Polyamide multifilament and fabric

Abstract

A polyamide multifilament has a bio-based carbon concentration of 50% or more, and has a content of coarse inorganic particles of 2.0 μm or more in a single yarn of 1,000 ppm or less.　In a biomass-derived polyamide multifilament, attention has been paid to aggregation of coarse inorganic particles derived from biomass and the content of coarse inorganic particles of 2.0 μm or more is reduced in a yarn, thereby providing a woven or knitted fabric excellent in high order process passage capability of a polyamide fiber obtained, tear strength and product quality.

Description

Polyamide multifilament and fabrics

[0001] The present invention relates to a biomass-derived polyamide multifilament.

[0002] Polyamide fiber, a synthetic fiber, is widely used in clothing applications such as innerwear and outdoor jackets due to its unique softness, high strength, abrasion resistance, and moisture absorption properties.

[0003] In recent years, growing awareness of the need to create a sustainable society has led to increased activity to move away from petroleum-based raw materials, and there is a demand for non-petroleum-based polyamide fibers as well. Known polyamide resins made from biomass as a non-petroleum raw material include polyamide 410, polyamide 510, polyamide 610, polyamide 612, polyamide 1010, and polyamide 11, which are made from corn or castor beans as starting materials.

[0004] Additionally, apparel brands that are leading the movement to move away from petroleum-based raw materials are in high demand for biomass materials in clothing applications, such as outdoor jackets, sportswear, innerwear, and other core products that use polyamide fiber.Furthermore, in recent years, there has been growing demand for soft-touch, lightweight, and pocketable materials, which requires fibers with finer single yarn diameters and higher strength.

[0005] As a spinning technology for biomass-derived polyamide, for example, Patent Document 1 provides a polyamide 610 multifilament that enables viscosity adjustment by optimizing the moisture content of the polymer during spinning, and has good fluff quality when drawn. Also, Patent Document 2 provides a polyamide multifilament that has a polyamide multifilament having an aliphatic hydrocarbon group of C7 or more, and that has good fluff quality by adding inorganic particles of a size that does not cause problems in fiber production, thereby creating fine irregularities on the fiber surface and reducing friction.

[0006] International Publication No. WO 2019 / 163971 International Publication No. WO 2023 / 136307

[0007] However, biomass-derived organic matter contains various metals necessary for the maintenance of life in living organisms, and these remain in the polymer as inorganic particles. Therefore, polyamide resins with a high bio-based content tend to aggregate as coarse inorganic particles. When these resins are used in fibers, the residual coarse inorganic particles in the fibers cause fuzzing and reduced strength in the raw yarn, making it more susceptible to yarn breakage during weaving and knitting, and can also cause poor quality, such as streaks, in the finished product.

[0008] The polyamide 610 multifilament described in Patent Document 1 is intended for industrial applications such as fishing nets, and is intended for fibers with a single filament fineness of 4.8 dtex or more, which is thicker than that used for clothing. Fine single filament products, which are primarily used for clothing, have a larger fiber surface area compared to the fineness range for industrial applications, and therefore are significantly affected by residual coarse inorganic particles, resulting in problems such as reduced strength, poor high-order passability due to fuzz, and poor tear strength and product quality. Furthermore, the polyamide multifilament described in Patent Document 2 is prone to filter clogging with coarse inorganic particles during melt spinning, which can cause a sudden increase in pack pressure and potentially worsen operability, and can also cause a decrease in strength due to the influence of residual coarse inorganic particles, potentially resulting in reduced tear strength of the woven fabric.

[0009] The present invention solves the above-mentioned problems and provides a polyamide fiber that is excellent in processability in advanced processing and can provide fabrics that are excellent in tear strength and product quality.

[0010] In order to solve the above problems, the present invention employs the following configurations. (1) A polyamide multifilament having a bio-based carbon concentration of 50% or more, wherein the content of coarse inorganic particles having a particle diameter of 2.0 μm or more in a single yarn is 1000 ppm or less. (2) The polyamide multifilament according to (1) above, wherein the single yarn fineness is less than 4.8 dtex. (3) The polyamide multifilament according to (1) or (2) above, wherein, in a drawn yarn having an elongation of 20 to 55%, the tenacity in the longitudinal direction of the fiber is 3.2 to 8.0 cN / dtex, the average continuous strength-elongation product is 6.0 or more, the minimum value is 5.0 or more, and the CV% is 4.0 or less. (4) The polyamide multifilament according to (1) or (2), wherein the highly oriented undrawn yarn has an elongation of 60 to 90%, and the tenacity in the longitudinal direction of the fiber is 2.1 to 6.0 cN / dtex, the average value of the continuous strength-elongation product is 5.0 or more, the minimum value is 4.0 or more, and the CV% is 3.5 or less. (5) A fabric partially comprising the polyamide multifilament according to any one of (1) to (4).

[0011] In biomass-derived polyamide multifilaments, by focusing on the aggregation of biomass-derived coarse inorganic particles and reducing the content of coarse inorganic particles having a particle diameter of 2.0 μm or more in the yarn, it is possible to provide woven and knitted fabrics having excellent high-order passability, tear strength, and product quality from the obtained polyamide multifilaments.

[0012] 1A and 1B show an embodiment of a polymer melting apparatus and an embodiment of a melt spinning apparatus.

