Fabric containing polyhydroxyalkanoate fiber and method for producing same

Abstract

Provided is a fabric suitable for dyeing, which has practically sufficient strength as a clothing / industrial material while containing a marine biodegradable polyhydroxyalkanoate (PHA) fiber, and which is also excellent in dyeability and dimensional stability during dyeing. The present invention relates to a fabric composed of polyhydroxyalkanoate fibers containing 3-hydroxybutyrate as a monomer unit, in which the X-ray diffraction intensity ratio Iβ / Iα of the β structure and the α structure of the polyhydroxyalkanoate is between 0 and 0.6 (both inclusive), a method for dyeing the fabric, and a method for producing the fabric.

Description

Fabric containing polyhydroxyalkanete fibers, and method for producing the same

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

[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 difficult because these polysaccharides have lower single-fiber strength than synthetic fibers, and it is not possible to create fabrics with the specific functions 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 in dark colors. 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 P3HB in dark colors while maintaining its properties before dyeing.

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

[0008] International Publication No. 2024 / 058076

[0009] The technology described in Patent Document 1 has a low dyeing temperature of 85°C or less, making it difficult to dye to a deep color. Furthermore, Patent Document 1 does not describe improvements to the dyeability of the fabric itself or the dimensional stability during dyeing. In view of these problems with the prior art, the problem that the present invention aims to solve is to provide a fabric suitable for dyeing that contains marine biodegradable PHA fibers, has sufficient strength for practical use as clothing and industrial materials, and further has excellent dyeability and dimensional stability during dyeing.

[0010] 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.

[0011] In other words, the present invention is as follows: [1] A fabric comprising polyhydroxyalkanate fibers containing 3-hydroxybutyrate as monomer units, wherein the X-ray diffraction intensity ratio Iβ / Iα of the β structure to the α structure of the polyhydroxyalkanate is 0 or more and 0.6 or less. [2] The fabric according to [1], wherein the softening point of the polyhydroxyalkanate is 140°C or higher. [3] The fabric according to [1] or [2], wherein the Iβ / Iα of the polyhydroxyalkanate is 0.2 or less. [4] The fabric according to any one of [1] to [3], wherein the polyhydroxyalkanate is a copolymer containing a second monomer unit, and the second monomer unit is 3-hydroxyvaliate, 4-hydroxybutyrate, or 3-hydroxyhexanoate. [5] The fabric according to [4], wherein the copolymerization ratio of the second monomer unit is 5 mol% or less. [6] The fabric according to any one of [1] to [5], wherein the degree of crystallinity of the polyhydroxyalkanate is 40% or more. [7] The fabric according to any one of [1] to [6], wherein the degree of crystallinity of the polyhydroxyalkanate is 70% or less. [8] The fabric according to any one of [1] to [7], wherein the degree of crystal orientation of the α structure of the polyhydroxyalkanate is 80% or more. [9] The fabric according to any one of [1] to [8], wherein the decrease in Iβ / Iα after standing in an environment of 100°C for 30 minutes is 0.1 or less.

[10] The fabric according to any one of [1] to [9], wherein the shrinkage stress of the polyhydroxyalkanate fiber at 120°C is 5 cN or less.

[11] The fabric according to any one of [1] to

[10] , wherein the dry heat shrinkage rate of the polyhydroxyalkanate fiber at 120°C is 0.01% or more and 20% or less.

[12] The fabric according to any one of [1] to

[11] , wherein the polyhydroxyalkanate fiber is a multifilament filament.

[13] The fabric according to

[12] , wherein the number of filaments of the multifilament is 6 or more and 300 or less.

[14] The fabric according to any one of [1] to

[13] , wherein it is a woven or knitted fabric that is not napped.

[15] The fabric according to any one of [1] to

[14] , wherein the weight ratio of the polyhydroxyalkanate fiber to the fabric is 85 wt% or more.

[16] An undyed fabric for dyeing, as described in any of [1] to

[15] above.

[17] A method for dyeing the fabric according to

[16] above, characterized in that the dyeing temperature is 86°C or higher.

[18] A method for manufacturing the fabric according to any of [1] to

[16] above, comprising the steps of making a fabric from polyhydroxyalkanete fibers containing 3-hydroxybutyrate as monomer units, and a heat treatment step of heat-treating the fabric at 71°C or higher.

[19] A method for manufacturing the fabric according to

[18] above, wherein a tension of 0.1 N or more is applied to the fabric in the heat treatment step.

