POLYMER FOAMED FIBER, AND PREPARATION METHOD AND USE THEREOF

Abstract

Provided are a polymer foamed fiber and a preparation method thereof. The polymer foamed fiber has a closed-pore structure in an interior, the closed-pore structure comprises uniform and dense pores and an average pore size of the pores in the closed-pore structure is in a range of from 1 m to 50 m. The polymer foamed fiber has a diameter in a range of from 0.08 mm to 1.0 mm with an average deviation of the diameter of 0.05 mm, a skin layer thickness in a range of from 0 to 0.1 mm, a density in a range of from 0.30 g/cm.sup.3 to 0.90 g/cm.sup.3, and an elongation at break in a range of from 0 to 600%. The polymer foamed fiber has advantages, such as, light weight, uniform fiber thickness, a porous structure, dense internal pores with uniform pore sizes and a controllable skin layer thickness.

Claims

1. A polymer foamed fiber, wherein the polymer foamed fiber has a closed-pore structure in an interior, the closed-pore structure comprises uniform and dense pores and an average pore size of the pores in the closed-pore structure is in a range of from 1 m to 50 m; a diameter of the polymer foaming fiber is in a range of from 0.08 mm to 1.0 mm with an average deviation of the diameter of 0.05 mm, a skin layer thickness of the polymer foamed fiber is in a range of from 0 to 0.1 mm, a density of the polymer foamed fiber is in a range of from 0.30 g/cm.sup.3 to 0.90 g/cm.sup.3, and an elongation at break of the polymer foamed fiber is in a range of from 0 to 600%.

2. The polymer foamed fiber according to claim 1, wherein the polymer foamed fiber comprises following components in parts by weight: 90-100 parts of a polymer, 1-10 parts of a nucleating agent, 0-1 parts of a chain extender, and 0-0.5 parts of an antioxidant.

3. The polymer foamed fiber according to claim 2, wherein the polymer foamed fiber satisfies at least one of following items: (1) a melting point of the polymer is in a range of from 100 C. to 230 C. and a hardness of the polymer is in a range of from Shore 60A to Shore 64D; (2) the polymer comprises one or more of a thermoplastic elastomer, polylactic acid, polypropylene, nylon and polyethylene terephthalate; (3) the nucleating agent comprises at least one of calcium carbonate, talc, mica, montmorillonite, nano-silica, carbon black, and a carbon nanotube; (4) the chain extender comprises at least one of a bisoxazoline chain extender and an epoxy chain extender; (5) the antioxidant comprises at least one of an amine antioxidant and a phosphorus-containing antioxidant.

4. A preparation method of the polymer foamed fiber according to claim 2, comprising following steps: S1, premixing all components to obtain a mixture, subjecting the mixture to drying, melt extrusion and cooling to obtain a polymer fiber filament, and winding the polymer fiber filament to obtain a polymer fiber filament coil; S2, immersing the polymer fiber filament coil in a polyvinyl alcohol solution to form a barrier layer, then evenly sticking an inorganic filler to the barrier layer to form an isolation layer, so as to obtain a primary product of the polymer foamed fiber; S3, impregnating the primary product of the polymer foamed fiber in a supercritical fluid, conditionally inducing the primary product of the polymer foamed fiber to foam so as to obtain an induced polymer fiber; taking out the induced polymer fiber and subjecting the induced polymer fiber to pulling, rinsing, drying, and rewinding to obtain the polymer foamed fiber.

5. The preparation method according to claim 4, wherein the preparation method satisfies at least one of following items: (1) the drying in step S1 is hot air drying, and a moisture content of the mixture after drying is less than 0.05 wt. %; (2) the melt extrusion in step S1 is performed by using a twin-screw extruder, and temperatures from a feed port to an extrusion head of the twin-screw extruder are set to be 80 C., 180 C., 190 C., 205 C., 215 C., 180-190 C.; (3) a winding speed for winding the polymer fiber filament in step S1 is in a range of from 0.5 m/s to 2 m/s; (4) a diameter of the polymer fiber filament in step S1 is in a range of from 0.10 mm to 0.80 mm; (5) an interval of coating time between the barrier layer and the isolation layer in step S2 is in a range of from 10 s to 20 s.

