JPH0777642A - Flame-retardant plastic optical fiber cable - Google Patents

Abstract

PURPOSE:To enable the application of the plastic optical fiber to even such a field where high heat resistance, flame retardance and tensile strength are simultaneously needed. CONSTITUTION:This flame-retardant plastic optical fiber cable has a first coating layer consisting of a fluorine-contained polyolefin resin compsn. which consists of a resin compsn. contg. at least fluorine atoms and has >=59wt.% ratio of the fluorine atoms or other halogen atoms included in this resin compsn. and a second coating layer consisting of a polyamide resin on the outer side of a plastic optical fiber consisting of a core and a sheath.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic optical fiber cable having excellent heat resistance, flame retardancy, oil resistance and chemical resistance, which is used for FA, automobiles, etc. as a short-distance optical transmission medium. Is.

[0002]

2. Description of the Related Art Plastic optical fibers are more flexible than silica-based fibers, have a large diameter and a high numerical aperture, and are easy to process and connect to end faces. The application to the field of sensors and sensors has begun. In the plastic optical fiber that has been put into practical use, a resin mainly composed of methyl methacrylate or a polycarbonate resin is used for the core material, and a vinylidene fluoride copolymer or a fluorinated methacrylate copolymer is used for the sheath material. There is something. It is also used as a plastic optical fiber cable in which the outside of the sheath is coated with low density polyethylene or polyvinyl chloride.

[0003]

The flame-retardant plastic optical fiber cables coated with polyvinyl chloride or flame-retardant polyethylene, which have hitherto been put into practical use, have a heat resistance temperature of at most 85 ° C. and a tensile strength. Since it is not so strong, the places where it can be applied are limited in applications such as automobiles that require high heat resistance and tensile strength.

Further, when making a polyamide resin flame-retardant,
Usually, 6 to 8% of melamine cyanurate is added. However, when this flame-retardant polyamide resin is used for coating a plastic optical fiber cable, it is not practical because the cable surface becomes rough and the sheath layer is colored to greatly increase the transmission loss.

[0005]

DISCLOSURE OF THE INVENTION In order to provide a flame-retardant plastic optical fiber cable having a higher heat-resistant temperature and being flame-retardant, the present inventors have earnestly studied about the material of the covering material and the cable structure. As a result, the present invention has been reached. According to the present invention, a resin composition containing at least a fluorine atom is provided outside a plastic optical fiber element consisting of a core and a sheath, and the proportion of fluorine atoms or other halogen atoms contained in the resin composition is 59. The present invention relates to a flame-retardant plastic optical fiber cable, which has a first coating layer made of a fluorine-containing polyolefin resin composition whose content is at least wt% and a second coating layer made of a polyamide resin. With such a cable structure,
A flame-retardant plastic optical fiber cable that passed the flame-retardant standard was obtained without flame-retarding by adding melamine cyanurate to the polyamide resin.

The flame-retardant plastic optical fiber cable of the present invention will be described in detail below. In the present invention, known resin compositions can be used as the resin composition constituting the core. For example, a methyl methacrylate homopolymer or a copolymer containing 50% by weight or more of methyl methacrylate,
As the copolymerizable component, acrylic acid esters such as methyl acrylate, ethyl acrylate, and n-butyl acrylate, ethyl methacrylate, propyl methacrylate,
There are methacrylic acid esters such as cyclohexyl methacrylate, maleimides, acrylic acid, methacrylic acid, maleic anhydride, styrene and the like, and one or more of them can be appropriately selected and copolymerized.

Further, as the resin composition constituting the sheath,
Known products such as a fluorinated methacrylate copolymer and a vinylidene fluoride copolymer can be used. These sheath materials are coated to a thickness of 2/1000 to 300/1000 of the core diameter to form a plastic optical fiber strand. The manufacturing method is a clean environment with little dust and
Using a special nozzle and two extruders, a core material and a sheath material in a molten state are molded into an optical fiber having a two-layer structure of core-sheath by a composite spinning method. And 1.3 times-3.
Stretching to 0 times to orient the molecules to improve the mechanical properties and obtain a plastic optical fiber strand. The plastic optical fiber element wire thus produced is coated with a specific resin composition to further improve heat resistance and mechanical properties, and is actually used as a plastic optical fiber cable.

