Silane-modified two-component flame-retardant adhesive and preparation method thereof

Abstract

This application discloses a silane-modified two-component flame-retardant adhesive and its preparation method. The flame-retardant adhesive includes component A and component B. Component A includes 200-400 parts of silane-modified polyether, 100-200 parts of flame-retardant plasticizer, 1300-400 parts of filler, 3-10 parts of UV absorber, 3-10 parts of light stabilizer, 15-35 parts of thixotropic agent, 30-50 parts of silane coupling agent, 10-40 parts of first curing agent, 10-20 parts of curing accelerator, and 5-15 parts of dehydrating agent. Component B includes 300-500 parts of epoxy resin, 1250-350 parts of filler, and 2... 150-250 parts, flame retardant plasticizer 250-350 parts, deionized water 5-15 parts and second curing agent 20-40 parts, filler 2 is epoxy resin-SiO2 microcapsule modified ammonium polyphosphate. The modified ammonium polyphosphate has increased flame retardant efficiency, improved compatibility and increased migration resistance of flame retardant adhesive.

Description

Technical Field

[0001] This application relates to the field of silane-modified sealants, and in particular to a silane-modified two-component flame-retardant adhesive and its preparation method. Background Technology

[0002] Silane-modified sealants combine the advantages of silicone and polyurethane sealants, exhibiting broad adhesion and low VOC emissions, making them widely used in various industrial fields. However, the sealants themselves have poor flame retardant properties and are easily ignited when exposed to open flames or high temperatures. With increasingly stringent requirements for flame retardancy and ever-accelerating production cycles, the overall performance of single-component sealants can no longer meet all process requirements.

[0003] Therefore, two-component sealants with flame-retardant properties are receiving increasing attention in the market. Flame-retardant sealants usually contain inorganic phosphorus-based or organic phosphorus-based flame retardants. In order to enhance the flame-retardant efficiency, the amount of flame retardant added is generally large. However, as the amount added increases, the mechanical properties of the flame-retardant sealant decrease significantly. Furthermore, phosphorus-based flame retardants also have problems such as poor compatibility, high volatility, and dripping during combustion. Summary of the Invention

[0004] To address the problems of poor flame retardant performance of flame-retardant sealants, reduced strength due to excessive addition of flame retardants, poor compatibility of flame retardants in sealants, and easy volatilization and precipitation of flame retardants, this application provides a silane-modified two-component flame-retardant adhesive and its preparation method.

[0005] In a first aspect, this application provides a silane-modified two-component flame retardant adhesive, comprising component A and component B, wherein component A and component B comprise the following raw materials in parts by weight:

[0006] Component A:

[0007] 200-400 parts of silane-modified polyether;

[0008] 100-200 parts of flame retardant plasticizer;

[0009] Filler 1: 300-400 parts;

[0010] UV absorber 3-10;

[0011] Light stabilizer 3-10;

[0012] Thixotropic agent 15-35 parts;

[0013] 30-50 parts of silane coupling agent;

[0014] 10-40 parts of the first curing agent;

[0015] 10-20 parts of curing accelerator;

[0016] 5-15 parts of dehydrating agent;

[0017] Component B:

[0018] 300-500 parts of epoxy resin;

[0019] Filler 1: 250-350 parts;

[0020] Filler 2: 150-250 parts;

[0021] 250-350 parts of flame retardant plasticizer;

[0022] Deionized water 5-15;

[0023] 20-40 parts of the second curing agent;

[0024] The filler 2 is epoxy resin-SiO2 microcapsule modified ammonium polyphosphate.

[0025] Preferably, the epoxy resin includes one or a combination of several of the following: bisphenol A type epoxy resin, bisphenol F type epoxy resin, polyphenol type glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, glycidyl ester type epoxy resin, and glycidyl amine type epoxy resin.

[0026] Preferably, the ultraviolet absorber includes one or a combination of several of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, and 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole.

[0027] Preferably, the light stabilizer comprises one or a combination of several of the following: bis-2,2,6,6-tetramethylpiperidinol sebacate, bis(1,2,2,6,6-pentamethylpiperidinol) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidinol) sebacate, and 1-methyl-8-(1,2,2,6,6-pentamethyl-4-piperidinol) sebacate.

[0028] Preferably, the thixotropic agent includes one or a combination of several of polyamide wax, hydrogenated castor oil, and fumed silica.

