JPH08109566A - Nonwoven fabric as unidirectional reinforcing material and its production - Google Patents

Abstract

PURPOSE: To obtain a nonwoven fabric high in reinforcing effect, capable of producing molded forms with good surface smoothness, thus useful as a reinforcing material for fiber-reinforced composites, esp. printed wiring boards. CONSTITUTION: Short glass fibers 5-30mm in length are homogeneously dispersed in a dispersion 12 in a relevant tank 11 and fed to a papermaking machine 13 where a papermaking net 14 as a water-filterable base material is traveling continuously on a water filtration board 16. On the other hands, plural continuous glass fibers 32 sufficiently opened in advance are set, via a guide roller 33, on a fixed member 34 of the papermaking net 14, and on driving the papermaking machine 13, moved together with the papermaking net 14 in such a state as to be arranged planarly on the net 14, thereby forming a fibrous mat 15 having such a structure that 20-90 (pref. 60-85)wt.% of the continuous glass fibers 32 are packed in the short glass fibers. An excess of water is then removed from the mat 15 by using a suction device 17 and the resultant mat 15 is imparted with a binder 19 in a binder tank 20 using a spaying device 21 and then dried to bond the intersections of the short fibers and the continuous fibers 32, thus obtaining the objective nonwoven fabric for unidirectional reinforcement.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to synthetic resin, cement,
Non-woven fabric for a unidirectional reinforcing material used as a reinforcing material for a fiber reinforced composite material in which rubber or the like is reinforced with fibers, and in particular, a unidirectional material suitable for use as a reinforcing material for a fiber reinforced resin molding or a printed circuit board. TECHNICAL FIELD The present invention relates to a nonwoven fabric for reinforcing material and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, cloth, chopped strand mats, continuous strand mats (swirl mats), etc. have been used as forms of reinforcing materials for fiber-reinforced resin composite materials. In recent years, in order to maximize the effect of the reinforcing material, it has been demanded that the reinforcing material be unidirectionally reinforced, and the prepreg method has been adopted in recent years. That is, continuous fibers serving as a reinforcing material are aligned in one direction and in a plane, and the continuous fibers are dipped in a molten resin or a resin solution and then dried to form a prepreg, which is molded using this prepreg. By doing so, a molded body having a desired shape is produced.

However, the prepreg thus obtained has a problem in operation due to the shape of the continuous fiber as a reinforcing material being broken due to the orientation, and the continuous fibers arranged in one direction at the time of molding have intersections. Since it does not exist, there is a problem that the resin flows with the flow of the resin and it is difficult to maintain the characteristic one-way property. There is also a problem in that it is extremely difficult to shape the reinforcing material having only one direction in terms of fitting into the mold during molding.

Therefore, it is known that a large number of continuous fibers aligned in a plane are completely adhered to the surface of a chopped strand mat, which is a reinforcing material, by using an adhesive to completely adhere them. However, in order to ensure the adhesion of the continuous fiber to the chopped strand mat, many adhesives must be used, resulting in high cost and good performance by preventing smooth impregnation of the impregnated material in the post process. There is a problem that a composite material cannot be obtained. Further, since the chopped strand mat has a low density, it is difficult to increase the content rate of the reinforcing material when it is made into a composite material, and there is a problem that the reinforcing effect cannot be sufficiently exhibited.

On the other hand, a woven fabric of continuous fibers such as glass fibers is often used as a reinforcing material for printed circuit boards. This is because by using a woven fabric as a reinforcing material, it is possible to obtain a substrate having a high content of the reinforcing material, and since the reinforcing material is a continuous fiber, the mechanical properties (strength, dimensional stability, etc.) are improved. This is because an excellent substrate can be obtained.

