Highly flame-retardant halogen-free flame-retardant system for polypropylene and application thereof

Abstract

The application discloses a high-flame-retardant halogen-free flame-retardant system for polypropylene and application thereof. The halogen-free flame-retardant system is based on phosphorus-nitrogen compounds and aryl triazine compounds, and raw material compositions include: a) 50-90 wt% of phosphorus-nitrogen flame retardant; b) 10-50 wt% of triaryl triazine; c) 0-10 wt% of melamine derivative; d) 0-10 wt% of zinc-containing compound; and e) 0-2 wt% of anti-dripping agent. The halogen-free flame-retardant polypropylene prepared by using the flame-retardant system can reach the UL94 5VA flame-retardant standard.

Description

Technical Field

[0001] This invention relates to the field of new materials, specifically to a highly flame-retardant phosphorus-nitrogen halogen-free flame-retardant hybrid system of triaryltriazine synergy applicable to polypropylene and its application. Background Technology

[0002] Polypropylene (PP), a semi-crystalline thermoplastic polymer, is valued for its excellent physical and mechanical properties, good chemical stability, resistance to acid and alkali corrosion, and ease of processing. PP material has a low density (approximately 0.90-0.92 g / cm³). 3 Polypropylene (PP) is the lowest density of common plastics and possesses excellent heat resistance and electrical insulation properties, making it widely used in electronics, automotive parts, appliance housings, and construction. Particularly in the electronics industry, as equipment evolves towards miniaturization, integration, and high performance, higher requirements are being placed on the heat resistance and mechanical strength of polypropylene as a structural and housing material.

[0003] However, polypropylene (PP) has a significant drawback: its flammability. PP is a hydrocarbon polymer with a limiting oxygen index (LOI) of only 17%-18%, making it highly flammable upon contact with a flame source. The combustion is rapid and accompanied by molten droplets. These droplets often carry a large amount of heat, which can not only ignite surrounding combustibles and cause the fire to spread, but also potentially cause secondary damage to the precision components inside electronic devices. Therefore, to meet the stringent safety standards for electronic and electrical products, polypropylene must be modified to be flame-retardant.

[0004] Currently, flame retardant systems used in polypropylene are mainly divided into two categories: halogenated flame retardants and halogen-free flame retardants. Halogenated flame retardants (such as decabromodiphenyl ether and hexabromocyclododecane) dominated the market for a long time due to their high flame retardant efficiency, low dosage, minimal impact on the mechanical properties of the substrate, and relatively low price. Halogenated flame retardants primarily work through a gas-phase flame retardant mechanism, releasing hydrogen halide free radicals during combustion to capture active free radicals in the combustion chain reaction, thereby inhibiting flame propagation. However, halogenated flame retardants produce large amounts of dense smoke, corrosive gases (such as hydrogen halides), and carcinogenic substances like dioxins during combustion or thermal decomposition. This not only causes persistent environmental pollution but also severely hinders escape and rescue efforts during fires. With increasingly stringent global environmental regulations, the use of halogenated flame retardants has been strictly limited, making the development of environmentally friendly halogen-free flame-retardant polypropylene an inevitable trend in the industry.

[0005] Existing halogen-free flame retardant systems mainly include inorganic hydroxides (such as aluminum hydroxide and magnesium hydroxide), phosphorus-nitrogen intumescent flame retardants (IFR), and phosphorus-nitrogen-inorganic synergistic flame retardant systems. While inorganic hydroxides are environmentally friendly and suppress smoke, achieving ideal flame retardant performance (such as UL94 V-0 rating) often requires a filler content as high as 50%-60%. Such a high filler content leads to deterioration of the processing performance of the polypropylene matrix, a sharp decrease in impact strength and tensile strength, making the material brittle and unable to meet the toughness and strength requirements of electronic and electrical appliance casings. In contrast, intumescent flame retardants (IFR) have become a research hotspot in recent years. IFR systems typically consist of an acid source, a gas source, and a char source. During combustion, IFR expands on the polymer surface to form a porous, dense char layer, providing insulation, oxygen barrier, and inhibiting the escape of combustible gases. IFR systems can achieve UL94 V-0 rating for polypropylene at relatively low addition levels. Currently, in IFRs using polypropylene, the acid source is the main component, usually a phosphorus-containing compound. It primarily generates acidic substances during high-temperature processes, which promote polymer decomposition and the dehydration and carbonization of the char-forming agent. Industrially, crystalline type II ammonium polyphosphate (APP) and piperazine pyrophosphate are commonly used. The gas source compound mainly decomposes upon heating, releasing large amounts of non-flammable gases, reducing oxygen concentration, and becoming a foaming agent for forming the expansion layer. The expansion layer provides thermal and oxygen insulation and is usually a nitrogen-containing compound, with melamine derivatives such as melamine cyanurate (MCA) being commonly used. The carbon source is the material basis for forming the final physical carbon layer. It undergoes dehydration and carbonization under the catalysis of the acid source, providing the carbon elements needed to form a robust carbon layer. The resulting expanded carbon layer has thermal and oxygen-insulating properties, effectively preventing the transfer of heat and oxygen to the substrate and preventing the diffusion of flammable gases generated by the thermal decomposition of the substrate. Common carbon sources are polyhydroxy compounds, such as pentaerythritol.

