A tpu wire and a method for manufacturing the same

Abstract

The application provides a TPU wire and a preparation method thereof, and belongs to the technical field of polyurethane.The TPU wire is prepared from the following raw materials in parts by weight: modified graphene oxide 3-5 parts, flame-retardant ionic liquid 7-10 parts, plasticizer 1-3 parts, stabilizer 0.5-1 part, dispersant 0.1-0.3 part, and thermoplastic polyurethane elastomer 70-80 parts.The TPU wire prepared by the application has good flame retardancy, excellent mechanical properties, high compatibility between various raw materials, low cost, excellent performance, a simple and efficient preparation method, and can be used as a flame-retardant TPU wire, and has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyurethane, in particular to a TPU wire and a preparation method thereof. BACKGROUND

[0002] Thermoplastic polyurethane elastomer, also known as thermoplastic polyurethane rubber, 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 linear carbon atoms, and the chemical structure between AB segments is diisocyanate.

[0003] The conventional flame retardants used in TPU compositions are halogen-based, i.e. they contain bromine, chlorine, etc. However, due to the ever-present considerations for the environment and safety, halogen-free flame retardants are now popular, but they can present challenges for TPU compositions. Conventional readily available halogen-free flame retardants, such as those based on organic phosphates (e.g. resorcinol bis(diphenyl phosphate) (RDP) and bisphenol-A bis(diphenyl phosphate) (BPADP)) do not make flame retardant TPU compositions with good smoke suppression. The TPU industry continues to seek halogen-free TPU compositions with good smoke suppression and flame retardancy.

[0004] US 2003 / 0166749 A1 discloses a flame-retardant thermoplastic polyurethane comprising melamine cyanurate as a flame retardant and improving its mechanical properties by adding up to 2 wt% of at least one crosslinker component. Examples of the disclosed crosslinker are trimethylolpropane, pentaerythritol, amine, 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, etc.

[0005] US 2003 / 0166749 A1 also discloses a method of producing a flame-retardant thermoplastic polyurethane by mixing the components by methods known to those skilled in the art, such as combining. This patent document does not disclose the need to add the crosslinker, such as diisocyanate, in the form of a concentrated solution in at least one polyurethane.

[0006] DE 103 43 121 A1 discloses thermoplastic polyurethanes comprising metal hydroxides as flame retardants. One of the characteristics of these thermoplastic polyurethanes is a particularly high molecular weight, at least 60,000 g / mol. The crosslinking of the thermoplastic polyurethanes is not described in this specification.

[0007] WO 2006 / 121549 A1 discloses thermoplastic polyurethanes comprising halogen-free flame retardants. The flame retardants described in WO 2006 / 121549 A1 comprise an organic phosphinate component, an organic phosphate component and a polyol. According to the specification, the flame retardants are mixed by methods known to the person skilled in the art, such as by combining. However, the patent does not disclose that flame-retardant thermoplastic polyurethanes can be obtained by adding crosslinking agents together with the flame retardants.

[0008] The methods of the prior art are capable of producing flame-retardant thermoplastic polyurethanes, but only by using high filler amounts relative to the flame retardants to achieve sufficiently high flame-retardant effects. In particular, for halogen-free compounds, high filler amounts are required to achieve sufficient flame-retardant effects. Conventional flame retardants are melamine compounds and phosphorus-containing compounds and also metal hydroxides, and the proportion of these compounds which needs to be added to achieve sufficiently good flame-retardant effects is 20 to 60% by weight.

[0009] The disadvantage of this high additive content is that the mechanical properties of the composite thermoplastic polyurethane materials are impaired and their sensible use in the market is restricted. The first factor which leads to a reduction in the mechanical properties is the high filler content, and secondly the addition of specific materials during the production process reduces the molar mass, which also leads to a reduction in the mechanical properties. SUMMARY

[0010] The object of the present application is to propose a TPU wire and a preparation method thereof, which has good flame retardancy, good mechanical properties, high compatibility between various raw materials, low cost, good performance, simple and efficient preparation method, can be used as a flame-retardant TPU wire, and has a broad application prospect.

