Dyed fabric including polyhydroxyalkanoate fibers and dyeing method for said fabric

Abstract

Provided are: a fabric that has strength sufficient for practical use as clothing or industrial materials and also has excellent color fastness while containing PHA fibers having marine biodegradability; and a dyeing method for obtaining said fabric. The present invention pertains to a dyed fabric which includes polyhydroxyalkanoate fibers including 3-hydroxybutyrate as a monomer unit and having a degree of crystallinity of 50% or more and which exhibits a K / S value of 2 or more. The present invention also pertains to a dyeing method for a fabric which includes polyhydroxyalkanoate fibers including 3-hydroxybutyrate as a monomer unit and having a degree of crystallinity of 50% or more. In the dyeing method, the temperature of a dyeing solution during dyeing is 86-120°C.

Description

Dyed fabric containing polyhydroxyalkanete fibers, and method for dyeing the fabric.

[0001] The present invention relates to a dyed fabric containing polyhydroxyalkanete fibers, and a method for dyeing the fabric.

[0002] In recent years, environmental problems caused by plastic waste have come into sharp focus, and the realization of a circular economy on a global scale is eagerly awaited. One of these problems is the release of microplastics into the environment, and among these, microplastics released into the ocean are considered a major issue because they not only destroy marine ecosystems when ingested by marine organisms, but also spread pollution as humans and wildlife ingest them. Furthermore, recent research has highlighted that approximately 30% of microplastics are derived from synthetic fibers, and a solution is needed from the entire textile industry.

[0003] The textile products mentioned above include types such as long fibers, short fibers, woven fabrics, knitted fabrics, and nonwoven fabrics. Among these, woven and knitted fabrics are widely used in filters, clothing, etc. Furthermore, there is a high possibility that microfibers will be released into the ocean via the air, soil, rivers, and wastewater during use, washing, and disposal, and there is a need to replace them with materials that decompose in the ocean.

[0004] To address the above issues, studies have been conducted to replace synthetic fibers such as polyester, acrylic, and nylon, which do not decompose in the ocean, with polysaccharides such as cellulose, which do decompose in the ocean. However, complete replacement is not possible because the single-fiber strength is lower than that of synthetic fibers, and it is not possible to create fabrics with the unique properties of synthetic fibers, such as moisture content, hygroscopicity, and moisture release, which are essential for the intended clothing.

[0005] On the other hand, from the perspective of reducing and fixing carbon dioxide emissions (carbon neutrality), polyhydroxyalkanetes (hereinafter sometimes abbreviated as "PHA"), which are aliphatic copolymer polyesters and bio-derived polymers, are attracting attention. Because PHAs have high biodegradability, especially marine biodegradability (the ability to decompose in the ocean), their use is being considered for various molded products such as fibers that detach from products and flow into the ocean, and films that are dumped into the ocean.

[0006] Among PHAs, poly-3-hydroxybutyrate (hereinafter abbreviated as P3HB) has been used in research on molding processes, but no material has yet been found that stably possesses mechanical properties that meet market demands compared to general resins. P3HB has a slow crystallization rate, and in molding processes, a long cooling time is required for solidification after heating and melting, resulting in very poor productivity. For example, in fiber formation, the take-up rate during melt spinning must be very slow. In addition, due to the slow crystallization rate, there are practical problems such as extremely poor unwinding after winding due to adhesion between fibers. Furthermore, P3HB is difficult to dye to dark colors compared to general synthetic fibers such as polyester. In addition, dyeing at high temperatures causes shrinkage of the fabric and a decrease in mechanical properties. For these reasons, it is difficult to dye to dark colors while maintaining the physical properties before dyeing.

[0007] Patent Document 1 below describes dyed PHBH fibers, fiber aggregates containing them, and methods for producing them.

[0008] Non-patent document 1 below describes a staining technique for using bio-based polymers (biologically derived, etc.).

[0009] International Publication No. 2024 / 058076

[0010] Research Report of the Textile Industry Technology Support Center, Hyogo Prefectural Industrial Technology Center, 2015, No. 47, 1-3, ISSN 1342-7709

[0011] The technology described in Patent Document 1 does not adequately consider color fastness. Furthermore, the technology described in Non-Patent Document 1 is based on studies of PHBH monofilaments, and does not adequately consider fabrics composed of multifilaments. In view of the level of prior art, the problem that the present invention aims to solve is to provide a fabric that contains marine biodegradable PHA fibers, has sufficient strength for practical use as clothing and industrial materials, and also has excellent color fastness, as well as a dyeing method for obtaining said fabric.

[0012] The inventors of this invention diligently studied and conducted numerous experiments to solve the aforementioned problem, and as a result, unexpectedly discovered that the problem could be solved by the following configuration, thus completing the present invention.

[0013] In other words, the present invention is as follows: [1] A dyed fabric comprising polyhydroxyalkanate fibers having a crystallinity of 50% or more and containing 3-hydroxybutyrate as a monomer unit, and having a K / S value of 2 or more. [2] The dyed fabric according to [1], wherein the polyhydroxyalkanate is a copolymer containing a second monomer unit, and the second monomer unit is any of 3-hydroxyvaliate, 4-hydroxybutyrate, or 3-hydroxyhexanoate. [3] The dyed fabric according to [2], wherein the copolymerization ratio of the second monomer unit is 5 mol% or less. [4] The dyed fabric according to any one of [1] to [3], wherein the crystallinity of the polyhydroxyalkanate is 55% or more and 80% or less. [5] The dyed fabric according to any one of [1] to [4], wherein the X-ray diffraction intensity ratio Iβ / Iα of the β structure and α structure of the polyhydroxyalkanate is 0 or more and 0.6 or less. [6] The dyed fabric according to any one of [1] to [5], wherein the softening point of the polyhydroxyalkanate is 140°C or higher. [7] The dyed fabric according to any one of [1] to [6], wherein the polyhydroxyalkanate is a multifilament long fiber. [8] The dyed fabric according to [7], wherein the number of filaments of the multifilament long fiber is 6 or more and 300 or less. [9] A method for dyeing a fabric containing polyhydroxyalkanate fibers having a degree of crystallinity of 50% or more and containing 3-hydroxybutyrate as a monomer unit, wherein the temperature of the dyeing solution during dyeing is 86°C or more and 120°C or less.

[10] The dyeing method according to [9], further comprising a washing step at 71°C or higher after dyeing.

[11] The dyeing method according to [9] or

[10] , wherein the temperature of the dyeing solution is 90°C or higher.

[12] The dyeing method according to any one of [9] to

[11] , wherein the dye contained in the dyeing solution is a disperse dye.

[13] The dyeing method according to any one of

[10] to

[12] , wherein the washing step is a reductive washing with a washing solution with a pH of 8 or higher.

[14] The dyeing method according to any one of [9] to

[13] , characterized in that the dyeing solution contains at least one selected from the group consisting of a dispersant, a uniforming agent, and an auxiliary dye.

