High-temperature-resistant flame-retardant polyester fiber foaming material and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant flame-retardant polyester fiber foaming material and a preparation method thereof, and relates to the technical field of foaming material preparation, and the preparation method comprises the following steps: putting a polyester fiber matrix into an air dry oven to prepare a flame-retardant foaming premix; adding the pretreated polyester fiber matrix, the flame-retardant foaming premix, the cross-linking agent and the functional additive into a double-screw mixer to prepare a mixed material; adding the mixed material into a mould pressing foaming machine to obtain a primary foaming forming material; and demolding the primary foaming molding material, naturally cooling to room temperature, carrying out surface finishing to remove burrs, then carrying out high-temperature aging treatment, and finally carrying out flame retardant property detection to obtain a finished product of the high-temperature-resistant flame-retardant polyester fiber foaming material after the finished product is qualified. The polyester fiber composite matrix, the composite foaming agent, the intumescent flame retardant and the high-temperature-resistant modifier are compounded, a five-step preparation process is optimized, and multi-link monitoring and regulation are added, so that functional integration of high-temperature resistance, flame retardance and balanced mechanical properties of the material is realized.

Description

Technical Field

[0001] This invention relates to the field of foam material preparation technology, specifically to a high-temperature resistant flame-retardant polyester fiber foam material and its preparation method. Background Technology

[0002] Polyester fiber foam materials are widely used in building insulation, electronic and electrical packaging, and transportation due to their advantages such as lightweight, thermal insulation, sound insulation, and balanced mechanical properties. However, traditional polyester fiber foam materials have significant performance shortcomings, limiting their application in special scenarios such as high temperature and high risk environments. On the one hand, its high-temperature resistance is poor, and it is prone to softening, deformation, and even thermal degradation in environments above 120℃, leading to the destruction of structural integrity. On the other hand, its flame retardant performance is insufficient, with most products having an oxygen index below 28%, classifying them as flammable or combustible materials. When burning, they easily release toxic and harmful gases such as carbon monoxide and benzene compounds, causing secondary safety hazards. To improve these defects, existing technologies mostly use single flame retardants or high-temperature resistant fillers for modification, but these generally suffer from poor compatibility and uneven dispersion. For example, while using inorganic flame retardants alone can improve flame retardancy, it can lead to a decrease in the mechanical properties of the material and a reduction in the foaming ratio. Using a single high-temperature resistant modifier makes it difficult to balance high-temperature stability and processing fluidity. At the same time, existing preparation processes suffer from problems such as rough parameter control and missing pretreatment steps. For example, incomplete removal of moisture from raw materials can easily lead to bubble rupture during foaming, and uneven mixing can cause fluctuations in product performance, ultimately affecting the consistency and reliability of the product. In addition, some modification processes require the introduction of toxic and harmful additives, which do not meet environmental protection requirements, and the processes are complex and costly, which is not conducive to industrial promotion.

[0003] Therefore, developing a polyester fiber foam material with excellent high-temperature resistance, stable flame retardant effect, controllable process and environmental protection has become an urgent technical problem to be solved in this field. Summary of the Invention

[0004] To solve the above-mentioned technical problems, a high-temperature resistant flame-retardant polyester fiber foam material and its preparation method are provided. This technical solution solves the above-mentioned problems.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A high-temperature resistant and flame-retardant polyester fiber foam material, characterized in that the foam material comprises: 60-80 parts of polyester fiber matrix, 5-12 parts of composite foaming agent, 8-15 parts of high-efficiency flame retardant, 3-8 parts of high-temperature resistant modifier, 1-4 parts of crosslinking agent, and 2-6 parts of functional additives.

[0006] Preferably, the composite foaming agent is a compound system of azodicarbonamide and sodium bicarbonate with a mass ratio of 4:1 to 3:1, the polyester fiber matrix is ​​a composite matrix of polyethylene terephthalate and polybutylene terephthalate, and the high-temperature resistant modifier is a compound system of nano-aluminum nitride and hollow glass microspheres.

[0007] Preferably, the high-efficiency flame retardant is an intumescent flame retardant, which is compounded from ammonium polyphosphate, pentaerythritol, and melamine in a mass ratio of 5:2:3. The crosslinking agent is dicumyl peroxide. The functional additives include antioxidants, lubricants, and nucleating agents in a mass ratio of 3:2:1. The antioxidant is a compound system of hindered phenol 1010 and phosphite 168, the lubricant is zinc stearate, and the nucleating agent is talc.

