A high-hardness and high-wear-resistant protective film and its preparation method

Abstract

The present application relates to the field of protective films, and more specifically, to a high-hardness, high-wear-resistant protective film and its preparation method. The high-hardness, high-wear-resistant protective film is sequentially provided with a first protective layer, a hardening layer, a PET layer, a secondary curing layer, an adhesive layer, and a second protective layer from the upper surface to the lower surface. The hardening layer is formed by applying a hardening liquid to the surface of the PET layer with a coating thickness of 3-5 μm and curing. The hardening liquid is composed of the following raw materials in parts by weight: acrylate polymer, photoinitiator, thermal initiator, auxiliary agent, solvent, and inorganic nanoparticles. The acrylate polymer is composed of a variety of difunctional polyurethane acrylate, hexafunctional polyurethane acrylate, and pentafunctional polyurethane acrylate. By formulating the hardening layer and controlling the coating thickness within the range of 3-5 μm, the protective film not only has ultra-high hardness (≥9H) and wear resistance, but also reduces the possibility of warping.

Description

Technical Field

[0001] The present application relates to the field of protective films, and more specifically, to a high-hardness and high-wear-resistant protective film and a preparation method thereof. Background Art

[0002] 3C display screen protectors are widely used in modern society due to their portability and touch functionality. With the increasing popularity of smartphones and tablets, demand for screen protectors, a key component for protecting display screens, has been increasing year by year. The hardness and wear resistance of screen protectors directly impact their lifespan and user experience, making high-hardness and wear-resistant screen protectors a pressing need in the current market.

[0003] Currently, most common screen protectors on the market use a PET substrate with a certain thickness of hard coating applied to its surface to enhance its hardness and wear resistance. To improve the hardness and wear resistance of screen protectors, two common solutions are used: one is to harden the substrate surface through a coating treatment to impart a certain degree of hardness to the film; the other is to use special materials with higher hardness as the substrate or coating to enhance the film's hardness. However, these measures often require increasing the coating thickness to over 20μm to achieve the required hardness and wear resistance.

[0004] While increasing coating thickness can improve the hardness and wear resistance of screen protectors to a certain extent, it also presents a series of problems. In particular, increased coating thickness can cause significant warping of the screen protector, limiting its application in high-end products. Furthermore, excessively thick hardened coatings can increase material costs and processing difficulties, further impacting the market competitiveness of the finished product. These issues limit the current development potential of screen protectors that meet the requirements of high hardness and wear resistance. Summary of the Invention

[0005] In order to obtain higher wear resistance and hardness and reduce the phenomenon of warping, the present application provides a high-hardness and high-wear-resistant protective film and a preparation method thereof.

[0006] In a first aspect, the present application provides a high-hardness and high-wear-resistant protective film, which is provided with a first protective layer, a hardening layer, a PET layer, a secondary curing layer, an adhesive layer, and a second protective layer in sequence from the upper surface to the lower surface; the hardening layer is formed by applying a hardening liquid to the surface of the PET layer with a coating thickness of 3-5 μm and curing; the hardening liquid is composed of the following raw materials in parts by weight:

[0007] 30-50 parts of acrylic polymer

[0008] 0.5-2 parts of photoinitiator

[0009] Thermal initiator 0.05-0.2 parts

[0010] 0.2-0.8 parts of additives

[0011] 30-50 parts solvent

[0012] 3-10 parts of inorganic nanoparticles;

[0013] The acrylate polymer is composed of multiple types of difunctional polyurethane acrylate, hexafunctional polyurethane acrylate, and pentafunctional polyurethane acrylate.

[0014] By employing this technical solution, the protective film's hardened layer is formed by applying a hardening liquid to the surface of the PET layer and curing it. The coating thickness is controlled to 3-5μm, resulting in a protective film with high hardness while maintaining excellent flexibility and low warpage. The acrylic polymer in the hardening liquid is a combination of difunctional, hexafunctional, and pentafunctional urethane acrylates. Crosslinking and copolymerization reactions occur under the action of photoinitiators and thermal initiators, resulting in a hardened layer with excellent hardness and wear resistance.

[0015] Furthermore, the inorganic nanoparticles are inorganic fillers that have reinforcing and wear-resistant effects, and synergistically work with acrylic polymers to further improve wear resistance and hardness, so that the protective film can effectively resist scratches during long-term use while maintaining anti-fingerprint effects.

