Modified polyurethane elastomer and application thereof in preparation of bimodal cellular structure foam

Abstract

The invention relates to a modified polyurethane elastomer and application of the modified polyurethane elastomer in preparation of bimodal cellular structure foam, and belongs to the technical field of foam forming. The invention provides a modified polyurethane elastomer. The modified polyurethane elastomer comprises the following components: a thermoplastic polyurethane elastomer, a polyisocyanate-based chain extender and an antioxidant component, in the modified polyurethane elastomer, the mass ratio of the thermoplastic polyurethane elastomer to the polyisocyanate chain extender to the antioxidant component is 1: (0.01-3): (0.05-1). According to the modified polyurethane elastomer, non-uniform chain extension modification is carried out on the thermoplastic polyurethane elastomer by introducing an insufficient amount of a polyisocyanate group chain extender, and the thermoplastic polyurethane elastomer foam obtained by foaming the modified polyurethane elastomer has a bimodal (big and small holes) foam structure; and the material has various excellent performances of light weight, heat insulation, sound insulation, buffering, high resilience and the like.

Description

Technical Field

[0001] The invention relates to a modified polyurethane elastomer and application thereof in preparing a bimodal cell structure foam, belonging to the technical field of foaming molding. Background Art

[0002] Bimodal cell structure foam is an advanced material with double bubble distribution, which contains both larger and smaller cells. This unique structural design makes the foam perform well in mechanical properties. The smaller cells enhance the foam's compression and shear resistance, while the larger cells provide more buffer space, improving the overall stability and impact resistance. In addition, the bimodal cell structure also effectively improves the foam's thermal insulation and sound absorption properties, and can significantly reduce heat conduction and noise transmission. At present, bimodal cell structure foam has been widely used in building insulation, automobile shock absorption, packaging protection and other fields, becoming an indispensable multifunctional material in modern industry.

[0003] At present, the preparation methods of common bimodal cell structure foams mainly include two-step pressure release method, crystal region regulation method, multiphase blending method and double foaming agent method, etc. For example, the patent application with publication number CN105419093A discloses a preparation method of bimodal cell structure foam, which belongs to multiphase blending method, by melt blending two polymers with different affinity to carbon dioxide, using the difference in solubility of the two polymers to supercritical carbon dioxide, resulting in significant difference in nucleation ability during foaming, thereby forming pores of different sizes in the two polymers, and finally making the pore structure of the foam material present a bimodal distribution; the patent application with publication number CN114702720A also discloses a preparation method of bimodal cell structure foam, which belongs to the crystal region regulation method, by annealing polybutene to form two different crystal forms inside, different crystal forms will show different melt strength at the same temperature, thereby leading to differences in foaming formation, and the difference in pore diameters of the pores in different crystal forms makes the foam material have a bimodal cell structure.

[0004] However, the above-mentioned preparation methods of bimodal cell structure foams all have certain limitations. For example, the above-mentioned preparation methods of bimodal cell structure foams all have complicated steps and are difficult to control, which makes it difficult to meet the actual production and application requirements. In addition, the above-mentioned preparation methods of bimodal cell structure foams all have difficulty in realizing the preparation of bimodal cell structure thermoplastic polyurethane elastomer (TPU) foam. Therefore, it is urgent to find a foaming method with simple steps and wide application range that can introduce a bimodal cell structure into a thermoplastic polyurethane elastomer to expand the application field of elastomer foam. Summary of the invention

[0005] In order to solve the above-mentioned defects, the present invention provides a modified polyurethane elastomer, the components of the modified polyurethane elastomer include a thermoplastic polyurethane elastomer, a polyisocyanate-based chain extender and an antioxidant component; in the modified polyurethane elastomer, the mass ratio of the thermoplastic polyurethane elastomer, the polyisocyanate-based chain extender and the antioxidant component is 1:0.01~3:0.05~1.

[0006] In one embodiment of the present invention, in the modified polyurethane elastomer, the mass ratio of the thermoplastic polyurethane elastomer, the polyisocyanate-based chain extender and the antioxidant component is 1:0.1 to 1:0.1 to 0.5.

[0007] In one embodiment of the present invention, the modified polyurethane elastomer is obtained by blending a thermoplastic polyurethane elastomer, a polyisocyanate-based chain extender and an antioxidant component.

[0008] In one embodiment of the present invention, the thermoplastic polyurethane elastomer (TPU) includes polyether TPU, polyester TPU, polyolefin TPU, aliphatic TPU and / or aromatic TPU.

[0009] In one embodiment of the present invention, the polyisocyanate-based chain extender includes toluene triisocyanate (TTI), triphenylmethane triisocyanate, triphenylmethane-4,4',4"-triisocyanate, DesmodurRE, DesmodurN100, aromatic methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI), hexamethylene diisocyanate (HDI) and / or isophorone diisocyanate (IPDI).

[0010] In one embodiment of the present invention, the antioxidant component includes antioxidant 1010, antioxidant 168, antioxidant 300 and / or antioxidant 626.

[0011] In one embodiment of the present invention, the antioxidant component consists of antioxidant 1010 and antioxidant 168; in the antioxidant component, the mass ratio of antioxidant 1010 to antioxidant 168 is 1:1-4.

