Rare earth Ce-O-P core-shell structure coated TPU flame retardant material and preparation method thereof

Abstract

This invention relates to a rare-earth Ce-O-P core-shell structure-coated TPU flame-retardant material and its preparation method, belonging to the field of polymer combustion-supporting materials technology. It aims to address the problems of poor water resistance, easy precipitation of flame retardants, and decreased flame retardant rating and mechanical properties after boiling in water in existing flame-retardant TPUs. The material of this invention is composed of TPU, a rare-earth CeOP core-shell structure halogen-free flame retardant, a compatibilizer and dispersant, mineral oil, and an antioxidant; wherein the halogen-free flame retardant includes a rare-earth cerium phenylphosphonate compound and a phosphorus-nitrogen flame retardant. This invention obtains the rare-earth CeOP core-shell structure flame retardant through stepwise synthesis, and then blends and granulates it with TPU and other materials. After boiling in water at 90-120℃ for 168 hours, the material shows no precipitation, maintains the UL94 V0 rating (0.8mm), retains a tensile strength of >90%, and a breakage elongation of >100%.

Description

Technical Field

[0001] This invention belongs to the field of polymer flame retardant materials technology, and relates to a rare earth Ce-OP core-shell structure TPU-coated flame retardant material and its preparation method. Background Technology

[0002] Thermoplastic polyurethane elastomer (TPU) is a high-performance polymer material. It possesses excellent properties such as high strength, high elasticity, abrasion resistance, oil resistance, and low-temperature resistance. TPU has a wide hardness range, which can be adjusted to meet different needs. In terms of applications, it is widely used in footwear, pipes, films, cables, and other fields. Its excellent resilience makes athletic shoes more comfortable, and its good abrasion resistance extends the service life of pipes. TPU also has the advantages of easy processing and recyclability, meeting the requirements of environmental protection and sustainable development, making it an indispensable high-quality material in modern industry. TPU has a limiting oxygen index (LOI) of approximately 16%, classifying it as a flammable material. When exposed to fire, it burns rapidly and decomposes, producing large amounts of toxic fumes, including toxic gases such as NO, CO, and HCN, accompanied by severe dripping, posing a significant threat to human life and property. Therefore, the development and application of flame-retardant TPU materials have important social significance.

[0003] Currently, additive flame retardants are the most common type used in the market. Inorganic flame retardants, such as aluminum hydroxide and magnesium hydroxide, have advantages such as low price, wide availability, and non-toxicity. They exert their flame-retardant effect by decomposing endothermally during combustion, releasing water vapor, and diluting the concentration of flammable gases and oxygen. However, their addition amount is relatively large, often affecting the mechanical and processing properties of TPU. Organophosphorus flame retardants are another common type of TPU flame retardant, such as phosphate esters and phosphonates. They have the characteristics of high flame-retardant efficiency and good compatibility with TPU. They inhibit flame propagation by acting in both the condensed and gas phases. However, some organophosphorus flame retardants may have certain toxicity and environmental problems. Nitrogen-based flame retardants, such as melamine and its derivatives, are also used in TPU. Their flame-retardant mechanism mainly involves decomposition to produce non-flammable gases, which play a dilution and covering role. Furthermore, when used in conjunction with other flame retardants, they can produce better flame-retardant effects. In addition, some new flame retardants, such as nano flame retardants and intumescent flame retardants, are also showing good application prospects in the field of TPU flame retardancy. With the continuous expansion of TPU applications, such as TPU charging piles for new energy vehicles, charging cables, and special pipelines for high-temperature liquid environments, higher requirements are being placed on TPU materials in terms of water resistance, exudation resistance, and mechanical failure resistance, in addition to high flame retardancy. Currently, the main flame retardant materials for industrial application are phosphorus-based materials such as aluminum diethyl phosphite (ADP) and nitrogen-based melamine cyanurate (MCA) single components. However, there is relatively little research on water resistance and mechanical properties, especially boiling water resistance, which has more stringent requirements and demands higher material performance. In particular, there is almost no research on flame retardant materials that possess high boiling water resistance and mechanical property retention.

