Drip-proof flame-retardant film and method for manufacturing the same

Abstract

The application discloses a kind of drip-proof flame-retardant films and its manufacturing method, belong to flame-retardant material technical field.Mainly include:Including flame-retardant polyester matrix, the flame-retardant polyester matrix is made by conventional polyester chip and phosphorus flame-retardant masterbatch HY-F4830 according to mass ratio 85:15 co-modification;In the single side or both sides of the flame-retardant polyester matrix Embeddedly combined with the non-combustible fiber preprocessed by coupling agent, the non-combustible fiber length is greater than or equal to 3mm, diameter is 0.1-10µm, and the addition amount is 1-100cm / cm 2 ;The drip-proof flame-retardant film can be processed and formed by unidirectional stretching or biaxial stretching;Through the synergistic effect of the casting preparation process of on-line embedding non-combustible fiber in melt state and the surface pretreatment of coupling agent, the industry pain points of easy clogging filter and invalidation of drip-proof effect in traditional blending method are solved, and the production stability and functional reliability of the drip-proof flame-retardant film are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of flame retardant materials technology, and in particular to an anti-drip flame retardant film and its manufacturing method. Background Technology

[0002] Flame-retardant film is a specially modified polymer film material. While maintaining the physical and mechanical properties of conventional films, it can significantly delay or inhibit the spread of flames by adding flame retardants or composite non-combustible materials, and it can quickly self-extinguish after leaving the fire source. Its main function is to effectively reduce the burning rate of materials in the event of a fire, reduce heat release and smoke generation, thereby buying valuable time for personnel evacuation and fire fighting, while preventing flames from spreading rapidly through the film material, thus improving the safety level in fields such as electronic packaging, building interiors, transportation vehicles and flexible displays.

[0003] The prior art patent document with authorization announcement number CN114351268B discloses "a method for preparing flame-retardant and anti-drip polyester-nylon composite fiber", which includes the following steps: S1, mixing polyester chips, silicone resin, hydroxyphenoxyphosphonic acid and antimony trioxide in a certain ratio and adding them to a screw extruder for melt extrusion to obtain polyester melt; S2, mixing nylon chips, tetramethylolpropionic acid and 4-hydroxymethylphosphonic acid in a certain ratio and adding them to a screw extruder for melt extrusion to obtain nylon melt; S3, adjusting the size of the spinneret holes on the spinneret in advance through the adjusting cylinder; S4, conveying the polyester melt and nylon melt to the spinning box for mixing, and then extruding them through the spinneret holes on the spinneret, and cooling to obtain the desired thickness of flame-retardant and anti-drip polyester-nylon composite fiber product.

[0004] The patent document with authorization announcement number CN116041756B discloses "a method for preparing a high-strength flame-retardant cellulose membrane", the steps of which are as follows: (1) a sodium lignosulfonate aqueous solution with a volume ratio of 1:1 to 1.5 is mixed with a polyamide epichlorohydrin crosslinking agent aqueous solution to form a mixed solution A; (2) a cellulose aqueous dispersion and a polyphosphate ammonium aqueous solution with a polymerization degree of <20 are added to the mixed solution A in step (1) and stirred thoroughly to obtain a mixed solution B; (3) the mixed solution B obtained in step (2) is filtered to form a membrane, heated and dried to obtain a high-strength flame-retardant cellulose membrane.

[0005] While existing technologies can achieve flame retardancy and anti-dripping properties or improve the mechanical and flame retardant properties of flame-retardant films, and can flexibly adjust fiber thickness to adapt to different production needs, and employ green processes without organic solvents, the resulting cellulose films exhibit excellent flame retardancy and mechanical strength, with uniform component dispersion, achieving a synergistic improvement in mechanical and flame retardant properties; however, existing technologies only possess flame retardancy and lack anti-dripping functionality. Molten drips generated during combustion can easily trigger secondary combustion, posing significant safety hazards. Furthermore, there is a fundamental contradiction between the anti-dripping properties of polyester materials and their film-forming processability, making it difficult to achieve both simultaneously. The traditional method of blending non-combustible fibers into polyester melt can clog filtration devices, leading to production interruptions, and the anti-dripping effect is significantly reduced after a large amount of fiber is filtered out, making it impossible to industrially produce flame-retardant polyester films that combine stable processability and excellent anti-dripping performance. Summary of the Invention

[0006] Purpose of the invention: The purpose of this invention is to provide an anti-drip flame-retardant film and its manufacturing method to solve the problems mentioned in the background art.

