JPS60222803A - Light transmitting plastic fiber - Google Patents

Abstract

PURPOSE:To enhance UV ray resistance of a light-transmitting synthetic resin fiber using the polymer essentially consisting of methyl methacrylate units as a core material, by incorporating a specified benzotriazole compd. as a core component and/or a sheath component. CONSTITUTION:The intended light-transmitting plastic fiber is obtained by incorporating the benzotriazole compd. represented by the formula (R1 is H or halogen; R2 is H or 1-8C alkyl; and R3 is 1-8C alkyl) in an amt. of 1-500ppm in the core component essentially consisting of methyl methacrylate units and/or the sheath component made of fluororesin or the like. The benzotriazole compd. represented by the formula is embodied by N(2'-hydroxy-5'-methyphenyl)-benzotriazole, and N(2'-hydroxy-3',5'-ditertiarybutylphenyl)-benzotriazole, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic optical transmission fiber having a core-sheath structure and having excellent UV resistance.

Optical transmission fibers have traditionally been manufactured using glass-based materials as a base material, and are used as optical signal transmission media for measurement control between devices and within devices.
It is widely used for data transmission, medical purposes, decoration, and image transmission. However, optical transmission fibers based on glass-based materials have the disadvantage of poor flexibility unless the fibers are made with a thin inner diameter, are easily broken, have a high specific gravity, and are expensive, including connectors. For these reasons, various attempts have been recently made to make them from plastic.

The major characteristics of using plastic are that it is lightweight, and even fibers with a thick inner diameter are strong and flexible.Therefore, high apertures and large diameters are possible, and it is easy to combine with light receiving and emitting elements. It has excellent operability. A general method of manufacturing such a light transmission edge a using plastic is to use a plastic with a large refractive index and good light transmission as a core component, and a plastic with a smaller refractive index and transparent material as a core component. A fiber having a single core-sheath structure is formed by using plastic as the sheath component. This method transmits light by reflecting it at the core-sheath interface, and the greater the difference in refractive index between the plastics that make up the core and sheath, the better the light transmission properties.

As a plastic with high light transmittance, an amorphous material is preferable, and polymethyl methacrylate and polystyrene are attracting attention industrially (for example,
-8978 Publication).

However, in such plastic optical transmission fibers, the transmission loss decreases due to ultraviolet rays, and the decrease value is large.
As an optical signal medium, it sometimes lacked reliability. Also,
It has a drawback in heat resistance, and when it is applied to moving objects such as automobiles, ships, aircraft, and robots, there are restrictions on the uses and places where it can be applied.

The inventors of the present invention have grappled with the current situation, and as a result of intensive study on the development of a plastic optical transmission fiber with excellent ultraviolet resistance, they have arrived at an uninvented invention. That is, the present invention provides a plastic optical transmission fiber having a core-sheath structure having a core component of a polymer mainly composed of methyl methacrylate, which has the general formula (A): (where R1 is hydrogen and halogen is , R2 is hydrogen or an alkyl group having 1 to 8 carbon atoms, and R2 is an alkyl group having 1 to 8 carbon atoms. The purpose of the present invention is to provide a plastic optical transmission fiber having excellent ultraviolet resistance, characterized in that the core component and/or sheath component are polymers containing 1 to 500 PPm of the compound.

In the temperature range from room temperature to around 80°C, the plastic optical transmission fiber of the present invention has a lower rate of deterioration in light guiding performance due to exposure to ultraviolet rays than conventionally proposed optical transmission fibers. This can significantly improve reliability as a signal transmission medium. Furthermore, unexpectedly, the plastic optical transmission fiber shows almost no deterioration in light guiding performance even at temperatures at which the previously proposed optical transmission fibers mentioned above cannot be used, and has no practical problems in terms of flexibility. It is.

