Preparation method of bio-based polymer melt-spun fiber with high mechanical property

Abstract

The invention discloses a preparation method of bio-based polymer melt-spun fibers with high mechanical properties. The method comprises the following steps: drying bio-based polymer slices in a vacuum oven, carrying out melt extrusion through a twin-screw extruder, carrying out fiber drafting by using a traction winding machine with an adjustable rotating speed, and finally collecting the fibers through a fiber winding machine. The method solves the key problems of insufficient strength, poor continuity, uneven thickness, poor toughness and the like of the traditional bio-based polymer in melt spinning. The spinning method is simple to operate and can be used for large-scale production of fibers, and the prepared bio-based polymer melt-spun fibers are fully drafted, are good in continuity, uniform in thickness and high in impact resistance, have better toughness, can be widely applied to the field of textiles for clothing, decoration and industry of automobiles, ordnance, cables, electronic appliances and the like, and have wide application prospects. The method has a remarkable industrial application value.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of bio-based polyamide melt spinning materials, and specifically relates to a method for preparing bio-based polymer melt spinning fibers with high mechanical properties. Background Art

[0002] In recent years, synthetic polymers have replaced many traditional materials and are used in various fields of daily life. However, with the use of a large number of petroleum-based polymers, people are paying more and more attention to environmental issues and are looking for renewable resources to replace limited raw materials such as petroleum. The demand for bio-based polymers is increasing. The application of bio-based polymers can reduce pollution to the environment, achieve energy conservation and resource saving, and is in line with the current concept of green and sustainable development.

[0003] Bio-based polymers refer to polymer materials prepared from renewable biomass through biosynthesis, chemical synthesis and other methods. They include the following categories: (1) Polylactic acid (PLA): Polylactic acid is a bio-based plastic made from the polymerization of lactic acid. It has good biodegradability and biocompatibility and is widely used in packaging materials, disposable tableware and other fields. (2) Polyhydroxyalkanoate (PHA): PHA is a natural polymer material produced by microbial fermentation. It has excellent biodegradability and biocompatibility and can be used in medical and packaging fields. (3) Polyglycolic acid (PGA): PGA is a polymer with good biodegradability and can be used for drug sustained release and tissue engineering scaffolds. (4) Polybutylene succinate (PBS): PBS is an aliphatic polyester with good biodegradability and is commonly used in packaging and agricultural fields. (5) Polybutylene terephthalate-adipate (PBAT): PBAT is a polymer prepared by the polymerization of terephthalic acid, adipic acid and 1,4-butanediol. It has good biodegradability. (6) Bio-based polyamide (PA): Bio-based polyamide is a type of polymer produced by polymerization of bio-based monomers and has good mechanical properties and thermal stability.

[0004] The preparation methods of bio-based polymer fibers mainly include: melt spinning, wet spinning, electrospinning, spunbonding, etc. Compared with other methods, the advantages of melt spinning technology are high spinning production efficiency, simple process flow, no need for solvents and residual solvent recovery, low cost, wide applicability, environmental friendliness, and controllable fiber properties.

[0005] Nylon 11 is a commercial aliphatic polyamide extracted from castor oil, which accounts for only a small part of the polyamide production. Nylon 11 is a long carbon chain flexible polymer with excellent impact resistance, good dimensional stability, excellent electrical insulation, stable chemical properties, low water absorption, good oil resistance, low temperature resistance, easy processing, and due to its biocompatibility and lower hydrophilicity compared to the more widely used polyamide 6 and 6.6, nylon 11 is used in a wide range of fields, such as: automobiles, ordnance, cables, electronic appliances, etc.

[0006] CN115536853A discloses a method for preparing PA11 elastomer from 11-aminoundecanoic acid. Under normal pressure, a flux is added to a reactor and heated to 180-210°C under stirring; then 11-aminoundecanoic acid, a first catalyst and a capping agent are added, stirring is continued to melt the mixture and the temperature is raised to 200-230°C for pre-polycondensation reaction, and the flux is evaporated and collected at the same time; then the soft segment structural unit, the second catalyst and the chain extender are added in sequence, and the reaction is vacuumed to an absolute pressure of 0.03-0.05MPa; after the vacuuming reaction is completed, the vacuuming is stopped, and excess water is evaporated under N-2 conditions to obtain the PA11 elastomer. The PA11 elastomer is synthesized by using polybutadiene diol with good hydrolysis stability as the soft segment and anhydride as the chain extender, making full use of the water generated by polymerization, and optimizing the addition sequence of the flux and 11-aminoundecanoic acid.

