Preparation method of angle-free UV curing shaping protective film

Abstract

The invention relates to a preparation method of an angle-free UV curing shaping protective film. Comprising a film body, and the film body is sequentially provided with a self-repairing layer, a polyurethane acrylate layer, a UV secondary curing layer and a bonding layer from the upper surface to the lower surface; the self-repairing layer is formed by coating the polyurethane acrylate layer with organic silicon modified polyurethane acrylate and curing the organic silicon modified polyurethane acrylate; the organic silicon modified polyurethane acrylate comprises polyurethane acrylate, alkyl hydroxyl polydimethylsiloxane, methyl methacrylate, a silane coupling agent, a photoinitiator, a defoaming agent and a solvent; the UV secondary curing layer is formed by coating polyol modified acrylic resin on the polyurethane acrylate layer and curing, and the polyol modified acrylic resin consists of polyol, methyl methacrylate, butyl acrylate, a photoinitiator, a solvent and a flatting agent. The protective film can be tightly attached to the curved screen, the phenomena of white edges and edge warping are avoided, and meanwhile the protective film has good flexibility and scratch resistance.

Description

Technical Field

[0001] The present application relates to the field of protective films, and more specifically, to a method for preparing an angle-free UV-curable fixed protective film. Background Art

[0002] As a common electronic product accessory, screen protectors are widely used in devices such as smartphones and tablets to protect screens from scratches, bumps, and other damage. With the continuous development of smart terminal devices, screen sizes are gradually increasing, and screen shapes are also developing from traditional flat screens to curved screens. This trend places higher requirements on the performance of screen protectors, especially for the applicability and protection effect of curved screens.

[0003] At present, the common screen protective films on the market mainly include PET hardened protective film, tempered glass protective film, TPU protective film and post-curing protective film. Although the PET hardened protective film has a lower cost, it is only suitable for flat screens and cannot meet the needs of curved screens. Although the tempered glass protective film has high hardness and transparency, due to its high requirements for the flatness of the glass surface, it has a high defect rate when fitted to large curved screens, and there are problems of fragility and sharp edges. Although the TPU protective film has good flexibility and impact resistance, the material is prone to nail scratches and has a strong odor. The post-curing protective film improves the overall performance of the protective film through a multi-layer structure design, but it is easy to produce white edges when fitted to large curved screens, and the multi-layer structure has a greater impact on the fingerprint unlocking under the screen, resulting in a decrease in the unlocking sensitivity.

[0004] In the prior art, in order to improve the adaptability and protective effect of screen protective films on curved screens, flexible materials such as PU are usually used to form a protective layer on the PET surface. However, during use, there are still phenomena such as scratches, white edges or warping edges, which reduces the practicality of the protective film. Therefore, a new technical solution is urgently needed to overcome these problems. Summary of the invention

[0005] In order to reduce the occurrence of warping and white edges, improve the lamination stability of the protective film and the curved screen, and reduce the occurrence of tearing and scratching of the protective film during use, a non-angle UV curing stereotyped protective film and a preparation method are provided. In a first aspect, the present application provides a UV curing shaping protective film without angles, comprising a film body, wherein the film body is provided with a self-repairing layer, a polyurethane acrylate layer, a UV secondary curing layer, and a bonding layer in sequence from the upper surface to the lower surface; The self-repairing layer is formed by coating a polyurethane acrylate layer with organosilicon-modified polyurethane acrylate and curing the layer. The organosilicon-modified polyurethane acrylate is prepared by the following raw materials in parts by weight: 50-55 parts of polyurethane acrylate, 15-20 parts of alkylhydroxy polydimethylsiloxane, 5-7 parts of methyl methacrylate, 0.5-1 parts of silane coupling agent, 2-4 parts of photoinitiator, 3-4 parts of defoamer, and 17-21 parts of solvent; The UV secondary curing layer is formed by coating a polyol-modified acrylic resin on a polyurethane acrylate layer and curing the polyol-modified acrylic resin. The polyol-modified acrylic resin is composed of the following raw materials in parts by weight: 45-60 parts of polyol, 35-40 parts of methyl methacrylate, 5-10 parts of butyl acrylate, 1-3 parts of photoinitiator, 20-30 parts of solvent, and 3-5 parts of leveling agent.

