Polypropylene-based, glass fiber reinforced, halogen-free flame retardant material compositions based on pcr

Abstract

The application discloses a glass fiber reinforced halogen-free flame-retardant material composition based on PCR polypropylene, which comprises the following raw material components in percentage by weight: a) 10-85% of PCR-PP; b) 10-50% of glass fiber; c) 5-40% of a triaryltriazine-based halogen-free flame-retardant system; d) 0-10% of an impact modifier; and e) 0-10% of a compatilizer. The material has high flame retardancy and high mechanical properties, and the additional value of the PCR-PP is improved.

Description

Technical Field

[0001] This invention relates to the field of new materials, specifically to a glass fiber reinforced halogen-free flame retardant material based on PCR polypropylene (PCR-PP). Background Technology

[0002] Polypropylene (PP), a high-performance, inexpensive, and easy-to-process general-purpose thermoplastic resin, is widely used in the automotive, home appliance, electronics, construction, and packaging industries. However, with the increasing depletion of global oil resources and the growing pollution problems caused by traditional plastic waste, the sustainable development of the plastics industry has become a global consensus. Against this backdrop, the development and utilization of post-consumer recycled polypropylene (PCR-PP) has become an important development direction for the plastics modification industry.

[0003] PCR-PP is derived from discarded household appliance casings, car bumpers, packaging containers, etc., and is produced through processes such as recycling, sorting, washing, crushing, and melt extrusion granulation. Vigorously developing PCR-PP can not only effectively alleviate the pressure of petroleum resource shortages but also significantly reduce carbon emissions.

[0004] However, compared to virgin PP, PCR-PP exhibits significant performance disadvantages. Having undergone one or more processing cycles and long-term exposure to external factors such as light, heat, and oxygen in its usage environment, PCR-PP molecular chains often experience chain breakage or cross-linking degradation, leading to unstable melt flow rate (MFR) and a substantial decrease in mechanical properties (such as impact strength and tensile strength). Furthermore, PCR-PP typically contains residual pigments, fillers, impurities, and other polymers (such as polyethylene (PE) and polystyrene (PS), which not only affects the material's appearance and color but also poses a significant challenge to its high-performance modification. Therefore, how to improve the mechanical properties and thermal stability of PCR-PP through modification techniques to reach or even exceed the performance levels of virgin materials is a critical issue that the recycled plastics industry urgently needs to address.

[0005] With the trends of lightweighting in automobiles, replacing steel with plastics, and thinning the walls of electronic and electrical products, glass fiber reinforced polypropylene (GF-PP) has become an ideal alternative to engineering plastics (such as nylon and polybutylene terephthalate PBT) and metal materials due to its excellent specific strength, heat resistance, dimensional stability, and chemical corrosion resistance. Especially in high-end applications such as battery pack housings for new energy vehicles, charging pile housings, high-power power tool housings, and 5G base station filter brackets, the material not only needs to possess high rigidity and high heat resistance, but also must meet extremely high flame-retardant safety standards.

[0006] In these applications, the flame retardancy rating typically requires compliance with UL94V-0, as defined by Underwriters Laboratories (UL). Under certain extremely demanding conditions (such as high current, high voltage, or harsh outdoor environments), materials may be required to meet UL94 5VA (for flat samples) or 5VB (for strip samples). UL94 5VA is the highest rating in vertical burning tests, requiring that after five flame impacts, no molten droplets ignite the absorbent cotton, and flat samples must not be burned through.

[0007] For a long time, brominated flame retardants (such as decabromodiphenyl ether and octabromodiphenyl ether) combined with antimony trioxide have dominated the PP flame retardant field due to their high flame retardant performance and low cost. However, brominated flame retardants release large amounts of dense smoke and toxic gases (such as dioxins and furans) during combustion or thermal decomposition, posing a serious threat to the environment and human health. With the implementation of the EU RoHS Directive, REACH Regulation, and China's "Regulations on the Restriction of Hazardous Substances in Electrical and Electronic Products," halogen-free flame retardancy has become a mandatory trend.

