JPH02103509A - Plastic optical fiber cord - Google Patents

Abstract

PURPOSE:To obtain the plastic optical fiber cord which decreases projection and recessed part of a bare fiber and a polyethylene (PE) coating material by coating the outer side of the plastic optical fiber cord consisting of a two- layered core-clad structure with a PE resin contg. a magnesium compd. CONSTITUTION:The magnesium compd. is mixed with the PE resin of the PE coating material 2 of the plastic optical fiber cord 1 consisting of the two- layered core-clad structure. For example, magnesium hydroxide, magnesium carbonate, and magnesium oxide are used as the magnesium compd. to be mixed with the PE resin. The PE resin mixed with 20 to 75wt.%, more prefer ably 50 to 65wt.% magnesium compd. to be mixed is preferably used. The plastic optical fiber cord which decreases the projection and recessed part even under extreme wet heat conditions and high temp. condition is obtd, in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to an improved plastic optical fiber barcode used as a medium for short distance optical transmission. More specifically, the present invention relates to a plastic optical fiber bar code in which bare wires do not protrude or retract on the end face of the plastic optical fiber bar code, which has been particularly required in recent years.

(Prior Art) In recent years, optical communication technology using plastic optical fiber bar codes as information transmission paths has progressed rapidly and has already reached the stage of practical use.

Plastic optical fibers are made of polymethyl methacrylate, a thermoplastic resin with excellent transparency, and have a concentric shape in which the core bone has a higher refractive index than the sheath, and light incident from one end of the fiber is concentric. is transmitted to the other end while being totally reflected at the core-sheath interface. Since the bare wires of such plastic optical fibers are thin and extremely weak, they are usually coated with polyethylene and used as plastic optical fiber bar codes.

However, the polyethylene coating of conventional plastic optical fiber barcodes causes bare wires to protrude and retract when heated or under humid heat conditions.

Conventionally, to fix a plastic optical fiber barcode, the covering material was stripped off from the plastic optical fiber barcode and inserted into the connector, but in this case, the plastic optical fiber barcode and bare wires were fixed with adhesive, which was complicated. This method requires a lot of work, and the solvent in the adhesive migrates to the bare wires of the plastic optical fiber bar code, causing cranks to occur in the bare wires of the plastic optical fiber bar code, resulting in a decrease in optical performance. On the other hand, in order to maintain optical performance and eliminate the trouble of stripping off the coating material, in recent years plastic optical fiber cords have been inserted directly into connectors, and the plastic optical fiber cords that protrude from the end face of the connectors have been developed. A method is being put into practical use that involves simply cutting the core and processing the edges, but in this case, there are problems in practical handling, such as protrusion and retraction between the core and the coating layer, which greatly changes the optical performance. be.

(Problems to be Solved by the Invention) An object of the present invention is to address the drawbacks of the conventional plastic optical fiber bar code, and to provide a plastic optical fiber bar code in which the protrusion and retraction of the bare wire and the polyethylene coating material are reduced. It is in.

(Means for Solving the Problems) As a result of extensive research, the present inventors found that when a magnesium compound was mixed with polyethylene resin, the adhesion between the bare plastic optical fiber and the coating layer was surprisingly improved. The present invention was completed by paying attention to the fact that the protrusion and retraction between the cord covering material and the bare wire is significantly reduced.

That is, the present invention provides a plastic optical fiber in which the outside of a plastic optical fiber bar cord having a double core-sheath structure is coated with a polyethylene resin containing a magnesium compound.

In the present invention, the magnesium compound to be mixed with the polyethylene resin is, for example, magnesium hydroxide, magnesium carbonate, or magnesium oxide, and the magnesium compound to be mixed is 20 to 75% by weight, preferably 50% by weight.
It is preferred to use a polyethylene resin mixed with ~65% by weight. If the magnesium compound is less than 20% by weight, it will not be possible to sufficiently suppress protrusion and retraction, and if it is more than 75% by weight, the moldability of the cord will deteriorate, which is not preferable.

The protrusion and retraction behavior of plastic optical fiber barcodes is significantly different from that of copper wire coated with polyethylene; in the case of copper wire, only thermal expansion needs to be considered;
In the case of plastic optical fiber barcodes, the shrinkage of bare wires in response to heat and humidity is complex, and suppressing the protrusion and retraction of plastic optical fiber barcodes is a complex interaction between the shrinkage behavior and adhesive strength of the bare wires and the coating material. Therefore, it is surprising that a polyethylene resin containing a magnesium compound has such properties.

We also investigated the effects of magnesium compounds on the transmission loss and mechanical force of plastic optical fibers, but found that they had no effect at all. Furthermore, it has been found that the plastic optical fiber barcode of the present invention also exhibits a flame retardant effect. In particular, magnesium hydroxide is thought to have a very large flame retardant effect because it has a hydroxyl group.

This covering material is a non-halogen material that does not generate toxic gas when burned, but when a plastic optical fiber barcode is used in a humid atmosphere, the surface of the plastic optical fiber barcode is exposed to magnesium carbonate due to the influence of moisture and carbon dioxide gas. Changes to However, this has no effect on the physical properties, tensile strength, elongation, or cold resistance of the jacket material, and the flame retardant effect is sufficiently maintained. Furthermore, even when protruding and retracting, it is possible to maintain stable dimensional workability for long-term use and to maintain optical performance.

