Halogen-free flame-retardant tracking-resistant polyurethane material and preparation method thereof

Abstract

The invention relates to the technical field of halogen-free flame-retardant polyurethane, in particular to a halogen-free flame-retardant tracking-resistant polyurethane material and a preparation method thereof, and aims at solving the problems that an existing polyurethane material is inflammable and poor in tracking resistance. According to the material, a thermoplastic polyurethane elastomer, a phosphorus-based flame retardant, layered nano zirconium phosphate, a tracking-resistant auxiliary agent, a flexibilizer, a flame-retardant assistant agent and a surface modifier are matched to prepare the halogen-free flame-retardant tracking-resistant polyurethane material with excellent flame retardance, tracking resistance and good matrix compatibility. The material can effectively overcome inherent defects such as weather resistance, fatigue resistance and the like of an existing charging pile cable, improves tracking agent resistance, flame retardance and high and low temperature flexibility, realizes high current-carrying and high reliability of the cable, ensures the insulating property and electrical safety of the material, and is suitable for a high-current-carrying special cable sheath.

Description

Technical Field

[0001] The invention relates to the technical field of halogen-free flame-retardant polyurethane, and in particular to a high-current-carrying special halogen-free flame-retardant and tracking-resistant polyurethane material and a preparation method thereof. Background Art

[0002] Currently, the service life of high-current-carrying cables is relatively short. This is because charging cables are used too frequently. After repeated dragging, pulling, bending, friction, and being affected by external environments such as sunlight, rain, and freezing day after day, charging pile cables are prone to problems such as weakened performance and cracking of the sheath.

[0003] Polyurethane (PU) is a very large class of polymers, which are widely used in many fields of the national economy due to their excellent physical and chemical properties, including surface coatings, foams, composite materials, adhesives, etc. PU is well known for its excellent hardness, wear resistance, and low water absorption, which makes it widely used in many industries such as furniture, automobiles, and construction. Thermoplastic polyurethane elastomer, also known as thermoplastic polyurethane rubber, referred to as TPU, is a (AB)n-type block linear polymer, A is a high molecular weight (1000-6000) polyester or polyether, B is a diol containing 2-12 straight-chain carbon atoms, and the chemical structure between the AB segments is diisocyanate. The outstanding characteristics of polyurethane thermoplastic elastomers are excellent wear resistance, excellent ozone resistance, high hardness, high strength, good elasticity, low temperature resistance, and good oil resistance, chemical resistance and environmental resistance. Although thermoplastic polyurethane elastomers have many advantages, their flammability is still a problem that needs to be solved. The oxygen index of thermoplastic polyurethane elastomer without any flame retardant is only 16.5-19, which means that it is very easy to continue burning when burning. Moreover, it will emit a lot of thick smoke and toxic gases, such as carbon monoxide and hydrogen cyanide, which will not only reduce the visibility at the fire scene, but also cause serious harm to the human body and even endanger life. Therefore, polyurethane materials are limited in applications such as cable sheaths that require high flame retardancy.

[0004] The tracking resistance of polyurethane materials is relatively poor, which limits their application in cable sheath materials. Specifically, polyurethane is prone to carbonization of conductive paths under high voltage and complex environmental conditions, which leads to tracking. The root of this problem is that under certain conditions, such as when there is moisture, dirt on the surface and a high electric field strength, a conductive path will form on the surface of the polyurethane material. This process usually starts with local discharge on the surface of the material. Over time, the heat generated by the discharge will cause local carbonization of the material surface, forming a carbonized conductive path. Due to the high conductivity of the carbonized product, the electric field density will be concentrated in these carbonized parts, triggering more discharges, further expanding the carbonized area, and ultimately causing a conductive trace to form on the surface of the material, which in turn causes a short circuit. Summary of the invention

[0005] In order to overcome the shortcomings and deficiencies in the prior art, one of the objects of the present invention is to provide a halogen-free flame retardant and tracking resistant polyurethane material. The present invention adopts thermoplastic polyurethane elastomer, phosphorus-based flame retardant, layered nano zirconium phosphate, tracking resistant agent, toughening agent, flame retardant adjuvant and surface modifier to effectively overcome the inherent defects of existing charging pile cables such as weather resistance, fatigue resistance, etc. and improve the tracking resistance, flame retardancy and high and low temperature flexibility, so as to achieve high current carrying and high reliability of the cable, and develop a high current carrying and high reliability cable for charging pile cables.

[0006] The second purpose of the present invention is to provide a method for preparing a halogen-free flame retardant and tracking-resistant polyurethane material, so as to prepare a halogen-free flame retardant and tracking-resistant polyurethane material having excellent flame retardant properties, tracking-resistant properties, good compatibility with the matrix and free radical quenching function. The preparation method is simple to operate, convenient to control, high in production efficiency, low in production cost, and can be used for large-scale production.

[0007] One of the purposes of the present invention is achieved through the following technical scheme: a halogen-free flame retardant and tracking resistant polyurethane material, comprising the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 10-15 parts of phosphorus-based flame retardant, 3-5 parts of layered nano zirconium phosphate, 3-5 parts of tracking resistant additive, 5-15 parts of toughening agent, 2-4 parts of flame retardant auxiliary agent and 2-4 parts of surface modifier.

[0008] The halogen-free flame-retardant and tracking-resistant polyurethane material uses thermoplastic polyurethane elastomer as a main raw material, and the added phosphorus-based flame retardant, layered nano zirconium phosphate, tracking-resistant auxiliary agent and flame retardant auxiliary agent cooperate to achieve flame retardancy. At high temperature, the special hindered amine group of the flame retardant auxiliary agent degrades to produce aminooxy free radicals, which can inhibit the chain degradation reaction of TPU through free radical quenching. The phosphorus-based flame retardant degrades to produce phosphoric acid and cooperates with the layered nano zirconium phosphate to catalyze the carbonization reaction of the degradation product of TPU. The carbonization product, the layered nano zirconium phosphate and the tracking-resistant auxiliary agent jointly construct a layered porous carbon layer. The closed space provided by the porous carbon layer can further promote free radical quenching and catalytic carbonization. Therefore, the free radical quenching and the carbon layer barrier effect cooperate to play a high-efficiency flame retardant effect. The added tracking-resistant auxiliary agent has excellent electrical insulation performance. The insulating property enables the anti-tracking agent to effectively prevent the leakage of charge under high voltage and complex environment, thereby reducing the risk of leakage tracking. The dielectric constant of the anti-tracking agent is low, which means that under the action of the electric field, the polarization effect inside the material is small, and the charge is not easy to accumulate inside the material, thereby reducing the formation of electric tracks. The anti-tracking agent can promote the ceramicization of the material at high temperature to form a dense ceramic layer. This ceramic layer can effectively block the bombardment of the arc and prevent the generation and development of electric tracks, thereby significantly improving the material's anti-tracking performance; combined with toughening agents and surface modifiers, the halogen-free flame retardant and anti-tracking polyurethane material as a whole can effectively overcome the inherent defects of existing charging pile cables such as weather resistance, fatigue resistance, etc., and improve the anti-tracking agent, flame retardancy and high and low temperature flexibility, so as to achieve high current carrying and high reliability of the cable.

[0009] Preferably, the flame retardant auxiliary agent is a siloxane containing a hindered amine structure.

