Preparation method of flame-retardant polycarbonate containing TiO2 and heterocyclic compounds

Abstract

This invention discloses a method for preparing flame-retardant polycarbonate containing TiO2 and heterocyclic compounds, comprising: uniformly mixing paraformaldehyde, 2,4-diamino-6-phenyl-1,3,5-triazine and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heating and reacting, and obtaining the heterocyclic compound by filtration, distillation and drying; uniformly mixing anhydrous ethylenediamine and distilled water, adding lysine and tetrabutyl titanate, transferring to a reaction vessel, heating and reacting, cooling to room temperature, filtering and washing three times each with anhydrous ethanol and distilled water, and drying to obtain aminated TiO2; then dissolving the aminated TiO2 and the heterocyclic compound in dioxane and reacting under nitrogen atmosphere to obtain functionalized TiO2; and extruding and granulating the functionalized TiO2 with polycarbonate to obtain flame-retardant polycarbonate granules. Functionalized TiO2, as a modifier, can be blended to comprehensively improve the flame retardancy, mechanical strength, and solvent resistance of polycarbonate, thereby enhancing its flame retardancy.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a method for preparing flame-retardant polycarbonate containing TiO2 and heterocyclic compounds. Background Technology

[0002] Polycarbonate (PC) is a class of polymers containing carbonate groups in its molecular chain, with bisphenol A type PC being the most common. PC has a high glass transition temperature (145-155℃), high flow temperature, high melt viscosity, and a rigid benzene ring structure that results in minimal deformation under external forces, leading to dimensional stability in manufactured products. PC exhibits excellent tensile strength and high impact strength at room temperature. It also possesses excellent electrical properties, with low volume resistivity and dielectric constant, resulting in excellent insulation performance, making it widely used in components of electronic and mechanical industrial products. However, in practical applications, PC is flammable when exposed to open flames or high temperatures, releasing high concentrations of resin dust that can inhale into the lungs. Therefore, it is necessary to improve the high-temperature flame-retardant properties of PC.

[0003] To improve the flame retardant properties of polycarbonate (PC), a common method is to melt-blend PC with flame retardants. Early flame retardants were halogenated, but these decompose at high temperatures, producing large amounts of smoky and toxic corrosive hydrogen halide gases. Therefore, current research focuses on halogen-free flame retardants. However, current polycarbonate (PC) still suffers from poor flame retardancy. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing flame-retardant polycarbonate containing TiO2 and heterocyclic compounds, aiming to solve the problem that current polycarbonate (PC) still has poor flame retardancy.

[0005] To achieve the above objectives, the present invention provides a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds, comprising the following steps:

[0006] Paraformaldehyde, 2,4-diamino-6-phenyl-1,3,5-triazine and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were mixed evenly, heated to react, and then the heterocyclic compound was obtained by filtration, distillation and drying.

[0007] Anhydrous ethylenediamine and distilled water were mixed evenly, lysine and tetrabutyl titanate were added, the mixture was transferred into a reaction vessel, heated to react, cooled to room temperature, filtered and washed three times each with anhydrous ethanol and distilled water, and dried to obtain aminated TiO2. The aminated TiO2 and the heterocyclic compound were then dissolved in dioxane and reacted under nitrogen atmosphere to obtain functionalized TiO2.

[0008] Flame-retardant polycarbonate granules were prepared by extrusion and granulation of the functionalized TiO2 and polycarbonate.

[0009] In one embodiment, paraformaldehyde, 2,4-diamino-6-phenyl-1,3,5-triazine and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed evenly, heated to react, and then the heterocyclic compound is obtained by filtration, distillation and drying.

[0010] Anhydrous ethylenediamine and distilled water were mixed evenly, lysine and tetrabutyl titanate were added, the mixture was transferred into a reaction vessel, heated to react, cooled to room temperature, filtered and washed three times each with anhydrous ethanol and distilled water, and dried to obtain aminated TiO2. The aminated TiO2 and the heterocyclic compound were then dissolved in dioxane and reacted under nitrogen atmosphere to obtain functionalized TiO2.

[0011] Flame-retardant polycarbonate granules were prepared by extrusion and granulation of the functionalized TiO2 and polycarbonate.

