阅读说明：本技术 一种氨纶纤维截面形状可控的方法 (Method for controlling cross-sectional shape of spandex fiber ) 是由 吴志豪 杨晓印 孔懿阳 毛植森 陈斌 项超力 于 2020-11-23 设计创作，主要内容包括：本发明公开了一种氨纶纤维截面形状可控的方法,该方法通过如下步骤实现：控制粘度为2000～5000poise的聚氨酯脲纺丝溶液A的温度为50～80℃,控制粘度为1000～6000poise的碱溶性树脂纺丝溶液B的温度为60～120℃；将喷丝板上分布1个或1个以上的喷丝孔,所述的喷丝孔包括具有同心结构的内芯、外层结构通道,形成复合结构喷丝孔的喷丝板；将纺丝溶液A、纺丝溶液B通过喷丝板,纺丝溶液A从喷丝孔的内芯喷出,所述纺丝溶液B从喷丝孔的外层喷出,在甬道烘干中去除溶液中的可挥发性溶剂得到纤维预成品；将纤维预成品经碱溶液浸泡、烘干、冷却定型后,得到氨纶纤维。该纤维截面形状可控的氨纶,纤维在甬道去除溶剂过程中不会出现纤维截面形状变化的现象,且产品S力学性能优异。(The invention discloses a method for controlling the cross section shape of spandex fiber, which is realized by the following steps: controlling the temperature of a polyurethane urea spinning solution A with the viscosity of 2000-5000 poise to be 50-80 ℃, and controlling the temperature of an alkali-soluble resin spinning solution B with the viscosity of 1000-6000 poise to be 60-120 ℃; 1 or more than 1 spinneret orifices are distributed on the spinneret plate, and each spinneret orifice comprises an inner core with a concentric structure and an outer layer structure channel to form the spinneret plate with spinneret orifices with a composite structure; enabling the spinning solution A and the spinning solution B to pass through a spinneret plate, enabling the spinning solution A to be sprayed out from an inner core of a spinneret orifice, enabling the spinning solution B to be sprayed out from an outer layer of the spinneret orifice, and removing a volatile solvent in the solutions in a shaft drying process to obtain a fiber preform; and soaking the fiber preform in an alkali solution, drying, cooling and shaping to obtain the spandex fiber. The spandex with the controllable fiber cross-sectional shape has the advantages that the phenomenon of fiber cross-sectional shape change cannot occur in the process of removing the solvent from the channel, and the product S has excellent mechanical properties.)

1. A method for controlling the cross section shape of spandex fiber is characterized by comprising the following steps:

step 1, controlling the temperature of a polyurethane urea spinning solution A with the viscosity of 2000-5000 poise to be 50-80 ℃, and controlling the temperature of an alkali-soluble resin spinning solution B with the viscosity of 1000-6000 poise to be 60-120 ℃;

step 2, distributing 1 or more than 1 spinneret orifices on the spinneret plate, wherein the spinneret orifices comprise inner core and outer layer structural channels with concentric structures to form the spinneret plate with spinneret orifices of a composite structure;

step 3, enabling the spinning solution A and the spinning solution B to pass through a spinneret plate, enabling the spinning solution A to be sprayed out from an inner core of a spinneret orifice, enabling the spinning solution B to be sprayed out from an outer layer of the spinneret orifice, and removing a volatile solvent in the solution in shaft drying to obtain a fiber preform;

and 4, soaking the fiber preform in an alkali solution, drying, cooling and shaping to obtain the spandex fiber.

2. The method of claim 1, wherein the cross-sectional shape of the spandex fiber is controlled, and the inner diameter of a virtual circle tangent to the cross-sectional shape of the inner core of the spinneret orifice is 0.2-0.5 mm.

3. The method for controlling the cross-sectional shape of the spandex fiber according to claim 1, wherein the outer-layer structural channel of the spinneret hole is a channel with a circular cross-section, and the inner diameter of the cross-section of the outer layer is 0.7-22 mm.

