Method for preparing polyethylene furanoate fiber

Abstract

A method for preparing a polyethylene furanoate fiber, comprising: drying polyethylene furanoate chips and then performing melt-blending spinning, wherein after the drying, the moisture content of the polyethylene furanoate chips is less than or equal to 200 ppm, the crystallinity is 30% to 50%, and the softening temperature is 120-140°C; the melt-blending spinning comprises a screw extruder melt extrusion process, a spinning process, an annular cross-flow cooling process, a two-stage drawing process, and a tension heat setting process; process parameters of the melt-blending spinning comprise: a screw rotation speed of 28-35 r / min, a spinning beam temperature of 265-280°C, an annular cross-flow air supply-return pressure difference of 600-800 Pa, a first-stage drawing temperature of 70-80°C, a second-stage drawing temperature of 100-120°C, a total drawing ratio of 2.94-3.52, and a tension heat setting temperature of 140-160°C. The polyethylene furanoate fiber has excellent mechanical properties.

Description

Process for the preparation of polyethylene furanoate fibers

[0001] This application claims priority to Chinese patent application 2024113756256, filed on September 30, 2024. This application incorporates the entirety of the aforementioned Chinese patent application. TECHNICAL FIELD

[0002] The present application belongs to the technical field of bio-based fiber preparation, and relates to a preparation method of polyethylene furanoate fibers. BACKGROUND

[0003] Bio-based polyester materials are a class of materials with great development potential. Their synthesis raw materials mainly come from renewable biomass resources, such as from crops, plants or other biological sources. These biomass resources are converted into polyester materials through a series of specific chemical processing processes. Unlike traditional fossil-based materials, the production process of bio-based polyester materials reduces the dependence on non-renewable fossil energy. Moreover, after degradation, most of the products of bio-based polyester materials are environmentally friendly substances such as carbon dioxide and water, and the pressure on the environment is relatively small. However, traditional bio-based polyester materials are mainly composed of aliphatic molecular chains. Because the molecular chains are relatively flexible, there is no stable structure such as benzene ring in polyethylene terephthalate (PET), which makes it difficult for the material to have a breaking strength and elongation at break comparable to PET.

[0004] Polyethylene furanoate (PEF) as a new type of bio-based polyester material is the only material with a cyclic structure (rigid furan ring) in bio-based polyesters, which makes its breaking strength and elongation at break superior to traditional bio-based polyester materials. The uniqueness of PEF lies in the replacement of PTA in PET with FDCA in its molecular structure. FDCA, as the main synthetic raw material of PEF, is the only bio-based platform compound with aromatic ring structure, and its raw material mainly comes from carbohydrates such as glucose and fructose. It is a 100% bio-based material and is considered as the most competitive green alternative to PTA. This key substitution not only changes the raw material source of PEF from dependence on limited fossil resources to widely available and renewable carbohydrates (such as glucose, fructose, etc.), but also endows PEF with excellent degradability.

[0005] PEF fiber synthesized by direct esterification or transesterification of FDCA with bio-based diols has great market potential due to its similar structure and performance to PET, especially some better performance, and is hailed as the "next generation polyester". However, in the PEF spinning process, FDCA replaces PTA in PET, resulting in a decrease in molecular chain regularity, which in turn affects the orientation and crystallization performance of the fiber, causing the breaking strength and elongation at break of the fiber to decrease, making it difficult to meet the needs of subsequent processing and application. For example, the literature "Synthesis and Properties of Bio-based Poly(ethylene 2,5-furandicarboxylate) and Its Copolyesters, 2019" explores PEF melt spinning using a single screw extruder and finds that PEF monofilament is brittle and difficult to stretch, with a breaking strength of only 1.15 cN / dtex. For another example, the literature "Synthesis and Fiber Preparation of Spinning Grade Bio-based Poly(ethylene furandicarboxylate) [J]. Journal of Donghua University, 2023, 49(3): 53-60" uses insoluble catalysts and process conditions to synthesize PEF and prepare PEF fibers through a two-step spinning process. The breaking strength of the prepared PEF fibers is only 2.17 cN / dtex at most. For another example, patent application CN106544754B discloses a method for preparing 2,5-furandicarboxylic acid-based polyester fibers, which involves solid-phase tackifying PEF, blending with a de-carboxylation inhibitor and an antioxidant, and then spinning. The breaking strength of the obtained fibers is 4.5-4.7 cN / dtex, but due to the increase in intrinsic viscosity after tackification, the elongation at break of the fibers is only 25-30%.

[0006] To improve the breaking strength and elongation at break of PEF fibers, researchers have attempted to modify PEF by copolymerization, i.e., copolymerizing PTA, FDCA, and diols. However, this has not achieved good results. For example, the literature "Research on Spinnability, Fiber Structure and Properties of Poly(ethylene-2,5-furandicarboxylate) (PEFT) [D], 2018" found that the breaking strength of the fibers after spinning and drawing was only 3.0 cN / dtex. For another example, patent application CN117209735B measures, cools, bundles, hot-draws, and winds the dried cationic dyeable bio-based furandicarboxylic polyester chips after screw extrusion, and the breaking strength of the obtained fibers is only 3.4 cN / dtex at most, with an elongation at break of only 17%. In addition, after copolymerization, the copolymer still contains PTA-provided benzene ring structural units, which have high stability during degradation and can increase the persistence of microplastics in the environment, thereby violating the original intention of bio-based polyester materials.

