Low-viscosity high-performance anti-settling conductive silicone rubber and preparation method thereof

Abstract

The invention discloses low-viscosity high-performance anti-settling conductive silicone rubber and a preparation method thereof, the low-viscosity high-performance anti-settling conductive silicone rubber is prepared from a base material, vinyl silicone resin, dimethyl silicone oil, hydrogen-containing silicone oil, an inhibitor and a platinum catalyst, and vinyl silicone oil, white carbon black, hexamethyldisilazane, a modified compound conductive filler and other materials are used in the base material; the modified compound conductive filler is nickel-plated graphite which is treated by tetramethyl divinyl disilazane and a powder modifier. The compound conductive filler is used and modified, so that the influence on the viscosity of the conductive silicone rubber is small, the anti-settling property is good, meanwhile, the addition amount of the white carbon black is reduced, and the conductive silicone rubber has relatively small volume resistivity, relatively high tensile strength and elongation at break, relatively low viscosity and excellent anti-settling property, namely the volume resistivity is less than or equal to 0.4 omega.cm; the tensile strength is greater than or equal to 4 MPa, the elongation at break is greater than 200%, the viscosity is less than 400 pa.s, and no obvious settlement is caused after the coating is stored at room temperature for 6 months.

Description

Technical Field

[0001] The invention belongs to the field of addition-type conductive silicone rubber, and in particular relates to low-viscosity, high-performance, anti-settling conductive silicone rubber and a preparation method thereof. Background Art

[0002] Addition conductive silicone rubber is a special organic silicon material that combines the advantages of conductive rubber and addition liquid silicone rubber. Compared with traditional conductive rubber, it has lower volume resistivity, better aging resistance and relatively simple processing technology. Due to its unique properties, this material is widely used in many fields such as electronics, medical treatment, and computers, and has become one of the indispensable materials in modern science and technology.

[0003] Addition conductive silicone rubber is composed of addition liquid silicone rubber matrix and conductive filler. The addition liquid silicone rubber matrix is ​​cross-linked with vinyl silicone oil and hydrogen silicone oil under platinum catalysis to form an elastomer to provide various basic properties for conductive silicone rubber. Conductive fillers are filled in the elastomer to form a conductive path. There are three main types of conductive fillers currently used, namely metal conductive fillers, carbon conductive fillers, and composite conductive fillers. Among them, metal conductive fillers include silver powder, copper powder, nickel powder, etc., which have excellent conductive properties, but poor economy and processability; carbon conductive fillers include carbon black, graphite, carbon fiber, etc., which are low in price and good in stability, but difficult to disperse and poor in conductivity; composite conductive fillers include silver-plated glass beads, nickel-plated graphite, nickel-plated graphene, etc., whose conductivity is better than ordinary carbon fillers and the price is also lower than metal fillers. Conductive silicone rubber with excellent performance can be obtained by rationally matching the liquid silicone rubber matrix and filler. However, the following problems will be encountered in actual production and processing: ① In order to obtain conductive silicone rubber with excellent conductive properties, a large amount of conductive filler needs to be added, resulting in excessively high costs; ② The conductive filler has a poor reinforcing effect on the colloid, and the prepared conductive glue has low tensile strength and elongation at break, which is easy to deform or break due to external forces during use, reducing the service life; ③ The untreated conductive filler has poor compatibility with the silicone system. After addition, the high viscosity affects the construction performance and is prone to sedimentation during storage.

[0004] Chinese patent document CN 111718672A discloses a high-performance organic silicon conductive shielding adhesive and its preparation method. It uses 50μm to 100μm nickel-coated graphite as a conductive filler, and reinforces the silicone rubber by adding single-walled carbon nanotubes, so that the volume resistivity of the conductive silicone reaches 60mΩ·cm, the tensile strength reaches more than 4.0MPa, and the elongation at break reaches more than 100%. However, the amount of conductive filler added is as high as 300 to 500 parts, which is too costly and not conducive to large-scale industrial use. In order to improve the tensile strength of the conductive shielding adhesive, the amount of white carbon black added is as high as 50 to 100 parts. The large amount of white carbon black added will significantly increase the viscosity of the system, affect the construction performance, and have a significant adverse effect on the conductivity. Secondly, the elongation at break is only 100%, and there is a risk of deformation and damage by external force when the product is used, which affects the service life.

