Preparation method of halogen-free flame-retardant PC plastic material

Abstract

The present application relates to the technical field of polycarbonate, and discloses a preparation method of halogen-free flame-retardant PC plastic material.Polycarbonate and triazine sulfonate-based silicone oil flame retardant are blended in a torque rheometer to obtain the halogen-free flame-retardant PC plastic material.The sulfonate groups in the flame retardant can catalyze the crosslinking of polycarbonate into carbon, and the polysiloxane pyrolyzes to form a Si-C layer on the surface of polycarbonate, and the triazine groups pyrolyze to produce nitrogen and other non-combustible gases, thereby improving the limiting oxygen index, UL94 grade and flame-retardant performance of the polycarbonate plastic material.The triazine sulfonate-based silicone oil flame retardant contains hydroxyl groups and imino groups, has good compatibility with polycarbonate, and has a flexible polysiloxane main chain, so that good toughening effect can be achieved, and the bending strength and impact strength of the polycarbonate material are improved.

Description

Technical Field

[0001] This invention relates to the field of polycarbonate technology, specifically to a method for preparing halogen-free flame-retardant PC plastic material. Background Technology

[0002] Polycarbonate, colorless and transparent, possesses high mechanical strength, good heat resistance, and excellent processing properties. It is a general-purpose engineering plastic widely used in electronics, the automotive industry, building materials, and medical devices. Improving the flame retardant properties of polycarbonate is of great significance. Common flame retardants for polycarbonate include halogenated flame retardants, sulfonate flame retardants, nitrogen-phosphorus flame retardants, and silicone-based flame retardants. Developing green and environmentally friendly halogen-free flame retardants is a research hotspot.

[0003] Polysiloxanes, such as silicone oil and hydrogen-containing silicone oil, are a class of organosilicon polymers with excellent chemical stability, high-temperature resistance, and insulation properties. They have important applications in toughening agents, flame retardants, and fabric finishing agents. Patent CN116332983B discloses a modified cyclic siloxane flame retardant formed by combining sulfonated cyclic siloxanes with alkali metals, which improves the flame retardant properties of polycarbonate. However, this patent does not significantly improve the flexural strength, impact strength, or other mechanical properties of polycarbonate. Summary of the Invention

[0004] The technical problem solved by this invention is to provide a PC polycarbonate plastic material with good mechanical properties and excellent flame retardancy.

[0005] The present invention provides a method for preparing a halogen-free flame-retardant PC plastic material, comprising the following steps:

[0006] Step A: Toluene, hydrogen-containing silicone oil, 2-methylallyloxy-4,6-bis(glycidyl ether)-1,3,5-triazine, and chloroplatinic acid-isopropanol solution are added to a reaction vessel, nitrogen gas is introduced, and the mixture is heated to 100-110℃. The mixture is then refluxed for 6-12 hours, rotary evaporated, and dried to obtain glycidyl ether triazine modified silicone oil.

[0007] Step B: Add tetrahydrofuran, glycidyl ether triazine silicone oil (mass ratio 100:(120-150)), and sodium 4-aminobenzenesulfonate to a reaction vessel, heat to 40-50℃, stir for 5-8 hours, rotary evaporate, add methanol, filter, and dry to obtain triazine sulfonate silicone oil flame retardant. The reaction formula is:

[0008]

[0009] Step C: Mix polycarbonate and triazine sulfonate-based silicone oil flame retardant at a mass ratio of 100:(1-8) at 270-280℃ for 15-20 minutes, then discharge to obtain halogen-free flame-retardant PC plastic material.

[0010] Preferably, in step A, the molar ratio of the SiH group of the hydrosilicone oil to 2-methylallyloxy-4,6-bis(glycidyl ether)-1,3,5-triazine is (1-1.2):1. The mass ratio of 2-methylallyloxy-4,6-bis(glycidyl ether)-1,3,5-triazine to chloroplatinic acid is 100:(0.02-0.03).

[0011] Preferably, the preparation method of 2-methylallyloxy-4,6-bis(glycidyl ether)-1,3,5-triazine includes the following steps:

[0012] Step (1): Add cyanuric chloride, dichloromethane, and 2-methylallyl alcohol to a reaction vessel, add sodium hydroxide aqueous solution and tetrabutylammonium bromide dropwise, stir the reaction at 10-15℃ for 10-20 min, add water, let stand to separate the layers, separate the dichloromethane organic phase, dry with anhydrous sodium sulfate to remove water, rotary evaporate, and dry to obtain 2-methylallyloxy-4,6-dichloro-1,3,5-triazine.

