JP2006145847A - Secondary coated optical fiber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary coated optical fiber which is easy to selectively remove only its UV curing resin cover provided as the overcoat layer. <P>SOLUTION: This is a secondary coated optical fiber 10 having a 1st cover 12 of UV curing resin of approximately 250 μm in an outside diameter in the outer periphery of an optical fiber 11 and a 2nd UV curing resin cover 13 formed on it approximately 500 μm large in an outside diameter containing a fatty acid based lubricant 0.5 to 5 weight%. Alternatively, it is a secondary coated optical fiber having a 1st cover of UV curing resin of approximately 250 μm in the outside diameter in the outer periphery of the optical fiber and a 2nd UV curing resin cover formed on it through a coated liquid lubrication layer and formed approximately 500 μm large in the outside diameter. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical fiber core wire used for an optical fiber cord, an optical drop cable or the like, and more specifically, a first coating having an outer diameter of approximately 250 μm and a second coating having an outer diameter of approximately 500 μm on the optical fiber. The present invention relates to an optical fiber core that is provided with a coating in order and that is excellent in the selective coating removal property of a second coating.

  Conventionally, as an optical fiber core wire used for an optical fiber cord, an optical drop cable, etc., an outer diameter of about 250 μm is obtained by coating an optical fiber mainly composed of quartz glass with an outer diameter of 125 μm with an ultraviolet curable resin. Such optical fiber cores are widely used for applications such as optical fiber cords and optical drop cables. Since this optical fiber core is thin, easy to bend and break, it is necessary to pay close attention to its handling during wiring work and connection work in the field.

  Therefore, in order to improve handling at the time of operation, a conventional optical fiber core having an outer diameter of about 250 μm and an overcoat made of an ultraviolet curable resin so that the outer diameter is about 500 μm has been proposed. (For example, refer to Patent Document 1). By increasing the diameter, it is intended to increase the rigidity and to improve the handleability.

  However, such an optical fiber core having an outer diameter of about 500 μm has improved the handleability during work due to the increase in diameter, but has caused the following problems.

  That is, in recent years, when connecting optical fiber core wires, a so-called mechanical splice method, in which optical fibers are butted and mechanically connected, has come to be used as a simple and inexpensive connection method. If such a method is applied to the above-described optical fiber core having an outer diameter of about 500 μm, it is necessary to selectively remove only the outer overcoat layer due to restrictions on the connecting device and tools used. There is. That is, the connection is made with only the coating having an outer diameter of about 250 μm left on the optical fiber.

  However, until now, there has been no optical fiber core having an outer diameter of about 500 μm that takes into account the selective removal of only the outer overcoat layer. Even with a general-purpose non-heated coating removal tool called a stripper, selective removal of the overcoat layer was difficult.

That is, in the heating type coating removing apparatus, all the coating up to the optical fiber is removed. On the other hand, the microstripper is a general-purpose non-heating type coating removal tool having two blades at the top and bottom, and the blade tips of the two blades are provided with semicircular dents, and the two blades are optical fibers. The sheath is cut and removed by moving the two blades in the length direction of the optical fiber core in this state by biting into the sheath of the core wire from both the upper and lower directions. The diameter of the dent of the blade edge can be changed as appropriate according to the diameter. However, in the above-described optical fiber core having an outer diameter of about 500 μm, the adhesion between the UV curable resin coating on the optical fiber and the overcoat layer is strong. Even if it is intended to selectively remove the inner UV curable resin coating, it will be removed together with the overcoat layer.
JP 2003-241033 A

  The present invention has been made to solve such a problem of the prior art, and a coating having an outer diameter of about 250 μm made of an ultraviolet curable resin is provided on an optical fiber, and an ultraviolet coating is further formed thereon as an overcoat layer. An optical fiber core that can be selectively and easily removed only from a coating made of an ultraviolet curable resin provided as an overcoat layer in an optical fiber core having an outer diameter of about 500 μm provided with a coating made of a curable resin The purpose is to provide.

  In order to achieve the above object, the optical fiber core according to claim 1 of the present application is provided with a first coating made of an ultraviolet curable resin having an outer diameter of about 250 μm on the outer periphery of the optical fiber, and on the first coating. The second coating having an outer diameter of about 500 μm and comprising an ultraviolet curable resin containing 0.5 wt% to 5 wt% of a fatty acid-based lubricant is provided.

