A tackifier and preparation method thereof and organic silicon optical adhesive

Abstract

The present invention provides a tackifier, a preparation method thereof and an organic silicon optical adhesive. The tackifier comprises at least one of the polymers of formula I and formula III; the preparation method comprises the following steps: mixing a difunctional acryloxysiloxane, a difunctional vinylsiloxane, a difunctional alkylsiloxane and an acid catalyst, reacting to obtain a mixture; adding a trifunctional siloxane, a vinyl end-capping agent and a base catalyst to the above reaction system, reacting to obtain a prepolymer; adding trisiloxane hydrogen siloxane and a platinum catalyst to the prepolymer reaction system, reacting to obtain the tackifier. The present invention designs the composition of the tackifier and the structure of the polymer of formula I and III, and further designs that the polymer of formula I and III contains acryloxy and alkoxy, thereby preparing a tackifier with excellent performance, and the organic silicon optical adhesive prepared by the tackifier has high bonding force and high optical performance.

Description

Technical Field

[0001] The invention belongs to the technical field of tackifier materials, and in particular relates to a tackifier and a preparation method thereof, and an organic silicon optical adhesive. Background Art

[0002] OCA (Optical Clear Adhesive) refers to a solid double-sided adhesive tape without a substrate material, with a layer of release film attached to the upper and lower layers of the adhesive layer. It is a type of pressure-sensitive adhesive. With the popularization of new applications such as consumer electronics, automotive electronics, and smart homes, the market demand for touch screen devices has expanded rapidly in recent years. In particular, the development of the flexible display industry has become a new growth driver for the industry, driving the market demand for optical adhesives. Compared with traditional acrylic optical adhesives, silicone optical adhesives have excellent high and low temperature resistance, weather resistance, and excellent optical properties, making them have a very large market prospect in the field of automotive display bonding and military display bonding.

[0003] At present, the main problem of silicone optical adhesive is the low adhesion, which reduces its applicability and cannot be applied to the bonding of all materials, especially in the bonding of substrates such as PMMA / PC / PET, where the adhesion performance is obviously insufficient, resulting in the development of foaming in subsequent tests and applications. The traditional solution is to add a small molecule coupling agent to the raw materials for the preparation of silicone optical adhesive, but the addition of a small molecule coupling agent is easy to absorb water and hydrolyze, resulting in a serious decrease in the optical properties of the material and the occurrence of fogging. In addition, in order to solve the problem of small molecule water absorption, a common solution is to obtain a thickener with a large molecular weight through a one-pot hydrolysis condensation between difunctional, trifunctional or tetrafunctional siloxane units, but the reaction structure of the thickener obtained by the hydrolysis condensation reaction is uncontrollable, especially when prepared with the participation of multifunctional monomers, the molecular structure of the thickener has a large steric hindrance, the residual alkoxy group has a low degree of freedom, the degree of improvement in the bonding performance is low, and the bonding force growth rate is slow. Generally, it takes more than 72 hours to reach the peak of the bonding force. The low initial adhesion and slow bonding growth rate lead to limited transfer and transportation of the bonded optical devices and low production efficiency.

[0004] Therefore, how to provide a tackifier with excellent performance that can enhance the adhesion of silicone optical adhesive, which can enhance the adhesion of silicone optical adhesive to materials such as PMMA / PC / PET without adversely affecting the optical properties of silicone optical adhesive, has become a technical problem that needs to be solved urgently. Summary of the invention

[0005] In view of the deficiencies of the prior art, the object of the present invention is to provide a tackifier and a preparation method thereof and an organic silicone optical adhesive. The present invention designs the composition of the tackifier and the structure of the polymer of formula I-III, and further designs the polymer of formula I-III to contain a polar group (acryloyloxy) and an alkoxy group, thereby preparing a tackifier with excellent performance. The organic silicone optical adhesive prepared from the tackifier has high bonding force and high optical performance.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a tackifier, wherein the tackifier comprises at least one of the polymers having the structures shown in Formula I to Formula III:

[0008]

[0009]

[0010] Among them, in the polymer of formula I, the polymer of formula II, and the polymer of formula III, R 1 Each is independently a C1-C5 alkyl group, R 2 Each is independently a C1-C5 alkyl group or a C2-C5 alkene group, R 3 Each is independently a C1-C5 alkyl group or a hydrogen atom;

[0011] In the polymer of formula I, the polymer of formula II and the polymer of formula III, n and m are each independently an integer of 1-20, and g is an integer selected from 1-5.

[0012] The present invention designs the composition of the tackifier and the structure of the polymer of formula I-III, and further designs the polymer of formula I-III to contain polar groups (acryloyloxy, * indicates the attachment site) and alkoxy (-OR 1 ), a tackifier with excellent performance was prepared, and the silicone optical adhesive prepared from the tackifier has high bonding strength and high optical properties.

[0013] In the prior art, small molecule coupling agents are often used as tackifiers, which are easy to absorb moisture in the air and hydrolyze, resulting in poor compatibility of the coupling agent, and finally the colloid is foggy, which cannot meet the optical performance requirements of display bonding. Compared with the small molecule coupling agents used in the prior art, the tackifier provided by the present invention has a larger molecular structure and the entire main chain is a silicon-oxygen-silicon structure, which makes it very compatible with other silicon-containing components of the silicone optical adhesive. At the same time, after its molecular weight increases, the spatial structure of the material itself changes, which can protect the siloxane structure from being easily hydrolyzed to a certain extent. Even if hydrolysis occurs, because the main chain of the material is a silicon-oxygen-silicon structure, its compatibility will not change much, which greatly improves the compatibility and long-term storage stability between the tackifier and other components of the silicone optical adhesive; and the alkoxy group is located at the free end of the tackifier, and the chain segment movement is easier, so that the tackifier forms hydrogen bonds with the polar groups on the surface of the substrate, which can quickly improve the adhesion of the silicone optical adhesive. Therefore, the tackifier provided by the present invention is not prone to fogging due to other problems such as water absorption, which may affect the optical properties of the product. It can effectively improve the bonding performance of silicone optical adhesive to PMMA / PC / PET materials without affecting the optical properties of silicone optical adhesive.

[0014] In the present invention, C1-C5 can be C1, C2, C3, C4 or C5.

[0015] n and m can each independently be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20.

[0016] g can be 1, 2, 3, 4, or 5.

[0017] It should be noted that the tackifier prepared by the preparation method provided by the present invention contains at least one of the polymers having structures shown in Formula I to Formula III, that is, the tackifier provided by the present invention is a mixture.