[0013] Step (2): Add 2-methylallyloxy-4,6-dichloro-1,3,5-triazine and glycidyl ether to toluene, add sodium hydride, heat to 40-50℃ and stir for 1-1.5h, then heat to 80-90℃ and stir for 2-3h. After filtration, the filtrate is evaporated by rotary evaporation, washed with water, and the product is recrystallized with ethanol to obtain 2-methylallyloxy-4,6-di(glycidyl ether)-1,3,5-triazine.

[0014] The reaction formula is:

[0015]

[0016] Preferably, in step (1), the molar ratio of cyanuric chloride, 2-methylallyl alcohol, sodium hydroxide, and tetrabutylammonium bromide is 1:1:(12-13):(0.1-0.11).

[0017] Preferably, in step (2), the molar ratio of 2-methylallyloxy-4,6-dichloro-1,3,5-triazine, glycidyl ether, and sodium hydride is 1:(2-2.8):(2.6-3).

[0018] The technical advantages of this invention are as follows: Using cyanuric chloride, 2-methylallyl alcohol, and glycidyl ether as reactants, 2-methylallyloxy-4,6-bis(glycidyl ether)-1,3,5-triazine is prepared. This is then reacted with hydrogen-containing silicone oil via an addition reaction to obtain a novel nitrogen-phosphorus-silicon-based triazine sulfonate-based silicone oil flame retardant. This flame retardant is then melt-blended with polycarbonate to obtain a halogen-free flame-retardant PC plastic material. The sulfonate groups in the flame retardant catalyze the crosslinking of polycarbonate into char, while the polysiloxane undergoes pyrolysis, forming a SiC layer on the polycarbonate surface. This layer provides heat insulation, oxygen barrier, and anti-dripping properties, thus providing flame retardant effects. Furthermore, the pyrolysis of the triazine groups produces non-flammable gases such as nitrogen, which helps reduce the oxygen concentration during combustion, thereby improving the limiting oxygen index, UL94 rating, and flame retardant performance of the polycarbonate plastic material.

[0019] The triazine sulfonate-based silicone oil flame retardant of the present invention contains hydroxyl, imino and other groups, which interact with the terminal hydroxyl groups of polycarbonate by forming hydrogen bonds and other interactions, resulting in good compatibility between the flame retardant and polycarbonate. The flame retardant contains a flexible polysiloxane backbone, which plays a good toughening role, thereby improving the bending strength and impact strength of polycarbonate materials. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to its embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the scope of protection of the invention.

[0021] Polycarbonate, Covestro 2405, Shanghai Hehongcheng Plastics Technology Co., Ltd. Hydrogen-containing silicone oil, HS-004, 1.6% hydrogen content, Jiangxi Hongshi New Materials Co., Ltd.

[0022] Example 1

[0023] (1) Add 40 mmol of cyanuric chloride, 150 mL of dichloromethane, and 40 mmol of 2-methylallyl alcohol to a reaction vessel. Add 40 mL of an aqueous solution containing 520 mmol of sodium hydroxide and 4 mmol of tetrabutylammonium bromide. Stir the reaction at 10 °C for 20 min. Add water, allow to stand and separate the layers, and separate the dichloromethane organic phase. Dry with anhydrous sodium sulfate to remove water, then rotary evaporate and dry to obtain 2-methylallyloxy-4,6-dichloro-1,3,5-triazine.

[0024] (2) 30 mmol of 2-methylallyloxy-4,6-dichloro-1,3,5-triazine and 60 mmol of glycidyl ether were added to 70 mL of toluene, and 72 mmol of sodium hydride were added. The mixture was heated to 50 °C and stirred for 1.5 h, then heated to 80 °C and stirred for 3 h. After filtration, the filtrate was evaporated by rotary evaporation, washed with water, and the product was recrystallized from ethanol to obtain 2-methylallyloxy-4,6-di(glycidyl ether)-1,3,5-triazine.