[0011] The technical scheme of the present application is as follows:

[0012] The present application provides a TPU wire, which is prepared from the following raw materials in parts by weight: modified graphene oxide 3-5 parts, flame-retardant ionic liquid 7-10 parts, plasticizer 1-3 parts, stabilizer 0.5-1 part, dispersant 0.1-0.3 part, and thermoplastic polyurethane elastomer 70-80 parts.

[0013] As a further improvement of the present application, the preparation method of the modified graphene oxide is as follows:

[0014] S1. Add graphene oxide into water, add EDC and NHS, stir and activate, add melamine, stir and react, filter, wash, and dry to obtain melamine-modified graphene oxide;

[0015] S2. Add the melamine-modified graphene oxide into water, ultrasonically disperse uniformly, then add phytic acid, heat and reflux to react, filter, wash, and dry to obtain the modified graphene oxide.

[0016] As a further improvement of the present application, the mass ratio of the graphene oxide, EDC, NHS and melamine in step S1 is 10:2-3:1-2:3-5, the time of the stirring activation is 1-2h, and the time of the stirring reaction is 5-7h.

[0017] As a further improvement of the present application, the mass ratio of the melamine graphene oxide and phytic acid in step S2 is 10:3-4, and the time of the heating reflux reaction is 10-14h.

[0018] As a further improvement of the present application, the preparation method of the flame-retardant ionic liquid is as follows:

[0019] T1. Dissolve N-vinylimidazole in dichloromethane, add 10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene, stir at room temperature, then continue to react at elevated temperature, cool to room temperature, remove the solvent under reduced pressure, and refine with ethyl acetate to obtain an intermediate ionic liquid with the following structure:

[0020] T2. Add a silane coupling agent with a double bond and an initiator to the intermediate ionic liquid, heat and stir to react, wash with water, and remove the solvent under reduced pressure to obtain an intermediate ionic liquid 2.

[0021] T3. Dissolve the intermediate ionic liquid 2 and sodium 2-naphthalenesulfonate in water, stir at room temperature, add dichloromethane for extraction, wash the extract with water, remove the solvent under reduced pressure, and dry to obtain a flame-retardant ionic liquid.

[0022] As a further improvement of the present application, the molar ratio of the N-vinylimidazole and 10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene in step T1 is 1-1.1:1, the time of the stirring reaction at room temperature is 0.5-1.5h, the temperature of the continued reaction at elevated temperature is 65-75℃, and the time is 20-24h.

[0023] As a further improvement of the present application, the mass ratio of the intermediate ionic liquid, the silane coupling agent with a double bond and the initiator in step T2 is 10:2-3:0.01-0.015, the silane coupling agent with a double bond is selected from at least one of KH570, A151 and A171, the initiator is selected from at least one of sodium persulfate, potassium persulfate and ammonium persulfate, the temperature of the heating and stirring reaction is 50-60℃, and the time is 3-5h.

[0024] As a further improvement of the present application, the molar ratio of the intermediate ionic liquid 2 and sodium 2-naphthalenesulfonate in step T3 is 1:1, and the time of the stirring reaction at room temperature is 7-9h.

[0025] As a further improvement of the present application, the plasticizer is selected from at least one of glycerol, ethylene glycol, polyethylene glycol; the stabilizer is selected from at least one of calcium hydroxide, calcium oxide, magnesium hydroxide; the dispersant is selected from at least one of calcium stearate, polyethylene wax, oxidized polyethylene wax.

[0026] The present application further protects a preparation method of the above-mentioned TPU wire, comprising the following steps:

[0027] (1) mixing modified graphene oxide and flame-retardant ionic liquid, stirring and mixing for 15-30 min to prepare an additive;

[0028] (2) vacuum drying the thermoplastic polyurethane elastomer, adding a plasticizer, a stabilizer and a dispersant, heating to melt, adding the additive, and melt-extruding the material through a double-screw extruder to obtain blended particles; the barrel temperature is 180-220 DEG C, and the screw rotation speed is 100-200 rpm / min;

[0029] (3) adding the blended particles into a single-screw extruder for extrusion setting and winding to obtain a TPU wire; the barrel temperature is 180-220 DEG C, and the screw rotation speed is 20-70 rpm / min.

