Superfine nylon fiber and textile thereof

Abstract

The invention discloses a superfine nylon fiber and a textile thereof, the diameter of the cross section of a single fiber of the superfine nylon fiber is 3.0-15.0 microns, the superfine nylon fiber contains nitrogen-series flame-retardant particles, and the ratio of the average particle size of the nitrogen-series flame-retardant particles to the diameter of the cross section of the single fiber is 0.02-0.33. The superfine nylon fiber disclosed by the invention not only has good spinning performance and mechanical property, but also has good flame retardant property, and the wearing comfort and safety of clothes are improved.

Description

Technical Field

[0001] The present invention relates to an ultrafine nylon fiber and a textile thereof, and more particularly to an ultrafine nylon fiber with excellent flame retardant properties. Background Art

[0002] Clothing made from nylon fibers is comfortable and popular with consumers. However, nylon fibers are flammable and burn quickly, melting rapidly during combustion and clinging to skin. Textiles made from ultrafine nylon fibers are particularly lightweight and thin. Compared to textiles made from standard-denier nylon fibers, they require less heat to burn and are therefore more likely to continue burning. If a fire occurs while the garment is being worn, it can cause significant harm.

[0003] In the existing technology, nylon fibers and textiles can be flame-retarded by flame-retardant coating processes and direct addition of flame retardants. However, the nylon fibers or textiles obtained by the flame-retardant coating process have poor flame retardant durability after multiple washings. Therefore, the method of directly adding flame retardants is more commonly used.

[0004] A Chinese patent (CN110923848A) discloses a flame-retardant polyamide fiber. The fibers are obtained by melt-spinning polyamide chips made by melt-blending polyamide with melamine cyanurate, graphite-like carbon nitride, a zinc compound, and a DOPO derivative. However, the resulting fibers are relatively coarse and can only be used in industrial applications. Summary of the Invention

[0005] The object of the present invention is to provide an ultrafine nylon fiber and textiles thereof having both spinnability, mechanical properties and flame retardancy.

[0006] The technical solution of the present invention is:

[0007] Ultrafine nylon fiber, the single fiber cross-sectional diameter of which is 3.0 to 15.0 microns; the ultrafine nylon fiber contains nitrogen-based flame-retardant particles, and the ratio of the average particle size of the nitrogen-based flame-retardant particles to the single fiber cross-sectional diameter is 0.02 to 0.33.

[0008] The average particle size of the nitrogen-based flame retardant particles is preferably 0.30 to 1.00 microns.

[0009] The nitrogen-based flame retardant particles are preferably one or more of melamine cyanurate, melamine phosphate, and guanidine phosphate.

[0010] The nitrogen-based flame-retardant particles preferably account for 3.0 to 15.0 wt % of the ultrafine nylon fiber.

[0011] The fiber-forming polymer of the ultrafine nylon fiber is preferably one or more of polyamide 6, polyamide 66, polyamide 56, and polyamide 610.

[0012] The present invention utilizes melt spinning technology to uniformly disperse nitrogen-based flame-retardant particles in nylon ultrafine fibers, and by effectively controlling the relationship between the single fiber diameter and the particle size of the nitrogen-based flame-retardant particles, the ultrafine nylon fibers have good spinning and mechanical properties as well as excellent flame-retardant properties, and can be used to prepare clothing or decorative textiles. DETAILED DESCRIPTION

[0013] The single fiber diameter of ultrafine fibers is small, and instability is likely to occur when they are spun alone. When flame retardant particles are added to the blended fibers for spinning, the spinning performance and mechanical properties of the fibers are more likely to be affected.

