JP5431827B2 - Manufacturing method of substantially rectangular thermoplastic resin-coated FRP filament, and drop optical fiber cable using the FRP filament - Google Patents

Description

  The present invention relates to a method for producing a substantially rectangular thermoplastic resin-coated FRP filament used as a tension member for a non-metallic drop optical cable, and a drop optical fiber cable using the FRP filament.

With the arrival of the information society and the increase in transmission information capacity such as the Internet, so-called FTTH, in which optical fiber cables are laid to subscribers such as buildings and houses, is rapidly progressing.
As a drop optical fiber cable for FTTH, one using a metal wire as a tension member (hereinafter sometimes referred to as TM) has been proposed. However, grounding is necessary to avoid surging due to lightning. The labor and construction cost increased, and there was a problem in the spread to each home.
Therefore, a non-metallic drop optical fiber cable that eliminates the need for grounding work by using non-metallic TM such as FRP (fiber reinforced synthetic resin) wire instead of metal wire TM has been studied. Drop optical fiber cables of the type are mainstream.

In conventional non-metallic drop optical fiber cables, FRP tension members generally have a round cross section (for example, Patent Document 1).
However, if the tension member is FRP, there is a disadvantage that it is easy to break with a large bending diameter as compared with a metal wire. Therefore, as a method of overcoming this, the present applicant has not yet used a thermosetting resin. A method for producing FRP with a thermoplastic resin coating, in which two outer coating layers are formed on the outer periphery of the cured FRP, the FRP portion is then heat-cured, and then only the outer coating portion is peeled and removed. (Patent Document 2). According to the method for manufacturing an FRP for a drop optical cable described in Patent Document 2, by making the cross-sectional shape of the FRP rectangular, the short side of the FRP is about 0.3 mm, and a plurality of reinforcing fiber bundles such as glass fiber yarns. Can be used to provide a tension member having a small minimum bending diameter and excellent anti-shrinkage force, but has a short side of less than 0.3 mm and uses a small number of reinforcing fiber bundles, particularly one organic synthetic fiber bundle. In this case, it has been found difficult to obtain a rectangular FRP having a uniform flatness.

  More specifically, because of the high tensile strength compared to glass fibers and the difficulty of bending when bent to a small diameter, when using filamentous organic synthetic fibers as reinforcing fiber bundles, reinforcing fiber bundles with low fineness are used. When a plurality of fibers are used, a bundle of reinforcing fibers that are inherently low in fineness is expensive due to an increase in manufacturing cost, resulting in an increase in the cost of FRP. In the production of FRP, the smaller the number of reinforcing fiber bundles, the fewer the man-hours for handling and the better the workability. Furthermore, depending on the type of organic synthetic fiber, there is a case in which only a multifilament of about 1000 to 4000 dtex and no fineness is present, so that a multifilament having a high fineness must be used. In addition, when multiple bundles of low-fidelity reinforcing fibers are used, there are problems such as an increase in the number of man-hours for attaching to the creel due to an increase in the number of handling, and difficulty in uniformly dispersing the reinforcing fibers in the FRP. In particular, in the production of a rectangular FRP having a small short side, there are problems such as poor dispersion of reinforcing fibers used and occurrence of twisting.

Japanese Patent Laid-Open No. 2004-163501 JP 2005-157159 A

  As described above, conventionally, there has been no proposal for an improved method for producing a thermoplastic resin-coated FRP filament having a substantially rectangular shape in which the short side of the FRP portion is less than 0.3 mm. The present inventors have earnestly developed a method for continuously producing an FRP tension member having a good cross-sectional shape in response to a request for further weight reduction as an optical fiber cable tension member and a reduction in minimum bending diameter. As a result of the study, (i) suppressing twisting of the reinforcing fiber bundle in the manufacturing process, (ii) eliminating the unevenness of the fiber in the FRP cross section, and keeping the shape and dimensions constant, (iii) the thermoplastic resin coating layer The present invention was completed with the object of knowing that it is necessary to uniformly control the coating thickness over the entire circumference and developing these specific techniques.