However, when the woven fabric is used as the reinforcing material, the impregnation of the resin at the intersection of the warp yarn and the weft yarn of the base fabric is insufficient, and when heat is applied to the printed circuit board during the step of mounting on the printed circuit board, There is a problem that a small peeling may occur at the intersection point and a whitening phenomenon (measling) may occur. When such a peeling phenomenon occurs,
At the time of through-hole plating, the plating solution penetrates into this peeled part, causing circuit conduction in unnecessary parts,
It also affects the roughness of the inner wall of the through hole, so it must be prevented. Furthermore, when a woven fabric is used as a reinforcing material, the unevenness of the woven fabric appears on the surface of the substrate, resulting in poor surface smoothness.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art. The present invention has continuous fibers arranged in one direction and acting as a reinforcing material, and at the same time, the continuous fibers are formed by the flow of resin during molding. It is an object of the present invention to provide a non-woven fabric for a unidirectional reinforcing material, which can prevent the flow of water and has a good shapeability and a high reinforcing effect.

Further, when the present invention is used as a reinforcing material for a printed circuit board, the printed circuit board can be provided with necessary mechanical properties such as strength and dimensional stability and excellent surface smoothness, and further, peeling is possible. An object of the present invention is to provide a non-woven fabric for a unidirectional reinforcing material for a printed circuit board, which hardly causes a phenomenon.

Another object of the present invention is to provide a method for producing the above-mentioned nonwoven fabric for unidirectional reinforcing material.

[0010]

Means for Solving the Problems As a result of studies to solve the above-mentioned problems, the present inventors disperse short fibers acting as a reinforcing material for a composite material in a dispersion liquid, and disperse the short fibers in one direction. An upper layer, a lower layer, or a middle layer of continuous fibers for arranged reinforcement is deposited by a papermaking technique into a mat, and then,
A unidirectional flexible and high density consisting of continuous fibers arranged in one direction and short fibers entwined and joined to each other by adhering the intersection points of the mat-like short fibers and continuous fibers that contact each other with a binder. That a continuous non-woven fabric can be produced, and that when the obtained non-woven fabric is used as a reinforcing material for a resin composite material, the resin can be reinforced well with continuous fibers maintaining a unidirectional arrangement, and It has good shape and can be used to form a desired shape.
The present invention has been completed by finding that it can be preferably used for printed circuit boards.

That is, the present invention is a non-woven fabric composed of short fibers and continuous fibers which act as a reinforcing material for a fiber-reinforced composite material, wherein the short fibers dispersed in a dispersion are unidirectionally and planarly formed. It has a structure formed by depositing on the drainage base material together with the arranged continuous fibers, and maintains the sheet shape by bonding the intersection points of the short fibers and the continuous fibers which are in contact with each other with a binder. The non-woven fabric for unidirectional reinforcing material is characterized in that.

Further, according to the present invention, short fibers acting as a reinforcing material of the fiber-reinforced composite material are dispersed in a dispersion liquid,
A continuous fiber that acts as a reinforcing material of the fiber-reinforced composite material and is deposited on a drainage substrate together with a plurality of continuous fibers arranged in one direction and in a plane to form a fiber mat, and the fiber mat, A method for producing a nonwoven fabric for a unidirectional reinforcing material, characterized by uniformly impregnating a binder for cross-point adhesion between fibers, and then drying the reinforcing short fibers in a dispersion liquid, Depositing on a drainage substrate with a plurality of continuous reinforcing fibers arranged in one direction and in a plane to form a fiber mat, uniformly impregnating a binder for cross-point adhesion, and then drying. The gist is a method for producing a non-woven fabric for a unidirectional reinforcing material.

