Thixotropic liquid silicone rubber base rubber and preparation method thereof

Abstract

The invention relates to thixotropic liquid silicone rubber base rubber and a preparation method thereof. Comprising the following raw materials: vinyl silicone oil, white carbon black, modified cellulose and a coupling agent. The coupling agent is prepared from hexamethyl disilazane, dimethyl diethoxy silane and hydroxyl silicone oil, and the weight ratio of the hexamethyl disilazane to the dimethyl diethoxy silane to the hydroxyl silicone oil is 1 to (1.5 to 0.5) to (0.05 to 0.1). The liquid silicone rubber further comprises hydroxyl vinyl silicone oil, the content of the hydroxyl vinyl silicone oil is 0.01%-1%, and the viscosity of the hydroxyl vinyl silicone oil is 10 mPa.s to 10000 mPa.s. Under the joint cooperation of hexamethyldisilazane, dimethyldiethoxysilane and hydroxyl silicone oil, the dispersion of white carbon black in vinyl silicone oil is further promoted, the viscosity of the liquid silicone rubber during low shear is increased, and the thixotropic liquid silicone rubber with excellent performance is obtained. Cellulose is introduced into a silicone rubber system, and during standing, a rigid cellulose network and a white carbon black network are mutually interspersed and have synergistic interaction, so that the structural strength of the system is greatly enhanced.

Description

Technical Field

[0001] This invention belongs to the field of rubber processing technology, specifically relating to a highly thixotropic liquid silicone rubber and its preparation method. Background Technology

[0002] With societal development, people have increasingly higher demands for the environmental friendliness of their clothing, shoes, socks, gloves, hats, and other garments. Simultaneously, the pursuit of aesthetics is also constantly evolving, making printing a top choice for clothing decoration. In the early 21st century, some manufacturers used non-toxic and environmentally friendly silicone as a printing material on clothing, achieving unexpected results. Liquid silicone rubber, as a printing material, has gradually gained market popularity due to its adjustable viscosity and fluidity, excellent surface gloss, strong three-dimensional effect, and rapid thickness formation.

[0003] Currently, the most common method in the market is to transfer liquid silicone rubber patterns onto a substrate using screen printing. The thixotropic properties of this liquid silicone rubber are crucial to printing quality and efficiency. Poor thixotropy in liquid silicone rubber can directly lead to a series of problems, including decreased printing accuracy, pattern distortion, difficulty in color registration, and weak three-dimensionality.

[0004] Applications with extremely stringent requirements for thixotropy, such as ultra-fine screen printing (line width < 0.3 mm) or thick vertical coating without sagging, not only pursue a high thixotropic index (TI), but also pay attention to instantaneous recovery capability.

[0005] Therefore, the thixotropic properties of liquid silicone rubber need further improvement. Summary of the Invention

[0006] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, one object of this invention is to provide a highly thixotropic liquid silicone rubber and a method for preparing the same, wherein the liquid silicone rubber exhibits high thixotropy.

[0007] In a first aspect, the present invention provides a thixotropic liquid silicone rubber base, comprising vinyl silicone oil, silica, polyethylene glycol mono-, p-tert-octylphenyl ether modified cellulose, and a coupling agent. By mass fraction, the vinyl silicone oil content is 30-90%, the silica content is 10-50%, the coupling agent content is 0.1-10%, and the polyethylene glycol mono-, p-tert-octylphenyl ether modified cellulose content is 5-25%. According to the thixotropic liquid silicone rubber of the present invention, the thixotropic index of the liquid silicone rubber is increased through the interaction of the components, thus obtaining a liquid silicone rubber base with high thixotropic properties.

[0008] In another specific embodiment of the liquid silicone rubber according to the present invention, the silica is fumed silica, preferably with a specific surface area of ​​100-400 m². 2 / g, and more preferably, the specific surface area of ​​the fumed silica is 200-350m² / g. 2 / g. This significantly improves the thixotropic properties of liquid silicone rubber.

