Polyamide drawn false-twisted yarn as well as preparation method and application thereof

Abstract

The invention discloses a polyamide drawn false-twisted yarn and a preparation method and application thereof. And the melting point of the polyamide drawn false-twisted yarn is 258-279 DEG C. The polyamide drawn false-twisted yarn has the advantages of being high in melting point and good in heat resistance, the melting point of the polyamide drawn false-twisted yarn is 258-279 DEG C and is far higher than that of existing polyamide 6 fibers, polyamide 56 fibers and polyamide 66 fibers, and the high temperature resistance is better. The polyamide drawn false-twisted yarn has the characteristics of good mechanical property, good dimensional stability, excellent elasticity, low water absorption, good dyeing property and high fastness, and can be applied to the fields of knitted and woven fabrics, carpet yarns, blended yarns, monofilaments and industrial yarns, in particular to the fields of knitted and woven fabrics.

Description

Technical Field

[0001] The invention relates to the technical field of polyamide materials, and in particular to a polyamide drawn false-twisted yarn and a preparation method and application thereof. Background Art

[0002] Polyamide fiber is one of the earliest synthetic fibers put into industrial production in the world, and plays a pivotal role in the field of synthetic fibers. There are many types of polyamide fibers, and the most widely used and industrially produced ones are polyamide 6 and polyamide 66. The main applications involve: socks, lace underwear, corsets, sports underwear, wedding dresses, casual jackets, sportswear, raincoats, assault jackets, quick-drying clothes, winter clothing, outdoor tents, sleeping bags, mountaineering bags and other fields; while industrial yarns are widely used in fields such as cords, transmission belts, hoses, ropes, fishing nets, tires, parachutes and so on.

[0003] Bio-based polyamide 56 uses bio-based pentamethylenediamine as the monomer raw material. The carbon emissions per unit weight of bio-based polyamide 56 are significantly lower than those of nylon 66 and nylon 6 of the same weight. The application and promotion of bio-based polyamide 56 will play a positive role in improving my country's dependence on foreign imports of key materials, and is of great significance for solving the sustainable development of fossil resource dependence and low-carbon emission reduction. Bio-based polyamide 56 material has excellent mechanical properties, moisture absorption and quick drying, skin affinity, wear resistance, good softness, and low-temperature easy dyeing characteristics. At present, it has broad application prospects in the fields of civil filaments, staple fibers, industrial yarns, continuous bulked filaments, monofilaments, etc.

[0004] The melting points of nylon 6, nylon 66, and polyamide 56 are approximately 220°C, 260°C, and 254°C, respectively. Currently, there is no relevant research and report on the preparation of a polyamide drawn false-twisted yarn with high melting point, heat resistance, good dimensional stability, low water absorption, good dyeing performance, and high fastness, and its downstream applications. Summary of the invention

[0005] A first aspect of the present invention provides a polyamide drawn false twisted yarn, wherein the melting point of the polyamide drawn false twisted yarn is 258-279°C.

[0006] The polyamide drawn false twisted yarn of the invention has a higher melting point and good high temperature resistance.

[0007] In one embodiment, the melting point of the polyamide drawn false twisted yarn is 263-279°C, further 266-275°C.

[0008] In one embodiment, the polyamide drawn false-twisted yarn has a fineness of 10-250 dtex, further 20-200 dtex, further 20-150 dtex, further 20-80 dtex.

[0009] The polyamide drawn false twisted yarn of the invention has good mechanical properties and better strength and toughness.

[0010] In one embodiment, the breaking strength of the polyamide drawn false twisted yarn is 3.0-5.5 cN / dtex, further 3.4-5.0 cN / dtex; further 3.7-4.6 cN / dtex.

[0011] In one embodiment, the elongation at break of the polyamide drawn false-twisted yarn is 20%-50%, further 25%-35%, further 25%-28%.

[0012] The polyamide drawn false twisted yarn of the invention has good cohesion, and the fiber has good bulkiness and elasticity.

[0013] In one embodiment, the crimp shrinkage of the polyamide drawn false twisted yarn is 38%-60%, further 42%-60%, further 49%-60%.

[0014] In one embodiment, the curl stability of the polyamide drawn false twisted yarn is 55%-90%, further 60%-85%, further 62%-75%.

