Preparation method of high-definition electronic screen protection paper

Abstract

The invention relates to the technical field of papermaking, in particular to a preparation method of high-definition electronic screen protection paper. According to the method, regenerated cellulose fibers serve as main raw materials, functional composite fibers of a core-shell structure are constructed, a core layer is the regenerated cellulose fibers, a shell layer is a polypyrrole / graphene composite conductive layer, and the lasting antistatic performance is achieved; meanwhile, the surface-modified nano silicon dioxide aerogel particles are introduced, so that the optical performance and the mechanical strength are improved; then compounding with polyimide fibers modified by a silane coupling agent, adding a bio-based wet strength agent and a fluorocarbon defoaming agent, and carrying out the steps of plasma pretreatment, pulping, on-net papermaking, controllable drying, magnetron sputtering surface treatment and the like to prepare the protective paper. The obtained protective paper has the characteristics of being ultrathin, high in strength, high in light transmittance, lasting in antistatic property and the like, and is suitable for protection of high-end liquid crystal display screens and OLED screens.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of papermaking, in particular to a preparation method of high-definition electronic screen protection paper. BACKGROUND

[0002] High-definition electronic screens, such as liquid crystal display (LCD) and organic light-emitting diode (OLED) screens, as the core components of modern electronic devices, are extremely susceptible to scratches, abrasions and electrostatic dust adsorption on the surface during production and transportation, resulting in a decrease in product yield. Traditional protection paper is mostly made of natural fibers such as wood pulp and hemp pulp as raw materials, prepared by physical mixing and conventional processes, which has a certain protective effect, but has obvious shortcomings in thickness, cleanliness, optical performance and antistatic stability. For example, Chinese invention patent CN112593453A (a manufacturing method of liquid crystal substrate protection paper) discloses a protection paper preparation method using bleached kraft softwood pulp and bleached hemp pulp as raw materials. Through specific grinding, papermaking, drying and calendaring processes, a protection paper with certain air permeability and operability is obtained. However, this method relies on natural fibers and does not undergo in-depth chemical modification and functionalization design, resulting in a relatively large thickness of the protection paper (basis weight 48-52 g / m 2 ), general optical performance (transmittance about 85%), unstable antistatic performance (surface resistance 50-2000 MΩ), and easy shedding of lint and powder, which is difficult to meet the strict requirements of high-end screens for ultra-thin, high-transmittance, high-cleanliness and long-lasting antistatic properties.

[0003] With the development of electronic screens towards ultra-high definition and flexibility, the performance requirements of protection paper are increasingly high. The protection paper in the prior art often uses simple fiber mixing and surface coating of antistatic agents, which has the problems of fast antistatic performance decay, large sacrifice of optical performance, and difficulty in further reducing the thickness. In particular, although conventional quaternary ammonium salt antistatic agents are widely used, they are prone to migration and decomposition, resulting in unstable antistatic performance; while simple fiber compounding can improve mechanical properties, it is difficult to achieve ultra-thin thickness and excellent optical performance at the same time. Therefore, it is an urgent need in the industry to develop a new type of protection paper that integrates ultra-thin, high-strength, high-transmittance and long-lasting antistatic properties.

[0004] Based on the above technical bottlenecks, the present application innovatively proposes to construct functional composite fibers with core-shell structure, introduce surface-modified nano-silica aerogel particles, and combine the latest plasma pretreatment and magnetron sputtering surface treatment technology to prepare high-performance protection paper. This method realizes the multifunctional integration of protection paper through molecular-level design and the application of nanotechnology, solves the core problems in the prior art, and has significant creativity and practicality. SUMMARY

[0005] The application aims to provide a preparation method of high-definition electronic screen protection paper to solve the technical problems of the existing protection paper, such as the large thickness affecting the packaging space efficiency, the insufficient surface cleanliness easily causing screen pollution, the poor optical performance affecting the color development authenticity of quality inspection, and the unstable antistatic performance. The special protection paper with the characteristics of ultra-thin thickness, high mechanical strength, high light transmittance, low haze and persistent and stable antistatic performance is prepared by constructing the functional composite fiber with core-shell structure to realize persistent antistatic, introducing the surface modified nano-silica aerogel particles to optimize the optical performance, and combining the advanced processes such as plasma pretreatment and magnetron sputtering surface treatment, so as to meet the harsh requirements of high-end liquid crystal display screen and OLED screen on the protection material in the production and transportation process.

[0006] A preparation method of high-definition electronic screen protection paper comprises the following steps: S1, constructing the functional composite fiber with core-shell structure: taking the regenerated cellulose fiber as the core layer, constructing the polypyrrole / graphene composite conductive layer as the shell layer on the surface thereof through in-situ polymerization; S2, preparing the surface modified nano-silica aerogel particles: preparing the nano-silica aerogel through the sol-gel method, and then performing surface modification on the nano-silica aerogel by using the fluorine-containing silane; S3, preparing the polyimide fiber modified by the silane coupling agent: soaking the polyimide fiber in the ethanol solution of 3-aminopropyl triethoxysilane for surface modification; S4, fiber compounding: mixing the functional composite fiber with core-shell structure obtained in step S1, the surface modified nano-silica aerogel particles obtained in step S2, and the polyimide fiber modified by the silane coupling agent obtained in step S3, adding the bio-based wet strength agent and the fluorocarbon defoaming agent, and performing plasma pretreatment and grinding treatment to obtain the mixed slurry; S5, performing the wire-pressing papermaking treatment on the mixed slurry in step S4 to obtain the formed wet paper sheet; S6, sequentially performing vacuum suction, pressing dewatering, and controllable drying on the formed wet paper sheet in step S5 until the water content of the paper sheet is 3.0-5.0% to obtain the base paper; S7, performing the surface treatment on the base paper in step S6 by magnetron sputtering to deposit a layer of indium tin oxide transparent conductive layer with the thickness of 50-100 nm; S8, performing the paper defect monitoring and winding on the paper sheet treated in step S7 to obtain the high-definition electronic screen protection paper.

