JPH0223307A - Plastic optical fiber cord - Google Patents

Abstract

PURPOSE:To prevent the migration of the plasticizer of a coating layer to the plastic optical fiber by constituting the coating layer of a specific vinyl chloride resin compsn. CONSTITUTION:The coating layer 2 is constituted of the vinyl chloride resin compsn. formed by compounding 30-100pts.wt. polyester plasticizer and 1-20 fire retardant with 100pts.wt. vinyl chloride polymer. The mol. wt. of the polyester plasticizer (polymer) is preferably 1,500-3,000 and the migration of the plasticizer from the vinyl chloride resin compsn. is liable to arise if the mol. wt. is smaller than 1,000. On the other hand, the mixing with the vinyl chloride polymer is difficult if the mol. wt. thereof exceeds 5,000. The migration of the plasticizer of the vinyl chloride resin compsn. of the coating layer 2 to the plastic optical fiber is prevented in this way.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a plastic optical fiber cord, and more specifically, a plastic optical fiber cord that does not cause migration of plasticizer to the optical fiber and has good flame retardant performance. Regarding.

[Prior Art] Generally, when plastic optical fiber cords are used for communication, signal transmission, etc., the surroundings of the optical fibers are coated with polyethylene or vinyl chloride resin to prevent damage to the optical fibers due to abrasion, lateral pressure, impact, etc. It is coated with a material such as resin and used in the form of a cord or cable. Attempts have been made to apply vinyl chloride resin compositions to applications that require flame retardancy, such as internal wiring of electronic devices. However, when using a widely used general vinyl chloride resin composition directly in the coating layer of an optical fiber, plasticizers (e.g., phthalate esters such as dioctyl phthalate, phosphate esters, etc. etc.) migrate to plastic optical fibers during the melt-extrusion coating process at high temperatures or during long-term use, leading to the problem of deteriorating the light transmittance of the optical fibers. Regarding flame retardant performance, there is also the problem that since the flammable plastic optical fiber occupies the center of the cord, it is not possible to achieve satisfactory flame retardant performance for a plastic optical fiber cord by coating it with a normal vinyl chloride resin composition. was there.

As a technique for preventing the migration of a plasticizer in a plastic optical fiber, Japanese Patent Application Laid-Open No. 59-34501 discloses the use of trimellitic acid ester as a plasticizer. Although it is true that the use of trimellitic acid ester as a plasticizer improves migration compared to the most widely used plasticizer, dioctyl phthalate, There is a problem in that migration prevention performance is not sufficient under harsh environments such as when left in the environment.

[Problems to be Solved by the Invention] As mentioned above, when trying to obtain a flame-retardant plastic optical fiber cord by using a vinyl chloride resin composition in the coating layer of a plastic optical fiber, it is necessary to use a plasticizer. Although there are drawbacks such as deterioration of light transmission performance due to migration to plastic optical fibers and problems of insufficient flame retardancy, the purpose of the present invention is to solve these problems and create a flame retardant fiber without the problem of plasticizer migration. The object of the present invention is to provide a plastic optical fiber cord with good properties.

[Means for Solving the Problems] An object of the present invention is to provide a plastic optical fiber cord consisting of a plastic optical fiber and a coating layer formed around the optical fiber, in which the coating layer is made of vinyl chloride polymer 100% by weight. This is achieved by using a plastic optical fiber cord made of a vinyl chloride resin composition containing: 30 to 100 parts by weight of a polyester plasticizer and 1 to 20 parts by weight of a flame retardant.

The present invention will be described in detail below with reference to the drawings.

As illustrated in FIGS. 1(a) to (e), the plastic optical fiber cord 3 of the present invention is composed of at least one plastic optical fiber 1 and a coating layer 2 formed around the optical fiber. It is something that FIG. 1(a) shows one plastic optical fiber covered with a coating layer 2, FIG. 1(b) shows one in which a coating layer 2 is formed around a pair (two) of plastic optical fibers 1, Figure 1 (C) ~
(e) shows three or more plastic optical fibers 1 in which coating layers 2 are formed in different shapes, and illustrates a typical cross-sectional form of the plastic optical fiber cord 3.

The plastic optical fiber used in the present invention includes:
There are polymethyl methacrylate optical fibers, polystyrene optical fibers, polycarbonate optical fibers, etc. Although there are no particular limitations, fibers with a core of polymethyl methacrylate, a fluorinated acrylate copolymer, a copolymer of tetrafluoroethylene and vinylidene fluoride, etc. A polymethyl methacrylate optical fiber having a cladding made of a transparent fluororesin such as a polymer is preferably used.