In order to solve the above-mentioned problems, the present inventors control the tension applied to the reinforcing fiber bundle to open the reinforcing fiber and guide it to the thermosetting resin impregnation tank. After drawing into a rectangular shape, the present inventors have found that the above-mentioned problem can be solved by coating the inner peripheral side of the coated cone portion discharged from the annular die as a reduced pressure in the thermoplastic resin coating step.
That is, the present invention
[1] Impregnation step (1) of impregnating a reinforcing fiber bundle made of organic synthetic fibers with an uncured thermosetting resin composition, the reinforcing fiber bundle impregnated with the thermosetting resin composition has a rectangular hole shape A drawing process (2) for shaping into a predetermined rectangular shape using a drawing nozzle, and a melted thermoplastic resin from an annular die is cone-shaped on the outer peripheral surface of the drawn rectangular uncured filament. A coating step (3) for forming a coating layer by discharging to the surface, a sizing step (4) for forming a flat shape by pressing with parallel rolls with a predetermined gap, and cooling for solidifying the coating layer by introducing it into a cooling water bath A method for producing an FRP filamentous article comprising a solidification step (5) and a heat curing step (6) for curing the thermosetting resin,
In the impregnation step (1), the reinforcing fiber bundle made of organic synthetic fiber is pulled out from the bobbin around which the reinforcing fiber bundle is wound, and the tension is reduced to 40 cN or more and 280 cN or less per reinforcing fiber bundle. The reinforcing fiber bundle is opened in a substantially untwisted state and introduced into an impregnation tank containing a thermosetting resin, the resin content of the FRP filament is 45% by weight or less, and the coating Step (3) is an inner side of a cone-shaped thermoplastic resin in which a polyolefin-based thermoplastic resin having an MI of 2 g / 10 min or more is discharged from an annular die before contacting the outer periphery of the rectangular uncured filament. A method of producing a substantially rectangular thermoplastic resin-coated FRP filament,
[2] In the impregnation step (1), the means for opening the reinforcing fiber bundle in a substantially non-twisted state is a reinforcement before introducing the impregnation tank in which the thermosetting resin is accommodated from the winding bobbin for feeding the reinforcing fiber bundle. In the above [1], a tension adjustment guide is provided between the fiber bundle guides, and all guides including the tension adjustment guide are non-rotating guide bars having a diameter of 20 mm or less, and the surface roughness Ra is 1 μm or less. The method for producing the substantially rectangular thermoplastic resin-coated FRP filament described in the above,
[3] The method for producing a substantially rectangular thermoplastic resin-coated FRP filament according to [2], wherein the guide bar is mirror-finished hard chrome plated,
[4] The method for producing a substantially rectangular thermoplastic resin-coated FRP filament according to any one of [1] to [3], wherein the thermosetting resin is a vinyl ester resin,
[5] The substantially rectangular shape according to any one of [1] to [4], wherein the organic synthetic fiber has a tensile elastic modulus of 360 cN / dtex or more and an elongation at break of 3.5% or more. Production method of thermoplastic resin-coated FRP filaments,
[6] The method for producing a substantially rectangular thermoplastic resin-coated FRP filament according to any one of [1] to [5], wherein the organic synthetic fiber is an aromatic polyamide fiber,
[7] A substantially rectangular thermoplastic resin-coated FRP filament obtained by the production method according to any one of [1] to [6], and [8] In the above [7] The drop optical fiber cable is characterized in that the substantially rectangular thermoplastic resin-coated FRP filament described is used as a tension member.

According to the production method of the present invention, the thermoplastic resin-coated FRP filament having the substantially rectangular FRP in which the upper and lower sides on the long side of the substantially rectangular cross section are parallel to each other and the reinforcing fibers are uniformly dispersed. Products can be obtained with high productivity and high yield.
The thermoplastic resin-coated FRP filament having a substantially rectangular FRP according to the present invention has a substantially rectangular shape as a coated filament and has a uniform property in the longitudinal direction. When using as a tension member for a drop optical fiber cable, as a tension member for a drop optical fiber cable, as a product cable in a cross section perpendicular to the longitudinal direction of the cable, it is necessary to fully demonstrate the performance of the tension member. A drop optical fiber cable that can be easily introduced at a desired position and angle of the cable cross section and has no production trouble or quality problem and stable in productivity and quality can be provided.

(A) Explanatory drawing which shows an example of the first half of the manufacturing process of the substantially rectangular thermoplastic resin coating | cover FRP filament of this invention, (B) It is explanatory drawing which shows the second half. It is explanatory drawing of the measuring method of the twist (twist) number of a reinforcing fiber bundle. It is a graph which shows the relationship between tension and the number of twists. It is explanatory drawing of the tension | tensile_strength provision to a reinforcing fiber bundle, and the fiber opening condition. It is explanatory drawing of the die | dye part which coat | covers an uncured FRP with a thermoplastic resin. It is situation explanatory drawing immediately after a thermoplastic resin coating. 2 is a cross-sectional enlarged photograph of a substantially rectangular thermoplastic resin-coated FRP filament obtained in Example 1. FIG. 12 is a cross-sectional enlarged photograph of a substantially rectangular thermoplastic resin-coated FRP filament according to Comparative Example 6. It is sectional drawing which shows typically an example of the drop optical fiber cable using the substantially rectangular-shaped thermoplastic resin coating | cover FRP filament according to this invention.