[0007] Technical Solution: To solve the above-mentioned technical problems, according to one aspect of the present invention, more specifically, a drip-proof flame-retardant film, comprising: a flame-retardant polyester matrix, wherein the flame-retardant polyester matrix is ​​prepared by co-mixing and modifying conventional polyester chips with phosphorus-based flame-retardant masterbatch HY-F4830 at a mass ratio of 85:15; and non-combustible fibers pretreated with a coupling agent are embedded and bonded to one or both sides of the flame-retardant polyester matrix, wherein the non-combustible fibers have a length ≥3mm, a diameter of 0.1-10µm, and an addition amount of 1-100cm / cm. 2 The anti-drip flame-retardant film can be formed by unidirectional or bidirectional stretching.

[0008] Preferably, the non-combustible fiber is selected from one or more of glass fiber, quartz fiber, silicon carbide fiber, silicon nitride fiber, aluminum-based fiber, and fly ash fiber; the non-combustible fiber is one or a combination of straight, curved, branched, or non-combustible fiber mesh structure.

[0009] Preferably, the flame-retardant polyester matrix is ​​a single-layer or multi-layer structure, and the surface layer of the multi-layer flame-retardant polyester matrix is ​​coated with 800-2000 ppm of silica slip agent.

[0010] According to another aspect of the present invention, a method for manufacturing an anti-drip flame-retardant film is provided, comprising the following steps:

[0011] S1. Mix conventional polyester chips with phosphorus-based flame retardant masterbatch HY-F4830 in a certain proportion and then dry them to obtain a qualified mixed raw material.

[0012] S2. The mixed raw materials are fed into an extruder for plasticizing and melting, and then extruded to obtain flame-retardant polyester melt;

[0013] S3. Flame-retardant polyester melt flows out from the slit of the die head, and non-combustible fibers are applied before the melt cools and solidifies. It is then rapidly cooled and shaped by a cooling roller to obtain a basic anti-drip flame-retardant film.

[0014] S4. Modify the basic anti-drip flame retardant film by uniaxial or biaxial stretching according to requirements.

[0015] S5. The stretched membrane is then subjected to edge trimming, dust removal, static electricity elimination, and corona treatment in sequence, and finally wound up to obtain the finished anti-drip flame-retardant membrane.

[0016] Preferably, in step S1, conventional polyester chips and phosphorus-based flame retardant masterbatch HY-F4830 are uniformly mixed at a mass ratio of 85:15, and the moisture content of the material after drying is controlled to be less than 50 ppm.

[0017] Preferably, in step S2, the extrusion temperature for plasticizing and melting is 270-290°C, and 1-3 extruders can be configured to produce single-layer or multi-layer films.

[0018] Preferably, in step S3, after the flame-retardant polyester melt flows out of the die slit but before it cools and solidifies, non-flammable fibers pretreated with a coupling agent are uniformly applied to one or both sides of the melt film, followed by rapid cooling and molding by a cooling roller; the non-flammable fibers have a length ≥3mm, a diameter of 0.1-10µm, and are added at a rate of 1-100cm / cm. 2 It is one or a combination of straight, curved, branched, or network structures.

[0019] Preferably, in step S4, the stretching is divided into longitudinal stretching and transverse stretching. The longitudinal stretching temperature is 80-125℃ and the longitudinal stretching ratio is 2.6-3.8. The transverse stretching temperature is 100-150℃ and the transverse stretching ratio is 3.0-4.0. Unidirectional stretching or bidirectional stretching can be selected according to the requirements.

[0020] Beneficial Effects: By designing a synergistic process of online embedding of non-combustible fibers in a molten state and surface pretreatment with coupling agents, this invention solves the industry pain points of traditional blending methods, such as easy clogging of filters and failure of anti-drip effects. It significantly improves the production stability and functional reliability of anti-drip flame-retardant films. By precisely limiting the synergistic parameters of the length, diameter, and amount of non-combustible fibers, it achieves completely melt-drip-free combustion, eliminating the risk of secondary combustion at its source. The online application process using casting does not alter the processing properties of the polyester matrix and is compatible with conventional unidirectional / bidirectional stretching processes, preserving the excellent mechanical properties of the film. Coupling agent pretreatment strengthens the fiber-matrix interface bonding, preventing fiber shedding and product defects. Furthermore, it enables industrial-scale mass production based on existing equipment modifications, significantly reducing production costs. This invention not only solves the contradiction between anti-drip properties and processability, and the poor production continuity of traditional flame-retardant films, but also provides a safe and economical technical path for the large-scale preparation of high-performance flame-retardant protective films. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0022] Figure 2 This is a schematic diagram of the molding process of the present invention. Detailed Implementation

