PET (Polyethylene Terephthalate) protective film as well as preparation method and application thereof
By employing chemical bonding copolymerization and synergistic electrostatic conduction in PET protective film, the problems of antistatic agent precipitation and the influence of environmental temperature and humidity are solved, achieving long-lasting antistatic and anti-bubble properties, suitable for the surface of electronic products and optical devices.
Patent Information
- Application Number
- CN202610003525.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-05
- Publication Date
- 2026-02-17
AI Technical Summary
The antistatic agents added to existing pressure-sensitive adhesives will gradually leach out of the adhesive layer over time and transfer to the surface of the protected material, causing contamination. Furthermore, the antistatic effect is greatly affected by the ambient temperature and humidity.
By employing chemical bonding copolymerization and synergistic electrostatic conduction during the preparation of PET protective film, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt containing methacryloyloxy group is copolymerized with hard monomers to form a shell polymer molecular chain. Carboxylated GQDs are added to the core layer pre-emulsion to form nanoscale venting channels. Combined with dynamic crosslinking modification, the density of the adhesive layer and the interfacial wetting properties are improved, achieving long-lasting antistatic and anti-bubble effects.
It achieves long-lasting and stable antistatic properties, reduces the migration and precipitation of antistatic agents, reduces the impact of ambient temperature and humidity on antistatic effects, and improves anti-bubble ability and interfacial adhesion performance, making it suitable for a variety of substrates.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of electronic product protective film technology, specifically to a PET protective film, its preparation method, and its application. Background Technology
[0002] Protective films are generally made of polyolefin plastic film as the base material, with rubber or acrylic ester as the pressure-sensitive adhesive, and are processed into a film-like material through special methods. The protective film is attached to the surface of the material and participates in the processing of the protected material, such as cutting, folding, drilling, and stamping. It is used for short-term surface protection during the production, transportation, assembly, or processing of products, preventing contamination and damage to the material surface. Protective films are mainly used for dust prevention and protection in the manufacturing process of electronic products, requiring specific characteristics such as reliable low adhesion, excellent weather resistance, repeated adhesion, excellent wetting and venting properties, high optical transmittance, excellent water repellency, and superior surface abrasion and scratch resistance. Because the protective film itself is composed of plastic film and pressure-sensitive adhesive material, both of which are non-conductive polymer materials... Pressure-sensitive adhesives have high surface resistance. During packaging and transportation, the static electricity generated by friction is limited by the low polarity and low water absorption of the pressure-sensitive adhesive itself, and is not easy to eliminate. It is easy to further accumulate static electricity, thereby affecting the product's performance indicators and surface cleanliness, and may even cause hazards such as electric shock, short circuit, and electrostatic discharge. Therefore, it is necessary to modify the protective film to be antistatic.
[0003] Traditional antistatic protective films generally use two types of antistatic agents: one is an externally coated antistatic agent, which belongs to a structural conductive polymer; the other is an internally added antistatic agent, which belongs to an ionic liquid additive. The former, due to the presence of conjugated double bonds in its molecular chain structure, allows π electrons to move freely within the molecular chain, resulting in a high carrier mobility. It can be directly coated onto the film surface to form an antistatic coating. The latter, used in combination with pressure-sensitive adhesives, forms a conductive layer on the surface of the pressure-sensitive adhesive layer after coating and drying, accelerating the rapid dissipation of surface static charge and giving the protective film a certain antistatic effect. Currently, the antistatic functionalization modification of pressure-sensitive adhesives for protective films, both domestically and internationally, mainly involves solvent-based acrylic ester systems, i.e., adding internally added antistatic agents to acrylic pressure-sensitive adhesives. Studies have shown that adding antistatic agents can significantly improve the antistatic properties of acrylic pressure-sensitive adhesives, reduce the tear voltage of the protective film, and have virtually no impact on the mechanical properties of the protective film. However, this method has many hidden dangers. For example, over time, the antistatic agent will gradually precipitate from the adhesive layer and transfer to the surface of the protected material, causing pollution. In addition, the antistatic effect is greatly affected by the ambient temperature and humidity. Summary of the Invention
[0004] The purpose of this invention is to provide a PET protective film, its preparation method, and its application, thereby solving the following technical problems: The antistatic agents added to existing pressure-sensitive adhesives will gradually leach out of the adhesive layer over time and transfer to the surface of the protected material, causing contamination. Furthermore, the antistatic effect is greatly affected by the ambient temperature and humidity.