[0012] In one embodiment, paraformaldehyde, 2,4-diamino-6-phenyl-1,3,5-triazine, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed uniformly, and the specific steps include:

[0013] Paraformaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed in a molar ratio of 1:1 to 1:3 to obtain a first mixture. The first mixture is dissolved in dioxane in a mass ratio of 8:1 and reacted at room temperature for 1 hour to obtain a second mixture. An equimolar amount of 2,4-diamino-6-phenyl-1,3,5-triazine, which is equal to that in the first mixture, is added to the second mixture.

[0014] In one embodiment, the reaction is heated, and then the heterocyclic compound is obtained by filtration, distillation, and drying. Specific steps include:

[0015] The reaction was carried out at 70℃~110℃ for 18h, followed by heating. The heterocyclic compound was then obtained by filtration, distillation, and drying.

[0016] In one embodiment, anhydrous ethylenediamine and distilled water are mixed evenly, lysine and tetrabutyl titanate are added, the mixture is transferred to a reaction vessel, heated to react, and then cooled to room temperature. Specific steps include:

[0017] Anhydrous ethylenediamine and distilled water were mixed evenly at a mass ratio of 1:15 to 1:20. Lysine and tetrabutyl titanate were added at a molar ratio of 1:1 to 1:3. The mixture was then transferred to a 50 ml reaction vessel and heated at 65℃ to 90℃ for 10 to 15 hours before being cooled to room temperature.

[0018] In one embodiment, the aminated TiO2 and the heterocyclic compound are further dissolved in dioxane, wherein the molar ratio of the aminated TiO2 to the heterocyclic compound is 1:50 to 1:200.

[0019] In one embodiment, the reaction takes place under a nitrogen atmosphere, and the specific steps include:

[0020] The reaction was carried out at 60℃~85℃ for 4.5h under nitrogen atmosphere.

[0021] In one embodiment, the aminated TiO2 and the heterocyclic compound are further dissolved in dioxane, wherein the mass ratio of the aminated TiO2 to the dioxane is 1:10 to 1:20.

[0022] In one embodiment, flame-retardant polycarbonate granules are prepared by extrusion and granulation of the functionalized TiO2 and polycarbonate, wherein the mass ratio of the functionalized TiO2 to the polycarbonate is 1:10 to 1:18; and the extrusion temperature is 260°C.

[0023] This invention discloses a method for preparing flame-retardant polycarbonate containing TiO2 and heterocyclic compounds. The specific steps include: uniformly mixing paraformaldehyde, 2,4-diamino-6-phenyl-1,3,5-triazine, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heating and reacting, followed by filtration, distillation, and drying to obtain the heterocyclic compound; uniformly mixing anhydrous ethylenediamine and distilled water, adding lysine and tetrabutyl titanate, transferring to a reaction vessel, heating and reacting, cooling to room temperature, filtering, and washing three times each with anhydrous ethanol and distilled water, and drying to obtain aminated TiO2; dissolving the aminated TiO2 and the heterocyclic compound in dioxane and reacting under nitrogen to obtain functionalized TiO2; and extruding and granulating the functionalized TiO2 with polycarbonate to obtain flame-retardant polycarbonate granules. Functionalized TiO2 can be used as a modifier to modify PC, and through blending, it can comprehensively improve the flame-retardant properties, mechanical strength, and solvent resistance of PC. Functionalized TiO2 can be blended well with polycarbonate. On the basis of improving the overall performance of polycarbonate such as flame retardancy, TiO2 further improves the flame retardancy of polycarbonate. The overall performance is better when the mass ratio of functionalized TiO2 to polycarbonate is 1:10-1:15. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic flowchart of a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the first embodiment of the present invention.

[0026] Figure 2 This is a schematic flowchart of a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the second embodiment of the present invention.

[0027] Figure 3 This is a schematic flowchart of a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the third embodiment of the present invention.

[0028] Figure 4 This is a schematic flowchart of a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the fourth embodiment of the present invention.

[0029] Figure 5 This is a schematic flowchart of a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the fifth embodiment of the present invention.

[0030] Figure 6 This is a schematic flowchart of a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the sixth embodiment of the present invention.

[0031] Figure 7 This is a schematic flowchart of a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the seventh embodiment of the present invention.

