Preparation and application of fine denier PVC fiber

Abstract

The application provides a preparation and application of fine denier PVC fiber, water-soluble salt is subjected to ball milling treatment to obtain salt nanoparticles with a particle size controlled in a range of 10-100 nm, the salt nanoparticles are added into water-soluble polyester to obtain a modified polyester mixture, screw extrusion is conducted on the modified polyester mixture to obtain a blending melt; dry PVC resin and dioctyl phthalate are mixed at 80-100 DEG C to obtain a plasticized PVC mixture, screw extrusion is conducted on the plasticized PVC mixture to obtain a plasticized PVC resin melt; the blending melt and the plasticized PVC resin melt are conveyed into a spinning box for spinning and extrusion of nascent composite fibers, the nascent composite fibers are subjected to segmented temperature control cooling, and then are subjected to oiling, two-stage hot drawing and winding to obtain composite orange segment filaments, and then the composite orange segment filaments are placed in a deionized water bath to be split into single filaments, and the single filaments are subjected to water washing and drying in sequence to obtain fine denier PVC fiber.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fine denier fibers, in particular to a preparation and application of fine denier PVC fibers. BACKGROUND

[0002] Polyvinyl chloride (PVC) fibers have excellent chemical stability, weather resistance and cost advantage, and show irreplaceable application value in textile fabrics, decorative materials, industrial filtration and other fields, and the market demand continues to grow.

[0003] However, the traditional PVC fiber preparation technology has significant technical bottlenecks, which seriously restricts the performance upgrade and fine denier development: in the wet spinning process, solvent residues not only cause serious environmental and safety hazards, but also cause the formation of pore defects inside the fiber, poor uniformity of surface gloss, and difficulty in meeting the requirements of high-end applications for fiber appearance and purity; when directly preparing fine denier fibers by melt spinning, due to the narrow interval between the melting temperature and the decomposition temperature of PVC, thermal degradation (with the release of harmful gases) easily occurs during the spinning process, at the same time, the flowability of PVC melt itself is poor, and the compatibility of plasticizer with PVC matrix after addition is low, resulting in low mechanical strength of the fiber and high breakage rate during the spinning process, and it is still difficult to obtain fine denier products with a diameter less than 10 μm by direct melt spinning technology.

[0004] To break through the bottleneck of PVC fiber thinning, composite spinning-splitting technology has become the current core research direction, but there are still key problems to be solved in the existing technology: in the current mainstream sea-island composite spinning technology, the sea component is mostly pure polyester material, which has weak interfacial bonding force with the PVC island component, and is easy to delaminate during spinning or post-processing, and the splitting process needs to rely on high temperature or high pressure conditions, which easily leads to thermal degradation or structural damage of the PVC component; at the same time, the selection and addition process of the plasticizer of the PVC island component lack systematic optimization, which leads to uneven dispersion of the plasticizer in the matrix, not only weakening the plasticizing effect, but also further exacerbating the fluctuation of the mechanical properties and forming stability of the fiber.

[0005] Therefore, the development of nano-modified sea component with excellent compatibility with PVC, the optimization of plasticized PVC island component formula and the matching of spinning-cooling forming-splitting process parameters have become the core needs to break through the bottleneck of efficient and stable preparation of fine denier PVC fibers. SUMMARY

[0006] The purpose of the present application is to provide a preparation and application of fine denier PVC fibers, and to provide a nano-modified sea component suitable for PVC and an optimized plasticized island component and spinning process to realize the preparation of fine denier fibers.

[0007] To achieve the above purpose, the technical scheme provides a preparation method of fine denier PVC fibers, comprising the following steps:

[0008] S1: mixing terephthalic acid, isophthalic acid, ethylene glycol and dimethyl isophthalate sulfonate to obtain a mixture, and melt polycondensing the mixture to obtain a water-soluble polyester;

[0009] S2: taking the water-soluble salt to obtain salt nanoparticles with a particle size controlled in the range of 10-100 nm through ball milling, adding the salt nanoparticles to the water-soluble polyester to obtain a modified polyester mixture, and screw extruding the modified polyester mixture to obtain a blending melt; mixing dry PVC resin and dioctyl phthalate (DOP) at 80-100 ℃ to obtain a plasticized PVC mixture, and screw extruding the plasticized PVC mixture to obtain a plasticized PVC resin melt; conveying the blending melt and the plasticized PVC resin melt to a spinning box to spin and extrude a primary composite fiber, and cooling the primary composite fiber through segmented temperature control, and then oiling, two-stage heat drawing and winding to obtain a composite orange-ribbon filament;

[0010] S3: placing the composite orange-ribbon filament in a deionized water bath to split the filament into a single filament, and then washing and drying the single filament to obtain a fine denier PVC fiber.

[0011] In step S1, terephthalic acid and isophthalic acid are used as diacids, ethylene glycol is used as a diol, and dimethyl isophthalate sulfonate is used as a hydrophilic third monomer. The mixture of the raw materials is prepared into a water-soluble polyester through melt polycondensation.

[0012] It should be noted that terephthalic acid (TPA) and isophthalic acid (IPA) are selected as diacids in this scheme because TPA can ensure the mechanical strength and thermal stability of the polyester to adapt to spinning, and IPA can destroy the regularity of the molecular chain, so that the melt processing temperature (180 ℃) of the polyester matches the spinning temperature of the PVC and the solubility temperature is reduced to 40-55 ℃. Ethylene glycol (EG) is selected as a diol because it has high reactivity with diacids, can control the length of the molecular chain, and is environmentally friendly and economical. Dimethyl isophthalate sulfonate (DMSIP) is selected as a hydrophilic third monomer because it contains a strong hydrophilic group that can impart water solubility to the polyester, and has good compatibility with the main monomers and controllable dosage. Through melt polycondensation, solvent residues can be avoided and the performance of the polyester can be precisely controlled, and finally a water-soluble polyester that meets the subsequent requirements of composite spinning and low-temperature splitting is obtained.

[0013] In some embodiments, the molar ratio of terephthalic acid is 70-85 mol%, the molar ratio of isophthalic acid is 10-25 mol%, the molar ratio of ethylene glycol is 80-100 mol%, and the addition amount of dimethyl isophthalate sulfonate is 5-15% of the total mass of the mixture.

[0014] In some embodiments, when the mixture is subjected to melt polycondensation, the temperature is first controlled at 220-240°C and reacted for 2-4h, then the temperature is raised to 250-270°C and kept under a vacuum degree of ≤100Pa for 1-3h to obtain a water-soluble polyester. That is, the process of melt polycondensation is divided into an esterification reaction for allowing the monomers to be fully esterified, and a polycondensation reaction for allowing the monomers to be polycondensed, wherein the esterification reaction is to allow the dibasic acid (TPA, IPA) to react with the dibasic alcohol (EG) to generate an esterification product, and this stage needs a mild temperature to allow the carboxyl and hydroxyl groups to be efficiently combined, so as to avoid the EG from being volatilized or the TPA / IPA from being carbonized at a high temperature; the subsequent polycondensation reaction needs to increase the temperature and vacuumize, so as to break the balance of the esterification product, promote the molecular chain growth to form a high molecular weight polyester, and remove the byproduct water. If the one-step process is performed, the polycondensation is difficult to proceed at a low temperature, and the esterification is not sufficient at a high temperature, which is easy to cause the product to have many impurities.

