Knitted fabrics

Abstract

This invention provides a comfortable underwear that feels good against the skin in hot and humid environments, providing a cooling sensation upon contact with the skin (cooling sensation upon contact), and preventing the fabric from sticking to the skin when sweating (skin detachment). This can be achieved through a knitted fabric composed of polyamide fibers and polyurethane elastic fibers, wherein the polyamide fiber monofilaments have a flat, multi-lobed cross-sectional shape and a monofilament fineness of 0.8 dtex or less.

Description

Technical Field

[0001] This invention relates to knitted fabrics. Background Technology

[0002] Polyamide and polyester fibers, as synthetic fibers, are widely used in clothing and industrial applications due to their excellent mechanical and chemical properties.

[0003] In recent years, influenced by the increased environmental awareness brought about by global warming countermeasures such as the SDGs, and especially as a heatstroke prevention measure in hot and humid summer environments, functional clothing materials that do not cause uncomfortable stickiness to the skin, have a comfortable wearing feel, and provide a cooling sensation have received attention and various inventions have been made.

[0004] For example, Patent Document 1 reports on cool-feel stockings and underwear that use "polyamide fibers with a flat cross-section containing 0.5 to 8% by weight of inorganic compounds" and specify "the K value obtained by dividing qmax, which represents the cool-feeling sensation, by the mass per unit area".

[0005] In addition, Patent Document 2 reports a knitted fabric that combines coolness and breathability by using "a fiber made by blending polyester fiber containing 1.0 to 5.0% by weight of titanium oxide and having one or more protrusions on a flat cross-section with cellulose fiber".

[0006] In addition, Patent Document 3 reports woven / knitted fabrics using flat, multi-leaf cross-section polyamide fibers containing 0 to 6% by weight of a moisture absorbent.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2004-107809

[0010] Patent Document 2: Japanese Patent Application Publication No. 2012-211405

[0011] Patent Document 3: Japanese Patent Application Publication No. 2016-65328 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] However, in the prior art of Patent Document 1, the maximum value of qmax, representing the cooling sensation upon contact, is 0.29 W / cm². 2On the left and right, sufficient cooling sensation cannot be achieved through contact. In addition, although adding inorganic compounds can give it a powder-like feel, the physical unevenness, which exists as fine particles on the fiber surface, does not significantly change the friction with the skin surface and cannot suppress the fabric from sticking to the skin when sweating.

[0014] In the prior art of Patent Document 2, by blending 56 dtex polyester fiber with cellulose fiber of the same fineness, the resulting knitted fabric is thicker and feels stiff and uncomfortable against the skin. Furthermore, the maximum qmax at 20°C and 65%RH is 0.28 W / cm². 2 The desired cool sensation was not achieved.

[0015] The known technology in Patent Document 3 involves woven / knitted fabrics made of polyamide fibers with a flat, multi-lobed cross-section, but it does not specify the exact knitted fabric structure. Compared to circular cross-sections, polyamide fibers with irregular cross-sections have a larger surface area, making orientation and crystallization difficult. This results in a looser fiber structure, leading to uneven dyeing defects such as vertical and horizontal stripes during fabric dyeing, hindering practical application. Furthermore, its cooling sensation upon contact is also insufficient.

[0016] In the case of cool-feeling knitwear, current technology cannot yet achieve a fully satisfactory balance between coolness and comfortable wear.

[0017] This invention provides a knitted fabric that does not have the disadvantages of other fabrics, has excellent practicality, a good feel against the skin, and provides a cooling sensation upon contact with the skin (cooling sensation upon contact). The fabric does not stick to the skin when sweating (skin detachment), and can provide comfortable clothing such as underwear.

[0018] Problem-solving methods

[0019] The present invention solves the above-mentioned problems by adopting the following solution.

[0020] (1). A knitted fabric, wherein the cross-sectional shape of the monofilament of the polyamide fiber is a flat multi-leaf shape and the fineness of the monofilament of the polyamide fiber is less than 0.8 dtex.

[0021] (2). The knitted fabric described in (1) above has a total fineness of 66 dtex or less for the polyamide fibers.

[0022] (3). As described in (1) or (2) above, the total fineness of the polyurethane elastic fiber is 0.5 to 1.0 times that of the total fineness of the polyamide fiber.

[0023] (4). The knitted fabric as described in any one of (1) to (3) above, wherein the weight per unit area of ​​the knitted fabric blank is 100 g / m².2 ~200g / m 2 The qmax measured based on the contact cooling sensation evaluation according to JIS L1927 (2020) is 0.320 W / cm. 2 above.

[0024] Invention Effects

[0025] The knitted fabric of the present invention has a good skin feel in high temperature and high humidity environments, feels cool when in contact with the skin (cooling sensation upon contact), and does not stick to the skin when sweating (skin detachment), thus enabling the manufacture of comfortable clothing made of knitted fabric. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the cross-sectional shape of a single filament of the flat, multi-leaf-shaped polyamide fiber of the present invention.

[0027] Figure 2 This is a schematic diagram showing the shape of the discharge hole of the spinning spinneret used in an embodiment of the present invention. Detailed Implementation

[0028] The knitted fabrics of the present invention are made of polyamide fibers and polyurethane elastic fibers.

[0029] The mechanism of the desired cooling sensation is that when the fabric comes into contact with the skin, heat moves to the cooler fabric side, resulting in a cooling sensation. Materials with high thermal conductivity, thermal diffusivity, and heat of vaporization of moisture (hygroscopicity) will exhibit a high degree of cooling sensation upon contact.

[0030] For example, the thermal conductivity of materials used in clothing that come into contact with the skin is as follows: rayon (0.58), cotton (0.54), polyamide (0.38), polyurethane (0.30), and polyester (0.18). The values ​​in parentheses are thermal conductivity (unit: W / m·K).

[0031] Additionally, the moisture absorption rates are as follows: rayon (11.0), cotton (11.0), polyamide (4.5), polyurethane (1.0), and polyester (0.4). The values ​​in parentheses are the standard moisture regain (unit: %).