[0012] In one embodiment of the present invention, in the antioxidant component, the mass ratio of antioxidant 1010 to antioxidant 168 is 1:2.

[0013] The present invention also provides a bimodal cell structure thermoplastic polyurethane elastomer foam, which is obtained by foaming the modified polyurethane elastomer.

[0014] In one embodiment of the present invention, the foaming is physical foaming or chemical foaming.

[0015] In one embodiment of the present invention, the physical foaming comprises: placing a foaming body made of a modified polyurethane elastomer in a high-pressure fluid for saturation, and then rapidly releasing pressure and foaming it or rapidly heating it to obtain a thermoplastic polyurethane elastomer foam with a bimodal cell structure.

[0016] In one embodiment of the present invention, the rapid pressure relief foaming includes: placing a foaming body whose material is a modified polyurethane elastomer in a foaming container whose internal temperature is a saturation temperature, and introducing a high-pressure fluid into the foaming container until the internal pressure of the foaming container reaches the saturation pressure; continuously placing the foaming body in a foaming container whose pressure is a saturation pressure and whose temperature is a saturation temperature until the high-pressure fluid reaches saturation in the foaming body; after reaching saturation, releasing the pressure in the foaming container to the ambient pressure at a pressure relief rate, inducing the nucleation and growth of the bubbles, so that the foaming body foams, and obtains a thermoplastic polyurethane elastomer foam with a bimodal pore structure.

[0017] In one embodiment of the present invention, in the rapid pressure relief foaming, the saturation temperature is (T m -50)℃~T m ℃, where T m It is the melting point of thermoplastic polyurethane elastomer.

[0018] In one embodiment of the present invention, in the rapid pressure relief foaming, the saturation temperature is (T m -30)℃~(T m -10)℃, where T m It is the melting point of thermoplastic polyurethane elastomer.

[0019] In one embodiment of the present invention, in the rapid pressure relief foaming, the saturation pressure is 3 MPa to 20 MPa.

[0020] In one embodiment of the present invention, in the rapid pressure relief foaming, the saturation pressure is 5 MPa to 20 MPa.

[0021] In one embodiment of the present invention, in the rapid pressure relief foaming, the pressure relief rate is 5 MPa / s to 100 MPa / s.

[0022] In one embodiment of the present invention, the rapid temperature rise foaming includes: placing a foaming body whose material is a modified polyurethane elastomer in a foaming container whose internal temperature is a saturation temperature, and passing a high-pressure fluid into the foaming container until the internal pressure of the foaming container reaches the saturation pressure; continuously placing the foaming body in a foaming container whose pressure is a saturation pressure and whose temperature is a saturation temperature until the high-pressure fluid reaches saturation in the foaming body; after reaching saturation, firstly releasing the pressure in the foaming container to the ambient pressure at a pressure relief rate to obtain a saturated foaming body, and then placing the saturated foaming body in a foaming container whose internal temperature is a foaming temperature to induce the nucleation and growth of the bubbles, so that the saturated foaming body foams to obtain a thermoplastic polyurethane elastomer foam with a bimodal cell structure.

[0023] In one embodiment of the present invention, during the rapid heating and foaming, the saturation temperature is 0°C to T v ℃, where T v is the Vicat softening temperature of thermoplastic polyurethane elastomer.

[0024] In one embodiment of the present invention, in the rapid temperature rise foaming, the saturation temperature is 20 to 50° C., wherein T v is the Vicat softening temperature of thermoplastic polyurethane elastomer.

[0025] In one embodiment of the present invention, during the rapid temperature rise foaming, the saturation pressure is 3 MPa to 10 MPa.

[0026] In one embodiment of the present invention, during the rapid temperature rise foaming, the saturation pressure is 5 MPa to 8 MPa.

[0027] In one embodiment of the present invention, during the rapid temperature rise foaming, the pressure release rate is 0.01 MPa / s to 1 MPa / s.

[0028] In one embodiment of the present invention, during the rapid heating foaming, the foaming temperature is T v ℃~T m ℃, where T v is the Vicat softening temperature of thermoplastic polyurethane elastomer, T m It is the melting point of thermoplastic polyurethane elastomer.

[0029] In one embodiment of the present invention, during the rapid heating and foaming, the foaming temperature is (T v +30)℃~(T m -10)℃, where T v is the Vicat softening temperature of thermoplastic polyurethane elastomer, T m It is the melting point of thermoplastic polyurethane elastomer.

[0030] In one embodiment of the present invention, in the rapid temperature rise foaming, the foaming time is 5 to 60 seconds.

[0031] In one embodiment of the present invention, the high-pressure fluid includes supercritical carbon dioxide and / or supercritical nitrogen.

[0032] In one embodiment of the present invention, the foaming container is an autoclave and / or an oil bath.

[0033] In one embodiment of the present invention, the method for preparing the foamed embryo body comprises: blending a thermoplastic polyurethane elastomer, a polyisocyanate-based chain extender and an antioxidant component and then molding the mixture to obtain a foamed embryo body.

[0034] In one embodiment of the present invention, the blending includes blending in a torque rheometer (ie, internal mixer), blending in a twin-screw extruder and / or solvent blending.

[0035] In one embodiment of the present invention, when blending in a torque rheometer, the torque speed of the torque rheometer is 60-100 rpm; when blending in a twin-screw extruder, the torque speed of the twin-screw extruder is 100-500 rpm.

