CN117026420B - A method for preparing PLA/PHBV blended fiber - Google Patents

Abstract

The invention relates to a preparation method of a PLA/PHBV blended fiber, wherein PLA and PHBV are mixed and melt-spun to obtain the PLA/PHBV blended fiber; the intrinsic viscosity of PLA is 1.31-1.35 dL/g; the melt spinning includes a curling process; the process parameters of the melt spinning include: a spinning box temperature of 223-238°C, a metering pump supply of 800-900 g/min, a post-spinning drafting speed of 110-120 m/min, and a curling temperature of 62-67°C; the mass content of PHBV in the PLA/PHBV blended fiber is 10-30%; and the breaking strength of the PLA/PHBV blended fiber is 3.4-3.9 cN/dtex. The preparation method of the invention is simple, and the PLA/PHBV blended fiber finally obtained has good mechanical properties.

Description

A method for preparing PLA/PHBV blended fiber

Technical Field

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

Background Art

Polylactic acid (PLA) is made from natural corn, cassava starch or plant fiber through fermentation, polymerization and other processes. It is an aliphatic polyester and a crystalline, transparent, easy to process and completely 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, realizing a completely natural cycle. Therefore, PLA is expected to become a raw material for chemical fibers to replace petroleum-based polymer materials, so as to solve the problems of resource shortage and environmental pollution faced by the development of synthetic fibers. However, in practical applications, PLA fibers also expose obvious shortcomings, such as low strength, poor hand feel, and limited antibacterial properties, which limit the application of PLA fibers in certain fields.

Polyhydroxybutyrate-valerate copolyester (PHBV) is a biopolyester produced using starch as raw material and fermentation engineering technology. After its products are discarded, they are stable even in a humid environment, and when microorganisms are present, they will degrade into carbon dioxide and water, without any harm to the environment. However, PHBV has poor melt spinnability and poor fiber mechanical properties. In order to broaden the application of such biodegradable materials in textiles and other fields, PLA and PHBV can be blended and modified to complement each other's advantages. PLA can increase the strength of the material, and PHBV can increase the biodegradation rate and antibacterial properties of the material.

Patent CN102181960A discloses a bio-based degradable fiber containing PHBV and a preparation method thereof. The patent obtains good spinnability at a lower spinning box temperature and a higher spinning speed by vacuum drying PHBV and PLA respectively, then physically mixing them in proportion, melt spinning, and finally post-processing. However, the breaking strength of the final PLA/PHBV fiber can only reach 2.8 cN/dtex at most, which limits its application in the spinning field.

Patent CN105063789A discloses a PHBV/PLA bundled fiber. The fiber prepared in this patent is a blended fiber of PHBV and PLA. The preparation method is: the PHBV and the PLA are mixed and melted, and then extruded through a spinneret, and 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 recorded in this patent is relatively high, it is actually measured to be no more than 2.8 cN/dtex.

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 spun fibers. After 20% PHBV was added to PLA, its breaking strength was only 1.95 cN/dtex.

The fiber used in the master's thesis "Analysis of PHBV/PLA Biomass Fiber Performance and Research on Spinnability [J]., 2018." is a PHBV/PLA blended 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.

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

Summary of the invention

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.

To achieve the above object, the technical solution adopted by the present invention is as follows:

A method for preparing a PLA/PHBV blended fiber, comprising mixing PLA and PHBV and then performing melt spinning to obtain the PLA/PHBV blended fiber;

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.

The present invention solves a technical problem that people have been eager to solve but have never been successful by adjusting process parameters - the breaking strength of PLA/PHBV blended fibers prepared with PLA and PHBV as all raw materials (except these two substances and no other 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 the 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 The decrease in 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 vehicle 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, and the stability of the molecular chains in the fibers will deteriorate, resulting in reduced strength.

As the preferred technical solution:

The preparation method of a PLA/PHBV blended fiber as described above comprises the following specific steps:

(1) Fully dry the PLA slices and PHBV slices respectively;

(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.

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.

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 blowing temperature is 27°C, the annular blowing air inlet pressure is 650 to 750 Pa, and the winding speed is 1050 to 1100 m/min.

