CN114539533A - Multi-branched polysiloxane, preparation method thereof and heat-conducting silicone gel - Google Patents
Multi-branched polysiloxane, preparation method thereof and heat-conducting silicone gel Download PDFInfo
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- 229920001296 polysiloxane Polymers 0.000 title claims abstract description 161
- -1 polysiloxane Polymers 0.000 title claims abstract description 128
- 238000002360 preparation method Methods 0.000 title abstract description 16
- 229920002545 silicone oil Polymers 0.000 claims abstract description 130
- 239000000945 filler Substances 0.000 claims abstract description 17
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 76
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 52
- 239000003054 catalyst Substances 0.000 claims description 46
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 claims description 43
- 239000001257 hydrogen Substances 0.000 claims description 41
- 229910052739 hydrogen Inorganic materials 0.000 claims description 41
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims description 38
- 239000011787 zinc oxide Substances 0.000 claims description 38
- 229920002554 vinyl polymer Polymers 0.000 claims description 36
- 238000002156 mixing Methods 0.000 claims description 28
- 239000002904 solvent Substances 0.000 claims description 16
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 claims description 8
- 239000011231 conductive filler Substances 0.000 claims description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 7
- 238000006243 chemical reaction Methods 0.000 claims description 6
- VTYYLEPIZMXCLO-UHFFFAOYSA-L Calcium carbonate Chemical compound [Ca+2].[O-]C([O-])=O VTYYLEPIZMXCLO-UHFFFAOYSA-L 0.000 claims description 4
- 239000002253 acid Substances 0.000 claims description 4
- MVPPADPHJFYWMZ-UHFFFAOYSA-N chlorobenzene Chemical compound ClC1=CC=CC=C1 MVPPADPHJFYWMZ-UHFFFAOYSA-N 0.000 claims description 4
- 238000000034 method Methods 0.000 claims description 4
- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 claims description 4
- 239000002994 raw material Substances 0.000 claims description 4
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 claims description 4
- 239000006087 Silane Coupling Agent Substances 0.000 claims description 3
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims description 3
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 3
- 239000000377 silicon dioxide Substances 0.000 claims description 3
- 229910052582 BN Inorganic materials 0.000 claims description 2
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims description 2
- 150000001336 alkenes Chemical class 0.000 claims description 2
- 229910000019 calcium carbonate Inorganic materials 0.000 claims description 2
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 claims description 2
- 239000000395 magnesium oxide Substances 0.000 claims description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims description 2
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims description 2
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 claims description 2
- 230000035484 reaction time Effects 0.000 claims description 2
- 235000012239 silicon dioxide Nutrition 0.000 claims description 2
- 238000004381 surface treatment Methods 0.000 claims description 2
- 239000012756 surface treatment agent Substances 0.000 claims description 2
- 239000007789 gas Substances 0.000 claims 8
- 238000004519 manufacturing process Methods 0.000 claims 4
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 claims 1
- 230000035699 permeability Effects 0.000 abstract description 19
- 239000011248 coating agent Substances 0.000 abstract description 4
- 238000000576 coating method Methods 0.000 abstract description 4
- 239000000047 product Substances 0.000 description 55
- 230000000052 comparative effect Effects 0.000 description 41
- 239000003921 oil Substances 0.000 description 29
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 27
- 239000002245 particle Substances 0.000 description 20
- 239000000499 gel Substances 0.000 description 19
- 239000012467 final product Substances 0.000 description 18
- 238000000227 grinding Methods 0.000 description 18
- 238000009210 therapy by ultrasound Methods 0.000 description 18
- YFCGDEUVHLPRCZ-UHFFFAOYSA-N [dimethyl(trimethylsilyloxy)silyl]oxy-dimethyl-trimethylsilyloxysilane Chemical compound C[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)C YFCGDEUVHLPRCZ-UHFFFAOYSA-N 0.000 description 16
- 239000012905 visible particle Substances 0.000 description 14
- 239000004519 grease Substances 0.000 description 10
- 230000003311 flocculating effect Effects 0.000 description 9
- 238000010438 heat treatment Methods 0.000 description 9
- 239000000203 mixture Substances 0.000 description 9
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 8
- 229910052782 aluminium Inorganic materials 0.000 description 8
- 238000007664 blowing Methods 0.000 description 8
- 239000006227 byproduct Substances 0.000 description 8
- 238000001816 cooling Methods 0.000 description 8
- 239000000178 monomer Substances 0.000 description 8
- HMMGMWAXVFQUOA-UHFFFAOYSA-N octamethylcyclotetrasiloxane Chemical compound C[Si]1(C)O[Si](C)(C)O[Si](C)(C)O[Si](C)(C)O1 HMMGMWAXVFQUOA-UHFFFAOYSA-N 0.000 description 8
- 238000003756 stirring Methods 0.000 description 8
- MYXKPFMQWULLOH-UHFFFAOYSA-M tetramethylazanium;hydroxide;pentahydrate Chemical compound O.O.O.O.O.[OH-].C[N+](C)(C)C MYXKPFMQWULLOH-UHFFFAOYSA-M 0.000 description 8
- 125000003944 tolyl group Chemical group 0.000 description 8
- 238000000354 decomposition reaction Methods 0.000 description 7
- 230000000379 polymerizing effect Effects 0.000 description 7
- 238000006459 hydrosilylation reaction Methods 0.000 description 6
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 4
- 239000011737 fluorine Substances 0.000 description 4
- 229910052731 fluorine Inorganic materials 0.000 description 4
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 4
- 230000000740 bleeding effect Effects 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 229910018557 Si O Inorganic materials 0.000 description 2
- 229920013822 aminosilicone Polymers 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 238000002844 melting Methods 0.000 description 2
- 230000008018 melting Effects 0.000 description 2
- 230000005012 migration Effects 0.000 description 2
- 238000013508 migration Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000000741 silica gel Substances 0.000 description 2
- 229910002027 silica gel Inorganic materials 0.000 description 2
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Inorganic materials [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 2
- 239000007858 starting material Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 238000005979 thermal decomposition reaction Methods 0.000 description 2
- 238000007259 addition reaction Methods 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000009194 climbing Effects 0.000 description 1
- 229910052681 coesite Inorganic materials 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000013329 compounding Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010292 electrical insulation Methods 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 230000009477 glass transition Effects 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 229910003465 moissanite Inorganic materials 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000000425 proton nuclear magnetic resonance spectrum Methods 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 238000007363 ring formation reaction Methods 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 229920002379 silicone rubber Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000007480 spreading Effects 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
- C08G77/42—Block-or graft-polymers containing polysiloxane sequences
- C08G77/44—Block-or graft-polymers containing polysiloxane sequences containing only polysiloxane sequences
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/20—Oxides; Hydroxides
- C08K3/22—Oxides; Hydroxides of metals
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
- C08K3/20—Oxides; Hydroxides
- C08K3/22—Oxides; Hydroxides of metals
- C08K2003/2296—Oxides; Hydroxides of metals of zinc
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K2201/00—Specific properties of additives
- C08K2201/011—Nanostructured additives
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2203/00—Applications
- C08L2203/20—Applications use in electrical or conductive gadgets
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- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Silicon Polymers (AREA)
Abstract
The invention discloses a multi-branched polysiloxane, a preparation method thereof and a low-exudation heat-conducting silicone gel. The multi-branched polysiloxane has a structure shown in (I),
wherein m is 2 to 100 and n is 2 to 2000. The multi-branched polysiloxane is obtained by grafting silicone oil with single-end reactive groups on silicone oil with multi-end reactive groups. The heat-conducting silicone gel prepared from the polysiloxane with the multi-branched-chain structure and the heat-conducting filler has improved oil permeability and good coating property.