[15] A dyeing method according to any one of [9] to

[14] , further comprising a washing step with a soaping agent after dyeing.

[0014] The dyed fabric of the present invention contains marine biodegradable PHA fibers, possesses sufficient strength for practical use as clothing and industrial materials, and further exhibits excellent colorfastness.

[0015] Embodiments of the present invention will be described in detail below. One embodiment of the present invention is a dyed fabric that contains polyhydroxyalkanete fibers having a crystallinity of 50% or more and containing 3-hydroxybutyrate as a monomer unit, and having a K / S value of 2 or more.

[0016] The K / S value of the dyed fabric in this embodiment is 2 or higher, preferably 4 or higher, and more preferably 5 or higher. A K / S value of 2 or higher limits the limitations on its use as clothing, making it possible to use it in various types of garments.

[0017] In this specification, the 'K / S value' can be measured by the following method: After cutting a fabric sample into 50 mm x 50 mm pieces, the color is measured using a spectrophotometer (Gretagmacbeth Color-Eye 7000A) under the conditions of a D56 light source and a viewing angle of 10 degrees. The L* value and K / S value in the CIE 1976 L*a*b* color space are determined, and the average value from 10 measurement points is calculated. The K / S value is calculated using the reflectance R at 630 nm, which is the representative wavelength absorbed by the blue dye, using the following formula: K / S = (1 - R) ２ It is calculated by / 2R. When using red and yellow dyes, the K / S values ​​should be obtained using the reflectances around 410 nm and 530 nm, respectively.

[0018] By setting the temperature of the dyeing solution to 86°C or higher during the dyeing process, as described later, the K / S value can be adjusted to 2 or higher, making it possible to obtain a fabric with a deep color and excellent color fastness.

[0019] The colorfastness grade of the dyed fabric in this embodiment, as defined in JIS L0844:2011 A-2 method "Test method for colorfastness to washing," is preferably grade 3 or higher, more preferably grade 4 or higher, and even more preferably grade 5. Similarly, the staining (cotton) grade is preferably grade 3 or higher, more preferably grade 4 or higher, and even more preferably grade 5. When both colorfastness and staining (cotton) are grade 3 or higher, colorfastness where the color of the fabric itself changes, and staining where color transfers from dark fabrics to light fabrics, become less likely to occur, reducing the limitations on its use as clothing and allowing it to be used in a variety of garments.

[0020] The dry friction grade of the dyed fabric of this embodiment, as defined in JIS L0849:2013 "Test Method for Color Fastness to Friction" using a Type II (Japan Society for the Promotion of Science) friction tester, is preferably Grade 3 or higher, more preferably Grade 4 or higher, and even more preferably Grade 5. A grade of Grade 3 or higher makes it less likely for the fabric itself to change color or for staining to occur, such as color transfer from dark fabrics to light fabrics, thus reducing the limitations on its use as clothing and allowing it to be used in a variety of garments.

[0021] The polyhydroxyalkaneate constituting the polyhydroxyalkaneate fibers contained in (or constituting) the dyed fabric of this embodiment is preferably a polyhydroxyalkaneate containing 3-hydroxybutyrate as a monomer unit, and more preferably a copolymer containing 3-hydroxybutyrate and a second monomer unit. The type of the second monomer unit is not particularly limited, but is preferably any of 3-hydroxyvariate, 4-hydroxybutyrate, or 3-hydroxyhexanoate, more preferably 3-hydroxyvariate or 4-hydroxybutyrate, and even more preferably 3-hydroxyvariate. If the second monomer unit is any of 3-hydroxyvariate, 4-hydroxybutyrate, or 3-hydroxyhexanoate, it is possible to achieve properties such as hygroscopicity, moisture permeability, and water absorption that are necessary to replace fabrics made of synthetic fibers but cannot be achieved with natural fibers, and it is also possible to have sufficient marine biodegradability, and in addition, it is possible to greatly improve moldability while maintaining the mechanical strength derived from the first monomer unit.

[0022] When the polyhydroxyalkaneate is a copolymer containing a second monomer unit, the ratio of the second monomer unit to the total monomer units (hereinafter abbreviated as the copolymerization ratio) is preferably 15 mol% or less, more preferably 10.0 mol% or less, even more preferably 6 mol% or less, particularly preferably 5.3 mol% or less, and most preferably 5% or less. A copolymerization ratio of 15 mol% or less allows for sufficient mechanical properties to be exhibited when processed into dyed fabric. The lower limit of the copolymerization ratio is preferably 1 mol% or more from the viewpoint of achieving excellent moldability and uniform dispersion of dye within the crystalline structure.

[0023] In this specification, the "copolymerization ratio" can be measured by the following method. An aliphatic copolymer polyester is dissolved in deuterated chloroform (chloroform-d, 99.8%, manufactured by Fujifilm Wako Pure Chemical Industries) to a concentration of 1.5% by mass to prepare the measurement sample. A nuclear magnetic resonance spectrometer (Bruker BioSpin AVANCE II 400) is used, with an observation frequency of 400 MHz, 64 integration cycles, a chemical shift reference of 7.26 ppm chloroform (chloroform, manufactured by Fujifilm Wako Pure Chemical Industries), and deuterated chloroform as the locking solvent, and 1H-NMR measurement is performed. When 4-hydroxybutyrate is included as the second monomer unit, the integral value of the triplet peak observed at a chemical shift of 4.1 ± 0.2 ppm is taken as A, and the integral value of the quartet peak observed at a chemical shift of 5.3 ± 0.2 ppm is taken as B. The copolymerization ratio C (mol%) is calculated using the following formula: C = (A / 2) / (A / 2 + B) × 100 [mol%]. When 3-hydroxyvaliate is included as the second monomer unit, D is the integral value of the triplet peak observed at a chemical shift of 0.88 ± 0.2 ppm, and E is the integral value of the doublet peak observed at a chemical shift of 1.25 ± 0.2 ppm. The copolymerization ratio F (mol%) is calculated using the following formula: F = (D / 3) / (D / 3 + E / 3) × 100 [mol%]. When 3-hydroxyhexanoate is included as the second monomer unit, G is the integral value of the triplet peak observed at a chemical shift of 0.90 ± 0.2 ppm, and H is the integral value of the doublet peak observed at a chemical shift of 1.30 ± 0.2 ppm. The copolymerization ratio I (mol%) is calculated using the following formula: I = (G / 3) / (G / 3 + H / 3) × 100 [mol%]. Methods for controlling the copolymerization ratio include appropriately selecting microorganisms, adjusting the composition and culture conditions of the fermentation raw materials, etc., but the control method is not particularly limited.