[0005] Chinese patent publication number CN 105199623A discloses a two-component addition-type anti-settling conductive silicone and its preparation method. The conductive powder is modified by using a coupling agent, so that after the conductive glue is stored at a low temperature of 0 to 5°C for 6 months, the viscosity of the upper and lower layers changes little and there is no obvious sedimentation. Its disadvantage is that the coupling agents used, such as A-171 and A-174, have poor alkoxy groups on the low-activity hydroxyl groups on nickel-plated graphite, and the coupling agent chain is short, which has little effect on improving the compatibility of conductive fillers and silicone rubber, and there is a risk of sedimentation in low-viscosity silicone rubber systems. Summary of the invention

[0006] The purpose of the present invention is to provide a low-viscosity, high-performance, anti-settling conductive silicone rubber and a preparation method thereof, which is characterized by having a small volume resistivity, high tensile strength and elongation at break, low viscosity and excellent anti-settling performance, that is, the volume resistivity is ≤0.4Ω·cm, the tensile strength is ≥4MPa, the elongation at break is >200%, the viscosity is <400pa.s, and there is no obvious sedimentation when stored at room temperature for 6 months.

[0007] To achieve the above object, the present invention provides the following technical measures, wherein the raw materials are all in mass fractions.

[0008] The present invention provides a low-viscosity, high-performance, anti-settling conductive silicone rubber, which is made of raw materials including the following components:

[0009]

[0010] The raw material components of the base material are calculated by mass:

[0011]

[0012] Optionally, the vinyl silicone resin is a vinyl MQ silicone resin with a vinyl content of 2.3% to 3.2% and a chemical formula of [(CH3)2(CH2=CH)SiO 1 / 2 ] a [(CH3)3SiO 1 / 2 ] b [SiO 4 / 2 ] c , where the value of (a+b) / c is 0.6 to 0.9.

[0013] Optionally, the hydrogen-containing silicone oil is side hydrogen-containing silicone oil or end side hydrogen-containing silicone oil, and the hydrogen content is 0.18% to 1.60%.

[0014] Optionally, the viscosity of the vinyl silicone oil is 1000-20000 mPa.s at a temperature of 25° C. The viscosity of the vinyl silicone oil affects the final viscosity of the silicone rubber product, and within this range, silicone rubber with a viscosity of less than 400 Pa.s can be obtained.

[0015] Optionally, the white carbon black is precipitated white carbon black or fumed white carbon black, preferably fumed white carbon black, and the specific surface area of ​​fumed white carbon black is 150 to 400 m 2 / g. White carbon black can strengthen the mechanical properties of silicone rubber products. White carbon black in this specific surface area range has good dispersion and reinforcement effects.

[0016] Optionally, the inhibitor is at least one of 3,7,11-trimethyldodecyn-3-ol, 3-methyl-1-butyn-3-ol, 1-ethynylcyclohexanol, and 3-phenyl-1-butyn-3-ol.

[0017] Optionally, the platinum catalyst is at least one of a platinum-divinyltetramethyldisiloxane complex, a bis(phenylethynyl)-1,5-dimethylcyclooctane-1,5-diene platinum complex, a bis(3-phenyl-1-butyn-3-ol)-cyclooctane-1,5-diene platinum complex, and a bis(1-ethynylcyclohexanol)-cyclooctane-1,5-diene platinum complex, wherein the platinum content is 1000 to 3000 ppm.

[0018] Optionally, the modified compound conductive filler is a composition composed of small-particle spherical nickel-plated graphite and large-particle flaky nickel-plated graphite treated with tetramethyl divinyl disilazane and powder modifier Y, wherein the particle size of the small-particle spherical nickel-plated graphite is 10 μm to 50 μm, the particle size of the large-particle flaky nickel-plated graphite is 50 μm to 200 μm, and the small-particle spherical nickel-plated graphite and the large-particle flaky nickel-plated graphite are both treated with tetramethyl divinyl disilazane and powder modifier Y. And the small-particle spherical nickel-plated graphite accounts for 10% to 42% wt in the modified compound conductive filler. When the small-particle spherical nickel-plated graphite accounts for too high a proportion in the modified compound conductive filler, the conductive performance of the conductive silicone rubber will deteriorate, and when the small-particle spherical nickel-plated graphite accounts for too low a proportion in the modified compound conductive filler, the viscosity of the conductive silicone rubber will increase, affecting the construction performance. Based on the consideration of the dual properties of conductivity and viscosity, the present invention sets the small-particle spherical nickel-plated graphite in the modified composite conductive filler to account for 10% to 42% wt. Preferably, the particle sizes of the small-particle spherical nickel-plated graphite and the large-particle flaky nickel-plated graphite are not equal to 50 μm at the same time.

