Optical fiber inner layer resin with low refractive index and high-temperature and high-humidity environment resistance and preparation method thereof

Abstract

The invention discloses optical fiber inner layer resin with low refractive index and high-temperature and high-humidity environment resistance, which is prepared from a fluorine-containing siloxane oligomer, fluorosilane, water, hydrochloric acid and a photoinitiator, wherein the fluorine-containing siloxane oligomer is prepared from a fluorine monomer containing a carbon-carbon double bond, a silane coupling agent containing a carbon-carbon double bond, an acrylic monomer containing a hydroxyl group, isocyano ethyl methacrylate, a solvent, an initiator, a molecular weight regulator and DBTDL, and the prepared resin has good high temperature resistance and boiling resistance, can resist high-pressure boiling at 120 DEG C for 72 hours, and can be used as a high-temperature-resistant coating. The resin can meet the requirement that the long-term use performance at high temperature is not weakened, the resin has good elasticity modulus, moderate peel strength and low refractive index, and the refractive index nD20 is equal to 1.350-1.360.

Description

Technical Field

[0001] This invention belongs to the field of fine chemical coating materials and application technology, specifically relating to a low-refractive-index optical fiber inner layer resin resistant to high temperature and high humidity environments and its preparation method. Background Technology

[0002] Currently, the most widely used low-refractive-index UV-curable coatings in industry are fluorinated acrylate formulations. These formulations consist of fluorinated acrylate prepolymers, acrylate monomers, photoinitiators, and other additives. However, if operated for extended periods at temperatures above 85°C, ordinary acrylic resins undergo thermal aging and thermo-oxidative aging. Furthermore, organic coatings at high temperatures generate hydrogen gas, which has a stress-corrosion effect on quartz optical fibers, accelerating the fiber fatigue process and leading to fiber failure. To ensure normal operation of optical fiber communication under harsh conditions, the optical fiber, especially its coating, needs to withstand the test of high temperatures and other harsh environments, enabling stable transmission of optical signals. For example, patent CN2024106686452.3 describes a low-shrinkage, high-temperature-resistant inorganic-organic hybrid material for low-refractive-index optical fiber resin, prepared primarily from modified hydroxyl aluminum fluoride inorganic nanoparticles and fluorinated end-thiol hyperbranched acrylate. After doping and blending this material with the inner layer resin of the power transmission optical fiber and curing, it can effectively reduce the shrinkage rate of the inner layer coating and enhance the coating's temperature resistance and strength. Based on its mature equipment manufacturing and fiber drawing technology, Yangtze Optical Fibre and Cable (YOFC) has, through years of exploration and improvement, finally achieved the preparation of this type of fiber drawing tower and the confirmation of the fiber drawing process. It has successfully developed high-temperature resistant optical fiber (also known as PI fiber) with optimized polyimide coating, which has a long-term operating temperature of 300℃ and can withstand high pressure and chemical corrosion.

[0003] Common resin types for existing low-refractive-index optical fiber coatings mainly include: 1. Fluorinated acrylates: Although the refractive index is reduced by introducing fluorine atoms, precisely controlling the refractive index to a specific value remains challenging, requiring complex synthesis processes and precise formulation design. Furthermore, some fluorinated acrylate coatings have low tensile strength and elongation at break, making it difficult to meet the mechanical performance requirements of optical fibers during processing and use. 2. Fluorinated polyurethane acrylate resins: It is difficult to simultaneously meet the requirements of high tensile strength and high elongation at break, and the synthesis of fluorinated polyurethane acrylate resins involves raw materials such as polyisocyanates and fluorinated polyols, resulting in relatively high production costs. 3. Silane-modified acrylate resins: Under high temperature and high humidity environments, the performance stability of silane-modified acrylate resins is poor, and problems such as yellowing and decreased light transmittance may occur. Summary of the Invention

[0004] The purpose of this invention is to prepare a low-refractive-index optical fiber inner layer resin that is resistant to high temperature and high humidity environments. After curing, the coating has good elastic modulus and moderate peel strength, and can withstand high pressure boiling at 120℃ for 72 hours.

