JP2019061157A - Optical fiber - Google Patents

Abstract

To provide an optical fiber capable of having appropriate coating removability, and maintaining an adhesion between a glass fiber and a coating resin layer even in a state of being immersed in oil.SOLUTION: An optical fiber 10 comprises a glass fiber 13, a primary resin layer 14 for coating an outer periphery of the glass fiber 13, and a secondary resin layer 15 for coating an outer periphery of the primary resin layer 14. A contact angle of the primary resin layer 14 with respect to a mineral oil is 9.0 to 15.0° at 23°C, and an equilibrium elastic modulus of the secondary resin layer 15 is 0.23 to 0.80 GPa.SELECTED DRAWING: Figure 1

Description

  The present invention relates to optical fibers.

  In general, an optical fiber has a coating resin layer for protecting a glass fiber which is a light transmitting body.

  In patent document 1, adjusting the contact angle with respect to the water of the coating material of an optical fiber is examined.

JP, 2012-27317, A

  When the optical fiber is immersed in an oil such as mineral oil, the coating resin layer may absorb the oil and the adhesion of the coating resin layer to the glass fiber may be reduced. The optical fiber is required to have a coating resin layer having high adhesion even if immersed in oil as well as water. On the other hand, when connecting an optical fiber, it is necessary to remove a part of coating resin layer from glass fiber. If the adhesion of the coating resin layer to the glass fiber is too high, when the coating resin layer is removed from the glass fiber, part of the coating resin layer may remain on the outer periphery of the glass fiber.

  Then, an object of this invention is to provide the optical fiber which has suitable coating removal property and can maintain the adhesive force of glass fiber and a coating resin layer, even if it immerses in oil.

  An optical fiber according to an aspect of the present invention comprises a glass fiber, a primary resin layer covering the outer periphery of the glass fiber, and a secondary resin layer covering the outer periphery of the primary resin layer, and contacting mineral oil with the primary resin layer The angle is 9.0 to 15.0 ° at 23 ° C., and the equilibrium elastic modulus of the secondary resin layer is 0.23 to 0.80 GPa.

  According to the present invention, it is possible to provide an optical fiber having appropriate removability for covering and capable of maintaining the adhesion between the glass fiber and the covering resin layer even when immersed in oil.

It is a schematic sectional drawing which shows an example of the optical fiber which concerns on this embodiment.

Description of the embodiment of the present invention
First, the contents of the embodiment of the present invention will be listed and described. An optical fiber according to an aspect of the present invention comprises a glass fiber, a primary resin layer covering the outer periphery of the glass fiber, and a secondary resin layer covering the outer periphery of the primary resin layer, and contacting mineral oil with the primary resin layer The angle is 9.0 to 15.0 ° at 23 ° C., and the equilibrium elastic modulus of the secondary resin layer is 0.23 to 0.80 GPa.

  The optical fiber of the present embodiment can achieve both the adhesion of the coating resin layer and the removability of the coating before and after immersion in oil. If the contact angle of the mineral oil with the primary resin layer is a certain value or more, the affinity between the primary resin layer and the oil is low, and the primary resin layer repels oil, making it difficult to swell, and the secondary It is thought that absorption of oil can be suppressed and swelling of the primary resin layer can be suppressed by increasing the equilibrium elastic modulus of the resin layer.

  The primary resin layer may contain a cured product of a resin composition containing a urethane oligomer, a monomer, a photopolymerization initiator and a silane coupling agent. This makes it easy to improve the adhesion of the primary resin layer to the glass fiber.

  The resin composition may contain 0.5 to 1.5% by mass of a silane coupling agent. This makes it easy to adjust the adhesion between the glass fiber and the primary resin layer.

  The monomer may contain a polar monomer. This makes it easy to adjust the contact angle of the mineral oil to the primary resin layer.

Details of the Embodiment of the Present Invention
Specific examples of the optical fiber according to the embodiment of the present invention will be described below with reference to the drawings. The present invention is not limited to these exemplifications, but is shown by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the following description, the same reference numerals are given to the same elements in the description of the drawings, and the redundant description will be omitted.