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 setting of the six zones is 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 of the six zones of the screw is about 3 to 5 degrees. The temperature setting of the six zones is related to the melting point of the melt and is set in combination with the rheological properties during the processing.

In the method for preparing a PLA/PHBV blended fiber as described above, in step (2), the spinneret holes in the spinneret used for 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 gloss, 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 a good development prospect; fiber profiling can further enhance the antibacterial performance 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.

In the method for preparing a PLA/PHBV blended 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.

The preparation method of a PLA/PHBV blended fiber as described above, the PLA/PHBV blended fiber has a fineness of 2.17-2.32 dtex, a crimp number of 9.1-10.9/25 mm, a crimp rate of 8.4-11.3%, an elongation at break of 39.5-48.9%, an antibacterial rate against Staphylococcus aureus of more than 97%, and an antibacterial rate against Escherichia coli of more than 96.5%.

Beneficial effects:

The invention provides a method for preparing a PLA/PHBV blended fiber with good spinnability, excellent mechanical properties and comprehensive performance.

The PLA/PHBV blended fiber product of the present invention has high quality, good spinnability and mechanical properties, and the breaking strength can reach up to 3.9 cN/dtex, which is 56% higher than the fiber breaking strength of the patent CN102181960A, and the breaking elongation also reaches 48.9%, which greatly improves the spinning application range of PLA fiber; in addition, compared with the spinning process of PLA fiber, PLA/PHBV blended fiber still has good spinnability at a lower spinning box temperature, which can effectively improve production efficiency and reduce costs.

In order to further enhance the mechanical properties and comfort of PLA fibers, the present invention improves the mechanical properties through process adjustment, and at the same time uses fiber profiling to give it improved properties such as gloss, fluffiness, air permeability, elasticity, and hand feel, thereby further improving the wearing performance of PLA fibers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic cross-sectional view of a PLA/PHBV blended fiber prepared when the spinneret hole of the present invention is in the shape of a Chinese character "王";

FIG2 is a schematic cross-sectional view of a PLA/PHBV blended fiber prepared when the spinneret hole of the present invention is cross-shaped;

FIG3 is a schematic cross-sectional view of a PLA/PHBV blended fiber prepared when the spinneret hole of the present invention is trilobal;

FIG4 is a schematic cross-sectional view of a PLA/PHBV blended fiber prepared when the spinneret hole of the present invention is a quad-T-shaped one.

DETAILED DESCRIPTION

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 are not intended 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 fall within the scope limited by the appended claims of the application equally.

The following are some test methods for performance indicators in various embodiments:

Fineness: measured in accordance with GB/T 14336-2008.

Elongation at break: measured in accordance with GB/T 14337-2022.

Breaking strength: measured in accordance with GB/T 14337-2022.

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

Antibacterial rate against Staphylococcus aureus: Determined according to GB/T 20944.3-2008 standard.

Antibacterial rate against Staphylococcus aureus: Determined according to GB/T 20944.3-2008 standard.

Example 1

A method for preparing a PLA/PHBV blended fiber, comprising the following steps:

(1) Preparation of raw materials:

PLA chips: Manufacturer: Total Corbivir Polylactic Acid Company, brand name: L130, intrinsic viscosity: 1.32dL/g;

PHBV slices: the manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., the brand is Y1000P;

(2) drying the PLA slices and PHBV slices at 116°C until the moisture content of each slice is 120 ppm;

(3) mixing the dried PLA slices and PHBV slices, and then sequentially melting and extruding through a screw extruder, spinning, ring-blowing cooling, winding, and forming to obtain raw yarn;

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;

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

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

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

Comparative Example 1

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

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 curl number of 10.8/25mm, a curl rate of 11.6%, an antibacterial rate against Staphylococcus aureus of 93.1%, and an antibacterial rate against Escherichia coli of 91.5%.

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 lead to 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.

Comparative Example 2

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

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 curl number of 9.8/25mm, a curl rate of 10.2%, an antibacterial rate against Staphylococcus aureus of 97.3%, and an antibacterial rate against Escherichia coli of 96.7%.

By comparing Example 1 and Comparative Example 2, it can be seen that in Comparative Example 2, the post-spinning stretching speed is too fast during the melt spinning process, which will lead to a decrease in the fiber breaking strength. This is because the stretching 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.