[0005] The objective of this invention can be achieved through the following technical solutions: A method for preparing a PET protective film includes the following steps: coating a pressure-sensitive adhesive onto the surface of a plastic film layer and curing it to form an adhesive layer, thereby obtaining a PET protective film; The preparation method of pressure-sensitive adhesive includes the following steps: S1: Butyl acrylate, isooctyl acrylate, ethyl acrylate, polyethylene glycol monoacrylate, carboxylated GQDs, deionized water, and ammonium persulfate are added to reactor A and dispersed to obtain a core layer pre-emulsion. In a nitrogen atmosphere, methyl methacrylate, acrylonitrile, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, azobisisobutyronitrile, and a mixed solvent were added to reactor B and dispersed to obtain a shell pre-emulsion. S2: Add the mixed solvent to reactor C, heat to 75-80℃, add the core layer pre-emulsion dropwise under constant temperature stirring, and keep warm for 1-2 hours; heat to 85-90℃, add the shell layer pre-emulsion dropwise under stirring, and keep warm for 1-3 hours; cool to 50-60℃, add hydroxyethyl acrylate, N-hydroxymethylacrylamide, dynamic disulfide crosslinking agent, and azobisisobutyronitrile, and keep warm for 1-1.5 hours; add additives for dispersion, cool, and filter to obtain pressure-sensitive adhesive; The preparation method of antistatic monomers includes the following steps: In a nitrogen atmosphere, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, anhydrous potassium carbonate, and N,N-dimethylformamide were added to a reaction vessel. The temperature was controlled at 70-75℃, and the mixture was stirred for 0.5-1 h. Then, 3-chloro-2-hydroxypropyl methacrylate was added, and the reaction was maintained at this temperature for 6-9 h. After cooling, filtration, washing, and rotary evaporation, the antistatic monomer was obtained.
[0006] As a further embodiment of the present invention: the addition ratio of butyl acrylate, isooctyl acrylate, ethyl acrylate, polyethylene glycol monoacrylate, carboxylated GQDs, deionized water, and ammonium persulfate in S1 is 50-60g: 20-25g: 5-8g: 3-5g: 0.3-0.5g: 30-40mL: 0.15-0.25g.
[0007] As a further aspect of the present invention: the mixed solvent in S1 is composed of ethyl acetate and toluene in a mass ratio of 3:1; The mass ratio of methyl methacrylate, acrylonitrile, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, azobisisobutyronitrile, and mixed solvent is 8-12:2-3:1-2:0.2-0.3:30-40.
[0008] As a further aspect of the present invention: the mixed solvent in S2 is composed of ethyl acetate and toluene in a mass ratio of 3:1; the dynamic disulfide bond crosslinking agent is bis(2-methacryloyloxyethyl) disulfide; The mass ratio of the mixed solvent, core preemulsion, shell preemulsion, hydroxyethyl acrylate, N-hydroxymethylacrylamide, dynamic disulfide crosslinking agent, azobisisobutyronitrile, and additives is 70-80:110-130:44-57:1-2:0.2-0.4:0.3-0.6:0.05-0.1:0.8-1.5.
[0009] As a further aspect of the present invention: in the preparation method of the antistatic monomer, the addition ratio of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, anhydrous potassium carbonate, N,N-dimethylformamide, and 3-chloro-2-hydroxypropyl methacrylate is 100g: 30-35g: 200-400mL: 120-140g.
[0010] As a further aspect of the present invention: the additive is composed of KH550, defoamer, and antioxidant in a mass ratio of 0.5-1:0.1-0.2:0.2-0.3.
[0011] As a further aspect of the present invention: the plastic film layer is a PET film; the thickness of the PET film is 15-25μm; and the thickness of the adhesive layer is 10-30μm.