[0019] Optionally, the powder modifier Y has the following structural formula:

[0020] In the formula, Z1 is a methoxy group or an ethoxy group, and n is a natural number of 5 to 30.

[0021] The preparation method of the above-mentioned powder modifier Y comprises the following steps:

[0022] (1) Add hydrogen-terminated silicone oil and platinum catalyst into a three-necked flask, stir evenly, and then slowly dropwise add vinyl siloxane to carry out a hydrosilylation reaction;

[0023] (2) Add activated carbon for adsorption, filter and distill under reduced pressure to obtain powder modifier Y.

[0024] Preferably, the preparation method of the above-mentioned powder modifier Y comprises the following steps:

[0025] (1) Add 0.11-0.33 mol of terminal hydrogen-containing silicone oil and 0.2 g of Custer platinum catalyst with a platinum concentration of 3000 ppm into a three-necked flask and stir evenly;

[0026] (2) slowly dropwise adding 0.1 to 0.3 mol of vinyl siloxane and heating to 50 to 80° C. to carry out a hydrosilylation reaction for 60 to 180 minutes;

[0027] (3) Add activated carbon for adsorption for 2 h to 6 h, filter, and distill under reduced pressure to obtain powder modifier Y.

[0028] The preparation method of the modified composite conductive filler comprises the following steps:

[0029] Add 120 to 200 parts by weight of flaky and spherical nickel-plated graphite, 35 to 50 parts by weight of tetramethyldivinyldisilazane, 5 to 10 parts by weight of water and 60 parts by weight of xylene to a three-necked flask according to a certain proportion, stir and reflux at 90° C. for at least 3 hours, stir and reflux at 120° C. for at least 2 hours, and then cool; filter after cooling, pour into a tray and spread flat, put into a vacuum oven and bake at 150° C. for at least 2 hours, and seal after cooling to obtain a composite powder treated with tetramethyldivinyldisilazane;

[0030] Add a composite powder treated with tetramethyldivinyldisilazane, 30 to 50 parts by mass of a powder modifier Y, 0.5 parts by mass of a platinum catalyst, and 60 parts by mass of xylene into a flask, stir and react at 50°C for at least 2 hours, filter and dry after cooling, wash with xylene at least three times, put it in a vacuum oven and bake it at 150°C for at least 2 hours, and obtain a modified composite conductive filler after cooling.

[0031] The present invention also provides a method for preparing the low-viscosity, high-performance, anti-settling conductive silicone rubber, which comprises the following steps:

[0032] (1) Preparation of base material:

[0033] 80 parts by mass of vinyl silicone oil, 15 to 30 parts by mass of fumed silica, 2 to 15 parts by mass of hexamethyldisilazane, and 2 to 10 parts by mass of water are stirred in a vacuum kneader for 60 to 180 minutes, then heated to 120° C. to 200° C. and stirred for 90 to 200 minutes, and after cooling, 120 to 200 parts by mass of a modified composite conductive filler are added, and then the mixture is blended for 60 to 180 minutes at a vacuum degree of -0.08 to -0.1 MPa, and then diluted, cooled, and ground to obtain a base material;

[0034] (2) Preparation of low-viscosity, high-performance, anti-settling conductive silicone rubber:

[0035] 100 parts by mass of base material, 5-15 parts by mass of vinyl silicone resin, 3-10 parts by mass of dimethyl silicone oil and 1-5 parts by mass of hydrogenated silicone oil are added into a planetary mixer with a cooling and high-speed dispersing device, stirred for 10-20 minutes at a high-speed dispersing speed of 500-1000 r / min and a low-speed stirring speed of 40-80 r / min, 0.1-1 parts by mass of inhibitor are added, stirred for 15-20 minutes at a high-speed dispersing speed of 300-600 r / min, a low-speed stirring speed of 30-60 r / min and a vacuum degree of -0.08 to -0.1 MPa, 0.1-1 parts by mass of platinum catalyst are added, stirred for 5-15 minutes at a high-speed dispersing speed of 300-600 r / min, a low-speed stirring speed of 30-60 r / min and a vacuum degree of -0.08 to -0.1 MPa, the material is discharged and sealed for storage to obtain a low-viscosity, high-performance, anti-settling conductive silicone rubber.