[0036] In one embodiment of the present invention, when blending in a torque rheometer, the torque speed of the torque rheometer is 80-90 rpm; when blending in a twin-screw extruder, the torque speed of the twin-screw extruder is 150-450 rpm.

[0037] In one embodiment of the present invention, the blending time is to stop mixing when the torque value reaches a stable value.

[0038] In one embodiment of the present invention, the blending temperature is (T m +10)℃~(T m +40)℃.

[0039] In one embodiment of the present invention, the blending temperature is (T m +20)℃~(T m +30).

[0040] In one embodiment of the present invention, the molding includes injection molding, foaming molding, extrusion molding and / or compression molding.

[0041] In one embodiment of the present invention, the molding temperature is (T m +10)℃~(T m +40)℃.

[0042] In one embodiment of the present invention, the molding temperature is (Tm +20)℃~(T m +30).

[0043] In one embodiment of the present invention, the bimodal cell structure thermoplastic polyurethane elastomer foam has an elastomer foam density of 0.05 to 0.4 g / cm 3 .

[0044] In one embodiment of the present invention, in the bimodal pore structure thermoplastic polyurethane elastomer foam, the sizes of large pores and small pores differ by one order of magnitude, large pores account for 20% to 90%, the average pore size of large pores is 10 to 50 μm, and the average pore size of small pores is 0.5 to 10 μm.

[0045] In one embodiment of the present invention, in the bimodal cell structure thermoplastic polyurethane elastomer foam, the average cell size of the macropores is 15 to 30 μm, and the average cell size of the micropores is 1 to 5 μm.

[0046] The present invention also provides a method for preparing a bimodal cell structure thermoplastic polyurethane elastomer foam, the method comprising: foaming the modified polyurethane elastomer to obtain the bimodal cell structure thermoplastic polyurethane elastomer foam.

[0047] In one embodiment of the present invention, the foaming is physical foaming or chemical foaming.

[0048] In one embodiment of the present invention, the physical foaming comprises: placing a foaming body made of a modified polyurethane elastomer in a high-pressure fluid for saturation, and then rapidly releasing pressure and foaming it or rapidly heating it to obtain a thermoplastic polyurethane elastomer foam with a bimodal cell structure.

[0049] In one embodiment of the present invention, the rapid pressure relief foaming includes: placing a foaming body whose material is a modified polyurethane elastomer in a foaming container whose internal temperature is a saturation temperature, and introducing a high-pressure fluid into the foaming container until the internal pressure of the foaming container reaches the saturation pressure; continuously placing the foaming body in a foaming container whose pressure is a saturation pressure and whose temperature is a saturation temperature until the high-pressure fluid reaches saturation in the foaming body; after reaching saturation, releasing the pressure in the foaming container to the ambient pressure at a pressure relief rate, inducing the nucleation and growth of the bubbles, so that the foaming body foams, and obtains a thermoplastic polyurethane elastomer foam with a bimodal pore structure.

[0050] In one embodiment of the present invention, in the rapid pressure relief foaming, the saturation temperature is (T m -50)℃~T m ℃, where T m It is the melting point of thermoplastic polyurethane elastomer.

[0051] In one embodiment of the present invention, in the rapid pressure relief foaming, the saturation temperature is (T m -30)℃~(T m -10)℃, where T m It is the melting point of thermoplastic polyurethane elastomer.

[0052] In one embodiment of the present invention, in the rapid pressure relief foaming, the saturation pressure is 3 MPa to 20 MPa.

[0053] In one embodiment of the present invention, in the rapid pressure relief foaming, the saturation pressure is 5 MPa to 20 MPa.

[0054] In one embodiment of the present invention, in the rapid pressure relief foaming, the pressure relief rate is 5 MPa / s to 100 MPa / s.

[0055] In one embodiment of the present invention, the rapid temperature rise foaming includes: placing a foaming body whose material is a modified polyurethane elastomer in a foaming container whose internal temperature is a saturation temperature, and passing a high-pressure fluid into the foaming container until the internal pressure of the foaming container reaches the saturation pressure; continuously placing the foaming body in a foaming container whose pressure is a saturation pressure and whose temperature is a saturation temperature until the high-pressure fluid reaches saturation in the foaming body; after reaching saturation, firstly releasing the pressure in the foaming container to the ambient pressure at a pressure relief rate to obtain a saturated foaming body, and then placing the saturated foaming body in a foaming container whose internal temperature is a foaming temperature to induce the nucleation and growth of the bubbles, so that the saturated foaming body foams to obtain a thermoplastic polyurethane elastomer foam with a bimodal cell structure.

[0056] In one embodiment of the present invention, during the rapid heating and foaming, the saturation temperature is 0°C to T v ℃, where T v is the Vicat softening temperature of thermoplastic polyurethane elastomer.

[0057] In one embodiment of the present invention, in the rapid temperature rise foaming, the saturation temperature is 20 to 50°C, wherein T v is the Vicat softening temperature of thermoplastic polyurethane elastomer.

[0058] In one embodiment of the present invention, during the rapid temperature rise foaming, the saturation pressure is 3 MPa to 10 MPa.

[0059] In one embodiment of the present invention, during the rapid temperature rise foaming, the saturation pressure is 5 MPa to 8 MPa.