[0030] The present application has the following beneficial effects:

[0031] Ionic liquid is an organic salt composed of organic cation and inorganic or organic anion, which is liquid at low temperature, and has the characteristics of not containing halogen and being safe and environmentally friendly. In the present application, 10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene (DOP-Cl) is introduced into N-vinylimidazole, then copolymerized through double bond, and reacted with silane coupling agent with double bond, and then the anion is exchanged, so that the prepared ionic liquid material introduces phosphorus, nitrogen, silicon, sulfur, etc., and achieves the best flame-retardant effect. The ionic liquid itself is not flammable, and has the characteristics of low vapor pressure and high thermal stability, and at the same time, it has catalytic effect on esterification and Friedel-Crafts alkylation reactions. During the decomposition of the polymer, this reaction occurs, and the ionic liquid can improve the carbon residue content and possibly reduce the smoke generation, and plays a role in flame retardation and smoke suppression. At the same time, the ionic liquid can destroy the intermolecular forces of the compound, so as to decompose to play a flame-retardant role. At the same time, the oxygen-containing functional groups of the ionic liquid can destroy their own oxygen-containing functional groups, hinder the reaction with oxygen, and thus achieve the effect of flame retardation.

[0032] The structure of the ionic liquid flame retardant has good solubility, can promote the dispersibility of the modified graphene oxide in the polyurethane, avoids the incompatibility, and can improve the compatibility and processability of the modified graphene oxide with the plastic, has little influence on the mechanical properties and other properties of the plastic, and has an unexpected synergistic effect with the modified graphene oxide, enhances the flame retardant property, and reduces the influence of the additive on the properties of the plastic.

[0033] The application also prepares the modified graphene oxide, the nitrogen content in the melaminated graphene oxide is greatly improved by condensation of the carboxyl on the surface of the graphene oxide and the amino of melamine, so that the flame retardant property is improved, meanwhile, the graphene oxide itself can obviously improve the mechanical properties and wear resistance of the polyurethane material, the amide structure formed is similar to the polyurethane structure, the compatibility of the modified graphene oxide with the polyurethane is improved, the phosphorus content of the modified graphene oxide is improved by further reacting with phytic acid, and the flame retardant property is further improved.

[0034] The TPU wire prepared by the application has good flame retardant property, good mechanical properties, high compatibility between various raw materials, low cost, good performance, simple and efficient preparation method, and can be used as a flame retardant TPU wire, and has a wide application prospect. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0036] Graphene oxide, oxygen content 30-35wt%, flake diameter 15-25μm, thickness <5nm, purchased from Jiangsu Xianfeng Nanometer Material Technology Co., Ltd.

[0037] EDC, 1-ethyl-(3-dimethylaminopropyl) carbonyl diimide, commercially available.

[0038] NHS, N-hydroxysuccinimide, commercially available.

[0039] Preparation example 1 preparation of modified graphene oxide

[0040] The method is as follows:

[0041] S1. 10g of graphene oxide was added to 200mL of water, 2g of EDC and 1g of NHS were added, stirring and activating for 1h, 3g of melamine was added, stirring and reacting for 5h, filtering, washing, and drying to prepare melaminated graphene oxide;

[0042] S2. 10 g of melaminated graphene oxide was added into 200 mL of water, dispersed by 1000 W ultrasonic for 10 min, then 3 g of phytic acid was added, heated to reflux for 10 h, filtered, washed, and dried to obtain modified graphene oxide.