  According to a second aspect of the present invention, in the optical fiber core according to the first aspect, the fatty acid lubricant is at least one selected from the group consisting of butyl stearate, a saturated fatty acid ester, and an aromatic alcohol fatty acid ester. It is characterized by.

  According to a third aspect of the present invention, in the optical fiber core according to the first or second aspect, the second coating is made of an ultraviolet curable resin having a Young's modulus at 23 ° C. of 30 MPa to 300 MPa. It is.

  According to a fourth aspect of the present invention, in the optical fiber core wire of the invention, a first coating made of an ultraviolet curable resin having an outer diameter of approximately 250 μm is provided on the outer periphery of the optical fiber, and a liquid lubricant coating layer is provided thereon. And a second coating having an outer diameter of approximately 500 μm is provided.

  The invention according to claim 5 is the optical fiber core according to claim 4, wherein the liquid lubricant is silicone oil.

  The invention according to claim 6 is the optical fiber core according to claim 4 or 5, wherein the second coating is made of an ultraviolet curable resin having a Young's modulus at 23 ° C. of 30 MPa to 800 MPa. It is.

  According to the optical fiber core of the present invention, a first coating made of an ultraviolet curable resin having an outer diameter of about 250 μm is provided on the outer periphery of the optical fiber, and an outer diameter made of an ultraviolet curable resin is about 500 μm. In the optical fiber core wire provided with the second coating, it is possible to selectively remove only the second coating using a micro stripper or the like, and it is easy to apply the core wire connection by so-called mechanical splice. Become.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a first embodiment of the optical fiber core of the present invention.

  As shown in FIG. 1, the optical fiber core wire 10 of the present embodiment has a structure in which a first coating 12 and a second coating 13 are sequentially provided on the outer periphery of an optical fiber 11 such as a quartz glass-based optical fiber. ing. The outer diameter of the optical fiber 11 is 125 μm, and the outer diameters of the first coating 12 and the second coating 13 are 250 μm and 500 μm, respectively.

  The first coating 12 is mainly for protection and strengthening of the optical fiber 11, and has a three-layer structure in which a primary layer 12a, a secondary layer 12b, and a colored layer 12c are formed in this order from the inside. Examples of the ultraviolet curable resin constituting each layer of the first coating 12 include urethane acrylate resins and epoxy acrylate resins.

  In contrast to the first coating 12, the second coating 13 is mainly for the purpose of improving the handleability and protecting from the environment. In the present invention, in addition to such a purpose, in order to be able to selectively remove only the second coating 13 using a coating removal tool such as a micro stripper, the second coating 13 is It comprises an ultraviolet curable resin containing 0.5 to 5% by weight of a fatty acid lubricant. Examples of the ultraviolet curable resin include urethane acrylate resins and epoxy acrylate resins. Examples of fatty acid lubricants include fatty acid ester lubricants such as butyl stearate, saturated fatty acid esters, aromatic alcohol fatty acid esters, and mixed systems thereof. These lubricants may be used alone or in combination of two or more.

  In the present invention, when the content of the fatty acid lubricant is less than 0.5% by weight, the adhesion between the first coating 12 and the second coating 13 is increased, and the selective removability of the second coating 13 is improved. The effect is reduced. On the other hand, when the content exceeds 5% by weight, the adhesion between the first coating 12 and the second coating 13 becomes too small, and the second optical fiber 11 coated with the first coating 12 is used. There is a risk of protrusion from the coating 13. A preferable range of the content of the fatty acid-based lubricant is 2% by weight to 3% by weight.

  In the present embodiment, the ultraviolet curable resin constituting the second coating 13 preferably has a Young's modulus (JIS K 7113) at 23 ° C. of 30 MPa to 300 MPa, and more preferably 100 MPa to 300 MPa. More preferably, the pressure is 200 MPa to 300 MPa. If the Young's modulus (JIS K 7113) at 23 ° C. of the ultraviolet curable resin constituting the second coating 13 is less than 30 MPa, the coating may be cut during the coating removal operation, or burrs may be generated on the coating removal end face. In addition, problems such as stickiness of the surface and peeling of the coating with a slight external force occur, and the handleability deteriorates. On the other hand, when the Young's modulus exceeds 300 MPa, the coating removability of the second coating 13 decreases.

