Preparation method of high-efficiency and high-quality fine denier type bio-based polymer melt-spun fiber

Abstract

The invention discloses a preparation method of high-efficiency and high-quality fine denier type bio-based polymer melt-spun fibers. The method comprises the following steps: (1) raw material pretreatment: drying bio-based polymer slices, and controlling the moisture content; (2) porous spinning and high-speed spinning: melting the slices obtained in the step (1) through a screw extruder, extruding through a porous spinneret plate, and quickly cooling through an air blowing system to form bio-based polymer melt-spun nascent fibers; (3) spinning-drafting one-step process: performing multi-stage drafting treatment and heat setting on the nascent fiber to improve the crystallinity and uniformity of the fiber; and (4) winding and forming the fine denier fiber: winding and forming the fine denier bio-based polymer melt-spun fiber obtained in the step (3) to obtain the high-quality bio-based polymer melt-spun fiber. The monofilament obtained by the method has enough fineness and excellent mechanical properties, can meet the requirements of subsequent processing such as weaving, is applied to the fields of clothing, decoration and industry, and has better application value.

Description

Technical Field

[0001] The invention belongs to the technical field of textile material processing, and in particular relates to a method for preparing high-efficiency and high-quality fine-denier bio-based polymer melt-spun fibers. Background Art

[0002] Chemical fiber is a flexible material with a certain fineness and aspect ratio, which is derived from natural or synthetic high molecular polymers. At present, chemical fiber is widely used in clothing, decoration, and industrial fields. In addition to the application of "beautifying clothing", chemical fiber textiles have penetrated into all aspects of our lives, from the sky (aerospace textiles), into the ground (geotechnical construction textiles), into the sea (marine fishery textiles), to human body applications (tissue organ textiles), and many other "fiber +" fields, cross-integration fields, and unknown (X) fields.

[0003] Many of the existing polymer raw materials for chemical fibers are petroleum-based polymers, such as polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyurethane (PU), etc. These petroleum-based polymers have high molecular weight, high chemical energy, and hydrophobic properties, making them difficult to be degraded by microorganisms, making the fiber materials of petroleum-based polymers degrade very slowly and will exist in nature for a long time, forming "white pollution".

[0004] With the increasing awareness of environmental protection and the growing demand for green fiber materials, the proportion of bio-based polymer fiber materials used in clothing, decoration, and industrial applications has shown a significant increase, and bio-based fiber materials are gradually being recognized and accepted by the market, and market demand is increasing. Bio-based polymer fiber materials are increasingly replacing petroleum-based fiber materials in more and more applications, and have become a highlight in leading technological innovation and economic development in the fiber field.

[0005] Existing bio-based polymers include different categories such as bio-based polyamide (PA11, PA12, etc.) and polylactic acid (PLA). For this type of bio-based polymer, the current melt-spun fibers are mainly used to prepare coarse denier fibers, modified bio-based polymer fibers (two-component or multi-component), and fibers produced by a two-step spinning-drawing process. The prepared bio-based polymer fibers have a coarse diameter, are not pure spinning, and have low production efficiency. The spinning-drawing two-step process has a low spinning speed and limited output. At the same time, the process is cumbersome and the cost is high, resulting in a shortage of supply in the market. The prepared coarse denier bio-based polymer melt-spun fibers have a coarse diameter, poor stability, and uneven product quality, and cannot form high-efficiency production and high-quality bio-based polymer melt-spun fibers.

[0006] Based on this, the present invention proposes a method for preparing high-efficiency, high-quality, fine-denier bio-based polymer melt-spun fibers. Through the integrated technology of multi-hole spinning, spinning-drawing one-step method, and high-speed spinning, a high-efficiency preparation process for bio-based polymers is formed; through a multi-stage drawing-winding system, the primary fibers prepared by the bio-based polymer melt-spinning technology are subjected to multi-stage drawing to achieve fiber stretching and thinning (effectively reducing the fiber diameter) and uniformity regulation, forming a high-quality production process for fine-denier bio-based polymer melt-spun fibers. Through multi-hole spinning, spinning-drawing one-step method, high-speed spinning, and multi-stage drawing-winding processes, the production efficiency and quality of pure spinning, fine-denier, bio-based polymer melt-spun fibers are significantly improved, forming the stability and uniformity of bio-based polymer fiber products. Summary of the invention