[0009] In another specific embodiment of the liquid silicone rubber according to the present invention, the content of silica in the liquid silicone rubber is 10-50%, such as 10-40%, 20-40%, 20-30%, etc. Preferably, the content of silica is 20-30%, such as 20-25%, 25-28%, 27-29%. Within the above content range, the thixotropic index of the material can be greatly improved while maintaining a suitable viscosity.

[0010] In another specific embodiment of the liquid silicone rubber according to the present invention, the coupling agent comprises hexamethyldisilazane (HDMS), dimethyldiethoxysilane (DMDES), and hydroxyl silicone oil, wherein HDMS, DMDES, and hydroxyl silicone oil are mixed in a weight ratio of 1:(0.5-15):(0.05-0.1). The hydroxyl content of the hydroxyl silicone oil is 0.1-10%, preferably 4%.

[0011] According to another specific embodiment of the liquid silicone rubber of the present invention, the content of the coupling agent in the liquid silicone rubber is 0.1-10%, such as 0.2-10%, 0.9-10%, 0.9-8%, 0.1-8%, etc. In a more preferred embodiment, the weight ratio of HDMS, DMDES, and hydroxyl silicone oil in the coupling agent is 1:(0.1-10)(0.01-1), which can increase the viscosity of the material at low shear and greatly improve the thixotropic index of the material.

[0012] According to another specific embodiment of the liquid silicone rubber of the present invention, the liquid silicone rubber further includes hydroxyl vinyl silicone oil, the content of which is 0.01-1% and the viscosity is 10-10000 mPa·s, preferably 100-1000 mPa·s. In a more preferred embodiment, the hydroxyl content of the hydroxyl vinyl silicone oil is 1-10%, and the vinyl content is 1-30%. By introducing hydroxyl vinyl silicone oil into the liquid silicone rubber through the above technical solution, the thixotropic properties of the liquid silicone rubber are enhanced, and the crosslinking density is increased, thereby improving its resistance to tearing forces.

[0013] In another specific embodiment of the liquid silicone rubber according to the present invention, the vinyl silicone oil is a commonly used type in the art, and the vinyl content is 30-90%, such as 30-80%, 40-90%, 50-70%, etc. Preferably, the vinyl silicone oil content is 50-70%. The vinyl silicone oil has a viscosity of 1000-100000 mPa·s at 25°C, preferably 5000-50000 mPa·s; the vinyl content of the vinyl silicone oil is 0.025-1.5%, preferably 0.04-0.4%. This is advantageous for obtaining a liquid silicone rubber with high thixotropic index and tear resistance.

[0014] In another specific embodiment of the liquid silicone rubber according to the present invention, the cellulose is one or more of cellulose nanocrystals (CNC), cellulose nanofibers (CNF), and bacterial cellulose (BC), preferably cellulose nanocrystals (CNC). This allows the silicone rubber to maintain its strength, form a dual thixotropic mechanism with silica, and increase its viscosity at low shear.

[0015] The modified cellulose was added by the following method: cellulose nanoparticles were dispersed in anhydrous ethanol, polyethylene glycol mono-p-tert-octylphenyl ether was added, and the mixture was stirred at 45-60°C and 100-200 rpm to carry out a surface grafting modification reaction. After the reaction was completed, the mixture was separated and dried to obtain the modified cellulose nanoparticle composite. The amount of polyethylene glycol mono-p-tert-octylphenyl ether was 5%-50% of the mass of the cellulose nanoparticles.

[0016] The nanocellulose is selected from at least one of cellulose nanocrystals (CNC), cellulose nanofibers (CNF), and bacterial cellulose (BC), with an average diameter of 5-50 nm and an average length of 100-500 nm. The molecular weight of polyethylene glycol mono-p-tert-octylphenyl ether is 400-2000.

