Halogen-free flame-retardant compound system synergized by alkyl phosphate metal salt for vinyl polymers and application thereof
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 新疆天利高新石化股份有限公司
- Filing Date
- 2026-04-22
- Publication Date
- 2026-08-07
AI Technical Summary
[0003]对于乙烯基聚合物的阻燃，面临两个问题：一是分子结构中含有大量碳氢键，自身不能成碳，因此氧指数较低；其次，与聚丙烯不同，乙烯基聚合物在高温时，由于熔体强度较大，对于膨胀型阻燃剂难以发泡，膨胀阻燃剂对乙烯基聚合物的阻燃效率较差
本发明所提供的烷基磷酸酯金属盐增效的基于哌嗪焦磷酸盐复配阻燃体系，克服了现有阻燃体系的缺陷，可以用作乙烯基聚合物的无卤阻燃体系，可以制备新型的应用于电线电缆、电气电子、汽车领域的无卤阻燃乙烯基聚合物专用材料。
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Abstract
Description
Technical Field
[0001] This invention relates to a halogen-free flame-retardant compound system for vinyl polymers enhanced with alkyl phosphate metal salts, and more particularly to a halogen-free flame-retardant compound system for use with vinyl polymers. The aim is to obtain a highly flame-retardant, migration-free flame-retardant system, belonging to the field of new materials. Background Technology
[0002] Vinyl polymers, primarily referring to polyethylene, EVA, and other polymeric materials prepared using ethylene as a monomer, are widely used in wire and cable, electronics, automobiles, and new energy fields due to their good mechanical properties, low-temperature resistance, and relatively low cost. These applications necessitate flame-retardant properties, but vinyl polymers are flammable; therefore, the flame-retardant issue needs to be addressed when using them in these applications.
[0003] Two challenges exist in flame retardancy for vinyl polymers: first, their molecular structure contains numerous carbon-hydrogen bonds, preventing them from forming carbon themselves, resulting in a low oxygen index; second, unlike polypropylene, vinyl polymers exhibit high melt strength at high temperatures, making it difficult for intumescent flame retardants to foam, thus reducing their flame-retardant efficiency. Therefore, flame retardancy of vinyl polymers is more challenging than that of other polymers. Currently, flame retardants used in vinyl polymer materials fall into two basic categories: halogenated and non-halogenated systems. Halogenated systems typically involve brominated flame retardants combined with antimony trioxide. Numerous studies have shown that vinyl polymer materials containing brominated flame retardants produce dense smoke and harmful substances such as hydrogen bromide during combustion, which can cause asphyxiation. Therefore, developing safe, environmentally friendly, and halogen-free flame retardant systems for vinyl polymers has become a research hotspot, leading to the emergence of novel halogen-free flame retardants or flame retardant systems for vinyl polymers in recent years.
[0004] Halogen-free flame retardants used in vinyl polymers mainly fall into two basic categories: inorganic hydroxide systems, including magnesium hydroxide and aluminum hydroxide; and phosphorus-nitrogen systems, which include two subsystems: ammonium polyphosphate (APP) based on high polymerization degree and piperazine pyrophosphate based. Phosphorus-nitrogen systems are intumescent flame retardant systems. For inorganic hydroxide systems, their flame retardant effect is limited. To meet various specifications and standards, the addition amount is usually very high, sometimes exceeding 65% of the entire formulation. Since inorganic hydroxide flame retardants are incompatible with vinyl polymers and are dispersed in the matrix resin as a filler, high filling amounts significantly reduce the material's mechanical properties. Sometimes, red phosphorus is used in conjunction with inorganic hydroxide to reduce the amount added, but the application of red phosphorus causes color issues in the material, and the combustion of red phosphorus easily produces toxic gases such as phosphine and large amounts of smoke; therefore, this is not the optimal solution. For high-polymerization-degree ammonium polyphosphate (APP) flame retardant systems, it is an intumescent flame retardant system. Due to its strong flame retardancy, its addition amount is much lower than that of inorganic hydroxide systems. However, due to its hydrophilic surface properties, APP has poor compatibility with vinyl polymers. Therefore, the mechanical strength of vinyl polymer materials retarded by APP system is still very low. More critically, due to the high water solubility of APP, it is easy to absorb moisture. After a period of time, water droplets will be present on the surface of vinyl polymer products, which will greatly reduce the insulation performance of the material and bring safety hazards. Secondly, the poor compatibility between APP system and vinyl polymers, with obvious migration from the inside of the material to the surface, will reduce the content of internal flame retardant over time, and the flame retardant performance of the material will decrease or even disappear. However, the flame retardant effect of piperazine pyrophosphate system is still insufficient and needs to be combined with melamine pyrophosphate. This system overcomes the defects of APP in terms of moisture absorption and migration, but faces several problems: large addition amount, poor mechanical properties of material; unstable flame retardant performance, easy dripping, usually requires the addition of PTFE-based anti-dripping agent, which is usually polytetrafluoroethylene, and the use of perfluorinated compounds is increasingly restricted; and poor thermal stability, easy to yellow.
