Preparation method of organic silicon OCA optical adhesive

Abstract

The invention discloses a preparation method of an organic silicon OCA optical adhesive, and belongs to the technical field of screen protection films. The preparation method of the organic silicon OCA comprises the following steps: uniformly mixing an organic silicon pressure-sensitive adhesive, an inhibitor, a catalyst, a cross-linking agent and a solvent, and defoaming to obtain an organic silicon adhesive; and coating the organic silicon adhesive on the heavy release type protective film, curing, and adhering to the light release type protective film after curing to obtain the organic silicon OCA optical cement with the structure of the light release type protective film, the organic silicon adhesive layer and the heavy release type protective film from top to bottom. The organic silicon pressure-sensitive adhesive is combined with the cross-linking agent, so that the aging resistance of the optical adhesive can be effectively improved, and meanwhile, the bubble returning phenomenon is reduced. According to the invention, the organic silica gel layer is used as a main functional layer, and after coating and thermosetting in a wet coating manner, on the basis of ensuring complete curing of the adhesive layer, the obtained OCA optical adhesive has a relatively good anti-aging and anti-bubble effect, and has a wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of screen protection films, and in particular relates to a method for preparing an organic silicon OCA optical adhesive. Background Art

[0002] At present, the mobile phone market tends to be segmented and personalized. Full screen and curved screen have become the standard configuration of flagship models of mobile phone manufacturers. Due to the vigorous development of the mobile phone industry, the overall screen protection industry in the mobile phone after-sales market is also facing many demands and challenges. As the size of mobile phone screens becomes larger and larger, and the curvature of mobile phone screens becomes larger and larger, traditional double-sided tapes can no longer meet the requirements of large curved screen mobile phone screen protection. The mobile phone screen protection products on the market are widely used, including jelly glue, dot glue, high and low glue, UV water glue and silicone, among which jelly glue products are mainly aimed at large curved screen mobile phones. However, jelly glue products are prone to overflow during production and use, and the production process is complicated, the touch sensitivity and optics are poor, and the ultrasonic fingerprint unlocking is poor. However, the existing silicone products have poor adhesion to large curved surfaces and are not suitable for direct application in the screen protection of large curved screen mobile phones.

[0003] The patent application with publication number CN111154430A discloses a UV-curable OCA pressure-sensitive adhesive film and its preparation method. This type is made of acrylate adhesive. Since the CC bond energy of acrylic adhesive is lower than the Si-O bond energy of silicone, it has poor weather resistance in many scenarios, is easy to degrade and break, and turns yellow or cracks after aging, which cannot meet the current diversified applications. The patent application with publication number CN104004460A discloses a silicone gel optical adhesive film and its production process. This type uses a two-component thermosetting silicone adhesive. In the preparation of OCA film, due to the need to mix two components, the equipment investment is large, and it cannot be put into large-scale production. It is also easy to cause the adhesive liquid and gel to be scrapped, greatly affecting production efficiency.

[0004] In order to improve the performance of optical adhesives, the existing technology usually designs a more complex structure, which can easily lead to the light release film and the heavy release film being pulled apart during bonding, resulting in poor peeling effect. In addition, the existing OCA optical adhesives are generally produced by thermal curing. Due to the large thickness of the adhesive layer, there is often a problem of incomplete degassing in production. Many thermosetting adhesives are more prone to re-bubbling after being exposed to high temperatures for a long time. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing an organic silicon OCA optical adhesive to improve the anti-aging performance of the organic silicon OCA optical adhesive.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A method for preparing an organic silicon OCA optical adhesive comprises the following steps:

[0008] The organic silicone pressure-sensitive adhesive, inhibitor, catalyst, cross-linking agent and solvent are uniformly mixed and defoamed to obtain an organic silicone adhesive; the organic silicone adhesive is coated on a heavy release protective film, cured, and attached to a light release protective film after curing to obtain an organic silicone OCA optical adhesive having a structure of a light release protective film, an organic silicone adhesive layer and a heavy release protective film from top to bottom.

