Thermoplastic polyurethane elastomer, polyurethane foam material as well as preparation method and application of thermoplastic polyurethane elastomer and polyurethane foam material

Abstract

The invention belongs to the technical field of polymer materials, and provides a thermoplastic polyurethane elastomer, a polyurethane foam material and a preparation method and application of the thermoplastic polyurethane elastomer and the polyurethane foam material. The complex viscosity of the thermoplastic polyurethane elastomer is 300-100000 Pa.s under the conditions of 160 DEG C and 0.01 Hz; the storage modulus of the thermoplastic polyurethane elastomer under the conditions of 160 DEG C and 1 Hz is recorded as G ', the loss modulus is recorded as G '', and G' / G'' is more than or equal to 0.01 and less than or equal to 100. Through the design of complex viscosity and the ratio G ' / G' of the storage modulus to the loss modulus, the polyurethane foam material has excellent foamability, and the polyurethane foam material prepared by foaming the polyurethane foam material has the advantages of high foaming ratio, small density, uniform and controllable crust thickness, uniform cell size, stable cells, low shrinkage rate and high foaming efficiency. The high-resilience foam material has high resilience and excellent mechanical properties, and fully meets the performance requirements on high-performance foam materials in the industry.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer materials, and in particular relates to a thermoplastic polyurethane elastomer, a polyurethane foam material, and a preparation method and application thereof. Background Art

[0002] Thermoplastic polyurethane elastomer (TPU) has the characteristics of high tension, high tensile force, good strength and toughness, aging resistance, wear resistance, etc. The foam material prepared with TPU as the matrix is ​​widely used in packaging, industry, transportation, daily necessities, medical products and other fields due to its light weight, breathability, environmental protection, good resilience and other advantages.

[0003] In recent years, the foaming process of thermoplastic polyurethane foam materials mainly includes bead foaming, plate foaming, embryo mold foaming, mucell (micro foaming) injection molding, etc. For example, WO2007082838A1 discloses a foam based on thermoplastic polyurethane, and its preparation method includes: extruding thermoplastic polyurethane with a Shore hardness of A44-A84 to obtain particles with an average diameter of 0.2-10 mm, impregnating the particles with 0.1-40% by weight of a foaming agent based on the total weight of the particles in an aqueous suspension under pressure and 100-150°C, and then cooling the suspension of thermoplastic polyurethane containing the foaming agent to 20-95°C, decompressing, and obtaining polyurethane foam. CN102229709A discloses an environmentally friendly polyurethane foam profile, which is directly prepared by a physical gas foaming method using a polyurethane raw material containing a modifier in the presence of a physical gas foaming agent, so that the foaming density is 0.08-0.80g / cm 3 , the average pore size is 10-100 μm, the pores are uniform, and there is no skin structure. However, the density of polyurethane foam products is currently high, and the resilience is poor, generally around 50-55%; moreover, as a crystalline polymer, TPU will experience a sudden drop in viscosity near the melting point. If the viscosity is too low, the pore size of the foamed product will be larger, and the probability of pore breakage will increase, and the thickness of the skin will be uneven, which will lead to poor rebound and low bending stiffness of the product, making it difficult to meet the needs of professional functional sports shoes.

[0004] Supercritical fluid foaming technology uses inert gases such as supercritical CO2 and N2 as foaming agents. Compared with traditional physical foaming agents such as alkanes and freons, supercritical fluid foaming agents have the advantages of wide sources, environmental friendliness, and low combustion. However, polyurethane particles foamed with supercritical CO2 have serious shrinkage problems. This severe shrinkage not only significantly increases the density of the foaming material, but also causes obvious wrinkles and depressions on the surface of the foaming material, and uneven crusting, which seriously affects the subsequent use of the foaming material. The commonly used method now is to improve the shrinkage problem by blending other polymers, dimensional stabilizers or nucleating agents. For example, CN103709726A discloses an extruded foaming thermoplastic polyurethane elastomer bead, which contains 100 parts by weight of thermoplastic polyurethane elastomer, 0.01-0.5 parts by weight of foaming nucleating agent, and 0.01-0.2 parts by weight of antioxidant. Supercritical fluid is used in the foaming process, and the addition amount is 1-40 parts by weight; the foaming nucleating agent is talc, silica, calcium carbonate, zeolite, graphite, alumina, calcium hydroxide, aluminum hydroxide, zinc borate, etc.; by adding the foaming nucleating agent, the particle density is reduced and the pores are uniform, but such a method will not only increase the cost, but also reduce the foaming ratio, and cannot effectively solve the problem of uneven skinning.

[0005] Therefore, developing a thermoplastic polyurethane foam material with uniform and controllable crust thickness, high foaming ratio and good resilience is an urgent problem to be solved in this field. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a thermoplastic polyurethane elastomer, a polyurethane foam material, and a preparation method and application thereof. By designing the ratio of complex viscosity and storage modulus to loss modulus, the thermoplastic polyurethane elastomer has excellent foaming performance, and the polyurethane foam material obtained by foaming has a high foaming ratio, low density, uniform and controllable crust thickness, excellent resilience and mechanical properties.

[0007] To achieve this object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a thermoplastic polyurethane elastomer, wherein the complex viscosity of the thermoplastic polyurethane elastomer at 160°C and 0.01 Hz is 300-100000 Pa·s; the storage modulus of the thermoplastic polyurethane elastomer at 160°C and 1 Hz is denoted as G', and the loss modulus is denoted as G'', and 0.01≤G' / G''≤100.

[0009] The thermoplastic polyurethane elastomer provided by the present invention has a specific complex viscosity and a ratio of storage modulus to loss modulus G' / G'', and has excellent foamability through parameter design. The polyurethane foam material obtained by foaming the thermoplastic polyurethane elastomer has a high foaming ratio, a low density, a uniform and controllable skin thickness, a uniform and stable cell size, a low shrinkage rate, high resilience and excellent mechanical properties.

[0010] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0011] In the present invention, the complex viscosity, storage modulus (G') and loss modulus (G'') of the thermoplastic polyurethane elastomer can be obtained by testing with a rotational rheometer.

[0012] Exemplarily, the method for testing using a rotational rheometer is as follows: using an instrument model MCR 102e produced by Anton Paar, in the range of 120-180°C, the test frequency is set to 0.0001-200 Hz, and the test piece is cut into a disc with a diameter of 15-25 mm and a thickness of 0.01-5 mm for frequency scanning. The complex viscosity is taken at 160°C and 0.01 Hz, and the storage modulus G' and loss modulus G'' are taken at 160°C and 1 Hz.

