Polyamide self-crimping elastic fiber as well as preparation method and application thereof

Abstract

The invention discloses a polyamide self-crimping elastic fiber as well as a preparation method and application thereof. The fiber comprises two parallel materials, the first material is a polyamide 56 / 6 copolymer, and the second material comprises but is not limited to one or more polyamide materials of polyamide 56, polyamide 6 and polyamide 66; the mass ratio of the first material to the second material is (35-65): (65-35); in the polyamide 56 / 6 copolymer, caprolactam accounts for 2.5-9.5% of the total mass of synthetic raw materials of the polyamide 56 / 6 copolymer. The raw material of the polyamide self-crimping elastic fiber provided by the invention is a bio-based material, so that carbon emission can be effectively reduced, and the polyamide self-crimping elastic fiber is environment-friendly; the polyamide self-curling elastic fiber is soft in hand feeling, good in hygroscopicity, good in wear resistance and good in wearability, and can be widely applied to medium-elasticity and micro-elasticity fabrics.

Description

Technical Field

[0001] The invention belongs to the technical field of polyamide fibers and relates to a polyamide self-curling elastic fiber and a preparation method and application thereof. Background Art

[0002] Self-curling elastic fiber, also known as parallel composite elastic fiber, is a parallel composite fiber obtained by melt spinning two polymers with good compatibility but large difference in thermal shrinkage according to a certain ratio. Due to the different thermal shrinkage properties of the two components after drawing and shaping, different shrinkage effects appear during the heat treatment process. The two components are relatively compatible, so during the heat treatment process, the component with a larger shrinkage rate will restrain each other with the component with a smaller shrinkage rate, thus forming a three-dimensional curled structure. In addition to the large difference in thermal shrinkage and good compatibility between the two raw materials, in the spinning process, the fluidity of the two components can be adjusted by matching the viscosity of the raw materials, regulating parameters such as temperature and moisture, and thus regulating the three-dimensional structural morphology of the elastic fiber. This curled fiber has different degrees of elasticity and elasticity like a spring, and has a curling elasticity similar to wool. This three-dimensional spiral curl is different from the curling obtained by conventional thermoplastic fibers through mechanical means of physical pressure and heating. This curling belongs to "self-curling". Compared with mechanical processing curling, self-curling fibers have better elasticity and more durable and stable curling. At present, the main type of bicomponent parallel elastic fibers are polyester. However, as people's demand for comfortable fabrics continues to increase, the requirements for softness, comfort and excellent moisture absorption performance of fabrics are getting higher and higher. Therefore, compared with polyester, polyamide materials show better moisture absorption and wear resistance, so the development of polyamide fibers for elastic fabrics has a broader application prospect.

[0003] Therefore, it is of great significance to develop a self-curling elastic fiber with better moisture absorption, higher strength and better wear resistance for elastic fabrics. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides a polyamide self-curling elastic fiber and a preparation method and application thereof. The polyamide self-curling elastic fiber has a unique three-dimensional curling structure, excellent elastic recovery performance, good elastic stability, and can give the fabric good elasticity. The raw materials of the polyamide self-curling elastic fiber provided by the present invention can be derived from bio-based materials, which can effectively reduce carbon emissions and be environmentally friendly; and the polyamide self-curling elastic fiber itself has a soft feel, good hygroscopicity, good wear resistance, and good wearing performance, and can be widely used in medium elastic and slightly elastic fabrics.

[0005] The present invention solves the above technical problems through the following technical solutions.

[0006] The present invention provides a polyamide self-curling elastic fiber, which comprises two parallel materials, wherein the first material is a polyamide 56 / 6 copolymer, and the second material comprises but is not limited to one or more polyamide materials selected from polyamide 56, polyamide 6 and polyamide 66;

[0007] Wherein, the mass ratio of the first material to the second material is (35-65): (65-35);

[0008] In the polyamide 56 / 6 copolymer, the mass percentage of the raw material caprolactam in the total mass of the synthetic raw materials of the polyamide 56 / 6 copolymer is 2.5-9.5%.

[0009] In the present invention, in the polyamide 56 / 6 copolymer, the mass percentage of the raw material caprolactam to the total mass of the synthetic raw materials of the polyamide 56 / 6 copolymer is, for example, 2.5%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 9.5%, preferably 3-9%.

[0010] In the present invention, the proportion of structural units in the polyamide 56 / 6 copolymer is adjusted to make the polyamide 56 / 6 copolymer have a high shrinkage rate. The present invention improves the curling performance of the polyamide self-curling elastic fiber by using the polyamide 56 / 6 copolymer with a high shrinkage rate as the first material and matching it with the second material with a low shrinkage rate.

[0011] In the present invention, preferably, the mass ratio of the first material to the second material is (45-55):(55-45).

[0012] In the present invention, the polyamide 56 / 6 copolymer generally refers to a polymer obtained by copolymerizing synthetic raw materials including 1,5-pentanediamine, adipic acid and caprolactam. The raw materials pentamethylenediamine and adipic acid can be prepared from bio-based raw materials by fermentation or enzyme conversion. The preparation of pentamethylenediamine and adipic acid by fermentation or enzyme conversion is beneficial to the sustainable development of the ecological environment.

[0013] In the present invention, the polyamide 56 / 6 copolymer contains the following three structural units:

[0014]

[0015] Among them, the structural unit (I) is a unit formed from pentamethylenediamine, the structural unit (II) is a unit formed from adipic acid, and the structural unit (III) is a unit formed from caprolactam.

[0016] In some specific embodiments, the melting point of the polyamide 56 / 6 copolymer is 180-260°C, such as 240°C, 250°C or 252°C, preferably 190-250°C, and more preferably 200-240°C.

[0017] In some specific embodiments, the terminal amino group content of the polyamide 56 / 6 copolymer is 30-65 mmol / kg, preferably 40-60 mmol / kg, more preferably 45-55 mmol / kg, such as 48 mmol / kg, 49.5 mmol / kg or 63 mmol / kg.

