JP3318076B2 - Manufacturing method of large diameter plastic optical fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a large-diameter plastic optical fiber having excellent optical transmission, bending resistance and environmental resistance.

[0002]

2. Description of the Related Art Optical transmission fibers (optical fibers) are generally known as having a two-layer structure having a core-sheath structure comprising a core component having a higher refractive index and a sheath component having a lower refractive index than the core component. I have. Conventionally, as this optical fiber, an inorganic glass-based optical fiber having excellent light transmission properties over a wide wavelength range is known. However, such an optical fiber is not only poor in workability, weak in bending stress, but also expensive. Therefore, it has been put to practical use for long-distance communication. On the other hand, plastic optical fibers containing an organic polymer as a core-sheath component have good workability and are resistant to bending stress, and thus are practically used as optical fibers for short-range communication or decoration. As a core component of the plastic optical fiber, a thermoplastic polymer such as polymethyl methacrylate (hereinafter, referred to as PMMA) or polystyrene is generally used. This is PM
Not only is MA excellent in transparency, processability, weather resistance, etc., but it is possible to make high-performance optical fibers at a relatively low price because it can use composite melt spinning technology as a method for manufacturing PMMA-based optical fibers. This is because there is an advantage.

[0003]

However, even with a plastic optical fiber using PMMA as a core, a large-diameter optical fiber having a diameter of 1 mm or more is easily broken by external stress or bending, and the diameter of the optical fiber is further increased. However, it has become impossible to manufacture large-diameter plastic optical fibers of 10 mm or more. Further, since the heat-resistant temperature of PMMA is 80 to 100 ° C., there is also a disadvantage that the PMMA-based optical fiber cannot be used in a place where the use environment exceeds 100 ° C., such as in an engine room communication of an automobile or mechanical parts. As an optical fiber that solves these inconveniences, the present inventors have filled a transparent tube with a specific core-forming monomer, cured the monomer by light irradiation, and removed the tube to obtain a large-diameter plastic optical fiber ( JP-A-63-40103) and a large-diameter plastic optical fiber comprising a copolymer of an aliphatic allyl monomer and methyl methacrylate (JP-A-63-1).
No. 46004).

However, in the former optical fiber manufacturing method, although a large-diameter plastic optical fiber is produced with high productivity, the core polymer structure contains an aromatic ring.
There is a disadvantage that the core component yellows with time and the optical transmission loss decreases. In the latter optical fiber, a large-diameter plastic optical fiber whose core component is colorless and transparent and light transmission loss is small can be obtained.However, since the core polymer is formed by a thermal polymerization method, there is a disadvantage that its productivity is not good. is there.

The present invention has been made in view of the above background, and has as its object the purpose of the present invention is to provide good transparency, small optical transmission loss, and excellent bending resistance, heat resistance and weather resistance. It is an object of the present invention to provide a method for producing a large-diameter plastic optical fiber showing productivity.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above problems, and as a result, have identified ether di (meth) acrylate and urethane (meth) acrylate having a specific structure and an active energy ray-sensitive catalyst. After injecting the composition blended in the ratio of 1 into a heat-shrinkable sheath tube, the outer surface of the tube is irradiated with ultraviolet rays to be gelled, and then the outer surface of the tube is irradiated with ultraviolet rays having a greater UV illuminance at 350 nm. By irradiating and curing the above core composition, a large-diameter plastic optical fiber having good transparency, small transmission loss, excellent bending resistance, heat resistance and weather resistance, and good productivity is obtained. And completed the present invention.

That is, the present invention provides: (A) 40 to 95 parts by weight of a compound represented by the following general formula (Formula 2):

## STR2 ## _{CH 2 = CR 1 -COO- (R} 3 O) n-CO-CR 2 = CH 2 ( _wherein, R 1, _{R 2} is hydrogen or a methyl group, _{R 3} is 2 to 5 carbon atoms Linear or branched saturated hydrocarbon group, n is 5
(B represents an integer of from 30 to 30) (B) 5 to 60 parts by weight of an aliphatic or alicyclic urethane poly (meth) acrylate having two or more (meth) acryloyloxy groups in one molecule, (C) active energy After injecting a composition comprising 0.005 to 5 parts by weight of the line-sensitive catalyst (the total amount of the components A, B and C is 100 parts by weight) into a heat-shrinkable sheath tube, After the surface is irradiated with ultraviolet rays to be gelled, the outer surface of the tube is irradiated with ultraviolet rays having a greater ultraviolet illuminance at 350 nm, thereby curing and manufacturing the core composition. This is a method for manufacturing an optical fiber.