[0007] CN119101333A discloses a bio-based high-strength and high-toughness polylactic acid (PLA) / polyamide 11 alloy material and its preparation method in the field of polymer materials. The raw materials include 60-80% by weight of poly-L-lactic acid, 13-37% of polyamide 11 and 3-7% of reactive compatibilizer; the reactive compatibilizer is obtained by reacting amino-terminated polyamide 11 and hydroxyl-terminated poly-D-lactic acid with epoxy chain extender. The addition of reactive compatibilizer can effectively reduce the size of polyamide 11 phase, and polylactic acid undergoes heterogeneous nucleation on polyamide 11 crystals, and the spherulite size of polylactic acid is significantly reduced, so that the polylactic acid / polyamide 11 alloy material exhibits excellent ductility and crystallization ability. However, the nylon 11 fibers obtained by the existing methods often have the problem of poor uniformity, and the mechanical properties need to be improved.

[0008] Melt spinning is a common fiber production process that has been widely studied. The spinning process, such as the stretching ratio and the stretching temperature, has a great influence on the crystal structure and final performance of the fiber. The present invention uses a melt spinning method to prepare a bio-based polymer fiber (especially bio-based polyamide 11) with excellent uniformity and mechanical properties, and has the characteristics of high production efficiency and low production cost, and can be mass-produced. Summary of the invention

[0009] The purpose of the present invention is to provide a method for preparing bio-based polymer melt-spun fibers with high mechanical properties, so as to solve the problems of insufficient strength of currently prepared bio-based polymer melt-spun fibers, and limitations of fiber continuity and uniformity during the spinning process. The obtained polyamide 11 is compared with other types of polyamides to enrich the types of bio-based polyamide fibers. The bio-based polymer fibers prepared by the method, such as bio-based polyamide 11 fibers and PLA fibers, not only have excellent uniformity, but also have strong impact resistance and better toughness, providing direction and application prospects for subsequent research.

[0010] The present invention adopts the following technical solutions:

[0011] A method for preparing bio-based polymer melt-spun fibers with high mechanical properties is prepared by using a twin-screw extruder and a continuous drawing and winding process, comprising melt-extruding dried bio-based polymer slices through a twin-screw extruder, drawing the fibers using a traction winder with adjustable speed, and finally collecting the fibers through a fiber winder; the preparation method specifically comprises:

[0012] (1) Before melt spinning, a certain amount of bio-based polymer chips are dried in a vacuum drying oven at 70°C-80°C for 12h-16h to prevent moisture from affecting the structural properties of the final fiber during the melt spinning process.

[0013] (2) Feeding the dried bio-based polymer chips into a twin-screw extruder for spinning at a spinning temperature of 200-220° C. The extrusion speed is 60-1000 mm / min.

[0014] (3) The bio-based polymer nascent fibers need to be drawn by a continuous and precisely controllable traction winder. In the order of contact with the fibers, the speed of the first guide roller GR1 is 190-300 rpm, the speed of the second guide roller GR2 is 190-300 rpm, and the speed of the fiber winder is no more than 300 rpm.

[0015] The present invention adopts melt spinning to prepare bio-based polymer fibers. The key parameters in the spinning process need to be precisely controlled to ensure the successful acquisition of uniform, stable, continuous fibers with excellent mechanical properties. For example, the bio-based polymer chips should usually be dried in advance to control the moisture content, the melt extrusion temperature should not be too low or too high, and the extrusion speed and the rotation speed of the traction winder and the subsequent fiber winder should be precisely controlled, which has an important influence on the crystal structure and final performance of the obtained fiber. The most preferred process parameters are a melt extrusion temperature of 200-220°C, an extrusion speed of 60mm / min, a traction winder rotation speed controlled at 190-300rpm, and a fiber winder rotation speed controlled at 100-300rpm.