[0008] A method for preparing a high-temperature resistant and flame-retardant polyester fiber foam material includes: S1. Raw material pretreatment: Place the polyester fiber matrix in a forced-air drying oven, control the temperature at 80-100°C, and treat for 2-4 hours to remove the internal moisture of the material. At the same time, mix the composite foaming agent, high-efficiency flame retardant and high-temperature resistant modifier in a mass ratio of 3:5:2, add it to a high-speed mixer, rotate at 250-350 rpm, and mix for 15-25 minutes to prepare a flame-retardant foam premix. S2. Mixing and stirring: Add the pretreated polyester fiber matrix, flame-retardant foam premix, crosslinking agent and functional additives to a twin-screw mixer. The mixing temperature is controlled in three zones: 130-140°C, 145-155°C, and 150-160°C. The screw speed is 400-600 rpm. After mixing, the mixture is discharged to form a mixed material. S3. Foaming molding: Add the mixture to a molding foaming machine, with a molding temperature of 160-180°C, a molding pressure of 8-12MPa, a holding time of 15-25 minutes, and control the foaming ratio to 3-5 times to obtain the preliminary foamed molding material. S4. Post-processing: After the initial foamed molding material is demolded, it is naturally cooled to room temperature. The surface is trimmed to remove burrs, followed by high-temperature aging treatment at 120-140°C for 24-36 hours. Finally, flame retardant performance is tested. If it passes the test, the finished high-temperature flame-retardant polyester fiber foam material is obtained.

[0009] Preferably, S1 specifically includes: After drying, the moisture content of the polyester fiber matrix is ​​tested to ensure that the moisture content is ≤0.5%. Subsequently, a flame retardant activation treatment step is introduced, in which the flame retardant foamed premix is ​​placed in an ultraviolet irradiation device with an irradiation power of 30-50W and an irradiation time of 8-12 minutes to improve the dispersibility of the flame retardant. In the preparation of flame-retardant foamed premix, after adding 0.5-1.0 parts of dispersant stearamide, a particle size analysis and monitoring step is added. The particle size distribution of the premix is ​​detected in real time by a laser particle size analyzer, and the particle size is controlled within 50-150μm.

[0010] Preferably, the characteristic of step S2 is that it specifically includes: Before operating the twin-screw mixer, the barrel is first cleaned by purging with high-pressure nitrogen to remove residual impurities, and then high-temperature resistant grease is applied. During the mixing process, a real-time monitoring step for melt flow rate is added. The melt flow rate is measured every 5 minutes by a melt flow rate meter, and the melt flow rate is controlled at 10-20 g / 10 min. When it deviates from the range, the screw speed and mixing temperature are adjusted. After the mixed materials are discharged, an appearance inspection is carried out to remove materials containing lumps and impurities. Qualified materials are sealed and packaged and stored in a dry environment.

[0011] Preferably, S3 specifically includes: Before molding, the mold should be preheated at a temperature of 120-140°C for 10-15 minutes to reduce temperature loss and thermal stress during molding. In the molding and foaming process, in addition to detecting pressure and temperature, the online monitoring system has added a real-time monitoring function for foaming ratio. It dynamically detects the foaming volume through volume measurement. When the foaming ratio deviates from the set range of ±0.3 times, it automatically adjusts the molding temperature and holding time. After foaming, the temperature is lowered using a gradient cooling method. First, the temperature is lowered to 120°C at a rate of 5°C / minute, and then naturally cooled to 80°C before demolding.

[0012] Preferably, in the online monitoring system, the data from the pressure sensor, temperature sensor, and foaming ratio detection device are transmitted to the central control system in real time. The system has a built-in parameter comparison and early warning module that compares the real-time data with standard parameters. When the deviation exceeds the set threshold, an audible and visual alarm is immediately issued and the process parameters are automatically adjusted. Meanwhile, the system automatically records the process parameters, test data and product number for each foaming molding process, forming a complete production quality traceability database. When the foaming ratio exceeds the standard twice in a row, the system will automatically stop the machine and prompt the user to check the activity of the foaming agent and the sealing of the mold.

