A method for preparing an antistatic mobile phone screen protector

Abstract

This invention discloses a method for preparing an antistatic mobile phone screen protector, belonging to the field of mobile phone screen protector technology. The steps are as follows: Silver nanowires are treated with a silane coupling agent KH570 to obtain pretreated silver nanowires; polymethyl methacrylate, functional additives, and pretreated silver nanowires are mixed, and then melt-extruded, cast, stretched, heat-treated, and cut to obtain the mobile phone screen protector. This invention uses PMMA as the matrix. PMMA has high transparency and is easy to process. By adding functional additives and silver nanowires to the matrix, a synergistic effect is achieved, allowing for a significant improvement in antistatic properties with only a small amount added, without significantly affecting the transparency of PMMA. This results in a screen protector that retains high definition while maintaining good antistatic properties. Furthermore, the functional additives also impart certain antibacterial properties to the screen protector, improving the safety of its use.

Description

Technical Field

[0001] This invention belongs to the field of mobile phone screen protector technology, specifically, it relates to a method for preparing an antistatic mobile phone screen protector. Background Technology

[0002] With the widespread use of mobile phones and other digital products, the demand for mobile phone screen protectors is increasing. Mobile phone screen protectors are plastic films used to protect mobile phone screens, and as their use becomes more widespread, functional screen protectors are receiving more and more attention.

[0003] Mobile phones generate static electricity during use, which can affect electrostatic adsorption, causing dust to accumulate and impacting touchscreen sensitivity. Therefore, anti-static functional screen protectors have emerged. For example, Chinese invention patent CN109054058A discloses a method for preparing a mobile phone screen protector, including the following steps: extruding and granulating 80-100 parts by weight of polyester masterbatch and 10-20 parts by weight of functional filler to obtain a functional masterbatch, wherein the functional filler is polyaniline-coated graphene and modified zinc oxide microparticles; melting and extruding the polyester base material and the functional masterbatch, casting, stretching and shaping, heat treating, and cutting to obtain a mobile phone screen protector, wherein the functional masterbatch is obtained by extruding and granulating 80-100 parts by weight of polyester masterbatch and 10-20 parts by weight of functional filler. Although this patent enables the screen protector to have anti-static properties, the use of graphene and zinc oxide as fillers, with graphene being black, significantly affects the transparency of the polyester base material, failing to meet the high-definition requirements of the screen protector. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing an antistatic mobile phone screen protector.

[0005] The mobile phone screen protector of this invention uses PMMA as a substrate. PMMA has the characteristics of high transparency and easy processing. By adding functional additives and silver nanowires to the substrate, they have a synergistic effect. A small amount of these additives can significantly improve the antistatic properties without greatly affecting the transparency of PMMA. This allows the protector to have good antistatic properties while still maintaining high-definition characteristics. In addition, the functional additives can also give the protector certain antibacterial properties, improving the safety of using the mobile phone screen protector.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A method for preparing an antistatic mobile phone screen protector, comprising the following steps:

[0008] Silver nanowires (average radius 30 nm) were mixed with an ethanol aqueous solution (volume fraction 50%) at a solid-liquid ratio of 1 g: 20 mL. The mixture was sonicated for 15 min, and then silane coupling agent KH570 was added. The mixture was heated to 70 °C and stirred for 2 h. After filtration, the mixture was washed with ethanol 3-4 times and then dried in a vacuum oven to constant weight to obtain pretreated silver nanowires.

[0009] A mobile phone screen protector is obtained by mixing polymethyl methacrylate (PMMA), functional additives and pretreated silver nanowires, followed by melt extrusion, casting, stretching and shaping, heat treatment and cutting.

[0010] Furthermore, the amount of silane coupling agent KH570 used is twice the mass of the silver nanowires.

[0011] Furthermore, the mass ratio of the polymethyl methacrylate, functional additives, and pretreated silver nanowires is 100:3-4:0.6-0.7.

