Anti-aging vehicle-mounted OCA and preparation method thereof

Abstract

The invention relates to the field of optical cement, and particularly discloses an anti-aging vehicle-mounted OCA and a preparation method thereof. The anti-aging vehicle-mounted OCA is prepared from the following raw materials in parts by weight: 70-90 parts of organic silicon modified polyurethane acrylate, 15-25 parts of a diluting monomer, 3-8 parts of a photoinitiator and 1-3 parts of an antioxidant, the organic silicon modified polyurethane acrylate is prepared from hexafunctional group polyurethane acrylate, tetramethyl tetravinyl cyclotetrasiloxane, triisopropyl silyl methacrylate, a trifunctional group acrylate monomer, long-chain alkyl silane and a catalyst. The vehicle-mounted OCA prepared by the invention is suitable for bonding of an automobile electronic display screen, has relatively good ultraviolet resistance and temperature resistance after long-term use, has relatively good bonding stability, and is not easy to age and yellow.

Description

Technical Field

[0001] The present application relates to the field of optical adhesives, and more specifically, it relates to an aging-resistant vehicle-mounted OCA and its preparation method. Background Art

[0002] OCA optical adhesives have excellent flexibility, adhesion, and high transparency, so they are widely used in flexible vehicle-mounted displays.

[0003] In a vehicle-mounted environment, temperature changes and humidity changes may affect display devices. The OCA optical adhesive can fix various optical elements to form a stable display system, effectively resisting the above interference factors.

[0004] Currently, common vehicle-mounted OCA optical adhesives are generally prepared from polyurethane acrylate, diluent monomers, photoinitiators, and additives. Although they can have good flexibility and adhesiveness, the internal environment of automobiles is relatively harsh, with a large temperature range span and drastic temperature changes inside the vehicle; the humidity conditions are also unstable, and the vehicle-mounted display is under sunlight irradiation for a long time, so it is still prone to problems such as aging and yellowing and unstable adhesion, reducing the application stability of the vehicle-mounted OCA optical adhesive. Summary of the Invention

[0005] In order to solve the problems that vehicle-mounted OCA is prone to aging, yellowing, and unstable adhesion during long-term use, the present application provides an aging-resistant vehicle-mounted OCA and its preparation method.

[0006] In the first aspect, the present application provides an aging-resistant vehicle-mounted OCA, adopting the following technical solution: An aging-resistant vehicle-mounted OCA is prepared from the following raw materials in parts by weight: 70 - 90 parts of organosilicon-modified polyurethane acrylate 15 - 25 parts of diluent monomer 3 - 8 parts of photoinitiator 1 - 3 parts of antioxidant; The organosilicon-modified polyurethane acrylate is prepared from hexa-functional polyurethane acrylate, tetramethyltetravinylcyclotetrasiloxane, triisopropylsilyl methacrylate, trifunctional acrylate monomers, long-chain alkylsilane, and a catalyst.

[0007] By adopting the above technical solution, the vehicle-mounted OCA of the present application uses silicone-modified polyurethane acrylate as the adhesive system, and is compounded with an appropriate amount of diluent monomer, photoinitiator and antioxidant. The finally prepared vehicle-mounted OCA not only has excellent transparency, adhesiveness and flexibility, but also has good aging resistance and yellowing resistance, and is suitable for applications such as vehicle-mounted displays. Among them, the silicone-modified polyurethane acrylate prepared from hexafunctional polyurethane acrylate, tetramethyltetravinylcyclotetrasiloxane, triisopropylsilyl methacrylate, trifunctional acrylate monomer, long-chain alkylsilane and catalyst contains branched siloxane bonds and macromolecular network interwoven structures in the molecular chain segments, which improves the long-term heat resistance and ultraviolet light resistance of the prepared vehicle-mounted OCA, and significantly improves the aging resistance and yellowing resistance of the vehicle-mounted OCA.

