Polyphenylene sulfide sea-island composite fiber and preparation method therefor, polyphenylene sulfide fiber, and use

Abstract

Disclosed in the present invention are a polyphenylene sulfide sea-island composite fiber and a preparation method therefor, a polyphenylene sulfide fiber, and a use. In the polyphenylene sulfide sea-island composite fiber, a sea component is a polymer A, and an island component is a blend of polyphenylene sulfide and a polymer B, wherein the polymer A is a polyester-based polymer, a polyamide-based polymer, or a polyolefin-based polymer, and the polymer B and the polymer A are homologous polymers. In the cross section of the composite fiber, the island component has an average diameter of 0.100 μm to 10.000 μm. The polyphenylene sulfide sea-island composite fiber has good sea-island compatibility, and the polyphenylene sulfide fiber obtained after reduction treatment of the polyphenylene sulfide sea-island composite fiber has good processability, a high specific surface area, and excellent physical properties.

Description

Polyphenylene sulfide island-sea composite fiber, its preparation method and application of polyphenylene sulfide fiber Technical Field

[0001] This invention relates to a polyphenylene sulfide island-sea composite fiber and polyphenylene sulfide fiber, specifically, to an island-sea composite fiber in which the islands are blends of polyphenylene sulfide and other polymers, and to polyphenylene sulfide fiber obtained by weight reduction treatment of the island-sea composite fiber. Background Technology

[0002] In the molecular structure of polyphenylene sulfide (PPS), sulfur atoms and benzene rings are arranged in an orderly manner to form highly stable chemical bonds. This gives it the characteristics of high temperature resistance, radiation resistance, high flame retardancy, high dimensional stability, solvent resistance, chemical corrosion resistance, and electrical insulation after it is made into fibers. It has been widely used in fire-retardant fabrics, decorative fabrics, clothing fabrics, high temperature filter materials, electrical insulation materials, and alkaline electrolytic cell diaphragms.

[0003] In existing technologies, polyphenylene sulfide (PPS) is typically used as the island component and other easily soluble polymers as the sea component to form PPS island-island composite fibers. These fibers are then subjected to weight reduction processing to obtain ultra-fine PPS fibers. However, the cross-sectional shape of this type of PPS island-island composite fiber is poor, and the sea component is prone to breakage and the island component to peel off, which adversely affects subsequent processing.

[0004] Chinese patent CN113151930A discloses a method for preparing island-type polyphenylene sulfide (PPS) microfiber. The method involves melt-blending and granulating three types of PPS with melt indices of 30–100 g / 10 min, 100–300 g / 10 min, and 500–12000 g / 10 min, respectively. This granulation is then followed by melt spinning with an alkali-soluble polyester to obtain composite island-type fibers. After weight reduction treatment, PPS microfiber is obtained. While this technology improves the flowability of PPS to some extent, low-viscosity PPS is prone to decomposition during melt spinning, generating small molecule foreign matter and accompanied by severe fuming, contaminating the spinning assembly and causing fiber breakage. Furthermore, when the number of islands on the cross-section of the composite island-type fiber is small, the overall contact area between PPS and polyester is small, making the island components prone to peeling off, and leading to problems such as fiber breakage and fuzzing during processing. Summary of the Invention

[0005] The purpose of this invention is to provide a polyphenylene sulfide island composite fiber with good island compatibility, and a polyphenylene sulfide fiber with high specific surface area obtained by reducing the amount of sea components removed from the polyphenylene sulfide island composite fiber.

[0006] The technical solution of this invention is:

[0007] A polyphenylene sulfide island-island composite fiber, wherein the island component is polymer A, and the island component is a blend of polyphenylene sulfide and polymer B; wherein polymer A is a polyester polymer, polyamide polymer, or polyolefin polymer, and polymer B is a homologous polymer to polymer A; the average diameter of the island component in the cross-section of the composite fiber is 0.100–10.000 μm.

[0008] The content of polymer B is preferably 1 to 50 wt% of the island component.

[0009] On the cross-section of the composite fiber, the area of ​​all island components preferably accounts for 50-95% of the cross-sectional area.

