Low-viscosity high-tear-resistance bi-component addition type liquid silicone rubber and preparation method thereof

Abstract

The preparation method comprises the following steps: putting vinyl-terminated silicone oil, fumed silica, MQ resin, enol, a fumed silica treating agent and water into a kneading machine according to a certain proportion and sequence, stirring at room temperature for 3 hours, starting vacuum stirring, heating to 120-160 DEG C, stirring at high temperature for 3 hours, and cooling to room temperature to obtain the low-viscosity high-tear-resistance double-component addition type liquid silicone rubber. After the rubber material is cooled, respectively adding a platinum catalyst to prepare a rubber A, and adding hydrogen-containing silicone oil, polyvinyl silicone oil and an inhibitor to prepare a rubber B; the method is simple in process, the prepared AB glue is low in viscosity and can be used for preparing high-hardness and high-tear silicone rubber products, the main raw materials are low-risk substances, the storage period of the prepared AB glue exceeds 12 months, and the AB glue is colorless and transparent in appearance and good in fluidity.

Description

Technical Field

[0001] The invention relates to the technical field of silicone rubber, and in particular to a low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber and a preparation method thereof. Background Art

[0002] Silicone rubber is a material with the chemical nature of polydimethylsiloxane (PDMS). It has attracted widespread attention due to its excellent radiation resistance, thermal stability, biocompatibility, etc. According to the physical form of the uncrosslinked rubber, silicone rubber can be divided into solid silicone rubber (SSR) in a "gel-like" state and liquid silicone rubber (LSR) in a liquid state. Addition-type liquid silicone rubber (LSR) is a new type of material that is not easy to deform, has a low shrinkage rate and has excellent physiological inertness. This two-component liquid rubber system can be pumped into appropriate injection molding equipment and then thermally cured into molded rubber parts, which can achieve large-scale industrial production. However, LSR usually requires the addition of various reinforcing materials to achieve the mechanical strength required for industrial applications. Because silica and polysiloxane have a high structural similarity and can interact with each other, greatly improving the performance of silicone rubber after crosslinking, so far, silica has become the most widely used silicone rubber reinforcing filler on an industrial scale. Although the exact reinforcement mechanism of silica is still unclear, it is generally believed that the "three-dimensional network" formed by the interaction between fillers and fillers and the interaction between fillers and polymers plays a major role in the silica reinforcement system. In the LSR system, due to the strong interaction caused by the intermolecular hydrogen bonding, the formation of the silicone rubber cross-linked network will not only improve the strength of the material, but also significantly increase the viscosity of the LSR system, making its fluidity worse and inconvenient for large-scale production. Therefore, it is of great significance and wide application value to prepare a liquid silicone rubber with good fluidity, high tensile strength and high tear strength. The present invention proposes to use enol to modify silica. First, its alcohol hydroxyl group can be modified by esterification with silanol to modify the silica surface; second, its olefin group can react with the cross-linking agent in the vulcanization system. In this way, due to the low density of hydroxyl groups on the surface of the modified silica, it is expected that the viscosity will be reduced (fluidity will be increased), and the mechanical properties can also be improved by forming a filler-polymer cross-linked network.

[0003] Patent CN111534106A discloses a method for preparing a medical liquid silicone rubber with high tear strength. The silicone rubber prepared has good tear resistance, but the fluidity of the rubber will deteriorate when the hardness is high (52 ShoreA).

[0004] Patent CN111303639B discloses a method for preparing a low-hardness, high-tear-resistant self-lubricating addition-type liquid silicone rubber, which can obtain relatively good tear resistance at a relatively low hardness, but it does not meet the requirements of some products that require high hardness. Summary of the invention

[0005] In view of the deficiencies in the prior art, the present invention provides a low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber and a preparation method thereof, so as to solve the problems of poor physical properties and fluidity under high hardness conditions existing in existing liquid silicone rubber products.