[0007] Preferably, the preparation of the functional composite fiber with core-shell structure in step S1 comprises: dispersing regenerated cellulose fibers in deionized water to form a dispersion with a solid-liquid ratio of 1 g: (10-15) mL, adding pyrrole monomers and graphene oxide, adding 3-6% ammonium persulfate aqueous solution as oxidant at a rate of 1-2 drops per second in an ice water bath at 0-5℃, and reacting for 4-6 hours, wherein the mass ratio of pyrrole monomers to regenerated cellulose fibers is 1: (5-10), the addition amount of graphene oxide is 10-20% of the mass of pyrrole monomers, and the molar ratio of ammonium persulfate to pyrrole monomers is (0.8-1.2): 1.

[0008] Preferably, the preparation of the surface-modified nanosilica aerogel particles in step S2 comprises: mixing tetraethyl orthosilicate as a precursor with anhydrous ethanol and deionized water at a mass ratio of 1: (8-12): (1.5-2.5), adjusting the pH to 2.5-3.5 with acid, hydrolyzing at 50-70℃ for 1.5-2.5 hours, then adjusting the pH to 7.5-8.5 with base for condensation for 3-5 hours to form a gel, drying with supercritical carbon dioxide to obtain nanosilica aerogel, and then dispersing the nanosilica aerogel and perfluorodecyltriethoxysilane in anhydrous ethanol at a mass ratio of 1: (0.7-0.9) and refluxing at 80-100℃ for 2-4 hours to complete the surface modification.

[0009] Preferably, the preparation of the silane coupling agent modified polyimide fiber in step S3 comprises: soaking polyimide chopped fibers with a length of 2-4 mm and a diameter of 10-15 μm in a 1-3 wt% 3-aminopropyltriethoxysilane ethanol solution, with a solid-liquid ratio of 1 g: (6-10) mL, and constant temperature oscillation reaction at 60-80℃ for 1-2 hours. After the reaction is completed, wash with ethanol for 2-4 times.

[0010] Preferably, the mixed slurry in step S4 is composed of the following components in mass percentage: functional composite fiber with core-shell structure 60-80%, surface-modified nanosilica aerogel particles 5-15%, silane coupling agent modified polyimide fiber 10-20%, bio-based wet strength agent 1-3%, and fluorocarbon defoamer 0.5-1%; the bio-based wet strength agent is a chitosan derivative with a deacetylation degree of ≥85%; the chitosan derivative is any one of carboxymethyl chitosan, hydroxypropyl chitosan or quaternized chitosan; and the molecular weight of the chitosan derivative is 50000-200000 Da.

[0011] Preferably, the plasma pretreatment conditions in step S4 are: low temperature plasma treatment, power of 500-800 W, treatment time of 2-5 minutes, working gas pressure of 40-60 Pa, and mixed gas of argon and oxygen with a volume ratio of argon to oxygen of (3-5): 1.

[0012] Preferably, the step S4 adopts a nano-beating technology, the beating gap is 10-20 μm, the beating degree is 35-45 °SR, the wet weight is 4.0-6.0 g, and the pulp concentration is controlled at 3.5-4.5%.

[0013] Preferably, the step S6 adopts a three-stage drying process, the first stage temperature is 80-100 ℃, the drying time is 1-2 minutes; the second stage temperature is 120-140 ℃, the drying time is 2-3 minutes; the third stage temperature is 160-180 ℃, the drying time is 1-2 minutes, and the temperature deviation of each stage is controlled within ±2 ℃.

[0014] Preferably, the step S7 adopts the following process parameters of the magnetron sputtering surface treatment: an indium tin oxide composite target is used, the mass ratio of In2O3, SnO2 and ZnO is (8-10):1:(1-0.5), the substrate temperature is 100-150 ℃, the sputtering power is 200-300 W, the working pressure is 0.5-1.0 Pa, the argon flow rate is 20-30 sccm, and the deposition time is 20-40 minutes; the preparation method of the indium tin oxide composite target is as follows: In2O3, SnO2 and ZnO powders are mixed in proportion, ball milling is performed for 4-6 hours, the ball-to-material ratio is (3-5):1, and the rotation speed is 300-500 rpm; sintering is performed at 1000-1200 ℃ to form the composite target; and the composite target is used in the magnetron sputtering.

[0015] The core innovation of the application is to construct a functional composite fiber with a core-shell structure. The regenerated cellulose fiber is used as a core layer, and a polypyrrole / graphene composite conductive layer is constructed on the fiber surface as a shell layer through in-situ polymerization. Polypyrrole, as a conductive polymer, can form a continuous conductive network on the fiber surface through oxidation-reduction reaction; the addition of graphene further enhances the conductivity and mechanical strength. This core-shell structure not only realizes durable antistatic performance, but also maintains the flexibility and optical transparency of the fiber, solving the problems of easy migration and unstable performance of traditional antistatic agents.

