Nylon 66 siro-spun core-spun yarn and preparation method thereof

Abstract

The present invention relates to a nylon 66 Siro-spun core-spun yarn and a preparation method thereof. The core yarn of the nylon 66 Siro-spun core-spun yarn is a single strand or multiple strands of nylon 66, and the outer fiber is a regenerated cellulose fiber, or is composed of regenerated cellulose fiber and cotton fiber. The preparation method is as follows: the core yarn is fed into the jaws of the front roller through a guide wheel, and two parallel outer fiber rovings are simultaneously fed into a three-roller long and short apron drafting device through a collector, and are flattened in a drafting area. When the outer fiber roving passes through the front roller, the core yarn passes through a guide frame and enters between the two outer fiber rovings, and is always located in the middle. The three yarns are combined, twisted, and wound onto a spun yarn bobbin, so as to obtain the nylon 66 Siro-spun core-spun yarn. The present invention combines the excellent characteristics of nylon 66 and regenerated cellulose, not only enriches the types of core-spun yarns, but also improves the strength, yarn quality, and product grade of the core-spun yarns.

Description

Technical Field

[0001] The invention belongs to the technical field of core-spun yarns and relates to a nylon 66 siro-spun core-spun yarn and a preparation method thereof. Background Art

[0002] As people's living standards improve, their requirements for clothing are getting higher and higher, and they are more inclined to choose fabrics made of environmentally friendly materials. Regenerated cellulose fiber is chosen by more textile workers. Nylon 66 is mainly filament, which is used as the core yarn in the fabric to improve the strength and wear resistance of the fabric.

[0003] Nylon 66, commonly known as nylon 66, has high strength, good resilience, and the highest wear resistance among textile fibers. Its resistance to multiple deformations and fatigue resistance are close to those of polyester, and higher than other fibers. It has good heat absorption, and its moisture regain under standard atmospheric conditions is about 4.5%. It has good dyeing properties and can be dyed with disperse dyes, acid dyes and other dyes, but its light and heat resistance are poor. The melting point of nylon 66 is 255°C, and 20% hydrochloric acid can dissolve nylon 66. Generally speaking, nylon 66 feels better than nylon 6, and nylon 66 is more comfortable than nylon 6, but it is difficult to distinguish nylon 6 from nylon 66 on the surface. Spandex yarn has low strength. If the spandex yarn breaks during processing, it will result in coreless yarn. At the same time, spandex yarn has high elasticity, which makes the clothing feel oppressive and restrained, especially for the middle-aged and elderly groups. Nylon 66 filament as the core yarn provides appropriate elasticity while having better strength and abrasion resistance than spandex yarn. Compared with spandex, it is more suitable for elastic core-spun yarn.

[0004] Siro core-spun yarn can be spun on a spinning frame equipped with Siro spinning device and core-spun yarn device. The core yarn of Siro core-spun yarn is fed into the jaws of the front roller through the guide wheel, and two parallel outer fiber rovings enter the three-roller long and short apron drafting device through the collector and are laid flat in the drafting area. When the outer short fiber passes through the front roller, the core yarn is between the two rovings and is always in the middle. The three are combined and twisted and wound onto the spinning bobbin. Traditional core-spun yarn obtains strength through twisting and fiber transfer, while Siro spinning mainly obtains strength through the mutual entanglement between single yarns. Siro spinning feeds finer rovings, and the fiber whiskers are narrower, so that the surface fibers are effectively bound to the yarn body. The mutual entanglement of the two single yarns makes the internal and external transfer of the fibers only half of that of traditional spinning, and the inclination angle between the fibers and the yarn axis is smaller. When the yarn is stretched, the fiber strength utilization rate is higher. In order to make the two rovings fed in parallel transfer and embrace each other better in the drafting front area, the siro-spinning feeding horn makes the two rovings fed in parallel at a close distance, and the covering effect of the core-spun yarn is greatly improved. The hairiness of the siro-spinning core-spun yarn is relatively less than that of the traditional ring-spinning core-spun yarn. The synergistic effect of the double roving feeding, plus the small distance between the two rovings, will not cause large slippage of the fibers in the sliver, so the siro-spinning core-spun yarn has better strand dryness.

[0005] Patent CN211199555U discloses a nylon core-spun yarn with excellent thermal insulation effect. By setting an outer yarn layer that is compositely coated with multiple materials, the yarn core body is made of nylon, the yarn layer is made of pure cotton, and the thermal insulation yarn layer is made of wool and polyester blended yarn, which improves the contact comfort and breathability of the entire yarn surface. While its structure provides better performance, it is relatively complicated in production and is not universal.