[20] A method for manufacturing the fabric according to

[18] or

[19] above, wherein the elongation rate of the fabric in the heat treatment step is 101% to 130%.

[21] A method for manufacturing a fabric according to any one of

[18] to

[20] , wherein the heat treatment temperature in the heat treatment step is 100°C or more and 130°C or less.

[22] A method for manufacturing a fabric according to any one of

[18] to

[21] , wherein in the heat treatment step, the fabric is placed in a heat treatment environment for a time of 10 seconds or more and 1000 minutes or less.

[0012] The 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 dyeability and dimensional stability during dyeing.

[0013] Embodiments of the present invention will be described in detail below. One embodiment of the present invention is a fabric containing polyhydroxyalkanete fibers containing 3-hydroxybutyrate as monomer units, characterized in that 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.

[0014] The X-ray diffraction intensity ratio Iβ / Iα of the β structure and α structure of the polyhydroxyalkanete fiber constituting the fabric containing the polyhydroxyalkanete fiber of this embodiment is 0.6 or less, preferably 0.4 or less, more preferably 0.2 or less, even more preferably 0.1 or less, and particularly preferably 0. The lower limit of the X-ray diffraction intensity ratio Iβ / Iα of the β structure and α structure can be 0 or more. The β structure referred to here is a β-type crystal structure formed by elongated chains, which has low thermodynamic stability. When the unstable β structure disappears over time, it may be accompanied by fiber shrinkage and a decrease in mechanical properties. Therefore, if the X-ray diffraction intensity ratio Iβ / Iα of the β structure to the α structure is 0.6 or less, the less stable β structure is less likely to disappear over time. This results in less dimensional change and deterioration of mechanical properties during processing such as dyeing of the fabric, as well as suppression of deterioration of the fabric's texture due to shrinkage of the fiber structure. Furthermore, because changes in physical properties over time due to the disappearance of the β structure are less likely to occur when using the fabric, it also exhibits excellent storage stability. To achieve an Iβ / Iα ratio of 0.6 or less for the fabric, it is important to heat-treat the fabric at 71°C or higher, as described later.

[0015] 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.

[0016] The polyhydroxyalkanete 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. The softening point is the temperature at which the thermoplastic resin begins to deform during the process in which the amorphous portion of the thermoplastic resin changes from solid to liquid. By setting the X-ray diffraction intensity ratio Iβ / Iα and the softening point within a specific range, thermal stability is improved, and deterioration of the texture due to heat during processing of the fabric can be suppressed. As a result, a fabric with excellent texture can be obtained. In order to set the softening point to 130°C or higher, as described later, the polyhydroxyalkanete is a polyhydroxyalkanete containing 3-hydroxybutyrate as a monomer unit, and in the case of a copolymer containing 3-hydroxybutyrate and a second monomer unit, it is important to set the ratio of the second monomer unit to the total monomer units (hereinafter abbreviated as copolymerization ratio) to 5.3 mol% or less.

[0017] In this specification, the "softening point" can be measured by the following method. Using a Shimadzu CFT-500EX flow tester, the starting temperature was set to 100°C, the ending temperature to 200°C, the heating rate to 3°C / min, the test force to 30 kg, the preheating time to 240 seconds, the die bore diameter to 0.5 mm, and the die length to 1.0 mm. 2.0 g of sample was packed into the die, and the measurement was performed using the heating method. After the measurement, the softening point was calculated using the CFT-EX series software, determining the point at which the softening region was completed.

[0018] The polyhydroxyalkanate is preferably a polyhydroxyalkanate 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 3-hydroxyhexanoate, and even more preferably 3-hydroxyvariate. If the second component 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 can also 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.

[0019] 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 fabric, and furthermore, when fabricated, fiber breakage is less likely to occur during the process, and there is little decrease in strength during dyeing. The lower limit of the copolymerization ratio is preferably 1 mol% or more from the viewpoint of excellent moldability and high dispersibility of dyes within the crystalline structure.

[0020] 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.

[0021] The lower limit of the crystallinity of the polyhydroxyalkanete is preferably 40% or higher, more preferably 45% or higher, and even more preferably 50% or higher. If the crystallinity is 40% or higher, sufficient mechanical properties, especially strength, will be exhibited even after processing or dyeing of the fabric. 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 will disperse more easily within the crystalline structure during dyeing, making it easier to achieve a deeper color.

