Flexible epoxy glue modified organic silicon adhesive as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of adhesive preparation, and particularly relates to a flexible epoxy adhesive modified organic silicon adhesive and a preparation method and application thereof.The flexible epoxy adhesive modified organic silicon adhesive is composed of a component A and a component B, the component A is prepared from 40-70 parts of vinyl-terminated silicone oil, 10-30 parts of hydrogen-containing silicone oil, 5-20 parts of filler, 1-5 parts of coupling agent and 1-10 parts of curing agent; and the component B comprises the following components in parts by weight: 60-70 parts of vinyl-terminated silicone oil, 5-20 parts of epoxy resin, 5-15 parts of a platinum catalyst, 1-5 parts of an accelerant, 1-5 parts of an inhibitor and 5-20 parts of filler. Epoxy resin is introduced into an organic silicon matrix and is matched with a toughening agent and a catalyst, so that efficient combination of a two-phase system is realized, and the adhesive which is stable in performance, high in adhesive force and excellent in flexibility is obtained and has excellent comprehensive performance and application prospects in electronic packaging, automobile part bonding and building sealing.

Description

Technical Field

[0001] The invention belongs to the technical field of adhesive preparation, and specifically relates to a flexible epoxy modified organic silicone adhesive and a preparation method and application thereof. Background Art

[0002] With the development of industrial technology, the demand for high-performance adhesives in the fields of electronic packaging, automotive parts bonding, building sealing, etc. is increasing. These application scenarios usually require adhesives to have excellent weather resistance, high temperature resistance, electrical insulation and reliable adhesion. In such applications, silicone adhesives have become a widely used type of adhesive due to their excellent high temperature resistance, flexibility and weather resistance. However, traditional silicone adhesives have certain limitations in adhesion and strength in extreme temperature environments, especially in certain dynamic load-bearing environments, where they are prone to falling off or failure due to lack of sufficient flexibility and strength.

[0003] Epoxy resin is widely used in adhesives due to its excellent adhesion, chemical resistance and mechanical strength. However, conventional epoxy resin is usually relatively rigid after curing, lacks elasticity and flexibility, and cannot adapt well to thermal expansion and contraction or dynamic load environments. Flexible epoxy resin provides a certain degree of flexibility while maintaining the excellent adhesion of epoxy resin, which can better make up for the shortcomings of traditional epoxy resin. Therefore, compounding and modifying flexible epoxy resin with silicone matrix is ​​expected to achieve complementary performance of the two, so that the adhesive has both high strength and excellent flexibility to meet a variety of application requirements.

[0004] The existing modification technologies mainly focus on adding fillers or special functional additives to the silicone matrix, but these modification methods are mainly based on improving specific single properties and cannot systematically improve the adhesion, flexibility and weather resistance of the adhesive. Therefore, the development of a flexible epoxy modified silicone adhesive that can improve adhesion, flexibility and environmental adaptability while maintaining the high temperature resistance of silicone adhesive has become an important direction for the development of technology in this field. Summary of the invention

[0005] The purpose of the present invention is to provide a flexible epoxy modified organic silicone adhesive and its preparation method and application. Vinyl silicone oil with suitable viscosity is selected to be compounded with flexible epoxy resin and cured with a suitable curing system. The present invention combines the excellent high temperature resistance, weather resistance and electrical insulation properties of organic silicone adhesive with the high adhesion and flexibility of flexible epoxy resin, thereby making up for the deficiencies of traditional organic silicone adhesive in adhesion, dynamic load resistance and structural strength. The flexible epoxy modified organic silicone adhesive exhibits excellent comprehensive performance in various application fields such as electronic packaging, automotive parts bonding and building sealing, and has broad application prospects.

[0006] In order to achieve the above object, the technical solution of the present invention is:

[0007] In the first aspect, the present invention provides a flexible epoxy modified organic silicone adhesive, which is composed of component A and component B. Component A is composed of the following raw materials by weight: 40-70 parts of vinyl-terminated silicone oil, 10-30 parts of hydrogen-containing silicone oil, 5-20 parts of filler, 1-5 parts of coupling agent, and 1-10 parts of curing agent;

[0008] Component B is composed of the following raw materials: 60-70 parts of vinyl-terminated silicone oil, 5-20 parts of epoxy resin, 5-15 parts of platinum catalyst, 1-5 parts of accelerator, 1-5 parts of inhibitor, and 5-20 parts of filler.