[0032] Figure 8 This is a schematic flowchart of a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the eighth embodiment of the present invention.

[0033] Figure 9 This is a schematic flowchart of a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the ninth embodiment of the present invention. Detailed Implementation

[0034] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0035] Please see Figure 1 , Figure 1This is a schematic flowchart illustrating a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the first embodiment of the present invention. Specifically, the method for preparing the flame-retardant polycarbonate containing TiO2 and heterocyclic compounds may include the following steps:

[0036] S101. Preparation of heterocyclic compound: Paraformaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) are mixed at a molar ratio of 1:3 to obtain a first mixture. The first mixture is dissolved in dioxane at a mass ratio of 8:1 and reacted at room temperature for 1 h to obtain a second mixture. An equimolar amount of 2,4-diamino-6-phenyl-1,3,5-triazine is added to the second mixture and reacted at 100 °C for 18 h. The product heterocyclic compound (BDP) is then obtained through a filtration-distillation-drying process.

[0037] Functional modification of S102 and TiO2: Anhydrous ethylenediamine and distilled water were mixed evenly at a mass ratio of 1:20. Lysine and tetrabutyl titanate were added at a molar ratio of 1:1. The mixture was transferred to a 50ml reactor and heated at 80℃ for 10h. After cooling to room temperature, the mixture was filtered and washed three times each with anhydrous ethanol and distilled water. After drying, aminated TiO2 was obtained. Then, TiO2 and heterocyclic compounds were dissolved in dioxane at a molar ratio of 1:200. The mass ratio of aminated TiO2 to dioxane was 1:15. The mixture was reacted at 70℃ for 4.5h under nitrogen atmosphere to obtain functionalized TiO2.

[0038] S103, Preparation of flame-retardant PC composite material: Functionalized TiO2 and PC are extruded and granulated at a mass ratio of 1:10 through a 260℃ extrusion-granulation system to obtain flame-retardant PC granules.

[0039] Please see Figure 2 , Figure 2 This is a schematic flow chart of a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to a second embodiment of the present invention. Specifically, the method for preparing the flame-retardant polycarbonate containing TiO2 and heterocyclic compounds may include the following steps:

[0040] S201. Preparation of heterocyclic compound: Paraformaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed at a molar ratio of 1:2 to obtain a first mixture. The first mixture is dissolved in dioxane at a mass ratio of 8:1 and reacted at room temperature for 1 h to obtain a second mixture. An equimolar amount of 2,4-diamino-6-phenyl-1,3,5-triazine is added to the second mixture and reacted at 70 °C for 18 h. The product heterocyclic compound (BDP) is then obtained through a filtration-distillation-drying process.

[0041] S202. Anhydrous ethylenediamine and distilled water are mixed evenly at a mass ratio of 1:15. Lysine and tetrabutyl titanate are added at a molar ratio of 1:1. The mixture is transferred to a 50ml reaction vessel and heated at 70℃ for 15h. After cooling to room temperature, the mixture is filtered and washed three times each with anhydrous ethanol and distilled water. After drying, aminated TiO2 is obtained. Then, TiO2 and heterocyclic compounds are dissolved in dioxane at a molar ratio of 1:50. The mass ratio of aminated TiO2 to dioxane is 1:10. The mixture is reacted at 60℃ for 4.5h under nitrogen atmosphere to obtain functionalized TiO2.

[0042] Preparation of S203 and flame-retardant PC composite materials: Functionalized TiO2 and PC were extruded and granulated at a mass ratio of 1:11 through a 260℃ extrusion-granulation system to obtain flame-retardant PC granules.

[0043] Please see Figure 3 , Figure 3 This is a schematic flowchart illustrating a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to a third embodiment of the present invention. Specifically, the method for preparing the flame-retardant polycarbonate containing TiO2 and heterocyclic compounds may include the following steps:

[0044] S301. Preparation of heterocyclic compound: Paraformaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed at a molar ratio of 1:1 to obtain a first mixture. The first mixture is dissolved in dioxane at a mass ratio of 8:1 and reacted at room temperature for 1 hour to obtain a second mixture. An equimolar amount of 2,4-diamino-6-phenyl-1,3,5-triazine is added to the second mixture and reacted at 75°C for 18 hours. The product heterocyclic compound (BDP) is then obtained through a filtration-distillation-drying process.