[0005] The low-refractive-index optical fiber inner layer resin resistant to high temperature and high humidity environments of this invention consists of the following components by mass ratio:

[0006]

[0007] Fluorosiloxane is selected from one or more of heptadecafluorodecyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltriethoxysilane, and nonafluorohexyltriethoxysilane.

[0008] The water is prepared from deionized water.

[0009] The hydrochloric acid is a 37% concentrated hydrochloric acid.

[0010] The photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenylpropanone (1173), phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (819), 2,4,6-trimethylbenzoyl-diphenylphosphine oxide (TPO), and tetramethylmichophenone (MK).

[0011] The content of each component in the fluorosiloxane oligomer and its preparation method:

[0012]

[0013] The fluorine monomer containing carbon-carbon double bonds is selected from one or more of the following: trifluoroethyl acrylate, perfluorooctyl acrylate, tridecylfluorooctyl methacrylate, tridecylfluorooctyl acrylate, dodecylfluoroheptyl acrylate, and dodecylfluoroheptyl methacrylate.

[0014] The carbon-carbon double bond-containing silane coupling agent is selected from one or more of the following: 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-acryloxypropyltrimethoxysilane.

[0015] The hydroxyl-containing acrylic monomer is selected from one of hydroxyethyl acrylate and hydroxypropyl acrylate.

[0016] The solvent is one or more of toluene, xylene, trimethylbenzene, butyl acetate, and n-hexane.

[0017] The initiator is selected from the following: benzoyl peroxide (BPO), lauroyl peroxide (LPO), tert-butyl hydroperoxide (TBHP), azobisisobutyronitrile (AIBN), and azobisisoheptanenitrile (ABVN).

[0018] The molecular weight regulator is selected from one of the following: dodecyl mercaptan, tert-dodecyl mercaptan, isooctyl 3-mercaptopropionate, and tert-butyl peroxide.

[0019] A second aspect of the present invention provides a method for preparing the above-mentioned low-refractive-index optical fiber inner layer resin resistant to high temperature and high humidity environments, comprising the following steps:

[0020] 1) Preparation method of the fluorosiloxane oligomer: 10% of a fluorine monomer containing carbon-carbon double bonds, a silane coupling agent containing carbon-carbon double bonds, a hydroxyl-containing acrylic monomer, and 70% of a solvent are mixed and added to a reaction flask. The mixture is stirred and heated to reflux for 30 minutes. Then, the remaining fluorine monomer containing carbon-carbon double bonds, the silane coupling agent containing carbon-carbon double bonds, the hydroxyl-containing acrylic monomer, the solvent, and all initiators and molecular weight regulators are added dropwise at a rate of 2 drops / second. After the addition is complete, the mixture is kept at the same temperature for 3 hours. The temperature is then lowered to 60°C, and ethyl isocyanate methacrylate and DBTDL are added. The mixture is kept at the same temperature for 4 hours. After cooling, the solvent in the system is removed using a vacuum pump to obtain the fluorosiloxane oligomer. The chemical reaction formula of the fluorosiloxane oligomer structure (taking Example 1 as an example) is as follows:

[0021]

[0022] 2) The method for preparing the UV-cured loose tube cladding material for optical fibers is as follows:

[0023] The method for preparing the refractive index-resistant fiber inner layer resin in high temperature and high humidity environments is as follows: fluorinated siloxane oligomers and fluorosilanes are added to a reaction flask and stirred. A mixture of water and hydrochloric acid is added dropwise at a rate of 1 drop / second. After the addition is complete, the mixture is stirred continuously for 1 hour, then heated and refluxed for 3 hours. After cooling, the solvent in the system is completely removed using a vacuum pump. A photoinitiator is then added to obtain the low refractive index fiber inner layer resin resistant to high temperature and high humidity environments.

