High-shrinkage polyamide fiber, process for its production and use

Abstract

The present application relates to a kind of high shrinkage polyamide fibers, its preparation method and application.The high shrinkage polyamide fiber is the blend fiber of polyamide 6 / polyamide 56;Wherein, the high shrinkage polyamide fiber boiling water shrinkage is 30~60%, and 20~80wt% polyamide 56 is contained in the high shrinkage polyamide fiber, 80~20wt% polyamide 6.The high shrinkage polyamide fiber of the present application not only uses the material of biobased source as main raw material, green environmental protection, and the polyamide 56 / polyamide 6 blend fiber has high shrinkage performance, soft and the like characteristics, is suitable for high shrinkage fabric, quality is extremely high, so it can be applied in high-grade clothing purposes etc..

Description

Technical Field

[0001] This invention belongs to the field of polyamide material technology, and relates to a high-shrinkage polyamide fiber, its preparation method and application. Background Technology

[0002] High-shrinkage fiber (HSF) is a type of fiber produced through physical (mainly blending or compounding) or chemical (mainly copolymerization) modification. It generally refers to chemical fibers with a boiling water shrinkage rate or dry heat shrinkage rate exceeding 25%. A key characteristic of HSF is its shrinkage rate of 25%–70% during heat treatment, allowing for the production of various fabrics with unique styles. When HSF is interwoven, coated, or blended with other fibers, the resulting fabrics have a full, smooth hand feel, excellent drape, and a tight structure. In recent years, with the development and utilization of composite microfibers and new synthetic fibers, the applications and usage of HSF have become increasingly widespread. In particular, interweaving it with composite microfibers can produce high-grade imitation suede fabrics, imitation peach skin fabrics, high-density fabrics, and imitation silk fabrics.

[0003] Patent CN105887218 A discloses a high-shrinkage nylon fiber and its preparation method, using copolymerized light-cut nylon 6 and nylon 66 as raw materials, with nylon 6 accounting for 50-80% and nylon 66 accounting for 20-50%. The raw materials are fed into a screw extruder for melting and mixing under nitrogen protection, and then spun on a spinning machine. The boiling water shrinkage rate is 27-30%, indicating that the boiling water shrinkage rate of this high-shrinkage nylon fiber is relatively low. Patent CN101646812 B discloses a high-shrinkage fiber composed of nylon MXD6 polymer and nylon 6 polymer, with a weight ratio of 35:65-70:30. The tensile strength is above 4.0 cN / dtex. MXD6 is a semi-aromatic polyamide, which is difficult to spin and has high production consumption.

[0004] Patent CN 106676673 A discloses a nylon high-shrinkage fiber, which includes a first high-shrinkage component and a second high-shrinkage component. The first high-shrinkage component includes a nylon 6 component and an antistatic component, and the second high-shrinkage component includes a nylon 66 component and an antistatic component. The first high-shrinkage component and the second high-shrinkage component are melt-extruded through a twin-screw extruder to produce a core-sheath type high-shrinkage fiber. The high-shrinkage fiber adopts composite spinning technology, which requires a large investment in equipment, has high production costs, and is complex to operate.

[0005] Patent CN 104018246 A discloses a method for preparing polyester-nylon composite microfiber with high shrinkage rate. High-shrinkage polyester chips are dried and then melted in a first screw extruder to obtain a first spinning melt. Nylon 6 chips are dried and then melted in a second screw extruder to obtain a second spinning melt. The first and second spinning melts are then combined and spun to produce POY. DTY is then produced using a texturing machine. The boiling water shrinkage rate of the fiber is above 15%. This high-shrinkage fiber also employs composite spinning technology, resulting in significant equipment investment, high production costs, and complex operation.

[0006] Japanese Patent Application Publication No. 8-209444 discloses a nylon fiber with high shrinkage performance and a boiling water shrinkage rate of over 30%. This nylon is mainly obtained through copolymerization, but the copolymerization modification process is complicated and the production cost is high.

[0007] It is evident that the existing polyamide fibers still have many defects and urgently need further improvement. Summary of the Invention

[0008] The first objective of this invention is to provide a high-shrinkage polyamide fiber.

[0009] The second objective of this invention is to provide a method for preparing the above-mentioned high-shrinkage polyamide fiber.

