Composite fiber and preparation method thereof, elastic profiled fiber and textile

Abstract

The invention discloses a composite fiber, an elastic profiled fiber, a preparation method of the elastic profiled fiber and a textile, a first component, a second component and a third component are used as raw materials, the first component and the second component have different shrinkage rates during curing, and the third component is separated from the first component and the second component during melting contact; by adopting the specific spinning assembly, the composite fiber can be continuously and stably spun and extruded, and the spinning assembly uniquely designs a distribution runner, so that three components with different properties can easily control the pressure and the flowing state in the flowing process, the mutual influence is reduced, the excellent continuous productivity is further ensured, and the production efficiency is improved. Meanwhile, the composite fiber prepared by the method can be split into fibers with specific structures, the fibers not only can have superfine radial dimensions, but also have remarkable elasticity, glossiness and strength such as tear strength, and the preparation of high-quality textiles is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of spinning, and in particular to a composite fiber, an elastic special-shaped fiber, a preparation method thereof and a textile. Background Art

[0002] At present, the textile industry generally defines fibers with a single filament fineness of less than 0.44dtex as ultrafine fibers. The characteristics of ultrafine fibers mainly include soft and delicate feel and good flexibility. There are many methods for producing ultrafine fibers, such as direct spinning and bicomponent spinning. The direct spinning method is relatively simple, but in actual application, it is difficult to spin fibers below 0.44 dtex, and it is not easy to produce on a large scale. The bicomponent spinning method is currently the most widely used and studied method, which can be roughly divided into two categories: composite spinning and blended spinning. Among them, the composite spinning method is the most widely used. The specific operation is to spin two or more fiber-forming polymers into composite fibers, and then dissolve and remove one component in the composite fiber to separate the components to obtain ultrafine fibers. For example, non-adhesive melt polyester and polyamide are made into composite fibers, and then ultrafine fibers can be obtained after peeling. Common methods include first preparing sea-island type fibers, one of which is a dispersed phase (i.e., island component) and the other is a continuous phase (i.e., sea component). The island component is contained in the sea component in the shape of ultrafine fibers. The cross-section of the ultrafine fiber is distributed in an island shape, and its long axis is parallel to the composite fiber. The sea component is dissolved and removed to obtain ultrafine fibers generated by the island component. However, the ultrafine fibers currently prepared still have defects such as insufficient elasticity, poor gloss, and relatively poor strength such as tear strength, which limits their applicability.

[0003] It should be noted that the information disclosed in the above background technology section is only used to understand the background of the present application, so the background technology section of the present invention may contain background information about the problem or environment of the present invention, but not necessarily describe the prior art. Therefore, the content contained in the background technology section is not an admission of the applicant to the prior art. Summary of the invention

[0004] The object of the present invention is to overcome one or more deficiencies in the prior art and to provide an improved composite fiber and elastic shaped fiber, so as to improve at least one aspect of the elasticity, glossiness, and strength such as tear strength of the prepared ultrafine fibers.

[0005] The present invention also provides a textile product comprising the composite fiber and the elastic shaped fiber.

[0006] In order to achieve the above object, a technical solution adopted by the present invention is: a method for preparing a composite fiber, the preparation method comprising:

[0007] The first component, the second component and the third component are used as raw materials, the first component and the second component have different shrinkage rates when solidified, and the third component respectively undergoes phase separation with the first component and the second component when in molten contact;

[0008] Using a spinneret assembly to spin extrude the composite fiber;

[0009] The spinneret assembly comprises a distribution plate and a spinneret formed with spinneret holes, the distribution plate comprises a first flow channel for simultaneously introducing the first component and the second component into the spinneret holes, and a second flow channel for introducing the third component into the spinneret holes, and the axis of the first flow channel is perpendicular to the axis of the second flow channel;

[0010] The area of ​​the cross section of the first flow channel perpendicular to the length direction is S1, the length of the first flow channel is L1, and the following conditions are met:

[0011] And 5≤a≤20;

[0012] The area of ​​the cross section of the second flow channel perpendicular to the length direction is S2, the length of the second flow channel is L2, and the following conditions are met:

[0013] Among them, and 1≤b≤10;

[0014] There are multiple first flow channels and multiple second flow channels respectively, and two adjacent first flow channels are separated by one second flow channel. The multiple second flow channels are separated from each other or their respective axial lines intersect at the same point, and the orthographic projections of the first flow channel and the second flow channel are both located within the orthographic projection range of the entrance of the spinneret.

[0015] According to some preferred aspects of the present invention, the outlets of the plurality of first flow channels are respectively distributed on the circumference of a first circle, and the inlets of the plurality of second flow channels are respectively distributed on the circumference of a second circle;

[0016] The center of the first circle coincides with the center of the second circle, or the straight line where the two centers are located is parallel to the axis of the first flow channel.

[0017] Furthermore, the diameter of the first circle is 1 / 3-3 / 4 of the diameter of the second circle.

[0018] In some preferred embodiments of the present invention, a cross section of the first flow channel perpendicular to the length direction is circular.

[0019] In some preferred embodiments of the present invention, a cross section of the second flow channel perpendicular to the length direction is square.

[0020] In some preferred embodiments of the present invention, a fan-shaped area is formed between two adjacent second flow channels, and the first flow channel is located at the centroid of the fan-shaped area.

[0021] In some preferred embodiments of the present invention, the cross section of the spinneret hole perpendicular to the length direction is circular.

[0022] According to some preferred aspects of the present invention, the distribution plate further includes a third flow channel, which surrounds the outer circumference of the plurality of second flow channels and is respectively connected to the plurality of second flow channels.

[0023] Furthermore, the distribution plate further includes at least one fourth flow channel and a plurality of fifth flow channels, the at least one fourth flow channel is respectively connected with the third flow channels, and the fifth flow channels are connected with the first flow channels in a one-to-one correspondence.