[0015] It should be noted that the polyester melt processing temperature of the water-soluble polyester prepared in step S1 of the present scheme is 180°C, which matches the subsequent PVC processing temperature, and the dissolution temperature is between 40-55°C, which meets the low-temperature splitting requirement.

[0016] In step S2, the blended melt is used as the sea component, and the plasticized PVC resin melt is used as the island component, and the sea component and the island component are mixed to perform composite spinning to obtain a primary composite fiber. In the present scheme, the sea component is modified by salt nanoparticles, and the island component is plasticized and optimized, so as to solve the compatibility problem of PVC and the carrier material, and improve the spinning stability.

[0017] Specifically, regarding the preparation process of the sea component, the present scheme uses salt nanoparticles as the modified filler of the sea component, and the salt nanoparticles are uniformly dispersed in the water-soluble polyester. In this way, in the process of melt extrusion of spinning, the salt nanoparticles can produce physical embedding between the sea component and the island component, so as to weaken the phase separation of the two phases, and the salt nanoparticles are easily dissolved in water at room temperature, and can be locally dissolved at a relatively low temperature, so as to drive the sea component to quickly fall off.

[0018] In some embodiments, the water-soluble salt is selected from one or more of potassium chloride, potassium sulfate, sodium chloride, and sodium sulfate, and the particle size of the salt nanoparticles is controlled at 10-100nm. Potassium chloride, potassium sulfate, sodium chloride, and sodium sulfate are all inorganic salts that are easily soluble in water, and can be dissolved together with the water-soluble polyester in the subsequent splitting process without residual impurities. Moreover, such salts are chemically stable and do not decompose or chemically react with the polyester or PVC at a spinning processing temperature of 160-180°C, which can ensure the stability of the spinning process. In addition, the raw material cost is low and the source is extensive, which can reduce the process economic cost.

[0019] In some embodiments, the water-soluble salt is ball milled by a planetary ball mill. Specifically, zirconium oxide ball milling media with a ball-to-material ratio of 8-10:1 is used, and the rotation speed is controlled at 300-500 r / min, and the ball milling time is 2-4 h, so as to ensure that the particle size of the salt nanoparticles is uniformly controlled at 10-100 nm. The particle size of the salt nanoparticles can be detected by a laser particle size analyzer, and the particle size distribution span is ≤0.5.

[0020] In some embodiments, the salt nanoparticles are added to the water-soluble polyester in a mass ratio of (5-15):(85-95) to obtain a modified polyester mixture.

[0021] In some embodiments, the water-soluble polyester needs to be dried to reduce the water content, i.e., the salt nanoparticles are added to the dried water-soluble polyester to obtain a modified polyester mixture.

[0022] In some embodiments, the water-soluble polyester is dried at 110-130°C for 12-20 h, so that the water content of the water-soluble polyester is ≤30 ppm.

[0023] In some embodiments, the salt nanoparticles are added to the water-soluble polyester by a loss-on-ignition online adding system to obtain a modified polyester mixture.

[0024] In some embodiments, the modified polyester mixture is fed into a twin-screw extruder for screw extrusion, and a uniformly dispersed blended melt is prepared through the shearing and mixing action of the screw. The twin-screw extruder can generate a shear force and dispersion force much larger than that of a single-screw extruder through the meshing rotation of the two screws, so as to effectively break the possible micro-agglomeration of the salt nanoparticles, and through the conveying and mixing action of the screw groove, the salt nanoparticles form a dispersed state of “uniform particle size and uniform distribution” in the polyester melt.

[0025] Specifically, the length-diameter ratio of the twin-screw extruder is 36:1, the extrusion temperature is 160-180°C (160°C in the first zone, 170°C in the second zone, 180°C in the third zone, and 175°C in the die head), and the screw rotation speed is 200-300 r / min.

[0026] Regarding the preparation of the island component:

[0027] In this scheme, dioctyl phthalate is used to plasticize the PVC resin. The PVC resin itself has high melt viscosity and poor flowability, and direct spinning is prone to broken yarn. The molecular structure of the dioctyl phthalate plasticizer can effectively insert between the PVC molecular chains, weaken the intermolecular force, and under the mixing condition of 80-100°C, the dioctyl phthalate plasticizer can uniformly penetrate into the interior of the PVC resin particles to form a stable and uniform plasticizing system without the risk of delamination or precipitation, thereby avoiding the problems of fiber strength fluctuation and increased breakage rate caused by poor compatibility between the plasticizer and the PVC.

[0028] In some embodiments, the moisture content of the dried PVC resin is ≤50 ppm, and the degree of polymerization of the PVC resin is 800-1200.

[0029] Specifically, the PVC resin with a degree of polymerization of 800-1200 is dried at 60-80°C for 4-8h to obtain a dried PVC resin with a moisture content of ≤50 ppm. This has the advantage of avoiding bubbles during spinning.

[0030] In some embodiments, the mass ratio of the PVC resin to dioctyl phthalate is (80-90):(10-20).

[0031] In some embodiments, the dried PVC resin and dioctyl phthalate are added to a high-speed mixer at a mass ratio of (80-90):(10-20), the mixing temperature is controlled at 80-100°C, the stirring speed is controlled at 800-1000 r / min, and the mixture is mixed for 1-2h to allow the dioctyl phthalate to uniformly penetrate into the interior of the PVC resin particles, forming a stable plasticizing system.

[0032] In some embodiments, the plasticized PVC mixture is input into a three-screw extruder for screw extrusion to obtain a plasticized PVC resin melt. The plasticizer and PVC are uniformly mixed through the multiple high-frequency shearing of the three screws, achieving uniform plasticization.

[0033] Further, the length-diameter ratio of the three-screw extruder is 25:1, and the melting temperature is controlled at 160-180°C, with a first zone at 160°C, a second zone at 170°C, a third zone at 180°C, and a die head at 175°C.

[0034] Regarding the preparation of the nascent composite fiber:

[0035] The blended melt and the plasticized PVC resin melt are transported to the spinning box for spinning and extrusion of the nascent composite fiber.

[0036] In some embodiments, the blended melt is metered by a gear metering pump and input into the spinning box through a heat preservation melt pipeline with a heat preservation temperature of 170-180°C, and at the same time, the plasticized PVC resin melt is metered by another gear metering pump and input into the same spinning box for spinning and extrusion of the nascent composite fiber. The nascent composite fiber is subjected to segmented temperature control cooling, followed by oiling, two-stage hot drawing, and winding to obtain the composite petal silk.

[0037] In some embodiments, the box temperature of the spinning box is 170-180°C, and the temperature fluctuation is ≤±1°C.

[0038] In some embodiments, the diameter of the heat preservation melt pipeline is 10-15mm.

[0039] In some embodiments, the mixed melt is extruded under an extrusion pressure of 5-8 MPa to form nascent composite fibers.

