JP2516714B2 - Method for manufacturing composite twisted strength member - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing material for concrete structures, a hanging rope for marine equipment, a mooring rope for ships, a low sag reinforcing material for cables, an operating cable for automobiles and aircraft, a suspension bridge, The present invention relates to a method for manufacturing a composite twisted type tensile strength member used as a reinforcing material for a magnetism prevention structure.

[0002]

2. Description of the Related Art A technique for obtaining a composite filament by impregnating a high-strength, low-elongation fiber with a thermosetting resin is known from JP-B-57-25679 and JP-B-62-18679. Japanese Examined Japanese Patent Sho 57-25679
The technology of No. 1 is obtained by twisting high-strength, low-elongation fibers, impregnating the twisted body with an uncured thermosetting resin after or at the same time as twisting, and further coating the outer circumference with a thermosetting resin. A composite strand is formed, and a plurality of the composite strands are twisted or braided, and then the uncured thermosetting resin is cured to form a composite filament.

The technique disclosed in Japanese Examined Patent Publication No. 62-18679 is such that a fiber core is formed by bundling, twisting, braiding and the like of high strength and low elongation fibers.
The fiber core is impregnated with a thermosetting resin, the outer periphery of the fiber core is covered with a braid, and in this state, the thermosetting resin is cured to form a composite filament.

[0004]

In the technique of Japanese Patent Publication No. 57-25679, a composite strand is prepared by impregnating a twisted body of fibers with a thermosetting resin and coating the outer periphery of the twisted body with a thermoplastic resin. Therefore, the inside of this composite strand becomes airtight, and therefore the air entrapped during resin impregnation and coating, the residual solvent in the thermosetting resin generated during heat curing, and the by-product generated during the curing reaction The gas of volatile components such as low molecular weights of the above remains inside the composite strand.
Since these gases remain as voids inside the composite strands and inside the coating, they deteriorate the mechanical properties of the composite filament.

In the technique of Japanese Examined Patent Publication No. 62-18679, since the outer periphery of the fiber core impregnated with the thermosetting resin is covered with the braided body of fibers, there is no residual gas inside, but the braided body is covered. Therefore, the thickness of the fibers increases due to the intersection of the fibers, and it is difficult to obtain a compact and high-strength composite filament.

[0006]

In order to solve such conventional problems, the present invention forms a prepreg by impregnating a multi-filament of high strength and low elongation fiber with a thermosetting resin and forming the prepreg. Pass the thermosetting resin through a drying oven to dry it and semi-harden it. A composite strand having the same, the composite strand is pulled out from a reel, and while being wound on the reel, a porous tape is wrapped around the outer periphery to cover the outer periphery, and a plurality of such coated composite strands are wound on the reel. While twisting, and after this twisting, this twisted body is passed through a heating device to completely cure the semi-cured thermosetting resin impregnated in each composite strand. That.

[0007]

A porous tape is wrapped around the outer periphery of the composite strand to cover the outer periphery of the composite strand, so that the gas inside the composite strand flows out through this coating, and therefore, deterioration of mechanical properties due to residual gas can be prevented. Also, unlike the braid, the coating is due to the winding of tape,
The thickness can be reduced, and a compact composite strength member can be obtained.

By the way, as in the present invention, the resin-impregnated prepreg is passed through a drying oven and dried to semi-cure the resin. In this state, a plurality of prepregs are wound on a reel and twisted (primary (Twisting) to form a composite strand, and then multiple such composite strands are twisted (secondary twist) while being wound on a reel while the resin is semi-cured, and this twisted body is then used in a heating device. When the resin is passed through a step of hardening the resin, the fiber-resin composite material is repeatedly bent in the process.

For example, when first setting in a twisting device, it is wound on a reel (bobbin) and a twisting spine (voice)
It is wound on a reel (capstan) when it is pulled out from the reel, and further wound on a reel (bobbin) at the time of storage after passing through the capstan, and each time it is bent. Moreover, bending also acts on the composite material when passing through the twisting die.