[0017] This invention does not simply involve physically mixing cellulose and polyethylene glycol (PEG). Instead, it employs PEG mono-(p-tert-octylphenyl) ether, which has an amphiphilic structure, to pre-modify nanocellulose. One end of the modifier, a PEG segment, is anchored to the cellulose surface through grafting, while the other end, p-tert-octylphenyl ether, is a strongly hydrophobic group. When added to a silicone oil system, the hydrophobic end exhibits good compatibility with vinyl silicone oil, while the surface properties of the modified cellulose undergo a fundamental change, transforming from hydrophilic to having moderate compatibility with the silicone oil matrix. This solves the problem of unmodified cellulose easily agglomerating in silicone oil, achieving uniform dispersion at the nanoscale. During static standing, the rigid cellulose network and the silica network interpenetrate and synergistically enhance each other, significantly increasing the structural strength of the system (high static viscosity). Under shear stress, the flexible PEG chains on the cellulose surface first untangle and orient, leading to rapid dissociation of the entire network and a sharp decrease in viscosity, resulting in excellent workability. After shearing stops, the entropy-driven retraction and re-entanglement of the flexible polyethylene glycol chains can rapidly guide the reconstruction of the rigid network, achieving rapid thixotropic recovery on a second or even sub-second scale.

[0018] The liquid silicone rubber base provided by this invention exhibits improvements in thixotropic index (TI), anti-sagging properties (especially for thick coatings on vertical surfaces), and the ability to maintain fine lines in screen printing (clear line width ≤0.2mm). Simultaneously, due to the reinforcing effect of nanocellulose, the mechanical strength (tensile strength, tear strength) of the cured film is enhanced.

[0019] Secondly, the present invention provides a method for preparing thixotropic liquid silicone rubber. Step 1): Mix silica, 0.5-5 times the weight of silica in vinyl silicone oil, and coupling agent evenly at 50 to 100°C and maintain the mixture for 0.5 to 2 hours. Step 1): Continue heat treatment at 100 to 200°C under vacuum for 2 to 4 hours; Step 3): Add the remaining vinyl silicone oil and polyethylene glycol mono-p-tert-octylphenyl ether modified cellulose, and mix evenly under vacuum conditions (-0.1 MPa) to obtain thixotropic liquid silicone rubber.

[0020] The beneficial effects provided by this invention are as follows: 1. With the combined action of hexamethyldisilazane, dimethyldiethoxysilane, and hydroxyl silicone oil, the dispersion of silica in vinyl silicone oil was further promoted, and the viscosity of liquid silicone rubber at low shear was increased, resulting in a thixotropic liquid silicone rubber with excellent performance.

[0021] 2. Introducing cellulose into a silicone rubber system, when left to stand, allows the rigid cellulose network and the silica network to interpenetrate and synergistically enhance each other, significantly increasing the system's structural strength (high static viscosity), far superior to silica alone. Under shear stress, the flexible long chains on the cellulose surface first untangle and orient, leading to rapid dissociation of the entire network and a sharp decrease in viscosity, resulting in excellent workability. After shearing ceases, the entropy-driven retraction and reentanglement of the flexible long chains rapidly guide the reconstruction of the rigid network, achieving second-level or even sub-second-level fast contact.

[0022] 3. Introducing hydroxyl vinyl silicone oil into liquid silicone rubber can increase the chemical and physical crosslinking points of the liquid silicone rubber, thereby simultaneously improving the thixotropic properties and tear strength of the liquid silicone rubber.

[0023] 4. First, add some vinyl silicone oil and mix it with all the silica to increase the viscosity of the rubber compound and enhance the dispersion effect. Then, carry out a series of subsequent treatments to obtain liquid silicone rubber with good thixotropic and tear-resistant properties.