[0010] Preferably, the preparation method of each portion of the hindered amine structure-containing siloxane comprises the following steps:

[0011] (R1), add 180-200 parts of organic solvent and 15-20 parts of cyanuric chloride into the reaction kettle at a temperature of 0-25°C, and stir evenly;

[0012] (R2), dissolving 20-25 parts of alkoxysilane and 0.05-0.1 parts of hindered amine monomer in 7-10 parts of organic solvent respectively, and slowly adding them into the reaction kettle within 1-4 hours, and at the same time, dropping 18-25 parts of acid binding agent-water solution into the reaction kettle, and continuing the reaction for 1-6 hours after the dropwise addition is completed;

[0013] (R3), heating to 45-65°C, slowly dropping 25-35 parts of a mixed aqueous solution of a diamine monomer and an acid binding agent into the reaction kettle within 1-3 hours, and continuing the reaction for 1-6 hours after the dropwise addition is completed to obtain a reaction solution;

[0014] (R4), filtering, washing and vacuum drying the reaction solution to obtain a siloxane containing a hindered amine structure.

[0015] Preferably, the organic solvent is one or more of acetone, cyclohexanone, butanone, toluene, and ethyl acetate; the alkoxysilane is one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and γ-aminopropylmethyldiethoxysilane; the hindered amine monomer is one or more of 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine, 4-hydroxy-2,2,6,6-tetramethyl-1-(1-phenylethoxy)piperidine, and tetramethylpiperidinamine.

[0016] The structural formula of the 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine is as follows:

[0017]

[0018] The structural formula of the 4-hydroxy-2,2,6,6-tetramethyl-1-(1-phenylethoxy)piperidine is as follows:

[0019]

[0020] The structural formula of the tetramethylpiperidinamine is as follows:

[0021]

[0022] Preferably, the concentration of the acid-binding agent-water solution is 3-8 mol / L; the concentration of the mixed aqueous solution of the diamine monomer and the acid-binding agent is 10-30wt%, and the mass ratio of the diamine monomer to the acid-binding agent in the mixed aqueous solution of the diamine monomer and the acid-binding agent is 2-4:3-5; the acid-binding agent is one or more of sodium hydroxide, sodium acetate, sodium carbonate, and triethylamine; and the diamine monomer is one or more of ethylenediamine, tetramethyldiamine, butanediamine, and p-phenylenediamine.

[0023] Preferably, the phosphorus-based flame retardant is one or more of polyaryl phosphate, ammonium polyphosphate, organic phosphinate, tris(β-chloroethyl) phosphate, and dimethyl methylphosphonate.

[0024] By adopting the above technical scheme, the preferred polyaryl phosphate will degrade under heat to produce phosphoric acid when flame retardant at high temperature and cooperate with solid acid to catalyze the carbonization reaction of the degradation products of TPU. The carbonized products are jointly constructed with the layered nano zirconium phosphate material and fluorphlogopite to form a layered porous carbon layer; the closed space provided by the layered porous carbon layer can in turn further promote free radical quenching and catalytic carbonization.

[0025] Preferably, the anti-tracking agent is one or more of talc, hydrotalcite, and fluorphlogopite.

[0026] By adopting the above technical solution, the preferred fluorphlogopite has excellent electrical insulation performance, and its volume resistivity is 1000 times higher than that of natural mica under high temperature conditions. This high insulation performance enables fluorphlogopite to effectively prevent the leakage of charge under high voltage and complex environment, thereby reducing the risk of leakage tracking. The dielectric constant of fluorphlogopite is low, which means that under the action of the electric field, the polarization effect inside the material is small, and the charge is not easy to accumulate inside the material, thereby reducing the formation of electric tracks. Fluorphlogopite can promote the ceramicization of the material at high temperature to form a dense ceramic layer, which can effectively block the bombardment of the arc and prevent the generation and development of electric tracks, thereby significantly improving the material's resistance to leakage tracking.

[0027] Preferably, the surface modifier is one or more of 3-aminopropyltriethoxysilane and 3-methacryloxypropyltrimethoxysilane.

[0028] Preferably, the toughening agent is one or more of maleic anhydride grafted polypropylene elastomer, methyl methacrylate-butadiene-styrene, liquid acrylic rubber, and liquid polybutadiene rubber.

[0029] By adopting the above technical scheme, the preferred maleic anhydride grafted polypropylene elastomer enhances the interaction between the maleic anhydride and the polar material by introducing maleic anhydride functional groups into the polypropylene molecular chain, thereby improving the toughness of the material; it can also become a bridge to enhance the adhesion and compatibility between polar materials and non-polar materials, and can greatly improve the affinity and dispersibility of layered nano zirconium phosphate and anti-tracking additive in polyurethane materials.

[0030] The second object of the present invention is achieved by the following technical solution: The preparation method of the above-mentioned halogen-free flame retardant and tracking resistant polyurethane material comprises the following steps:

[0031] (S1), taking thermoplastic polyurethane elastomer, phosphorus-based flame retardant, layered nano zirconium phosphate, anti-tracking agent, toughening agent, flame retardant auxiliary agent and surface modifier according to weight parts, and setting aside;

[0032] (S2), mixing a thermoplastic polyurethane elastomer, a phosphorus-based flame retardant, a layered nano zirconium phosphate, an anti-tracking agent, a toughening agent, a flame retardant aid and a surface modifier in a high-speed mixer to obtain a mixture;

[0033] (S3), adding the mixture into a twin-screw extruder for melt extrusion and granulation to obtain a halogen-free, flame-retardant and tracking-resistant polyurethane material.

[0034] Among them, the processing temperatures of each section of the twin-screw extruder starting from the feeding section are: 165-175℃, 170-180℃, 175-185℃, 175-185℃, 180-190℃, 180-190℃, 175-185℃, 175-185℃, 170-180℃, the head temperature is 175-185℃, and the screw speed is 200-400r / min.

[0035] The beneficial effects of the present invention are:

[0036] 1. When facing the severe challenge of dangerous high temperature or open flame, the hindered amine siloxane of the halogen-free flame-retardant and tracking-resistant polyurethane material of the present invention is thermally degraded first. This degradation process is not a simple destruction, but produces a series of degradation products with efficient free radical quenching effect. These degradation products play a vital role in the combustion process of the material. They can effectively inhibit the free radical chain thermal degradation of the TPU matrix, thereby delaying or even preventing the spread of combustion. At the same time, the flame retardant adjuvant will also synergize with the TPU matrix to efficiently carbonize on the surface of the layered nano zirconium phosphate and the tracking-resistant adjuvant to form a dense and stable barrier layer. This barrier layer can not only block the further transfer of heat, but also prevent oxygen from contacting combustible substances, further exerting an efficient flame retardant effect.

[0037] 2. The free radical quenching properties of the special hindered amine group of the flame retardant adjuvant not only excel in flame retardancy, but also give TPU excellent resistance to UV and thermal oxidation aging. Under long-term exposure to ultraviolet rays, the material is prone to photodegradation, resulting in performance degradation. However, the presence of hindered amine groups can effectively absorb and quench free radicals induced by ultraviolet rays, thereby protecting the TPU matrix from damage by ultraviolet rays and extending the service life of the material. In addition, in a thermal oxygen environment, the material is also facing the risk of aging. The hindered amine group slows down the oxidation process of the material by capturing free radicals generated by thermal oxygen, further improving the thermal oxidation stability of TPU.

