THERMOPLASTIC MICRO-SAC POLYMER ELASTOMER MATERIAL AND PREPARATION METHOD THEREFOR

Abstract

A thermoplastic polyurethane elastomer material with micro air holes and preparation thereof are provided. The formula of the thermoplastic polyurethane elastomer material with micro air holes comprises the following ingredients in percentage by weight: 0.1-97% of support polymer material, 0.1-97% of pressure-resistant slow-rebound polymer material, 0.01-0.5% of nucleator and 0.1-10% of foaming agent. The support polymer material is a polymer material with a high molecular weight, high hardness, high crystallization or high polarity. The pressure-resistant slow-rebound polymer material is a polymer material with a low molecular weight, low hardness, crystallization as low as to amorphous state or low polarity/no polarity, corresponding to the support polymer material.

Claims

1. A thermoplastic polymer elastomer material with micro air holes, comprising the following ingredients in percentage by weight: 0.1-97% of a support polymer material, 0.1-97% of a pressure-resistant slow-rebound polymer material, 0.01-0.5% of a nucleator and 0.1-10% of a foaming agent.

2. The thermoplastic polymer elastomer material with micro air holes according to claim 1, wherein the support polymer material is a polymer material with a high molecular weight, high hardness, high crystallization or high polarity, and the pressure-resistant slow-rebound polymer material is a polymer material with a low molecular weight, low hardness, crystallization as low as to amorphous state and a polarity as low as to no polarity, corresponding to the support polymer material.

3. The thermoplastic polymer elastomer material with micro air holes according to claim 2, wherein the support polymer material is a macromolecular weight thermoplastic polyurethane, and the corresponding pressure-resistant slow-rebound polymer material is a low-molecular weight thermoplastic polyurethane; the support polymer material is a high-hardness thermoplastic polymer elastomer, and the corresponding pressure-resistant slow-rebound polymer material is a low-hardness thermoplastic polymer elastomer; or the support polymer material is a polyamide or polyester, and the corresponding pressure-resistant slow-rebound polymer material is a thermoplastic polyurethane.

4. The thermoplastic polymer elastomer material with micro air holes according to claim 3, wherein a molecular weight of the macromolecular weight thermoplastic polyurethane is 810.sup.4510.sup.5, and a molecular weight of the low-molecular weight thermoplastic polyurethane is 210.sup.42.510.sup.5; a shore hardness of the high-hardness thermoplastic polymer elastomer is in a range of 80A to 75D, and a shore hardness of the low-hardness thermoplastic polymer elastomer is in a range of 30 to 85A; the polyester or polyamide is a modified low-melting-point polyester or modified low-melting-point polyamide, and the difference between melting points of the support polymer material and the pressure-resistant slow-rebound polymer material is controlled to be within 20 C. .

5. The thermoplastic polymer elastomer material with micro air holes according to claim 1, wherein the nucleator is selected from at least any one of carbon nano-tube, silicon dioxide, talcum powder, modified calcium carbonate, carbon black and tetrafluoroethylene powder ; and the foaming agent is selected from at least any one of CO2, N2, normal butane, n-pentane and isopentane.

6. The thermoplastic polymer elastomer material with micro air holes according to claim 1, wherein the polymer elastomer material is uniform spherical particles with a particle size in a range of 0.6 to 25 mm.

7. A method for preparing the thermoplastic polyurethane elastomer material with micro air holes according to claim 1, comprising following steps: (1) feeding the support polymer material, the pressure-resistant slow-rebound polymer material and the nucleator into a double-screw extruder via a feeding port at a front end, feeding the foaming agent into the double-screw extruder via a feeding port in the middle section, melting and well mixing all raw materials, sending the mixed materials into a static mixer for further homogenization to obtain a hot melt, and delivering the hot melt by a melt pump under a controlled pressure and at a fixed amount; (2) guiding the hot melt that is delivered by the melt pump to pass a mold head and enter an underwater granulation chamber to obtain particles, delivering and separating the particles by process water, screening and drying the particles to obtain the thermoplastic polyurethane elastomer material with micro air holes.

8. The method for preparing the thermoplastic polyurethane elastomer material with micro air holes according to claim 7, wherein in step (1), a temperature of the double-screw extruder is in a range of 160 to 300 C.; a length-diameter ratio of the double-screw extruder is 32:56; a temperature in the static mixer is set to be in a range of 120 to 280 C.; an inlet pressure of the melt pump is in a range of 50 to 200 bar; and the difference between a pressure of the hot melt extruded via the mold head and a pressure of the process water in the underwater granulation chamber is controlled to be in a range of 70 to 120 bar.

9. The method for preparing the thermoplastic polyurethane elastomer material with micro air holes according to claim 7, wherein in step (2), the process water in the underwater granulation chamber is at a temperature in a range of 10 to 90 C. and under a pressure in a range of 4 to 15 bar; the particles are brought out of the underwater granulation chamber and delivered by the process water via a multi-stage pressure-release expansion process water pipeline of which the pressure gradually drops.

