Self-repairing display screen protective coating based on nano material and preparation method thereof

Abstract

The invention belongs to the technical field of display screen protective coatings, and particularly relates to a self-repairing display screen protective coating based on a nano material and a preparation method of the self-repairing display screen protective coating. The preparation method of the self-repairing display screen protective coating based on the nano material comprises the following steps: S1, adding quaternary ammonium salt POSS into isopropanol, uniformly mixing, then adding a sodium alginate aqueous solution, and fully stirring to obtain gel; s2, pouring the gel on the surface of a display screen substrate, and drying to obtain a POSS / sodium alginate coating; and S3, performing in-situ growth of nano titanium dioxide on the POSS / sodium alginate coating to obtain the self-repairing display screen protective coating based on the nano material.

Description

Technical Field

[0001] The present invention belongs to the technical field of display screen protective coatings, and in particular relates to a self-repairing display screen protective coating based on nanomaterials and a preparation method thereof. Background Art

[0002] Display screens are indispensable output devices in modern electronic devices, widely used in smartphones, computers, televisions, automobiles, industrial control, and other fields. Functional coatings can impart desirable properties to substrates such as displays, such as antireflection, UV shielding, antibacterial, self-cleaning, anti-fog, anti-fouling, anti-frost, anti-corrosion, and self-healing. Polymers are good candidates for the preparation of functional coatings due to their non-toxicity, good water solubility, and strong adhesion to numerous solid substrates. Furthermore, polymer coatings formed through covalent and non-covalent interactions can repair mechanical damage and restore original functionality in response to external stimuli such as water, light, and heat. Polymer coatings have attracted widespread attention due to their simple structure and relatively easy preparation methods.

[0003] A Chinese patent (publication number CN120059530A) discloses a self-repairing coating for a touch screen and a preparation method thereof. The self-repairing coating of the invention is formed by solidifying a sol formed by konjac glucomannan and POSS-modified nano-silica, wherein the content of the POSS-modified nano-silica decreases from the surface of the self-repairing coating to the inside, and the self-repairing coating is a multilayer stacked structure formed by sequentially applying sols containing different concentrations of the POSS-modified nano-silica to the surface of the touch screen and solidifying; the content of POSS-modified nano-silica on the surface of the self-repairing coating is relatively high, which can provide more active sites such as amino groups and hydroxyl groups, serving as "anchor points" for dynamic hydrogen bonds or dynamic chemical bonds, thereby increasing the strength of the damaged interface repair and improving the repair efficiency. However, the invention technology requires the formation of a multilayer stacked structure by POSS-modified nano-silica and graphene, which has a relatively complex preparation process, general self-repairing ability, and the coating hardness also needs to be improved.

[0004] Therefore, how to optimize the coating components, simplify the coating preparation method, obtain a self-repairing display screen protective coating based on nanomaterials, ensure good self-repairing ability while effectively improving the coating hardness has become a direction that needs to be focused on. Summary of the Invention

[0005] The present invention aims to provide a self-repairing display screen protective coating based on nanomaterials and a preparation method thereof. The present invention comprises the following steps: firstly, quaternary ammonium salt POSS and sodium alginate are mixed to form a gel; then, the gel is poured onto the surface of a display screen substrate to obtain a POSS / sodium alginate coating; then, titanium sulfate, deionized water, ammonia water and hydrogen peroxide are used as raw materials to prepare a peroxytitanic acid colloid; and then, in-situ growth of nano-titanium dioxide is achieved through composite treatment, thereby preparing a self-repairing display screen protective coating based on nanomaterials. The coating effectively improves the hardness of the coating while ensuring good self-repairing ability.

[0006] In order to achieve the above object, the present invention provides the following technical solutions: A first aspect of the present invention provides a method for preparing a self-repairing display screen protective coating based on nanomaterials, comprising the following steps: S1: Add quaternary ammonium salt POSS to isopropyl alcohol and mix well, then add sodium alginate aqueous solution and stir thoroughly to obtain a gel; S2: Casting the gel on the display substrate surface and obtaining a POSS / sodium alginate coating after drying; S3: In situ growth of nano-titanium dioxide on the POSS / sodium alginate coating to obtain a self-repairing display screen protective coating based on nanomaterials.