[0012] After being treated with the silane coupling agent KH570, silver nanowires can improve their interfacial compatibility with the PMMA matrix, promote uniform dispersion in the film, thereby forming a conductive network structure within the film and enhancing the antistatic properties of the film.

[0013] Furthermore, the functional additive is prepared by the following steps:

[0014] S1. The reaction apparatus was a three-necked flask equipped with a reflux condenser, a stirrer, and a nitrogen delivery tube. 3-oxopentanediamine and anhydrous dichloromethane were added to the apparatus, and nitrogen gas was introduced and continuously purged for 30 minutes. Then, methacryloyl chloride was added dropwise using a constant-pressure dropping funnel (ensuring an anaerobic environment in the reaction system), with a dropping rate controlled at 0.1 mL / min. The reaction was carried out under continuous nitrogen protection and stirring for 5 hours under reflux. After the reaction, the mixture was extracted three times with saturated sodium bicarbonate solution and distilled water, respectively. The organic layer was collected, dried over anhydrous calcium carbonate, and purified by column chromatography after the solvent was evaporated. Dichloromethane was used as the eluent. Finally, dichloromethane was removed by rotary evaporation to obtain the intermediate product. The ratio of 3-oxopentanediamine, anhydrous dichloromethane, and methacryloyl chloride was 0.011 mol: 50 mL: 0.01 mol.

[0015] The -NH2 group on the 3-oxopentanediamine molecule undergoes a substitution reaction with acryloyl chloride. By controlling the molar ratio of the two to be close to 1:1 and with a slight excess of 3-oxopentanediamine, only the -NH2 group at the end of the 3-oxopentanediamine participates in the reaction, yielding an intermediate product. The reaction process is shown below:

[0016]

[0017] S2. Add 4-pyridinecarboxylic acid, triethylamine (acid-binding agent), and anhydrous dichloromethane to a three-necked flask equipped with a stirrer, reflux condenser, and nitrogen delivery tube. Purge with nitrogen for 10 minutes, then add the intermediate product and DIC (N,N-diisopropylcarbodiimide, dehydrating agent). Stir and react for 3 hours at room temperature under N2 protection. After the reaction is complete, extract three times with hot distilled water (60-70℃). Take the organic layer, dry it with anhydrous calcium carbonate, evaporate the solvent, and purify by column chromatography with dichloromethane as the eluent. Finally, remove the dichloromethane by rotary evaporation to obtain the functional monomer. The ratio of 4-pyridinecarboxylic acid, triethylamine, anhydrous dichloromethane, intermediate product, and DIC is 0.1 mol: 10.1 g: 300 mL: 15.8 g: 12.6 g.

[0018] The -COOH group on the 4-pyridinecarboxylic acid molecule undergoes a condensation reaction with the -NH2 group on the intermediate product molecule to obtain a functional monomer containing an unsaturated carbon-carbon double bond. The reaction process is shown below:

[0019]

[0020] S3. Add the functional monomer, methyl methacrylate, AIBN (azobisisobutyronitrile), and DMF (N,N-dimethylformamide) solvent to a dry three-necked flask. After adding the reactants, purge with nitrogen for 10 minutes and then evacuate. Repeat this process three times (ensuring no air in the system). Heat and stir in an oil bath at 90°C for 20 hours. After the reaction is complete, a viscous liquid crude product is obtained. Add distilled water to the crude product to precipitate the solid. Filter the solid, collect it, and dry it under vacuum. Place it in a Soxhlet extractor and wash it with dichloromethane for 24 hours. Finally, dry it thoroughly to obtain the polymer. The ratio of functional monomer, methyl methacrylate, AIBN, DMF, and distilled water is 0.7g:23g:0.2g:150mL:1000mL.

[0021] Under conditions where AIBN is used as an initiator, functional monomers and methyl methacrylate undergo a polymerization reaction to generate block polymethyl methacrylate polymers. The reaction process is shown below.

