Low-strength polyester fully drawn yarn as well as preparation method and application thereof

Abstract

The invention discloses a low-strength polyester fully-drawn yarn and a preparation method and application thereof.The preparation method comprises the steps that a polyester melt is sprayed out of a yarn strip through a spinneret orifice with a flat cross section, the yarn strip is cooled and oiled, then the yarn strip makes frictional contact with a brittle damage part with a rough surface layer, the yarn strip enters a pre-interlacer to be treated, drawn and shaped, and the low-strength polyester fully-drawn yarn is obtained. The main network is interlaced; wherein the surface roughness Ra of the rough surface layer is 0.5-1.5, filaments located between the brittle damage part and the pre-interlacing device enter the pre-interlacing device at an included angle alpha, the acute included angle between the filaments entering the pre-interlacing device and the perpendicular normal of the end face, where the filaments enter, of the pre-interlacing device is the included angle alpha, and the included angle alpha is 10-30 degrees; according to the method, the ideal brittle damage effect of the polyester filaments can be achieved without being subjected to multiple treatments such as a high-temperature environment, strong alkali and alcohol, the energy consumption and the cost are low, and the prepared cloth has low tearing strength and is suitable for preparing medical adhesive tape, wiring harness adhesive tape or trademark cloth.

Description

Technical Field

[0001] The invention relates to the field of functional yarns, in particular to a low-strength cationic dye-dyable polyester fully-drawn yarn, and specifically to a low-strength polyester fully-drawn yarn and a preparation method and application thereof. Background Art

[0002] The base fabrics of products such as medical tapes, wiring harness tapes, and trademark cloths generally require lower tear strength so that consumers can easily tear them during use. However, the tear strength of base fabrics made of conventional synthetic fibers basically cannot meet the requirements. Therefore, the commonly used materials at present are mainly cloth woven from acetate fibers. However, the source of acetate fibers is limited, the cost is relatively high, and it is not easy to dye. Based on the above problems, patent CN110846779B discloses a method for manufacturing polyester tearable cloth. The patent uses a strong alkali for treatment. The strong alkali contains sodium hydroxide and amines at the same time. The amount of amine is 5-50g / L, the amount of sodium hydroxide is 5-50g / L, and the treatment is carried out 6 times at 130°C; patent CN110846778A discloses a method for producing nylon-polyester tearable cloth. The patent uses a strong alkali and alcohol for alternating treatment. The alkali is sodium hydroxide or sodium carbonate, and the alcohol is such as ethylene glycol, benzyl alcohol, etc. The amount of alkali is 5-50g / L, and the alcohol is The dosage is 5-50g / L, and the treatment is carried out 6 times at 130°C; however, although the treatment methods of the two patents both claim to achieve a reduction in tear strength and can be made into easy-to-tear cloth, on the one hand, they use a large amount of strong alkali, amine substances, and alcohol substances, which will inevitably produce a large amount of alkaline wastewater, which is difficult to post-treat, requires a large amount of resources for wastewater treatment, is costly, and is not environmentally friendly. On the other hand, they need to be treated 6 times at conditions as high as 130°C, which has high energy consumption, and high-temperature treatment is not conducive to safe production. In addition, more processes are added, and the procedures are cumbersome. Summary of the invention

[0003] The purpose of the present invention is to overcome one or more deficiencies in the prior art and to provide a novel method for preparing low-strength polyester fully-drawn yarn for "easy-to-tear cloth" which has low strength, bright luster, is easy to dye and can be well woven.

[0004] The present invention also provides a low-strength fully-drawn polyester yarn prepared by the above method and application of the yarn in preparing medical tape, wiring harness tape or trademark cloth.

[0005] In order to achieve the above object, a technical solution adopted by the present invention is:

[0006] A method for preparing a low-strength polyester fully drawn yarn, the method comprising:

[0007] The polyester melt is sprayed out into filaments through a spinneret with a flat cross section. After cooling and oiling, the filaments are brought into friction contact with fragile parts with a rough surface layer, and then enter the pre-netting device for processing, stretching and shaping, and the main netting is netted and entangled.

[0008] Among them, the surface roughness Ra of the rough surface layer is 0.5-1.5, the wire strip located between the fragile part and the pre-network device enters the pre-network device at an angle α, and the acute angle between the wire strip entering the pre-network device and the vertical normal of the end face of the pre-network device for the wire strip to enter is the angle α, and the angle α is 10°-30°.

[0009] According to some preferred aspects of the present invention, the aspect ratio of the spinneret hole having a flat cross section is greater than or equal to 5.

