Matte flame-retardant liquid silica gel and preparation method thereof

Abstract

The invention relates to the technical field of silica gel preparation, in particular to matte flame-retardant liquid silica gel. The liquid silica gel is prepared from the following materials in parts: 30 to 45 parts of vinyl-terminated silicone oil, 5 to 10 parts of methyl silicone oil, 15 to 25 parts of precipitated white carbon black, 3 to 5 parts of hexamethyldisilazane, 3 to 5 parts of hydrogen-containing silicone oil, 0.1 to 1 part of a Karst platinum catalyst, 30 to 45 parts of modified aluminum hydroxide, 15 to 25 parts of active nano calcium carbonate, 0.1 to 0.3 part of polyether modified polysiloxane and 0.1 to 0.2 part of methyl butynol. Hexamethyldisilazane is used for carrying out silanization modification on the surfaces of precipitated white carbon black, modified aluminum hydroxide and active nano calcium carbonate at 120-180 DEG C, so that the filler is more easily dispersed in silicone oil, and a small amount of polyether modified polysiloxane is added, so that the liquid silica gel has a matte effect on the surface after being cured and molded, the service life is prolonged, and the application prospect is wide. And application scenes are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of silica gel preparation, and specifically relates to a matte flame-retardant liquid silica gel and a preparation method thereof. Background Art

[0002] Liquid silicone, also known as liquid silicone, is a liquid rubber relative to solid high-temperature vulcanized silicone rubber. It has the characteristics of good fluidity, rapid curing at high temperature, safety and environmental protection, and can fully meet the requirements of food grade. With the increasing demand for liquid silicone in various industries in the market, the performance requirements for liquid silicone are also getting higher and higher. At the same time, the demand for liquid silicone with excellent composite properties is rapidly increasing. There are many varieties of liquid silicone on the market, but there are very few liquid silicones with matte, flame retardant and adhesive properties at the same time. In specific occasions, they cannot meet the special needs of specific products.

[0003] At present, most of the liquid silicones on the market have a bright surface after curing and have a strong reflective effect on light, which greatly limits their application in some occasions, such as silicone advertising cloth, LED packaging, etc. The liquid silicones required by these two industries must be matte and flame retardant. The liquid silicones on the market add a lot of flame retardants to improve the flame retardancy of the liquid silicone. Although flame retardancy can be easily solved, it is difficult to achieve a matte surface after the liquid silicone is cured. In addition, some liquid silicone powders are added in large amounts, resulting in poor fluidity and high viscosity of the rubber, and even directly made into a paste, which brings great problems to the construction process of many industries. In addition, due to the addition of a large amount of flame retardant fillers, the strength of the colloid is very poor, and the adhesion to various materials is also deteriorated, which cannot meet the requirements of some industries and the service life of the product is greatly reduced. In this regard, we propose a matte flame retardant liquid silicone and a preparation method thereof. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a matte flame-retardant liquid silicone and a preparation method thereof to solve the above technical problems.

[0005] To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a matte flame-retardant liquid silicone, which is prepared from the following materials: 30-45 parts of vinyl-terminated silicone oil, 5-10 parts of methyl silicone oil, 15-25 parts of precipitated silica, 3-5 parts of hexamethyldisilazane, 3-5 parts of hydrogen-containing silicone oil, 0.1-1 parts of Custer platinum catalyst, 30-45 parts of modified aluminum hydroxide, 15-25 parts of active nano-calcium carbonate, 0.1-0.3 parts of polyether-modified polysiloxane, 0.1-0.2 parts of methyl butynol, 0.3-1 parts of di(acetylacetonate) titanate and 1-2 parts of vinyl triethoxysilane.

[0006] Preferably, the liquid silica gel is prepared from the following materials: 35 parts of vinyl-terminated silicone oil, 5 parts of methyl silicone oil, 20 parts of precipitated silica, 4 parts of hexamethyldisilazane, 4 parts of hydrogen-containing silicone oil, 0.5 parts of Custer platinum catalyst, 35 parts of modified aluminum hydroxide, 20 parts of active nano-calcium carbonate, 0.2 parts of polyether-modified polysiloxane, 0.1 parts of methyl butynol, 0.3 parts of diisopropyl di(acetylacetonate) titanate and 1 part of vinyl triethoxysilane.