[0006] The existing IFR systems mainly include two types: (1) those based on piperazine pyrophosphate and melamine pyrophosphate, which have good flame retardant properties and low water solubility, and do not cause moisture absorption or migration in polymers, and can be applied to polyolefins, such as commercial brands like FP-2500; (2) those based on crystalline type II APP, where APP is used as an acid source, combined with MCA and pentaerythritol as gas and carbon sources, respectively. Both systems, with certain addition amounts, can achieve the UL94 V0 flame retardant requirement.

[0007] With the continuous expansion of application scenarios, especially in high-end electronic appliances, 5G communication base station power modules, electric vehicle battery pack brackets, and rail transit interiors, more stringent requirements are being placed on the flame-retardant performance of materials. These scenarios not only require materials to pass the conventional vertical burning test (UL94 V-0), but often also the UL94 5V level test (including 5VA and 5VB). The UL94 5V level test simulates a more intense fire scenario, using a flame with a power of up to 1250W (approximately 2.5 times that of 500W) to directly impact the sample, and includes multiple ignition cycles. This poses a significant challenge to the stability, strength, and thermal insulation performance of the char layer in the flame-retardant system.

[0008] Unfortunately, existing conventional halogen-free flame retardant systems are inadequate for the UL94 5V rating test. Ordinary intumescent flame-retardant polypropylene often forms an overly porous and fragile char layer under 5V flame impact, unable to withstand the erosion of high-pressure flames and high-temperature heat flow, leading to rapid burn-through of the sample. To achieve a 5VA rating, it is usually necessary to significantly increase the amount of flame retardant added, which directly results in a precipitous drop in the mechanical properties of the composite material, especially extremely low notched impact strength, making it impossible to meet the assembly and usage requirements of structural components. Furthermore, high filler content also brings problems such as high melt viscosity, difficulty in injection molding, surface fiber floating, and severe precipitation.

[0009] In summary, although some progress has been made in halogen-free flame-retardant polypropylene, existing flame-retardant systems face an irreconcilable contradiction between achieving extremely high flame-retardant ratings (such as UL94 5VA) and maintaining excellent mechanical properties. Traditional intumescent flame retardants suffer from insufficient char strength and poor erosion resistance, while highly filled inorganic flame retardants severely sacrifice the material's mechanical properties. Therefore, developing a novel halogen-free flame-retardant system with high flame-retardant efficiency, low addition amount, and significantly improved char strength and stability is of significant practical importance and urgent market demand for promoting the application of polypropylene in high-end electronics and electrical appliances and special safety fields.

[0010] This invention addresses the shortcomings of existing phosphorus-nitrogen compound flame retardant systems applied to polypropylene materials by developing a novel halogen-free flame retardant system with high flame retardant performance for polypropylene materials. Based on this system, halogen-free flame retardant polypropylene materials can be prepared that meet UL94 5VA flame retardant requirements. Summary of the Invention

[0011] The main objective of this invention is to provide a novel halogen-free flame-retardant compound system with high flame-retardant properties for use in polypropylene, overcoming the defects of existing flame-retardant systems. This newly invented flame-retardant system has high flame-retardant characteristics and can be applied to polypropylene materials to obtain halogen-free flame-retardant polypropylene materials that achieve the UL94 5VA flame-retardant rating. It can be used to manufacture components or products in the fields of electronics, electrical appliances, and automobiles.

