JPS59136223A - Reinforcing base for fibrous reinforcing resin - Google Patents

Abstract

PURPOSE:To obtain the titled base material suitable for preparing a fibrous reinforcing resin cylinder by stitching a hollow wound body obtained by winding a reinforcing fiber sheet piercing a sewing yarn having breaking elongation larger than the reinforcing fiber has in the direction approximately perpendicular to said wrapping surface. CONSTITUTION:Reinforcing sheets (such as sheets obtained by impregnating reinforcing fiber textile etc. with thermosetting resin such as unsaturated polyester resin, polyimide resin, etc.) 1, 2 are intersected preferably at right angles to each other and winding spirally to obtain a hollow wound body 4. Piercing through the wound body 4 a sewing yarn 3 of fiber with breaking ductility about 1.5 times as large as the reinforcing fiber forming said sheets at an angle between -15 deg. and +15 deg. to the perpendicular direction to the surface of the wound body 4, the hollow wound body 4 is sewed to provide a fiber reinforcing resin reinforcing bace 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a reinforcing base material for fiber-reinforced resins, and more particularly to a reinforcing base material for resins that is particularly suitable for molding pipe-shaped or ring-shaped M&dark blue reinforced resins.

Conventionally, pipe-shaped or ring-shaped fiber-reinforced resins (hereinafter referred to as FRP) have been manufactured by reinforcing them on a mandrel.
By rolling a rough prepreg sheet and applying pressure and heat to harden the resin, or by winding a reinforcing fiber fabric around a mandrel, impregnating the fabric with resin, and applying pressure and heat to harden the resin. Molded. however,
The FRP molded in this way is reinforced in the thickness direction! Since there are no l fibers at all, there was a drawback that the living room strength, particularly the interlaminar peel strength and interlaminar shear strength, was low.

On the other hand, Japanese Utility Model Publication No. 47-37027 discloses that, in a wound body formed by winding reinforcing fiber woven or non-woven fabric around a tubular mandrel, sewing thread having a strength greater than the reinforcing fibers constituting the woven fabric or non-woven fabric is attached to the mandrel. An FRP tube is described in which the tube is sequentially penetrated in the tangential direction, the wound body is then impregnated with a resin, and the resin is cured by applying pressure and heating.

In this FRP pipe as a whole, since threads are present in the thickness direction, the interlayer strength is improved compared to a pipe that does not use threads. However, the degree of improvement is so small that it hardly matters.

In other words, FRP has a large reinforcing effect in the direction of the II axis of the reinforcing fibers, but this effect rapidly decreases as it moves away from the fiber axis (at an angle to the fiber axis). It is a highly anisotropic material. In other words, when trying to improve the interlaminar strength of the FRP pipe as described above, it is most preferable to arrange the sewing thread in the radial direction of the pipe. However, in the above-mentioned conventional FRP pipe, the sewing thread passes through the mandrel in the tangential direction, so the sewing thread has a large angle with respect to the radial direction of the FRP pipe, and the properties such as strength and elastic modulus of the sewing thread are hardly affected. Therefore, the effect of improving interlaminar strength is small. However, if the sewing thread is made thicker or the sewing density is increased, the interlayer strength will increase in proportion.

However, in this case, the reinforcing fibers are cut or damaged when the suture is passed through, and the strength in the plane direction of the tube, that is, the in-plane strength, decreases, and the strength of the FRP tube as a whole is not so high. No. Also,
When a thick sewing thread is used, the arrangement of the reinforcing fibers is disturbed by the thread, resulting in a decrease in in-plane strength.

Damage to reinforcing fibers is likely to occur even when using thin sewing threads. That is, when the sewing thread is passed through the mandrel in the tangential direction one after another, at the sewing start end, the thread having a length equal to the length of the thread used for sewing passes through the wound body.・4J<, the closer it is to the sewing start edge, the more the sewing thread rubs against the reinforcing ta navy blue that makes up the woven or non-woven fabric, and the reinforcing fibers are more likely to be damaged.

Furthermore, if you try to pass the sewing thread sequentially in the tangential direction of the mandrel, you have to do it manually, which not only requires a lot of effort, but also makes it difficult to suture with uniform force, resulting in uneven wall thickness. However, there is also the drawback that the arrangement of the reinforcing fibers may be disordered, making it impossible to obtain a highly reliable FRP.

The purpose of the present invention is to solve the above-mentioned drawbacks of the prior art and provide a reinforcing base material that has high mechanical strength, especially interlaminar strength, and can easily produce pipe-shaped or ring-shaped FRP with high reliability. be.

