CN107474605B

CN107474605B - Doped coating layer material for optical fiber and preparation method thereof

Info

Publication number: CN107474605B
Application number: CN201710714180.3A
Authority: CN
Inventors: 周桂耀; 王腾; 夏长明; 侯峙云; 刘建涛; 张慧佳
Original assignee: Guangzhou Huarenyihe Specialty Fiber Technology Co ltd; South China Normal University
Current assignee: Guangzhou Huarenyihe Specialty Fiber Technology Co ltd; South China Normal University
Priority date: 2017-08-18
Filing date: 2017-08-18
Publication date: 2021-03-26
Anticipated expiration: 2037-08-18
Also published as: CN107474605A

Abstract

The invention relates to the technical field of photoelectric materials, and particularly discloses a doped coating layer material for an optical fiber, which comprises the following raw materials in parts by weight: multifunctional acrylate and doped whiskers; the multifunctional acrylate accounts for 90-99.9% by mass, and the doped whisker accounts for 0.1-10% by mass. Methods of making the material are also disclosed. The doped coating layer material for the optical fiber can effectively improve the heat insulation and ageing resistance of the optical fiber coating layer, simultaneously improve the photocuring speed of the ultraviolet-curing optical fiber coating layer paint, and has good bonding capability with quartz glass.

Description

Doped coating layer material for optical fiber and preparation method thereof

Technical Field

The invention relates to the technical field of photoelectric materials, in particular to an ultraviolet curing material containing a second phase or multiphase dopant and used for optical fiber coating and a preparation method thereof.

Background

Because the optical fiber has excellent transmission capability, anti-electromagnetic interference and other favorable performances, the optical fiber is widely applied to the fields of communication and sensing at present. With the development of communication and sensing technologies, higher requirements are put on the performance of optical fibers, and the optical fiber coating layer, as an important component of a conventional optical fiber, is also subject to further optimization and upgrading.

The optical fiber coating layer plays the roles of isolating the optical fiber from the environment and improving the mechanical property of the optical fiber, and further can keep the stability of the optical fiber property in long-distance transmission to a certain extent. Most of the current common commercial optical fibers adopt a double-coating layer structure design, and the first layer (inner layer) is a relatively soft and low-modulus buffer layer and mainly plays a role in reducing loss caused by a microbending effect; the second (outer) layer is typically a relatively tough, high modulus coating that serves to protect the optical fiber and enhance the mechanical properties of the optical fiber. At present, most of mainstream optical fiber coating coatings are multifunctional acrylate, the main difference between the first coating layer and the second coating layer is that partial components are different, and the main advantage is that the first coating layer and the second coating layer have good interlayer bonding force and cannot be easily separated in later-stage use.

The optical fiber used for communication and sensing has high sensitivity to temperature, the optical fiber coating layer also needs to have certain heat insulation performance, and when the use environment is special or severe, the reliability of the conventional polyacrylate coating layer is reduced, the performance of the optical fiber is poor, and even the phenomenon that the optical fiber cannot be used occurs. Therefore, on the premise of not changing the basic formula of the multifunctional acrylate, the method for improving the heat insulation performance of the optical fiber coating layer is worthy of attention.

The light-cured resin material used for traditional rapid prototyping has more limit requirements on doped reinforcing materials, and the reinforcing materials are expected to reduce the loss of light energy as much as possible, and simultaneously improve the penetration depth of light rays in a matrix as much as possible, and currently, glass fibers are mostly used as the reinforcing materials. Because the thickness of the optical fiber coating layer is extremely thin (mum magnitude), the optical fiber coating layer is insensitive to the penetration depth of light rays during photocuring, the shielding effect of the reinforcing material in the matrix on the light rays is relieved, the selection limit of the reinforcing material is relaxed, meanwhile, the reinforcing material in the matrix is used as a light ray scattering source, the propagation optical path of the light rays in the matrix can be effectively improved, and the addition of the reinforcing material with proper content for the optical fiber coating layer coating can improve the curing speed of the optical fiber coating layer coating and increase the utilization efficiency of the light rays.

At present, the optical fiber coating layer paint mainly comprises ultraviolet light curing type multifunctional acrylate, when ultraviolet light is used for curing the optical fiber coating layer paint, the ultraviolet absorption utilization rate is not enough, the ultraviolet curing efficiency and speed are reduced, and for high-speed wire drawing, under the condition that the original optical fiber coating layer paint formula is not changed, the ultraviolet radiation power needs to be increased so as to meet the optical fiber coating layer paint curing process requirement during the rapid wire drawing.