When the temperature is higher than 100 ° C., the glass transition point of the resin composition mainly containing methyl methacrylate as the core material is approached, so that the molecular orientation is taken and the plastic optical fiber strand is largely heat-contracted. For this reason, the transmission loss increases sharply or is largely retracted from the coating layer, so that the coupling efficiency with the light source or the photodetector is significantly reduced. In order to prevent this, it is conceivable to coat the outside of the sheath layer with a specific coating resin composition, but as a result of diligent studies, in order to prevent thermal shrinkage of the plastic optical fiber strand at high temperature, plastic It has been found that it is effective to coat the optical fiber element wire with a resin that is hard and has excellent dimensional stability so that the orientation is hardly applied (the primary coating method described later). Further, in order to obtain a plastic optical fiber cable having excellent flame resistance and heat resistance, a fluorine-containing polyolefin resin having a content of fluorine atoms or other halogen atoms of 59% by weight or more is used as the first coating layer, It was found that a plastic optical fiber cable having a multi-layer structure, which has a coating layer made of polyamide resin around it, should be used.

Examples of such a fluorine-containing polyolefin resin include polyvinylidene fluoride, a vinylidene fluoride-chlorotrifluoroethylene random copolymer grafted with fucca vinylidene, and vinylidene fluoride-tetrafluoroethylene copolymerization. Coalescence, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoro Ethylene-perfluoroalkyl vinyl ether copolymer, vinylidene fluoride-
Chlorotrifluoroethylene copolymer, ethylene-chlorotrifluoroethylene copolymer, chlorotrifluoroethylene polymer, further, a mixture of the above fluorine-containing polyolefin resins, vinylidene fluoride resin and methyl methacrylate resin A mixture, a mixture of a vinylidene fluoride resin and a known fluororesin, a mixture of a fluorine-containing polyolefin resin and an olefin resin, and other known fluorine-containing polyolefin resins and a mixture of these and other resins can be used. Among these, it is preferable to use a resin composition containing a vinylidene fluoride structural unit, such as a vinylidene fluoride-based copolymer or a mixture of polyvinylidene fluoride and another fluororesin. The resin composition containing a vinylidene fluoride structural unit can be coated at a relatively low temperature among the fluorine-containing polyolefin resin compositions, while it has strong adhesion to the sheath material, and also has sufficient hardness, mechanical properties, and flame retardancy. Since it has chemical resistance, it is preferably used as a covering material. However, Shore D of these fluorine-containing polyolefin resin compositions at 23 ° C.
The hardness value is 60 or more, and the tensile elongation at break is 20.
It is preferably 0% or more. Here, the Shore D hardness is a value measured by ASTM D2240 at 23 ° C, and the tensile elongation at break is 23 ° C and the ASTM
D1708, the value measured at a pulling speed of 100 mm / min. If the Shore D hardness value is too small, the plastic optical fiber cable is easily deformed by a load or tension at high temperature, and the transmission loss greatly increases, which is not preferable. In addition, the plastic optical fiber strand cannot withstand the force of shrinking at high temperature, the coating layer also shrinks, and the plastic optical fiber strand is greatly retracted from the end surface of the coating layer, causing a light source or light detection. The efficiency of coupling with the vessel becomes smaller. Further, if the breaking elongation is small, the plastic optical fiber cable is likely to be broken by pulling, bending or twisting, which is also undesirable. In a resin composition containing a vinylidene fluoride structural unit, the higher the content of the vinylidene fluoride structural unit, the higher the hardness,
The tensile strength increases, but the tensile elongation at break decreases. The tensile elongation at break is preferably 200% or more, more preferably 300% or more.

The periphery coated with this fluorine-containing polyolefin resin composition is further coated with a polyamide resin,
The flame-retardant plastic optical fiber cable of the present invention is obtained.
Polyamide resin usable in the present invention includes nylon 6,
Examples include nylon 66, nylon 11, nylon 12, nylon 610, nylon 612, amorphous nylon, and nylon-based thermoplastic elastomer. Among these, it is preferable to use nylon 11 and nylon 12. Nylon 11 and nylon 12 can be coated at a relatively low temperature among polyamide resins, but have strong adhesion to the sheath material, and have sufficient hardness, mechanical properties, and chemical resistance. In addition, since it has low hygroscopicity and a small dimensional change due to moisture absorption, it is preferably used as a covering material for plastic optical fiber cables.

