Antistatic Island-in-the-Sea Fiber

Abstract

To obtain an antistatic sea-island fiber having good spinning operability, low cost and sufficient antistatic performance.SOLUTION: There is provided an antistatic sea-island fiber that comprises island portions comprising polyester and a sea portion comprising polyester and an antistatic agent. The fiber is composed of island portions that are not exposed on the fiber surface and the sea portion that covers the island portions. A content of the antistatic agent in the entire fiber is 2.2 to 3.3 mass%, and a content of the antistatic agent in the sea portion is 4.5 to 6.0 mass%. A ratio of an area occupied by the sea portion in a fiber cross section is 40 to 70%.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an antistatic islands-in-sea fiber. [Background technology]

[0002] Polyester fibers are used in a wide range of applications due to their low cost and excellent mechanical properties. However, polyester is inherently hydrophobic and has high electrical resistance, making polyester fibers prone to static electricity. To overcome this drawback, various methods for imparting antistatic properties to polyester fibers have been proposed. One method for imparting antistatic properties is to add a hydrophilic compound to polyester. A representative example is polyalkylene glycol, and polyester fibers have been proposed to which polyalkylene glycol or a resin composition containing polyalkylene glycol as a main component has been added. Patent Document 1 describes polyester fibers containing polyethylene glycol as an antistatic agent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-148132 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the fiber described in Patent Document 1 has polyethylene glycol dispersed throughout the fiber as an antistatic agent, and therefore has insufficient antistatic performance compared to the amount of antistatic agent contained. Increasing the amount of antistatic agent to improve antistatic performance increases costs and also deteriorates spinning operability. Furthermore, since polyalkylene glycol has a low viscosity and is difficult to mix with the resin that forms the fiber, a method of injecting it into a spinneret using a press machine is preferably used. In this method, polyalkylene glycol is injected using a press machine before reaching the metering gear pump, mixed with polyester in a static mixer, and the mixture is metered using a metering gear pump and discharged from the spinneret. This method has problems such as high management costs due to the complexity of the equipment, instability in the amount of injection, and poor spinning operability. Furthermore, since polyalkylene glycol has a low viscosity, it easily bleeds out onto the fiber surface, and washing causes the agent to come off, resulting in a decrease in antistatic performance. For the above reasons, there is a demand for antistatic fibers using antistatic agents other than polyalkylene glycols or resin compositions containing polyalkylene glycols as the main component. Therefore, an object of the present invention is to obtain an antistatic fiber that is excellent in spinning operability and has sufficient antistatic performance even when an antistatic agent other than polyalkylene glycol or a resin composition containing polyalkylene glycol as a main component is used. [Means for solving the problem]

[0005] The present inventors have conducted extensive research and found that a sea-island composite fiber containing a specific amount of antistatic agent only in the sea region can provide a fiber that exhibits sufficient antistatic performance and good operability while keeping costs down, and have completed the present invention. (1) An antistatic islands-in-sea fiber in which island portions contain polyester and a sea portion contains polyester and an antistatic agent, the antistatic islands being composed of a plurality of island portions not exposed on the fiber surface and a sea portion covering the island portions, the content of the antistatic agent in the entire fiber being 2.2 to 3.3 mass%, the content of the antistatic agent in the sea portion being 4.5 to 6.0 mass%, and the ratio of the area of ​​the sea portion to the fiber cross section being 40 to 70%.

[0006] (2) The antistatic islands-in-sea fiber according to (1), wherein the antistatic agent contains potassium trifluoromethanesulfonate.

[0007] (3) The antistatic sea-island composite fiber according to (1) or (2), having a total fineness of 10 dtex or more.

[0008] (4) The antistatic islands-in-sea fiber according to any one of (1) to (3), wherein the single yarn fineness is 1 to 10 dtex.

[0009] (5) The antistatic sea-island composite fiber according to any one of (1) to (4), wherein the number of island parts is 10 to 40. [Effects of the Invention]

[0010] According to the present invention, an antistatic sea-island composite fiber having excellent spinning operability and antistatic properties can be obtained at low cost. [Brief explanation of the drawings]

[0011] [Figure 1] An example of a fiber cross section different from the antistatic sea-island fiber of the present invention [Figure 2] An example of a fiber cross section different from the antistatic sea-island fiber of the present invention DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in detail below. The antistatic sea-island composite fiber of the present invention is composed of a plurality of island regions that are not exposed on the fiber surface and a sea region that covers the island regions.