In the actual manufacturing process, at least 8 steps are carried out through the steps of primary twisting, tape winding and secondary twisting.
It is important that a single bend acts and the composite follows these repeated bends well.

The winding of the primary twist on the reel (first bending) is one prepreg and one simple coil winding, so that the thin prepreg itself may have some flexibility. It is sufficient that the impregnating resin is semi-cured.

However, in the first-twisting die (after the second bending), a twisted body having a predetermined number of prepregs and usually having a length of 4 to 5 mm is bent without disturbing the twisted structure. It is not enough that the prepreg is simply flexible.

To cope with this, in the present invention, the resin impregnated in the prepreg is made into a semi-cured state to suppress tackiness and the surface thereof is kept in a dry state. By such means, the friction between the prepregs contacting each other can be reduced, the smooth sliding of the prepregs can be made possible, and the twisted body can be provided with sufficient bending flexibility.

It is necessary to pay attention to the fact that the high-strength and low-elongation fiber is sensitive to the disorder of the fiber arrangement because the ultimate elongation is several%, and that buckling easily occurs when the fiber is compressed in the fiber direction. is there. Even if the resin in the resin-impregnated fiber bundle is semi-cured and the resin alone is somewhat flexible, the fiber bundle has a relatively large rigidity due to the viscosity of the impregnated resin. When this fiber bundle has a diameter of several mm, it has a considerable bending rigidity.

When bending is applied to such a fiber bundle, the initial fiber arrangement of the fiber bundle is forcibly disturbed, the bending is released thereafter, and even if the fiber bundle returns to a straight line in appearance, the fibers that are once disturbed It is difficult to return the array to the initial orderly arrayed state. Inside the bend, compressive stress causes buckling damage of the fiber.

However, as in the present invention, when a prepreg (resin-impregnated fiber bundle) which is appropriately thin and suppresses tackiness is used as a constituent unit and the twisted body constitutes a composite twisted type tensile strength body, the prepregs are Because it slides easily,
It is flexible against bending, and after the bending is released, it returns to the initial orderly twisted fiber arrangement, and its flexibility can disperse the compressive stress and prevent the occurrence of buckling, It is possible to obtain a composite twisted type tensile strength member having high strength and sufficiently exhibiting elastic properties.

Another feature of the present invention is that a prepreg is twisted to form a composite strand, the composite strand is pulled out from a reel, and while being wound on the reel, a porous tape is wrapped around the outer periphery to cover the outer periphery. , A plurality of such composite strands in a coated state are twisted together, and after this twisting, the twisted body is passed through a heating device to completely cure the semi-cured thermosetting resin impregnated in each composite strand. That is the point.

Generally, as the curing behavior of thermosetting resins,
It is known that when heating is continued, the resin once enters a fluidized state before curing begins. That is, in the initial stage of the heat treatment, the resin viscosity is lowered to about several tens poise by heating. This also appears in a prepreg in which the resin viscosity at room temperature is slightly increased by semi-curing by heat treatment at 100 ° C. for 5 minutes.

Therefore, as in the present invention, a porous tape is wound around the outer circumference of the composite strand formed by twisting the prepreg to cover the outer circumference, and a plurality of such composite strands in a coated state are twisted together. Moreover, when the semi-cured thermosetting resin impregnated in the composite strand is cured by heat treatment, when the resin viscosity decreases and becomes fluid at the initial stage of the heat treatment, it flows into the porous part of the tape. The resin rich in nature penetrates. Then, the resin gels after the middle stage of the heat treatment, and is completely cured in time, and the tape firmly adheres to the composite strand.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 2, the lead of the resin impregnating apparatus a is
7μφ carbon fiber, aramid fiber, polyamide
The total cross-sectional area of 0.46 in which 12000 fibers such as fibers are aligned in parallel
mm² This multifilament 2 is collected.
Lament 2 from reel 1 and guide roller 3
Through epoxy resin as thermosetting resin in resin tank 4
Impregnate the multifilament 2 with epoxy resin
Then, the prepreg 5 is formed.