[0010] The distance between the outermost island and the fiber surface on the cross-section of the composite fiber is preferably 0.10 to 3.00 μm.

[0011] In the cross-section along the fiber axis of the composite fiber, polymer B in the island component is preferably in the form of a strip, and the aspect ratio of the strip is preferably above 2.0.

[0012] Polyphenylene sulfide (PPS) fiber is obtained by reducing the amount of PPS sea-island composite fiber to remove sea components. The surface of the PPS fiber has linear grooves, and each 400 μm... 2 The number of linear trenches with an aspect ratio of 2.0 or higher within the specified range is 10 or more. The depth of the linear trenches is preferably 10 nm or more.

[0013] The content of polymer B in the polyphenylene sulfide fiber is preferably below 10.0 wt%.

[0014] The strength of the polyphenylene sulfide fiber is preferably 2.5 to 6.0 cN / dtex.

[0015] This invention also provides a method for preparing the above-mentioned polyphenylene sulfide island-island composite fiber, wherein polymer A is used as the sea component, and a blend of polyphenylene sulfide and polymer B is used as the island component, and island-island composite spinning is performed to obtain polyphenylene sulfide island-island composite fiber; wherein polymer A is a polyester polymer, a polyamide polymer, or a polyolefin polymer, and polymer B is a homologous polymer to polymer A. Preferably, the content of polymer B in the island component is 1.0–50.0 wt%; during the spinning process, the speed of the first roller is preferably below 2200 m / min.

[0016] This invention increases the compatibility of marine and island components in island-island composite fibers by blending island components with polymers homologous to marine components, thereby improving the productivity of the composite fibers. The polyphenylene sulfide (PPS) fibers after weight reduction treatment exhibit good processability, high specific surface area, and excellent physical properties. Therefore, the PPS composite fibers and PPS fibers of this invention are suitable for preparing various fiber structures. These fiber structures include filaments, staple fibers, diaphragms, nonwoven fabrics, and composite materials. Attached Figure Description

[0017] Figure 1 is a schematic diagram of the surface of polyphenylene sulfide fiber (after weight reduction treatment) as one embodiment.

[0018] Figure 2 is a schematic cross-sectional view of polyphenylene sulfide island composite fiber as one embodiment.

[0019] Figure 3 is a schematic cross-sectional view of polyphenylene sulfide island composite fiber as one embodiment.

[0020] Figure 4 is a schematic diagram of fiber laying in test method (5). Detailed Implementation

[0021] In existing technologies, polyphenylene sulfide (PPS) is typically used as the island component and other readily soluble polymers as the sea component to form PPS island composite fibers. These fibers are then subjected to weight reduction processing to obtain ultra-fine PPS fibers. However, due to the high viscosity and poor flowability of PPS, spinning temperatures typically need to reach above 320°C; while the spinning temperature of readily soluble polymers used as sea components is usually below 300°C. The significant viscosity difference between the island and sea components during high-temperature spinning easily leads to poor cross-sectional shape of the composite fibers. Furthermore, the sea components are prone to decomposition at high temperatures, generating fumes that contaminate spinning components, cause fiber drift, and fiber breakage, severely reducing production efficiency and increasing production costs.

[0022] The polyphenylene sulfide (PPS) island-island composite fiber of this invention has an island component composed of polymer A and an island component composed of a blend of PPS and polymer B. Polymer A is a polyester, polyamide, or polyolefin polymer, and polymer B is a homologous polymer to polymer A. By adding high-flowability polymer B to the island component, the overall viscosity and spinning temperature of the island component can be effectively reduced without affecting the performance of PPS. Simultaneously, the use of polymer A, which is homologous to polymer B, improves the compatibility between the island and sea components, thereby reducing the risk of island delamination and improving the productivity of the PPS island-island composite fiber. Furthermore, during the weight reduction treatment of the PPS island-island composite fiber of this invention, the island component is dissolved, and the homologous polymer B distributed on the surface of the island component is also dissolved, forming linear grooves on the surface of the PPS fiber. These grooves increase the specific surface area of ​​the PPS fiber obtained by this invention. Compared with ordinary PPS fibers of the same type with smooth surfaces, the ratio of their specific surface areas reaches more than 1.05, improving its filtration, hydrogen production, and other performance characteristics.