[0043] Preparation of modified graphene oxide in Preparation Example 2

[0044] The method is as follows:

[0045] S1. 10 g of graphene oxide was added into 200 mL of water, 3 g of EDC and 2 g of NHS were added, stirred for activation for 2 h, 5 g of melamine was added, stirred for reaction for 7 h, filtered, washed, and dried to obtain melaminated graphene oxide;

[0046] S2. 10 g of melaminated graphene oxide was added into 200 mL of water, dispersed by 1000 W ultrasonic for 10 min, then 4 g of phytic acid was added, heated to reflux for 14 h, filtered, washed, and dried to obtain modified graphene oxide.

[0047] Preparation of modified graphene oxide in Preparation Example 3

[0048] The method is as follows:

[0049] S1. 10 g of graphene oxide was added into 200 mL of water, 2.5 g of EDC and 1.5 g of NHS were added, stirred for activation for 1.5 h, 4 g of melamine was added, stirred for reaction for 6 h, filtered, washed, and dried to obtain melaminated graphene oxide;

[0050] S2. 10 g of melaminated graphene oxide was added into 200 mL of water, dispersed by 1000 W ultrasonic for 10 min, then 3.5 g of phytic acid was added, heated to reflux for 12 h, filtered, washed, and dried to obtain modified graphene oxide.

[0051] Comparative Preparation Example 1

[0052] Compared with Preparation Example 3, the difference lies in that step S1 is not performed.

[0053] The specific process is as follows:

[0054] 10 g of graphene oxide was added into 200 mL of water, dispersed by 1000 W ultrasonic for 10 min, then 3.5 g of phytic acid was added, heated to reflux for 12 h, filtered, washed, and dried to obtain modified graphene oxide.

[0055] Comparative Preparation Example 2

[0056] Compared with Preparation Example 3, the difference lies in that step S2 is not performed.

[0057] The specific process is as follows:

[0058] To 10 g of graphene oxide in 200 mL of water, 2.5 g of EDC and 1.5 g of NHS were added, stirred for 1.5 h for activation, 4 g of melamine was added, stirred for 6 h for reaction, filtered, washed, dried to obtain modified graphene oxide.

[0059] Preparation of flame-retardant ionic liquid

[0060] The method is as follows:

[0061] The synthetic route is as follows:

[0062]

[0063] T1. 10 mmol of N-vinylimidazole was dissolved in 100 mL of dichloromethane, 10 mmol of 10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene was added, stirred at room temperature for 0.5 h, then heated to 65 °C, and continued to react for 20 h, cooled to room temperature, removed the solvent under reduced pressure, and refined with ethyl acetate to obtain an intermediate ionic liquid with a yield of 70%;

[0064] T2. 2 g of silane coupling agent A151 and 0.01 g of potassium persulfate were added to 10 g of the intermediate ionic liquid, heated to 50 °C, stirred for 3 h for reaction, washed with water, and removed the solvent under reduced pressure to obtain an intermediate ionic liquid 2;

[0065] T3. 10 mmol of the intermediate ionic liquid 2 and 10 mmol of sodium 2-naphthalenesulfonate were dissolved in 200 mL of water, stirred at room temperature for 7 h for reaction, extracted with an equal volume of dichloromethane, washed the extract with water, removed the solvent under reduced pressure, and dried to obtain a flame-retardant ionic liquid.

[0066] Preparation of flame-retardant ionic liquid

[0067] The method is as follows:

[0068] T1. 11 mmol of N-vinylimidazole was dissolved in 100 mL of dichloromethane, 10 mmol of 10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene was added, stirred at room temperature for 1.5 h, then heated to 75 °C, and continued to react for 24 h, cooled to room temperature, removed the solvent under reduced pressure, and refined with ethyl acetate to obtain an intermediate ionic liquid;

[0069] T2. 3 g of silane coupling agent A171 and 0.015 g of ammonium persulfate were added to 10 g of the intermediate ionic liquid, heated to 60 °C, stirred for 5 h for reaction, washed with water, and removed the solvent under reduced pressure to obtain an intermediate ionic liquid 2;

[0070] T3. 10 mmol of intermediate ionic liquid 2 and 10 mmol of sodium 2-naphthalenesulfonate were dissolved in 200 mL of water, and the reaction was stirred at room temperature for 8 h. An equal volume of dichloromethane was added to extract the product, and the extract was washed with water. The solvent was removed under reduced pressure, and the product was dried to obtain the flame-retardant ionic liquid.

