JP2585165B2 - Method for producing flexible composite twisted tensile strength strip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a flexible composite stranded type tensile strength strip suitable for reinforcing members constituting a structure and for supporting a structure under tension. .

[0002]

2. Description of the Related Art Reinforcing bars and steel strands are widely used as tensile strength reinforcing members in civil engineering and construction. In recent years, high-strength, low-elongation fibers are impregnated with a thermosetting resin or the like, cured and molded. Composite tensile strength materials having various cross-sectional shapes have been developed. These composite tensile strength strips have tensile strength and tensile elasticity comparable to steel strands, and are lightweight,
It has excellent properties such as corrosion resistance and non-magnetic properties. Used for applications. There are two types of composite tensile strength strips, a non-twisted type and a twisted type. However, since the structure of each type cannot be changed after the resin is cured, a step of shaping into a predetermined sectional shape Alternatively, the braiding or twisting step needs to be performed simultaneously with or before the resin curing step.

For example, when a rod-shaped tensile strength member is obtained as a typical example of the former, the fiber is impregnated with the resin by a method such as guiding and immersing a fiber bundle in a resin tank, and then using a die or the like. A method is adopted in which the amount of the impregnated resin is adjusted by heating, and the wrung resin-impregnated fiber bundle is guided to a heated mold to simultaneously perform shaping and resin curing. In the latter, the fiber is braided or twisted and then impregnated with a resin, or the resin is impregnated and then braided or twisted in an uncured state to form a predetermined structure and then finally heat treated. A method of curing the resin in the process is used. These are disclosed in JP-B-57-25679 and JP-B-62-18.
No. 679.

[0004]

In this case, if the fibers are exposed on the surface of the composite tensile strength strip, the fibers are chemically degraded, or the fibers are easily fluffed by rubbing. Or reduce the mechanical properties. Therefore, by adjusting the amount of impregnated resin and further applying resin as needed, the surface of the composite tensile strength strip and the linear elements constituting the same are more or less covered with the resin layer. Then, since the heat treatment is finally performed in a state where the resin layer is present on the surface, the resin is cured while the adjacent composite tensile strength element is adhered. Accordingly, not only in the case of the rod type, but also in the case of a stranded type structure such as a braid or a stranded body, there is no freedom of movement between the composite filaments, and the flexibility was low similarly to the rod type. In particular, since high-strength, low-elongation fibers are used, elongation of the fibers themselves cannot be expected. Therefore, they have extremely high bending rigidity and have a so-called rod-like property.

[0005] Such high rigidity has caused the following problems. That is, if the diameter of the composite tensile strength strip is small, it can be wound into a coil diameter of about 1 to 2 m, but the diameter of the composite tensile strength strip is 10 to 15 mm.
If it is larger than this, it is necessary to make the coil diameter as large as several meters in order to wind it, which hinders conveyance. As a countermeasure, if the vehicle is cut with the length of the carrier as the upper limit, it can be transported in a bundled form, but use with a strip length exceeding this length is restricted,
The original property of continuity cannot be used well. In addition, because of its poor flexibility, there is no problem using it in a straight line.However, it is applicable to tensioning in a curved state, such as insertion into a pipe buried in a curve inside a concrete member or underground. It will be difficult to do. In addition, the rebound force from the coil increases due to the large diameter of the composite tensile strength strip, and if the coil end is accidentally released, the worker will be in danger due to the strong rebounding force of the coil. There was a problem in terms of aspects.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a low bending rigidity, a high flexibility, a synergy with a light weight, and a transportability and handling. It can be easily inserted into a pipe buried in a curved shape inside a concrete member or underground, etc., and can be effectively used for tensioning in the curved state. An object of the present invention is to provide a method for easily, efficiently and inexpensively producing a composite twisted tensile strength strip.