[0045] S302. Anhydrous ethylenediamine and distilled water are mixed evenly at a mass ratio of 1:20. Lysine and tetrabutyl titanate are then added at a molar ratio of 1:2. The mixture is transferred to a 50ml reaction vessel and heated at 75℃ for 15h. After cooling to room temperature, the mixture is filtered and washed three times each with anhydrous ethanol and distilled water. After drying, aminated TiO2 is obtained. Then, TiO2 and heterocyclic compounds are dissolved in dioxane at a molar ratio of 1:100. The mass ratio of aminated TiO2 to dioxane is 1:13. The mixture is reacted at 65℃ for 4.5h under nitrogen atmosphere to obtain functionalized TiO2.

[0046] Preparation of S303 flame-retardant PC composite material: Functionalized TiO2 and PC are extruded and granulated at a mass ratio of 1:12 through a 260℃ extrusion-granulation system to obtain flame-retardant PC granules.

[0047] Please see Figure 4 , Figure 4This is a schematic flowchart illustrating a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the fourth embodiment of the present invention. Specifically, the method for preparing the flame-retardant polycarbonate containing TiO2 and heterocyclic compounds may include the following steps:

[0048] S401. Preparation of heterocyclic compound: Paraformaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed at a molar ratio of 1:3 to obtain a first mixture. The first mixture is dissolved in dioxane at a mass ratio of 8:1 and reacted at room temperature for 1 h to obtain a second mixture. An equimolar amount of 2,4-diamino-6-phenyl-1,3,5-triazine is added to the second mixture and reacted at 80 °C for 18 h. The product heterocyclic compound (BDP) is then obtained through a filtration-distillation-drying process.

[0049] S402. Anhydrous ethylenediamine and distilled water are mixed evenly at a mass ratio of 1:20. Then, lysine and tetrabutyl titanate are added at a molar ratio of 1:3. The mixture is transferred to a 50ml reaction vessel and heated at 65℃ for 15h. After cooling to room temperature, the mixture is filtered and washed three times each with anhydrous ethanol and distilled water. After drying, aminated TiO2 is obtained. Then, TiO2 and heterocyclic compounds are dissolved in dioxane at a molar ratio of 1:150. The mass ratio of aminated TiO2 to dioxane is 1:20. The mixture is reacted at 75℃ for 4.5h under nitrogen atmosphere to obtain functionalized TiO2.

[0050] Preparation of S403 flame-retardant PC composite material: Functionalized TiO2 and PC are extruded and granulated at a mass ratio of 1:13 through a 260℃ extrusion-granulation system to obtain flame-retardant PC granules.

[0051] Please see Figure 5 , Figure 5 This is a schematic flowchart illustrating a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the fifth embodiment of the present invention. Specifically, the method for preparing the flame-retardant polycarbonate containing TiO2 and heterocyclic compounds may include the following steps:

[0052] S501. Preparation of heterocyclic compound: Paraformaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed at a molar ratio of 1:2 to obtain a first mixture. The first mixture is dissolved in dioxane at a mass ratio of 8:1 and reacted at room temperature for 1 h to obtain a second mixture. An equimolar amount of 2,4-diamino-6-phenyl-1,3,5-triazine is added to the second mixture and reacted at 85°C for 18 h. The product heterocyclic compound (BDP) is then obtained through a filtration-distillation-drying process.

[0053] S502. Anhydrous ethylenediamine and distilled water are mixed evenly at a mass ratio of 1:20. Then, lysine and tetrabutyl titanate are added at a molar ratio of 1:1. The mixture is transferred to a 50ml reaction vessel and heated at 75℃ for 15h. After cooling to room temperature, the mixture is filtered and washed three times each with anhydrous ethanol and distilled water. After drying, aminated TiO2 is obtained. Then, TiO2 and heterocyclic compounds are dissolved in dioxane at a molar ratio of 1:200. The mass ratio of aminated TiO2 to dioxane is 1:20. The mixture is reacted at 80℃ for 4.5h under nitrogen atmosphere to obtain functionalized TiO2.

[0054] Preparation of S503 flame-retardant PC composite material: Functionalized TiO2 and PC are extruded and granulated at a mass ratio of 1:14 through a 260℃ extrusion-granulation system to obtain flame-retardant PC granules.

