Polyamide 56 low boiling point water shrinkable fiber, its manufacturing method and use

Abstract

The present invention relates to the technical field of polyamide materials and provides low-boiling water shrinkage polyamide 56 pre-oriented yarn and polyamide 56 stretch-textured yarn, their manufacturing process, and their use. The raw material for manufacturing the polyamide 56 fiber includes a polyamide 56 resin obtained by polymerizing 1,5-pentanediamine and adipic acid or 1,5-pentanediamine monomer and adipic acid monomer. The polyamide 56 fiber has a boiling water shrinkage of 9% or less. The polyamide 56 fiber includes low-boiling water shrinkage polyamide 56 pre-oriented yarn and low-boiling water shrinkage polyamide 56 stretch-textured yarn. The polyamide 56 fiber has good mechanical properties, dye uniformity, and dimensional stability. The manufacturing process for the polyamide 56 fiber does not require modification to existing equipment for texturing polyamide fibers, thereby reducing production costs.

Description

[Technical field]

[0001] The present invention relates to the technical field of polyamide materials, and provides polyamide 56 pre-oriented yarn and polyamide 56 stretch textured yarn with low boil-off shrinkage, their manufacturing process and their use. [Background technology]

[0002] Polyamide fibers have a large boiling water shrinkage rate, and shrink significantly during the dyeing process, which is prone to uneven dyeing. The shrinkage rate is especially large during the Robin dyeing process. The yarn has different surface tensions in the outer and inner parts of the package. The yarn adjacent to the bobbin has a large tension, which makes it difficult for the dye to penetrate, making it difficult to dye, and causing chromatic aberration between the outer and inner parts of the package. Secondly, during the unwinding of the package, the tension changes after shrinkage, making unwinding difficult and causing the yarn to break, which increases the difficulty of processing and the production cost. The yarn shrinks greatly in boiling water, which reduces the width of the fabric during the dyeing process, and therefore makes it difficult to control the width of the fabric. In particular, if the shrinkage rate is large when the fabric is subsequently made into clothing and the clothing is washed in hot water, the shape retention of the clothing is poor.

[0003] There have been patents reporting polyamide 56 medium strength and high strength yarns and their preparation methods. For example, patent CN 106835329 A discloses polyamide 5X medium strength yarns and their preparation process. Patent CN 106868624 A discloses polyamide 5X high strength yarns and their preparation process. Such yarns have a low boiling water shrinkage of 2-7%, mainly due to their different processing methods. Multiple pairs of heat rollers are used for drawing the yarns during processing, and high temperature settings are also used. The high crystallinity and orientation degree of such fibers, with a small proportion of amorphous regions, ultimately indicate low boiling water shrinkage and good dimensional stability. Patent CN 106868623 A discloses bio-based, highly elastic, hygroscopic, and easily dyed long-chain carbon polyamide 5X fibers and their preparation process. The fibers also have a low boiling water shrinkage of 3-10%. The raw materials used are long carbon chain polyamide 510, 512, etc., non-short carbon chain polyamide 56, and the continuous bulking filament processing method is applied. Patent CN 100489168 C discloses a process for producing polyester stretch-textured yarn (DTY) with low boiling water shrinkage. The yarn has low boiling water shrinkage, and the material of the yarn is polyester. The polyester fiber has a low moisture content of 0.4%, so it is not easy to absorb water and has good dimensional stability. Secondly, two stretching rollers and two stretching hot boxes are used for polyester stretch-textured yarn. The stretching time and curing time are relatively long, the crystallinity and orientation degree of the yarn are high, and its boiling water shrinkage rate is also relatively low. However, it is difficult to reduce the shrinkage rate of the yarn in boiling water by applying the polyamide pre-orientation and stretch-textured yarn process. Summary of the Invention [Problem to be solved by the invention]

[0004] A first object of the present invention is to provide a polyamide 56 fiber which has low boil-off shrinkage while having good mechanical properties and dye uniformity.

[0005] The second object of the present invention is to provide a process for producing polyamide 56 fibers with low boiling water shrinkage. In such a process, the viscosity, oligomer content, molecular weight and molecular weight distribution, and moisture content of the polyamide 56 resin are adjusted by optimizing its quality. Furthermore, by optimizing the spinning process for polyamide 56 pre-oriented yarn, polyamide 56 pre-oriented yarn with low boiling water shrinkage and good mechanical properties is obtained. Finally, polyamide 56 stretch-textured yarn with good mechanical properties, dyeing uniformity and low boiling water shrinkage is obtained by texturing polyamide 56 pre-oriented yarn and adjusting the texturing process, specifically, increasing the draw ratio, increasing the draw temperature, increasing the entanglement pressure, decreasing the winding speed during texturing, applying an overfeed process, increasing the crystallinity and orientation of the polyamide 56 stretch-textured yarn, and decreasing the subsequent stress relaxation.

[0006] A third object of the present invention is to provide a use of polyamide 56 fiber with low boil-off shrinkage.

[0007] The polyamide 56 fiber with low boiling water shrinkage is used in knitting and weaving, and is used in the fields of underwear, shirts, suits, down jackets, outdoor jackets, socks, bags and suitcases, curtains, shoe materials, embroidery threads, labels, sofa covers, uniforms, sportswear, and elastic tapes, etc. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides the following solutions:

[0009] [Low boiling point water shrinkage polyamide 56 fiber] The present invention provides a polyamide 56 fiber, in which a raw material for producing the polyamide 56 fiber contains 1,5-pentanediamine and adipic acid, or a polyamide 56 resin obtained by polymerizing a 1,5-pentanediamine monomer and an adipic acid monomer, and the polyamide 56 fiber has a boiling water shrinkage of 9% or less.