[0022] In this specification, "crystallinity" can be measured by the following method. Crystallinity is measured using a differential scanning calorimeter (PerkinElmer, 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 is 1 mg, and an aluminum sample pan is used. Indium is used for temperature calibration. K = J / (146 × (100 - copolymerization ratio of the sample) / 100) × 100 (%)

[0023] 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.

[0024] 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 [%].

[0025] The decrease in the X-ray diffraction intensity ratio Iβ / Iα of the β-structure after standing in a 100°C environment for 30 minutes is preferably 0.2 or less, more preferably 0.1 or less, and even more preferably 0.05 or less. If the decrease in Iβ / Iα after standing in a 100°C environment is 0.2 or less, there is less change in the crystalline structure due to the disappearance of the β-structure when the fabric is subjected to high-temperature processing such as dyeing or washing, resulting in less change in mechanical strength and dimensions.

[0026] In this specification, the "decrease in the X-ray diffraction intensity ratio Iβ / Iα of the β-structure and α-structure after standing in a 100°C environment for 30 minutes" can be measured by the following method. First, Iβ / Iα(N) of the sample before dry heat treatment is calculated based on the measurement method for the "X-ray diffraction intensity ratio Iβ / Iα of the β-structure and α-structure" described above. Next, after setting the forced-air dryer (Yamato Scientific, forced-air constant temperature incubator DKM401) to 100°C, the sample is placed inside the oven and left to stand for 30 minutes. After removing the sample, Iβ / Iα(O) is calculated based on the measurement method for the "X-ray diffraction intensity ratio Iβ / Iα of the β-structure and α-structure" described above. The "decrease in the X-ray diffraction intensity ratio Iβ / Iα of the β-structure and α-structure after standing in a 100°C environment for 30 minutes" (P) is calculated by the following formula: P = Iβ / Iα(O) after treatment - Iβ / Iα(N) before treatment

[0027] 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 when fabricated and dyed. Furthermore, the upper limit of the weight-average molecular weight is preferably 3,000,000 or less from the viewpoint of enabling practically stable molding processes.

[0028] 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 molding process is stable and the mechanical properties are 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.

[0029] 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). Samples of aliphatic copolymer polyester molded articles are similarly measured, and the weight-average molecular weight and number-average molecular weight are calculated from the calibration curve.

[0030] The shrinkage stress of polyhydroxyalkaneate fibers at 120°C is preferably 5 cN or less, more preferably 2 cN or less, and even more preferably 1 cN or less. Fiber shrinkage stress refers to the residual stress that accumulates inside the fiber due to tension or heating applied during spinning or post-processing. When the shrinkage stress at 120°C is 5.0 cN or less, dimensional changes in the fabric and deterioration of texture due to fiber shrinkage caused by residual stress during dyeing can be suppressed, making high-temperature dyeing possible and allowing for deep coloring. Similarly, changes in shape can be suppressed during washing after dyeing, and high-temperature washing is also possible, thus improving the colorfastness after dyeing.

[0031] In this specification, the "thermal shrinkage stress at 120°C" can be measured by the following method: A 100 mm length of fiber is cut from the fabric, and the fiber is placed in a thermal stress measuring device (KE-2S / PC, manufactured by Intec Co., Ltd.). The temperature is increased from 30°C to 120°C at a rate of 2.4°C / sec to obtain shrinkage stress data. The shrinkage stress at 120°C is then read and taken as the thermal shrinkage stress at 120°C.

[0032] The heat shrinkage rate of polyhydroxyalkaneate fibers at 120°C is preferably 35% or less, more preferably 30%, and even more preferably 20% or less. A shrinkage rate of 35% or less at 120°C suppresses dimensional changes in the fabric during dyeing, enabling high-temperature dyeing and achieving deep coloring. Similarly, changes in shape are suppressed during washing after dyeing, and high-temperature washing is also possible, thereby improving the colorfastness after dyeing. As a lower limit for the shrinkage rate, it is preferable to be 0.01% or more to prevent expansion after heating.