[0004] In the prior art, patent application CN201410249423.7 discloses a halogen-free flame-retardant and antistatic TPU material and its preparation method. This TPU flame-retardant and antistatic material is obtained by mixing thermoplastic polyurethane elastomer, flame retardant, antistatic agent, antioxidant, and lubricant. The resulting material has certain flame retardancy and antistatic properties, but its water resistance has not been studied. Patent application CN202411020857.X discloses a highly hydrolysis-resistant halogen-free flame-retardant thermoplastic polyurethane elastomer and its preparation method, mainly composed of a mixture of TPU, halogen-free flame retardant, highly hydrolysis-resistant additives, and antioxidants. The resulting material is hydrolysis-resistant, and its flame retardant performance can reach UL94 V-0. However, the hydrolysis-resistant agent used may precipitate over time, thus reducing its hydrolysis resistance. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a rare-earth Ce-OP core-shell structure-coated TPU flame-retardant material and its preparation method. This material utilizes the unique "core-shell" structure formed by rare-earth cerium (Ce) and organophosphonic acid to surface-modify conventional phosphorus and nitrogen flame retardants, thereby significantly improving the interfacial compatibility, migration resistance, and thermal stability between the flame retardant and the TPU matrix. The resulting material effectively prevents flame retardant precipitation after undergoing harsh boiling conditions, maintaining an extremely high flame retardant rating and excellent mechanical properties, thus solving the key problem of poor resistance to damp heat aging in existing flame-retardant TPUs.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a rare earth Ce-OP core-shell structure coated TPU flame retardant material, comprising the following parts by weight: 50-80 parts of polyether-type TPU, 20-40 parts of rare earth Ce-OP core-shell structure halogen-free flame retardant, 2-5 parts of compatibilizer and dispersant, 10-20 parts of mineral oil, and 0.5-1 parts of antioxidant. The rare earth Ce-OP core-shell structure halogen-free flame retardant comprises a rare earth cerium phenylphosphonate compound and a phosphorus-nitrogen halogen-free flame retardant, wherein the rare earth cerium phenylphosphonate compound is added in a proportion of 0.5-2.0 parts.