[0013] In the present invention, the complex viscosity of the thermoplastic polyurethane elastomer at 160° C. and 0.01 Hz is 300-100000 Pa·s, for example, 400 Pa·s, 500 Pa·s, 1000 Pa·s, 2000 Pa·s, 5000 Pa·s, 8000 Pa·s, 10000 Pa·s, 12000 Pa·s, 15000 Pa·s, 18000 Pa·s, 20000 Pa·s, 25000 Pa·s, 30000 Pa·s, 35000 Pa·s, 40000 Pa·s, 45000 Pa·s, 50000 Pa·s, 55000 Pa·s, 60000 Pa·s, 65000 Pa·s, 70000 Pa·s, 75000 Pa·s, 80000 Pa·s, Pa·s, 85000 Pa·s, 90000 Pa·s or 95000 Pa·s, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific point values ​​included in the said range, preferably 300-80000 Pa·s, and further preferably 300-50000 Pa·s.

[0014] The thermoplastic polyurethane elastomer of the present invention has a complex viscosity of 300-100000 Pa·s at 160°C and 0.01 Hz, and can produce a high-expansion-ratio, high-stability polyurethane foam material. If the complex viscosity of the thermoplastic polyurethane elastomer is lower than 300 Pa·s, the stability of the prepared polyurethane foam product is seriously lost, and the foam cells are easily broken; if the complex viscosity of the thermoplastic polyurethane elastomer is higher than 100000 Pa·s, the processing pressure required during the foaming and product molding process is high, and it is difficult to obtain a polyurethane foam product with a high foaming ratio.

[0015] In the present invention, the storage modulus of the thermoplastic polyurethane elastomer at 160°C and 1 Hz is recorded as G', and the loss modulus is recorded as G'', 0.01≤G' / G''≤100, G' / G'' can be 0.02, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 5, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90 or 95, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, preferably 0.01≤G' / G''≤10, and more preferably 0.01≤G' / G''≤1.

[0016] The ratio of the storage modulus to the loss modulus of the thermoplastic polyurethane elastomer at 160° C. and 1 Hz is 0.01-100, and the polyurethane foam material can be foamed to obtain a polyurethane foam material with high foaming ratio, low density, uniform and controllable skin thickness, low shrinkage, excellent resilience and mechanical properties. If G' / G'' is less than 0.01, the foaming ratio of the polyurethane foam material will be significantly reduced, the shrinkage will be high, and the resilience will be reduced; if G' / G'' is greater than 100, the skin thickness of the foam material will be uneven, and obvious shrinkage problems will occur.

[0017] Preferably, the thermoplastic polyurethane elastomer is obtained by reacting isocyanate, polyol and optionally a chain extender.

[0018] Preferably, the thermoplastic polyurethane elastomer is obtained by reacting isocyanate, polyol and chain extender; wherein the isocyanate and chain extender participate in constructing the hard segment structure of the thermoplastic polyurethane elastomer, and the polyol constructs the soft segment structure of the thermoplastic polyurethane elastomer.

[0019] Preferably, the isocyanate includes any one of aliphatic isocyanate, alicyclic isocyanate, and aromatic isocyanate, or a combination of at least two of them, and aliphatic isocyanate and / or alicyclic isocyanate are more preferred.

[0020] Preferably, the isocyanate includes any one of hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, dicyclohexylmethane diisocyanate, and hydrogenated xylylene diisocyanate, or a combination of at least two thereof, and hexamethylene diisocyanate and / or dicyclohexylmethane diisocyanate are further preferred.

[0021] Preferably, the polyol includes any one of polycarboxylate polyol, polyether polyol, polycarbonate polyol, polycaprolactone polyol, or a combination of at least two thereof.

[0022] Preferably, the polyol includes any one or a combination of at least two of polybutylene adipate, polytetramethylene ether glycol, polybutylene adipate / ethylene glycol ester, polycarbonate polyol, polycaprolactone polyol, polyethylene adipate, polyhexylene adipate, polyhexylene adipate / ethylene glycol ester, and polyhexylene adipate / butylene glycol ester.

[0023] Preferably, the number average molecular weight (M n ) is 500-3500 g / mol, for example, it can be 600 g / mol, 800 g / mol, 1000 g / mol, 1200 g / mol, 1500 g / mol, 1800 g / mol, 2000 g / mol, 2200 g / mol, 2500 g / mol, 2800 g / mol, 3000 g / mol, 3200 g / mol or 3400 g / mol, and specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific points included in the range, and further preferably 800-2500 g / mol.

[0024] Preferably, the chain extender is a small molecule compound containing at least 2 (≥2, such as 2, 3, 4, etc., more preferably 2) active hydrogen groups, and the active hydrogen groups include hydroxyl groups and / or amino groups.

[0025] Preferably, the chain extender comprises a small molecule diol and / or a small molecule diamine.

[0026] Preferably, the chain extender includes any one of ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, cyclohexanedimethanol, dihydroxyethylbenzene, propylene diamine, butylene diamine, p-phenylenediamine, biphenylenediamine, and 3,3'-dimethyl-4,4-biphenylenediamine, or a combination of at least two thereof.

[0027] Further preferably, the chain extender includes any one or a combination of at least two of 1,2-ethylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, cyclohexanedimethanol, hydroquinone dihydroxyethyl ether, 1,3-propylenediamine, 1,4-butanediamine, p-phenylenediamine, biphenylenediamine, and 3,3'-dimethyl-4,4-biphenylenediamine.

[0028] Preferably, the Shore hardness of the thermoplastic polyurethane elastomer is 60 A-70 D, for example, it can be 62 A, 65A, 68 A, 70 A, 72 A, 75 A, 78 A, 80 A, 82 A, 85 A, 88 A, 90 A, 92 A, 95 A, 98 A, 100 A, 62D, 65 D or 68 D, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and 80 A-55 D is further preferred, 85 A-100 A is more preferred, and 85A-95 A is particularly preferred.

[0029] Exemplarily, the Shore hardness of the thermoplastic polyurethane elastomer is measured by the method in ASTM D2240-05.

[0030] Preferably, the tensile strength of the thermoplastic polyurethane elastomer is ≥20 MPa, for example, it may be 21 MPa, 22 MPa, 25 MPa, 28 MPa, 30 MPa, 32 MPa, 35 MPa, 38 MPa, 40 MPa or 45 MPa, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and 22-40 MPa is further preferred.

[0031] Preferably, the elongation at break of the thermoplastic polyurethane elastomer is 400%-750%, for example, it may be 420%, 450%, 480%, 500%, 520%, 550%, 580%, 600%, 620%, 650%, 680%, 700%, 720% or 740%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0032] Exemplarily, the tensile strength and elongation at break of the thermoplastic polyurethane elastomer are tested and obtained by the method in ASTM D412.

[0033] Exemplarily, the method for preparing the thermoplastic polyurethane elastomer includes: performing polymerization reaction on isocyanate, polyol and chain extender to obtain the thermoplastic polyurethane elastomer.