[0024] Furthermore, the fourth flow channel includes a first sub-flow channel and a second sub-flow channel which are connected to each other, the axis line of the first sub-flow channel, the axis line of the fifth flow channel and the axis line of the first flow channel are all parallel, the second sub-flow channel is connected to the third flow channel and its outlet is staggered with the inlet of the second flow channel.

[0025] According to some preferred aspects of the present invention, L1, L2, S1, and S2 satisfy the following conditions:

[0026] And 1.5≤c≤5.

[0027] In some preferred embodiments of the present invention, the difference between the intrinsic viscosities of the first component and the second component is 0.15-0.7 dL / g.

[0028] In some preferred embodiments of the present invention, the mass ratio of the first component to the second component is 10:90 to 90:10.

[0029] In some preferred embodiments of the present invention, the total feed mass ratio of the first component and the second component to the feed mass ratio of the third component is 90:10 to 50:50.

[0030] According to some specific aspects of the present invention, the first component and the second component are independently selected from PET (Chinese name: polyethylene terephthalate), PBT (Chinese name: polybutylene terephthalate) or PTT (Chinese name: polypropylene terephthalate), and the third component is PA6 (Chinese name: nylon 6), COPET (Chinese name: polyethylene terephthalate copolymer, alkali-soluble polyester), PE (Chinese name: polyethylene) or PP (polypropylene).

[0031] In some preferred embodiments of the present invention, the preparation method is carried out using the FDY process, and the parameters of the FDY process are: the box spinning temperature of the first component is 240-295°C, the box spinning temperature of the second component is 240-295°C, the box spinning temperature of the third component is 240-285°C, the cooling temperature is 19-23°C, the cooling wind pressure is 15-35Pa, the network pressure is 0.25-0.4MPa, the speed of one roller is 1600-2800m / min, the temperature of one roller is 60-92°C, the speed of the second roller is 4000-6000m / min, the temperature of the second roller is 95-155°C, and the winding speed is 3900-5800m / min.

[0032] Another technical solution provided by the present invention is a composite fiber made by the composite fiber preparation method described above.

[0033] According to the present invention, the breaking strength of the composite fiber is greater than or equal to 2.4 cN / dtex as measured according to GB / T 14344-2008. In some embodiments, the breaking strength is 2.6-3.5 cN / dtex.

[0034] In some embodiments of the present invention, the elongation at break of the composite fiber is 10%-30% as measured according to GB / T 14344-2008.

[0035] In some embodiments of the present invention, the linear density of the composite fiber is 20-200 dtex as measured in accordance with GB / T 14343-2008.

[0036] In some embodiments of the present invention, the dyeing uniformity of the composite fiber is greater than or equal to level 4.5 as measured in accordance with GB / T 6508-2015.

[0037] In some embodiments of the present invention, the boiling water shrinkage of the composite fiber is 6%-12% as measured according to GB / T 6505-2017.

[0038] In some embodiments of the present invention, the curl shrinkage rate of the composite fiber is 20%-40% as measured according to GB / T 6506-2017.

[0039] Another technical solution provided by the present invention is: a composite fiber, the composite fiber comprising a first component, a second component and a third component, the first component and the second component having different shrinkage rates when solidified, and the third component and the first component and the second component respectively undergo phase separation when mixed and melted;

[0040] The cross section of the composite fiber perpendicular to the length direction includes a plurality of monocomponent regions and bicomponent regions, two adjacent bicomponent regions are separated by one monocomponent region, the monocomponent region occupies at most 50% of the area of ​​the cross section perpendicular to the length direction, and the plurality of monocomponent regions are separated from each other or connected to each other at the center of the cross section perpendicular to the length direction;

[0041] The single-component region includes the third component, and the dual-component region includes the first component and the second component. The first component and the second component are arranged in parallel, and both the first component and the second component are in contact with the third component.

[0042] According to some preferred and specific aspects of the present invention, the two-component region is a fan-shaped structure.

[0043] According to some preferred and specific aspects of the present invention, the cross section perpendicular to the length direction has a hollow structure, and the two-component area is a remaining structure after removing a part adjacent to the center of the fan-shaped structure.

[0044] According to some preferred aspects of the present invention, in the two-component region, the portion where the first component contacts the second component is arc-shaped.

[0045] Another technical solution provided by the present invention is an elastic shaped fiber, wherein the elastic shaped fiber is obtained by removing the third component from the composite fiber described above.

[0046] In some embodiments of the present invention, the removal method includes mechanical stripping, alkaline solution stripping or dissolution removal.

[0047] In some embodiments of the present invention, the removal method is alkaline solution dissolution treatment or alkaline solution stripping, for example, sodium hydroxide aqueous solution can be used for treatment at 80-100° C. for a period of time, which can be 10-30 minutes.

[0048] Another technical solution provided by the present invention is: a textile, at least a part of which is composed of the composite fiber mentioned above, or the elastic shaped fiber mentioned above.