[0009] Among them, silicone pressure-sensitive adhesive generally refers to pressure-sensitive adhesive with silicone polymer as the main body, or acrylic and silicone modified rubber pressure-sensitive adhesive modified by silicone polymer. Compared with traditional acrylic pressure-sensitive adhesive and rubber pressure-sensitive adhesive, it has excellent chemical resistance, water resistance, oil resistance, solvent resistance, high temperature resistance, low temperature resistance, thermal degradation resistance, oxidation degradation resistance and other properties, and can be bonded with a variety of difficult-to-bond materials such as polyolefins (BOPP, PET, PE, etc.) without surface treatment, fluoroplastics, polyimides and polycarbonates. The cross-linking agent is also called a bridging agent, which forms a bridge bond between polymer molecular chains and becomes an insoluble substance with a three-dimensional structure. The solvent is a mixed compound of toluene, xylene, butanone, 100-200 solvent oil, etc., which evaporates after preparation.

[0010] Furthermore, the model of the silicone pressure-sensitive adhesive is 7695N.

[0011] Furthermore, the inhibitor is of the type I-112, I-114, I-116, I-200 or a combination of several of them.

[0012] Furthermore, the catalyst model is one or a combination of 4000, 4500, F50040, and F50050.

[0013] Furthermore, the cross-linking agent model is one of 7672, 7387, 7028, 8600 or a combination of several of them.

[0014] Furthermore, the solvent is one or a combination of toluene, xylene, butanone and 100-200 solvent oil.

[0015] Furthermore, the usage ratio of the organic silicone pressure-sensitive adhesive, the inhibitor, the catalyst, the cross-linking agent and the solvent is (20-80): (0.1-1): (0.01-1): (0.01-3): (20-80).

[0016] Furthermore, the usage ratio of the organic silicone pressure-sensitive adhesive, the inhibitor, the catalyst, the cross-linking agent and the solvent is (40-80): (0.1-1): (0.2-1): (0.2-2): (50-80).

[0017] Furthermore, the thickness of the organic silicone adhesive layer is 100-300 μm; the thickness of the light release protective film is 25-125 μm; and the thickness of the heavy release protective film is 50-150 μm.

[0018] Furthermore, the coating is performed by wet coating the heavy release film using a scraper.

[0019] Furthermore, the curing condition is curing at 135-145° C. for 5-15 min.

[0020] An organic silicon OCA optical adhesive is prepared by the above-mentioned organic silicon OCA optical adhesive preparation method.

[0021] Beneficial effects of the present invention:

[0022] (1) The organic silicone OCA optical adhesive provided by the present invention has an organic silicone layer as the main functional layer. The appropriate addition ratio is determined by testing the raw materials, and after heat curing by a precise coating method, the obtained OCA optical adhesive has a good anti-aging and anti-foaming effect while ensuring that the adhesive layer is completely cured.

[0023] (2) The organic silicone pressure-sensitive adhesive used in the present invention has good performance and can be bonded to a variety of difficult-to-bond materials; the cross-linking agent used forms bridge bonds between polymer molecular chains, turning them into insoluble substances with three-dimensional structures; the combination of the organic silicone pressure-sensitive adhesive and the cross-linking agent can effectively improve the aging resistance of the optical adhesive while reflecting its inherent characteristics and reducing the re-bubbling phenomenon.

[0024] (3) The present invention provides a method for preparing an organic silicone OCA optical adhesive, which has a simple preparation process, precise coating technology, and a high degree of curing of the product; the peeling effect is good and the adhesive is not easy to pull; the prepared optical adhesive is non-irritating to human skin and non-toxic. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below in conjunction with the accompanying drawings.

[0026] Figure 1 It is a schematic diagram of the structure of the organic silicon OCA optical adhesive of the present invention; DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Example 1

[0029] 60 parts of silicone pressure-sensitive adhesive 7695N, 0.5 parts of inhibitor I-112, 0.5 parts of catalyst 4000, 1.5 parts of cross-linking agent 7672 and 60 parts of toluene are mixed evenly and defoamed to obtain silicone adhesive; the silicone adhesive is wet-coated on the heavy release protective film with a scraper, and cured at 140°C for 10 minutes. After curing, it is attached to the light release protective film to obtain a silicone OCA optical adhesive with a structure of 75μm light release protective film, 200μm silicone adhesive layer and 100μm heavy release protective film from top to bottom.

