Composite yarn and preparation method and application thereof

Abstract

The invention provides a composite yarn and a preparation method and application thereof. The composite yarn is characterized in that two short-fiber roving strands are fed from a pre-drafting mechanism, and are respectively drafted and carded to be stretched into short-fiber strands; inorganic fiber filaments are fed from the yarn guide holes, the inorganic fiber filaments and the two drafted short fiber strands are twisted by the twisting leather roller to form at least two strands of spun yarns, the at least two strands of spun yarns are combined at the yarn guide hook, and the composite yarn with the inorganic fiber filaments wrapped by the short fiber strands is spun. The composite yarn has high-temperature tolerance and flexibility at the same time, has no twist on the whole, and perfectly solves the problems of splitting and brittle failure of inorganic fiber filaments caused by twisting in common ring spinning. In addition, the preparation method does not need flexible treatment like that of conventional ring spinning yarn, so that tedious treatment steps and related cost are omitted, and pollution to the environment is reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of self-twist spinning, and particularly relates to a composite yarn and a preparation method and application thereof. BACKGROUND

[0002] Yarn is a kind of textile product processed from various textile fibers to a certain fineness, which is used for weaving, rope making, thread making, knitting and embroidery, etc., and is divided into short fiber yarns and continuous filaments, etc.

[0003] Traditional self-twist yarns have a remarkable feature that they have no twist as a whole, and thus are very soft. The softness of self-twist yarns makes them perform well in many applications. Compared with traditional yarns, they can provide higher comfort because they do not feel rough or have a twisted feeling. This makes self-twist yarns have a unique advantage in manufacturing comfortable clothing, bedding and home textiles.

[0004] Inorganic fiber raw materials are widely used as high-temperature resistant fiber raw materials, with basalt being the most prominent. However, basalt fibers usually severely lack comfort, and are prone to brittle fracture or splitting when subjected to bending or impact forces due to their high modulus. Therefore, during the spinning process, flexible fiber raw materials are often used to coat them.

[0005] There are mainly two kinds of existing flexible processing solutions for yarns. One is to use flexible fiber raw materials from the fiber raw material; the other direction is to modify the existing fiber raw materials physically, chemically or biologically to give them flexibility. Such methods are complicated in process, high in cost, and pollute the environment, which has great disadvantages. Moreover, the yarns spun by traditional inorganic high-temperature resistant fiber raw materials through ring spinning still have the problem of incompatibility in performance and flexibility in high-temperature environments.

[0006] Therefore, it is of important theoretical and practical significance to study how to combine self-twist spinning with inorganic fibers to improve the performance of yarns, reduce production costs, reduce environmental impact, and provide more comfortable and durable textiles. SUMMARY

[0007] The present application aims to solve the above-mentioned problems of the prior art, and provides a composite yarn and a preparation method and application thereof.

[0008] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0009] The first object of the present application is to provide a composite yarn and a preparation method thereof, which adopts a S300 self-twist spinning machine, the self-twist spinning machine comprising a short fiber roving sliver, a pre-drafting mechanism, a main drafting mechanism, a twisting leather roller and a composite yarn arranged in sequence along the direction of the raw material roving sliver, the main drafting mechanism comprising a limiting leather roller, a filament positioning hole, a filament, a tension regulator and a guide hole, the filament positioning hole being arranged at the entrance of the limiting leather roller, the tension regulator controlling the tension of the filament, a guide hook being arranged between the twisting leather roller and the groove drum, two short fiber roving slivers being fed from the pre-drafting mechanism, respectively stretched into short fiber slivers after drafting and combing; an inorganic fiber filament being fed from the guide hole, the inorganic fiber filament and the two drafted short fiber slivers forming at least two yarns under the twisting of the twisting leather roller, the at least two yarns meeting at the guide hook to spin the composite yarn in which the inorganic fiber filament is covered by the short fiber sliver, the covering mode of the inorganic fiber filament having two modes: when the inorganic fiber filament and one of the short fiber slivers form a first yarn under the twisting of the twisting leather roller, the other short fiber sliver forms a second yarn under the twisting of the twisting leather roller, the first yarn and the second yarn meet at the guide hook to form a untwist triangle area, the untwist and combination spinning the self-twist yarn; when the inorganic fiber filament is arranged in parallel between the two short fiber slivers, three yarns are formed after the twisting of the twisting leather roller, the three yarns meet at the guide hook, the untwist and combination spinning the self-twist yarn.

