High-strength liquid silicone rubber composition and preparation method thereof

Abstract

The invention discloses a high-strength liquid silicone rubber composition and a preparation method thereof. The rubber composition comprises the following raw material components in parts by weight: 100.0 parts of vinyl-terminated silicone oil; 30.0 parts to 45.0 parts of modified white carbon black; 1.0 to 5.0 parts of modified nano titanium dioxide; 14.0 parts to 26.0 parts of aluminum hydroxide; 7.0 parts to 9.0 parts of hydrogen-containing silicone oil; 1.0 part to 5.0 parts of a silane coupling agent; 0.2 to 0.5 part of a catalyst; wherein the modified white carbon black is prepared by modifying white carbon black prepared by a vapor phase method through dimethyldichlorosilane or trimethylchlorosilane, and the modified nano titanium dioxide is prepared by modifying through a surface silicon deposition method; the particle size of the white carbon black prepared by the gas phase method is 5-50 nm, and the BET specific surface area of the white carbon black prepared by the gas phase method is 300-400 m < 2 > / g. The strength of the product is improved by adding the inorganic filler, and the nano titanium dioxide is modified by a surface silicon deposition method, so that the surface energy of the nano titanium dioxide is remarkably improved, and the dispersity and fluidity of the liquid silicone rubber are improved.

Description

Technical Field

[0001] The invention relates to the technical field of liquid silicone rubber, in particular to a high-strength liquid silicone rubber composition and a preparation method thereof. Background Art

[0002] With the development of science and technology and the overall progress of society, silicone rubber has become one of the basic materials for improving the comprehensive performance of products in many manufacturing fields. With the expansion of applications and the upgrading of various products, various fields have put forward higher requirements for the performance, molding accuracy and efficiency of silicone rubber products. According to the form of the rubber before vulcanization molding, silicone rubber can be divided into compound silicone rubber and liquid silicone rubber. Compound silicone rubber presents a solid-like characteristic and is usually molded or calendered. Liquid silicone rubber has good fluidity, self-leveling or thixotropy, and flexible processing performance. It is suitable for a variety of molding methods and one-time molding of products with complex structures and shapes. Combined with injection molding technology that can be produced continuously, it has incomparable advantages over solid silicone rubber in terms of preparation efficiency, molding accuracy, and manufacturing cost.

[0003] For liquid silicone rubber, the use of inorganic nanofillers for reinforcement will lead to a significant deterioration in its fluidity. When the amount of filler is large, it will even lose its fluidity and cannot meet the viscosity requirements of the injection molding process.

[0004] The defects of existing liquid silicone rubber are:

[0005] 1. Patent document CN101983989A discloses a liquid silicone rubber composition and a preparation method thereof, but the preparation method of the liquid silicone rubber composition in the patent document does not consider how to solve the contradiction between the mechanical enhancement and processing fluidity of the liquid silicone rubber;

[0006] 2. Patent document CN102876046B proposes a liquid silicone rubber composition and a preparation method thereof. However, the patent document only considers improving the tensile strength and tear resistance of the liquid silicone rubber product after vulcanization by adding white carbon black, and does not consider improving the stability of the liquid silicone rubber product after vulcanization;

[0007] 3. The liquid silicone rubber composition prepared by the liquid silicone rubber composition preparation method in the prior art does not consider improving the flame retardant properties of the liquid silicone rubber composition. Summary of the invention

[0008] The object of the present invention is to provide a high-strength liquid silicone rubber composition and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0009] To achieve the above object, the present invention provides the following technical solution: a high-strength liquid silicone rubber composition and a preparation method thereof, wherein the rubber composition comprises the following raw materials in parts by weight:

[0010] 100.0 parts of vinyl-terminated silicone oil;

[0011] 30.0 to 45.0 parts of modified white carbon black;

[0012] 1.0 to 5.0 parts of modified nano titanium dioxide

[0013] 14.0 to 26.0 parts of aluminum hydroxide;

[0014] 7.0 to 9.0 parts of hydrogen silicone oil;

[0015] 1.0 to 5.0 parts of silane coupling agent;

[0016] 0.2 to 0.5 parts of catalyst;

[0017] The modified white carbon black is prepared by gas phase method by modification of dimethyldichlorosilane or trimethylchlorosilane, and the modified nano titanium dioxide is prepared by surface silicon deposition; the particle size of the white carbon black prepared by gas phase method is 5nm-50nm, and the BET specific surface area of ​​the white carbon black prepared by gas phase method is 300m 2 / g~400m2 / g.

[0018] Preferably, the preparation method of the modified nano titanium dioxide is as follows: immersing the nano titanium dioxide in a hexane solvent of methyl silicone oil, stirring evenly, evaporating and drying, and finally calcining in a muffle furnace at 700° C. for 2 hours to obtain modified nano titanium dioxide powder.

[0019] Preferably, the components of the liquid silicone rubber composition further include an activator, wherein the activator is zinc oxide and stearic acid, and the activator includes 4.0 to 7.0 parts of zinc oxide and 0.75 to 1.25 parts of stearic acid in parts by weight.