[0006] The angle-free UV-curable protective film of the present application can not only effectively solve the problems of white edges and warping edges when the existing protective film is used on curved screens, but also has better scratch resistance and flexibility, etc., reducing the possibility of scratches and damage to the protective film during use.

[0007] Specifically, by compounding polyurethane acrylate, alkylhydroxy polydimethylsiloxane, methyl methacrylate, and silane coupling agent, alkylhydroxy polydimethylsiloxane can improve flexibility, while the introduction of methyl methacrylate can further improve transmittance and hardness. The raw materials cooperate with each other to make the obtained silicone-modified polyurethane acrylate a self-repairing material, which not only improves the scratch resistance and scratch resistance of the film, but also enhances the flexibility of the film, making it more suitable for curved screens.

[0008] The present application adopts a polyurethane acrylate layer to replace the traditional PET film as the substrate, which has better flexibility and stable adhesion with silicone-modified polyurethane acrylate, so that the protective film has better scratch resistance and flexibility.

[0009] This application uses polyol, methyl methacrylate, and butyl acrylate as reaction monomers for compounding, and obtains polyol-modified acrylic resin that can be cured twice, and the obtained UV secondary curing layer has better flexibility, and has better hardness after secondary full curing. In combination with the self-repairing layer and polyurethane acrylate, the protective film has better scratch resistance and flexibility. Since the UV secondary curing layer is attached to the curved screen and then subjected to secondary UV curing, the polyol-modified acrylic resin is fully cured, so it can fit tightly with the curved screen, and combined with the bonding effect of the adhesive layer, white edges, warping edges, and other phenomena can be avoided.

[0010] In summary, the organosilicon-modified polyurethane acrylate obtained by compounding alkylhydroxy polydimethylsiloxane, methyl methacrylate, polyurethane acrylate, etc., has a better self-repairing effect when used on the self-repairing layer formed on the polyurethane acrylate layer, reducing the possibility of scratches and breakages, and the polyol-modified acrylic resin obtained by compounding with polyols, methyl methacrylate, butyl acrylate, etc. is used on the other side of the polyurethane acrylate layer. The UV secondary curing layer formed has better flexibility and scratch resistance. Combined with the adhesive layer, when used on the curved screen, it is UV-cured again, so that the protective film can completely fit the curved screen, and has good scratch resistance, scratch resistance and high light transmittance characteristics, effectively avoiding white edge phenomenon, warping edge phenomenon, etc., and reducing the possibility of scratches and breakages. And there is no need to open corners in production, etc., which improves production efficiency.

[0011] Preferably, the polyurethane acrylate is one or more of difunctional polyurethane acrylate, tetrafunctional polyurethane acrylate and hexafunctional polyurethane acrylate.

[0012] The combination of polyurethane acrylates with different functionalities can effectively improve the mechanical properties and chemical stability of the film, enhance tear resistance and scratch resistance, while maintaining good flexibility and transparency to ensure the best fit on curved screens.

[0013] Preferably, the silane coupling agent is KH550 and / or KH792; and the defoaming agent is an organic silicon defoaming agent.

[0014] The interface bonding performance between the silicone-modified polyurethane acrylate and the polyurethane acrylate layer is improved, the overall stability and durability of the film are enhanced, and at the same time, the bubble generation during the coating process is effectively reduced, ensuring the surface flatness and optical properties of the film.

[0015] Preferably, the thickness of the polyurethane acrylate layer is 25-100 μm.

[0016] The thickness of the polyurethane acrylate layer is controlled within the range of 25-100μm, which can ensure that the protective film has good flexibility and tear resistance, effectively avoiding the problem of poor lamination caused by improper thickness, and is particularly suitable for the lamination needs of curved screens. At the same time, the polyurethane acrylate layer within this thickness range can also effectively reduce the occurrence of white edge phenomenon, improve the aesthetics of the screen and the user experience.