[0033] In this specification, the "heat shrinkage rate at 120°C" can be measured by the following method: A 100 mm fiber is drawn from the fabric, its length is measured, and then it is placed in a forced-air dryer set to 120°C and left to stand for 30 minutes. Afterward, the sample is removed, its length (A mm) is measured, and the "heat shrinkage rate at 120°C" (Q%) can be calculated using the following formula: Q = (100 (mm) - A (mm)) / 100 (mm) × 100 (%)

[0034] The structure of polyhydroxyalkanete fibers is not particularly limited, including monofilament yarn, multifilament yarn, and spun yarn. However, long fibers are preferred, and more preferably multifilament long fibers, because they offer high strength, reduced surface fuzz, and reduced environmental release during use when processed into fabric. When fabric is constructed from multifilament long fibers, the fineness of the single filaments decreases, and the total surface area of ​​the fibers increases, resulting in improved dyeability and a better texture and color when processed into fabric.

[0035] The upper limit of the number of filaments constituting a multifilament fiber is preferably 300 filaments or less, more preferably 250 filaments or less, even more preferably 200 filaments or less, and most preferably 150 filaments or less. If the number of fibers is 300 filaments or less, it is possible to improve dye dispersibility while suppressing fiber breakage during processing and use due to excessively low single-fiber fineness, thereby improving dyeability. The lower limit of the number of fibers can be appropriately adjusted depending on the total fineness of the fiber for the intended application, but it is preferably 6 filaments or more, more preferably 15 filaments or more, and even more preferably 30 filaments or more. By using 6 filaments or more, the texture of the fabric is better than with monofilament, and dye dispersibility can be improved, resulting in good dyeability.

[0036] The fineness of the single yarn constituting the polyhydroxyalkanete fiber is preferably 15 denier (D) or less, more preferably 10D or less, and even more preferably 5D or less. By making the fineness 15D or less, the texture of the fabric can be made softer, and furthermore, disperse dyes can penetrate more easily into the inside of the fiber, resulting in high dyeability.

[0037] In this specification, the "fineness of a single yarn" can be measured by the following method: Take 50 mg of fiber from the fabric, separate the constituent single yarns, measure the length of each, 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).

[0038] The type of fabric in this embodiment is not particularly limited, but it is preferably a woven or knitted fabric, more preferably a non-furred woven or knitted fabric. If it is a woven or knitted fabric, it has excellent mechanical strength and texture as a fabric. Also, if it is a non-furred 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 plain weave, twill weave, satin weave, 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 knitting machines, weft knitting machines, double circular knitting machines, tricot knitting machines, raschel knitting machines, 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 with practical strength cannot be created. The upper limit is preferably 60G or less from the viewpoint of industrial continuous production.

[0039] The basis weight of the 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, and even 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 from the viewpoint of being practical as clothing and industrial materials, more preferably 400 g / m ２ , and even 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 fabric is less likely to occur, resulting in a uniform and vivid color development.

[0040] The 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 functions of the fabric according to its use.

[0041] The weight ratio of the polyhydroxyalkanoate fiber constituting the fabric of the present embodiment is not particularly limited, but 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, the biodegradability of the entire fabric is ensured, and the environmental load when flowing out into the environment can be reduced. Further, even when a dyeing process specific to polyhydroxyalkanoate is used, 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.

[0042] The polyhydroxyalkanoate fiber constituting the 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.

[0043] 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. Further, 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.

[0044] 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 a method for 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 an extrusion port. 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.

[0045] The temperature for rapid cooling and fiberization after melt extrusion is preferably 30°C or lower, and more preferably 20°C or lower. While no lower limit is specifically set, it can usually be carried out at -200°C or higher for economic reasons. 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 also be stretched and wound in a cooling solvent.

[0046] 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 the cooling medium and passing the polyhydroxyalkate through it, using a fluid bath, using a cooling plate, using a cooling ring, and using a blower. Rapid cooling can be performed, for example, by extruding molten polyhydroxyalkate into a bath filled with a cooling medium at 30°C or below, and passing it through the solvent while being wound up by rollers in the bath.

[0047] 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, 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.

[0048] There are no particular restrictions on the method of fabricating the obtained polyhydroxyalkanete 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 an oil-applying touch roll or oiling guide in the spinning process, or it can be applied while rewinding the yarn after spinning.

[0049] 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.