[0018] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0019] As a preferred technical solution of the present invention, the number average molecular weight of the tackifier is 500-2000, for example, it can be 500, 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900 or 2000.

[0020] Preferably, based on the mass percentage of the tackifier as 100%, the mass percentage of acryloxy in the tackifier is 15% to 35%, for example, it can be 15%, 16%, 18%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, 34% or 35%, etc.

[0021] In a second aspect, the present invention provides a method for preparing the tackifier as described in the first aspect, the preparation method comprising the following steps:

[0022] (1) mixing a difunctional acryloxysiloxane, a difunctional vinylsiloxane, a difunctional alkylsiloxane, and an acid catalyst solution, and reacting them to obtain a mixture;

[0023] (2) adding a trifunctional siloxane, a vinyl end-capping agent and a base catalyst to the reaction system obtained in step (1), reacting to obtain a prepolymer;

[0024] (3) adding trisiloxane hydrogen siloxane and a platinum catalyst to the prepolymer reaction system obtained in step (2), reacting to obtain the tackifier;

[0025] The solvent of the acid catalyst solution is water; based on the sum of the molar amounts of the difunctional acryloxysiloxane, the difunctional vinylsiloxane, and the difunctional alkylsiloxane as 1 mol, the amount of water in the acid catalyst solution is 1.5 to 4.0 mol (for example, 1.5 mol, 2.0 mol, 2.5 mol, 3.0 mol, 3.5 mol, or 4.0 mol, etc.);

[0026] The solvent of the alkaline catalyst solution is water; based on the sum of the molar amounts of the trifunctional siloxane and the vinyl end-capping agent as 1 mol, the molar amount of water in the alkaline catalyst solution is 1.0 to 2.0 mol (for example, 1.0 mol, 1.2 mol, 1.4 mol, 1.6 mol, 1.8 mol or 2.0 mol, etc.).

[0027] The present invention introduces a polar group (acryloxy group) into a tackifier by using an acryloxy-containing silane monomer (bifunctional acryloxysiloxane), thereby improving the adhesion of the organic silicone optical adhesive prepared by the tackifier to PMMA / PC / PET substrates; in terms of process, by controlling the amount of water used in the hydrolysis reaction in step (1) (provided by the solvent of the acid catalyst solution and the alkaline catalyst solution), a small amount of alkoxy groups are retained in the structure of the tackifier, and an alkoxy group is introduced at the end of the structure, so that the tackifier has the tackifying characteristics of a silane coupling agent. At the same time, the stability of the tackifier in the organic silicone optical adhesive is better than that of a conventional small molecule silane coupling agent, and it is not easy to cause fogging due to other problems such as water absorption to affect the optical properties of the product. The adhesion performance of the organic silicone optical adhesive to PMMA / PC / PET substrates can be effectively improved, and the optical properties of the organic silicone optical adhesive will not be affected.

[0028] As a preferred technical solution of the present invention, the difunctional acryloxysiloxane includes any one of 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylethyldiethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-acryloxypropylmethyldiethoxysilane or 3-methacryloxypropylethyldimethoxysilane, or a combination of at least two thereof.

[0029] Preferably, the difunctional vinyl siloxane comprises methylvinyldimethoxysilane and / or methylvinyldiethoxysilane.

[0030] Preferably, the difunctional alkylsiloxane includes any one of dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane or diethyldiethoxysilane, or a combination of at least two thereof.

[0031] Preferably, the mass concentration of the acid catalyst solution is 1-5% (eg, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, etc.).

[0032] Preferably, the acid catalyst in the acid catalyst solution comprises HCl, H 2 SO 4 , CH 3 Any one of COOH and trifluoromethanesulfonic acid or a combination of at least two thereof.

[0033] Preferably, the molar ratio of the difunctional acryloxysiloxane, the difunctional vinylsiloxane and the difunctional alkylsiloxane is 1:(0.1-0.6):(0.5-1.5), for example, it can be 1:0.1:0.5, 1:0.1:1, 1:0.1:1.5, 1:0.3:0.5, 1:0.3:1, 1:0.3:1.5, 1:0.6:0.5, 1:0.6:1 or 1:0.6:1.5, etc.

[0034] In the present invention, by controlling the molar ratio of difunctional acryloxysiloxane, difunctional vinylsiloxane, and difunctional alkylsiloxane within a specific range, a specific content of acryloxy is introduced into the tackifier, and a tackifier with excellent performance is prepared. If the amount of difunctional vinylsiloxane and difunctional alkylsiloxane is too much, the content of acryloxy in the tackifier is too little, and the tackifier prepared has poor tackifying effect and poor comprehensive performance, and thus the adhesion of the organic silicone optical adhesive prepared from the tackifier is poor; if the amount of difunctional vinylsiloxane and difunctional alkylsiloxane is too little, the content of acryloxy in the tackifier is too much, and the compatibility of the prepared tackifier becomes poor, the haze of the product becomes high, and the reaction rate is also affected, and thus the comprehensive performance of the organic silicone optical adhesive prepared from the tackifier is poor.

[0035] As a preferred technical solution of the present invention, the reaction temperature in step (1) is 50-70°C (for example, it can be 50°C, 52°C, 54°C, 56°C, 58°C, 60°C, 62°C, 64°C, 66°C, 68°C or 70°C, etc.), and the reaction time is 2-6h (for example, it can be 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h, etc.).

[0036] Preferably, the reaction in step (1) further includes a post-treatment step, and the post-treatment method includes: extraction and washing with water to neutrality.

[0037] Preferably, the solvent used for the extraction includes any one of cyclohexane, toluene or xylene, or a combination of at least two of them.

[0038] In the present invention, there is no special restriction on the order of adding the difunctional acryloxysiloxane, the difunctional vinylsiloxane, the difunctional alkylsiloxane and the acid catalyst, and the order of adding commonly used in the art is applicable, illustratively including but not limited to: after mixing the difunctional acryloxysiloxane, the difunctional vinylsiloxane and the difunctional alkylsiloxane, the acid catalyst is added thereto.

[0039] In the present invention, the acid catalyst solution can be added dropwise to the reaction system of step (1), and the dropping time is 30-60 min, for example, 30 min, 33 min, 36 min, 39 min, 42 min, 45 min, 48 min, 52 min, 55 min, 57 min or 60 min.

[0040] As a preferred technical solution of the present invention, the trifunctional siloxane includes any one of methyltriethoxysilane, methyltrimethoxysilane or ethyltriethoxysilane, or a combination of at least two thereof.

