Polylactic acid yarn, preparation method thereof and polylactic acid fabric

Abstract

The invention provides a polylactic acid yarn, a preparation method thereof and a polylactic acid fabric. The preparation method of the polylactic acid yarn comprises the following steps: S1, dissolving polylactic acid powder in a solvent system containing dimethyl carbonate, and stirring to obtain a polylactic acid spinning solution; s2, the polylactic acid spinning solution is subjected to conjugate electrostatic spinning, and the polylactic acid yarn is obtained. Compared with the prior art, the prepared polylactic acid yarn overcomes the defects of chloroform, acetone, dichloromethane, trichloromethane, methylbenzene and other toxic solvents commonly used in a PLA solution spinning method, the environment-friendly green solvent DMC is combined, micro-nano PLA fibers are introduced into preparation of the PLA yarn and fabric of the PLA yarn, the polylactic acid yarn has the biodegradability and biocompatibility of polylactic acid, and the PLA yarn has the advantages of being capable of being used for preparing the micro-nano PLA fibers and the fabric of the PLA yarn. The specific surface area and the porosity are enhanced, and the application scenarios of the PLA are increased.

Description

Technical Field

[0001] The invention relates to the technical field of micro-nano-sized polylactic acid yarns, in particular to a polylactic acid yarn and a preparation method thereof, and a polylactic acid fabric. Background Art

[0002] Polylactic acid (PLA) fiber, as a bio-based material originating from and returning to nature, is gradually showing its unique charm in the textile and medical fields. It originates from corn starch, a renewable resource, and is transformed into PLA polymer through a series of green transformation processes. Finally, through melt spinning or solution spinning processes, fiber products of various forms are prepared, including PLA yarn, which not only has excellent biocompatibility and degradability, but also has excellent antibacterial properties and processing adaptability, making it an ideal choice for medical and fashion textile products.

[0003] Melt-spun PLA yarns require very high temperatures and harsh processing conditions, while the solvents used in solution-spun PLA yarns, such as chloroform, acetone, dichloromethane, chloroform, and toluene, are toxic and not environmentally friendly, and the process is complicated. In addition, both melt-spun PLA yarns and solution-spun PLA yarns are micrometer-scale. Electrospun micro-nano fibers are often used in scale structure design due to their unique scale effect and easy processing and molding properties, with enhanced specific surface area and porosity. However, the solutions currently used in electrospun PLA fibers are the same as the solvents used in solution spinning, which do not meet the green transformation and sustainable development needs of the textile industry. Therefore, for the preparation of PLA yarns at the micro-nano scale, green solvents are urgently needed to replace them, and then they are woven into corresponding PLA fabrics to increase the application scenarios of PLA. Summary of the invention

[0004] 1. Technical issues to be solved

[0005] In view of the deficiencies in the prior art, the present invention provides a polylactic acid yarn and a preparation method thereof, and a polylactic acid fabric, which solve the problems raised in the above-mentioned background technology.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0008] According to a first aspect of the present invention, there is provided a method for preparing polylactic acid yarn, comprising the following steps:

[0009] S1, dissolving polylactic acid powder in a solvent system containing dimethyl carbonate, stirring, and obtaining a polylactic acid spinning solution;

[0010] S2. The polylactic acid spinning solution is subjected to conjugated electrospinning to obtain polylactic acid yarn.

[0011] Preferably, in step S1, the solvent system further contains dimethylformamide or dimethylacetamide;

[0012] The volume ratio of dimethyl carbonate to dimethylformamide or dimethylacetamide in the solvent system is 1:0.1-1.

[0013] Preferably, in step S1, the mass fraction of polylactic acid in the polylactic acid spinning solution is 9-30wt%.

[0014] Preferably, in step S1, the stirring temperature is 25-100° C., and the stirring time is 0.5-10 h.

[0015] Preferably, in step S2, the conjugate electrospinning condition parameters are:

[0016] The flow rate of the spinneret is 0.01-10 mL / h, the positive and negative pressures are 3-40 kV respectively, the rotation speed of the collecting roller is 10-1000 r / min, the spinning distance is 5-50 cm, the spinning temperature is 0-35° C., and the relative humidity is 60-70%.