[0010] In some preferred embodiments of the present invention, the polyamide 56 fibers include low boil-off shrinkage polyamide 56 pre-oriented yarns and low boil-off shrinkage polyamide 56 stretch-textured yarns.

[0011] In some preferred embodiments of the invention, the polyamide 56 resin has an oligomer content of 1.2 wt% or less, and preferably 0.8 wt% or less, for example, 0.2-1.2 wt%, 0.4-0.8 wt%, or 0.4-1.2 wt%.

[0012] In some preferred embodiments of the invention, the oligomer is selected from the following structures: [ka] In the formula, n1 and n2 are each selected from integers of 1 to 8, and m1 and m2 are 4. Preferably, n1 and n2 are each selected from integers of 1 to 6; more preferably, n1 and n2 are each independently an integer of 1 to 5; even more preferably, n1 is 1, 2, 3 or 4; and n2 is 1, 2, 3, 4 or 5.

[0013] In one preferred embodiment of the present invention, the polyamide 56 fibers include bright fibers, semi-dull fibers, and full-dull polyamide 56 fibers.

[0014] In a preferred embodiment of the present invention, the low boiling water shrinkage polyamide 56 pre-oriented yarn has a boiling water shrinkage of 9% or less, more preferably 8% or less, and even more preferably 7% or less. In some preferred embodiments of the present invention, the low boiling water shrinkage polyamide 56 pre-oriented yarn has a boiling water shrinkage of 3 to 9%, more preferably 3 to 8%, and even more preferably 3 to 7%, for example, 3.1%, 3.5%, 4.5%, 4.9%, or 5.4%.

[0015] In some preferred embodiments of the present invention, the polyamide 56 pre-oriented yarn has a fineness of 10 to 300 dtex, preferably 20 to 200 dtex, more preferably 30 to 100 dtex, and even more preferably 50 to 80 dtex; and / or the polyamide 56 pre-oriented yarn has a breaking strength of 3.0 to 4.5 cN / dtex, preferably 3.3 to 4.3 cN / dtex, more preferably 3.5 to 4.1 cN / dtex, and even more preferably 3.7 to 3.9 cN / dtex; and / or the polyamide 56 pre-oriented yarn has a breaking elongation of 60 to 90%, preferably 65 to 85%, more preferably 70 to 80%, and even more preferably 73 to 78%; and / or the polyamide 56 pre-oriented yarn has a dye uniformity (gray scale) of preferably grade 3 or higher, more preferably grade 3.5 or higher, even more preferably grade 4.0 or higher, and particularly preferably grade 4.5 or higher.

[0016] In some preferred embodiments of the present invention, the low boiling water shrinkage polyamide 56 stretch-textured yarn has a boiling water shrinkage of 8% or less, more preferably 7% or less, and even more preferably 6% or less. In some preferred embodiments of the present invention, the polyamide 56 stretch-textured yarn has a boiling water shrinkage of 2 to 8%, more preferably 2 to 7%, and even more preferably 2 to 6%, for example, 2.5%, 3.1%, 3.5%, 4.5%, 4.9%, or 5.4%.

[0017] In some preferred embodiments of the present invention, the polyamide 56 stretch-textured yarn has a fineness of 10 to 200 dtex, preferably 20 to 100 dtex, more preferably 30 to 80 dtex, and even more preferably 40 to 60 dtex; and / or the polyamide 56 stretch-textured yarn has a breaking strength of 3.5 to 5.5 cN / dtex, preferably 3.8 to 5.0 cN / dtex, more preferably 4.0 to 4.7 cN / dtex, and even more preferably 4.3 to 4.5 cN / dtex; and / or the polyamide 56 stretch-textured yarn has a breaking elongation of 20 to 50%, preferably 25 to 45%, more preferably 30 to 40%, and even more preferably 33 to 36%; and / or the polyamide 56 stretch-textured yarn has a crystallinity of 60% or more, preferably 63% or more, more preferably 66% or more, and even more preferably 68% or more. In some preferred embodiments of the present invention, the polyamide 56 stretch-textured yarn has a crystallinity of 60 to 80%, preferably 63 to 77%, more preferably 66 to 74%, and even more preferably 68 to 72%; and / or the polyamide 56 stretch-textured yarn has a degree of orientation of 60% or more, preferably 65% ​​or more, more preferably 70% or more, and even more preferably 73% or more. In some preferred embodiments of the present invention, the polyamide 56 stretch-textured yarn has an orientation degree of 60 to 90%, preferably 65 to 85%, more preferably 70 to 80%, and even more preferably 73 to 78%; and / or the polyamide 56 stretch-textured yarn has a dye uniformity (gray scale) of preferably grade 3 or higher, preferably grade 3.5 or higher, more preferably grade 4.0 or higher, and even more preferably grade 4.5 or higher.

[0018] [Manufacturing process of low boiling water shrinkable polyamide 56 fiber] The present invention further provides a process for producing low boil-water shrinkable polyamide 56 pre-oriented yarn, the process comprising the steps of: (1) polymerizing 1,5-pentanediamine and adipic acid to form a polyamide 56 melt or heating a polyamide 56 resin to a molten state in a screw to form a polyamide 56 melt; (2) conveying the polyamide 56 melt through a pipe into a spinning pot, precisely metering the melt with a metering pump, and then injecting it into a spinning assembly and extruding it through a spinneret orifice; (3) Cooling, spin finishing, drawing and winding the extruded as-spun fibers to obtain polyamide 56 pre-oriented yarns.