[0014] The present invention provides an ultrafine nylon fiber with excellent flame retardancy and mechanical properties, while maintaining spinnability. The fiber has a single fiber cross-sectional diameter of 3.0 to 15.0 microns. When the single fiber cross-sectional diameter is greater than 15.0 microns, the fiber has high bending rigidity, resulting in a stiff feel to the resulting textile. When the single fiber cross-sectional diameter is less than 3.0 microns, spinning becomes difficult, making mass production difficult, and the resulting textile exhibits poor stiffness. Considering the fiber's spinnability, the feel, and stiffness of the resulting textile, the ultrafine nylon fiber preferably has a single fiber cross-sectional diameter of 6.0 to 10.0 microns.

[0015] Because ultrafine fibers have a larger specific surface area, their contact area with combustible gases (such as oxygen, hydrogen, etc.) is larger, and the energy required to cause combustion is also less. Therefore, textiles made of ultrafine fibers are easier to burn than nylon of ordinary diameter.

[0016] The present invention incorporates flame-retardant particles into ultrafine nylon fibers by blending nylon chips and flame-retardant particles and then spinning them. Flame retardants primarily impart flame retardancy to ultrafine nylon fibers through mechanisms such as heat absorption, coating, chain reaction inhibition, and the generation of non-combustible gases. The flame retardant mechanisms vary depending on the flame retardant. Commonly used flame retardants include halogen-based, metal oxide-based, phosphorus-based, and nitrogen-based flame retardants. Nitrogen-based flame retardants are preferred due to their long ignition time, high heat release rate, low toxicity, fiber-resistance, and minimal impact on the fiber's physical and chemical properties.

[0017] There are no specific restrictions on the type of nitrogen-based flame-retardant particles. However, for use in textiles, nitrogen-based flame-retardant particles preferably exhibit good thermal stability, are non-reactive with organic polymers, are non-toxic, and do not produce harmful substances upon combustion. The nitrogen-based flame-retardant particles of the present invention are preferably one or more of melamine cyanurate, melamine phosphate, and guanidine phosphate.

[0018] The ratio of the average particle size of the nitrogen-based flame-retardant particles to the cross-sectional diameter of the single fiber has a great relationship with the mechanical properties and flame retardant properties of the ultrafine fibers. When the content of the nitrogen-based flame-retardant particles in the ultrafine nylon fiber is consistent, the smaller the ratio of the average particle size of the nitrogen-based flame-retardant particles to the cross-sectional diameter of the single fiber, the greater the number of nitrogen-based flame-retardant particles, the larger the total contact area between the nitrogen-based flame-retardant particles and the fiber, the more heat can be taken away during combustion, and a carbonized layer can be formed on the fiber surface, and the better the flame retardant effect of the ultrafine nylon fiber. However, an increase in the number of nitrogen-based flame-retardant particles will reduce the mechanical properties and spinnability of the ultrafine nylon fiber. The present invention limits the ratio of the average particle size of the nitrogen-based flame-retardant particles to the cross-sectional diameter of the single fiber to 0.02 to 0.33. When the ratio of the average particle size of the nitrogen-based flame-retardant particles to the cross-sectional diameter of the single fiber is less than 0.02, while a good flame retardant effect is achieved, the spinning process results in poor filtration performance and poor mechanical properties of the resulting fiber. When the ratio of the average particle size of the nitrogen-based flame-retardant particles to the cross-sectional diameter of the single fiber is greater than 0.33, the flame retardant effect of the fiber does not meet the requirements. In addition, uneven dispersion of the particles in the fiber also results in poor filtration performance and reduced mechanical properties of the fiber. To achieve better flame retardant effect and mechanical properties for ultrafine nylon fibers, the ratio of the average particle size of the nitrogen-based flame-retardant particles to the cross-sectional diameter of the single fiber is more preferably 0.03 to 0.17.

[0019] In order to further maintain a balance between the flame retardant effect and the mechanical properties of the ultrafine nylon fiber, the present invention preferably has an average particle size of the nitrogen-based flame retardant particles of 0.30 to 1.00 μm.

