A glass yarn gradient composite coating and a method for preparing the same

Abstract

The application provides a glass yarn gradient composite coating and a preparation method thereof; the preparation method comprises the following steps: surface treatment, directional adsorption, gradient polymerization, post-treatment, detection and winding; the gradient composite coating comprises, from inside to outside, an interface anchoring area with a thickness of 50-200 nm, which is chemically combined with the glass yarn matrix through M-O-Si covalent bond; a gradient transition area with a thickness of 1-3 microns, wherein the inorganic nanoparticle content is distributed in a gradient decreasing manner from inside to outside; and a surface functional area with a thickness of 2-5 microns, which is a layer of organic-inorganic hybrid material with high crosslinking density; the interface anchoring area, the gradient transition area and the surface functional area are integrated through the continuous gradient transition of composition and crosslinking density; the application can realize the chemical bonding between the coating and the yarn matrix, the integrated connection between layers, and the multifunctional composite to meet the application under harsh working conditions.

Description

Technical Field

[0001] This invention belongs to the field of glass fiber surface treatment technology, specifically relating to a glass yarn gradient composite coating and its preparation method. Background Technology

[0002] Existing glass yarn surface coating technologies mainly employ impregnation and curing processes. For example, Chinese patent application CN114700230A discloses a glass yarn curing coating device and process, which forms two cured coating layers on the glass yarn surface through two impregnations and two UV curings. This technology improves the smoothness and wear resistance of glass yarn to some extent, but still has shortcomings.

[0003] In the aforementioned technologies, the coatings primarily achieve bonding between the coating and the glass substrate through physical adsorption and mechanical interlocking. Due to the lack of chemical bonding, the interfacial bonding strength is limited, making it prone to interfacial delamination failure after long-term use. Furthermore, the distinct interfaces between multilayer coating structures easily become stress concentration points and crack propagation channels, leading to insufficient interlayer bonding and further exacerbating the risk of structural instability. In addition, wear-resistant fillers in the coatings are prone to agglomeration, resulting in poor coating performance stability and high manufacturing costs. Functionally, existing coatings only provide basic reinforcement and wear resistance, lacking a synergistic design for multiple properties such as high-temperature resistance, high-frequency vibration resistance, and fatigue resistance, making it difficult to meet the demands of complex applications under harsh working conditions.

[0004] Therefore, there is a need to design a glass yarn gradient composite coating and its preparation method that can achieve chemical bonding between the coating and the yarn matrix, integrated interlayer connection, and multifunctional composite to meet the application requirements under harsh working conditions, in order to solve the current technical problems. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a glass yarn gradient composite coating and its preparation method that enables chemical bonding between the coating and the yarn substrate, integrated interlayer connection, and multifunctional composite to meet the needs of applications under harsh working conditions.

[0006] The technical solution of this invention is: a method for preparing a glass yarn gradient composite coating, comprising the following steps: Surface treatment: Glass yarn is passed through the PECVD reaction chamber at a constant speed. Using organometallic compounds as precursors and oxygen as reactant, a metal oxide nanofilm is deposited on the surface of the glass yarn under the action of radio frequency plasma. Directional adsorption: The surface metallized glass yarn is passed through a treatment chamber with a high-frequency electric field applied, and a functional silane coupling agent is sprayed onto the yarn surface by electrostatic spraying, so that the coupling agent molecules are oriented and form covalent bonds with the metal oxide film. Gradient polymerization: Glass yarn that has undergone directional adsorption is passed through multiple independent reaction zones in series. Each reaction zone is sprayed with a polymerizable precursor solution with different inorganic nanoparticle contents. Combined with gradient temperature control and light control, an integrated coating with a gradient decreasing inorganic nanoparticle content is formed on the surface of the glass yarn. Post-treatment: The glass yarn after gradient polymerization is treated with supercritical carbon dioxide, and then the pressure is slowly released to eliminate residual internal stress in the coating. Inspection and winding: The glass yarn after post-processing is inspected online. If it passes the inspection, it is wound up under constant tension to obtain the final product.