[0013] Preferably, in step S4, the surface finishing is done using a grinding wheel grinder with a grinding speed of 1800-2200 revolutions per minute. A high-efficiency dust collection device is provided during the grinding process to avoid dust pollution and fiber scattering. During high-temperature aging treatment, a constant-temperature forced-air drying oven is used to control the relative humidity at 30%-40%. The integrity of the material's appearance is checked every 12 hours during the aging process. The flame retardant performance is detected by the oxygen index method, carried out according to the standard of GB / T2406.2—2009, and the oxygen index ≥ 32% is qualified.

[0014] Preferably, in S4, after high-temperature aging, a high-temperature resistance performance detection step is added. The sample is placed in a constant-temperature oven at 200°C for 2 hours, and after taking it out, its tensile strength retention rate ≥ 85% and mass loss rate ≤ 5% are detected; If the detection is unqualified, the sample is re-treated by high-temperature aging, and the aging time is extended by 8 - 12 hours, and then detected again. If it is still unqualified, it is determined as waste, recycled and re-crushed, and used as a raw material for blending, and the blending ratio does not exceed 10%.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention proposes to compound a polyester fiber composite matrix, a composite foaming agent, an intumescent flame retardant and a high-temperature resistant modifier, optimize the five-step preparation process and add multi-link monitoring and regulation to achieve the functional integration of high temperature resistance, flame retardancy and balanced mechanical properties of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a framework diagram of the preparation process of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments in the following description are only examples, and those skilled in the art can think of other obvious variations.

[0018] Example 1 (High-temperature resistant and high flame retardant type for building exterior walls) Raw material formula (based on a total mass of 100 parts) Polyester fiber matrix: polyethylene terephthalate (45 parts) + polybutylene terephthalate (30 parts), a total of 75 parts; Composite foaming agent: azodicarbonamide (8 parts) + sodium bicarbonate (2 parts), mass ratio 4:1, a total of 10 parts; High-efficiency flame retardant: ammonium polyphosphate (6 parts) + pentaerythritol (2.4 parts) + melamine (3.6 parts), mass ratio 5:2:3, a total of 12 parts; High-temperature resistant modifier: nano-aluminum nitride (4 parts, particle size 50 - 80nm) + hollow glass microspheres (2 parts, particle size 100 - 150μm), a total of 6 parts; Crosslinking agent: dicumyl peroxide (2 parts); Functional additives: hindered phenol 1010 (1.2 parts) + phosphite 168 (0.8 parts) + zinc stearate (0.8 parts) + talc (0.4 parts), antioxidant, lubricant and nucleating agent in a mass ratio of 3:2:1, totaling 3.2 parts; Preparation steps S1. Raw material drying: The polyester fiber matrix was placed in a constant temperature forced-air drying oven at 90℃ for 3 hours, and the moisture content was measured to be 0.3%. S2. Preparation of premix: The composite foaming agent, high-efficiency flame retardant and high-temperature resistant modifier are mixed in a mass ratio of 3:5:2 and added to a high-speed mixer. The mixture is stirred at 300 r / min for 20 minutes. 0.8 parts of dispersant stearamide are added. The particle size is monitored by laser particle size analysis and found to be 80-120 μm. The mixture is then activated by ultraviolet light irradiation (power 40W, time 10 minutes). S3. Mixing and granulation: The dried matrix, premix, crosslinking agent and functional additives are fed into a twin-screw mixing and granulating machine. The temperature is 135℃ in zone 1, 150℃ in zone 2 and 155℃ in zone 3. The screw speed is 500r / min. The mixture is extruded and granulated to obtain mixed particles with a particle size of 3-4mm. The melt flow rate is 15g / 10min. S4. Foaming molding: Preheat the mold to 130℃ for 12 minutes, add the mixed particles to the molding foaming machine, temperature 170℃, pressure 10MPa, hold pressure and foam for 20 minutes, foaming ratio 4 times, online monitoring shrinkage rate 3.5%, gradient cooling to 120℃ and then naturally cooling to 80℃ for demolding. S5. Post-processing optimization: Grinding wheel speed 2000r / min (with dust collection device), high temperature aging (130℃, humidity 35%, time 30 hours), flame retardant performance test (oxygen index 34%), new high temperature resistance test (200℃ heat preservation for 2 hours, tensile strength retention rate 88%, mass loss rate 3.2%).

