Preparation method for PLA / PHBV blend fiber

Abstract

The present invention relates to a preparation method for a PLA / PHBV blend fiber, comprising blending PLA and PHBV for melt spinning to obtain a PLA / PHBV blend fiber; wherein the intrinsic viscosity of PLA is 1.31-1.35 dL / g; the melt spinning comprises a curling process; process parameters of the melt spinning comprise: the temperature of a spinning box being 223-238°C, the pump supply capacity of a metering pump being 800-900 g / min, the post-spinning drafting speed being 110-120 m / min, and the curling temperature being 2-67°C; the mass content of PHBV in the PLA / PHBV blend fiber is 10-30%; and the breaking strength of the PLA / PHBV blend fiber is 3.4-3.9 cN / dtex. The preparation method of the present invention is simple, and the finally prepared PLA / PHBV blend fiber has good mechanical properties.

Description

A preparation method of PLA / PHBV blended fiber

[0001] This application claims the benefit of Chinese patent application No. 202311190832X, filed on September 15, 2023. This application incorporates the entirety of the aforementioned Chinese patent application. Technical Field

[0002] The invention belongs to the field of functional PLA fibers and relates to a method for preparing PLA / PHBV blended fibers. Background Art

[0003] Polylactic acid (PLA) is made from natural corn, cassava starch, or plant fibers through fermentation and polymerization processes. It is an aliphatic polyester and a crystalline, transparent, easily processable, and fully biodegradable thermoplastic polymer material. Its raw materials come from nature and can be completely degraded into water and carbon dioxide required by nature after being discarded, achieving a completely natural cycle. Therefore, PLA is expected to become a raw material for chemical fibers that replaces petroleum-based polymers, thereby solving the problems of resource shortages and environmental pollution faced by the development of synthetic fibers. However, in actual applications, PLA fibers have also exposed obvious shortcomings, such as low strength, poor hand feel, and limited antibacterial properties, which limit the application of PLA fibers in certain fields.

[0004] Polyhydroxybutyrate-valerate (PHBV) is a biopolyester produced from starch using fermentation technology. After being discarded, its products remain stable even in humid environments. In the presence of microorganisms, it degrades into carbon dioxide and water, posing no environmental risk. However, PHBV has poor melt spinnability and fiber mechanical properties. To expand the application of this biodegradable material in fields such as textiles, PLA and PHBV can be blended and modified to complement each other. PLA increases the material's strength, while PHBV improves its biodegradation rate and antibacterial properties.

[0005] Patent CN102181960A discloses a biodegradable fiber containing PHBV and a method for its preparation. This patent achieves good spinnability at low spinning manifold temperatures and high spinning speeds by vacuum-drying PHBV and PLA separately, physically mixing them in appropriate proportions, melt-spinning them, and performing post-processing. However, the resulting PLA / PHBV fiber has a maximum breaking strength of only 2.8 cN / dtex, limiting its application in spinning applications.

[0006] Patent CN105063789A discloses a PHBV / PLA bundled fiber. The fiber prepared in this patent is a blend of PHBV and PLA. The preparation method is as follows: the PHBV and PLA are mixed and melted, and then extruded through a spinneret. The fibers are then stretched 2 to 2.5 times and heat-set at 60 to 68°C. The extrusion speed can be 500 to 1500 m / min. Although the breaking strength of the PHBV / PLA bundled fiber described in this patent is relatively high, the actual measured strength does not exceed 2.8 cN / dtex.

[0007] In the literature "PLA / PHBV blend fiber structure and low-temperature dyeing performance [J]. Printing and Dyeing, 2018, No. 8.", PHBV and PLA were blended and spun to obtain PLA / PHBV blended fibers. After 20% PHBV was added to PLA, its breaking strength was only 1.95 cN / dtex.

[0008] The fiber used in the master's thesis "Analysis of the performance of PHBV / PLA biomass fibers and their spinnability [J]., 2018." is a PHBV / PLA blend fiber (30 / 70) provided by the Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences. Its breaking strength in dry and wet states is only 0.7 cN / dtex and 0.75 cN / dtex.

[0009] In summary, the breaking strength of PLA / PHBV blended fibers prepared using PLA and PHBV as raw materials in the prior art is relatively low.

[0010] Summary of the Invention

[0011] The purpose of the present invention is to solve the problems existing in the prior art and provide a method for preparing PLA / PHBV blended fibers.

[0012] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0013] A method for preparing a PLA / PHBV blend fiber comprises mixing PLA and PHBV and then melt-spinning the mixture to obtain the PLA / PHBV blend fiber.

