Flame-retardant heat-aging-resistant polyether TPU composite material, preparation method and application thereof

Abstract

This invention belongs to the technical field of thermoplastic polyurethane material modification technology, specifically relating to a flame-retardant and heat-aging resistant polyether TPU composite material, its preparation method, and its application. The raw materials of the polyether TPU composite material include the following components: polyether TPU, modified silicone oil, phosphorus-based charring flame retardant, nitrogen-based charring flame retardant, lubricant, and antioxidant. The modified silicone oil is prepared by the following method: amino silicone oil undergoes a nucleophilic addition reaction with a monofunctional epoxy compound; the resulting product I undergoes a ring-opening esterification reaction with maleic anhydride; the resulting product II is the modified silicone oil. The key to this invention lies in introducing a multifunctional modified silicone oil obtained through a specific two-step modification method and a phosphorus-nitrogen composite flame-retardant component. The resulting polyether TPU composite material not only possesses excellent mechanical properties but also exhibits high resistance to exudation and yellowing aging, demonstrating highly efficient non-drip flame retardant effect and heat aging resistance.

Description

Technical Field

[0001] This invention belongs to the technical field of thermoplastic polyurethane (TPU) material modification technology, specifically relating to a flame-retardant and heat-resistant polyether TPU composite material, its preparation method, and its application. Background Technology

[0002] Thermoplastic polyurethane (TPU) is a polymer material that combines the elasticity of rubber with the processability of plastics. Polyether-type TPU, in particular, is widely used in automotive wiring harnesses, electronic sheaths, special seals, and high-end cables due to its excellent low-temperature toughness, abrasion resistance, flexural strength, and processing fluidity. While polyether TPU's good overall performance makes it an important polymer substrate in high-end manufacturing, its inherent limitations restrict its application in demanding flame-retardant and temperature-resistant environments. For example, pure polyether TPU has a low limiting oxygen index, is prone to melting and dripping during high-temperature combustion, and lacks self-extinguishing properties, failing to meet the flame-retardant standards of high-end cables and electronic appliances. Furthermore, polyether TPU is susceptible to thermo-oxidative degradation under long-term high-temperature conditions, leading to a significant decrease in mechanical properties and yellowing and deterioration of appearance, making it difficult to simultaneously meet the dual requirements of flame retardancy and temperature resistance.

[0003] Current technologies for flame-retardant modification of polyether TPU mostly employ physical blending of flame-retardant additives. This method suffers from two major drawbacks: First, conventional flame retardants have poor compatibility with the polyether TPU matrix, easily leading to additive precipitation and surface blooming during processing and use. This not only affects the material's appearance but also causes a sharp drop in the matrix's mechanical properties. Second, ordinary flame-retardant systems can only achieve single-phase gas-phase flame retardancy. During combustion, they cannot form a continuous and dense heat-insulating and oxygen-barrier char layer, resulting in low flame-retardant efficiency, poor drip suppression, difficulty in achieving self-supporting char formation, and insufficient high-temperature flame-retardant durability. Furthermore, conventional modifying additives have limited functionality and cannot simultaneously achieve multiple benefits such as matrix compatibility, flame-retardant synergy, and resistance to heat aging, thus restricting the large-scale application of polyether TPU in high-end high-temperature flame-retardant applications.

[0004] Recent publicly disclosed patent technologies, such as Chinese patent applications with publication numbers CN116285305B and CN119684778A, all focus on optimizing flame-retardant systems to improve flame retardancy ratings or mechanical properties. However, they generally neglect the exudation resistance of flame-retardant additives under high-temperature conditions and the long-term heat aging resistance of materials. This results in modified materials still facing performance degradation and appearance deterioration during long-term use. Even when some technologies attempt to improve a single property by adding multiple additives, they suffer from drawbacks such as complex formulations, poor synergy between components, and increased costs, failing to achieve the goal of highly efficient modification with "one additive for multiple functions." Summary of the Invention

[0005] One of the objectives of this invention is to address the problems of existing polyether TPU modified materials, such as easy release of flame retardants under high-temperature conditions, poor flame retardant effect, and poor long-term heat aging resistance. The invention provides a polyether TPU composite material that not only has good mechanical properties but also high resistance to release and high resistance to heat aging.

[0006] Specifically, the raw materials of the polyether TPU composite material include the following components: polyether TPU, modified silicone oil, phosphorus-based char-forming flame retardant, nitrogen-based char-forming flame retardant, lubricant, and antioxidant; the modified silicone oil is prepared by the following method: amino silicone oil undergoes a nucleophilic addition reaction with a monofunctional epoxy compound, and the resulting reaction product I undergoes a ring-opening esterification reaction with maleic anhydride, and the resulting reaction product II is the modified silicone oil, wherein the molar ratio of amino groups in the amino silicone oil to epoxy groups in the monofunctional epoxy compound is 1:(0.4~0.6); the monofunctional epoxy compound is compound A having the structure shown in formula (1) and / or compound B having the structure shown in formula (2): Equation (1), Equation (2), In formulas (1) and (2), R1 is a C1-C5 alkyl group, R2 is a C1-C5 alkylene group, and R3 is a C1-C5 alkyl group or a C2-C8 alkenyl group; the antioxidant is a hindered phenolic primary antioxidant and a phosphite secondary antioxidant.