The polymer mainly composed of methyl methacrylate used as the core component in the present invention is a homopolymer or a copolymer of methyl methacrylate containing at least 60% by weight of repeating units of methyl methacrylate, and includes ethyl methacrylate, ethyl methacrylate,
Propyl methacrylate, butyl methacrylate, isobutyl methacrylate, and cyclohexyl methacrylate are copolymers having a methacrylic ester with an 8818 type hydrocarbon group having 8 to 20 carbon atoms in the ester moiety, and copolymers containing these and 10% by weight. - The following copolymers such as methyl acrylate, ethyl acrylate, and 2-ethylhexyl acrylate are useful. Among these, a copolymer containing 70% or more of methyl methacrylate units is particularly preferred as a core component because it is highly pure, extremely transparent, and easily available. The proportion of the methacrylic acid ester component having 8 or more alicyclic hydrocarbon groups is 8 to 40% by weight based on the entire core component polymer. When it is less than 3%, the flexibility is excellent, but the contribution of the core component itself to improving heat resistance is small; on the other hand, when it exceeds 40%, the heat resistance is excellent, but
Practically speaking, the flexibility is insufficient and undesirable.

Among these methacrylic acid esters, particularly preferred are 1-adamantyl methacrylate, 2-adamantyl methacrylate, 8,5-dimethyl-1-adamantyl methacrylate, fornyl methacrylate, and isoI methacrylate.
Shiginru, methacrylic acid-p-menthane, methacrylic acid 2
-Methyl camphan, methacrylic acid, l-menthyl methacrylate, methacrylic acid 2.2.5-
Trimethylcyclohexane can also be obtained.

On the other hand, as the sheath component, which is another important element constituting the present invention, a transparent resin or fluorine comb having a refractive index at least 8 increments smaller than that of the core component is used. If the difference in the refraction chamber is smaller than 8%, the proportion of light reflected by the sheath component decreases by 1/2, and the light guide loss increases. Specifically, the refractive index is preferably 1643 or less, and the polymer is desirably a non-crystalline, nearly amorphous polymer, and has good adhesion to the buckwheat component.

Preferred transparent resins include fluororesins and thermoplastic fluorocombs. Examples of the fluororesin include vinyl fluoride, vinyl fluoride, trifluoroethylene, tetrafluoroethylene, hexafluoropropene, trifluoromethyl trifluorovinyl ether, perfluoropropyl trifluorovinyl ether.
Teroloethyl, l,1,1,8.8,8-hexafluoro-2-propyl methacrylate, 1,t-diethyl-2.2,8.4,4,4-hexafluoro-1 methacrylate
-butyl, 1-propyl methacrylate-2.2,8,4
, 4.4-hexafluoro-1-butyl, methacrylic acid l.

■-Dimethyl-8-trifluoromethyl-2.

2,4,4.4-pentafluorobutyl acrylic acid 2-)
Lifluoromethyl-2.8,8,8-tetrafluoropropyl, 2,2,8.8-tetrafluoropropyl methacrylate 1,1-dimethyl-2.2.8.8
- Tetrafluoropropyl, MEC 1-norate-2-trifluoromethyl-8.8.8-trifluoropropyl or MEC 1-norate-2-trifluoroisopropyl, etc. I can do it.

Preferred fluororubbers include vinylidene fluoride-hexafluoropropene copolymer, hnylidene fluoride-pentafluoropropene copolymer, and hnylidene fluoride-chlorotrifluoroethylene copolymer. be able to. This is suitable for winter C. It is a vinylidene fluoride-hexafluoropropene copolymer.

The ratio of core component to sheath component is approximately 70 = 30 to 98 by weight.
:2, preferably about 80:20 to 95:5 for one year old. In addition, the outer diameter of the optical transmission fiber having a core-sheath structure is about 0.15 to 1.5 g, and the outer diameter of the optical transmission fiber is about 0.20 to 1.5 g.
．． It is 018.

The most important elements constituting the present invention are the general formula (A):
The core component and/or T It is to be made into a pod component.