[0049] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0050] Based on the fact that the currently prepared ultrafine fibers still have defects such as insufficient elasticity, poor gloss, and relatively poor strength such as tear strength, the inventors of the present invention innovatively provide a composite fiber and a preparation method thereof. The composite fiber of the present invention can be used to make ultrafine fibers with greatly reduced radial dimensions, and the ultrafine fibers have achieved significant improvements in at least one aspect of elasticity, gloss, and strength such as tear strength. More specifically, the present invention can achieve excellent improvement in comprehensive performance. For example, the prepared ultrafine fibers have excellent elasticity, gloss, strength and other properties at the same time. In addition, the composite fiber of the present invention can be used directly, so that the product has the properties of ultrafine elastic fibers and a third component at the same time. The composite fiber can also be made into cloth and the third component can be dissolved and removed to directly obtain a product made of ultrafine elastic fibers. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 Schematic diagram of the structure of the spinneret assembly in an embodiment of the present invention;

[0052] Figure 2 for Figure 1 The enlarged schematic diagram of point A in the middle;

[0053] Figure 3 This is a schematic diagram of the structure of a distribution plate in an embodiment of the present invention;

[0054] Figure 4 for Figure 3 The enlarged schematic diagram of point B in the middle;

[0055] Figure 5 for Figure 4 Another schematic diagram of the distribution flow channel shown;

[0056] Figure 6 It is a schematic diagram of the internal flow passage of the distribution plate after being cut open in an embodiment of the present invention;

[0057] Figure 7 for Figure 6 The enlarged schematic diagram of the center C;

[0058] Figure 8 Schematic diagram of the internal flow channel of the spinneret assembly after being cut open in an embodiment of the present invention;

[0059] Fig. 9 for Figure 8 The enlarged schematic diagram of point D in the middle;

[0060] Fig.10 It is a partial schematic diagram of the first flow channel and the second flow channel;

[0061] Fig.11 Schematic diagram of another feeding structure of three components in an embodiment of the present invention;

[0062] Fig.12 FIG. 1 is a schematic cross-sectional view of a composite fiber, an elastic shaped fiber, and a single-component fiber formed by a third component in an embodiment of the present invention; wherein: Fig.12 (a) is a schematic cross-sectional view of the composite fiber. Fig.12 (b) is a schematic cross-sectional view of elastic shaped fibers. Fig.12 (c) is a schematic cross-sectional view of a fiber formed by the third component;

[0063] Fig.13 FIG2 is a second cross-sectional schematic diagram of a composite fiber, an elastic shaped fiber, and a single component fiber formed by a third component in an embodiment of the present invention; wherein: Fig.13 (a) is a schematic cross-sectional view of the composite fiber. Fig.13 (b) is a schematic cross-sectional view of elastic shaped fibers. Fig.13 (c) is a schematic cross-sectional view of a fiber formed by the third component;

[0064] Fig.14 FIG3 is a third cross-sectional schematic diagram of a composite fiber, an elastic shaped fiber, and a single component fiber formed by a third component in an embodiment of the present invention; wherein: Fig.14 (a) is a schematic cross-sectional view of the composite fiber. Fig.14 (b) is a schematic cross-sectional view of elastic shaped fibers. Fig.14 (c) is a schematic cross-sectional view of a fiber formed by the third component;

[0065] Fig.15 FIG4 is a schematic cross-sectional view of the composite fiber, the elastic shaped fiber and the single component fiber formed by the third component in the embodiment of the present invention; wherein: Fig.15 (a) is a schematic cross-sectional view of the composite fiber. Fig.15 (b) is a schematic cross-sectional view of elastic shaped fibers. Fig.15 (c) is a schematic cross-sectional view of a fiber formed by the third component;

[0066] In the accompanying drawings, numerals are as follows: 10, first component; 20, second component; 30, third component; 40, spinneret assembly; 41, distribution plate; 411, first flow channel; 412, second flow channel; 413, third flow channel; 414, fourth flow channel; 4141, first sub-flow channel; 4142, second sub-flow channel; 415, fifth flow channel; 416, first component introduction slot; 417, second component introduction slot; 418, third component introduction slot; 419, solid middle; 42, spinneret; 421, spinneret hole; 50, composite fiber; 51, single component area; 52, two-component area; 53, hollow structure; 60, elastic shaped fiber; 70, single component fiber. DETAILED DESCRIPTION

[0067] At present, the main method for preparing ultrafine fibers is to first prepare sea-island fibers, and then dissolve and remove the sea component to obtain ultrafine fibers generated by the island component. In practice, the inventors of the present invention have used this idea to make elastic ultrafine fibers. The island component is replaced by, for example, a two-component PET with a high and low viscosity difference, and the elasticity of the ultrafine fibers is achieved through the different curing shrinkage rates of the two components. However, experiments have found that there are large fluctuations in the spinning process using conventional spinnerets, such as uneven spinning pressure and spinning failures, and the spinning success rate is not high, which is not conducive to large-scale industrial production. In addition, even if ultrafine fibers are prepared, the strength of the prepared ultrafine fibers, such as tear strength and glossiness, are not good, or there are abnormalities in strand dryness and uneven dyeing, which greatly limits their actual application.

[0068] Based on this, the present invention provides an improved spinning assembly, which can be used to continuously and stably prepare composite fibers. The composite fibers have the radial size of normal fibers. By removing the single-component fibers formed by the third component in the composite fibers, ultrafine fibers with excellent effects in at least elasticity, glossiness, strength such as tear strength, etc. can be obtained. The ultrafine fibers are composed of a first component and a second component. The first component and the second component have different shrinkage rates during solidification. The third component exhibits phase separation with the first component and the second component respectively during molten contact. The third component can be stripped by dissolution removal, alkali solution stripping (non-dissolution), mechanical stripping, etc. Furthermore, the third component can be, for example, alkali-soluble fibers, water-soluble fibers, etc. The single-component fibers obtained by splitting can also have special morphologies, such as "M" shape, "S" shape, etc. The "M" shape fiber has an extremely large specific surface area and a strong hygroscopic effect.

