Primary filaments, polyamide fibers and methods of making and using the same

Abstract

The application discloses a primary filament, a polyamide fiber and a preparation method and application thereof. The primary filament is manufactured by the following method: a spinning solution is formed into a primary filament through wet spinning; the viscosity of the spinning solution is not less than 1 Pa.s; the spinning solution comprises polyamide and a solvent; the polyamide contains at least one diamine unit and at least one diacid unit, the diacid unit contains at least one aliphatic diacid unit and at least one aromatic diacid unit, and the diamine unit contains at least one pentanediamine unit. The wet spinning process of the application can be applied to high-melting-point polyamide resin, is beneficial to industrialized scale production, and the prepared primary filament has good processability. The polyamide fiber prepared from the primary filament has excellent heat resistance, high strength and low shrinkage, and can be applied to various application scenarios.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fiber materials, in particular to a primary filament, a polyamide fiber and a preparation method and application thereof. BACKGROUND

[0002] Polyamide fiber is one of the earliest synthetic fibers to be put into industrial production in the world, and plays an important role in the field of synthetic fibers. There are many types of polyamide fibers, and the most widely used in industrial production and application at present are polyamide 6 and polyamide 66. The main applications involve: socks, lingerie, corset, sports underwear, wedding dress, casual jacket, sportswear, raincoat, combat clothing, quick-drying clothes, cold-weather clothing, outdoor tents, sleeping bags, mountaineering bags and other fields; and industrial yarns are widely used in fields such as curtain cord, transmission belt, hose, rope, fishing net, tire, parachute, etc.

[0003] Polyamide fibers are usually made by melt spinning method, but if the melting point of the polyamide resin itself is relatively high, close to the thermal decomposition temperature, the traditional melt spinning method will cause melt degradation, resulting in problems such as spinning silk flying, broken silk and poor mechanical properties of the fiber. Therefore, for polyamide resins with high melting point, in order to obtain high-performance polyamide fibers, a more suitable production process needs to be developed. SUMMARY

[0004] In order to overcome the defects such as melt degradation, spinning silk flying, broken silk and poor mechanical properties of the fiber caused by the fact that the melting point of the polyamide resin is relatively high and close to the thermal decomposition temperature when the polyamide fiber is made by the melt spinning method in the prior art, the present application provides a primary filament, a polyamide fiber and a preparation method and application thereof. The polyamide fiber prepared from the primary filament of the present application has the performance characteristics of heat resistance, high strength and low shrinkage, is widely used, and the manufacturing method can be suitable for high-melting-point polyamide resins, which is beneficial to industrialized scale-up production.

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

[0006] In a first aspect, the present application provides a primary filament, which is manufactured by the following method: forming a primary filament from a spinning solution by wet spinning;

[0007] The viscosity of the spinning solution is not less than 1 Pa.s.

[0008] The spinning solution comprises polyamide and solvent; the polyamide contains at least one diamine unit and at least one diacid unit, the diacid unit contains at least one aliphatic diacid unit and at least one aromatic diacid unit, and the diamine unit contains at least one pentanediamine unit.

[0009] Spinning solution

[0010] In the present application, the viscosity of the spinning solution is preferably 1-100 Pa.s, more preferably 15-50 Pa.s. The viscosity of the spinning solution in the present application is tested by rotation method, for example, according to the method of GB / T 10247-2008.

[0011] In some embodiments, the viscosity of the spinning solution is preferably 15-50 Pa.s, for example, 16.7 Pa.s, 19.5 Pa.s, 19.9 Pa.s, 21.6 Pa.s, 22.6 Pa.s, 24.2 Pa.s, 25.5 Pa.s, 27.6 Pa.s, 29.6 Pa.s, 32.4 Pa.s, 33.4 Pa.s, 34.2 Pa.s, 35.1 Pa.s, 35.5 Pa.s, 36.8 Pa.s, 40.8 Pa.s, 42.5 Pa.s, or 43.1 Pa.s.

[0012] In the present application, the concentration of the spinning solution can be 3%-70%, preferably 5%-55%, more preferably 10-50%, for example, 15%, 20%, 22%, 23%, 25%, 27%, 28%, 30%, 31%, 32%, 34%, 35%, 36%, 40%, 45%, or 48%, the percentage being the mass percentage of the polyamide in the spinning solution. If the content of polyamide in the spinning solution is lower than the above range, the viscosity of the spinning solution can be too low; if it exceeds the above range, the viscosity can be excessively increased, which is not conducive to spinning.

[0013] The present application does not have special limitations on the preparation method or reaction conditions of the spinning solution, and the polyamide and the solvent can be mixed at -10°C-100°C until the polyamide is dissolved, and the mixing time is not particularly limited.

[0014] Polyamide

[0015] In the present application, the molar ratio of the diamine unit to the diacid unit can be (0.9-1.2):1, preferably (0.95-1.1):1, for example, 1.05:1.

[0016] In the present application, the molar ratio of the aliphatic diacid unit to the aromatic diacid unit can be (10-50):(50-90), preferably (20-50):(50-75), for example, 50:50, 30:70, or 35:65.

[0017] In some embodiments, the molar percentage of the pentanediamine unit in the diamine unit is 20%-100%, preferably 20%-70%, for example, 50.25%.

[0018] In the present application, the diamine unit is derived from an aliphatic diamine, preferably butanediamine, pentanediamine, hexanediamine, heptanediamine, octanediamine, nonanediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, or a combination thereof, for example derived from pentanediamine and / or hexanediamine.

[0019] In some embodiments, the hexanediamine is 1,6-hexanediamine.

[0020] In some embodiments, the pentanediamine is 1,5-pentanediamine.

[0021] In some embodiments, the pentanediamine unit is derived from a bio-based pentanediamine, which refers to pentanediamine synthesized from glucose, lysine, or other compounds derived from biomass in the monomer synthesis process through enzymatic reaction, yeast reaction, or fermentation reaction, etc.