[0014] The intrinsic viscosity of PLA is 1.31 to 1.35 dL / g;

[0015] Melt spinning includes a crimping process;

[0016] The melt spinning process parameters include: spinning box temperature 223-238°C, metering pump feed rate 800-900g / min, post-spinning draft speed 110-120m / min, and crimping temperature 62-67°C;

[0017] The mass content of PHBV in PLA / PHBV blended fibers is 10-30%;

[0018] The breaking strength of PLA / PHBV blended fibers is 3.4-3.9 cN / dtex.

[0019] The present invention solves a technical problem that people have long wanted to solve but have never been able to solve successfully by adjusting process parameters - the breaking strength of PLA / PHBV blended fibers prepared with PLA and PHBV as all raw materials (no other substances except these two substances) is low. Specifically, the present invention adjusts the spinning manifold temperature. The lower the spinning manifold temperature, on the one hand, it can avoid the degradation of PLA caused by free radicals generated by the degradation of PHBV, and on the other hand, it can avoid excessive melt fluidity, resulting in uneven cooling and poor fiber crystallization performance, which in turn leads to reduced fiber strength. The present invention adjusts the metering pump supply, and the metering pump supply is lower than that of the prior art. This is because the spinning A drop in the box temperature will lead to a decrease in melt fluidity. If the original pump supply is maintained, the fiber fineness will be correspondingly high. The present invention adjusts the post-spinning drafting speed, which is relatively low. A lower speed can extend the heat setting time of PHBV / PLA fibers. The extension of the heat setting time can increase the crystallinity of the fibers, thereby enhancing the strength of the fibers. The post-spinning drafting speed should not be too low, otherwise, on the one hand, it will cause an increase in production costs. On the other hand, if the spinning speed is too slow, the fibers will stay on the roller for too long, which will also cause partial degradation. The present invention adjusts the curling temperature, which should not be too high, otherwise, it will easily cause fiber shrinkage, poor stability of the molecular chains in the fibers, and reduced strength.

[0020] As the preferred technical solution:

[0021] The preparation method of the PLA / PHBV blend fiber as described above comprises the following specific steps:

[0022] (1) Fully dry the PLA slices and PHBV slices;

[0023] (2) The dried PLA chips and PHBV chips are mixed and then melt-extruded, spun, cooled by annular air blowing, wound, and formed into raw yarns;

[0024] (3) The raw silk is subjected to secondary drawing, curling and cutting in sequence to obtain PLA / PHBV blended fibers.

[0025] In the method for preparing a PLA / PHBV blended fiber as described above, in step (1), the drying temperature is 116° C., the drying time is about 14 hours, and the moisture content of each slice after drying is less than 200 ppm.

[0026] In the method for preparing a PLA / PHBV blended fiber as described above, in step (2), the temperature of each zone of the screw extruder is 215°C to 245°C, the annular air temperature is 27°C, the annular air inlet pressure is 650-750 Pa, and the winding speed is 1050-1100 m / min.

[0027] In the method for preparing a PLA / PHBV blended fiber as described above, in step (2), the temperatures of zones 1 to 6 of the screw extruder are 220°C, 222°C, 227°C, 232°C, 227°C, and 222°C, or 220°C, 225°C, 230°C, 235°C, 230°C, and 225°C, or 220°C, 230°C, 235°C, 240°C, 235°C, and 230°C; the six zones of the screw extruder are divided into three sections, namely, a feeding zone, a melting zone, and a metering zone. The temperature settings of the six zones are generally the lowest in the feeding zone, which is to ensure that the slices are continuously transported to the melting zone through the extrusion of the screw in the early stage; the temperature of the melting zone is the highest to ensure that the slices are completely melted, and the temperature of the metering zone is slightly lower than that of the melting zone, which is to ensure that the melt viscosity is stably transported to the spinning manifold. The temperature difference between the six zones of the screw is about 3 to 5 degrees. The temperature settings of the six zones are related to the melting point of the melt and are set in combination with the rheological properties during the processing.

[0028] In the method for preparing a PLA / PHBV blended fiber as described above, in step (2), the spinneret holes used in the spinning are one or more of the following: a W-shaped, a cross-shaped, a trilobal-shaped, and a four-T-shaped hole; fiber profiling can improve the glossiness, softness, and moisture absorption and perspiration permeability of the fiber, thereby improving the wearing performance of the PLA fiber and expanding its scope of use, and has good development prospects; fiber profiling can further enhance the antibacterial properties of the fiber, because after fiber profiling, the moisture absorption and perspiration permeability of the fiber are enhanced, thereby weakening the environment for bacterial growth.

[0029] In the method for preparing a PLA / PHBV blend fiber as described above, in step (3), the temperature of the secondary drawing is 62±2° C., and the multiple of the secondary drawing is 3.02 to 3.35 times.