[0010] Further, the short fiber is aramid fiber, and the aramid fiber roving specification is 430-450 tex.

[0011] Further, the inorganic fiber filament is basalt filament, and the specification of the basalt filament is 12-13 tex.

[0012] Further, the mass ratio of the aramid fiber roving to the basalt filament is 35:65-37:63.

[0013] Further, the distance between the twisting leather roller and the limiting leather roller is 30-35 mm, the spinning speed is 20-25 m / min, and the yarn cycle length is kept at 60-80 mm to output from the guide hook.

[0014] Further, the pre-drafting mechanism comprises a plurality of rollers, and the distance between two adjacent rollers is 80-100 mm.

[0015] Further, the gap distance between the limiting leather roller and the belt in the main drafting mechanism is 25-30 mm, and the filament positioning hole is located in the gap.

[0016] Further, the ratio of the draft of the aramid fiber roving is 10-50 times.

[0017] The second object of the present application is to provide a composite yarn prepared by the above method.

[0018] Further, the coating layer of the composite yarn is composed of aramid short fibers with flame retardancy, and the embedded core layer is basalt filament with high temperature resistance, and the composite yarn includes any one of self-twist yarn Z twist zone, self-twist yarn no twist zone and self-twist yarn S twist zone.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] (1) The composite yarn and its preparation method provided by the present application feed two roving strands of short fibers from the pre-drafting mechanism, stretch them into short fiber strands after drafting and carding respectively; feed inorganic fiber filaments from the guide hole, and form at least two yarns under the twisting of the twisting skin roller, and the at least two yarns are combined at the guide hook to spin the composite yarn in which the inorganic fiber filaments are covered by the short fiber strands. The present application solves the problem of incompatibility of the performance and flexibility of the yarn spun by the traditional inorganic high-temperature resistant fiber raw material through ring spinning in high temperature environment, and solves the problem of how to embed inorganic fibers into self-twist spinning.

[0021] (2) The composite yarn provided by the present application adopts self-twist spinning technology. The composite yarn as a whole has no twist, which perfectly solves the problem of splitting and brittle fracture of basalt filaments in ordinary ring spinning.

[0022] (3) The composite yarn provided by the present application is prepared by self-twist spinning technology, so it does not need to be flexible like conventional ring spun yarn, thereby saving the cumbersome processing steps and related costs.

[0023] (4) The composite yarn provided by the present application saves the flexible processing step in the preparation process, further reduces the pollution to the environment, and is consistent with the green development concept advocated by the country.

[0024] (5) The weft knitted fabric is prepared by using the composite yarn prepared by the present application, and the balanced stress of the composite yarn itself makes the knitted fabric have no rolling problem, thereby reducing the difficulty of subsequent sewing and other processing procedures, and ensuring the standard consistency of the clothing specifications. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The structure diagram of the S300 self-twist spinning machine for preparing the composite yarn of the present application;

[0026] Figure 2a Structure of the main drafting mechanism

[0027] Figure 2b Flow chart of filament feeding

[0028] Figure 3 Structure of staple fiber covering filament in the phase self-twist yarn process

[0029] Figure 3a Structure of Z twist zone of the composite yarn prepared by the phase self-twist yarn process

[0030] Figure 3b Structure of no twist zone of the composite yarn prepared by the phase self-twist yarn process