[0007] The purpose of the present invention is to provide a method for preparing high-efficiency and high-quality fine-denier bio-based polymer melt-spun fibers in view of the deficiencies of the prior art, so as to achieve high-efficiency and high-quality production of pure-spun, fine-denier, melt-spun fibers of bio-based polymers, and form stability and uniformity of bio-based polymer melt-spun fibers. Based on this, a high-efficiency preparation process for bio-based polymers is formed through the integrated technology of multi-hole spinning, spinning-drawing one-step method, and high-speed spinning; the primary fibers prepared by the bio-based polymer melt-spinning technology are multi-stage drawn through a multi-stage drawing-winding system to achieve fiber stretching, thinning, and uniformity regulation, and form high-quality production of fine-denier bio-based polymer melt-spun fibers.

[0008] The present invention is implemented by the following technical solutions:

[0009] A method for preparing high-efficiency, high-quality, fine-denier bio-based polymer melt-spun fibers comprises the following steps:

[0010] (1) Raw material pretreatment: drying the bio-based polymer (PLA or PA11) slices to control the moisture content;

[0011] (2) Multi-hole spinning: The dried bio-based polymer chips are melted by a screw extruder, extruded through a multi-hole spinneret, and rapidly cooled by a blowing system to form primary fibers;

[0012] (3) One-step spinning-drawing process: The primary fibers of bio-based polymers are subjected to multi-stage drawing, stretching, thinning and heat setting to obtain fine-denier fibers; the mechanical strength, uniformity and crystallinity of the fibers are improved by increasing the spinning speed and adjusting the drawing process conditions;

[0013] (4) Winding: The obtained fine denier fibers are continuously wound to form stable fiber bobbins, thereby obtaining high-quality fine denier bio-based polymer melt-spun fibers.

[0014] In the above technical solution, further, the moisture content of step (1) is controlled to be less than 0.003%. Excessive moisture content will lead to hydrolysis and degradation of bio-based polymers; molecular weight decreases, and molecular weight distribution uniformity deteriorates;

[0015] Furthermore, the multi-hole spinneret in step (2) has 10-100 holes, and the diameter of the spinneret holes is usually 0.2-0.7 mm.

[0016] Furthermore, the high-speed spinning speed of step (2) is ≥4200 m / min. The spinning speed has an important influence on the crystallinity and mechanical properties of the fiber. The higher the spinning speed, the higher the crystallinity and the more significant the mechanical property enhancement effect. During the high-speed spinning process, the bio-based polymer fiber is induced to crystallize and the mechanical properties are improved.

[0017] Furthermore, the stretching in step (3) is a multi-stage stretching, preferably at least three-stage stretching, with a total stretching multiple of 2-2.5, and the temperature of the hot roller in the heat setting is 70-110°C, and the hot roller speed is 2000-4300 m / min. The crystallinity and orientation of the nascent fibers of the bio-based polymer are relatively low. Through the multi-stage stretching process, the fiber fineness can be improved, fine denier fibers can be formed, the crystallinity can be increased, the mechanical properties can be enhanced, and the uniformity can be improved to form uniform bio-based polymer melt-spun fibers.

[0018] Compared with the prior art, the above method can efficiently produce high-quality fine-denier bio-based polymer melt-spun fibers.

[0019] The present invention pre-dries bio-based polymer PLA or PA11 slices to effectively remove moisture and prevent hydrolysis and degradation during melt processing; a porous spinning assembly is combined with a one-step high-speed spinning technology to directly prepare PLA and PA11 fibers, simplifying the production process and significantly improving production efficiency. Compared with the traditional method of coarse diameter, non-pure spinning, low production efficiency, limited output, and cumbersome procedures (such as the spinning-drawing two-step process), the present invention effectively solves the technical bottleneck that the coarse denier bio-based polymer melt-spun fibers prepared by the prior art are coarse in diameter, poor in stability, and uneven in product quality, and cannot form high-efficiency production and high-quality production. The porous spinning assembly is combined with a one-step high-speed spinning technology to simplify the production process and significantly improve production efficiency. The method ensures that the fiber has good orientation and crystallinity. The multi-stage drafting technology is used to adjust the fiber fineness and uniformity, improve mechanical properties, and improve fiber quality, so as to achieve fine denier, high-strength, homogenized, and high-quality bio-based polymer melt-spun fibers. The monofilament obtained by this method has sufficient fineness and excellent mechanical properties, can meet the needs of subsequent processing such as weaving, and is used in clothing, decoration, and industrial fields, and has good application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below in conjunction with the accompanying drawings:

[0021] Figure 1 The bio-based polymer PLA fiber prepared in Example 1;

[0022] Figure 2 The bio-based polymer PA11 fiber prepared in Example 3; Specific implementation methods

[0023] The present invention is further described below in conjunction with embodiments:

[0024] In the following examples, unless otherwise specified, the reagents, materials and equipment used can be purchased from commercial sources or prepared by conventional methods.

[0025] Example 1

[0026] (1) drying the bio-based polymer PLA slices, with a pre-crystallization temperature of 110° C., a crystallization time of 8 min, a drying temperature of 115° C., and a moisture content of 0.002%;

[0027] (2) The dried PLA slices are melted by a screw extruder, with the temperature of each section of the screw being 160-230° C., extruded through a 50-hole spinneret at a spinning speed of 4200 m / min, and rapidly cooled by a blowing system to form primary fibers;

[0028] (3) stretching and heat setting the spun fibers, with the hot roller speeds being 2300 m / min, 2800 m / min, 3600 m / min, and 4300 m / min, respectively, and the hot roller temperatures being 80°C, 90°C, 100°C, and 110°C, respectively, with a total stretching ratio of 2.0;

[0029] (4) The treated fibers are split and wound to form PLA packaged yarns at a winding speed of 4200 m / min. Figure 1 shown.

[0030] Example 2

[0031] (1) drying the bio-based polymer PLA slices, with a pre-crystallization temperature of 95° C., a crystallization time of 8 min, a drying temperature of 105° C., and a moisture content of 0.003%;

[0032] (2) The dried PLA slices are melted by a screw extruder, with the temperature of each section of the screw being 160-230° C., extruded through a 10-hole spinneret at a spinning speed of 4200 m / min, and rapidly cooled by a blowing system to form primary fibers;

[0033] (3) stretching and heat setting the spun fibers, with the hot roller speeds being 2000 m / min, 2600 m / min, 3500 m / min, and 4200 m / min, respectively, and the hot roller temperatures being 80°C, 90°C, 100°C, and 105°C, respectively, with a total stretching multiple of 2.1;

[0034] (4) The treated fibers are divided and wound to continuously form PLA packaged yarns at a winding speed of 4500 m / min.

[0035] Example 3

[0036] (1) Drying PA11 slices, with a pre-crystallization temperature of 110° C., a crystallization time of 10 min, a drying temperature of 100-120° C., and a moisture content of 0.002%;

[0037] (2) The dried PA11 slices are melted by a screw extruder, with the temperature of each section of the screw being 160-230°C, and then extruded through a 10-hole spinneret at a spinning speed of 4200 m / min, and rapidly cooled by a blowing system to form primary fibers;

[0038] (3) stretching and heat setting the spun fibers, with the hot roller speeds being 2400 m / min, 2800 m / min, 3700 m / min, and 4400 m / min, respectively, and the hot roller temperatures being 85°C, 95°C, 105°C, and 110°C, respectively, with a total stretching ratio of 2.0;

[0039] (4) PA11 fibers were prepared by multi-hole spinning, spinning-drawing one-step method, high-speed spinning, multi-stage drawing-winding process, and the winding speed was 4300m / min to obtain PA11 rolled fibers with normal winding, stable quality and uniformity. Figure 2 shown.

[0040] Example 4

[0041] (1) Drying PA11 slices, with a pre-crystallization temperature of 110° C., a crystallization time of 20 min, a drying temperature of 100-120° C., and a moisture content of 0.002%;

[0042] (2) The dried PA11 slices are melted by a screw extruder, with the temperature of each section of the screw being 160-230°C, and then extruded through a 50-hole spinneret at a spinning speed of 4200 m / min, and rapidly cooled by a blowing system to form primary fibers;

[0043] (3) stretching and heat setting the spun fibers, with the hot roller speeds being 2300 m / min, 2800 m / min, 3200 m / min, and 4500 m / min, respectively; the hot roller temperatures being 80°C, 95°C, 100°C, and 115°C, respectively; and the total stretching ratio being 2.0;

[0044] (4) The PA11 fiber was prepared by multi-hole spinning, spinning-drawing one-step method, high-speed spinning, and multi-stage drawing-winding process, with a winding speed of 4400m / min, and the PA11 rolled fiber with normal winding, stable quality and uniformity was obtained.