[0032] Furthermore, while high hydrophobicity is an important factor for skin retraction, hydrophobicity and hygroscopicity are inversely related. Rayon and cotton are difficult to dry due to their absorbency, resulting in poor skin retraction. On the other hand, polyester, polyurethane, and polyamide exhibit excellent quick-drying properties, thus providing excellent skin retraction when sweating. Therefore, a combination of polyamide and polyurethane is the most suitable material as it combines a cooling sensation upon contact with good skin retraction.

[0033] In addition, polyurethane has a high specific heat capacity, which is the product of its specific heat and density, i.e., its volumetric specific heat is as high as 2045 kJ / m³. 3The high volumetric heat of material K means that its temperature is less prone to change. That is, it exhibits slow temperature response, creating a temperature difference with body temperature and thus providing a cooling effect. Therefore, in this invention, polyurethane elastic fibers are actively used as a material to further enhance the cooling sensation upon contact.

[0034] In addition, polyurethane elastic fibers are most suitable for use with polyamide fibers to make knitted fabrics stretchy.

[0035] In this invention, knitted fabrics composed of polyamide fibers and polyurethane elastic fibers were further studied. Through the modification of polyamide fibers (cross-sectional shape, monofilament ultrafineness), a high level of coolness and comfortable wearing experience that was previously unattainable was achieved.

[0036] The polyamide fibers used in this invention are fibers composed of polymers in which hydrocarbon groups are linked by amide bonds in the main chain. Specific polymers include polycaprolactam (Nylon 6), polyhexamethylene adipamide (Nylon 66), polyhexamethylene sebacate (Nylon 6,10), polybutylene adipamide (Nylon 4,6), and polypentanediamine adipamide (Nylon 5,6).

[0037] Polyamides are highly hygroscopic materials in synthetic fibers because their hydrophilic amide groups are located in the main chain of the molecule. From the viewpoint that hygroscopicity is an important factor in providing a cool feeling upon contact, nylon 6, nylon 66, and nylon 5,6 are particularly preferred.

[0038] Polyamides may also contain appropriate amounts of matting agents and hygroscopic agents. As matting agents, inorganic compounds can be used, such as titanium dioxide, barium sulfate, aluminum oxide, zirconium oxide, calcium oxide, and magnesium oxide. From the viewpoint of productivity in manufacturing polyamide fibers and the cooling sensation upon contact, titanium dioxide and barium sulfate are preferred. By containing these inorganic compounds, the knitted fabric can have a matte or powdery feel. However, since the presence of inorganic compounds hinders the secondary crystallization of the polymer, the strength of the precursor fiber decreases with increasing content; therefore, a content of 0.5% to 2.0% by mass is preferred.

[0039] Examples of hygroscopic agents include polyvinylpyrrolidone (PVP), polyether amide, polyalkylene glycol, and polyether ester amide, with PVP being particularly preferred, and a preferred content of 0 to 5% by mass.

[0040] Furthermore, given the concern for environmental issues, the use of plant-derived biopolymers or recycled polymers in this invention is preferred from the viewpoint of reducing environmental impact. It is also preferred that the polyamide used in this invention be a recycled polymer; recycled polymers obtained through any of the methods of chemical regeneration, material regeneration, and thermal regeneration can be used.

[0041] Polyurethane elastic fibers contain polyurethane polymers. These polyurethane polymers are obtained through a known urethane esterification reaction technique: a prepolymer obtained from the reaction of a polymeric diol with a diisocyanate is subjected to a chain extension reaction using a multifunctional, active hydrogen-containing compound as a chain extender. Preferably, the polymeric diol is a polyether diol, a polyester diol, or a polycarbonate diol. The molecular weight of the polymeric diol is preferably 1000 to 8000. The diisocyanate is a compound having two isocyanate groups within its molecule; examples include aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates.

[0042] like Figure 1 As shown, the monofilament cross-sectional shape of the polyamide fiber constituting the knitted fabric of the present invention is a flat, multi-lobed shape with multiple protrusions and depressions. By having a flat, multi-lobed shape, the contact area between the highly thermally conductive polyamide fiber and the skin surface can be increased when the knitted fabric is made, resulting in a better cooling sensation. Furthermore, the numerous depressions provide a very smooth feel against the skin, and the capillary effect caused by the micropores enhances water absorption. Thus, even when sweating, the fabric exhibits excellent skin detachment and a cool, refreshing feel, providing a comfortable wearing experience even in hot and humid summer environments.

[0043] Even with a flat shape without bumps or recesses, a cooling sensation can be achieved due to the increased contact area, but the fabric may stick to the skin when sweating.

[0044] The flat, multi-leaf shape preferably has 4 or more leaves, more preferably 6 to 8 leaves. Here, the number of leaves refers to the number of protrusions in the fiber cross-section.

[0045] Flatness of a flat, multi-lobed shape ( Figure 1 The flatness (A / B) is preferably 1.50 to 2.50. Here, flatness is the value obtained by dividing the length of the longer side of the circumscribed quadrilateral (rectangle) of the cross-sectional shape by the length of the shorter side. The circumscribed quadrilateral (rectangle) is the smallest rectangle enclosing the flat, multi-lobed shape. By making the flatness 1.50 or higher, the contact area with the skin surface can be increased, resulting in increased heat flux per unit area, thereby improving the cooling sensation upon contact. If the flatness is larger, it becomes softer against the skin compared to a perfectly round shape (flatness 1.0), but the strength of the raw yarn tends to decrease. Since the strength of the fiber can be guaranteed, the breaking strength of the knitted fabric can be improved; therefore, flatness is preferably 2.50 or less. Flatness is more preferably 1.50 to 2.30, and even more preferably 1.60 to 2.00.

