OCA (Optical Clear Adhesive) and production process thereof

Abstract

The invention discloses an OCA optical adhesive and a production process thereof. The OCA optical adhesive is prepared from the following raw materials in parts by weight: 70 to 80 parts of 2-ethylhexyl acrylate, 20 to 30 parts of methyl methacrylate, 10 to 15 parts of hydroxyethyl acrylate, 7 to 8 parts of acrylic acid, 8 to 10 parts of modified monomer, 1 to 1.5 parts of modified filler, 2 to 3 parts of 2-hydroxy-2-methyl-1-phenyl-1-acetone and 8 to 10 parts of tetrahydrofuran. Double bonds on the modified monomer and double bonds on the surface of the modified filler can react with other monomers in the raw materials, the modified monomer is of a dendritic structure, OCA optical cement molecules can form the dendritic structure, and the modified filler can form a structure that an organic polymer chain is wrapped by an inorganic matter. And through cooperation with an imine structure on the modified monomer, a boric acid ester structure and an imine structure on the modified filler, the prepared OCA optical cement has a very good bending-resistant effect.

Description

Technical Field

[0001] The present invention relates to the technical field of optical adhesive preparation, and particularly relates to an OCA optical adhesive and its production process. Background Art

[0002] In the current technological era, with the continuous increase in people's demand for portable devices, foldable mobile phones and smart wearable devices have gradually become market hotspots. These devices widely use foldable display screens, and to achieve this goal, the key lies in using bend-resistant materials to connect the display screens to avoid damage during the bending process. OCA optical adhesive is one of such key materials. The OCA optical adhesive tightly bonds two laminated optical surfaces together. Its unique feature is that it can withstand a certain degree of bending and twisting while maintaining good optical performance. In the prior art, OCA optical adhesives are used in many electronic products, especially playing an indispensable role in the production of foldable devices. However, for the requirements of foldable screens, traditional OCA optical adhesives are prone to performance degradation during repeated folding, such as uneven adhesion, optical performance deviation, etc. These problems limit the wide application and development speed of foldable screen devices. Summary of the Invention

[0003] The purpose of the present invention is to provide an OCA optical adhesive and its production process, which solves the problem that the OCA optical adhesive has poor bend resistance and is prone to delamination after multiple uses in foldable mobile phones at the present stage.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A production process of an OCA optical adhesive specifically includes the following steps:

[0006] Step A1: Disperse wollastonite in ethanol, stir and add KH550 and deionized water under the conditions of a rotation speed of 200 - 300 r / min and a temperature of 60 - 70 °C, react for 3 - 5 h to obtain pretreated wollastonite. Mix the pretreated wollastonite, tetra-(4-formylphenyl)ethylene, and ethanol evenly, and under the conditions of a rotation speed of 150 - 200 r / min, a temperature of 70 - 80 °C, and a pH value of 8 - 8.5, carry out a reflux reaction for 2 - 3 h, filter to remove the filtrate, and dry the substrate to obtain a modified filler;

[0007] Step A2: Weigh the following raw materials in parts by weight: 70 - 80 parts of 2-ethylhexyl acrylate, 20 - 30 parts of methyl methacrylate, 10 - 15 parts of hydroxyethyl acrylate, 7 - 8 parts of acrylic acid, 8 - 10 parts of a modified monomer, 1 - 1.5 parts of a modified filler, 2 - 3 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 8 - 10 parts of tetrahydrofuran. Mix the raw materials evenly to obtain the OCA optical adhesive.

[0008] Further, the dosage ratio of KH550 described in step A1 is 2% of the mass of wollastonite, and the mass ratio of the pretreated wollastonite to tetrakis(4-formylphenyl)ethylene is 1:1.

