Organosilicon pressure-sensitive adhesive with low glass transition temperature, high modulus and high viscosity and preparation method thereof

Abstract

The invention discloses an organosilicon pressure-sensitive adhesive with low glass transition temperature, high modulus and high viscosity and a preparation method thereof. The pressure-sensitive adhesive is prepared from the following raw materials in parts by weight: 90-150 parts of amino vinyl silicone oil, 90-150 parts of vinyl MQ silicon resin, 10-30 parts of methyl MQ silicon resin, 1.5-15 parts of hydrogen-containing silicone oil, 1-5 parts of a catalyst, 1-5 parts of an inhibitor and 50-100 parts of a solvent. The low glass transition temperature, the high modulus and the high viscosity are compatible, the modulus comprises the energy storage modulus and the elastic modulus, and the viscosity comprises the viscosity of common base materials such as steel plates, copper foils, PET and PI. The technical bottlenecks of low glass transition temperature, low modulus and low viscosity or high glass transition temperature, high modulus and high viscosity of the conventional organic silicon pressure-sensitive adhesive are broken, and the application field of the organic silicon pressure-sensitive adhesive is expanded.

Description

Technical Field

[0001] The present invention relates to the field of organosilicon pressure-sensitive adhesives, and in particular to an organosilicon pressure-sensitive adhesive with low glass transition temperature, high modulus and high viscosity and a preparation method thereof. Background Art

[0002] Pressure-sensitive adhesives are pressure-sensitive adhesives that dry at room temperature and exhibit both dry and permanent adhesion. Pressure-sensitive tape is the primary form of pressure-sensitive adhesive. Applying slight pressure with your fingers or palm allows the tape to adhere securely to the substrate and peel away without leaving any residue. Pressure-sensitive tapes have a wide range of applications in all aspects of our daily lives.

[0003] Silicone pressure-sensitive adhesives are more prominently used in certain special occasions due to their excellent aging resistance and excellent adhesion to low surface energy interfaces (polytetrafluoroethylene, silicone rubber, etc.). Conventional silicone pressure-sensitive adhesives have a characteristic: modulus and viscosity are strongly positively correlated with the glass transition temperature (tg). Silicone pressure-sensitive adhesives with lower tg points will also have lower modulus and viscosity, and their cohesive strength and mechanical properties will be weak, limiting their application.

[0004] Therefore, it is necessary to improve the existing technology to provide a more reliable solution. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive and a preparation method thereof in view of the deficiencies in the above-mentioned prior art.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is: in the first aspect of the present invention, a low glass transition temperature, high modulus and high viscosity silicone pressure-sensitive adhesive and a preparation method thereof are provided, wherein the raw materials for the preparation include the following components by weight: 90-150 parts of amino vinyl silicone oil, 1.5-15 parts of hydrogen-containing silicone oil, 90-150 parts of vinyl MQ silicone resin, 10-30 parts of methyl MQ silicone resin, 1-5 parts of catalyst, 1-5 parts of inhibitor, and 50-100 parts of solvent.

[0007] Preferably, the aminovinyl silicone oil is a linear polymer, and the structural formula is as follows:

[0008]

[0009] Wherein a, b, and c are the polymerization degrees of the repeating units; R1 is an alkyl group having 1 to 8 carbon atoms; R2 is a methyl group or a vinyl group; R3 is a methyl group or a vinyl group; and R4 is an amino group.

[0010] Preferably, the mass content of vinyl groups in the aminovinyl silicone oil is 0.05%-1.6%, and the mass content of amino groups is 0.08-0.25%.

[0011] Preferably, the aminovinyl silicone oil is prepared by the following method:

[0012] After nitrogen is introduced into the container, tetramethylammonium hydroxide catalyst and D4 (octamethylcyclotetrasiloxane), vinyltrichlorosilane are added, and the mixture is heated to 110-130°C while stirring. After reacting for 4-16 hours for hydrolysis and chain extension, aminopropyltrimethoxysilane, tetramethyldivinylsiloxane or hexamethyldisilazane end-capping agent is added, and the reaction is continued for 4-16 hours. The temperature is then raised to 140-160°C, vacuumed, and the reaction is continued for 1-4 hours while stirring to obtain aminovinyl silicone oil.