[0046] The irregularity of the flat, multi-lobed shape is explained. The convex and concave vertices of the flat, multi-lobed shape are determined. When the number of lobes is even, line segments are drawn between the convex vertices on the longer side of the circumscribed quadrilateral (rectangle) and their symmetrical convex vertices. Similarly, line segments are drawn between the symmetrical concave vertices for the concave vertices. Specifically, line segments connecting opposite convex vertices are drawn, separated by the centerline connecting the centers of the shorter sides of the circumscribed quadrilateral (rectangle). In other words, line segments connecting concave vertices and convex vertices are drawn in a manner that makes them nearly parallel, using the shorter side of the circumscribed quadrilateral (rectangle) as the axis. Figure 1 Taking a flat octagonal cross-section as an example, first determine the concave vertices (Q1~Q4) and convex vertices (P1~P8). Then, draw line segments connecting convex vertex P1 to convex vertex P4, concave vertex Q1 to concave vertex Q3, convex vertex P2 to convex vertex P5, concave vertex Q2 to concave vertex Q4, and convex vertex P3 to convex vertex P6, respectively, starting from the left. Figure 1 In the example of the flat octagonal cross-section shape, the lengths of the line segments drawn between the symmetrical convex vertices are L1, L2, and L3. The lengths of the line segments drawn between the symmetrical concave vertices are l1 and l2. Furthermore, when the number of lobes is odd, line segments are drawn between the concave vertices and between the convex vertices in a manner that makes them nearly parallel, using the shorter side of the circumscribed quadrilateral (rectangle) as the axis.

[0047] The anisotropy 1, representing leaf depth, is preferably 1.30 to 1.60, and the anisotropy 2, representing leaf length, is preferably 1.05 to 1.25. Here, the anisotropy 1 is calculated by dividing the length (B) of the shorter side of the circumscribed quadrilateral (rectangle) by the length of the shortest line segment connecting the vertices of the concave portion. Figure 1 The value is obtained by taking the shorter of l1 and l2. By setting the anisotropy 1 to 1.30–1.60, the water absorption caused by capillary action can be improved, and the skin detachment during sweating can be improved. Anisotropy 2 is the length of the second longest line segment connecting the convex vertex of the long side of the circumscribed quadrilateral (rectangle) to the convex vertex symmetrical to it. Figure 1 The longer of L2 and L3) is divided by the shortest line segment connecting the vertices of the concave part to each other. Figure 1 The value is obtained by selecting the shorter of l1 and l2. By setting the irregularity 2 to 1.05 to 1.25, the knitted fabric makes point contact with the skin surface, resulting in a refreshing feel. Additionally, in Figure 1In the diagram, l1 represents the length of the shortest line segment connecting the vertices of the concave part, L1 represents the length of the longest line segment connecting the vertices of the convex part, L2 represents the length of the second longest line segment connecting the vertices of the convex part, and L3 represents the length of the third longest line segment connecting the vertices of the convex part.

[0048] The polyamide fiber monofilaments constituting the knitted fabric of this invention have a fineness of 0.80 dtex or less. By reducing the fineness of the monofilaments while maintaining the overall fineness, the number of filaments increases, thus increasing the contact area between the knitted fabric and the skin surface. This significantly improves the cooling sensation dependent on the amount of heat movement per unit area of ​​the knitted fabric. Furthermore, because the fiber cross-section is a flat, multi-lobed shape, the numerous and numerous concave areas are finer and more numerous, thereby promoting capillary action and increasing water absorption, resulting in a soft and refreshing feel.

[0049] By forming flat, multi-lobed polyamide fibers with monofilament fineness within this range, a smooth skin feel, a cooling sensation upon contact, and excellent skin detachment when sweating can be achieved, ensuring a comfortable wearing experience even in hot and humid summer environments.

[0050] On the other hand, if the monofilament fineness is too fine, the knitted fabric will lose its stiffness, skin detachment will decrease, and physical strength will also decrease. Therefore, a monofilament fineness of 0.40 dtex to 0.80 dtex is preferred.

[0051] The total fineness of the polyamide fibers constituting the knitted fabric of the present invention is preferably 66.0 dtex or less. By setting it to 66.0 dtex or less, a knitted fabric with a good skin feel can be designed. Especially in the hot and humid environment of summer, thinner knitted fabrics are preferred, as the thinner the fabric, the softer it feels against the skin. Therefore, a total fineness of 56.0 dtex or less is more preferred, and 44.0 dtex or less is even more preferred. In addition, from the viewpoint that it can be knitted (manufactured) using a common knitting machine gauge, a range of 15.0 to 44.0 dtex is preferred.

[0052] The preferred blending rate of polyurethane elastic fibers in knitted fabrics is 15% to 35% by weight. By setting the blending rate within this range, the knitted fabrics can be given resilience while achieving a high degree of coolness upon contact and a very smooth wearing experience.

[0053] The knitted fabric of the present invention preferably has a unit area mass of 100 g / m². 2 ~200g / m 2 The qmax, based on the JIS L1927 (2020) standard for evaluation of contact coolness, is 0.320 W / cm². 2The above. By setting it within this range, even thin materials can achieve the "smooth skin feel, cooling sensation upon contact, and skin-repellent properties when sweating" characteristic of flat, multi-lobed polyamide fibers, ensuring comfortable wear even in hot and humid summer environments. A more preferable value is a basis weight of 180 g / m². 2 Below, qmax is 0.350 W / cm 2 The above. As for the upper limit of qmax, a higher value is preferred, but the practical range for clothing manufacturing is 0.700W / cm². 2 the following.

[0054] The knitted fabric of this invention can be knitted using a conventional knitting machine. There are no particular limitations on the fabric structure; it can be circular knit, weft knit, or warp knit. Preferred circular knit and weft knit structures include plain knit, rib knit, double knit, purl knit, tuck knit, float knit, one-sided rib knit, lace knit, fringe knit, knit miss, and single-knot knit. Examples of warp-knitted fabric structures include single tricot knit, single cord knit, single atlas knit, double tricot knit, double atlas knit, double cord knit, half tricot knit, fleece knit, and jacquard knit. From the perspective of increasing the contact area with the skin to enhance the cooling sensation, a relatively smooth fabric structure with fewer bumps, such as plain knit or tricot knit, is preferred, using a combination of polyamide and polyurethane elastic fibers.