[0010] According to some preferred aspects of the present invention, the polyester melt is obtained by melting a polyester raw material, and the intrinsic viscosity of the polyester raw material is less than or equal to 0.58 dL / g.

[0011] Furthermore, the aspect ratio of the spinneret hole with a flat cross section is 5-8, for example, it can be 5, 5.5, 6, 6.5, 7, 7.5, 8, etc.

[0012] Furthermore, the polyester melt is obtained by melting a polyester raw material, and the intrinsic viscosity of the polyester raw material is 0.52-0.57 dL / g, for example, 0.52 dL / g, 0.53 dL / g, 0.54 dL / g, 0.55 dL / g, 0.56 dL / g, 0.57 dL / g, etc.

[0013] Furthermore, the polyester melt is a cationic dyeable polyester melt. According to a specific aspect of the present invention, the polyester melt is a cationic dyeable polyester melt, which is obtained by introducing dimethyl isophthalate with a polar sodium sulfonate group into polyester chips, which can be commercially obtained or prepared according to conventional methods in the art, and will not be described in detail here.

[0014] According to some preferred aspects of the present invention, the surface roughness Ra of the rough surface layer is 0.7-1.1, for example, it can be 0.7, 0.72, 0.75, 0.78, 0.80, 0.83, 0.85, 0.88, 0.9, 0.92, 0.95, 0.96, 0.98, 1.0, 1.05, 1.08, 1.1, etc.

[0015] According to some preferred aspects of the present invention, the angle α is 15°-25°, for example, it can be 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, etc.

[0016] In some preferred embodiments of the present invention, the fragile part includes a mounting portion and a fragile portion arranged on the mounting portion, the rough surface layer is formed on the surface of the fragile portion, the fragile portion includes a wire hole allowing the wire to pass through and a clearance gap allowing the wire to freely enter and exit, and the wire hole is connected to the clearance gap.

[0017] According to some preferred aspects of the present invention, the rough surface layer has at least two locations in contact with the filaments.

[0018] According to some preferred aspects of the present invention, the wire strip enters from a lower portion of a rear portion of the wire hole and extends out from an upper portion of a front portion of the wire hole.

[0019] According to some preferred aspects of the present invention, the fragile part is made of ceramic.

[0020] In some preferred embodiments of the present invention, the method for preparing the low-strength polyester fully stretched yarn includes: transporting the polyester melt through a melt pipe, passing through a melt booster pump, a melt cooler, and a spinning box, and then ejecting it from a spinneret hole with a flat cross-section, being kept warm in a windless insulation zone, being cooled in a ring-blown cooling zone, being oiled by an oiling nozzle, making brittle damaged yarns with a rough surface layer, pre-networking and oiling, stretching and shaping by a first hot roller and a second hot roller, interlacing the main network, and winding and forming by a winding machine.

[0021] Furthermore, the process parameters for preparing the low-strength polyester fully-drawn yarn are controlled as follows: the pump pressure after the booster pump is 16-20 MPa, the outlet temperature of the melt cooler is 274-277°C, the temperature of the spinning box is 280-285°C, the height of the windless insulation zone is 50-75 mm, the speed of the first hot roller is 1800-3500 m / min, the temperature of the first hot roller is 60-90°C, the speed of the second hot roller is 4000-5100 m / min, the temperature of the second hot roller is 80-130°C, and the winding speed is 4000-5000 m / min.

[0022] Another technical solution provided by the present invention is: a low-strength polyester fully-stretched yarn made by the preparation method of the low-strength polyester fully-stretched yarn described above, wherein the breaking strength of the low-strength polyester fully-stretched yarn is less than or equal to 2.2 cN / dtex.

[0023] In some preferred embodiments of the present invention, the breaking strength of the low-strength polyester fully drawn yarn is 1.8-2.2 cN / dtex, and the breaking elongation is 20% to 30%.

[0024] In some preferred embodiments of the present invention, the single yarn fineness of the low-strength polyester fully-drawn yarn is 0.5-3.7 dtex.

[0025] Another technical solution provided by the present invention is: use of the low-strength fully-drawn polyester yarn described above in the preparation of medical tapes, wiring harness tapes or trademark cloths.