[0007] Furthermore, in the surface treatment step, the organometallic compound precursor is one or more of trimethylaluminum, tetraisopropyl titanate, zirconium tetrachloride, and hexamethyldisilazane; The thickness of the metal oxide nanofilm is 10~50 nm.

[0008] Furthermore, in the directional adsorption step, the frequency of the high-frequency electric field is 1~10 MHz, and the field strength is 10~100V / cm; The silane coupling agent is selected from one or more of KH550, KH560, KH570, and A-171.

[0009] Furthermore, in the gradient polymerization step, the number of reaction zones in the plurality of independent reaction zones connected in series is 3 to 5, the temperature of each reaction zone is gradually increased from 60°C to 200°C, and the ultraviolet light intensity is gradually increased from 0 to 200 mW / cm². 2 ; The content of inorganic nanoparticles in the polymerizable precursor solution sprayed in each reaction zone decreases in a gradient. The content of inorganic nanoparticles in the foremost reaction zone is 20-30 wt%, while the content of inorganic nanoparticles in the last reaction zone is 5-10 wt%.

[0010] Furthermore, in the gradient polymerization step, the polymerizable precursor solution comprises a polymerizable organic monomer, functional nanoparticles, a photoinitiator, a thermal initiator, and a solvent. The polymerizable precursor solution in the final reaction zone also includes functional fillers selected according to the target function.

[0011] Furthermore, the functional filler includes one or more of the following: wear-resistant filler, high-temperature resistant filler, low-dielectric filler, hydrophobic filler, and conductive filler.

[0012] Furthermore, in the post-processing step, the process parameters for the supercritical carbon dioxide treatment are set as follows: Temperature 40~80℃, pressure 10~30MPa, processing time 30~120min; the depressurization rate of the slow depressurization is ≤0.5MPa / min.

[0013] Furthermore, in the step of detecting the winding process, the online detection includes: Infrared spectrometer used to monitor the chemical structure of glass yarn composite coating; Laser thickness gauges are used to monitor the uniformity of glass yarn composite coating thickness; and, Machine vision defect detectors are used to monitor the surface quality of glass yarn composite coatings.

[0014] Furthermore, in the surface treatment step, the process parameters of the PECVD reaction chamber are set as follows: Radio frequency power 100~500W, reaction pressure 10~100Pa, deposition temperature 80~120℃, deposition time 30~120 s; The moving speed of the glass yarn is 2~50m / min.

[0015] A gradient composite coating of glass yarn, prepared by any one of the above methods, characterized in that the gradient composite coating comprises, from the inside to the outside, the following components: The interface anchoring region, with a thickness of 50~200nm, is chemically bonded to the glass yarn matrix via MO-Si covalent bonds; A gradient transition region, 1–3 μm thick, in which the content of inorganic nanoparticles decreases gradually from the inside to the outside; and, The surface functional region, with a thickness of 2~5μm, is a layer of organic-inorganic hybrid material with high cross-linking density; The interface anchoring region, gradient transition region, and surface functional region achieve an integrated structure through a continuous gradient transition of composition and crosslinking density.

[0016] The beneficial effects of this invention are: (1) In this invention, electric field, thermal field and light field are used in combination to realize the in-situ construction and structural control of coating in stages during yarn movement. Compared with the simple superposition mode of existing impregnation and curing, the coating formation process is multi-dimensionally controllable. (2) By introducing metal oxide nanofilms and electric field-assisted oriented adsorption of coupling agents, high-density chemical anchoring of coupling agents on glass surfaces was achieved, and the interfacial bonding force was improved from physical adsorption to covalent bond level, resulting in a significant increase in bonding force. (3) By using the gradient polymerization technology of spraying different inorganic content slurries in different areas and combining thermal field and light field, an integrated coating with gradient change in crosslinking density and performance from the inside to the outside was realized, which completely eliminated the interlayer interface of multilayer coating and avoided the problem of interlayer peeling. (4) Introducing supercritical carbon dioxide fluid treatment into the post-treatment process of glass yarn coating, the high diffusivity and swelling properties of supercritical fluid are used to achieve the rearrangement of coating molecular chains and the elimination of residual stress, which greatly reduces internal stress and improves coating stability. Attached Figure Description