[0007] As a preferred solution, the weight parts of the components in step S1 include: 40-50 parts of quaternary ammonium salt POSS, 80-100 parts of isopropyl alcohol, and 90-100 parts of sodium alginate aqueous solution with a mass concentration of 8-10%.

[0008] As a preferred solution, the weight proportions of the quaternary ammonium salt POSS in the present invention can be 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts or 50 parts, etc.

[0009] As a preferred solution, the weight parts of the isopropyl alcohol in the present invention can be 80 parts, 85 parts, 90 parts, 95 parts or 100 parts, etc.

[0010] As a preferred solution, the weight proportions of the sodium alginate aqueous solution in the present invention can be 90 parts, 92 parts, 94 parts, 96 parts, 98 parts or 100 parts.

[0011] As a preferred solution, the mass concentration of the sodium alginate aqueous solution in the present invention can be 8%, 8.5%, 9%, 9.5% or 10%.

[0012] As a preferred solution, the preparation method of the quaternary ammonium salt POSS includes: using N,N-dimethylhexadecylamine and glacial acetic acid to quaternize the POSS material to obtain the quaternary ammonium salt POSS.

[0013] As a preferred solution, the POSS material is glycidyloxypropyl POSS.

[0014] As a preferred solution, the glycidyl ether oxypropyl POSS has a viscosity of 4800-500 cps and an epoxy equivalent of 165-170 g / eq.

[0015] As a preferred solution, the quaternization treatment step comprises: mixing 30 to 40 parts of glycidyloxypropyl POSS, 50 to 60 parts of toluene and 90 to 100 parts of isopropyl alcohol, stirring for 60 to 80 minutes, then adding 22 to 26 parts of N, N-dimethylhexadecylamine and 6 to 8 parts of glacial acetic acid, stirring at 60 to 70° C. for 4 to 6 hours, cooling, and removing the solvent by rotary evaporation to obtain the quaternary ammonium salt POSS.

[0016] The invention selects glycidyloxypropyl POSS with a specific viscosity and epoxy equivalent as a raw material, and performs a ring-opening addition reaction with N,N-dimethylhexadecylamine to synthesize a quaternary ammonium salt POSS with a quaternary ammonium salt group on the side chain. Simultaneously, since the amount of N,N-dimethylhexadecylamine used is small, the quaternary ammonium salt POSS also contains epoxy active groups, thereby obtaining a POSS material with double active groups.

[0017] As a preferred solution, the sodium alginate is carboxylic acid-modified polyethylene glycol-sodium alginate.

[0018] Carboxylic acid-modified polyethylene glycol-sodium alginate provides dynamic hydrogen bonding sites through the sodium alginate main chain and polyethylene glycol flexible side chains, thereby enhancing the chain segment mobility. The sodium alginate main chain can combine with the epoxy group of the quaternary ammonium salt POSS through the carboxyl group to form a dense network, while the polyethylene glycol flexible chain prevents the orderly stacking of sodium alginate molecules, thereby reducing the brittle fracture point. Combined with the siloxane cage structure of the quaternary ammonium salt POSS embedded in the polymer network, it effectively resists external forces, and improves the coating hardness and self-healing ability through synergistic effects.

[0019] As a preferred solution, the drying conditions in step S2 are: temperature of 30-40° C. and time of 20-24 h.

[0020] As a preferred solution, the step of in situ growth of nano-titanium dioxide includes: first preparing peroxytitanic acid colloid using titanium sulfate, deionized water, ammonia water and hydrogen peroxide; compounding the peroxytitanic acid colloid with a POSS / sodium alginate coating to achieve in situ growth of nano-titanium dioxide, thereby obtaining a self-repairing display screen protective coating based on nanomaterials.