[0007] In a preferred embodiment, based on 100 parts by weight of polyether TPU, the amount of modified silicone oil is 0.5-2 parts by weight, the amount of phosphorus-based charring flame retardant is 10-25 parts by weight, the amount of nitrogen-based charring flame retardant is 4-10 parts by weight, the amount of lubricant is 0.3-1 parts by weight, the amount of hindered phenolic primary antioxidant is 0.3-0.5 parts by weight, and the amount of phosphite secondary antioxidant is 0.1-0.3 parts by weight.

[0008] In a preferred embodiment, the amino silicone oil is a polydimethylsiloxane containing side-amino and / or terminal amino groups, with an amine value of 0.6~1.2 mmol / g and a viscosity of 400~1000 mPa. s.

[0009] In a preferred embodiment, compound A is selected from at least one of propylene oxide, 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, and 1,2-epoxyheptane.

[0010] In a preferred embodiment, compound B is selected from at least one of n-butyl glycidyl ether, glycidyl methyl ether, ethyl glycidyl ether, isopropyl glycidyl ether, 2,3-epoxypropane pentyl ether, allyl alcohol glycidyl ether, methyl allyl glycidyl ether, and butenyl glycidyl ether.

[0011] In a preferred embodiment, the conditions for the nucleophilic addition reaction include: an inert gas atmosphere, a temperature of 70-80°C, and a time of 2-3 hours.

[0012] In a preferred embodiment, the molar ratio of the amino group in the amino silicone oil to the sum of the epoxy group and maleic anhydride in the monofunctional epoxy compound is 1:(1.0~1.2).

[0013] In a preferred embodiment, the conditions for the ring-opening esterification reaction include: an inert gas atmosphere, a temperature of 60~70°C, and a time of 2~3 hours.

[0014] In a preferred embodiment, the phosphorus-based char-forming flame retardant is selected from at least one of diethylaluminum hypophosphite, aluminum hypophosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide.

[0015] In a preferred embodiment, the nitrogen-based char-forming flame retardant is melamine cyanurate and / or melamine phosphate.

[0016] In a preferred embodiment, the lubricant is a fatty amide lubricant.

[0017] The second objective of this invention is to provide a method for preparing the aforementioned flame-retardant and heat-resistant TPU composite material. The preparation method includes: mixing polyether TPU, modified silicone oil, phosphorus-based charring flame retardant, nitrogen-based charring flame retardant, lubricant, and antioxidant to obtain a premix; then, the premix is ​​melt-blended and extruded into granules using a twin-screw extruder to obtain the flame-retardant and heat-resistant TPU composite material.

[0018] In a preferred embodiment, the mixing process is carried out at a temperature of 80-90°C and a rotation speed of 200-300 rpm for 5-10 minutes.

[0019] In a preferred embodiment, the twin-screw extruder is set to a temperature of 165~220℃ and a screw speed of 200~300rpm.

[0020] A third objective of this invention is to provide the application of the above-mentioned flame-retardant and heat-resistant polyether TPU composite material in the preparation of heat-resistant and flame-retardant materials for high-end cables, electronic appliances, and automotive parts.

[0021] Beneficial effects: The key to this invention lies in introducing a polyfunctional modified silicone oil with a specific structure obtained by sequentially modifying a monofunctional epoxy compound and maleic anhydride, and a phosphorus-nitrogen compound flame retardant component to modify the polyether TPU matrix material for flame retardancy and temperature resistance. The resulting polyether TPU composite material not only retains the mechanical properties of the polyether TPU matrix material itself, exhibiting good tensile strength and high elongation at break, but also has high resistance to exudation and yellowing aging under high temperature conditions, demonstrating highly efficient non-drip flame retardant effect and heat aging resistance. The reason for this is speculated to be that the modified silicone oil obtained by sequentially modifying it with monofunctional epoxy compounds and maleic anhydride contains secondary amino (-NH-), hydroxyl, carboxyl, and unsaturated C=C double bonds. This enhances the hydrogen bonding between the modified silicone oil and the polyether TPU matrix and the phosphorus-nitrogen composite flame retardant components, improving the interfacial bonding between components and solving the problems of easy precipitation and blooming of traditional flame retardants. Furthermore, the unsaturated C=C double bonds can undergo covalent grafting reactions with the free radicals and isocyanate residues of the TPU molecular chain, bonding the modified silicone oil to the TPU matrix and solving the problem of silicone oil migration and precipitation. Simultaneously, the unsaturated C=C double bonds can also undergo addition reactions with the active amino groups of nitrogen-based char-forming flame retardants, further enhancing the interfacial bonding. Thus, through the hydrogen and covalent bonds formed between the modified silicone oil and the polyether TPU matrix and the phosphorus-nitrogen composite flame retardant components, the overall effect is improved. Simultaneously achieving multiple functions such as improved compatibility, synergistic flame retardancy, anti-exudation, and anti-aging; phosphorus-based char-forming flame retardants can catalyze the dehydration of the substrate to form an initial char layer skeleton, nitrogen-based char-forming flame retardants release inert gases and generate alkaline catalytic substances to accelerate the cross-linking of the char layer, and modified silicone oil can further promote the densification of the char layer. Thus, under the efficient synergistic effect of phosphorus-nitrogen compound flame retardant components and modified silicone oil, the material can quickly form a continuous, dense, and high-temperature resistant self-supporting char layer during combustion, achieving efficient drip-free flame retardancy; the polyether TPU composite material provided by this invention also incorporates an antioxidant component composed of hindered phenolic primary antioxidant and phosphite secondary antioxidant, which, together with modified silicone oil, constructs a long-lasting anti-heat aging system. By effectively capturing free radicals and decomposing hydrogen peroxide, it delays the aging and degradation of the material under high-temperature conditions, exhibiting excellent long-lasting resistance to yellowing and anti-heat aging performance. In summary, the polyether TPU composite material provided by this invention has excellent comprehensive performance. It can not only effectively retain the mechanical properties of the polyether TPU matrix itself, but also has no blooming problem after 72 hours at a high temperature of 85℃. It can also achieve non-dripping flame retardancy and long-term anti-yellowing and aging performance. It has a wide range of applications and can be used in high-end cables, electronic appliances, automotive parts and other fields with strict requirements for flame retardancy and temperature resistance, and has good market application prospects. Detailed Implementation