Each component of the composition for the core component of the large diameter plastic optical fiber of the present invention will be described.

The compound represented by the general formula (Chemical Formula 2), which is the component (A), has a polyalkylene ether diol having a degree of polymerization (n) of 5 to 30 in which both hydroxyl groups at both terminals are acrylic acid, methacrylic acid or Di (meth) acrylates esterified with a derivative of These polyalkylene ether diols are obtained by ring-opening polymerization of ethylene oxide, propylene oxide, tetrahydrofuran, 1-methyltetrahydrofuran, 2-methyltetrahydrofuran, etc., alone or in combination of two or more.
For example, in the case of polybutylene glycol, the degree of polymerization (n) is
If it exceeds 15, it needs to be devised when used because it solidifies at room temperature, but the copolymer of tetrahydrofuran and propylene oxide is liquid even if its (n) is 15 or more, so its handling is extremely preferable. These (co)
It is difficult to obtain a single polyalkylene ether diol as the degree of polymerization (n), and a mixture of (co) polyether diols having different degrees of polymerization in a normal distribution. Therefore, the degree of polymerization (n) is Mean their median. Degree of polymerization
Those made from di (meth) acrylates made from polyether diols with (n) less than 5 do not have sufficient flexibility and have a degree of polymerization (n) higher than 30 Those made from the made di (meth) acrylate lose the toughness of the core polymer. Therefore, the preferred range of the degree of polymerization (n) of the polyether diol is 5 to 3
0, more preferably 7 to 20.

The proportion of the component (A) used is preferably 40 to 95 parts by weight, more preferably 50 to 100 parts by weight of the total amount of the components (A) to (C).
9090 parts by weight. A core polymer prepared using a composition having an amount of the component (A) of less than 40 parts by weight does not have sufficient bending resistance, and the amount of the component (A) is more than 95 parts by weight. The core polymer made has reduced toughness and heat resistance.

The component (B), a urethane poly (meth) acrylate having two or more (meth) acryloyloxy groups in one molecule, is a large-diameter plastic produced using the composition containing the component (B). A component that imparts toughness, flex resistance and heat resistance to the core polymer of the optical fiber,
Specifically, a urethane-forming reaction product of a (meth) acrylate containing a hydroxyl group and a polyisocyanate having two or more isocyanate groups in a molecule, or an isocyanate having two or more isocyanate groups in a molecule, and a polyol , Polyester, polyamide-based diol to react to synthesize a polyisocyanate adduct,
A urethanization reaction product in which a (meth) acrylate containing a hydroxyl group is added to the remaining isocyanate group is mentioned. Urethane poly (meth) acrylate is a component that improves the toughness and heat resistance of the core polymer,
Those having a molecular weight of 400 to 2,000 are preferred.

Specific examples of the polyisocyanate compound include 1,6-hexamethylene diisocyanate, tris (isocyanatohexyl) isocyanurate, 1,4-tetramethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and cyclohexane diisocyanate. , Isophorone diisocyanate, bis (4,4'-isocyanatocyclohexyl) methane, bis (4,4'-isocyanatocyclohexyl) propane, 1,3-bis (isocyanatomethyl) cyclohexane and the like. , Tris (isocyanatohexyl) isocyanurate, isophorone diisocyanate, bis (4,4'-isocyanatocyclohexyl) methane and 1,3-bis (isocyanatomethyl) cyclohexane are particularly preferred.

The polyol used in the synthesis of the polyisocyanate adduct is not particularly limited, but specific examples thereof include ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, trimethylolpropane, pentaerythritol, sorbitol, mannitol, and glycerin. And polyether polyols thereof, polyester polyols synthesized from polyhydric alcohols and polybasic acids, and polyamide polyols such as polycaprolactone polyol.

Specific examples of (meth) acrylates containing a hydroxyl group include 2-hydroxyethyl (meth)
Monoacrylate compounds such as acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc., as well as butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and glycidyl methacrylate Addition products with (meth) acrylic acid and mono (meth) polyethylene glycol and polypropylene glycol
Acrylic esters, mono (meth) acrylic esters of polycaprolactone diol, and the like can be given.

