Reactive phosphorus-containing organosilicon macromolecular flame retardant, and preparation method and application thereof

Abstract

The invention discloses a reaction type phosphorus-containing organic silicon macromolecular flame retardant and a preparation method and application thereof.The preparation method comprises the steps that two intermediates with alkenyl, namely an alkenyl functionalized symmetrical phosphorus-containing monomer and alkenyl POSS, are prepared respectively, and then through the copolymerization reaction between the two kinds of alkenyl, the flame retardant is obtained; a phosphorus-based flame-retardant element and a silicon-based flame-retardant element are chemically bonded to the same macromolecular chain, so that the reaction type phosphorus-containing organic silicon macromolecular flame retardant is obtained. When the flame retardant is applied to a layer-adding adhesive film, the common technical problem that the brittleness of the adhesive film is large due to the fact that a traditional small-molecule flame retardant is poor in thermal stability, easy to migrate and poor in compatibility with a polymer matrix can be solved; through the synergistic effect of the flame retardant and other components, the flame-retardant efficiency of the layer-adding adhesive film is further improved, the small dosage of the flame retardant and the high performance of the flame-retardant material are realized, and good dielectric properties are obtained.

Description

Technical Field

[0001] This invention relates to the field of flame retardant materials technology, and in particular to a reactive phosphorus-containing organosilicon macromolecular flame retardant, its preparation method and application. Background Technology

[0002] The combustion process of polymer materials is a complex multiphase reactive process, involving both physical and chemical changes. Reactive flame retardants exhibit different flame-retardant mechanisms in different flame-retardant systems due to differences in their composition and the material properties of different polymers. Generally, the flame-retardant mechanisms of reactive flame retardants can be classified into two categories: gas-phase mechanisms and condensation-phase mechanisms. The main function of reactive flame retardants in flame-retardant materials is to generate non-combustible gases during polymer combustion, dilute the concentration of combustible gases, effectively reduce the thermal effect of the material during combustion and decomposition, increase the amount of charring, and hinder the transfer of oxygen and heat. In addition, some polymer materials, after treatment with reactive flame retardants, show a significant increase in their ignition temperature, thus achieving a flame-retardant effect.

[0003] The flame-retardant properties of laminated films are indispensable for the practical application of products, especially for flip-chip ball grid array (FC-BGA) packaging substrates, which require films that can be used at high temperatures and have good flame-retardant properties. Currently, the key technical challenges of flame-retardant films are mainly: First, most currently used flame retardants are small-molecule additives, but these flame retardants have poor thermal stability, are prone to migration, and have poor compatibility with resins, easily leading to brittleness and cracking of the film; this is not conducive to obtaining film materials with good flame-retardant and dielectric properties. Second, halogenated flame retardants are often used, but they decompose upon heating, releasing corrosive and toxic gases such as hydrogen halides, posing environmental and safety concerns. Third, since the film is a thin-walled product, a large amount of flame retardant is needed to achieve the desired flame-retardant rating, which degrades the performance of the resin matrix and significantly increases costs.

[0004] Therefore, existing technologies still need improvement and development. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a reactive phosphorus-containing organosilicon macromolecular flame retardant, its preparation method and application, aiming to improve the flame retardant efficiency of the flame retardant for the laminated film.

[0006] The technical solution of the present invention is as follows: In a first aspect, the present invention provides a method for preparing a reactive phosphorus-containing organosilicon macromolecular flame retardant, comprising the following steps: S1. Provide a symmetrical phosphorus-containing monomer, and react the symmetrical phosphorus-containing monomer with 4-vinylbenzyl chloride to obtain an alkenyl-functionalized symmetrical phosphorus-containing monomer; S2. 3-Aminopropyltrimethoxysilane is reacted with an acid catalyst to obtain ammonium salt amino POSS; the ammonium salt amino POSS is reacted with a base by heating to obtain free amino POSS; the free amino POSS is mixed with triethylamine and allyl chloride and heated under reflux to obtain alkenyl POSS; S3. Mix the alkenyl-functionalized symmetrical phosphorus-containing monomer and the alkenyl POSS and carry out a polymerization reaction to obtain the reactive phosphorus-containing organosilicon macromolecular flame retardant. The structural formula of the symmetrical phosphorus-containing monomer is: .

[0007] Optionally, in step S1, providing the symmetrical phosphorus-containing monomer specifically includes: reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with terephthalaldehyde to obtain the symmetrical phosphorus-containing monomer.