[0022]

[0023] S4. Add the polymer and chloroform to a three-necked flask equipped with a stirrer and a reflux condenser, stir until completely dissolved, then add bromobutane, heat to 70°C, and reflux at this temperature for 12 hours. After the reaction is complete, quench the reaction with excess methanol, filter and collect the solid product, and dry thoroughly to obtain the functional additive; the ratio of polymer, chloroform and bromobutane is 1g:10mL:20mL.

[0024] The tertiary nitrogen groups on the molecular side chains of the polymer undergo alkylation under the action of bromobutane to form quaternary ammonium salt groups. The reaction process is shown below:

[0025]

[0026] The obtained functional additive is a block-type polymethyl methacrylate polymer. Therefore, the functional additive has good compatibility with PMMA and can be uniformly dispersed in the PMMA matrix. From a molecular structure perspective, the side chains of the functional additive contain several amide bonds, ether bonds, and ammonium cations. The nitrogen in the amide bond and the oxygen in the ether bond carry lone pair electrons, thus having the ability to accept protons. This allows for electrostatic dissipation through internal proton transfer. The ammonium cations can increase the charge density of the film and promote charge transfer, thereby exhibiting good antistatic properties. Therefore, the functional additive can enhance the antistatic properties of the film through multiple mechanisms. In addition, the quaternary ammonium salt groups it contains are safe and efficient antibacterial components, which can endow the mobile phone screen protector with certain antibacterial properties and improve the safety of using the mobile phone screen protector.

[0027] It should be further explained that the functional additives, when used in conjunction with silver nanowires, have a synergistic effect. A small amount can significantly improve the antistatic properties without greatly affecting the transparency of PMMA, thus enabling the protective film to maintain high-definition characteristics while possessing good antistatic properties.

[0028] The beneficial effects of this invention are:

[0029] The mobile phone screen protector of this invention uses PMMA as a substrate. PMMA has the characteristics of high transparency and easy processing. By adding functional additives and silver nanowires to the substrate, they have a synergistic effect. A small amount of these additives can significantly improve the antistatic properties without greatly affecting the transparency of PMMA. This allows the protector to have good antistatic properties while still maintaining high-definition characteristics. In addition, the functional additives can also give the protector certain antibacterial properties, improving the safety of using the mobile phone screen protector. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] Preparation of functional additives:

[0033] S1. The reaction apparatus is a three-necked flask equipped with a reflux condenser, a stirrer, and a nitrogen delivery tube. 0.11 mol of 3-oxopramethylenediamine and 500 mL of anhydrous dichloromethane are added to the apparatus. Nitrogen gas is introduced and continuously introduced for 30 min. Then, 0.1 mol of methacryloyl chloride is added dropwise using a constant pressure dropping funnel (to ensure an anaerobic environment in the reaction system). The dropping rate is controlled at 0.1 mL / min. The reaction is carried out under continuous nitrogen protection and stirring for 5 h under reflux. After the reaction is completed, the mixture is extracted three times with saturated sodium bicarbonate solution and distilled water, respectively. The organic layer is collected, dried over anhydrous calcium carbonate, and purified by column chromatography after the solvent is evaporated. The eluent is dichloromethane. Finally, the dichloromethane is removed by rotary evaporation to obtain the intermediate product.

[0034] S2. Add 0.1 mol of 4-pyridinecarboxylic acid, 10.1 g of triethylamine (acid-binding agent), and 300 mL of anhydrous dichloromethane to a three-necked flask equipped with a stirrer, a reflux condenser, and a nitrogen delivery tube. Purge with nitrogen for 10 min, then add 15.8 g of intermediate product and 12.6 g of DIC (N,N-diisopropylcarbodiimide, dehydrating agent). Stir the reaction at room temperature and under N2 protection for 3 h. After the reaction is complete, extract three times with hot distilled water (temperature 60-70℃). Take the organic layer, dry it with anhydrous calcium carbonate, evaporate the solvent, and then purify it by column chromatography with dichloromethane as the eluent. Finally, remove the dichloromethane by rotary evaporation to obtain the functional monomer.