The reaction of the polyisocyanate with various diols and (meth) acrylates containing hydroxyl groups is carried out in the presence of a tin-based catalyst such as n-butyltin dilaurate so that the isocyanate groups and the hydroxyl groups become almost equivalent. And heat at 60-70 ° C for several hours. Since the reactants generally become highly viscous at room temperature, it is preferable to dilute with another diluent monomer during or after the reaction.

Component (B) is used in an amount of 5 to 60 parts by weight, preferably 10 to 100 parts by weight of the total amount of components (A) to (C).
It is in the range of ~ 50 parts by weight. (B) An optical fiber made using a composition having an amount of the component of less than 5 parts by weight has sufficient toughness,
On the other hand, an optical fiber made from a composition in which the amount of the component (B) exceeds 60 parts by weight cannot be made to have heat resistance.

As the active energy ray-sensitive catalyst as the component (C), those which generate a radical source mainly in response to ultraviolet rays having a wavelength of 200 to 400 nm are more preferable, and specific examples thereof include benzoin, benzoin monomethyl ether and benzoin. Isopropyl ether, acetoin, benzyl, benzophenone, p-methoxybenzophenone,
Diethoxyacetophenone, benzyldimethyl ketal, 2,2-diethoxyacetophenone, 1-hydroxycyclohexylphenyl ketone, methylphenylglyoxylate, ethylphenylglyoxylate, 2-hydroxy-2-methyl-1-phenylpropane-1- Carbonyl compounds such as on, tetramethylthiuram monosulfide, sulfur compounds such as tetramethylthiuram disulfide,
Acylphosphine oxides such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and the like can be mentioned. These are used in one kind or in a mixture of two or more kinds. Among them, benzophenone, benzoin isopropyl ether, methylphenylglyoxylate, 1-hydroxycyclohexylphenylketone, benzyldimethylketal, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide are particularly preferred.

Component (C) is used in an amount of 0.005 to 5 parts by weight, more preferably 0.02 to 2 parts by weight, per 100 parts by weight of the total of components (A) to (C). When the amount of the component (C) is less than 0.005 parts by weight, the photocurability of the composition containing the component is insufficient. When the amount exceeds 5 parts by weight, not only the photocurability in the deep part is deteriorated, but also the light It is not preferable because it causes coloring of the core polymer.

The core composition comprising (A) to (C) of the present invention has an improved workability of injecting the composition into a sheath tube and an improved weather resistance of an optical fiber obtained from the composition. It is possible to add other ester monomers in order to achieve this. Specifically, methacrylates, acrylates, or allyl compounds having an aliphatic or alicyclic structure can be used.

Examples of these are methyl (meth)
Acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, dodecyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, butoxyethyl ( Mono (meth) acrylate monomers such as (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and isobornyl (meth) acrylate; 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, neopentyl glycol di (meth)
Di (meth) acrylate monomer such as acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) A) Poly (meth) acrylate monomers such as acrylate and dipentaerythritol hexa (meth) acrylate, and allyl compounds such as diethylene glycol bisallyl carbonate.

These compounds are preferably added in an amount of 1 to 20 parts by weight based on 100 parts by weight of the total amount of the components (A) to (C) as long as the effects of the present invention are not impaired. Good.

The composition for producing a large-diameter plastic optical fiber according to the present invention may contain, if necessary, an organic peroxide, an antioxidant, an anti-yellowing agent, an ultraviolet absorber, a bluing agent, a pigment, an antifoam. An additive such as an agent may be contained in a ratio that does not inhibit the photocurability.

As the sheath material of the large-diameter plastic optical fiber of the present invention, a heat-shrinkable tube made of a translucent fluorine-containing organic polymer is preferable. Materials for the fluorine-containing organic polymer include tetrafluoroethylene / propylene fluoride copolymer (FEP), tetrafluoroethylene / perfluoroalkoxyvinyl ether copolymer (PFA),
A perfluoroalkyl (meth) acrylate polymer, a perfluoroalkyl / alkyl (meth) acrylate copolymer and the like can be mentioned. The refractive index of these sheath tubes is
1.34 to 1.40, the refractive index of the core polymer of the present invention,
Since it is 0.09 to 0.18 lower than 1.49 to 1.52, it is possible to obtain a plastic optical fiber having excellent light transmittance and a large numerical aperture. Among the above, tetrafluoroethylene /
Most preferred are fluorinated propylene copolymer (FEP) and tetrafluoroethylene / perfluoroalkoxy vinyl ether copolymer (PFA).