[0024] The X-ray diffraction intensity ratio Iβ / Iα of the β-structure to the α-structure of the polyhydroxyalkanete is preferably 0.6 or less, more preferably 0.4 or less, even more preferably 0.2 or less, and particularly preferably 0. The lower limit of the X-ray diffraction intensity ratio Iβ / Iα of the β-structure to the α-structure can be 0 or more. The β-structure referred to here is the β-type crystal structure formed by the extended chain, which has low thermodynamic stability. If the X-ray diffraction intensity ratio Iβ / Iα of the β-structure to the α-structure is 0.6 or less, the physical properties are less likely to change over time due to the disappearance of the β-structure when using dyed fabrics, thus providing excellent storage stability.

[0025] In this specification, the "X-ray diffraction intensity ratio of β-structure to α-structure Iβ / Iα" can be measured by the following method. Using an X-ray structure evaluation device (Rigaku, SmartLab) and a multidimensional pixel array detector (Rigaku, HiPix-3000), the X-ray wavelength is set to 0.1 nm, the camera length to 27 mm, and the exposure time to 30 min. The test specimen is placed perpendicular to the X-ray beam and parallel to the detector to obtain a two-dimensional diffraction pattern. When the diffraction intensity distribution in the equatorial direction of the two-dimensional diffraction pattern is measured, the diffraction intensity is composed of scattering by amorphous materials and diffraction by crystals. Diffraction by crystals includes diffraction of α-structures and β-structures, each producing diffraction at specific positions, and the diffraction intensity is proportional to the amount of crystal. Therefore, by taking the ratio of the diffraction intensity based on the α-structure to the diffraction intensity based on the β-structure, an index regarding the amount of β-structure can be obtained. However, since the intensity based on amorphous scattering interferes, it is necessary to remove the influence of the intensity based on amorphous scattering in order to determine the amount of β-structure in the crystal. Since the intensity based on amorphous scattering is observed as a broader baseline elevation than the intensity based on crystalline diffraction, the line connecting 2θ = 15° and 21°, where the influence of crystalline diffraction is minimal, is considered the intensity based on amorphous scattering, and this amount is subtracted from the diffraction intensity. In the subsequent diffraction intensity distribution, the maximum value between 2θ = 15° and 18° is taken as the diffraction intensity from the α structure (Iα), and the maximum value between 18° and 21° is taken as the diffraction intensity from the β structure (Iβ). The amount of β-type crystals can be evaluated by relatively comparing Iα and Iβ, and a larger ratio of Iβ / Iα indicates a higher concentration of β-type crystals.

[0026] The lower limit of the crystallinity of the polyhydroxyalkanete is 50% or higher, preferably 55% or higher, and more preferably 60% or higher. If the crystallinity is 50% or higher, sufficient mechanical properties for dyed fabrics are exhibited. The upper limit of the crystallinity is preferably 80% or lower, more preferably 75% or lower, and even more preferably 70% or lower. If the crystallinity is 80% or lower, the dye is fixed to the amorphous parts, so dye shedding during use is reduced.

[0027] As described above, by controlling the degree of crystallinity within an appropriate range, it is possible to achieve both mechanical properties and colorfastness. PHA has a low glass transition temperature of around 0°C and high molecular mobility, which makes it easy for dyes present in the amorphous region to detach, resulting in poor colorfastness. For fiber materials other than PHA, a generally known method for improving colorfastness is to increase the degree of orientation of the amorphous region and reduce molecular mobility. On the other hand, the present invention employs a novel technical means of improving colorfastness by increasing the crystalline region. A hypothesis based on this technical idea is that because the amount of dye incorporated into PHA is small, the amorphous region required for dyeing is limited, and by increasing the crystalline region, the amorphous region is dispersed and confined within the fiber, resulting in a structure in which the dye is less likely to detach. To achieve a crystallinity of 50% or more, as described later, the polyhydroxyalkanate should be a polyhydroxyalkanate containing 3-hydroxybutyrate as a monomer unit. In the case of a copolymer containing 3-hydroxybutyrate and a second monomer unit, it is important to keep the ratio of the second monomer unit to the total monomer units (hereinafter abbreviated as the copolymerization ratio) to 6 mol% or less. To further increase the crystallinity, the copolymerization ratio should be reduced.

[0028] In this specification, "crystallinity" can be measured by the following method. Crystallinity is measured using a differential scanning calorimeter (Perkin Elmer, DSC8500) equipped with an intracooler. The measurement atmosphere is nitrogen (20 ml / min), and the temperature is increased from -50°C to 200°C at a rate of 20°C / min, and held for 1 minute to completely melt the sample. The melting point peak appearing in the measured DSC curve (thermogram) is integrated to calculate the melting energy. If the melting energy is J (J / g), the crystallinity K (%) is calculated using the following formula. The sample should be around 1 mg, and an aluminum sample pan should be used. Indium should be used for temperature calibration. K = J / (146 × (100 - copolymerization ratio of the sample) / 100) × 100 (%)

[0029] The degree of crystal orientation of the α structure of the polyhydroxyalkanete is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more. The α structure referred to here is a lamellar crystal structure consisting of helical folding, and is a higher-order structure that greatly contributes to the mechanical strength of the molded article. If the degree of crystal orientation of the α structure is less than 80%, the crystal structure changes during heat treatment in dyeing, and the strength decreases significantly. If the degree of crystal orientation of the α structure is 80% or more, the single-fiber strength is increased, so single-fiber breakage is less likely to occur during processing into fabric, and the mechanical properties of the fabric are stable. There is no particular upper limit, but a realistic degree of crystal orientation is 99% or less.

[0030] In this specification, the "degree of crystal orientation of the α structure" can be measured by the following method. Using an X-ray structure evaluation device (Rigaku, SmartLab) and a multidimensional pixel array detector (Rigaku, HiPix-3000), the X-ray wavelength is set to 0.1 nm, the camera length to 27 mm, and the exposure time to 30 min. The test specimen is placed perpendicular to the X-ray beam and parallel to the detector to obtain a two-dimensional diffraction pattern. In the wide-angle X-ray diffraction (WAXD) measurement, a ring-shaped region containing a specific diffraction point (020 plane) in the WAXD image is selected, and all diffraction intensities with the same azimuthal angle are integrated. A one-dimensional azimuthal profile is created by plotting this intensity against the azimuthal angle. At the locations where diffraction points exist, a curve resembling a normal distribution with peaks is obtained, and its full width at half maximum (FWHM: the peak width at half the height of the peak) is measured. If the FWHM is L, the degree of orientation M [%] is calculated using the following formula: M = (180 - L) / 180 × 100 [%].

[0031] The polyhydroxyalkaneate constituting the fabric of this embodiment preferably has a softening point of 130°C or higher, more preferably 135°C or higher, even more preferably 140°C or higher, and particularly preferably 145°C or higher. If the softening point is 130°C or higher, changes in shape can be suppressed during processes such as use, washing, and drying. Furthermore, since the movement of PHA molecules is suppressed at temperatures used in daily life, the shedding of dye molecules is less likely to occur, and the colorfastness is improved.