[0016] The beneficial effects of the present invention are:

[0017] The present invention obtains a bio-based polymer melt-spun fiber with high mechanical properties. The obtained bio-based polymer, nylon 11 fiber or PLA fiber has excellent uniformity and mechanical properties, and has excellent impact resistance, good dimensional stability, excellent electrical insulation, stable chemical properties, low water absorption, good oil resistance, low temperature resistance, and easy processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the production process of PA11.

[0019] Figure 2 It is the PA11 filament fiber of Example 2.

[0020] Figure 3 It is the PA11 filament fiber of Example 3.

[0021] Figure 4 It is the PA11 filament fiber of Example 4.

[0022] Figure 5 It is the PA11 filament fiber of Example 5.

[0023] Figure 6 It is the PA11 filament fiber of Example 6.

[0024] Figure 7 It is the PA11 filament fiber of Example 7.

[0025] Figure 8 These are light microscope images of PA11 fibers at different magnifications.

[0026] Fig. 9 This is the mechanical properties diagram of PA11 fiber. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below with reference to the accompanying drawings and specific examples.

[0028] Example 1

[0029] like Figure 1 The figure shows the production process of PA11. The preparation method of bio-based PA11 includes the following steps: drying PA11 slices in a vacuum oven at 70°C for 12 hours. Melt extrusion is performed through a twin screw, the extrusion temperature is 190-200°C, and the melt extrusion speed is 60rpm; continuous drawing and winding equipment is used for drawing, the speed of the first guide roller GR1 is 60rpm, the speed of the second guide roller GR2 is 50rpm, and the speed of the fiber winder is 300rpm. If the temperature is too low, the material will not be fully melted and extrusion will be difficult.

[0030] Example 2

[0031] like Figure 1-2 The figure shows the production process diagram of PA11. The preparation method of bio-based PA11 includes the following steps: drying PA11 slices in a vacuum oven at 70°C for 12 hours. Melt extrusion is performed by a twin screw, the extrusion temperature is 200-220°C, and the melt extrusion speed is 60rpm; continuous drawing and winding equipment is used for drawing, the speed of the first guide roller GR1 is 60rpm, the speed of the second guide roller GR2 is 50rpm, and the speed of the fiber winder is 100rpm. At low drawing multiples, the fiber is not fully stretched, the orientation is insufficient, the diameter is relatively thick, and the diameter is >200μm, which does not meet the regulations.

[0032] Example 3

[0033] like Figure 1 , 3 The figure shows the production process diagram of PA11. The preparation method of bio-based PA11 includes the following steps: drying PA11 slices in a vacuum oven at 70°C for 12 hours. Melt extrusion is performed by a twin screw, the extrusion temperature is 200-220°C, and the melt extrusion speed is 60rpm; continuous drawing and winding equipment is used for drawing, the first guide roller winding speed GR1 is 180rpm, the second guide roller speed GR2 is 150rpm, and the fiber winder speed is 200rpm. The fiber is gradually stretched, and the fiber becomes thinner directly, but the mechanical properties are poor and it is easy to break.

[0034] Example 4

[0035] like Figure 1 , 4 9 is a production process diagram of PA11. The preparation method of bio-based PA11 includes the following steps: drying PA11 slices in a vacuum oven at 70°C for 12 hours. Melt extrusion is performed through a twin screw, the extrusion temperature is 200-220°C, and the melt extrusion speed is 60rpm; continuous drawing and winding equipment is used for drawing, the first guide roller winding speed GR1 is 240rpm, the second guide roller speed GR2 is 200rpm, and the fiber winder speed is 300rpm. Figure 8 As shown, the fiber diameter becomes thinner and the thickness is uniform, with a diameter of 150-160 μm and good mechanical properties, a breaking strength of 2.14 N and a breaking elongation of 826.15%.

[0036] Example 5

[0037] like Figure 1 , 5The figure shows the production process diagram of PA11. The preparation method of bio-based PA11 includes the following steps: drying PA11 slices in a vacuum oven at 70°C for 12 hours. Melt extrusion is performed by a twin screw, the extrusion temperature is 200-220°C, the extrusion speed is 10mm / min, the speed GR1 of the first guide roller is 20rpm, the speed GR2 of the second guide roller is 15rpm, and the speed of the fiber winder is 100rpm. The nylon 11 fiber obtained under this condition has a thin diameter and is easy to break. In addition, the spinning viscose extruded by the screw extruder is uneven, and the subsequent drawing is not sufficient, the thickness is uneven, and there are obvious thick sections and details.