[0013] Preferably, the aminovinyl silicone oil is prepared by the following method:

[0014] After nitrogen is introduced into the container, tetramethylammonium hydroxide catalyst and D4 (octamethylcyclotetrasiloxane), vinyltrichlorosilane are added, and the mixture is heated to 120°C while stirring. After reacting for 8 hours for hydrolysis and chain extension, aminopropyltrimethoxysilane, tetramethyldivinylsiloxane or hexamethyldisilazane end-capping agent is added, and the reaction is continued for 8 hours. The temperature is then raised to 150°C, vacuumed, and the reaction is continued for 2 hours while stirring to obtain aminovinyl silicone oil.

[0015] Preferably, the hydrogenated silicone oil is a linear polymer, and the structural formula is as follows:

[0016]

[0017] Wherein a and b are the polymerization degrees of the repeating units; R1 is an alkyl group with 1 to 8 carbon atoms; R2 is a methyl group or an H group; R3 is a methyl group or an H group; and the mass content of hydrogen groups in the hydrogen-containing silicone oil is 0.01% to 1.6%.

[0018] Preferably, the vinyl MQ silicone resin is a bulk polymer with the molecular formula [(CH2=CH)(CH3)2Si0 1 / 2 ] a [Si0 4 / 2 ] b , wherein a is the molar amount of the M unit, b is the molar amount of the Q unit, the MQ ratio range is 0.6-0.9, and the weight average molecular weight Mw is 3000-10000.

[0019] Preferably, the methyl MQ silicone resin is a bulk polymer with the molecular formula [(CH3)3Si0 1 / 2 ] a [Si0 4 / 2 ]b , wherein a is the molar amount of the M unit, b is the molar amount of the Q unit, the MQ ratio range is 0.6-0.9, and the weight average molecular weight Mw is 3000-10000.

[0020] Preferably, the catalyst is a platinum catalyst with a platinum content of 3000-5000 ppm;

[0021] The inhibitor is butynol;

[0022] The solvent is toluene.

[0023] A second aspect of the present invention provides a method for preparing the low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive as described above, comprising the following steps:

[0024] Step 1: Weigh the raw materials according to weight ratio;

[0025] Step 2: Add the solvent, methyl MQ silicone resin, and vinyl MQ silicone resin into the container in sequence, and stir at 500-1000 rpm until completely dissolved;

[0026] Step 3: Add amino vinyl silicone oil, hydrogen silicone oil, and inhibitor, and stir at 500-1000 rpm for 5-10 minutes;

[0027] Step 4: Add catalyst and stir at 500-1000 rpm for 10-15 minutes;

[0028] Step 6: Pass through a 400-mesh filter;

[0029] Step 7: The obtained filtrate is coated by a coating process and vulcanized at 100-120° C. for 3-8 minutes to obtain a low glass transition temperature, high modulus and high viscosity silicone pressure-sensitive adhesive.

[0030] The beneficial effects of the present invention are:

[0031] The present invention provides a low-glass-transition-temperature, high-modulus, high-viscosity organosilicon pressure-sensitive adhesive, which has a low tg while also having a high storage modulus, a high elastic modulus, and high viscosity. The high storage modulus improves its hardness, making it suitable for high-hardness use scenarios. The high elastic modulus can improve its cohesion and mechanical strength, making it more resilient and rigid. The high viscosity can improve the adhesion to common substrates and better achieve adhesion. The organosilicon pressure-sensitive adhesive of the present invention breaks the technical bottleneck of conventional organosilicon pressure-sensitive adhesives with low glass transition temperature, low modulus, low viscosity or high glass transition temperature, high modulus, and high viscosity, and expands the application scenarios of organosilicon pressure-sensitive adhesives.