[0030] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0031] Example 2

[0032] 80 parts of silicone pressure-sensitive adhesive 7695N, 1 part of inhibitor I-112, 1 part of catalyst 4000, 2 parts of cross-linking agent 7672 and 80 parts of toluene are mixed evenly and defoamed to obtain a silicone adhesive; the silicone adhesive is wet-coated on a heavy release protective film with a scraper, and cured at 140°C for 10 minutes. After curing, it is attached to a light release protective film to obtain a silicone OCA optical adhesive with a structure of a 75μm light release protective film, a 200μm silicone adhesive layer and a 100μm heavy release protective film from top to bottom.

[0033] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0034] Example 3

[0035] 20 parts of silicone pressure-sensitive adhesive 7695N, 0.1 parts of inhibitor I-112, 0.2 parts of catalyst 4000, 0.2 parts of cross-linking agent 7672 and 20 parts of toluene are mixed evenly and defoamed to obtain a silicone adhesive; the silicone adhesive is wet-coated on a heavy release protective film with a scraper, and cured at 140°C for 10 minutes. After curing, it is attached to a light release protective film to obtain a silicone OCA optical adhesive with a structure of a 75μm light release protective film, a 200μm silicone adhesive layer and a 100μm heavy release protective film from top to bottom.

[0036] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0037] Example 4

[0038] 60 parts of silicone pressure-sensitive adhesive 7695N, 0.5 parts of inhibitor I-112, 0.5 parts of catalyst 4000, 1.5 parts of cross-linking agent 7672 and 60 parts of toluene are mixed evenly and defoamed to obtain a silicone adhesive; the silicone adhesive is wet-coated on a heavy release protective film with a scraper, and cured at 135°C for 15 minutes. After curing, it is attached to a light release protective film to obtain a silicone OCA optical adhesive with a structure of a 75μm light release protective film, a 200μm silicone adhesive layer and a 100μm heavy release protective film from top to bottom.

[0039] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0040] Example 5

[0041] 60 parts of silicone pressure-sensitive adhesive 7695N, 0.5 parts of inhibitor I-112, 0.5 parts of catalyst 4000, 1.5 parts of cross-linking agent 7672 and 60 parts of toluene are mixed evenly and defoamed to obtain a silicone adhesive; the silicone adhesive is wet-coated on a heavy release protective film with a scraper, and cured at 145°C for 5 minutes. After curing, it is attached to a light release protective film to obtain a silicone OCA optical adhesive with a structure of a 75μm light release protective film, a 200μm silicone adhesive layer and a 100μm heavy release protective film from top to bottom.

[0042] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0043] Example 6

[0044] 60 parts of silicone pressure-sensitive adhesive 7695N, 0.5 parts of inhibitor I-112, 0.5 parts of catalyst 4000, 1.5 parts of cross-linking agent 7672 and 60 parts of toluene are mixed evenly and defoamed to obtain a silicone adhesive; the silicone adhesive is wet-coated on a heavy release protective film with a scraper, and cured at 140°C for 10 minutes. After curing, it is attached to a light release protective film to obtain a silicone OCA optical adhesive with a structure of a 125μm light release protective film, a 100μm silicone adhesive layer and a 150μm heavy release protective film from top to bottom.

[0045] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0046] Example 7

[0047] 60 parts of silicone pressure-sensitive adhesive 7695N, 0.5 parts of inhibitor I-112, 0.5 parts of catalyst 4000, 1.5 parts of cross-linking agent 7672 and 60 parts of toluene are mixed evenly and defoamed to obtain a silicone adhesive; the silicone adhesive is wet-coated on a heavy release protective film with a scraper, and cured at 140°C for 10 minutes. After curing, it is attached to a light release protective film to obtain a silicone OCA optical adhesive with a structure of a 25μm light release protective film, a 300μm silicone adhesive layer and a 50μm heavy release protective film from top to bottom.

[0048] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0049] Example 8

[0050] 60 parts of silicone pressure-sensitive adhesive 7695N, 0.5 parts of inhibitor I-114, 0.5 parts of catalyst 4500, 1.5 parts of cross-linking agent 7387 and 60 parts of xylene are mixed evenly and defoamed to obtain silicone adhesive; the silicone adhesive is wet-coated on the heavy release protective film with a scraper, and cured at 140°C for 10 minutes. After curing, it is attached to the light release protective film to obtain a silicone OCA optical adhesive with a structure of 75μm light release protective film, 200μm silicone adhesive layer and 100μm heavy release protective film from top to bottom.