[0010] A third objective of this invention is to provide an application of the aforementioned high-shrinkage polyamide fiber.

[0011] To achieve the above objectives, the solution of the present invention is:

[0012] [High-shrinkage polyamide fiber]

[0013] In one aspect, the present invention provides a high-shrinkage polyamide fiber, wherein the high-shrinkage polyamide fiber is a blend of polyamide 6 and polyamide 56;

[0014] The high-shrinkage polyamide fiber has a boiling water shrinkage rate of 30-60%.

[0015] The high-shrinkage polyamide fiber contains 20-80 wt% polyamide 56 and 80-20 wt% polyamide 6.

[0016] In a preferred embodiment of the present invention, the weight ratio of polyamide 56 to polyamide 6 in the high-shrinkage polyamide fiber is 25:75 to 75:25; more preferably, it is 35:65 to 70:30; more preferably, it is 40:60 to 65:35; particularly preferably, it is 45:55 to 60:40. For example, the weight ratio of polyamide 56 to polyamide 6 is 28:72, 32:68, 42:58, or 76:24.

[0017] One of the raw materials for polyamide 56, 1,5-pentanediamine, is prepared from bio-based raw materials through fermentation or enzymatic conversion.

[0018] Depending on the specific circumstances, the high-shrinkage polyamide fiber may also contain additives. These additives may include any one or more of the following: matting agents, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers, nucleating agents, fluorescent whitening agents, or antistatic agents. The amount of these additives may be 0.001-10% of the total weight of the raw materials.

[0019] In a preferred embodiment of the present invention, the boiling water shrinkage rate of the high-shrinkage polyamide fiber is 30-57%, preferably 30-55%, more preferably 32-53%, and even more preferably 32-48%.

[0020] In a preferred embodiment of the present invention, the breaking strength of the high-shrinkage polyamide fiber is 2.5 to 10.0 cN / dtex, preferably 3.0 to 8.5 cN / dtex, more preferably 3.5 to 6.0 cN / dtex, and even more preferably 4.0 to 5.7 cN / dtex.

[0021] In a preferred embodiment of the present invention, the high-shrinkage polyamide fiber has an elastic recovery rate of 96% or more under 10% stretching conditions, preferably 96-100%; and / or, the high-shrinkage polyamide fiber has an elastic recovery rate of 85.5% or more under 20% stretching conditions, more preferably 86-90%.

[0022] In a preferred embodiment of the present invention, the fineness of the high-shrinkage polyamide fiber is 1.0 to 3000 dtex, preferably 3 to 1000 dtex, more preferably 5 to 500 dtex, even more preferably 10 to 300 dtex, and even more preferably 10 to 150 dtex.

[0023] In a preferred embodiment of the present invention, the modulus of the high-shrinkage polyamide fiber is 20-45 cN / dtex, preferably 25-40 cN / dtex, and more preferably 30-40 cN / dtex.

[0024] The cross-sectional shape of the high-shrinkage polyamide fiber is any one of the following: circular, trilobal, cross-shaped, triangular, hollow triangular, I-shaped, T-shaped, Y-shaped, flat, pentagonal, hexagonal, octagonal, I-shaped, or dumbbell-shaped.

[0025] The aforementioned high-shrinkage polyamide fibers include civilian filaments, industrial filaments, bulked textured yarns, monofilaments, and staple fibers.

[0026] [Preparation method of high-shrinkage polyamide fiber]

[0027] In another aspect, the present invention also provides a method for preparing the above-mentioned high-shrinkage polyamide fiber, the method comprising the following steps:

[0028] (1) Mix polyamide 56 and polyamide 6 resin raw materials evenly in a certain proportion, and then dry them;

[0029] (2) Heat the polyamide blend obtained from step (1) to a molten state to form a polyamide melt, and extrude it to form a nascent filament;

[0030] (3) The nascent filament is subjected to stretching and heat setting treatment to obtain the high-shrinkage polyamide fiber.