[0020] Preferably, the BET specific surface area of ​​the aluminum hydroxide is 10 m 2 / g~20m 2 / g, and the particle size of aluminum hydroxide is 1um~10um.

[0021] Preferably, the silane coupling agent is Si-69 silane coupling agent.

[0022] Preferably, the catalyst is a platinum catalyst, and the content of the platinum catalyst is 10ppm to 25ppm.

[0023] Preferably, the platinum catalyst is one of treated platinum, platinum black, chloroplatinic acid, ethanol-modified chloroplatinic acid, chloroplatinic acid / olefin complex and chloroplatinic acid / olefin siloxane complex.

[0024] Preferably, the components of the liquid silicone rubber composition further include one or more of a vulcanizing agent, a vulcanization accelerator, an antioxidant and a plasticizer.

[0025] Preferably, a method for preparing a high-strength liquid silicone rubber composition comprises the following steps:

[0026] Step S1: weigh the components according to weight;

[0027] Step S2: adding the weighed vinyl-terminated silicone oil into a mixing box and stirring, then adding modified white carbon black and modified nano titanium dioxide, and stirring with a stirrer;

[0028] Step S3: adding the weighed aluminum hydroxide, silane coupling agent and activator into the mixing box and stirring to obtain a basic rubber material, and the stirring time is 10 minutes in total;

[0029] Step S4: taking out half of the base rubber prepared in step S3, adding weighed hydrogen-containing silicone oil and platinum catalyst to the taken out base rubber, and stirring evenly to obtain a mixed rubber;

[0030] Step S5: Evenly mix the mixed rubber obtained in the above step S4 and the remaining half of the base rubber obtained in the above step S3 to obtain a high-strength liquid silicone rubber composition.

[0031] Preferably, the rotation speed of the stirrer is set to 2000 rpm, the stirring time of step S2 is set to 2 min, the stirring time of step S3 is set to 8 min, the stirring time of step S4 is set to 6 min, and the stirring time of step S5 is 5 min. The stirring operations are all carried out at a temperature of 25 to 35°C.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] 1. In the present invention, the strength of the product is improved by adding inorganic nano-titanium dioxide, and the nano-titanium dioxide is modified by the method of surface silicon deposition, which significantly improves the surface energy of the nano-titanium dioxide, thereby improving the dispersibility and fluidity of the liquid silicone rubber. The addition of nano-titanium dioxide can also improve the flame retardant properties of the liquid silicone rubber product.

[0034] 2. In the liquid silicone rubber composition of the present invention, the fumed silica is modified by dimethyldichlorosilane or trimethylchlorosilane. The modified silica can significantly improve the physical properties of the material, and exhibits excellent stability, reinforcement and thickening properties in the liquid silicone rubber composition, so that the vulcanized product has higher strength. At the same time, the addition of silica can also significantly improve the tensile strength, hardness, wear resistance and tear resistance of the liquid silicone rubber product after vulcanization.

[0035] 3. The base rubber of the liquid silicone rubber composition of the present invention is mainly composed of three parts: base rubber, cross-linking agent and catalyst. Precipitated aluminum hydroxide is used as a flame retardant, and aluminum hydroxide has resistance to ultraviolet aging and excellent thermal conductivity, so that the liquid silicone rubber composition has excellent flame retardant properties, anti-ultraviolet aging properties and thermal conductivity. At the same time, white carbon black can also enhance the flame retardant properties, and work with aluminum hydroxide to improve the flame retardant ability of the product after vulcanization. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present invention are described clearly and completely below. 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.

[0037] The present invention provides a high-strength liquid silicone rubber composition, which comprises the following raw materials in parts by weight:

[0038] 100.0 parts of vinyl-terminated silicone oil;

[0039] 30.0 to 45.0 parts of modified white carbon black;

[0040] 1.0 to 5.0 parts of modified nano titanium dioxide

[0041] 14.0 to 26.0 parts of aluminum hydroxide;

[0042] 7.0 to 9.0 parts of hydrogen silicone oil;

[0043] 1.0 to 5.0 parts of silane coupling agent;

[0044] 0.2 to 0.5 parts of catalyst;

[0045] Among them, the modified white carbon black is prepared by gas phase method and modified by dimethyldichlorosilane or trimethylchlorosilane, and the modified nano titanium dioxide is prepared by surface silicon deposition method; the particle size of the white carbon black prepared by gas phase method is 5nm~50nm, and the BET specific surface area of ​​the white carbon black prepared by gas phase method is 300m 2 / g~400m2 / g.

[0046] The preparation method of modified nano titanium dioxide is as follows: immerse nano titanium dioxide in a hexane solvent of methyl silicone oil, stir evenly, evaporate and dry, and finally calcine in a muffle furnace at high temperature, calcine at 700°C for 2 hours to obtain modified nano titanium dioxide powder.