The method for producing the substantially rectangular thermoplastic resin-coated FRP filament of the present invention is as described in claim 1. An embodiment of a method for producing a substantially rectangular thermoplastic resin-coated FRP filament of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic view showing a production process of a substantially rectangular thermoplastic resin-coated FRP filament according to the present invention. (A) shows, as a preceding stage, thermoplastic resin coating and flat shaping, cooling of uncured FRP. (B) shows the subsequent stage until heat curing and winding. In the drawing, the process is divided into the first and second stages because of the paper width, and both processes are continuous without interruption. ing.
1A and 1B show that the process moves from the right side to the left side of the figure.
The method for producing a substantially rectangular thermoplastic resin-coated FRP filament according to the present invention is particularly prior to the impregnation step (1) in which a reinforcing fiber bundle made of organic synthetic fibers is impregnated with an uncured thermosetting resin composition. At the stage, the reinforcing fiber bundle made of organic synthetic fiber is pulled out from the bobbin around which the reinforcing fiber bundle is wound, and the plurality of non-rotating rotations are performed under a tension of 40 cN or more and 280 cN or less per reinforcing fiber bundle. Twist as a fiber bundle that is brought into contact with a rod (hereinafter sometimes referred to as “opening bar” or “tension bar” or simply “bar”) and caused by distortion of the fibers that are inherent, twisting, entanglement, etc. Without exhibiting twist, opening the reinforcing fiber bundle into a substantially untwisted state and introducing it into an impregnation tank containing a thermosetting resin, on the outer peripheral surface of a drawn rectangular uncured filament, Is it an annular die? In the coating step (3) for discharging and coating the molten thermoplastic resin in a cone shape, the inner side of the cone-shaped thermoplastic resin is coated in a reduced pressure state before contacting the outer periphery of the rectangular uncured filament. It is characterized by that. The spread bar is usually preferably a metal bar from the viewpoint of strength and durability, and may be made of a material such as ceramics. On the other hand, when the tension exceeds 280 cN, the tension is too large, and the internal strain is changed to entanglement, resulting in a twist. On the other hand, if the tension falls below 40 cN, the inherent strain is not removed and is brought into the draw forming process as it is, and it is not good because it is manifested as twist.

  First, the present inventors conducted the following experiment on the opening of the reinforcing fiber, and it is desirable that the reinforcing fiber bundle has no twist (twist), but the number of twists is 0.5 times / m or less. I learned that it could be opened.

In order to prevent twisting in the manufacturing process of the thermoplastic resin-coated FRP filamentous material with respect to the reinforcing fiber constituting the FRP, the winding shaft (bobbin) around which the reinforcing fiber is wound is rotated. The so-called longitudinal take-up without taking out in the direction of the winding axis is not appropriate because the fiber is twisted once each time it is drawn out (one round), and is not suitable while rotating the take-up bobbin or while taking up the take-up bobbin. So-called lateral feeding (storing), which is taken out in the rotation direction, is an essential condition.
However, twisting cannot be avoided simply by performing normal lateral feeding.
This is because a general continuous fiber filament is always entangled between a large number of single fibers constituting a water cooling process after spinning or a heat drawing process in the production stage (difference in length between single fibers). This is because, when the tension is applied at the time of feeding, the entangled part returns and the whole fiber twists, that is, twists develop. . This is an inherent problem that arises because the reinforcing fibers are continuous multifilament yarns.
Therefore, first, the relationship between the fiber feeding tension and the twist amount was investigated by the following method.

(Relationship between tension and twist during fiber unwinding)
As shown in FIG. 2, a fiber F is fed straight 20 m from a bobbin B wound with a multifilament of aromatic aramid fibers (manufactured by Toray DuPont: Kevlar 29, 1670 dtex / 1000f). While holding the tip with the tension applied, the top and bottom of the fiber F are firmly sandwiched between the two non-rotating bars R, the bar is sequentially translated to the tip side, and the twist existing between them is moved to the tip side. The twist was collected on the most advanced side. While maintaining the holding of the fiber by the two bars and fixing it horizontally, the twist accumulated in the holding portion H at the tip is rotated in the returning direction, and the number of rotations n until the twist disappears is measured. The number of twists per meter (T / m) was determined by dividing the rotational speed n by 20 m.
The tension applied to the fiber bundle adopts a method in which a weight is suspended from a hook portion provided at the end of the fiber bundle via a pulley-like thread guide (not shown) provided to the left of the tip H in FIG. The load was changed by changing the weight of the weight in various ways.

  FIG. 3 is a graph showing the relationship with the twist (number of rotations / 20 m) when the tension applied to the fiber is changed. The tension is linear up to 500 cN, and the twist enters when the tension is high. It was confirmed that it was easy.

Further, it has been found that it is effective to open the reinforcing fibers in order to prevent twisting of the reinforcing fibers. As a result of examining the opening of the fiber to prevent twisting, it was found that the fiber can be opened by a simple method of pressing the fiber against the bar. However, in this opening method, it is confirmed that the fiber cannot be fully opened unless the twist of the fiber when entering the bar is reduced to 0.5 rotation / m or less, and the twist or twist of the fiber bundle is 0.5 times / twist. From the graph of FIG. 3, it was found that the tension should be 280 cN or less in order to make it m or less.
In the production method of the present invention, “substantially unopened state” means that the reinforcing fiber bundle has no twist or twist at all, or 0.5 times or less per 1 m. Say.