[0018] In some specific embodiments, the oligomer content in the polyamide 56 / 6 copolymer is ≤1.5wt%, such as 0.4wt%, 0.7wt% or 1.1wt%, preferably ≤0.8wt%, more preferably ≤0.6wt%. The oligomer is generally a polymer with a molecular weight of 500-3500g / mol produced by polycondensation of monomers.

[0019] In some specific embodiments, the water content of the polyamide 56 / 6 copolymer is 50-1300 ppm, preferably 200-1000 ppm, more preferably 300-800 ppm, such as 400-700 ppm, such as 410 ppm, 480 ppm, or 470 ppm.

[0020] In some specific embodiments, the relative viscosity of the polyamide 56 / 6 copolymer 96 wt % sulfuric acid is 2.0-3.5, preferably 2.1-3.3, more preferably 2.3-3.0, such as 2.63, 2.51 or 2.68.

[0021] In the present invention, preferably, the synthetic raw materials of the polyamide 56 / 6 copolymer also include other comonomers and / or additives. "Other comonomers" generally refer to other monomers involved in copolymerization in the synthetic raw materials of the polyamide 56 / 6 copolymer except pentamethylenediamine, adipic acid and caprolactam.

[0022] Among them, preferably, the other comonomers include one or more of aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, ethylenediamine, hexamethylenediamine, cyclohexanediamine, benzylenediamine, 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, p-aminomethylbenzoic acid, caprolactam and ω-laurolactam.

[0023] Preferably, the other comonomers account for 0.001-10% of the total mass of the synthetic raw materials of the polyamide 56 / 6 copolymer.

[0024] In some specific embodiments, the second material can be polyamide 56, polyamide 6, or polyamide 66.

[0025] In some specific embodiments, the relative viscosity of 96 wt % sulfuric acid of the second material is 2.0-4, preferably 2.2-3.6, more preferably 2.4-3.2, such as 2.69 or 2.54.

[0026] In some specific embodiments, the moisture content of the second material is 50-1300 ppm, preferably 200-1000 ppm, more preferably 300-800 ppm, further preferably 400-700 ppm, such as 434 ppm, 450 ppm or 467 ppm.

[0027] In some specific embodiments, the linear density of the polyamide self-curling elastic fiber is 15-280 dtex, preferably 20-200 dtex, and more preferably 30-100 dtex, for example, 40 dtex, 70.4 dtex, 70.6 dtex, 70.8 dtex, 70.9 dtex, 71.0 dtex, 71.1 dtex, 71.2 dtex, 71.3 dtex, 71.4 dtex, 71.5 dtex, 72 dtex, 76.2 dtex, 78.4 dtex or 80.1 dtex.

[0028] In some specific embodiments, the number of single fibers in the polyamide self-crimping elastic fiber is 10-100f, preferably 35-70f, such as 36f, 48f or 68f, wherein the number of single fibers is generally consistent with the number of holes in the spinneret.

[0029] In some specific embodiments, the linear density (dpf) of a single fiber in the polyamide self-crimping elastic fiber may be less than 5, preferably less than 3, more preferably less than 2, such as 1.94, 1.46 or 1.03. The dpf number is generally obtained by dividing the linear density by the number of spinneret holes.

[0030] In some specific embodiments, the breaking strength of the polyamide self-curling elastic fiber is 2.5-7.0 cN / dtex, preferably 3.5-6 cN / dtex, such as 4-5 cN / dtex.

[0031] In some specific embodiments, the elongation at break of the polyamide self-curling elastic fiber is 25-100%, preferably 35-70%, such as 42-55%.

[0032] In some specific embodiments, the initial modulus of the polyamide self-crimping elastic fiber is 20-60 cN / dtex, preferably 25-55 cN / dtex, such as 30-50 cN / dtex.

[0033] In some specific embodiments, the moisture regain of the polyamide self-curling elastic fiber is 1.0-6.0%, preferably 1.5-5.5%, and more preferably 1.8-5.3%.

[0034] In some specific embodiments, the boiling water shrinkage of the polyamide self-curling elastic fiber is 1.5-50%, preferably 5-30%, and more preferably 11-16%.

[0035] In some specific embodiments, the curl shrinkage rate of the polyamide self-curling elastic fiber is 35-90%, preferably 50-80%, and more preferably 70-76%.

[0036] In some specific embodiments, the curl modulus of the polyamide self-crimping elastic fiber is 25-60%, preferably 30-50%, and more preferably 39-43%.

[0037] In some specific embodiments, the curling stability of the polyamide self-curling elastic fiber is ≥81%, preferably ≥90%, and more preferably ≥92%.

[0038] In some specific embodiments, the curling elongation of the polyamide self-crimping elastic fiber before heat treatment is ≤65%, preferably ≤40%, and more preferably ≤30%.

[0039] In some specific embodiments, the curling elongation of the polyamide self-curling elastic fiber after heat treatment is ≥150%, preferably ≥300%, and more preferably ≥400%.

[0040] The present invention also provides a method for preparing the above-mentioned polyamide self-curling elastic fiber, which comprises the following steps:

[0041] S1, the first material and the second material are melted and spun together to form primary yarn;

[0042] S2 pre-treats and draws the spun yarn to obtain the polyamide self-curling elastic fiber.

[0043] In S1, the melting is generally performed in a screw extruder.

[0044] In S1, the first material is generally melted in a first screw extruder, and the first screw extruder preferably includes the following five temperature zones:

[0045] The temperature of zone 1 is 180-240°C, for example, 200°C, 210°C, 220°C or 230°C;

[0046] The temperature of the second zone is 200-250°C, for example, 210°C, 220°C, 230°C, 240°C or 250°C;

[0047] The temperature of the third zone is 210-275°C, such as 225°C, 245°C, 255°C, 260°C, 265°C or 275°C;

[0048] The temperature of the fourth zone is 220-280°C, for example, 245°C, 260°C, 265°C, 270°C, 275°C or 280°C;

[0049] The temperature of zone five is 230-280°C, for example, 255°C, 270°C, 275°C or 280°C.

