Antistatic synthetic fiber

Abstract

To obtain an antistatic synthetic fiber with excellent spinning operability and sufficient antistatic performance and lightfastness, using an antistatic agent other than polyalkylene glycol or a resin composition mainly composed of polyalkylene glycol. [Solution] An antistatic synthetic fiber containing potassium trifluoromethanesulfonate. Preferably, the antistatic synthetic fiber contains a resin composition made of a copolymer resin containing potassium trifluoromethanesulfonate and polyamide 12, polyethylene glycol, and sebaciic acid as repeating units, and a synthetic resin.

Description

[Technical Field]

[0001] The present invention relates to an antistatic fiber. [Background Art]

[0002] Polyester fibers are used in a wide range of applications because they are low in cost and excellent in mechanical properties. However, polyester is inherently hydrophobic and has high electrical resistance, so it tends to easily generate static electricity. Various methods for imparting antistatic properties to polyester fibers have been proposed to date to solve this drawback. As a method for imparting antistatic properties, addition of a hydrophilic compound to polyester can be mentioned. A typical example thereof is polyalkylene glycol, and polyester fibers added with polyalkylene glycol or a resin composition containing polyalkylene glycol as a main component have been proposed. Patent Document 1 discloses an antistatic polyester fiber containing 6 to 16% by weight of polyethylene glycol having a weight average molecular weight of 15,000 to 50,000 and a molecular weight distribution (Mw / Mn) of 1.7 or more, preferably 1.8 to 2.0, wherein unreacted polyethylene glycol accounts for 40% by weight or less of the total contained polyethylene glycol. In addition, a method of imparting antistatic properties to the fiber surface by post-processing has also been proposed. Patent Document 2 proposes a woven or knitted fabric made of fibers to which conductivity is imparted by adhering a conductive polymer to the surface layer of fibers having a single yarn fineness of 1.0 dtex to 5.0 dtex. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2016-148132 [Patent Document 2] Japanese Unexamined Patent Publication No. 2007-113132 [Summary of the Invention] [Problems to be Solved by the Invention]

[0004] However, the fibers described in Patent Document 1 have insufficient antistatic performance because polyethylene glycol is dispersed throughout the entire fiber. Increasing the antistatic agent content to improve antistatic performance would increase costs and worsen spinning operability. Furthermore, because polyalkylene glycol has low viscosity and is difficult to mix with the resin that forms the fibers, a method of injecting it into the nozzle using a press-in machine is preferred. In this method, polyalkylene glycol is injected using a press-in machine before reaching the metering gear pump, mixed with polyester in a static mixer, and the mixture is measured by a metering gear pump and discharged from the nozzle. However, this method has problems such as the complexity of the equipment, high management costs, and unstable injection volume resulting in poor spinning operation. In addition, because polyalkylene glycol has low viscosity, it easily bleeds out onto the fiber surface, and when washed, the agent leaches out, reducing the antistatic performance. For the reasons stated above, there is a need for antistatic fibers that use antistatic agents other than polyalkylene glycol or resin compositions mainly composed of polyalkylene glycol. The fibers described in Patent Document 2 have a conductive polymer attached to the surface layer of the fibers to provide antistatic properties. However, after several washes, the polymer peels off, causing a decrease in antistatic and conductive properties. Therefore, the present invention aims to obtain an antistatic fiber that can contain an antistatic component in the fiber by using an antistatic agent other than polyalkylene glycol or a resin composition mainly composed of polyalkylene glycol. Another objective is to obtain an antistatic synthetic fiber with excellent spinning operability and sufficient antistatic performance and lightfastness by using an antistatic agent other than polyalkylene glycol or a resin composition mainly composed of polyalkylene glycol. [Means for solving the problem]

[0005] As a result of diligent research, the inventors of the present invention have discovered that by using a synthetic fiber containing potassium trifluoromethanesulfonate, it is possible to obtain an antistatic fiber containing an antistatic component in the fiber using a resin composition other than polyalkylene glycol, and thus arrived at the present invention. In particular, by using a resin composition composed of a copolymer of potassium trifluoromethanesulfonate, polyamide 12, polyethylene glycol, and sebaciic acid, the antistatic agent can be uniformly dispersed within the fibers, resulting in a fiber that exhibits sufficient antistatic performance, lightfastness, and good operability while keeping costs down. In other words, to achieve the above objective, the present invention employs the following configuration. Firstly, it is an antistatic synthetic fiber containing potassium trifluoromethanesulfonate. Secondly, the present invention relates to an antistatic synthetic fiber containing a resin composition made of a copolymer resin comprising potassium trifluoromethanesulfonate and polyamide 12, polyethylene glycol, and sebacic acid as repeating units, and a synthetic resin. Thirdly, the resin composition contains 1 to 10% by mass of potassium trifluoromethanesulfonate, which is the antistatic synthetic fiber. Fourth and fifth, the above-mentioned antistatic synthetic fiber further contains polymethyl methacrylate or polyethylene terephthalate in the resin composition. Sixth, the synthetic fiber is an antistatic synthetic fiber with a ratio (mass ratio) of synthetic resin to resin composition of 7:1 to 100:1. Seventh, the above-mentioned antistatic synthetic fiber is one in which the main resin constituting the synthetic fiber is polyester. [Effects of the Invention]