[0023] The polymer A described in this invention is a polyester-based polymer, polyamide-based polymer, or polyolefin-based polymer with high flowability. Specific examples include polyethylene terephthalate or its modified polymers, polypropylene terephthalate or its modified polymers, polybutylene terephthalate or its modified polymers, polyamide 6 or its modified polymers, polyamide 66 or its modified polymers, polyamide 56 or its modified polymers, polyethylene or its modified polymers, polypropylene or its modified polymers, polybutene or its modified polymers, etc. The modification mainly refers to easy-to-dissolve modification, such as copolymerization of aromatic sulfonate compounds, polyether compounds, etc.

[0024] Polymer B and polymer A are homologous polymers, meaning they both belong to the polyester family, the polyamide family, or the polyolefin family. The components of polymer B and polymer A do not need to be completely identical. For example, when polymer A is polyethylene terephthalate, polymer B can be any one of polyethylene terephthalate or its modified polymers, polyethylene terephthalate or its modified polymers, or polyethylene terephthalate or its modified polymers.

[0025] Polyphenylene sulfide (PPS) exhibits excellent heat resistance and chemical corrosion resistance, making it difficult to reduce its weight. When polymers A and B are polyester-based polymers, sodium hydroxide solution can be used to reduce the weight of PPS island-island composite fibers. When polymers A and B are polyamide-based polymers, formic acid solution can be used. When polymers A and B are polyolefin-based polymers, toluene can be used. Considering the cost and ease of operation of the weight reduction process, polyester-based polymers are preferred for polymers A and B, and easily soluble modified polyester-based polymers are further preferred.

[0026] The cross-sectional shape of the island component in this invention is not particularly limited and can be circular, triangular, quadrilateral or other irregular shapes.

[0027] The average diameter of the island components on the cross-section of the composite fiber is 0.100–10.000 μm. If the average diameter of the island components is greater than 10.000 μm, the specific surface area of ​​the resulting polyphenylene sulfide fiber is inherently low, and the number of grooves formed after weight reduction is also small. Therefore, the effect of increasing the specific surface area of ​​the polyphenylene sulfide fiber is poor, and it can hardly enhance the filtration and other properties. If the average diameter of the island components is less than 0.100 μm, the design requirements for the spinneret will be significantly increased, leading to a substantial increase in manufacturing costs. At the same time, the specific surface area of ​​the fiber at this size is already large enough, and further forming grooves is more likely to create structural weaknesses in the fiber, making it more prone to problems such as yarn breakage and fuzzing during use. Considering factors such as spinning continuity, the incidence of yarn breakage and drift, and the filtration and hydrogen production effects of the polyphenylene sulfide fiber after weight reduction, the average diameter of the island components on the cross-section of the composite fiber is preferably 0.100–8.000 μm.

[0028] To ensure the effectiveness of polymer B in reducing viscosity and improving compatibility, the content of polymer B in the island component is preferably 1-50 wt%. If the content of polymer B is too low, it cannot effectively reduce viscosity and lower spinning temperature, and less polymer B is exposed on the surface of the island component, failing to form good bonding points with the sea component. This leads to a deterioration in the compatibility between the sea and island components, increasing the probability of delamination. Furthermore, the grooves on the surface of the polyphenylene sulfide fiber after weight reduction tend to decrease, failing to increase the specific surface area of ​​the polyphenylene sulfide fiber. Conversely, if the content of polymer B is too high, the high-temperature resistance, corrosion resistance, and electrical properties of the reduced-weight polyphenylene sulfide fiber tend to decrease. Therefore, the content of polymer B in the island component is more preferably 2-20 wt%.

