Organic silicon adhesive and preparation method thereof

Abstract

The invention discloses an organic silicon adhesive and a preparation method thereof, and relates to the technical field of high polymer materials. The preparation method comprises the following steps: putting tetraethoxysilane and hydroxyl-terminated polydimethylsiloxane into a reaction kettle 2, then adding dibutyltin dilaurate, a silane coupling agent, a filler and maleic alcohol, stirring and mixing, and then vacuumizing to remove bubbles, thereby obtaining the organic silicon adhesive. The organic silicon adhesive prepared by the invention has excellent water resistance and mechanical properties.

Description

Technical Field

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

[0002] Organic silicone adhesives are a type of siloxane composition with bonding and sealing properties. They are generally cured by adding different organic silicone matrix additives and fillers under heating, room temperature or radiation conditions to obtain silicone rubber composite materials that meet various requirements. Compared with epoxy system adhesives and polyurethane system adhesives, organic silicone adhesives are widely used in new technology fields such as solar energy, aerospace, LED lighting and automobiles due to their unique high and low temperature resistance and weather resistance. However, their weak adhesion to metals limits their application. Therefore, it is urgent to develop an organic silicone adhesive suitable for metal surfaces. Summary of the invention

[0003] The object of the present invention is to provide an organic silicone adhesive and a preparation method thereof to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] An organic silicone adhesive comprises the following raw materials in parts by weight:

[0006]

[0007] Dibutyltin dilaurate 0.03-0.05 parts

[0008] Preferably, the silane coupling agent is any one of silane coupling agent KH550, silane coupling agent KH560 or silane coupling agent KH570.

[0009] Preferably, the filler is calcium carbonate or silicon dioxide.

[0010] A method for preparing an organic silicone adhesive comprises the following steps:

[0011] (1) By weight, take 20-30 parts of hydroxyl-terminated polydimethylsiloxane, 1-2 parts of silane coupling agent, 3-5 parts of filler, 1-2 parts of maleic alcohol, 3-5 parts of ethyl orthosilicate, and 0.03-0.05 parts of dibutyltin dilaurate;

[0012] (2) placing tetraethyl orthosilicate and hydroxyl-terminated polydimethylsiloxane in a reaction kettle 2, then adding dibutyltin dilaurate, a silane coupling agent, a filler, and maleic alcohol, stirring and mixing at a rotation speed of 800-1000 r / min for 20-30 minutes, and then vacuuming to remove bubbles, thereby obtaining an organic silicone adhesive.

[0013] Preferably, the hydroxyl-terminated polydimethylsiloxane may be a modified hydroxyl-terminated polydimethylsiloxane.

[0014] Preferably, the preparation method of the modified hydroxyl-terminated polydimethylsiloxane is:

[0015] By weight, 10-20 parts of N-acetyl-L-cysteine, 60-80 parts of ethanol, 10-20 parts of hydroxyl-terminated polydimethylsiloxane, 0.3-0.5 parts of photoinitiator and 80-100 parts of tetrahydrofuran are taken, N-acetyl-L-cysteine ​​and ethanol are placed in a mixing kettle 1, and stirred and mixed for 30-50 minutes at a rotation speed of 800-1000 r / min to obtain a dissolving solution A, then the hydroxyl-terminated polydimethylsiloxane, the photoinitiator and the tetrahydrofuran are placed in a mixing kettle 2, and stirred and mixed for 30-50 minutes at a rotation speed of 800-1000 r / min to obtain a dissolving solution B, then the dissolving solution A and the dissolving solution B are placed in a reaction kettle, and are placed under 365nm ultraviolet light for 1-1.2 hours while being irradiated with light, and then the temperature is increased to remove the ethanol and tetrahydrofuran in the reaction kettle 1 to obtain a modified hydroxyl-terminated polydimethylsiloxane.

[0016] Preferably, the photoinitiator is 2,2-dimethoxy-2-phenylacetophenone.

