CN116574476A - Organic silicon pouring sealant for PCB and processing technology thereof - Google Patents
Organic silicon pouring sealant for PCB and processing technology thereof Download PDFInfo
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- CN116574476A CN116574476A CN202310589182.XA CN202310589182A CN116574476A CN 116574476 A CN116574476 A CN 116574476A CN 202310589182 A CN202310589182 A CN 202310589182A CN 116574476 A CN116574476 A CN 116574476A
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- pouring sealant
- organic silicon
- pcb
- polydopamine
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- 239000000565 sealant Substances 0.000 title claims abstract description 121
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims abstract description 26
- 229910052710 silicon Inorganic materials 0.000 title claims abstract description 26
- 239000010703 silicon Substances 0.000 title claims abstract description 26
- 238000005516 engineering process Methods 0.000 title claims abstract description 17
- 238000012545 processing Methods 0.000 title claims abstract description 15
- 239000003094 microcapsule Substances 0.000 claims abstract description 57
- 229920001690 polydopamine Polymers 0.000 claims abstract description 57
- 239000000463 material Substances 0.000 claims abstract description 48
- UPMLOUAZCHDJJD-UHFFFAOYSA-N 4,4'-Diphenylmethane Diisocyanate Chemical compound C1=CC(N=C=O)=CC=C1CC1=CC=C(N=C=O)C=C1 UPMLOUAZCHDJJD-UHFFFAOYSA-N 0.000 claims abstract description 28
- 239000004114 Ammonium polyphosphate Substances 0.000 claims abstract description 18
- 235000019826 ammonium polyphosphate Nutrition 0.000 claims abstract description 18
- 229920001276 ammonium polyphosphate Polymers 0.000 claims abstract description 18
- 238000003756 stirring Methods 0.000 claims description 48
- 238000002156 mixing Methods 0.000 claims description 46
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 38
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 33
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 claims description 31
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical group ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 28
- 229920002396 Polyurea Polymers 0.000 claims description 22
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 19
- 229910052757 nitrogen Inorganic materials 0.000 claims description 19
- 238000005406 washing Methods 0.000 claims description 19
- -1 polydimethylsiloxane Polymers 0.000 claims description 15
- QYLFHLNFIHBCPR-UHFFFAOYSA-N 1-ethynylcyclohexan-1-ol Chemical compound C#CC1(O)CCCCC1 QYLFHLNFIHBCPR-UHFFFAOYSA-N 0.000 claims description 14
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 14
- 239000002253 acid Substances 0.000 claims description 14
- 239000002041 carbon nanotube Substances 0.000 claims description 14
- 229910021393 carbon nanotube Inorganic materials 0.000 claims description 14
- 239000004205 dimethyl polysiloxane Substances 0.000 claims description 14
- 238000004898 kneading Methods 0.000 claims description 14
- 229920000435 poly(dimethylsiloxane) Polymers 0.000 claims description 14
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 13
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 13
- 239000006229 carbon black Substances 0.000 claims description 13
- CTENFNNZBMHDDG-UHFFFAOYSA-N Dopamine hydrochloride Chemical compound Cl.NCCC1=CC=C(O)C(O)=C1 CTENFNNZBMHDDG-UHFFFAOYSA-N 0.000 claims description 12
- 229920001843 polymethylhydrosiloxane Polymers 0.000 claims description 12
- 229960001149 dopamine hydrochloride Drugs 0.000 claims description 11
- WGYFACNYUJGZQO-UHFFFAOYSA-N aminomethanetriol Chemical compound NC(O)(O)O WGYFACNYUJGZQO-UHFFFAOYSA-N 0.000 claims description 10
- 239000008367 deionised water Substances 0.000 claims description 10
- 229910021641 deionized water Inorganic materials 0.000 claims description 10
- 238000001035 drying Methods 0.000 claims description 9
- 238000000227 grinding Methods 0.000 claims description 9
- 238000009210 therapy by ultrasound Methods 0.000 claims description 9
- 238000004108 freeze drying Methods 0.000 claims description 8
- 230000001105 regulatory effect Effects 0.000 claims description 8
- 238000006243 chemical reaction Methods 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 6
- 229920001296 polysiloxane Polymers 0.000 claims description 4
- 239000003153 chemical reaction reagent Substances 0.000 claims description 2
- 230000035484 reaction time Effects 0.000 claims description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 abstract description 18
- 239000003063 flame retardant Substances 0.000 abstract description 18
- 229920002379 silicone rubber Polymers 0.000 abstract description 11
- 239000004945 silicone rubber Substances 0.000 abstract description 11
- 230000000694 effects Effects 0.000 abstract description 6
- 230000009286 beneficial effect Effects 0.000 abstract description 3
- 125000001951 carbamoylamino group Chemical group C(N)(=O)N* 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 11
- 238000001132 ultrasonic dispersion Methods 0.000 description 8