[0013] The polyamide constituting the polyamide multifilament of the present invention may be produced by a polycondensation reaction using aminocarboxylic acid or cyclic amide as raw materials, or may be produced by a polycondensation reaction using dicarboxylic acid and diamine as raw materials.

[0014] Specifically, polyamides made from cyclic amides include polyamide 6 and polyamide 11, and polyamides made from dicarboxylic acids and diamines include polyamide 66, polyamide 410, polyamide 510, polyamide 610, polyamide 612, and polyamide 1010.

[0015] The smallest unit of raw materials that constitute the polyamide is collectively called a monomer. Examples of the monomer include petroleum-derived monomers, biomass-derived monomers, and mixtures of petroleum-derived monomers and biomass-derived monomers.

[0016] As mentioned above, the depletion of petroleum resources and global warming are becoming issues, and efforts to address environmental problems are being made on a global scale. As such, there is a demand for products that are derived from biomass and use environmentally friendly raw materials that do not rely on petroleum resources, and that are highly bio-based in order to contribute to the global environment.

[0017] Polyamides obtained from biomass-derived raw materials are obtained by polycondensation reactions using monomers such as sebacic acid and pentamethylenediamine, which are derived from castor beans or corn as starting materials.

[0018] The polyamide multifilament of the present invention is characterized in that the radioactive carbon ( １４ C) is 50% or more. A more preferred bio-based carbon concentration is 80% or more, and even more preferably 100%. By setting the bio-based carbon concentration within this range, it is expected that the amount of carbon dioxide emitted during polyamide production can be reduced. As a result, the generation of carbon dioxide during the production of polyamide multifilament can be reduced.

[0019] Here, the bio-based carbon concentration will be explained.

[0020] Generally, if the manufacturing method of a resin composition derived from plant-based raw materials and a resin composition derived from petroleum is the same, there is no difference in mechanical properties resulting from the polymer structure, such as molecular weight and crystallinity, or in thermal properties, such as melting point.

[0021] To distinguish the origin of raw materials, radioactive isotopes are used. １４ The bio-based carbon concentration can be calculated by measuring the carbon content of the plant. １４ Since it also incorporates C, it is only available in plant-based ingredients. １４On the other hand, petroleum feedstocks contain １４ It does not contain C, which is a radioactive isotope. １４ The concentration of bio-based carbon is measured by accelerator mass spectrometry to calculate the content ratio of plant-derived raw materials in the resin composition. The bio-based carbon concentration can be evaluated by radiocarbon analysis based on ASTM D6866 method (20-B).

[0022] Biomass-derived organic compounds contain various metal compounds necessary for maintaining the vital activities of living organisms, such as calcium, potassium, and magnesium (hereinafter referred to as biomass-derived residual inorganic particles). During the fiber production stage, the biomass-derived residual inorganic particles crystallize and aggregate to form coarse inorganic particles (hereinafter referred to as coarse inorganic particles) of 2.0 μm to 20.0 μm, which remain in the fiber. When the coarse inorganic particles remain in the fiber, breakage of the single yarn occurs starting from the coarse inorganic particles, resulting in single yarn breakage (fluffing). Furthermore, the breakage of the single yarn causes a decrease in strength.

[0023] In particular, in the case of polyamide fibers for clothing with small total fineness and single yarn fineness, the fiber diameter is small (thin), and the proportion of the particle diameter of coarse inorganic particles to the fiber diameter increases, so they are more affected.

[0024] For example, in a fiber with a single filament fineness of 0.20 dtex, if the particle diameter of the coarse inorganic particles is 2.0 μm, the coarse inorganic particles will account for 50% of the fiber diameter. If the particle diameter of the coarse inorganic particles is large, they will account for 50% or more of the fiber diameter of the single filament fineness exemplified above, and the coarse inorganic particles will be easily exposed from the fiber surface. Then, contact between the coarse inorganic particles exposed on the fiber surface and the yarn guide will cause fluffing, which will easily get caught on the reed or the like during the weaving process, increasing the risk of yarn breakage.

[0025] In this way, residual biomass-derived inorganic particles can deteriorate the high-order passability, reduce the strength of the raw yarn due to yarn breakage, thereby reducing the tear strength of the fabric, and induce defects such as streaks and unevenness due to tension fluctuations caused by fluff, thereby degrading the product quality.

[0026] In particular, polyamides with a bio-based carbon concentration of 50% by weight or more contain a large amount of residual inorganic particles derived from biomass, which tend to aggregate and are significantly affected by coarse inorganic particles, resulting in deterioration of high-order passability, tear strength, and product quality.

[0027] The polyamide multifilament of the present invention has a content of coarse inorganic particles having a particle diameter of 2.0 μm or more in a single yarn of 1000 ppm or less, preferably 500 ppm or less, and more preferably 300 ppm or less. By keeping the content of coarse inorganic particles at 1000 ppm or less, it is possible to suppress the generation of fluff and a decrease in strength, resulting in a polyamide fiber having excellent high-order passability, tear strength, and product quality.

[0028] The content of the coarse inorganic particles is determined by dissolving polyamide multifilaments in a solvent, filtering them through a 2 μm membrane filter, and calculating the content from the ash content of the inorganic particles remaining on the filter. The inorganic particles can be analyzed and quantified for metal compounds using, for example, ion chromatography or atomic absorption spectrometry. The particle diameter of the coarse inorganic particles is determined by replacing irregular particles with circumscribed rectangular parallelepipeds and taking the maximum major axis of the replaced rectangular parallelepiped as the particle diameter of the coarse inorganic particles.