[0069] In the embodiment of the present invention, the first component and the second component are independently selected from PET (Chinese name: polyethylene terephthalate), PBT (Chinese name: polybutylene terephthalate) or PTT (Chinese name: polypropylene terephthalate), and the third component includes but is not limited to PA6 (Chinese name: nylon 6), COPET (Chinese name: polyethylene terephthalate copolymer), PE (Chinese name: polyethylene), PP (polypropylene), etc. Further, the difference between the intrinsic viscosity of the first component and the second component is 0.15-0.7 dL / g, for example, it can be 0.15 dL / g, 0.2 dL / g, 0.25 dL / g, 0.3 dL / g, 0.35 dL / g, 0.4 dL / g, 0.45 dL / g, 0.5 dL / g, 0.55 dL / g, 0.6 dL / g, 0.65 dL / g, 0.7 dL / g, etc.; the mass ratio of the first component to the second component is 10:90-90:10, for example, it can be 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, 60:40, 65:35, 70:30, 75:25, 80:20, 85:15, etc.; the total feed mass ratio of the first component to the second component and the feed mass ratio of the third component is 90:10-50:50, for example, it can be 50:50, 60:40, 65:35, 70:30, 75:25, 80:20, 85:15, etc.

[0070] The preparation of the composite fiber of the present invention can be carried out using the FDY process, and the parameters of the FDY process are: the box spinning temperature of the first component is 240-295°C, the box spinning temperature of the second component is 240-295°C, the box spinning temperature of the third component is 240-285°C, the cooling temperature is 19-23°C, the cooling wind pressure is 15-35Pa, the network pressure is 0.25-0.4MPa, the speed of one roller is 1600-2800m / min, the temperature of one roller is 60-92°C, the speed of the second roller is 4000-6000m / min, the temperature of the second roller is 95-155°C, and the winding speed is 3900-5800m / min.

[0071] In practice, it is found that, since the three components introduced in the present invention have different properties, the conventional melt distribution method, that is, the conventional through-hole melt distribution method, is used, which makes it easy to have uneven melt distribution during the spinning process, with a large difference from the expected component content, and even leakage of slurry occurs, resulting in failure to spin normally. Even if composite fibers are accidentally spun, the performance of the ultrafine fibers obtained by separation is still unsatisfactory in all aspects. Based on this, the present invention uniquely designs the spinning assembly:

[0072] The spinneret assembly comprises a distribution plate and a spinneret plate having spinneret holes, the distribution plate comprises a first flow channel for simultaneously introducing a first component and a second component into the spinneret holes, and a second flow channel for introducing a third component into the spinneret holes, wherein the axis of the first flow channel is perpendicular to the axis of the second flow channel;

[0073] The area of ​​the cross section of the first flow channel perpendicular to the length direction is S1, the length of the first flow channel is L1, and the following conditions are met:

[0074] And 5≤a≤20;

[0075] The area of ​​the cross section of the second flow channel perpendicular to the length direction is S2, the length of the second flow channel is L2, and the following conditions are met:

[0076] And 1≤b≤10;

[0077] There are multiple first flow channels and multiple second flow channels respectively, and two adjacent first flow channels are separated by a second flow channel. The multiple second flow channels are separated from each other or their respective axis lines intersect at the same point. The orthographic projections of the first flow channel and the second flow channel are both located within the orthographic projection range of the entrance of the spinneret.

[0078] Combine the following Figures 1 to 15 The technical solution of the present invention is further described. In the process of preparing the composite fiber of the present invention, the structural schematic diagram of the spinneret assembly used is shown in FIG. Figures 1 to 11 The cross-sectional schematic diagrams of the composite fiber, elastic shaped fiber and the single component fiber formed by the third component are respectively shown in Figures 12 to 15 .

[0079] The spinneret assembly 40 includes a distribution plate 41 and a spinneret 42 stacked in sequence from top to bottom. The distribution plate 41 is used to introduce various components. The spinneret 42 is formed with spinneret holes 421. The spinneret holes 421 are used to receive and spray various components introduced by the distribution plate 41 to form composite fibers 50.

[0080] Figure 1 to Figure 2A schematic diagram of the distribution flow channel for introducing the first component, the second component and the third component in the initial stage on the distribution plate 41 is schematically shown. Only one is given as an example, and a form of composite fiber can be obtained; specifically, the first component is introduced into the fifth flow channel 415 through the first component introduction groove 416, and the second component is introduced into the fifth flow channel 415 through the second component introduction groove 417. The first component introduction groove 416 and the second component introduction groove 417 are respectively connected to the fifth flow channel 415, and the two are at an angle, which is an acute angle, and the angle of the acute angle can be 10°-75°, and one first component introduction groove 416, one second component introduction groove 417 and one fifth flow channel 415 constitute a first component introduction groove 416, one second component introduction groove 417 and one fifth flow channel 415. A two-component combination, the combination for introducing the two components has multiple components and roughly forms a circle, the fifth flow channel 415 is located in the middle of the circle, the first component introduction groove 416 and the second component introduction groove 417 are respectively extended from the outside to the inside, and at the same time, a plurality of third component introduction grooves 418 are also arranged on the distribution plate 41, and the third component introduction grooves 418 are arranged in a ring shape. A third component introduction groove 418 can be respectively arranged on both sides of the aforementioned circle, and the two third component introduction grooves 418 surround the aforementioned circle in the middle, so that the third component can be introduced at both ends respectively, which not only realizes that the third component can be introduced in sufficient amount, but also helps to disperse the pressure of the introduction of the third component, and avoid excessive pressure caused by introduction from a single position.