[0024] 5. This invention does not simply involve physically mixing cellulose and polyethylene glycol (PEG), but rather pre-modifies nanocellulose using PEG octylphenyl ether, which has an amphiphilic structure. One end of the PEG segment is anchored to the cellulose surface through grafting, while the other end, tert-octylphenyl ether, is a strongly hydrophobic group. When added to a silicone oil system, the hydrophobic end exhibits good compatibility with vinyl silicone oil, while the surface properties of the modified cellulose undergo a fundamental change, transforming from hydrophilic to having moderate compatibility with the silicone oil matrix. This solves the problem of unmodified cellulose easily agglomerating in silicone oil, achieving uniform dispersion at the nanoscale. During static standing, the rigid cellulose network and the silica network interpenetrate and synergistically enhance the structural strength of the system. Under shear stress, the flexible PEG chains on the cellulose surface first untangle and orient, leading to rapid dissociation of the entire network and a sharp decrease in viscosity. After shearing ceases, the entropy-driven retraction and re-entanglement of the flexible PEG chains rapidly guides the reconstruction of the rigid network, achieving rapid thixotropic recovery.

[0025] 6. The liquid silicone rubber base provided by this invention improves thixotropic index (TI), anti-sagging properties (especially for thick coatings on vertical surfaces), and the ability to maintain fine lines in screen printing (clear line width ≤0.2mm). Simultaneously, due to the reinforcing effect of nanocellulose, the mechanical strength (tensile strength, tear strength) of the cured film is enhanced. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the embodiments.

[0027] Abbreviations: Hexamethyldisilazane (HDMS), Dimethyldiethoxysilane (DMDES).

[0028] Example 1 Composition: Vinyl silicone oil (viscosity 20000 mPa•s, vinyl content 0.08%): 871.2 kg; Hydrophilic fumed silica (specific surface area 200 m² / g): 420.9 kg; Coupling agent (total weight 92.5 kg, ratio HMDS : DMDES : 4% hydroxyl silicone oil = 1 : 0.5 : 0.15); Preparation method: Step 1: Mix silica, 378.8 kg (approximately 0.9 times the mass of silica), vinyl silicone oil, and coupling agent at 50°C for 0.5 hours.

[0029] Step 2: Heat to 150°C and perform vacuum (-0.095 MPa) heat treatment for 2 hours.

[0030] Step 3: Add the remaining 492.4 kg of vinyl silicone oil and mix thoroughly under vacuum. Heat to 150°C and heat-treat under vacuum (-0.095 MPa) for 2 hours.

[0031] Examples 2-5 A liquid silicone rubber differs from Example 1 in that some raw materials are selected differently and the amounts of various raw materials are different.

[0032] The preparation method differs from that of Example 1 in that the ratio of vinyl silicone oil to silica powder, the temperature, and the time are different in step 1); and the heat treatment temperature and time are different in step 2). See Table 1 for details.

[0033] Table 1

[0034] Example 6 Based on Example 1, an additional 4.2 kg of hydroxyl vinyl silicone oil (viscosity 510 mPa•s, hydroxyl content 4.2%, vinyl content 8.6%) was added in step 3.

[0035] Example 7 A liquid silicone rubber, which differs from Example 6 in that the hydroxyl vinyl silicone oil has a viscosity of 50 mPa•s, a hydroxyl content of 9.0%, and a vinyl content of 3.5%.

[0036] Example 8 A liquid silicone rubber, which differs from Example 6 in that the hydroxyl vinyl silicone oil has a viscosity of 5000 mPa•s, a hydroxyl content of 1.2%, and a vinyl content of 0.16%.

[0037] Example 9 Based on Example 6, the amount of silica was reduced to 400.9 kg, the total amount of vinyl silicone oil remained unchanged, and an additional 30 kg of polyethylene glycol mono-p-tert-octylphenyl ether modified cellulose nanocrystals were added. In step 3, the modified cellulose nanocrystals were added together with the remaining vinyl silicone oil and hydroxyvinyl silicone oil, and mixed uniformly under vacuum.

[0038] Cellulose nanocrystal modification: 30 kg of cellulose nanocrystals were surface-grafted with 9 kg of polyethylene glycol mono-p-tert-octylphenyl ether, using the method described above. PEG400 was used as the polyethylene glycol segment as the modifier.