[0029] Preferably, the silane coupling agent includes one or a combination of several of γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane, phenylamino-silane, triaminosilane, γ-mercaptopropyltrimethoxysilane, γ-ureapropyltrimethoxysilane, γ-ureapropyltrihexyloxysilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-glycidyl ether propyltrimethoxysilane.

[0030] Preferably, the first curing agent includes one or a combination of several of ethylenediamine, diethylenetriamine, polyethylenepolyamine, m-phenylenediamine, m-phenylenediamine, amine addition curing agents, and phenolic amino alcohol curing agents.

[0031] Preferably, the curing accelerator includes one or a combination of several of 2,4,6-tris(dimethylaminomethyl)phenol, triethylamine, triethanolamine, benzyl dimethylamine, 1,8-diazacyclo[5,4,0]undecene-7, and o-hydroxybenzyl dimethylamine.

[0032] Preferably, the dehydrating agent includes one or a combination of vinyltrimethoxysilane and vinyltriethoxysilane.

[0033] Preferably, the second curing agent includes one or more of bis(acetylacetonate) dibutyltin and dibutyltin laurate.

[0034] Preferably, the volume ratio of component A to component B is 1:(1-5).

[0035] By adopting the above technical solution, the silane-modified polyether in component A has polyether as the long chain and silane-oxygen end caps. After room temperature humidity curing, the silane-modified polyether sealant will form a network structure with flexible polyether long chains connected by siloxane-silicon bonds as crosslinking points. The non-polar structure of polyether determines its low cohesive energy and low strength. When mixed with epoxy resin in component B, it will form an island structure. The epoxy resin is distributed in the silane-modified polyether. Its high strength after curing and high adhesion to the substrate make the overall flame retardant adhesive performance more stable. It can make up for the lack of strength of polyether itself and obtain a flame retardant sealant with excellent physical and chemical properties.

[0036] Preferably, the flame retardant plasticizer includes one or a combination of several of the following: tri(2-chloroethyl) phosphate, tri(2-chloropropyl) phosphate, triethyl phosphate, triphenyl phosphate, tri(1,3-dichloroisopropyl) phosphate, tributoxyethyl phosphate, and toluene diphenyl phosphate.

[0037] Preferably, the filler 1 comprises one or a combination of several of aluminum hydroxide, magnesium hydroxide, expanded graphite, borate, aluminum oxalate, and zinc sulfate.

[0038] By adopting the above technical solution, the flame-retardant plasticizer is a phosphate ester-based organophosphorus flame retardant. The coating layer formed by phosphoric acid provides a covering effect, isolating the high heat of combustion from contact with flammable gases. Simultaneously, the generated polymetaphosphoric acid, a strong acid, acts as a powerful dehydrating agent, enabling the polymer to dehydrate and carbonize. Especially in silane-modified polyethers and epoxy resins containing oxygen-containing groups, the addition of phosphate ester-based organic flame retardants can significantly enhance the flame-retardant effect. Meanwhile, filler 1 acts as a flame-retardant synergist, exhibiting high stability and providing durable burning resistance. Its synergy with the organophosphorus flame retardant enhances the flame-retardant effect without affecting the mechanical properties of the resulting flame-retardant adhesive.

[0039] Preferably, the raw materials for the epoxy resin-SiO2 microcapsule modified ammonium polyphosphate include epoxy resin, tetraethyl orthosilicate and ammonium polyphosphate in a mass ratio of (0.1-0.3):(0.15-0.25):1.

[0040] Preferably, the epoxy resin is a bisphenol A type epoxy resin, and the epoxy value of the epoxy resin is 0.4 to 0.54.

[0041] Preferably, the ammonium polyphosphate is a type II long-chain ammonium polyphosphate.

[0042] Ammonium polyphosphate is a highly efficient inorganic flame retardant with a high decomposition temperature. During combustion, the phosphoric acid produced can coat the surface of the insulation layer, forming a char layer with the polymer. This char layer insulates against heat while reducing oxygen supply, thus preventing further combustion. During combustion, ammonium polyphosphate also produces inert gases such as ammonia, which significantly dilutes the concentration of combustible gases, acting as a gas-phase flame retardant. The nitrogen it contains also decomposes rapidly, absorbing a large amount of heat. However, as an acid source, some ammonium polyphosphate undergoes esterification with the fillers in the flame-retardant adhesive, disrupting the formation of the char layer during combustion and reducing its flame-retardant efficiency. Furthermore, ammonium polyphosphate has poor migration and water resistance; after a period of time, it will precipitate onto the surface or react with water. Moisture absorption by ammonium polyphosphate will cause the flame-retardant adhesive to lose its flame-retardant effect.