[0022] In some embodiments, the bio-based content of the bio-based pentanediamine can be determined by measuring the radioactive C14 content, for example, by the standard ASTM-D6866 method of the American Society for Testing Materials.

[0023] In the present application, the aliphatic diacid unit is derived from an aliphatic short-chain diacid and / or an aliphatic long-chain diacid.

[0024] In some embodiments, the aliphatic short-chain diacid includes oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, or a combination thereof, preferably adipic acid, for example 1,6-adipic acid.

[0025] In some embodiments, the aliphatic long-chain diacid includes nonanedioic acid, decanedioic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, or a combination thereof, preferably decanedioic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, or a combination thereof.

[0026] In some embodiments, the aliphatic diacid unit is derived from a combination of an aliphatic short-chain diacid, for example adipic acid, and an aliphatic long-chain diacid, for example selected from decanedioic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, or a combination thereof.

[0027] In the present application, the aromatic diacid unit is derived from an aromatic diacid and / or an aromatic diacid derivative, preferably phthalic acid and / or phthalic acid ester.

[0028] In some specific embodiments, the phthalic acid may be one or more of terephthalic acid, isophthalic acid and phthalic acid, for example, terephthalic acid.

[0029] In some specific embodiments, the phthalate may be terephthalate, preferably, the terephthalate is dimethyl terephthalate and / or diethyl terephthalate.

[0030] In some preferred embodiments, the diamine unit is derived from pentanediamine; the aliphatic diacid unit is derived from diacid and any one selected from sebacic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, and hexadecanoic acid; and the aromatic diacid unit is derived from terephthalic acid.

[0031] In some specific embodiments, the diamine unit is derived from pentamethylenediamine and hexamethylenediamine, the aliphatic diacid unit is derived from diacid, and the aromatic diacid unit is derived from terephthalic acid.

[0032] In some specific embodiments, the diamine unit is derived from 1,5-pentanediamine and 1,6-hexanediamine, the aliphatic diacid unit is derived from 1,6-adipic acid, and the aromatic diacid unit is derived from terephthalic acid.

[0033] In this invention, the polyamide can be represented as polyamide 5XY, or simply PA5XY, where "5" represents a pentanediamine unit, "X" represents other diamine units, and "Y" represents a diacid unit.

[0034] In some specific embodiments, the polyamide is a bio-based polyamide 5XY, which contains diamine units derived from bio-based pentanediamine, offering the advantage of a renewable source. Examples of bio-based polyamide 5XY include commercially available polyamides supplied by Cathay Biotech Inc. A series of materials, such as 6638、 6308 6300 6290 6635、 6631、 6632、 6520 5000 3600 3601 3100 3102, 3300 3500 2260 2262、 1273、 1251or 1320.

[0035] In some embodiments, the polyamide can have a relative viscosity of 1.2-6.0, preferably 2.0-5.2, such as 2.57, 2.73, 3.15, 3.20, 3.27, 3.34, 3.50, 4.20, 4.50, 5.00 or 5.20. The relative viscosity is determined by the Ubbelohde viscometer concentrated sulfuric acid (96% concentration) method.

[0036] In some embodiments, the polyamide can be subjected to a viscosity increasing treatment before use. The purpose of the viscosity increasing treatment is to make the viscosity of the polyamide meet the aforementioned requirements.

[0037] In some embodiments, the polyamide can have a melting point of 250-320°C, preferably 260-310°C, such as 267°C, 279°C, 275°C, 287°C, 289°C, 298°C or 300°C.

[0038] In the present application, the polyamide can further comprise an additive. The content of the additive can be selected according to the actual situation.

[0039] The additive can include a heat stabilizer, an antioxidant, a fluorescent whitening agent, a pigment, a dye, an anti-UV agent, a flame retardant, a flow modifier, an organic filler, an inorganic filler, a silica powder, a powder binder, a carbon nanotube or a combination thereof, such as a heat stabilizer and / or an antioxidant.

[0040] The heat stabilizer can be phosphoric acid, phosphorous acid, trimethyl phosphite, triphenyl phosphite, trimethyl phosphate, triphenyl phosphate, sodium hypophosphite, zinc hypophosphite, calcium hypophosphite, potassium hypophosphite or a combination thereof, such as sodium hypophosphite.

[0041] The antioxidant is selected from one or more of a hindered phenol antioxidant, a hindered amine antioxidant and a phosphite antioxidant;

[0042] The hindered phenol antioxidant can be commercially available, and preferably the hindered phenol antioxidant is selected from antioxidant 1098 and / or antioxidant 1010, such as antioxidant 1098.

[0043] The phosphite antioxidant can be commercially available, and preferably the phosphite antioxidant is selected from antioxidant 168 and / or antioxidant S9228.

[0044] Preferably, the antioxidant is selected from one or more of Antioxidant 168, Antioxidant 1098, Antioxidant 1010 and Antioxidant S9228.

[0045] In some embodiments, the polyamide contains sodium hypophosphite and Antioxidant 1098.

[0046] In the above embodiments, the content of sodium hypophosphite can be 0.03wt%, the percentage being the mass of sodium hypophosphite divided by the sum of the masses of the raw materials of the polyamide.

[0047] In the above embodiments, the content of Antioxidant 1098 can be 0.3wt%, the percentage being the mass of Antioxidant 1098 divided by the sum of the masses of the raw materials of the polyamide.

[0048] In some preferred embodiments, the polyamide is prepared by the following method: mixing monomers and water to obtain a polyamide salt solution, controlling the temperature and pressure, carrying out a polymerization reaction to obtain a melt, and then drawing and cutting the melt to obtain the polyamide; wherein the monomers include at least one diamine and at least one diacid, the diacid contains at least one aliphatic diacid and at least one aromatic diacid, and the diamine contains at least pentanediamine.