[0035] S3. Add 0.7g of functional monomer, 23g of methyl methacrylate, 0.2g of AIBN (azobisisobutyronitrile), and 150mL of DMF (N,N-dimethylformamide) solvent to a dry three-necked flask. After adding the reactants, purge with nitrogen for 10min and then evacuate. Repeat this process three times (to ensure that there is no air in the system). Heat and stir in an oil bath at 90℃ for 20h. After the reaction is complete, a viscous liquid crude product is obtained. Add 1000mL of distilled water to the crude product to precipitate the solid. Filter the solid, collect it, dry it under vacuum, and place it in a Soxhlet extractor. Elute with dichloromethane as solvent for 24h. Finally, dry thoroughly to obtain the polymer.

[0036] S4. Add 10g of polymer and 100mL of chloroform to a three-necked flask equipped with a stirrer and a reflux condenser. Stir until completely dissolved, then add 200mL of bromobutane. Heat to 70℃ and reflux at this temperature for 12h. After the reaction is complete, quench the reaction with excess methanol, filter and collect the solid product, and dry thoroughly to obtain the functional additive.

[0037] Example 2

[0038] Preparation of functional additives:

[0039] S1. The reaction apparatus is a three-necked flask equipped with a reflux condenser, a stirrer, and a nitrogen delivery tube. 0.11 mol of 3-oxopramethylenediamine and 500 mL of anhydrous dichloromethane are added to the apparatus. Nitrogen gas is introduced and continuously introduced for 30 min. Then, 0.1 mol of methacryloyl chloride is added dropwise using a constant pressure dropping funnel (to ensure an anaerobic environment in the reaction system). The dropping rate is controlled at 0.1 mL / min. The reaction is carried out under continuous nitrogen protection and stirring for 5 h under reflux. After the reaction is completed, the mixture is extracted three times with saturated sodium bicarbonate solution and distilled water, respectively. The organic layer is collected, dried over anhydrous calcium carbonate, and purified by column chromatography after the solvent is evaporated. The eluent is dichloromethane. Finally, the dichloromethane is removed by rotary evaporation to obtain the intermediate product.

[0040] S2. Add 0.1 mol of 4-pyridinecarboxylic acid, 10.1 g of triethylamine (acid-binding agent), and 300 mL of anhydrous dichloromethane to a three-necked flask equipped with a stirrer, a reflux condenser, and a nitrogen delivery tube. Purge with nitrogen for 10 min, then add 15.8 g of intermediate product and 12.6 g of DIC (N,N-diisopropylcarbodiimide, dehydrating agent). Stir the reaction at room temperature and under N2 protection for 3 h. After the reaction is complete, extract three times with hot distilled water (temperature 60-70℃). Take the organic layer, dry it with anhydrous calcium carbonate, evaporate the solvent, and then purify it by column chromatography with dichloromethane as the eluent. Finally, remove the dichloromethane by rotary evaporation to obtain the functional monomer.

[0041] S3. Add 0.7g of functional monomer, 23g of methyl methacrylate, 0.2g of AIBN (azobisisobutyronitrile), and 150mL of DMF (N,N-dimethylformamide) solvent to a dry three-necked flask. After adding the reactants, purge with nitrogen for 10min and then evacuate. Repeat this process three times (to ensure that there is no air in the system). Heat and stir in an oil bath at 90℃ for 20h. After the reaction is complete, a viscous liquid crude product is obtained. Add 1000mL of distilled water to the crude product to precipitate the solid. Filter the solid, collect it, dry it under vacuum, and place it in a Soxhlet extractor. Elute with dichloromethane as solvent for 24h. Finally, dry thoroughly to obtain the polymer.

[0042] S4. Add 10g of polymer and 100mL of chloroform to a three-necked flask equipped with a stirrer and a reflux condenser. Stir until completely dissolved, then add 200mL of bromobutane. Heat to 70℃ and reflux at this temperature for 12h. After the reaction is complete, quench the reaction with excess methanol, filter and collect the solid product, and dry thoroughly to obtain the functional additive.