- 238000011049 filling Methods 0.000 description 5
- 238000007789 sealing Methods 0.000 description 5
- 239000000126 substance Substances 0.000 description 5
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000004382 potting Methods 0.000 description 3
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 2
- 229920001971 elastomer Polymers 0.000 description 2
- 239000004973 liquid crystal related substance Substances 0.000 description 2
- XSQUKJJJFZCRTK-UHFFFAOYSA-N urea group Chemical group NC(=O)N XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 2
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000006185 dispersion Substances 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- IQPQWNKOIGAROB-UHFFFAOYSA-N isocyanate group Chemical group [N-]=C=O IQPQWNKOIGAROB-UHFFFAOYSA-N 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 238000009864 tensile test Methods 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
- C09J175/02—Polyureas
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
- C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
- C09J11/02—Non-macromolecular additives
- C09J11/04—Non-macromolecular additives inorganic
-
- 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
- C08K3/32—Phosphorus-containing compounds
- C08K2003/321—Phosphates
- C08K2003/322—Ammonium phosphate
- C08K2003/323—Ammonium polyphosphate
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2201/00—Properties
- C08L2201/02—Flame or fire retardant/resistant
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2201/00—Properties
- C08L2201/08—Stabilised against heat, light or radiation or oxydation
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Sealing Material Composition (AREA)
Abstract
The invention relates to the technical field of electronic pouring sealant, in particular to an organic silicon pouring sealant for a PCB and a processing technology thereof. In order to improve the flame retardant property of the organic silicon pouring sealant, the invention wraps the ammonium polyphosphate by polydopamine to prepare polydopamine microcapsules; the organic silicon pouring sealant is treated by adopting diphenylmethane diisocyanate to obtain ureido-functionalized silicone rubber, and the introduction of ureido is beneficial to the polar action between organic silicon pouring sealant molecules, so that the acting force between the organic silicon pouring sealant molecules is enhanced, the free volume inside the material is reduced, and the mechanical property is improved. The poly-dopamine microcapsule is modified by the diphenylmethane diisocyanate, so that the compatibility of the poly-dopamine microcapsule and the ureido-functionalized silicone rubber is improved, and the poly-dopamine microcapsule can be more uniformly dispersed, and the flame retardant effect of the microcapsule is improved. In addition, the polydopamine has better thermal stability, so that the heat resistance of the organosilicon pouring sealant can be improved.
Description
Technical Field
The invention relates to the technical field of electronic pouring sealant, in particular to an organic silicon pouring sealant for a PCB and a processing technology thereof.
Background
The potting operation is an important procedure for the assembly of the PCB circuit board. The encapsulation plays a role in protecting the PCB against water, dust and chemical corrosion, and can also avoid adverse effects of factors such as environment, climate and the like on the PCB.
The organic silicon pouring sealant is used as a common pouring material, has excellent physicochemical properties and is not easy to age. The heat-resistant and weather-resistant performance is good, the heat-resistant and weather-resistant composite material can be used at the temperature of between 40 ℃ below zero and 200 ℃ and is suitable for protecting electronic elements in extremely severe environments. With the development of technology, electronic products have more programs to be processed, high running speed and more heat dissipation, so that higher requirements on heat conduction and flame retardance of each component of the electronic products are provided. The organic silicon pouring sealant is easy to burn and needs to be modified due to the property of the material. The traditional flame-retardant method of the organic silicon pouring sealant is to add environment-friendly flame retardant aluminum hydroxide and heat conducting material aluminum oxide in the preparation process, but due to the large addition amount, on one hand, the compatibility of inorganic materials and a resin matrix is poor, and the mechanical property of the pouring sealant is reduced; on the other hand, aluminum hydroxide is easy to decompose when heated, so that the heat resistance of the pouring sealant is poor. Therefore, a new method for flame-retardant modification of silicone potting adhesive needs to be tried.
Disclosure of Invention
The invention aims to provide an organic silicon pouring sealant for a PCB and a processing technology thereof, so as to solve the problems in the background technology.