[0060] In one embodiment of the present invention, during rapid temperature rise foaming, the pressure release rate is 0.01 MPa / s to 1 MPa / s.

[0061] In one embodiment of the present invention, during the rapid heating foaming, the foaming temperature is T v ℃~T m ℃, where T v is the Vicat softening temperature of thermoplastic polyurethane elastomer, T m It is the melting point of thermoplastic polyurethane elastomer.

[0062] In one embodiment of the present invention, during the rapid heating and foaming, the foaming temperature is (T v +30)℃~(T m -10)℃, where T v is the Vicat softening temperature of thermoplastic polyurethane elastomer, T m It is the melting point of thermoplastic polyurethane elastomer.

[0063] In one embodiment of the present invention, in the rapid temperature rise foaming, the foaming time is 5 to 60 seconds.

[0064] In one embodiment of the present invention, the high-pressure fluid includes supercritical carbon dioxide and / or supercritical nitrogen.

[0065] In one embodiment of the present invention, the foaming container is an autoclave and / or an oil bath.

[0066] In one embodiment of the present invention, the method for preparing the foamed embryo body comprises: blending a thermoplastic polyurethane elastomer, a polyisocyanate-based chain extender and an antioxidant component and then molding the mixture to obtain a foamed embryo body.

[0067] In one embodiment of the present invention, the blending includes blending in a torque rheometer, blending in a twin-screw extruder and / or solvent blending.

[0068] In one embodiment of the present invention, when blending in a torque rheometer, the torque speed of the torque rheometer is 60-100 rpm; when blending in a twin-screw extruder, the torque speed of the twin-screw extruder is 100-500 rpm.

[0069] In one embodiment of the present invention, when blending in a torque rheometer, the torque speed of the torque rheometer is 80-90 rpm; when blending in a twin-screw extruder, the torque speed of the twin-screw extruder is 150-450 rpm.

[0070] In one embodiment of the present invention, the blending time is to stop mixing when the torque value reaches a stable value.

[0071] In one embodiment of the present invention, the blending temperature is (T m +10)℃~(Tm +40)℃.

[0072] In one embodiment of the present invention, the blending temperature is (T m +20)℃~(T m +30).

[0073] In one embodiment of the present invention, the molding includes injection molding, foaming molding, extrusion molding and / or compression molding.

[0074] In one embodiment of the present invention, the molding temperature is (T m +10)℃~(T m +40)℃.

[0075] In one embodiment of the present invention, the molding temperature is (T m +20)℃~(T m +30).

[0076] In one embodiment of the present invention, the bimodal cell structure thermoplastic polyurethane elastomer foam has an elastomer foam density of 0.05 to 0.4 g / cm 3 .

[0077] In one embodiment of the present invention, in the bimodal pore structure thermoplastic polyurethane elastomer foam, the sizes of large pores and small pores differ by one order of magnitude, large pores account for 20% to 90%, the average pore size of large pores is 10 to 50 μm, and the average pore size of small pores is 0.5 to 10 μm.

[0078] In one embodiment of the present invention, in the bimodal cell structure thermoplastic polyurethane elastomer foam, the average cell size of the macropores is 15 to 30 μm, and the average cell size of the micropores is 1 to 5 μm.

[0079] The present invention also provides the use of the modified polyurethane elastomer or the bimodal pore structure thermoplastic polyurethane elastomer foam in the preparation of thermal insulation products, buffering and rebound products and / or sound insulation products.

[0080] The technical solution of the present invention has the following advantages:

[0081] 1. The present invention provides a modified polyurethane elastomer, wherein the modified polyurethane elastomer comprises a thermoplastic polyurethane elastomer, a polyisocyanate-based chain extender and an antioxidant component; in the modified polyurethane elastomer, the mass ratio of the thermoplastic polyurethane elastomer, the polyisocyanate-based chain extender and the antioxidant component is 1:0.01-3:0.05-1. The modified polyurethane elastomer is modified by introducing an insufficient amount of polyisocyanate-based chain extender to perform uneven chain extension modification on the thermoplastic polyurethane elastomer, wherein the chain-extended modified thermoplastic polyurethane elastomer has a high degree of cross-linking and the melt strength of the matrix is ​​significantly enhanced. During the foaming process, on the one hand, the cells cannot be biaxially stretched during the growth process, thereby hindering the growth, and on the other hand, the cells are not easy to coalesce or rupture, resulting in a smaller cell size. The molecular chains of the thermoplastic polyurethane elastomer that has not been modified by chain extension are relatively regular. During the foaming process, the cells are easy to grow and coalesce, resulting in a larger cell size. Therefore, the thermoplastic polyurethane elastomer foam obtained by foaming the modified polyurethane elastomer has a bimodal (large and small pores) cell structure, and has many excellent properties such as light weight, heat insulation, sound insulation, cushioning, high resilience, etc. At the same time, the thermoplastic polyurethane elastomer foam obtained by foaming the modified polyurethane elastomer has a higher expansion ratio than the thermoplastic polyurethane elastomer foam obtained by foaming the unmodified thermoplastic polyurethane elastomer, and the morphology and proportion of the bimodal cells can be adjusted to control the distribution of cells at all levels. In addition, the foaming process of the modified polyurethane elastomer is simple, the process is green and safe, and the cost is low, and it has the potential value of large-scale industrial application.