[0029] Among clothing applications, innerwear and legwear in particular require soft fabrics because they come into direct contact with the skin. Furthermore, for outdoor jackets and down jackets, low breathability is required for fabrics to prevent wind and down loss, leading to advances in the use of finer single yarns and more filaments in polyamide multifilament.

[0030] The polyamide multifilament of the present invention preferably has a single yarn fineness of less than 4.8 dtex in order to achieve a soft feel and low breathability of the woven fabric, and more preferably has a single yarn fineness of 2.0 dtex or less.

[0031] The total fineness of the polyamide multifilament of the present invention can be appropriately set depending on the application, but the total fineness preferably used for clothing applications is 250 dtex or less, more preferably 10 to 200 dtex. In addition, it is preferable to design the number of filaments to be two or more, and the number of filaments to satisfy the above-mentioned range of single yarn fineness.

[0032] If residual biomass-derived inorganic particles are contained in only a small portion of the fiber in the longitudinal direction, the fiber will become weak with locally low strength and strength-strain product from that point onwards, reducing high-order passability and product quality.

[0033] The strength of the polyamide multifilament of the present invention is preferably 3.2 to 8.0 cN / dtex for drawn yarns with an elongation of 20 to 55%, and 2.1 to 6.0 cN / dtex for highly oriented undrawn yarns with an elongation of 60 to 90%. By setting the strength within these ranges, stable high-order processability can be achieved without yarn breakage even when subjected to high-order processing, and woven and knitted fabrics for clothing can be obtained that are excellent in fluff quality and dyeability, and also in tear strength.

[0034] The continuous strength-strain product (CV%) is a parameter that indicates the variation in the tensile strength-elongation curve in the longitudinal direction of the fiber; the lower the CV%, the smaller the variation in the tensile strength-elongation curve in the longitudinal direction of the fiber. There are no weak yarns with locally low strength-strain products, and when subjected to advanced processing, stable high-level passability is obtained without yarn breakage. Furthermore, because the fiber structure is stable, high-quality woven and knitted fabrics for clothing can be obtained without streaks or unevenness.

[0035] The CV% of the continuous strength-elongation product of the polyamide multifilament of the present invention is preferably 4.0 or less, more preferably 3.0 or less, for drawn yarns having an elongation of 20 to 55%, and is preferably 3.5 or less, more preferably 2.5 or less, for highly oriented undrawn yarns having an elongation of 60 to 90%.

[0036] The average value of the continuous strength-strain product is a parameter indicating the strength and elongation of the fiber, and is preferably 6.0 or more, and more preferably 7.5 or more, for drawn yarns with an elongation of 20 to 55%, and 5.0 or more, and more preferably 6.5 or more, for highly oriented undrawn yarns with an elongation of 60 to 90%. By setting the value within these ranges, stable high-order passability can be obtained without yarn breakage when the yarn is subjected to high-order processing.

[0037] Furthermore, the minimum value of the continuous strength-elongation product is a parameter indicating the lowest strength and elongation in the fiber longitudinal direction, and is preferably 5.0 or more, more preferably 6.0 or more, for drawn yarns with an elongation of 20 to 55%, and 4.0 or more, more preferably 5.0 or more, for highly oriented undrawn yarns with an elongation of 60 to 90%. The lower the minimum value of the continuous strength-elongation product, the more likely it is that points with locally low strength-elongation products will become weak yarn portions, making it more likely that yarn breakage or the like will occur from those points. By setting the minimum value of the continuous strength-elongation product within the above range, stable high-order processability can be achieved without yarn breakage even when subjected to high-order processing, and woven and knitted fabrics for clothing with excellent tear strength can be obtained.

[0038] The cross-sectional shape of the polyamide multifilament of the present invention is not particularly limited, and may be, for example, a round cross-section, a flat cross-section, a lenticular cross-section, a multilobal cross-section, a hollow cross-section, or any other known irregular cross-section.

[0039] The polyamide multifilament of the present invention may also contain various inorganic and organic additives, such as delustering agents, flame retardants, antioxidants, ultraviolet absorbers, infrared absorbers, nucleating agents, fluorescent brighteners, antistatic agents, moisture absorbers (e.g., polyvinylpyrrolidone), and antibacterial agents (e.g., silver zeolite, zinc oxide), as long as the additives have a particle size of less than 2.0 μm. If the additives described above are copolymerizable with polyamide, they may be copolymerized. The total content of these additives is preferably in the range of 0.001 to 10% by mass relative to the polyamide.

[0040] An example of producing the polyamide multifilament of the present invention will be given below.

[0041] Fig. 1 is a diagram schematically illustrating an example of a melt extruder for the polyamide multifilament of the present invention, Fig. 1(a) being a pressure melter type and Fig. 1(b) being an extruder type. In the present invention, a pressure melter type or an extruder type extruder equipped with a single screw is preferably used, but is not limited thereto.

[0042] FIG. 2 is a diagram schematically illustrating an example of a spinning machine for the polyamide multifilament of the present invention.

[0043] The polyamide multifilament of the present invention may be produced by any known melt spinning technique. The melt spinning method may be a two-step method (a method in which an undrawn yarn is once wound up and then drawn), a one-step high-speed spinning method (a method in which the spinning speed is set to 4000 m / min or higher and the drawing step is essentially omitted), or a high-speed spinning-drawing method (a method in which the spinning and drawing steps are carried out continuously).