[0017] Preferably, in step S2, the polylactic acid spinning solution can also be subjected to conjugate electrospinning on the micron PLA core yarn, and the moving speed of the micron PLA core yarn is 0.1 to 20 mm / s.

[0018] According to a second aspect of the present invention, a polylactic acid yarn is provided, wherein the diameter of the polylactic acid yarn is 10 to 1000 nm.

[0019] Preferably, the polylactic acid yarn comprises a micron PLA core yarn and a micro-nano PLA skin layer coated on the micron PLA core yarn, the diameter of the micron PLA core yarn is 5 to 15 μm, and the diameter of the micro-nano PLA skin layer is 10 to 1000 nm.

[0020] According to a third aspect of the present invention, a polylactic acid fabric is provided, wherein polylactic acid yarns are woven to obtain the polylactic acid fabric.

[0021] (III) Beneficial effects

[0022] The present invention provides a polylactic acid yarn and a preparation method thereof, and a polylactic acid fabric, which have the following beneficial effects:

[0023] (1) The present invention provides a method for preparing polylactic acid yarn, which uses a green organic solvent to achieve efficient dissolution of PLA polymer. Compared with traditional organic solvents such as chloroform, acetone, dichloromethane, chloroform, and toluene, the selected green solvent system contains dimethyl carbonate, which can dissolve polylactic acid powder while reducing pollution to the environment.

[0024] (2) This scheme provides a method for preparing a polylactic acid yarn, which uses a conjugated electrospinning method to immerse micro-nano PLA fibers into PLA yarns and fabrics to increase the specific surface area and porosity. Compared with traditional polylactic acid yarns, it has more application scenarios and can be used in filter materials, medical dressings, biosensors and other fields.

[0025] (3) This scheme provides a method for preparing polylactic acid yarn. In addition to pure PLA yarn, PLA micro-nano fibers can also be coated on PLA core yarn. The micro-nano size of the cortex and the micron size of the core yarn form a scale span, which not only has biodegradability and biocompatibility, but also further increases the specific surface area and porosity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the conjugate electrospinning principle of the core-skin structure polylactic acid yarn prepared in Example 1 of the present invention;

[0027] Figure 2 This is a scanning electron microscope image of the core-skin structure polylactic acid yarn prepared in Example 1 of the present invention, wherein (a) is a micron polylactic acid core yarn, and (b) is a polylactic acid yarn coated with micro-nano polylactic acid fibers;

[0028] Figure 3 This is a scanning electron microscope image of the surface micro-nano fibers of the polylactic acid yarn with a core-skin structure prepared in Example 2 of the present invention;

[0029] Figure 4 The scanning electron microscope images of the core-sheath structure polylactic acid yarn prepared at different collecting drum rotation speeds of the present invention are as follows: (a) 100 r / min, (b) 200 r / min, (c) 300 r / min, and (d) 400 r / min. DETAILED DESCRIPTION

[0030] In order to better illustrate the content of the present invention, a detailed description is given below in conjunction with specific embodiments.

[0031] Example 1

[0032] A method for preparing polylactic acid yarn is based on green solvent, and the specific steps are:

[0033] (1) At room temperature, 7 L of dimethyl carbonate and 3 L of dimethylacetamide were mixed, and polylactic acid powder was added, and the mixture was stirred in a water bath at 70° C. and a speed of 200 r / min for 2 h to obtain a polylactic acid spinning solution with a mass fraction of 15 wt%;

[0034] (2) The prepared polylactic acid spinning solution was injected into two spinnerets for conjugated electrospinning, and the melt-spun polylactic acid micron yarn was used as the core yarn. The spinneret was set to push out the spinning solution at a stable flow rate of 1 mL / h, and the positive and negative pressures were both 7 kV, so that the spinning solution formed a stable triangular cone, such as Figure 1 As shown, at the same time, the rotation speed of the drum is adjusted to 100r / min, the moving speed of the core yarn is 1mm / s, and the receiving distance is 15cm, so that the polylactic acid micro-nano fibers can be uniformly and orderly deposited on the polylactic acid core yarn to form a polylactic acid micro-nano skin layer, the spinning temperature is within 25±3℃, and the relative humidity is 65±5% to ensure the stability of the spinning process and the quality of the polylactic acid micro-nano fibers;