[0009] Further, the modified monomer is prepared by the following steps:

[0010] Step B1: Mix p-nitrostyrene, trichlorosilane, chloroplatinic acid and DMF evenly, introduce nitrogen protection, and react for 3 - 5 h under the conditions of a rotation speed of 150 - 200 r / min and a temperature of 70 - 80 °C to obtain intermediate 1. Mix lithium dimethylvinylsilanolate and tetrahydrofuran, introduce nitrogen protection, stir and add hexamethylcyclotrisiloxane under the conditions of a rotation speed of 120 - 150 r / min and a temperature of 25 - 30 °C, react for 6 - 8 h, and then add intermediate 1 and continue to react for 1 - 1.5 h to obtain the pretreated polysiloxane;

[0011] Step B2: Mix the pretreated polysiloxane, palladium-carbon catalyst and DMF evenly, introduce hydrogen until the pressure is 0.3 - 0.5 MPa, and react for 4 - 5 h under the conditions of a rotation speed of 60 - 80 r / min and a temperature of 80 - 85 °C to obtain the modified polysiloxane. Mix diethanolamine, acrylic acid, dicyclohexylcarbodiimide and tetrahydrofuran, and react for 3 - 5 h under the conditions of a rotation speed of 200 - 300 r / min and a temperature of 30 - 35 °C to obtain intermediate 2;

[0012] Step B3: Mix 4-formylphenylboronic acid, intermediate 2 and DMF evenly, introduce nitrogen protection, and react for 1 - 2 h under the conditions of a rotation speed of 200 - 300 r / min and a temperature of 50 - 60 °C to obtain intermediate 3. Mix intermediate 3, modifier, chloroplatinic acid and DMF, introduce nitrogen protection, react for 6 - 8 h under the conditions of a rotation speed of 150 - 200 r / min and a temperature of 70 - 80 °C, then add the modified polysiloxane, raise the temperature to 100 - 110 °C, and continue to react for 3 - 5 h to obtain the modified monomer.

[0013] Further, the molar ratio of p-nitrostyrene to trichlorosilane described in step B1 is 1:1, the dosage of chloroplatinic acid is 1‰ of the mass of trichlorosilane, and the molar ratio of lithium dimethylvinylsilanolate, hexamethylcyclotrisiloxane and intermediate 1 is 2:8:1.

[0014] Further, the dosage of the palladium-carbon catalyst described in step B2 is 5% of the mass of the pretreated polysiloxane, and the molar ratio of diethanolamine, acrylic acid and dicyclohexylcarbodiimide is 1:1:1.1.

[0015] Further, the molar ratio of 4-formylphenylboronic acid to intermediate 2 described in step B3 is 1:1, the molar ratio of intermediate 3, Si-H bond on the modifier and modified polysiloxane is 1:1:1, and the dosage of chloroplatinic acid is 1‰ of the mass of the modifier.

[0016] Further, the modifier is prepared by the following steps:

[0017] Mix diphenyldimethoxysilane, octamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane, hexamethyldisiloxane, tetramethylammonium hydroxide and deionized water, introduce nitrogen protection, and react at a rotation speed of 200 - 300 r / min and a temperature of 90 - 95 °C for 10 - 15 h, then raise the temperature to 105 - 110 °C and react for 2 - 3 h, then raise the temperature to 150 - 160 °C and keep warm for 30 - 40 min to obtain the modifier.

[0018] Further, the dosage ratio of diphenyldimethoxysilane, octamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane, hexamethyldisiloxane, tetramethylammonium hydroxide and deionized water is 0.2 mol:1.7 mol:0.5 mol:1 mol:2 mol:40 mL.

[0019] The beneficial effects of the present invention: An OCA optical adhesive disclosed in this application comprises the following raw materials: 2-ethylhexyl acrylate, methyl methacrylate, 2-hydroxyethyl acrylate, acrylic acid, modified monomer, modified filler, 2-hydroxy-2-methyl-1-phenyl-1-propanone and tetrahydrofuran. The modified filler is prepared by treating wollastonite with KH550 as the raw material to pretreat the surface of wollastonite, and reacting the pretreated wollastonite with tetra-(4-formylphenyl)ethylene to make the aldehyde groups on the pretreated wollastonite and tetra-(4-formylphenyl)ethylene react to form imine, thus obtaining the modified filler.