[0007]

In order to achieve the above-mentioned object, the present invention provides a method for twisting a plurality of composite filaments obtained by impregnating a high-strength low-elongation fiber with a thermosetting resin, followed by heat treatment. After the curable resin is cured to obtain a composite tensile strength strip, the composite tensile strength strip is guided to an adhesive breaking device equipped with a grooved roll, and the composite tensile strength is applied by the grooved roll while running the composite tensile strength strip. By repeatedly applying a bending and twisting action to the striated body, the adhesive resin layer that bonds the composite striated bodies to each other is sheared and broken.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIGS. 1 and 2 show an example of a flexible composite twist type tensile strength strip obtained according to the present invention. A is a composite twisted tensile strand, 1 is a core composite filament, and 2 is a plurality of side composite filaments arranged and twisted around the core composite filament. In this example, One composite striatum 1 for the heart,
The number of the side composite filaments 2 is six, which is a 1 × 7 structure. Each of the core composite filament 1 and the side composite filament 2 is obtained by impregnating a large number of high-strength low elongation fibers a with a thermosetting resin b and providing a coating layer c on the outer periphery. Has become
The core composite filament 1 and the side composite filament 2 are subjected to heat treatment in a twisted state, and the impregnated resin is cured.

However, the state at this time is as shown in FIG. 3, and the adjacent area between the composite striatum 1 for the heart and the composite striated body 2 for the side, and the adjacent area between the composite striated bodies 2 for the side are mutually Each is adhered by a thin resin layer b 'which oozes out on the surface of the coating layer c. For this reason, the flexibility of the composite tensile strength strip was low. Such a state is obtained for the following reason. That is, in the heat treatment process as described above, the viscosity of the impregnated thermosetting resin decreases to about several tens poise before curing, and the liquid becomes a liquid having fluidity. For this reason, it penetrates into the coating layer c by a capillary phenomenon, and eventually reaches the surface thereof and is cured while forming a resin layer on the surface layer. At this time, the resins between the composite filaments adhere to each other. The amount of resin on this surface can be adjusted by changing the amount of resin impregnation or the tension of the coating material in the coating process, but at least a surface resin layer that does not expose the coating layer c is intentionally formed. Therefore, the bonding phenomenon was inevitable.

FIG. 2 shows a composite twisted tensile strength strip according to the present invention, in which there is no thermosetting resin layer as an adhesive portion. And the adjacent area between the side composite filaments 2 are in frictional contact with each other only in a predetermined twisted form, and the composite filaments are slidable with each other. The bending stiffness of the strip A is substantially equal to the sum of the bending stiffnesses of the composite filament 1 for the core and the composite filament 2 for the side.

As the high-strength low-elongation fiber a, carbon fiber, silicon carbide fiber, aramid fiber, glass fiber, polyvinyl alcohol fiber and the like are used. As the thermosetting resin b, an epoxy resin, a polyimide resin, or the like is used. The covering layer c is preferably wound with fibers, but may alternatively be wound with a porous tape typified by a woven fabric or a non-woven fabric. Fibers such as polyester, polyamide, and aramid can be used as these coating materials. Further, the coating layer c may be a braided body made of the above-mentioned material.

The present invention describes a method for producing the above-described composite twisted tensile strength strip. First, the composite striated body for heart 1 and the composite striated body for side 2 are obtained. Next, at least one of the composite filaments is used as a core composite filament 1, and a side composite filament 2 is disposed around the composite filament 1 and twisted at a predetermined pitch. Get. Next, the composite stranded body is subjected to heat treatment, so that the composite composite filament for core 1 and the composite composite filament for side 2 are heat-treated.
The uncured or semi-cured thermosetting resin impregnated in the resin is completely cured to obtain a composite twisted tensile strength strip A ′. Then, the present invention further provides a composite composite filament 1 for the core and a composite composite filament 2 for the side which constitute the composite by mechanically bending or twisting the composite stranded type tensile strength filament A '. This is for mechanically destroying the resin layer b 'bonding between the side and side composite filaments 2.