[0055] From the viewpoint of increasing the contact area with the skin surface using a conventional knitting machine, the knitting of the present invention preferably uses a gauge of 36 or higher. As an upper limit, 60 or lower is more preferably preferred.

[0056] The polyamide filaments used to manufacture the knitted fabrics of the present invention will be described.

[0057] Although the shrinkage rate varies depending on the boiling water shrinkage rate of the polyamide precursor yarn, the preferred single filament fineness of the polyamide precursor yarn is 0.75 dtex or less. Furthermore, the preferred total fineness of the polyamide precursor yarn is 60 dtex or less. By setting the single filament fineness and total fineness of the polyamide precursor yarn within the above ranges, the single filament fineness of the polyamide fibers constituting the knitted fabric of the present invention can be 0.80 dtex or less, and the total fineness is 66.0 dtex or less.

[0058] The initial elongation stress obtained from the tensile test of the polyamide precursor, i.e. from the so-called stress-strain curve, is preferably 0.8 cN / dtex to 1.2 cN / dtex when the elongation is 5%.

[0059] The stress at 5% elongation serves as a benchmark for confirming the orientation and crystallization state of the fiber during the manufacturing stage. Therefore, by setting the stress at 5% elongation of the polyamide filament in this invention to 0.8 cN / dtex or higher, the defect of uneven dyeing in knitted fabrics can be suppressed, resulting in high-quality knitted fabrics. More preferably, the stress at 5% elongation of the polyamide filament is 0.9 cN / dtex or higher, and even more preferably 1.0 cN / dtex or higher. On the other hand, the higher the stress at 5% elongation, the lower the fiber elongation, which can induce fuzzing problems in higher processing steps. Therefore, the stress at 5% elongation of the polyamide filament is preferably 1.2 cN / dtex or lower, which can significantly suppress fuzzing defects and obtain high-quality knitted fabrics.

[0060] Furthermore, from the viewpoint of advanced processing, the preferred elongation of the polyamide precursor is 35% to 48%. The strength of the polyamide precursor is preferably 3.0 cN / dtex or higher, more preferably 3.5 cN / dtex or higher.

[0061] From the perspective of advanced processing, the preferred entanglement of polyamide precursor fibers is 30 to 50. The entanglement value referred to here is a value determined by the method described in section 8.15 of JIS L1013 (2021). A lower entanglement value makes it easier for fuzz to form during advanced processing, while a higher entanglement value results in finer lines, thus affecting the striped appearance of the fabric and leading to poor aesthetics. A more preferred entanglement value is 40 to 50.

[0062] The manufacturing process of polyamide precursor fibers is explained.

[0063] Compared to polyester fibers, polyamide fibers are more difficult to maintain specific cross-sectional shapes and to spin stably, especially as the finer the monofilament fineness, the greater the difficulty. Therefore, in the manufacture of polyamide precursors supplied to the knitted fabrics of this invention, cross-sectional shapeability and spinnability become very important.

[0064] The prior art described in Patent Document 3, even at extremely fine finishes, suffers from poor spinnability of the yarn exiting the spinneret, leading to filament breakage and making stable spinning extremely difficult; a single filament fineness of 0.9 dtex is the limit. Examples of methods to improve poor spinnability include increasing the melt temperature to improve polymer flowability, or reducing the ratio of the spinneret's exit speed to its draw speed (hereinafter referred to as the spinning draw ratio) to a level that ensures spinnability. Increasing the melt temperature of the former leads to a decrease in polymer melt viscosity and / or an increase in the atmosphere temperature directly below the spinneret, resulting in a fiber cross-sectional shape that is nearly circular, failing to achieve the desired extremely fine, flat, multi-lobed cross-sectional shape. Furthermore, reducing the spinning draw ratio of the latter fails to achieve the desired 5% elongation stress.

[0065] Therefore, by significantly increasing the number of yarns discharged from the spinning spinneret to more than three per spinneret, the present invention doubles the amount of polymer flowing into the spinning spinneret compared to the past (= discharge volume increase), thereby increasing the heat carried in by the molten polymer without increasing the melting temperature, thus maintaining the atmosphere temperature directly below the spinneret, and solving the problems of cross-section formation and spinnability for special cross-sectional shapes.

[0066] Higher melt temperatures improve polymer fluidity and spinnability, but reduce cross-section forming properties. Therefore, by appropriately controlling the melt temperature and the atmosphere temperature directly below the spinneret, polyamide precursor fibers can achieve good spinnability and cross-section forming properties.

[0067] The preferred melting temperature is 20°C to 60°C higher than the melting point of the polyamide. More preferably, it is 255°C to 270°C for nylon 6 polymer, 280°C to 295°C for nylon 66 polymer, and 275°C to 290°C for nylon 5 and 6 polymers. Furthermore, the preferred atmosphere temperature directly below the spinneret is 220°C to 250°C.

[0068] In order to control the stress within the range when the elongation is 5%, the value obtained by dividing the drawing speed by the spinneret discharge line speed, i.e., the spinning draw ratio, is set to 1500 or higher.

[0069] Polyamide precursor fibers can be obtained from, for example Figure 2 The fiber shown is manufactured by melt spinning through discharge orifices composed of multiple slits. Due to the complex shape of the spinneret discharge orifices, the increased cross-sectional area of ​​each orifice, and the lower discharge linear velocity of the spinneret, there is a tendency for orientation crystallization to be difficult to achieve. That is, compared with circular cross-section fibers, flat multi-lobed cross-section fibers are more prone to loose fiber structure, and if knitted fabrics are dyed, uneven dyeing becomes very obvious.

[0070] Therefore, by setting the spinning draw ratio to 1500 or higher, orientation crystallization can be promoted, resulting in a denser fiber structure and suppressing uneven dyeing. Specifically, the stress at 5% elongation of the polyamide precursor can be controlled to be 0.8 cN / dtex to 1.2 cN / dtex. A more preferred spinning draw ratio is 1600 or higher.

