Electron beam irradiation cross-linked organic silicon pressure-sensitive adhesive and preparation method thereof

Abstract

The invention discloses an electron beam irradiation cross-linked organic silicon pressure-sensitive adhesive and a preparation method thereof, and the organic silicon pressure-sensitive adhesive comprises the following raw material components by weight: 100 parts of vinyl silicone oil; 2-5 parts of a reactive organic silicon modifier; 10 to 15 parts of organic silicon resin; 10-30 parts of a composite heat-conducting filler; 5-20 parts of a phosphorus-nitrogen flame retardant; the reaction type organic silicon modifier is prepared from hydrogen-containing silicone oil grafted with an epoxy group-containing functional group and a phenolic hydroxyl group-containing functional group, and the molar ratio of the epoxy group-containing functional group to the phenolic hydroxyl group-containing functional group is 1: 2. Under the action of the reactive organic silicon modifier in the organic silicon pressure-sensitive adhesive, the filler can be uniformly dispersed in the matrix, so that the heat conductivity and flame retardance of the material are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure-sensitive adhesives, and particularly to an organosilicon pressure-sensitive adhesive crosslinked by electron beam irradiation and a preparation method thereof. Background Art

[0002] Organosilicon pressure-sensitive adhesives have excellent electrical insulation, high and low temperature resistance, weather resistance and other advantages, and are widely used in fields such as precision electronics, power equipment, aerospace, and new energy vehicle battery modules.

[0003] However, existing organosilicon pressure-sensitive adhesives still have many deficiencies. For example, volatile toxic organic solvents need to be added during the preparation process, which not only affects the physical health of production workers but also causes environmental pollution. Usually, organotin or amine catalysts are required for condensation reactions, or peroxides and platinum catalysts are required for crosslinking reactions, resulting in high production costs and complex processes. Organosilicon pressure-sensitive adhesives usually rely on thermal curing or platinum-catalyzed crosslinking, which requires high-temperature and long-time reactions, easily causing substrate deformation. Moreover, platinum catalysts are easily poisoned by the strong interaction of lone pair electrons on phosphorus, nitrogen, and sulfur atoms, making it impossible to use phosphorus-nitrogen-based flame retardants and difficult to achieve efficient halogen-free flame retardancy. The addition of a large amount of inorganic flame retardants and thermal conductive fillers will seriously deteriorate the adhesion performance of the pressure-sensitive adhesive due to the poor interfacial compatibility between the filler and the organosilicon molecular chain. The adhesion to low-surface-energy materials is poor, and debonding failure is likely to occur.

[0004] With the continuous development of fields such as electronic devices, higher requirements are also put forward for the flame retardancy and thermal conductivity of pressure-sensitive adhesives, and existing organosilicon pressure-sensitive adhesives still cannot meet the actual application requirements in these aspects. Summary of the Invention

[0005] The purpose of the present invention is to provide an organosilicon pressure-sensitive adhesive crosslinked by electron beam irradiation and a preparation method thereof for the problem that existing flame-retardant pressure-sensitive adhesives have poor adhesion to low-surface-energy materials and are prone to debonding failure in the prior art.

[0006] The technical solution adopted to achieve the purpose of the present invention is as follows:

[0007] In a first aspect, an organosilicon pressure-sensitive adhesive crosslinked by electron beam irradiation includes the following raw material components in parts by weight: vinyl silicone oil, 100 parts; reactive organosilicon modifier, 2 - 5 parts; organosilicon resin, 10 - 15 parts; composite thermal conductive filler 10 - 30 parts; phosphorus-nitrogen-based flame retardant 5 - 20 parts; the reactive organosilicon modifier is prepared by grafting hydrogen-containing silicone oil with epoxy group-functional and phenol hydroxyl group-functional groups, wherein the molar ratio of the epoxy group-functional and phenol hydroxyl group-functional groups is 1:(1.5 - 3).

[0008] The inventors found that when the epoxy groups grafted on the main chain of the hydrogen-containing silicone oil and the phenolic hydroxyl groups were controlled in terms of the molar ratio of the epoxy groups and the phenolic hydroxyl groups, one end of the reactive organosilicon modifier underwent a ring-opening reaction with the active groups on the surface of the organosilicon resin or the filler, forming stable chemical bonds; the polarity of the phenolic hydroxyl groups at the other end produced hydrogen bonds or van der Waals forces with the surfaces of the composite thermal conductive filler and the phosphorus-nitrogen-based flame retardant, reducing the surface energy of the filler, weakening the agglomeration tendency between the particles, and achieving a dynamic balance between the repulsive force and the attractive force between the filler particles, enabling them to be evenly distributed in the vinyl silicone oil matrix, avoiding the phenomenon of excessive or too low local concentration, significantly improving the uniformity of the material, and effectively enhancing the thermal conductivity and flame retardancy of the material.