[0009] In some other embodiments, the mixing mass ratio of the A component and the B component is 1:(1-2);

[0010] Preferably, the mixing mass ratio of component A to component B is 1:1.

[0011] In some other embodiments, in component A or component B, the vinyl-terminated silicone oil is one of vinyl-terminated polydimethylsiloxane and vinyl-terminated polymethylvinylsiloxane;

[0012] The vinyl content of the vinyl-terminated silicone oil is 0.03-0.74 mmoles / g and the viscosity is 450-2000 mPa.s;

[0013] Preferably, the vinyl-terminated silicone oil is vinyl-terminated polydimethylsiloxane with a vinyl content of 0.16 mmoles / g and a viscosity of 1000 mPa.s.

[0014] In some other embodiments, in component A, the hydrogen silicone oil is hydroxy-terminated polydimethylsiloxane;

[0015] The hydrogen content of the hydrogen-containing silicone oil is 0.18-0.75% and the viscosity is 30-100mpa.s;

[0016] Preferably, the hydrogen content of the hydrogen-containing silicone oil is 0.18% and the viscosity is 100 mPa.s.

[0017] In some other embodiments, in component A or component B, the filler is one or more of white carbon black, calcium carbonate, kaolin, talc and silicon dioxide, and the particle size is 800-2000 mesh;

[0018] Preferably, the filler is white carbon black with a particle size of 1000 mesh;

[0019] Or, in component A, the coupling agent is a silane coupling agent having a bifunctional group, and the silane coupling agent having a bifunctional group is at least one of γ-glycidyloxypropyltrimethoxysilane and γ-aminopropyltriethoxysilane;

[0020] Alternatively, the curing agent is one of dicyandiamide, diaminodiphenyl ether and diaminodiphenyl sulfone.

[0021] In some other embodiments, in component B, the epoxy resin is a bisphenol A epoxy resin;

[0022] Or, the platinum catalyst is one of chloroplatinic acid and Custer catalyst;

[0023] Or, the accelerator is one of ACS-MA-9100 and ACS-MA-9000;

[0024] Alternatively, the inhibitor is one of ethynylcycloethanol and 3,7,11-trimethyldodecyn-3-ol.

[0025] The inventors discovered during the research process that terminal vinyl silicone oil and hydrogen-containing silicone oil are used as silicone matrices to provide adhesives with high temperature resistance, weather resistance and electrical insulation properties.

[0026] Epoxy resins are used to improve the adhesion and flexibility of adhesives, making them highly adaptable to dynamic loads and temperature fluctuations.

[0027] Coupling agents are used to enhance the bonding strength between epoxy resin and silicone matrix, and improve the impact resistance and mechanical strength of the adhesive.

[0028] Catalysts are used to accelerate the cross-linking reaction, improve the curing efficiency and form a uniform cross-linking structure.

[0029] Curing agent is used for the cross-linking reaction of flexible epoxy resin.

[0030] Accelerators are used to enhance the adhesion between adhesives and substrates.

[0031] Inhibitors are used to adjust the curing time and reaction speed of the adhesive to prevent excessive reaction from causing uneven curing of silicone rubber and the generation of bubbles.

[0032] Fillers are used to increase the hardness, compressive strength and impact toughness of adhesives.

[0033] The inventive concept adopted by the present invention is: a flexible epoxy resin with specific active functional groups (such as amino, hydroxyl, etc.) and an organosilicon polymer containing reactive groups (such as vinyl, etc.) are used as basic raw materials. During the curing process at 120-150°C, the amino groups in the epoxy resin and the vinyl groups in the organosilicon polymer undergo addition reactions to form a chemically bonded network structure. This chemical bonding not only enhances the compatibility between the two polymers, but also enables the adhesive to have both the strength of the epoxy resin and the flexibility of the organosilicon after curing, effectively improving the problem of the difficulty in balancing strength and flexibility in traditional adhesives. By selecting a flexible epoxy resin with a suitable structure, regulating the viscosity of the vinyl silicone oil and the ratio between the two, an effective interaction between specific functional groups is achieved, thereby giving the adhesive excellent performance.