[0008] Preferably, the silicone-modified polyurethane acrylate is prepared from the following raw materials in parts by weight: Hexafunctional polyurethane acrylate 40-60 parts Tetramethyltetravinylcyclotetrasiloxane 4-6 parts Triisopropylsilyl methacrylate 5-8 parts Trifunctional acrylate monomer 10-15 parts Long-chain alkylsilane 2-4 parts Catalyst 0.2-0.4 parts.

[0009] By adopting the above technical solution, the hexafunctional polyurethane acrylate acts together with tetramethyltetravinylcyclotetrasiloxane and triisopropylsilyl methacrylate to first introduce a branched silane structure into the molecular chain segments, while improving the mechanical properties of the vehicle-mounted OCA, improving the heat resistance and ultraviolet light resistance. The trifunctional acrylate monomer can further crosslink with the polyurethane acrylate, while improving the bonding strength and the processing stability of the system, it can further interweave with the system to form a dense molecular chain segment structure. The long-chain alkylsilane has a flexible long-chain silane structure, which can further interweave and disperse in the system, further improving the structural stability of the system, so that the prepared vehicle-mounted OCA still maintains excellent stability in the harsh automotive environment, effectively avoiding problems such as aging, yellowing and unstable bonding caused by high temperature, high humidity or long-term light exposure.

[0010] Preferably, the trifunctional acrylate monomer is composed of pentaerythritol triacrylate and ethoxylated trimethylolpropane triacrylate in a weight ratio of 1:(2-4).

[0011] By adopting the above technical solution, using trimethylolpropane triacrylate and ethoxylated trimethylolpropane triacrylate with an optimal weight ratio as trifunctional acrylate monomers can improve the crosslinking density of silicone-modified polyurethane acrylate, thereby enhancing the adhesion performance, aging resistance and yellowing resistance of the vehicle-mounted OCA with aging resistance.

[0012] Preferably, the long-chain alkylsilane is any one or a combination of dodecyltrimethoxysilane, dodecyltriethoxysilane, and hexadecyltrimethoxysilane.

[0013] By adopting the above technical solution, the long-chain alkylsilane can further enhance the hydrophobic and weather resistance of the silicone-modified polyurethane acrylate, thereby improving the service life and stability of the product.

[0014] Preferably, the catalyst is benzoyl peroxide or diisopropylbenzene peroxide.

[0015] By adopting the above technical solution, using benzoyl peroxide or diisopropylbenzene peroxide as the catalyst can effectively promote the reaction process, improve the reaction efficiency and product purity.

[0016] Preferably, the silicone-modified polyurethane acrylate is prepared by the following steps: Add the hexafunctional polyurethane acrylate, tetramethyltetravinylcyclotetrasiloxane, triisopropylsilyl methacrylate, trifunctional acrylate monomers, long-chain alkylsilane and catalyst into the reaction equipment, and react at a temperature of 70 - 80 °C for 1 - 2 h to obtain the silicone-modified polyurethane acrylate.

[0017] By adopting the above technical solution, reacting under optimal temperature and time conditions ensures that all components react fully while avoiding side reactions caused by high temperature, and finally makes the vehicle-mounted OCA prepared have excellent ultraviolet resistance, temperature resistance and anti-yellowing performance.

[0018] Preferably, the diluent monomer is composed of methyl methacrylate, lauryl methacrylate and glycidyl acrylate with a weight ratio of 1:(1 - 2):(1.5 - 2.5).

[0019] By adopting the above technical solution, using methyl methacrylate, lauryl methacrylate and glycidyl acrylate with an optimal weight ratio as the diluent monomer can further crosslink with the silicone-modified polyurethane acrylate, while ensuring good processing fluidity of the vehicle-mounted OCA, improving the comprehensive performance of the finally prepared vehicle-mounted OCA.

[0020] Preferably, the photoinitiator is 1-hydroxycyclohexyl phenyl ketone and / or 2-hydroxy-2-methyl-1-phenyl-1-propanone, and the antioxidant is antioxidant 1010 and / or antioxidant 168.