In order to solve the technical problems, the invention provides the following technical scheme:
step 1: mixing trihydroxy aminomethane with deionized water, adding dilute hydrochloric acid to adjust the pH value, adding dopamine hydrochloride to stir for 15-30 min, adding ammonium polyphosphate, carrying out ultrasonic dispersion treatment for 3-6 h, heating in a water bath to 50-65 ℃, standing for 24-36 h, washing, drying and grinding to obtain polydopamine microcapsules;
step 2: dispersing the polydopamine microcapsule in dimethylformamide, carrying out ultrasonic treatment for 20-30 min, adding diphenylmethane diisocyanate in a nitrogen environment, carrying out heating reaction, washing, and freeze-drying to obtain a modified polydopamine microcapsule;
step 3: reacting a, omega-divinyl polydimethylsiloxane and diphenylmethane diisocyanate to obtain polyurea; kneading polyurea, modified polydopamine microcapsules, white carbon black and carbon nanotubes to obtain a pouring sealant base material;
step 4: mixing pouring sealant base material and isopropyl alcohol solution of chloroplatinic acid, and stirring for 30-60 min at a stirring speed of 5000-8000 rpm to obtain a pouring sealant A component; mixing pouring sealant base material, polymethyl hydrosiloxane and ethynyl cyclohexanol, and stirring for 30-60 min at a stirring speed of 5000-8000 rpm to obtain a pouring sealant B component;
step 5: taking a PCB, and mixing the component A of pouring sealant and the component B of pouring sealant according to the weight ratio of 1: (1-2.3) uniformly mixing, filling and sealing, and vulcanizing at 50-100 ℃ for 20-30 h.
Further, in the step 1, the components are mixed by weight, 1 to 1.5 parts of trihydroxy aminomethane, 400 to 500 parts of deionized water, 1.5 to 2.3 parts of dopamine hydrochloride and 10 to 15 parts of ammonium polyphosphate.
In the step 1, the concentration of the dilute hydrochloric acid is 0.5-1 mol/L.
In step 1, the pH value is adjusted to 8.0-8.5 by the dilute hydrochloric acid.
Further, in the step 2, the amounts of the components are, by weight, 10 to 20 parts of polydopamine microcapsules, 200 to 300 parts of dimethylformamide and 30 to 50 parts of diphenylmethane diisocyanate.
In the step 2, the reaction temperature is 80-90 ℃ and the reaction time is 8-12 h.
Further, in step 2, the washing reagent is dichloromethane.
In the step 3, the reaction condition is that the nitrogen is used for reacting for 8 to 9 hours at the temperature of 0 ℃; n (a, ω -divinyl polydimethylsiloxane): n (diphenylmethane diisocyanate) =1:1.
In the step 3, the usage amount of each component in the pouring sealant base material is 100-120 parts by weight of polyurea, 20-30 parts by weight of modified polydopamine microcapsule, 10-15 parts by weight of white carbon black and 10-15 parts by weight of carbon nano tube.
Further, in the step 3, the kneading temperature is 100 to 140℃and the kneading time is 3 to 5 hours.
Further, in the step 4, the amount of each component in the pouring sealant A is 100-120 parts by weight of pouring sealant base material and 1.0X10 -6 ～8.5×10 -6 Parts of chloroplatinic acid in isopropanol.
In the step 4, the pouring sealant B comprises 100-120 parts by weight of pouring sealant base material, 8-15 parts by weight of polymethyl hydrogen siloxane and 0.05-0.1 part by weight of ethynyl cyclohexanol.
Compared with the prior art, the invention has the following beneficial effects: according to the invention, the diphenyl methane diisocyanate is adopted to modify the organic silicon pouring sealant, and the introduction of the ureido enables the polarity effect generated between organic silicon pouring sealant molecules to increase the interaction force of the organic silicon pouring sealant molecules, so that the free volume inside the material is reduced, and the mechanical property is further improved. The microcapsule is prepared by wrapping the flame-retardant material ammonium polyphosphate by polydopamine, and then the polydopamine microcapsule is modified by using diphenylmethane diisocyanate, so that the dispersibility of the polydopamine microcapsule in the organosilicon pouring sealant is improved, and the flame-retardant effect of the microcapsule is improved; because the polydopamine has better thermal stability, the addition of the polydopamine can also improve the heat resistance of the organosilicon pouring sealant.
Detailed Description
The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The main materials and sources thereof in the following examples are as follows:
trihydroxyaminomethane (CAS number: 77-86-1), dilute hydrochloric acid (CAS number: 7647-01-1), dopamine hydrochloride (CAS number: 62-31-7), dimethylformamide (CAS number: 127-19-5), diphenylmethane diisocyanate (CAS number: 5101-68-8), and dichloromethane (CAS number: 75-09-2) are purchased from Guozhongxing chemical industry; carbon nanotubes are purchased from first-come nanomaterials; ethynyl cyclohexanol (CAS number 78-27-3) was purchased from Norna chemistry; an isopropyl alcohol solution of chloroplatinic acid was purchased for Yu Yurui chemistry; ammonium polyphosphate purchased from Lvsen chemical industry, cat number TY1324; a, purchasing Yu Mingyi silicon industry, product number MY273 by omega-divinyl polydimethylsiloxane; polymethylhydrosiloxane is purchased from Shandong chemical under the designation 202.