[0032] Conventional silicone pressure-sensitive adhesives can increase their modulus and viscosity by using methyl MQ resins, but their shortcoming is that the more methyl MQ resin is added, the higher the glass transition temperature will be. Adding reactive vinyl MQ resins can increase their modulus while maintaining a low glass transition temperature, but vinyl MQ resins do not significantly improve viscosity. In the present invention, by additionally adding amino vinyl silicone oil, strongly polar amino groups can be introduced into the side chains, solving the problem of having only weakly polar methyl groups in the side chains, thereby significantly improving their adhesion.

[0033] The preparation method of the present invention is simple to operate, is conducive to industrial production and promotion, and has broad application prospects. DETAILED DESCRIPTION

[0034] The present invention is further described in detail below with reference to the embodiments so that those skilled in the art can implement the invention with reference to the description.

[0035] It should be understood that terms such as “having”, “including” and “comprising” used herein do not preclude the existence or addition of one or more other elements or combinations thereof.

[0036] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Materials and reagents used in the following examples are commercially available unless otherwise specified. In the following examples, where specific conditions are not specified, the experiments were conducted under conventional conditions or those recommended by the manufacturer. Reagents and instruments used, where the manufacturer is not specified, are commercially available conventional products.

[0037] The invention provides a low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive and a preparation method thereof. The preparation raw materials comprise the following components in parts by weight: 90-150 parts of amino vinyl silicone oil, 1.5-15 parts of hydrogenated silicone oil, 90-150 parts of vinyl MQ silicone resin, 10-30 parts of methyl MQ silicone resin, 1-5 parts of catalyst, 1-5 parts of inhibitor and 50-100 parts of solvent.

[0038] In a preferred embodiment, the aminovinyl silicone oil is a linear polymer with the structural formula shown below:

[0039]

[0040] Wherein a, b, and c are the polymerization degrees of the repeating units; R1 is an alkyl group having 1 to 8 carbon atoms; R2 is a methyl group or a vinyl group; R3 is a methyl group or a vinyl group; and R4 is an amino group.

[0041] In a preferred embodiment, the mass content of vinyl groups in the aminovinyl silicone oil is 0.05%-1.6%, and the mass content of amino groups is 0.08%-0.25%.

[0042] In a preferred embodiment, aminovinyl silicone oil is prepared by the following method:

[0043] After nitrogen is introduced into the container, tetramethylammonium hydroxide catalyst and D4 (octamethylcyclotetrasiloxane), vinyltrichlorosilane are added, and the mixture is heated to 110-130°C while stirring. After reacting for 4-16 hours for hydrolysis and chain extension, aminopropyltrimethoxysilane, tetramethyldivinylsiloxane or hexamethyldisilazane end-capping agent is added, and the reaction is continued for 4-16 hours. The temperature is then raised to 140-160°C, vacuumed, and the reaction is continued for 1-4 hours while stirring to obtain aminovinyl silicone oil.

[0044] In a preferred embodiment, aminovinyl silicone oil is prepared by the following method:

[0045] After nitrogen is introduced into the container, tetramethylammonium hydroxide catalyst and D4 (octamethylcyclotetrasiloxane), vinyltrichlorosilane are added, and the mixture is heated to 120°C while stirring. After reacting for 8 hours for hydrolysis and chain extension, aminopropyltrimethoxysilane, tetramethyldivinylsiloxane or hexamethyldisilazane end-capping agent is added, and the reaction is continued for 8 hours. The temperature is then raised to 150°C, vacuumed, and the reaction is continued for 2 hours while stirring to obtain aminovinyl silicone oil.

[0046] In a preferred embodiment, the hydrogenated silicone oil is a linear polymer having the following structural formula:

[0047]

[0048] Wherein a and b are the polymerization degrees of the repeating units; R1 is an alkyl group with 1 to 8 carbon atoms, more preferably 1 carbon atom; R2 is a methyl group or an H group; R3 is a methyl group or an H group; the mass content of hydrogen groups in the hydrogen-containing silicone oil is 0.01%-1.6%.

[0049] In a preferred embodiment, the vinyl MQ silicone resin is a bulk polymer with the molecular formula [(CH2=CH)(CH3)2Si0 1 / 2 ] a [Si0 4 / 2 ] b , wherein a is the molar amount of the M unit, b is the molar amount of the Q unit, the MQ ratio range is 0.6-0.9, and the weight average molecular weight Mw is 3000-10000.