[0016] Another innovation is the introduction of surface-modified nano-silica aerogel particles. The nano-silica aerogel prepared by the sol-gel method has extremely high specific surface area and porosity. After surface modification with fluorine-containing silane, the surface energy is significantly reduced, and the compatibility with the fiber is improved. These nanoparticles form a uniformly dispersed nano-scale pore structure in the paper, which not only ensures extremely high light transmittance and low haze, but also enhances the mechanical strength and dimensional stability of the paper through the nano effect.

[0017] In addition, the present application adopts a plurality of the latest material processing and surface technologies. The fiber surface is activated by plasma pretreatment, improving the bonding force of the subsequent composite material; the polyimide fiber is modified by silane coupling agent, enhancing the interface bonding between the fiber and the matrix; the transparent conductive layer of indium tin oxide is deposited on the paper surface by magnetron sputtering, further improving the antistatic performance and surface smoothness; the synergistic application of these technologies realizes the qualitative leap of the performance of the protective paper.

[0018] The beneficial technical effects of the present application are: 1. The high-definition electronic screen protective paper prepared by the present application has excellent optical performance. The light transmittance is as high as 95% or more, and the haze is less than 2%, which is much better than traditional protective paper, ensuring true color and uniform brightness during screen quality inspection. This is mainly due to the nanoscale pore structure of the nanosilica aerogel and the surface modification technology, which effectively reduces light scattering, while the functional composite fiber with core-shell structure maintains good light transmittance.

[0019] 2. In terms of antistatic performance, the protective paper shows a stable low surface resistance (10-50 MΩ). The conductive layer of polypyrrole / graphene in the core-shell structure forms a three-dimensional conductive network, which can maintain stable charge dissipation ability even in high humidity environment, effectively preventing static adsorption of dust. The indium tin oxide layer deposited by magnetron sputtering further enhances the surface conductivity without affecting the optical performance.

[0020] 3. The mechanical performance and cleanliness of the protective paper are also excellent. The thickness is only 0.08-0.12 mm, the basis weight is 45-51 g / m 2 , the longitudinal tensile strength is ≥4.5 kN / m, the transverse tensile strength is ≥2.5 kN / m, the stiffness is moderate, and it is easy to operate. The lint and powder shedding rate is less than 0.05%, the surface is smooth and defect-free, ensuring that it will not contaminate the surface of the precision screen. The synergistic improvement of these performances makes the protective paper of the present application an ideal choice for high-end electronic screen protection. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The process flow chart of the preparation method of the high-definition electronic screen protective paper of the present application is shown in the figure; Figure 2 The construction schematic of the core-shell structure functional composite fiber of the present application is shown in the figure; Figure 3 The structure schematic of the surface modified nanosilica aerogel particles of the present application is shown in the figure; The names of the components marked in the figure are as follows: 201 represents the graphene composite layer, 202 represents the polypyrrole conductive layer, and 203 represents the regenerated cellulose fiber core layer; 301 represents the surface modification layer, 302 represents the fluorine group, and 303 represents the nanosilica aerogel core. DETAILED DESCRIPTION

[0022] Before further description of the present application, it is to be understood that the application is not limited to the particular specific embodiments described herein; it is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Any methods, devices and materials similar or equivalent to those described herein can be used in the practice of the present application, unless specifically stated otherwise.

[0023] When numerical ranges are given, it should be understood that every numerical value between the two endpoints, and any numerical value in between, is also contemplated unless otherwise indicated. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Any methods, devices and materials similar or equivalent to those described herein can be used in the practice of the present application, unless specifically stated otherwise.

[0024] Unless otherwise indicated, the test methods, test procedures, and preparation methods disclosed herein are conducted according to conventional techniques in the art.