Here, the steps up to obtaining the composite twist type tensile strength strip A 'are optional, and in particular, the method of obtaining the composite core filament 1 and the side composite filament 2 is optional. For example, the fiber core may be formed by twisting or braiding the high-strength low-elongation fiber a, impregnating the fiber core with a thermosetting resin, then coating the outer periphery with a dry powder agent, and applying a coating layer on the outer periphery. .
Alternatively, a filament bundle of high-strength low-elongation fiber a is impregnated with a thermosetting resin b.
A plurality of (semi-cured) strands may be twisted, and a coating layer c may be applied to the outer periphery thereof to obtain the composite filaments 1 and 2. In detail, the latter method is as follows. A filament bundle in which high-strength low-elongation fibers are aligned in parallel is pulled out from a reel, passed through a thermosetting resin bath, and impregnated to form a prepreg. Then, the prepreg is introduced into a shaping die to adjust the amount of resin impregnation and to shape the cross-sectional shape of the prepreg. Next, the prepreg is passed through a drying furnace and dried for a short time under the condition of, for example, 100 ° C. × 5 minutes, so that the thermosetting resin is semi-cured and wound on a reel. Next, a predetermined number of reels wound with the prepreg were mounted on the stand of the twisting device, the prepreg in which the thermosetting resin was in a semi-cured state was pulled out from each reel, passed between a pair of joining rolls, and disposed downstream. All the prepregs are rotated while being wound together on a reel, and thereby twisted at a predetermined pitch. The composite strand thus obtained is then drawn from a reel and coated while being wound on another reel via a guide roller. If the material is fiber or tape, the winding machine is arranged in the movement path, and the winding machine is swung around the composite twisted body while unwinding the coating material, and is perpendicular to the axial direction of the composite twisted body. The coating material is wound closely at a close angle. In addition, you may implement a coating process in the process of twisting a prepreg.

The composite filaments 1 and 2 thus obtained are wound on reels 10 and 20 as shown in FIG. 4, and the reels 10 and 20 are mounted on the twisting device 4 to form a composite filament. By being twisted at a predetermined twist angle in the direction opposite to the twist direction of 1, 2, a composite twisted body 3 such as 1 × 7 is wound on a reel 21. Then, as shown in FIG. 5, the reel 21 is disposed in the heat treatment apparatus 5, and the composite twisted body 3 is
1 and passed through a heat treatment apparatus 5. Thereby, the composite twisted body 3 is heated, and the semi-cured thermosetting resin impregnating the composite filaments 1 and 2 is completely cured,
It becomes a composite twist type tensile strength strip A '. The heat treatment condition is 1
One-stage processing such as 90 minutes at 30 ° C. may be performed, or multi-stage processing may be performed at about 100 ° C. for a predetermined time, for example, one hour, and at about 130 ° C. for a predetermined time, for example, one hour.

The composite twist type tensile strength strip A 'is a heat treatment apparatus 5
After passing through the reel 22, the present invention,
An adhesive breaking device 6 is provided in the line before being wound on the reel 22 or an adhesive breaking device 6 is provided in another line after being wound on the reel 22 so that each adjacent composite filament This is to forcibly destroy the thin resin layer b 'which has oozed and joined to the surface of the coating layer c of the bodies 1 and 2. It is preferable that the treatment by the bonding unit breaking device 6 is not performed suddenly at once, but is performed gradually several times.
Damage to the composite tensile strength strip and reduction in mechanical properties such as cutting load can be avoided.