10. The method for preparing the thermoplastic polyurethane elastomer material with micro air holes according to claim 9, wherein in step (2), the multi-stage pressure-release expansion process water pipeline is a multi-stage process water pipeline, wherein a water pressure of a first-stage process water pipe keeps consistent with the process water pressure in the underwater granulation chamber.

11. A method for preparing the thermoplastic polyurethane elastomer material with micro air holes according to claim 2, comprising following steps: (1) feeding the support polymer material, the pressure-resistant slow-rebound polymer material and the nucleator into a double-screw extruder via a feeding port at a front end, feeding the foaming agent into the double-screw extruder via a feeding port in the middle section, melting and well mixing all raw materials, sending the mixed materials into a static mixer for further homogenization to obtain a hot melt, and delivering the hot melt by a melt pump under a controlled pressure and at a fixed amount; (2) guiding the hot melt that is delivered by the melt pump to pass a mold head and enter an underwater granulation chamber to obtain particles, delivering and separating the particles by process water, screening and drying the particles to obtain the thermoplastic polyurethane elastomer material with micro air holes.

12. A method for preparing the thermoplastic polyurethane elastomer material with micro air holes according to claim 3, comprising following steps: (1) feeding the support polymer material, the pressure-resistant slow-rebound polymer material and the nucleator into a double-screw extruder via a feeding port at a front end, feeding the foaming agent into the double-screw extruder via a feeding port in the middle section, melting and well mixing all raw materials, sending the mixed materials into a static mixer for further homogenization to obtain a hot melt, and delivering the hot melt by a melt pump under a controlled pressure and at a fixed amount; (2) guiding the hot melt that is delivered by the melt pump to pass a mold head and enter an underwater granulation chamber to obtain particles, delivering and separating the particles by process water, screening and drying the particles to obtain the thermoplastic polyurethane elastomer material with micro air holes.

13. A method for preparing the thermoplastic polyurethane elastomer material with micro air holes according to claim 4, comprising following steps: (1) feeding the support polymer material, the pressure-resistant slow-rebound polymer material and the nucleator into a double-screw extruder via a feeding port at a front end, feeding the foaming agent into the double-screw extruder via a feeding port in the middle section, melting and well mixing all raw materials, sending the mixed materials into a static mixer for further homogenization to obtain a hot melt, and delivering the hot melt by a melt pump under a controlled pressure and at a fixed amount; (2) guiding the hot melt that is delivered by the melt pump to pass a mold head and enter an underwater granulation chamber to obtain particles, delivering and separating the particles by process water, screening and drying the particles to obtain the thermoplastic polyurethane elastomer material with micro air holes.

14. A method for preparing the thermoplastic polyurethane elastomer material with micro air holes according to claim 5, comprising following steps: (1) feeding the support polymer material, the pressure-resistant slow-rebound polymer material and the nucleator into a double-screw extruder via a feeding port at a front end, feeding the foaming agent into the double-screw extruder via a feeding port in the middle section, melting and well mixing all raw materials, sending the mixed materials into a static mixer for further homogenization to obtain a hot melt, and delivering the hot melt by a melt pump under a controlled pressure and at a fixed amount; (2) guiding the hot melt that is delivered by the melt pump to pass a mold head and enter an underwater granulation chamber to obtain particles, delivering and separating the particles by process water, screening and drying the particles to obtain the thermoplastic polyurethane elastomer material with micro air holes.

15. A method for preparing the thermoplastic polyurethane elastomer material with micro air holes according to claim 6, comprising following steps: (1) feeding the support polymer material, the pressure-resistant slow-rebound polymer material and the nucleator into a double-screw extruder via a feeding port at a front end, feeding the foaming agent into the double-screw extruder via a feeding port in the middle section, melting and well mixing all raw materials, sending the mixed materials into a static mixer for further homogenization to obtain a hot melt, and delivering the hot melt by a melt pump under a controlled pressure and at a fixed amount; (2) guiding the hot melt that is delivered by the melt pump to pass a mold head and enter an underwater granulation chamber to obtain particles, delivering and separating the particles by process water, screening and drying the particles to obtain the thermoplastic polyurethane elastomer material with micro air holes.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG. 1 is a process flowchart of the disclosure;

[0043] FIG. 2-4 are SEM pictures in different scales of the interior of the polymer elastic material with micro air holes prepared by the disclosure;

[0044] FIG. 5-8 are SEM pictures in different scales of the surface of the polymer elastic material with micro air holes prepared by the disclosure;

[0045] In the drawings, 1motor; 2double-screw extruder; 3feeding port I; 4feeding port II; 5static mixer; 6melt pump; 7mold head; 8underwater granulation chamber; 9process water inlet pipe; 10first-stage process water pressure release pipe; 11second-stage process water pressure release pipe; 12third-stage process water pressure release pipe; 13fourth-stage process water pressure release pipe; 14centrifugal separator; 15vibrating screen; 16process water pump.

DETAILED DESCRIPTION

[0046] The disclosure is further described in detail in conjunction with the attached drawings and specific embodiment.

