A highly transparent, highly resilient, flame-retardant thermoplastic polyurethane elastomer and its preparation method and application

Abstract

The present invention discloses a thermoplastic polyurethane elastomer material and a preparation method thereof. The thermoplastic polyurethane elastomer material comprises 25-45wt% of aliphatic diisocyanate, 40-65wt% of macromolecular diol, 4-25wt% of chain extender A and chain extender B, and 0.01-0.2wt% of catalyst. The polyurethane elastomer has a tensile strength greater than 40MPa, a light transmittance greater than 92%, a haze less than 1.0, a rebound rate greater than 99%, a rebound time less than 1s, and a flame retardant grade of V2 or above. It can be used to prepare extruded films, sheets, wires and pipe products with high requirements for transparency, resilience, UV resistance and flame retardancy, and is particularly suitable for car cover film products.

Description

Technical Field

[0001] The present invention relates to the field of thermoplastic polyurethane elastomers, and in particular to a highly transparent, highly resilient, flame-retardant thermoplastic polyurethane elastomer and a preparation method and application thereof. The thermoplastic polyurethane elastomer has high transparency, high resilience and flame-retardant properties, and is particularly suitable for preparing films, sheets and pipes with transparency and flame retardancy. Technical Background

[0002] Thermoplastic polyurethane elastomers have excellent physical and mechanical properties, wear resistance, media resistance, environmental resistance and temperature resistance. They have a wide range of adjustable hardness, are suitable for many processing methods, and have diverse molecular structures. They can meet the needs of different performance and are widely used in various industries.

[0003] With the popularity of cars, people have higher and higher requirements for the comfort, beauty and health performance of cars. When cars are exposed to sunlight for a long time, the paint surface will change color, affecting the appearance of the car. Car protective film gradually appears under this background. Car film has super toughness, strength and tear resistance, and after installation, it can isolate the car paint from the air and protect the paint surface for a long time.

[0004] At present, the car cover films on the market mainly use two materials: PVC film and TPU film. However, PVC film has the disadvantages of easy aging and poor repairability. TPU film is rich in variety. The TPU film prepared by certain polymerization can meet most performance requirements, such as UV resistance, super toughness, wear resistance, easy adhesion, anti-collision and scratch resistance, anti-oxidation, anti-scratch, and long-term protection of car paint.

[0005] The existing TPU substrate layer of car film has the following main problems: (1) The rebound resilience is slightly poor, which affects the construction efficiency; (2) The traditional TPU substrate layer is not flame retardant, which is easy to cause fire accidents during the production, storage, transportation, vehicle film construction and vehicle use of the car film, which is inconsistent with the current application requirements of automobile development.

[0006] Patent CN109438670A discloses a highly transparent soft thermoplastic polyurethane elastomer and its preparation method and application. By introducing dihydroxysulfonic acid quaternary ammonium salt to destroy the regularity of the molecular chain and reduce the crystallization of the hard segment, a polyurethane material with improved transparency is obtained. However, the physical and mechanical properties of the sample are low, and the sample does not have flame retardant properties.

[0007] Patent CN111378272A discloses a thermoplastic polyurethane paint protection film and a preparation method thereof, wherein a polyurethane car cover film with good comprehensive performance is obtained by blending and modifying a mixed thermoplastic polyolefin resin, but the sample also does not have flame retardant properties.

[0008] Patent CN111909504A discloses a polyurethane flame-retardant film for invisible car cover, its preparation method and use. By introducing polyvinylidene chloride and chlorinated polyethylene through blending modification, the extruded film has certain flame-retardant properties, but the tensile strength and transparency of the film are reduced.

[0009] Therefore, preparing a thermoplastic polyurethane elastomer material with high resilience, high transparency and flame retardant properties is of great significance for solving related problems in the construction and use of existing car cover films. Summary of the invention

[0010] The object of the present invention is to provide a highly transparent and highly resilient flame-retardant thermoplastic polyurethane elastomer and a preparation method and application thereof. The thermoplastic polyurethane elastomer provided by the present invention has good flame retardant properties without adding other flame retardants, the chain extender contains phosphorus elements or halogens with flame retardant properties, the flame retardant properties are stable, there is no migration problem, and the material has excellent transparency and resilience, UV yellowing resistance, wet and hot hydrolysis resistance, and weather resistance, and can be applied to films, sheets, pipes, wires and other fields, especially suitable for car cover film application fields.