[0008] Currently, mainstream halogen-free flame retardant systems mainly include phosphorus-nitrogen intumescent flame retardant systems (IFR) and inorganic hydroxide flame retardant systems (such as aluminum hydroxide and magnesium hydroxide). For glass fiber reinforced PP, inorganic hydroxides usually require extremely high addition levels (often exceeding 60 wt%) to achieve the ideal flame retardant effect. This leads to a sharp increase in material density, a drastic decrease in mechanical properties (especially toughness), and processing difficulties, making it hard to meet the requirements of thin-walled parts. In contrast, intumescent flame retardant systems, due to their low smoke, non-toxicity, and non-dripping characteristics, are considered the best way to achieve halogen-free flame retardancy in glass fiber reinforced PP. However, traditional intumescent flame retardants suffer from the wicking effect in glass fiber reinforced systems, meaning that the glass fiber conducts heat and destroys the integrity of the char layer, resulting in a significant decrease in flame retardant efficiency. Achieving UL94 V-0 rating is already difficult, and achieving 5VA rating is even more challenging.

[0009] Applying PCR-PP to glass fiber reinforced applications with high flame retardancy requirements, and aiming to achieve a UL94 5VA flame retardancy rating, is an important avenue for utilizing PCR-PP and can enhance its economic value. However, it faces more complex and severe technical challenges than virgin material systems. The specific technical difficulties mainly lie in the following aspects: (1) PCR-PP has a complex origin, a wide molecular weight distribution, and contains unknown degradation products. During the high-temperature processing of flame-retardant modification, PCR-PP is prone to further thermal degradation, resulting in a decrease in melt viscosity and severe dripping. In the UL94 5VA test, preventing the dripping from igniting the absorbent cotton is one of the key indicators. The instability of the PCR matrix makes it difficult for the char layer formed by the intumescent flame retardant to adhere firmly, and it is very easy to drip off with the melt, resulting in flame retardant failure. In addition, impurities remaining in PCR (such as metal ions and other plastic particles) may catalyze the decomposition of the flame retardant, destroy the reaction mechanism of the phosphorus-nitrogen synergistic system, and result in insufficient char or loose char layer quality.

[0010] (2) In glass fiber reinforced PP, although the introduction of glass fiber improves the strength and modulus, it has a significant negative impact on flame retardant properties. This includes the following effects: a) Thermal conduction channel effect: Glass fiber is a good conductor of heat, which accelerates the transfer of heat to the interior of the material, accelerating matrix decomposition; b) Disruption of char layer continuity: During combustion, glass fiber easily punctures the expanded char layer, disrupting its thermal and oxygen-barrier integrity; c) Surface adsorption effect: The surface of glass fiber adsorbs flame retardant components from the melt, hindering their aggregation on the surface to form a dense char layer. For PCR-PP, due to the large viscosity fluctuations of the matrix itself, the dispersion and wetting of glass fiber in the matrix are more complex, further exacerbating the difficulty of char layer construction.

[0011] (3) In order to achieve the UL94 5VA rating in the PCR-PP / glass fiber system, a high proportion of intumescent flame retardant is usually required. The poor interfacial bonding between the flame retardant particles with high filler content and the PCR matrix and glass fiber leads to the material becoming extremely brittle and the notched impact strength is greatly reduced, which cannot meet the requirements of toughness in automotive parts and other scenarios.

[0012] (4) Traditional intumescent flame retardants (such as ammonium polyphosphate APP) have high water solubility and poor heat resistance. Under the high temperature and high shear environment of PCR recovery and granulation, flame retardants are prone to decomposition and failure. At the same time, in order to achieve the 5VA rating, the char layer must have extremely high strength and oxidation resistance (burn-through resistance). Impurities in PCR often act as catalysts for char layer oxidation, so that although the prepared material can pass the V-0 test, it is very easy to burn through under the severe fire of 5VA.