[0047] It is necessary to point out that the following embodiment is intended only for further describing the disclosure and cannot be understood as limitations to the protective scope of the disclosure. Those skilled in this field can make some non-essential improvements and adjustments according to the content of the disclosure, which shall still fall within the protective scope of the disclosure.

[0048] Besides, unless otherwise specified, all raw materials are commercially available.

[0049] The contents of the disclosure can be more easily understood by referring to the detailed description of the preferable implementation methods and inclusive embodiment of the disclosure below. Unless otherwise specified, all technologies and scientific terms used in this text have meanings that can be generally understood by the ordinarily skilled in the field. If contradictions arise, the definition in the Description shall prevail.

[0050] For example, terms is prepared by and comprising used in this text are synonymous. Terms including, comprising, having and containing or any other modifications used in this text are intended for non-exclusive inclusion. For example, compositions, procedures, methods, products or devices including listed factors are not necessarily limited to the factors, but can include all other unlisted factors, or their inherent factors.

[0051] When values, concentrations, or other values or parameters are expressed by a scope, a preferable scope, or a scope defined by a series of upper preferred values and lower preferred values, this should be understood as that all scopes defined by any match of an upper limit in any scope or a preferred value and a lower limit in any scope or a preferred value are specifically disclosed, regardless of whether or not the scopes are individually disclosed. For example, when a scope of 1 to 5 is disclosed, the described scope should be understood to include a scope of 1 to 4, a scope of 1 to 3, a scope of 1 to 2, a scope of 1 to 2 and 4 to 5, a scope of 1 to 3 and 5, etc. When the scope of a numerical value is described in this text, unless otherwise specified, the scope is intended for including end values and all integers and fractions in this scope.

[0052] Approximate words used in the Description and the Claims are adjuncts of the quantifier, indicating that the disclosure is not limited to the specific quantity, but also includes acceptable revision portions which approach the quantity, but do not cause changes in the relevant basic functions. Correspondingly, approximate and about are adjuncts of a numerical value, meaning that the disclosure is not limited to the accurate numerical value. In some cases, approximation words may be corresponding to the accuracy of instruments for measuring the numerical values. In the Description and Claims of the present application, scope definitions can be combined and/or exchanged. Unless otherwise specified, each of those scopes includes all sub-scopes there-between.

[0053] In addition, indefinite articles a and an in front of the factors or ingredients in the disclosure do not limit the quantity of the factors or ingredients. Therefore, a and an should be understood to include one or at least one, and a singular factor or ingredient also includes the plural form, unless the described number obviously indicates the singular form.

[0054] Polymer refers to a polymer compound prepared by polymerizing identical or different types of monomers. The general term polymer contains terms homopolymer, co-polymer, terpolymer and interpolymer.

[0055] The disclosure provides a thermoplastic polymer elastomer material with micro air holes, including the following ingredients in percentage by weight: 0.1-97% of support polymer material, 0.1-97% of pressure-resistant slow-rebound polymer material, 0.01-0.5% of nucleator and 0.1-10% of foaming agent.

[0056] As a preferable implementation solution, the support polymer material is a polymer material with a high molecular weight, high hardness, high crystallization or high polarity, and the pressure-resistant slow-rebound polymer material is a polymer material with a low molecular weight, low hardness, crystallization as low as to amorphous state and low polarity/no polarity, corresponding to the support polymer material.

[0057] As a more preferable option of the above preferable implementation solution, the support polymer material is macromolecular weight polyurethane, and the corresponding pressure-resistant slow-rebound polymer material is low-molecular weight polyurethane;

[0058] or the support polymer material is high-hardness thermoplastic polymer elastomer (TPU, TPE, or rubber, etc. selected upon actual situations), and the corresponding pressure-resistant slow-rebound polymer material is low-hardness thermoplastic polymer elastomer;

[0059] or the support polymer material is polyamide or polyester, and the corresponding pressure-resistant slow-rebound polymer material is thermoplastic polyurethane.

[0060] As a further preferable option of the above more preferable implementation solution, the molecular weight Mw of the macromolecular weight polyurethane is 810.sup.4510.sup.5, and the molecular weight Mw of the low-molecular weight polyurethane is 210.sup.42.510.sup.5;

[0061] the shore hardness of the high-hardness thermoplastic polymer elastomer is in a range of 80A to 75 D; the shore hardness of the low-hardness thermoplastic polymer elastomer is in a range of 30 to 85A;

[0062] the polyester or polyamide is modified low-melting-point polyester or modified low-melting-point polyamide, and the difference between the melting points of the support polymer material and the pressure-resistant rebound polymer material is controlled to be within 20 C. More preferably, the modified low-melting-point polyester may be modified PET, PTT, or PBT, and the modified low-melting-point polyamide may be modified low-melting-point PA6, PA6I, PA11, PA12, or PA9.