[0047] The components of the liquid silicone rubber composition also include an activator, which is zinc oxide and stearic acid. The activator includes 4.0 to 7.0 parts of zinc oxide and 0.75 to 1.25 parts of stearic acid in parts by weight.

[0048] The BET specific surface area of ​​aluminum hydroxide is 10 m 2 / g~20m 2 / g, and the particle size of aluminum hydroxide is 1um~10um.

[0049] The silane coupling agent is Si-69 silane coupling agent.

[0050] The catalyst is a platinum catalyst, and the content of the platinum catalyst is 10ppm to 25ppm.

[0051] The platinum catalyst is one of treated platinum, platinum black, chloroplatinic acid, ethanol-modified chloroplatinic acid, chloroplatinic acid / olefin complex and chloroplatinic acid / olefin siloxane complex.

[0052] The components of the liquid silicone rubber composition further include one or more of a vulcanizing agent, a vulcanization accelerator, an antioxidant and a plasticizer.

[0053] The present invention provides a method for preparing a high-strength liquid silicone rubber composition, comprising the following steps:

[0054] Step S1: weigh the components according to weight;

[0055] Step S2: adding the weighed vinyl-terminated silicone oil into a mixing box and stirring, then adding modified white carbon black and modified nano titanium dioxide, and stirring with a stirrer;

[0056] Step S3: adding the weighed aluminum hydroxide, silane coupling agent and activator into the mixing box and stirring to obtain a basic rubber material, and the stirring time is 10 minutes in total;

[0057] Step S4: taking out half of the base rubber prepared in step S3, adding weighed hydrogen-containing silicone oil and platinum catalyst to the taken out base rubber, and stirring evenly to obtain a mixed rubber;

[0058] Step S5: Evenly mix the mixed rubber obtained in the above step S4 and the remaining half of the base rubber obtained in the above step S3 to obtain a high-strength liquid silicone rubber composition.

[0059] The rotation speed of the stirrer is set to 2000 rpm, the stirring time of step S2 is set to 2 min, the stirring time of step S3 is set to 8 min, the stirring time of step S4 is set to 6 min, and the stirring time of step S5 is set to 5 min. The stirring operations are all carried out at a temperature of 25 to 35 °C.

[0060] Embodiment 1:

[0061] The present invention provides a high-strength liquid silicone rubber composition, which comprises the following raw materials in parts by weight:

[0062] 100.0 parts of vinyl-terminated silicone oil;

[0063] 40 parts of modified silica;

[0064] 2 parts of modified nano titanium dioxide

[0065] 20 parts of aluminum hydroxide;

[0066] 7 parts of hydrogen silicone oil;

[0067] Silane coupling agent 4 parts;

[0068] 0.35 parts of catalyst;

[0069] The modified silica is prepared by gas phase method and modified by dimethyldichlorosilane, and the modified nano titanium dioxide is prepared by surface silicon deposition. The particle size of the silica prepared by gas phase method is 35nm, and the BET specific surface area of ​​the silica prepared by gas phase method is 300m 2 / g.

[0070] The preparation method of modified nano titanium dioxide is as follows: immerse nano titanium dioxide in a hexane solvent of methyl silicone oil, stir evenly, evaporate and dry, and finally calcine in a muffle furnace at high temperature, calcine at 700°C for 2 hours to obtain modified nano titanium dioxide powder.

[0071] The components of the liquid silicone rubber composition also include an activator, which is zinc oxide and stearic acid. The activator includes 5 parts of zinc oxide and 1 part of stearic acid in parts by weight.

[0072] The BET specific surface area of ​​aluminum hydroxide is 15 m 2 / g, and the particle size of aluminum hydroxide is 8um.

[0073] The silane coupling agent is Si-69 silane coupling agent.

[0074] The catalyst is a platinum catalyst, and the content of the platinum catalyst is 18 ppm.

[0075] The platinum catalyst is a treated chloroplatinic acid / olefin complex.

[0076] The components of the liquid silicone rubber composition also include a vulcanizing agent and a vulcanization accelerator.

[0077] The present invention provides a method for preparing a high-strength liquid silicone rubber composition, comprising the following steps:

[0078] Step S1: weigh the components according to weight;

[0079] Step S2: adding the weighed vinyl-terminated silicone oil into a mixing box and stirring, then adding modified white carbon black and modified nano titanium dioxide, and stirring with a stirrer;

[0080] Step S3: adding the weighed aluminum hydroxide, silane coupling agent and activator into the mixing box and stirring to obtain a basic rubber material, and the stirring time is 10 minutes in total;

[0081] Step S4: taking out half of the base rubber prepared in step S3, adding weighed hydrogen-containing silicone oil and platinum catalyst to the taken out base rubber, and stirring evenly to obtain a mixed rubber;

[0082] Step S5: Evenly mix the mixed rubber obtained in the above step S4 and the remaining half of the base rubber obtained in the above step S3 to obtain a high-strength liquid silicone rubber composition.