[0021] As a preferred solution, the preparation steps of the peroxytitanic acid colloid include: adding 2 to 4 parts of titanium sulfate and 4 to 6 parts of ammonia water to 10 to 20 parts of deionized water and stirring for 20 to 30 minutes, washing the precipitate with deionized water, and then adding it to 8 to 10 parts of hydrogen peroxide solution and stirring for 30 to 40 minutes to obtain peroxytitanic acid colloid.

[0022] As a preferred solution, the composite treatment step includes: adding 2 to 4 parts of peroxytitanic acid colloid to 40 to 50 parts of deionized water and ultrasonically treating for 16 to 20 minutes, then coating it on the surface of the POSS / sodium alginate coating for composite treatment for 4 to 6 hours, washing with water, and constant temperature treatment at 100 to 120°C for 200 to 240 minutes to obtain a self-repairing display screen protective coating based on nanomaterials.

[0023] The invention uses titanium sulfate, deionized water, ammonia water and hydrogen peroxide as raw materials to prepare peroxytitanic acid colloid, then dilutes the colloid and coats it on the surface of POSS / sodium alginate coating for compounding, and finally promotes the hydrolysis of the peroxytitanic acid colloid through high-temperature treatment to achieve in-situ growth of nano-titanium dioxide in the coating material.

[0024] The second aspect of the present invention provides a self-repairing display screen protective coating based on nanomaterials prepared by the preparation method described in the first aspect. Compared with the prior art, the advantages and beneficial effects of the present invention are: 1. The quaternary ammonium salt POSS of the present invention contains both quaternary ammonium groups and epoxy-active groups, wherein the quaternary ammonium groups bring positive charge to the POSS material, and the positively charged quaternary ammonium groups contact the negatively charged groups (such as carboxyl groups) of carboxylic acid-modified polyethylene glycol-sodium alginate to generate electrostatic interaction, and the positively charged quaternary ammonium salt POSS will be rapidly attracted to the negatively charged sodium alginate chain, and form micro-nano-sized aggregates through the synergistic effect of intramolecular and intermolecular cross-linking, thereby realizing self-assembly to obtain microgels, and the free quaternary ammonium salt POSS and sodium alginate chain segments near the damaged surface have high mobility, and the two have a strong tendency to recombine, and the free positively charged POSS will seek and recombine to the free negatively charged sodium alginate sites on the fracture surface, thereby realizing self-repair of the coating.

[0025] 2. The carboxylic acid-modified polyethylene glycol-sodium alginate of the present invention provides dynamic hydrogen bonding sites through the sodium alginate main chain and the polyethylene glycol flexible side chain, thereby enhancing the chain segment mobility. The sodium alginate main chain can combine with the epoxy group of the quaternary ammonium salt POSS through the carboxyl group to form a dense network, while the polyethylene glycol flexible chain prevents the orderly accumulation of sodium alginate molecules, thereby reducing the brittle fracture point. The siloxane cage structure of the quaternary ammonium salt POSS is embedded in the polymer network to effectively resist external forces, thereby improving the coating hardness and self-repairing ability through synergistic effects.

[0026] 3. The present invention introduces peroxytitanic acid colloid, a precursor of titanium dioxide, into the POSS / sodium alginate coating. The peroxytitanic acid colloid can enter the interior of the POSS / sodium alginate coating and promotes the hydrolysis of peroxytitanic acid through high-temperature treatment, thereby achieving in-situ growth of titanium dioxide inside the coating, establishing coordination bonds between the oxygen-containing groups of the coating polymer and the titanium atoms on the surface of the titanium dioxide, achieving further cross-linking of the coating, improving the interaction between the coating and the substrate, and within the coating, increasing its stability, and significantly increasing the hardness of the coating. DETAILED DESCRIPTION