[0016] In summary, the present application selects a plurality of difunctional polyurethane acrylates, hexafunctional polyurethane acrylates, and pentafunctional polyurethane acrylates for compounding, and then combines them with inorganic nano-ions, so that the obtained hardening liquid, after coating and curing at 3-5μm, the obtained hardened layer has excellent wear resistance and high hardness, thereby improving the overall wear resistance, hardness and flatness of the screen protective film, and reducing the application limitations caused by warping of high-hardness protective films.

[0017] Preferably, the auxiliary agent is one or more of a wetting agent, an antioxidant, a dispersant, and an anti-settling agent.

[0018] By adopting the above technical solution, the dispersion and wetting properties of the hardening liquid raw material system are improved, further promoting processing convenience and making the hardened layer have better hardness and wear resistance, thereby significantly improving the overall performance of the screen protector.

[0019] Preferably, the acrylate polymer is composed of difunctional polyurethane acrylate, hexafunctional polyurethane acrylate, and pentafunctional polyurethane acrylate in a weight ratio of 1:(1-5):(0.3-1.5).

[0020] By adopting the above technical solution, the hardened layer has superior hardness and wear resistance. Specifically, the acrylate polymer is composed of difunctional polyurethane acrylate, hexafunctional polyurethane acrylate, and pentafunctional polyurethane acrylate in a weight ratio of 1:(1-5):(0.3-1.5), which acts synergistically to further improve the hardened layer's comprehensive performance in terms of high hardness and high wear resistance. This significantly enhances the overall wear resistance and hardness of the protective film, reduces warping, and improves its practicality.

[0021] Preferably, the photoinitiator is an acetophenone photoinitiator.

[0022] By adopting the above technical solution, the preferred acetophenone photoinitiator can effectively improve the curing efficiency and curing effect of the hardened layer, so that the hardened layer has higher hardness and wear resistance during the formation process, thereby making the entire protective film have better comprehensive performance.

[0023] Preferably, the thermal initiator is a peroxide thermal initiator and / or an azo thermal initiator.

[0024] By adopting this technical solution, the high-hardness, high-wear-resistant protective film maintains ultra-high hardness and high wear resistance while effectively controlling the coating thickness within the 3-5μm range, avoiding warping problems caused by coating thickening. The use of peroxide and / or azo thermal initiators as thermal initiators further optimizes the curing effect of the hardened layer, ensuring rapid curing at lower temperatures and improving overall production efficiency, resulting in a final product that combines the advantages of high hardness, high wear resistance, and low warping.

[0025] Preferably, the solvent is composed of one or more of PM, MIBK, BA, and EA.

[0026] By adopting this technical solution, the solvent in the hardening liquid can evaporate quickly, ensuring the uniformity and stability of the coating, thereby improving the film quality and overall performance of the hardened layer. Specifically, using one or more of PM, MIBK, BA, and EA as solvents not only facilitates the good dissolution and dispersion of the hardening liquid, but also effectively controls the drying speed of the coating, avoiding coating defects or performance degradation caused by improper solvent selection, thereby ensuring the hardened layer has excellent hardness and wear resistance.

[0027] Among them, PM is propylene glycol methyl ether, MIBK is methyl isobutyl ketone, BA is butyl butyrate, and EA is ethyl acetate.

[0028] Preferably, the inorganic nanoparticles are composed of one or more of nano-SiO2, nano-Al2O3, and aluminosilicate crystals.

[0029] By adopting the above technical solution, the hardened layer has better hardness and wear resistance. At the same time, the inorganic nanoparticles composed of one or more of nano-SiO2, nano-Al2O3, and aluminosilicate crystals are combined to further significantly improve the wear resistance and effectively deal with the wear problem during long-term use.

[0030] Aluminosilicate crystals are primarily composed of silicon-oxygen (Si-O) and aluminum-oxygen (Al-O) bonds, with their basic structural units being silicon-oxygen tetrahedrons and aluminum-oxygen hexahedrons. A silicon-oxygen tetrahedron is composed of one silicon atom and four oxygen atoms, while an aluminum-oxygen hexahedron is composed of one aluminum atom and six oxygen atoms. These basic structural units are linked together by shared oxygen atoms, forming the complex structure of aluminosilicate crystals. When added to the hardening solution as inorganic nanoparticles, aluminosilicate crystals can effectively fill the micropores on the surface of the hardened layer, thereby improving the density and wear resistance of the hardened layer.