[0029] In the cross-section of the composite fiber, the area of ​​all island components preferably accounts for 50-95% of the cross-sectional area. If the area ratio of all island components is too large, it can easily lead to abnormal cross-sectional shaping of the composite fiber, and the island components tend to stick together. However, if the area ratio of all island components is too small, after the composite fiber is made into a diaphragm or filter cloth and undergoes weight reduction treatment, most of the marine components will be dissolved, and large gaps will easily form between the fibers. This will lead to a decrease in the high temperature resistance, corrosion resistance, and electrical insulation properties of the polyphenylene sulfide fiber. At the same time, excessive dissolution of marine components during the weight reduction process will cause significant waste and increase costs. To ensure that the composite fiber has a good cross-sectional morphology, improve the quality of the final fiber structure, and reduce the cost of de-margining, the area ratio of all island components is more preferably 70-90%.

[0030] The distance between the outermost island and the fiber surface on the cross-section of the composite fiber is preferably 0.10–3.00 μm. When this distance is too small, it is difficult to maintain stable and uniform control with current processing precision, which can easily lead to the exposure of polyphenylene sulfide (PPS). PPS is a non-polar polymer and has poor compatibility with fatty acid ester spinning oils commonly used in polyester, polyamide, or polyolefin polymers. Exposed PPS makes it difficult for the spinning oil to form a uniform coating on the fiber surface during melt spinning, resulting in uneven oiling of the composite fiber. In subsequent processing or use, unevenly oiled composite fibers are prone to quality problems such as poor unwinding and fluctuations in processing tension, reducing processing stability and affecting product performance. Furthermore, when this distance is too small, there is only a very thin sea between the outermost island and the fiber surface. During processing such as drafting and friction, the sea component is prone to peeling and breaking, producing defects such as fuzz, leading to problems such as reduced processability. Conversely, when this distance is too large, the sea coating layer between the outermost island and the fiber surface thickens, requiring the dissolution of more sea components during weight reduction, resulting in material waste and significantly increasing processing costs. In diaphragm applications, weaving must precede weight reduction; excessive dissolution of sea components increases the gaps between polyphenylene sulfide yarns, thereby reducing filtration efficiency. Considering the uniform coating properties of the spinning oil, processing stability, and the density of the fabric structure after weight reduction, the distance between the outermost island and the fiber surface is further preferably 0.1–2.0 μm.

[0031] In the cross-section along the fiber axis of the composite fiber, polymer B in the island component is preferably in the form of a strip, and the aspect ratio of the strip is preferably above 2.0.

[0032] The polyphenylene sulfide fiber of this invention is obtained by reducing the weight of the polyphenylene sulfide island composite fiber by removing the sea component polymer A and the polymer B located on the surface of the island component. Because the polymer B distributed on the surface of the island component is elongated, linear grooves are formed on the surface of the polyphenylene sulfide fiber, with grooves spaced approximately 400 μm apart. 2The number of linear grooves with an aspect ratio of 2.0 or higher within the specified range is more than 10. These linear grooves are formed after polymer B distributed on the island surface is dissolved during the weight reduction process. The higher the content of polymer B in the island, the more polymer B is distributed on the island surface, resulting in more, longer, and deeper linear grooves after weight reduction. When used as a filter material, this allows for the adsorption of more gas and liquid, and when used as an electrolyzer diaphragm, it provides more attachment sites for the catalyst carrier, improving the filtration and hydrogen production efficiency of polyphenylene sulfide fibers. In this invention, the linear grooves must have an aspect ratio of 2.0 or higher to increase the specific surface area. To ensure that the polyphenylene sulfide fibers achieve superior filtration and hydrogen production efficiency compared to existing technologies, each 400 μm... 2 The number of linear grooves with an aspect ratio of 2.0 or higher within the range should be more than 10.

[0033] If the depth of the linear groove is too shallow, the specific surface area of ​​the polyphenylene sulfide (PPS) fiber tends to decrease; however, if the depth is too deep, it will affect the strength of the PPS fiber itself, leading to problems such as fiber breakage and fuzzing. Considering the filtration, hydrogen production effect, and strength of the PPS fiber, the depth of the linear groove is preferably greater than 10 nm and less than 1 / 4 of the diameter of the PPS fiber.