[0011] Another object of the present invention is to provide a method for preparing the thermoplastic polyurethane elastomer material, which adopts a one-step method for continuous production and has a simple and easy process.

[0012] To achieve the above object, the present invention provides the following technical solutions:

[0013] A thermoplastic polyurethane elastomer material, comprising the following components, based on the total weight of components (1) to (4) being 100%:

[0014]

[0015]

[0016] Wherein, the chain extender B has the following structure:

[0017]

[0018] in:

[0019] W is an OH or NH2 group; M is a C or N or O atom; x is an integer from 0 to 20; y is an integer from 0 to 20; z is an integer from 0 to 20;

[0020] R1 and R2 are each independently selected from the following groups: a C1-C20 straight chain or branched alkyl group or a C1-C20 straight chain or branched halogenated alkyl group; preferably one or more of methyl, ethyl, propyl, isopropyl, isobutyl, -CH2Cl, -CH2Br, -CH2F, -CH2-CH2Cl, -CH2-CH2Br, -CH2-CH2F, -CH2-CH2-CH2Cl, -CH2-CH2-CH2Br, -CH2-CH2-CH2F, -CH(CH3)-CH2Cl, -CH(CH3)-CH2Br, -CH(CH3)-CH2F, -CH(CH2Cl)-CH2Cl, -CH(CH2Br)-CH2Br, -CH(CH2F)-CH2F.

[0021] The aliphatic diisocyanate of the present invention is selected from 4,4'-methylene dicyclohexyl diisocyanate, 2,4'-methylene dicyclohexyl diisocyanate and / or 2,2'-methylene dicyclohexyl diisocyanate (H 12 The present invention can be selected from one or more of the following: MDI), hexamethylene diisocyanate (HDI) and 1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane, pentamethylene 1,5-diisocyanate, butylene 1,4-diisocyanate, 1,10-decane diisocyanate, isophorone diisocyanate (IPDI), 2,4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, 1,4-cyclohexane dimethylene diisocyanate, 1,3-cyclohexane dimethylene diisocyanate, 1,3-cyclohexane diisocyanate or 1,4-cyclohexane diisocyanate (CHDI), preferably 4,4'-methylene dicyclohexyl diisocyanate, 2,4'-methylene dicyclohexyl diisocyanate and / or 2,2'-methylene dicyclohexyl diisocyanate (HDI). 12 One or more of cyclohexane diisocyanate (MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 1,4-cyclohexanedimethylene diisocyanate, 1,3-cyclohexanedimethylene diisocyanate, 1,3-cyclohexane diisocyanate or 1,4-cyclohexane diisocyanate (CHDI).

[0022] The polyol of the present invention is selected from one or more of polyester polyol, polylactone polyol, polyether polyol or polycarbonate polyol, preferably one or more of polycaprolactone diol, polycarbonate diol and polytetramethylene ether diol, and the number average molecular weight of the polyol is 700-4000 g / mol, preferably 1000-3000 g / mol;

[0023] The polyester polyol of the present invention can be prepared by esterification or transesterification reaction of diol with dicarboxylic acid, anhydride or carboxylic ester;

[0024] The diol used in the preparation of the polyester polyol of the present invention is preferably one or more of aliphatic and aromatic diols, more preferably one or more of diols having 2 to 12 carbon atoms, including but not limited to one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, 1,4-cyclohexanedimethanol, decanediol and dodecanediol, and further preferred diol is 1,4-butanediol or 1,6-hexanediol;

[0025] The dicarboxylic acid, anhydride or carboxylic acid ester used in the preparation of the polyester polyol of the present invention is one or more of aliphatic and aromatic dicarboxylic acids or anhydrides or carboxylic acid esters; preferably one or more of dicarboxylic acids, anhydrides or carboxylic acid esters having 4 to 15 carbon atoms, more preferably one or more of phthalic acid, phthalic anhydride, dimethyl phthalate, dimethyl terephthalate, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedioic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, phthalic anhydride and tetrahydrophthalic anhydride; further preferably one or more of adipic acid, phthalic anhydride and tetrahydrophthalic anhydride;

[0026] In the preparation process of the polyester polyol of the present invention, the molar ratio of the diol to the dicarboxylic acid, anhydride or carboxylic acid ester is preferably 1.0-3.0, more preferably 1.02-2.0.

