Flame-retardant organic silicon adhesive as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of adhesives, and discloses a flame-retardant organic silicon adhesive as well as a preparation method and application thereof. According to the adhesive, 4, 4 '-(propane-2, 2-diyl) bis (2-(pent-4-ene-1-yl) cyclopentane-1-formic acid) is used as a starting raw material, and esterification, siloxane ester exchange, polymerization and other reactions are carried out, so that the organic silicon flame-retardant adhesive with good thermal stability, flame retardance and safety is obtained. The flame-retardant organic silicon adhesive prepared by the invention has a wide market prospect in manufacturing of fireproof building materials, fireproof clothes, fireproof containers, automobiles and electronic products.

Description

Technical Field

[0001] The invention relates to the technical field of flame retardant adhesives, in particular to a flame retardant organic silicon polymer adhesive and a preparation method and application thereof. Background Art

[0002] Flame retardant adhesives are adhesives that improve the material's resistance to flames and heat while maintaining its bonding properties. Such adhesives are very important in many applications that require fire safety, such as construction, transportation, electronic equipment, etc.

[0003] Silicone flame retardant adhesives are a type of synthetic resin adhesives that can maintain good bonding properties at both room and high temperatures. They usually have good bonding properties, high temperature resistance (≥200°C), low temperature resistance (-60°C), flame retardancy, electrical insulation, and wide applicability, and are non-corrosive to a variety of metals and non-metals. However, silicone adhesives have a long curing time, release volatile organic compounds, have unsatisfactory color and appearance, and have high requirements for handling and storage. Silicone is hydrophobic, and many polymer compounds are lipophilic or hydrophobic. By combining silicone with flame retardant polymer compounds, silicone can be well compatible with polymer materials, enhancing the dispersion and stability of flame retardants in materials. The prepared adhesive has synergistic flame retardancy, prevents combustion and decomposition, reduces smoke density, and has better stability, fire resistance, high and low temperature resistance, and weather resistance.

[0004] Therefore, it is particularly important to provide a flame retardant organic silicone adhesive with excellent flame retardancy, thermal stability and adhesive properties, which is green and safe. Summary of the invention

[0005] The present invention aims to provide a flame-retardant organic silicone adhesive and its preparation method and application. The adhesive uses 4,4′-(propane-2,2-diyl)bis(2-(pent-4-ene-1-yl)cyclopentane-1-carboxylic acid) as a starting material, undergoes esterification, siloxane ester exchange, polymerization and other reactions to obtain a high molecular flame-retardant polymer containing organic silicon, which has good thermal stability, flame retardancy and safety. It has broad market prospects in the manufacture of fireproof building materials, fireproof clothing, fireproof containers, automobiles and electronic products.

[0006] In order to achieve the above object, the present invention provides a flame retardant organic silicone adhesive, the structural formula of which is as follows:

[0007]

[0008] The α is an integer between 1 and 10, the β is an integer between 1 and 10, and n is an integer between 2 and 20.

[0009] The R 1Taken from any one or more of hydrogen, phosphorus, nitrogen and sulfur; the R 2 Taken from any one or more of fluorine, chlorine, bromine and iodine; said R 3 Taken from any one or more of cyano, phenyl, vinyl, and ethynyl; the R 4 It can be selected from any one or more of sulfonic acid group, ester group, carboxyl group and aldehyde group.

[0010] In order to achieve the above object, the present invention also provides a method for preparing a flame retardant organic silicone adhesive, comprising:

[0011]

[0012] Mix 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylic acid) and 3-(2-chloroethyl)tetrahydrofuran, add tetrabutylammonium bromide as a catalyst, react at 75-85° C. for 2-3 hours, and complete the reaction by TLC detection. Distill under reduced pressure for the first time to obtain bis(5-chloro-3-hydroxypentyl) 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate);

