JPS6029657B2 - Method for manufacturing reinforced optical fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a reinforced optical fiber, in which the optical fiber is reinforced with a long fiber and a thermosetting resin impregnated therein.

As a means of reinforcing the optical fiber, long fibers such as glass fibers or carbon fibers in a roving state are longitudinally attached to the outer periphery of the optical fiber that has been coated with the primary coating, and a thermosetting resin impregnated into the long fibers is applied. It has already been practiced to form a reinforcing layer around the outer periphery of the optical fiber by curing it using suitable heating means.

Conventionally, when manufacturing such reinforced optical fibers, the optical fibers and long fibers soaked in resin were passed through a cylindrical heating molding machine with an electric heater on the outer periphery, and the resin was thermoset inside the machine. When curing the resin in this way, it was necessary to apply a large tensile force to the long fibers at the inlet of the thermoforming machine in order to remove the excess resin impregnated into the longest fibers.

Due to this tensile force, the long fibers were finally broken at the inlet of the thermoforming machine. As a result, the line speed at which the optical fiber and the longest fiber are passed through the molding machine is kept low, making it impossible to manufacture reinforced optical fibers with high efficiency.

In view of the above-mentioned problems, the present invention makes it possible to remove the excess resin impregnated into long fibers without generating a large tensile force by the squeezing action of a die using ultrasonic vibration. The specific method will be explained with illustrations.

In FIG. 1, 1 is a supply bobbin for optical fiber 2;
3, 3, 3... are glass fibers made of micron glass filaments in a roving state.
..., a supply bobbin 5, a resin tank containing liquid (uncured) thermosetting resin 6, 7 a guide made of a batten, 9 ultrasonic transducers 10a, 101b The die 11 to which these are connected is a cylindrical molding machine having a heater 12 such as a band heater (electric heater) on the outer periphery.

In the above, the present invention unwinds and supplies the primarily coated optical fiber 2 from the supply bobbin 1, and from the supply bobbin 3, 3, 3... the glass fibers 4, 4, 4... in a roving state. ... is unwound and supplied, and these optical fibers 2 and glass fibers 4, 4, 4...
... is guided to a guide device 7 consisting of a batten or the like, but the glass fibers 4, 4, 4, etc. are immersed in the resin tank 5 before reaching the guide device 7, and then After impregnating the optical fiber 2 with a liquid resin 6 such as epoxy resin or polyester resin, the optical fiber 2 and each of the resin-impregnated glass fibers 4 and 4 are
, 4... pass through the guide 7.

In the guide device 7, the optical fiber 2 passes through the center and the resin-impregnated glass fibers 4, 4, 4, . . . surround it. Glass fibers 4, 4, 4... are pulled through to the next stage die 9, but this die 9 is an ultrasonic transducer 10a.
, 10b, an aperture effect as shown in FIG. 2 is produced.

In other words, the die 9 receiving ultrasonic vibration repeats vibrations in the optical fiber axis direction, such as moving forward in the direction of the arrow x in Figure 2 and backward in the direction of the arrow Y in the same figure, and then repeating vibrations in the direction of the optical fiber axis. When moving forward, the die 9 moves each glass fiber 4, 4,
Part of the resin 6 impregnated into 4 (surplus)
Since the resin 6 is pushed back in the direction of the arrow X, the excess resin 6 is not taken into the die 9, and the compressive force due to the inner periphery of the die becomes extremely small.

Therefore, the optical fiber 2 and the resin-impregnated glass fibers 4, 4, 4, etc., which are formed to a predetermined outer diameter by passing through the die 9, are in a state where the frictional resistance against the inner circumference of the die is small. can pass through dice 9,
As a result, these optical fibers 2 and glass fibers 4, 4
, 4, . . . in the direction of the arrow Z in FIG. 2 becomes sufficiently small, and no breakage of the glass fibers or the like occurs at this point. Furthermore, when the die 9 is in the above-mentioned vibration state, the liquid resin 6 penetrates into each part of each glass fiber 4, 4, 4, etc. due to its ultrasonic vibration, resulting in voids that cause strength defects. The optical fiber 2 and the glass fibers 4, 4, 4, . . . are filled with the resin 6. Optical fiber 2 and resin-impregnated glass fibers 4, 4, 4, formed by the above-mentioned die 9
... enters into the molding machine 11 immediately after the die, where the resin 6 is thermally cured by the heater 12 to obtain the reinforced optical fiber 13 also shown in FIG.

In addition, the optical fiber 2 and the glass fibers impregnated with oak resin 4, 4
, 4... pass through this molding machine 11,
Since these are molded to a predetermined diameter by the die 9, the compressive force and tensile force applied to the optical fiber 2, each glass fiber 4, 4, 4, etc. in the molding machine 11 are extremely small. Therefore, when passing through the molding machine 11, the glass fibers etc. will not break.
In addition, since excess resin has already been removed from each glass fiber 4, 4, 4, etc., a large amount of resin adheres to the inlet of the molding machine 11 and hardens, causing it to become an adjacent path. That doesn't happen either.

As explained above, the present invention involves arranging a plurality of long fibers impregnated with a thermosetting resin along the longitudinal direction of the outer periphery of an optical fiber, and the longest fiber impregnated with the resin along the longitudinal direction of the outer periphery of the optical fiber. When the fiber passes through the die, the excess resin is removed while applying ultrasonic vibration to the die, and then the impregnated resin remaining in the good length fiber is thermoset, so that the fiber passes through the die. There is no longer any excessive tensile force acting on the optical fiber or each long fiber during and after that time, and therefore the optical fiber or long fiber does not break, and since the breakage has been prevented, the reinforcement The production efficiency can be increased by increasing the speed of the line during optical fiber production.

[Brief explanation of the drawing]

FIG. 1 is a front view of a cutaway of a main part showing one embodiment of the method of the present invention, FIG. 2 is an enlarged cross-sectional view of the same main part, and FIG. 3 is a cross-sectional view of a reinforced optical fiber obtained by the method of the present invention. It is. 2...Optical fiber, 4...Glass fiber as long fiber, 6...Resin, 9...
・Dice, 10a, 10b... Ultrasonic vibrator,
11... Heating molding machine. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1. When a plurality of long fibers impregnated with a thermosetting resin are aligned along the longitudinal direction of the outer periphery of the optical fiber and then passed through a die to be molded, the optical fiber and the resin aligned along the outer periphery of the optical fiber are formed. A method for producing a reinforced optical fiber, which comprises passing the impregnated long fiber through a die subjected to ultrasonic vibration, and then thermosetting the thermosetting resin impregnated in the long fiber. .