[0031] In step (1), the mixing is performed in a mixing silo; and / or,

[0032] The drying is carried out in a vacuum drum dryer or a continuous nitrogen-filled dryer; and / or,

[0033] The relative viscosity of the polyamide 56 resin raw material is 2.4–3.5, preferably 2.5–3.3, more preferably 2.6–3.2, and even more preferably 2.7–3.1; and / or,

[0034] The relative viscosity of the polyamide 6 resin raw material is 2.2–3.5, preferably 2.3–3.3, more preferably 2.4–3.0, and even more preferably 2.5–2.8; and / or,

[0035] The drying temperature is 60–120°C, and the drying time is 8–30 hours; and / or,

[0036] The moisture content of the dried blended polyamide resin is ≤1000ppm, preferably 200-900ppm, more preferably 300-800ppm, and even more preferably 400-600ppm.

[0037] In step (2),

[0038] The extrusion is performed through a spinneret; and / or,

[0039] The heating is carried out in a screw extruder, which is divided into five heating zones;

[0040] In this zone, the temperature is 220–250℃; and / or,

[0041] The temperature in Zone II is 240–300℃; and / or,

[0042] The temperature in Zone 3 is 250–320℃; and / or,

[0043] The temperature in Zone 4 is 260–310℃; and / or,

[0044] The temperature in zone five is 270–300℃; and / or,

[0045] The temperature in zone two is greater than the temperature in zone one; and / or,

[0046] The temperatures in Zone 3, Zone 4, and / or Zone 5 are greater than the temperatures in Zone 1 and / or Zone 2.

[0047] The spinning process in step (2) includes the following steps:

[0048] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament;

[0049] The temperature of the spinning box is 270–310°C, preferably 275–300°C, more preferably 280–295°C, and even more preferably 285–290°C; and / or,

[0050] The spinning assembly pressure of the spinning box is 10-25 MPa, preferably 13-20 MPa, and more preferably 16-18 MPa.

[0051] In step (3), the stretching and heat setting process is performed on two pairs of hot rollers. The stretching ratio of the stretching and heat setting is 1 to 2.8 times, preferably 1.2 to 1.8 times, more preferably 1.3 to 1.6 times, and even more preferably 1.4 to 1.6 times; and / or,

[0052] The heat setting temperature is 60–150°C, more preferably 65–95°C, even more preferably 70–93°C, and even more preferably 80–90°C.

[0053] Applications of high-shrinkage polyamide fibers

[0054] In another aspect, the present invention also provides the application of the above-mentioned high-shrinkage polyamide fibers in the preparation of high-grade imitation suede fabrics, imitation peach skin fabrics, high-density fabrics, imitation silk fabrics and / or hetero-shrinkage blended fiber fabrics.

[0055] Due to the adoption of the above solution, the beneficial effects of the present invention are:

[0056] First, the polyamide 56 resin selected in this invention is made by a biological method, making it a green material that does not rely on petroleum resources, does not cause serious pollution to the environment, and can reduce carbon emissions and reduce the greenhouse effect.

[0057] Secondly, the high-shrinkage polyamide fiber of the present invention, in addition to having the strength of general polyamide fibers, also has high shrinkage performance. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0059] The method for detecting the performance parameters involved in this invention is as follows:

[0060] 1) Relative viscosity:

[0061] Ubbelohde viscometer method with concentrated sulfuric acid: Accurately weigh 0.25±0.0002g of dried polyamide 56 chips or short fiber samples, add 50mL of concentrated sulfuric acid (96%) to dissolve, and measure and record the flow time t0 of concentrated sulfuric acid and the flow time t of polyamide sample solution in a 25℃ constant temperature water bath.

[0062] Viscosity calculation formula: Relative viscosity = t / t0

[0063] t — time it takes for the solution to flow through;

[0064] t0 — Solvent flow time.

[0065] 2) Fracture strength:

[0066] The breaking strength can be determined by referring to GB / T 14344-2008 Test Method for Tensile Properties of Chemical Fiber Filaments; apply a pretension of 0.05±0.005cN / dtex, a holding distance of 500mm, and a tensile speed of 500mm / min.

[0067] Modulus = breaking strength at 1% elongation at break × 100.

[0068] 3) Boiling water shrinkage rate:

[0069] The determination of boiling water shrinkage rate refers to GB / T 6505-2008 "Test method for heat shrinkage rate of chemical fiber filaments". Specifically, take a section of high-shrinkage polyamide fiber, pre-tension 0.05±0.005cN / dtex, mark 50.00cm at both ends in the middle, wrap it with gauze, put it into boiling water and boil for 30min. Then, after drying the sample, measure the change in length before and after boiling.