[0020] Without affecting the flame retardancy, spinnability, and mechanical properties of the ultrafine nylon fiber, the content of nitrogen-based flame-retardant particles in the ultrafine nylon fiber can be arbitrarily varied within the range of conventional flame retardant contents in the prior art. As the content of nitrogen-based flame-retardant particles decreases, the spinnability and mechanical properties of the ultrafine nylon fiber increase, while the flame retardancy decreases; as the content of nitrogen-based flame-retardant particles increases, the spinnability and mechanical properties of the ultrafine nylon fiber decrease, while the flame retardancy increases. The present invention preferably contains 3.0 to 15.0 wt%, and more preferably 5.0 to 10.0 wt%, to obtain an ultrafine nylon fiber with excellent flame retardancy, spinnability, and mechanical properties.

[0021] The present invention does not particularly limit the fiber-forming polymer of the ultrafine nylon fiber. Any polyamide polymer suitable for clothing fabrics can be used. Particularly preferred are polyamide 6, polyamide 66, polyamide 56, polyamide 610, polyamide 510, polyamide 1010, polyamide 612, polyamide 11, polyamide 12, and polyamide 46, and one or more of the better polyamide 6, polyamide 66, polyamide 56, and polyamide 610.

[0022] The present invention does not particularly limit the preparation method of the ultrafine nylon fiber, and conventional methods in the prior art can be used. Specifically, for example, polyamide chips and nitrogen-based flame-retardant particles are first blended, and then the blend is added to a screw extruder for melt extrusion, and then the melt is pressed into a spinning assembly and spitted out from a spinneret. Afterwards, depending on the type of target fiber (POY, FDY, DTY), multiple steps can be selected from cooling, oiling, entanglement, drawing, false twisting, winding, etc. to obtain ultrafine nylon extended yarn, ultrafine nylon fully drawn yarn or ultrafine nylon false twisted yarn. The average particle size of the nitrogen-based flame-retardant particles added during the blending can satisfy the ratio of the average particle size of the nitrogen-based flame-retardant particles in the ultrafine nylon fiber to the cross-sectional diameter of the single fiber to be 0.02 to 0.33. However, in order to improve the spinnability during the preparation process, the average particle size of the nitrogen-based flame-retardant particles cannot be too small, otherwise the particles are prone to agglomeration and difficult to disperse, resulting in problems such as difficulty in filtration during spinning and poor spinnability; the average particle size of the nitrogen-based flame-retardant particles cannot be too large, otherwise it is difficult to disperse during spinning, resulting in poor spinnability and a decrease in the mechanical properties of the resulting fiber.

[0023] The ultrafine nylon fibers of the present invention not only have a soft hand feel but also exhibit excellent flame retardancy and can be spun into textiles such as woven and knitted fabrics. In a preferred embodiment, the resulting textile exhibits a limiting oxygen index (LOI) of 26% or greater as measured by ISO 4589-2-2017 and a flame retardancy of three or more as measured by JIS L 1901:1999 D (flame contact test).

[0024] The present invention relates to a parameter testing method as follows:

[0025] (1) Particle size

[0026] The particles in the ultrafine nylon fiber were observed using a transmission electron scanning microscope (TEM), and the diameters of individual particles in different directions were measured using the relevant ruler tool in the microscope. The average value obtained by measuring 10 times was used to express the particle size of the spherical particles as follows:

[0027]

[0028] D: particle size of spherical particles; A i : the i-th test diameter of a single particle; i: the number of measurements.

[0029] (2) Single fiber cross-sectional diameter

[0030] The cross section of the ultrafine nylon fiber was observed by electron scanning microscopy (SEM), and the diameter in the cross section direction was measured using the relevant ruler tool in the microscope. The average value of 10 fibers was used to express the fiber diameter:

[0031]

[0032] d: single fiber diameter; a i : the test diameter of the i-th fiber; i: the number of measurements.

[0033] (3) Nitrogen flame retardant particles account for the content of ultrafine nylon fibers

[0034] Take ultrafine nylon fiber weighing Wa and place it in a beaker. Then add a certain amount of nylon solvent (hexafluoroisopropanol or dimethylaminoformamide) to the beaker. After the fiber is completely dissolved, disperse the residual powder in water and centrifuge it. Dry the residual powder at 60°C and weigh the weight of the dried powder as Wx.