Therefore, it is an urgent need to select a better "scattering source" to reduce the ultraviolet radiation power, reduce the energy consumption and reduce the cost while ensuring the wire drawing speed.

Disclosure of Invention

In view of the above, it is desirable to provide a doped coating layer material for optical fiber and a method for preparing the same. The doped coating layer material for the optical fiber can effectively improve the heat insulation and ageing resistance of the optical fiber coating layer, improves the photocuring speed of the ultraviolet-curing optical fiber coating layer paint, and has good bonding capability with quartz glass.

In order to achieve the purpose, the invention adopts the following technical scheme:

the doped coating layer material for the optical fiber comprises the following raw materials: multifunctional acrylate and doped whiskers; the multifunctional acrylate accounts for 90-99.9% by mass, and the doped whisker accounts for 0.1-10% by mass.

Preferably, the multifunctional acrylate accounts for 94-99.9% by mass, and the doped whisker accounts for 0.1-6% by mass.

Further, the multifunctional acrylate is an ultraviolet curable resin.

Preferably, the multifunctional acrylate is oily colorless transparent liquid at room temperature, has good wettability with doped whiskers, and can be well adhered to quartz glass after ultraviolet curing of the whisker doped multifunctional acrylate coated on the quartz glass.

Further, the doped whisker includes, but is not limited to, one or more of potassium titanate whisker, calcium sulfate whisker, calcium carbonate whisker, silicon nitride whisker, aluminum borate whisker, zinc oxide whisker, carbon nanotube, carbon nanowire, graphene, poly (butyl acrylate-styrene) whisker, poly (4-hydroxybenzoates) whisker.

As some of these examples, the doping whiskers are potassium titanate whiskers.

Preferably, the potassium titanate whiskers have a diameter of 0.05 to 2 μm and a length of 3 to 100 μm, and are white powdery solids at room temperature.

More preferably, the potassium titanate whiskers have a diameter of 0.1 to 0.5 μm and a length of 3 to 15 μm.

Further, the mirror image single-side thickness of the optical fiber coating layer is 10-45 μm.

On the basis of the above, the doped coating layer material for optical fiber of the present invention may further comprise various additional additives, such as antioxidants, stabilizers, photoinitiators, adhesion promoters, etc., according to actual requirements, that is:

the doped coating layer material for the optical fiber comprises the following raw materials: multifunctional acrylate, doped whisker and additive; the multifunctional acrylate comprises (90-95.9%) by mass, the doped whisker comprises 0.1-6% by mass and the additive comprises 0-4% by mass.

Further, the additive comprises at least one of an antioxidant, a stabilizer, a photoinitiator and an adhesion promoter.

As some of these examples, the antioxidant is a bis-hindered thiophenol or thiodiethylene bis (3, 5-di-t-butyl) -4-hydroxyhydrocinnamate.

As some of these examples, the stabilizer is a tetrafunctional thiol, optionally pentaerythritol tetrakis (3-mercaptopropionate).

As some of these examples, the photoinitiator is N-p-methylbenzyl maleimide.

As some of these examples, the adhesion promoter is a poly (alkoxy) silane, most preferably bis (trimethoxysilylethyl) benzene.

A method of preparing a doped coating material for optical fibers, comprising:

step 1) taking dry whiskers, wherein the water content of the whiskers is less than or equal to 0.3%;

step 2) mixing the dried crystal whisker and the multifunctional acrylate at room temperature in a dark environment to finally obtain a doped mixture;

and 3) removing bubbles in the doping mixture obtained in the step 2) to obtain the doping coating layer material for the optical fiber.

Further, in order to obtain the whiskers in the step 1), one or more of direct heating drying under normal pressure, vacuum heating drying and vacuum (reduced pressure) drying can be adopted to remove water in the whiskers. The presence of moisture is particularly important in the performance of doped coating materials for optical fibers, so that during the preparation process of the present invention, the whisker is removed as much moisture as possible.

Further, in order to obtain the doped mixture in the step 2), the dry whiskers and the multifunctional acrylate are uniformly stirred in the same direction in the mixing and stirring process so as to improve the orientation consistency of the whiskers in the matrix.

As some of these examples, whiskers (e.g., potassium titanate whiskers) are subjected to a continuous treatment at a temperature in the range of 50-300 deg.C for 0.1-10 hours to remove adsorbed moisture from the whiskers.