[0007] Therefore, how to optimize the production process of PEF fiber by copolymerization modification or other technologies to ensure that it has both high breaking strength and elongation at break while maintaining its environmental characteristics under the premise of maintaining the 100% bio-based characteristics of PEF material has become an important research direction in the field of bio-based fiber preparation.

[0008] SUMMARY

[0009] The purpose of the present application is to solve the problems existing in the prior art and provide a preparation method of polyethylene furandicarboxylate fiber.

[0010] To achieve the above-mentioned purpose, the technical scheme adopted by the present application is as follows:

[0011] A preparation method of polyethylene furandicarboxylate fiber, polyethylene furandicarboxylate chips are dried and then melt blended and spun, after drying, the moisture content of the polyethylene furandicarboxylate chips is ≤200ppm, the crystallinity is 30%-50%, and the softening temperature is 120-140℃, if the moisture content of the polyethylene furandicarboxylate chips is higher, it will cause broken yarn and affect the spinning quality, if the softening temperature and crystallinity of the polyethylene furandicarboxylate chips are lower, it may cause ring knot in the screw, causing the spinning to be interrupted;

[0012] The melt blending and spinning includes a screw extruder melt extrusion process, a spinning process, a circular blowing air cooling process, a two-stage drawing process and a tension heat setting process;

[0013] The process parameters of the melt blending and spinning include: screw rotation speed 28-35r / min, spinning box temperature 265-280℃, pressure difference of air inlet and return of circular blowing air 600-800Pa, first-stage drawing temperature 70-80℃, second-stage drawing temperature 100-120℃, total drawing multiple 2.94-3.52 times, and tension heat setting temperature 140-160℃;

[0014] Compared with the prior art, the present application adopts a higher screw rotation speed and a lower spinning box temperature, which can enhance the melt flowability of polyethylene furandicarboxylate, the better the melt flowability, the more stable the yarn output, and the more regular the arrangement of molecular chains, therefore, the orientation and crystallization of the fiber during the drawing and heat setting stages are better, which leads to the improvement of breaking strength and elongation at break;

[0015] The present application also adopts a higher pressure difference of air inlet and return of circular blowing air, which can make the cooling of the fiber more uniform, and after the uniform cooling of the fiber, the molecular chains can be laid into the crystal lattice faster, and the formed crystals are relatively smaller and more perfect, therefore, during the drawing stage, the arrangement of the crystals and amorphous regions (i.e. non-crystalline regions) inside the molecular chains becomes more regular and ordered, and this optimization of the structure directly leads to the significant improvement of the breaking strength and elongation at break of the fiber;

[0016] Meanwhile, under the condition of specific drawing temperature and drawing multiple, all the fibers can reach the state of sufficient drawing, at this time, the breaking strength and breaking elongation of the fibers reach the optimal level; if the drawing is insufficient, the breaking strength of the fibers will be relatively low, and the breaking elongation will be relatively high; on the contrary, if the drawing is excessive, the breaking elongation of the fibers will be significantly reduced;

[0017] In addition, the present application keeps a low tension heat setting temperature, so as to ensure that the stability of fiber forming is high, which in turn helps to improve the overall performance of the fiber; on the contrary, if the stability of fiber forming is low, the fiber is prone to shrinkage in the subsequent processing process, which will lead to the reduction of the breaking strength of the fiber.

[0018] As a preferred technical solution:

[0019] The polyethylene furandicarboxylate fiber is prepared by the method as above, and the intrinsic viscosity of the polyethylene furandicarboxylate chip before drying is 0.65-0.66 dL / g, and the melting point is 215-217 ℃.

[0020] The polyethylene furandicarboxylate fiber is prepared by the method as above, and the drying adopts a combination of programmed temperature rising and programmed vacuumizing, the water molecules on the surface and inside of the chip can be separated by programmed temperature rising and programmed vacuumizing, and in the process of temperature rising, the molecular chain movement is enhanced, the molecular chains in the amorphous region are further crystallized, the crystallinity of the chip is improved, and the less the molecular chains in the amorphous region are, the higher the energy required by the molecular chain movement is in the initial melting stage, and the higher the softening temperature of the chip is.

[0021] The polyethylene furandicarboxylate fiber is prepared by the method as above, and the drying process is as follows: first, drying at 80-100 ℃ for 2-3 h, then heating to 90-120 ℃, vacuumizing to 0.2 MPa and drying for 6-8 h, and finally keeping the temperature unchanged, continuously vacuumizing to 0.05 MPa and drying for 4-6 h.