[0026] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0027] Based on the defects of the existing preparation of medical tapes, harness tapes, and easy-tear cloths for trademark cloth, such as limited raw material sources, high costs, or the need for multiple treatments using high temperature environments, strong alkalis, alcohols, etc., the present invention innovatively provides a new preparation process. The preparation process is based on the FDY process, and uses a spinneret with a flat cross-section to spray the polyester melt, which can make the primary fiber have a large degree of irregularity. The special fiber cross-section can cause the yarn to easily produce stress concentration and break when subjected to external force. When a fragile part with a rough surface layer is introduced after oiling to treat the oiled silk strips, the rough surface The surface can not only produce frictional brittle damage to the oiled silk strips, but also will not cause excessive damage to the silk strips due to the presence of oil, resulting in obvious burrs and hairy silk. The rough surface can also cause the silk strips to vibrate slightly during the friction process, which plays a certain role in promoting the transfer, penetration and dispersion of oil into the interior of the silk strips, and makes the spinning oil evenly distributed on the surface of each single fiber, so that the single fiber has better bundling, and the silk strips run more stably during spinning. When the silk strips located between the brittle parts and the pre-network device are further controlled to enter the pre-network device at an angle α, the brittle damage effect of the rough surface on the silk strips can be fully utilized and adjusted.

[0028] The above method of the present invention can not only achieve the ideal brittle effect of polyester filaments without the need for multiple treatments such as high temperature environment, strong alkali, alcohol, etc., and the prepared cloth has lower tear strength, but also only needs to embed the processing process into the conventional FDY process, which greatly shortens the process, reduces costs, saves energy, and does not produce additional strong alkali, alcohol wastewater, etc., which is beneficial to environmental protection and the implementation of large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0030] Figure 1 It is a schematic structural diagram of a production device used in the method for preparing low-strength polyester fully drawn yarn in an embodiment of the present invention;

[0031] Figure 2It is a schematic diagram of the angle of the brittle component guiding the yarn in the method for preparing the low-strength polyester fully drawn yarn in an embodiment of the present invention;

[0032] Figure 3 It is a schematic diagram of the structure of a fragile part in an embodiment of the present invention;

[0033] Figure 4 This is one of the structural schematic diagrams of the spinneret hole with a flat cross section according to the present invention;

[0034] Figure 5 for Figure 4 Schematic diagram of the cross section of the polyester fiber ejected from the spinneret shown;

[0035] Figure 6 The second structural schematic diagram of the spinneret hole with a flat cross section of the present invention;

[0036] Figure 7 for Figure 6 Schematic diagram of the cross section of the polyester fiber ejected from the spinneret shown;

[0037] In the accompanying drawings, the following are marked: 1. melt booster pump; 2. melt cooler; 3. spinning box; 4. annular air cooling zone; 5. oiling nozzle; 6. wire guide hook; 7. fragile part; 71. mounting portion; 72. fragile portion; 721. wire hole; 722. clearance; 73. rough surface layer; 8. pre-network device; 9. U-shaped porcelain part; 10. first hot roller; 11. second hot roller; 12. main network device; 13. winder; 14. spinneret hole; 15. wire strip; 16. polyester fiber. DETAILED DESCRIPTION

[0038] The present invention provides a polyester product with required mechanical properties such as low tear strength and a preparation method thereof, so as to overcome the defects of the prior art of using a high temperature environment, a strong alkali, alcohols and the like for multiple treatments.

[0039] A method for preparing low-strength polyester fully drawn yarn, the preparation method comprising: using a spinneret with a flat cross-section to spray polyester melt into yarn, cooling, oiling, and then frictionally contacting with a fragile part with a rough surface layer, and then entering a pre-network device for processing, stretching and shaping, and main network interlacing; wherein the surface roughness Ra of the rough surface layer is 0.5-1.5, the yarn located between the fragile part and the pre-network device enters the pre-network device at an angle α, and the acute angle between the yarn entering the pre-network device and the vertical normal of the end face of the pre-network device for the yarn to enter is the angle α, and the angle α is 10°-30°.

[0040] Further, in some implementation cases, the present invention uses cationic dye-dyable polyester melt with low characteristic viscosity as raw material, and sprays it with a specially constructed wavy flat or flat spinneret hole. The special aspect ratio of the spinneret hole will cause the primary fiber to have a large profile, thereby obtaining a special fiber cross-section and causing the yarn to easily produce stress concentration and break when subjected to external force. At the same time, after the precursor is formed, a component that can make the precursor brittle is added before the pre-network oil mixing, and a reasonable angle is matched to further damage the precursor without generating mechanical hair. It is guaranteed that the silk strip can be damaged, and stable production and package forming can be guaranteed. Therefore, the base fabric produced by using this low-intensity cationic dye-dyable polyester fully drawn yarn has the advantages of achieving lower tear strength without multiple brittle damage treatments such as high temperature environment, strong alkali, alcohols, etc., and has the advantages of reducing the process, reducing costs, and reducing energy consumption.