[0027] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0028] The sources of some components in the Examples and Comparative Examples are as follows: Glycidyl ether oxypropyl POSS, viscosity 4800 cps, epoxy equivalent weight 167 g / eq, purchased from Zhengzhou Alpha Chemical Co., Ltd.; N,N-Dimethylhexadecylamine, product number N159432, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.; Carboxylic acid-modified polyethylene glycol-sodium alginate was purchased from Delta Bio; Titanium sulfate, CAS No. 13693-11-3, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; Hydrogen peroxide solution, product number H112515, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0029] Example 1 This embodiment provides a method for preparing a self-repairing display screen protective coating based on nanomaterials, comprising the following steps: S1: 50 parts of quaternary ammonium salt POSS were added to 100 parts of isopropanol and mixed evenly, and then 100 parts of a 10% mass concentration of carboxylic acid-modified polyethylene glycol-sodium alginate aqueous solution were added and stirred thoroughly to obtain a gel; S2: The gel was cast on the surface of the display substrate and dried (temperature 40 ° C, time 20 h) to obtain the POSS / sodium alginate coating; S3: In situ growth of nano-titanium dioxide on the POSS / sodium alginate coating: 4 parts of titanium sulfate and 6 parts of ammonia water were added to 20 parts of deionized water and stirred for 30 minutes. The precipitate was washed with deionized water and then added to 10 parts of hydrogen peroxide solution and stirred for 40 minutes to obtain peroxytitanic acid colloid; 4 parts of peroxytitanic acid colloid were added to 50 parts of deionized water and ultrasonically treated for 20 minutes, and then coated on the surface of the POSS / sodium alginate coating for 6 hours, washed with water, and treated at a constant temperature at 120°C for 200 minutes to obtain a self-repairing display screen protective coating based on nanomaterials.

[0030] Preparation of quaternary ammonium salt POSS: In parts by weight, 40 parts of glycidyloxypropyl POSS (viscosity 4800 cps, epoxy equivalent 167 g / eq), 60 parts of toluene and 100 parts of isopropanol were mixed and stirred for 80 minutes, and then 26 parts of N,N-dimethylhexadecylamine and 8 parts of glacial acetic acid were added. The mixture was stirred at 70°C for 4 hours, cooled, and the solvent was removed by rotary evaporation to obtain quaternary ammonium salt POSS.

[0031] Example 2 This embodiment provides a method for preparing a self-repairing display screen protective coating based on nanomaterials, comprising the following steps: S1: 40 parts of quaternary ammonium salt POSS were added to 80 parts of isopropanol and mixed evenly, and then 90 parts of 8% by mass concentration of carboxylic acid-modified polyethylene glycol-sodium alginate aqueous solution were added and stirred thoroughly to obtain a gel; S2: The gel was cast on the surface of the display substrate and dried (temperature 30°C, time 24h) to obtain a POSS / sodium alginate coating; S3: In situ growth of nano-titanium dioxide on the POSS / sodium alginate coating: 2 parts of titanium sulfate and 4 parts of ammonia water were added to 10 parts of deionized water and stirred for 20 minutes. The precipitate was washed with deionized water and then added to 8 parts of hydrogen peroxide solution and stirred for 30 minutes to obtain peroxytitanic acid colloid; 2 parts of peroxytitanic acid colloid were added to 40 parts of deionized water and ultrasonically treated for 16 minutes, and then coated on the surface of the POSS / sodium alginate coating for 4 hours, washed with water, and treated at a constant temperature at 100°C for 240 minutes to obtain a self-repairing display screen protective coating based on nanomaterials.

[0032] Preparation of quaternary ammonium salt POSS: In parts by weight, 30 parts of glycidyloxypropyl POSS (viscosity 4800 cps, epoxy equivalent 167 g / eq), 50 parts of toluene and 90 parts of isopropanol were mixed and stirred for 60 minutes, and then 22 parts of N,N-dimethylhexadecylamine and 6 parts of glacial acetic acid were added. The mixture was stirred at 60°C for 6 hours, cooled, and the solvent was removed by rotary evaporation to obtain quaternary ammonium salt POSS.