[0006] According to the present invention, an antistatic fiber can be obtained that has a component other than polyalkylene glycol as its main component. In particular, an antistatic fiber can be obtained by using a resin composition in which polyamide 12 is the main component, along with polyalkylene glycol and sebaciic acid, and combining it with potassium trifluoromethanesulfonate, which is an antistatic component. Furthermore, because it offers excellent spinning operability and allows for uniform dispersion of the antistatic agent within the fiber while keeping production costs down, it is possible to obtain antistatic synthetic fibers with good antistatic properties and excellent lightfastness. [Modes for carrying out the invention]

[0007] The present invention will be described in detail below. The antistatic synthetic fiber of the present invention contains potassium trifluoromethanesulfonate. Specifically, the antistatic synthetic fiber of the present invention is preferably an antistatic synthetic fiber obtained by blending a resin composition containing a polyamide copolymer resin and potassium trifluoromethanesulfonate with a thermoplastic resin.

[0008] In the present invention, potassium trifluoromethanesulfonate is preferably used as an antistatic component of the resin composition. The concentration (content) of potassium trifluoromethanesulfonate added to the resin composition is preferably 1 to 10% by mass relative to the resin composition, as this facilitates the development of antistatic properties. More preferably, it is 1.2 to 5% by mass. Below 1% by mass, antistatic properties are difficult to develop, and above 10% by mass, there is a tendency for decreased elongation strength and poor lightfastness.

[0009] The following will provide a more detailed explanation of the case in which the above resin composition is used as an antistatic component. The antistatic synthetic fiber of the present invention is preferably a fiber obtained by blending a resin composition containing potassium trifluoromethanesulfonate with a main synthetic resin.

[0010] Polyester is a preferred example of the synthetic resin mentioned above. Specific examples of polyester include polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polytrimethylene terephthalate, polybutylene naphthalate, and copolymerized polyesters made from these.

[0011] The resin composition of the present invention comprises potassium trifluoromethanesulfonate and a thermoplastic resin.

[0012] The thermoplastic resin used in the resin composition of the present invention preferably includes a copolymer resin. The copolymer resin is preferably a polyamide copolymer resin. Specifically, the copolymer resin is preferably a copolymer of polyamide 12, polyethylene glycol, and sebacic acid, from the viewpoint of easily assisting the antistatic properties of potassium trifluoromethanesulfonate. The polyethylene glycol is preferably PEG1540 with a molecular weight in the range of 1200 to 1800, and is particularly preferably a copolymer of polyamide 12, PEG1540, and sebacic acid.

[0013] The above copolymer resin preferably contains polyamide 12 as the main component and polyethylene glycol and sebacic acid as minor components. Specifically, the composition ratio is preferably 60 to 90 mol% of the total copolymer resin for polyamide 12 and 5 to 20 mol% each for the minor components. Specifically, examples include polyamide 12:polyethylene glycol:sebacic acid = 60:20:20, 80:10:10, and 90:5:5. Within this range, the antistatic properties of potassium trifluoromethanesulfonate can be exhibited particularly efficiently. When using a composition ratio within this range, it is particularly preferable to use PEG1540 for polyethylene glycol. Particularly preferred embodiments include polyamide 12:polyethylene glycol:sebacic acid in ratios of 60:20:20, 80:10:10, and 90:5:5.

[0014] The thermoplastic resin in the resin composition of the present invention may be a mixture of the above copolymer resin with other resins. Examples of other resins include polymethyl methacrylate (PMMA) and polyethylene terephthalate (PET), which may be included to enhance affinity with the synthetic resin being blended. In terms of the amount (content) of the other resin added, in the case of PMMA, an amount (content) of less than 30% by mass relative to the resin composition is preferred, in order to avoid impairing the antistatic properties. In the case of PET, an amount (content) of 40% or less relative to the resin composition is preferred.