[0071] Preparation of the flame-retardant ionic liquid

[0072] The method is as follows:

[0073] T1. 10.5 mmol of N-vinylimidazole was dissolved in 100 mL of dichloromethane, and 10 mmol of 10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene was added. The reaction was stirred at room temperature for 1 h, and then the temperature was raised to 70 °C for 22 h. The reaction was cooled to room temperature, and the solvent was removed under reduced pressure. The product was refined with ethyl acetate to obtain the intermediate ionic liquid.

[0074] T2. 2.5 g of silane coupling agent KH570 and 0.012 g of ammonium persulfate were added to 10 g of the intermediate ionic liquid, and the reaction was stirred at 55 °C for 4 h. The product was washed with water, and the solvent was removed under reduced pressure to obtain the intermediate ionic liquid 2.

[0075] T3. 10 mmol of intermediate ionic liquid 2 and 10 mmol of sodium 2-naphthalenesulfonate were dissolved in 200 mL of water, and the reaction was stirred at room temperature for 8 h. An equal volume of dichloromethane was added to extract the product, and the extract was washed with water. The solvent was removed under reduced pressure, and the product was dried to obtain the flame-retardant ionic liquid.

[0076] Comparative Preparation Example 3

[0077] Compared with Preparation Example 6, the difference is that step T1 is not performed.

[0078] The method is as follows:

[0079] T1. 2.5 g of silane coupling agent KH570 and 0.012 g of ammonium persulfate were added to 10 g of N-vinylimidazole, and the reaction was stirred at 55 °C for 4 h. The product was washed with water, and the solvent was removed under reduced pressure to obtain the intermediate ionic liquid.

[0080] T2. 10 mmol of intermediate ionic liquid and 10 mmol of sodium 2-naphthalenesulfonate were dissolved in 200 mL of water, and the reaction was stirred at room temperature for 8 h. An equal volume of dichloromethane was added to extract the product, and the extract was washed with water. The solvent was removed under reduced pressure, and the product was dried to obtain the flame-retardant ionic liquid.

[0081] Comparative Preparation Example 4

[0082] Compared with Preparation Example 6, the difference is that step T2 is not performed.

[0083] The method is as follows:

[0084] T1. 10.5 mmol of N-vinylimidazole was dissolved in 100 mL of dichloromethane, 10 mmol of 10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene was added, the reaction was stirred at room temperature for 1 h, then the temperature was raised to 70 °C, the reaction was continued for 22 h, the temperature was cooled to room temperature, the solvent was removed under reduced pressure, and the product was purified with ethyl acetate to obtain an intermediate ionic liquid;

[0085] T2. 10 mmol of the intermediate ionic liquid and 10 mmol of sodium 2-naphthalenesulfonate were dissolved in 200 mL of water, the reaction was stirred at room temperature for 8 h, an equal volume of dichloromethane was added for extraction, the extract was washed with water, the solvent was removed under reduced pressure, and the product was dried to obtain a flame-retardant ionic liquid.

[0086] Example 1

[0087] The present example provides a preparation method of a TPU wire, comprising the following steps:

[0088] (1) 3 parts by weight of the modified graphene oxide prepared in Preparation Example 1 and 7 parts by weight of the flame-retardant ionic liquid prepared in Preparation Example 4 were mixed and stirred for 15 min to obtain an additive;

[0089] (2) 70 parts by weight of a thermoplastic polyurethane elastomer was dried at 105 °C under vacuum for 1 h, 1 part by weight of glycerol, 0.5 part by weight of magnesium hydroxide, and 0.1 part by weight of polyethylene oxide wax were added, heated to melt, and the additive prepared in step (1) was added, and the mixture was melt-extruded by a double-screw extruder to obtain blended particles; the barrel temperature was 180 °C, and the screw rotation speed was 100 rpm / min;

[0090] (3) The blended particles were extruded and shaped by a single-screw extruder and wound to obtain a TPU wire; the barrel temperature was 180 °C, and the screw rotation speed was 20 rpm / min.