[0021] By adopting the above technical solutions, the preferred photoinitiator can significantly improve the efficiency and depth of ultraviolet curing, ensure rapid cross-linking and curing of the adhesive layer under light irradiation, and enhance the stability of the product. At the same time, the selection of antioxidant 1010 and / or antioxidant 168 can effectively capture free radicals and inhibit the oxidation degradation reaction caused by oxygen, thereby greatly improving the aging resistance of the vehicle-mounted OCA, reducing the yellowing phenomenon during long-term use, and extending the service life of the product.

[0022] In a second aspect, the present application provides a method for preparing an aging-resistant vehicle-mounted OCA, adopting the following technical solutions: A method for preparing an aging-resistant vehicle-mounted OCA includes the following steps: S1. Mix organosilicon-modified polyurethane acrylate, diluent monomer, photoinitiator and antioxidant evenly, and perform vacuum degassing to obtain an adhesive; S2. Coat the adhesive on the surface of the release film, first perform ultraviolet curing, then perform thermal curing, and wind up to obtain an aging-resistant vehicle-mounted OCA.

[0023] By adopting the above technical solutions, during the preparation process, after the raw materials are fully mixed and vacuum degassed, the residual bubbles are effectively reduced, and the quality stability of the adhesive is improved. Then, through the double-curing method of first ultraviolet curing and then thermal curing, the cross-linking density of the material is further enhanced, thereby significantly improving the ability of the vehicle-mounted OCA to resist extreme temperature changes and long-term sunlight irradiation, effectively avoiding the occurrence of aging and yellowing problems, and ensuring its good service life in the complex environment of the car; the release film plays a role in supporting and protecting the OCA optical adhesive, and is directly bonded and used by tearing off the release film during use.

[0024] Preferably, the thickness of the vehicle-mounted OCA is 50-350 μm.

[0025] By adopting the above technical solutions, the vehicle-mounted OCA with a relatively optimal thickness can enhance the structural stability without affecting the light transmittance, and improve the overall application reliability of the vehicle-mounted OCA.

[0026] In summary, the present application includes at least one of the following beneficial technical effects: 1. The anti-aging vehicle-mounted OCA of the present application is prepared from organosilicon-modified polyurethane acrylate, diluent monomer, photoinitiator and antioxidant. The organosilicon-modified polyurethane acrylate is prepared by reacting hexafunctional polyurethane acrylate, tetramethyltetravinylcyclotetrasiloxane, triisopropylsilyl methacrylate, trifunctional acrylate monomer, long-chain alkylsilane and catalyst. The prepared vehicle-mounted OCA has good adhesiveness, excellent heat resistance and ultraviolet performance, and is applied to automotive displays. It is not easy to age and turn yellow when used in a long-term complex environment.

[0027] 2. Using trimethylolpropane triacrylate and ethoxylated trimethylolpropane triacrylate with a relatively optimal weight ratio as the trifunctional acrylate monomer can improve the crosslinking density of the organosilicon-modified polyurethane acrylate, thereby enhancing the adhesiveness, anti-aging and yellowing resistance of the anti-aging vehicle-mounted OCA.

[0028] 3. The preparation method of the present application prepares an adhesive, coats the adhesive on a release film and cures and dries it. The prepared vehicle-mounted OCA has good optical properties, flexibility and adhesiveness, and can also have good anti-aging performance and anti-yellowing performance. Specific Embodiments

[0029] The following further elaborates on the present application with reference to examples.

[0030] The following are the sources and specifications of some raw materials of the present application. The raw materials used in the preparation examples and examples of the present application can all be obtained commercially, including but not limited to the raw materials of the following models and manufacturers. Raw materials with the same performance can all be used: 1. Hexafunctional polyurethane acrylate: Sartomer EBECRYL 1291N; 2. Tetramethyltetravinylcyclotetrasiloxane: CAS No. 2554-06-5, content 99%; 3. Triisopropylsilyl methacrylate: CAS No. 134652-60-1, content 99%.