[0034] Preferably, the molar amount of NCO groups in the isocyanate is recorded as n1, the total molar amount of active hydrogen groups in the polyol and the chain extender is recorded as n2, and n1:n2 is 1:(0.9-1.1), for example, it can be 1:0.91, 1:0.92, 1:0.93, 1:0.94, 1:0.95, 1:0.96, 1:0.97, 1:0.98, 1:0.99, 1:0.992, 1:0.995, 1:0.998, 1:1, 1:1.012, 1:1.015, 1:1.018, 1:1.02, 1:1.03, 1:1.04, 1:1.05, 1:1.06, 1:1.07, 1:1.08, 1:1.09, etc., and 1:(0.99-1.1) is further preferred.

[0035] Wherein, the total molar amount of active hydrogen groups in the polyol and the chain extender represents the total molar amount of hydroxyl groups and amino groups (if any); when the chain extender is a small molecule diol, the total molar amount of active hydrogen groups in the polyol and the chain extender is the total molar amount of hydroxyl groups; when the chain extender includes a small molecule diamine, the total molar amount of active hydrogen groups in the polyol and the chain extender is the total molar amount of hydroxyl groups and amino groups.

[0036] Preferably, based on the total mass of the isocyanate, the polyol and the chain extender as 100%, the mass of the isocyanate is 12%-35%, for example, it can be 13%, 14%, 15%, 16%, 18%, 20%, 22%, 25%, 28%, 30%, 32% or 34%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, and 15%-30% is further preferred.

[0037] Preferably, based on the total mass of the isocyanate, the polyol and the chain extender as 100%, the mass of the chain extender is 0.7%-25%, for example, it can be 0.8%, 0.9%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23% or 24%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0038] Preferably, the polymerization reaction is carried out in the presence of a catalyst.

[0039] In the present invention, the type of the catalyst is not particularly limited, and any catalyst known in the art that can catalyze the reaction of active hydrogen with NCO groups to generate carbamate groups is suitable for the present invention.

[0040] Preferably, the catalyst includes any one or a combination of at least two of an organic tin catalyst, an amine catalyst, or an organic bismuth catalyst, and further preferably any one or a combination of at least two of dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, or triethylamine.

[0041] Preferably, based on the mass of the polyol as 100%, the mass of the catalyst is 0.001%-0.5%, for example, it can be 0.002%, 0.005%, 0.008%, 0.01%, 0.02%, 0.05%, 0.08%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4% or 0.45%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0042] Preferably, the polymerization reaction is carried out in the presence of an antioxidant.

[0043] Preferably, the antioxidant includes any one of a hindered amine antioxidant, a hindered phenol antioxidant, and a phosphite antioxidant, or a combination of at least two thereof.

[0044] Preferably, based on the mass of the polyol as 100%, the mass of the antioxidant is ≤1%, for example, it can be 0, 0.002%, 0.005%, 0.008%, 0.01%, 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, 0.6%, 0.7%, 0.8% or 0.9%, and specific values ​​between the above points. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific points included in the range, and 0-0.8% is further preferred.

[0045] Preferably, the polymerization reaction is carried out in an extruder.

[0046] Preferably, the extruder comprises a screw extruder, more preferably a twin-screw extruder.

[0047] Preferably, the preparation method of the thermoplastic polyurethane elastomer comprises: uniformly mixing isocyanate, polyol, chain extender and optionally antioxidant to obtain a mixture; injecting the mixture into a screw extruder for polymerization reaction, and then extruding, cooling and granulating to obtain the thermoplastic polyurethane elastomer (granules).

[0048] Preferably, the temperature of the screw extruder is 100-220°C, for example, it can be 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, 200°C or 210°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0049] Preferably, the screw speed of the screw extruder is 100-300 rpm, for example, it can be 120 rpm, 150 rpm, 180 rpm, 200 rpm, 220 rpm, 250 rpm or 280 rpm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0050] Preferably, the pellets obtained by the granulation are cooled to ≤35°C (eg, 18°C, 20°C, 22°C, 25°C, 28°C, 30°C, 32°C, 34°C, etc.) for packaging and storage.

[0051] In a second aspect, the present invention provides a polyurethane foam material, which is obtained by foaming the thermoplastic polyurethane elastomer as described in the first aspect.

[0052] Preferably, the foaming method comprises a supercritical fluid foaming method.

[0053] In a third aspect, the present invention provides a method for preparing the polyurethane foam material according to the second aspect, the preparation method comprising the following steps:

[0054] Using a physical foaming agent to foam the thermoplastic polyurethane elastomer described in the first aspect under pressure; after the foaming is completed, the pressure is released and the elastomer is aged to obtain the polyurethane foam material;

[0055] The foaming includes a first stage of foaming and a second stage of foaming performed sequentially, the temperature of the first stage of foaming is recorded as T1, the temperature of the second stage of foaming is recorded as T2, 5°C≤T2-T1≤20°C;

[0056] The aging temperature is denoted as T3, 0≤T3-T1≤20°C.

[0057] The polyurethane foam material of the present invention is obtained by foaming the thermoplastic polyurethane elastomer provided by the first aspect. On the basis of using a specific thermoplastic polyurethane elastomer, the preparation method further designs a two-stage foaming process. By controlling the temperature, pressure relief and aging process during the foaming process, a polyurethane foam material with high foaming ratio, low density, uniform and controllable skin thickness, uniform pores, low shrinkage, excellent resilience and mechanical properties can be obtained.

[0058] In the present invention, the temperature T2 of the second foaming stage is greater than the temperature T1 of the first foaming stage, and T2-T1 is 5-20°C, for example, it can be 6°C, 8°C, 10°C, 12°C, 14°C, 15°C, 16°C or 18°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0059] In the present invention, the pressure relief is followed by aging, and the aging temperature T3 is ≥ the temperature T1 of the first stage foaming, and T3-T1 is 0-20°C, for example, it can be 1°C, 2°C, 4°C, 5°C, 6°C, 8°C, 10°C, 12°C, 14°C, 15°C, 16°C or 18°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0060] Preferably, the physical foaming agent includes any one of nitrogen, carbon dioxide, methane, propane, butane, and pentane, or a combination of at least two thereof.

[0061] Preferably, the foaming method comprises a supercritical fluid foaming method.

[0062] Preferably, the physical foaming agent comprises nitrogen and / or carbon dioxide, more preferably supercritical nitrogen and / or supercritical carbon dioxide, further preferably supercritical carbon dioxide or a combination of supercritical carbon dioxide and supercritical nitrogen.

[0063] It should be noted that the material form of the thermoplastic polyurethane elastomer is not limited, for example, it can be beads, sheets or plates; the foaming form can be bead foaming, plate foaming, embryo mold foaming, injection molding foaming, etc.

[0064] In a preferred technical solution, the thermoplastic polyurethane elastomer is in the form of beads, and the preparation method comprises: mixing the beads, a physical foaming agent and a solvent to obtain a suspension; foaming the suspension under pressure, and after the foaming is completed, releasing the pressure and ripening to obtain the polyurethane foam material (in the form of beads).

[0065] Preferably, the solvent comprises water.