4. The method of claim 1 or 2, wherein the ratio of the length of the outer layer structure channel of the spinneret orifice to the inner diameter of the virtual circle is 3-50.

5. The method for controlling the cross-sectional shape of the spandex fiber according to claim 1, wherein the thickness of the gap between the inner core and the outer layer structural channel is 0.15-11 mm.

6. The method of claim 1, wherein the center-to-center distance between adjacent orifices of the 1 or more orifices is 10 to 40 mm.

7. The method of claim 1, wherein the alkali-soluble resin is selected from one or more of polyethylene terephthalate resin having a molecular weight of 1000 to 6000, alkali-soluble polyacrylic resin having a molecular weight of 1000 to 6000, polyethylene isophthalate resin having a molecular weight of 1000 to 6000, and polypropylene isophthalate resin having a molecular weight of 1000 to 6000.

8. The method for controlling the cross-sectional shape of the spandex fiber according to claim 1 or 7, wherein the melting point of the alkali-soluble resin is 60 to 120 ℃.

9. The method of claim 1, wherein the volatile solvent is one or two of N, N-dimethylformamide and N, N-dimethylacetamide.

10. The method of claim 1, wherein the alkali solution is NaOH, KOH, Mg (OH) with a pH of 9-12₂、Ca(OH)₂One or more of aqueous solutions.

Technical Field

The invention relates to a method for controlling the cross section shape of spandex fibers, belonging to the technical field of polyurethane elastic fiber material manufacturing.

Background

Polyurethane elastic fibers (commonly known as "spandex") have found widespread use in textiles to impart excellent elasticity to fabrics. The production process of spandex mainly comprises 4 methods: dry spinning, wet spinning, melting spinning and reaction spinning, and the dry spinning has the advantages of less environmental pollution, low cost, excellent mechanical property of the yarn and the like, so that the dry spinning is the best process method for producing spandex, and more than 90% of spandex is produced by adopting the dry spinning method in the market. Because the spinning solution enters a high-temperature channel and undergoes solvent flash evaporation, the cross section of the spandex can deform under the hot air unilateral blowing for recovering the solvent, and the spandex takes on the shapes of peanut, ellipse and the like, and therefore, the patent report on the controllable cross section of the spandex fiber does not hear the taste.

The cross section shape of the fiber is very critical to the performance of spandex. The round section can endow the fiber with excellent wear resistance and mechanical property, the fiber with the cross section has better sweat absorption and discharge function, and the fiber with the triangular section has excellent light reflection performance, so that the development of the spandex with the controllable fiber section shape has profound significance for the development of functionalization and differentiation of the spandex.

In CN201780031288.0, Spandex in the shapes of peanut, circle, trilobal and the like is spun by adopting a dry spinning technology in non-circular solution spinning Spandex filament and a production method and device thereof, but in actual production, when a stock solution is extruded into a high-temperature channel and is transversely blown by hot air, a flash evaporation phenomenon occurs, a solvent DMAC is instantly taken away by the hot air, the cross section of the fiber is changed into the shape of peanut, and the triangle and the cross are difficult to prepare.

In CN201410407511.5, "a silk-like spandex fiber and its preparation method", a coagulation bath method is used to maintain the cross-sectional shape, but the DMAC cannot be removed in time by this method, which results in high residual rate of DMAC in spandex, poor mechanical properties, and low spinning speed. The dry spinning is adopted, and the air inlet temperature on a channel at 200-220 ℃ (the normal temperature is about 250 ℃), so that the residual rate is high and the mechanical property is poor. In short, the fiber section shape and mechanical property can not be ensured at the same time.

Disclosure of Invention

The technical problem is as follows: the invention aims to provide a method for controlling the cross section shape of a spandex fiber, which solves the problem that the cross section shape of the spandex fiber prepared by a dry spinning technology is uncontrollable.

