Anti-dripping flame-retardant PP master batch, preparation method and application thereof
By forming covalent bonds between PP-g-GMA modified halogen-free intumescent flame retardant and anti-dripping agent and PP matrix, the flame retardancy and anti-dripping properties of PP materials are solved, achieving efficient and stable flame retardant effect and excellent mechanical properties.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DONGGUAN CZY CHEM CO LTD
- Filing Date
- 2025-10-20
- Publication Date
- 2026-05-22
AI Technical Summary
Existing PP materials have insufficient flame retardancy, are easily combustible and melt and drip, and traditional flame retardants have poor compatibility with the matrix, affecting mechanical properties and long-term stability.
PP-g-GMA was used to modify the surface of halogen-free intumescent flame retardant and anti-dripping agent. Covalent bonds were formed between silicate ester and aminosilane coupling agent to enhance compatibility. Grafting reaction was carried out with PP matrix to form a strong molecular bridge, thereby improving flame retardant efficiency and anti-dripping properties.
It achieves a highly efficient flame retardant effect, improves the impact strength and toughness of the material, and ensures the uniform dispersion and long-term stability of the flame retardant in the matrix, avoiding melting and dripping.
Smart Images
Figure CN121136271B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of PP masterbatch materials, specifically to an anti-dripping flame-retardant PP masterbatch, its preparation method, and its application. Background Technology
[0002] Polypropylene (PP) is widely used due to its excellent overall properties, but its limiting oxygen index (LOI) is low (only 17-18%), making it extremely flammable. When burning, it produces severe molten dripping, posing a significant safety hazard of igniting other items and causing the fire to spread. This severely limits its application in fields with high safety requirements, such as automobiles, home appliances, and electronics.
[0003] To improve the flame retardancy of polypropylene (PP), halogen-free intumescent flame retardants (IFR) have become the mainstream choice. However, existing IFR systems typically face multiple challenges in application: First, to achieve the ideal flame retardant effect (such as UL94 V-0 rating), the addition amount often needs to be as high as 25%-30% or more, which significantly degrades the mechanical properties of the material, especially impact strength; second, the flame retardant has poor compatibility with the non-polar PP matrix, easily leading to uneven dispersion and weak interfacial bonding, which in turn causes the flame retardant to migrate and precipitate ("frosting"), affecting the product's appearance and long-term flame retardant stability; third, many flame retardant systems are unable to effectively suppress the melt dripping of PP. Polytetrafluoroethylene (PTFE) is a highly efficient anti-dripping agent that can form a fibrous network structure at high temperatures, preventing the polymer melt from flowing. However, how to effectively compound flame retardants with PTFE to achieve efficient anti-dripping while ensuring high flame retardant efficiency (reaching UL94 V-0 rating) and without excessively sacrificing the material's mechanical properties is a technical problem that urgently needs to be solved in this field.
[0004] Patent CN 115216089 B synthesizes a novel intumescent DOPO flame retardant with a synergistic N and P flame-retardant effect, enabling polyolefins to exhibit excellent flame-retardant properties even at low addition levels. Simultaneously, the addition of certain amounts of linear low-density polyethylene, silane coupling agent-modified glass fiber, and nano-calcium carbonate improves the mechanical properties of polypropylene, particularly significantly enhancing its impact resistance. Patent CN 111187470 B prepares a highly efficient flame-retardant polypropylene masterbatch containing both aliphatic and aromatic bromine, achieving excellent flame-retardant effects with minimal dosage in the material. Summary of the Invention
[0005] In view of the shortcomings and deficiencies of the existing technology, the primary objective of this invention is to provide a drip-resistant flame-retardant PP masterbatch with high flame retardant efficiency, significant anti-dripping effect, and minimal impact on matrix properties.
[0006] Another object of the present invention is to provide a drip-resistant flame-retardant PP masterbatch prepared by the above method.
[0007] Another object of the present invention is to provide the application of the above-mentioned anti-drip flame-retardant PP masterbatch in PP sheets.