[0015] From the perspective of the balance between antistatic property and light fastness, the mixing ratio of the above synthetic resin to the above resin composition is preferably synthetic resin:resin composition = 7:1 to 100:1, more preferably synthetic resin:resin composition = 10:1 to 100:1, and still more preferably 20:1 to 60:1. When the content of the synthetic resin is less than 7:1, sufficient antistatic property can be obtained, but the light fastness tends to deteriorate. When the content of the synthetic resin is more than 100:1, the antistatic property tends to decrease.

[0016] The antistatic synthetic fiber of the present invention may be a single fiber composed of the above synthetic resin and the above resin composition, or may be a conjugate fiber using the above synthetic resin and the above resin composition as a part of components of the conjugate fiber. In the case of a conjugate fiber, it is preferable that the layer containing the resin composition is a layer on the fiber surface. The proportion of the layer added with the resin composition exposed on the surface is preferably 40% or more. When the proportion is less than 40%, sufficient antistatic performance tends not to be exhibited.

[0017] In the case of polyester, the moisture content of the synthetic resin and the resin composition used in the present invention is preferably 50 ppm or less from the viewpoint of spinning operability. It is preferable to lower the moisture content as the single filament fineness becomes smaller.

[0018] The antistatic synthetic fiber of the present invention may contain commonly used additives, lubricants, matting agents, antioxidants, fluorescent brighteners, antistatic agents, light stabilizers and the like, as long as the effects of the present invention are not impaired.

[0019] The total fineness of the antistatic synthetic fiber of the present invention is preferably 10 dtex or more. When the total fineness is 10 dtex or more, fiberization is facilitated.

[0020] The breaking strength of the antistatic synthetic fiber of the present invention is preferably 3.0 cN / dtex or more, more preferably 3.5 cN / dtex or more, from the viewpoint of avoiding yarn breakage during weaving and knitting processing and maintaining good process passability in post-processing.

[0021] The break elongation of the antistatic synthetic fiber of the present invention is preferably 28-45%, more preferably 30-37%, from the standpoint of preventing yarn breakage during weaving and knitting processes and ensuring good passability through post-processing steps.

[0022] Methods for producing the antistatic synthetic fibers of the present invention include, for example, the conveyor belt method, the POY method, and the SPD method. However, from the viewpoint of labor saving and productivity, the SPD method (direct spinning and drawing method) is preferred, and if a decorative yarn is to be obtained, it is preferable to adopt the POY-false twist method (a method in which a semi-drawn yarn is false-twisted using the POY method).

[0023] In the SPD method, the spinning temperature is preferably 280°C or higher. More preferably, the spinning temperature is 290°C or higher. The upper limit is preferably around 300°C.

[0024] The antistatic synthetic fiber of the present invention can be suitably used in woven fabrics, knitted fabrics, and other textiles. As a fabric using the antistatic synthetic fiber of the present invention, it is preferable that it contains 40% by mass or more of the antistatic synthetic fiber of the present invention, as this allows for sufficient antistatic properties to be exhibited. Furthermore, in the case of woven or knitted fabrics using the antistatic synthetic fibers of the present invention, it is preferable to use at least 40% by mass or more of antistatic synthetic fibers in either the warp or weft threads, as this makes it easier to protect against static electricity when worn as clothing.

[0025] The frictional voltage resistance (Method B) of the fabric using the antistatic synthetic fibers of the present invention is preferably 3kV or less, and more preferably 1kV or less, under standard conditions. For general polyester without added antistatic agents, it is usually around 5-7kV. Although the required frictional voltage resistance varies depending on the application, by using the antistatic synthetic fibers of the present invention as described above, it can be reduced to 3kV or less, making it usable as an antistatic fabric.

[0026] The lightfastness of fabrics using the antistatic synthetic fibers of the present invention should be at least grade 3, and preferably grade 4 or higher. Below grade 3, yellowing tends to occur, resulting in a poor appearance.