[0019] In step (1), the polyamide 56 resin has a relative viscosity of 2.4 to 2.8, preferably 2.5 to 2.7, and the polyamide 56 resin has an oligomer content of 1.2 wt% or less, preferably 0.8 wt% or less, for example, the polyamide 56 resin has an oligomer content of 0.2 to 1.2 wt%, 0.4 to 0.8 wt%, or 0.4 to 1.2 wt%; and / or the polyamide 56 resin has a water content of 600 to 1200 ppm, preferably 800 to 1000 ppm; and / or the polyamide 56 resin has a water content of 15,000 to 22,000 ppm. , preferably having a number average molecular weight of 18,000 to 20,000, or having a molecular weight distribution of 1.0 to 2.0, and preferably 1.2 to 1.8; and / or the screw is heated in four zones, where the temperature of the first zone is 245 to 260°C, preferably 250 to 255°C; the temperature of the second zone is 260 to 275°C, and preferably 265 to 270°C; the temperature of the third zone is 275 to 285°C, and preferably 278 to 283°C; and the temperature of the fourth zone is 280 to 285°C, and preferably 282 to 284°C; In step (2), the temperature of the pot is 275-285°C, preferably 280-283°C, and the pressure of the assembly is 13-20 MPa, preferably 15-18 MPa; In step (3), the cooling preferably includes cooling by side air blow or cross air blow, preferably cooling by cross air blow, the air speed is preferably 0.2-0.6 m / s, more preferably 0.3-0.5 m / s, and / or the air temperature is 18-25°C, preferably 20-23°C, more preferably 21-22°C, and / or the spinning finish is performed with an oil roll; and the oil pick-up is 0.2-0.8 wt%, preferably 0.3-0.7 wt%, more preferably 0.4-0.5 wt%, and / or the take-up speed is 4000-5500 m / min, preferably 4300-5000 m / min, more preferably 4500-4800 m / min.

[0020] The present invention further provides a process for producing low boil-water shrinkable polyamide 56 stretch textured yarn, the process comprising the steps of: a) directing the polyamide 56 pre-oriented yarn by a guide to a first roller; conveying it through a twist stopper and hot drawing the pre-oriented yarn in a first hot box; b) cooling and setting the pre-oriented yarn on a cooling plate, conveying it through a false twister, a second roller, and an interlacing device, and spin-finishing it with an oil roll; and c) Winding the pre-oriented yarn to obtain polyamide 56 stretch textured yarn.

[0021] and / or the hot stretching ratio is 1.1 to 1.5, preferably 1.15 to 1.4, more preferably 1.2 to 1.3; and / or the hot stretching temperature is 150 to 220°C, preferably 160 to 200°C, more preferably 170 to 180°C; and / or the speed ratio D / Y of the false twisting machine is 1.3 to 2.2, preferably 1.5 to 2.0, more preferably 1.7 to 1.8; and / or the pressure of the compressed air in the interlacing device is 0.3 to 1.5 MPa, preferably 0.5 to 1.2 MPa, more preferably 0.7 to 0.8 MPa; and / or the winding speed is 300 to 800 m / min, preferably 400 to 700 m / min, more preferably 500 to 600 m / min; and / or the winding overfeed is 2 to 8%, preferably 3 to 6%, more preferably 4 to 5%.

[0022] The present invention further provides the use of polyamide 56 fibers in knitted or woven fabrics.

[0023] Said low boiling water shrinkage polyamide 56 fiber is used in knitting and woven fabrics, including but not limited to the fields of underwear, shirts, suits, down jackets, outdoor jackets, socks, bags and suitcases, curtains, shoe materials, embroidery threads, labels, sofa covers, uniforms, sportswear, elastic tapes and so on. Effect of the Invention

[0024] The advantageous effects of the present invention provided by the above-mentioned solution are as follows: Firstly, the raw materials for producing the low boiling water shrinkage polyamide 56 fiber of the present invention can be prepared by biological processes, and therefore are green materials. They do not depend on petroleum resources and do not cause serious pollution to the environment. They can also reduce carbon dioxide emissions and greenhouse effect.

[0025] Secondly, the low boiling water shrinkage polyamide 56 fiber of the present invention has good mechanical properties, dyeing uniformity and dimensional stability.Meanwhile, the obtained polyamide 56 fiber has high quality grade by optimizing the quality of polyamide 56 resin, spinning and texturing process.

[0026] Thirdly, the low boiling water shrinkage polyamide 56 fiber of the present invention can be produced by using conventional polyamide 6 texturing equipment. The application requirements can be met by optimizing the process without modifying the texturing equipment, thus reducing the production cost. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] In order to make the objectives, technical solutions and advantages of the present disclosure clearer, the technical solutions of the present disclosure are clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by those skilled in the art based on the embodiments in the present disclosure without creative work shall fall within the protection scope of the present disclosure.

[0028] (1) Fineness: measured according to GB / T 14343. (2) Breaking strength: measured in accordance with GB / T 14344. (3) Elongation at break: measured in accordance with GB / T 14344. (4) Heat shrinkage: Measured in accordance with FZ / T 50030. (5) Boiling water shrinkage: measured in accordance with GB / 6505. (6) Dyeing uniformity (gray card) / grade: Measured in accordance with FZ / T 50008 test method for dyeing uniformity of nylon filaments.