[0008] Optionally, in step S1, the mass ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to terephthalaldehyde is 1:0.2~0.4; and / or, the mass ratio of the symmetrical phosphorus-containing monomer to 4-vinylbenzyl chloride is 1:0.3~1.2.

[0009] Optionally, in step S2, the acid catalyst is at least one selected from trifluoromethanesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, hydrochloric acid, nitric acid, and trifluoroacetic acid.

[0010] Optionally, in step S2, the alkali is at least one selected from sodium methoxide, sodium hydroxide, potassium hydroxide, and sodium ethoxide.

[0011] Optionally, in step S2, the mass ratio of 3-aminopropyltrimethoxysilane to the acid catalyst is 1:1.0~1.5; and / or, the mass ratio of the ammonium salt amino POSS to the base is 1:0.5~1; and / or, the mass ratio of the free amino POSS to triethylamine and allyl chloride is 1:0.8~1.0:0.5~0.8.

[0012] Optionally, in step S3, the mass ratio of the alkenyl-functionalized symmetrical phosphorus-containing monomer to the alkenyl POSS is 1:0.2~0.5.

[0013] Optionally, in step S3, the polymerization reaction of mixing the alkenyl-functionalized symmetrical phosphorus-containing monomer and the alkenyl POSS specifically includes: adding the alkenyl-functionalized symmetrical phosphorus-containing monomer, alkenyl POSS and azobisisobutyronitrile to a solvent, and heating to 60~80℃ under a nitrogen atmosphere for 6~8h for polymerization reaction.

[0014] In a second aspect, the present invention provides a reactive phosphorus-containing organosilicon macromolecular flame retardant, wherein the reactive phosphorus-containing organosilicon macromolecular flame retardant is prepared by the above-described preparation method.

[0015] In a third aspect, the present invention provides the application of a reactive phosphorus-containing organosilicon macromolecular flame retardant in a laminated film, wherein the reactive phosphorus-containing organosilicon macromolecular flame retardant is prepared by the above-described preparation method.

[0016] Beneficial effects: This invention provides a reactive phosphorus-containing organosilicon macromolecular flame retardant, its preparation method, and its application. Compared with the prior art, the advantages of this invention are: (1) The reactive phosphorus-containing organosilicon macromolecular flame retardant provided by the present invention contains phosphorus-containing groups introduced by alkenyl functionalized symmetrical phosphorus-containing monomers and Si-O-Si cage-like skeletons introduced by alkenyl POSS; wherein, in the early stage of combustion, the phosphorus-containing groups decompose to generate phosphoric acid to catalyze the dehydration and cross-linking reaction of epoxy resin, and rapidly form an expanded and dense porous carbon layer. At the same time, the Si-O-Si cage-like skeleton migrates to the surface of the carbon layer and combines with the carbon layer formed by phosphorus catalysis to form a more stable, stronger, and more heat-insulating and material-insulating glassy protective layer, which effectively blocks the diffusion of internal combustible gases to the outside and the penetration of external oxygen to the inside, realizing condensed phase flame retardancy, thereby effectively improving the flame retardant performance of the film material.

[0017] (2) The three-dimensional symmetrical distribution of alkenyl POSS in the reactive phosphorus-containing organosilicon macromolecular flame retardant provided by the present invention reduces the overall dipole moment and is not easily polarized in the external electric field, which significantly reduces orientation polarization loss. At the same time, the symmetrical structure of alkenyl functionalized symmetrical phosphorus-containing monomers makes the centers of positive and negative charges coincide, reduces local electric field distortion, inhibits charge migration and interface polarization, thereby effectively reducing the dielectric loss tangent of the film. Detailed Implementation

[0018] This invention provides a reactive phosphorus-containing organosilicon macromolecular flame retardant, its preparation method, and its application. To facilitate understanding of this invention, the following examples are provided. Those skilled in the art should understand that these examples are merely illustrative and should not be considered as specific limitations of the invention. Unless otherwise specified, conditions in the examples are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0019] This invention provides a method for preparing a reactive phosphorus-containing organosilicon macromolecular flame retardant, comprising the following steps: S1. Provide a symmetrical phosphorus-containing monomer, and react the symmetrical phosphorus-containing monomer with 4-vinylbenzyl chloride to obtain an alkenyl-functionalized symmetrical phosphorus-containing monomer; S2. 3-Aminopropyltrimethoxysilane is reacted with an acid catalyst to obtain ammonium salt amino POSS; the ammonium salt amino POSS is reacted with a base by heating to obtain free amino POSS; the free amino POSS is mixed with triethylamine and allyl chloride and heated under reflux to obtain alkenyl POSS; S3. Mix the alkenyl-functionalized symmetrical phosphorus-containing monomer and the alkenyl POSS and carry out a polymerization reaction to obtain the reactive phosphorus-containing organosilicon macromolecular flame retardant. The structural formula of the symmetrical phosphorus-containing monomer is: .