[0039] The modification method is as follows: Nanocellulose is dispersed in anhydrous ethanol, and polyethylene glycol octylphenyl ether is added. The mixture is stirred at 100 rpm for 45 minutes at 45°C to carry out a surface grafting modification reaction. After the reaction is complete, the nanocellulose is separated and dried to obtain the modified nanocellulose composite. The amount of polyethylene glycol octylphenyl ether is 25% of the mass of the nanocellulose. The average diameter of the cellulose is 30 nm, and the average length is 200 nm. The molecular weight of polyethylene glycol mono-p-tert-octylphenyl ether is 400.

[0040] Example 10 A liquid silicone rubber, which differs from Example 9 in that the amount of silica used is 415.9 kg and the amount of modified polyethylene glycol octylphenyl ether modified cellulose nanocrystals added is 15 kg.

[0041] Example 11 A liquid silicone rubber, which differs from Example 9 in that it uses polyethylene glycol segments modified with PEG1500.

[0042] Comparative Example 1 A liquid silicone rubber, differing from Example 1 in that it does not use a coupling agent. All silicone oil is added in step 1, and step 3 is omitted. Composition: Vinyl silicone oil (viscosity 20000 mPa•s, vinyl content 0.08%): 871.2 kg Hydrophilic fumed silica (specific surface area 200 m² / g): 420.9 kg Preparation method: Step 1: Mix silica and vinyl silicone oil at <50℃ for 0.5 hours.

[0043] Step 2: Heat to 150°C and perform vacuum (-0.095 MPa) heat treatment for 2 hours. Comparative Example 2 A liquid silicone rubber, which differs from Example 1 in that hexamethyldisilazane is replaced with an equal amount of dimethyldiethoxysilane.

[0044] Comparative Example 3 A liquid silicone rubber, which differs from Example 1 in that dimethyldiethoxysilane is replaced with an equal amount of vinyltrimethoxysilane.

[0045] Comparative Example 4 A liquid silicone rubber, which differs from Example 1 in that hydroxysiloxane is replaced with an equal amount of hydroxyvinyl silicone oil.

[0046] Comparative Example 5 A liquid silicone rubber, which differs from Example 1 in that hexamethyldisilazane, dimethyldiethoxysilane, and hydroxyl silicone oil are in a weight ratio of 1:1:1, that is, hexamethyldisilazane is 30.8 kg, dimethyldiethoxysilane is 30.8 kg, and hydroxyl silicone oil is 30.9 kg.

[0047] Comparative Example 6 A liquid silicone rubber, Example 9 differs in that the polyethylene glycol octylphenyl ether modified cellulose nanocrystals are replaced with an equal mass of untreated ordinary cellulose nanocrystals.

[0048] Comparative Example 7 A liquid silicone rubber, Example 9, differs in that it does not contain cellulose nanocrystals, but instead contains an equal mass of polyethylene glycol (PEG400).

[0049] Comparative Example 8 A liquid silicone rubber, as described in Example 9, differs in that the cellulose nanocrystals are unmodified, and the silica, unmodified cellulose nanocrystals, and polyethylene glycol mono-p-tert-octylphenyl ether are physically blended.

[0050] Comparative Example 9 A liquid silicone rubber, Example 9 differs in that all raw materials, including modified cellulose nanocrystals, are added and mixed at once, omitting step 3.

[0051] Comparative Example 10 A liquid silicone rubber, which differs from Example 9 in that... In the cellulose nanocrystal modification, the modifier was: polyethylene glycol octylphenyl ether was replaced with the same mass of PEG400, and the rest was the same as in Example 9. Performance testing 1. Viscosity test: The viscosity of Examples 1-11, Comparative Examples 1-10 and commercially available liquid silicone rubber were tested in accordance with GB / T 22235-2008 "Determination of viscosity of liquid".