[0027] By using fabrics containing the antistatic synthetic fibers of the present invention as materials for clothing linings, sheets, and the like, these products can be given sufficient antistatic properties. [Examples]

[0028] The present invention will be specifically described below with reference to examples. However, the present invention is not limited to the examples described below. The physical properties were measured and evaluated as follows. A. Fineness In accordance with JIS L 1013, the sample was wound onto a measuring machine with a frame circumference of 1.125 m at a speed of 120 rotations / min, its mass was measured, and the fineness was determined. This measurement was performed five times, and the average value was calculated. B. Breaking strength, breaking elongation In accordance with JIS L 1013, measurements were taken using a Shimadzu AGS-1KNG Autograph® tensile testing machine under the conditions of a sample yarn length of 20 cm and a constant tensile speed of 20 cm / min. The breaking strength (cN / dtex) was defined as the value obtained by dividing the maximum load on the load-elongation curve by the fineness, and the elongation rate at that point was defined as the elongation at break (%). C. Spinning properties During spinning, if bobbin collection and winding were impossible, or if the yarn broke directly below the nozzle when sucked up by the suction mechanism, it was marked "×". If the yarn broke 1 or 2 times during 24 hours of operation, it was marked "△". If the yarn broke 0 times during 24 hours of operation, it was marked "〇". D. Friction withstand voltage test Under conditions of 20°C and 40% RH (or 30% RH), the test specimen is rubbed against a friction cloth (cotton or wool) while rotating, using a friction voltage measuring instrument in accordance with Method B (Friction Voltage Measurement Method) of JIS L 1094 (2014), and the voltage (V) generated during friction is measured. The voltage of the test specimen is measured 60 seconds after the start of friction. E. Lightfastness Measurements are performed using a sunshine weather meter (manufactured by Suga Test Instruments Co., Ltd.) in accordance with the ultraviolet carbon arc lamp (JIS L 0842) that emits ultraviolet light. The test specimen is placed between pieces of cardboard with a small window and mounted in the sample holder. The ultraviolet carbon arc lamp is used to illuminate the target blue scale (grade 3 blue scale for grade 3 tests, grade 4 blue scale for grade 4 tests) until it has faded to the standard color. After irradiation, the test specimen is removed, and the difference in color between the illuminated and unexposed parts is compared with the standard-faded blue scale to make a determination. F. Overall Rating The final decision is based on a comprehensive evaluation of three points: spinnability, frictional voltage, and lightfastness. A score of △ or higher is considered a pass. In this case, spinnability is rated as ○, △, or × as described above; frictional voltage is 2kV or less = ○, over 2kV to 3kV = △, over 3kV = ×; and lightfastness is 3-4 grade or higher = ○, grade 3 = △, grade 2 or lower = ×. If all three items are ○, the final score is ○. If any of the three items are excluding × and there is even one △, the final score is △; and if any of the three items are even one ×, the final score is ×.

[0029] [Example 1] As the antistatic resin composition, a copolymer resin containing 1.5% by mass of potassium trifluoromethanesulfonate was used, with polyamide 12, PEG1540, and sebacic acid in a molar ratio of 8:1:1. Polyethylene terephthalate was used as the synthetic resin. The resin composition and synthetic resin were dried in a vacuum dryer to a moisture content of 40 ppm. Polyethylene terephthalate and the resin composition were mixed in a 7.3:1 ratio and melt-spinned. The polymer was extruded using an extruder adjusted to a temperature higher than the polymer's melting point, weighed with a gear pump, and the yarn discharged from the die was passed through an oil-applying guide. An antistatic synthetic fiber of 84 dtex / 36f was obtained by direct spin-drawing (fineness 80.9 dtex, breaking strength 3.29 cN / dtex, breaking elongation 28.6%). The spinnability was evaluated as △. The obtained antistatic composite fibers were used as the weft, and 56dtex / 36f semi-dull polyethylene terephthalate fibers were used as the warp, resulting in a plain weave fabric with a warp density of 97 threads / 2.54cm and a weft density of 83 threads / 2.54cm. Subsequently, scouring, setting, dispersion dyeing, and water finishing processes were carried out to obtain an antistatic treated fabric. The resulting frictional voltage was measured to be 0.2kV, and the lightfastness was grade 2. Despite having components other than polyalkylene glycol as the main components, the antistatic synthetic fibers obtained from Example 1, as well as the processed fabrics, all exhibited low frictional voltage and high antistatic performance, resulting in sufficiently satisfactory antistatic performance.

[0030] [Examples 2-6] Except for the mixing ratio of polyethylene terephthalate, a synthetic resin, and the resin composition being as shown in Table 1, an antistatic synthetic fiber and an antistatic processed fabric were obtained in the same manner as in Example 1.

[0031] [Comparative Example 1] Synthetic fibers and processed fabrics were obtained in the same manner as in Example 1, except that an antistatic resin composition was not added.

[0032] [Comparative Example 2] Synthetic fibers and processed fabrics were obtained in the same manner as in Example 5, except that potassium trifluoromethanesulfonate was not added.

[0033] [Example 7] Except for setting the copolymerization ratio of the antistatic resin composition (polyamide 12:PEG1540:sebacic acid) to 6:2:2, an antistatic synthetic fiber and an antistatic processed fabric were obtained in the same manner as in Example 5.