[0020] This invention prepares two alkenyl-containing intermediates, alkenyl-functionalized symmetrical phosphorus-containing monomers and alkenyl POSS, respectively. Then, through a copolymerization reaction between these two alkenyl groups, phosphorus-based and silicon-based flame-retardant elements are chemically bonded to the same macromolecular chain, resulting in a reactive phosphorus-containing organosilicon macromolecular flame retardant. This reactive phosphorus-containing organosilicon macromolecular flame retardant comprises phosphorus-containing groups introduced by the alkenyl-functionalized symmetrical phosphorus-containing monomer and a Si-O-Si cage-like framework introduced by the alkenyl POSS. Through the structures of the alkenyl POSS and the alkenyl-functionalized symmetrical phosphorus-containing monomer, and their synergistic effect, the dielectric loss tangent of the laminated film can be effectively reduced. Furthermore, during combustion, the phosphorus-containing groups in the reactive phosphorus-containing organosilicon macromolecular flame retardant rapidly form a porous char layer, while the Si-O-Si cage-like framework of the POSS forms a stable glassy protective layer on the char layer surface. The synergistic effect of these two components significantly enhances the condensed phase flame-retardant effect and improves the overall flame-retardant performance of the laminated film.

[0021] In some embodiments, step S1, providing a symmetrical phosphorus-containing monomer specifically includes: reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with terephthalaldehyde to obtain a symmetrical phosphorus-containing monomer; In some embodiments, in step S1, the mass ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to terephthalaldehyde is 1:0.2 to 0.4 (e.g., 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, etc.); and / or, the mass ratio of the symmetrical phosphorus-containing monomer to 4-vinylbenzyl chloride is 1:0.3 to 1.2 (e.g., 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1.0, 1:1.1, 1:1.2, etc.).

[0022] In the preparation of symmetrical phosphorus-containing monomers, if too little terephthalaldehyde is used, a large number of monosubstituted byproducts will be generated, leading to a decrease in the purity of the symmetrical phosphorus-containing monomers; if too much terephthalaldehyde is used, it will be difficult to completely remove it after the reaction, and the residual aldehyde group may cause side reactions in subsequent processing.

[0023] In the preparation of alkenyl-functionalized symmetrical phosphorus-containing monomers, if the amount of 4-vinylbenzyl chloride is too small, only some sites will undergo alkylation, generating monosubstituted byproducts and reducing the yield of the target dienyl product. If the amount of 4-vinylbenzyl chloride is too large, it is difficult to completely remove 4-vinylbenzyl chloride, which may remain in the final product. At the same time, the residual benzyl chloride group has high reactivity and is prone to causing side reactions.

[0024] Preferably, in step S1, the reaction of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and terephthalaldehyde to obtain a symmetrical phosphorus-containing monomer specifically includes: adding 6-8 parts by weight of terephthalaldehyde and 20-24 parts by weight of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to 150-200 parts by weight of N,N-dimethylformamide, heating to 100-110°C and stirring for 8-10 hours under a nitrogen atmosphere, distilling under reduced pressure after the reaction is completed, washing successively with anhydrous ethanol and deionized water, and drying under vacuum to obtain a symmetrical phosphorus-containing monomer.

[0025] Preferably, in step S1, the symmetrical phosphorus-containing monomer and 4-vinylbenzyl chloride are reacted to obtain an alkenyl-functionalized symmetrical phosphorus-containing monomer. Specifically, this includes: adding 10-20 parts by weight of the symmetrical phosphorus-containing monomer and 30-60 parts by weight of potassium carbonate to 200-250 parts by weight of dimethyl sulfoxide, placing the mixture under a nitrogen atmosphere, stirring at 60-70°C for 50-60 min, cooling to 10-15°C, adding 6-12 parts by weight of 4-vinylbenzyl chloride, and then stirring the mixture at 50-60°C for 6-8 h. The mixture is then filtered to obtain a filtrate, which is dried, washed with water, and recrystallized to obtain the alkenyl-functionalized symmetrical phosphorus-containing monomer.