[0022] The polyethylene furandicarboxylate fiber is prepared by the method as above, and the first-stage drawing adopts oil bath heating, and the first-stage drawing multiple is 2.8-3.2 times; the second-stage drawing adopts steam heating, and the second-stage drawing multiple is 1.05-1.1 times.

[0023] The polyethylene furandicarboxylate fiber is prepared by the method as above, and the process parameters of the melt blending and spinning further include: screw temperature 250-280 ℃, pump supply amount 800-980 g / min, and winding speed 1000-1150 m / min.

[0024] The preparation method of the polyethylen furandicarboxylate fiber as described above, the melt blending spinning further comprises a relaxation heat setting process.

[0025] The preparation method of the polyethylen furandicarboxylate fiber as described above, the overall process flow of the melt blending spinning is: screw extruder melt extrusion→spinning→cooling→winding→forming→bunching→drafting→tension heat setting→crimping→oiling→relaxation heat setting.

[0026] The preparation method of the polyethylen furandicarboxylate fiber as described above, the polyethylen furandicarboxylate fiber has a breaking strength of 3.5-4.5 cN / dtex, an elongation at break of 40.1-55.5%, an ultralong fiber content of 0-3 mg / 100 g, a defect content of 3-20 mg / 100 g, a crimp number of 12-15 per 25 mm, a crimp rate of 14%-18%, a linear density of 2.22-4.44 dtex, and a linear density deviation rate of-5%≤linear density deviation rate≤5%. Advantages:

[0027] (1) The present application significantly improves the mechanical properties (breaking strength and elongation at break) of the polyethylen furandicarboxylate fiber by optimizing the melt blending spinning process parameters, thereby meeting the more extensive application requirements.

[0028] (2) The present application does not introduce any fossil-based raw materials, ensuring the 100% bio-based characteristics of the polyethylen furandicarboxylate fiber, in line with the concept of green and sustainable development.

[0029] (3) The polyethylen furandicarboxylate fiber is completely derived from renewable biomass resources, and its degradation products are mainly carbon dioxide and water, which is environmentally friendly and reduces the risk of microplastic pollution. DETAILED DESCRIPTION

[0030] The present application will be further described in conjunction with the specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. In addition, it should be understood that after reading the content taught by the present application, those skilled in the art can make various modifications or changes to the present application, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

[0031] The test methods of the relevant performance indicators in the following examples and comparative examples are as follows:

[0032] Moisture content: tested in accordance with the GB / T 14189-2015 standard;

[0033] Crystallinity: tested in accordance with the GB / T 19466.3-2004 standard;

[0034] Softening temperature: tested according to GB / T 1633-2000 standard;

[0035] Intrinsic viscosity: tested according to GB / T 14190-2017 standard;

[0036] Melting point: tested according to GB / T 14190-2017 standard;

[0037] Linear density, content of super-long fiber: tested according to GB / T 14335-2008 standard;

[0038] Breaking strength, elongation at break: tested according to GB / T 14337-2022 standard, wherein the tensile speed is 30 mm / min;

[0039] Defect content: tested according to GB / T 14339-2008 standard;

[0040] Number of crimps, crimp rate: tested according to GB / T 14338-2022 standard.

[0041] Example 1

[0042] A preparation method of a polyethylene furanoate fiber, the specific steps are as follows:

[0043] (1) Preparation of raw materials;

[0044] Polyethylene furanoate chips: intrinsic viscosity of 0.65 dL / g, melting point of 215℃;

[0045] (2) The polyethylene furanoate chips are dried, and the drying process is as follows: first dried at 80℃ for 2h, then heated to 116℃, vacuumed to 0.2MPa and dried for 8h, finally kept the temperature unchanged, continued to vacuum to 0.05MPa and dried for 6h;

[0046] The moisture content of the dried polyethylene furanoate chips is 100ppm, the crystallinity is 40.3%, and the softening temperature is 125.2℃;

[0047] (3) The dried polyethylene furanoate chips are sequentially subjected to melt extrusion by a screw extruder, spinning, cooling, winding, molding, bundling, primary drawing (using oil bath heating), secondary drawing (using steam heating), tight heat setting, crimping, oiling, and relaxation heat setting to obtain polyethylene furanoate fibers;

[0048] The relevant process parameters are as follows: the temperature of the first screw zone is 250 DEG C, the temperature of the second screw zone is 255 DEG C, the temperature of the third screw zone is 260 DEG C, the temperature of the fourth screw zone is 265 DEG C, the temperature of the fifth screw zone is 260 DEG C, the temperature of the sixth screw zone is 255 DEG C, the rotating speed of the screw is 31 r / min, the pump supply is 890 g / min, the temperature of the spinning beam is 265 DEG C, the pressure difference between the air inlet and the air return of the air ring is 720 Pa, the winding speed is 1050 m / min, the temperature of the first-stage draft is 72 DEG C, the first-stage draft ratio is 3.1 times, the temperature of the second-stage draft is 110 DEG C, and the second-stage draft ratio is 1.05 times.