[0013] In conclusion, while the application of PCR-PP aligns with the global trend of green and low-carbon development, its application in high-performance, high-flame-retardant (especially UL94 5VA rating) fields remains an untapped market, fraught with technical pitfalls. Existing solutions either fail to meet stringent flame-retardant standards or sacrifice excessive mechanical properties. Therefore, developing a highly efficient halogen-free flame-retardant material composition specifically tailored to the characteristics of PCR polypropylene is particularly urgent and necessary.

[0014] In summary, the key to preparing halogen-free flame-retardant materials based on PCR-PP glass fiber reinforcement lies in a suitable halogen-free flame-retardant system. With a suitable flame-retardant system, the aforementioned technical difficulties and problems can be solved. This invention aims to provide a halogen-free flame-retardant material composition based on PCR-PP glass fiber reinforcement. By using a special halogen-free flame-retardant system, it solves the problems of dripping and char layer breakage of the PCR matrix during combustion, while reducing the amount of flame retardant added. While maintaining high mechanical strength, it achieves an ultra-high flame-retardant rating of UL94 5VA, providing a practical solution for the application of recycled plastics in high-end fields. Summary of the Invention

[0015] The main objective of this invention is to provide a halogen-free flame-retardant material based on PCR-PP that is reinforced with glass fiber and has high flame-retardant properties. By applying a special combination of halogen-free flame retardants, the flame-retardant problem and mechanical properties of PCR-PP and glass fiber are solved, thereby increasing the utilization value of PCR-PP and expanding the recycling pathways of PCR-PP.

[0016] The present invention relates to a halogen-free flame retardant material composition based on PCR-PP glass fiber reinforcement. It utilizes a synergistic system of triaryltriazine compounds and piperazine pyrophosphate as halogen-free flame retardants to solve the problems faced by existing halogen-free flame retardant systems when applied to glass fiber reinforced PCR-PP. It can achieve a high flame retardant rating of UL94 5VA and has good mechanical properties, meeting the requirements of high flame retardancy and high mechanical properties in special fields.

[0017] The present invention will now be described in detail.

[0018] This application aims to address the shortcomings of glass fiber reinforced PCR-PP materials in terms of environmental friendliness, halogen-free properties, high flame retardancy, and high performance. The inventors conducted extensive and in-depth research. To address the problems existing in the application of existing halogen-free flame retardant systems to glass fiber reinforced PCR-PP, a new, highly efficient halogen-free flame retardant system was investigated. The results showed that a synergistic flame retardant system based on a triaryltriazine compound and piperazine pyrophosphate overcomes the defects of existing flame retardant systems, achieving high flame retardancy in glass fiber reinforced PCR-PP materials, reaching UL94 5VA, while maintaining high mechanical properties. 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).

[0019] 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: .

[0020] 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 no reports have been found in the flame-retardant field.

[0021] Through research, the inventors discovered that compounding a certain amount of triphenyltriazine into piperazine pyrophosphate can significantly improve the flame retardant properties of PCR-PP, achieving the highest UL94 5 VA rating required for vertical burning. Moreover, the flame retardant has good compatibility with PCR-PP, resulting in the modified material having high mechanical properties. The prepared glass fiber reinforced PCR-PP halogen-free flame retardant material can meet the requirements of various high-standard application fields, realizing the high added value utilization of PCR-PP.

[0022] In addition, research has found that melamine derivatives can be added to the synergistic flame retardant system composed of piperazine pyrophosphate and triphenyltriazine compounds without affecting the flame retardant performance. Some melamine derivatives, such as MCA, have lower costs, which can reduce the cost of the system.

[0023] To improve the thermal stability of this system and ensure that the material does not discolor during processing, research has found that introducing a small amount of high-temperature resistant, non-precipitating zinc-containing compounds into the system can not only solve the discoloration problem but also provide flame retardancy. The zinc-containing compounds mainly refer to zinc oxide and zinc borate. These compounds, in addition to improving the thermal stability and maintaining the flame retardant properties of the system, also have a smoke-suppressing effect, reducing the smoke density of polypropylene.