[0035] (3) The prepared polylactic acid yarn is subjected to a plain weave on a rapier loom to obtain a polylactic acid fabric, wherein the polylactic acid micro-nano fibers of the polylactic acid yarn are coated on the polylactic acid micron core yarn, such as Figure 2 As shown in Figure (a), the diameter of the polylactic acid micron core yarn is 10.41 μm. Figure 2 As shown in Figure (b), the diameter of the polylactic acid micro-nano cortical fiber of the polylactic acid yarn is 960nm. The micron size of the core yarn and the micro-nano size of the cortex have a scale span, forming a multi-scale polylactic acid yarn.

[0036] Example 2

[0037] A method for preparing polylactic acid yarn is based on green solvent, and the specific steps are:

[0038] (1) At room temperature, 8 L of dimethyl carbonate and 2 L of dimethylacetamide were mixed, and polylactic acid powder was added, and then stirred in a water bath at 70° C. and 200 r / min for 2 h to obtain a polylactic acid spinning solution with a mass fraction of 14 wt%;

[0039] (2) The prepared polylactic acid spinning solution is injected into two spinnerets of conjugated electrospinning, and the melt-spun polylactic acid micron yarn is used as the core yarn. The spinneret is set to push out the spinning solution at a stable flow rate of 1 mL / h, and the positive and negative pressures are both 7 kV, so that the spinning solution forms a stable triangular cone. At the same time, the rotation speed of the drum is adjusted to 100 r / min, the moving speed of the core yarn is 1 mm / s, and the receiving distance is 15 cm, so that the polylactic acid micro-nano fibers can be uniformly and orderly deposited on the polylactic acid core yarn to form a polylactic acid micro-nano cortex. The spinning temperature is within 25±3°C and the relative humidity is 65±5% to ensure the stability of the spinning process and the quality of the polylactic acid micro-nano fibers. The prepared polylactic acid yarn polylactic acid micro-nano fibers are coated on the polylactic acid micron core yarn to form a multi-scale polylactic acid yarn, wherein the polylactic acid micro-nano fibers located in the cortex are as follows Figure 3 As shown, the surface is smooth and straight;

[0040] (3) The obtained polylactic acid yarn is subjected to rib weave on a circular knitting machine to obtain a polylactic acid fabric.

[0041] Example 3

[0042] A method for preparing polylactic acid yarn is based on green solvent, and the specific steps are:

[0043] (1) At room temperature, 8 L of dimethyl carbonate and 2 L of dimethylacetamide were mixed, and polylactic acid powder was added, and then stirred in a water bath at 70° C. and 200 r / min for 2 h to obtain a polylactic acid spinning solution with a mass fraction of 15 wt%;

[0044] (2) Injecting the prepared polylactic acid spinning solution into two spinnerets of conjugated electrospinning, using melt-spun polylactic acid micron yarn as the core yarn, setting the spinneret to push out the spinning solution at a stable flow rate of 1 mL / h, applying positive and negative pressures of 7 kV, so that the spinning solution forms a stable triangular cone, and at the same time, adjusting the speed of the drum to 100 r / min, the moving speed of the core yarn to 1 mm / s, and the receiving distance to 15 cm, so that the polylactic acid micro-nano fibers can be uniformly and orderly deposited on the polylactic acid core yarn to form a polylactic acid micro-nano cortex. The spinning temperature is within 25±3°C and the relative humidity is 65±5% to ensure the stability of the spinning process and the quality of the polylactic acid micro-nano fibers. The prepared polylactic acid yarn polylactic acid micro-nano fibers are coated on the polylactic acid micron core yarn to form a multi-scale polylactic acid yarn;

[0045] (3) The obtained polylactic acid yarn is subjected to rib weave on a circular knitting machine to obtain a polylactic acid fabric.

[0046] Example 4

[0047] The preparation method of this embodiment is the same as that of embodiment 3, except that the rotation speed of the drum is 200 r / min.

[0048] Example 5

[0049] The preparation method of this embodiment is the same as that of embodiment 3, except that the rotation speed of the drum is 300 r / min.

