Preparation method of cloud hemp thread for breathable fabric

Abstract

The invention belongs to the technical field of textile, and particularly relates to a preparation method of cloud hemp yarn for breathable fabric, tows sequentially pass through a first oiling device, a pre-interlacer, a first yarn guide roller, a first hot roller, a second hot roller, a third hot roller, a fourth hot roller, a second oiling device, a second yarn guide roller, a main interlacer, a third yarn guide roller and a winding device; the roughness of the circumferential surface of the first godet is uniform, and the value range is 1.3-1.5 microns; the peripheral surfaces of the first hot roller and the second hot roller are divided into two parts which are symmetrically distributed along the central axes of the first hot roller and the second hot roller respectively, the roughness of one part is 0.1-0.15 mu m, and the roughness of the other part is 1.3-1.5 mu m. According to the invention, the number of winding turns is not changed, and only the roughness of the first godet, the roughness of the first hot roller and the roughness of the second hot roller are changed, so that the irregular bamboo joint effect of the cloud hemp thread for the breathable fabric is effectively improved, and meanwhile, broken filaments and broken ends are reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of textiles, and particularly relates to a preparation method of cloud bamboo silk for air-permeable fabric. BACKGROUND

[0002] Air-permeable fabric plays an important role in daily wear, which can ensure comfort in hot seasons or during high-intensity activities. Cloud bamboo silk is bamboo slubbing with irregular changes in node length and pitch. Slubbing is a kind of filament yarn with various changes in thickness, crystal orientation, dyeing depth, boiling water shrinkage, initial modulus and other characteristics in the length direction. Due to the irregular slubbing effect of cloud bamboo silk, air-permeable fabric woven from cloud bamboo silk is more popular with consumers. Therefore, it is of great significance to study the preparation method of cloud bamboo silk for air-permeable fabric.

[0003] A patent with the authorized announcement number CN101748502B discloses an FDY polyester bamboo slubbing and a preparation method thereof. The patent adopts an FDY process, the stretching speed is 2800-3200 m / min, the stretching pre-network pressure is 0.22 MPa, the stretching multiple is 1.9-2.2, the hot roller speeds GR1 / GR2 are 1400-1600 m / min and 2800-3200 m / min respectively, the hot roller temperatures GR1 / GR2 are 65-75 DEG C and 108-118 DEG C respectively, and the irregular slubbing effect is realized by reducing the number of winding turns and making the slubbing slip on the hot roller.

[0004] However, the technical solution disclosed in CN101748502B still has the following disadvantages: in order to realize the stretching of the slubbing before it is completely heated, the first hot roller has a low temperature, and then a small number of winding turns are adopted, which is prone to cause problems such as fluff and broken ends, and even cannot be wound into a shape, which is also not conducive to improving the irregular slubbing effect.

[0005] Therefore, there is an urgent need for a preparation method of cloud bamboo silk for air-permeable fabric, which can effectively improve the irregular slubbing effect and reduce fluff and broken ends. SUMMARY

[0006] The application aims to solve the above problems in the prior art and provide a preparation method of cloud bamboo silk for air-permeable fabric.

[0007] To achieve the above objective, the technical scheme adopted by the application is as follows:

[0008] A preparation method of cloud bamboo silk (i.e. bamboo slubbing with irregular changes in node length and pitch) for air-permeable fabric, wherein the slubbing sequentially passes through a first oiling device, a pre-networker, a first godet roller, a first hot roller, a second hot roller, a third hot roller, a fourth hot roller, a second oiling device, a second godet roller, a main networker, a third godet roller and a winding device.

[0009] The roughness of the peripheral surface of the first godet is uniform, and the value range is 1.3-1.5 μm;

[0010] The peripheral surface of the first heat roller is divided into two parts which are symmetrically distributed along the central axis of the first heat roller, the roughness of one part is 0.1-0.15 μm, and the roughness of the other part is 1.3-1.5 μm;

[0011] The peripheral surface of the second heat roller is divided into two parts which are symmetrically distributed along the central axis of the second heat roller, the roughness of one part is 0.1-0.15 μm, and the roughness of the other part is 1.3-1.5 μm;

[0012] The roughness of the peripheral surface of the third heat roller is uniform, and the value range is 0.30-0.35 μm;

[0013] The roughness of the peripheral surface of the fourth heat roller is uniform, and the value range is 0.30-0.35 μm;

[0014] The winding number of the tow in the first heat roller to the fourth heat roller is 0.5 turns;

[0015] The roughness of the peripheral surface of the second godet and the third godet is uniform, and the value range is 1.3-1.5 μm;

[0016] The first godet, the first heat roller, the second heat roller, the third heat roller, the fourth heat roller, the second godet and the third godet are all cylindrical structures, the diameter of the first to the third godets is 110 mm, and the diameter of the first to the fourth heat rollers is 220 mm.

[0017] As a preferred technical scheme:

[0018] The preparation method of the cloud hemp yarn for the breathable fabric as described above, the first oiling device is an oil nozzle;

[0019] The air pressure of the pre-networker is 0.38-0.45 MPa;

[0020] The pre-networker is an equal-section vertical plate, which is provided with a horizontal air flow jet hole, a certain cross section of the pre-networker passes through the air flow jet hole, the cross section is an Archimedes spiral, the polar angle of the Archimedes spiral is ≥ 360° and ≤ 450°, the air flow jet hole is located at the position of the Archimedes spiral with a polar angle of 180°, and the air flow jet hole faces the center of the Archimedes spiral;

[0021] The guide wire hooks at the inlet and outlet of the pre-networker are groove-shaped guide wire hooks, which are composed of a U-shaped guide wire hook and a limiting block, the U-shaped guide wire hook is horizontally arranged, the limiting block is connected with the inner wall of the U-shaped guide wire hook, and is used for limiting the fiber bundle in the bottom area of the U-shaped guide wire hook; the fiber bundle sequentially passes through the bottom area of the groove-shaped guide wire hook located above, the central position of the pre-networker and the bottom area of the groove-shaped guide wire hook located below from top to bottom.

[0022] The air pressure of the pre-networker is set to 0.38-0.45 MPa (significantly higher than the air pressure 2.8-3.0 kgf / cm 2 ) of the patent application with the publication number CN109594137A, so that the firmness and density of the network points can be increased, and the density of the slubs can be improved; in order to avoid the problems of hairiness, broken ends, uneven network points and incomplete head formation caused by the increase of the air pressure of the pre-networker, the oiling method of CN109594137A is changed from oil wheel oiling to oil nozzle oiling, the pre-networker of CN109594137A is replaced by a pre-networker with an Archimedes spiral structure, and the U-shaped guide wire hooks before and after the pre-networker of CN109594137A are replaced by groove-shaped guide wire hooks, which are specifically described as follows:

[0023] The oil nozzle oiling is adopted, after the fiber bundle enters the oil channel of the oil nozzle, the oil agent is sprayed from the oil injection hole of the oil nozzle to oil the fiber bundle, and the single filaments of the oiled fiber bundle also have good mutual adhesion, so that the fiber bundle can be gathered, and the gathering distance is reduced compared with CN109594137A;

[0024] The pre-networker with the Archimedes spiral structure is adopted, the inner chamber thereof is a relatively closed structure, can lock the fiber bundle so that it cannot jump out of the pre-networker, and can optimize the stress points of the fiber bundle after entering the pre-networker, so that the single filaments of the fiber bundle have better cohesion in the pre-networker, the network points are ensured, the airflow in the pre-networker can be discharged after rotation, the air pressure in the inner chamber of the pre-networker is more stable, the fiber bundle is not easy to rub against the edge of the pre-networker, and the generation of hairiness and broken ends is reduced, and the breaking strength of the fiber bundle is improved;

[0025] The fiber bundle is fixed at the middle position of the pre-networker by the two groove-shaped guide wire hooks, so that the stress points of the fiber bundle after entering the pre-networker are more consistent, if the conventional U-shaped guide wire hook (its cross section is shown as Figure 3 a) is used, the fiber bundle cannot be fixed at the middle position of the pre-networker due to the large angle of the fiber bundle before and after the pre-networker, and the stress points are inconsistent, and the network points are uneven.