[0024] Beneficial effects

[0025] This invention prepares a low-refractive-index optical fiber inner layer resin resistant to high temperature and high humidity environments through the combined action of the above-mentioned raw materials and a specific preparation method. This resin, as an inner coating for optical fibers, has the following innovative points and advantages:

[0026] 1) The resin prepared by this invention has a low refractive index.

[0027] 2) The resin prepared by this invention has both good elastic modulus and moderate peel strength;

[0028] 3) The resin prepared by this invention has both good high temperature resistance and water boiling resistance. It can withstand boiling in water at 120°C for 72 hours under high pressure, and its performance can be maintained for long-term use at high temperature without weakening. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] Example 1

[0031] Add 5g of perfluorooctylhexene, 0.7g of 3-methacryloyloxypropyltrimethoxysilane, 0.6g of hydroxypropyl acrylate, and 21g of xylene to a reaction flask, stir and heat to reflux for 30 minutes. Then, add the remaining 45g of perfluorooctylhexene, 6.3g of 3-methacryloyloxypropyltrimethoxysilane, 5.4g of hydroxypropyl acrylate, 9g of xylene, 2g of BPO, and 0.9g of dodecyl mercaptan dropwise at a rate of 2 drops / second. After the addition is complete, maintain the reaction temperature for 3 hours. Cool down to 60°C, add 4g of isocyanate methacrylate and 0.05g of DBTDL, and continue to maintain the reaction temperature for 4 hours. After cooling, remove 30g of xylene using a vacuum pump to obtain the fluorosiloxane oligomer FS-1.

[0032] Example 2

[0033] Add 44g of FS-1 and 36g of heptadecafluorodecyltriethoxysilane to a reaction flask and stir. Add a mixture of 20g of water and 0.2g of hydrochloric acid dropwise at a rate of 1 drop / second. After the addition is complete, stir continuously for 1 hour, then heat to 78℃ and reflux for 3 hours. After cooling, use a vacuum pump to remove all the solvent generated in the reaction. Add 1.8g of 1173 to obtain the low refractive index fiber inner layer resin 1, which is resistant to high temperature and high humidity environments.

[0034] Example 3

[0035] Add 50g of FS-1 and 30g of tridecafluorooctyltriethoxysilane to a reaction flask and stir. Add a mixture of 18g of water and 0.2g of hydrochloric acid dropwise at a rate of 1 drop / second. After the addition is complete, stir continuously for 1 hour, then heat to 78℃ and reflux for 3 hours. After cooling, use a vacuum pump to remove all the solvent generated in the reaction. Add 1.8g of 1173 to obtain low refractive index fiber inner layer resin 2 that is resistant to high temperature and high humidity environments.

[0036] Example 4

[0037] Add 54g of FS-1 and 28g of tridecafluorooctyltriethoxysilane to a reaction flask and stir. Add a mixture of 16g ​​of water and 0.2g of hydrochloric acid dropwise at a rate of 1 drop / second. After the addition is complete, stir continuously for 1 hour, then heat to 78℃ and reflux for 3 hours. After cooling, use a vacuum pump to remove all the solvent generated in the reaction. Add 2.2g of 1173 to obtain the low refractive index fiber inner layer resin 3, which is resistant to high temperature and high humidity environments.

[0038] Performance Testing: The performance of the prepared low-refractive-index fiber inner layer resins 1, 2, and 3 (resistant to high temperature and humidity environments) was compared with that of commercially available PC-373 fiber inner layer coating. The test results are shown in Table 1 below.

[0039] Table 1 Performance Test Results

[0040]

[0041]

[0042] This disclosure has been described with reference to the foregoing embodiments; however, these embodiments are merely examples for implementing this disclosure. It must be noted that the disclosed embodiments do not limit the scope of this disclosure. On the contrary, any changes and modifications made without departing from the spirit and scope of this disclosure are within the scope of patent protection of this disclosure.

