Halogen-free flame-retardant composite plastic and preparation method thereof

Abstract

The present invention relates to the field of plastic technology, and discloses a halogen-free flame-retardant composite plastic and a preparation method thereof. The composite plastic of the present invention comprises the following raw materials in parts by weight: 80-90 parts of polyethylene terephthalate, 15-25 parts of polycarbonate, 8-12 parts of a modified flame retardant, 0.5-1.5 parts of an antioxidant, and 1-3 parts of a lubricant. The composite plastic uses polyethylene terephthalate and polycarbonate as the main plastic matrix, and adds functional additives such as the modified flame retardant, antioxidant, and lubricant to improve the flame retardancy and mechanical properties of the plastic. The modified flame retardant is a composite of an inorganic flame retardant and an organic flame retardant. Compared with traditional flame-retardant plastics that add a single organic flame retardant and an inorganic flame retardant, the composite combines the two, achieving a low-dosage, high-efficiency flame retardant effect.

Description

Technical Field

[0001] The present invention relates to the technical field of plastics, and in particular to a halogen-free flame-retardant composite plastic and a preparation method thereof. Background Art

[0002] With the rapid development of modern industry, plastics are increasingly used in electronics, automotive, home appliances, construction, and other fields. However, the flammability of plastics poses a significant fire risk during use, making the development of flame-retardant plastics a key research area in materials science. Traditional flame-retardant plastics mostly use halogen-containing flame retardants. While these flame retardants are highly effective in preventing flames in plastics, they produce large amounts of toxic fumes and corrosive gases during combustion, posing serious risks to the environment and human health. Compared to halogen-containing flame retardants, halogen-free flame retardants do not release toxic gases and corrosive substances, offering improved environmental performance and safety.

[0003] Despite their significant environmental advantages, halogen-free flame-retardant plastics still face several technical challenges in practical application. First, the flame retardant efficiency of halogen-free flame retardants is relatively low, typically requiring a high addition level to achieve the desired flame retardant effect. This can adversely affect the mechanical and processing properties of the plastic. Second, some halogen-free flame retardants are prone to precipitation during processing, leading to mold contamination and reduced production efficiency. Therefore, to address the current challenges with halogen-free flame retardants, researchers can develop new halogen-free flame retardants or composite flame retardants to meet practical application needs. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a halogen-free flame-retardant composite plastic and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A halogen-free flame-retardant composite plastic comprises the following raw materials in parts by weight: 80-90 parts of polyethylene terephthalate, 15-25 parts of polycarbonate, 8-12 parts of a modified flame retardant, 0.5-1.5 parts of an antioxidant, and 1-3 parts of a lubricant;

[0007] The antioxidant is one of antioxidant 1010 or antioxidant 168;

[0008] The lubricant is one of calcium stearate or zinc stearate;

[0009] The modified flame retardant is prepared by the following steps:

[0010] Step A1: 1-vinylimidazole, 2-mercaptoethanol, and benzoin dimethyl ether were mixed uniformly, and the mixture was irradiated under 100 W, 365 nm ultraviolet light for 15-25 min. n-hexane was added, stirred for 20 min, and rotary evaporated to obtain an imidazole derivative.

[0011] Furthermore, in step A1, the usage ratio of 1-vinylimidazole, 2-mercaptoethanol, benzoin dimethyl ether and n-hexane is 0.1-0.2 mol: 0.1-0.2 mol: 0.04-0.08 g: 50 mL;

[0012] Step A2, mixing an imidazole derivative and phenylphosphonothioyl dichloride, introducing nitrogen and heating to 80-90° C. for reaction for 1 hour, then heating to 130-140° C. for reaction for 8 hours, and then heating to 160° C. for reaction for 1 hour, extracting, filtering, and drying to collect the organic flame retardant; then mixing the organic flame retardant, the composite auxiliary agent, and deionized water for 2 hours, filtering, washing, and drying to obtain a modified flame retardant;

[0013] Furthermore, in step A2, the molar ratio of the imidazole derivative to phenylphosphonothioate dichloride in the organic flame retardant is 2:1;

[0014] Furthermore, in step A2, the mass ratio of the organic flame retardant, the composite auxiliary agent and deionized water in the modified flame retardant is 2-6:1-3:20.