[0012] As a further aspect of the present invention: before coating the plastic film layer with pressure-sensitive adhesive, the surface of the plastic film layer is subjected to corona treatment, and pressure-sensitive adhesive is coated on the corona-treated PET substrate surface. The corona treatment power is 0.6-1.4kW, the frequency is 10-20kHz, and the linear velocity of the film during treatment is 3-6m / min. Optical-grade transparent PET film ensures a light transmittance exceeding 92% while maintaining mechanical strength.
[0013] A PET protective film, made by any of the above preparation methods.
[0014] The aforementioned PET protective film is used on the surface of electronic products and optical devices.
[0015] The beneficial effects of this invention are: (1) Long-lasting antistatic properties This application achieves long-lasting antistatic effects through chemically bonded copolymerization and synergistic electrostatic conduction. First, the antistatic agent is a 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt containing methacryloxy group. This salt undergoes free radical copolymerization with hard monomers (MMA, AN), chemically bonding the ionic liquid segments to the shell polymer molecular chain, effectively preventing the migration and precipitation of the antistatic components. Second, the hydrophilic segments of polyethylene glycol monoacrylate form a hygroscopic and hydroelectric film on the adhesive surface, while MA-EMIM-TFSI provides a stable ionic conductivity channel. Under the synergistic effect of both, static charge can be rapidly dissipated, achieving a long-lasting and stable antistatic effect, and the antistatic performance is significantly reduced by the influence of ambient temperature and humidity.
[0016] (2) Anti-bubbling performance This application first adds carboxylated GQDs to the core layer pre-emulsion to form nanoscale venting channels, which can quickly expel gases generated during bonding and aging, significantly improving anti-bubble capability. Secondly, through core-shell structure and dynamic cross-linking modification, the density of the adhesive layer is improved while avoiding excessive rigidity, reducing small molecule residues within the adhesive layer and preventing the volatilization of small molecules at high temperatures to form bubbles. Finally, this application introduces an organosilane coupling agent (KH-550) to improve the interfacial wetting properties between the adhesive layer and substrates such as glass, PMMA, and PC, accelerating the expulsion of interfacial gases during bonding and preventing gas retention. The pressure-sensitive adhesive prepared in this application reduces the swelling rate of the adhesive layer through monomer ratio adjustment, reducing moisture penetration to the bonding interface under high temperature and humidity conditions, effectively preventing moisture vaporization and bubble formation.
[0017] The PET protective film prepared in this application has multiple properties such as antistatic, anti-bubble, low residue, and high light transmittance. It can be widely adapted to various substrates such as glass, PMMA, and PC, and has diversified application scenarios. Detailed Implementation
[0018] 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.
[0019] Example 1: The preparation method of the antistatic monomer includes the following steps: In a nitrogen atmosphere, 100g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 30g of anhydrous potassium carbonate, and 200mL of N,N-dimethylformamide were added to a reaction vessel. The temperature was controlled at 70℃, and the mixture was stirred for 0.5h. Then, 120g of 3-chloro-2-hydroxypropyl methacrylate was added, and the reaction was maintained at this temperature for 6h. After cooling, filtration, washing, and rotary evaporation, the antistatic monomer was obtained.
[0020] The preparation method of pressure-sensitive adhesive includes the following steps: S1: Add 50g butyl acrylate, 20g isooctyl acrylate, 5g ethyl acrylate, 3g polyethylene glycol monoacrylate, 0.3g carboxylated GQDs (purchased from Xianfeng Nanotechnology), 30mL deionized water, and 0.15g ammonium persulfate to reactor A, disperse at 1000r / min for 30min to obtain the core layer pre-emulsion; S2: In a nitrogen atmosphere, 8g of methyl methacrylate, 2g of acrylonitrile, 1g of antistatic monomer, 0.2g of azobisisobutyronitrile, 7.5g of toluene and 22.5g of ethyl acetate were added to reactor B and dispersed at 800r / min for 25min to obtain a shell pre-emulsion. S3: Add 17.5g toluene and 52.5g ethyl acetate to reactor C, heat to 75℃, and add the core pre-emulsion prepared in S1 at a controlled dropping rate under constant temperature stirring. The addition is completed in 2 hours, and the mixture is kept at this temperature for 1.5 hours. Heat to 85℃, and add the shell pre-emulsion prepared in S2 at a controlled dropping rate under constant temperature stirring. The addition is completed in 2 hours, and the mixture is kept at this temperature for 2 hours. Cool down to 55℃, add 1g hydroxyethyl acrylate, 0.2g N-hydroxymethylacrylamide, 0.3g bis(2-methacryloyloxyethyl) disulfide, and 0.05g azobisisobutyronitrile, and keep at this temperature for 1-1.5 hours. Then add 0.5g KH550, 0.1g polyether-modified silicone defoamer, and 0.2g antioxidant 1010 for dispersion, cool down, and filter through a 200-mesh filter to obtain the pressure-sensitive adhesive.