[0017] Preferably, the bonding layer is formed by coating and curing liquid silicone or acrylic glue.

[0018] By adopting the above technical solution, the protective film has excellent adhesion performance and can be firmly attached to various screen surfaces, especially curved screens, avoiding the white edge problem that traditional protective films are prone to on large curved screens. At the same time, the use of liquid silicone or acrylic glue improves the durability and anti-aging performance of the protective film and reduces the debonding phenomenon caused by failure of the adhesive layer.

[0019] Preferably, the polyol is a combination of pentaerythritol, polyoxypropylene glycol and trimethylolpropane.

[0020] The UV-curable protective film without angles has better mechanical properties and chemical stability. Specifically, the use of multiple types of pentaerythritol, polyoxypropylene glycol, and trimethylolpropane as polyols can significantly improve the flexibility, tear resistance, and adhesion stability of the polyol-modified acrylic resin with the polyurethane acrylate layer, making the protective film more durable and less prone to damage, while also being able to better meet the needs of fitting curved screens.

[0021] Preferably, the photoinitiator in the organosilicon-modified polyurethane acrylate and the photoinitiator in the polyol-modified acrylic resin are one or more of TPO, TPO-L, 907, ITX, and 184.

[0022] By adopting the above technical solution, it is ensured that the silicone-modified polyurethane acrylate and polyol-modified acrylic resin have good curing performance, which improves the overall performance of the entire protective film and makes it more stable and reliable in practical applications. The above initiators can effectively improve the photoinitiator efficiency, accelerate the curing speed, and reduce the curing time, thereby improving production efficiency. At the same time, choosing a suitable photoinitiator can further enhance the mechanical strength and weather resistance of the material and extend its service life.

[0023] Preferably, the methyl methacrylate is a methyl methacrylate complex, and the methyl methacrylate complex is composed of the following raw materials in percentage by weight: Hydroxyl modified vinyl chloride-vinyl acetate-maleic anhydride terpolymer resin 1-3% N,N-(4-methyl-1,3-phenylene)bismaleimide 5-8% Branched hydroxy polyester 0.5-2.5% The balance is methyl methacrylate.

[0024] Hydroxyl-modified vinyl chloride-vinyl acetate-maleic anhydride terpolymer resin, N,N-(4-methyl-1,3-phenylene) bismaleimide, and branched hydroxy polyester play a synergistic role and interact with methyl methacrylate. When used in silicone-modified polyurethane acrylate and / or polyol-modified acrylic resin, they all play a synergistic role, so that the self-repairing layer and UV secondary curing layer formed after curing have better scratch resistance and flexibility, and are stably bonded to the polyurethane acrylate layer, thereby improving the structural stability of the protection modification.

[0025] In summary, this technical solution effectively improves the bonding stability of the layer structure by optimizing the components of the methyl methacrylate complex, while significantly improving the overall scratch resistance, flexibility and tear resistance of the protective film. It is suitable for use in high-demand curved screen protection scenarios and reduces the occurrence of white edges, warping edges and other phenomena.

[0026] In a second aspect, a method for preparing a UV-curable protective film without an angle comprises the following steps: Organosilicon-modified polyurethane acrylate: polyurethane acrylate, alkylhydroxy polydimethylsiloxane, methyl methacrylate, silane coupling agent, photoinitiator, defoamer and solvent are weighed and mixed evenly to obtain organosilicon-modified polyurethane acrylate; Polyol-modified acrylic resin: weigh polyol, methyl methacrylate, butyl acrylate, photoinitiator, solvent and leveling agent in parts by weight and mix them evenly to obtain polyol-modified acrylic resin; Coating silicone-modified polyurethane acrylate on the polyurethane acrylate layer and curing the polyurethane acrylate layer to form a self-repairing layer; A polyol-modified acrylic resin is coated on one side of the polyurethane acrylate layer away from the self-repairing layer, and thermal curing is performed to form an incompletely cured UV secondary curing layer on the polyurethane acrylate layer to obtain a scratch-resistant composite layer; an adhesive glue is coated on one side of the UV secondary curing layer of the scratch-resistant composite layer to form an adhesive layer, and the adhesive layer is then attached to a curved screen and UV cured. At this time, the UV secondary curing layer is completely cured to obtain a UV-cured shaping protective film.