[0012] This invention relates to the development of a novel halogen-free flame-retardant compound system for polypropylene to achieve a UL94 5VA flame retardant rating. It utilizes triaryltriazine compounds as flame-retardant synergists, and through synergy with phosphorus and nitrogen flame retardants, forms a compound flame-retardant system with high flame-retardant performance, overcoming the shortcomings of existing flame-retardant systems that cannot meet the UL94 5VA flame-retardant requirement. This novel flame-retardant system is well-suited for polypropylene materials, resulting in high-performance halogen-free flame-retardant materials. The composition of this halogen-free flame-retardant compound system includes: a) 50-90 wt% phosphorus-nitrogen flame retardant; b) 10-50 wt% of triaryltriazine; c) 0-10 wt% of melamine derivatives; d) 0-10 wt% zinc-containing compounds; e) 0-2wt% anti-dripping agent.

[0013] This halogen-free flame-retardant compound system, when applied to polypropylene, can meet the UL94 5VA flame-retardant standard.

[0014] The present invention will now be described in detail.

[0015] This application aims to address the insufficient flame retardant performance of existing halogen-free flame retardant systems used in polypropylene materials. The inventors conducted extensive and in-depth research. Addressing the problems of existing phosphorus-nitrogen-based flame retardant systems in flame-retardant polypropylene, a new flame retardant system was investigated. The results showed that adding a triaryltriazine compound to a phosphorus-nitrogen-containing compound significantly improved flame retardant performance, achieving a UL94 5VA flame retardant rating, without requiring the addition of conventional gas and char source compounds. The chemical structure of the triaryltriazine compound is shown below: R1, R2, and R3 are aromatic groups, which can be chosen independently, and can be completely the same or not completely the same (including completely different groups, two of which are the same and the remaining one is different).

[0016] From a molecular structure perspective, triaryltriazines possess a triazine and polybenzene ring structure, with nitrogen content in the triazine structure. The most typical compound of triaryltriazines is triphenyltriazine, whose molecular structure is shown below: .

[0017] Triphenyltriazine is a white or pale yellow powder with a melting point greater than 230°C and a boiling point of approximately 541°C. It is insoluble in water, exhibits good thermal stability, and possesses the physical properties suitable for use in polypropylene. Its applications have been reported in organic light-emitting diode (OLED) optoelectronic materials, pharmaceutical intermediates, and metal corrosion protection, but its use as a flame retardant synergist has not been reported.

[0018] Through research, the inventors discovered that a flame-retardant system formed by compounding a certain amount of triphenyltriazine into a phosphorus-nitrogen-containing acid source compound has excellent flame-retardant properties and stable flame-retardant performance, meeting the UL94 5VA flame-retardant requirements. For other applications with lower flame-retardant requirements, the amount of flame retardant added can be reduced, and the mechanical properties can be improved.

[0019] From the molecular structure of triphenyltriazine, the triazine structure releases non-flammable gas at high temperatures, while the polybenzene ring structure has a high carbon content and easily forms a carbon layer at high temperatures. According to the halogen-free flame retardant theory, the flame retardant combination in this application may act as both a gas source and a carbon source, and synergistically improves the flame retardant performance of the system with phosphorus and nitrogen-containing acid source compounds. The formation of a complex flame retardant system between phosphorus and nitrogen-containing acid source compounds and triaryltriazine (especially triphenyltriazine) is a first discovery in this application.

[0020] Research has found that phosphorus-nitrogen-containing acid source compounds that can synergize well with triphenyltriazine compounds include crystalline type II ammonium polyphosphate (APP) and piperazine pyrophosphate, but do not have good synergistic flame retardant effects with other non-phosphorus-nitrogen-containing compounds.

[0021] In addition, research has found that melamine derivatives can be added to the synergistic flame retardant system composed of phosphorus and nitrogen-containing acid source compounds and triphenyltriazine compounds in this application without affecting the flame retardant performance. Some melamine derivatives, such as MCA, have lower costs, which can reduce the cost of the system.

[0022] To improve the thermal stability of the system and ensure that the material does not discolor during processing, the inventors discovered that introducing a small amount of high-temperature resistant, non-precipitating zinc-containing compounds into the system not only solves the discoloration problem but also provides flame retardancy. These zinc-containing compounds mainly refer to zinc oxide and zinc borate. Besides improving the system's thermal stability and maintaining its flame retardant properties, these compounds also have a smoke-suppressing effect, reducing the smoke density of polypropylene.