[0031] Figure 3c Structure of S twist zone of the composite yarn prepared by the phase self-twist yarn process

[0032] Figure 4 Structure of staple fiber covering filament in the in-phase self-twist yarn process

[0033] Figure 4a Structure of Z twist zone of the composite yarn prepared by the in-phase self-twist yarn process

[0034] Figure 4b Structure of no twist zone of the composite yarn prepared by the in-phase self-twist yarn process

[0035] Figure 4c Structure of S twist zone of the composite yarn prepared by the in-phase self-twist yarn process

[0036] Figure 5 Picture of the composite yarn prepared in Example 1, twist 40 twist / 10 cm

[0037] Figure 6 Picture of the composite yarn prepared in Example 2, twist 40 twist / 10 cm

[0038] Figure 7a Picture of the ring spun yarn strength varying with twist

[0039] Figure 7b Picture of the composite yarn prepared in Example 1, strength varying with strain

[0040] Figure 7c Picture of the basalt filament strength varying with strain

[0041] Figure 8a Picture of the flexibility test result of the composite yarn prepared in Example 1

[0042] Figure 8bA picture of a weft-knitted fabric knitted using the composite yarn prepared in Example 1;

[0043] Figure 9a A picture of a weft-knitted fabric knitted using the composite yarn prepared in Example 1;

[0044] Figure 9b A picture of a weft-knitted fabric knitted using the composite yarn prepared in Example 1.

[0045] In the figure, 1 is a roving sliver of staple fibers, 2 is a filament, 3 is a groove cylinder, 4 is a pre-drafting mechanism, 5 is a main drafting mechanism, 51 is a limiting apron, 52 is a filament positioning hole, 53 is a tension regulator, and 54 is a guide hole. DETAILED DESCRIPTION

[0046] In order to make the objectives, technical solutions, and advantages of the present application clearer, the embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, in which identical or similar reference numerals represent identical or similar elements or elements having identical or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as a limitation of the present application. Unless otherwise specified, the raw materials and instruments and equipment in the embodiments of the present application are all purchased through commercial channels.

[0047] REFERENCE Figure 1 A structure schematic diagram of an S300 self-twist spinning machine for preparing the composite yarn of the present application. The S300 self-twist spinning machine comprises a roving sliver of staple fibers 1, a pre-drafting mechanism 4, a main drafting mechanism 5, a twisting apron 6, and a composite yarn 3, which are sequentially arranged along the direction of the roving sliver of the raw material. The main drafting mechanism 5 comprises a limiting apron 51, a filament positioning hole 52, a filament 2, a tension regulator 53, and a guide hole 54. The filament positioning hole 52 is arranged above the limiting apron 51, and the tension regulator 53 controls the tension of the filament 2. After passing through the guide hole 54 directly above, the tension of the filament 2 is controlled by the tension regulator 53, and then the filament is accurately fed into the filament positioning hole 52. The filament 2 passes through the filament positioning hole 52 and reaches the limiting apron 51. The roving sliver of staple fibers is drafted into a staple fiber sliver after passing through the pre-drafting mechanism 4 and the main drafting mechanism 5, and the staple fiber sliver is sent into the limiting apron 51 together with the embedded filament 2 before passing through the limiting apron 51. At this time, the staple fiber sliver is subjected to secondary drafting, and the filament is only fed into the twisting apron 6 together with the staple fiber sliver because the filament does not pass through all the devices of the main drafting mechanism 5. Under the twisting of the twisting apron 6, the in-phase or phase self-twist yarn is formed. The output speed of the twisting apron can be 1.04 times that of the limiting apron, and thus the staple fiber sliver after being plied with the filament is also subjected to a certain drafting effect.