[0013] The antistatic sea-island composite fiber of the present invention has an island portion containing polyester and a sea portion containing polyester and an antistatic agent. Since the antistatic agent is contained only in the sea portion, high antistatic performance is achieved even with a small amount of antistatic agent.

[0014] The polyester in the present invention is preferably made of at least one polymer selected from polyethylene terephthalate, polybutylene terephthalate, and poly-p-ethyleneoxybenzoate, with polyethylene terephthalate being particularly preferred.

[0015] The antistatic agent in the present invention is not particularly limited as long as it is not a polyalkylene glycol or a resin composition containing a polyalkylene glycol as a main component, but can be appropriately selected from anionic surfactants such as alkyl sulfonates, polyether block amide copolymers, and antistatic agents containing organic metal salts. Antistatic agents containing organic metal salts are particularly preferred because they do not exhibit temperature dependence in antistatic performance and can maintain fiber transparency. As antistatic agents containing organic metal salts, those containing potassium trifluoromethanesulfonate as the organic metal salt are preferred.

[0016] The content of the antistatic agent in the present invention is preferably 2.2 to 3.3% by mass in the entire fiber. If the content of the antistatic agent in the entire fiber is 2.2% by mass or more, a fiber with high antistatic performance can be obtained, and if it is 3.3% by mass or less, the spinning operability is also good. Furthermore, it is preferably 4.5 to 6.0% by mass in the sea portion. If the content of the antistatic agent in the sea portion is 4.5% by mass or more, a fiber with high antistatic performance can be obtained, and if it is 6.0% by mass or less, fiberization is possible.

[0017] The cross-sectional area of ​​the sea part of the antistatic sea-island composite fiber is preferably 40 to 70%, more preferably 50 to 67%, of the cross-sectional area of ​​the entire fiber. When it is 40 to 70%, the spinning operability is excellent and sufficient antistatic performance is obtained.

[0018] The number of islands in the antistatic sea-island composite fiber is preferably 10 to 40. If the number of islands is 10 or more, antistatic performance is easily exhibited. If the number of islands is 40 or less, the islands are less likely to fuse together during the spinning process, stabilizing spinning operability.

[0019] The total fineness of the antistatic sea-island composite fiber is preferably 10 dtex or more, which makes fiberization easier.

[0020] The antistatic sea-island composite fiber preferably has a single filament fineness of 1 to 10 dtex. A single filament fineness of 1 dtex or more allows for easy fiberization, while a single filament fineness of 10 dtex or less provides excellent antistatic performance. Furthermore, when made into fabric, it allows for the production of soft clothing.

[0021] The moisture content of the polyester and antistatic agent used in the present invention is preferably 50 ppm or less from the viewpoint of spinning operability. The finer the single yarn size, the more preferably drying is strengthened.

[0022] The breaking strength of the antistatic sea-island composite fiber is preferably 3.5 cN / dtex or more, more preferably 4.0 cN / dtex or more, to reduce yarn breakage during weaving and knitting and ensure good processability in post-processing.

[0023] The breaking elongation of the antistatic sea-island composite fiber is preferably 30% or more, more preferably 35% or more, to reduce thread breakage during weaving and knitting processes and improve processability in post-processing.

[0024] The antistatic sea-island composite fiber preferably has an initial friction electrification voltage of more than -8000 V, as measured by the following antistatic evaluation test. If the initial friction electrification voltage is more than -8000 V, the fiber can have sufficient performance as an antistatic yarn. <Antistatic evaluation test> The initial frictional electrification voltage of the sample is measured using JIS L 1094 2014 Method D (frictional electrification decay measurement method). The measurement conditions are as follows: Triboelectric charge measurement: Intec Co., Ltd. Triboelectric charge decay measurement device (EST-8) Friction cloth: wool Friction direction: Vertical Washing process: Washed Temperature and humidity: 20°C, 40%RH

[0025] The antistatic sea-island composite fiber can be produced by, for example, a combi-type method, a POY method, or an SPD method. However, the SPD method is preferred from the viewpoint of labor saving and productivity.

[0026] In the SPD method, the spinning temperature is preferably 280° C. or higher, more preferably 290° C. or higher. The upper limit of the spinning temperature is preferably about 300° C.

[0027] The fabric containing the antistatic sea-island composite fiber of the present invention can be used as a material for linings of clothing, sheets, etc., to impart antistatic properties to these products. [Example]

[0028] The present invention will be specifically described below with reference to examples, but the present invention is not limited to the examples described below. Measurement and evaluation of physical properties were carried out as follows.