[0030] The PLA / PHBV blend fiber preparation method as described above has a fineness of 2.17 to 2.32 dtex, a crimp number of 9.1 to 10.9 per 25 mm, a crimp rate of 8.4 to 11.3%, an elongation at break of 39.5 to 48.9%, an antibacterial rate against Staphylococcus aureus exceeding 97%, and an antibacterial rate against Escherichia coli exceeding 96.5%. Beneficial effects:

[0031] The present invention provides a method for preparing PLA / PHBV blended fibers with good spinnability, excellent mechanical properties and comprehensive performance.

[0032] The PLA / PHBV blend fiber product of the present invention has high quality, good spinnability and mechanical properties. The maximum breaking strength can reach 3.9 cN / dtex, which is 56% higher than the fiber breaking strength of the disclosed patent CN102181960A. At the same time, the elongation at break also reaches 48.9%, greatly expanding the spinning application range of PLA fibers. In addition, compared with the spinning process of PLA fibers, the PLA / PHBV blend fiber still has good spinnability at a lower spinneret temperature, which can effectively improve production efficiency and reduce costs.

[0033] To further enhance the mechanical properties and comfort of PLA fibers, the present invention adjusts the process to improve the mechanical properties while using the profiled treatment of the fibers to improve their properties such as luster, bulkiness, air permeability, elasticity, and hand feeling, further improving the wearing performance of PLA fibers. Brief Description of the Drawings

[0034] Figure 1 is a schematic cross-sectional view of a PLA / PHBV blend fiber prepared with a king-shaped spinneret hole according to the present invention;

[0035] Figure 2 is a schematic cross-sectional view of a PLA / PHBV blend fiber prepared with a cross-shaped spinneret hole according to the present invention;

[0036] Figure 3 is a schematic cross-sectional view of a PLA / PHBV blend fiber prepared with a three-leaf-shaped spinneret hole according to the present invention;

[0037] Figure 4 is a schematic cross-sectional view of a PLA / PHBV blend fiber prepared with a four-T-shaped spinneret hole according to the present invention. Detailed Embodiments

[0038] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0039] The following are the test methods for some performance indicators in each embodiment:

[0040] Fineness: Measured in accordance with GB / T 14336-2008.

[0041] Elongation at break: Measured in accordance with GB / T 14337-2022.

[0042] Breaking strength: Measured in accordance with GB / T 14337-2022.

[0043] Curl number and curl rate: measured in accordance with GB / T 14338-2022.

[0044] Antibacterial rate against Staphylococcus aureus: determined in accordance with GB / T 20944.3-2008 standard.

[0045] Antibacterial rate against Staphylococcus aureus: determined in accordance with GB / T 20944.3-2008 standard.

[0046] Example 1

[0047] A method for preparing a PLA / PHBV blend fiber comprises the following steps:

[0048] (1) Preparation of raw materials:

[0049] PLA chips: Manufacturer: Total Corbivir Polylactic Acid, brand L130, intrinsic viscosity 1.32 dL / g;

[0050] PHBV slices: The manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., brand name is Y1000P;

[0051] (2) PLA slices and PHBV slices were dried at 116°C until the moisture content of each slice was 120 ppm;

[0052] (3) The dried PLA chips and PHBV chips are mixed and then melt-extruded, spun, cooled by annular air blowing, wound, and formed into raw yarns;

[0053] The temperature of the screw extruder zone 1 is 220°C, the temperature of the zone 2 is 230°C, the temperature of the zone 3 is 235°C, the temperature of the zone 4 is 240°C, the temperature of the zone 5 is 235°C, the temperature of the zone 6 is 230°C, the temperature of the spinning box is 233°C, the metering pump supply is 880g / min, the annular air temperature is 27°C, the annular air inlet pressure is 730Pa, and the winding speed is 1050m / min;

[0054] The spinneret used for spinning has a cross-shaped spinneret hole with 1200 holes.

[0055] (4) The raw silk was subjected to secondary drawing, crimping, and cutting in sequence to obtain PLA / PHBV blended fibers; wherein the post-spinning drawing speed was 115 m / min, the secondary drawing temperature was 62°C, the secondary drawing multiple was 3.06 times, the crimping temperature was 65°C, and the mass content of PHBV in the PLA / PHBV blended fibers was 10%.

[0056] The cross-section of the final PLA / PHBV blended fiber is shown in Figure 2. Its fineness is 2.3 dtex, the elongation at break is 48.9%, the breaking strength is 3.9 cN / dtex, the number of crimps is 9.1 / 25 mm, the crimp rate is 8.4%, the antibacterial rate against Staphylococcus aureus is 97.1%, and the antibacterial rate against Escherichia coli is 96.5%.

[0057] Comparative Example 1

[0058] A method for preparing a PLA / PHBV blend fiber is basically the same as that in Example 1, except that the spinning box temperature is 260°C.

[0059] The final PLA / PHBV blended fiber has a fineness of 2.3dtex, an elongation at break of 47.8%, a breaking strength of 3.2cN / dtex, a crimp number of 10.8 / 25mm, a crimp rate of 11.6%, an antibacterial rate against Staphylococcus aureus of 93.1%, and an antibacterial rate against Escherichia coli of 91.5%.

