Spandex spinning process and warp knitting eyelet fabric production process using spandex

Abstract

The invention relates to a spandex spinning process and a warp-knitted eyelet fabric production process applying spandex, which innovatively proposes that annular suction channels are introduced at the bottoms of spinneret orifices outside an existing lateral blowing mode, and the annular suction channels and conical nozzles at the bottoms of the spinneret orifices jointly form a Venturi effect. Air flow in an air blowing area on the upper portion of the spinning channel is adsorbed through the suction holes arranged in a surrounding mode to enter the annular suction channel, hot air and spinning fine liquid are made to move downwards in the axial direction, in the downward moving process, on one hand, all positions of the spinning fine liquid can be fully heated by the hot air, and the volatilization difference of solvents is effectively reduced; the spinneret plate is suitable for circular and various special-shaped sections, the coefficient of variation is reduced, the rebound resilience is improved, on the other hand, the requirement for spinneret orifice distribution is reduced, and the spinning speed is increased.

Description

Technical Field

[0001] The invention relates to the technical field of fabrics, and in particular to a spandex spinning process and a warp knitted mesh fabric production process using the spandex. Background Art

[0002] Spandex is widely used in textiles, giving fabrics excellent elasticity, such as sportswear, daily clothing and other elastic thin fabrics. The process of spandex spinning is as follows: the stock solution consisting of spandex, DMAC and other additives is filtered in the spinning assembly and distributed to the spinneret for spraying. The stock solution sprayed from the spinneret is evaporated by high-temperature hot air in the spinning tunnel to remove the DMAC solvent to obtain spandex tow.

[0003] There are two main methods of blowing hot air in the spinning tunnel. One is the side blowing method disclosed in the Chinese patent document (CN101235550A), in which the hot air is blown to the filament bundle perpendicular to the traveling direction of the filament bundle. The problem is that the windward side and the leeward side of the filament bundle are heated differently, the solvent evaporation rates on the windward side and the leeward side of the filament bundle are different, causing the filament bundle to be peanut or elliptical; the other is the annular blowing method disclosed in the Chinese patent document (CN1727529A), in which a single-circle annular blower is located on the periphery of the spinneret assembly, and the spinneret assembly is in the middle of the tunnel. The filament bundle extruded by the inner ring spinneret assembly is in direct contact with the hot air blown by the outer ring blower on the surface of the outer ring, resulting in different evaporation temperatures on the inner and outer ring surfaces of the filament bundle, different solvent evaporation rates, and poor performance. In addition, regarding the side-blowing type, the Chinese public patent document (CN204939668U) discloses distributing the spinneret holes on different cross-sections in the direction of the hot air, so that the ejected spinning liquids are not on the same blowing plane and are heated evenly. However, the distribution requirements for spinneret holes with a large number of holes are high, and the distribution space must be large enough, which will also affect the diffusion and convection of the hot air inside the spinning channel, and there are still large differences in the volatilization of the solvent in the fiber bundles. Summary of the invention

[0004] The purpose of the present invention is to provide a spandex spinning process and a warp knitted mesh fabric production process using spandex, which, on the one hand, reduces the requirements for the distribution of spinneret holes, and on the other hand, enables hot air to flow along the direction of the spinning liquid, so that each spinning liquid can be fully heated, effectively reducing the volatilization difference, and at the same time helps to increase the spinning speed and improve the mechanical properties of the spandex yarn.

[0005] To achieve the above object, the technical solution adopted by the present invention is: The spandex spinning process specifically includes the following steps: S1, preparing spandex spinning solution with a viscosity of 500Pa•S-700Pa•S; S2, the spandex spinning stock solution of step S1 is sprayed out from the spinneret into the spinning tunnel after filtering, degassing, mixing and metering, the spinning fine solution removes the volatile solvent in the spinning tunnel, and then is output from the spinning tunnel for false twisting, oiling, thread guiding and winding to obtain spandex yarn; Wherein: in step S2, air is blown to the upper part of the spinning tunnel through the upper air inlet, and the airflow of the upper air inlet is adsorbed through the annular suction channel installed at the bottom of each spinneret hole, so that the airflow and the spinning liquid are mixed and convected in the annular suction channel and move axially downward, and finally the air is returned through the annular return air mechanism at the lower part of the spinning tunnel to recover the solvent.