[0034] In addition, the inventors also tried to add a small amount of flexible segment regulators, such as polyester polyols with specific structures. The ester groups in polyester polyols have weak interactions with some functional groups in epoxy resins and silicones, which can effectively reduce the interaction between polymer molecular chains and increase the mobility of molecular chains, thereby improving the flexibility and low-temperature performance of the adhesive. However, adding too much will cause the strength of the adhesive to decrease.

[0035] The invention introduces a specific proportion of flexible epoxy resin into an organic silicon matrix and combines it with suitable toughening agents, catalysts and other components to achieve efficient combination of a two-phase system, thereby obtaining an adhesive with stable performance, strong adhesion and excellent flexibility.

[0036] In a second aspect, the present invention provides a method for preparing the flexible epoxy modified organic silicone adhesive according to the first aspect, comprising the following steps:

[0037] Preparation of component A: Vinyl-terminated silicone oil, hydrogen-containing silicone oil, filler, coupling agent and curing agent are stirred and mixed at room temperature, and then vacuum degassed to obtain component A;

[0038] Preparation of component B: Vinyl-terminated silicone oil, epoxy resin, platinum catalyst, accelerator, inhibitor and filler are stirred and mixed at room temperature, and then component B is vacuum degassed;

[0039] The component A and the component B are mixed to obtain a flexible epoxy modified organic silicone adhesive.

[0040] In some other embodiments, during the preparation of component A or component B, the stirring and mixing speed is 100-500 rpm, the time is 1-2 hours, and the vacuum degassing is evacuated to -0.1 MPa and maintained for 30-60 minutes;

[0041] Preferably, during the preparation of component A or component B, the stirring and mixing speed is 300 rpm, the time is 1 hour, and the vacuum degassing is evacuated to -0.1 MPa and maintained for 60 minutes.

[0042] The organosilicon matrix (terminated vinyl silicone oil and hydrogen silicone oil) in component A of the present invention and the epoxy resin in component B need to be uniformly mixed and fully combined under mild conditions by appropriate stirring equipment, thereby improving the uniformity of the system and preventing the premature occurrence of local cross-linking reactions. The mixed component A or component B is degassed under low pressure to remove bubbles generated during the stirring process, thereby ensuring the uniformity of the adhesive and the adhesion strength after curing.

[0043] In a third aspect, the present invention provides the use of the flexible epoxy modified organic silicone adhesive described in the first aspect in electronic packaging, automotive parts bonding and building sealing.

[0044] In a fourth aspect, the present invention provides a method for using the flexible epoxy modified silicone adhesive described in the first aspect, wherein component A and component B are mixed and then applied or sprayed on the surface of the base material, and cured at room temperature or under heating for 30 minutes to 2 hours; the heating temperature is 120-150°C and the curing time is 30-60 minutes.

[0045] During the use of the flexible epoxy modified organic silicone adhesive of the present invention, component A and component B are mixed on site and then applied or sprayed on the surface of the base material, and the final bonding structure can be formed after curing at room temperature. In order to improve the curing speed, it is suitable for occasions with high requirements for curing efficiency. Curing is performed at a temperature of 120°C to 150°C, and the curing time varies from 30 minutes to 2 hours depending on the temperature. The base material is a metal substrate, and the metal substrate is stainless steel or copper sheet.

[0046] Beneficial effects of the present invention:

[0047] (1) Compared with the traditional method of adding inorganic fillers to silicone, the present invention uses flexible epoxy glue to modify the silicone adhesive, so that the adhesive liquid state is more uniform, the addition amount is more adjustable, the various properties of the silicone adhesive can be better balanced, and the tensile shear strength is better improved.