[0006] The present invention is achieved through the following technical scheme: A low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber and a preparation method thereof require the following raw materials: Component A and component B are composed in a mass ratio of 1:1; Among them, component A is composed of the following raw materials by mass: 50-70 parts of vinyl-terminated polysiloxane, 3-10 parts of fumed silica treating agent, 1-5 parts of water, 1-5 parts of enol, 25-40 parts of fumed silica, 10-20 parts of MQ resin, and 0.02-0.1 parts of platinum catalyst; Component B is composed of the following raw materials by mass: 50-70 parts of vinyl-terminated polysiloxane, 3-10 parts of fumed silica treating agent, 25-40 parts of fumed white carbon black, 1-5 parts of water, 10-20 parts of MQ resin, 2-20 parts of hydrogen-containing silicone oil, 0.1-1 part of polyvinyl silicone oil, and 0.01-0.05 parts of inhibitor.

[0007] In component A and component B, the vinyl mass percentage of the vinyl-terminated polysiloxane is 0.1 to 1.0%, and the viscosity at 25° C. is 20,000 to 100,000 mPa.s.

[0008] In component A and component B, the fumed silica treating agent is one or more of dimethyldiethoxysilane, dimethyldimethoxysilane, dimethylcyclosiloxane, hexamethyldisilazane, and trimethylethoxysilane.

[0009] In component A and component B, the fumed silica is treated with a fumed silica treatment agent to make it hydrophobic, and the specific surface area of ​​the fumed silica is 200 m 2 / g~400m 2 / g.

[0010] In component A and component B, the silicone resin is vinyl MQ silicone resin, and the vinyl content is 1%-4%.

[0011] The enol in component A is any one of propenol, 4-hexenol, cis-4-decen-1-ol, trans-2-undecenol, trans-2-dodecenol, 1-dodecanol, cis-9-tetradecenol, and cis-9-octadecen-1-ol.

[0012] The platinum catalyst in component A is a chloroplatinic acid tetramethyl divinyl disiloxane complex, wherein the mass content of platinum is 1000-3000 ppm.

[0013] In component B, the hydrogen-containing silicone oil is one or more of side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, and end-side hydrogen-containing silicone oil, and the mass percentage of hydrogen is 0.05-1%.

[0014] In component B, the vinyl content of the polyvinyl silicone oil is 1%-15%.

[0015] In component B, the inhibitor is a vinyl ring or ethynyl cyclohexanol.

[0016] A low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber and a preparation method thereof, comprising the following steps: Step 1. Prepare component A Add 40-80% of vinyl-terminated polysiloxane, a certain amount of fumed silica treatment agent, a certain amount of fumed silica, ene alcohol and a certain amount of water to the kneader in batches, and stir at room temperature for 1-4 hours; heat to 120-180°C, stir under vacuum for 1-4 hours, then stop the vacuum, add vinyl MQ silicone resin and the remaining vinyl-terminated polysiloxane to the kneader for dilution, stir under vacuum for 1-2 hours, then add a certain amount of platinum catalyst, stir evenly to obtain component A; Step 2. Prepare component B Add 40-80% of vinyl-terminated polysiloxane, a certain amount of fumed silica treatment agent, a certain amount of fumed white carbon black and a certain amount of water to the kneader in batches, and stir at room temperature for 1-4 hours; heat to 120-180°C, stir under vacuum for 1-4 hours, then stop the vacuum, add vinyl MQ silicone resin and the remaining vinyl polysiloxane to the kneader for dilution, stir under vacuum for 1-2 hours, then add a certain amount of hydrogenated silicone oil and a certain amount of inhibitor, stir evenly, and obtain component B; Step 3: Mix component A and component B in a mold at a mass ratio of 1:1, perform compression vulcanization on a flat vulcanizer, the vulcanization temperature is 100-160° C., and the vulcanization time is 3-20 min to obtain the silicone rubber.

