A low-shrinkage nylon elastomer foaming material, its preparation method and application

Abstract

The present invention provides a low-shrinkage nylon elastomer foaming material, its preparation method and application. The shrinkage rate of the low-shrinkage nylon elastomer foaming material is 0.2% to 0.8%, the vertical resilience is 75% to 90%, and the density is 0.05 to 0.10 g / cm<supgt;3< / supgt;. The nylon elastomer foaming material provided by the present invention has a low shrinkage rate, good vertical resilience, and a high foaming ratio. This nylon elastomer foaming material can be used in the fields of shoe insoles, mid-soles, saddles, tires, helmets, cushion pads, interior decorations, sports equipment, etc.

Description

Technical Field

[0001] The present invention belongs to the technical field of elastomeric materials, and relates to a low-shrinkage nylon elastomer foaming material, a preparation method thereof, and an application thereof. Background Art

[0002] At present, the foaming processes of nylon elastomer foaming materials mainly include bead foaming, sheet foaming, mold foaming, microcellular injection molding, etc.

[0003] The supercritical fluid foaming technology uses supercritical CO 2 / N 2 and other inert gases as foaming gases for foaming. Compared with traditional physical foaming agents such as alkanes and chlorofluorocarbons, supercritical fluids have the advantages of wide sources, environmental friendliness, and non-flammability. However, the particles after foaming with supercritical CO 2 have serious shrinkage problems. This serious 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, seriously affecting the subsequent use of the foaming material. At present, methods such as blending other polymers, size stabilizers or nucleating agents are generally used to improve the shrinkage problem, but these methods will increase the cost on the one hand and reduce the foaming ratio on the other hand.

[0004] CN116323138A discloses a method and equipment for manufacturing a foamed article, in which a thermoplastic elastomer material and carbon dioxide are used for foaming. By injecting carbon dioxide into a solid foamable material and expanding the carbon dioxide without softening the solid material, a foaming material with a low density, uniform porous foam structure and beneficial properties can be formed. However, using the method of this invention, during the heating and pressurization process, the state of the material changes, and a uniform cell structure cannot be obtained.

[0005] Therefore, in this field, there is a desire to develop a nylon elastomer foaming material that has a low shrinkage rate, a high foaming ratio, a uniform cell distribution, and a low cost. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a low-shrinkage nylon elastomer foaming material, a preparation method thereof, and an application thereof. The preparation method of the low-shrinkage nylon elastomer foaming material provided by the present invention overcomes the problem of complex process of the foaming method of nylon elastomers in the prior art and solves the defect of large shrinkage rate of the foaming material. The supercritical fluid foaming method adopted by the present invention has a simple process and low energy consumption, effectively improving the production efficiency; at the same time, the nylon elastomer foaming material prepared by the present invention has a high foaming ratio, a small shrinkage rate, a small cell diameter, and excellent mechanical properties.

[0007] To achieve the object of the present invention, the following technical solutions are adopted in the present invention:

[0008] In a first aspect, the present invention provides a low-shrinkage nylon elastomer foaming material, and the shrinkage rate of the low-shrinkage nylon elastomer foaming material is 0.2% to 0.8% (such as 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, etc.), the vertical resilience is 75% to 90% (such as 75%, 76%, 77%, 78%, 79%, 80%, 82%, 84%, 86%, 88%, 90%, etc.), and the density is 0.05 to 0.10 g / cm 3 (such as 0.05 g / cm 3 , 0.06 g / cm 3 , 0.07 g / cm 3 , 0.08 g / cm 3 , 0.09 g / cm 3 , 0.10 g / cm 3 etc.).

[0009] The nylon elastomer foaming material provided by the present invention has a low shrinkage rate, good vertical resilience, and a high foaming ratio. The nylon elastomer foaming material can be used in the fields of shoe insoles, mid-soles, saddles, tires, helmets, cushion pads, indoor decorations, sports equipment, etc.