[0082] 2. A method for preparing a bimodal cellular structure thermoplastic polyurethane elastomer foam, the method comprising: foaming a modified polyurethane elastomer to obtain a bimodal cellular structure thermoplastic polyurethane elastomer foam; the modified polyurethane elastomer comprises a thermoplastic polyurethane elastomer, a polyisocyanate-based chain extender and an antioxidant component; in the modified polyurethane elastomer, the mass ratio of the thermoplastic polyurethane elastomer, the polyisocyanate-based chain extender and the antioxidant component is 1:0.01~3:0.05~1. The modified polyurethane elastomer used in the method is modified by introducing an insufficient amount of polyisocyanate-based chain extender to perform uneven chain extension modification on the thermoplastic polyurethane elastomer, wherein the chain-extended modified thermoplastic polyurethane elastomer has a high degree of crosslinking and the melt strength of the matrix is ​​significantly enhanced. During the foaming process, on the one hand, the cells cannot be biaxially stretched during the growth process, thereby hindering the growth; on the other hand, the cells are not easy to coalesce or rupture, resulting in a smaller cell size, while the molecular chains of the thermoplastic polyurethane elastomer that has not been modified by chain extension are relatively regular, and during the foaming process, the cells are easy to grow and coalesce, resulting in a larger cell size. Therefore, the thermoplastic polyurethane elastomer foam prepared by the method has a bimodal (large and small pores) cell structure, and has many excellent properties such as light weight, heat insulation, sound insulation, cushioning, high resilience, etc. At the same time, the thermoplastic polyurethane elastomer foam obtained by foaming the modified polyurethane elastomer has a higher expansion ratio than the thermoplastic polyurethane elastomer foam obtained by foaming the unmodified thermoplastic polyurethane elastomer, and the morphology and proportion of the bimodal cells can be adjusted to control the distribution of cells at each level. In addition, the foaming process of preparing thermoplastic polyurethane elastomer foam using modified polyurethane elastomer is simple, the process is green and safe, and the cost is low, which has the potential value of large-scale industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Figure 1 : Schematic diagram of TPU reaction branching principle.

[0084] Figure 2 : Schematic diagram of the foaming effect of TPU with different branching degrees.

[0085] Figure 3 : The cell structure of the TPU foam prepared in Example 2-1.

[0086] Figure 4 : The pore structure of the TPU foam prepared in Comparative Example 2-1.

[0087] Figure 5 : The pore structure of the TPU foam prepared in Comparative Example 2-2. DETAILED DESCRIPTION

[0088] The following examples are provided for a better understanding of the present invention, but are not intended to limit the best mode of implementation, nor to limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained by anyone under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0089] If no specific experimental steps or conditions are specified in the following examples, the conventional experimental steps or conditions described in the literature in the field can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be purchased commercially.

[0090] Example 1-1: A modified polyurethane elastomer

[0091] This embodiment provides a modified polyurethane elastomer, which is composed of 100 parts of TPU (polyether type, hardness of 80A, Vicat softening temperature of 90°C, melting point of 150°C, purchased from BASF), 0.5 parts of toluene triisocyanate (polyisocyanate-based chain extender) and 0.5 parts of antioxidant component; wherein the antioxidant component is obtained by compounding antioxidant 1010 and antioxidant 168 in a mass ratio of 1:2;

[0092] The preparation method of the modified polyurethane elastomer is as follows: TPU, toluene triisocyanate and an antioxidant component are placed in an internal mixer and blended at 170° C.; blending is stopped when the torque value of the internal mixer tends to be stable, thereby obtaining the modified polyurethane elastomer.

[0093] Example 1-2: A modified polyurethane elastomer

[0094] This embodiment provides a modified polyurethane elastomer. The modified polyurethane elastomer is obtained by replacing toluene triisocyanate with triphenylmethane triisocyanate (polyisocyanate-based chain extender) on the basis of Embodiment 1-1.

[0095] Example 1-3: A modified polyurethane elastomer

[0096] This embodiment provides a modified polyurethane elastomer. The modified polyurethane elastomer is obtained by replacing the amount of toluene triisocyanate (polyisocyanate-based chain extender) in Embodiment 1-1 with 0.2 parts instead of 0.5 parts.

[0097] Example 1-4: A modified polyurethane elastomer

[0098] This embodiment provides a modified polyurethane elastomer. The modified polyurethane elastomer is obtained by replacing the amount of the antioxidant component in Embodiment 1-1 from 0.5 parts to 0.2 parts.

[0099] Example 1-5: A modified polyurethane elastomer

[0100] This embodiment provides a modified polyurethane elastomer. The modified polyurethane elastomer is obtained by replacing the antioxidant component of the compound of antioxidant 1010 and antioxidant 168 in a mass ratio of 1:2 with a single antioxidant 300 on the basis of Embodiment 1-1.

[0101] Example 1-6: A modified polyurethane elastomer

[0102] This embodiment provides a modified polyurethane elastomer. The modified polyurethane elastomer is obtained by replacing the type of TPU from polyether type to polyester type on the basis of Embodiment 1-1.