[0050] In S1, the second material is generally melted in a second screw extruder, and the second screw extruder preferably includes the following five temperature zones:

[0051] The temperature of the first zone is 180-260°C, for example, 200°C, 220°C, 230°C, 235°C or 250°C;

[0052] The temperature of the second zone is 220-270°C, for example, 230°C, 245°C, 250°C or 265°C;

[0053] The temperature of the third zone is 230-280°C, for example, 240°C, 250°C, 270°C or 275°C;

[0054] The temperature of the fourth zone is 240-290°C, such as 255°C, 260°C, 265°C, or 280°C;

[0055] The temperature of zone five is 250-290°C, for example, 265°C, 278°C, 280°C, 285°C or 288°C.

[0056] In S1, the convergent spinning process is generally that the melt is transported to the composite spinning box through the melt pipe, extruded into the assembly through the metering pump, and then diverted through the composite spinneret, and bonded together at the composite spinneret to obtain the primary yarn.

[0057] The composite spinneret is generally a circular spinneret or an 8-shaped spinneret, preferably an 8-shaped spinneret. Preferably, the 8-shaped spinneret is provided with a plurality of spinneret holes, and the spinneret holes include two parallel circular ones.

[0058] The distance D between the centers of the two parallel circles may be 0.28-0.6 mm, preferably 0.3-0.55 mm, more preferably 0.32-0.45 mm, such as 0.36 mm, 0.38 mm, 0.4 mm or 0.42 mm.

[0059] The radius r of the two parallel circles may be 0.1-0.3 mm, preferably 0.12-0.28 mm, such as 0.14 mm or 0.18 mm.

[0060] The spinneret hole D-2r may be 0.03-0.14 mm, preferably 0.06-0.12 mm, such as 0.06, 0.08, 0.10 mm, 0.12 mm.

[0061] The radius r of the circular spinneret may be 0.1-0.3 mm, preferably 0.12-0.28 mm, such as 0.14 mm or 0.18 mm.

[0062] The number of holes of the composite spinneret may be 10-100f, preferably 35-70f, such as 36f, 48f or 68f.

[0063] In some specific embodiments, the composite spinneret may be ○-shaped, with a hole number of 68f and r of 0.14 mm.

[0064] In S1, the two melts before the convergent spinning are generally metered by a metering pump. The metering pump is generally a component for metering the melt during the melt spinning process.

[0065] In S1, in some specific embodiments, the temperature of the composite spinning beam during the convergent spinning process is 230-300°C, preferably 240-280°C, such as 260°C, 270°C, 278°C or 280°C.

[0066] In S1, in some specific embodiments, the pressure of the spinning assembly during the convergent spinning process is 12-30 MPa, preferably 14-25 MPa, such as 14 MPa, 15 MPa, 16 MPa or 17 MPa, and more preferably 15-20 MPa.

[0067] In S2, the pre-treatment generally includes cooling, oiling and pre-networking.

[0068] The cooling method may be conventional in the art, generally side-blowing cooling.

[0069] In some specific embodiments, the wind speed of the side blowing wind is 0.3-0.8 m / s, such as 0.4-0.7 m / s.

[0070] In some specific embodiments, the temperature of the cross-blown air is 18-26°C, such as 20°C, 22°C or 25°C.

[0071] In some specific embodiments, the humidity of the cross-blown air is 63-92%, such as 68%, 75% or 85%.

[0072] The oiling method may be conventional in the art, such as oiling with an oil nozzle.

[0073] In S2, the drawing is generally carried out in a two-step method or a one-step method, preferably a one-step method.

[0074] The two-step method generally involves first obtaining a pre-drawn yarn (POY), and then obtaining a drawn textured yarn DTY through false twisting, drawing and winding.

[0075] The preparation method of the pre-drawn POY yarn generally adopts winding forming by a winder. In some specific embodiments, the winding speed of the winder is 2800-5000 m / min, preferably 3500-4500 m / min, for example 4300 m / min.

[0076] In some specific embodiments, in the DTY process, the false twisting temperature is 120-190°C, preferably 140-180°C, such as 130°C, 135°C or 150°C.

[0077] In some specific embodiments, in the DTY process, the stretching ratio of the stretching is 1.0-2.5, preferably 1.2-2.0; for example, 1.28, 1.3, 1.32, 1.38 or 1.4.

[0078] In some specific embodiments, in the DTY process, the winding speed is 300-1000 m / min, preferably 500-700 m / min, such as 500 m / min, 550 m / min or 600 m / min.

[0079] The one-step method generally refers to the resin being melt extruded, cooled, oiled, pre-networked, and then directly subjected to hot roller drawing, main network, and winding to obtain fully drawn yarn FDY of parallel composite elastic fibers.

[0080] The hot roller drawing in the FDY process is preferably three pairs of hot rollers, namely HGR1, HGR2 and HGR3 (HGR is the Chinese name of heating drawing roller, which is the abbreviation of Heating godet roller).

[0081] The draft ratio in the FDY process may be conventional in the art.

[0082] In some specific embodiments, the draw ratio in the FDY process is 2.0-5.0, such as 3, 3.8 or 4.

[0083] The temperature of the HGR1 can be conventional in the art.

[0084] In some embodiments, the temperature of HGR1 is 50-150°C, preferably 80-120°C, such as 90°C or 100°C.

[0085] The temperature of the HGR2 can be conventional in the art.

[0086] In some embodiments, the temperature of HGR2 is 120-180°C, preferably 140-160°C, such as 150°C.

[0087] The temperature of the HGR3 can be conventional in the art.

[0088] In some embodiments, the temperature of HGR3 is 50-150°C, preferably 80-130°C, such as 90°C or 100°C.

[0089] The winding method in the FDY process can be conventional in the art, generally by winding by a winder.

[0090] In some specific embodiments, the winding speed of the winder is 2800-5500 m / min, preferably 3300-4800 m / min, such as 4500 m / min.