  In order to manufacture this optical fiber core wire 10, for example, an optical fiber 11 obtained by melt spinning an optical fiber preform is used for the primary layer 12a, the secondary layer 12b, the colored layer 12c, and the first layer. Each of the UV curable resins for the coating 13 may be applied in order and irradiated with UV to be cured.

  In the optical fiber core 10 configured as described above, the outer diameter made of an ultraviolet curable resin containing a fatty acid lubricant at a predetermined concentration on the first coating 12 made of an ultraviolet curable resin having an outer diameter of 250 μm. By providing the second coating 13 having a thickness of 500 μm, it is possible to selectively and easily remove only the second coating 13 using a coating removal tool such as a micro stripper. Is easy to connect. In addition, it is also possible to remove the 1st coating | coated 12 independently or with the 2nd coating | coated 13 as needed by using the coating removal tool from which a coating removal diameter differs.

  Next, another embodiment of the present invention will be described.

  FIG. 2 is a cross-sectional view according to the second embodiment of the present invention, and parts common to FIG.

  In the optical fiber core 20 according to the present embodiment, a second coating 131 made of an ultraviolet curable resin not containing a fatty acid-based lubricant is provided on the first coating 12 via a coating layer 14 of a liquid lubricant. Except for this point, the configuration is the same as that of the first embodiment shown in FIG.

  That is, the first outer layer with a 250 μm outer diameter having a three-layer structure in which the primary layer 12a, the secondary layer 12b, and the colored layer 12c are formed in this order from the inner side on the outer periphery of the optical fiber 11 made of quartz glass-based optical fiber or the like. A coating 12 is provided, and a second coating 131 having an outer diameter of 500 μm made of an ultraviolet curable resin and not containing a fatty acid lubricant is provided on the coating layer 14 of a liquid lubricant.

  Also in the optical fiber core 20 configured as described above, between the first coating 12 having an outer diameter of 250 μm made of an ultraviolet curable resin and the second coating 131 having an outer diameter of 500 μm made of an ultraviolet curable resin. By interposing the coating layer 14 of the liquid lubricant, it becomes possible to selectively and easily remove only the second coating 131 by using a coating removal tool such as a micro stripper. Fiber connection is easy. In addition, by using a coating removal tool having a different coating removal diameter, the first coating 12 can be removed alone or together with the second coating 131 as necessary.

  In order to manufacture this optical fiber core wire 20, for example, the optical fiber 11 obtained by melt-spinning an optical fiber preform is used for each of the primary layer 12a, the secondary layer 12b, and the colored layer 12c as described above. An ultraviolet curable resin is applied in order and cured by irradiating with ultraviolet rays to form a first coating 12 composed of three layers, and then a liquid lubricant is uniformly applied on the first coating 12 over the entire circumference of the first coating 12. The second UV-curable resin for the coating 131 may be further applied while being applied uniformly in the direction, and cured by irradiation with UV rays.

Silicone oil is suitable as the liquid lubricant used to form the coating layer 14 of the liquid lubricant. In particular, from the viewpoint of long-term reliability, it is preferable to use a non-polar and non-volatile silicone oil such as dimethyl silicone. . Further, the kinematic viscosity (25 ° C.) is preferably 10 cm ² / s or more. If the kinematic viscosity (25 ° C.) is less than 10 cm ² / s, it is difficult to stably coat the second coating 131. Become.

  In this embodiment, the ultraviolet curable resin constituting the second coating 131 preferably has a Young's modulus (JIS K 7113) at 23 ° C. of 30 MPa to 800 MPa, more preferably 100 MPa to 800 MPa. preferable. More preferably, it is 200 MPa-800 MPa. If the Young's modulus (JIS K 7113) at 23 ° C. of the ultraviolet curable resin constituting the second coating 131 is less than 30 MPa, the coating may be cut off during the coating removal operation, or burrs may be generated on the coating removal end face. In addition, problems such as stickiness of the surface and peeling of the coating with a slight external force occur, and the handleability deteriorates. On the other hand, when the Young's modulus at 23 ° C. exceeds 800 MPa, the removability of the second coating 131 decreases.