Example 1:
step 1: mixing 1g of trihydroxy aminomethane with 400g of deionized water, adding dilute hydrochloric acid with the concentration of 0.5mol/L, regulating the pH value to 8.0, adding 1.5g of dopamine hydrochloride, stirring for 15min, adding 10g of ammonium polyphosphate, performing ultrasonic dispersion treatment for 3h, heating to 50 ℃ in a water bath, standing for 24h, washing, drying and grinding to obtain polydopamine microcapsules;
step 2: dispersing 10g of polydopamine microcapsules in 200g of dimethylformamide, carrying out ultrasonic treatment for 20min, adding 30g of diphenylmethane diisocyanate in a nitrogen environment, heating to 80 ℃, reacting for 8h, washing with dichloromethane, and freeze-drying to obtain modified polydopamine microcapsules;
step 3: reacting 1mol of a, omega-divinyl polydimethylsiloxane with 1mol of diphenylmethane diisocyanate in a nitrogen environment at 0 ℃ for 8 hours to obtain polyurea; kneading 100kg of polyurea, 20kg of modified polydopamine microcapsule, 10kg of white carbon black and 10kg of carbon nano tube for 3 hours at 100 ℃ to obtain a pouring sealant base material;
step 4: 100kg of pouring sealant base material and 1.0X10 are added -6 Mixing kg of isopropanol solution of chloroplatinic acid, and stirring for 30min at a stirring speed of 5000rpm to obtain a pouring sealant A component; mixing 100kg of pouring sealant base material, 8kg of polymethylhydrosiloxane and 0.05kg of ethynyl cyclohexanol, and stirring at a stirring speed of 5000rpm for 30min to obtain a pouring sealant B component;
step 5: taking a PCB, and mixing the component A of pouring sealant and the component B of pouring sealant according to the weight ratio of 1:1, uniformly mixing, encapsulating, and vulcanizing at 50 ℃ for 20 hours.
Example 2:
step 1: mixing 1.1g of trihydroxy aminomethane with 420g of deionized water, adding dilute hydrochloric acid with the concentration of 0.55mol/L, regulating the pH value to 8.1, adding 1.6g of dopamine hydrochloride, stirring for 20min, adding 10.5g of ammonium polyphosphate, performing ultrasonic dispersion treatment for 3h, heating to 55 ℃ in a water bath, standing for 25h, washing, drying and grinding to obtain polydopamine microcapsules;
step 2: dispersing 11g of polydopamine microcapsules in 210g of dimethylformamide, carrying out ultrasonic treatment for 25min, adding 32g of diphenylmethane diisocyanate in a nitrogen environment, heating to 85 ℃, reacting for 10h, washing with dichloromethane, and freeze-drying to obtain modified polydopamine microcapsules;
step 3: reacting 1mol of a, omega-divinyl polydimethylsiloxane with 1mol of diphenylmethane diisocyanate in a nitrogen environment at 0 ℃ for 8.5 hours to obtain polyurea; kneading 110kg of polyurea, 22kg of modified polydopamine microcapsule, 11kg of white carbon black and 14kg of carbon nano tube for 3-5 hours at 100-140 ℃ to obtain a pouring sealant base material;
step 4: 100kg of pouring sealant base material and 1.5X10 are added -6 Mixing kg of isopropanol solution of chloroplatinic acid, and stirring for 45min at a stirring speed of 5600rpm to obtain a pouring sealant A component; 110kg of pouring sealant base material, 9kg of polymethylhydrosiloxane and 0.06kg of ethynyl cyclohexanol are mixed, and stirred for 45min at a stirring speed of 5600rpm, so that a pouring sealant B component is obtained;
step 5: taking a PCB, and mixing the component A of pouring sealant and the component B of pouring sealant according to the weight ratio of 1:1.1 mixing evenly, filling and sealing, and vulcanizing for 22 hours at 55 ℃.