[0103] Example 2-1: A method for preparing a thermoplastic polyurethane elastomer foam having a bimodal cell structure

[0104] The present embodiment provides a method for preparing a thermoplastic polyurethane elastomer foam with a bimodal cell structure, the method comprising: placing the modified polyurethane elastomer of Example 1-1 in a hot press, and hot pressing and molding at 170° C. to obtain a block-shaped foamed embryo (size 100 mm×100 mm×10 mm); placing the foamed embryo in an autoclave with an internal temperature of 140° C. (saturation temperature), and introducing supercritical carbon dioxide into the autoclave until the internal pressure of the autoclave reaches 15 MPa (saturation pressure); continuously placing the foamed embryo in an autoclave with a pressure of 15 MPa and a temperature of 140° C. until the carbon dioxide reaches saturation in the foamed embryo; after reaching saturation (taking 30 min), the pressure in the autoclave is released to ambient pressure at a pressure release rate of 50 MPa / s to induce nucleation and growth of cells, so that the foamed embryo foams to obtain a bimodal cell structure thermoplastic polyurethane elastomer foam (TPU reaction branching principle see Figure 1 The foaming effect of TPU with different branching degrees is shown in Figure 2 ).

[0105] Example 2-2: A method for preparing a thermoplastic polyurethane elastomer foam having a bimodal cell structure

[0106] This embodiment provides a method for preparing a bimodal pore structured thermoplastic polyurethane elastomer foam. The method is as follows: on the basis of Embodiment 2-1, the modified polyurethane elastomer of Embodiment 1-1 is replaced by the modified polyurethane elastomer of Embodiment 1-2 to obtain a bimodal pore structured thermoplastic polyurethane elastomer foam.

[0107] Example 2-3: A method for preparing a bimodal cell structure thermoplastic polyurethane elastomer foam

[0108] This embodiment provides a method for preparing a bimodal cellular structured thermoplastic polyurethane elastomer foam. The method is as follows: on the basis of Embodiment 2-1, the modified polyurethane elastomer of Embodiment 1-1 is replaced with the modified polyurethane elastomer of Embodiment 1-3 to obtain a bimodal cellular structured thermoplastic polyurethane elastomer foam.

[0109] Example 2-4: A method for preparing a bimodal cell structure thermoplastic polyurethane elastomer foam

[0110] This embodiment provides a method for preparing a bimodal pore structured thermoplastic polyurethane elastomer foam. The method is as follows: on the basis of Embodiment 2-1, the modified polyurethane elastomer of Embodiment 1-1 is replaced with the modified polyurethane elastomer of Embodiment 1-4 to obtain a bimodal pore structured thermoplastic polyurethane elastomer foam.

[0111] Example 2-5: A method for preparing a bimodal cell structure thermoplastic polyurethane elastomer foam

[0112] This embodiment provides a method for preparing a bimodal pore structured thermoplastic polyurethane elastomer foam. The method is as follows: on the basis of Embodiment 2-1, the modified polyurethane elastomer of Embodiment 1-1 is replaced with the modified polyurethane elastomer of Embodiment 1-5 to obtain a bimodal pore structured thermoplastic polyurethane elastomer foam.

[0113] Example 2-6: A method for preparing a bimodal cell structure thermoplastic polyurethane elastomer foam

[0114] This embodiment provides a method for preparing a bimodal pore structured thermoplastic polyurethane elastomer foam. The method is as follows: on the basis of Embodiment 2-1, the modified polyurethane elastomer of Embodiment 1-1 is replaced with the modified polyurethane elastomer of Embodiment 1-6 to obtain a bimodal pore structured thermoplastic polyurethane elastomer foam.

[0115] Example 2-7: A method for preparing a thermoplastic polyurethane elastomer foam with a bimodal cell structure

[0116] This embodiment provides a method for preparing a bimodal cellular structure thermoplastic polyurethane elastomer foam. The method is as follows: based on Example 2-1, the saturation temperature is replaced from 140° C. to 120° C. to obtain a bimodal cellular structure thermoplastic polyurethane elastomer foam.

[0117] Example 2-8: A method for preparing a thermoplastic polyurethane elastomer foam having a bimodal cell structure

[0118] This embodiment provides a method for preparing a bimodal cellular structure thermoplastic polyurethane elastomer foam. The method is as follows: on the basis of Example 2-1, the saturation pressure is replaced from 15 MPa to 10 MPa to obtain a bimodal cellular structure thermoplastic polyurethane elastomer foam.

[0119] Example 2-9: A method for preparing a bimodal cell structure thermoplastic polyurethane elastomer foam

[0120] The present embodiment provides a method for preparing a bimodal cellular structure thermoplastic polyurethane elastomer foam, the method comprising: placing the modified polyurethane elastomer of Example 1-1 in a hot press, and hot pressing and molding at 170° C. to obtain a block-shaped foamed embryo; placing the foamed embryo in an autoclave with an internal temperature of 25° C. (saturation temperature), and introducing supercritical carbon dioxide into the autoclave until the internal pressure of the autoclave reaches 5 MPa (saturation pressure); continuously placing the foamed embryo in a pressure of 5 MPa , in an autoclave at a temperature of 25°C until the carbon dioxide reaches saturation in the foaming embryo; after reaching saturation (taking 24 hours), the pressure in the autoclave is first released to ambient pressure at a pressure relief rate of 0.5 MPa / s to obtain a saturated foaming embryo, and then the foaming embryo is taken out of the autoclave, and placed in an oil bath pot at 140°C (foaming temperature) to induce the nucleation and growth of the bubbles, so that the foaming embryo is heated and foamed (taking 60 seconds) to obtain a bimodal pore structure thermoplastic polyurethane elastomer foam.