[0071] Furthermore, if the spinneret exit speed decreases, the tension (spinning tension) experienced by the fiber before it is pulled onto the take-up roller tends to increase. This results in fiber breakage due to poor spinnability, making stable spinning extremely difficult. Therefore, by maintaining a spinning draw ratio below 1700, stable spinning tension and good spinnability are achieved.

[0072] For polyamide precursor fibers, good spinnability and grade (suppression of uneven dyeing) can be obtained by controlling the spinning draw ratio at 1500-1700.

[0073] In addition, the spinning draw ratio is related to the tension experienced by the fiber from the time it exits the spinneret until it is cooled and pulled onto the take-up roller. The larger the spinning draw ratio, the greater the tension experienced by the fiber (= spinning tension).

[0074] Here, the spinneret discharge linear velocity refers to the value obtained by dividing the discharge volume of polymer discharged from the discharge orifice of the spinning spinneret per unit time by the cross-sectional area of ​​the discharge orifice.

[0075] In order to control the degree of interlacing of the above-mentioned polyamide precursor fibers within the range of 30 to 50, interlacing treatment is performed by an interlacing device before stretching.

[0076] The merging device can use any known device, preferably a double-hole cross-line parallel flow pattern (EDV nozzle) or a single-hole inclined flow pattern (PolyJet nozzle).

[0077] In the case of a cross-flow interlacing device with two orifices, a cross-flow nozzle with a jet orifice diameter of 0.8 mm to 1 mm, a jet orifice angle between the two orifices of 100° to 150°, and an inclined jet angle relative to the moving yarn of 0° to 45° is preferably used. Furthermore, the compressed air pressure is preferably 0.15 MPa to 0.35 MPa. In the case of a cross-flow interlacing device with a single orifice, a cross-flow nozzle with a jet orifice diameter of 0.8 mm to 1.5 mm and an inclined jet angle of 0° to 45° is used. Furthermore, the compressed air pressure is preferably 0.10 MPa to 0.30 MPa.

[0078] The resulting knitted fabric offers a comfortable feel and a high degree of coolness to the touch, making it well-suited for applications such as underwear.

[0079] Example

[0080] The present invention will now be described in detail with reference to the embodiments, but the present invention is not limited to these embodiments. First, the measurement methods and evaluation methods used in the present invention will be described.

[0081] A. Fineness

[0082] (a) Total fineness of polyamide precursor fibers

[0083] The fiber sample was wound 200 times on a measuring machine with a frame circumference of 1.125m and a tension of 1 / 30cN × nominal tex to make a skein.

[0084] Dry at 105℃ for 60 minutes, transfer to a desiccator, cool at 20℃ and 55%RH for 30 minutes, and then determine the quality of the skein.

[0085] The mass per 10,000 meters was calculated from the obtained values; for Nylon 6, 4.5% was used as the standard moisture regain, and for Nylon 5 and 6, 5.0% was used as the standard moisture regain. The total fiber fineness was then calculated. The measurement was performed four times, and the average value was taken as the total fineness.

[0086] (b) Total fineness of polyamide fibers (fabric disassembly yarns)

[0087] We break down knitted fabrics into polyamide fibers and polyurethane elastic fibers.

[0088] Next, to determine the test load, a provisional total fineness is calculated. A 2g load is applied to the polyamide fibers obtained from disassembling the fabric, and the length L (cm) between two points is measured; then, the fibers are cut at these two points, and their mass W (g) is measured. The provisional total fineness is calculated according to the following formula.

[0089] Next, a load relative to a provisional total fineness of 1 / 10 g / dtex (0.098 cN / dtex) is applied to the polyamide fibers obtained by disassembling the fabric, and the length and mass between the two points are measured in the same manner as above, and the total fineness is calculated according to the following formula.

[0090] Total fineness (disassembled yarn) = W / L × 100000 (dtex)

[0091] (c) Total fineness of polyurethane elastic fibers (fabric disassembly yarns)

[0092] The polyamide fiber and polyurethane elastic fiber were separated from the knitted fabric.

[0093] For polyurethane elastic fibers obtained from disassembled fabric, the length L (cm) between two points is measured under no-load conditions, and then the fibers are cut at these two points and their mass W (g) is measured. The total fineness is calculated using the following formula.

[0094] Total fineness (disassembled yarn) = W / L × 100000 (dtex)

[0095] (d) Monofilament fineness

[0096] Divide the total fineness obtained through (a) to (c) above by the number of filaments, and use the resulting value as the single filament fineness (dtex).

[0097] B. Strength, elongation, and stress at 5% elongation

[0098] Tensile strength-elongation curves of polyamide precursor fibers were plotted according to the tensile strength and elongation requirements of JIS L1013 (2021) Section 8.5. Test conditions: The testing machine was a constant-speed elongation type, with a gripping distance of 50 cm and a tensile speed of 50 cm / min. Additionally, when the tensile strength at break was less than the maximum strength, the maximum tensile strength and the elongation at that point were measured.

[0099] Strength, elongation, and stress at 5% elongation are obtained using the following formula.

[0100] Strength (cN / dtex) = Tensile strength at break (cN) / Total fineness (dtex)

[0101] Elongation (%) = Elongation at break (cm) / Grip interval (cm) × 100

[0102] Stress at 5% elongation (cN / dtex) = Tensile strength at 5% elongation (cN) / Total fineness (dtex).

[0103] C. Blending rate of polyurethane elastic fibers

[0104] Knitted fabrics were measured according to JIS L1030-2 (2012).

[0105] D. Mass per unit area

[0106] The mass per unit area of ​​the knitted fabric was determined in accordance with the mass per unit area specified in Section 8.3 of JIS L1096 (2010).