[0041] Preferably, the vinyl end-capping agent comprises tetramethyldivinyldisiloxane and / or tetramethyldivinyldisilazane.

[0042] Preferably, the mass concentration of the alkaline catalyst solution is 0.1-0.3% (for example, it may be 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, 0.22%, 0.24%, 0.26%, 0.28% or 0.3%, etc.).

[0043] Preferably, the alkaline catalyst includes any one of quaternary ammonium salt, potassium hydroxide, sodium hydroxide, or a combination of at least two thereof.

[0044] Preferably, the sum of the molar amounts of the difunctional acryloxysiloxane, the difunctional vinylsiloxane and the difunctional alkylsiloxane is 1 mol, and the molar amount of the trifunctional siloxane is 0.5-1.5 mol, for example, it can be 0.5 mol, 0.6 mol, 0.7 mol, 0.8 mol, 0.9 mol, 1 mol, 1.1 mol, 1.2 mol, 1.3 mol, 1.4 mol or 1.5 mol, etc.

[0045] Preferably, the molar amount of the vinyl end-capping agent is 0.1-0.3 mol, for example, 0.1 mol, 0.12 mol, 0.14 mol, 0.16 mol, 0.18 mol, 0.2 mol, 0.22 mol, 0.24 mol, 0.26 mol, 0.28 mol or 0.3 mol, etc., with the sum of the molar amounts of the difunctional acryloxysiloxane, the difunctional vinylsiloxane and the difunctional alkylsiloxane being 1 mol.

[0046] Preferably, the reaction time of step (2) is 90-110°C (for example, it can be 90°C, 92°C, 94°C, 96°C, 98°C, 100°C, 102°C, 104°C, 106°C, 108°C or 110°C, etc.), and the time is 2-6h (for example, it can be 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h, etc.).

[0047] Preferably, the step (2) further includes a post-treatment step after the reaction, and the post-treatment method includes: washing with water until neutral.

[0048] In the present invention, there is no particular restriction on the order of adding the trifunctional siloxane, the vinyl end-capping agent and the base catalyst to the reaction system obtained in step (1). Any order commonly used in the art is applicable, including but not limited to: first adding the trifunctional siloxane and the vinyl end-capping agent to the reaction system obtained in step (1), and then adding the base catalyst thereto.

[0049] As a preferred technical solution of the present invention, the trisiloxane-hydrogensiloxane includes trimethoxyhydrogensilane and / or triethoxyhydrogensilane.

[0050] Preferably, the molar ratio of the trisiloxane hydrogen siloxane in step (3) to the vinyl end-capping agent in step (2) is (0.5-1.1):1, for example, it can be 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1 or 1.1:1, etc.

[0051] In the present invention, by controlling the addition reaction of trisiloxane hydrogen siloxane with the vinyl group in the prepolymer of step (2), an alkoxy bond is introduced at the end of the tackifier, thereby improving the tackifying effect of the organic silicone optical adhesive containing the tackifier, and making the organic silicone optical adhesive reach the peak of the bonding force in a relatively short time; at the same time, by controlling the amount of trisiloxane hydrogen siloxane added, the present invention ensures that the tackifier can maintain a high bonding effect while avoiding the problem of fogging caused by the hydrolysis of the alkoxy group. If the amount of trisiloxane hydrogen siloxane is too small, the bonding effect of the prepared organic silicone optical adhesive is poor; if the amount of trisiloxane hydrogen siloxane is too large, the optical properties of the prepared organic silicone optical adhesive are poor.

[0052] Preferably, based on the mass percentage of the trisiloxane hydrogen siloxane as 100%, the mass content of the platinum catalyst is 10-50 ppm, for example, it can be 10 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm or 50 ppm.

[0053] Preferably, the platinum content in the platinum catalyst is 10% to 20%, for example, it can be 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%.

[0054] Preferably, the reaction temperature in step (3) is 80-100°C (for example, 80°C, 82°C, 84°C, 86°C, 88°C, 90°C, 92°C, 94°C, 96°C, 98°C or 100°C, etc.), and the reaction time is 2-4h (for example, 2h, 2.5h, 3h, 3.5h or 4h, etc.).

[0055] Preferably, step (3) further comprises a post-treatment step after the reaction, and the post-treatment method comprises reduced pressure distillation.

[0056] Preferably, the pressure of the reduced pressure distillation is -0.1 MPa to -0.01 MPa, for example, it can be -0.10 MPa, -0.08 MPa, -0.06 MPa, -0.05 MPa, -0.04 MPa, -0.02 MPa or -0.01 MPa.

[0057] As a preferred technical solution of the present invention, the preparation method of the tackifier specifically comprises the following steps:

[0058] (1) mixing a difunctional acryloxysiloxane, a difunctional vinylsiloxane and a difunctional alkylsiloxane, and dripping an acid catalyst solution thereto for 30-60 minutes. After the dripping is completed, reacting at 50-70° C. for 2-6 hours, extracting, and washing with water until neutral to obtain a mixture 1;

[0059] Wherein, the molar ratio of difunctional acryloxysiloxane, difunctional vinylsiloxane and difunctional alkylsiloxane is 1:(0.1-0.6):(0.5-1.5);

[0060] The mass percentage of the acid catalyst solution is 30-40%, based on the sum of the mass of the difunctional acryloxysiloxane, the difunctional vinylsiloxane, and the difunctional alkylsiloxane being 100%;

[0061] (2) adding trifunctional siloxane and vinyl end-capping agent to the reaction system obtained in step (1) and mixing, and then adding base catalyst solution thereto, the dripping time is 30-60 minutes, after the dripping is completed, reacting at 90-110° C. for 2-6 hours, washing with water until neutral, and obtaining a prepolymer;

[0062] Wherein, the sum of the molar amounts of the difunctional acryloxysiloxane, the difunctional vinylsiloxane and the difunctional alkylsiloxane is 1 mol, the molar amount of the trifunctional siloxane is 0.5-1.5 mol, and the molar amount of the vinyl end-capping agent is 0.1-0.3 mol;

[0063] The mass percentage of the alkaline catalyst solution is 15-30% based on the sum of the mass of the trifunctional siloxane and the vinyl end-capping agent as 100%;

[0064] (3) adding trisiloxane hydrogen siloxane and a platinum catalyst to the prepolymer reaction system obtained in step (2), reacting at 80-100° C. for 2-4 hours, and then reacting at -0.10 MPa to -0.01 MPa for 2 to 3 hours, removing low-boiling point products, and obtaining the tackifier;

[0065] Wherein, the molar ratio of the trisiloxane hydrogen siloxane in step (3) to the vinyl end-capping agent in step (2) is (0.5-1.1):1.