[0006] Preferably, the spinneret holes of the spinneret plate are of special shape, and the number of the spinneret holes is 28.

[0007] Preferably, the spinneret holes are four-lobed.

[0008] Preferably, the preparation process of the spandex spinning stock solution comprises reacting polyglycol, n-butanol and diisocyanate in DMAC (N,N-dimethylacetamide) to obtain a prepolymer solution, adding a DMAC solution containing an amine chain extender and a monoamine terminator to the cooled prepolymer solution for chain extension reaction to obtain a copolymer solution, and adding a functional additive to mix to obtain the spandex spinning stock solution.

[0009] Preferably, the amine chain extender is ethylenediamine and / or 1,2-propylenediamine, the monoamine terminator is diethylamine, the polyglycol is PTMG (polytetramethylene glycol), and the diisocyanate is MDI (diphenylmethane diisocyanate).

[0010] Preferably, the spinning tunnel is provided with a side-blowing mechanism located at the upper part of the spinning tunnel and a circular return air mechanism located at the lower part of the spinning tunnel, and a conical nozzle with a gradually decreasing inner diameter and an annular suction channel which wraps the conical nozzle and extends axially along the spinning tunnel are respectively installed at the bottom of each spinneret hole, and the interior of the annular suction channel is successively arranged as a suction chamber and a diffusion chamber from top to bottom, and the suction chamber is composed of a cylindrical upper chamber which is coaxially connected up and down and a conical lower chamber with a gradually decreasing inner diameter, and a plurality of suction holes which are connected to the blowing area of ​​the side-blowing mechanism are arranged around the side wall of the cylindrical upper chamber, and the diffusion chamber is a conical chamber with a gradually increasing inner diameter, and the conical nozzle extends into the suction chamber.

[0011] Preferably, the air outlet temperature at the bottom of the annular suction channel is 140°C-150°C.

[0012] Preferably, the temperature of the upper inlet air is 240° C.-260° C., the wind speed is 0.4 m / s-0.6 m / s, and the spinning speed is 500 m / min-800 m / min.

[0013] The present invention also provides a production process for warp knitted mesh cloth using spandex, wherein spandex yarn and nylon filaments obtained by the above-mentioned spandex spinning process are used as raw yarns for warp knitting to obtain nylon-spandex grey cloth, the density on the machine is controlled at 50-55 horizontal rows per centimeter, the width on the machine is 210cm±2.5cm and is finalized to an effective width of 125±2.5cm in the later stage, and the yarn feeding amount of the nylon filaments is controlled at 740mm / R-900mm / R.

[0014] Wherein: the spandex yarn is 210D / 28F, and the inlay yarn numbers of the two spandex combs are 1-1 / 0-0 / 0-0 / 1-1 / / and 0-0 / 1-1 / 1-1 / 0-0 / / ; the nylon filament is 24D / 7F, and the inlay yarn numbers of the two combs are 1-0 / 1-2 / 2-3 / 2-1 / / and 2-3 / 2-1 / 1-0 / 1-2 / / .

[0015] Compared with the prior art, the present invention has the following beneficial effects: In order to solve the problems of large differences in heating and solvent volatilization of the spinning tunnel in the prior art for multi-hole spinning, the present invention innovatively proposes to introduce an annular suction channel at the bottom of each spinneret while retaining the existing side blowing mode. The annular suction channel and the conical nozzle at the bottom of the spinneret together constitute a Venturi effect. The surrounding suction holes are used to absorb the wind flow in the upper blowing area of ​​the spinning tunnel into the annular suction channel, and the hot air and the spinning liquid are made to move downward along the axial direction. During the downward process, on the one hand, each spinning liquid at each position can be fully heated by the hot air, which effectively reduces the difference in solvent volatilization. It is suitable for circular and various special-shaped sections, reduces the coefficient of variation, and improves the resilience. On the other hand, it reduces the requirements for the distribution of spinneret holes, which helps to increase the spinning speed.