[0009] In some specific embodiments, the composite thermal conductive filler includes alumina, boron nitride, and carbon nanotubes, and the mass ratio of alumina, boron nitride, and carbon nanotubes is (40 - 60):(10 - 20):(1 - 10).

[0010] In the above technical solution, when alumina, boron nitride, and carbon nanotubes are mixed in a mass ratio of (40 - 60):(10 - 20):(1 - 10), it can not only ensure that alumina and boron nitride construct a continuous thermal conductive framework, but also utilize the high aspect ratio characteristics of carbon nanotubes to form a three-dimensional thermal conductive network with an "point-line-plane" interweaving in the matrix. While improving the thermal conductivity, it effectively enhances the mechanical strength of the pressure-sensitive adhesive and effectively balances the mechanical properties and thermal conductivity requirements of the material.

[0011] In some specific embodiments, the alumina is spherical alumina with a particle size of 5 - 60 μm; and / or, the boron nitride is hexagonal boron nitride with a particle size of 0.05 - 1 μm; and / or, the carbon nanotubes are multi-walled carbon nanotubes with a length of 1 - 10 μm.

[0012] In the above technical solution, the 5 - 60 μm spherical alumina serves as the basis of the thermal conductive network, and the relatively large particle size forms a stable skeleton support in the matrix, reducing the sedimentation and agglomeration of the filler. The 0.05 - 1 μm nano-scale hexagonal boron nitride fills the micron-scale voids between the alumina particles, forming a "micron-nano" nested structure; the multi-walled carbon nanotubes with a length of 1 - 10 μm penetrate between the two, connecting the isolated filler particles to form a three-dimensional thermal conductive network. This precise matching of multi-level particle sizes enables the filler to form a continuous thermal conductive network without dead angles in the matrix, significantly reducing the interfacial thermal resistance in the heat conduction path.

[0013] In some specific embodiments, the structure of the reactive organosilicon modifier is as shown in Formula I.

[0014]

[0015] In Formula I, a is any integer from 4 to 8, n is any integer from 20 to 40, d is any integer from 2 to 4, and e is any integer from 2 to 8.

[0016] In some specific embodiments, the phosphorus-nitrogen based flame retardant is one or more of ammonium polyphosphate, resorcinol bis(diphenyl phosphate), and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0017] In some specific embodiments, the silicone resin is one or more of vinyl MQ silicone resin and hydrogen-containing MQ silicone resin.

[0018] In some specific embodiments, the silicone pressure-sensitive adhesive satisfies at least one of the following: (1) the flame retardancy of the silicone pressure-sensitive adhesive meets the UL94 V-0 grade; (2) the thermal conductivity of the silicone pressure-sensitive adhesive is 0.5 - 1.5 W / (m·K); (3) the peel strength of the silicone pressure-sensitive adhesive is ≥ 5 N / cm.

[0019] In the above specific embodiments, the silicone pressure-sensitive adhesive of the present application has excellent flame retardancy and peel strength, and is suitable for application scenarios with strict requirements for flame retardancy, thermal conductivity, and high temperature resistance, such as bonding in electronic appliances and new energy vehicle battery modules.

[0020] In a second aspect, a preparation method of the silicone pressure-sensitive adhesive of the first aspect includes the following steps: using a reactive silicone modifier to modify a composite thermal conductive filler to obtain a modified filler; mixing the modified filler, the phosphorus-nitrogen based flame retardant, and the silicone resin, adding vinyl silicone oil after dispersion to obtain a premix; coating the premix into a film and then initiating crosslinking and curing by electron beam irradiation to form a three-dimensional network structure to obtain the silicone pressure-sensitive adhesive.

[0021] The preparation method of the present application adopts the method of electron beam crosslinking, which is simple in operation, highly flexible, greatly shortens the production cycle, improves production efficiency, and is especially suitable for large-scale industrial production. Compared with the traditional thermal curing process, the present invention combines electron beam irradiation crosslinking with flame retardant and thermal conductive function design, avoiding problems such as high energy consumption and low efficiency of the traditional thermal curing process.

