High glowing filament flame-retardant modified PA material and preparation method thereof

Abstract

The invention discloses a high glowing filament flame-retardant modified PA material and a preparation method thereof. The high glowing filament flame-retardant modified PA material comprises PA resin, a halogen-free flame retardant, a flame-retardant synergist, a glowing filament synergist compound, magnesium hydroxide, a coupling agent, a flexibilizer, an antioxidant, a lubricant and a nucleating agent. By adding the MCA flame retardant, the flame retardant synergist and the treated glowing filament synergist compound, the flame retardant grade UL94 V0 of the material can be met, the glowing filament ignition temperature and glowing filament stability of the material are improved, and the latest environmental protection requirement is met; by adding the polyester nucleating agent, the thermal crystallization temperature is effectively increased in the melt cooling crystallization process, the crystallization speed is increased, and the film sticking problem is solved; the obtained product has the advantages of high mechanical property, good fireproof performance, excellent processability, good dimensional stability and good product surface glossiness, can meet the requirement of a 750 DEG C glowing filament for no ignition in the whole process, and meets the market demand of a PA modified material.

Description

Technical Field

[0001] The present invention relates to the technical field of flame retardant materials, and in particular to a high glow-wire flame retardant modified PA material and a preparation method thereof. Background Art

[0002] Polyamide (PA), also known as nylon, is an engineering plastic with excellent overall performance, featuring high mechanical strength, strong fatigue resistance, good heat and wear resistance, strong corrosion resistance, excellent electrical properties, and easy molding and processing. With the development of the electronics and new energy industries, polyamide has a wide range of applications in engineering plastics, with the high glow-wire flame-retardant PA6 / 66 and modified materials emerging as the most suitable materials for electronic and electrical components.

[0003] Current flame retardants using cyanuric acid tripolyamine or red phosphorus combined with triphenyl phosphate do not meet EU environmental requirements. Inorganic flame retardants, such as decabromophenol and antimony, also face limitations in many applications. Furthermore, red phosphorus is red, making it unsuitable for use in light-colored materials. Its application range is limited, and it is prone to ignition at high temperatures, making it unsafe to use.

[0004] Patent CN102146207 discloses a highly glow-wire flame-retardant PA6 / 66 and its production process. The product comprises a PA6 / 66 bromine-antimony composite flame retardant, a toughening agent, a flame retardant synergist, an inorganic filler, a stabilizer, a lubricant, an antioxidant, and a nucleating agent. This technical solution primarily utilizes bromine-antimony combined with synergists such as MPP and triphenyl phosphate to achieve flame retardancy and increase the glow-wire temperature. However, the addition of triphenyl phosphate does not meet the requirements of the latest SVHC environmental control list for 2024.

[0005] Patent CN109705567A discloses a flame-retardant reinforced PA material with a high glow-wire temperature. The material comprises PA6 / 66, a flame retardant, a toughening agent, and additives (antioxidants, lubricants, and nucleating agents). This technical solution achieves flame retardancy and increases the glow-wire temperature by adding a large amount of a bromine-antimony compound or red phosphorus flame retardant. However, this technical solution uses decabromodiphenyl ethane, which is prohibited under Canada's environmental regulations, the Prohibition of Certain Toxic Substances Regulations 2022, and therefore fails to meet market demands for environmentally friendly use. Furthermore, red phosphorus is used as a flame retardant, but it easily ignites at high temperatures, posing a significant safety hazard during production. Furthermore, red phosphorus is dark red in color and cannot be used in light-colored materials, limiting its application range.

[0006] Patent NC116622221A discloses a PA resin composition with a high glow-wire flammability index and its preparation method. The PA resin composition is composed of the following raw materials in percentage by weight: 50%-75% polyamide (PA) resin, 3.0% toughening agent, 15-18% brominated flame retardant, 2.0-5.0% phosphorus-based flame retardant, 3.0-4.0% synergistic flame retardant, 0.5% antioxidant, 0-0.5% pigment, and 20-30% glass fiber. This achieves flame retardancy and increases the glow-wire temperature. This technical solution incorporates at least one of aluminum hypophosphite, ammonium polyphosphate, or triphenyl phosphate as the phosphorus-based flame retardant. However, the addition of triphenyl phosphate does not meet the requirements of the latest SVHC environmental control list for 2024.