[0063] As a preferable implementation solution, the nucleator is selected from at least any one of carbon nano-tube, silicon dioxide, talcum powder, modified calcium carbonate, carbon black and tetrafluoroethylene powder;

[0064] and the foaming agent is selected from at least any one of CO2, N2, normal butane, n-pentane and isopentane.

[0065] As a preferable solution, the particle size of the polymer elastomer material is in a range of 0.6 to 25 mm.

[0066] Besides, it needs to be noted that the formula disclosed above is merely a basic formula of the disclosure. On the basis of the basic formula disclosed by the disclosure, those skilled in this field can add other conventional auxiliaries into the formula, for example, antioxidants and anti-aging agents which can improve the anti-aging performance of the product.

[0067] The disclosure also provides a method for preparing a thermoplastic elastomer material with micro air holes, including the following steps:

[0068] (1) feeding the support polymer material, the pressure-resistant slow-rebound polymer material and the nucleator into a double-screw extruder via a feeding port at the front end, feeding the foaming agent into the double-screw extruder via a feeding port in the middle section, melting and well mixing all raw materials, sending the mixed materials into a static mixer for further homogenization to obtain a hot melt, and delivering the hot melt by a melt pump under a controlled pressure and at a fixed amount;

[0069] (2) guiding the hot melt that is delivered by the melt pump to pass a mold head and enter an underwater granulation chamber to obtain particles, delivering and separating the particles by process water, screening and drying the particles to obtain the target product.

[0070] As a preferable implementation solution, in step (1), the temperature of the double-screw extruder is in a range of 160 to 300 C., and the length-diameter ratio of the double-screw extruder is 32:56;

[0071] the temperature in the static mixer is set to be in a range of 120 to 280 C.; the inlet pressure of the melt pump meets the following requirement: the pressure of the hot melt extruded via the mold head and the pressure of the process water in the underwater granulation chamber is in a range of 70 to 120 bar.

[0072] As a preferable implementation solution, the process water in the underwater granulation chamber in step (2) is at a temperature in a range of 10 to 90 C. and under a pressure in a range of 4 to 15 bar.

[0073] The particles are brought out of the underwater granulation chamber and delivered by the process water via a multi-stage pressure-release expansion process water pipeline of which the pressure gradually drops.

[0074] As a further preferable option of the above preferable implementation solution, in step (2), the multi-stage pressure-release expansion process water pipeline is a four-stage process water pipeline, wherein the water pressure is 4-15 bar in the first-stage process water pipe, 3-10 bar in the second-stage process water pipe, 2-6 bar in the third-stage process water pipe, and 1-4 bar in the fourth-stage process water pipe.

[0075] Further preferably, the details of the above preparation process can be seen in FIG. 1, wherein the double-screw extruder 2 is driven by a motor 1 to rotate at a speed in a range of 50 to 900 rpm; a screw barrel of the double-screw extruder 2 is preferably set at a temperature in a range of 160 to 300 C. to ensure that the thermoplastic polymer can be fully melted; the polymer raw materials and the nucleator are fed via a screw feeding port I 3 at the front end, and the foaming agent is fed via a screw feeding port II 4 in the middle section. The mixed materials are heated and sheared by screws, so that all raw materials are melted and well mixed by the screws to generate a melt which subsequently enters the static mixer. The melt is further homogenized and cooled in the static mixer 5 to ensure that the melt temperature is in a range of 120 to 280 C. The temperature can be controlled upon requirements for physical properties of the finished product. Through the pressure control and fixed-amount delivery functions of the melt pump 6 (a gear pump can be adopted), the inlet pressure of the melt pump 6 is set to be in a range of 50 to 200 bar to control the melt pressure in a screw cavity of the double-screw extruder 2 to keep stable, so that the hot melt, the nucleator and the foaming agent can be well mixed and homogenized in a controllable high-pressure environment. The high-pressure hot melt is steadily pushed into the mold head 7 of the extruder 7 through the pressure control and fixed-amount delivery functions of the melt pump 6, wherein the mold heat 7 is of a porous plate structure with a uniform heating facility inside to ensure that the hot melt can steadily pass the mold head 7. The hot melt delivered by the melt pump 6 at a high pressure passes orifices of the mold head 7, and then is granulated into soybean-shaped particles by a granulation cutter which is rotating at a high speed in the underwater granulation chamber 8, wherein the granulation cutter of the underwater granulation chamber 8 actually granulates hot melt under water. The process water at a temperature in a range of 10 to 90 C. generates a 4-15 bar pressure by the effect of a process water pump assembly (16) (including the water pump, a water tank, etc.), and enters the underwater granulation chamber 8 via a process water inlet pipe 9 of the underwater granulation chamber. In this way, the high-pressure hot melt extruded via the mold head 7 is quickly cooled by the high-pressure process water and is granulated by the granulation cutter. The high-pressure hot melt and the high-pressure process water generate a differential pressure which can be regulated according to the inlet pressure of the melt pump 6 and the pressure output by the process water pump assembly 16, so that the initial expansion rate and factor of the polymer particles are under control and keep stable in the whole process. Since the cooling time of the just granulated polymer particles is short and the material crystallization speed varies a lot in different formulas, the disclosure specially adopts a multi-stage pressure-release expansion process water pipeline (a four-stage pipeline is preferably adopted here). Based on the principle that the strength and the pressure bearing conditions increase as the outer surfaces of the polymer particles stay in process water for a longer time, the pressure is still maintained in a range of 4 to 15 bar in the first-stage process water pipeline (namely the first-stage process water pipe 10), and in such circumstance, the melt particles are partly cooled and initially expand under a differential pressure. In the second-stage process water pipeline (namely the second-stage process water pipe 11), the water pressure is lowered to 3-10 bar through increasing the pipeline diameter and shortening the pipeline. In such circumstance, the melt particles are further cooled, and the strength of the outer surfaces increases, but expansion occurs again after the differential pressure increases. In the third-stage process water pipeline (namely the third-stage process water pipe 12), the pipe resistance is reduced through increasing the pipe diameter and shortening the pipe to lower the water pressure to 2-6 bar. In such circumstance, the melt particles are further cooled, and the strength of the outer surfaces increases, but expansion occurs again after the differential pressure increases. However, the expansion rate drops to a very low level because particle crystallization is about be completed. In the fourth-stage process water pipeline (namely the fourth-stage process water pipe 13), the pipe resistance is reduced by regulating the pipe diameter and length to lower the water pressure to 1-4 bar. In such circumstance, the melt particles are continuously cooled, and the strength of the outer surfaces is enhanced, but expansion occurs again after the differential pressure increases. However, due to sufficient cooling time, the very high strength of the outer surfaces of the particles and basically completed particle crystallization, the outer diameters of the particles are firmly finalized. The expanded polymer particles and water jointly enter a centrifugal separator 14. The water and the expanded polymer particles are separated in the separator. The expanded particles enter a vibrating screen 15 and then a post-treatment system and finally are output as an expanded product, and the process water flows out of the centrifugal separator 14 and then flows into a process water pump assembly 16. The above procedures are repeated so that the process proceeds continuously.