[0013] Take bis(5-chloro-3-hydroxypentyl)4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate), 2,2,4,4,6,6-hexasubstituted trioxytriazine and dichloro(vinyl)silane and dissolve them in dichloromethane, add platinum catalyst, react at room temperature for 3-5 hours, and add acid to terminate the reaction; reduce pressure and filter to obtain a solid product, wash and dry to obtain monomer A;

[0014] The monomer A and 1-substituted-3-substituted disiloxane are mixed, dissolved in tetrahydrofuran, acid is added to adjust the pH value to 4-5, a platinum catalyst is added, the reaction is carried out at 70-75°C for 6-8h, the solvent is removed by a second reduced pressure distillation, tri(pentafluorophenyl)borane is added, dissolved in dimethyl sulfoxide, and the reaction is carried out at 140-150°C for 10-12h. After the reaction is complete, an extractant, a saturated salt solution and an acid are added, the system is layered, the extractant is collected, a desiccant is added to remove water, and the extractant is removed by a third reduced pressure distillation to obtain a flame retardant organic silicone adhesive.

[0015] Preferably, the mass ratio of the 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylic acid) to 3-(2-chloroethyl)tetrahydrofuran and tetrabutylammonium bromide is 1:(0.66-0.7):(1.5-1.6).

[0016] Preferably, the first reduced pressure distillation temperature is 60-70°C.

[0017] Preferably, the mass ratio of the bis(5-chloro-3-hydroxypentyl)4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate) to 2,2,4,4,6,6-hexasubstituted trioxytriazine, chlorodimethyl(vinyl)silane, dichloromethane, and platinum catalyst is 1:(0.21-0.48):(0.4-0.92):(2.8-4):(0.048-0.156).

[0018] Preferably, the mass ratio of the monomer A to 1-substituted-3-substituted disiloxane, tetrahydrofuran, platinum catalyst, tri(pentafluorophenyl)borane and dimethyl sulfoxide is 1: (0.3-0.65): (1.8-2.8): (0.01-0.06); (0.7-1.16): (2.2-3.4).

[0019] Preferably, the temperature of the second reduced pressure distillation is 60-65°C.

[0020] Preferably, the extractant is any one or more of hexane, n-hexane, cyclohexane, petroleum ether and n-heptane.

[0021] Preferably, the saturated salt solution is any one or more of saturated sodium chloride, potassium chloride, potassium sulfate, calcium chloride and calcium sulfate.

[0022] Preferably, the desiccant is any one or more of anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous calcium silicate, and anhydrous calcium phosphate.

[0023] Preferably, the temperature of the third reduced pressure distillation is 60-85°C.

[0024] Preferably, the acid for terminating the reaction is any one or more of acetic acid, formic acid, hypochlorous acid, and oxalic acid.

[0025] Preferably, the acid used to adjust the pH is any one or more of hydrochloric acid, sulfuric acid, phosphoric acid, boric acid and nitric acid.

[0026] Preferably, the acid used for the extraction is any one or more of hydrochloric acid, sulfuric acid, trichloroacetic acid, and citric acid.

[0027] The present invention also provides the use of the flame-retardant organic silicone adhesive in the manufacture of fireproof building materials, fireproof clothing, fireproof containers, automobiles and electronic products.

[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0029] (1) The present invention uses a synthetic new compound bis(5-chloro-3-hydroxypentyl) 4,4′-(propane-2,2-diyl)bis(2-(pent-4-ene-1-yl)cyclopentane-1-carboxylate) as a monomer, carries out siloxane ester exchange with 2,2,4,4,6,6-hexasubstituted trioxytriazine and chlorodisubstituted (vinyl) silane, and further crosslinks and polymerizes with 1-substituted-3-substituted disiloxane to obtain a high molecular flame retardant adhesive containing organic silicon. Compared with traditional adhesives, the molecular structure is more complex, and different functional groups give the material better flame retardancy, thermal stability, toughness and transparency.