[0007] Therefore, the development of high glow-wire flame-retardant PA6 / 66 modified materials meets the requirements of high glow-wire, high performance, and excellent fire resistance, meets the latest environmental protection control requirements, and has broad application prospects. Summary of the Invention

[0008] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a high glow-wire flame retardant modified PA material and a preparation method thereof.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions: A high glow-wire flame-retardant modified PA material, the raw materials of which comprise the following components by weight percentage (%): PA resin, 66-76%; Halogen-free flame retardant, 16-18%; Flame retardant synergist, 2-5%; Glow-wire synergist compound, 1-5%; magnesium hydroxide, 2-5%; coupling agent, 0.2-0.5%; Toughener, 1-3%; Antioxidants, 0.2-1%; Lubricant, 0.2-1%; Nucleating agent, 0.1-0.5%.

[0010] Preferably, the intrinsic viscosity of the PA resin is 2.4-2.7.

[0011] Preferably, the halogen-free flame retardant is a phosphorus-nitrogen based MCA flame retardant that does not contain red phosphorus.

[0012] Preferably, the flame retardant synergist is melamine, which decomposes under heat to produce non-combustible gases such as NH3, which dilute oxygen and combustible gases; polyammonium phosphate and melamine react to form an expanded carbon layer (PNC structure) to isolate heat and oxygen.

[0013] Preferably, the glow-wire synergist compound is a compound of boehmite, 1,3-phenylene tetrakis(2,6-dimethylphenyl)phosphate (condensation polymer) and barium dihydrogen phosphate, with a compounding ratio of 1:1:2-1:2:3, wherein the boehmite is nano-boehmite with an average particle size of 10-20 nm.

[0014] Preferably, the toughening agent is one or more of POE grafted maleic anhydride, ethylene-methyl acrylate-glycidyl methacrylate and ethylene-butyl acrylate-glycidyl methacrylate.

[0015] Preferably, the lubricant is one or more of PETS, 540A, and silicone powder.

[0016] Preferably, the nucleating agent is polyester nucleating agent RW330, and the purchasing company is Fengtian Chemical Co., Ltd.

[0017] Preferably, the antioxidant is one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076.

[0018] Preferably, the magnesium hydroxide is from Yifeng Company, model DR-1000.

[0019] Preferably, the coupling agent can be KH550 or KH560.

[0020] The present invention also provides a method for preparing the aforementioned high glow-wire flame-retardant modified PA material, comprising the following steps: 1) Boehmite, tetrakis(2,6-dimethylphenyl)1,3-phenylene phosphate (condensation polymer), and barium dihydrogen phosphate were mixed uniformly in a powder grinder for 5 minutes to prepare a pretreated glow-wire synergist compound A; 2) PA resin, MCA flame retardant, flame retardant synergist, pretreated glow-wire synergist compound A, toughening agent, coupling agent, antioxidant, lubricant, and nucleating agent are placed in a blender and mixed and stirred to obtain mixture B.

[0021] 3) The mixed B is fed into a twin-screw extruder and heated until melted and extruded to obtain the modified PA material.

[0022] Preferably, in 3), the melt extrusion temperature is 200-240° C., and the screw speed is 300-500 r / min.

[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention, by adding an MCA flame retardant, a flame retardant synergist, and a treated glow-wire synergist compound, can meet the material's UL94 V0 flame retardancy rating, and improve the material's glow-wire ignition temperature and glow-wire stability, meeting the latest environmental protection requirements.

[0024] 2. The present invention effectively increases the thermal crystallization temperature during the melt cooling crystallization process by adding a polyester nucleating agent, accelerates the crystallization rate, solves the sticking problem, improves the dimensional stability of the product, reduces the post-shrinkage of the product, and improves the surface gloss of the product.