[0040] In some embodiments, the spinneret of the spinning box is a six-lobed orange-petal composite spinneret, wherein the material of the six-lobed orange-petal composite spinneret is Hastelloy, the cross-sectional area of ​​each lobe cavity is 0.05~0.1mm², and the spinneret orifice diameter is 0.2~0.4mm. It should be noted that the six-lobed orange-petal cavity type allows the sea component (and the island component) to form a six-lobed symmetrical structure of "sea enveloping island" during spinning. This structure has natural stress concentration areas and interface gaps between each pair of lobes. During subsequent low-temperature water bath splitting, as the sea component dissolves, the stress concentration areas will break first, causing the composite fiber to automatically split into six independent PVC monofilaments without relying on strong external forces such as high-pressure water flow. At the same time, the six-lobed design can ensure splitting efficiency and, by reasonably distributing the amount of island component, make the final monofilament diameter as small as 5μm, meeting the core indicators of fine denier fibers.

[0041] In some embodiments, the mass ratio of the blended melt to the plasticized PVC resin melt is (20~40):(60~80). This is because the fiber forming state is affected by the melt pressure during the composite spinning process, and the pressure difference between the two components determines the final fiber morphology. This mass ratio is optimal, taking into account both fiber forming performance and subsequent fiber splitting processes.

[0042] In some embodiments, such as Figure 3 As shown, the segmented temperature-controlled cooling system comprises three stages: a slow-cooling hot air section 1-20cm from the spinneret, where hot air at 120-150℃ is introduced at a speed of 0.6-0.8m / s, with the air box using a ring-shaped side outlet and the airflow angled to the fiber at 30-45°; a gradient slow-cooling section 20-60cm from the spinneret, where hot air at 60-110℃ is introduced at a speed of 0.5-0.8m / s, with the airflow angled to the fiber at 45-60°; and a rapid setting section 60-110cm from the spinneret, where dry cold air at 25-30℃ is introduced at a speed of 0.2-0.5m / s, with the airflow angled to the fiber at 45-60°. This ensures that the airflow uniformly coats the composite fiber, enabling controlled cooling and setting of the nascent composite fiber.

[0043] In some embodiments, polyether-modified silicone oil with a concentration of 10-15% is used to oil the air-cooled nascent composite fibers, and the oiling rate is controlled at 0.5-1.0% to improve fiber cohesion and subsequent processability.

[0044] In some embodiments, the oiling primary composite fiber is subjected to secondary heat drawing, wherein the first drawing uses a hot roller with a diameter of 80-100mm at 60-80℃, and the drawing ratio is 3.5-4.0, to preliminarily increase the fiber orientation; the second drawing uses a hot roller at 90-110℃, and the drawing ratio is 1.0-1.5, to further refine the fiber diameter and enhance the mechanical properties.

[0045] In some embodiments, the heat-drawn primary composite fiber is wound to obtain composite orange segment yarn, with a winding speed of 1500-2500m / min, a winding tension of 50-80cN, and winding on a paper or plastic bobbin with a diameter of 76-152mm.

[0046] In step S3, the composite orange segment yarn is subjected to weight-reducing splitting to obtain fine denier PVC fiber.

[0047] In some embodiments, the water temperature of the deionized water bath is 40-55℃, and the composite orange segment yarn is placed in the deionized water bath for stirring, with a stirring speed of 100-300r / min. The weight-reducing splitting process is shown in Figure 1 As the water-soluble polyester in the sea component gradually dissolves, the salt nanoparticles are simultaneously introduced into the water with the dissolved water-soluble polyester, and due to the stress concentration effect of the six-segment orange segment structure, the DOP plasticized PVC island component is automatically split into six independent filaments during the removal of the sea component.

[0048] In some embodiments, the filaments are sequentially subjected to water washing, with a water temperature of 40-50℃, a water washing time of 10-20min, and a water amount of 50-100 times the mass of the fiber, to remove the residual polyester and salt ions.

[0049] In some embodiments, the water-washed filaments are placed in a hot air drying oven and dried at 80-100℃ for 2-4h to obtain fine denier PVC fiber.

[0050] In addition, the present scheme provides an application method of fine denier PVC fiber, i.e., after obtaining the fine denier PVC fiber, a non-woven fabric can be prepared by a hydroentangling method. In the process of preparing the non-woven fabric, the fiber is first made into a fiber web by a carding machine, wherein the basis weight of the fiber web is 30-80g / m², and then subjected to hydroentangling reinforcement treatment, with a hydroentangling pressure of 80-120bar, a hydroentangling distance of 5-10mm, and a hydroentangling path number of 3-5, to finally obtain fine denier PVC hydroentangled fabric.

[0051] Compared with the prior art, the present technical scheme has the following characteristics and beneficial effects:

[0052] 1. Compatibility and spinning stability improvement: The synthetic water-soluble polyester meets the 180℃ melt processing and 40~55℃ low-temperature dissolution characteristics at the same time, solving the processing temperature matching problem of PVC and composite components; by making water-soluble salt into 10~100nm salt nanoparticles and blending with water-soluble polyester, the salt nanoparticles can fill the interface voids of the polyester and PVC, improving the interfacial bonding force of the two components; at the same time, DOP plasticization optimization makes the PVC melt viscosity reduce by 30~50%, solving the problems of uneven melt flow and high yarn breakage rate in traditional composite spinning, and the spinning continuity is improved to more than 95%.

[0053] 2. Based on the crystallization temperature difference of the water-soluble polyester and PVC modified by salt particle blending, a segmented temperature control cooling process is designed to accurately match the crystallization characteristics of the two materials, avoiding the problems of crystallization imbalance, component interface separation and spinnability decline caused by the traditional cooling of ordinary air cooling in the production of chemical fibers, and ensuring the fiber quality and mechanical properties from the molecular structure level.

[0054] 3. Fiber thinning and performance balance: The six-petal orange petal structure cooperates with two-stage drawing, so that the diameter of the split PVC single yarn can be as small as 5μm; compared with the traditional multi-petal structure, the six-petal orange petal structure design reduces the splitting difficulty, and can realize complete splitting without high-pressure water flow, and the removal rate of nano-modified sea components is ≥99%, without residual impurities, realizing the preparation of fine denier PVC fiber.

[0055] 4. The present invention has outstanding environmental protection and economic benefits. The entire preparation process uses water as the splitting medium, there is no solvent residue problem, and it is more environmentally friendly than wet spinning; the two-stage drawing and low-temperature stirring splitting process has low energy consumption, and the water-soluble polyester can be reused by recycling the solution, reducing production costs. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 is a schematic diagram of the reduced amount of splitting of the present scheme.

[0057] Figure 2 is a scanning electron microscope photo of the fine denier fiber of Example 1 during the splitting process, (a) is the fiber morphology at 10 minutes of splitting, and (b) is the fiber morphology at 40 minutes of splitting (the same sample as the example).

[0058] Figure 3 is a schematic diagram of the segmented temperature control cooling of the composite fiber of the present scheme. DETAILED DESCRIPTION

[0059] With reference to the drawings of the embodiments of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art belong to the scope of protection of the present application.

[0060] Embodiment one

[0061] The present embodiment provides a complete preparation method of fine denier PVC fiber. The specific content is as follows:

[0062] (1) Preparation of water-soluble polyester

[0063] 20 kg of polymer monomers were weighed and mixed, in which terephthalic acid (TPA) accounted for 80 mol%, isophthalic acid (IPA) accounted for 15 mol%, ethylene glycol (EG) accounted for 90 mol%, and dimethyl isophthalate sulfonate (DMSIP) was added in an amount of 10% of the total mass of the mixture. The mixture was reacted at 230℃ for 3 hours to fully esterify the diacid and diol, and then heated to 260℃, and reacted for 2 hours under a vacuum degree ≤100 Pa to obtain a water-soluble polyester. The melt processing temperature of the obtained water-soluble polyester is 180℃, and the dissolution temperature is 40-55℃.