[0015] The polyamide drawn false twisted yarn of the invention has good structural stability and a high degree of heat setting. When the fiber encounters a hot and humid environment during processing and wearing, the fiber has stable dimensions and is not easily deformed.

[0016] In one embodiment, the boiling water shrinkage of the polyamide drawn false twisted yarn is 1.5%-5.0%, further 1.5%-3.5%.

[0017] In one embodiment, the moisture regain of the polyamide drawn false-twisted yarn is ≤4.0%, further ≤3.7%, further ≤3.5%, further ≤3.3%.

[0018] The polyamide drawn false twisted yarn of the invention has good dyeing performance and high color fastness.

[0019] In one embodiment, the polyamide drawn false twisted yarn has a dyeing uniformity (gray card) of ≥4.0, further ≥4.5, further ≥4.7, further ≥5.

[0020] In one embodiment, the dyeing AAA ratio of the polyamide drawn false twisted yarn is ≥90%, further ≥94%, further ≥96%.

[0021] In one embodiment, the polyamide drawn false twisted yarn has a soap fastness of: fading fastness of ≥4.0, further ≥4.5, further ≥5.0; staining fastness of ≥4.0, further ≥4.5, further ≥5.0.

[0022] In one embodiment, the polyamide drawn false twisted yarn is a PA56T drawn false twisted yarn, and the raw material includes PA56T resin.

[0023] In one embodiment, the molar ratio of the structural units corresponding to adipic acid, terephthalic acid, and pentamethylenediamine in the PA56T resin is (80-65):(20-35):100, further (75-65):(25-35):100, and further (70-65):(30-35):100.

[0024] In one embodiment, the PA56T resin contains additives, and the additives include any one of sodium hypophosphite, calcium hypophosphite, phosphorous acid, antioxidant 1010, and antioxidant 1097, or a combination of two or more thereof, and further include any one of sodium hypophosphite, calcium hypophosphite, and antioxidant 1010, or a combination of two or more thereof.

[0025] In one embodiment, the PA56T resin contains additives in an amount of 10-800 ppm, further 10-200 ppm, further 55-150 ppm; and / or,

[0026] In one embodiment, the melting point of the PA56T resin is 258-279°C, further 263-279°C, further 266-275°C.

[0027] In one embodiment, the relative viscosity of the PA56T resin is 2.2-2.9, further 2.4-2.85.

[0028] In one embodiment, the amino content of the PA56T resin is 30-80 mmol / kg, further 35-70 mmol / kg, further 40-60 mmol / kg.

[0029] In one embodiment, the water content of the PA56T resin is 500 ppm or less, further 250 ppm or less, and further 125 ppm or less.

[0030] The second aspect of the present invention is to provide a method for preparing polyamide drawn false-twisted yarn.

[0031] The preparation method comprises:

[0032] 1) drying and heating the polyamide resin to a molten state to form a polyamide melt;

[0033] 2) The polyamide melt is transported to the spinning manifold, accurately metered by a metering pump, injected into the spinning assembly, and extruded from the spinneret holes to form primary fibers;

[0034] 3) Cooling, oiling and winding the spun fibers to obtain pre-oriented fibers;

[0035] 4) The pre-oriented yarn is stretched through a twist stopper, a first roller, a hot box, cooled and shaped, and then passed through a false twister, a second roller, a network device, a third roller, oiling treatment, and winding treatment to obtain a polyamide drawn false twist yarn.

[0036] In one embodiment, the polyamide resin in step 1) is PA56T resin. The PA56T resin has the same definition as described above.

[0037] In one embodiment, the drying temperature in step 1) is 70-160° C., further 80-130° C.; the drying time is 10-40 h, further 14-26 h.

[0038] In one embodiment, the heating in step 1) is carried out by a screw, wherein the temperature of zone 1 is 250-280°C, further 255-275°C; the temperature of zone 2 is 260-290°C, further 265-287°C; the temperature of zone 3 is 270-300°C, further 275-298°C; the temperature of zone 4 is 270-310°C, further 275-305°C.

[0039] In one embodiment, a monomer suction device is provided below the spinneret in step 2).

[0040] In one embodiment, in step 2), the spinning box temperature is 280-310°C, further 290-302°C.

[0041] In one embodiment, in step 2), the spinning assembly pressure is 10-30 MPa, further 10-18 MPa.