[0043] By adopting the above technical solution, epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate can protect ammonium polyphosphate from reacting with the hydroxyl groups on the surface of the filler in the system, thus preventing it from losing its flame-retardant effect. The coating layer of epoxy resin-SiO2 microcapsules can effectively inhibit the contact and reaction between ammonium polyphosphate and water. The epoxy resin on the surface of ammonium polyphosphate can increase the compatibility between ammonium polyphosphate and polymers and improve the migration resistance of ammonium polyphosphate. SiO2 nanoparticles covering the surface of ammonium polyphosphate will generate a significant inorganic barrier during combustion, preventing the degradation of ammonium polyphosphate and further increasing the thickness and mechanical strength of the char layer. The epoxy resin coating layer can increase the thermal stability of ammonium polyphosphate. The synergistic effect between phosphorus-containing flame retardants and silicon-containing compounds can effectively prevent fire and isolate flame spread, effectively improving flame-retardant efficiency.

[0044] Furthermore, the epoxy resin on the surface of the epoxy resin-SiO2 microcapsule modified ammonium polyphosphate can crosslink with the silane-modified polyether in the middle of component A to form a crosslinked network structure. On the one hand, this can prevent the ammonium polyphosphate flame retardant from precipitating onto the surface of the flame retardant adhesive. On the other hand, it increases the crosslinking density inside the flame retardant adhesive. The flame retardant plasticizers in components A and B are easily volatilized and tend to drip after combustion. The dripping flames and burning materials may cause secondary ignition. Increasing the crosslinking density inside the flame retardant adhesive can effectively inhibit the volatilization of the flame retardant plasticizer and enhance the density of the flame retardant adhesive, making it less prone to dripping and smoldering during combustion.

[0045] Preferably, the epoxy resin-SiO2 microcapsule modified ammonium polyphosphate is prepared according to the following method:

[0046] S1. Add distilled water to the solvent, mix well, add sodium polyphosphate, dispersant and catalyst 1, stir and mix at 35-45℃ for 15-20 min, then add tetraethyl orthosilicate, react at 40-50℃ for 3-5 h, and then filter, wash and dry to obtain modified ammonium polyphosphate pre-reactant.

[0047] S2. Add epoxy resin, curing agent, modified ammonium polyphosphate pre-reactant, dispersant and catalyst 2 to the solvent in sequence, stir and disperse for 20-40 min, heat the solution to 80-90℃, stir and react for 2-3 h, and after the reaction is completed, filter, wash and dry to obtain epoxy resin-SiO2 microcapsule modified ammonium polyphosphate.

[0048] Preferably, the dispersant comprises one or a combination of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate; the curing agent comprises one or a combination of triethylenetetramine, ethylenediamine, diethylenetriamine, tetraethylenepentamine, m-phenylenediamine, and m-phthalamide.

[0049] Preferably, the solvent includes one or more of anhydrous ethanol and methanol.

[0050] Preferably, catalyst 1 is ammonia; catalyst 2 is one or a combination of several of N,N-dimethylcyclohexylamine, bis(2-dimethylaminoethyl) ether, triethylenediamine, N,N,N',N'-tetramethylalkylenediamine, N,N,N',N”-pentamethyldiethylenetriamine, triethylamine, N,N-dimethylbenzylamine, N,N-dimethylhexadecylamine, and N,N-dimethylbutylamine.

[0051] Preferably, the amount of dispersant added is 0.5 to 2.5% of the mass of ammonium polyphosphate, and the amount of curing agent added is 5 to 20% of the mass of epoxy resin.

[0052] Preferably, the mass ratio of solvent to ammonium polyphosphate in step S1 is (2.5-3.5):1; and the mass ratio of solvent to modified ammonium polyphosphate pre-reactant in step S2 is (2-2.8):1.

[0053] Preferably, the amount of catalyst 1 added is 35-45% of the mass of ammonium polyphosphate; the amount of catalyst 2 added is 1-2% of the mass of the modified ammonium polyphosphate pre-reactant.

[0054] By adopting the above technical solution, tetraethyl orthosilicate first forms a nano-silica coating layer on the surface of ammonium polyphosphate, which acts as an inorganic barrier. During combustion, this layer inhibits the degradation of polyphosphate and increases the thickness of the char layer, thereby enhancing the flame-retardant effect. Then, an epoxy resin layer is coated onto the surface. The epoxy resin has good compatibility with the substrate and can form a cross-linked network structure with silane-modified polyether, increasing the density of the flame-retardant adhesive and inhibiting the precipitation of flame retardants and dripping after combustion.