[0031] Preferably, the inorganic nanoparticles are composed of nano-SiO2, nano-Al2O3, and aluminosilicate crystals in a weight ratio of 1:(1-2):(2-5).

[0032] When nano-SiO2, nano-Al2O3, and aluminosilicate crystals are compounded in a weight ratio of 1:(1-2):(2-5), a synergistic effect is achieved, and the hardened layer is further endowed with more excellent hardness and wear resistance; the ratio of inorganic nanoparticles further optimizes the wear resistance and anti-scratch performance, and enhances the comprehensive protective effect of the product.

[0033] Preferably, the inorganic nanoparticles are modified inorganic nanoparticles, and the modified inorganic nanoparticles are composed of the following raw materials in the following weight percentages:

[0034] Methacrylate mono-terminated dimethylpolysiloxane 3-8%

[0035] 0.5-3 parts of 3-(methoxydimethylsilyl)propyl acrylate 1-3 parts of polyethylene glycol succinimide methacrylate

[0036] 3-(2,3-Epoxypropyloxy)propyltrimethoxysilane 5-10%

[0037] The balance is inorganic nanoparticles.

[0038] By adopting the above technical scheme, the modified inorganic nanoparticles can significantly improve the wear resistance and comprehensive mechanical properties of the hardened layer. Methacrylate mono-terminated dimethylpolysiloxane improves the dispersibility of the nanoparticles in the hardening liquid and the bonding strength with the polymer matrix. 3-(methoxydimethylsilyl)propyl acrylate enhances the interfacial compatibility. Methacrylate polyethylene glycol succinimide ester improves the hardness after curing. 3-(2,3-epoxypropoxy)propyltrimethoxysilane further strengthens the bonding between the nanoparticles and the resin matrix, thereby making the protective film have excellent high hardness and high wear resistance.

[0039] In summary, the present application further improves the compatibility and dispersibility of inorganic nanoparticles in the raw material system by compounding mono-terminated dimethylpolysiloxane of acrylate, 3-(methoxydimethylsilyl)propyl acrylate, methacrylate polyethylene glycol succinimide ester, and 3-(2,3-epoxypropoxy)propyltrimethoxysilane, and can further cross-link with multifunctional polyurethane acrylate to further improve the wear resistance, hardness and anti-warping effect of the protective film.

[0040] In a second aspect, the present application provides a method for preparing a high-hardness and high-wear-resistant protective film, which is prepared by the following method:

[0041] 1) Weighing 30-50 parts of an acrylate polymer, 0.5-2 parts of a photoinitiator, 0.05-0.2 parts of a thermal initiator, 0.2-0.8 parts of an auxiliary agent, 30-50 parts of a solvent, and 3-10 parts of inorganic nanoparticles, and mixing them uniformly to obtain a hardening solution;

[0042] 2) Applying a hardening liquid to a thickness of 3-5 μm on the PET substrate, heat curing at 80°C-100°C for 1-3 minutes, and then UV curing to fully cure the liquid, thereby forming a hardened layer on the PET substrate; applying an adhesive to the second protective layer, heat curing at 130-160°C for 3-5 minutes, thereby forming an adhesive layer on the protective layer;

[0043] 3) Apply the secondary curing adhesive to the side of the PET substrate away from the hardened layer, heat to 140-160°C, and cure for 4-8 minutes to form a secondary curing layer. Then, laminate the secondary curing layer to the adhesive layer, roll it up, and store it in a dark place.

[0044] When using the protective film, peel off the release layer, attach the protective film to the screen, and then UV cure it to obtain a high-hardness and wear-resistant protective film.

[0045] By adopting the above technical solution, the high-hardness and high-wear-resistant protective film and its preparation method provided by the present invention achieve extremely high hardness and excellent wear resistance of the hardened layer while maintaining a relatively low coating thickness, effectively overcoming the serious warping problem of the hardened film caused by the thickening of the coating in the prior art.