[0051] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0052] Example 9

[0053] 60 parts of silicone pressure-sensitive adhesive 7695N, 0.5 parts of inhibitor I-200, 0.5 parts of catalyst F50050, 1.5 parts of cross-linking agent 8600 and 60 parts of butanone were mixed evenly and defoamed to obtain silicone adhesive; the silicone adhesive was wet-coated on the heavy release protective film with a scraper, and cured at 140°C for 10 minutes. After curing, it was attached to the light release protective film to obtain a silicone OCA optical adhesive with a structure of 75μm light release protective film, 200μm silicone adhesive layer and 100μm heavy release protective film from top to bottom.

[0054] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0055] Comparative Example 1

[0056] Compared with Example 1, this comparative example differs in that no crosslinking agent is added, and the specific implementation steps are as follows:

[0057] 60 parts of silicone pressure-sensitive adhesive 7695N, 0.5 parts of inhibitor I-112, 0.5 parts of catalyst 4000 and 60 parts of toluene are mixed evenly and defoamed to obtain a silicone adhesive; the silicone adhesive is wet-coated on a heavy release protective film with a scraper, and cured at 140°C for 10 minutes. After curing, it is attached to a light release protective film to obtain a silicone OCA optical adhesive with a structure of a 75μm light release protective film, a 200μm silicone adhesive layer and a 100μm heavy release protective film from top to bottom.

[0058] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0059] Comparative Example 2

[0060] Compared with Example 1, the difference between this comparative example and Example 1 is that the thickness of the organic silicone adhesive layer is 50 μm, and the specific implementation steps are as follows:

[0061] 60 parts of silicone pressure-sensitive adhesive 7695N, 0.5 parts of inhibitor I-112, 0.5 parts of catalyst 4000, 1.5 parts of cross-linking agent 7672 and 60 parts of toluene are mixed evenly and defoamed to obtain silicone adhesive; the silicone adhesive is wet-coated on the heavy release protective film with a scraper, and cured at 140°C for 10 minutes. After curing, it is attached to the light release protective film to obtain a silicone OCA optical adhesive with a structure of 75μm light release protective film, 50μm silicone adhesive layer and 100μm heavy release protective film from top to bottom.

[0062] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0063] Comparative Example 3

[0064] 60 parts of silicone pressure-sensitive adhesive 7695N, 2.5 parts of inhibitor I-112, 2.5 parts of catalyst 4000, 3 parts of cross-linking agent 7672 and 60 parts of toluene are mixed evenly and defoamed to obtain a silicone adhesive; the silicone adhesive is wet-coated on a heavy release protective film with a scraper, and cured at 140°C for 10 minutes. After curing, it is attached to a light release protective film to obtain a silicone OCA optical adhesive with a structure of a 75μm light release protective film, a 200μm silicone adhesive layer and a 100μm heavy release protective film from top to bottom.

[0065] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0066] Comparative Example 4

[0067] Compared with Example 1, the difference between this comparative example is that no cross-linking agent is added and the thickness of the organic silicone adhesive layer is reduced to 50 μm. The specific implementation steps are as follows:

[0068] 60 parts of silicone pressure-sensitive adhesive 7695N, 0.5 parts of inhibitor I-112, 0.5 parts of catalyst 4000 and 60 parts of toluene are mixed evenly and defoamed to obtain a silicone adhesive; the silicone adhesive is wet-coated on a heavy release protective film with a scraper, and cured at 140°C for 10 minutes. After curing, it is attached to a light release protective film to obtain a silicone OCA optical adhesive with a structure of a 75μm light release protective film, a 50μm silicone adhesive layer and a 100μm heavy release protective film from top to bottom.

[0069] The structure of the above-mentioned organic silicon OCA optical adhesive is as follows Figure 1 shown.