FIGS. 6 to 8 show a first embodiment of the bonded portion breaking device 6 and a processing state by the device. In the first embodiment, the adhesion breaking device 6 is of a roll type. More specifically, as shown in FIG.
The first rolls 60a, 60b, 6 each have a groove 600 having a diameter equal to or close to the diameter of the first and second rolls, and having a structure in which the groove bottom diameter D is substantially the same as the twist pitch of the composite twisted tensile strip A '.
As shown in FIG. 6, a plurality (four in this example) of 0c and 60d are arranged in series in the longitudinal direction for an interval L of about 2 to 3 times the twist pitch of the composite twist type tensile strength strip, Second rolls 61a, 61b, 61c, 61 of the same specification
d, 61e to the first rolls 60a, 60b, 60c,
A plurality (five in this example) are arranged in series with a phase shift in the longitudinal direction from 60d. The interval L is 2 of the twist pitch
The reason for setting the roll diameter to approximately three times is to make the torsion work effectively at the same time as the bending. It must be. The first roll 60a,
60b, 60c, 60d and second rolls 61a, 61b,
The roll pair consisting of 61c, 61d and 61e is shown in FIG.
May be arranged on the same horizontal plane as shown in FIG. 7, or as shown in FIG. 7B, a plurality of pairs of rolls 62 composed of the first roll and the second roll are arranged in series and the bending directions are vertical and horizontal. May be arranged alternately in the two directions. In some cases, the axes of the rolls may be sequentially deflected as shown in FIGS. 7 (c) and 7 (d).

7 (a) and 7 (b), the first and second rolls 60a and 61a, 60b and 61b, 60c of each pair are shown.
And 61d, and 60d and 61d, the pulling force is adjusted by adjusting the roll interval W. FIG.
(c) and (d) are realized by adjusting the interval between the deflecting rolls. In this case, in order to prevent an excessive lateral pressure from acting on each of the composite filaments 1 and 2 of the composite twisted tensile strength strand A ′,
Roll spacing W is not uniform, and entry side shaft spacing W is large
(The drawing force is gentle), and it is preferable that the axial distance W on the output side is relatively small (the drawing force is large). Under this condition, the composite twisted tensile strength strip A ′ is slowly and uniformly formed. It pulls out at a good speed. This roll interval W
Can be varied linearly, for example, by linearly changing all the rolls, or by changing two rolls on the entrance side and two rolls on the outlet side. According to the first embodiment, the composite stranded type tensile strength strip A 'is pulled out while being alternately forcibly bent upward and downward in FIG. 6 with the groove 600 of each pair of rolls as a fulcrum. As a result, the composite strands 1 and 2 constituting the composite twisted tensile strength strip A 'are subjected to bending stress and also generate torsional stress due to the twisted structure. Since such a combined stress of the bending component and the torsion component is repeatedly applied by a plurality of pairs of rolls, as shown in FIG. Since the shear stress is effectively applied, and the composite stress increases toward the downstream, the adhesive resin layer b ′ is surely shear-ruptured, and as shown in FIG. 2 is an independent form of a composite twisted tensile strength strip A.

Next, FIG. 9 to FIG. 11 show a second embodiment of the bonded portion breaking device 6 of the present invention and the processing by the device.
In this embodiment, two parallel first roll shafts 62 are provided.
a and a plurality of first rolls 60a to 60e and second rolls 61a to 61 of which diameters are changed stepwise on the second roll shaft 62b.
e, each roll 60a-6
0e and 61a to 61e can rotate independently. The number of rolls is five in this example, but is not limited to this, and may be more or less. As shown in FIG. 10, each of the rolls 60a to 60e and 61a to 61e has a groove 600 having the same diameter as or similar to the diameter of the composite twisted tensile strength strip A 'on the body surface.
And the groove bottom diameter D is at least 33 times the diameter of the composite twisted tensile strength strip A ′. The reason is that, since the allowable compressive strain of the composite strand of the composite twisted tensile strip is about 1%, in the case of the composite twisted tensile strip of the seven-stranded configuration,
This is because, in order for the bending strain of the composite filament to be 1% or less, the relationship (d / 3) D ≦ 0.01 is specified. The groove bottom diameter D is defined as roll 60a ≒ roll 61e, and rolls 61a>60a>61b>60b>61c> 60c
>61d>60d> 61e.