[0025] (3) Toluene solvent, hydrogen-containing silicone oil (hydrogen content 1.6%), 2-methylallyloxy-4,6-di(glycidyl ether)-1,3,5-triazine, and chloroplatinic acid-isopropanol solution with a mass concentration of 0.03 g / mL were added to the reaction vessel. The molar ratio of the SiH group of the hydrogen-containing silicone oil to 2-methylallyloxy-4,6-di(glycidyl ether)-1,3,5-triazine was controlled to be 1:1; the mass ratio of 2-methylallyloxy-4,6-di(glycidyl ether)-1,3,5-triazine to chloroplatinic acid was 100:0.025. Nitrogen gas was introduced, the mixture was heated to 100℃, refluxed for 12 h, rotary evaporated, and dried to obtain glycidyl ether triazine modified silicone oil.

[0026] (4) Add 600 mL of tetrahydrofuran, 30 g of glycidyl ether triazine modified silicone oil and 40 g of sodium 4-aminobenzenesulfonate to a reaction vessel, heat to 40 °C, stir and react for 8 h, evaporate by rotary evaporation, add methanol, filter and dry to obtain triazine sulfonate-based silicone oil flame retardant.

[0027] (5) Mix 1 kg of polycarbonate and 10 g of triazine sulfonate-based silicone oil flame retardant in a torque rheometer at 275°C for 20 min, and discharge the mixture to obtain halogen-free flame-retardant PC plastic material.

[0028] Example 2

[0029] (1) Add 40 mmol of cyanuric chloride, 120 mL of dichloromethane, and 40 mmol of 2-methylallyl alcohol to a reaction vessel. Add 40 mL of an aqueous solution containing 480 mmol of sodium hydroxide and 4.4 mmol of tetrabutylammonium bromide. Stir the reaction at 15 °C for 10 min. Add water, allow to stand and separate the layers, and separate the dichloromethane organic phase. Dry with anhydrous sodium sulfate to remove water, then rotary evaporate and dry to obtain 2-methylallyloxy-4,6-dichloro-1,3,5-triazine.

[0030] (2) 30 mmol of 2-methylallyloxy-4,6-dichloro-1,3,5-triazine and 78 mmol of glycidyl ether were added to 80 mL of toluene, and 90 mmol of sodium hydride were added. The mixture was heated to 40 °C and stirred for 1 h, then heated to 90 °C and stirred for 2 h. After filtration, the filtrate was evaporated by rotary evaporation, washed with water, and the product was recrystallized from ethanol to obtain 2-methylallyloxy-4,6-di(glycidyl ether)-1,3,5-triazine.

[0031] (3) Toluene solvent, hydrogen-containing silicone oil (hydrogen content 1.6%), 2-methylallyloxy-4,6-di(glycidyl ether)-1,3,5-triazine, and chloroplatinic acid-isopropanol solution with a mass concentration of 0.03 g / mL were added to the reaction vessel. The molar ratio of the SiH group of the hydrogen-containing silicone oil to 2-methylallyloxy-4,6-di(glycidyl ether)-1,3,5-triazine was controlled to be 1.2:1; the mass ratio of 2-methylallyloxy-4,6-di(glycidyl ether)-1,3,5-triazine to chloroplatinic acid was controlled to be 100:0.03. Nitrogen gas was introduced, the mixture was heated to 110°C, refluxed for 6 h, rotary evaporated, and dried to obtain glycidyl ether triazine modified silicone oil.

[0032] (4) Add 500 mL of tetrahydrofuran, 30 g of glycidyl ether triazine modified silicone oil and 36 g of sodium 4-aminobenzenesulfonate to a reaction vessel, heat to 50 °C, stir and react for 5 h, evaporate by rotary evaporation, add methanol, filter and dry to obtain triazine sulfonate-based silicone oil flame retardant.

[0033] (5) Mix 1 kg of polycarbonate and 25 g of triazine sulfonate-based silicone oil flame retardant in a torque rheometer at 270°C for 20 min, and discharge the mixture to obtain halogen-free flame-retardant PC plastic material.

[0034] Example 3

[0035] (1) Toluene solvent, hydrogen-containing silicone oil (hydrogen content 1.6%), 2-methylallyloxy-4,6-di(glycidyl ether)-1,3,5-triazine (prepared from Example 1), and chloroplatinic acid-isopropanol solution with a mass concentration of 0.03 g / mL were added to a reaction vessel. The molar ratio of the SiH group of the hydrogen-containing silicone oil to 2-methylallyloxy-4,6-di(glycidyl ether)-1,3,5-triazine was controlled to be 1.1:1; the mass ratio of 2-methylallyloxy-4,6-di(glycidyl ether)-1,3,5-triazine to chloroplatinic acid was 100:0.02. Nitrogen gas was introduced, the mixture was heated to 110°C, refluxed for 10 h, rotary evaporated, and dried to obtain glycidyl ether triazine modified silicone oil.