[0016] The warp knitted mesh fabric of the present invention selects 210D / 28F spandex and controls the on-machine density and the yarn feeding amount of the nylon filaments, so that the fabric structure is stable, not easy to deform, not easy to fall apart, and has strong elasticity. Moreover, the greater the on-machine density of the fabric, the tighter the nylon filaments, and the less likely the spandex is to burst, thereby avoiding the risk of spandex bursting to a great extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the spinning tunnel of the present invention.

[0018] Figure 2 for Figure 1 A is a partial enlarged view shown in FIG.

[0019] Figure 3 This is a motion diagram of the warp knitted mesh inlay yarn of the present invention. DETAILED DESCRIPTION

[0020] In order to make the above features and advantages of the present invention more obvious and easy to understand, embodiments are given below with reference to the accompanying drawings for detailed description as follows. Example 1

[0021] like Figure 1 As shown, this embodiment provides a spandex spinning process, which specifically includes the following steps: S1. Preparation of spandex spinning stock solution: first, 385 kg of polydiol PTMG with a molecular weight of 3497 is reacted with 115.5 g of n-butanol and 50.9 kg of diisocyanate MDI in 701.5 kg of DMAC to obtain a prepolymer solution, and then a DMAC solution containing 5 kg of ethylenediamine, 1.1 kg of 1,2-propylenediamine and 1.1 kg of diethylamine is added to the cooled prepolymer solution for chain extension reaction to obtain a copolymer solution, and then an appropriate amount of functional additives are added and mixed to obtain a spandex spinning stock solution, wherein the functional additives are anti-ultraviolet agents and antioxidants, and the viscosity is 600 Pa•S.

[0022] S2, the spandex spinning stock solution of step S1 is sprayed out from the spinneret into the spinning tunnel after filtering, degassing, mixing and metering, the spinning fine solution removes the volatile solvent in the spinning tunnel, and then is output from the spinning tunnel for false twisting, oiling, thread guiding and winding to obtain spandex yarn 210D / 28F.

[0023] Wherein: in step S2, the number of spinneret holes of the spinneret plate is 28, all of which are four-lobed, and the cross-sectional shape of the obtained monofilament is four-lobed.

[0024] In this embodiment, the spinning tunnel is provided with a side-blowing mechanism 10 located at the upper part of the spinning tunnel and a circulating return air mechanism 20 located at the lower part of the spinning tunnel. The side-blowing mechanism 10 includes an air inlet chamber and a return air chamber arranged opposite to each other. The air inlet chamber and the return air chamber are respectively provided with rectifying components. This is conventional technology and will not be described in detail. The circulating return air mechanism 20 is also a conventional return air structure in the spinning tunnel in the prior art.

[0025] In this embodiment, the upper air intake is blown toward the upper part of the spinning tunnel through the air intake chamber and a blowing area is formed in the upper part of the spinning tunnel. After the air flows through the blowing area, a part of it is recovered from the return air chamber and a part of it is adsorbed by the circular suction channel 30 and enters the circular suction channel 30 corresponding to each spinneret hole, and then returns to the spinning tunnel from the bottom of the circular suction channel 30 and returns the air and recovers the solvent from the lower circular return air mechanism 20. The spinning speed is 500m / min, the temperature of the upper air intake is 258°C, the wind speed is 0.5m / s, and the air outlet temperature at the bottom of the circular suction channel 30 is 145°C.