[0050] Another embodiment of the present invention is a method for producing a fabric, comprising the steps of forming a fabric from polyhydroxyalkanete fibers containing 3-hydroxybutyrate as monomer units, and heat-treating the fabric at 71°C or higher. In this embodiment, it is preferable to heat-treat the fabric under appropriate conditions during spinning, after spinning, or after fabrication to eliminate the β structure. This makes it possible to improve dimensional stability even for polyhydroxyalkanetes, which have a low glass transition temperature Tg and are prone to morphological changes after processing. There are no particular restrictions on the heat treatment method, and heat treatment may be performed dry or wet 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 to rewind and process it using a machine such as a pin tenter while applying tension. 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, by treating it at a temperature of 71°C or higher, the β structure with low thermal stability is eliminated in advance, and by adjusting the X-ray diffraction intensity ratio Iβ / Iα of the β structure to α structure to 0 or more and 0.6 or less, changes in dimensions and physical properties over time during post-processing processes such as dyeing and during storage can be suppressed.

[0051] Heat treatment is preferably performed while the fabric is under tension. The tension is preferably 0.1 N or higher, more preferably 0.25 N or higher, and even more preferably 0.5 N or higher. By performing heat treatment under tension, the crystalline structure of the polymer during heat treatment is optimized under tension, which suppresses changes in the shape of the fabric during dyeing, enabling dyeing at high temperatures and achieving deep coloring. Similarly, changes in shape are suppressed during washing after dyeing, and high-temperature washing is also possible, thus improving the colorfastness after dyeing. The upper limit of the tension is preferably 20 N or lower, more preferably 10 N or lower, and even more preferably 5 N or lower, in order to prevent wrinkles from forming after heat treatment and to prevent the fabric structure from spreading.

[0052] The heat treatment is preferably carried out with an elongation rate of 100% or more, and more preferably 101% or more. By heat treating the fabric while it is slightly stretched, a uniform fabric structure can be achieved, wrinkles are less likely to occur after heat treatment, and changes in the shape of the fabric during dyeing and washing can be minimized. The upper limit of the elongation rate is preferably 140% or less, more preferably 130% or less, and even more preferably 120% or less, in order to minimize changes in the fabric structure and further suppress a decrease in weight.

[0053] The heat treatment time is preferably 10 seconds or more, more preferably 1 minute or more, and even more preferably 10 minutes or more. If it is less than 10 seconds, there will be insufficient thermal energy to eliminate the β-crystal structure, making it difficult to stabilize the crystalline structure of the fabric. There is no particular upper limit, but from the viewpoint of productivity, it is preferably 1000 minutes or less.

[0054] Another embodiment of the present invention is a method for dyeing the fabric, characterized in that the dyeing temperature is 86°C or higher. The fabric of this embodiment is suitable for dyeing. The dyeing method is not particularly limited, but a jet dyeing machine or a beam dyeing machine can be used. As dyes, direct dyes, reactive dyes, vat dyes, sulfur dyes, naphthol dyes, natural dyes, etc., can be used. The dyeing temperature is preferably 86°C or higher, and more preferably 90°C or higher. When the dyeing temperature is 86°C or higher, dimensional changes in the fabric are likely to occur, but with the fabric of the present invention, dimensional changes can be suppressed. Also, when the temperature is 86°C or higher, it is easy to dye to a dark color. The upper limit of the dyeing temperature is preferably 140°C or lower, and more preferably 130°C or lower. If dyeing at a temperature higher than 140°C, the fabric softens and a large change in shape occurs. Also, the texture deteriorates significantly due to welding of fibers together, and the mechanical strength also decreases.

[0055] 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) X-ray diffraction intensity ratio of β structure and α structure (Iβ / Iα) Using an X-ray structure evaluation device (Rigaku, SmartLab) and a multidimensional pixel array detector (Rigaku, HiPix-3000), the X-ray wavelength was set to 0.1 nm, the camera length to 27 mm, and the exposure time to 30 min. Five points of fiber, each 50 mm long, were cut from the fabric sample and 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 and β structures, each producing diffraction at specific positions, and the diffraction intensity is proportional to the amount of crystals. 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 of 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 crystal diffraction, the line connecting 2θ = 15° and 21°, where the influence of diffraction from the crystal is small, is considered to be 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 ratio Iβ / Iα, which is the average of the diffraction intensities at five points, was calculated.

[0056] (2) Softening point Using a Shimadzu CFT-500EX flow tester, the starting temperature was set to 100°C, the ending temperature to 200°C, the heating rate to 3°C / min, the test force to 30 kg, the preheating time to 240 seconds, the die hole diameter to 0.5 mm, and the die length to 1.0 mm. A total of 2.0 g of fabric sample was cut into 5 mm squares and packed into the die, and the measurement was performed using the heating method. After the measurement, the softening point was determined using the CFT-EX series software, and the same procedure was repeated five times to calculate the average value.