The technical scheme is as follows: the method for controlling the cross section shape of the spandex fiber is realized by the following steps:

step 1, controlling the temperature of a polyurethane urea spinning solution A with the viscosity of 2000-5000 poise to be 50-80 ℃, and controlling the temperature of an alkali-soluble resin spinning solution B with the viscosity of 1000-6000 poise to be 60-120 ℃;

step 2, distributing 1 or more than 1 spinneret orifices on the spinneret plate, wherein the spinneret orifices comprise inner core and outer layer structural channels with concentric structures to form the spinneret plate with spinneret orifices of a composite structure;

step 3, enabling the spinning solution A and the spinning solution B to pass through a spinneret plate, enabling the spinning solution A to be sprayed out from an inner core of a spinneret orifice, enabling the spinning solution B to be sprayed out from an outer layer of the spinneret orifice, and removing a volatile solvent in the solution in shaft drying to obtain a fiber preform;

and 4, soaking the fiber preform in an alkali solution, drying, cooling and shaping to obtain the spandex fiber.

The spinneret orifice inner core is of a circular, triangular, rectangular or cross-shaped cross section, and the inner diameter of a virtual circle tangent to the cross section of the spinneret orifice inner core is 0.2-0.5 mm.

The spinneret orifice outer layer structure channel is a circular section channel, and the inner diameter of the outer layer section is 0.7-22 mm.

The ratio of the length of the outer layer structure channel of the spinneret orifice to the inner diameter of the virtual circle is 3-50.

The interval thickness of the inner core and the outer layer structure channel is 0.15-11 mm.

The center interval between adjacent spinneret orifices and the spinneret orifices of more than 1 spinneret orifice is 10-40 mm.

The alkali-soluble resin is selected from one or more of polyethylene terephthalate resin with the molecular weight of 1000-6000, alkali-soluble polyacrylic resin with the molecular weight of 1000-6000, polyethylene isophthalate resin with the molecular weight of 1000-6000 or polypropylene isophthalate resin with the molecular weight of 1000-6000.

The melting point of the alkali-soluble resin is 60-120 ℃.

The volatile solvent is one or two of N, N-dimethylformamide and N, N-dimethylacetamide.

The alkaline solution is NaOH, KOH or Mg (OH) with the PH of 9-12₂、Ca(OH)₂One or more of aqueous solutions.

Has the advantages that: according to the method for controlling the cross-sectional shape of the spandex fiber, provided by the invention, a dry spinning method is adopted, after alkali-soluble polyester and stock solution are introduced into a spinneret plate, a fiber preform is formed, and after polyester is dissolved out by alkali liquor, the spandex with the controllable cross-sectional shape is obtained, the phenomenon of fiber cross-sectional shape change cannot occur in the process of removing a solvent from a channel, and the mechanical property of the product is excellent.

Drawings

FIG. 1 is a schematic representation of the cross-section of the spinneret orifice of non-limiting example 1 of the present invention.

FIG. 2 is a schematic cross-sectional view of the spinneret orifices of non-limiting examples 2 and 3 of the present invention.

FIG. 3 is a schematic cross-sectional view of spandex fiber prepared in non-limiting example 1 of the present invention.

FIG. 4 is a microscopic cross-sectional view of a spandex fiber prepared in non-limiting example 2 of the present invention.

FIG. 5 is a cross-sectional microscopic enlarged view of spandex fiber prepared in comparative example 1 of the present invention.

FIG. 6 is a cross-sectional microscopic enlarged view of spandex fiber prepared in comparative example 2 of the present invention.

The figure shows that: the section of the outer layer of the spinneret orifice is 1, the section of the inner core of the spinneret orifice is 2, and the interval between the inner core and the outer layer is 3.

Detailed Description

The invention is described in detail below with reference to examples, which are not to be construed as limiting the invention in any way.