[0048] (2) The flexible epoxy modified organic silicone adhesive of the present invention has better stability, a tensile strength of ≥2.0 MPa after curing, and significantly improved hardness. DETAILED DESCRIPTION

[0049] 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 making creative work are within the scope of protection of the present invention.

[0050] A flexible epoxy modified organic silicone adhesive, composed of component A and component B, wherein component A is composed of the following raw materials by weight: 40-70 parts of vinyl-terminated silicone oil, 10-30 parts of hydrogen-containing silicone oil, 5-20 parts of filler, 1-5 parts of coupling agent, and 1-10 parts of curing agent;

[0051] Component B is composed of the following raw materials: 60-70 parts of vinyl-terminated silicone oil, 5-20 parts of epoxy resin, 5-15 parts of platinum catalyst, 1-5 parts of accelerator, 1-5 parts of inhibitor, and 5-20 parts of filler.

[0052] The vinyl-terminated silicone oil, hydrogen-containing silicone oil, Custer catalyst, ACS-MA-9100 and ethynyl cycloethanol used in the embodiments of the present invention were purchased from Shanghai Sibao High-tech Materials Co., Ltd., white carbon black was purchased from Suzhou Gadison New Materials Technology Co., Ltd., γ-aminopropyltriethoxysilane was purchased from Nanjing Jingtianwei Chemical Co., Ltd., dicyandiamide was purchased from Guangzhou Yihuisheng Chemical Co., Ltd., and bisphenol A epoxy resin EBA-30 was purchased from Shanghai Huayi Resin Co., Ltd.

[0053] Example 1

[0054] A flexible epoxy modified organic silicone adhesive, the raw material compositions of component A and component B are shown in Table 1 below:

[0055] Table 1 Formula composition of flexible epoxy modified silicone adhesive

[0056]

[0057]

[0058] The preparation method of the flexible epoxy modified organic silicone adhesive comprises the following steps:

[0059] According to the ratio in Table 1, vinyl-terminated silicone oil, hydrogenated silicone oil (viscosity of 100 mPa·s), γ-aminopropyltriethoxysilane, white carbon black (model TS720) and dicyandiamide were weighed into a beaker, stirred evenly at 300 rpm at room temperature, and evacuated to -0.1 MPa for 60 min to eliminate bubbles, so as to obtain component A for standby use.

[0060] According to the ratio in Table 1, vinyl-terminated silicone oil, flexible epoxy resin, platinum catalyst, accelerator, inhibitor, and white carbon black (model TS720) were weighed into a beaker, stirred evenly at 300 rpm at room temperature, and evacuated to -0.1 MPa for 60 minutes to eliminate bubbles, to obtain component B for later use.

[0061] Mix component A and component B in a mass ratio of 1:1 for gluing.

[0062] Example 2

[0063] A flexible epoxy modified organic silicone adhesive, the raw material compositions of its component A and component B are shown in Table 2 below:

[0064] Table 2 Formula composition of flexible epoxy modified silicone adhesive

[0065]

[0066]

[0067] The preparation method of the flexible epoxy modified organic silicone adhesive is different from the preparation process of Example 1 in that the mixing conditions of component A and component B are: stirring evenly at a speed of 300 rpm at room temperature, and evacuating to -0.1 MPa for 30 minutes to eliminate bubbles.

[0068] Mix component A and component B in a mass ratio of 1:1 for gluing.

[0069] Example 3

[0070] A flexible epoxy modified organic silicone adhesive, the raw material compositions of its component A and component B are shown in Table 3 below:

[0071] Table 3 Formula composition of flexible epoxy modified silicone adhesive

[0072]

[0073]

[0074] The preparation method of the flexible epoxy modified organic silicone adhesive is different from the preparation process of Example 1 in that the mixing conditions of component A and component B are: stirring evenly at a speed of 300 rpm at room temperature, and evacuating to -0.1 MPa for 60 minutes to eliminate bubbles.

[0075] Mix component A and component B in a mass ratio of 1:1.2 for gluing.

