JPS61114209A - Plastic optical fiber - Google Patents

Abstract

PURPOSE:To improve the optical transmission characteristic of a plastic optical fiber from a visible light region to near IR light region by using a polymer obtd. from the monomer 2,3,4,5,6-pentafluorostyrene expressed by the specific constitutional formula as a core component resin. CONSTITUTION:The core component resin to be used is the polymer obtainable from the monomer of the fluorostyrene (F5-styrene) expressed by the formula. All or part of the hydrogen atoms of said monomer may be substd. with deuterium atoms or fluorine atoms. The core component resin may be a copolymer with the vinyl monomer which can be copolymerized with the monomer expressed by the formula. The compounding ratio thereof is preferably about <=50wt%, more preferably <=25wt% and most preferably <=10wt%. The vinyl monomer of which the C-H bond is deuterated or is fluorinated is most preferably used in terms of the optical transmission characteristic. The core component resin is preferably polymerized by block polymn.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a plastic optical fiber having a core and sheath structure in which a polymer obtained from a monomer having a specific fluorinated structural formula is used as a core component. The present invention relates to a plastic optical fiber that, when used as a resin, has excellent light transmission properties over the visible light region to the near-infrared light region.

(Differences from conventional technology) Plastic optical fibers are made of inorganic glass,
In particular, compared to quartz glass fiber, it has excellent flexibility even when made with a large diameter, and it is easy to obtain a lightweight and high numerical aperture, which reduces connection loss with the light source and makes it easier to produce large lids industrially. It is characterized by being extremely inexpensive and is used in short-distance transmission systems.

Polymethyl methacrylate, polystyrene, polycarbonate, etc., which have good transparency, are generally used as core component resins for plastic optical fibers, but they have the disadvantage of inferior light transmission properties compared to quartz glass fibers. LEDs are inexpensive light-emitting elements with high luminous intensity used in optical transmission systems.
LD has an emission wavelength in the vicinity of 660 to 900 nm, and from this point of view as well, it is desired to develop a plastic optical 7-eyeper that has excellent light transmission properties over the visible light region to the near-infrared light region.

(Means and Effects for Solving the Problems) As a result of intensive studies by the present inventors in order to improve the above-mentioned drawbacks, the present inventors have found that By using this polymer as a core component resin, we have developed a plastic optical fiber with dramatically improved optical transmission properties over the visible light region to near-infrared light region, and completed the present invention.

That is, the present invention uses a polymer obtained from the monomer 2,3,4,5,6-pentafluorostyrene having the structural formula shown below as a core component resin in a plastic optical fiber having a core and sheath structure. It is a plastic optical fiber characterized by:

CH2=CTl According to studies by the present inventors, synthetic polymers generally have C-H bonds in their molecular structure, and harmonics of infrared absorption are a major factor in reducing optical transmission properties. There is one. In particular, light transmission properties in the near-infrared region of 600 to 900 nm, which is the emission wavelength of inexpensive and high emission intensity LEDs and LDs, are greatly reduced.

Furthermore, the wavelength positions of the peaks and troughs of the absorption intensity of harmonics of this infrared absorption vary due to differences in molecular structure, forming a so-called loss window with excellent optical transmission at a specific wavelength.

The present inventors have completed the present invention by applying the above-described phenomenon industrially. That is, by fluorinating the 0-E bond in the molecular structure, the infrared absorption of the 0-1) bond is shifted to a longer wavelength region, and by fluorinating the specific (3-H bond) in the molecular structure, It has become possible to improve optical transmission properties by adjusting the wavelength position of the so-called loss window to match the emission wavelength of the light emitting element in the visible light region to the near infrared region.

The core component resin used in the present invention is a polymer obtained from a fluorinated styrene (F6-styrene) monomer having the structural formula shown below.

All or some of the hydrogen atoms in the above monomers may be substituted with deuterium atoms or fluorine atoms.

The above monomers are listed in J, chem, 80C, 166 (
1959).