[0044] An example of a one-step manufacturing method will be described with reference to FIG. 1(a) and FIG.

[0045] Polyamide chips are fed into a melt extruder, pushed through screw 1, and melted on hot plate 2. The resulting mixture is filtered through pre-filter 4 (first filtration zone) in the piping while being pressurized by booster pump 3, then filtered again through pre-filter 5 (second filtration zone), metered by gear pump 6, and introduced into spin pack 7. Within spin pack 7, the mixture is filtered again and discharged from the discharge holes of spinneret 11. The resulting yarn is cooled to room temperature and solidified by passing through a steam injection device located directly below the spinneret surface, where steam is injected toward the spinneret surface, and an area located downstream of the steam injection device, where cooling air is blown from cooling device 12. The yarn is then oiled by oil supply device 13 to bundle the yarn, entangled by fluid entanglement nozzle device 14, and passed through take-up roller 15 and stretching roller 16. The yarn is stretched by setting a peripheral speed ratio between the take-up roller and the stretching roller. Furthermore, the yarn is heat-set by heating with a drawing roller and then wound up by a winder 17 (winding device).

[0046] The moisture content of the polyamide chips is preferably 1000 to 1600 ppm. By setting the moisture content within this range, the melt viscosity becomes suitable for melt spinning, the polymer has good fluidity, the biomass-derived residual inorganic particles are uniformly dispersed, and the generation (aggregation) of coarse inorganic particles can be suppressed.

[0047] The melting temperature (temperature of the hot plate or heater) when melting the polyamide chips is preferably in the range of the melting point of the polymer plus (20°C to 80°C). When the melting temperature is (melting point + 20)°C or higher, the melt viscosity becomes suitable for melt spinning, the polymer has good fluidity, the remaining inorganic particles derived from biomass are uniformly dispersed, and the generation (aggregation) of coarse inorganic particles can be suppressed. When the melting temperature is (melting point + 80)°C or lower, thermal degradation of the polyamide can be suppressed. Suppressing thermal degradation allows the average value of the continuous strength-strain product to be controlled.

[0048] In the production of the polyamide multifilament of the present invention, in order to keep the content of coarse inorganic particles having a particle diameter of 2.0 μm or more in the fiber to 1000 ppm or less, filtration is carried out at least once each in the melt extruder and in the spin pack.

[0049] A common method for obtaining the same coarse inorganic particle removal rate by filtration in the spinning pack as when pre-filtration is used in combination is to make the mesh of the filter material finer. However, in this case, a large amount of coarse inorganic particles accumulate on the filter material and cause clogging, which causes an increase in pressure in the spinning pack, resulting in spinning problems such as polymer leakage, discharge abnormalities, and thread breakage. Therefore, when filtration is used only in the spinning pack, it is difficult to achieve both clogging and removal rate, and coarse inorganic particles are generated by aggregation of the remaining inorganic particles derived from the biomass, and the obtained multifilament contains more than 1000 ppm of coarse inorganic particles with a particle diameter of 2.0 μm or more.

[0050] It is extremely important that filtration within the melt extruder (hereinafter referred to as pre-filtration) is carried out at least once between the booster pump 3 and the gear pump 6, and that final filtration within the extruder is carried out immediately before flowing into the gear pump 6.

[0051] A filter is preferably used as the filtering material for pre-filtration, but is not limited thereto. It is preferable to use a filter with a mesh size of 10 to 20 μm for the pre-filtration filter. A mesh size of 10 μm or more enables stable filtration of polyamide without increasing pressure in the melt system due to filter clogging. A mesh size of 20 μm or less makes it possible to remove coarse inorganic particles from the polyamide fibers. Regarding the filter, any filter, such as a wire mesh type or a metal nonwoven fabric type, can be used as long as it can perform filtration normally.

[0052] In pre-filtration, in order to remove as many coarse inorganic particles as possible, the mesh of the filter can be made finer. However, simply making the mesh of the filter finer causes a large amount of coarse inorganic particles to accumulate on the filter in the melting system, causing clogging. As a result, pressure rises in the extruder piping, making stable melting difficult. Therefore, it is preferable to replace the filter periodically before clogging occurs, or to perform pre-filtration twice or more times.

[0053] If pre-filtration is performed in two or more stages, two or more pre-filters should be installed in the piping immediately before the gear pump (Fig. 1, 4 and 5). The mesh of the filters should be finer for pre-filter 5 downstream than for pre-filter 4 upstream.

[0054] In particular, in the case of polyamide fibers for clothing having a fine single yarn size, it is preferable that the upstream pre-filter 4 uses a mesh of 15 to 20 μm and the downstream pre-filter 5 uses a mesh of 10 to 15 μm.

[0055] In pre-filtration, the aggregation of residual inorganic particles derived from biomass (the generation of coarse inorganic particles) can be suppressed by shortening the polymer residence time. The residence time here refers to the melting and filtration time from the pre-filtration filter 5 to just above the spin pack, and can be calculated from the discharge rate and piping length. In order to shorten the melting and filtration time, it is preferable to position the downstream pre-filtration filter 5 as close as possible to the gear pump 6, as this shortens the piping length between the downstream pre-filtration filter 5 and just above the spin pack.