[0035] Repeat the above operation 10 times and obtain the average value.

[0036]

[0037] Wa i : Weight of ultra-fine nylon fiber; Wx i : The residual weight of the ultrafine nylon fiber after dissolution, i: the number of measurements.

[0038] (4) Flame retardant properties of textiles

[0039] The ultra-fine nylon fiber is woven into a gram weight of 100g / m 2 The textiles were then tested for their limiting oxygen index (LOI) according to ISO 4589-2-2017, and their flame exposure times according to JIS L 1901:1999D (flame exposure test).

[0040] When the LOI value of textiles made of ultrafine nylon fibers reaches 26% or more and the number of flame contacts reaches 3 or more, it is judged as excellent; when the LOI value of textiles made of ultrafine nylon fibers reaches 26% or more, or the number of flame contacts reaches 3 or more, it is judged as good; when the LOI value of textiles made of ultrafine nylon fibers is less than 26% and the number of flame contacts is less than 3, it is judged as poor.

[0041] (5) Tensile strength and Young's modulus of fibers

[0042] The Young's modulus and tensile strength of ultrafine nylon fibers were measured according to ASTM C1557-20. The greater the Young's modulus, the greater the rigidity of the fiber.

[0043] (6) Spinnability

[0044] The spinnability is determined by the filtration pressure of the polymer and the occurrence of broken or drifting fibers during spinning.

[0045] Filtration pressure: The flow rate of the nylon molten composition per unit area of ​​the filter is 3.0 g per minute. The filtration pressure for 12 hours is less than 2 MPa, which is judged as ○. The filtration pressure is 2-5 MPa, which is judged as Δ. The filtration pressure is greater than 5 MPa, which is judged as ×.

[0046] Fiber breakage: If the number of fiber breakages within 12 hours during spinning is less than 2, it is judged as ○; if the number of fiber breakages is 2 to 5, it is judged as Δ; if the number of fiber breakages is more than 5, it is judged as ×.

[0047] Floating yarn: If the number of floating yarns within 12 hours during spinning is less than 2 times, it is judged as ○; if the number of floating yarns is 2 to 5 times, it is judged as Δ; if the number of floating yarns is more than 5 times, it is judged as ×.

[0048] When the filtration pressure, broken yarns, and floating yarns are all judged as ○, the spinnability is judged as ○; when the three are all judged as ×, the spinnability is judged as ×; all other cases are judged as Δ.

[0049] The present invention is further described in detail below by way of examples.

[0050] Example 1

[0051] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.10. The resulting single fiber had a cross-sectional diameter of 10.0 μm, melamine cyanurate particles accounted for 5.0% by weight of the fiber, a Young's modulus of 2.3 GPa, and a tensile strength of 5.8 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 26% and a flame contact time of 3. Specific physical properties are shown in Table 1.

[0052] Example 2

[0053] Polyamide 66 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.10. The resulting single fiber had a cross-sectional diameter of 10.0 μm, melamine cyanurate particles accounted for 5.0% by weight of the fiber, a Young's modulus of 3.1 GPa, and a tensile strength of 5.5 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 27% and a flame contact time of 3. Specific physical properties are shown in Table 1.

[0054] Example 3

[0055] Polyamide 56 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.1. The resulting single fiber had a cross-sectional diameter of 10.0 μm, melamine cyanurate particles accounted for 5.0% by weight of the fiber, a Young's modulus of 2.9 GPa, and a tensile strength of 4.9 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 27% and a flame contact number of 4. Specific physical properties are shown in Table 1.

[0056] Example 4

[0057] Polyamide 610 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.1. The resulting single fiber had a cross-sectional diameter of 10.0 μm, melamine cyanurate particles accounted for 5.0% by weight of the fiber, a Young's modulus of 2.9 GPa, and a tensile strength of 4.3 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 28% and a flame contact time of 4. Specific physical properties are shown in Table 1.