[0055] Please see Figure 6 , Figure 6 This is a schematic flowchart illustrating a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the sixth embodiment of the present invention. Specifically, the method for preparing the flame-retardant polycarbonate containing TiO2 and heterocyclic compounds may include the following steps:

[0056] S601. Preparation of heterocyclic compound: Paraformaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed at a molar ratio of 1:1 to obtain a first mixture. The first mixture is dissolved in dioxane at a mass ratio of 8:1 and reacted at room temperature for 1 h to obtain a second mixture. An equimolar amount of 2,4-diamino-6-phenyl-1,3,5-triazine is added to the second mixture and reacted at 90 °C for 18 h. The product heterocyclic compound (BDP) is then obtained through a filtration-distillation-drying process.

[0057] S602. Anhydrous ethylenediamine and distilled water are mixed evenly at a mass ratio of 1:20. Then, lysine and tetrabutyl titanate are added at a molar ratio of 1:3. The mixture is transferred to a 50ml reaction vessel and heated at 80℃ for 15h. After cooling to room temperature, the mixture is filtered and washed three times each with anhydrous ethanol and distilled water. After drying, aminated TiO2 is obtained. Then, TiO2 and heterocyclic compounds are dissolved in dioxane at a molar ratio of 1:100. The mass ratio of aminated TiO2 to dioxane is 1:20. The mixture is reacted at 85℃ for 4.5h under nitrogen atmosphere to obtain functionalized TiO2.

[0058] Preparation of S603 flame-retardant PC composite material: Functionalized TiO2 and PC are extruded and granulated at a mass ratio of 1:15 through a 260℃ extrusion-granulation system to obtain flame-retardant PC granules.

[0059] Please see Figure 7 , Figure 7This is a schematic flowchart illustrating a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the seventh embodiment of the present invention. Specifically, the method for preparing the flame-retardant polycarbonate containing TiO2 and heterocyclic compounds may include the following steps:

[0060] S701. Preparation of heterocyclic compound: Paraformaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed at a molar ratio of 1:3 to obtain a first mixture. The first mixture is dissolved in dioxane at a mass ratio of 8:1 and reacted at room temperature for 1 h to obtain a second mixture. An equimolar amount of 2,4-diamino-6-phenyl-1,3,5-triazine is added to the second mixture and reacted at 95 °C for 18 h. The product heterocyclic compound (BDP) is then obtained through a filtration-distillation-drying process.

[0061] S702. Anhydrous ethylenediamine and distilled water are mixed evenly at a mass ratio of 1:20. Lysine and tetrabutyl titanate are added at a molar ratio of 1:1. The mixture is transferred to a 50ml reaction vessel and heated at 85℃ for 15h. After cooling to room temperature, the mixture is filtered and washed three times each with anhydrous ethanol and distilled water. After drying, aminated TiO2 is obtained. Then, TiO2 and heterocyclic compounds are dissolved in dioxane at a molar ratio of 1:150. The mass ratio of aminated TiO2 to dioxane is 1:20. The mixture is reacted at 75℃ for 4.5h under nitrogen atmosphere to obtain functionalized TiO2.

[0062] Preparation of S703 flame-retardant PC composite material: Functionalized TiO2 and PC are extruded and granulated at a mass ratio of 1:16 through a 260℃ extrusion-granulation system to obtain flame-retardant PC granules.

[0063] Please see Figure 8 , Figure 8 This is a schematic flowchart illustrating a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the eighth embodiment of the present invention. Specifically, the method for preparing the flame-retardant polycarbonate containing TiO2 and heterocyclic compounds may include the following steps:

[0064] S801. Preparation of heterocyclic compound: Paraformaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed at a molar ratio of 1:2 to obtain a first mixture. The first mixture is dissolved in dioxane at a mass ratio of 8:1 and reacted at room temperature for 1 hour to obtain a second mixture. An equimolar amount of 2,4-diamino-6-phenyl-1,3,5-triazine is added to the second mixture and reacted at 100°C for 18 hours. The product heterocyclic compound (BDP) is then obtained through a filtration-distillation-drying process.