[0015] The composite auxiliary agent is prepared by the following steps:

[0016] Step B1, dispersing cerium chloride heptahydrate and sodium phosphate dodecahydrate in deionized water, respectively, to obtain a cerium chloride solution and a sodium phosphate solution; mixing the sodium phosphate solution and the cerium chloride solution, vigorously stirring at room temperature for 15 minutes, adjusting the pH to 1, and then hydrothermally reacting at 170° C. for 12 hours, centrifuging, washing, and drying to obtain a CePO4 nanomaterial;

[0017] Furthermore, in step B1, the pH is adjusted to pH=1 using a 25wt% hydrochloric acid solution;

[0018] Furthermore, in step B1, the ratio of cerium chloride heptahydrate to deionized water in the cerium chloride solution is 1.12-3.36 g:15 mL, and the ratio of sodium phosphate dodecahydrate to deionized water in the sodium phosphate solution is 1.14-3.42 g:15 mL;

[0019] Furthermore, in step B1, the hydrothermal reaction is carried out in an autoclave;

[0020] Step B2, CePO4 nanomaterial, cationic polyacrylamide (CPAM) and deionized water were mixed and stirred for 2 hours, then ultrasonically treated for 48 hours, centrifuged, washed and dried to obtain CPAM-CePO4 nanomaterial;

[0021] Furthermore, in step B2, the usage ratio of CePO4 nanomaterial, CPAM and deionized water is 1-2 g:2-6 g:20 mL;

[0022] Step B3, mixing boron nitride powder and deionized water, adjusting the pH, and then ultrasonically treating for 20-30 hours, centrifuging, washing, and drying to obtain hydroxylated boron nitride; mixing CPAM-CePO4 nanomaterial, hydroxylated boron nitride, and deionized water, and ultrasonically treating for 48 hours, centrifuging, washing, and drying to obtain a composite auxiliary agent;

[0023] Furthermore, in step B3, the mass ratio of boron nitride powder and deionized water in the hydroxylated boron nitride is 1:1, and the mass ratio of CPAM-CePO4 nanomaterial, hydroxylated boron nitride and deionized water in the composite additive is 1:1:10;

[0024] Furthermore, in step B3, the pH is adjusted to 12-13 using 10 wt % sodium hydroxide solution.

[0025] A method for preparing a halogen-free flame-retardant composite plastic comprises the following steps:

[0026] Raw materials are weighed according to weight, polyethylene terephthalate, polycarbonate, modified flame retardant, antioxidant and lubricant are mixed and stirred evenly, and then transferred to a twin-screw extruder for melt extrusion, and then cooled, granulated and dried to obtain a halogen-free flame retardant composite plastic.

[0027] Beneficial effects of the present invention:

[0028] The composite plastic in the present invention is based on polyethylene terephthalate and polycarbonate as the main plastic matrix, and functional additives such as modified flame retardants, antioxidants and lubricants are added to improve the flame retardant properties and mechanical properties of the plastic; among them, the modified flame retardant is a composite of inorganic flame retardants and organic flame retardants. Compared with the halogen flame retardants added to traditional flame retardant plastics, the composite combines the two and has the effect of low dosage, non-toxicity and high efficiency flame retardancy.