[0022] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Furthermore, unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of the present invention.

[0023] The raw materials for the polyether TPU composite material provided by this invention include the following components: polyether TPU, modified silicone oil, phosphorus-based char-forming flame retardant, nitrogen-based char-forming flame retardant, lubricant, and antioxidant. The modified silicone oil is prepared by the following method: amino silicone oil undergoes a nucleophilic addition reaction with a monofunctional epoxy compound; the resulting reaction product I undergoes a ring-opening esterification reaction with maleic anhydride; the resulting reaction product II is the modified silicone oil.

[0024] In the preparation process of the modified silicone oil, the molar ratio of amino groups in the amino silicone oil to epoxy groups in the monofunctional epoxy compound is 1:(0.4~0.6), such as 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, or any ratio between them. In this case, some of the amino groups in the amino silicone oil first undergo a nucleophilic addition reaction with the epoxy groups in the monofunctional epoxy compound, and the remaining amino groups then undergo a ring-opening esterification reaction with maleic anhydride, thereby preparing a multifunctional modified silicone oil containing hydroxyl, carboxyl, and unsaturated C=C double bonds. Introducing this modified silicone oil into polyether TPU composites is beneficial for enhancing the hydrogen bonding between the polyether TPU matrix and the phosphorus-nitrogen compound flame-retardant components, improving the compatibility between the components in the system, and giving the polyether TPU composites good tensile strength and high elongation at break, while also exhibiting high resistance to exudation and high resistance to heat aging under high-temperature conditions.

[0025] In the preparation process of the modified silicone oil described above, the monofunctional epoxy compound is compound A having the structure shown in formula (1) and / or compound B having the structure shown in formula (2): Equation (1), Equation (2), In formulas (1) and (2), R1 is a C1-C5 alkyl group, R2 is a C1-C5 alkylene group, and R3 is a C1-C5 alkyl group or a C2-C8 alkenyl group. Specific examples of C1-C5 alkyl groups include, but are not limited to: -CH3, -CH2CH3, -CH2CH2CH3, -CH(CH3)2, -CH2CH2CH2CH3, -CH(CH3)CH2CH3, -CH2CH(CH3)CH3, -C(CH3)3, -CH2CH2CH2CH2CH3, -CH(CH3)CH2CH2CH3, -CH2CH(CH3)CH3, -CH2CH2CH(CH3)CH3, -CH2CH2CH(CH3)2, -CH(CH3)CH(CH3)CH3, -CH(CH2CH3)2, -CH2CH(CH2CH3)CH3, -CH2C(CH3)3, etc. Specific examples of C1~C5 alkylene groups include, but are not limited to: -CH2-, -CH2CH2-, -CH2CH2CH2-, -C(CH3)2-, -CH2CH2CH2CH2-, -CH(CH3)CH2CH2-, -CH2CH(CH3)CH2-, -C(CH3)2CH2-, -CH2CH2CH2CH2CH2-, -CH(CH3)CH2CH2-, -CH(CH3)CH(CH3)CH2-, -C(CH2CH3)2-, -CH(CH2CH3)CH2CH2-, -CH2CH(CH2CH3)CH2-, -CH2C(CH3)2CH2-, etc. Specific examples of C2~C8 alkenes include, but are not limited to: -CH=CH2, -CH2CH=CH2, -(CH3)C=CH2, -CH2CH2CH=CH2, -CH2CH=CHCH3, -CH=C(CH3)2, -(CH2)3CH=CH2, -(CH2)4CH=CH2, -(CH2)5CH=CH2, -(CH2)6CH=CH2, etc.

[0026] In this invention, based on 100 parts by weight of polyether TPU, the amount of modified silicone oil is preferably 0.5 to 2 parts by weight, such as 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2 parts by weight or any value between them; the amount of phosphorus-based char-forming flame retardant is preferably 10 to 25 parts by weight, such as 10, 12, 15, 18, 20, 22, 25 parts by weight or any value between them; the amount of nitrogen-based char-forming flame retardant is preferably 4 to 10 parts by weight, such as 4, 5, 6, 7, 8, 9, 10 parts by weight. The amount of the lubricant is preferably 0.3 to 1 part by weight, such as 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, or 1 part by weight, or any value between them; the amount of the hindered phenolic primary antioxidant is preferably 0.3 to 0.5 parts by weight, such as 0.3, 0.4, or 0.5 parts by weight, or any value between them; the amount of the phosphite secondary antioxidant is preferably 0.1 to 0.3 parts by weight, such as 0.1, 0.2, or 0.3 parts by weight, or any value between them. When the amounts of each original component are within the above-mentioned preferred ranges, it is more conducive to exerting the synergistic effect between the modified silicone oil, phosphorus-based char-forming flame retardant, nitrogen-based char-forming flame retardant, and antioxidant, thereby improving the mechanical properties, anti-exudation properties under high-temperature conditions, and yellowing aging resistance of the polyether TPU composite material.