[0034] Although polymer B distributed on the island surface will dissolve, due to the strong polarity and chemical resistance of polyphenylene sulfide (PPS), polymer B encapsulated within PPS is not easily completely removed under typical weight reduction conditions. Preferably, the content of polymer B in the PPS fiber obtained after weight reduction is below 10 wt%. If there is too much polymer B in the PPS fiber, not only will the inherent high-temperature resistance, corrosion resistance, and electrical properties of the PPS fiber tend to decrease, but the distribution of PPS in the fabric will also become discontinuous, increasing the likelihood of defects such as fuzz and poor processability.

[0035] This invention does not impose any particular limitation on the preparation method of polyphenylene sulfide island-sea composite fibers. It can be any known method for preparing island-sea composite fibers. Depending on the actual equipment and application, it can be either fully drawn yarn (FDY) or false-twisted yarn (DTY). Fully drawn yarn can be obtained by a one-step spinning and drawing method or by a two-step spinning and drawing method.

[0036] Specifically, a blend of polyphenylene sulfide (PPS) and polymer B is used as the island component, and polymer A is used as the sea component. The mixture is melt-extruded into a two-component island-type spinneret, cooled, bundled, oiled, and wound to obtain unextended filaments. These unextended filaments are then subjected to an extension process to obtain PPS island-type composite fibers. The composite fibers undergo a weight-reduction treatment to remove the sea component and polymer B from the island surfaces, resulting in PPS fibers. To balance the anti-tack effect of polymer B, improve compatibility, and enhance the overall performance of the PPS fibers after weight-reduction treatment, the polymer B content in the island component is preferably 1.0–50.0 wt%.

[0037] This invention can employ various process control methods, among which the speed of the first roller during spinning is preferably controlled below 2200 m / min. If the spinning speed is too high, the compatibility between polyphenylene sulfide and other polymers is poor. As the spinning speed increases, the interfacial tension difference between the two components further increases, easily leading to interfacial delamination, causing defects such as fuzzing, and easily causing filament drift and breakage during the spinning process. In addition, it is not conducive to the formation of a continuous and stable elongated structure of polymer B in the fiber axis, thus affecting the formation of linear grooves after weight reduction. To balance spinning stability and the controllability of the surface grooves of polyphenylene sulfide fibers after weight reduction, the speed of the first roller is more preferably below 2000 m / min.

[0038] This invention improves the melt flowability of the island component by incorporating a polymer homologous to the island component into polyphenylene sulfide (PPS) and using it as the island component. This significantly reduces the melt spinning temperature, resulting in PPS island composite fibers with good cross-sectional shape, high compatibility, and resistance to island component peeling, leading to excellent manufacturability. The PPS fibers treated with weight reduction exhibit linear grooves on their surface, a large specific surface area, and a strength reaching 2.5–6.0 cN / dtex. According to the results of nitrogen adsorption method (BET method) testing, the specific surface area ratio of the PPS fibers of this invention to that of ordinary PPS fibers with smooth surfaces of the same type reaches over 1.05, improving the filtration and hydrogen production effects of the PPS fibers.

[0039] The polyphenylene sulfide island composite fiber has a wide range of applications in the preparation of fiber structures, such as industrial high-temperature flue gas filtration materials, battery separators, and electrolytic hydrogen production separators.

[0040] The testing methods for each parameter involved in this invention are as follows:

[0041] (1) The diameter of the island component and the area ratio of the sea component to the island component.

[0042] Cross-sections of the composite fibers were cut and treated with paraffin embedding. The diameters of the island components on the cross-sections of individual fibers were then photographed and measured using a microscope (Keyence VHX-6000). For island components with triangular or other irregular shapes, their areas were measured using an area meter and then converted to the diameter of a circle of equal area. The area ratio of the sea component to the island component was calculated using a paper-cutting and weighing method. Five different cross-sections were cut, and the final result was the average of the five tests.