[0064] (2) Preparation of composite orange segment filaments

[0065] Sea component preparation: the water-soluble polyester raw material prepared above was dried at 120℃ for 16 hours to make the water content ≤30 ppm, potassium chloride (KCl) was selected as the water-soluble salt modification component, a planetary ball mill was used with zirconia balls as the medium, the ball-to-material ratio was 9:1, the rotation speed was controlled at 400 r / min, and the ball milling time was 3 hours to obtain KCl nanoparticles with an average particle size of 50 nm and a particle size distribution span of 0.40. The KCl nanoparticles were added to the dried water-soluble polyester in a mass ratio of 10:90, and a double-screw online adding system was used for mixing to obtain a modified polyester mixture. The sea component was extruded by a double-screw extruder with a screw length-diameter ratio of 36:1, the temperature was set at 160℃ in the first zone, 170℃ in the second zone, 180℃ in the third zone, and 175℃ at the die head, the screw rotation speed was 250 r / min, and the extruded blended melt was obtained.

[0066] Island component preparation: the PVC resin raw material was dried at 70℃ for 6 hours, and the dried PVC resin and dioctyl phthalate (DOP) were added to a high-speed mixer in a mass ratio of 85:15, the mixing temperature was controlled at 90℃, the stirring rotation speed was 900 r / min, and the mixing time was 1.5 hours to obtain a plasticized PVC mixture. A three-screw extruder was used with a screw length-diameter ratio of 25:1, the temperature was set at 160℃ in the first zone, 170℃ in the second zone, 180℃ in the third zone, and 175℃ at the die head, and the plasticized PVC resin melt was extruded.

[0067] Composite spinning: the blended melt and the plasticized PVC resin melt are metered by gear metering pumps in a mass ratio of 30:70, respectively, and are delivered to the spinning beam through two material paths. The spinning beam temperature is 175℃, the spinning assembly extrusion pressure is 7.5MPa, the island component assembly pressure difference is 0.5MPa, a six-petal orange petal type composite spinneret is used, the material is hastelloy, the cross-sectional area of each petal type cavity is 0.075mm2, the spinneret hole diameter is 0.3mm, and the extruded primary composite fiber is obtained.

[0068] The primary composite fiber is subjected to segmented temperature control cooling, and then is subjected to oiling, two-stage hot drawing, and winding to obtain the composite orange petal fiber. The segmented temperature control cooling process includes three stages. At a distance of 5-20cm from the spinneret, it is a slow cooling air hot section, 150℃ hot air is introduced, the air speed is 0.6m / s, the air box adopts ring-shaped side air outlet, and the air direction is at an angle of 45° with the fiber. At a distance of 20-60cm from the spinneret, it is a gradient slow cooling section, the air box adopts ring-shaped side air outlet, 100℃ hot air is introduced, the air speed is 0.5m / s, and the air direction is at an angle of 45° with the fiber. At a distance of 60-110cm from the spinneret, it is a rapid setting section, the air box adopts ring-shaped side air outlet, 25℃ dry cold air is introduced, the air speed is 0.5m / s, and the air direction is at an angle of 60° with the fiber. The spinning oil is polyether modified silicone oil with a concentration of 8.5%, and the oiling rate is 0.75%. The first-stage drawing uses 70℃ hot roller, and the drawing ratio is 3.75. The second-stage drawing uses 100℃ hot roller, and the drawing ratio is 1.25. The winding speed is 2000m / min, the winding tension is 65cN, a paper bobbin with a diameter of 114mm is used, and the composite orange petal fiber is obtained.

[0069] (3) Preparation of fine denier PVC fiber

[0070] The composite orange petal fiber is placed in a 50℃ deionized water bath, the stirring speed is 200r / min, the splitting time is 40 minutes, the island component is completely dissolved, and the single fiber is obtained. The fiber is washed in 45℃ deionized water for 15 minutes, and the water amount is 75 times the mass of the fiber. The fiber is dried in a 90℃ hot air drying box for 3 hours, and the fine denier PVC fiber is obtained.

[0071] (4) Preparation of fine denier PVC spunlace fabric

[0072] The fine denier PVC fiber obtained above is used to prepare non-woven fabric by water jet method. The fiber web is formed by carding, and the fiber web basis weight is 50g / m 2 . Water jet reinforcement is used, the water jet pressure is 100bar, the water jet distance is 7.5mm, and the water jet path number is 4, and the fine denier PVC spunlace fabric is obtained.

[0073] Example Two

[0074] This example is basically the same as Example One, except that the type of water-soluble salt is replaced to verify the effect of different salt nanoparticles. The specific content is as follows:

[0075] (1) Preparation of water-soluble polyester

[0076] 20 kg of polymerized monomers were weighed and mixed, in which terephthalic acid (TPA) accounted for 80 mol%, isophthalic acid (IPA) accounted for 15 mol%, ethylene glycol (EG) accounted for 90 mol%, and dimethyl isophthalate sulfonate (DMSIP) was added in an amount of 10% of the total mass of the mixture. The mixture was reacted at 230°C for 3 hours to fully esterify the diacids and diols, and then heated to 260°C and reacted for 2 hours under a vacuum degree of ≤100 Pa to obtain a water-soluble polyester. The melt processing temperature of the obtained water-soluble polyester was 180°C, and the dissolution temperature was 40-55°C.

[0077] (2) Preparation of composite orange segment filaments

[0078] Sea component preparation: The water-soluble polyester raw material prepared above was dried at 120°C for 16 hours to make the water content ≤30 ppm, sodium sulfate (Na2SO4) was selected as the water-soluble salt modification component, a planetary ball mill was used with zirconia balls as the medium, the ball-to-material ratio was 9:1, the rotation speed was controlled at 400 r / min, and the ball milling time was 3 hours to obtain Na2SO4 nanoparticles with an average particle size of 55 nm and a particle size distribution span of 0.45. The Na2SO4 nanoparticles were added to the dried water-soluble polyester at a mass ratio of 10:90, and a double-screw online adding system was used for mixing to obtain a modified polyester mixture. The sea component was extruded by a double-screw extruder with a screw length-diameter ratio of 36:1, the temperature was set at 160°C in the first zone, 170°C in the second zone, 180°C in the third zone, and 175°C at the die head, the screw rotation speed was 250 r / min, and the extruded blended melt was obtained.

[0079] Island component preparation: The PVC resin raw material was dried at 70°C for 6 hours, and the dried PVC resin was mixed with dioctyl phthalate (DOP) at a mass ratio of 85:15 in a high-speed mixer, the mixing temperature was controlled at 90°C, the stirring rotation speed was 900 r / min, and the mixing time was 1.5 hours to obtain a plasticized PVC mixture. A three-screw extruder was used with a screw length-diameter ratio of 25:1, the temperature was set at 160°C in the first zone, 170°C in the second zone, 180°C in the third zone, and 175°C at the die head, and the plasticized PVC resin melt was extruded.