[0057] (3) Ratio of the second monomer unit to the total monomer units (copolymerization ratio) The 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 chloroform at 7.26 ppm, and deuterated chloroform as the locking solvent, and 1H-NMR measurements were performed. When 4-hydroxybutyrate was included as the second monomer unit, the integral value of the triplet peak observed at a chemical shift of 4.1 ± 0.2 ppm was taken as A, and the integral value of the quartet peak observed at a chemical shift of 5.3 ± 0.2 ppm was taken as B. The copolymerization ratio C (mol%) was 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%) 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 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%) was calculated using the following formula: I = (G / 3) / (G / 3 + H / 3) × 100 [mol%].

[0058] (4) 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 (%)

[0059] (5) Degree of crystal orientation of α-crystals An X-ray structure evaluation device (Rigaku, SmartLab) and a multidimensional pixel array detector (Rigaku, HiPix-3000) were used. The X-ray wavelength was set to 0.1 nm, the camera length to 27 mm, and the exposure time to 30 min. Five 50 mm sections of fiber were cut from the fabric sample and 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 was selected. All diffraction intensities with the same azimuthal angle were integrated, and this intensity was plotted against the azimuthal angle to create a one-dimensional azimuthal profile. At the locations where diffraction spots 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) was measured. When the FWHM is denoted as L, the degree of orientation M [%] was calculated using the following formula: M = (180 - L) / 180 × 100 [%]. Measurements were taken at five points, and the average value was used as the degree of orientation.

[0060] (6) Heat shrinkage stress at 120°C A 100 mm fiber was cut from the fabric and placed in a thermal stress measuring device (KE-2S / PC, manufactured by Intec Co., Ltd.). The temperature was raised from 30°C to 120°C at a rate of 2.4°C / sec to obtain shrinkage stress data. The shrinkage stress at 120°C was read, and the same procedure was repeated five times. The average value was calculated and used as the heat shrinkage stress at 120°C.

[0061] <Dyeing Method> The knitted fabric produced in the following examples was dyed using a mini-color dyeing machine (manufactured by Texam Giken Co., Ltd., 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, and 200 mL of the dyeing solution (100 mL of distilled water, 0.1 g of acetic acid manufactured by Fuji Film Wako Pure Chemical Corporation, 0.2 g of sodium acetate manufactured by Fuji Film Wako Pure Chemical Corporation, 0.2 g of Nikasansolt RM-340E manufactured by Nihon Kayaku Co., Ltd., and 0.15 g of Dianix Blue S-2R manufactured by Dyster were added and made up to 200 mL with distilled water) was added, and dyeing was carried out at 120 °C for 30 minutes.

[0062] <Performance Evaluation> (1) Practical Strength after Dyeing After cutting the dyed fabric sample into 25 mm × 100 mm, it was sandwiched between the gripping parts of a tensilon universal testing machine (A&D Company, Ltd., RTG-1250) with a load cell of 1 kN attached at a gripping distance of 50 mm, and a tensile test was carried out under the condition of a tensile speed of 100 mm / min. The load when the sample was cut was measured at 10 points, and the strength (N), which is the average value, was calculated.

[0063] (2) Dyeability After cutting the dyed fabric sample into 50 mm × 50 mm, colorimetry was carried out using a spectrophotometer (Color-Eye 7000A manufactured by Gretagmacbeth) under the conditions of a D56 light source and a viewing angle of 10 degrees, and the L* value and K / S value in the CIE1976L*a*b* color space were obtained, and the average value based on 10 measurement points was calculated. When the average value was 5 or more, it was evaluated as ○, when it was 2 or more and less than 5, it was evaluated as △, and when it was less than 2, it was evaluated as ×. The K / S value was calculated using the reflectance R at 630 nm, which is the representative wavelength absorbed by the blue dye, by the following formula: K / S = (1 - R) ２ / 2R.

[0064] (3) Dimensional change rate after dyeing After cutting the fabric samples before and after dyeing into 50 mm x 50 mm pieces, 10 magnified photographs of the fabric were taken at 20x magnification using a microscope (Keyence VHX7000). For each piece, the length of 10 loops in the wale direction and course direction of the knitted fabric was measured, and the average length in the wale direction and the average length in the course direction were calculated. The dimensional change rate was calculated for both the wale direction and the course direction using the following formula: L (%) = (Average length after dyeing (mm) - Average length before dyeing (mm)) / Average length before dyeing (mm) × 100

[0065] (4) Evaluation of fabric smoothness (texture) Ten subjects were asked to touch the samples and each was given a questionnaire about the smoothness. When eight or more people answered that they "felt the fabric was smooth" when they touched it, it was marked with ◎, when six or more people answered with ○, when three or more people answered with △, and when two or fewer people answered with ×.