[0029] <Antistatic evaluation test> The cylindrical knit fabric was scoured in an aqueous solution of 2 g / L sodium carbonate and 2 g / L Emulgen 707 at 70°C for 20 minutes, and then the initial friction withstand voltage was measured using the JIS L 1094 2014 D method (friction-charged voltage decay measurement method) described above. The measurement conditions were as described above. The antistatic properties were evaluated according to the following criteria. ◎: Initial friction charging voltage is -7000V or more 〇: Initial friction charging voltage is -8000V or more to less than -7000V ×: Initial frictional charging voltage is less than -8000V

[0030] <Measurement of breaking strength and breaking elongation> Measurements were performed using a Shimadzu AGS-1KNG Autograph (registered trademark) tensile tester with a sample length of 20 cm and a constant tensile test speed of 20 cm / min in accordance with JIS L 1013. The breaking strength (cN / dtex) was determined by dividing the maximum load on the load-elongation curve by the fineness, and the elongation at that point was determined as the breaking elongation (%).

[0031] <Spinning operability evaluation> The spinning operability was evaluated according to the following criteria. ◎: No yarn breakage after 10 hours of spinning 〇: 1-2 thread breaks in 10 hours of spinning ×: Three or more thread breaks in 10 hours of spinning

[0032] Example 1 An antistatic agent containing an organic metal salt (potassium trifluoromethanesulfonate) (IonPhase hSTAT2 manufactured by Croda Japan) was used as the antistatic agent. The polyethylene terephthalate and antistatic agent were dried in a vacuum dryer to a moisture content of 40 ppm. A chip blend of polyethylene terephthalate and antistatic agent was used for the sea portion, and polyethylene terephthalate was used for the island portion. Melt composite spinning was performed using a spinneret capable of forming a sea-island cross section consisting of island portions (19 islands) not exposed on the fiber surface and sea portions covering the island portions. The area ratio of the sea portion to the fiber cross section was set to 50%, the antistatic agent content in the sea portion was set to 5% by mass, and the antistatic agent content in the entire fiber was set to 2.5% by mass. Polyethylene terephthalate and a chip blend of polyethylene terephthalate and an antistatic agent were separately extruded through two extruders adjusted to 280°C, metered by gear pumps, and then met in the spinnerets. The extruded yarn was passed through an oil application guide, passed through a first godet roller set to a speed of 980 m / min and a temperature of 83°C, and then through a second godet roller set to a speed of 3600 m / min and a temperature of 135°C, and continuously drawn to a breaking elongation of 20-40%. The yarn was then taken up on a winder set to a speed of 3570 m / min to give an antistatic sea-island composite fiber of 33 dtex / 12 f. The breaking strength and breaking elongation of the resulting antistatic sea-island composite fiber were measured. Two antistatic sea-island composite multifilaments were combined and cylindrically knitted (32 gauge) on a cylindrical knitting machine, and the resulting cylindrically knitted fabric was used to evaluate antistatic properties.

[0033] Example 2 An antistatic sea-island composite fiber was produced in the same manner as in Example 1, except that the content of the antistatic agent in the sea region was 6.0% by mass and the content of the antistatic agent in the entire fiber was 3.0% by mass. The breaking strength and breaking elongation of the produced antistatic sea-island composite fiber were measured. Further, a cylindrical knitted fabric was produced in the same manner as in Example 1 and the antistatic properties were evaluated.

[0034] Example 3 An antistatic sea-island composite fiber was produced in the same manner as in Example 1, except that the content of the antistatic agent in the sea region was 4.5% by mass and the content of the antistatic agent in the entire fiber was 2.3% by mass. The breaking strength and breaking elongation of the produced antistatic sea-island composite fiber were measured. Further, a cylindrical knitted fabric was produced in the same manner as in Example 1 and the antistatic properties were evaluated.

[0035] Example 4 An antistatic sea-island composite fiber was produced in the same manner as in Example 1, except that the area ratio of the sea portion in the fiber cross section was 67% and the content of the antistatic agent in the entire fiber was 3.3% by mass. The breaking strength and breaking elongation of the obtained antistatic sea-island composite fiber were measured. Further, a cylindrical knitted fabric was produced in the same manner as in Example 1 and the antistatic properties were evaluated.

[0036] Comparative Example 1 An antistatic fiber was obtained in the same manner as in Example 1, except that a spinneret was used so that the fiber cross section would have a core-sheath shape consisting of one core not exposed on the fiber surface and a sheath covering the core, and the sea portion of Example 1 was used as the sheath portion and the island portion was used as the core. The breaking strength and breaking elongation of the obtained antistatic fiber were measured. Further, a cylindrical knitted fabric was produced in the same manner as in Example 1 and the antistatic properties were evaluated.