[0060] By comparing Example 1 with Comparative Example 1, it can be seen that in Comparative Example 1, the spinning box temperature is too high during the melt spinning process, which will lead to a decrease in fiber strength and a decrease in antibacterial properties. This is because the excessively high spinning temperature will not only cause the degradation of PHBV and cause a decrease in antibacterial properties, but also, when other process parameters remain unchanged, the excessively high spinning box temperature will prevent the PLA melt from fully cooling and crystallizing in time, thereby leading to a decrease in fiber strength.

[0061] Comparative Example 2

[0062] A method for preparing a PLA / PHBV blend fiber is basically the same as that in Example 1, except that the post-spinning drafting speed is 130 m / min.

[0063] The final PLA / PHBV blended fiber has a fineness of 2.3dtex, an elongation at break of 46.43%, a breaking strength of 3.0cN / dtex, a crimp number of 9.8 / 25mm, a crimp rate of 10.2%, an antibacterial rate against Staphylococcus aureus of 97.3%, and an antibacterial rate against Escherichia coli of 96.7%.

[0064] By comparing Example 1 and Comparative Example 2, it can be seen that in Comparative Example 2, the post-spinning drawing speed is too fast during the melt spinning process, which will lead to a decrease in the fiber breaking strength. This is because the drawing speed is too fast, the residence time of the fiber on the heat setting roller is reduced, the heat setting time is reduced, and the crystal stability of the fiber after orientation becomes poor, resulting in a decrease in fiber strength.

[0065] Comparative Example 3

[0066] A method for preparing a PLA / PHBV blend fiber is basically the same as that in Example 1, except that the crimping temperature is 80°C.

[0067] The final PLA / PHBV blended fiber has a fineness of 2.3dtex, an elongation at break of 40.28%, a breaking strength of 2.8cN / dtex, a crimp number of 11.1 / 25mm, a crimp rate of 12.0%, an antibacterial rate against Staphylococcus aureus of 95.7%, and an antibacterial rate against Escherichia coli of 95.2%.

[0068] By comparing Example 1 and Comparative Example 3, it can be seen that since the curling temperature of Comparative Example 3 is too high during the melt spinning process, the curl number and curl rate will increase. This is because the curling temperature is too high, the movement of the molecular chains in the amorphous region of the fiber is greater, and when passing through the winder, after physical extrusion, the fiber deformation is greater, which is manifested as an increase in the curl number and curl rate. At the same time, since the curling temperature is too high, the movement of the molecular chains in the amorphous region is enhanced, which destroys the stability of the crystalline region and also causes a decrease in fiber strength.

[0069] Example 2

[0070] A method for preparing a PLA / PHBV blend fiber comprises the following steps:

[0071] (1) Preparation of raw materials:

[0072] PLA chips: Manufacturer: Total Corbivir Polylactic Acid, brand L130, intrinsic viscosity 1.31 dL / g;

[0073] PHBV slices: The manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., brand name is Y1000P;

[0074] (2) PLA slices and PHBV slices were dried at 116°C until the moisture content of each slice was 120 ppm;

[0075] (3) The dried PLA chips and PHBV chips are mixed and then melt-extruded, spun, cooled by annular air blowing, wound, and formed into raw yarns;

[0076] The temperature of the screw extruder zone 1 is 220°C, the temperature of the zone 2 is 225°C, the temperature of the zone 3 is 230°C, the temperature of the zone 4 is 235°C, the temperature of the zone 5 is 230°C, the temperature of the zone 6 is 225°C, the temperature of the spinning box is 230°C, the metering pump supply is 880g / min, the annular air temperature is 27°C, the annular air inlet pressure is 730Pa, and the winding speed is 1050m / min;

[0077] The spinneret used for spinning has a cross-shaped spinneret hole with 1200 holes.

[0078] (4) The raw silk was subjected to secondary drawing, crimping, and cutting in sequence to obtain PLA / PHBV blended fibers; wherein the post-spinning drawing speed was 115 m / min, the secondary drawing temperature was 62°C, the secondary drawing multiple was 3.1 times, the crimping temperature was 65°C, and the mass content of PHBV in the PLA / PHBV blended fibers was 10%.

[0079] The final PLA / PHBV blended fiber has a fineness of 2.22 dtex, an elongation at break of 48.8%, a breaking strength of 3.5 cN / dtex, a crimp number of 10.1 / 25 mm, a crimp rate of 10.7%, an antibacterial rate against Staphylococcus aureus of 97.3%, and an antibacterial rate against Escherichia coli of 96.7%.