The composite stranded type tensile strength strip A 'is shown in FIGS.
As shown in the figure, the roll 61a is wound half a turn from above and guided upward from the bottom to the left to reach the roll 60a. , And then roll 60 upward from the bottom to the left.
The rolls 60e are sequentially wound around a small-diameter roll in such a manner as to be guided to b, and finally pulled out in parallel with the incoming line direction via the left half circumference of the roll 60e. At this time,
The composite twist type tensile strength strip A 'is slowly and at a uniform speed so that the tension on the pull side is slightly higher than the tension on the feed side.
Is sent. In this way, the composite stranded type tensile strength strip A 'is mechanically subjected to the combined action of the bending component and the torsion component, and adheres the adjacent areas of the composite filament strips 1 and 2 as described above. Shear stress is effectively applied to the resin layer b ', and the adhesive resin layer b' is surely broken by shearing. Since the number of rolls is large and the roll diameter is gradually reduced, the bond between the composite filaments is gradually peeled off without damaging the composite twisted tensile strength strip A, and flexibility is imparted. The composite twist type tensile strength strip A can be obtained.

In both the first embodiment and the second embodiment, since the treatment by the roll is gradually performed a plurality of times, damage such as crushing or buckling of the composite twist type tensile strength strip due to lateral pressure does not occur, and the machine such as cutting load is not generated. Characteristic can be maintained. In the first embodiment and the second embodiment, if the roll is made of metal such as steel, plastic or rubber,
It is effective in preventing damage due to surface pressure. In addition, since it is a roll type, there is an advantage that the destruction of the bonded portion can be continuously performed in-line.

Next, specific examples of the present invention will be described. [Specific Example 1] An epoxy resin is impregnated into a carbon fiber multifilament having a diameter of 7 μm and a number of filaments of 12,000 aligned in parallel, adjusted to a resin impregnation amount of 35% by weight with a shaping die, and heated at 100 ° C. for 5 minutes. The prepreg was dried in a semi-cured state under the conditions to form a prepreg. Two prepregs were twisted, and then a 4000 denier multifilament polyester fiber was densely wound around the outer periphery and coated to obtain a composite filament. Using this composite filament, six filaments were arranged around the core and twisted at a pitch of 60 mm. this,
The epoxy resin is cured by heat treatment in an atmosphere of 100 ° C. for 1 hour and further at 130 ° C. for 1 hour, and a 1 × 7 with an outer diameter of 5.0 mm
A tensile strength strip having a structure was obtained.

Next, the composite tensile strength strip was guided to a steel roll pair as shown in FIG. Each roll surface has a groove of 2R = 5 mm having the same diameter as the diameter R of the tensile strength strip, and a groove bottom diameter.
(D) is 50 mm. The rolls were fixed at 90 mm intervals in the longitudinal direction, and the pulling force was adjusted to 6 kgf to 10 kgf by adjusting the roll interval between the first roll and the second roll. As shown in FIG. 7 (b), four sets of these roll pairs are arranged in series and arranged so that the bending direction alternates in a vertical direction and a horizontal direction. 6 kgf, and the two roll pairs on the delivery side were pulled out slowly at a uniform speed with a pulling force of 10 kgf.

In order to evaluate the flexibility, a test piece having a length of 50 cm was sampled, and the flexural rigidity EI was measured by applying the relationship between the load and the deflection of a simple beam by the two-point support center point loading method. As a result, the flexural rigidity of the composite tensile strength strip before the roll treatment was 810 kgf · cm ² , whereas that of the composite tensile strength strip was 122 kgf · cm ² . That is, in terms of the bending stiffness ratio, the flexibility was improved 6.6 times by the roll treatment. Only the 1.7-mm diameter core strand (composite composite filament) constituting the composite tensile strength strip was taken out and its bending rigidity was measured to be 17 kgf · cm ² . That is, the bending stiffness of the rolled product is
Since the bending stiffness of the composite filament is 7.1 times, the bending stiffness of the rolled one is almost equal to the sum of the bending stiffnesses of the seven composite filaments constituting the composite filament. It is clear that was effectively peeled off.