[0036] The working principle of the present invention is as follows:

[0037] The reaction equation for treating the composite nickel-plated graphite filler with tetramethyl divinyl disilazane and powder modifier Y is as follows:

[0038] (1) Hydrolysis of tetramethyldivinyldisilazane to vinylsilanol

[0039]

[0040] (2) Reaction of vinyl silanol with surface hydroxyl groups of nickel-coated graphite (NCG)

[0041]

[0042] (3) Introducing the siloxane chain segment (powder modifier Y) onto the powder surface. This reaction utilizes the vinyl group introduced into the powder surface by tetramethyldivinyldisilazane to react with the powder modifier Y:

[0043]

[0044] Tetramethyldivinyldisilazane is hydrolyzed into vinyl silanol, which reacts with the hydroxyl groups on the surface of nickel-plated graphite under high temperature conditions, so that the surface of the conductive filler powder carries more vinyl siloxane, wherein some of the vinyl siloxane on the powder surface reacts with the Si-H bond in the powder modifier Y to introduce long-chain -Si-0-Si-links and alkoxy groups into the powder surface, and some vinyl groups introduced by tetramethyldivinyldisilazane remain on the powder surface.

[0045] After the introduction of long-chain siloxane, the compatibility and dispersibility of the conductive filler with the organosilicon system are greatly improved, the effect on the viscosity of the silicone rubber is reduced, and it is not easy to settle. In addition, the hydroxyl groups on the surface of the conductive filler powder easily cause the powder to agglomerate, and the modified composite conductive filler prepared by the present invention has an alkoxy structure (Z1 on the modifier) ​​on the chain. The alkoxy structure reacts with the residual water in the silicone rubber system and hydrolyzes, and combines with a small amount of untreated hydroxyl groups on the surface of the conductive powder, avoiding the formation of hydrogen bonds between the powders to aggravate agglomeration, further preventing the powder from settling, and reducing the viscosity.

[0046] The conductive filler powder contains unreacted vinyl groups. When the rubber is cured, the vinyl MQ silicone resin added therein and the vinyl groups on the modified conductive filler can react and crosslink with the hydrogenated silicone oil to assist the reinforcement of white carbon black. Therefore, the rubber can still have good tensile strength and elongation at break while reducing the amount of white carbon black added.

[0047] Under the same size conditions, the conductivity of nickel-plated graphite in flake form is better than that in spherical form. However, flake nickel-plated graphite also has certain defects in use. Since it is easier to entangle or pile up with each other and is not easy to disperse, the viscosity of the silicone rubber system will increase significantly, and the uneven dispersion will affect the formation of the conductive network. The present invention uses a composite nickel-plated graphite filler composed of small-particle spherical nickel-plated graphite and large-particle flaky nickel-plated graphite to reduce the amount of conductive filler added while maintaining excellent conductivity. The strong shearing and dispersing effect of the kneading machine is then utilized to reduce the formation of conductive filler aggregates, so that the conductive filler is evenly dispersed in the silicone rubber to form a stable conductive network. Since white carbon black has a large negative impact on the formation of the conductive path of silicone rubber, the present invention reduces the amount of white carbon black added to increase the overall conductivity of the conductive silicone.

[0048] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0049] (1) The present invention uses a composite conductive filler and modifies it to have little effect on viscosity and good anti-settling property, while reducing the amount of white carbon black added and using a vinyl silicone resin with little effect on viscosity for reinforcement, so that the conductive silicone rubber has low viscosity (<400 Pa.s) and high workability, and can be stored at room temperature for 6 to 9 months without obvious sedimentation.

[0050] (2) The present invention uses vinyl silicone resin and modified conductive filler to assist in reinforcement, so that the conductive silicone rubber has good tensile strength and elongation at break, that is, tensile strength ≥ 4Mpa, elongation at break > 200%. In actual use, it is not easy to be deformed and damaged by external forces, and the product has a long service life.

[0051] (3) The present invention uses two types of nickel-plated graphites of different sizes for compound modification, and optimizes the proportion of each component of the conductive adhesive. While maintaining excellent conductivity, the amount of conductive filler added is reduced, thereby reducing the overall cost of the conductive silicone rubber. DETAILED DESCRIPTION

[0052] The present invention is specifically described below through examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments based on the contents of the present invention.

[0053] 1. Compounding of conductive fillers

[0054] Compound conductive filler①: 40 parts of 30μm spherical nickel-plated graphite and 120 parts of 150μm flake nickel-plated graphite.

[0055] Compound conductive filler ②: 50 parts of 30 μm spherical nickel-plated graphite and 110 parts of 120 μm flake nickel-plated graphite.

[0056] Compound conductive filler ③: 50 parts of 40 μm spherical nickel-plated graphite and 110 parts of 120 μm flake nickel-plated graphite.