[0027] The polylactone polyol of the present invention is preferably polycaprolactone polyol, which is prepared from ε-caprolactone monomer and initiator under the initiation of a catalyst;

[0028] The initiator used in the preparation of the polylactone polyol of the present invention is one or more of diols, diamines, alcohol amines and polyols, preferably one or more of ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, diethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanediol, trimethylolpropane, pentaerythritol, 3,3'-dichloro-4,4'-diaminodiphenylmethane, diethyltoluenediamine, monoethanolamine and diethanolamine; more preferably one or more of ethylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, TMP and pentaerythritol.

[0029] The polycarbonate polyol of the present invention can be synthesized by phosgene method, carbon dioxide regulated copolymerization method, cyclic carbonate ring-opening polymerization method or ester exchange method;

[0030] The polycarbonate polyol of the present invention is preferably synthesized by transesterification reaction between diol and carbonate;

[0031] In the process of synthesizing polycarbonate polyol by transesterification of the present invention, the diol is preferably one or more of 1,2-ethylene glycol, 1,4-butanediol (BDO), 1,5-pentanediol (PDO) and 1,6-hexanediol (HDO); more preferably 1,4-butanediol (BDO) and / or 1,5-pentanediol (PDO). The carbonate is preferably dimethyl carbonate and diethyl carbonate; more preferably dimethyl carbonate;

[0032] The polyether polyol of the present invention is a polyether polyol prepared by reacting an initiator with an epoxy compound containing 2 to 6 carbon atoms;

[0033] The initiator used in the preparation process of the polyether polyol of the present invention is one or more of small molecule polyols, small molecule polyamines and small molecule alcoholamines; the initiator is preferably one or more of water, propylene glycol, glycerol, trimethylolpropane, ethylenediamine pentaerythritol, xylitol, triethylenediamine, sorbitol, ethylene glycol, bisphenol A and toluene diamine; more preferably one or more of water, propylene glycol and glycerol;

[0034] The epoxy compound used in the preparation process of the polyether polyol of the present invention is preferably one or more of ethylene oxide, propylene oxide and tetrahydrofuran (THF);

[0035] The polyether polyol of the present invention is preferably polyethylene glycol prepared by the reaction of ethylene oxide and ethylene glycol, polypropylene glycol prepared by the reaction of propylene oxide and propylene glycol, or polytetramethylene ether glycol (PTMEG) prepared by the reaction of water and tetrahydrofuran (THF), and a copolyether of the reaction product of THF and ethylene oxide or THF and propylene oxide; the more preferred polyether polyol is polytetramethylene ether glycol (PTMEG).

[0036] The chain extender A of the present invention comprises a small molecule diol and / or a diamine having 2 to 15 carbon atoms, and is selected from one or more of ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,5-pentanediol, isoprene glycol, neopentyl glycol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, 1,4-cyclohexanedimethanol, decanediol and dodecanediol, 1,3-propylenediamine, 1,4-butanediamine, p-phenylenediamine, and biphenylenediamine; preferably one or more of 1,2-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, isoprene glycol, and 3-methyl-1,5-pentanediol.

[0037] The chain extender B of the present invention is preferably selected from one or more of the following structures:

[0038]

[0039] The molar ratio of the chain extender A to the chain extender B of the present invention is 10:1 to 1:8.

[0040] The isocyanate index (molar ratio of -NCO to -OH) of the thermoplastic polyurethane elastomer material of the present invention is 0.9 to 1.1, preferably 0.98 to 1.02.

[0041] The catalyst of the present invention is selected from one or more of an organic bismuth catalyst, an organic tin catalyst, an organic zinc catalyst or a titanate catalyst; preferably one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, tetraisopropyl titanate, bismuth isooctanoate, bismuth neodecanoate and tetrabutyl titanate.

[0042] The raw materials for preparing the thermoplastic polyurethane elastomer material of the present invention may also include mixing aids, which include light stabilizers, antioxidants, and hydrolysis stabilizers. The amount of the mixing aids added is 0.5-3wt% based on the total mass of diisocyanate, polyol, chain extender, and catalyst.