[0042] In one embodiment, the wind speed for cooling in step 3) is 0.4-0.6 m / s, further 0.42-0.50 m / s; the wind temperature is 16-22° C.; and the wind humidity is 70%-95%, further 75%-90%.

[0043] In one embodiment, the oiling rate in step 3) is 0.4%-0.6%, further 0.45%-0.5%.

[0044] In one embodiment, in step 3), the winding speed is 4000-5500 m / min, further 4200-5000 m / min, further 4300-5000 m / min.

[0045] In one embodiment, in step 4), the stretching ratio of the hot box stretching treatment is 1.1-1.4, further 1.2-1.3; the temperature of the hot box stretching treatment is 160-220°C, further 185-220°C, further 185-215°C.

[0046] In one embodiment, the speed ratio D / Y of the false twister in step 4) is (1.5-2.2):1, further (1.7-2.2):1, further (1.8-2.0):1.

[0047] In one embodiment, the spacing of the false twister in step 4) is 0.5-0.8 mm, further 0.6-0.75 mm.

[0048] In one embodiment, in step 4), the online tension T1 of the false twister is 10-25 cN, further 15-25 cN, and the online tension T2 of the false twister is 0.85-1.1 times, further 0.85-1.05 times, further 0.85-1.0 times, further 0.85-0.97 times of T1.

[0049] In one embodiment, the oil loading rate in step 4) is 2.0%-2.7wt%.

[0050] In one embodiment, the winding speed of the winding process in step 4) is 400-800 m / min, further 500-700 m / min.

[0051] The third aspect of the present invention is that the polyamide drawn false twisted yarn is applied to the fields of knitting and woven fabrics, carpet yarns, blended yarns, monofilaments, industrial yarns, and further to the fields of knitting and woven fabrics.

[0052] The beneficial effects that can be achieved by adopting the technical solution of the present invention include:

[0053] First, the polyamide drawn false twisted yarn of the present invention has the characteristics of high melting point and good heat resistance. The melting point of the polyamide drawn false twisted yarn is 258-279°C, which is much higher than the melting point of the current polyamide 6, polyamide 56 and polyamide 66 fibers, and has better high temperature resistance.

[0054] Second, the polyamide drawn false twisted yarn of the present invention has the characteristics of good mechanical properties, good dimensional stability, excellent elasticity, low water absorption, good dyeing performance and high fastness.

[0055] Thirdly, the polyamide drawn false twisted yarn of the present invention can be applied to the fields of knitted and woven fabrics, carpet yarns, blended yarns, monofilaments, and industrial yarns, especially the fields of knitted and woven fabrics. DETAILED DESCRIPTION

[0056] Test method:

[0057] (1) Fineness: measured in accordance with GB / T 14343.

[0058] (2) Breaking strength and breaking elongation: measured in accordance with GB / T 14344-2008.

[0059] (3) Relative viscosity: The relative viscosity is measured by the concentrated sulfuric acid method using an Ubbelohde viscometer, and the steps are as follows: accurately weigh 0.5±0.0002 g of the dried sample, add 50 mL of concentrated sulfuric acid (96%) to dissolve, and measure and record the flow time t0 of the concentrated sulfuric acid and the flow time t0 of the sample solution in a 25°C constant temperature water bath. The relative viscosity calculation formula is: relative viscosity VN=t / t0.

[0060] (4) Amino acid content: determined by automatic titrator.

[0061] (5) Water content: Determined by Karl Fischer titrator.

[0062] (6) Moisture regain: The washed fiber is placed in an oven in a loose state for drying, and the dried fiber sample is placed in the standard atmosphere specified in GB / T6529 for adjustment and balance. The sample after washing and moisture adjustment is then subjected to moisture regain measurement. The moisture regain measurement method is carried out in accordance with GB / T6503, where the drying temperature of the oven is 105°C and the drying time is 1h.

[0063] (7) Curling performance

[0064] The test was carried out in accordance with GB / T6506-2017 “Test method for shrinkage performance of synthetic fiber textured yarn”.

[0065] Curl shrinkage = ((L1-L2) / L1) × 100%;

[0066] Curl stability = ((L3-L1) / (L1-L2)) × 100%;

[0067] L1: The fiber length is measured after the fiber is subjected to a tension of 0.2 cN / dtex for 10 seconds;

[0068] L2: The fiber length measured after the fiber is subjected to a tension of 0.001 cN / dtex for 10 min;

[0070] L3: The fiber length is measured after the fiber is subjected to a tension of 1.0 cN / dtex for 10 seconds.