Comparative Example 3

A method for preparing a PLA/PHBV blended fiber is basically the same as that in Example 1, except that the curling temperature is 80°C.

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 curl number of 11.1/25mm, a curl rate of 12.0%, an antibacterial rate against Staphylococcus aureus of 95.7%, and an antibacterial rate against Escherichia coli of 95.2%.

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 number of curls and the curling rate will increase. This is because the curling temperature is too high, the greater the movement of the molecular chains in the amorphous region of the fiber, and when passing through the winder and after physical extrusion, the greater the deformation of the fiber, which is manifested as an increase in the number of curls and the curling 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.

Example 2

A method for preparing a PLA/PHBV blended fiber, comprising the following steps:

(1) Preparation of raw materials:

PLA chips: Manufacturer: Total Corbivir Polylactic Acid Company, brand name: L130, intrinsic viscosity: 1.31 dL/g;

PHBV slices: the manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., the brand is Y1000P;

(2) drying the PLA slices and PHBV slices at 116°C until the moisture content of each slice is 120 ppm;

(3) mixing the dried PLA slices and PHBV slices, and then sequentially melting and extruding through a screw extruder, spinning, ring-blowing cooling, winding, and forming to obtain raw yarn;

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;

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

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

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

Example 3

A method for preparing a PLA/PHBV blended fiber, comprising the following steps:

(1) Preparation of raw materials:

PLA chips: Manufacturer: Total Corbivir Polylactic Acid Company, brand name: L130, intrinsic viscosity: 1.35 dL/g;

PHBV slices: the manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., the brand is Y1000P;

(2) drying the PLA slices and the PHBV slices at 116°C until the moisture content of each slice is 100 ppm;

(3) mixing the dried PLA slices and PHBV slices, and then sequentially melting and extruding through a screw extruder, spinning, ring-blowing cooling, winding, and forming to obtain raw yarn;

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;

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

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

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 curl number of 9.3/25mm, a curl rate of 8.5%, an antibacterial rate against Staphylococcus aureus of 97.2%, and an antibacterial rate against Escherichia coli of 96.5%.

Example 4

A method for preparing a PLA/PHBV blended fiber, comprising the following steps:

(1) Preparation of raw materials:

PLA chips: Manufacturer: Total Corbivir Polylactic Acid Company, brand name: L130, intrinsic viscosity: 1.34 dL/g;

PHBV slices: the manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., the brand is Y1000P;

(2) drying the PLA slices and the PHBV slices at 116°C until the moisture content of each slice is 100 ppm;

(3) mixing the dried PLA slices and PHBV slices, and then sequentially melting and extruding through a screw extruder, spinning, ring-blowing cooling, winding, and forming to obtain raw yarn;

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;

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

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

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 curl number of 10.9/25 mm, a curl rate of 11.3%, an antibacterial rate against Staphylococcus aureus of 98.2%, and an antibacterial rate against Escherichia coli of 97.9%.

Example 5

A method for preparing a PLA/PHBV blended fiber, comprising the following steps:

(1) Preparation of raw materials:

PLA chips: Manufacturer: Total Corbivir Polylactic Acid Company, brand name: L130, intrinsic viscosity: 1.32dL/g;

PHBV slices: the manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., the brand is Y1000P;

(2) drying the PLA slices and PHBV slices at 116°C until the moisture content of each slice is 160 ppm;

(3) mixing the dried PLA slices and PHBV slices, and then sequentially melting and extruding through a screw extruder, spinning, ring-blowing cooling, winding, and forming to obtain raw yarn;

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;

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

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

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 curl number of 9.8/25mm, a curl rate of 9%, an antibacterial rate against Staphylococcus aureus of 98.3%, and an antibacterial rate against Escherichia coli of 98%.

Example 6

A method for preparing a PLA/PHBV blended fiber, comprising the following steps:

(1) Preparation of raw materials:

PLA chips: Manufacturer: Total Corbivir Polylactic Acid Company, brand name: L130, intrinsic viscosity: 1.33 dL/g;

PHBV slices: the manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., the brand is Y1000P;

(2) drying the PLA slices and the PHBV slices at 116°C until the moisture content of each slice is 110 ppm;

(3) mixing the dried PLA slices and PHBV slices, and then sequentially melting and extruding through a screw extruder, spinning, ring-blowing cooling, winding, and forming to obtain raw yarn;

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;

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

(4) The raw silk is subjected to secondary drawing, curling, and cutting in sequence to obtain PLA/PHBV blended fibers; wherein the post-spinning drawing speed is 115 m/min, the secondary drawing temperature is 63° C., the secondary drawing multiple is 3.18 times, the curling temperature is 65° C., and the mass content of PHBV in the PLA/PHBV blended fibers is 30%.