[0065] S802. Anhydrous ethylenediamine and distilled water are mixed evenly at a mass ratio of 1:20. Then, lysine and tetrabutyl titanate are added at a molar ratio of 1:1. The mixture is transferred to a 50ml reaction vessel and heated at 90℃ for 10h. After cooling to room temperature, the mixture is filtered and washed three times each with anhydrous ethanol and distilled water. After drying, aminated TiO2 is obtained. Then, TiO2 and heterocyclic compounds are dissolved in dioxane at a molar ratio of 1:200. The mass ratio of aminated TiO2 to dioxane is 1:20. The mixture is reacted at 80℃ for 4.5h under nitrogen atmosphere to obtain functionalized TiO2.

[0066] Preparation of S803 flame-retardant PC composite material: Functionalized TiO2 and PC are extruded and granulated at a mass ratio of 1:17 through a 260℃ extrusion-granulation system to obtain flame-retardant PC granules.

[0067] Please see Figure 9 , Figure 9 This is a schematic flowchart illustrating a method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds according to the ninth embodiment of the present invention. Specifically, the method for preparing the flame-retardant polycarbonate containing TiO2 and heterocyclic compounds may include the following steps:

[0068] S901. Preparation of heterocyclic compound: Paraformaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed at a molar ratio of 1:1 to obtain a first mixture. The first mixture is dissolved in dioxane at a mass ratio of 8:1 and reacted at room temperature for 1 h to obtain a second mixture. An equimolar amount of 2,4-diamino-6-phenyl-1,3,5-triazine is added to the second mixture and reacted at 110 °C for 18 h. The product heterocyclic compound (BDP) is then obtained through a filtration-distillation-drying process.

[0069] S902. Anhydrous ethylenediamine and distilled water are mixed evenly at a mass ratio of 1:20. Then, lysine and tetrabutyl titanate are added at a molar ratio of 1:3. The mixture is transferred to a 50ml reaction vessel and heated at 90℃ for 15h. After cooling to room temperature, the mixture is filtered and washed three times each with anhydrous ethanol and distilled water. After drying, aminated TiO2 is obtained. Then, TiO2 and heterocyclic compounds are dissolved in dioxane at a molar ratio of 1:150. The mass ratio of aminated TiO2 to dioxane is 1:20. The mixture is reacted at 85℃ for 4.5h under nitrogen atmosphere to obtain functionalized TiO2.

[0070] Preparation of S903 flame-retardant PC composite material: Functionalized TiO2 and PC are extruded and granulated at a mass ratio of 1:18 through a 260℃ extrusion-granulation system to obtain flame-retardant PC granules.

[0071] The paraformaldehyde in the first to ninth embodiments is a first-grade product with a purity of 95%; the heterocyclic compound is bisphenol A-bis(diphenyl phosphate) (BDP). The schematic diagram of the chemical structure of the obtained heterocyclic compound is as follows:

[0072]

[0073] Compare with Example 1

[0074] Standard specimens were injection molded from pure PC for testing.

[0075] Compare with Example 2

[0076] Unfunctionalized TiO2 and PC were melt-blended at a mass ratio of 1:10 and injection-molded into standard specimens for testing.

[0077] Compare with Example 3

[0078] (1) Preparation of heterocyclic compound: Paraformaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide were mixed at a molar ratio of 1:3 to obtain a first mixture. The first mixture was dissolved in dioxane at a mass ratio of 8:1 and reacted at room temperature for 1 h to obtain a second mixture. An equimolar amount of 2,4-diamino-6-phenyl-1,3,5-triazine was added to the second mixture and reacted at 100 °C for 18 h. The product heterocyclic compound (BDP) was then obtained through a filtration-distillation-drying process.

[0079] (2) Preparation of flame-retardant PC composite material: Flame-retardant PC granules were prepared by mixing P / N heterocyclic compounds and PC at a mass ratio of 1:10 through a mixing-extrusion-granulation system. The mixing temperature was 250℃, and the extrusion temperature was 260℃. Standard specimens were injection molded for testing.

[0080] Application performance testing

[0081] The flame-retardant reinforced PC composite materials prepared in Examples 1-9 and Comparative Examples 1-3 were injection molded into standard specimens and subjected to limiting oxygen index and impact performance tests in accordance with GB / T 1040-2006 and GB / T 1843-2008. The PC grade was Teijin K-1300 from Japan. The test results are shown in Table 1.