  In each of the embodiments described above, the first coating 12 has a three-layer structure of a primary layer 12a, a secondary layer 12b, and a colored layer 12c. In the present invention, the first coating 12 is a single layer. It may have a layer structure or a two-layer structure. Also, it may be four layers or more.

  FIG. 3 is a sectional view showing an example of an optical fiber cord using the optical fiber core of the present invention.

  In FIG. 3, this optical fiber cord includes one or a plurality of optical fiber cores 31 (two in the example in the drawing), and aramid fibers, polyarylate fibers, poly fibers assembled together with the optical fiber cores 31. From tensile strength fibers 32 such as paraphenylene benzobisoxazole fibers, polyester fibers, and nylon fibers, and an outer cover 33 formed by extruding a thermoplastic resin such as polyethylene or polyvinyl chloride into a pipe shape on the outer periphery thereof. It is configured. And the optical fiber core wire of the present invention as described above is used for the optical fiber core wire 31. Such an optical fiber cord is not only excellent in handleability of the optical fiber core 31, but is connected only to the second coating of the optical fiber core 31 using a coating removal tool such as a micro stripper for connection. Can be selectively and easily removed, and the optical fiber can be easily connected by a so-called mechanical splice.

  FIG. 4 is a cross-sectional view showing an example of an optical fiber cable using the optical fiber core of the present invention.

  This optical fiber cable is an optical fiber cable suitable for use as a so-called aerial optical drop cable, and as shown in the figure, is composed of a support line portion 41, a cable portion 42, and a connecting portion 43 for connecting them. ing. The support wire portion 41 is composed of a support wire 44 made of a steel wire or the like, and a jacket 45 provided on the outer periphery thereof. The cable portion 42 includes one or a plurality of optical fiber core wires 46 (one in the example in the drawing), and steel wires disposed in parallel above and below the optical fiber core wires 46 at intervals. A tensile strength body 47 made of G-FRP (glass fiber reinforced plastic), tensile strength fiber (aramid fiber, polyester fiber, etc.) reinforced plastic, etc., and a jacket 48 provided on the outside thereof.

  The outer sheath 45 of the support wire portion 41, the outer sheath 48 of the cable portion 42, and the connecting portion 43 are formed by batch extrusion of a thermoplastic resin such as polyethylene or polyvinyl chloride, and the outer sheath 48 of the cable portion 42. A notch 48a for tearing is provided at the center of the both sides of the optical fiber at the portion where the optical fiber core 46 is located. During the cable connection operation, the coated optical fiber 46 can be easily taken out by tearing the jacket 48 starting from the tearing notches 48a. The optical fiber core wire of the present invention as described above is used for the optical fiber core wire 46.

  Such an optical fiber cable is not only excellent in the handleability of the optical fiber core 46 but is also connected only to the second coating of the optical fiber core 46 using a coating removal tool such as a micro stripper for connection. Can be selectively and easily removed, and the optical fiber can be easily connected by a so-called mechanical splice.

  Next, although the Example of this invention is described, this invention is not limited to a following example at all.

Examples 1-6
An optical fiber core having the structure shown in FIG. 1 was manufactured.
That is, a first three-layer structure comprising a primary layer 12a, a secondary layer 12b, and a colored layer 12c in this order from the inside on a quartz glass-based SM optical fiber 11 having an outer diameter of 125 μm using a urethane acrylate-based ultraviolet curable resin. A Young's modulus (23 ° C.) containing Loxiol G71 (trade name of a composite ester lubricant, manufactured by Henkel) as a lubricant is further formed on the coating 12 (outer diameter 250 μm). ) Is 250 MPa urethane acrylic UV curable resin (A) or Young's modulus (23 ° C.) is 700 MPa urethane acrylic UV curable resin (B) to form second coating 13 having an outer diameter of 500 μm. .

Comparative Examples 1-4
An optical fiber core was manufactured in the same manner as in the above example except that the material for forming the second coating 13 was changed as shown in Table 1.