[0041] Combine the following Figures 1 to 7 Preferred embodiments of the present invention are described in detail.

[0042] See also Figures 1 to 4 and Figure 6 The present invention provides a production system for low-strength polyester fully drawn yarn, which includes a spinneret for ejecting polyester melt, a windless heat preservation zone, a ring-blowing cooling zone 4, an oiling nozzle 5, a wire guide hook 6, a fragile part 7, a pre-network device 8, a wire guide, a first hot roller 10, a second hot roller 11, a main network device 12 and a winder 13, which are arranged in sequence. A spinneret hole 14 is formed on the spinneret, and the fragile part 7 has a rough surface layer 73 that can be in frictional contact with the filament 15, and the cross-section of the spinneret hole 14 is flat.

[0043] Furthermore, the production system also includes a melt booster pump 1, a melt cooler 2, and a spinning manifold 3 which are arranged in sequence, and a spinneret is arranged in the spinning manifold 3.

[0044] Furthermore, the fragile part 7 includes a mounting portion 71, a fragile part 72 formed on the mounting portion 71, a rough surface layer 73 formed on the surface of the fragile part 72, the mounting portion 71 is used to mount and fix the entire fragile part 7 on a certain supporting component, the fragile part 72 includes a wire hole 721 allowing the wire 15 to pass through and a clearance gap 722 allowing the wire to freely enter and exit, and the wire hole 721 is connected to the clearance gap 722; the mounting portion 71 and the fragile part 72 can be integrally formed to form the fragile part 7, and the material of the fragile part 7 can be ceramic, The damaging part 7 can make the wire strip 15 leaving the wire hole 721 extend along the first direction, and the vertical normal of the end face of the pre-network device 8 for the wire strip 15 to enter extends along the second direction. The first direction intersects with the second direction, and the two directions intersect to form an angle of 10°-30°, which can further be 15°-25°, that is, the wire strip located between the brittle damaging part 7 and the pre-network device 8 enters the pre-network device 8 at an angle α, and the acute angle between the wire strip entering the pre-network device 8 and the vertical normal of the end face of the pre-network device 8 for the wire strip to enter is the above-mentioned angle α.

[0045] Furthermore, the surface roughness Ra of the rough surface layer 73 is 0.5-1.5, preferably 0.7-1.1. The appropriate roughness is more conducive to damaging the filaments without causing excessive brittleness; the length-to-width ratio of the spinneret hole 14 with a flat cross section is greater than or equal to 5 (length is L, width is W, that is, L / W≥5), preferably, the length-to-width ratio is 5-8.

[0046] Furthermore, the yarn guide is a U-shaped ceramic part 9, and the polyester melt adopts a cationic dyeable polyester melt with a characteristic viscosity of 0.52-0.57 dL / g.

[0047] See also Figure 4 As shown, it exemplarily shows a schematic diagram of the structure of a spinneret hole 14 with a flat cross section, the cross section is roughly wavy, and the cross section of the ejected polyester fiber 16 is also roughly wavy and flat, for example, see Figure 5 As shown, of course, since the polyester melt is not completely regular after being ejected, the cross-section of the obtained fiber filaments presents some slight differences at each wave. This type of polyester fiber 16 has more groove structures, a larger fiber specific surface area, and will have better moisture absorption and perspiration and breathability.

[0048] See also Figure 6 As shown, it exemplarily shows a schematic diagram of the structure of a spinneret hole 14 with a flat cross section. The cross section is roughly long and flat, and the cross section of the ejected polyester fiber 16 is also roughly long and flat. For example, see Figure 7 As shown, of course, since the polyester melt is not completely regular after being ejected, the cross-sectional profile of the obtained fiber filaments presents some slight differences and does not extend completely linearly, but has some slight convexities and ups and downs.

[0049] The polyester fiber 16 has a large degree of irregularity, and the special fiber cross-section can cause the yarn to easily generate stress concentration and break when subjected to external force, thereby reducing the fiber's breaking strength and facilitating the preparation of a cloth with low tear strength.