[0066] [Example 1] Using the Cupriavidus necator H16 strain (ATCC17699 strain) as the production strain, 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. The extruded using a nozzle with a hole diameter of 0.23 mm and 36 holes, passed through an air gap for 3 seconds while being drafted at 27 times the air gap ratio, cooled in a cooling process at 5°C, stretched to a stretch 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, and finally wound on a winding machine to produce a fiber consisting of 10,000 m of continuous multifilament long fibers. Subsequently, a tubular knitting machine (Eiko Sangyo Ichikuchi Test Tubular Knitting Machine) equipped with a 28 gauge (boiler diameter: 3.5 inches, number of needles: 300) knitting bobbin was used. A fiber sample was fed into an NCR-ES (Non-Cutting Knitting System), and a tubular knitted fabric was produced by adjusting the gauge setting (0-5, in 0.5 increments) to 1.5 on a tubular knitting machine. The prepared knitted fabric was immersed in 2 L of a 0.2% Tween 20 (registered trademark) (Biorad, Cas No. 9005-64-5) aqueous solution and stirred for 10 minutes to perform scouring. After scouring, the sample was lightly dehydrated and then dried at 30°C for 1 hour using a forced-air dryer (Yamato Scientific Co., Ltd. forced-air constant-temperature incubator DKM401). Subsequently, the dried sample was heat-treated at 120°C for 30 minutes using the same dryer. Various physical properties and performance evaluations were performed as shown in Table 1 below.

[0067] [Example 2] PHBV with a copolymerization ratio of 10.0% was prepared by adjusting the raw materials and culture conditions. A knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0068] [Example 3] PHBV with a copolymerization ratio of 15.0% was prepared by adjusting the raw materials and culture conditions. A knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0069] [Example 4] PHBV with a copolymerization ratio of 16.0% was prepared by adjusting the raw materials and culture conditions. A knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0070] [Example 5] PHBV with a copolymerization ratio of 3.0% was prepared by adjusting the raw materials and culture conditions. A knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0071] [Example 6] PHBV with a copolymerization ratio of 5.0% was prepared by adjusting the raw materials and culture conditions. A knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0072] [Example 7] PHBV with a copolymerization ratio of 5.3% was prepared by adjusting the raw materials and culture conditions. A knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0073] [Example 8] PHBV with a copolymerization ratio of 5.5% was prepared by adjusting the raw materials and culture conditions. A knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0074] [Example 9] PHBV with a copolymerization ratio of 6.0% was prepared by adjusting the raw materials and culture conditions. A knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0075] [Example 10] P3HB was prepared by adjusting the raw materials and culture conditions. A knitted fabric was made in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0076] [Example 11] Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (hereinafter abbreviated as P3HB4HB) with a copolymerization ratio of 2.0% was prepared by adjusting the raw materials and culture conditions. A knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0077] [Example 12] Using Aeromonas caviae strain (ATCC15468 strain) 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 2.0%. Knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0078] [Example 13] Using strain ATCC15468, PHBH with a copolymerization ratio of 5.3% was prepared by adjusting the raw materials and culture conditions. A knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0079] [Example 14] Using strain ATCC15468, PHBH with a copolymerization ratio of 6.0% was prepared by adjusting the raw materials and culture conditions. A knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0080] [Example 15] Fibers made of multifilament continuous long fibers were prepared in the same manner as in Example 1. The warp and weft threads were made from the fibers prepared as described above, and weaving was carried out at 20 threads / inch for both the warp and weft. The warp threads were set on a loom (Toyoshima Business Systems automatic sample loom TNY101A-20), and the weft threads were passed through alternately up and down to form a plain weave structure. After that, heat treatment was performed in the same manner as in Example 1, and various physical properties and performance evaluations were carried out as shown in Table 1 below.