[0066] Preferably, the mass ratio of the solvent to the beads is (0.5-5):1, for example, it can be 0.6:1, 0.8:1, 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1 or 5:1, etc.

[0067] In another preferred technical solution, the thermoplastic polyurethane elastomer is in the form of a sheet or a plate, and the preparation method comprises: placing the sheet or the plate in a foaming device, filling it with a physical foaming agent, foaming it under pressure, and after the foaming is completed, releasing the pressure and ripening it to obtain the polyurethane foam material (sheet or plate).

[0068] Preferably, the foaming pressure is 10-65 MPa, for example, it can be 15 MPa, 18 MPa, 20 MPa, 22 MPa, 25 MPa, 28 MPa, 30 MPa, 32 MPa, 35 MPa, 38 MPa, 40 MPa, 42 MPa, 45 MPa, 48 MPa, 50 MPa, 52 MPa, 55 MPa or 58 MPa, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0069] Preferably, the temperature of the first foaming stage is 100-160°C, for example, it can be 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C or 155°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0070] Preferably, the first foaming time is 0.1-24 h, for example, it can be 0.2 h, 0.5 h, 1 h, 2 h, 4 h, 5 h, 6 h, 8 h, 10 h, 12 h, 14 h, 15 h, 16 h, 18 h, 20 h, 22 h or 23 h, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, and 0.5-10 h is further preferred.

[0071] Preferably, the temperature of the second foaming stage is 105-180°C, for example, it can be 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C or 175°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0072] Preferably, the second foaming time is 0.05-5 h, for example, it can be 0.1 h, 0.2 h, 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h or 4.5 h, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range, and 0.1-5 h is further preferred.

[0073] In the present invention, the "decompression" means releasing the pressure.

[0074] Preferably, the aging temperature is 100-180°C, for example, it can be 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C, 170°C or 175°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0075] Preferably, the aging time is 0.1-24 h, for example, it can be 0.2 h, 0.5 h, 1 h, 2 h, 4 h, 5 h, 6 h, 8 h, 10 h, 12 h, 14 h, 15 h, 16 h, 18 h, 20 h, 22 h or 23 h, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively enumerates the specific point values ​​included in the range, and 0.1-5 h is further preferred.

[0076] As a preferred technical solution of the present invention, the preparation method comprises the following steps:

[0077] Thermoplastic polyurethane elastomer beads, a physical foaming agent and a solvent are mixed to obtain a suspension; the suspension is subjected to a first stage of foaming and a second stage of foaming in sequence under a pressure of 10-65 MPa; the temperature of the first stage of foaming is 100-160° C., and the time is 0.1-24 h; the temperature of the second stage of foaming is 105-180° C., and the time is 0.05-5 h;

[0078] After the foaming is completed, the pressure is released, and then the mixture is aged at 100-180° C. for 0.1-5 h to obtain the polyurethane foam material (foamed beads).

[0079] Optionally, the polyurethane foam material (foamed beads) is placed in a mold and molded under heat treatment conditions to obtain a molded product (such as a plate).

[0080] Preferably, the heat treatment is performed by using water vapor for heat treatment molding.

[0081] Preferably, the pressure of the water vapor is 0.8-2.5 bar, for example, it can be 1 bar, 1.2 bar, 1.5 bar, 1.8 bar, 2 bar, 2.2 bar or 2.4 bar, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0082] As another preferred technical solution of the present invention, the preparation method comprises the following steps:

[0083] Placing a sheet or plate-shaped thermoplastic polyurethane elastomer in a foaming device, charging a physical foaming agent, and sequentially performing first-stage foaming and second-stage foaming under a pressure of 10-65 MPa; the temperature of the first-stage foaming is 100-160° C., and the time is 0.1-24 h; the temperature of the second-stage foaming is 105-180° C., and the time is 0.05-5 h;

[0084] After the foaming is completed, the pressure is released, and then the material is aged at 100-180° C. for 0.1-5 h to obtain the polyurethane foam material (foamed sheet or foamed board).

[0085] Preferably, the density of the polyurethane foam material is 0.03-0.2 g / cm 3 , for example, it can be 0.04 g / cm 3 , 0.05 g / cm 3 , 0.06 g / cm 3 , 0.08 g / cm 3 , 0.1 g / cm 3 , 0.12 g / cm 3 , 0.15 g / cm 3 or 0.18 g / cm 3 , as well as specific point values ​​between the above point values, due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0086] Preferably, the shrinkage rate of the polyurethane foam material is ≤2%, preferably ≤1.6%, more preferably ≤1.5%, and may be 0.8-1.5%.

[0087] Preferably, the ball rebound rate of the polyurethane foam material is greater than 70%, more preferably greater than or equal to 75%, and may be 75%-82%.

[0088] Preferably, the skin thickness of the polyurethane foam material is ≤100 μm, for example, 15 μm, 20 μm, 30 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 70 μm, 80 μm or 90 μm, preferably 20-100 μm, more preferably 20-40 μm.

[0089] In a fourth aspect, the present invention provides an application of the polyurethane foam material as described in the second aspect in shoe materials, seat materials, tires, decorative materials, cushioning materials, thermal insulation materials, sound insulation materials, toys or sports equipment.

[0090] Preferably, the polyurethane foam material is applied to shoe soles, tires, bicycle seats, interior decorations, cushions, sound insulation pads or children's toys.

[0091] Compared with the prior art, the present invention has the following beneficial effects:

[0092] The thermoplastic polyurethane elastomer provided by the present invention has excellent foaming performance through the design of complex viscosity and the ratio of storage modulus to loss modulus G' / G''. The polyurethane foam material prepared by foaming the thermoplastic polyurethane elastomer has high foaming ratio, low density, uniform and controllable skin thickness, uniform cell size, stable cells, low shrinkage, high rebound performance and excellent mechanical properties, which fully meets the performance requirements of the industry for high-performance foam materials. DETAILED DESCRIPTION

[0093] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0094] As used herein, the terms "comprises," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0095] "Optionally", "optionally" or "either" means that the subsequently described matter or event can or cannot occur, and that the description includes cases where the event occurs and cases where it does not.

[0096] In the following specific embodiments of the present invention, the materials for which the preparation methods are not provided are all commercially available chemicals, and the specific information of the materials is as follows:

[0097]

[0098] In the following specific embodiments of the present invention, the main testing methods for thermoplastic polyurethane elastomers and polyurethane foam materials are as follows:

[0099] (1) Complex viscosity

[0100] The thermoplastic polyurethane elastomer to be tested was made into a disc with a diameter of 20 mm and a thickness of 1 mm. The instrument model MCR 102e produced by Anton Paar was used. The test frequency was set to 0.0001-200 Hz in the range of 120-180°C, and the complex viscosity was recorded at 160°C and 0.01 Hz.