[0050] During the working process, the polyester melt is transported through the melt pipeline, passes through the melt booster pump 1, the melt cooler 2, and the spinning box 3, and then ejected from the spinneret 14 with a flat cross-section, is kept warm in the windless insulation zone (not shown), cooled in the annular blowing cooling zone 4, oiled by the oiling nozzle 5, the fragile parts 7 with a rough surface layer 73 are brittlely damaged The filaments are evenly oiled by the pre-networking device 8, stretched and shaped by the first hot roller 10 and the second hot roller 11, the main network device 12 is networked and intertwined, and the winder 13 is wound and formed. Among them, the pump pressure after the melt booster pump 1 is 16-20MPa, the outlet temperature of the melt cooler 2 is 274-277℃, the temperature of the spinning box 3 is 280-285℃, the height of the windless insulation zone is 50-75mm, the speed of the first hot roller 10 is 1800-3500m / min, the temperature of the first hot roller 10 is 60-90℃, the speed of the second hot roller 11 is 4000-5100m / min, the temperature of the second hot roller 11 is 80-130℃, and the winding speed of the winder 13 is 4000-5000m / min.

[0051] 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.

[0052] Unless otherwise specified in the following examples, all raw materials are commercially available.

[0053] Example 1

[0054] This example provides a method for preparing a low-strength polyester fully drawn yarn, using the above Figures 1 to 4 The production system of the structure shown in the figure, the specific preparation method includes:

[0055] The cationic dyeable polyester melt with an intrinsic viscosity of 0.53 dL / g is transported through a melt pipeline, passes through a melt booster pump, a melt cooler, a spinning box, and then from Figure 4The yarn is ejected from a spinneret with a roughly wavy and flat cross-section (the length-to-width ratio of the spinneret is 5.5), and is kept in a windless insulation zone, cooled in a ring-blown cooling zone, oiled by an oiling nozzle, the brittle and damaged yarns are treated with a pre-networking device, stretched and shaped by the first and second hot rollers, interwoven by the main network device, and wound on a winder to produce 83dtex / 36f wavy and flat low-strength polyester fully-drawn yarn.

[0056] Among them, the preparation process parameters of low-strength polyester fully drawn yarn are: the pump pressure after the melt booster pump is 18MPa, the outlet temperature of the melt cooler is 275°C, the temperature of the spinning box is 282°C, the height of the windless insulation zone is 75mm, the cooling temperature of the annular air cooling zone is 20°C, the oiling rate is 0.95%, the angle α is 18°, and the surface roughness Ra of the rough surface layer is 0.88; the speed of the first hot roller is 3025m / min, the temperature of the first hot roller is 68°C, the speed of the second hot roller is 4457m / min, the temperature of the second hot roller is 115°C, and the winding speed is 4400m / min.

[0057] The physical properties of the prepared 83dtex / 36f wavy flat low-strength polyester fully drawn yarn are as follows: fineness (test standard: GB / T 8960-2015, the same below) 83.2dtex, breaking strength (test standard: GB / T 8960-2015, the same below) 1.95cN / dtex, breaking elongation (test standard: GB / T 8960-2015, the same below) 23.4%, boiling water shrinkage (test standard: GB / T 8960-2015, the same below) 7.4%, network degree (test standard: GB / T 8960-2015, the same below) 9 pieces / m.

[0058] Example 2

[0059] This example provides a method for preparing a low-strength polyester fully drawn yarn, using the above Figures 1 to 3 , Figure 6 The production system of the structure shown in the figure, the specific preparation method includes:

[0060] The cationic dyeable polyester melt with an intrinsic viscosity of 0.53 dL / g is transported through a melt pipeline, passes through a melt booster pump, a melt cooler, a spinning box, and then from Figure 6 The yarn is ejected from a spinneret with a roughly flat cross-section (the length-to-width ratio of the spinneret is 6.0), and is kept warm in a windless insulation zone, cooled in a ring-blown cooling zone, oiled by an oiling nozzle, the brittle and damaged yarns are treated with a pre-networking device, stretched and shaped by the first and second hot rollers, interwoven by the main network device, and wound on a winder to produce 83dtex / 36f flat, low-strength polyester fully-drawn yarn.

[0061] Among them, the preparation process parameters of low-strength polyester fully drawn yarn are: the pump pressure after the melt booster pump is 18MPa, the outlet temperature of the melt cooler is 275°C, the temperature of the spinning box is 282°C, the height of the windless insulation zone is 75mm, the cooling temperature of the annular air cooling zone is 20°C, the oiling rate is 0.95%, the angle α is 18°, and the surface roughness Ra of the rough surface layer is 0.88; the speed of the first hot roller is 3025m / min, the temperature of the first hot roller is 68°C, the speed of the second hot roller is 4457m / min, the temperature of the second hot roller is 115°C, and the winding speed is 4400m / min.