[0022] In some specific embodiments, in the step of using a reactive silicone modifier to modify a composite thermal conductive filler to obtain a modified filler, the modification treatment includes ball milling treatment, the rotation speed of the ball milling treatment is 150 - 500 r / min, and the time of the ball milling treatment is 1 - 5 h.

[0023] In the above specific embodiments, by adopting ball milling treatment and controlling the ball milling parameters at the same time, the surface of the filler can be uniformly coated with modifier molecules, significantly reducing the surface energy, effectively inhibiting the secondary aggregation of the filler in the subsequent mixing process, and improving the dispersion uniformity in the matrix.

[0024] In some specific embodiments, after the premix is coated into a film, it is irradiated with electron beam to induce crosslinking and curing to form a three-dimensional network structure to obtain an organosilicon pressure-sensitive adhesive, and the acceleration voltage of the electron beam irradiation is 100-150 kV, and the electron beam irradiation time is 1-5 seconds. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0026] In this specific embodiment, the reactive organosilicon modifier is synthesized by grafting with hydrogenated silicone oil as a raw material using a platinum catalyst according to the hydrosilylation method (addition reaction of a compound containing a silicon-hydrogen bond (Si-H) with an unsaturated hydrocarbon (such as an olefin, an alkyne) under the action of a catalyst). Alumina, hexagonal boron nitride and carbon nanotubes are purchased from Shanghai MacLean Biochemical Technology Co., Ltd., hydrogenated MQ silicone resin and vinyl MQ silicone resin are purchased from Guangzhou Siyou New Materials Technology Co., Ltd., 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is purchased from Shanghai Haohong Biomedicine Technology Co., Ltd., and vinyl silicone oil is purchased from Guangzhou Siyou New Materials Technology Co., Ltd.

[0027] Example 1

[0028] An electron beam irradiation cross-linked silicone pressure-sensitive adhesive is prepared by the following method:

[0029] S1, use 5g of a reactive silicone modifier containing epoxy groups and phenolic hydroxyl groups (a=9, n=40, d=3, e=2, and the specific structure is shown in Formula II) to modify 30g of a composite thermal conductive filler (60μm spherical alumina, 1μm hexagonal boron nitride and 1μm carbon nanotube in a mass ratio of 60:20:10) by ball milling (ball milling speed of 150r / min, ball milling time of 5h) to obtain a modified filler.

[0030]

[0031] S2, the modified filler prepared in S1, 15 g of vinyl MQ silicone resin and 5 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are added to 100 g of vinyl silicone oil after high-speed shear dispersion, and vacuum degassing is performed.

[0032] S3, after coating and film formation, irradiate with an electron beam at an accelerating voltage of 100 kV for 5 seconds to form a three-dimensional network structure to obtain an organic silicone pressure-sensitive adhesive.

[0033] Example 2

[0034] An organosilicon pressure-sensitive adhesive crosslinked by electron beam irradiation is prepared by the following method:

[0035] S1. Use 5 g of a reactive organosilicon modifier containing epoxy groups and phenolic hydroxyl groups (a = 6, n = 30, d = 3, e = 5, the specific structure is shown in Formula III) to modify 25 g of a composite thermal conductive filler (60 μm spherical alumina, 1 μm hexagonal boron nitride, and 5 μm carbon nanotubes with a mass ratio of 60:15:5) by ball milling (ball milling speed is 300 r / min, ball milling time is 3 h) to obtain a modified filler.

[0036]

[0037] S2. Add the modified filler prepared in S1, 15 g of hydrogen-containing MQ silicone resin, and 8 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to 100 g of vinyl silicone oil after high-speed shear dispersion, and perform vacuum degassing treatment.

[0038] S3. After coating into a film, irradiate it with an electron beam at an accelerating voltage of 150 kV for 1 second to form a three-dimensional network structure, and obtain the organosilicon pressure-sensitive adhesive.

[0039] Example 3

[0040] An organosilicon pressure-sensitive adhesive crosslinked by electron beam irradiation is prepared by the following method:

[0041] S1. Use 4 g of a reactive organosilicon modifier containing epoxy groups and phenolic hydroxyl groups (a = 3, n = 20, d = 2, e = 9, the specific structure is shown in Formula IV) to modify 20 g of a composite thermal conductive filler (60 μm spherical alumina, 1 μm hexagonal boron nitride, and 10 μm carbon nanotubes with a mass ratio of 60:20:10) by ball milling (ball milling speed is 500 r / min, ball milling time is 1 h) to obtain a modified filler.