[0066] In a third aspect, the present invention provides an organic silicone optical adhesive, wherein the organic silicone optical adhesive comprises a first release film layer, an optical adhesive layer, and a second release film layer stacked in sequence;

[0067] The optical adhesive layer comprises the following components in parts by weight:

[0068]

[0069] In the present invention, by controlling the amount of the tackifier in the optical adhesive layer within a specific range, an organosilicon optical adhesive with excellent performance can be prepared. If the amount of the tackifier in the optical adhesive layer is too small, the adhesion of the prepared organosilicon optical adhesive is poor; if the amount of the tackifier in the optical adhesive layer is too large, the haze of the final product will be significantly increased, especially after aging under high temperature and high humidity conditions, the optical performance will be significantly reduced.

[0070] In the present invention, the weight proportion of the vinyl MQ resin in the optical adhesive layer may be 1 part, 2 parts, 4 parts, 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts or 20 parts.

[0071] The weight proportion of the low-viscosity vinyl silicone oil in the optical adhesive layer may be 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts or 60 parts.

[0072] The weight proportion of the high viscosity vinyl silicone oil in the optical adhesive layer may be 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, 55 parts or 60 parts, etc.

[0073] The weight proportion of the low-viscosity hydrogenated silicone oil in the optical adhesive layer may be 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, 27 parts, 30 parts, 33 parts, 36 parts, 38 parts or 40 parts, etc.

[0074] The weight proportion of the hydrogen-containing resin in the optical adhesive layer may be 0 part, 0.1 part, 0.2 part, 0.3 part, 0.4 part, 0.5 part, 0.6 part, 0.7 part, 0.8 part, 0.9 part or 1 part, etc.

[0075] The weight proportion of the tackifier as described in the first aspect in the optical adhesive layer can be 0.1 parts, 0.3 parts, 0.5 parts, 0.7 parts, 1 parts, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.2 parts, 2.5 parts, 2.7 parts or 3 parts, etc.

[0076] The weight proportion of the inhibitor in the optical adhesive layer may be 0.01 part, 0.02 part, 0.04 part, 0.06 part, 0.08 part, 0.1 part, 0.12 part, 0.14 part, 0.16 part, 0.18 part or 0.2 part, etc.

[0077] The weight proportion of the catalyst in the optical adhesive layer may be 0.001 part, 0.002 part, 0.005 part, 0.007 part, 0.01 part, 0.03 part, 0.05 part, 0.07 part, 0.08 part or 0.1 part, etc.

[0078] As a preferred technical solution of the present invention, the viscosity of the vinyl MQ resin at 25° C. is 10,000 to 150,000 cps (for example, it may be 10,000 cps, 20,000 cps, 40,000 cps, 60,000 cps, 80,000 cps, 100,000 cps, 120,000 cps, 140,000 cps or 150,000 cps, etc.), and the mass percentage of vinyl is 1 to 5% (for example, it may be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5% or 5%, etc.).

[0079] Preferably, the viscosity of the low-viscosity vinyl silicone oil at 25° C. is 500-2000cps (for example, 500cps, 700cps, 1000cps, 1200cps, 1400cps, 1600cps, 1800cps or 2000cps, etc.), and the mass percentage of vinyl is 0.2-0.5% (for example, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45% or 0.5%, etc.).

[0080] Preferably, the viscosity of the high-viscosity vinyl silicone oil at 25° C. is 100,000 to 250,000 cps (for example, 100,000 cps, 120,000 cps, 140,000 cps, 160,000 cps, 180,000 cps, 200,000 cps, 220,000 cps, 240,000 cps or 250,000 cps, etc.), and the mass percentage of vinyl is 0.01 to 0.04% (for example, 0.01%, 0.02%, 0.03% or 0.04%, etc.).

[0081] Preferably, the low-viscosity hydrogen-containing silicone oil has a viscosity of 50 to 200 cps at 25° C. (for example, 50 cps, 70 cps, 100 cps, 120 cps, 140 cps, 160 cps, 180 cps or 200 cps, etc.), and a hydrogen content of 0.2 to 0.5% (for example, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45% or 0.5%, etc.).

[0082] Preferably, the viscosity of the hydrogenated silicone resin at 25° C. is 500-2000 cps (for example, 500 cps, 700 cps, 1000 cps, 1200 cps, 1400 cps, 1600 cps, 1800 cps or 2000 cps, etc.), and the hydrogen content is 0.2-0.8% (for example, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7% or 0.8%, etc.).

[0083] Preferably, the inhibitor is at least one of ethynylcyclohexanol, 1,4-butynol or trimethylsilylpropynol, preferably ethynylcyclohexanol.

[0084] Preferably, the catalyst is at least one of chloroplatinic acid, bis(1,3-divinyl-1,1,3,3-tetramethyldisiloxane)platinum or ii-cyclopentadiene(trimethyl)platinum, preferably bis(1,3-divinyl-1,1,3,3-tetramethyldisiloxane)platinum.

[0085] As a preferred technical solution of the present invention, the first release film layer is a light release film.

[0086] Preferably, the release force of the light release film is 1 to 5 gf / 25mm, for example, it can be 1gf / 25mm, 1.5gf / 25mm, 2gf / 25mm, 2.5gf / 25mm, 3gf / 25mm, 3.5gf / 25mm, 4gf / 25mm, 4.5gf / 25mm or 5gf / 25mm.

[0087] Preferably, the second release film layer is a heavy release film layer.

[0088] Preferably, the release force of the heavy release film layer is 15-20 gf / 25mm, for example, it can be 15gf / 25mm, 15.5gf / 25mm, 16gf / 25mm, 16.5gf / 25mm, 17gf / 25mm, 17.5gf / 25mm, 18gf / 25mm, 18.5gf / 25mm, 19gf / 25mm, 19.5gf / 25mm or 20gf / 25mm, etc.

[0089] As a preferred technical solution of the present invention, the thickness of the optical adhesive layer is 0.02-2 mm, for example, it can be 0.02 mm, 0.05 mm, 0.1 mm, 0.2 mm, 0.4 mm, 0.6 mm, 0.8 mm, 1 mm, 1.2 mm, 1.4 mm, 1.6 mm, 1.8 mm or 2 mm.

[0090] In a fourth aspect, the present invention provides a use of the tackifier as described in the first aspect of the present invention or the silicone optical adhesive as described in the third aspect of the present invention in display screen bonding.