[0017] In summary, due to the adoption of the above technology, the beneficial effects of the present invention are:

[0018] The invention, firstly, by grafting N-acetyl-L-cysteine ​​to the hydroxyl-terminated polydimethylsiloxane side chain, the number of hydrogen bonds in the system is increased, the number of physical crosslinking points is increased, the crosslinking density is increased, and the mechanical properties of the system are enhanced. At the same time, the introduction of N-acetyl-L-cysteine ​​will increase the number of bonds formed between the polar groups therein and water, thereby increasing the hydrophilicity of the system. However, the number of hydrogen bonds within and between the molecules is more, the hydrophilic groups are fixed inside the system, and the hydrophobic methyl groups are more exposed on the surface, thereby further enhancing the hydrophobicity of the system. Secondly, when bonding with metal, the carbonyl groups in the adhesive generate coordination bonds, the molecular weight is small, the molecular chain is short, and the adhesive has better wettability on a metal plate with a large surface energy, thereby further improving the mechanical properties of the metal surface of the product. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than 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 belong to the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0020] Example 1

[0021] A method for preparing an organic silicone adhesive comprises the following steps:

[0022] (1) By weight, take 20 parts of modified hydroxyl-terminated polydimethylsiloxane, 1 part of silane coupling agent, 5 parts of filler, 1 part of maleic alcohol, 5 parts of ethyl orthosilicate, and 0.05 parts of dibutyltin dilaurate;

[0023] (2) placing tetraethyl orthosilicate and modified hydroxyl-terminated polydimethylsiloxane in a reaction kettle 2, then adding dibutyltin dilaurate, a silane coupling agent, a filler, and maleic alcohol, stirring and mixing at a speed of 800 r / min for 30 minutes, and then vacuuming to remove bubbles, thereby obtaining an organic silicone adhesive.

[0024] The silane coupling agent is silane coupling agent KH550.

[0025] The filler is silicon dioxide.

[0026] The preparation method of modified hydroxyl-terminated polydimethylsiloxane is:

[0027] By weight, 10 parts of N-acetyl-L-cysteine, 80 parts of ethanol, 10 parts of hydroxyl-terminated polydimethylsiloxane, 0.5 parts of photoinitiator and 80 parts of tetrahydrofuran are taken, N-acetyl-L-cysteine ​​and ethanol are placed in a mixing kettle 1, and stirred and mixed for 50 minutes at a rotation speed of 800 r / min to obtain a dissolving solution A, then the hydroxyl-terminated polydimethylsiloxane, the photoinitiator and the tetrahydrofuran are placed in a mixing kettle 2, and stirred and mixed for 50 minutes at a rotation speed of 1000 r / min to obtain a dissolving solution B, then the dissolving solution A and the dissolving solution B are placed in a reaction kettle, and placed under 365nm ultraviolet light for 1 hour while stirring and reacting, and then the temperature is increased to remove the ethanol and tetrahydrofuran in the reaction kettle 1 to obtain a modified hydroxyl-terminated polydimethylsiloxane.

[0028] The photoinitiator was 2,2-dimethoxy-2-phenylacetophenone.

[0029] Example 2

[0030] A method for preparing an organic silicone adhesive comprises the following steps:

[0031] (1) By weight, take 30 parts of modified hydroxyl-terminated polydimethylsiloxane, 2 parts of silane coupling agent, 4 parts of filler, 2 parts of maleic alcohol, 3 parts of ethyl orthosilicate, and 0.05 parts of dibutyltin dilaurate;

[0032] (2) placing tetraethyl orthosilicate and modified hydroxyl-terminated polydimethylsiloxane in a reaction kettle 2, then adding dibutyltin dilaurate, a silane coupling agent, a filler, and maleic alcohol, stirring and mixing at a speed of 800 r / min for 30 minutes, and then vacuuming to remove bubbles, thereby obtaining an organic silicone adhesive.

[0033] The silane coupling agent is silane coupling agent KH560.

[0034] The filler is calcium carbonate.