[0043] (2) Content of polyphenylene sulfide and polymer B in polyphenylene sulfide fiber after weight reduction

[0044] The DSC curves of the polyphenylene sulfide fiber after weight reduction treatment were obtained using a differential scanning calorimeter (manufactured by TA Instruments, model: DSC25). The composition of each component was obtained by comparing the area of ​​different thermal transition peaks in the DSC curves with the corresponding thermal transition peak area of ​​the pure polymer, and the content of each component was calculated.

[0045] (3) Strength and elongation of polyphenylene sulfide fiber

[0046] The strength and elongation of the fibers were tested according to standard GB / T14344-2008. The fiber stretching machine used in this invention was manufactured by A&D Corporation of Japan, model RTC-1225A. The final result was the average of 5 tests.

[0047] (4) The distance between the outermost island component and the fiber surface of the polyphenylene sulfide composite fiber

[0048] Cross-sections of the composite fibers were cut, treated with paraffin embedding, and then photographed and measured using a microscope (Keyence VHX-6000). The distance between the outermost island component and the fiber surface was determined in the cross-sectional image of a single fiber. Five different cross-sections were cut, and measurements were taken at least three times for each cross-section. The final result was the average of all measurements.

[0049] (5) Size and number of linear grooves on the surface of polyphenylene sulfide fibers

[0050] Take a bundle of yarn containing at least 10 polyphenylene sulfide (PPS) fibers and cut it into fiber segments with an axial length of 1 cm. Randomly lay or stack the 10 PPS fiber segments (as shown in Figure 4), with no gaps between adjacent fiber segments. Use a scanning electron microscope (Thermo Fisher Scientific, model: Apero 2C) to photograph the neatly laid fiber segments from directly above at a magnification of 5000x. According to the scale bar, select a 5μm × 5μm area filled with the laid fiber segments from the photograph. Measure the length and width of the linear grooves within this area and count the number of linear grooves with an aspect ratio greater than 2.0. 16 times this number of grooves is 400μm. 2The number of linear grooves with an inner aspect ratio greater than 2.0.

[0051] Following the above method, nine more yarn bundles were tested, and the final result was the average value.

[0052] (6) Depth of linear grooves on the surface of polyphenylene sulfide fibers

[0053] Take a bundle of at least 10 polyphenylene sulfide (PPS) fibers, wrap it with epoxy resin, and slice it at room temperature. The slice thickness should be 70-150 nm. Use a transmission electron microscope (TEM, JEOL2010, manufactured by Nippon Electron Ltd.) to photograph the cross-section of the yarn and measure the depth of the grooves. Take the maximum depth as the result. Test 10 linear grooves with an aspect ratio greater than 2.0 and take the average value.

[0054] (7) Spinning properties

[0055] The number of times filament drift and breakage occur during the spinning process is statistically analyzed. When the number of filament drift and breakage is less than 1 time / t, the spinning performance is judged as 0; when the number of filament drift and breakage is 2 to 3 times / t, the spinning performance is judged as Δ; and when the number of filament drift and breakage is more than 4 times / t, the spinning performance is judged as ×.

[0056] (8) The effect of increasing the specific surface area of ​​polyphenylene sulfide fiber

[0057] 0.5g of the polyphenylene sulfide (PPS) fiber of this invention was pretreated by drying and degassing (vacuum drying at 150°C for 5 hours) to remove surface-adsorbed impurities and moisture. The pretreated PPS fiber was then placed in a nitrogen adsorption analyzer (manufactured by McMurray Instruments (Shanghai) Co., Ltd., model ASAP 2460). At liquid nitrogen temperature (77K), nitrogen gas at different pressures was introduced into the sample tube, and the amount of nitrogen adsorbed on the surface of the PPS fiber was measured. By measuring the amount of nitrogen adsorbed on the surface of the PPS fiber under different relative pressures, the specific surface area S1 of the PPS fiber can be calculated using the BET equation.