[0021] Example 2: The preparation method of the antistatic monomer includes the following steps: In a nitrogen atmosphere, 100g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 32g of anhydrous potassium carbonate, and 300mL of N,N-dimethylformamide were added to a reaction vessel. The temperature was controlled at 75℃, and the mixture was stirred for 0.5h. Then, 130g of 3-chloro-2-hydroxypropyl methacrylate was added, and the reaction was maintained at this temperature for 7h. After cooling, filtration, washing, and rotary evaporation, the antistatic monomer was obtained.
[0022] The preparation method of pressure-sensitive adhesive includes the following steps: S1: Add 55g butyl acrylate, 22g isooctyl acrylate, 7g ethyl acrylate, 4g polyethylene glycol monoacrylate, 0.4g carboxylated GQDs (purchased from Xianfeng Nanotechnology), 35mL deionized water, and 0.2g ammonium persulfate to reactor A, disperse at 1000r / min for 30min to obtain the core layer pre-emulsion; S2: In a nitrogen atmosphere, 10g of methyl methacrylate, 2.5g of acrylonitrile, 1.5g of antistatic monomer, 0.3g of azobisisobutyronitrile, 8.7g of toluene and 26.1g of ethyl acetate were added to reactor B and dispersed at 800r / min for 25min to obtain a shell pre-emulsion. S3: Add 18.7g toluene and 56g ethyl acetate to reactor C, heat to 80℃, and add the core layer pre-emulsion at a controlled dropping rate under constant temperature stirring. The addition is completed in 2 hours, and the mixture is kept at this temperature for 1.5 hours. Heat to 90℃, and add the shell layer pre-emulsion at a controlled dropping rate under constant temperature stirring. The addition is completed in 2 hours, and the mixture is kept at this temperature for 2 hours. Cool to 55℃, add 1.5g hydroxyethyl acrylate, 0.3g N-hydroxymethylacrylamide, 0.5g bis(2-methacryloyloxyethyl) disulfide, and 0.08g azobisisobutyronitrile, and keep at this temperature for 1 hour. Then add 0.8g KH550, 0.1g polyether-modified silicone defoamer, and 0.2g antioxidant 1010 for dispersion, cool, and filter through a 200-mesh filter to obtain the pressure-sensitive adhesive.
[0023] Example 3: The preparation method of the antistatic monomer includes the following steps: In a nitrogen atmosphere, 100g of antistatic monomer, 35g of anhydrous potassium carbonate, and 400mL of N,N-dimethylformamide were added to a reaction vessel. The temperature was controlled at 75℃, and the mixture was stirred for 1 hour. Then, 140g of 3-chloro-2-hydroxypropyl methacrylate was added, and the reaction was maintained at the same temperature for 9 hours. After cooling, filtration, washing, and rotary evaporation, the antistatic monomer was obtained.