[0017] Compared with the prior art, the present invention has the following advantages: The present invention proposes to use enol to modify silica. First, its alcoholic hydroxyl group can modify the silica surface by esterification with silanol; second, its olefin group can undergo addition reaction with the crosslinking agent in the vulcanization system, and the long-chain olefin can achieve better tear resistance under the condition of high Shore hardness. In this way, due to the low density of hydroxyl groups on the surface of the modified silica, it is expected that the viscosity will be reduced (the fluidity will be increased), and the mechanical properties can also be improved by forming a filler-polymer crosslinking network.

[0018] The liquid silicone rubber sheet prepared by the present invention has good fluidity, maintains good tear resistance under high Shore hardness, can meet ISO10993, USP and other standards, and can meet the processing performance of liquid injection molding silicone. After a detailed investigation of addition-type liquid silicone rubber products and technologies at home and abroad, the physical properties of the two-component addition-type liquid silicone rubber product prepared by the present invention can reach or even exceed similar products at home and abroad. DETAILED DESCRIPTION

[0019] The present invention is further explained below with reference to the examples, but the examples do not limit the present invention in any form.

[0020] A low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber and a preparation method thereof, comprising component A and component B in a mass ratio of 1:1; Among them, component A is composed of the following raw materials by mass: 50-70 parts of vinyl-terminated polysiloxane, 3-10 parts of fumed silica treatment agent, 1-5 parts of water, 25-40 parts of fumed silica, 1-5 parts of enol, 10-20 parts of MQ resin, and 0.02-0.1 parts of platinum catalyst; Component B is composed of the following raw materials by mass: 50-70 parts of vinyl-terminated polysiloxane, 3-10 parts of fumed silica treating agent, 25-40 parts of fumed white carbon black, 1-5 parts of water, 10-20 parts of MQ resin, 2-20 parts of hydrogen-containing silicone oil, 0.1-1 part of polyvinyl silicone oil, and 0.01-0.05 parts of inhibitor.

[0021] The vinyl mass percentage of the vinyl-terminated polysiloxane in component A and component B is 0.1-1.0%, and the viscosity at 25° C. is 10000-100000 mPa. s. The fumed silica treating agent is one or more of dimethyldiethoxysilane, dimethyldimethoxysilane, dimethylcyclosiloxane, hexamethyldisilazane, and trimethylethoxysilane. The fumed silica is treated with a silane coupling agent to be hydrophobic, and the specific surface area is 200 m 2 / g~400m 2 / g.

[0022] The platinum catalyst in component A is a chloroplatinic acid tetramethyldivinyldisiloxane complex, in which the mass content of platinum is 100-3000ppm.

[0023] The hydrogen mass percentage of the hydrogen-containing silicone oil in component B is 0.05-1%, wherein the hydrogen mass percentage of the side hydrogen-containing polysiloxane is 0.2-1.6%. The inhibitor is a vinyl ring or ethynyl cyclohexanol.

[0024] The method for preparing the above-mentioned low-viscosity and high-tear-resistant two-component addition-type liquid silicone rubber comprises the following steps: Preparation of component A Add 40-80% of vinyl-terminated polysiloxane, a certain amount of fumed silica treatment agent, a certain amount of fumed silica, a certain amount of enol and a certain amount of water to the kneader in batches, and stir at room temperature for 1-4 hours; heat to 120-180°C, stir under vacuum for 1-4 hours, then stop the vacuum, add the remaining vinyl polysiloxane to the kneader for dilution, keep the vacuum for 1-2 hours, then add a certain amount of platinum catalyst, stir evenly to obtain component A; Preparation of component B Add 40-80% of vinyl-terminated polysiloxane, a certain amount of fumed silica treatment agent, a certain amount of fumed white carbon black and a certain amount of water to the kneader in batches, and stir at room temperature for 1-4 hours; heat to 120-180° C., stir under vacuum for 1-4 hours, then stop the vacuum, add the remaining vinyl-terminated polysiloxane to the kneader for dilution, stir under vacuum for 1-2 hours, then add a certain amount of hydrogenated silicone oil, a certain amount of polyvinyl silicone oil and a certain amount of inhibitor, stir evenly, and obtain component B; Mix components A and B The component A and the component B are mixed uniformly in a mass ratio of 1:1, and subjected to compression vulcanization on a flat vulcanizer at a vulcanization temperature of 100-160° C. and a vulcanization time of 3-20 min to obtain the silicone rubber.

