Preparation method of organic silicon flame-retardant sealant

Abstract

According to the technical scheme, a multifunctional reactive flame retardant needs to be prepared firstly, the synthesized multifunctional reactive flame retardant tackifier is more environmentally friendly compared with halogen, phosphate ester and modified substances of the halogen, the phosphate ester and the modified substances of the halogen, the phosphate ester and the modified substances of the halogen, the phosphate ester and the modified substances of the halogen, the phosphate ester and the modified substances of the halogen, the phosphate ester and the modified substances of the halogen, the phosphate ester and the modified substances are added into the prepared sealant to prepare a finished product. And the flame-retardant V-0 level can be reached under the condition of a small addition amount. The multi-branch structure can form physical crosslinking on an organic interface and an inorganic interface and form chemical crosslinking inside, so that the cohesion strength and the interface strength of a cured product are greatly improved. And the extrusion rate, density, hardness, bonding strength, volume resistivity and other performance indexes all meet high requirements in the fields of new energy automobiles and the like.

Description

[Technical field]

[0001] The invention relates to the technical field of polymer flame retardant material sealants, in particular to a low-density and high-strength organic silicon flame retardant sealant. [Background technology]

[0002] The so-called sealant is an adhesive used to fill structural gaps and seal to prevent dust and water. The material is a solidifying material that changes according to the required sealing gap and is not easy to flow. In actual application scenarios, it plays at least one or more roles such as anti-leakage, waterproof, anti-vibration and sound insulation.

[0003] Silicone sealant is a relatively common sealant. It is generally made of polydimethylsiloxane as the main raw material, compounded with cross-linking agents, fillers, plasticizers, coupling agents, catalysts, etc. The flame retardancy of the sealant in the earliest stage is general. In the subsequent improvement process, adding flame retardant powder to the sealant to improve its flame retardant properties is also a common way to improve the sealant.

[0004] However, the addition of the flame retardant powder often increases the density of the sealant, thereby increasing its weight, which not only increases the cost of transportation and installation, but also limits the application scenarios.

[0005] The addition of flame retardants often has an adverse effect on the mechanical properties and bonding properties of sealants. This may cause the sealant to crack, fall off, and other problems during use, affecting its sealing effect and service life.

[0006] Moreover, the ingredients of some flame retardants are not safe enough and may cause harm to human health. For example, phosphate flame retardant is a commonly used fireproof material, but it is easy to volatilize and produce pungent odor and toxic gases during processing. Long-term contact or inhalation of these gases may cause long-term physical harm to human health.

[0007] Although adding halogens to sealants to improve their flame retardant properties is effective, halogen materials produce toxic gases and corrosive harmful substances when burned, which is harmful to the environment and human health and is also undesirable.

[0008] Therefore, how to improve the flame retardancy of sealants based on their characteristics without causing a significant increase in weight or introducing ingredients that are harmful to the human body is the key to improving products. It is also a problem that needs to be solved urgently. [Summary of the invention]

[0009] In view of the above problems, the present invention provides a method for preparing a flame retardant organic silicon material composition as a sealant matrix composition. Polydimethylsiloxane, methyl silicone oil, filler, cross-linking agent, multifunctional reactive flame retardant and pigment are mixed according to the principle of active group equivalence to obtain the required mixture, thereby obtaining a sealant with better environmental protection. Compared with halogen, phosphate ester and its modified products, it is more environmentally friendly and can reach the flame retardant V-0 level with a smaller addition amount. The multi-branch structure can form physical crosslinks at the organic and inorganic interfaces and chemical crosslinks inside, thereby greatly improving the cohesive strength and interface strength of the cured product.