[0048] In some embodiments, the distance between the twisting roller 6 and the limiting roller 51 is 30-35 mm, the spinning speed is 20-25 m / min, and the yarn cycle length is kept at 60-80 mm from the 1 / 3 of the guide hook 1. The distance between the rollers of the pre-drafting mechanism 4 is 80-100 mm. The distance between the rollers of the main drafting mechanism 5 is 120 mm, and the distance between the limiting roller of the main drafting mechanism 5 and the belt is 25-30 mm. The feeding position of the filament is within the gap of 25-30 mm. The distance between the limiting roller 51 and the twisting roller 6 is 30 mm.

[0049] Reference Figure 2a Figure 1 is a schematic diagram of the partial structure of the S300 self-twist spinning machine of the present application. The filament 2 is fed into the limiting roller 51 through the filament positioning hole 52 for drafting, and after being fed into the twisting roller 6, the filament is combined with the staple yarn at the guide hook 7 after twisting.

[0050] Reference Figure 2b Figure 2 is a flow chart of the filament 2 feeding process of the present application. After passing through the guide hole 54, the filament 2 is then adjusted in tension by the tension regulator 53, and then fed into the limiting roller 51 through the filament positioning hole 52 for drafting.

[0051] The composite yarn prepared by the present application has the feature that the covering layer is composed of staple fibers, and the embedded core layer is a filament. The fineness of the self-twist spun yarn is mainly determined by the drafting ratio and the feeding weight, and the drafting ratio is composed of two parts, one is the pre-drafting mechanism determined by the gear set, which needs to change the number of teeth of the gear to change the pre-drafting multiple, and the other is the main drafting mechanism, the multiple of which needs to be adjusted in the control panel.

[0052] The above-mentioned composite yarn is spun in the self-twist spinning manner. Due to the characteristics of the self-twist spinning manner, the spun yarn regularly distributes S-twist regions, no-twist regions, and Z-twist regions, and the yarn as a whole has no twist, which solves the problem that inorganic high-temperature resistant fiber yarns such as basalt fiber cannot have flexibility.

[0053] The preparation method and performance characteristics of the composite yarn of the present application are described in detail below with specific examples.

[0054] In some embodiments, the raw materials used are 430-450 tex aramid roving and 12.6 tex basalt filament, the pre-drafting multiple is 10 times, the main drafting multiple is 12 times, the filament 2 is fed after the end of the limiting roller 51, and is accurately fed into the middle of the staple fiber sliver through the filament positioning hole 52 above the limiting roller 51, so that the filament overlaps with the staple fiber sliver, and then is twisted together by the twisting roller 6. The two composite yarns meet at the guide hook and are twisted together by self-twist to form a composite yarn, which is then wound on the bobbin by the winding mechanism.

[0055] After the aramid roving is fed into the raw material inlet, it is fed into the pre-drafting mechanism 4 by the traction device (e.g., Figure 1 As shown, this is roller drafting, achieving the first drafting stage. After pre-drafting, the roving becomes a thin fiber bundle. In this configuration, all rollers are steel grooved rollers, with the middle roller having a diameter of 32mm and the remaining rollers having a diameter of 50mm. The roller surfaces are on the same plane. In the three upper roller rows, the front and rear rows are nitrile-coated rollers, each with a diameter of 55mm, while the middle row is a bubble roller. The front and rear rollers form the drafting zone, and a bundler is installed after each roller row for bundling. Pressure is applied using a mechanical front-locking spring rocker arm. The roller center distance is adjustable according to the fiber length and count.

[0056] The main drafting mechanism 5 is a roller drafting system that achieves the second drafting stage. In this configuration, all three lower rollers are steel grooved rollers with a diameter of 31.75 mm, and their surfaces are on the same plane. The main drafting zone is located between the front and middle rollers, with a fixed roller center distance of 109.5 mm. The rear zone has a minimum roller center distance of 108 mm and a maximum of 165 mm, increasing in 19 mm increments. The rear zone drafting ratio is 1.11, and the total drafting ratio ranges from 10 to 50. The front condenser is close to the belt roller and moves laterally by 1.5 mm.