[0038] 3. Fluorphlogopite, as a special material, has a high fluorine content. Its fluorine atoms not only show extremely high stability in chemical properties, but also have excellent charge dissipation effect. In high-voltage and high-current application scenarios, TPU insulating materials are faced with the risk of damage from leakage tracking, and the addition of fluorphlogopite can effectively reduce this risk. When the material is in a high electric field environment, fluorine atoms can quickly dissipate the accumulated charge and prevent the charge from gathering on the surface of the material to form a high electric field strength area, thereby avoiding the occurrence of leakage tracking and ensuring the insulation performance and electrical safety of the material.

[0039] The preparation method of the halogen-free flame-retardant and tracking-resistant polyurethane material of the present invention has the advantages of simple operation, convenient control, high production efficiency and low production cost, and can be used for large-scale production. DETAILED DESCRIPTION

[0040] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with embodiments, and the contents mentioned in the implementation modes are not intended to limit the present invention.

[0041] Example 1

[0042] A halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 10 parts of phosphorus-based flame retardant, 3 parts of layered nano zirconium phosphate, 5 parts of tracking-resistant auxiliary agent, 10 parts of toughening agent, 2 parts of flame retardant auxiliary agent and 2 parts of surface modifier.

[0043] The flame retardant auxiliary agent is a siloxane containing a hindered amine structure.

[0044] The preparation method of each portion of the hindered amine structure-containing siloxane comprises the following steps:

[0045] (R1), add 190 parts of organic solvent and 18.8 parts of cyanuric chloride into the reaction kettle at 0°C by weight and stir evenly;

[0046] (R2), 22.3 parts of alkoxysilane and 0.076 parts of hindered amine monomer were dissolved in 7.88 parts of organic solvent respectively, and slowly added into the reaction kettle within 1 hour, and 20 parts of acid binding agent-water solution were added dropwise into the reaction kettle at the same time, and the reaction was continued for 3 hours after the addition was completed;

[0047] (R3), heating to 45°C, slowly dropping 27.1 parts of a mixed aqueous solution of a diamine monomer and an acid binding agent into the reaction kettle within 1 hour, and continuing the reaction for 3 hours after the dropwise addition to obtain a reaction solution;

[0048] (R4), filtering the reaction solution, washing the filter cake with deionized water and acetone, and vacuum drying to obtain a siloxane containing a hindered amine structure.

[0049] The organic solvent is acetone; the alkoxysilane is 3-aminopropyltriethoxysilane; and the hindered amine monomer is 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine.

[0050] The concentration of the acid-binding agent-water solution is 5 mol / L; the concentration of the mixed aqueous solution of the diamine monomer and the acid-binding agent is 25 wt %, and the mass ratio of the diamine monomer to the acid-binding agent in the mixed aqueous solution of the diamine monomer and the acid-binding agent is 3.1:4; the acid-binding agent is sodium hydroxide; and the diamine monomer is ethylenediamine.

[0051] The phosphorus-based flame retardant is polyaryl phosphate.

[0052] The anti-tracking additive is fluorphlogopite.

[0053] The surface modifier is 3-aminopropyltriethoxysilane.

[0054] The toughening agent is maleic anhydride grafted polypropylene elastomer.

[0055] The preparation method of the halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following steps:

[0056] (S1), taking thermoplastic polyurethane elastomer, phosphorus-based flame retardant, layered nano zirconium phosphate, anti-tracking agent, toughening agent, flame retardant auxiliary agent and surface modifier according to weight parts, and setting aside;

[0057] (S2), mixing a thermoplastic polyurethane elastomer, a phosphorus-based flame retardant, a layered nano zirconium phosphate, an anti-tracking agent, a toughening agent, a flame retardant aid and a surface modifier in a high-speed mixer to obtain a mixture;

[0058] (S3), adding the mixture into a twin-screw extruder for melt extrusion and granulation to obtain a halogen-free, flame-retardant and tracking-resistant polyurethane material.

[0059] The temperatures in each zone of the twin-screw extruder are 170°C, 175°C, 180°C, 180°C, 185°C, 185°C, 180°C, 180°C, and 175°C respectively, the head temperature is 180°C, and the screw speed is 300r / min.

[0060] Example 2

[0061] A halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 15 parts of phosphorus-based flame retardant, 3 parts of layered nano zirconium phosphate, 5 parts of tracking-resistant auxiliary agent, 10 parts of toughening agent, 2 parts of flame retardant auxiliary agent and 2 parts of surface modifier.

[0062] The flame retardant auxiliary agent is a siloxane containing a hindered amine structure.

[0063] The preparation method of each portion of the hindered amine structure-containing siloxane comprises the following steps:

[0064] (R1), add 190 parts of organic solvent and 18.8 parts of cyanuric chloride into the reaction kettle at 0°C by weight and stir evenly;

[0065] (R2), 22.3 parts of alkoxysilane and 0.076 parts of hindered amine monomer were dissolved in 7.88 parts of organic solvent respectively, and slowly added into the reaction kettle within 1 hour, and 20 parts of acid binding agent-water solution were added dropwise into the reaction kettle at the same time, and the reaction was continued for 3 hours after the addition was completed;

[0066] (R3), heating to 45°C, slowly dropping 27.1 parts of a mixed aqueous solution of a diamine monomer and an acid binding agent into the reaction kettle within 1 hour, and continuing the reaction for 3 hours after the dropwise addition to obtain a reaction solution;

[0067] (R4), filtering the reaction solution, washing the filter cake with deionized water and acetone, and vacuum drying to obtain a siloxane containing a hindered amine structure.

[0068] The organic solvent is acetone; the alkoxysilane is 3-aminopropyltriethoxysilane; and the hindered amine monomer is 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine.

[0069] The concentration of the acid-binding agent-water solution is 5 mol / L; the concentration of the mixed aqueous solution of the diamine monomer and the acid-binding agent is 25 wt %, and the mass ratio of the diamine monomer to the acid-binding agent in the mixed aqueous solution of the diamine monomer and the acid-binding agent is 3.1:4; the acid-binding agent is sodium hydroxide; and the diamine monomer is ethylenediamine.

[0070] The phosphorus-based flame retardant is polyaryl phosphate.

[0071] The anti-tracking additive is fluorphlogopite.

[0072] The surface modifier is 3-aminopropyltriethoxysilane.

[0073] The toughening agent is maleic anhydride grafted polypropylene elastomer.

[0074] The preparation method of the halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following steps:

[0075] (S1), taking thermoplastic polyurethane elastomer, phosphorus-based flame retardant, layered nano zirconium phosphate, anti-tracking agent, toughening agent, flame retardant auxiliary agent and surface modifier according to weight parts, and setting aside;

[0076] (S2), mixing a thermoplastic polyurethane elastomer, a phosphorus-based flame retardant, a layered nano zirconium phosphate, an anti-tracking agent, a toughening agent, a flame retardant aid and a surface modifier in a high-speed mixer to obtain a mixture;

[0077] (S3), adding the mixture into a twin-screw extruder for melt extrusion and granulation to obtain a halogen-free, flame-retardant and tracking-resistant polyurethane material.