The polyurethane urea spinning solution A can be prepared by adopting a known polymerization reaction technology, for example, polyether polyol and excessive polyisocyanate are subjected to prepolymerization reaction to obtain prepolymer, a solvent is added into the prepolymer, and after the prepolymer is uniformly stirred, polyamine and/or monoamine are added to carry out chain extension reaction to obtain the polyurethane spinning solution A;

wherein, functional additives commonly used in the field can be further added into the polyurethane spinning solution A to improve physical properties, and the functional additives comprise: the additive amount of the functional additive has no special requirement, as long as the comprehensive performance and spinning performance of the polyurethane spinning solution A are not deteriorated;

the polyether polyol of the embodiment of the present invention, for example, one or more of polyoxyethylene glycol, polyoxypropylene glycol, polytetramethylene ether glycol, and polyoxypentamethylene glycol;

as an example, the polyether polyol is polytetramethylene ether glycol (PTMEG) with a hydroxyl value of between 30 and 120 mgKOH/g;

polyisocyanates according to embodiments of the present invention, for example, one or more of diphenylmethane diisocyanate, tolylene diisocyanate, m-and p-xylylene diisocyanate, tetramethyl-xylylene diisocyanate, diphenyl ether diisocyanate, dicyclohexyl diisocyanate, cyclohexylene diisocyanate, hexamethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, and isomers and derivatives thereof;

as an example, the polyisocyanate is a mixture of diphenylmethane diisocyanate and diphenylmethane diisocyanate dimer, the dimer being present in an amount of between 0.1 and 2% by weight;

polyamines of the embodiments of the present invention, for example, one or more of ethylenediamine, propylenediamine, hexamethylenediamine, and 2-methylpentanediamine;

monoamines of the embodiments of the present invention, for example, one or more of diethylamine, dipropylamine, ethanolamine, and n-hexylamine;

in some preferred embodiments of the present invention, the polyurethane spinning solution a preparing step comprises:

a prepolymerization step: using nitrogen gas N₂After the air in the reaction kettle is removed, slowly adding polyether polyol into the reaction kettle, starting the jacket water to circulate, keeping the water temperature at 30-60 ℃, starting stirring, slowly adding polyisocyanate, after the addition is finished, heating the jacket water to 70-100 ℃, and reacting for 2-8 hours to obtain prepolymer PP;

chain extension: introducing the PP into a high-speed rotator, introducing a solvent N, N-Dimethylacetamide (DMAC) at the temperature of 0-15 ℃, dissolving until the solution is clear and is not turbid, introducing the solution into a rotary reactor, adding polyamine and monoamine, and keeping the reaction temperature of the reactor at 60-100 ℃ for 15-600 s to obtain a POL stock solution;

curing step: and adding the functional auxiliary agent into the POL stock solution, stirring, and curing for 10-40 hr to obtain the polyurethane spinning solution A.

In some preferred embodiments of the invention, the alkali soluble resin spinning solution B is prepared by dissolving an alkali soluble resin in a solvent N, N-Dimethylacetamide (DMAC) at 60-120 ℃.

The invention discloses a method for controlling the cross section shape of spandex fiber, which is realized by the following steps:

controlling the temperature of a polyurethane urea spinning solution A with the viscosity of 2000-5000 poise to be 50-80 ℃, and controlling the temperature of an alkali-soluble resin spinning solution B with the viscosity of 1000-6000 poise to be 60-120 ℃;

enabling the spinning solution A and the spinning solution B to pass through a spinneret plate, and then removing a volatile solvent in the spinning solution A in a channel drying process to obtain a fiber preform;

soaking the fiber preform in an alkali solution, drying, cooling and shaping to obtain spandex fibers;

the melting point of the alkali-soluble resin is 60-120 ℃;

more than 1 spinneret orifice is distributed on the spinneret plate, and the spinneret orifice comprises a channel with a concentric structure to form an inner core and an outer layer structure;

the spinneret orifice inner core is more than one of a channel with a circular, triangular, rectangular and cross-shaped cross section, and the inner diameter of a virtual circle tangent to the section of the spinneret orifice inner core is 0.2-0.5 mm;

the outer layer of the spinneret orifice is a channel with a circular cross section, and the inner diameter of the cross section of the outer layer is 0.7-22 mm;