Example 3:
step 1: mixing 1.25g of trihydroxy aminomethane with 450g of deionized water, adding dilute hydrochloric acid with the concentration of 0.6mol/L, regulating the pH value to 8.3, adding 1.8g of dopamine hydrochloride, stirring for 20min, adding 13g of ammonium polyphosphate, performing ultrasonic dispersion treatment for 3.5h, heating to 60 ℃ in a water bath, standing for 26h, washing, drying and grinding to obtain polydopamine microcapsules;
step 2: dispersing 15g of polydopamine microcapsules in 240g of dimethylformamide, carrying out ultrasonic treatment for 25min, adding 40g of diphenylmethane diisocyanate in a nitrogen environment, heating to 85 ℃, reacting for 11h, washing with dichloromethane, and freeze-drying to obtain modified polydopamine microcapsules;
step 3: reacting 1mol of a, omega-divinyl polydimethylsiloxane with 1mol of diphenylmethane diisocyanate in a nitrogen environment at 0 ℃ for 9 hours to obtain polyurea; kneading 105kg of polyurea, 26kg of modified polydopamine microcapsule, 13kg of white carbon black and 14kg of carbon nano tube for 4 hours at 120 ℃ to obtain a pouring sealant base material;
step 4: 115kg of pouring sealant base material and 2 multiplied by 10 -6 Mixing kg of isopropanol solution of chloroplatinic acid, and stirring for 40min at a stirring speed of 6000rpm to obtain a pouring sealant A component; mixing 115kg of pouring sealant base material, 7kg of polymethylhydrosiloxane and 0.08kg of ethynyl cyclohexanol, and stirring at a stirring speed of 6000rpm for 50min to obtain a pouring sealant B component;
step 5: taking a PCB, and mixing the component A of pouring sealant and the component B of pouring sealant according to the weight ratio of 1:1.65 are evenly mixed and encapsulated, and vulcanized for 25 hours at 70 ℃.
Example 4:
step 1: mixing 1.35g of trihydroxy aminomethane with 480g of deionized water, adding dilute hydrochloric acid with the concentration of 0.72mol/L, regulating the pH value to 8.4, adding 1.86g of dopamine hydrochloride, stirring for 20min, adding 13.8g of ammonium polyphosphate, performing ultrasonic dispersion treatment for 4.5h, heating to 60 ℃ in a water bath, standing for 30h, washing, drying and grinding to obtain polydopamine microcapsules;
step 2: dispersing 18g of polydopamine microcapsules in 250g of dimethylformamide, carrying out ultrasonic treatment for 25min, adding 40g of diphenylmethane diisocyanate in a nitrogen environment, heating to 75 ℃, reacting for 11h, washing with dichloromethane, and freeze-drying to obtain modified polydopamine microcapsules;
step 3: reacting 1mol of a, omega-divinyl polydimethylsiloxane with 1mol of diphenylmethane diisocyanate in a nitrogen environment at 0 ℃ for 8 hours to obtain polyurea; kneading 110kg of polyurea, 27kg of modified polydopamine microcapsule, 14kg of white carbon black and 14kg of carbon nano tube for 4 hours at 130 ℃ to obtain a pouring sealant base material;
step 4: 118kg of pouring sealant base material and 3.5X10 are added -6 Mixing kg of isopropanol solution of chloroplatinic acid, and stirring for 45min at a stirring speed of 6500rpm to obtain a pouring sealant A component; 118kg of pouring sealant base material, 13kg of polymethylhydrosiloxane and 0.06kg of ethynyl cyclohexanol are mixed and stirred for 60min at a stirring speed of 6500rpm to obtain pouring sealant B groupDividing;
step 5: taking a PCB, and mixing the component A of pouring sealant and the component B of pouring sealant according to the weight ratio of 1:1.8, uniformly mixing, filling and sealing, and vulcanizing at 80 ℃ for 25 hours.
Example 5:
step 1: mixing 1.4g of trihydroxy aminomethane with 450g of deionized water, adding dilute hydrochloric acid with the concentration of 0.76mol/L, regulating the pH value to 8.4, adding 1.9g of dopamine hydrochloride, stirring for 25min, adding 13g of ammonium polyphosphate, performing ultrasonic dispersion treatment for 5h, heating to 60 ℃ in a water bath, standing for 28h, washing, drying and grinding to obtain polydopamine microcapsules;
step 2: dispersing 17g of polydopamine microcapsules in 270g of dimethylformamide, carrying out ultrasonic treatment for 26min, adding 44g of diphenylmethane diisocyanate in a nitrogen environment, heating to 85 ℃, reacting for 11h, washing with dichloromethane, and freeze-drying to obtain modified polydopamine microcapsules;
step 3: reacting 1mol of a, omega-divinyl polydimethylsiloxane with 1mol of diphenylmethane diisocyanate in a nitrogen environment at 0 ℃ for 8.5 hours to obtain polyurea; kneading 105kg of polyurea, 27kg of modified polydopamine microcapsule, 13kg of white carbon black and 13kg of carbon nano tube for 4.5 hours at 130 ℃ to obtain a pouring sealant base material;
step 4: 109kg of pouring sealant base material and 7 multiplied by 10 -6 Mixing kg of isopropanol solution of chloroplatinic acid, and stirring for 50min at a stirring speed of 7200rpm to obtain a pouring sealant A component; 113kg of pouring sealant base material, 13kg of polymethylhydrosiloxane and 0.08kg of ethynyl cyclohexanol are mixed, and stirred for 50min at a stirring speed of 7200rpm to obtain a pouring sealant B component;
step 5: taking a PCB, and mixing the component A of pouring sealant and the component B of pouring sealant according to the weight ratio of 1:1.9, uniformly mixing, filling and sealing, and vulcanizing at 80 ℃ for 27h.