[0030] (2) The flame-retardant organic silicone adhesive prepared by the present invention exerts flame retardant effects from several aspects, such as energy absorption, free radical inhibition, and formation of a carbonized layer, through the synergistic effect of the functional groups of the polymer compound and the organic silicon. Organic silicon gives the material higher mechanical properties, and the polymer contains multiple chemical bonds such as CC and C=O. These bonds have a high thermal decomposition temperature and can maintain structural integrity at high temperatures, thereby extending the service life of the adhesive.

[0031] (3) The flame retardant organic silicone adhesive prepared by the present invention is polymerized from monomers modified with multiple functional groups. 1 Derived from inorganic atoms, hydrogen, phosphorus, nitrogen, and sulfur. Hydrogen and nitrogen release inert gases at high temperatures, diluting the oxygen concentration around the combustion process, thereby inhibiting combustion. Phosphorus and sulfur combine with oxygen at high temperatures to form salts with higher melting points, which help isolate oxygen and absorb heat. 2 is a halogen atom, which can catalyze the decomposition of unstable free radicals; R 3 Derived from cyano, vinyl, propylene and other functional groups with unsaturated double bonds or triple bonds and aromatic compounds such as benzene. Unsaturated double bonds and triple bonds can cross-link with other functional groups on the polymer chain at high temperatures, which can significantly improve the stability and flame retardancy of the material. Aromatic compounds are easily carbonized at high temperatures, and the carbonized layer can effectively prevent oxygen from contacting the polymer, thereby slowing down the combustion process; R 4 Functional groups containing -C=O double bonds, such as sulfonic acid group, ester group, carboxyl group, and carbonyl group, can improve the structural stability of the adhesive while reacting with the free radicals generated during the combustion process, inhibiting the chain reaction of free radicals and reducing the combustion rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is the infrared spectrum of the adhesive prepared in Example 4.

[0033] Figure 2 These are scanning electron microscope (SEM) images of the adhesives prepared in Examples 1 to 4.

[0034] Figure 3Schematic diagram of the tensile shear strength of the adhesives prepared in Examples 1 to 4 and Comparative Examples 1 to 3. DETAILED DESCRIPTION

[0035] The following embodiments are only used to more clearly illustrate the technical solutions of the present invention, and are not intended to limit the protection scope of the present invention.

[0036] Example 1

[0037] A method for preparing a flame retardant organic silicone adhesive comprises the following steps:

[0038] (1) Accurately weigh 10 g of 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylic acid), mix evenly with 6.6 g of 3-(2-chloroethyl)tetrahydrofuran, add 15 g of tetrabutylammonium bromide catalyst, and heat under reflux at 75-85° C. for 2-3 h. The reaction is complete as monitored by TLC, and the compound bis(5-chloro-3-hydroxypentyl) 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate) is obtained by distillation under reduced pressure.

[0039] (2) Accurately weigh 10 g of bis(5-chloro-3-hydroxypentyl)4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate), 2.14 g of 1,3,5,2,4,6-trioxatrisilane, and 4 g of chlorodifluoro(vinyl)silane, dissolve them in 20 mL of dichloromethane, add 0.48 g of platinum catalyst, stir at room temperature for 3 to 5 h, and add 10 mL of acetic acid to terminate the reaction; collect the solid product by vacuum filtration, wash with deionized water, and dry to obtain monomer A.

[0040] (3) Accurately weigh 10 g of monomer A and 6.5 g of 3,3-dicyanodisiloxane-1,1-disulfonic acid, dissolve them in 18 mL of tetrahydrofuran, add hydrochloric acid to adjust the pH of the system to 4-5, then add 0.2 g of platinum catalyst, react at 60-65° C. for 6-8 h, remove the solvent by reduced pressure distillation, mix the obtained oligomer with 11.6 g of tris(pentafluorophenyl)borane, dissolve in 22 mL of dimethyl sulfoxide, react at 140-150° C. for 10-12 h, and the reaction is complete. After that, the system has obvious stratification; add 30mL of n-hexane into the system, shake, wait for the substance in the system to precipitate, dissolve in n-hexane, add 20mL of saturated sodium chloride aqueous solution, and shake to promote the precipitation of the product; add 5mL of dilute sulfuric acid, wait for demulsification; wait until the system is obviously stratified, at this time the upper layer is n-hexane, and the lower layer is dimethyl sulfoxide; take the upper liquid, add 15g of anhydrous sodium sulfate to remove water in the solvent, and remove n-hexane by reduced pressure distillation at 65-70°C to obtain an organic silicone adhesive.