[0017] Figure 1 This is a flowchart of the preparation method of the glass yarn gradient composite coating in this invention. Detailed Implementation

[0018] Various exemplary embodiments of the invention will now be described in detail with reference to the accompanying drawings. The descriptions of the exemplary embodiments are merely illustrative and are in no way intended to limit the invention or its application or use. The invention can be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the invention thorough and complete, and to fully express the scope of the invention to those skilled in the art. It should be noted that, unless otherwise specifically stated, the relative arrangement of components and steps, the composition of materials, numerical expressions, and values ​​set forth in these embodiments should be interpreted as merely exemplary and not as limiting.

[0019] The terms "first," "second," and similar words used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different parts. Words such as "including" or "comprising" mean that the element preceding the word encompasses the element listed after it, without excluding the possibility of encompassing other elements. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0020] like Figure 1 As shown, a method for preparing a glass yarn gradient composite coating is disclosed, comprising the following steps: S1, Surface treatment: Glass yarn is passed through the PECVD reaction chamber at a constant speed. Using organometallic compounds as precursors and oxygen as reactant, a metal oxide nanofilm is deposited on the surface of the glass yarn under the action of radio frequency plasma. This film not only activates the glass surface, but also provides active sites for subsequent reaction with coupling agents. S2, Directional Adsorption: The surface-metallized glass yarn is passed through a treatment chamber with a high-frequency electric field applied, and a functional silane coupling agent is sprayed onto the yarn surface by electrostatic spraying, so that the coupling agent molecules are oriented and form covalent bonds with the metal oxide film. S3, gradient polymerization: Glass yarn that has undergone directional adsorption is passed through multiple independent reaction zones in series. Each reaction zone is sprayed with a polymerizable precursor solution with different inorganic nanoparticle contents. Combined with gradient temperature control and light control, an integrated coating with a gradient decreasing inorganic nanoparticle content is formed on the surface of the glass yarn. S4, Post-treatment: The glass yarn after the gradient polymerization step is treated with supercritical carbon dioxide, and then the pressure is slowly released to eliminate the residual internal stress of the coating. S5, Inspection and winding: The glass yarn after the post-processing steps is inspected online. If it passes the inspection, it is wound up under constant tension to obtain the final product.

[0021] In some embodiments, during the surface treatment step, the organometallic compound precursor is one or more of trimethylaluminum, tetraisopropyl titanate, zirconium tetrachloride, and hexamethyldisilazane; the organometallic compound precursors trimethylaluminum, tetraisopropyl titanate, zirconium tetrachloride, and hexamethyldisilazane correspond to Al2O3 film, TiO2 film, ZrO2 film, and SiO2-based film deposited on the glass yarn surface, respectively. To further improve weather resistance, the organometallic compound is preferably tetraisopropyl titanate, corresponding to the formation of a TiO2 film deposited on the glass yarn surface. The TiO2 film has photocatalytic activity, which can further improve the weather resistance of the coating.

[0022] In some embodiments, the deposition thickness of the metal oxide nanofilm is 10-50 nm; too thin a film is insufficient to provide enough active sites, while too thick a film may affect the flexibility of the yarn. Using hexamethyldisilazane to prepare a SiO2-based film can balance cost and performance, and the SiO2 film has a similar composition to the glass substrate, resulting in optimal interfacial compatibility.