[0057] Compound conductive filler④: 20 parts of 10μm spherical nickel-plated graphite, 180 parts of 60μm flake nickel-plated graphite.

[0058] Compound conductive filler ⑤: 50 parts of 50 μm spherical nickel-plated graphite and 70 parts of 200 μm flake nickel-plated graphite.

[0059] 2. Synthesis of powder modifier Y

[0060] Powder treatment agent Y1:

[0061] (1) Add 0.22 mol of end-hydrogenated silicone oil with a molecular weight of 500 and 0.2 g of Custer platinum catalyst with a platinum concentration of 3000 ppm into a three-necked flask and stir evenly;

[0062] (2) slowly adding 0.2 mol of vinyltrimethoxysilane to carry out a hydrosilylation reaction, heating to 60° C., and reacting for 90 min;

[0063] (3) Add activated carbon for adsorption for 4 h, filter, and distill under reduced pressure to obtain powder modifier Y1.

[0064] In the structural formula of powder modifier Y1, the value of n is 5 and Z1 is a methoxy group.

[0065] Powder treatment agent Y2:

[0066] (1) Add 0.22 mol of end-hydrogenated silicone oil with a molecular weight of 1000 and 0.2 g of Custer platinum catalyst with a platinum concentration of 3000 ppm into a three-necked flask and stir evenly;

[0067] (2) slowly adding 0.2 mol of vinyltrimethoxysilane to carry out a hydrosilylation reaction, heating to 60° C., and reacting for 90 min;

[0068] (3) Add activated carbon for adsorption for 4 h, filter, and distill under reduced pressure to obtain powder modifier Y2.

[0069] In the structural formula of powder modifier Y2, the value of n is 11 and Z1 is a methoxy group.

[0070] Powder treatment agent Y3:

[0071] (1) Add 0.22 mol of end-hydrogenated silicone oil with a molecular weight of 1000 and 0.2 g of Custer platinum catalyst with a platinum concentration of 3000 ppm into a three-necked flask and stir evenly;

[0072] (2) slowly adding 0.2 mol of vinyltriethoxysilane to carry out a hydrosilylation reaction, raising the temperature to 60° C., and reacting for 90 min;

[0073] (3) Add activated carbon for adsorption for 4 h, filter, and distill under reduced pressure to obtain powder modifier Y3.

[0074] In the structural formula of powder modifier Y3, the value of n is 11 and Z1 is an ethoxy group.

[0075] Powder treatment agent Y4:

[0076] (1) Add 0.22 mol of end-hydrogenated silicone oil with a molecular weight of 2500 and 0.2 g of Custer platinum catalyst with a platinum concentration of 3000 ppm into a three-necked flask and stir evenly;

[0077] (2) slowly adding 0.2 mol of vinyltrimethoxysilane to carry out a hydrosilylation reaction, heating to 60° C., and reacting for 90 min;

[0078] (3) Add activated carbon for adsorption for 4 h, filter, and distill under reduced pressure to obtain powder modifier Y4.

[0079] In the structural formula of powder modifier Y4, the value of n is 30 and Z1 is a methoxy group.

[0080] 3. Conductive Silicone Rubber Example

[0081] Embodiment 1:

[0082] (1) Add 160 parts of composite conductive filler ①, 40 parts of tetramethyldivinyldisilazane, 7 parts of water and 60 parts of xylene into a three-necked flask, stir and reflux at 90°C for 3 hours, stir and reflux at 120°C for 2 hours and then cool. After cooling, filter and pour into a tray and spread it flat, put it in a vacuum oven and bake it at 150°C for 2 hours. After cooling, seal it to obtain a composite powder treated with tetramethyldivinyldisilazane.

[0083] Add 160 parts of a composite powder treated with tetramethyldivinyldisilazane, 40 parts of a powder modifier Y1, 0.5 parts of a platinum catalyst, and 60 parts of xylene into a flask, stir and react at 50°C for 2 hours, filter and dry after cooling, wash three times with xylene, put into a vacuum oven and bake at 150°C for 2 hours, and obtain a modified composite conductive filler after cooling.