The present invention will be described in more detail below. The type of continuous fiber used in the nonwoven fabric for unidirectional reinforcing material of the present invention (hereinafter referred to as unidirectional nonwoven fabric or simply nonwoven fabric) is arbitrary as long as it acts as a reinforcing material of the fiber-reinforced composite material. Specific examples thereof include glass fiber, carbon fiber, alumina fiber, aramid fiber and the like, and desired fibers can be used alone or in combination depending on the application. For example, when the nonwoven fabric of the present invention is used for a printed circuit board, a material having no conductivity, that is, glass fiber,
Alumina fiber and aramid fiber are suitable. The continuous fiber used in the present invention is usually used in the form of a strand formed by bundling 200 to thousands of fibers having a fiber diameter of 6 to 30 μm. A large number of continuous fibers are held in parallel in a non-woven fabric in an array, and the pitch is usually about 0.5 to 2 mm. The strand used here is preferably one that has been sufficiently opened. This is because the resin impregnation at the time of molding becomes good, and the number of intersections between fibers increases, which is also advantageous for shape retention. The continuous fiber obtained by drawing a large number of fibers may be provided in only one layer in the nonwoven fabric, or may be provided in a plurality of layers. When only one layer of continuous fibers is provided, the layer of continuous fibers may be arranged on one side of the layer of short fibers, or a sandwich structure sandwiched between layers of short fibers may be used. It may be one.

The type of the short fibers which form the nonwoven fabric together with the continuous fibers is arbitrary as long as it acts as a reinforcing material of the fiber-reinforced composite material, like the above-mentioned continuous fibers, specifically, glass fiber, Carbon fiber, alumina fiber, aramid fiber and the like can be mentioned, and desired fibers can be used alone or in combination depending on the application. Further, the short fibers may be the same as the continuous fibers that together constitute the nonwoven fabric, or different types may be appropriately combined and used. Fiber diameter of these short fibers,
The length is not particularly limited, but the fiber diameter is 6 to 2
It is preferably 0 μm and has a length of about 5 to 30 mm in terms of production.

When the glass fiber is used as the continuous fiber and / or the short fiber, the glass fiber sizing agent is a surface treatment agent: 0.3 to 0.6 wt%, a lubricant: 0.1 to 0.3 wt%, a nonionic surface active agent. A sizing agent having a composition such as an agent of 0 to 0.5 wt% and an antistatic agent of 0 to 0.3 wt% is suitable. The adhesion rate is generally 0.1 to 1.0 wt%, and in the case of a printed circuit board,
It is 0.1 to 0.5 wt%. The adhesion rate of the sizing agent should be as low as possible, as long as it does not hinder the subsequent steps. If the attachment rate of the sizing agent can be reduced, not only the impregnation of the resin in the molding step is improved, but also the continuous fibers arranged in one direction can be opened only by passing through the paper making step in the production of the nonwoven fabric. As the surface treatment agent, aminosilane, methacrylsilane, epoxysilane, cationic silane, which are generally known as silane coupling agents, are used. In this case, the surface treatment agent also has an action as a focusing component. Therefore, it is also possible to add a synthetic resin adhesive component to the above composition as a focusing component.

The proportion of continuous fibers and short fibers for reinforcing material in the nonwoven fabric of the present invention is determined according to the purpose and application, but when used for general molding, 20 to 90 wt% is continuous fibers and the rest is short fibers. It is preferable that If the proportion of continuous fibers is less than 20 wt%, the reinforcing effect will be reduced, while if it exceeds 90 wt%, the short fibers will be too small and the effect of restricting the flow of continuous fibers during molding will be reduced. , The non-woven fabric becomes hard and the shapeability decreases. Therefore, the above range is preferable. Furthermore, when the nonwoven fabric of the present invention is used as a reinforcing material for a printed circuit board, 6
It is preferable that 0 to 85 wt% is a continuous fiber and the rest is a short fiber. A printed circuit board is required to have particularly high strength and dimensional stability, and is not required to have good shapeability. Therefore, it is preferable that the content of continuous fibers is large.
It is set to 0 wt% or more. On the other hand, short fibers also have the function of improving the surface smoothness of the molded product, and since surface smoothness is required for printed circuit boards, a certain amount of short fibers is necessary. It is set to 85% or less.