[0029] The modified flame retardant described in this application is a composite of an inorganic and organic flame retardant. Its introduction into composite plastics significantly improves the flame retardancy of the plastic matrix. The composite additive, acting as an inorganic filler flame retardant within the plastic matrix, utilizes the electrostatic interaction between boron nitride and CPAM-CePO4 nanomaterials. Boron nitride forms a protective ceramic layer during the plastic combustion process, blocking oxygen and heat, thereby preventing the spread of flames. The CePO4 composite not only uses its rare earth element (cerium) to capture free radicals generated by combustion but also utilizes the decomposition products of phosphorus to promote carbonization within the polymer matrix, forming a dense carbon layer. The organic flame retardant incorporates an imidazole structure, phosphorus, and sulfur, which synergistically enhance the flame retardancy of the matrix. The imidazole structure absorbs heat through a chemical reaction, dissipating the energy of the igniting substance, reducing the heat released during combustion and slowing the combustion process. The sulfur inhibits pyrolysis, preventing premature and violent decomposition of the plastic. It also combines with oxygen to slow the spread of flames. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] Example 1: The composite auxiliary agent is prepared by the following steps:

[0032] Step B1, 1.12 g of cerium chloride heptahydrate and 1.14 g of sodium phosphate dodecahydrate were dispersed in 15 mL of deionized water, respectively, and recorded as cerium chloride solution and sodium phosphate solution; the sodium phosphate solution and the cerium chloride solution were mixed, vigorously stirred at room temperature for 15 minutes, and the pH was adjusted to 1 with 25 wt% hydrochloric acid solution, and then hydrothermally reacted at 170 ° C in an autoclave for 12 hours, centrifuged, washed, and dried to obtain CePO4 nanomaterials;

[0033] Step B2: 1 g of CePO4 nanomaterial, 2 g of cationic polyacrylamide and 20 mL of deionized water were mixed and stirred for 2 h, and then ultrasonically treated for 48 h, centrifuged, washed and dried to obtain CPAM-CePO4 nanomaterial;

[0034] Step B3: 10 g of boron nitride powder and 10 g of deionized water were mixed evenly, and the pH was adjusted to 12 with 10 wt% sodium hydroxide solution, and then ultrasonically treated for 20 h, centrifuged, washed, and dried to obtain hydroxylated boron nitride; 3 g of CPAM-CePO4 nanomaterial, 3 g of hydroxylated boron nitride, and 30 g of deionized water were mixed and ultrasonically treated for 48 h, centrifuged, washed, and dried to obtain a composite auxiliary agent.

[0035] The modified flame retardant is prepared by the following steps:

[0036] Step A1: 0.1 mol of 1-vinylimidazole, 0.1 mol of 2-mercaptoethanol, and 0.04 g of benzoin dimethyl ether were mixed uniformly, and the mixture was irradiated under 100 W, 365 nm ultraviolet light for 15 min. 50 mL of n-hexane was added, stirred for 20 min, and rotary evaporated to obtain an imidazole derivative.

[0037] Step A2, 0.2 mol of imidazole derivative and 0.1 mol of phenylphosphonothioate dichloride were mixed, nitrogen was introduced and the temperature was raised to 80 ° C for reaction for 1 hour, then the temperature was raised to 130 ° C for reaction for 8 hours, and then the temperature was raised to 160 ° C for reaction for 1 hour, extracted, filtered, and dried to collect the organic flame retardant; then 2 g of the organic flame retardant, 1 g of the composite auxiliary agent and 20 g of deionized water were mixed and stirred for 2 hours, filtered, washed, and dried to obtain the modified flame retardant.

[0038] Example 2: The composite auxiliary agent is prepared by the following steps:

[0039] Step B1, 2.24 g of cerium chloride heptahydrate and 2.28 g of sodium phosphate dodecahydrate were dispersed in 15 mL of deionized water, respectively, and recorded as cerium chloride solution and sodium phosphate solution; the sodium phosphate solution and the cerium chloride solution were mixed, vigorously stirred at room temperature for 15 minutes, and the pH was adjusted to 1 with 25 wt% hydrochloric acid solution, and then hydrothermally reacted at 170 ° C in an autoclave for 12 hours, centrifuged, washed, and dried to obtain CePO4 nanomaterials;

[0040] Step B2, 1.5 g of CePO4 nanomaterial, 4 g of cationic polyacrylamide and 20 mL of deionized water were mixed and stirred for 2 h, then ultrasonically treated for 48 h, centrifuged, washed and dried to obtain CPAM-CePO4 nanomaterial;

[0041] Step B3: 10 g of boron nitride powder and 10 g of deionized water were mixed evenly, and the pH was adjusted to 12.5 with 10 wt% sodium hydroxide solution, and then ultrasonically treated for 25 h, centrifuged, washed, and dried to obtain hydroxylated boron nitride; 3 g of CPAM-CePO4 nanomaterial, 3 g of hydroxylated boron nitride, and 30 g of deionized water were mixed and ultrasonically treated for 48 h, centrifuged, washed, and dried to obtain a composite auxiliary agent.