[0080] Example 3

[0081] A method for preparing a PLA / PHBV blend fiber comprises the following steps:

[0082] (1) Preparation of raw materials:

[0083] PLA chips: Manufacturer: Total Corbivir Polylactic Acid, brand L130, intrinsic viscosity 1.35 dL / g;

[0084] PHBV slices: The manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., brand name is Y1000P;

[0085] (2) PLA slices and PHBV slices were dried at 116°C until the moisture content of each slice was 100 ppm;

[0086] (3) The dried PLA chips and PHBV chips are mixed and then melt-extruded, spun, cooled by annular air blowing, wound, and formed into raw yarns;

[0087] The temperature of the screw extruder zone 1 is 220°C, the temperature of the zone 2 is 235°C, the temperature of the zone 3 is 240°C, the temperature of the zone 4 is 245°C, the temperature of the zone 5 is 240°C, the temperature of the zone 6 is 235°C, the temperature of the spinning box is 238°C, the metering pump supply is 880g / min, the annular air temperature is 27°C, the annular air inlet pressure is 730Pa, and the winding speed is 1100m / min;

[0088] The spinneret used for spinning has a cross-shaped spinneret hole with 1200 holes.

[0089] (4) The raw silk was subjected to secondary drawing, crimping, and cutting in sequence to obtain PLA / PHBV blended fibers; wherein the post-spinning drawing speed was 115 m / min, the secondary drawing temperature was 62°C, the secondary drawing multiple was 3.02 times, the crimping temperature was 62°C, and the mass content of PHBV in the PLA / PHBV blended fibers was 10%.

[0090] The final PLA / PHBV blended fiber has a fineness of 2.17 dtex, an elongation at break of 48.3%, a breaking strength of 3.7 cN / dtex, a crimp number of 9.3 / 25mm, a crimp rate of 8.5%, an antibacterial rate against Staphylococcus aureus of 97.2%, and an antibacterial rate against Escherichia coli of 96.5%.

[0091] Example 4

[0092] A method for preparing a PLA / PHBV blend fiber comprises the following steps:

[0093] (1) Preparation of raw materials:

[0094] PLA chips: Manufacturer: Total Corbivir Polylactic Acid, brand L130, intrinsic viscosity 1.34 dL / g;

[0095] PHBV slices: The manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., brand name is Y1000P;

[0096] (2) PLA slices and PHBV slices were dried at 116°C until the moisture content of each slice was 100 ppm;

[0097] (3) The dried PLA chips and PHBV chips are mixed and then melt-extruded, spun, cooled by annular air blowing, wound, and formed into raw yarns;

[0098] The temperature of the screw extruder zone 1 is 220°C, the temperature of the zone 2 is 230°C, the temperature of the zone 3 is 235°C, the temperature of the zone 4 is 240°C, the temperature of the zone 5 is 235°C, the temperature of the zone 6 is 230°C, the temperature of the spinning box is 230°C, the metering pump supply is 880g / min, the annular air temperature is 27°C, the annular air inlet pressure is 730Pa, and the winding speed is 1050m / min;

[0099] The spinneret used for spinning has a cross-shaped spinneret hole with 1200 holes.

[0100] (4) The raw silk was subjected to secondary drawing, crimping, and cutting in sequence to obtain PLA / PHBV blended fibers; wherein the post-spinning drawing speed was 115 m / min, the secondary drawing temperature was 61°C, the secondary drawing multiple was 3.08 times, the crimping temperature was 65°C, and the mass content of PHBV in the PLA / PHBV blended fibers was 20%.

[0101] The final PLA / PHBV blended fiber has a fineness of 2.32 dtex, an elongation at break of 42.4%, a breaking strength of 3.4 cN / dtex, a crimp number of 10.9 / 25mm, a crimp rate of 11.3%, an antibacterial rate against Staphylococcus aureus of 98.2%, and an antibacterial rate against Escherichia coli of 97.9%.

[0102] Example 5

[0103] A method for preparing a PLA / PHBV blend fiber comprises the following steps:

[0104] (1) Preparation of raw materials:

[0105] PLA chips: Manufacturer: Total Corbivir Polylactic Acid, brand L130, intrinsic viscosity 1.32 dL / g;

[0106] PHBV slices: The manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., brand name is Y1000P;

[0107] (2) PLA slices and PHBV slices were dried at 116°C until the moisture content of each slice was 160 ppm;

[0108] (3) The dried PLA chips and PHBV chips are mixed and then melt-extruded, spun, cooled by annular air blowing, wound, and formed into raw yarns;

[0109] The temperature of the screw extruder zone 1 is 220°C, the temperature of the zone 2 is 230°C, the temperature of the zone 3 is 235°C, the temperature of the zone 4 is 240°C, the temperature of the zone 5 is 235°C, the temperature of the zone 6 is 230°C, the temperature of the spinning box is 230°C, the metering pump supply is 850g / min, the annular air temperature is 27°C, the annular air inlet pressure is 700Pa, and the winding speed is 1100m / min;

[0110] The spinneret used for spinning has a cross-shaped spinneret hole with 1200 holes.