[0041] Example 2

[0042] A method for preparing a flame retardant organic silicone adhesive comprises the following steps:

[0043] (1) Accurately weigh 10 g of 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylic acid), mix evenly with 7 g of 3-(2-chloroethyl)tetrahydrofuran, add 16 g of tetrabutylammonium bromide as a catalyst, and react at 75-85° C. for 2-3 h. The reaction is completed as monitored by TLC, and distilled under reduced pressure to obtain the compound bis(5-chloro-3-hydroxypentyl) 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate).

[0044] (2) Accurately weigh 10 g of bis(5-chloro-3-hydroxypentyl)4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate), 4.5 g of 2,2,4,4,6,6-hexa(L1-phosphonyl)-1,3,5,2,4,6-trioxatrisilane, and 4.5 g of trichloro(vinyl)silane, dissolve them in 24 mL of dichloromethane, add 0.72 g of platinum catalyst, stir at room temperature for 3 to 5 h, and add 10 mL of acetic acid to terminate the reaction; collect the solid product by vacuum filtration, wash with deionized water, and dry to obtain monomer A.

[0045] (3) 10 g of monomer A and 5.7 g of dimethyl 3,3-diphenyldisiloxane-1,1-dicarboxylate were accurately weighed and mixed, dissolved in 22 mL of tetrahydrofuran, hydrochloric acid was added to adjust the pH of the system to 4-5, and then 0.3 g of platinum catalyst was added. The mixture was reacted at 60-65° C. for 6-8 h, and the solvent was removed by distillation under reduced pressure. The obtained oligomer was mixed with 9.6 g of tris(pentafluorophenyl)borane, dissolved in 26 mL of dimethyl sulfoxide, and reacted at 140-150° C. for 10-12 h. After completion, 30 mL of cyclohexane was added into the system, and the system had obvious stratification. Oscillation can promote the precipitation of substances in the system from dimethyl sulfoxide and dissolve them in cyclohexane. 20 mL of saturated sodium chloride aqueous solution was added to promote the precipitation of the product. 5 mL of hydrochloric acid was added and waited for demulsification. The system had obvious stratification, with cyclohexane as the upper layer and dimethyl sulfoxide as the lower layer. The upper liquid was taken and 20 g of anhydrous sodium sulfate was added to remove water from the solvent. The cyclohexane was removed by reduced pressure distillation at 70-75°C to obtain an organic silicone adhesive.

[0046] Example 3

[0047] A method for preparing a flame retardant organic silicone adhesive comprises the following steps:

[0048] (1) Accurately weigh 10 g of 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylic acid), mix evenly with 7 g of 3-(2-chloroethyl)tetrahydrofuran, add 16 g of tetrabutylammonium bromide catalyst, and react at 75-85° C. for 2-3 h. After TLC monitoring, the reaction is complete, and distillation is performed under reduced pressure to obtain the compound bis(5-chloro-3-hydroxypentyl) 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate).

[0049] (2) Accurately weigh 10 g of bis(5-chloro-3-hydroxypentyl)4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate), 3.6 g of 2,2,4,4,6,6-hexa(L1-azanaphthyl)-1,3,5,2,4,6-trioxatrisilane, and 7.7 g of dibromochloro(vinyl)silane, dissolve them in 36 mL of dichloromethane, add 0.92 g of platinum catalyst, stir at room temperature for 3 to 5 h, and then add 10 mL of acetic acid to terminate the reaction; collect the solid product by filtration under reduced pressure, wash with deionized water, and dry to obtain monomer A.