[0071] (8) Boiling water shrinkage: measured in accordance with GB / 6505.

[0072] (9) Dyeing uniformity (grey card) / grade: in accordance with FZ / T 50008 test method for dyeing uniformity of nylon filament.

[0073] (10) Dyeing AAA rate: Dyeing AAA rate = ((weight of fibers with dyeing uniformity reaching level 5.0) / total weight of all dyed fibers) × 100%.

[0074] (11)Fading fastness and staining fastness: measured in accordance with the national standard GB / T 3921.1-1997.

[0075] Example 1 (Specification 44dtex / 36f)

[0076] Preparation method of polyamide drawn false twisted yarn:

[0077] 1) drying and heating the polyamide resin to a molten state to form a polyamide melt;

[0078] 2) The polyamide melt is transported to the spinning manifold through a melt pipe, accurately metered by a metering pump, and then injected into the spinning assembly to be extruded from the spinneret holes to form primary fibers, wherein a monomer suction device is provided below the spinneret;

[0079] 3) Cooling, oiling and winding the spun fibers to obtain pre-oriented fibers;

[0080] 4) The pre-oriented yarn is stretched through a twist stopper, a first roller, a hot box, cooled and shaped, and then passed through a false twister, a second roller, a network device, a third roller, oiling treatment, and winding treatment to obtain a polyamide drawn false twist yarn.

[0081] In step 1), the polyamide resin is PA56T resin, and the molar ratio of the structural units corresponding to adipic acid, terephthalic acid, and pentamethylenediamine is 80:20:100. The polyamide resin contains an additive, sodium hypophosphite, with a content of 30 ppm; the melting point of the polyamide resin is 260° C., the relative viscosity is 2.6, and the amino content is 55 mmol / kg.

[0082] In step 1), the drying temperature is 100° C., the drying time is 30 h, and the water content of the polyamide resin after drying is 150 ppm.

[0083] The heating in step 1) is carried out by a screw, wherein the temperature of zone 1 is 260°C, the temperature of zone 2 is 270°C, the temperature of zone 3 is 280°C, and the temperature of zone 4 is 290°C.

[0084] In step 2), the spinning box temperature is 285° C. and the spinning assembly pressure is 15 MPa.

[0085] The cooling wind speed in step 3) is 0.45 m / s; the wind temperature is 19° C.; and the wind humidity is 85%.

[0086] In step 3), the oiling rate is 0.48%.

[0087] In step 3), the winding speed is 4200 m / min.

[0088] In step 4), the stretching ratio of the hot box stretching treatment is 1.25, and the temperature of the hot box stretching treatment is 180°C.

[0089] In step 4), the false twister speed ratio D / Y is 1.7:1. The false twister spacing is 0.5 mm. The inlet tension T1 of the false twister is 22 cN, and the outlet tension T2 of the false twister is 20 cN.

[0090] In step 4), the oil loading rate is 2.4 wt%.

[0091] In step 4), the winding speed of the winding process is 600 m / min.

[0092] Example 2 (Specification 44dtex / 36f)

[0093] Preparation method of polyamide drawn false twisted yarn:

[0094] 1) drying and heating the polyamide resin to a molten state to form a polyamide melt;

[0095] 2) The polyamide melt is transported to the spinning manifold through a melt pipe, accurately metered by a metering pump, and then injected into the spinning assembly to be extruded from the spinneret holes to form primary fibers, wherein a monomer suction device is provided below the spinneret;

[0096] 3) Cooling, oiling and winding the spun fibers to obtain pre-oriented fibers;

[0097] 4) The pre-oriented yarn is stretched through a twist stopper, a first roller, a hot box, cooled and shaped, and then passed through a false twister, a second roller, a network device, a third roller, oiling treatment, and winding treatment to obtain a polyamide drawn false twist yarn.

[0098] In step 1), the polyamide resin is PA56T resin, and the molar ratio of the structural units corresponding to adipic acid, terephthalic acid, and pentamethylenediamine is 75:25:100. The polyamide resin contains an additive, calcium hypophosphite, with a content of 50 ppm. The melting point of the polyamide resin is 264° C., the relative viscosity is 2.7, and the amino content is 50 mmol / kg.