[0043] Example 3

[0044] A method for preparing an antistatic mobile phone screen protector, comprising the following steps:

[0045] 10g of silver nanowires (average radius of 30nm) were mixed with 200mL of ethanol aqueous solution (volume fraction of 50%), sonicated for 15min, and then 20g of silane coupling agent KH570 was added. The mixture was heated to 70℃ and stirred for 2h. After filtration, the mixture was washed three times with ethanol and then dried in a vacuum oven to constant weight to obtain pretreated silver nanowires.

[0046] 1000g of polymethyl methacrylate (PMMA), 30g of the functional additives prepared in Example 1, and 6g of pretreated silver nanowires were mixed and then subjected to melt extrusion, casting, stretching and shaping, heat treatment, and cutting to obtain a mobile phone screen protector.

[0047] Example 4

[0048] A method for preparing an antistatic mobile phone screen protector, comprising the following steps:

[0049] 10g of silver nanowires (average radius of 30nm) were mixed with 200mL of ethanol aqueous solution (volume fraction of 50%), sonicated for 15min, and then 20g of silane coupling agent KH570 was added. The mixture was heated to 70℃ and stirred for 2h. After filtration, the mixture was washed 4 times with ethanol and then dried in a vacuum oven to constant weight to obtain pretreated silver nanowires.

[0050] 1000g of polymethyl methacrylate (PMMA), 35g of the functional additives prepared in Example 2, and 6.5g of pretreated silver nanowires were mixed and then melt-extruded, cast, stretched, heat-treated, and cut to obtain a mobile phone screen protector.

[0051] Example 5

[0052] A method for preparing an antistatic mobile phone screen protector, comprising the following steps:

[0053] 10g of silver nanowires (average radius of 30nm) were mixed with 200mL of ethanol aqueous solution (volume fraction of 50%), sonicated for 15min, and then 20g of silane coupling agent KH570 was added. The mixture was heated to 70℃ and stirred for 2h. After filtration, the mixture was washed 4 times with ethanol and then dried in a vacuum oven to constant weight to obtain pretreated silver nanowires.

[0054] 1000g of polymethyl methacrylate (PMMA), 40g of the functional additives prepared in Example 1, and 7g of pretreated silver nanowires were mixed and then subjected to melt extrusion, casting, stretching and shaping, heat treatment, and cutting to obtain a mobile phone screen protector.

[0055] The protective films obtained in Examples 3-5 were cut into test sample sizes and subjected to the following performance tests:

[0056] Mechanical properties were tested according to national standard GB / T13022-1991; resistivity was tested according to national standard GB / T1410-2006, and a wear test was conducted on the sample surface using a friction fastness tester, with 1000 rub cycles, and the resistivity was measured; antibacterial properties were tested according to industry standard QB / T2591-2003; the transmittance of the protective film at a wavelength of 550nm was measured.

[0057] The measured results are shown in the table below:

[0058]

[0059] As shown in the table above, the mobile phone screen protector obtained by this invention has the required mechanical properties, as well as superior antistatic and antibacterial properties. In addition, after 1000 rubs, the antistatic properties remain good, indicating that it has durable antistatic properties. Furthermore, the mobile phone screen protector of this invention has a light transmittance of >90%, which indicates good optical transparency.