[0050] (3) Accurately weigh 10 g of monomer A and 4.2 g of 3,3-diallyldisiloxane-1,1-dicarboxylic acid, mix them, dissolve them in 24 mL of tetrahydrofuran, add hydrochloric acid to adjust the pH of the system to 4-5, then add 0.4 g of platinum catalyst, react at 60-65° C. for 6-8 h, remove the solvent by reduced pressure distillation, mix the obtained oligomer with 8.7 g of tris(pentafluorophenyl)borane, dissolve them in 28 mL of dimethyl sulfoxide, react at 140-150° C. for 10-12 h, and the reaction is complete. Then, 40 mL of petroleum ether was added into the system, and the system had obvious stratification. Oscillation promoted the precipitation of substances in the system from dimethyl sulfoxide and transferred them into petroleum ether. 20 mL of saturated calcium chloride aqueous solution was added to promote the precipitation of the product. 5 mL of hydrochloric acid was added and waited for demulsification. The system had obvious stratification, with the upper layer being petroleum ether and the lower layer being dimethyl sulfoxide. The upper liquid was taken and 20 g of anhydrous sodium sulfate was added to remove a small amount of water in the solvent. The petroleum ether was removed by reduced pressure distillation at 60-65° C. to obtain an organic silicone adhesive.

[0051] Example 4

[0052] A method for preparing a flame retardant organic silicone adhesive comprises the following steps:

[0053] (1) Accurately weigh 10 g of 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylic acid), mix evenly with 6.6 g of 3-(2-chloroethyl)tetrahydrofuran, add 15 g of tetrabutylammonium bromide catalyst, and heat under reflux at 75-85° C. for 2-3 h. The reaction is complete when monitored by TLC, and the mixture is concentrated by distillation under reduced pressure to obtain pure bis(5-chloro-3-hydroxypentyl) 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate).

[0054] (2) Accurately weigh 10 g of bis(5-chloro-3-hydroxypentyl)4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate), 4.5 g of 2,2,4,4,6,6-hexa(L1-sulfonamido)-1,3,5,2,4,6-trioxatrisilane, and 9.2 g of chlorodiiodo(vinyl)silane, mix well, add 40 mL of dichloromethane to dissolve, add 1.5 g of platinum catalyst, stir at room temperature for 3 to 5 h, and then add 10 mL of acetic acid to terminate the reaction; filter under reduced pressure to obtain a solid product, wash with deionized water, and dry to obtain pure monomer b.

[0055] (3) 10 g of monomer A and 3 g of 3,3-di(prop-2-yn-1-yl)disiloxane-1,1-dicarbaldehyde were accurately weighed and dissolved in 30 mL of tetrahydrofuran. The pH of the system was adjusted to 4-5 with hydrochloric acid. 0.4 g of platinum catalyst was added. The mixture was heated to reflux at 60-65° C. for 6-8 h. The solvent was removed by distillation under reduced pressure. The obtained oligomer was mixed with 7.1 g of tris(pentafluorophenyl)borane, dissolved in 30 mL of dimethyl sulfoxide, and heated to reflux at 140-150° C. for 10-12 h. After the reaction is complete, 30 mL of n-hexane is added to the system, and the substance in the system is shaken to promote the precipitation of the substance from the dimethyl sulfoxide, and dissolved in n-hexane, and 20 mL of saturated sodium chloride aqueous solution is added, and the product is shaken to promote the precipitation; 5 mL of sulfuric acid is added, and wait for demulsification; wait until the system is obviously stratified, at this time the upper layer is n-hexane and the lower layer is dimethyl sulfoxide; take the upper liquid, add 15 g of anhydrous sodium sulfate to remove the moisture in the solvent, and remove the n-hexane by reduced pressure distillation at 65-70°C to obtain an organic silicone adhesive.