Description
Technical Field
The invention relates to the field of organic silicon materials, in particular to multi-branched polysiloxane, a preparation method thereof and low-exudation heat-conducting silicone gel.
Background
With the continuous development of electronic devices toward high performance, integration and miniaturization, the heat generated during the operation of the devices is increased dramatically, which seriously affects the long-term reliability of the devices, so that the thermal interface material is very important. The organic silicon elastomer can be widely applied to heat dissipation of electronic devices as a thermal interface material by virtue of excellent electrical insulation, high and low temperature resistance, flexibility, chemical inertness and the like.
The heat-conducting silicone grease is a mixture of low-molecular-weight silicone oil and heat-conducting filler, is a thermal interface material mainly adopted at present, but can cause the leakage of low-molecular-weight silicone oil in the use process, so that the phenomenon of oil climbing is caused, and the safety, reliability and service life of a device are seriously threatened.
The main existing method for improving the oil permeability of the heat-conducting silicone grease comprises the following steps: (1) improving the molecular weight of the basic silicone oil: generally, the larger the molecular weight of the base silicone oil, the lower the oil bleeding amount, but the larger the molecular weight of the base silicone oil, the more difficult the bubble removal during the preparation process and the coating at the time of use. (2) Compounding and modifying the heat-conducting filler: by carrying out surface modification on the heat-conducting filler/the basic silicone oil, the compatibility between the heat-conducting filler/the basic silicone oil and the basic silicone oil can be enhanced, so that the oil permeability of the silicone grease can be effectively improved; through the compound use of the heat-conducting filler, the filling amount of the heat-conducting filler is favorably improved, so that the heat-conducting property is improved, and the filler forms a stable structure in a system, so that the oil seepage amount is reduced. (3) And hydrogen bonding force is constructed in a composite material system to improve the oil permeability. At present, the research on the oil leakage problem of the heat-conducting silicone grease is not deep enough, the oil leakage problem cannot be solved well, and further research is needed.
Disclosure of Invention
In order to solve the problems existing in the prior art, the invention improves the oil permeability by designing the topological network structure of the silica gel: the single-component multi-branched polysiloxane for constructing the physical entanglement network is provided, polysiloxane macromolecular chains with branched structures are formed by silicone oil with multi-terminal reactive groups and silicone oil with single-terminal reactive groups through hydrosilylation, and a three-dimensional physical entanglement network is formed by utilizing the characteristic that the macromolecular chains are entangled with each other to inhibit the migration of low-molecular-weight silicone oil in a system, and meanwhile, the single-component multi-branched polysiloxane has good coating property.
An object of the present invention is to provide a multi-branched polysiloxane having a structure represented by the following formula (I):
wherein m is 2-100, n is 2-2000; preferably, m is 4-50; n is 4 to 1000.
The viscosity of the multi-branched polysiloxane is 100-100000 mPas, preferably 100-40000 mPas, and more preferably 200-5000 mPas.
The number average molecular weight Mn of the multi-branched polysiloxane is 20000-600000 g/mol, preferably 40000-300000 g/mol.
The multi-branched polysiloxane is obtained by grafting silicone oil with a single-end reactive group on multi-end reactive group silicone oil, wherein the multi-end reactive group silicone oil is side chain hydrogen-containing silicone oil or side chain vinyl-containing silicone oil, and the single-end reactive group silicone oil is single-end vinyl silicone oil or single-end hydrogen-containing silicone oil.
The multi-terminal reactive group silicone oil has a plurality of lateral reactive groups, and the terminal group of the multi-terminal reactive group silicone oil is not particularly limited, and may or may not be a reactive group.
The second purpose of the invention is to provide a preparation method of the multi-branched polysiloxane, which comprises the steps of adding silicone oil with multi-terminal reactive groups, silicone oil with single-terminal reactive groups and a catalyst into a solvent, and reacting in an inert atmosphere.
The multi-branched polysiloxane is obtained by grafting silicone oil with a single-end reactive group on silicone oil with a multi-end reactive group.
The multi-terminal reactive group silicone oil is side chain hydrogen-containing silicone oil or side chain vinyl silicone oil, the reactive group of the side chain hydrogen-containing silicone oil is a hydrosilyl group, and the reactive group of the side chain vinyl silicone oil is a vinyl group.
The single-end reactive group silicone oil is single-end vinyl silicone oil or single-end hydrogen-containing silicone oil, the reactive group of the single-end vinyl silicone oil is vinyl, and the reactive group of the single-end hydrogen-containing silicone oil is hydrosilyl.
Wherein the silicone oil with the multi-terminal reactive group and the silicone oil with the single-terminal reactive group form multi-branched polysiloxane through hydrosilylation reaction.