[0050] In a preferred embodiment, the methyl MQ silicone resin is a bulk polymer with the molecular formula [(CH3)3Si0 1 / 2 ] a [Si0 4 / 2 ] b, wherein a is the molar amount of the M unit, b is the molar amount of the Q unit, the MQ ratio range is 0.6-0.9, and the weight average molecular weight Mw is 3000-10000.

[0051] In a preferred embodiment, the catalyst is a platinum catalyst with a platinum content of 3000-5000 ppm.

[0052] In a preferred embodiment, the inhibitor is butynol.

[0053] The present invention also provides a method for preparing the above-mentioned low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive, comprising the following steps:

[0054] Step 1: Weigh the raw materials according to weight ratio;

[0055] Step 2: Add the solvent, methyl MQ silicone resin, and vinyl MQ silicone resin into the container in sequence, and stir at 500-1000 rpm until completely dissolved;

[0056] Step 3: Add amino vinyl silicone oil, hydrogen silicone oil, and inhibitor, and stir at 500-1000 rpm for 5-10 minutes;

[0057] Step 4: Add catalyst and stir at 500-1000 rpm for 10-15 minutes;

[0058] Step 6: Pass through a 400-mesh filter;

[0059] Step 7: The obtained filtrate is coated by a coating process and vulcanized at 100-120° C. for 3-8 minutes to obtain a low glass transition temperature, high modulus and high viscosity silicone pressure-sensitive adhesive.

[0060] The above is the overall concept of the present invention. Detailed embodiments and comparative examples are provided below to further illustrate the present invention.

[0061] The sources of the raw materials of the following examples and comparative examples are as follows:

[0062] (A) Amino vinyl silicone oil

[0063] code name Manufacturer <![CDATA[NH3 content wt%]]> Vi content wt% Does the side chain contain Vi? terminal group A1 self made 0.08 0.05 no Vi A2 self made 0.15 0.27 yes Me A3 self made 0.25 1.5 yes Vi

[0064] The preparation method of amino vinyl silicone oil A1 is:

[0065] After nitrogen is introduced into the container, 0.5 parts of tetramethylammonium hydroxide catalyst and 100 parts of D4 (octamethylcyclotetrasiloxane) are added by weight, and the mixture is heated to 120°C while stirring. After reacting for 8 hours for hydrolysis and chain extension, 3 parts of aminopropyltrimethoxysilane and 2 parts of tetramethyldivinylsiloxane end-capping agents are added. After continuing the reaction for 8 hours, the temperature is raised to 150°C, vacuumed, and the mixture is continued to react for 2 hours while stirring to obtain aminovinyl silicone oil.

[0066] The preparation method of amino vinyl silicone oil A2 is:

[0067] After nitrogen is introduced into the container, 0.5 parts of tetramethylammonium hydroxide catalyst and 100 parts of D4 (octamethylcyclotetrasiloxane) and 5 parts of vinyltrichlorosilane are added by weight, and the mixture is heated to 120°C while stirring. After reacting for 8 hours for hydrolysis and chain extension, 5 parts of aminopropyltrimethoxysilane and 2 parts of hexamethyldisilazane end-capping agents are added. After continuing the reaction for 8 hours, the temperature is raised to 150°C, vacuumed, and the reaction is continued for 2 hours while stirring to obtain aminovinyl silicone oil.

[0068] The preparation method of amino vinyl silicone oil A3 is:

[0069] After nitrogen is introduced into the container, 0.5 parts of tetramethylammonium hydroxide catalyst, 100 parts of D4 (octamethylcyclotetrasiloxane), and 25 parts of vinyltrichlorosilane are added by weight, and the mixture is heated to 120°C while stirring. After reacting for 8 hours for hydrolysis and chain extension, 8 parts of aminopropyltrimethoxysilane and 2 parts of tetramethyldivinylsiloxane end-capping agents are added. After continuing the reaction for 8 hours, the temperature is raised to 150°C, vacuumed, and the mixture is continued to react for 2 hours while stirring to obtain aminovinyl silicone oil.