[0080] Composite spinning: the blended melt and the plasticized PVC resin melt are metered by gear metering pumps in a mass ratio of 30:70, respectively, and are delivered to the spinning beam through two material paths. The spinning beam temperature is 175°C, the spinning assembly extrusion pressure is 7.5 MPa, the island component assembly pressure difference is 0.5 MPa, a six-petal orange petal type composite spinneret is used, the material is hastelloy, the cross-sectional area of each petal type cavity is 0.075 mm2, the spinneret hole diameter is 0.3 mm, and the extruded primary composite fiber is obtained. The primary composite fiber is subjected to segmented temperature control cooling, and then is subjected to oiling, two-stage hot drawing and winding to obtain the composite orange petal fiber. The segmented temperature control cooling process includes three stages: a slow cooling air hot section at a distance of 5-20 cm from the spinneret, 150°C hot air is introduced, the air speed is 0.6 m / s, the air box adopts ring-shaped side air outlet, the air direction is at an angle of 45° with the fiber; a gradient slow cooling section at a distance of 20-60 cm from the spinneret, the air box adopts ring-shaped side air outlet, 100°C hot air is introduced, the air speed is 0.5 m / s, the air direction is at an angle of 45° with the fiber; a rapid setting section at a distance of 60-110 cm from the spinneret, the air box adopts ring-shaped side air outlet, 25°C dry cold air is introduced, the air speed is 0.5 m / s, the air direction is at an angle of 60° with the fiber, the spinning oil is polyether modified silicone oil with a concentration of 8.5%, and the oiling rate is 0.75%. The first-stage drawing uses 70°C hot roller, the drawing ratio is 3.75, and the second-stage drawing uses 100°C hot roller, the drawing ratio is 1.25. The winding speed is 2000 m / min, the winding tension is 65 cN, a paper bobbin with a diameter of 114 mm is used, and the composite orange petal fiber is obtained.

[0081] (3) Preparation of fine denier PVC fiber

[0082] The composite orange petal fiber is placed in a 50°C deionized water bath, the stirring speed is 200 r / min, the splitting time is 40 minutes, and the island component is completely dissolved to obtain a single fiber. The fiber is washed in 45°C deionized water for 15 minutes, and the water amount is 75 times the mass of the fiber. The fiber is dried in a 90°C hot air drying oven for 3 hours to obtain the fine denier PVC fiber.

[0083] (4) Preparation of fine denier PVC spunlace fabric

[0084] The fine denier PVC fiber obtained above is used to prepare a non-woven fabric by the spunlace method. The fiber web is formed by carding, the fiber web basis weight is 50 g / m 2 . The fiber web is reinforced by spunlace, the spunlace pressure is 100 bar, the spunlace distance is 7.5 mm, and the spunlace path number is 4, and the fine denier PVC spunlace fabric is obtained.

[0085] Example Three

[0086] This example is basically the same as Example One, but the composition of the water-soluble polyester and the spinning parameters are adjusted to optimize the fiber performance. The specific content is as follows:

[0087] (1) Preparation of water-soluble polyester

[0088] 5 kg of polymerized monomers were weighed and mixed, wherein terephthalic acid (TPA) accounted for 75 mol%, isophthalic acid (IPA) accounted for 20 mol%, ethylene glycol (EG) accounted for 80 mol%, and dimethyl isophthalate sulfonate (DMSIP) was added in an amount of 12% of the total mass of the mixture. The mixture was reacted at 230°C for 3 hours to fully esterify the diacids and diols, and then heated to 260°C and reacted for 2 hours under a vacuum degree of ≤100 Pa to obtain a water-soluble polyester. The melt processing temperature of the obtained water-soluble polyester was 180°C, and the dissolution temperature was 40-55°C.

[0089] (2) Preparation of composite orange petal filaments

[0090] Sea component preparation: The water-soluble polyester raw material prepared above was dried at 120°C for 16 hours to make the water content ≤30 ppm, potassium chloride (KCl) was selected as the water-soluble salt modification component, a planetary ball mill was used, zirconia balls were used as the medium, the ball-to-material ratio was 9:1, the rotation speed was controlled at 400 r / min, and the ball milling time was 3 hours to obtain KCl nanoparticles with an average particle size of 50 nm and a particle size distribution span of 0.40. The KCl nanoparticles were added to the dried water-soluble polyester at a mass ratio of 10:90, and a double-screw online adding system was used for mixing to obtain a modified polyester mixture. The sea component was extruded by a double-screw extruder with a screw length-diameter ratio of 36:1, the temperature was set at 160°C in the first zone, 170°C in the second zone, 180°C in the third zone, and 175°C at the die head, the screw rotation speed was 250 r / min, and the extruded blended melt was obtained.

[0091] Island component preparation: The PVC resin raw material was dried at 70°C for 6 hours, and the dried PVC resin and dioctyl phthalate (DOP) were added to a high-speed mixer at a mass ratio of 85:15, the mixing temperature was controlled at 90°C, the stirring rotation speed was 900 r / min, and the mixing time was 1.5 hours to obtain a plasticized PVC mixture. A three-screw extruder was used with a screw length-diameter ratio of 25:1, the temperature was set at 160°C in the first zone, 170°C in the second zone, 180°C in the third zone, and 175°C at the die head, and the plasticized PVC resin melt was extruded.

[0092] Composite spinning: the blended melt and the plasticized PVC resin melt above are metered by gear metering pumps respectively at a mass ratio of 40:60, and are delivered to the spinning beam through two material paths. The spinning beam temperature is 175°C, the spinning assembly extrusion pressure is 7.5 MPa, the island component assembly pressure difference is 0.5 MPa, a six-petal orange petal type composite spinneret is used, the material is hastelloy, the cross-sectional area of each petal type cavity is 0.075 mm2, the spinneret hole diameter is 0.3 mm, and the extruded primary composite fiber is obtained. The primary composite fiber is subjected to segmented temperature control cooling, and then is subjected to oiling, two-stage hot drawing, and winding to obtain the composite orange petal fiber, wherein the segmented temperature control cooling process comprises three stages, a slow cooling air hot section at a distance of 5-20 cm from the spinneret, 150°C hot air is introduced, the air speed is 0.6 m / s, the air box adopts ring-shaped side air outlet, and the air direction is at an angle of 45° with the fiber; a gradient slow cooling section at a distance of 20-60 cm from the spinneret, the air box adopts ring-shaped side air outlet, 100°C hot air is introduced, the air speed is 0.5 m / s, and the air direction is at an angle of 45° with the fiber; a rapid setting section at a distance of 60-110 cm from the spinneret, the air box adopts ring-shaped side air outlet, 25°C dry cold air is introduced, the air speed is 0.5 m / s, and the air direction is at an angle of 60° with the fiber, the spinning oil is polyether modified silicone oil with a concentration of 8.5%, and the oiling rate is 0.75%. The first-stage drawing uses 70°C hot roller, the drawing ratio is 4.0, the second-stage drawing uses 100°C hot roller, and the drawing ratio is 1.5. The winding speed is 2000 m / min, the winding tension is 65 cN, a paper bobbin with a diameter of 114 mm is used, and the composite orange petal fiber is obtained.

[0093] (3) Preparation of fine denier PVC fiber

[0094] The composite orange petal fiber is placed in a 50°C deionized water bath, the stirring speed is 200 r / min, the splitting time is 40 minutes, the island component is completely dissolved, and a single fiber is obtained. The fiber is washed in 45°C deionized water for 15 minutes, and the water amount is 75 times the mass of the fiber. The fiber is dried in a 90°C hot air drying box for 3 hours, and a fine denier PVC fiber is obtained.