Specific examples of the benzotriacyl compound represented by the general formula (A) include 2(2'- and droxy-5'-methylphenyl)-benzotriazole, 2(2-hydroxy-8,-5 -ditert-butylphenyl)-benzotriazole, 2-(2'-hydroxy-8', 5
'-ditert-amyl-phenyl)-benzotriazole, 2(2-hydroxy-5'-octylphenyl)-benzotriazole, 2(2-hydroxy-8,5
-ditert-butylphenyl)-5-chloro-benzotriazole, 2-(2-hydroxy-8-tert-butyl-5-methylphenyl)-5-chloro-benzotriazole, and the like. The amount of the benzotriazole compound represented by the general formula (A) to be added is 1 to a00 ppm based on the core component polymer. Particularly acidic is Al at kO~150PPm. If it is less than tppm, the ultraviolet resistance will not be sufficient, and if it is more than ao o ppm, there will be drawbacks such as a decrease in optical transmission performance.

The method of adding the benzotriazole compound represented by the above general formula (A) is not particularly limited, but it is necessary to add it so that it is uniformly dispersed in the core component polymer.

Generally, techniques for adding stabilizers such as ultraviolet absorbers to plastics are known. However, when a polymer containing a stabilizer other than the benzotriazole compound represented by the general formula (A) of the present invention is used as the core component and/or sheath component, the core component and sheath fraction polymer This results in disadvantages such as coloring, the ultraviolet absorption of the stabilizer extending into the visible region, and the light transmission performance being severely impaired, making it unusable as a plastic transmission fiber.

As the method for polymerizing the core component of the present invention, conventionally known methods such as suspension polymerization, bulk polymerization, etc. can be employed. However, in the suspension polymerization method, a large amount of water is used, so
Foreign matter contained therein will not mix into the polymer, and
Since there is a possibility that foreign substances may be mixed in during the dehydration process, if necessary, foreign substances such as dust are removed by filtration or distillation before polymerization. A more desirable method is to first produce the core component polymer in two steps: a slow bulk polymerization step at high temperature, followed by a continuous separation step of volatile components mainly containing residual unreacted monomers; Furthermore, there is a method in which the manufacturing step of the core component polymer and the manufacturing step of the optical transmission fiber are performed in a continuous process. It is also desirable to carry out bulk polymerization of the core component, and then form the core component and sheath component from the resulting monopolymer by double extrusion.

The radical polymerization initiators used in each of the above polymerization methods include, for example, 2,2'-azobis(isobutyronitrile), 1,1-azobis(cyclohexanecarbonitrile), 2,2-7zobis(2,4 -dimethylvaleronitrile), azobisisobutanol diacetate, azo-tert-butane and other azo compounds;
t-butyl peroxide, dicumyl peroxide,
Examples include organic peroxides such as methyl ethyl ketone peroxide, di-tert-butyl perphthalate, di-tert-butyl peracetate, and di-tert-amyl peroxide.

The addition ratio of these polymerization initiators is 0.0 to the monomer.
Preferably it is 0.01 to 1 mole axe.

In addition, in the polymerization system, tert-methyl, n-methyl, I)-octyl, n-dodecyl mercaptan, etc. are added as chain transfer agents to control the molecular weight, about 1 molar or less based on the monomer. be done.

On the other hand, the sheath component polymer can be produced by conventionally known methods. In the case of the sheath component polymer, in the case of the core component polymer, the manufacturing method has no effect on optical transmission properties, so make sure that foreign substances such as dust do not get mixed in, and if necessary, use filtration methods etc. Due to garbage etc.
It is best to remove foreign substances and manufacture the sheath component polymer.

As described above, the present invention uses a core component containing a specific triazole compound and a polymer in a plastic optical transmission lIA1m having a core-sheath structure, so that the optical transmission performance is not impaired. Moreover, it is possible to provide a plastic optical transmission fiber with significantly improved UV resistance.

Furthermore, by using a specific monomer, the applicable temperature range can be greatly expanded, and its industrial value is extremely high.

Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

The light guide loss in the examples was measured using a 65Q diffraction grating spectrometer with a tungsten halogen lamp as the light source.
The output intensities of the optical transmission fiber to be measured and the reference optical transmission fiber at a wavelength of nm are read with a silicon photodiode, and the light intensity at the entrance and exit of the optical transmission fibers with different fiber lengths L (Ax) is calculated using the following formula. Measured as IO, I, and the light guiding loss α is me.

This formula shows that the smaller the α value, the better the optical transmission performance.