As for the particle size of the magnesium compound, it is preferable to use a small particle size from the viewpoints of uniform distribution with polyethylene, softening damage to the bare plastic optical fiber during molding, and maintaining optical performance.

Examples of polyethylene resins used as coating materials include soft low-density polyethylene, medium-density polyethylene, high-density polyethylene, and ethylene-vinyl acetate copolymer (
EVA), or ethylene-ethyl acrylate copolymer (EEA), water-crosslinkable polyethylene is used, preferably low density polyethylene, and EEA, EV
A is preferred.

These polyethylene resins have excellent performance such that the coating temperature for bare plastic optical fibers is 150° C. or less, there is no deterioration in optical performance, and the bare wires are not easily damaged.

(Example) In Examples, evaluation of optical performance, heat shrinkage and protrusion, and evaluation of dry-moist heat test were performed in the following manner.

The obtained plastic optical fiber barcode was measured at a wavelength of 570.650 nm using an Operex measuring machine with a parallel light beam obtained by a norogen lamp. Optical performance is calculated using the formula below.

Lo-Plastic optical fiber barcode 52mL -
Plastic optical fiber barcode 2m1, I□-light star (measured value) A 7-inch plastic optical fiber barcode 1'1m was accurately cut with a razor blade and placed in a fine oven at 95°C for 100 minutes. After standing for a period of time, the dimensions of the front covering material were measured after being allowed to cool for 15 minutes at room temperature. For protruding drawer 7, measure the dimensions of the covering material and then measure the protruding length with a 30x graduated looper.The retracting length is determined by cutting both end faces diagonally with a razor blade and retracting the plastic light into the covering material. Measure the bare fiber wire with a magnifying glass.

1 m of plastic optical fiber bar cord was accurately cut with a razor blade in a heat and humidity tester at 85°C, 95% R1+, 65°C, 95% RH humidity, and tested for 20 hours and 100 hours. After dispersion and cooling at room temperature for 15 minutes, the lengths of the plastic optical fiber barcode and the bare wire were measured using the heating dimension and protrusion/retraction measurement methods described above.

An example of a plastic optical fiber bar code with less protrusion and retraction coded with a polyethylene coating material containing a magnesium compound will be described below.

Example-1 Plastic optical fiber barcode with an outer diameter of 1.0 as a bare wire
A polyethylene system made by mixing EF1530 (Asahi Kasei Industries, Ltd.) polyethylene, 65% magnesium hydroxide containing at least 85% particle size of 1 micron or less, and 0.5% carbon by weight in the methyl methacrylate plastic optical fiber of the body. Outer diameter 2.2mm using 1 covering material
Obtained a plastic fiber optic barcode.

85゛C90% of this plastic optical fiber barcode
The deterioration performance after 1000 hours with R1+ is transmission loss of 570
88dB/km at nm, 150dB/la at 650nm
An excellent result of n was obtained. Moreover, the mechanical strength was 120% in elongation at break and 10.5 kg/cffl in breaking strength, so there were no problems.

95° of 1 m of the obtained plastic optical fiber barcode
The dimension after Cl2O time was 98.5 cm, and the protrusion retraction was ±0.0 rail. Also, the dimension after 100 hours is 97.5
At c+n, the protrusion retraction was -0.1 mm. Dimensions after 100 hours of moist heat test at 85°C and 95% R1 condition are 97
．． 7cm protrusion and retraction is -0.1mm and 65°C9
Good results were obtained with a dimension of 100.0 cm and a protrusion retraction of ±0.0 mm under 5% R1+ conditions for 100 hours.

The resulting plastic optical fiber barcode passed both the vertical and horizontal tests of the UI and flame retardant test VW-1.

Examples 2 and 3 Plastic optical fiber barcodes were obtained under the same conditions as in Example 1, except that polyethylene coating materials containing 40% by weight and 50% by weight of magnesium hydroxide were used.

Table 1 shows the results of the same test as in Example-1.

Comparative Example Using the same bare plastic optical fiber as in the example, the cylinder and die temperature of the 40 (Incorporated Foundation) extruder was set to 140.
A plastic optical fiber barcode was obtained using a polyethylene coating of M2270 (Asahi Kasei Kogyo Co., Ltd.) under the conditions of 'C.

Table 1 shows the results of the same test as in Example-1.

Note that in Table 1 and in Examples and Comparative Examples, the dirt floor indicates that the bare plastic optical fiber wire protrudes from the coated cord, and -nun indicates that the bare plastic optical fiber cord wire retracts from the coated cord. appear.

(Effects of the present invention) The plastic optical fiber barcode of the present invention can be used even under extreme thermal conditions and high temperatures compared to conventional ones.
The present invention provides a plastic optical fiber bar code with less protrusion and retraction, and is also useful as a flame retardant code.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the protrusion of the bare wires of the plastic optical fiber bar code, and FIG. 2 is a sectional view showing the retraction of the bare wires of the plastic optical fiber bar code. 1 Niblast optical fiber bare wire 2: Covering material Patent applicant Asahi Kasei Industries, Ltd. Figure 2

Claims (1)

[Claims] A plastic optical fiber cord consisting of a double core-sheath plastic optical fiber whose outside is coated with polyethylene resin containing a magnesium compound.