[0091] The present invention also provides application of the polyamide self-curling elastic fiber in elastic fabrics.

[0092] The elastic fabric may be a medium-elastic or slightly-elastic fabric, such as stretch jeans, underwear, shirts, swimsuits, sports shirts, socks and other close-fitting fabrics.

[0093] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0094] The reagents and raw materials used in the present invention are commercially available.

[0095] The positive and progressive effects of the present invention are:

[0096] The raw materials of the polyamide self-curling elastic fiber of the present invention can be derived from bio-based materials, which can effectively reduce carbon emissions and is environmentally friendly.

[0097] The preparation process of the polyamide self-curling elastic fiber of the invention is short and easy to operate; the prepared fiber can be directly woven and dyed, etc., which can reduce the production cost and is suitable for industrial production.

[0098] The polyamide self-curling elastic fiber of the present invention not only has a three-dimensional curling structure, resulting in excellent fiber elasticity and elastic stability (excellent curling elongation and curling shrinkage), but also has good moisture absorption and quick drying properties (moisture regain is higher than 0.4% of polyester fiber), skin affinity and good softness (for example, lower modulus) on the basis of meeting the mechanical properties of clothing textiles, and has the excellent wear resistance of nylon fiber and good wearing performance, and can be widely used in medium-elastic and slightly elastic fabrics, for example, mainly used in close-fitting fabrics such as stretch jeans, underwear, shirts, swimsuits, sports shirts, socks, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0099] Figure 1 It is a structural diagram of the 8-shaped spinneret of Examples 1-13 and 15-16 of the present invention.

[0100] Figure 2 This is a microscope picture (magnified 50 times) of the cross section of the polyamide self-crimping elastic fiber obtained in Example 1 of the present invention.

[0101] Figure 3 This is a microscope picture (magnified 50 times) of the cross section of the polyamide self-crimped elastic fiber obtained in Example 14 of the present invention. DETAILED DESCRIPTION

[0102] The present invention is further described below by way of examples, but the present invention is not limited to the scope of the examples. The experimental methods in the following examples without specifying specific conditions are carried out according to conventional methods and conditions, or selected according to the product specifications.

[0103] The detection method of the performance parameters involved in the present invention is as follows:

[0104] 1) Linear density: The test method of linear density can refer to GB / T 14343-2008 Test method for linear density of chemical fiber filaments; use YG086 yarn length measuring instrument, the circumference of the yarn frame is (1.000±0.002)m. Collect the length and mass of each sample respectively, the length is obtained by multiplying the number of turns by the length of the yarn frame, and the sample is weighed after debugging in standard atmosphere, accurate to 1mg, and each sample is tested 10 times to calculate the average value.

[0105] 2) Breaking strength, elongation at break, modulus: The determination of breaking strength and elongation at break can refer to GB / T14344-2008 Test method for tensile properties of chemical fibers; apply 0.05±0.005cN / dtex pre-tension, holding distance 500mm, stretching speed 500mm / min, modulus = breaking strength corresponding to elongation at break of 1% × 100.

[0106] 3) Moisture regain: The determination method is: put the washed fiber into an oven in a loose state to dry, and then place the dried fiber sample in the standard atmosphere specified in GB / T6529 for adjustment and balance, and adjust the humidity for 2 hours. The sample after washing and humidity adjustment is subjected to moisture regain determination. The moisture regain determination method is implemented in accordance with GB / T6503, where the drying temperature of the oven is 105°C and the drying time is 1 hour.

[0107] 4) Boiling water shrinkage: refer to GB / T6505-2017 "Test method for thermal shrinkage of chemical fiber filaments (after treatment)".

[0108] S = ((L0-L1) / L0) × 100%;

[0109] S: boiling water shrinkage;

[0110] L0: length of the sample before heat treatment, in millimeters (mm);

[0111] L1: The length of the sample after heat treatment, in millimeters (mm).

[0112] 5) Curling performance

[0113] According to GB / T6506-2017 "Test method for shrinkage performance of synthetic fiber textured yarn".

[0114] Curl shrinkage = ((L1-L2) / L1) × 100%;

[0115] Crimp modulus = ((L1-L3) / L1) × 100%;

[0116] Curl stability = ((L4-L1) / (L1-L2)) × 100%;

[0117] L1: The fiber is subjected to a tension of 0.2 cN / dtex for 10 seconds, and the fiber length is measured; L2: The fiber is subjected to a tension of 0.001 cN / dtex for 10 minutes, and the fiber length is measured; L3: The fiber is subjected to a tension of 0.01 cN / dtex for 10 seconds, and the fiber length is measured; L4: The fiber is subjected to a tension of 1.0 cN / dtex for 10 seconds, and the fiber length is measured;

[0118] 6) Curl elongation

[0119] Curl elongation: The percentage ratio of the deformation length of the curled textured yarn from the natural state to the complete elimination of the curled structure under the action of tensile force to the fiber length in the natural state.

[0120] Curl elongation = (L1-L0) / L0×100%

[0121] L0: the length of the crimped textured yarn in its natural state;

[0122] L1: The length of the curled textured yarn when it is slowly stretched to a straight state under the action of tensile force (tension is 0.2 cN / dtex).

[0123] 7) Hand feel evaluation:

[0124] The subjective evaluation group evaluation method is adopted. The evaluation group consists of 24 people. They evaluate the softness and smoothness of each group of experimental samples. The evaluation group members rank the order by touching. Then the average result is calculated by statistical method. The hand feel is divided into four levels, level 1 is the worst - hard, level 2 is the second - harder, level 3 is better - softer, and level 4 is the best - soft.

[0125] The sources of raw materials involved in the present invention are as follows:

[0126] 1) In the following examples and comparative examples, polyamide 6, polyamide 66, and polyamide 56 were purchased from Cathay (Jinxiang) Biomaterials Co., Ltd., and polyethylene terephthalate and polytrimethylene terephthalate were purchased from Sinopec.