[0008] The objective of this invention is achieved through the following technical solution:
[0009] A method for preparing an anti-drip flame-retardant PP masterbatch includes the following preparation steps:
[0010] (1) Glycidyl methacrylate-grafted polypropylene (PP-g-GMA) was added to a solvent and heated to dissolve evenly. Then, a halogen-free intumescent flame retardant and an anti-dripping agent were added and stirred to disperse evenly to obtain a mixture. Next, silicate ester, aminosilane coupling agent, and ammonia were added dropwise to the mixture and stirred to react. After the reaction was complete, the solvent was removed by vacuum drying to obtain a surface-coated modified anti-dripping flame retardant. The reaction equation is as follows: Figure 1 As shown:
[0011] In the alkaline environment provided by ammonia, the added silicate ester and aminosilane undergo hydrolysis due to the attack of water molecules on their alkoxy groups (-OR), generating highly reactive silanols. The amino group at one end of the hydrolyzed aminosilane molecule... It will nucleophilically attack the epoxy groups on the PP-g-GMA molecular chain, undergo a ring-opening reaction, and form a strong covalent bond. The silanols generated by hydrolysis, as well as the polar groups (such as P=O, -OH, etc.) on the surface of flame retardants and anti-dripping agents (pentaerythritol phosphate melamine salt and SN3300), are adsorbed through hydrogen bonds and van der Waals forces and undergo condensation reactions.
[0012] (2) The surface-coated modified anti-drip flame retardant obtained in step (1) is melt-mixed with PP, refractory filler, antioxidant and lubricant and extruded into granules by a high-torque twin-screw extruder to obtain anti-drip flame retardant PP masterbatch.
[0013] Further, the solvent mentioned in step (1) is dimethylformamide (DMF), dimethyl sulfoxide (DMSO) or N-methylpyrrolidone (NMP).
[0014] Further, the halogen-free intumescent flame retardant mentioned in step (1) is at least one of melamine polyphosphate, pentaerythritol phosphate dicyandiamide salt, and pentaerythritol phosphate melamine salt, and the amount of halogen-free intumescent flame retardant added is 1 to 4 times that of PP-g-GMA.
[0015] Further, the anti-dripping agent in step (1) is at least one of polytetrafluoroethylene concentrated masterbatch SN3300 and FD3200, and the amount of anti-dripping agent added is 1% to 5% of PP-g-GMA.
[0016] Further, the silicate ester in step (1) is tetraethyl orthosilicate, and the amount of tetraethyl orthosilicate added is 50% to 100% of the mass of PP-g-GMA;
[0017] Further, the aminosilane coupling agent in step (1) is 3-aminopropyltriethoxysilane, and the amount of 3-aminopropyltriethoxysilane added is 20% to 60% of the mass of PP-g-GMA.
[0018] Furthermore, the amount of ammonia added in step (1) is 40% to 60% of the mass of the silicate ester;
[0019] Furthermore, the stirring reaction temperature in step (1) is controlled at 50~80℃, and the stirring reaction time is 1~5h.
[0020] Further, in step (2), 60-85 parts of polypropylene, 10-20 parts of surface-coated modified anti-drip flame retardant, 1-5 parts of refractory filler, 1-5 parts of antioxidant, and 1-5 parts of lubricant are selected by weight.
[0021] Furthermore, the refractory filler mentioned in step (2) is at least one of talc, kaolin, and nano-montmorillonite.
[0022] Further, the antioxidant mentioned in step (2) is at least one of antioxidant 1010 (pentaerythritol ester), antioxidant 1076 (octadecyl propionate), antioxidant 168 (tris(2,4-di-tert-butylphenyl)phosphite), antioxidant 702 (4,4'-methylenebis(2,6-di-tert-butylphenol)), and antioxidant 300 (2,4,6-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)trimethylbenzene).
[0023] Further, the lubricant mentioned in step (2) is at least one of polyethylene wax and vinyl bis-stearamide.
[0024] Furthermore, in step (2), the feeding port of the high-torque twin-screw extruder adopts a tumbling mixing process; the mixed material is fed into the high-torque twin-screw extruder through a double-cone forced feeder, and the feeding speed of the double-cone forced feeder is 20-40Hz; the extrusion temperature of the high-torque twin-screw extruder is 180-220℃, the main machine speed is 300-500rpm; and the sieve mesh size is 100-200 mesh.
[0025] Compared with the prior art, the beneficial effects of the present invention are:
[0026] (1) This invention pre-modifies the surface of halogen-free intumescent flame retardant and anti-dripping agent using PP-g-GMA, achieving a leap from "physical blending" to "chemical bonding". PP-g-GMA, as a highly efficient reactive compatibilizer, has good compatibility between its polypropylene segments and the PP matrix, while its epoxy groups can undergo ring-opening reactions with the active groups on the surface of the halogen-free intumescent flame retardant to form strong covalent bonds. This effect is like building a strong "molecular bridge" between the polar flame retardant and the non-polar PP matrix, fundamentally solving the problems of poor interfacial compatibility and easy migration and precipitation of flame retardants (blooming) in traditional processes. It not only significantly improves the impact strength and toughness of flame-retardant composite materials, unifying high flame retardancy and excellent mechanical properties, but also ensures the long-term stability of the flame retardant effect. At the same time, the modified flame retardant is more uniformly dispersed in the matrix, which helps to form a denser and more efficient intumescent char layer, thereby synergistically improving the flame retardant efficiency.