[0056] The melting and filtration time is preferably 10 minutes or less. If it is 10 minutes or less, re-agglomeration of remaining inorganic particles derived from biomass in the pipe can be suppressed, and the amount of coarse inorganic particles in the fiber can be reduced. In particular, in the case of polyamide fibers for clothing with small total fineness and single yarn fineness, the output rate is small and the melting and filtration time is likely to be long. Therefore, in order to increase the output rate, it is preferable to increase the number of yarn threads per spinneret and spin at a high winding speed of 4000 m / min or more.

[0057] After pre-filtration, filtration is performed in the spin pack. The polymer flowing into the spin pack contains residual inorganic particles derived from the biomass and inorganic particles smaller than 2.0 μm that have aggregated in the piping, so these particles are further dispersed and re-agglomeration is suppressed. This filtration in the spin pack can be performed using a known filtration technique.

[0058] For example, a method for improving dispersibility is to stack several types of filter media such as a filter or sand directly above the spinneret. In order to improve dispersibility, a filter placed directly above the spinneret, and although the mesh depends on the discharge rate, a nonwoven fabric filter made by SAS and a filter with a mesh of 2 to 5 μm are preferred. By setting the filter mesh within this range, coarse inorganic particles can be finely dispersed without increasing pressure due to filter clogging, and the amount of coarse inorganic particles with a particle diameter of 2 μm or more can be controlled to 1000 ppm or less.

[0059] On the other hand, there is also a method of adding chips that have been previously filtered, but there are still a number of residual inorganic particles derived from the biomass in the polymer, and these particles will re-aggregate in the melt system during fiber production to form coarse inorganic particles. Therefore, it is preferable to carry out pre-filtration and filtration in the spinning pack consecutively during fiber production.

[0060] Therefore, from the viewpoint of suppressing clogging (suppressing an increase in the internal pressure of the spin pack) and the removal rate of coarse inorganic particles, it is preferable to perform filtration in the melt extruder and filtration in the spin pack at least once each, or to perform filtration in the melt extruder and filtration in the spin pack continuously. By using such a method, in a polyamide multifilament having a bio-based carbon concentration of 50% or more, the content of coarse inorganic particles of 2.0 μm or more in the fiber can be controlled to 1000 ppm or less. Furthermore, by controlling the content of coarse inorganic particles of 2.0 μm or more in the fiber to 1000 ppm or less, the variation in the continuous strength-strain product can also be suppressed, and the average value, CV%, and minimum value can be within preferred ranges.

[0061] When the polyamide multifilament of the present invention is made into a highly oriented undrawn yarn, it can be processed into a yarn by a commonly used method, which can be appropriately selected from friction false twisting, pin false twisting, composite false twisting, Taslan processing, and the like.

[0062] The fabric made of the polyamide multifilament of the present invention is produced by a known production method. It may be in any form, such as a woven fabric or a knitted fabric such as a circular knit or warp knit. Furthermore, when forming a fabric, the polyamide multifilament may be used alone, or the polyamide may be used at least in part, i.e., when the fabric is composed of multiple types of fibers, as one of the multiple fibers constituting the fabric. The fabric can be used for clothing applications such as sports and casual wear such as shirts and blousons, pants, coats, women's and men's clothing, innerwear such as camisoles and shorts, and leg knits such as stockings and socks.

[0063] The present invention will be described in more detail below with reference to examples.

[0064] A. Total fineness and single yarn fineness The fibers were measured for a specified yarn length of 100 m using a measuring machine manufactured by Nakayama Electric Industry Co., Ltd., based on JIS L1013 (2010) 8.3.1 Correct fineness a) Method A, applying an initial load of the indicated fineness x 0.45 mN / dtex. This was taken as the total fineness. The single yarn fineness was calculated by dividing the fineness by the number of filaments.

[0065] B. Continuous strength and elongation product, CV% A fiber was measured 50 times (total length 25 m) using a Tensilon manufactured by Orientec Co., Ltd. in a temperature-controlled room at an air temperature of 20°C and a humidity of 65% under constant-speed elongation conditions in accordance with JIS L1013 (2010), with a grip distance of 50 cm and a pulling speed of 50 cm / min.

[0066] The tenacity was determined from the point showing the maximum tenacity in the tensile strength-elongation curve, and the elongation was determined from the elongation showing the maximum tenacity. The tenacity was calculated by dividing the maximum tenacity by the total fineness.

[0067] The continuous strength-strain product was calculated by the following formula, and the minimum and average values ​​of the individual values ​​measured 50 times, as well as CV% were calculated.

[0068] Continuous strength-strain product = strength [cN / dtex] x (1 + elongation [%] / 100) CV% = (standard deviation of continuous strength-strain product) / (average value of continuous strength-strain product) x 100.

[0069] C. Inorganic Particle Content 10 g of fiber was dissolved in 200 g of a solvent (PhOH / EtOH = 86.5 / 13.5), and the solution was filtered through a 2 μm membrane filter. The filter and the residue on the filter were heated in an electric furnace at 800 °C for 2 hours, and the resulting ash was dissolved in 5 mL of concentrated sulfuric acid. The solution was then filled up to a 10 mL measuring flask with concentrated sulfuric acid. The ash content (A μg) was determined using an ICP emission spectrometer (ICPE-9800) in accordance with JIS K0133 (2007), and the content of coarse inorganic particles of 2 μm or more in the yarn was calculated.