[0070] 4) Elastic recovery rate:

[0071] The electronic single yarn tensile strength tester YG061 was used, with parameters set according to the test method in GB / T 14344-2003. The ambient temperature was 23℃ and the humidity was 65%. The tensile interval was 500mm, the pre-tension was 0.1cN / dtex, and the tensile speed was 500mm / min. The yarn was stretched to the set elongation (E=10% and 20%), and then the instrument was stopped and relaxed for 60s before being restored. The test was repeated 10 times.

[0072] Elastic recovery rate = ((L-L1) / (L-L0))*100%

[0073] Where L0 is the original length of the sample, L is the length of the sample after being stretched to a certain elongation, and L1 is the length of the sample after being reset.

[0074] Example 1

[0075] (1) Mix polyamide 56 resin and polyamide 6 resin evenly in a mixing bin at a ratio of 80:20 (mass ratio), and then dry them in a vacuum drum dryer at a drying temperature of 80℃ for 20h.

[0076] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0077] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0078] Step (1) The relative viscosity of polyamide 56 resin is 2.7, the relative viscosity of polyamide 6 resin is 2.4, and the water content of the blended polyamide resin after drying is 400 ppm.

[0079] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 230°C; the temperature of zone two is 250°C; the temperature of zone three is 270°C; the temperature of zone four is 280°C; and the temperature of zone five is 290°C.

[0080] The spinning process in step (2) includes the following steps:

[0081] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 285°C and the pressure of the spinning assembly is 12.5 MPa.

[0082] In step (3), the stretching and heat setting are completed on two pairs of hot rollers. The stretching ratio of the nascent filament is 1.3 times, and the heat setting temperature is 85°C.

[0083] The performance of the obtained products is listed in Tables 1 and 2.

[0084] Example 2

[0085] (1) Mix polyamide 56 resin and polyamide 6 resin evenly in a mixing bin at a ratio of 70:30 (mass ratio), and then dry them in a vacuum drum dryer at a drying temperature of 95°C for 15 hours.

[0086] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0087] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0088] Step (1) The relative viscosity of polyamide 56 resin is 2.8, the relative viscosity of polyamide 6 resin is 2.7, and the water content of the blended polyamide resin after drying is 600 ppm.

[0089] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 240°C; the temperature of zone two is 260°C; the temperature of zone three is 270°C; the temperature of zone four is 280°C; and the temperature of zone five is 290°C.

[0090] The spinning process in step (2) includes the following steps:

[0091] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 290°C and the pressure of the spinning assembly is 17.0 MPa.

[0092] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.5 times and a heat setting temperature of 95°C.

[0093] The performance of the obtained products is listed in Tables 1 and 2.

[0094] Example 3

[0095] (1) Mix polyamide 56 resin and polyamide 6 resin evenly in a mixing bin at a ratio of 60:40 (mass ratio), and then dry them in a vacuum drum dryer at a drying temperature of 110℃ for 13 hours.

[0096] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0097] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0098] Step (1) The relative viscosity of polyamide 56 resin is 2.6, the relative viscosity of polyamide 6 resin is 2.5, and the water content of the blended polyamide resin after drying is 500ppm.

[0099] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 235°C; the temperature of zone two is 245°C; the temperature of zone three is 265°C; the temperature of zone four is 275°C; and the temperature of zone five is 285°C.

[0100] The spinning process in step (2) includes the following steps:

[0101] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 280°C and the pressure of the spinning assembly is 20.0 MPa.

[0102] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.7 times and a heat setting temperature of 98°C.

[0103] The performance of the obtained products is listed in Tables 1 and 2.

[0104] Example 4

[0105] (1) Mix polyamide 56 resin and polyamide 6 resin in a mixing bin at a ratio of 50:50 (mass ratio), and then dry them in a vacuum drum dryer at a temperature of 90°C for 18 hours.

[0106] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0107] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0108] Step (1) The relative viscosity of polyamide 56 resin is 3.0, the relative viscosity of polyamide 6 resin is 2.8, and the water content of the blended polyamide resin after drying is 500ppm.

[0109] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 245°C; the temperature of zone two is 270°C; the temperature of zone three is 290°C; the temperature of zone four is 305°C; and the temperature of zone five is 300°C.