[0062] The physical properties of the prepared 83dtex / 36f flat low-strength polyester fully drawn yarn are: fineness 82.7dtex, breaking strength 1.91cN / dtex, breaking elongation 22.1%, boiling water shrinkage 7.6%, and network density 10.5 pieces / m.

[0063] Example 3

[0064] This example provides a method for preparing a low-strength polyester fully drawn yarn, using the above Figures 1 to 4 The production system of the structure shown in the figure, the specific preparation method includes:

[0065] The cationic dyeable polyester melt with an intrinsic viscosity of 0.53 dL / g is transported through a melt pipeline, passes through a melt booster pump, a melt cooler, a spinning box, and then from Figure 4 The yarn is ejected from a spinneret with a roughly wavy and flat cross-section (the length-to-width ratio of the spinneret is 6.0), and is kept in a windless insulation zone, cooled in a ring-blown cooling zone, oiled by an oiling nozzle, the brittle and damaged yarns are treated with a pre-networking device, stretched and shaped by the first and second hot rollers, interwoven by the main network device, and wound on a winder to produce 111dtex / 36f wavy and flat low-strength polyester fully-drawn yarn.

[0066] Among them, the preparation process parameters of low-strength polyester fully drawn yarn are: the pump pressure after the melt booster pump is 18MPa, the outlet temperature of the melt cooler is 276°C, the temperature of the spinning box is 282°C, the height of the windless insulation zone is 75mm, the cooling temperature of the annular air cooling zone is 20°C, the oiling rate is 0.95%, the angle α is 21°, the surface roughness Ra of the rough surface layer is 0.88; the speed of the first hot roller is 2885m / min, the temperature of the first hot roller is 73°C, the speed of the second hot roller is 4675m / min, the temperature of the second hot roller is 118°C, and the winding speed is 4600m / min.

[0067] The physical properties of the prepared 111dtex / 36f wavy flat low-strength polyester fully drawn yarn are: fineness 111dtex, breaking strength 1.99cN / dtex, breaking elongation 21.7%, boiling water shrinkage 7.8%, and network density 8.5 pieces / m.

[0068] Example 4

[0069] This example provides a method for preparing a low-strength polyester fully drawn yarn, using the above Figures 1 to 3 , Figure 6 The production system of the structure shown in the figure, the specific preparation method includes:

[0070] The cationic dyeable polyester melt with an intrinsic viscosity of 0.53 dL / g is transported through a melt pipeline, passes through a melt booster pump, a melt cooler, a spinning box, and then from Figure 6 The yarn is ejected from a spinneret with a roughly flat cross-section (the length-to-width ratio of the spinneret is 5.5), and is kept warm in a windless insulation zone, cooled in a ring-blown cooling zone, oiled by an oiling nozzle, the brittle and damaged yarns are treated with a pre-networking device, stretched and shaped by the first and second hot rollers, interwoven by the main network device, and wound on a winder to produce 111dtex / 36f wavy, flat, low-strength polyester fully-drawn yarn.

[0071] Among them, the preparation process parameters of low-strength polyester fully drawn yarn are: the pump pressure after the melt booster pump is 18MPa, the outlet temperature of the melt cooler is 276°C, the temperature of the spinning box is 283°C, the height of the windless insulation zone is 75mm, the cooling temperature of the annular air cooling zone is 20°C, the oiling rate is 0.95%, the angle α is 21°, and the surface roughness Ra of the rough surface layer is 0.88; the speed of the first hot roller is 2885m / min, the temperature of the first hot roller is 73°C, the speed of the second hot roller is 4675m / min, the temperature of the second hot roller is 118°C, and the winding speed is 4600m / min.

[0072] The physical properties of the prepared 111dtex / 36f wavy flat low-strength polyester fully drawn yarn are: fineness 111dtex, breaking strength 1.93cN / dtex, breaking elongation 20.9%, boiling water shrinkage 6.9%, and network density 9.8 pieces / m.

[0073] Example 5

[0074] This example provides a method for preparing a low-strength polyester fully drawn yarn, using the above Figures 1 to 4 The production system of the structure shown in the figure, the specific preparation method includes:

[0075] The cationic dyeable polyester melt with an intrinsic viscosity of 0.53 dL / g is transported through a melt pipeline, passes through a melt booster pump, a melt cooler, a spinning box, and then from Figure 4 The yarn is ejected from a spinneret with a roughly wavy and flat cross-section (the length-to-width ratio of the spinneret is 6.0), and is kept in a windless insulation zone, cooled in a ring-blown cooling zone, oiled by an oiling nozzle, the brittle and damaged yarns are treated with a pre-networking device, stretched and shaped by the first and second hot rollers, interwoven by the main network device, and wound on a winding machine to produce a 120dtex / 36f wavy and flat low-strength polyester fully-drawn yarn.