[0023] In addition, for the flame retardancy of polypropylene, there is a certain amount of dripping. A small amount of anti-dripping agent can be added to the system. The anti-dripping agent is polytetrafluoroethylene (PTFE) or modified polytetrafluoroethylene. The addition of anti-dripping agent can improve the flame retardant performance and reduce the amount of flame retardant used.

[0024] Through research, the first aspect of this invention provides a high flame-retardant halogen-free flame-retardant system (halogen-free flame-retardant compound composition) for polypropylene, the raw material composition of which includes: a) 50-90 wt% (e.g., 55 wt%, 60 wt%, 65 wt%, 70 wt%, etc.) of phosphorus-nitrogen flame retardants; b) 10-50 wt% (e.g., 30 wt%, 35 wt%, 40 wt%, 45 wt%, etc.) of triaryltriazine (especially triphenyltriazine); c) 0-10 wt% (e.g., 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, etc.) of melamine derivatives; d) 0-10 wt% (e.g., 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, etc.) of zinc-containing compounds; e) 0-2wt% (e.g., 0.1wt%, 0.5wt%, 1wt%, 1.5wt%, etc.) of anti-dripping agent.

[0025] In some embodiments, the total mass percentage of phosphorus-nitrogen flame retardant, triaryltriazine (especially triphenyltriazine), melamine derivative, zinc-containing compound and anti-dripping agent in the high flame retardant halogen-free flame retardant system for polypropylene is 100%.

[0026] In some embodiments, the polypropylene high flame retardant halogen-free flame retardant system has no additional gas or carbon source.

[0027] Furthermore, the phosphorus-nitrogen flame retardant preferably includes at least one of ammonium polyphosphate and piperazine pyrophosphate (piperazine pyrophosphate).

[0028] Furthermore, triaryltriazine has the following molecular structure: R1, R2, and R3 are aromatic groups, which can be chosen independently, and can be completely the same or not completely the same (including completely different groups, two of which are the same and the remaining one is different).

[0029] Furthermore, the triaryltriazine preferably includes triphenyltriazine, which has the following molecular structure: .

[0030] Furthermore, the melamine derivatives may include one or more of melamine cyanurate (MCA), melamine pyrophosphate, melamine polyphosphate (MPP), melamine, and melamine. The halogen-free flame retardant system of this invention uses phosphorus-nitrogen flame retardants and triaryltriazine (especially triphenyltriazine) as the main components, representing a novel halogen-free flame retardant system. A small amount of melamine derivatives can be added without negatively affecting the synergistic flame retardancy of the phosphorus-nitrogen flame retardants and triaryltriazine (especially triphenyltriazine).

[0031] Furthermore, the zinc-containing compound may include at least one of zinc oxide and zinc borate.

[0032] Furthermore, anti-dripping agents may include modified or unmodified polytetrafluoroethylene (PTFE).

[0033] Furthermore, the average particle size D50 of the high flame-retardant halogen-free flame-retardant system for polypropylene is 1 μm. <D50<40μm。

[0034] The second aspect of this invention provides the application of the high flame-retardant halogen-free flame-retardant system for polypropylene described in the first aspect in polypropylene composite materials. The amount of the high flame-retardant halogen-free flame-retardant system for polypropylene added to the polypropylene composite material can be 1-50 wt% (e.g., 20 wt%, 25 wt%, etc.), which can meet different flame-retardant ratings.

[0035] Furthermore, the polypropylene in the polypropylene composite material may include at least one of homopolymer polypropylene and copolymer polypropylene.

[0036] Furthermore, the polypropylene composite material may also include at least one of glass fiber and filler.

[0037] To prepare halogen-free flame-retardant polypropylene, the flame-retardant system needs to be uniformly dispersed in the material. This can be achieved by using a twin-screw extruder with a feed inlet for flame-retardant powder, where the various components are melt-blended and then extruded and granulated.