[0084] (2) 80 parts of vinyl silicone oil with a viscosity of 5000 mPa.s and a specific surface area of ​​350 m 225 parts of fumed silica of 1.347 W / g, 10 parts by mass of hexamethyldisilazane and 2 parts by mass of water are stirred in a vacuum kneader for 120 min, then heated to 120° C. and stirred for 100 min, and after cooling, 160 parts by mass of the modified composite conductive filler obtained in step (1) are added, and then the mixture is blended for 120 min at a vacuum degree of -0.08 to -0.1 MPa, and then diluted, cooled and ground to obtain a base material;

[0085] 100 parts of base material, 12 parts of vinyl MQ silicone resin with a vinyl content of 2.3%, 8 parts of dimethyl silicone oil, and 2.1 parts of side hydrogenated silicone oil with a hydrogen content of 0.75% are added into a planetary mixer with a cooling and high-speed dispersing device, and stirred for 15 minutes at a high-speed dispersing speed of 600 r / min and a low-speed stirring speed of 60 r / min. 0.1 part of 3-phenyl-1-butyn-3-ol is added, and stirred for 15 minutes at a high-speed dispersing speed of 500 r / min, a low-speed stirring speed of 50 r / min, and a vacuum degree of -0.08 to -0.1 MPa. 0.2 part of bis(3-phenyl-1-butyn-3-ol)-cyclooctane-1,5-diene platinum complex (3000ppm) is added, and stirred for 10 minutes at a high-speed dispersing speed of 500 r / min, a low-speed stirring speed of 50 r / min, and a vacuum degree of -0.08 to -0.1 MPa. The material is sealed and stored to obtain a low-viscosity, high-performance, anti-settling conductive silicone rubber.

[0086] Embodiment 2:

[0087] The preparation process is similar to that of Example 1, except that in step (1), compound conductive filler ② is used to replace compound conductive filler ①, and in step (2), 4 parts of side hydrogen-containing silicone oil with a hydrogen content of 0.36% are used to replace 2.1 parts of side hydrogen-containing silicone oil with a hydrogen content of 0.75%.

[0088] Embodiment 3:

[0089] The preparation process is similar to that of Example 1, except that in step (1), compound conductive filler ③ is used to replace compound conductive filler ①.

[0090] Embodiment 4:

[0091] The preparation process is similar to that of Example 1, except that in step (1), powder treatment agent Y2 is used to replace powder treatment agent Y1.

[0092] Embodiment 5:

[0093] The preparation process is similar to that of Example 1, except that in step (1), powder treatment agent Y3 is used to replace powder treatment agent Y1.

[0094] Embodiment 6:

[0095] The preparation process is similar to that of Example 1, except that in step (2), a vinyl MQ silicone resin with a vinyl content of 3.2% is used to replace a vinyl MQ silicone resin with a vinyl content of 2.3%, and a vinyl silicone oil with a viscosity of 15000 mPa.s is used to replace a vinyl silicone oil with a viscosity of 5000 mPa.s.

[0096] Embodiment 7:

[0097] (1) Add 200 parts of composite conductive filler ④, 50 parts of tetramethyldivinyldisilazane, 10 parts of water and 60 parts of xylene into a three-necked flask, stir and reflux at 90°C for 3 hours, stir and reflux at 120°C for 2 hours and then cool. After cooling, filter and pour into a tray and spread it flat, put it in a vacuum oven and bake it at 150°C for 2 hours. After cooling, seal it to obtain a composite powder treated with tetramethyldivinyldisilazane.

[0098] Add 200 parts of compound powder treated with tetramethyldivinyldisilazane, 50 parts of powder modifier Y4, 0.5 parts of platinum catalyst, and 60 parts of xylene into a flask, stir and react at 50°C for 2 hours, filter and dry after cooling, wash three times with xylene, put into a vacuum oven and bake at 150°C for 2 hours, and obtain the modified compound conductive filler after cooling.

[0099] (2) 80 parts of vinyl silicone oil with a viscosity of 5000 mPa.s and a specific surface area of ​​350 m 2 30 parts by weight of fumed silica, 15 parts by weight of hexamethyldisilazane and 10 parts by weight of water are stirred in a vacuum kneader for 120 minutes, then heated to 120° C. and stirred for 100 minutes, and after cooling, 200 parts by weight of the modified composite conductive filler obtained in step (1) are added, and then the mixture is blended for 120 minutes at a vacuum degree of -0.08 to -0.1 MPa, and then diluted, cooled and ground to obtain a base material;