[0076] Among them, the preparation process parameters of low-strength polyester fully drawn yarn are: the pump pressure after the melt booster pump is 18MPa, the outlet temperature of the melt cooler is 276°C, the temperature of the spinning box is 283°C, the height of the windless insulation zone is 75mm, the cooling temperature of the annular air cooling zone is 20°C, the oiling rate is 0.95%, the angle α is 23.5°, and the surface roughness Ra of the rough surface layer is 0.88; the speed of the first hot roller is 2805m / min, the temperature of the first hot roller is 74°C, the speed of the second hot roller is 4772m / min, the temperature of the second hot roller is 120°C, and the winding speed is 4700m / min.

[0077] The physical properties of the prepared 120dtex / 36f wavy flat low-strength polyester fully drawn yarn are: fineness 120dtex, breaking strength 1.87cN / dtex, breaking elongation 22.9%, boiling water shrinkage 8.0%, and network density 8.6 pieces / m.

[0078] Example 6

[0079] This example provides a method for preparing a low-strength polyester fully drawn yarn, using the above Figures 1 to 3 , Figure 6 The production system of the structure shown in the figure, the specific preparation method includes:

[0080] The cationic dyeable polyester melt with an intrinsic viscosity of 0.52 to 0.57 dL / g is transported through a melt pipeline, passes through a melt booster pump, a melt cooler, a spinning box, and then from Figure 6 The yarn is ejected from a spinneret with a roughly flat cross-section (the length-to-width ratio of the spinneret is 5.5), and is kept in a windless insulation zone, cooled in a ring-blown cooling zone, oiled by an oiling nozzle, the brittle and damaged yarns are treated with a pre-networking device, stretched and shaped by the first and second hot rollers, interwoven by the main network device, and wound on a winder to produce 120dtex / 36f wavy, flat, low-strength polyester fully-drawn yarn.

[0081] Among them, the preparation process parameters of low-strength polyester fully drawn yarn are: the pump pressure after the melt booster pump is 18MPa, the outlet temperature of the melt cooler is 276°C, the temperature of the spinning box is 283°C, the height of the windless insulation zone is 75mm, the cooling temperature of the annular air cooling zone is 20°C, the oiling rate is 0.95%, the angle α is 23.5°, and the surface roughness Ra of the rough surface layer is 0.88; the speed of the first hot roller is 2805m / min, the temperature of the first hot roller is 74°C, the speed of the second hot roller is 4772m / min, the temperature of the second hot roller is 120°C, and the winding speed is 4700m / min.

[0082] The physical properties of the prepared 120dtex / 36f wavy flat low-strength polyester fully drawn yarn are: fineness 119.5dtex, breaking strength 1.85cN / dtex, breaking elongation 22.1%, boiling water shrinkage 7.7%, and network density 9.5 / m.

[0083] Comparative Example 1

[0084] The method is basically the same as Example 1, except that the cross section of the spinneret hole is a round hole, and no fragile parts are set in the production system. The physical properties of the obtained polyester fully drawn yarn are: fineness 83 dtex, breaking strength 3.15 cN / dtex, breaking elongation 28%, boiling water shrinkage 7.2%, and network degree 10 / m.

[0085] Compared with Example 1, it can be seen that the breaking strength is increased by 61.5%, which is not conducive to the preparation of easy-tear cloth.

[0086] Comparative Example 2

[0087] The method is basically the same as Example 1, except that the angle α is 60°. The physical properties of the obtained polyester fully drawn yarn are: fineness 83 dtex, breaking strength 2.1 cN / dtex, breaking elongation 17%, boiling water shrinkage 6.9%, and network density 10 / m.

[0088] The silk cake has obvious hair on the surface and does not meet the factory appearance requirements.

[0089] Comparative Example 3

[0090] The method is basically the same as Example 1, except that the fragile part is arranged between the pre-network device and the U-shaped ceramic part. The physical properties of the obtained fully drawn polyester yarn are: fineness 83 dtex, breaking strength 2.8 cN / dtex, breaking elongation 22%, boiling water shrinkage 7.1%, and network degree 9 pieces / m.

[0091] Compared with Example 1, it can be seen that the breaking strength is increased by 43.6%, which is not conducive to the preparation of easy-tear cloth.