[0025] Example 1 First, the core-shell structure functional composite fiber was constructed. 85 parts of regenerated cellulose fiber was dispersed in 1020 parts of deionized water (solid-liquid ratio of 1:12 g / mL) to form a uniform dispersion under stirring at a speed of 500 rpm; then 9.4 parts of pyrrole monomer and 1.7 parts of graphene oxide were added to the system, and the temperature was kept at 4°C in an ice water bath. A 5% ammonium persulfate aqueous solution was slowly added as an oxidizing agent at a rate of 1-2 drops per second (the molar ratio of ammonium persulfate to pyrrole monomer was 1:1), and the reaction was allowed to proceed for 5.5 hours to form a dense polypyrrole / graphene composite conductive shell layer on the fiber surface by in-situ polymerization of pyrrole. The thickness of the graphene composite layer was 100 nm. Meanwhile, surface-modified nano-silica aerogel was prepared. 22 parts of tetraethyl orthosilicate were used as a precursor, 220 parts of absolute ethanol and 44 parts of deionized water were added, and the pH was adjusted to 2.5 with hydrochloric acid. The mixture was stirred in a 60°C water bath for 2.5 hours for hydrolysis, then the pH was adjusted to 7.5 with ammonia water, and the stirring was continued for 4.5 hours for condensation to form a gel. After supercritical carbon dioxide drying (critical temperature 31°C, critical pressure 7.4 MPa), 8.8 parts of nano-silica aerogel were obtained. The nano-silica aerogel and 7.0 parts of perfluorodecyltriethoxysilane (mass ratio 1:0.8) were dispersed in 88 parts of absolute ethanol, and the surface modification was completed by refluxing at 95°C for 3.5 hours. The specific surface area of the surface-modified nano-silica aerogel particles was 600 m 2g; then the polyimide fibers (short cut fibers with a length of 3 mm and a diameter of 12 pm are selected) are treated, 12 parts of polyimide fibers are soaked in 96 parts of a 3-aminopropyltriethoxysilane ethanol solution with a concentration of 2.5 wt% (solid-liquid ratio 1:8), and the silane coupling agent modification is completed by constant temperature oscillation reaction at 75 °C for 1 hour, and then the polyimide fibers are washed with ethanol three times; then slurry compounding is performed, 75% of functional composite fibers, 8% of surface modified nano-silica aerogel particles, 12% of modified polyimide fibers, 1.5% of a bio-based wet strength agent (the bio-based wet strength agent is carboxymethyl chitosan with a degree of deacetylation of 92% and a number average molecular weight of 150000 Da), and 0.9% of a fluorocarbon-based defoaming agent are taken by mass percentage, and after mixing, high-speed dispersion is performed at 1000 rpm for 30 minutes, and then low-temperature plasma treatment is performed to fully activate the surface of the fibers, under the conditions of a power of 700 W, an atmosphere of argon and oxygen with a volume ratio of 4:1, and a working gas pressure of 50 Pa for 3.5 minutes; then nano-scale beating is performed, the beating gap is controlled to be 18 pm, the beating degree reaches 42°SR, and the wet weight is 5.5 g; the papermaking is performed on a fourdrinier paper machine, the forming screen is 80 mesh, the machine speed is 280 m / min, and the net section dehydration pressure is 0.25 MPa; the wet paper sheet after dehydration is dried by a three-stage controllable drying process, the first stage is dried at 95 °C for 1 minute, the second stage is dried at 135 °C for 2 minutes, and the third stage is dried at 175 °C for 1 minute, so that the water content of the paper is reduced to 4.5%; finally, an indium tin oxide transparent conductive layer is deposited on the surface of the paper by magnetron sputtering, an ITO composite target (mass ratio: In2O3: SnO2: ZnO is 9: 1: 0.5; the preparation method of the indium tin oxide composite target is as follows: In2O3, SnO2 and ZnO powders are mixed in proportion, ball milling for 4 hours, wherein the ball-to-material ratio is 5:1 and the rotation speed is 300 rpm; sintering at 1100 °C to form a composite target; during magnetron sputtering, the composite target is used), the substrate temperature is 140 °C, the sputtering power is 280 W, the working gas pressure is 0.9 Pa, the argon flow rate is 28 sccm, the deposition time is 35 minutes, the deposition thickness is 90 nm, and the final protective paper product is obtained after paper disease monitoring and winding. The high-definition electronic screen protective paper prepared in Example 1 has a thickness of 0.11 mm.

[0026] Example 2 First, the core-shell structure functional composite fiber is constructed, 75 parts of regenerated cellulose fiber is dispersed in 900 parts of deionized water (solid-liquid ratio is 1:12), and is stirred to form a uniform dispersion under the speed of 500 rpm; then 12.5 parts of pyrrole monomer and 1.5 parts of graphene oxide are added to the system, and the system is kept at 2°C in an ice water bath. A 5% ammonium persulfate aqueous solution is slowly added as an oxidizing agent at a rate of 1-2 drops per second (the molar ratio of ammonium persulfate to pyrrole monomer is 1:1), and the reaction is carried out for 4.5 hours to form a polypyrrole / graphene composite conductive shell layer on the fiber surface by in-situ polymerization of pyrrole. The thickness of the graphene composite layer is 100 nm; at the same time, the preparation of surface-modified nano-silica aerogel is carried out independently, 18 parts of tetraethyl orthosilicate are used as the precursor, 180 parts of anhydrous ethanol and 36 parts of deionized water are added, and the pH is adjusted to 3.5 with hydrochloric acid. The mixture is stirred in a 60°C water bath for 1.5 hours, then the pH is adjusted to 8.5 with ammonia water, and the stirring and condensation are continued for 3.5 hours to form a gel. After supercritical carbon dioxide drying (critical temperature 31°C, critical pressure 7.4 MPa), 7.2 parts of nano-silica aerogel are obtained. The obtained aerogel and 6.0 parts of perfluorodecyltriethoxysilane (mass ratio 1:0.83) are dispersed in 72 parts of anhydrous ethanol, and the surface modification is carried out by refluxing at 85°C for 2.5 hours. The specific surface area of the surface-modified nano-silica aerogel particles is 600 m 2(g); then the polyimide fibers (29 short fibers with a length of 3 mm and a diameter of 12 pm were selected) were treated by immersing 18 parts of the polyimide fibers in 144 parts of a 3-aminopropyltriethoxysilane ethanol solution with a concentration of 1.5 wt% (solid-liquid ratio 1:8) for silane coupling agent modification at 65°C for 2 hours of constant temperature oscillation reaction, and then washed with ethanol three times; then slurry compounding was performed, 65% functional composite fibers, 12% surface modified nano-silica aerogel particles, 18% modified polyimide fibers, 2.5% bio-based wet strength agent (the bio-based wet strength agent was carboxymethyl chitosan with a degree of deacetylation of 92% and a number average molecular weight of 150000 Da), and 0.7% fluorocarbon antifoam agent were taken by mass percentage, and after mixing, high-speed dispersion was performed at 1000 rpm for 30 minutes, and then low-temperature plasma treatment was performed to activate the fiber surface, under the conditions of a power of 550 W, an atmosphere of argon and oxygen with a volume ratio of 4:1, and a working gas pressure of 50 Pa for 2.5 minutes; then nano-scale beating was performed, the beating gap was controlled to be 12 pm, the beating degree reached 38°SR, and the wet weight was 4.5 g; the wire was formed on a Fourdrinier paper machine with a forming wire of 80 meshes, a machine speed of 220 m / min, and a wire section dewatering pressure of 0.15 MPa; the wet paper web after dewatering was dried by a three-stage controllable drying process, the first stage was dried at 85°C for 2 minutes, the second stage was dried at 125°C for 3 minutes, and the third stage was dried at 165°C for 2 minutes, so that the water content of the paper was reduced to 3.5%; finally, an indium tin oxide transparent conductive layer was deposited on the surface of the paper by magnetron sputtering, an ITO target material (mass ratio: In2O3: SnO2: ZnO was 9:1:0.5; the preparation method of the indium tin oxide composite target material was as follows: In2O3, SnO2 and ZnO powders were mixed in proportion, ball milled for 4 hours, wherein the ball-to-material ratio was 5:1 and the rotation speed was 300 rpm; the composite target material was prepared by sintering at 1100°C; during magnetron sputtering, the composite target material was used), the substrate temperature was 110°C, the sputtering power was 230 W, the working gas pressure was 0.6 Pa, the argon flow rate was 22 sccm, the deposition time was 25 minutes, the deposition thickness was 70 nm, and the final protective paper product was obtained after paper disease monitoring and winding. The high-definition electronic screen protective paper prepared in Example 2 had a thickness of 0.09 mm.