[0042] The modified flame retardant is prepared by the following steps:

[0043] Step A1: 0.15 mol of 1-vinylimidazole, 0.15 mol of 2-mercaptoethanol, and 0.06 g of benzoin dimethyl ether were mixed uniformly, and the mixture was irradiated under 100 W, 365 nm ultraviolet light for 20 min. 50 mL of n-hexane was added, stirred for 20 min, and rotary evaporated to obtain an imidazole derivative.

[0044] Step A2, 0.2 mol of imidazole derivative and 0.1 mol of phenylphosphonothioate dichloride were mixed, nitrogen was introduced and the temperature was raised to 85 ° C for reaction for 1 hour, then the temperature was raised to 135 ° C for reaction for 8 hours, and then the temperature was raised to 160 ° C for reaction for 1 hour, extracted, filtered, and dried to collect the organic flame retardant; then 4 g of the organic flame retardant, 2 g of the composite auxiliary agent and 20 g of deionized water were mixed and stirred for 2 hours, filtered, washed, and dried to obtain the modified flame retardant.

[0045] Example 3: The composite auxiliary agent is prepared by the following steps:

[0046] Step B1, 3.36g of cerium chloride heptahydrate and 3.42g of sodium phosphate dodecahydrate were dispersed in 15mL of deionized water, respectively, and recorded as cerium chloride solution and sodium phosphate solution; the sodium phosphate solution and the cerium chloride solution were mixed, vigorously stirred at room temperature for 15min, and adjusted to pH=1 with 25wt% hydrochloric acid solution, and then hydrothermally reacted in an autoclave at 170°C for 12h, centrifuged, washed, and dried to obtain CePO4 nanomaterial;

[0047] Step B2, 2 g of CePO4 nanomaterial, 6 g of cationic polyacrylamide and 20 mL of deionized water were mixed and stirred for 2 h, then ultrasonically treated for 48 h, centrifuged, washed and dried to obtain CPAM-CePO4 nanomaterial;

[0048] Step B3: 10 g of boron nitride powder and 10 g of deionized water were mixed evenly, and the pH was adjusted to 13 with 10 wt% sodium hydroxide solution, and then ultrasonically treated for 30 h, centrifuged, washed, and dried to obtain hydroxylated boron nitride; 3 g of CPAM-CePO4 nanomaterial, 3 g of hydroxylated boron nitride, and 30 g of deionized water were mixed and ultrasonically treated for 48 h, centrifuged, washed, and dried to obtain a composite auxiliary agent.

[0049] The modified flame retardant is prepared by the following steps:

[0050] Step A1: 0.2 mol of 1-vinylimidazole, 0.2 mol of 2-mercaptoethanol, and 0.08 g of benzoin dimethyl ether were mixed uniformly, and the mixture was irradiated under 100 W, 365 nm ultraviolet light for 25 min. 50 mL of n-hexane was added, stirred for 20 min, and rotary evaporated to obtain an imidazole derivative.

[0051] Step A2, 0.2 mol of imidazole derivative and 0.1 mol of phenylphosphonothioate dichloride were mixed, nitrogen was introduced and the temperature was raised to 90 ° C for reaction for 1 hour, then the temperature was raised to 140 ° C for reaction for 8 hours, and then the temperature was raised to 160 ° C for reaction for 1 hour, extracted, filtered, and dried to collect the organic flame retardant; then 6 g of the organic flame retardant, 3 g of the composite additive and 20 g of deionized water were mixed and stirred for 2 hours, filtered, washed, and dried to obtain the modified flame retardant.