[0091] Compared with the prior art, the present invention has the following beneficial effects:

[0092] (1) The present invention designs the composition of the thickener and the structure of the polymer of formula I-III, and further designs the polymer of formula I-III to contain polar groups (acryloyloxy) and alkoxy groups, thereby preparing a thickener with excellent performance. The silicone optical adhesive prepared from the thickener has high adhesion and high optical properties.

[0093] (2) The present invention designs the raw materials for preparing the tackifier and further optimizes the comprehensive performance of the tackifier by controlling the amount of each component within a specific range, thereby improving the comprehensive performance of the silicone optical adhesive. DETAILED DESCRIPTION

[0094] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0095] The sources of some components in the embodiments and comparative examples are as follows:

[0096] Platinum catalyst: purchased from Anhui Mingyi Silicon Industry, brand MY8100.

[0097] Example 1

[0098] This embodiment provides a tackifier and a preparation method thereof. The preparation method of the tackifier is as follows:

[0099] (1) 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and dimethyldimethoxysilane were mixed, and an acid catalyst solution (hydrochloric acid, mass concentration of 3%) was added dropwise thereto for 50 min. After the addition was completed, the mixture was reacted at 60° C. for 4 h, extracted with cyclohexane, and washed with water until neutral to obtain a mixture;

[0100] Wherein, the molar ratio of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and dimethyldimethoxysilane is 1:0.4:1;

[0101] Based on the sum of the molar amounts of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and dimethyldimethoxysilane as 1 mol, the amount of water used in the acid catalyst solution is 3.2 mol;

[0102] (2) adding methyltriethoxysilane and tetramethyldivinyldisiloxane to the reaction system obtained in step (1) and mixing, and then adding an alkali catalyst solution (sodium hydroxide aqueous solution, mass concentration of 0.2%), the addition time is 50 minutes, after the addition is completed, reacting at 100° C. for 5 hours, washing with water until neutral, to obtain a prepolymer;

[0103] Wherein, the sum of the molar amounts of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and dimethyldimethoxysilane is 1 mol, the molar amount of the methyltriethoxysilane is 1.2 mol, and the molar amount of the tetramethyldivinyldisiloxane is 0.2 mol;

[0104] Based on the sum of the molar amounts of methyltriethoxysilane and tetramethyldivinyldisiloxane as 1 mol, the amount of water used in the alkaline catalyst solution is 1.5 mol;

[0105] (3) adding trimethoxysilane and a platinum catalyst to the prepolymer reaction system obtained in step (2), reacting at 90° C. for 3 h, and then reacting at −0.08 MPa for 2 h, removing low-boiling point products, and obtaining the tackifier;

[0106] The molar ratio of trimethoxysilane in step (3) to tetramethyldivinyldisiloxane in step (2) is 0.8:1, and the content of the platinum catalyst is 40 ppm, based on the mass percentage of trimethoxysilane being 100%.

[0107] Example 2

[0108] This embodiment provides a tackifier and a preparation method thereof. The preparation method of the tackifier is as follows:

[0109] (1) 3-methacryloxypropylmethyldiethoxysilane, methylvinyldiethoxysilane and dimethyldiethoxysilane were mixed, and an acid catalyst solution (trifluoromethanesulfonic acid aqueous solution, mass concentration of 3%) was added dropwise thereto for 35 min. After the addition was completed, the mixture was reacted at 50° C. for 6 h, extracted with cyclohexane, and washed with water until neutral to obtain a mixture;

[0110] Wherein, the molar ratio of 3-methacryloxypropylmethyldiethoxysilane, methylvinyldiethoxysilane and dimethyldiethoxysilane is 1:0.3:0.8;

[0111] Based on the sum of the molar amounts of 3-methacryloxypropylmethyldiethoxysilane, methylvinyldiethoxysilane and dimethyldiethoxysilane as 1 mol, the amount of water used in the acid catalyst solution is 1.8 mol;

[0112] (2) adding methyltrimethoxysilane and tetramethyldivinyldisiloxane to the reaction system obtained in step (1) and mixing, and then adding an alkali catalyst solution (aqueous potassium hydroxide solution, with a mass concentration of 0.2%), the addition time is 40 minutes, after the addition is completed, reacting at 90° C. for 5 hours, washing with water until neutral, to obtain a prepolymer;

[0113] Wherein, the sum of the molar amounts of 3-methacryloxypropylmethyldiethoxysilane, methylvinyldiethoxysilane and dimethyldiethoxysilane is 1 mol, the molar amount of the methyltrimethoxysilane is 0.8 mol, and the molar amount of the tetramethyldivinyldisiloxane is 0.1 mol;

[0114] The amount of water in the alkaline catalyst solution is 1 mol, based on the sum of the molar amounts of methyltriethoxysilane and tetramethyldivinyldisiloxane as 1 mol;

[0115] (3) adding triethoxysilane and a platinum catalyst to the prepolymer reaction system obtained in step (2), reacting at 80° C. for 4 h, and then reacting at −0.02 MPa for 2 h, removing low-boiling point products, and obtaining the tackifier;

[0116] The molar ratio of the triethoxyhydrogensilane in step (3) to the tetramethyldivinyldisiloxane in step (2) is 1.1:1, and the content of the platinum catalyst is 40 ppm, based on the mass percentage of the triethoxyhydrogensilane being 100%.

[0117] Example 3

[0118] This embodiment provides a tackifier and a preparation method thereof. The preparation method of the tackifier is as follows:

[0119] (1) 3-methacryloxypropylethyldiethoxysilane, methylvinyldiethoxysilane and diethyldimethoxysilane were mixed, and an acid catalyst solution (hydrochloric acid, mass concentration of 3%) was added dropwise thereto for 60 minutes. After the addition was completed, the mixture was reacted at 70° C. for 3 hours, extracted with cyclohexane, and washed with water until neutral to obtain a mixture;

[0120] Wherein, the molar ratio of 3-methacryloxypropylethyldiethoxysilane, methylvinyldiethoxysilane and diethyldimethoxysilane is 1:0.5:1.2;

[0121] Based on the sum of the molar amounts of 3-methacryloxypropylethyldiethoxysilane, methylvinyldiethoxysilane and diethyldimethoxysilane as 1 mol, the amount of water used in the acid catalyst solution is 3.8 mol;

[0122] (2) adding ethyltriethoxysilane and tetramethyldivinyldisiloxane to the reaction system obtained in step (1) and mixing, and then adding an alkali catalyst solution (aqueous potassium hydroxide solution, with a mass concentration of 0.2%), the addition time is 60 minutes, after the addition is completed, reacting at 110° C. for 3 hours, washing with water until neutral, to obtain a prepolymer;