[0043] The method for preparing a highly transparent and highly resilient flame-retardant thermoplastic polyurethane elastomer of the present invention comprises the following steps:

[0044] The isocyanate, polyol, chain extender, catalyst and optional mixing aid are fed into the screw of the twin-screw extruder through a feeding and perfusion system; then, a melt extrusion reaction is carried out, and underwater pelletization and ripening and drying are carried out to obtain the highly transparent, highly resilient and flame-retardant thermoplastic polyurethane elastomer;

[0045] The extrusion temperature of the twin-screw extruder is 120-240°C;

[0046] The actual screw speed of the twin-screw extruder is 100-300 rpm.

[0047] The polyurethane elastomer has a tensile strength greater than 40 MPa, a light transmittance higher than 92%, a haze lower than 1.0, a rebound rate greater than 99%, a rebound time lower than 1 s, and a flame retardancy grade of V2 or above. It can be used to prepare extruded films, sheets, wires and pipe products with high requirements on transparency, resilience, UV resistance and flame retardancy, and is particularly suitable for car cover film products.

[0048] The invention also relates to the use of the thermoplastic polyurethane elastomer in the fields of preparing films, sheets, extruded pipes, extruded cables and the like.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] 1) The present invention uses a special chain extender B with a larger side group as a mixed chain extender to prepare a TPU material, and utilizes the steric hindrance effect of the larger side group to destroy the regularity of the molecular chain, reduce the degree of crystallization of the material, and improve transparency, thereby obtaining an extruded film material with low haze and excellent transparency.

[0051] 2) The present invention introduces phosphorus and / or halogen elements with flame retardant properties into the TPU molecular chain through a special chain extender B, so that the TPU material has intrinsic flame retardant properties and avoids the migration instability problem of the flame retardant.

[0052] 3) The special chain extender B used in the present invention contains at least one primary amine group, and introduces a polyurea group into the TPU main chain, which increases the hydrogen bonding force between molecules, improves the physical and mechanical properties of the material, improves the resilience of the extruded film, and is beneficial to improving the construction efficiency of the finished car cover film. DETAILED DESCRIPTION

[0053] The present invention is further described below in conjunction with embodiments. The following examples are only used as illustrations of the present invention and are not intended to limit the scope of the present invention.

[0054] The sources of some components in the embodiments and comparative examples are as follows:

[0055] H 12 MDI: Wanhua Chemical Group Co., Ltd.

[0056] HXDI: Wanhua Chemical Group Co., Ltd.;

[0057] Polycaprolactone polyol 1: Ingevity, number average molecular weight 1000;

[0058] Polycaprolactone polyol 2: Ingevity, number average molecular weight 2000;

[0059] Polycaprolactone polyol 3: Ingevity, number average molecular weight 3000;

[0060] Polytetramethylene ether polyol 1: BASF, number average molecular weight 1000;

[0061] Polytetramethylene ether polyol 2: BASF, number average molecular weight 2000;

[0062] Polycarbonate polyol 1: Dasero, number average molecular weight 2000;

[0063] Chain extender 1: 1,4-butanediol;

[0064] Chain extender 2: (Synthesized by referring to the following patent: Organophosphorusflame retardanthardener and a manufacturing method thereof Republic of KR2016043195 A2016-04-21)

[0065]

[0066] Chain Extender 3:

[0067]

[0068] Chain Extender 4:

[0069]

[0070] Catalyst 1: Stannous octoate, Catalyst 2: Bismuth neodecanoate

[0071] Additive package: A self-prepared additive package containing an antioxidant, a light stabilizer, and a hydrolysis-resistant additive, the composition and mass ratio of the additive package are as follows (antioxidant 1010 / UV292 / carbodiimide monomer=1:3:1).

[0072] The following properties of the obtained polyurethane elastomer are tested by the specified method:

[0073] 1) Tensile strength and elongation at break: ASTM D412

[0074] 2) Transmittance and haze: ASTM D1003

[0075] 3) Moisture and heat resistance (double 85) aging: The cast 0.15 mm film was placed in a constant temperature and humidity chamber at 85°C and 85% humidity for 2 weeks, and the tensile strength was tested according to ASTM D412.

[0076] 4) UV aging resistance: UVA340 (0.15mm TPU film), irradiation intensity 0.77W / m 2 , conditions: 70℃, irradiation for 8h; then 50℃, condensation for 4h, a total of 3000h testing, to investigate the change of color difference dE.