[0052] Example 4: A method for preparing a halogen-free flame-retardant composite plastic comprises the following steps:

[0053] The raw materials were weighed by weight, and 80 parts of polyethylene terephthalate, 15 parts of polycarbonate, 8 parts of the modified flame retardant prepared in Example 1, 0.5 parts of antioxidant 1010 and 1 part of calcium stearate were mixed and stirred evenly. The mixture was then transferred to a twin-screw extruder for melt extrusion, and then cooled, granulated and dried to obtain a halogen-free flame-retardant composite plastic.

[0054] Example 5: A method for preparing a halogen-free flame-retardant composite plastic comprises the following steps:

[0055] The raw materials were weighed by weight, and 85 parts of polyethylene terephthalate, 20 parts of polycarbonate, 10 parts of the modified flame retardant prepared in Example 2, 1 part of antioxidant 168 and 2 parts of zinc stearate were mixed and stirred evenly. The mixture was then transferred to a twin-screw extruder for melt extrusion, and then cooled, granulated and dried to obtain a halogen-free flame-retardant composite plastic.

[0056] Example 6: A method for preparing a halogen-free flame-retardant composite plastic comprises the following steps:

[0057] The raw materials were weighed by weight, and 90 parts of polyethylene terephthalate, 25 parts of polycarbonate, 12 parts of the modified flame retardant prepared in Example 3, 1.5 parts of antioxidant 1010 and 3 parts of zinc stearate were mixed and stirred evenly. The mixture was then transferred to a twin-screw extruder for melt extrusion, and then cooled, granulated and dried to obtain a halogen-free flame-retardant composite plastic.

[0058] Comparative Example 1: This comparative example is a flame-retardant composite plastic. The difference from Example 6 is that magnesium hydroxide is used instead of the modified flame retardant prepared in Example 3. The rest are the same.

[0059] Comparative Example 2: This comparative example is a flame-retardant composite plastic. The difference from Example 6 is that the composite auxiliary agent prepared in Example 3 is used instead of the modified flame retardant prepared in Example 3, and the rest are the same.

[0060] Comparative Example 3: This comparative example is a flame-retardant composite plastic. The difference from Example 6 is that the organic flame retardant prepared in Example 3 is used instead of the modified flame retardant prepared in Example 3, and the rest are the same.

[0061] The flame retardant composite plastics prepared in Examples 4-6 and Comparative Examples 1-3 were subjected to performance tests:

[0062] Flame retardant performance test: Limiting oxygen index test is carried out according to GB / T 2406.2-2009 standard, and vertical burning test is carried out according to GB / T2408-2008;

[0063] Tensile strength test: tensile strength test is carried out according to GB / T 1040-2006 standard;

[0064] The test results are shown in Table 1:

[0065] Table 1: Performance test results

[0066]

[0067] As can be seen from Table 1, after the limiting oxygen index and flame retardancy tests of the composite plastic prepared by the present invention, the limiting oxygen index is (31.3-32.1)%, the combustion grade is V-0, and it shows that the composite plastic has excellent flame retardancy; after the tensile strength test, the tensile strength is (76.5-78.1) MPa, indicating that the composite plastic has good mechanical properties.

[0068] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the scope defined by the concept of the invention, they should all fall within the scope of protection of the present invention.