[0049] In some embodiments, the polyamide can be prepared by the following method:

[0050] S1, mixing monomers and water to prepare a polyamide salt solution, to obtain a polyamide salt aqueous solution with a concentration of 30-75wt%; wherein the monomers include at least one diamine and at least one diacid, the diacid contains at least one aliphatic diacid and at least one aromatic diacid, and the diamine contains at least pentanediamine;

[0051] S2, heating the polyamide salt aqueous solution to a temperature of 230-310℃ under a nitrogen or inert gas atmosphere, at a reaction pressure of 0.7-2.5MPa, for 60-180min; then exhaust to normal pressure while increasing the temperature to 260-340℃; vacuumize to reduce the pressure to -(0.02-0.08)MPa, and maintain for 0.1-120min, to obtain a melt, draw and cut the melt to obtain the polyamide.

[0052] Solvent

[0053] In the present application, the solvent can be a solvent that is conventional in the art and that can dissolve the polyamide, and for example can be dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), an aqueous sodium thiocyanate solution, an aqueous zinc chloride solution, nitric acid, sulfuric acid, formic acid, acetic acid, dichloromethane, benzene, toluene, xylene, methanol, ethanol, phenol, chloroform, and the like, which can be used alone or in a mixture of two or more, and can be used in a mixture with water.

[0054] In some embodiments, the solvent is formic acid, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, or N-methylpyrrolidone.

[0055] In some embodiments, when the solvent is used in a mixture with water, the solvent accounts for 50 to 99.99 wt% of the total mass of the solvent and water. The percentage of the solvent in the total mass of the solvent and water can be adjusted by dilution with water or concentration by evaporation.

[0056] Wet spinning

[0057] In the present application, the wet spinning can generally include the steps of jetting and coagulating the spinning solution as described above.

[0058] In some embodiments, the wet spinning includes the step of passing the spinning solution as described above through a spinneret into a coagulation bath. In some embodiments, the temperature of the spinning solution can be 5 to 100°C, preferably 10 to 80°C, more preferably 15 to 45°C, for example, 20°C, 25°C, 30°C, 35°C, or 40°C.

[0059] In some embodiments of the present application, the temperature of the spinning solution is 25°C, 40°C, 45°C, 50°C, 60°C, 65°C, 70°C, 75°C, or 80°C.

[0060] In some embodiments, the device for jetting can use a device that is conventional in the art, and the device for jetting can generally include a spinneret or a spinneret and a spinneret plate. When the device for jetting includes a spinneret and a spinneret plate, the spinneret is disposed on the spinneret plate.

[0061] In some embodiments, the number of holes of the spinneret plate can be 5 to 100,000 f, preferably 10 to 50,000 f, for example, 40 f, 50 f, 60 f, 80 f, 100 f, 300 f, or 500 f.

[0062] In some embodiments, the jetting speed of the jetting can be 0.1-6 m / min, preferably 1-3 m / min, for example 1.5 m / min, 1.61 m / min, 1.65 m / min, 1.71 m / min, 1.72 m / min, 1.82 m / min, 1.84 m / min, 1.85 m / min, 1.87 m / min, 1.89 m / min, 1.92 m / min, 1.95 m / min, 1.96 m / min, 2.05 m / min, 2.09 m / min, 2.31 m / min or 2.35 m / min.

[0063] In some embodiments, the jetting further comprises a step of degassing and filtering the spinning solution before the jetting.

[0064] In some embodiments, the degassing can be performed by conventional methods in the art, for example by vibration degassing or adding a defoaming agent.

[0065] In some embodiments, the filtering can be performed by conventional methods in the art, and the purpose of the filtering is to remove unreacted impurities, large colloidal particles, etc. in the solution to avoid blocking the jetting head and improve the spinning performance.

[0066] In some embodiments, the coagulation bath comprises water and / or a coagulant.

[0067] In some embodiments, the coagulant is preferably one or more of dimethylformamide, dimethylacetamide, dimethyl sulfoxide, N-methyl pyrrolidone, aqueous sodium thiocyanate, aqueous zinc chloride, nitric acid, sulfuric acid, formic acid, acetic acid, dichloromethane, benzene, toluene, xylene, methanol, ethanol, phenol and chloroform.

[0068] In some embodiments, the coagulation bath comprises water and a coagulant, wherein the concentration of the coagulant is 0.1%-55%, more preferably 0.1%-45%, for example 15%, 18%, 20%, 22%, 24%, 25%, 28% or 30%, and the percentage is the percentage of the solvent in the total volume of the coagulation bath.

[0069] In some embodiments, the coagulation bath comprises, for example, water and formic acid, water and DMF, water and DMAc, water and DMSO, or water and NMP.

[0070] In some embodiments, the temperature of the coagulation bath is 3-80°C, preferably 10-60°C, more preferably 15-45°C, for example 20°C, 25°C, 30°C, 35°C or 40°C.

[0071] In some embodiments, the nascent filaments have smooth fiber surfaces and porous core-sheath structures in cross section.

[0072] In a second aspect, the present application provides a method for preparing the as-spun fiber, comprising the following steps: forming the as-spun fiber by wet spinning a spinning solution; wherein the viscosity of the spinning solution is not less than 1 Pa.s; the spinning solution comprises a polyamide and a solvent; the polyamide comprises at least one diamine unit and at least one diacid unit, the diacid unit comprises at least one aliphatic diacid unit and at least one aromatic diacid unit, and the diamine unit comprises at least one pentanediamine unit.

[0073] wherein the spinning solution, the polyamide, the wet spinning and the like are as defined above.

[0074] In a third aspect, the present application provides a polyamide fiber, which is manufactured by drawing, washing, heat treating, oiling and winding the as-spun fiber as defined above.

[0075] In some embodiments, the draw ratio can be adjusted according to the actual fiber use, for example, the draw ratio is 1-20 times.