In the non-woven fabric of the present invention, as the kind of binder used for joining the intersections between the fibers, synthetic resin type emulsions such as epoxy type, polyester type, polyvinyl acetate type and polyacrylic acid ester type are used. A suspension is used. Especially for printed circuit boards,
Epoxy type and polyester type binders are preferable, and when the matrix resin is an epoxy resin, an epoxy type binder is suitable, and when it is a polyester resin, a polyester type binder is suitable. Adhesion rate is 10 to 15 wt% for general molding
Is preferable, and more preferably 10% or less. Also,
In the case of a printed circuit board, 5 to 10 wt% is preferable, and 7% or less is further preferable.

[0018] the weight per unit area of the nonwoven fabric of the present invention, when for general molding, 50 to 400 g / m ^2, when the printed circuit board, approximately 80~250g / m ² is preferred.

Next, the method of the present invention for producing the unidirectional nonwoven fabric of the present invention will be described in detail. A continuous fiber (for example, glass fiber) for reinforcing material having a fiber diameter of 6 to 20 μm is used as a short fiber having an appropriate length. The length of the short fibers at this time is 5 to
The length is preferably 30 mm, because the dispersibility when the short fibers are dispersed in the dispersion is good as described later.

Next, the short fibers are put into a dispersion, and the filaments are opened and dispersed with stirring. Here, as the dispersion liquid, a 0.1 to 0.3% aqueous solution using a commercially available dispersant Marpomerce PT or Sontes KV (both manufactured by Matsumoto Yushi Kogyo Co., Ltd.) is suitable. The dispersion concentration of the short fibers to be added to this is 0.02-0.2%, preferably 0.05-0.
1% is good.

The short fibers in this dispersion are then deposited on a drainage substrate using papermaking techniques to form a fiber mat. This step may be either a batch type or a continuous type, but a batch type using the paper machine shown in FIG. 1 will be described as an example. A paper machine indicated by reference numeral 1 as a whole is a paper machine main body 3 for containing a dispersion 2 and a hinge 4 for the paper machine main body 3.
Bottom rotatably held by, a fixing member 6 for fixing the paper machine body 3 to the bottom 5, a drainage base material 7 attached to the upper surface of the bottom 5, and a drainage pipe connected to the lower end of the bottom 5. 8 and a valve 9 and the like. The dispersion liquid 2 is put into the paper machine 1, and the valve 9 is opened and the liquid is discharged while the short fibers are uniformly dispersed in water. As a result, the introduced dispersion liquid 2 passes through the drainage base material 7, is discharged from the drainage pipe 8, and the short fibers are captured on the drainage base material 7. When the dispersion has almost completely passed through the drainage base material 7, a fiber mat composed of short fibers is uniformly formed on the drainage base material. Here, as the drainage base material 7 to be used, it is preferable to use a net having a large number of small meshes.

After forming the short fiber mat as described above, a large number of continuous fibers 31 such as glass fiber strands are arranged in one direction and in a plane on the aluminum frame 30 as shown in FIG. Then, the adhered one is placed, and the short fiber dispersion liquid is again charged into the paper machine 1 to form the short fiber mat layer again. As described above, it is possible to obtain a high-density fiber mat having a sandwich structure with continuous fibers in the middle. Next, this fiber mat is taken out, and after undergoing a dehydration step, a binder suitable for the purpose, such as epoxy type or polyester type, is applied and dried to bond the intersections between the fibers.
As a result, a unidirectional nonwoven fabric composed of reinforcing continuous fibers and short fibers can be obtained.

In the above steps, it is possible to omit the first papermaking step. By omitting the first papermaking step, one side is made of short fibers and the other is made of unidirectional continuous fibers. A non-woven fabric can be obtained. Also,
It is also possible to repeat the supply of continuous fibers and the paper making process a plurality of times, whereby it is possible to obtain a nonwoven fabric in which continuous fibers are arranged in multiple stages.