Specifically, the multi-branched polysiloxane can be obtained by grafting single-end vinyl silicone oil on side chain hydrogen-containing silicone oil, or by grafting single-end hydrogen-containing silicone oil on side chain vinyl silicone oil.
The molar ratio of the reactive group in the silicone oil having a single terminal reactive group to the reactive group in the silicone oil having a multi terminal reactive group is 1 to 10, preferably 1 to 5, more preferably 1 to 2, further preferably 1 to 1.5, and may be, for example, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 3, 4, 5, 6, 7, 8, 9, 10, or the like.
The viscosity of the single-end reactive group silicone oil is 50-10000 cst, preferably 80-5000 cst, and more preferably 80-800 cst.
The viscosity of the multi-end reactive group silicone oil is 10-10000 cst, preferably 10-1000 cst, and more preferably 20-200 cst; the content of the reactive group is 0.1 to 90 wt%, preferably 0.3 to 50 wt%, and more preferably 0.3 to 40 wt%.
The solvent is at least one of toluene, chlorobenzene, tetrahydrofuran and n-hexane, and toluene is preferred.
The amount of the solvent is 5-20 ml/g of silicone oil, preferably 10-15 ml/g of silicone oil, based on the total mass of the silicone oil with the multi-terminal reactive group and the silicone oil with the single-terminal reactive group.
The catalyst is preferably a chloroplatinic acid complex including, but not limited to, at least one of an olefin complex, tetrahydrofuran complex, vinyl siloxane complex, and the like of chloroplatinic acid.
The amount of the catalyst is 20-200 ppm, preferably 60-100 ppm, based on the total mass of the silicone oil with the multi-terminal reactive group and the silicone oil with the single-terminal reactive group.
The reaction temperature is 60-100 ℃, and the reaction time is 4-8 h.
The multi-terminal reactive group silicone oil and the single-terminal reactive group silicone oil form a polysiloxane polymer chain with a branched structure through hydrosilylation, and the reaction equation is as follows:
the reaction equation one:
the reaction equation two:
it is a further object of the present invention to provide a thermally conductive silicone gel comprising the multi-branched polysiloxane and a thermally conductive filler.
The heat-conducting filler is preferably at least one of alumina, zinc oxide, magnesium oxide, boron nitride, aluminum nitride, silicon carbide, calcium carbonate and silicon dioxide.
The thermally conductive filler is preferably subjected to a surface treatment, wherein the surface treatment agent may be a silane coupling agent generally used in the art.
The surface treating agent is mainly a silane coupling agent, and includes but is not limited to at least one of KH151, KH171, KH550, KH560, KH570, KH602, KH792, KH331 and the like.
The heat-conducting filler can be compounded by various different fillers, and can also be compounded by single heat-conducting filler with different particle sizes.
Furthermore, fluorine-containing silicone oil, hydroxyl silicone oil, fluorine-containing hydroxyl silicone oil, amino silicone oil and the like can be added into the heat-conducting silicone gel, so that a hydrogen bond network is constructed in a system, and the exudation is further reduced. The amount of the fluorine-containing silicone oil and the like to be used is not particularly limited, and those generally used in the art can be used.
The following list several types of hydroxyl silicone oil, fluorine-containing hydroxyl silicone oil and amino silicone oil which can be used:
in the thermally conductive silicone gel of the present invention, the amounts of the multi-branched polysiloxane and the thermally conductive filler are not particularly limited, and those generally used in the art can be used.
According to a preferred embodiment of the present invention, the thermally conductive silicone gel includes 100 parts by mass of a multi-branched polysiloxane and 100 to 3000 parts by mass of a thermally conductive filler, and more preferably, includes 100 parts by mass of a multi-branched polysiloxane and 200 to 1000 parts by mass of a thermally conductive filler.
The fourth purpose of the invention is to provide a preparation method of the heat-conducting silicone gel, which comprises the step of blending raw materials including the multi-branched polysiloxane and the heat-conducting filler.
Specifically, the preparation method of the heat-conducting silicone gel comprises the steps of blending, carrying out ultrasonic treatment and grinding on multi-branched polysiloxane and a heat-conducting filler until the silicone grease is fine and uniform and has no visible particles, and finally standing in a vacuum oven at 80-120 ℃ for 1-6 hours to obtain a final product.
Preferably, the amount of the heat conductive filler is 100 to 3000 parts by mass, more preferably 200 to 1000 parts by mass, based on 100 parts by mass of the branched polysiloxane.
The invention improves the oil permeability by designing the topological network structure of the silica gel: the method is characterized in that single-component silicone gel of a physical entanglement network is constructed, silicone oil with multiple reactive groups at different types and silicone oil with single reactive groups at different types are used for forming polysiloxane macromolecular chains with long branched chain structures through hydrosilylation, and a three-dimensional physical entanglement network is formed by utilizing the characteristic that the macromolecular chains are entangled with each other to inhibit the migration of low molecular weight silicone oil in a system, and meanwhile, the silicone gel has good coating property.
The invention has the beneficial effects that:
(1) the invention designs and synthesizes polysiloxane with a multi-branched structure, and effectively improves the oil permeability of silicone grease through the characteristic that polymer chains are mutually entangled;
(2) the number average molecular weight of the synthesized multi-branched polysiloxane is designed to be more than 4 times that of the linear polysiloxane with the same viscosity, because the multi-branched polysiloxane has larger coil volume compared with the linear polysiloxane, the apparent viscosity of the multi-branched polysiloxane is lower than that of the linear polysiloxane under the condition of the same molecular weight, and the mobility of the multi-branched polysiloxane is lower than that of the linear polysiloxane with the same viscosity under the condition of the same viscosity;
(3) the heat-conducting silicone grease prepared from the multi-branched polysiloxane with higher molecular weight has better spreadability in practical application and proves that the heat-conducting silicone grease has better coatability.
Drawings
FIG. 1 is a schematic diagram of the construction of a multi-branched polysiloxane physical entanglement gel network prepared by side chain multi-hydrogen-containing silicone oil and single-terminal vinyl silicone oil.
FIG. 2 is a graph showing the results of the multi-branched polysiloxane of example 1 and the linear polysiloxane of comparative example 11H-NMR spectrum.