[0076] For fibers for general clothing, the draw ratio is 5-10 times, preferably 6-9 times.

[0077] For industrial or technical fibers, the draw ratio is 10-18 times, preferably 12-17 times.

[0078] In some embodiments, the draw ratio is, for example, 4.9 times, 5.2 times, 5.4 times, 5.7 times, 5.9 times, 6.1 times, 6.3 times, 6.4 times, 6.8 times, 6.9 times, 7.0 times, 7.1 times, 7.2 times, 7.5 times, 8.1 times, 8.6 times or 8.9 times.

[0079] In some embodiments, the drawing method of the drawing can be wet heat drawing or dry heat drawing, or a combination of wet heat drawing and dry heat drawing, without particular limitation.

[0080] In some embodiments, the temperature of the wet heat drawing is 20-95°C, preferably 25-85°C. For example, the temperature of the wet heat drawing is 70°C, 80°C, 85°C, 88°C, 90°C, 92°C or 93°C.

[0081] In some embodiments, the temperature of the dry heat drawing is 96-260°C, preferably 100-250°C. For example, the temperature of the dry heat drawing is 210°C, 220°C, 225°C, 230°C or 242°C.

[0082] In some embodiments, the drawing method of the drawing is a combination of wet heat drawing and dry heat drawing.

[0083] In some embodiments, the washing agent can be water or / and ethanol, and the purpose of the washing is to remove organic solvents and impurities attached to the surface of the fiber.

[0084] In some embodiments, the heat treatment includes drying and heat setting. The purpose of the drying is to remove excess water in the fiber. The purpose of the heat setting process is to eliminate the internal stress generated in the fiber during the stretching process, to allow the macromolecules to relax to a certain extent, to improve the deformation recovery ability of the fiber, and to maintain the state at the time of setting.

[0085] In some embodiments, the drying temperature can be 25-250°C, preferably 50-220°C, for example 100°C, 115°C or 120°C.

[0086] In some embodiments, the heat setting temperature can be 100-280°C, preferably 130-260°C, for example 140°C, 150°C, 160°C, 165°C, 168°C, 170°C, 175°C or 180°C.

[0087] In some embodiments, the heat setting can be carried out in a conventional manner in the art, preferably high-temperature high-pressure steam or a hot box.

[0088] In some embodiments, the oil concentration of the oiling can be 1%-5%, preferably 1.5%-3%, for example 1.70%, 1.72%, 1.79%, 1.80%, 1.85%, 1.90%, 2.00% or 2.15%, and the percentage is the mass percentage of the oil in the raw silk.

[0089] In some embodiments, the winding speed can be 10-1000 m / min, preferably 20-700 m / min, more preferably 30-500 m / min, for example 50 m / min, 80 m / min, 85 m / min, 86 m / min, 90 m / min, 98 m / min, 100 m / min, 105 m / min, 106 m / min, 110 m / min, 116 m / min or 120 m / min.

[0090] In some embodiments, the number of broken filaments of the polyamide fiber can be 0-6 times per 24 hours, preferably 0-4 times per 24 hours, more preferably 0-2 times per 24 hours, for example 0.2 times per 24 hours, 0.3 times per 24 hours, 0.5 times per 24 hours or 1 time per 24 hours.

[0091] In some embodiments, the polyamide fiber has a breaking strength of 2.0-20.0 cN / dtex, preferably 3.5-15.0 cN / dtex, more preferably 4.5-10.0 cN / dtex. The breaking strength is determined according to GB / T 14344-2008.

[0092] In some embodiments, the polyamide fiber has a breaking strength of 3.42 cN / dtex, 3.59 cN / dtex, 3.62 cN / dtex, 3.69 cN / dtex, 3.77 cN / dtex, 3.95 cN / dtex, 4.28 cN / dtex, 4.59 cN / dtex, 4.64 cN / dtex, 4.71 cN / dtex, 4.90 cN / dtex, 4.94 cN / dtex, 5.37 cN / dtex, 3.53 cN / dtex, 3.85 cN / dtex, 4.32 cN / dtex, 5.19 cN / dtex or 5.26 cN / dtex.

[0093] In some embodiments, the polyamide fiber has an elongation at break of 1-50%, preferably 3-40%, more preferably 5-30%. The elongation at break is determined according to GB / T 14344-2008.

[0094] In some embodiments of the present application, the polyamide fiber has an elongation at break of 32.63%, 34.74%, 34.81%, 35.93%, 36.10%, 36.43%, 36.50%, 36.68%, 37.52%, 37.68%, 37.73%, 38.80%, 38.93%, 39.20%, 39.37%, 39.53%, 40.94%, 41.20% or 43.50%.

[0095] In some embodiments, the polyamide fiber has an initial modulus of 20-80 cN / dtex, preferably 25-70 cN / dtex, more preferably 30-60 cN / dtex, such as 38.90 cN / dtex, 39.40 cN / dtex, 39.81 cN / dtex, 40.76 cN / dtex, 42.30 cN / dtex, 42.59 cN / dtex, 43.24 cN / dtex, 43.50 cN / dtex, 43.71 cN / dtex, 44.10 cN / dtex, 44.70 cN / dtex, 44.90 cN / dtex, 45.90 cN / dtex, 47.60 cN / dtex, 49.70 cN / dtex, 52.14 cN / dtex, or 54.43 cN / dtex. The initial modulus is determined according to GB / T 14344-2008.

[0096] In some embodiments, the polyamide fiber has a boiling water shrinkage of 3-11%, preferably 3-10%, more preferably 3-8%. The boiling water shrinkage is determined according to GB / 6505-2008 “Chemical fiber filament heat shrinkage test method”, and the specific calculation formula is as follows: boiling water shrinkage = ((length before heat treatment - length after heat treatment) / length before heat treatment) * 100%.