[0005] In summary, the main drawbacks of current flame-retardant systems applied to vinyl polymers are: unstable flame-retardant performance, high additive dosage, poor material mechanical properties, and the need to add restricted components. Therefore, there is a need to develop novel halogen-free flame-retardant systems for vinyl polymers.
[0006] This invention addresses the shortcomings of existing piperazine pyrophosphate-based phosphorus-nitrogen compound flame retardant systems applied to vinyl polymer materials by developing a novel halogen-free flame retardant system for vinyl polymer materials, and based on this system, halogen-free flame retardant vinyl polymer materials can be prepared. Summary of the Invention
[0007] The main object of the present invention is to provide a novel halogen-free flame retardant compounding system for vinyl polymers, overcoming the defects of existing flame retardant systems. The newly invented flame retardant system has characteristics such as high flame retardancy and no migration. It can be applied to vinyl polymer materials to obtain halogen-free flame retardant vinyl polymer materials, and can be used to prepare components or products in the fields of wire and cable, electronic appliances, automobiles, etc.
[0008] To achieve the above object, the basic solution provided by the present invention is: a halogen-free flame retardant compounding system synergized with alkyl phosphate metal salts for vinyl polymers. By weight percentage, its composition includes: 40-99 wt% of piperazine pyrophosphate; 1-60 wt% of alkyl phosphate metal salts; 0-60 wt% of melamine derivatives; 0-10% of zinc-containing compounds; 0-1% of PTFE-based anti-dripping agents; 0-20% of charring agents; the melamine derivatives include at least one of melamine pyrophosphate, melamine polyphosphate, melamine cyanurate, and melamine condensates, and the charring agent is an organic compound containing hydroxyl groups or an oxygen-containing polymer with a benzene ring.
[0009] Further, the average particle size of the alkyl phosphate metal salt is 1 < D50 < 40 μm, and it has the following structural formula: Where R1 and R2 are straight-chain aliphatic saturated hydrocarbon groups and unsaturated hydrocarbon groups, and can also be aromatic groups, which can be the same or different; M is a metal element.
[0010] Further, the alkyl phosphate metal salt is methyl methyl phosphate aluminum. The alkyl phosphate metal salt can synergize the flame retardant performance of the flame retardant system based on piperazine pyrophosphate, forming a new flame retardant system with good flame retardant characteristics, stable flame retardant performance, and can reduce the addition amount. [[ID=1##]]
[0011] Further, the average particle size of the piperazine pyrophosphate is 1 < D50 < 40 μm.
[0012] Further, the average particle size of the melamine derivative is 1 < D50 < 40 μm.
[0013] Further, the zinc-containing compounds include zinc oxide, zinc borate or zinc stannate. The zinc-containing compounds have a very high decomposition temperature, low water solubility, and do not migrate and precipitate. They can cooperate with the phosphorus-nitrogen system to improve the thermal stability of the system, and have a smoke suppression effect, reducing the smoke density of vinyl polymers. <000##]]
[0014] Further, the PTFE-based anti-dripping agent is modified core-shell polytetrafluoroethylene. The PTFE-based anti-dripping agent can further improve the flame retardancy. However, the new system can still have high flame retardancy without adding the PTFE-based anti-dripping agent, avoiding the use of restricted fluorine-containing components.
[0015] Application of a halogen-free flame retardant compounding system synergized with an alkyl phosphate metal salt for vinyl polymers, wherein the flame retardant compounding system is applied to vinyl polymers, and its addition amount is 10-60 wt%.
[0016] Further, the vinyl polymer includes polyethylene, EVA or their blends.