[0123] Wherein, the sum of the molar amounts of 3-methacryloxypropylethyldiethoxysilane, methylvinyldiethoxysilane and diethyldimethoxysilane is 1 mol, the molar amount of the ethyltriethoxysilane is 0.5 mol, and the molar amount of the tetramethyldivinyldisiloxane is 0.3 mol;

[0124] Based on the sum of the molar amounts of ethyltriethoxysilane and tetramethyldivinyldisiloxane as 1 mol, the amount of water used in the alkaline catalyst solution is 2 mol;

[0125] (3) adding triethoxysilane and a platinum catalyst to the prepolymer reaction system obtained in step (2), reacting at 100° C. for 2 h, and then reacting at −0.03 MPa for 2 h, removing low-boiling point products, and obtaining the tackifier;

[0126] The molar ratio of the triethoxysilane in step (3) to the tetramethyldivinyldisiloxane in step (2) is 0.5:1, and the content of the platinum catalyst is 40 ppm, based on the mass percentage of the triethoxysilane being 100%.

[0127] Example 4

[0128] This embodiment provides a tackifier and a preparation method thereof. The preparation method of the tackifier is as follows:

[0129] (1) 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and dimethyldimethoxysilane were mixed, and an acid catalyst solution (hydrochloric acid, mass concentration of 3%) was added dropwise thereto for 50 min. After the addition was completed, the mixture was reacted at 60° C. for 4 h, extracted with cyclohexane, and washed with water until neutral to obtain a mixture;

[0130] Wherein, the molar ratio of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and dimethyldimethoxysilane is 1:0.1:1.5;

[0131] Based on the sum of the molar amounts of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and dimethyldimethoxysilane as 1 mol, the amount of water used in the acid catalyst solution is 3 mol;

[0132] (2) adding methyltriethoxysilane and tetramethyldivinyldisiloxane to the reaction system obtained in step (1) and mixing, and then adding an alkali catalyst solution (sodium hydroxide aqueous solution, mass concentration of 0.2%), the addition time is 50 minutes, after the addition is completed, reacting at 100° C. for 5 hours, washing with water until neutral, to obtain a prepolymer;

[0133] Wherein, the sum of the molar amounts of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and dimethyldimethoxysilane is 1 mol, the molar amount of the methyltriethoxysilane is 1 mol, and the molar amount of the tetramethyldivinyldisiloxane is 0.2 mol;

[0134] Based on the sum of the molar amounts of methyltriethoxysilane and tetramethyldivinyldisiloxane as 1 mol, the amount of water used in the alkaline catalyst solution is 1.5 mol;

[0135] (3) adding trimethoxysilane and a platinum catalyst to the prepolymer reaction system obtained in step (2), reacting at 90° C. for 3 h, and then reacting at −0.01 MPa for 2 h, removing low-boiling point products, and obtaining the tackifier;

[0136] The molar ratio of trimethoxysilane in step (3) to tetramethyldivinyldisiloxane in step (2) is 0.8:1, and the content of the platinum catalyst is 40 ppm, based on the mass percentage of trimethoxysilane being 100%.

[0137] Example 5

[0138] This embodiment provides a tackifier and a preparation method thereof. The preparation method of the tackifier is as follows:

[0139] (1) 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and diethyldiethoxysilane were mixed, and an acid catalyst solution (dilute sulfuric acid, mass concentration of 3%) was added dropwise thereto for 50 min. After the addition was completed, the mixture was reacted at 60° C. for 4 h, extracted with cyclohexane, and washed with water until neutral to obtain a mixture;

[0140] Wherein, the molar ratio of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and diethyldiethoxysilane is 1:0.6:0.5;

[0141] Based on the sum of the molar amounts of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and diethyldiethoxysilane as 1 mol, the amount of water used in the acid catalyst solution is 2.5 mol;

[0142] (2) adding methyltriethoxysilane and tetramethyldivinyldisiloxane to the reaction system obtained in step (1) and mixing, and then adding an alkali catalyst solution (sodium hydroxide aqueous solution, mass concentration of 0.2%), the addition time is 50 minutes, after the addition is completed, reacting at 100° C. for 5 hours, washing with water until neutral, to obtain a prepolymer;

[0143] Wherein, the sum of the molar amounts of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and diethyldiethoxysilane is 1 mol, the molar amount of the methyltriethoxysilane is 1.5 mol, and the molar amount of the tetramethyldivinyldisiloxane is 0.2 mol;

[0144] Based on the sum of the molar amounts of methyltriethoxysilane and tetramethyldivinyldisiloxane as 1 mol, the amount of water used in the alkaline catalyst solution is 1.5 mol;

[0145] (3) adding trimethoxysilane and a platinum catalyst to the prepolymer reaction system obtained in step (2), reacting at 90° C. for 3 h, and then reacting at −0.06 MPa for 2 h, removing low-boiling point products, and obtaining the tackifier;

[0146] The molar ratio of trimethoxysilane in step (3) to tetramethyldivinyldisiloxane in step (2) is 0.8:1, and the content of the platinum catalyst is 40 ppm, based on the mass percentage of trimethoxysilane being 100%.

[0147] Example 6-Example 13

[0148] Embodiments 6 to 13 respectively provide a tackifier and a preparation method thereof, which differ from Embodiment 1 only in that:

[0149] Example 6: In step (1), the molar ratio of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and diethyldiethoxysilane is 1:0.6:1.5;

[0150] Example 7: In step (1), the molar ratio of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and diethyldiethoxysilane is 1:0.1:0.5;

[0151] Example 8: In step (1), the molar ratio of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and diethyldiethoxysilane is 0.7:0.6:1.5;

[0152] Example 9: In step (1), the molar ratio of 3-methacryloxypropylmethyldimethoxysilane, methylvinyldimethoxysilane and diethyldiethoxysilane is 1.4:0.1:0.5;

[0153] Example 10: The molar ratio of trimethoxysilane in step (3) to tetramethyldivinyldisiloxane in step (2) is 0.5:1;

[0154] Example 11: The molar ratio of trimethoxysilane in step (3) to tetramethyldivinyldisiloxane in step (2) is 1.1:1;

[0155] Example 12: The molar ratio of trimethoxysilane in step (3) to tetramethyldivinyldisiloxane in step (2) is 0.3:1;

[0156] Example 13: The molar ratio of trimethoxysilane in step (3) to tetramethyldivinyldisiloxane in step (2) is 1.4:1;

[0157] Other conditions are the same as in Example 1.