[0025] 3. The high glow-wire flame-retardant PA modified material prepared by the present invention has high mechanical properties, good fire resistance, can meet the requirement of no ignition of the glow-wire at 750°C throughout the entire process, excellent processing performance (non-stick to the mold), good dimensional stability, and good surface gloss of the product. It meets the market demand for PA modified materials and meets the latest environmental protection control requirements in the market, and has broad market application prospects.

[0026] 4. The production process of the present invention is simple, highly operable, and easy to promote and apply on a large scale, thereby producing a highly glow-wire flame-retardant PA modified material. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0028] 1. Inventive Concept: Existing technologies for increasing the glow-wire temperature of PA modified materials include: adding bromine antimony to MPP, triphenyl phosphate, and other synergists to achieve flame retardancy and increase the glow-wire temperature. However, the addition of triphenyl phosphate does not meet the requirements of the latest SVHC environmental control list for 2024. Large amounts of decabromodiphenyl ethane (DBPE) and antimony powder compounds or red phosphorus flame retardants can also achieve flame retardancy and increase the glow-wire temperature. However, this technology uses decabromodiphenyl ethane, which is prohibited under Canada's environmental regulations, the Prohibition of Certain Toxic Substances Regulations 2022, and therefore does not meet market demand for environmentally friendly use. Furthermore, red phosphorus flame retardant easily ignites at high temperatures, posing a significant safety hazard during production. Its deep red color prevents its application in light-colored materials, limiting its application range. The addition of at least one phosphorus-based flame retardant, selected from aluminum hypophosphite, ammonium polyphosphate, or triphenyl phosphate, significantly decreases the mechanical properties of PA materials as the amount of aluminum hypophosphite or ammonium polyphosphate increases. Furthermore, the addition of triphenyl phosphate does not meet the requirements of the latest SVHC environmental control list for 2024.

[0029] By incorporating a nitrogen-based halogen-free flame retardant (MCA), a flame retardant synergist, and a glow-wire synergist compound treated with magnesium hydroxide, this material meets the UL94 V0 flame retardancy rating and improves both the glow-wire ignition temperature and glow-wire stability, meeting the latest environmental protection requirements. The addition of a nucleating agent, antioxidant, lubricant, coupling agent, and compatibilizer effectively raises the crystallization temperature and speeds up crystallization during melt cooling and crystallization, addressing the problem of sticking films. It also improves the dimensional stability of the finished product, reduces post-process shrinkage, and enhances the surface gloss of the finished product.

[0030] The present invention relates to the technical field of highly glow-wire flame-retardant PA modified materials, specifically to a highly glow-wire flame-retardant PA modified material and its preparation method. The raw materials, by weight, comprise the following components: 66-76% PA resin, 16-18% halogen-free flame retardant; 2-5% flame retardant synergist; 1-5% glow-wire synergist compound; 2%-5% magnesium hydroxide; 0.2-0.5% coupling agent; 1-3% toughening agent; 0.2-1% antioxidant; 0.2-1% lubricant; and 0.1-0.5% nucleating agent. The highly glow-wire flame-retardant, reinforced, high-performance PA modified material prepared by this invention exhibits high mechanical properties, excellent fire resistance, and the ability to withstand a 750°C glow-wire fire. It also exhibits excellent processability (non-sticking to molds), good dimensional stability, and a high surface gloss on the finished product. This material meets market demand for PA modified materials and the latest environmental regulations, and has broad market application prospects.

[0031] 2. Formulation screening: 1. Formulation range A high glow-wire flame-retardant modified PA material, the raw materials of which comprise the following components by weight percentage (%): PA resin, 66-76%; Halogen-free flame retardant, 16-18%; Flame retardant synergist, 2-5%; Glow-wire synergist compound, 1-5%; magnesium hydroxide, 2-5%; coupling agent, 0.2-0.5%; Toughener, 1-3%; Antioxidants, 0.2-1%; Lubricant, 0.2-1%; Nucleating agent, 0.1-0.5%.

[0032] The intrinsic viscosity of PA resin is 2.4-2.7. The halogen-free flame retardant is a phosphorus-nitrogen based MCA flame retardant that does not contain red phosphorus.

[0033] The flame retardant synergist is melamine, which decomposes when heated to produce non-combustible gases such as NH3, which dilutes oxygen and combustible gases; polyammonium phosphate and melamine react to form an expanded carbon layer (PNC structure) to isolate heat and oxygen.