[0007] This invention provides a rare earth Ce-OP core-shell structure coated TPU flame retardant material, comprising the following parts by weight: 50-80 parts polyester TPU, 20-40 parts rare earth Ce-OP core-shell structure halogen-free flame retardant, 2-5 parts compatibilizer and dispersant, 10-20 parts mineral oil, and 0.5-1 parts antioxidant. The rare earth Ce-OP core-shell structure halogen-free flame retardant comprises a rare earth cerium phenylphosphonate compound and a phosphorus-nitrogen halogen-free flame retardant, wherein the rare earth cerium phenylphosphonate compound is added in an amount of 0.5-2.0 parts. Preferably, the rare earth cerium phenylphosphonic acid compound is composed of any one of phenylphosphonic acid, diphenylphosphonic acid, (4-aminophenyl)phosphonic acid, and (2-aminophenyl)phosphonic acid, combined with any one of cerium nitrate hexahydrate, cerium chloride hexahydrate, cerium acetate hydrate, cerium acetylacetone hydrate, and cerium acetate hydrate. Preferably, the halogen-free flame retardant is selected from at least one of FR140A, FR140B, FR140N, and FR1400, or at least two of aluminum diethylphosphinate, aluminum hypophosphite, melamine cyanurate, piperazine pyrophosphate, aluminum phosphite, boric acid, rare earth elements, metal hydroxides, and metal oxides, or 90-98% carrier-free flame retardant masterbatch; Preferably, the compatibilizer and dispersant is at least one of the following: trinonyl trimellitate, di(butoxyethoxyethyl) adipic acid, trioctyl trimellitate, terminal polyisobutylene, and copolymer of propylene oxide and ethylene oxide. Preferably, the mineral oil is selected from at least one of aromatic oils, naphthenic oils, and paraffin oils; Preferably, the antioxidant is selected from at least one of antioxidant 168, antioxidant 1010, antioxidant 1076 and antioxidant DLTDP; Furthermore, the preparation method of the rare earth Ce-OP core-shell structure coated TPU flame retardant material includes the following steps: S1: Preparation of rare earth Ce-OP core-shell structured compounds: Phenylophosphonic acid and cerium compound were added to an ethanol-water mixed solvent with a mass ratio of 7:3 at a mass ratio of 1:(1.0-1.5). The mixture was reacted at 80-120℃ for 12-14 hours. After the reaction was completed, the mixture was washed with deionized water, filtered, and dried to obtain Ce-OP core-shell structured cerium phenylphosphonate. S2: Rare earth Ce-OP core-shell structure halogen-free flame retardant: Ce-OP core-shell phenylphosphonate, FR140N, titanate coupling agent, and aluminate coupling agent were added to a high-speed mixer at a mass ratio of 100:(850~950):(3-5):(3-5) and mixed at 80-120℃ and 500-1000 rpm for 10-30 min to obtain a rare earth Ce-OP core-shell halogen-free flame retardant. S3: Preparation of rare earth Ce-OP core-shell structured TPU flame retardant material: After drying polyether-type TPU or polyester-type TPU at 80-90℃ for 4-6 hours, it is mixed with rare earth Ce-OP core-shell structure halogen-free flame retardant, compatibilizer, dispersant, mineral oil and antioxidant obtained in step S2 for 10-30 minutes. Then, the mixture is melt-blended, extruded, cooled and granulated by a twin-screw extruder, and dried to obtain the rare earth Ce-OP core-shell structure coated TPU flame retardant material. Preferably, the process parameters of the twin-screw extruder in step S3 are: screw length-to-diameter ratio L / D = 36:1-40:1, main machine speed 250-400 rpm, and processing temperature from zone one to the die head is 130-170℃, 140-190℃, and 160-200℃ respectively.

[0008] An article made of a flame-retardant material prepared from the aforementioned flame-retardant material, the article being a cable sheath, a charging pile assembly, a fluid-resistant pipeline, or a shoe material.

[0009] The beneficial effects of this invention are as follows: Excellent water / oil resistance: The prepared material can pass the rigorous test of boiling in water at 120℃ for 168 hours (7 days), with no powdering, no stickiness, and no visible exudation of flame retardant on the surface, solving the industry problem of easy migration and exudation of traditional flame retardant TPU in humid and hot environments.

[0010] 100% flame retardant performance maintained after boiling: After the above boiling treatment, the material burns without any molten droplets, the burning layer is firmly bonded to the substrate, the flame retardant rating remains at UL94 V-0 (test thickness can be as low as 0.8mm), and the performance is not degraded.

[0011] Excellent mechanical property retention: After boiling in water for 168 hours, the tensile strength retention rate of the material is >90%, and the elongation at break retention rate is >100% (due to the plasticizing effect of water molecules), which is much higher than that of the comparative material (tensile strength decreased by about 30%), indicating that the structural integrity of the material remains good after boiling in water.

[0012] The process is mature and easy to industrialize: the raw materials used are readily available, and the preparation method is based on conventional polymer blending and modification processes (high-speed mixing, twin-screw extrusion), requiring no special equipment and suitable for large-scale production.

[0013] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0014] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein: Figure 1 This is the condition before boiling; Figure 2 This is the result after boiling. Detailed Implementation

[0015] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0016] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0017] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0018] Example: Polyether-type TPU flame retardant material 1. Preparation of rare earth Ce-OP core-shell structured compounds: Phenylophosphonic acid and cerium nitrate hexahydrate were added to an ethanol-water mixed solvent (ethanol:water = 7:3, mass ratio) at a mass ratio of 1:1.2, and reacted at 100°C for 13 hours. After the reaction was completed, the product was washed three times with deionized water, filtered, and dried in a vacuum drying oven at 80°C for 12 hours to obtain a white powder of Ce-OP core-shell structured cerium phenylphosphonate.