[0099] In step 1), the drying temperature is 110° C., the drying time is 26 h, and the water content of the polyamide resin after drying is 140 ppm.

[0100] The heating in step 1) is carried out by a screw, wherein the temperature of zone 1 is 265°C, the temperature of zone 2 is 275°C, the temperature of zone 3 is 285°C, and the temperature of zone 4 is 295°C.

[0101] In step 2), the spinning box temperature is 288° C. and the spinning assembly pressure is 17 MPa.

[0102] The cooling wind speed in step 3) is 0.49 m / s, the wind temperature is 18° C., and the wind humidity is 80%.

[0103] In step 3), the oiling rate is 0.47%.

[0104] In step 3), the winding speed is 4300 m / min.

[0105] In step 4), the stretching ratio of the hot box stretching treatment is 1.28, and the temperature of the hot box stretching treatment is 190°C.

[0106] In step 4), the false twister speed ratio D / Y is 1.8:1, the false twister spacing is 0.6 mm, the inlet false twister online tension T1 is 20 cN, and the outlet false twister online tension T2 is 18.5 cN.

[0107] In step 4), the oil loading rate is 2.6 wt %.

[0108] In step 4), the winding speed of the winding process is 700 m / min.

[0109] Example 3 (Specification 44dtex / 36f)

[0110] Preparation method of polyamide drawn false twisted yarn:

[0111] 1) drying and heating the polyamide resin to a molten state to form a polyamide melt;

[0112] 2) The polyamide melt is transported to the spinning manifold through a melt pipe, accurately metered by a metering pump, and then injected into the spinning assembly to be extruded from the spinneret holes to form primary fibers, wherein a monomer suction device is provided below the spinneret;

[0113] 3) Cooling, oiling and winding the spun fibers to obtain pre-oriented fibers;

[0114] 4) The pre-oriented yarn is stretched through a twist stopper, a first roller, a hot box, cooled and shaped, and then passed through a false twister, a second roller, a network device, a third roller, oiling treatment, and winding treatment to obtain a polyamide drawn false twist yarn.

[0115] In step 1), the polyamide resin is PA56T resin, and the molar ratio of the structural units corresponding to adipic acid, terephthalic acid, and pentamethylenediamine is 70:30:100. The polyamide resin contains an additive, sodium hypophosphite, with a content of 80 ppm; the melting point of the polyamide resin is 269° C., the relative viscosity is 2.8, and the amino content is 48 mmol / kg.

[0116] In step 1), the drying temperature is 120° C., the drying time is 23 h, and the water content of the polyamide resin after drying is 100 ppm.

[0117] The heating in step 1) is carried out by a screw, wherein the temperature of zone 1 is 270°C, the temperature of zone 2 is 280°C, the temperature of zone 3 is 290°C, and the temperature of zone 4 is 295°C.

[0118] In step 2), the spinning box temperature is 293° C. and the spinning assembly pressure is 14 MPa.

[0119] The cooling wind speed in step 3) is 0.45 m / s, the wind temperature is 19° C. and the wind humidity is 85%.

[0120] In step 3), the oiling rate is 0.45%.

[0121] In step 3), the winding speed is 4500 m / min.

[0122] In step 4), the stretching ratio of the hot box stretching treatment is 1.25, and the temperature of the hot box stretching treatment is 200°C.

[0123] In step 4), the false twister speed ratio D / Y is 1.8:1, the false twister spacing is 0.65 mm, the inlet tension T1 of the false twister is 20.8 cN, and the outlet tension T2 of the false twister is 19.8 cN.

[0124] In step 4), the oil loading rate is 2.5 wt%.

[0125] The winding speed of the winding process in step 4) is 500m / min.

[0126] Embodiment 4 (Specification 44dtex / 36f)

[0127] Preparation method of polyamide drawn false twisted yarn:

[0128] 1) drying and heating the polyamide resin to a molten state to form a polyamide melt;

[0129] 2) The polyamide melt is transported to the spinning manifold through a melt pipe, accurately metered by a metering pump, and then injected into the spinning assembly to be extruded from the spinneret holes to form primary fibers, wherein a monomer suction device is provided below the spinneret;

[0130] 3) Cooling, oiling and winding the spun fibers to obtain pre-oriented fibers;

[0131] 4) The pre-oriented yarn is stretched through a twist stopper, a first roller, a hot box, cooled and shaped, and then passed through a false twister, a second roller, a network device, a third roller, oiling treatment, and winding treatment to obtain a polyamide drawn false twist yarn.