[0034] The glow-wire synergist compound is a compound of boehmite, 1,3-phenylene tetrakis(2,6-dimethylphenyl)phosphate (condensation polymer) and barium dihydrogen phosphate, and the compounding ratio of the three is 1:1:2-1:2:3, wherein the boehmite is nano-boehmite with an average particle size of 10-20 nm.

[0035] The toughening agent is one or more of POE grafted maleic anhydride, ethylene-methyl acrylate-glycidyl methacrylate and ethylene-butyl acrylate-glycidyl methacrylate.

[0036] The lubricant is one or more of PETS, 540A and silicone powder.

[0037] The nucleating agent is polyester nucleating agent RW330, and the company is Fengtian Chemical Co., Ltd.

[0038] The antioxidant is one or more of antioxidant 1010, antioxidant 168, and antioxidant 1076.

[0039] Magnesium hydroxide was purchased from Yifeng Company, model DR-1000.

[0040] The coupling agent is KH550 or KH560.

[0041] 2. Formulation screening According to the above range, the formula shown in Table 1 is designed: Table 1. Example formulations Among them, the toughening agent of Examples 1 and 2 is POE grafted maleic anhydride, Example 3 is ethylene-methyl acrylate-glycidyl methacrylate, and Example 4 is ethylene-butyl acrylate-glycidyl methacrylate; The antioxidant content of Examples 1 and 2 was 1010, that of Example 3 was 168, and that of Example 4 was 1076; The lubricant in Examples 1 and 2 is PETS, in Example 3 is 540A, and in Example 4 is silicone powder; the coupling agent in Examples 1 and 2 is KH550, and the coupling agent in Examples 3 and 4 is KH560.

[0042] The comparative samples shown in Table 2 were also designed: Table 2. Comparative Example Formula It should be noted that in Table 2, glow-wire synergist a refers to the glow-wire synergist compound without boehmite; Comparative Examples 1-3 used glow-wire synergist a; glow-wire synergist b refers to the glow-wire synergist compound without tetrakis(2,6-dimethylphenyl)1,3-phenylene phosphate (condensation product); Comparative Examples 4-6 used glow-wire synergist b; glow-wire synergist c refers to the glow-wire synergist compound without barium dihydrogen phosphate; Comparative Examples 7-8 used glow-wire synergist c; in Comparative Example 9, boehmite, tetrakis(2,6-dimethylphenyl)1,3-phenylene phosphate (condensation product), and barium dihydrogen phosphate were not pretreated. When the amount of glow-wire synergist compound added is relatively low, the glow-wire temperature is relatively low and the tensile strength is relatively high. When the amount of glow-wire synergist compound added is appropriate, the glow-wire temperature is relatively high, but the tensile strength is relatively low.

[0043] 3. Preparation process: 1) Boehmite, tetrakis(2,6-dimethylphenyl)1,3-phenylene phosphate (condensation polymer), and barium dihydrogen phosphate were mixed uniformly in a powder grinder for 5 minutes to prepare a pretreated glow-wire synergist compound A; 2) The PA resin, MCA flame retardant, flame retardant synergist, pretreated glow-wire synergist compound A, magnesium hydroxide, toughening agent, antioxidant, lubricant, and nucleating agent are placed in a blender and mixed and stirred to obtain a mixture B.

[0044] 3) The mixture B and the glass fiber are fed into a twin-screw extruder, heated until melted and extruded to obtain the high glow-wire flame-retardant reinforced high-performance PA modified material.

[0045] 3) The melt extrusion temperature is 180-240°C and the screw speed is 300-500 r / min.

[0046] 3. Performance test: 1. Performance results: Table 3. Example product performance Table 4. Comparative Example Product Performance 1 Table 5. Comparative Example Product Performance II 2. Data Analysis: Data from Comparative Examples 1-8 and Examples 1-3 demonstrate that the addition of the glow-wire synergist compound can cause a decrease in material performance. While the impact is minimal at low addition levels, it significantly decreases when added above 5%. However, the glow-wire synergist compound significantly improves the glow-wire properties of the material, helping to increase the glow-wire temperature and improve the stability of the finished glow-wire. Therefore, the compound should be added at an appropriate ratio to meet the material's performance requirements. Furthermore, pretreatment with the glow-wire synergist compound can significantly improve the stability of the finished glow-wire.