[0095] (4) Preparation of fine denier PVC spunlace fabric

[0096] The fine denier PVC fiber obtained above is used to prepare a non-woven fabric by the spunlace method, the fabric is formed by carding, the web basis weight is 50 g / m 2 . The fabric is reinforced by spunlace, the spunlace pressure is 100 bar, the spunlace distance is 7.5 mm, the spunlace path number is 4, and a fine denier PVC spunlace fabric is obtained.

[0097] Comparative Example One

[0098] In this comparative example, no water-soluble salt is added, so as to verify the effect of the island component modification. The specific content is as follows:

[0099] (1) Preparation of water-soluble polyester

[0100] 20 kg of polymerized monomers were weighed and mixed, wherein terephthalic acid (TPA) accounted for 80 mol%, isophthalic acid (IPA) accounted for 15 mol%, ethylene glycol (EG) accounted for 90 mol%, and dimethyl isophthalate sulfonate (DMSIP) was added in an amount of 10% of the total mass of the mixture. The mixture was reacted at 230°C for 3 hours to fully esterify the diacids and diols, and then heated to 260°C and reacted for 2 hours under a vacuum degree of ≤100 Pa to obtain a water-soluble polyester. The melt processing temperature of the obtained water-soluble polyester was 180°C, and the dissolution temperature was 40-55°C.

[0101] (2) Preparation of composite orange petal filaments

[0102] Sea component preparation: The water-soluble polyester raw material prepared above was dried at 120°C for 16 hours to make the water content ≤30 ppm, and a water-soluble polyester melt was prepared using a double-screw extruder with a screw length-diameter ratio of 36:1, temperature zone 1 of 160°C, temperature zone 2 of 170°C, temperature zone 3 of 180°C, and a die head of 175°C, and a screw rotation speed of 250 r / min.

[0103] Island component preparation: The PVC resin raw material was dried at 70°C for 6 hours, and the dried PVC resin and dioctyl phthalate (DOP) were added to a high-speed mixer at a mass ratio of 85:15, the mixing temperature was controlled at 90°C, the stirring speed was 900 r / min, and the mixture was mixed for 1.5 hours to obtain a plasticized PVC mixture. A three-screw extruder with a screw length-diameter ratio of 25:1 was used to set the temperature zone 1 at 160°C, the temperature zone 2 at 170°C, the temperature zone 3 at 180°C, and the die head at 175°C, and the plasticized PVC resin melt was extruded.

[0104] Composite spinning: the above water-soluble polyester melt and plasticized PVC resin melt are metered by gear metering pumps at a mass ratio of 30:70, respectively, and transported to the spinning beam through two material paths. The spinning beam temperature is 175°C, the spinning assembly extrusion pressure is 7.5 MPa, the island component assembly pressure difference is 0.5 MPa, a six-petal orange petal type composite spinneret is used, the material is hastelloy, the cross-sectional area of each petal type cavity is 0.075 mm2, the spinneret hole diameter is 0.3 mm, and the extruded primary composite fiber is obtained. The primary composite fiber is subjected to segmented temperature control cooling, and then is oiled, two-stage hot drawing, and wound to obtain a composite orange petal fiber. The segmented temperature control cooling process includes three stages: a slow cooling air hot section at a distance of 5-20 cm from the spinneret, 150°C hot air is introduced, the air speed is 0.6 m / s, the air box uses ring-shaped side air outlet, and the air direction is at an angle of 45° with the fiber; a gradient slow cooling section at a distance of 20-60 cm from the spinneret, the air box uses ring-shaped side air outlet, 100°C hot air is introduced, the air speed is 0.5 m / s, and the air direction is at an angle of 45° with the fiber; a rapid setting section at a distance of 60-110 cm from the spinneret, the air box uses ring-shaped side air outlet, 25°C dry cold air is introduced, the air speed is 0.5 m / s, and the air direction is at an angle of 60° with the fiber. The spinning oil is polyether modified silicone oil with a concentration of 8.5%, and the oiling rate is 0.75%. The first-stage drawing uses 70°C hot roller, the drawing ratio is 3.75, and the second-stage drawing uses 100°C hot roller, the drawing ratio is 1.25. The winding speed is 2000 m / min, the winding tension is 65 cN, a paper bobbin with a diameter of 114 mm is used, and the composite orange petal fiber is obtained.

[0105] (3) Preparation of PVC fiber

[0106] The composite orange petal fiber is placed in a 50°C deionized water bath, the stirring speed is 200 r / min, the splitting time is 40 minutes, and the water washing is carried out in 45°C deionized water for 15 minutes, the water amount is 75 times the mass of the fiber. Drying in a 90°C hot air drying oven for 3 hours to obtain the PVC fiber.

[0107] (4) Preparation of PVC hydroentangled fabric

[0108] The above obtained PVC fiber is used to prepare non-woven fabric by hydroentanglement, the web is carded, the web basis weight is 50 g / m 2 . Hydroentanglement reinforcement is adopted, the hydroentanglement pressure is 100 bar, the hydroentanglement distance is 7.5 mm, and the hydroentanglement path number is 4, and the PVC hydroentangled fabric is obtained.

[0109] Comparative Example Two

[0110] In this comparative example, no DOP plasticizer is added, to verify the effect of island component modification. The specific content is as follows:

[0111] (1) Preparation of water-soluble polyester

[0112] 20 kg of polymerized monomers were weighed and mixed, wherein terephthalic acid (TPA) accounted for 80 mol%, isophthalic acid (IPA) accounted for 15 mol%, ethylene glycol (EG) accounted for 90 mol%, and dimethyl isophthalate sulfonate (DMSIP) was added in an amount of 10% of the total mass of the mixture. The mixture was reacted at 230°C for 3 hours to fully esterify the diacids and diols, and then heated to 260°C and reacted for 2 hours under a vacuum degree of ≤100 Pa to obtain a water-soluble polyester. The melt processing temperature of the obtained water-soluble polyester was 180°C, and the dissolution temperature was 40-55°C.

[0113] (2) Preparation of composite orange petal filaments

[0114] Sea component preparation: The water-soluble polyester raw material prepared above was dried at 120°C for 16 hours to make the water content ≤30 ppm, potassium chloride (KCl) was selected as the water-soluble salt modification component, a planetary ball mill was used with zirconia balls as the medium, the ball-to-material ratio was 9:1, the rotation speed was controlled at 400 r / min, and the ball milling time was 3 hours to obtain KCl nanoparticles with an average particle size of 50 nm and a particle size distribution span of 0.40. The KCl nanoparticles were added to the dried water-soluble polyester at a mass ratio of 10:90, and a double-screw online adding system was used for mixing to obtain a modified polyester mixture. The sea component was prepared by extruding the blended melt using a double-screw extruder with a screw length-diameter ratio of 36:1, the temperature was set at 160°C in the first zone, 170°C in the second zone, 180°C in the third zone, and 175°C at the die head, the screw rotation speed was 250 r / min.

[0115] Island component preparation: The PVC resin raw material was dried at 70°C for 6 hours, and a three-screw extruder was used with a screw length-diameter ratio of 25:1, the temperature was set at 160°C in the first zone, 170°C in the second zone, 180°C in the third zone, and 175°C at the die head to extrude the PVC resin melt.