[0025] The fumed silica involved in the following examples and comparative examples is HL-380 provided by Huifu, and the hydrogen-containing silicone oil is RH-H512 provided by Runhe.

[0026] Example 1 Preparation of component A Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60,000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1wt%, vinylsilazane 5wt%), 30 parts of fumed silica, 3.5 parts of trans-2-dodecenol and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 9 parts of MQ resin and 1.6 parts of chloroplatinic acid tetramethyl divinyl disiloxane complex in sequence, stir evenly, and obtain component A; Preparation of component B Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1 wt%, vinylsilazane 5 wt%), 30 parts of fumed silica and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop the vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 5 parts of side hydrogenated silicone oil with a viscosity of 80mPa.s and a hydrogen content of 1.2%, 0.9 parts of polyvinyl silicone oil with a vinyl content of 9% and 0.4 of an inhibitor (cyclohexanol) in sequence, stir evenly, and obtain component B; Component A and component B were uniformly mixed in a mass ratio of 1:1, and vulcanized at 140° C. for 10 minutes to obtain the silicone rubber.

[0027] The performance parameters of the prepared two-component addition-type liquid silicone rubber are shown in Table 1.

[0028] Example 2 Preparation of component A Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1wt%, vinylsilazane 5wt%), 30 parts of fumed silica, 3.5 parts of trans-2-undecenol and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 9 parts of MQ resin and 1.6 parts of chloroplatinic acid tetramethyl divinyl disiloxane complex in sequence, stir evenly, and obtain component A; Preparation of component B Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1 wt%, vinylsilazane 5 wt%), 30 parts of fumed silica and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop the vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 5 parts of side hydrogenated silicone oil with a viscosity of 80mPa.s and a hydrogen content of 1.2%, 0.9 parts of polyvinyl silicone oil with a vinyl content of 9% and 0.4 of an inhibitor (cyclohexanol) in sequence, stir evenly, and obtain component B; Component A and component B were uniformly mixed in a mass ratio of 1:1, and vulcanized at 140° C. for 10 minutes to obtain the silicone rubber.

[0029] The performance parameters of the prepared two-component addition-type liquid silicone rubber are shown in Table 1.

[0030] Example 3 Preparation of component A Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1wt%, vinylsilazane 5wt%), 30 parts of fumed silica, 3.5 parts of cis-4-decene-1-ol and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 9 parts of MQ resin and 1.6 parts of chloroplatinic acid tetramethyl divinyl disiloxane complex in sequence, stir evenly, and obtain component A; Preparation of component B Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1 wt%, vinylsilazane 5 wt%), 30 parts of fumed silica and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop the vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 5 parts of side hydrogenated silicone oil with a viscosity of 80mPa.s and a hydrogen content of 1.2%, 0.9 parts of polyvinyl silicone oil with a vinyl content of 9% and 0.4 of an inhibitor (cyclohexanol) in sequence, stir evenly, and obtain component B; Component A and component B were uniformly mixed in a mass ratio of 1:1, and vulcanized at 140° C. for 10 minutes to obtain the silicone rubber.

[0031] The performance parameters of the prepared two-component addition-type liquid silicone rubber are shown in Table 1.

