Preparation method and application of anti-warping buffer protective film

Abstract

The invention relates to a preparation method and application of an anti-warping buffer protective film, and belongs to the technical field of high polymer materials. The anti-warping buffer protective film sequentially comprises a protective layer, a base material layer and a buffer layer from top to bottom, the protective layer is formed by coating a protective film glue solution on the upper layer of the base material layer and curing the protective film glue solution, the buffer layer is formed by coating a buffer layer glue solution on the lower layer of the base material layer and curing the buffer layer glue solution, and the base material layer is a PET base film; the buffer layer glue solution is prepared from the following raw materials in parts by weight: 10 to 70 parts of elastic light-cured resin, 0.05 to 1 part of an auxiliary agent and 1 to 5 parts of a photoinitiator; the protective film glue solution comprises the following raw materials in parts by weight: 20-45 parts of acrylic resin, 4-6 parts of a photoinitiator, 100-250 parts of a solvent, 0.05-0.5 part of a flatting agent and 1-5 parts of an anti-warping curing agent, the anti-warping buffer protective film prepared by the invention not only has an excellent anti-warping effect, but also has good impact resistance and chemical corrosion resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a preparation method and application of an anti-warping buffer protective film. Background Art

[0002] With the rapid development of science and technology, people's living standards are constantly improving, and electronic devices are becoming more and more popular. At present, most electronic devices use touch screens for human-computer interaction. Since the screens are fragile and easy to scratch, a layer of protective film is usually attached to the surface of the electronic device to prevent the surface of the device from being scratched by hard objects.

[0003] However, there are two main types of protective films. One is a single-layer structure made of plastic material, which is light-transmitting and soft, but has a high degree of deformation and when the screen protective film is damaged, a new protective film must be re-applied, which increases the trouble and cost of the user and burdens the environment. The other tempered film has a good anti-scratch effect, but is very brittle. After long-term use, fragments will appear on the corners, which can easily scratch the skin and cause human harm. In addition, the protective film is easily warped at the edges due to environmental factors, affecting normal use and appearance. Ordinary protective films play a buffering role to a certain extent, but in actual applications, they cannot meet market demand. Therefore, the research and development of protective films with excellent anti-warping buffering has important practical significance and application value. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a method for preparing an anti-warping buffer protective film and an application thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] An anti-warping buffer protective film, which comprises a protective layer, a substrate layer and a buffer layer from top to bottom, wherein the protective layer is formed by coating a protective film glue on an upper substrate layer and curing, and the buffer layer is formed by coating a buffer layer glue on a lower substrate layer and curing, and the substrate layer is a PET base film;

[0007] Furthermore, the buffer layer glue comprises the following raw materials in parts by weight: 10-70 parts of elastic light-curable resin, 0.05-1 parts of polyester-modified silicone, and 1-5 parts of benzophenone;

[0008] Furthermore, the elastic light-curable resin is prepared by the following method:

[0009] At room temperature, ethyl acetate, 2-phenoxyethyl acrylate and 1,6-hexanediamine are mixed and reacted for 2-5 hours, and then polyethylene glycol-200 diacrylate and trimethylolpropane triacrylate are added and mixed and reacted for 2-4 hours to obtain an elastic light-curing resin;

[0010] Furthermore, the protective film glue comprises the following raw materials in parts by weight: 20-45 parts of acrylic resin, 4-6 parts of benzophenone, 100-250 parts of ethyl acetate, 0.05-0.5 parts of polydimethylsiloxane, and 1-5 parts of anti-warping curing agent;

[0011] Furthermore, the anti-warping curing agent is prepared by the following method:

[0012] Step A1: 4,4-diaminophenylsulfone and 200 mL of anhydrous ethanol were placed in a beaker, stirred at 60°C, then m-hydroxybenzaldehyde was dispersed in 100 mL of anhydrous ethanol, stirred at 60°C, and then slowly added dropwise to the beaker, the addition was completed within 2 hours, stirred at 60°C for 4 hours, cooled to room temperature, distilled under reduced pressure, dried in a vacuum oven at 60°C for 12 hours, then allyl chloride, potassium carbonate and 8 mL of anhydrous ethanol were added, stirred at 80°C, and reacted for 24 hours to obtain a compound;

[0013] Further, the dosage ratio of 4,4-diaminophenylsulfone, m-hydroxybenzaldehyde, propylene chloride and potassium carbonate is 11.6-13.4 g: 6.1-7.2 g: 1-3 mol: 0.1-0.2 mol;

[0014] Step A2: triethylamine, N-aminopropylmorpholine and 10 mL of dichloromethane were placed in a reaction bottle, mixed, and stirred at room temperature for 20 min. Acryloyl chloride was dispersed in 10 mL of dichloromethane and then added to the reaction bottle. The temperature was controlled to be 0°C, and the reaction was continued for 0.5 h, and then the reaction was continued at room temperature for 8 h, and dried to obtain a morpholine compound.

[0015] Further, the mass ratio of triethylamine, N-aminopropylmorpholine, and acryloyl chloride is 4.1-4.3 g: 0.42-0.53 g: 0.32-0.38 g;

[0016] Step A3: Disperse the compound evenly in deionized water and ammonium persulfate, add the morpholine compound and stir evenly, heat to 70° C. under nitrogen protection for reaction for 4.5 hours, distill under reduced pressure, freeze, and vacuum dry to obtain an anti-warping curing agent;

[0017] Furthermore, the usage ratio of the compound, deionized water, ammonium persulfate, and morpholine compound is 3-5 g: 20 mL: 0.02 g: 5-8 g.

[0018] A method for preparing an anti-warping buffer protective film specifically comprises the following steps:

[0019] S1. Evenly mix acrylic resin, benzophenone, ethyl acetate, polydimethylsiloxane and anti-warping curing agent to prepare a protective film glue solution;

[0020] S2, mixing elastic light-curable resin, polyester-modified silicone and benzophenone uniformly to prepare a buffer layer glue;

[0021] S3. Apply the protective film glue on the PET base film, cure it with UV light, apply the buffer layer glue on the other side of the PET base film, cure it with UV light, and perform laser bevel cutting to make an anti-warping buffer protective film with a thickness of 0.1-0.5mm.

[0022] In a second aspect, the anti-warping buffer protective film obtained by the preparation method is used in protecting the screen of electronic devices.

[0023] Beneficial effects of the present invention:

[0024] The anti-warping buffer protective film of the present invention has a good anti-warping effect, and also has excellent impact resistance and chemical corrosion resistance, thereby extending the service life of the material.

[0025] The anti-warping curing agent prepared by the present invention, with its advantages of macromolecular polymer, exhibits anti-warping performance that surpasses traditional small-molecule anti-warping curing agents. The anti-warping curing agent first utilizes the aldehyde group of m-hydroxybenzaldehyde and the amino group of 4,4-diaminophenylsulfone to react to generate an imine group, and then utilizes the hydroxyl group of m-hydroxybenzaldehyde and the chlorine atom of allyl chloride to react to synthesize a compound; secondly, utilizes the chlorine atom of acryloyl chloride and the amino group of N-aminopropylmorpholine to react to synthesize a morpholine compound; finally, utilizes the carbon-carbon double bond copolymerization of the compound and the morpholine compound to synthesize the anti-warping curing agent. The 4,4-diaminophenylsulfone in the anti-warping curing agent has high temperature resistance and can form a cross-linked network structure with the resin, significantly improving the strength and hardness of the material and effectively reducing the warping phenomenon; the morpholine compound can undergo an embedding reaction on the surface, improve the adhesion and mechanical strength of the resin, and improve the rheological properties of the resin. At the same time, it has good compatibility with the elastomer in the resin, significantly improves the impact resistance under low temperature conditions, and cooperates with the imine group to effectively reduce the warping caused by temperature, avoiding the negative impact on production and product quality; the anti-warping curing agent molecules are evenly distributed in the resin, effectively controlling the shrinkage and expansion of the resin, and further accelerating the curing process. In addition, the imine and morpholine in the anti-warping curing agent can react with the carboxyl group in the acrylic resin to form a uniform cross-linked network, avoiding uneven shrinkage of the resin, thereby reducing the warping phenomenon and significantly improving the thermal stability and chemical corrosion resistance of the material, ensuring that the cured material exhibits better durability and reliability in various applications. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Embodiment 1: An anti-warping buffer protective film, comprising a protective layer, a substrate layer and a buffer layer from top to bottom, wherein the protective layer is formed by coating a protective film adhesive on an upper substrate layer and curing the protective layer, and the buffer layer is formed by coating a buffer layer adhesive on a lower substrate layer and curing the protective layer, wherein the substrate layer is a PET base film;

