A cushioning article and methods of making and using the same

Abstract

The application discloses a kind of buffer products and its preparation method and application, belong to foamed material technical field.Preparation method: fiber network is mixed with polymer matrix and is supercritical foaming, obtains the buffer product;The melting point of the fiber network is higher than the temperature of supercritical foaming, and the temperature of supercritical foaming is higher than the melting point of the polymer matrix;The plane size of the fiber network is 0.4~0.8 times of the plane size of buffer product;The thickness of the fiber network is 0.1~2mm;The mass of the fiber network is 3~15% of the total mass of fiber network and polymer matrix.The application utilizes fiber network and microporous foaming structure to form synergistic interpenetrating composite structure, realizes material light weight, high resilience, environmental protection weather resistance.Product density is 0.08~0.20 g / cm 3 ;Resilience is >70%;Without adding chemical foaming agent throughout;Compression permanent set is <10%.

Description

Technical Field

[0001] This invention relates to the field of foamed materials, specifically to a cushioning product, its preparation method, and its application. Background Technology

[0002] Traditional cushioning materials (such as EVA and PU foam) suffer from problems such as high density, insufficient resilience, and environmental pollution caused by the use of chemical foaming agents (such as azodicarbonamide) in the production process. Although supercritical foaming technology (such as supercritical CO2 foaming) can achieve green production, the mechanical strength, resilience durability, and dimensional stability of single foam materials still have significant shortcomings, which limit the application of high-end cushioning products. Summary of the Invention

[0003] The purpose of this invention is to provide a lightweight, highly resilient, low-compression-deformation, and environmentally friendly cushioning product and its preparation method.

[0004] This invention provides a method for preparing a cushioning product, comprising the following steps: The fiber web is mixed with a polymer matrix and subjected to supercritical foaming to obtain the cushioning product. The melting point of the fiber web is higher than the temperature of supercritical foaming, and the temperature of supercritical foaming is higher than the melting point of the polymer matrix. The planar dimensions of the fiber web are 0.4 to 0.8 times the planar dimensions of the cushioning product; the thickness of the fiber web is 0.1 to 2 mm. The mass of the fiber web is 3 to 15% of the total mass of the fiber web and the polymer matrix.

[0005] Preferably, the thickness of the fiber web is 0.1~2mm; The porosity of the fiber web is 60-90%, and the diameter of the fibers in the fiber web is 1-100 μm.

[0006] Preferably, the method for preparing the fiber web includes: electrospinning or meltblowing the fiber web raw material; The polymer matrix is ​​one or both of TPU and TPEE; the TPU includes E-TPU.

[0007] Preferably, the melting point of the fiber web is 180~260℃, and the melting point of the polymer matrix is ​​100~150℃.

[0008] Preferably, the supercritical foaming includes sequential saturation adsorption and pressure relief foaming; The gas used in the supercritical foaming includes supercritical carbon dioxide or supercritical nitrogen. The saturation adsorption temperature is 80~160℃, the pressure is 8~30MPa, and the time is 1~4h; the depressurization rate of the depressurization foaming is 0.5~5MPa / min.

[0009] Preferably, after supercritical foaming is completed, the resulting blank is hot-pressed for shaping; the hot-pressing temperature is 90~150℃, the pressure is 2~10MPa, and the holding time is 5~30min.

[0010] The present invention also provides a cushioning article prepared by the preparation method described above, comprising a foamed polymer matrix and a fiber network dispersed and embedded in the foamed polymer matrix; The foamed polymer matrix has a cell diameter of 10~300μm and a closed-cell rate of >80%.

[0011] Preferably, the fiber web has ≥2 layers, adjacent fiber webs are arranged in parallel with equal spacing, and the interlayer spacing is 0.5~5mm.

[0012] The present invention also provides the application of the cushioning products described above in footwear materials, sports protective gear, car seats, mattresses, cushions or packaging materials.