[0049] The final polyethylene furandicarboxylate fiber has a linear density of 3.33 dtex, a linear density deviation rate of 0.1%, a breaking strength of 4.5 cN / dtex, a breaking elongation of 48.9%, an ultralong fiber content of 0.5 mg / 100 g, a defect content of 3 mg / 100 g, a number of crimps of 14.5 per 25 mm, and a crimp rate of 16.4%.

[0050] Comparative Example 1

[0051] A method for preparing a fiber is basically the same as in Example 1, except that the drying process is as follows: first drying at 80 DEG C for 2 h, then increasing the temperature to 90 DEG C, vacuumizing to 0.2 MPa, and drying for 4 h, and finally keeping the temperature unchanged, continuously vacuumizing to 0.05 MPa, and drying for 2 h. The moisture content of the dried polyethylene furandicarboxylate chip is 210 ppm, the crystallinity is 38.5%, and the softening temperature is 118 DEG C.

[0052] During the melt blending and spinning process, the fiber frequently appears to be floating and broken. The pressure of the spinning pack is low. The breaking strength of the final fiber is 3.3 cN / dtex, and the breaking elongation is 35.4%.

[0053] Compared with Example 1, the breaking strength and the breaking elongation of the fiber in Comparative Example 1 decrease obviously. This is because the moisture content of the polyethylene furandicarboxylate chip used in the spinning process in Comparative Example 1 is too high, which causes the fiber to break and affects the quality of the spinning.

[0054] Comparative Example 2

[0055] A method for preparing a fiber is basically the same as in Example 1, except that the drying process is as follows: first drying at 80 DEG C for 2 h, then increasing the temperature to 110 DEG C, vacuumizing to 0.2 MPa, and drying for 6 h, and finally keeping the temperature unchanged, continuously vacuumizing to 0.05 MPa, and drying for 4 h. The moisture content of the dried polyethylene furandicarboxylate chip is 100 ppm, the crystallinity is 25%, and the softening temperature is 110 DEG C.

[0056] Due to the too low softening temperature and crystallinity of the polyethylene furanoate chip, the ring knot occurred in the screw during spinning, and the spinning could not continue.

[0057] Comparative Example 3

[0058] A method for preparing a fiber, which is basically the same as Example 1, except that the screw rotation speed is 25 r / min.

[0059] The breaking strength of the finally prepared fiber is 3.5 cN / dtex, and the breaking elongation is 34.7%.

[0060] Comparative Example 4

[0061] A method for preparing a fiber, which is basically the same as Example 1, except that the spinning beam temperature is 285°C.

[0062] The breaking strength of the finally prepared fiber is 3.4 cN / dtex, and the breaking elongation is 32.9%.

[0063] Compared with Comparative Examples 3 and 4 and Example 1, the breaking strength and breaking elongation of the fiber are obviously decreased, because the lower screw rotation speed and the higher spinning beam temperature reduce the melt flowability of the polyethylene furanoate, the melt flowability is poor, the fiber ejection is unstable, and the arrangement of the molecular chains is irregular, so that the orientation and crystallization of the fiber are poor in the drawing and heat setting stages, which results in the decrease of the breaking strength and breaking elongation.

[0064] Comparative Example 5

[0065] A method for preparing a fiber, which is basically the same as Example 1, except that the pressure difference between the inlet air and the return air of the ring blowing is 580 Pa.

[0066] The breaking strength of the finally prepared fiber is 3.2 cN / dtex, and the breaking elongation is 30.7%.

[0067] Compared with Comparative Example 5 and Example 1, the breaking strength and breaking elongation of the fiber are obviously decreased, because the lower pressure difference between the inlet air and the return air of the ring blowing makes the cooling of the fiber not uniform enough, the uneven cooling of the fiber hinders the molecular chains to be laid into the crystal lattice faster, and the formed crystal is relatively large and not perfect enough, so that the arrangement of the crystal and the amorphous region (i.e. non-crystal region) in the molecular chain becomes not regular and ordered enough in the drawing stage, and this structural deterioration directly leads to the obvious decrease of the breaking strength and breaking elongation of the fiber.

[0068] Comparative Example 6

[0069] A method for preparing a fiber, which is basically the same as Example 1, except that the primary drawing multiple is 2.6 times, the secondary drawing multiple is 0.9 times, and the total drawing multiple is 2.34 times.

[0070] The breaking strength of the fiber finally prepared was 3.4 cN / dtex, and the breaking elongation was 57.3%.

[0071] Compared with Example 1, the breaking strength of the fiber of Comparative Example 6 was obviously decreased, and the breaking elongation was obviously increased, which was due to insufficient drawing, resulting in the existence of amorphous region in the fiber, and the elastic of the molecular chain of the amorphous region was relatively large, so that the fiber could be further drawn, causing the increase of the breaking elongation, and the decrease of the crystallinity resulted in the decrease of the breaking strength.