As shown in FIG. 2, the nuclear magnetic spectrum of the multi-branched polysiloxane showed a new peak at about 0.5ppm, which represents CH, as compared with that of the linear polysiloxane2-CH2H (a) in (A) shows that a beta-addition reaction is carried out between a single terminal vinyl silicone oil (MCR-V21) and a terminal/side hydrogen-containing silicone oil (RH-LHC-3).
FIG. 3 is a beta-hydrosilylation reaction equation for a single-terminal vinyl silicone oil and a multiple hydrogen-containing silicone oil.
FIG. 4 shows DSC temperature rise curves of various silicone oils.
In order to investigate the influence of the branched structure on the thermal properties of the silicone chains, the thermal properties of the single-terminal vinyl silicone oil (MCR-V21) and the terminal/side hydrogen-containing silicone oil (RH-LHC-3) as the starting materials in example 1 and the multi-branched polysiloxane as the product thereof, and the linear polysiloxane of comparative example 1 having the same viscosity, were characterized by DSC.
FIG. 5 is a thermogravimetric plot of various silicone oils.
In order to investigate the influence of the multi-branched structure on the thermal decomposition characteristics of the silicone chain, TGA tests were carried out on the single-terminal vinyl silicone oil (MCR-V21) and terminal/side hydrogen-containing silicone oil (RH-LHC-3) as the starting materials in example 1, and on the multi-branched polysiloxane as the product in comparative example 1, and on the linear polysiloxane of the same viscosity.
As can be seen from FIG. 5, the thermal decomposition temperature (Td) of the multi-branched polysiloxane exceeded 400 ℃, indicating that it has good thermal stability, meeting the practical application requirements. The residual weights of the raw materials of the single-end vinyl silicone oil (MCR-V21) and the end/side hydrogen-containing silicone oil (RH-LHC-3) are respectively 3.41 percent and 0 percent, and the residual weight of the linear polysiloxane with the same viscosity is 0.25 percent, which indicates that the thermal degradation mechanism only relates to the fracture recombination of Si-O bonds; the residual weight of the multi-branched polysiloxane was 65.08%, and this was analyzed because the branched steric hindrance of the product was large, and the hydrosilylation reaction produced a rigid group which hindered Si-O ring formation, thereby producing SiC and SiO2And the like.
Fig. 6 is a drawing showing spreading of silicone grease in example 1 and comparative example 1.
FIG. 7 shows the product obtained in comparative example 9.
The specific implementation mode is as follows:
the following detailed description of the invention, given in connection with the specific embodiments thereof, is intended to provide further explanation of the invention as claimed. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.
The raw materials used in the examples and comparative examples are disclosed in the prior art if not particularly limited, and may be, for example, directly purchased or prepared according to the preparation methods disclosed in the prior art.
The oil permeability test method comprises the following steps:
the same mass of product was coated on filter paper and placed in a 100 ℃ vacuum loopStanding for 120h in the environment, observing the oil permeability, and expressing the oil permeability by the oil permeability. The oil permeability is defined as the ratio of the diameter of the oil stain exuded in the sample to the initial diameter of the test sample, i.e. the oil permeability r ═ Dm/D0In which D is0Is the initial diameter of the sample; dmThe diameter of the oil stain contained after oil bleeding of the sample.
According to a preferred embodiment of the present invention, the preparation method may comprise:
(1) dissolving single-end reactive group silicone oil and a catalyst in a solvent, uniformly mixing, adding multi-end reactive group silicone oil, heating to 60-100 ℃, and reacting at N2Reacting for 4-8 h in the atmosphere, and flocculating out with methanol to obtain the multi-branched polysiloxane;
(2) and (2) blending the multi-branched polysiloxane prepared in the step (1) with a heat-conducting filler, performing ultrasonic treatment, grinding until the silicone grease is fine and uniform and has no visible particles, and finally standing in a vacuum oven at 120 ℃ for 1h to obtain a final product.
Example 1:
the low-seepage heat-conducting silicone gel comprises the following components in parts by weight:
100 parts by mass of single-ended vinyl silicone oil (MCR-V21) with the viscosity of 80-120 cst; 3 parts by mass of hydrogen-containing silicone oil (RH-LHC-3) with the viscosity of 35cst and the hydrogen content of 0.80 +/-0.02 wt%; wherein the group molar ratio of the vinyl group to the hydrosilyl group is 1: 1; the solution concentration is 10ml/g silicone oil, and the solvent is toluene; karstedt's catalyst was used at 60 ppm; zinc oxide with a particle size of 30 + -5 nm.
S1, mixing the single-end vinyl silicone oil, hydrogen-containing silicone oil, catalyst and toluene at 60 ℃ and N2Reacting for 6 hours in the atmosphere to obtain multi-branched polysiloxane, and flocculating out with methanol;
s2, blending 100 parts by mass of multi-branched polysiloxane prepared in the S1 and 100 parts by mass of zinc oxide, performing ultrasonic treatment, grinding to be fine and uniform without visible particles, and finally standing in a vacuum oven at 120 ℃ for 1h to obtain a final product.
Comparative example 1:
s1, preparing a linear polysiloxane having the same viscosity as the multi-branched polysiloxane of example 1;
100g of octamethylcyclotetrasiloxane (D)4) 0.85g of Decamethyltetrasiloxane (DMTS) is stirred at a constant speed for dewatering for 2 hours at the temperature of 40 ℃ and the pressure of 0.005 MPa; adding 0.02 wt% of catalyst tetramethylammonium hydroxide pentahydrate (TMAEOH 5H)2O); at 80 ℃ N2Stirring at constant speed for polymerizing for 8h under the conditions of atmosphere and normal pressure; heating to 150 deg.C to destroy catalyst, and reacting in N2Under blowing, vacuumizing to remove unreacted monomers, byproducts and catalyst decomposition products; finally cooling and taking out to obtain the colorless and transparent linear polysiloxane.
S2, blending 100 parts by mass of linear polysiloxane prepared by S2 and 100 parts by mass of zinc oxide with the particle size of 30 +/-5 nm, carrying out ultrasonic treatment, grinding to be fine and uniform without visible particles, and finally standing in a vacuum oven at 120 ℃ for 1h to obtain a final product.