[0097] In some embodiments, the polyamide fiber has a boiling water shrinkage of 5.04%, 5.13%, 5.45%, 5.67%, 6.84%, 7.07%, 7.26%, 7.49%, 7.58%, 7.62%, 8.59%, 9.35%, 9.62%, 9.73%, 10.02%, 10.17%, 10.34%, 10.52%, or 10.95%.

[0098] In some embodiments, the polyamide fiber has a dry heat shrinkage of 1.0-7.0% at 177°C for 2 min, preferably 1.5-6.0%, more preferably 2.0-5.0%. The dry heat shrinkage is determined according to FZ / T50004, and the heat treatment temperature is 180°C.

[0099] In some embodiments, the polyamide fiber has a dry heat shrinkage of 2.27%, 2.45%, 2.93%, 2.97%, 3.67%, 3.93%, 4.10%, 4.29%, 4.31%, 4.38%, 5.24%, 6.03%, 6.42%, 6.56%, 6.75%, 6.98%, 7.16%, 7.09%, or 7.30% at 177°C for 2 min.

[0100] In some embodiments, the polyamide fiber has an orientation degree of 0.4-0.9, preferably 0.5-0.8, more preferably 0.6-0.8, for example 0.6015, 0.6025, 0.6128, 0.6172, 0.6381, 0.6423, 0.6451, 0.6521, 0.6563, 0.6579, 0.6593, 0.6599, 0.6686, 0.6738, 0.6824, 0.6867, 0.6882 or 0.7078.

[0101] In a fourth aspect, the present application provides a method for preparing the polyamide fiber as defined above, comprising the steps of drawing, washing, heat treating, oiling and winding the as-spun fiber as defined above.

[0102] In the present application, the drawing, washing, heat treating, oiling and winding are as defined above.

[0103] In a fifth aspect, the present application provides the use of the as-spun fiber or the polyamide fiber as defined above in textiles.

[0104] On the basis of common general knowledge in the art, the above-mentioned preferred conditions can be combined in any manner, thereby obtaining various preferred embodiments of the present application.

[0105] The reagents and raw materials used in the present application are commercially available.

[0106] The positive progress effects of the present application are as follows:

[0107] (1) The as-spun fiber of the present application has a smooth surface and a porous core-sheath structure in cross-section, has good strength and processability, and can be used for preparing polyamide fibers.

[0108] (2) The as-spun fiber of the present application is prepared by the wet spinning process, which avoids the problems of melt degradation, spinning flying, broken filaments and poor fiber mechanical properties caused by the high melting point of polyamide resin close to the thermal decomposition temperature, and can be suitable for high melting point polyamide resin, which is conducive to industrialized production.

[0109] (3) The polyamide fiber prepared from the as-spun fiber of the present application has high breaking strength, breaking elongation and initial modulus, and low boiling water shrinkage, dry heat shrinkage and broken filament frequency, and has excellent heat resistance, high strength and low shrinkage performance, which can be suitable for various application scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0110] Figure 1 SEM image of the as-spun fiber prepared in Example 1. DETAILED DESCRIPTION

[0111] The exemplary embodiments embodying the features and advantages of the present application will be described in detail hereinafter. It should be understood, however, that the application can be practiced in various ways and that the description and examples are not intended to limit the scope of the application, which is to be given the full scope of the appended claims. Methods for experiments not specifically described in the following examples were performed according to conventional methods and conditions, or as selected according to the manufacturer's instructions.

[0112] The raw materials used in the examples and comparative examples are as follows:

[0113] Raw material 1: Bio-based polyamide resin PA5XY, grade E-6290, relative viscosity after resin tackification 3.34, melting point 289°C.

[0114] Raw material 2: Bio-based polyamide resin PA5XY, grade E-6631, relative viscosity after resin tackification 5.0, melting point 267°C.

[0115] Raw material 3: Bio-based polyamide resin PA5XY, grade E-6632, relative viscosity after resin tackification 5.2, melting point 279°C.

[0116] Raw material 4: Bio-based polyamide resin PA5XY, grade E-6635, relative viscosity after resin tackification 3.2, melting point 298°C.

[0117] In the above raw materials 1-4, the specific method for resin tackification is to place the polyamide resin in a drying oven, dry for 100-180 h under vacuum and at 160-180°C, and the temperature and drying time are selected according to the target viscosity.

[0118] Raw material 5: Bio-based polyamide resin PA5XY, grade E-6290, relative viscosity 2.57, melting point 289°C.

[0119] Raw material 6: Bio-based polyamide resin PA5XY, grade E-6631, relative viscosity 3.27, melting point 267°C.

[0120] Raw material 7: Bio-based polyamide resin PA5XY, grade E-6632, relative viscosity 3.15, melting point 279°C.

[0121] Raw material 8: Bio-based polyamide resin PA5XY, grade E-6635, relative viscosity 2.73, melting point 298°C.

[0122] Raw material 9: bio-based polyamide resin PA5XY, prepared by the following method: 0.505 mol of 1,5-pentanediamine, 0.50 mol of 1,6-hexanediamine, 0.50 mol of 1,6-hexanedioic acid, 0.50 mol of terephthalic acid, 0.03 wt% of sodium hypophosphite, 0.3 wt% of antioxidant 1098, and water were uniformly mixed, heated to 80°C for 1.5 h, and then heated to 130°C to obtain a polyamide salt solution with a concentration of 65 wt%; the temperature was again increased to 250°C under a nitrogen atmosphere, and the pressure was maintained at 2.5 MPa for 1.5 h; the temperature was increased to 330°C while exhausting to normal pressure; and the pressure was reduced to -0.07 MPa and maintained for 40 min to obtain a polyamide melt, which was cooled and granulated to obtain a polyamide resin with a melting point of 275°C and a relative viscosity of 3.5 after tackifying the resin.