[0027] (2) The present invention uses silicate ester and 3-aminopropyltriethoxysilane coupling agent to perform composite coating modification on halogen-free intumescent flame retardant and anti-dripping agent. On the one hand, it can synergistically enhance the bonding force between PP-g-GMA and halogen-free intumescent flame retardant and anti-dripping agent; on the other hand, the addition of 3-aminopropyltriethoxysilane coupling agent can introduce reactive amino groups on the surface of halogen-free intumescent flame retardant and anti-dripping agent, and further perform grafting reaction with PP substrate in the subsequent melt mixing extrusion granulation stage, which can further significantly improve the bonding force between halogen-free intumescent flame retardant and anti-dripping agent and PP substrate. Attached Figure Description
[0028] Figure 1 This is a diagram illustrating the preparation mechanism of the surface-coated modified anti-dripping flame retardant in this invention. Detailed Implementation
[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with existing known technologies. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.
[0030] Example 1
[0031] (1) 10g of PP-g-GMA was added to 100g of NMP solvent and heated to 75℃ with stirring until dissolved. Then, 20g of pentaerythritol phosphate melamine salt and 1g of SN3300 were added and stirred until evenly dispersed to obtain a mixture. Then, 8g of tetraethyl orthosilicate, 4g of 3-aminopropyltriethoxysilane and 4g of ammonia water were added dropwise to the mixture and stirred for 2h. The system temperature was controlled at 70-75℃ during the reaction. After the reaction was completed, the solvent was removed by spray drying to obtain a surface-coated modified anti-dripping flame retardant.
[0032] (2) Add 75g of polypropylene, 2.5g of octadecyl propionate and 2.5g of vinyl bis-stearamide to a high-speed mixer at 800 rpm, stir for 3 min, then add 15g of the surface-coated modified anti-dripping flame retardant and 5g of nano-montmorillonite obtained in step (2), and stir for 10 min at 400 rpm to obtain a mixed material. Extrude and granulate the mixture using a high-torque twin-screw extruder. The feed port adopts a tumbling mixing process. The mixed material is fed into the high-torque twin-screw extruder through a double-cone forced feeder at a feed speed of 30 Hz and a double-cone speed of 12 r / min. Pass the mixture through a 170-mesh sieve to obtain anti-dripping flame retardant PP masterbatch.
[0033] Example 2
[0034] (1) Add 10g of PP-g-GMA to 100g of NMP solvent, heat to 75℃ and stir to dissolve evenly. Then add 20g of pentaerythritol phosphate melamine salt and 1g of SN3300 and stir to disperse evenly to obtain a mixture. Then add 10g of tetraethyl orthosilicate, 2g of 3-aminopropyltriethoxysilane and 4g of ammonia water dropwise to the mixture and stir to react for 3h. The temperature of the system is controlled at 70-75℃ during the reaction. After the reaction is completed, spray dry to remove the solvent to obtain a surface-coated modified anti-dripping flame retardant.
[0035] (2) Add 70g of polypropylene, 2.5g of octadecyl propionate and 2.5g of vinyl bis-stearamide to a high-speed mixer at 800rpm and stir for 3min. Then add 20g of the surface-coated modified anti-dripping flame retardant and 5g of nano-montmorillonite obtained in step (2) and stir for 10min at 400rpm in the high-speed mixer to obtain a mixed material. Extrude and granulate the mixture using a high-torque twin-screw extruder. The feed port adopts a tumbling mixing process. The mixed material is fed into the high-torque twin-screw extruder through a double-cone forced feeder at a feed speed of 30Hz and a double-cone speed of 12r / min. Pass the mixture through a 170-mesh sieve to obtain anti-dripping flame retardant PP masterbatch.