In order to examine the presence or absence of damage due to the roll treatment, a 1.6 m long test piece was sampled, fixed at both ends, and subjected to a tensile test. As a result, the cutting load of the composite tensile strength strip before the roll treatment was 2,100 kgf, and that of the composite tensile strength strip was 2,080 kgf. That is, the cutting load did not decrease even after the roll treatment. In addition, there was no change in the elastic modulus of both. In addition, all four roll pairs were adjusted to have a pulling force of 10 kgf and then subjected to roll processing. In this case, the flexibility was improved as described above, but the cutting load was 1900 kgf,
About 10% reduction in strength was observed. This is due to the fact that excessive lateral pressure was applied to the composite striated body of the composite tensile strength body that was in contact with the roll in the pair of rolls on the entrance side, and therefore, the roll processing conditions in which the entrance side was moderated It can be said that it is preferable to make

[Specific Example 2] Twenty-five prepregs of Specific Example 1 were twisted, and 8
A 2,000-denier multifilament polyester fiber was tightly wound and covered to form a composite filament. Using this composite striatum, one is placed in the center and six are placed around it,
They were twisted at a pitch of 150 mm. This was heat-treated in a 100 ° C. atmosphere for 1 hour and further at 130 ° C. for 1 hour to cure the epoxy resin, thereby obtaining a tensile strength body having an outer diameter of 12.5 mm and having a twisted structure.

Next, the composite tensile strength strip was guided to a pair of steel rolls as shown in FIGS. In this roll pair, several rolls having different roll diameters are installed in parallel on two shafts with an interval of L = 1,600 mm. 2R with the same diameter as the composite tensile strip on the roll surface
= 12.5 mm groove. As shown in FIGS. 9 and 11, the composite tensile strength strip was crossed and wound around a roll. At this time, the order of the rolls to be wound is set so that the groove bottom diameter is 8
50 mm (61a in FIG. 9)
(60a in FIG. 9), 700 mm (61b in FIG. 9), 650 mm (FIG.
60b), 600 mm (61c in FIG. 9), 550 mm (60c in FIG. 9),
500 mm (61d in FIG. 9), 470 mm (60d in FIG. 9), 440
mm (61e in FIG. 9) and 850 mm (60e in FIG. 9). By making the tension on the pull side slightly higher than the tension on the feed side, the roll processing was performed slowly and at a uniform speed.

Before the roll treatment, the composite high-strength filaments are bonded to each other with the epoxy resin on the surface of the composite filaments as in the first embodiment.
It was 16000 kgf · cm ² . On the other hand, what was rolled was 6500 kgf · cm ² . The cutting load was 16 000 kgf before the roll treatment, whereas the cutting load was 16100 kgf before the roll treatment.
f. Therefore, no reduction in strength due to the roll treatment was observed. The elastic modulus of both is 14
000 kgf / mm ² , and no difference was observed.
Only the core composite filament having a diameter of 4.2 mm constituting the composite tensile filament was taken out, and its bending rigidity was measured to be 1000 kgf · cm ² . Accordingly, the bending stiffness of the untreated roll is 16 times the bending stiffness of the core composite filament, whereas the bending stiffness of the rolled one is 6.5 times that of the core composite filament. is there. That is, the bending stiffness of the rolled material is substantially equal to the sum of the bending stiffnesses of the seven composite filaments constituting the roll. From this, it is clear that the adhesion between the composite filaments could be effectively removed.