To achieve the above object, the present invention provides a reinforcing base material formed by passing a sewing thread in the thickness direction of a hollow wound body formed by winding a sheet of reinforcement [1] and sewing the wound body. , the sewing thread is made of reinforcing fibers having a greater elongation at break than the reinforcing fibers constituting the sheet, and the sewing thread is at an angle of -15° to +156 with respect to the direction perpendicular to the surface of the wound body. To explain one embodiment of the reinforcing base material of the present invention, which is a reinforcing base material for fiber-reinforced resin characterized by having a penetrating structure, in FIG. 1 (schematic perspective view), a pipe-shaped The reinforcing base material 5 has a hollow wound body 4 formed by stacking sheets 1.2 of woven reinforcing fibers and winding them in a spiral shape. The woven fabric constituting the sheet 1 is arranged so that its warp is in the longitudinal direction of the reinforcing base material 5 (therefore, the weft is arranged at an angle of 900 with respect to the longitudinal direction), while The woven fabric constituting the sheet 2 is arranged so that its warp and weft are oriented at +45° and =45° with respect to the longitudinal direction, respectively. The winding start end and winding end of the fabric 1.2 are formed by reinforcing base material 5 at both ends.
1. They are slightly offset from each other to avoid creating significant unevenness.

A sewing thread 3 extends in the circumferential direction of the wound body 4 while repeatedly penetrating the wound body 4 from the inner surface to the outer surface and from the outer surface to the inner surface, and is attached to the reinforcing base material 5. They engage at equal pitches in the longitudinal direction to stitch together the wound body 4.

In the above, the sheet is not limited to fabric. It is also possible to use a so-called textile prepreg, which is a textile fabric impregnated with a thermosetting resin such as a B-stage epoxy resin, unsaturated polyester resin, phenol resin, or polyimide resin. That is, the sheet may be a prepreg sheet. In addition, the prepreg sheet is made of continuous reinforcing fibers.
It may be a so-called unidirectional prepreg made by aligning 1i miscellaneous materials in one direction in parallel to each other in a sheet shape.

The reinforcing fibers that make up the sheet are carbon fiber, glass 1
High-strength, high-elastic mH fibers such as iJi fibers, organic high-elastic fibers (eg, polyaramid fibers, etc.), and silicon carbide fibers. Different types of reinforcement for the same sheet
u may also be used.

For example, a mixed fabric of carbon fiber and glass fiber or a prepreg thereof can be used. The reinforcing fibers are usually made of multifilaments. The reinforcing fibers are used to improve resin impregnation when molding FRP, to increase the volume content in FRP, and to prevent cutting and damage caused by sewing threads when sewing the wound body. Therefore, it is preferable that the number of twists be as small as possible. In particular, when using carbon fiber, carbon fiber has an extremely high modulus of elasticity and low elongation at break.
Since it has the characteristic of being weak against bending force, it is preferable that it is substantially untwisted.

When using a woven fabric or its prepreg as a sheet, the woven structure may be any woven structure such as a plain weave, satin weave, or twill weave, but especially when it is desired to mold a thick F'RP, It is preferable to use satin fabric, which has a relatively thick thickness per sheet and a relatively low resistance to shearing, so there is less risk of cutting or damaging reinforcing fibers during sewing. In addition, as described in Japanese Patent Publication No. 57-52221, two groups of yarns made of straight reinforcing fibers with substantially no bends are drawn in a sheet shape approximately parallel to each other are used as auxiliary fibers. When using a so-called non-crimp fabric integrally woven by
Since l does not have bends where stress is concentrated, the characteristics of the reinforcing fibers are fully expressed, especially in the plane of the reinforcing base material, and an FRP with high in-plane strength can be obtained, which is preferable.

A single sheet may be wound in a spiral shape, or a plurality of sheets may be wound one on top of the other as shown in FIG. It is also possible to form further windings on top of the spiral winding. Further, the number of turns may be arbitrarily selected depending on the thickness of the FRP to be molded. However, if it becomes extremely thick, it becomes difficult to stitch with a sewing thread, so it is preferable to set the number of windings such that the thickness is 40111 m or less.

When winding sheets one on top of the other, reinforcement of each sheet i
The reinforcing fibers may be superimposed and wound so that they both face the same direction, and in some cases, the reinforcing fibers are oriented in the longitudinal direction of the reinforcing base material, and in some cases, the reinforcing fibers are oriented in the longitudinal direction. It is also possible to overlap and wind at different angles, such as at an angle. For example, the first
The angle combinations of 0°, ±1!15°, and 90° shown in the figure are suitable for obtaining in-plane pseudo-isotropic FRP. In addition, when emphasis is placed on torsional strength, all reinforcing fibers should be
Preferably, it should face in the direction of ±45°.

The sheets to be wound do not necessarily have to be made of the same type of reinforcing fibers. For example, a sheet made of carbon fiber and a sheet made of glass fiber can be overlapped and wound. In addition, first a spirally wound body is formed,
It is also possible to form a roll of another type of sheet on the top.