[0032] Example 4 Preparation of component A Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60,000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1wt%, vinylsilazane 5wt%), 30 parts of fumed silica, 3.5 parts of propylene alcohol and 1.9 parts of water, stir into a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 9 parts of MQ resin and 1.6 parts of chloroplatinic acid tetramethyl divinyl disiloxane complex in sequence, stir evenly, and obtain component A; Preparation of component B Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1 wt%, vinylsilazane 5 wt%), 30 parts of fumed silica and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop the vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 5 parts of side hydrogenated silicone oil with a viscosity of 80mPa.s and a hydrogen content of 1.2%, 0.9 parts of polyvinyl silicone oil with a vinyl content of 9% and 0.4 of an inhibitor (cyclohexanol) in sequence, stir evenly, and obtain component B; Component A and component B were uniformly mixed in a mass ratio of 1:1, and vulcanized at 140° C. for 10 minutes to obtain the silicone rubber.

[0033] The performance parameters of the prepared two-component addition-type liquid silicone rubber are shown in Table 1.

[0034] Example 5 Preparation of component A Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1wt%, vinylsilazane 5wt%), 30 parts of fumed silica, 3.5 parts of 4-hexene-alcohol and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 9 parts of MQ resin and 1.6 parts of chloroplatinic acid tetramethyl divinyl disiloxane complex in sequence, stir evenly, and obtain component A; Preparation of component B Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1 wt%, vinylsilazane 5 wt%), 30 parts of fumed silica and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum 0.7MPa for 2h, then stop the vacuum, cool down and add 30 parts of vinyl-terminated polysiloxane, 5 parts of side hydrogenated silicone oil with a viscosity of 80mPa.s and a hydrogen content of 1.2%, 0.9 parts of polyvinyl silicone oil with a vinyl content of 9% and 0.4 of an inhibitor (cyclohexanol) in sequence, stir evenly to obtain component B; Component A and component B were uniformly mixed in a mass ratio of 1:1, and vulcanized at 140° C. for 10 minutes to obtain the silicone rubber.

[0035] The performance parameters of the prepared two-component addition-type liquid silicone rubber are shown in Table 1.

[0036] Example 6 Preparation of component A Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25° C. and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1wt%, vinylsilazane 5wt%), 30 parts of fumed silica, 3.5 parts of cis-9-tetradecenol and 1.9 parts of water, stir into a mass, and continue stirring at room temperature for 2h; heat to 130° C., stir under vacuum of 0.7MPa for 2h, then stop vacuum, cool, add 30 parts of vinyl-terminated polysiloxane, 9 parts of MQ resin and 1.6 parts of chloroplatinic acid tetramethyl divinyl disiloxane complex in sequence, stir evenly, and obtain component A; Preparation of component B Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1 wt%, vinylsilazane 5 wt%), 30 parts of fumed silica and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop the vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 5 parts of side hydrogenated silicone oil with a viscosity of 80mPa.s and a hydrogen content of 1.2%, 0.9 parts of polyvinyl silicone oil with a vinyl content of 9% and 0.4 of an inhibitor (cyclohexanol) in sequence, stir evenly, and obtain component B; Component A and component B were uniformly mixed in a mass ratio of 1:1, and vulcanized at 140° C. for 10 minutes to obtain the silicone rubber.

[0037] The performance parameters of the prepared two-component addition-type liquid silicone rubber are shown in Table 1.

[0038] Example 7 Preparation of component A Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1wt%, vinylsilazane 5wt%), 30 parts of fumed silica, 3.5 parts of cis-9-octadecene-1-ol and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 9 parts of MQ resin and 1.6 parts of chloroplatinic acid tetramethyl divinyl disiloxane complex in sequence, stir evenly, and obtain component A; Preparation of component B Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1 wt%, vinylsilazane 5 wt%), 30 parts of fumed silica and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop the vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 5 parts of side hydrogenated silicone oil with a viscosity of 80mPa.s and a hydrogen content of 1.2%, 0.9 parts of polyvinyl silicone oil with a vinyl content of 9% and 0.4 of an inhibitor (cyclohexanol) in sequence, stir evenly, and obtain component B; Component A and component B were uniformly mixed in a mass ratio of 1:1, and vulcanized at 140° C. for 10 minutes to obtain the silicone rubber.

[0039] The performance parameters of the prepared two-component addition-type liquid silicone rubber are shown in Table 1.