[0029] (7) Relative Viscosity: The relative viscosity of polyamide 56 resin was measured by using concentrated sulfuric acid and an Ubbelohde viscometer. 0.25±0.0002 g of dried polyamide 56 resin sample was precisely weighed out, 50 mL of concentrated sulfuric acid (96%) was added to obtain a polyamide 56 resin sample solution, and the solution was placed in a water bath at 25°C for a flow time of concentrated sulfuric acid t 0 The flow time of the polyamide 56 resin sample solution is measured and recorded. The relative viscosity is calculated according to the following formula: Relative viscosity VN=t / t 0 ; t represents the flow time of the solution, and t 0 represents the flow time of the solvent.

[0030] (8) Moisture content: The water content is measured by a Karl Fischer water titrator.

[0031] (9) Crystallinity: The fiber samples are analyzed using a Nippon Rigaku D / max-2550PC X-ray diffractometer under the following conditions: Cu target wavelength λ k α 1 = 1.54056 Å, voltage 20-40 kV, current 10-450 mA, measurement angle 2θ in the range of 5-40°. The polyamide 56 fiber samples used for measuring crystallinity were well chopped and the mass of the samples was greater than 0.2 g. The polyamide 56 fiber samples used for measuring crystallite orientation were well combed. A bundle of 30 mm in length was used for the test. Software such as Origin was used for data processing to analyze and calculate the crystallinity and orientation of the fibers.

[0032] The following formula is used to calculate the crystallinity:

number

number

number

[0033] (10) Orientation: Measured using an acoustic speed and direction measuring device. (11) Number average molecular weight: measured by standard GPC. (12) Molecular weight distribution: measured by gel permeation chromatography (GPC).

[0034] (13) Oligomer content test: Water extraction method (gravimetric determination): 8 g of polyamide 56 resin dried at 130°C for 7 hours is weighed out accurately and placed in a 500 mL round bottom flask. 400 g of water is added. After refluxing in a heating mantle for 36 hours, the solution is decanted. The particles are dried in a constant weight beaker at 130°C for 7 hours, then sealed in an aluminum plastic bag, cooled, and weighed. The weight loss is calculated.

[0035] According to the methods disclosed in CN108503826A and CN108503824A, polyamide 56 resin (in chip form) with a relative viscosity of 2.4-2.8 and oligomer content of 1.2 wt% or less is prepared. Polyamide 6 chips with a relative viscosity of 2.5-2.7 are commercially available from Ruimeifu Industrial Co., Ltd. (Jiangsu).

[0036] Example 1: Preparation of low boil-water shrinkable polyamide 56 pre-oriented yarn (1) Heating polyamide 56 resin to a molten state in a screw to form a polyamide 56 melt; (2) conveying the polyamide 56 melt through a pipe to a spinning pot, precisely metering the melt with a metering pump, which then injects it into a spinning assembly and extrudes it through a spinneret orifice; and (3) The extruded as-spun fibers are cooled, spin-finished, drawn and wound to obtain polyamide 56 pre-oriented yarns.

[0037] In step (1), the polyamide 56 resin had a relative viscosity of 2.5, an oligomer content of 0.8 wt%, a water content of 800 ppm, a number average molecular weight of 18,000, and a molecular weight distribution of 1.6; The screw was heated in four zones, the first zone having a temperature of 250° C., the second zone having a temperature of 270° C., the third zone having a temperature of 285° C., and the fourth zone having a temperature of 280° C.; In step (2), the temperature of the spinning pot was 283° C. and the assembly pressure was 18 MPa; In step (3), cooling was performed by cross air blowing, the air speed was 0.5 m / s, and the air temperature was 22°C; Spin finishing was performed on an oil roll with an oil pick-up of 0.5 wt. % and a take-up speed of 4,500 m / min.

[0038] Example 2: Preparation of low boil-water shrinkable polyamide 56 pre-oriented yarn (1) Heating polyamide 56 resin to a molten state in a screw to form a polyamide 56 melt; (2) conveying the polyamide 56 melt through a pipe to a spinning pot, precisely metering the melt with a metering pump, which then injects it into a spinning assembly and extrudes it through a spinneret orifice; and (3) The extruded as-spun fibers are cooled, spin-finished, drawn and wound to obtain polyamide 56 pre-oriented yarns.

[0039] In step (1), the polyamide 56 resin had a relative viscosity of 2.7, an oligomer content of 1.0 wt%, a water content of 900 ppm, a number average molecular weight of 19,000, and a molecular weight distribution of 1.8; The screw was heated in four zones, the first zone having a temperature of 255° C., the second zone having a temperature of 270° C., the third zone having a temperature of 280° C., and the fourth zone having a temperature of 285° C.; In step (2), the temperature of the spinning pot was 280° C. and the assembly pressure was 14 MPa; In step (3), cooling was performed by cross air blowing, the air speed was 0.4 m / s, and the air temperature was 24°C; Spin finishing was performed with an oil roll, with an oil pick-up of 0.6 wt. % and a take-up speed of 4,800 m / min.

[0040] Example 3: Preparation of low boil-water shrinkable polyamide 56 pre-oriented yarn (1) Heating polyamide 56 resin to a molten state in a screw to form a polyamide 56 melt; (2) conveying the polyamide 56 melt through a pipe to a spinning pot, precisely metering the melt with a metering pump, which then injects it into a spinning assembly and extrudes it through a spinneret orifice; and (3) The extruded as-spun fibers are cooled, spin-finished, drawn and wound to obtain polyamide 56 pre-oriented yarns.