[0036] (2) Add 600 mL of tetrahydrofuran, 30 g of glycidyl ether triazine modified silicone oil and 45 g of sodium 4-aminobenzenesulfonate to a reaction vessel, heat to 45 °C, stir and react for 8 h, evaporate by rotary evaporation, add methanol, filter and dry to obtain triazine sulfonate-based silicone oil flame retardant.

[0037] (3) Mix 1 kg of polycarbonate and 40 g of triazine sulfonate-based silicone oil flame retardant in a torque rheometer at 280°C for 15 min, and discharge the mixture to obtain halogen-free flame-retardant PC plastic material.

[0038] Example 4

[0039] (1) 1 kg of polycarbonate and 55 g of triazine sulfonate-based silicone oil flame retardant (prepared in Example 1) were mixed in a torque rheometer at 275°C for 20 min and discharged to obtain halogen-free flame-retardant PC plastic material.

[0040] Example 5

[0041] (2) 1 kg of polycarbonate and 70 g of triazine sulfonate-based silicone oil flame retardant (prepared in Example 1) were mixed in a torque rheometer at 275°C for 20 min and discharged to obtain halogen-free flame-retardant PC plastic material.

[0042] Example 6

[0043] (2) 1 kg of polycarbonate and 80 g of triazine sulfonate-based silicone oil flame retardant (prepared in Example 1) were mixed in a torque rheometer at 275°C for 20 min, and the mixture was discharged to obtain halogen-free flame-retardant PC plastic material.

[0044] Comparative Example 1

[0045] (1) 1 kg of polycarbonate was treated in a torque rheometer at 275°C for 20 min, and then discharged to obtain PC plastic material.

[0046] Comparative Example 2

[0047] (1) Mix 1 kg of polycarbonate and 10 g of hydrogen-containing silicone oil (hydrogen content 1.6%) in a torque rheometer at 275°C for 20 min, and then discharge the mixture to obtain PC plastic material.

[0048] Comparative Example 3

[0049] (1) 1 kg of polycarbonate and 10 g of glycidyl ether triazine modified silicone oil (prepared in Example 1) were mixed in a torque rheometer at 275°C for 20 min, and the mixture was discharged to obtain PC plastic material.

[0050] PC plastic material was injection molded into standard specimens at a temperature of 280℃ and a pressure of 60MPa. Vertical burning tests were conducted according to the UL94 method. Oxygen index was tested according to GB / T2406.1-2008. Flexural properties were tested according to GB / T9341-2008. Impact strength was tested according to GB / T1843-2008.

[0051] Table 1: Test Results

[0052]

[0053]

[0054] As shown in Table 1, compared with Comparative Example 1, the polycarbonate in Examples 1-6 contained a triazine sulfonate-based silicone oil flame retardant. This flame retardant uses silicone oil polysiloxane as the main molecular chain, with triazine and sulfonate groups introduced into the side chain to form a sulfonate-based nitrogen-silicon flame retardant. When polycarbonate burns, the sulfonate groups can catalyze the crosslinking of polycarbonate into char, and the polysiloxane undergoes pyrolysis to form a SiC layer on the surface of polycarbonate, which plays a role in heat insulation, oxygen isolation, and flame retardancy such as preventing dripping. In addition, the pyrolysis of the triazine groups produces non-combustible gases such as nitrogen, which helps to reduce the oxygen concentration during combustion, thereby improving the limiting oxygen index and UL94 rating of the polycarbonate plastic material, and exhibiting strong flame retardant properties. Furthermore, the triazine sulfonate-based silicone oil flame retardant contains hydroxyl, imino and other groups, which interact with the terminal hydroxyl groups of polycarbonate by forming hydrogen bonds, thereby improving the compatibility between the flame retardant and polycarbonate. The flame retardant contains a flexible polysiloxane backbone, which can play a good toughening role and is beneficial to improving the bending strength and impact strength of polycarbonate materials.