[0056] Comparative Example 1

[0057] A method for preparing a flame-retardant organic silicone adhesive, which is different from that of Example 3 in that in step (2), 2,2,4,4,6,6-hexa(L1-azanaphthyl)-1,3,5,2,4,6-trioxatrisilane is replaced by 2,2,4.4.6,6-hexamethyl-1,3,5,2,4,6-trioxatrisilane, and dibromochloro(vinyl)silane is replaced by chlorodiethyl(vinyl)silane; in step (3), 3,3-diallyldisiloxane-1,1-dicarboxylic acid is replaced by 1,1-di-tert-butyl-3,3-diisopropyldisiloxane.

[0058] Comparative Example 2

[0059] A method for preparing a flame-retardant organic silicone adhesive, which is different from that of Example 3 in that 3,3-diallyldisiloxane-1,1-dicarboxylic acid in step (3) is replaced by 1,1-diethyl-3,3-dimethyldisiloxane.

[0060] Comparative Example 3

[0061] A method for preparing a flame-retardant organic silicone adhesive, which is different from that of Example 3 in that 3,3-diallyldisiloxane-1,1-dicarboxylic acid in step (3) is replaced by 1,1-di-tert-butyl-3,3-diisopropyldisiloxane.

[0062] Structural characterization: The structure of the prepared organic silicone adhesive was characterized by infrared (IR). Figure 1 According to the infrared spectrum shown, the organic silicone adhesive prepared in Example 3 has a deformation vibration of the silane group at 431 μm; there is an absorption peak of bending vibration and out-of-plane swing of the -CH bond in alkanes and olefins and deformation vibration of the -CO bond at 552-681 μm; the compression vibration of the Si-N bond and the symmetric vibration of silicon and bromine atoms are at 844 μm; the stretching vibration of the Si-N bond and the bending vibration of the -Si-O-Si bond are at 948 μm; the absorption peak at 1130 μm belongs to the deformation vibration of the -C=O bond on the carbonyl and carboxyl groups. 1257μm is the absorption peak of -CN- bond; 1296μm and 1349μm are the stretching vibration of -CO- single bond on carboxyl and carbonyl groups; 1460μm and 1640μm are the stretching vibration peaks of -CC- single bond and -C=C- double bond; 2910μm is the stretching vibration of CH bond of saturated olefin and unsaturated olefin; 3444μm is the stretching vibration of -OH bond.

[0063] according to Figure 2 As shown in the SEM images of the flame-retardant organic silicone adhesives prepared in Examples 1 to 4 and Comparative Examples 1 to 3, Examples 1 to 4 show good morphology and stability, and the adhesive prepared in Example 3 has the smoothest and densest internal molecular structure, the highest degree of polymer cross-linking, and good thermal stability and mechanical strength.

[0064] Adhesive performance characterization: The prepared samples were tested according to the test methods specified in GB / T 7124 and GB / T 3512. Figure 3 As shown, the bonding performance of Examples 1 to 4 to metal, wood, artificial board, glass and ceramics is stronger than that of Comparative Examples 1 to 3. This is because the main chain of monomer A is modified by alkyl in Comparative Examples 1 to 3, and alkyl is a non-polar electron-withdrawing group, which is easy to conjugate with adjacent π electrons, resulting in electron delocalization, weakening the interaction between molecules, and thus affecting the bonding performance. The main chain of the monomers in Comparative Example 1 is modified by alkyl, and the adhesion to several samples is poor, especially for relatively smooth glass and ceramic objects, the tensile shear strength is reduced by 80.03% and 82.61%.

[0065] Thermal stability test: The thermal stability of the sample was tested using a TG 209 thermogravimetric analyzer under nitrogen protection. 3-5 mg of the sample was weighed in an alumina crucible, and the temperature was raised at a programmed rate of 10°C / min to test the initial decomposition temperature, maximum decomposition temperature, and residual weight of the sample at 800°C.