[0028] The preparation method comprises the following steps:

[0029] S1. Weigh the raw materials by weight, and evenly mix 20 parts of acrylic resin, 4 parts of benzophenone, 100 parts of ethyl acetate, 0.05 parts of polydimethylsiloxane and 1 part of anti-warping curing agent (prepared in this example) to prepare a protective film glue solution;

[0030] S2, weighing raw materials by weight, and evenly mixing 10 parts of elastic light-curable resin (prepared in this embodiment), 0.05 parts of polyester-modified silicone and 1 part of benzophenone to prepare a buffer layer glue;

[0031] S3, coating the protective film glue on the PET base film, curing it with UV light, coating the buffer layer glue on the other side of the PET base film, curing it with UV light, and laser bevel cutting to make an anti-warping buffer protective film with a thickness of 0.1 mm;

[0032] Furthermore, the anti-warping curing agent is prepared by the following method:

[0033] Step A1: put 11.6g 4,4-diaminophenylsulfone and 200mL anhydrous ethanol into a beaker, stir at 60°C, then disperse 6.1g m-hydroxybenzaldehyde in 100mL anhydrous ethanol, stir at 60°C, then slowly add dropwise into the beaker, complete the addition over 2h, stir at 60°C for 4h, cool to room temperature, distill under reduced pressure, dry in a vacuum oven at 60°C for 12h, then add 1mol propylene chloride, 0.1mol potassium carbonate and 8mL anhydrous ethanol, stir at 80°C, react for 24h to obtain a compound;

[0034] Step A2: 4.1 g of triethylamine, 0.42 g of N-aminopropylmorpholine and 10 mL of dichloromethane were placed in a reaction bottle, mixed, and stirred at room temperature for 20 min. Then, 0.32 g of acryloyl chloride was dispersed in 10 mL of dichloromethane and then added to the reaction bottle. The temperature was controlled to be 0°C, and the reaction was continued for 0.5 h, and then the reaction was continued at room temperature for 8 h, and dried to obtain a morpholine compound.

[0035] Step A3: Disperse 3 g of the compound evenly in 20 mL of deionized water and 0.02 g of ammonium persulfate, add 5-8 g of a morpholine compound and stir evenly, heat to 70° C. under nitrogen protection for 4.5 h, distill under reduced pressure, freeze, and vacuum dry to obtain an anti-warping curing agent;

[0036] Furthermore, the elastic light-curable resin is prepared by the following method:

[0037] At room temperature, ethyl acetate, 2-phenoxyethyl acrylate and 1,6-hexanediamine are mixed and reacted for 2-5 hours, and then polyethylene glycol-200 diacrylate and trimethylolpropane triacrylate are added and mixed, and the mixture is reacted for 2-4 hours to obtain an elastic light-curing resin, wherein the mass ratio of ethyl acetate, 2-phenoxyethyl acrylate, 1,6-hexanediamine, polyethylene glycol-200 diacrylate and trimethylolpropane triacrylate is 4:6:1:9.