[0123] Raw material 10: bio-based polyamide resin PA5XY, prepared by the same method as raw material 9, except that the raw materials were 0.505 mol of 1,5-pentanediamine, 0.50 mol of 1,6-hexanediamine, 0.30 mol of 1,6-hexanedioic acid, 0.70 mol of terephthalic acid, 0.03 wt% of sodium hypophosphite, and 0.3 wt% of antioxidant 1098, to obtain a polyamide resin with a melting point of 300°C and a relative viscosity of 4.5 after tackifying the resin.

[0124] Raw material 11: bio-based polyamide resin PA5XY, prepared by the same method as raw material 9, except that the raw materials were 1.005 mol of 1,5-pentanediamine, 0.35 mol of 1,6-hexanedioic acid, 0.65 mol of terephthalic acid, 0.03 wt% of sodium hypophosphite, and 0.3 wt% of antioxidant 1098, to obtain a polyamide resin with a melting point of 287°C and a relative viscosity of 4.2 after tackifying the resin.

[0125] The melting points of the resins in the above raw materials were measured by differential scanning calorimetry (DSC).

[0126] Example 1

[0127] (1) Preparation of primary filaments: raw material 1 (trade name E-6290) was mixed with formic acid until the raw material 1 was completely dissolved to obtain a spinning solution, which was filtered, defoamed, and then extruded through the spinneret of a spinning plate into a coagulation bath to form primary filaments;

[0128] The relative viscosity of the raw material 1 was 3.34 Pa.s, the melting point was 289°C, the concentration of the spinning solution was 25 wt%, and the viscosity of the spinning solution was 24.2 Pa.s.

[0129] The temperature of the spinning solution was 40°C, the number of holes of the spinning plate was 80f, and the spinning rate was 1.65 m / min.

[0130] The coagulation bath is composed of a coagulant and water, the coagulant is formic acid, the temperature of the coagulation bath is 25℃, and the concentration of the solvent in the coagulation bath is 15wt%;

[0131] (2) Preparing the polyamide fiber: the as-spun yarn obtained in step (1) is drawn, washed, heat treated, oiled, and wound to obtain the polyamide fiber;

[0132] The drawing includes wet heat drawing and dry heat drawing, the temperature of the wet heat drawing is 80℃, the temperature of the dry heat drawing is 220℃, and the drawing multiple is 7.0 times; the washing agent used is water; the heat treatment includes drying and heat setting, and the specific steps of the heat treatment are as follows: drying at a temperature of 120℃, and then heat setting using a heat box at a temperature of 150℃; the oiling concentration is 1.80%; and the winding speed is 90 m / min.

[0133] Example 2-19

[0134] The raw materials and process parameters for preparing the as-spun yarn in Example 2-19 are shown in Table 1, and the process parameters for preparing the polyamide fiber are shown in Table 2, and the preparation steps of the as-spun yarn and the polyamide fiber are the same as those in Example 1.

[0135] Comparative Example 1

[0136] The resin raw material is the same as that in Example 1, and a melt spinning method is used, the polyamide raw material is put into a double-screw extruder, the screw temperature is set to be 295℃, 305℃, 310℃, and 320℃ in sequence, the spinning box temperature is 318℃, the spinning speed is 3000 m / min, the post-drawing multiple is 3.2 times, the drawing temperature is 100℃, and the heat setting temperature is 240℃.

[0137] Comparative Examples 2-4

[0138] The raw materials and spinning process parameters used in Comparative Examples 2-4 are shown in Table 1, and the others are the same as those in Comparative Example 1.

[0139] Comparative Example 5

[0140] The raw materials and process parameters for preparing the as-spun yarn in Comparative Example 5 are shown in Table 1, and the process parameters for preparing the polyamide fiber are shown in Table 2, and the preparation steps of the as-spun yarn and the polyamide fiber are the same as those in Example 1.

[0141] The as-spun yarn prepared in Comparative Example 5 has too low strength to perform the subsequent heat drawing and winding processes, and thus the polyamide fiber cannot be prepared.

[0142] Table 1 Raw materials and process parameters for preparing the as-spun yarn in Examples 1-19 and Comparative Examples 1-5

[0143]

[0144] Table 2 Process parameters for preparing polyamide fibers of Examples 1-19 and Comparative Examples 1-4

[0145]

[0146]

[0147] Effect Examples

[0148] The polyamide fibers prepared in Examples 1-19 and Comparative Examples 1-4 were tested as follows:

[0149] (1) Breaking strength, initial modulus, elongation at break: determined according to GB / T 14344-2008.

[0150] (2) Dry heat shrinkage: determined according to FZ / T 50004, with a heat treatment temperature of 180°C.

[0151] (3) Relative viscosity: determined by the Ubbelohde viscometer concentrated sulfuric acid method, with the following steps: accurately weigh 0.5±0.0002 g of the dried polyamide resin or fiber sample, add 50 mL of concentrated sulfuric acid (96%) to dissolve, measure and record the flow time t0 of the concentrated sulfuric acid and the flow time t of the polyamide 56 slice or short fiber sample solution in a 25°C constant temperature water bath. The relative viscosity calculation formula is: relative viscosity VN = t / t0; t - solution flow time; t0 - solvent flow time.

[0152] (6) Orientation degree: measured using a fiber acoustic velocity orientation instrument.

[0153] (7) Boiling water shrinkage: determined according to GB / 6505-2008 "Chemical fiber filament heat shrinkage test method", boiling water shrinkage = ((length before heat treatment - length after heat treatment) / length before heat treatment) * 100%.

[0154] (8) Single filament breaking times: manually counted.

[0155] Table 3 Mechanical property data of polyamide fibers prepared in Examples 1-19 and Comparative Examples 1-4

[0156]

[0157] Figure 1The SEM image of the as-spun fiber prepared in Example 1 shows that the surface of the as-spun fiber is smooth. As shown in Table 3, the polyamide fiber prepared in Examples 1-19 has a breaking strength of 3.42-5.26 cN / dtex, an elongation at break of 32.63%-43.50%, an initial modulus of 38.90-54.43 cN / dtex, a boiling water shrinkage of 5.04%-10.95%, a dry heat shrinkage at 177℃ for 2 min of 2.27%-7.30%, an orientation degree of 0.6015-0.7078, and a number of broken filaments of 0.2-1 times per 24 h, and has excellent mechanical properties.