[0020] The modified monomer is prepared by reacting p-nitrostyrene with trichlorosilane to make the double bond on p-nitrostyrene react with the Si-H bond on trichlorosilane to obtain intermediate 1. Using lithium dimethylvinylsilanolate as an initiator, hexamethylcyclotrisiloxane as a polymerization monomer for ring-opening polymerization, and then blocking with intermediate 1 to obtain pretreated polysiloxane. The pretreated polysiloxane is reduced with palladium-carbon catalyst to convert the nitro group on the pretreated polysiloxane into an amino group to obtain modified polysiloxane. Diethanolamine reacts with acrylic acid to make the secondary amine on diethanolamine and the carboxyl group on acrylic acid undergo dehydration reaction to obtain intermediate 2. Intermediate 2 reacts with 4-formylphenylboronic acid to make the hydroxyl group on intermediate 2 react with the boronic acid group on 4-formylphenylboronic acid to form borate ester to obtain intermediate 3. Intermediate 3 reacts with the modifier to make the double bond on intermediate 3 react with the Si-H bond on the modifier, and then is blended with the modified polysiloxane to make the aldehyde group on intermediate 3 react with the amino group on the modified polysiloxane to form imine, thus obtaining the modified monomer.

[0021] The modifier is prepared by reacting diphenyldimethoxysilane, octamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane and hexamethyldisiloxane, hydrolyzing diphenyldimethoxysilane, then undergoing ring-opening reaction with octamethylcyclotetrasiloxane and hexamethylcyclotetrasiloxane, and finally end-capping with hexamethyldisiloxane.

[0022] When the raw material blend is irradiated with ultraviolet light, the double bonds on the modified monomer and the double bonds on the surface of the modified filler can react with other monomers in the raw material. The modified monomer has a dendritic structure, and thus can form a dendritic structure of the OCA optical adhesive molecules. At the same time, the modified filler can form a structure in which inorganic substances sandwich organic polymer chains, which cooperate with the imine structure and borate ester structure on the modified monomer and the imine structure on the modified filler, so that the prepared OCA optical adhesive has good bending resistance, can relieve the interlayer shear stress, and reduce the risk of delamination between the OVA optical adhesive layer and the screen. Specific embodiments

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0024] Embodiment 1, a production process of an OCA optical adhesive, specifically including the following steps:

[0025] Step A1: Disperse wollastonite in ethanol, stir and add KH550 and deionized water at a rotation speed of 200 r / min and a temperature of 60 °C, and react for 3 h to obtain pretreated wollastonite. Mix the pretreated wollastonite, tetrakis(4-formylphenyl)ethylene and ethanol evenly, and carry out reflux reaction at a rotation speed of 150 r / min, a temperature of 70 °C and a pH value of 8 for 2 h. Filter to remove the filtrate, and dry the substrate to obtain a modified filler.

[0026] Step A2: Weigh the following raw materials in parts by weight: 70 parts of 2-ethylhexyl acrylate, 20 parts of methyl methacrylate, 10 parts of hydroxyethyl acrylate, 7 parts of acrylic acid, 8 parts of modified monomer, 1 part of modified filler, 2 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone and 8 parts of tetrahydrofuran. Mix the raw materials evenly to obtain an OCA optical adhesive.

[0027] The dosage ratio of KH550 in Step A1 is 2% of the mass of wollastonite, and the mass ratio of pretreated wollastonite to tetrakis(4-formylphenyl)ethylene is 1:1.

[0028] The modified monomer is prepared by the following steps:

[0029] Step B1: Mix p-nitrostyrene, trichlorosilane, chloroplatinic acid, and DMF evenly, introduce nitrogen for protection, and react for 3 h under the conditions of a rotation speed of 150 r / min and a temperature of 70 °C to obtain Intermediate 1. Mix lithium dimethylvinylsilanolate and tetrahydrofuran, introduce nitrogen for protection, stir and add hexamethylcyclotrisiloxane under the conditions of a rotation speed of 120 r / min and a temperature of 25 °C, react for 6 h, then add Intermediate 1 and continue to react for 1 h to obtain pretreated polysiloxane;

[0030] Step B2: Mix the pretreated polysiloxane, palladium-carbon catalyst, and DMF evenly, introduce hydrogen until the pressure reaches 0.3 MPa, and react for 4 h under the conditions of a rotation speed of 60 r / min and a temperature of 80 °C to obtain modified polysiloxane. Mix diethanolamine, acrylic acid, dicyclohexylcarbodiimide, and tetrahydrofuran, and react for 3 h under the conditions of a rotation speed of 200 r / min and a temperature of 30 °C to obtain Intermediate 2;

[0031] Step B3: Mix 4-formylphenylboronic acid, Intermediate 2, and DMF evenly, introduce nitrogen for protection, and react for 1 h under the conditions of a rotation speed of 200 r / min and a temperature of 50 °C to obtain Intermediate 3. Mix Intermediate 3, modifier, chloroplatinic acid, and DMF, introduce nitrogen for protection, react for 6 h under the conditions of a rotation speed of 150 r / min and a temperature of 70 °C, then add the modified polysiloxane, raise the temperature to 100 °C, and continue to react for 3 h to obtain the modified monomer.