[0019] 2. Preparation of rare earth Ce-OP core-shell structure halogen-free flame retardant: 10g of cerium phenylphosphonate, 900g of FR140N, 4g of titanate coupling agent (NDZ-201), and 4g of aluminate coupling agent (DL-411) prepared above were added to a high-speed mixer and mixed at 100℃ and 800rpm for 20 minutes. The resulting material was a rare earth Ce-OP core-shell structure halogen-free flame retardant (Ce-OP / cerium phenylphosphonate).

[0020] 3. Preparation of rare earth Ce-OP core-shell structure coated TPU flame retardant material: (1) Dry the polyether-type TPU (Lubrizol 58219, hardness 92A) in an 85°C forced-air drying oven for 5 hours.

[0021] (2) According to the formula (parts by weight) shown in Table 1, add the dried TPU, FR140N, rare earth Ce-OP core-shell structure halogen-free flame retardant (Ce-OP / cerium phenylphosphonate) prepared in step 2, compatibilizer and dispersant (trioctyl trimellitate), mineral oil (naphthenic oil), antioxidant (1010 and 168 compounded in 1:1) into the mixer and mix for 20 minutes.

[0022] (3) Melt blending and granulation were carried out using a twin-screw extruder (screw length-to-diameter ratio 38:1). Process parameters: main extruder speed 350 rpm, processing temperatures from zone 1 to the die head are: 150℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 200℃ (die head). The extruded strips were water-cooled, air-dried, and then granulated.

[0023] 4. Test strip preparation method: (1) Dry the TPU flame retardant material sample obtained by extrusion granulation in a forced-air drying oven at a temperature of 80-90℃ for 2-4 hours; (2) Injection molding is performed using an injection molding machine with an injection temperature of 180-210℃, an injection pressure of 40-50MPa, and an injection speed of 40-60mm / s.

[0024] (3) Splines include: tensile, impact and flame retardant.

[0025] 5. Performance Testing Methods (1) Water boiling resistance test: The sample was completely immersed in deionized water at 90℃±2℃ for 168 hours (7 days). After removal, the surface moisture was wiped off, and the sample was placed under standard conditions (23℃, 50%RH) for 24 hours before testing.

[0026] (2) Flame retardant performance: Vertical burning test was conducted according to UL94 standard, and the flammability rating and test thickness were recorded.

[0027] (3) Mechanical properties: tensile strength and elongation at break were tested according to ASTM D638 standard.

[0028] Table 1: Formulation of Polyether-based TPU Flame Retardant Material

[0029] The test results are summarized in Table 2.

[0030] Table 2: Performance Comparison of Polyether-based TPU Flame Retardant Materials

[0031] The results showed that after boiling in water for 168 hours, Examples 1 and 2 of the present invention maintained a flame retardant rating of V-0 (Example 2 even maintained V-0 at a thickness of 0.8 mm), and the tensile strength retention rate was above 93%, with even an improvement in elongation at break. In contrast, Comparative Examples 1 and 2 (using uncoated FR140N) showed a decrease in flame retardant rating after boiling (requiring increased thickness to achieve V-0), and a tensile strength loss of nearly 30%.

[0032] Example: Polyester-type TPU flame retardant material 1. Preparation of rare earth Ce-OP core-shell structured compounds: Phenylophosphonic acid and cerium nitrate hexahydrate were added to an ethanol-water mixed solvent (ethanol:water = 7:3, mass ratio) at a mass ratio of 1:1.2, and reacted at 100°C for 13 hours. After the reaction was completed, the product was washed three times with deionized water, filtered, and dried in a vacuum drying oven at 80°C for 12 hours to obtain a white powder of Ce-OP core-shell structured cerium phenylphosphonate.

[0033] 2. Preparation of rare earth Ce-OP core-shell structure halogen-free flame retardant: 10g of the Ce-OP core-shell structured cerium phenylphosphonate, 900g of FR140N, 4g of titanate coupling agent (NDZ-201), and 4g of aluminate coupling agent (DL-411) prepared above were added to a high-speed mixer and mixed at 100℃ and 800rpm for 20 minutes. The resulting material was a rare earth Ce-OP core-shell structured halogen-free flame retardant (Ce-OP / cerium phenylphosphonate).