the ratio of the channel length of the spinneret orifice to the inner diameter of the virtual circle is 3-50;

the interval thickness between the inner core and the outer layer is 0.15-11 mm;

the center interval between the adjacent spinneret orifices is 10-40 mm;

in some embodiments of the invention, the spinneret orifice core is a triangular cross-section channel, and the inner diameter of a virtual circle tangent to the section of the spinneret orifice core is 0.2, 0.3, 0.4 or 0.5 mm;

in some embodiments of the invention, the outer layer of the spinneret orifice is a circular cross-section channel, and the cross section of the outer layer has an inner diameter of 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0 and 6.0 mm;

in some embodiments of the invention, the ratio of the channel length of the orifice to the inside diameter of said virtual circle is 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 30, 45, 50 mm;

in some embodiments of the present invention, the thickness of the space between the inner core and the outer layer is 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11mm.

In some embodiments of the invention, the center-to-center spacing between adjacent orifices is 10, 15, 20, 25, 30, 35, 40 mm;

in some embodiments of the present invention, the spinneret plate has 1 to 10 spinneret holes distributed thereon, for example: 1. 2, 3, 4, 5, 6, 8, 9 and 10 spinneret orifices.

Examples

Preparation of polyurethane spinning solution a:

a prepolymerization step: using nitrogen gas N₂After the air in the reaction kettle is removed, slowly adding 50kg of PTMG into the reaction kettle, starting the jacket water to circulate, keeping the water temperature at 30-60 ℃, starting stirring, slowly adding 12.3kg of MDI and MDI dimer, after the addition is finished, heating the jacket water to 90 ℃, and reacting for 6 hours to obtain a prepolymer PP;

chain extension: introducing the PP into a high-speed rotator, introducing 116.07kg of DMAC (dimethylacetamide) at the temperature of 10 ℃, dissolving until the solution is clear and is not turbid, introducing the solution into a rotary reactor, adding 1.171kg of polyamine (ethylenediamine, 1, 2-propanediamine and 2-methylpentanediamine) and 0.122kg of monoamine (diethylamine), and keeping the reaction temperature of the reactor at 90 ℃ for 300s to obtain a POL stock solution;

curing step: 2.875kg of functional assistant (antioxidant 1010: 0.536kg, chlorine-resistant assistant hydrotalcite 1.3kg, 1., lubricant magnesium stearate 0.87kg, and anti-ultraviolet assistant UV-531 0.169kg) was added to the POL stock solution, and the mixture was stirred and aged for 10 hours to obtain a polyurethane spinning solution A having a viscosity of 4200 poise.

Alkali soluble resin spinning solution B preparation:

dissolving polyethylene terephthalate resin with molecular weight of 1200 in DMAC at 80 ℃ to obtain an alkali soluble resin spinning solution B1;

dissolving polyethylene terephthalate resin with molecular weight of 1400 in DMAC at 82 deg.C to obtain alkali soluble resin spinning solution B2;

dissolving alkali soluble polyacrylic resin with molecular weight of 1000 in DMAC at 72 ℃ to obtain alkali soluble resin spinning solution B3;

example 1

Removing impurities from the polyurethane spinning solution A and the alkali-soluble resin spinning solution B1 through a filter, conveying the polyurethane spinning solution A and the alkali-soluble resin spinning solution B1 to a spinneret plate with 3 spinneret orifices through a pump, drying the polyurethane spinning solution A and the alkali-soluble resin spinning solution B through a channel at 258 ℃ to remove DMAC, soaking the polyurethane spinning solution A and the alkali-soluble resin spinning solution B in a high-temperature alkali solution pool at 86 ℃ for 150 seconds, drying the polyurethane spinning solution A and the alkali-soluble resin spinning solution B in hot air at 60 ℃, cooling;

the spinneret orifice inner core is of a cross-shaped cross section, and the inner diameter of a virtual circle tangent to the cross section of the spinneret orifice inner core is 0.4 mm;

the outer layer of the spinneret orifice is a channel with a circular section, and the inner diameter of the section of the outer layer is 0.8 mm;

the ratio of the channel length of the spinneret orifice to the inner diameter of the virtual circle is 15;

the interval thickness of the inner core and the outer layer is 0.2mm.