[0076] Comparative Example 1

[0077] A flexible epoxy modified organic silicone adhesive, the raw material compositions of its component A and component B are shown in Table 4 below:

[0078] Table 4 Formula composition of organic silicone adhesive

[0079]

[0080]

[0081] The preparation method of the common organic silicone adhesive is different from the preparation process of Example 1 in that component A and component B are mixed in a mass ratio of 1:2 for sizing, and the other preparation steps are exactly the same as those of Example 1.

[0082] Comparative Example 2

[0083] Commercially available organic silicone adhesive (584T from Qinglongda (Shanxi) Science and Technology New Materials Co., Ltd.).

[0084] Comparative Example 3

[0085] Commercially available adhesive containing epoxy resin (Huiju Adhesive HJ-379 transparent potting glue).

[0086] Performance Test:

[0087] The performance tests of the organic silicone adhesives prepared in Examples 1-3 and Comparative Examples 1-3 were performed, and the results are shown in Table 5;

[0088] Conduct tensile shear strength test according to GB / T 7124-2008;

[0089] Hardness test method after curing: According to GB / T 531.1-2008, use a hardness tester to test separately, curing conditions 150℃ / 60min;

[0090] 5% thermal decomposition temperature, also known as "weight loss temperature", refers to the temperature at which the mass of the sample decreases by 5% during heating. It is mainly used to evaluate the thermal stability of the sample.

[0091] Measure electrical strength according to GB / T 1408.1-2016;

[0092] Elongation at break: A universal material testing machine is used for tensile testing. By recording the force-displacement curve of the sample during the stretching process, key parameters such as elongation at break can be calculated.

[0093] Table 5 Tensile shear strength performance test of silicone adhesive

[0094]

[0095]

[0096] As can be seen from Table 5, the addition of flexible epoxy resin in Examples 1-3 enables the epoxy resin to play a role in strengthening the performance of the adhesive as a whole. Combined with the excellent high temperature resistance and weather resistance of the organic silicone adhesive, the epoxy resin and the organic silicone form a uniform whole after curing, so that the tensile shear strength and hardness are significantly improved. The tensile shear strength of the organic silicone adhesive in Example 1 without adding flexible epoxy glue as a reinforcing component is higher. Comparative Example 2 is a commercially available two-component organic silicone adhesive. In the case of not using a flexible epoxy resin component for modification, the tensile strength of the adhesive is relatively low. Comparative Example 3 is a commercially available flexible epoxy resin adhesive. In the case of no modification, the tensile shear strength is relatively high, but the elongation at break is relatively low.

[0097] It can be seen that the present invention utilizes flexible epoxy resin to modify the organic silicone adhesive, while maintaining the high tensile shear strength of the flexible epoxy adhesive, effectively improving the elongation at break of the adhesive, and combining the advantages of the organic silicone adhesive and the flexible epoxy adhesive to a limited extent. The epoxy resin and organic silicone adhesive system forms a uniform polymer dispersion system, which exhibits a homogeneous interpenetrating network structure and plays a synergistic role.

[0098] In summary, the present invention selects vinyl silicone oil with suitable viscosity and epoxy resin with flexible structure, and selects a suitable curing system to prepare a flexible epoxy modified organic silicone adhesive, aiming to improve the flexibility, adhesion and durability of the organic silicone adhesive, while maintaining its excellent high temperature resistance and bonding strength. The present invention introduces a specific proportion of flexible epoxy resin into the organic silicone matrix, and cooperates with a suitable toughening agent and catalyst to achieve efficient combination of the two-phase system, thereby obtaining an adhesive with stable performance, strong adhesion and excellent flexibility.

Claims

1. A flexible epoxy modified organic silicone adhesive, characterized in that: The method is composed of component A and component B. Component A is composed of the following raw materials by weight: 40-70 parts of vinyl-terminated silicone oil, 10-30 parts of hydrogen-containing silicone oil, 5-20 parts of filler, 1-5 parts of coupling agent, and 1-10 parts of curing agent. Component B is composed of the following raw materials: 60-70 parts of vinyl-terminated silicone oil, 5-20 parts of epoxy resin, 5-15 parts of platinum catalyst, 1-5 parts of accelerator, 1-5 parts of inhibitor, and 5-20 parts of filler.