[0023] To make the technical solution of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1

[0025] A drip-proof flame-retardant film and its manufacturing method are described below:

[0026] S1. Raw material blending and drying: Conventional polyester chips and phosphorus-based flame retardant masterbatch HY-F4830 are uniformly mixed at a mass ratio of 85:15 and placed in a drying equipment to dry until the moisture content of the material is 45ppm, thus obtaining a qualified dried mixed raw material.

[0027] S2, Melt Plasticizing Extrusion: The mixed raw materials are fed into a single main extruder, and the extrusion temperature is controlled at 270°C. After plasticizing and melting, flame-retardant polyester melt is obtained by extrusion. For multi-layer structures, an additional extruder can be added. In this embodiment, it is a single-layer film, and no slip agent is added to the surface.

[0028] S3, molten fiber application and cooling molding (e.g.) Figure 2 (As shown): After the flame-retardant polyester melt flows out of the die slit, before it cools and solidifies, glass fibers pretreated with a silane coupling agent are uniformly applied to one side of the melt film; the glass fibers have a diameter of 0.5µm, a length of 3mm, and an addition amount of 10cm / cm. 2 The fibers are linear; they are then rapidly cooled and shaped by cooling rollers to obtain a basic anti-drip flame-retardant film.

[0029] S4. Biaxial stretching modification: The base film is fed into a longitudinal stretching machine and heated to 80°C for longitudinal stretching with a longitudinal stretching ratio of 2.6; then it is fed into a transverse stretching machine and heated to 100°C for transverse stretching with a transverse stretching ratio of 3.0.

[0030] S5. Post-processing and winding: The stretched film is successively subjected to edge trimming, dust removal, static electricity elimination, and corona treatment, and finally wound up to obtain the finished anti-drip flame-retardant film.

[0031] Example 2

[0032] A drip-proof flame-retardant film and its manufacturing method are described below:

[0033] S1. Raw material blending and drying: Conventional polyester chips and phosphorus-based flame retardant masterbatch HY-F4830 are uniformly mixed at a mass ratio of 85:15 and dried until the moisture content of the material is 40ppm to obtain a qualified mixed raw material.

[0034] S2. Melt Plasticizing Extrusion: Two extruders are used to produce double-layer structured films. The main extruder has an extrusion temperature of 280℃. 1000ppm of silica slip agent is added to the surface melt. After plasticizing and melting, double-layer flame-retardant polyester melt is obtained by extrusion.

[0035] S3. Application and Cooling of Melt-State Fibers: After the flame-retardant polyester melt flows out of the die slit, before it cools and solidifies, quartz fibers pretreated with a silane coupling agent are uniformly applied to one side of the melt film; the quartz fibers have a diameter of 2µm, a length of 8cm, and an addition amount of 20cm / cm. 2 The fiber morphology is a type with side branches; it is then rapidly cooled and shaped by cooling rollers to obtain a basic anti-drip flame-retardant film.

[0036] S4. Biaxial stretching modification: The base membrane is longitudinally stretched at 95℃ with a stretch ratio of 3.2; then transversely stretched at 125℃ with a stretch ratio of 3.5.

[0037] S5. Post-processing and winding: The stretched film is successively subjected to edge trimming, dust removal, static electricity elimination, and corona treatment, and finally wound up to obtain the finished anti-drip flame-retardant film.

[0038] Example 3

[0039] A drip-proof flame-retardant film and its manufacturing method are described below:

[0040] S1. Raw material blending and drying: Conventional polyester chips and phosphorus-based flame retardant masterbatch HY-F4830 are uniformly mixed at a mass ratio of 85:15 and dried until the moisture content of the material is 35ppm to obtain a qualified mixed raw material.

[0041] S2. Melt Plasticizing Extrusion: Three extruders are used to produce a three-layer structure film. The main extruder has an extrusion temperature of 290℃. 2000ppm of silica slip agent is added to the surface melt. After plasticizing and melting, the three-layer flame-retardant polyester melt is obtained by extrusion.