[0070] (B) Hydrogenated silicone oil

[0071] code name Manufacturer Brand H group content wt% Does the side chain contain H? terminal group B1 Runhe New Materials RH-DH01 0.01 no H B2 Runhe New Materials RH-H23 0.4 yes Me B3 Dow 7028 1.6 yes H

[0072] (C) Vinyl MQ silicone resin

[0073] code name Manufacturer Brand Molecular weight MQ ratio C1 Dayi Chemical DY-VMQ101 3500-4000 0.8 C2 New Four Seas SH-5202 4000-5500 0.85

[0074] (D) Methyl MQ silicone resin

[0075] code name Manufacturer Brand Molecular weight MQ ratio D1 Dayi Chemical DY-MQ102N 5000-6000 0.73 D2 New Four Seas SH-5201 3000-4000 0.82

[0076] Other additives

[0077] additives code name Manufacturer Brand catalyst E Dow Pt4000 inhibitors F Guangzhou Silicon Friends 1-Ethynylcyclohexanol

[0078] Examples 1-3 and Comparative Examples 1-3 provide silicone pressure-sensitive adhesives with different raw material ratios. The following are the specific ingredients (in parts by weight) of each example and comparative example:

[0079]

[0080]

[0081] The preparation methods of Examples 1-3 and Comparative Examples 1-3 are the same, and both include the following steps:

[0082] Step 1: Weigh the raw materials according to weight ratio;

[0083] Step 2: Add the solvent, methyl MQ silicone resin, and vinyl MQ silicone resin into the container in sequence, and stir at 700 rpm until the reactive resin is completely dissolved in the solvent;

[0084] Step 3: Add amino vinyl silicone oil (or regular vinyl silicone oil), hydrogen silicone oil, and inhibitor, and stir at 7000 rpm for 10 minutes;

[0085] Step 4: Add catalyst and stir at 700 rpm for 10 min;

[0086] Step 6: Pass through a 400-mesh filter;

[0087] Step 7: The obtained filtrate is coated using a coating process and vulcanized at 110° C. for 5 minutes to obtain a low glass transition temperature and high modulus silicone pressure-sensitive adhesive.

[0088] The following performance tests were performed on the silicone pressure-sensitive adhesives prepared in Examples 1-3 and Comparative Examples 1-3.

[0089] Sample test items are as follows:

[0090] Test items Test equipment Equipment brand and model Storage modulus / -20℃MPa TMA Mettler DMA1 Storage modulus / 25℃MPa TMA Mettler DMA1 Storage modulus / 60℃MPa TMA Mettler DMA1 Tg℃ TMA Mettler DMA1 Transmittance% Transmittance tester Shanghai Yidian WGT-S Haze % Transmittance tester Shanghai Yidian WGT-S Tensile strength MPa Universal tensile machine Instron 34SC-1 Elongation at break % Universal tensile machine Instron 34SC-1 Elastic modulus MPa Universal tensile machine Instron 34SC-1

[0091] The performance test results of Comparative Examples 1-3 and Comparative Examples 1-3 are as follows:

[0092]

[0093]

[0094] From the above test data, it can be clearly seen that the organic pressure-sensitive adhesives provided in Examples 1-3 are compatible with high modulus while ensuring low tg, and have more excellent cohesion and mechanical properties as well as high adhesion.

[0095] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and implementation methods. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to specific details.

Claims

1. A low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive and a preparation method thereof, characterized in that: The raw materials for its preparation include the following components by weight: 90-150 parts of amino vinyl silicone oil, 1.5-15 parts of hydrogenated silicone oil, 90-150 parts of vinyl MQ silicone resin, 10-30 parts of methyl MQ silicone resin, 1-5 parts of catalyst, 1-5 parts of inhibitor and 50-100 parts of solvent.