[0023] In some embodiments, during the surface treatment step, the diameter of the selected glass yarn monofilament is 5~13 μm; the moving speed of the glass yarn is 2~50 m / min; and the process parameters of the PECVD reaction chamber are set as follows: RF power 100~500 W, reaction pressure 10~100 Pa, deposition temperature 80~120℃, deposition time 30~120s; In some embodiments, during the directional adsorption step, the frequency of the high-frequency electric field is 1~10 MHz and the field strength is 10~100 V / cm; The silane coupling agent is selected from one or more of KH550, KH560, KH570, and A-171; the spraying flow rate of the silane coupling agent is 0.5~2 mL / min. Under the action of an electric field, the coupling agent molecules align themselves, with their polar heads facing the metal oxide surface and rapidly undergoing a condensation reaction to form MO-Si covalent bonds, while the functional groups at the other end align outwards, providing reaction sites for subsequent polymerization. Compared with the traditional impregnation method, the electric field-assisted method significantly increases the grafting density of the coupling agent and improves the interfacial bonding strength.

[0024] In some embodiments, in the gradient polymerization step, the number of reaction zones in the multiple independent reaction zones connected in series is 3 to 5. The temperature and ultraviolet light intensity of each reaction zone are independently controllable, and each reaction zone is equipped with an independent precursor solution spraying system. The temperature of each reaction zone is gradually increased from 60°C to 200°C, and the ultraviolet light intensity is gradually increased from 0 to 200 mW / cm². 2 The content of inorganic nanoparticles in the polymerizable precursor solution sprayed in each reaction zone decreases in a gradient. The content of inorganic nanoparticles in the foremost reaction zone is 20-30 wt%, while the content of inorganic nanoparticles in the last reaction zone is 5-10 wt%.

[0025] In some embodiments, during the gradient polymerization step, the polymerizable precursor solution comprises a polymerizable organic monomer, functional nanoparticles, a photoinitiator, a thermal initiator, and a solvent; wherein the polymerizable precursor solution in the final reaction zone further comprises a functional filler selected according to the target function.

[0026] As some more specific alternative examples, four independent reaction zones are connected in series, referred to in sequence as the first reaction zone, the second reaction zone, the third reaction zone, and the fourth reaction zone.

[0027] The temperature of the first reaction zone is set to 60-80℃, the ultraviolet light intensity is set to 0, and the precursor spraying flow rate is set to 1.5-2.5 mL / min. The precursor solution is prepared by mass of the following components: 30-50 parts polymerizable organic monomer, 20-30 parts functional nanoparticles, 1-5 parts photoinitiator, 1-5 parts thermal initiator, 0.5-2 parts rheology modifier, and 20-50 parts solvent. The function of the first reaction zone is to evaporate the solvent, initiate the initial polymerization through thermal initiation, and form the underlying inorganic-rich zone.

[0028] The temperature of the second reaction zone was set to 100~120℃, and the ultraviolet light intensity was set to 30~60 mW / cm². 2The precursor spraying flow rate is set to 1.0~1.5 mL / min; the precursor solution is prepared by mass of the following components: 30~50 parts polymerizable organic monomer, 10~20 parts functional nanoparticles, 1~5 parts photoinitiator, 1~5 parts thermal initiator, 0.5~2 parts rheology modifier, and 20~50 parts solvent. The second reaction zone serves to facilitate both thermal and photoinitiation, accelerating polymerization and causing the inorganic content to begin to decrease.

[0029] The temperature of the third reaction zone was set to 140~160℃, and the ultraviolet light intensity was set to 80~120 mW / cm². 2 The precursor spraying flow rate is set to 0.5~1.0 mL / min; the precursor solution is prepared by mass of the following components: 30~50 parts polymerizable organic monomer, 5~10 parts functional nanoparticles, 1~5 parts photoinitiator, 1~5 parts thermal initiator, 0.5~2 parts rheology modifier, and 20~50 parts solvent. The third reaction zone is dominated by photoinitiation, increases crosslinking density, and forms a transition layer.