[0055] Secondly, this application also provides a method for preparing a silane-modified two-component flame-retardant adhesive, comprising the following steps:

[0056] Preparation of Component A: The silane-modified polyether, flame retardant plasticizer, filler 1, ultraviolet absorber, light stabilizer and thixotropic agent are mixed and stirred at 1000-1200 rpm for 0.5-1 h under vacuum at 90-100℃. Then the mixture is cooled to 40-50℃, and the silane coupling agent, first curing agent, curing accelerator and dehydrating agent are added. After stirring evenly, Component A is obtained. Preparation of Component B: The epoxy resin, filler 1, filler 2, flame retardant plasticizer, deionized water and second curing agent are stirred evenly under vacuum to obtain Component B.

[0057] Preferably, the vacuum degree under the vacuum conditions is -0.09 to -0.1 MPa.

[0058] In summary, this application has the following beneficial effects:

[0059] 1. The silane-modified polyether contained in component A of this application can form an island structure with the epoxy resin in component B. The high strength of the epoxy resin can compensate for the problem of insufficient cohesive energy caused by the non-polar structure of the polyether, thereby enhancing the performance of the flame-retardant sealant and its adhesion to the substrate.

[0060] 2. Component B of this application contains epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate. During combustion, the ammonium polyphosphate, together with the flame retardant plasticizer present in the system, can form a phosphate coating layer, which can effectively insulate heat and reduce oxygen supply. The generated ammonia gas is an inert gas that plays a role in gas-phase flame retardancy. Through further modification of the epoxy resin-SiO2 microcapsules, on the one hand, the compatibility between ammonium polyphosphate and polymer can be increased, and the coating layer can effectively inhibit the direct contact of ammonium polyphosphate with water, preventing it from losing its flame retardancy after absorbing moisture, and can also increase the migration resistance of sodium polyphosphate. On the other hand, the silica contained in the coating layer can form a significant inorganic barrier during combustion while playing a barrier and protective role, forming a carbon layer on the surface to enhance the flame retardant efficiency.

[0061] 3. Epoxy resin-SiO2 microcapsule modified ammonium polyphosphate can also crosslink with the silane-modified polyether in component A to form a network structure, which can effectively inhibit the volatilization of flame retardant plasticizers and the precipitation of ammonium polyphosphate. At the same time, after increasing the density of the flame retardant sealant through crosslinking, it can effectively inhibit the burning drip phenomenon caused by flame retardant plasticizers and prevent secondary ignition. Detailed Implementation

[0062] Preparation example of epoxy resin-SiO2 microcapsule modified ammonium polyphosphate

[0063] Preparation Example 1: An epoxy resin-SiO2 microcapsule modified ammonium polyphosphate was prepared according to the following method:

[0064] S1. Add 100g of distilled water to 300g of anhydrous ethanol, mix well, then add 100g of ammonium polyphosphate (ammonium polyphosphate is a type II long-chain polyphosphate with an average degree of polymerization of 1500), 2g of sodium dodecyl sulfate and 40g of ammonia water, stir and mix at 40℃ for 20min, then add 20g of tetraethyl orthosilicate, react at 50℃ for 4h, and then filter, wash and dry to obtain the modified ammonium polyphosphate pre-reactant.

[0065] S2. Add 20g of epoxy resin E51 (epoxy value 0.48-0.54), 2g of triethylenetetramine, 100g of modified ammonium polyphosphate pre-reactant, 1g of sodium dodecylbenzenesulfonate and 2g of N,N-dimethylcyclohexylamine to 240g of anhydrous ethanol in sequence. Stir and disperse for 30min. Heat the solution to 90℃ and stir for 3h. After the reaction is completed, filter, wash and dry to obtain epoxy resin-SiO2 microcapsule modified ammonium polyphosphate.

[0066] Preparation Example 2: An epoxy resin-SiO2 microcapsule modified ammonium polyphosphate, which differs from Preparation Example 1 only in that the amount of tetraethyl orthosilicate added is 10g.

[0067] Preparation Example 3 is an epoxy resin-SiO2 microcapsule modified ammonium polyphosphate, which differs from Preparation Example 1 only in that the amount of tetraethyl orthosilicate added is 30g.

[0068] Preparation Example 4: An epoxy resin-SiO2 microcapsule modified ammonium polyphosphate, which differs from Preparation Example 1 only in that the amount of epoxy resin E51 added is 15g.