[0024] The preparation method of pressure-sensitive adhesive includes the following steps: S1: Add 60g butyl acrylate, 25g isooctyl acrylate, 8g ethyl acrylate, 5g polyethylene glycol monoacrylate, 0.5g carboxylated GQDs (purchased from Xianfeng Nanotechnology), 40mL deionized water, and 0.25g ammonium persulfate to reactor A, disperse at 1000r / min for 30min to obtain the core layer pre-emulsion; S2: In a nitrogen atmosphere, 12g of methyl methacrylate, 3g of acrylonitrile, 2g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.3g of azobisisobutyronitrile, 30g of ethyl acetate and 10g of toluene were added to reactor B and dispersed at 800r / min for 25min to obtain a shell pre-emulsion. S3: Add 60g ethyl acetate and 20g toluene to reactor C, heat to 80℃, and add the core layer pre-emulsion at a controlled dropping rate under constant temperature stirring. The addition is completed in 2 hours, and the mixture is kept at this temperature for 1.5 hours. Heat to 90℃, and add the shell layer pre-emulsion at a controlled dropping rate under constant temperature stirring. The addition is completed in 2 hours, and the mixture is kept at this temperature for 2 hours. Cool down to 55℃, add 2g hydroxyethyl acrylate, 0.4g N-hydroxymethylacrylamide, 0.6g bis(2-methacryloyloxyethyl) disulfide, and 0.1g azobisisobutyronitrile, and keep at this temperature for 1.5 hours. Then add 1g KH550, 0.2g polyether-modified silicone defoamer, and 0.3g antioxidant 1010 for dispersion, cool down, and filter through a 200-mesh filter to obtain the pressure-sensitive adhesive.
[0025] Example 4: A method for preparing a PET protective film, comprising the following steps: A1: Corona treatment of the surface of an optical-grade transparent PET film with a thickness of 25 μm (power 1.2 kW, frequency 18 kHz, film moving linear speed of 5 m / min) to obtain a pretreated film; A2: Coat the surface of the plastic film layer with the pressure-sensitive adhesive prepared in Example 1, cure it, and form a PET protective film with an adhesive layer thickness of 25 μm.
[0026] Example 5: Compared with Example 4, only the pressure-sensitive adhesive prepared in Example 1 was replaced with the pressure-sensitive adhesive prepared in Example 2, resulting in a PET protective film with an adhesive layer thickness of 25 μm.
[0027] Example 6: Compared with Example 4, only the pressure-sensitive adhesive prepared in Example 1 was replaced with the pressure-sensitive adhesive prepared in Example 3, resulting in a PET protective film with an adhesive layer thickness of 25 μm.
[0028] Comparative Example 1: The preparation method of the pressure-sensitive adhesive includes the following steps: S1: Add 55g butyl acrylate, 22g isooctyl acrylate, 7g ethyl acrylate, 4g polyethylene glycol monoacrylate, 0.4g carboxylated GQDs (purchased from Xianfeng Nanotechnology), 35mL deionized water, and 0.2g ammonium persulfate to reactor A, disperse at 1000r / min for 30min to obtain the core layer pre-emulsion; S2: In a nitrogen atmosphere, 10g of methyl methacrylate, 2.5g of acrylonitrile, 1.5g of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, 0.3g of azobisisobutyronitrile, 8.7g of toluene, and 26.1g of ethyl acetate were added to reactor B and dispersed at 800r / min for 25min to obtain a shell pre-emulsion. S3: Add 18.7g toluene and 56g ethyl acetate to reactor C, heat to 80℃, and add the core layer pre-emulsion at a controlled dropping rate under constant temperature stirring. The addition is completed in 2 hours, and the mixture is kept at this temperature for 1.5 hours. Heat to 90℃, and add the shell layer pre-emulsion at a controlled dropping rate under constant temperature stirring. The addition is completed in 2 hours, and the mixture is kept at this temperature for 2 hours. Cool to 55℃, add 1.5g hydroxyethyl acrylate, 0.3g N-hydroxymethylacrylamide, 0.5g bis(2-methacryloyloxyethyl) disulfide, and 0.08g azobisisobutyronitrile, and keep at this temperature for 1 hour. Then add 0.8g KH550, 0.1g polyether-modified silicone defoamer, and 0.2g antioxidant 1010 for dispersion, cool, and filter through a 200-mesh filter to obtain the pressure-sensitive adhesive.