The products of example 1 and comparative example 1 were coated on filter paper and left to stand in a vacuum environment at 100 ℃ for 120 hours, and the oil permeability of the product of comparative example 1 was 1.43 times that of the product of example 1, but the spreadability of the product of example 1 on an aluminum plate was 3.3 times that of the product of comparative example 1.
The molecular weight and viscosity of the polysiloxanes are characterized, taking example 1 and comparative example 1 as examples:
as can be seen from Table 1, the number average molecular weight of the multi-branched polysiloxane was 4.3 times that of the linear polysiloxane at the same viscosity.
TABLE 1
And the glass transition temperature (Tg), crystallization temperature (Tm), melting temperature (Tf), melting enthalpy of each type of silicone oil in example 1 and comparative example 1 are summarized in table 2.
Generally, as the molecular weight increases, the Tg, Tm, and Tf of the polysiloxane increase, and the molecular weight of the multi-branched polysiloxane in the present invention is more than 4 times that of the homoviscosity linear polysiloxane, but it can be seen from Table 2 that Tm and Tf of the multi-branched polysiloxane are both lower than that of the homoviscosity linear polysiloxane, which is analyzed because the branched structure of the multi-branched polysiloxane reduces the structural regularity thereof, which is also laterally confirmed to form a product having a branched structure.
Table 2: thermal property data of silicone oils
Example 2:
the low-seepage heat-conducting silicone gel comprises the following components in parts by weight:
100 parts by mass of single-ended vinyl silicone oil with the viscosity of 80-120 cst; 3 parts by mass of hydrogen-containing silicone oil with the viscosity of 35cst and the hydrogen content of 0.80 +/-0.02 wt%; wherein the group molar ratio of the vinyl group to the hydrosilyl group is 1: 1; the concentration of the solution is 10ml/g, and the solvent is toluene; karstedt's catalyst was used at 60 ppm; zinc oxide with a particle size of 30 +/-5 nm.
S1, mixing the single-end vinyl silicone oil, hydrogen-containing silicone oil, catalyst and toluene at 60 ℃ and N2Reacting for 6 hours in the atmosphere to obtain multi-branched polysiloxane, and flocculating out with methanol; the number average molecular weight of the multi-branched polysiloxane was 144226 g/mol.
S2, blending 100 parts by mass of multi-branched polysiloxane prepared by S1 and 200 parts by mass of zinc oxide with the particle size of 30 +/-5 nm, carrying out ultrasonic treatment, grinding to be fine and uniform without visible particles, and finally standing in a vacuum oven at 120 ℃ for 1h to obtain a final product.
Comparative example 2:
s1 preparation of a linear polysiloxane having the same viscosity as the multi-branched polysiloxane of example 2;
100g of octamethylcyclotetrasiloxane (D)4) 0.85g of Decamethyltetrasiloxane (DMTS) is stirred at a constant speed for dewatering for 2 hours at the temperature of 40 ℃ and the pressure of 0.005 MPa; adding 0.02 wt% of catalyst tetramethylammonium hydroxide pentahydrate (TMAEOH 5H)2O); at 80 ℃ N2Stirring at constant speed for polymerization for 8h under the conditions of atmosphere and normal pressure; heating to 150 deg.C to destroy catalyst, and reacting in N2Blowing, vacuumizing to remove unreacted monomer, by-product and catalystDecomposition products of the agent; finally cooling and taking out to obtain the colorless and transparent linear polysiloxane.
S2, blending 100 parts by mass of linear polysiloxane prepared by S2 and 200 parts by mass of zinc oxide with the particle size of 30 +/-5 nm, carrying out ultrasonic treatment, grinding to be fine and uniform without visible particles, and finally standing in a vacuum oven at 120 ℃ for 1h to obtain a final product.
The products of example 2 and comparative example 2 were coated on filter paper and left to stand in a vacuum environment at 100 ℃ for 120 hours, and the oil permeability of the product of comparative example 2 was 2.3 times that of the product of example 2, but the spreadability of the product of example 2 on an aluminum plate was 1.2 times that of the product of comparative example 2.
Example 3:
the low-seepage heat-conducting silicone gel comprises the following components in parts by weight:
100 parts by mass of single-ended vinyl silicone oil with the viscosity of 80-120 cst; 3.7 parts by mass of hydrogen-containing silicone oil with the viscosity of 40cst and the hydrogen content of 0.80 +/-0.02 wt%; wherein the group molar ratio of the vinyl group to the hydrosilyl group is 1: 1.2; the concentration of the solution is 10ml/g, and the solvent is toluene; karstedt's catalyst was used at 60 ppm; zinc oxide with a particle size of 30 + -5 nm.
S1, mixing the single-end vinyl silicone oil, hydrogen-containing silicone oil, catalyst and toluene at 60 ℃ and N2Reacting for 6 hours in the atmosphere to obtain multi-branched polysiloxane, and flocculating out with methanol; the number average molecular weight of the multi-branched polysiloxane was 91687 g/mol.
S2, blending 100 parts by mass of multi-branched polysiloxane prepared by S1 and 300 parts by mass of zinc oxide with the particle size of 30 +/-5 nm, carrying out ultrasonic treatment, grinding to be fine and uniform without visible particles, and finally standing in a vacuum oven at 120 ℃ for 1h to obtain a final product.
Comparative example 3:
s1, preparing a linear polysiloxane having the same viscosity as the multi-branched polysiloxane of example 3;
100g of octamethylcyclotetrasiloxane (D)4) 0.90g of Decamethyltetrasiloxane (DMTS) is stirred at a constant speed for dewatering for 2 hours at the temperature of 40 ℃ and the pressure of 0.005 MPa; adding 0.02 wt% of catalyst tetramethylammonium hydroxide pentahydrate (TMAEOH 5H)2O); at 80 ℃ N2Stirring at constant speed for polymerizing for 8h under the conditions of atmosphere and normal pressure; heating to 150 deg.C to destroy catalyst, and reacting in N2Under blowing, vacuumizing to remove unreacted monomers, byproducts and catalyst decomposition products; finally cooling and taking out to obtain the colorless and transparent linear polysiloxane.
S2, blending 100 parts by mass of linear polysiloxane prepared by S2 and 300 parts by mass of zinc oxide with the particle size of 30 +/-5 nm, carrying out ultrasonic treatment, grinding to be fine and uniform without visible particles, and finally standing in a vacuum oven at 120 ℃ for 1h to obtain a final product.