[0076] In addition, it needs to be pointed out that, the above preparation method is a preferable process of the disclosure for preparing the compound bubble hole structure with open and closed holes. Besides the above-mentioned preferable process which adopts screws for continuous foaming, the disclosure can also adopt other conventional foaming preparation processes such as reactor foaming on the basis of a basic formula which can generate multiple bubble hole structures, and the finally obtained products also have the compound bubble hole structure with open and closed holes.

[0077] In the following embodiment, raw materials used include: polyether type and polyester type thermoplastic polyurethane from Bayer and Huntsman, modified low-melting-point PET and PBT from Sinopec Shanghai Petrochemical Company Limited, and modified low-melting-point polyamide from DuPont and Evonik.

Embodiment 1

[0078] According to the process flow as shown in FIG. 1, a thermoplastic polymer elastomer material with micro air holes of the disclosure was prepared based on the following raw material formula and process conditions:

[0079] In this embodiment, the raw materials added in percentage by weight included: 75% of polyether type thermoplastic polyurethane with a molecular weight Mw in a range of 150K to 300K (K means the unit thousand here, the same below), 20% of polyether type thermoplastic polyurethane with a molecular weight Mw in a range of 50K to 100K, 4.5% of foaming agent which was CO2, and 0.5% of nucleator which was calcium carbonate. The length-diameter ratio L/D of the double-screw extruder was 40; the heating temperature of the screws was in a range of 160 to 220 C.; the temperature of the static mixer was in a range of 140-180 C.; the inlet pressure of the melt pump was in a range of 100 to 120 bar; the process water pressure was about 12 bar; and the difference pressure during pressure release (namely the differential pressure between the high-pressure hot melt at the exit of the mold head and the process water in the underwater granulation chamber) was controlled to be in a range of 90 to 120 bar. In the multi-stage pressure-release expansion process water pipeline, the water pressure was controlled to be about 12 bar in the first-stage process water pipe, about 8 bar in the second-stage process water pipe, about 5 bar in the third-stage process water pipe, and about 2 bar in the fourth-stage process water pipe.

[0080] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen had a particle size in a range of about 1 to 3 mm. In the material, the formed micro air hole structure accounted for about 60-80% and the open bubble hole structure accounted for about 10-35% by volume.

[0081] FIGS. 2-4 are SEM pictures in different scales of the interior of the polymer elastomer material with micro air holes prepared in embodiment 1, and from the FIGS., it can be seen that the particle material has an obvious coiled, network-like and cross-linking air channel structure which is formed by micro air holes and open bubble holes. FIGS. 5-8 are SEM pictures in different scales of the surface of the polymer elastomer material with micro air holes prepared in embodiment 1, and from the FIGS., it can be seen that the air channels extend to the surfaces of the particle material.