[0083] The rotation speed of the stirrer is set to 2000 rpm, the stirring time of step S2 is set to 2 min, the stirring time of step S3 is set to 8 min, the stirring time of step S4 is set to 6 min, and the stirring time of step S5 is set to 5 min. The stirring operations are all carried out at a temperature of 25 to 35 °C.

[0084] Embodiment 2:

[0085] The present invention provides a high-strength liquid silicone rubber composition, which comprises the following raw materials in parts by weight:

[0086] 100.0 parts of vinyl-terminated silicone oil;

[0087] 35 parts of modified silica;

[0088] 3 parts of modified nano titanium dioxide

[0089] 15 parts of aluminum hydroxide;

[0090] 8 parts of hydrogen silicone oil;

[0091] Silane coupling agent 4 parts;

[0092] 0.35 parts of catalyst;

[0093] Among them, the modified silica is prepared by gas phase method and modified by dimethyldichlorosilane, and the modified nano titanium dioxide is prepared by surface silicon deposition method; the particle size of the silica prepared by gas phase method is 10nm, and the BET specific surface area of ​​the silica prepared by gas phase method is 320m 2 / g.

[0094] The preparation method of modified nano titanium dioxide is as follows: immerse nano titanium dioxide in a hexane solvent of methyl silicone oil, stir evenly, evaporate and dry, and finally calcine in a muffle furnace at high temperature, calcine at 700°C for 2 hours to obtain modified nano titanium dioxide powder.

[0095] The components of the liquid silicone rubber composition also include an activator, which is zinc oxide and stearic acid. The activator includes 4.5 parts of zinc oxide and 0.8 parts of stearic acid in parts by weight.

[0096] The BET specific surface area of ​​aluminum hydroxide is 16 m 2 / g, and the particle size of aluminum hydroxide is 8um.

[0097] The silane coupling agent is Si-69 silane coupling agent.

[0098] The catalyst is a platinum catalyst, and the content of the platinum catalyst is 22 ppm.

[0099] The platinum catalyst is treated platinum black.

[0100] The components of the liquid silicone rubber composition also include a vulcanizing agent and a vulcanization accelerator.

[0101] The present invention provides a method for preparing a high-strength liquid silicone rubber composition, comprising the following steps:

[0102] Step S1: weigh the components according to weight;

[0103] Step S2: adding the weighed vinyl-terminated silicone oil into a mixing box and stirring, then adding modified white carbon black and modified nano titanium dioxide, and stirring with a stirrer;

[0104] Step S3: adding the weighed aluminum hydroxide, silane coupling agent and activator into the mixing box and stirring to obtain a basic rubber material, and the stirring time is 10 minutes in total;

[0105] Step S4: taking out half of the base rubber prepared in step S3, adding weighed hydrogen-containing silicone oil and platinum catalyst to the taken out base rubber, and stirring evenly to obtain a mixed rubber;

[0106] Step S5: Evenly mix the mixed rubber obtained in the above step S4 and the remaining half of the base rubber obtained in the above step S3 to obtain a high-strength liquid silicone rubber composition.

[0107] The rotation speed of the stirrer is set to 2000 rpm, the stirring time of step S2 is set to 2 min, the stirring time of step S3 is set to 8 min, the stirring time of step S4 is set to 6 min, and the stirring time of step S5 is set to 5 min. The stirring operations are all carried out at a temperature of 25 to 35 °C.

[0108] Embodiment three:

[0109] The present invention provides a high-strength liquid silicone rubber composition, which comprises the following raw materials in parts by weight:

[0110] 100.0 parts of vinyl-terminated silicone oil;

[0111] 40 parts of modified silica;

[0112] 1.5 parts of modified nano titanium dioxide

[0113] 15 parts of aluminum hydroxide;

[0114] 8 parts of hydrogen silicone oil;

[0115] Silane coupling agent 4 parts;

[0116] 0.35 parts of catalyst;

[0117] Among them, the modified silica is prepared by gas phase method and modified by dimethyldichlorosilane, and the modified nano titanium dioxide is prepared by surface silicon deposition method; the particle size of the silica prepared by gas phase method is 45nm, and the BET specific surface area of ​​the silica prepared by gas phase method is 360m 2 / g.

[0118] The preparation method of modified nano titanium dioxide is as follows: immerse nano titanium dioxide in a hexane solvent of methyl silicone oil, stir evenly, evaporate and dry, and finally calcine in a muffle furnace at high temperature, calcine at 700°C for 2 hours to obtain modified nano titanium dioxide powder.

[0119] The components of the liquid silicone rubber composition also include an activator, which is zinc oxide and stearic acid. The activator includes 6 parts of zinc oxide and 1.2 parts of stearic acid in parts by weight.

[0120] The BET specific surface area of ​​aluminum hydroxide is 12 m 2 / g, and the particle size of aluminum hydroxide is 7um.

[0121] The silane coupling agent is Si-69 silane coupling agent.

[0122] The catalyst is a platinum catalyst, and the content of the platinum catalyst is 20 ppm.

[0123] The platinum catalyst was chloroplatinic acid modified with ethanol.