[0110] The spinning process in step (2) includes the following steps:

[0111] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 295°C and the pressure of the spinning assembly is 18.5 MPa.

[0112] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.4 times and a heat setting temperature of 88°C.

[0113] The performance of the obtained products is listed in Tables 1 and 2.

[0114] Example 5

[0115] (1) Mix polyamide 56 resin and polyamide 6 resin evenly in a mixing bin at a ratio of 35:65 (mass ratio), and then dry them in a vacuum drum dryer at a drying temperature of 120℃ for 10 hours.

[0116] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0117] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0118] Step (1) The relative viscosity of polyamide 56 resin is 2.7, the relative viscosity of polyamide 6 resin is 2.7, and the water content of the blended polyamide resin after drying is 700ppm.

[0119] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 220°C; the temperature of zone two is 240°C; the temperature of zone three is 260°C; the temperature of zone four is 270°C; and the temperature of zone five is 280°C.

[0120] The spinning process in step (2) includes the following steps:

[0121] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 275°C and the pressure of the spinning assembly is 12.5 MPa.

[0122] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.6 times and a heat setting temperature of 80°C.

[0123] The performance of the obtained products is listed in Tables 1 and 2.

[0124] Example 6

[0125] (1) Mix polyamide 56 resin and polyamide 6 resin in a mixing bin at a ratio of 30:70 (mass ratio), and then dry them in a vacuum drum dryer at a temperature of 80°C for 20 hours.

[0126] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0127] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0128] Step (1) The relative viscosity of polyamide 56 resin is 3.2, the relative viscosity of polyamide 6 resin is 3.0, and the water content of the blended polyamide resin after drying is 800ppm.

[0129] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 250°C; the temperature of zone two is 280°C; the temperature of zone three is 310°C; the temperature of zone four is 305°C; and the temperature of zone five is 300°C.

[0130] The spinning process in step (2) includes the following steps:

[0131] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 300°C and the pressure of the spinning assembly is 16.0 MPa.

[0132] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.2 times and a heat setting temperature of 90°C.

[0133] The performance of the obtained products is listed in Tables 1 and 2.

[0134] Example 7

[0135] (1) Mix polyamide 56 resin and polyamide 6 resin in a mixing bin at a ratio of 30:70 (mass ratio), and then dry them in a vacuum drum dryer at a temperature of 80°C for 14 hours.

[0136] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0137] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0138] Step (1) The relative viscosity of polyamide 56 resin is 2.7, the relative viscosity of polyamide 6 resin is 2.8, and the water content of the blended polyamide resin after drying is 280ppm.

[0139] The heating in step (2) is carried out in a screw extruder, which is preferably divided into five heating zones; wherein, the temperature of zone one is 245°C; the temperature of zone two is 270°C; the temperature of zone three is 295°C; the temperature of zone four is 305°C; and the temperature of zone five is 298°C.

[0140] The spinning process in step (2) includes the following steps:

[0141] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 280°C and the pressure of the spinning assembly is 11.0 MPa.

[0142] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 2.8 times and a heat setting temperature of 150°C.

[0143] The performance of the obtained products is listed in Tables 1 and 2.

[0144] Example 8

[0145] (1) Mix polyamide 56 resin and polyamide 6 resin in a mixing bin at a ratio of 20:80 (mass ratio), and then dry them in a vacuum drum dryer at a temperature of 70°C for 25 hours.

[0146] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0147] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0148] Step (1) The relative viscosity of polyamide 56 resin is 2.5, the relative viscosity of polyamide 6 resin is 2.5, and the water content of the blended polyamide resin after drying is 900 ppm.

[0149] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 230°C; the temperature of zone two is 250°C; the temperature of zone three is 270°C; the temperature of zone four is 280°C; and the temperature of zone five is 275°C.

[0150] The spinning process in step (2) includes the following steps:

[0151] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 270°C and the pressure of the spinning assembly is 14.0 MPa.

[0152] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.3 times and a heat setting temperature of 75°C.

[0153] The performance of the obtained products is listed in Tables 1 and 2.

[0154] Comparative Example 1

[0155] (1) Mix polyamide 56 resin and polyamide 6 resin evenly in a mixing bin at a ratio of 85:15 (mass ratio), and then dry them in a vacuum drum dryer at a drying temperature of 80℃ for 20h.