[0077] 5) Rebound time and rebound rate: 0.15mm thick film, 30mm*150mm long strip, stretched 30%, let it stand for 30s and then let the film rebound. Time the rebound time, let it stand for 5min, and then test the rebound rate.

[0078] 6) Flame retardant properties: UL94.

[0079] Example 1

[0080] A thermoplastic polyurethane elastomer comprising the following components:

[0081] 1) H 12 MDI: 35.39 wt%;

[0082] 2) Polycaprolactone polyol 1: 50 wt%;

[0083] 3) Chain extender 1 + chain extender 2: 14.6 wt%;

[0084] 4) Catalyst 1: 0.01 wt%;

[0085] Wherein, the molar ratio of chain extender 1 to chain extender 2 is 1:1;

[0086] Wherein, the preparation method is as follows:

[0087] The above components (H 12 MDI, polycaprolactone polyol 1, chain extender 1, chain extender 2, catalyst 1) are added to a twin-screw extruder through a feeding and perfusion system, and thermoplastic polyurethane elastomer particles are obtained after reaction extrusion, underwater pelletizing and drying. The particles are processed into parts and tested according to relevant test methods; the extruder temperature is set at 120-240°C and the screw speed is 200rpm.

[0088] Example 2

[0089] A thermoplastic polyurethane elastomer comprising the following components:

[0090] 1) H 12 MDI: 36.3wt%;

[0091] 2) Polycaprolactone polyol 2: 52 wt%;

[0092] 3) Chain extender 1 + chain extender 3: 11.68 wt%;

[0093] 4) Catalyst 2: 0.02 wt%;

[0094] Wherein, the molar ratio of chain extender 1 to chain extender 3 is 10:1;

[0095] The preparation method of the thermoplastic polyurethane is the same as that in Example 1.

[0096] Example 3

[0097] A thermoplastic polyurethane elastomer comprising the following components:

[0098] 1) H 12 MDI: 28.05wt%;

[0099] 2) Polycaprolactone polyol 3: 55 wt%;

[0100] 3) Chain extender 1 + chain extender 3: 16.85 wt%;

[0101] 4) Catalyst 1: 0.1 wt%;

[0102] Wherein, the molar ratio of chain extender 1 to chain extender 3 is 1:3;

[0103] The preparation method of the thermoplastic polyurethane is the same as that in Example 1.

[0104] Example 4

[0105] A thermoplastic polyurethane elastomer comprising the following components:

[0106] 1) H 12 MDI: 34wt%;

[0107] 2) polytetramethylene ether polyol 1: 45wt%;

[0108] 3) Chain extender 1 + chain extender 4: 20.95wt%;

[0109] 4) Catalyst 2: 0.05 wt%;

[0110] The molar ratio of chain extender 1 to chain extender 4 is 1:8. The preparation method of the thermoplastic polyurethane is the same as that of Example 1.

[0111] Example 5

[0112] A thermoplastic polyurethane elastomer comprising the following components:

[0113] 1) HXDI: 38.3 wt%;

[0114] 2) polytetramethylene ether polyol 2: 40 wt%;

[0115] 3) Chain extender 1 + chain extender 4: 21.6 wt%;

[0116] 4) Catalyst 1: 0.1 wt%;

[0117] Wherein, the molar ratio of chain extender 1 to chain extender 4 is 5:1; the preparation method of the thermoplastic polyurethane is the same as that of Example 1.

[0118] Example 6

[0119] A thermoplastic polyurethane elastomer comprising the following components:

[0120] 1) HXDI: 26.9 wt%;

[0121] 2) polycarbonate polyol 1: 60 wt%;

[0122] 3) Chain extender 1 + chain extender 4: 13 wt%;

[0123] 4) Catalyst 2: 0.1 wt%;

[0124] Wherein, the molar ratio of chain extender 1 to chain extender 4 is 5:1; the preparation method of the thermoplastic polyurethane is the same as that of Example 1.

[0125] Example 7

[0126] A thermoplastic polyurethane elastomer comprising the following components:

[0127] 1) H 12 MDI: 36.1wt%;

[0128] 2) Polycaprolactone polyol 1: 55 wt%;

[0129] 3) Chain extender 1 + chain extender 2: 8.7 wt%;

[0130] 4) Catalyst 1: 0.2 wt%;

[0131] The molar ratio of chain extender 1 to chain extender 2 is 8:1;

[0132] The preparation method of the thermoplastic polyurethane is the same as that in Example 1.