[0052] Thixotropic index: refers to the index of the coefficient of performance at a shear rate of 1 s². -1 Viscosity was measured and 10s -1 The ratio of the measured viscosity.

[0053] 2. Thixotropic recovery time: Examples 1-11, Comparative Examples 1-8, and commercially available liquid silicone rubber were tested using a three-stage thixotropic testing method with a rotational test. Thixotropic recovery time refers to the time required for the viscosity to recover to 90% of its initial value after a given shear rate has been stopped.

[0054] 3. Tear strength test: Examples 1-11, Comparative Examples 1-10 and commercially available liquid silicone rubber were tested in accordance with GB / T 529-2008 "Determination of tear strength of vulcanized rubber or thermoplastic rubber (trouser-shaped, right-angled and crescent-shaped specimens)".

[0055] The test data for Experiments 1 and 2 are detailed in Table 2. 4. Printing fineness test: In accordance with the screen printing process, 300 mesh screen is used for printing. The line width of Examples 1-11, Comparative Examples 1-9 and commercial liquid silicone rubber are tested.

[0056] 5. Storage stability test: The viscosity of Examples 1-11, Comparative Examples 1-10, and commercially available liquid silicone rubbers after aging in a 50°C oven for 14 days was tested according to GB / T 22235-2008 "Determination of Viscosity of Liquids". The viscosity increase was compared with the initial viscosity to obtain the viscosity growth rate, which was used to evaluate the storage stability of the samples.

[0057] Table 2 details the test data for Experiments 1-5.

[0058] Table 2

[0059] As can be seen from Table 2, a comparison of the test data of Examples 1-5 with Comparative Example 1 and commercially available samples shows that the liquid silicone rubber prepared by modifying silica with hexamethyldisilazane, dimethyldiethoxysilane, and hydroxyl silicone oil has a higher thixotropic index. This indicates that the silica treated with coupling agents effectively alleviates the problem of silica agglomeration in liquid silicone rubber, allowing it to be uniformly dispersed in the system, playing a reinforcing role, and also increasing the viscosity at low shear, thereby improving the thixotropic index.

[0060] A comparison of the test data from Examples 1-5 and Comparative Examples 2-4 in Table 2 shows that the modification of silica requires the simultaneous use of hexamethyldisilazane, dimethyldiethoxysilane, and hydroxyl silicone oil. Only when these three are combined can the modified silica exhibit good thixotropic properties when applied to liquid silicone rubber. Furthermore, Comparative Example 5 demonstrates that the three components must be combined in specific proportions to achieve their full effect; silica modified outside these proportions has little effect on liquid silicone rubber.

[0061] A comparison of the test data from Examples 6 and 5 in Table 2 shows that the liquid silicone rubber prepared using hydroxyl vinyl silicone oil exhibits improved tear performance and increased thixotropy. Furthermore, a comparison of the test data from Examples 7-8 indicates that using silicone oils with specific vinyl and hydroxyl content is beneficial for further improving the thixotropy and tear strength of the liquid silicone rubber.

[0062] The direct and clear data comparison between Example 9 and Comparative Examples 6-8 in Table 2 strongly demonstrates that the surface modification of cellulose by polyethylene glycol mono-p-tert-octylphenyl ether is key to its effective function in silicone rubber, with a significantly increased linewidth in Comparative Example 6. The modified composite structure is the material basis for the dual thixotropic synergistic effect, rather than a simple addition of its components. The thixotropic recovery time of Comparative Examples 7 and 8 is prolonged. The data from Example 9 and Comparative Example 9 prove that even with a good formulation (containing modified cellulose), the special two-step process of partially treating silica with silicone oil first and then adding modified cellulose is still indispensable for avoiding structural damage of modified cellulose under high temperature and high shear and ensuring the performance of the final product.