2. The low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive according to claim 1, characterized in that: The amino vinyl silicone oil is a linear polymer, and its structural formula is as follows: Wherein a, b, and c are the polymerization degrees of the repeating units; R1 is an alkyl group having 1 to 8 carbon atoms; R2 is a methyl group or a vinyl group; R3 is a methyl group or a vinyl group; and R4 is an amino group.

3. The low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive according to claim 2, characterized in that: The mass content of vinyl in the amino vinyl silicone oil is 0.05%-1.6%, and the mass content of amino is 0.08%-0.25%.

4. The low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive according to claim 3, characterized in that: The aminovinyl silicone oil is prepared by the following method: After nitrogen is introduced into the container, tetramethylammonium hydroxide catalyst, octamethylcyclotetrasiloxane, and vinyltrichlorosilane are added, and the mixture is heated to 110-130°C while stirring. After reacting for 4-16 hours for hydrolysis and chain extension, aminopropyltrimethoxysilane, tetramethyldivinylsiloxane, or hexamethyldisilazane end-capping agent is added, and the reaction is continued for 4-16 hours. The temperature is then raised to 140-160°C, vacuumed, and the reaction is continued for 1-4 hours while stirring to obtain aminovinyl silicone oil.

5. The low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive according to claim 4, characterized in that: The aminovinyl silicone oil is prepared by the following method: After nitrogen is introduced into the container, tetramethylammonium hydroxide catalyst, octamethylcyclotetrasiloxane, and vinyltrichlorosilane are added, and the mixture is heated to 120°C while stirring. After reacting for 8 hours for hydrolysis and chain extension, aminopropyltrimethoxysilane, tetramethyldivinylsiloxane or hexamethyldisilazane end-capping agent is added, and the reaction is continued for 8 hours. The temperature is then raised to 150°C, vacuumed, and the reaction is continued for 2 hours while stirring to obtain aminovinyl silicone oil.

6. The low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive according to claim 1, characterized in that: The hydrogenated silicone oil is a linear polymer, and its structural formula is as follows: Wherein a and b are the polymerization degrees of the repeating units; R1 is an alkyl group with 1 to 8 carbon atoms; R2 is a methyl group or an H group; R3 is a methyl group or an H group; and the mass content of hydrogen groups in the hydrogen-containing silicone oil is 0.01% to 1.6%.

7. The low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive according to claim 1, characterized in that: The vinyl MQ silicone resin is a bulk polymer with the molecular formula [(CH2=CH)(CH3)2Si0 1 / 2 ] a [Si0 4 / 2 ] b , wherein a is the molar amount of the M unit, b is the molar amount of the Q unit, the MQ ratio range is 0.6-0.9, and the weight average molecular weight Mw is 3000-10000.

8. The low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive according to claim 1, characterized in that: The methyl MQ silicone resin is a bulk polymer with the molecular formula [(CH3)3Si0 1 / 2 ] a [Si0 4 / 2 ] b , wherein a is the molar amount of the M unit, b is the molar amount of the Q unit, the MQ ratio range is 0.6-0.9, and the weight average molecular weight Mw is 3000-10000.

9. The low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive according to claim 1, characterized in that: The catalyst is a platinum catalyst with a platinum content of 3000-5000 ppm; the inhibitor is butynol; and the solvent is toluene.

10. A method for preparing a low glass transition temperature, high modulus and high viscosity organosilicon pressure-sensitive adhesive according to any one of claims 1 to 9, characterized in that: The steps include: Step 1: Weigh the raw materials according to weight ratio; Step 2: Add the solvent, methyl MQ silicone resin, and vinyl MQ silicone resin into the container in sequence, and stir at 500-1000 rpm until completely dissolved; Step 3: Add amino vinyl silicone oil, hydrogen silicone oil, and inhibitor, and stir at 500-1000 rpm for 5-10 minutes; Step 4: Add catalyst and stir at 500-1000 rpm for 10-15 minutes; Step 6: Pass through a 400-mesh filter; Step 7: The obtained filtrate is coated by a coating process and vulcanized at 100-120° C. for 3-8 minutes to obtain a low glass transition temperature, high modulus and high viscosity silicone pressure-sensitive adhesive.

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