[0158] Comparative Example 1-Comparative Example 3

[0159] This comparative example provides a tackifier and a preparation method thereof, which differs from Example 1 only in that:

[0160] Comparative Example 1: 3-methacryloxypropylmethyldimethoxysilane was not used in step (1);

[0161] Comparative Example 2: Step (3) was not performed;

[0162] Comparative Example 3: In step (2), tetramethyldivinyldisiloxane is replaced with an equimolar amount of a siloxane mixture, wherein the siloxane mixture is composed of hexamethyldisiloxane and tetramethyldivinyldisiloxane in a molar ratio of 1:1;

[0163] Other conditions are the same as in Example 1.

[0164] Comparative Example 4

[0165] This comparative example provides a tackifier, which is KH560 (γ-glycidyloxypropyltrimethoxysilane).

[0166] Comparative Example 5

[0167] This comparative example provides a tackifier, which is KH570 (γ-(methacryloyloxy)propyltrimethoxysilane).

[0168] The tackifiers provided in the above examples and comparative examples were tested and characterized as follows:

[0169] Number average molecular weight: The sample was injected with tetrahydrofuran as the mobile phase (concentration of 0.02 g / mL), the injection volume was 10 μL, the flow rate was 1 mL / min, and the standard curve was prepared with polystyrene as the standard sample. The test was performed with a Waters 2414 differential refractometer at 40°C.

[0170] The mass percentage of acryloyloxy in the tackifier was measured using a German Bruker AvanceⅢ400MHzSuperconducting Fourier NMR spectrometer at room temperature, with deuterated chloroform (CDCl 3 ).

[0171] The above performance test results are detailed in Table 1 below:

[0172] Table 1

[0173]

[0174]

[0175] The sources of some components in the following application examples and comparative examples are shown in Table 2 below:

[0176] Table 2

[0177]

[0178] Application Examples 1-13 and Comparative Application Examples 1-3

[0179] Application Examples 1 to 13 and Comparative Application Examples 1 to 3 respectively provide a silicone optical adhesive and a preparation method thereof, wherein the silicone optical adhesive comprises a first release film layer, an optical adhesive layer, and a second release film layer stacked in sequence;

[0180] The components of the optical adhesive layer are shown in Table 3 and Table 4 below. The amounts of the components in Table 3 and Table 4 are all in parts by weight.

[0181] The preparation method of the above-mentioned organic silicon optical adhesive is as follows:

[0182] The components of the optical adhesive layer, vinyl resin, vinyl silicone oil, hydrogen-containing resin, hydrogen-containing silicone oil, inhibitor and tackifier, are added into a stirring container in sequence and stirred for 30 minutes. Then, a catalyst is added and stirring is continued for 5 minutes before vacuum defoaming. Finally, a scraper is used to evenly scrape the defoamed adhesive liquid on the surface of the heavy release film (release force is 20gf / 25mm) with a scraping thickness of 0.5mm. After the scraping is completed, it is placed in a 60°C oven for curing for 20 minutes, and then covered with a light release film (release force is 2gf / 25mm), and allowed to cool to obtain a silicone optical adhesive.

[0183] Table 3

[0184]

[0185]

[0186] Table 4

[0187]

[0188] The performance of the organic silicone optical adhesive provided in the above application examples and comparative application examples was tested, and the specific test method is as follows:

[0189] Shear strength: tested according to GB / T 7124-2008;

[0190] Pull-out strength: tested according to GB / T 31541-2015;

[0191] Peel force: tested according to GB / T 2792-1998;

[0192] Haze: Tested according to GB / T 2410 7.1.

[0193] The above performance test results are detailed in Tables 5 and 6 below.

[0194] Table 5

[0195]

[0196] Table 6

[0197]

[0198]

[0199] From the above content, it can be seen that the present invention designs the composition of the tackifier and the structure of the polymer of formula I-III, and further designs the polymer of formula I-III to contain polar groups (acryloyloxy) and alkoxy groups, thereby preparing a tackifier with excellent performance. The silicone optical adhesive prepared from the tackifier has high adhesion and high optical properties. The 24H peeling force on the glass substrate is 10.3-14.5N / 25mm, the 48H peeling force is 13.1-15.2N / 25mm, the 72H peeling force is 14.3-15.5N / 25mm, the pulling force is 162-192N / 25mm, the shear force is 123-188N / 25mm, the initial haze is 0.04-0.12, and the haze after double 85 aging for 1000h is 2.26-3.32.

[0200] It can be seen from Examples 1 and 6-13 that the present invention designs the molar ratio of difunctional acryloxysiloxane, difunctional vinylsiloxane, and difunctional alkylsiloxane in the preparation raw materials of the tackifier to be within a specific range, so that the polar groups (acryloxy) and alkoxy groups contained in the polymers of Formulas I-III are within a specific range, thereby further improving the comprehensive performance of the tackifier. The silicone optical adhesive prepared from the tackifier has higher adhesion and higher optical properties.

[0201] It can be seen from Example 1 and Comparative Examples 1-3 that the present invention designs the raw materials for preparing the tackifier and further regulates the specific composition and structure of the tackifier to prepare a tackifier with excellent performance, and then prepares a silicone optical adhesive with excellent comprehensive performance.

[0202] It can be seen from Example 1 and Comparative Examples 4-5 that, compared with the small molecule thickener used in the prior art, the use of the thickener provided by the present invention further improves the mechanical properties and optical properties of the silicone optical adhesive.

[0203] In summary, the present invention further optimizes the comprehensive performance of the tackifier and improves the comprehensive performance of the silicone optical adhesive by designing the raw materials for preparing the tackifier and controlling the amount of each component within a specific range.

[0204] The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A tackifier, characterized in that The tackifier comprises at least one of the polymers having the structures shown in Formula I to Formula III: Wherein, in the polymer of formula I, the polymer of formula II, and the polymer of formula III, R1 is each independently a C1-C5 alkyl group, R2 is each independently a C1-C5 alkyl group or a C2-C5 olefin group, and R3 is each independently a C1-C5 alkyl group or a hydrogen atom; In the polymer of formula I, the polymer of formula II and the polymer of formula III, n and m are each independently an integer of 1-20, and g is an integer selected from 1-5.

2. The tackifier according to claim 1, characterized in that The number average molecular weight of the tackifier is 500 to 2000; Preferably, based on the mass percentage of the tackifier being 100%, the mass percentage of the acryloxy group in the tackifier is 15% to 35%.