[0111] (4) The raw silk was subjected to secondary drawing, crimping, and cutting in sequence to obtain PLA / PHBV blended fibers; wherein the post-spinning drawing speed was 115 m / min, the secondary drawing temperature was 62°C, the secondary drawing multiple was 3.1 times, the crimping temperature was 65°C, and the mass content of PHBV in the PLA / PHBV blended fibers was 25%.

[0112] The final PLA / PHBV blended fiber has a fineness of 2.18 dtex, an elongation at break of 39.5%, a breaking strength of 3.4 cN / dtex, a crimp number of 9.8 / 25mm, a crimp rate of 9%, an antibacterial rate against Staphylococcus aureus of 98.3%, and an antibacterial rate against Escherichia coli of 98%.

[0113] Example 6

[0114] A method for preparing a PLA / PHBV blend fiber comprises the following steps:

[0115] (1) Preparation of raw materials:

[0116] PLA chips: Manufacturer: Total Corbivir Polylactic Acid, brand L130, intrinsic viscosity 1.33 dL / g;

[0117] PHBV slices: The manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., brand name is Y1000P;

[0118] (2) PLA slices and PHBV slices were dried at 116°C until the moisture content of each slice was 110 ppm;

[0119] (3) The dried PLA chips and PHBV chips are mixed and then melt-extruded, spun, cooled by annular air blowing, wound, and formed into raw yarns;

[0120] The temperature of the screw extruder zone 1 is 220°C, the temperature of the zone 2 is 227°C, the temperature of the zone 3 is 232°C, the temperature of the zone 4 is 237°C, the temperature of the zone 5 is 232°C, the temperature of the zone 6 is 227°C, the temperature of the spinning box is 230°C, the metering pump supply is 850g / min, the annular air temperature is 27°C, the annular air inlet pressure is 700Pa, and the winding speed is 1050m / min;

[0121] The spinneret used for spinning has a cross-shaped spinneret hole with 1200 holes.

[0122] (4) The raw filaments are successively subjected to secondary drawing, crimping, and cutting to obtain PLA / PHBV blend fibers; among them, the post-spinning drawing speed is 115 m / min, the temperature of secondary drawing is 63 °C, the multiple of secondary drawing is 3.18 times, the crimping temperature is 65 °C, and the mass content of PHBV in the PLA / PHBV blend fibers is 30%.

[0123] The fineness of the finally obtained PLA / PHBV blend fibers is 2.2 dtex, the elongation at break is 40.4%, the breaking strength is 3.7 cN / dtex, the crimp number is 10.4 pieces / 25 mm, the crimp percentage is 11.1%, the antibacterial rate against Staphylococcus aureus is 99%, and the antibacterial rate against Escherichia coli is 99.3%.

[0124] Example 7

[0125] A preparation method of PLA / PHBV blend fibers is as follows:

[0126] (1) Preparation of raw materials:

[0127] PLA chips: The manufacturer is Total Corbion Polylactic Acid Company, the grade is L130, and the intrinsic viscosity is 1.32 dL / g;

[0128] PHBV chips: The manufacturer is Nanjing Hosu Era Antibacterial Material Technology Group Co., Ltd., and the grade is Y1000P;

[0129] (2) The PLA chips and PHBV chips are respectively dried at 116 °C until the moisture content of each chip is 170 ppm;

[0130] (3) After mixing the dried PLA chips and PHBV chips, they are successively melt-extruded, spun, cooled by ring blowing, wound, and formed by a screw extruder to obtain raw filaments;

[0131] The temperature of the first zone of the screw extruder is 220 °C, the temperature of the second zone is 222 °C, the temperature of the third zone is 227 °C, the temperature of the fourth zone is 232 °C, the temperature of the fifth zone is 227 °C, the temperature of the sixth zone is 222 °C, the temperature of the spinning box is 225 °C, the pump supply rate of the metering pump is 800 g / min, the temperature of the ring blowing is 27 °C, the inlet air pressure of the ring blowing is 650 Pa, and the winding speed is 1050 m / min;

[0132] The shape of the spinneret holes in the spinneret used for spinning is king-shaped, and the number of holes is 720;

[0133] (4) The raw silk was subjected to secondary drawing, crimping, and cutting in sequence to obtain PLA / PHBV blended fibers; wherein the post-spinning drawing speed was 110 m / min, the secondary drawing temperature was 62°C, the secondary drawing multiple was 3.09 times, the crimping temperature was 63°C, and the mass content of PHBV in the PLA / PHBV blended fibers was 10%.

[0134] The cross-section of the final PLA / PHBV blended fiber is shown in Figure 1. Its fineness is 2.28 dtex, the elongation at break is 43.2%, the breaking strength is 3.4 cN / dtex, the number of crimps is 9.8 / 25mm, the crimp rate is 9.8%, the antibacterial rate against Staphylococcus aureus is 97.4%, and the antibacterial rate against Escherichia coli is 97.7%.