[0030] The temperature of the fourth reaction zone was set to 180~200℃, and the ultraviolet light intensity was set to 150~200 mW / cm². 2 The precursor spraying flow rate is set to 0.5~1.0 mL / min; the precursor solution is prepared by mass of the following components: 30~50 parts polymerizable organic monomer, 10~30 parts functional nanoparticles, 1~5 parts photoinitiator, 1~5 parts thermal initiator, 0.5~2 parts rheology modifier, and 20~50 parts solvent. Different functional fillers and their proportions are selected according to the target function. The function of the fourth reaction zone is to deeply cure the substrate, forming a high cross-linking density layer on the surface to impart the desired function.

[0031] Gradient polymerization eliminates the physical interface between traditional multilayer coatings, avoids interlayer delamination, and solves the contradiction that a single material cannot simultaneously achieve both adhesion and surface hardness. At the same time, the combined effect of thermal and light fields ensures complete curing of the coating from the inside out, resulting in a composite coating with advantages such as integration, low stress, and high performance.

[0032] Specifically, polymerizable organic monomers can be selected from acrylates, epoxy resins, vinyl groups, etc.; among which acrylates include MMA, BA, TMPTA, TPGDA, HDDA, etc.; epoxy resins include bisphenol A epoxy resin and alicyclic epoxy resin; vinyl groups include styrene, NVP, etc. Functional nanoparticles can be selected from SiO2, TiO2, Al2O3, etc. Photoinitiators can be selected from 184, TPO, 1173, 819, etc. Thermal initiators can be selected from AIBN, BPO, V-40, etc. Rheology modifiers can be selected from fumed silica R972, BYK-410, polyamide wax, etc. Solvents can be selected from low-boiling-point solvents such as acetone, ethyl acetate, etc.

[0033] As an example, the polymerizable organic monomers are epoxy acrylate and TPGDA, with an epoxy acrylate to TPGDA mass ratio of 8:3; the functional nanoparticles are Al2O3; the photoinitiators are 1173 and 819, with a 1173 to 819 mass ratio of 4:1; the thermal initiator is BPO; the rheology modifier is BYK-410; and the solvent is acetone.

[0034] As another example, the polymerizable organic monomers are TMPTA and HDDA, with a mass ratio of TMPTA to HDDA of 3:2; the functional nanoparticles are SiO2; the photoinitiator is 184 and TPO, with a mass ratio of 184 to TPO of 3:1; the thermal initiator is AIBN; the rheology modifier is fumed silica R972; and the solvent is ethyl acetate.

[0035] As another example, the polymerizable organic monomers are MMA, BA, and KH570, with a mass ratio of MMA, BA, and KH570 of 5:3:1; the functional nanoparticles are hexagonal boron nitride; the photoinitiator is 184 and TPO, with a mass ratio of 184 to TPO of 3:2; the thermal initiator is V-40; the rheology modifier is polyamide wax; and the solvent is methyl ethyl ketone (MEK).

[0036] In some embodiments, the functional filler includes one or more of the following: wear-resistant filler, high-temperature resistant filler, low-dielectric filler, hydrophobic filler, and conductive filler. Specifically, the wear-resistant filler may be nano-ZrO2 or SiC, with an addition amount of 15-25 parts; the high-temperature resistant filler may be SiO2 or Al2O3, with an addition amount of 20-25 parts; the low-dielectric filler may be hexagonal boron nitride or polytetrafluoroethylene micro powder, with an addition amount of 10-20 parts; the hydrophobic filler may be modified silica or polytetrafluoroethylene micro powder, with an addition amount of 10-20 parts; and the conductive filler may be ITO, ATO, or graphene, with an addition amount of 5-15 parts.