[0010] In a second aspect, the present invention provides a preparation method of the low-shrinkage nylon elastomer foaming material as described in the first aspect, and the preparation method includes:

[0011] Adding a nylon elastomer into a container, then injecting a supercritical fluid, and rising to a foaming temperature in a segmented heating manner for foaming to obtain the low-shrinkage nylon elastomer foaming material;

[0012] The average torque value of the nylon elastomer within the range of 150 °C and 100 - 200 s is 5 - 60 N·m, such as 5 N·m, 8 N·m, 10 N·m, 12 N·m, 14 N·m, 16 N·m, 18 N·m, 20 N·m, 22 N·m, 24 N·m, 26 N·m, 28 N·m, 30 N·m, 32 N·m, 34 N·m, 36 N·m, 38 N·m, 40 N·m, 42 N·m, 44 N·m, 46 N·m, 48 N·m, 50 N·m, 52 N·m, 54 N·m, 56 N·m, 58 N·m, 60 N·m, etc. The test method for the average torque value is as follows: Use a torque rheometer for testing, the test temperature is 150 °C, the test time is 8 - 12 min, the sample addition amount is 30 - 50 g, and the average value within the range of 100 s - 200 s is taken.

[0013] The preparation method of the low-shrinkage nylon elastomer foaming material provided by the present invention adopts the supercritical fluid foaming technology. By limiting the average torque of the nylon elastomer within a specific range at 150 °C for 100 - 200 s, and adopting a stepwise heating method to raise the temperature to the foaming temperature for foaming, the obtained nylon elastomer foaming material has a low relative density, uniform cell distribution, a low shrinkage rate (0.2% - 0.8%), and a high vertical resilience (75% - 90%). This nylon elastomer foaming material can be used in the fields of insoles, mid-soles, saddles, tires, helmets, cushion pads, indoor decorations, and sports equipment, etc.

[0014] Preferably, the average torque of the nylon elastomer within the range of 150 °C for 100 - 200 s is 5 - 40 N·m.

[0015] Preferably, the container includes any one of a high-pressure reaction kettle and a foaming kettle.

[0016] Preferably, the supercritical fluid includes any one or a combination of at least two of carbon dioxide, nitrogen, helium, and argon, preferably carbon dioxide and / or nitrogen.

[0017] Preferably, after injecting the supercritical fluid, the supercritical state is maintained.

[0018] Preferably, the pressure for maintaining the supercritical state is 10 - 100 MPa, such as 10 MPa, 15 MPa, 20 MPa, 25 MPa, 30 MPa, 35 MPa, 40 MPa, 45 MPa, 50 MPa, 55 MPa, 60 MPa, 65 MPa, 70 MPa, 75 MPa, 80 MPa, 85 MPa, 90 MPa, 95 MPa, 100 MPa, etc., preferably 10 - 50 MPa.

[0019] Preferably, the heating rate of the stepwise heating is 5 - 20 °C / min, such as 5 °C / min, 6 °C / min, 8 °C / min, 10 °C / min, 12 °C / min, 14 °C / min, 16 °C / min, 18 °C / min, 20 °C / min, etc., preferably 10 - 15 °C / min.

[0020] Preferably, during the stepwise heating, every time the temperature is raised by 30 - 50 °C (such as 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, etc.), it is kept at a constant temperature for 10 - 30 min (such as 10 min, 13 min, 15 min, 16 min, 18 min, 20 min, 23 min, 25 min, 28 min, 30 min, etc.), preferably kept at a constant temperature for 15 - 20 min.

[0021] Preferably, the foaming temperature is (T m - 40 °C) - (Tm +10 °C), for example, T m -40 °C, T m -35 °C, T m -30 °C, T m -25 °C, T m -20 °C, T m -15 °C, T m -10 °C, T m -5 °C, T m °C, T m +5 °C, T m +10 °C, etc., preferably (T m -30 °C) to (Tm), where T m is the melting temperature of the nylon elastomer.

[0022] Preferably, the pressure for foaming is 10 to 50 MPa, such as 10 MPa, 15 MPa, 20 MPa, 25 MPa, 30 MPa, 35 MPa, 40 MPa, 45 MPa, 50 MPa, etc.