[0032] In this specification, the "softening point" can be measured by the following method: Using a differential scanning calorimeter (PerkinElmer, DSC8500) equipped with an intracooler, the measurement atmosphere is nitrogen (20 ml / min), the temperature is increased from -50°C to 200°C at a rate of 20°C / min, and the softening point can be measured by reading the starting point of the endothermic peak.

[0033] The weight-average molecular weight of the polyhydroxyalkanete is preferably 150,000 or more, more preferably 200,000 or more, and even more preferably 250,000 or more. If the weight-average molecular weight is 150,000 or more, sufficient mechanical properties, especially strength, will be exhibited in the dyed fabric. Furthermore, from the viewpoint of dye fixation in the dyed fabric, the upper limit of the weight-average molecular weight is preferably 3,000,000 or less.

[0034] The weight-average molecular weight / number-average molecular weight ratio of the polyhydroxyalkanete is preferably 10 or less, more preferably 7 or less, and even more preferably 5 or less. If the weight-average molecular weight / number-average molecular weight ratio is 10 or less, the mechanical strength of the dyed fabric is stable. From the viewpoint of practical synthesis feasibility, the lower limit of the weight-average molecular weight / number-average molecular weight ratio is 1.1 or more.

[0035] In this specification, "weight-average molecular weight" and "number-average molecular weight" can be measured by the following method. Dissolve the polyhydroxyalkaneate in chloroform (chloroform manufactured by Fujifilm Wako Pure Chemical Industries) at a concentration of 0.1% by mass. Use a gel permeation chromatography apparatus (Tosoh HLC-8320GPC) and a guard column (Tosoh TSKgel guardcolumn SuperHZ-L) or an analytical column (Tosoh TSKgel SuperHZM-M). Set the column temperature to 40°C, the eluent to chloroform, the flow rate to 0.35 mL / min, the injection volume to 20 μL, and the detector to RI. Measure a polystyrene standard (Agilent Technologies EasiCal PS-1) and create a calibration curve using data processing software (Tosoh HLC-8320GPC Ecosec-WS). Polyhydroxyalkanete samples are measured in the same manner, and the weight-average molecular weight and number-average molecular weight are calculated from the calibration curve.

[0036] The structure of the fibers constituting the dyed fabric of the present embodiment is not particularly limited, such as monofilament yarns, multifilament yarns, and spun yarns. However, long fibers are preferred because they have high strength, can reduce surface hairiness, and can reduce environmental emissions during use when processed into a fabric. More preferably, they are multifilament long fibers. If the dyed fabric is composed of multifilament long fibers, the texture and color tone of the dyed fabric will be good.

[0037] The upper limit of the number of fibers of the multifilament fibers constituting the dyed fabric of the present embodiment is preferably 300 filaments or less, more preferably 250 filaments or less, still more preferably 200 filaments or less, and most preferably 150 filaments or less. If the number of fibers is 300 filaments or less, deterioration of the texture in the use of the dyed fabric, such as hairiness due to friction, can be suppressed. The lower limit of the number of fibers can be appropriately adjusted according to the total fineness of the fibers in the intended application, but is preferably 6 filaments or more, more preferably 11 filaments or more, and still more preferably 15 filaments or more. By setting the number of fibers to 6 filaments or more, the texture of the dyed fabric is better than that of monofilaments, and the color tone of the dyed fabric can be improved because the dye fixing property can be enhanced.

[0038] The fineness of the single filament of the fiber constituting the dyed fabric of the present embodiment is preferably 15 denier (D) or less, more preferably 10 D or less, and still more preferably 8 D or less. By setting the fineness to 15 D or less, the texture of the dyed fabric can be made soft, and the color tone of the dyed fabric can be improved because the dye fixing property can be enhanced.

[0039] In this specification, the "fineness of a single filament" can be measured by the following method. Take out 50 mg of fibers from the fabric, separate the constituent single filaments, measure their lengths, and sum them up. When the total length is Im, the fineness J denier (D) can be calculated by the following formula: J (denier) = 9000 (m) / I (m) × 0.05 (g).

[0040] The type of the dyed fabric in this embodiment is not particularly limited, but it is preferably a woven or knitted fabric, more preferably a woven or knitted fabric without raising. If it is a woven or knitted fabric, it has excellent mechanical strength and texture as a fabric. Also, if it is a non-raised fabric, there is less fiber shedding, less fiber release into the environment, and less reduction in the texture of the fabric due to fiber shedding. The weave structure in the case of a woven fabric is not limited, but a plain weave structure, a twill weave structure, a satin weave structure, and various modified structures derived therefrom can be applied. The knitting structure in the case of a knitted fabric is not limited, and there are circular knitting, warp knitting, etc. As the knitting machine, a weft knitting machine, a double circular knitting machine, a tricot knitting machine, a raschel knitting machine, etc. can be used. The knitting gauge of the knitting machine to be used is preferably 10G or more, more preferably 20G or more. If it is less than 10G, a knitted fabric having practical strength cannot be created. The upper limit is preferably 60G or less from the viewpoint of industrial continuous production.

[0041] The basis weight of the dyed fabric in this embodiment is not particularly limited, but from the viewpoint of having practical strength, it is preferably 10 g / m ２ or more, more preferably 50 g / m ２ or more, still more preferably 81 g / m ２ or more. If it is 10 g / m ２ or more, the difference in color development due to deep dyeing becomes clearer. The upper limit is preferably 500 g / m ２ or less, more preferably 400 g / m ２ or less, still more preferably 299 g / m ２ or less. Also, if it is 500 g / m ２ or less, uneven dyeing between the surface and the inside of the dyed fabric is less likely to occur, and a uniform and vivid color development is obtained.

[0042] The dyed fabric of this embodiment may be subjected to processing such as water absorption processing, water repellent processing, heat insulation processing, light shielding processing, UV cut processing, anti-transparency processing, pollen prevention processing, antibacterial processing, bacteriostatic processing, deodorant processing, heat insulation processing, heat storage processing, moisture absorption and heat generation processing, antistatic processing, anti-wrinkle processing, dyeing processing, printing processing, texture card processing, etc. for the purpose of enhancing the function of the dyed fabric according to its use.

[0043] The weight ratio of the polyhydroxyalkanoate fibers constituting the dyed fabric of the present embodiment is not particularly limited, but it is preferably 50 wt% or more, more preferably 70 wt% or more, and still more preferably 85 wt% or more. If it is 50 wt% or more, biodegradability of the entire fabric is ensured, and the environmental load when flowing out into the environment can be reduced. Also, even when using a dyeing process specific to polyhydroxyalkanoate, the influence on the dyeability of other fibers can be suppressed, so the dyeability of the fabric is maintained and the occurrence of color unevenness is also suppressed.

[0044] The polyhydroxyalkanoate fibers constituting the dyed fabric of the present embodiment can be produced by extruding the melt-extruded polyhydroxyalkanoate into a cooling medium, rapidly cooling it, and then centrifuging it at an arbitrary magnification outside the cooling medium and winding it up.