[0066] Table 1 Adhesive thermal stability parameters

[0067]

[0068]

[0069] According to the data in Table 1, the initial decomposition temperature and the maximum decomposition temperature of the adhesive prepared by Examples 1 to 4 are higher than those of Comparative Examples 1 to 3. The residual weight of the adhesive of Examples 1 to 4 after burning at 800°C is also higher than that of Comparative Examples 1 to 3. The experimental results show that the adhesive prepared by the examples has stronger thermal stability, which is due to the modification of its main chain functional groups. The thermal stability of Example 3 is the most outstanding, with an initial decomposition temperature of 289.5°C, a maximum decomposition temperature of 513.6°C, and a residual weight of more than 55% at 800°C. Its main chain structure uses nitrogen, bromine, vinyl and carboxyl functional groups. The lone pair of electrons of the nitrogen atom can form a covalent bond with a metal or non-metal, thereby improving the thermal stability of the polymer. The double bond of the vinyl group can form a cross-linked network with other functional groups, thereby improving the stability of the material. The comparative examples all use non-polar electron-donating alkyl groups to modify the main chain, reduce the electron density of adjacent functional groups, and lead to uneven charge distribution inside the molecule. At the same time, the entropy of the polymer is increased, making the molecular chain easier to loosen and the stability is reduced.

[0070] Mechanical properties test: The tensile strength and elongation at break of the test samples were tested using a UTM 4204 electronic universal testing machine. Dumbbell-shaped specimens were cut using a standard mold and stretched at a rate of 50 mm / min. Three test specimens were selected for each group of samples and the average value was taken. The higher the tensile strength and the lower the elongation at break, the better the tensile properties of the sample.

[0071] Table 2 Mechanical properties of adhesives

[0072]

[0073] According to the data in Table 2, the tensile strength of Examples 1 to 4 is higher than that of Comparative Examples 1 to 3, and the elongation at break is lower than that of Comparative Examples 1 to 3. The experimental results show that the functional groups used to modify the main chain of the adhesive in Examples 1 to 4 can improve its mechanical strength, and the alkyl-modified molecular chains used in Comparative Examples 1 to 3 are relatively flexible, and the van der Waals forces between molecules are relatively weak, which makes it easy to slide within or between chains, reducing the mechanical strength, stiffness, tear strength and wear resistance of the polymer.

[0074] Flame retardant performance test: The prepared samples were tested according to the test methods specified in GB / T 5169.10-2014 and GB / T 20284-2006.

[0075] Table 3 Adhesive flame retardant performance parameters

[0076]

[0077] According to the data in Table 3: after 10 combustions of not less than 30 seconds, the total flaming combustion time, the total flameless combustion time, the maximum single flaming combustion time and the flameless combustion time of the adhesive prepared in Examples 1 to 4 are significantly lower than those in Comparative Examples 1 to 3. The flame retardant performance of the adhesive prepared in Example 3 is significantly stronger than that of the other groups. The nitrogen element in its main chain releases inert gas at high temperature, isolates oxygen, and thus inhibits combustion. The catalytic effect of bromine atoms can decompose the unstable free radicals generated during combustion. The vinyl and carboxyl groups can form strong interactions through hydrogen bonds or with other functional groups, thereby reducing the number of free radicals in the polymer and inhibiting the chain combustion reaction. In the comparative example, the alkyl group is easily attacked by free radicals and photochemical oxidants, and oxidation easily destroys the structure of the alkyl molecule, reducing its stability, thereby reducing its flame retardant performance.

[0078] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A flame retardant organic silicone adhesive, characterized in that: Its structure is as follows: In the structure, α is an integer between 1 and 10, β is an integer between 1 and 10, and n is an integer between 2 and 20; R1 is any one or more of hydrogen, phosphorus, nitrogen, and sulfur; R2 is any one or more of fluorine, chlorine, bromine, and iodine; R3 is any one or more of cyano, phenyl, vinyl, and acetylene; R4 is any one or more of sulfonic acid, ester, carboxyl, and aldehyde.