Further, the method for removing the bubbles in the step 3) comprises one or more of standing, ultrasonic oscillation, vacuum pumping (decompression operation) or centrifugation. The whisker has larger specific surface area, can adsorb a certain amount of air on the surface thereof in the stirring and mixing process, and can introduce part of gas due to the mechanical stirring effect in the mixing process, so micron/submicron or even millimeter-sized bubbles are easy to appear in the mixture, and the mixture is milky. Therefore, it is also necessary to subject the resulting mixture to a defoaming treatment during the production process.

As some examples, the method for removing bubbles in step 3) includes performing ultrasonic oscillation treatment on the doped mixture, then placing the doped mixture in a shady, dry and dark place, continuously standing, and determining the corresponding standing time according to the amount of the mixed material to remove bubbles in the doped mixed material. If ultrasonic oscillation treatment is carried out for 0.1 to 10 hours, and standing is continuously carried out for 0.1 to 240 hours.

The doped coating layer materials for the optical fiber processed in the steps 1) to 3) are uniformly mixed, and bubbles are completely removed.

The doped coating layer material for the optical fiber is mainly applied to single-mode optical fibers, few-mode optical fibers or multi-mode optical fibers; the curing mode is one or more of ultraviolet curing and thermal curing, preferably ultraviolet curing, and the mirror image single-side thickness range of the optical fiber coating layer is 10-45 mu m.

The invention has the beneficial effects that:

the whisker doped ultraviolet light curing type optical fiber coating layer material can effectively improve the heat insulation performance of an optical fiber coating layer, and the heat insulation performance can be regulated and controlled by controlling the type and the content of the whisker doping according to actual requirements, so that the flexibility is stronger; meanwhile, the ultraviolet curing efficiency of the optical fiber coating layer coating can be improved, and compared with the multifunctional acrylate coating without introducing the doped crystal whiskers, the thermal stability of the optical fiber coating layer is not influenced by the introduction of the crystal whiskers.

The optical fiber coating layer paint is not only suitable for coating quartz optical fibers, but also suitable for coating polymer optical fibers or other optical fibers, has wide application range, and is preferably applied to coating the quartz optical fibers.

Drawings

FIG. 1 and FIG. 2 are graphs showing the results of heat-shielding performance tests using two spectrometers having different response bands, wherein the doped coating layer material for optical fibers has whisker doped content fractions of 0 wt%, 3 wt% and 5 wt%, respectively;

FIG. 3 is a graph showing the thermal stability test results of a doped coating material for optical fibers, which is selected to have whisker doped content fractions of 0% wt, 3% wt, and 5% wt, respectively;

fig. 4 is a schematic view of an experimental device for testing light curing efficiency.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be further clearly and completely described below with reference to the embodiments of the present invention. It should be noted that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The inorganic whisker material has high melting point, good heat resistance and flame retardant property. When inorganic whiskers are added to a resin, the strength of the resin is hardly lost at high temperatures, and even if the matrix is weak, the strength can be greatly improved at high temperatures due to the reinforcing effect of the whiskers. Due to the existence of the whisker, macromolecules in the resin or the rubber are not easy to slip, the glass transition temperature can be increased, and the heat resistance is inevitably improved. The potassium titanate whisker can resist a high-temperature environment of 1200 ℃, has high infrared reflectivity and low heat conduction efficiency, and has excellent performance when being used as a heat-insulating and flame-retardant material. Meanwhile, the crystal whisker is fine in structure and has excellent mechanical properties such as high strength and high modulus, and the crystal whisker can be uniformly dispersed when added into thermosetting or ultraviolet curing resin, can play a role in supporting a mechanical framework and form a polymer-fiber composite material, can be developed into an oriented structure in the presence of the crystal whisker, does not generate anisotropy, can reduce defect formation, and simultaneously effectively transfers stress and prevents crack propagation; besides the function of reducing the shrinkage rate of common inorganic filler, the added crystal whisker can generate certain deformation when the fibrous filler is stressed, so that the stress is easy to relax, the interface stress concentration effect and the participating stress are eliminated, and the internal stress of the product is reduced. The whiskers have the effect of increasing the cohesive strength of the polymer and reducing weak links, so that the mechanical strength can be obviously improved.