[0045] The method for synthesizing polyhydroxyalkanoate is not particularly limited, but those produced from microorganisms are preferred. As an example of a microorganism that produces polyhydroxyalkanoate, microorganisms having the ability to produce PHAs can be mentioned. For example, as a P3HB-producing bacterium, Bacillus megaterium discovered in 1925 was the first, and other natural microorganisms such as Cupriavidus necator (formerly classified: Alcaligenes eutrophus, Ralstonia eutropha), Alcaligenes latus, etc. are known. In these microorganisms, PHA accumulates in the cells. Also, genetically modified microorganisms into which various PHA synthesis-related genes have been introduced may be used, or the culture conditions including the type of substrate may be optimized.

[0046] When melt extrusion, granules containing polyhydroxyalkanates may be used without purification, or purified pelletized granules may be used. Furthermore, from the viewpoint of improving moldability during melt extrusion, plasticizers and nucleating agents may be included, and other polymers may be blended in. As for the method of melt extrusion of polyhydroxyalkanates, conventional plastic fiber melting techniques can be used. For example, this can be done by heating and melting the polyhydroxyalkanates, applying pressure, and extruding them from the extruder nozzle. As for the extrusion method, syringe extrusion or screw extrusion can be used. The temperature during melt extrusion is usually above the peak onset temperature of the melting point of the polyhydroxyalkanates measured by the DSC used, from the viewpoint of enabling extrusion and allowing sufficient stretching after extrusion.

[0047] The temperature for rapid cooling and fiberization after melt extrusion is preferably 30°C or lower, and more preferably 20°C or lower. There is no specific lower limit, but from an economic standpoint, it can usually be carried out at -200°C or higher. This rapid cooling process converts the molten polyhydroxyalkanet into highly stretchable amorphous fibers and suppresses deterioration over time during the process. The resulting fibers can be stretched and wound in a cooling solvent.

[0048] The cooling medium is not particularly limited, but examples include air, water (ice water), inert gas, and antifreeze mainly composed of ethylene glycol or propylene glycol. The cooling method is not particularly limited, but examples include filling a bath with a cooling medium and passing polyhydroxyalkanete through it, using a fluid bath, using a cooling plate, using a cooling ring, using a blower, or a combination thereof. In the present invention, rapid cooling can be performed, for example, by extruding molten polyhydroxyalkanete into a bath filled with a cooling medium at 30°C or lower, and passing it through the solvent while being wound up by rollers in the bath.

[0049] Furthermore, the obtained fibers can be adjusted to the desired fineness and further increased in mechanical strength by cold-stretching them within the cooling process to promote orientation and crystallization. Cold stretching can be performed, for example, by fixing the fibers to a stretcher, and preferably by applying tension by winding them with two winding rollers while varying the speed. The stretching ratio is preferably 4 times or more, more preferably 7 times or more, and even more preferably 10 times or more. The upper limit is not particularly limited as long as it does not cause breakage, but it can be 50 times or less. From the viewpoint of productivity, the stretching time is preferably 1 minute or less, and more preferably 30 seconds or less. There is no particular lower limit set for the stretching time, but in reality it can be done in 0.001 seconds or more. The stretching ratio can be measured by the following method. Take 10 cm of fiber immediately before stretching and 10 cm of fiber immediately after stretching. Set the obtained fibers in a loosely stretched state overnight in an atmosphere of room temperature 23°C and humidity 50% RH. Measure the weight of 10 points of the settled sample and calculate the number average. The extension ratio is calculated by dividing the value immediately before extension by the value immediately after extension.

[0050] There are no particular restrictions on the method of fabricating the obtained polyhydroxyalkanet-containing fibers, but in the case of woven or knitted fabrics, general looms and knitting machines can be used. Furthermore, it is preferable to apply an oil to reduce friction during the fabrication process and prevent fiber breakage. There are no particular restrictions on the method of applying the oil; it can be applied by installing a touch roll or oiling guide for applying the oil during the spinning process, or it can be applied while rewinding the yarn after spinning.

[0051] The resulting fabric may be scouring to remove oils and impurities. The scouring method is not particularly limited, but for example, it can be carried out by immersing the fabric in an aqueous dispersion containing about 0.01% to 1% of a nonionic surfactant such as Tween20 (registered trademark). Other ionic surfactants or alkalis can also be used.

[0052] The dimensional stability of the dyed fabric of this embodiment can be enhanced by heat treatment during the process, such as during spinning, after spinning, or when the fabric is made. There are no particular restrictions on the method of heat treatment; dry heat treatment or wet heat treatment may be performed to improve heat treatment efficiency. During spinning, heat treatment can be performed by arranging a hot bath, heating rollers, tunnel-type drying oven, etc. After spinning, the fibers after winding can be left to heat-treat in a dryer or constant-temperature oven. After fabrication, it is possible to leave the sample in a dryer, or it can be performed by winding it back while applying tension using a machine such as a pin tenter. The heat treatment temperature is preferably 71°C or higher, more preferably 80°C or higher, even more preferably 90°C or higher, and particularly preferably 100°C or higher. The upper limit of the temperature is preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 125°C or lower, from the viewpoint of preventing softening and melting of the fibers. Although the β-structure of polyhydroxyalkanetes has low thermal stability, treating them at temperatures above 71°C eliminates this thermally unstable β-structure beforehand, thereby suppressing dimensional changes and changes in physical properties over time during storage.

[0053] Another embodiment of the present invention is a method for dyeing a fabric containing polyhydroxyalkanate fibers containing 3-hydroxybutyrate as monomer units, wherein the temperature of the dyeing solution during dyeing is 86°C or higher and 120°C or lower. The lower limit of the dyeing solution temperature during dyeing is 86°C or higher, preferably 90°C or higher, and more preferably 95°C or higher. By setting the dyeing temperature to 86°C or higher, a darker dye can be achieved. If the dyeing temperature is 85°C or lower, it does not reach the temperature at which monomolecularization of the dye becomes active, and monomolecularization of the dye does not proceed sufficiently, resulting in a low effective dye concentration in the dye bath and making it impossible to dye the fabric darkly. Furthermore, the upper limit of the dyeing temperature is preferably 120°C or lower, more preferably 150°C or lower, and even more preferably 110°C or lower. By setting the upper limit of the dyeing temperature to 120°C or lower, it is possible to suppress the deterioration of the texture of the dyed fabric due to welding of polyhydroxyalkanate fibers to each other, and to suppress the deterioration of strength due to changes in crystal structure. Furthermore, dyeing may be performed under pressure conditions from the viewpoint of promoting the fixation of the dye to the polyhydroxyalkanete fibers during dyeing.

[0054] When dyeing, the dyeing time is defined as the time from when the maximum temperature of the process is reached until it is maintained. Preferably, the upper limit is 180 minutes or less, more preferably 120 minutes or less, and even more preferably 80 minutes or less. By limiting the dyeing time to 80 minutes or less, changes in physical properties such as strength due to heat during dyeing can be suppressed.