[0026] The preparation method of the cloud hemp yarn for the air-permeable fabric as described above, the Archimedes helix coefficient of the Archimedes helix is 1-2 mm / °, the polar radius when the polar angle is 0° is 1.5-2 mm; the airflow injection hole is a circular hole with a diameter of 1.1-1.3 mm, and the airflow injection hole is located at the middle position of the pre-networker along the vertical direction; the distance between each groove-shaped guide hook and the pre-networker along the vertical direction is 13-17 mm; the angle α between the yarn and the vertical direction at the groove-shaped guide hook located above is 5-10°; and the angle β between the yarn and the vertical direction at the groove-shaped guide hook located below is 5-10°.

[0027] The preparation method of the cloud hemp yarn for the air-permeable fabric as described above, the distance between each groove-shaped guide hook and the pre-networker along the vertical direction is 13-17 mm; the angle α between the yarn and the vertical direction at the groove-shaped guide hook located above is 5-10°; and the angle β between the yarn and the vertical direction at the groove-shaped guide hook located below is 5-10°.

[0028] The preparation method of the cloud hemp yarn for the air-permeable fabric as described above, the airflow injection hole of each pre-networker of each spinning position is communicated with a branch pipe, all the branch pipes are communicated with the same main pipe, and an automatic pressure regulating valve is arranged on the air inlet end of the main pipe.

[0029] The preparation method of the cloud hemp yarn for the air-permeable fabric as described above, the linear speed of the first guide roller is 1580-1600 m / min, the temperature of the first heat roller is 50-60 ℃, the linear speed of the first heat roller is 1590-1610 m / min, the temperature of the second heat roller is 50-60 ℃, the linear speed of the second heat roller is 1690-1710 m / min, the temperature of the third heat roller is 100-110 ℃, the linear speed of the third heat roller is 3100-3200 m / min, the temperature of the fourth heat roller is 100-110 ℃, the linear speed of the fourth heat roller is 3100-3200 m / min, the linear speed of the second guide roller is 3110-3210 m / min, the linear speed of the third guide roller is 3125-3225 m / min, and the winding speed of the winding device is 3175-3275 m / min.

[0030] The preparation method of the cloud hemp yarn for the air-permeable fabric as described above, the air pressure of the main networker is 0.38-0.42 MPa; the first oiling device adopts crude oil oiling, and the oiling rate is 0.4-0.5%; the second oiling device adopts oiling with an oil agent with a concentration of 19.5-20.5 wt% (the mass percentage of the mass of the oil agent in the total mass of the oil agent and water), and the oiling rate is 0.5-0.6%; and the conventional process route is to perform oiling once after drafting and setting, but due to the high air pressure of the pre-networker, if the yarn is not oiled after cooling, hairiness is prone to occur, so the present application increases the oiling once in the spinning section.

[0031] The preparation method of the breathable fabric cloud hemp yarn as claimed in any one of the above, the yarn contains 0.21-0.24wt% of the matting agent, and the specification of the yarn is 50-61dtex / 24f.

[0032] The preparation method of the breathable fabric cloud hemp yarn as claimed in any one of the above, the yarn has a CV value of 13.5-15.6% of the unevenness of the strip (reflecting the performance index of the unevenness and irregularity of the local thickness of the breathable fabric cloud hemp yarn), a kink density of 26-30 / m, an elongation at break of 84.8-85.7%, a breaking strength of 3.45-3.61cN / dtex, a boiling water shrinkage of 34.1-36.5%, a maximum kink length before the boiling water shrinkage test of 0.43-0.71cm, a maximum kink length after the boiling water shrinkage test of 0.28-0.46cm, a downgrading rate of ≤0.05%, a number of breakages of ≤5.3 times / 18 positions·24 hours, and a network deviation of ≤3 / m.

[0033] Advantages:

[0034] (1) The present application does not change the number of winding turns, but only changes the roughness of the first godet, the roughness of the first hot roller and the roughness of the second hot roller to adjust the holding force of the yarn on the surface, form a drafting slip, and realize the irregular kink effect of the yarn through the change of the drafting.

[0035] (2) In the drafting slip, the present application affects the spinning tension through the roughness of the first godet, so that the fiber crystallization in the spinning stage appears irregularity, and the irregular kink effect of the yarn is better.

[0036] (3) The roughness of the two halves of the first hot roller and the second hot roller of the present application is different, and the heating efficiency is also different, and the irregular kink effect of the yarn is further improved through the change of the heating efficiency.

[0037] (4) The present application changes the surface roughness of the first godet, the first hot roller and the second hot roller to adjust the holding force of the yarn on the first godet, the first hot roller and the second hot roller, which can reduce the number of breakages during the drafting process.

[0038] (5) The present application changes the surface roughness of the first godet, the first hot roller and the second hot roller to adjust the contact area of the yarn on the first hot roller and the second hot roller, and further adjust the heating efficiency of the yarn on the first hot roller and the second hot roller, so as to avoid cold stretching and reduce the number of down. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 It is a schematic diagram of the preparation device of the breathable fabric cloud hemp yarn of the present application;

[0040] Figure 2Fig. 1 is a schematic diagram of the pre-networker of the present application, and the dotted line circle in the figure is the air flow nozzle of the pre-networker;

[0041] Figure 3 Fig. 1 is a schematic diagram of the pre-networker of the present application, and the dotted line circle in the figure is the air flow nozzle of the pre-networker;

[0042] Figure 4 Fig. 1 is a schematic diagram of the pre-networker of the present application, and the dotted line circle in the figure is the air flow nozzle of the pre-networker;

[0043] In the figure, 1 is a first oiling device, 2 is a pre-networker, 3 is a first godet, 4 is a first heating roller, 5 is a second heating roller, 6 is a third heating roller, 7 is a fourth heating roller, 8 is a second oiling device, 9 is a second godet, 10 is a main networker, 11 is a third godet, 12 is a winding device, 13 is a filament bundle, 14 is a U-shaped guide hook, 15 is a limiting block, 16 is an upper recess-shaped guide hook, and 17 is a lower recess-shaped guide hook. DETAILED DESCRIPTION

[0044] The present application will be further described in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application. Furthermore, it should be understood that those skilled in the art can make various modifications or changes to the present application after reading the content taught by the present application, and these equivalent forms also fall within the scope defined by the claims attached hereto.

[0045] The following are the test methods of the relevant performance indicators in each example and comparative example:

[0046] (1)Bunch density: The number of bunches per meter of the filament bundle is observed by appearance.

[0047] (2)Breaking strength and breaking elongation: Referring to GB / T 14344-2022 “Chemical fiber filament tensile property test method”, the sample is measured by using a full-automatic single yarn strength machine (model YG023B-II), and the specific process is as follows: first, the sample is placed in an environment with a temperature of 20℃ and a relative humidity of 65% for 4h for moisture conditioning, then the sample is clamped by upper and lower clamps, the clamping length is 500mm, and a pre-tension of 0.05cN / dtex is applied by a mechanical hand to stabilize the sample, when starting the test, the lower clamp uniformly stretches the sample at a speed of 500mm / min, until the sample is broken, and the real-time data of the force sensor during the stretching process is recorded, and the relationship curve between the strength and the elongation is drawn by a data collection system, and finally the breaking strength and the breaking elongation of the sample are obtained by data processing analysis.