[0027] Example 3 First, the core-shell structure functional composite fiber is constructed, 80 parts of regenerated cellulose fiber is dispersed in 960 parts of deionized water (solid-liquid ratio is 1:12), and is stirred to form a uniform dispersion under the speed of 500 rpm; then 10 parts of pyrrole monomer and 1.5 parts of graphene oxide are added to the system, and the system is kept at 3°C in an ice water bath. A 5% ammonium persulfate aqueous solution is slowly added as an oxidizing agent at a rate of 1-2 drops per second (the molar ratio of ammonium persulfate to pyrrole monomer is 1:1), and the reaction is carried out for 5 hours to form a uniform polypyrrole / graphene composite conductive shell layer on the fiber surface by in-situ polymerization of pyrrole. The thickness of the graphene composite layer is 100 nm; at the same time, the preparation of surface-modified nano-silica aerogel is carried out independently, 20 parts of tetraethyl orthosilicate are used as the precursor, 200 parts of anhydrous ethanol and 40 parts of deionized water are added, and the pH is adjusted to 3 with hydrochloric acid. The mixture is stirred in a 60°C water bath for 2 hours for hydrolysis, then the pH is adjusted to 8 with ammonia water, and the stirring and condensation are continued for 4 hours to form a gel. After supercritical carbon dioxide drying (critical temperature 31°C, critical pressure 7.4 MPa), 8 parts of nano-silica aerogel are obtained. The obtained aerogel and 6.4 parts of perfluorodecyltriethoxysilane (mass ratio 1:0.8) are dispersed in 80 parts of anhydrous ethanol, and the surface modification is carried out by refluxing at 90°C for 3 hours. The specific surface area of the surface-modified nano-silica aerogel particles is 600 m 2g; then the polyimide fibers (29 short fibers with a length of 3 mm and a diameter of 12 pm were selected) were treated, 15 parts of polyimide fibers were soaked in 120 parts of a 3-aminopropyltriethoxysilane ethanol solution with a concentration of 2 wt% (solid-liquid ratio 1:8), and the silane coupling agent modification was completed by constant temperature oscillation reaction at 70°C for 1.5 hours, and then the polyimide fibers were washed with ethanol three times; then slurry compounding was performed, 70% functional composite fibers, 10% surface modified nano-silica aerogel particles, 15% modified polyimide fibers, 2% bio-based wet strength agent (the bio-based wet strength agent was carboxymethyl chitosan with a degree of deacetylation of 92% and a number average molecular weight of 150000 Da), and 0.8% fluorocarbon antifoam agent were taken by mass percentage, and after mixing, high-speed dispersion was performed at 1000 rpm for 30 minutes, and then low-temperature plasma treatment was performed to activate the fiber surface, under the conditions of a power of 600 W, an atmosphere of argon and oxygen with a volume ratio of 4:1, and a working gas pressure of 50 Pa for 3 minutes; then nano-scale beating was performed, the beating gap was controlled to be 15 pm, the beating degree reached 40°SR, and the wet weight was 5.0 g; the papermaking on the wire was performed on a fourdrinier paper machine, the forming wire mesh was 80 mesh, the machine speed was 250 m / min, and the wire section dehydration pressure was 0.2 MPa; the wet paper sheet after dehydration was dried by a three-stage controllable drying process, the first stage was dried at 90°C for 1.5 minutes, the second stage was dried at 130°C for 2.5 minutes, and the third stage was dried at 170°C for 1.5 minutes, so that the water content of the paper was reduced to 4.0%; finally, an indium tin oxide transparent conductive layer was deposited on the surface of the paper by magnetron sputtering, an ITO target material (mass ratio: In2O3: SnO2: ZnO was 9:1:0.5; the preparation method of the indium tin oxide composite target material was as follows: In2O3, SnO2 and ZnO powders were mixed in proportion, ball milling for 4 hours, wherein the ball-to-material ratio was 5:1 and the rotation speed was 300 rpm; the composite target material was prepared by sintering at 1100°C; during magnetron sputtering, the composite target material was used), the substrate temperature was 120°C, the sputtering power was 250 W, the working gas pressure was 0.8 Pa, the argon flow rate was 25 sccm, the deposition time was 30 minutes, the deposition thickness was 80 nm, and the final protective paper product was obtained after paper disease monitoring and winding. The high-definition electronic screen protective paper prepared in Example 3 had a thickness of 0.10 mm.