[0010] The present invention relates to a method for preparing a silicone flame retardant sealant, characterized in that the components include:

[0011] Polydimethylsiloxane, molecular weight between 50,000 and 100,000: 25 to 65 parts;

[0012] Methyl silicone oil, molecular weight 50-200: 3-45 parts;

[0013] Filling material: 20-60 parts;

[0014] Multifunctional reactive flame retardant: 1-10 parts

[0015] Cross-linking agent: 0.5-5 parts;

[0016] The above materials are prefabricated and mixed according to proportion to obtain the target product.

[0017] The filler comprises nano calcium carbonate, white carbon black or acetylene black.

[0018] The particle size of the filler is 300-1000 meshes.

[0019] The crosslinking agent is one or more of methyltriacetoxysilane, di-tert-butoxydiacetoxysilane, methyltriethoxysilane, 1,2-bis(triethoxysilyl)ethane, JH-N230, methyltributylacetoximosilane, methylvinylbis(methylisobutylketoxime)silane, methylorthosilicate, etc.

[0020] The sealant component also includes a pigment, and the proportion of the pigment is controlled within the range of 0.01 to 0.2 parts.

[0021] The multifunctional reactive flame retardant is prepared by a coupling reaction between acyl chloride and terminal amino / thiol groups.

[0022] (XN)2PO(C6H6) or (X'-S)2PO(C6H6), where X is

[0023] (CH3O)3Si functional group or benzene ring, and X' is (C2H5O)3Si functional group.

[0024] The prefabrication mixing process includes the following steps:

[0025] Pretreatment: weigh all raw material components in proportion and ensure that solid raw materials such as fillers are dry and free of impurities;

[0026] Mixing equipment: Use planetary mixer or high-speed disperser equipment to ensure that all components are mixed evenly;

[0027] Mixing steps: first, add polydimethylsiloxane and methyl silicone oil into the mixing equipment and stir at a low speed until uniform;

[0028] Then add the filler and gradually increase the stirring speed to evenly disperse the nanofiller in the base polymer;

[0029] Then add the crosslinking agent and the multifunctional reactive flame retardant, and then add the catalyst, and continue stirring until the mixture is in a uniform state.

[0030] After adding the crosslinker and catalyst and continuing to stir, add the pigment and continue stirring until it is completely dispersed.

[0031] A method for preparing a multifunctional reactive flame retardant, characterized in that it comprises the following steps:

[0032] S1: preparing phenylphosphoryl dichloride and a terminal amino / thiol coupling agent in a molar ratio of 1:2 to 1:2.3, wherein the terminal amino / thiol coupling agent is one of γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane or N-phenyl-γ-aminopropyltrimethoxysilane;

[0033] S2: Add γ-mercaptopropyltrimethoxysilane (A-189) and triethylamine to dichloromethane in batches;

[0034] S3: Then slowly add the chloride mixture dropwise at 0-5°C;

[0035] S4: The mixture is stirred at 0-5°C for 2 hours, and then stirred for 5 hours at room temperature or under heating; the heating temperature is one of 25°C, 40°C, 60°C, 70°C, and 80°C;

[0036] S5: After the reaction is completed, the triethylamine hydrochloride is filtered out, and the filtrate is evaporated under vacuum to obtain a crude product of R-FR;

[0037] S6: The crude R-FR product was added with deionized water three times and then purified to obtain the final product, a multifunctional reactive flame retardant.

[0038] Dichloromethane can be replaced by tetrahydrofuran, toluene, chloroform, 1,6-dioxane or n-hexane.

[0039] The chloride mixture in S3 is a mixture of phenylphosphoryl dichloride and dichloromethane.

[0040] The triethylamine can be replaced by di(γ-trimethoxysilylpropyl)amine.

[0041] The product obtained by the preparation method of the multifunctional reactive flame retardant is:

[0042]

[0043] [Specific implementation method]

[0044] The present invention will be described in detail below in conjunction with the embodiments. The following description of the specific embodiments is exemplary and is only used to explain the present invention, and cannot be understood as limiting the present invention.

