the surface of the fibrous web, it is important that the applied liquid is expelled from the back surface of the fibrous web via the porous support. The need for liquid absorption is due to the fact that the liquid stream originating from the pores and impinging on the fiber web loses its kinetic energy and accumulates, preventing new liquid streams from directly impinging on the fibers. This is because love cannot be continued. Furthermore, the fibrous web is immersed in the deposited liquid, which causes the arrangement of the fibers to be disturbed.

By absorbing the liquid in this manner, the fibers can be entangled efficiently without disturbing the arrangement of the fibers. The degree of liquid absorption varies somewhat depending on the diameter of the pores, the pressure of the liquid flow, the thickness of the fibrous web, etc., but it should be carried out based on the level at which the liquid is not deposited on the fibrous web. Specifically, liquid absorption is achieved by providing a box with slit openings in the area hit by the liquid flow through a porous support, and reducing the pressure inside the box, and the degree of liquid absorption is determined by You can adjust it by adjusting the degree of vacuum inside the box.

The function of the porous support is to support the fibrous web while preventing the fibrous web from moving and flowing out due to liquid absorption, and usually a wire mesh is used. The mesh opening, wire diameter, etc. of the wire mesh are appropriately set depending on the degree of liquid absorption and various factors of the fibrous web, such as the thickness of the fibers and the thickness of the fibrous web. It may be made of a material other than wire mesh, for example, a perforated plate with slit-like or circular holes may be used.

The reinforcing sheet in which the fibers are intertwined in this way is usually then dried, but in some cases, various processing agents may be applied to the reinforcing sheet while it is still wet after the liquid flow treatment or during the drying process. Granting, etc. may also be performed. Examples of such treatment agents include various surfactants, ultraviolet absorbers, pastes, adhesives, etc. for improving fiber surfaces. Furthermore, the bulkiness of the sheet or the surface flatness may be improved by pressurizing or heating and pressing the reinforcing fiber sheet before drying, during drying, or after drying.

EXAMPLES Hereinafter, the present invention will be explained in more detail using examples. However, the present invention is not limited to these Examples in any way.

In addition, in the examples, unless otherwise specified, % means weight %.
The tensile strength and bulk density were measured by the methods shown below.

tensile strength T, and T,. A test piece with a length of 120 mm and a width of 25 mm was cut out in each direction, and a tensile test was performed at a grasping length of 50 m and a tensile speed of 50 mm/min, and the average value of n = 10 was determined [kg/25
1111].

Bulk height: The bulk density of the sheet was determined by the following formula, and was divided by the fiber density determined by the density gradient tube method.

[Here, W: Measuring size of the sheet (g/bo) t: 1.15
Sheet thickness (m) when a load of g/■2 is applied Example 1 Polyacrylonitrile carbon fiber yarn (Hicarboron 12Kf manufactured by Shin-Asahi Kasei Carbon Fiber Co., Ltd.)
Pull out the yarn (12,000 single fibers) from the bobbin, squeeze it through the guide, make the yarn width about 4.1 mm, and put it into a 9 meter drum wine goo with a circumference of 1.5 meters and a width of 1 meter.
It was rolled out and wound at a speed of /min. At this time, the drum wine goo is rotated at 6 rpm, and the yarn guide is rotated at 24 rpm.
It was set to traverse from one end of the drum to the other at a speed of m/min. After winding the yarn 125 times in this way, an adhesive tape with a width of 30 m is pasted at one point in the middle of the drum to prevent the yarn from falling apart, and then the yarn is cut together with the adhesive tape using a canter. Removed from goo and medium 50c
A aligned carbon fiber yarn array sheet with a length of 1.5 m and a length of 1.5 m was obtained.

This sheet was placed on the net of the net process l shown in Figure 1 so that the length direction of the fibers matched the moving direction of the net, and the entangling treatment was performed by applying a water stream under the water pressure conditions shown in Table 1. . At this time, the net speed was 4 m/min, the diameter of the pores that spouted the water was 0.21φ, and the width of the net was 5 m/min.
It is installed over the entire length of the net width at the cabinet pitch, and the liquid method jetting device 2 is installed in the width direction of the net to control the reciprocating movement of the five cabinets for 15 orps.
It was given with a period of m. Note that the distance between the pores and the surface of the fiber sheet is 12 mm. In addition, a suction box 3 with a 20-hole slit opening is installed at the bottom of the net in accordance with the position of the liquid method jetting device 2. A liquid operation was performed.