6. The preparation method according to claim 4, wherein the polyvinyl alcohol solution in step S2 comprises following components in percentage by weight: 5-10 wt. % of polyvinyl alcohol (PVA), 70-80 wt. % of deionized water, 3-10 wt. % of hydrolyzed starch, and 3-10 wt. % of gypsum.

7. The preparation method according to claim 6, wherein a molecular weight of the polyvinyl alcohol is in a range of from 30,000 to 200,000, and an alcoholysis degree of the polyvinyl alcohol is 99%.

8. The preparation method according to claim 4, wherein the inorganic filler comprises at least one of talc powder, graphene, micro-nano calcium carbonate, and nano silicon dioxide; and a particle size of the inorganic filler is in a range of from 0.2 m to 10 m.

9. The preparation method according to claim 4, wherein the preparation method satisfies at least one of following items: (1) the supercritical fluid in step S3 comprises one of supercritical CO.sub.2, supercritical N.sub.2, and a mixed fluid of supercritical CO.sub.2 and supercritical N.sub.2; (2) a solubility of the supercritical fluid in the primary product of the polymer foamed fiber in step S3 is in a range of from 0.5 wt. % to 5.0 wt. %; (3) a hardness of the primary product of the polymer foamed fiber in step S3 is in a range of from Shore 80A to Shore 64D; (4) impregnating the primary product of the polymer foamed fiber in the supercritical fluid in step S3 is performed under a condition that a pressure is in a range of from 10 Mpa to 20 Mpa and a temperature is in a range of from 70 C. to 120 C.; (5) conditionally inducing the primary product of the polymer foamed fiber to foam is performed in a condition that the pressure and the temperature are rapidly changed, wherein a change rate for the pressure is in a range of from 10 Mpa/s to 15 Mpa/s and a change rate for the temperature is in a range of from 0 to 80 C./s; (6) rinsing the induced polymer fiber in step S3 is performed with water, and a flow rate of the water is in a range of from 0 to 1 m/s and a rinsing time is in a range of from 0 to 30 s.

10. A preparation method of the polymer foamed fiber according to claim 3, comprising following steps: S1, premixing all components to obtain a mixture, subjecting the mixture to drying, melt extrusion and cooling to obtain a polymer fiber filament, and winding the polymer fiber filament to obtain a polymer fiber filament coil; S2, immersing the polymer fiber filament coil in a polyvinyl alcohol solution to form a barrier layer, then adhering an inorganic filler to the barrier layer to form an isolation layer, so as to obtain a primary product of the polymer foamed fiber; S3, impregnating the primary product of the polymer foamed fiber in a supercritical fluid, conditionally inducing the primary product of the polymer foamed fiber to foam so as to obtain an induced polymer fiber; taking out the induced polymer fiber and subjecting the induced polymer fiber to pulling, rinsing, drying, and rewinding to obtain the polymer foamed fiber.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0041] FIG. 1 is a schematic diagram showing a cross-section of a polymer fiber filament coated with a barrier layer and an isolation layer in the preparation process of the present disclosure.

[0042] FIG. 2 is an optical image of a polymer foamed fiber prepared in Example 1 of the present disclosure.

[0043] FIG. 3 is a scanning electron microscopy (SEM) image showing a cross-section of the polymer foamed fiber prepared in Example 1 of the present disclosure.

[0044] FIG. 4 is a SEM image showing a cross-section of a polymer foamed fiber prepared in Example 5 of the present disclosure.

[0045] FIG. 5 is a SEM image showing a cross-section of a polymer foamed fiber prepared in Comparative Example 2 of the present disclosure.

DETAILED DESCRIPTION

[0046] With reference to examples of the present disclosure, technical solutions in the examples of the present disclosure are clearly and completely described below. Obviously, the examples described are only a part of examples of the present disclosure, not all of them. Based on the examples of the present disclosure, all other examples obtained by those skilled in the art, without creative work, are within the scope of protection of the present disclosure.

[0047] In the examples and comparative examples, experimental methods used are conventional methods, and materials and reagents, etc. used are commercially available, unless otherwise specified.