[0026] In some embodiments, in step S2, the acid catalyst is at least one selected from trifluoromethanesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, hydrochloric acid, nitric acid, and trifluoroacetic acid. Preferably, the acid catalyst is trifluoromethanesulfonic acid.

[0027] In this embodiment, the acid catalyst can promote the hydrolysis-condensation reaction of 3-aminopropyltrimethoxysilane, promoting the formation of the POSS cage-like framework; it can also provide a moderately acidic environment, which can improve the reaction rate and product yield, and help to obtain ammonium salt amine POSS with complete structure and low impurity content.

[0028] In some embodiments, in step S2, the alkali is at least one selected from sodium methoxide, sodium hydroxide, potassium hydroxide, and sodium ethoxide. Preferably, the alkali is sodium methoxide.

[0029] In this embodiment, the base can cause the ammonium salt amine POSS to undergo a deprotonation reaction, converting the ammonium salt form into a free amine group, thus obtaining free amine POSS.

[0030] In some embodiments, in step S2, the mass ratio of 3-aminopropyltrimethoxysilane to the acid catalyst is 1:1.0~1.5 (e.g., 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, etc.); and / or, the mass ratio of the ammonium salt amino POSS to the base is 1:0.5~1 (e.g., 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, etc.); and / or, the mass ratio of the free amino POSS to triethylamine and allyl chloride is 1:0.8~1.0:0.5~0.8.

[0031] This invention uses POSS containing free amine groups as a starting material and carries out a nucleophilic substitution reaction with allyl chloride. Triethylamine is added as an acid-binding agent to neutralize the HCl generated in the reaction. By controlling the mass ratio of the three, the efficient preparation of alkenyl POSS is ensured while avoiding the generation of a large number of by-products.

[0032] Preferably, in step S2, the reaction of 3-aminopropyltrimethoxysilane with an acid catalyst to obtain ammonium salt amino POSS specifically includes: mixing and stirring 1.6-1.8 parts by weight of 3-aminopropyltrimethoxysilane, 2.2-2.4 parts by weight of trifluoromethanesulfonic acid and 30-40 parts by weight of deionized water for 120-140 min, drying to obtain a crude product, washing with acetone, and vacuum drying to obtain ammonium salt amino POSS.

[0033] Preferably, in step S2, the ammonium salt amino POSS and the base are heated to react and obtain free amino POSS. Specifically, this includes: adding 4-6 parts by weight of the ammonium salt amino POSS to 40-60 parts by weight of anhydrous ethanol, then adding 3.2-3.6 parts by weight of sodium methoxide, heating to 60-70°C for 100-120 min, distilling under reduced pressure, washing with ethyl acetate, and drying under vacuum to obtain free amino POSS.

[0034] Preferably, the step of mixing the free amino POSS with triethylamine and allyl chloride and heating under reflux to obtain alkenyl POSS specifically includes: adding 1.9-2.1 parts by weight of free amino POSS to 40-50 parts of n-propanol, then adding 1.7-1.9 parts of triethylamine and 1.2-1.4 parts of allyl chloride, heating under reflux at 70-80°C for 4-6 hours, followed by vacuum distillation and drying to obtain alkenyl POSS.

[0035] In some embodiments, in step S3, the mass ratio of the alkenyl-functionalized symmetrical phosphorus-containing monomer to the alkenyl POSS is 1:0.2~0.5.

[0036] In this embodiment, if the amount of alkenyl POSS is too small, an effective nanocomposite structure cannot be formed, making it difficult to form a continuous and robust silicate protective layer, and the effect of reducing orientation polarization loss will be worse. If the amount of alkenyl POSS is too large, alkenyl POSS has a strong tendency to self-aggregate, and strong physical aggregation will occur between POSS cages, making it impossible to prepare and form smoothly.

[0037] In some embodiments, step S3, specifically the polymerization reaction of mixing the alkenyl-functionalized symmetrical phosphorus-containing monomer and the alkenyl POSS, includes: adding the alkenyl-functionalized symmetrical phosphorus-containing monomer, alkenyl POSS and azobisisobutyronitrile to a solvent, and heating to 60-80°C under a nitrogen atmosphere for 6-8 hours.

[0038] This invention provides a reactive phosphorus-containing organosilicon macromolecular flame retardant, which is prepared by the above-described preparation method.

[0039] This invention provides an application of a reactive phosphorus-containing organosilicon macromolecular flame retardant in a laminated film, wherein the reactive phosphorus-containing organosilicon macromolecular flame retardant is prepared by the above-described preparation method.