[0057] In some embodiments, high-temperature resistant basalt filaments are used as embedded filaments 2. These high-temperature resistant basalt inorganic fibers can give the resulting fiber yarns good high-temperature resistance. Furthermore, the basalt filaments have extremely high strength, which can give the resulting fiber yarns high strength.

[0058] In some embodiments, the first and second yarns are spun from flame-retardant aramid staple fiber roving. The aramid has a certain flame-retardant property, which can further improve the high-temperature resistance of the resulting fiber yarns.

[0059] Example 1

[0060] This embodiment provides a method for preparing composite yarn.

[0061] The specific steps of the phase self-twisting yarn spinning process are as follows:

[0062] Two aramid short fibers (40mm) pass through the pre-draft mechanism 4 into the first roller of the main draft mechanism 5, and meet the basalt filament at a position 110-20mm away from the limiting apron roller 51. The spacing between the limiting apron roller and the belt in the main draft mechanism 5 is 25-30mm. The basalt filament accurately overlaps the center of the left short fiber through the pre-set filament feeding hole, and is held and transported by the limiting apron roller 51 to the twisting apron roller 6 for twisting. The spacing between the limiting apron roller 51 and the twisting apron roller 6 is 30mm. The two aramid short fibers form a first yarn and a second yarn after the first draft and the second draft.

[0063] Reference Figure 3 The first yarn on the left and the filament are twisted together under the influence of the twisting stick to form a self-twisting single yarn, which is recorded as a third yarn. The second yarn on the right forms an aramid single yarn independently and forms a certain phase difference with the self-twisting single yarn under the influence of the second guide hook. At the first guide hook, the second yarn and the third yarn meet to form a untwisting triangle area. The more stable the untwisting triangle area is, the more stable the self-twisting yarn formed is, and the self-twisting yarn is twisted into a strand. The two self-twisting composite yarns are wound on the groove drum 3.

[0064] The composite yarn prepared in this embodiment is structurally two yarns. In the spinning process of the yarn, one short fiber is first twisted with the filament to form a single yarn, and a first composite process occurs. Then, the single yarn is twisted with another short fiber to form a second composite process.

[0065] Reference Figures 3a-3c The spun composite yarn regularly distributes Z-twist regions, twist-free regions, and S-twist regions, and the composite yarn has no twist as a whole.

[0066] Reference Figure 5 The twist of the composite yarn prepared in this embodiment is 40 twists / 10cm. As can be clearly seen from the figure, the outer layer of the basalt filament uniformly winds the two aramid short fibers.

[0067] Example 2

[0068] The embodiment provides a preparation method of a composite yarn.

[0069] The same-phase self-twisting yarn spinning process is adopted, and the specific steps are as follows:

[0070] Two aramid short fibers (40mm) pass through the pre-draft mechanism 4 into the first roller of the main draft mechanism 5, and meet the basalt filament at a position 10-20mm away from the limiting apron roller 10. The distance between the limiting apron roller and the apron belt in the main draft mechanism 5 is 25-30mm. The basalt filament is positioned between the two aramid short fibers through the pre-set filament feeding hole, and is held by the limiting apron roller 51 to be transported to the twisting apron roller 6 to be twisted. The distance between the limiting apron roller 51 and the twisting apron roller 6 is 30mm. The two aramid short fibers form first and second yarns respectively after the first and second draft.

[0071] Reference Figure 4 The filament is located between the first and second yarns, and meets at the third guide hook to be twisted into a 3-ply composite yarn. The formed 3-ply twisted composite yarn is wound on the groove drum 3.

[0072] The composite yarn prepared in the embodiment is a 3-ply yarn. In the spinning process of the yarn, two short fibers and one filament are twisted respectively, and finally combined into a yarn at the guide hook. This process includes two independent twisting and combining, which are the twisting of the short fibers and the combining of the twisted short fibers and the filament.