[0038] Example 6:

[0039] like Figure 1 , 6 The figure shows the production process diagram of PA11. The preparation method of bio-based PA11 includes the following steps: drying PA11 slices in a vacuum oven at 70°C for 12 hours. Melt extrusion is performed by a twin screw, the extrusion temperature is 200-220°C, the extrusion speed is 20mm / min, the speed GR1 of the first guide roller is 40rpm, the speed GR2 of the second guide roller is 20rpm, and the speed of the fiber winder is 100rpm. The nylon 11 fiber obtained under this condition has a fine diameter of 70-120μm. The spinning viscose extruded by the screw extruder is uneven, and is not fully stretched afterwards, so the thickness is uneven, with obvious thick sections and details.

[0040] Example 7:

[0041] like Figure 1 , 7 The figure shows the production process diagram of PA11. The preparation method of bio-based PA11 includes the following steps: drying PA11 slices in a vacuum oven at 70°C for 12 hours. Melt extrusion is performed by a twin screw, the extrusion temperature is 200-220°C, the extrusion speed is 30mm / min, the speed GR1 of the first guide roller is 60rpm, the speed GR2 of the second guide roller is 40rpm, and the speed of the fiber winder is 100rpm. The nylon 11 fiber obtained under this condition has a fine diameter of 70-120μm. The spinning viscose extruded by the screw extruder is uneven, and is not fully stretched afterwards, so the thickness is uneven, with obvious thick sections and details.

[0042] Example 8

[0043] The method for preparing melt-spun fibers of bio-based polymer PLA comprises the following steps: drying PLA slices in a vacuum oven at 80°C for 16 hours. Melt extrusion is performed by a twin screw at an extrusion temperature of 200-220°C and a melt extrusion speed of 70rpm; continuous drawing and winding equipment is used for drawing at a winding speed of 200rpm (the speeds of the first guide wire roller and the second guide wire roller are the same), and the speed of the fiber winder is 100rpm. The fiber has a uniform diameter of 150-160μm, good mechanical properties, a breaking strength of 2.2N, and a breaking elongation of 44.5%.

[0044] The embodiments described above provide a detailed description of the preparation scheme of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the present invention. Any modifications, supplements or similar substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing bio-based polymer melt-spun fibers with high mechanical properties, characterized in that: The method is prepared by using a twin-screw extruder and a continuous drawing and winding process, which includes melt-extruding dried bio-based polymer chips through a twin-screw extruder, drawing the fibers using a traction winder with adjustable speed, and finally collecting the fibers through a fiber winder.

2. The method for preparing a bio-based polymer melt-spun fiber with high mechanical properties according to claim 1, characterized in that: Before melt spinning, the bio-based polymer chips are dried in a vacuum drying oven at 70-80° C. for 12-16 hours to obtain completely dried bio-based polymer chips to prevent moisture from affecting the morphology and structure of the final fibers during the melt spinning process.

3. The method for preparing a bio-based polymer melt-spun fiber with high mechanical properties according to claim 1, characterized in that: The spinning temperature during the melt extrusion is 200-220°C.

4. The method for preparing a bio-based polymer melt-spun fiber with high mechanical properties according to claim 1, characterized in that: The extrusion speed is 60-1000 mm / min.

5. The method for preparing a bio-based polymer melt-spun fiber with high mechanical properties according to claim 1, characterized in that: The rotation speed of the traction winder is precisely controlled, and the speed GR1 of the first godet roller that first contacts the fiber is controlled to be 190-300 rpm, and the speed GR2 of the second godet roller that contacts the fiber later is controlled to be 190-300 rpm.

6. The method for preparing a bio-based polymer melt-spun fiber with high mechanical properties according to claim 1, characterized in that: The fiber winder has a rotation speed which is precisely controlled to not exceed 300 rpm.

7. A bio-based polymer melt-spun fiber with high mechanical properties, characterized in that: Prepared by the method according to any one of claims 1 to 6.

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