[0069] Preparation Example 5: An epoxy resin-SiO2 microcapsule modified ammonium polyphosphate, which differs from Preparation Example 1 only in that the amount of epoxy resin E51 added is 25g.

[0070] Preparation Example 6: An epoxy resin-SiO2 microcapsule modified ammonium polyphosphate, which differs from Preparation Example 1 only in that the amount of tetraethyl orthosilicate added is 8g.

[0071] Preparation Example 7: An epoxy resin-SiO2 microcapsule modified ammonium polyphosphate, which differs from Preparation Example 1 only in that the amount of tetraethyl orthosilicate added is 35g.

[0072] Preparation Example 8: An epoxy resin-SiO2 microcapsule modified ammonium polyphosphate, which differs from Preparation Example 1 only in that the amount of epoxy resin E51 added is 12g.

[0073] Preparation Example 9: An epoxy resin-SiO2 microcapsule modified ammonium polyphosphate, which differs from Preparation Example 1 only in that the amount of epoxy resin E51 added is 30g.

[0074] Preparation Example 10, an epoxy resin-SiO2 microcapsule modified ammonium polyphosphate, differs from Preparation Example 1 in that it is prepared according to the following method:

[0075] Add 100g of distilled water to 300g of anhydrous ethanol, mix well, then add 100g of ammonium polyphosphate, 2g of sodium dodecyl sulfate and 40g of ammonia water. Stir and mix at 40℃ for 20min, then add 20g of tetraethyl orthosilicate, react at 50℃ for 4h, and then filter, wash and dry to obtain SiO2 modified ammonium polyphosphate.

[0076] Preparation Example 11, an epoxy resin-SiO2 microcapsule modified ammonium polyphosphate, differs from Preparation Example 1 in that it is prepared according to the following method:

[0077] 20g of epoxy resin E51 (epoxy value 0.48-0.54), 2g of triethylenetetramine, 100g of ammonium polyphosphate and 1g of sodium dodecylbenzenesulfonate were added sequentially to 240g of anhydrous ethanol and stirred and dispersed for 30min. The solution was heated to 50℃ and stirred for 3h. After the reaction was completed, the epoxy resin modified ammonium polyphosphate was obtained by filtration, washing and drying.

[0078] Example

[0079] Example 1: A silane-modified two-component flame retardant adhesive was prepared according to the following method:

[0080] Preparation of Component A: 3 kg of silane-modified polyether (model SAX400), 1.5 kg of triethyl phosphate, 3.5 kg of aluminum hydroxide, 0.07 kg of 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 0.07 kg of light stabilizer 292, and 0.25 kg of polyamide wax (molecular weight 500-800) were mixed and stirred at 1000 rpm for 1 h under vacuum at 100°C. Then, the mixture was cooled to 40°C, and 0.4 kg of γ-aminopropyltrimethoxysilane, 0.25 kg of ethylenediamine, 0.15 kg of triethanolamine, and 0.1 kg of vinyltrimethoxysilane were added. After stirring evenly, Component A was obtained.

[0081] Preparation of Component B: 4 kg of epoxy resin E51 (epoxy value 0.48-0.54), 3 kg of aluminum hydroxide, 2 kg of epoxy resin-SiO2 microcapsule modified ammonium polyphosphate prepared in Preparation Example 1, 3 kg of triphenyl phosphate, 0.1 kg of deionized water, and 0.3 kg of bis(acetylacetonate) dibutyltin were stirred and mixed evenly under vacuum to obtain Component B.

[0082] The vacuum level under vacuum conditions is -0.1 MPa.

[0083] Examples 2-19 describe a silane-modified two-component flame retardant adhesive, differing from Example 1 only in the proportions of the raw materials used, as shown in Table 1.

[0084] Formulations of Examples 1-19

[0085]

[0086]

[0087]

[0088] In this example, Examples 2 and 3 used the epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Example 2; Examples 8 and 9 used the epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Example 3; Examples 10 and 11 used the epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Example 4; and Examples 12 and 13 used the epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Example 5.

[0089] Example 20, a silane-modified two-component flame retardant adhesive, differs from Example 1 only in that an equal amount of epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Preparation Example 6 is used instead of the epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Preparation Example 1.

[0090] Example 21, a silane-modified two-component flame retardant adhesive, differs from Example 1 only in that an equal amount of epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Preparation Example 7 is used instead of the epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Preparation Example 1.

