High dielectric flame retardant thin film and fast response electronic paper

Abstract

The application discloses a high-dielectric constant flame-retardant film, and a preparation method thereof, which comprises the following steps: dissolving polyvinyl alcohol in water to obtain a polyvinyl alcohol aqueous solution, adding phosphine / silicon amphiphilic compounds into the polyvinyl alcohol aqueous solution, and then adding boric acid, uniformly mixing, and then coating on a substrate, and drying to obtain the high-dielectric constant flame-retardant film. The application further discloses a fast-response electronic paper, and a preparation method thereof, which comprises the following steps: constructing a metal template with a micro-cup structure by using a laser etching processing method, placing the metal template on the high-dielectric constant flame-retardant film, and performing nano-imprinting by using a nano-imprinting device to manufacture the micro-cup structure. The film is prepared by compounding OP-KH and PVA, and the flame-retardant property is enhanced. The addition of the OP-KH with amphiphilic property greatly improves the dielectric constant of the film and improves the hydrophobicity of the surface, the high hydrophobic interface reduces the adhesion of electrophoretic particles and the micro-cup interface, reduces the desorption time of the particles on the surface, and greatly improves the response time when the film is applied to the micro-cup type electronic paper base film.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electronic paper, in particular to a high dielectric flame-retardant film and fast response electronic paper. BACKGROUND

[0002] Electronic paper is a general term for reflective-type paper-like displays that combine the reading comfort of traditional paper with the multifunctionality of modern electronic devices. The response speed and refresh rate of electronic paper are important indicators for evaluating the display quality of electronic paper. Fast response and high refresh rate mean that electronic paper can quickly update the display content, reduce the delay during image changes, and provide users with a smoother visual experience.

[0003] Electrophoretic electronic paper is a rapidly developing variety of electronic paper, and according to the different microcavities that carry electrophoretic particles, it is divided into microcapsule type and microcup type electrophoretic display. Microcup type electronic paper is to press out microcups from high molecular materials, then fill ink in the microcups, and then package the cup mouth, and the upper and lower surfaces of the microcups are connected to electrodes. The movement of electrophoretic particles between electrodes is realized by driving the microcups. The voltage applied between the two electrodes is partly allocated to the packaging layer and the other part is allocated to the electrophoretic fluid. Since the polymer is not conductive, the voltage share allocated to the two ends of the electrophoretic fluid is low, which leads to a decrease in particle movement rate and an increase in device response time. Experiments show that increasing the dielectric constant of the polymer layer is one of the methods to improve the response speed of the particles.

[0004] The refresh rate of electronic paper depends on the movement speed of electronic ink particles and the desorption speed of ink particles from the electrode surface. If the ink particles are firmly bonded to the surface and are not easily separated from the electrode surface, the refresh will be delayed. And the polymer as the microcup substrate is a flammable material, and the encapsulated electronic ink mainly contains isomeric alkanes, which are also flammable. SUMMARY

[0005] The purpose of the present application is to overcome the defects of the prior art, and to provide a high dielectric flame-retardant film. The preparation method is as follows: polyvinyl alcohol is dissolved in water to obtain a polyvinyl alcohol aqueous solution, phosphine / silicon amphiphilic compound is added to the polyvinyl alcohol aqueous solution, boric acid is added, and the mixture is uniformly coated on the substrate, and then dried to obtain a high dielectric flame-retardant film.

[0006] Further, the preparation method of the phosphine / silicon amphiphilic compound is as follows: 2-methyl-1,2-oxaphosphorin-5-ketone 2-oxide and KH550 are mixed according to a molar ratio of 1:1, and the reaction equation is as follows:

[0007] Compound)

[0008] Further, the reaction conditions are 100℃ for 2 hours.

[0009] Further, the amount of polyvinyl alcohol is 90wt% to 70wt% of the total mass of polyvinyl alcohol and phosphine / silicon amphiphilic compound, the amount of phosphine / silicon amphiphilic compound is 10wt% to 30wt% of the total mass of polyvinyl alcohol and phosphine / silicon amphiphilic compound, and the amount of boric acid is 3wt% of the mass of polyvinyl alcohol.

[0010] Further, the amount of polyvinyl alcohol is 90wt% to 70wt% of the total mass of polyvinyl alcohol and phosphine / silicon amphiphilic compound, the amount of phosphine / silicon amphiphilic compound is 10wt% to 30wt% of the total mass of polyvinyl alcohol and phosphine / silicon amphiphilic compound, and the amount of boric acid is 3wt% of the mass of polyvinyl alcohol.

[0011] Further, the thickness of the high dielectric flame-retardant film is 40 to 50um.