[0032] In Step B1, the molar ratio of p-nitrostyrene to trichlorosilane is 1:1, the dosage of chloroplatinic acid is 1‰ of the mass of trichlorosilane, and the molar ratio of lithium dimethylvinylsilanolate, hexamethylcyclotrisiloxane, and Intermediate 1 is 2:8:1.

[0033] In Step B2, the dosage of the palladium-carbon catalyst is 5% of the mass of the pretreated polysiloxane, and the molar ratio of diethanolamine, acrylic acid, and dicyclohexylcarbodiimide is 1:1:1.1.

[0034] In Step B3, the molar ratio of 4-formylphenylboronic acid to Intermediate 2 is 1:1, the molar ratio of Intermediate 3, the Si-H bond on the modifier, and the modified polysiloxane is 1:1:1, and the dosage of chloroplatinic acid is 1‰ of the mass of the modifier.

[0035] The modifier is prepared by the following steps:

[0036] Mix diphenyldimethoxysilane, octamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane, hexamethyldisiloxane, tetramethylammonium hydroxide and deionized water, and introduce nitrogen for protection. React for 10 h under the conditions of a rotation speed of 200 r / min and a temperature of 90 °C, then raise the temperature to 105 °C and react for 2 h, and then raise the temperature to 150 °C and keep warm for 30 min to obtain the modifier.

[0037] The dosage ratios of the diphenyldimethoxysilane, octamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane, hexamethyldisiloxane, tetramethylammonium hydroxide and deionized water are 0.2 mol: 1.7 mol: 0.5 mol: 1 mol: 2 mol: 40 mL.

[0038] Example 2, a production process of OCA optical adhesive, specifically includes the following steps:

[0039] Step A1: Disperse wollastonite in ethanol, stir and add KH550 and deionized water under the conditions of a rotation speed of 200 r / min and a temperature of 65 °C, react for 4 h to obtain pretreated wollastonite, mix the pretreated wollastonite, tetrakis(4-formylphenyl)ethylene and ethanol evenly, and reflux and react for 3 h under the conditions of a rotation speed of 150 r / min, a temperature of 75 °C and a pH value of 8, filter to remove the filtrate, and dry the substrate to obtain the modified filler.

[0040] Step A2: Weigh the following raw materials in parts by weight: 75 parts of 2-ethylhexyl acrylate, 25 parts of methyl methacrylate, 13 parts of hydroxyethyl acrylate, 7.5 parts of acrylic acid, 9 parts of modified monomer, 1.3 parts of modified filler, 2.5 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone and 9 parts of tetrahydrofuran, mix the raw materials evenly to obtain the OCA optical adhesive.

[0041] The dosage ratio of KH550 in Step A1 is 2% of the mass of wollastonite, and the mass ratio of pretreated wollastonite to tetrakis(4-formylphenyl)ethylene is 1:1.

[0042] The modified monomer is prepared by the following steps:

[0043] Step B1: Mix p-nitrostyrene, trichlorosilane, chloroplatinic acid and DMF evenly, introduce nitrogen for protection, and react for 4 h under the conditions of a rotation speed of 150 r / min and a temperature of 75 °C to obtain Intermediate 1. Mix lithium dimethylethenylsilanolate and tetrahydrofuran, introduce nitrogen for protection, stir and add hexamethylcyclotrisiloxane under the conditions of a rotation speed of 150 r / min and a temperature of 25 °C, react for 7 h, then add Intermediate 1 and continue to react for 1.5 h to obtain the pretreated polysiloxane.