[0081] Further, see Figure 3 to Figure 4 , which makes the bottom of the distribution plate 41 face upward, and a distribution diagram of the flow channels at the bottom of the distribution plate 41 can be seen, which has a plurality of first flow channels 411 and a plurality of second flow channels 412, and two adjacent first flow channels 411 are separated by a second flow channel 412, and two adjacent second flow channels 412 are separated by a first flow channel 411. Figure 4The multiple second flow channels 412 in the first flow channel 411 converge at a point (an area) in the middle, and the single-component fiber formed in this way will be a whole with an obvious special-shaped structure, and the first component and the second component introduced simultaneously by the first flow channel 411 will be parallel to the spinneret hole, so that the two-component fiber formed by the first component and the second component will be confined between the gaps of the single-component fiber, and the third flow channel 413 is annularly arranged, that is, the third component in the third flow channel 413 can be simultaneously supplied to the multiple second flow channels 412 by means of the annular arrangement, and the third component in the third flow channel 413 is annularly arranged. The third component in the third flow channel 413 flows in through the first sub-flow channel 4141 and the second sub-flow channel 4142 of the fourth flow channel in sequence. Two fourth flow channels can be symmetrically arranged, and the third component can be introduced into the third flow channel 413 from both ends at the same time, which is beneficial for each position in the third flow channel 413 to be quickly filled with the third component, and then each second flow channel 412 can receive the introduction of the third component basically at the same time and evenly, which is beneficial for multiple second flow channels 412 to simultaneously introduce the third component into the spinneret hole, further ensuring the stable and continuous preparation of the composite fiber.

[0082] Figure 5 The structure shown is basically the same Figure 4 The only difference is that the second flow channels 412 are arranged separately from each other and cannot be gathered in the middle. Specifically, the middle is made solid and arranged in a solid middle 419, so that the preparation of hollow composite fibers can be achieved.

[0083] Figure 6 and Figure 7 The internal flow channel of the distribution plate 41 is revealed by cutting open a portion of the distribution plate 41. Figure 8 and Fig. 9The internal flow channels of the spinneret assembly 40 including the distribution plate 41 and the spinneret are revealed by partially cutting open; specifically, the first component and the second component introduced from the first component introduction slot and the second component introduction slot respectively pass into the first flow channel 411 through the fifth flow channel 415, the outlet of the first flow channel 411 is opposite to the inlet of the spinneret hole 421, the third component introduced from the third component introduction slot flows in sequence through the first sub-flow channel 4141 and the second sub-flow channel 4142 of the fourth flow channel and enters the third flow channel 413, wherein the axis line of the first sub-flow channel 4141, the axis line of the fifth flow channel 415 and the axis line of the first flow channel 411 are all parallel, the second sub-flow channel 4142 is connected to the third flow channel 413 and its outlet is staggered from the inlet of the second flow channel 412, the third flow channel 413 evenly distributes the third component to multiple second flow channels 412 at the same time, and the third component can quickly fill the second flow channels 41 2, and enters the spinneret hole 421 through the lower opening of the second flow channel 412, the orthographic projections of the first flow channel 411 and the second flow channel 412 are both located within the orthographic projection range of the entrance of the spinneret hole 421, and the axis of the first flow channel 411 is perpendicular to the axis of the second flow channel 412; here, the present invention designs the structure of the first flow channel 411 and the second flow channel 412, and the purpose of the design is to enable the first component, the second component and the third component to be in a suitable pressure state and flow state when they are distributed and introduced, further, the area of ​​the cross section of the first flow channel 411 perpendicular to the length direction is S1, the cross section of the first flow channel 411 perpendicular to the length direction can be circular, the area of ​​the cross section of the second flow channel 412 perpendicular to the length direction is S2, the cross section of the second flow channel 412 perpendicular to the length direction is square, and at the same time, they each meet the following conditions (see further Fig.10 ): The length of the first flow channel 411 is recorded as L1, and satisfies the following condition: S1 = π × (L1 / 2a) 2 , and 5≤a≤20; the length of the second flow channel 412 is recorded as L2, and satisfies the following condition: S2=π×(L2 / 2b) 2 , and 1≤b≤10; further preferably, L1, L2, S1, S2 can satisfy the following conditions:

[0084] And 1.5≤c≤5;

[0085] The first flow channel 411 and the second flow channel 412 are the last distribution parts of the distribution plate 41, and the subsequent three components will enter the spinneret and be ejected through the spinneret. The present invention has experimentally found that by limiting the structure of the first flow channel 411 and the second flow channel 412 as mentioned above, it can better ensure that the three components have a suitable pressure state and flow state when being distributed, thereby stably and continuously preparing composite fibers, reducing or even avoiding the uneven distribution caused by the interaction between the components and the possible leakage of slurry.

[0086] In addition, the outlets of the plurality of first flow channels 411 are respectively distributed on the circumference of the first circle, and the inlets of the plurality of second flow channels 412 are respectively distributed on the circumference of the second circle; the center of the first circle coincides with the center of the second circle or the straight line where the two centers are located is parallel to the axis of the first flow channel 411. Further, the diameter of the first circle is 1 / 3-3 / 4 of the diameter of the second circle, and in the embodiment of the present invention, about 1 / 2 can be used, and a fan-shaped area is formed between two adjacent second flow channels 412, and the first flow channel 411 is located at the centroid of the fan-shaped area, and the cross section of the spinneret hole 421 perpendicular to the length direction is circular.

[0087] See also Fig.11 As shown, it is another schematic diagram of the feeding structure of the three components of the present invention. Figure 2 In terms of the above, another composite fiber structure will be obtained; of course, the difference is basically that the arrangement of the first component and the second component is different, and the subsequent spinneret structure is the same. Figure 2 The feed structure shown will give Fig.13 or Fig.15 The structure of the left-right arrangement shown, Fig.11 The feed structure shown will give Fig.12 or Fig.14 The structure of the up-and-down arrangement (inside-outside arrangement) shown in FIG. Fig.11 The fourth flow channel 414' is located at the same Figure 2 The first component introduction groove 416' and the second component introduction groove 417' are arranged opposite to each other, and the fifth flow channel 415' is located in the middle of the first component introduction groove 416' and the second component introduction groove 417'. In particular, only one second component introduction groove 417' is arranged, which corresponds to multiple first component introduction grooves 416'. Such a feeding form is conducive to forming Fig.12 or Fig.14 The first component and the second component are shown in an up-and-down arrangement.