[0027] In this invention, the amino silicone oil can be a polydimethylsiloxane containing side-amino groups and / or terminal amino groups, that is, it can be a polydimethylsiloxane containing only side-amino groups, a polydimethylsiloxane containing only terminal amino groups, or a polydimethylsiloxane containing both side-amino groups and terminal amino groups, or a mixture of polydimethylsiloxane containing only side-amino groups and polydimethylsiloxane containing only terminal amino groups. The amine value of the amino silicone oil is preferably 0.6~1.2 mmol / g, such as 0.6 mmol / g, 0.8 mmol / g, 1.0 mmol / g, 1.2 mmol / g, or any value between them. The viscosity of the amino silicone oil is preferably 400~1000 mPa. s, such as 400mPa s, 600mPa s, 800mPa s, 1000mPa s or any value between them.

[0028] In this invention, compound A can be any compound having the structure shown in formula (1), and specific examples include, but are not limited to, any one or more of propylene oxide, 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, and 1,2-epoxyheptane.

[0029] In this invention, compound B can be any compound having the structure shown in formula (2), and specific examples include, but are not limited to, any one or more of the following: n-butyl glycidyl ether, glycidyl methyl ether, ethyl glycidyl ether, isopropyl glycidyl ether, 2,3-epoxypropane pentyl ether (CAS No.: 121906-42-1), allyl alcohol glycidyl ether, methyl allyl glycidyl ether, and butenyl glycidyl ether. When the monofunctional epoxy compound is compound B, it can further introduce flexible aliphatic segments containing ether bonds into the modified silicone oil, which is beneficial to further improve the flexibility of the material. When R3 in compound B is more preferably an alkenyl group of C2 to C8, unsaturated double bonds are introduced at the same time as the flexible aliphatic segments containing ether bonds, which is beneficial to further improve the compatibility between the modified silicone oil and polyether TPU, phosphorus-based char-forming flame retardants, and nitrogen-based char-forming flame retardants, thereby improving the mechanical properties, anti-exudation properties, flame retardant properties, and anti-yellowing aging properties of polyether TPU composite materials.

[0030] In this invention, the amino silicone oil preferably undergoes a dehydration treatment before undergoing a nucleophilic addition reaction with a monofunctional epoxy compound. In one specific embodiment, the dehydration treatment method may be: vacuum treatment of the amino silicone oil at 80~100°C for 0.5~2.0h. The conditions for the nucleophilic addition reaction preferably include: an inert gas atmosphere; a temperature of 70~80°C, such as 70°C, 72°C, 75°C, 78°C, 80°C or any value between them; and a time of 2~3h, such as 2h, 2.5h, 3h or any value between them.

[0031] In this invention, the molar ratio of the amino group in the amino silicone oil to the sum of the epoxy group and maleic anhydride in the monofunctional epoxy compound is preferably 1:(1.0~1.2), such as 1:1.0, 1:1.05, 1:1.1, 1:1.15, 1:1.2, or any ratio between them. The purpose here is to ensure that the amino group in the amino silicone oil reacts fully, thereby better obtaining a multifunctional silicone oil modified with hydroxyl, carboxyl, and unsaturated C=C double bonds. In this invention, the preferred conditions for the ring-opening esterification reaction include: an inert gas atmosphere; a temperature of 60~70℃, such as 60℃, 62℃, 65℃, 68℃, 70℃ or any value between them; and a time of 2~3h, such as 2h, 2.5h, 3h or any value between them.

[0032] In this invention, the phosphorus-based charring flame retardant can be a conventional choice in the art; that is, the phosphorus-based charring flame retardant can be entirely selected from phosphorus-based flame retardants containing pH bonds, entirely selected from phosphorus-based flame retardants without pH bonds, or a mixture of phosphorus-based flame retardants containing pH bonds and those without pH bonds. Specific examples of the phosphorus-based flame retardants include, but are not limited to, any one or more of aluminum hypophosphite (AHP), 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide (DOPS). Specific examples of the phosphorus-based flame retardants without pH bonds include, but are not limited to, any one or more of diethylaluminum hypophosphite (ADP), ammonium polyphosphate, and phosphate esters (such as bisphenol A-bis(diphenyl phosphate) (BDP), resorcinol bis(diphenyl phosphate) (RDP), etc.).

[0033] In this invention, the nitrogen-based char-forming flame retardant can be a conventional choice in the art, and is more preferably melamine cyanurate and / or melamine phosphate. In this case, the active amino groups on the melamine can undergo addition with the C=C double bonds, further enhancing the interfacial bonding force, better solving the material compatibility problem, and improving the anti-precipitation performance.