[0047] The data from Comparative Examples 6-8 show that while the addition of boehmite degrades material properties, it significantly improves the glow-wire temperature of the product. Tetrakis(2,6-dimethylphenyl)1,3-phenylenephosphate (condensation product) and barium dihydrogen phosphate have negligible effects on material properties, effectively improving the glow-wire temperature and stability of the product.

[0048] The data from Comparative Example 9 and Example 4 demonstrate that the addition of a nucleating agent significantly improves mold sticking and the surface of the finished product. The nucleating agent can be evenly dispersed into the polymer melt, providing and generating tiny crystal nuclei, forming a uniform and dense crystal structure, and accelerating PA crystallization. The nucleating efficiency is extremely high, with minimal molecular weight reduction. During the melt cooling crystallization process, the crystallization temperature is effectively raised, accelerating the crystallization rate, significantly improving mold sticking and the finished product's surface.

[0049] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A high glow-wire flame retardant modified PA material, characterized in that: The raw materials include the following components by weight percentage: PA resin, 66-76%; Halogen-free flame retardant, 16-18%; Flame retardant synergist, 2-5%; Glow-wire synergist compound, 1-5%; magnesium hydroxide, 2-5%; coupling agent, 0.2-0.5%; Toughener, 1-3%; Antioxidants, 0.2-1%; Lubricant, 0.2-1%; Nucleating agent, 0.1-0.5%.

2. The high glow-wire flame-retardant modified PA material according to claim 1, characterized in that: The intrinsic viscosity of the PA resin is 2.4-2.

7.

3. The high glow-wire flame-retardant modified PA material according to claim 1, characterized in that: The halogen-free flame retardant is a phosphorus-nitrogen based MCA flame retardant.

4. The high glow-wire flame-retardant modified PA material according to claim 1, characterized in that: The flame retardant synergist is melamine.

5. The high glow-wire flame-retardant modified PA material according to claim 1, characterized in that: The glow-wire synergist compound is a compound of boehmite, 1,3-phenylene tetrakis(2,6-dimethylphenyl)phosphate (condensation polymer) and barium dihydrogen phosphate, with a compounding ratio of 1:1:2-1:2:

3. The boehmite is nano-boehmite with an average particle size of 10-20 nm.

6. The high glow-wire flame-retardant modified PA material according to claim 1, characterized in that: The toughening agent is one or more of POE grafted maleic anhydride, ethylene-methyl acrylate-glycidyl methacrylate and ethylene-butyl acrylate-glycidyl methacrylate.

7. The high glow-wire flame-retardant modified PA material according to claim 1, characterized in that: The lubricant is one or more of PETS, 540A and silicone powder.

8. The high glow-wire flame-retardant modified PA material according to claim 1, characterized in that: The nucleating agent is a polyester nucleating agent.

9. The method for preparing a highly glow-wire flame-retardant modified PA material according to any one of claims 1 to 8, characterized in that: 1) Boehmite, tetrakis(2,6-dimethylphenyl)1,3-phenylene phosphate (condensation polymer), and barium dihydrogen phosphate were mixed uniformly in a powder grinder for 5 minutes to prepare a pretreated glow-wire synergist compound A; 2) The PA resin, halogen-free flame retardant, flame retardant synergist, pretreated glow-wire synergist compound A, toughening agent, coupling agent, antioxidant, lubricant, and nucleating agent are placed in a blender and mixed uniformly to prepare a mixture B. 3) The mixture B is fed into a twin-screw extruder, heated until melted and extruded, thereby obtaining the high glow-wire flame-retardant reinforced high-performance modified PA material.

10. The method for preparing a high glow-wire flame-retardant modified PA material according to claim 9, characterized in that: In the above 3), the melt extrusion temperature is 200-240° C., and the screw speed is 300-500 r / min.

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