[0042]

[0043] S2. Add the modified filler prepared in S1, 12 g of vinyl MQ silicone resin, and 10 g of resorcinol bis(diphenyl phosphate) to 100 g of vinyl silicone oil after high-speed shear dispersion, and perform vacuum degassing treatment.

[0044] S3. After coating into a film, irradiate it with an electron beam at an accelerating voltage of 120 kV for 3 seconds to form a three-dimensional network structure, and obtain the organosilicon pressure-sensitive adhesive.

[0045] Example 4

[0046] An organosilicon pressure-sensitive adhesive crosslinked by electron beam irradiation is prepared by the following method:

[0047] S1. Use 4 g of a reactive silicone modifier containing epoxy groups and phenolic hydroxyl groups (a = 9, n = 40, d = 3, e = 2, specific structure shown in Formula II) to modify 15 g of composite thermal conductive filler (30 μm spherical alumina, 0.1 μm hexagonal boron nitride, and 1 μm carbon nanotubes with a mass ratio of 40:20:5) by ball milling (ball milling speed is 400 r / min, ball milling time is 2 h) to obtain a modified filler.

[0048] S2. Add the modified filler prepared in S1, 12 g of vinyl MQ silicone resin, and 20 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide into 100 g of vinyl silicone oil after high-speed shear dispersion, and perform vacuum degassing treatment.

[0049] S3. After coating into a film, irradiate it with an electron beam at an accelerating voltage of 100 kV for 5 s to form a three-dimensional network structure and obtain an organosilicon pressure-sensitive adhesive.

[0050] Example 5

[0051] An organosilicon pressure-sensitive adhesive crosslinked by electron beam irradiation is prepared by the following method:

[0052] S1. Use 2 g of a reactive silicone modifier containing epoxy groups and phenolic hydroxyl groups (a = 6, n = 30, d = 3, e = 5, specific structure shown in Formula III) to modify 10 g of composite thermal conductive filler (30 μm spherical alumina, 0.1 μm hexagonal boron nitride, and 1 μm carbon nanotubes with a mass ratio of 50:20:10) by ball milling (ball milling speed is 150 r / min, ball milling time is 5 h) to obtain a modified filler.

[0053] S2. Add the modified filler prepared in S1, 10 g of vinyl MQ silicone resin, and 20 g of ammonium polyphosphate into 100 g of vinyl silicone oil after high-speed shear dispersion, and perform vacuum degassing treatment.

[0054] S3. After coating into a film, irradiate it with an electron beam at an accelerating voltage of 120 kV for 3 s to form a three-dimensional network structure and obtain an organosilicon pressure-sensitive adhesive.

[0055] Comparative Example 1

[0056] A pressure-sensitive adhesive is prepared by the following method:

[0057] S1. Mix 15 g of vinyl MQ silicone resin with 5 g of a reactive silicone modifier containing epoxy groups and phenolic hydroxyl groups (a = 9, n = 40, d = 3, e = 2, specific structure shown in Formula II), and add it into 100 g of vinyl silicone oil after high-speed shear dispersion.

[0058] S2. Add 5 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and perform vacuum degassing treatment.

[0059] S3. After coating and forming a film, irradiate it with an electron beam at an accelerating voltage of 100 kV for 5 seconds to obtain the pressure-sensitive adhesive.

[0060] Comparative Example 2

[0061] A pressure-sensitive adhesive is prepared by the following method:

[0062] S1. After treating 30 g of 60-μm spherical alumina, 1-μm hexagonal boron nitride, and 1-μm carbon nanotubes with a mass ratio of 60:20:10 by ball milling (ball milling speed is 150 r / min, ball milling time is 5 h), mix it with 15 g of vinyl MQ silicone resin, and add it to 100 g of vinyl silicone oil after high-speed shear dispersion.

[0063] S2. Add 5 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and perform vacuum degassing treatment.

[0064] S3. After coating and forming a film, irradiate it with an electron beam at an accelerating voltage of 100 kV for 5 seconds to obtain the pressure-sensitive adhesive.