[0034] In this invention, the lubricant can be any lubricant commonly used in the art, and more preferably a fatty amide lubricant, including but not limited to any one or more of stearamide, oleamide, ethylene bis-stearamide (EBS), hexamethylene bis-dodecyl stearamide, and diethanolamide of oleic acid.

[0035] In this invention, the antioxidants are hindered phenolic primary antioxidants and phosphite secondary antioxidants. Specific examples of the hindered phenolic primary antioxidants include, but are not limited to, any one or more of the following: antioxidant 1010, antioxidant 1076, antioxidant 1098, antioxidant 3114, antioxidant 330, antioxidant 245, antioxidant 1330, antioxidant 1135, antioxidant 1024, and antioxidant 1520. Specific examples of the phosphite secondary antioxidants include, but are not limited to, any one or more of the following: antioxidant 168, antioxidant 626, antioxidant 636, tetraphenyldipropylene glycol diphosphite (THOP), and trinonylphenyl phosphite (TNPP).

[0036] This invention provides a method for preparing the flame-retardant and heat-resistant TPU composite material described above. The preparation method includes: mixing polyether TPU, modified silicone oil, phosphorus-based charring flame retardant, nitrogen-based charring flame retardant, lubricant, and antioxidant to obtain a premix; then, the premix is ​​melt-blended and extruded granulated using a twin-screw extruder to obtain the flame-retardant and heat-resistant TPU composite material.

[0037] In this invention, the preparation method preferably further includes: pre-drying the polyether TPU before mixing. In one specific embodiment, the pre-drying treatment involves baking the polyether TPU at 80-90°C for 2-6 hours. The mixing process can be carried out in a high-speed mixer. The mixing process is performed at a temperature of 80-90°C and a rotation speed of 200-300 rpm for 5-10 minutes. The mixing temperature can be 80°C, 82°C, 85°C, 88°C, 90°C, or any value between them. The mixing speed can be 200 rpm, 220 rpm, 250 rpm, 280 rpm, 300 rpm, or any value between them. The mixing time can be 5 minutes, 6 minutes, 7 minutes, 8 minutes, 9 minutes, 10 minutes, or any value between them.

[0038] In this invention, the temperature of the twin-screw extruder is preferably set to 165~220℃, such as 165℃, 170℃, 180℃, 190℃, 200℃, 210℃, 220℃ or any value between them; the screw speed is preferably 200~300rpm, such as 200rpm, 220rpm, 250rpm, 280rpm, 300rpm or any value between them. The temperature of the twin-screw extruder is preferably set using a segmented temperature control method, which can be divided into a feeding section, a melting section, a homogenizing section, and a die head section.

[0039] The present invention will be described in detail below through specific embodiments. These embodiments are intended to explain the invention and should not be construed as limiting it. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0040] Preparation Example 1: Preparation of Modified Silicone Oil Take 100.00g of amino silicone oil (amine value 0.8mmol / g, viscosity 600mPa). S, a side-amino polydimethylsiloxane, was added to the reactor. Under nitrogen protection, the temperature was raised to 90°C and evacuated for 45 minutes. Then, the temperature was lowered to 60°C, and 2.32 g (40 mmol) of propylene oxide was slowly added dropwise over 45 minutes. The temperature was then raised to 75°C and held for 2.5 hours to complete the nucleophilic addition reaction. The temperature was lowered to 55°C, and 3.92 g (40 mmol) of maleic anhydride was added in batches (each batch not exceeding 2 g, and the next batch was added after the previous batch had dissolved, the same below). The temperature was held at 65°C for 2.5 hours to complete the ring-opening esterification reaction. The low-boiling substances were removed by evacuation for 30 minutes, and the modified silicone oil, denoted as S1, was discharged and sealed for later use.

[0041] Preparation Example 2: Preparation of Modified Silicone Oil Take 100.00g of amino silicone oil (amine value 0.6mmol / g, viscosity 400mPa). (s, amino-terminated polydimethylsiloxane) was added to the reactor, and under nitrogen protection, the temperature was raised to 90°C, then evacuated for 30 minutes, and finally cooled to 60°C. 1.73 g (24 mmol) of 1,2-epoxybutane was slowly added dropwise over 30 min. The temperature was raised to 70 °C and held for 2 h to complete the nucleophilic addition reaction. The temperature was lowered to 50 °C, and 3.53 g (36 mmol) of maleic anhydride was added in portions. The reaction was held at 60 °C for 2 h to complete the ring-opening reaction. The low-boiling substances were removed by vacuuming for 30 min. The modified silicone oil, denoted as S2, was discharged and sealed for later use.

[0042] Preparation Example 3: Preparation of Modified Silicone Oil Take 100.00g of amino silicone oil (amine value 1.2mmol / g, viscosity 1000mPa). S, a side-amino polydimethylsiloxane, was added to the reactor. Under nitrogen protection, the temperature was raised to 90°C and evacuated for 60 min. Then, the temperature was lowered to 60°C, and 6.20 g (72 mmol) of 1,2-epoxypentane was slowly added dropwise over 60 min. After the addition was completed, the temperature was raised to 80°C and held for 3 h to complete the nucleophilic addition reaction. The temperature was lowered to 60°C, and 4.71 g (48 mmol) of maleic anhydride was added in batches. The temperature was held at 70°C for 3 h to complete the ring-opening reaction. The low-boiling substances were removed by evacuation for 30 min, and the modified silicone oil, designated as S3, was discharged and sealed for later use.