[0034] 3. Preparation of rare earth Ce-OP core-shell structure coated TPU flame retardant material: (1) Polyester TPU (Lubrizol 2355-95AEF, hardness 94A) was dried in an 85℃ forced-air drying oven for 5 hours.

[0035] (2) According to the formula (parts by weight) shown in Table 3, add the dried TPU, FR140N, rare earth Ce-OP core-shell structure halogen-free flame retardant (Ce-OP / cerium phenylphosphonate) prepared in step 2, compatibilizer and dispersant (trioctyl trimellitate), mineral oil (naphthenic oil), antioxidant (1010 and 168 compounded in 1:1) into the mixer and mix for 20 minutes.

[0036] (3) Melt blending and granulation were carried out using a twin-screw extruder (screw length-to-diameter ratio 38:1). Process parameters: main extruder speed 350 rpm, processing temperatures from zone 1 to the die head are: 150℃, 170℃, 175℃, 180℃, 185℃, 190℃, 195℃, 200℃ (die head). The extruded strips were water-cooled, air-dried, and then granulated.

[0037] 4. Test strip preparation method: (1) Dry the TPU flame retardant material sample obtained by extrusion granulation in a forced-air drying oven at a temperature of 80-90℃ for 2-4 hours; (2) Injection molding is performed using an injection molding machine with an injection temperature of 180-210℃, an injection pressure of 40-50MPa, and an injection speed of 40-60mm / s.

[0038] (3) Splines include: tensile, impact and flame retardant.

[0039] 5. Performance Testing Methods (1) Water boiling resistance test: The sample was completely immersed in deionized water at 90℃±2℃ for 168 hours (7 days). After removal, the surface moisture was wiped off, and the sample was placed under standard conditions (23℃, 50%RH) for 24 hours before testing.

[0040] (2) Flame retardant performance: Vertical burning test was conducted according to UL94 standard, and the flammability rating and test thickness were recorded.

[0041] (3) Mechanical properties: tensile strength and elongation at break were tested according to ASTM D638 standard.

[0042] Table 3: Formulation Table of Polyester-based TPU Flame Retardant Materials

[0043] The test results are summarized in Table 4.

[0044] Table 4: Performance Comparison of Polyester-Based TPU Flame Retardant Materials

[0045] The above data shows that the rare earth Ce-OP core-shell structure halogen-free flame retardant has a better flame retardant effect on polyester TPU. Only 5 parts are needed to pass the 1.6mm V-0 test, and only 8 parts are needed to pass the 0.8mm V-0 test. After boiling in water at 90℃ for 168 hours, the flame retardant rating remains at 100%, and the tensile strength retention rate exceeds 90%, effectively solving the key problems of easy flame retardant precipitation and mechanical property degradation in polyester TPU under humid and hot environments.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A rare earth Ce-O-P core-shell structure coated TPU flame retardant material, characterized in that: It comprises the following components by weight: 50-80 parts of polyether-type TPU, 20-40 parts of rare earth Ce-OP core-shell structure halogen-free flame retardant, 2-5 parts of compatibilizer and dispersant, 10-20 parts of mineral oil, and 0.5-1 parts of antioxidant. The rare earth Ce-OP core-shell structure halogen-free flame retardant comprises a rare earth cerium phenylphosphonate compound and a phosphorus-nitrogen halogen-free flame retardant, wherein the rare earth cerium phenylphosphonate compound is added in a proportion of 0.5-2.0 parts.

2. A rare earth Ce-O-P core-shell structure coated TPU flame retardant material, characterized in that: It comprises the following components by weight: 50-80 parts polyester TPU, 20-40 parts rare earth Ce-OP core-shell structure halogen-free flame retardant, 2-5 parts compatibilizer and dispersant, 10-20 parts mineral oil, and 0.5-1 parts antioxidant. The rare earth Ce-OP core-shell structure halogen-free flame retardant comprises a rare earth cerium phenylphosphonate compound and a phosphorus-nitrogen halogen-free flame retardant, wherein the rare earth cerium phenylphosphonate compound is added in a proportion of 0.5-2.0 parts.