[0058] Example 5

[0059] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of average particle size to single fiber cross-sectional diameter of 0.33. The resulting single fiber had a cross-sectional diameter of 3.0 μm, 9.0 wt% of melamine cyanurate particles, a Young's modulus of 1.3 GPa, and a tensile strength of 4.8 cN / dtex. The textile fabric made from these ultrafine nylon fibers exhibited a LOI of 26% and a flame contact rate of 3. Specific physical properties are shown in Table 1.

[0060] Example 6

[0061] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of average particle size to single fiber cross-sectional diameter of 0.17. The resulting single fiber had a cross-sectional diameter of 6.0 μm, 9.0 wt% of melamine cyanurate particles, a Young's modulus of 1.9 GPa, and a tensile strength of 5.2 cN / dtex. The textile fabric made from these ultrafine nylon fibers exhibited a LOI of 26% and a flame contact rate of 3. Specific physical properties are shown in Table 1.

[0062] Example 7

[0063] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.10. The resulting single fiber had a cross-sectional diameter of 10.0 μm, 9.0 wt% of the melamine cyanurate particles, a Young's modulus of 2.5 GPa, and a tensile strength of 5.2 cN / dtex. The textile made from these ultrafine nylon fibers exhibited a LOI of 27% and a flame contact rate of 4. Specific physical properties are shown in Table 1.

[0064] Example 8

[0065] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of average particle size to single fiber cross-sectional diameter of 0.07. The resulting single fiber cross-sectional diameter was 15.0 μm. The melamine cyanurate particles accounted for 9.0% by weight of the fibers. The fiber had a Young's modulus of 3.1 GPa and a tensile strength of 5.3 cN / dtex. The textile fabric composed of these ultrafine nylon fibers exhibited a LOI of 27% and a flame contact number of 4. Specific physical properties are shown in Table 1.

[0066] Comparative Example 1

[0067] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.05. The resulting single fiber had a cross-sectional diameter of 20.0 μm, 9.0 wt% of the melamine cyanurate particles, a Young's modulus of 3.9 GPa, and a tensile strength of 5.3 cN / dtex. The textile made from these ultrafine nylon fibers exhibited a LOI of 27% and a flame contact rate of 4. Specific physical properties are shown in Table 1.

[0068] Since the fiber diameter is too large, the Young's modulus of the fiber is too large, that is, the bending rigidity of the fiber is large, and the textiles made from the fiber have a hard feel.

[0069] Comparative Example 2

[0070] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of average particle size to single fiber cross-sectional diameter of 0.40. The resulting single fiber had a cross-sectional diameter of 2.5 μm, 9.0 wt% of melamine cyanurate particles, a Young's modulus of 1.0 GPa, and a tensile strength of 4.5 cN / dtex. The textile fabric made from these ultrafine nylon fibers had a LOI of 25% and a flame contact time of 2. Specific physical properties are shown in Table 1.

[0071] Because the fiber diameter is too small and the ratio of the average particle size of the flame retardant particles to the fiber cross-sectional diameter is too large, spinning is difficult, quantitative production is difficult to achieve, and the fiber strength is low.

[0072] Example 9

[0073] Polyamide 66 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.06. The resulting single fiber had a cross-sectional diameter of 8.0 μm, melamine cyanurate particles accounted for 5.0% by weight of the fiber, a Young's modulus of 3.1 GPa, and a tensile strength of 5.3 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 27% and a flame contact time of 3. Specific physical properties are shown in Table 1.

[0074] Example 10

[0075] Polyamide 66 and melamine cyanophosphate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.06. The resulting single fiber had a cross-sectional diameter of 8.0 μm, melamine cyanophosphate particles accounted for 5.0% by weight of the fiber, a Young's modulus of 3.1 GPa, and a tensile strength of 5.4 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 28% and a flame contact time of 3. Specific physical properties are shown in Table 1.