[0078] The temperatures in each zone of the twin-screw extruder are 170°C, 175°C, 180°C, 180°C, 185°C, 185°C, 180°C, 180°C, and 175°C respectively, the head temperature is 180°C, and the screw speed is 300r / min.

[0079] Example 3

[0080] A halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 15 parts of phosphorus-based flame retardant, 4 parts of layered nano zirconium phosphate, 3 parts of tracking-resistant auxiliary agent, 5 parts of toughening agent, 2 parts of flame retardant auxiliary agent and 2 parts of surface modifier.

[0081] The flame retardant auxiliary agent is a siloxane containing a hindered amine structure.

[0082] The preparation method of each portion of the hindered amine structure-containing siloxane comprises the following steps:

[0083] (R1), add 190 parts of organic solvent and 18.8 parts of cyanuric chloride into the reaction kettle at 0°C by weight and stir evenly;

[0084] (R2), 22.3 parts of alkoxysilane and 0.076 parts of hindered amine monomer were dissolved in 7.88 parts of organic solvent respectively, and slowly added into the reaction kettle within 1 hour, and 20 parts of acid binding agent-water solution were added dropwise into the reaction kettle at the same time, and the reaction was continued for 3 hours after the addition was completed;

[0085] (R3), heating to 45°C, slowly dropping 27.1 parts of a mixed aqueous solution of a diamine monomer and an acid binding agent into the reaction kettle within 1 hour, and continuing the reaction for 3 hours after the dropwise addition to obtain a reaction solution;

[0086] (R4), filtering the reaction solution, washing the filter cake with deionized water and acetone, and vacuum drying to obtain a siloxane containing a hindered amine structure.

[0087] The organic solvent is acetone; the alkoxysilane is 3-aminopropyltriethoxysilane; and the hindered amine monomer is 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine.

[0088] The concentration of the acid-binding agent-water solution is 5 mol / L; the concentration of the mixed aqueous solution of the diamine monomer and the acid-binding agent is 25 wt %, and the mass ratio of the diamine monomer to the acid-binding agent in the mixed aqueous solution of the diamine monomer and the acid-binding agent is 3.1:4; the acid-binding agent is sodium hydroxide; and the diamine monomer is ethylenediamine.

[0089] The phosphorus-based flame retardant is polyaryl phosphate.

[0090] The anti-tracking additive is fluorphlogopite.

[0091] The surface modifier is 3-aminopropyltriethoxysilane.

[0092] The toughening agent is maleic anhydride grafted polypropylene elastomer.

[0093] The preparation method of the halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following steps:

[0094] (S1), taking thermoplastic polyurethane elastomer, phosphorus-based flame retardant, layered nano zirconium phosphate, anti-tracking agent, toughening agent, flame retardant auxiliary agent and surface modifier according to weight parts, and setting aside;

[0095] (S2), mixing a thermoplastic polyurethane elastomer, a phosphorus-based flame retardant, a layered nano zirconium phosphate, an anti-tracking agent, a toughening agent, a flame retardant aid and a surface modifier in a high-speed mixer to obtain a mixture;

[0096] (S3), adding the mixture into a twin-screw extruder for melt extrusion and granulation to obtain a halogen-free, flame-retardant and tracking-resistant polyurethane material.

[0097] The temperatures in each zone of the twin-screw extruder are 170°C, 175°C, 180°C, 180°C, 185°C, 185°C, 180°C, 180°C, and 175°C respectively, the head temperature is 180°C, and the screw speed is 300r / min.

[0098] Example 4

[0099] A halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 15 parts of phosphorus-based flame retardant, 4 parts of layered nano zirconium phosphate, 3 parts of tracking-resistant auxiliary agent, 5 parts of toughening agent, 4 parts of flame retardant auxiliary agent and 2 parts of surface modifier.

[0100] The flame retardant auxiliary agent is a siloxane containing a hindered amine structure.

[0101] The preparation method of each portion of the hindered amine structure-containing siloxane comprises the following steps:

[0102] (R1), add 190 parts of organic solvent and 18.8 parts of cyanuric chloride into the reaction kettle at 0°C by weight and stir evenly;

[0103] (R2), 22.3 parts of alkoxysilane and 0.076 parts of hindered amine monomer were dissolved in 7.88 parts of organic solvent respectively, and slowly added into the reaction kettle within 1 hour, and 20 parts of acid binding agent-water solution were added dropwise into the reaction kettle at the same time, and the reaction was continued for 3 hours after the addition was completed;

[0104] (R3), heating to 45°C, slowly dropping 27.1 parts of a mixed aqueous solution of a diamine monomer and an acid binding agent into the reaction kettle within 1 hour, and continuing the reaction for 3 hours after the dropwise addition to obtain a reaction solution;

[0105] (R4), filtering the reaction solution, washing the filter cake with deionized water and acetone, and vacuum drying to obtain a siloxane containing a hindered amine structure.

[0106] The organic solvent is acetone; the alkoxysilane is 3-aminopropyltriethoxysilane; and the hindered amine monomer is 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine.

[0107] The concentration of the acid-binding agent-water solution is 5 mol / L; the concentration of the mixed aqueous solution of the diamine monomer and the acid-binding agent is 25 wt %, and the mass ratio of the diamine monomer to the acid-binding agent in the mixed aqueous solution of the diamine monomer and the acid-binding agent is 3.1:4; the acid-binding agent is sodium hydroxide; and the diamine monomer is ethylenediamine.

[0108] The phosphorus-based flame retardant is polyaryl phosphate.

[0109] The anti-tracking additive is fluorphlogopite.

[0110] The surface modifier is 3-aminopropyltriethoxysilane.

[0111] The toughening agent is maleic anhydride grafted polypropylene elastomer.

[0112] The preparation method of the halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following steps:

[0113] (S1), taking thermoplastic polyurethane elastomer, phosphorus-based flame retardant, layered nano zirconium phosphate, anti-tracking agent, toughening agent, flame retardant auxiliary agent and surface modifier according to weight parts, and setting aside;

[0114] (S2), mixing a thermoplastic polyurethane elastomer, a phosphorus-based flame retardant, a layered nano zirconium phosphate, an anti-tracking agent, a toughening agent, a flame retardant aid and a surface modifier in a high-speed mixer to obtain a mixture;

[0115] (S3), adding the mixture into a twin-screw extruder for melt extrusion and granulation to obtain a halogen-free, flame-retardant and tracking-resistant polyurethane material.

[0116] The temperatures in each zone of the twin-screw extruder are 170°C, 175°C, 180°C, 180°C, 185°C, 185°C, 180°C, 180°C, and 175°C respectively, the head temperature is 180°C, and the screw speed is 300r / min.

[0117] Example 5

[0118] A halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 10 parts of phosphorus-based flame retardant, 5 parts of layered nano zirconium phosphate, 5 parts of tracking-resistant auxiliary agent, 10 parts of toughening agent, 2 parts of flame retardant auxiliary agent and 2 parts of surface modifier.

[0119] The flame retardant auxiliary agent is a siloxane containing a hindered amine structure.