[0012] A high dielectric flame-retardant film prepared rapid response electronic paper, the preparation method is as follows: a metal mold with micro-cup structure is constructed by using laser etching processing method, the metal mold is placed on the high dielectric flame-retardant film, and nano-imprinting equipment is used for imprinting to manufacture the micro-cup structure.

[0013] Further, the micro-cup is a regular hexagon, the length of the regular hexagon is 10 to 100um, the gap between the two regular hexagons is 1 to 50um, and the height of the micro-cup is 10 to 50um. Further, the gap between the two regular hexagons is 3um, and the height of the regular hexagon of the mold is 30um.

[0014] Further, the imprinting step is as follows: under the pressure of 200psi, the temperature is 80 to 95℃, the imprinting is performed for 20 to 30min, then the temperature is reduced to 30℃ at the speed of 2℃ / min, and the temperature is maintained for 10min, the pressure is removed, and the high dielectric flame-retardant film with micro-cup structure is obtained.

[0015] 1. The film is prepared by compounding OP-KH and PVA, the flame-retardant performance is enhanced, the flame-retardant performance of the composition is excellent, and the vertical combustion grade of the tested composition reaches UL-94V-0 level.

[0016] 2. The addition of OP-KH with amphiphilicity greatly improves the dielectric constant of the film and the surface hydrophobicity, the high hydrophobic interface can reduce the adhesion of inorganic electrophoretic particles and the micro-cup interface, reduces the desorption time of particles on the surface, and greatly improves the response time when the film is applied to the micro-cup type electronic paper base film. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is an electronic paper micro-cup morphology of the application;

[0018] Figure 2 It is the response time test result of the electronic paper of the application. Detailed Implementation

[0019] The present invention is further illustrated below by means of examples and comparative examples. Unless otherwise specified, all pharmaceutical products used in the following examples are commercially available products, and all methods used are conventional methods in the art.

[0020] Example 1

[0021] 2-Methyl-1,2-oxosin-5-one 2-oxide and KH550 were mixed in a molar ratio of 1:1 and reacted at 100°C for 2 hours to obtain a phosphine / silicon amphiphilic compound (OP-KH).

[0022] Polyvinyl alcohol (PVA) was dissolved in distilled water at 90°C until completely dissolved, preparing a 10% (w / w) aqueous solution of PVA. At room temperature, OP-KH (30 wt% of the total mass of PVA and the phosphine / silicon amphiphilic compound) and boric acid (3 wt% of the mass of PVA) were added to the PVA aqueous solution. Mechanical stirring was used until the boric acid, OP-KH, and PVA formed a homogeneous solution. The homogeneous solution was degassed and allowed to stand for 10 minutes. A film was coated onto a smooth, clean, dry glass plate using a coating applicator. The film was dried in an oven at 100°C for 12 hours to obtain a PVA / OPKH film (i.e., the high dielectric flame-retardant film of this invention), with a film thickness of 50 micrometers.

[0023] Example 2

[0024] The metal mold is precisely placed on the film, and the microcup structure is created by imprinting using a nanoimprinting device. The imprinting process is as follows: imprint at a pressure of 200 psi and a temperature of 80-95℃ for 20-30 minutes, then reduce the temperature to 30℃ at a rate of 2℃ / min, hold for 10 minutes, remove the pressure, and obtain a film with a microcup structure.

[0025] Preparation of PVA blank membrane: PVA was dissolved in distilled water at 90℃ and stirred until completely dissolved to prepare a 10% PVA aqueous solution. The aqueous solution was degassed and allowed to stand for 0.5 h. A coating film was applied to a smooth, clean, dry glass plate using a coating applicator. The film was dried in a 70℃ oven for 12 h to obtain the PVA blank membrane. A microcup structure was then prepared according to the microcup structure preparation method described above and named the sample PVA.

[0026] Microcup-structured thin film samples PVA-1, PVA-2, and PVA-3 were prepared with the amount of phosphine / silicon amphiphilic compound being 10 wt% to 30 wt% of the total mass of polyvinyl alcohol and phosphine / silicon amphiphilic compound.

[0027] The prepared PVA / OP-KH films were evaluated by GB / T 2406-2008 "Plastics - Determination of the flammability of plastic materials - Part 1: Test methods - Glow-wire method" and GB / T 2408-2008 "Plastics - Determination of the flammability of plastic materials - Part 1: Test methods - Glow-wire method", and the results showed that the limiting oxygen index of PVA and PVA-1 was 18.5, 22.5, respectively, and the horizontal burning did not achieve any grade, while the burning grade of PVA-2 and PVA-3 reached UL-94 V-0 level, which indicated that the phosphine / silicon amphiphilic compound had flame retardant properties, and the addition of the phosphine / silicon amphiphilic compound improved the flame retardant properties of the PVA / OP-KH film, as shown in Table 1.