[0107] E. qmax

[0108] Using a KES-73 and Thermo Lab II, the laboratory temperature and humidity were set to 20°C and 65%RH. Following JIS L1927 (2020), the knitted fabric was placed on the testing platform, ensuring both the platform and the sample material were at room temperature. The sensor section (heat source) of the testing device was set to 20°C above room temperature, and brought into contact with the back side (skin contact side) of the knitted fabric. The maximum heat transfer at this point was measured in W / cm². 2It is denoted as qmax.

[0109] F. Cooling sensation upon contact

[0110] The knitted fabric was cut into 30cm×21cm pieces. The coolness felt by the three subjects when they grasped the fabric was scored in three levels, from 3 (excellent) to 1 (poor). The average score of the three subjects was evaluated using the following A to C scale.

[0111] Evaluations A and B were both judged to have a cooling sensation upon contact.

[0112] Rating A: 3.0 to 2.7 points: Feels very cool.

[0113] Rating B: 2.6 to 2.3 points: A cooling sensation can be felt.

[0114] C rating: Below 2.2 points: I didn't feel any particular cooling sensation.

[0115] G. Skin detachment

[0116] Underwear (round neck, long sleeves) made of knitted fabric was evaluated by 5 participants. The evaluation method involved sitting quietly for 20 minutes in a room set at 20°C and 65%RH, then moving to another room set at 32°C and 60%RH. After 10 minutes of climbing up and down stairs, participants returned to the 20°C, 65%RH room. The fabric's contact with the skin after 1 minute was scored from 3 (excellent) to 1 (poor), and the average score of the 5 participants was evaluated using the following scale: A to D.

[0117] Evaluations A and B indicate good skin detachment during sweating.

[0118] Rating: 3.0 to 2.6 points: Does not adhere to the skin at all.

[0119] B rating: 2.5 to 2.1 points: Slightly adheres to the skin.

[0120] C rating: 2.0 to 1.6 points: Slightly uncomfortable adhesion to the skin.

[0121] D rating: 1.5 to 1.0 points: It adheres to the skin in an uncomfortable way.

[0122] H. Skin feel

[0123] The knitted fabric was cut into 30cm×21cm pieces and placed on the forearms of 3 subjects. The smoothness of the fabric when moving was rated on a scale of 3 (excellent) to 1 (poor). The average score of the 3 subjects was evaluated using the following A to C scale.

[0124] Ratings A and B were both judged as having a good skin feel.

[0125] Rating: 3.0 to 2.7 points: Very smooth to the touch.

[0126] B rating: 2.6 to 2.3 points: You can feel the smooth texture.

[0127] C rating: Below 2.2 points: No noticeable smoothness felt.

[0128] I. Overall Evaluation

[0129] Based on the evaluation results of cooling sensation upon contact, skin detachment, and skin feel, the grades are classified according to the following standards.

[0130] Evaluations A and B are considered to indicate a wearing experience that is "good to the touch, cool to the touch (coolness upon contact), and the fabric does not stick to the skin when sweating (skin detachment)".

[0131] A rating: All ratings are A.

[0132] B rating: The rating for the cooling sensation upon contact is B, or either the skin feel or the skin detachment is B.

[0133] C rating: Any of the following: cooling sensation, skin feel, and skin detachment is a C rating or a D rating.

[0134] J. Fabric Grade

[0135] As an evaluation of fabric quality, the knitted fabric was inspected under normal reflected light.

[0136] W0: No visible uneven staining, good grade.

[0137] W1: Slight staining unevenness exists, but it is still a usable grade.

[0138] W2: Severely uneven dyeing, an unusable grade.

[0139] K. Relative viscosity

[0140] After weighing the sliced ​​sample, it was dissolved in concentrated sulfuric acid (98.0%). The viscosity of a 0.5% by weight solution was measured using an Orstauld viscometer at 25°C.

[0141] L. Cross-sectional shape of polyamide fibers

[0142] Based on the cross-sectional photographs of polyamide fibers (fabric disassembly yarns) (magnification: 400x), as previously described, the following parameters A, B, l1, and L2 were measured for the cross-sectional shapes of all monofilaments, and their respective parameters were calculated. The average values ​​of all calculated monofilament parameters were then used as the polyamide fiber's flatness, irregularity 1, and irregularity 2.

[0143] A: The length of the longer side of the circumscribed quadrilateral (rectangle) of the cross-section.

[0144] B: Length of the shorter side of the circumscribed quadrilateral (rectangle) of the cross-section.

[0145] l1: The length of the shortest line segment connecting the vertices of the concave portion.

[0146] L2: The length of the second longest line segment connecting the vertices of the convex part.

[0147] Flatness = A / B

[0148] Irregularity 1 = B / l1

[0149] The degree of irregularity is 2 = L2 / l1.

[0150] Cross-connectivity (CF value)

[0151] Intersection degree was determined in accordance with section 8.15 of JIS L 1013 (2021).

[0152] (a) Apparatus: entanglements-testor R2040 and electronic tension meter R-1192 (both manufactured by Tsuelbeca Overseas Co., Ltd.)

[0153] (b) Measurement conditions: yarn travel speed 2.4 m / min

[0154] Winding speed: 17.6 m / min; Winding time: 3.4 seconds; Winding length: 99.7 cm.

[0155] NO. Show 10×10cm, Full Scale 25g

[0156] (c) Triggering tension:

[0157] (Total fineness dtex × 17.64 mN / dtex + Total fineness dtex × 88.2 mN / dtex / Number of filaments)

[0158] (d) When the average length of each intersection point is denoted as the average intersection point length A (mm), the degree of intersection = 1000 / A.

[0159] (e) Suspend the weights, apply the specified trigger tension to make them move, and adjust the tension indicator to the initial load. Set the test counter to N=50, and take the average value of the measurement results as the degree of cross-linking.