[0029] Comparative Example 2: The preparation method of the pressure-sensitive adhesive includes the following steps: S1: Add 55g butyl acrylate, 22g isooctyl acrylate, 7g ethyl acrylate, 4g polyethylene glycol monoacrylate, 35mL deionized water, and 0.2g ammonium persulfate to reactor A, and disperse at 1000r / min for 30min to obtain the core layer pre-emulsion. S2: In a nitrogen atmosphere, 10g of methyl methacrylate, 2.5g of acrylonitrile, 1.5g of the antistatic agent prepared in Example 2, 0.3g of azobisisobutyronitrile, 8.7g of toluene, and 26.1g of ethyl acetate were added to reactor B and dispersed at 800r / min for 25min to obtain a shell pre-emulsion. S3: Add 18.7g toluene and 56g ethyl acetate to reactor C, heat to 80℃, and add the core layer pre-emulsion at a controlled dropping rate under constant temperature stirring. The addition is completed in 2 hours, and the mixture is kept at this temperature for 1.5 hours. Heat to 90℃, and add the shell layer pre-emulsion at a controlled dropping rate under constant temperature stirring. The addition is completed in 2 hours, and the mixture is kept at this temperature for 2 hours. Cool to 55℃, add 1.5g hydroxyethyl acrylate, 0.3g N-hydroxymethylacrylamide, 0.5g bis(2-methacryloyloxyethyl) disulfide, and 0.08g azobisisobutyronitrile, and keep at this temperature for 1 hour. Then add 0.8g KH550, 0.1g polyether-modified silicone defoamer, and 0.2g antioxidant 1010 for dispersion, cool, and filter through a 200-mesh filter to obtain the pressure-sensitive adhesive.
[0030] Comparative Example 3: The preparation method of the pressure-sensitive adhesive includes the following steps: S1: Add 55g butyl acrylate, 22g isooctyl acrylate, 7g ethyl acrylate, 4g polyethylene glycol monoacrylate, 0.4g carboxylated GQDs (purchased from Xianfeng Nanotechnology), 35mL deionized water, and 0.2g ammonium persulfate to reactor A, disperse at 1000r / min for 30min to obtain the core layer pre-emulsion; S2: In a nitrogen atmosphere, 10g of methyl methacrylate, 2.5g of acrylonitrile, 1.5g of the antistatic agent prepared in Example 2, 0.3g of azobisisobutyronitrile, 8.7g of toluene, and 26.1g of ethyl acetate were added to reactor B and dispersed at 800r / min for 25min to obtain a shell pre-emulsion. S3: Add 18.7g toluene and 56g ethyl acetate to reactor C, heat to 80℃, and add the core layer pre-emulsion at a controlled dropping rate under constant temperature stirring. The addition is completed in 2 hours, and the mixture is kept at this temperature for 1.5 hours. Then, heat to 90℃, add the shell layer pre-emulsion at a controlled dropping rate under constant temperature stirring. The addition is completed in 2 hours, and the mixture is kept at this temperature for 2 hours. Then, cool to 55℃, add 1.5g hydroxyethyl acrylate, 0.3g N-hydroxymethylacrylamide, and 0.08g azobisisobutyronitrile, and keep at this temperature for 1 hour. Then, add 0.8g KH550, 0.1g polyether-modified silicone defoamer, and 0.2g antioxidant 1010 for dispersion, cool, and filter through a 200-mesh filter to obtain the pressure-sensitive adhesive.
[0031] Comparative Example 4: Compared with Example 4, only the pressure-sensitive adhesive prepared in Example 1 was replaced with the pressure-sensitive adhesive prepared in Comparative Example 1, resulting in a PET protective film with an adhesive layer thickness of 25 μm.
[0032] Comparative Example 5: Compared with Example 4, only the pressure-sensitive adhesive prepared in Example 1 used in Example 4 was replaced with the pressure-sensitive adhesive prepared in Comparative Example 2, resulting in a PET protective film with an adhesive layer thickness of 25 μm.
[0033] Comparative Example 6: Compared with Example 4, only the pressure-sensitive adhesive prepared in Example 1 used in Example 4 was replaced with the pressure-sensitive adhesive prepared in Comparative Example 3, resulting in a PET protective film with an adhesive layer thickness of 25 μm.