As shown in FIG. 4, the tension adjustment in the unwinding process is performed by passing the reinforcing fiber bundle F unrolled from the take-up bobbin in the bobbin rotation direction via the first tension bar TB1, and then swinging up and down for tension adjustment. A possible tension adjustment guide bar (hereinafter referred to as “dancer”) DB is brought into contact with the lower half side of the DB, and then the reinforcing fiber bundle is caused to travel at a predetermined speed of 40 m / min via the slit-shaped guide G, thereby the slit-shaped guide. Experiments were conducted to confirm the relationship between the fiber opening property of G and the fiber opening property by changing the presence or absence of rotation of the dancer (oscillator) DB, the outer diameter, and the like. Table 1 summarizes the relationship between the shape of the dancer DB and the spreadability when the tension is 90 cN. In addition, the evaluation shows that the reinforcing fiber bundle is not twisted if at least the fiber width is opened to 10 mm or more. "
In addition, the fiber spreading width in the slit-shaped guide G was measured with a vernier caliper.
Assuming that the value obtained by dividing the spreading width of the reinforcing fiber bundle by the number of filaments is the yarn width ratio, it was confirmed that the yarn width ratio is preferably 8 to 12 μm / filament, and particularly preferably 9 to 11 μm / filament.

As shown in Table 1, when the dancer shape is (i) a rotating object such as a roller, the fiber bundle is twisted regardless of the outer diameter, and the openability evaluation is poor. (ii) Even if the dancer shape is a fixed bar, if the diameter is large (φ40 mm), the fiber bundle is twisted, and the openability evaluation is poor. The fixed bar is a bar-like tension bar whose surface does not rotate. (iii) If the first tension bar TB1 is also rotated, the fiber bundle is twisted. (iv) Even if the first tension bar TB1 is a fixed bar, if the diameter is large, the fiber bundle is twisted. (v) When a fixing bar having a diameter of 15 mm or less was used, the fiber opened to open to 10 mm or more, and twisting of the fiber bundle was not observed.
From the above experimental results, in the manufacturing method of the substantially rectangular thermoplastic resin-coated FRP filament of the present invention, as an arrangement of guides as shown in FIG. It is possible to eliminate twisting by removing the part where the fibers are gathered, such as U-shaped curved concave parts, and opening the fiber as soon as it is unwound and taking it to the impregnation and drawing process. I knew it.

  In addition, a fixed bar with a diameter of 15 mm, a mirror-finished product with a hard chrome plating surface, and a surface-treated surface with sandpaper were prepared and tested. The fluff and fiber-derived sizing agent adhered and deposited on the surface. Therefore, the surface of the fixing bar is preferably a surface having a surface roughness Ra of 1 μm or less from the viewpoint of preventing the adhesion of the sizing agent.

Next, the coating process which is the second feature of the method for producing the thermoplastic resin-coated FRP filament of the present invention will be described in detail. As shown in FIG. 1 (A), the reinforcing fiber bundle F introduced into the impregnation tank 5 in which the thermosetting resin composition is accommodated in the opened state passes through a guide in the impregnation tank, and is uncured linear. As a product 1a, a crosshead portion of a melt extruder 7 for coating a thermoplastic resin passes through a squeezing nozzle group 6 having a rectangular hole shape arranged so that a rectangular cross section gradually converges to a final rectangular shape. 8 is formed into a rectangular shape by a final throttle nozzle 60 shown in FIG. 5 having a predetermined throttle shape, and a thermoplastic resin coating is applied by passing the crosshead part 8.
FIG. 5 is a plan sectional view of the uncured linear object 1a as viewed from above in a state where the uncured linear object 1a is guided to the final throttle nozzle mounted on the cross head 8 through the throttle nozzle groups 6a to 6d. Since the final squeezing nozzle 60 is heated by the heat from the cross head, it has a double jacket for circulating cooling with water in order to prevent the resin of the uncured linear material from being cured. And a drain pipe 62.

On the other hand, as shown in FIG. 5, the thermoplastic resin coating is obtained by extruding a molten resin from an annular die 91 through a conduit portion 90 in a crosshead 8 attached to the tip of a melt extruder 7, and uncured wire. This is done by coating the outer periphery of the material seamlessly.
In this coating, as shown in FIG. 6, the coating resin discharged from the annular die 91 has a cone-shaped heat before coming into contact with the outer periphery of the uncured linear object 1a continuously supplied through the final squeezing nozzle. The inner side 94 of the plastic resin 95 needs to be decompressed by a decompression line connected to the pipe 93. The degree of vacuum is changed by adjusting the contact point T between the uncured linear object and the coating resin to a predetermined distance (10 ± 4 mm) from the exit surface of the die 91 by the pressure reduction operation. And the air accompanying the uncured filament 1a, the volatile gas in the thermosetting resin composition, etc. are sucked to generate foaming of the covering portion and the thermosetting resin composition. The degree of decompression must be sufficient to prevent process troubles such as coating breakage due to foreign matter accumulated as a source, product defects, and the like.
The degree of vacuum is preferably −1 to −15 kPa. After the outer periphery of the uncured linear material and the thermoplastic resin coating are in contact with each other and coated, they are sandwiched by a pair of upper and lower parallel rolls 9 and shaped into a flat shape (sizing), and the uncured thermoplastic resin-coated FRP wire It is sent out to the cooling water tank 10 as the strip 1b.