[0127] 2) In the following examples and comparative examples, the preparation method of the polyamide 56 / 6 copolymer comprises the following steps: 1,5-pentanediamine, adipic acid, caprolactam and water are uniformly mixed under nitrogen conditions, and a fluorescent whitening agent is added at the same time; wherein, polymers with different mass ratios are prepared by adjusting the mass proportion of caprolactam, and 1,5-pentanediamine, adipic acid and caprolactam are added, and the molar ratio of pentamethylenediamine to adipic acid is (1-1.08):1, and the mass percentage of caprolactam is 2. 5-9.5%; in addition, the fluorescent whitening agent accounts for 0.3wt% of the total mass of 1,5-pentanediamine, adipic acid and caprolactam; then the solution is heated, the pressure in the reaction system is raised to 0.25-2.3MPa, the air is exhausted, the pressure is maintained, and the pressure is reduced to reduce the pressure in the reaction system to a gauge pressure of 0-0.35MPa, and the vacuum is evacuated to a vacuum degree of -0.08--0.01MPa to obtain a polyamide melt; in the reaction process, the temperature of the reaction system is 0-0.35°C when the pressure is maintained.

[0128] Example 1

[0129] 1) The melts of polyamide 56 / 6 copolymer (mass percentage of caprolactam is 9%, melting point is 240°C, terminal amino group is 49.5 mmol / kg, oligomer is 1.1 wt%, relative viscosity is 2.68, and water content is 480 ppm) and polyamide 56 (relative viscosity is 2.69, and water content is 467 ppm) are respectively transported to the composite spinning manifold through melt pipes, and after entering the assembly, they are diverted by the composite spinneret and bonded together at the spinneret to form primary yarns.

[0130] The ratio of the two materials is controlled by adjusting the frequency of the metering pump. The first material, polyamide 56 / 6 copolymer, has a content of 50 wt%, and the second material, polyamide 56, has a content of 50 wt%.

[0131] Among them, the heating temperature settings of the five zones of the screw extruder corresponding to polyamide 56 / 6 are as follows: the temperature of zone 1 is 230°C, the temperature of zone 2 is 240°C, the temperature of zone 3 is 255°C, the temperature of zone 4 is 265°C, and the temperature of zone 5 is 275°C; the heating temperature settings of the five zones of the screw extruder corresponding to polyamide 56 are as follows: the temperature of zone 1 is 235°C, the temperature of zone 2 is 250°C, the temperature of zone 3 is 270°C, the temperature of zone 4 is 280°C, and the temperature of zone 5 is 280°C.

[0132] The melt passes through the spinneret of the spinning box (8-shaped, structured as Figure 1 As shown, the number of holes is 36f, D, r, and D-2r are 0.36mm, 0.14mm, and 0.08mm respectively) for extrusion, the temperature of the spinning manifold is 280°C, and the spinning assembly pressure of the spinning manifold is 16MPa.

[0133] 2) The spun yarn is subjected to side-blowing cooling, oiling with an oil nozzle, pre-interlacing, stretching by three pairs of hot rollers, heat setting, main interlacing, and finally winding by a winder to obtain a polyamide self-curling elastic fiber.

[0134] Cooling is carried out by side blowing, with a wind speed of 0.7m / s, a wind temperature of 25°C, and a humidity of 68%; the stretching process uses three pairs of hot rollers, the total stretching multiple is 3.8, the temperature of HGR1 is 90°C, the temperature of HGR2 is 160°C, the temperature of HGR3 is 90°C, and the winding speed is 4500m / min.

[0135] Figure 2 This is a cross-sectional view of the polyamide self-curling elastic fiber obtained in Example 1 of the present invention (magnified 50 times).

[0136] Example 2

[0137] The spinneret structure is 8-shaped, D, r, and D-2r are 0.38 mm, 0.14 mm, and 0.10 mm respectively, and the rest is the same as in Example 1.

[0138] Example 3

[0139] The spinneret structure is 8-shaped, D, r, and D-2r are 0.36 mm, 0.12 mm, and 0.12 mm respectively, and the rest is the same as in Example 1.

[0140] Example 4

[0141] The spinneret structure is 8-shaped, with 48f holes, and the rest is the same as in Example 1.

[0142] Example 5

[0143] The spinneret structure is 8-shaped, with 68f holes, and the rest is the same as in Example 1.

[0144] Example 6

[0145] Polyamide 56 / 6 copolymer (mass percentage of caprolactam is 3%, melting point is 252°C, terminal amino group is 63mmol / kg, oligomer is 0.4wt%, relative viscosity is 2.51, water content is 410ppm) is the first material, and the corresponding five-zone heating temperature of the screw extruder is set as follows: the temperature of zone 1 is 240°C, the temperature of zone 2 is 250°C, the temperature of zone 3 is 265°C, the temperature of zone 4 is 275°C, and the temperature of zone 5 is 280°C. Other spinning conditions are consistent with those in Example 5.

[0146] Example 7

[0147] Polyamide 56 / 6 copolymer (mass percentage of caprolactam is 5%, melting point is 250°C, terminal amino group is 48 mmol / kg, oligomer is 0.7wt%, relative viscosity is 2.63, and water content is 470ppm) is the first material, and the corresponding five-zone heating temperature settings of the screw extruder are as follows: the temperature of zone 1 is 230°C, the temperature of zone 2 is 250°C, the temperature of zone 3 is 275°C, the temperature of zone 4 is 280°C, and the temperature of zone 5 is 280°C. Other spinning conditions are consistent with those in Example 5.

[0148] Example 8

[0149] Polyamide 66 (relative viscosity of 2.54, water content of 450 ppm) is the second material, and the corresponding five-zone heating temperature of the screw extruder is set as follows: the temperature of zone 1 is 230° C., the temperature of zone 2 is 245° C., the temperature of zone 3 is 250° C., the temperature of zone 4 is 265° C., and the temperature of zone 5 is 278° C. Other spinning conditions are the same as those in Example 5.