[0043] Preparation Example 4: Preparation of Modified Silicone Oil Take 100.00g of amino silicone oil (amine value 0.8mmol / g, viscosity 600mPa). S, a side-amino polydimethylsiloxane, was added to the reactor. Under nitrogen protection, the temperature was raised to 90°C and evacuated for 45 minutes. Then, the temperature was lowered to 60°C, and 5.21 g (40 mmol) of n-butyl glycidyl ether was slowly added dropwise over 45 minutes. The temperature was then raised to 75°C and held for 2.5 hours to complete the nucleophilic addition reaction. The temperature was lowered to 55°C, and 3.92 g (40 mmol) of maleic anhydride was added in batches. The temperature was then held at 65°C for 2.5 hours to complete the ring-opening esterification reaction. The low-boiling substances were removed by evacuation for 30 minutes, and the modified silicone oil, designated S4, was discharged and sealed for later use.

[0044] Preparation Example 5: Preparation of Modified Silicone Oil Take 100.00g of amino silicone oil (amine value 0.8mmol / g, viscosity 600mPa). S, a side-amino polydimethylsiloxane, was added to the reactor. Under nitrogen protection, the temperature was raised to 90°C and evacuated for 45 minutes. Then, the temperature was lowered to 60°C, and 6.92 g (48 mmol) of 2,3-epoxypropane pentyl ether was slowly added dropwise over 45 minutes. The temperature was then raised to 75°C and held for 2.5 hours to complete the nucleophilic addition reaction. The temperature was lowered to 55°C, and 3.14 g (32 mmol) of maleic anhydride was added in batches. The temperature was then held at 65°C for 2.5 hours to complete the ring-opening esterification reaction. The low-boiling substances were removed by evacuation for 30 minutes, and the modified silicone oil, designated S5, was discharged and sealed for later use.

[0045] Preparation Example 6: Preparation of Modified Silicone Oil Take 100.00g of amino silicone oil (amine value 0.8mmol / g, viscosity 600mPa). S (a side-amino polydimethylsiloxane) was added to the reactor. Under nitrogen protection, the temperature was raised to 90°C and evacuated for 45 min. Then, the temperature was lowered to 60°C, and 3.65 g (32 mmol) of allyl alcohol glycidyl ether was slowly added dropwise over 45 min. The temperature was then raised to 75°C and held for 2.5 h to complete the nucleophilic addition reaction. The temperature was lowered to 55°C, and 4.71 g (48 mmol) of maleic anhydride was added in batches. The temperature was then held at 65°C for 2.5 h to complete the ring-opening esterification reaction. The low-boiling substances were removed by evacuation for 30 min, and the modified silicone oil, designated S6, was discharged and sealed for later use.

[0046] Comparative Preparation Example 1: Preparation of Reference Modified Silicone Oil Take 100.00g of amino silicone oil (amine value 0.8mmol / g, viscosity 600mPa). s, side-amino polydimethylsiloxane) was added to the reactor. Under nitrogen protection, the temperature was raised to 90°C and evacuated for 45 min. Then, the temperature was lowered to 60°C, and 2.32 g (40 mmol) of propylene oxide was slowly added dropwise. After the addition was completed in 45 min, the temperature was raised to 75°C and held for 2.5 h to complete the nucleophilic addition reaction. The temperature was lowered to 55°C, and 4.00 g (40 mmol) of succinic anhydride was added in batches. The temperature was held at 65°C for 2.5 h to complete the ring-opening esterification reaction. The low-boiling substances were removed by evacuation for 30 min, and the modified silicone oil, denoted as DS1, was discharged and sealed for later use.

[0047] Example 1: Preparation of polyether TPU composite material Raw material pretreatment: Place polyether TPU-1 (Shore hardness 90A, elongation at break 450%) in an 85℃ oven and bake for 4 hours to remove moisture; Preparation of the mixture: By mass, take 100.0 parts of dried polyether TPU-1, 1.0 parts of modified silicone oil S1 from Preparation Example 1, 18.0 parts of aluminum diethyl phosphite, 8.0 parts of melamine cyanurate, 0.3 parts of EBS, 0.4 parts of antioxidant 1010, and 0.2 parts of antioxidant 168, add them to a high-speed mixer, and mix for 8 minutes at 85°C and 250 rpm to obtain a uniformly dispersed premix. Blending and granulation: The premixed material is fed into a twin-screw extruder with segmented temperature control: 185°C for the feeding section, 200°C for the melting section, 205°C for the homogenization section, and 208°C for the die head. The screw speed is 250 rpm. After melt blending, the material is extruded, stretched, cooled, granulated, and dried to obtain polyether TPU composite material particles.

[0048] Example 2 Preparation of polyether TPU composite material Raw material pretreatment: Place polyether TPU-2 (Shore hardness 85A, elongation at break 550%) in an 85℃ oven and bake for 4 hours to remove moisture; Preparation of the mixture: By mass, take 100.0 parts of dried polyether TPU-2, 0.5 parts of modified silicone oil S2 from Preparation Example 2, 12.0 parts of aluminum hypophosphite, 10.0 parts of melamine phosphate, 0.5 parts of EBS, 0.5 parts of antioxidant 1076, and 0.1 parts of antioxidant 168, add them to a high-speed mixer, and mix for 10 minutes at 80°C and 200 rpm to obtain a uniformly dispersed premix. Blending and granulation: The premixed material is fed into a twin-screw extruder with segmented temperature control: 180°C for the feeding section, 190°C for the melting section, 200°C for the homogenization section, and 205°C for the die head. The screw speed is 200 rpm. After melt blending, the material is extruded, stretched, cooled, granulated, and dried to obtain polyether TPU composite material particles.