[0037] In some embodiments, the process parameters for supercritical carbon dioxide treatment in the post-processing step are set as follows: Temperature 40~80℃, pressure 10~30 MPa, processing time 30~120 min; depressurization rate ≤0.5MPa / min for slow depressurization.

[0038] Supercritical carbon dioxide possesses liquid-like density and gas-like diffusivity, enabling it to penetrate the polymer network of the coating, swell the molecular chains, and promote the release of residual stress. It can also carry small amounts of functional monomers or crosslinking agents to achieve post-crosslinking or surface modification. A slow depressurization process is employed after treatment to prevent blistering or cracking of the coating due to rapid carbon dioxide escape, thus improving structural stability.

[0039] In some embodiments, the online detection step in the roll-up detection includes: Infrared spectrometer used to monitor the chemical structure of glass yarn composite coating; Laser thickness gauges are used to monitor the uniformity of glass yarn composite coating thickness; and, Machine vision defect detectors are used to monitor the surface quality of glass yarn composite coatings.

[0040] In some embodiments, a glass yarn gradient composite coating is disclosed, which is prepared by the preparation method in any of the above embodiments. The gradient composite coating comprises, from the inside to the outside, the following components: The interface anchoring region, with a thickness of 50~200 nm, is chemically bonded to the glass yarn matrix through MO-Si covalent bonds; A gradient transition region, 1–3 μm thick, in which the content of inorganic nanoparticles decreases gradually from the inside to the outside; and, The surface functional region, with a thickness of 2~5 μm, is a layer of organic-inorganic hybrid material with high cross-linking density; An integrated structure is achieved through a continuous gradient transition of composition and crosslinking density between the interface anchoring region, gradient transition region, and surface functional region.

[0041] The above embodiments utilize the combined use of electric, thermal, and optical fields to achieve in-situ construction and structural control of the coating in stages during yarn movement. Compared with the simple superposition mode of existing impregnation and curing, this achieves multi-dimensional controllability of the coating formation process. By introducing metal oxide nanofilms and using electric field-assisted coupling agent orientation adsorption, high-density chemical anchoring of the coupling agent on the glass surface is achieved, and the interfacial bonding force is improved from physical adsorption to covalent bonding, resulting in a significant increase in bonding strength. By using gradient polymerization technology that combines spraying different inorganic content slurries with thermal and optical fields, an integrated coating with gradient changes in crosslinking density and properties from the inside out is achieved, completely eliminating the interlayer interface of multilayer coatings and avoiding interlayer delamination problems. The introduction of supercritical carbon dioxide fluid treatment into the glass yarn coating post-treatment process utilizes the high diffusivity and swelling properties of supercritical fluid to achieve rearrangement of coating molecular chains and elimination of residual stress, significantly reducing internal stress and improving coating stability.

[0042] The various embodiments of the present invention have now been described in detail. To avoid obscuring the concept of the invention, some details known in the art have not been described. Those skilled in the art will fully understand how to implement the technical solutions disclosed herein based on the above description.

[0043] The embodiments described above only illustrate some implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A method for preparing a glass yarn gradient composite coating, characterized in that, Includes the following steps: Surface treatment: Glass yarn is passed through the PECVD reaction chamber at a constant speed. Using organometallic compounds as precursors and oxygen as reactant, a metal oxide nanofilm is deposited on the surface of the glass yarn under the action of radio frequency plasma. Directional adsorption: The surface metallized glass yarn is passed through a treatment chamber with a high-frequency electric field applied, and a functional silane coupling agent is sprayed onto the yarn surface by electrostatic spraying, so that the coupling agent molecules are oriented and form covalent bonds with the metal oxide film. Gradient polymerization: Glass yarn that has undergone directional adsorption is passed through multiple independent reaction zones in series. Each reaction zone is sprayed with a polymerizable precursor solution with different inorganic nanoparticle contents. Combined with gradient temperature control and light control, an integrated coating with a gradient decreasing inorganic nanoparticle content is formed on the surface of the glass yarn. Post-treatment: The glass yarn after gradient polymerization is treated with supercritical carbon dioxide, and then the pressure is slowly released to eliminate residual internal stress in the coating. Inspection and winding: The glass yarn after post-processing is inspected online. If it passes the inspection, it is wound up under constant tension to obtain the final product.