Then, the prepreg 5 is connected to a guide roller 6
Then, the excess epoxy resin is removed so that the impregnated amount of the epoxy resin is 44 vol%, and the prepreg 5 has a circular cross section.

After that, the prepreg 5 is passed through a drying furnace 8 and dried at a temperature of 100 ° C. for 5 minutes to semi-cure the epoxy resin. Then, the prepreg 5 is sequentially wound on the reel 10.

Since the epoxy resin of the prepreg 5 is semi-cured and its surface is in a dry state, even if the prepreg 5 is continuously wound by the reel 10, the peripheral surfaces thereof do not adhere to each other.

Next, as shown in FIG. 3, the reel 10 in which the prepreg 5 is wound around the stand 12 of the twisting device b is
Five prepregs 5 in which the epoxy resin remains semi-cured are pulled out from each reel 10 and a pair of joining rollers 13 are attached.
It passes through the gap and is further introduced to the reel 14.

15 reels of prepreg 5 with reel 14
While collectively winding, the reel 14 is rotated in the direction of the arrow and twisted at a twist pitch of 90 mm (corresponding to 22.5 times the finished diameter of 4.0 mm) to form a composite strand 15 of 4.0 mmφ.

After this, as shown in FIG. 4, the reel 14 in which the composite strand 15 is wound around the support shaft 18 of the coating device c.
, The composite strand 15 is pulled out from the reel 14 through the guide roller 19, and the end thereof is reeled into the reel 2.
Attach to 0.

The coating device c is equipped with a winding machine 21, and a porous tape 22 such as a woven tape or a non-woven tape is wound on the winding machine 21. The porous tape 22 is made of, for example, polyester, polyamide, or aramid fiber and has a width of 20 mm and a thickness of 0.1 mm.

Then, the composite strand 15 is attached to the reel 2
The winding machine 21 is wound around 0, and the winding machine 21 is swung around the outer periphery of the composite strand 15 in the middle, and this operation sequentially winds the tape 22 around the outer periphery of the composite strand 15 to cover the outer periphery of the composite strand 15. At this time, for example, the winding angle of the tape 22 is 37 °, the pitch is 17 mm, and the tape 22 is wound so that half of the width of the tape 22 overlaps each other.

After this, seven reels 20 on which the composite strand 15 has been wound are mounted on the twisting device d as shown in FIG. 5, and the twist angle (tan θ is set in the opposite direction to the twist direction of the composite strand 15). ) As shown in Fig. 1 after twisting at 5.8,
A twisted body 25 having a (1 × 7) twist structure is formed, and the twisted body 25 is wound on a reel 27 and passed through a heating device e and heated at 130 ° C. for 90 minutes as shown in FIG. ,
The semi-cured epoxy resin impregnated in each composite strand 15 is completely cured to obtain a composite twist type strength member.

As described above, since the porous tape 22 is wrapped around the outer periphery of the composite strand 15 to cover the outer periphery thereof, the gas inside the composite strand 15 flows out through this coating, and therefore the mechanical force caused by the residual gas is generated. The deterioration of properties can be prevented, and the coating is different from the braided body because the tape is wound. Therefore, it is possible to obtain a compact composite twist type tensile strength body which can be made thin.

The prevention of residual gas is effective in improving various mechanical properties, and particularly in improving strength utilization efficiency and tensile fatigue properties. Further, the reduction of the coating thickness greatly contributes not only to the improvement of the cutting load but also to the improvement of relaxation characteristics.

By the way, the total cross-sectional area of the fibers when forming the prepreg 5 is 2.0 mm ² It is desirable to set it to below the level. If this cross-sectional area is too large, it becomes difficult for the resin to penetrate inside. The impregnation rate of the thermosetting resin is preferably set in the range of 25 to 60 vol%. In general, it is desirable that the amount of the thermosetting resin is small, because it is more compact. However, if it is set to 25% or less, it becomes difficult to allow the thermosetting resin to penetrate into the fibers.