[0046] Specifically, by controlling the type and ratio of acrylate polymers, especially introducing a specific proportion of inorganic nanoparticles, the hardened layer not only has high hardness, but also maintains good wear resistance and anti-warping properties, thereby significantly improving the overall quality of the screen protector and user experience.

[0047] The process of the present application can facilitate the processing and maintenance of the product. For example, in process 3), the secondary cured layer formed by thermal curing is stably adhered to the adhesive layer, which is convenient for storage and can also avoid premature contact with the hardened layer, thereby reducing warping during the production process. After being bonded to the hardened layer, it is cured again. When the secondary cured layer is photocured, it is further tightly connected with the hardened layer and the adhesive layer, thereby improving the stability of the layer structure and obtaining a better anti-warping effect.

[0048] In summary, this application includes at least one of the following beneficial technical effects:

[0049] 1. By optimizing the hardening layer formula and controlling the coating thickness within the range of 3-5μm, the protective film not only has ultra-high hardness (≥9H), but also can effectively resist long-term friction and wear, significantly improving wear resistance;

[0050] 2. The improved design and reasonable thickness control of the hardened layer avoids severe warping caused by coating thickening, ensures the stability and reliability of the product in the industrial production process, and expands its application range;

[0051] 3. The comprehensive mechanical properties of the coating are enhanced by adding a specific proportion of acrylic polymers and an appropriate amount of inorganic nanoparticles, further improving the scratch resistance of the protective film and enhancing the actual user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 This is a layer structure of a high-hardness and high-wear-resistant protective film of the present application;

[0053] Description of reference numerals:

[0054] 1. First protective layer; 2. Hardening layer; PET layer; 4. Secondary curing layer; 5. Adhesive layer; 6. Second protective layer. DETAILED DESCRIPTION

[0055] The following is combined with Figure 1 The present application is further described in detail with reference to the accompanying drawings and examples.

[0056] Introduction of some raw materials;

[0057] The difunctional polyurethane acrylate is aliphatic difunctional polyurethane acrylate UV4327, manufactured by Hunan Unico Chemical Technology Co., Ltd.

[0058] The preferred manufacturer of hexafunctional polyurethane acrylate is Jining Fangyu Chemical Co., Ltd., model RJ423;

[0059] Pentafunctional polyurethane acrylate is a 15-functional aliphatic polyurethane acrylate, and the manufacturer is preferably RJ4219 from Jining Fangyu Chemical Co., Ltd.;

[0060] The number average molecular weight of methacrylate mono-terminated dimethylpolysiloxane and methacrylate polyethylene glycol succinimide ester is 500-1000;

[0061] The particle size of nano-SiO2, nano-Al2O3, and aluminosilicate crystals are all 50-500nm;

[0062] The adhesive is acrylic glue model JD-9180 produced by Dongguan Jiudian Adhesive Co., Ltd.

[0063] The secondary curing adhesive is obtained by mixing 5% tripropylene glycol diacrylate, 15% 1,6-hexanediol dimethacrylate, 30% methyl methacrylate, 1% benzoyl peroxide, 48% PM, and 1% benzophenone.

[0064] Example

[0065] Example 1

[0066] A high hardness and high wear-resistant protective film, such as Figure 1 As shown, the high-hardness and high-wear-resistant protective film is provided with a first protective layer 1, a hardening layer 2, a PET layer 3, a secondary curing layer 4, an adhesive layer 5 and a second protective layer 6 in sequence from the upper surface to the lower surface; the hardening layer 2 is formed by applying a hardening liquid on the surface of the PET layer 3 and curing it, wherein the thickness of the PET layer 3 can be 30μm, 45μm, 50μm or 60μm, and preferably 50μm in this embodiment; the thickness of the secondary curing layer 4 can be 50μm, 60μm, 70μm or 80μm, and preferably 60μm in this embodiment; the thickness of the adhesive layer 5 can be 65μm, 70μm, 80μm, 90μm, 100μm or 115μm, and preferably 80μm in this embodiment.