[0041] In step (1), the polyamide 56 resin had a relative viscosity of 2.4, an oligomer content of 1.15 wt%, a water content of 1000 ppm, a number average molecular weight of 20,000, and a molecular weight distribution of 1.7; The screw was heated in four zones, the first zone having a temperature of 250° C., the second zone having a temperature of 272° C., the third zone having a temperature of 283° C., and the fourth zone having a temperature of 282° C.; and In step (2), the temperature of the spinning pot was 278° C. and the assembly pressure was 16 MPa; In step (3), cooling was performed by cross air blowing, the air speed was 0.5 m / s, and the air temperature was 20°C; Spin finishing was performed with an oil roll, with an oil pick-up of 0.3 wt. % and a take-up speed of 4,300 m / min.

[0042] Example 4: Preparation of low boil-water shrinkable polyamide 56 pre-oriented yarn (1) Heating polyamide 56 resin to a molten state in a screw to form a polyamide 56 melt; (2) conveying the polyamide 56 melt through a pipe to a spinning pot, precisely metering the melt with a metering pump, which then injects it into a spinning assembly and extrudes it through a spinneret orifice; and (3) The extruded as-spun fibers are cooled, spin-finished, drawn and wound to obtain polyamide 56 pre-oriented yarns.

[0043] In step (1), the polyamide 56 resin had a relative viscosity of 2.6, an oligomer content of 0.9 wt%, a water content of 700 ppm, a number average molecular weight of 16,000, and a molecular weight distribution of 1.4; The screw was heated in four zones, the first zone having a temperature of 255° C., the second zone having a temperature of 270° C., the third zone having a temperature of 280° C., and the fourth zone having a temperature of 280° C.; In step (2), the temperature of the spinning pot was 285° C. and the assembly pressure was 18 MPa; In step (3), cooling was performed by cross air blowing, the air speed was 0.3 m / s, and the air temperature was 21°C; Spin finishing was performed with an oil roll, with an oil pick-up of 0.4 wt. % and a take-up speed of 4,600 m / min.

[0044] Example 5: Preparation of low boil-water shrinkable polyamide 56 pre-oriented yarn (1) Heating polyamide 56 resin to a molten state in a screw to form a polyamide 56 melt; (2) conveying the polyamide 56 melt through a pipe to a spinning pot, precisely metering the melt with a metering pump, which then injects it into a spinning assembly and extrudes it through a spinneret orifice; and (3) The extruded as-spun fibers are cooled, spin-finished, drawn and wound to obtain polyamide 56 pre-oriented yarns.

[0045] In step (1), the polyamide 56 resin had a relative viscosity of 2.8, an oligomer content of 1.2 wt%, a water content of 600 ppm, a number average molecular weight of 22,000, and a molecular weight distribution of 1.2; The screw was heated in four zones, the first zone having a temperature of 255° C., the second zone having a temperature of 265° C., the third zone having a temperature of 280° C., and the fourth zone having a temperature of 285° C.; and In step (2), the temperature of the spinning pot was 282° C. and the assembly pressure was 13 MPa; In step (3), cooling was performed by cross air blowing, the air speed was 0.5 m / s, and the air temperature was 20°C; Spin finishing was performed on an oil roll with an oil pick-up of 0.5 wt. % and a take-up speed of 4,800 m / min.

[0046] Comparative Example 1a: Preparation of polyamide 6 pre-oriented yarn (1) Heating polyamide 6 resin to a molten state in a screw to form a polyamide 6 melt; (2) conveying the polyamide 6 melt through a pipe to a spinning pot, precisely metering the melt with a metering pump, which then injects it into a spinning assembly and extrudes it through a spinneret orifice; and (3) The extruded as-spun fibers are cooled, spin-finished, drawn and wound to obtain polyamide 6 pre-oriented yarns.

[0047] In step (1), the polyamide 6 resin had a relative viscosity of 2.4, an oligomer content of 1.0 wt%, a water content of 1000 ppm, a number average molecular weight of 20,000, and a molecular weight distribution of 1.7; The screw was heated in four zones, the first zone having a temperature of 225° C., the second zone having a temperature of 245° C., the third zone having a temperature of 260° C., and the fourth zone having a temperature of 265° C.; and In step (2), the temperature of the spinning pot is 260° C. and the pressure of the assembly is 14 MPa; and In step (3), cooling was performed by cross air blowing, the air speed was 0.5 m / s, and the air temperature was 20°C; Spin finishing was performed with an oil roll, with an oil pick-up of 0.3 wt. % and a take-up speed of 4,300 m / min.

[0048] Comparative Example 1b: Preparation of polyamide 56 pre-oriented yarn A polyamide 56 resin was prepared according to the polyamide 56 manufacturing process disclosed in JP4165106B2. (1) Heating polyamide 56 resin to a molten state in a screw to form a polyamide 56 melt; (2) conveying the polyamide 56 melt through a pipe to a spinning pot, precisely metering the melt with a metering pump, which then injects it into a spinning assembly and extrudes it through a spinneret orifice; and (3) The extruded as-spun fibers are cooled, spin-finished, drawn and wound to obtain polyamide 56 pre-oriented yarns.