[0065] Comparative Example 3

[0066] A pressure-sensitive adhesive is prepared by the following method:

[0067] S1. Use 5 g of a reactive silicone modifier containing epoxy groups and phenolic hydroxyl groups (a = 9, n = 40, d = 3, e = 2, specific structure is shown in Formula II) to treat and modify 30 g of composite thermal conductive filler (60-μm spherical alumina, 1-μm hexagonal boron nitride, and 1-μm carbon nanotubes with a mass ratio of 60:20:10) by ball milling (ball milling speed is 150 r / min, ball milling time is 5 h) to obtain the modified filler.

[0068] S2. Add the modified filler prepared in S1, 15 g of vinyl MQ silicone resin, 5 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 4 g of hydrogen-containing silicone oil (hydrogen content is 1.2 wt%), and 0.1 g of Karstedt's organoplatinum catalyst (platinum content is 3000 ppm), and add it to 100 g of vinyl silicone oil after high-speed shear dispersion, and perform vacuum degassing treatment.

[0069] S3. Add and vulcanize at 130 °C for 20 min to obtain the pressure-sensitive adhesive.

[0070] Comparative Example 4

[0071] A pressure-sensitive adhesive is prepared by the following method:

[0072] S1. Use a reactive silicone modifier containing epoxy groups and phenolic hydroxyl groups (a = 9, n = 40, d = 3, e = 2, and the specific structure is shown in Formula II) with a mass of 5 g to treat and modify 30 g of composite thermal conductive filler (60 μm spherical alumina, 1 μm hexagonal boron nitride, and 1 μm carbon nanotubes with a mass ratio of 60:20:10) by ball milling (the ball milling speed is 150 r / min and the ball milling time is 5 h) to obtain the modified filler.

[0073] S2. Add the modified filler prepared in S1, 15 g of vinyl MQ silicone resin, 5 g of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 1 g of benzophenone (photoinitiator) into 100 g of vinyl silicone oil after high-speed shear dispersion, and perform vacuum degassing treatment.

[0074] S3. After coating and forming a film, irradiate it with ultraviolet light of 500 W for 1 min to obtain the pressure-sensitive adhesive.

[0075] Performance test:

[0076] Perform performance tests on the silicone pressure-sensitive adhesives of Examples 1 to 5 and the pressure-sensitive adhesives of Comparative Examples 1 to 4. The test methods are as follows:

[0077] Adhesion performance test: According to the test standard of GB / T 2792-2014, measure the peel strength of the specimen. Thermal conductivity test: Use Hotdisk TP2500S, single-sided method test module, to measure the thermal conductivity of the specimen. Flame retardancy test: According to the UL94 standard, measure the flame retardancy grade of the specimen.

[0078] The test results are shown in Table 1 and Table 2.

[0079] Table 1 shows the peel strength test results of Examples 1 to 5 and Comparative Examples 1 to 4

[0080] Group Thermal Conductive Filler / g Vinyl Silicone Oil / g Reactive Organosilicon Modifier / g Peel Strength / N / cm Example 1 30 100 5 5.4 Example 2 25 100 5 5.6 Example 3 20 100 4 5.9 Example 4 15 100 3 6.3 Example 5 10 100 2 6.1 Comparative Example 1 0 100 5 6.0 Comparative Example 2 30 100 0 4.7 Comparative Example 3 30 100 5 5.1 Comparative Example 4 30 100 5 5.2

[0081] Table 2 shows the thermal conductivity test results and flame retardancy grades of Examples 1 to 5 and Comparative Examples 1 to 4

[0082]

[0083]

[0084] It can be seen from Table 1 that with the increase of the filling amount of the filler, the peel strength of the silicone pressure-sensitive adhesive shows a trend of first increasing and then decreasing. Using a reactive silicone modifier to modify the composite filler, the silicone pressure-sensitive adhesives of Examples 1 - 5 show excellent peel strength (≥5 N / cm). Example 1 prepared by electron beam irradiation cross-linking shows better adhesion performance than Comparative Example 3 prepared by traditional thermal cross-linking and Comparative Example 4 prepared by UV cross-linking.