The heat-shrinkable tube is formed by expanding by 20 to 30% in the diameter direction of the tube while blowing high-pressure air or the like at the time of forming the tube, and then returning to the original shape by heating at the time of use. By using this as the sheath material of the present invention, when the core composition polymerizes and shrinks, the sheath polymer is also heated to an appropriate temperature and shrinks, and follows the shrinkage of the core, so that the core-sheath No peeling at the interface occurs,
The optical transmission loss of the obtained large diameter optical fiber is not impaired. The above-mentioned heat-shrinkable tube preferably has an inner diameter of 2 to 50 mm. More preferably, it is 5 to 30 mm. The thickness of the tube is preferably 0.1 to 1.0 mm. The light-transmitting fluorine-containing organic polymer is generally expensive, and in order to maintain the flexibility of the manufactured optical fiber, the thinner the wall thickness is, the more preferable it is.

In practicing the present invention, a mixture of the components (A) to (C) mixed according to the desired performance was injected into a heat-shrinkable sheath tube made of a light-transmitting fluorine-containing organic polymer. Then, using a light source such as the sun, a chemical lamp for chemical reactions, a halogen lamp, and a metal halide lamp, the UV illuminance at 350 nm from the outer surface of the heat-shrinkable sheath tube is
The first stage of irradiation for gelling by irradiating ultraviolet rays of preferably 0.1 to 10 mW / cm ² for 1 to 30 minutes , more preferably irradiating ultraviolet rays of 0.5 to ⁵ mW / cm ² for 1 to 10 minutes As a result, the core-forming composition undergoes polymerization, gelation, and heat generation due to polymerization, so that the second-stage irradiation is immediately performed. The second irradiation is intended to complete the polymerization of the components for forming the core and to improve the adhesion to the core by sufficiently shrinking the heat-shrinkable sheath tube. The light source includes a high-pressure mercury lamp, a metal halide lamp. It is preferable to use a light source which has a relatively large energy such as the above and can raise the temperature of the irradiation atmosphere. The irradiation condition of the second stage is such that the UV illuminance at 350 nm is lower than the UV illuminance in the first stage.
The irradiation is performed by irradiating large ultraviolet rays, preferably ultraviolet rays having a wavelength of 100 to 500 mW / cm ² , for 10 to 100 seconds. The irradiation atmosphere may be air or an inert gas such as nitrogen or argon. Further, irradiation and heating may be combined.

[0026]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. The abbreviations of the monomers are as follows. MB-65: Nonabutylene glycol dimethacrylate (n
# 9, molecular weight of raw material diol 650) MB-85: dodecabutylene glycol dimethacrylate (n $ 12, molecular weight of raw material diol 850) MPB-100: propylene oxide / tetrahydrofuran = 1/1 random copolymer diol (molecular weight 1000) AEP-70: Ethylene oxide / propylene oxide =
Diacrylate UM 1: 1/1 random copolymer diol (molecular weight 700): urethane dimethacrylate UM 2: bis (4) obtained by reacting 1 mol of isophorone diisocyanate with 2.1 mol of 2-hydroxypropyl methacrylate , 4'-isocyanatocyclohexyl) methane, 1 mol and 2-hydroxypropyl methacrylate, 2.
Urethane dimethacrylate obtained by reacting with 1 mol UM 3: Urethane dimethacrylate obtained by reacting tolylene diisocyanate with 2-hydroxypropyl methacrylate HDDA: 1,6-hexanediol diacrylate DCPM: Dicyclo Pentanyl methacrylate MPG: Methylphenylglyoxylate S-FEP: Heat-shrinkable tube composed of tetrafluoroethylene / fluoropropylene copolymer S-PFA: Heat-shrinkable composed of tetrafluoroethylene / perfluoroalkoxyvinyl ether copolymer Tube FEP: Tube made of tetrafluoroethylene / fluoropropylene copolymer PFA: Tube made of tetrafluoroethylene / perfluoroalkoxyvinyl ether copolymer