As a method of coating a plastic optical fiber elemental wire with these resin compositions, a method of producing a plastic optical fiber elemental wire by a composite spinning method and then coating a heat-melted coating material on the outside thereof is used. It is preferable to take. The primary coating method is to coat a plastic optical fiber strand drawn by 1.5 to 3 times with a molten resin by using a crosshead die so as to coat a wire. At this time, it is unavoidable that the fiber is slightly stretched, but the fiber is not greatly stretched. In the cable manufactured by this method, the sheath and the primary coating are partially adhered to each other, but the fusion between the sheath and the primary coating is not complete, so that the sheath and the primary coating retain the degree of freedom of displacement. Therefore, the coating layer having excellent heat resistance has almost no orientation.
Even when exposed to a high temperature of 00 ° C or higher, the heat shrinkage of the coating layer is small. Therefore, the cable manufactured by such a method has excellent characteristics that heat shrinkage is small and light loss due to bending is small.

Further, the thickness of the coating layer may be appropriately determined according to the situation of actual use. Since the adhesion between the primary coating and the plastic optical fiber strand is quite strong, the fiber may stretch or be damaged if it is forcibly peeled off. It is appropriate to process. Therefore, it is necessary to make the thickness of the primary coating as thin as possible while taking flame retardancy into consideration, so that the ferrule size does not change from a general-purpose one to a large one. From this point of view, the thickness of the primary coating is most preferably about 0.01 to 0.05 mm. However, if the thickness of the coating layer is too small,
It does not exhibit sufficient mechanical properties even at room temperature, and at high temperatures of 100 ° C or higher, it cannot prevent shrinkage of plastic optical fiber strands and withdrawal from the coating layer, as well as durability against bending and twisting, ambient heat and chemicals. Is insufficient. On the other hand, if the thickness is too large, the heat from the resin composition for coating melted at a high temperature causes the plastic optical fiber element wire to be greatly damaged, resulting in a large increase in transmission loss. The preferable thickness of the first coating layer is 0.01 mm or more, more preferably 0.02 mm to 0.2 mm, and the total thickness of the plastic optical fiber cable having a multilayer structure is 0.2 m.
It is desirable to have a coating layer of m or more.

It is also possible to stack several coating layers on the outside of the coating layer made of polyamide resin. In this case, known resin compositions can be used in addition to the above-mentioned fluorine-containing polyolefin resin and polyamide resin. For example, polyethylene, polypropylene, ethylene-vinyl alcohol copolymer, thermoplastic elastomer, polyvinyl chloride, crosslinked polyolefin, crosslinked polyvinyl chloride, chlorinated polyethylene compound, polyester resin, polyurethane resin, silicone resin, thermosetting resin, ultraviolet light A curable resin or the like. Further, as the reinforcing fiber, aramid fiber, polyacetal fiber, ultra high molecular weight polyethylene fiber, metal fiber or the like may be interposed.

[0014]

〔Measuring method〕

-Shore D hardness-performed according to the method of ASTM D2240.

Tensile breaking strength-performed according to the method of ASTM D1708. Temperature 23 ℃, pulling speed: 100 mm
/ Min ・ Measured by cutback method with transmission loss of -52m-2m. Uses monochromatic light with a wavelength of 650 nm for the light source. Incident aperture angle 0.1
5 radians. -Combustion test-performed according to the method of UL standard VW-1.

Length retention rate-Cut the plastic optical fiber cable to a length of 1 m and put it in a constant temperature and humidity chamber under predetermined conditions.
Measure the length after leaving it for 000 hours, and measure 1m of the original length.
The length retention rate is calculated by the ratio with. -Projection and retraction of the end face-Cut the plastic optical fiber cable to a length of 1 m and put 100 in a constant temperature and humidity chamber under specified conditions.
After standing for 0 hour, the difference in position between the end surface of the coating layer and the end surface of the plastic optical fiber element wire is measured.