[0027] In the above process, when the protective film is used for a curved screen, there is no need to open corners, and it can be stably attached to the surface of the curved screen and fit tightly with it. Under the action of the UV lamp, the UV secondary curing layer is completely cured and shaped, so that it can be completely attached to the curved screen to avoid white edges, warping edges and the like.

[0028] Preferably, the coating thickness of the self-healing adhesive is 15-35 μm, the coating thickness of the secondary curing layer is 30-150 μm; and the coating thickness of the adhesive layer is 10-45 μm.

[0029] By adopting the above technical solution, the coating thickness of the self-repairing adhesive is 15-35μm, which ensures that the self-repairing layer has good self-repairing performance, while avoiding the problems of increased costs due to excessive thickness and poor self-repairing effect due to excessive thinness. The coating thickness of the secondary curing layer is 30-150μm, which effectively improves the scratch resistance and tear resistance of the protective film, while also ensuring good fit with the screen. The coating thickness of the adhesive layer is 10-45μm, which ensures the strong adhesion of the protective film to the curved screen, avoids the generation of bubbles and white edges, and improves the user experience.

[0030] In summary, this application has the following beneficial effects: 1. The silicone-modified polyurethane acrylate obtained by compounding alkylhydroxy polydimethylsiloxane, methyl methacrylate, polyurethane acrylate, etc., has a good self-repairing effect when used on the self-repairing layer formed on the polyurethane acrylate layer, reducing the possibility of scratches and breakages. The polyol-modified acrylic resin obtained by compounding with polyols, methyl methacrylate, butyl acrylate, etc. is used on the other side of the polyurethane acrylate layer. The UV secondary curing layer formed has good flexibility and scratch resistance. Combined with the adhesive layer, when used on the curved screen, it is UV-cured again, so that the protective film can completely fit the curved screen, and has good scratch resistance, scratch resistance and high light transmittance characteristics, effectively avoiding white edge phenomenon, warping edge phenomenon, etc., and reducing the possibility of scratches and breakages. And there is no need to open corners in production, etc., which improves production efficiency.

[0031] 2. Hydroxyl-modified vinyl chloride-vinyl acetate-maleic anhydride terpolymer resin, N,N-(4-methyl-1,3-phenylene) bismaleimide, and branched hydroxy polyester play a synergistic role and interact with methyl methacrylate. When used in silicone-modified polyurethane acrylate and / or polyol-modified acrylic resin, they all play a synergistic role, so that the self-repairing layer and UV secondary curing layer formed after curing have better scratch resistance and flexibility, and are stably bonded to the polyurethane acrylate layer, thereby improving the structural stability of the protection modification.

[0032] 3. The method of the present application does not require the opening of corners. The polyol-modified acrylic resin obtained by compounding polyols, methyl methacrylate, butyl acrylate, etc., is thermally cured to completely volatilize the solvent, so that the raw material is stably adhered to the polyurethane acrylate layer to form an incompletely cured UV secondary curing layer, so that when it is used for a curved screen, it can be stably attached to the surface of the curved screen and fit closely with it. Under the action of the UV lamp, the UV secondary curing layer is completely cured and shaped, so that it is completely attached to the curved screen to avoid white edges, warping edges, etc. The organosilicon-modified polyurethane acrylate obtained by compounding peralkylhydroxy polydimethylsiloxane, methyl methacrylate, polyurethane acrylate, etc. forms a self-repairing layer that interacts with the UV secondary curing layer and the polyurethane acrylate layer, further improving the scratch resistance and flexibility, and reducing the possibility of damage. DETAILED DESCRIPTION

[0033] The present application is further described in detail below in conjunction with embodiments.