Further, the diameter of the optical fiber is preferably about 0.1 m to 1.5 m, but preferably 0.25 m to 1.0 m.

The coating layer 2 is composed of a vinyl chloride resin composition prepared by blending ■ 30 to 10 parts by weight of a polyester plasticizer and 1 to 20 parts by weight of a flame retardant to 100 parts by weight of a vinyl chloride polymer. It is necessary that the

As the vinyl chloride polymer, vinyl chloride homopolymers, copolymers with ethylene, copolymers with propylene, copolymers with vinyl acetate, copolymers with acrylic esters, etc. can be used. The degree of polymerization of vinyl chloride polymer is 500-3
000 is preferred.

Polyester plasticizers can be produced from dicarboxylic acids and aliphatic diols using conventional methods. Dicarboxylic acids include succinic acid, glutaric acid, adipic acid,
Azelaic acid, sebacic acid, etc. can be used alone or in a mixture, and adipic acid is particularly suitable. On the other hand, as the aliphatic diol, butanediol, hexanediol, bentanediol, propylene glycol, diethylene glycol, etc. can be used alone or as a mixture.

In addition, the molecular weight of the polyester plasticizer (polymer) is 10
00 to 5000 is used, and 1500 to 3000 is particularly preferred. If the molecular weight is less than i ooo, migration from the vinyl chloride resin composition will easily occur, while if it exceeds 5,000, it will be difficult to mix with the vinyl chloride polymer.

The blending ratio of the polyester plasticizer to the vinyl chloride resin composition needs to be 30 to 100 parts by weight based on 100 parts by weight of the vinyl chloride polymer. If the amount is less than 30 parts by weight, a sufficient plasticizing effect cannot be obtained and the flexibility is insufficient for use as a coating material for plastic optical fibers.

On the other hand, if it exceeds 100 parts by weight, the hardness as a coating material will be insufficient and the flame retardance will deteriorate, and in order to ensure flame retardancy, it will be necessary to add a large amount of flame retardant, which is not preferable.

As a flame retardant, tetrabromo bisphenol/L/ is commonly used to make vinyl chloride resin compositions flame retardant.
A. Bromine flame retardants such as decabromidiphenyl oxide, phosphorus flame retardants such as tricresyl phosphate and trisdichloropropyl phosphate, and inorganic flame retardants such as antimony trioxide, aluminum hydroxide, and magnesium hydroxide. Antimony trioxide is particularly preferred. The blending ratio of the flame retardant to the vinyl chloride resin composition is from 1 to 2 parts by weight per 100 parts by weight of the vinyl chloride polymer.
0 parts by weight are required, particularly 2 to 10 parts by weight are preferred. If it is less than 1 part by weight, the flame retardant performance is insufficient;
If the amount exceeds 1 part by weight, the mechanical properties of the vinyl chloride resin composition will deteriorate, such as the tensile strength of the vinyl chloride resin composition will decrease.

In addition to the above-mentioned components, the vinyl chloride resin composition may contain additives such as stabilizers, lubricants, fillers, pigments, etc. that are commonly used in soft vinyl chloride resin compositions, if necessary.

Typical examples of the shape of the plastic optical fiber cord of the present invention are shown in FIGS. 1(a) to 1(e), but these are merely illustrative, and any necessary shape can be adopted depending on the application. However, in order to obtain good flame retardant performance, in the cross section of the plastic optical fiber cord, the cross-sectional area (A) of the plastic optical fiber and the cross-sectional area (B> of the coating layer made of the vinyl chloride resin composition) must be such that B/ It is preferable to satisfy A≧2, and it is particularly preferable that B/A≧3.When B/A<2, the proportion of flammable plastic optical fiber in the plastic optical fiber cord increases, so that sufficient flame retardance is not achieved. performance may not be achieved.

The thickness of the coating layer may be determined depending on the application, but in order to ensure the original purpose of the coating layer, which is to protect the plastic optical fiber, and to ensure flame retardancy, the thickness of the coating layer is preferably 0.3 or more, especially 0.3 mm or more. 5# or more is preferable.

The plastic optical fiber cord of the present invention can be manufactured, for example, by using an apparatus as shown in FIG. The plastic optical fiber 1 is unwound from the bobbin 7 and supplied to the crosshead 5 of the extrusion @ 4, where it is melt-coated with a vinyl chloride resin composition mixed with a polyester plasticizer and a flame retardant in advance, and cooled with a cooling water layer 6. By winding the plastic optical fiber cord 3 onto the bobbin 8, 1q of plastic optical fiber cords 3 can be obtained.