[0132] In step 1), the polyamide resin is PA56T resin, and the molar ratio of the structural units corresponding to adipic acid, terephthalic acid, and pentamethylenediamine is 65:35:100. The polyamide resin contains an additive antioxidant 1010, the content of which is 60 ppm. The melting point of the polyamide resin is 275° C., the relative viscosity is 2.85, and the amino content is 46 mmol / kg.

[0133] In step 1), the drying temperature is 130° C., the drying time is 20 h, and the water content of the polyamide resin after drying is 100 ppm.

[0134] The heating in step 1) is carried out by a screw, wherein the temperature of zone 1 is 270°C, the temperature of zone 2 is 285°C, the temperature of zone 3 is 295°C, and the temperature of zone 4 is 300°C.

[0135] In step 2), the spinning box temperature is 295° C. and the spinning assembly pressure is 12 MPa.

[0136] The cooling wind speed in step 3) is 0.43 m / s, the wind temperature is 20° C., and the wind humidity is 85%.

[0137] In step 3), the oiling rate is 0.46%.

[0138] In step 3), the winding speed is 4400 m / min.

[0139] In step 4), the stretching ratio of the hot box stretching treatment is 1.27, and the temperature of the hot box stretching treatment is 210°C.

[0140] In step 4), the false twister speed ratio D / Y is 1.9:1, the false twister spacing is 0.7 mm, the inlet false twister online tension T1 is 18.4 cN, and the outlet false twister online tension T2 is 17.4 cN.

[0141] In step 4), the oil loading rate is 2.4 wt%.

[0142] The winding speed of the winding process in step 4) is 600m / min.

[0143] Example 5 (Specification 44dtex / 36f)

[0144] Preparation method of polyamide drawn false twisted yarn:

[0145] The polyamide drawn false twisted yarn was prepared by the same process as in Example 1, except that the molar ratio of the structural units corresponding to adipic acid, terephthalic acid and pentamethylenediamine in the PA56T resin was 80:20:100. The additive in the resin was sodium hypophosphite with a content of 80 ppm, the melting point of the resin was 261° C., the relative viscosity was 2.6, and the amino content was 53 mmol / kg.

[0146] Example 6 (Specification 44dtex / 36f)

[0147] Preparation method of polyamide drawn false twisted yarn:

[0148] The polyamide drawn false twisted yarn was prepared by the same process as in Example 1, except that the stretching multiple of the hot box stretching treatment was 1.3 and the temperature of the hot box stretching treatment was 210°C.

[0149] Example 7 (Specification 44dtex / 36f)

[0150] Preparation method of polyamide drawn false twisted yarn:

[0151] The polyamide drawn false-twisted yarn was prepared by the same process as in Example 1, except that the speed ratio D / Y of the false twister was 2.0:1.

[0152] Comparative Example 1 (Specification 44dtex / 36f)

[0153] Preparation method of polyamide drawn false twisted yarn:

[0154] The polyamide drawn false twisted yarn was prepared by the same process as in Example 1, except that the molar ratio of the structural units corresponding to adipic acid, terephthalic acid and pentamethylenediamine in the PA56T resin was 80:20:100. The additive content in the resin was 0 ppm, the melting point of the resin was 259°C, the relative viscosity was 2.6, and the amino content was 55 mmol / kg.

[0155] Comparative Example 2 (Specification 44dtex / 36f)

[0156] Preparation method of polyamide drawn false twisted yarn:

[0157] The polyamide drawn false twisted yarn was prepared by the same process as in Example 1, except that the drying temperature in step (1) was 80° C., the drying time was 20 h, and the water content of the polyamide resin after drying was 600 ppm.

[0158] Comparative Example 3 (Specification 44dtex / 36f)

[0159] Preparation method of polyamide drawn false twisted yarn:

[0160] The polyamide drawn false twisted yarn was prepared by the same process as in Example 1, except that the molar ratio of the structural units corresponding to adipic acid, terephthalic acid and pentamethylenediamine in the PA56T resin was 80:20:100. The additive was sodium hypophosphite, and the content was 8 ppm. The melting point of the resin was 261°C, the relative viscosity was 2.0, and the amino content was 57 mmol / kg.