[0023] Preferably, the raw materials for preparing the nylon elastomer include polyamide and polyglycol, where polyamide serves as the hard segment of the nylon elastomer and polyglycol serves as the soft segment of the nylon elastomer.

[0024] Preferably, the polyamide is selected from any one or a combination of at least two of PA6, PA11, PA12, PA5.4, PA5.9, PA5.10, PA5.12, PA5.13, PA5.14, PA5.16, PA5.18, PA5.36, PA6.4, PA6.9, PA6.10, PA6.12, PA6.13, PA6.14, PA6.16, PA6.18, PA6.36, PA10.4, PA10.9, PA10.10, PA10.12, PA10.13, PA10.14, PA10.16, PA10.18, PA10.36, PA10.T, PA12.4, PA12.9, PA12.10, PA12.12, PA12.13, PA12.14, PA12.16, PA12.18, PA12.36 or PA12.T.

[0025] Preferably, the polyglycol is selected from any one or a combination of at least two of polytetrahydrofuran ether glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, polycaprolactone, polyester diol synthesized from diol and dibasic acid, and polycarbonate diol.

[0026] Preferably, the molar ratio of the polyamide to the polyglycol is (0.98 to 1.02):1, such as 0.98:1, 0.99:1, 1:1, 1.01:1, 1.02:1, etc.

[0027] Preferably, the raw materials for preparing the nylon elastomer further include a catalyst and / or an antioxidant.

[0028] Preferably, the catalyst includes zirconium butoxide and / or tetrabutyl titanate.

[0029] Preferably, the antioxidant includes antioxidant 168 and / or antioxidant 1098.

[0030] Preferably, based on the total weight of the polyamide and the polyglycol being 100%, the dosage of the catalyst is 0.1% to 0.3%, such as 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, etc.

[0031] Preferably, based on the total weight of the polyamide and the polyglycol being 100%, the dosage of the antioxidant is 0 to 0.5%, such as 0 (i.e., not added), 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, 0.5%, etc.

[0032] Preferably, the hardness of the nylon elastomer is 20 to 55D, such as 20D, 25D, 30D, 35D, 40D, 45D, 50D, 55D, etc., and preferably 25 to 45D.

[0033] Preferably, the form of foaming of the nylon elastomer is not limited and can be bead foaming, post-foaming of plates, injection foaming, compression molding foaming, extrusion foaming, and a foamed material with a low density, uniform porous foam structure and beneficial properties can be formed.

[0034] Preferably, the nylon elastomer is prepared by the following method:

[0035] The polyamide and the polyglycol are melted, then an optional catalyst and an optional antioxidant are added, reacted, and extruded and pelletized to obtain the nylon elastomer.

[0036] Preferably, the melting is carried out under an inert gas atmosphere.

[0037] Preferably, the inert gas includes nitrogen.

[0038] Preferably, the temperature of the reaction is 200 to 240 °C, such as 200 °C, 205 °C, 210 °C, 215 °C, 220 °C, 225 °C, 230 °C, 235 °C, 240 °C, etc., and the reaction time is 2 to 4 h, such as 2 h, 2.5 h, 3 h, 3.5 h, 4 h, etc.

[0039] Preferably, the temperature of the extrusion granulation is 160-230 °C, such as 160 °C, 170 °C, 180 °C, 190 °C, 200 °C, 210 °C, 220 °C, 230 °C, etc.

[0040] As a preferred technical solution of the present invention, the preparation method includes:

[0041] (1) Melting polyamide and polyglycol in an inert gas atmosphere, then adding an optional catalyst and an optional antioxidant, reacting at 200-240 °C for 2-4 h, and extruding and granulating at 160-230 °C to obtain a nylon elastomer; the average torque value of the nylon elastomer within the range of 150 °C and 100-200 s is 5-60 N·m;

[0042] (2) Adding the nylon elastomer obtained in step (1) into a container, then injecting a supercritical fluid, and using a stepwise heating method to raise the temperature to the foaming temperature at a heating rate of 5-20 °C / min, and keeping the temperature constant for 10-30 min every time the temperature rises by 30-50 °C, and foaming at 10-50 MPa to obtain the low-shrinkage nylon elastomer foaming material.