[0156] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0157] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0158] Step (1) The relative viscosity of polyamide 56 resin is 2.7, the relative viscosity of polyamide 6 resin is 2.4, and the water content of the blended polyamide resin after drying is 400ppm.

[0159] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 230°C; the temperature of zone two is 250°C; the temperature of zone three is 270°C; the temperature of zone four is 280°C; and the temperature of zone five is 290°C.

[0160] The spinning process in step (2) includes the following steps:

[0161] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 285°C and the pressure of the spinning assembly is 12.5 MPa.

[0162] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.3 times and a heat setting temperature of 85°C.

[0163] The performance of the obtained products is listed in Tables 1 and 2.

[0164] Comparative Example 2

[0165] (1) Mix polyamide 56 resin and polyamide 6 resin in a mixing bin at a ratio of 10:90 (mass ratio), and then dry them in a vacuum drum dryer at a temperature of 95°C for 15 hours.

[0166] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0167] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0168] Step (1) The relative viscosity of polyamide 56 resin is 2.8, the relative viscosity of polyamide 6 resin is 2.7, and the water content of the blended polyamide resin after drying is 600 ppm.

[0169] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 240°C; the temperature of zone two is 260°C; the temperature of zone three is 270°C; the temperature of zone four is 280°C; and the temperature of zone five is 290°C.

[0170] The spinning process in step (2) includes the following steps:

[0171] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 290°C and the pressure of the spinning assembly is 17.0 MPa.

[0172] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.5 times and a heat setting temperature of 95°C.

[0173] The performance of the obtained products is listed in Tables 1 and 2.

[0174] Comparative Example 3

[0175] (1) Mix polyamide 56 resin and polyamide 66 resin evenly in a mixing hopper at a ratio of 70:30 (mass ratio), and then dry them in a vacuum drum dryer at a drying temperature of 95°C for 16 hours.

[0176] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0177] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0178] Step (1) The relative viscosity of polyamide 56 resin is 2.8, the relative viscosity of polyamide 66 resin is 2.7, and the water content of the blended polyamide resin after drying is 600ppm.

[0179] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 240°C; the temperature of zone two is 260°C; the temperature of zone three is 270°C; the temperature of zone four is 280°C; and the temperature of zone five is 290°C.

[0180] The spinning process in step (2) includes the following steps:

[0181] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 290°C and the pressure of the spinning assembly is 17.0 MPa.

[0182] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.5 times and a heat setting temperature of 95°C.

[0183] The performance of the obtained products is listed in Tables 1 and 2.

[0184] Comparative Example 4

[0185] (1) Mix polyamide 56 resin and polyamide 66 resin evenly in a mixing bin at a ratio of 50:50 (mass ratio), and then dry them in a vacuum drum dryer at a temperature of 90°C for 18 hours.

[0186] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0187] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0188] Step (1) The relative viscosity of polyamide 56 resin is 3.0, the relative viscosity of polyamide 66 resin is 2.8, and the water content of the blended polyamide resin after drying is 500ppm.

[0189] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 245°C; the temperature of zone two is 270°C; the temperature of zone three is 290°C; the temperature of zone four is 305°C; and the temperature of zone five is 300°C.

[0190] The spinning process in step (2) includes the following steps:

[0191] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 295°C and the pressure of the spinning assembly is 18.3 MPa.

[0192] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.4 times and a heat setting temperature of 88°C.

[0193] The performance of the obtained products is listed in Tables 1 and 2.

[0194] Comparative Example 5

[0195] (1) Mix polyamide 56 resin and polyamide 66 resin evenly in a mixing bin at a ratio of 35:65 (mass ratio), and then dry them in a vacuum drum dryer at a drying temperature of 120℃ for 11 hours.

[0196] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0197] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0198] Step (1) The relative viscosity of polyamide 56 resin is 2.7, the relative viscosity of polyamide 66 resin is 2.7, and the water content of the blended polyamide resin after drying is 700ppm.

[0199] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 220°C; the temperature of zone two is 240°C; the temperature of zone three is 260°C; the temperature of zone four is 270°C; and the temperature of zone five is 280°C.

[0200] The spinning process in step (2) includes the following steps:

[0201] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 275°C and the pressure of the spinning assembly is 12.2 MPa.