[0006] Patent CN213476221U discloses a wear-resistant and flame-retardant aramid-spandex core-spun yarn. Parallel nylon filaments and spandex filaments, combined with aramid fibers, not only provide elasticity for the core-spun yarn, but also make the core-spun yarn have higher strength and excellent flame-retardant properties. This type of yarn is mainly used in special clothing and is not practical for ordinary consumers.

[0007] Patent CN207789906U discloses a down-proof stretch fabric, in which the nylon core-spun yarn used is formed by nylon staple fibers wrapped around nylon filaments. Through structural design, the product has good elasticity and breathability. However, nylon has poor heat resistance and light resistance, and also has poor moisture absorption and dyeing properties. It is difficult for a single component core-spun yarn to meet wearing requirements.

[0008] Patent CN107460587A discloses a method for preparing a core-spun yarn with heat storage and temperature regulation functions. By modifying ring spinning or rotor spinning, a core-spun yarn is obtained with cotton yarn as the core yarn, polyester as the middle covering yarn, and nylon as the outer covering yarn. Although the yarn has the functions of heat storage and temperature regulation, it is difficult for the woven clothing to achieve a skin-friendly effect when nylon is used as the outer covering yarn.

[0009] Patent CN1421556A discloses a modal nylon core-spun yarn and a manufacturing method thereof, using nylon filament (40D / 12f) as the core yarn and cotton or medium-length modal fiber (1.2D×38mm) as the outer fiber, spinning on a jet spinning machine, spinning speed 250m / min, total mechanical draft multiple 172, main draft multiple 35, nozzle-roller distance 38.7mm, feed ratio 0.97, take-up ratio 0.99, collector 2mm, bell mouth 5.6mm, after the improvement of spinning method and process, the quality of the yarn has been improved, but the weight and strip evenness coefficient of variation are still large.

[0010] Patent CN106811849A discloses a soybean fiber and bamboo fiber blended siro core-spun yarn. The ring spinning frame is modified to double the number of hanging spindles and install a spandex yarn active feeding device. To ensure the covering effect, the traverse device needs to be removed and not used. The spinning process: spandex yarn content 9.7%, air pressure 0.1MPa, steel collar PG14254, wire ring 6903 12 / 0, drafting gauge 18×67, total drafting / back zone drafting multiples 60.34 / 1.29, spandex yarn pre-drafting multiples 3.5, jaw 2.5mm ordinary jaw, spindle speed controlled at 10707r / min, front roller speed 100r / min, the yarn produced has a large unevenness rate, which is easy to cause breakage and affect the fabric style in subsequent processing. Summary of the invention

[0011] The purpose of the present invention is to solve the problems existing in the prior art and to provide a nylon 66 siro-spun core-spun yarn and a preparation method thereof. The nylon 66 siro-spun core-spun yarn of the present invention has good yarn quality and strength, is mainly used for the development of woven products, and can be made into clothing products such as shirts, T-shirts, and jeans.

[0012] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0013] Nylon 66 siro-spun core-spun yarn, the core yarn is nylon 66 single or multiple yarns, the outer fiber is regenerated cellulose fiber, or is composed of regenerated cellulose fiber and cotton fiber.

[0014] The core-spun yarn spun by the present invention is siro-spinning, which is different from other inventions. The whiskers have a triangular twisting zone at the output of the front roller. The whiskers are twisted together under tension to form a double-center yarn similar to a ply. When subjected to force, the two whiskers squeeze each other, making it difficult for the fibers to slip off, and the fiber utilization rate is high. Therefore, the siro-spun yarn is characterized by less hairiness, high strength, and good wear resistance. Therefore, the core-spun yarn of the present invention will have the characteristics of less hairiness, high strength, and smooth yarn.

[0015] Siro-spun core-spun yarn is a single yarn with ply properties. Its strength, elongation and uniformity are better than those of ring-spun core-spun yarn. It feels soft and has a good covering effect. The cross-section of Siro-spun core-spun yarn is round, with less hairiness, a smooth surface and good wear resistance.

[0016] As the preferred technical solution:

[0017] As mentioned above, the nylon 66 siro-spun core-spun yarn has a core yarn content of 8-22wt%; the specification of the nylon 66 single-strand yarn is 15-40D / 1F, and the specification of the nylon 66 multi-strand yarn is 15-40D / 12F; when the outer fiber is composed of regenerated cellulose fiber and cotton fiber, the content of regenerated cellulose fiber in the outer fiber is 30-50wt%; the fineness of the regenerated cellulose fiber is 0.9-1.0D.