[0048] (3) Boiling water shrinkage: The boiling water shrinkage of the sample was tested by the skein method according to the standard of GB / T 6505-2017 "Chemical fiber filament heat shrinkage test method (after treatment)", the sample was treated by boiling water, and the sample length before boiling water treatment and the sample length after boiling water treatment were measured, and the calculation formula of the boiling water shrinkage was as follows:

[0049] Boiling water shrinkage = (sample length before boiling water treatment - sample length after boiling water treatment) / sample length before boiling water treatment x 100%.

[0050] (4) Maximum kink length before boiling water shrinkage test: The maximum kink length within 1 meter was measured by a ruler.

[0051] (5) Maximum kink length after boiling water shrinkage test: After the boiling water shrinkage test, the maximum kink length within 1 meter was measured by a ruler.

[0052] (6) Downgrade rate of fluff: The downgrade of the silk cake was determined according to whether the number of broken filaments on the surface exceeded 2, and the downgrade of the fluff was then obtained by the calculation formula, and the calculation formula was: Downgrade rate of fluff = (number of fluff downgrade / total number) x 100%.

[0053] (7) Number of broken ends: Broken end refers to the sudden breaking of a single filament during spinning, and 1 broken end is counted as 1 time, and the number of broken ends per 18 positions per 24 hours is calculated based on the average value in a 10-day 18-position statistical cycle.

[0054] (8) Network degree deviation: Network degree deviation = |measured network degree - network degree standard value|, the measured network degree was tested according to FZ / T 50001-2016 "Synthetic fiber filament network degree test method manual needle moving method", and the specific process was as follows: the sample was adjusted to the appropriate tension by the pre-tension system, the filament needle was slowly moved in the 1-meter length of the filament, and each time a network knot was encountered, the filament needle stopped moving, and the number of network knots was calculated, that is, the measured network degree.

[0055] (9) CV value of unevenness: The sample was tested by USTER 5 evenness instrument according to the standard of GB / T 14346-2015 "Chemical fiber filament unevenness test method capacitance method", and the specific process was as follows: the sample was placed in an environment with a temperature of 20°C and a humidity of 65% for 2h, and then the sample was passed through the capacitor electrode plate at a constant speed, and the mass in each interval was converted into an electrical signal, and the percentage of the standard deviation of all test electrical signals to the average value was the CV value of unevenness; wherein, the test speed was 200m / min, and the test time of the sample was 2.5min.

[0056] Example 1

[0057] A preparation method of cloud silk for air-permeable fabric, which employs devices as shown in Figure 1 、 Figure 2 、 Figure 3 b、 Figure 4 , the tow 13 sequentially passes through a first oiling device 1, a bottom region of a recess-shaped guide hook 16 located above, a central position of a pre-networker 2, a bottom region of a recess-shaped guide hook 17 located below, a first guide roller 3, a first hot roller 4, a second hot roller 5, a third hot roller 6, a fourth hot roller 7, a second oiling device 8, a second guide roller 9, a main networker 10, a third guide roller 11 and a winding device 12;

[0058] The tow 13 contains 0.22wt% of a matting agent, the matting agent being titanium dioxide with an average particle size of 0.35μm, and the specification of the tow 13 is 50dtex / 24f;

[0059] The first oiling device 1 is an oil nozzle, and the first oiling device 1 employs crude oil for oiling, with an oiling rate of 0.4%;

[0060] The air pressure of the pre-networker 2 is 0.40MPa;

[0061] The pre-networker 2 is an equal-section vertical plate, which is provided with a horizontal air flow jet hole, and a certain cross section of the pre-networker 2 passes through the air flow jet hole, the cross section being an Archimedes spiral, the polar angle of the Archimedes spiral being 360°, the air flow jet hole being located at a position with a polar angle of 180° on the Archimedes spiral, and the air flow jet hole facing the center of the Archimedes spiral;

[0062] The guide hooks at the inlet and outlet of the pre-networker 2 are recess-shaped guide hooks; as shown in Figure 4 , the recess-shaped guide hook is composed of a U-shaped guide hook 14 and a limiting block 15, the U-shaped guide hook 14 being horizontally arranged, and the limiting block 15 being connected with the inner wall of the U-shaped guide hook 14 for limiting the tow 13 in the bottom region of the U-shaped guide hook 14;

[0063] The Archimedes helix coefficient of the Archimedes spiral is 1mm / °, and the polar radius at a polar angle of 0° is 1.5mm; the air flow jet hole is a circular hole with a diameter of 1.1mm, and is located at the middle position of the pre-networker 2 in the vertical direction; and the length of the pre-networker 2 in the vertical direction is 25mm;

[0064] The distance between each recess-shaped guide hook and the pre-networker 2 in the vertical direction is 15mm; the included angle α of the tow 13 with the vertical direction at the recess-shaped guide hook 16 located above is 8°; and the included angle β of the tow 13 with the vertical direction at the recess-shaped guide hook 17 located below is 8°; as shown in Figure 1 ;

[0065] The air flow injection hole of the pre-networker 2 of each spinning position is communicated with a branch pipe, all the branch pipes are communicated with the same main pipe, and an automatic pressure regulating valve is arranged on the air inlet end of the main pipe;

[0066] The surface roughness of the first guide roller 3 is uniform, and the value range is 1.3 μm;

[0067] The surface of the first heat roller 4 is divided into two parts which are symmetrically distributed along the central axis of the first heat roller 4, one part has a roughness of 0.1 μm, and the other part has a roughness of 1.3 μm;

[0068] The surface of the second heat roller 5 is divided into two parts which are symmetrically distributed along the central axis of the second heat roller 5, one part has a roughness of 0.1 μm, and the other part has a roughness of 1.3 μm;

[0069] The surface roughness of the third heat roller 6 is uniform, and the value range is 0.30 μm;

[0070] The surface roughness of the fourth heat roller 7 is uniform, and the value range is 0.30 μm;

[0071] The winding number of the tow 13 on the first heat roller 4 to the fourth heat roller 7 is 0.5 turns;

[0072] The second oiling device 8 adopts oiling with an oil agent with a concentration of 20 wt%, and the oiling rate is 0.6%;

[0073] The surface roughness of the second guide roller 9 and the third guide roller 11 is uniform, and the value range is 1.3 μm;

[0074] The first guide roller 3, the first heat roller 4, the second heat roller 5, the third heat roller 6, the fourth heat roller 7, the second guide roller 9 and the third guide roller 11 all have a cylindrical structure, the diameters of the first to third guide rollers are all 110 mm, and the diameters of the first to fourth heat rollers are all 220 mm;

[0075] The linear speed of the first guide roller 3 is 1580 m / min, the temperature of the first heat roller 4 is 52℃, the linear speed of the first heat roller 4 is 1590 m / min, the temperature of the second heat roller 5 is 52℃, the linear speed of the second heat roller 5 is 1690 m / min, the temperature of the third heat roller 6 is 102℃, the linear speed of the third heat roller 6 is 3100 m / min, the temperature of the fourth heat roller 7 is 102℃, the linear speed of the fourth heat roller 7 is 3100 m / min, the linear speed of the second guide roller 9 is 3110 m / min, the air pressure of the main networker 10 is 0.38 MPa, the linear speed of the third guide roller 11 is 3125 m / min, and the winding speed of the winding device 12 is 3175 m / min.