The present invention will be described in detail in Examples below, and the test methods used in the Examples are as follows.

Flame retardancy test> As shown in Figure 3, a plastic optical fiber cord 3 as a sample is attached vertically, and the flame of a Tyrol gas burner 9 (inner flame temperature 836°C or higher) is set at an inclination angle of 20 degrees. The tip 11 of the burner is placed on the surface of the sample as shown in Figure 3, and the burner flame is applied to the sample for 15 seconds to measure the burning duration of the sample.The shorter the burning duration, the more flame retardant. If the burning duration is 60 seconds or more, it is determined that the flame retardance is poor.If the absorbent cotton 10 placed under the sample burns due to the burning sample falling, it is determined that the flame retardance is poor. judge.

Heat and humidity resistance test〉 A 30 m long sample was placed in a treatment tank at 70°C and 90% relative humidity and treated for 1000 hours, and the light intensity retention rate defined by the following formula was used to evaluate the deterioration of translucency due to plasticizer migration. Determine the degree. It is determined that the smaller the light amount retention rate, the greater the degree of deterioration due to migration.

However, a 660 nm LED is used as the light source, and the amount of transmitted light is measured with a power meter.

[Example] Example 1 A plastic optical fiber with an outer diameter of 1 m using polymethyl methacrylate resin for the core and fluorinated acrylate resin for the cladding was prepared using: ■ 100 parts by weight of vinyl chloride polymer with a degree of polymerization of 1300. ■Polyester plasticizer (PN
-280, Adeka Argus) 50 parts by weight■ A polyvinyl chloride resin composition with a JIS hardness of 89 (measurement method JIS-7201) containing 25 parts of Andemo trioxide as a flame retardant, as shown in Figure 2. Coating was carried out using the apparatus shown in Figure 2 under the conditions of melt coating temperature of 165°C and processing speed of 30 TrL/min.
) plastic optical fiber cord was obtained.

Flame retardancy test of the obtained optical fiber cord (number of samples: 5)
As a result, all samples had a combustion duration of 0 seconds, and exhibited excellent flame retardant performance with no burning of absorbent cotton.

In addition, the heat and humidity resistance test was also excellent, with a light intensity retention rate of 76%, with no deterioration in light transmittance due to plasticizer migration, except for a decrease in the amount of transmitted light due to moisture absorption.

Comparative Example 1 A plastic optical fiber cord was obtained under the same conditions as in Example 1, except that antimony trioxide, which is a flame retardant, was not blended. When this plastic optical fiber cord was subjected to a flame retardancy test, three out of five samples had a combustion duration exceeding 60 seconds, and the flame retardance was poor.

Comparative Example 2 Same as Example 1 except that a polyvinyl chloride resin composition was used, in which 50 parts by weight of trioctyl trimellitate and 5 parts by weight of antimony trioxide were blended with 100 parts by weight of vinyl chloride polymer with a degree of polymerization of 1300. A plastic optical fiber cord was obtained under the same conditions. Although the flame retardancy test result of this plastic optical fiber cord was good, the heat and humidity resistance test result showed that the amount of transmitted light decreased significantly after 630 hours of processing time, and the light amount retention rate became 20%.

[Effects of the Invention] As explained above, the plastic optical fiber cord of the present invention does not have the problem that the plasticizer in the vinyl chloride resin composition of the coating layer migrates to the plastic optical fiber.
Since the light transmittance does not deteriorate even when used under harsh conditions for a long period of time and it has good flame retardant performance, it has the effect of greatly expanding the range of application of plastic optical fiber cords.

[Brief explanation of the drawing]

FIG. 1 (a> to e) is a cross-sectional view showing a typical example of an embodiment of the plastic optical fiber cord of the present invention, and FIG. 2 is a schematic configuration showing an example of an apparatus for manufacturing the cord of the present invention. Figure 3 is a side view of a sample and test apparatus showing the method of flame retardancy testing. 1...Plastic optical fiber 2
.........Coating layer 3...Plastic optical fiber cord 4...Extruder 5...・・・・・・・・・Cross head be ζ I hemato

Claims (1)

[Claims] 1. In a plastic optical fiber cord consisting of a plastic optical fiber and a coating layer formed around the optical fiber, the coating layer is composed of (1) 100 parts by weight of vinyl chloride polymer, (2) polyester plastic 3. A plastic optical fiber cord comprising a vinyl chloride resin composition containing 30 to 100 parts by weight of a flame retardant (3) and 1 to 20 parts by weight of a flame retardant.