[0042] S3. Application and Cooling of Melt-State Fibers: After the flame-retardant polyester melt flows out of the die slit, before it cools and solidifies, silicon carbide fibers pretreated with a silane coupling agent are uniformly applied to both sides of the melt film; the silicon carbide fibers have a diameter of 5µm, a length of 15cm, and an addition amount of 50cm / cm. 2 The fiber has a mesh structure; it is then rapidly cooled and shaped by cooling rollers to obtain a basic anti-drip flame-retardant film.

[0043] S4. Biaxial stretching modification: The base membrane is longitudinally stretched at 125℃ with a stretch ratio of 3.8; then transversely stretched at 150℃ with a stretch ratio of 4.0.

[0044] S5. Post-processing and winding: The stretched film is successively subjected to edge trimming, dust removal, static electricity elimination, and corona treatment, and finally wound up to obtain the finished anti-drip flame-retardant film.

[0045] Experimental Example 1

[0046] Experimental objective:

[0047] The effects of non-combustible fiber length and addition amount on the anti-dripping performance of flame-retardant film were verified, and the key parameter thresholds for achieving non-melting dripping were determined.

[0048] Experimental materials and basic sample parameters:

[0049] Base membrane material: 50µm thick flame-retardant polyester membrane, the substrate is prepared by blending conventional polyester chips with phosphorus-based flame-retardant masterbatch HY-F4830 at a mass ratio of 85:15.

[0050] Adding fibers: Apply straight glass fibers with a diameter of 2µm (pretreated with coupling agent) to one side.

[0051] Preparation process: The casting method was used for molding, and no stretching treatment was performed. The remaining preparation steps were the same as in Example 1.

[0052] Sample preparation:

[0053] With fixed fiber diameter, morphology, and application surface, and only adjusting fiber length and dosage per unit area, 21 evaluation samples were prepared. The grouping parameters are as follows:

[0054] Fiber lengths: 0cm, 1cm, 2cm, 8cm, 15cm, 20cm.

[0055] Fiber addition: 2cm / cm 2 5cm / cm 2 10cm / cm 2 20cm / cm 2 .

[0056] Test sample pretreatment:

[0057] Environmental conditioning: Place in an environment of 23±2℃ and 50±10%RH for at least 48 hours.

[0058] Heat aging treatment: Aging at 70±2℃ for 168±2h, followed by cooling in a desiccator to room temperature for at least 4h.

[0059] Test spline cutting:

[0060] All samples were cut to standard dimensions: length 125±5mm, width 13±0.5mm.

[0061] Vertical burning test procedure:

[0062] Clamping: Clamp the upper 6mm portion of the sample to keep it suspended vertically.

[0063] Flame adjustment: Adjust the Bunsen lamp to stabilize the flame height at 20±1mm.

[0064] Ignition test: The Bunsen lamp is placed at the center below the sample, with the distance between the lamp opening and the bottom of the sample being 10±1mm, and ignition time is 10±0.5s.

[0065] Lamp removal observation: After ignition, move the Bunsen lamp away at a speed of 300 mm / s by at least 150 mm, and simultaneously record the molten dripping of the sample during combustion.

[0066] The record table is shown below:

[0067]

[0068] Experimental conclusion:

[0069] Fiber length < 8cm or addition amount < 10cm / cm 2 When the flame-retardant film burns, it melts and drips, rendering the anti-dripping effect ineffective.

[0070] When fiber length is ≥8cm and addition amount is ≥10cm / cm 2 When burning, the flame-retardant film does not melt or drip, and its anti-drip performance meets the standards.

[0071] The anti-drip effect depends on the synergistic effect of fiber length and amount added. Adjusting a single parameter cannot achieve drip-free operation, thus verifying the necessity of parameter limitation in this invention.

[0072] Comparative Example 1

[0073] The difference between Comparative Example 1 and Examples 1-3 is as follows: Comparative Example 1 (refer to the prior art document CN114351268B in the background section) specifically is:

[0074] Mix 80 parts polyester chips, 15 parts silicone resin, 30 parts hydroxyphenoxyphosphonic acid and 5 parts antimony trioxide evenly, and then add them to a screw extruder for melt extrusion to obtain polyester melt.