[0063] The compound produced an unexpected synergistic effect with the silica network treated with a special coupling agent and the hydroxyvinyl silicone oil, achieving a leap in thixotropic index, recovery speed and mechanical strength, far exceeding the expectations of those skilled in the art based on conventional knowledge (such as adding fillers or thickeners alone).

[0064] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this patent.

Claims

1. A thixotropic liquid silicone rubber-based adhesive, characterized in that, The thixotropic liquid silicone rubber base rubber, by mass fraction, contains 30-90% vinyl silicone oil, 10-50% silica, 0.1-10% coupling agent, and 5-25% cellulose.

2. The thixotropic liquid silicone rubber base adhesive according to claim 1, characterized in that, The silica is fumed silica produced by gasification, and preferably has a specific surface area of ​​100-400 m². 2 / g, preferably, the specific surface area of ​​fumed silica is 200-350m² / g. 2 / g; the content of the silica is 10-40%, preferably 20-30%.

3. The thixotropic liquid silicone rubber base adhesive according to claim 1, characterized in that, The vinyl silicone oil has a content of 30-90%, preferably 50-70%; the vinyl silicone oil has a viscosity of 1000-100000 mPa·s at 25°C, preferably 5000-50000 mPa·s; and the vinyl content of the vinyl silicone oil is 0.025-1.5%, preferably 0.04-0.4%.

4. The thixotropic liquid silicone rubber base adhesive according to claim 1, characterized in that, The coupling agent includes HDMS, DMDES, and hydroxyl silicone oil, which are mixed in a weight ratio of 1:(0.5-15):(0.05-0.1); wherein the hydroxyl content of the hydroxyl silicone oil is 0.1-10%, preferably 4%.

5. The thixotropic liquid silicone rubber base adhesive according to claim 1, characterized in that, The coupling agent has a content of 0.2-10%, and the weight ratio of HDMS, DMDES and hydroxyl silicone oil in the coupling agent is 1:(0.1-10):(0.01-1).

6. The thixotropic liquid silicone rubber base adhesive according to claim 1, characterized in that, The liquid silicone rubber also includes hydroxyl vinyl silicone oil, the content of which is 0.01-1% and the viscosity is 10-10000 mPa·s, preferably 100-1000 mPa·s; preferably, the hydroxyl content of which is 1-10% and the vinyl content is 1-30%.

7. The thixotropic liquid silicone rubber base adhesive according to claim 1, characterized in that, The cellulose is one or more of cellulose nanocrystals, cellulose nanofibers, and bacterial cellulose, preferably cellulose nanocrystals.

8. The thixotropic liquid silicone rubber-based adhesive according to claim 1, characterized in that, The cellulose was modified before being added. The modification method is as follows: cellulose nanoparticles were dispersed in anhydrous ethanol, and polyethylene glycol mono-, p-tert-octylphenyl ether was added to perform a surface grafting modification reaction. After the reaction was completed, the nanoparticles were separated and dried to obtain the modified cellulose nanoparticle composite. The amount of polyethylene glycol mono-, p-tert-octylphenyl ether was 5%-50% of the mass of the cellulose nanoparticles; the average diameter of the cellulose nanoparticles was 5-50 nm, and the average length was 100-500 nm; the molecular weight of polyethylene glycol mono-, p-tert-octylphenyl ether was 400-2000.

9. A method for preparing thixotropic liquid silicone rubber, characterized in that, The method includes the following steps: Step a): Mix the silica, the first part of vinyl silicone oil, and the coupling agent evenly and react them. Step b): Continue heat treatment under vacuum conditions; Step c): Add the remaining vinyl silicone oil and polyethylene glycol mono-p-tert-octylphenyl ether modified cellulose, mix evenly under vacuum to obtain thixotropic liquid silicone rubber.

10. The method for preparing thixotropic liquid silicone rubber according to claim 9, characterized in that, In step 1), the mixing conditions are 50℃-100℃ for 0.5-2 hours. The method includes the following step 2): heat treatment at 100-200℃ and under vacuum for 2-4 hours.

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