[0033] Example 3 This embodiment provides a method for preparing a self-repairing display screen protective coating based on nanomaterials, comprising the following steps: S1: 45 parts of quaternary ammonium salt POSS were added to 90 parts of isopropanol and mixed evenly, and then 95 parts of a 9% by mass concentration carboxylic acid-modified polyethylene glycol-sodium alginate aqueous solution were added and stirred thoroughly to obtain a gel; S2: The gel was cast on the surface of the display substrate and dried (temperature 35 °C, time 22 h) to obtain a POSS / sodium alginate coating; S3: In situ growth of nano-titanium dioxide on the POSS / sodium alginate coating: 3 parts of titanium sulfate and 5 parts of ammonia water were added to 15 parts of deionized water and stirred for 25 minutes. The precipitate was washed with deionized water and then added to 9 parts of hydrogen peroxide solution and stirred for 35 minutes to obtain peroxytitanic acid colloid; 2-4 parts of peroxytitanic acid colloid were added to 45 parts of deionized water and ultrasonically treated for 18 minutes, and then coated on the surface of the POSS / sodium alginate coating for compounding for 5 hours, washed with water, and treated at a constant temperature of 110°C for 220 minutes to obtain a self-repairing display screen protective coating based on nanomaterials.

[0034] Preparation of quaternary ammonium salt POSS: In parts by weight, 35 parts of glycidyloxypropyl POSS (viscosity 4800 cps, epoxy equivalent 167 g / eq), 55 parts of toluene and 95 parts of isopropanol were mixed and stirred for 70 minutes, and then 24 parts of N,N-dimethylhexadecylamine and 7 parts of glacial acetic acid were added. The mixture was stirred at 65°C for 5 hours, cooled, and the solvent was removed by rotary evaporation to obtain quaternary ammonium salt POSS.

[0035] Comparative Example 1 The difference between this comparative example and Example 1 is that glycidyl ether oxypropyl POSS is used instead of quaternary ammonium salt POSS.

[0036] Comparative Example 2 The difference between this comparative example and Example 1 is that commercially available sodium alginate (Product No. S100126) is used instead of carboxylic acid-modified polyethylene glycol-sodium alginate.

[0037] Comparative Example 3 The difference between this comparative example and Example 1 is that the in-situ growth of nano-titanium dioxide in step S3 is not performed.

[0038] Performance Testing The coatings prepared in the above examples and comparative examples were subjected to the following tests: (1) Self-repairing ability test: Install a special copper brush (OSAKA JAPAN OK copper brush) on the wear tester, apply a force of 500gf in the vertical direction, and rub the coating surface 20 times to count the number of scratches. If the number of scratches is ≤5, it is qualified, otherwise it is judged as unqualified.

[0039] (2) Hardness test: Test in accordance with the requirements of GB / T 6739-2022 Paints and varnishes - Determination of film hardness by pencil method.

[0040] (3) Light transmittance test: Test in accordance with the requirements of ASTM D1003 Standard Test Method for Haze and Total Light Transmittance of Transparent Plastics.

[0041] Table 1 Performance test results

[0042] It can be seen from the above performance test results that the comprehensive performance of the coatings of Examples 1-3 is the most outstanding, with good self-repairing ability and a hardness of 8H; this is mainly because glycidyl ether oxypropyl POSS is used as a raw material to prepare quaternary ammonium salt POSS, and it works together with carboxylic acid-modified polyethylene glycol-sodium alginate to form a gel, which is then poured on the surface of the display substrate to obtain a POSS / sodium alginate coating, and finally a self-repairing display protective coating based on nanomaterials is obtained by in situ growth of nano titanium dioxide, which achieves good self-repairing ability and significantly improves the coating hardness.

[0043] Compared with Example 1, Comparative Example 1 uses glycidyloxypropyl POSS instead of quaternary ammonium salt POSS, which lacks positively charged quaternary ammonium salt groups and is difficult to achieve self-assembly with sodium alginate, so the self-repairing ability of the coating deteriorates and the hardness decreases; Compared with Example 1, Comparative Example 2 uses commercially available sodium alginate (Article No. S100126) instead of carboxylic acid-modified polyethylene glycol-sodium alginate. Due to the lack of synergistic effect of polyethylene glycol flexible side chains, the self-repairing ability of the coating deteriorates and the hardness decreases; Compared with Example 1, in Comparative Example 3, nano-titanium dioxide is not grown in situ, and the cross-linking promoting effect of titanium dioxide is lacking, so the hardness of the coating decreases.