[0150] Example 9

[0151] Polyamide 56 / 6 copolymer (mass percentage of caprolactam is 3%, melting point is 252°C, terminal amino group is 63 mmol / kg, oligomer is 0.4 wt%, relative viscosity is 2.51, and water content is 410 ppm) is the first material, and other spinning conditions are consistent with Example 8.

[0152] Example 10

[0153] Polyamide 56 / 6 copolymer (mass percentage of caprolactam is 9%, melting point is 240°C, terminal amino group is 49.5 mmol / kg, oligomer is 1.1wt%, relative viscosity is 2.68, and water content is 480 ppm) is the first material, and the corresponding five-zone heating temperature of the screw extruder is set as follows: the temperature of zone 1 is 210°C, the temperature of zone 2 is 230°C, the temperature of zone 3 is 245°C, the temperature of zone 4 is 260°C, and the temperature of zone 5 is 270°C; other spinning conditions are consistent with Example 8.

[0154] Embodiment 11

[0155] Polyamide 6 (relative viscosity of 2.54, moisture of 434 ppm) is the second material, and the corresponding five-zone heating temperature of the screw extruder is set as follows: the temperature of zone 1 is 220° C., the temperature of zone 2 is 230° C., the temperature of zone 3 is 240° C., the temperature of zone 4 is 255° C., and the temperature of zone 5 is 265° C. Other spinning conditions are the same as those in Example 8.

[0156] Example 12

[0157] Polyamide 56 / 6 copolymer (mass percentage of caprolactam is 3%, melting point is 252°C, terminal amino group is 63 mmol / kg, oligomer is 0.4 wt%, relative viscosity is 2.51, and water content is 410 ppm) is the first material, polyamide 6 is the second material, and other spinning conditions are consistent with Example 11.

[0158] Embodiment 13

[0159] Polyamide 56 / 6 copolymer (mass percentage of caprolactam is 9%, melting point is 240°C, terminal amino group is 49.5 mmol / kg, oligomer is 1.1wt%, relative viscosity is 2.68, and water content is 480 ppm) is the first material, and the corresponding five-zone heating temperature of the screw extruder is set as follows: the temperature of zone 1 is 220°C, the temperature of zone 2 is 240°C, the temperature of zone 3 is 255°C, the temperature of zone 4 is 265°C, and the temperature of zone 5 is 270°C; other spinning conditions are consistent with Example 11.

[0160] Embodiment 14

[0161] The spinneret (O type, number of holes 68f, r is 0.14mm), other conditions are the same as in Example 5, the structure of the obtained polyamide self-curling elastic fiber is shown in the figure Figure 3 shown.

[0162] Embodiment 15

[0163] The number of spinneret holes is 12f, and other conditions are the same as in Example 5.

[0164] Example 16

[0165] A spinneret (8-shaped, number of holes 68f, D, r, D-2r are 0.42 mm, 0.14 mm, 0.14 mm, respectively) and other conditions are the same as those in Example 5 to obtain polyamide self-curling elastic fibers.

[0166] Comparative Example 1

[0167] 1) Polyethylene terephthalate (PET, relative viscosity of 0.67, water content of 36 ppm) and polytrimethylene terephthalate (PTT, relative viscosity of 1.0, water content of 50 ppm) are melted separately and transported to the composite spinning manifold through a melt pipe. After entering the assembly, they are diverted by the composite spinneret and bonded together at the spinneret to form primary yarn.

[0168] The ratio of the two materials is controlled by adjusting the frequency of the metering pump, the PET content of the first material is 50wt%, and the PTT content of the second material is 50wt%.

[0169] Among them, the heating temperature settings of the five zones of the screw extruder corresponding to PET are as follows: the temperature of zone 1 is 250°C, the temperature of zone 2 is 265°C, the temperature of zone 3 is 275°C, the temperature of zone 4 is 280°C, and the temperature of zone 5 is 280°C; the heating temperature settings of the five zones of the screw extruder corresponding to PTT are as follows: the temperature of zone 1 is 250°C, the temperature of zone 2 is 265°C, the temperature of zone 3 is 275°C, the temperature of zone 4 is 280°C, and the temperature of zone 5 is 280°C.

[0170] The melt was extruded through a spinneret (8-shaped, number of holes 68f, D, r, D-2r 0.36mm, 0.14mm, 0.08mm respectively) of a spinning manifold. The temperature of the spinning manifold was 280°C, and the spinning assembly pressure of the spinning manifold was 17MPa.

[0171] 2) The raw silk is subjected to side-blowing cooling, oiling with an oil nozzle, pre-interlacing, drawing by three pairs of hot rollers, main interlacing, and finally winding by a winder to obtain parallel composite elastic fibers.

[0172] Cooling is carried out by side blowing, with a wind speed of 0.7m / s, a wind temperature of 25°C, and a humidity of 62%; the stretching process uses three pairs of hot rollers, the total stretching multiple is 3.5, the temperature of HGR1 is 75°C, the temperature of HGR2 is 140°C, the temperature of HGR3 is 90°C, and the winding speed is 4300m / min.

[0173] Comparative Example 2

[0174] The melts of polyamide 56 (relative viscosity of 2.69, moisture of 467ppm) and polyamide 6 (relative viscosity of 2.54, moisture of 434ppm) are respectively transported to the composite spinning box through melt pipes. After entering the assembly, they are diverted by the composite spinneret and bonded together at the spinneret to form primary yarns.

[0175] The ratio of the two materials is controlled by adjusting the frequency of the metering pump. The content of the first material, polyamide 56 copolymer, is 50wt%, and the content of the second material, polyamide 6, is 50wt%.

[0176] The heating temperature of the five zones of the screw extruder corresponding to polyamide 56 is set as follows: the temperature of zone 1 is 250°C, the temperature of zone 2 is 265°C, the temperature of zone 3 is 275°C, the temperature of zone 4 is 280°C, and the temperature of zone 5 is 280°C; the heating temperature of the five zones of the screw extruder corresponding to polyamide 6 is set as follows: the temperature of zone 1 is 200°C, the temperature of zone 2 is 210°C, the temperature of zone 3 is 225°C, the temperature of zone 4 is 245°C, and the temperature of zone 5 is 265°C. Other spinning conditions are consistent with those in Example 5.