[0040] The reactive phosphorus-containing organosilicon macromolecular flame retardant provided by this invention can solve the common technical problems of poor thermal stability, easy migration, and poor compatibility with polymer matrix of traditional small molecule flame retardants, which lead to high brittleness of the film. Through the synergistic effect of the flame retardant and other components, the flame retardant efficiency of the laminated film is further improved, realizing the small dosage of flame retardant and the high performance of flame retardant material, and obtaining good dielectric properties.

[0041] In the following embodiments, some of the raw materials are sourced from the following sources: 9,10-Dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), CAS No. 35948-25-5, purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Terephthalaldehyde, CAS No. 623-27-8, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. 4-Vinylbenzyl chloride, CAS No. 1592-20-7, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. 3-Aminopropyltrimethoxysilane, CAS No. 13822-56-5, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. Trifluoromethanesulfonic acid, CAS No. 1493-13-6, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Sodium methoxide, CAS No. 124-41-4, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Triethylamine, CAS No. 121-44-8, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Allyl chloride, CAS No. 107-05-1, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Naphthalene-type epoxy resin, model ESN-475V, purchased from Nippon Steel Chemical Materials Co., Ltd. Silica, type SO-C2, purchased from Yaduma Company; Active ester, model HPC-8150-60T, purchased from DIC Company; 1-Benzyl-2-phenylimidazole (1B2PZ), CAS No. 37734-89-7, was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0042] The present invention will be further described below through specific embodiments.

[0043] Example 1 This embodiment provides a reactive phosphorus-containing organosilicon macromolecular flame retardant and its preparation method, including the following steps: S1. By weight, 8 parts of terephthalaldehyde and 24 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were added to 200 parts of N,N-dimethylformamide. The mixture was heated to 110°C and stirred for 8 hours under a nitrogen atmosphere. After the reaction was completed, the mixture was distilled under reduced pressure, washed successively with anhydrous ethanol and deionized water, and dried under vacuum to obtain a symmetrical phosphorus-containing monomer. 20 parts of the symmetrical phosphorus-containing monomer and 60 parts of potassium carbonate were added to 250 parts of dimethyl sulfoxide. The mixture was placed under a nitrogen atmosphere and stirred at 70°C for 50 minutes. After cooling to 15°C, 12 parts of 4-vinylbenzyl chloride were added, and the mixture was stirred at 60°C for 6 hours. The mixture was filtered to obtain a filtrate, which was dried, washed with water, and recrystallized to obtain an alkenyl-functionalized symmetrical phosphorus-containing monomer. S2. By weight, 1.8 parts of 3-aminopropyltrimethoxysilane, 2.4 parts of trifluoromethanesulfonic acid, and 40 parts of deionized water were mixed and stirred for 140 min, dried to obtain a crude product, washed with acetone, and dried under vacuum to obtain ammonium salt amino POSS; 6 parts of the ammonium salt amino POSS were added to 60 parts of anhydrous ethanol, and then 3.6 parts of sodium methoxide were added, heated to 70°C for 100 min, distilled under reduced pressure, washed with ethyl acetate, and dried under vacuum to obtain free amino POSS; 2.1 parts of free amino POSS were added to 50 parts of n-propanol, and then 1.9 parts of triethylamine and 1.4 parts of allyl chloride were added, heated under reflux at 80°C for 4 h, distilled under reduced pressure, and dried to obtain alkenyl POSS; S3. By weight, 30 parts of alkenyl-functionalized symmetrical phosphorus-containing monomer, 10 parts of alkenyl POSS and 0.06 parts of azobisisobutyronitrile were added to 100 parts of N,N-dimethylformamide. The polymerization reaction was carried out at 80°C for 6 hours under a nitrogen atmosphere. After the reaction was completed, the solvent was removed by rotary evaporation and the product was dried under vacuum to obtain a reactive phosphorus-containing organosilicon macromolecular flame retardant.