[0081] [Example 16] Spinning was carried out in the same manner as in Example 1, except that a nozzle with a pore diameter of 1.38 mm and one pore was used, to produce fibers consisting of monofilament continuous long fibers. After that, knitted fabric was prepared in the same manner as in Example 1, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0082] [Comparative Example 1] PHBV with a copolymerization ratio of 1.5% was prepared by adjusting the raw materials and culture conditions. The knitted fabric was prepared in the same manner as in Example 1, except that the knitted fabric was not heat-treated, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0083] [Comparative Example 2] P3HB4HB with a copolymerization ratio of 2.0% was prepared by adjusting the raw materials and culture conditions. The knitted fabric was prepared in the same manner as in Example 1, except that the knitted fabric was not heat-treated, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0084] [Comparative Example 3] Using strain ATCC15468, PHBH with a copolymerization ratio of 5.4% was prepared by adjusting the raw materials and culture conditions. The knitted fabric was prepared in the same manner as in Example 1, except that the knitted fabric was not heat-treated, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0085] [Comparative Example 4] PHBV with a copolymerization ratio of 10.0% was prepared by adjusting the raw materials and culture conditions. The knitted fabric was prepared in the same manner as in Example 1, except that the knitted fabric was not heat-treated, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0086] [Comparative Example 5] P3HB was prepared by adjusting the raw materials and culture conditions. The knitted fabric was made in the same manner as in Example 1, except that the knitted fabric was not heat-treated, and various physical properties and performance evaluations were performed as shown in Table 1 below.

[0087]

[0088] The 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 dyeability and dimensional stability during dyeing. Therefore, the fabric of the invention can be suitably used as a textile product that does not contribute to the microplastic problem.

Claims

1. A fabric comprising polyhydroxyalkate fibers containing 3-hydroxybutyrate as monomer units, wherein the X-ray diffraction intensity ratio Iβ / Iα of the β structure to the α structure of the polyhydroxyalkate is 0 or more and 0.6 or less.

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

3. The fabric according to claim 1 or 2, wherein the Iβ / Iα of the polyhydroxyalkanet is 0.2 or less.

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

5. The fabric according to claim 4, wherein the copolymerization ratio of the second monomer unit is 5 mol% or less.

6. The fabric according to claim 1 or 2, wherein the degree of crystallinity of the polyhydroxyalkanet is 40% or more.

7. The fabric according to claim 1 or 2, wherein the degree of crystallinity of the polyhydroxyalkane is 70% or less.

8. The fabric according to claim 1 or 2, wherein the degree of crystal orientation of the α structure of the polyhydroxyalkanete is 80% or more.

9. The fabric according to claim 1 or 2, wherein the decrease in Iβ / Iα after standing in an environment of 100°C for 30 minutes is 0.1 or less.

10. The fabric according to claim 1 or 2, wherein the shrinkage stress of the polyhydroxyalkanete fiber at 120°C is 5 cN or less.

11. The fabric according to claim 1 or 2, wherein the dry heat shrinkage rate of the polyhydroxyalkaneate fiber at 120°C is 0.01% or more and 20% or less.

12. The fabric according to claim 1 or 2, wherein the polyhydroxyalkaneate fiber is a multifilament long fiber.

13. The fabric according to claim 12, wherein the number of filaments of the multifilament is 6 or more and 300 or less.

14. The fabric according to claim 1 or 2, which is a woven or knitted fabric that is not napped.

15. The fabric according to claim 1 or 2, wherein the weight ratio of the polyhydroxyalkanete fibers to the fabric is 85 wt% or more.

16. The fabric according to claim 1 or 2, which is an undyed fabric for dyeing.

17. The method for dyeing fabric according to claim 16, characterized in that the dyeing temperature is 86°C or higher.

18. A method for producing a fabric according to claim 16, comprising the steps of forming a fabric from polyhydroxyalkanete fibers containing 3-hydroxybutyrate as monomer units, and a heat treatment step of heat-treating the fabric at 71°C or higher.

19. The method for manufacturing a fabric according to claim 18, wherein a tension of 0.1 N or more is applied to the fabric in the heat treatment step.

20. The method for manufacturing a fabric according to claim 18, wherein the elongation rate of the fabric in the heat treatment step is 101% to 130%.

21. The method for manufacturing a fabric according to claim 18, wherein the heat treatment temperature in the heat treatment step is 100°C or higher and 130°C or lower.

22. The method for manufacturing a fabric according to claim 18, wherein in the heat treatment step, the fabric is placed in a heat treatment environment for a period of 10 seconds or more and 1000 minutes or less.

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