[0037] Comparative Example 2 An antistatic fiber was obtained in the same manner as in Example 1, except that a chip blend of polyethylene terephthalate and an antistatic agent was spun using a spinneret that gave a fiber with a circular cross section, and the content of the antistatic agent in the entire fiber was set to 3.0 mass %. The breaking strength and breaking elongation of the obtained antistatic fiber were measured. Further, a cylindrical knitted fabric was produced in the same manner as in Example 1 and the antistatic properties were evaluated.

[0038] Comparative Example 3 An antistatic fiber having the shape shown in Fig. 1 was obtained in the same manner as in Example 1, except that a spinneret was used so that the fiber cross section had a cross section 1 / sector section 2, and the sea section of Example 1 was changed to a cross section 1 and the island section to a sector section 2. The breaking strength and breaking elongation of the obtained antistatic fiber were measured. Further, a cylindrical knitted fabric was produced in the same manner as in Example 1 and the antistatic properties were evaluated.

[0039] Comparative Example 4 An antistatic fiber having the shape shown in Fig. 2 was obtained in the same manner as in Example 1, except that a spinneret was used so that the fiber cross section would have a rice-shaped portion 3 / a sector-shaped portion 4, and the sea portion of Example 1 was changed to a rice-shaped portion 3 and the island portion to a sector-shaped portion 4. The breaking strength and breaking elongation of the obtained antistatic fiber were measured. Further, a cylindrical knitted fabric was produced in the same manner as in Example 1 and the antistatic properties were evaluated.

[0040] Comparative Example 5 An antistatic fiber was obtained in the same manner as in Example 1, except that the content of the antistatic agent in the sea portion was 4.0% by mass and the content of the antistatic agent in the entire fiber was 2.0% by mass. The breaking strength and breaking elongation of the obtained antistatic fiber were measured. Further, a cylindrical knitted fabric was produced in the same manner as in Example 1 and the antistatic properties were evaluated.

[0041] Comparative Example 6 An antistatic sea-island composite fiber was obtained in the same manner as in Example 1, except that the content of the antistatic agent in the antistatic agent-containing polyethylene terephthalate was 7.0% by mass and the content of the antistatic agent in the entire fiber was 3.5% by mass. The breaking strength and breaking elongation of the obtained antistatic sea-island composite fiber were measured. Further, a cylindrical knitted fabric was produced in the same manner as in Example 1 and the antistatic properties were evaluated.

[0042] Comparative Example 7 An antistatic sea-island composite fiber was produced in the same manner as in Example 1, except that the area ratio of the sea portion in the fiber cross section was 33% and the content of the antistatic agent in the entire fiber was 1.7% by mass. The breaking strength and breaking elongation of the obtained antistatic sea-island composite fiber were measured. Further, a cylindrical knitted fabric was produced in the same manner as in Example 1 and the antistatic properties were evaluated. These results are shown in Table 1.

[0043] [Table 1]

[0044] The antistatic sea-island composite fibers obtained in Examples 1 to 4 all had an initial friction electrification voltage of -7000V or more, and exhibited high and satisfactory antistatic performance. [Industrial Applicability]

[0045] The antistatic sea-island composite fiber of the present invention has good spinning operability and excellent antistatic performance, and can be suitably used for the lining when mixed with polyester woven or knitted fabrics to produce antistatic fabrics. [Explanation of symbols]

[0046] 1 Cruciform part 2 Fan-shaped section 3 American-shaped part 4 Fan-shaped section

Claims

1. An antistatic sea-island fiber, wherein island portions contain polyester and a sea portion contains polyester and an antistatic agent, the antistatic sea-island fiber comprising a plurality of island portions not exposed at the fiber surface and a sea portion covering the island portions, the content of the antistatic agent in the entire fiber being 2.2 to 3.3 mass%, the content of the antistatic agent in the sea portion being 4.5 to 6.0 mass%, and the proportion of the area of ​​the sea portion in the fiber cross section being 40 to 70%.

2. 2. The antistatic islands-in-sea fiber according to claim 1, wherein the antistatic agent comprises potassium trifluoromethanesulfonate.

3. The antistatic sea-island composite fiber according to claim 1 or 2, wherein the total fineness is 10 dtex or more.

4. The antistatic sea-island composite fiber according to claim 1 or 2, wherein the single yarn fineness is 1 to 10 dtex.

5. The antistatic sea-island composite fiber according to claim 1 or 2, wherein the number of island parts is 10 to 40.

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