[0133] Example 8

[0134] A thermoplastic polyurethane elastomer comprising the following components:

[0135] 1) H 12 MDI: 38.7 wt%;

[0136] 2) polytetramethylene ether polyol 1: 40wt%;

[0137] 3) Chain extender 1 + chain extender 3: 21.27 wt%;

[0138] 4) Catalyst 2: 0.03 wt%;

[0139] Wherein, the molar ratio of chain extender 1 to chain extender 3 is 1:5;

[0140] The preparation method of the thermoplastic polyurethane is the same as that in Example 1.

[0141] Example 9

[0142] A thermoplastic polyurethane elastomer comprising the following components:

[0143] 1) H 12 MDI: 32.7 wt%;

[0144] 2) Polycaprolactone polyol 1: 48 wt%;

[0145] 3) Chain extender 1 + chain extender 4: 19.27 wt%;

[0146] 4) Catalyst 1: 0.03 wt%;

[0147] 5) Auxiliary agent package: the addition amount is 1.5% of the total mass of components 1) / 2) / 3)4), dissolved in polyol and added to the extruder through the feeding and injection system;

[0148] Wherein, the molar ratio of chain extender 1 to chain extender 4 is 1:8;

[0149] The preparation method of the thermoplastic polyurethane is the same as that in Example 1.

[0150] Comparative Example 1

[0151] A thermoplastic polyurethane elastomer comprising the following components: 1) H 12 MDI: 37.36wt%;

[0152] 2) Polycaprolactone polyol 2: 52 wt%;

[0153] 3) Chain extender 1: 10.62 wt%;

[0154] 4) Catalyst 2: 0.02 wt%;

[0155] The preparation method is the same as Example 1.

[0156] Comparative Example 2

[0157] A thermoplastic polyurethane elastomer comprising the following components: 1) H 12 MDI: 43.9 wt%;

[0158] 2) polytetramethylene ether polyol 1: 45wt%;

[0159] 3) Chain extender 1: 11.05 wt%;

[0160] 4) Catalyst 2: 0.05 wt%;

[0161] The preparation method is the same as Example 1.

[0162] Comparative Example 3

[0163] A thermoplastic polyurethane elastomer comprises the following components: 1) HXDI: 32.3 wt%;

[0164] 2) polycarbonate polyol 1: 55 wt%;

[0165] 3) Chain extender 1: 12.6 wt%;

[0166] 4) Catalyst 2: 0.1 wt%;

[0167] The preparation method is the same as Example 1.

[0168] The products obtained in the above embodiments and comparative examples were tested for performance, wherein the transmittance and haze test samples were all 0.15 mm cast films, the tensile strength and elongation at break tests were conducted in accordance with the ASTM D412 standard, and the 0.15 mm film was tested; the flame retardant test samples were 3 mm injection molded test pieces, and the test was conducted in accordance with the UL94 standard. The test results are shown in Table 1 below:

[0169] Table 1 Performance test results of the embodiments and comparative examples

[0170]

[0171] The thermoplastic polyurethane elastomer prepared by the present invention has excellent physical and mechanical properties, transparency, resilience, hydrolysis resistance and UV aging resistance. At the same time, the material has good flame retardant properties, wherein the tensile strength is greater than 40MPa, the light transmittance is higher than 92%, the haze is lower than 1.0, the rebound rate is greater than 99%, the rebound time is lower than 1s, and the flame retardant grade is above V2.