[0072] Comparative Example 7

[0073] A method for preparing a fiber, which was basically the same as Example 1, except that the primary drawing multiple was 3.25, the secondary drawing multiple was 1.1, and the total drawing multiple was 3.58.

[0074] The breaking elongation of the fiber finally prepared was 39.7%.

[0075] Compared with Example 1, the breaking elongation of the fiber of Comparative Example 7 was obviously decreased, which was due to excessive drawing, resulting in the crystallinity in the fiber being too high, and the content of the amorphous molecular chain being less, and the movable molecular chain was less in the drawing process, which resulted in the decrease of the breaking elongation of the fiber.

[0076] Comparative Example 8

[0077] A method for preparing a fiber, which was basically the same as Example 1, except that the tension heat setting temperature was 170°C.

[0078] The breaking strength of the fiber finally prepared was 3.4 cN / dtex.

[0079] Compared with Example 1, the breaking strength of the fiber of Comparative Example 8 was obviously decreased, which was because the higher tension heat setting temperature resulted in the decrease of the stability of the fiber forming, and the fiber was prone to shrinkage in the subsequent processing, thereby resulting in the decrease of the breaking strength of the fiber.

[0080] Example 2

[0081] A method for preparing a poly(ethylene furandicarboxylate) fiber, which was basically the same as Example 1, except that the intrinsic viscosity of the poly(ethylene furandicarboxylate) chip was 0.66 dL / g, and the melting point was 217°C; the water content of the dried poly(ethylene furandicarboxylate) chip was 100 ppm, the crystallinity was 40.8%, and the softening temperature was 125.7°C.

[0082] The final polyethylene furanoate fiber has a linear density of 3.21 dtex, a linear density deviation rate of -0.5%, a breaking strength of 4.3 cN / dtex, an elongation at break of 48.2%, an ultralong fiber content of 0.7 mg / 100 g, a defect content of 3.2 mg / 100 g, a number of crimps of 14.3 per 25 mm, and a crimp rate of 15.7%.

[0083] Example 3

[0084] A method of preparing a polyethylene furanoate fiber, which is substantially the same as that of Example 1, except that the winding speed is 1100 m / min.

[0085] The final polyethylene furanoate fiber has a linear density of 3.26 dtex, a linear density deviation rate of 0.3%, a breaking strength of 4.3 cN / dtex, an elongation at break of 48.3%, an ultralong fiber content of 1 mg / 100 g, a defect content of 3 mg / 100 g, a number of crimps of 13.9 per 25 mm, and a crimp rate of 14.5%.

[0086] Example 4

[0087] A method of preparing a polyethylene furanoate fiber, which is substantially the same as that of Example 1, except that the screw rotation speed is 33 r / min and the pump supply amount is 940 g / min.

[0088] The final polyethylene furanoate fiber has a linear density of 3.84 dtex, a linear density deviation rate of -0.3%, a breaking strength of 4 cN / dtex, an elongation at break of 40.2%, an ultralong fiber content of 1.4 mg / 100 g, a defect content of 4 mg / 100 g, a number of crimps of 12.5 per 25 mm, and a crimp rate of 17.1%.

[0089] Example 5

[0090] A method of preparing a polyethylene furanoate fiber, which is substantially the same as that of Example 1, except that the screw zone 1 temperature is 255°C, the screw zone 2 temperature is 260°C, the screw zone 3 temperature is 265°C, the screw zone 4 temperature is 270°C, the screw zone 5 temperature is 265°C, the screw zone 6 temperature is 260°C, the screw rotation speed is 30 r / min, the spinning beam temperature is 270°C, the winding speed is 1100 m / min, the secondary draw ratio is 1.08 times, and the tension heat setting temperature is 160°C.

[0091] The final polyethylene furanoate fiber has a linear density of 3.17 dtex, a linear density deviation rate of -1%, a breaking strength of 3.9 cN / dtex, an elongation at break of 49.4%, an ultralong fiber content of 0.6 mg / 100 g, a defect content of 3.2 mg / 100 g, a number of crimps of 13.9 per 25 mm, and a crimp rate of 17.3%.

[0092] Example 6

[0093] A method for preparing a polyethylene furanoate fiber, which is substantially the same as that of Example 1, except that the temperature of the first zone of the screw is 260°C, the temperature of the second zone of the screw is 265°C, the temperature of the third zone of the screw is 270°C, the temperature of the fourth zone of the screw is 275°C, the temperature of the fifth zone of the screw is 270°C, the temperature of the sixth zone of the screw is 265°C, the rotation speed of the screw is 29 r / min, the temperature of the spinning beam is 275°C, the winding speed is 1100 m / min, and the first drawing ratio is 3 times.

[0094] The final polyethylene furanoate fiber has a linear density of 3.1 dtex, a linear density deviation rate of 0.8%, a breaking strength of 3.7 cN / dtex, an elongation at break of 50.1%, an ultralong fiber content of 0.6 mg / 100 g, a defect content of 3.2 mg / 100 g, a number of crimps of 14.6 per 25 mm, and a crimp rate of 17.6%.