[0070] Coarse inorganic particle content (weight ppm) = Aμg / 10g.

[0071] D. Coarse Inorganic Particle Diameter In a similar manner, a solution of 10 g of fiber dissolved in 200 g of solvent was filtered through a 2 μm membrane filter, and the filter was vacuum-dried and placed in a petri dish. The filter was then dried in a dryer at 60°C for 12 hours and observed using a Keyence Corporation digital microscope "VHX-6000" and lens "VHX-D510" in accordance with JIS K0132 (1997). The particle diameter of the coarse inorganic particles was determined by replacing the irregular particles with circumscribed rectangular parallelepipeds, and the maximum major axis of the replaced rectangular parallelepiped was defined as the particle diameter of the coarse inorganic particles. The particle diameter (μm) of the total amount of coarse inorganic particles within any 100 × 100 μm area on the filter was measured, and the average value was defined as the particle diameter (D).

[0072] E. Biobased Carbon Concentration The resulting fiber samples were analyzed for biobased carbon concentration by radiocarbon analysis according to ASTM D6866.

[0073] F. Evaluation of Woven Fabric Products (a) Feeling The softness of the woven fabrics obtained in the Examples and Comparative Examples was evaluated by five examiners with extensive experience in evaluating feeling. Evaluation was made relative to the Reference Example.

[0074] The following evaluation points were taken by each examiner, and the average of the five examiners (rounded to the nearest whole number) was given an A for 3 points, a B for 2 points, and a C for 1 point.

[0075] 3 points: excellent 2 points: average 1 point: poor A and B were considered to be acceptable in terms of texture.

[0076] (b) Tear Strength The tear strength of the woven fabrics obtained in the Examples and Comparative Examples was measured at 10 random locations according to JIS L-1096 (2010) (8.17 A method), and the average and minimum values ​​were measured. Evaluation was made on a four-point scale based on the following criteria.

[0077] A: Average value 4.0N or more, minimum value 3.5 or more B: Average value 3.5N or more and less than 4.0N, minimum value 3.0 or more and less than 3.5 C: Average value 2.0N or more and less than 3.5N, minimum value 1.5 or more and less than 3.0 D: Average value less than 2.0N, minimum value less than 1.5 A and B were rated as pass.

[0078] (c) Product quality: The occurrence of unevenness and streaks was visually inspected per 50 m of fabric and evaluated according to the following criteria.

[0079] A: No streaks or unevenness, excellent quality B: Slight streaks or unevenness, but no problem for use as a product C: Streaks or unevenness, not suitable for use as a product A and B were deemed acceptable.

[0080] (d) High-order passability Ten plain weave fabrics (1000 m / weave) were woven on a water jet loom at a loom rotation speed of 750 rpm with a weft length of 1620 mm. The number of times the loom was stopped due to yarn breakage was evaluated according to the following criteria.

[0081] A: Less than 2 times B: 2 times or more but less than 4 times C: 4 times or more but less than 6 times D: 6 times or more A and B were considered to be acceptable.

[0082] Example 1 (Production of drawn polyamide yarn) Polyamide 510 chips (relative viscosity in sulfuric acid: 2.8, melting point: 218°C) having a bio-based carbon concentration of 100% as polyamide were fed into a pressure melter-type extruder equipped with a single screw as shown in Figure 1(a), melted at a melting temperature of 280°C, and filtered through pre-filtration filter 4 (first filtration zone, metal nonwoven fabric filter mesh: 20 µm) and pre-filtration filter 5 (second filtration zone, metal nonwoven fabric filter mesh: 10 µm) in the piping while applying pressure with booster pump 3, metered by gear pump 6, and then flowed into spin pack 7. The melting and filtration time from pre-filtration filter 5 to just above the spin pack was 5 minutes.

[0083] In addition, a spinneret (discharge hole diameter 0.20 mm, hole length 0.70 mm, round hole, 80 holes), a metal nonwoven fabric filter (made of SUS, mesh: 2 μm) was placed directly above the spinneret, and a melt spinning pack consisting of a pressure plate and a sand filter material was used. Filtration was again carried out in the spinning pack 7, and after being discharged from the discharge hole of the spinneret 11, the spun yarn was cooled to room temperature by a steam injection device in which steam was injected toward the spinneret surface provided directly below, and a cooling device 12 provided downstream of the steam injection device, and cooling air was blown from the cooling device 12, and then oil was added by an oil supply device 13, and then entanglement was imparted by a fluid entanglement nozzle device 14, and the peripheral speed (take-off speed) of the take-off roller 15 was set to 3460 m / min (set value) and taken-off.

[0084] The yarn taken up by the take-up roller 15 was then taken up by the drawing roller 16, whose surface temperature was 170°C, and drawn between the rollers (between rollers (15) and (16)) to a draw ratio of 1.40. The drawn yarn was then wound on a winder 17, set at a winding speed of 4,500 m / min (preset value), to obtain a 22 dtex-20 filament polyamide 510 drawn yarn (four fiber yarn packages). During spinning, there was no sudden increase in pack pressure or yarn breakage, and production was extremely stable. The evaluation results of the obtained polyamide 510 drawn yarn are shown in Table 1. (Fabric Production) One thousand strands of the obtained polyamide 510 drawn yarn were warped and wound around a beam, and the yarn wound around the beam was sized and dried to prepare the warp. The yarn was then passed through the reed of a water jet loom, and the obtained multifilament yarn was woven into a plain weave fabric by beating it into a weft. The woven fabric was scoured, heat-set at 170°C (intermediate set), dyed, and calendered at 170°C to obtain a fabric for an outdoor jacket. The evaluation results of the obtained fabric are shown in Table 1. The high-order passability of the fabric production was extremely good. The texture was also excellent, and the tear strength and product quality were also excellent.

