JP4156498B2 - Manufacturing method of FRP for drop optical cable - Google Patents

Description

  The present invention relates to an FRP manufacturing method and a drop optical fiber cable using the FRP, and more particularly to an FRP manufacturing method suitable for a drop optical cable used for FTTH and the like.

  With the arrival of an information society, the transmission information capacity of the Internet and the like has increased, and the FTTH system in which optical fiber cables are laid to subscribers such as buildings and houses is rapidly progressing.

  As a drop optical cable for FTTH, a cable using a metal wire, for example, a single steel wire having a diameter of about 0.4 mm, has been proposed as a tensile body. (See Patent Document 1)

  However, if a metal wire is used for the strength member, grounding work is required in the termination cabinet due to the problem of lightning surge. Grounding work is time-consuming and expensive, and is an obstacle to the spread to each home.

  For this reason, so-called IF (Induction Free) drop optical cables using non-derivatives such as GFRP as the strength members are becoming mainstream.

However, the technical problems described below have been pointed out in the conventional IF type drop optical cable.
JP 2001-337255 A

  In other words, the IF type drop optical cable has the plus side that grounding work is unnecessary and contributes to the reduction of construction time and construction cost. On the other hand, since the tensile strength body is mainly FRP, the bending strength is larger than that of metal wires. There is also the downside of easily breaking at the diameter.

  In actual home use, the end user's general household wiring is usually laid along the wall, so when laying in the corner, it is preferred to lay along the wall exactly. Therefore, there is an increasing demand for reducing the bending radius of the drop optical cable.

  In order to reduce the bending diameter leading to breakage in this type of cable, the FRP diameter may be reduced. However, when the reinforcing fibers are the same, there arises a problem that the tensile strength is reduced.

  In order to avoid this problem, a method using an organic fiber having a high elastic modulus such as a polyparaphenylene benzobisoxazole fiber can be considered as the reinforcing fiber.

  However, in this method, even if the FRP diameter is reduced, the necessary tensile strength can be ensured and the bending radius can be reduced. However, in general, in the case of FRP using a highly elastic organic fiber as the reinforcing fiber, the compression modulus is low. Since it is as low as 1/2 to 1/4 of general-purpose GFRP and the contact area with the main body resin is reduced by reducing the diameter, another problem that the anti-shrinkage force is insufficient occurs.

  In the drop optical cable, the anti-shrinkage force acts as a tension rod, and the strength member also serves to protect the optical fiber by suppressing the shrinkage of the main body resin.

  Therefore, if the diameter of the strength member is unduly reduced to reduce the contact area or the cross-sectional area ratio with respect to the main body resin, there is a high possibility that the anti-shrink force is insufficient even if the tensile strength can be maintained.

The present invention has been made in view of such problems, and an object of the present invention is to provide a method for manufacturing an FRP for a drop optical cable that can reduce the bending radius without reducing the diameter. There is.

  In order to achieve the above object, the present invention impregnates a reinforcing fiber with a thermosetting resin, and after making a predetermined resin content with a squeezing nozzle, the thermosetting resin is in an uncured state on the outer periphery thereof. The outer layer portion of the two layers is formed by coating with a thermoplastic resin, and then the thermosetting resin in the FRP portion is heat-cured, and then only the outer layer portion covered by the two layers is peeled and removed. A method for producing FRP with a thermoplastic resin coating, wherein a polyethylene resin is used as the thermoplastic resin of the inner layer portion, the thermoplastic resin of the outer layer portion is not compatible with the polyethylene resin, and the polyethylene A thermoplastic resin having a melting point or a softening point higher than that of the resin by 20 ° C. or higher was used, and the cross-sectional shape of the FRP portion was rectangular.

  According to the manufacturing method of the drop optical cable FRP configured as described above, the coated FRP for the drop cable is formed into a rectangular shape, and the outer layer portion of the two layers is coated with a thermoplastic resin, and the outer layer portion is formed after thermosetting. For example, even if steam curing is performed, surface roughness does not occur and surface smoothness is kept high.

  For this reason, there is a possibility that a sizing step on the surface is not required, and it is possible to apply a curing method other than vapor curing, for example, curing by contacting a heating roller.

  When the cross-sectional area of the FRP portion is the same, the rectangular shape has a longer circumference than the circular shape, and the bonding area between the FRP and the coating increases. Accordingly, the anti-shrink property is improved as compared with the case of the circular cross section.

  Further, if the cross-sectional shape of the FRP portion is a rectangle, the rectangle can be easily bent in the thickness direction, and the minimum bending diameter can be reduced. In addition, since it is difficult to bend and break in the width direction, it is not easily broken during construction.