[0092] Comparative Example 4

[0093] The method is basically the same as Example 1, except that the surface roughness Ra of the rough surface layer is 3. The physical properties of the obtained fully drawn polyester yarn are: fineness 83 dtex, breaking strength 2.1 cN / dtex, breaking elongation 19%, boiling water shrinkage 7.2%, and network density 10 / m.

[0094] The silk cake has obvious hair on the surface and does not meet the factory appearance requirements.

[0095] 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.

[0096] 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 low-strength polyester fully drawn yarn, characterized in that: The preparation method comprises: The polyester melt is sprayed out into filaments through a spinneret with a flat cross section. After cooling and oiling, the filaments are brought into friction contact with fragile parts with a rough surface layer, and then enter the pre-netting device for processing, stretching and shaping, and the main netting is netted and entangled. Among them, the surface roughness Ra of the rough surface layer is 0.5-1.5, the wire strip located between the fragile part and the pre-network device enters the pre-network device at an angle α, and the acute angle between the wire strip entering the pre-network device and the vertical normal of the end face of the pre-network device for the wire strip to enter is the angle α, and the angle α is 10°-30°.

2. The method for preparing low-strength polyester fully drawn yarn according to claim 1, characterized in that: The aspect ratio of the spinneret hole with a flat cross section is greater than or equal to 5; and / or the polyester melt is obtained by melting a polyester raw material, and the intrinsic viscosity of the polyester raw material is less than or equal to 0.58 dL / g.

3. The method for preparing low-strength polyester fully drawn yarn according to claim 1, characterized in that: The aspect ratio of the spinneret hole with a flat cross section is 5-8; and / or, the polyester melt is obtained by melting a polyester raw material, and the intrinsic viscosity of the polyester raw material is 0.52-0.57 dL / g; and / or, the polyester melt is a cationic dyeable polyester melt.

4. The method for preparing low-strength polyester fully drawn yarn according to claim 1, characterized in that: The surface roughness Ra of the rough surface layer is 0.7-1.1; and / or the angle α is 15°-25°.

5. The method for preparing low-strength polyester fully drawn yarn according to claim 1, characterized in that: The fragile part includes a mounting portion and a fragile portion arranged on the mounting portion, the rough surface layer is formed on the surface of the fragile portion, the fragile portion includes a wire hole allowing the wire to pass through and a clearance gap allowing the wire to freely enter and exit, and the wire hole is connected to the clearance gap.

6. The method for preparing low-strength polyester fully drawn yarn according to claim 5, characterized in that: The rough surface layer has at least two locations in contact with the wire; and / or the wire enters from a lower portion of a rear portion of the wire hole and extends out from an upper portion of a front portion of the wire hole.

7. The method for preparing low-strength polyester fully drawn yarn according to claim 1, characterized in that: The material of the fragile parts is ceramic; and / or, the implementation method of preparing the low-strength polyester fully stretched yarn includes: transporting the polyester melt through a melt pipeline, passing through a melt booster pump, a melt cooler, and a spinning box, and then ejecting it from a spinneret hole with a flat cross section, being kept warm in a windless insulation zone, cooled in a ring-blown cooling zone, oiled by an oiling nozzle, and forming fragile damaged yarns with a rough surface layer, pre-networking and oiling, stretching and shaping by a first hot roller and a second hot roller, interlacing the main network, and winding and forming by a winding machine; wherein, the enhanced The pump pressure after the pressure pump is 16-20MPa, the outlet temperature of the melt cooler is 274-277℃, the temperature of the spinning box is 280-285℃, the height of the windless insulation zone is 50-75mm, the speed of the first hot roller is 1800-3500m / min, the temperature of the first hot roller is 60-90℃, the speed of the second hot roller is 4000-5100m / min, the temperature of the second hot roller is 80-130℃, and the winding speed is 4000-5000m / min.

8. A low-strength polyester fully-drawn yarn produced by the method for preparing a low-strength polyester fully-drawn yarn according to any one of claims 1 to 7, wherein the breaking strength of the low-strength polyester fully-drawn yarn is less than or equal to 2.2 cN / dtex.

9. The low-strength polyester fully drawn yarn according to claim 8, characterized in that: The breaking strength of the low-strength polyester fully-drawn yarn is 1.8-2.2 cN / dtex, and the breaking elongation is 20%-30%; and / or the single-filament fineness of the low-strength polyester fully-drawn yarn is 0.5-3.7 dtex.

10. Use of the low-strength fully-drawn polyester yarn according to any one of claims 1 to 7 in the preparation of medical tapes, wiring harness tapes or trademark cloths.

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