[0031] Preparation Example of Organosilicon-Modified Polyurethane Acrylate Preparation Example 1 Preparation Example 1 discloses a silicone-modified polyurethane acrylate, which is prepared by the following steps: 4 kg of functional group polyurethane acrylate, 0.4 kg of tetramethyltetravinylcyclotetrasiloxane, 0.8 kg of triisopropylsilyl methacrylate, 1 kg of trifunctional acrylate monomer (composed of trimethylolpropane triacrylate and pentaerythritol triacrylate with a weight ratio of 2:1), 0.2 kg of dodecyltrimethoxysilane as a long-chain alkyl silane and 0.02 kg of benzoyl peroxide as a catalyst are added to a reaction kettle, and the reaction is carried out at a temperature of 70 °C for 2 h to obtain the silicone-modified polyurethane acrylate.

[0032] Preparation Examples 2-3 The differences between Preparation Examples 2-3 and Preparation Example 1 lie in the raw material dosages and preparation conditions. See Table 1 below for details.

[0033] Table 1 Parameter Table of Preparation Examples 1-3 Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that the trifunctional acrylate monomer is composed of pentaerythritol triacrylate and ethoxylated trimethylolpropane triacrylate with a weight ratio of 1:2, and the others are the same as Preparation Example 1.

[0034] Preparation Example 5 The difference between Preparation Example 5 and Preparation Example 1 is that the trifunctional acrylate monomer is composed of pentaerythritol triacrylate and ethoxylated trimethylolpropane triacrylate with a weight ratio of 1:4, and the others are the same as Preparation Example 1.

[0035] Preparation Comparative Example 1 The difference between Preparation Comparative Example 1 and Preparation Example 1 is that the hexafunctional group polyurethane acrylate is replaced with a difunctional group polyurethane acrylate in equal amount, commercially available, Zahn EBECRYL 8213, and the others are the same as Preparation Example 1.

[0036] Preparation Comparative Example 2 The difference between Preparation Comparative Example 2 and Preparation Example 1 is that the triisopropylsilyl methacrylate is replaced with tetramethyltetravinylcyclotetrasiloxane in equal amount, and the others are the same as Preparation Example 1.

[0037] Preparation Comparative Example 3 The difference between Preparation Comparative Example 3 and Preparation Example 1 lies in that the ethoxylated trimethylolpropane triacrylate is replaced with neopentyl glycol diacrylate in equal amount, and the others are the same as Preparation Example 1.

[0038] Preparation Comparative Example 4 The difference between Preparation Comparative Example 4 and Preparation Example 1 is that the dodecyltrimethoxysilane is replaced with vinyltrimethoxysilane in equal amount, and the others are the same as Preparation Example 1. Example

[0039] Example 1 Example 1 discloses an aging-resistant vehicle-mounted OCA, which is prepared by the following steps: S1. Mix 7 kg of the organosilicon-modified polyurethane acrylate prepared in Preparation Example 1, 1.5 kg of a diluent monomer (composed of methyl methacrylate, lauryl methacrylate, and glycidyl acrylate in a weight ratio of 1:1:1.5), 0.3 kg of 1-hydroxycyclohexyl phenyl ketone as a photoinitiator, and 0.1 kg of an antioxidant (composed of antioxidant 1010 and antioxidant 168 in a weight ratio of 2:1) evenly, and perform vacuum degassing to obtain an adhesive; S2. Coat the adhesive on the surface of a PET release film, first perform ultraviolet curing for 20 min under the condition of an ultraviolet curing energy of 800 mj / cm 2 , and then perform thermal curing for 60 min under the condition of a temperature of 80 °C to form an adhesive layer, and wind it up to obtain an aging-resistant vehicle-mounted OCA; the thickness of the vehicle-mounted OCA prepared in this application is 50 - 350 μm, and the thickness of the vehicle-mounted OCA in this example is 250 μm.