In the present invention, high-pressure steam can be used for the heat curing.
Moreover, the said heat curing can also be performed by making it contact with a heating roller.

  The FRP with a thermoplastic resin coating obtained by the production method of the present invention can be used as a tensile body of a drop optical cable.

According to the method for producing an FRP for a drop optical cable according to the present invention, an FRP with a thermoplastic resin coating excellent in surface smoothness can be obtained without performing a shaping step .

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an example of a drop optical cable obtained by a method for manufacturing a drop optical cable using FRP according to the present invention. The drop optical cable 1 shown in the figure includes an optical fiber core wire 2, a strength member 3, and a messenger wire 4.

  The tensile body 3 is formed in a flat rectangular cross section in which the FRP portion 5 made of fiber reinforced thermosetting resin is covered with an inner coating portion 6 made of a thermoplastic resin, and the pair of tensile strength bodies 3 are optical fiber cores. The lines 2 are arranged on the same axis with a predetermined interval above and below the line 2 so as to sandwich them.

  The messenger wire 4 is disposed above one of the coated tensile bodies 3, and the optical fiber core wire 2, the coated tensile body 3, and the messenger wire 4 are configured to be collectively covered with a main body coating portion 7 made of a thermoplastic resin. I have. A pair of notches 8 are formed on the body covering portion 7 so as to face each other on both sides of the optical fiber core wire 2.

  Further, a circular main body covering portion 7 is provided on the outer periphery of the messenger wire 4, and the messenger wire 4 is connected by a narrow width portion 9 so as to be separable from other portions.

  The drop optical cable 1 configured as described above is installed between utility poles using the messenger wire 4, and when pulling into the subscriber's house, first, the narrow portion 9 is cut to separate the messenger wire 4. Next, the optical fiber core wire 2 is separated from the notch 8 and the subscriber side is connected to the core wire 2.

  In the case of the present embodiment, the strength member 3 is obtained by applying an inner coating portion 6 made of a thermoplastic resin to the FRP portion 5 made of fiber reinforced thermosetting resin, and with respect to the central axis O of the cross section of the drop optical cable 1. The central axis of the optical fiber core 2, the central axis of the messenger wire 4, and the central axis in the width direction of the pair of strength members 3 formed in a rectangular cross section are arranged coaxially.

  Such a tensile body 3 is obtained by impregnating a reinforcing fiber with a thermosetting resin and adjusting the resin content with a squeezing nozzle, and then setting the thermoplastic resin on the outer periphery of the thermosetting resin in an uncured state. Then, the inner layer portion 6 and the outer layer portion of the two layers are formed by coating, and then the thermosetting resin of the FRP portion 5 is heated and cured, and then only the outer layer portion covered by the two layers is peeled and removed. Manufactured as FRP with plastic resin coating.

  In this case, a polyethylene resin is used for the thermoplastic resin of the inner layer portion 6, the thermoplastic resin of the outer layer portion is not compatible with the polyethylene resin, and has a melting point or softening point higher than that of the polyethylene resin by 20 ° C. A thermoplastic resin is used.

  In this case, the reinforcing fiber of the FRP unit 5 is appropriately selected from, for example, glass fiber, aramid fiber, polyarylate fiber, polyparaphenylene benzobisoxazole (PBO) fiber, and the like.

  The thermosetting resin that can be used for binding the reinforcing fiber of the present invention is generally a terephthalic acid-based or isophthalic acid-based unsaturated polyester resin, a vinyl ester resin (such as an epoxy acrylate resin), or an epoxy resin. These are used by adding a curing catalyst or the like, and vinyl ester resins (such as epoxy acrylate resins) are particularly preferred from the viewpoint of physical properties such as heat resistance.

  In addition, when the glass yarn is used as the reinforcing fiber, the FRP portion 5 is desirably a fiber reinforced thermosetting resin cured product having an outer diameter of 0.9 mm or less from the viewpoint of bending resistance and diameter reduction (more preferably). Is 0.6 mm or less).

  High-pressure steam can be used for the heat curing of the FRP unit 5. In addition to this, heat curing can be carried out by contacting with a heating roller.

  The tensile body 3 having a rectangular cross section is arranged so that the thickness of the tensile body 3 becomes smaller with respect to the bending direction (left and right direction in FIG. 1) when the drop optical cable 1 is laid, thereby further increasing the bending radius. It can be made smaller and the laying property can be further improved.

  Specific examples of the present invention will be described below, but the present invention is not limited to the above examples or the following specific examples.

Example 1

  After impregnating 19 glass yarns of 22.5tex (ECE225-1 / 0 1.0Z R41 T: made by Nitto Glass Fiber) with thermosetting vinyl ester resin (Ester H-8100: made by Japan Composite), a squeezing nozzle Was drawn to a rectangular cross section of 0.9 mm × 0.3 mm.