[0101] (2) Storage modulus G' and loss modulus G''

[0102] The thermoplastic polyurethane elastomer to be tested was made into a disc with a diameter of 20 mm and a thickness of 1 mm. The instrument model MCR 102e produced by Anton Paar was used. The test frequency was set to 0.0001-200 Hz in the range of 120-180°C. The storage modulus G' and loss modulus G'' at 160°C and 1 Hz were recorded, and G' / G'' was calculated.

[0103] (3) Hardness

[0104] The 2 mm test piece was made by injection molding and tested according to the method in standard ASTM D2240-05 to obtain the shore A hardness.

[0105] (4) Tensile strength and elongation at break

[0106] The 2 mm test pieces were injection molded and tested according to the method in standard ASTM D412.

[0107] (4) Density

[0108] The test was carried out according to the method in standard ASTM D792.

[0109] (5) Ball rebound

[0110] The test was carried out according to the method in standard ISO 8307-2007.

[0111] (6) Shrinkage

[0112] The test was carried out according to the method in standard ISO 294-4, 2577.

[0113] (7) Crust thickness

[0114] Cut the polyurethane foam material (particles or plates) to be tested into thin slices, observe the uniformity of the pores under an optical microscope, and measure the pore diameter and skin thickness. The skin thickness of the foam material refers to the thickness between the outer skin and the pores observed under an optical microscope. The optical microscope uses the Patriot Digital Observer GE-5, whose software has built-in image measurement function.

[0115] The thermoplastic polyurethane elastomer, polyurethane foam material and preparation method thereof of the present invention are described in detail below by taking a plurality of embodiments as examples, but the thermoplastic polyurethane elastomer, polyurethane foam material and preparation method thereof of the present invention are not limited to these embodiments.

[0116] In the following examples, carbon dioxide and nitrogen used as physical foaming agents are both supercritical fluids.

[0117] Example 1

[0118] A thermoplastic polyurethane elastomer and a preparation method thereof. The preparation method is as follows: by weight, 1 part of PBA-1000, 0.408 parts of HDI, 0.131 parts of 1,4-butanediol, 0.0001 parts of stannous octoate and 0.005 parts of antioxidant 1010 are transported to a pouring system through a gear pump and mixed evenly to obtain a mixture; the mixture is poured on a twin-screw extruder for continuous reaction to synthesize the thermoplastic polyurethane elastomer; the temperatures of zones 1-10 of the twin-screw extruder are respectively 120°C, 150°C, 155°C, 160°C, 160°C, 190°C, 190°C, 190°C, 210°C, 210°C, the die head temperature is 210°C, and the screw speed is 190°C. rpm; the obtained thermoplastic polyurethane elastomer was cooled and pelletized to obtain thermoplastic polyurethane elastomer (TPU) beads, the beads were cooled to 25°C for storage, and injection molded into 2 mm test pieces. The test results are shown in Table 1.

[0119] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: using the TPU beads provided in this embodiment, adding 1 kg of the TPU beads and 1 kg of water into a 20 L high-pressure reactor, charging with 15 MPa of carbon dioxide to form a suspension, then heating to 140°C, maintaining the pressure at 15 MPa, and foaming at a constant temperature for 2 hours, then heating to 150°C, and foaming for 10 minutes; then discharging the gas in the pressure vessel into the atmosphere, aging at a constant temperature of 150°C for 1 hour, and drying to obtain TPU foam beads; filling the TPU foam beads obtained above into a mold of 300 mm in length, 200 mm in width, and 40 mm in thickness, using 1.2 bar pressure water vapor to compress the mold by 15% in the thickness direction to bond the particles into shape, and finally obtaining a molded foam product, which is then placed at room temperature for 48 hours for performance evaluation, and the data are shown in Table 1.

[0120] Example 2

[0121] A thermoplastic polyurethane elastomer and a preparation method thereof. The preparation method is as follows: by weight, 1 part of PTMEG-1000, 0.337 parts of HDI, 0.092 parts of 1,4-butanediol, 0.0003 parts of triethylamine and 0.005 parts of antioxidant 1010 are transported to a pouring system through a gear pump and mixed evenly to obtain a mixture; the mixture is poured on a twin-screw extruder for continuous reaction to synthesize a thermoplastic polyurethane elastomer, the temperatures of zones 1-10 of the twin-screw extruder are respectively: 120°C, 150°C, 155°C, 160°C, 160°C, 190°C, 190°C, 190°C, 210°C, 210°C, the head temperature is 210°C, the screw speed is 190 rpm, the obtained thermoplastic polyurethane elastomer is cooled and pelletized, and the temperature is reduced to below 30°C for storage to obtain TPU beads, which are injection molded 2 mm test piece, the test results are shown in Table 1.

[0122] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: the TPU beads provided in this embodiment are extruded into a 15 mm thick plate through a screw extruder, the plate is placed in a foaming kettle, 5 MPa of carbon dioxide and 15 MPa of nitrogen are filled, the temperature is raised to 115° C., the pressure is maintained at 20 MPa, constant temperature and pressure foaming is performed for 1 h, and then the temperature is raised to 130° C. for foaming for 15 min; then the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmosphere, and the plate is matured at a constant temperature of 130° C. for 0.5 h to obtain a TPU foam plate, the performance evaluation data of which are shown in Table 1.

[0123] Example 3

[0124] A thermoplastic polyurethane elastomer and a preparation method thereof, the preparation method being as follows: by weight, 1 part of PEBA-2000, 0.223 parts of HDI, 0.075 parts of 1,6-hexanediol, 0.0005 parts of stannous octoate and 0.005 parts of antioxidant 1024 are transported to a casting system through a gear pump and mixed evenly to obtain a mixture; the mixture is cast on a twin-screw extruder for continuous reaction to synthesize a thermoplastic polyurethane elastomer, the temperatures of zones 1-10 of the twin-screw extruder are 120°C, 150°C, 155°C, 160°C, 160°C, 190°C, 190°C, 190°C, 210°C, 210°C, the die temperature is 210°C, the screw speed is 190 rpm, the obtained thermoplastic polyurethane elastomer is cooled and pelletized, and stored at a temperature below 25°C to obtain TPU beads, which are injection molded 2 mm test piece, the test results are shown in Table 1.

[0125] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: the TPU beads provided in the present embodiment are injection molded into a small embryo of a midsole of a shoe material, and then placed in a foaming kettle for foaming, filled with 10 MPa carbon dioxide and 15 MPa nitrogen, and then heated to 145°C, maintained at a pressure of 25 MPa, and foamed at a constant temperature and pressure for 3 h, and then heated to 160°C for foaming for 15 min; then the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmosphere, and the foam is matured at a constant temperature of 160°C for 4 h to obtain a large embryo of a foam shoe material, and its performance evaluation data are shown in Table 1.