[0034] The sources of some raw materials; The average molecular weight of the hydroxy-modified vinyl chloride-vinyl acetate-maleic anhydride terpolymer resin is 34,000 (calculated from the viscosity number), and the appearance is colorless and transparent. The components (weight percentage) are: vinyl chloride 83-85%, vinyl acetate 12-14%, maleic acid 2.8-3.2%; active functional group carboxyl 2.8-3.2%; K value 50-60; The brand model of branched hydroxy polyester is Covestro 670; The solvent is ethyl acetate; The brand model of silicone defoamer is Shengbang silicone SI-X101; The brand model of the leveling agent is BASF EFKA FL 3740; The difunctional polyurethane acrylate is aliphatic difunctional polyurethane acrylate UV4327, the manufacturer is Hunan Unico Chemical Technology Co., Ltd.; The tetrafunctional polyurethane acrylate was model YC4100 from Jining Tangyi Chemical Co., Ltd.; The preferred manufacturer of hexafunctional polyurethane acrylate is Jining Fangyu Chemical Co., Ltd., model RJ423; Alkylhydroxy polydimethylsiloxane manufacturer Wuhan Haorong Biotechnology Co., Ltd., viscosity 1500CS; The preferred acrylic adhesive manufacturer is Dongguan Huirui Adhesive Co., Ltd., and the steel plate peeling force is 300-500g / inch.

[0035] Preparation Example of Methyl Methacrylate Complex Preparation Example 1 A methyl methacrylate compound is prepared by the following method: According to weight percentage, 1% hydroxy-modified vinyl chloride-vinyl acetate-maleic anhydride terpolymer resin, 8% N,N-(4-methyl-1,3-phenylene) bismaleimide, 0.5% branched hydroxy polyester, and 90.5% methyl methacrylate were weighed and mixed evenly to obtain a methyl methacrylate composite. Preparation Example 2-3 The difference between Preparation Example 2-3 and Preparation Example 1 is that the usage ratio of the raw materials is different, as shown in Table 1; Table 1 Raw material dosage of preparation examples 1-3 (%) Preparation Comparative Example Preparation Comparative Example 1 The difference between Preparation Comparative Example 1 and Preparation Example 1 is that the hydroxy-modified vinyl chloride-vinyl acetate-maleic anhydride terpolymer resin is replaced by methyl methacrylate in an equal amount.

[0036] Preparation Comparative Example 2 The difference between Preparation Comparative Example 2 and Preparation Example 1 is that an equal amount of N,N-(4-methyl-1,3-phenylene)bismaleimide is replaced by methyl methacrylate.

[0037] Preparation Comparative Example 3 The difference between Preparation Comparative Example 3 and Preparation Example 1 is that an equal amount of the branched hydroxy polyester is replaced by methyl methacrylate. Example

[0038] Example 1 A UV curing shaping protective film without angles, comprising a film body, wherein a self-repairing layer, a polyurethane acrylate layer, a UV secondary curing layer, and a bonding layer are sequentially arranged from the upper surface to the lower surface of the film body, wherein the self-repairing layer is formed by curing silicone-modified polyurethane acrylate. The angle-free UV-curable protective film is prepared by the following method: Organosilicon-modified polyurethane acrylate: weigh 50 kg of polyurethane acrylate, 15 kg of alkylhydroxy polydimethylsiloxane, 7 kg of methyl methacrylate, 0.8 kg of silane coupling agent, 2 kg of photoinitiator, 3 kg of defoamer, and 17 kg of solvent, and mix them evenly to obtain organosilicon-modified polyurethane acrylate; Polyol-modified acrylic resin: weigh 60 kg of polyol, 35 kg of methyl methacrylate, 10 kg of butyl acrylate, 1 kg of photoinitiator, 30 kg of solvent, and 3 kg of leveling agent and mix them evenly to obtain a polyol-modified acrylic resin; Mix difunctional polyurethane acrylate, tetrafunctional polyurethane acrylate and photoinitiator in a weight ratio of 10:10:0.3 and apply them on the release film. The curing energy is 1000mj / cm 2 The film was cured for 2 min and the release film was peeled off to obtain a polyurethane acrylate layer.