Example 6:
step 1: mixing 1.5g of trihydroxy aminomethane with 500g of deionized water, adding 1mol/L dilute hydrochloric acid, regulating the pH value to 8.5, adding 2.3g of dopamine hydrochloride, stirring for 30min, adding 15g of ammonium polyphosphate, performing ultrasonic dispersion treatment for 6h, heating to 65 ℃ in a water bath, standing for 36h, washing, drying and grinding to obtain polydopamine microcapsules;
step 2: dispersing 20g of polydopamine microcapsules in 300g of dimethylformamide, carrying out ultrasonic treatment for 30min, adding 50g of diphenylmethane diisocyanate in a nitrogen environment, heating to 90 ℃, reacting for 12h, washing with dichloromethane, and freeze-drying to obtain modified polydopamine microcapsules;
step 3: reacting 1mol of a, omega-divinyl polydimethylsiloxane with 1mol of diphenylmethane diisocyanate in a nitrogen environment at 0 ℃ for 9 hours to obtain polyurea; 120g of polyurea, 30g of modified polydopamine microcapsule, 15g of white carbon black and 15g of carbon nano tube are kneaded for 5 hours at 140 ℃ to obtain a pouring sealant base material;
step 4: 120kg of pouring sealant base material and 8.5X10 are added -6 Mixing kg of isopropanol solution of chloroplatinic acid, and stirring for 60min at a stirring speed of 8000rpm to obtain a pouring sealant A component; 120kg of pouring sealant base material, 15kg of polymethylhydrosiloxane and 0.1kg of ethynyl cyclohexanol are mixed, and stirred for 60min at a stirring speed of 8000rpm to obtain a pouring sealant B component;
step 5: taking a PCB, and mixing the component A of pouring sealant and the component B of pouring sealant according to the weight ratio of 1:2.3, uniformly mixing, encapsulating, and vulcanizing at 100 ℃ for 30min.
Comparative example 1:
the silicone rubber was not modified and modified polydopamine microcapsules were not added.
Step 1: kneading 100kg of a, omega-divinyl polydimethylsiloxane, 10kg of white carbon black and 10kg of carbon nano tubes for 3 hours at 100 ℃ to obtain a pouring sealant base material;
step 2: 100kg of pouring sealant base material and 1.0X10 are added -6 Mixing kg of isopropanol solution of chloroplatinic acid, and stirring for 30min at a stirring speed of 5000rpm to obtain a pouring sealant A component; mixing 100kg of pouring sealant base material, 8kg of polymethylhydrosiloxane and 0.05kg of ethynyl cyclohexanol, and stirring at a stirring speed of 5000rpm for 30min to obtain a pouring sealant B component;
step 3: taking a PCB, and mixing the component A of pouring sealant and the component B of pouring sealant according to the weight ratio of 1:1, uniformly mixing, encapsulating, and vulcanizing at 50 ℃ for 20 hours.
Comparative example 2:
the polydopamine microcapsules are not modified.
Step 1: mixing 1.1g of trihydroxy aminomethane with 420g of deionized water, adding dilute hydrochloric acid with the concentration of 0.55mol/L, regulating the pH value to 8.1, adding 1.6g of dopamine hydrochloride, stirring for 20min, adding 10.5g of ammonium polyphosphate, performing ultrasonic dispersion treatment for 3h, heating to 55 ℃ in a water bath, standing for 25h, washing, drying and grinding to obtain polydopamine microcapsules;
step 2: reacting 1mol of a, omega-divinyl polydimethylsiloxane with 1mol of diphenylmethane diisocyanate in a nitrogen environment at 0 ℃ for 8.5 hours to obtain polyurea; kneading 110kg of polyurea, 22kg of polydopamine microcapsule, 11kg of white carbon black and 14kg of carbon nano tube for 3-5 hours at 100-140 ℃ to obtain a pouring sealant base material;
step 3: 100kg of pouring sealant base material and 1.5X10 are added -6 Mixing kg of isopropanol solution of chloroplatinic acid, and stirring for 45min at a stirring speed of 5600rpm to obtain a pouring sealant A component; 110kg of pouring sealant base material, 9kg of polymethylhydrosiloxane and 0.06kg of ethynyl cyclohexanol are mixed, and stirred for 45min at a stirring speed of 5600rpm, so that a pouring sealant B component is obtained;
step 5: taking a PCB, and mixing the component A of pouring sealant and the component B of pouring sealant according to the weight ratio of 1:1.1 mixing evenly, filling and sealing, and vulcanizing for 22 hours at 55 ℃.
Comparative example 3:
ammonium polyphosphate was added directly as a flame retardant additive.