Next, as shown in FIG. 1B, the uncured thermoplastic resin-coated FRP filament 1b is inserted into a pressurized steam heat curing tank 11 sealed at both ends to cure the internal thermosetting resin. After that, the substantially rectangular thermoplastic resin-coated FRP filamentary element wire 1 cooled in the cooling water tank (FIGS. 1B and 12) is taken up by the winder 14 and wound on the bobbin. In FIG. 1B, the Nelson roller 13 is used as the wire take-up device, but the take-up device is not limited to the Nelson type but may be a belt type or a caterpillar type device.
1 shows a method of manufacturing one substantially rectangular thermoplastic resin-coated FRP filament, but it has a structure in which a plurality of final aperture nozzles can be mounted on the crosshead die part. In addition, a plurality of uncured filaments that have been drawn and formed into a coated die structure that can be individually coated with a thermoplastic resin can enable simultaneous production of a plurality of pieces. , Productivity can be improved.

Hereinafter, the raw material which can be used for the manufacturing method of the substantially rectangular-shaped thermoplastic resin coating | cover FRP filament of this invention is demonstrated.
Organic synthetic fibers as reinforcing fibers that can be used in the method for producing a substantially rectangular thermoplastic resin-coated FRP filament of the present invention include aromatic polyamide fibers (aramid fibers), polyarylate fibers, polyparaphenylene benzobisoxazole ( PBO) fiber, polyparaphenylene benzobisthiazole (PBT) fiber, and the like.
These organic synthetic fibers preferably have a tensile elastic modulus of 360 cN / dtex or more and an elongation at break of 3.5% or more.
If the tensile modulus is 360 cN / dtex or more, it has a high tensile strength to protect the optical fiber core as a tension member of the optical fiber cable, and the elongation at break is 3.5% or more. Therefore, it is difficult for the FRP to be bent, and it is possible to have sufficient buckling resistance without hindering the handling and wiring work after the drop optical fiber cable.
An even more preferable tensile elastic modulus is 480 cN / dtex or more.

  As the organic synthetic fiber to be used, a so-called multifilament-shaped fiber having a single fiber diameter of 10 to 15 μm and not twisting a plurality of yarns is desirable, and 500 to 2000 dtex is used. In this case, when a reinforcing fiber having a large count, that is, a reinforcing fiber exceeding 2000 dtex is used, it has an adverse effect on the rectangularity when FRP is used, and a uniform coating can be performed in a subsequent thin-wall coating molding process using a thermoplastic resin. It becomes difficult. In addition, the single yarn is poorly aligned, and there is a possibility that the tensile performance becomes insufficient when it is made into FRP. On the other hand, yarns of 500 dtex or less are also commercially available, but the process becomes complicated and the cost increases, which is not economical. In addition, the organic synthetic fiber is preferably an aromatic polyamide fiber because it has been used for the purpose of reducing the diameter and weight. Aromatic polyamide fibers can be broadly classified into meta and para types, regardless of their type. For example, polyparaphenylene terephthalamide fibers (trade name “Kevlar”), Teijin sold by Toray DuPont Co., Ltd. Examples thereof include aramid fibers such as “Technola” and “Twaron” para-aramid fibers sold by the corporation.

  The volume content of the reinforcing fiber of the FRP filamentous material is determined by the required physical properties, but in the present invention for the purpose of further reducing the diameter, it is generally 55 to 70 Vol. %, That is, the resin content complementary to the volume content of the reinforcing fiber is 45 Vol. % Or less, 30% Vol. The above is preferable because the occurrence of a squeezing phenomenon during sizing by a pinching roll immediately after coating with a thermoplastic resin hardly occurs, and a decrease in mechanical properties of the FRP obtained after curing can be suppressed.

  Further, in the thermoplastic resin-coated FRP filament of the present invention, the thermosetting resin that can be used for binding organic synthetic fibers as reinforcing fibers is terephthalic acid-based or isophthalic acid-based unsaturated polyester resin, vinyl ester resin. (Epoxy acrylate resins, etc.) or epoxy resins are common, and these are used after adding a curing catalyst, etc. Especially, vinyl ester resins (epoxy acrylate resins, etc.) are from the viewpoint of physical properties such as heat resistance. preferable.

Calcium carbonate can be added to the thermosetting resin composition. The average particle diameter of calcium carbonate is preferably 3 μm or less from the viewpoint of sedimentation in a resin impregnation tank, prevention of thermoplastic resin coating breakage, uniform dispersibility in the FRP portion, and the like.
The addition amount of calcium carbonate is 0.5 to 3 parts by mass with respect to 100 parts by mass of the thermosetting resin. If the addition amount is in the range of 0.5 to 3 parts by mass, the dimensional variation rate of the thermoplastic resin-coated FRP filament is low, it has good minimum bending characteristics, and can be used as a tension member of a drop optical fiber cable. Is possible.