[0049] In step (1), the polyamide 56 resin had a relative viscosity of 2.4, an oligomer content of 3.1 wt%, a water content of 1000 ppm, a number average molecular weight of 20,000, and a molecular weight distribution of 1.7; The screw was heated in four zones, the first zone having a temperature of 250° C., the second zone having a temperature of 272° C., the third zone having a temperature of 283° C., and the fourth zone having a temperature of 282° C.; and In step (2), the temperature of the spinning pot is 278° C. and the pressure of the assembly is 16 MPa; and In step (3), cooling was performed by cross air blowing, the air speed was 0.5 m / s, and the air temperature was 20°C; Spin finishing was performed with an oil roll, with an oil pick-up of 0.3 wt. % and a take-up speed of 4,300 m / min.

[0050] Example 6: Preparation of low boil-water shrinkable polyamide 56 stretch-textured yarn A polyamide 56 stretch-textured yarn was prepared from the polyamide 56 pre-oriented yarn prepared in Example 1. The manufacturing process for low boil-water shrinkable polyamide 56 stretch textured yarn included the following steps: First, the polyamide 56 pre-oriented yarn is guided toward the first roller, transported through a twist stopper, and hot-drawn in the first hot box; next, the pre-oriented yarn is cooled and set on a cooling plate, transported through a false twister, a second roller, and an interlacing device, and finished by spinning with an oil roll; and finally, the pre-oriented yarn is wound to obtain a polyamide 56 stretch-textured yarn.

[0051] The stretching ratio was 1.3, and the stretching temperature was 180°C; The speed ratio D / Y of the false twisting machine was 1.65; The pressure of the compressed air in the intertwining device was 0.6 MPa, the winding speed was 650 m / min, and the winding overfeed was 3%.

[0052] Example 7: Preparation of low boil-water shrinkable polyamide 56 stretch-textured yarn A polyamide 56 stretch-textured yarn was prepared from the polyamide 56 pre-oriented yarn prepared in Example 2. The manufacturing process for low boil-water shrinkable polyamide 56 stretch textured yarn included the following steps: First, the polyamide 56 pre-oriented yarn is guided toward the first roller, transported through a twist stopper, and hot-drawn in the first hot box; next, the pre-oriented yarn is cooled and set on a cooling plate, transported through a false twister, a second roller, and an interlacing device, and finished by spinning with an oil roll; and finally, the pre-oriented yarn is wound to obtain a polyamide 56 stretch-textured yarn.

[0053] The stretching ratio was 1.25 and the stretching temperature was 200°C; The speed ratio D / Y of the false twisting machine was 1.8; The pressure of the compressed air in the intertwining device was 0.8 MPa, the winding speed was 500 m / min, and the winding overfeed was 5%.

[0054] Example 8: Preparation of low boil-water shrinkable polyamide 56 stretch-textured yarn A polyamide 56 stretch-textured yarn was prepared from the polyamide 56 pre-oriented yarn prepared in Example 3. The manufacturing process for low boil-water shrinkable polyamide 56 stretch textured yarn included the following steps: First, the polyamide 56 pre-oriented yarn is guided toward the first roller, transported through a twist stopper, and hot-drawn in the first hot box; next, the pre-oriented yarn is cooled and set on a cooling plate, transported through a false twister, a second roller, and an interlacing device, and finished by spinning with an oil roll; and finally, the pre-oriented yarn is wound to obtain a polyamide 56 stretch-textured yarn.

[0055] The stretching ratio was 1.3, and the stretching temperature was 160°C; The speed ratio D / Y of the false twisting machine was 1.75; The pressure of the compressed air in the interlacing device was 0.7 MPa, the winding speed was 550 m / min, and the winding overfeed was 4%.

[0056] Example 9: Preparation of low boil-water shrinkable polyamide 56 stretch-textured yarn A polyamide 56 stretch-textured yarn was prepared from the polyamide 56 pre-oriented yarn prepared in Example 4. The manufacturing process for low boil-water shrinkable polyamide 56 stretch textured yarn included the following steps: First, the polyamide 56 pre-oriented yarn is guided toward the first roller, transported through a twist stopper, and hot-drawn in the first hot box; next, the pre-oriented yarn is cooled and set on a cooling plate, transported through a false twister, a second roller, and an interlacing device, and finished by spinning with an oil roll; and finally, the pre-oriented yarn is wound to obtain a polyamide 56 stretch-textured yarn.

[0057] The stretching ratio was 1.28, and the stretching temperature was 170°C; The speed ratio D / Y of the false twisting machine was 1.65; The pressure of the compressed air in the intertwining device was 0.3 MPa, the winding speed was 450 m / min, and the winding overfeed was 6%.

[0058] Example 10: Preparation of low boil-water shrinkable polyamide 56 stretch-textured yarn A polyamide 56 stretch-textured yarn was prepared from the polyamide 56 pre-oriented yarn prepared in Example 5. The manufacturing process for low boil-water shrinkable polyamide 56 stretch textured yarn included the following steps: First, the polyamide 56 pre-oriented yarn is guided toward the first roller, transported through a twist stopper, and hot-drawn in the first hot box; next, the pre-oriented yarn is cooled and set on a cooling plate, transported through a false twister, a second roller, and an interlacing device, and finished by spinning with an oil roll; and finally, the pre-oriented yarn is wound to obtain a polyamide 56 stretch-textured yarn.

[0059] The stretching ratio was 1.2, and the stretching temperature was 180°C; The speed ratio D / Y of the false twisting machine was 1.7; The pressure of the compressed air in the interlacing device was 0.6 MPa, the winding speed was 350 m / min, and the winding overfeed was 2%.