2. The flexible epoxy modified organic silicone adhesive according to claim 1, characterized in that: The mixing mass ratio of the A component and the B component is 1:(1-2); Preferably, the mixing mass ratio of component A to component B is 1:

1.

3. The flexible epoxy modified organic silicone adhesive according to claim 1, characterized in that: In component A or component B, the vinyl-terminated silicone oil is one of vinyl-terminated polydimethylsiloxane and vinyl-terminated polymethylvinylsiloxane; The vinyl content of the vinyl-terminated silicone oil is 0.03-0.74 mmoles / g and the viscosity is 450-2000 mPa.s; Preferably, the vinyl-terminated silicone oil is vinyl-terminated polydimethylsiloxane with a vinyl content of 0.16 mmoles / g and a viscosity of 1000 mPa.s.

4. The flexible epoxy modified organic silicone adhesive according to claim 1, characterized in that: In component A, the hydrogen-containing silicone oil is hydroxy-terminated polydimethylsiloxane; The hydrogen content of the hydrogen-containing silicone oil is 0.18-0.75% and the viscosity is 30-100mpa.s; Preferably, the hydrogen content of the hydrogen-containing silicone oil is 0.18% and the viscosity is 100 mPa.s.

5. The flexible epoxy modified organic silicone adhesive according to claim 1, characterized in that: In component A or component B, the filler is one or more of white carbon black, calcium carbonate, kaolin, talc and silicon dioxide, and the particle size is 800-2000 mesh; Preferably, the filler is white carbon black with a particle size of 1000 mesh; Or, in component A, the coupling agent is a silane coupling agent having a bifunctional group, and the silane coupling agent having a bifunctional group is at least one of γ-glycidyloxypropyltrimethoxysilane and γ-aminopropyltriethoxysilane; Alternatively, the curing agent is one of dicyandiamide, diaminodiphenyl ether and diaminodiphenyl sulfone.

6. The flexible epoxy modified organic silicone adhesive according to claim 1, characterized in that: In component B, the epoxy resin is bisphenol A epoxy resin; Or, the platinum catalyst is one of chloroplatinic acid and Custer catalyst; Or, the accelerator is one of ACS-MA-9100 and ACS-MA-9000; Alternatively, the inhibitor is one of ethynylcycloethanol and 3,7,11-trimethyldodecyn-3-ol.

7. A method for preparing the flexible epoxy modified organic silicone adhesive according to any one of claims 1 to 6, characterized in that: The following steps are involved: Preparation of component A: Vinyl-terminated silicone oil, hydrogen-containing silicone oil, filler, coupling agent and curing agent are stirred and mixed at room temperature, and then vacuum degassed to obtain component A; Preparation of component B: Vinyl-terminated silicone oil, epoxy resin, platinum catalyst, accelerator, inhibitor and filler are stirred and mixed at room temperature, and then component B is vacuum degassed; The component A and the component B are mixed to obtain a flexible epoxy modified organic silicone adhesive.

8. The method for preparing the flexible epoxy modified organic silicone adhesive according to claim 7, characterized in that: During the preparation of component A or component B, the stirring and mixing speed is 100-500 rpm, the time is 1-2 hours, and the vacuum degassing is to evacuate to -0.1 MPa and maintain for 30-60 minutes; Preferably, during the preparation of component A or component B, the stirring and mixing speed is 300 rpm, the time is 1 hour, and the vacuum degassing is evacuating to -0.1 MPa and maintaining it for 60 minutes.

9. Use of the flexible epoxy modified organic silicone adhesive according to any one of claims 1 to 6 in electronic packaging, automotive parts bonding and building sealing.

10. A method for using the flexible epoxy modified organic silicone adhesive according to any one of claims 1 to 6, characterized in that: Mix component A and component B and apply or spray them on the surface of the base material, and cure them at room temperature or under heating for 30 minutes to 2 hours; the heating temperature is 120-150°C and the curing time is 30-60 minutes.

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