[0024] In addition, for the flame retardancy of PCR-PP 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.

[0025] Through research, a high flame-retardant phosphorus-nitrogen compound halogen-free flame-retardant system for glass fiber reinforced PCR-PP was obtained, the composition of which includes: A) 50-90 wt% piperazine pyrophosphate; B) 10-50 wt% triaryltriazine; C) 0-10 wt% melamine derivatives; D) 0-10 wt% zinc-containing compounds; E) 0-2wt% anti-dripping agent.

[0026] Because PCR-PP has undergone one or more processing and use processes, and is exposed to long-term external factors such as light, heat, and oxygen in the usage environment, the molecular chains of PCR-PP often experience chain breakage or cross-linking degradation, leading to a significant decrease in its mechanical properties, especially impact resistance. Furthermore, PCR-PP usually contains residual pigments, fillers, impurities, and other polymers (such as PE and PS), which also contribute to the decline in the material's mechanical properties. To address the performance characteristics of PCR-PP and improve its mechanical properties, impact modifiers and compatibilizers need to be added.

[0027] Based on research, this invention provides a glass fiber reinforced halogen-free flame retardant material composition based on PCR polypropylene, comprising the following raw material components by weight percentage: a) 10-85% (e.g., 40%, 45%, 50%, etc.) of PCR-PP; b) 10-50% (e.g., 25%, 30%, 35%, etc.) of glass fiber; c) 5-40% (e.g., 10%, 15%, 20%, 25%, 30%, 35%, etc.) of halogen-free flame retardant systems based on triaryltriazine; d) 0-10% (e.g., 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, etc.) of impact modifier; e) 0-10% (e.g., 0.1%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, etc.) of compatibilizer.

[0028] The glass fiber reinforced halogen-free flame retardant material composition may also contain lubricants (such as silicone), antioxidants, and other additives. The amount of these additives can be designed according to conventional methods, and the present invention does not impose any particular limitation.

[0029] Furthermore, the halogen-free flame retardant system based on triaryltriazine preferably includes the following raw material components by weight percentage: A) 50-90% (e.g., 55%, 60%, 65%, 70%, etc.) of piperazine pyrophosphate (piperazine pyrophosphate). B) 10-50% (e.g., 30%, 35%, 40%, 45%, etc.) of triaryltriazine (especially triphenyltriazine). C) 0-10% (e.g., 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, etc.) of melamine derivatives; D) 0-10% (e.g., 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, etc.) zinc compounds; E) 0-2% (e.g., 0.1%, 0.5%, 1%, 1.5%, etc.) of anti-dripping agent.

[0030] 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 triaryltriazine-based halogen-free flame retardant system is 100%.

[0031] In some embodiments, the halogen-free flame retardant system based on triaryltriazine has no additional gas or carbon source.

[0032] 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).

[0033] Furthermore, the triaryltriazine preferably includes triphenyltriazine, which has the following molecular structure: .

[0034] Furthermore, the melamine derivative may include one or more of melamine cyanurate (MCA), melamine pyrophosphate, melamine polyphosphate (MPP), melamine, and melamine, with MCA generally preferred from a cost perspective. The halogen-free flame retardant system of this invention uses piperazine pyrophosphate and triaryltriazine as the main components, representing a novel halogen-free flame retardant system. A small amount of melamine derivative can be added without negatively impacting the synergistic flame retardancy of the phosphorus-nitrogen flame retardant and the triaryltriazine.

[0035] Furthermore, the zinc-containing compound may include at least one of zinc oxide and zinc borate.

[0036] Furthermore, anti-dripping agents may include modified or unmodified polytetrafluoroethylene (PTFE).