Although the method of the present invention has been described in the batch method using the apparatus of FIG. 1, the production method of the present invention is not necessarily limited to this, and can be carried out in a continuous method as shown in FIG. . That is, in FIG. 3, short fibers for reinforcing material are introduced and dispersed in the dispersion liquid 12 in the dispersion tank 11, and the dispersion liquid 12 is continuously supplied to the paper machine 13.
In the papermaking machine 13, a papermaking net 14 which is a drainage base material continuously runs on a drainage board 16 at the bottom thereof. On the other hand, as continuous fibers for a reinforcing material, a plurality of (several hundred) strands 32 of glass fiber or the like that have been sufficiently opened or divided into fine counts in advance in a dispersion liquid in the paper machine 13 via a guide roller 33. Through and papermaking net 14
It is set on the fixing member 34 attached to.

When the liquid level in the dispersion tank 11 reaches a certain level, the operation of the paper machine is started. That is, the papermaking net 14
Run continuously, and short fibers are continuously deposited thereon, and the strands 3 move as the papermaking net 14 moves.
2 also moves. As a result, the strands 32 are arranged on the papermaking net 15 in one direction, and the strands 32 are arranged.
A fiber mat 15 having a structure in which the short fiber is sandwiched is formed. The fiber mat 15 passes through a suction device 17 to remove excess water, then is transferred to an adjacent conveyor net 18, and the binder 19 in the binder tank 20 is sprayed from above by a spray device 21.
After that, the fiber mat 15 is sent to the dryer 22 and the intersections between the fibers are bonded. In this way, a unidirectional nonwoven fabric having a structure in which continuous fibers arranged in one direction are bonded with short fibers is formed.

[0026]

In the unidirectional nonwoven fabric of the present invention obtained by the above method, the short fibers dispersed in the dispersion are deposited on the drainage substrate together with the continuous fibers arranged in one direction and in a plane. By using the papermaking technique called
It has a structure in which fibers are accumulated at a high density and continuous fibers and short fibers are intertwined at their contact surfaces,
Only by adding a small amount of binder and joining the intersections of the fibers, the whole can be maintained in a sheet shape, and the fibers are less likely to fall off when cut into a desired size or bent. Therefore, it is easy to handle when it is used as a reinforcing material for a fiber-reinforced composite material.

The unidirectional nonwoven fabric of the present invention is also used as a reinforcing material for a fiber-reinforced composite material in the same manner as various conventional reinforcing materials.
For example, it is used as a molding material for a fiber-reinforced resin molding together with a thermosetting resin or a thermoplastic resin, and is particularly suitable as a molding material for a printed circuit board. Further, as a molding method, a conventionally known molding method may be appropriately adopted. For example,
In order to manufacture a printed circuit board using the unidirectional nonwoven fabric of the present invention, first, the unidirectional nonwoven fabric of the present invention is passed through a resin varnish bath to impregnate the resin varnish and dried to form a semi-cured resin. A printed board can be obtained by producing a prepreg, then laminating the prepreg, laminating a foil-forming metal such as an aluminum foil or a copper foil on one side or both sides, and thermocompression bonding. At this time, the continuous fibers of the prepreg to be laminated may be parallel to each other or may intersect with each other.

When a fiber-reinforced resin molded product is produced using the unidirectional nonwoven fabric of the present invention, resin flow occurs during resin impregnation or molding for preparing a prepreg, but the resin is unidirectionally arranged in the nonwoven fabric. The continuous fibers are in a state of being constrained by the irregularly arranged short fibers, so that the continuous fibers are less likely to be disturbed by the flow of the resin, and a molded body in which the continuous fibers are arranged in one direction is formed. Can be manufactured. Moreover, since the short fibers acting as a reinforcing material are arranged in an irregular direction in this non-woven fabric, this can exert a reinforcing effect in the direction perpendicular to the continuous fibers. Furthermore, since the nonwoven fabric of the present invention is manufactured using a papermaking technique, short fibers are dispersed in filaments and open fibers can be used as continuous fibers, so that the resin has a good resin impregnation property. Further, since it is made with high density, it is possible to form a resin molded body having a high content of the reinforcing material.