[0007] The present application uses hexamethyldisilazane to silanize the surface of precipitated white carbon black, modified aluminum hydroxide, and active nano-calcium carbonate at 120°C-180°C, so that the filler can be more easily dispersed in the silicone oil. At the same viscosity, more fillers can be added, the flame retardancy of the rubber is improved, and the tensile strength of the rubber body is guaranteed. The finished liquid silicone has a viscosity of 50000cps-200000cps, a tensile strength of more than 5.0Mpa, and a flame retardancy of FV-0 level;

[0008] A small amount of polyether-modified polysiloxane is added, so that the surface of the liquid silicone has a matte effect after curing and molding. Because of the presence of organic silicon groups, the polyether-modified polysiloxane shows some properties of methyl silicone oil. Its largest application is in the polyurethane industry. It can improve the leveling and wettability of polyurethane rubber and the smoothness of the surface of the product. In addition, the other half of the polyether-modified polysiloxane molecule is a polyether segment, which has a certain hydrophilicity and is incompatible with silicone oil. The present invention utilizes this characteristic of polyether-modified polysiloxane in silicone oil, that is, a small amount of addition can inhibit the surface leveling of the liquid silicone. When the liquid silicone is heated and cured, the surface of the silicone forms an uneven state in a microscopic state, so that the silicone appears matte after molding;

[0009] The addition of an appropriate amount of active nano-calcium carbonate can also have a good synergistic effect on the matte effect of the surface of the silicone after curing; the addition of diisopropyl di(acetylacetonate)titanate and vinylethoxysilane can make the liquid silicone have good adhesion to many materials after curing, such as glass fiber, ceramics, metal, plastic, etc.

[0010] Preferably, the viscosity of the vinyl-terminated silicone oil is 100 cps-60000 cps, the vinyl content is 0.05%-0.80%, the viscosity of the methyl silicone oil is 50 cps-1000 cps, and the specific surface area of ​​the precipitated white carbon black is 100 m 2 / g-175m 2 / g, the viscosity of hydrogen-containing silicone oil is 20cps-200cps, the gas content is 0.05%-0.75%, and the particle size of modified aluminum hydroxide is 300 mesh-5000 mesh.

[0011] A method for preparing matte flame-retardant liquid silicone, the liquid silicone preparation steps are:

[0012] S1. Prepare the following materials: 30-45 parts of vinyl-terminated silicone oil, 5-10 parts of methyl silicone oil, 15-25 parts of precipitated white carbon black, 3-5 parts of hexamethyldisilazane, 3-5 parts of hydrogen-containing silicone oil, 0.1-1 parts of Custer platinum catalyst, 30-45 parts of modified aluminum hydroxide, 15-25 parts of active nano-calcium carbonate, 0.1-0.3 parts of polyether-modified polysiloxane, 0.1-0.2 parts of methyl butynol, 0.3-1 parts of di(acetylacetonate) titanate and 1-2 parts of vinyl triethoxysilane;

[0013] S2, vinyl-terminated silicone oil, methyl silicone oil, precipitated white carbon black, modified aluminum hydroxide, active nano-calcium carbonate and hexamethyldisilazane are put into a vacuum kneader according to the proportion, stirred and kneaded at a temperature below 100°C for 2h-3h, then the kneader is turned on for heating, the materials are heated to 170°C-190°C, and the kneading is continued for 2h-3h, and then the vacuum pump is turned on at 170°C-190°C, and the kneading is carried out under vacuum for 2h;

[0014] S3. After kneading, the material is discharged into a material tray, cooled, and then placed on a three-roll mill for grinding, with the number of grinding times ≥ 3 times;

[0015] S4. After grinding, when the material is cooled to below 40°C, the material is divided into two components, A and B, and small materials are added to the special vacuum high-speed mixer respectively;

[0016] S5. Adding Custer platinum catalyst, diisopropyl di(acetylacetonate)titanate and methyl silicone oil to component A to form material A;

[0017] Adding hydrogen-containing silicone oil, polyether-modified polysiloxane, methyl butynol and vinyl trimethoxy silane to component B to form material B;

[0018] S6. Place material A and material B in a vacuum mixer at a speed of 500 r / min-1000 r / min and a vacuum degree of less than -0.09 MPa for 30 min-60 min, and finally filter and pack in a filter press to obtain matte liquid silica gel with a filter mesh of 100-200 mesh;

[0019] S7. Conduct sampling inspection on the prepared matte liquid silicone.