[0018] The nylon 66 siro-spun core-spun yarn as described above has a yarn breaking strength of 13-19 cN / tex, a yarn evenness CV% of 10.6-12.6%, a yarn evenness variation coefficient CVb% between spindles of 1.2-4.0%, and a +50% kilometer thick section number of 14-49, which can reach the excellent product level of "T / CCTA30201-2022 Cotton Viscose Fiber / Nylon Filament Core-spun Natural Yarn". In addition, the present invention has made a lot of improvements on the poor covering of the core-spun yarn, and the hollow yarn defect, the poor covering yarn defect and the exposed core yarn defect all meet the excellent product standard, that is, the number of defects in 3000 meters is 0. At the same time, the core-spun yarn of the present invention has less hairiness, and the number of hairiness is 38-131 yarns / 100m. The less hairiness, the smoother the yarn.

[0019] The present invention also provides a method for preparing nylon 66 siro-spun core-spun yarn as described in any of the above items, wherein the core yarn is fed into the jaws of the front roller via a guide wheel, and simultaneously two parallel outer fiber rovings are passed through a collector into a three-roller long and short leather ring drafting device and are laid flat in the drafting area. When the outer fiber rovings pass through the front roller, the core yarn passes through the guide frame and enters between the two outer fiber rovings and is always located in the middle. The three are combined, twisted and wound onto a spun yarn bobbin to obtain nylon 66 siro-spun core-spun yarn.

[0020] As the preferred technical solution:

[0021] According to the method described above, the dry basis weight of the outer fiber roving is 3.62g / 10m×2, and the twist coefficient of the outer fiber roving is 100-120.

[0022] When the prior art adopts siro spinning to prepare core-spun yarn, the dry weight of the roving is generally 1.5-2.5g / 10m×2, and the twist coefficient of the roving is generally 75-90 when the prior art adopts siro spinning to prepare core-spun yarn; in order to solve the problem that the prior spinning technology adopts light weight roving, resulting in poor yarn quality and poor coating, the present invention adopts large dry weight of roving and large twist coefficient of roving, and the large internal friction field brought about by the large twist coefficient of roving can enhance the drafting force and fiber control force on the whiskers during drafting. Compared with the effect of the external friction field, the large internal friction force generated by the large twist coefficient of roving has a softer, more balanced and stable effect on the drafting process, and its friction field is a three-dimensional stereo control, and the spinning effect is better.

[0023] According to the method described above, in the spinning process, the total mechanical drafting multiple is 65 to 105 times, the back zone drafting multiple is 1.13 to 1.18 times, and the drafting efficiency is 95 to 98%.

[0024] When the prior art adopts siro spinning to prepare core-spun yarn, the total mechanical drafting multiple in the spinning process is generally 30 to 60 times, the back zone drafting multiple is generally 1.25 to 1.35 times, and the drafting efficiency is generally 89 to 93%; when spinning high-count yarn of cellulose fiber with the same count, a large roving dry weight, a large roving twist coefficient, a small back zone drafting multiple and a large total mechanical drafting multiple are used in coordination with each other, the twist of the roving can be moved to the front jaw, and the drafting speed change point can be moved to the jaw through the internal friction force, and the displacement deviation during high-multiple drafting can be reduced through the internal friction field, and the strength, evenness, thick sections and other indicators of the yarn are better, that is, within a certain range, increasing the roving dry weight and the total mechanical drafting multiple are beneficial to improving the yarn quality.

[0025] According to the method described above, when the drafting rollers of the spinning frame are pressurized, the pressures at the rear, middle and front gears are 160N, 130N and 180N respectively.

[0026] When the prior art uses siro spinning to prepare core-spun yarn, when the rollers are pressurized, the pressures applied at the rear, middle and front levels are 140N, 120N and 160N respectively. The present invention appropriately increases the roller pressure to ensure that there is sufficient holding force to adapt to the drafting force and better control the movement of the fiber.

[0027] According to the method described above, the center of the front roller moves forward by 1 mm, the center of the middle roller moves backward by 1 mm, and the working height of the cradle is 2 mm.

[0028] The present invention optimizes the positions of the front and middle upper rollers and the working height of the cradle and ensures the consistency of the working height of the cradle. In order to reduce the two siro spinning strands from running at the flute suction port, the center forward stroke of the front roller is changed from 2mm in the prior art to 1mm. In order to ensure the dryness of the yarn, the center backward movement of the middle roller is changed from 2mm in the prior art to 1mm. The working height of the cradle is adjusted from 3mm in the prior art to 2mm. In order to effectively control the movement of the fibers during the drafting process, form a stable and good drafting, prevent the fibers from slipping and improve the CV value of the yarn dryness, the jaws formed by the rubber rollers and the rollers must have sufficient holding force on the fibers to overcome the friction resistance between the fibers, thereby causing relative displacement between the fibers to form drafting. The present invention sets the working height of the cradle to 2mm to ensure that the jaws formed by the rubber rollers and the rollers have sufficient holding force on the fibers. The working height of the cradle is inversely proportional to the pressure on the cradle. The lower the height, the greater the pressure, and the greater the pressure, the greater the holding force of the jaws formed by the rubber rollers and the rollers.