[0034] Performance testing (1) Initial tack: The test was conducted according to GB / T 4852-2002 "Test method for initial tack of pressure sensitive adhesive tape (rolling ball method)", and the test results are shown in Table 1; (2) Holding power: The test was conducted according to GB / T 4851-2014 "Test method for holding power of adhesive tapes". The test results are shown in Table 1. Table 1: Statistical Table of Adhesion Performance Test Data
[0035] As shown in Table 1, the pressure-sensitive adhesive prepared in this application, when applied to the surface of a PET protective film, imparts excellent initial tack and holding power to the material.
[0036] (3) 180° peel strength: The 180° peel strength was tested according to GB / T 2792-2014 "Test method for peel strength of adhesive tape". The test results are shown in Table 2. (4) Heat resistance test: According to the 180° peel strength test method, the product is placed on a mirror stainless steel plate and baked in an oven at 120° for 24 hours. After cooling, the peel strength is tested and the peel strength retention rate is calculated. The residual glue on the steel plate is observed. If the residual glue area is less than 10%, it is considered a small amount of glue loss. If the residual glue area is greater than 10%, it is considered a serious glue loss. The test results are shown in Table 2. Table 2: Statistical Table of Peel Strength Performance Test Data
[0037] As shown in Table 2, the pressure-sensitive adhesive prepared in this application, when applied to PET protective film, imparts good peel strength to the protective film and has good high-temperature resistance. The peel strength retention rate is higher than 85% in high-temperature environments, and there is no adhesive residue after peeling, which will not contaminate the material surface.
[0038] (5) Transmittance and haze test: Transmittance and haze were tested according to ASTM D1003. The test results are shown in Table 3. Table 3: Statistical Table of Transmittance and Haze Performance Test Data
[0039] As shown in Table 3, the protective film prepared in this application has a transmittance of over 95% and a haze of less than 0.5% in the visible light wavelength range, ensuring its high transmittance and clarity in application.
[0040] (6) Anti-bubble performance: 3D high temperature and high humidity test, 40℃ / 90%RH, 72h; high temperature aging test: 80℃, 72h; observe the bonding structure after the test, and the test results are shown in Table 4; Table 4: Statistical Table of Anti-bubbling Performance Test Data
[0041] As shown in Table 4, the protective film prepared in this application has anti-bubble properties. When the protective film prepared in this application is applied to the surface of materials such as glass, PMMA, and PC, no bubbles are found in the adhesive structure after 3 days of high temperature and high humidity or high temperature aging test.
[0042] (7) Surface resistance: According to the parallel electrode sensing method of ASTM D-257 standard, the surface resistance was automatically tested using a high-precision OP-AMP integrated amplifier and measured after 30 days. The test results are shown in Table 5. Peel-off voltage: In an indoor environment (24±4℃, 50-75%RH), the high-energy protective film was applied to the surface of the mobile phone assembly screen and left to stand for 24 hours. The protective film was then peeled off at a rate of 0.5m / s. The peak static voltage on the screen was tested when the protective film was peeled off from the screen. The peel-off voltage was also tested after 30 days. The test results are shown in Table 5. (8) Antistatic agent precipitation test: The protective film was attached to the PMMA surface and placed at 80°C for 72 hours. After removing the film, the PMMA surface was tested for antistatic agent residue (infrared spectroscopy analysis; test results are shown in Table 5). Table 5: Statistical Table of Antistatic Performance Test Data
[0043] As shown in Table 5, the pressure-sensitive adhesive prepared in this application has long-lasting antistatic properties.
[0044] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.