[0124] The components of the liquid silicone rubber composition also include a vulcanizing agent, a vulcanization accelerator and an antioxidant.

[0125] The present invention provides a method for preparing a high-strength liquid silicone rubber composition, comprising the following steps:

[0126] Step S1: weigh the components according to weight;

[0127] Step S2: adding the weighed vinyl-terminated silicone oil into a mixing box and stirring, then adding modified white carbon black and modified nano titanium dioxide, and stirring with a stirrer;

[0128] Step S3: adding the weighed aluminum hydroxide, silane coupling agent and activator into the mixing box and stirring to obtain a basic rubber material, and the stirring time is 10 minutes in total;

[0129] Step S4: taking out half of the base rubber prepared in step S3, adding weighed hydrogen-containing silicone oil and platinum catalyst to the taken out base rubber, and stirring evenly to obtain a mixed rubber;

[0130] Step S5: Evenly mix the mixed rubber obtained in the above step S4 and the remaining half of the base rubber obtained in the above step S3 to obtain a high-strength liquid silicone rubber composition.

[0131] The rotation speed of the stirrer is set to 2000 rpm, the stirring time of step S2 is set to 2 min, the stirring time of step S3 is set to 8 min, the stirring time of step S4 is set to 6 min, and the stirring time of step S5 is set to 5 min. The stirring operations are all carried out at a temperature of 25 to 35 °C.

[0132] Embodiment 4:

[0133] The present invention provides a high-strength liquid silicone rubber composition, which comprises the following raw materials in parts by weight:

[0134] 100.0 parts of vinyl-terminated silicone oil;

[0135] 38 parts of modified silica;

[0136] 3 parts of modified nano titanium dioxide

[0137] 15 parts of aluminum hydroxide;

[0138] 8 parts of hydrogen silicone oil;

[0139] Silane coupling agent 4 parts;

[0140] 0.35 parts of catalyst;

[0141] The modified silica is prepared by gas phase method by modifying trimethylchlorosilane, and the modified nano titanium dioxide is prepared by surface silicon deposition. The particle size of the silica prepared by gas phase method is 35nm, and the BET specific surface area of ​​the silica prepared by gas phase method is 350m 2 / g.

[0142] The preparation method of modified nano titanium dioxide is as follows: immerse nano titanium dioxide in a hexane solvent of methyl silicone oil, stir evenly, evaporate and dry, and finally calcine in a muffle furnace at high temperature, calcine at 700°C for 2 hours to obtain modified nano titanium dioxide powder.

[0143] The components of the liquid silicone rubber composition also include an activator, which is zinc oxide and stearic acid. The activator includes 7 parts of zinc oxide and 1 part of stearic acid in parts by weight.

[0144] The BET specific surface area of ​​aluminum hydroxide is 16 m 2 / g, and the particle size of aluminum hydroxide is 6um.

[0145] The silane coupling agent is Si-69 silane coupling agent.

[0146] The catalyst is a platinum catalyst, and the content of the platinum catalyst is 16 ppm.

[0147] The platinum catalyst was chloroplatinic acid.

[0148] The components of the liquid silicone rubber composition also include a vulcanizing agent, a vulcanization accelerator and an antioxidant.

[0149] The present invention provides a method for preparing a high-strength liquid silicone rubber composition, comprising the following steps:

[0150] Step S1: weigh the components according to weight;

[0151] Step S2: adding the weighed vinyl-terminated silicone oil into a mixing box and stirring, then adding modified white carbon black and modified nano titanium dioxide, and stirring with a stirrer;

[0152] Step S3: adding the weighed aluminum hydroxide, silane coupling agent and activator into the mixing box and stirring to obtain a basic rubber material, and the stirring time is 10 minutes in total;

[0153] Step S4: taking out half of the base rubber prepared in step S3, adding weighed hydrogen-containing silicone oil and platinum catalyst to the taken out base rubber, and stirring evenly to obtain a mixed rubber;

[0154] Step S5: Evenly mix the mixed rubber obtained in the above step S4 and the remaining half of the base rubber obtained in the above step S3 to obtain a high-strength liquid silicone rubber composition.

[0155] The rotation speed of the stirrer is set to 2000 rpm, the stirring time of step S2 is set to 2 min, the stirring time of step S3 is set to 8 min, the stirring time of step S4 is set to 6 min, and the stirring time of step S5 is set to 5 min. The stirring operations are all carried out at a temperature of 25 to 35 °C.

[0156] Comparative Example 1:

[0157] This comparative example provides a high-strength liquid silicone rubber composition, which comprises the following raw materials in parts by weight:

[0158] 100 parts of vinyl-terminated silicone oil;

[0159] 2 parts of modified nano titanium dioxide

[0160] 15 parts of aluminum hydroxide;

[0161] 7 parts of hydrogen silicone oil;

[0162] Silane coupling agent 4 parts;

[0163] 0.35 parts of catalyst;

[0164] Among them, the modified nano titanium dioxide is modified by a surface silicon deposition method. The preparation method of the modified nano titanium dioxide is as follows: the nano titanium dioxide is immersed in a n-hexane solvent of methyl silicone oil, stirred evenly, evaporated and dried, and finally high-temperature calcined in a muffle furnace at 700°C for 2 hours to obtain the modified nano titanium dioxide powder.