[0177] Comparative Example 3

[0178] Polyamide 56 / 6 copolymer (mass percentage of caprolactam is 20%, melting point is 221°C, terminal amino group is 48mmol / kg, oligomer is 0.7wt%) is the first material, and polyamide 6 is the second material. The heating temperature of the five zones of the screw extruder corresponding to the polyamide 56 / 6 copolymer is set as follows: the temperature of the first zone is 200°C, the temperature of the second zone is 210°C, the temperature of the third zone is 225°C, the temperature of the fourth zone is 245°C, and the temperature of the fifth zone is 255°C; the relative viscosity of the 96wt% sulfuric acid of the polyamide 56 / 6 copolymer is 2.8, and the water content is 500ppm. Other spinning conditions are consistent with those in Example 11.

[0179] The obtained polyamide self-curling elastic fiber structure is as follows Figure 2 shown.

[0180] Comparative Example 4

[0181] Polyamide 56 / 6 copolymer (mass percentage of caprolactam is 2%, melting point is 253°C, terminal amino group is 61mmol / kg, oligomer is 0.5wt%) is the first material, and polyamide 6 is the second material. The heating temperature of the five zones of the screw extruder corresponding to the polyamide 56 / 6 copolymer is set as follows: the temperature of the first zone is 240°C, the temperature of the second zone is 255°C, the temperature of the third zone is 265°C, the temperature of the fourth zone is 275°C, and the temperature of the fifth zone is 280°C; the relative viscosity of the 96wt% sulfuric acid of the polyamide 56 / 6 copolymer is 2.8, and the water content is 268ppm. Other spinning conditions are consistent with those of Example 11.

[0182] Comparative Example 5

[0183] 1) Polyamide 56 / 6 copolymer (mass percentage of caprolactam is 10%, melting point is 238°C, terminal amino group is 50 mmol / kg, oligomer is 1.0wt%, relative viscosity is 2.69, and water content is 268ppm) is used as the first material, and the corresponding five-zone heating temperatures of the screw extruder are set as follows: the temperature of zone 1 is 200°C, the temperature of zone 2 is 210°C, the temperature of zone 3 is 225°C, the temperature of zone 4 is 245°C, and the temperature of zone 5 is 255°C. Other spinning conditions are consistent with Example 11.

[0184] The key parameters in Examples 1-16 and Comparative Examples 1-5 are listed in Table 1 as follows:

[0185] Table 1

[0186]

[0187]

[0188] Effect Example

[0189] The performance indicators of the self-curling elastic fibers obtained in Examples 1-16 and Comparative Examples 1-5 were tested, and the mechanical performance indicators of the fibers obtained by the test are shown in Table 2.

[0190] Table 2 Fiber mechanical properties in examples and comparative examples

[0191]

[0192] The curling properties and boiling water shrinkage of the obtained self-curling elastic fibers were tested, and the results are shown in Table 3. When testing the curling properties of the fibers, the obtained fibers were treated in 100°C water for 30 minutes and then dried. As can be seen from Table 3, the curling modulus (%) and curling stability (%) of the polyamide self-curling elastic fibers obtained in Examples 1-16 are generally better than those in Comparative Examples 1-5.

[0193] Table 3 Fiber curling and elastic properties in the examples and comparative examples

[0194]

Claims

1. A polyamide self-curling elastic fiber, characterized in that: The polyamide self-curling elastic fiber comprises two parallel materials, wherein the first material is a polyamide 56 / 6 copolymer, and the second material comprises but is not limited to one or more polyamide materials selected from polyamide 56, polyamide 6 and polyamide 66; Wherein, the mass ratio of the first material to the second material is (35-65): (65-35); In the polyamide 56 / 6 copolymer, the mass percentage of the raw material caprolactam in the total mass of the synthetic raw materials of the polyamide 56 / 6 copolymer is 2.5-9.5%.

2. The polyamide self-crimping elastic fiber according to claim 1, characterized in that: The polyamide self-crimping elastic fiber meets one or more of the following conditions: (1) In the polyamide 56 / 6 copolymer, the mass percentage of the raw material caprolactam to the total mass of the synthetic raw materials of the polyamide 56 / 6 copolymer is 3-9%; (2) The mass ratio of the first material to the second material is (45-55):(55-45); and, (3) The synthetic raw materials of the polyamide 56 / 6 copolymer further include other comonomers and / or additives in addition to pentamethylenediamine, adipic acid and caprolactam; Wherein, preferably, the other comonomers include one or more of aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, ethylenediamine, hexamethylenediamine, cyclohexanediamine, xylylenediamine, 6-aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, p-aminomethylbenzoic acid, caprolactam and ω-laurolactam; Preferably, the other comonomers account for 0.001-10% of the total mass of the synthetic raw materials of the polyamide 56 / 6 copolymer.

3. The polyamide self-crimping elastic fiber according to claim 1, characterized in that: The polyamide self-crimping elastic fiber meets one or more of the following conditions: (1) The melting point of the polyamide 56 / 6 copolymer is 180-260°C, preferably 190-250°C, and more preferably 200-240°C; (2) The terminal amino group content of the polyamide 56 / 6 copolymer is 30-65 mmol / kg, preferably 40-60 mmol / kg, and more preferably 45-55 mmol / kg; (3) The oligomer content of the polyamide 56 / 6 copolymer is ≤1.5wt%, preferably ≤0.8wt%, more preferably ≤0.6wt%; (4) The water content of the polyamide 56 / 6 copolymer is 50-1300 ppm, preferably 200-1000 ppm, more preferably 300-800 ppm; (5) The relative viscosity of the polyamide 56 / 6 copolymer in 96 wt% sulfuric acid is 2.0-3.5, preferably 2.1-3.3, more preferably 2.3-3.0; (6) The second material is polyamide 56, polyamide 6 or polyamide 66; (7) the relative viscosity of 96 wt % sulfuric acid of the second material is 2.0-4, preferably 2.2-3.6, more preferably 2.4-3.2; and, (8) The moisture content of the second material is 50-1300 ppm, preferably 200-1000 ppm, more preferably 300-800 ppm, and further preferably 400-700 ppm.