[0091] Example 22, a silane-modified two-component flame retardant adhesive, differs from Example 1 only in that an equal amount of epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Preparation Example 8 is used instead of the epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Preparation Example 1.

[0092] Example 23, a silane-modified two-component flame retardant adhesive, differs from Example 1 only in that an equal amount of epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Preparation Example 9 is used instead of the epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Preparation Example 1.

[0093] Example 24: A silane-modified two-component flame retardant adhesive, differing from Example 1 only in that, during the preparation of component A, the amount of aluminum hydroxide added is 2.8 kg; and during the preparation of component B, the amount of aluminum hydroxide added is 2.2 kg.

[0094] Example 25: A silane-modified two-component flame retardant adhesive, differing from Example 1 only in that, during the preparation of component A, the amount of aluminum hydroxide added is 4.2 kg; and during the preparation of component B, the amount of aluminum hydroxide added is 2.8 kg.

[0095] Comparative Example

[0096] Comparative Example 1, a silane-modified two-component flame retardant adhesive, differs from Example 1 only in that the amount of epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate added in Preparation Example 1 is 1.2 kg.

[0097] Comparative Example 2, a silane-modified two-component flame retardant adhesive, differs from Example 1 only in that the amount of epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate added in Preparation Example 1 is 2.8 kg.

[0098] Comparative Example 3, a silane-modified two-component flame retardant adhesive, differs from Example 1 only in that an equal amount of epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Preparation Example 10 is used instead of the epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Preparation Example 1.

[0099] Comparative Example 4, a silane-modified two-component flame retardant adhesive, differs from Example 1 only in that an equal amount of epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Preparation Example 11 is used instead of epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Preparation Example 1.

[0100] Comparative Example 5 is a silane-modified two-component flame retardant adhesive, which differs from Example 1 only in that an equal amount of ammonium polyphosphate is used to replace the epoxy resin-SiO2 microcapsule-modified ammonium polyphosphate prepared in Example 1.

[0101] Performance testing

[0102] 1. Flame retardant performance test: According to GB / T 13488-92 "Determination of the flammability of rubber by vertical burning method", the flame retardant level is rated according to this standard and the phenomenon of dripping material igniting cotton is tested.

[0103] 2. Mechanical property test: According to GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", the tensile strength (MPa) of the sample after curing for 7 days under standard conditions at a temperature of (23±2)℃ is tested, and the sample is prepared according to standard type I.

[0104] 3. Migration resistance test: The sample was coated on the surface of an aluminum alloy plate with a thickness of 2±0.5mm. After curing under the same curing conditions for 7 days, it was placed in the same environment for 28 days. The precipitation on the sample surface was compared and divided into 5 levels: no precipitation was recorded as level I, slight precipitation as level II, precipitation as level III, more precipitation as level IV, and severe precipitation as level V.

[0105] The test results are shown in Table 2:

[0106] Table 2 Test Results of Flame Retardant and Mechanical Properties

[0107]

[0108]

[0109] According to Table 2, and in conjunction with Example 1, Comparative Example 1, and Comparative Example 2, it can be seen that the flame retardant rating of Comparative Example 1 and Comparative Example 2 is FV-1, with no dripping flammability. The tensile strength is lower than that of Example 1, and there is slight precipitation, indicating that the flame retardant performance of Comparative Example 1 and Comparative Example 2 is lower than that of Example 1, and their mechanical properties are also lower. This may be because the amount of epoxy resin-SiO2 microcapsule modified polyphosphate added in Comparative Example 1 is reduced, falling below the required range, while the amount added in Comparative Example 2 is increased, exceeding the required range. When the amount of epoxy resin-SiO2 microcapsule modified polyphosphate is reduced, the flame retardant efficiency also decreases, and the crosslinking density between the epoxy resin-SiO2 microcapsule modified polyphosphate and the silane-modified polyether also decreases, resulting in lower mechanical properties of the flame-retardant sealant. When the amount of epoxy resin-SiO2 microcapsule modified polyphosphate is increased, it is prone to agglomeration, and excessive addition of flame retardant will reduce the mechanical properties of the flame-retardant sealant.