3. A method for preparing a tackifier as claimed in claim 1 or 2, characterized in that: The preparation method comprises the following steps: (1) mixing a difunctional acryloxysiloxane, a difunctional vinylsiloxane, a difunctional alkylsiloxane, and an acid catalyst solution, and reacting them to obtain a mixture; (2) adding a trifunctional siloxane, a vinyl end-capping agent and a base catalyst to the reaction system obtained in step (1), reacting to obtain a prepolymer; (3) adding trisiloxane hydrogen siloxane and a platinum catalyst to the prepolymer reaction system obtained in step (2), reacting to obtain the tackifier; The solvent of the acid catalyst solution is water; based on the sum of the molar amounts of the difunctional acryloxysiloxane, the difunctional vinylsiloxane, and the difunctional alkylsiloxane as 1 mol, the amount of water in the acid catalyst solution is 1.5 to 4.0 mol; The solvent of the alkaline catalyst solution is water. Based on the sum of the molar amounts of the trifunctional siloxane and the vinyl end-capping agent as 1 mol, the molar amount of water in the alkaline catalyst solution is 1.0 to 2.0 mol.

4. The preparation method according to claim 3, characterized in that: The difunctional acryloxysiloxane includes any one of 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylethyldiethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-acryloxypropylmethyldiethoxysilane or 3-methacryloxypropylethyldimethoxysilane, or a combination of at least two thereof; Preferably, the difunctional vinyl siloxane comprises methylvinyldimethoxysilane and / or methylvinyldiethoxysilane; Preferably, the difunctional alkylsiloxane includes any one of dimethyldimethoxysilane, dimethyldiethoxysilane, diethyldimethoxysilane or diethyldiethoxysilane, or a combination of at least two thereof; Preferably, the mass concentration of the acid catalyst solution is 1-5%; Preferably, the acid catalyst in the acid catalyst solution includes any one of HCl, H2SO4, CH3COOH, trifluoromethanesulfonic acid or a combination of at least two thereof; Preferably, the molar ratio of the difunctional acryloxysiloxane, the difunctional vinylsiloxane, and the difunctional alkylsiloxane is 1:(0.1-0.6):(0.5-1.5); Preferably, the reaction temperature in step (1) is 50-70°C and the reaction time is 2-6h; Preferably, the step (1) further comprises a post-treatment step after the reaction, and the post-treatment method comprises: extraction and washing with water until neutral; Preferably, the solvent used for the extraction includes any one of cyclohexane, toluene or xylene, or a combination of at least two of them.

5. The preparation method according to claim 3 or 4, characterized in that: The trifunctional siloxane includes any one of methyltriethoxysilane, methyltrimethoxysilane or ethyltriethoxysilane or a combination of at least two thereof; Preferably, the vinyl end-capping agent comprises tetramethyldivinyldisiloxane and / or tetramethyldivinyldisilazane; Preferably, the mass concentration of the alkaline catalyst solution is 0.1-0.3%; Preferably, the alkaline catalyst comprises any one of quaternary ammonium salt, potassium hydroxide, sodium hydroxide or a combination of at least two thereof; Preferably, the total molar amount of the difunctional acryloxysiloxane, the difunctional vinylsiloxane, and the difunctional alkylsiloxane is 1 mol, and the molar amount of the trifunctional siloxane is 0.5-1.5 mol; Preferably, the molar amount of the vinyl end-capping agent is 0.1-0.3 mol, based on the sum of the molar amounts of the difunctional acryloxysiloxane, the difunctional vinylsiloxane, and the difunctional alkylsiloxane being 1 mol; Preferably, the reaction time in step (2) is 90-110° C. for 2-6 h; Preferably, the reaction in step (2) further includes a post-treatment step, and the post-treatment method includes: washing with water until neutral.

6. The preparation method according to any one of claims 3 to 5, characterized in that: The trisiloxane hydrogen siloxane includes trimethoxy hydrogen silane and / or triethoxy hydrogen silane; Preferably, the molar ratio of the trisiloxane hydrogen siloxane in step (3) to the vinyl end-capping agent in step (2) is (0.5-1.1):1; Preferably, based on the mass percentage of the trisiloxane hydrogen siloxane being 100%, the mass content of the platinum catalyst is 10-50 ppm; Preferably, the platinum content in the platinum catalyst is 10% to 20%; Preferably, the reaction temperature in step (3) is 80-100°C and the reaction time is 2-4h; Preferably, step (3) further comprises a post-treatment step after the reaction, and the post-treatment method comprises reduced pressure distillation; Preferably, the pressure of the reduced pressure distillation is -0.1 MPa to -0.01 MPa.

7. An organic silicone optical adhesive, characterized in that: The organic silicon optical adhesive comprises a first release film layer, an optical adhesive layer, and a second release film layer which are stacked in sequence; The optical adhesive layer comprises the following components in parts by weight:

8. The organic silicone optical adhesive according to claim 7, characterized in that: The viscosity of the vinyl MQ resin at 25° C. is 10,000 to 150,000 cps, and the mass percentage of vinyl is 1 to 5%; Preferably, the viscosity of the low-viscosity vinyl silicone oil at 25° C. is 500 to 2000 cps, and the mass percentage of vinyl is 0.2 to 0.5%; Preferably, the viscosity of the high-viscosity vinyl silicone oil at 25° C. is 100,000 to 250,000 cps, and the mass percentage of vinyl is 0.01 to 0.04%; Preferably, the low-viscosity hydrogenated silicone oil has a viscosity of 50 to 200 cps at 25°C and a hydrogen content of 0.2 to 0.5%; Preferably, the hydrogen-containing silicone resin has a viscosity of 500 to 2000 cps at 25° C. and a hydrogen content of 0.2 to 0.8%; Preferably, the inhibitor is at least one of ethynylcyclohexanol, 1,4-butynol or trimethylsilylpropynol, preferably ethynylcyclohexanol; Preferably, the catalyst is at least one of chloroplatinic acid, bis(1,3-divinyl-1,1,3,3-tetramethyldisiloxane)platinum or ii-cyclopentadiene(trimethyl)platinum, preferably bis(1,3-divinyl-1,1,3,3-tetramethyldisiloxane)platinum.

9. The organic silicon optical adhesive according to claim 7 or 8, characterized in that: The first release film layer is a light release film; Preferably, the release force of the light release film is 1 to 5 gf / 25 mm; Preferably, the second release film layer is a heavy release film layer; Preferably, the release force of the heavy release film layer is 15 to 20 gf / 25 mm; The thickness of the optical adhesive layer is 0.02-2 mm.

10. Use of the tackifier according to any one of claims 1 to 2 or the silicone optical adhesive according to any one of claims 7 to 9 in display screen bonding.

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