[0038] Compared with the prior art, the beneficial effects of this invention are as follows: The flame retardant system of phosphorus-nitrogen compounds and triaryltriazine (especially triphenyltriazine) provided by this invention overcomes the defects of existing flame retardant systems. It can be used as a halogen-free flame retardant system for polypropylene and can be used to prepare novel halogen-free flame retardant polypropylene materials for electrical and electronic and automotive applications, achieving a UL94 5VA flame retardant rating. Detailed Implementation

[0039] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Operating methods not specifically specified in the following embodiments are generally performed under conventional conditions or as recommended by the manufacturer.

[0040] raw material: (1) Piperazine pyrophosphate: Qingyuan Procefu; (2) Triphenyltriazine, Shanghai Aladdin; (3) MCA, Sichuan Fine Chemicals Research Institute; (4) Zinc oxide, Shanghai Aladdin; (5) Anti-dripping agent polytetrafluoroethylene, Entropy Energy New Materials; (6) Polypropylene, S1003, Shanghai SECCO; (7) Antioxidant, 1010, BASF. (8) Antioxidant, 168, BASF; (9) Silicone, Zhonglan Chenguang; (10) Type II ammonium polyphosphate (APP), Hangzhou Jiersi; (11) Melamine polyphosphate (MPP), Sichuan Fine Chemicals Research Institute; (12) Pentaerythritol, Sinopharm Group.

[0041] Example 1: When a compound flame retardant system is applied to polypropylene, the performance of the flame retardant is examined according to the following steps and test methods.

[0042] Mixing of halogen-free flame retardant system: Add the pre-weighed components of the compound flame retardant system and other additives according to the formula to a high-speed mixer, start high-speed mixing, mix for 10 minutes to complete the mixing of halogen-free flame retardant system, and discharge the material.

[0043] Extrusion granulation of the material: Set the temperature of each zone of the twin-screw extruder to the predetermined temperature. After the temperature stabilizes for 20 minutes, add polypropylene from the hopper. Add flame retardant powder through the powder feed port. Start the main machine and feeder to complete the extrusion granulation of the material. The granulated material is then sent to the silo via a pneumatic conveying system and dried.

[0044] Material Application and Testing: The dried material is injection molded into standard specimens according to various testing standards using an injection molding machine, and relevant material properties are tested. The following performance indicators are the main focus: Flame retardancy: Tested according to the UL94 5VA standard (according to the standard, it must first pass the UL94 V0 test, and then the UL94 5VA test). PASS indicates that the flame retardancy has been passed, and FAIL indicates that it has not passed.

[0045] Material mechanical properties: Impact strength is tested according to ASTM D256. The addition of flame retardants usually reduces the impact performance of the material. The greater the amount added, the lower the impact performance.

[0046] The materials and proportions in the examples are shown in Table 1 (unit: parts by mass), and the material test results are shown in Table 1.

[0047] Example 2: The implementation process was the same as in Example 1, except that the relative ratio of piperazine pyrophosphate and triphenyltriazine was changed while keeping the total amount of the flame retardant system constant. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0048] Example 3: The implementation process is the same as in Example 1, except that piperazine pyrophosphate is replaced with ammonium polyphosphate, while keeping the total amount of the flame retardant system unchanged. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0049] Example 4: The implementation process is the same as in Example 1, except that MCA is added to the flame retardant system while keeping the total amount of the flame retardant system constant. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0050] Example 5: The implementation process is the same as in Example 1, except that zinc oxide is added to the flame retardant system while keeping the total amount of the flame retardant system constant. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0051] Example 6: The implementation process is the same as in Example 4, except that zinc oxide is added to the flame retardant system while keeping the total amount of the flame retardant system constant. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0052] Example 7: The implementation process is the same as in Example 1, except that an anti-dripping agent is added to the flame retardant system. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0053] Example 8: The implementation process is the same as in Example 6, except that an anti-dripping agent is added to the flame retardant system. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0054] Table 1 Comparative Example 1: The implementation process is the same as in Example 1, except that only piperazine pyrophosphate is used. Other materials and proportions are shown in Table 2 (unit: parts by mass), and the material results are shown in Table 2.