[0044] Step B2: Mix the pretreated polysiloxane, palladium-carbon catalyst, and DMF evenly, introduce hydrogen until the pressure reaches 0.4 MPa, and react for 4 h under the conditions of a rotation speed of 60 r / min and a temperature of 80 °C to obtain the modified polysiloxane. Mix diethanolamine, acrylic acid, dicyclohexylcarbodiimide, and tetrahydrofuran, and react for 4 h under the conditions of a rotation speed of 300 r / min and a temperature of 30 °C to obtain Intermediate 2;

[0045] Step B3: Mix 4-formylphenylboronic acid, Intermediate 2, and DMF evenly, introduce nitrogen for protection, and react for 2 h under the conditions of a rotation speed of 200 r / min and a temperature of 55 °C to obtain Intermediate 3. Mix Intermediate 3, modifier, chloroplatinic acid, and DMF, introduce nitrogen for protection, react for 7 h under the conditions of a rotation speed of 150 r / min and a temperature of 75 °C, then add the modified polysiloxane, raise the temperature to 105 °C, and continue to react for 4 h to obtain the modified monomer.

[0046] In Step B1, the molar ratio of p-nitrostyrene to trichlorosilane is 1:1, the dosage of chloroplatinic acid is 1‰ of the mass of trichlorosilane, and the molar ratio of lithium dimethylvinylsilanolate, hexamethylcyclotrisiloxane, and Intermediate 1 is 2:8:1.

[0047] In Step B2, the dosage of the palladium-carbon catalyst is 5% of the mass of the pretreated polysiloxane, and the molar ratio of diethanolamine, acrylic acid, and dicyclohexylcarbodiimide is 1:1:1.1.

[0048] In Step B3, the molar ratio of 4-formylphenylboronic acid to Intermediate 2 is 1:1, the molar ratio of the Si-H bond on Intermediate 3, modifier, and the modified polysiloxane is 1:1:1, and the dosage of chloroplatinic acid is 1‰ of the mass of the modifier.

[0049] The modifier is prepared by the following steps:

[0050] Mix diphenyldimethoxysilane, octamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane, hexamethyldisiloxane, tetramethylammonium hydroxide, and deionized water, introduce nitrogen for protection, react for 13 h under the conditions of a rotation speed of 200 r / min and a temperature of 95 °C, then raise the temperature to 105 °C and react for 3 h, and then raise the temperature to 155 °C and keep it warm for 35 min to obtain the modifier.

[0051] The dosage ratio of diphenyldimethoxysilane, octamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane, hexamethyldisiloxane, tetramethylammonium hydroxide, and deionized water is 0.2 mol:1.7 mol:0.5 mol:1 mol:2 mol:40 mL.

[0052] Example 3, a production process of OCA optical adhesive, specifically includes the following steps:

[0053] Step A1: Disperse wollastonite in ethanol. Under the conditions of a rotation speed of 300 r / min and a temperature of 70 °C, stir and add KH550 and deionized water, and react for 5 h to obtain pretreated wollastonite. Mix the pretreated wollastonite, tetra-(4-formylphenyl)ethylene, and ethanol evenly. Under the conditions of a rotation speed of 200 r / min, a temperature of 80 °C, and a pH value of 8.5, carry out reflux reaction for 3 h, filter to remove the filtrate, and dry the substrate to obtain a modified filler.

[0054] Step A2: Weigh the following raw materials in parts by weight: 80 parts of 2-ethylhexyl acrylate, 30 parts of methyl methacrylate, 15 parts of hydroxyethyl acrylate, 8 parts of acrylic acid, 10 parts of a modified monomer, 1.5 parts of the modified filler, 3 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 10 parts of tetrahydrofuran. Mix the raw materials evenly to obtain an OCA optical adhesive.

[0055] The dosage ratio of KH550 described in Step A1 is 2% of the mass of wollastonite, and the mass ratio of pretreated wollastonite to tetra-(4-formylphenyl)ethylene is 1:1.

[0056] The described modified monomer is prepared by the following steps:

[0057] Step B1: Mix p-nitrostyrene, trichlorosilane, chloroplatinic acid, and DMF evenly, introduce nitrogen protection, and under the conditions of a rotation speed of 200 r / min and a temperature of 80 °C, react for 5 h to obtain Intermediate 1. Mix lithium dimethylvinylsilanolate and tetrahydrofuran, introduce nitrogen protection, and under the conditions of a rotation speed of 150 r / min and a temperature of 30 °C, stir and add hexamethylcyclotrisiloxane, react for 8 h, then add Intermediate 1, and continue to react for 1.5 h to obtain pretreated polysiloxane.