  The thermoplastic resin used for the coating layer of the uncured FRP filament 1a is selected from resins compatible with the thermoplastic resin of the main body coating portion 47 shown in FIG. Moreover, in the manufacturing process of the thermoplastic resin-coated FRP filament, it is preferable to use a transparent thermoplastic resin from the viewpoint that the state of the outer periphery of the FRP portion, the uneven thickness of the coated thermoplastic resin layer, etc. can be easily confirmed.

Further, the thermoplastic resin used for the coating layer preferably has an inner periphery in a molten or softened state when the thermosetting resin is heated and cured in order to obtain an anchor adhesion structure with the FRP portion, and a curing temperature of 110 to 150. A polyolefin resin having a melting point or softening point in the range of ° C. is more preferred.
The degree of anchor adhesion is preferably such that the pulling force of the FRP part from the thermoplastic resin used for the coating layer is 10 N / 10 mm or more.

  In order to set the thickness of the coating layer to about 0.02 to 0.1 mm, a resin with good thin film moldability is desirable. For example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), etc. Is preferred.

When LLDPE is used, it is more preferable to use one having the following characteristics. The properties are as follows: melt index MI according to JIS K6760 is 2 g / 10 min or more, density is 0.920 to 0.940 g / cm ³ , tensile strength is 30 MPa or more in a tensile test according to JIS Z1702, and 1% modulus is 150. Those having a value in the range of ~ 250 MPa are preferred.
Moreover, you may mix and use 2 types of resin of different MFR which has MI in the range of 2 g / 10min or more. Note that the upper limit of MI is approximately 4 g / 10 min.

  The obtained thermoplastic resin-coated FRP filament can then be further shaped into a rectangular shape by passing through a molding heating mold block or the like as necessary.

The present invention also provides a thermoplastic resin-coated FRP filament obtained by the production method and a drop optical fiber cable using the thermoplastic resin-coated FRP filament.
FIG. 9 is a schematic cross-sectional view showing an example of the optical fiber cable of the present invention. The drop optical fiber cable 1 shown in the figure includes an optical fiber core 42, a tension member 43 made of a thermoplastic resin-coated FRP filament, and a messenger wire 44.

  The tension member 43 is formed in a flat, substantially rectangular cross section in which a core portion 45 made of FRP is covered with a thermoplastic resin coating layer 46, and the pair of tension members 43 are arranged in the vertical direction of the optical fiber core wire 42. It arrange | positions coaxially so that this may be pinched | interposed at predetermined intervals.

  The messenger wire 44 is disposed on one tension member 43, and the optical fiber core wire 42 and the tension member 43 have a configuration in which they are collectively covered with a main body covering portion 47 made of thermoplastic resin. A pair of notches 48 are formed on the body covering portion 47 so as to face each other on both sides of the optical fiber core wire 42. Further, the messenger wire 44 is connected by a narrow width portion 49 so as to be separable from other portions.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely according to an Example, this invention is not restrict | limited to the following Example.

Example 1
In the step shown in FIG. 1 (A), a para-aromatic aramid fiber multifilament (manufactured by Toray DuPont: Kevlar 29 1670 dtex / 1000f, elongation at break 3.6%, tensile modulus 490 cN / dtex) is used as the reinforcing fiber. From the wound bobbin B, the tension of the dancer 3 is extended to 200 cN, 100 parts by weight of vinyl ester resin (Showa High Polymer, R-3130), and the trade name “Cadox” manufactured by Kayaku Akzo as a thermosetting catalyst. After being led to an impregnation tank 5 containing an uncured thermosetting resin to which 4 parts by mass of BCH50 ”and 1 part by mass of“ Kayabutyl B ”are added, the reinforcing fiber bundle F is impregnated with the thermosetting resin. , After passing through the diaphragm nozzle group 6 whose shape has been reduced in stages, the final diaphragm nozzle passes through a rectangular diaphragm nozzle of 1.18 × 0.15 mm, The fat content was 30 volume%. Linear low-density polyethylene (LLDPE, NUCG5361, MI = 4 manufactured by Nihon Unicar Co., Ltd.) was melt-extruded from an annular die at an extrusion temperature of 170 ° C., coated at a reduced pressure of −10 kPa to a coating thickness of about 0.1 mm, and a gap of 1 After pressing with the parallel sizing roller 10 of 40 mm, the thermoplastic resin coating layer was subsequently cooled to the cooling tank 11.

  Thereafter, it was guided to a steam pressure heat curing tank 12 of 0.4 MPa (approximately 145 ° C.) at a speed of 40 m / min and cured. Subsequently, it was cooled by passing through a cooling water tank 13. A linear product 1 having a coating shape after curing and cooling of 1.40 × 0.34 mm and an outer shape of FRP of 1.26 × 0.14 mm was obtained. As can be seen from the enlarged photograph of the cross section shown in the figure, the upper and lower long sides of the cross section are parallel to each other, and are coated with a uniform thickness, reflecting the fact that they are coated with an annular die, and the short side has an R shape. Was presenting.