[0076] Example 11

[0077] Polyamide 66 and guanidine phosphate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.06. The resulting single fiber had a cross-sectional diameter of 8.0 μm, guanidine phosphate particles accounted for 5.0% by weight of the fiber, a Young's modulus of 3.2 GPa, and a tensile strength of 5.2 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 26% and a flame contact time of 4. Specific physical properties are shown in Table 1.

[0078] Comparative Example 3

[0079] Polyamide 66 and antimony trioxide were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.06. The resulting single fiber had a cross-sectional diameter of 8.0 μm, antimony trioxide particles accounted for 5.0% by weight of the fiber, a Young's modulus of 3.2 GPa, and a tensile strength of 5.5 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 23% and a flame contact time of 2. Specific physical properties are shown in Table 1.

[0080] Since antimony trioxide flame retardant particles are used, their flame retardant properties are poorer than those of ammonia flame retardant particles.

[0081] Comparative Example 4

[0082] Polyamide 66 and ammonium polyphosphate were blended and spun to produce ultrafine nylon fibers with a ratio of average particle size to single fiber cross-sectional diameter of 0.06. The resulting single fiber had a cross-sectional diameter of 8.0 μm, 5.0% by weight of ammonium polyphosphate particles, a Young's modulus of 3.1 GPa, and a tensile strength of 5.1 cN / dtex. The textile fabric made from these ultrafine nylon fibers exhibited a LOI of 22% and a flame contact count of 2. Specific physical properties are shown in Table 1.

[0083] Since ammonium polyphosphate flame retardant particles are used, its flame retardant performance is poorer than that of ammonia flame retardant particles.

[0084] Example 12

[0085] Polyamide 56 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.10. The resulting single fiber had a cross-sectional diameter of 3.0 μm, 8.0 wt% of the melamine cyanurate particles, a Young's modulus of 2.5 GPa, and a tensile strength of 4.2 cN / dtex. The textile made from these ultrafine nylon fibers exhibited a LOI of 29% and a flame contact rate of 4. Specific physical properties are shown in Table 2.

[0086] Example 13

[0087] Polyamide 56 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of average particle size to single fiber cross-sectional diameter of 0.20. The resulting single fiber had a cross-sectional diameter of 3.0 μm, 8.0 wt% of melamine cyanurate particles, a Young's modulus of 2.5 GPa, and a tensile strength of 4.5 cN / dtex. The textile fabric made from these ultrafine nylon fibers exhibited a LOI of 28% and a flame contact rate of 3. Specific physical properties are shown in Table 2.

[0088] Example 14

[0089] Polyamide 56 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of average particle size to single fiber cross-sectional diameter of 0.33. The resulting single fiber had a cross-sectional diameter of 3.0 μm, 8.0 wt% of the melamine cyanurate particles, a Young's modulus of 2.3 GPa, and a tensile strength of 4.0 cN / dtex. The textile fabric made from these ultrafine nylon fibers exhibited a LOI of 27% and a flame contact rate of 3. Specific physical properties are shown in Table 2.

[0090] Example 15

[0091] Polyamide 56 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.02. The resulting single fiber had a cross-sectional diameter of 3.0 μm, 8.0% by weight of the melamine cyanurate particles, a Young's modulus of 2.4 GPa, and a tensile strength of 4.0 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 30% and a flame contact number of 4. Specific physical properties are shown in Table 2.

[0092] Comparative Example 5

[0093] Polyamide 56 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of average particle size to single fiber cross-sectional diameter of 0.40. The resulting single fiber had a cross-sectional diameter of 3.0 μm, 8.0 wt% of melamine cyanurate particles, a Young's modulus of 2.3 GPa, and a tensile strength of 3.7 cN / dtex. The textile fabric composed of these ultrafine nylon fibers exhibited a LOI of 25% and a flame contact time of 2. Specific physical properties are shown in Table 2.