The products of example 3 and comparative example 3 were coated on filter paper and left to stand in a vacuum environment at 100 ℃ for 120 hours, and the oil permeability of the product of comparative example 3 was 2.8 times that of the product of example 3, but the spreadability of the product of example 3 on an aluminum plate was 1.4 times that of the product of comparative example 3.
Example 4:
a low-seepage heat-conducting silicone gel comprises the following components in parts by weight:
100 parts of single-ended vinyl silicone oil with the viscosity of 80-120 cst; 3 parts of hydrogen-containing silicone oil with the viscosity of 15cst and the hydrogen content of 0.60 +/-0.02 wt%; wherein the group molar ratio of the vinyl group to the hydrosilyl group is 1: 1; the concentration of the solution is 10ml/g, and the solvent is toluene; karstedt's catalyst was used at 70 ppm; 250 parts of zinc oxide by mass, and the particle size is 30 +/-5 nm.
S1, mixing the single-end vinyl silicone oil, hydrogen-containing silicone oil, catalyst and toluene at 60 ℃ and N2Reacting for 6 hours in the atmosphere to obtain multi-branched polysiloxane, and flocculating out with methanol; the number average molecular weight of the multi-branched polysiloxane was 83910 g/mol.
S2, blending 100 parts by mass of multi-branched polysiloxane prepared by S1 and 250 parts by mass of zinc oxide with the particle size of 30 +/-5 nm, carrying out ultrasonic treatment, grinding to be fine and uniform without visible particles, and finally standing in a vacuum oven at 120 ℃ for 1h to obtain a final product.
Comparative example 4:
s1 preparation of a linear polysiloxane having the same viscosity as the multi-branched polysiloxane of example 4:
100g of octamethylcyclotetrasiloxane (D)4) 1.05g of Decamethyltetrasiloxane (DMTS) is stirred at a constant speed for dewatering for 2 hours at the temperature of 40 ℃ and the pressure of 0.005 MPa; adding 0.02 wt% of catalyst tetramethylammonium hydroxide pentahydrate (TMAEOH 5H)2O); at 80 ℃ N2Stirring at constant speed for polymerizing for 8h under the conditions of atmosphere and normal pressure; heating to 150 deg.C to destroy catalyst, and reacting in N2Under blowing, vacuumizing to remove unreacted monomers, byproducts and catalyst decomposition products; finally cooling and taking out to obtain the colorless and transparent linear polysiloxane.
S2, blending 100 parts by mass of linear polysiloxane prepared by S1 and 250 parts by mass of zinc oxide with the particle size of 30 +/-5 nm, carrying out ultrasonic treatment, grinding to be fine and uniform without visible particles, and finally standing in a vacuum oven at 120 ℃ for 1h to obtain the final product.
The products of example 4 and comparative example 4 were coated on filter paper and left to stand in a vacuum environment at 100 ℃ for 120 hours, and the oil permeability of the product of comparative example 4 was 1.07 times that of the product of example 4, but the spreadability of the product of example 4 on an aluminum plate was 1.25 times that of the product of comparative example 4.
Example 5:
the low-seepage heat-conducting silicone gel comprises the following components in parts by weight:
100 parts of single-ended vinyl silicone oil with the viscosity of 80-120 cst; 4.7 parts of hydrogen-containing silicone oil with the viscosity of 15cst and the hydrogen content of 0.60 +/-0.02 wt%; wherein the group molar ratio of the vinyl group to the hydrosilyl group is 1: 1.2; the concentration of the solution is 10ml/g, and the solvent is toluene; karstedt's catalyst was used at 60 ppm; zinc oxide with the grain diameter of 30 plus or minus 5nm and zinc oxide with the grain diameter of 200 plus or minus 10 nm.
S1, mixing the single-end vinyl silicone oil, hydrogen-containing silicone oil, catalyst and toluene at 60 ℃ and N2Reacting for 6 hours in the atmosphere to obtain multi-branched polysiloxane, and flocculating out with methanol; the number average molecular weight of the multi-branched polysiloxane was 56718 g/mol.
S2, blending 100 parts by mass of the multi-branched polysiloxane prepared by the S1, 200 parts by mass of zinc oxide with the grain diameter of 30 +/-5 nm and 200 parts by mass of zinc oxide with the grain diameter of 200 +/-10 nm, carrying out ultrasonic treatment, grinding until the mixture is fine and uniform without visible grains, and finally standing in a vacuum oven at 120 ℃ for 1 hour to obtain a final product.
Comparative example 5:
s1 preparation of a linear polysiloxane having the same viscosity as the multi-branched polysiloxane of example 5:
100g of octamethylcyclotetrasiloxane (D)4) 1.2g of Decamethyltetrasiloxane (DMTS) is stirred at a constant speed for dewatering for 2 hours at the temperature of 40 ℃ and the pressure of 0.005 MPa; adding 0.02 wt% of catalyst tetramethylammonium hydroxide pentahydrate (TMAEOH 5H)2O); at 80 ℃ N2Stirring at constant speed for polymerizing for 8h under the conditions of atmosphere and normal pressure; heating to 150 deg.C to destroy catalyst, and reacting in N2Under blowing, vacuumizing to remove unreacted monomers, byproducts and catalyst decomposition products; finally cooling and taking out to obtain the colorless and transparent linear polysiloxane.
S2, blending 100 parts by mass of linear polysiloxane prepared by S1, 200 parts by mass of zinc oxide with the particle size of 30 +/-5 nm and 200 parts by mass of zinc oxide with the particle size of 200 +/-10 nm, carrying out ultrasonic treatment, grinding until the mixture is fine and uniform without visible particles, and finally standing in a vacuum oven at 120 ℃ for 1 hour to obtain a final product.
The products of example 5 and comparative example 5 were coated on filter paper and left standing in a vacuum environment at 100 ℃ for 120 hours, and the oil-bleeding rate of the product of comparative example 5 was 1.8 times that of the product of example 5, but the spreadability of the product of example 5 on an aluminum plate was 1.5 times that of the product of comparative example 5.