[0067] The high hardness and high wear-resistant protective film is prepared by the following method:

[0068] 1) Weighing 30 parts of acrylate polymer, 0.5 parts of photoinitiator, 0.2 parts of thermal initiator, 0.2 parts of auxiliary agent, 30 parts of solvent and 10 parts of inorganic nanoparticles, and mixing them uniformly to obtain a hardening solution;

[0069] 2) Applying a hardening liquid to a thickness of 5 μm on a PET substrate, heat-curing at 80°C for 3 minutes, and then UV curing for 60 seconds to fully cure the liquid, thereby forming a hardened layer on the PET substrate; applying an adhesive to the second protective layer, heat-curing at 160°C for 3 minutes, thereby forming an adhesive layer on the protective layer;

[0070] 3) Apply the secondary curing adhesive to the side of the PET substrate away from the hardened layer, heat to 140°C, and cure for 8 minutes to form a secondary curing layer. Then, laminate the secondary curing layer to the adhesive layer, roll it up, and store it in a dark place.

[0071] When using the protective film, peel off the release layer, attach the protective film to the screen, and then UV cure for 60 seconds to obtain a high-hardness and wear-resistant protective film.

[0072] The above UV curing is carried out by UV lamp irradiation, and the UV lamp energy is 300mj / cm 2 .

[0073] The acrylate polymer consists of difunctional polyurethane acrylate and hexafunctional polyurethane acrylate in a weight ratio of 1:1.

[0074] The photoinitiator is benzophenone. The thermal initiator is benzoyl peroxide. The solvent is EA. The inorganic nanoparticles are nano-SiO2.

[0075] The auxiliary agent is an anti-settling agent (brand: Hemingway THIXATROL ST modified hydrogenated castor oil derivative).

[0076] Example 2

[0077] The difference between Example 2 and Example 1 is that the high hardness and high wear-resistant protective film is prepared by the following method:

[0078] 1) Weighing 40 parts of an acrylate polymer, 1 part of a photoinitiator, 0.1 part of a thermal initiator, 0.5 part of an auxiliary agent, 35 parts of a solvent, and 5 parts of inorganic nanoparticles, and mixing them uniformly to obtain a hardening solution;

[0079] 2) Applying a hardening liquid to a thickness of 4 μm on a PET substrate, heat-curing at 90°C for 4 minutes, and then UV curing for 60 seconds to fully cure the film, thereby forming a hardened layer on the PET substrate; applying an adhesive to the second protective layer, heat-curing at 150°C for 4 minutes, thereby forming an adhesive layer on the protective layer;

[0080] 3) Apply the secondary curing adhesive to the side of the PET substrate away from the hardened layer, heat to 150°C, and cure for 4 minutes to form a secondary curing layer on the release layer. Then, laminate the secondary curing layer to the adhesive layer, roll it up, and store it in a dark place.

[0081] When using the protective film, peel off the release layer, attach the protective film to the screen, and then UV cure for 60 seconds to obtain a high-hardness and wear-resistant protective film.

[0082] (The rest is the same as Example 1)

[0083] Example 3

[0084] The difference between Example 3 and Example 1 is that the high hardness and high wear-resistant protective film is prepared by the following method:

[0085] 1) Weighing 50 parts of an acrylate polymer, 2 parts of a photoinitiator, 0.05 parts of a thermal initiator, 0.8 parts of an auxiliary agent, 50 parts of a solvent, and 3 parts of inorganic nanoparticles, and mixing them uniformly to obtain a hardening solution;

[0086] 2) Applying a hardening liquid to a thickness of 3 μm on a PET substrate, heat-curing at 100°C for 3 minutes, and then UV curing for 60 seconds to fully cure the liquid, thereby forming a hardened layer on the PET substrate; applying an adhesive to the second protective layer, heat-curing at 160°C for 3 minutes, thereby forming an adhesive layer on the protective layer;

[0087] 3) Apply the secondary curing adhesive to the side of the PET substrate away from the hardened layer, heat to 140°C, and cure for 3 minutes to form a secondary curing layer on the release layer. Then, laminate the secondary curing layer to the adhesive layer, roll it up, and store it in a dark place.

[0088] When using the protective film, peel off the release layer, attach the protective film to the screen, and then UV cure for 60 seconds to obtain a high-hardness and wear-resistant protective film.

[0089] (The rest is the same as Example 1)

[0090] Example 4

[0091] The difference between Example 4 and Example 2 is that the acrylate polymer is composed of difunctional polyurethane acrylate and pentafunctional polyurethane acrylate in a weight ratio of 1:1.