[0091] Example 2

[0092] The present example provides a preparation method of a TPU wire, comprising the following steps:

[0093] (1) 5 parts by weight of the modified graphene oxide prepared in Preparation Example 2 and 10 parts by weight of the flame-retardant ionic liquid prepared in Preparation Example 5 were mixed and stirred for 30 min to obtain an additive;

[0094] (2) 80 parts by weight of a thermoplastic polyurethane elastomer was dried at 105 °C under vacuum for 1 h, 3 parts by weight of ethylene glycol, 1 part by weight of calcium oxide, and 0.3 part by weight of polyethylene wax were added, heated to melt, and the additive prepared in step (1) was added, and the mixture was melt-extruded by a double-screw extruder to obtain blended particles; the barrel temperature was 220 °C, and the screw rotation speed was 200 rpm / min;

[0095] (3) The blended particles are added to a single screw extruder for extrusion setting and winding to obtain a TPU wire; the barrel temperature is 220℃, and the screw rotation speed is 70 rpm / min.

[0096] Example 3

[0097] The present embodiment provides a preparation method of a TPU wire, comprising the following steps:

[0098] (1) 4 parts by weight of the modified graphene oxide prepared in Preparation Example 3 and 8 parts by weight of the flame-retardant ionic liquid prepared in Preparation Example 6 are mixed and stirred for 20 min to obtain an additive;

[0099] (2) 75 parts by weight of the thermoplastic polyurethane elastomer is vacuum dried at 105℃ for 1 h, 2 parts by weight of polyethylene glycol 1000, 0.7 parts by weight of calcium hydroxide, and 0.2 parts by weight of calcium stearate are added, heated to melt, the additive prepared in step (1) is added, and the material is prepared by melt extrusion through a twin-screw extruder to obtain blended particles; the barrel temperature is 200℃, and the screw rotation speed is 150 rpm / min;

[0100] (3) The blended particles are added to a single screw extruder for extrusion setting and winding to obtain a TPU wire; the barrel temperature is 200℃, and the screw rotation speed is 50 rpm / min.

[0101] Comparative Example 1

[0102] Compared with Example 3, the difference is that the modified graphene oxide is prepared in Comparative Preparation Example 1.

[0103] Comparative Example 2

[0104] Compared with Example 3, the difference is that the modified graphene oxide is prepared in Comparative Preparation Example 2.

[0105] Comparative Example 3

[0106] Compared with Example 3, the difference is that the flame-retardant ionic liquid is prepared in Comparative Preparation Example 3.

[0107] Comparative Example 4

[0108] Compared with Example 3, the difference is that the flame-retardant ionic liquid is prepared in Comparative Preparation Example 4.

[0109] Comparative Example 5

[0110] Compared with Example 3, the difference is that no modified graphene oxide is added.

[0111] The specific process is as follows:

[0112] (1) 12 parts by weight of the flame-retardant ionic liquid prepared in Preparation Example 6 is stirred and mixed for 20 min to obtain an additive;

[0113] (2) 75 parts by weight of thermoplastic polyurethane elastomer was dried at 105°C under vacuum for 1 h, 2 parts by weight of polyethylene glycol 1000, 0.7 parts by weight of calcium hydroxide and 0.2 parts by weight of calcium stearate were added, heated to melt, the additive prepared in step (1) was added, and the material was melt-extruded by a twin-screw extruder to obtain blended particles; the barrel temperature was 200°C, and the screw rotation speed was 150 rpm / min;

[0114] (3) The blended particles were added to a single-screw extruder for extrusion setting and winding to obtain a TPU wire; the barrel temperature was 200°C, and the screw rotation speed was 50 rpm / min.

[0115] Comparative Example 6

[0116] The difference compared with Example 3 is that no flame-retardant ionic liquid is added.