[0088] The cross-sectional schematic diagram of the composite fiber, elastic shaped fiber and the single component fiber formed by the third component of the present invention is shown in Figures 12 to 15 As shown;

[0089] in, Fig.12and Fig.13 In the embodiment, the composite fiber 50 is generally circular in cross section, the single component region 51 is composed of the third component 30, and the double component region 52 is composed of the first component 10 and the second component 20; the third component 30 forms a single component fiber 70, specifically a "M"-shaped fiber, which has a very large specific surface area, and the elastic special-shaped fiber 60 composed of the first component 10 and the second component 20 is Fig.12 and Fig.13 Specifically, the distribution modes of the first component 10 and the second component 20 are different, and these distribution modes can be achieved by adjusting the feeding direction of the first component 10 and the second component 20 introduced on the distribution plate ( Fig.12 Can be used Fig.11 The three-component feeding direction is shown. Fig.13 Can be used Figure 2 The elastic shaped fiber 60 composed of the first component 10 and the second component 20 has been tested and its strength, such as tear strength and glossiness, has shown relatively excellent performance;

[0090] Fig.14 and Fig.15 In the embodiment, the composite fiber 50 is a hollow composite fiber as a whole, and its cross section has a hollow structure 53, and the hollow structure 53 can be passed through Figure 5 The distribution plate structure shown in the figure is realized, and the structure of the elastic shaped fiber 60 made in this way is similar to Fig.12 , Fig.13 There are some differences in the two, but after testing, the two have basically the same performance, but one is a hollow structure and the other is a solid structure, so there will be differences in the degree of force when peeling and disassembling; at the same time, the single-component fiber obtained after mechanical peeling and disassembly of the hollow composite fiber is presented in multiple "straight" shapes, which has a unique touch and gloss, and is mainly used in sun-proof skin clothing, etc. In addition, the hollow composite fiber can be used for high-end skin clothing, down jackets, etc.

[0091] The composite fiber prepared by the invention has a linear density of 20-200 dtex, a breaking elongation of 10%-30%, a breaking strength of 2.6-3.5 cN / dtex, a dyeing uniformity greater than or equal to level 4.5, a boiling water shrinkage of 6%-12%, and a curling shrinkage of 20%-40%.

[0092] The above scheme is further described below in conjunction with specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions adopted in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0093] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0094] Embodiment 1:

[0095] This example provides a composite fiber, an elastic shaped fiber and a method for preparing the same, using a spinneret of the structure shown in the figure above according to the FDY process, especially using Fig.11 The feeding direction of the three components shown in the figure is as follows: low-viscosity PET (intrinsic viscosity is 0.58 dL / g) is used as the first component, high-viscosity PTT (intrinsic viscosity is 1.2 dL / g) is used as the second component, and PA6 (purchased from Wuxi Changan Polymer, brand 1600-1, relative viscosity 2.7) is used as the third component; the feed mass ratio of the first component to the second component is 50:50; the total feed mass ratio of the first component to the second component and the feed mass ratio of the third component is 80:20; in the first flow channel, a=5; in the second flow channel, b=1; After melt metering, each component is introduced into the above-mentioned spinneret assembly and then ejected. The parameters of the FDY process are: the box spinning temperature of the first component is 268°C, the box spinning temperature of the second component is 258°C, the box spinning temperature of the third component is 265°C, the cooling temperature is 23°C, the cooling air pressure is 20Pa, the network pressure is 0.3MPa, the speed of one roller is 1750m / min, the temperature of one roller is 80°C, the speed of the second roller is 3920m / min, the temperature of the second roller is 120°C, and the winding speed is 3800m / min to obtain a composite fiber.

[0096] The composite fiber forms Fig.12 The structure shown has a linear density of 33 dtex, an elongation at break of 25%, and a breaking strength of 3.05 cN / dtex.

[0097] The composite fiber was stripped in a sodium hydroxide aqueous solution (solution concentration of about 2%, temperature of about 100°C, retention time of about 20 minutes) to obtain elastic shaped fibers and "M-shaped" fibers. The performance test results of the elastic shaped fibers are shown in Table 1.

[0098] Embodiment 2:

[0099] This example provides a composite fiber, an elastic shaped fiber and a method for preparing the same, using a spinneret of the structure shown in the figure above according to the FDY process, especially using Figure 2The feeding direction of the three components shown in the figure is as follows: low-viscosity PET (intrinsic viscosity is 0.58 dL / g) is used as the first component, high-viscosity PBT (intrinsic viscosity is 1.28 dL / g) is used as the second component, and PA6 (purchased from Wuxi Changan Polymer, brand 1600-1, relative viscosity 2.7) is used as the third component; the feed mass ratio of the first component to the second component is 50:50; the total feed mass ratio of the first component to the second component and the feed mass ratio of the third component is 80:20; in the first flow channel, a=12; in the second flow channel, b=7; After the components are melted and measured, they are passed into the above-mentioned spinneret assembly and then sprayed out. The parameters of the FDY process are: the box spinning temperature of the first component is 266°C, the box spinning temperature of the second component is 260°C, the box spinning temperature of the third component is 264°C, the cooling temperature is 23°C, the cooling air pressure is 25Pa, the network pressure is 0.35MPa, the speed of one roller is 1820m / min, the temperature of one roller is 82°C, the speed of the second roller is 4080m / min, the temperature of the second roller is 125°C, and the winding speed is 4000m / min to obtain a composite fiber.

[0100] The composite fiber forms Fig.13 The structure shown has a linear density of 55 dtex, an elongation at break of 25%, and a breaking strength of 3.15 cN / dtex.