[0085] As can be seen from Table 2, with the increase in the filling amount of the filler, the thermal conductivity of the specimen gradually increases. Comparing Examples 1-5 with Comparative Example 1, when the thermal conductive filler is added, the thermal conductivity is significantly improved. The thermal conductivity of the blank sample in Comparative Example 1 is 0.2 W / (m·K). After adding the modified filler in Examples 1-5, the thermal conductivity is increased to between 0.5-1.5 W / (m·K), and the flame retardant grade reaches UL94 V0 level. Comparing Example 1 with Comparative Example 2, the thermal conductivity of Comparative Example 2 without using the reactive silicone modifier is only 0.9 W / (m·K), while the thermal conductivity of Example 1 can reach 1.5 W / (m·K). Using the reactive silicone modifier can effectively improve the thermal conductivity of the specimen. Comparing Example 1 with Comparative Examples 3-4, the silicone pressure-sensitive adhesive prepared by electron beam irradiation cross-linking has a higher thermal conductivity than the pressure-sensitive adhesives prepared by traditional thermal cross-linking and UV cross-linking methods.

[0086] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. An electron beam irradiated crosslinked silicone pressure sensitive adhesive, characterized in that, It includes raw material components in the following parts by weight: Vinyl silicone oil, 100 parts; Reactive silicone modifier, 2 - 5 parts; Silicone resin, 10 - 15 parts; Composite thermal conductive filler, 10 - 30 parts; Phosphorus - nitrogen - based flame retardant, 5 - 20 parts; The reactive silicone modifier is prepared by grafting hydrogen - containing silicone oil with epoxy - group - containing functional groups and phenolic - hydroxyl - group - containing functional groups, wherein the molar ratio of the epoxy - group - containing functional groups to the phenolic - hydroxyl - group - containing functional groups is 1:(1.5 - 3).

2. The silicone pressure-sensitive adhesive according to claim 1, wherein The composite thermal conductive filler includes alumina, boron nitride and carbon nanotubes, and the mass ratio of the alumina, the boron nitride and the carbon nanotubes is (40 - 60):(10 - 20):(1 - 10).

3. The silicone pressure-sensitive adhesive according to claim 2, wherein The alumina is spherical alumina with a particle size of 5 - 60 μm; And / or, the boron nitride is hexagonal boron nitride with a particle size of 0.05 - 1 μm; And / or, the carbon nanotubes are multi - walled carbon nanotubes with a length of 1 - 10 μm.

4. The silicone pressure-sensitive adhesive according to claim 1, wherein The structure of the reactive silicone modifier is shown in Formula I, In Formula I, a is any integer from 4 to 8, n is any integer from 20 to 40, d is any integer from 2 to 4, and e is any integer from 2 to 8.

5. The silicone pressure-sensitive adhesive according to claim 1, wherein The phosphorus - nitrogen - based flame retardant is one or more of ammonium polyphosphate, resorcinol bis(diphenyl phosphate) and 9,10 - dihydro - 9 - oxa - 10 - phosphaphenanthrene - 10 - oxide.

6. The silicone pressure-sensitive adhesive according to claim 1, characterized in that, The silicone resin is one or more of vinyl MQ silicone resin and hydrogen - containing MQ silicone resin.

7. The silicone pressure-sensitive adhesive according to claim 1, wherein The silicone pressure - sensitive adhesive satisfies at least one of the following: (1) The flame retardancy of the silicone pressure - sensitive adhesive meets UL94 V - 0 level; (2) The thermal conductivity of the silicone pressure - sensitive adhesive is 0.5 - 1.5 W / (m·K); (3) The peel strength of the silicone pressure - sensitive adhesive is ≥5 N / cm.

8. A method for preparing a silicone pressure-sensitive adhesive according to any one of claims 1-7, characterized in that, It includes the following steps: Using the reactive silicone modifier to modify the composite thermal conductive filler to obtain a modified filler; Mixing the modified filler, the phosphorus - nitrogen - based flame retardant and the silicone resin, dispersing them and then adding the vinyl silicone oil to obtain a premix; Coating the premix into a film and then initiating cross - linking curing by electron beam irradiation to form a three - dimensional network structure to obtain the silicone pressure - sensitive adhesive.

9. The preparation method according to claim 1, characterized in that, In the step of using the reactive silicone modifier to modify the composite thermal conductive filler to obtain a modified filler, the modification treatment includes ball - milling treatment, the rotation speed of the ball - milling treatment is 150 - 500 r / min, and the time of the ball - milling treatment is 1 - 5 h.

10. The preparation method according to claim 1, characterized in that, In the step of coating the premix into a film and then initiating cross - linking curing by electron beam irradiation to form a three - dimensional network structure to obtain the silicone pressure - sensitive adhesive, the accelerating voltage of the electron beam irradiation is 100 - 150 kV, and the time of the electron beam irradiation is 1 - 5 seconds.

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