Step 1: reacting 1mol of a, omega-divinyl polydimethylsiloxane with 1mol of diphenylmethane diisocyanate in a nitrogen environment at 0 ℃ for 9 hours to obtain polyurea; kneading 105kg of polyurea, 26kg of ammonium polyphosphate, 13kg of white carbon black and 14kg of carbon nano tubes for 4 hours at 120 ℃ to obtain a pouring sealant base material;
step 3: 115kg of pouring sealant base material and 2 multiplied by 10 -6 Mixing kg of isopropanol solution of chloroplatinic acid, and stirring for 40min at a stirring speed of 6000rpm to obtain a pouring sealant A component; mixing 115kg of pouring sealant base material, 7kg of polymethylhydrosiloxane and 0.08kg of ethynyl cyclohexanol, and stirring at a stirring speed of 6000rpm for 50min to obtain a pouring sealant B component;
step 5: taking a PCB, and mixing the component A of pouring sealant and the component B of pouring sealant according to the weight ratio of 1:1.65 are evenly mixed and encapsulated, and vulcanized for 25 hours at 70 ℃.
Experiment:
performance tests were performed on the vulcanized silicone potting gums in examples 1 to 6 and comparative examples 1 to 3, and the experimental results are shown in the following table. Wherein, the liquid crystal display device comprises a liquid crystal display device,
thermal stability: heating to 500 ℃ in a nitrogen environment at a heating rate of 5 ℃/min, and recording the temperature T of 10% of heat loss 10％ ；
Flame retardant properties: testing according to the method specified in UL 94;
tensile strength: according to GB/T1040-92, cutting rubber into dumbbell shape (size of 4 mm. Times.75 mm. Times.2 mm), placing in electronic universal tester (product number AG-201, shimadzu Japan), and performing tensile test at a tensile speed of 100mm/min;
| examples | Flame retardancy | Tensile Strength/MPa | T 10％ /℃ |
| Example 1 | V-0 | 7.5 | 213 |
| Example 2 | V-0 | 7.7 | 221 |
| Example 3 | V-0 | 7.4 | 209 |
| Example 4 | V-0 | 7.7 | 218 |
| Example 5 | V-0 | 7.1 | 216 |
| Example 6 | V-0 | 7.3 | 204 |
| Comparative example 1 | / | 5.1 | 185 |
| Comparative example 2 | V-1 | 6.2 | / |
| Comparative example 3 | V-1 | 5.9 | 190 |
Conclusion:
according to the invention, the polydopamine is adopted to coat the flame retardant ammonium polyphosphate to prepare the microcapsule, and the diphenylmethane diisocyanate is used to modify the polydopamine shell, so that the surface of the polydopamine microcapsule is provided with isocyanate groups; and meanwhile, the urea group is used for functionalizing the silicone rubber, the modified microcapsule is used as a flame retardant material to be added into the urea group functionalized silicone rubber, and the silicone rubber molecular chain and the microcapsule are connected together through a chemical bond, so that the dispersion of the microcapsule is facilitated, and the mechanical property and flame retardant effect of the rubber material are improved. The data of examples 1-6 show that the organosilicon pouring sealant prepared by the invention has good flame retardant property, and the flame retardant grade reaches V-0. The data of example 1, with reference to comparative example 1, shows that the forces between the molecular chains of the ureido-functionalized silicone rubber material are improved and the tensile strength is greater; the silicone rubber prepared in comparative example 1 was extremely flammable, whereas in example 1, the combustibility reached V-0 due to the addition of the flame retardant microcapsules. With reference to comparative example 2, the data of example 2 show that the modified polydopamine microcapsule is more beneficial to improving the dispersibility of the polydopamine microcapsule in ureido-functionalized silicone rubber, so that the flame retardant effect and the tensile strength are better. In comparative example 3, ammonium polyphosphate is directly added as a flame retardant material, and the flame retardant property is poorer than that of example 3, mainly because the dispersibility is poor in the blending process of ammonium polyphosphate and silicone rubber, so that the tensile strength is lower, in addition, the thermal stability of polydopamine is better, and the heat resistance of the silicone rubber can be improved after the addition.