[0058] Take another 0.5g of ordinary polyphenylene sulfide fiber of the same variety (same fineness and F number) with a smooth surface, and test its specific surface area S2 using the same method. When S1 / S2 is greater than 1.10, the increase in specific surface area of ​​polyphenylene sulfide fiber is 0; when S1 / S2 is between 1.05 and 1.10, the increase in specific surface area of ​​polyphenylene sulfide fiber is △; when S1 / S2 is less than 1.05, the increase in specific surface area of ​​polyphenylene sulfide fiber is ×.

[0059] The present invention will now be described in detail with reference to the embodiments.

[0060] Example 1

[0061] Easily soluble polyester was used as the sea component. 5.0 wt% polyester and 95.0 wt% polyphenylene sulfide (PPS) were blended and granulated, and the resulting particles were used as the island component. Both the sea and island components were dried to a moisture content of less than 100 ppm and fed into a spinning machine. The yarn was spun through a 37-island composite spinneret at a spinning temperature of 300℃ and a first roller speed of 1500 m / min to obtain unextended PPS island composite yarn. After extension processing, PPS island composite fiber was obtained, with the fiber type being 56T-24F. The PPS island composite fiber was then subjected to desea treatment to obtain PPS fiber. Specific formulations and properties are shown in Table 1.

[0062] Examples 2-17

[0063] By changing the composition and content of the sea element, the area ratio of the island element, the type of composite fiber, the diameter of the island element, and the distance between the outermost island and the fiber surface, the preparation method is the same as in Example 1, and polyphenylene sulfide island composite fibers and polyphenylene sulfide fibers are prepared. Specific formulations and properties are shown in Tables 1-2.

[0064] Example 18

[0065] Modified high-temperature resistant polyethylene was used as the sea component. 10.0 wt% polyethylene and 90.0 wt% polyphenylene sulfide were blended and granulated, and the resulting particles were used as the island component. Both the sea and island components were dried to a moisture content of less than 100 ppm and fed into a spinning machine. The fibers were spun through a 37-island composite spinneret at a spinning temperature of 290℃ using a one-step stretching process. The first roller speed was 1500 m / min, and the second roller speed was 4500 m / min, yielding polyphenylene sulfide island-island composite fibers of type 56T-24F. The polyphenylene sulfide island-island composite fibers were then subjected to de-sea treatment to obtain polyphenylene sulfide fibers. Specific formulations and properties are shown in Table 2.

[0066] Comparative Example 1

[0067] The island component was changed to pure polyphenylene sulfide, and the preparation method was the same as in Example 1. The specific formulation and properties are shown in Table 2.

[0068] Because polyphenylene sulfide (PPS) is spun at high temperatures, the polyester component, being seaweed, decomposes at these temperatures, producing a large amount of small-molecule smoke that adheres to the spinneret surface, causing problems such as filament drift and breakage, resulting in poor spinnability. Furthermore, the surface of PPS fibers after seaweed removal is smooth, failing to increase specific surface area, thus leading to poor filtration and hydrogen production performance.

[0069] Comparative Example 2

[0070] Pure polyphenylene sulfide (PPS) was spun separately, dried, and fed into a spinning machine at a spinning temperature of 330°C. The spinning was performed through a single-component spinneret at a take-up speed of 1500 m / min to obtain unextended PPS yarn. After a stretching process, extended PPS yarn was obtained, resulting in PPS fiber with a single filament fineness of 2.33 dtex. Specific formulations and properties are shown in Table 2.

[0071] This method requires high spinning temperatures and sophisticated equipment, and it cannot produce polyphenylene sulfide fibers with small monofilament fineness. Furthermore, the smooth surface of polyphenylene sulfide fibers does not increase the specific surface area, resulting in poor performance in filtration, hydrogen production, and other applications.

[0072] Comparative Example 3

[0073] The polymer B in the island component was changed to polyamide, and the preparation method was the same as in Example 1. The specific formulation and properties are shown in Table 2.

[0074] Due to the poor compatibility of easily soluble polyesters and polyamides, the interfacial bonding of polyphenylene sulfide, polyester, and polyamide polymers is poor during melt spinning, resulting in poor spinnability. Furthermore, the polyphenylene sulfide fibers obtained after desiccant treatment have fewer grooves on their surface, making it difficult to effectively increase the specific surface area, and thus their performance improvement in applications such as filtration and hydrogen production is not significant.