Embodiment 2

[0082] According to the process flow as shown in FIG. 1, a thermoplastic polymer elastomer material with micro air holes of the disclosure was prepared based on the following raw material formula and process conditions:

[0083] In this embodiment, the raw materials added in percentage by weight included: 60% of polyether type thermoplastic polyurethane with a molecular weight Mw in a range of 300K to 500K (K means the unit thousand here, the same below), 35% of polyether type thermoplastic polyurethane with a molecular weight Mw in a range of 150K to 250K, 4.95% of foaming agent which was N2, and 0.05% of nucleator which was carbon black. The length-diameter ratio L/D of the double-screw extruder was 56; the heating temperature of the screws was in a range of 160 to 220 C.; the temperature of the static mixer was in a range of 140-180 C.; the inlet pressure of the melt pump was in a range of 100 to 150 bar; the process water pressure was about 6 bar; and the differential pressure during pressure release (namely the differential pressure between the high-pressure hot melt at the exit of the mold head and the process water in the underwater granulation chamber) was controlled to be in a range of 90 to 140 bar. In the multi-stage pressure-release expansion process water pipeline, the water pressure was controlled to be about 6 bar in the first-stage process water pipe, about 5 bar in the second-stage process water pipe, about 3 bar in the third-stage process water pipe, and about 1 bar in the fourth-stage process water pipe.

[0084] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen had a particle size in a range of about 8 to 12 mm. In the material, the formed micro air hole structure accounted for about 30-50% and the open bubble hole structure accounted for about 40-60% by volume.

Embodiment 3

[0085] According to the process flow as shown in FIG. 1, a thermoplastic polymer elastomer material with micro air holes of the disclosure was prepared based on the following raw material formula and process conditions:

[0086] In this embodiment, the raw materials added in percentage by weight included: 97% of polyether type thermoplastic polyurethane with a molecular weight Mw in a range of 80K to 120K (K indicates the unit thousand here, the same below), 0.1% of polyether type thermoplastic polyurethane with a molecular weight Mw in a range of 20K to 50K, 2.4% of foaming agent which was N2, and 0.5% of nucleator which was the mixture of talcum powder and modified calcium carbonate in a mass ratio of 1:1. The length-diameter ratio L/D of the double-screw extruder was 46; the heating temperature of the screws was in a range of 160 to 220 C.; the temperature of the static mixer was in a range of 130-170 C.; the inlet pressure of the melt pump was in a range of 120 to 180 bar; the process water pressure was about 15 bar; and the pressure difference of pressure release (namely the differential pressure between the high-pressure hot melt at the exit of the mold head and the process water in the underwater granulation chamber) was controlled to be in a range of 120 to 150 bar. In the multi-stage pressure-release expansion process water pipeline, the water pressure was controlled to be about 15 bar in the first-stage process water pipe, about 10 bar in the second-stage process water pipe, about 6 bar in the third-stage process water pipe, and about 4 bar in the fourth-stage process water pipe.

[0087] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen had a particle size of about 0.6-2 mm. In the material, the formed micro air hole structure accounted for about 30-45% and the open bubble hole structure accounted for about 0.5-10% by volume.

Embodiment 4

[0088] According to the process flow as shown in FIG. 1, a thermoplastic polymer elastomer material with micro air holes of the disclosure was prepared based on the following raw material formula and process conditions:

[0089] In this embodiment, the raw materials added in percentage by weight included: 0.1% of polyether type thermoplastic polyurethane with a molecular weight Mw in a range of 300K to 500K (K means the unit thousand here, the same below), 97% of polyether type thermoplastic polyurethane with a molecular weight Mw in a range of 20K to 50K, 2.8% of foaming agent which was N2, and 0.1% of nucleator which was carbon nano-tube. The length-diameter ratio L/D of the double-screw extruder was 48; the heating temperature of the screws was in a range of 160 to 220 C.; the temperature of the static mixer was in a range of 130-180 C.; the inlet pressure of the melt pump was in a range of 90 to 120 bar; the process water pressure was about 10 bar; and the pressure difference of pressure release (namely the differential pressure between the high-pressure hot melt at the exit of the mold head and the process water in the underwater granulation chamber) was controlled to be in a range of 80 to 120 bar. In the multi-stage pressure-release expansion process water pipeline, the water pressure was controlled to be about 10 bar in the first-stage process water pipe, about 7 bar in the second-stage process water pipe, about 4 bar in the third-stage process water pipe, and about 2 bar in the fourth-stage process water pipe.

[0090] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen had a particle size in a range of about 12 to 25 mm. In the material, the formed micro air hole structure accounted for about 20% and the open bubble hole structure accounted for about 60-70% by volume.