[0120] The preparation method of each portion of the hindered amine structure-containing siloxane comprises the following steps:

[0121] (R1), add 190 parts of organic solvent and 18.8 parts of cyanuric chloride into the reaction kettle at 0°C by weight and stir evenly;

[0122] (R2), 22.3 parts of alkoxysilane and 0.076 parts of hindered amine monomer were dissolved in 7.88 parts of organic solvent respectively, and slowly added into the reaction kettle within 1 hour, and 20 parts of acid binding agent-water solution were added dropwise into the reaction kettle at the same time, and the reaction was continued for 3 hours after the addition was completed;

[0123] (R3), heating to 45°C, slowly dropping 27.1 parts of a mixed aqueous solution of a diamine monomer and an acid binding agent into the reaction kettle within 1 hour, and continuing the reaction for 3 hours after the dropwise addition to obtain a reaction solution;

[0124] (R4), filtering the reaction solution, washing the filter cake with deionized water and acetone, and vacuum drying to obtain a siloxane containing a hindered amine structure.

[0125] The organic solvent is acetone; the alkoxysilane is 3-aminopropyltriethoxysilane; and the hindered amine monomer is 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine.

[0126] The concentration of the acid-binding agent-water solution is 5 mol / L; the concentration of the mixed aqueous solution of the diamine monomer and the acid-binding agent is 25 wt %, and the mass ratio of the diamine monomer to the acid-binding agent in the mixed aqueous solution of the diamine monomer and the acid-binding agent is 3.1:4; the acid-binding agent is sodium hydroxide; and the diamine monomer is ethylenediamine.

[0127] The phosphorus-based flame retardant is polyaryl phosphate.

[0128] The anti-tracking additive is fluorphlogopite.

[0129] The surface modifier is 3-aminopropyltriethoxysilane.

[0130] The toughening agent is maleic anhydride grafted polypropylene elastomer.

[0131] The preparation method of the halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following steps:

[0132] (S1), taking thermoplastic polyurethane elastomer, phosphorus-based flame retardant, layered nano zirconium phosphate, anti-tracking agent, toughening agent, flame retardant auxiliary agent and surface modifier according to weight parts, and setting aside;

[0133] (S2), mixing a thermoplastic polyurethane elastomer, a phosphorus-based flame retardant, a layered nano zirconium phosphate, an anti-tracking agent, a toughening agent, a flame retardant aid and a surface modifier in a high-speed mixer to obtain a mixture;

[0134] (S3), adding the mixture into a twin-screw extruder for melt extrusion and granulation to obtain a halogen-free, flame-retardant and tracking-resistant polyurethane material.

[0135] The temperatures in each zone of the twin-screw extruder are 170°C, 175°C, 180°C, 180°C, 185°C, 185°C, 180°C, 180°C, and 175°C respectively, the head temperature is 180°C, and the screw speed is 300r / min.

[0136] Example 6

[0137] A halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 10 parts of phosphorus-based flame retardant, 3 parts of layered nano zirconium phosphate, 3 parts of tracking-resistant auxiliary agent, 10 parts of toughening agent, 2 parts of flame retardant auxiliary agent and 2 parts of surface modifier.

[0138] The flame retardant auxiliary agent is a siloxane containing a hindered amine structure.

[0139] The preparation method of each portion of the hindered amine structure-containing siloxane comprises the following steps:

[0140] (R1), add 190 parts of organic solvent and 18.8 parts of cyanuric chloride into the reaction kettle at 0°C by weight and stir evenly;

[0141] (R2), 22.3 parts of alkoxysilane and 0.076 parts of hindered amine monomer were dissolved in 7.88 parts of organic solvent respectively, and slowly added into the reaction kettle within 1 hour, and 20 parts of acid binding agent-water solution were added dropwise into the reaction kettle at the same time, and the reaction was continued for 3 hours after the addition was completed;

[0142] (R3), heating to 45°C, slowly dropping 27.1 parts of a mixed aqueous solution of a diamine monomer and an acid binding agent into the reaction kettle within 1 hour, and continuing the reaction for 3 hours after the dropwise addition to obtain a reaction solution;

[0143] (R4), filtering the reaction solution, washing the filter cake with deionized water and acetone, and vacuum drying to obtain a siloxane containing a hindered amine structure.

[0144] The organic solvent is acetone; the alkoxysilane is 3-aminopropyltriethoxysilane; and the hindered amine monomer is 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine.

[0145] The concentration of the acid-binding agent-water solution is 5 mol / L; the concentration of the mixed aqueous solution of the diamine monomer and the acid-binding agent is 25 wt %, and the mass ratio of the diamine monomer to the acid-binding agent in the mixed aqueous solution of the diamine monomer and the acid-binding agent is 3.1:4; the acid-binding agent is sodium hydroxide; and the diamine monomer is ethylenediamine.

[0146] The phosphorus-based flame retardant is polyaryl phosphate.

[0147] The anti-tracking additive is fluorphlogopite.

[0148] The surface modifier is 3-aminopropyltriethoxysilane.

[0149] The toughening agent is maleic anhydride grafted polypropylene elastomer.

[0150] The preparation method of the halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following steps:

[0151] (S1), taking thermoplastic polyurethane elastomer, phosphorus-based flame retardant, layered nano zirconium phosphate, anti-tracking agent, toughening agent, flame retardant auxiliary agent and surface modifier according to weight parts, and setting aside;

[0152] (S2), mixing a thermoplastic polyurethane elastomer, a phosphorus-based flame retardant, a layered nano zirconium phosphate, an anti-tracking agent, a toughening agent, a flame retardant aid and a surface modifier in a high-speed mixer to obtain a mixture;

[0153] (S3), adding the mixture into a twin-screw extruder for melt extrusion and granulation to obtain a halogen-free, flame-retardant and tracking-resistant polyurethane material.

[0154] The temperatures in each zone of the twin-screw extruder are 170°C, 175°C, 180°C, 180°C, 185°C, 185°C, 180°C, 180°C, and 175°C respectively, the head temperature is 180°C, and the screw speed is 300r / min.

[0155] Example 7

[0156] A halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 15 parts of phosphorus-based flame retardant, 3 parts of layered nano zirconium phosphate, 3 parts of tracking-resistant auxiliary agent, 5 parts of toughening agent, 2 parts of flame retardant auxiliary agent and 2 parts of surface modifier.

[0157] The flame retardant auxiliary agent is a siloxane containing a hindered amine structure.

[0158] The preparation method of each portion of the hindered amine structure-containing siloxane comprises the following steps:

[0159] (R1), add 190 parts of organic solvent and 18.8 parts of cyanuric chloride into the reaction kettle at 0°C by weight and stir evenly;

[0160] (R2), 22.3 parts of alkoxysilane and 0.076 parts of hindered amine monomer were dissolved in 7.88 parts of organic solvent respectively, and slowly added into the reaction kettle within 1 hour, and 20 parts of acid binding agent-water solution were added dropwise into the reaction kettle at the same time, and the reaction was continued for 3 hours after the addition was completed;

[0161] (R3), heating to 45°C, slowly dropping 27.1 parts of a mixed aqueous solution of a diamine monomer and an acid binding agent into the reaction kettle within 1 hour, and continuing the reaction for 3 hours after the dropwise addition to obtain a reaction solution;

[0162] (R4), filtering the reaction solution, washing the filter cake with deionized water and acetone, and vacuum drying to obtain a siloxane containing a hindered amine structure.

[0163] The organic solvent is acetone; the alkoxysilane is 3-aminopropyltriethoxysilane; and the hindered amine monomer is 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine.