[0043] In the third aspect, the present invention provides an application of the low-shrinkage nylon elastomer foaming material as described in the first aspect in insoles, shoe midsoles, saddles, tires, helmets, cushions, indoor decorations, and sports equipment.

[0044] Compared with the prior art, the present invention has the following beneficial effects:

[0045] The nylon elastomer foaming material provided by the present invention has a low shrinkage rate, good vertical resilience, and a high foaming ratio. The nylon elastomer foaming material can be used in the fields of insoles, shoe midsoles, saddles, tires, helmets, cushions, indoor decorations, and sports equipment. Description of the Drawings

[0046] Figure 1 It is a torque test curve graph of the nylon elastomer obtained in step (1) of Example 1 of the present invention.

[0047] Figure 2 It is an SEM image of the nylon elastomer foaming material provided by Example 1 of the present invention.

[0048] Figure 3 It is an SEM image of the nylon elastomer foaming material provided by Comparative Example 2 of the present invention. Detailed Embodiments

[0049] The technical solution of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention. The experimental methods without specific conditions in the following embodiments are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0050] Example 1

[0051] In this embodiment, a low-shrinkage nylon elastomer foaming material is provided, and its preparation method includes the following steps:

[0052] (1) 1 mol of polyamide (polyamide 612, number average molecular weight of 500) and 1 mol of polyglycol (polytetramethylene glycol, number average molecular weight of 1500) are melted under a nitrogen atmosphere, and then 0.1% of zirconium butoxide and 0.2% of antioxidant 168 based on the total weight of polyamide and polyglycol are added, and the reaction is carried out at 200 °C for 4 h, and then extruded and pelletized through a 160 °C discharge port to obtain a nylon elastomer;

[0053] (2) Preparation of foamed beads: 1 kg of the above-mentioned nylon elastomer, 15 MPa of carbon dioxide and 1 kg of water are charged into a 20 L high-pressure reactor to form a suspension, and then the temperature is raised to 140 °C at a heating rate of 10 °C / min, and every time the temperature is raised by 40 °C, it is kept at a constant temperature for 20 min, and the pressure is kept at 15 MPa for foaming. The suspension in the pressure vessel is discharged into the atmospheric environment and dried to obtain foamed beads.

[0054] The obtained foamed beads are filled into a mold with a length of 300 mm × a width of 200 mm × a thickness of 40 mm, and compressed by 15% along the thickness direction of the mold with 1.2 bar of steam to bond the particles into a shape, and finally a molded foam product is obtained, and then it is placed at room temperature for 48 h.

[0055] Example 2

[0056] In this embodiment, a low-shrinkage nylon elastomer foaming material is provided, and its preparation method includes the following steps:

[0057] (1) 0.995 mol of polyamide (polyamide 12, number average molecular weight of 500) and 1 mol of polyglycol (polytetramethylene glycol, number average molecular weight of 2000) are melted under a nitrogen atmosphere, and then 0.25% of zirconium butoxide and 0.5% of antioxidant 168 based on the total weight of polyamide and polyglycol are added, and the reaction is carried out at 240 °C for 3 h, and then extruded and pelletized through a 230 °C discharge port to obtain a nylon elastomer;

[0058] (2) Preparation of the foamed sheet: The above-mentioned nylon elastomer was extruded through a screw to obtain a 15-mm thick sheet. The sheet was placed in a foaming kettle, filled with 10 MPa of carbon dioxide and 15 MPa of nitrogen, and then heated to 145 °C at a heating rate of 15 °C / min. And for every 30 °C increase in temperature, it was kept at a constant temperature for 10 min, with the pressure maintained at 25 MPa for foaming. The carbon dioxide and nitrogen in the pressure vessel were discharged into the atmospheric environment to obtain the foamed sheet.