[0037] Furthermore, the impact modifier preferably includes one or more of POE (polyolefin elastomer), SEBS (styrene-ethylene-butene-styrene block copolymer), and EPDM (ethylene propylene diene monomer rubber) elastomer. These elastomers have strong impact resistance and good compatibility with PCR-PP, which will significantly improve the impact resistance of glass fiber reinforced PCR-PP halogen-free flame retardant materials.

[0038] Furthermore, the compatibilizer may include maleic anhydride-grafted polymers. More specifically, the maleic anhydride-grafted polymer preferably includes one or more of maleic anhydride-grafted PP, maleic anhydride-grafted POE, and maleic anhydride-grafted SEBS. The polarity of maleic anhydride has good compatibility with the polar components in flame retardants, and the oiliness of PP / POE / SEBS has good compatibility with PCR-PP. The compatibilizer can improve the mechanical properties of the material.

[0039] The ratio of impact modifier to compatibilizer should not be too high, as this will affect the flame retardant properties of the material.

[0040] The preparation of PCR-PP glass fiber reinforced halogen-free flame retardant materials generally involves using a twin-screw extruder with a powder inlet for adding flame retardant and a glass fiber side feed inlet. Various components are melt-blended in the extruder and then extruded and granulated.

[0041] Compared with the prior art, the beneficial effects of this invention are as follows: The glass fiber reinforced PCR-PP halogen-free flame retardant material of this application not only has high flame retardant performance, reaching the UL945VA flame retardant rating, but also has good mechanical properties, realizing the high added value utilization of PCR-PP. Detailed Implementation

[0042] 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.

[0043] raw material: (1) PCR-PP, Pujiang Jinxin; (2) Piperazine pyrophosphate, Procefu; (3) Triphenyltriazine, Shanghai Aladdin; (4) MCA, Sichuan Fine Chemicals; (5) Zinc oxide, Shanghai Aladdin; (6) Anti-dripping agent polytetrafluoroethylene, Entropy Energy New Materials; (7) Antioxidant, 1010, BASF. (8) Antioxidant, 168, BASF; (9) Silicone, Zhonglan Chenguang; (10) FP-2500S, ADEKA, a commercial brand of a compound flame retardant system based on piperazine pyrophosphate, free of triphenyltriazine, for use in polyolefins; (11) AP 766, Clariant, a commercial brand of a compound flame retardant system based on ammonium polyphosphate, free of triphenyltriazine, for use in polyolefins; (12) POE, Mitsui Chemicals; (13) Maleic anhydride grafted with POE (POE grafted with maleic anhydride), Ningbo Nengzhiguang.

[0044] (14) Fiberglass, China Giant Stone.

[0045] 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.

[0046] 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.

[0047] Extrusion granulation of materials: 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, and feed glass fiber through the side feed port. Start the main machine and feeder to complete the extrusion granulation of the material. The granulated material is sent to the silo through the pneumatic conveying system and dried.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] Example 2: 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.

[0052] Example 3: 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.

[0053] Example 4: The implementation process is the same as in Example 1, except that an anti-dripping agent 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.

[0054] Example 5: The implementation process is the same as in Example 1, except that MCA, zinc oxide, and an anti-dripping agent are added to the flame retardant system 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.

[0055] Example 6: The implementation process was the same as in Example 5, with the flame retardant system remaining unchanged, but POE increased and the PCR-PP ratio decreased. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0056] Example 7: The implementation process was the same as in Example 5, with the flame retardant system remaining unchanged, but maleic anhydride grafted onto POE was increased and the PCR-PP ratio was reduced. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0057] Example 8: The implementation process was the same as in Example 5, with the flame retardant system remaining unchanged, but POE and maleic anhydride grafted onto POE were increased, and the PCR-PP ratio was reduced. Other materials and proportions are shown in Table 1, and the resulting material results are also shown in Table 1.

[0058] 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.

[0059] 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.

[0060] Comparative Example 3: 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.