[0076] The final breathable fabric yarn made of cloud hemp has a CV value of 14.5% for unevenness, a kink density of 28 / m, an elongation at break of 85.7%, a breaking strength of 3.45 cN / dtex, a boiling water shrinkage of 34.1%, a maximum kink length before boiling water shrinkage test of 0.51 cm, a maximum kink length after boiling water shrinkage test of 0.34 cm, a downgrading rate of 0.05%, a number of breakages of 5.3 times / 18 positions·24 hours, and a deviation of network degree of 3 / m (a standard value of network degree is 23 / m).

[0077] Comparative Example 1

[0078] A method for preparing a breathable fabric yarn made of cloud hemp, which is different from Example 1 only in that the roughness of the surface of the first guide roller is uniform, and the roughness value is 1.0 μm.

[0079] The final breathable fabric yarn made of cloud hemp has a CV value of 10.9% for unevenness, a kink density of 21 / m, an elongation at break of 85.7%, a breaking strength of 3.46 cN / dtex, a boiling water shrinkage of 34.1%, a maximum kink length before boiling water shrinkage test of 0.42 cm, a maximum kink length after boiling water shrinkage test of 0.28 cm, a downgrading rate of 0.05%, a number of breakages of 5.3 times / 18 positions·24 hours, and a deviation of network degree of 3 / m (a standard value of network degree is 23 / m).

[0080] Compared with Example 1, the elongation at break, the breaking strength, the boiling water shrinkage, the downgrading rate, the number of breakages, and the deviation of network degree of Comparative Example 1 do not change obviously, the CV value of unevenness decreases by 24.8%, the kink density decreases by 25%, the maximum kink length before boiling water shrinkage test decreases by 17.6%, and the maximum kink length after boiling water shrinkage test decreases by 17.6%, because the roughness is represented by the difference between the peak top and the valley of the protrusion of the solid surface, the smaller the roughness, the smaller the difference between the peak top and the valley of the protrusion, the larger the contact surface between the yarn and the solid surface, and the better the holding force of the yarn on the solid surface; the roughness value of the surface of the first guide roller is 1.0 μm, which is relatively small, the holding force of the yarn on the first guide roller is better, the yarn is not easy to slip, the kink density decreases, the CV value of unevenness decreases, and because the holding force of the yarn on the first guide roller is better, the yarn shakes less after entering the hot roller from the first guide roller, the yarn is heated more uniformly on the hot roller, and part of the network points are easily heated and penetrated, so the maximum kink length before and after the boiling water shrinkage test decreases.

[0081] Comparative Example 2

[0082] A preparation method of the breathable fabric cloud hemp silk, the only difference from example 1 is that the roughness of the first guide roller is uniform, and the roughness value is 1.8 μm.

[0083] The final breathable fabric cloud hemp silk has a CV value of 15.4% for the unevenness of the strip, a kink density of 30 / m, an elongation at break of 85.1%, a breaking strength of 3.45 cN / dtex, a boiling water shrinkage of 34.2%, a maximum kink length before the boiling water shrinkage test of 0.56 cm, a maximum kink length after the boiling water shrinkage test of 0.37 cm, a downgraded hair rate of 0.09%, a number of broken ends of 7.6 times / 18 positions·24 hours, and a network deviation of 3 / m (the standard value of the network is 23 / m).

[0084] Compared with example 1, the changes of the elongation at break, the breaking strength, the boiling water shrinkage and the network deviation of comparative example 2 are not obvious, the maximum kink length before the boiling water shrinkage test increases by 9.8%, the maximum kink length after the boiling water shrinkage test increases by 8.8%, the downgraded hair rate increases by 80%, and the number of broken ends increases by 43.4%, because the roughness value of the first guide roller is 1.8 μm, the roughness is large, the holding force of the yarn on the first guide roller is poor, the yarn cannot form draft on the first guide roller, and even the problem of winding around the roller cannot be produced, so the number of broken ends increases; at the same time, because the roughness of the first guide roller is large, the yarn shakes greatly after entering the hot roller from the first guide roller, the contact area of the yarn on the hot roller is small, and the heating efficiency on the hot roller is poor, so cold stretching is prone to occur, and the number of hairs increases; because the contact area of the yarn on the hot roller is small, the network points cannot be completely heated, so the maximum kink length before and after the boiling water shrinkage test increases.

[0085] Comparative example 3

[0086] A preparation method of the breathable fabric cloud hemp silk, the only difference from example 1 is that the roughness of the first guide roller is uniform, and the roughness value is 1.8 μm.

[0087] The final breathable fabric cloud hemp silk has a CV value of 15.4% for the unevenness of the strip, a kink density of 30 / m, an elongation at break of 85.1%, a breaking strength of 3.45 cN / dtex, a boiling water shrinkage of 34.2%, a maximum kink length before the boiling water shrinkage test of 0.56 cm, a maximum kink length after the boiling water shrinkage test of 0.37 cm, a downgraded hair rate of 0.09%, a number of broken ends of 7.6 times / 18 positions·24 hours, and a network deviation of 3 / m (the standard value of the network is 23 / m).

[0088] Compared with Example 1, the boiling water shrinkage, downgrading rate of noil, number of breakage, change of network deviation of Comparative Example 3 is not obvious, the CV value of unevenness of yarn is reduced by 27.6%, the slub density is reduced by 28.6%, the maximum slub length before boiling water shrinkage test is reduced by 21.6%, the maximum slub length after boiling water shrinkage test is reduced by 23.5%, the elongation at break is reduced by 2%, the breaking strength is increased by 1.7%, because: the roughness of the circumferential surface of the first heat roller and the second heat roller is uniform, the roughness is 0.1 μm, and the roughness is small, so that the holding force of the tow on the first heat roller and the second heat roller is better, and it is not easy to slip, so the slub density and the CV value of unevenness of yarn are reduced; at the same time, due to the small roughness, the contact area of the tow on the first heat roller and the second heat roller is larger, and the heating efficiency on the first heat roller and the second heat roller is higher, so that the heating of the tow on the first heat roller is more uniform, and part of the network points are heated through, so the maximum slub length is smaller; in addition, due to the better holding force of the tow on the first heat roller and the second heat roller, the effective draft ratio formed between the third heat roller and the second heat roller is higher, and the molecular orientation degree is higher, so the breaking strength is increased and the elongation at break is reduced.

[0089] Comparative Example 4

[0090] A preparation method of cloud hemp yarn for breathable fabric, which is different from Example 1 only in that the roughness of the circumferential surface of the first heat roller is uniform, and the value is 1.3 μm, and the roughness of the circumferential surface of the second heat roller is uniform, and the value is 1.3 μm.

[0091] The CV value of unevenness of yarn of the finally prepared cloud hemp yarn for breathable fabric is 14.7%, the slub density is 29 / m, the elongation at break is 84.9%, the breaking strength is 3.42 cN / dtex, the boiling water shrinkage is 34.2%, the maximum slub length before boiling water shrinkage test is 0.62 cm, the maximum slub length after boiling water shrinkage test is 0.41 cm, the downgrading rate of noil is 0.10%, the number of breakage is 8.4 times / 18 positions·24 hours, and the network deviation is 3 / m (the network standard value is 23 / m).