[0085] Examples 2 and 3 A 22 dtex-20 filament drawn polyamide 510 yarn was obtained in the same manner as in Example 1, except that the chip moisture content was changed as shown in Table 1. The evaluation results are shown in Table 1.

[0086] Examples 4 and 5 A 22 dtex-20 filament polyamide 510 drawn yarn was obtained in the same manner as in Example 1, except that the melting temperature was changed as shown in Table 1. The evaluation results are shown in Table 1.

[0087] Comparative Example 1 A 22 dtex-20 filament drawn polyamide 510 yarn was obtained in the same manner as in Example 1, except that only filtration was performed in the spin pack (no pre-filtration step) and the mesh of the metal nonwoven fabric filter in the spin pack was changed as shown in Table 1. The evaluation results are shown in Table 1.

[0088] Example 6 A 22 dtex-20 filament drawn polyamide 510 yarn was obtained in the same manner as in Example 1, except that the pre-filtration step was performed only in the second filtration zone, filtration was performed from the booster pump 3 through a pre-filtration filter 5 (metal nonwoven fabric filter mesh: 10 μm), and the mesh of the metal nonwoven fabric filter in the spinning pack was changed as shown in Table 1. The evaluation results are shown in Table 1.

[0089] Example 7, Comparative Example 2 A 22 dtex-20 filament drawn polyamide 510 yarn was obtained in the same manner as in Example 1, except that the mesh of the metal nonwoven fabric filter in the spin pack was changed as shown in Table 1. The evaluation results are shown in Table 1.

[0090]

[0091] Comparative Example 3, Example 8 A spinneret having a discharge hole diameter of 0.20 mm, a hole length of 0.70 mm, round holes, and the number of holes shown in Table 2 was used, and the draw ratio was changed to 1.60, and the melting and filtration time from passing through the pre-filtration filter to just above the spin pack was set to 2 minutes, but the same method as in Example 1 was used to obtain polyamide 510 drawn yarns (two fiber yarn packages) of 78 dtex-20 and 122 dtex-20 filaments. The evaluation results are shown in Table 2.

[0092] Example 9 A 22 dtex-100 filament polyamide 510 drawn yarn (three fiber yarn packages) was obtained in the same manner as in Example 1, except that a spinneret with a discharge hole diameter of 0.20 mm, a hole length of 0.70 mm, round holes, and 300 holes was used, the draw ratio was changed to 1.10, the take-up speed was changed to 4,300 m / min, and the melting and filtration time from passing through the pre-filtration filter to just above the spin pack was set to 7 minutes. The evaluation results are shown in Table 2.

[0093] Comparative Example 4, Example 10 A 22 dtex-20 filament drawn polyamide 510 yarn was obtained in the same manner as in Example 1, except that the mesh of the metal nonwoven fabric filter in the spin pack, the number of spinneret holes, the discharge rate, and the number of yarn threads were changed as shown in Table 2, and the melting and filtration time from passing through the pre-filtration filter to just above the spin pack was adjusted. The evaluation results are shown in Table 2.

[0094] Example 11 A 22 dtex-20 filament drawn polyamide 510 yarn was obtained in the same manner as in Example 1, except that the concentration of titanium oxide particles with a particle diameter of 0.3 μm in the yarn was changed as shown in Table 2. The particle diameter of titanium oxide was measured by observing the polyamide resin containing titanium oxide particles using a Keyence Corporation digital microscope "VHX-6000" and lens "VHX-D510" in accordance with JIS K0132 (1997). For each particle observed, the maximum length (Dmax) and minimum length (Dmin) were measured, and the average value (Dave) was calculated. The same procedure was then repeated to determine the average value (Dave) for 100 particles, and this average value per 100 particles was defined as the particle diameter (D). The evaluation results are shown in Table 2.

[0095]

[0096] Example 12 (Production of highly oriented undrawn polyamide yarn) As in Example 1, a polymer was allowed to flow from a melt extruder into a spinning pack, filtered again in the spinning pack 7, and discharged from the discharge holes of the spinneret 11. The spun yarn was then cooled to room temperature and solidified by a steam injection device provided directly below the spinneret surface from which steam was injected, and by a cooling device 12 provided downstream of the steam injection device from which cooling air was blown. The yarn was then oiled by an oiling device 13, entangled by a fluid entanglement nozzle device 14, and taken up at a peripheral speed (take-up speed) of 4,028 m / min (set value) of a take-up roller 15. Subsequently, the yarn taken up by the take-up roller 15 was taken up between drawing rollers 16 (between rollers 15 and 16) at a draw ratio of 1.0, which had a surface temperature of 30°C, and wound on a winder 17 set at a take-up speed of 4000 m / min (set value), to obtain a highly oriented undrawn polyamide 510 yarn (four fiber yarn packages) of 26 dtex-20 filaments. The evaluation results of the obtained highly oriented undrawn polyamide 510 yarn are shown in Table 3. (Yarn processing) The obtained highly oriented undrawn yarn was subjected to draw-friction false-twist processing using a three-axis friction disk type draw-friction false-twist device. The yarn was fed from a feed roller at a peripheral speed of 550 m / min to a contact-type false-twist heater heated to 170°C, drawn 1.5 times, and subjected to simultaneous drawing and false-twisting at a disk rotation speed of 7500 rpm, a disk diameter of φ51, a D / Y ratio of 2.18, and a false-twist coefficient of 30,000, to obtain a 22 dtex-20 filament polyamide 510 false-twist textured yarn. The resulting false-twist textured yarn was woven in the same manner as described in Example 1. D: feed roller speed (m / min), Y: disk rotation speed (m / min). The resulting polyamide 510 false-twist textured yarn was woven in the same manner as in Example 1. The evaluation results are shown in Table 3.