J, Res, Nati! , Bur 8td 67m,
481 (196B).

The core component resin used in the present invention may be a copolymer of the monomer represented by the above structural formula and a copolymerizable vinyl monomer, and the blending ratio thereof is preferably 5 Qwt% or less,
It is more preferably 25 wt% or less, and even more preferably 10 wt% or less. Also, from the perspective of optical transmission, 0-■
It is most preferable to use a vinyl monomer whose bond is deuterated or fluorinated.

The core component resin used in the present invention is preferably polymerized by bulk polymerization from the viewpoint of optical transmission properties.

The monomer used in the present invention is purified by removing impurities using a distillation device with high rectification effect or by performing appropriate pretreatment and then further distillation to obtain a high purity product free from dust, transition metals, coloring impurities, etc. It is made into a monomer.

The polymerization initiator used in the present invention may be arbitrarily selected depending on the desired polymerization rate, polymerization temperature, and polymerization rate, such as azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1 -carbonitrile), benzoyl peroxide.

Examples include t-butyl peroxide. There is no particular limitation on the amount used, and it may be used within a range that allows appropriate polymerization control.

Any molecular regulator used in the present invention may be selected as long as it does not cause adverse tV such as coloring of the final polymer, such as n-butyl mercaptan, t-butyl mercaptan, n-dodecyl mercaptan, etc. Examples include mercaptan and t-dodecyl mercaptan. There is no particular limitation on the amount used, and the weight average molecular weight of the final polymer is
, o o o to 150.000.

As for the method of charging the polymerization initiator and molecular weight regulator used in the present invention, since the amount used is small, it is preferable to dissolve it in a small amount of monomer under environmental conditions free from dust and the like, and then charge it to the polymerization machine. . In order to avoid unexpected contamination with dust, distillable polymerization initiators such as t-butyl peroxide and n-octyl azobutane are used, and distillable molecular weight regulators such as n-butyl mercaptan and t-butyl peroxide are used. - If butyl mercaptan or the like is used, it becomes possible to employ a distillation preparation method. It is also possible to dissolve a polymerization initiator and a molecular weight regulator in a small amount of monomer, and then pass the mixture through a filter and charge it into the mixer.

Is the above method sufficient to purify the monolayer, polymerization initiator, and molecular TA1M moderator used to remove dust from entering the polymer? Above all, it is important to thoroughly remove dust from inside the polymerization machine that produces the polymer.
As a method for this, the present inventors previously filed a patent application filed in 1982-
It is preferable to remove as much dust as possible from inside the polymerization machine before polymerization by employing the methods described in Japanese Patent Application No. 42761, Japanese Patent Application No. 58-42762, and the like.

The sheath component resin used in the present invention is not particularly limited as long as it has a lower refractive index than the core component resin shown in the present invention and has relatively excellent transparency.
Any material may be selected depending on the desired numerical aperture and spinnability. Examples of such sheath component resins include fluorine-containing polymers. Specific examples include homopolymers or copolymers of tetrafluoroethylene, vinylidene fluoride, and hexafluoropropylene, homopolymers of fluorinated alcohol esters of methacrylic acid, and methacrylic acid esters of these and methyl methacrylate. kind,
Examples include acrylic acid esters such as methyl acrylate, copolymers with acrylic acid, methacrylic acid, etc.

Among these fluorine-containing polymers, a copolymer of tetrafluoroethylene and vinylidene fluoride is preferred from the viewpoint of price, manufacturing method, spinnability, heat resistance, etc.; Copolymers obtained by adding and copolymerizing possible monomers are also preferred. On the other hand, from the viewpoint of optical transmission, among the fluorine-containing polymers, the homopolymer of the 77X alcohol ester of methacrylic acid is preferable, and the homopolymer is mainly composed of a fluorinated alcohol ester of methacrylic acid and methyl methacrylate. More preferred are copolymers with monomers such as IH, IB, 5H-octafluoropentyl methacrylate and methyl methacrylate, IH, IH, 2H, 2H-hebutadecafluorodecyl methacrylate and methacrylic acid. Copolymer with methyl, 2
, 2,3,8,8-pentafluoropropyl methacrylate and methyl methacrylate are particularly preferred. Also preferred is a copolymer obtained by copolymerizing a fluorinated alcohol ester of methacrylic acid and an eighth monomer copolymerizable with methyl methacrylate.