2. The method for preparing a flame retardant organic silicone adhesive according to claim 1, characterized in that: include: Mix 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylic acid) and 3-(2-chloroethyl)tetrahydrofuran, add tetrabutylammonium bromide as a catalyst, react at 75-85° C. for 2-3 hours, and complete the reaction by TLC detection. Distill under reduced pressure for the first time to obtain bis(5-chloro-3-hydroxypentyl) 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate); Take bis(5-chloro-3-hydroxypentyl)4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate), 2,2,4,4,6,6-hexasubstituted trioxytriazine and dichloro(vinyl)silane and dissolve them in dichloromethane, add platinum catalyst, react at room temperature for 3-5 hours, and add acid to terminate the reaction; reduce pressure and filter to obtain a solid product, wash and dry to obtain monomer A; The monomer A and 1-substituted-3-substituted disiloxane are mixed, dissolved in tetrahydrofuran, acid is added to adjust the pH value to 4-5, a platinum catalyst is added, the reaction is carried out at 70-75°C for 6-8h, the solvent is removed by a second reduced pressure distillation, tri(pentafluorophenyl)borane is added, dissolved in dimethyl sulfoxide, and the reaction is carried out at 140-150°C for 10-12h. After the reaction is complete, an extractant, a saturated salt solution and an acid are added, the system is layered, the extractant is collected, a desiccant is added to remove water, and the extractant is removed by a third reduced pressure distillation to obtain a flame retardant organic silicone adhesive.

3. The method for preparing a flame retardant organic silicone adhesive according to claim 2, characterized in that: The mass ratio of the 4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylic acid) to 3-(2-chloroethyl)tetrahydrofuran and tetrabutylammonium bromide is 1:(0.66-0.7):(1.5-1.6); the first reduced pressure distillation temperature is 60-70°C.

4. The method for preparing a flame retardant organic silicone adhesive according to claim 2, characterized in that: The mass ratio of the bis(5-chloro-3-hydroxypentyl)4,4′-(propane-2,2-diyl)bis(2-(pent-4-en-1-yl)cyclopentane-1-carboxylate) to 2,2,4,4,6,6-hexasubstituted trioxytriazine, chlorodimethyl(vinyl)silane, dichloromethane, and platinum catalyst is 1:(0.21-0.48):(0.4-0.92):(2.8-4):(0.048-0.156).

5. The method for preparing a flame retardant organic silicone adhesive according to claim 2, characterized in that: The mass ratio of the monomer A to 1-substituted-3-substituted disiloxane, tetrahydrofuran, platinum catalyst, tri(pentafluorophenyl)borane and dimethyl sulfoxide is 1: (0.3-0.65): (1.8-2.8): (0.01-0.06); (0.7-1.16): (2.2-3.4); the temperature of the second reduced pressure distillation is 60-65°C.

6. The method for preparing a flame retardant organic silicone adhesive according to claim 2, characterized in that: The extractant is any one or more of hexane, n-hexane, cyclohexane, petroleum ether and n-heptane.

7. The method for preparing a flame retardant organic silicone adhesive according to claim 2, characterized in that: The saturated salt solution is any one or more of sodium chloride, potassium chloride, potassium sulfate, calcium chloride, and calcium sulfate; the desiccant is any one or more of anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous calcium silicate, and anhydrous calcium phosphate; the temperature of the third reduced pressure distillation is 60-85°C.

8. The method for preparing a flame retardant organic silicone adhesive according to claim 2, characterized in that: The acid used for the termination reaction is any one or more of acetic acid, formic acid, hypochlorous acid, and oxalic acid; the acid used for adjusting the pH is any one or more of hydrochloric acid, sulfuric acid, phosphoric acid, boric acid, and nitric acid; the acid used for the extraction is any one or more of hydrochloric acid, sulfuric acid, trichloroacetic acid, and citric acid.

9. Use of the flame-retardant organic silicone adhesive according to claim 1 in the manufacture of fireproof building materials, fireproof clothing, fireproof containers, automobiles and electronic products.

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