[0073] Reference Figures 4a-4c The spun composite yarn regularly distributes Z-twist regions, twist-free regions, and S-twist regions, and the composite yarn has no twist as a whole.

[0074] Reference Figure 6 The twist of the composite yarn prepared in the embodiment is 40 twists / 10cm. As can be clearly seen from the figure, the basalt filament is an integral whole with one of the aramid short fibers, and is twisted with the other aramid short fiber.

[0075] In order to better illustrate the beneficial effects of the composite yarn provided by the present application, the applicant has carried out the following research:

[0076] 1. Comparative study on the performance of the composite yarn prepared in Example 1 and Example 2

[0077] Place under standard atmospheric conditions (air temperature 20±2℃, relative humidity 65±2%) for 48h. Then test the performance indicators of the composite yarn under the same temperature and humidity conditions.

[0078] Hair test: according to China Textile Industry Standard FZ / T01086-2000, use YG171B-2 hair tester to test the hair of the yarn, the test speed is 30m / min, and the test section length is 10m. Test 10 sections continuously for each yarn.

[0079] Yarn evenness test: According to the national standard GB / T3292-1997, the evenness and defects of the yarn were tested by USTER ME100 evenness tester; the test speed was 400 m / min, and the test time of each sample was 1 min.

[0080] Mechanical property test: the tensile strength of the sample was tested by INSTRON5943 universal strength testing machine (Illinois Tool Works Inc., Massachusetts, USA). The clamping distance was 100 mm, the test speed was 100 mm / min, and the test number of the sample was 10 times.

[0081] (1) The hairiness test results are shown in Table 1.

[0082] Table 1. Comparison of hairiness of different composite yarns

[0083]

[0084] In structure, there is a phase difference in the phase self-twist yarn, S twist and S twist self-twist form S twist zone, no twist zone and S twist form S twist zone with weak self-twist effect, Z twist zone and S twist zone cancel each other out due to opposite untwist torque, forming no twist zone, but at this time the no twist zone of each single yarn fiber is tightly held. The same phase self-twist yarn has no phase difference, so the S twist zone combines with the S twist zone to form S twist strand, the no twist zone combines with the no twist zone to form no twist zone, and the Z twist zone combines with the Z twist zone to form Z twist strand. The no twist zone of the same phase self-twist yarn is not tightly held. The outer layer of the same phase self-twist yarn has no filament covering, and the surface fiber yarn body has no restraint, so that the short fibers are more easily exposed to the surface of the yarn body during twisting to form a large amount of hairiness.

[0085] (2) The yarn evenness parameter test results of the composite yarns are shown in Table 2.

[0086] Table 2. Comparison of yarn evenness parameters of different composite yarns

[0087]

[0088] The phase self-twist yarn has tight fiber holding, so the yarn evenness is better than that of the same phase self-twist yarn.

[0089] (3) Comparison of tensile properties of composite yarns.

[0090] The breaking strength of the same phase composite yarn was tested by INSTRON5943 universal strength testing machine to be 708 cN, and the breaking strength of the phase composite yarn was 670 cN.

[0091] The strength of basalt is larger, and the orientation of filament in yarn body is higher, the strength of yarn is larger. In the same phase self-twist yarn, the filament is fed along the fiber axis, and the two single yarns are wrapped in the outer layer of the filament, so the strength of the same phase composite yarn is higher.

[0092] From the above comparison, due to the different ways of combining filament and staple fiber, the performance of the yarn will appear slightly different. Because the composite phase self-twist yarn has undergone two times of wrapping, the structure is more stable, the hairiness is less, and the evenness is better. But in strength, because the filament is not arranged along the axis of the yarn, the utilization rate of strength is slightly lower than that of the same phase composite yarn.

[0093] Comparative Example 1

[0094] The comparative example is a composite yarn prepared by using traditional ring spinning.