[0038] Embodiment 2: An anti-warping buffer protective film, comprising a protective layer, a substrate layer and a buffer layer from top to bottom, wherein the protective layer is formed by coating a protective film adhesive on an upper substrate layer and curing the protective layer, and the buffer layer is formed by coating a buffer layer adhesive on a lower substrate layer and curing the protective layer, wherein the substrate layer is a PET base film;

[0039] The preparation method comprises the following steps:

[0040] S1. Weigh the raw materials by weight, and evenly mix 32 parts of acrylic resin, 5 parts of benzophenone, 175 parts of ethyl acetate, 0.25 parts of polydimethylsiloxane and 3 parts of anti-warping curing agent (prepared in this example) to prepare a protective film glue solution;

[0041] S2, weighing raw materials by weight, and evenly mixing 40 parts of elastic light-curable resin (prepared in this embodiment), 0.5 parts of polyester-modified silicone and 3 parts of benzophenone to prepare a buffer layer glue;

[0042] S3, coating the protective film glue on the PET base film, curing it with UV light, coating the buffer layer glue on the other side of the PET base film, curing it with UV light, and laser bevel cutting to make an anti-warping buffer protective film with a thickness of 0.3 mm;

[0043] Furthermore, the anti-warping curing agent is prepared by the following method:

[0044] Step A1: put 12.5g 4,4-diaminophenylsulfone and 200mL anhydrous ethanol into a beaker, stir at 60°C, then disperse 6.6g m-hydroxybenzaldehyde in 100mL anhydrous ethanol, stir at 60°C, then slowly add dropwise into the beaker, complete the addition over 2h, stir at 60°C for 4h, cool to room temperature, distill under reduced pressure, dry in a vacuum oven at 60°C for 12h, then add 2mol propylene chloride, 0.15mol potassium carbonate and 8mL anhydrous ethanol, stir at 80°C, react for 24h to obtain a compound;

[0045] Step A2: 4.2 g of triethylamine, 0.47 g of N-aminopropylmorpholine and 10 mL of dichloromethane were placed in a reaction bottle, mixed, and stirred at room temperature for 20 min. Then, 0.35 g of acryloyl chloride was dispersed in 10 mL of dichloromethane and then added to the reaction bottle. The temperature was controlled to be 0°C, and the reaction was continued for 0.5 h, and then the reaction was continued at room temperature for 8 h, and dried to obtain a morpholine compound;

[0046] Step A3: Disperse 4 g of the compound evenly in 20 mL of deionized water and 0.02 g of ammonium persulfate, add 6.5 g of the morpholine compound and stir evenly, heat to 70° C. under nitrogen protection for 4.5 h, distill under reduced pressure, freeze, and vacuum dry to obtain an anti-warping curing agent;

[0047] Furthermore, the elastic light-curable resin is prepared by the following method:

[0048] At room temperature, ethyl acetate, 2-phenoxyethyl acrylate and 1,6-hexanediamine are mixed and reacted for 2-5 hours, and then polyethylene glycol-200 diacrylate and trimethylolpropane triacrylate are added and mixed, and the mixture is reacted for 2-4 hours to obtain an elastic light-curing resin, wherein the mass ratio of ethyl acetate, 2-phenoxyethyl acrylate, 1,6-hexanediamine, polyethylene glycol-200 diacrylate and trimethylolpropane triacrylate is 4:6:1:9.