[0045] The present invention relates to a method for preparing a silicone flame retardant sealant, characterized in that the components include:

[0046] Polydimethylsiloxane, molecular weight between 50,000 and 100,000: 25 to 65 parts;

[0047] Methyl silicone oil, molecular weight 50-200: 3-45 parts;

[0048] Filling material: 20-60 parts;

[0049] Multifunctional reactive flame retardant: 1-10 parts

[0050] Cross-linking agent: 0.5-5 parts;

[0051] The above materials are prefabricated and mixed according to proportion to obtain the target product.

[0052] The filler comprises nano calcium carbonate, white carbon black or acetylene black.

[0053] The particle size of the filler is 300-1000 meshes.

[0054] The crosslinking agent is one or more of methyltriacetoxysilane, di-tert-butoxydiacetoxysilane, methyltriethoxysilane, 1,2-bis(triethoxysilyl)ethane, JH-N230, methyltributylacetoximosilane, methylvinylbis(methylisobutylketoxime)silane, methylorthosilicate, etc.

[0055] The sealant component also includes a pigment, and the proportion of the pigment is controlled within the range of 0.01 to 0.2 parts.

[0056] The multifunctional reactive flame retardant is prepared by a coupling reaction between acyl chloride and terminal amino / thiol groups.

[0057] (XN)2PO(C6H6) or (X'-S)2PO(C6H6), wherein X is a (CH3O)3Si functional group or a benzene ring, and X' is a (C2H5O)3Si functional group.

[0058] The prefabrication mixing process includes the following steps:

[0059] Pretreatment: weigh all raw material components in proportion and ensure that solid raw materials such as fillers are dry and free of impurities;

[0060] Mixing equipment: Use planetary mixer or high-speed disperser equipment to ensure that all components are mixed evenly;

[0061] Mixing steps: first, add polydimethylsiloxane and methyl silicone oil into the mixing equipment and stir at a low speed until uniform;

[0062] Then add the filler and gradually increase the stirring speed to evenly disperse the filler in the base polymer;

[0063] Then add the crosslinking agent and the multifunctional reactive flame retardant, and then add the catalyst, and continue stirring until the mixture is in a uniform state.

[0064] After adding the crosslinker and catalyst and continuing to stir, add the pigment and continue stirring until it is completely dispersed.

[0065] A method for preparing a multifunctional reactive flame retardant, characterized in that it comprises the following steps:

[0066] S1: preparing phenylphosphonic acid dichloride and a terminal amino / thiol coupling agent in a molar ratio of 1:2 to 1:2.3, wherein the terminal amino / thiol coupling agent is one or more of γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane or N-phenyl-γ-aminopropyltrimethoxysilane;

[0067] S2: Add γ-mercaptopropyltrimethoxysilane (A-189) and triethylamine to dichloromethane in batches;

[0068] S3: Then slowly add the chloride mixture dropwise at 0-5°C;

[0069] S4: The mixture is stirred at 0-5°C for 2 hours, and then stirred for 5 hours at room temperature or under heating; the heating temperature is one of 25°C, 40°C, 60°C, 70°C, and 80°C; the specific value of the heating temperature is determined according to the different raw materials selected, and different raw materials have different reaction temperatures.

[0070] S5: After the reaction is completed, the triethylamine hydrochloride is filtered out, and the filtrate is evaporated under vacuum to obtain a crude product of R-FR;

[0071] S6: The crude R-FR product was added with deionized water three times and then purified to obtain the final product, a multifunctional reactive flame retardant.

[0072] The dichloromethane can be replaced by tetrahydrofuran, toluene, chloroform, 1,6-dioxane or n-hexane.

[0073] The chloride mixture in S3 is a mixture of phenylphosphoryl dichloride (0.1 mol) and dichloromethane.