[0126] Example 4

[0127] A thermoplastic polyurethane elastomer and a preparation method thereof. The preparation method is as follows: by weight, 1 part of PCL-1000, 0.494 parts of HDI, 0.174 parts of 1,4-butanediol, 0.0006 parts of stannous octoate and 0.005 parts of antioxidant 168 are transported to a casting system through a gear pump and mixed evenly to obtain a mixture; the mixture is cast on a twin-screw extruder for continuous reaction to synthesize a thermoplastic polyurethane elastomer, the temperatures of zones 1-10 of the twin-screw extruder are 120°C, 150°C, 155°C, 160°C, 160°C, 190°C, 190°C, 190°C, 210°C, 210°C, the die temperature is 210°C, the screw speed is 190 rpm, the obtained thermoplastic polyurethane elastomer is cooled and pelletized, and the temperature is reduced to below 30°C for storage to obtain TPU beads, which are injection molded 2 mm test piece, the test results are shown in Table 1.

[0128] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: the TPU beads provided in the present embodiment are injection molded into a plate, the plate is placed in a foaming kettle, 5 MPa of carbon dioxide and 15 MPa of nitrogen are charged, the temperature is kept constant and raised to 150° C., the pressure is kept at 20 MPa, constant temperature and pressure foaming is performed for 3 h, and then the temperature is raised to 165° C. and foaming is performed for 15 min; then the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmosphere, and the plate is kept constant at 165° C. for aging for 1 h to obtain an injection-molded TPU foam plate, the performance evaluation data of which are shown in Table 1.

[0129] Example 5

[0130] A thermoplastic polyurethane elastomer and a preparation method thereof. The preparation method is as follows: by weight, 1 part of PCDL-1500, 0.318 parts of HDI, 0.111 parts of 1,4-butanediol, 0.0003 parts of triethylamine and 0.005 parts of antioxidant 1010 are transported to a pouring system through a gear pump and mixed evenly to obtain a mixture; the mixture is poured on a twin-screw extruder for continuous reaction to synthesize a thermoplastic polyurethane elastomer, the temperatures of zones 1-10 of the twin-screw extruder are 120°C, 150°C, 155°C, 160°C, 160°C, 190°C, 190°C, 190°C, 210°C, 210°C, the die temperature is 210°C, the screw speed is 190 rpm, the obtained thermoplastic polyurethane elastomer is cooled and pelletized, and the temperature is reduced to below 30°C for storage to obtain TPU beads, which are injection molded 2 mm test piece, the test results are shown in Table 1.

[0131] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: the TPU beads provided in this embodiment are passed through a screw extruder to obtain a 10 mm thick plate, the plate is placed in a foaming kettle, filled with 7 MPa carbon dioxide and 18 MPa nitrogen, then the temperature is raised to 145°C, the pressure is maintained at 25 MPa for constant temperature and pressure foaming for 3 h, and then the temperature is raised to 160°C for foaming for 15 min; then the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmosphere, and the plate is matured at a constant temperature of 160°C for 0.1 h to obtain a TPU foam plate, the performance evaluation data of which are shown in Table 1.

[0132] Example 6

[0133] A thermoplastic polyurethane elastomer and a preparation method thereof. The preparation method is as follows: by weight, 1 part of PCDL-1500, 0.364 parts of HMDI, 0.065 parts of 1,4-butanediol, 0.003 parts of triethylamine and 0.005 parts of antioxidant 1010 are transported to a pouring system through a gear pump and mixed evenly to obtain a mixture; the mixture is poured on a twin-screw extruder for continuous reaction to synthesize a thermoplastic polyurethane elastomer, the temperatures of zones 1-10 of the twin-screw extruder are 120°C, 150°C, 155°C, 160°C, 160°C, 190°C, 190°C, 190°C, 210°C, 210°C, the die temperature is 210°C, the screw speed is 190 rpm, the obtained thermoplastic polyurethane elastomer is cooled and pelletized, and the temperature is reduced to below 30°C for storage to obtain TPU beads, which are injection molded 2 mm test piece, the test results are shown in Table 1.

[0134] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: the TPU beads provided in this embodiment are passed through a screw extruder to obtain a 10 mm thick plate, the plate is placed in a foaming kettle, filled with 7 MPa carbon dioxide and 18 MPa nitrogen, then the temperature is raised to 145°C, the pressure is maintained at 25 MPa for constant temperature and pressure foaming for 3 h, and then the temperature is raised to 160°C for foaming for 15 min; then the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmosphere, and the plate is matured at a constant temperature of 160°C for 0.1 h to obtain a TPU foam plate, the performance evaluation data of which are shown in Table 1.

[0135] Example 7

[0136] A thermoplastic polyurethane elastomer and a preparation method thereof. The preparation method is as follows: by weight, 1 part of PCDL-1500, 0.297 parts of HDI, 0.131 parts of 1,4-hexanediol, 0.0003 parts of triethylamine and 0.005 parts of antioxidant 1010 are transported to a casting system through a gear pump and mixed evenly to obtain a mixture; the mixture is cast on a twin-screw extruder for continuous reaction to synthesize a thermoplastic polyurethane elastomer, the temperatures of zones 1-10 of the twin-screw extruder are 120°C, 150°C, 155°C, 160°C, 160°C, 190°C, 190°C, 190°C, 210°C, 210°C, the die temperature is 210°C, the screw speed is 190 rpm, the obtained thermoplastic polyurethane elastomer is cooled and pelletized, and the temperature is reduced to below 30°C for storage to obtain TPU beads, which are injection molded 2 mm test piece, the test results are shown in Table 1.

[0137] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: the TPU beads provided in this embodiment are passed through a screw extruder to obtain a 10 mm thick plate, the plate is placed in a foaming kettle, filled with 7 MPa carbon dioxide and 18 MPa nitrogen, then the temperature is raised to 145°C, the pressure is maintained at 25 MPa for constant temperature and pressure foaming for 3 h, and then the temperature is raised to 160°C for foaming for 15 min; then the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmosphere, and the plate is matured at a constant temperature of 160°C for 0.1 h to obtain a TPU foam plate, the performance evaluation data of which are shown in Table 1.

[0138] Example 8

[0139] A thermoplastic polyurethane elastomer and a preparation method thereof, wherein the materials and preparation process are the same as those in Example 2.

[0140] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: the TPU beads provided in this embodiment are extruded into a 15 mm thick plate through a screw extruder, the plate is placed in a foaming kettle, 5 MPa of carbon dioxide and 15 MPa of nitrogen are filled, the temperature is raised to 115° C., the pressure is maintained at 20 MPa, and constant temperature and pressure foaming is performed for 75 min; then the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmosphere, and the plate is matured at a constant temperature of 145° C. for 0.5 h to obtain a TPU foam plate, the performance evaluation data of which are shown in Table 1.

[0141] Example 9

[0142] A thermoplastic polyurethane elastomer and a preparation method thereof, wherein the materials and preparation process are the same as those in Example 2.