[0121] Example 2-10: A method for preparing a bimodal cell structure thermoplastic polyurethane elastomer foam

[0122] This embodiment provides a method for preparing a bimodal cellular structure thermoplastic polyurethane elastomer foam. The method is as follows: on the basis of Embodiment 2-9, the saturation pressure is replaced from 5 MPa to 8 MPa to obtain a bimodal cellular structure thermoplastic polyurethane elastomer foam.

[0123] Example 2-11: A method for preparing a bimodal cell structure thermoplastic polyurethane elastomer foam

[0124] This embodiment provides a method for preparing a bimodal cellular structure thermoplastic polyurethane elastomer foam. The method is as follows: based on Embodiment 2-9, the foaming temperature is replaced from 140° C. to 130° C. to obtain a bimodal cellular structure thermoplastic polyurethane elastomer foam.

[0125] Comparative Example 1-1: A modified polyurethane elastomer

[0126] This comparative example provides a modified polyurethane elastomer. The modified polyurethane elastomer is obtained by not adding a polyisocyanate-based chain extender on the basis of Example 1-1.

[0127] Comparative Example 1-2: A modified polyurethane elastomer

[0128] This comparative example provides a modified polyurethane elastomer. The modified polyurethane elastomer is obtained by replacing the amount of toluene triisocyanate (polyisocyanate-based chain extender) in Example 1-1 with 5 parts instead of 0.5 parts.

[0129] Comparative Example 1-3: A modified polyurethane elastomer

[0130] This comparative example provides a modified polyurethane elastomer. The modified polyurethane elastomer is obtained by not adding an antioxidant component based on Example 1-1.

[0131] Comparative Example 2-1: A method for preparing thermoplastic polyurethane elastomer foam

[0132] This comparative example provides a method for preparing a thermoplastic polyurethane elastomer foam. The method is as follows: on the basis of Example 2-1, the modified polyurethane elastomer of Example 1-1 is replaced by the modified polyurethane elastomer of Comparative Example 1-1 to obtain a thermoplastic polyurethane elastomer foam.

[0133] Comparative Example 2-2: A method for preparing thermoplastic polyurethane elastomer foam

[0134] This comparative example provides a method for preparing a thermoplastic polyurethane elastomer foam. The method is as follows: on the basis of Example 2-1, the modified polyurethane elastomer of Example 1-1 is replaced by the modified polyurethane elastomer of Comparative Example 1-2 to obtain a thermoplastic polyurethane elastomer foam.

[0135] Comparative Example 2-3: A method for preparing thermoplastic polyurethane elastomer foam

[0136] This comparative example provides a method for preparing a thermoplastic polyurethane elastomer foam. The method is as follows: on the basis of Example 2-1, the modified polyurethane elastomer of Example 1-1 is replaced by the modified polyurethane elastomer of Comparative Example 1-3 to obtain a thermoplastic polyurethane elastomer foam.

[0137] Comparative Example 2-4: A method for preparing thermoplastic polyurethane elastomer foam

[0138] This comparative example provides a method for preparing a thermoplastic polyurethane elastomer foam. The method is based on Example 2-1, except that the saturation temperature is replaced from 140° C. to 90° C.

[0139] Comparative Example 2-5: A method for preparing thermoplastic polyurethane elastomer foam

[0140] This comparative example provides a method for preparing a thermoplastic polyurethane elastomer foam. The method is based on Example 2-1, but the saturation temperature is replaced from 140°C to 160°C.

[0141] Comparative Example 2-6: A method for preparing thermoplastic polyurethane elastomer foam

[0142] This comparative example provides a method for preparing a thermoplastic polyurethane elastomer foam. The method is based on Example 2-1, except that the saturation pressure is replaced from 15 MPa to 3 MPa.

[0143] Comparative Example 2-7: A method for preparing thermoplastic polyurethane elastomer foam

[0144] This comparative example provides a method for preparing a thermoplastic polyurethane elastomer foam. The method is based on Example 2-9, but the saturation pressure is replaced by 2 MPa from 5 MPa.

[0145] Comparative Example 2-8: A method for preparing thermoplastic polyurethane elastomer foam

[0146] This comparative example provides a method for preparing thermoplastic polyurethane elastomer foam. The method is based on Example 2-9, but the foaming temperature is replaced from 140°C to 90°C.

[0147] Comparative Example 2-9: A method for preparing thermoplastic polyurethane elastomer foam

[0148] This comparative example provides a method for preparing thermoplastic polyurethane elastomer foam. The method is based on Example 2-9, but the foaming temperature is replaced from 140°C to 160°C.