[0055] Comparative Example 2 only added polysiloxane, which does not contain triazine and sulfonate groups, resulting in poor flame retardant effect. It also does not contain hydroxyl, imino and other groups, resulting in poor compatibility with polycarbonate, poor toughening effect, and low flexural strength and impact strength of polycarbonate.

[0056] Comparative Example 3 was modified with glycidyl ether triazine silicone oil, which does not contain sulfonate groups, resulting in poor flame retardancy. It also does not contain hydroxyl, imino, or other groups, leading to poor compatibility with polycarbonate, poor toughening effect, and low flexural and impact strength of polycarbonate.

[0057] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A process for preparing a halogen-free flame-retardant PC plastic material, characterized in that, The preparation method comprises the following steps: Step A, toluene, hydrogen-containing silicone oil, 2-methyl allyloxy-4,6-di(glycidyl ether)-1,3,5-triazine, chloroplatinic acid-isopropanol solution are added into a reaction container, nitrogen is introduced, heated to 100-110℃, condensation reflux reaction is carried out for 6-12h, rotary evaporation, drying, glycidyl ether triazine modified silicone oil is obtained; Step B, tetrahydrofuran, glycidyl ether triazine-based silicone oil, 4-aminobenzenesulfonic acid sodium is added into a reaction container, after reaction, rotary evaporation is carried out, methanol is added, after filtration, drying is carried out, triazine sulfonate-based silicone oil flame retardant is obtained; Step C, polycarbonate and triazine sulfonate-based silicone oil flame retardant with a mass ratio of 100:(1-8) are blended, the material is discharged, halogen-free flame-retardant PC plastic material is obtained; In step A, the mass ratio of Si-H groups in hydrogen-containing silicone oil and 2-methyl allyloxy-4,6-di(glycidyl ether)-1,3,5-triazine is (1-1.2):1; the mass ratio of 2-methyl allyloxy-4,6-di(glycidyl ether)-1,3,5-triazine and chloroplatinic acid is 100:(0.02-0.03); In step B, the mass ratio of glycidyl ether triazine-based silicone oil and 4-aminobenzenesulfonic acid sodium is 100:(120-150); In step B, the reaction temperature is 40-50℃, and the reaction time is 5-8h.

2. The process for preparing halogen-free flame-retardant PC plastic material according to claim 1, characterized in that, In step C, the blending temperature is 270-280℃, and the time is 15-20min.

3. The process for preparing halogen-free flame-retardant PC plastic material according to claim 1, characterized in that, The preparation method of 2-methyl allyloxy-4,6-di(glycidyl ether)-1,3,5-triazine comprises the following steps: Step (1), cyanuric chloride, dichloromethane, 2-methyl allyl alcohol are added into a reaction container, sodium hydroxide aqueous solution, tetrabutylammonium bromide are added dropwise, stirring is carried out at 10-15℃ for 10-20min, water is added, after standing and separation, dichloromethane organic phase is obtained, dried with anhydrous sodium sulfate, rotary evaporation, drying, 2-methyl allyloxy-4,6-dichloro-1,3,5-triazine is obtained; Step (2), 2-methyl allyloxy-4,6-dichloro-1,3,5-triazine, glycidyl ether are added into toluene, sodium hydride is added, stirring is carried out, after filtration, the filtrate is rotary evaporated, washed with water, the product is recrystallized with ethanol, 2-methyl allyloxy-4,6-di(glycidyl ether)-1,3,5-triazine is obtained.

4. The process for preparing halogen-free flame-retardant PC plastic material according to claim 3, characterized in that, In step (1), the mass ratio of cyanuric chloride, 2-methyl allyl alcohol, sodium hydroxide, tetrabutylammonium bromide is 1:1:(12-13):(0.1-0.11).

5. The process for preparing halogen-free flame-retardant PC plastic material according to claim 3, characterized in that, In step (2), the mass ratio of 2-methyl allyloxy-4,6-dichloro-1,3,5-triazine, glycidyl ether, sodium hydride is 1:(2-2.8):(2.6-3).

6. The process for preparing halogen-free flame-retardant PC plastic material according to claim 3, characterized in that, In step (2), the reaction is first carried out at 40-50℃ for 1-1.5h, and then carried out at 80-90℃ for 2-3h.

7. Halogen-free flame-retardant PC plastic material prepared by the preparation method of any one of claims 1-6.

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