[0017] Compared with the prior art, the advantages of the present invention are as follows: The piperazine pyrophosphate-based compound flame retardant system synergized with an alkyl phosphate metal salt provided by the present invention overcomes the defects of the existing flame retardant systems and can be used as a halogen-free flame retardant system for vinyl polymers, and can prepare novel halogen-free flame retardant vinyl polymer special materials applied to the fields of wire and cable, electrical and electronics, and automobiles. Detailed Description of the Invention
[0018] The present invention will be further described in detail below through specific embodiments: A halogen-free flame retardant compounding system synergized with an alkyl phosphate metal salt for vinyl polymers, by weight percentage, its composition includes: 40-99 wt% of piperazine pyrophosphate; 1-60 wt% of alkyl phosphate metal salt; 0-60 wt% of melamine derivatives; 0-10% of zinc-containing compounds; 0-1% of PTFE-based anti-dripping agent; 0-20% of charring agent, wherein: The alkyl phosphate metal salt is preferably methyl methyl phosphate aluminum, and the average particle size of the alkyl phosphate metal salt is 1 < D50 < 40 um, and it has the following structural formula: Where R1 and R2 are straight-chain aliphatic saturated hydrocarbon groups and unsaturated hydrocarbon groups, and can also be aromatic groups, which can be the same or different; M is a metal element.
[0019] The average particle size of piperazine pyrophosphate is 1 < D50 < 40 um. The melamine derivatives include at least one of melamine pyrophosphate, melamine polyphosphate, melamine cyanurate, and melamine condensates, and the average particle size of the melamine derivatives is 1 < D50 < 40 um. The zinc-containing compounds include zinc oxide, zinc borate or zinc stannate. The PTFE-based anti-dripping agent is modified core-shell polytetrafluoroethylene. The charring agent is an organic compound containing hydroxyl groups or an oxygen-containing polymer with a benzene ring.
[0020] Application of a halogen-free flame-retardant compound system for vinyl polymers enhanced with alkyl phosphate metal salts, wherein the flame-retardant compound system is applied to vinyl polymers at an addition amount of 10-60 wt%. Vinyl polymers include polyethylene, EVA, or blends thereof.
[0021] Raw material source description: (1) Piperazine pyrophosphate: Yuntianhua (2) Melamine pyrophosphate: Yuntianhua; (3) Zinc oxide: National Pharmaceutical Reagent; (4) Zinc borate: Jinan Taixing; (5) PTFE-based anti-dripping agent: Guangzhou Entropy Energy; (6) Polyethylene (LDPE): 2426, Yangzi Petrochemical; (7) EVA: V1803 (VA content 18%), Xinjiang Tianli High-tech Petrochemical Co., Ltd.; (8) Antioxidant, 1010, BASF; (9) Antioxidant, 168, BASF; (10) Silicone, Zhonglan Chenguang; (11) PPO, Bluestar Chemical; (12) Flame retardant system based on APP, AP750, Clariant; (13) Aluminum methyl phosphate (self-made); Preparation process: dimethyl methyl phosphate and aluminum trichloride were reacted at 120°C under vacuum for 8 hours to obtain aluminum methyl phosphate. Example 1
[0022] When flame-retardant compound systems are applied to vinyl polymers, the performance of the flame retardants is investigated according to the following steps and test methods.
[0023] Blending of halogen-free flame retardant systems Add the pre-weighed components of the flame-retardant compound system and other additives according to the formula to the high-speed mixer, start the high-speed mixer, stir for 10 minutes to complete the mixing of the halogen-free flame-retardant system, and then discharge the material.
[0024] Extrusion granulation of materials Set the temperatures of each zone of the twin-screw extruder to the preset temperatures. After the temperatures stabilize for 20 minutes, add the vinyl polymer to the hopper. Add the flame retardant powder through the powder feeding port. Start the main extruder and feeder to complete the material extrusion granulation. The granulated material is then conveyed into a silo via a pneumatic conveying system and dried.
[0025] Application and Testing of Materials The dried material is injection molded into standard samples according to various testing standards using an injection molding machine, and then the relevant material properties are tested. The following performance indicators are the main focus: Flame retardancy: Tested according to UL94 V0 standard: 5 samples are tested, each sample is ignited twice; each ignition lasts 10 seconds, then the flame is removed, and the afterflame time t1 and t2 are recorded. The standard stipulates that if the sample extinguishes within 10 seconds of being removed from the flame (i.e., afterflame time does not exceed 10 seconds), and the total afterflame time of the 10 ignitions for the 5 samples does not exceed 50 seconds, and the sample does not drip during ignition, and if the sample does not burn completely, there should be no smoldering without flame for more than 30 seconds after ignition, then the V0 standard is met, the flame retardancy test is passed, and it is recorded as PASS; otherwise, the flame retardancy test is failed and recorded as FAIL. In the case of PASS, the relative difference in flame retardancy performance can be distinguished by the total afterflame time; the shorter the time, the better the flame retardancy performance. If the flame retardant sample burns completely without extinguishing, it is recorded as not extinguishing; if the flame retardant sample does not burn completely but the total afterflame time is greater than 50 seconds, it is recorded as >50 seconds. Generally, the thinner the test piece, the more difficult it is to retard flames, and the longer the flame-retardant time will be.