[0075] Comparative Example 4

[0076] The design of the spinneret, fiber type, number of islands, etc. were changed to make the island component diameter 21.383μm. The preparation method is the same as in Example 14. The specific formula and physical properties are shown in Table 2.

[0077] Because the island components have excessively large diameters, the specific surface area of ​​the polyphenylene sulfide fibers obtained after the weight reduction treatment is inherently low, and the number of linear grooves formed on the fiber surface is limited, making it difficult to effectively increase the specific surface area. At the same time, the gaps between the monofilaments after weight reduction are relatively large, resulting in insufficient structural compactness when preparing fiber structures such as filter membranes, leading to poor filtration performance.

[0078] Comparative Example 5

[0079] The spinneret design and number of islands were modified to make the island component diameter 0.067 μm. The preparation method was the same as in Example 15. The specific formula and physical properties are shown in Table 2.

[0080] Because the island components have a very small diameter, the requirements for the spinneret are high, resulting in poor spinning performance.

[0081]

[0082]

Claims

1. Polyphenylene sulfide island-sea composite fiber, characterized in that: The polyphenylene sulfide island composite fiber has an island component of polymer A and an island component of a blend of polyphenylene sulfide and polymer B; polymer A is a polyester polymer, polyamide polymer, or polyolefin polymer, and polymer B is a homologous polymer to polymer A; the average diameter of the island component in the cross-section of the composite fiber is 0.100–10.000 μm.

2. The polyphenylene sulfide island-sea composite fiber according to claim 1, characterized in that: The polymer B accounts for 1.0 to 50.0 wt% of the island component.

3. The polyphenylene sulfide island-sea composite fiber according to claim 1 or 2, characterized in that: In the cross-section of the composite fiber, the area of ​​all island components accounts for 50-95% of the cross-sectional area.

4. The polyphenylene sulfide island-sea composite fiber according to claim 1 or 2, characterized in that: On the cross-section of the composite fiber, the distance between the outermost island and the fiber surface is 0.10 to 3.00 μm.

5. The polyphenylene sulfide island-sea composite fiber according to claim 1 or 2, characterized in that: In the cross-section along the fiber axis of the composite fiber, polymer B in the island component is in the form of long strips with an aspect ratio of 2.0 or higher.

6. Polyphenylene sulfide fiber, obtained by reducing the amount of polyphenylene sulfide island-island composite fiber as described in claim 1 and removing the marine components, characterized in that: The surface of the polyphenylene sulfide fiber has linear grooves, and every 400 μm 2 The number of linear grooves with an aspect ratio of 2.0 or higher within the range is more than 10.

7. The polyphenylene sulfide fiber according to claim 6, characterized in that: The depth of the linear trench is greater than 10 nm.

8. The polyphenylene sulfide fiber according to claim 6, characterized in that: The content of polymer B in the polyphenylene sulfide fiber is less than 10.0 wt%.

9. The polyphenylene sulfide fiber according to claim 6, 7 or 8, characterized in that: The strength of the polyphenylene sulfide fiber is 2.5 to 6.0 cN / dtex.

10. The method for preparing the polyphenylene sulfide island-sea composite fiber according to claim 1, characterized in that: Polymer A is used as the sea component, and a blend of polyphenylene sulfide and polymer B is used as the island component. The island-island composite fiber is obtained by island-island composite spinning. Polymer A is a polyester polymer, a polyamide polymer, or a polyolefin polymer, and polymer B is a homologous polymer to polymer A.

11. The method for preparing polyphenylene sulfide island-sea composite fiber according to claim 10, characterized in that: The content of polymer B in the island component is 1.0 to 50.0 wt%.

12. The method for preparing polyphenylene sulfide island-sea composite fiber according to claim 10, characterized in that: During the spinning process, the speed of the first roller is below 2200 m / min.

13. The application of the polyphenylene sulfide island composite fiber according to claim 1 in the preparation of fiber structures.

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