[0039] Silicone-modified polyurethane acrylate is coated on the polyurethane acrylate layer with a curing energy of 1000 mj / cm 2 The film was cured for 2 minutes to form a self-repairing layer on the polyurethane acrylate layer; Polyol-modified acrylic resin was coated on the side of the polyurethane acrylate layer away from the self-repairing layer, and thermal curing was performed at a curing temperature of 100°C for 2 minutes to completely evaporate the solvent, and an incompletely cured UV secondary curing layer was formed on the polyurethane acrylate layer to obtain a scratch-resistant composite layer; acrylic glue was coated on one side of the UV secondary curing layer of the scratch-resistant composite layer, and cured at 100°C for 2 minutes to form an adhesive layer, and then the adhesive layer was attached to a 6.67-inch curved screen and UV cured at a curing energy of 1000mj / cm 2 The UV secondary curing layer is completely cured to obtain a UV curing protective film.

[0040] The polyol is composed of 20 kg pentaerythritol, 15 kg polyoxypropylene glycol, and 15 kg trimethylolpropane.

[0041] The coating thickness of the self-repairing adhesive is 25 μm, the coating thickness of the secondary curing layer is 150 μm; the coating amount of the adhesive layer is 10 μm; the silane coupling agent is KH792; the defoamer is an organic silicon defoamer; the thickness of the polyurethane acrylate layer is 25 μm; and the bonding layer is formed by curing acrylic adhesive. The polyurethane acrylate is a difunctional polyurethane acrylate. The photoinitiator in the silicone-modified polyurethane acrylate and the photoinitiator in the polyol-modified acrylic resin are both TPO.

[0042] Embodiment 2-5 The difference between Example 2-5 and Example 2 is that the amount of the polyol-modified acrylic resin and the silicone-modified polyurethane acrylate and the thickness of the layer structure are different, as shown in Table 2; Table 2 Amounts of raw materials of polyol-modified acrylic resin and silicone-modified polyurethane acrylate in Examples 1, 2-5 (kg) Example 6 The difference between Example 6 and Example 2 is that the polyurethane acrylate is composed of tetrafunctional polyurethane acrylate and hexafunctional polyurethane acrylate in a weight ratio.

[0043] Examples 7-12 The difference between Examples 7-12 and Example 6 is that the methyl methacrylate in the silicone-modified polyurethane acrylate is a methyl methacrylate complex, and the source of the methyl methacrylate complex is specifically shown in Table 3; Table 3 Sources of methyl methacrylate complexes in silicone-modified polyurethane acrylic acid of Examples 7-12 Example Source of Methyl Methacrylate Complex Example 7 Preparation Example 1 Example 8 Preparation Example 2 Example 9 Preparation Example 3 Example 10 Preparation Comparative Example 1 Embodiment 11 Preparation Comparative Example 2 Example 12 Preparation Comparative Example 3 Examples 13-18 The difference between Examples 13-18 and Example 8 is that the methyl methacrylate in the polyol-modified acrylic resin is a methyl methacrylate complex, and the source of the methyl methacrylate complex is specifically shown in Table 4; Table 4 Sources of methyl methacrylate complexes in polyol-modified acrylic resins of Examples 13-18 Example Source of Methyl Methacrylate Complex Example 13 Preparation Example 1 Embodiment 14 Preparation Example 2 Embodiment 15 Preparation Example 3 Example 16 Preparation Comparative Example 1 Embodiment 17 Preparation Comparative Example 2 Embodiment 18 Preparation Comparative Example 3 Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that an equal amount of alkylhydroxy polydimethylsiloxane is replaced by polyurethane acrylate.