2. The method for preparing the glass yarn gradient composite coating according to claim 1, characterized in that: In the surface treatment step, the organometallic precursor is one or more of trimethylaluminum, tetraisopropyl titanate, zirconium tetrachloride, and hexamethyldisilazane. The thickness of the metal oxide nanofilm is 10~50 nm.

3. The method for preparing the glass yarn gradient composite coating according to claim 1, characterized in that: In the directional adsorption step, the frequency of the high-frequency electric field is 1~10MHz and the field strength is 10~100V / cm; The silane coupling agent is selected from one or more of KH550, KH560, KH570, and A-171.

4. The method for preparing the glass yarn gradient composite coating according to claim 1, characterized in that: In the gradient polymerization step, the number of reaction zones in the plurality of independent reaction zones connected in series is 3 to 5, the temperature of each reaction zone is gradually increased from 60°C to 200°C, and the ultraviolet light intensity is gradually increased from 0 to 200 mW / cm². 2 ; The content of inorganic nanoparticles in the polymerizable precursor solution sprayed in each reaction zone decreases in a gradient. The content of inorganic nanoparticles in the foremost reaction zone is 20-30 wt%, while the content of inorganic nanoparticles in the last reaction zone is 5-10 wt%.

5. The method for preparing the glass yarn gradient composite coating according to claim 4, characterized in that: In the gradient polymerization step, the polymerizable precursor solution comprises polymerizable organic monomers, functional nanoparticles, photoinitiators, thermal initiators, and solvents. The polymerizable precursor solution in the final reaction zone also includes functional fillers selected according to the target function.

6. The method for preparing the glass yarn gradient composite coating according to claim 5, characterized in that: The functional fillers include one or more of the following: wear-resistant fillers, high-temperature resistant fillers, low-dielectric fillers, hydrophobic fillers, and conductive fillers.

7. The method for preparing the glass yarn gradient composite coating according to claim 1, characterized in that: In the post-processing step, the process parameters for the supercritical carbon dioxide treatment are set as follows: Temperature 40~80℃, pressure 10~30MPa, processing time 30~120min; the depressurization rate of the slow depressurization is ≤0.5MPa / min.

8. The method for preparing the glass yarn gradient composite coating according to claim 1, characterized in that: In the aforementioned detection and winding step, the online detection includes: Infrared spectrometer used to monitor the chemical structure of glass yarn composite coating; Laser thickness gauges are used to monitor the uniformity of glass yarn composite coating thickness; and, Machine vision defect detectors are used to monitor the surface quality of glass yarn composite coatings.

9. The method for preparing the glass yarn gradient composite coating according to claim 1, characterized in that: In the surface treatment step, the process parameters of the PECVD reaction chamber are set as follows: RF power 100~500 W, reaction pressure 10~100 Pa, deposition temperature 80~120℃, deposition time 30~120s; The moving speed of the glass yarn is 2~50m / min.

10. A glass yarn gradient composite coating, prepared by the method according to any one of claims 1 to 9, characterized in that, The gradient composite coating comprises, from the inside out, the following: The interface anchoring region, with a thickness of 50~200nm, is chemically bonded to the glass yarn matrix via MO-Si covalent bonds; A gradient transition region, 1–3 μm thick, in which the content of inorganic nanoparticles decreases gradually from the inside to the outside; and, The surface functional region, with a thickness of 2~5μm, is a layer of organic-inorganic hybrid material with high cross-linking density; The interface anchoring region, gradient transition region, and surface functional region achieve an integrated structure through a continuous gradient transition of composition and crosslinking density.

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