[0143] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: the TPU beads provided in this embodiment are extruded into a 15 mm thick plate through a screw extruder, the plate is placed in a foaming kettle, 5 MPa of carbon dioxide and 15 MPa of nitrogen are filled, the temperature is raised to 130° C., the pressure is maintained at 20 MPa, and constant temperature and pressure foaming is performed for 75 min; then the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmosphere, and the plate is matured at a constant temperature of 145° C. for 0.5 h to obtain a TPU foam plate, the performance evaluation data of which are shown in Table 1.

[0144] Example 10

[0145] A thermoplastic polyurethane elastomer and a preparation method thereof, wherein the materials and preparation process are the same as those in Example 2.

[0146] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: the TPU beads provided in this embodiment are extruded into a 15 mm thick plate through a screw extruder, the plate is placed in a foaming kettle, 5 MPa of carbon dioxide and 15 MPa of nitrogen are filled, the temperature is raised to 115° C., the pressure is maintained at 20 MPa, constant temperature and pressure foaming is performed for 1 h, and then the temperature is raised to 130° C. for foaming for 15 min; then the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmosphere, and the TPU foam plate is obtained by cooling. The performance evaluation data thereof are shown in Table 1.

[0147] Comparative Example 1A

[0148] A thermoplastic polyurethane elastomer and a preparation method thereof. The preparation method is as follows: by weight, 1 part of PBA-1000, 0.15 parts of HDI, 0.008 parts of 1,4-butanediol, 0.0006 parts of stannous octoate and 0.005 parts of antioxidant 1010 are transported to a pouring system through a gear pump and mixed evenly to obtain a mixture; the mixture is poured on a twin-screw extruder for continuous reaction to synthesize the thermoplastic polyurethane elastomer, the temperatures of zones 1-10 of the twin-screw extruder are 120°C, 150°C, 155°C, 160°C, 160°C, 190°C, 190°C, 190°C, 210°C, 210°C, the die head temperature is 210°C, and the screw speed is 190°C. rpm, the obtained thermoplastic polyurethane elastomer was cooled and pelletized to obtain thermoplastic polyurethane elastomer (TPU) beads, the beads were cooled to 25°C for storage, and injection molded into 2 mm test pieces. The test results are shown in Table 1.

[0149] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: using the TPU beads provided in this comparative example, adding 1 kg of the TPU beads and 1 kg of water into a 20 L high-pressure reactor, charging with 15 MPa carbon dioxide to form a suspension, then heating to 110°C, maintaining the pressure at 15 MPa, and foaming for 3 hours; then discharging the gas in the pressure vessel into the atmosphere, drying to obtain TPU foam beads; filling the TPU foam beads obtained above into a mold of 300 mm in length, 200 mm in width, and 40 mm in thickness, using water vapor at a pressure of 1.2 bar to compress the mold by 15% in the thickness direction to bond the particles into shape, finally obtaining a molded foam product, then placing it at room temperature for 48 hours, and evaluating its performance, the data being shown in Table 1.

[0150] Comparative Example 1B

[0151] A polyurethane foam material and a preparation method thereof. The preparation method is as follows: using the TPU beads provided in Comparative Example 1A, a polyurethane foam material is prepared according to the same method as Example 2, and the performance evaluation data thereof is shown in Table 1.

[0152] Comparative Example 2A

[0153] A thermoplastic polyurethane elastomer and a preparation method thereof. The preparation method is as follows: by weight, 1 part of PCDL-1500, 0.833 parts of HDI, 0.388 parts of 1,4-butanediol, 0.0001 parts of triethylamine and 0.005 parts of antioxidant 1010 are transported to a pouring system through a gear pump and mixed evenly to obtain a mixture; the mixture is poured on a twin-screw extruder for continuous reaction to synthesize a thermoplastic polyurethane elastomer, the temperatures of zones 1-10 of the twin-screw extruder are 120°C, 150°C, 155°C, 160°C, 160°C, 190°C, 190°C, 190°C, 210°C, 210°C, the die temperature is 210°C, the screw speed is 190 rpm, the obtained thermoplastic polyurethane elastomer is cooled and pelletized, and the temperature is reduced to below 30°C for storage to obtain TPU beads, which are injection molded 2 mm test piece, the test results are shown in Table 2.

[0154] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: the TPU beads provided in this comparative example are extruded into a 10 mm thick plate through a screw extruder, the plate is placed in a foaming kettle, 5 MPa of carbon dioxide and 15 MPa of nitrogen are filled, then the temperature is raised to 145° C., the pressure is maintained at 20 MPa for foaming for 3 h, the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmosphere, and a foamed TPU plate is obtained, the performance evaluation data of which are shown in Table 1.

[0155] Comparative Example 2B

[0156] A polyurethane foam material and a preparation method thereof. The preparation method is as follows: using the TPU beads provided in Comparative Example 2A, a polyurethane foam material is prepared according to the same method as Example 5, and the performance evaluation data thereof is shown in Table 1.

[0157] Comparative Example 3A

[0158] A thermoplastic polyurethane elastomer and a preparation method thereof. The preparation method is as follows: by weight, 1 part of PTMEG-1000, 0.274 parts of HDI, 0.059 parts of 1,4-butanediol, 0.0001 parts of triethylamine and 0.005 parts of antioxidant 1010 are transported to a pouring system through a gear pump and mixed evenly to obtain a mixture; the mixture is poured on a twin-screw extruder for continuous reaction to synthesize a thermoplastic polyurethane elastomer, the temperatures of zones 1-10 of the twin-screw extruder are 120°C, 150°C, 155°C, 160°C, 160°C, 190°C, 190°C, 190°C, 210°C, 210°C, the die temperature is 210°C, the screw speed is 190 rpm, the obtained thermoplastic polyurethane elastomer is cooled and pelletized, and the temperature is reduced to below 30°C for storage to obtain TPU beads, which are injection molded 2 mm test piece, the test results are shown in Table 2.

[0159] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: the TPU beads provided in the comparative example are extruded into a 15 mm thick plate through a screw extruder, the plate is placed in a foaming kettle, 5 MPa of carbon dioxide and 15 MPa of nitrogen are filled, the temperature is raised to 115° C., the pressure is maintained at 20 MPa, constant temperature and pressure foaming is performed for 1.75 h, and then the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmosphere to obtain a TPU foam plate, the performance evaluation data of which are shown in Table 1.

[0160] Comparative Example 3B

[0161] A polyurethane foam material and a preparation method thereof. The preparation method is as follows: using the TPU beads provided in Comparative Example 3A, a polyurethane foam material is prepared according to the same method as Example 2, and the performance evaluation data thereof is shown in Table 1.