[0074] The product obtained by the preparation method of the multifunctional reactive flame retardant is:

[0075]

[0076]

[0077] Embodiment 1:

[0078] Polydimethylsiloxane (75000cps): 45 parts;

[0079] Methyl silicone oil (100cps): 20 parts;

[0080] The filler is nano calcium carbonate (500 mesh): 40 parts; the multifunctional reactive flame retardant: 6 parts; the crosslinking agent is methyl triacetoxy silane: 2 parts; and the pigment is added as needed: 0.1 parts;

[0081] The above materials are prefabricated and mixed according to the proportion to obtain the target product. The specific prefabrication and mixing process is as follows:

[0082] Pretreatment: Classify and weigh the main raw materials according to the proportions, and ensure that solid raw materials such as fillers are dry and free of impurities.

[0083] Mixing equipment: Use planetary mixer or high-speed disperser and other equipment to ensure that the mixing process is uniform and meets the process requirements.

[0084] Mixing steps: First, add 45 parts of polydimethylsiloxane (75000 cps) and 20 parts of methyl silicone oil (100 cps) into a mixing device and stir at a low speed until uniform.

[0085] Add filler: According to the selected material, add 40 parts of 500-mesh nano calcium carbonate and gradually increase the stirring speed to evenly disperse the filler in the base polymer.

[0086] Then, 2 parts of methyltriacetoxysilane as a crosslinking agent and 6 parts of a multifunctional reactive flame retardant were added, followed by the catalyst, and stirring was continued until the mixture was in a uniform state.

[0087] Add auxiliary materials: Add 0.1 parts of pigment, add it at this time, and continue stirring until it is completely dispersed.

[0088] The finished product parameters of the obtained silicone flame retardant sealant are: extrusion rate 180g / 60s, density 1.30g / cm 3 , 30D, bonding strength 3.5Mpa, volume resistivity 1.5*10 14 Ω·cm, flame retardant grade is V-0, reliability 1. High temperature and high humidity 1000h: bonding strength 3.2Mpa; 2. Hot and cold shock 1000h: bonding strength 3.4Mpa.

[0089] Embodiment 2:

[0090] Polydimethylsiloxane (50000cps): 65 parts;

[0091] Methyl silicone oil (50cps): 30 parts;

[0092] Filler: 25 parts of white carbon black (800 mesh);

[0093] Multifunctional reactive flame retardant: 3 parts;

[0094] The crosslinking agent is 1.5 parts of di-tert-butoxy diacetoxy silane and 1.5 parts of methyl triethoxy silane, which together make 3 parts;

[0095] Then add pigment as needed: 0.05 parts;

[0096] The above materials are prefabricated and mixed according to proportion to obtain the target product.

[0097] The specific prefabrication mixing process is:

[0098] Pretreatment: Classify and weigh the main raw materials according to the proportions, and ensure that solid raw materials such as fillers are dry and free of impurities.

[0099] Mixing equipment: Use planetary mixer or high-speed disperser and other equipment to ensure that the mixing process is uniform and meets the process requirements.

[0100] Mixing steps: First, add 65 parts of polydimethylsiloxane (50,000 cps) and 30 parts of methyl silicone oil (50 cps) into a mixing device and stir at a low speed until uniform.

[0101] Add filler: According to the selected material, add 25 parts of 800 mesh white carbon black, and gradually increase the stirring speed to make the filler evenly dispersed in the base polymer.

[0102] Then, 1.5 parts of methyltriacetoxysilane and 1.5 parts of di-tert-butoxydiacetoxysilane were added as crosslinking agents, 3 parts of multifunctional reactive flame retardant, and then a catalyst was added, and stirring was continued until the mixture was in a uniform state.

[0103] Add auxiliary materials: Add 0.05 parts of pigment, add it at this time, and continue stirring until it is completely dispersed.

[0104] The finished product parameters of the obtained silicone flame retardant sealant are: extrusion rate 200g / 60s, density 1.28g / cm 3 , degree is 28D, bonding strength is 3.2Mpa, volume resistivity is 1.2*10 14 Ω·cm, flame retardant grade is V-1, reliability 1. High temperature and high humidity 1000h: bonding strength 3.0Mpa; 2. Hot and cold shock 1000h: bonding strength 3.2Mpa.