[0161] Comparative Example 4 (Specification 44dtex / 36f)

[0162] Preparation method of polyamide drawn false twisted yarn:

[0163] The polyamide drawn false twisted yarn was prepared by the same process as in Example 1, except that:

[0164] The polyamide resin is polyamide 56, with a melting point of 254° C. and a relative viscosity of 2.7. The additive in the resin is sodium hypophosphite with a content of 30 ppm. The amino content of the resin is 50 mmol / kg.

[0165] In step 1), the drying temperature is 100° C., the drying time is 20 h, and the water content of the polyamide resin after drying is 220 ppm.

[0166] The heating in step 1) is carried out in a screw extruder, with the temperature of zone 1 being 275°C, the temperature of zone 2 being 285°C, the temperature of zone 3 being 288°C, and the temperature of zone 4 being 290°C.

[0167] In step 2), the temperature of the spinning box is 285° C. and the pressure of the spinning assembly is 11 MPa.

[0168] Comparative Example 5 (Specification 44dtex / 36f)

[0169] Preparation method of polyamide drawn false twisted yarn:

[0170] The polyamide drawn false-twisted yarn was prepared by the same process as in Example 1, except that the spacing of the false-twisters was 0.45 mm.

[0171] Comparative Example 6 (Specification 44dtex / 36f)

[0172] Preparation method of polyamide drawn false twisted yarn:

[0173] The polyamide drawn false-twisted yarn was prepared by the same process as in Example 1, except that the online tension T1 entering the false twister was 22 cN, and the online tension T2 exiting the false twister was 12 cN.

[0174] The performance test results of polyamide drawn false twisted yarn are shown in Tables 1 and 2.

[0175] Table 1

[0176]

[0177] Table 2

[0178]

[0179] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements 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 polyamide drawn false twisted yarn, characterized in that: The melting point of polyamide drawn false twisted yarn is 258-279℃.

2. The polyamide drawn false twisted yarn according to claim 1, characterized in that: The melting point of the polyamide drawn false twisted yarn is 263-279° C., further 266-275° C.; and / or, The polyamide drawn false twisted yarn has a fineness of 10-250 dtex, further 20-200 dtex, further 20-150 dtex, further 20-80 dtex; and / or, The breaking strength of the polyamide drawn false twisted yarn is 3.0-5.5 cN / dtex, further 3.4-5.0 cN / dtex, further 3.7-4.6 cN / dtex; and / or, The elongation at break of the polyamide drawn false twisted yarn is 20%-50%, further 25%-35%, further 25%-28%; and / or, The boiling water shrinkage of the polyamide drawn false twisted yarn is 1.5%-5.0%, further 1.5%-3.5%; and / or, The moisture regain of the polyamide drawn false twisted yarn is ≤4.0%, further ≤3.7%, further ≤3.5%, further ≤3.3%.

3. The polyamide drawn false twisted yarn according to claim 1, characterized in that: The crimp shrinkage of the polyamide drawn false twisted yarn is 38%-60%, further 42%-60%, further 49%-60%; and / or, The curl stability of the polyamide drawn false twisted yarn is 55%-90%, further 60%-85%, further 62%-75%; and / or, The polyamide drawn false twisted yarn has a dyeing uniformity (gray card) of ≥4.0, further ≥4.5, further ≥4.7, further ≥5; and / or, The dyeing AAA rate of the polyamide drawn false twisted yarn is ≥90%, further ≥94%, further ≥96%; and / or, The soap washing fastness of the polyamide drawn false twisted yarn is: fading fastness is ≥ grade 4.0, further ≥ grade 4.5, further ≥ grade 5.0; staining fastness is ≥ grade 4.0, further ≥ grade 4.5, further ≥ grade 5.

0.