4. The polyamide self-crimping elastic fiber according to claim 1, characterized in that: The polyamide self-crimping elastic fiber meets one or more of the following conditions: (1) The linear density of the polyamide self-curling elastic fiber is 15-280 dtex; (2) The number of single fibers contained in the polyamide self-curling elastic fiber is 10-100f; (3) The linear density dpf of a single fiber in the polyamide self-curling elastic fiber is less than 5; (4) The breaking strength of the polyamide self-curling elastic fiber is 2.5-7.0 cN / dtex; (5) The elongation at break of the polyamide self-curling elastic fiber is 25-100%; (6) The initial modulus of the polyamide self-curling elastic fiber is 20-60 cN / dtex; (7) The moisture regain of the polyamide self-curling elastic fiber is 1.0-6.0%; (8) The boiling water shrinkage of the polyamide self-curling elastic fiber is 1.5-50%; (9) The curling shrinkage rate of the polyamide self-curling elastic fiber is 35-90%; (10) The curling modulus of the polyamide self-curling elastic fiber is 25-60%; (11) The curling stability of the polyamide self-curling elastic fiber is ≥ 81%; (12) The polyamide self-crimping elastic fiber has a crimping elongation of ≤65% before heat treatment; and (13) The curling elongation of the polyamide self-curling elastic fiber after heat treatment is ≥150%.

5. The polyamide self-crimping elastic fiber according to claim 4, characterized in that: The polyamide self-crimping elastic fiber meets one or more of the following conditions: (1) The linear density of the polyamide self-curling elastic fiber is 20-200 dtex, preferably 30-100 dtex; (2) The number of single fibers contained in the polyamide self-curling elastic fiber is 35-70f; (3) The linear density dpf of a single fiber in the polyamide self-curling elastic fiber is less than 3, preferably less than 2; (4) The breaking strength of the polyamide self-curling elastic fiber is 3.5-6 cN / dtex, for example 4-5 cN / dtex; (5) The elongation at break of the polyamide self-curling elastic fiber is 35-70%, for example, 42-55%; (6) The initial modulus of the polyamide self-curling elastic fiber is 25-55 cN / dtex, for example 30-50 cN / dtex; (7) The moisture regain of the polyamide self-curling elastic fiber is 1.5-5.5%, preferably 1.8-5.3%; (8) The boiling water shrinkage of the polyamide self-curling elastic fiber is 5-30%, preferably 11-16%; (9) The curling shrinkage rate of the polyamide self-curling elastic fiber is 50-80%, preferably 70-76%; (10) The curling modulus of the polyamide self-curling elastic fiber is 30-50%, preferably 39-43%; (11) The curling stability of the polyamide self-curling elastic fiber is ≥ 90%, preferably ≥ 92%; (12) The polyamide self-crimping elastic fiber has a crimping elongation of ≤40% before heat treatment, preferably ≤30%; and, (13) The curling elongation of the polyamide self-curling elastic fiber after heat treatment is ≥300%, preferably ≥400%.

6. A method for preparing the polyamide self-crimping elastic fiber according to any one of claims 1 to 5, characterized in that: It includes the following steps: S1, the first material and the second material are melted and spun together to form primary yarn; S2 pre-treats and draws the spun yarn to obtain the polyamide self-curling elastic fiber.

7. The method for preparing the polyamide self-crimping elastic fiber according to claim 6, characterized in that: The preparation method meets one or more of the following conditions: (1) In S1, the first material is melted in a first screw extruder, and the first screw extruder preferably includes the following five temperature zones: The temperature of zone 1 is 180-240℃; The temperature of zone 2 is 200-250℃; The temperature of zone 3 is 210-275℃; The temperature of zone 4 is 220-280℃; The temperature of zone 5 is 230-280℃; (2) In S1, the second material is melted in a second screw extruder, and the second screw extruder preferably includes the following five temperature zones: The temperature of zone 1 is 180-260℃; The temperature of zone 2 is 220-270℃; The temperature of zone 3 is 230-280℃; The temperature of zone 4 is 240-290℃; The temperature of zone 5 is 250-290℃; (3) In S1, the convergent spinning process is that the melt is transported to the composite spinning box through the melt pipe, extruded into the assembly through the metering pump, and then separated by the composite spinneret, and bonded together at the composite spinneret to obtain the primary filament; (4) In S1, the temperature of the composite spinning box during the converging spinning process is 230-300° C., preferably 240-280° C.; and, (5) In S1, the pressure of the spinning assembly during the convergent spinning process is 12-30 MPa, preferably 14-25 MPa, and more preferably 15-20 MPa.

8. The method for preparing the polyamide self-crimping elastic fiber according to claim 7, characterized in that: The preparation method satisfies (1) and / or (2) of the following conditions: (1) The composite spinneret adopts a circular spinneret or an 8-shaped spinneret; (2) The number of holes of the composite spinneret is 10-100f, preferably 35-70f.

9. The method for preparing the polyamide self-crimping elastic fiber according to claim 8, characterized in that: The preparation method satisfies (1) and / or (2) of the following conditions: (1) The 8-shaped spinneret is provided with a plurality of spinneret holes, wherein the spinneret holes include two parallel circular holes; The center distance D of the two parallel circles is preferably 0.28-0.6 mm, more preferably 0.3-0.55 mm, more preferably 0.32-0.45 mm; The radius r of the two parallel circles is preferably 0.1-0.3 mm, more preferably 0.12-0.28 mm; The spinneret hole D-2r is 0.03-0.14 mm; (2) The radius r of the circular spinneret is preferably 0.1-0.3 mm, more preferably 0.12-0.28 mm.

10. Use of the polyamide self-curling elastic fiber according to any one of claims 1 to 5 in elastic fabrics.

Images