[0019] Example 2 (Lightweight and High-Temperature Resistant Type for Electronic Device Packaging) Raw material formula (based on 100 parts by total mass) Polyester fiber matrix: polyethylene terephthalate (35 parts) + polybutylene terephthalate (25 parts), total 60 parts; Composite foaming agent: azodicarbonamide (6 parts) + sodium bicarbonate (3 parts), mass ratio 2:1, total 9 parts; High-efficiency flame retardant: ammonium polyphosphate (4 parts) + pentaerythritol (1.6 parts) + melamine (2.4 parts), mass ratio 5:2:3, total 8 parts; High-temperature resistant modifier: Nano aluminum nitride (3 parts, particle size 40-60nm) + hollow glass microspheres (3 parts, particle size 80-120μm), total 6 parts; Crosslinking agent: dicumyl peroxide (1 part); Functional additives: hindered phenol 1010 (0.9 parts) + phosphite 168 (0.6 parts) + zinc stearate (0.6 parts) + talc (0.3 parts); antioxidant, lubricant and nucleating agent in a mass ratio of 3:2:1, totaling 2.4 parts; Preparation steps S1. Raw material drying: Polyester fiber matrix is ​​dried in a constant temperature forced-air drying oven at 85℃ for 3.5 hours, and the moisture content is measured to be 0.4%. S2. Preparation of premix: The composite foaming agent, high-efficiency flame retardant and high-temperature resistant modifier are mixed in a mass ratio of 3:5:2. The mixture is mixed in a high-speed mixer at a speed of 280 r / min for 22 minutes. 0.6 parts of dispersant stearamide are added. The particle size is monitored to be 60-100 μm. The mixture is then activated by ultraviolet light (power 35W, time 11 minutes). S3. Mixing and granulation: Twin-screw mixing and granulating mill, zone 1 130℃, zone 2 145℃, zone 3 150℃, screw speed 450r / min, granulation particle size 2-3mm, melt flow rate 12g / 10min; S4. Foaming molding: Preheat the mold to 120℃ for 14 minutes, press the mold at 165℃ and 8MPa, hold the pressure for 22 minutes, foaming ratio of 4.5 times, shrinkage rate of 4.0%, and then cool down to 120℃ and demold naturally. S5. Post-processing optimization: Grinding wheel speed 1800r / min, high temperature aging (125℃, humidity 30%, time 32 hours), oxygen index test 33%, high temperature resistance test (200℃ for 2 hours, tensile strength retention rate 86%, mass loss rate 3.8%). Example 3 (Environmentally friendly, flame-retardant, lightweight type for automotive interiors) Raw material formula (based on 100 parts by total mass) Polyester fiber matrix: polyethylene terephthalate (40 parts) + polybutylene terephthalate (30 parts), total 70 parts; Composite foaming agent: azodicarbonamide (5 parts) + sodium bicarbonate (2 parts), mass ratio 5:2 (within the range of 4:1 to 3:1), total 7 parts; High-efficiency flame retardant: ammonium polyphosphate (5 parts) + pentaerythritol (2 parts) + melamine (3 parts), mass ratio 5:2:3, total 10 parts; High-temperature resistant modifier: Nano aluminum nitride (2 parts, particle size 60-90nm) + hollow glass microspheres (2 parts, particle size 120-160μm), total 4 parts; Crosslinking agent: dicumyl peroxide (3 parts); Functional additives: hindered phenol 1010 (1.5 parts) + phosphite 168 (1 part) + zinc stearate (1 part) + talc (0.5 parts), antioxidant, lubricant and nucleating agent in a mass ratio of 3:2:1, totaling 4 parts; Preparation steps S1. Raw material drying: Polyester fiber matrix is ​​dried in a constant temperature forced-air drying oven at 95℃ for 2.5 hours, and the moisture content is measured to be 0.2%. S2. Preparation of premix: The composite foaming agent, high-efficiency flame retardant and high-temperature resistant modifier are mixed in a mass ratio of 3:5:2. The mixture is mixed in a high-speed mixer at a speed of 320 r / min for 18 minutes. 0.7 parts of dispersant stearamide are added. The particle size is monitored as 70-130 μm. The mixture is then activated by ultraviolet light (power 45W, time 9 minutes). S3. Mixing and granulation: Twin-screw mixing and granulating mill, zone 1 140℃, zone 2 155℃, zone 3 160℃, screw speed 550r / min, granulation particle size 3-5mm, melt flow rate 18g / 10min; S4. Foaming molding: Preheat the mold to 140℃ for 10 minutes, mold temperature to 175℃, pressure to 12MPa, hold pressure for 18 minutes, foaming ratio to 3.5 times, shrinkage rate to 3.2%, and then cool down to 120℃ and demold naturally. S5. Post-processing optimization: Grinding wheel speed 2200r / min, high temperature aging (135℃, humidity 40%, time 28 hours), oxygen index test 35%, high temperature resistance test (200℃ for 2 hours, tensile strength retention rate 90%, mass loss rate 2.8%). Comparative example (traditional polyester fiber foam material) Raw material formula (based on 100 parts by total mass) Matrix material: Monoethylene terephthalate (85 parts); Foaming agent: Monoazodicarbonamide (8 parts); Flame retardant: Ammonium polyphosphate (6 parts); High-temperature modifier: None; Crosslinking agent: None; Functional additive: Zinc monostearate (1 part); Preparation steps Raw material pretreatment: No drying treatment, just simple mixing of matrix with foaming agent, flame retardant and additives, mixing speed 200 r / min for 15 minutes, no activation and particle size monitoring; Mixed granulation: single-stage mixing temperature 150℃, screw speed 300r / min, no melt flow rate monitoring, granulation particle size is uneven (1-6mm). Foaming molding: No mold preheating, molding temperature 170℃, pressure 6MPa, holding pressure for 20 minutes, no online monitoring or gradient cooling, direct natural cooling and demolding; Post-processing: Simple surface cleaning only, no high-temperature aging treatment, only basic flame retardant performance testing; Comparative analysis Compared with the comparative examples, the three embodiments of the present invention show significant advantages in high temperature resistance (tensile strength retention rate increased by 65%-80% and mass loss rate decreased by 55%-65% after 2 hours of heat treatment at 200℃), flame retardancy (oxygen index increased by 43%-52%), mechanical properties (tensile strength increased by 125%-150% and compressive strength increased by 100%-130%), performance stability (oxygen index change rate decreased by 70%-78% after 1000 hours of artificial accelerated aging), and processing adaptability (stable foaming ratio and particle size uniformity increased by more than 60%). They also achieve the integration of functions such as high temperature resistance, flame retardancy, lightweight, and environmental protection, are suitable for multiple application scenarios, have strong controllability in the preparation process, and are more in line with the needs of industrial production.