Embodiment 5

[0091] According to the process flow as shown in FIG. 1, a thermoplastic polymer elastomer material with micro air holes of the disclosure was prepared based on the following raw material formula and process conditions:

[0092] In this embodiment, the raw materials added in percentage by weight included: 70% of polyether type thermoplastic polyurethane with a molecular weight Mw in a range of 120K to 180K (K indicates the unit thousand here, the same below), 19.7% of polyether type thermoplastic polyurethane with a molecular weight Mw in a range of 20K to 50K, 10% of foaming agent which was the mixture of CO2 and N2 in a volume ratio of 1:1, and 0.3% of nucleator which was the mixture of calcium carbonate and tetrafluoroethylene powder in a mass ratio of 1:1. The length-diameter ratio L/D of the double-screw extruder was 40; the heating temperature of the screws was in a range of 180 to 240 C.; the temperature of the static mixer was in a range of 140-190 C.; the inlet pressure of the melt pump was in a range of 100 to 120 bar; the process water pressure was about 10 bar; and the differential pressure during pressure release (namely the differential pressure between the high-pressure hot melt at the exit of the mold head and the process water in the underwater granulation chamber) was controlled to be in a range of 90 to 120 bar. In the multi-stage pressure-release expansion process water pipeline, the water pressure was controlled to be about 10 bar in the first-stage process water pipe, about 7 bar in the second-stage process water pipe, about 4 bar in the third-stage process water pipe, and about 2 bar in the fourth-stage process water pipe.

[0093] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen had a particle size in a range of about 3 to 6 mm. In the material, the formed micro air hole structure accounted for about 60% and the open bubble hole structure accounted for about 10% by volume.

Embodiment 6

[0094] Compared with embodiment 1, all were identical, except the raw material formula replaced by the following ingredients in percentage by weight:

[0095] 80% of polyester type thermoplastic polyurethane with a molecular weight Mw in a range of 200K to 300K (K indicates the unit thousand here, the same below), 18.9% of polyester type thermoplastic polyurethane with a molecular weight Mw in a range of 50K to 100K, 1% of foaming agent which was the mixture of CO2 and N2 in a volume ratio of 1:1, and 0.1% of nucleator which was the mixture of calcium carbonate and tetrafluoroethylene powder in a mass ratio of 1:1.

[0096] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen also had a compound bubble hole structure formed by micro air holes (closed holes) and open bubble holes. Refer to the bubble hole structure as shown in FIG. 2-8. In the material, the formed micro air hole structure accounted for about 70-80% and the open bubble hole structure accounted for about 15-30% by volume.

Embodiment 7

[0097] Compared with embodiment 1, all were identical, except the raw material formula replaced by the following ingredients in percentage by weight:

[0098] 80% of polyester type thermoplastic polyurethane with 80A shore hardness, 19.5% of polyester type thermoplastic polyurethane with 30A shore hardness, 0.4% of the foaming agent which was the mixture of CO2 and N2 in weight ratio of 1:1, and 0.1% of nucleator which was the mixture of carbon nano-tube, talcum powder and calcium carbonate.

[0099] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen also had a compound bubble hole structure formed by micro air holes (closed holes) and open bubble holes. Refer to the bubble hole structure as shown in FIG. 2-8. In the material, the formed micro air hole structure accounted for about 70-80% and the open bubble hole structure accounted for about 15-30% by volume.

Embodiment 8

[0100] Compared with embodiment 7, all were identical, except the raw material formula replaced by the following ingredients in percentage by weight:

[0101] 70% of polyester type thermoplastic polyurethane with 75D shore hardness, 27.5% of polyester type thermoplastic polyurethane with 85A shore hardness, 2% of the foaming agent which was the mixture of CO2 and N2 in weight ratio of 1:1, and 0.5% of nucleator which was the mixture of carbon nano-tube, talcum powder and calcium carbonate.

[0102] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen also had a compound bubble hole structure formed by micro air holes (closed holes) and open bubble holes. Refer to the bubble hole structure as shown in FIG. 2-8. In the material, the formed micro air hole structure accounted for about 60-70% and the open bubble hole structure accounted for about 25-40% by volume.

Embodiment 9

[0103] Compared with embodiment 7, all were identical, except the high-hardness polyester type thermoplastic polyurethane with 90A shore hardness and low-hardness polyester type thermoplastic polyurethane with 50A shore hardness as replacements in the raw material formula.

[0104] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen also had a compound bubble hole structure formed by micro air holes (closed holes) and open bubble holes. Refer to the bubble hole structure as shown in FIG. 2-8. In the material, the formed micro air hole structure accounted for about 70-80% and the open bubble hole structure accounted for about 15-30% by volume.

Embodiment 10

[0105] According to the process flow as shown in FIG. 1, a thermoplastic polymer elastomer material with micro air holes of the disclosure was prepared based on the following raw material formula and process conditions:

[0106] In this embodiment, the raw materials added in percentage by weight included: 60% of modified low-melting-point PET, 37% of polyester type polyurethane (the difference between the melting points of the modified low-melting point PET and the polyester type polyurethane was 20 C.), 0.5% of nucleator which was carbon black, and 2.5% of foaming agent which was the mixture of CO2 and N2.