[0060] Comparative Example 2: A polyamide 56 stretch-textured yarn was prepared from the polyamide 56 pre-oriented yarn prepared in Example 3. The manufacturing process for polyamide 56 stretch textured yarn included the following steps: First, the polyamide 56 pre-oriented yarn is guided toward the first roller, transported through a twist stopper, and hot-drawn in the first hot box; next, the pre-oriented yarn is cooled and set on a cooling plate, transported through a false twister, a second roller, and an interlacing device, and finished by spinning with an oil roll; and finally, the pre-oriented yarn is wound to obtain a polyamide 56 stretch-textured yarn.

[0061] The stretching ratio was 1.02, and the stretching temperature was 160°C; The speed ratio D / Y of the false twisting machine was 1.75; The pressure of the compressed air in the interlacing device was 0.7 MPa, the winding speed was 550 m / min, and the winding overfeed was 4%.

[0062] Comparative Example 3: A polyamide 56 stretch-textured yarn was prepared from the polyamide 56 pre-oriented yarn prepared in Example 3. The manufacturing process for polyamide 56 stretch textured yarn included the following steps: First, the polyamide 56 pre-oriented yarn is guided toward the first roller, transported through a twist stopper, and hot-drawn in the first hot box; next, the pre-oriented yarn is cooled and set on a cooling plate, transported through a false twister, a second roller, and an interlacing device, and finished by spinning with an oil roll; and finally, the pre-oriented yarn is wound to obtain a polyamide 56 stretch-textured yarn.

[0063] The stretching ratio was 1.3, and the stretching temperature was 160°C; The speed ratio D / Y of the false twisting machine was 1.75; The pressure of the compressed air in the interlacing device was 0.6 MPa, the winding speed was 900 m / min, and the winding overfeed was 4%.

[0064] Comparative Example 4: Polyamide 6 stretch-textured yarn was prepared from the polyamide 6 pre-oriented yarn prepared in Comparative Example 1a. The manufacturing process for polyamide 6 stretch textured yarn included the following steps: First, the polyamide 6 pre-oriented yarn is guided toward a first roller, transported through a twist stopper, and hot-drawn in a first hot box; next, the pre-oriented yarn is cooled and set on a cooling plate, transported through a false twister, a second roller, and an interlacing device, and finished by spinning with an oil roll; and finally, the pre-oriented yarn is wound to obtain a polyamide 6 stretch-textured yarn.

[0065] The stretching ratio was 1.2, and the stretching temperature was 180°C; The speed ratio D / Y of the false twisting machine was 1.7; The pressure of the compressed air in the interlacing device was 0.6 MPa, the winding speed was 350 m / min, and the winding overfeed was 2%.

[0066] Comparative Example 5: Polyamide 56 stretch-textured yarn was prepared from the polyamide 56 pre-oriented yarn prepared in Comparative Example 1b according to the process described for the preparation of polyamide 56 stretch-textured yarn in Example 8.

[0067] Table 1 shows the test results of the parameters of the pre-oriented yarns and the stretch-textured yarns prepared in Examples 1 to 10 and the Comparative Example. [Table 1]

[0068] Compared with the polyamide fibers prepared in Comparative Examples 2 to 5, the polyamide 56 fibers prepared in Examples 6 to 10 according to the present invention had low boiling water shrinkage and good mechanical properties. In addition, the polyamide 56 fibers according to the present invention had good dyeing uniformity and dimensional stability. In addition, the polyamide 56 fibers prepared in Examples 6 to 10 were significantly better than those prepared in Comparative Examples 2 to 5.

[0069] Finally, it should be noted that the above embodiments are only used to describe the technical solutions of the present invention, but are not intended to limit them. Although the present invention has been described in detail using the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can be further modified, or some or all of the technical features can be replaced equally. These modifications or replacements do not cause the spirit of the corresponding technical solutions to depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A polyamide 56 fiber, characterized in that a raw material for producing the polyamide 56 fiber contains 1,5-pentanediamine and adipic acid, or a polyamide 56 resin obtained by polymerizing 1,5-pentanediamine and adipic acid; The polyamide 56 fibers include polyamide 56 pre-oriented yarns having a boiling water shrinkage of 7% or less, a fineness of 50 to 80 dtex, and a breaking elongation of 78 to 90%, and polyamide 56 stretch-textured yarns having a boiling water shrinkage of 2 to 5.5%, a fineness of 40 to 66 dtex, and a breaking elongation of 33 to 40%, and The polyamide 56 resin has an oligomer content of 1.2 wt.% or less. Polyamide 56 fiber.

2. 2. The polyamide 56 fiber according to claim 1 , the polyamide 56 resin has an oligomer content of 0.8 wt% or less; The oligomer is selected from the following structures: 【Chemistry 1】 wherein n1 and n2 are each selected from an integer of 1 to 8, m1 and m2 are 4, preferably n1 and n2 are each selected from an integer of 1 to 6; more preferably n1 and n2 are each independently an integer of 1 to 5; even more preferably n1 is 1, 2, 3 or 4; and n2 is 1, 2, 3, 4 or 5; and / or The polyamide 56 fiber includes bright fiber, semi-dull fiber and full-dull polyamide 56 fiber.