[0135] Example 8

[0136] A method for preparing a PLA / PHBV blend fiber comprises the following steps:

[0137] (1) Preparation of raw materials:

[0138] PLA chips: Manufacturer: Total Corbivir Polylactic Acid, brand L130, intrinsic viscosity 1.34 dL / g;

[0139] PHBV slices: The manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., brand name is Y1000P;

[0140] (2) PLA slices and PHBV slices were dried at 116°C until the moisture content of each slice was 110 ppm;

[0141] (3) The dried PLA chips and PHBV chips are mixed and then melt-extruded, spun, cooled by annular air blowing, wound, and formed into raw yarns;

[0142] The temperature of the screw extruder zone 1 is 215°C, the temperature of the zone 2 is 220°C, the temperature of the zone 3 is 225°C, the temperature of the zone 4 is 230°C, the temperature of the zone 5 is 225°C, the temperature of the zone 6 is 220°C, the temperature of the spinning box is 223°C, the metering pump supply is 900g / min, the annular air temperature is 27°C, the annular air inlet pressure is 750Pa, and the winding speed is 1100m / min;

[0143] The spinneret used for spinning has a trilobal shape with 1800 holes.

[0144] (4) The raw silk was subjected to secondary drawing, crimping, and cutting in sequence to obtain PLA / PHBV blended fibers; wherein the post-spinning drawing speed was 120 m / min, the secondary drawing temperature was 64°C, the secondary drawing multiple was 3.35 times, the crimping temperature was 67°C, and the mass content of PHBV in the PLA / PHBV blended fibers was 10%.

[0145] The cross-section of the final PLA / PHBV blended fiber is shown in Figure 3. Its fineness is 2.24 dtex, the elongation at break is 44.4%, the breaking strength is 3.6 cN / dtex, the number of crimps is 9.7 / 25mm, the crimp rate is 10.3%, the antibacterial rate against Staphylococcus aureus is 97.7%, and the antibacterial rate against Escherichia coli is 97.3%.

[0146] Example 9

[0147] A method for preparing a PLA / PHBV blend fiber comprises the following steps:

[0148] (1) Preparation of raw materials:

[0149] PLA chips: Manufacturer: Total Corbivir Polylactic Acid, brand L130, intrinsic viscosity 1.35 dL / g;

[0150] PHBV slices: The manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., brand name is Y1000P;

[0151] (2) PLA slices and PHBV slices were dried at 116°C until the moisture content of each slice was 180 ppm;

[0152] (3) The dried PLA chips and PHBV chips are mixed and then melt-extruded, spun, cooled by annular air blowing, wound, and formed into raw yarns;

[0153] The temperature of the screw extruder zone 1 is 215°C, the temperature of the zone 2 is 220°C, the temperature of the zone 3 is 225°C, the temperature of the zone 4 is 230°C, the temperature of the zone 5 is 225°C, the temperature of the zone 6 is 220°C, the temperature of the spinning box is 223°C, the metering pump supply is 880g / min, the annular air temperature is 27°C, the annular air inlet pressure is 730Pa, and the winding speed is 1100m / min;

[0154] The spinneret used for spinning has a four-T shape and 1200 holes.

[0155] (4) The raw silk was subjected to secondary drawing, crimping, and cutting in sequence to obtain PLA / PHBV blended fibers; wherein the post-spinning drawing speed was 115 m / min, the secondary drawing temperature was 62°C, the secondary drawing multiple was 3.31 times, the crimping temperature was 65°C, and the mass content of PHBV in the PLA / PHBV blended fibers was 10%.

[0156] The cross-section of the final PLA / PHBV blended fiber is shown in Figure 4. Its fineness is 2.19 dtex, the elongation at break is 45.1%, the breaking strength is 3.5 cN / dtex, the number of crimps is 10.2 / 25mm, the crimp rate is 10.6%, the antibacterial rate against Staphylococcus aureus is 97.5%, and the antibacterial rate against Escherichia coli is 97.6%.

[0157] Example 10

[0158] A method for preparing a PLA / PHBV blend fiber is basically the same as that of Example 9, except that the spinneret holes used in the spinning are circular.

[0159] The cross-section of the final PLA / PHBV blended fiber is shown in Figure 4. Its fineness is 2.22 dtex, the elongation at break is 42.5%, the breaking strength is 3.7 cN / dtex, the number of crimps is 10.4 / 25 mm, the crimp rate is 9.9%, the antibacterial rate against Staphylococcus aureus is 97.4%, and the antibacterial rate against Escherichia coli is 97.3%.