[0116] Composite spinning: the blended melt and PVC resin melt above are metered by gear metering pumps respectively according to a mass ratio of 30:70, and are delivered to the spinning beam through two material paths. The spinning beam temperature is 175°C, the spinning assembly extrusion pressure is 7.5 MPa, the island component assembly pressure difference is 0.5 MPa, a six-petal orange petal type composite spinneret is used, the material is hastelloy, the sectional area of each petal type cavity is 0.075 mm2, the spinneret hole diameter is 0.3 mm, and the extruded primary composite fiber is obtained. The primary composite fiber is subjected to segmented temperature control cooling, and then is subjected to oiling, two-stage hot drawing, and winding to obtain the composite orange petal fiber, wherein the segmented temperature control cooling process comprises three stages, a slow cooling air hot section at a distance of 5-20 cm from the spinneret, 150°C hot air is introduced, the air speed is 0.6 m / s, the air box adopts ring-shaped side air outlet, and the air direction is at an angle of 45° with the fiber; a gradient slow cooling section at a distance of 20-60 cm from the spinneret, the air box adopts ring-shaped side air outlet, 100°C hot air is introduced, the air speed is 0.5 m / s, and the air direction is at an angle of 45° with the fiber; a rapid setting section at a distance of 60-110 cm from the spinneret, the air box adopts ring-shaped side air outlet, 25°C dry cooling air is introduced, the air speed is 0.5 m / s, and the air direction is at an angle of 60° with the fiber, the spinning oil is polyether modified silicone oil with a concentration of 8.5%, and the oiling rate is 0.75%. The first-stage drawing adopts 70°C hot roller, the drawing ratio is 3.75, the second-stage drawing adopts 100°C hot roller, and the drawing ratio is 1.25. The winding speed is 2000 m / min, the winding tension is 65 cN, a paper bobbin with a diameter of 114 mm is used, and the composite orange petal fiber is obtained.

[0117] (3) Preparation of fine denier PVC fiber

[0118] The composite orange petal fiber is placed in a 50°C deionized water bath, the stirring speed is 200 r / min, the splitting time is 40 minutes, the island component is completely dissolved, and a single fiber is obtained. The fiber is washed in 45°C deionized water for 15 minutes, and the water amount is 75 times the mass of the fiber. The fiber is dried in a 90°C hot air drying box for 3 hours, and a fine denier PVC fiber is obtained.

[0119] (4) Preparation of fine denier PVC spunlace fabric

[0120] The fine denier PVC fiber obtained above is used to prepare a non-woven fabric by a water jet method, the fabric is carded into a web, the web basis weight is 50 g / m 2 . The fabric is reinforced by water jet, the water jet pressure is 100 bar, the water jet distance is 7.5 mm, and the water jet path number is 4, and a fine denier PVC spunlace fabric is obtained.

[0121] Comparative Example Three

[0122] In this comparative example, the six-petal orange petal structure is not selected, so as to verify the influence of the spinneret structure on the fiber thinning. The specific content is as follows:

[0123] (1) Preparation of water-soluble polyester

[0124] 20 kg of polymerized monomers were weighed and mixed, wherein terephthalic acid (TPA) accounted for 80 mol%, isophthalic acid (IPA) accounted for 15 mol%, ethylene glycol (EG) accounted for 90 mol%, and dimethyl isophthalate sulfonate (DMSIP) was added in an amount of 10% of the total mass of the mixture. The mixture was reacted at 230°C for 3 hours to fully esterify the diacids and diols, and then heated to 260°C and reacted for 2 hours under a vacuum degree of ≤100 Pa to obtain a water-soluble polyester. The melt processing temperature of the obtained water-soluble polyester was 180°C, and the dissolution temperature was 40-55°C.

[0125] (2) Preparation of composite fibers

[0126] Sea component preparation: The water-soluble polyester raw material prepared above was dried at 120°C for 16 hours to make the water content ≤30 ppm, and a water-soluble polyester melt was prepared using a double-screw extruder with a screw length-diameter ratio of 36:1, temperature zone 1 of 160°C, temperature zone 2 of 170°C, temperature zone 3 of 180°C, and a die head of 175°C, and a screw rotation speed of 250 r / min.

[0127] Island component preparation: The PVC resin raw material was dried at 70°C for 6 hours, and the dried PVC resin and dioctyl phthalate (DOP) were added to a high-speed mixer at a mass ratio of 85:15, the mixing temperature was controlled at 90°C, the stirring speed was 900 r / min, and the mixture was mixed for 1.5 hours to obtain a plasticized PVC mixture. A three-screw extruder with a screw length-diameter ratio of 25:1 was used to set the temperature zone 1 at 160°C, the temperature zone 2 at 170°C, the temperature zone 3 at 180°C, and the die head at 175°C, and the plasticized PVC resin melt was extruded.

[0128] Composite spinning: the above water-soluble polyester melt and plasticized PVC resin melt are metered by gear metering pumps in a mass ratio of 30:70, respectively, and transported to the spinning beam through two material paths. The spinning beam temperature is 175°C, the spinning assembly extrusion pressure is 7.5 MPa, the island component assembly pressure difference is 0.5 MPa, a round hole composite spinneret is used, the material is hastelloy, the spinneret hole diameter is 0.3 mm, and the extruded primary composite fiber is obtained. The primary composite fiber is subjected to segmented temperature control cooling, and then is oiled, two-stage hot drawing, and wound to obtain composite orange petal silk, wherein the segmented temperature control cooling process is carried out on the composite fiber cooling. The segmented temperature control cooling process includes three stages, 5-20 cm away from the spinneret is a slow cooling air hot section, 150°C hot air is introduced, the air speed is 0.6 m / s, the air box adopts ring-shaped side air outlet, and the air direction is at an angle of 45° with the fiber; 20-60 cm away from the spinneret is a gradient slow cooling section, the air box adopts ring-shaped side air outlet, 100°C hot air is introduced, the air speed is 0.5 m / s, and the air direction is at an angle of 45° with the fiber; 60-110 cm away from the spinneret is a rapid setting section, the air box adopts ring-shaped side air outlet, 25°C dry cold air is introduced, the air speed is 0.5 m / s, and the air direction is at an angle of 60° with the fiber. The spinning oil is polyether modified silicone oil with a concentration of 8.5%, and the oiling rate is 0.75%. The first-stage drawing uses 70°C hot roller, and the drawing ratio is 3.75. The second-stage drawing uses 100°C hot roller, and the drawing ratio is 1.25. The winding speed is 2000 m / min, the winding tension is 65 cN, a paper bobbin with a diameter of 114 mm is used, and the composite primary silk is obtained.

[0129] (3) Preparation of PVC fiber

[0130] Since the round spinneret cannot form an orange petal structure, the primary fiber is a single round cross section, and the subsequent splitting step cannot automatically split into multiple filaments, so only water washing and drying are performed to obtain a single PVC fiber.

[0131] (4) Preparation of PVC spunlace fabric

[0132] The above obtained PVC fiber is used to prepare non-woven fabric by water jet method, the fiber web is formed by carding, the fiber web basis weight is 50 g / m 2 . Water jet reinforcement is adopted, the water jet pressure is 100 bar, the water jet distance is 7.5 mm, and the water jet path number is 4, and the PVC spunlace fabric is obtained.