The center interval between the adjacent spinneret orifices is 30 mm;

the spinning solution A is sprayed out of the inner core of the spinneret orifice, and the spinning solution B is sprayed out of the outer layer of the spinneret orifice.

Example 2

Removing impurities from the polyurethane spinning solution A and the alkali-soluble resin spinning solution B2 through a filter, conveying the polyurethane spinning solution A and the alkali-soluble resin spinning solution B2 to a spinneret plate with 3 spinneret orifices through a pump, drying the polyurethane spinning solution A and the alkali-soluble resin spinning solution B through a channel at 258 ℃ to remove DMAC, soaking the polyurethane spinning solution A and the alkali-soluble resin spinning solution B in a high-temperature alkali solution pool at 86 ℃ for 180 seconds, drying the polyurethane spinning solution A and the alkali-soluble resin spinning solution B in hot air at 60 ℃, cooling;

the spinneret orifice inner core is a triangular section, and the inner diameter of a virtual circle tangent to the section of the spinneret orifice inner core is 0.4 mm;

the outer layer of the spinneret orifice is a circular section channel, and the inner diameter of the section of the outer layer is 0.8 mm;

the ratio of the channel length of the spinneret orifice to the inner diameter of the virtual circle is 15;

the interval thickness between the inner core and the outer layer is 0.2 mm;

the center interval between the adjacent spinneret orifices is 30 mm;

the spinning solution A is sprayed out of the inner core of the spinneret orifice, and the spinning solution B is sprayed out of the outer layer of the spinneret orifice.

Example 3

Removing impurities from the polyurethane spinning solution A and the alkali-soluble resin spinning solution B3 through a filter, conveying the polyurethane spinning solution A and the alkali-soluble resin spinning solution B3 to a spinneret plate with 3 spinneret holes through a pump, drying the polyurethane spinning solution A and the alkali-soluble resin spinning solution B through a channel at 258 ℃ to remove DMAC, soaking the polyurethane spinning solution A and the alkali-soluble resin spinning solution B in a high-temperature alkali solution pool at 86 ℃ for 60 seconds, drying the polyurethane spinning solution A and the alkali-soluble resin spinning solution B in hot air at 60 ℃;

the spinneret orifice inner core is a triangular section, and the inner diameter of a virtual circle tangent to the section of the spinneret orifice inner core is 0.4 mm;

the outer layer of the spinneret orifice is a circular section channel, and the inner diameter of the section of the outer layer is 0.8 mm;

the ratio of the channel length of the spinneret orifice to the inner diameter of the virtual circle is 15;

the interval thickness between the inner core and the outer layer is 0.2 mm;

the center interval between the adjacent spinneret orifices is 30 mm;

the spinning solution A is sprayed out of the inner core of the spinneret orifice, and the spinning solution B is sprayed out of the outer layer of the spinneret orifice.

Comparative example 1

And removing impurities from the polyurethane spinning solution A through a filter, conveying the polyurethane spinning solution A to a spinneret plate with 3 spinneret orifices through a pump, drying the polyurethane spinning solution A at 258 ℃ through a channel to remove DMAC, cooling and shaping the polyurethane spinning solution at 10 ℃ for 120s, and applying spinning oil to obtain the control spandex fiber 1.

The spinneret orifices are triangular in cross section, have no outer layer structure, and have an inner diameter of a virtual circle tangent to the cross section of the spinneret orifices of 0.4 mm;

the ratio of the channel length of the spinneret orifice to the inner diameter of the virtual circle is 15;

the center spacing between adjacent orifices was 30 mm.