Examples 7 and 8
An optical fiber core having the structure shown in FIG. 2 was manufactured.
That is, a first three-layer structure comprising a primary layer 12a, a secondary layer 12b, and a colored layer 12c in this order from the inside on a quartz glass-based SM optical fiber 11 having an outer diameter of 125 μm using a urethane acrylate-based ultraviolet curable resin. After the coating 12 (outer diameter 250 μm) was formed, KF-96-20CS (trade name of silicone oil, manufactured by Shin-Etsu Chemical Co., Ltd .; viscosity 20 cm ² / s) as a liquid lubricant was thinly applied to the surface. A urethane acrylic ultraviolet curable resin (A) having a Young's modulus (23 ° C.) of 250 MPa or a urethane acrylic ultraviolet curable resin (B) having a Young's modulus (23 ° C.) of 700 MPa is coated and cured by ultraviolet irradiation. A second coating 131 having an outer diameter of 500 μm was formed.

  MICRO-STRIP (registered trademark) manufactured by MICRO ELECTRONICS was used for the optical fiber cores obtained in each of the above examples and comparative examples, and the second coating was performed under conditions of a removal length of 50 mm and a tensile speed of 500 mm / min. Attempts were made to remove 13 and 131, and the removability was evaluated. The optical fiber core cut into a length of 1 m was held for 3 cycles in a temperature range of −30 ° C. to + 70 ° C., and then the optical fiber 11 from the second coatings 13 and 131 (the first coating 12 was coated). The amount of protrusion in the state) was measured. These measurement results are shown in Tables 1 and 2 together with the Young's modulus of the material constituting the second coatings 13 and 131.

  As is apparent from the above results, in particular, the second coating is made using an ultraviolet curable resin containing 0.5 to 5% by weight of a fatty acid-based lubricant and having a Young's modulus (23 ° C.) of 300 MPa or less. And the optical fiber cores of Examples 7 and 8 in which silicone oil is applied on the first coating and the second coating is provided on the first coating. In addition to being excellent in selective removability, the protruding amount of the optical fiber was less than 1 mm and had good characteristics. On the other hand, in Comparative Example 2 in which the content of the fatty acid lubricant is too small, and in Comparative Examples 3 and 4 in which the content of the fatty acid lubricant is not blended and the silicone oil is not applied, the coating removal property is poor. Further, in Comparative Example 1 in which the content of the fatty acid lubricant is excessive, although the coating removal property is good, an increase in the protruding amount of the optical fiber is recognized, which causes a problem in practical use.

Sectional drawing which shows one Embodiment of the optical fiber core wire of this invention. Sectional drawing which shows other embodiment of the optical fiber core wire of this invention. Sectional drawing which shows an example of the optical fiber cord using the optical fiber core wire of this invention. Sectional drawing which shows an example of the optical fiber cable using the optical fiber core wire of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10, 20, 31, 46 ... Optical fiber core wire, 11 ... Optical fiber, 12 ... 1st coating | cover, 12a ... Primary layer, 12b ... Secondary layer, 12c ... Colored layer, 13, 131 ... 2nd coating | cover, 14 ... Liquid lubricant coating layer

Claims (6)

  A first coating made of an ultraviolet curable resin having an outer diameter of approximately 250 μm is provided on the outer periphery of the optical fiber, and an outer layer made of an ultraviolet curable resin containing 0.5 wt% to 5 wt% of a fatty acid-based lubricant is formed thereon. An optical fiber core wire provided with a second coating having a diameter of approximately 500 μm.   2. The optical fiber core wire according to claim 1, wherein the fatty acid lubricant is at least one selected from the group consisting of butyl stearate, saturated fatty acid ester and aromatic alcohol fatty acid ester.   The optical fiber core wire according to claim 1 or 2, wherein the second coating is made of an ultraviolet curable resin having a Young's modulus at 23 ° C of 30 MPa to 300 MPa.   A first coating made of an ultraviolet curable resin having an outer diameter of approximately 250 μm is provided on the outer periphery of the optical fiber, and an outer diameter of an ultraviolet curable resin having an outer diameter of approximately 500 μm is provided on the first coating via a liquid lubricant coating layer. An optical fiber core wire provided with a second coating.   5. The optical fiber core wire according to claim 4, wherein the liquid lubricant is silicone oil.   6. The optical fiber core wire according to claim 4, wherein the second coating is made of an ultraviolet curable resin having a Young's modulus at 23 ° C. of 30 MPa to 800 MPa.

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