Claims

1. A halogen-free flame-retardant composite plastic, characterized in that: The invention comprises the following raw materials in parts by weight: 80-90 parts of polyethylene terephthalate, 15-25 parts of polycarbonate, 8-12 parts of modified flame retardant, 0.5-1.5 parts of antioxidant, and 1-3 parts of lubricant; The antioxidant is one of antioxidant 1010 or antioxidant 168; The lubricant is one of calcium stearate or zinc stearate; The modified flame retardant is specifically prepared by the following steps: Step A1: 1-vinylimidazole, 2-mercaptoethanol, and benzoin dimethyl ether were mixed uniformly, and the mixture was irradiated under 100 W, 365 nm ultraviolet light for 15-25 min. n-hexane was added, stirred for 20 min, and rotary evaporated to obtain an imidazole derivative. Step A2, mixing an imidazole derivative and phenylphosphonothioyl dichloride, introducing nitrogen and heating to 80-90° C. for reaction for 1 hour, then heating to 130-140° C. for reaction for 8 hours, and then heating to 160° C. for reaction for 1 hour, extracting, filtering, and drying to collect the organic flame retardant; then mixing the organic flame retardant, the composite auxiliary agent, and deionized water for 2 hours, filtering, washing, and drying to obtain a modified flame retardant; The composite auxiliary agent is specifically prepared by the following steps: Step B1, dispersing cerium chloride heptahydrate and sodium phosphate dodecahydrate in deionized water, respectively, to obtain a cerium chloride solution and a sodium phosphate solution; mixing the sodium phosphate solution and the cerium chloride solution, vigorously stirring at room temperature for 15 minutes, adjusting the pH to 1, and then hydrothermally reacting at 170° C. for 12 hours, centrifuging, washing, and drying to obtain a CePO4 nanomaterial; Step B2, mixing CePO4 nanomaterial, cationic polyacrylamide and deionized water for 2 hours, then ultrasonically treating for 48 hours, centrifuging, washing and drying to obtain CPAM-CePO4 nanomaterial; Step B3: Mix the boron nitride powder and deionized water evenly, adjust the pH, and then ultrasonically treat for 20-30 hours, centrifuge, wash, and dry to obtain hydroxylated boron nitride; mix the CPAM-CePO4 nanomaterial, hydroxylated boron nitride, and deionized water, and ultrasonically treat for 48 hours, centrifuge, wash, and dry to obtain a composite auxiliary agent.

2. The halogen-free flame-retardant composite plastic according to claim 1, characterized in that: In step A1, the usage ratio of 1-vinylimidazole, 2-mercaptoethanol, benzoin dimethyl ether and n-hexane is 0.1-0.2 mol: 0.1-0.2 mol: 0.04-0.08 g: 50 mL.

3. The halogen-free flame-retardant composite plastic according to claim 1, characterized in that: In step A2, the molar ratio of the imidazole derivative to phenylphosphonothioyl dichloride in the organic flame retardant is 2:1, and the mass ratio of the organic flame retardant, the composite auxiliary agent and deionized water in the modified flame retardant is 2-6:1-3:

20.

4. The halogen-free flame-retardant composite plastic according to claim 1, characterized in that: In step B1, the ratio of cerium chloride heptahydrate to deionized water in the cerium chloride solution is 1.12-3.36 g:15 mL, and the ratio of sodium phosphate dodecahydrate to deionized water in the sodium phosphate solution is 1.14-3.42 g:15 mL.

5. The halogen-free flame-retardant composite plastic according to claim 1, characterized in that: In step B2, the usage ratio of CePO4 nanomaterial, CPAM and deionized water is 1-2g:2-6g:20mL.

6. The halogen-free flame-retardant composite plastic according to claim 1, characterized in that: In step B3, the mass ratio of boron nitride powder to deionized water in the hydroxylated boron nitride is 1:1, and the mass ratio of CPAM-CePO4 nanomaterial, hydroxylated boron nitride and deionized water in the composite additive is 1:1:

10.

7. The halogen-free flame-retardant composite plastic according to claim 1, characterized in that: In step B3, the pH is adjusted to 12-13 using 10 wt % sodium hydroxide solution.

8. A method for preparing the halogen-free flame-retardant composite plastic according to any one of claims 1 to 7, characterized in that: The following steps are involved: Raw materials are weighed according to weight, polyethylene terephthalate, polycarbonate, modified flame retardant, antioxidant and lubricant are mixed and stirred evenly, and then transferred to a twin-screw extruder for melt extrusion, and then cooled, granulated and dried to obtain a halogen-free flame retardant composite plastic.

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