[0028] Comparative Example 1 Comparative Example 1 was implemented according to the traditional liquid crystal substrate protection paper manufacturing method: 70 parts of bleached sulfite softwood pulp subjected to mercerization treatment and 30 parts of bleached sisal pulp were used as raw materials, and after being separately defibrated, they were milled by using multiple double-disc refiners connected in series, with a beating specific pressure of 6 kg / cm for the softwood pulp, a beating degree of 23°SR, and a wet weight of 8.5 g, and a beating specific pressure of 7 kg / cm for the sisal pulp, a beating degree of 23°SR, and a wet weight of 11.0 g. After the milling was completed, the materials were proportioned and uniformly mixed, and a wet paper sheet was formed by using a long net single cylinder paper machine at a speed of 320 m / min. After the wet paper sheet was subjected to vacuum suction and press dewatering, it was dried by using a Yankee dryer with a diameter of 3660 mm, with a dryer surface temperature of 140°C, and by using an ion fan to supply air, with a hot air temperature of 190°C and an air flow speed of 60 m / s, until the paper moisture content reached 5.0%. The original paper was obtained. The original paper was rewetted to a moisture content of 7.0%, and then was subjected to double-side calendering treatment by using a double-roller soft calender, with the soft roller being pre-coated with an antistatic material, a calendering temperature of 190°C, and a linear pressure of 90 KN / m. After the calendering treatment, the paper sheet was de-electrified, and after paper defect monitoring, it was wound up. The high-definition electronic screen protection paper prepared in Comparative Example 1 had a thickness of 0.15 mm.

[0029] Comparative Example 2 In Comparative Example 2, a conventional antistatic agent was used instead of the core-shell structure design: 85 parts of regenerated cellulose fiber was used as raw material, without constructing the core-shell structure, directly adding 3 parts of conventional quaternary ammonium salt antistatic agent (hexadecyl trimethyl ammonium bromide) and 12 parts of unmodified polyimide fiber, adding 2% bio-based wet strength agent and 0.8% fluorocarbon defoaming agent, and then performing ordinary defibration and milling treatment, with a beating degree of 35°SR and a wet weight of 6.0 g. Subsequently, the paper was formed, pressed and dewatered, and conventionally dried (single temperature of 150°C for 5 minutes), and the steps of plasma pretreatment and magnetron sputtering surface treatment were omitted, and the paper was directly monitored for defects and wound up. The high-definition electronic screen protection paper prepared in Comparative Example 2 had a thickness of 0.12 mm.

[0030] Comparative Example 3 In Comparative Example 3, the nano-silica aerogel component was omitted: the core-shell structure functional composite fiber and the modified polyimide fiber were constructed according to the same process as in Example 1, the slurry ratio was adjusted to 80% functional composite fiber, 15% modified polyimide fiber, 2% bio-based wet strength agent, and 0.8% fluorocarbon defoaming agent, and the surface modified nano-silica aerogel particles were completely omitted; subsequently, the same plasma pretreatment, nano-scale milling, paper formation, three-stage controllable drying, and magnetron sputtering surface treatment as in Example 1 were performed. The high-definition electronic screen protection paper prepared in Comparative Example 3 had a thickness of 0.10 mm.

[0031] Comparative Example 4 Comparative Example 4: omitting magnetron sputtering surface treatment: following the same process as Example 1, the core-shell structure functional composite fiber construction, nano-silica aerogel preparation, fiber compounding, plasma pretreatment, refining, web forming, and controllable drying were all carried out, but after obtaining the base paper, paper disease monitoring and winding were directly carried out, and the surface treatment step of magnetron sputtering deposition of indium tin oxide transparent conductive layer was completely omitted. The high-definition electronic screen protection paper prepared in Comparative Example 4 has a thickness of 0.10 mm.

[0032] Comparative Example 5 Comparative Example 5: omitting plasma pretreatment: following the same formula as Example 1, the slurry was prepared, but after mixing, nano-refining was directly carried out, and the plasma pretreatment step was omitted; then the same web forming, three-stage controllable drying, and magnetron sputtering surface treatment as Example 1 were carried out. The high-definition electronic screen protection paper prepared in Comparative Example 5 has a thickness of 0.10 mm.