[0035] The preparation method of modified hydroxyl-terminated polydimethylsiloxane is:

[0036] By weight, 10 parts of N-acetyl-L-cysteine, 80 parts of ethanol, 10 parts of hydroxyl-terminated polydimethylsiloxane, 0.5 parts of photoinitiator and 80 parts of tetrahydrofuran are taken, N-acetyl-L-cysteine ​​and ethanol are placed in a mixing kettle 1, and stirred and mixed for 30 minutes at a rotation speed of 1000 r / min to obtain a dissolving solution A, then the hydroxyl-terminated polydimethylsiloxane, the photoinitiator and the tetrahydrofuran are placed in a mixing kettle 2, and stirred and mixed for 50 minutes at a rotation speed of 1000 r / min to obtain a dissolving solution B, then the dissolving solution A and the dissolving solution B are placed in a reactor, and placed under 365nm ultraviolet light while stirring and reacting for 1.2 hours, and then the temperature is increased to remove the ethanol and tetrahydrofuran in the reactor 1 to obtain a modified hydroxyl-terminated polydimethylsiloxane.

[0037] The photoinitiator was 2,2-dimethoxy-2-phenylacetophenone.

[0038] Example 3

[0039] A method for preparing an organic silicone adhesive comprises the following steps:

[0040] (1) By weight, take 20 parts of modified hydroxyl-terminated polydimethylsiloxane, 2 parts of silane coupling agent, 3 parts of filler, 2 parts of maleic alcohol, 5 parts of ethyl orthosilicate, and 0.04 parts of dibutyltin dilaurate;

[0041] (2) placing tetraethyl orthosilicate and modified hydroxyl-terminated polydimethylsiloxane in a reaction kettle 2, then adding dibutyltin dilaurate, a silane coupling agent, a filler, and maleic alcohol, stirring and mixing at a rotation speed of 900 r / min for 30 minutes, and then vacuuming to remove bubbles, thereby obtaining an organic silicone adhesive.

[0042] The silane coupling agent is silane coupling agent KH550.

[0043] The filler is calcium carbonate.

[0044] The preparation method of modified hydroxyl-terminated polydimethylsiloxane is:

[0045] By weight, 20 parts of N-acetyl-L-cysteine, 70 parts of ethanol, 20 parts of hydroxyl-terminated polydimethylsiloxane, 0.3 parts of photoinitiator and 100 parts of tetrahydrofuran are taken, N-acetyl-L-cysteine ​​and ethanol are placed in a mixing kettle 1, and stirred and mixed for 30 minutes at a rotation speed of 1000 r / min to obtain a dissolving solution A, then the hydroxyl-terminated polydimethylsiloxane, the photoinitiator and the tetrahydrofuran are placed in a mixing kettle 2, and stirred and mixed for 50 minutes at a rotation speed of 1000 r / min to obtain a dissolving solution B, then the dissolving solution A and the dissolving solution B are placed in a reactor, and placed under 365nm ultraviolet light while stirring and reacting for 1.2 hours, and then the temperature is increased to remove the ethanol and tetrahydrofuran in the reactor 1 to obtain a modified hydroxyl-terminated polydimethylsiloxane.

[0046] The photoinitiator was 2,2-dimethoxy-2-phenylacetophenone.

[0047] Comparative Example 1

[0048] A method for preparing an organic silicone adhesive comprises the following steps:

[0049] (1) By weight, take 20 parts of hydroxyl-terminated polydimethylsiloxane, 2 parts of silane coupling agent, 3 parts of filler, 2 parts of maleic alcohol, 5 parts of ethyl orthosilicate, and 0.04 parts of dibutyltin dilaurate;

[0050] (2) Putting tetraethyl orthosilicate and hydroxyl-terminated polydimethylsiloxane into a reaction kettle 2, then adding dibutyltin dilaurate, a silane coupling agent, a filler, and maleic alcohol, stirring and mixing at a rotation speed of 900 r / min for 30 minutes, and then vacuuming to remove bubbles, thereby obtaining an organic silicone adhesive.

[0051] The silane coupling agent is silane coupling agent KH550.

[0052] The filler is calcium carbonate.

[0053] Detection method:

[0054] 1. Water resistance: Use ASTPRODUCTS INC contact angle tester to test the water contact angle of the sample. Place a flat sample on the test bench, drop a 2μL water droplet on it, use a camera to record the water droplet image and measure the contact angle. Each sample is measured at different positions, and the average value is taken after 5 measurements.