[0092] Compared with Example 1, the changes of the CV value of the evenness, the kink density, the elongation at break, the breaking strength, the boiling water shrinkage and the deviation of the network degree of Comparative Example 4 are not obvious, the maximum kink length before the boiling water shrinkage test increases by 21.6%, the maximum kink length after the boiling water shrinkage test increases by 20.6%, the downgrading rate of the hairiness increases by 100%, and the number of the broken ends increases by 58.5%, because: the roughness of the circumferential surface of the first and second heat rollers is uniform and consistent, and the roughness is 1.3 μm, and the roughness is large, which leads to small holding force of the filament on the first and second heat rollers, and the problem of unable to draft easily occurs, so the number of the broken ends increases; at the same time, because the roughness of the circumferential surface of the first and second heat rollers is large, the contact area of the filament on the first and second heat rollers is small, and the heating efficiency on the first and second heat rollers is poor, so the cold stretching easily occurs, and the number of the hairiness increases; because the contact area of the filament on the first and second heat rollers is small, the network points cannot be completely heated, so the maximum kink length before and after the boiling water shrinkage test increases.

[0093] Example 2

[0094] A preparation method of the cloud hemp filament for the air-permeable fabric, the device used is shown in Figure 1 、 Figure 2 、 Figure 3 b、 Figure 4 , the filament 13 passes through the first oiling device 1, the bottom region of the groove-shaped guide hook 16 located above, the central position of the pre-networker 2, the bottom region of the groove-shaped guide hook 17 located below, the first guide roller 3, the first heat roller 4, the second heat roller 5, the third heat roller 6, the fourth heat roller 7, the second oiling device 8, the second guide roller 9, the main networker 10, the third guide roller 11 and the winding device 12 in sequence;

[0095] The filament 13 contains 0.21 wt% of the matting agent, the matting agent is titanium dioxide with an average particle size of 0.35 μm, and the specification of the filament 13 is 55 dtex / 24 f;

[0096] The first oiling device 1 is an oil nozzle; the first oiling device 1 uses the original oiling, and the oiling rate is 0.45%;

[0097] The air pressure of the pre-networker 2 is 0.38 MPa;

[0098] The pre-networker 2 is an equal-section vertical plate, and the air flow injection hole arranged horizontally is arranged on the pre-networker 2, a certain cross section of the pre-networker 2 passes through the air flow injection hole, the cross section is an Archimedes spiral, the polar angle of the Archimedes spiral is 400°, the air flow injection hole is located at the position with the polar angle of 180° on the Archimedes spiral, and the air flow injection hole faces the center of the Archimedes spiral;

[0099] The guide wire hooks at the inlet and outlet of the pre-networker 2 are groove-shaped guide wire hooks; as shown in Figure 4 The groove-shaped guide wire hook is composed of a U-shaped guide wire hook 14 and a limiting block 15, as shown in Figure 4 The U-shaped guide wire hook 14 is horizontally arranged, and the limiting block 15 is connected with the inner wall of the U-shaped guide wire hook 14, for limiting the fiber bundle 13 in the bottom area of the U-shaped guide wire hook 14;

[0100] The Archimedes helix coefficient of the Archimedes spiral is 1.6 mm / °, and the polar radius when the polar angle is 0° is 1.7 mm; the air flow injection hole is a circular hole with a diameter of 1.2 mm, which is located in the middle position of the pre-networker 2 along the vertical direction; the length of the pre-networker 2 along the vertical direction is 23 mm;

[0101] The distance between each groove-shaped guide wire hook and the pre-networker 2 along the vertical direction is 13 mm; the included angle α between the fiber bundle 13 at the upper groove-shaped guide wire hook 16 and the vertical direction is 6°; the included angle β between the fiber bundle 13 at the lower groove-shaped guide wire hook 17 and the vertical direction is 6°; as shown in Figure 1

[0102] The air flow injection hole of each pre-networker 2 of each spinning position is communicated with a branch pipe, and all the branch pipes are communicated with the same main pipe, and an automatic pressure regulating valve is arranged on the air inlet end of the main pipe;

[0103] The surface roughness of the first guide wire roller 3 is uniform, and the value range is 1.4 μm;

[0104] The surface of the first heat roller 4 is divided into two parts which are symmetrically distributed along the central axis of the first heat roller 4, one part has a roughness of 0.14 μm, and the other part has a roughness of 1.4 μm;

[0105] The surface of the second heat roller 5 is divided into two parts which are symmetrically distributed along the central axis of the second heat roller 5, one part has a roughness of 0.14 μm, and the other part has a roughness of 1.4 μm;

[0106] The surface roughness of the third heat roller 6 is uniform, and the value range is 0.33 μm;

[0107] The surface roughness of the fourth heat roller 7 is uniform, and the value range is 0.33 μm;

[0108] The winding number of the fiber bundle 13 on the first heat roller 4 to the fourth heat roller 7 is 0.5 turns;

[0109] The second oiling device 8 uses oiling with an oil agent with a concentration of 19.5 wt%, and the oiling rate is 0.55%;

[0110] The surface roughness of the second guide wire roller 9 and the third guide wire roller 11 is uniform, and the value range is 1.4 μm;​

[0111] The first guide roller 3, the first hot roller 4, the second hot roller 5, the third hot roller 6, the fourth hot roller 7, the second guide roller 9, and the third guide roller 11 are all cylindrical structures. The diameter of the first to third guide rollers is 110 mm, and the diameter of the first to fourth hot rollers is 220 mm.

[0112] The linear speed of the first guide roller 3 is 1590 m / min, the temperature of the first hot roller 4 is 50℃, and the linear speed of the first hot roller 4 is 1600 m / min. The temperature of the second hot roller 5 is 50℃, and the linear speed of the second hot roller 5 is 1700 m / min. The temperature of the third hot roller 6 is 100℃, and the linear speed of the third hot roller 6 is 3130 m / min. The temperature of the fourth hot roller 7 is 100℃, and the linear speed of the fourth hot roller 7 is 3130 m / min. The linear speed of the second guide roller 9 is 3140 m / min. The air pressure of the main network device 10 is 0.4 MPa. The linear speed of the third guide roller 11 is 3155 m / min. The winding speed of the winding device 12 is 3205 m / min.

[0113] The final breathable fabric made from cloud hemp fibers had a yarn unevenness CV value of 14.1%, a slub density of 26 nodes / meter, a breaking elongation of 85.3%, a breaking strength of 3.47 cN / dtex, a boiling water shrinkage rate of 36.5%, a maximum slub length of 0.61 cm before the boiling water shrinkage test, a maximum slub length of 0.39 cm after the boiling water shrinkage test, a fiber degradation rate of 0.04%, a breakage count of 4.7 times / 18 positions·24 hours, and a network density deviation of 2 nodes / meter (the standard network density value is 22 nodes / meter).

[0114] Example 3

[0115] A method for preparing breathable fabric using cloud hemp yarn, employing an apparatus such as... Figure 1 , Figure 2 , Figure 3 b, Figure 4 As shown, the filament bundle 13 passes sequentially through the first oiling device 1, the bottom area of ​​the upper grooved guide hook 16, the center position of the pre-networker 2, the bottom area of ​​the lower grooved guide hook 17, the first guide roller 3, the first hot roller 4, the second hot roller 5, the third hot roller 6, the fourth hot roller 7, the second oiling device 8, the second guide roller 9, the main networker 10, the third guide roller 11, and the winding device 12;

[0116] The tow 13 contains 0.23 wt% of a matting agent, which is titanium dioxide with an average particle size of 0.35 μm. The specification of the tow 13 is 56 dtex / 24f.