[0044] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the methyl methacrylate in the silicone-modified polyurethane acrylate is replaced by polyurethane acrylate in an equal amount.

[0045] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the methyl methacrylate in the polyol-modified acrylic resin is replaced by butyl acrylate in an equal amount.

[0046] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the polyurethane acrylate layer of equal thickness is replaced by a PET film.

[0047] Performance testing Detection method / test method Light transmittance and haze: Refer to GB / T 2410-2008 and use a light transmittance tester to test the light transmittance and haze.

[0048] Surface scratches: Cut into test samples (10 cm long and 10 cm wide), attach the test samples flatly on the steel plate, use a copper brush with a copper wire diameter of 0.1 mm to scratch back and forth on the surface of the scratch-resistant layer of the test sample (the scratching force is 5N), start the timer, record the time when the scratch disappears, repeat the test 3 times, and take the average value.

[0049] Appearance: Check whether the surface has peeling, warping, or white edges. If the above phenomena occur, it will be recorded as unqualified; Mechanical properties: The scratch-resistant composite layers obtained in Examples 1-18 and Comparative Examples 1-8 were cut into test samples, and the trouser-shaped tear strength test was carried out with reference to GB / T16578.1-2008.

[0050] The above experimental data are detailed in Table 5 Table 5 Examples 1-18 and Comparative Examples 1-4 Combining Example 1 and Comparative Examples 1-2 and Table 5, it can be seen that scratches occur in Comparative Examples 1-2, while the scratch recovery time in Example 1 is only 10 seconds, and the tear strength of Comparative Examples 1-2 is less than that of Example 1, and the haze and light transmittance of Example 1 do not change much, indicating that the silicone-modified polyurethane acrylate obtained by the polyurethane acrylate, alkylhydroxy polydimethylsiloxane, methyl methacrylate, silane coupling agent, photoinitiator, defoaming agent, and solvent of the present application has a self-repairing layer formed by coating, which has better tear resistance, scratch resistance, etc., and has better optical properties, reduces the tearing, breakage, warping, etc. of the UV-cured shaping protective film during use, and improves its practicality.

[0051] Combining Example 1 and Comparative Example 3 with Table 5, it can be seen that the scratch recovery time of Comparative Example 3 is longer, and the tear strength and light transmittance are lower, and the haze is higher, indicating that the present application uses methyl methacrylate and polyol for modification, which can further improve the structural stability and tear resistance of the protective film, reduce the occurrence of scratches, tearing, warping and the like, and improve its practicality.

[0052] Combining Example 1 and Comparative Example 4 with Table 5, it can be seen that the edge warping phenomenon occurs in Comparative Example 3, indicating that after the polyurethane acrylate layer of equal thickness is replaced with a PET film, it is easy to warp during use, affecting its practicality.

[0053] In combination with Example 7, Example 6, and Examples 10-12, it can be seen that Example 7 obtains higher tear strength and the surface scratch disappearance time is shortened, indicating that the compounding of hydroxy-modified vinyl chloride-vinyl acetate-maleic anhydride ternary copolymer resin, N,N-(4-methyl-1,3-phenylene) bismaleimide, branched hydroxy polyester, and methyl methacrylate plays a synergistic role and further improves the comprehensive performance of the protective film.

[0054] Combining Example 14 and Example 8 and Table 5, it can be seen that the glass tear strength of Example 14 is greater than the tear strength of Example 8, the scratch recovery time of Example 14 is shorter than that of Example 8, and the changes in transmittance, haze, etc. are not significant, indicating that by using a methyl methacrylate composite instead of methyl methacrylate, the obtained protective film has better scratch resistance, tear resistance and optical properties.