Comparative example 2

Removing impurities from the polyurethane spinning solution A and the polyethylene glycol phthalate resin (molecular weight 1200) spinning solution B through a filter, conveying the polyurethane spinning solution A and the polyethylene glycol phthalate resin (molecular weight 1200) spinning solution B to a spinneret plate containing 3 spinneret orifices through a pump, drying the spinneret plate at 258 ℃ through a channel to remove DMAC, soaking the spinneret plate in a high-temperature alkali liquor pool for 300s at 86 ℃, drying the spinneret plate in hot air at 80 ℃, cooling and shaping the spinneret plate at 10 ℃ for 120s, and applying spinning oil to obtain a control spandex fiber 2;

the spinneret orifice inner core is of a cross-shaped cross section, and the inner diameter of a virtual circle tangent to the cross section of the spinneret orifice inner core is 0.4 mm;

the outer layer of the spinneret orifice is a circular section channel, and the inner diameter of the section of the outer layer is 0.8 mm;

the ratio of the channel length of the spinneret orifice to the inner diameter of the virtual circle is 15;

the interval thickness between the inner core and the outer layer is 0.2 mm;

the center interval between the adjacent spinneret orifices is 30 mm;

the spinning solution A is sprayed out of the inner core of the spinneret orifice, and the spinning solution B is sprayed out of the outer layer of the spinneret orifice.

Comparative example 3

Directly mixing the polyurethane spinning solution A and the alkali-soluble resin spinning solution B1 to obtain a spinning mixed solution, removing impurities through a filter, conveying the spinning mixed solution to a spinneret plate containing 3 spinneret orifices through a pump, drying the spinneret plate at 258 ℃ through a channel to remove DMAC, soaking the spinneret plate in a high-temperature alkali liquor pool for 150 seconds at 86 ℃, drying the spinneret plate in hot air at 80 ℃, cooling and shaping the spinneret plate at 10 ℃ for 120 seconds, and applying spinning oil to obtain a control spandex fiber 3;

the spinneret orifice inner core is a cross-shaped section, the spinneret orifice has no outer layer structure, and the inner diameter of a virtual circle tangent to the section is 0.4 mm;

the ratio of the length of the channel to the diameter of the inner core is 15;

the center spacing between adjacent orifices was 30 mm.

Table 1 is a table of the mechanical properties, moisture absorption and sweat releasing properties, color and luster degrees and other property data of examples 1 to 3 and comparative examples 1 to 3.

Table 1:

wherein SS300 is the stress at 300% draft; DS is the breaking strength and DE is the elongation at break; the wicking height is an index of moisture absorption and sweat releasing performance, spandex is woven according to the same specification and is vertically placed, the lower end of the spandex is immersed into blue dye liquor by 2cm, after the spandex is immersed for the same time, the rising height of the dye liquor is recorded and converted into the rising height of 30min, and experiments are carried out for 6 times; and delta b is a detection result of a colorimeter, and after spandex is woven in the experiment, the spandex is placed into blue dye to dye the sample with a negative delta b number which represents that the sample is blue, and a positive delta b number which represents that the sample is yellow.

From table 1, the spandex fiber obtained by the method of the invention has a good cross-section controllable effect, and the spandex fibers prepared in examples 1 to 3 can be respectively prepared into triangular and cruciform fibers, so that the moisture absorption effect is good. Comparative example 1 after the spinning solution was directly introduced into the triangular spinneret holes, an irregular peanut shape was finally obtained; the spinning solution of the comparative example 2 is introduced into a cross-shaped spinneret orifice to obtain a circular or irregular peanut shape; comparative example 3 a polyurethane spinning solution a and an alkali-soluble resin spinning solution B1 were directly mixed and spun, and then introduced into a cross-shaped spinneret orifice to obtain a porous circular or porous irregular peanut-shaped fiber. In the comparative examples described above, the cross section of the fibers after molding was deformed, for example, into a peanut shape or a circular shape, and it was difficult to obtain a desired triangular shape or a cruciform shape. In addition, compared with a comparative example, the fiber products of the examples have excellent mechanical data such as traction stress, breaking strength, elongation and the like, and after the spandex fibers are woven, the dyeing effect is obviously better than that of the comparative example.