[0049] Embodiment 3: A warping-resistant buffer protective film, comprising a protective layer, a substrate layer and a buffer layer from top to bottom, wherein the protective layer is formed by coating a protective film adhesive on an upper substrate layer and curing the protective layer, and the buffer layer is formed by coating a buffer layer adhesive on a lower substrate layer and curing the protective layer, and the substrate layer is a PET base film;

[0050] The preparation method comprises the following steps:

[0051] S1. Weigh the raw materials by weight, and evenly mix 45 parts of acrylic resin, 6 parts of benzophenone, 250 parts of ethyl acetate, 0.5 parts of polydimethylsiloxane and 5 parts of anti-warping curing agent (prepared in this example) to prepare a protective film glue solution;

[0052] S2, weighing raw materials by weight, and evenly mixing 70 parts of elastic light-curable resin (prepared in this embodiment), 1 part of polyester-modified silicone and 5 parts of benzophenone to prepare a buffer layer glue;

[0053] S3, coating the protective film glue on the PET base film, curing it with UV light, coating the buffer layer glue on the other side of the PET base film, curing it with UV light, and laser bevel cutting to make an anti-warping buffer protective film with a thickness of 0.5 mm;

[0054] Furthermore, the anti-warping curing agent is prepared by the following method:

[0055] Step A1: put 13.4g 4,4-diaminophenylsulfone and 200mL anhydrous ethanol into a beaker, stir at 60°C, then disperse 7.2g m-hydroxybenzaldehyde in 100mL anhydrous ethanol, stir at 60°C, then slowly add dropwise into the beaker, complete the addition over 2h, stir at 60°C for 4h, cool to room temperature, distill under reduced pressure, dry in a vacuum oven at 60°C for 12h, then add 3mol propylene chloride, 0.2mol potassium carbonate and 8mL anhydrous ethanol, stir at 80°C, react for 24h to obtain a compound;

[0056] Step A2: 4.3 g of triethylamine, 0.53 g of N-aminopropylmorpholine and 10 mL of dichloromethane were placed in a reaction bottle, mixed, and stirred at room temperature for 20 min. Then, 0.38 g of acryloyl chloride was dispersed in 10 mL of dichloromethane and then added to the reaction bottle. The temperature was controlled to be 0° C., and the reaction was continued for 0.5 h at room temperature for 8 h. The reaction was dried to obtain a morpholine compound.

[0057] Step A3: Disperse 5 g of the compound evenly in 20 mL of deionized water and 0.02 g of ammonium persulfate, add 8 g of the morpholine compound and stir evenly, heat to 70° C. under nitrogen protection for 4.5 h, distill under reduced pressure, freeze, and vacuum dry to obtain an anti-warping curing agent;

[0058] Furthermore, the elastic light-curable resin is prepared by the following method:

[0059] At room temperature, ethyl acetate, 2-phenoxyethyl acrylate and 1,6-hexanediamine are mixed and reacted for 2-5 hours, and then polyethylene glycol-200 diacrylate and trimethylolpropane triacrylate are added and mixed, and the mixture is reacted for 2-4 hours to obtain an elastic light-curing resin, wherein the mass ratio of ethyl acetate, 2-phenoxyethyl acrylate, 1,6-hexanediamine, polyethylene glycol-200 diacrylate and trimethylolpropane triacrylate is 4:6:1:9.

[0060] Comparative Example

[0061] This comparative example is an anti-warping buffer protective film, which is different from Example 3 in that an equal amount of toluene diisocyanate is used to replace the anti-warping curing agent prepared in Example 3, and the rest are the same.

[0062] Performance test: The anti-warping buffer protective films prepared in Examples 1-3 and Comparative Examples 1-2 were cut into standard test sizes, and the warping was tested according to GB / T 25257-2010 "Measurement Method for Warpage of Optical Functional Films", and the impact strength was tested according to GB / T2567-2008, and the chemical corrosion resistance time was tested; the test results are shown in the following table:

[0063]

[0064] It can be seen from the test data in the table that the anti-warping buffer protective film prepared in Example 1 has excellent anti-warping effect. It can also be seen from the above table that the anti-warping buffer protective film prepared in the present invention has good impact resistance and chemical corrosion resistance.