The final PLA/PHBV blended fiber has a fineness of 2.2dtex, an elongation at break of 40.4%, a breaking strength of 3.7cN/dtex, a curl number of 10.4/25mm, a curl rate of 11.1%, an antibacterial rate against Staphylococcus aureus of 99%, and an antibacterial rate against Escherichia coli of 99.3%.

Example 7

A method for preparing a PLA/PHBV blended fiber, comprising the following steps:

(1) Preparation of raw materials:

PLA chips: Manufacturer: Total Corbivir Polylactic Acid Company, brand name: L130, intrinsic viscosity: 1.32dL/g;

PHBV slices: the manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., the brand is Y1000P;

(2) drying the PLA slices and the PHBV slices at 116°C until the moisture content of each slice is 170 ppm;

(3) mixing the dried PLA slices and PHBV slices, and then sequentially melting and extruding through a screw extruder, spinning, ring-blowing cooling, winding, and forming to obtain raw yarn;

The temperature of the screw extruder zone 1 is 220°C, the temperature of the zone 2 is 222°C, the temperature of the zone 3 is 227°C, the temperature of the zone 4 is 232°C, the temperature of the zone 5 is 227°C, the temperature of the zone 6 is 222°C, the temperature of the spinning box is 225°C, the metering pump supply is 800g/min, the annular air temperature is 27°C, the annular air inlet pressure is 650Pa, and the winding speed is 1050m/min;

The spinneret used in spinning has a spinneret hole shape of a Chinese character "王", with 720 holes;

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

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 curls is 9.8/25 mm, the curl rate is 9.8%, the antibacterial rate against Staphylococcus aureus is 97.4%, and the antibacterial rate against Escherichia coli is 97.7%.

Example 8

A method for preparing a PLA/PHBV blended fiber, comprising the following steps:

(1) Preparation of raw materials:

PLA chips: Manufacturer: Total Corbivir Polylactic Acid Company, brand name: L130, intrinsic viscosity: 1.34 dL/g;

PHBV slices: the manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., the brand is Y1000P;

(2) drying the PLA slices and the PHBV slices at 116°C until the moisture content of each slice is 110 ppm;

(3) mixing the dried PLA slices and PHBV slices, and then sequentially melting and extruding through a screw extruder, spinning, ring-blowing cooling, winding, and forming to obtain raw yarn;

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;

The spinneret used for spinning has a three-lobed shape with 1800 holes;

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

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 curls is 9.7/25 mm, the curl rate is 10.3%, the antibacterial rate against Staphylococcus aureus is 97.7%, and the antibacterial rate against Escherichia coli is 97.3%.

Embodiment 9

A method for preparing a PLA/PHBV blended fiber, comprising the following steps:

(1) Preparation of raw materials:

PLA chips: Manufacturer: Total Corbivir Polylactic Acid Company, brand name: L130, intrinsic viscosity: 1.35 dL/g;

PHBV slices: the manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., the brand is Y1000P;

(2) drying the PLA slices and the PHBV slices at 116°C until the moisture content of each slice is 180 ppm;

(3) mixing the dried PLA slices and PHBV slices, and then sequentially melting and extruding through a screw extruder, spinning, ring-blowing cooling, winding, and forming to obtain raw yarn;

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;

The spinneret used for spinning has a four-T shape with 1200 holes;

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

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 curls is 10.2/25mm, the curl rate is 10.6%, the antibacterial rate against Staphylococcus aureus is 97.5%, and the antibacterial rate against Escherichia coli is 97.6%.

Example 10

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

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 curls is 10.4/25 mm, the curl rate is 9.9%, the antibacterial rate against Staphylococcus aureus is 97.4%, and the antibacterial rate against Escherichia coli is 97.3%.