[0055] The staining method is not particularly limited, but overflow staining machines, jet staining machines, beam staining machines, Zigger staining machines, Wins staining machines, paddle staining machines, washer staining machines, jet staining machines, Gaston staining machines, HTHP staining machines, etc., can be used.

[0056] There are no particular restrictions on the type or composition of dyes contained in the dye solution during dyeing; synthetic dyes, natural dyes, etc., can be used. Synthetic dyes are not particularly limited and include, for example, disperse dyes, direct dyes, vat dyes, and metal-containing dyes (also called metal complex dyes), but disperse dyes are preferred from the viewpoint of uniform and deep dyeing and improving color fastness. Furthermore, from the viewpoint of reducing the environmental impact of the dyed fabric of this embodiment, it is preferable to use biodegradable dyes, and more preferably dyes with a biodegradability of 50% or more. By dyeing with dyes that have a low environmental impact or biodegradable dyes, the environmental impact can be reduced even if the polyhydroxyalkate-containing fibers decompose in the environment and the dye is released into the environment.

[0057] Polyhydroxyalkanate fibers have a dense crystalline structure, resulting in poor diffusion and fixation of dyes into the amorphous regions. Therefore, it is preferable to include dyeing aids in the dyeing solution during dyeing. There are no particular restrictions on dyeing aids; they include dispersants, uniforming agents, etc., and one or more of them may be included. Dyeing aids include those that have an affinity for the dye and those that have an affinity for the fiber. Using the former reduces the effective dye concentration in the dye bath from the beginning of dyeing, making it uniform. Using the latter allows for uniform correction through color transfer if uneven dyeing occurs. By using these dyeing aids, the dye can be uniformly dispersed inside the fiber, resulting in a darker color. There are no particular restrictions on the type of dispersant and uniforming agent; anionic (naphthalene sulfonate formaldehyde condensate, lignin sulfonate, alkylnaphthalene sulfonate, etc.), cationic (didecyldimethylammonium salt, etc.), and nonionic dispersants (polyoxyethylene alkyl ether, polyoxyalkylene derivatives, etc.) can be used. However, nonionic or anionic dispersants are preferred from the viewpoint of improving dispersion retention and dye transferability. Furthermore, it is even more preferable to use a composite dispersant that has both dispersion and uniforming functions, such as the Nikka Sun Salt series from Nikka Chemical Co., Ltd. and methylnaphthalene sulfonate formaldehyde condensate.

[0058] After dyeing, a washing process involving water rinsing, reductive washing, or soaping may be included as needed to improve color fastness. This washing process reduces the likelihood of discoloration and staining, limiting the garment's use and allowing it to be applied to a variety of clothing types.

[0059] The temperature of the dye solution during water dyeing, reductive washing, or soaping is preferably 71°C or higher, more preferably 80°C or higher, and even more preferably 90°C or higher. If the temperature of the dye solution is 71°C or higher, dyes that have not penetrated into the molecular structure through physical adsorption or other means and are prone to falling off during use can be efficiently removed, thereby improving colorfastness.

[0060] Reductive washing is a method of washing dyed fabrics using a reducing agent under highly alkaline conditions. From the viewpoint of sufficiently reducing and decomposing unfixed dyes remaining on the surface of the fabric and improving color fastness, the pH of the washing solution is preferably 8 or higher, more preferably 9 or higher, and even more preferably 10 or higher. The upper limit is preferably 13 or lower. If it is higher than 13, the polyhydroxyalkanetes will hydrolyze under high alkalinity, reducing the strength of the fabric. The type of reducing agent in the washing solution is not particularly limited, but hydrosulfite, thiourea dioxide, and other reducing agents that have reducing properties under alkaline conditions can be used. The washing time is preferably 30 minutes or less, and more preferably 300 minutes or less, from the viewpoint of maintaining the color of the dye itself. The lower limit is preferably 1 minute or more. If the washing time is shorter than 1 minute, washing will not be sufficient and the color fastness will decrease.

[0061] Washing with soaping agents is a method of washing dyed fabrics without using reducing agents. The type of soaping agent is not particularly limited, but from the viewpoint of removing unfixed dyes remaining on the surface of the fabric, anionic surfactants (e.g., New Soaper K-3, K-7, K-9A, BS-200, AC, Red Soaper NC-5, NC-15, etc.), cationic surfactants (e.g., New Soaper N-3, etc.), nonionic surfactants (e.g., New Soaper BS-50, etc.), water-soluble polymers, chelating agents, alkaline agents, reducing agents, etc. can be used, and any or a mixture of several of these may be used, and the composition is not particularly limited. The washing time is preferably 30 minutes or less, and more preferably 300 minutes or less, from the viewpoint of maintaining the color of the dye itself. The lower limit is preferably 1 minute or more. If the washing time is shorter than 1 minute, washing will not be sufficient and the color fastness will decrease.

[0062] The present invention will be specifically described below with reference to examples and comparative examples. Various physical properties and performance evaluations were measured by the following methods. <Physical Property Evaluation> (1) Ratio of the second monomer unit to the total monomer units (copolymerization ratio) An aliphatic copolymer polyester was dissolved in deuterated chloroform (chloroform-d, 99.8%, manufactured by Fujifilm Wako Pure Chemical Industries) to a concentration of 1.5% by mass, and used as the measurement sample. A nuclear magnetic resonance spectrometer (Bruker BioSpin AVANCE II 400) was used, with an observation frequency of 400 MHz, 64 integration cycles, a chemical shift reference of 7.26 ppm chloroform, and deuterated chloroform as the locking solvent, and 1H-NMR measurement was performed. When 4-hydroxybutyrate is included as the second monomer unit, let A be the integral value of the triplet peak observed at a chemical shift of 4.1 ± 0.2 ppm, and let B be the integral value of the quartet peak observed at a chemical shift of 5.3 ± 0.2 ppm. The copolymerization ratio C (mol%) was calculated using the following formula: C = (A / 2) / (A / 2 + B) × 100 [mol%]. When 3-hydroxyvalilate is included as the second monomer unit, let D be the integral value of the triplet peak observed at a chemical shift of 0.88 ± 0.2 ppm, and let E be the integral value of the doublet peak observed at a chemical shift of 1.25 ± 0.2 ppm. The copolymerization ratio F (mol%) was calculated using the following formula: F = (D / 3) / (D / 3 + E / 3) × 100 [mol%]. When 3-hydroxyhexanoate is included as the second monomer unit, G is defined as the integral value of the triplet peak observed at a chemical shift of 0.90 ± 0.2 ppm, and H is defined as the integral value of the doublet peak observed at a chemical shift of 1.30 ± 0.2 ppm. The copolymerization ratio I (mol%) was calculated using the following formula: I = (G / 3) / (G / 3 + H / 3) × 100 [mol%].