[0044] Example 2 This embodiment provides a reactive phosphorus-containing organosilicon macromolecular flame retardant and its preparation method, including the following steps: S1. By weight, 6 parts of terephthalaldehyde and 20 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were added to 150 parts of N,N-dimethylformamide. The mixture was heated to 100°C and stirred for 8 hours under a nitrogen atmosphere. After the reaction was completed, the mixture was distilled under reduced pressure, washed successively with anhydrous ethanol and deionized water, and dried under vacuum to obtain a symmetrical phosphorus-containing monomer. 10 parts of the symmetrical phosphorus-containing monomer and 30 parts of potassium carbonate were added to 200 parts of dimethyl sulfoxide. The mixture was placed under a nitrogen atmosphere and stirred at 60°C for 60 minutes. After cooling to 10°C, 6 parts of 4-vinylbenzyl chloride were added, and the mixture was stirred at 50°C for 8 hours. The mixture was filtered to obtain a filtrate, which was dried, washed with water, and recrystallized to obtain an alkenyl-functionalized symmetrical phosphorus-containing monomer. S2. By weight, 1.6 parts of 3-aminopropyltrimethoxysilane, 2.2 parts of trifluoromethanesulfonic acid, and 30 parts of deionized water were mixed and stirred for 120 min, dried to obtain a crude product, washed with acetone, and dried under vacuum to obtain ammonium salt amino POSS; 4 parts of the ammonium salt amino POSS were added to 40 parts of anhydrous ethanol, and then 3.2 parts of sodium methoxide were added. The mixture was heated to 60°C for 120 min, distilled under reduced pressure, washed with ethyl acetate, and dried under vacuum to obtain free amino POSS; 1.9 parts of free amino POSS were added to 40 parts of n-propanol, and then 1.7 parts of triethylamine and 1.2 parts of allyl chloride were added. The mixture was heated under reflux at 70°C for 6 h, distilled under reduced pressure, and dried to obtain alkenyl POSS; S3. By weight, 20 parts of alkenyl-functionalized symmetrical phosphorus-containing monomer, 6 parts of alkenyl POSS and 0.04 parts of azobisisobutyronitrile were added to 80 parts of N,N-dimethylformamide. The polymerization reaction was carried out at 60°C for 8 hours under a nitrogen atmosphere. After the reaction was completed, the solvent was removed by rotary evaporation and the product was dried under vacuum to obtain a reactive phosphorus-containing organosilicon macromolecular flame retardant.

[0045] Example 3 This embodiment provides a reactive phosphorus-containing organosilicon macromolecular flame retardant and its preparation method, including the following steps: S1. By weight, 7 parts of terephthalaldehyde and 22 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were added to 180 parts of N,N-dimethylformamide. The mixture was heated to 105°C and stirred for 9 hours under a nitrogen atmosphere. After the reaction was completed, the mixture was distilled under reduced pressure, washed successively with anhydrous ethanol and deionized water, and dried under vacuum to obtain a symmetrical phosphorus-containing monomer. 15 parts of the symmetrical phosphorus-containing monomer and 45 parts of potassium carbonate were added to 220 parts of dimethyl sulfoxide. The mixture was placed under a nitrogen atmosphere and stirred at 65°C for 55 minutes. After cooling to 12°C, 9 parts of 4-vinylbenzyl chloride were added. The mixture was then stirred at 55°C for 7 hours. The mixture was filtered to obtain a filtrate. The filtrate was dried, washed with water, and recrystallized to obtain an alkenyl-functionalized symmetrical phosphorus-containing monomer. S2. By weight, 1.7 parts of 3-aminopropyltrimethoxysilane, 2.3 parts of trifluoromethanesulfonic acid, and 35 parts of deionized water were mixed and stirred for 130 min, dried to obtain a crude product, washed with acetone, and dried under vacuum to obtain ammonium salt amino POSS; 5 parts of the ammonium salt amino POSS were added to 50 parts of anhydrous ethanol, and then 3.4 parts of sodium methoxide were added, and the mixture was heated to 65°C for 110 min, distilled under reduced pressure, washed with ethyl acetate, and dried under vacuum to obtain free amino POSS; 2.0 parts of free amino POSS were added to 45 parts of n-propanol, and then 1.8 parts of triethylamine and 1.3 parts of allyl chloride were added, and the mixture was heated under reflux at 75°C for 5 h, distilled under reduced pressure, and dried to obtain alkenyl POSS; S3. By weight, 25 parts of alkenyl-functionalized symmetrical phosphorus-containing monomer, 8 parts of alkenyl POSS and 0.05 parts of azobisisobutyronitrile were added to 90 parts of N,N-dimethylformamide. The polymerization reaction was carried out at 70°C for 7 hours under a nitrogen atmosphere. After the reaction was completed, the solvent was removed by rotary evaporation and the product was dried under vacuum to obtain a reactive phosphorus-containing organosilicon macromolecular flame retardant.