[0107] The length-diameter ratio L/D of the double-screw extruder was 52; the heating temperature of the screws was in a range of 220 to 280 C.; the temperature of the static mixer was in a range of 160-200 C.; the inlet pressure of the melt pump was in a range of 100 to 150 bar; the process water pressure was about 15 bar; and the differential pressure during pressure release (namely the differential pressure between the high-pressure hot melt at the exit of the mold head and the process water in the underwater granulation chamber) was controlled to be in a range of 130 to 180 bar. In the multi-stage pressure-release expansion process water pipeline, the water pressure was controlled to be about 15 bar in the first-stage process water pipe, about 12 bar in the second-stage process water pipe, about 8 bar in the third-stage process water pipe, and about 4 bar in the fourth-stage process water pipe.

[0108] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen also had a compound bubble hole structure formed by micro air holes (closed holes) and open bubble holes. Refer to the bubble hole structure as shown in FIG. 2-8. In the material, the formed micro air hole structure accounted for about 50-80% and the open bubble hole structure accounted for about 5-50% by volume.

Embodiment 11

[0109] Compared with embodiment 10, all were identical, except the modified low-melting-point polyaminde (PA) which replaced the modified low-melting-point PET.

[0110] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen also had a compound bubble hole structure formed by micro air holes (closed holes) and open bubble holes. Refer to the bubble hole structure as shown in FIG. 2-8. In the material, the formed micro air hole structure accounted for about 50-80% and the open bubble hole structure accounted for about 5-50% by volume.

Embodiment 12

[0111] Compared with embodiment 10, all were identical, except the PBT which replaced the modified low-melting-point PET.

[0112] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen also had a compound bubble hole structure formed by micro air holes (closed holes) and open bubble holes. Refer to the bubble hole structure as shown in FIG. 2-8. In the material, the formed micro air hole structure accounted for about 50-80% and the open bubble hole structure accounted for about 5-50% by volume.

Embodiment 13-15

[0113] Compared with embodiment 1, all were identical, except the n-butane, n-pentane and iso-pentane, which respectively served as the foaming agent.

[0114] In embodiment 13-15, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen also had a compound bubble hole structure formed by micro air holes (closed holes) and open bubble holes. Refer to the bubble hole structure as shown in FIG. 2-8.

Embodiment 16

[0115] Compared with embodiment 1, all were identical in this embodiment, except the procedure of directly bringing out the particles in the underwater granulation chamber by the process water at a basically stable pressure in a range 40 to 50 C. of and under a basically stable pressure in a range of 4 to 8 bar, and the procedures of pressure release, cooling and molding.

[0116] Finally, the thermoplastic polymer elastomer material with micro air holes obtained using the vibrating screen also had a compound bubble hole structure formed by micro air holes (closed holes) and open bubble holes. Refer to the bubble hole structure as shown in FIG. 2-8. However, compared with the foam particles in embodiment 1, some of the foam particles in this embodiment had breaking bubble holes.

Embodiment 17

[0117] Compared with embodiment 1, a conventional reactor foaming process at a foaming temperature of about 150 C. and under a pressure of about 15 Mpa was adopted in this embodiment.

[0118] Finally, the prepared foam particles also had the compound bubble hole structure formed by micro air holes (closed hole) and open bubble holes, like the foam particles as shown in FIG. 1-8, but the bubble holes were relatively unstable and tend to collapse.

COMPARISON EXAMPLE 1

[0119] Compared with embodiment 1, all were identical in this example, except that all the polymer raw material was polyether type thermoplastic polyurethane with a molecular weight in a range of 150K to 300K .

COMPARISON EXAMPLE 2

[0120] Compared with embodiment 7, all were identical in this example, except that all the polymer raw material was polyester type thermoplastic polyurethane with 80A shore hardness.

COMPARISON EXAMPLE 3

[0121] Compared with embodiment 10, all were identical in this example, except that all the polymer raw material was modified low-melting-point PET (which means that no polyester type polyurethane was added).

[0122] Finally, the foaming materials prepared in comparison examples 1-3 were tested to analyze the bubble holes thereof. Results showed that all foaming materials obtained in the three comparison examples were foam particles with continuous surfaces, and the inner scanning pictures of the cut particles showed that all bubble holes were closed holes, without the open holes which extended to the surfaces, like the foam particles obtained in embodiment 1 as shown in FIG. 5-8. Besides, the foaming factor was obviously smaller than that of the formula which contains two kinds of mixed polymer raw materials.

[0123] From the above embodiment and comparison examples it can be known that, in comparison with the comparison examples which used a single polymer as the raw material to prepare foam particles with pure closed holes, the disclosure, through improving the formula of the foam particles, adopts two kinds of polymers of different physical conditions as the raw materials to prepare the foam particles with a compound bubble hole structure which is formed by open and closed holes, in conjunction with the principle that the foaming agent has different foaming capabilities in two kinds of polymers during the foaming process.

[0124] The above embodiment is illustrative, intended for explaining some characteristics of the method of the disclosure. The attached claims are aimed to define a protective scope as wide as possible, and the embodiment described in this text merely illustrates combinational preferable implementation solutions according to all possible embodiment. Therefore, the attached claims cannot be limited by the above embodiment options of the characteristics of the disclosure. Some scopes of the numerical values in the claims also include their sub-scopes, and changes in such scopes shall also fall within the protective scope of the claims.