[0117] The first oiling device 1 is an oil nozzle; the first oiling device 1 uses crude oil for oiling, and the oiling rate is 0.45%;

[0118] The air pressure of the pre-networker 2 is 0.42 MPa;

[0119] The pre-networker 2 is an equal-section vertical plate, which is provided with an air flow jet hole arranged horizontally, and a certain cross section of the pre-networker 2 passes through the air flow jet hole, the cross section is an Archimedes spiral, the polar angle of the Archimedes spiral is 420°, the air flow jet hole is located at a position with a polar angle of 180° on the Archimedes spiral, and the air flow jet hole faces the center of the Archimedes spiral;

[0120] The guide wire hook at the inlet and outlet of the pre-networker 2 is a groove-shaped guide wire hook; as shown in Figure 4 , the groove-shaped guide wire hook is composed of a U-shaped guide wire hook 14 and a limiting block 15, the U-shaped guide wire hook 14 is arranged horizontally, the limiting block 15 is connected with the inner wall of the U-shaped guide wire hook 14, and is used for limiting the fiber bundle 13 in the bottom area of the U-shaped guide wire hook 14;

[0121] The Archimedes helix coefficient of the Archimedes spiral is 1.8 mm / °, and the polar radius when the polar angle is 0° is 1.8 mm; the air flow jet hole is a circular hole with a diameter of 1.2 mm, and is located at the middle position of the pre-networker 2 in the vertical direction; in the vertical direction, the length of the pre-networker 2 is 26 mm;

[0122] In the vertical direction, the distance between each groove-shaped guide wire hook and the pre-networker 2 is 15 mm; the included angle α between the fiber bundle 13 and the vertical direction at the upper groove-shaped guide wire hook 16 is 5°; the included angle β between the fiber bundle 13 and the vertical direction at the lower groove-shaped guide wire hook 17 is 5°; the included angle α and the included angle β are shown in Figure 1 ;

[0123] The air flow jet hole of each pre-networker 2 of each spinning position is communicated with a branch pipe, all the branch pipes are communicated with the same main pipe, and an automatic pressure regulating valve is arranged on the air inlet end of the main pipe;

[0124] The surface roughness of the first guide wire roller 3 is uniform, and the value range is 1.5 μm;

[0125] The surface of the first heat roller 4 is divided into two parts which are symmetrically distributed along the central axis of the first heat roller 4, one part has a roughness of 0.15 μm, and the other part has a roughness of 1.5 μm;

[0126] The surface of the second heat roller 5 is divided into two parts which are symmetrically distributed along the central axis of the second heat roller 5, one part has a roughness of 0.15 μm, and the other part has a roughness of 1.5 μm;

[0127] The surface roughness of the third heat roller 6 is uniform, and the value range is 0.35 μm;

[0128] The fourth thermal roller 7 has a uniform roughness of the peripheral surface, and the value range is 0.35 μm;

[0129] The winding number of the filament 13 on the first thermal roller 4 to the fourth thermal roller 7 is 0.5 turns;

[0130] The second oiling device 8 uses oiling with an oil agent having a concentration of 20.5 wt%, and the oiling rate is 0.5%;

[0131] The second godet roller 9 and the third godet roller 11 have a uniform roughness of the peripheral surface, and the value range is 1.5 μm;

[0132] The first godet roller 3, the first thermal roller 4, the second thermal roller 5, the third thermal roller 6, the fourth thermal roller 7, the second godet roller 9 and the third godet roller 11 all have a cylindrical structure, the diameter of the first to third godet rollers is 110 mm, and the diameter of the first to fourth thermal rollers is 220 mm;

[0133] The linear speed of the first godet roller 3 is 1590 m / min, the temperature of the first thermal roller 4 is 55℃, the linear speed of the first thermal roller 4 is 1600 m / min, the temperature of the second thermal roller 5 is 55℃, the linear speed of the second thermal roller 5 is 1700 m / min, the temperature of the third thermal roller 6 is 105℃, the linear speed of the third thermal roller 6 is 3150 m / min, the temperature of the fourth thermal roller 7 is 105℃, the linear speed of the fourth thermal roller 7 is 3150 m / min, the linear speed of the second godet roller 9 is 3160 m / min, the air pressure of the main networker 10 is 0.42 MPa, the linear speed of the third godet roller 11 is 3175 m / min, and the winding speed of the winding device 12 is 3225 m / min.

[0134] The strip unevenness CV value of the finally prepared breathable fabric bamboo filament is 14.4%, the kink density is 27 / m, the elongation at break is 85.4%, the breaking strength is 3.5 cN / dtex, the boiling water shrinkage is 35.1%, the maximum kink length before the boiling water shrinkage test is 0.43 cm, the maximum kink length after the boiling water shrinkage test is 0.28 cm, the downgrading rate of hair is 0.04%, the number of broken ends is 3.6 times / 18 positions·24 hours, and the network deviation is 3 / m (the network standard value is 22 / m).

[0135] Example 4

[0136] A preparation method of a breathable fabric bamboo filament, the device used is as shown in Figure 1 、 Figure 2 、 Figure 3 b of, Figure 4As shown, the tow 13 passes through the first oiling device 1, the bottom region of the recessed guide hook 16 located above, the central position of the pre-networker 2, the bottom region of the recessed guide hook 17 located below, the first guide roller 3, the first hot roller 4, the second hot roller 5, the third hot roller 6, the fourth hot roller 7, the second oiling device 8, the second guide roller 9, the main networker 10, the third guide roller 11 and the winding device 12 in turn;

[0137] The tow 13 contains 0.24wt% of matting agent, which is titanium dioxide with an average particle size of 0.35μm, and the specification of the tow 13 is 61dtex / 24f.

[0138] The first oiling device 1 is an oil nozzle; the first oiling device 1 uses crude oil for oiling, and the oiling rate is 0.5%; the air pressure of the pre-networker 2 is 0.45MPa;

[0139] The pre-networker 2 is an equal-section vertical plate, which is provided with a horizontal air flow jet hole; a certain cross section of the pre-networker 2 passes through the air flow jet hole, the cross section is an Archimedes spiral, the polar angle of the Archimedes spiral is 450°, the air flow jet hole is located at a position with a polar angle of 180° on the Archimedes spiral, and the air flow jet hole faces the center of the Archimedes spiral;

[0140] The guide hooks at the inlet and outlet of the pre-networker 2 are recessed guide hooks; as shown, Figure 4 The recessed guide hook is composed of a U-shaped guide hook 14 and a limiting block 15, the U-shaped guide hook 14 is horizontally arranged, the limiting block 15 is connected with the inner wall of the U-shaped guide hook 14, and is used for limiting the tow 13 in the bottom region of the U-shaped guide hook 14;

[0141] The Archimedes helix coefficient of the Archimedes spiral is 2mm / °, and the polar radius at a polar angle of 0° is 2mm; the air flow jet hole is a circular hole with a diameter of 1.3mm, and is located at the middle position of the pre-networker 2 in the vertical direction; in the vertical direction, the length of the pre-networker 2 is 27mm;

[0142] In the vertical direction, the distance between each recessed guide hook and the pre-networker 2 is 17mm; the angle α between the tow 13 at the recessed guide hook 16 located above and the vertical direction is 10°; the angle β between the tow 13 at the recessed guide hook 17 located below and the vertical direction is 10°; the angle α and the angle β are shown in Figure 1 ;

[0143] The air flow jet hole of each pre-networker 2 at each spinning position is communicated with a branch pipe, all the branch pipes are communicated with a same main pipe, and an automatic pressure regulating valve is arranged on the air inlet end of the main pipe;

[0144] The surface roughness of the first guide roller 3 is uniform, and the value range is 1.4μm;