The sheet thus obtained was dried in a hot air dryer at 180°C for 2 hours. The characteristic values of the obtained reinforcing fiber sheet are shown in Table 1, and the sheet of the present invention had less disordered fiber arrangement and was excellent in handling as a sheet.

Example 2 Experiment N011a, lc, 1f, 1g obtained in Example 1
A fiber-reinforced resin material was prepared by impregnating the reinforcing fiber sheet with resin at 5 points for 1 hour.

After drying each sort at 120°C for 2 hours, epoxy resin (Epicoat #828) with methyl ethyl ketone as solvent was used.
．． 100 copies, BF3MEA3PHRMEK150PHR
) and then dried at 120°C for 15 minutes. In this way, when an impregnated sheet with a thickness of about 0°1111 is formed, the maximum fiber volume content Vfma that does not contain voids is obtained.
I found x.

Furthermore, these impregnated sheets were laminated with the fibers arranged in the same direction, and a laminate was formed with dimensions of 150 mm x 150 m x 3 mm, and its bending properties were measured. The results are shown in Table 2, and it was found that the reinforcing fiber sheet of the present invention had good impregnation properties, a high fiber volume content, and excellent mechanical properties.

Comparative Example 1 The treatment was carried out in the same manner as in 1f of Example 1, except that the liquid suction operation using the suction box was not performed when applying the water stream. As a result, by applying a water stream, excess water is absorbed and soaked into the sheet, causing the sheet to swell.
The fibers became disordered, resulting in a sheet with holes in some places. T − / T I of the part without holes of this sheet. is 1
5 Bulk height is 0. It was 21. Using this, the same experiment as in Example 2 was conducted, and as a result, V fmax was 48vo
1%, bending strength and elastic modulus are each 94 kg/
m'' and 6200 kg/m'', and the mechanical properties when used as a fiber reinforced resin material were also extremely poor.

Example 3 Glass fiber yarn (manufactured by Nippon Electric Glass Co., Ltd., ER735 single fiber diameter 13 μm, number of fibers 2200)
A reinforcing fiber sheet was created using this method. At this time, the liquid flow used was a water flow, and the water pressure was 30 kg/c-j. T, /T, of the obtained reinforcing fiber sheet. is 2
78, the bulk height was 0°38, and the sheet had excellent handling properties.

For comparison, the same treatment was carried out with a water pressure of 100 kg/cd and 70 mounds/d, but in the case of 100 kg/cd, the glass fibers were severely cut and a uniform sheet could not be obtained.
The bulk height has also been increased to 0.13, resulting in a bulkier seat. In addition, in the sheet treated at 70 kg/cd, although many broken glass fibers were observed, it was possible to obtain a substantially uniform sheet, but the sheet was still bulky and the Vfmax measured by the method of Example 2 is as low as 45vo1%, and 30
The value of the sheet of the invention method treated with kg/c+j is 62V
It was extremely inferior to O1%.

Example 4 Aromatic polyamide fiber yarn (
DuPont Kevlar49 T965 142
0 denier/1000 filament), water pressure 2
A reinforcing fiber sheet was prepared by processing at 0 kg/d.

T, /T, of the obtained reinforcing fiber sheet. was 630, the bulk height was 0.46, and the drapability was extremely high.

Example 5 and Comparative Example 2 The 150 glass fiber yarns used in Example 3 were aligned and taken out, arranged to have a width of 50 cm, and passed through a web manufacturing cutter (Converter TOK-3F, manufactured by Osaka Kiko Co., Ltd.). A bias cut of 51 m+ length was performed, and the sheet was directly cut into a sheet shape to obtain a sheet in which discontinuous fibers were arranged.

On the other hand, for comparison, a web sheet with a random fiber length direction was obtained using the same glass fiber with a fiber length of 51 mm using a roller card machine (Yamato Kiko type).

A reinforcing fiber sheet was created.