[0149] Experimental Example 1: Performance Verification of Thermoplastic Polyurethane Elastomer Foam

[0150] This experimental example verifies the performance of the thermoplastic polyurethane elastomer foams of Examples 2-1 to 2-11 and Comparative Examples 2-1 to 2-9, and the verification process is as follows:

[0151] The foam density of the thermoplastic polyurethane elastomer foam of Examples 2-1 to 2-11 and Comparative Examples 2-1 to 2-9 was measured using an analytical balance with a density assembly, and the foam density was calculated according to the formula VER = ρ0 / ρ f (where ρ0 is the initial density of TPU, ρ f The foam density of TPU after foaming was calculated, and the foaming ratio was calculated. The results are shown in Table 1. The thermoplastic polyurethane elastomer foams of Examples 2-1 to 2-11 and Comparative Examples 2-1 to 2-9 were quenched by liquid nitrogen, and gold was sprayed on the cross section. The obtained polymer foams were analyzed by SEM. The results are shown in Table 1 and Figure 3 to Figure 5 shown.

[0152] From Table 1 and Figure 3 to Figure 5 As shown, the polymer foam manufactured by the method of Example 2-1 to Example 2-11 not only satisfies the requirement of having a bimodal pore structure, but also the expansion ratio of the foam is significantly improved. In Comparative Example 2-1, no polyisocyanate chain extender is added, the TPU molecular chains are all straight chain structures, the matrix melt strength is low and the pores are easy to aggregate, the foam expansion ratio is low and the pores are all large pore structures. In Comparative Example 2-2, an excessive amount of polyisocyanate chain extender is added, TPU and polyisocyanate chain extender react completely, TPU molecular chains are all branched cross-linked structures, the matrix melt strength is high, and the pores are all small pore structures. In Comparative Example 2-3, no antioxidant is added, TPU is partially degraded during processing, and the expansion ratio of the foam is low. In Comparative Example 2-4, the saturation temperature is low, the TPU molecular chain has weak mobility at the foaming temperature, and foaming cannot be achieved. In Comparative Example 2-5, the saturation temperature is high, and TPU is in a molten state at the foaming temperature, and foaming cannot be achieved. In Comparative Example 2-6, the saturation pressure is low, and the solubility of TPU is too low at this pressure, so foaming cannot be achieved. In Comparative Example 2-7, the saturation pressure is low, and the solubility of TPU is too low at this pressure, so foaming cannot be achieved. In Comparative Example 2-8, the foaming temperature is low, and the mobility of TPU molecular chains is weak at the foaming temperature, so foaming cannot be achieved. In Comparative Example 2-9, the foaming temperature is high, and TPU is in a molten state at the foaming temperature, so foaming cannot be achieved.

[0153] Table 1 Foam density and SEM analysis results of thermoplastic polyurethane elastomer foam

[0154]

[0155]

[0156] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A modified polyurethane elastomer, characterized in that: The modified polyurethane elastomer comprises thermoplastic polyurethane elastomer, polyisocyanate-based chain extender and antioxidant component; in the modified polyurethane elastomer, the mass ratio of thermoplastic polyurethane elastomer, polyisocyanate-based chain extender and antioxidant component is 1:0.01-3:0.05-1.

2. The modified polyurethane elastomer according to claim 1, characterized in that In the modified polyurethane elastomer, the mass ratio of the thermoplastic polyurethane elastomer, the polyisocyanate-based chain extender and the antioxidant component is 1:0.1 to 1:0.1 to 0.

5.

3. The modified polyurethane elastomer according to claim 1 or 2, characterized in that: The thermoplastic polyurethane elastomer includes polyether TPU, polyester TPU, polyolefin TPU, aliphatic TPU and / or aromatic TPU.

4. The modified polyurethane elastomer according to any one of claims 1 to 3, characterized in that The polyisocyanate-based chain extender includes toluene triisocyanate, triphenylmethane triisocyanate, triphenylmethane-4,4',4"-triisocyanate, Desmodur RE, Desmodur N100, aromatic methylene diphenyl diisocyanate, toluene diisocyanate, hexamethylene diisocyanate and / or isophorone diisocyanate.

5. The modified polyurethane elastomer according to any one of claims 1 to 4, characterized in that The antioxidant component includes antioxidant 1010 , antioxidant 168 , antioxidant 300 and / or antioxidant 626 .

6. A bimodal cell structure thermoplastic polyurethane elastomer foam, characterized in that: The bimodal cellular structure thermoplastic polyurethane elastomer foam is obtained by foaming the modified polyurethane elastomer described in any one of claims 1 to 5.

7. The bimodal cell structured thermoplastic polyurethane elastomer foam according to claim 6, characterized in that: The foaming is physical foaming or chemical foaming.

8. The bimodal cell structured thermoplastic polyurethane elastomer foam according to claim 7, characterized in that: The physical foaming comprises: placing a foaming embryonic body whose material is a modified polyurethane elastomer in a high-pressure fluid for saturation, and then rapidly releasing pressure and foaming or rapidly heating and foaming to obtain a thermoplastic polyurethane elastomer foam with a bimodal cell structure.

9. A method for preparing a bimodal cell structure thermoplastic polyurethane elastomer foam, characterized in that: The method comprises: foaming the modified polyurethane elastomer according to any one of claims 1 to 5 to obtain a thermoplastic polyurethane elastomer foam with a bimodal cell structure.

10. Use of the modified polyurethane elastomer according to any one of claims 1 to 5 or the bimodal cellular structure thermoplastic polyurethane elastomer foam according to claim 6 in the preparation of thermal insulation products, buffer rebound products and / or sound insulation products.

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