Example 2
In Example 1, a thermoplastic resin-coated FRP filament was obtained in the same manner as in Example 1 except that the reinforcing fiber bundle opened with the tension of the reinforcing fiber bundle F set to 100 cN was introduced into the impregnation tank. The shape and physical properties of the obtained thermoplastic resin-coated FRP filament were the same as in Example 1.

Comparative Examples 1 and 2
In Example 1, the reinforcing fiber bundle F was set to 300 cN (Comparative Example 1) and 400 cN (Comparative Example 2), and the opened reinforcing fiber bundle was introduced into the impregnation tank. A resin-coated FRP filament was obtained. In both Comparative Examples 1 and 2, twisting of the reinforcing fiber bundle was observed in the manufacturing process, and the product was observed to be entangled with the reinforcing fiber in the longitudinal direction of the coated wire. The cross-sectional shape of the FRP is not a substantially rectangular shape in which the upper surface and the lower surface are parallel, and there has been a concern about problems in the manufacturing process of the optical fiber cable.

Examples 3 and 4 and Comparative Examples 3 and 4
In Example 1, the degree of vacuum during the thermoplastic resin coating was -15 kPa (Example 3), the degree of vacuum was 0 kPa (Comparative Example 3), and the MI of the coating resin in Example 1 was 2.4 g / 10 min (Nihon Unicar). LDPE, NUC8321) (Example 4), 1.2 g / 10 min (Nidec Unicar LLDPE, NUCG7651) (Comparative Example 4), and the same thermoplastic resin-coated FRP filaments as in Example 1. Got. The thermoplastic resin-coated FRP filaments according to Examples 3 and 4 had the same good shape as in Example 1, but in Comparative Example 3 with a degree of vacuum of 0 kPa, the uncured filaments were accompanied. In this case, since the coating is performed in a state where air is brought in, foaming occurs at the time of curing and the coating is broken, so that continuous production is impossible. In Comparative Example 4 in which MI was 1.2 g / 10 min, the coating thickness on the upper and lower surfaces was uneven (that is, uneven thickness), resulting in the occurrence of coating breakage, and the long production was limited to about 1000 m. It was.

Examples 5 and 6
In Example 1, except that the hole width and thickness dimension of the final aperture nozzle were changed to 0.97 × 0.21 mm, the cross-sectional area of the nozzle hole was made larger than that in Example 1, and the degree of vacuum was −5 kPa. A thermoplastic resin-coated FRP filament was obtained in the same manner as in Example 1 (Example 5). The resin content of the obtained FRP part was 42 Vol. %, The width and thickness dimensions were 1.02 × 0.20 mm.
Next, except that 1 part by mass of calcium carbonate (NS # 200, average particle size of about 2.0 μm) manufactured by Nitto Flour Chemical Co., Ltd. was added to the thermosetting resin composition, and the degree of vacuum was −10 kPa. A thermoplastic resin-coated FRP filament was obtained in the same manner as in Example 5 (Example 6). The resin content of the obtained FRP part was 41 Vol. %, The width and thickness dimensions were 1.02 × 0.20 mm.
The FRP shape of each of the thermoplastic resin-coated FRP filaments of Examples 5 and 6 was good.

Comparative Example 5
In Example 1, heat was applied in the same manner as in Example 1 except that the hole width and thickness of the final aperture nozzle were changed to 1.10 × 0.25 mm and the cross-sectional area of the nozzle hole was made larger than that in Example 1. A plastic resin-coated FRP filament was obtained, but the resin content of the obtained FRP part was 57 Vol. %, When the pressure sizing was performed by the parallel sizing roller 10, the thermosetting resin flowed back to the coating die side, and the thermosetting resin contacted the molten coating cone. As a result, continuous production was impossible.

Comparative Example 6
A thermoplastic resin-coated FRP filament was obtained in the same manner as in Example 1 except that the aperture nozzle group and the final aperture nozzle were circular and the hole shape of the final aperture nozzle was φ0.48 mm. The resin content of the obtained FRP part was 31 Vol. %, The cross-sectional shape is as shown in the cross-sectional photograph of FIG. 8, the upper and lower sides of the long side are not parallel, and are elliptical, and the presence of the reinforcing fiber is non-uniform even in the FRP part, and the shape is The thermosetting resin was scattered and the shape uniformity was inferior compared with the FRP part by Example 1 of this invention.
The conditions and shapes of the above examples and comparative examples are collectively shown in Table 2.

  Under the manufacturing conditions of the comparative example, entanglement of reinforcing fibers, occurrence of foaming phenomenon due to the degree of decompression, tearing of the thermoplastic coating resin, unevenness of reinforcing fibers inside the FRP, and the like occurred. On the other hand, none of the production problems occurred under the conditions of the examples, and the FRP thermoplastic coated wire having a rectangular FRP portion and a short side of less than 0.3 mm, which could not be produced conventionally, was obtained. It was.