[0158] As shown by the comparison between Example 1 and Comparative Example 5, when the viscosity of the spinning solution is less than 1 Pa.s, specifically 0.39 Pa.s in Comparative Example 5, the strength of the as-spun fiber prepared is too low to perform the subsequent heat-drawing and winding processes, and the as-spun fiber cannot be used to prepare the polyamide fiber.

[0159] Comparative Examples 1-4 are examples of preparing the polyamide fiber by the melt spinning method. In Comparative Example 1, the raw material used is the same as that in Example 1, but the breaking strength, elongation at break, and initial modulus of the polyamide fiber prepared in Comparative Example 1 are all lower than those in Example 1, and the boiling water shrinkage, dry heat shrinkage at 177℃ for 2 min, and number of broken filaments of the polyamide fiber prepared in Comparative Example 1 are all higher than those in Example 1, indicating that the polyamide fiber prepared in Comparative Example 1 is worse than that in Example 1 in all aspects.

[0160] In Comparative Example 2, the raw material used is the same as that in Example 2, but the breaking strength, elongation at break, initial modulus, and orientation degree of the polyamide fiber prepared in Comparative Example 2 are all lower than those in Example 2, and the boiling water shrinkage, dry heat shrinkage at 177℃ for 2 min, and number of broken filaments of the polyamide fiber prepared in Comparative Example 2 are all higher than those in Example 2, indicating that the polyamide fiber prepared in Comparative Example 2 is much worse than that in Example 2 in all aspects.

[0161] In Comparative Example 3, the raw material used is the same as that in Example 3, but the breaking strength, elongation at break, initial modulus, and orientation degree of the polyamide fiber prepared in Comparative Example 3 are all lower than those in Example 3, and the boiling water shrinkage, dry heat shrinkage at 177℃ for 2 min, and number of broken filaments of the polyamide fiber prepared in Comparative Example 3 are all higher than those in Example 3, indicating that the polyamide fiber prepared in Comparative Example 3 is worse than that in Example 3 in all aspects.

[0162] In Comparative Example 4, the raw material used is the same as that in Example 15, but the breaking strength, elongation at break, and initial modulus of the polyamide fiber prepared in Comparative Example 4 are all lower than those in Example 15, and the boiling water shrinkage, dry heat shrinkage at 177℃ for 2 min, and number of broken filaments of the polyamide fiber prepared in Comparative Example 4 are all higher than those in Example 15, indicating that the polyamide fiber prepared in Comparative Example 4 is worse than that in Example 15 in all aspects.

[0163] The above describes optional embodiments of the present application to teach those skilled in the art how to implement and reproduce the present application. Some conventional aspects have been simplified or omitted to teach the technical solutions of the present application. After reading the specification of the present application, those skilled in the art can easily conceive of variations or alternatives of the technical solutions of the present application that can achieve the purposes of the present application according to the common knowledge in the chemical field, and those skilled in the art should understand that the variations or alternatives derived from these embodiments will fall within the scope of the present application.

Claims

1. A primary filament, characterized in that, The wet spinning solution is used to form the primary filament by wet spinning; The viscosity of the wet spinning solution is not less than 1 Pa·s; The wet spinning solution comprises a polyamide and a solvent; the polyamide comprises at least one diamine unit and at least one diacid unit, the diacid unit comprises at least one aliphatic diacid unit and at least one aromatic diacid unit, and the diamine unit comprises at least one pentanediamine unit.

2. The primary filament of claim 1, wherein The molar ratio of the diamine unit to the diacid unit is (0.9-1.2):1; The molar ratio of the aliphatic diacid unit to the aromatic diacid unit is (10-50):(50-90); The molar percentage of the pentanediamine unit in the diamine unit is 20-100%.

3. The primary filament of claim 1 wherein, The molar ratio of the diamine unit to the diacid unit is (0.95-1.1):1; The molar ratio of the aliphatic diacid unit to the aromatic diacid unit is (20-50):(50-75); The molar percentage of the pentanediamine unit in the diamine unit is 20-70%.

4. The primary filament of claim 1, wherein The diamine unit is derived from an aliphatic diamine; The aliphatic diacid unit is derived from an aliphatic short-chain diacid and / or an aliphatic long-chain diacid; The aromatic diacid unit is derived from an aromatic diacid and / or an aromatic diacid derivative.

5. The primary filament of claim 4, wherein The aliphatic diamine is butanediamine, hexanediamine, heptanediamine, octanediamine, nonanediamine, decanediamine, undecanediamine, dodecanediamine, tridecanediamine, tetradecanediamine, pentadecanediamine, hexadecanediamine, or a combination thereof; The aliphatic short-chain diacid comprises oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, or a combination thereof; The aliphatic long-chain diacid comprises azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, or a combination thereof; The aromatic diacid unit is derived from phthalic acid and / or phthalate.

6. The primary silk of claim 5, wherein, The pentanediamine is a bio-based pentanediamine; The aliphatic short-chain diacid comprises adipic acid; The phthalic acid is one or more of terephthalic acid, isophthalic acid, and phthalic acid; The aliphatic long-chain diacid comprises sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, or a combination thereof; The phthalate is a terephthalate. The terephthalate is dimethyl terephthalate and / or diethyl terephthalate.