Example 6:
the low-seepage heat-conducting silicone gel comprises the following components in parts by weight:
100 parts of single-ended vinyl silicone oil with the viscosity of 400-700 cst; 3 parts of hydrogen-containing silicone oil with the viscosity of 40cst and the hydrogen content of 0.20 +/-0.02 wt%; wherein the group molar ratio of the vinyl group to the hydrosilyl group is 1: 1.2; the concentration of the solution is 10ml/g, and the solvent is toluene; karstedt's catalyst was used at 70 ppm; zinc oxide with the grain diameter of 30 plus or minus 5nm and zinc oxide with the grain diameter of 200 plus or minus 10 nm.
S1, mixing the single-end vinyl silicone oil, hydrogen-containing silicone oil, catalyst and toluene at 80 ℃ and N2Reacting for 6 hours in the atmosphere to obtain multi-branched polysiloxane, and flocculating out with methanol; highly branched polysiloxanesThe number average molecular weight of (2) is 516393 g/mol.
S2, blending 100 parts by mass of the multi-branched polysiloxane prepared by the S1, 100 parts by mass of zinc oxide with the grain diameter of 30 +/-5 nm and 100 parts by mass of zinc oxide with the grain diameter of 200 +/-10 nm, carrying out ultrasonic treatment, grinding until the mixture is fine and uniform without visible grains, and finally standing in a vacuum oven at 120 ℃ for 1 hour to obtain a final product.
Comparative example 6:
s1 preparation of a linear polysiloxane having the same viscosity as the multi-branched polysiloxane of example 6:
100g of octamethylcyclotetrasiloxane (D)4) 0.40g of Decamethyltetrasiloxane (DMTS) is stirred at a constant speed for dewatering for 2 hours at the temperature of 40 ℃ and the pressure of 0.005 MPa; adding 0.02 wt% of catalyst tetramethylammonium hydroxide pentahydrate (TMAEOH 5H)2O); at 80 ℃ N2Stirring at constant speed for polymerizing for 8h under the conditions of atmosphere and normal pressure; heating to 150 deg.C to destroy catalyst, and reacting in N2Under blowing, vacuumizing to remove unreacted monomers, byproducts and catalyst decomposition products; finally cooling and taking out to obtain the colorless and transparent linear polysiloxane.
S2, blending 100 parts by mass of the linear polysiloxane prepared by the S1, 100 parts by mass of zinc oxide with the grain diameter of 30 +/-5 nm and 100 parts by mass of zinc oxide with the grain diameter of 200 +/-10 nm, carrying out ultrasonic treatment, grinding until the mixture is fine and uniform without visible grains, and finally standing in a vacuum oven at 120 ℃ for 1 hour to obtain a final product.
The products of example 6 and comparative example 6 were coated on filter paper and left to stand in a vacuum environment at 100 ℃ for 120 hours, and the oil permeability of the product of comparative example 6 was 2.7 times that of the product of example 6, but the spreadability of the product of example 6 on an aluminum plate was 1.35 times that of the product of comparative example 6.
Example 7:
the low-seepage heat-conducting silicone gel comprises the following components in parts by weight:
100 parts of single-ended vinyl silicone oil with the viscosity of 80-120 cst; 8 parts of hydrogen-containing silicone oil with the viscosity of 100cst and the hydrogen content of 0.30 +/-0.02 wt%; wherein the group molar ratio of the vinyl group to the hydrosilyl group is 1: 1.5; the concentration of the solution is 15ml/g, and the solvent is toluene; karstedt's catalyst was used at 70 ppm; zinc oxide with the grain diameter of 30 plus or minus 5nm and zinc oxide with the grain diameter of 200 plus or minus 10 nm.
S1, mixing the single-end vinyl silicone oil, hydrogen-containing silicone oil, catalyst and toluene at 80 ℃ and N2Reacting for 6 hours in the atmosphere to obtain multi-branched polysiloxane, and flocculating out with methanol; the number-average molecular weight of the multi-branched polysiloxane was 90129 g/mol.
S2, blending 100 parts by mass of multi-branched polysiloxane prepared from S1, 250 parts by mass of zinc oxide with the particle size of 30 +/-5 nm and 250 parts by mass of zinc oxide with the particle size of 250 +/-10 nm, carrying out ultrasonic treatment, grinding until the mixture is fine and uniform without visible particles, and finally standing in a vacuum oven at 120 ℃ for 1 hour to obtain a final product.
Comparative example 7:
s1 preparation of a linear polysiloxane having the same viscosity as the multi-branched polysiloxane of example 7:
100g of octamethylcyclotetrasiloxane (D)4) 1.60g of Decamethyltetrasiloxane (DMTS) is stirred at a constant speed for dewatering for 2 hours at the temperature of 40 ℃ and the pressure of 0.005 MPa; adding 0.02 wt% of catalyst tetramethylammonium hydroxide pentahydrate (TMAEOH 5H)2O); at 80 ℃ N2Stirring at constant speed for polymerizing for 8h under the conditions of atmosphere and normal pressure; heating to 150 deg.C to destroy catalyst, and reacting in N2Under blowing, vacuumizing to remove unreacted monomers, byproducts and catalyst decomposition products; finally cooling and taking out to obtain the colorless and transparent linear polysiloxane.
S2, blending 100 parts by mass of linear polysiloxane prepared by S1, 250 parts by mass of zinc oxide with the particle size of 30 +/-5 nm and 250 parts by mass of zinc oxide with the particle size of 250 +/-10 nm, carrying out ultrasonic treatment, grinding until the mixture is fine and uniform without visible particles, and finally standing in a vacuum oven at 120 ℃ for 1 hour to obtain a final product.
The products of example 7 and comparative example 7 were coated on filter paper and left to stand in a vacuum environment at 100 ℃ for 120 hours, and the oil bleeding rate of the product of comparative example 7 was 3.1 times that of the product of example 7, but the spreadability of the product of example 7 on an aluminum plate was 1.55 times that of the product of comparative example 7.
Example 8:
the low-seepage heat-conducting silicone gel comprises the following components in parts by weight:
100 parts of single-end hydrogen-containing silicone oil with the viscosity of 150-250 cst; 3 parts of vinyl silicone oil with the viscosity of 30-40 cst and the vinyl content of 30 wt%; wherein the group molar ratio of the vinyl group to the hydrosilyl group is 1: 1; the concentration of the solution is 10ml/g, and the solvent is toluene; karstedt's catalyst was used at 80 ppm; zinc oxide with the grain diameter of 30 plus or minus 5nm and zinc oxide with the grain diameter of 200 plus or minus 10 nm.