T o /T v of the obtained reinforcing fiber sheet. is 6
30, the bulk height was 0.46, and the drapability was extremely good.

Example 5 and Comparative Example 2 The yarns were taken out from the 150 glass fiber yarns used in Example 3, lined up so as to have a width of 50 mm, and cut using a cutter for web production (Converter TO manufactured by Osaka Kiko Co., Ltd.).
K-3, F), a 51-length bias cut was performed, and the sheet was taken off as it was to obtain a notebook in which discontinuous fibers were arranged.

On the other hand, for comparison, the same glass fibers with a fiber length of 51 were web sorted in a random fiber length direction using a roller card machine (Yamato Kiko type).

These two types of sheets were treated with a water stream (
A reinforcing fiber sheet was obtained by applying a water pressure of 30 kg/cd) in the same manner as in Example 1.

The properties of the obtained sheet and the properties of the fiber-reinforced molded product made in the same manner as in Example 2 are also listed in Table 3.

It was proved that the sheet of the present invention can obtain a high Vf and at the same time has excellent mechanical properties even in a molded article having the same Vf value.

(Effects of the Invention) As is clear from the above detailed description, the reinforcing fiber sheet of the present invention has fibers arranged, so when it is made into a fiber-reinforced resin material, it can have a high fiber volume ratio. In addition, since it has high mechanical properties and is in sheet form, processing operations are extremely simple, and processing efficiency or production efficiency is dramatically improved, and its industrial significance is extremely high. .

Further, in the method of the present invention, a sheet-like product can be efficiently formed at a relatively low pressure of 50 kg/ej or less.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus showing one embodiment for obtaining a reinforcing fiber sheet of the present invention. 1 is a net process for conveying the sheet, and the net 11 also serves as a porous support during liquid flow processing. Reference numeral 2 denotes a liquid jetting device including pores for jetting out a liquid jet. The pores are installed so that a liquid stream can be ejected perpendicularly to the surface of the net 11, and eject the liquid sent by a liquid sending means not shown in the figure. 3 is a suction box for liquid absorption, and is provided with a slit 31 for defining a liquid absorption zone! be done. The suction box 3 is depressurized by a drainage/exhaust device (not shown in the figure) to exert its liquid suction ability. 1 ・ ・ ・ ・ 2 ・ ・ ・ ・ 3 ・ ・ ・ ・ 11 ・ ・ ・ 31 ・ ・ ・ Net process, liquid jet jet device, suction box, net, slit,

Claims (5)

[Claims] (1) A sheet made of one or more of carbon fibers, glass fibers, and aramid fibers, in which the fibers are arranged substantially in the same fiber length direction, and in a preset area of the sheet. A sheet in which fibers are intertwined, and in this sheet, (i) tensile strength in the direction in which the fibers are arranged (T_0) and tensile strength in the direction perpendicular to this (T_0).
T_9_0) is 50≦T_0/T_9_0≦10
(ii) a reinforcing fiber sheet having a bulk density of 0.2 to 0.7, which is obtained by dividing the bulk density of the sheet by the density of the fibers constituting the sheet. (2) The reinforcing fiber sheet according to claim (1), wherein the fibers constituting the sheet are continuous long fibers. (3) The fibers constituting the sheet have a fiber length of at least 25
The reinforcing fiber sheet according to claim 1, which is a discontinuous fiber having a diameter of mm or more. (4) In a method for producing a nonwoven fiber sheet by applying a liquid flow to a fiber web, a fiber or a fiber bundle consisting of one or more types of carbon fiber, glass fiber, and aramid fiber is substantially The fibrous webs are arranged with their longitudinal directions aligned, and while absorbing liquid from the back side of the fibrous web through a porous support, a diameter A reinforcing fiber characterized by intertwining the fibers by applying at least one liquid stream having a pressure of 2 kg/cm^2 to 50 kg/cm^2 and jetting out from pores of 0.5 mm or less. Seat manufacturing method. (5) A reinforcing fiber sheet according to claim (4), wherein the fiber web arranged with the fiber length direction aligned is continuously supplied, a liquid stream is applied to intertwine the fibers, and then the sheet is continuously taken off. manufacturing method.