[0058] Step B2: Mix the pretreated polysiloxane, palladium-carbon catalyst, and DMF evenly, introduce hydrogen until the pressure reaches 0.5 MPa, and under the conditions of a rotation speed of 80 r / min and a temperature of 85 °C, react for 5 h to obtain modified polysiloxane. Mix diethanolamine, acrylic acid, dicyclohexylcarbodiimide, and tetrahydrofuran, and under the conditions of a rotation speed of 300 r / min and a temperature of 35 °C, react for 5 h to obtain Intermediate 2.

[0059] Step B3: Mix 4-formylphenylboronic acid, Intermediate 2, and DMF evenly, introduce nitrogen for protection, and react for 2 h under the conditions of a rotation speed of 300 r / min and a temperature of 60 °C to obtain Intermediate 3. Mix Intermediate 3, the modifier, chloroplatinic acid, and DMF, introduce nitrogen for protection, react for 8 h under the conditions of a rotation speed of 200 r / min and a temperature of 80 °C, then add the modified polysiloxane, raise the temperature to 110 °C, and continue to react for 5 h to obtain the modified monomer.

[0060] In Step B1, the molar ratio of p-nitrostyrene to trichlorosilane is 1:1, the dosage of chloroplatinic acid is 1‰ of the mass of trichlorosilane, and the molar ratio of lithium dimethylethenylsilanolate, hexamethylcyclotrisiloxane, and Intermediate 1 is 2:8:1.

[0061] In Step B2, the dosage of the palladium-carbon catalyst is 5% of the mass of the pretreated polysiloxane, and the molar ratio of diethanolamine, acrylic acid, and dicyclohexylcarbodiimide is 1:1:1.1.

[0062] In Step B3, the molar ratio of 4-formylphenylboronic acid to Intermediate 2 is 1:1, the molar ratio of Intermediate 3, the Si-H bond on the modifier, and the modified polysiloxane is 1:1:1, and the dosage of chloroplatinic acid is 1‰ of the mass of the modifier.

[0063] The modifier is prepared by the following steps:

[0064] Mix diphenyldimethoxysilane, octamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane, hexamethyldisiloxane, tetramethylammonium hydroxide, and deionized water, introduce nitrogen for protection, react for 15 h under the conditions of a rotation speed of 300 r / min and a temperature of 95 °C, then raise the temperature to 110 °C and react for 3 h, then raise the temperature to 160 °C and keep it warm for 40 min to obtain the modifier.

[0065] The dosage ratio of diphenyldimethoxysilane, octamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane, hexamethyldisiloxane, tetramethylammonium hydroxide, and deionized water is 0.2 mol:1.7 mol:0.5 mol:1 mol:2 mol:40 mL.

[0066] Comparative Example 1: In this comparative example, wollastonite is used instead of the modified filler compared with Example 1, and the remaining steps are the same.

[0067] Comparative Example 2: In this comparative example, wollastonite is dispersed in ethanol, stirred and KH570 and deionized water are added under the conditions of a rotation speed of 200 r / min and a temperature of 60 °C, and the reaction is carried out for 3 h. The obtained product is used instead of the modified filler, and the remaining steps are the same.

[0068] Comparative Example 3: Compared with Example 1, in this comparative example, the modified polysiloxane, modified polysiloxane and DMF were mixed and reacted for 3 h under the conditions of a rotation speed of 150 r / min and a temperature of 100 °C. The obtained product was used to replace the modified monomer, and the remaining steps were the same.

[0069] Comparative Example 4: Compared with Example 1, in this comparative example, phenyl dimethoxysilane was not added, and the remaining steps were the same.

[0070] The initial tack of the OCA optical adhesives prepared in Examples 1-3 and Comparative Examples 1-4 was detected according to the standard of GB / T4852-2002, the holding tack was detected according to the standard of GB / T4851-2014, and the 180° peel strength was detected according to the standard of GB / T2792-2014. A dynamic bending test was carried out at a bending radius of 5 mm, a frequency of 40 times / min, and 100,000 bends. The situation of the adhesive film was observed, and the test results are shown in Table 1 below.

[0071] Table 1

[0072]

[0073] It can be seen from Table 1 that the present application has good adhesiveness and good bending resistance.