[0095] Example 7

[0096] A method for preparing a polyethylene furanoate fiber, which is substantially the same as that of Example 2, except that the pressure difference between the inlet air and the return air of the circular blow is 740 Pa.

[0097] The final polyethylene furanoate fiber has a linear density of 3.41 dtex, a linear density deviation rate of 1%, a breaking strength of 4.4 cN / dtex, an elongation at break of 42.6%, an ultralong fiber content of 0 mg / 100 g, a defect content of 3.5 mg / 100 g, a number of crimps of 12.7 per 25 mm, and a crimp rate of 14.3%.

[0098] Example 8

[0099] A method for preparing a polyethylene furanoate fiber, which is substantially the same as that of Example 2, except that the tension heat setting temperature is 155°C.

[0100] The final polyethylene furanoate fiber has a linear density of 3.4 dtex, a linear density deviation rate of 0.7%, a breaking strength of 4.1 cN / dtex, an elongation at break of 41.5%, an ultralong fiber content of 1.2 mg / 100 g, a defect content of 3.5 mg / 100 g, a number of crimps of 12 / 25 mm, and a crimp rate of 14%.

[0101] Example 9

[0102] A method for preparing a polyethylene furanoate fiber, which is substantially the same as that of Example 2, except that the screw rotation speed is 35 r / min and the pump supply amount is 980 g / min.

[0103] The final polyethylene furanoate fiber has a linear density of 3.44 dtex, a linear density deviation rate of 0.5%, a breaking strength of 4 cN / dtex, an elongation at break of 45.2%, an ultralong fiber content of 2 mg / 100 g, a defect content of 4.3 mg / 100 g, a number of crimps of 13.4 / 25 mm, and a crimp rate of 16.8%.

[0104] Example 10

[0105] A method for preparing a polyethylene furanoate fiber, which is substantially the same as that of Example 2, except that the temperature of the first zone of the screw is 265°C, the temperature of the second zone of the screw is 270°C, the temperature of the third zone of the screw is 275°C, the temperature of the fourth zone of the screw is 280°C, the temperature of the fifth zone of the screw is 275°C, the temperature of the sixth zone of the screw is 270°C, the screw rotation speed is 28 r / min, the temperature of the spinning beam is 280°C, the winding speed is 1100 m / min, the first-stage draw ratio is 3.2 times, the second-stage draw ratio is 1.1 times, and the tension heat setting temperature is 155°C.

[0106] The final polyethylene furanoate fiber has a linear density of 2.22 dtex, a linear density deviation rate of 0.7%, a breaking strength of 3.5 cN / dtex, an elongation at break of 55.5%, an ultralong fiber content of 0.4 mg / 100 g, a defect content of 3.3 mg / 100 g, a number of crimps of 15 / 25 mm, and a crimp rate of 18%.

[0107] Example 11

[0108] A method for preparing a polyethylene furanoate fiber, which includes the following steps:

[0109] (1) Preparation of raw materials;

[0110] Polyethylene furanoate chips: intrinsic viscosity of 0.65 dL / g, melting point of 215°C;

[0111] (2) The polyethylene furandicarboxylate chip is dried, and the drying process is as follows: first dried at 100℃ for 2h, then heated to 90℃, vacuumed to 0.2MPa and dried for 6h, and finally kept the temperature unchanged, continuously vacuumed to 0.05MPa and dried for 4h;

[0112] The moisture content of the dried polyethylene furandicarboxylate chip is 200ppm, the crystallinity is 50.0%, and the softening temperature is 120.0℃;

[0113] (3) The dried polyethylene furandicarboxylate chip is sequentially melt-extruded by a screw extruder, spun, cooled, wound, shaped, bundled, first drawn (using oil bath heating), second drawn (using steam heating), tension heat set, crimped, oiled, and relaxed heat set to obtain a polyethylene furandicarboxylate fiber;

[0114] The relevant process parameters are as follows: screw zone 1 temperature 250℃, screw zone 2 temperature 255℃, screw zone 3 temperature 260℃, screw zone 4 temperature 265℃, screw zone 5 temperature 260℃, screw zone 6 temperature 255℃, screw rotation speed 31r / min, pump supply 800g / min, spinning box temperature 265℃, ring blowing air inlet and return air pressure difference 600Pa, winding speed 1000m / min, first drawing temperature 70℃, first drawing multiple 3.1 times, second drawing temperature 100℃, second drawing multiple 1 time, and tension heat setting temperature 160℃.

[0115] The final polyethylene furandicarboxylate fiber has a linear density of 3.22dtex, a linear density deviation rate of -0.3%, a breaking strength of 3.6cN / dtex, a breaking elongation of 46.4%, an ultralong fiber content of 1.5mg / 100g, a defect content of 20mg / 100g, a crimp number of 13.6 / 25mm, and a crimp rate of 14.8%.