[0055] 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 modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A UV curing protective film without angle, comprising a film body, characterized in that: The film body is provided with a self-repairing layer, a polyurethane acrylate layer, a UV secondary curing layer, and a bonding layer in sequence from the upper surface to the lower surface; The self-repairing layer is formed by coating a polyurethane acrylate layer with organosilicon-modified polyurethane acrylate and curing the layer. The organosilicon-modified polyurethane acrylate is prepared by the following raw materials in parts by weight: 50-55 parts of polyurethane acrylate, 15-20 parts of alkylhydroxy polydimethylsiloxane, 5-7 parts of methyl methacrylate, 0.5-1 parts of silane coupling agent, 2-4 parts of photoinitiator, 3-4 parts of defoamer, and 17-21 parts of solvent; The UV secondary curing layer is formed by coating a polyol-modified acrylic resin on a polyurethane acrylate layer and curing the polyol-modified acrylic resin. The polyol-modified acrylic resin is composed of the following raw materials in parts by weight: 45-60 parts of polyol, 35-40 parts of methyl methacrylate, 5-10 parts of butyl acrylate, 1-3 parts of photoinitiator, 20-30 parts of solvent, and 3-5 parts of leveling agent.

2. The non-angle UV curing protective film according to claim 1, characterized in that: The polyurethane acrylate is one or more of difunctional polyurethane acrylate, tetrafunctional polyurethane acrylate and hexafunctional polyurethane acrylate.

3. The non-angle UV curing protective film according to claim 1, characterized in that: The silane coupling agent is KH550 and / or KH792; the defoaming agent is an organic silicon defoaming agent.

4. The non-angle UV curing protective film according to claim 1, characterized in that: The thickness of the polyurethane acrylate layer is 25-100 μm.

5. The non-angle UV curing protective film according to claim 1, characterized in that: The bonding layer is formed by coating and curing liquid silicone or acrylic glue.

6. The non-angle UV curing protective film according to claim 1, characterized in that: The polyol is a variety of pentaerythritol, polyoxypropylene glycol and trimethylolpropane.

7. The non-angle UV curing protective film according to claim 1, characterized in that: The photoinitiator in the organosilicon-modified polyurethane acrylate and the photoinitiator in the polyol-modified acrylic resin are one or more of TPO, TPO-L, 907, ITX, and 184.

8. The non-angle UV curing protective film according to any one of claims 1 to 7, characterized in that: The methyl methacrylate is a methyl methacrylate complex, and the methyl methacrylate complex is composed of the following raw materials in percentage by weight: Hydroxyl modified vinyl chloride-vinyl acetate-maleic anhydride terpolymer resin 1-3% N,N-(4-methyl-1,3-phenylene)bismaleimide 5-8% Branched hydroxy polyester 0.5-2.5% The balance was methyl methacrylate.

9. A method for preparing a UV curable protective film without angles as claimed in any one of claims 1 to 8, characterized in that: The following steps are involved: Organosilicon-modified polyurethane acrylate: polyurethane acrylate, alkylhydroxy polydimethylsiloxane, methyl methacrylate, silane coupling agent, photoinitiator, defoamer and solvent are weighed and mixed evenly to obtain organosilicon-modified polyurethane acrylate; Polyol-modified acrylic resin: weigh polyol, methyl methacrylate, butyl acrylate, photoinitiator, solvent and leveling agent in parts by weight and mix them evenly to obtain polyol-modified acrylic resin; Coating silicone-modified polyurethane acrylate on the polyurethane acrylate layer and curing the polyurethane acrylate layer to form a self-repairing layer; A polyol-modified acrylic resin is coated on one side of the polyurethane acrylate layer away from the self-repairing layer, and thermal curing is performed to form an incompletely cured UV secondary curing layer on the polyurethane acrylate layer to obtain a scratch-resistant composite layer; an adhesive glue is coated on one side of the UV secondary curing layer of the scratch-resistant composite layer to form an adhesive layer, and the adhesive layer is then attached to a curved screen and UV cured. At this time, the UV secondary curing layer is completely cured to obtain a UV-cured shaping protective film.

10. The method for preparing a UV curable protective film without angle according to claim 9, characterized in that: The coating thickness of the self-repairing adhesive is 15-35 μm, the coating thickness of the secondary curing layer is 30-150 μm; and the coating thickness of the adhesive layer is 10-45 μm.

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