[0017]

[Example 1] As a plastic optical fiber strand, Luminus (trademark) FB- with a diameter of 0.95 mm manufactured by Asahi Kasei Corporation
950 was used. As a fluorine-containing polyolefin resin used for coating, vinylidene fluoride resin "KYNAR"
(Trademark) 740 "(manufactured by Elf Atochem Co.) and soft fluororesin" Sefraralsoft (trademark) G150 "(manufactured by Central Glass) are made, and Shore D hardness at 23 ° C is 74, and tensile rupture elongation at 23 ° C. The one having a degree of 400% was used.

A plastic optical fiber strand FB-950 was introduced into a die directly connected to the melt extruder, and the above-mentioned fluorine-containing polyolefin resin was coated to a thickness of 25 μm, and a plastic optical fiber cable with a diameter of 1.00 mm was provided. Was produced. Further, this plastic optical fiber cable was introduced into a die directly connected to the melt extruder in the same manner as above, and nylon 12 resin “Ube nylon 301
4B "(manufactured by Ube Industries, Ltd.) with a thickness of 0.6 mm to obtain a plastic optical fiber cable of the present invention having a diameter of 2.2 mm.

The transmission loss at an optical wavelength of 650 nm of this plastic optical fiber cable was measured by using a fiber loss spectroscope FP-889 (manufactured by Operex).
When measured by the cutback method of 52 m-2 m, 13
It was 0 dB / km, and there was almost no increase in loss due to cable formation. This plastic optical fiber cable was left for 1000 hours in a constant temperature oven having a dry heat of 105 ° C., and a change in transmission loss at an optical wavelength of 650 nm was measured. What was 130 dB / km at the time of manufacture was 175 dB / km even after being left for 1000 hours, and the increase in loss was small.
In addition, the length retention rate is 99.6%, which is almost non-shrinking, the end face of the plastic optical fiber wire is hardly retracted from the coating layer by 0.1 mm, and the cable itself is not deformed. It showed heat resistance. In addition, the temperature of 85 ℃ and humidity of 95% RH
When left standing for 00 hours and similarly measured the change in transmission loss at an optical wavelength of 650 nm, it was 130 dB / k at the time of manufacture.
m was 170 dB / k even after 1000 hours
m, and the moisture and heat resistance is also excellent.

Next, a tensile test was conducted on this plastic optical fiber cable. The tensile tester "SHIN
Using KOH model TOM-500 ", ASTM
Using the method according to D638, temperature 23 ℃, pulling speed 1
It was performed at 00 mm / min. The tensile yield load at this time is 1
The tensile breaking load was 7.5 kg, the breaking elongation was 20.0 kg, and the breaking elongation was 130%, showing sufficient tensile properties.

Further, when this plastic optical fiber cable was subjected to a combustion test according to the method of UL standard VW-1 which is a standard of flame retardance, both vertical combustion test and horizontal combustion test passed.

[0022]

Example 2 Luminous TB-950 manufactured by Asahi Kasei Corporation and having a diameter of 0.95 mm was used as a plastic optical fiber strand. As a fluorine-containing polyolefin resin used for coating, vinylidene fluoride resin "KYNAR 740"
(Made by Elf Atochem Co., Ltd.) and a soft fluororesin “Sefraral Soft G150” (made by Central Glass) are mixed, and the Shore D hardness at 23 ° C. is 74 and the tensile elongation at break at 400 ° C. is 400%. I was there.

A plastic optical fiber strand TB-950 was introduced into a die directly connected to the melt extruder, and the above-mentioned fluorine-containing polyolefin resin was coated to a thickness of 25 μm to obtain a plastic optical fiber cable having a diameter of 1.00 mm. Was produced. Further, this plastic optical fiber cable was introduced into a die directly connected to the melt extruder in the same manner as above, and nylon 12 resin “Ube nylon 301
4B "(manufactured by Ube Industries, Ltd.) with a thickness of 0.6 mm to obtain a plastic optical fiber cable of the present invention having a diameter of 2.2 mm.