The resin molded body produced by using the unidirectional nonwoven fabric of the present invention has the following characteristics. That is, since the continuous fibers have good orientation, the strength is high and the dimensional stability is good. Further, when the short fiber layer is arranged on the surface, the smoothness due to the short fiber layer being arranged and the pressing effect being easily exhibited due to the fact that the short fiber layer is likely to contain the resin, the surface smoothness is good. . Furthermore, when used as a printed circuit board, a printed circuit board having good heat resistance can be obtained. A printed circuit board using a reinforcing fiber woven fabric as a reinforcing material has an intersection of continuous fibers, and impregnation at the intersection is likely to be insufficient. Is easily peeled off, and the part thereof is likely to be whitened. However, in the present invention, such whitening is unlikely to occur because there is no intersection of continuous fibers.

[0030]

【Example】

Example 1 Production of Glass Fiber E glass fiber (filament diameter 9 μm × 400 fibers) was spun, and a sizing agent having the following composition was applied and bundled. Surface treatment agent (epoxysilane) 0.4% Butyl stearate 0.1% Emulgen 911 0.2% (Nonionic surfactant Kao Corporation) Water residual adhesion rate was 0.3%.

The glass fiber obtained in the production of the unidirectional nonwoven fabric was cut into short fibers having a fiber length of 6 mm, and 1.0 g in water containing 0.1% of the dispersant Marpomerce PT (Matsumoto Yushi Kogyo Co., Ltd.) dissolved therein. Throw in, 0.2
% Dispersion was made. The glass fibers were dispersed in a filament shape by stirring. In addition, 30 glass fibers / glass fiber (22 cm × 22 cm) shown in FIG.
It was attached at a pitch of 25 mm to obtain a unidirectional continuous fiber sheet. This aluminum frame is set in the paper machine shown in FIG. 1, the dispersion liquid of glass fiber is charged from above, the valve 9 is opened, the dispersion liquid is drained through the drain pipe, and the drainage base 7
A fiber mat in which short fibers were deposited on a unidirectional continuous fiber sheet was obtained. The weight ratio of the short fibers in the fiber mat was 20%.

A binder having the following composition was applied to the fiber mat thus formed and dried. KE-002 (epoxy resin emulsion: made by Yoshimura Yuka Co., Ltd.) 20.0% E-1002 (epoxy resin emulsion: made by Yoshimura Yuka Co., Ltd.) 20.0% epoxysilane 0.3% By this, the intersection of the fibers Was bonded to obtain a unidirectional nonwoven fabric which was kept in a sheet form. The weight per unit area of the unidirectional nonwoven fabric was 107.5 g / m ² , and the binder adhesion rate was 7%.

As a comparative example, a glass cloth having the following specifications was prepared. WEA116E (manufactured by Nitto Boseki Co., Ltd.) Thread used Vertical ECE 225 1 / Horizontal ECE 225 1/0 Number of implants Vertical 60 / 25mm Horizontal 58 / 25mm Unit weight 105g / m ² Weave structure Plain weave Surface treatment Epoxysilane

The resin impregnating property of the glass cloth with the unidirectional nonwoven fabric obtained in the impregnating property test was tested. The above-mentioned unidirectional nonwoven fabric and glass cloth were simultaneously placed on an epoxy resin varnish (G-10 composition) whose viscosity was adjusted to 130 cps, and the time was measured until the resin was completely impregnated. The results were as follows. Time required for complete impregnation Unidirectional nonwoven fabric 3 minutes 25 seconds Glass cloth 14 minutes 30 seconds As is clear from these results, the unidirectional nonwoven fabric of this example is much more resin-impregnated than glass cloth. Was good.