[0100] 100 parts of base material, 5 parts of vinyl MQ silicone resin with a vinyl content of 3.2%, 10 parts of dimethyl silicone oil, and 1 part of side hydrogenated silicone oil with a hydrogen content of 1.25% are added into a planetary mixer with a cooling and high-speed dispersing device, and stirred for 15 minutes at a high-speed dispersing speed of 600 r / min and a low-speed stirring speed of 60 r / min. 0.2 parts of 3-methyl-1-butyn-3-ol are added, and stirred for 15 minutes at a high-speed dispersing speed of 500 r / min, a low-speed stirring speed of 50 r / min, and a vacuum degree of -0.08 to -0.1 MPa. 0.4 parts of bis(1-ethynylcyclohexanol)-cyclooctane-1,5-diene platinum complex (3000ppm) are added, and stirred for 10 minutes at a high-speed dispersing speed of 500 r / min, a low-speed stirring speed of 50 r / min, and a vacuum degree of -0.08 to -0.1 MPa. The material is sealed and stored to obtain a low-viscosity, high-performance, anti-sedimentation conductive silicone rubber.

[0101] Embodiment 8:

[0102] (1) Add 120 parts of composite conductive filler ⑤, 35 parts of tetramethyldivinyldisilazane, 5 parts of water and 60 parts of xylene into a three-necked flask, stir and reflux at 90°C for 3 hours, stir and reflux at 120°C for 2 hours and then cool, filter and pour into a tray after cooling, spread it flat, put it in a vacuum oven and bake it at 150°C for 2 hours, cool it and seal it to obtain a composite powder treated with tetramethyldivinyldisilazane.

[0103] Add 120 parts of compound powder treated with tetramethyldivinyldisilazane, 30 parts of powder modifier Y4, 0.5 parts of platinum catalyst, and 60 parts of xylene into a flask, stir and react at 50°C for 2 hours, filter and dry after cooling, wash three times with xylene, put into a vacuum oven and bake at 150°C for 2 hours, and obtain a modified compound conductive filler after cooling.

[0104] (2) 80 parts of vinyl silicone oil with a viscosity of 20000 mPa.s and a specific surface area of ​​350 m 2 15 parts of fumed silica of 1.377 W / g, 2 parts by mass of hexamethyldisilazane and 2 parts by mass of water are stirred in a vacuum kneader for 120 min, then heated to 120° C. and stirred for 100 min, and after cooling, 120 parts by mass of the modified composite conductive filler obtained in step (1) are added, and then the mixture is blended for 120 min at a vacuum degree of -0.08 to -0.1 MPa, and then diluted, cooled and ground to obtain a base material;

[0105] 100 parts of base material, 15 parts of vinyl MQ silicone resin with a vinyl content of 2.8%, 3 parts of dimethyl silicone oil, and 5 parts of side hydrogenated silicone oil with a hydrogen content of 0.45% are added into a planetary mixer with a cooling and high-speed dispersing device, and stirred for 15 minutes at a high-speed dispersing speed of 600 r / min and a low-speed stirring speed of 60 r / min. 0.1 parts of 1-ethynylcyclohexanol are added, and stirred for 15 minutes at a high-speed dispersing speed of 500 r / min, a low-speed stirring speed of 50 r / min, and a vacuum degree of -0.08 to -0.1 MPa. 0.4 parts of bis(1-ethynylcyclohexanol)-cyclooctane-1,5-diene platinum complex (3000 ppm) are added, and stirred for 10 minutes at a high-speed dispersing speed of 500 r / min, a low-speed stirring speed of 50 r / min, and a vacuum degree of -0.08 to -0.1 MPa. The material is sealed and stored to obtain a low-viscosity, high-performance, anti-sedimentation conductive silicone rubber.

Claims

1. A low-viscosity, high-performance, anti-settling conductive silicone rubber, characterized in that: The raw materials are made of the following ingredients measured by weight: The raw material components of the base material are calculated by mass:

2. The low-viscosity, high-performance, anti-settling conductive silicone rubber according to claim 1, characterized in that: The modified composite conductive filler is nickel-plated graphite treated with tetramethyldivinyldisilazane and powder modifier Y; The structural formula of powder modifier Y is as follows: In the formula, Z1 is a methoxy group or an ethoxy group, and n is a natural number of 5 to 30.

3. The low-viscosity, high-performance, anti-settling conductive silicone rubber according to claim 2, characterized in that: The nickel-plated graphite is a composition of small-particle spherical nickel-plated graphite and large-particle flaky nickel-plated graphite, wherein the particle size of the small-particle spherical nickel-plated graphite is 10μm-50μm, the particle size of the large-particle flaky nickel-plated graphite is 50μm-200μm, and the small-particle spherical nickel-plated graphite accounts for 10%-42%wt in the modified composite conductive filler.