The plastic optical fiber of the present invention is produced from the core component resin and sheath component resin produced as described above. As for the manufacturing method, any commonly used method may be used, such as spinning the core component resin and then coating it with the sheath component resin, or composite melt spinning of the core component resin and the sheath component resin. It can be adopted without any particular restrictions.

The plastic optical fiber obtained in this way has a core and sheath structure with a sheath layer with a thickness of 5 to 20 μm, and from the viewpoint of connection with the fiber and connection with a light source, it is preferable to have a diameter of 0.8 to 8 μm. Preferably 0.5~
2 dragons are more preferred, and 0.8 to 1.2 dragons are particularly preferred.

The plastic optical fiber obtained as described above uses a polymer obtained from a monomer having a specific fluorinated structure shown in the present invention as a core component resin, so it is compared to conventional plastic optical fibers. This dramatically improves optical transmission performance, expands the possible transmission range, and dramatically expands the range of applications such as in-building communications.

(Example) The optical fiber of the present invention will be described below based on Examples. The optical transmission property was evaluated by using a halogen lamp as a light source and calculating the transmission loss using the following formula from the input intensity (Io) and output intensity (I) of the plastic optical fiber per length L).

Transmission loss (dB/Km) = -101! Og(I/I
o)/L Example 1 2. A monomer mixture of 100 parts of 3,4,5.6-pentafluorostyrene, 0.0085 parts of azobis-tert-octane, and 0.1 part of lauryl mercaptan was introduced into a glass-lined polymerization machine. Continuous bulk polymerization was carried out at a feeding temperature of 180° C. and an average residence time of 6 hours.

The obtained approximately 50% polymer solution is supplied to a multi-stage vent extruder to remove unpolymerized monomers, and then introduced to a composite melting device, where a tetrafluoroethylene-vinylidene fluoride copolymer is added as a sheath component resin. A plastic optical fiber having a core and sheath structure with a diameter of 1 mm was obtained by composite melt spinning. The transmission loss is 12 at 660 nm.
0dB/Km.

780 parts m 250 dB/Km, 850 parts m 41
0 dB/Km, and showed excellent optical transmission properties in the visible light region to near-infrared light region.

Examples 2 to 8 Plastic optical fibers were obtained by using the same core component resin, polymerization method, demonomer removal, and composite melt spinning as in Example 1, but changing the sheath component resin. The transmission loss of the obtained plastic optical fiber is shown in the table below.

MMA...Methyl methacrylate 8FM...IH, IH, 5H-octafluoropentyl methacrylate 5FM...2.2.8.8.8-Pentafluoropropyl methacrylate Example 4 2.3, 4, 5. 60 parts of 6-bentafluorostyrene,
2. A monomer mixture of 40 parts of 3,4,5.6-deuterated styrene, 0.085 parts of azobis-tert-octane, and 0.1 part of lauryl mercaptan was polymerized and depilated in the same manner as in Example 1. The Zimmer 1 composite was melt spun to obtain fibers with a diameter of 1 mm. Transmission loss is 660 parts m 185d
B/Km, 780 parts m 265dB/Km.

8501m 480dB/Kin, visible light range~
It exhibited excellent optical transmission properties in the near-infrared region.

Claims (1)

[Claims] (1) In plastic optical fibers having a core and sheath structure, monomers 2, 3, 4 of the following structural formula
, 5,6-pentafluorostyrene as a core component resin. ▲Contains mathematical formulas, chemical formulas, tables, etc.▼