[0160] [Example 1]

[0161] (Manufacturing of polyamide precursor fibers)

[0162] The chips are prepared by mixing "nylon 6 chips with a relative viscosity of 3.3 without additives" and "nylon 6 chips mixed with 20% by mass of polyvinylpyrrolidone (hereinafter referred to as PVP)" at a PVP content of 5% by mass. The chips are melted and discharged from the spinneret at an atmosphere temperature of 220°C (the temperature of the heater under the spinneret, which has a variable set temperature, is set to 220°C) with the atmosphere directly below the spinneret. The amount of yarn produced is 41.8 g / min from each of the 24 holes of the spinneret. Figure 2 (a) The spinneret has 144 holes, which is equivalent to the amount of 6 yarns, and discharges through the discharge holes shown in (a).

[0163] Next, the upper section of the internal air-cooled annular cooling device was set to 22 m / min and the lower section to 40 m / min. The yarn was cooled with 18°C ​​cooling air. After applying oil using an oiling guide, a cross-linking device (a cross-linking nozzle with a double-hole cross-line parallel flow pattern (0.9mm nozzle diameter, 120° nozzle angle between the two holes, and 0° tilting angle) was used with compressed air at 0.25 MPa to bundle and cross-link the two yarns. The first guide roller was set at 3531 m / min, and the spinning draw ratio was 1639. The yarn was stretched to a stretch ratio of 1.3, and then heat-set at 155°C. The 33dtex / 48f flat octagonal cross-section nylon 6 multifilament (polyamide precursor) was wound into three strands at a winding speed of 4500 m / min. The resulting polyamide precursor had the following properties: stress at 5% elongation 1.1 cN / dtex, strength 4.8 cN / dtex, elongation 45%, boiling water shrinkage 12.0%, and interlacing degree 40.

[0164] (Manufacturing of knitted fabrics)

[0165] The obtained polyamide precursor yarn was used for the front comb, and 22.0 dtex polyurethane elastic fiber (HYOSONG Creora registered trademark H350A) was used for the back comb. The fabric was woven on a single-sided warp knitting machine of size 40 with a polyurethane elastic fiber blending rate of 30% by mass to obtain Trico warp-knitted fabric.

[0166] The obtained Trico warp-knitted fabric underwent the following processes sequentially: continuous scouring at 80℃, intermediate setting at 190℃; light blue dyeing at 98℃ using Milling-type acid dyes; and final setting at 170℃ to obtain a warp-knitted fabric with an areal density of 170 g / m². The characteristics of the resulting knitted fabric are shown in Table 1. This knitted fabric exhibits excellent coolness, tactile feel, and skin-peeling properties, fully satisfying the requirements for comfortable wear, and its fabric quality is also excellent.

[0167] [Example 2]

[0168] Except for the use of chips prepared by mixing "chemically recycled nylon 6 chips with a relative viscosity of 3.3 without additives" and "nylon 6 chips mixed with 20% by mass of PVP" at a PVP content of 5% by mass," spinning was performed in the same manner as in Example 1 to obtain 33 dtex / 48f flat octagonal cross-section nylon 6 multifilament. Knitted fabrics were manufactured in the same manner as in Example 1 to obtain Trico warp-knitted fabrics, the fabric properties of which are shown in Table 1.

[0169] [Example 3]

[0170] Except for using chips prepared by mixing "nylon 6 chips with a relative viscosity of 2.6 and 1.6% by mass titanium oxide" and "nylon 6 chips mixed with 20% by mass PVP" at a PVP content of 5% by mass, spinning was performed in the same manner as in Example 1 to obtain 33 dtex / 48f flat octagonal cross-section nylon 6 multifilament. Knitted fabrics were manufactured in the same manner as in Example 1 to obtain Trico warp-knitted fabrics, the fabric properties of which are shown in Table 1.

[0171] [Example 4]

[0172] Except for using only nylon 6 chips with a relative viscosity of 3.3 without additives, spinning was performed in the same manner as in Example 1 to obtain nylon 6 multifilaments with a flat octagonal cross-section of 33 dtex / 48f. Knitted fabrics were manufactured in the same manner as in Example 1 to obtain tricot warp-knitted fabrics, the fabric properties of which are shown in Table 1.

[0173] [Example 5]

[0174] Nylon 5,6 chips with a relative viscosity of 2.8 without additives and nylon 5,6 chips mixed with 20% by mass of PVP were used to prepare chips with a PVP content of 5% by mass. Melting was performed at a melting temperature of 275°C and an atmosphere temperature directly below the spinneret at 275°C (the temperature of the variable-temperature heater below the spinneret was also set to 275°C). Otherwise, spinning was performed in the same manner as in Example 1 to obtain 33 dtex / 48f flat octagonal cross-section nylon 5,6 multifilament. Knitted fabric was manufactured in the same manner as in Example 1 to obtain Trico warp-knitted fabric, the fabric properties of which are shown in Table 1.

[0175] [Table 1]

[0176]

[0177] [Example 6]

[0178] Except for the amount of yarn discharged from each spinneret through 36 holes, resulting in a total of 216 holes (equivalent to 6 yarns), spinning was performed in the same manner as in Example 1 to obtain a flat octagonal cross-section nylon 6 multifilament of 33 dtex / 72f. Knitted fabrics were manufactured in the same manner as in Example 1 to obtain Trico warp-knitted fabrics, the fabric properties of which are shown in Table 2.

[0179] [Comparative Example 1]

[0180] The same mixed chips as in Example 1 were melted at a melting temperature of 265°C and an atmosphere temperature of 220°C directly below the spinneret (the temperature of the heater under the spinneret, which has a variable set temperature, was set to 220°C). The spinneret discharged in the amount of one yarn from 34 holes in each spinneret, resulting in a total of 136 holes with the amount of four yarns (42.2 g / min).

[0181] Next, the upper section of the internal air-cooled annular cooling device was set to 22 m / min, and the lower section to 40 m / min. The yarn was cooled with cooling air at 18°C. After applying oil using an oiling guide, the yarn was interlaced using a interlacing device. The yarn was pulled at a first guide roller speed of 2290 m / min and a spinning draw ratio of 1550, and stretched at a stretch ratio of 1.7. After heat setting at 155°C, the 33 dtex / 34f flat eight-lobed nylon 6 multifilament (polyamide precursor) was wound into four yarns at a take-up speed of 4000 m / min. Knitted fabric was manufactured in the same manner as in Example 1, resulting in a Trico warp-knitted fabric. The fabric properties are shown in Table 2.