[0105] Embodiment 3:

[0106] Polydimethylsiloxane (100000cps): 25 parts;

[0107] Methyl silicone oil (200cps): 45 parts;

[0108] The filler is acetylene black (300 mesh): 60 parts;

[0109] Multifunctional reactive flame retardant: 10 parts;

[0110] Crosslinking agent: 4 parts, including 2 parts of 1,2-bis(triethoxysilyl)ethane and 2 parts of methyltributylidene oxime silane;

[0111] Then add pigment as needed: 0.2 parts;

[0112] The above materials are prefabricated and mixed according to proportion to obtain the target product.

[0113] The specific prefabrication mixing process is:

[0114] Pretreatment: Classify and weigh the main raw materials according to the proportions, and ensure that solid raw materials such as fillers are dry and free of impurities.

[0115] Mixing equipment: Use planetary mixer or high-speed disperser and other equipment to ensure that the mixing process is uniform and meets the process requirements.

[0116] Mixing steps: First, add 25 parts of polydimethylsiloxane (100,000 cps) and 45 parts of methyl silicone oil (200 cps) into a mixing device and stir at a low speed until uniform.

[0117] Add filler: According to the selected material, add 60 parts of 300 mesh acetylene carbon black, and gradually increase the stirring speed to make the filler evenly dispersed in the base polymer.

[0118] Then, 2 parts of 1,2-bis(triethoxysilyl)ethane and 2 parts of methyltributylidene oxime silane were added as crosslinking agents, 10 parts of multifunctional reactive flame retardant, and then a catalyst was added, and stirring was continued until the mixture was in a uniform state.

[0119] Add auxiliary materials: Add 0.2 parts of pigment, add it at this time, and continue stirring until it is completely dispersed.

[0120] The finished product parameters of the obtained silicone flame retardant sealant are: extrusion rate 250g / 60s, density 1.35g / cm 3 , 35D, bonding strength 4.0Mpa, volume resistivity 2.0*10 14 Ω·cm, flame retardant grade is V-0, reliability 1. High temperature and high humidity 1000h: bonding strength 3.7Mpa; 2. Hot and cold shock 1000h: bonding strength 3.8Mpa.

[0121] The low-density and high-strength silicone flame-retardant sealant involved has the following significant advantages over traditional flame-retardant sealants:

[0122] Environmental protection: Synthetic reactive flame retardant adhesion promoter is more environmentally friendly than halogen, phosphate ester and its modified products.

[0123] Flame retardant performance: flame retardant V-0 level can be achieved with a relatively small addition amount.

[0124] Mechanical properties: The multi-branch structure can form physical cross-links at the organic and inorganic interfaces and chemical cross-links internally, greatly improving the cohesive strength and interfacial strength of the cured product.

[0125] Comprehensive performance: performance indicators such as extrusion rate, density, hardness, bonding strength, volume resistivity, etc. all meet the high requirements of new energy vehicles and other fields.

[0126] Specifically, the organic silicon material flame retardant sealant composition provided by the present invention has an extrusion rate of 150-250 g / 60 s, a density of 1.25-1.35, a hardness of 25-35 D, a bonding strength of 3-4 MPa, and a volume resistivity of 1-2*10 14 Ω·cm, reliability: meet the requirements of thermal shock, high temperature and high humidity for 1000h (attenuation of main performance indicators ≤10%), flame retardant grade V-0.

[0127] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention is disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent changes and modifications made to the above embodiments according to the technology of the present invention are within the scope of the technical solution of the present invention without departing from the content of the technical solution of the present invention.