In this roll treatment, the flexural stiffness of the sample taken at the time of passing through the roll of 650 mm was 100.
It was 90 kgf / cm ² . The flexural stiffness of the sample taken at the time of passing through the roll of 550 mm was 7600.
kgf / cm ² . Roll processing, groove bottom diameter 8
650mm, 440mm,
The cutting load when performed in the order of 850 mm is 1460
The weight was 0 kgf, and a decrease in strength of about 9% was observed. The bending rigidity at this time was 7000 kgf / cm ² . The reason for the decrease in strength was that a portion of the composite filamentary strip of the composite tensile strength strip was buckled and damaged due to forcible bending with a roll. Using as many rolls as possible from this,
It is preferable to gradually reduce the roll diameter, so that the adhesion between the composite filaments is gradually broken without causing damage to the composite tensile strength member, and at the same time, the flexibility is gradually reduced. It can be seen that it is possible to obtain a flexible composite tensile strength member that has been applied and finally has completely removed the adhesiveness between the composite filaments.

[0029]

According to the present invention described above, a plurality of composite filaments obtained by impregnating high-strength low-elongation fibers with a thermosetting resin are twisted and heat-treated to cure the impregnated thermosetting resin. After the composite tensile strength strip was obtained, the composite tensile strength strip was guided to an adhesive breaking device having a grooved roll, and the composite tensile strength strip was bent by the grooved roll while running the composite tensile strength strip. By repeatedly applying the torsional action, the adhesive resin layer that bonds the composite filaments to each other is sheared, so that the flexural rigidity is approximately the same as the total flexural rigidity of the composite filaments. A composite tensile strength element can be easily, efficiently and inexpensively made without any change in the process or equipment until the composite tensile strength strip is obtained. Twisted tensile strength Damage such as collapse or buckling of the body does not occur, it is possible to maintain the mechanical properties such as breaking load. Therefore, the workability when winding on the reel frame or unrolling the reel on site is good, and it can be easily inserted into a pipe buried in a curved shape inside a concrete member or underground. An excellent effect is obtained in that a composite tensile strength strip that can be tensioned in the curved state can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view showing one embodiment of a composite tensile strength strip obtained according to the present invention.

FIG. 2 is a sectional view of the same.

FIG. 3 is a sectional view of a composite tensile strength strip before application of the method of the present invention.

FIG. 4 is an explanatory view illustrating the twisting process of the composite tensile strength strip in the present invention.

FIG. 5 is an explanatory view exemplifying a heat treatment step and a bonded part breaking step in the present invention.

FIG. 6 is a plan view showing a first embodiment of a bonding part breaking step in the present invention.

FIG. 7 is an explanatory view showing a first embodiment of a bonding part breaking step in the present invention.

FIG. 8 is a partial side view of a roll in the first embodiment.

FIG. 9 is a plan view showing a second embodiment of the bonding part breaking step in the present invention.

FIG. 10 is a partial side view of a roll in the second embodiment.

FIG. 11 is a front view showing a second embodiment of the bonding part breaking step in the present invention.

[Explanation of symbols]

 A composite twist type tensile strength strip a high strength low elongation fiber b thermosetting resin b 'resin layer c coating layer 1 composite filament for core 2 composite filament for side 6 adhesive breaker

Claims (3)

(57) [Claims] 1. A plurality of composite filaments obtained by impregnating a high-strength, low-elongation fiber with a thermosetting resin are twisted and heat-treated to cure the impregnated thermosetting resin to obtain a composite tensile strength strip. Thereafter, the composite tensile strength strip is guided to an adhesive breaking device equipped with a grooved roll, and a bending and twisting action is repeatedly applied to the composite tensile strength strip by the grooved roll while the composite tensile strength strip is running. A method for producing a flexible composite twist type tensile strength strip, wherein an adhesive resin layer that bonds the strips to each other is sheared. 2. A plurality of sets of grooved rolls are arranged in series,
2. An adhesive resin layer which adheres the composite striated body to each other, is gradually broken when passing through the roll.
3. The method for producing a flexible composite twisted tensile strength strip according to 1.). 3. A grooved roll comprises a pair, each pair of rolls comprising a plurality of rolls having diameters changed stepwise, and a composite tensile strength strip is wound around these rolls and pulled. The method for producing a flexible composite twisted tensile strength strip according to claim 1, wherein the adhesive resin layers that adhere to each other are gradually peeled off.