S1, reacting the single-end hydrogen-containing silicone oil, the vinyl silicone oil, the catalyst and the toluene at 100 ℃ and N2Reacting for 6 hours in the atmosphere to obtain multi-branched polysiloxane, and flocculating out with methanol; the number average molecular weight of the multi-branched polysiloxane was 320224 g/mol.
S2, blending 100 parts by mass of the multi-branched polysiloxane prepared by the S1, 200 parts by mass of zinc oxide with the grain diameter of 30 +/-5 nm and 150 parts by mass of zinc oxide with the grain diameter of 200 +/-10 nm, carrying out ultrasonic treatment, grinding until the mixture is fine and uniform without visible grains, and finally standing in a vacuum oven at 120 ℃ for 1 hour to obtain a final product.
Comparative example 8:
s1 preparation of a linear polysiloxane having the same viscosity as the multi-branched polysiloxane of example 8:
100g of octamethylcyclotetrasiloxane (D)4) 1.58g of Decamethyltetrasiloxane (DMTS) is stirred at a constant speed for dewatering for 2 hours at the temperature of 40 ℃ and the pressure of 0.005 MPa; adding 0.02 wt% of catalyst tetramethylammonium hydroxide pentahydrate (TMAEOH 5H)2O); at 80 ℃ N2Stirring at constant speed for polymerizing for 8h under the conditions of atmosphere and normal pressure; heating to 150 deg.C to destroy catalyst, and reacting in N2Under blowing, vacuumizing to remove unreacted monomers, byproducts and catalyst decomposition products; finally cooling and taking out to obtain the colorless and transparent linear polysiloxane.
S2, blending 100 parts by mass of linear polysiloxane prepared by S1, 200 parts by mass of zinc oxide with the particle size of 30 +/-5 nm and 150 parts by mass of zinc oxide with the particle size of 200 +/-10 nm, carrying out ultrasonic treatment, grinding until the mixture is fine and uniform without visible particles, and finally standing in a vacuum oven at 120 ℃ for 1 hour to obtain a final product.
The products of example 8 and comparative example 8 were coated on filter paper and left to stand in a vacuum environment at 100 ℃ for 120 hours, and the oil permeability of the product of comparative example 8 was 1.5 times that of the product of example 8, but the spreadability of the product of example 8 on an aluminum plate was 1.35 times that of the product of comparative example 8.
Comparative example 9:
silicone oils were prepared as in example 1, except that the solvent toluene was not used. The obtained product is solid in shape, forms a cross-linked structure, is elastic, cannot be dissolved and only can be swelled.
The above-described embodiments are merely preferred examples of the present invention, which is not intended to limit the invention in any way, and any equivalent variations or modifications of the structure, features and principles described in the claims of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. A multi-branched polysiloxane having a structure represented by the following formula (I):
wherein m is 2 to 100 and n is 2 to 2000.
2. The multi-branched polysiloxane according to claim 1, characterized in that:
the viscosity of the multi-branched polysiloxane is 100-100000 mPas, preferably 100-40000 mPas;
the number average molecular weight of the multi-branched polysiloxane is 20000-600000 g/mol, preferably 40000-300000 g/mol.
3. The multi-branched polysiloxane according to claim 1, characterized in that:
the multi-branched polysiloxane is obtained by grafting silicone oil with a single-end reactive group on multi-end reactive group silicone oil, wherein the multi-end reactive group silicone oil is side chain hydrogen-containing silicone oil or side chain vinyl-containing silicone oil, and the single-end reactive group silicone oil is single-end vinyl silicone oil or single-end hydrogen-containing silicone oil.
4. A method for preparing the multi-branched polysiloxane according to any one of claims 1 to 3, which comprises adding silicone oil having multi-terminal reactive groups, silicone oil having single-terminal reactive groups and a catalyst to a solvent and carrying out the reaction in an inert atmosphere.
5. The method for producing a multi-branched polysiloxane according to claim 4, characterized in that:
the viscosity of the single-end reactive group silicone oil is 50-10000 cst, preferably 80-5000 cst; and/or the presence of a gas in the gas,
the viscosity of the multi-end reactive group silicone oil is 10-10000 cst, preferably 10-1000 cst; the content of the reactive group is 0.1-90 wt%, preferably 0.3-50 wt%; and/or the presence of a gas in the gas,
the catalyst is chloroplatinic acid complex, preferably at least one of olefin complex, tetrahydrofuran complex or vinyl siloxane complex of chloroplatinic acid; and/or the presence of a gas in the gas,
the solvent is at least one of toluene, chlorobenzene, tetrahydrofuran and n-hexane.
6. The method for producing a multi-branched polysiloxane according to claim 4, characterized in that:
the molar ratio of the reactive group in the single-end reactive group silicone oil to the reactive group in the multi-end reactive group silicone oil is 1-10, preferably 1-5.
The amount of the catalyst is 20 to 200ppm, preferably 60 to 100 ppm.
The amount of the solvent is 5 to 20ml/g, preferably 10 to 15 ml/g.
7. The method for producing a multi-branched polysiloxane according to claim 4, characterized in that:
the reaction temperature is 60-100 ℃, and the reaction time is 4-8 h.
8. A thermally conductive silicone gel comprising the multi-branched polysiloxane as claimed in any one of claims 1 to 3 and a thermally conductive filler.
9. A thermally conductive silicone gel according to claim 8, wherein:
the heat-conducting filler is at least one of aluminum oxide, zinc oxide, magnesium oxide, boron nitride, aluminum nitride, silicon carbide, calcium carbonate and silicon dioxide; and/or the presence of a gas in the gas,
the heat-conducting filler is subjected to surface treatment, wherein the surface treatment agent is preferably a silane coupling agent.
10. A method for producing the thermally conductive silicone gel according to claim 8 or 9, comprising blending raw materials comprising a multi-branched polysiloxane and a thermally conductive filler.
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| CN115322577B (en) * | 2022-09-14 | 2024-05-03 | 广东思泉新材料股份有限公司 | Heat-conducting gel and preparation method thereof |
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