The transmission loss at an optical wavelength of 650 nm of this plastic optical fiber cable was measured by using a fiber loss spectroscope FP-889 (manufactured by Operex Co., Ltd.).
When measured by the cutback method of 52 m-2 m, 12
It was 8 dB / km, and there was almost no increase in loss due to cable formation. This plastic optical fiber cable was left for 1000 hours in a constant temperature oven having a dry heat of 105 ° C., and a change in transmission loss at an optical wavelength of 650 nm was measured. What was 128 dB / km at the time of manufacture was 140 dB / km even after being left for 1000 hours, and the loss increase amount was small.
In addition, the length retention rate is 99.5%, which is almost non-shrinking, the end face of the plastic optical fiber wire is hardly retracted from the coating layer by 0.1 mm, and the cable itself is not deformed. It showed heat resistance.
In addition, the temperature of 85 ℃ and humidity of 95% RH
When left standing for 00 hours, the change in transmission loss at an optical wavelength of 650 nm was measured in the same manner.
m was 163 dB / k even after 1000 hours
m, and the moisture and heat resistance is also excellent.

Next, a tensile test was conducted on this plastic optical fiber cable. The tensile tester "SHIN
Using KOH model TOM-500 ", ASTM
Using the method according to D638, temperature 23 ℃, pulling speed 1
It was performed at 00 mm / min. The tensile yield load at this time is 1
The tensile breaking load was 7.5 kg, the breaking elongation was 110%, and sufficient tensile properties were exhibited.

When this plastic optical fiber cable was subjected to a combustion test according to the method of UL standard VW-1, which is a standard of flame retardance, both vertical combustion test and horizontal combustion test passed.

[0027]

[Comparative Example 1] As a plastic optical fiber strand, Luminus TB-1000 manufactured by Asahi Kasei Corporation and having a diameter of 1.00 mm.
And a polyvinyl chloride resin was used as the coating material. Plastic optical fiber strand TB-1000 was introduced into a die directly connected to the melt extruder, and polyvinyl chloride resin was added.
A plastic optical fiber cable having a diameter of 2.2 mm was produced by coating the optical fiber cable with a thickness of 0.6 mm.

The transmission loss at an optical wavelength of 650 nm of this plastic optical fiber cable was measured by using a fiber loss spectroscope FP-889 (manufactured by Operex).
When measured by the cutback method of 52 m-2 m, 12
It was 8 dB / km, and there was almost no increase in loss due to cable formation. This plastic optical fiber cable was left for 1000 hours in a constant temperature oven having a dry heat of 105 ° C., and a change in transmission loss at an optical wavelength of 650 nm was measured. It was 128 dB / km at the time of manufacture, but after being left for 1000 hours, the transmission loss increased by several thousand dB / km, and it was impossible to measure. The length retention rate was only 87.7%, and the cable was greatly shrunk and shredded as a whole, and was not in a usable state.

Next, a tensile test was conducted on this plastic optical fiber cable. The tensile tester "SHIN
Using KOH model TOM-500 ", ASTM
Using the method according to D638, temperature 23 ℃, pulling speed 1
It was performed at 00 mm / min. The tensile yield load at this time is 9.
0 kg, tensile breaking load is 14.3 kg, breaking elongation is 11
It was 0%, which was insufficient for automobiles.

[0030]

[Comparative Example 2] As a plastic optical fiber strand, Luminous TB-1000 having a diameter of 1.00 mm manufactured by Asahi Kasei Corporation.
And a flame-retardant polyethylene resin was used as the coating material.
A plastic optical fiber strand TB-1000 was introduced into a die directly connected to the melt extruder, and a flame retardant polyethylene resin was coated to a thickness of 0.6 mm to produce a plastic optical fiber cable having a diameter of 2.2 mm. did.

The transmission loss at an optical wavelength of 650 nm of this plastic optical fiber cable was measured by using a fiber loss spectrometer FP-889 (manufactured by Operex).
When measured by the cutback method of 52 m-2 m, 12
It was 7 dB / km, and there was almost no increase in loss due to cable formation. This plastic optical fiber cable was left for 1000 hours in a constant temperature oven having a dry heat of 105 ° C., and a change in transmission loss at an optical wavelength of 650 nm was measured. The value of 127 dB / km at the time of manufacture was 1440 dB / km after being left for 1000 hours, which was a large increase in transmission loss. The length retention rate was only 91.4%, and the cable was greatly shrunk and seemed to be totally broken, and it was not in a usable state.