[0095] Because the structure of self-twist yarn is similar to that of sirospun, a sirospun yarn with similar structure is prepared on a ring spinning frame, i.e. two rovings are fed. Basalt filaments are fed to the front roller, and the feeding position is between the two fiber must bar spacings to spin a core-spun yarn. The raw materials used are consistent with those used in self-twist spinning. At the same time, a ring spun yarn with the same fineness is spun, and the mass ratio of aramid roving to basalt filament is 35:65 to 37:63.

[0096] The strength and flexibility of the composite yarn prepared in the comparative example and the composite yarn prepared in the comparative example are compared.

[0097] The tensile strength test of the sample is carried out by using INSTRON5943 universal strength testing machine (Illinois Tool Works Inc., Massachusetts, USA). The clamping distance is 100 mm, the test speed is 100 mm / min, and the test number of the sample is 10 times.

[0098] The flexibility detection method is: the test of the drape of the yarn is to place the yarns of the same length on the table edge and let them naturally drape, observe the angle between the yarn at the drape point and the vertical direction from the side, and judge the drape of the yarns.

[0099] Reference Figures 7a-7c The strength of the ring spun yarn changes with the twist as shown in Figure 7a The breaking strength of the yarn increases with the increase of the twist, because the axial breaking strength of basalt filament as a typical inorganic high-temperature resistant fiber material is large, but the tangential stress is small. When the twist of the yarn is low, the force on the basalt filament when it is stretched is mostly the tensile force in the axial direction, at this time the breaking strength of the yarn is large, with the increase of the twist, the force on the basalt filament when it is stretched is gradually converted into tangential stress, at this time the breaking strength of the yarn is reduced.

[0100] The strength of the self-twist yarn changes with the strain as shown inFigure 7b As shown in Fig. 2, the strength of the self-twist yarn is close to 600 cN. Figure 7b As shown in Fig. 2, the strength of the self-twist yarn is close to 600 cN. Figure 7a The ring spun yarn in Fig. 1 has the highest strength of 1350 cN, because the self-twist yarn has a twist-free zone, as shown in Fig. 2, in which the aramid staple fiber is not twisted and cannot be held together, and the strength is provided by the basalt filament, so Figure 3b The curve trend of Fig. 1 is similar to the strain change graph of the basalt filament in Fig. 2. Figure 7b The curve trend of Fig. 1 is similar to the strain change graph of the basalt filament in Fig. 2. Figure 7c The curve trend of Fig. 1 is similar to the strain change graph of the basalt filament in Fig. 2.

[0101] Referring to Fig. 4, the flexibility detection result graph of the composite yarn prepared in Example 1, the angle between the phase composite yarn and the vertical direction is about 55°-60°. Figure 8a Referring to Fig. 5, the flexibility detection result graph of the composite yarn prepared in Comparative Example 1, the angle between the ring spun composite yarn and the vertical direction is 71°-75°.

[0102] Figure 8b By comparing the bending angles of the yarns, it can be concluded that the flexibility of the composite yarn prepared in Example 1 is better than that of the ring spun yarn with the same fineness.

[0103] By comparing the bending angles of the yarns, it can be concluded that the flexibility of the composite yarn prepared in Example 1 is better than that of the ring spun yarn with the same fineness.

[0104] Example 3

[0105] The composite yarn prepared in Example 1 was used to prepare a weft-knitted fabric.

[0106] According to the conventional knitting method in the art, the weft-knitted fabric was knitted by using the composite yarn as the raw material on a weft-knitting machine, as shown in Fig. 6, the edge of the weft-knitted fabric is flat and even. Figure 9a The same knitting method was used, and the composite yarn prepared in Comparative Example 1 was used as the raw material to knit a weft-knitted fabric, as shown in Fig. 7, the edge of the weft-knitted fabric is severely rolled.