[0097] Example 13 A highly oriented undrawn polyamide 510 yarn of 26 dtex-20 filaments was obtained and yarn processed in the same manner as in Example 12, except that the pre-filtration step was performed only in the second filtration zone, filtration was performed from the booster pump 3 through a pre-filtration filter 5 (short metal fibers, filtration filter mesh: 10 μm), and the mesh of the metal nonwoven fabric filter in the spinning pack was changed as shown in Table 3. The evaluation results are shown in Table 3.

[0098] Example 14 A highly oriented undrawn polyamide 510 yarn of 26 dtex-20 filaments was obtained and yarn processed in the same manner as in Example 12, except that the mesh of the metal nonwoven fabric filter in the spin pack, the number of spinneret holes, the discharge rate, and the number of yarn threads were changed as shown in Table 3, and the melting and filtration time from passing through the pre-filtration filter to just above the spin pack was adjusted. The evaluation results are shown in Table 3.

[0099] [Comparative Example 5] A highly oriented undrawn polyamide 510 yarn of 26 dtex-20 filaments was obtained and yarn processed in the same manner as in Example 12, except that only filtration in the spin pack was performed (no pre-filtration step) and the mesh of the metal nonwoven fabric filter in the spin pack was changed as shown in Table 3. The evaluation results are shown in Table 3.

[0100]

[0101] Example 15 A 22 dtex-20 filament polyamide 610 drawn yarn was obtained in the same manner as in Example 1, except that polyamide 610 (relative viscosity in sulfuric acid: 2.7, melting point: 220°C) was used and the draw ratio was changed to 1.30 times, and a woven fabric was produced in the same manner as in Example 1. The evaluation results are shown in Table 4.

[0102] Example 16 A 22 dtex-20 filament polyamide 410 drawn yarn was obtained in the same manner as in Example 1, except that polyamide 410 (relative viscosity in sulfuric acid: 2.8, melting point: 250°C) was used and the draw ratio was changed to 1.40 times, and a woven fabric was produced in the same manner as in Example 1. The evaluation results are shown in Table 4.

[0103] Example 17 A 22 dtex-20 filament polyamide 11 drawn yarn was obtained using polyamide 11 (relative viscosity in sulfuric acid: 2.0, melting point: 187°C) in the same manner as in Example 1, except that the melting temperature was changed to 240°C and the draw ratio was changed to 1.50 times, and a woven fabric was produced in the same manner as in Example 1. The evaluation results are shown in Table 4.

[0104] [Reference Example] A polyamide 6 multifilament having 22 dtex-20 filaments was obtained in the same manner as in Example 1, except that a C6 aliphatic hydrocarbon group polyamide 6 (relative viscosity in sulfuric acid: 2.7, melting point: 220°C) was used as the polyamide type and the draw ratio was changed to 1.7 times.

[0105] There were no residual inorganic particles derived from the biomass, and the amount of coarse inorganic particles was 0%. The evaluation results are shown in Table 4.

[0106]

[0107] 1: Screw 2: Hot plate 3: Booster pump 4: Pre-filtration filter (first filtration zone) 5: Pre-filtration filter (second filtration zone) 6: Gear pump 7: Spinning pack 8: Screw 9: Heater 10: Barrel 11: Spinneret 12: Cooling device 13: Oil supply device 14: Fluid entangling nozzle device 15: Take-up roller 16: Stretching roller 17: Winder (winding device)

Claims

1. A polyamide multifilament having a bio-based carbon concentration of 50% or more, in which the content of coarse inorganic particles having a particle diameter of 2.0 μm or more in a single yarn is 1,000 ppm or less.

2. The polyamide multifilament according to claim 1, having a single yarn fineness of less than 4.8 dtex.

3. The polyamide multifilament according to claim 1 or 2, in which, in a drawn yarn having an elongation of 20 to 55%, the strength in the longitudinal direction of the fiber is 3.2 to 8.0 cN / dtex, the average continuous strength and elongation product is 6.0 or more, the minimum value is 5.0 or more, and the CV% is 4.0 or less.

4. The polyamide multifilament according to claim 1 or 2, in which the highly oriented undrawn yarn has an elongation of 60 to 90%, the strength in the longitudinal direction of the fiber is 2.1 to 6.0 cN / dtex, the average continuous strength-elongation product is 5.0 or more, the minimum value is 4.0 or more, and the CV% is 3.5 or less.

5. A fabric comprising in part the polyamide multifilament according to claim 1.

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