[0055] Comparative Example 2: The implementation process was the same as in Example 1, except that only triphenyltriazine was used. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0056] Comparative Example 3: The implementation process is the same as in Example 1, except that only ammonium polyphosphate is used. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0057] Comparative Example 4: The implementation process was the same as in Example 1, except that the ratio of piperazine pyrophosphate to triphenyltriazine was adjusted so that the triphenyltriazine ratio exceeded 50%. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0058] Comparative Example 5: The implementation process was the same as in Example 1, except that the ratio of piperazine pyrophosphate to triphenyltriazine was adjusted so that the triphenyltriazine ratio was less than 10%. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0059] Comparative Example 6: The implementation process is the same as in Example 1, except that MCA is used instead of piperazine pyrophosphate. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0060] Comparative Example 7: The implementation process was the same as in Example 1, except that an equal amount of a conventional phosphorus-nitrogen flame retardant system composed of piperazine pyrophosphate and MPP was used. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0061] Comparative Example 8: The implementation process was the same as in Example 1, except that a conventional phosphorus-nitrogen flame retardant system composed of APP, MCA, and pentaerythritol was used. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0062] Comparative Example 9: The implementation process was the same as in Comparative Example 7, except that the total amount of the compound system consisting of piperazine pyrophosphate and MPP was increased, and zinc oxide and an anti-dripping agent were also added. Other materials and proportions are shown in Table 2, and the material results are also shown in Table 2.

[0063] Table 2 The following conclusions can be drawn from the results of the examples and comparative examples: Based on the results of Examples 1-3 and Comparative Examples 1-3 and 7-9, the triphenyltriazine compound has a synergistic effect with the phosphorus-nitrogen compound, which can achieve the UL94 5VA flame retardant rating with higher flame retardant requirements. Compared with conventional phosphorus-nitrogen flame retardant systems, it has higher flame retardant performance and requires a lower addition amount to achieve the UL94 5VA flame retardant rating, which can improve mechanical properties.

[0064] According to Example 4, in the flame retardant system composed of triphenyltriazine compound and phosphorus-nitrogen compound, the addition of a small amount of melamine derivative still maintains synergy and still has high flame retardant efficiency.

[0065] According to Example 5, adding a small amount of zinc-containing compound to the system of this application can improve mechanical properties without reducing flame retardant properties.

[0066] According to Example 7, adding a small amount of anti-dripping agent to the system of this application can improve the performance of the flame retardant, reduce the amount of flame retardant used, and improve the mechanical properties.

[0067] According to Example 1 and Comparative Examples 4-5, the triphenyltriazine compound and the phosphorus-nitrogen-containing compound need to be maintained in a certain ratio to achieve good synergy.

[0068] According to Example 1 and Comparative Example 6, the triphenyltriazine compound exhibits poor synergy with other phosphorus- and nitrogen-free compounds.

[0069] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A high flame-retardant halogen-free flame-retardant system for polypropylene, characterized in that, The raw material composition includes: a) 50-90 wt% phosphorus-nitrogen flame retardant; b) 10-50 wt% triphenyltriazine; c) 0-10 wt% of melamine derivatives; d) 0-10 wt% zinc-containing compounds; e) 0-2wt% anti-dripping agent.

2. The high flame-retardant halogen-free flame-retardant system for polypropylene according to claim 1, characterized in that, Phosphorus-nitrogen flame retardants include at least one of ammonium polyphosphate and piperazine pyrophosphate.

3. The high flame-retardant halogen-free flame-retardant system for polypropylene according to claim 1, characterized in that, Melamine derivatives include one or more of melamine cyanurate, melamine pyrophosphate, melamine polyphosphate, melamine, and melamine.

4. The high flame-retardant halogen-free flame-retardant system for polypropylene according to claim 1, characterized in that, Zinc-containing compounds include at least one of zinc oxide and zinc borate.

5. The high flame-retardant halogen-free flame-retardant system for polypropylene according to claim 1, characterized in that, Anti-dripping agents include modified or unmodified polytetrafluoroethylene.

6. The high flame-retardant halogen-free flame-retardant system for polypropylene according to claim 1, characterized in that, The average particle size D50 of the high flame-retardant halogen-free flame-retardant system for polypropylene is 1 μm. <D50<40μm。 7. The application of the high flame-retardant halogen-free flame-retardant system for polypropylene according to any one of claims 1 to 6 in polypropylene composite materials, characterized in that, The amount of polypropylene high flame retardant halogen-free flame retardant system added to the polypropylene composite material is 20-50 wt%.

8. The application according to claim 7, characterized in that, The polypropylene composite material contains at least one of homopolymer polypropylene and copolymer polypropylene. The polypropylene composite material also includes at least one of glass fiber and filler.

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