[0036] Comparative Example 1
[0037] A comparative example of an anti-dripping flame-retardant PP masterbatch, which, compared to Example 1, does not contain PP-g-GMA but is otherwise identical, is prepared using the following method:
[0038] (1) Add 20g of pentaerythritol phosphate melamine salt and 5g of SN3300 to 100g of NMP solvent, heat to 75℃ and stir to disperse evenly to obtain a mixture. Then add 8g of tetraethyl orthosilicate, 4g of 3-aminopropyltriethoxysilane and 4g of ammonia water dropwise to the mixture and stir to react for 3h. The temperature of the system is controlled at 70-75℃ during the reaction. After the reaction is completed, spray dry to remove the solvent to obtain a surface-coated modified anti-dripping flame retardant.
[0039] Step (2) is the same as in Example 1.
[0040] Comparative Example 2
[0041] This comparative example is an anti-drip flame-retardant PP masterbatch. Compared with Example 1, PP-g-GMA is added in step (2). The specific preparation method is as follows:
[0042] (1) Add 20g of pentaerythritol phosphate melamine salt and 5g of SN3300 to 100g of NMP solvent, heat to 75℃ and stir to disperse evenly to obtain a mixture. Then add 8g of tetraethyl orthosilicate, 4g of 3-aminopropyltriethoxysilane and 4g of ammonia water dropwise to the mixture and stir to react for 3h. The temperature of the system is controlled at 70-75℃ during the reaction. After the reaction is completed, spray dry to remove the solvent to obtain a surface-coated modified anti-dripping flame retardant.
[0043] (2) Add 65g of polypropylene, 10g of PP-g-GMA, 2.5g of octadecyl propionate and 2.5g of vinyl bis-stearamide to a high-speed mixer at 800 rpm, stir for 3 min, then add 15g of the surface-coated modified anti-dripping flame retardant and 5g of nano-montmorillonite obtained in step (2), and stir for 10 min at 400 rpm to obtain a mixed material. Extrude and granulate the mixture using a high-torque twin-screw extruder. The discharge port adopts a tumbling mixing process. The mixed material is fed into the high-torque twin-screw extruder through a double-cone forced feeder at a feeding speed of 30 Hz and a double-cone speed of 12 r / min. Pass the mixture through a 170-mesh sieve to obtain anti-dripping flame retardant PP masterbatch.
[0044] Comparative Example 3
[0045] This comparative example is an anti-drip flame-retardant PP masterbatch. Compared with Example 1, it does not contain vinyltrimethoxysilane, but is otherwise the same. The specific preparation method is as follows:
[0046] (1) Add 10g of PP-g-GMA to 100g of NMP solvent, heat to 75℃ and stir until dissolved. Then add 20g of pentaerythritol phosphate melamine salt and 1g of SN3300 and stir until dispersed to obtain a mixture. Then add 8g of tetraethyl orthosilicate and 4g of ammonia water dropwise to the mixture and stir for 2h. The temperature of the system is controlled at 70-75℃ during the reaction. After the reaction is completed, spray dry to remove the solvent to obtain a surface-coated modified anti-dripping flame retardant.
[0047] Step (2) is the same as in Example 1.
[0048] Comparative Example 4
[0049] This comparative example is an anti-dripping flame-retardant PP masterbatch. Compared with Example 1, it does not contain an anti-dripping agent, but is otherwise the same. The specific preparation method is as follows:
[0050] (1) 10g of PP-g-GMA was added to 100g of NMP solvent and heated to 75℃ with stirring until dissolved. Then, 20g of pentaerythritol phosphate melamine salt was added and stirred until evenly dispersed to obtain a mixture. Next, 8g of tetraethyl orthosilicate, 4g of 3-aminopropyltriethoxysilane and 4g of ammonia water were added dropwise to the mixture and stirred for 2h. The system temperature was controlled at 70-75℃ during the reaction. After the reaction was completed, the solvent was removed by spray drying to obtain a surface-modified halogen-free intumescent flame retardant.
[0051] Step (2) is the same as in Example 1.
[0052] Performance testing
[0053] Sample preparation of anti-drip flame retardant PP: Take the anti-drip flame retardant masterbatches from Examples 1-2 and Comparative Examples 1-4 above and add them to PP to prepare samples;
[0054] Specifically, the anti-drip flame-retardant masterbatch was added to PP and dried together according to the proportions in Table 1 below. Then, twin-screw extrusion was performed to form a film. The temperature of the testing machine was set to 180-220℃. Flame-retardant strips with a thickness of 1.6mm were obtained by injection molding. The material was tested for tensile strength and elongation at break (refer to GB / T 1040.2-2006), flame retardancy (refer to UL94 standard for flame retardancy rating), impact strength (refer to GB / T 1043.1-2008), limiting oxygen index (refer to GB / T 2406.2-2009), dripping (refer to GB / T 2408-2021), and water resistance (the sample was weighed, immersed in 70℃ deionized water for 168h, dried until the mass was constant, weighed again, the mass change was recorded, and the LOI of the sample was tested).