[0182] [Comparative Example 2]

[0183] The same mixed chips as in Example 1 were melted at a melting temperature of 265°C and an atmosphere temperature of 220°C directly below the spinneret (the temperature of the heater under the spinneret, which has a variable set temperature, was set to 220°C), and discharged from the spinneret (42.2 g / min), with one yarn amounting to 26 holes in each spinneret. Figure 2 (a) The spinneret has 104 holes, which is equivalent to the amount of 4 yarns, and discharges through the discharge holes shown in (a).

[0184] Next, the upper section of the internal air-cooled annular cooling device was set to 22 m / min, and the lower section to 40 m / min. The yarn was cooled with cooling air at 18°C. After applying oil using an oiling guide, the yarn was interlaced using a interlacing device. The yarn was pulled at a first guide roller speed of 2268 m / min and a spinning draw ratio of 1178, and stretched at a stretch ratio of 1.65. After heat setting at 155°C, the 33 dtex / 26f flat octagonal cross-section nylon 6 multifilament was wound into four yarns at a take-up speed of 4000 m / min. The knitted fabric was manufactured in the same manner as in Example 1, resulting in a Trico warp-knitted fabric. The fabric properties are shown in Table 2.

[0185] [Table 2]

[0186]

[0187] [Example 7]

[0188] (Knitwear manufacturing)

[0189] Using the polyamide fiber (33dtex / 48f flat octagonal cross-section nylon 6 multifilament) and 22dtex polyurethane elastic fiber (HYOSONG Creora registered trademark H350A) obtained in Example 1, a plain knit fabric (generally referred to as "naked polyurethane plain knit" because it incorporates polyurethane elastic fiber) was knitted on a size 40 single-jersey circular knitting machine. The obtained fabric underwent scouring, dyeing, and finishing processes similar to those in Example 1, yielding a surface area weight of 105 g / m². 2 The bare ammonia plain knit fabric was obtained. The properties of the resulting knitted fabric are shown in Table 3.

[0190] [Example 8]

[0191] In addition to adopting Figure 2 Except for the discharge hole shown in (b), spinning was performed in the same manner as in Example 1 to obtain nylon 6 multifilament with a flat four-leaf cross-section of 33 dtex / 48f. A knitted fabric was manufactured in the same manner as in Example 7 to obtain a plain knit fabric. The properties of the obtained knitted fabric are shown in Table 3.

[0192] [Example 9]

[0193] In addition to adopting Figure 2 Except for the discharge hole shown in (c), spinning was performed in the same manner as in Example 1 to obtain a flat hexagonal cross-section nylon 6 multifilament of 33 dtex / 48f. A knitted fabric was manufactured in the same manner as in Example 7 to obtain a plain knit fabric. The properties of the obtained knitted fabric are shown in Table 3.

[0194] [Comparative Example 3]

[0195] Except for the use of rectangular discharge holes (not shown), spinning was performed in the same manner as in Example 1 to obtain 33 dtex / 48f flat cross-section nylon 6 multifilament. A knitted fabric was manufactured in the same manner as in Example 7 to obtain a plain knit fabric. The properties of the obtained knitted fabric are shown in Table 3.

[0196] [Comparative Example 4]

[0197] Except for the use of a circular discharge hole (not shown), spinning was performed in the same manner as in Example 1 to obtain a 33 dtex / 48f circular cross-section nylon 6 multifilament. A knitted fabric was manufactured in the same manner as in Example 7 to obtain a plain knit fabric. The properties of the obtained knitted fabric are shown in Table 3.

[0198] [Table 3]

[0199]

[0200] [Example 10]

[0201] Except for changing the feeding tension of the polyurethane elastic fibers, the knitted fabric was manufactured in the same manner as in Example 1, resulting in a Trico warp-knitted fabric with a polyurethane elastic fiber blending rate of 16% by mass. The properties of the obtained knitted fabric are shown in Table 4.

[0202] [Example 11]

[0203] Using 11 dtex polyurethane elastic fiber (HYOSONG Creora registered trademark H350A), and varying the feed tension, a knitted fabric was manufactured in the same manner as in Example 1, resulting in a Trico warp-knitted fabric with a polyurethane elastic fiber blend of 30% by mass. The properties of the resulting knitted fabric are shown in Table 4.

[0204] [Table 4]

[0205]

[0206] Explanation of symbols in attached drawings

[0207] A: The length of the longer side of the circumscribed quadrilateral (rectangle) of the cross-section.

[0208] B: Length of the shorter side of the circumscribed quadrilateral (rectangle) of the cross-section.

[0209] L1: Length of the line segment connecting the vertices of the convex part

[0210] L2: Length of the line segment connecting the vertices of the convex part.

[0211] L3: Length of the line segment connecting the vertices of the convex part.

[0212] l1: Length of the line segment connecting the apex of the concave portion

[0213] l2: Length of the line segment connecting the apex of the concave portion

[0214] P1~P8: Vertices of the convex part

[0215] Q1~Q4: Vertex of the concave part

Claims

1. A knitted fabric, wherein the cross-sectional shape of the polyamide fiber monofilament is a flat, multi-lobed shape, and the fineness of the polyamide fiber monofilament is less than 0.8 dtex.

2. The knitted fabric as described in claim 1, wherein the total fineness of the polyamide fibers is 66 dtex or less.

3. In the knitted fabric as described in claim 1 or 2, the total fineness of the polyurethane elastic fibers is 0.5 to 1.0 times that of the total fineness of the polyamide fibers.

4. The knitted fabric as described in claim 1 or 2, wherein the weight per unit area of ​​the knitted fabric preform is 100 g / m². 2 ~200g / m 2 The qmax measured based on the contact cooling sensation evaluation according to JIS L1927 (2020) is 0.320 W / cm. 2 above.

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