[0013] This invention achieves a synergistic effect of fiber reinforcement and foaming molding by strictly controlling the hierarchical relationship between the material's melting point and foaming temperature. 1. Melting point hierarchy: The foaming temperature is higher than the melting point of the polymer matrix, which allows the polymer matrix to fully melt and plasticize under the action of supercritical fluid, forming a continuous melt phase, providing a stable nucleation and growth environment for subsequent pressure relief foaming; the foaming temperature is lower than the melting point of the fiber web, which allows the fiber web to maintain a solid fiber structure during the foaming process, without melting, shrinking or degrading, thereby forming a stable three-dimensional reinforcing skeleton inside the foam matrix, significantly improving the mechanical strength, collapse resistance and resilience durability of the product.

[0014] 2. Dosage and Proportion: The mass ratio of the fiber web to the total mass of the polymer matrix should be controlled between 3% and 15%. This ensures that the fiber web forms a continuous reinforcing skeleton while avoiding excessive fiber content that could negatively impact the foaming and molding of the matrix. If the fiber web percentage is too low (<3%), the fiber-reinforced skeleton will be insufficient, making it difficult to effectively improve the material's resistance to collapse and its resilience and durability. If the fiber web percentage is too high (>15%), it will hinder the continuous melting and cell growth of the polymer matrix, easily leading to uneven cell structure and decreased mechanical properties.

[0015] 3. Size Fit: The initial planar size of a single fiber web is 0.4 to 0.8 times the planar size of the cushioning product, and the initial thickness is 0.1 to 2 mm. This is to accommodate the matrix's planar expansion rate of 1.2 to 2.5 times and thickness expansion rate of 1.5 to 3 times, ensuring that the fiber web is evenly distributed in the matrix after foaming without wrinkles or shifting. If the fiber web size is too large, wrinkles and shifting are likely to occur after foaming; if the size is too small, a continuous reinforcing structure cannot be formed, leading to uneven local mechanical properties.

[0016] The buffer product prepared by this invention forms a fiber-cell interpenetrating network structure, with the following properties: Density 0.08~0.20 g / cm³ 3 It reduces energy consumption by 30-50% compared to traditional EVA; its resilience is >70%, and its energy return rate is higher than that of ordinary single-foamed materials; it contains no chemical foaming agents and meets RoHS / REACH requirements; its compression set is <10% (ASTM D395), making it durable and resistant to collapse. Detailed Implementation

[0017] This invention provides a method for preparing a cushioning product, comprising the following steps: The fiber web is mixed with a polymer matrix and subjected to supercritical foaming to obtain the cushioning product. The melting point of the fiber web is higher than the supercritical foaming temperature, and the supercritical foaming temperature is higher than the melting point of the polymer matrix. The supercritical foaming temperature, being higher than the melting point of the polymer matrix, allows the polymer matrix to fully melt and plasticize under the action of supercritical fluid, forming a continuous melt phase and providing a stable nucleation and growth environment for subsequent pressure relief foaming. The supercritical foaming temperature, being lower than the melting point of the fiber web, allows the fiber web to maintain a solid fiber structure during foaming, preventing melting, shrinkage, or degradation. This results in the formation of a stable three-dimensional reinforcing skeleton within the foamed matrix, significantly improving the mechanical strength, collapse resistance, and resilience of the product.

[0018] In this invention, the mass of the fiber web is preferably 3-15% of the total mass of the fiber web and the polymer matrix. In specific embodiments of this invention, it can be 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, or 14%. Controlling the ratio of the fiber web mass to the total mass of the polymer matrix between 3-15% ensures that the fiber web forms a continuous reinforcing skeleton while avoiding an excessively high fiber proportion that could negatively impact the foaming and molding of the matrix. If the fiber web proportion is too low (<3%), the fiber-reinforced skeleton is insufficient, making it difficult to effectively improve the material's resistance to collapse and its resilience and durability. If the fiber web proportion is too high (>15%), it will hinder the continuous melting and cell growth of the polymer matrix, easily leading to uneven cell structure and decreased mechanical properties.

[0019] In this invention, the initial planar dimension of the fiber web is preferably 0.4 to 0.8 times the planar dimension of the cushioning product. In specific embodiments, it can be 0.5, 0.6, or 0.7 times. The thickness of the fiber web is preferably 0.1 to 2 mm. In specific embodiments, it can be 0.5 mm, 0.8 mm, 1 mm, 1.2 mm, 1.5 mm, or 1.8 mm. The initial planar dimension of a single fiber web is 0.4 to 0.8 times the planar dimension of the cushioning product, and the thickness is 0.1 to 2 mm, to accommodate the 1.2 to 2.5 times planar expansion rate and 1.5 to 3 times thickness expansion rate of the matrix, ensuring that the fiber web is uniformly distributed in the matrix after foaming without wrinkles or displacement. If the fiber web size is too large, wrinkles and displacement are likely to occur after foaming; if the size is too small, a continuous reinforcing structure cannot be formed, leading to uneven local mechanical properties.