[0050] Example 6

[0051] The preparation method of this embodiment is the same as that of embodiment 3, except that the rotation speed of the drum is 400 r / min.

[0052] The drum speeds of embodiments 3 to 6 are different, such as Figure 4 As shown, the different yarn twist angles are formed due to the different drum speeds. As the speed increases, the twist angle decreases.

[0053] Example 7

[0054] A method for preparing polylactic acid yarn is based on green solvent, and the specific steps are:

[0055] (1) at room temperature, preparing green organic solvents with a volume ratio of dimethyl carbonate / dimethylacetamide of 8:2 and a volume ratio of dimethyl carbonate / dimethylformamide of 7:3, respectively, adding polylactic acid powder to the two solvents, and stirring them in a water bath at 70° C. and a rotation speed of 200 r / min for 2 h to obtain PLA / DMC / DMAC spinning solutions with a mass fraction of 15 wt% and PLA / DMC / DMF spinning solutions with a mass fraction of 14 wt%, respectively;

[0056] (2) A PLA / DMC / DMAC spinning solution with a mass fraction of 15wt% and a PLA / DMC / DMF spinning solution with a mass fraction of 14wt% were respectively injected into two spinnerets of conjugated electrospinning, and the spinneret was set to push out the spinning solution at a stable flow rate of 1.5mL / h. The positive and negative pressures were both 8kV. In the case of coreless yarn, the spinning solution formed a stable triangular cone. At the same time, the speed of the collecting drum was set to 200r / min, and the receiving distance was 15cm to ensure that the polylactic acid micro-nano fiber became pure polylactic acid micro-nano yarn after forming the triangular cone. The spinning temperature was maintained within the range of 25±3℃, and the relative humidity was 65±5% to ensure the stability of the spinning process and the quality of the polylactic acid micro-nano fiber.

[0057] (3) The obtained polylactic acid micro-nano fibers are woven on a jet loom through a twill weave to obtain a polylactic acid fabric.

[0058] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing polylactic acid yarn, characterized in that: The following steps are involved: S1, dissolving polylactic acid powder in a solvent system containing dimethyl carbonate, stirring, and obtaining a polylactic acid spinning solution; S2. The polylactic acid spinning solution is subjected to conjugated electrospinning to obtain polylactic acid yarn.

2. The method for preparing a polylactic acid yarn according to claim 1, characterized in that: In step S1, the solvent system further contains dimethylformamide or dimethylacetamide; The volume ratio of dimethyl carbonate to dimethylformamide or dimethylacetamide in the solvent system is 1:0.1-1.

3. The method for preparing a polylactic acid yarn according to claim 1, characterized in that: In step S1, the mass fraction of polylactic acid in the polylactic acid spinning solution is 9-30wt%.

4. The method for preparing a polylactic acid yarn according to claim 1, characterized in that: In step S1, the stirring temperature is 25-100° C., and the stirring time is 0.5-10 h.

5. The method for preparing polylactic acid yarn according to claim 1, characterized in that: In step S2, the conjugate electrospinning condition parameters are: The flow rate of the spinneret is 0.01-10 mL / h, the positive and negative pressures are 3-40 kV respectively, the rotation speed of the collecting roller is 10-1000 r / min, the spinning distance is 5-50 cm, the spinning temperature is 0-35° C., and the relative humidity is 60-70%.

6. The method for preparing a polylactic acid yarn according to claim 1, characterized in that: In step S2, the polylactic acid spinning solution can also be subjected to conjugate electrospinning on the micron PLA core yarn, and the moving speed of the micron PLA core yarn is 0.1 to 20 mm / s.

7. A polylactic acid yarn obtained by the preparation method according to any one of claims 1 to 6, characterized in that: The diameter of the polylactic acid yarn is 10 to 1000 nm.

8. The polylactic acid yarn according to claim 7, characterized in that: The invention comprises a micron PLA core yarn and a micro-nano PLA skin layer coated on the micron PLA core yarn. The diameter of the micron PLA core yarn is 5-15 μm, and the diameter of the micro-nano PLA skin layer is 10-1000 nm.

9. A polylactic acid fabric, characterized in that: The polylactic acid yarn according to claim 7 or 8 is woven to obtain a polylactic acid fabric.

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