[0092] Example 5

[0093] The difference between Example 5 and Example 2 is that the acrylate polymer is composed of hexafunctional polyurethane acrylate and pentafunctional polyurethane acrylate in a weight ratio of 1:1.

[0094] Example 6

[0095] The difference between Example 6 and Example 2 is that the acrylate polymer is composed of difunctional polyurethane acrylate, hexafunctional polyurethane acrylate, and pentafunctional polyurethane acrylate in a weight ratio of 1:1:0.3.

[0096] Example 7

[0097] The difference between Example 7 and Example 2 is that the acrylate polymer is composed of difunctional polyurethane acrylate, hexafunctional polyurethane acrylate, and pentafunctional polyurethane acrylate in a weight ratio of 1:2:1.

[0098] Example 8

[0099] The difference between Example 8 and Example 2 is that the acrylate polymer is composed of difunctional polyurethane acrylate, hexafunctional polyurethane acrylate, and pentafunctional polyurethane acrylate in a weight ratio of 1:5:1.5.

[0100] Example 9

[0101] The difference between Example 9 and Example 7 is that the inorganic nanoparticles are nano-Al2O3.

[0102] Example 10

[0103] The difference between Example 10 and Example 7 is that the inorganic nanoparticles are aluminosilicate crystals.

[0104] Example 11

[0105] The difference between Example 11 and Example 7 is that the inorganic nanoparticles are composed of nano-SiO2 and nano-Al2O3 in a weight ratio of 0.8:1.

[0106] Example 12

[0107] The difference between Example 12 and Example 7 is that the inorganic nanoparticles are composed of nano-SiO2, nano-Al2O3, and aluminosilicate crystals in a weight ratio of 1:1:5.

[0108] Example 13

[0109] The difference between Example 13 and Example 7 is that the inorganic nanoparticles are composed of nano-SiO2, nano-Al2O3, and aluminosilicate crystals in a weight ratio of 1:2:4.

[0110] Example 14

[0111] The difference between Example 14 and Example 7 is that the inorganic nanoparticles are composed of nano-SiO2, nano-Al2O3, and aluminosilicate crystals in a weight ratio of 1:1:3.

[0112] Example 15

[0113] The difference between Example 15 and Example 13 is that the inorganic nanoparticles are modified inorganic nanoparticles, and the modified nanoparticles are prepared by the following method:

[0114] According to weight percentage, 3% of methacrylate mono-terminated dimethylpolysiloxane, 0.5% of 3-(methoxydimethylsilyl)propyl acrylate, 1% of methacrylate polyethylene glycol succinimide ester, 10% of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 85.5% of inorganic nanoparticles were weighed and placed in a stirring device. The mixture was stirred at a speed of 100 r / min for 30 minutes to fully mix the mixture to obtain modified nanoparticles.

[0115] Example 16

[0116] The difference between Example 16 and Example 15 is that the modified nanoparticles are prepared by the following method:

[0117] According to weight percentage, 5% of methacrylate mono-terminated dimethylpolysiloxane, 2% of 3-(methoxydimethylsilyl)propyl acrylate, 2% of methacrylate polyethylene glycol succinimide ester, 7% of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 84% of inorganic nanoparticles were weighed and placed in a stirring device. The mixture was stirred at a speed of 100 r / min for 30 minutes to fully mix the mixture and obtain modified nanoparticles.

[0118] Example 17

[0119] The difference between Example 17 and Example 15 is that the modified nanoparticles are prepared by the following method:

[0120] According to weight percentage, 8% of methacrylate mono-terminated dimethylpolysiloxane, 3% of 3-(methoxydimethylsilyl)propyl acrylate, 1% of methacrylate polyethylene glycol succinimide ester, 5% of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and 83% of inorganic nanoparticles were weighed and placed in a stirring device. The mixture was stirred at a speed of 100 r / min for 30 minutes to fully mix the mixture to obtain modified nanoparticles.

[0121] Example 18

[0122] The difference between Example 18 and Example 15 is that methacrylate polyethylene glycol succinimide ester is replaced by 3-(methoxydimethylsilyl)propyl acrylate in an equal amount.