[0020] In this invention, the method for preparing the fiber web preferably includes the following steps: The fiber web is obtained by electrospinning or meltblowing the fiber web raw material.

[0021] In this invention, the fiber web material preferably includes one or more of TPU, TPEE, and PLA. The TPU is preferably BASF 1185A; the PLA is preferably Fengyuan FY602 and / or NatureWorks6202D; and the TPEE is preferably DuPont Hytrel 4056.

[0022] In this invention, the porosity of the fiber web is preferably 60-90%, and in specific embodiments of this invention it can be 65%, 70%, 75%, 80% or 85%. The diameter of the fibers in the fiber web is preferably 1-100 μm, and in specific embodiments of this invention it can be 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm or 90 μm.

[0023] In this invention, the polymer matrix preferably includes one or both of TPU and TPEE; the TPU type used is preferably one or both of BASF 1185A and Wanhua WHT-1570; the TPEE type used is preferably one or more of DuPont Hytrel4056, DuPont Hytrel® 40D, DuPont Hytrel® 55D and LG BT-1155D.

[0024] In this invention, the supercritical foaming includes sequential saturation adsorption and pressure relief foaming; The preferred saturation adsorption temperature is 80-160℃, the preferred pressure is 8-30 MPa, and the preferred time is 1-4 h. In specific embodiments of the present invention, the saturation adsorption temperature can be 90, 100, 110, 120, 130, 140, or 150℃, the preferred pressure can be 10 MPa, 12 MPa, 15 MPa, 18 MPa, 20 MPa, 25 MPa, or 28 MPa, and the preferred time can be 2 h or 3 h. The preferred depressurization rate of the depressurization foaming is 0.5-5 MPa / min, and in specific embodiments of the present invention, it can be 1 MPa / min, 2 MPa / min, 3 MPa / min, or 4 MPa / min. After depressurization foaming, a fiber-cell interpenetrating network structure is formed.

[0025] In this invention, the gas used for supercritical foaming preferably includes supercritical carbon dioxide or supercritical nitrogen.

[0026] Following the supercritical foaming process, the present invention preferably further includes hot-pressing the resulting material. Hot-pressing enhances interfacial bonding and dimensional stability.

[0027] The present invention also provides a cushioning article prepared by the preparation method described above, comprising a foamed polymer matrix and a fiber web dispersed in the foamed polymer matrix.

[0028] In this invention, the number of fiber webs is preferably ≥2, and adjacent fiber webs are distributed in parallel.

[0029] In this invention, the foaming material preferably has a pore diameter of 10-300 μm and a closed-cell rate preferably >80%.

[0030] The present invention also provides the application of the above-mentioned cushioning products in footwear materials, sports protective gear, car seats, mattresses, cushions or packaging materials.

[0031] The following detailed description of the cushioning products, their preparation methods, and applications provided by the present invention, with reference to specific embodiments, should not be construed as limiting the scope of protection of the present invention.

[0032] Example 1: Fiber-reinforced supercritical foam cushioning material for sports shoe midsoles The following steps are taken to prepare a fiber-reinforced cushioning material for the midsole of athletic shoes in this embodiment: 1. Preparation of fiber web: TPU fiber web was prepared by electrospinning. The TPU used was BASF 1185A, which has a melt temperature of 185℃. The process parameters were controlled to make the fiber diameter 20 μm, the fiber web porosity 85%, and the initial thickness 0.5 mm. 2. Raw material ratio and loading: Weigh the above TPU fiber mesh and low melting point foamed TPU (melting temperature is 115℃) at a mass ratio of 8:92. Lay the fiber mesh flat in the mold, and then fill the pores and upper and lower layers of the fiber mesh evenly with TPEE particles. After compounding, load it into a supercritical foaming reactor and seal it.