[0116] Example 12

[0117] A method for preparing a polyethylene furandicarboxylate fiber, and the specific steps are as follows:

[0118] (1) Preparation of raw materials;

[0119] The polyethylene furandicarboxylate chip has a specific viscosity of 0.66dL / g and a melting point of 217℃;

[0120] (2) The polyethylene furandicarboxylate chip is dried, and the drying process is as follows: first dried at 80℃ for 3h, then heated to 120℃, vacuumed to 0.2MPa and dried for 8h, and finally kept the temperature unchanged, continuously vacuumed to 0.05MPa and dried for 6h;

[0121] The moisture content of the dried polyethylene furanoate chip is 80 ppm, the crystallinity is 30.0%, and the softening temperature is 140.0℃;

[0122] (3) The dried polyethylene furanoate chip is sequentially subjected to melt extrusion by a screw extruder, spinning, cooling, winding, forming, bundling, primary drawing (using oil bath heating), secondary drawing (using steam heating), tight heat setting, crimping, oiling, and relaxation heat setting to obtain a polyethylene furanoate fiber;

[0123] The relevant process parameters are as follows: the temperature of the first zone of the screw is 250℃, the temperature of the second zone of the screw is 255℃, the temperature of the third zone of the screw is 260℃, the temperature of the fourth zone of the screw is 265℃, the temperature of the fifth zone of the screw is 260℃, the temperature of the sixth zone of the screw is 255℃, the rotation speed of the screw is 31 r / min, the pump supply is 890 g / min, the temperature of the spinning box is 265℃, the pressure difference between the inlet and return air of the ring blowing is 800 Pa, the winding speed is 1150 m / min, the primary drawing temperature is 80℃, the primary drawing multiple is 3.1 times, the secondary drawing temperature is 120℃, the secondary drawing multiple is 1.1 times, and the tight heat setting temperature is 155℃.

[0124] The final polyethylene furanoate fiber has a linear density of 2.88 dtex, a linear density deviation rate of 0.5%, a breaking strength of 4 cN / dtex, a breaking elongation of 49.5%, an ultralong fiber content of 3 mg / 100 g, a defect content of 10 mg / 100 g, a crimp number of 14 / 25 mm, and a crimp rate of 17.1%.

[0125] Example 13

[0126] A method for preparing a polyethylene furanoate fiber, the specific steps of which are as follows:

[0127] (1) Preparation of raw materials;

[0128] The polyethylene furanoate chip has a specific viscosity of 0.66 dL / g and a melting point of 217℃;

[0129] (2) The polyethylene furanoate chip is subjected to drying treatment, the drying process of which is as follows: first drying at 80℃ for 2 h, then drying at 116℃ after increasing the temperature and vacuumizing to 0.2 MPa for 8 h, and finally drying at the same temperature after continuously vacuumizing to 0.05 MPa for 6 h;

[0130] The moisture content of the dried polyethylene furanoate chip is 95 ppm, the crystallinity is 40.9%, and the softening temperature is 125.8℃;

[0131] (3) the dried polyethylene furanoate chip is sequentially subjected to melt extrusion by a screw extruder, spinning, cooling, winding, forming, bundling, primary drawing (using oil bath heating), secondary drawing (using steam heating), tight heat setting, crimping, oiling, and relaxation heat setting to obtain the polyethylene furanoate fiber;

[0132] The relevant process parameters are as follows: the temperature of the first zone of the screw is 250°C, the temperature of the second zone of the screw is 255°C, the temperature of the third zone of the screw is 260°C, the temperature of the fourth zone of the screw is 265°C, the temperature of the fifth zone of the screw is 260°C, the temperature of the sixth zone of the screw is 255°C, the rotation speed of the screw is 31 r / min, the pump supply is 890 g / min, the temperature of the spinning beam is 265°C, the pressure difference between the inlet air and the return air of the ring blowing is 720 Pa, the winding speed is 1100 m / min, the temperature of the primary drawing is 72°C, the primary drawing multiple is 2.8 times, the temperature of the secondary drawing is 100°C, and the secondary drawing multiple is 1.05 times.

[0133] The final polyethylene furanoate fiber has a linear density of 4.44 dtex, a linear density deviation rate of -5%, a breaking strength of 3.8 cN / dtex, a breaking elongation of 41.4%, an ultralong fiber content of 1.6 mg / 100 g, a defect content of 6 mg / 100 g, a crimp number of 14.1 per 25 mm, and a crimp rate of 16.8%.

[0134] Example 14

[0135] A method for preparing a polyethylene furanoate fiber, and the specific steps are as follows:

[0136] (1) preparation of raw materials;

[0137] The polyethylene furanoate chip has a specific viscosity of 0.66 dL / g and a melting point of 217°C.

[0138] (2) The polyethylene furanoate chip is subjected to drying treatment, and the drying process is as follows: first, drying at 80°C for 2 h, then increasing the temperature to 116°C, vacuumizing to 0.2 MPa, and drying for 8 h, and finally keeping the temperature unchanged, continuously vacuumizing to 0.05 MPa, and drying for 6 h.