[0026] The bottom of each spinneret hole in the present embodiment is respectively provided with a conical nozzle 40 with a gradually decreasing inner diameter and an annular suction channel 30 which wraps the conical nozzle 40 and extends axially along the spinning tunnel. The interior of the annular suction channel 30 is successively provided with a suction chamber 31 and a diffusion chamber 32 from top to bottom. The suction chamber 31 is composed of a cylindrical upper chamber and a conical lower chamber with a gradually decreasing inner diameter which are coaxially connected up and down. The side wall of the cylindrical upper chamber is surrounded by a plurality of suction holes 33 which are connected to the blowing area of ​​the side blowing mechanism 10. The diffusion chamber 32 is a conical chamber with a gradually increasing inner diameter. The conical nozzle 40 extends into the suction chamber 31. The spinning liquid is ejected from the conical nozzle 40 at a high speed and is accelerated and forms a negative pressure suction after passing through the suction chamber 31. The airflow of the upper wind is absorbed by the annular suction channel 30, so that the airflow and the spinning liquid are mixed and convected in the annular suction channel 30 and move axially downward. At this time, the direction of the wind flow is the same as that of the spinning liquid and the contact time is sufficient. The total length of the annular suction channel 30 is 2 meters.

[0027] The elongation at break of the spandex measured by FZ / T 50006-2013 was 648%, and the coefficient of variation was 0.9. The 300% elastic recovery rate of the spandex measured by FZ / T 50007-2012 was 94.2%. Example 2

[0028] The present embodiment provides a production process for warp knitted mesh fabric using spandex, wherein the spandex yarn 210D / 28F (B yarn) and nylon filament 24D / 7F (A yarn) prepared in Example 1 are used as raw yarns to be knitted on a 32-needle RSE4 warp knitting high-speed machine to obtain a nylon-spandex grey fabric, and the density on the machine is controlled at 50-55 horizontal rows per centimeter, so that the elongation of the fabric becomes shorter (under the same conditions, the greater the density on the machine, the shorter the elongation of the fabric, but the firmness and structural stability of the fabric are stronger), and then the fabric uses 210D spandex, and the spandex accounts for a large proportion, which greatly enhances the warp elasticity of the fabric.

[0029] As shown in the figure, nylon filament uses two combs, one with one threaded and one empty, the other with one empty and one threaded, and the inlay yarn numbers are 1-0 / 1-2 / 2-3 / 2-1 / / and 2-3 / 2-1 / 1-0 / 1-2 / / . Spandex yarn uses two combs, one with one threaded and one empty, the other with one empty and one threaded, and the inlay yarn numbers are 1-1 / 0-0 / 0-0 / 1-1 / / and 0-0 / 1-1 / 1-1 / 0-0 / / .

[0030] The width on the machine is 210cm±2.5cm and is finalized to an effective width of 125±2.5cm in the later stage. The shrinkage amplitude becomes larger, so the finished fabric also has strong weft elasticity. The yarn feeding amount of nylon filament is controlled at 740mm / R-900mm / R, which makes the nylon filament more compact when looped, and can play the effect of not being easy to pull apart and not being easy to fall apart after washing.

[0031] In order to increase the shrinkage of fabric setting, the washing speed should be reduced as much as possible during the degreasing stage before dyeing and finishing to ensure that the fabric shrinks fully in hot water. The washing speed is 15 m / min and the water temperature is not less than 95°C. The time in hot water is not less than 60 minutes. In the pre-setting stage, the overfeeding process is used to relax the fabric and ensure that the fabric has enough shrinkage space in the setting oven. The setting temperature is not less than 195°C.

[0032] The weft elongation of the fabric tested using the FZ / T 70006-2004 standard (constant load 30N) was found to be 156.4%.

[0033] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention shall be defined by the attached claims and their equivalents.