[0026] Migration resistance test: The prepared flame-retardant vinyl polymer sample was placed in a constant temperature and humidity chamber, with the temperature set at 85℃ and the relative humidity at 85%. The surface condition of the sample was visually observed after 168 hours.
[0027] 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.
[0028] The materials and proportions in Example 1 are shown in Table 1, and the material test results are shown in Table 1. Example 2
[0029] The implementation process was the same as in Example 1, except that the ratio of aluminum methyl phosphate and piperazine pyrophosphate was changed while keeping the total amount of the flame-retardant compound system constant. The materials and proportions in Example 2 are shown in Table 1, and the material test results are also shown in Table 1. Example 3
[0030] The implementation process was the same as in Example 1, except that the ratio of aluminum methyl phosphate and piperazine pyrophosphate was changed while keeping the total amount of the flame-retardant compound system constant. The materials and proportions in Example 3 are shown in Table 1, and the material test results are also shown in Table 1. Example 4
[0031] The implementation process was the same as in Example 1, except that melamine pyrophosphate was added to the flame retardant component while keeping the total amount of the flame retardant compound system unchanged. The materials and proportions in Example 4 are shown in Table 1, and the material test results are also shown in Table 1.
[0032] Example 5 The implementation process is the same as in Example 4, except that zinc oxide is added to the flame-retardant component while keeping the total amount of the flame-retardant compound system unchanged. The materials and proportions in Example 5 are shown in Table 1, and the material test results are also shown in Table 1. Example 6
[0033] The implementation process is the same as in Example 5, except that a PTFE-based anti-dripping agent is added to the flame-retardant component while keeping the total amount of the flame-retardant compound system unchanged. The materials and proportions in Example 6 are shown in Table 1, and the material test results are also shown in Table 1. Example 7
[0034] The implementation process was the same as in Example 6, except that the ratio of aluminum methyl phosphate, piperazine pyrophosphate, and melamine pyrophosphate was changed while keeping the total amount of the flame-retardant compound system constant. The materials and proportions in Example 7 are shown in Table 1, and the material test results are also shown in Table 1. Example 8
[0035] The implementation process was the same as in Example 6, except that PPO was added to the flame retardant component, the proportion of aluminum methyl phosphate remained unchanged, and the proportions of piperazine pyrophosphate and melamine pyrophosphate were changed, while the total amount of the flame retardant compound system remained unchanged. The materials and proportions in Example 8 are shown in Table 1, and the material test results are also shown in Table 1.
[0036] Table 1 shows the material proportions and test results of the materials obtained in Examples 1-8. In summary, Examples 1-3 demonstrate that piperazine pyrophosphate and aluminum methyl phosphate exhibit good synergy over a wide range, achieving a UL94-V0 flame retardant rating for PE and EVA composites with a total addition of 30 parts. Examples 3-8 further show that introducing other components into the piperazine pyrophosphate and aluminum methyl phosphate system can further improve flame retardancy and shorten the flame delay time. These systems also exhibit good mechanical properties and migration characteristics.
[0037] Comparative Example 1 The implementation process is the same as in Example 1, except that aluminum methyl phosphate is not used and the total amount of the flame retardant compound system remains unchanged. The materials and proportions in Comparative Example 1 are shown in Table 2, and the material test results are shown in Table 2.
[0038] Comparative Example 2 The implementation process is the same as in Example 1, except that piperazine pyrophosphate is not used and the total amount of flame retardant compound system remains unchanged. The materials and proportions in Comparative Example 2 are shown in Table 2, and the material test results are shown in Table 2.
[0039] Comparative Example 3 The implementation process was the same as in Example 1, except that aluminum methyl phosphate accounted for 66.7% of the flame-retardant compound system. The materials and proportions in Comparative Example 3 are shown in Table 2, and the material test results are also shown in Table 2.
[0040] Comparative Example 4 The implementation process is the same as in Example 4, except that aluminum methyl phosphate is not used and the total amount of the flame retardant compound system remains unchanged. The materials and proportions in Comparative Example 4 are shown in Table 2, and the material test results are shown in Table 2.
[0041] Comparative Example 5 The implementation process is the same as in Example 5, except that aluminum methyl phosphate is not used and the total amount of the flame retardant compound system remains unchanged. The materials and proportions in Comparative Example 5 are shown in Table 2, and the material test results are shown in Table 2.