[0020] Preferably, in step S2, the order of adding is vinyl-terminated silicone oil, methyl silicone oil, precipitated silica, modified aluminum hydroxide, active nano-calcium carbonate and hexamethyldisilazane in this order, and the stirring speed of the vacuum kneader is 1433r / min. As the vacuum pump is started, a negative pressure environment is formed inside, and the air is extracted to form a vacuum environment.

[0021] This application uses a vacuum environment to reduce the loss of volatile components during the mixing process and improve the stability of the material. The negative pressure environment can remove moisture, low-molecular silicone oil and other impurities from the material to improve the purity of the product.

[0022] Preferably, in step S3, the cooling method is air cooling, the temperature of the material is checked during the cooling process, and the material is ground after cooling. The three-roller mill extrude, shear and grind the material through three sets of parallel rollers to refine the material.

[0023] The present application processes materials by using the mechanical energy of a three-roll mill for grinding, which can efficiently refine the materials and improve the uniformity and fineness of the materials. In addition, the three-roll mill reduces energy consumption and production costs during the grinding process.

[0024] Preferably, in step S4, the ground material is placed in a container for cooling, and the material is cooled by air cooling.

[0025] The present application uses air cooling to control the rapid cooling of materials, reduce waiting time and improve production efficiency.

[0026] Preferably, in step S6, the filter pressing and packaging is performed by turning on the hydraulic pump to compress the material through the pressure of the pressure plate, so that the material passes through a 100-200 mesh filter screen, thereby removing impurities in the rubber material, and performing the packaging while filtering.

[0027] Preferably, in step S6, when the filter pressing process reaches a preset end point, the hydraulic pump stops working and the pressure in the material cylinder is gradually released.

[0028] The present application uses a filter press process to apply pressure to allow liquid silica gel to flow out through the filter screen, while solid particles are retained on the filter cloth to form filter residues, thereby achieving efficient filtration, having a better separation effect, efficient energy utilization, reduced material waste, and easy operation and maintenance.

[0029] Preferably, the testing in step S7 includes testing of flame retardancy, matteness and hardness.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The present application uses hexamethyldisilazane to silanize the surfaces of precipitated silica, modified aluminum hydroxide, and active nano-calcium carbonate at 120°C-180°C, so that the filler can be more easily dispersed in the silicone oil. At the same viscosity, more fillers can be added, thereby improving the flame retardancy of the rubber while ensuring the tensile strength of the rubber itself. A small amount of polyether-modified polysiloxane is added to give the liquid silicone a matte surface after curing. The appropriate addition of active nano-calcium carbonate also has a good synergistic effect on the matte effect of the silicone surface after curing, thereby increasing the service life and improving the application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a flowchart of the steps for preparing liquid silica gel of the present invention. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1

[0035] A method for preparing matte flame-retardant liquid silicone, the liquid silicone preparation steps are:

[0036] S1. Prepare the following materials: 35 parts of vinyl-terminated silicone oil, 5 parts of methyl silicone oil, 20 parts of precipitated white carbon black, 4 parts of hexamethyldisilazane, 4 parts of hydrogenated silicone oil, 0.5 parts of Custer platinum catalyst, 35 parts of modified aluminum hydroxide, 20 parts of active nano-calcium carbonate, 0.2 parts of polyether-modified polysiloxane, 0.1 parts of methyl butynol, 0.3 parts of diisopropyl di(acetylacetonate) titanate and 1 part of vinyl triethoxysilane;

[0037] S2, vinyl-terminated silicone oil, methyl silicone oil, precipitated white carbon black, modified aluminum hydroxide, active nano-calcium carbonate and hexamethyldisilazane are put into a vacuum kneader according to a proportion, stirred and kneaded at a temperature below 100° C. for 2 h, then the kneader is turned on for heating, the materials are heated to 180° C., and kneading is continued for 2 h, and then at 180° C., a vacuum pump is turned on and kneaded under vacuum for 2 h;