[0074] The above content is only an example and explanation of the concept of the present invention. Those skilled in the art of this technology can make various modifications or supplements to the described specific embodiments or use similar methods to replace them. As long as they do not deviate from the concept of the invention or exceed the scope defined by this claim book, they should all fall within the protection scope of the present invention.

Claims

1. A production process of OCA optical adhesive, characterized in that: Specifically, it includes the following steps: Step A1: Disperse wollastonite in ethanol, stir and add KH550 and deionized water, react for 3 - 5 h to obtain pretreated wollastonite. Mix the pretreated wollastonite, tetra-(4-formylphenyl)ethylene and ethanol, reflux and react, filter to remove the filtrate, and dry the substrate to obtain a modified filler; Step A2: Weigh the following raw materials in parts by weight: 70 - 80 parts of 2-ethylhexyl acrylate, 20 - 30 parts of methyl methacrylate, 10 - 15 parts of hydroxyethyl acrylate, 7 - 8 parts of acrylic acid, 8 - 10 parts of modified monomer, 1 - 1.5 parts of modified filler, 2 - 3 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone, and 8 - 10 parts of tetrahydrofuran. Mix the raw materials evenly to obtain an OCA optical adhesive.

2. The production process of an OCA optical adhesive according to claim 1, characterized in that: The dosage ratio of KH550 described in Step A1 is 2% of the mass of wollastonite, and the mass ratio of pretreated wollastonite to tetra-(4-formylphenyl)ethylene is 1:

1.

3. The production process of an OCA optical adhesive according to claim 1, characterized in that: The modified monomer is prepared by the following steps: Step B1: Mix p-nitrostyrene, trichlorosilane, chloroplatinic acid and DMF evenly, introduce nitrogen protection, and react to obtain Intermediate 1. Mix lithium dimethylvinylsilanolate and tetrahydrofuran, introduce nitrogen protection, stir and add hexamethylcyclotrisiloxane, react, and then add Intermediate 1 and continue to react to obtain pretreated polysiloxane; Step B2: Mix the pretreated polysiloxane, palladium-carbon catalyst and DMF evenly, introduce hydrogen, and react to obtain modified polysiloxane. Mix diethanolamine, acrylic acid, dicyclohexylcarbodiimide and tetrahydrofuran and react to obtain Intermediate 2; Step B3: Mix 4-formylphenylboronic acid, Intermediate 2 and DMF evenly, introduce nitrogen protection, and react to obtain Intermediate 3. Mix Intermediate 3, modifier, chloroplatinic acid and DMF, introduce nitrogen protection, react, add modified polysiloxane, and raise the temperature to continue reacting to obtain the modified monomer.

4. The production process of an OCA optical adhesive according to claim 3, characterized in that: The molar ratio of p-nitrostyrene to trichlorosilane described in Step B1 is 1:1, and the molar ratio of lithium dimethylvinylsilanolate, hexamethylcyclotrisiloxane and Intermediate 1 is 2:8:

1.

5. The production process of an OCA optical adhesive according to claim 3, characterized in that: The dosage of the palladium-carbon catalyst described in Step B2 is 5% of the mass of pretreated polysiloxane, and the molar ratio of diethanolamine, acrylic acid and dicyclohexylcarbodiimide is 1:1:1.

1.

6. The production process of an OCA optical adhesive according to claim 3, characterized in that: The molar ratio of 4-formylphenylboronic acid to Intermediate 2 described in Step B3 is 1:1, and the molar ratio of Intermediate 3, Si-H bond on the modifier and modified polysiloxane is 1:1:

1.

7. The production process of an OCA optical adhesive according to claim 3, characterized in that: The modifier is prepared by the following steps: Mix diphenyldimethoxysilane, octamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane, hexamethyldisiloxane, tetramethylammonium hydroxide and deionized water, introduce nitrogen protection, and react to obtain the modifier.

8. The production process of an OCA optical adhesive according to claim 7, characterized in that: The dosage ratio of diphenyldimethoxysilane, octamethylcyclotetrasiloxane, hexamethylcyclotetrasiloxane, hexamethyldisiloxane, tetramethylammonium hydroxide and deionized water is 0.2 mol:1.7 mol:0.5 mol:1 mol:2 mol:40 mL.

9. An OCA optical adhesive, characterized in that: Produced by any one of the production methods according to Claims 1 - 8.

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