[0101] The composite fiber was stripped in a sodium hydroxide aqueous solution (solution concentration of about 2%, temperature of 100°C, dwelling time of about 20 minutes) to obtain elastic shaped fibers and "M-shaped" fibers. The performance test results of the elastic shaped fibers are shown in Table 1.

[0102] Embodiment 3:

[0103] This example provides a composite fiber, an elastic shaped fiber and a method for preparing the same, using a spinneret of the structure shown in the figure above according to the FDY process, especially using Fig.11The feeding direction of the three components shown in the figure is as follows: low-viscosity PET (with a characteristic viscosity of 0.58 dL / g) is used as the first component, high-viscosity PBT (with a characteristic viscosity of 1.28 dL / g) is used as the second component, and COPET (with a characteristic viscosity of 0.64 dL / g) is used as the third component; the feed mass ratio of the first component to the second component is 50:50; the total feed mass ratio of the first component to the second component and the feed mass ratio of the third component is 75:25; in the first flow channel, a=15; in the second flow channel, b=8; the components are melted After melt metering, it is passed into the above-mentioned spinneret assembly and then ejected. The parameters of the FDY process are: the box spinning temperature of the first component is 268°C, the box spinning temperature of the second component is 262°C, the box spinning temperature of the third component is 272°C, the cooling temperature is 23°C, the cooling wind pressure is 28Pa, the network pressure is 0.3MPa, the speed of one roller is 1750m / min, the temperature of one roller is 85°C, the speed of the second roller is 4065m / min, the temperature of the second roller is 125°C, the winding speed is 4000m / min, and the composite fiber is obtained.

[0104] The composite fiber forms Fig.14 The structure shown has a linear density of 83 dtex, an elongation at break of 21%, and a breaking strength of 2.7 cN / dtex.

[0105] The composite fiber was subjected to alkaline hydrolysis (alkaline hydrolysis using sodium hydroxide aqueous solution, concentration of about 2.5%, temperature of 100°C, retention time of about 25 minutes), COPET was dissolved to obtain elastic shaped fiber. The performance test results of the elastic shaped fiber are shown in Table 1.

[0106] Embodiment 4:

[0107] This example provides a composite fiber, an elastic shaped fiber and a method for preparing the same, using a spinneret of the structure shown in the figure above according to the FDY process, especially using Figure 2The feeding direction of the three components shown in the figure is as follows: low-viscosity PET (intrinsic viscosity is 0.58 dL / g) is used as the first component, high-viscosity PBT (intrinsic viscosity is 1.28 dL / g) is used as the second component, and PA6 (purchased from Wuxi Changan Polymer, brand 1600-1, relative viscosity 2.7) is used as the third component; the feed mass ratio of the first component to the second component is 60:40; the total feed mass ratio of the first component to the second component and the feed mass ratio of the third component is 80:20; in the first flow channel, a=20; in the second flow channel, b=10 ; After the components are melted and measured, they are introduced into the above-mentioned spinneret assembly and then ejected. The parameters of the FDY process are: the box spinning temperature of the first component is 266°C, the box spinning temperature of the second component is 262°C, the box spinning temperature of the third component is 258°C, the cooling temperature is 20°C, the cooling air pressure is 35Pa, the network pressure is 0.3MPa, the speed of one roller is 1950m / min, the temperature of one roller is 88°C, the speed of the second roller is 4260m / min, the temperature of the second roller is 135°C, and the winding speed is 4200m / min to obtain a composite fiber.

[0108] The composite fiber forms Fig.15 The structure shown has a linear density of 110 dtex, an elongation at break of 22%, and a breaking strength of 3.2 cN / dtex.

[0109] The composite fiber was stripped in a sodium hydroxide solution (solution concentration 2%, temperature 100°C, dwell time 25 min) to obtain elastic shaped fibers and "straight" shaped fibers. The performance test of the elastic shaped fibers is shown in Table 1.

[0110] Comparative Example 1:

[0111] The design is basically the same as Example 1, except that in the first flow channel, a=30, and in the second flow channel, b=15. After trying this design in practice, it was found that the spinning assembly had a filament sticking to the plate, and spinning could not proceed normally.

[0112] Comparative Example 2:

[0113] The design is basically the same as Example 1, except that a=1 in the first flow channel and b=0.5 in the second flow channel. After trying the design in practice, it was found that the wire could not be normally produced, the wire was not continuous, and the wire was intermittent.

[0114] Performance Test:

[0115] The composite fibers obtained in the above-mentioned Examples 1-4 were subjected to the following performance tests, wherein the following test items were used: (1) the linear density was determined by referring to GB / T 14343-2008; (2) the elongation at break was determined by referring to GB / T 14344-2008; (3) the breaking strength was determined by referring to GB / T 14344-2008; (4) the dyeing uniformity (Grey level) was determined by referring to GB / T 6508-2015; (5) the boiling water shrinkage was determined by referring to GB / T 6505-2017; (6) the curl shrinkage was determined by referring to GB / T 6506-2017.

[0116] Table 1

[0117]

[0118] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

[0119] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

Claims

1. A method for preparing a composite fiber, characterized in that: The preparation method comprises: The first component, the second component and the third component are used as raw materials, the first component and the second component have different shrinkage rates when solidified, and the third component respectively undergoes phase separation with the first component and the second component when in molten contact; Using a spinneret assembly to spin extrude the composite fiber; The spinneret assembly comprises a distribution plate and a spinneret formed with spinneret holes, the distribution plate comprises a first flow channel for simultaneously introducing the first component and the second component into the spinneret holes, and a second flow channel for introducing the third component into the spinneret holes, and the axis of the first flow channel is perpendicular to the axis of the second flow channel; The area of ​​the cross section of the first flow channel perpendicular to the length direction is S1, the length of the first flow channel is L1, and the following conditions are met: And 5≤a≤20; The area of ​​the cross section of the second flow channel perpendicular to the length direction is S2, the length of the second flow channel is L2, and the following conditions are met: And 1≤b≤10; There are multiple first flow channels and multiple second flow channels respectively, and two adjacent first flow channels are separated by one second flow channel. The multiple second flow channels are separated from each other or their respective axial lines intersect at the same point, and the orthographic projections of the first flow channel and the second flow channel are both located within the orthographic projection range of the entrance of the spinneret.