[0033] Performance test Test standard Quantitative (g / m 2 ), longitudinal tensile strength (kN / m), transverse tensile strength (kN / m), surface resistance (MΩ) refer to Chinese invention patent CN112593453A; Transmittance (%) and haze (%) refer to Chinese invention patent CN110552242B; Dust and powder shedding rate (%) refer to Chinese invention patent CN114166687A; Table 1 is the test results of each example Table 2 is the test results of each comparative example By comparing the data in Table 1 and Table 2, it can be seen that the protective paper prepared in Examples 1-3 of the present application is significantly better than all comparative examples in terms of transmittance (94-96%), haze (1.2-1.8%), surface resistance (20-30 MΩ), longitudinal tensile strength (4.6-5.0 kN / m), and dust and powder shedding rate (0.02-0.04%) and other key performance indicators. This shows that the present application realizes breakthrough improvement in ultra-thin, high-transmittance, high-strength, durable anti-static, and high-cleanliness of the protective paper by means of synergistic innovation such as constructing core-shell structure composite fibers (forming a stable conductive network), introducing surface-modified nano-silica aerogel (optimizing optical performance and enhancing mechanical strength), and using plasma pretreatment and magnetron sputtering surface treatment (enhancing fiber bonding and surface conductivity), effectively overcoming the performance deficiencies of traditional protective paper due to material selection and process limitations.

[0034] The slight differences in the properties of transmittance, tensile strength, surface resistance, etc. of Examples 1-3 are mainly due to the differences in the ratio of core-shell composite fibers, nano-silica aerogel and modified polyimide fibers in each example, as well as the fine tuning of process parameters such as plasma treatment power, refining gap, drying temperature, and magnetron sputtering time. For example, the functional composite fiber content in Example 1 is higher (75%) and the magnetron sputtering deposition time is longer (35 minutes), making the conductive layer more complete and the surface resistance lower (20 MΩ); the aerogel content in Example 2 is higher (12%), although the transmittance is slightly lower (94%), but the mechanical properties are enhanced; the parameters in Example 3 are moderate, and the performance is balanced. These differences reflect the fine control of component ratio and process conditions on the performance of the final product.

[0035] Reason analysis of the difference between the test results of the examples and Comparative Example 1: Comparative Example 1 uses traditional natural fiber raw materials and conventional process, without introducing functional composite fibers, nano-aerogel and surface treatment technology, resulting in low transmittance (85%), high haze (8.0%), poor tensile strength and extremely high surface resistance (1500 MΩ). The fundamental reason is the lack of core-shell conductive structure, nano-reinforced phase and surface functionalization design in the present application, which cannot achieve optical calibration, charge dissipation and fiber interface strengthening, thus falling behind in optical, mechanical and antistatic properties.

[0036] Reason analysis of the difference between the test results of the examples and Comparative Example 2: Comparative Example 2 uses conventional quaternary ammonium salt antistatic agent, without constructing a core-shell conductive structure, resulting in a surface resistance of 1100 MΩ and unstable antistatic performance. The reason is that quaternary ammonium salt is easy to migrate and decompose, and cannot form a persistent conductive network; at the same time, plasma and magnetron sputtering treatment are omitted, the fiber bonding force is weak, the rate of shedding and powdering is high (0.3%), and the optical performance (transmittance 88%) is also decreased due to the lack of light guiding effect of nano-aerogel.

[0037] Reason analysis of the difference between the test results of the examples and Comparative Example 3: Comparative Example 3 omits nano-silica aerogel, resulting in a significant decrease in transmittance (87%) and tensile strength (3.7 kN / m in the longitudinal direction), and an increase in haze to 4.5%. The reason is that the nano-porous structure of aerogel plays a key role in light scattering suppression and mechanical enhancement in the present application, and the absence of it leads to disorder of the internal light path and weak bonding between fibers, affecting the optical uniformity and overall strength.

[0038] Reason analysis of the difference between the test results of the examples and Comparative Example 4: Comparative Example 4 omits the magnetron sputtering surface treatment, although the core-shell fiber and aerogel are retained, the surface resistance is increased to 200 MΩ, and the rate of lint and powder (0.14%) is higher than that of the examples. This is because the surface charge dissipation capacity and surface densification of the ITO transparent conductive layer are missing, resulting in a decrease in antistatic performance and surface smoothness, affecting the cleanliness and static protection effect during use.

[0039] Reason analysis of the difference between the test results of the examples and Comparative Example 5: Comparative Example 5 omits the plasma pretreatment, resulting in a decrease in the bonding force between the fibers, a decrease in the longitudinal tensile strength to 4.3 kN / m, and an increase in the rate of lint and powder to 0.11%. The reason is that the plasma treatment can activate the fiber surface and improve the interfacial compatibility, and the absence of the plasma treatment affects the overall strength and cleanliness of the paper, although the conductive and optical properties are less affected.

[0040] Finally, it should be noted that the above examples are used to illustrate the technical solutions of the present application and not to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method of making a high definition electronic screen protector paper, characterized by, The method comprises the following steps: S1, constructing a functional composite fiber with a core-shell structure: taking regenerated cellulose fiber as a core layer, and constructing a polypyrrole / graphene composite conductive layer as a shell layer on the surface thereof through in-situ polymerization; S2, preparing surface-modified nano-silica aerogel particles: preparing nano-silica aerogel through a sol-gel method, and then performing surface modification on the nano-silica aerogel by using a fluorine-containing silane; S3, preparing silane coupling agent-modified polyimide fibers: soaking polyimide fibers in an ethanol solution of 3-aminopropyl triethoxysilane to perform surface modification; S4, fiber compounding: mixing the functional composite fiber with a core-shell structure obtained in step S1, the surface-modified nano-silica aerogel particles obtained in step S2, and the silane coupling agent-modified polyimide fibers obtained in step S3, adding a bio-based wet strength agent and a fluorocarbon defoaming agent, and then performing plasma pretreatment and grinding treatment to obtain a mixed pulp; S5, performing on-loom papermaking treatment on the mixed pulp obtained in step S4 to obtain a formed wet paper sheet; S6, sequentially performing vacuum suction, press dewatering, and controllable drying on the formed wet paper sheet obtained in step S5 until the water content of the paper sheet is 3.0-5.0% to obtain a base paper; S7, performing surface treatment on the base paper obtained in step S6 by using a magnetron sputtering method to deposit a layer of indium tin oxide transparent conductive layer with a thickness of 50-100 nm; S8, performing paper defect monitoring and winding on the paper sheet treated in step S7 to obtain a high-definition electronic screen protection paper.