[0165] The components of the liquid silicone rubber composition also include an activator, which is zinc oxide and stearic acid. The activator includes 5 parts of zinc oxide and 1 part of stearic acid in parts by weight.

[0166] The BET specific surface area of ​​aluminum hydroxide is 15 m2 / g, and the particle size of aluminum hydroxide is 8 um.

[0167] The silane coupling agent is Si-69 silane coupling agent.

[0168] The catalyst is a platinum catalyst, and the content of the platinum catalyst is 18 ppm.

[0169] The platinum catalyst is a treated chloroplatinic acid / olefin complex.

[0170] The components of the liquid silicone rubber composition also include a vulcanizing agent and a vulcanization accelerator.

[0171] The present comparative example provides a method for preparing a high-strength liquid silicone rubber composition, comprising the following steps:

[0172] Step S1: weigh the components according to weight;

[0173] Step S2: adding the weighed vinyl-terminated silicone oil into a mixing box and stirring, then adding the modified silica and stirring with a stirrer;

[0174] Step S3: adding the weighed aluminum hydroxide, silane coupling agent and activator into the mixing box and stirring to obtain a basic rubber material, and the stirring time is 10 minutes in total;

[0175] Step S4: taking out half of the base rubber prepared in step S3, adding weighed hydrogen-containing silicone oil and platinum catalyst to the taken out base rubber, and stirring evenly to obtain a mixed rubber;

[0176] Step S5: Evenly mix the mixed rubber obtained in the above step S4 and the remaining half of the base rubber obtained in the above step S3 to obtain a high-strength liquid silicone rubber composition.

[0177] The rotation speed of the stirrer is set to 2000 rpm, the stirring time of step S2 is set to 2 min, the stirring time of step S3 is set to 8 min, the stirring time of step S4 is set to 6 min, and the stirring time of step S5 is set to 5 min. The stirring operations are all carried out at a temperature of 25 to 35 °C.

[0178] The content of this comparative example 1 is different from that of Example 1 in that: modified white carbon black is not added to the raw materials of this comparative example, and the rest is the same as that of Example 1.

[0179] Comparative Example 2:

[0180] This comparative example provides a high-strength liquid silicone rubber composition, which comprises the following raw materials in parts by weight:

[0181] 100.0 parts of vinyl-terminated silicone oil;

[0182] 40 parts of modified silica;

[0183] 20 parts of aluminum hydroxide;

[0184] 7 parts of hydrogen silicone oil;

[0185] Silane coupling agent 4 parts;

[0186] 0.35 parts of catalyst;

[0187] The modified silica is prepared by modifying dimethyldichlorosilane with silica prepared by the gas phase method. The particle size of the silica prepared by the gas phase method is 35 nm, and the BET specific surface area of ​​the silica prepared by the gas phase method is 300 m 2 / g.

[0188] The components of the liquid silicone rubber composition also include an activator, which is zinc oxide and stearic acid. The activator includes 5 parts of zinc oxide and 1 part of stearic acid in parts by weight.

[0189] The BET specific surface area of ​​aluminum hydroxide is 15 m 2 / g, and the particle size of aluminum hydroxide is 8um.

[0190] The silane coupling agent is Si-69 silane coupling agent.

[0191] The catalyst is a platinum catalyst, and the content of the platinum catalyst is 18 ppm.

[0192] The platinum catalyst is a treated chloroplatinic acid / olefin complex.

[0193] The components of the liquid silicone rubber composition also include a vulcanizing agent and a vulcanization accelerator.

[0194] The present comparative example provides a method for preparing a high-strength liquid silicone rubber composition, comprising the following steps:

[0195] Step S1: weigh the components according to weight;

[0196] Step S2: adding the weighed vinyl-terminated silicone oil into a mixing box and stirring, then adding the modified silica and stirring with a stirrer;

[0197] Step S3: adding the weighed aluminum hydroxide, silane coupling agent and activator into the mixing box and stirring to obtain a basic rubber material, and the stirring time is 10 minutes in total;

[0198] Step S4: taking out half of the base rubber prepared in step S3, adding weighed hydrogen-containing silicone oil and platinum catalyst to the taken out base rubber, and stirring evenly to obtain a mixed rubber;

[0199] Step S5: Evenly mix the mixed rubber obtained in the above step S4 and the remaining half of the base rubber obtained in the above step S3 to obtain a high-strength liquid silicone rubber composition.

[0200] The rotation speed of the stirrer is set to 2000 rpm, the stirring time of step S2 is set to 2 min, the stirring time of step S3 is set to 8 min, the stirring time of step S4 is set to 6 min, and the stirring time of step S5 is set to 5 min. The stirring operations are all carried out at a temperature of 25 to 35 °C.