[0070] The anti-aging performance test was carried out on Examples 1 to 9 and Comparative Examples 1 to 4. The specific test method is as follows:

[0071] First tear off the light release film and laminate it to the glass, then tear off the heavy release film and laminate it to the polarizer. After lamination, pressurize and defoam (0.6MPa*30min), place at 95℃, and record whether there is anti-foaming at 0h, 500h and 1000h respectively;

[0072] The results are shown in Table 1:

[0073] Table 1

[0074]

[0075]

[0076] From the examples, comparative examples and Table 1, it can be seen that compared with Example 1, Examples 2-3 differ in that the raw material components are changed within a reasonable range, compared with Example 1, Examples 4-5 differ only in the curing conditions, compared with Example 1, Examples 6-7 differ in the thickness changes of the light release protective film, the silicone adhesive layer and the heavy release protective film, and compared with Example 1, Examples 8-9 differ in the reasonable replacement of raw materials. The results show that the silicone OCA optical adhesive prepared by the present invention is kept at 95°C for 1000 hours without rebubbling, and has good anti-aging effect.

[0077] Comparing Comparative Examples 1-4 with Example 1, it was found that after no cross-linking agent was added in Comparative Example 1, the optical adhesive produced bubbling. This is because the cross-linking agent can form bridge bonds between polymer molecular chains and become an insoluble substance with a three-dimensional structure, thereby improving the anti-aging performance of the optical adhesive; Comparative Example 2 also showed slight bubbling after reducing the thickness of the organic silicone adhesive layer. The thickness ratio between the organic silicone adhesive layer and the protective film was too small, resulting in a decrease in the performance of the optical adhesive; Compared with Example 1, in Comparative Example 3, excessive addition of additives such as cross-linking agents will lead to poor compatibility between materials, thereby resulting in a decrease in the performance of the optical adhesive; In Comparative Example 4, more bubbles appeared after reducing the thickness of the organic silicone adhesive layer without adding a cross-linking agent.

[0078] In summary, the organic silicone OCA optical adhesive prepared by the method for preparing an organic silicone OCA optical adhesive provided by the present invention has a high degree of curing, good peeling effect, strong aging resistance, and broad application prospects.

[0079] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

[0080] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing an organic silicon OCA optical adhesive, characterized in that: The steps include: The organic silicone pressure-sensitive adhesive, inhibitor, catalyst, cross-linking agent and solvent are uniformly mixed and defoamed to obtain an organic silicone adhesive; the organic silicone adhesive is coated on a heavy release protective film, cured, and attached to a light release protective film after curing to obtain an organic silicone OCA optical adhesive having a structure of a light release protective film, an organic silicone adhesive layer and a heavy release protective film from top to bottom.

2. The method for preparing an organic silicon OCA optical adhesive according to claim 1, characterized in that: The model of the organic silicone pressure-sensitive adhesive is 7695N.

3. The method for preparing an organic silicon OCA optical adhesive according to claim 1, characterized in that: The inhibitor is of the type I-112, I-114, I-116, I-200 or a combination of several of them.

4. The method for preparing an organic silicon OCA optical adhesive according to claim 1, characterized in that: The catalyst model is one of 4000, 4500, F50040, F50050 or a combination of several of them.

5. The method for preparing an organic silicon OCA optical adhesive according to claim 1, characterized in that: The cross-linking agent model is one of 7672, 7387, 7028, 8600 or a combination of several of them.

6. The method for preparing an organic silicon OCA optical adhesive according to claim 1, characterized in that: The solvent is one or a combination of toluene, xylene, butanone and 100-200 solvent oil.

7. The method for preparing an organic silicon OCA optical adhesive according to claim 1, characterized in that: The usage ratio of the organic silicon pressure-sensitive adhesive, the inhibitor, the catalyst, the cross-linking agent and the solvent is (20-80): (0.1-1): (0.1-1): (0.1-2): (20-80).

8. The method for preparing an organic silicon OCA optical adhesive according to claim 1, characterized in that: The thickness of the organic silicone adhesive layer is 100-300 μm; the thickness of the light release protective film is 25-125 μm; and the thickness of the heavy release protective film is 50-150 μm.

9. The method for preparing an organic silicon OCA optical adhesive according to claim 1, characterized in that: The curing condition is curing at 135-145° C. for 5-15 minutes; and the coating is wet coating of the heavy release film using a scraper.

10. An organic silicon OCA optical adhesive, characterized in that: The organic silicon OCA optical adhesive is prepared according to the preparation method of any one of claims 1 to 9.

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