[0046] Application Example 1 This application example provides an additive film and its preparation method. The additive film is prepared using the reactive phosphorus-containing organosilicon macromolecular flame retardant obtained in Example 1, including the following steps: By weight, 20 parts of naphthalene-type epoxy resin (ESN-475V), 60 parts of silica (SO-C2), 15 parts of reactive ester (HPC-8150-60T), 1 part of 1-benzyl-2-phenylimidazolium (1B2PZ), 2 parts of reactive phosphorus-containing organosilicon macromolecular flame retardant prepared in Example 1, and 300 parts of cyclohexanone were mixed evenly and coated onto a substrate to obtain an adhesive film layer. After drying, a protective film was covered to obtain an extended adhesive film.

[0047] Application Example 2 This application example provides a thickening film and its preparation method. The preparation of the thickening film using the reactive phosphorus-containing organosilicon macromolecular flame retardant obtained in Example 2 includes the following steps: By weight, 20 parts of naphthalene-type epoxy resin (ESN-475V), 60 parts of silica (SO-C2), 15 parts of reactive ester (HPC-8150-60T), 1 part of 1-benzyl-2-phenylimidazolium (1B2PZ), 2 parts of reactive phosphorus-containing organosilicon macromolecular flame retardant prepared in Example 2, and 300 parts of cyclohexanone were mixed evenly and coated onto a substrate to obtain an adhesive film layer. After drying, a protective film was covered to obtain an extended adhesive film.

[0048] Application Example 3 This application example provides an additive film and its preparation method. The additive film is prepared using the reactive phosphorus-containing organosilicon macromolecular flame retardant obtained in Example 3, including the following steps: By weight, 20 parts of naphthalene-type epoxy resin (ESN-475V), 60 parts of silica (SO-C2), 15 parts of reactive ester (HPC-8150-60T), 1 part of 1-benzyl-2-phenylimidazolium (1B2PZ), 2 parts of reactive phosphorus-containing organosilicon macromolecular flame retardant prepared in Example 3, and 300 parts of cyclohexanone were mixed evenly and coated onto a substrate to obtain an adhesive film layer. After drying, a protective film was covered to obtain an extended adhesive film.

[0049] Comparative Example 1 This comparative example provides a thickening film and its preparation method. The thickening film is prepared using the alkenyl-functionalized symmetrical phosphorus-containing monomer obtained in step S1 of Example 1, including the following steps: By weight, 20 parts of naphthalene-type epoxy resin (ESN-475V), 60 parts of silica (SO-C2), 15 parts of active ester (HPC-8150-60T), 1 part of 1-benzyl-2-phenylimidazolium (1B2PZ), 2 parts of the alkenyl-functionalized symmetrical phosphorus-containing monomer prepared in Example 1, and 300 parts of cyclohexanone were mixed evenly and coated onto a substrate to obtain an adhesive film layer. After drying, a protective film was covered to obtain an extended adhesive film.

[0050] Comparative Example 2 This comparative example provides a thickening film and its preparation method. The thickening film is prepared using the alkenyl POSS obtained in step S2 of Example 1, including the following steps: By weight, 20 parts of naphthalene-type epoxy resin (ESN-475V), 60 parts of silica (SO-C2), 15 parts of active ester (HPC-8150-60T), 1 part of 1-benzyl-2-phenylimidazolium (1B2PZ), 2 parts of alkenyl POSS as described in Preparation Example 1, and 300 parts of cyclohexanone were mixed evenly and coated onto a substrate to obtain an adhesive film layer. After drying, a protective film was covered to obtain an extended adhesive film.

[0051] The performance of the laminated films prepared in the above application examples and comparative examples was tested using the following methods: (1) Flame retardancy: After removing the protective film, the laminate film with release film is pressed onto the substrate using a laminating machine. The laminate film (the side without release film) is pressed onto both sides of the substrate to obtain a laminate. After lamination, the release film on the laminate is removed, and the film layer is heat-cured (at 190°C for 90 minutes) to form a cured product on both sides of the substrate. The laminate (thickness of about 380 μm) is cut into pieces of 12.7 mm × 127 mm with an edge of 1.27 mm. The test is conducted according to the UL-94V standard, and the test results are recorded. The results are shown in Table 1.