[0201] The content of this comparative example 2 is different from that of Example 1 in that: the raw materials of this comparative example do not contain modified nano titanium dioxide, and the rest are the same as those of Example 1.

[0202] Comparative Example 3:

[0203] This comparative example provides a high-strength liquid silicone rubber composition, which comprises the following raw materials in parts by weight:

[0204] 100.0 parts of vinyl-terminated silicone oil;

[0205] 40 parts of modified silica;

[0206] 20 parts of modified nano titanium dioxide

[0207] 20 parts of aluminum hydroxide;

[0208] 7 parts of hydrogen silicone oil;

[0209] Silane coupling 4 parts;

[0210] 0.2 to 0.5 parts of catalyst;

[0211] The modified silica is prepared by gas phase method and modified by dimethyldichlorosilane, and the modified nano titanium dioxide is prepared by surface silicon deposition. The particle size of the silica prepared by gas phase method is 35nm, and the BET specific surface area of ​​the silica prepared by gas phase method is 300m 2 / g.

[0212] The preparation method of modified nano titanium dioxide is as follows: immerse nano titanium dioxide in a hexane solvent of methyl silicone oil, stir evenly, evaporate and dry, and finally calcine in a muffle furnace at high temperature, calcine at 700°C for 2 hours to obtain modified nano titanium dioxide powder.

[0213] The components of the liquid silicone rubber composition also include an activator, which is zinc oxide and stearic acid. The activator includes 5 parts of zinc oxide and 1 part of stearic acid in parts by weight.

[0214] The BET specific surface area of ​​aluminum hydroxide is 15 m 2 / g, and the particle size of aluminum hydroxide is 8um.

[0215] The silane coupling agent is Si-75 silane coupling agent.

[0216] The catalyst is a platinum catalyst, and the content of the platinum catalyst is 18 ppm.

[0217] The platinum catalyst is a treated chloroplatinic acid / olefin complex.

[0218] The components of the liquid silicone rubber composition also include a vulcanizing agent and a vulcanization accelerator.

[0219] The present comparative example provides a method for preparing a high-strength liquid silicone rubber composition, comprising the following steps:

[0220] Step S1: weigh the components according to weight;

[0221] Step S2: adding the weighed vinyl-terminated silicone oil into a mixing box and stirring, then adding modified white carbon black and modified nano titanium dioxide, and stirring with a stirrer;

[0222] Step S3: adding the weighed aluminum hydroxide, silane coupling agent and activator into the mixing box and stirring to obtain a basic rubber material, and the stirring time is 10 minutes in total;

[0223] Step S4: taking out half of the base rubber prepared in step S3, adding weighed hydrogen-containing silicone oil and platinum catalyst to the taken out base rubber, and stirring evenly to obtain a mixed rubber;

[0224] Step S5: Evenly mix the mixed rubber obtained in the above step S4 and the remaining half of the base rubber obtained in the above step S3 to obtain a high-strength liquid silicone rubber composition.

[0225] The rotation speed of the stirrer is set to 2000 rpm, the stirring time of step S2 is set to 2 min, the stirring time of step S3 is set to 8 min, the stirring time of step S4 is set to 6 min, and the stirring time of step S5 is set to 5 min. The stirring operations are all carried out at a temperature of 25 to 35 °C.

[0226] The content of this comparative example 3 is different from that of Example 1 in that the silane coupling agent used as the raw material of this comparative example is silane coupling agent Si-75, and the rest is the same as that of Example 1.

[0227] The following are the raw material manufacturers of this invention:

[0228] Vinyl-terminated silicone oil, Shandong Dayi silicone products;

[0229] R812S, a product of Evonik Industries, Germany;

[0230] 111LE; CTAB = 15m2 / g, Huber Bioproducts;

[0231] Hydrogenated silicone oil, a product of Shenzhen Lianhuan Silicone Co., Ltd.

[0232] Silane coupling agent Si-69; a product of Evonik Industries, Germany;

[0233] Silane coupling agent Si-75, Jiangxi Hongbai Industrial Products;

[0234] Zinc oxide, a product of Qingdao Haiyan Chemical Co., Ltd.;

[0235] Stearic acid, a product of Yihai Kerry;

[0236] Catalyst, product of Zhejiang Jiancheng Organic Silicone Co., Ltd.

[0237] The weight parts of the components of Examples 1-4 and Comparative Examples 1-3 are as follows:

[0238]

[0239] Performance test experiment:

[0240] The samples prepared in Examples 1-4 were subjected to a flat vulcanizing press with the temperature set to 110° C., the pressure set to 156 bar, and the time set to 20 min, and then vulcanized rubber strips with a size of 30 mm were prepared by compression molding and cutting;

[0241] Vulcanization curve: Weigh a certain amount of rubber, add hydrogenated silicone oil and platinum catalyst, mix well, and then use a rubber processing analyzer to test the isothermal vulcanization curves of different rubber samples. The test temperature is 110°C, the frequency is 1Hz, the torsion angle is 0.5°, and the test time is 20min.