[0040] Comparative Example 1 Preparation of component A Add 30 parts of vinyl-terminated polysiloxane having a viscosity of 60,000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1 wt%, vinylsilazane 5 wt%), 30 parts of fumed silica and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop the vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 9 parts of MQ resin and 1.6 parts of chloroplatinic acid tetramethyl divinyl disiloxane complex in sequence, stir evenly, and obtain component A; Preparation of component B Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1 wt%, vinylsilazane 5 wt%), 30 parts of fumed silica and 1.9 parts of water, stir to form a mass and continue stirring at room temperature for 2h; heat to 130°C, stir under vacuum of 0.7MPa for 2h, then stop the vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 5 parts of side hydrogenated silicone oil with a viscosity of 80mPa.s and a hydrogen content of 1.2%, 0.9 parts of polyvinyl silicone oil with a vinyl content of 9% and 0.4 of an inhibitor (cyclohexanol) in sequence, stir evenly, and obtain component B; Component A and component B were uniformly mixed in a mass ratio of 1:1, and vulcanized at 140° C. for 10 minutes to obtain the silicone rubber.

[0041] The performance parameters of the prepared two-component addition-type liquid silicone rubber are shown in Table 1.

[0042] Comparative Example 2 Preparation of component A Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25° C. and a vinyl mass percentage of 0.08% in batches in a kneader, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1wt%, vinylsilazane 5wt%), 30 parts of fumed silica, 3.5 parts of 1-dodecanol and 1.9 parts of water, stir into a mass, and continue stirring at room temperature for 2h; heat to 130° C., stir for 2h under vacuum of 0.7MPa, then stop vacuum, cool, add 30 parts of vinyl-terminated polysiloxane, 9 parts of MQ resin and 1.6 parts of chloroplatinic acid tetramethyl divinyl disiloxane complex in sequence, stir evenly, and obtain component A; Preparation of component B Add 30 parts of vinyl-terminated polysiloxane with a viscosity of 60000 mPa.s at 25°C and a vinyl mass percentage of 0.08%, 5.75 parts of fumed silica modifier (tetramethyldisilazane 94wt%, trimethylethoxysilane 1 wt%, vinylsilazane 5 wt%), 30 parts of fumed silica and 1.9 parts of water in batches in a kneader, stir to form a mass, and continue stirring at room temperature for 2 hours; heat to 130°C, stir under vacuum of 0.7MPa for 2 hours, then stop the vacuum, cool down, add 30 parts of vinyl-terminated polysiloxane, 5 parts of side hydrogenated silicone oil with a viscosity of 80mPa.s and a hydrogen content of 1.2%, 0.9 parts of polyvinyl silicone oil with a vinyl content of 9% and 0.4 of an inhibitor (cyclohexanol) in sequence, stir evenly, and obtain component B; Component A and component B were mixed evenly in a mass ratio of 1:1, and vulcanized at 140° C. for 10 minutes to obtain the silicone rubber.

[0043] The performance parameters of the prepared two-component addition-type liquid silicone rubber are shown in Table 1.

[0044] Table 1

[0045] At room temperature, an AI-7000S1 tensile testing machine (High Speed ​​Rail Testing Instruments (Dongguan) Co., Ltd.) was used to measure the hardness of the antibacterial liquid silicone rubber after vulcanization in accordance with GB-T531.1-2008, the tear strength of the antibacterial liquid silicone rubber after vulcanization was measured in accordance with GB-T 529-2008, and the tensile strength and elongation at break of the antibacterial liquid silicone rubber after vulcanization were measured in accordance with GB-T 528-2009.

[0046] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principle of the present invention. These improvements should also be regarded as the scope of protection of the present invention.