The UV resistance test was performed by comparing the light guide loss at the initial stage of irradiation and after irradiation using Sunshine Weathermeter (electrode: carbon).

The symbol "Chi" in the examples indicates weight superiority.

Example 1 25% bornyl methacrylate, 72% methyl methacrylate purified by vacuum distillation.

80% methyl acrylate to 00% n-dodecyl mercaptan
0.10% of 25th,2,2-azohis(2°4-dimethylvaleronitrile) and 300 ppmi of 2(2-hydroxy-5-methylphenyl)benzotriazole were added to the monomer mixture in the absence of oxygen. Mix and heat to 150℃
The mixture was maintained at a constant temperature and sent to the f co-reaction tank, where it was prepolymerized for a residence time of 8 hours. Next, the temperature was maintained at 220°C, and the polymerization was completed with a residence time of 2 hours, and the temperature was maintained at 25°C.
, the limiting viscosity [η: lO, 90
, a polymer with a refractive index of 1.49 was obtained. Furthermore, this polymer is
Heat it to 55°C and feed it to a two-stage vented extruder.
1 diameter from the center of a double extrusion nozzle maintained at 85°C
While discharging the core component of the strand-like polymer, 2-trifluoromethyl-8 methacrylate was added to it.
,8,8-trifluoropropyl-acrylic 2 (wt%
) (contains 150 ppm of 2(2'-hydroxy-5-methylphenyl)benzotriazole), refractive index 1.89
, melt viscosity 2×10 Bois (220° C.)] to obtain a strand with a core-sheath structure. The blending ratio of the core-sheath polymer was set at 90:10.

When the light guide loss was measured, it was 190 peaks B/- at a wavelength of 650 nnu. This plastic optical transmission fiber was used for 600 hours at Sunshine Weathermeter.
Measurement of exposure light guide loss 47t Kokoro 2 1 0 drv
Im here.

Examples 2 to 5 Plastic optical transmission fibers (0.85 to 0.75
aφ) was obtained.

Table 1 shows the results of measuring the light guide loss, ultraviolet resistance, and heat resistance of the obtained gamma fibers.

As shown in Table 1, all of the plastic optical transmission fibers had excellent properties.

Comparative Example 1 In Examples 1 and 2, plastic optical transmission fibers containing no benzotriazole compound yzl represented by the general formula (A) were tested with a sunshine weather meter at 60°C.
After being exposed for 0 hours, the light guide loss was measured and all values were over 1000 dB/m, and the UV resistance was significantly poor.

Claims (4)

[Claims] (1) In a plastic optical transmission fiber having a core-sheath structure whose core component is a polymer mainly composed of methyl methacrylate, general formula (A): 3 (where R1 is hydrogen, one is halogen, 2 is hydrogen or 1 is an alkyl group having 1 to 8 carbon atoms, R3 is 1 to 8 carbon atoms
8 alkyl groups) at least one compound selected from the group of benzotriazole compounds represented by
A plastic optical transmission fiber having excellent ultraviolet resistance, characterized in that the core component and/or sheath component are a polymer containing ~500 pp+u. (2) Benzotriazolenyl)-benzotriazole, 2(2-hydroxy-8,
5-ditertiary-butylphenyl)-benzotriazole, 2-(2-hydroxy-5-octylphenyl)-benzotriazole, 2(2-hydroxy-8,5
-ditert-butylphenyl-5-chloro-benzotriazole, 2'-hydroxy-8-tert-butyl-5-methylphenyl)-5-chloro-benzotriazole. Optical transmission fiber. (3) A polymer mainly composed of methyl methacrylate contains 8 to 40% by weight of a methacrylic ester having an alicyclic hydrocarbon group having 8 to 20 carbon atoms in the ester moiety. The plastic optical transmission Al fiber according to claim 1, which is a composite. (4) Methacrylic acid esters having an alicyclic hydrocarbon group having 8 to 20 carbon atoms in the ester moiety include fornyl methacrylate, fentyl methacrylate, and l-methacrylate.
The plastic optical transmission fiber according to claim 3, which is menthyl, adamantyl methacrylate, or dimethyladamantyl methacrylate.