[0075] Mix 70 parts of nylon chips, 30 parts of tetrahydroxymethyl urea and 10 parts of 4-hydroxymethyl phosphine sulfate evenly, and then add them to a screw extruder for melt extrusion to obtain nylon melt.

[0076] The size of the spinneret's nozzles can be adjusted by adjusting the tube.

[0077] Polyester melt and nylon melt are transported into the spinning box for mixing, and then sprayed out through the spinneret holes and cooled to obtain flame-retardant and anti-drip polyester-nylon composite fiber.

[0078] Comparative Example 2

[0079] The difference between Comparative Example 2 and Examples 1-3 is as follows: Comparative Example 2 (refer to the prior art document CN116041756B in the background section) specifically is:

[0080] A 0.8% sodium lignosulfonate aqueous solution and a 1.3% polyamide epichlorohydrin aqueous solution were mixed at a volume ratio of 1:1 to form mixed solution A.

[0081] Add 10% by mass of bacterial cellulose aqueous dispersion and 1% by mass of ammonium oligophosphate aqueous solution with a degree of polymerization <20 to mixed solution A. The volume ratio of cellulose aqueous dispersion, ammonium oligophosphate aqueous solution and mixed solution A is 50:15:7. Stir thoroughly to obtain mixed solution B.

[0082] The mixed solution B was filtered into a membrane and dried at 150°C for 60 minutes to obtain a high-strength flame-retardant cellulose membrane.

[0083] Comparative Example 3

[0084] The difference between Comparative Example 3 and Examples 1-3 is as follows: Comparative Example 3 (refer to prior art document CN119463308A) is specifically:

[0085] Carbon dots were prepared by hydrothermal reaction at 200℃ for 8 hours using ginkgo leaves and ethylenediamine as raw materials, and the carbon dot solution was obtained by centrifugation and dialysis purification.

[0086] Under the action of EDC / NHS initiator, carbon dots are reacted with nanocellulose suspension, and purified by dialysis to obtain carbon dot modified nanocellulose suspension.

[0087] The titanate nanofibers prepared by hydrothermal reaction were added to the above suspension and stirred until uniformly dispersed.

[0088] Epichlorohydrin crosslinking agent was added, and the mixture was quickly stirred and dispersed before being cast into a petri dish. The mixture was then cured in a vacuum drying oven at 55°C for 10 hours to obtain a flame-retardant cellulose composite film.

[0089] To illustrate the use of the flame-retardant film described in this invention, flame-retardant films prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to tests. The test methods are as follows:

[0090] Vertical combustion anti-drip test: According to the standard method of this invention, the sample was cut to 125±5mm×13±0.5mm, pretreated in an environment of 23±2℃ and 50±10%RH for 48h and then heat-aged at 70±2℃ for 168h. The sample was then vertically clamped, the flame height was adjusted to 20±1mm, the flame was removed after 10s of ignition, and the combustion melting and dripping were recorded.

[0091] Tensile mechanical property test: According to GB / T 1040.3-2006, the sample was made into a standard strip of 150mm×15mm and stretched at a rate of 200mm / min to test the tensile breaking strength and characterize the mechanical load-bearing performance of the membrane.

[0092] Limiting Oxygen Index (LOI) Test: Refer to GB / T 2406.2-2009. Cut the sample into 100mm×10mm strips, place them vertically in the combustion chamber, adjust the nitrogen-oxygen mixture flow, determine the minimum oxygen concentration required to maintain combustion, and evaluate the flame retardancy rating.

[0093] Extrusion filtration differential pressure test: Using a filtration device of equal precision, continuous production for 2 hours was carried out, and the pressure difference before and after the extruder filter screen was recorded to evaluate the degree of clogging effect of the fibers on the filtration system.

[0094] Fiber interface bonding strength test: The 3M 600 tape peeling method was used. After the tape was evenly applied to the film surface, it was quickly peeled off and rated according to GB / T 9286-1998.