[0202] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.6 times and a heat setting temperature of 80°C.

[0203] The performance of the obtained products is listed in Tables 1 and 2.

[0204] Comparative Example 6

[0205] (1) Mix polyamide 6 resin and polyamide 66 resin evenly in a mixing bin at a ratio of 65:35 (mass ratio), and then dry them in a vacuum drum dryer at a drying temperature of 120℃ for 10 hours.

[0206] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0207] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0208] Step (1) The relative viscosity of polyamide 6 resin is 2.7, the relative viscosity of polyamide 66 resin is 2.7, and the water content of the blended polyamide resin after drying is 700ppm.

[0209] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 220°C; the temperature of zone two is 240°C; the temperature of zone three is 260°C; the temperature of zone four is 270°C; and the temperature of zone five is 280°C.

[0210] The spinning process in step (2) includes the following steps:

[0211] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 275°C and the pressure of the spinning assembly is 12.8 MPa.

[0212] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.6 times and a heat setting temperature of 80°C.

[0213] The performance of the obtained products is listed in Tables 1 and 2.

[0214] Comparative Example 7

[0215] (1) Mix polyamide 6 resin and polyamide 66 resin evenly in a mixing bin at a ratio of 50:50 (mass ratio), and then dry them in a vacuum drum dryer at a drying temperature of 90°C for 18 hours.

[0216] (2) The above-mentioned polyamide resin is heated to a molten state to form a polyamide melt, which is then extruded through a spinneret to form nascent filaments;

[0217] (3) The high-shrinkage polyamide fiber is obtained by stretching and heat-setting the nascent filament.

[0218] Step (1) The relative viscosity of polyamide 56 resin is 3.0, the relative viscosity of polyamide 66 resin is 2.8, and the water content of the blended polyamide resin after drying is 500ppm.

[0219] The heating in step (2) is carried out in a screw extruder, which is divided into five heating zones; the temperature of zone one is 245°C; the temperature of zone two is 270°C; the temperature of zone three is 290°C; the temperature of zone four is 305°C; and the temperature of zone five is 300°C.

[0220] The spinning process in step (2) includes the following steps:

[0221] The polyamide melt is ejected through the spinneret of the spinning box to form the nascent filament; the temperature of the box is 295°C and the pressure of the spinning assembly is 18.6 MPa.

[0222] In step (3), the stretching and heat setting are completed on two pairs of hot rollers, with a stretching ratio of 1.4 times and a heat setting temperature of 88°C.

[0223] The performance of the obtained products is listed in Tables 1 and 2.

[0224] Table 1

[0225]

[0226] Table 2

[0227]

[0228]

[0229] As can be seen from Tables 1 and 2, Examples 1 to 8 have a better elastic rebound rate than the comparative examples, thus exhibiting excellent anti-collapse performance, being less prone to soft collapse deformation, and possessing good fracture strength and high mechanical strength, making them less prone to fracture.

[0230] Polyamide 56 / polyamide 6 blended fibers have higher shrinkage properties than polyamide 56 / polyamide 66 blended fibers and polyamide 6 / polyamide 66 blended fibers.

[0231] Because the polyamide 56 / polyamide 6 blend fiber of the present invention has a high boiling water shrinkage rate, high shrinkage performance, and excellent softness, it can be used to produce high-shrinkage fabrics. In addition, this fabric has softness, moderate tension and strength, and a good hand feel, making it of extremely high quality and suitable for use in high-end clothing.

[0232] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-shrinkage polyamide fiber, characterized in that, The high-shrinkage polyamide fiber is a blend of polyamide 6 and polyamide 56; The high-shrinkage polyamide fiber has a boiling water shrinkage rate of 30-60%. The weight ratio of polyamide 56 to polyamide 6 is 45:55 to 60:40; In the blended fibers, the relative viscosity of the resin raw material of polyamide 56 is 2.4 to 3.5, and the relative viscosity of the resin raw material of polyamide 6 is 2.2 to 3.

5.

2. The high-shrinkage polyamide fiber as described in claim 1, characterized in that, The high-shrinkage polyamide fiber exhibits an elastic recovery rate of over 96% under 10% tensile conditions; and / or, The high-shrinkage polyamide fiber has an elastic recovery rate of over 85.5% under 20% stretching conditions.