[0038] S3, after kneading, the material is discharged into a material tray, cooled, and then placed on a three-roll mill for grinding, the number of grinding times is 4 times;

[0039] S4. After grinding, when the material is cooled to below 40°C, the material is divided into two components, A and B, and small materials are added to the special vacuum high-speed mixer respectively;

[0040] S5. Adding Custer platinum catalyst, diisopropyl di(acetylacetonate)titanate and methyl silicone oil to component A to form material A;

[0041] Adding hydrogen-containing silicone oil, polyether-modified polysiloxane, methyl butynol and vinyl trimethoxy silane to component B to form material B;

[0042] S6. Mix material A and material B in a vacuum mixer at a speed of 700 r / min and a vacuum degree of less than -0.09 MPa for 30 min, and finally filter and pack in a filter press to obtain a liquid silica gel base material with a filter mesh of 150 mesh.

[0043] S7. Conduct sampling inspection on the prepared matte liquid silicone.

[0044] Example 2

[0045] A method for preparing matte flame-retardant liquid silicone, the liquid silicone preparation steps are:

[0046] S1. Prepare the following materials: 45 parts of vinyl-terminated silicone oil, 8 parts of methyl silicone oil, 18 parts of precipitated silica, 3 parts of hexamethyldisilazane, 3 parts of hydrogenated silicone oil, 0.3 parts of Custer platinum catalyst, 40 parts of modified aluminum hydroxide, 19 parts of active nano-calcium carbonate, 0.1 parts of polyether-modified polysiloxane, 0.1 parts of methyl butynol, 0.6 parts of di(acetylacetonate) titanate and 2 parts of vinyl triethoxysilane;

[0047] S2, vinyl-terminated silicone oil, methyl silicone oil, precipitated white carbon black, modified aluminum hydroxide, active nano-calcium carbonate and hexamethyldisilazane are put into a vacuum kneader according to a proportion, stirred and kneaded for 3 hours at a temperature below 100° C., then the kneader is turned on for heating, the materials are heated to 190° C., and kneading is continued for 3 hours, and then at 190° C., a vacuum pump is turned on and kneaded under vacuum for 2 hours;

[0048] S3. After kneading, the material is discharged into a material tray, cooled, and then placed on a three-roll mill for grinding for 5 times;

[0049] S4. After grinding, when the material is cooled to below 40°C, the material is divided into two components, A and B, and small materials are added to the special vacuum high-speed mixer respectively;

[0050] S5. Adding Custer platinum catalyst, diisopropyl di(acetylacetonate)titanate and methyl silicone oil to component A to form material A;

[0051] Adding hydrogen-containing silicone oil, polyether-modified polysiloxane, methyl butynol and vinyl trimethoxy silane to component B to form material B;

[0052] S6, material A and material B are respectively placed in a vacuum mixer at a speed of 600r / min and a vacuum degree lower than -0.09Mpa, and vacuum stirred for 40min, and finally filtered and packaged in a filter press to obtain a liquid silica gel base material, and the filter mesh number is 100 mesh;

[0053] S7. Conduct sampling inspection on the prepared matte liquid silicone.

[0054] Comparative Example 1

[0055] The steps for preparing liquid silicone are:

[0056] A1. Prepare raw materials: silane (purity must reach more than 99%), sodium hydroxide, ethylene glycol, isopropanol, water, fillers, additives, masterbatches and additives;

[0057] A2. Select a clean reactor to ensure that there are no impurities and residues. Slowly add silane into the reactor. While maintaining the temperature in the reactor at a suitable level, add sodium hydroxide and water in sequence. After the reaction is completed, add ethylene glycol and isopropanol.

[0058] A3, the mixed raw materials react, and during the reaction process, the temperature in the reactor is maintained within a suitable range;

[0059] A4. After the reaction is completed, the mixture is evaporated by heating and pressurizing to remove the water therein. As the water evaporates, the mixture gradually forms a dense liquid silica gel;

[0060] A5. Carry out finished product inspection on the liquid silicone and check whether the appearance of the liquid silicone is uniform and free of impurities, bubbles and other defects.