[0040] Examples 2 - 3 The differences between Examples 2 - 3 and Example 1 are that the preparation process parameters are different. For details, see Table 2.

[0041] Table 2 Parameter Table of Examples 1 - 3 Example 4 The difference between Example 4 and Example 1 is that the organosilicon-modified polyurethane acrylate in Example 4 is from Preparation Example 4, and the others are the same as Example 1.

[0042] Example 5 The difference between Example 5 and Example 1 is that the organosilicon-modified polyurethane acrylate in Example 5 is from Preparation Example 5, and the others are the same as Example 1.

[0043] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the organosilicon-modified polyurethane acrylate in Comparative Example 1 is from Preparation Comparative Example 1, and the others are the same as Example 1.

[0044] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the organosilicon-modified polyurethane acrylate in Comparative Example 2 is from Preparation Comparative Example 2, and the others are the same as Example 1.

[0045] Comparative Example 3 The difference between Comparative Example 3 and Example 1 is that the silicone-modified polyurethane acrylate in Comparative Example 3 is prepared from Comparative Example 3, and the others are the same as those in Example 1.

[0046] Comparative Example 4 The difference between Comparative Example 4 and Example 1 is that the silicone-modified polyurethane acrylate in Comparative Example 4 is prepared from Comparative Example 4, and the others are the same as those in Example 1.

[0047] Comparative Example 5 The difference between Comparative Example 5 and Example 1 is that the silicone-modified polyurethane acrylate in Comparative Example 5 is commercially available, with the brand name Tangyi and the model number YC5016, and the others are the same as those in Example 1.

[0048] Performance detection test The following is a performance test on the vehicle-mounted OCA prepared in Examples 1-5 and Comparative Examples 1-5, which is specifically as follows: 1. Ultraviolet light barrier rate test: Use an optical transmittance meter to test the ultraviolet light barrier rate (unit: %) of the vehicle-mounted OCA at a wavelength of 380 nm, and test and record the test results; 2. Aging resistance test: 1) Use a spectrophotometer to test the color values of the vehicle-mounted OCA before and after 1008 h of Q-SUN environmental testing respectively, and calculate the yellowing value (△b*), and test and calculate the test results; 2) Use a spectrophotometer to test the color values of the vehicle-mounted OCA before and after 1008 h of 95°C / 85% RH environmental testing respectively, and calculate the yellowing value (△b*), and test and calculate the test results; 3. Adhesion performance test: Refer to the test method in GB / T 7124-2008 to test the shear strength (unit: MPa) of the vehicle-mounted OCA, and test and record the test results; The following are the performance detection data of the vehicle-mounted OCA in Examples 1-5 and Comparative Examples 1-5, as specifically shown in Table 3 below.

[0049] Table 3 Performance data table of the vehicle-mounted OCA in Examples 1-5 and Comparative Examples 1-5 Combined with Examples 1-3 and Comparative Examples 1-5 and Table 3, it can be concluded that, compared with Example 1, in Comparative Example 1, the functionality of the polyurethane acrylate was changed, and the UV blocking rate, aging resistance and adhesion performance of the prepared vehicle-mounted OCA were reduced. This may be because the crosslinking density of the system was decreased. Compared with Example 1, in Comparative Example 2, the type and dosage of the silicone were changed, and the UV blocking rate, aging resistance and adhesion performance of the prepared vehicle-mounted OCA were reduced. This may be because the optimal ratio of the silicone segments was decreased, resulting in reduced heat resistance and UV resistance. Compared with Example 1, in Comparative Example 3, the type and functionality of the acrylate monomers were changed. Compared with Example 1, in Comparative Example 4, the type of the silane was changed. The UV blocking rate, aging resistance and adhesion performance of the prepared vehicle-mounted OCA were also reduced. In summary, it can be analyzed that when the silicone-modified polyurethane acrylate prepared by the present application is used, each component has a good synergistic effect.