(Optical fiber)
FIG. 1 is a schematic cross-sectional view showing an example of an optical fiber according to an embodiment of the present invention. The optical fiber 10 includes a glass fiber 13 and a coating resin layer 16 provided on the outer periphery of the glass fiber 13. The covering resin layer 16 includes a primary resin layer 14 provided in contact with the outer periphery of the glass fiber 13 and a secondary resin layer 15 covering the primary resin layer 14.

  The glass fiber 13 transmits the light introduced into the optical fiber 10. The glass fiber 13 has a core 11 and a cladding 12, and the cladding 12 surrounds the core 11. The cladding 12 has a refractive index lower than that of the core 11. The core 11 and the cladding 12 mainly contain glass such as quartz glass. For example, quartz to which germanium is added can be used for the core 11, and pure cladding or quartz to which fluorine is added is used for the cladding 12 be able to.

  In FIG. 1, for example, the outer diameter (D2) of the glass fiber 13 is about 125 μm, and the diameter (D1) of the core 11 constituting the glass fiber 13 is about 7 to 15 μm.

  The thickness of the covering resin layer 16 is usually about 60 to 70 μm. The thickness of each layer of the primary resin layer 14 and the secondary resin layer 15 may be about 10 to 50 μm. For example, the thickness of the primary resin layer 14 is 35 μm, and the thickness of the secondary resin layer 15 is 25 μm. May be The outer diameter of the optical fiber 10 may be about 245 to 265 μm.

  From the viewpoint of improving the adhesion to the glass fiber 13, the primary resin layer 14 can be formed by curing a resin composition containing a urethane oligomer, a monomer, a photopolymerization initiator and a silane coupling agent. That is, the primary resin layer 14 can contain a cured product of a resin composition containing a urethane oligomer, a monomer, a photopolymerization initiator and a silane coupling agent.

  The urethane oligomer can be prepared by reacting a polyol, a polyisocyanate and a hydroxyl group-containing (meth) acrylate. Here, (meth) acrylate means acrylate or a methacrylate corresponding thereto. The same applies to (meth) acryloyl.

  Examples of the polyol include polytetramethylene glycol, polypropylene glycol and bisphenol A / ethylene oxide addition diol. Examples of the polyisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, isophorone diisocyanate and dicyclohexylmethane 4,4'-diisocyanate. As the hydroxyl group-containing (meth) acrylate, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 1,6-hexanediol mono (meth) acrylate, pentaerythritol tri (meth) acrylate, 2 -Hydroxypropyl (meth) acrylate and tripropylene glycol di (meth) acrylate are mentioned.

  A monohydric alcohol may be used at the time of urethane oligomer synthesis. As a monohydric alcohol, for example, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-propanol, 1-pentanol, 2-pentanol, 3-pentanol , 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2,2-dimethyl-1-propanol, capryl alcohol, lauryl alcohol, myristyl Alcohol, cetyl alcohol, stearyl alcohol and oleyl alcohol can be mentioned.

  When preparing a urethane oligomer, a catalyst, a polymerization inhibitor or the like may be used. Examples of the catalyst include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin malate, dibutyltin bis (2-ethylhexyl mercaptoacetate), dibutyltin bis (isooctyl mercaptoacetate) and dibutyltin oxide. Examples of the polymerization inhibitor include methoquinone and hydroquinone.

  As the monomer, a monofunctional monomer having one polymerizable group or a polyfunctional monomer having two or more polymerizable groups can be used. The monomers may be used as a mixture of two or more.

  Examples of monofunctional monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, tert-butyl (meth) acrylate, Isobutyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, isoamyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (Meth) acrylate, isooctyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (meth) acrylate, phenoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, Zyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyl oxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, nonylphenol polyethylene glycol (meth) acrylate, nonyl phenoxy polyethylene glycol (meth) acrylate, (Meth) acrylate monomers such as isobornyl (meth) acrylate; (meth) acrylic acid, (meth) acrylic acid dimer, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, ω-carboxy-polycaprolactone (meth) Carboxyl group-containing monomers such as acrylates; N- (meth) acryloyl morpholine, N-vinyl pyrrolidone, N-vinyl caprolactam, N- (meth) acryloyl Heterocycle-containing (meth) acrylates such as piperidine, N- (meth) acryloyl pyrrolidine, 3- (3-pyridyl) propyl (meth) acrylate; maleimide-based monomers such as maleimide, N-cyclohexyl maleimide, N-phenyl maleimide (Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-methyl (meth) acrylamide, N-butyl (meth) acrylamide, N-substituted such as N-butyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N- [3- (dimethylamino) propyl] acrylamide, N- methylol (meth) acrylamide, N- methylol propane (meth) acrylamide and the like Amide based monomer Aminoalkyl (meth) acrylates such as aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, tert-butylaminoethyl (meth) acrylate Monomers; and succinimide monomers such as N- (meth) acryloyloxymethylene succinimide, N- (meth) acryloyl-6-oxyhexamethylene succinimide, and N- (meth) acryloyl-8-oxyoctamethylene succinimide.

  Examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, Di (meth) acrylate of alkylene oxide adduct of bisphenol A, tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate of hydroxypivalate, 1,4-butanediol di (meth) acrylate, 1,6 -Hexanediol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, 1,12-dodecanediol di (meth) acrylate, 1,14-tetradecanediol di (Meth) acrylate, 1,16-hexadecanediol di (meth) acrylate, 1,20-eicosanediol di (meth) acrylate, isopentyldiol di (meth) acrylate, 3-ethyl-1,8-octanediol di ( Meta) acrylate, EO adduct of bisphenol A di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylol octane tri (meth) acrylate, trimethylol propane polyethoxy tri (meth) acrylate, trimethylol propane polypropoxy Tri (meth) acrylate, trimethylolpropane polyethoxypolypropoxy tri (meth) acrylate, tris [(meth) acroyloxyethyl] isocyanurate, pentaerythritol tri (meth) Crylate, pentaerythritol polyethoxy tetra (meth) acrylate, pentaerythritol polypropoxy tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipenta Erythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate and caprolactone modified tris [(meth) acryloyloxyethyl] isocyanurate.

  The monomer preferably contains a polar monomer, since it is easy to adjust the contact angle of the mineral oil to the primary resin layer. Polar monomers such as N-vinylpyrrolidone, N-vinylcaprolactam, (meth) acryloyl morpholine, (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-isopropyl (meth) It is preferable to include at least one selected from the group consisting of acrylamide and N- [3- (dimethylamino) propyl] acrylamide.

  From the viewpoint of achieving both water resistance and oil resistance, the content of the polar monomer is preferably 8.0 to 22.0% by mass, and more preferably 9.0 to 20.0% by mass, based on the total amount of the resin composition. preferable.

  The photopolymerization initiator can be appropriately selected and used from known radical photopolymerization initiators. As a photopolymerization initiator, for example, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2, 4,4-trimethylpentyl phosphine oxide, 2,4,4-trimethyl benzoyl diphenyl phosphine oxide, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one (Irgacure 907, BASF Company company), 2,4,6-trimethyl benzoyl diphenyl phosphine oxide (Irgacure TPO, manufactured by BASF) and bis (2,4,6-trimethyl benzoyl) phenyl phosphine oxide (Irgacure 819, manufactured by BASF)

  The silane coupling agent is not particularly limited as long as it does not hinder the curing of the resin composition, and any silane coupling agent can be used, including publicly known and commonly used silane coupling agents. As a silane coupling agent, for example, tetramethyl silicate, tetraethyl silicate, mercaptopropyltrimethoxysilane, vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-methoxy-ethoxy) silane, β- (3,4-epoxycyclohexyl) -Ethyltrimethoxysilane, dimethoxydimethylsilane, diethoxydimethylsilane, 3-acryloxypropyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-methacryloxypropyl Trimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethyldimethoxysilane, N-phenyl-γ- Minopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, bis- [3- (triethoxysilyl) propyl] tetrasulfide, bis- [3- (Triethoxysilyl) propyl] disulfide, γ-trimethoxysilylpropyldimethylthiocarbamyl tetrasulfide and γ-trimethoxysilylpropylbenzothiazyl tetrasulfide. The adhesion between the glass fiber 13 and the primary resin layer 14 can be adjusted by using a silane coupling agent.

  The amount of the silane coupling agent contained in the resin composition is preferably 0.5 to 1.5% by mass based on the total amount of the resin composition from the viewpoint of adjusting the balance between the adhesion and the removability of the coating. And 0.5 to 1.3% by mass is more preferable, and 0.5 to 1.0% by mass is more preferable.