[0164] The concentration of the acid-binding agent-water solution is 5 mol / L; the concentration of the mixed aqueous solution of the diamine monomer and the acid-binding agent is 25 wt %, and the mass ratio of the diamine monomer to the acid-binding agent in the mixed aqueous solution of the diamine monomer and the acid-binding agent is 3.1:4; the acid-binding agent is sodium hydroxide; and the diamine monomer is ethylenediamine.

[0165] The phosphorus-based flame retardant is polyaryl phosphate.

[0166] The anti-tracking additive is fluorphlogopite.

[0167] The surface modifier is 3-aminopropyltriethoxysilane.

[0168] The toughening agent is maleic anhydride grafted polypropylene elastomer.

[0169] The preparation method of the halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following steps:

[0170] (S1), taking thermoplastic polyurethane elastomer, phosphorus-based flame retardant, layered nano zirconium phosphate, anti-tracking agent, toughening agent, flame retardant auxiliary agent and surface modifier according to weight parts, and setting aside;

[0171] (S2), mixing a thermoplastic polyurethane elastomer, a phosphorus-based flame retardant, a layered nano zirconium phosphate, an anti-tracking agent, a toughening agent, a flame retardant aid and a surface modifier in a high-speed mixer to obtain a mixture;

[0172] (S3), adding the mixture into a twin-screw extruder for melt extrusion and granulation to obtain a halogen-free, flame-retardant and tracking-resistant polyurethane material.

[0173] The temperatures in each zone of the twin-screw extruder are 170°C, 175°C, 180°C, 180°C, 185°C, 185°C, 180°C, 180°C, and 175°C respectively, the head temperature is 180°C, and the screw speed is 300r / min.

[0174] Example 8

[0175] A halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 15 parts of phosphorus-based flame retardant, 5 parts of layered nano zirconium phosphate, 3 parts of tracking-resistant additive, 5 parts of toughening agent, 2 parts of flame retardant auxiliary agent and 2 parts of surface modifier.

[0176] The flame retardant auxiliary agent is a siloxane containing a hindered amine structure.

[0177] The preparation method of each portion of the hindered amine structure-containing siloxane comprises the following steps:

[0178] (R1), add 190 parts of organic solvent and 18.8 parts of cyanuric chloride into the reaction kettle at 0°C by weight and stir evenly;

[0179] (R2), 22.3 parts of alkoxysilane and 0.076 parts of hindered amine monomer were dissolved in 7.88 parts of organic solvent respectively, and slowly added into the reaction kettle within 1 hour, and 20 parts of acid binding agent-water solution were added dropwise into the reaction kettle at the same time, and the reaction was continued for 3 hours after the addition was completed;

[0180] (R3), heating to 45°C, slowly dropping 27.1 parts of a mixed aqueous solution of a diamine monomer and an acid binding agent into the reaction kettle within 1 hour, and continuing the reaction for 3 hours after the dropwise addition to obtain a reaction solution;

[0181] (R4), filtering the reaction solution, washing the filter cake with deionized water and acetone, and vacuum drying to obtain a siloxane containing a hindered amine structure.

[0182] The organic solvent is acetone; the alkoxysilane is 3-aminopropyltriethoxysilane; and the hindered amine monomer is 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine.

[0183] The concentration of the acid-binding agent-water solution is 5 mol / L; the concentration of the mixed aqueous solution of the diamine monomer and the acid-binding agent is 25 wt %, and the mass ratio of the diamine monomer to the acid-binding agent in the mixed aqueous solution of the diamine monomer and the acid-binding agent is 3.1:4; the acid-binding agent is sodium hydroxide; and the diamine monomer is ethylenediamine.

[0184] The phosphorus-based flame retardant is polyaryl phosphate.

[0185] The anti-tracking additive is fluorphlogopite.

[0186] The surface modifier is 3-aminopropyltriethoxysilane.

[0187] The toughening agent is maleic anhydride grafted polypropylene elastomer.

[0188] The preparation method of the halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following steps:

[0189] (S1), taking thermoplastic polyurethane elastomer, phosphorus-based flame retardant, layered nano zirconium phosphate, anti-tracking agent, toughening agent, flame retardant auxiliary agent and surface modifier according to weight parts, and setting aside;

[0190] (S2), mixing a thermoplastic polyurethane elastomer, a phosphorus-based flame retardant, a layered nano zirconium phosphate, an anti-tracking agent, a toughening agent, a flame retardant aid and a surface modifier in a high-speed mixer to obtain a mixture;

[0191] (S3), adding the mixture into a twin-screw extruder for melt extrusion and granulation to obtain a halogen-free, flame-retardant and tracking-resistant polyurethane material.

[0192] The temperatures in each zone of the twin-screw extruder are 170°C, 175°C, 180°C, 180°C, 185°C, 185°C, 180°C, 180°C, and 175°C respectively, the head temperature is 180°C, and the screw speed is 300r / min.

[0193] Example 9

[0194] A halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 10 parts of phosphorus-based flame retardant, 5 parts of layered nano zirconium phosphate, 3 parts of tracking-resistant auxiliary agent, 15 parts of toughening agent, 2 parts of flame retardant auxiliary agent and 2 parts of surface modifier.

[0195] The flame retardant auxiliary agent is a siloxane containing a hindered amine structure.

[0196] The preparation method of each portion of the hindered amine structure-containing siloxane comprises the following steps:

[0197] (R1), add 190 parts of organic solvent and 18.8 parts of cyanuric chloride into the reaction kettle at 0°C by weight and stir evenly;

[0198] (R2), 22.3 parts of alkoxysilane and 0.076 parts of hindered amine monomer were dissolved in 7.88 parts of organic solvent respectively, and slowly added into the reaction kettle within 1 hour, and 20 parts of acid binding agent-water solution were added dropwise into the reaction kettle at the same time, and the reaction was continued for 3 hours after the addition was completed;

[0199] (R3), heating to 45°C, slowly dropping 27.1 parts of a mixed aqueous solution of a diamine monomer and an acid binding agent into the reaction kettle within 1 hour, and continuing the reaction for 3 hours after the dropwise addition to obtain a reaction solution;

[0200] (R4), filtering the reaction solution, washing the filter cake with deionized water and acetone, and vacuum drying to obtain a siloxane containing a hindered amine structure.

[0201] The organic solvent is acetone; the alkoxysilane is 3-aminopropyltriethoxysilane; and the hindered amine monomer is 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine.

[0202] The concentration of the acid-binding agent-water solution is 5 mol / L; the concentration of the mixed aqueous solution of the diamine monomer and the acid-binding agent is 25 wt %, and the mass ratio of the diamine monomer to the acid-binding agent in the mixed aqueous solution of the diamine monomer and the acid-binding agent is 3.1:4; the acid-binding agent is sodium hydroxide; and the diamine monomer is ethylenediamine.

[0203] The phosphorus-based flame retardant is polyaryl phosphate.

[0204] The anti-tracking additive is fluorphlogopite.

[0205] The surface modifier is 3-aminopropyltriethoxysilane.

[0206] The toughening agent is maleic anhydride grafted polypropylene elastomer.