[0033] 3. Supercritical foaming process: Supercritical CO2 medium is introduced into the reactor, pressurized to 15 MPa, heated to 150℃, and subjected to constant temperature and pressure saturation adsorption for 2 hours to allow the supercritical fluid to dissolve uniformly in the TPEE matrix. Subsequently, the pressure is rapidly released at a rate of 1 MPa / min to trigger matrix foaming. During the foaming process, the low-melting-point foamed TPU fully melts and forms a uniform closed-cell structure under the action of high-pressure supercritical carbon dioxide. The fiber web's melting temperature is higher than the foaming temperature, maintaining a solid continuous network skeleton throughout the process without melting, collapse, or deformation. After foaming, the fiber web is completely embedded inside the foamed polymer matrix, which can significantly improve the tear resistance, support stability, and resilience durability of the cushioning material.

[0034] 4. Shaping and post-processing: After foaming, the semi-finished product is transferred to a hot pressing mold and hot-pressed for 15 minutes at 110℃ and 5 MPa. After cooling and demolding, it is cut and trimmed to obtain the target sports shoe midsole.

[0035] 5. Performance Results: The resulting midsole forms a two-layer fiber web internally. After foaming, the pore diameter is 50-150 μm, and the closed-cell rate is 92%. The planar expansion ratio is approximately 1.7 times, and the thickness expansion ratio is approximately 2.2 times. The fiber web is wrinkle-free, without any shift, and is uniformly distributed within the matrix. The density of this midsole is 0.12 g / cm³. 3 With a rebound rate of 83% and a compression set of 8%, it is 40% lighter and has significantly improved rebound and durability compared to traditional EVA midsoles.

[0036] Example 2: Fiber-reinforced supercritical foam cushioning material for sports protective gear pads This embodiment describes the preparation of a fiber-reinforced cushioning pad for sports protective gear, following the steps below: 1. Fiber web preparation: PLA (Fengyuan FY602) fiber web is prepared by melt-blowing process. The melting temperature of this type of PLA is 152℃. The process parameters are controlled to make the fiber diameter 15 μm, the fiber web porosity 80%, and the initial thickness 0.8 mm. Cut to 0.5 times the plane size of the target protective pad after foaming and set aside.

[0037] 2. Raw material proportioning and loading: Weigh the above-mentioned PLA fiber mesh and BASF 1185A foamed TPU matrix particles at a mass ratio of 10:90, with a melting temperature of 185℃. Lay the fiber mesh in layers in the mold, filling the gaps between each layer with TPU particles. After lamination, load the mixture into a supercritical foaming reactor and seal it.

[0038] 3. Supercritical foaming process: Supercritical N2 medium is introduced into the reactor, pressurized to 12 MPa, heated to 110℃, and saturated adsorption is carried out at constant temperature and pressure for 3 h to allow the supercritical fluid to dissolve uniformly in the TPU matrix.

[0039] 4. Shaping and post-processing: After foaming, the semi-finished product is transferred to a hot pressing mold and hot-pressed for 20 minutes at 100℃ and 3 MPa. After cooling and demolding, it is cut and trimmed to obtain the target sports protective pad.

[0040] 5. Performance Results: The resulting protective pad forms a three-layer fiber network internally. After foaming, the pore diameter is 30–200 μm, and the closed-cell rate is 88%. The planar expansion ratio is approximately 1.9 times, and the thickness expansion ratio is approximately 2.5 times. The fiber network is uniformly distributed within the matrix without aggregation or displacement. The density of this protective pad is 0.15 g / cm³. 3 With an impact energy absorption rate of 67% and a compression set of 9.5%, it combines lightweight and impact resistance, effectively reducing the risk of sports injuries.

[0041] Example 3: Fiber-reinforced supercritical foam cushioning material for automotive seat cushioning layers The fiber-reinforced cushioning layer for automotive seats is prepared in this embodiment, and the steps are as follows: TPEE (DuPont Hytrel 4056) fiber web was prepared using electrospinning. The melting point of this type of TPEE fiber web is 152℃, and the electrospinning temperature is controlled at 192℃. The process parameters were controlled to achieve a fiber diameter of 30 μm, a fiber web porosity of 90%, and an initial thickness of 1.0 mm. The web was then cut to 0.7 times the planar dimensions of the target buffer layer after foaming and set aside for later use.