[0049] Example 3 Preparation of polyether TPU composite material Raw material pretreatment: Place polyether TPU-3 (Shore hardness 95A, elongation at break 450%) in an 85℃ oven and bake for 4 hours to remove moisture; Preparation of the mixture: By mass, take 100.0 parts of dried polyether TPU-3, 2.0 parts of modified silicone oil S3 of Preparation Example 3, 25.0 parts of 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 8.0 parts of melamine polyphosphate, 1.0 part of erucamide, 0.3 parts of antioxidant 1010, and 0.3 parts of antioxidant 626, add them to a high-speed mixer, and mix for 5 minutes at 90°C and 300 rpm to obtain a uniformly dispersed premix. Blending and granulation: The premixed material is fed into a twin-screw extruder with segmented temperature control: 190°C for the feeding section, 205°C for the melting section, 210°C for the homogenization section, and 210°C for the die head. The screw speed is 300 rpm. After melt blending, the material is extruded, stretched, cooled, granulated, and dried to obtain polyether TPU composite material particles.

[0050] Example 4 Preparation of polyether TPU composite material Polyether TPU composite materials were prepared according to the method of Example 1, except that modified silicone oil S4 of Preparation Example 4 was used instead of modified silicone oil S1 of Preparation Example 1 in the same mass proportions, and all other conditions were the same as in Example 1. Polyether TPU composite material particles were thus prepared.

[0051] Example 5 Preparation of polyether TPU composite material Polyether TPU composite materials were prepared according to the method of Example 2, except that the modified silicone oil S5 of Preparation Example 5 was used instead of the modified silicone oil S1 of Preparation Example 1 in the same mass parts, and all other conditions were the same as in Example 2. Polyether TPU composite material particles were thus prepared.

[0052] Example 6 Preparation of polyether TPU composite material Polyether TPU composite materials were prepared according to the method of Example 3, except that the modified silicone oil S6 of Preparation Example 6 was used instead of the modified silicone oil S1 of Preparation Example 1 in the same mass parts, and all other conditions were the same as in Example 3. Polyether TPU composite material particles were thus prepared.

[0053] Comparative Example 1: Preparation of Reference Polyether TPU Composite Material The reference polyether TPU composite material was prepared according to the method of Example 1, except that the amount of modified silicone oil S1 added in Example 1 was 0, and the other conditions were the same as in Example 1. The reference polyether TPU composite material particles were thus prepared.

[0054] Comparative Example 2: Preparation of Reference Polyether TPU Composite Material The reference polyether TPU composite material was prepared according to the method in Example 1, except that the same mass fraction of amino silicone oil (amine value 0.8 mmol / g, viscosity 600 mPa) was used. The reference polyether TPU composite particles were prepared by replacing the modified silicone oil S1 in Preparation Example 1 with s (side amino polydimethylsiloxane), and all other conditions were the same as in Example 1.

[0055] Comparative Example 3: Preparation of Reference Polyether TPU Composite Material The reference polyether TPU composite material was prepared according to the method of Example 1, except that the same mass parts of the reference modified silicone oil DS1 of the comparative preparation example 1 were used instead of the modified silicone oil S1 of the preparation example 1. All other conditions were the same as in Example 1. The reference polyether TPU composite material particles were thus prepared.

[0056] Test case The polyether TPU composite materials prepared in the above examples and comparative examples were tested for flame retardancy, yellowing resistance, mechanical properties, exudation properties and oxygen index according to the following methods. The specific results are shown in Table 1.

[0057] (1) Flame retardant performance: The polyether TPU composite materials prepared in each example and comparative example were processed into standard strips with a thickness of 1.6 mm. The vertical burning performance was tested according to UL94 standard to evaluate the flame retardant level.

[0058] (2) Yellowing resistance: The polyether TPU composite materials prepared in each example and comparative example were processed into 2mm thick standard samples and placed in a 135℃ heat aging chamber for 168h. The colorimetric coordinates were measured by an instrument using a D65 light source according to the method in ASTM D2244 standard, and the color difference (ΔE) before and after aging was finally calculated. The yellowing resistance was evaluated according to the magnitude of the yellowing ΔE. The smaller the ΔE, the better the yellowing resistance.

[0059] (3) Mechanical properties: The polyether TPU composite materials prepared in each example and comparative example were prepared into tensile specimens according to GB / T528-2009 standard. The tensile strength and elongation at break were tested using an electronic tensile testing machine (model: CMT6104) at a test speed of 500 mm / min. Five specimens were tested for each group of samples. The original test data and stress-strain spectrum of each specimen were retained, and the average value was taken as the final test result.

[0060] (4) Additive precipitation performance: The polyether TPU composite material samples prepared in each example and comparative example were placed in an oven at 85°C for 168 hours. After being taken out and cooled to room temperature, the surface of the sample was observed by visual inspection to see whether precipitation or blooming occurred. The evaluation level was no precipitation, slight precipitation, and obvious blooming.