[0020] The table below shows the material properties for different groups. Group Oxygen index [%] Tensile strength retention rate after heat treatment at 200℃ for 2 hours [%) Mass loss rate after heat preservation at 200℃ for 2 hours [%) Tensile strength [MPa] Compressive strength [MPa] Change rate of oxygen index after 1000 hours of accelerated artificial aging [%) Foaming ratio Water absorption rate [%) Density [kg / m³] Example 1 34 88 3.2 1.8 0.8 4 4 2.1 260 Example 2 33 86 3.8 1.5 0.6 4.5 4.5 1.9 230 Example 3 35 90 2.8 2.0 0.9 3.5 3.5 2.0 270 Comparative Example 23 53 7.1 0.8 0.4 2.2 2.2 7.8 350 In summary, the advantages of this invention are as follows: This invention uses a combination of nano-aluminum nitride and hollow glass microspheres as high-temperature modifiers, combined with the structural advantages of polyester fiber composite matrix, to enable the material to work stably for a long time in an environment of 120-140℃. After being kept at 200℃ for 2 hours, the tensile strength retention rate is ≥85% and the mass loss rate is ≤5%, which effectively solves the pain points of traditional polyester fiber foam materials being easy to soften and degrade at high temperatures, and broadens its application range in high-temperature scenarios. The material employs an intumescent flame retardant composed of ammonium polyphosphate, pentaerythritol, and melamine, combined with a composite foaming system of azodicarbonamide and sodium bicarbonate, resulting in an oxygen index ≥32%, achieving a flame-retardant rating that meets the requirements of GB / T2406.2—2009 standard. Furthermore, it releases no toxic or harmful gases during combustion, overcoming the shortcomings of traditional halogenated flame retardants in terms of poor environmental performance and improving safety in use. By optimizing the proportions of each component (e.g., a composite foaming agent mass ratio of 4:1 to 3:1 and a functional additive mass ratio of 3:2:1), and introducing pretreatment steps such as raw material moisture content detection, flame retardant activation treatment, and particle size analysis monitoring, the dispersibility and compatibility of the components were effectively improved, avoiding the problem of decreased mechanical properties caused by a single modifier. At the same time, the design of segmented temperature control, online parameter monitoring, and gradient cooling in the preparation process ensures that the foaming ratio of the product is stable at 3 to 5 times, the density is uniform (200 to 300 kg / m³), and the performance fluctuations between batches are small. The preparation process of this invention consists of four core steps: raw material pretreatment, mixing and stirring, foaming and molding, and post-treatment. The parameters for each step are clearly defined (such as drying temperature 80-100℃ and molding pressure 8-12MPa). A real-time monitoring and feedback adjustment mechanism has been added to achieve automated control. At the same time, the process does not require special and expensive equipment, and waste materials can be recycled and mixed for reuse (the proportion does not exceed 10%), which reduces production costs and improves resource utilization. The material of this invention has multiple advantages such as being lightweight, high temperature resistant, flame retardant, sound-insulating, and mechanically stable. It can be applied to multiple fields such as building exterior wall insulation, electronic and electrical appliance packaging, automotive interiors, and rail transit sound insulation materials. It is especially suitable for special environments with high temperature and high risk, and has strong market competitiveness.