Claims
1. A method for preparing a PET protective film, characterized in that, The process includes the following steps: applying pressure-sensitive adhesive to the surface of a plastic film layer and curing it to form an adhesive layer, thereby obtaining a PET protective film; The preparation method of the pressure-sensitive adhesive includes the following steps: S1: Butyl acrylate, isooctyl acrylate, ethyl acrylate, polyethylene glycol monoacrylate, carboxylated GQDs, deionized water, and ammonium persulfate are added to reactor A and dispersed to obtain a core layer pre-emulsion. In a nitrogen atmosphere, methyl methacrylate, acrylonitrile, antistatic monomer, azobisisobutyronitrile, and mixed solvent were added to reactor B and dispersed to obtain a shell pre-emulsion. S2: Add the mixed solvent to reactor C, heat to 75-80℃, add the core layer pre-emulsion dropwise under constant temperature stirring, and keep warm for 1-2 hours; heat to 85-90℃, add the shell layer pre-emulsion dropwise under stirring, and keep warm for 1-3 hours; cool to 50-60℃, add hydroxyethyl acrylate, N-hydroxymethylacrylamide, dynamic disulfide crosslinking agent, and azobisisobutyronitrile, and keep warm for 1-1.5 hours; add additives for dispersion, cool, and filter to obtain pressure-sensitive adhesive; The preparation method of the antistatic monomer includes the following steps: In a nitrogen atmosphere, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, anhydrous potassium carbonate, and N,N-dimethylformamide were added to a reaction vessel. The temperature was controlled at 70-75℃, and the mixture was stirred for 0.5-1 h. Then, 3-chloro-2-hydroxypropyl methacrylate was added, and the reaction was maintained at this temperature for 6-9 h. After cooling, filtration, washing, and rotary evaporation, the antistatic monomer was obtained.
2. The method for preparing a PET protective film according to claim 1, characterized in that, The addition ratio of butyl acrylate, isooctyl acrylate, ethyl acrylate, polyethylene glycol monoacrylate, carboxylated GQDs, deionized water, and ammonium persulfate in S1 is 50-60g: 20-25g: 5-8g: 3-5g: 0.3-0.5g: 30-40mL: 0.15-0.25g.
3. The method for preparing a PET protective film according to claim 1, characterized in that, The mixed solvent in S1 is composed of ethyl acetate and toluene in a mass ratio of 3:1; The mass ratio of methyl methacrylate, acrylonitrile, antistatic monomer, azobisisobutyronitrile, and mixed solvent is 8-12:2-3:1-2:0.2-0.3:30-40.
4. The method for preparing a PET protective film according to claim 1, characterized in that, The mixed solvent in S2 is composed of ethyl acetate and toluene in a mass ratio of 3:1; the dynamic disulfide crosslinking agent is bis(2-methacryloyloxyethyl) disulfide; The mass ratio of the mixed solvent, core preemulsion, shell preemulsion, hydroxyethyl acrylate, N-hydroxymethylacrylamide, dynamic disulfide crosslinking agent, azobisisobutyronitrile, and additives is 70-80:110-130:44-57:1-2:0.2-0.4:0.3-0.6:0.05-0.1:0.8-1.
5.
5. The method for preparing a PET protective film according to claim 1, characterized in that, In the preparation method of the antistatic monomer, the addition ratio of 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide salt, anhydrous potassium carbonate, N,N-dimethylformamide, and 3-chloro-2-hydroxypropyl methacrylate is 100g: 30-35g: 200-400mL: 120-140g.
6. The method for preparing a PET protective film according to claim 1, characterized in that, The additives consist of KH550, defoamer, and antioxidant in a mass ratio of 0.5-1:0.1-0.2:0.2-0.
3.
7. The method for preparing a PET protective film according to claim 1, characterized in that, The plastic film layer is a PET film; the PET film thickness is 15-25μm; the adhesive layer thickness is 10-30μm.
8. The method for preparing a PET protective film according to claim 1, characterized in that, Before the pressure-sensitive adhesive is applied to the plastic film layer, the surface of the plastic film layer is subjected to corona treatment, and then the pressure-sensitive adhesive is applied to the corona-treated PET substrate surface. The power of the corona treatment is 0.6-1.4kW, the frequency is 10-20kHz, and the linear velocity of the membrane during treatment is 3-6m / min.
9. A PET protective film, characterized in that, It is prepared by any one of the preparation methods described in claims 1-8.
10. The PET protective film as described in claim 9 is applied to the surface of electronic products and optical devices.