[0117] The details are as follows:

[0118] (1) 12 parts by weight of the modified graphene oxide prepared in Preparation Example 3 was stirred and mixed for 20 min to obtain an additive;

[0119] (2) 75 parts by weight of thermoplastic polyurethane elastomer was dried at 105°C under vacuum for 1 h, 2 parts by weight of polyethylene glycol 1000, 0.7 parts by weight of calcium hydroxide and 0.2 parts by weight of calcium stearate were added, heated to melt, the additive prepared in step (1) was added, and the material was melt-extruded by a twin-screw extruder to obtain blended particles; the barrel temperature was 200°C, and the screw rotation speed was 150 rpm / min;

[0120] (3) The blended particles were added to a single-screw extruder for extrusion setting and winding to obtain a TPU wire; the barrel temperature was 200°C, and the screw rotation speed was 50 rpm / min.

[0121] Comparative Example 7

[0122] The difference compared with Example 3 is that no modified graphene oxide and flame-retardant ionic liquid are added.

[0123] The details are as follows:

[0124] (1) 75 parts by weight of thermoplastic polyurethane elastomer was dried at 105°C under vacuum for 1 h, 2 parts by weight of polyethylene glycol 1000, 0.7 parts by weight of calcium hydroxide and 0.2 parts by weight of calcium stearate were added, heated to melt, and the material was melt-extruded by a twin-screw extruder to obtain blended particles; the barrel temperature was 200°C, and the screw rotation speed was 150 rpm / min;

[0125] (2) The blended particles are added to a single screw extruder for extrusion setting and winding to obtain a TPU wire; the barrel temperature is 200 DEG C, and the screw rotation speed is 50 rpm / min.

[0126] Mechanical property test of test example 1

[0127] The TPU blended particles prepared in the examples 1-3 or the comparative examples 1-6 of the present application are further processed into 5-type dumbbell pieces with a thickness of 1.0 mm for mechanical property test. The results are shown in Table 1.

[0128] The tensile strength and elongation at break test is carried out according to GB / T528-2009 “Determination of tensile stress-strain properties of vulcanized or thermoplastic rubber”, and the tensile rate is 500 mm / min.

[0129] Table 1

[0130] Group Tensile strength (MPa) Elongation at break (%) Example 1 55.9 605 Example 2 55.6 602 Example 3 56.2 610 Comparative Example 1 54.2 595 Comparative Example 2 54.0 590 Comparative Example 3 54.8 598 Comparative Example 4 53.4 586 Comparative Example 5 49.9 550 Comparative Example 6 52.8 578 Comparative Example 7 48.2 540

[0131] From the above table, it can be seen that the TPU material prepared in the examples 1-3 of the present application has good mechanical properties.

[0132] Flame retardant property test of test example 2

[0133] The TPU blended particles prepared in the examples 1-3 or the comparative examples 1-6 of the present application are further processed into standard samples for flame retardant property test. The results are shown in Table 2.

[0134] The vertical burning test is carried out according to GB / T2408-2021 “Determination of the burning behavior of plastics Horizontal and vertical methods”, and the sample is a flame retardant sample with a thickness of 3.2 mm.

[0135] The limiting oxygen index test is carried out according to GB / T2406.2-2009 “Determination of the burning behavior of plastics Part 2: Room temperature test Oxygen index method”, and type IV oxygen index sample is used, and the ignition method is diffusion ignition method.

[0136] Table 2

[0137] Group Vertical flame rating Limiting oxygen index (%) Example 1 V0 41.5 Example 2 V0 41.2 Example 3 V0 41.9 Comparative Example 1 V1 26.7 Comparative Example 2 V1 27.2 Comparative Example 3 V1 28.0 Comparative Example 4 V1 26.1 Comparative Example 5 V2 24.9 Comparative Example 6 V2 23.2 Comparative Example 7 HB 19.0

[0138] From the above table, it can be seen that the TPU material prepared in the examples 1-3 of the present application has good flame retardant properties.