From the viewpoint of suppressing the swelling of the covering resin layer to oil, the contact angle of the mineral oil with respect to the primary resin layer 14 is 9.0 to 15.0 ° at 23 ° C., preferably 11.0 to 15.0, 12 0.degree. To 15.0.degree. The contact angle of mineral oil can be measured using a cured product of a resin composition formed by curing using ultraviolet light of energy of 1000 mJ / cm ² . Examples of mineral oils include, but are not limited to, those sold by Sigma-Aldrich.

  The secondary resin layer 15 can be formed, for example, by curing a resin composition containing a urethane oligomer, a monomer, and a photopolymerization initiator. That is, the secondary resin layer 15 can contain the hardened | cured material of the resin composition containing a urethane oligomer, a monomer, and a photoinitiator. It does not specifically limit as a urethane oligomer, a monomer, and a photoinitiator, You may select suitably from the compound illustrated by the resin composition which forms a primary resin layer.

  From the viewpoint of maintaining the adhesion between the glass fiber and the coating resin layer after immersion in oil, the equilibrium elastic modulus of the secondary resin layer 15 is 0.23 to 0.80 GPa, more preferably 0.25 to 0.70 GPa. Preferably, 0.30 to 0.60 GPa is more preferable. The equilibrium elastic modulus of the secondary resin layer 15 can be measured from a change in elastic modulus (E ′) at a temperature of 20 to 150 ° C. at a frequency of 11 Hz using a dynamic viscoelasticity measuring device. The value at which E 'reaches equilibrium is the equilibrium elastic modulus.

  Hereinafter, the result of the evaluation test using the Example and comparative example which concern on this invention is shown, and this invention is demonstrated in more detail. The present invention is not limited to these examples.

(Urethane oligomer)
The polypropylene glycol diol was reacted with isophorone diisocyanate and hydroxyethyl acrylate to obtain a urethane oligomer a.

  A polypropylene glycol diol having a molecular weight of 2000 was reacted with isophorone diisocyanate and hydroxyethyl acrylate to obtain a urethane oligomer b1.

  Isophorone diisocyanate and hydroxyethyl acrylate were reacted with a polypropylene glycol diol having a molecular weight of 1000 to obtain a urethane oligomer b2.

  A polypropylene glycol diol having a molecular weight of 700 was reacted with isophorone diisocyanate and hydroxyethyl acrylate to obtain a urethane oligomer b3.

(Resin compositions A1 to A9)
Urethane oligomer a, EO modified nonylphenyl acrylate, N-vinylcaprolactam, acryloyl morpholine, 2,4, 6-trimethyl benzoyl diphenyl phosphine oxide, and 3-mercaptopropyl tri- trine by the compounding quantity (mass part) shown in Table 1 Resin compositions A1 to A9 were prepared by mixing ethoxysilane.

(Resin composition B1)
Resin composition B1 by mixing 50 parts by mass of urethane oligomer b1, 20 parts by mass of isobornyl acrylate, 28 parts by mass of epoxy (meth) acrylate, and 2 parts by mass of 2,4,6-trimethyl benzoyl diphenyl phosphine oxide Was prepared.

(Resin composition B2)
A resin composition B2 was prepared in the same manner as the resin composition B1, except that the urethane oligomer b1 was changed to the urethane oligomer b2.

(Resin composition B3)
A resin composition B3 was prepared in the same manner as the resin composition B1, except that the urethane oligomer b1 was changed to the urethane oligomer b3.

[Optical fiber]
Example 1
A primary resin layer with a thickness of 35 μm is formed using the resin composition A1 on the outer periphery of a 125 μm diameter glass fiber composed of a core and a clad, and a secondary 25 μm thickness using the resin composition B1 on the outer periphery A resin layer was formed to obtain an optical fiber having a diameter of 245 μm. The linear velocity was 1500 m / min.

(Example 2)
An optical fiber was obtained in the same manner as in Example 1 except that the primary resin layer was formed using the resin composition A2.

(Example 3)
An optical fiber was obtained in the same manner as in Example 1 except that the primary resin layer was formed using the resin composition A3.