Finally, it should be noted that: the foregoing description is only a preferred embodiment of the present invention, and the present invention is not limited thereto, but it is to be understood that modifications and equivalents of some of the technical features described in the foregoing embodiments may be made by those skilled in the art, although the present invention has been described in detail with reference to the foregoing embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A processing technology of an organic silicon pouring sealant for a PCB circuit board is characterized in that: the method comprises the following steps:
step 1: mixing trihydroxy aminomethane with deionized water, adding dilute hydrochloric acid to adjust the pH value, adding dopamine hydrochloride, stirring, adding ammonium polyphosphate, carrying out ultrasonic treatment, heating to 50-65 ℃ in a water bath, standing for 24-36 h, washing, drying and grinding to obtain polydopamine microcapsules;
step 2: dispersing the polydopamine microcapsule in dimethylformamide, performing ultrasonic treatment, adding diphenylmethane diisocyanate in a nitrogen environment, heating for reaction, washing, and freeze-drying to obtain a modified polydopamine microcapsule;
step 3: reacting a, omega-divinyl polydimethylsiloxane and diphenylmethane diisocyanate to obtain polyurea; kneading polyurea, modified polydopamine microcapsules, white carbon black and carbon nanotubes to obtain a pouring sealant base material;
step 4: mixing pouring sealant base material and isopropyl alcohol solution of chloroplatinic acid, and stirring for 30-60 min at a stirring speed of 5000-8000 rpm to obtain a pouring sealant A component; mixing pouring sealant base material, polymethyl hydrosiloxane and ethynyl cyclohexanol, and stirring for 30-60 min at a stirring speed of 5000-8000 rpm to obtain a pouring sealant B component; and mixing and vulcanizing the component A and the component B of the pouring sealant to obtain the organic silicon pouring sealant for the PCB.
2. The processing technology of the organic silicon pouring sealant for the PCB, which is disclosed in claim 1, is characterized in that: in the step 1, the pH value of the diluted hydrochloric acid is regulated to 8.0-8.5.
3. The processing technology of the organic silicon pouring sealant for the PCB, which is disclosed in claim 1, is characterized in that: in the step 2, the dosages of the components are 10 to 20 parts by weight of polydopamine microcapsule, 200 to 300 parts by weight of dimethylformamide and 30 to 50 parts by weight of diphenylmethane diisocyanate.
4. The processing technology of the organic silicon pouring sealant for the PCB, which is disclosed in claim 1, is characterized in that: in the step 2, the reaction temperature is 80-90 ℃ and the reaction time is 8-12 h; the washing reagent is dichloromethane.
5. The processing technology of the organic silicon pouring sealant for the PCB, which is disclosed in claim 1, is characterized in that: in the step 3, the reaction condition is that the reaction is carried out for 8 to 9 hours in a nitrogen environment at the temperature of 0 ℃; n (a, ω -divinyl polydimethylsiloxane): n (diphenylmethane diisocyanate) =1:1.
6. The processing technology of the organic silicon pouring sealant for the PCB, which is disclosed in claim 1, is characterized in that: in the step 3, the pouring sealant base material comprises 100-120 parts of polyurea, 20-30 parts of modified polydopamine microcapsule, 10-15 parts of white carbon black and 10-15 parts of carbon nano tube by weight.
7. The processing technology of the organic silicon pouring sealant for the PCB, which is disclosed in claim 1, is characterized in that: in the step 3, the kneading temperature is 100-140 ℃, and the kneading time is 3-5 h.
8. The processing technology of the organic silicon pouring sealant for the PCB, which is disclosed in claim 1, is characterized in that: in the step 4, the amount of each component in the pouring sealant A is 100-120 parts by weight of pouring sealant base material and 1.0X10 -6 ～8.5×10 -6 Parts of chloroplatinic acid in isopropanol.
9. The processing technology of the organic silicon pouring sealant for the PCB, which is disclosed in claim 1, is characterized in that: in the step 4, the weight ratio of the pouring sealant A component to the pouring sealant B component is 1: (1-2.3); the vulcanizing condition is that vulcanizing is carried out for 20-30 hours at 50-100 ℃.
10. The silicone pouring sealant for a PCB according to any one of claims 1 to 9, which is prepared by a processing technology of the silicone pouring sealant.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104804705A (en) * | 2015-05-06 | 2015-07-29 | 成都拓利化工实业有限公司 | Low release quantity additive halogen-free flame-retardant heat-conduction organic silicon pouring sealant and preparation method thereof |
| CN106009132A (en) * | 2016-07-04 | 2016-10-12 | 沈阳化工大学 | Preparation method of flame-retardant epoxidized natural rubber composite material |
| CN114044940A (en) * | 2021-10-26 | 2022-02-15 | 南京理工大学 | Microencapsulated flame retardant and preparation method thereof |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104804705A (en) * | 2015-05-06 | 2015-07-29 | 成都拓利化工实业有限公司 | Low release quantity additive halogen-free flame-retardant heat-conduction organic silicon pouring sealant and preparation method thereof |
| CN106009132A (en) * | 2016-07-04 | 2016-10-12 | 沈阳化工大学 | Preparation method of flame-retardant epoxidized natural rubber composite material |
| CN114044940A (en) * | 2021-10-26 | 2022-02-15 | 南京理工大学 | Microencapsulated flame retardant and preparation method thereof |
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