[0048] Materials used in the examples and comparative examples are as follows:

Polymer:

[0049] A1: thermoplastic polyurethane, melting point 200 C., hardness 98A, available from Lubrizol Specialty Chemical Company, USA; [0050] A2: thermoplastic polyurethane, melting point 190 C., hardness 85A, available from Jinjiang Guosheng Company, China; [0051] A3: thermoplastic polyester elastomer, melting point 220 C., hardness 55D, Type 5556, available from DuPont de Nemours, Inc., USA; [0052] A4: nylon elastomer, melting point 180 C., hardness 45D, Type 4510, Xubang New Materials Technology Co., Ltd., China; [0053] A5: polylactic acid, melting point 150 C., hardness 60D, Type 3001, available from NatureWorks LLC, USA; [0054] A6: thermoplastic polyester elastomer, melting point 240 C., hardness 72D, Type 7269, available from DuPont de Nemours, Inc., USA; [0055] Polyvinyl alcohol: available from Shanghai Aladdin Biochemical Technology Co., Ltd. China [0056] B1: Polyvinyl alcohol, Type 2699, molecular weight 114,000, alcoholysis degree 99%; [0057] B2: Polyvinyl alcohol, Type 1788, molecular weight 75,000, alcoholysis degree 99%; [0058] B3: Polyvinyl alcohol, Type 0588, molecular weight 22,000, alcoholysis degree 99%;

Inorganic Filler:

[0059] Talc powder: size 0.2-10 m, commercially available;

Nucleating Agent:

[0060] Calcium carbonate, average particle size 1 micron, commercially available; [0061] Talc, average particle size 1 micron, commercially available; [0062] Carbon black, average particle size 1 micron, commercially available;

Chain Extender:

[0063] Epoxy chain extender, effective component 99%, epoxy equivalent 285 g/mol, Type ADR4300, available from BASF Aktiengesellschaft, Germany;

Antioxidant:

[0064] Phenolic antioxidant, effective component 98%, available from BASF Aktiengesellschaft, Germany.

Preparation Method of Polyvinyl Alcohol Solution:

[0065] evenly mixing 10 wt. % of polyvinyl alcohol, 70 wt. % of deionized water, 10 wt. % of hydrolyzed starch, and 10 wt. % of gypsum to obtain the polyvinyl alcohol solution.

[0066] According to the above preparation method, polyvinyl alcohol B1, polyvinyl alcohol B2, and polyvinyl alcohol B3 are selected to prepare polyvinyl alcohol solution C1, polyvinyl alcohol solution C2, and polyvinyl alcohol solution C3, respectively.

Examples 1-9 and Comparative Examples 1-6

[0067] Components of the polymer foamed fibers, weight parts of the components and condition parameters in Examples 1-9 and Comparative Examples 1-6 were shown in Table 1, and performance parameters of the prepared polymer foamed fibers were shown in Table 2. A diameter of a polymer foamed fiber is measured by using an optical fiber diameter analyzer, according to Chinese National Standard GB/T20732-2006. A skin layer thicknesses and a pore size of a polymer foamed fiber are respectively determined, by measuring the skin layer thickness and the pore size (diameter) of the polymer foamed fiber in multiple images obtained by a scanning electron microscope (SEM) or by a microscope, repeating the measurement for several times, and averaging the results. Density of a polymer foamed fiber is measured according to Chinese National Standard GB/T14335.