Claims

1. A spandex spinning process, characterized in that: The specific steps include: S1, preparing spandex spinning solution with a viscosity of 500Pa•S-700Pa•S; S2, the spandex spinning stock solution of step S1 is sprayed out from the spinneret into the spinning tunnel after filtering, degassing, mixing and metering, the spinning fine solution removes the volatile solvent in the spinning tunnel, and then is output from the spinning tunnel for false twisting, oiling, thread guiding and winding to obtain spandex yarn; Wherein: in step S2, air is blown to the upper part of the spinning tunnel through the upper air inlet, and the airflow of the upper air inlet is adsorbed through the annular suction channel installed at the bottom of each spinneret hole, so that the airflow and the spinning liquid are mixed and convected in the annular suction channel and move axially downward, and finally the air is returned through the annular return air mechanism at the lower part of the spinning tunnel to recover the solvent.

2. The spandex spinning process according to claim 1, characterized in that: The spinneret holes of the spinneret plate are of special shape, and the number of the spinneret holes is 28.

3. The spandex spinning process according to claim 2, characterized in that: The spinneret hole is a four-leaf type.

4. The spandex spinning process according to claim 1, characterized in that: The preparation process of the spandex spinning stock solution comprises reacting polydiol, n-butanol and diisocyanate in DMAC to obtain a prepolymer solution, adding a DMAC solution containing an amine chain extender and a monoamine terminator to the cooled prepolymer solution to carry out a chain extension reaction to obtain a copolymer solution, and adding a functional additive to mix to obtain the spandex spinning stock solution.

5. The spandex spinning process according to claim 4, characterized in that: The amine chain extender is ethylenediamine and / or 1,2-propylenediamine, the monoamine terminator is diethylamine, the polyglycol is PTMG, and the diisocyanate is MDI.

6. The spandex spinning process according to claim 1, characterized in that: The spinning tunnel is provided with a side-blowing mechanism located at the upper part of the spinning tunnel and a circular return air mechanism located at the lower part of the spinning tunnel, and a conical nozzle with a gradually decreasing inner diameter and an annular suction channel which wraps the conical nozzle and extends axially along the spinning tunnel are respectively installed at the bottom of each spinneret hole, and the interior of the annular suction channel is successively arranged as a suction chamber and a diffusion chamber from top to bottom, and the suction chamber is composed of a cylindrical upper chamber coaxially connected up and down and a conical lower chamber with a gradually decreasing inner diameter, and a plurality of suction holes connected to the blowing area of ​​the side-blowing mechanism are arranged around the side wall of the cylindrical upper chamber, and the diffusion chamber is a conical chamber with a gradually increasing inner diameter, and the conical nozzle extends into the suction chamber.

7. The spandex spinning process according to claim 6, characterized in that: The air outlet temperature at the bottom of the annular suction channel is 140°C-150°C.

8. The spandex spinning process according to claim 1, characterized in that: The temperature of the upper inlet air is 240° C.-260° C., the wind speed is 0.4 m / s-0.6 m / s, and the spinning speed is 500 m / min-800 m / min.

9. The production process of warp knitted mesh fabric using spandex is characterized by: The nylon-spandex grey cloth is obtained by knitting the spandex yarn and nylon filament obtained by the spandex spinning process as described in any one of claims 1 to 8 as raw yarns, the density on the machine is controlled at 50-55 horizontal rows per centimeter, the width on the machine is 210cm±2.5cm and is finalized to an effective width of 125±2.5cm in the later stage, and the yarn feeding amount of the nylon filament is controlled at 740mm / R-900mm / R.

10. The production process of warp knitted mesh fabric using spandex according to claim 9, characterized in that: The spandex yarn is 210D / 28F, and the inlay yarn numbers of the two spandex combs are 1-1 / 0-0 / 0-0 / 1-1 / / and 0-0 / 1-1 / 1-1 / 0-0 / / ; the nylon filament is 24D / 7F, and the inlay yarn numbers of the two combs are 1-0 / 1-2 / 2-3 / 2-1 / / and 2-3 / 2-1 / 1-0 / 1-2 / / .

Images