Embodiment 11

A method for preparing a PLA/PHBV blended fiber, comprising the following steps:

(1) Preparation of raw materials:

PLA chips: Manufacturer: Total Corbivir Polylactic Acid Company, brand name: L130, intrinsic viscosity: 1.33 dL/g;

PHBV slices: the manufacturer is Nanjing Hesu Times Antibacterial Materials Technology Group Co., Ltd., the brand is Y1000P;

(2) drying the PLA slices and PHBV slices at 116°C until the moisture content of each slice is 120 ppm;

(3) mixing the dried PLA slices and PHBV slices, and then sequentially melting and extruding through a screw extruder, spinning, ring-blowing cooling, winding, and forming to obtain raw yarn;

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;

The spinneret holes in the spinneret used for spinning are cross-shaped and W-shaped, with the number of holes in the cross-shaped being 1200 and the number of holes in the W-shaped being 720.

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

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 curl number of 9.6/25mm, a curl rate of 10.4%, an antibacterial rate against Staphylococcus aureus of 97%, and an antibacterial rate against Escherichia coli of 97.1%.

The above is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment, it is not used to limit the present invention. Any technician familiar with this patent can make some changes or modify the technical contents suggested above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the solution of the present invention.

Claims (7)

1. The preparation method of the PLA/PHBV blend fiber is characterized in that PLA and PHBV are mixed and then melt-spun to obtain the PLA/PHBV blend fiber;

PLA has an intrinsic viscosity of 1.31-1.35 dL/g;

the melt spinning comprises a screw extruder melt extrusion process, a circular blowing cooling process, a winding process and a crimping process;

The technological parameters of melt spinning include: the temperature of the spinning box is 223-238 ℃, the pump supply amount of a metering pump is 800-900 g/min, the post-spinning drafting speed is 110-120 m/min, the crimping temperature is 62-67 ℃, the temperature of each zone of the screw extruder is 215-245 ℃, the annular blowing temperature is 27 ℃, the annular blowing air inlet pressure is 650-750 Pa, and the winding speed is 1050-1100 m/min;

the mass content of PHBV in the PLA/PHBV blend fiber is 10-30%;

the fineness of the PLA/PHBV blend fiber is 2.17-2.32 dtex, and the breaking strength is 3.4-3.9 cN/dtex.

2. The method for preparing the PLA/PHBV blend fiber according to claim 1, which is characterized by comprising the following specific steps:

(1) Respectively drying the PLA slice and the PHBV slice;

(2) Mixing the dried PLA slice and PHBV slice, sequentially carrying out melt extrusion, spinning, circular blowing cooling, winding and forming by a screw extruder to obtain a precursor;

(3) And (3) sequentially carrying out secondary drafting, crimping and cutting on the precursor to obtain the PLA/PHBV blend fiber.

3. The method for producing a PLA/PHBV blend fiber according to claim 2, wherein in the step (1), the drying temperature is 116 ℃, and the moisture content of each slice after drying is less than 200ppm.

4. The method according to claim 2, wherein in the step (2), the temperatures of the 1-6 zones of the screw extruder are 220 ℃, 222 ℃, 227 ℃, 232 ℃, 227 ℃, 222 ℃, 220 ℃, 225 ℃, 230 ℃, 235 ℃, 230 ℃, 225 ℃, or 220 ℃, 230 ℃, 235 ℃, 240 ℃, 235 ℃, respectively.

5. The method for producing a PLA/PHBV blend fiber according to claim 2, wherein in the step (2), the spinneret orifices in the spinneret plate used for spinning are one or more of a king-shaped, a cross-shaped, a trilobal, and a tetrat-shaped orifice.

6. The method for preparing PLA/PHBV blend fiber according to claim 2, wherein in the step (3), the temperature of the secondary draft is 62+ -2 ℃, and the multiple of the secondary draft is 3.02-3.35 times.

7. The preparation method of the PLA/PHBV blend fiber according to claim 1, wherein the curl number of the PLA/PHBV blend fiber is 9.1-10.9/25 mm, the curl rate is 8.4-11.3%, the elongation at break is 39.5-48.9%, the antibacterial rate to staphylococcus aureus is more than 97%, and the antibacterial rate to escherichia coli is more than 96.5%.