Claims

1. A method for preparing a self-repairing display screen protective coating based on nanomaterials, characterized in that: The following steps are involved: S1: Add quaternary ammonium salt POSS to isopropyl alcohol and mix well, then add sodium alginate aqueous solution and stir thoroughly to obtain a gel; S2: Casting the gel on the display substrate surface and obtaining a POSS / sodium alginate coating after drying; S3: In situ growth of nano-TiO2 on the POSS / sodium alginate coating to obtain a nanomaterial-based self-repairing display protective coating; The preparation method of the quaternary ammonium salt POSS comprises: using N,N-dimethylhexadecylamine and glacial acetic acid to perform quaternization treatment on a POSS material to obtain the quaternary ammonium salt POSS.

2. The method for preparing a self-repairing display screen protective coating based on nanomaterials according to claim 1, characterized in that: The weight parts of the components in step S1 include: 40-50 parts of quaternary ammonium salt POSS, 80-100 parts of isopropyl alcohol, and 90-100 parts of sodium alginate aqueous solution with a mass concentration of 8-10%.

3. The method for preparing a self-repairing display screen protective coating based on nanomaterials according to claim 1, characterized in that: The POSS material is glycidyloxypropyl POSS.

4. The method for preparing a self-repairing display screen protective coating based on nanomaterials according to claim 3, characterized in that: The glycidyl ether oxypropyl POSS has a viscosity of 4800-500 cps and an epoxy equivalent of 165-170 g / eq.

5. The method for preparing a self-repairing display screen protective coating based on nanomaterials according to claim 3, characterized in that: The quaternization treatment step comprises: mixing 30 to 40 parts of glycidyloxypropyl POSS, 50 to 60 parts of toluene and 90 to 100 parts of isopropyl alcohol, stirring for 60 to 80 minutes, then adding 22 to 26 parts of N, N-dimethylhexadecylamine and 6 to 8 parts of glacial acetic acid, stirring at 60 to 70° C. for 4 to 6 hours, cooling, and removing the solvent by rotary evaporation to obtain the quaternary ammonium salt POSS.

6. The method for preparing a self-repairing display screen protective coating based on nanomaterials according to claim 1, characterized in that: The sodium alginate is carboxylic acid modified polyethylene glycol-sodium alginate.

7. The method for preparing a self-repairing display screen protective coating based on nanomaterials according to claim 1, characterized in that: The in-situ growth of nano-titanium dioxide comprises the following steps: firstly preparing peroxytitanic acid colloid using titanium sulfate, deionized water, ammonia water and hydrogen peroxide; and compounding the peroxytitanic acid colloid with a POSS / sodium alginate coating to achieve in-situ growth of nano-titanium dioxide, thereby obtaining a self-repairing display screen protective coating based on nanomaterials.

8. The method for preparing a self-repairing display screen protective coating based on nanomaterials according to claim 1, characterized in that: The preparation steps of the peroxytitanic acid colloid include: adding 2 to 4 parts of titanium sulfate and 4 to 6 parts of ammonia water to 10 to 20 parts of deionized water and stirring for 20 to 30 minutes, washing the precipitate with deionized water, and then adding it to 8 to 10 parts of hydrogen peroxide solution and stirring for 30 to 40 minutes to obtain the peroxytitanic acid colloid.

9. The method for preparing a self-repairing display screen protective coating based on nanomaterials according to claim 1, characterized in that: The composite treatment step includes: adding 2 to 4 parts of peroxytitanic acid colloid to 40 to 50 parts of deionized water and ultrasonically treating for 16 to 20 minutes, then coating it on the surface of the POSS / sodium alginate coating for composite treatment for 4 to 6 hours, washing with water, and constant temperature treatment at 100 to 120° C. for 200 to 240 minutes to obtain a self-repairing display screen protective coating based on nanomaterials.

10. A self-repairing display screen protective coating based on nanomaterials, characterized in that: Prepared according to the method according to any one of claims 1 to 9.

Images