[0042] Comparative Example 6 The implementation process is the same as in Example 6, except that aluminum methyl phosphate is not used and the total amount of the flame retardant compound system remains unchanged. The materials and proportions in Comparative Example 6 are shown in Table 2, and the material test results are shown in Table 2.
[0043] Comparative Example 7 The implementation process is the same as in Example 8, except that aluminum methyl phosphate is not used and the total amount of the flame retardant compound system remains unchanged. The materials and proportions in Comparative Example 7 are shown in Table 2, and the material test results are shown in Table 2.
[0044] Comparative Example 8 The implementation process was the same as in Example 1, except that aluminum methyl phosphate was not used, and the amounts of piperazine pyrophosphate and melamine pyrophosphate were increased to allow the material to pass UL94 V0 flame retardancy. The materials and proportions in Comparative Example 8 are shown in Table 2, and the test results of the obtained materials are also shown in Table 2.
[0045] Comparative Example 9 The implementation process was the same as in Example 1, except that the flame-retardant compound system was replaced with AP750 to ensure the material passed UL94 V0 flame retardancy. The materials and proportions in Comparative Example 9 are shown in Table 2, and the resulting material test results are also shown in Table 2.
[0046] Table 2 shows the material proportions and test results of the materials obtained in Comparative Examples 1-9. In summary, based on the results of Examples 1-8 and Comparative Examples 1-9, it can be seen that piperazine pyrophosphate or aluminum methyl phosphate alone exhibits poor flame retardant properties, while the composite system of piperazine pyrophosphate and aluminum methyl phosphate shows better flame retardant properties. Similarly, aluminum methyl phosphate also enhances the flame retardant properties of the piperazine pyrophosphate and melamine pyrophosphate system, while also providing good mechanical properties and migration resistance. Furthermore, compared to commonly used APP-based flame retardant systems in this field, the composition of this application has lower addition amounts, better migration and exudation resistance, and higher mechanical properties.
[0047] The above descriptions are merely embodiments of the present invention, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.
Claims
1. A halogen-free flame-retardant compound system for vinyl polymers enhanced with alkyl phosphate metal salts, characterized in that, By weight percentage, its composition includes: 40 - 99 wt% of piperazine pyrophosphate; 1 - 60 wt% of alkyl phosphate metal salt; 0 - 60 wt% of melamine derivative; 0 - 10% of zinc-containing compound; 0 - 1% of PTFE-based anti-dripping agent; 0 - 20% of charring agent. The melamine derivative includes at least one of melamine pyrophosphate, melamine polyphosphate, melamine cyanurate, and melamine condensate; the charring agent is a hydroxyl-containing organic compound or an oxygen-containing polymer with a benzene ring.
2. The halogen-free flame-retardant compound system for vinyl polymers enhanced with alkyl phosphate metal salts according to claim 1, characterized in that, The average particle size of the alkyl phosphate metal salt is 1 < D50 < 40 μm, and it has the following structural formula: Where R1 and R2 are linear aliphatic saturated hydrocarbon groups and unsaturated hydrocarbon groups, and can also be aromatic groups, which can be the same or different; M is a metal element.
3. The halogen-free flame-retardant compound system for vinyl polymers enhanced with alkyl phosphate metal salts according to claim 2, characterized in that, The alkyl phosphate metal salt is methyl methyl phosphate aluminum.
4. The halogen-free flame-retardant compound system for vinyl polymers enhanced with alkyl phosphate metal salts according to claim 1, characterized in that, The average particle size of the piperazine pyrophosphate is 1 < D50 < 40 μm.
5. The halogen-free flame-retardant compound system for vinyl polymers enhanced with alkyl phosphate metal salts according to claim 1, characterized in that, The average particle size of the melamine derivative is 1 < D50 < 40 μm.
6. The halogen-free flame-retardant compound system for vinyl polymers enhanced with alkyl phosphate metal salts according to claim 1, characterized in that, The zinc-containing compound includes zinc oxide, zinc borate or zinc stannate.
7. The halogen-free flame-retardant compound system for vinyl polymers enhanced with alkyl phosphate metal salts according to claim 1, characterized in that, The PTFE-based anti-dripping agent is modified core-shell polytetrafluoroethylene.
8. The application of a halogen-free flame-retardant compound system for vinyl polymers enhanced with alkyl phosphate metal salts, characterized in that, The flame retardant compounding system is applied to vinyl polymers, and its addition amount is 10 - 60 wt%.
9. The application of the halogen-free flame-retardant compound system for vinyl polymers enhanced with alkyl phosphate metal salts according to claim 8, characterized in that, The vinyl polymer includes polyethylene, EVA or their blends.