3. 3. The polyamide 56 fiber according to claim 1 or 2, the polyamide 56 pre-oriented yarn has a breaking strength of 3.0 to 4.5 cN / dtex, preferably 3.3 to 4.3 cN / dtex, more preferably 3.5 to 4.1 cN / dtex, and even more preferably 3.7 to 3.9 cN / dtex; and / or The polyamide 56 fiber is characterized in that the polyamide 56 pre-oriented yarn has a dye uniformity (gray scale) of 3 or more, preferably 3.5 or more, more preferably 4.0 or more, and even more preferably 4.5 or more.

4. 3. The polyamide 56 fiber according to claim 1 or 2, the polyamide 56 draw-textured yarn has a fineness of 40 to 60 dtex; and / or The polyamide 56 draw textured yarn has a breaking strength of 3.5 to 5.5 cN / dtex, preferably 3.8 to 5.0 cN / dtex, more preferably 4.0 to 4.7 cN / dtex, and even more preferably 4.3 to 4.5 cN / dtex; and / or The polyamide 56 draw textured yarn has an elongation at break of 33 to 36%; and / or The polyamide 56 stretch-textured yarn has a crystallinity of 60% or more, preferably 63% or more, more preferably 66% or more, and even more preferably 68% or more; and / or The polyamide 56 stretch-textured yarn has an orientation degree of 60% or more, preferably 65% ​​or more, more preferably 70% or more, and even more preferably 73% or more; and / or The polyamide 56 fiber is characterized in that the polyamide 56 stretch-processed yarn has a dye uniformity (gray scale) of grade 3 or higher, preferably grade 3.5 or higher, more preferably grade 4.0 or higher, and even more preferably grade 4.5 or higher.

5. The polyamide 56 fiber according to claim 1 or 2, characterized in that the polyamide 56 stretch-textured yarn has a breaking strength of 3.5 to 5.5 cN / dtex, a crystallinity of 60 to 80%, or an orientation degree of 60 to 90%.

6. A process for the manufacture of polyamide 56 pre-oriented yarn according to any one of claims 1 to 3, characterized in that said process comprises the following steps: (1) polymerizing 1,5-pentanediamine and adipic acid to form a polyamide 56 melt or heating a polyamide 56 resin to a molten state in a screw to form a polyamide 56 melt, said polyamide 56 resin having an oligomer content of 1.2 wt% or less, a moisture content of 600-900 ppm, and a number average molecular weight of 18,000-22,000; (2) conveying the polyamide 56 melt through a pipe to a spinning pot, precisely metering the melt with a metering pump, and then injecting it into a spinning assembly and extruding it through a spinneret orifice; (3) Cooling, spin finishing, drawing and winding the extruded as-spun fibers to obtain said polyamide 56 pre-oriented yarn.

7. 7. The process of claim 6, In step (1), the polyamide 56 resin has a relative viscosity of 2.4 to 2.8, preferably 2.5 to 2.7; the polyamide 56 resin has an oligomer content of 0.8 wt.% or less; and / or the polyamide 56 resin has a number average molecular weight of 18,000 to 20,000, or a molecular weight distribution of 1.0 to 2.0, and preferably 1.2 to 1.8; and / or 10. The process according to claim 1, wherein the screw is heated in four zones; wherein the temperature in the first zone is 245-260°C, preferably 250-255°C; the temperature in the second zone is 260-275°C, and preferably 265-270°C; the temperature in the third zone is 275-285°C, preferably 278-283°C, and the temperature in the fourth zone is 280-285°C, preferably 282-284°C.

8. 7. The process of claim 6, In step (2), the temperature of the pot is 275-285°C, preferably 280-283°C; the pressure of the assembly is 13-20 MPa, preferably 15-18 MPa; and / or In step (3), the cooling comprises cooling by side air blow or cross air blow, preferably cooling by cross air blow; the air speed is preferably 0.2-0.6 m / s, more preferably 0.3-0.5 m / s; and / or the air temperature is 18-25° C., preferably 20-23° C., more preferably 21-22° C.; and / or the spin finish is done with an oil roll; the oil pick-up is 0.2-0.8 wt.%, preferably 0.3-0.7 wt.%, more preferably 0.4-0.5 wt.%; and / or A process characterized in that the winding speed is between 4000 and 5500 m / min, preferably between 4300 and 5000 m / min, more preferably between 4,500 and 4,800 m / min.

9. 6. A process for producing polyamide 56 draw textured yarn according to any one of claims 1, 2, 4 or 5, said process comprising the steps of: a) directing the polyamide 56 pre-oriented yarn by a guide to a first roller; conveying it through a twist stopper and hot drawing the pre-oriented yarn in a first hot box; b) cooling and setting the pre-oriented yarn on a cooling plate, transporting it through a false twister, a second roller, and an interlacing device, and spin-finishing it with an oil roll; and c) winding the pre-oriented yarn with a winding overfeed of 2 to 8% to obtain a polyamide 56 stretch-textured yarn; The hot stretch ratio is 1.2 to 1.3; The pressure of the compressed air in the intertwining device is 0.6 to 0.8 MPa; and A process characterised in that the winding speed is between 400 and 700 m / min.

10. 10. The process of claim 9, The hot stretching temperature is 150 to 220°C, preferably 160 to 200°C, more preferably 170 to 180°C; and / or the speed ratio D / Y of the false twisting machine is between 1.3 and 2.2, preferably between 1.5 and 2.0, more preferably between 1.7 and 1.8; and / or a winding speed of 500 to 600 m / min; and / or A process characterized in that the winding overfeed is between 3 and 6%, preferably between 4 and 5%.

11. Use of the polyamide 56 fibers according to any one of claims 1 to 5 in knitted or woven fabrics.

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