4. The polyamide drawn false twisted yarn according to any one of claims 1 to 3, characterized in that: The polyamide drawn false twisted yarn is a PA56T drawn false twisted yarn, and the raw material includes PA56T resin, preferably: The molar ratio of the structural units corresponding to adipic acid, terephthalic acid and pentamethylenediamine in the PA56T resin is (80-65): (20-35): 100, further (75-65): (25-35): 100, further (70-65): (30-35): 100; and / or, The PA56T resin contains additives, and the additives include any one of sodium hypophosphite, calcium hypophosphite, phosphorous acid, antioxidant 1010, and antioxidant 1097, or a combination of two or more thereof, and further include any one of sodium hypophosphite, calcium hypophosphite, and antioxidant 1010, or a combination of two or more thereof; and / or, The content of the additive in the PA56T resin is 10-800 ppm, further 10-200 ppm, further 55-150 ppm; and / or, The melting point of the PA56T resin is 258-279°C, further 263-279°C, further 266-275°C; and / or, The relative viscosity of the PA56T resin is 2.2-2.9, further 2.4-2.85; and / or, The amino content of the PA56T resin is 30-80 mmol / kg, further 35-70 mmol / kg, further 40-60 mmol / kg; and / or, The water content of the PA56T resin is 500 ppm or less, further 250 ppm or less, and further 125 ppm or less.

5. A method for preparing polyamide drawn false twisted yarn, characterized in that: include: 1) drying and heating the polyamide resin to a molten state to form a polyamide melt; 2) The polyamide melt is transported to the spinning manifold, accurately metered by a metering pump, injected into the spinning assembly, and extruded from the spinneret holes to form primary fibers; 3) Cooling, oiling and winding the spun fibers to obtain pre-oriented fibers; 4) The pre-oriented yarn is stretched through a twist stopper, a first roller, a hot box, cooled and shaped, and then passed through a false twister, a second roller, a network device, a third roller, oiling treatment, and winding treatment to obtain a polyamide drawn false twist yarn.

6. The method for preparing polyamide drawn false twisted yarn according to claim 5, characterized in that: The polyamide resin in step 1) is PA56T resin; and / or, In step 1), the drying temperature is 70-160° C., further 80-130° C.; the drying time is 10-40 hours, further 14-26 hours; and / or, The heating in step 1) is carried out by a screw, wherein the temperature of zone 1 is 250-280°C, further 255-275°C; the temperature of zone 2 is 260-290°C, further 265-287°C; the temperature of zone 3 is 270-300°C, further 275-298°C; the temperature of zone 4 is 270-310°C, further 275-305°C.

7. The method for preparing polyamide drawn false twisted yarn according to claim 5, characterized in that: In step 2), a monomer suction device is arranged below the spinneret; and / or, In step 2), the spinning box temperature is 280-310° C., further 290-302° C.; and / or, In step 2), the spinning assembly pressure is 10-30 MPa, further 10-18 MPa.

8. The method for preparing polyamide drawn false twisted yarn according to claim 5, characterized in that: In step 3), the wind speed for cooling is 0.4-0.6 m / s, further 0.42-0.50 m / s; the wind temperature is 16-22° C.; the wind humidity is 70%-95%, further 75%-90%; and / or, In step 3), the oiling rate is 0.4%-0.6%, further 0.45%-0.5%; and / or, In step 3), the winding speed is 4000-5500 m / min, further 4200-5000 m / min, further 4300-5000 m / min.

9. The method for preparing polyamide drawn false twisted yarn according to claim 5, characterized in that: In step 4), the stretching ratio of the hot box stretching treatment is 1.1-1.4, further 1.2-1.3; the temperature of the hot box stretching treatment is 160-220°C, further 185-220°C, further 185-215°C; and / or, The false twister speed ratio D / Y in step 4) is (1.5-2.2):1, further (1.7-2.2):1, further (1.8-2.0):1; and / or, The false twister spacing in step 4) is 0.5-0.8 mm, further 0.6-0.75 mm; and / or, In step 4), the online tension T1 of the false twister is 10-25 cN, further 15-25 cN, and the online tension T2 of the false twister is 0.85-1.1 times, further 0.85-1.05 times, further 0.85-1.0 times, further 0.85-0.97 times of T1; and / or, In step 4), the oiling rate is 2.0%-2.7wt%; and / or, The winding speed of the winding process in step 4) is 400-800 m / min, further 500-700 m / min.

10. A polyamide drawn false twisted yarn according to any one of claims 1 to 9, applied in the fields of knitting and woven fabrics, carpet yarns, blended yarns, monofilaments, industrial yarns, and further in the fields of knitting and woven fabrics.

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