4. The low-viscosity, high-performance, anti-settling conductive silicone rubber according to claim 2 or 3, characterized in that: The preparation method of the modified composite conductive filler comprises the following steps: Add 120 to 200 parts by weight of flaky and spherical nickel-plated graphite into a three-necked flask, add 35 to 50 parts by weight of tetramethyldivinyldisilazane, 5 to 10 parts by weight of water and 60 parts by weight of xylene, stir and reflux at 90° C. for at least 3 hours, stir and reflux at 120° C. for at least 2 hours, and then cool; filter after cooling, pour into a tray, spread flat, vacuum bake, and seal after cooling to obtain a composite powder treated with tetramethyldivinyldisilazane; Add a composite powder treated with tetramethyldivinyldisilazane, 30 to 50 parts by mass of a powder modifier Y, 0.5 parts by mass of a platinum catalyst, and 60 parts by mass of xylene into a flask, stir and react at 50°C for at least 2 hours, filter and dry after cooling, wash with xylene, and vacuum bake to obtain a modified composite conductive filler after cooling.

5. The low-viscosity, high-performance, anti-settling conductive silicone rubber according to claim 2 or 3, characterized in that: The vinyl silicone resin is a vinyl MQ silicone resin with a vinyl content of 2.3% to 3.2%.

6. The low-viscosity, high-performance, anti-settling conductive silicone rubber according to claim 5, characterized in that: The hydrogen-containing silicone oil is side hydrogen-containing silicone oil or end side hydrogen-containing silicone oil, and the hydrogen content is 0.18% to 1.60%.

7. The low-viscosity, high-performance, anti-settling conductive silicone rubber according to claim 6, characterized in that: The viscosity of the vinyl silicone oil is 1000-20000 mPa.s at a temperature of 25°C; the white carbon black is fumed white carbon black, and the specific surface area of ​​the fumed white carbon black is 150-400 m 2 / g.

8. The low-viscosity, high-performance, anti-settling conductive silicone rubber according to claim 7, characterized in that: The inhibitor is at least one of 3,7,11-trimethyldodecene-3-ol, 3-methyl-1-butyn-3-ol, 1-ethynylcyclohexanol, and 3-phenyl-1-butyn-3-ol.

9. The low-viscosity, high-performance, anti-settling conductive silicone rubber according to claim 8, characterized in that: The platinum catalyst is at least one of a platinum-divinyltetramethyldisiloxane complex, a bis(phenylethynyl)-1,5-dimethylcyclooctane-1,5-diene platinum complex, a bis(3-phenyl-1-butyn-3-ol)-cyclooctane-1,5-diene platinum complex, and a bis(1-ethynylcyclohexanol)-cyclooctane-1,5-diene platinum complex, wherein the platinum content is 1000 to 3000 ppm.

10. The method for preparing the low-viscosity, high-performance, anti-settling conductive silicone rubber according to any one of claims 1 to 9, characterized in that: The following steps are involved: (1) Preparation of base material: 80 parts by mass of vinyl silicone oil, 15 to 30 parts by mass of fumed silica, 2 to 15 parts by mass of hexamethyldisilazane, and 2 to 10 parts by mass of water are stirred in a vacuum kneader for 60 to 180 minutes, then heated to 120° C. to 200° C. and stirred for 90 to 200 minutes, and after cooling, 120 to 200 parts by mass of a modified composite conductive filler are added, and then the mixture is blended for 60 to 180 minutes at a vacuum degree of -0.08 to -0.1 MPa, and then diluted, cooled, and ground to obtain a base material; (2) Preparation of low-viscosity, high-performance, anti-settling conductive silicone rubber: 100 parts by mass of base material, 5-15 parts by mass of vinyl silicone resin, 3-10 parts by mass of dimethyl silicone oil and 1-5 parts by mass of hydrogenated silicone oil are added into a planetary mixer with a cooling and high-speed dispersing device, stirred for 10-20 minutes at a high-speed dispersing speed of 500-1000 r / min and a low-speed stirring speed of 40-80 r / min, 0.1-1 parts by mass of inhibitor are added, stirred for 15-20 minutes at a high-speed dispersing speed of 300-600 r / min, a low-speed stirring speed of 30-60 r / min and a vacuum degree of -0.08 to -0.1 MPa, 0.1-1 parts by mass of platinum catalyst are added, stirred for 5-15 minutes at a high-speed dispersing speed of 300-600 r / min, a low-speed stirring speed of 30-60 r / min and a vacuum degree of -0.08 to -0.1 MPa, the material is discharged and sealed for storage to obtain a low-viscosity, high-performance, anti-settling conductive silicone rubber.

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