[0060] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0061] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. A method for preparing an antistatic mobile phone screen protector, characterized in that, The steps are as follows: The first step is to treat silver nanowires with silane coupling agent KH570 to obtain pretreated silver nanowires. The second step involves mixing polymethyl methacrylate, functional additives, and pretreated silver nanowires, followed by melt extrusion, casting, stretching and shaping, heat treatment, and cutting to obtain a mobile phone screen protector. The functional additive is prepared through the following steps: S1. The reaction apparatus was a three-necked flask equipped with a reflux condenser, a stirrer, and a nitrogen delivery tube. 3-oxopramethylenediamine and anhydrous dichloromethane were added to the apparatus, and nitrogen gas was introduced and continuously introduced for 30 min. Then, methacryloyl chloride was added dropwise using a constant pressure dropping funnel at a rate of 0.1 mL / min. The reaction was carried out under continuous nitrogen protection and stirring for 5 h. After the reaction was completed, the mixture was extracted three times with saturated sodium bicarbonate solution and distilled water, respectively. The organic layer was collected, dried over anhydrous calcium carbonate, and purified by column chromatography after the solvent was evaporated. The eluent was dichloromethane. Finally, the dichloromethane was removed by rotary evaporation to obtain the intermediate product. S2. Add 4-pyridinecarboxylic acid, triethylamine and anhydrous dichloromethane to a three-necked flask equipped with a stirrer, a reflux condenser and a nitrogen delivery tube. Purge with nitrogen for 10 min, then add the intermediate and DIC. Stir the reaction at room temperature and under N2 protection for 3 h. After the reaction is complete, extract three times with hot distilled water, take the organic layer, dry it with anhydrous calcium carbonate, evaporate the solvent and purify it by column chromatography with dichloromethane as the eluent. Finally, remove the dichloromethane by rotary evaporation to obtain the functional monomer. S3. Add the functional monomer, methyl methacrylate, AIBN and DMF solvent to a dry three-necked flask. After adding the reactants, purge with nitrogen for 10 min and then evacuate. Repeat this operation three times. Heat and stir in an oil bath at 90°C for 20 h. After the reaction is complete, a viscous liquid crude product is obtained. Add distilled water to the crude product to precipitate the precipitate. Filter the precipitate, collect the solid, dry it under vacuum, and place it in a Soxhlet extractor. Wash with dichloromethane solvent for 24 h. Finally, dry thoroughly to obtain the polymer. S4. Add the polymer and chloroform to a three-necked flask equipped with a stirrer and a reflux condenser, stir until completely dissolved, then add bromobutane, heat to 70°C, and reflux at this temperature for 12 hours. After the reaction is complete, quench the reaction with excess methanol, filter and collect the solid product, and dry thoroughly to obtain the functional additive.

2. The method for preparing an antistatic mobile phone screen protector according to claim 1, characterized in that, The specific steps of the first step are as follows: after mixing silver nanowires with an ethanol aqueous solution at a solid-liquid ratio of 1g:20mL, sonicate for 15min, add silane coupling agent KH570, heat to 70℃ and stir for 2h, filter, wash with ethanol 3-4 times, and dry in a vacuum oven to constant weight to obtain pretreated silver nanowires.

3. The method for preparing an antistatic mobile phone screen protector according to claim 2, characterized in that, The amount of silane coupling agent KH570 used was twice the mass of the silver nanowires, and the volume fraction of the ethanol aqueous solution was 50%.

4. The method for preparing an antistatic mobile phone screen protector according to claim 1, characterized in that, The mass ratio of the polymethyl methacrylate, functional additives, and pretreated silver nanowires is 100:3-4:0.6-0.

7.

5. The method for preparing an antistatic mobile phone screen protector according to claim 1, characterized in that, In step S1, the ratio of 3-oxopramethylenediamine, anhydrous dichloromethane, and acryloyl chloride is 0.011 mol: 50 mL: 0.01 mol.

6. The method for preparing an antistatic mobile phone screen protector according to claim 1, characterized in that, In step S2, the temperature is 60-70℃, and the ratio of the amounts of 4-pyridinecarboxylic acid, triethylamine, anhydrous dichloromethane, intermediate product, and DIC is 0.1mol:10.1g:300mL:15.8g:12.6g.

7. The method for preparing an antistatic mobile phone screen protector according to claim 1, characterized in that, In step S3, the ratio of the amount of functional monomer, methyl methacrylate, AIBN, DMF and distilled water is 0.7g:23g:0.2g:150mL:1000mL.

8. The method for preparing an antistatic mobile phone screen protector according to claim 1, characterized in that, In step S4, the ratio of the polymer, chloroform, and bromobutane is 1g:10mL:20mL.

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