  Subsequently, it was led to a crosshead die, extruded and coated with LLDPE (NUCG 5223: manufactured by Nihon Unicar), and immediately cooled with water to obtain a 1.2 mm × 0.6 mm substantially rectangular coated uncured FRP.

  Subsequently, it was led to a crosshead die, extruded and coated with FEP (NP-100: manufactured by Daikin Industries), and immediately cooled with water to obtain an uncured FRP of 1.5 mm × 0.9 mm coated substantially rectangular two layers.

  The resulting two-layer coating uncured FRP is guided to a steam curing tank, cured using high-pressure steam at 145 ° C., and then the outer layer coating, the FEP layer, is peeled off to provide a substantially rectangular coating of 1.2 mm × 0.6 mm FRP was obtained.

  The coated surface state of the obtained substantially rectangular coated FRP was smooth and did not cause foaming or clogging in the nipple or the like when the drop cable was produced.

Example 2

  After impregnating 14 glass yarns of 22.5tex (ECE225-1 / 0 1.0Z R41 T: made by Nitto Glass Fiber) with thermosetting vinyl ester resin (Ester H-8100: made by Japan Composite), the squeezing nozzle was used. It was drawn and formed into a circular cross section of φ0.5 mm.

  Subsequently, it was led to a crosshead die, covered with extrusion by LLDPE (NUCG 5223: manufactured by Nihon Unicar), and further covered by extrusion with FEP (NP-100: manufactured by Daikin Industries). After passing between the rollers and flattening, it was cooled with water to obtain a 1.3 mm × 0.7 mm substantially rectangular two-layer coated uncured FRP.

  The obtained two-layer coating uncured FRP is guided to a steam curing tank, cured using high-pressure steam at 145 ° C., and then the outer layer coating FEP layer is peeled off to obtain a substantially rectangular coating of 1.1 mm × 0.5 mm. FRP was obtained.

  The coated surface state of the obtained substantially rectangular coated FRP was smooth and did not cause foaming or clogging in the nipple or the like when the drop cable was produced.

Example 3

  A coated FRP having a substantially rectangular cross section was obtained in the same manner as in Example 1 except that the heat curing was performed by contacting the heated roller adjusted to 150 ° C. The coated surface state of the obtained substantially rectangular coated FRP was smooth and did not cause foaming or clogging in the nipple or the like when the drop cable was produced.

Comparative Example 1

  A substantially rectangular coated FRP was obtained in substantially the same manner as in Example 1 except that the thermoplastic resin coating was coated only with LLDPE (NUCG 5223: Nippon Unicar).

  The coated surface of the obtained substantially rectangular coated FRP has many crater-like irregularities that occurred when the steam was formed into water droplets. It was impossible.

Comparative Example 2

  Except for coating the thermoplastic resin coating only with LLDPE (NUCG 5223: manufactured by Nihon Unicar), production was attempted in substantially the same manner as in Example 2, but the coating resin adhered to the heating roller and was continuously It was impossible to manufacture.

  According to the method for manufacturing an FRP for a drop optical cable according to the present invention, an FRP with a thermoplastic resin coating excellent in surface smoothness can be obtained without performing a shaping step, and according to the present invention. According to the drop optical fiber cable using FRP, since the cross-sectional shape of the FRP portion is rectangular, the drop optical cable has a small minimum bending diameter and excellent anti-shrinkage force. It can be used effectively.

It is sectional drawing which shows an example of the drop optical cable concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drop optical cable 2 Optical fiber core wire 3 Strength member 4 Messenger wire 5 FRP part 6 Inner layer part 7 Main body coating part 8 Notch 9 Narrow part

Claims (3)

After impregnating the reinforcing fiber with a thermosetting resin and adjusting the resin content with a squeezing nozzle,
With the thermosetting resin in an uncured state, the outer periphery of the two layers is formed by coating the outer periphery with a thermoplastic resin, and then the thermosetting resin in the FRP portion is heated and cured. Later, a method for producing FRP with a thermoplastic resin coating, which peels and removes only the outer layer part coated on two layers,
A polyethylene resin is used as the thermoplastic resin of the inner layer portion, the thermoplastic resin of the outer layer portion is not compatible with the polyethylene resin, and has a melting point or a softening point higher than that of the polyethylene resin by 20 ° C. A method for producing an FRP for a drop optical cable, wherein a plastic resin is used and the cross-sectional shape of the FRP portion is rectangular. The method for producing an FRP for a drop optical cable according to claim 1, wherein high-pressure steam is used for the heat curing. The method for producing an FRP for a drop optical cable according to claim 1, wherein the heat curing is performed by contacting with a heating roller.

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