[0145] The peripheral surface of the first heating roller 4 is divided into two parts symmetrically distributed along the central axis of the first heating roller 4, one part having a roughness of 0.13 μm and the other part having a roughness of 1.4 μm;

[0146] The peripheral surface of the second heating roller 5 is divided into two parts symmetrically distributed along the central axis of the second heating roller 5, one part having a roughness of 0.13 μm and the other part having a roughness of 1.4 μm;

[0147] The peripheral surface of the third heating roller 6 has a uniform roughness, with a value ranging from 0.32 μm;

[0148] The peripheral surface of the fourth heating roller 7 has a uniform roughness, with a value ranging from 0.32 μm;

[0149] The number of winding turns of the filament 13 on the first heating roller 4 to the fourth heating roller 7 is 0.5 turns;

[0150] The second oiling device 8 uses oiling with an oil agent having a concentration of 20 wt%, with an oiling rate of 0.53%;

[0151] The peripheral surface of the second guide roller 9 and the third guide roller 11 has a uniform roughness, with a value ranging from 1.4 μm;

[0152] The first guide roller 3, the first heating roller 4, the second heating roller 5, the third heating roller 6, the fourth heating roller 7, the second guide roller 9 and the third guide roller 11 all have a cylindrical structure, the diameters of the first to third guide rollers are all 110 mm, and the diameters of the first to fourth heating rollers are all 220 mm;

[0153] The linear speed of the first guide roller 3 is 1600 m / min, the temperature of the first heating roller 4 is 60 °C, the linear speed of the first heating roller 4 is 1610 m / min, the temperature of the second heating roller 5 is 60 °C, the linear speed of the second heating roller 5 is 1710 m / min, the temperature of the third heating roller 6 is 110 °C, the linear speed of the third heating roller 6 is 3200 m / min, the temperature of the fourth heating roller 7 is 110 °C, the linear speed of the fourth heating roller 7 is 3200 m / min, the linear speed of the second guide roller 9 is 3210 m / min, the air pressure of the main networker 10 is 0.4 MPa, the linear speed of the third guide roller 11 is 3225 m / min, and the winding speed of the winding device 12 is 3275 m / min.

[0154] The final breathable fabric yarn made of cloud hemp has a CV value of 15.6% for unevenness, a kink density of 30 / m, an elongation at break of 84.8%, a breaking strength of 3.61 cN / dtex, a boiling water shrinkage of 34.7%, a maximum kink length before the boiling water shrinkage test of 0.71 cm, a maximum kink length after the boiling water shrinkage test of 0.46 cm, a downgraded hairiness rate of 0.05%, a number of broken ends of 4.1 times / 18 positions·24 hours, and a deviation of network degree of 3 / m (a standard value of network degree is 23 / m).

[0155] Example 5

[0156] A method for preparing a breathable fabric yarn made of cloud hemp, which is different from that of Example 1 only in that the polar angle of the Archimedes spiral is 350°.

[0157] The final breathable fabric yarn made of cloud hemp of Example 5 has a CV value of 13.7% for unevenness, a kink density of 25 / m, an elongation at break of 85.6%, a breaking strength of 3.47 cN / dtex, a boiling water shrinkage of 33.9%, a maximum kink length before the boiling water shrinkage test of 0.50 cm, a maximum kink length after the boiling water shrinkage test of 0.33 cm, a downgraded hairiness rate of 0.06%, a number of broken ends of 6.3 times / 18 positions·24 hours, and a deviation of network degree of 3 / m (a standard value of network degree is 23 / m).

[0158] Compared with Example 1, the CV value for unevenness and the kink density of the breathable fabric yarn made of cloud hemp of Example 5 are reduced, the downgraded hairiness rate and the number of broken ends are increased, and the remaining performance indicators do not change significantly. This is because when the polar angle of the Archimedes spiral is 350°, the network air pressure is discharged from the pre-networking device earlier, resulting in a decrease in network degree, which in turn affects the kink density and the CV value for unevenness. In addition, due to the early discharge of the network air pressure, the air pressure in the inner chamber of the pre-networking device is unstable, the tows are prone to rub against the edges of the pre-networking device, resulting in an increase in the downgraded hairiness rate and the number of broken ends.

[0159] Example 6

[0160] A method for preparing a breathable fabric yarn made of cloud hemp, which is different from that of Example 4 only in that the polar angle of the Archimedes spiral is 460°.

[0161] The final prepared breathable fabric yarn of example 6 has a CV value of 15.3% for the unevenness of the yarn, a kink density of 29 / m, an elongation at break of 84.6%, a breaking strength of 3.60 cN / dtex, a boiling water shrinkage of 34.9%, a maximum kink length before the boiling water shrinkage test of 0.72 cm, a maximum kink length after the boiling water shrinkage test of 0.47 cm, a downgraded hairiness rate of 0.07%, a number of breakages of 5.9 times per 18 positions per 24 hours, and a deviation of the network degree of 3 / m (the standard value of the network degree is 23 / m).

[0162] Compared with example 4, the prepared breathable fabric yarn of example 6 has an increased downgraded hairiness rate and a number of breakages, and the remaining performance indicators do not change significantly. This is because when the polar angle of the Archimedes spiral is 460°, the large network air pressure cannot be discharged from the pre-networker in time, the airflow in the pre-networker is turbulent, and the downgraded hairiness rate and the number of breakages are increased.

[0163] Example 7

[0164] A method for preparing a breathable fabric yarn of example 7 is different from example 1 only in that the airflow injection hole is located at a position with a polar angle of 170° on the Archimedes spiral in the pre-networker.

[0165] The final prepared breathable fabric yarn of example 7 has a CV value of 13.5% for the unevenness of the yarn, a kink density of 25 / m, an elongation at break of 85.9%, a breaking strength of 3.44 cN / dtex, a boiling water shrinkage of 33.8%, a maximum kink length before the boiling water shrinkage test of 0.49 cm, a maximum kink length after the boiling water shrinkage test of 0.32 cm, a downgraded hairiness rate of 0.07%, a number of breakages of 6.0 times per 18 positions per 24 hours, and a deviation of the network degree of 3 / m (the standard value of the network degree is 23 / m).

[0166] Compared with example 1, the prepared breathable fabric yarn of example 7 has a reduced CV value for the unevenness of the yarn and a kink density, an increased downgraded hairiness rate and a number of breakages, and the remaining performance indicators do not change significantly. This is because when the airflow injection hole is located at a position with a polar angle of 170° on the Archimedes spiral, the airflow in the pre-networker is directly introduced into another spiral after being blown to the yarn bundle, thereby causing the air pressure in the inner chamber of the pre-networker to be unstable, reducing the kink density and the CV value for the unevenness of the yarn, and causing the yarn bundle to easily rub against the edge of the pre-networker, thereby increasing the downgraded hairiness rate and the number of breakages.

[0167] Example 8

[0168] A method for preparing a breathable fabric yarn of example 8 is different from example 1 only in that the guide hooks at the inlet and outlet of the pre-networker are U-shaped guide hooks, and no limiting block is arranged.

[0169] The final breathable fabric yarn made of cloud hemp of Example 8 has a CV value of 14.1% for the unevenness of the evenness, a kink density of 27 / m, an elongation at break of 85.9%, a breaking strength of 3.44 cN / dtex, a boiling water shrinkage of 34.2%, a maximum kink length before the boiling water shrinkage test of 0.49 cm, a maximum kink length after the boiling water shrinkage test of 0.32 cm, a downgraded hairiness rate of 0.08%, a number of breakages of 7.0 times / 18 positions·24 hours, and a network deviation of 4 / m (a standard value of network is 23 / m).