[0063] (2) After the fabric samples were dyed, the K / S values ​​were measured using a spectrophotometer (Gretagmacbeth Color-Eye 7000A) under the conditions of a D56 light source and a field of view of 10 degrees. The L* value and K / S value in the CIE 1976 L*a*b* color space were determined, and the average value from 10 measurement points was calculated. The K / S value was calculated using the reflectance R at 630 nm, which is the representative wavelength absorbed by the blue dye, using the following formula: K / S = (1 - R) ２ It is calculated by / 2R. When using red and yellow dyes, the K / S values ​​should be obtained using the reflectance around 410 nm and 530 nm, respectively.

[0064] (3) Crystallinity was measured using a differential scanning calorimeter (Perkin Elmer, DSC8500) equipped with an intracooler. The measurement atmosphere was nitrogen (20 ml / min), and the sample was completely melted by raising the temperature from -50°C to 200°C at a rate of 20°C / min and holding for 1 minute. The melting point peak appearing in the measured DSC curve (thermogram) was integrated to calculate the melting energy. The melting energy was expressed as J (J / g), and the degree of crystallinity K (%) was calculated using the following formula. The sample was approximately 1 mg, an aluminum sample pan was used, and indium was used for temperature calibration. Three measurements were taken, and the average value was taken as the degree of crystallinity. K = J / (146 × (100 - copolymerization ratio of the sample) / 100) × 100 (%)

[0065] <Performance Evaluation> (1) After cutting a practical strength fabric sample to 25 mm x 100 mm, the sample was clamped in the grips of a Tensilon universal testing machine (A&D Co., Ltd., RTG-1250) equipped with a 1 kN load cell at a gripping distance of 50 mm, and a tensile test was performed at a tensile speed of 100 mm / min. The load at which the sample broke was measured at 10 points, and the strength (N), which is the average value of these measurements, was calculated.

[0066] (2) Color fastness to washing A color fastness test to washing was conducted according to the test method of JIS L 0844:2011 A-2, and the grades of discoloration and staining (cotton) were evaluated. Five samples were used, and the lowest grade among the grades of each sample was used as the grade.

[0067] (3) Color fastness to friction The color fastness to friction test was evaluated using a dry friction test with a Type II friction tester (JSPS type) as specified in JIS L0849:2013 "Test method for color fastness to friction". Five samples were used, and the lowest grade among the grades of each sample was used as the grade.

[0068] [Example 1] Using the microorganism Cupriavidus necator H16 strain (ATCC17699 strain) as the PHA-producing microorganism, poly(3-hydroxybutyrate-co-3-hydroxyvalate) (hereinafter abbreviated as PHBV) with a copolymerization ratio of 1.5% was prepared by appropriately adjusting the raw materials and culture conditions. These pellets were melt-extruded in a melt extruder (AIKI Riotec ALM-S1000) heated to 170°C with a residence time of 600 seconds. Spinning was performed using a nozzle with a hole diameter of 0.23 mm and 36 holes. The extruded through an air gap section in 3 seconds while being drafted at 27 times the air gap ratio. It was then cooled in a cooling process at 5°C, stretched to a draw ratio of 4 times during the cooling process, and further stretched to 1.9 times at room temperature. Before winding, a 10% aqueous solution of Schill Seilacher Silastol R641 was applied using an oiling nozzle. Finally, it was wound on a winding machine to produce a drawn yarn consisting of 10,000 m of continuous multifilament filaments. Subsequently, it was processed on a tubular knitting machine (Eiko Sangyo One-Bite Test Tube Knitting Machine). A fiber sample was fed into an NCR-ES (Non-Cylinder Knitting System), and a tubular knitted fabric was produced on a tubular knitting machine equipped with a 28-gauge (3.5-inch diameter, 300 needles) knitting vat. The scale for determining the gauge (0-5, in 0.5 increments) was adjusted to 1.5. The prepared knitted fabric was immersed in 2 L of a 0.2% Tween20 (registered trademark) (Biorad, Cas No. 9005-64-5) aqueous solution and stirred for 10 minutes to scouring. After scouring, the sample was lightly dewatered and then dried at 30°C for 1 hour using a forced-air dryer (Yamato Scientific Co., Ltd. DKM401 forced-air constant-temperature incubator). Subsequently, the dried sample was heat-treated at 120°C for 30 minutes using the same dryer. Next, the obtained knitted fabric was dyed using a mini color dyeing machine (Texam Giken Co., Ltd.) Using a UR MINI-COLOR, 5 g of the sample was added to a stainless steel pot with a diameter of 72 mm and a height of 110 mm. 200 mL of staining solution was added (100 mL of distilled water, 0.1 g of acetic acid from Fujifilm Wako Pharmaceutical Co., Ltd., 0.2 g of sodium acetate from Fujifilm Wako Pharmaceutical Co., Ltd., 0.2 g of Nikka Sun Salt RM-340E from Nikka Chemical Co., Ltd., and 0.15 g of Dyster Dianix Blue S-2R, and the total volume was made up to 200 mL with distilled water), and staining was carried out at 120°C for 30 minutes. After staining, the samples were dried using a forced-air dryer at 30°C for 1 hour.After preparing and drying the dyed samples, they were placed in a 1 L Erlenmeyer flask with a lid. 500 mL of reducing detergent (400 mL of distilled water, 1 g of sodium hydroxide from Fujifilm Wako Pharmaceutical Co., Ltd., and 1 g of Cyclanon MCL liq from Arkroma Co., Ltd., then diluted to 500 mL with distilled water) was added, and the samples were washed with the reducing agent at 80°C for 30 minutes. The treated samples were collected, washed three times with 1 L of distilled water, and dried flat overnight. The resulting knitted fabrics were then evaluated for various physical properties and performance as shown in Table 1 below.

[0069] [Example 2] Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (hereinafter abbreviated as P3HB4HB) with a copolymerization ratio of 1.5% was prepared by adjusting the raw materials and culture conditions. Knitted fabric was prepared and dyed using the same method as in Example 1, and the resulting knitted fabric was evaluated for various physical properties and performance as shown in Table 1 below.

[0070] [Example 3] Using Aeromonas caviae strain (ATCC15468) as the production strain, the raw materials and culture conditions were adjusted to prepare poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (hereinafter abbreviated as PHBH) with a copolymerization ratio of 1.5%. Knitted fabric was prepared and dyed in the same manner as in Example 1, and the final obtained knitted fabric was evaluated for various physical properties and performance as shown in Table 1 below.

[0071] [Example 4] P3HB was prepared by adjusting the raw materials and culture conditions. The knitted fabric was made and dyed using the same method as in Example 1, and the final obtained knitted fabric was evaluated for various physical properties and performance as shown in Table 1 below.

[0072] [Example 5] Knitted fabric was prepared and dyed in the same manner as in Example 1, except that the culture conditions were adjusted to set the copolymerization ratio to 5.3%. The resulting knitted fabric was then evaluated for various physical properties and performance as shown in Table 1 below.