The whisker material and the multifunctional acrylate have good adhesion, and the whisker material can be effectively and uniformly dispersed in the multifunctional acrylate matrix due to the addition of the whisker material, can be used as a scattering source of light rays in the transparent multifunctional acrylate, further effectively increases the propagation optical path of ultraviolet rays in the multifunctional acrylate, further improves the absorption and utilization efficiency of the multifunctional acrylate to the ultraviolet rays, and can reduce the ultraviolet irradiation power, the energy consumption and the cost while ensuring the wire drawing speed.

The following examples illustrate the technical solution of the present invention in detail by taking potassium titanate whiskers as an example, and other types of whiskers included in the present invention also have the same performance effects, which are not listed here.

Example 1

1. Preparing and pretreating whisker-doped coating layer material raw materials for optical fibers:

taking 50g of potassium titanate whisker to carry out drying pretreatment at 120 ℃, wherein the drying time is 8 hours, and completely removing free water adsorbed by the potassium titanate whisker from the surrounding environment; 50g of multifunctional acrylate (model KG200 purchased from Shanghai Feikai photoelectric Material Co., Ltd.) was placed in a dry, shady and dark place for use.

2. Preparation of whisker-doped coating layer material for optical fiber:

respectively preparing a plurality of whisker doped optical fiber coating layer materials with potassium titanate whisker content of 0 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt% and 6 wt%, stirring and mixing potassium titanate whisker and multifunctional acrylate at room temperature in a dark environment, preferably stirring in a single direction, and stirring until the whisker doped optical fiber coating layer material is uniformly mixed.

In the stirring and mixing process, because the whisker has a large specific surface area, a certain amount of air can be adsorbed on the surface of the whisker, and part of gas can be mixed in the mechanical stirring process, micron/submicron or even millimeter-sized bubbles can easily appear in the mixture, so that the mixture is milky white, and the existence of the bubbles can generate irreversible influence on the quality of a later-stage optical fiber coating layer.

Therefore, after the mixing and stirring are finished, ultrasonic oscillation treatment is carried out for 2 hours, and then the mixture is placed in a cool, dry and dark place and continuously stands for 80 hours to remove bubbles in the mixture. Of course, in order to ensure the uniformity of the coating material of the prepared whisker doped optical fiber, the stirring and bubble removing operations can be circularly carried out for several times until a mixture which is uniformly doped and does not contain bubbles is obtained.

3. Testing the performance of the whisker doped coating layer material for the optical fiber:

for the quartz glass rod used for testing the aging properties, a surface pretreatment is required. Firstly, using ultrapure water to clean until water drops are not adhered to the surface of the glass rod, then using a piece of mirror wiping paper to wipe the glass rod, removing residual water on the surface, and keeping the glass rod in a cool and dry place for later use.

(1) Adhesion Property and aging test

Selecting a pretreated quartz glass rod with the diameter of 0.8mm as a substrate, respectively coating doping coating layer materials for ultraviolet curing optical fibers with different whisker doping weight percentages on the quartz glass rod by using a pulling method, curing the materials for the same time by using an ultraviolet lamp, placing the cured coating layer materials in a water bath at 80 ℃ after the coating layer materials are completely cured, recording and observing an experimental phenomenon every 24 hours, and obtaining the results shown in table 1 (the passing represents the qualified test, namely the passing means that the sample does not fall off, swell or have other obvious failure phenomena in the experimental test process):

TABLE 1

The experimental samples treated in the same way were subjected to dry heat treatment at 80 ℃ and observed every 24 hours, with the results shown in table 2:

TABLE 2

All samples in the above tables 1 and 2 do not fall off, swell or otherwise fail during the testing process, which shows that the prepared whisker-doped ultraviolet-curing optical fiber coating material has good binding force with the quartz glass matrix and good aging resistance.

(2) Testing of Heat insulating Properties

Radiation heat transfer is one of important heat transfer mechanisms, and how to effectively block heat radiation in a heat insulation material has important significance for improving the heat insulation performance of the material. As shown in fig. 1 and fig. 2, in this experiment, whisker-doped optical fiber coating materials with the same uv curing time and the same thickness and curing time were selected to perform a transmission spectrum test to show the insulation performance of the above ratio of the whisker-doped optical fiber coating material to radiation heat transfer, wherein the whisker-doped optical fiber coating materials have the same mass fraction of 0% wt, 3% wt, and 5% wt, respectively. Fig. 1 and 2 show the test results of two spectrometers with different response bands used in the experimental test.