Claims

1. A low-refractive-index optical fiber inner layer resin resistant to high temperature and high humidity environments, characterized in that: By mass ratio, it consists of the following components:

2. The low refractive index optical fiber inner layer resin resistant to high temperature and high humidity environments according to claim 1, characterized in that: The fluorinated siloxane oligomer, by mass ratio, consists of the following components:

3. The low refractive index optical fiber inner layer resin resistant to high temperature and high humidity environments according to claim 2, characterized in that: The fluorine monomer containing carbon-carbon double bonds is one or more of trifluoroethyl acrylate, perfluorooctyl acrylate, tridecafluorooctyl methacrylate, tridecafluorooctyl acrylate, dodecafluoroheptyl acrylate, and dodecafluoroheptyl methacrylate.

4. The low refractive index optical fiber inner layer resin resistant to high temperature and high humidity environments according to claim 2, characterized in that: The carbon-carbon double bond-containing silane coupling agent is one or more of 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and 3-acryloxypropyltrimethoxysilane.

5. The low refractive index optical fiber inner layer resin resistant to high temperature and high humidity environments according to claim 2, characterized in that: The hydroxyl-containing acrylic monomer is either hydroxyethyl acrylate or hydroxypropyl acrylate.

6. The low refractive index optical fiber inner layer resin resistant to high temperature and high humidity environments according to claim 2, characterized in that: The solvent is one or more of toluene, xylene, trimethylbenzene, butyl acetate, and n-hexane; the initiator is one or more of benzoyl peroxide, dilauryl peroxide, tert-butyl hydroperoxide, azobisisobutyronitrile, and azobisisoheptanenitrile; and the molecular weight regulator is any one of dodecyl mercaptan, tert-dodecyl mercaptan, isooctyl 3-mercaptopropionate, and tert-butyl peroxide.

7. The low refractive index optical fiber inner layer resin resistant to high temperature and high humidity environments according to claim 1, characterized in that: The fluorosilane is one or more of heptadecafluorodecyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, tridecafluorooctyltriethoxysilane, and nonafluorohexyltriethoxysilane.

8. The low refractive index optical fiber inner layer resin resistant to high temperature and high humidity environments according to claim 1, characterized in that: The hydrochloric acid is 37% concentrated hydrochloric acid; the photoinitiator is one or more of 2-hydroxy-2-methyl-1-phenylpropanone, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and tetramethylmichophenone; the water is deionized water.

9. A method for preparing the low-refractive-index, high-temperature and high-humidity resistant optical fiber inner layer resin according to any one of claims 1-8, characterized in that, The following steps are involved: 1) Mix 10% of the carbon-carbon double bond fluorine monomer, carbon-carbon double bond silane coupling agent, hydroxyl-containing acrylic monomer and 70% of the solvent in a reaction flask, stir and heat to reflux and keep warm for 30 min. Then add the remaining carbon-carbon double bond fluorine monomer, carbon-carbon double bond silane coupling agent, hydroxyl-containing acrylic monomer and solvent, as well as all initiators and molecular weight regulators dropwise, controlling the drop rate to 2 drops / second. After the drop is completed, keep the reaction at the whole temperature for 3 h, cool down to 60℃, add isocyanate methacrylate and DBTDL, and keep the reaction at the temperature for 4 h. After cooling, use a vacuum pump to remove the solvent from the system to obtain the fluorinated siloxane oligomer. 2) Add the fluorosiloxane oligomer and fluorosilane to the reaction flask according to the formula and stir. Add a mixture of water and hydrochloric acid at a rate of 1 drop / second. After the addition is complete, stir continuously for 1 hour and then heat and reflux for 3 hours. After cooling, use a vacuum pump to remove all the solvent from the system. Add a photoinitiator to obtain the low refractive index fiber inner layer resin that is resistant to high temperature and high humidity environments.

Images