2. The method of claim 1, wherein, The preparation of the functional composite fiber with a core-shell structure in step S1 comprises the following steps: dispersing regenerated cellulose fibers in deionized water to form a dispersion liquid with a solid-liquid ratio of 1 g:(10-15) mL, adding pyrrole monomers and graphene oxide, and adding an ammonium persulfate aqueous solution with a concentration of 3-6% as an oxidizing agent at a rate of 1-2 drops per second in an ice water bath at 0-5 ℃, and reacting for 4-6 hours, wherein the mass ratio of the pyrrole monomers to the regenerated cellulose fibers is 1:(5-10), the addition amount of the graphene oxide is 10-20% of the mass of the pyrrole monomers, and the molar ratio of the ammonium persulfate to the pyrrole monomers is (0.8-1.2):1; in the functional composite fiber with a core-shell structure, the thickness of the graphene composite layer is 50-200 nm.

3. The method of claim 1, wherein, The preparation of the surface-modified nanosilica aerogel particles in step S2 comprises: mixing tetraethyl orthosilicate as a precursor with anhydrous ethanol and deionized water at a mass ratio of 1:(8-12):(1.5-2.5), adjusting pH to 2.5-3.5 with an acid, hydrolyzing at 50-70℃ for 1.5-2.5 hours, then adjusting pH to 7.5-8.5 with a base for condensation for 3-5 hours to form a gel, drying by supercritical carbon dioxide to obtain nanosilica aerogel, and then dispersing the nanosilica aerogel and perfluorodecyltriethoxysilane at a mass ratio of 1:(0.7-0.9) in anhydrous ethanol, and refluxing at 80-100℃ for 2-4 hours to complete the surface modification; the specific surface area of the surface-modified nanosilica aerogel particles is 500-800m 2 / g.

4. The method of claim 1, wherein, The preparation of the silane coupling agent-modified polyimide fibers in step S3 comprises the following steps: soaking polyimide short-cut fibers with a length of 2-4 mm and a diameter of 10-15 μm in an ethanol solution of 3-aminopropyl triethoxysilane with a concentration of 1-3 wt%, with a solid-liquid ratio of 1 g:(6-10) mL, and oscillating at a constant temperature of 60-80 ℃ for 1-2 hours; and after the reaction is completed, washing the fibers with ethanol for 2-4 times.

5. The method of claim 1, wherein, The mixed slurry in the step S4 is composed of the following components in mass percentage: functional composite fibers with core-shell structure 60-80%, surface-modified nano-silica aerogel particles 5-15%, silane coupling agent modified polyimide fibers 10-20%, bio-based wet strength agent 1-3%, fluorocarbon-based defoaming agent 0.5-1%; the bio-based wet strength agent is a chitosan derivative with deacetylation degree ≥85%; the chitosan derivative is any one of carboxymethyl chitosan, hydroxypropyl chitosan or quaternized chitosan; the molecular weight of the chitosan derivative is 50000-200000 Da.

6. The method of claim 1, wherein, The plasma pretreatment in the step S4 is performed at a power of 500-800 W, a treatment time of 2-5 minutes, and a working gas pressure of 40-60 Pa, using a low-temperature plasma treatment, and the gas is a mixture of argon and oxygen with a volume ratio of argon to oxygen being (3-5):

1.

7. The method of claim 1, wherein: The refining treatment in the step S4 is performed using a nanoscale refining technology, with a refining gap of 10-20 μm, a beating degree of 35-45°SR, a wet weight of 4.0-6.0 g, and a slurry concentration controlled at 3.5-4.5%.

8. The method of claim 1, wherein, The controllable drying in the step S6 is performed using a three-stage drying process: the first stage is at a temperature of 80-100℃ for 1-2 minutes; the second stage is at a temperature of 120-140℃ for 2-3 minutes; and the third stage is at a temperature of 160-180℃ for 1-2 minutes, with a temperature deviation of each stage being controlled within ±2℃.

9. The method of claim 1, wherein, The process parameters of the magnetron sputtering surface treatment in the step S7 are as follows: an indium tin oxide composite target is used, with a mass ratio of In2O3 to SnO2 to ZnO being (8-10):1:(1-0.5), a substrate temperature of 100-150℃, a sputtering power of 200-300 W, a working gas pressure of 0.5-1.0 Pa, an argon flow rate of 20-30 sccm, and a deposition time of 20-40 minutes; the preparation method of the indium tin oxide composite target is as follows: In2O3, SnO2 and ZnO powders are mixed in proportion, ball-milled for 4-6 hours, with a ball-to-material ratio of (3-5):1 and a rotation speed of 300-500 rpm; sintered at 1000-1200℃ to form a composite target; and the composite target is used in the magnetron sputtering.

10. A high definition electronic screen protector paper characterized by, Prepared by the method of any one of claims 1-9.

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