[0242] Tensile properties: The tensile properties of the vulcanized rubber samples were tested using a solid rheometer with reference to GB / T528-2009, with a tensile rate of 3.33 mm / s.

[0243] Viscosity measurement: The viscosity of the base rubber was tested using a rubber processing analyzer in a dynamic time scanning mode with a test temperature of 40°C, a test frequency of 1 Hz, a torsion angle of 0.5°, and a test time of 15 min. The average value of the complex viscosity of 10 min to 15 min was taken as the viscosity of the rubber.

[0244] The performance test results of the above Examples 1-4 and Comparative Examples 1-3 are as follows:

[0245] Table 2

[0246]

[0247] Combined with the above implementation and comparative examples, and combined with the test results for analysis:

[0248] By comparing Examples 1-4 with Comparative Examples 1-3, the liquid silicone rubber composition samples prepared by the preparation scheme of the present invention have high physical strength after vulcanization, are convenient for injection molding, and have excellent tensile strength, hardness, wear resistance and tear resistance.

[0249] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A high-strength liquid silicone rubber composition, characterized in that: The rubber composition comprises the following raw materials by weight: 100.0 parts of vinyl-terminated silicone oil; 30.0 to 45.0 parts of modified white carbon black; 1.0 to 5.0 parts of modified nano titanium dioxide 14.0 to 26.0 parts of aluminum hydroxide; 7.0 to 9.0 parts of hydrogen silicone oil; 1.0 to 5.0 parts of silane coupling agent; 0.2 to 0.5 parts of catalyst; The modified white carbon black is prepared by gas phase method by modification of dimethyldichlorosilane or trimethylchlorosilane, and the modified nano titanium dioxide is prepared by surface silicon deposition; the particle size of the white carbon black prepared by gas phase method is 5nm-50nm, and the BET specific surface area of ​​the white carbon black prepared by gas phase method is 300m 2 / g~400m 2 / g.

2. A high-strength liquid silicone rubber composition according to claim 1, characterized in that: The preparation method of the modified nano titanium dioxide is as follows: immersing the nano titanium dioxide in a hexane solvent of methyl silicone oil, stirring evenly, evaporating and drying, and finally calcining in a muffle furnace at a high temperature of 700° C. for 2 hours to obtain the modified nano titanium dioxide powder.

3. A high-strength liquid silicone rubber composition according to claim 1, characterized in that: The components of the liquid silicone rubber composition also include an activator, which is zinc oxide and stearic acid. The activator includes 4.0 to 7.0 parts of zinc oxide and 0.75 to 1.25 parts of stearic acid in parts by weight.

4. A high-strength liquid silicone rubber composition according to claim 1, characterized in that: The BET specific surface area of ​​the aluminum hydroxide is 10 m 2 / g~20m 2 / g, and the particle size of aluminum hydroxide is 1um~10um.

5. A high-strength liquid silicone rubber composition and a preparation method thereof according to claim 1, characterized in that: The silane coupling agent is Si-69 silane coupling agent.

6. A high-strength liquid silicone rubber composition according to claim 1, characterized in that: The catalyst is a platinum catalyst, and the content of the platinum catalyst is 10ppm to 25ppm.

7. A high-strength liquid silicone rubber composition according to claim 6, characterized in that: The platinum catalyst is one of treated platinum, platinum black, chloroplatinic acid, ethanol-modified chloroplatinic acid, chloroplatinic acid / olefin complex and chloroplatinic acid / olefin siloxane complex.

8. The high-strength liquid silicone rubber composition according to claim 1, characterized in that: The components of the liquid silicone rubber composition also include one or more of a vulcanizing agent, a vulcanization accelerator, an antioxidant and a plasticizer.

9. A method for preparing a high-strength liquid silicone rubber composition, according to the high-strength liquid silicone rubber composition according to any one of claims 1 to 8, characterized in that: The steps include: Step S1: weigh the components according to weight; Step S2: adding the weighed vinyl-terminated silicone oil into a mixing box and stirring, then adding modified white carbon black and modified nano titanium dioxide, and stirring with a stirrer; Step S3: adding the weighed aluminum hydroxide, silane coupling agent and activator into the mixing box and stirring to obtain a basic rubber material, and the stirring time is 10 minutes in total; Step S4: taking out half of the base rubber prepared in step S3, adding weighed hydrogen-containing silicone oil and platinum catalyst to the taken out base rubber, and stirring evenly to obtain a mixed rubber; Step S5: Evenly mix the mixed rubber obtained in the above step S4 and the remaining half of the base rubber obtained in the above step S3 to obtain a high-strength liquid silicone rubber composition.

10. The method for preparing a high-strength liquid silicone rubber composition according to claim 9, characterized in that: The rotation speed of the stirrer is set to 2000 rpm, the stirring time of step S2 is set to 2 min, the stirring time of step S3 is set to 8 min, the stirring time of step S4 is set to 6 min, and the stirring time of step S5 is set to 5 min. The stirring operations are all performed at a temperature of 25-35°C.

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