Claims

1. A method for preparing a silicone flame retardant sealant, characterized in that: The components include: Polydimethylsiloxane, molecular weight between 50,000 and 100,000: 25 to 65 parts; Methyl silicone oil, molecular weight 50-200: 3-45 parts; Filling material: 20-60 parts; Multifunctional reactive flame retardant: 1-10 parts Cross-linking agent: 0.5-5 parts; The above materials are prefabricated and mixed according to proportion to obtain the target product.

2. The method for preparing a flame retardant silicone sealant according to claim 1, characterized in that: The filler comprises nano calcium carbonate, white carbon black or acetylene carbon black; and the particle size of the filler is 300-1000 meshes.

3. The method for preparing an organosilicon sealant according to claim 2, characterized in that: The crosslinking agent is one or more of methyltriacetoxysilane, di-tert-butoxydiacetoxysilane, methyltriethoxysilane, 1,2-bis(triethoxysilyl)ethane, methyltributylacetoximosilane, methylvinylbis(methylisobutylketoxime)silane, methylorthosilicate and the like.

4. The method for preparing an organosilicon sealant according to claim 3, characterized in that: The sealant component also includes a pigment, and the proportion of the pigment is controlled within the range of 0.01 to 0.2 parts.

5. The method for preparing an organosilicon sealant according to claim 4, characterized in that: The multi-branch flame retardant tackifier is (XN)2PO(C6H6) or (X'-S)2PO(C6H6) prepared by the coupling reaction of acyl chloride and terminal amino group / thiol group, wherein X is a (CH3O)3Si functional group or a benzene ring, and X' is a (C2H5O)3Si functional group.

6. The method for preparing an organosilicon sealant according to claim 5, characterized in that: The prefabrication mixing process includes the following steps: Pretreatment: weigh all raw material components in proportion and ensure that solid raw materials such as fillers are dry and free of impurities; Mixing equipment: Use planetary mixer or high-speed disperser to ensure that all components are mixed evenly; Mixing steps: First, add polydimethylsiloxane and methyl silicone oil into the mixing equipment and stir at low speed until uniform; Then add the filler and gradually increase the stirring speed to evenly disperse the filler in the base polymer; then add the crosslinking agent and multifunctional reactive flame retardant, followed by the catalyst, and continue stirring until the mixture is uniform.

7. The method for preparing an organosilicon sealant according to claim 6, characterized in that: After adding the crosslinker and catalyst and continuing to stir, add the pigment and continue stirring until it is completely dispersed.

8. A method for preparing a multifunctional reactive flame retardant, characterized in that: The following steps are involved: S1: preparing phenylphosphonic acid dichloride and a terminal amino / thiol coupling agent in a molar ratio of 1:2 to 1:2.3, wherein the terminal amino / thiol coupling agent is one or more of γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-ureidopropyltrimethoxysilane or N-phenyl-γ-aminopropyltrimethoxysilane; S2: adding γ-mercaptopropyltrimethoxysilane and triethylamine to dichloromethane in batches; S3: Then slowly add the chloride mixture dropwise at 0-5°C; S4: The mixture is stirred at 0-5°C for 2 hours, and then stirred for 5 hours at room temperature or under heating; The heating temperature is one of 25°C, 40°C, 60°C, 70°C, and 80°C; S5: After the reaction is completed, the triethylamine hydrochloride is filtered out, and the filtrate is evaporated under vacuum to obtain a crude product of R-FR; S6: The crude R-FR product was added with deionized water three times and then purified to obtain the final product, a multifunctional reactive flame retardant.

9. The method for preparing the multifunctional reactive flame retardant according to claim 8, characterized in that: The dichloromethane can be replaced by tetrahydrofuran, toluene, chloroform, 1,6-dioxane or n-hexane.

10. The method for preparing a multifunctional reactive flame retardant according to claim 7, characterized in that: The chloride mixture in S3 is a mixture of phenylphosphoryl dichloride and dichloromethane.

11. The method for preparing the multi-branch flame retardant tackifier according to claim 7, characterized in that: The product obtained by the preparation method of the multifunctional reactive flame retardant is:

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