3. The high-shrinkage polyamide fiber as described in claim 2, characterized in that, The high-shrinkage polyamide fiber has an elastic recovery rate of 96-100% under 10% stretching conditions; and / or, The high-shrinkage polyamide fiber has an elastic recovery rate of 86-90% under 20% stretching conditions.

4. The high-shrinkage polyamide fiber as described in claim 1, characterized in that, One of the raw materials for polyamide 56, 1,5-pentanediamine, is prepared from bio-based raw materials through fermentation or enzymatic conversion.

5. The high-shrinkage polyamide fiber as described in claim 1, characterized in that, The high-shrinkage polyamide fiber has a modulus of 20–45 cN / dtex; and / or, The high-shrinkage polyamide fiber has a breaking strength of 2.5–10.0 cN / dtex.

6. The high-shrinkage polyamide fiber as described in claim 5, characterized in that, The high-shrinkage polyamide fiber has a modulus of 25–40 cN / dtex; and / or, The high-shrinkage polyamide fiber has a breaking strength of 3.0 to 8.5 cN / dtex.

7. The high-shrinkage polyamide fiber as described in claim 6, characterized in that, The modulus of the high-shrinkage polyamide fiber is 30-40 cN / dtex.

8. The high-shrinkage polyamide fiber as described in claim 7, characterized in that, The high-shrinkage polyamide fiber has a breaking strength of 4.0–5.7 cN / dtex.

9. A method for preparing high-shrinkage polyamide fibers as described in any one of claims 1 to 8, characterized in that, The method includes the following steps: (1) Mix polyamide 56 and polyamide 6 resin raw materials evenly in a certain proportion, and then dry them; (2) Heat the polyamide blend obtained from step (1) to a molten state to form a polyamide melt, and extrude it to form a nascent filament; (3) The nascent filament is subjected to stretching and heat setting to obtain the high shrinkage polyamide fiber; wherein the stretching and heat setting is performed on two pairs of hot rollers and the stretching ratio of the stretching and heat setting is 1 to 2.8 times.

10. The method as described in claim 9, characterized in that, In step (3), the stretching ratio of the stretching heat setting is 1.2 to 1.8 times.

11. The method as described in claim 10, characterized in that, In step (3), the stretching ratio of the stretching heat setting is 1.3 to 1.6 times.

12. The method as described in claim 11, characterized in that, In step (3), the stretching ratio of the stretching heat setting is 1.4 to 1.6 times.

13. The method as described in claim 9, characterized in that, In step (3), The heat setting temperature is 60–150°C.

14. The method as described in claim 13, characterized in that, In step (3), The heat setting temperature is 65–95°C.

15. The method as described in claim 14, characterized in that, In step (3), The heat setting temperature is 70–93°C.

16. The method as described in claim 15, characterized in that, In step (3), The heat setting temperature is 80–90°C.

17. The method as described in claim 9, characterized in that, In step (1), The drying temperature is 60–120°C, and the drying time is 8–30 hours; and / or, The moisture content of the dried blended polyamide resin is ≤1000ppm.

18. The method as described in claim 17, characterized in that, In step (1), The moisture content of the dried blended polyamide resin is 200–900 ppm.

19. The method as described in claim 18, characterized in that, In step (1), The relative viscosity of the polyamide 56 resin raw material is 2.6 to 3.2; and / or, The relative viscosity of the polyamide 6 resin raw material is 2.4–3.0; and / or, The moisture content of the dried blended polyamide resin is 300–800 ppm.

20. The method as described in claim 19, characterized in that, In step (1), The relative viscosity of the polyamide 56 resin raw material is 2.7 to 3.1; and / or, The relative viscosity of the polyamide 6 resin raw material is 2.5 to 2.8; and / or, The moisture content of the dried blended polyamide resin is 400–600 ppm.

21. A high-shrinkage polyamide fiber as described in any one of claims 1 to 8 comprises civilian filaments, industrial filaments, bulked textured yarns, monofilaments, and staple fibers.

22. The use of a high-shrinkage polyamide fiber as described in any one of claims 1 to 8 in the preparation of high-grade imitation suede fabrics, imitation peach skin fabrics, high-density fabrics, imitation silk fabrics and / or heterogeneous shrinkage blended fiber fabrics.

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