Claims

1. A low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber, characterized in that: It comprises glue A and glue B, wherein glue A comprises the following raw materials: 50-70 parts of vinyl-terminated polysiloxane, 3-10 parts of fumed silica treating agent, 1-5 parts of water, 1-5 parts of enol, 25-40 parts of fumed silica, 10-20 parts of MQ resin, and 0.02-0.1 parts of platinum catalyst; Glue B includes the following raw materials: 50-70 parts of vinyl-terminated polysiloxane, 3-10 parts of fumed silica treating agent, 25-40 parts of fumed white carbon black, 1-5 parts of water, 10-20 parts of MQ resin, 2-20 parts of hydrogen-containing silicone oil, 0.1-1 part of polyvinyl silicone oil, and 0.01-0.05 parts of inhibitor.

2. The low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber according to claim 1, characterized in that: The vinyl mass percentage of terminal vinyl polysiloxane in A and B glues is 0.1~~1.0%, and the viscosity is 20000~100000 mPa.s at 25°C.

3. The low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber according to claim 1, characterized in that: The fumed silica treating agent is one or more of dimethyldiethoxysilane, dimethyldimethoxysilane, dimethylcyclosiloxane, hexamethyldisilazane and trimethylethoxysilane.

4. The low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber according to claim 1, characterized in that: The fumed silica is treated with a fumed silica treatment agent to make it hydrophobic, and the specific surface area is 200m 2 / g~400m 2 / g.

5. The low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber according to claim 1, characterized in that: The silicone resin is vinyl MQ silicone resin, and the vinyl content is 1%-4%.

6. The low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber according to claim 1, characterized in that: The enol in component A is any one of propenol, 4-hexenol, cis-4-decen-1-ol, trans-2-undecenol, trans-2-dodecenol, 1-dodecanol, cis-9-tetradecenol, and cis-9-octadecen-1-ol.

7. The low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber according to claim 1, characterized in that: The platinum catalyst is a chloroplatinic acid tetramethyldivinyldisiloxane complex, wherein the mass content of platinum is 1000-3000 ppm.

8. The low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber according to claim 1, characterized in that: The hydrogen-containing silicone oil is one or more of side hydrogen-containing silicone oil, end hydrogen-containing silicone oil, and end-side hydrogen-containing silicone oil, and the mass percentage of hydrogen is 0.05-1%; the vinyl content of the polyvinyl silicone oil is 1%-15%; the inhibitor is a vinyl ring or ethynyl cyclohexanol.

9. The method for preparing a low-viscosity and high-tear resistance two-component addition-type liquid silicone rubber according to any one of claims 1 to 8, characterized in that: The steps include: Step 1: Prepare component A Add 40-80% of vinyl-terminated polysiloxane, fumed silica treatment agent and fumed silica, enol and water to the kneader in batches, and stir at room temperature for 1-4 hours; heat to 120-180° C., stir under vacuum for 1-4 hours, then stop the vacuum, add vinyl MQ silicone resin and the remaining vinyl-terminated polysiloxane to the kneader for dilution, stir under vacuum for 1-2 hours, then add a certain amount of platinum catalyst, and stir evenly to obtain component A; Step 2: Prepare component B Add 40-80% of vinyl-terminated polysiloxane, a certain amount of fumed silica treatment agent, a certain amount of fumed white carbon black and a certain amount of water to the kneader in batches, and stir at room temperature for 1-4 hours; heat to 120-180°C, stir under vacuum for 1-4 hours, then stop the vacuum, add vinyl MQ silicone resin and the remaining vinyl polysiloxane to the kneader for dilution, stir under vacuum for 1-2 hours, then add a certain amount of hydrogenated silicone oil and a certain amount of inhibitor, stir evenly, and obtain component B; Step 3: Mix component A and component B in a mold at a mass ratio of 1:1, perform compression vulcanization on a flat vulcanizer, the vulcanization temperature is 100-160°C, and the vulcanization time is 3-20 minutes to obtain the silicone rubber.

10. The preparation method according to claim 9, characterized in that: The A glue is colorless and transparent in appearance, and has a viscosity of 1000000-10000000 cP; the B glue is colorless and transparent in appearance, and has a viscosity of 1000000-10000000 cP.

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