The result analysis can show that the introduction of the whisker can effectively shield the electromagnetic wave from visible light to near infrared wave band and can effectively block the radiation heat transfer in the wave band range.

(3) Thermal stability test

As shown in fig. 3, the doped coating layer material for optical fiber, which is cured in the same uv curing time and contains 0 wt%, 3 wt% and 5 wt% of whisker doped substance, is selected, and subjected to thermogravimetric test analysis to test the thermal stability of the doped coating layer material, and from the results of the thermogravimetric test, it can be seen that the addition of a small amount of potassium titanate whiskers does not have an adverse effect on the thermal stability of the coating layer material for optical fiber.

(4) Photocuring efficiency test

The test of the light curing efficiency designed in the experiment is a comparative experiment, and only qualitative comparison is carried out on the light curing efficiency of the sample. Selecting isovolumetric samples with the whisker doping mass fractions of 0% wt, 3% wt and 5% wt respectively, dripping the isovolumetric samples onto a glass slide respectively, carrying out ultraviolet stroboscopic curing treatment on the 3 samples by using an ultraviolet lamp (the flash frequency of the ultraviolet lamp is 1Hz, the passage time is 0.5s), and recording the time for starting curing of each sample, wherein the experimental device is shown in FIG. 4.

Using an ultraviolet lamp with the same specification, carrying out stroboscopic curing treatment on samples with the whisker doping content of 0 wt%, 3 wt% and 5 wt% respectively, and obtaining the following results: for the optical fiber coating layer material with the whisker doping content of 0 wt%, when the stroboscopic frequency of an ultraviolet lamp is 1Hz, the coating begins to be cured after 7 s; for the optical fiber coating layer material with the whisker doping content of 3 wt%, when the stroboscopic frequency of an ultraviolet lamp is 1Hz, the coating begins to be cured after 4 s; for the optical fiber coating layer coating with the whisker doping content of 5 wt%, when the stroboscopic frequency of an ultraviolet lamp is 1Hz, the coating starts to be cured after 3 s. The comparison experiment shows that the introduction of the doped crystal whisker can effectively improve the ultraviolet light curing efficiency of the matrix material and improve the utilization rate of ultraviolet light.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A doped coating layer material for optical fibers is characterized by comprising the following raw materials: multifunctional acrylate and doped whiskers; the multifunctional acrylate is 90-99.9 wt%, the doped whisker is 0.1-10 wt%, the doped whisker is potassium titanate whisker, and the potassium titanate whisker has a diameter of 0.05-2 μm and a length of 3-100 μm; the multifunctional acrylate is ultraviolet light curing resin, and the multifunctional acrylate is oily colorless transparent liquid at room temperature.

2. The doped coating layer material for the optical fiber according to claim 1, further comprising an additive, wherein the mass percentage of the multifunctional acrylate is 90-95.9%, the mass percentage of the doped whisker is 0.1-6%, and the mass percentage of the additive is 0-4%.

3. The doped coating layer material for optical fibers according to claim 2, wherein the additive comprises at least one of an antioxidant, a photoinitiator, an adhesion promoter.

4. A method of preparing a doped coating layer material for optical fibers according to claim 1, comprising:

step 1) taking dry potassium titanate whiskers, wherein the water content of the whiskers is less than or equal to 0.3%, and the specifications of the potassium titanate whiskers are that the diameter is 0.05-2 mu m, and the length is 3-100 mu m;

step 2) mixing the dried crystal whisker and the multifunctional acrylate at room temperature in a dark environment to obtain a doped mixture;

and 3) removing bubbles from the doping mixture of the step 2) to obtain the doped coating layer material for the optical fiber according to claim 1.

5. The method for preparing a doped coating layer material for optical fibers according to claim 4, wherein the dry whiskers and the multifunctional acrylate are uniformly stirred in the same direction during the mixing and stirring process to obtain the doped mixture in the step 2) so as to improve the uniformity of the orientation of the whiskers in the matrix.

6. The method for preparing the doped coating layer material for optical fiber according to claim 4, wherein the whiskers in step 1) are obtained by removing water from the whiskers by one or more of direct atmospheric pressure heating and drying and vacuum heating; the drying temperature is 50-300 deg.C, and the drying time is 0.1-10 hr.

7. The method of claim 4, wherein the step 3) of removing bubbles comprises one or more of standing, ultrasonic vibration, vacuum pumping, and centrifugation.