The glass cloth with the unidirectional nonwoven fabric obtained in the production of the laminated plate was
An epoxy resin varnish having a composition of −10 was impregnated to prepare a prepreg. Five pieces of each of the prepregs were laminated, and a laminated plate was prepared by hot pressing. The laminated plate had a thickness of 0.5 mm and the resin content was 47% in each case. The composition of the G-10 composition is as follows: Epicoat 1001 (made by Yuka Shell Epoxy Co., Ltd.) 100 parts Epicoat 154 (made by Yuka Shell Epoxy Co., Ltd.) 20 parts Dicyandiamide 4 parts Benzyldimethylamine 0.2 parts Dimethylformamide 30 parts

Characteristics of Laminated Plate Surface Smoothness Measured in accordance with JIS B 0601 “Surface Roughness Measurement Method”. 60 points on the surface of the laminate were measured (measuring instrument: Kosaka Laboratory Ltd .: SEF-1A type). The results are as follows (unit: μm). min max Average unidirectional nonwoven fabric 2.6 5.1 3.8 Glass cloth 6.4 8.3 6.9 As is apparent from these results, the laminated plate using the unidirectional nonwoven fabric of this example is made of glass. The surface smoothness is far better than that of a laminated board using cloth, and thus it is a material suitable for a printed circuit board.

Solder heat resistance The laminated plate is pressure cooked (133 ° C),
After that, it was dipped in solder at 260 ° C. for 20 seconds, and the occurrence of measling on the surface was observed. The result is as follows. Pressure cooker Treatment time (min) 30 60 90 120 Unidirectional nonwoven fabric ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ △ Glass cloth ○ ○ ○ ○ ○ △ △ △ × × × × ○: No measling occurs △: Slight occurrence X: occurrence of measling ring As is clear from this result, the laminated plate using the unidirectional nonwoven fabric of this example is less likely to cause measling as compared to the laminated plate using the glass cloth, Therefore, it has excellent heat resistance. Therefore, it can be said that the material is suitable for a printed circuit board.

Example 2 A short glass fiber having a filament diameter of 13 μm and a fiber length of 6 mm (T-glass: manufactured by Nitto Boseki Co., Ltd.) was dissolved in water in which 0.1% of a dispersant, Marpomerce PT (manufactured by Matsumoto Yushi Kogyo Co., Ltd.) was dissolved. , 0.5 g was added to prepare a 0.1% dispersion liquid. On the other hand, as a continuous fiber, a glass fiber strand of 135 Tex (T-glass: manufactured by Nitto Boseki Co., Ltd.) was prepared, and this was formed into an aluminum frame (22 cm × 22 cm) shown in FIG.
17 pieces / 25 mm pitch were attached to each other to obtain a unidirectional continuous fiber sheet. This aluminum frame is set in the paper machine shown in FIG. 1, the glass fiber dispersion is charged from above, the valve 9 is opened, the dispersion is drained through a drain pipe, and the drainage substrate 7 is drained. A fiber mat in which short fibers were deposited on a unidirectional continuous fiber sheet was obtained. The weight ratio of the short fibers in the fiber mat was 10%. Then, the obtained fiber mat was coated with a binder and dried to obtain a unidirectional nonwoven fabric in which the intersections between the fibers were adhered and kept in a sheet form.

Example 3 As in Example 2, 0.7 g of glass short fibers were added to obtain a unidirectional nonwoven fabric having a short fiber weight ratio of 14%.

Example 4 The same as Example 2, except that 2 g of short glass fiber was added,
A unidirectional nonwoven fabric having a short fiber weight ratio of 30% was obtained. Using the unidirectional nonwoven fabrics obtained in the above Examples 2, 3 and 4, a prepreg having a resin weight ratio of 45% was prepared and a flat plate was molded (molding surface pressure 20 kg / cm ² ). Although a slight movement of the continuous fibers was observed in the direction orthogonal to the continuous fiber orientation direction, no disturbance in the orientation direction could be confirmed in Examples 3 and 4. Therefore, in any case, it could be confirmed that the fiber-reinforced resin molded product in which continuous fibers were well arranged in one direction could be molded.