3. The rare-earth Ce-OP core-shell structure TPU-coated flame-retardant material according to claim 1 or 2, characterized in that: The phenylphosphonic rare earth cerium compound is composed of any one of phenylphosphonic acid, diphenylphosphonic acid, (4-aminophenyl)phosphonic acid, and (2-aminophenyl)phosphonic acid, combined with any one of cerium nitrate hexahydrate, cerium chloride hexahydrate, cerium acetate hydrate, cerium acetylacetone hydrate, and cerium acetate hydrate.

4. The rare-earth Ce-OP core-shell structure TPU-coated flame-retardant material according to claim 1 or 2, characterized in that: The halogen-free flame retardant is selected from at least one of FR140A, FR140B, FR140N, and FR1400, or at least two of aluminum diethylphosphonate, aluminum hypophosphite, melamine cyanurate, piperazine pyrophosphate, aluminum phosphite, boric acid, rare earth elements, metal hydroxides, and metal oxides, or 90-98% carrier-free flame retardant masterbatch. 5.The rare earth Ce-O-P core-shell structure coated TPU flame-retardant material of claim 1 or 2, characterized in that: The compatibilizer and dispersant is at least one of the following: trinonyl trimellitate, di(butoxyethoxyethyl) adipic acid, trioctyl trimellitate, terminal polyisobutylene, and copolymer of propylene oxide and ethylene oxide. 6.The rare earth Ce-O-P core-shell structure coated TPU flame-retardant material of claim 1 or 2, characterized in that: The mineral oil is selected from at least one of aromatic oil, naphthenic oil, and paraffin oil.

7. The rare-earth Ce-OP core-shell structure TPU-coated flame-retardant material according to claim 1 or 2, characterized in that: The antioxidant is selected from at least one of antioxidant 168, antioxidant 1010, antioxidant 1076, and antioxidant DLTDP.

8. The preparation method of rare earth Ce-OP core-shell structure coated TPU flame retardant material according to claim 1 or 2, characterized in that: S1: Preparation of rare earth Ce-OP core-shell structured compounds: Phenylophosphonic acid and cerium compound were added to an ethanol-water mixed solvent with a mass ratio of 7:3 at a mass ratio of 1:(1.0-1.5). The mixture was reacted at 80-120℃ for 12-14 hours. After the reaction was completed, the mixture was washed with deionized water, filtered, and dried to obtain Ce-OP core-shell structured cerium phenylphosphonate. S2: Rare earth Ce-OP core-shell structure halogen-free flame retardant: Ce-OP core-shell phenylphosphonate, FR140N, titanate coupling agent, and aluminate coupling agent were added to a high-speed mixer at a mass ratio of 100:(850~950):(3-5):(3-5) and mixed at 80-120℃ and 500-1000 rpm for 10-30 min to obtain a rare earth Ce-OP core-shell halogen-free flame retardant. S3: Preparation of rare earth Ce-OP core-shell structured TPU flame retardant material: After drying polyether-type TPU or polyester-type TPU at 80-90℃ for 4-6 hours, it is mixed with the rare earth Ce-OP core-shell structure halogen-free flame retardant, compatibilizer, dispersant, mineral oil, and antioxidant obtained in step S2 according to the specified ratio for 10-30 minutes. Then, the mixture is melt-blended, extruded, cooled, granulated, and dried using a twin-screw extruder to obtain the rare earth Ce-OP core-shell structure coated TPU flame retardant material.

9. The preparation method according to claim 8, characterized in that: The process parameters of the twin-screw extruder in step S3 are as follows: screw length-to-diameter ratio L / D = 36:1-40:1, main machine speed 250-400 rpm, and processing temperature from zone one to the die head is 130-170℃, 140-190℃, and 160-200℃ respectively.

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