[0139] The above description is only the preferred embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A TPU wire, characterized in that, Prepared from the following raw materials by weight parts: modified graphene oxide 3-5 parts, flame-retardant ionic liquid 7-10 parts, plasticizer 1-3 parts, stabilizer 0.5-1 parts, dispersing agent 0.1-0.3 parts, thermoplastic polyurethane elastomer 70-80 parts; the preparation method of the modified graphene oxide is as follows: S1. The graphene oxide is added to water, EDC and NHS are added, stirring activation, melamine is added, stirring reaction, filtration, washing, drying, melamine graphene oxide is prepared; S2. The melamine graphene oxide is added to water, ultrasonic dispersion is uniform, then phytic acid is added, heating reflux reaction, filtration, washing, drying, modified graphene oxide is prepared.

2. The TPU monofilament of claim 1, wherein, The mass ratio of the graphene oxide, EDC, NHS and melamine in step S1 is 10:2-3:1-2:3-5, the stirring activation time is 1-2h, and the stirring reaction time is 5-7h.

3. The TPU monofilament of claim 1, wherein, The mass ratio of the melamine graphene oxide and phytic acid in step S2 is 10:3-4, and the heating reflux reaction time is 10-14h.

4. The TPU monofilament of claim 1, wherein, The preparation method of the flame-retardant ionic liquid is as follows: T1. Dissolve N-vinylimidazole in dichloromethane, add 10-chloro-9,10-dihydro-9-oxa-10- phosphaphenanthrene, stir the reaction at room temperature, then continue the reaction with heating, cool to room temperature, remove the solvent under reduced pressure, refine with ethyl acetate to produce an intermediate ionic liquid, which has the following structure: ; T2. The silane coupling agent with double bond and initiator are added to the intermediate ionic liquid, heating stirring reaction, water washing, removing the solvent under reduced pressure, and the intermediate ionic liquid 2 is prepared; T3. The intermediate ionic liquid 2 and sodium 2-naphthalenesulfonate are dissolved in water, stirring reaction at room temperature, adding dichloromethane extraction, water washing of the extract, removing the solvent under reduced pressure, drying, and the flame-retardant ionic liquid is prepared.

5. The TPU monofilament of claim 4, wherein, The molar ratio of the N-vinylimidazole and 10-chloro-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in step T1 is 1-1.1:1, the stirring reaction time at room temperature is 0.5-1.5h, the temperature for continuing reaction is 65-75℃, and the time is 20-24h.

6. The TPU monofilament of claim 4, wherein, The mass ratio of the intermediate ionic liquid, silane coupling agent with double bond and initiator in step T2 is 10:2-3:0.01-0.015, the silane coupling agent with double bond is selected from at least one of KH570, A151 and A171, the initiator is selected from at least one of sodium persulfate, potassium persulfate and ammonium persulfate, the heating stirring reaction temperature is 50-60℃, and the time is 3-5h.

7. The TPU monofilament of claim 4, wherein The molar ratio of the intermediate ionic liquid 2 and sodium 2-naphthalenesulfonate in step T3 is 1:1, and the stirring reaction time at room temperature is 7-9h.

8. The TPU monofilament of claim 1, wherein, The plasticizer is selected from at least one of glycerol, ethylene glycol and polyethylene glycol; the stabilizer is selected from at least one of calcium hydroxide, calcium oxide and magnesium hydroxide; and the dispersing agent is selected from at least one of calcium stearate, polyethylene wax and oxidized polyethylene wax.

9. A process for the production of a TPU strand as claimed in any of claims 1 to 8, characterized in that The following steps are included: (1) The modified graphene oxide and flame-retardant ionic liquid are mixed, stirring and mixing for 15-30min, and the additive is prepared; (2) The thermoplastic polyurethane elastomer is vacuum dried, plasticizers, stabilizers and dispersants are added, heated to melt, additives are added, and the material is melt-extruded by a double-screw extruder to obtain blended particles; the barrel temperature is 180-220°C, and the screw rotation speed is 100-200 rpm / min; (3) The blended particles are added to a single-screw extruder for extrusion, sizing and winding to obtain a TPU wire; the barrel temperature is 180-220°C, and the screw rotation speed is 20-70 rpm / min.

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