[0207] The preparation method of the halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following steps:

[0208] (S1), taking thermoplastic polyurethane elastomer, phosphorus-based flame retardant, layered nano zirconium phosphate, anti-tracking agent, toughening agent, flame retardant auxiliary agent and surface modifier according to weight parts, and setting aside;

[0209] (S2), mixing a thermoplastic polyurethane elastomer, a phosphorus-based flame retardant, a layered nano zirconium phosphate, an anti-tracking agent, a toughening agent, a flame retardant aid and a surface modifier in a high-speed mixer to obtain a mixture;

[0210] (S3), adding the mixture into a twin-screw extruder for melt extrusion and granulation to obtain a halogen-free, flame-retardant and tracking-resistant polyurethane material.

[0211] The temperatures in each zone of the twin-screw extruder are 170°C, 175°C, 180°C, 180°C, 185°C, 185°C, 180°C, 180°C, and 175°C respectively, the head temperature is 180°C, and the screw speed is 300r / min.

[0212] Comparative Example 1

[0213] A polyurethane material is a thermoplastic polyurethane elastomer.

[0214] Comparative Example 2

[0215] In order to prove that the halogen-free flame-retardant and tracking-resistant polyurethane material prepared by the present invention can significantly improve the flame retardant efficiency and have excellent tracking-resistant performance compared with the traditional flame-retardant polyurethane material, the flame retardant is di(2-di-tert-butylterephthalate)carboxylate (DMMP) and the tracking-resistant auxiliary agent is zinc oxide as a comparison.

[0216] The preparation method of the flame retardant polyurethane material comprises the following steps: adding 68.6wt% of thermoplastic polyurethane elastomer to an open rubber mixer with a double-roll temperature of 175°C, and after the thermoplastic polyurethane elastomer is melted and rolled, adding 16.66wt% of di(2-di-tert-butylterephthalate)formate (DMMP), 3wt% of zinc oxide, 2.14wt% of layered nano zirconium phosphate, 6.86wt% of maleic anhydride grafted polypropylene elastomer, 1.37wt% of hindered amine structure-containing siloxane in Example 1 and 1.37wt% of 3-aminopropyltriethoxysilane, without adding fluorphlogopite, mixing for 12min, then hot pressing for 6min in a flat plate vulcanizer at 180°C, and finally cold pressing for 8min at room temperature in a cold press, producing sheets, and preparing various standard samples on a universal cutting machine.

[0217] The specific types of the added layered nano zirconium phosphate, toughening agent, flame retardant aid and surface modifier are the same as those in Example 1.

[0218] Comparative Example 3

[0219] The difference between this comparative example and Example 1 is:

[0220] A halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 12 parts of phosphorus-based flame retardant, 3 parts of layered nano zirconium phosphate, 5 parts of tracking-resistant auxiliary agent, 10 parts of toughening agent, 0 parts of flame retardant auxiliary agent and 2 parts of surface modifier; that is, the halogen-free flame-retardant and tracking-resistant polyurethane material does not contain siloxane containing hindered amine structure.

[0221] Comparative Example 4

[0222] The difference between this comparative example and Example 1 is:

[0223] A halogen-free flame-retardant and tracking-resistant polyurethane material comprises the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 13 parts of phosphorus-based flame retardant, 0 parts of layered nano zirconium phosphate, 5 parts of tracking-resistant auxiliary agent, 10 parts of toughening agent, 2 parts of flame retardant auxiliary agent and 2 parts of surface modifier; that is, the halogen-free flame-retardant and tracking-resistant polyurethane material does not contain layered nano zirconium phosphate.

[0224] Performance Testing

[0225] The polyurethane materials of Examples 1-9 and Comparative Examples 1-4 were tested for breaking strength and breaking elongation, limiting oxygen index, flame retardancy, and tracking resistance. The test methods are as follows:

[0226] Fracture strength and elongation at break: refer to GB / T 1040.3-2006, test the fracture strength and elongation at break of the material, cut the material into strip specimens with a width of 10mm and a length of 120mm, and test them under the constant elongation stretching mode; the specimen clamping length is 100mm, and the stretching speed is 20mm / min.

[0227] Limiting Oxygen Index (LOI): The test was performed in accordance with ASTM D2863 standard, and the sample size was 120mm×6.5mm×3mm.

[0228] Flame retardant grade: According to the vertical burning (UL-94) test, the sample size is 127mm×12.7mm×3.2mm.

[0229] Tracking resistance test: Voltage is applied between platinum electrodes of specified size (2mm×2mm), starting from 100V, increasing by 25V each step, up to 600V. A specified volume of conductive liquid (0.1% NH4CL) is dripped at a fixed time (60 seconds) (35mm height), and its relative tracking index is tested.

[0230] The test results are shown in Table 1 below:

[0231]

[0232] From the data in Table 1, by comparing the data of Examples 1-9 with that of Comparative Example 1, it can be seen that the halogen-free flame retardant and tracking resistant polyurethane material prepared by the present invention has excellent flame retardant properties and tracking resistant properties compared to the polyurethane elastomer without any additives.

[0233] By comparing Comparative Example 3 and Example 1, it can be seen that the absence of the addition of siloxane containing a hindered amine structure has a relatively large effect on the halogen-free flame retardant and tracking resistant polyurethane material, and its LOI value decreases from 33.3% (Example 1) to 28.2% (Comparative Example 3). This may be because without the addition of siloxane containing a hindered amine structure, nitroxide free radicals and alkoxy free radicals cannot be decomposed, achieving a good free radical quenching flame retardant effect, and at the same time, a silicon dioxide layer cannot be formed under high temperature conditions to effectively isolate oxygen.

[0234] By comparing Comparative Example 4 and Example 1, it can be seen that when no layered nano-zirconium phosphate is added, the LOI value thereof also decreases relatively significantly, from 33.3% (Example 1) to 27.3% (Comparative Example 4). This may be because the absence of layered nano-zirconium phosphate cannot form a stable interface layer in the TPU matrix, thereby effectively protecting the polymer matrix from further ignition and degradation. At the same time, when no nano-zirconium phosphate is contained, a stable carbon layer cannot be formed during the combustion process, making it difficult to effectively isolate oxygen and heat and prevent further oxidation and combustion of the polymer, thereby reducing the LOI value of Comparative Example 4.

[0235] It can be seen from the data in Table 1 that the halogen-free flame retardant and tracking-resistant polyurethane material prepared by the present invention has excellent flame retardant properties and tracking-resistant properties. By comparing the LOI and UL-94 data of Examples 1-9 and Comparative Example 2, it can be seen that only 10-15 parts of phosphorus-based flame retardants, 3-5 parts of layered nano zirconium phosphates, and 2-4 parts of hindered amine structure siloxanes are needed to add, and the flame retardant properties of the halogen-free flame retardant polyurethane material are better than those of the flame retardant polyurethane material (Comparative Example 2) with 16.66wt% di(2-di-tert-butylterephthalate)formate (DMMP) and 3wt% zinc oxide. At the same time, compared with Comparative Example 2 without the addition of fluorphlogopite, Examples 1-9 all passed the CTI test requirements, that is, there will be no obvious damage to the surface of the material under a high voltage of 600V; the material containing the hindered amine structure The structured siloxane will decompose into nitrogen oxide free radicals and alkoxy free radicals at high temperature. When the content of hindered amine structured siloxane is too high, the generated alkoxy free radicals will not promote the β degradation of polypropylene and aggravate the free radical chain degradation reaction of PP. For example, when the amount of 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine is increased from 2 parts to 4 parts (Example 4), it can pass the V-0 level of UL-94, and the limiting oxygen index is increased from 35.5% (Example 3) to 36.1% (Example 4). With the increase of the amount of flame retardant added, the flame retardant performance of flame-retardant polypropylene shows an upward trend. When the addition amount is 15 parts of polyaryl phosphate, 5 parts of layered nano zirconium phosphate material, and 2 parts of hindered amine structure siloxane (Example 8), the limiting oxygen index of the flame retardant polypropylene material reaches 41.0%, passing the UL-94 test V-0 level. From the test results of Examples 1-9, it can be seen that the halogen-free flame retardant and tracking-resistant polyurethane material has excellent flame retardant properties by using different contents of flame retardants, flame retardant auxiliary agents, and layered nano zirconium phosphate materials.