[0045] The properties of the bio-based polymer melt-spun fibers obtained in the above embodiments are shown in Table 1. The obtained fibers are fine denier, high strength, and uniform, and are high-quality bio-based polymer melt-spun fibers. The control of the moisture content of the slices, as well as the spinning temperature and speed, the temperature and speed of the hot roller, and the winding speed in the one-step spinning-drawing method are very important parameters. If the control is not appropriate, normal spinning, poor uniformity of thick sections and fine sections, or easy breakage and poor mechanical properties may occur. Compared with conventional methods, the present invention can not only obtain high-quality fibers, but also obtain monofilaments with sufficient fineness and excellent mechanical properties, and the method is efficient.

[0046] Table 1 Properties of bio-based polymer melt-spun fibers from different examples

[0047] Fineness / dtex Breaking strength / (cN / dtex) Elongation at break / % Example 1 (PLA) 24 3.20 34％ Example 2 (PLA) 27 3.32 32％ Example 3 (PA11) 24 3.9 89％ Example 4 (PA11) 27 4.12 87％

[0048] The above-described embodiments are only some of the preferred solutions of the present invention, but they are not intended to limit the present invention. A person skilled in the relevant technical field may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, any technical solution obtained by equivalent replacement or equivalent transformation falls within the protection scope of the present invention.

Claims

1. A method for preparing high-efficiency, high-quality, fine-denier bio-based polymer melt-spun fibers, characterized in that: The steps include: (1) Raw material pretreatment: drying the bio-based polymer slices to control the moisture content; the bio-based polymer is PLA or PA11; (2) Multi-hole spinning and high-speed spinning: The dried bio-based polymer slices are melted by a screw extruder, extruded through a multi-hole spinneret, and quickly cooled by a blowing system to form primary fibers; (3) One-step spinning-drawing process: The primary fibers are subjected to multi-stage drawing and heat setting to control their fineness, uniformity, crystallinity and mechanical properties to obtain fine denier fibers; (4) Winding: The fine denier fibers obtained in 3) are continuously wound to form high-quality fine denier bio-based polymer melt-spun fibers.

2. The method for preparing high-efficiency, high-quality, fine-denier bio-based polymer melt-spun fibers according to claim 1, characterized in that: The moisture content in step (1) is controlled to be less than 0.003%.

3. The method for preparing high-efficiency, high-quality, fine-denier bio-based polymer melt-spun fibers according to claim 1, characterized in that: The spinning speed of the high-speed spinning in step (2) is ≥4200 m / min.

4. The method for preparing high-efficiency, high-quality, fine-denier bio-based polymer melt-spun fibers according to claim 1, characterized in that: The porous spinneret in step (2) has 10-50 holes.

5. The method for preparing high-efficiency, high-quality, fine-denier bio-based polymer melt-spun fibers according to claim 1, characterized in that: The step (3) is a one-step spinning-drawing method and a multi-stage drawing process.

6. The method for preparing high-efficiency, high-quality, fine-denier bio-based polymer melt-spun fibers according to claim 1, characterized in that: In the heat setting of step (3), the temperature of the hot roller is 70-110° C. and the speed of the hot roller is 2000-4300 m / min.

7. The method for preparing high-efficiency, high-quality, fine-denier bio-based polymer melt-spun fibers according to claim 1, characterized in that: The total stretching ratio of step (3) is 2-2.

5.

8. The method for preparing high-efficiency, high-quality, fine-denier bio-based polymer melt-spun fibers according to claim 1, characterized in that: The fineness of the obtained bio-based polymer melt-spun fibers is 24-27 dtex.

9. The method for preparing high-efficiency, high-quality, fine-denier bio-based polymer melt-spun fibers according to claim 1, characterized in that: The breaking strength of the obtained bio-based polymer melt-spun fibers is 3.2-4.12 cN / dtex.

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