2. The method for preparing a composite fiber according to claim 1, characterized in that: The outlets of the plurality of first flow channels are respectively distributed on the circumference of a first circle, and the inlets of the plurality of second flow channels are respectively distributed on the circumference of a second circle; The center of the first circle coincides with the center of the second circle, or the straight line where the two centers are located is parallel to the axis of the first flow channel.

3. The method for preparing the composite fiber according to claim 2, characterized in that: The diameter of the first circle is 1 / 3-3 / 4 of the diameter of the second circle.

4. The method for preparing a composite fiber according to claim 1 or 2, characterized in that: The cross-section of the first flow channel perpendicular to the length direction is circular; and / or, the cross-section of the second flow channel perpendicular to the length direction is square; and / or, a fan-shaped area is formed between two adjacent second flow channels, and the first flow channel is located at the centroid of the fan-shaped area; and / or, the cross-section of the spinneret hole perpendicular to the length direction is circular.

5. The method for preparing the composite fiber according to claim 1, characterized in that: The distribution plate further includes a third flow channel, which surrounds the outer periphery of the plurality of second flow channels and is respectively communicated with the plurality of second flow channels.

6. The method for preparing the composite fiber according to claim 5, characterized in that: The distribution plate further includes at least one fourth flow channel and a plurality of fifth flow channels. The at least one fourth flow channel is communicated with the third flow channels respectively, and the fifth flow channels are communicated with the first flow channels in a one-to-one correspondence.

7. The method for preparing the composite fiber according to claim 6, characterized in that: The fourth flow channel includes a first sub-flow channel and a second sub-flow channel which are interconnected, the axis line of the first sub-flow channel, the axis line of the fifth flow channel and the axis line of the first flow channel are all parallel, the second sub-flow channel is connected to the third flow channel and its outlet is staggered with the inlet of the second flow channel.

8. The method for preparing a composite fiber according to claim 1, characterized in that: Make L1, L2, S1, S2 meet the following conditions: And 1.5≤c≤5; And / or, the difference in intrinsic viscosity between the first component and the second component is 0.15-0.7dL / g; and / or, the feed mass ratio of the first component to the second component is 10:90-90:10; and / or, the feed mass ratio of the total feed mass of the first component and the second component to the feed mass ratio of the third component is 90:10-50:

50.

9. The method for preparing a composite fiber according to claim 1, characterized in that: The first component and the second component are independently selected from PET, PBT or PTT, and the third component is PA6, COPET, PE or PP.

10. The method for preparing composite fibers according to claim 1, characterized in that: The preparation method adopts the FDY process, and the parameters of the FDY process are: the box spinning temperature of the first component is 240-295°C, the box spinning temperature of the second component is 240-295°C, the box spinning temperature of the third component is 240-285°C, the cooling temperature is 19-23°C, the cooling wind pressure is 15-35Pa, the network pressure is 0.25-0.4MPa, the speed of one roller is 1600-2800m / min, the temperature of one roller is 60-92°C, the speed of the second roller is 4000-6000m / min, the temperature of the second roller is 95-155°C, and the winding speed is 3900-5800m / min.

11. A composite fiber produced by the method for producing a composite fiber according to any one of claims 1 to 10.

12. The composite fiber according to claim 11, characterized in that The breaking strength of the composite fiber is greater than or equal to 2.4 cN / dtex.

13. The composite fiber according to claim 11, characterized in that The breaking elongation of the composite fiber is 10%-30%, and the linear density is 20-200 dtex; and / or the dyeing uniformity of the composite fiber is greater than or equal to level 4.5; and / or the boiling water shrinkage of the composite fiber is 6%-12%; and / or the curling shrinkage of the composite fiber is 20%-40%.

14. A composite fiber, characterized in that: The composite fiber comprises a first component, a second component and a third component, the first component and the second component have different shrinkage rates when solidified, and the third component and the first component and the second component respectively undergo phase separation when mixed and melted; The cross section of the composite fiber perpendicular to the length direction includes a plurality of monocomponent regions and bicomponent regions, two adjacent bicomponent regions are separated by one monocomponent region, the monocomponent region occupies at most 50% of the area of ​​the cross section perpendicular to the length direction, and the plurality of monocomponent regions are separated from each other or connected to each other at the center of the cross section perpendicular to the length direction; The single-component region includes the third component, and the dual-component region includes the first component and the second component. The first component and the second component are arranged in parallel, and both the first component and the second component are in contact with the third component.

15. The composite fiber according to claim 14, characterized in that The two-component area is a fan-shaped structure.

16. The composite fiber according to claim 14, characterized in that The cross section perpendicular to the length direction has a hollow structure, and the two-component area is a remaining structure after removing a part adjacent to the center of the fan-shaped structure.

17. The composite fiber according to claim 14, characterized in that In the two-component region, the portion where the first component contacts the second component is in an arc shape.

18. An elastic shaped fiber, characterized in that: The elastic shaped fiber is obtained by removing the third component from the composite fiber described in any one of claims 11 to 17.

19. The elastic shaped fiber according to claim 18, characterized in that: The removal method includes mechanical stripping, alkaline solution stripping or dissolution removal.

20. A textile, characterized in that: At least a part of the composite fiber is composed of the composite fiber according to any one of claims 11 to 17 or the elastic shaped fiber according to any one of claims 18 to 19.

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