JPH0456810A - Manufacturing method of spacer for optical cable - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method of manufacturing a spacer for accommodating an optical fiber in an optical cable, and particularly relates to a method of manufacturing a spacer that improves shape stability and productivity. .

(Prior art and problems to be solved) Conventionally, as a method of coating a mixture of reinforcing fiber material impregnated with an uncured thermosetting resin with a thermoplastic resin,
A method disclosed in Japanese Patent No. 43501 is known. In this method, a mixture of reinforcing fiber material impregnated with an uncured thermosetting resin is coated with a molten thermoplastic resin, and the coated surface resin layer is cooled and solidified to form an internally uncured state. .

This method has the problem that the molded product cannot be manufactured with sufficient precision because the thermoplastic resin is coated before the inside is cured.

Furthermore, as one of the conventional methods for manufacturing an optical cable spacer, a method disclosed in Japanese Patent Application Laid-Open No. 84-23211 is known. In this method, the outer circumference of the Tenseen member is coated with thermoplastic resin by extrusion to form an inner layer with a perfect circular cross section. After this is cooled to below its softening point, a rotating die is used to cover the outer circumference of the inner layer with thermoplastic resin of the same type as above. The outer layer having grooves is formed by extrusion coating with a poor resin.

However, in the above method, since the thermoplastic resin in the inner layer is once cooled and solidified, there is a problem in that the variation in shape impairs the stability of the originally required shape of the spacer.

(Means for Solving the Problems) The present invention solves the above-mentioned problems and provides a method for manufacturing an optical cable spacer that improves shape stability and productivity. An inner layer of thermoplastic resin is extruded and coated in a circular shape on the outer periphery of a fiber-reinforced resin tensile strength body obtained by impregnating an unbored thermosetting resin, molding it into a circular shape, and heating and curing it. A resin of the same type as the above-mentioned thermoplastic resin is extruded and coated thereon using a rotating die to provide an outer layer having a plurality of concave grooves in the longitudinal direction of the outer periphery.

(Example) FIG. 1 is a cross-sectional view of an optical cable spacer obtained by the manufacturing method of the present invention. In the drawings, (1) is a fiber-reinforced resin tensile strength body made by impregnating a reinforcing fiber material such as aramid fiber with an uncured thermosetting resin and curing it by heating;
(2) is an inner layer extruded from a thermoplastic resin such as high-density polyethylene, and (3) is an outer layer extruded from the same type of thermoplastic resin as above.By using a rotating die for extrusion, a spiral shape is formed in the longitudinal direction. Alternatively, a plurality of concave grooves (3a) extending in an SZ shape can be formed at the same time.

FIG. 2 is an explanatory diagram of a specific example of the manufacturing method of the present invention.

A reinforcing fiber material (12) is fed out from a supply device (11), guided to an impregnation tank (13), and impregnated with an uncured thermosetting resin (14). Thereafter, it is formed into a circular shape through a forming die (15), and then introduced into a heating furnace (16) where it is heated and hardened. Thereafter, the inner resin layer (2) is circularly coated with thermoplastic resin discharged from a conventional extruder A (C+7), and immediately extruder B (1) equipped with a rotary die (18a)
8) and covered with a resin of the same type as the thermoplastic resin discharged from the rotating die (18a) of the extruder (18) to form an outer layer having a plurality of concave grooves (3a) in the longitudinal direction on the outer periphery. Then, cool it down (19) and take it back to the capstan (20).
The film is taken up by the winding drum (21).

(Function) In the manufacturing method of the present invention described above, a reinforcing fiber material is impregnated with an uncured thermosetting resin, and then shaped into a circular shape.
Since it is heated and cured, a fiber tensile strength body with a stable shape and high precision can be obtained.

On top of that, an inner layer of thermoplastic resin is coated in a circular shape, and an outer layer of the same type of resin as the thermoplastic resin is immediately coated without cooling, so the shape of the resin layer is stable, and the overall shape is highly accurate and stable. A shaped spacer is obtained.

(Prototype example) Using aramid fiber as a reinforcing fiber material, it is impregnated with uncured unsaturated polyester resin, molded into a circular shape, and then introduced into a heating furnace to be heated and hardened to create a shape with an outer diameter of 2.3 mm.
A tensile strength body made of fiber-reinforced resin was obtained.

High-density polyethylene was extruded and coated in a circular shape on the fiber-reinforced resin tensile strength body using a 65 mm φ extruder, and the outer diameter of the inner resin layer was 7 mm. Using an extruder equipped with a die, the same high-density polyethylene as above was extruded and coated, and the outer periphery was coated with a depth of 2.15 mm and a width of 1.5 mm.
An outer resin layer having eight 2 mm spiral concave grooves was formed to produce a spacer as shown in FIG. 1. The dimensions of the resulting concave grooves were stable within ±50 μm.

Using the above spacer, as shown in FIG.
An optical cable was manufactured by storing a laminate in which a plurality of sheets of 0) were laminated, applying a pressing tape (4) on the outer periphery of the spacer, and further applying a plastic outer coating layer (5).

The optical fibers of the obtained optical cables are all 1.55μ.
The variation in transmission loss in the garden zone is within 0.03dB/Km,
It was in good condition.

(Effects of the Invention) As explained above, according to the method for manufacturing an optical cable spacer of the present invention, a spacer with high dimensional accuracy and stable shape can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a spacer obtained by the manufacturing method of the present invention. FIG. 2 is an explanatory diagram of a specific example of the manufacturing method of the present invention. FIG. 3 is a cross-sectional view of an optical cable using the spacer of FIG. 1. DESCRIPTION OF SYMBOLS 1... Fiber-reinforced resin tensile strength body, 2... Inner resin layer, 3... Outer resin layer, 3a... Concave groove 11... Supply device, 12... Reinforcing fiber material, 13 ... Impregnation tank, 14 ... Thermosetting resin, 15 ... Molding die, 1G ... Heating furnace, 17.18 ... Extruder, 18a
... Rotating die, 19... Cooling tank, 20... Taking-off capstan, 21... Winding drum.

Claims (1)

[Claims] (1) A reinforcing fiber material is impregnated with an uncured thermosetting resin, molded into a circular shape, and then heated and cured. The inner layer of thermoplastic resin is placed in a circular shape on the outer periphery of a fiber reinforced resin tensile strength body. For an optical cable, the thermoplastic resin is coated by extrusion, and then a resin of the same type as the above thermoplastic resin is extruded and coated using a rotating die, and an outer layer having a plurality of concave grooves in the longitudinal direction of the outer periphery is provided. Method of manufacturing spacers.