[0162] Comparative Example 4A

[0163] A thermoplastic polyurethane elastomer and a preparation method thereof. The preparation method is as follows: by weight, 1 part of PCDL-1500, 0.609 parts of HDI, 0.277 parts of 1,4-butanediol, 0.0007 parts of triethylamine and 0.005 parts of antioxidant 1010 are transported to a pouring system through a gear pump and mixed evenly to obtain a mixture; the mixture is poured on a twin-screw extruder for continuous reaction to synthesize a thermoplastic polyurethane elastomer, the temperatures of zones 1-10 of the twin-screw extruder are respectively: 120°C, 150°C, 155°C, 160°C, 160°C, 190°C, 190°C, 190°C, 220°C, 220°C, the head temperature is 240°C, the screw speed is 190 rpm, the obtained thermoplastic polyurethane elastomer is cooled and pelletized, and the temperature is reduced to below 30°C for storage to obtain TPU beads, which are injection molded 2 mm test piece, the test results are shown in Table 1.

[0164] A polyurethane foam material and a preparation method thereof, the preparation method being as follows: the TPU beads provided in this comparative example are extruded into a 10 mm thick plate through a screw extruder, the plate is placed in a foaming kettle, 5 MPa of carbon dioxide and 15 MPa of nitrogen are filled, then the temperature is raised to 145° C., the pressure is maintained at 20 MPa for foaming for 3 h, the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmosphere, and a foamed TPU plate is obtained, the performance evaluation data of which are shown in Table 1.

[0165] Comparative Example 4B

[0166] A polyurethane foam material and a preparation method thereof. The preparation method is as follows: using the TPU beads provided in Comparative Example 4A, a polyurethane foam material is prepared according to the same method as Example 5, and the performance evaluation data thereof is shown in Table 1.

[0167] Table 1

[0168]

[0169] Combined with the data in Table 1, it can be seen that the complex viscosity of the TPU elastomer provided by the present invention at 160°C and 0.01 Hz is 300-100000 Pa·s, and G' / G'' is 0.01-100, which makes it have excellent foaming performance. The polyurethane foam material obtained by foaming has a high foaming ratio, low density, uniform pores, uniform and controllable crust thickness, uniform and stable pore size, low shrinkage rate, high rebound performance and excellent mechanical properties; wherein the density of the polyurethane foam material of Examples 1-7 is 0.06-0.12 g / cm 3 The ball rebound rate is 78-82%, the shrinkage rate is 0.8-1.5%, and the crust thickness is 20-50 μm. It is a foaming material with excellent comprehensive performance.

[0170] Comparing Examples 1-7 with Examples 8-10, it can be seen that the present invention can further optimize the performance of the foam material through the temperature, pressure relief and aging process and parameter design of the two-stage foaming process, and obtain a polyurethane foam material with low density, low shrinkage, uniform and controllable crust thickness, and high resilience. In Examples 8-9, a one-stage foaming process was used, resulting in imperfect foaming and a slightly thick crust thickness; in Example 10, no aging was performed, resulting in imperfect foaming and large shrinkage.

[0171] The complex viscosity and G' / G'' of the TPU elastomer in Comparative Examples 1A-2B are not within the range defined by the present invention, resulting in poor foaming performance. Regardless of whether the conventional foaming process (Comparative Examples 1A and 2A) or the preferred two-stage foaming and aging process of the present invention (Comparative Examples 1B and 2B) is adopted, the resilience of the obtained foam material is small. The thickness of the foamed crust obtained in 1A-1B is too small, which is not conducive to surface treatment; the crust of 2A-2B is too thick, which is not conducive to the foaming ratio.

[0172] In Comparative Examples 3A-4B, only one of the complex viscosity and G' / G'' of the TPU elastomer is within the specified range of the present invention, and its foaming performance is still poor. The obtained foam material has small rebound, large shrinkage, and the crust thickness is not in the optimal range.

[0173] The applicant declares that the present invention uses the above embodiments to illustrate the thermoplastic polyurethane elastomer, polyurethane foam material and the preparation method and application thereof, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A thermoplastic polyurethane elastomer, characterized in that: The thermoplastic polyurethane elastomer has a complex viscosity of 300-100000 Pa·s at 160° C. and 0.01 Hz; The storage modulus of the thermoplastic polyurethane elastomer at 160° C. and 1 Hz is recorded as G', and the loss modulus is recorded as G'', and 0.01≤G' / G''≤100.

2. The thermoplastic polyurethane elastomer according to claim 1, characterized in that The thermoplastic polyurethane elastomer has a complex viscosity of 300-50000 Pa·s at 160° C. and 0.01 Hz; And / or, the storage modulus of the thermoplastic polyurethane elastomer at 160° C. and 1 Hz is denoted as G', and the loss modulus is denoted as G'', and 0.01≤G' / G''≤1.

3. The thermoplastic polyurethane elastomer according to claim 1 or 2, characterized in that: The thermoplastic polyurethane elastomer is obtained by reacting isocyanate, polyol and optionally a chain extender; The isocyanate includes any one of hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, dicyclohexylmethane diisocyanate, and hydrogenated xylylene diisocyanate, or a combination of at least two thereof; The polyol includes any one of polycarboxylate polyol, polyether polyol, polycarbonate polyol, and polycaprolactone polyol, or a combination of at least two thereof; The chain extender includes any one of ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, cyclohexanedimethanol, dihydroxyethylbenzene ether, propylene diamine, butylene diamine, p-phenylenediamine, biphenylenediamine, and 3,3'-dimethyl-4,4-biphenylenediamine, or a combination of at least two thereof.

4. The thermoplastic polyurethane elastomer according to claim 1 or 2, characterized in that: The thermoplastic polyurethane elastomer has a Shore hardness of 60A-70D.

5. A polyurethane foam material, characterized in that: The polyurethane foam material is obtained by foaming the thermoplastic polyurethane elastomer according to any one of claims 1 to 4.

6. A method for preparing a polyurethane foam material as claimed in claim 5, characterized in that: The preparation method comprises the following steps: The thermoplastic polyurethane elastomer according to any one of claims 1 to 4 is foamed under pressure using a physical foaming agent; after the foaming is completed, the pressure is released and the elastomer is aged to obtain the polyurethane foam material; The foaming includes a first stage of foaming and a second stage of foaming performed sequentially, the temperature of the first stage of foaming is recorded as T1, the temperature of the second stage of foaming is recorded as T2, 5°C≤T2-T1≤20°C; The aging temperature is denoted as T3, 0≤T3-T1≤20°C.

7. The preparation method according to claim 6, characterized in that: The physical foaming agent includes any one of nitrogen, carbon dioxide, methane, propane, butane, and pentane, or a combination of at least two thereof.

8. The preparation method according to claim 6, characterized in that: The foaming pressure is 10-65 MPa; The temperature of the first stage foaming is 100-160°C and the time is 0.1-24 h; The temperature of the second stage foaming is 105-180°C, and the time is 0.05-5 h.

9. The preparation method according to claim 6, characterized in that: The aging temperature is 100-180° C. and the aging time is 0.1-24 h.

10. Use of the polyurethane foam material as claimed in claim 5 in shoe materials, seat materials, tires, decorative materials, cushioning materials, thermal insulation materials, sound insulation materials, toys or sports equipment.

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