[0123] Example 19

[0124] The difference between Example 19 and Example 15 is that 3-(methoxydimethylsilyl)propyl acrylate is replaced by 3-(2,4-epoxypropoxy)propyltrimethoxysilane in an equal amount.

[0125] Example 20

[0126] The difference between Example 20 and Example 15 is that methacrylate mono-terminated dimethylpolysiloxane is replaced by 3-(2,4-epoxypropoxy)propyltrimethoxysilane in an equal amount.

[0127] Example 21

[0128] The difference between Example 21 and Example 15 is that methacrylate mono-terminated dimethylpolysiloxane and methacrylate polyethylene glycol succinimide ester are replaced by 3-(2,3-epoxypropoxy)propyltrimethoxysilane in equal amounts.

[0129] Comparative Example

[0130] Comparative Example 1

[0131] The difference between Comparative Example 1 and Example 1 is that the acrylate polymer is difunctional polyurethane acrylate.

[0132] Comparative Example 2

[0133] The difference between Comparative Example 2 and Example 1 is that the acrylate polymer is hexafunctional polyurethane acrylate.

[0134] Comparative Example 3

[0135] The difference between Comparative Example 3 and Example 1 is that the acrylate polymer is pentafunctional polyurethane acrylate.

[0136] Comparative Example 4

[0137] The difference between Comparative Example 4 and Example 1 is that the coating thickness is 10 μm.

[0138] Comparative Example 5

[0139] The difference between Comparative Example 5 and Example 1 is that the coating thickness is 1 μm.

[0140] Comparative Example 6

[0141] The difference between Comparative Example 6 and Example 1 is that the inorganic nanoparticles are replaced with acrylate polymers.

[0142] Performance testing

[0143] Pencil Hardness: Remove the protective layer from the protective films obtained in Examples 1-21 and Comparative Examples 1-6, and adhere the adhesive layer to TP (AF-coated glass, water drop angle 115-120°). Using a Mitsubishi test pencil lead of corresponding hardness, apply five 5-cm long strokes on the surface of the hardened layer at a pressure of 500 gf and a 45-degree angle between the pencil lead and the test surface.

[0144] Wear resistance test method: Tear off the protective layer of the protective film obtained in Examples 1-21 and Comparative Examples 1-6, and use special steel wool (steel wool model: #0000) to apply a load of 1 kg and a 2*2 cm indenter. Rub back and forth on the surface of the hardened layer at a speed of 50 times / min and a stroke of 20 mm until wear occurs, and record the corresponding number of times.

[0145] Edge warping test: The protective films obtained in Examples 1-21 and Comparative Examples 1-6 were cut into 7×14 cm sheets, the protective layer was torn off, and then the sheets were placed on a flat surface with the hardened layer facing downward for 10 minutes. The heights of the four corners above the horizontal plane were measured, and the average height was taken.

[0146] Film surface phenomena: Observe the surfaces of Examples 1-21 and Comparative Examples 1-6 to see whether shrinkage, whitening, etc. occur, and record the corresponding phenomena.

[0147] The above data are detailed in Table 1;

[0148] Table 1 Experimental data of Examples 1-21 and Comparative Examples 1-6

[0149]

[0150]

[0151] Combining Example 1 with Comparative Examples 1-6 and Table 1, it can be seen that the hardness of Comparative Examples 1-2 and Comparative Examples 5-6 is lower than that of Example 1, the wear times of Comparative Examples 1-3 and Comparative Example 5 are lower than that of Example 1, and the warpage heights of Comparative Examples 1-4 are higher than that of Example 1, while shrinkage occurs in Example 3. It can be seen that the raw material composition and coating thickness of the hardening layer of the present application can achieve better overall performance, thereby making the protective film simultaneously possess the characteristics of high wear resistance, high hardness, and low warpage.

[0152] Comparing Example 2 and Example 6 and combining them with Table 1, it can be seen that the wear resistance times of Example 6 are increased, the warpage height is reduced, and the hardness remains unchanged, indicating that when the difunctional polyurethane acrylate, the hexafunctional polyurethane acrylate, and the pentafunctional polyurethane acrylate are compounded, a synergistic effect is achieved, further improving the overall performance.