[0094] Because the ratio of the average particle size of the nitrogen-based flame-retardant particles to the cross-sectional diameter of the single fiber is too large, the number of nitrogen-based flame-retardant particles is smaller than in Examples 12 to 15, and the heat absorbed during combustion is relatively small, resulting in poor flame retardancy of the fiber. Furthermore, the large particle size results in poor mechanical properties of the fiber.

[0095] Example 16

[0096] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.10. The resulting single fiber had a cross-sectional diameter of 10.0 μm, melamine cyanurate particles accounted for 3.0 wt% of the fiber, a Young's modulus of 2.5 GPa, and a tensile strength of 6.1 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 26% and a flame contact time of 3. Specific physical properties are shown in Table 2.

[0097] Example 17

[0098] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.10. The resulting single fiber had a cross-sectional diameter of 10.0 μm, melamine cyanurate particles accounted for 6.0% by weight of the fiber, a Young's modulus of 2.3 GPa, and a tensile strength of 5.7 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 27% and a flame contact time of 4. Specific physical properties are shown in Table 2.

[0099] Example 18

[0100] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.10. The resulting single fiber had a cross-sectional diameter of 10.0 μm, melamine cyanurate particles accounted for 10.0% by weight of the fiber, a Young's modulus of 2.3 GPa, and a tensile strength of 5.1 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 28% and a flame contact time of 4. Specific physical properties are shown in Table 2.

[0101] Example 19

[0102] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.10. The resulting single fiber had a cross-sectional diameter of 10.0 μm, melamine cyanurate particles accounted for 15.0% by weight of the fiber, a Young's modulus of 2.2 GPa, and a tensile strength of 4.5 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 29% and a flame contact time of 5. Specific physical properties are shown in Table 2.

[0103] Example 20

[0104] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.10. The resulting single fiber had a cross-sectional diameter of 10.0 μm, melamine cyanurate particles accounted for 1.0 wt% of the fiber, a Young's modulus of 2.3 GPa, and a tensile strength of 6.4 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 24% and a flame contact time of 2. Specific physical properties are shown in Table 2.

[0105] Example 21

[0106] Polyamide 6 and melamine cyanurate were blended and spun to produce ultrafine nylon fibers with a ratio of the average particle size of the fibers to the cross-sectional diameter of the single fiber of 0.10. The resulting single fiber had a cross-sectional diameter of 10.0 μm, melamine cyanurate particles accounted for 20.0% by weight of the fiber, a Young's modulus of 2.1 GPa, and a tensile strength of 3.9 cN / dtex. The textile made from these ultrafine nylon fibers had a LOI of 32% and a flame contact time of 5. Specific physical properties are shown in Table 2.

[0107]

[0108]

Claims

1. Ultrafine nylon fiber, characterized by: The single fiber cross-sectional diameter of the ultrafine nylon fiber is 3.0 to 15.0 microns; the ultrafine nylon fiber contains nitrogen-based flame-retardant particles, and the ratio of the average particle size of the nitrogen-based flame-retardant particles to the single fiber cross-sectional diameter is 0.02 to 0.

33.

2. The ultrafine nylon fiber according to claim 1, characterized in that: The average particle size of the nitrogen-based flame retardant particles is 0.30 to 1.00 microns.

3. The ultrafine nylon fiber according to claim 1 or 2, characterized in that: The nitrogen-based flame retardant particles are one or more of melamine cyanurate, melamine phosphate, and guanidine phosphate.

4. The ultrafine nylon fiber according to claim 1 or 2, characterized in that: The nitrogen-based flame-retardant particles account for 3.0 to 15.0 wt % of the ultrafine nylon fiber.

5. The ultrafine nylon fiber according to claim 1 or 2, characterized in that: The fiber-forming polymer of the ultrafine nylon fiber is one or more of polyamide 6, polyamide 66, polyamide 56, and polyamide 610.

6. Textiles mainly made from the ultrafine nylon fibers according to claim 1.

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