[0027]

Example 1 80 parts by weight of nonabutylene glycol methacrylate (MB-65), isophorone diisocyanate,
A composition obtained by mixing 20 parts by weight of urethane dimethacrylate (UM 1) synthesized from 2.1 mol of 2-hydroxypropyl methacrylate and 2.1 mol, and 0.03 part by weight of 2,4,6-trimethylbenzoyldiphenylphosphine oxide (TPO),
12.8mm inner diameter, 0.3mm wall thickness, 3m long ethylene fluoride
It was injected into a heat-shrinkable tube made of fluorinated propylene copolymer (FEP) and irradiated with sunlight having an ultraviolet irradiance of 350 nm of ² mW / cm ² for 5 minutes. Immediately after heating to ℃, the UV irradiance of 350 nm was irradiated by a metal halide lamp of 120 W / cm, which is 200 mW / cm ² , for 30 seconds and the outer diameter was 12 mm and the length was 2.5 m
Large-diameter plastic optical fiber was manufactured. Evaluate the manufactured large-diameter plastic optical fiber by the following evaluation method,
The results are shown in Tables 1 and 2.

Injection workability: The workability of injection of the monomer mixture into the sheath tube was determined. : Easy to inject. ×: Air bubbles are hardly removed and injection is difficult. Optical transmission loss: measured by a cutback method using He-Ne laser light (wavelength: 633 nm). Bending resistance test: A molded large-diameter plastic optical fiber was wound around a metal rod having a diameter of 50 mm ten times, held at room temperature for one hour, and unwrapped, and the optical transmission loss was measured. Heat resistance: After leaving the optical fiber in a hot air dryer at 120 ° C. for 500 hours, the change in outer diameter was visually determined, and the optical transmission loss was measured. Weather resistance: The change after exposing the molded large-diameter plastic optical fiber to the outdoors for one month was visually judged, and the optical transmission loss was measured.

[Table 1]

[Table 2]

[0029]

Examples 2 to 4 Large-diameter plastic optical fibers were produced and evaluated in the same manner as in Example 1 except that the monomer composition for forming the core component and the tube for forming the sheath were used in the proportions shown in Table 1. The results are shown in Table 2.

[0030]

Comparative Examples 1 to 5 Large-diameter plastic optical fibers were produced and evaluated in the same manner as in Example 1 except that the core component monomer and the sheath component tube were used in the proportions shown in Table 1. The results are shown in Table 2.

[0031]

As demonstrated by the above examples,
According to the present invention, it is possible to obtain a large-diameter plastic optical fiber having good transparency, small transmission loss, excellent bending resistance, heat resistance, and weather resistance, and showing good productivity.

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Katsumi Yonekura 4-160 Sunadabashi, Higashi-ku, Nagoya City, Aichi Prefecture Mitsubishi Rayon Co., Ltd. Product Development Laboratory (56) References JP-A-4-270709 (JP, A JP-A-63-256902 (JP, A) JP-A-62-269905 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 2/00-2/50 C08F 290 / 06 G02B 6/00 G02B 6/10 G02B 6/16-6/22 G02B 6/44

Claims (1)

(57) [Claims] 1. A compound (A) 40 to 95 parts by weight represented by the following general formula (1), ## STR1 ## _{CH 2 = CR 1 -COO- (R} 3 O) n-CO-CR 2 = CH ₂ (wherein, R ₁ and R ₂ are hydrogen or a methyl group, R ₃ is a linear or branched saturated hydrocarbon group having 2 to 5 carbon atoms, and n is 5
(B represents an integer of from 30 to 30) (B) 5 to 60 parts by weight of an aliphatic or alicyclic urethane poly (meth) acrylate having two or more (meth) acryloyloxy groups in one molecule, (C) active energy After injecting a composition comprising 0.005 to 5 parts by weight of a line-sensitive catalyst into the heat-shrinkable sheath tube, wherein the total amount of the components A, B and C is 100 parts by weight, After irradiating the surface with ultraviolet rays to cause gelation, by irradiating the outer surface of the tube with ultraviolet rays having a greater ultraviolet illuminance at 350 nm,
A method for producing a large-diameter plastic optical fiber, comprising producing the core composition by curing the core composition.