[0061] The liquid silicone prepared in Comparative Example 1 has low strength, poor tearing properties, and very poor wear resistance. It is difficult to achieve a matte surface after the liquid silicone is cured. The amount of liquid silicone powder added is large, resulting in poor fluidity and high viscosity of the rubber. The liquid silicone prepared in the embodiment improves the flame retardancy of the rubber while ensuring the tensile strength of the rubber itself. A small amount of polyether-modified polysiloxane is added, so that the surface of the liquid silicone has a matte effect after curing and molding. The appropriate addition of active nano-calcium carbonate also has a good synergistic effect on the matte effect of the surface of the silicone after curing.

[0062] Table 1 below shows the properties of the prepared liquid silica gel.

[0063]

[0064]

[0065] Table 1

[0066] Table 2 below is a table showing the properties of liquid silica gel prepared in different embodiments and comparative examples.

[0067] Group Example 1 Example 2 Comparative Example 1 Is it matte? have have none Flame retardant No combustion No combustion There is a burning situation hardness 58 59 50

[0068] Table 2

[0069] Matte test

[0070] The detection steps are:

[0071] A1. Select representative liquid silicone samples, ensure that the sample quality meets the test requirements and has no obvious defects or contamination, and perform necessary pretreatment on the sample surface, such as cleaning and drying, to ensure the accuracy of the test results;

[0072] A2. Set up the testing environment, adjust the lighting and temperature parameters, and reduce the impact of external factors on the test results;

[0073] A3. Use a photometer to measure the sample surface. The photometer emits a laser beam to the sample surface, measures the intensity and angle of the reflected light, and calculates the gloss value.

[0074] A4. According to the measured gloss value and the requirements of the test standard, determine whether the liquid silicone product has matte properties. If the gloss value is within the matte range specified in the standard, the product is considered to have matte properties.

[0075] Flame retardancy testing

[0076] The detection steps are:

[0077] A1. Select representative liquid silicone specimens to ensure that the sample quality meets the test requirements and has no obvious defects or contamination. Perform necessary pretreatment on the samples, such as cleaning and drying, to ensure the accuracy of the test results.

[0078] A2. Place the prepared sample in a vertical combustion tester, burn the bottom of the sample according to GB / T10707-2008 standard, and test the self-extinguishing time of the sample;

[0079] A3. Use a thermometer and timer to record the condition of the sample;

[0080] A4. Based on the collected data and actual observation results, the flame retardancy of the samples is recorded.

[0081] 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.

[0082] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A matte flame retardant liquid silicone, characterized in that: Liquid silica gel is prepared from the following materials: 30-45 parts of vinyl-terminated silicone oil, 5-10 parts of methyl silicone oil, 15-25 parts of precipitated white carbon black, 3-5 parts of hexamethyldisilazane, 3-5 parts of hydrogen-containing silicone oil, 0.1-1 parts of Custer platinum catalyst, 30-45 parts of modified aluminum hydroxide, 15-25 parts of active nano-calcium carbonate, 0.1-0.3 parts of polyether-modified polysiloxane, 0.1-0.2 parts of methyl butynol, 0.3-1 parts of di(acetylacetonate) titanate and 1-2 parts of vinyl triethoxysilane.

2. The matte flame-retardant liquid silicone rubber according to claim 1, characterized in that: Liquid silica gel is specifically prepared from the following materials: 35 parts of vinyl-terminated silicone oil, 5 parts of methyl silicone oil, 20 parts of precipitated silica, 4 parts of hexamethyldisilazane, 4 parts of hydrogen-containing silicone oil, 0.5 parts of Custer platinum catalyst, 35 parts of modified aluminum hydroxide, 20 parts of active nano-calcium carbonate, 0.2 parts of polyether-modified polysiloxane, 0.1 parts of methyl butynol, 0.3 parts of di(acetylacetonate) titanate and 1 part of vinyl triethoxysilane.