7. The primary filament of claim 6, wherein The viscosity of the wet spinning solution is 1-100 Pa·s; 8. The primary silk of claim 1, wherein The concentration of the wet spinning solution is 3-70%, the percentage being the mass percentage of the polyamide in the wet spinning solution; The relative viscosity of the polyamide is 1.2-6.0; The melting point of the polyamide is 250-320℃; ​ And / or, the polyamide further comprises an additive; Wherein, the additive comprises a heat stabilizer, an antioxidant, a fluorescent whitening agent, a pigment, a dye, an anti-UV agent, a flame retardant, a flow modifier, an organic filler, an inorganic filler, a powder binder, or a combination thereof. Wherein, the heat stabilizer is phosphoric acid, phosphorous acid, trimethyl phosphite, triphenyl phosphite, trimethyl phosphate, triphenyl phosphate, sodium hypophosphite, zinc hypophosphite, calcium hypophosphite, potassium hypophosphite, or a combination thereof. Wherein, the antioxidant is selected from one or more of a hindered phenol antioxidant, a hindered amine antioxidant, and a phosphite antioxidant. and / or the solvent is dimethylformamide, dimethylacetamide, dimethylsulfoxide, N one or more of methylpyrrolidone, aqueous sodium thiocyanate, aqueous zinc chloride, nitric acid, sulfuric acid, formic acid, acetic acid, dichloromethane, benzene, toluene, xylene, methanol, ethanol, phenol, and chloroform.

9. The primary silk of claim 8, wherein, The viscosity of the spinning solution is 15-50 Pa·s. And / or, the concentration of the spinning solution is 5-55%. And / or, the relative viscosity of the polyamide is 2.0-5.

2. And / or, the melting point of the polyamide is 260-310℃. And / or, the antioxidant is one or more of antioxidant 168, antioxidant 1098, antioxidant 1010, and antioxidant S9228.

10. The primary silk of claim 8, wherein The concentration of the spinning solution is 10-50%. And / or, the additive comprises a heat stabilizer, an antioxidant, a fluorescent whitening agent, a pigment, a dye, an anti-UV agent, a flame retardant, a flow modifier, an organic filler, a silica powder, a carbon nanotube, a powder binder, or a combination thereof.

11. The primary silk of claim 1, wherein The wet spinning comprises the following steps: spinning and coagulating the spinning solution.

12. The primary silk of claim 11, wherein, The wet spinning comprises the following steps: the spinning solution enters the coagulation bath through the spinneret. And / or, the spinning device comprises a spinneret or a spinneret and a spinneret plate.

13. The primary silk of claim 12, wherein Wherein, The coagulation bath comprises water and / or a coagulant; And / or, the temperature of the coagulation bath is 3-80℃. And / or, the number of holes of the spinneret plate is 5-100000 f; And / or, the temperature of the spinning solution is 5-100℃.

14. The primary silk of claim 13, wherein Wherein, The concentration of the coagulant is 0.1-55%, the percentage being the percentage of the coagulant in the total volume of the coagulation bath; and / or the coagulant is dimethylformamide, dimethylacetamide, dimethyl sulfoxide, N one or more of methylpyrrolidone, aqueous sodium thiocyanate, aqueous zinc chloride, nitric acid, sulfuric acid, formic acid, acetic acid, dichloromethane, benzene, toluene, xylene, methanol, ethanol, phenol, and chloroform; And / or, the temperature of the coagulation bath is 10-60℃. And / or, the number of holes of the spinneret plate is 10-50000 f; Wherein, the spinning rate of the spinning is 0.1-6 m / min; And / or, the spinning further comprises the steps of defoaming and filtering the spinning solution before spinning; And / or, the temperature of the spinning solution is 10-80℃.

15. The primary silk of claim 14, wherein, The concentration of the coagulant is 0.1-45%; And / or, the temperature of the coagulation bath is 15-45℃. And / or, the spinning rate of the spinning is 1-3 m / min; And / or, the defoaming uses vibration defoaming or adding a defoaming agent to defoam; And / or, the temperature of the spinning solution is 15-45℃.

16. A process for the production of a primary filament as claimed in any one of claims 1 to 15, characterised in that, It comprises the following steps: The wet spinning solution forms a nascent filament; wherein, the viscosity of the spinning solution is not less than 1 Pa·s; the spinning solution comprises a polyamide and a solvent; the polyamide contains at least one diamine unit and at least one diacid unit, the diacid unit contains at least one aliphatic diacid unit and at least one aromatic diacid unit, and the diamine unit contains at least one pentanediamine unit.

17. A polyamide fiber characterized in that, It is manufactured by drawing, washing, heat treating, oiling and winding the as-spun yarn as claimed in any one of claims 1 to 15.

18. The polyamide fiber of claim 17, wherein, The drawing mode of the drawing is wet heat drawing and / or dry heat drawing; The temperature of the wet heat drawing is 20 to 95°C; The temperature of the dry heat drawing is 96 to 260°C; The multiple of the drawing is 1 to 20 times; The washing agent of the washing is water or / and ethanol; The heat treatment includes drying and heat setting; The temperature of the drying is 25 to 250°C; The temperature of the heat setting is 100 to 280°C; The heat setting is performed by high temperature and high pressure steam or a heat box; The oil concentration of the oiling is 1 to 5%; The winding speed is 10 to 1000 m / min.

19. The polyamide fiber of claim 18, wherein, The temperature of the wet heat drawing is 25 to 85°C; The temperature of the dry heat drawing is 100 to 250°C; The temperature of the drying is 50 to 220°C; The temperature of the heat setting is 130 to 260°C; The oil concentration of the oiling is 1.5 to 3%; The winding speed is 20 to 700 m / min.

20. The polyamide fiber of claim 18, wherein The winding speed is 30 to 500 m / min.

21. A process for the production of the polyamide fibre as claimed in any one of claims 17 to 20, characterised in that, It comprises the steps of drawing, washing, heat treating, oiling and winding the as-spun yarn.

22. Use of the as-spun yarn as claimed in any one of claims 1 to 15 or the polyamide fiber as claimed in any one of claims 17 to 20 in a textile.

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