[0160] Example 11

[0161] A method for preparing a PLA / PHBV blend fiber comprises the following steps:

[0162] (1) Preparation of raw materials:

[0163] PLA chips: Manufacturer: Total Corbivir Polylactic Acid, brand L130, intrinsic viscosity 1.33 dL / g;

[0164] PHBV slices: The manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., brand name is Y1000P;

[0165] (2) PLA slices and PHBV slices were dried at 116°C until the moisture content of each slice was 120 ppm;

[0166] (3) The dried PLA chips and PHBV chips are mixed and then melt-extruded, spun, cooled by annular air blowing, wound, and formed into raw yarns;

[0167] The temperature of the screw extruder zone 1 is 225°C, the temperature of the zone 2 is 230°C, the temperature of the zone 3 is 235°C, the temperature of the zone 4 is 240°C, the temperature of the zone 5 is 235°C, the temperature of the zone 6 is 230°C, the temperature of the spinning box is 235°C, the metering pump supply is 850g / min, the annular air temperature is 27°C, the annular air inlet pressure is 700Pa, and the winding speed is 1050m / min;

[0168] The spinneret used for spinning has two shapes: cross and chevron. The number of holes in the cross shape is 1200, and the number of holes in the chevron shape is 720.

[0169] (4) The raw silk was subjected to secondary drawing, crimping, and cutting in sequence to obtain PLA / PHBV blended fibers; wherein the post-spinning drawing speed was 115 m / min, the secondary drawing temperature was 60°C, the secondary drawing multiple was 3.27 times, the crimping temperature was 65°C, and the mass content of PHBV in the PLA / PHBV blended fibers was 10%.

[0170] The final PLA / PHBV blended fiber has a fineness of 2.27 dtex, an elongation at break of 41.7%, a breaking strength of 3.4 cN / dtex, a crimp number of 9.6 / 25mm, a crimp rate of 10.4%, an antibacterial rate against Staphylococcus aureus of 97%, and an antibacterial rate against Escherichia coli of 97.1%.

[0171] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. However, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A method for preparing a PLA / PHBV blended fiber, characterized in that: PLA and PHBV are mixed and melt-spun to obtain PLA / PHBV blended fibers; The intrinsic viscosity of PLA is 1.31 to 1.35 dL / g; Melt spinning includes a crimping process; The process parameters of melt spinning include: spinning box temperature 223-238°C, metering pump supply 800-900g / min, post-spinning drafting speed 110-120m / min, crimping temperature 62-67°C; The mass content of PHBV in PLA / PHBV blended fibers is 10-30%; The breaking strength of PLA / PHBV blended fibers is 3.4-3.9 cN / dtex.

2. The method for preparing a PLA / PHBV blended fiber according to claim 1, characterized in that: The specific steps are as follows: (1) Drying the PLA slices and PHBV slices separately; (2) mixing the dried PLA slices and PHBV slices and sequentially performing melt extrusion, spinning, ring-blowing cooling, winding, and molding to obtain raw yarn; (3) The raw silk is subjected to secondary drawing, curling and cutting in sequence to obtain PLA / PHBV blended fibers.

3. The method for preparing a PLA / PHBV blended fiber according to claim 2, characterized in that: In step (1), the drying temperature is 116° C., and the moisture content of each slice after drying is less than 200 ppm.

4. The method for preparing a PLA / PHBV blended fiber according to claim 2, characterized in that: In step (2), the temperature of each zone of the screw extruder is 215°C to 245°C, the annular air temperature is 27°C, the annular air inlet pressure is 650 to 750 Pa, and the winding speed is 1050 to 1100 m / min.

5. The method for preparing a PLA / PHBV blended fiber according to claim 4, characterized in that: In step (2), the temperatures in zones 1 to 6 of the screw extruder are 220°C, 222°C, 227°C, 232°C, 227°C, 222°C, or are 220°C, 225°C, 230°C, 235°C, 230°C, 225°C, or are 220°C, 230°C, 235°C, 240°C, 235°C, 230°C.

6. The method for preparing a PLA / PHBV blended fiber according to claim 2, characterized in that: In step (2), the spinneret holes in the spinneret used for spinning are one or more of the following types: a W-shaped, a cross-shaped, a trilobal-shaped, and a quad-T-shaped hole.

7. The method for preparing a PLA / PHBV blended fiber according to claim 2, characterized in that: In step (3), the temperature of the secondary stretching is 62±2° C., and the multiple of the secondary stretching is 3.02 to 3.35 times.

8. The method for preparing a PLA / PHBV blended fiber according to claim 1, characterized in that: The fineness of PLA / PHBV blended fiber is 2.17-2.32 dtex, the number of crimps is 9.1-10.9 / 25mm, the crimp rate is 8.4-11.3%, the elongation at break is 39.5-48.9%, the antibacterial rate against Staphylococcus aureus is over 97%, and the antibacterial rate against Escherichia coli is over 96.5%.

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