3. The matte flame-retardant liquid silicone according to claim 1, characterized in that: The viscosity of the vinyl-terminated silicone oil is 100cps-60000cps, the vinyl content is 0.05%-0.80%, the viscosity of the methyl silicone oil is 50cps-1000cps, and the specific surface area of ​​the precipitated white carbon black is 100m 2 / g-175m 2 / g, the viscosity of hydrogen-containing silicone oil is 20cps-200cps, the gas content is 0.05%-0.75%, and the particle size of modified aluminum hydroxide is 300 mesh-5000 mesh.

4. A method for preparing matte flame-retardant liquid silicone, characterized in that: The steps for preparing liquid silicone are: S1. Prepare the following materials: 30-45 parts of vinyl-terminated silicone oil, 5-10 parts of methyl silicone oil, 15-25 parts of precipitated white carbon black, 3-5 parts of hexamethyldisilazane, 3-5 parts of hydrogen-containing silicone oil, 0.1-1 parts of Custer platinum catalyst, 30-45 parts of modified aluminum hydroxide, 15-25 parts of active nano-calcium carbonate, 0.1-0.3 parts of polyether-modified polysiloxane, 0.1-0.2 parts of methyl butynol, 0.3-1 parts of di(acetylacetonate) titanate and 1-2 parts of vinyl triethoxysilane; S2, vinyl-terminated silicone oil, methyl silicone oil, precipitated white carbon black, modified aluminum hydroxide, active nano-calcium carbonate and hexamethyldisilazane are put into a vacuum kneader according to the proportion, stirred and kneaded at a temperature below 100°C for 2h-3h, then the kneader is turned on for heating, the materials are heated to 170°C-190°C, and the kneading is continued for 2h-3h, and then the vacuum pump is turned on at 170°C-190°C, and the kneading is carried out under vacuum for 2h; S3. After kneading, the material is discharged into a material tray, cooled, and then placed on a three-roll mill for grinding, with the number of grinding times ≥ 3 times; S4. After grinding, when the material is cooled to below 40°C, the material is divided into two components, A and B, and small materials are added to the special vacuum high-speed mixer respectively; S5. Adding Custer platinum catalyst, diisopropyl di(acetylacetonate)titanate and methyl silicone oil to component A to form material A; Adding hydrogen-containing silicone oil, polyether-modified polysiloxane, methyl butynol and vinyl trimethoxy silane to component B to form material B; S6. Place material A and material B in a vacuum mixer at a speed of 500 r / min-1000 r / min and a vacuum degree of less than -0.09 MPa for 30 min-60 min, and finally filter and pack in a filter press to obtain a liquid silica gel base material with a filter mesh of 100-200 mesh; S7. Conduct sampling inspection on the prepared liquid silicone base material.

5. The method for preparing the matte flame-retardant liquid silicone according to claim 4, characterized in that: In step S2, the order of adding is vinyl-terminated silicone oil, methyl silicone oil, precipitated silica, modified aluminum hydroxide, active nano-calcium carbonate and hexamethyldisilazane. The stirring speed of the vacuum kneader is 35r / min. As the vacuum pump is started, a negative pressure environment is formed inside, and the air is extracted to form a vacuum environment.

6. The method for preparing the matte flame-retardant liquid silicone according to claim 4, characterized in that: In step S3, air cooling is selected as the cooling method. The temperature of the material is checked during the cooling process. After cooling, the material is ground. The three-roller mill extrude, shear and grind the material through three sets of parallel rollers to refine the material.

7. The method for preparing matte flame-retardant liquid silicone according to claim 4, characterized in that: In step S4, the ground material is placed in a container for cooling, and the material is cooled by air cooling.

8. The method for preparing matte flame-retardant liquid silicone according to claim 4, characterized in that: In step S6, the filter pressing and packaging is performed by turning on the hydraulic pump to compress the material through the pressure of the pressure plate, so that the material passes through a 100-200 mesh filter screen, thereby removing impurities in the rubber material and performing packaging while filtering.

9. The method for preparing matte flame-retardant liquid silicone according to claim 4, characterized in that: In step S6, when the filtration process reaches a preset end point, the hydraulic pump stops working and the pressure in the material cylinder is gradually released.

10. The method for preparing matte flame-retardant liquid silicone according to claim 4, characterized in that: The tests in step S7 include flame retardancy test, matte test and hardness test.

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