[0050] Combined with Examples 1-3 and Examples 4-5 and Table 3, it can be concluded that further optimizing the type and ratio of the trifunctional acrylate monomers can further improve the performance of the prepared vehicle-mounted OCA. This may be because the trifunctional acrylate monomers with an optimal ratio have good crosslinking performance, which can further improve the macromolecular crosslinking structure of the prepared silicone-modified polyurethane acrylate, and thus the prepared vehicle-mounted OCA has excellent heat resistance, UV resistance and adhesion.

[0051] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment without creative contributions 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. An aging-resistant in-vehicle OCA, characterized in that, Prepared from the following raw materials in parts by weight: Organosilicon-modified polyurethane acrylate 70 - 90 parts Dilution monomer 15 - 25 parts Photoinitiator 3 - 8 parts Antioxidant 1 - 3 parts; The organosilicon-modified polyurethane acrylate is prepared from hexafunctional polyurethane acrylate, tetramethyltetravinylcyclotetrasiloxane, triisopropylsilyl methacrylate, trifunctional acrylate monomer, long-chain alkylsilane and catalyst.

2. The anti-aging vehicle-mounted OCA according to claim 1, characterized in that: The organosilicon-modified polyurethane acrylate is prepared from the following raw materials in parts by weight: Hexafunctional polyurethane acrylate 40 - 60 parts Tetramethyltetravinylcyclotetrasiloxane 4 - 6 parts Triisopropylsilyl methacrylate 5 - 8 parts Trifunctional acrylate monomer 10 - 15 parts Long-chain alkylsilane 2 - 4 parts Catalyst 0.2 - 0.4 part.

3. The anti-aging vehicle-mounted OCA according to claim 2, characterized in that: The trifunctional acrylate monomer is composed of pentaerythritol triacrylate and ethoxylated trimethylolpropane triacrylate in a weight ratio of 1:(2 - 4).

4. The anti-aging vehicle-mounted OCA according to claim 2, characterized in that: The long-chain alkylsilane is any one or combination of dodecyltrimethoxysilane, dodecyltriethoxysilane, hexadecyltrimethoxysilane.

5. The anti-aging vehicle-mounted OCA according to claim 1, characterized in that: The catalyst is benzoyl peroxide or diisopropylbenzene peroxide.

6. A weather-resistant vehicle-mounted OCA according to any one of claims 2-5, characterized in that: The organosilicon-modified polyurethane acrylate is prepared by the following steps: Add hexafunctional polyurethane acrylate, tetramethyltetravinylcyclotetrasiloxane, triisopropylsilyl methacrylate, trifunctional acrylate monomer, long-chain alkylsilane and catalyst into a reaction device, and react at a temperature of 70 - 80 °C for 1 - 2 h to obtain the organosilicon-modified polyurethane acrylate.

7. The aging-resistant vehicle-mounted OCA according to claim 1, characterized in that: The dilution monomer is composed of methyl methacrylate, lauryl methacrylate and glycidyl acrylate in a weight ratio of 1:(1 - 2):(1.5 - 2.5).

8. The anti-aging vehicle-mounted OCA according to claim 1, wherein: The photoinitiator is 1-hydroxycyclohexyl phenyl ketone and / or 2-hydroxy-2-methyl-1-phenyl-1-propanone, and the antioxidant is antioxidant 1010 and / or antioxidant 168.

9. A preparation method of an anti-aging vehicle-mounted OCA as described in any one of claims 1-8, characterized in that: Including the following steps: S1. Mix the organosilicon-modified polyurethane acrylate, dilution monomer, photoinitiator and antioxidant evenly, and perform vacuum degassing to obtain an adhesive; S2. Coat the adhesive on the surface of a release film, first perform ultraviolet curing, then perform thermal curing, and wind up to obtain an aging-resistant vehicle-mounted OCA.

10. The preparation method of an anti-aging vehicle-mounted OCA according to claim 9, characterized in that, The thickness of the vehicle-mounted OCA is 50 - 350 µm.

Images