[0059] Example 3

[0060] In this example, a low-shrinkage nylon elastomer foamed material is provided, and its preparation method includes the following steps:

[0061] (1) 1.01 mol of polyamide (polyamide 12, number-average molecular weight of 1000) and 1 mol of polyglycol (polytetramethylene glycol, number-average molecular weight of 2000) were melted under a nitrogen atmosphere, and then zirconium butoxide accounting for 0.15% of the total weight of the polyamide and polyglycol was added, and the reaction was carried out at 220 °C for 3 h. Granulation was carried out by extrusion through a 220 °C discharge port to obtain the nylon elastomer;

[0062] (2) Preparation of the foamed sheet: The above-mentioned nylon elastomer was extruded through a screw to obtain a 15-mm thick sheet. The sheet was placed in a foaming kettle, filled with 7 MPa of carbon dioxide and 13 MPa of nitrogen, and then heated to 145 °C at a heating rate of 10 °C / min. And for every 20 °C increase in temperature, it was kept at a constant temperature for 10 min, with the pressure maintained at 20 MPa for foaming. The carbon dioxide and nitrogen in the pressure vessel were discharged into the atmospheric environment to obtain the foamed sheet.

[0063] Example 4

[0064] In this example, a low-shrinkage nylon elastomer foamed material is provided, and its preparation method includes the following steps:

[0065] (1) 1.01 mol of polyamide (polyamide 612, number-average molecular weight of 1000) and 1 mol of polyglycol (polypropylene glycol, number-average molecular weight of 1000) were melted under a nitrogen atmosphere, and then tetrabutyl titanate accounting for 0.15% of the total weight of the polyamide and polyglycol and 0.3% of antioxidant 1098 were added in sequence. The reaction was carried out at 220 °C for 3 h. Granulation was carried out by extrusion through a 200 °C discharge port to obtain the nylon elastomer;

[0066] (2) The above-mentioned nylon elastomer was injection-molded into a small blank of the midsole of a shoe, and then placed in a foaming kettle, filled with 5 MPa of carbon dioxide and 25 MPa of nitrogen, and then heated to 125 °C at a heating rate of 5 °C / min. And for every 50 °C increase in temperature, it was kept at a constant temperature for 30 min, with the pressure maintained at 30 MPa for foaming. The carbon dioxide and nitrogen in the pressure vessel were discharged into the atmospheric environment to obtain a large blank of the foamed shoe material.

[0067] Example 5

[0068] In this example, a low-shrinkage nylon elastomer foaming material is provided, and its preparation method includes the following steps:

[0069] (1) 1 mol of polyamide (polyamide 612, number-average molecular weight of 1000) and 1 mol of polyglycol (PTMEG, number-average molecular weight of 1000) are melted under a nitrogen atmosphere, and then tetrabutyl titanate accounting for 0.3% of the total weight of polyamide and polyglycol is added, and the reaction is carried out at 230 °C for 2 h, and pelletized by extrusion through a 200 °C discharge port to obtain a nylon elastomer;

[0070] (2) The above nylon elastomer is added to the screw system of an injection molding machine, 5 MPa of carbon dioxide and 15 MPa of nitrogen are filled, and then the temperature is raised to 160 °C at a heating rate of 20 °C / min, and every time the temperature is raised by 30 °C, it is kept at a constant temperature for 30 min, and the pressure is kept at 20 MPa, and then the melt is injected into the mold cavity through a switching nozzle to obtain an injection-molded foamed sheet.

[0071] Example 6

[0072] In this example, a low-shrinkage nylon elastomer foaming material is provided, and its preparation method includes the following steps:

[0073] (1) 1 mol of polyamide (polyamide 612, number-average molecular weight of 1000) and 1 mol of polyglycol (polypropylene glycol, number-average molecular weight of 1000) are melted under a nitrogen atmosphere, and then tetrabutyl titanate accounting for 0.2% of the total weight of polyamide and polyglycol and 0.2% of antioxidant 1098 are added, and the reaction is carried out at 200 °C for 4 h, and pelletized by extrusion through a 180 °C discharge port to obtain a nylon elastomer;

[0074] (2) Preparation of the foamed sheet: The above nylon elastomer is extruded through a screw to obtain a 10-mm-thick sheet, the sheet is placed in a foaming kettle, 5 MPa of carbon dioxide and 15 MPa of nitrogen are filled, and then the temperature is raised to 145 °C at a heating rate of 10 °C / min, and every time the temperature is raised by 50 °C, it is kept at a constant temperature for 20 min, and the pressure is kept at 20 MPa, and foaming is carried out, and the carbon dioxide and nitrogen in the pressure vessel are discharged into the atmospheric environment to obtain a foamed sheet.