[0055] 2. Shear strength: Use the UTM4204 electronic universal testing machine of Shenzhen SUNTHINK Technology Co., Ltd. to test the shear resistance of the overlapped test specimens. Use a special clamp to fix the overlapped specimens on the tensile machine, so that the force center line of each metal sheet remains vertical, the tensile rate is 5mm / min, and the maximum force is recorded. Five samples are tested for each group of samples and the average value is taken. The calculation formula for tensile shear strength is:

[0056] τ=P / B×L

[0057] Where τ represents the tensile shear strength (MPa), P represents the maximum load when the specimen fails in shear (N), B represents the width of the specimen overlap surface (mm), and L represents the length of the specimen overlap surface (mm).

[0058] Table 1:

[0059]

[0060] From the data comparison in Table 1, it can be seen that the present invention grafts N-acetyl-L-cysteine ​​to the hydroxyl-terminated polydimethylsiloxane side chain, so that the hydrogen bonds in the system are increased, the physical crosslinking points are increased, the crosslinking density is increased, and the mechanical properties are enhanced. At the same time, the introduction of N-acetyl-L-cysteine ​​will lead to an increase in the bonds formed between the polar groups and water, thereby increasing the hydrophilicity of the system. However, there are more hydrogen bonds within and between the molecules, the hydrophilic groups are fixed inside the system, and the hydrophobic methyl groups are more exposed on the surface, thereby further enhancing the hydrophobicity of the system. Secondly, when bonding with metal, the carbonyl groups in the adhesive produce coordination bonds, the molecular weight is small, the molecular chain is short, and the metal plate with larger surface energy has better wettability, so that the mechanical properties of the metal surface of the product can be further improved.

[0061] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

[0062] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device.

Claims

1. An organic silicone adhesive, characterized in that: The invention comprises the following raw materials in parts by weight:

2. The organic silicone adhesive according to claim 1, characterized in that: The silane coupling agent is any one of silane coupling agent KH550, silane coupling agent KH560 or silane coupling agent KH570.

3. The organic silicone adhesive according to claim 1, characterized in that: The filler is any one of calcium carbonate or silicon dioxide.

4. A method for preparing an organic silicone adhesive, characterized in that: The method comprises the following preparation steps: (1) By weight, take 20-30 parts of hydroxyl-terminated polydimethylsiloxane, 1-2 parts of silane coupling agent, 3-5 parts of filler, 1-2 parts of maleic alcohol, 3-5 parts of ethyl orthosilicate, and 0.03-0.05 parts of dibutyltin dilaurate; (2) placing tetraethyl orthosilicate and hydroxyl-terminated polydimethylsiloxane in a reaction kettle 2, then adding dibutyltin dilaurate, a silane coupling agent, a filler, and maleic alcohol, stirring and mixing at a rotation speed of 800-1000 r / min for 20-30 minutes, and then vacuuming to remove bubbles, thereby obtaining an organic silicone adhesive.

5. The method for preparing an organic silicone adhesive according to claim 4, characterized in that: The hydroxyl-terminated polydimethylsiloxane may also be a modified hydroxyl-terminated polydimethylsiloxane.

6. The method for preparing an organic silicone adhesive according to claim 5, characterized in that: The preparation method of the modified hydroxyl-terminated polydimethylsiloxane is: By weight, 10-20 parts of N-acetyl-L-cysteine, 60-80 parts of ethanol, 10-20 parts of hydroxyl-terminated polydimethylsiloxane, 0.3-0.5 parts of photoinitiator and 80-100 parts of tetrahydrofuran are taken, N-acetyl-L-cysteine ​​and ethanol are placed in a mixing kettle 1, and stirred and mixed for 30-50 minutes at a rotation speed of 800-1000 r / min to obtain a dissolving solution A, then the hydroxyl-terminated polydimethylsiloxane, the photoinitiator and the tetrahydrofuran are placed in a mixing kettle 2, and stirred and mixed for 30-50 minutes at a rotation speed of 800-1000 r / min to obtain a dissolving solution B, then the dissolving solution A and the dissolving solution B are placed in a reaction kettle, and are placed under 365nm ultraviolet light for 1-1.2 hours while being irradiated with light, and then the temperature is increased to remove the ethanol and tetrahydrofuran in the reaction kettle 1 to obtain a modified hydroxyl-terminated polydimethylsiloxane.

7. The method for preparing an organic silicone adhesive according to claim 6, characterized in that: The photoinitiator is 2,2-dimethoxy-2-phenylacetophenone.

Images