(Example 4)
An optical fiber was obtained in the same manner as in Example 1 except that the primary resin layer was formed using the resin composition A4.

(Example 5)
An optical fiber was obtained in the same manner as in Example 1 except that the primary resin layer was formed using the resin composition A5.

(Example 6)
An optical fiber was obtained in the same manner as in Example 3 except that the secondary resin layer was formed using the resin composition B2.

(Example 7)
An optical fiber was obtained in the same manner as in Example 3 except that the secondary resin layer was formed using the resin composition B3.

(Example 8)
An optical fiber was obtained in the same manner as in Example 1 except that the primary resin layer was formed using the resin composition A8.

(Example 9)
An optical fiber was obtained in the same manner as in Example 1 except that the primary resin layer was formed using the resin composition A9.

(Comparative example 1)
An optical fiber was obtained in the same manner as in Example 1 except that the primary resin layer was formed using the resin composition A6.

(Comparative example 2)
An optical fiber was obtained in the same manner as in Example 1 except that the primary resin layer was formed using the resin composition A7.

[Evaluation]
The produced optical fiber was evaluated as follows. The evaluation results are shown in Tables 2 and 3.

(Contact angle of mineral oil)
After the resin composition for the primary resin layer was applied onto a glass substrate, it was cured by irradiation with ultraviolet light of 1000 mJ / cm ^{2 in} a nitrogen atmosphere to form a resin layer having a thickness of 200 μm. A D bulb was used for the ultraviolet lamp.
Then, using a contact angle meter ("Drop Master 500" manufactured by Kyowa Interface Science Co., Ltd.), the contact angle of mineral oil ("Mineral oil light" manufactured by Sigma-Aldrich) to the resin layer was measured at 23 ° C. After one drop of mineral oil was dropped on the resin layer with a syringe and stabilized, the value measured one minute after that was taken as the contact angle.

(Equilibrium elastic modulus)
The coated resin layer was peeled from the glass fiber in a pipe shape by immersing the optical fiber in ethanol: acetone (3: 7). Then, after storing the peeled coated resin layer in an environment of 25 ° C. and 50% RH for 12 hours or more, a dynamic viscoelasticity measuring apparatus (Solid S analyzer RSA-II) is used at a frequency of 11 Hz and a temperature of 20 to 150 ° C. The change in elastic modulus (E ') was measured, and the value at which E' reached equilibrium was taken as the equilibrium elastic modulus of the secondary resin layer.

(Pull-out force)
About the produced optical fiber, the pullout force at the time of draw | extracting out a coating resin layer from glass fiber was evaluated based on the method as described in Unexamined-Japanese-Patent No. 2017-007896 grade | etc.,. The pullout force at 23 ° C. was evaluated as “A” for less than 1 g, “B” for 1 kg or more and less than 2 kg, and “C” for 2 kg or more.

(Peeling force maintenance rate)
About the produced optical fiber according to IEC 60793-1-32, the peeling force at the time of removing a coating resin layer from glass fiber was measured before and after immersing an optical fiber in mineral oil for 30 days at 85 ° C. The retention of peel strength after immersion in mineral oil for 30 days was 70% or more as “A”, 60% or more and less than 70% as “B”, and less than 60% as “C”.

  DESCRIPTION OF SYMBOLS 10 ... Optical fiber, 11 ... Core, 12 ... Clad, 13 ... Glass fiber, 14 ... Primary resin layer, 15 ... Secondary resin layer, 16 ... Coating resin layer.

Claims (4)

A glass fiber, a primary resin layer covering the outer periphery of the glass fiber, and a secondary resin layer covering the outer periphery of the primary resin layer;
The optical fiber whose contact angle of mineral oil with respect to the said primary resin layer is 9.0-15.0 degrees at 23 degreeC, and the equilibrium elastic modulus of the said secondary resin layer is 0.23-0.80 GPa.   The optical fiber according to claim 1, wherein the primary resin layer comprises a cured product of a resin composition containing a urethane oligomer, a monomer, a photopolymerization initiator and a silane coupling agent.   The optical fiber according to claim 2, wherein the resin composition contains 0.5 to 1.5% by mass of a silane coupling agent.   The optical fiber according to claim 2 or 3, wherein the monomer comprises a polar monomer.

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