[0075] Example 7

[0076] The difference between this example and Example 1 is only that in step (2), every time the temperature is raised by 55 °C, it is kept at a constant temperature for 20 min.

[0077] Example 8

[0078] The difference between this example and Example 1 is only that in step (2), the temperature is raised to 140 °C at a heating rate of 25 °C / min.

[0079] Comparative Example 1

[0080] In this comparative example, a low-shrinkage nylon elastomer foaming material is provided, and its preparation method includes the following steps:

[0081] (1) 1 mol of polyamide (polyamide 612, number average molecular weight of 500) and 1 mol of polyglycol (polypropylene glycol, number average molecular weight of 3000) are melted under a nitrogen atmosphere, and then 0.2% of tetrabutyl titanate and 0.2% of antioxidant 1098 based on the total weight of polyamide and polyglycol are added, and the reaction is carried out at 200 °C for 4 h, and then extruded and pelletized through an outlet at 180 °C to obtain a nylon elastomer;

[0082] (2) Preparation of the foamed sheet: The above-mentioned nylon elastomer is extruded through a screw to obtain a 10-mm-thick sheet, and the sheet is placed in a foaming kettle, filled with 5 MPa of carbon dioxide and 15 MPa of nitrogen, and then heated to 145 °C at a heating rate of 10 °C / min, and for every 50 °C increase, it is kept at a constant temperature for 20 min, and the pressure is maintained at 20 MPa for foaming. The carbon dioxide and nitrogen in the pressure vessel are discharged into the atmospheric environment to obtain a foamed sheet.

[0083] Comparative Example 2

[0084] The difference between this comparative example and Example 1 is only that in step (2), the step of "and for every 40 °C increase, it is kept at a constant temperature for 20 min" is not included, that is, the foaming temperature is not reached by the segmented heating method.

[0085] The nylon elastomers obtained in the steps (1) of the examples and comparative examples are tested, and the test methods are as follows:

[0086] (1) Torque: Test is carried out using a torque rheometer model RM200C produced by Harbin Hapu Electric Technology Co., Ltd., the test temperature is 150 °C, the test time is 10 min, the sample addition amount is 40 g, and the average value in the range of 100 s to 200 s is taken;

[0087] (2) Hardness: Test is carried out in accordance with ASTM D2240-15(2021).

[0088] The test results are shown in Table 1.

[0089] The torque test curve of the nylon elastomer obtained in step (1) of Example 1 of the present invention is as Figure 1 shown.

[0090] The nylon elastomer foaming materials provided in the examples and comparative examples are subjected to debarking on the surface by a slicing machine, and then cut into samples according to the test standard, and their performance is tested. The test methods are as follows:

[0091] (1) Shrinkage rate: Tested in accordance with ISO 294-4 2577;

[0092] (2) Ball rebound: Tested in accordance with ASTM 2632;

[0093] (3) Density: Tested in accordance with ASTM D792.

[0094] The performance test results are shown in Table 1.

[0095] Table 1

[0096]

[0097] As can be seen from Table 1, the nylon elastomer foaming materials provided in the embodiments of the present invention all have a low shrinkage rate (0.3% - 0.8%) and good ball rebound resilience (81% - 84%), and a high foaming ratio (density: 0.05 - 0.10 g / cm 3 )

[0098] Compared with Example 6, the shrinkage rate of the nylon elastomer foaming material provided in Comparative Example 1 is significantly increased, and the ball rebound resilience is significantly deteriorated.

[0099] Compared with Example 1, the shrinkage rate of the nylon elastomer foaming material provided in Comparative Example 2 is significantly increased, and the ball rebound resilience is significantly deteriorated.

[0100] The SEM diagrams of the nylon elastomer foaming materials provided in Example 1 of the present invention and Comparative Example 2 are respectively as Figure 2 and Figure 3 shown. It can be seen that compared with Comparative Example 2, the cell structure of the nylon elastomer foaming material provided in Example 1 is more uniform.