[0153] By comparing Example 7 and Example 12 and combining them with Table 1, it can be seen that the wear resistance times of Example 12 are increased, the warping height is reduced, and the hardness remains unchanged, indicating that when nano-SiO2, nano-Al2O3, and aluminosilicate crystals are compounded, a synergistic effect is achieved and better comprehensive performance is obtained.

[0154] By comparing Example 13, Examples 18-21 and Example 15 and combining them with Table 1, it can be seen that the wear resistance of Example 15 increases, the warping height decreases, and the hardness increases, indicating that the use of methacrylate mono-terminated dimethylpolysiloxane, 3-(methoxydimethylsilyl)propyl acrylate, methacrylate polyethylene glycol succinimide ester, and 3-(2,3-epoxypropoxy)propyltrimethoxysilane compound, and then modifying the inorganic nano-ions, can not only improve its dispersibility, but also react with the raw material system to improve the comprehensive performance of the protective film.

[0155] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A high hardness and high wear-resistant protective film, characterized in that: The high-hardness and high-wear-resistant protective film is provided with a first protective layer (1), a hardening layer (2), a PET layer (3), a secondary curing layer (4), an adhesive layer (5) and a second protective layer (6) in sequence from the upper surface to the lower surface; the hardening layer (2) is formed by coating a hardening liquid with a coating thickness of 3-5 μm on the surface of the PET layer (3) and curing; the hardening liquid is composed of the following raw materials in parts by weight: 30-50 parts of acrylic polymer 0.5-2 parts of photoinitiator Thermal initiator 0.05-0.2 parts 0.2-0.8 parts of additives 30-50 parts solvent 3-10 parts of modified inorganic nanoparticles; The acrylate polymer is composed of difunctional polyurethane acrylate, hexafunctional polyurethane acrylate, and pentafunctional polyurethane acrylate in a weight ratio of 1: (1-5): (0.3-1.5); The modified inorganic nanoparticles are composed of the following raw materials in percentage by weight: Methacrylate mono-terminated dimethylpolysiloxane 3-8% 3-(Methoxydimethylsilyl)propyl acrylate 0.5-3% Polyethylene glycol succinimide methacrylate 1-3% 3-(2,3-Epoxypropyloxy)propyltrimethoxysilane 5-10% The balance is inorganic nanoparticles; The inorganic nanoparticles are composed of nano-SiO2, nano-Al2O3 and aluminosilicate crystals in a weight ratio of 1: (1-2): (2-5).

2. The high-hardness and high-wear-resistant protective film according to claim 1, characterized in that: The auxiliary agent is one or more of a wetting agent, an antioxidant, a dispersant, and an anti-settling agent.

3. The high-hardness and high-wear-resistant protective film according to claim 1, characterized in that: The photoinitiator is an acetophenone photoinitiator.

4. The high-hardness and high-wear-resistant protective film according to claim 1, characterized in that: The thermal initiator is a peroxide thermal initiator and / or an azo thermal initiator.

5. The high-hardness and high-wear-resistant protective film according to claim 1, characterized in that: The solvent is composed of one or more of PM, MIBK, BA, and EA.

6. A method for preparing a high-hardness and high-wear-resistant protective film according to claim 1, characterized in that: Prepared by the following method: 1) Weighing 30-50 parts of an acrylate polymer, 0.5-2 parts of a photoinitiator, 0.05-0.2 parts of a thermal initiator, 0.2-0.8 parts of an auxiliary agent, 30-50 parts of a solvent, and 3-10 parts of modified inorganic nanoparticles, and mixing them uniformly to obtain a hardening solution; 2) Apply a hardening liquid to a thickness of 3-5 μm on the PET substrate, heat cure at 80-100°C for 1-3 minutes, and then perform UV curing to fully cure it, forming a hardened layer on the PET substrate; apply an adhesive to the second protective layer, heat cure at 130-160°C for 3-5 minutes, and form an adhesive layer on the protective layer; 3) Apply the secondary curing adhesive to the side of the PET substrate away from the hardened layer, heat to 140-160°C, and cure for 4-8 minutes to form a secondary curing layer. Then, laminate the secondary curing layer to the adhesive layer, roll it up, and store it in a dark place. When using the protective film, peel off the release layer, attach the protective film to the screen, and then UV cure it to obtain a high-hardness and wear-resistant protective film.

Images