[0236] From the data in Table 1, it can be seen that after the polyurethane elastomer is blended with flame retardants, flame retardant adjuvants, etc., Example 1 performs best in terms of breaking strength, but the oxygen index is not the highest, indicating that it is better than other examples in terms of mechanical strength, but the flame retardant performance is not top-notch. Example 6 performs best in terms of elongation at break, showing good flexibility. Example 8 performs best in terms of oxygen index, showing the best flame retardant performance, but the breaking strength and elongation at break are relatively low, which may mean that while improving the flame retardant performance, certain mechanical properties are sacrificed. Compared with Examples 1-9, Comparative Example 2 is not optimal in all performance indicators.

[0237] It can be seen from the data in Table 1 that after the polyurethane elastomer is blended with flame retardants, flame retardant auxiliary agents, etc., the breaking strength and breaking elongation will decrease with the increase of the added amount of flame retardants, flame retardant auxiliary agents, etc. Compared with Comparative Example 2, it can be seen that the embodiment can have relatively excellent flame retardant properties without much decrease in mechanical strength.

[0238] It can be seen from the data in Table 1 that the polyurethane elastomer modified by fluorphlogopite blending has been significantly improved in terms of tracking resistance. All examples passed the 600V tracking resistance test, which not only meets the requirements of national standards such as GB / T 6553-2014 and GB / T3048.7-2007, but also meets the requirements of CTI values.

[0239] The above embodiments are preferred implementation schemes of the present invention. In addition, the present invention may also be implemented in other ways. Any obvious replacement without departing from the concept of the present invention is within the protection scope of the present invention.

Claims

1. A halogen-free flame-retardant and tracking-resistant polyurethane material, characterized in that: The invention comprises the following raw materials in parts by weight: 100 parts of thermoplastic polyurethane elastomer, 10-15 parts of phosphorus-based flame retardant, 3-5 parts of layered nano zirconium phosphate, 3-5 parts of anti-tracking agent, 5-15 parts of toughening agent, 2-4 parts of flame retardant auxiliary agent and 2-4 parts of surface modifier.

2. The halogen-free flame-retardant and tracking-resistant polyurethane material according to claim 1, characterized in that: The flame retardant auxiliary agent is a siloxane containing a hindered amine structure.

3. The halogen-free flame-retardant and tracking-resistant polyurethane material according to claim 2, characterized in that: The preparation method of each portion of the hindered amine structure-containing siloxane comprises the following steps: (R1), add 180-200 parts of organic solvent and 15-20 parts of cyanuric chloride into the reaction kettle at a temperature of 0-25°C, and stir evenly; (R2), dissolving 20-25 parts of alkoxysilane and 0.05-0.1 parts of hindered amine monomer in 7-10 parts of organic solvent respectively, and slowly adding them into the reaction kettle within 1-4 hours, and at the same time, dropping 18-25 parts of acid binding agent-water solution into the reaction kettle, and continuing the reaction for 1-6 hours after the dropwise addition is completed; (R3), heating to 45-65°C, slowly dropping 25-35 parts of a mixed aqueous solution of a diamine monomer and an acid binding agent into the reaction kettle within 1-3 hours, and continuing the reaction for 1-6 hours after the dropwise addition is completed to obtain a reaction solution; (R4), filtering, washing and vacuum drying the reaction solution to obtain a siloxane containing a hindered amine structure.

4. The halogen-free flame-retardant and tracking-resistant polyurethane material according to claim 3, characterized in that: The organic solvent is one or more of acetone, cyclohexanone, butanone, toluene, and ethyl acetate; the alkoxysilane is one or more of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, and γ-aminopropylmethyldiethoxysilane; the hindered amine monomer is one or more of 2,4-bis-[N-n-butyl-N-(1-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidinyl)amino]-6-(2-hydroxyethylamino)-1,3,5-triazine, 4-hydroxy-2,2,6,6-tetramethyl-1-(1-phenylethoxy)piperidine, and tetramethylpiperidinamine.

5. The halogen-free flame-retardant and tracking-resistant polyurethane material according to claim 3, characterized in that: The concentration of the acid-binding agent-water solution is 3-8 mol / L; the concentration of the mixed aqueous solution of the diamine monomer and the acid-binding agent is 10-30 wt %, and the mass ratio of the diamine monomer to the acid-binding agent in the mixed aqueous solution of the diamine monomer and the acid-binding agent is 2-4:3-5; the acid-binding agent is one or more of sodium hydroxide, sodium acetate, sodium carbonate, and triethylamine; and the diamine monomer is one or more of ethylenediamine, tetramethyldiamine, butanediamine, and p-phenylenediamine.

6. The halogen-free flame-retardant and tracking-resistant polyurethane material according to claim 1, characterized in that: The phosphorus-based flame retardant is one or more of polyaryl phosphate, ammonium polyphosphate, organic phosphinate, tris(β-chloroethyl) phosphate, and dimethyl methylphosphonate.

7. The halogen-free flame-retardant and tracking-resistant polyurethane material according to claim 1, characterized in that: The anti-tracking additive is one or more of talc, hydrotalcite, and fluorphlogopite.

8. The halogen-free flame-retardant and tracking-resistant polyurethane material according to claim 1, characterized in that: The surface modifier is one or more of 3-aminopropyltriethoxysilane and 3-methacryloxypropyltrimethoxysilane.

9. The halogen-free flame-retardant and tracking-resistant polyurethane material according to claim 1, characterized in that: The toughening agent is one or more of maleic anhydride grafted polypropylene elastomer, methyl methacrylate-butadiene-styrene, liquid acrylic rubber, and liquid polybutadiene rubber.

10. A method for preparing the halogen-free flame-retardant and tracking-resistant polyurethane material according to any one of claims 1 to 9, characterized in that: The steps include: (S1), taking thermoplastic polyurethane elastomer, phosphorus-based flame retardant, layered nano zirconium phosphate, anti-tracking agent, toughening agent, flame retardant auxiliary agent and surface modifier according to weight parts, and setting aside; (S2), mixing a thermoplastic polyurethane elastomer, a phosphorus-based flame retardant, a layered nano zirconium phosphate, an anti-tracking agent, a toughening agent, a flame retardant aid and a surface modifier in a high-speed mixer to obtain a mixture; (S3), adding the mixture into a twin-screw extruder for melt extrusion and granulation to obtain a halogen-free, flame-retardant and tracking-resistant polyurethane material.

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