[0110] Combining Example 1 and Comparative Example 3, it can be seen that the flame retardancy rating of Comparative Example 3 is FV-2. When dripping onto cotton, the tensile strength is significantly lower than that of Example 1, and there is more exudation. This indicates that the flame retardancy of Comparative Example 3 is significantly lower than that of Example 1, and its migration resistance and mechanical properties are significantly reduced. The reason for this may be that the ammonium polyphosphate in Comparative Example 3 was only modified with silica microcapsules. On the one hand, the lack of epoxy resin results in poor compatibility between ammonium polyphosphate and silane-modified polyether, leading to decreased migration resistance and flame retardancy. On the other hand, it cannot crosslink with silane-modified polyether, resulting in a decrease in crosslinking density. This makes it difficult to inhibit the exudation of small molecules such as flame retardant plasticizers, leading to a decrease in density and consequently, a decline in mechanical properties.

[0111] Combining Example 1 and Comparative Example 4, it can be seen that the flame retardancy rating of Comparative Example 4 is FV-1, it does not drip, and its tensile strength is significantly lower than that of Example 1, with some precipitation. This indicates that the flame retardancy of Comparative Example 4 is lower than that of Example 1, and its migration resistance and mechanical properties are also reduced. The reason for this may be that the ammonium polyphosphate in Comparative Example 4 was only modified with epoxy resin, lacking the inorganic barrier formed by silica during combustion, thus reducing the flame retardant performance of the flame-retardant sealant.

[0112] Combining Example 1 and Comparative Example 5, it can be seen that the flame retardancy rating of Comparative Example 5 is FV-2, it drips onto cotton and ignites, and its tensile strength is significantly lower than that of Example 1, with severe exudation. This indicates that the flame retardancy of Comparative Example 5 is significantly lower than that of Example 1, and its migration resistance and mechanical properties are also significantly reduced. The reason for this may be that the ammonium polyphosphate in Comparative Example 5 was not modified. On the one hand, it has poor compatibility with silane oligomers and epoxy resins, resulting in a significant decrease in migration resistance. On the other hand, it cannot form a cross-linked structure, thus failing to inhibit the exudation of small molecule substances such as flame retardant plasticizers, leading to a significant decrease in flame retardant performance and mechanical properties.

[0113] Combining Examples 1 and 2-19, it can be seen that the flame retardant rating, tensile strength, and migration resistance of Examples 2-19 are not significantly different from those of Example 1, indicating that the flame retardant properties, mechanical properties, and migration resistance of Examples 2-19 are not significantly different from those of Example 1. This may be because Examples 2-19 only varied the proportions of the flame-retardant sealant raw materials within the required range, demonstrating that changing the raw material proportions within the required range has no significant impact on the performance of the flame-retardant sealant.

[0114] Combining Examples 1, 20, and 21, it can be seen that Examples 20 and 21 show a slight decrease in mechanical properties and slight precipitation compared to Example 1. This indicates that the migration resistance of Example 20 is slightly reduced. The reason may be that the SiO2 content of the epoxy resin-SiO2 microcapsule modified ammonium polyphosphate in Example 20 is reduced, the inorganic layer effect on the surface of ammonium polyphosphate is weakened, and ammonium polyphosphate shows slight precipitation.

[0115] Combining Examples 1, 22, and 23, it can be seen that the mechanical properties of Examples 22 and 23 are lower than those of Example 1, and there is slight precipitation, indicating that the mechanical properties and migration resistance of Examples 22 and 23 are lower than those of Example 1. This may be because the epoxy resin content in the epoxy resin-SiO2 microcapsule modified ammonium polyphosphate is reduced in Example 22, while it is increased in Example 23. The reduction in epoxy resin content leads to a decrease in crosslinking density, increasing the probability of small molecules overflowing from the surface of the flame-retardant sealant. The decrease in crosslinking density is accompanied by a decrease in the mechanical properties of the flame-retardant sealant. Furthermore, when the amount of epoxy resin added increases, the amount of epoxy resin has already reached saturation; further increasing the amount of epoxy resin does not increase the coating rate of the ammonium polyphosphate surface, and may even cause a decrease in the coating rate, thus leading to a decrease in the mechanical properties and migration resistance of the flame-retardant sealant.

[0116] Combining Examples 1, 24, and 25, it can be seen that the flame retardant rating of Example 24 decreased to FV-1 compared to Example 1. The mechanical properties of Examples 24 and 25 also decreased, indicating a decline in the flame retardant performance of Example 24. The mechanical properties of Examples 24 and 25 are also lower than those of Example 1. This may be because the amount of aluminum hydroxide added in Example 24 was reduced. Reduced filler content decreases the reinforcing effect, leading to a decrease in the mechanical properties of the flame-retardant sealant. Aluminum hydroxide also plays a synergistic role in flame retardancy, working with the flame-retardant plasticizer to increase the flame retardant performance of the sealant. A decrease in the amount of aluminum hydroxide reduces this synergistic effect, resulting in lower flame retardant performance. Conversely, when the amount of aluminum hydroxide added increases, excessive filler addition leads to a decrease in the mechanical properties of the flame-retardant sealant.