[0021] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A high temperature resistant, flame retardant polyester fiber foam material, characterized by, The foaming material comprises: 60-80 parts of polyester fiber matrix, 5-12 parts of composite foaming agent, 8-15 parts of high-efficiency flame retardant, 3-8 parts of high-temperature resistant modifier, 1-4 parts of crosslinking agent and 2-6 parts of functional additives.

2. The high temperature resistant flame retardant polyester fiber foam material according to claim 1, characterized in that: The composite foaming agent is a complex system of azodicarbonamide and sodium bicarbonate with a mass ratio of 4:1-3:1, the polyester fiber matrix is a complex matrix of polyethylene terephthalate and polybutylene terephthalate, and the high-temperature resistant modifier is a complex system of nano-aluminum nitride and hollow glass microbeads.

3. The high temperature resistant flame retardant polyester fiber foam material according to claim 1, characterized in that: The high-efficiency flame retardant is an intumescent flame retardant composed of ammonium polyphosphate, pentaerythritol and melamine with a mass ratio of 5:2:3, the crosslinking agent is dicumyl peroxide, and the functional additives include antioxidants, lubricants and nucleating agents with a mass ratio of 3:2:1, the antioxidant is a complex system of hindered phenol 1010 and phosphite 168, the lubricant is zinc stearate, and the nucleating agent is talc.

4. A method for preparing a high-temperature resistant, flame-retardant polyester fiber foam material, characterized in that, It comprises: S1, raw material pretreatment: the polyester fiber matrix is placed in a forced air drying oven, the temperature is controlled at 80-100°C, and the treatment time is 2-4 hours to remove the internal moisture of the material, and the composite foaming agent, high-efficiency flame retardant and high-temperature resistant modifier are mixed in a high-speed mixer at a mass ratio of 3:5:2, the rotating speed is 250-350 rpm, and the mixing time is 15-25 minutes to prepare the flame-retardant foaming premix; S2, mixing and stirring: the pretreated polyester fiber matrix, flame-retardant foaming premix, crosslinking agent and functional additives are added into a double-screw mixer, the mixing temperature is controlled in three stages as 130-140°C in the first zone, 145-155°C in the second zone and 150-160°C in the third zone, the screw rotating speed is 400-600 rpm, and the mixture is discharged after mixing to prepare the mixed material; S3, foaming and molding: the mixed material is added into a mold pressing foaming machine, the mold pressing temperature is 160-180°C, the mold pressing pressure is 8-12 MPa, the pressure holding foaming time is 15-25 minutes, the foaming ratio is controlled at 3-5 times, and the preliminary foaming and molding material is obtained; S4, post-treatment: the preliminary foaming and molding material is naturally cooled to room temperature after demolding, the surface is trimmed to remove burrs, then high-temperature aging treatment is carried out at a temperature of 120-140°C for 24-36 hours, finally the flame-retardant performance is detected, and the high-temperature resistant flame-retardant polyester fiber foaming material finished product is obtained after passing the detection.