The twist strength of the composite strand 15 cannot be defined by the twist angle. This is because this value is different between the inside and the surface. Therefore, the present inventor grasped the degree of the twist strength by the ratio of the twist length to the diameter. Then, as shown in FIG. 7, when the ratio is less than 8, the strength utilization efficiency sharply decreases. Therefore, the limit of this ratio is 8 or more.

When the relationship between the strength utilization efficiency of the twisted body 25 and the twist angle was measured, tan θ was 3 as shown in FIG.
It has been found that the strength utilization efficiency drops sharply when the value falls below the range. Therefore, the range of tan θ is 3 or more.

The composite twist type tensile strength body of the present invention is used as a core, and a plurality of composite strands in which the thermosetting resin remains semi-cured are twisted around the outer periphery of the core and heated to obtain the thermosetting resin. Can be completely cured to form an outer layer body, and a plurality of similar outer layer bodies are sequentially provided on the outer periphery of the outer layer body to form a thick composite twisted type tensile strength body.

[0037]

As described above, according to the present invention, the gas inside the composite strand flows out through the coating, and therefore, the deterioration of mechanical properties due to the residual gas can be prevented, and the coating is not a braid. Differently, since it is due to the winding of a porous tape, the thickness can be reduced, and a compact composite twisted type tensile strength member can be obtained. Then, the prepreg impregnated with the resin is passed through a drying oven, dried to semi-cure the resin, and in this state, a plurality of prepregs are wound on a reel and twisted to form a composite strand. As the resin is semi-cured, it is twisted while winding it with a reel, and after this twisted body is passed through a heating device to cure the resin, it is well suited for bending repeatedly applied during the process. Following this, a high-strength composite twisted type tensile strength member can be manufactured.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a composite twist type strength member according to an embodiment of the present invention.

FIG. 2 is a diagram showing a resin impregnation step of impregnating a multifilament with a thermosetting resin.

FIG. 3 is a diagram showing a twisting step of twisting a prepreg.

FIG. 4 is a diagram showing a coating step of winding a tape around the outer periphery of the composite strand to cover the same.

FIG. 5 is a diagram showing a twisting step of twisting the composite strands.

FIG. 6 is a diagram showing a heating step of heating a twisted composite strand.

FIG. 7 is a diagram showing the relationship between the ratio of pitch and diameter of the composite strand and strength utilization efficiency.

FIG. 8 is a diagram showing a relationship between a twist angle of a twisted body and strength utilization efficiency.

[Explanation of symbols]

 2 ... Multifilament 5 ... Prepreg 8 ... Drying oven 15 ... Composite strand 22 ... Tape

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area E04C 5/07 B29K 105: 10 // B29K 105: 10 B29L 31:10 B29L 31:10 7310-4F B29C 67/14 X

Claims (3)

(57) [Claims] 1. A prepreg is formed by impregnating a multifilament of high strength and low elongation fiber with a thermosetting resin, and the prepreg is passed through a drying oven to dry the thermosetting resin to semi-cure it. A plurality of prepregs in such a state are wound on the reel while the thermosetting resin is semi-cured and twisted to form a flexible composite strand, which is pulled out from the reel and wound on the reel. A porous tape is wound around the outer periphery to cover the outer periphery, and a plurality of such coated composite strands are twisted while being wound on a reel, and after this twisting, the twisted body is passed through a heating device. A method for producing a composite twisted type tensile strength member, which comprises completely curing a semi-cured thermosetting resin impregnated in each composite strand. 2. The method for producing a composite twisted type tensile strength member according to claim 1, wherein a plurality of prepregs are twisted at a pitch of 8 times or more of a twisted finished diameter. 3. The method for producing a composite twist type tensile strength member according to claim 1, wherein a plurality of composite strands are twisted at a twist angle of tan θ of 3 or more.