According to the manufacturing method of the present invention, a substantially rectangular thermoplastic resin-coated FRP filament, the upper and lower sides on the long side of the substantially rectangular cross section are parallel to each other, and the reinforcing fibers are uniformly dispersed Since a substantially rectangular thermoplastic resin-coated FRP filament can be obtained with high productivity and high yield, it can be used as a manufacturing method for a tension member of a drop optical fiber cable or a small-diameter FRP filament. It can be used effectively.
Since the substantially rectangular thermoplastic resin-coated FRP filament of the present invention has uniformity in the longitudinal direction, even when it is used as a tension member of a drop optical fiber cable, manufacturing troubles and It can be effectively used as a tension member for a drop optical fiber cable with no problem in quality and stable in productivity and quality.
The optical fiber cable according to the present invention can be effectively used as a non-metallic drop optical fiber cable that has a small minimum bending radius and is light and thin.

1, 43 Thermoplastic resin-coated FRP filaments (FRPTM with coating)
DESCRIPTION OF SYMBOLS 1a Uncured FRP filament 1b Thermoplastic-resin-coated uncured FRP filament 2 Tension bar 3 Tension adjustment guide 4 Guide bar 5 Resin impregnation tank 6 Drawing nozzle group 7 Melt extruder 8 Crosshead part 9 Parallel roll 10 Cooling water tank 11 Heat curing tank 12 Cooling water tank 13 Nelson roller (take-up machine)
14 Winding device 41 Drop optical fiber cable 42 Optical fiber core wire 43 FRPTM with substantially rectangular coating
44 Messenger wire (support wire)
45 FRP portion 46 covering portion 47 main body covering portion 48 notch 49 narrow width portion 60 final throttle nozzle 61 water supply pipe 62 drainage pipe 90 resin conduit portion 91 annular die 93 pressure reducing pipe connection end 94 inside of cone-shaped thermoplastic resin 95 cone Thermoplastic resin (coated cone)
F Reinforcing fiber bundle B Bobbin R Two non-rotating bars H Tip section TB1 First tension bar DB Dancer (oscillator)
G Slit-shaped guide T Contact between uncured linear material and coating resin

Claims (8)

An impregnation step (1) of impregnating a reinforcing fiber bundle made of organic synthetic fiber with an uncured thermosetting resin composition, a squeezing nozzle having a rectangular hole shape for the reinforcing fiber bundle impregnated with the thermosetting resin composition Using the drawing process (2), which is shaped into a predetermined rectangular shape, the molten thermoplastic resin is discharged in a cone shape from an annular die onto the outer peripheral surface of the drawn rectangular uncured filament. A covering step (3) for forming a covering layer, a sizing step (4) for forming a flat shape by pressing with parallel rolls of a predetermined gap, and a cooling and solidifying step for cooling and solidifying the covering layer by introducing it into a cooling water bath ( 5) A method for producing an FRP filamentous article comprising a heat curing step (6) for curing the thermosetting resin,
In the impregnation step (1), the reinforcing fiber bundle made of organic synthetic fiber is pulled out from the bobbin around which the reinforcing fiber bundle is wound, and the tension is reduced to 40 cN or more and 280 cN or less per reinforcing fiber bundle. The reinforcing fiber bundle is opened in a substantially untwisted state and introduced into an impregnation tank containing a thermosetting resin, the resin content of the FRP filament is 45% by weight or less, and the coating Step (3) is an inner side of a cone-shaped thermoplastic resin in which a polyolefin-based thermoplastic resin having an MI of 2 g / 10 min or more is discharged from an annular die before contacting the outer periphery of the rectangular uncured filament. A method for producing a substantially rectangular thermoplastic resin-coated FRP filament having a short side of the FRP portion in the longitudinal vertical cross section of less than 0.3 mm, characterized in that the coating is coated in a reduced pressure state. In the impregnation step (1), the means for opening the reinforcing fiber bundle in a substantially non-twisted state is a method of introducing the reinforcing fiber bundle before introducing the impregnation tank containing the thermosetting resin from the winding bobbin for feeding the reinforcing fiber bundle. 2. The substantially rectangular shape according to claim 1 , wherein a tension adjustment guide is provided between the guides, and all the guides including the tension adjustment guide are non-rotating guide bars having a diameter of 20 mm or less, and the surface roughness Ra is 1 μm or less. A method for producing a thermoplastic resin-coated FRP filament having a shape. The method for producing a substantially rectangular thermoplastic resin-coated FRP filament according to claim 2, wherein the guide bar is mirror-finished hard chrome plated. The said thermosetting resin is vinyl ester resin, The manufacturing method of the substantially rectangular-shaped thermoplastic resin coating | cover FRP filament in any one of Claims 1-3. The substantially rectangular thermoplastic resin-coated FRP wire according to any one of claims 1 to 4, wherein the organic elastic fiber has a tensile elastic modulus of 360 cN / dtex or more and an elongation at break of 3.5% or more. Manufacturing method of the article. The method for producing a substantially rectangular thermoplastic resin-coated FRP filamentous material according to any one of claims 1 to 5, wherein the organic synthetic fiber is an aromatic polyamide fiber. A substantially rectangular thermoplastic resin-coated FRP filament obtained by the production method according to claim 1. A drop optical fiber cable comprising the substantially rectangular thermoplastic resin-coated FRP filament according to claim 7 as a tension member.