[0029] In the method described above, the core wire passes through the wire guide frame and enters between the two outer fiber rovings, which means that the core wire passes through the wire guide frame, through the rear wire guide wheel and the front wire guide wheel, and enters between the two outer fiber rovings.

[0030] Conventional core-spun yarn generally adopts the method of front wire guide wheel and rear wire guide hook. The present invention adopts the method of front and rear wire guide wheels. The wire guide wheels will rotate under the tension of the yarn, are not easy to wear, and can reduce the defect of high defects caused by the gathering of flying fibers on the wire guide hook.

[0031] In the method described above, the process parameters of the spinning process include: the spinning twist is 50 to 120, and the spindle speed is 10000 to 14000 r / min.

[0032] In the method described above, a PVC tube is sleeved on the wire guide rod through which the core wire passes before feeding into the front roller jaws. The present invention can ensure that the tension of the core wire is moderate by selecting a suitable diameter of the PVC tube (20 mm), an enveloping angle of the PVC tube wire guide rod, an arrangement of the PVC tube and a wire guide direction.

[0033] Beneficial effects:

[0034] (1) The nylon 66 core yarn is not drawn, but its tension and running direction are controlled by the guide rod, guide hook and guide wheel so that it can be smoothly wrapped by the whiskers spit out from the jaws. The two rovings are introduced into the drawing area of ​​the spinning frame in parallel through the double bell mouths. After being drawn separately in parallel, two fiber bundles with a certain distance are formed at the jaws of the front roller. They are lightly twisted for the first time, and then meet the fed core yarn at the natural convergence point. The combined twisted yarns are wound onto the yarn tube to form the siro core-spun yarn.

[0035] (2) The spacing between the rovings affects the size of the twisting triangle. As the spacing between the two rovings increases, the length of the single yarn on the upper side of the convergence point increases, and the twist on the single yarn also increases. The yarn strands have less hairiness and good wear resistance. The spacing between the two rovings should not be too large, otherwise, the number of broken ends increases. The spacing between the two rovings should be determined based on the length of the outer fiber and the coating effect. In order to improve the coating effect of the finished yarn, the spacing between the two rovings should be 3 to 5 mm, which can accommodate a core wire. The spacing between the two rovings of the present invention is 3 mm. The core wire is fed from the middle of the angle between the two yarns. During twisting, the core wire is always in the center of the yarn strands, so that the siro core-spun yarn has a good coating effect.

[0036] (3) The spun yarn of the present invention adopts large drafting process parameters and small back-zone drafting multiples, the total mechanical drafting multiples are 65 to 105 times, the back-zone drafting multiples are 1.13 to 1.18 times, and the drafting efficiency is 95 to 98%.

[0037] (4) The present invention optimizes roller pressure, and the rear, middle and front pressure gears are medium, small and medium; the cradle pressure distribution is optimized, and the cradle working height is 2 mm.

[0038] (5) The strength and coating effect of the Siro-spun core-spun yarn of the present invention are better than those of the traditional core-spun yarn. Therefore, for yarns with the same purpose, the twist coefficient of the Siro-spun core-spun yarn can be lower than that of the similar ring-spun core-spun yarn. The twist of the spun yarn is between 50 and 120, the spindle speed is between 10,000 and 14,000 r / min, and the nylon 66 content is 8 to 22 wt%.

[0039] (6) In addition to ensuring the correct position of the filaments and whiskers, the air ring during spinning must also be strictly controlled. The yarn guide hook is not allowed to have grooves. The time when the wire ring is on the machine must be closely monitored. If it is severely worn, it is very easy to form peeled yarn (core yarn) or wool yarn. The product of the present invention uses a steel collar model of PG1-4254, a steel ring model of BSJM1EMgc5# for the 16-count core-spun yarn, a steel ring model of UWL 2# for the 21-count core-spun yarn, and a steel ring model of UWL 1 / 0 for the 32-count core-spun yarn. In the actual production process, the models of the steel collar and the steel ring should be adjusted according to the actual production environment. They are for reference only and are not used as a unified standard.