[0095] The test results are shown in the table below:

[0096]

[0097] As can be seen from the comparison of the embodiments and comparative examples, the present invention applies non-combustible fibers pretreated with coupling agents online before the melt extrusion die solidifies, eliminating the defects of traditional melt-blended fiber processes. It bypasses the filtration stage in the processing path, effectively solving the industry problems of fiber clogging of the filter screen and poor production continuity. This process allows the non-combustible fibers to form a strong embedded bond with the polyester matrix, preventing fiber detachment from affecting product quality. Simultaneously, it precisely achieves combustion without melt dripping, eliminating the secondary combustion safety hazard caused by melt dripping. While imparting excellent anti-drip properties to the film, the present invention fully retains the stretching processing characteristics of polyester film, giving the film both excellent mechanical and flame-retardant properties. Its overall performance is far superior to existing technologies. It is compatible with existing casting film equipment and can achieve large-scale mass production without significant modifications, balancing production stability, product reliability, and economy. It provides a new and feasible technical path for the industrial application of high-performance anti-drip flame-retardant films.

[0098] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A drip-proof flame-retardant film, characterized in that, include: The product includes a flame-retardant polyester matrix, which is prepared by co-mixing and modifying conventional polyester chips with phosphorus-based flame-retardant masterbatch HY-F4830 at a mass ratio of 85:

15. Non-flammable fibers pretreated with a coupling agent are embedded on one or both sides of the flame-retardant polyester matrix. These non-flammable fibers have a length ≥3mm, a diameter of 0.1-10µm, and are added at a rate of 1-100cm / cm². 2 The anti-drip flame-retardant film can be formed by unidirectional or bidirectional stretching.

2. The anti-drip flame-retardant film according to claim 1, characterized in that, include: The non-combustible fiber is selected from one or more of glass fiber, quartz fiber, silicon carbide fiber, silicon nitride fiber, aluminum-based fiber, and fly ash fiber; the non-combustible fiber is one or a combination of straight, curved, branched, or non-combustible fiber mesh structure.

3. The anti-drip flame-retardant film according to claim 1, characterized in that, include: The flame-retardant polyester matrix is ​​a single-layer or multi-layer structure, and the surface layer of the multi-layer flame-retardant polyester matrix is ​​coated with 800-2000 ppm of silica slip agent.

4. A method for manufacturing an anti-drip flame-retardant film, comprising the anti-drip flame-retardant film as described in claims 1-3, characterized in that, Includes the following steps: S1. Mix conventional polyester chips with phosphorus-based flame retardant masterbatch HY-F4830 in a certain proportion and then dry them to obtain a qualified mixed raw material. S2. The mixed raw materials are fed into an extruder for plasticizing and melting, and then extruded to obtain flame-retardant polyester melt; S3. Flame-retardant polyester melt flows out from the slit of the die head, and non-combustible fibers are applied before the melt cools and solidifies. It is then rapidly cooled and shaped by a cooling roller to obtain a basic anti-drip flame-retardant film. S4. Modify the basic anti-drip flame retardant film by uniaxial or biaxial stretching according to requirements. S5. The stretched membrane is then subjected to edge trimming, dust removal, static electricity elimination, and corona treatment in sequence, and finally wound up to obtain the finished anti-drip flame-retardant membrane.

5. The method for manufacturing an anti-drip flame-retardant film according to claim 4, characterized in that: In S1, conventional polyester chips and phosphorus-based flame retardant masterbatch HY-F4830 are uniformly mixed at a mass ratio of 85:15, and the moisture content of the material after drying is controlled to be less than 50 ppm.

6. The method for manufacturing an anti-drip flame-retardant film according to claim 4, characterized in that: In S2, the extrusion temperature for plasticizing and melting is 270-290℃, and 1-3 extruders can be configured to produce single-layer or multi-layer films.

7. The method for manufacturing an anti-drip flame-retardant film according to claim 4, characterized in that: In step S3, after the flame-retardant polyester melt flows out of the die slit but before it cools and solidifies, non-flammable fibers pretreated with a coupling agent are uniformly applied to one or both sides of the melt film, followed by rapid cooling and molding by a cooling roller; the non-flammable fibers have a length ≥3mm, a diameter of 0.1-10µm, and are added at a rate of 1-100cm / cm. 2 It is one or a combination of straight, curved, branched, or network structures.

8. The method for manufacturing an anti-drip flame-retardant film according to claim 4, characterized in that: In S4, the stretching is divided into longitudinal stretching and transverse stretching. The longitudinal stretching temperature is 80-125℃ and the longitudinal stretching ratio is 2.6-3.

8. The transverse stretching temperature is 100-150℃ and the transverse stretching ratio is 3.0-4.

0. Unidirectional stretching or bidirectional stretching can be selected according to the requirements.

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