[0073] [Example 6] Knitted fabric was prepared and dyed in the same manner as in Example 1, except that the culture conditions were adjusted and the copolymerization ratio was set to 6.0%. The final obtained knitted fabric was then evaluated for various physical properties and performance as shown in Table 1 below.

[0074] [Example 7] Knitted fabric was prepared and dyed in the same manner as in Example 1, except that the culture conditions were adjusted and the copolymerization ratio was set to 10.0%. The resulting knitted fabric was then evaluated for various physical properties and performance as shown in Table 1 below.

[0075] [Example 8] Using strain ATCC15468, PHBH with a copolymerization ratio of 5.3% was prepared by adjusting the raw materials and culture conditions. The knitted fabric was prepared and dyed in the same manner as in Example 1, and the final obtained knitted fabric was evaluated for various physical properties and performance as shown in Table 1 below.

[0076] [Example 9] A knitted fabric was prepared and dyed in the same manner as in Example 1, except that the dyeing temperature was set to 130°C. The resulting knitted fabric was then evaluated for various physical properties and performance as shown in Table 1 below.

[0077] [Example 10] A dyed sample was prepared in the same manner as in Example 1, except that the dyeing temperature was set to 100°C. After drying, it was added to a 1 L Erlenmeyer flask with a lid, and 500 mL of reducing detergent (400 mL of distilled water, 1 g of sodium hydroxide manufactured by Fujifilm Wako Pharmaceutical Co., Ltd., and 1 g of Cyclanon MCL liq manufactured by Arkroma Co., Ltd. were added, and the total volume was made up to 500 mL with distilled water) was added. Washing with the reducing agent was performed at 80°C for 30 minutes. The treated sample was collected, washed three times with 1 L of distilled water, and dried flat overnight. The knitted fabric obtained was then evaluated for various physical properties and performance as shown in Table 1 below.

[0078] [Example 11] A knitted fabric was prepared and dyed in the same manner as in Example 1, except that the dyeing temperature was 86°C. The resulting knitted fabric was then evaluated for various physical properties and performance as shown in Table 1 below.

[0079] [Example 12] Knitted fabric was prepared and dyed in the same manner as in Example 1, except that Nikkasun Salt RM-340E, a dyeing auxiliary manufactured by Nikka Chemical Co., Ltd., was not added to the dyeing solution. The resulting knitted fabric was then evaluated for various physical properties and performance as shown in Table 1 below.

[0080] [Example 13] Knitted fabric was prepared and dyed in the same manner as in Example 1, except that a reduction washing treatment was not performed after dyeing. The resulting knitted fabric was then evaluated for various physical properties and performance as shown in Table 1 below.

[0081] [Comparative Example 1] A knitted fabric was prepared in the same manner as in Example 1, except that the dyeing temperature was changed to 85°C. The final obtained knitted fabric was then evaluated for various physical properties and performance as shown in Table 1 below.

[0082] [Comparative Example 2] A knitted fabric was prepared in the same manner as in Example 2, except that the dyeing temperature was changed to 85°C. The final obtained knitted fabric was then evaluated for various physical properties and performance as shown in Table 1 below.

[0083] [Comparative Example 3] A knitted fabric was prepared in the same manner as in Example 3, except that the dyeing temperature was changed to 85°C. The final obtained knitted fabric was then evaluated for various physical properties and performance as shown in Table 1 below.

[0084] [Comparative Example 4] A knitted fabric was prepared in the same manner as in Example 4, except that the dyeing temperature was changed to 85°C. The final obtained knitted fabric was then evaluated for various physical properties and performance as shown in Table 1 below.

[0085] [Comparative Example 5] A knitted fabric was prepared in the same manner as in Example 1, except that the culture conditions were adjusted and the copolymerization ratio was set to 15.0%. The final obtained knitted fabric was then evaluated for various physical properties and performance as shown in Table 1 below.

[0086] [Comparative Example 6] Using strain ATCC15468, PHBH was prepared with adjusted culture conditions and a copolymerization ratio of 6.0%. The dyeing temperature was set to 60°C, and dyeing was performed without adding any dyeing aids to the dyeing solution. Furthermore, no reduction washing treatment was performed after dyeing. The knitted fabric was prepared in the same manner as in Example 3, and the final obtained knitted fabric was evaluated for various physical properties and performance as shown in Table 1 below.

[0087]

[0088] The dyed fabric of the present invention contains marine biodegradable PHA fibers, possesses sufficient strength for practical use as clothing and industrial materials, and also exhibits excellent colorfastness. Therefore, the fabric of the present invention is suitably usable as a textile product that does not contribute to microplastic pollution.

Claims

1. A dyed fabric containing polyhydroxyalkanete fibers with a crystallinity of 50% or more, which contain 3-hydroxybutyrate as a monomer unit, and having a K / S value of 2 or more.

2. The dyed fabric according to claim 1, wherein the polyhydroxyalkanate is a copolymer containing a second monomer unit, and the second monomer unit is any of 3-hydroxyvaliate, 4-hydroxybutyrate, or 3-hydroxyhexanoate.

3. The dyed fabric according to claim 2, wherein the copolymerization ratio of the second monomer unit is 5 mol% or less.

4. The dyed fabric according to claim 1 or 2, wherein the degree of crystallinity of the polyhydroxyalkanet is 55% or more and 80% or less.

5. The dyed fabric according to claim 1 or 2, wherein the X-ray diffraction intensity ratio Iβ / Iα of the β structure and α structure of the polyhydroxyalkanete is 0 or more and 0.6 or less.

6. The dyed fabric according to claim 1 or 2, wherein the softening point of the polyhydroxyalkanet is 140°C or higher.

7. The dyed fabric according to claim 1 or 2, wherein the polyhydroxyalkanete is a multifilament long fiber.

8. The dyed fabric according to claim 7, wherein the number of filaments of the multifilament long fiber is 6 or more and 300 or less.

9. A method for dyeing a fabric containing polyhydroxyalkanete fibers having a crystallinity of 50% or more and containing 3-hydroxybutyrate as monomer units, wherein the temperature of the dyeing solution during dyeing is 86°C or higher and 120°C or lower.

10. The dyeing method according to claim 9, further comprising a washing step at 71°C or higher after dyeing.

11. The staining method according to claim 9 or 10, wherein the temperature of the staining solution is 90°C or higher.

12. The dyeing method according to claim 9 or 10, wherein the dye contained in the dyeing solution is a disperse dye.

13. The dyeing method according to claim 10, wherein the washing step is a reductive washing with a washing solution with a pH of 8 or higher.

14. The dyeing method according to claim 9 or 10, characterized in that the dyeing solution contains at least one selected from the group consisting of a dispersant, a uniforming agent, and an auxiliary dyeing agent.

15. The dyeing method according to claim 9 or 10, further comprising a washing step with a soaping agent after dyeing.

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