[0065] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing an anti-warping buffer protective film, characterized in that: The anti-warping buffer protective film comprises a protective layer, a substrate layer and a buffer layer from top to bottom, wherein the protective layer is formed by coating a protective film glue on an upper substrate layer and curing the protective layer, and the buffer layer is formed by coating a buffer layer glue on a lower substrate layer and curing the buffer layer, and the substrate layer is a PET base film; The preparation method comprises the following steps: S1. Weigh the raw materials by weight, and evenly mix 20-45 parts of acrylic resin, 4-6 parts of benzophenone, 100-250 parts of ethyl acetate, 0.05-0.5 parts of polydimethylsiloxane and 1-5 parts of anti-warping curing agent to prepare a protective film glue; S2, weighing the raw materials by weight, and evenly mixing 10-70 parts of elastic light-curable resin, 0.05-1 part of polyester-modified silicone and 1-5 parts of benzophenone to prepare a buffer layer glue; S3. Apply the protective film glue on the PET base film, cure it with UV light, apply the buffer layer glue on the other side of the PET base film, cure it with UV light, and perform laser bevel cutting to make an anti-warping buffer protective film with a thickness of 0.1-0.5mm.

2. The method for preparing an anti-warping buffer protective film according to claim 1, characterized in that: The anti-warping curing agent is prepared by the following method: Step A1: 4,4-diaminophenylsulfone and 200 mL of anhydrous ethanol were placed in a beaker, stirred at 60°C, then m-hydroxybenzaldehyde was dispersed in 100 mL of anhydrous ethanol, stirred at 60°C, and then slowly added dropwise to the beaker, the addition was completed within 2 hours, stirred at 60°C for 4 hours, cooled to room temperature, distilled under reduced pressure, dried in a vacuum oven at 60°C for 12 hours, then allyl chloride, potassium carbonate and 8 mL of anhydrous ethanol were added, stirred at 80°C, and reacted for 24 hours to obtain a compound; Step A2: triethylamine, N-aminopropylmorpholine and 10 mL of dichloromethane were placed in a reaction bottle, mixed, and stirred at room temperature for 20 min. Acryloyl chloride was dispersed in 10 mL of dichloromethane and then added to the reaction bottle. The temperature was controlled to be 0°C, and the reaction was continued for 0.5 h, and then the reaction was continued at room temperature for 8 h, and dried to obtain a morpholine compound. Step A3: Disperse the compound evenly in deionized water and ammonium persulfate, add the morpholine compound and stir evenly, heat to 70° C. under nitrogen protection and react for 4.5 hours, distill under reduced pressure, freeze and vacuum dry to obtain an anti-warping curing agent.

3. The method for preparing an anti-warping buffer protective film according to claim 2, characterized in that: In step A1, the usage ratio of 4,4-diaminophenylsulfone, m-hydroxybenzaldehyde, propylene chloride and potassium carbonate is 11.6-13.4 g: 6.1-7.2 g: 1-3 mol: 0.1-0.2 mol.

4. The method for preparing an anti-warping buffer protective film according to claim 2, characterized in that: The mass ratio of triethylamine, N-aminopropylmorpholine and acryloyl chloride in step A2 is 4.1-4.3 g: 0.42-0.53 g: 0.32-0.38 g.

5. The method for preparing an anti-warping buffer protective film according to claim 2, characterized in that: In step A3, the usage ratio of the compound, deionized water, ammonium persulfate, and morpholine compound is 3-5 g: 20 mL: 0.02 g: 5-8 g.

6. The method for preparing an anti-warping buffer protective film according to claim 1, characterized in that: The elastic light-curable resin is prepared by the following method: At room temperature, ethyl acetate, 2-phenoxyethyl acrylate and 1,6-hexanediamine are mixed and reacted for 2-5 hours, and then polyethylene glycol-200 diacrylate and trimethylolpropane triacrylate are added and mixed, and reacted for 2-4 hours to prepare an elastic light-curing resin.

7. Use of the anti-warping buffer protective film obtained by the preparation method according to claim 1 in protecting the screen of an electronic device.

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