Furthermore, when stacking prepreg sheets and winding them, different types of prepreg sheets can be used in combination, such as using a woven prepreg and a unidirectional prepreg stacked together.

The sewing thread is used to sew the sheet rolls together and
It mainly improves the interlaminar strength when RP is molded. Such threads consist of multifilaments of reinforcing fibers similar to those making up the sheet. However, since the sewing thread is largely bent, the stress applied to the reinforcing base material will be concentrated at the bent portion. Therefore, in order to prevent the sewing thread from breaking before the reinforcing fibers that make up the sheet, thereby preventing further destruction of the reinforcing base material, the sewing thread is made larger than the reinforcing fibers that make up the sheet. Reinforcing fibers with breaking elongation are used as threads. The elongation at break is preferably 1.5 times or more greater than that of the reinforcing fibers constituting the sheet.

For example, when the sheet is made of carbon fiber, glass fiber or organic high-elastic fiber is suitable as the sewing thread.

It is preferable that the diameter of the single thread constituting the sewing thread is 3 to 15 μm. In particular, when the sewing thread is a glass fiber shoulder 1, the knot strength of the glass fiber is low, so it is preferably as thin as possible, preferably 7μ or less. When the sewing thread is made of organic highly elastic fibers, it is preferable to use threads with a single thread diameter of 10 to 15 μm for the same reason as above.

Further, the sewing thread preferably has a ply twist of 30 times/m or more in order to prevent single thread breakage and thread cracking during sewing. However, if the number of twists is too large, the shape of the cross section becomes round and the volume content of reinforcing fibers in the sheet when FRP is molded becomes low, so it is preferably 70 twists/m or less.

Roughly speaking, when the number of windings of the sheet is small, the thickness of the sewing thread is the same as the thickness of the reinforcing base material, and the above 1if of the FRP.
Since this will affect the t-volume content, it is preferable to use a thin material with a cross-sectional area of about 0.008 to 0.12 mm2 and to increase the sewing density. A more preferable cross-sectional area is 0.008 to 0.06 mm2. In addition, when the number of windings is large, approximately 5 times or more, the above-mentioned influence of the sewing thread is small.
5-0.3511 Im2, preferably 0.05-0.2
It is preferable to use a relatively thick thread of 5 mm2 and to lower the stitching density, since this will reduce damage to the reinforcing fibers during stitching.

The suture of the wound body with the suture is preferably carried out by single chain stitch or lock stitch in the sense that the suture does not easily come off. Most preferred is single chain stitch.

That is, in the single chain stitch, unlike the lock stitch in which the upper thread and the lower thread cross each other inside the wound body and are bent by 18 degrees, the thread does not bend inside the wound body.

Therefore, characteristics such as strength and elastic modulus of sewing thread can be fully utilized, and the effect of improving the interlayer strength of FRP is large. In order to express the characteristics of the sewing thread as it is and to effectively improve the interlayer strength of FRP, the sewing thread is adjusted at an angle of -15° to +15° with respect to the direction perpendicular to the surface of the wound body.
It must form an angle of °. Preferably it is 0°. In other words, FRP has the highest strength in the axial direction of the reinforcing fibers, so in order to improve the interlaminar strength, it is necessary to use sewing thread.
- It is necessary to penetrate at the specified angle.

If the stitching of the wound body with sewing thread is too strong, it may disturb the arrangement of the reinforcing fibers of the sheet, cause the subsequent resin impregnation to rotate, or cause resin pooling at the stitched portion when FRP is molded. If it is too weak, the sewing thread will loosen in the thickness direction when FRP is molded, and the interlayer strength will deteriorate.
Since the second effect is low, it is preferable that the thickness of the rolled body is approximately 0.9 to 1.1 times the thickness of the FRP molding.

In addition, if the sheet is particularly unidirectional blip-preg, the alignment of the reinforcing fibers is maintained only by the 8-stage thermosetting resin, so the alignment of the reinforcing fibers may be greatly disturbed during stitching. There is. J: In the case of eel, one or more thin fabrics made of the above-mentioned reinforcing fibers or nylon fibers, polyester fibers, rayon l fibers, vinylon fibers, etc. and having high shear resistance are attached to both the inner and outer surfaces of the wound body. It is best to overlap the sheets and sew them together.

Since the reinforcing effect in the circumferential direction is improved, the sewing thread preferably extends in a ring shape in the circumferential direction of the reinforcing base material as shown in FIG. They may be arranged as shown.

In the longitudinal direction, they may be arranged at equal pitches or completely randomly.

In the first embodiment, the case where the reinforcing base material is in the shape of a pipe with the same thickness has been described, but the reinforcing base material of the present invention can have various shapes.