[0117] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A silane-modified two-component flame-retardant adhesive, characterized by, It includes component A and component B, wherein component A and component B comprise the following raw materials in parts by mass: Component A: 200-400 parts of silane-modified polyether; 100-200 parts of flame retardant plasticizer; Filler 1: 300-400 parts; UV absorber 3-10; Light stabilizer 3-10; Thixotropic agent 15-35 parts; 30-50 parts of silane coupling agent; 10-40 parts of the first curing agent; 10-20 parts of curing accelerator; 5-15 parts of dehydrating agent; Component B: 300-500 parts of epoxy resin; Filler 1: 250-350 parts; Filler 2: 150-250 parts; 250-350 parts of flame retardant plasticizer; Deionized water 5-15; 20-40 parts of the second curing agent; The filler 1 includes one or a combination of several of aluminum hydroxide, magnesium hydroxide, expanded graphite, borate, aluminum oxalate, and zinc sulfate; The filler 2 is epoxy resin-SiO2 microcapsule modified ammonium polyphosphate; The raw materials for the epoxy resin-SiO2 microcapsule modified ammonium polyphosphate include epoxy resin, tetraethyl orthosilicate and ammonium polyphosphate in a mass ratio of (0.1-0.3):(0.15-0.25):

1. The epoxy resin-SiO2 microcapsule modified ammonium polyphosphate was prepared according to the following method: S1. Add distilled water to the solvent, mix well, add sodium polyphosphate, dispersant and catalyst 1, stir and mix at 35-45℃ for 15-20 min, then add tetraethyl orthosilicate, react at 40-50℃ for 3-5 h, and then filter, wash and dry to obtain modified ammonium polyphosphate pre-reactant. S2. Add epoxy resin, curing agent, modified ammonium polyphosphate pre-reactant, dispersant and catalyst 2 to the solvent in sequence, stir and disperse for 20-40 min, heat the solution to 80-90℃, stir and react for 2-3 h, and after the reaction is completed, filter, wash and dry to obtain epoxy resin-SiO2 microcapsule modified ammonium polyphosphate.

2. The silane-modified two-component flame-retardant glue according to claim 1, characterized in that, The epoxy resin includes one or a combination of several of the following: polyphenolic glycidyl ether epoxy resin, aliphatic glycidyl ether epoxy resin, glycidyl ester type epoxy resin, and glycidyl amine type epoxy resin.

3. The silane-modified two-component flame retardant adhesive according to claim 1, characterized in that, The flame retardant plasticizer includes one or a combination of several of the following: tri(2-chloroethyl) phosphate, tri(2-chloropropyl) phosphate, triethyl phosphate, triphenyl phosphate, tri(1,3-dichloroisopropyl) phosphate, tributoxyethyl phosphate, and toluene diphenyl phosphate.

4. The silane-modified two-component flame retardant adhesive according to claim 1, characterized in that, The epoxy resin is a bisphenol A type epoxy resin, and the epoxy value of the epoxy resin is 0.4 to 0.

54.

5. The silane-modified two-component flame retardant adhesive according to claim 1, characterized in that, The dispersant includes one or a combination of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate; the curing agent includes one or a combination of triethylenetetramine, ethylenediamine, diethylenetriamine, tetraethylenepentamine, and m-phenylenediamine.

6. The silane-modified two-component flame retardant adhesive according to claim 5, characterized in that, The amount of dispersant added is 0.5 to 2.5% of the mass of ammonium polyphosphate, and the amount of curing agent added is 5 to 20% of the mass of epoxy resin.

7. A method for preparing a silane-modified two-component flame retardant adhesive according to any one of claims 1 to 6, characterized in that, It is prepared by the following steps: Preparation of Component A: The silane-modified polyether, flame retardant plasticizer, filler 1, ultraviolet absorber, light stabilizer and thixotropic agent are mixed and stirred at 1000-1200 rpm for 0.5-1 h under vacuum at 90-100℃. Then the mixture is cooled to 40-50℃, and the silane coupling agent, first curing agent, curing accelerator and dehydrating agent are added. After stirring evenly, Component A is obtained. Preparation of Component B: Component B is obtained by stirring and mixing epoxy resin, filler 1, filler 2, flame retardant plasticizer, deionized water and second curing agent under vacuum conditions.

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