[0107] Figure 9b As can be seen by comparison, the balanced stress of the composite yarn prepared in the application makes the knitted fabric have no rolling problem, thereby reducing the difficulty of subsequent sewing and other processing procedures, and ensuring the standard consistency of the garment specifications

[0108] The above-mentioned matters not covered are applicable to the prior art.

[0109] The above-mentioned matters not covered are applicable to the prior art.

[0110] ​​Although some specific embodiments of the present application have been described in detail by way of example with reference to the drawings, it is to be understood that the above examples are intended to be illustrative only and are not intended to limit the scope of the present application, and that various modifications and changes can be made by those skilled in the art to the particular embodiments described without departing from the spirit and scope of the present application. It is intended that the scope of the present application be limited only by the broadest interpretation of the appended claims to be accorded under 35 U.S.C. § 112.

Claims

1. A method for preparing a composite yarn using a S300 self-twist spinning machine, the self-twist spinning machine comprising a staple fiber roving sliver (1) of raw material, a pre-drafting mechanism (4), a main drafting mechanism (5), a twisting leather roller (6) and a groove drum (3) arranged in sequence along the direction of the staple fiber roving sliver, the main drafting mechanism (5) comprising a limiting leather roller (51), a filament positioning hole (52), a filament (2), a tension regulator (53) and a guide hole (54), the filament positioning hole (52) being arranged above the limiting leather roller (51), the tension regulator (53) controlling the tension of the filament (2), a guide hook (7) being arranged between the twisting leather roller (6) and the groove drum (3), characterized in that, Two short fiber roving slivers are fed from the pre-drafting mechanism (4), respectively stretched into short fiber slivers after drafting; the inorganic fiber filaments are fed from the guide hole (54), and the inorganic fiber filaments and the two drafted short fiber slivers are twisted into at least two yarns under the twisting of the twisting roller (6), and the at least two yarns are combined at the guide hook (7) to spin the composite yarn in which the inorganic fiber filaments are covered by the short fiber slivers, and the inorganic fiber filaments are covered in two ways: when the inorganic fiber filaments and one of the short fiber slivers are twisted into a first yarn under the twisting of the twisting roller (6), and the other short fiber sliver is twisted into a second yarn under the twisting of the twisting roller (6), the first yarn and the second yarn are combined at the guide hook (7) to form a untwist triangle area, and the self-twist yarn is spun after untwist combination; when the inorganic fiber filaments are arranged in parallel between the two short fiber slivers, three yarns are formed after the inorganic fiber filaments are twisted by the twisting roller (6), and the three yarns are combined at the guide hook (7) to spin the self-twist yarn with the same phase after untwist combination.

2. The production method according to claim 1, wherein The short fiber is aramid fiber, and the specification of the aramid fiber roving is 430-450 tex; the inorganic fiber filament is basalt filament, and the specification of the basalt filament is 12-13 tex.

3. The production method according to claim 2, wherein The mass ratio of the aramid fiber roving to the basalt filament is 35:65-37:

63.

4. The production method according to claim 3, wherein The distance between the twisting roller (6) and the limiting roller (51) is 30-35 mm, the spinning speed is 20-25 m / min, and the cycle length of the yarn is kept to 60-80 mm to be output from the guide hook (7).

5. The production method according to claim 3, wherein The pre-drafting mechanism (4) comprises a plurality of rollers, and the distance between two adjacent rollers is 80-100 mm.

6. The production method according to claim 3, wherein The distance between the limiting roller and the belt in the main drafting mechanism (5) is 25-30 mm, and the filament positioning hole (52) is located in the gap.

7. The production method according to claim 3, wherein The draft ratio of the sliver of the aramid fiber roving is 10-50 times.

8. A composite yarn, characterized by The preparation method is prepared by any one of claims 2-7.

9. The composite yarn of claim 8, wherein, The composite yarn comprises any one of self-twist yarn Z twist area, self-twist yarn no twist area and self-twist yarn S twist area.

10. A weft-knitted fabric prepared by using the composite yarn of claims 8-9.

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