[0101] The applicant declares that the present invention uses the above embodiments to illustrate the low-shrinkage nylon elastomer foaming material and its preparation method and application of the present invention. However, 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, the equivalent substitution of the raw materials selected for the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A low shrinkage nylon elastomer foam material, characterized in that: The preparation method of the low shrinkage nylon elastomer foam material comprises: Adding a nylon elastomer into a container, then injecting a supercritical fluid, and heating the container in stages to a foaming temperature for foaming to obtain the low shrinkage nylon elastomer foam material; The torque average value of the nylon elastomer at 150°C and within the range of 100 to 200 seconds is 5 to 30 N·m; The heating rate of the staged heating is 5 to 20°C / min; When the temperature is raised in stages, the temperature is kept constant for 10 to 30 minutes every time the temperature is raised by 30 to 50°C. The low shrinkage nylon elastomer foam material has a shrinkage rate of 0.2% to 0.7%, a vertical resilience of 75% to 90%, and a density of 0.05 to 0.07 g / cm 3 ; The foaming temperature is (T m -40℃)~(T m +10℃), where T m is the melting temperature of nylon elastomer; The foaming pressure is 10-50Mpa; The test method of the torque average value is: using a torque rheometer model RM200C produced by Harbin Harpu Electric Technology Co., Ltd. for testing, the test temperature is 150°C, the test time is 10 minutes, the sample addition amount is 40g, and the average value within the range of 100s to 200s is taken; The shrinkage is tested according to ISO 294-4 2577: The vertical resilience is tested according to ASTM 2632; The nylon elastomer is prepared by the following method: The polyamide and the polyglycol are melted under an inert gas atmosphere, and then an optional catalyst and an optional antioxidant are added, reacted at 200 to 240° C. for 2 to 4 hours, and extruded and granulated at 160 to 230° C. to obtain the nylon elastomer; The molar ratio of the polyamide to the polyglycol is (0.98-1.02):1; The polyamide is polyamide 612, and the polyglycol is polybutylene glycol; or The polyamide is polyamide 12, and the polyglycol is polybutylene glycol; or The polyamide is polyamide 612, and the polyglycol is polypropylene glycol; or The polyamide is polyamide 612, and the polyglycol is PTMEG.

2. The low shrinkage nylon elastomer foam material according to claim 1, characterized in that: The supercritical fluid includes any one of carbon dioxide, nitrogen, helium, and argon, or a combination of at least two of them.

3. The low shrinkage nylon elastomer foam material according to claim 1, characterized in that: Based on the total weight of the polyamide and the polyglycol being 100%, the amount of the catalyst is 0.1% to 0.3%, and the amount of the antioxidant is 0 to 0.5%.

4. The method for preparing the low shrinkage nylon elastomer foam material according to any one of claims 1 to 3, characterized in that: The preparation method comprises: (1) melting polyamide and polyglycol under an inert gas atmosphere, then adding an optional catalyst and an optional antioxidant, reacting at 200 to 240° C. for 2 to 4 hours, and extruding and granulating at 160 to 230° C. to obtain a nylon elastomer; the nylon elastomer has an average torque of 5 to 30 N·m at 150° C. and within a range of 100 to 200 seconds; (2) The nylon elastomer obtained in step (1) is added into a container, and then a supercritical fluid is injected. The temperature is raised to the foaming temperature at a rate of 5 to 20°C / min in a stepwise manner, and the temperature is kept constant for 10 to 30 minutes every time the temperature is raised by 30 to 50°C. The foaming is carried out at 10 to 50 MPa to obtain the low shrinkage nylon elastomer foam material.

5. Use of the low shrinkage nylon elastomer foam material according to any one of claims 1 to 3 in insoles, midsoles, saddles, tires, helmets, and interior decorations.

6. Use of the low shrinkage nylon elastomer foam material according to any one of claims 1 to 3 in a cushion.

7. Use of the low shrinkage nylon elastomer foam material according to any one of claims 1 to 3 in sports equipment.

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