[0028] Table 1 Flame retardant properties and contact angle of PVA / OP-KH film

[0029]

[0030] The dielectric properties of the PVA / OP-KH film were tested, and the results are shown in Table 2, which indicated that the addition of OP-KH greatly improved the dielectric constant of the film.

[0031] Table 2 Dielectric constant of PVA / OP-KH film at different frequencies

[0032]

[0033] Figure 1 In the present application, the results of the topography profiler showed that the micro-cup structure of PVA-3 was regular, the micro-cup was a regular hexagon, the length of the side of the regular hexagon was 10-100 μm, the gap between two regular hexagons was 3 μm, and the height of the regular hexagon of the template was 30 μm. The response time of the PVA / OP-KH film was tested, and the results are shown in Figure 2 The response time of the micro-cup prepared by pure PVA was 195 ms, while the response time of the micro-cup with OP-KH was shortened, and the response time was shortest (44 ms) when the content of OP-KH was 30 wt% (PVA-3). The shorter the response time, the shorter the refresh time of the electronic paper display, and the less likely to have residual image, and the better the display effect for the user. The addition of the OP-KH with amphiphilic properties greatly improved the dielectric constant of the PVA film and the hydrophobicity of the surface. The high hydrophobic interface could reduce the adhesion of the inorganic electrophoretic particles and the micro-cup interface, reduce the desorption time of the particles on the surface, and greatly improve the response time when applied to the micro-cup type electronic paper base film.

[0034] The above-described embodiments are only used to illustrate the technical solutions of the present application, but not limit them; although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement to part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should be included in the protection scope of the present application.

Claims

1. A high dielectric, flame retardant film, characterized by, The preparation method is as follows: The polyvinyl alcohol is dissolved in water to obtain a polyvinyl alcohol aqueous solution, the phosphine / silicon amphiphilic compound is added to the polyvinyl alcohol aqueous solution, and then boric acid is added, and the mixture is uniformly coated on a substrate, and dried to obtain a high dielectric flame-retardant film; The preparation method of the phosphine / silicon amphiphilic compound is as follows: 2-methyl-1,2-oxaphosphorin-5-ketone 2-oxide and KH550 are mixed in a molar ratio of 1:1, and the reaction equation is as follows: ； The amount of polyvinyl alcohol is 90wt% to 70wt% of the total mass of polyvinyl alcohol and phosphine / silicon amphiphilic compound, the amount of phosphine / silicon amphiphilic compound is 10wt% to 30wt% of the total mass of polyvinyl alcohol and phosphine / silicon amphiphilic compound, and the amount of boric acid is 3wt% of the mass of polyvinyl alcohol.

2. The high dielectric flame-retardant film according to claim 1, characterized in that: In the preparation method of the phosphine / silicon amphiphilic compound, the reaction conditions are 100℃ for 2 hours.

3. The high dielectric flame-retardant film according to claim 1, characterized in that: The amount of polyvinyl alcohol is 90wt% of the total mass of polyvinyl alcohol and phosphine / silicon amphiphilic compound, the amount of phosphine / silicon amphiphilic compound is 30wt% of the total mass of polyvinyl alcohol and phosphine / silicon amphiphilic compound, and the amount of boric acid is 3wt% of the mass of polyvinyl alcohol.

4. The high dielectric flame-retardant film according to claim 1, characterized in that: The thickness of the high dielectric flame-retardant film is 40-50um.

5. The high dielectric, flame retardant thin film prepared fast response electronic paper of claim 1, characterized in that The preparation method is as follows: A metal template with a micro-cup structure is constructed by a laser etching method, the metal template is placed on the high dielectric flame-retardant film, and nano-imprinting equipment is used for imprinting to produce a micro-cup structure.

6. The fast-response electronic paper prepared from the high dielectric flame-retardant film according to claim 5, characterized in that: The micro-cups are regular hexagons, the side length of the regular hexagons is 10-100um, the gap between two regular hexagons is 1-50um, and the height of the micro-cups is 10-50um.

7. The fast-response electronic paper prepared from the high dielectric flame-retardant film according to claim 6, characterized in that: The gap between two regular hexagons is 3um, and the height of the regular hexagons of the template is 30um.

8. The high dielectric, flame retardant thin film prepared fast response electronic paper of claim 5, wherein, The imprinting step is as follows: Under a pressure of 200psi, the temperature is 80-95℃, the imprinting time is 20-30min, then the temperature is reduced to 30℃ at a speed of 2℃ / min, and the temperature is maintained for 10min, the pressure is removed, and a high dielectric flame-retardant film with a micro-cup structure is obtained.

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