[0040] (7) The present invention sets a suitable cradle gauge, which is the distance between the cradle support rod and the front roller, affecting the forward tilt of the top roller (such as Figure 1 As shown, generally 1.5 ~ 3.5mm), the forward inclination of the leather roller means that the center line of the roller and the center line of the leather roller are not in a straight line. The forward inclination of the leather roller presses down the roving whiskers, affecting the surrounding angle between the whiskers and the roller. This surrounding angle affects the breakage of the spun yarn. The surrounding angle of ring spinning is larger, and the surrounding angle of siro spinning is smaller. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a configuration diagram of the roller of the present invention. DETAILED DESCRIPTION

[0042] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0043] The detection methods of the relevant properties of the nylon 66 siro-spun core-spun yarn prepared in the following embodiments are as follows:

[0044] Testing method for yarn breaking strength: Group standard "Cotton viscose fiber / nylon filament core-spun natural yarn (T / CCTA30201-2022)"

[0045] Testing method for CV% of yarn evenness: Group standard "Cotton viscose fiber / nylon filament core-spun natural yarn (T / CCTA30201-2022)"

[0046] Testing method for the coefficient of variation CVb% between spindles: Group standard "Cotton viscose fiber / nylon filament core-spun natural yarn (T / CCTA30201-2022)"

[0047] +50% Testing method for the number of thick sections per kilometer: Group standard "Cotton viscose fiber / nylon filament core-spun natural yarn (T / CCTA30201-2022)"

[0048] Defect number detection method: Group standard "Cotton viscose fiber / nylon filament core-spun natural yarn (T / CCTA 30201-2022)";

[0049] Testing method for hairiness number: Group standard "Cotton viscose fiber / nylon filament core-spun natural yarn (T / CCTA 30201-2022)".

[0050] Example 1

[0051] A method for preparing nylon 66 siro-spun core-spun yarn, the specific steps are as follows:

[0052] (1) Raw material preparation:

[0053] Core yarn: Nylon 66 single strand yarn with specification of 15D / 1F;

[0054] Outer fiber: regenerated cellulose fiber with a fineness of 0.9D;

[0055] (2) The core yarn is fed into the jaws of the front roller through the godet wheel, and at the same time, two parallel outer fiber rovings are fed into the three-roller long and short apron drafting device through the collector and laid flat in the drafting area. When the outer fiber roving passes through the front roller, the core yarn passes through the godet frame, the rear godet wheel and the front godet wheel and enters between the two outer fiber rovings, and is always located in the middle. The three are combined, twisted and wound onto the spun yarn bobbin to obtain nylon 66 siro spinning core-spun yarn; wherein:

[0056] The dry weight of the outer fiber roving is 3.62g / 10m×2, the twist coefficient is 100; the spacing between the two rovings is 3mm;

[0057] The total mechanical drafting ratio is 105 times, the back zone drafting ratio is 1.13 times, and the drafting efficiency is 95%;

[0058] When the drafting rollers of the spinning machine are pressurized, the pressures at the rear, middle and front gears are 160N, 130N and 180N respectively; the roller gauges are 18.5mm (front to middle) and 45mm (middle to rear);

[0059] The center of the front roller is 1mm forward, the center of the middle roller is 1mm backward, the working height of the cradle is 2mm, the cradle gauge is 178mm, and the front roller is tilted 1.5mm;

[0060] The twist of the spinning is 120, and the spindle speed is 10500r / min;

[0061] Ring model PG14254, wire traveler model BSJM1EMgc 5#;

[0062] A PVC tube is placed on the wire guide rod through which the core wire passes before entering the front roller jaws.

[0063] The final nylon 66 siro-spun core-spun yarn has a count of 16, a yarn breaking strength of 18.3 cN / tex, a yarn evenness CV% of 11.29%, a yarn evenness variation coefficient CVb% between spindles of 2.6%, a +50% number of thick sections per kilometer of 29, a number of defects per 3000 meters of 0, a number of hairiness of 38 yarns / 100 m, and a core yarn content of 8 wt%.

[0064] Example 2

[0065] A method for preparing nylon 66 siro-spun core-spun yarn, the specific steps are as follows:

[0066] (1) Raw material preparation:

[0067] Core yarn: Nylon 66 multi-strand yarn with specification of 20D / 12F;

[0068] Outer fiber: regenerated cellulose fiber with a fineness of 0.9D;

[0069] (2) The core yarn is fed into the jaws of the front roller through the godet wheel, and at the same time, two parallel outer fiber rovings are fed into the three-roller long and short apron drafting device through the collector and laid flat in the drafting area. When the outer fiber roving passes through the front roller, the core yarn passes through the godet frame, the rear godet wheel and the front godet wheel and enters between the two outer fiber rovings, and is always located in the middle. The three are combined, twisted and wound onto the spun yarn bobbin to obtain nylon 66 siro spinning core-spun yarn; wherein:

[0070] The dry weight of the outer fiber roving is 3.62g / 10m×2, and the twist coefficient is 105; the spacing between the two rovings is 3mm;

[0071] The total mechanical drafting ratio is 95 times, the back zone drafting ratio is 1.15 times, and the drafting efficiency is 96%;

[0072] When the drafting rollers of the spinning machine are pressurized, the pressures at the rear, middle and front gears are 160N, 130N and 180N respectively; the roller gauges are 18.5mm (front to middle) and 45mm (middle to rear);

[0073] The center of the front roller is 1mm forward, the center of the middle roller is 1mm backward, the working height of the cradle is 2mm, the cradle gauge is 178mm, and the front roller is tilted 1.5mm;

[0074] The twist of the spinning yarn is 116, and the spindle speed is 11000r / min;

[0075] Ring model PG14254, wire traveler model BSJM1EMgc 5#;

[0076] A PVC tube is placed on the wire guide rod through which the core wire passes before entering the front roller jaws.

[0077] The final nylon 66 siro-spun core-spun yarn has a count of 16, a yarn breaking strength of 16.6 cN / tex, a yarn evenness CV% of 10.85%, a yarn evenness variation coefficient CVb% between spindles of 1.2%, a +50% number of thick sections per kilometer of 15, a number of defects per 3000 meters of 0, a number of hairiness of 49 yarns / 100m, and a core yarn content of 15wt%.

[0078] Example 3

[0079] A method for preparing nylon 66 siro-spun core-spun yarn, the specific steps are as follows:

[0080] (1) Raw material preparation:

[0081] Core yarn: Nylon 66 single strand yarn with specification of 30D / 1F;

[0082] Outer fiber: regenerated cellulose fiber with a fineness of 1.0D;

[0083] (2) The core yarn is fed into the jaws of the front roller through the godet wheel, and at the same time, two parallel outer fiber rovings are fed into the three-roller long and short apron drafting device through the collector and laid flat in the drafting area. When the outer fiber roving passes through the front roller, the core yarn passes through the godet frame, the rear godet wheel and the front godet wheel and enters between the two outer fiber rovings, and is always located in the middle. The three are combined, twisted and wound onto the spun yarn bobbin to obtain nylon 66 siro spinning core-spun yarn; wherein:

[0084] The dry weight of the outer fiber roving is 3.62g / 10m×2, and the twist coefficient is 103; the spacing between the two rovings is 3mm;

[0085] The total mechanical drafting ratio is 88 times, the back zone drafting ratio is 1.13 times, and the drafting efficiency is 95%;

[0086] When the drafting rollers of the spinning machine are pressurized, the pressures at the rear, middle and front gears are 160N, 130N and 180N respectively; the roller gauges are 18.5mm (front to middle) and 45mm (middle to rear);

[0087] The center of the front roller is 1mm forward, the center of the middle roller is 1mm backward, the working height of the cradle is 2mm, the cradle gauge is 178mm, and the front roller is tilted 1.5mm;

[0088] The twist of the spun yarn is 50, and the spindle speed is 12000r / min;

[0089] Ring model PG14254, wire traveler model UWL 2#;

[0090] A PVC tube is placed on the wire guide rod through which the core wire passes before entering the front roller jaws.

[0091] The final nylon 66 siro-spun core-spun yarn has a count of 21, a yarn breaking strength of 16.1 cN / tex, a yarn evenness CV% of 10.65%, a yarn evenness variation coefficient CVb% between spindles of 3.4%, a +50% number of thick sections per kilometer of 16, a number of defects per 3000 meters of 0, a number of hairiness of 54 yarns / 100m, and a core yarn content of 18wt%.

[0092] Example 4

[0093] A method for preparing nylon 66 siro-spun core-spun yarn, the specific steps are as follows:

[0094] (1) Raw material preparation:

[0095] Core yarn: Nylon 66 multi-strand yarn with specification of 30D / 2F;

[0096] Outer fiber: 50wt% regenerated cellulose fiber with a fineness of 0.9D + 50wt% combed cotton;

[0097] (2) The core yarn is fed into the jaws of the front roller through the godet wheel, and at the same time, two parallel outer fiber rovings are fed into the three-roller long and short apron drafting device through the collector and laid flat in the drafting area. When the outer fiber roving passes through the front roller, the core yarn passes through the godet frame, the rear godet wheel and the front godet wheel and enters between the two outer fiber rovings, and is always located in the middle. The three are combined, twisted and wound onto the spun yarn bobbin to obtain nylon 66 siro spinning core-spun yarn; wherein:

[0098] The dry weight of the outer fiber roving is 3.62g / 10m×2, and the twist coefficient is 112; the spacing between the two rovings is 3mm;

[0099] The total mechanical drafting ratio is 100 times, the drafting ratio in the rear zone is 1.18 times, and the drafting efficiency is 98%;

[0100] When the drafting rollers of the spinning machine are pressurized, the pressures at the rear, middle and front gears are 160N, 130N and 180N respectively; the roller gauges are 18.5mm (front to middle) and 45mm (middle to rear);

[0101] The center of the front roller is 1mm forward, the center of the middle roller is 1mm backward, the working height of the cradle is 2mm, the cradle gauge is 178mm, and the front roller is tilted 1.5mm;

[0102] The twist of the spinning is 120, and the spindle speed is 13500r / min;

[0103] Ring model PG14254, wire traveler model UWL 2#;

[0104] A PVC tube is placed on the wire guide rod through which the core wire passes before entering the front roller jaws.

[0105] The final nylon 66 siro-spun core-spun yarn has a count of 21, a yarn breaking strength of 13.1 cN / tex, a yarn evenness CV% of 12.5%, a yarn evenness variation coefficient CVb% between spindles of 2.7%, a +50% number of thick sections per kilometer of 49, a number of defects per 3000 meters of 0, a number of hairiness of 103 yarns / 100m, and a core yarn content of 20wt%.

[0106] Example 5

[0107] A method for preparing nylon 66 siro-spun core-spun yarn, the specific steps are as follows:

[0108] (1) Raw material preparation:

[0109] Core yarn: Nylon 66 single strand yarn with specification of 35D / 1F;

[0110] Outer fiber: 50wt% regenerated cellulose fiber with a fineness of 1.0D + 50wt% combed cotton;

[0111] (2) The core yarn is fed into the jaws of the front roller through the godet wheel, and at the same time, two parallel outer fiber rovings are fed into the three-roller long and short apron drafting device through the collector and laid flat in the drafting area. When the outer fiber roving passes through the front roller, the core yarn passes through the godet frame, the rear godet wheel and the front godet wheel and enters between the two outer fiber rovings, and is always located in the middle. The three are combined, twisted and wound onto the spun yarn bobbin to obtain nylon 66 siro spinning core-spun yarn; wherein:

[0112] The dry weight of the outer fiber roving is 3.62g / 10m×2, and the twist coefficient is 118; the spacing between the two rovings is 3mm;

[0113] The total mechanical drafting ratio is 105 times, the back zone drafting ratio is 1.13 times, and the drafting efficiency is 97%;

[0114] When the drafting rollers of the spinning machine are pressurized, the pressures at the rear, middle and front gears are 160N, 130N and 180N respectively; the roller gauges are 18.5mm (front to middle) and 45mm (middle to rear);

[0115] The center of the front roller is 1mm forward, the center of the middle roller is 1mm backward, the working height of the cradle is 2mm, the cradle gauge is 178mm, and the front roller is tilted 1.5mm;

[0116] The twist of the spinning yarn is 103, and the spindle speed is 12600r / min;

[0117] Ring model PG14254, wire traveler model UWL 1 / 0;

[0118] A PVC tube is placed on the wire guide rod through which the core wire passes before entering the front roller jaws.

[0119] The final nylon 66 siro-spun core-spun yarn has a count of 32, a yarn breaking strength of 15 cN / tex, a yarn evenness CV% of 12.59%, a yarn evenness variation coefficient CVb% between spindles of 3.7%, a +50% number of thick sections per kilometer of 49, a number of defects per 3000 meters of 0, a number of hairiness of 95 yarns / 100 m, and a core yarn content of 16 wt%.

[0120] Example 6

[0121] A method for preparing nylon 66 siro-spun core-spun yarn, the specific steps are as follows:

[0122] (1) Raw material preparation:

[0123] Core yarn: Nylon 66 multi-strand yarn with specification of 40D / 12F;

[0124] Outer fiber: 50wt% regenerated cellulose fiber with a fineness of 0.9D + 50wt% combed cotton;

[0125] (2) The core yarn is fed into the jaws of the front roller through the godet wheel, and at the same time, two parallel outer fiber rovings are fed into the three-roller long and short apron drafting device through the collector and laid flat in the drafting area. When the outer fiber roving passes through the front roller, the core yarn passes through the godet frame, the rear godet wheel and the front godet wheel and enters between the two outer fiber rovings, and is always located in the middle. The three are combined, twisted and wound onto the spun yarn bobbin to obtain nylon 66 siro spinning core-spun yarn; wherein:

[0126] The dry weight of the outer fiber roving is 3.62g / 10m×2, and the twist coefficient is 120; the spacing between the two rovings is 3mm;

[0127] The total mechanical drafting ratio is 65 times, the back zone drafting ratio is 1.16 times, and the drafting efficiency is 98%;

[0128] When the drafting rollers of the spinning machine are pressurized, the pressures at the rear, middle and front gears are 160N, 130N and 180N respectively; the roller gauges are 18.5mm (front to middle) and 45mm (middle to rear);

[0129] The center of the front roller is 1mm forward, the center of the middle roller is 1mm backward, the working height of the cradle is 2mm, the cradle gauge is 178mm, and the front roller is tilted 1.5mm;

[0130] The twist of the spinning yarn is 96, and the spindle speed is 14000r / min;

[0131] Ring model PG14254, wire traveler model UWL 1 / 0;

[0132] A PVC tube is placed on the wire guide rod through which the core wire passes before entering the front roller jaws.

[0133] The final nylon 66 siro-spun core-spun yarn has a count of 32, a yarn breaking strength of 15 cN / tex, a yarn evenness CV% of 10.99%, a yarn evenness variation coefficient CVb% between spindles of 3.9%, a number of thick sections per +50% km of 14, a number of defects per 3000 meters of 0, a number of hairiness of 131 yarns / 100 m, and a core yarn content of 22 wt%.

Claims

1. A method for preparing nylon 66 siro-spun core-spun yarn, characterized in that: The core yarn is fed into the jaws of the front roller through the godet wheel, and at the same time, two parallel outer fiber rovings are fed into the three-roller long and short apron drafting device through the collector and laid flat in the drafting area. When the outer fiber roving passes through the front roller, the core yarn passes through the guide frame and enters between the two outer fiber rovings, always in the middle. The three are combined, twisted and wound onto the spun yarn bobbin to obtain nylon 66 siro-spun core-spun yarn; The dry weight of the outer fiber roving is 3.62g / 10m×2, and the twist coefficient of the outer fiber roving is 100-120; In the spinning process, the total mechanical drafting ratio is 65 to 105 times, and the drafting ratio in the back zone is 1.13 to 1.18 times; The center of the middle roller is moved back by 1mm, and the working height of the cradle is 2mm; The core yarn of nylon 66 siro-spun core yarn is single or multiple strands of nylon 66, and the outer covering fiber is regenerated cellulose fiber, or is composed of regenerated cellulose fiber and cotton fiber.

2. The method for preparing nylon 66 siro-spun core-spun yarn according to claim 1, characterized in that: In the spinning process, the drafting efficiency is 95 to 98%.

3. The method for preparing nylon 66 siro-spun core-spun yarn according to claim 1, characterized in that: When the drafting rollers of the spinning frame are pressurized, the pressures at the rear, middle and front gears are 160N, 130N and 180N respectively.

4. The method for preparing nylon 66 siro-spun core-spun yarn according to claim 1, characterized in that: The center punch of the front roller is 1mm.

5. The method for preparing nylon 66 siro-spun core-spun yarn according to claim 1, characterized in that: The core wire passes through the wire guide frame and enters between the two outer fiber rovings, which means that the core wire passes through the wire guide frame, through the rear wire guide wheel and the front wire guide wheel, and enters between the two outer fiber rovings.

6. The method for preparing nylon 66 siro-spun core-spun yarn according to claim 1, characterized in that: The process parameters of the spinning process include: spinning twist 50 to 120, spindle speed 10000 to 14000 r / min.

7. The method for preparing nylon 66 siro-spun core-spun yarn according to claim 1, characterized in that: The content of core yarn in nylon 66 siro-spun core-spun yarn is 8-22wt%; the specification of nylon 66 single-strand yarn is 15-40D / 1F, and the specification of nylon 66 multi-strand yarn is 15-40D / 12F; when the outer covering fiber is composed of regenerated cellulose fiber and cotton fiber, the content of regenerated cellulose fiber in the outer covering fiber is 30-50wt%; the fineness of the regenerated cellulose fiber is 0.9-1.0D.

8. The method for preparing nylon 66 siro-spun core-spun yarn according to claim 7, characterized in that: The breaking strength of nylon 66 siro-spun core-spun yarn is 13-19 cN / tex, the yarn evenness CV% is 10.6-12.6%, the coefficient of variation CVb% between spindles is 1.2-4.0%, the number of thick sections per +50% kilometer is 14-49, the number of defects per 3000 meters is 0, and the number of hairiness is 38-131 pieces / 100m.

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