[0133] Test examples:

[0134] The fibers and non-woven fabrics obtained in the above examples and comparative examples are tested for performance, including fiber diameter, breakage rate, sea component removal rate, spinning continuity, and non-woven fabric hand feeling. The test method is as follows:

[0135] Fine diameter test: the fiber morphology is observed using a scanning electron microscope (SEM), the diameter of a single filament is measured at random, and the average value and minimum value are calculated.

[0136] Breakage rate test: During spinning, the number of breakage per 10,000 meters of fiber is recorded, and the breakage rate is calculated (breakage rate = breakage number / total spinning length x 100%).

[0137] Sea component removal rate test: The mass change of the fiber before and after splitting is measured by weight method, and the removal rate is calculated (removal rate = (1 - fiber mass after splitting / complex yarn mass before splitting) x 100%).

[0138] Spinning continuity: Based on the breakage rate.

[0139] Spunlace fabric hand feeling test: A subjective evaluation method is used to comprehensively judge the smoothness, fullness, elasticity and other properties of the spunlace fabric by touch and visual perception.

[0140] The results are shown in Table 1:

[0141] Table 1 Fiber performance parameters corresponding to different examples

[0142]

[0143] Note: Hand feeling grade: 1-very soft, 2-soft, 3- relatively soft, 4- relatively hard, 5-hard, 6-very hard.

[0144] Analysis and conclusion:

[0145] Examples one, two and three successfully prepared fine denier PVC fibers, the average diameter of the fiber was ≤5.8 μm, the minimum diameter could reach 4.9 μm, the breakage rate was ≤2.8%, and the sea component removal rate was ≥99.3%, proving that the scheme is effective. The hand feeling of the spunlace fabric prepared by fine denier PVC fiber is very soft.

[0146] Comparative example one (without salt nanoparticles) shows low sea component removal rate and relatively thick fiber diameter, and there are still unsplit thick fibers in the sample, with a diameter of 27.1 μm, confirming the promoting effect of salt nanoparticles on interface bonding and splitting. The interlacing of thick and thin fibers makes the hand feeling of the prepared spunlace fabric relatively soft.

[0147] Comparative example two (without DOP plasticization) has a significantly increased breakage rate, proving the key role of DOP plasticization in spinning stability. The hand feeling of the prepared spunlace fabric is soft.

[0148] Comparative example three (non-orange petal structure) cannot split fine denier fibers, with a diameter much greater than 10 μm, verifying the necessity of the six-petal orange petal structure for fiber thinning. The hand feeling of the spunlace fabric prepared by thick PVC fiber is hard.

[0149] Those skilled in the art should understand that each technical feature of the above embodiments can be combined arbitrarily, and for the sake of brevity, each technical feature in the above embodiments is not described in all possible combinations, however, as long as the combination of the technical features does not exist, it should be considered as the scope of the description.

[0150] The above embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it should not be understood as the limitation of the scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the appended claims.

Claims

1. A process for the production of fine denier PVC fibres characterised in that, The method comprises the following steps: S1: mixing terephthalic acid, isophthalic acid, ethylene glycol and dimethyl isophthalate sulfonate to obtain a mixture, and melt polycondensing the mixture to obtain a water-soluble polyester; S2: ball-milling a water-soluble salt to obtain salt nanoparticles with a particle size controlled in a range of 10-100 nm, adding the salt nanoparticles to the water-soluble polyester to obtain a modified polyester mixture, and screw extruding the modified polyester mixture to obtain a blending melt; mixing dry PVC resin and dioctyl phthalate at 80-100 ℃ to obtain a plasticized PVC mixture, and screw extruding the plasticized PVC mixture to obtain a plasticized PVC resin melt; conveying the blending melt and the plasticized PVC resin melt to a spinning box to perform spinning and extrude a primary composite fiber, and segmentally controlling temperature cooling the primary composite fiber, and then performing oiling, two-stage heat drawing and winding to obtain a composite orange segment yarn; S3: placing the composite orange segment yarn in a deionized water bath to split the yarn into a single yarn, and sequentially performing water washing and drying on the single yarn to obtain a fine denier PVC fiber.

2. The process for the preparation of fine denier PVC fibers as claimed in claim 1 wherein, The mole ratio of terephthalic acid is 70-85 mol%, the mole ratio of isophthalic acid is 10-25 mol%, the mole ratio of ethylene glycol is 80-100 mol%, and the addition amount of dimethyl isophthalate sulfonate is 5-15% of the total mass of the mixture.

3. The method of making fine denier PVC fibers according to claim 1, wherein, When melt polycondensing the mixture, first, the temperature is controlled in a range of 220-240 ℃ and reacted for 2-4 h, then the temperature is increased to 250-270 ℃ and kept a vacuum degree ≤100 Pa, and reacted for 1-3 h to obtain the water-soluble polyester.

4. The method of making fine denier PVC fibers according to claim 1, characterized in that, The water-soluble salt is selected from one or more of potassium chloride, potassium sulfate, sodium chloride and sodium sulfate.

5. The method of making fine denier PVC fibers according to claim 1, wherein, The salt nanoparticles are added to the water-soluble polyester to obtain the modified polyester mixture according to a mass ratio of (5-15):(85-95).

6. The method of making fine denier PVC fibers according to claim 1, wherein, The water content in the dry PVC resin is ≤50 ppm, and the polymerization degree of the PVC resin is 800-1200.

7. The method of making fine denier PVC fibers according to claim 1, wherein, The mass ratio of the PVC resin to dioctyl phthalate is (80-90):(10-20).

8. The method of making fine denier PVC fibers according to claim 1, wherein, The spinneret plate of the spinning box is a six-segment orange segment type composite spinneret plate, wherein the sectional area of each segment type cavity of the six-segment orange segment type composite spinneret plate is 0.05-0.1 mm², and the spinneret hole diameter is 0.2-0.4 mm.

9. The method of making fine denier PVC fibers according to claim 1, wherein, The plasticized PVC mixture is input into a three-screw extruder to perform screw extrusion to obtain the plasticized PVC resin melt, the screw length-diameter ratio of the three-screw extruder is 25:1, and the melting temperature is controlled in a range of 160-180 ℃, wherein the first zone is 160 ℃, the second zone is 170 ℃, the third zone is 180 ℃, and the die head is 175 ℃.

10. The method of making fine denier PVC fibers according to claim 1, wherein, The segmented temperature control cooling comprises three stages. A slow cooling air hot section is 1-20 cm away from the spinneret, 120-150 DEG C hot air is passed, the air speed is 0.6-0.8 m / s, the air box adopts annular side air outlet, the air direction is at an angle of 30-45 DEG with the fiber. A gradient slow cooling section is 20-60 cm away from the spinneret, the air box adopts annular side air outlet, 60-110 DEG C hot air is passed, the air speed is 0.5-0.8 m / s, the air direction is at an angle of 45-60 DEG with the fiber. A fast setting section is 60-110 cm away from the spinneret, dry cooling air of 25-30 DEG C is passed, the air speed is 0.2-0.5 m / s, the air direction is at an angle of 45-60 DEG with the fiber, and the air field is uniformly wrapped around the composite fiber.

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