[0061] 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 was less than 10%. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0062] Comparative Example 5: The implementation process was the same as in Example 1, except that ammonium polyphosphate was 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.

[0063] Comparative Example 6: The implementation process was the same as in Example 1, except that an equal amount of FP-2500S was used to replace the synergistic system of piperazine pyrophosphate and triphenyltriazine. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0064] Comparative Example 7: The implementation process was the same as in Example 1, except that an equal amount of AP-766 was used to replace the synergistic system of piperazine pyrophosphate and triphenyltriazine. Other materials and proportions are shown in Table 2, and the resulting material results are also shown in Table 2.

[0065] Comparative Example 8: The implementation process was the same as in Example 1, except that a larger amount of FP-2500S was used to replace the synergistic system of piperazine pyrophosphate and triphenyltriazine. Other materials and proportions are shown in Table 2, and the material results are also shown in Table 2.

[0066] Table 2 The following conclusions can be drawn from the results of the examples and comparative examples: According to Example 1 and Comparative Examples 1-4, triaryltriazine compounds have synergistic effects with phosphorus-nitrogen compounds. When applied to glass fiber reinforced PCR-PP, they can achieve a UL94 5VA flame retardant rating that meets high flame retardant requirements. Compared with conventional phosphorus-nitrogen flame retardant systems, they have higher flame retardant performance and require a lower addition amount to achieve the UL94 5VA flame retardant rating, which can improve mechanical properties.

[0067] According to Examples 2-8, in the flame retardant system composed of triaryltriazine compounds and phosphorus-nitrogen compounds, the addition of small amounts of melamine derivatives, zinc oxide and anti-dripping agents still maintains synergy and still has high flame retardant efficiency.

[0068] According to Example 1 and Comparative Examples 3-4, the triaryltriazine compound and piperazine pyrophosphate need to be maintained in a certain ratio to achieve good synergy.

[0069] According to Example 1 and Comparative Example 5, the polyphosphate ammonium compound system with triaryltriazine compound is not suitable for PCR-PP material.

[0070] According to Example 1 and Comparative Examples 6-7, when applied to glass fiber reinforced PCR-PP, conventional flame retardant systems could not achieve the UL94 5VA flame retardant rating at the same addition amount.

[0071] According to Example 1 and Comparative Example 8, when applied to glass fiber reinforced PCR-PP, in order to achieve the UL94 5VA flame retardant rating, conventional flame retardant systems require a larger amount of addition, which will deteriorate the mechanical properties of the material.

[0072] According to Examples 1 and 6-8, the addition of impact modifiers and compatibilizers to the system significantly improved the mechanical properties of the material.

[0073] 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 glass fiber reinforced halogen-free flame retardant material composition based on PCR polypropylene, characterized in that, By weight percentage, it includes the following raw material components: a) 10-85% PCR-PP; b) 10-50% glass fiber; c) 5-40% of halogen-free flame retardant systems based on triaryltriazine; d) 0-10% impact modifier; e) 0-10% compatibilizer; The triaryltriazine-based halogen-free flame retardant system comprises the following raw material components by weight percentage: A) 50-90% piperazine pyrophosphate; B) 10-50% triphenyltriazine; C) 0-10% melamine derivatives; D) 0-10% zinc-containing compounds; E) 0-2% anti-dripping agent.

2. 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.

3. 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.

4. 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.

5. The high flame-retardant halogen-free flame-retardant system for polypropylene according to claim 1, characterized in that, Impact modifiers include one or more of POE, SEBS elastomers, and EPDM elastomers.

6. The high flame-retardant halogen-free flame-retardant system for polypropylene according to claim 1, characterized in that, Compatibilizers include maleic anhydride-grafted polymers.

7. The high flame-retardant halogen-free flame-retardant system for polypropylene according to claim 1, characterized in that, Maleic anhydride-grafted polymers include one or more of maleic anhydride-grafted PP, maleic anhydride-grafted POE, and maleic anhydride-grafted SEBS.

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