[0061] (5) Oxygen index test: The polyether TPU composite materials prepared in each example and comparative example were used to prepare type IV oxygen index standard samples according to GB / T2406.2-2009 standard. The samples were conditioned at a temperature of (23±2)℃ and a relative humidity of (50±5%) for no less than 88h. The oxygen index was tested using the top surface ignition method with a Jiangning oxygen index tester, and the combustion performance was evaluated.

[0062] Table 1

[0063] As shown in Table 1, compared with the comparative examples, the polyether TPU composite materials prepared in Examples 1-6 of this invention have excellent tensile strength and elongation at break, i.e., excellent mechanical properties. They also have a higher oxygen index, better flame retardant effect, better resistance to exudation and yellowing.

[0064] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. A flame-retardant heat-aging resistant polyether TPU composite material, characterized in that, The raw materials of the polyether TPU composite material include the following components: polyether TPU, modified silicone oil, phosphorus-based char-forming flame retardant, nitrogen-based char-forming flame retardant, lubricant, and antioxidant; the modified silicone oil is prepared by the following method: amino silicone oil undergoes a nucleophilic addition reaction with a monofunctional epoxy compound, and the resulting reaction product I undergoes a ring-opening esterification reaction with maleic anhydride, and the resulting reaction product II is the modified silicone oil, wherein the molar ratio of amino groups in the amino silicone oil to epoxy groups in the monofunctional epoxy compound is 1:(0.4~0.6); the monofunctional epoxy compound is compound A having the structure shown in formula (1) and / or compound B having the structure shown in formula (2): formula (1), formula (2), In formulas (1) and (2), R1 is a C1~C5 alkyl group, R2 is a C1~C5 alkylene group, and R3 is a C1~C5 alkyl group or a C2~C8 alkenyl group; The antioxidants are hindered phenolic primary antioxidants and phosphite secondary antioxidants.

2. The flame retardant heat-aging resistant polyether TPU composite material according to claim 1, characterized in that, Based on 100 parts by weight of polyether TPU, the amount of modified silicone oil is 0.5-2 parts by weight, the amount of phosphorus-based charring flame retardant is 10-25 parts by weight, the amount of nitrogen-based charring flame retardant is 4-10 parts by weight, the amount of lubricant is 0.3-1 parts by weight, the amount of hindered phenolic primary antioxidant is 0.3-0.5 parts by weight, and the amount of phosphite secondary antioxidant is 0.1-0.3 parts by weight.

3. The flame retardant heat-aging resistant polyether TPU composite material according to claim 1, characterized in that, The amino silicone oil is a polydimethylsiloxane containing side amino groups and / or terminal amino groups, with an amine value of 0.6-1.2 mmol / g and a viscosity of 400-1000 mPa s; Preferably, compound A is selected from at least one of propylene oxide, 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, and 1,2-epoxyheptane; Preferably, compound B is selected from at least one of n-butyl glycidyl ether, glycidyl methyl ether, ethyl glycidyl ether, isopropyl glycidyl ether, 2,3-epoxypropane pentyl ether, allyl alcohol glycidyl ether, methyl allyl glycidyl ether, and butenyl glycidyl ether.

4. The flame retardant heat-aging resistant polyether TPU composite material according to claim 1, characterized in that, The conditions for the nucleophilic addition reaction include: an inert gas atmosphere, a temperature of 70~80℃, and a time of 2~3h.

5. The flame retardant heat-aging resistant polyether TPU composite material according to claim 1, characterized in that, The molar ratio of the amino group in the amino silicone oil to the sum of the epoxy group and maleic anhydride in the monofunctional epoxy compound is 1:(1.0~1.2). Preferably, the conditions for the ring-opening esterification reaction include: an inert gas atmosphere, a temperature of 60~70℃, and a time of 2~3h.

6. The flame retardant heat-aging resistant polyether TPU composite material according to claim 1, characterized in that, The phosphorus-based char-forming flame retardant is selected from at least one of diethyl aluminum hypophosphite, aluminum hypophosphite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-sulfide. Preferably, the nitrogen-based char-forming flame retardant is melamine cyanurate and / or melamine phosphate.

7. The flame retardant heat-aging resistant polyether TPU composite material according to claim 1, characterized in that, The lubricant is a fatty amide lubricant.

8. Process for the production of flame-retardant heat-aging resistant polyether TPU composites according to any one of claims 1 to 7, characterized in that, The preparation method includes: mixing polyether TPU, modified silicone oil, phosphorus-based char-forming flame retardant, nitrogen-based char-forming flame retardant, lubricant and antioxidant to obtain a premix, and then using a twin-screw extruder to melt-blend and extrude granulate the premix to obtain a flame-retardant and heat-resistant polyether TPU composite material.

9. The process for the preparation of flame retardant heat-aging resistant polyether TPU composite according to claim 8, characterized in that, The mixing treatment is carried out at a temperature of 80-90 DEG C and a rotation speed of 200-300 rpm for 5-10 min. Preferably, the temperature of the twin-screw extruder is set to 165-220 DEG C, and the screw rotation speed is 200-300 rpm.

10. Use of the flame-retardant heat-aging-resistant polyether TPU composite material according to any one of claims 1-7 in the preparation of temperature-resistant flame-retardant materials for high-end cables, electronic appliances, and automobile parts.

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