Next, a tensile test was conducted on this plastic optical fiber cable. The tensile tester "SHIN
Using KOH model TOM-500 ", ASTM
Using the method according to D638, temperature 23 ℃, pulling speed 1
It was performed at 00 mm / min. The tensile yield load at this time is 9.
1 kg, tensile breaking load is 14.7 kg, breaking elongation is 11
It was 5%, which was insufficient for automobiles.

[0033]

[Comparative Example 3] Luminous FB-1000 having a diameter of 1.00 mm manufactured by Asahi Kasei Corporation as a plastic optical fiber strand.
As a coating material, nylon 12 resin “Ube nylon 3014B” (manufactured by Ube Industries) was used. A plastic optical fiber wire F is attached to the die directly connected to the melt extruder.
B-1000 was introduced and the nylon 12 resin was coated to a thickness of 0.6 mm to prepare a plastic optical fiber cable having a diameter of 2.2 mm.

The transmission loss at an optical wavelength of 650 nm of this plastic optical fiber cable was measured by using a fiber loss spectroscope FP-889 (manufactured by Operex).
When measured by the cutback method of 52 m-2 m, it was 48
It was 0 dB / km, and the transmission loss greatly increased due to the cable. Also, 8% by weight of melamine cyanurate as a flame retardant was added to this nylon 12 resin to coat Luminus FB-1000.
The resin was not extruded uniformly, and the surface of the plastic optical fiber cable became uneven. Transmission loss,
The light wavelength was 650 nm, which was very large at 1170 dB / km, and was not very usable.

[0035]

With the cable structure of the present invention, it is possible to manufacture a flame-retardant plastic optical fiber cable that passes the flame-retardant standard without making the polyamide resin flame-retardant. Since the plastic optical fiber cable of the present invention does not contain a flame retardant that adversely affects the plastic optical fiber strand in the coating layer, it has low transmission loss and is stable even at high temperatures, and has flame retardance and mechanical properties. A flame-retardant plastic optical fiber cable having excellent characteristics can be obtained.

The plastic optical fiber cable of the present invention not only exhibits excellent heat resistance in that loss increase and heat shrinkage are extremely small even at high temperatures exceeding 100 ° C.
It also has excellent flame retardance that passes the standard VW-1. Tensile strength also greatly exceeds 10 kg, the cable is close to 10 kg during assembly, a relatively large load is easily applied, and even when it is used for an automobile harness, the flame-retardant plastic optical fiber cable of the present invention does not stretch and is safe. It is strong enough to use. Further, since the plastic optical fiber bare wire is less retracted from the coating layer, it is not necessary to remove the coating even when the connector is attached, and the working process can be simplified. Moreover, since the coating is still attached, there is an advantage that it can be attached without lowering the heat resistance. INDUSTRIAL APPLICABILITY According to the present invention, it becomes possible to apply a plastic optical fiber to a field requiring severe heat resistance, mechanical properties, and flame retardancy such as an automobile field.

Claims (3)

[Claims] 1. A plastic optical fiber strand comprising a core and a sheath, which is made of a resin composition containing at least fluorine atoms on the outside of the plastic optical fiber strand, and the proportion of fluorine atoms or other halogen atoms contained in the resin composition is A plastic optical fiber cable having a first coating layer made of a fluorine-containing polyolefin resin composition of 59% by weight or more and a second coating layer made of a polyamide resin. 2. A plastic optical fiber element wire stretched 1.5 to 3.0 times is coated with a heat-melted fluorine-containing polyolefin resin composition to a thickness of 0.01 to 0.3 mm, and Polyamide resin on it 0.1-1.0m
A plastic optical fiber cable coated to a thickness of m. 3. The flame-retardant plastic optical fiber cable according to claim 2, wherein the coating layer of the fluorine-containing polyolefin resin composition has a thickness of 0.01 to 0.05 mm.