[0052] (2) Dielectric constant and dielectric loss tangent: Remove the protective film, cure the release film-coated adhesive at 190℃ for 90 min, and then peel off the release film to obtain the cured adhesive film; cut the cured adhesive film into 2mm×80mm test pieces (3 pieces), and then use Agilent Technologies' "HP8362B" to measure the dielectric loss tangent of each test piece under the conditions of a measurement frequency of 5.8GHz and a measurement temperature of 23℃. The average value of the 3 test pieces is the dielectric loss tangent. The results are shown in Table 1.

[0053] Table 1

[0054] The results show that the reactive phosphorus-containing organosilicon macromolecular flame retardants prepared in Examples 1-3 of this invention can significantly improve the flame retardant properties of the laminated film and reduce the dielectric constant and dielectric loss tangent. Their overall electrical properties are significantly better than those prepared solely through alkenyl functionalized symmetrical phosphorus-containing monomers or solely through alkenyl POSS. The phosphorus-containing groups of the reactive phosphorus-containing organosilicon macromolecular flame retardants prepared in this invention interact with the epoxy resin in the laminated film, catalyzing the dehydration and cross-linking reactions of the epoxy resin to form a dense, porous carbon layer. Subsequently, some of the silica in the laminated film is transferred to the surface of the carbon layer, forming a glassy protective layer under the action of phosphorus. Through the synergistic effect of the flame retardant and other components, the flame retardancy of the material is improved.

[0055] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a reactive phosphorus-containing organosilicon macromolecular flame retardant, characterized in that, Includes the following steps: S1. Provide a symmetrical phosphorus-containing monomer, and react the symmetrical phosphorus-containing monomer with 4-vinylbenzyl chloride to obtain an alkenyl-functionalized symmetrical phosphorus-containing monomer; S2. 3-Aminopropyltrimethoxysilane is reacted with an acid catalyst to obtain ammonium salt amino POSS; the ammonium salt amino POSS is reacted with a base by heating to obtain free amino POSS; the free amino POSS is mixed with triethylamine and allyl chloride and heated under reflux to obtain alkenyl POSS; S3. Mix the alkenyl-functionalized symmetrical phosphorus-containing monomer and the alkenyl POSS and carry out a polymerization reaction to obtain the reactive phosphorus-containing organosilicon macromolecular flame retardant. The structural formula of the symmetrical phosphorus-containing monomer is: .

2. The preparation method according to claim 1, characterized in that, In step S1, providing the symmetrical phosphorus-containing monomer specifically includes reacting 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide with terephthalaldehyde to obtain the symmetrical phosphorus-containing monomer.

3. The preparation method according to claim 2, characterized in that, In step S1, the mass ratio of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide to terephthalaldehyde is 1:0.2~0.4; and / or, the mass ratio of the symmetrical phosphorus-containing monomer to 4-vinylbenzyl chloride is 1:0.3~1.

2.

4. The preparation method according to claim 1, characterized in that, In step S2, the acid catalyst is at least one of trifluoromethanesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, hydrochloric acid, nitric acid, and trifluoroacetic acid.

5. The preparation method according to claim 1, characterized in that, In step S2, the alkali is at least one of sodium methoxide, sodium hydroxide, potassium hydroxide, and sodium ethoxide.

6. The preparation method according to claim 1, characterized in that, In step S2, the mass ratio of 3-aminopropyltrimethoxysilane to the acid catalyst is 1:1.0~1.5; and / or, the mass ratio of the ammonium salt amino POSS to the base is 1:0.5~1; and / or, the mass ratio of the free amino POSS to triethylamine and allyl chloride is 1:0.8~1.0:0.5~0.

8.

7. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of the alkenyl-functionalized symmetrical phosphorus-containing monomer to alkenyl POSS is 1:0.2~0.

5.

8. The preparation method according to claim 1, characterized in that, In step S3, the polymerization reaction of mixing the alkenyl-functionalized symmetrical phosphorus-containing monomer and the alkenyl POSS specifically includes: adding the alkenyl-functionalized symmetrical phosphorus-containing monomer, alkenyl POSS and azobisisobutyronitrile to a solvent, and heating to 60~80℃ under a nitrogen atmosphere for 6~8h for polymerization reaction.

9. A reactive phosphorus-containing organosilicon macromolecular flame retardant, characterized in that, The reactive phosphorus-containing organosilicon macromolecular flame retardant is prepared by the preparation method described in any one of claims 1-8.

10. The application of a reactive phosphorus-containing organosilicon macromolecular flame retardant in coated films, characterized in that, The reactive phosphorus-containing organosilicon macromolecular flame retardant is prepared by the preparation method described in any one of claims 1-8.

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