[0170] Compared with Example 1, the downgraded hairiness rate, the number of breakages, and the network deviation of the breathable fabric yarn made of cloud hemp of Example 8 are all increased, and the remaining performance indicators do not change significantly. This is because the angle of the yarn before and after the pre-networking device is large, and the use of the U-shaped guide hook causes the yarn to not be locked in the middle position of the pre-networking device under a large pre-networking air pressure, thereby causing inconsistent stress points and uneven network points, and the network deviation is increased. At the same time, the inconsistent stress points also cause the yarn to be more likely to rub against the edge of the pre-networking device, thereby increasing the hairiness and the number of breakages.

[0171] Example 9

[0172] A method for preparing a breathable fabric yarn made of cloud hemp, which is different from Example 1 only in that the pre-networking device is replaced by the pre-networking device in the patent application with the publication number CN109594137A (the cross section is shown in FIG. a). Figure 3

[0173] The final breathable fabric yarn made of cloud hemp of Example 9 has a CV value of 14.4% for the unevenness of the evenness, a kink density of 28 / m, an elongation at break of 85.4%, a breaking strength of 3.44 cN / dtex, a boiling water shrinkage of 33.9%, a maximum kink length before the boiling water shrinkage test of 0.50 cm, a maximum kink length after the boiling water shrinkage test of 0.33 cm, a downgraded hairiness rate of 0.07%, a number of breakages of 6.9 times / 18 positions·24 hours, and a network deviation of 4 / m (a standard value of network is 23 / m).

[0174] Compared with Example 1, the downgraded hairiness rate, the number of breakages, and the network deviation of the breathable fabric yarn made of cloud hemp of Example 9 are all increased, and the remaining performance indicators do not change significantly. This is because the pre-networking air pressure is high, and the yarn swings greatly in the pre-networking device, causing the yarn to be subjected to inconsistent impact forces of the vertical jet flow in the pre-networking device, thereby causing uneven network points and a large network deviation. At the same time, the spiral airflow in the pre-networking device cannot be discharged, causing the yarn to rub against the pre-networking device, thereby increasing the hairiness and the number of breakages.​

Claims

1. A process for the preparation of cloud silk for air permeable fabric, characterized by, The tow passes through a first oiling device, a pre-networking device, a first guide roller, a first heating roller, a second heating roller, a third heating roller, a fourth heating roller, a second oiling device, a second guide roller, a main networking device, a third guide roller and a winding device in sequence. The surface roughness of the first guide roller is uniform and ranges from 1.3 to 1.5 μm. The surface of the first heating roller is divided into two parts which are symmetrically distributed along the central axis of the first heating roller, one part has a roughness of 0.1-0.15 μm, and the other part has a roughness of 1.3-1.5 μm. The surface of the second heating roller is divided into two parts which are symmetrically distributed along the central axis of the second heating roller, one part has a roughness of 0.1-0.15 μm, and the other part has a roughness of 1.3-1.5 μm. The surface roughness of the third heating roller is uniform and ranges from 0.30 to 0.35 μm. The surface roughness of the fourth heating roller is uniform and ranges from 0.30 to 0.35 μm. The winding turns of the tow on the first heating roller to the fourth heating roller are all 0.5 turns.

2. A process for the preparation of cloud silk yarn for use in air permeable fabric as claimed in claim 1, wherein, The first oiling device is an oil nozzle. The air pressure of the pre-networking device is 0.38-0.45 MPa. The pre-networking device is an equal-section vertical plate, which is provided with a horizontal air flow jet hole. A certain cross section of the pre-networking device passes through the air flow jet hole, the cross section is an Archimedes spiral, the polar angle of the Archimedes spiral is greater than or equal to 360° and less than or equal to 450°, the air flow jet hole is located at a position of the Archimedes spiral with a polar angle of 180°, and the air flow jet hole faces the center of the Archimedes spiral. The guide hooks at the inlet and outlet of the pre-networking device are groove-shaped guide hooks, which are composed of a U-shaped guide hook and a limiting block. The U-shaped guide hook is horizontally arranged, and the limiting block is connected with the inner wall of the U-shaped guide hook to limit the tow in the bottom region of the U-shaped guide hook. The tow passes through the bottom region of the upper groove-shaped guide hook, the central position of the pre-networking device and the bottom region of the lower groove-shaped guide hook in sequence from top to bottom.

3. A process for the preparation of cloud silk yarn for air permeable fabric as claimed in claim 2, wherein, The Archimedes helix coefficient of the Archimedes spiral is 1-2 mm / °, and the polar radius when the polar angle is 0° is 1.5-2 mm. The air flow jet hole is a circular hole with a diameter of 1.1-1.3 mm, and is located at the middle position of the pre-networking device in the vertical direction. The length of the pre-networking device in the vertical direction is 23-27 mm.

4. A process for the preparation of cloud silk from jute for use in air permeable fabric as claimed in claim 2, wherein, The distance between each groove-shaped guide hook and the pre-networking device in the vertical direction is 13-17 mm. The angle α between the tow at the upper groove-shaped guide hook and the vertical direction is 5-10°. The angle β between the tow at the lower groove-shaped guide hook and the vertical direction is 5-10°.

5. A process for the preparation of cloud silk from jute for use in air permeable fabric as claimed in claim 2, wherein, The air flow jet holes of the pre-networking devices of all the spinning positions are communicated with a branch pipe, all the branch pipes are communicated with a same main pipe, and an automatic pressure regulating valve is arranged on the air inlet end of the main pipe.

6. A process for the preparation of cloud silk from jute for use in air permeable fabric as claimed in claim 1, wherein, The linear speed of the first godet roller is 1580-1600 m / min, the temperature of the first heat roller is 50-60℃, the linear speed of the first heat roller is 1590-1610 m / min, the temperature of the second heat roller is 50-60℃, the linear speed of the second heat roller is 1690-1710 m / min, the temperature of the third heat roller is 100-110℃, the linear speed of the third heat roller is 3100-3200 m / min, the temperature of the fourth heat roller is 100-110℃, the linear speed of the fourth heat roller is 3100-3200 m / min, the linear speed of the second godet roller is 3110-3210 m / min, the linear speed of the third godet roller is 3125-3225 m / min, and the winding speed of the winding device is 3175-3275 m / min.

7. A process for the preparation of cloud silk from jute for use in air permeable fabric as claimed in claim 1, wherein, The air pressure of the main network device is 0.38-0.42 MPa; the first oiling device uses crude oil for oiling, and the oiling rate is 0.4-0.5%; the second oiling device uses oil with a concentration of 19.5-20.5 wt% for oiling, and the oiling rate is 0.5-0.6%.

8. A process for the preparation of cloud silk from jute for use in air permeable fabric as claimed in claim 1, wherein, The tow contains 0.21-0.24 wt% of a delustering agent, and the size of the tow is 50-61 dtex / 24 f.

9. A process for the preparation of cloud silk for use in a breathable fabric according to any one of claims 2 to 8, characterized in that, The CV value of the strip unevenness of the breathable fabric using the cloud hemp yarn is 13.5-15.6%, the kink density is 26-30 / m, the elongation at break is 84.8-85.7%, the breaking strength is 3.45-3.61 cN / dtex, the boiling water shrinkage is 34.1-36.5%, the maximum kink length before the boiling water shrinkage test is 0.43-0.71 cm, the maximum kink length after the boiling water shrinkage test is 0.28-0.46 cm, the downgraded hair rate is ≤0.05%, the number of broken ends is ≤5.3 times / 18 positions·24 hours, and the network deviation is ≤3 / m.

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