[0034] [Examples 8 and 9] Antistatic synthetic fibers and antistatic treated fabrics were obtained in the same manner as in Example 5, except that the resin compositions contained 5% by mass and 10% by mass of potassium trifluoromethanesulfonate relative to the copolymer resin.

[0035] [Example 10] As the antistatic resin composition, a copolymer resin containing 1.5% by mass of potassium trifluoromethanesulfonate was used, with polyamide 12, PEG1540, and sebacic acid each in a ratio of 8:1:1. Semi-dull polyethylene terephthalate was prepared as the synthetic resin. The resin composition and polyethylene terephthalate were dried to a moisture content of 40 ppm. As the sheath component, the resin composition and polyethylene terephthalate were prepared and mixed in a 39:1 ratio using a stirrer, and polyethylene terephthalate was used as the core component, and melt spinning was performed. The polymers were extruded using an extruder adjusted to a temperature higher than the melting point of each polymer, metered with a gear pump, and then assembled in a die. The extruded yarn was passed through an oil-applying guide, and an antistatic synthetic fiber of 84 dtex / 36 f was obtained by direct spinning and drawing. Next, an antistatic processed fabric was obtained in the same manner as in Example 5.

[0036] [Example 11] Antistatic synthetic fibers and antistatic processed fabrics were obtained in the same manner as in Example 5, except that an antistatic resin composition containing a blend of a copolymer resin and potassium trifluoromethanesulfonate with PMMA was used. The mixing ratio (mass ratio) was copolymer resin:PMMA = 80:20.

[0037] [Example 12] Synthetic fibers and antistatic fabrics were obtained in the same manner as in Example 5, except that the antistatic resin composition used contained a blend of PET in addition to the copolymer resin and potassium trifluoromethanesulfonate. The mixing ratio (mass ratio) was copolymer resin:PET = 70:30.

[0038] [Comparative Examples 3 and 4] Synthetic fibers and processed fabrics were obtained in the same manner as in Examples 11 and 12, except that potassium trifluoromethanesulfonate was not added.

[0039] [Example 13] Except for using PBT as the synthetic resin, antistatic synthetic fibers and antistatic treated fabrics were obtained in the same manner as in Example 5.

[0040] [Comparative Example 5] Synthetic fibers and processed fabrics were obtained in the same manner as in Example 13, except that potassium trifluoromethanesulfonate was not added. The results for Examples 2-13 and Comparative Examples 1-5 are shown in Table 1.

[0041] [Table 1]

[0042] The antistatic synthetic fibers and processed fabrics obtained from Examples 2 to 13 all had a frictional voltage of 3kV or less, exhibiting high antistatic performance and a lightfastness of class 3 or higher, which was sufficiently satisfactory in terms of antistatic performance. In particular, Examples 5, 8 to 10, 12, and 13 had a frictional voltage of 2kV or less, a lightfastness of class 3-4 or higher, and furthermore, were sufficiently satisfactory in terms of antistatic performance. Comparative Example 1, lacking an antistatic resin composition, resulted in fibers and fabrics that were not antistatic. Comparative Examples 2-5 did not contain trifluorosulfonic acid in the resin composition, resulting in fibers and fabrics that did not exhibit sufficient antistatic properties, leading to fabrics that were prone to static electricity and uncomfortable to wear. [Industrial applicability]

[0043] The antistatic synthetic fiber of the present invention has good spinning properties and excellent antistatic performance, and can be suitably used as a lining when blended with polyester woven or knitted fabrics to create an antistatic fabric.

Claims

1. An antistatic synthetic fiber containing potassium trifluoromethanesulfonate.

2. An antistatic synthetic fiber containing a resin composition made of a copolymer resin containing potassium trifluoromethanesulfonate, polyamide 12, polyethylene glycol, and sebaic acid as repeating units, and a synthetic resin.

3. The antistatic synthetic fiber according to claim 2, comprising 1 to 10% by mass of potassium trifluoromethanesulfonate in a resin composition.

4. The antistatic synthetic fiber according to claim 2 or 3, further comprising polymethyl methacrylate in the resin composition.

5. The antistatic synthetic fiber according to claim 2 or 3, further comprising polyethylene terephthalate in the resin composition.

6. The antistatic synthetic fiber according to claim 2 or 3, wherein the ratio (mass ratio) of the synthetic resin to the resin composition is 7:1 to 100:

1.

7. An antistatic synthetic fiber according to any one of claims 1 to 3, wherein the main resin constituting the synthetic fiber is polyester.

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