[0172] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as limiting the present invention. Those skilled in the art will appreciate that, under the guidance of this specification, some modifications or adjustments may be made to the present invention. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A thermoplastic polyurethane elastomer, comprising the following components, based on the total weight of components (1) to (4) being 100%: (1) at least one aliphatic diisocyanate 25-45 wt% in, The aliphatic diisocyanate is selected from one or more of 4,4'-methylene dicyclohexyl diisocyanate, 2,4'-methylene dicyclohexyl diisocyanate, 2,2'-methylene dicyclohexyl diisocyanate, hexamethylene diisocyanate, 1-isocyanate-3,3,5-trimethyl-5-isocyanate methylcyclohexane, pentamethylene 1,5-diisocyanate, butylene 1,4-diisocyanate, 1,10-decane diisocyanate, isophorone diisocyanate, 2,4-hexahydrotoluene diisocyanate, 2,6-hexahydrotoluene diisocyanate, 1,4-cyclohexane dimethylene diisocyanate, 1,3-cyclohexane dimethylene diisocyanate, 1,3-cyclohexane diisocyanate or 1,4-cyclohexane diisocyanate; (2) 40 to 65 wt % of at least one polyol; (3) at least one chain extender A and chain extender B 4-25 wt%; Wherein, the molar ratio of the chain extender A to the chain extender B is 10:1 to 1:8; (4) 0.01-0.2 wt% catalyst; Wherein, the chain extender A is selected from at least one of small molecule diols and / or diamines having 2 to 15 carbon atoms, and the chain extender B has the following structure: in: W is an OH or NH2 group; M is a C or N or O atom; x is an integer from 0 to 20; y is an integer from 0 to 20; z is an integer from 0 to 20; R1 and R2 are each independently selected from the following groups: C1-C20 straight chain or branched chain alkyl or C1-C20 straight chain or branched chain halogenated alkyl.

2. The thermoplastic polyurethane elastomer according to claim 1, wherein the content of each component is:

3. The thermoplastic polyurethane elastomer according to claim 1, wherein in the chain extender B, R1 and R2 are each independently selected from the following groups: methyl, ethyl, propyl, isopropyl, isobutyl, -CH2Cl, -CH2Br, -CH2F, -CH2-CH2Cl, -CH2-CH2Br, -CH2-CH2F, -CH2-CH2-CH2Cl, -CH2-CH2-CH2Br, -CH2-CH2-CH2F, -CH(CH3)-CH2Cl, -CH(CH3)-CH2Br, -CH(CH3)-CH2F, -CH(CH2Cl)-CH2Cl, -CH(CH2Br)-CH2Br, -CH(CH2F)-CH2F.

4. The thermoplastic polyurethane elastomer according to any one of claims 1 to 2, wherein the polyol is selected from one or more of polyester polyols, polyether polyols or polycarbonate polyols; The number average molecular weight of the polyol is 700-4000 g / mol.

5. The thermoplastic polyurethane elastomer according to claim 4, wherein the polyol is selected from one or more of polycaprolactone diol, polycarbonate diol, and polytetramethylene ether glycol; The number average molecular weight of the polyol is 1000-3000 g / mol.

6. The thermoplastic polyurethane elastomer according to claim 1 or 2, wherein the chain extender A is selected from one or more of ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, 1,4-butanediol, 1,5-pentanediol, isoprene glycol, neopentyl glycol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, 1,4-cyclohexanedimethanol, decanediol and dodecanediol, 1,3-propylenediamine, 1,4-butanediamine, p-phenylenediamine, and benzyl diamine.

7. The thermoplastic polyurethane elastomer according to any one of claims 1 to 3, wherein the chain extender B is selected from one or more of the following structures:

8. The thermoplastic polyurethane elastomer according to any one of claims 1-2, wherein the catalyst is selected from one or more of an organic bismuth catalyst, an organic tin catalyst, an organic zinc catalyst or a titanate catalyst.

9. The thermoplastic polyurethane elastomer according to claim 8, wherein the catalyst is selected from one or more of dibutyltin dilaurate, stannous octoate, dibutyltin diacetate, tetraisopropyl titanate, bismuth isooctanoate, bismuth neodecanoate and tetrabutyl titanate.

10. A method for preparing a thermoplastic polyurethane elastomer according to any one of claims 1 to 9, characterized in that: The following steps are involved: Aliphatic diisocyanate, polyol, chain extender and catalyst are fed into the screw of a twin-screw extruder through a feeding and perfusion system; then melt extrusion reaction is carried out, and underwater pelletizing and drying are carried out to obtain the thermoplastic polyurethane elastomer.

11. The preparation method according to claim 10, wherein: The extrusion temperature of the twin-screw extruder is 120-240°C; The actual screw speed of the twin-screw extruder is 100-300 rpm.

12. Use of the thermoplastic polyurethane elastomer according to any one of claims 1 to 9 for preparing films, sheets, extruded pipes and extruded cables.

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