[0041]

As described above, since the unidirectional nonwoven fabric of the present invention is composed of continuous fibers and short fibers which act as a reinforcing material of the fiber reinforced composite material, it can be a thermoplastic resin or a thermosetting resin. It can be suitably used as a molding material for a fiber-reinforced resin molding together with a resin, and during its molding, the continuous fibers are constrained by the short fibers so that they do not move. Without this, continuous fibers are arranged in one direction, and a molded body having a large reinforcing effect can be molded. Furthermore,
The unidirectional nonwoven fabric of the present invention employs a papermaking technique in which reinforcing short fibers dispersed in a dispersion liquid are deposited on a drainage base material together with continuous reinforcing fibers arranged in one direction and in a plane. Since it is manufactured by the above method, it has a high density and the entanglement of short fibers to continuous fibers is large, and the fibers are dispersed or opened, and the resin impregnation property is good. Therefore, the content of the reinforcing material is high. In addition, it has an effect that a resin molding having a large reinforcing effect can be formed. Furthermore,
By arranging the short fiber layer, it has an effect that the shapeability is good, molding into various shapes is easy, and a resin molding having high surface smoothness can be manufactured.

Thus, the unidirectional nonwoven fabric of the present invention is
It is possible to manufacture a molded article having a high reinforcing effect and a high surface smoothness, and since it does not have an intersection point of warp and weft like a woven fabric, there is no portion causing impregnation failure, and therefore heat treatment was performed. At that time, peeling and whitening hardly occur. Therefore,
The unidirectional nonwoven fabric of the present invention is particularly suitable for use as a printed circuit board, and also has an effect that a printed circuit board having excellent characteristics can be formed.

The production method of the present invention has an effect that the above-mentioned unidirectional nonwoven fabric can be produced.

[Brief description of drawings]

FIG. 1 shows one of the devices used to carry out the method of the invention.
Schematic cross section showing an example

FIG. 2 is a schematic perspective view showing a state where continuous fibers to be put into a nonwoven fabric are set in an aluminum frame.

FIG. 3 is a schematic side view showing another example of the apparatus used for carrying out the method of the present invention.

[Explanation of symbols]

 1 Paper Machine 2 Dispersion Liquid 3 Paper Machine Main Body 5 Bottom 7 Drainage Substrate 8 Drain Pipe 9 Valve 11 Dispersion Tank 12 Dispersion Liquid 13 Paper Machine 14 Paper Making Net 15 Fiber Mat 16 Draining Board 17 Suction Device 18 Conveyor Net 21 Spray Device 22 Dryer 30 Aluminum frame 31 Continuous fiber 32 Strand 33 Guide roller 34 Fixing member

Claims (4)

[Claims] 1. A non-woven fabric composed of short fibers and continuous fibers acting as a reinforcing material of a fiber-reinforced composite material, wherein the short fibers dispersed in a dispersion liquid are arranged in one direction and in a plane. It is characterized in that it has a structure formed by depositing it on a drainage substrate together with continuous fibers, and that the intersections of the short fibers and continuous fibers that are in contact with each other are adhered with a binder to maintain a sheet form. Non-woven fabric for unidirectional reinforcing material. 2. The ratio of the short fibers to the continuous fibers is 20.
The non-woven fabric for a unidirectional reinforcing material according to claim 1, wherein about 90 wt% is a continuous fiber and the rest is a short fiber. 3. The ratio of the short fibers to the continuous fibers is 60.
The non-woven fabric for a unidirectional reinforcing material according to claim 1, wherein about 85 wt% is continuous fiber and the rest is short fiber, which is used for a printed circuit board. 4. Short fibers acting as a reinforcing material of a fiber-reinforced composite material are dispersed in a dispersion liquid, and the continuous fibers acting as a reinforcing material of the fiber-reinforced composite material are unidirectionally and planarly formed. Depositing on a drainage substrate with a plurality of aligned continuous fibers to form a fiber mat, uniformly impregnating the fiber mat with a binder for cross-point adhesion between the fibers, and then drying. A method for producing a nonwoven fabric for a unidirectional reinforcing material characterized.