[0068] Preparation method of the polymer foamed fiber in each of Examples 1-9 and Comparative Examples 1-6 comprises the following steps: [0069] S1, premixing and drying all components to obtain a mixture, placing the mixture into a twin-screw extruder and subjecting the mixture to melt extrusion and cooling to obtain a polymer fiber filament, and winding the polymer fiber filament to obtain a polymer fiber filament coil; wherein the drying is hot air drying, and a moisture content of the mixture after drying is less than 0.05 wt. %, temperatures from a feed port to an extrusion head of the twin-screw extruder are set to be 80 C., 180 C., 190 C., 205 C., 215 C., and 180-190 C., a winding speed for winding the polymer fiber filament is in a range of from 0.5 m/s to 2 m/s, and a diameter of the polymer fiber filament is in a range of from 0.10 mm to 0.80 mm; [0070] S2, loading the polymer fiber filament coil into a self-made coating device, pulling the polymer fiber filament by a transmission device through the self-made coating device and re-winding the polymer fiber filament at the other end of the self-made coating device; during the pulling and rewinding process, immersing the polymer fiber filament in a polyvinyl alcohol solution to form a barrier layer, and then evenly sticking an inorganic filler to the barrier layer before the barrier layer is completely air-dried to form an isolation layer so as to obtain a primary product of the polymer foamed fiber; wherein an interval of coating time between the barrier layer and the isolation layer is in a range of from 10 s to 20 s, and the inorganic filler is talc powder (the inorganic filler also may be graphene, micro-nano calcium carbonate, or nano silicon dioxide); at this moment, the primary product of the polymer foamed fiber had a cross-section as shown in FIG. 1, where a polymer fiber filament was coated with a barrier layer and an isolation layer; [0071] S3, placing the primary product of the polymer foamed fiber in a high-pressure device and impregnating the primary product of the polymer foamed fiber in a supercritical fluid to achieve an equilibrium state, wherein in the high-pressure device, a pressure is in a range of from 10 MPa to 20 Mpa, and a temperature in a range of from 70 C. to 120 C.; rapidly changing the pressure and the temperature in the high-pressure device to destroy the equilibrium state and conditionally inducing the primary product of the polymer foamed fiber to foam so as to obtain an induced polymer fiber; wherein a change rate for the pressure is in a range of from 10 to 15 Mpa/s and a change rate for the temperature is in a range of from 0 to 80 C./s; then taking out the induced polymer fiber and subjecting the induced polymer fiber to pulling, rinsing, drying, and rewinding to obtain the polymer foamed fiber, wherein a hardness of the primary product of the polymer foamed fiber is in a range of from Shore 80A to Shore 64D; the supercritical fluid is supercritical CO.sub.2; a solubility of the supercritical fluid in the primary product of the polymer foamed fiber is in a range of from 0.5 wt. % to 5.0 wt. %; a flow rate of water for rinsing is in a range of from 0 to 1 m/s and a rinsing time is in a range of from 0 to 30 s.

TABLE-US-00001 TABLE 1 Components and quantities thereof in the examples (E) and comparative examples (CE) (parts by weight). Component E1 E2 E3 E4 E5 E6 E7 E8 E9 CE 1 CE 2 CE 3 CE 4 CE 5 CE 6 Polymer A1 95 97 90 100 / / / / 95 / 95 95 95 95 95 A2 / / / / 95 / / / / / / / / / / A3 / / / / / 95 / / / / / / / / / A4 / / / / / / 95 / / / / / / / / A5 / / / / / / 95 / / / / / / / A6 / / / / / / / / / 95 / / / / / Nucleating Talc 3 5 / / 3 3 3 3 3 3 3 3 3 3 / agent Calcium / / 10 / / / / / / / / / / / / carbonate Carbon / / / 1 / / / / / / / / / / / black Chain extender / / / 0.2 / / / / / / / / / / Antioxidant 0.2 0.3 0.5 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Extrusion condition of Moisture content: 0.02 wt. %, Temperature of extruder: 100 C., filament 160 C., 185 C., 200 C., 210 C., 180-190 C. Diameter of filament 0.2 0.2 0.4 0.1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 after extrusion, mm Polyvinyl alcohol C1 C1 C1 C1 C1 C1 C1 C1 C2 C1 C3 C1 C1 C1 C1 solution Thickness of barrier 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 layer, mm Thickness of isolation 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 0.03 layer, mm Solubility of 3.0 1.0 5.0 0.5 3.0 3.0 3.0 3.0 3.0 3.0 3.0 0.1 3.0 3.0 3.0 supercritical CO.sub.2, % Impregnation 80 100 120 70 80 80 80 80 80 80 80 80 80 80 80 temperature, C. Impregnation pressure, 15 18 20 10 15 15 15 15 15 15 15 15 15 15 15 Mpa Hardness of primary 95 A 95 A 95 A 95 A 82 A 52 D 42 D 57 D 95 A 95 A 95 A 95 A 95 A 95 A 95 A product of polymer foamed fiber Change rate for 15 10 10 10 15 15 15 15 15 15 15 15 1 0 15 pressure, Mpa/s Change rate for 0 0 80 0 0 0 0 0 0 0 0 0 0 100 0 temperature, C./s