[0082] Table 1

[0083]

[0084] The data above shows that:

[0085] (1) As can be seen from control group 1 and control group 2, pure TiO2 has a certain effect on improving the tensile strength and limiting oxygen index of PC. The performance of the composite material after functionalized TiO2 and PC blend is generally better than that of pure TiO2 and PC blend.

[0086] (2) When preparing the P / N heterocyclic compound of the present invention, the highest yield of the P / N heterocyclic compound is obtained when the ratio of paraformaldehyde, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 2,4-diamino-6-phenyl-1,3,5-triazine is 1:2:1, the reaction temperature is 100℃, and the reaction time is 18h.

[0087] (3) During the preparation process, when the ratio of functionalized TiO2 to PC is 1:17-1:18, the comprehensive performance reaches the best, the limiting oxygen index can reach up to 30.1%, the flame retardant performance is excellent, and the mechanical strength and toughness are improved to a certain extent.

[0088] This invention discloses a method for preparing flame-retardant polycarbonate containing TiO2 and heterocyclic compounds. The specific steps include: uniformly mixing paraformaldehyde, 2,4-diamino-6-phenyl-1,3,5-triazine, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, heating and reacting, followed by filtration, distillation, and drying to obtain the heterocyclic compound; uniformly mixing anhydrous ethylenediamine and distilled water, adding lysine and tetrabutyl titanate, transferring to a reaction vessel, heating and reacting, cooling to room temperature, filtering, and washing three times each with anhydrous ethanol and distilled water, and drying to obtain aminated TiO2; dissolving the aminated TiO2 and the heterocyclic compound in dioxane and reacting under nitrogen to obtain functionalized TiO2; and extruding and granulating the functionalized TiO2 with polycarbonate to obtain flame-retardant polycarbonate granules. Functionalized TiO2 can be used as a modifier to modify PC, and through blending, it can comprehensively improve the flame-retardant properties, mechanical strength, and solvent resistance of PC. Functionalized TiO2 can be blended well with polycarbonate. On the basis of improving the overall performance of polycarbonate such as flame retardancy, TiO2 further improves the flame retardancy of polycarbonate. The overall performance is better when the mass ratio of functionalized TiO2 to polycarbonate is 1:10-1:15.

[0089] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A method for preparing a flame-retardant polycarbonate containing TiO2 and heterocyclic compounds, characterized in that, Includes the following steps: Paraformaldehyde, 2,4-diamino-6-phenyl-1,3,5-triazine, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide are mixed uniformly and heated to react. The resulting heterocyclic compound is then obtained by filtration, distillation, and drying. Specifically, the steps include: mixing paraformaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide at a molar ratio of 1:1 to 1:3 to obtain a first mixture; dissolving the first mixture in dioxane at a mass ratio of 8:1 and reacting at room temperature for 1 hour to obtain a second mixture; adding 2,4-diamino-6-phenyl-1,3,5-triazine in an equimolar amount to the first mixture to the second mixture; reacting at 70°C to 110°C for 18 hours with heating; and then obtaining the heterocyclic compound by filtration, distillation, and drying. Anhydrous ethylenediamine and distilled water were mixed evenly at a mass ratio of 1:15 to 1:

20. Lysine and tetrabutyl titanate were added at a molar ratio of 1:1 to 1:

3. The mixture was transferred to a 50 ml reactor and heated at 65°C to 90°C for 10 to 15 hours. After cooling to room temperature, the mixture was filtered and washed three times each with anhydrous ethanol and distilled water. The mixture was then dried to obtain aminated TiO2. The aminated TiO2 and the heterocyclic compound were dissolved in dioxane, wherein the molar ratio of the aminated TiO2 to the heterocyclic compound was 1:50 to 1:

200. The mixture was reacted at 60°C to 85°C for 4.5 hours under nitrogen atmosphere to obtain functionalized TiO2. The mass ratio of the aminated TiO2 to the dioxane was 1:10 to 1:

20. Flame-retardant polycarbonate granules are prepared by extrusion and granulation of the functionalized TiO2 and polycarbonate, wherein the mass ratio of the functionalized TiO2 to the polycarbonate is 1:10 to 1:18; and the extrusion temperature is 260°C.

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