[0042] For raw material proportioning and loading, the above-mentioned TPEE fiber web and TPEE matrix particles are weighed at a mass ratio of 5:95. The melting temperature of the matrix particles is 122℃. The fiber web is laid flat in the mold, and then the TPEE particles are evenly filled into the pores of the fiber web. After compounding, it is loaded into a supercritical foaming reactor and sealed.

[0043] 3. Supercritical foaming process: Supercritical CO2 medium is introduced into the reactor, pressurized to 18 MPa, heated to 130℃, and saturated adsorption is carried out at constant temperature and pressure for 2.5 h to allow the supercritical fluid to dissolve uniformly in the TPEE matrix; then the pressure is rapidly released at a rate of 1.5 MPa / min to trigger matrix foaming.

[0044] 4. Shaping and post-processing: After foaming, the semi-finished product is transferred to a hot pressing mold and hot-pressed for 25 minutes at 120℃ and 6 MPa. After cooling and demolding, it is cut and trimmed to obtain the target car seat cushioning layer.

[0045] 5. Performance Results: The resulting buffer layer forms a single fiber web within the matrix. After foaming, the pore diameter is 80–200 μm, with a closed-cell rate of 90%. The planar expansion ratio is approximately 2.1 times, and the thickness expansion ratio is approximately 2.8 times. The fiber web is wrinkle-free, non-shifted, and uniformly distributed within the matrix. The density of this buffer layer is 0.18 g / cm³. 3 It has a resilience rate of 76%, a compression set of 8.5%, and a temperature resistance that meets the requirements of automotive use environments ranging from -40℃ to 85℃. It shows no significant collapse after long-term use and has excellent durability.

[0046] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a cushioning product, characterized in that, Includes the following steps: The fiber web is mixed with a polymer matrix and subjected to supercritical foaming to obtain the cushioning product. The melting point of the fiber web is higher than the temperature of supercritical foaming, and the temperature of supercritical foaming is higher than the melting point of the polymer matrix. The planar dimensions of the fiber web are 0.4 to 0.8 times the planar dimensions of the cushioning product; the thickness of the fiber web is 0.1 to 2 mm. The mass of the fiber web is 3 to 15% of the total mass of the fiber web and the polymer matrix.

2. The preparation method according to claim 1, characterized in that, The porosity of the fiber web is 60-90%, and the diameter of the fibers in the fiber web is 1-100 μm.

3. The preparation method according to claim 1, characterized in that, The method for preparing the fiber web includes: electrospinning or meltblowing the fiber web raw material; The polymer matrix is ​​one or both of TPU and TPEE.

4. The preparation method according to claim 1 or 3, characterized in that, The melting point of the fiber web is 180~260℃, and the melting point of the polymer matrix is ​​100~150℃.

5. The preparation method according to claim 1 or 3, characterized in that, The supercritical foaming process includes sequential saturation adsorption and pressure relief foaming. The gas used in the supercritical foaming includes supercritical carbon dioxide or supercritical nitrogen.

6. The preparation method according to claim 5, characterized in that, The saturation adsorption temperature is 80~160℃, the pressure is 8~30MPa, and the time is 1~4h; the depressurization rate of the depressurization foaming is 0.5~5MPa / min.

7. The preparation method according to claim 1, characterized in that, After supercritical foaming is completed, the resulting billet is hot-pressed for shaping; the hot-pressing temperature is 90~150℃, the pressure is 2~10MPa, and the holding time is 5~30min.

8. The cushioning article prepared by the method according to any one of claims 1 to 7, characterized in that, Includes a foamed polymer matrix and a fiber network dispersed and embedded within the foamed polymer matrix; The foamed polymer matrix has a cell diameter of 10~300μm and a closed-cell rate of >80%.

9. The cushioning article according to claim 8, characterized in that, The fiber web has ≥2 layers, and adjacent fiber webs are arranged in parallel with equal spacing, with an interlayer spacing of 0.5~5mm.

10. The use of the cushioning article of claim 8 or 9 in footwear materials, sports protective gear, car seats, mattresses, cushions or packaging materials.