TABLE-US-00002 TABLE 2 Performance parameters of polymer foamed fibers Diameter of Skin layer Density of polymer thickness of polymer Pore foamed fiber, polymer foamed foamed fiber, size, Item mm fiber, mm g/cm.sup.3 m Foaming effect Example 1 0.3 0.01 0.4 10~20 High-density and uniform pores, relatively good foaming effect Example 2 0.3 0.05 0.45 10~20 High-density and uniform pores, relatively good foaming effect Example 3 0.7 0.1 0.5 30~50 High-density and uniform pores, relatively good foaming effect Example 4 0.2 0.01 0.45 1~10 High-density and uniform pores, relatively good foaming effect Example 5 0.35 0 0.3 20~30 High-density and uniform pores, good foaming effect Example 6 0.4 0.1 0.5 10~30 High-density and relatively uniform pores, relatively good foaming effect Example 7 0.5 0.1 0.4 20~40 High-density and relatively uniform pores, relatively good foaming effect Example 8 0.5 0.1 0.6 20~40 High-density and relatively uniform pores, relatively good foaming effect Example 9 0.5 0.1 0.7 1~20 High-density and relatively uniform pores, relatively good foaming effect Comparative 0.2 0.2 1.2 0 No pore, no foaming Example 1 Comparative 0.25 0.2 1.1 1~5 Sparse pores, uneven Example 2 distribution of pores, poor foaming effect Comparative 0.25 0.2 1.0 1~10 Sparse pores, uneven Example 3 distribution of pores, poor foaming effect Comparative 0.2 0.2 1.2 0 No pore, no foaming Example 4 Comparative 0.3 0.2 0.9 1~10 Sparse pores, uneven Example 5 distribution of pores, poor foaming effect Comparative 0.3 0.15 0.8 1~10 Sparse pores, uneven Example 6 distribution of pores, poor foaming effect

[0072] FIG. 2 was an optical image of a polymer foamed fiber prepared in Example 1 of the present disclosure. FIG. 3 was a scanning electron microscopy (SEM) image showing a cross-section of the polymer foamed fiber prepared in Example 1 of the present disclosure.

[0073] FIG. 4 was a SEM image showing a cross-section of a polymer foamed fiber prepared in Example 5 of the present disclosure. FIG. 5 was a SEM image showing a cross-section of a polymer foamed fiber prepared in Comparative Example 2 of the present disclosure.

[0074] As can be seen from the data in Table 2, the polymer foamed fibers obtained in the examples of the present disclosure all have porous structures, suitable pore sizes, uniform pores, uniform fiber thickness, controllable skin layer thickness and low density.

[0075] In Comparative Example 1, the hardness of the polymer selected is not suitable, so the prepared polymer foamed fiber has a high density and cannot be foamed to form pores. In Comparative Example 2, the molecular weight of polyvinyl alcohol in the polyvinyl alcohol solution is not suitable, resulting in a reduced foaming effect, sparse pores, uneven distribution of pores and poor foaming effect. In Comparative Example 3, the solubility of supercritical CO.sub.2 in the primary product of the polymer foamed fiber is not suitable, resulting in a reduced foaming effect. Neither the change rate of pressure in Comparative Example nor the change rate of temperature in Comparative Example 5 is suitable, so the obtained polymer foamed fibers both have high skin layer thickness and high density. Further, the polymer foamed fiber prepared in Comparative Example 4 cannot be foamed to form pores and the polymer foamed fiber prepared in Comparative Example 5 has sparse pores, which are unevenly distributed. In Comparative Example 6, no nucleating agent is added, so the polymer foamed fiber prepared has sparse pores, which are unevenly distributed, and the foaming effect is poor.

[0076] As can be seen from FIGS. 3 and 4, the polymer foamed fiber prepared in Example 5 of the present disclosure does not have a cortex. Compared with Example 1, the polymer foamed fiber prepared in Example 5 of the present disclosure has larger and more uniform pores and more uniform pore distribution.

[0077] The above examples are only intended to illustrate the principles and effects of the present disclosure, rather than to limit the present disclosure. Any one skilled in the art can modify or change the above examples, without violating the spirit and scope of the present disclosure. Therefore, all equivalent modifications or changes made by those skilled in the art, without departing from the spirit and technical ideas disclosed by the present disclosure, should still be covered by claims of the present disclosure.