[0055] Table 1 shows the percentage of raw materials used in the examples and comparative examples:
[0056]
[0057] Table 2 shows the performance of the examples and comparative examples:
[0058]
[0059] The test data above show that the anti-dripping flame-retardant PP masterbatch prepared using the method of this invention (Examples 1 and 2) can achieve the UL94 V-0 flame retardant standard at a thickness of 1.6 mm, with no melting and dripping phenomena, and the limiting oxygen index (LOI) is significantly improved to over 30%. Simultaneously, its impact strength is much higher than that of the comparative examples, proving that this invention effectively solves the problem of poor compatibility between the flame retardant and the PP matrix through a unique surface coating modification process, achieving a balance between high flame retardancy, excellent anti-dripping properties, and good mechanical properties. In contrast, any comparative examples that changed the core process steps showed varying degrees of decline in their overall performance, especially in Comparative Examples 1, 2, and 3, which demonstrates the necessity and synergy of the process steps in this invention.
[0060] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for preparing an anti-drip flame-retardant PP masterbatch, characterized in that, Includes the following steps: (1) Add 10g PP-g-GMA to 100g NMP solvent and heat to 75℃ and stir to dissolve evenly. Then add 20g pentaerythritol phosphate melamine salt and 1g SN3300 and stir to disperse evenly to obtain a mixture. Then add 8g tetraethyl orthosilicate, 4g 3-aminopropyltriethoxysilane and 4g ammonia water to the mixture and stir to react for 2h. The system temperature is controlled at 70~75℃ during the reaction. After the reaction is completed, spray dry to remove the solvent and obtain the surface-coated modified anti-dripping flame retardant. (2) Add 75g of polypropylene, 2.5g of octadecyl propionate and 2.5g of vinyl bis-stearamide to a high-speed mixer with a speed of 800rpm, stir for 3min, and then add 15g of surface-coated modified anti-dripping flame retardant and 5g of nano-montmorillonite obtained in step (1). Stir for 10min at a speed of 400rpm in the high-speed mixer to obtain a mixed material. Extrude and granulate the material through a high-torque twin-screw extruder. The discharge port adopts a tumbling mixing process. The mixed material is fed into the high-torque twin-screw extruder through a double-cone forced feeder with a feeding speed of 30Hz and a double-cone speed of 12r / min. Pass through a 170-mesh sieve to obtain anti-dripping flame retardant PP masterbatch.
2. A method for preparing an anti-drip flame-retardant PP masterbatch, characterized in that, Includes the following steps: (1) Add 10g PP-g-GMA to 100g NMP solvent and heat to 75℃ and stir to dissolve evenly. Then add 20g pentaerythritol phosphate melamine salt and 1g SN3300 and stir to disperse evenly to obtain a mixture. Then add 10g tetraethyl orthosilicate, 2g 3-aminopropyltriethoxysilane and 4g ammonia water to the mixture and stir to react for 3h. The system temperature is controlled at 70~75℃ during the reaction. After the reaction is completed, spray dry to remove the solvent and obtain the surface-coated modified anti-dripping flame retardant. (2) Add 70g of polypropylene, 2.5g of octadecyl propionate and 2.5g of vinyl bis-stearamide to a high-speed mixer with a speed of 800rpm, stir for 3min, and then add 20g of surface-coated modified anti-dripping flame retardant and 5g of nano-montmorillonite obtained in step (2). Stir for 10min at a speed of 400rpm in the high-speed mixer to obtain a mixed material. Extrude and granulate the material through a high-torque twin-screw extruder. The discharge port adopts a tumbling mixing process. The mixed material is fed into the high-torque twin-screw extruder through a double-cone forced feeder with a feeding speed of 30Hz and a double-cone speed of 12r / min. Pass through a 170-mesh sieve to obtain anti-dripping flame retardant PP masterbatch.
3. The application of the anti-drip flame-retardant PP masterbatch prepared according to claims 1-2 in PP sheets, characterized in that, The application method is as follows: anti-drip flame-retardant PP masterbatch and PP resin are mixed at a mass ratio of 10~50:100 and then melt-extruded into a mold to form anti-drip flame-retardant PP sheets.