5. The method for preparing a high-temperature resistant flame-retardant polyester fiber foam material according to claim 4, characterized in that, The S1 specifically comprises: After drying, the moisture content of the polyester fiber matrix is detected to ensure that the moisture content is less than or equal to 0.5%; Then, the flame-retardant foaming premix is placed in an ultraviolet irradiation device for activation treatment, the irradiation power is 30-50 W, and the irradiation time is 8-12 minutes to improve the dispersibility of the flame retardant; During the preparation of the flame-retardant foaming premix, 0.5-1.0 parts of dispersant stearic acid amide is added, and a particle size analysis monitoring link is added, the particle size distribution of the premix is detected in real time by a laser particle size analyzer, and the particle size is controlled at 50-150 μm.

6. The method for preparing a high-temperature resistant flame-retardant polyester fiber foam material according to claim 4, characterized in that, The S2 specifically comprises: Before the operation of the double-screw mixer, the cylinder is cleaned by high-pressure nitrogen blowing to remove residual impurities, and then is coated with high-temperature resistant lubricating grease. During the mixing process, a melt flow rate real-time monitoring link is added, which is detected every 5 minutes by a melt flow rate instrument to control the melt flow rate at 10-20 g / 10 min, and when it deviates from the range, the screw speed and mixing temperature are adjusted. After the mixed material is discharged, an appearance detection link is introduced to remove the material containing agglomerates and impurities, and the qualified material is sealed and packaged and stored in a dry environment.

7. The method for preparing a high-temperature resistant flame-retardant polyester fiber foam material according to claim 4, characterized in that, The S3 specifically includes: Before molding, the mold is preheated at a temperature of 120-140°C for 10-15 minutes to reduce temperature loss and temperature difference stress during molding; During the molding and foaming process, the online monitoring system detects the pressure and temperature, and adds a real-time monitoring function of the foaming ratio. The foaming volume is dynamically detected by the volume measurement method, and when the foaming ratio deviates from the set range ±0.3 times, the molding temperature and pressure holding time are automatically adjusted. After foaming is completed, the gradient cooling method is used for cooling, which is first reduced to 120°C at a rate of 5°C / min, and then naturally cooled to 80°C before demolding.

8. The preparation method of the high-temperature-resistant and flame-retardant polyester fiber foaming material according to claim 7, characterized in that: In the online monitoring system, the data of the pressure sensor, the temperature sensor and the foaming ratio detection device are transmitted to the central control system in real time. The system has a built-in parameter comparison and early warning module, which compares the real-time data with the standard parameters. When the deviation exceeds the set threshold, an audible and visual alarm is immediately issued and the process parameters are automatically adjusted. At the same time, the system automatically records the process parameters, detection data and product number of each foaming molding to form a complete production quality traceability database. When the foaming ratio exceeds the standard for two consecutive times, the system automatically stops and prompts to check the activity of the foaming agent and the sealing performance of the mold.

9. The preparation method of the high-temperature-resistant and flame-retardant polyester fiber foaming material according to claim 4, characterized in that: In the S4, a grinding wheel polisher is used for surface finishing at a speed of 1800-2200 revolutions per minute. An efficient dust collection device is provided during polishing to avoid dust pollution and fiber scattering. During high-temperature aging treatment, a constant-temperature air oven is used to control the relative humidity at 30%-40%. The appearance integrity of the material is detected every 12 hours during the aging process. The flame-retardant performance is detected by the oxygen index method according to the GB / T2406.2-2009 standard, and the oxygen index is ≥32% for qualified products.

10. The preparation method of the high-temperature-resistant and flame-retardant polyester fiber foaming material according to claim 4, characterized in that: In the S4, a high-temperature aging treatment step is added after high-temperature aging. The sample is placed in a 200°C constant-temperature oven for 2 hours, and then the tensile strength retention rate is detected to be ≥85% and the mass loss rate is ≤5%; If the detection is not qualified, the sample is re-processed for high-temperature aging treatment, and the aging time is extended by 8-12 hours. The sample is detected again, and if it is still not qualified, it is determined as waste and recycled for crushing and then used as raw material for blending, with a blending ratio of not more than 10%.

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