For example, the shape may be a ring shape, a circular ring shape as shown in FIG. 2, a modified pipe shape as shown in FIG. 3, or the like. Further, by partially changing the number of windings of the sheet, it is possible to form a ring shape or a pipe shape in which only a specific portion in the longitudinal direction is thick, as shown in FIG. Furthermore, by inserting sheet pieces only in specific portions when winding the sheet, it is possible to obtain a reinforcing base material that is thick only in specific portions in the circumferential direction, as shown in FIG. Note that the cross-sectional shape of the reinforcing base material does not have to be circular as shown in FIGS. 1 to 5, and may be rectangular or other shapes.

The base material of the present invention is manufactured, for example, as follows.

In other words, a reinforced m-fiber sheet, a prepreg sheet thereof, or a sheet of these stacked together so that the reinforcing fibers are oriented in a desired direction is placed on an integrated or splittable mandrel-like core body having a desired cross-sectional shape. The core is wound a desired number of times, the core is pulled out, and a sewing thread threaded through a needle is passed through the core using a sewing machine to sew it. A core body having a slit in the sewing direction may be used, and the core body may be removed after sewing is performed at the slit portion. Further, when the sheet is a prepreg, it is preferable to apply a mold release agent such as silicone to the core to make it easier to remove the core. Furthermore, in the case of prepreg, the reinforcing fibers are difficult to move due to the B-stage thermosetting resin, and when the needle penetrates, the reinforcing fibers in an area corresponding to the cross-sectional area are cut or damaged. Because of this possibility, it is recommended to heat the prepreg and/or needle below the gelling temperature of the thermosetting resin to lower the viscosity of the resin and make the reinforcing fibers easier to move. In addition, if the sewing thread is impregnated with the same thermosetting resin as prepreg and made into prepreg, it will make sewing a little more difficult, but it will make the resin distribution more uniform when FRP is molded. , and voids are reduced, making it possible to obtain a stronger F'RP.

For molding of FRP using the reinforcing base material of the present invention, an integral or splittable mandrel with the desired cross-sectional shape is used. If the sheet is not a prepreg, the reinforcing base material is fitted into the mandrel and resin injection is performed. This is done using laws, etc. In addition, if the sheet is prepreg, the reinforcing base material is fitted into a mandrel and molded using an autoclave method, or the so-called tape wrapping method, which involves wrapping a heat-shrinkable film around the outer circumferential surface and heating it, is used. do.

As explained above, the reinforcing base material of the present invention (or the reinforcing fiber sheet) is sewn together with a hollow wound body formed by winding a reinforcing fiber sheet. against 11
Since it penetrates at an angle of 5° to +15°, it is possible to express the properties of the sewing thread such as strength and elastic modulus as is, and it is possible to express the properties of the sewing thread as it is, such as the strength and elastic modulus. However, since the 74i strong W IJ of the present invention uses reinforcing fibers having a higher breaking elongation than the reinforcing fibers constituting the sheet as sewing thread, (to do) supplementary bow f
Since the sewing thread does not break prior to f141 If, and the properties of the reinforcing fibers of the sheet can be utilized almost as they are, the in-plane strength of FRPk using this is also extremely high. In addition, the characteristics of sewing thread can be used to reduce its thickness.
There is less risk of cutting or damaging the reinforcing fibers that make up the sheet during stitching, further improving the in-plane strength of BSS and FRP. Furthermore, since the stitching of each winding can be performed using a sewing machine or the like, and there is no need for manual labor, manufacturing is not only simple, but also the stitching force of the wound body is uniform, resulting in highly reliable FRP. be able to.

The reinforcing base material of the present invention can be used when molding FRP for various uses, but it has high mechanical strength, especially interlaminar peel strength and interlaminar shear strength, and highly reliable FRP.
Since RP can be obtained, it can be used, for example, in pipes as primary structural materials for aerospace, mechanical elements, propeller shafts, wheels, rims of automobiles, motorcycles, bicycles, etc.
It is particularly suitable for molding pressure vessels, various high-speed rotating bodies such as centrifugal rotary cylinders, seal rings, and the like.

[Brief explanation of the drawing]

FIG. 1 is a schematic perspective view showing one embodiment of the reinforcing base material of the present invention, and FIGS. 2 to 5 are schematic perspective views showing different embodiments of the reinforcing base material of the present invention from the above-mentioned FIG. 1. FIG. 1.2: Reinforcing fiber sheet 3: Sewing thread 4: Wound body 5: Reinforcing base patent applicant Toshi Co., Ltd. Figure 2 Figure 3 Figure 4 Figure 5-13:

Claims (1)

[Claims] A reinforcing base material made by passing a sewing thread in the thickness direction of a hollow wound body formed by winding a sheet of reinforcing fibers, and sewing the wound body, the sewing thread being the reinforcing fibers constituting the sheet. is made of reinforcing fibers having a breaking elongation greater than
U characterized by penetrating at an angle of ″~+15°
&Reinforcement base material for fiber-reinforced resin.