[0139] The water content of the dried polyethylene furanoate chip is 95 ppm, the crystallinity is 40.8%, and the softening temperature is 125.7°C.

[0140] (3) the dried polyethylene furanoate chip is sequentially subjected to melt extrusion by a screw extruder, spinning, cooling, winding, forming, bundling, primary drawing (using oil bath heating), secondary drawing (using steam heating), tight heat setting, crimping, oiling, and relaxation heat setting to obtain the polyethylene furanoate fiber;

[0141] The relevant process parameters are as follows: the temperature of the first zone of the screw is 250 DEG C, the temperature of the second zone of the screw is 255 DEG C, the temperature of the third zone of the screw is 260 DEG C, the temperature of the fourth zone of the screw is 265 DEG C, the temperature of the fifth zone of the screw is 260 DEG C, the temperature of the sixth zone of the screw is 255 DEG C, the rotating speed of the screw is 31 r / min, the pump supply is 890 g / min, the temperature of the spinning beam is 265 DEG C, the pressure difference between the air inlet and the return air of the ring blowing is 720 Pa, the winding speed is 1100 m / min, the temperature of the first-stage draft is 72 DEG C, the first-stage draft multiple is 2.9, the temperature of the second-stage draft is 110 DEG C, the second-stage draft multiple is 1.08, and the tension heat setting temperature is 145 DEG C.

[0142] The final polyfuran dicarboxylic acid glycol ester fiber has a linear density of 3.98 dtex, a linear density deviation rate of 5%, a breaking strength of 3.5 cN / dtex, a breaking elongation of 40.1%, an ultralong fiber content of 0.8 mg / 100 g, a defect content of 7 mg / 100 g, a number of crimps of 12.9 per 25 mm, and a crimp rate of 17.3%.

Claims

1. A method for producing polyethylenefuranoate fiber, which dries polyethylenefuranoate chips and then performs melt blending and spinning, characterized by, After drying, the moisture content of the poly(ethylene furandicarboxylate) chip is less than or equal to 200 ppm, the crystallinity is 30%-50%, and the softening temperature is 120-140 DEG C; The melt blending spinning comprises a screw extruder melt extrusion process, a spinning process, a circular air blowing cooling process, a two-stage drawing process, and a tension heat setting process. The process parameters of the melt blending spinning comprise a screw rotation speed of 28-35 r / min, a spinning box temperature of 265-280 DEG C, a pressure difference between the air inlet and the air return of the circular air blowing of 600-800 Pa, a first-stage drawing temperature of 70-80 DEG C, a second-stage drawing temperature of 100-120 DEG C, a total drawing multiple of 2.94-3.52 times, and a tension heat setting temperature of 140-160 DEG C.

2. The method for preparing poly(ethylene furanate) fiber according to claim 1, characterized in that, Before drying, the poly(ethylene furandicarboxylate) chip has an intrinsic viscosity of 0.65-0.66 dL / g and a melting point of 215-217 DEG C.

3. The method for preparing poly(ethylene furanate) fiber according to claim 1, characterized in that, The drying is performed by combining a programmed temperature increase with a programmed vacuum extraction.

4. The method for preparing poly(ethylene furanate) fiber according to claim 3, characterized in that, The drying process comprises first drying at 80-100 DEG C for 2-3 h, then drying at 90-120 DEG C after increasing the temperature and extracting the vacuum to 0.2 MPa for 6-8 h, and finally drying at the same temperature after continuing to extract the vacuum to 0.05 MPa for 4-6 h.

5. The method for preparing poly(ethylene furanate) fiber according to claim 1, characterized in that, The first-stage drawing is performed by oil bath heating, and the first-stage drawing multiple is 2.8-3.2 times; the second-stage drawing is performed by steam heating, and the second-stage drawing multiple is 1.05-1.1 times.

6. The method for preparing poly(ethylene furanate) fiber according to claim 5, characterized in that, The process parameters of the melt blending spinning further comprise a screw temperature of 250-280 DEG C, a pump supply of 800-980 g / min, and a winding speed of 1000-1150 m / min.

7. The method for preparing poly(ethylene furanate) fiber according to claim 1, characterized in that, The melt blending spinning further comprises a relaxation heat setting process.

8. The method for preparing poly(ethylene furanate) fiber according to claim 7, characterized in that, The overall process flow of the melt blending spinning is: screw extruder melt extrusion -> spinning -> cooling -> winding -> forming -> bundling -> drawing -> tension heat setting -> crimping -> oiling -> relaxation heat setting.

9. A process for the production of polyethylenefurandicarboxylate fibers according to any one of claims 1 to 8, characterized in that, The poly(ethylene furandicarboxylate) fiber has a breaking strength of 3.5-4.5 cN / dtex, an elongation at break of 40.1-55.5%, an ultralong fiber content of 0-3 mg / 100 g, a defect content of 3-20 mg / 100 g, a crimp number of 12-15 per 25 mm, a crimp rate of 14%-18%, a linear density of 2.22-4.44 dtex, and a linear density deviation rate of -5% to 5%.